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9742079a | 1 | \input texinfo @c -*- texinfo -*- |
c906108c | 2 | @setfilename gdbint.info |
25822942 | 3 | @include gdb-cfg.texi |
03727ca6 | 4 | @dircategory Software development |
e9c75b65 | 5 | @direntry |
c906108c | 6 | * Gdb-Internals: (gdbint). The GNU debugger's internals. |
e9c75b65 | 7 | @end direntry |
c906108c SS |
8 | |
9 | @ifinfo | |
25822942 | 10 | This file documents the internals of the GNU debugger @value{GDBN}. |
c02a867d | 11 | Copyright (C) 1990, 1991, 1992, 1993, 1994, 1996, 1998, 1999, 2000, 2001, |
c91d38aa | 12 | 2002, 2003, 2004, 2005, 2006 |
e9c75b65 | 13 | Free Software Foundation, Inc. |
c906108c SS |
14 | Contributed by Cygnus Solutions. Written by John Gilmore. |
15 | Second Edition by Stan Shebs. | |
16 | ||
e9c75b65 EZ |
17 | Permission is granted to copy, distribute and/or modify this document |
18 | under the terms of the GNU Free Documentation License, Version 1.1 or | |
2a6585f0 | 19 | any later version published by the Free Software Foundation; with no |
e5249f67 AC |
20 | Invariant Sections, with no Front-Cover Texts, and with no Back-Cover |
21 | Texts. A copy of the license is included in the section entitled ``GNU | |
22 | Free Documentation License''. | |
c906108c SS |
23 | @end ifinfo |
24 | ||
25 | @setchapternewpage off | |
25822942 | 26 | @settitle @value{GDBN} Internals |
c906108c | 27 | |
56caf160 EZ |
28 | @syncodeindex fn cp |
29 | @syncodeindex vr cp | |
30 | ||
c906108c | 31 | @titlepage |
25822942 | 32 | @title @value{GDBN} Internals |
c906108c SS |
33 | @subtitle{A guide to the internals of the GNU debugger} |
34 | @author John Gilmore | |
35 | @author Cygnus Solutions | |
36 | @author Second Edition: | |
37 | @author Stan Shebs | |
38 | @author Cygnus Solutions | |
39 | @page | |
40 | @tex | |
41 | \def\$#1${{#1}} % Kluge: collect RCS revision info without $...$ | |
42 | \xdef\manvers{\$Revision$} % For use in headers, footers too | |
43 | {\parskip=0pt | |
44 | \hfill Cygnus Solutions\par | |
45 | \hfill \manvers\par | |
46 | \hfill \TeX{}info \texinfoversion\par | |
47 | } | |
48 | @end tex | |
49 | ||
50 | @vskip 0pt plus 1filll | |
1e698235 | 51 | Copyright @copyright{} 1990,1991,1992,1993,1994,1996,1998,1999,2000,2001, |
c91d38aa | 52 | 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. |
c906108c | 53 | |
e9c75b65 EZ |
54 | Permission is granted to copy, distribute and/or modify this document |
55 | under the terms of the GNU Free Documentation License, Version 1.1 or | |
2a6585f0 | 56 | any later version published by the Free Software Foundation; with no |
e5249f67 AC |
57 | Invariant Sections, with no Front-Cover Texts, and with no Back-Cover |
58 | Texts. A copy of the license is included in the section entitled ``GNU | |
59 | Free Documentation License''. | |
c906108c SS |
60 | @end titlepage |
61 | ||
449f3b6c | 62 | @contents |
449f3b6c | 63 | |
c906108c SS |
64 | @node Top |
65 | @c Perhaps this should be the title of the document (but only for info, | |
66 | @c not for TeX). Existing GNU manuals seem inconsistent on this point. | |
67 | @top Scope of this Document | |
68 | ||
25822942 DB |
69 | This document documents the internals of the GNU debugger, @value{GDBN}. It |
70 | includes description of @value{GDBN}'s key algorithms and operations, as well | |
71 | as the mechanisms that adapt @value{GDBN} to specific hosts and targets. | |
c906108c SS |
72 | |
73 | @menu | |
74 | * Requirements:: | |
75 | * Overall Structure:: | |
76 | * Algorithms:: | |
77 | * User Interface:: | |
89437448 | 78 | * libgdb:: |
c906108c SS |
79 | * Symbol Handling:: |
80 | * Language Support:: | |
81 | * Host Definition:: | |
82 | * Target Architecture Definition:: | |
123dc839 | 83 | * Target Descriptions:: |
c906108c SS |
84 | * Target Vector Definition:: |
85 | * Native Debugging:: | |
86 | * Support Libraries:: | |
87 | * Coding:: | |
88 | * Porting GDB:: | |
d52fe014 | 89 | * Versions and Branches:: |
55f6ca0f | 90 | * Start of New Year Procedure:: |
8973da3a | 91 | * Releasing GDB:: |
085dd6e6 | 92 | * Testsuite:: |
c906108c | 93 | * Hints:: |
aab4e0ec | 94 | |
bcd7e15f | 95 | * GDB Observers:: @value{GDBN} Currently available observers |
aab4e0ec | 96 | * GNU Free Documentation License:: The license for this documentation |
56caf160 | 97 | * Index:: |
c906108c SS |
98 | @end menu |
99 | ||
100 | @node Requirements | |
101 | ||
102 | @chapter Requirements | |
56caf160 | 103 | @cindex requirements for @value{GDBN} |
c906108c SS |
104 | |
105 | Before diving into the internals, you should understand the formal | |
56caf160 EZ |
106 | requirements and other expectations for @value{GDBN}. Although some |
107 | of these may seem obvious, there have been proposals for @value{GDBN} | |
108 | that have run counter to these requirements. | |
c906108c | 109 | |
56caf160 EZ |
110 | First of all, @value{GDBN} is a debugger. It's not designed to be a |
111 | front panel for embedded systems. It's not a text editor. It's not a | |
112 | shell. It's not a programming environment. | |
c906108c | 113 | |
56caf160 EZ |
114 | @value{GDBN} is an interactive tool. Although a batch mode is |
115 | available, @value{GDBN}'s primary role is to interact with a human | |
116 | programmer. | |
c906108c | 117 | |
56caf160 EZ |
118 | @value{GDBN} should be responsive to the user. A programmer hot on |
119 | the trail of a nasty bug, and operating under a looming deadline, is | |
120 | going to be very impatient of everything, including the response time | |
121 | to debugger commands. | |
c906108c | 122 | |
56caf160 EZ |
123 | @value{GDBN} should be relatively permissive, such as for expressions. |
124 | While the compiler should be picky (or have the option to be made | |
be9c6c35 | 125 | picky), since source code lives for a long time usually, the |
56caf160 EZ |
126 | programmer doing debugging shouldn't be spending time figuring out to |
127 | mollify the debugger. | |
c906108c | 128 | |
56caf160 EZ |
129 | @value{GDBN} will be called upon to deal with really large programs. |
130 | Executable sizes of 50 to 100 megabytes occur regularly, and we've | |
131 | heard reports of programs approaching 1 gigabyte in size. | |
c906108c | 132 | |
56caf160 EZ |
133 | @value{GDBN} should be able to run everywhere. No other debugger is |
134 | available for even half as many configurations as @value{GDBN} | |
135 | supports. | |
c906108c SS |
136 | |
137 | ||
138 | @node Overall Structure | |
139 | ||
140 | @chapter Overall Structure | |
141 | ||
56caf160 EZ |
142 | @value{GDBN} consists of three major subsystems: user interface, |
143 | symbol handling (the @dfn{symbol side}), and target system handling (the | |
144 | @dfn{target side}). | |
c906108c | 145 | |
2e685b93 | 146 | The user interface consists of several actual interfaces, plus |
c906108c SS |
147 | supporting code. |
148 | ||
149 | The symbol side consists of object file readers, debugging info | |
150 | interpreters, symbol table management, source language expression | |
151 | parsing, type and value printing. | |
152 | ||
153 | The target side consists of execution control, stack frame analysis, and | |
154 | physical target manipulation. | |
155 | ||
156 | The target side/symbol side division is not formal, and there are a | |
157 | number of exceptions. For instance, core file support involves symbolic | |
158 | elements (the basic core file reader is in BFD) and target elements (it | |
159 | supplies the contents of memory and the values of registers). Instead, | |
160 | this division is useful for understanding how the minor subsystems | |
161 | should fit together. | |
162 | ||
163 | @section The Symbol Side | |
164 | ||
56caf160 EZ |
165 | The symbolic side of @value{GDBN} can be thought of as ``everything |
166 | you can do in @value{GDBN} without having a live program running''. | |
167 | For instance, you can look at the types of variables, and evaluate | |
168 | many kinds of expressions. | |
c906108c SS |
169 | |
170 | @section The Target Side | |
171 | ||
56caf160 EZ |
172 | The target side of @value{GDBN} is the ``bits and bytes manipulator''. |
173 | Although it may make reference to symbolic info here and there, most | |
174 | of the target side will run with only a stripped executable | |
175 | available---or even no executable at all, in remote debugging cases. | |
c906108c SS |
176 | |
177 | Operations such as disassembly, stack frame crawls, and register | |
178 | display, are able to work with no symbolic info at all. In some cases, | |
25822942 | 179 | such as disassembly, @value{GDBN} will use symbolic info to present addresses |
c906108c SS |
180 | relative to symbols rather than as raw numbers, but it will work either |
181 | way. | |
182 | ||
183 | @section Configurations | |
184 | ||
56caf160 EZ |
185 | @cindex host |
186 | @cindex target | |
25822942 | 187 | @dfn{Host} refers to attributes of the system where @value{GDBN} runs. |
c906108c SS |
188 | @dfn{Target} refers to the system where the program being debugged |
189 | executes. In most cases they are the same machine, in which case a | |
190 | third type of @dfn{Native} attributes come into play. | |
191 | ||
192 | Defines and include files needed to build on the host are host support. | |
193 | Examples are tty support, system defined types, host byte order, host | |
194 | float format. | |
195 | ||
196 | Defines and information needed to handle the target format are target | |
197 | dependent. Examples are the stack frame format, instruction set, | |
198 | breakpoint instruction, registers, and how to set up and tear down the stack | |
199 | to call a function. | |
200 | ||
201 | Information that is only needed when the host and target are the same, | |
202 | is native dependent. One example is Unix child process support; if the | |
203 | host and target are not the same, doing a fork to start the target | |
204 | process is a bad idea. The various macros needed for finding the | |
205 | registers in the @code{upage}, running @code{ptrace}, and such are all | |
206 | in the native-dependent files. | |
207 | ||
208 | Another example of native-dependent code is support for features that | |
209 | are really part of the target environment, but which require | |
210 | @code{#include} files that are only available on the host system. Core | |
211 | file handling and @code{setjmp} handling are two common cases. | |
212 | ||
25822942 | 213 | When you want to make @value{GDBN} work ``native'' on a particular machine, you |
c906108c SS |
214 | have to include all three kinds of information. |
215 | ||
25ab7e6d EZ |
216 | @section Source Tree Structure |
217 | @cindex @value{GDBN} source tree structure | |
218 | ||
219 | The @value{GDBN} source directory has a mostly flat structure---there | |
220 | are only a few subdirectories. A file's name usually gives a hint as | |
221 | to what it does; for example, @file{stabsread.c} reads stabs, | |
7ce59000 | 222 | @file{dwarf2read.c} reads @sc{DWARF 2}, etc. |
25ab7e6d EZ |
223 | |
224 | Files that are related to some common task have names that share | |
225 | common substrings. For example, @file{*-thread.c} files deal with | |
226 | debugging threads on various platforms; @file{*read.c} files deal with | |
227 | reading various kinds of symbol and object files; @file{inf*.c} files | |
228 | deal with direct control of the @dfn{inferior program} (@value{GDBN} | |
229 | parlance for the program being debugged). | |
230 | ||
231 | There are several dozens of files in the @file{*-tdep.c} family. | |
232 | @samp{tdep} stands for @dfn{target-dependent code}---each of these | |
233 | files implements debug support for a specific target architecture | |
234 | (sparc, mips, etc). Usually, only one of these will be used in a | |
235 | specific @value{GDBN} configuration (sometimes two, closely related). | |
236 | ||
237 | Similarly, there are many @file{*-nat.c} files, each one for native | |
238 | debugging on a specific system (e.g., @file{sparc-linux-nat.c} is for | |
239 | native debugging of Sparc machines running the Linux kernel). | |
240 | ||
241 | The few subdirectories of the source tree are: | |
242 | ||
243 | @table @file | |
244 | @item cli | |
245 | Code that implements @dfn{CLI}, the @value{GDBN} Command-Line | |
246 | Interpreter. @xref{User Interface, Command Interpreter}. | |
247 | ||
248 | @item gdbserver | |
249 | Code for the @value{GDBN} remote server. | |
250 | ||
251 | @item gdbtk | |
252 | Code for Insight, the @value{GDBN} TK-based GUI front-end. | |
253 | ||
254 | @item mi | |
255 | The @dfn{GDB/MI}, the @value{GDBN} Machine Interface interpreter. | |
256 | ||
257 | @item signals | |
258 | Target signal translation code. | |
259 | ||
260 | @item tui | |
261 | Code for @dfn{TUI}, the @value{GDBN} Text-mode full-screen User | |
262 | Interface. @xref{User Interface, TUI}. | |
263 | @end table | |
c906108c SS |
264 | |
265 | @node Algorithms | |
266 | ||
267 | @chapter Algorithms | |
56caf160 | 268 | @cindex algorithms |
c906108c | 269 | |
56caf160 EZ |
270 | @value{GDBN} uses a number of debugging-specific algorithms. They are |
271 | often not very complicated, but get lost in the thicket of special | |
272 | cases and real-world issues. This chapter describes the basic | |
273 | algorithms and mentions some of the specific target definitions that | |
274 | they use. | |
c906108c SS |
275 | |
276 | @section Frames | |
277 | ||
56caf160 EZ |
278 | @cindex frame |
279 | @cindex call stack frame | |
280 | A frame is a construct that @value{GDBN} uses to keep track of calling | |
281 | and called functions. | |
c906108c | 282 | |
410dd08e | 283 | @cindex frame, unwind |
c5e30d01 AC |
284 | @value{GDBN}'s frame model, a fresh design, was implemented with the |
285 | need to support @sc{dwarf}'s Call Frame Information in mind. In fact, | |
286 | the term ``unwind'' is taken directly from that specification. | |
287 | Developers wishing to learn more about unwinders, are encouraged to | |
d3e8051b | 288 | read the @sc{dwarf} specification. |
410dd08e JB |
289 | |
290 | @findex frame_register_unwind | |
c5e30d01 AC |
291 | @findex get_frame_register |
292 | @value{GDBN}'s model is that you find a frame's registers by | |
293 | ``unwinding'' them from the next younger frame. That is, | |
294 | @samp{get_frame_register} which returns the value of a register in | |
295 | frame #1 (the next-to-youngest frame), is implemented by calling frame | |
296 | #0's @code{frame_register_unwind} (the youngest frame). But then the | |
297 | obvious question is: how do you access the registers of the youngest | |
298 | frame itself? | |
410dd08e JB |
299 | |
300 | @cindex sentinel frame | |
301 | @findex get_frame_type | |
302 | @vindex SENTINEL_FRAME | |
303 | To answer this question, GDB has the @dfn{sentinel} frame, the | |
304 | ``-1st'' frame. Unwinding registers from the sentinel frame gives you | |
305 | the current values of the youngest real frame's registers. If @var{f} | |
306 | is a sentinel frame, then @code{get_frame_type (@var{f}) == | |
307 | SENTINEL_FRAME}. | |
308 | ||
7d30c22d JB |
309 | @section Prologue Analysis |
310 | ||
311 | @cindex prologue analysis | |
312 | @cindex call frame information | |
313 | @cindex CFI (call frame information) | |
314 | To produce a backtrace and allow the user to manipulate older frames' | |
315 | variables and arguments, @value{GDBN} needs to find the base addresses | |
316 | of older frames, and discover where those frames' registers have been | |
317 | saved. Since a frame's ``callee-saves'' registers get saved by | |
318 | younger frames if and when they're reused, a frame's registers may be | |
319 | scattered unpredictably across younger frames. This means that | |
320 | changing the value of a register-allocated variable in an older frame | |
321 | may actually entail writing to a save slot in some younger frame. | |
322 | ||
323 | Modern versions of GCC emit Dwarf call frame information (``CFI''), | |
324 | which describes how to find frame base addresses and saved registers. | |
325 | But CFI is not always available, so as a fallback @value{GDBN} uses a | |
326 | technique called @dfn{prologue analysis} to find frame sizes and saved | |
327 | registers. A prologue analyzer disassembles the function's machine | |
328 | code starting from its entry point, and looks for instructions that | |
329 | allocate frame space, save the stack pointer in a frame pointer | |
330 | register, save registers, and so on. Obviously, this can't be done | |
b247355e | 331 | accurately in general, but it's tractable to do well enough to be very |
7d30c22d JB |
332 | helpful. Prologue analysis predates the GNU toolchain's support for |
333 | CFI; at one time, prologue analysis was the only mechanism | |
334 | @value{GDBN} used for stack unwinding at all, when the function | |
335 | calling conventions didn't specify a fixed frame layout. | |
336 | ||
337 | In the olden days, function prologues were generated by hand-written, | |
338 | target-specific code in GCC, and treated as opaque and untouchable by | |
339 | optimizers. Looking at this code, it was usually straightforward to | |
340 | write a prologue analyzer for @value{GDBN} that would accurately | |
341 | understand all the prologues GCC would generate. However, over time | |
342 | GCC became more aggressive about instruction scheduling, and began to | |
343 | understand more about the semantics of the prologue instructions | |
344 | themselves; in response, @value{GDBN}'s analyzers became more complex | |
345 | and fragile. Keeping the prologue analyzers working as GCC (and the | |
346 | instruction sets themselves) evolved became a substantial task. | |
347 | ||
348 | @cindex @file{prologue-value.c} | |
349 | @cindex abstract interpretation of function prologues | |
350 | @cindex pseudo-evaluation of function prologues | |
351 | To try to address this problem, the code in @file{prologue-value.h} | |
352 | and @file{prologue-value.c} provides a general framework for writing | |
353 | prologue analyzers that are simpler and more robust than ad-hoc | |
354 | analyzers. When we analyze a prologue using the prologue-value | |
355 | framework, we're really doing ``abstract interpretation'' or | |
356 | ``pseudo-evaluation'': running the function's code in simulation, but | |
357 | using conservative approximations of the values registers and memory | |
358 | would hold when the code actually runs. For example, if our function | |
359 | starts with the instruction: | |
360 | ||
361 | @example | |
362 | addi r1, 42 # add 42 to r1 | |
363 | @end example | |
364 | @noindent | |
365 | we don't know exactly what value will be in @code{r1} after executing | |
366 | this instruction, but we do know it'll be 42 greater than its original | |
367 | value. | |
368 | ||
369 | If we then see an instruction like: | |
370 | ||
371 | @example | |
372 | addi r1, 22 # add 22 to r1 | |
373 | @end example | |
374 | @noindent | |
375 | we still don't know what @code{r1's} value is, but again, we can say | |
376 | it is now 64 greater than its original value. | |
377 | ||
378 | If the next instruction were: | |
379 | ||
380 | @example | |
381 | mov r2, r1 # set r2 to r1's value | |
382 | @end example | |
383 | @noindent | |
384 | then we can say that @code{r2's} value is now the original value of | |
385 | @code{r1} plus 64. | |
386 | ||
387 | It's common for prologues to save registers on the stack, so we'll | |
388 | need to track the values of stack frame slots, as well as the | |
389 | registers. So after an instruction like this: | |
390 | ||
391 | @example | |
392 | mov (fp+4), r2 | |
393 | @end example | |
394 | @noindent | |
395 | then we'd know that the stack slot four bytes above the frame pointer | |
396 | holds the original value of @code{r1} plus 64. | |
397 | ||
398 | And so on. | |
399 | ||
400 | Of course, this can only go so far before it gets unreasonable. If we | |
401 | wanted to be able to say anything about the value of @code{r1} after | |
402 | the instruction: | |
403 | ||
404 | @example | |
405 | xor r1, r3 # exclusive-or r1 and r3, place result in r1 | |
406 | @end example | |
407 | @noindent | |
408 | then things would get pretty complex. But remember, we're just doing | |
409 | a conservative approximation; if exclusive-or instructions aren't | |
410 | relevant to prologues, we can just say @code{r1}'s value is now | |
411 | ``unknown''. We can ignore things that are too complex, if that loss of | |
412 | information is acceptable for our application. | |
413 | ||
414 | So when we say ``conservative approximation'' here, what we mean is an | |
415 | approximation that is either accurate, or marked ``unknown'', but | |
416 | never inaccurate. | |
417 | ||
418 | Using this framework, a prologue analyzer is simply an interpreter for | |
419 | machine code, but one that uses conservative approximations for the | |
420 | contents of registers and memory instead of actual values. Starting | |
421 | from the function's entry point, you simulate instructions up to the | |
422 | current PC, or an instruction that you don't know how to simulate. | |
423 | Now you can examine the state of the registers and stack slots you've | |
424 | kept track of. | |
425 | ||
426 | @itemize @bullet | |
427 | ||
428 | @item | |
429 | To see how large your stack frame is, just check the value of the | |
430 | stack pointer register; if it's the original value of the SP | |
431 | minus a constant, then that constant is the stack frame's size. | |
432 | If the SP's value has been marked as ``unknown'', then that means | |
433 | the prologue has done something too complex for us to track, and | |
434 | we don't know the frame size. | |
435 | ||
436 | @item | |
437 | To see where we've saved the previous frame's registers, we just | |
438 | search the values we've tracked --- stack slots, usually, but | |
439 | registers, too, if you want --- for something equal to the register's | |
440 | original value. If the calling conventions suggest a standard place | |
441 | to save a given register, then we can check there first, but really, | |
442 | anything that will get us back the original value will probably work. | |
443 | @end itemize | |
444 | ||
445 | This does take some work. But prologue analyzers aren't | |
446 | quick-and-simple pattern patching to recognize a few fixed prologue | |
447 | forms any more; they're big, hairy functions. Along with inferior | |
448 | function calls, prologue analysis accounts for a substantial portion | |
449 | of the time needed to stabilize a @value{GDBN} port. So it's | |
450 | worthwhile to look for an approach that will be easier to understand | |
451 | and maintain. In the approach described above: | |
452 | ||
453 | @itemize @bullet | |
454 | ||
455 | @item | |
456 | It's easier to see that the analyzer is correct: you just see | |
b247355e | 457 | whether the analyzer properly (albeit conservatively) simulates |
7d30c22d JB |
458 | the effect of each instruction. |
459 | ||
460 | @item | |
461 | It's easier to extend the analyzer: you can add support for new | |
462 | instructions, and know that you haven't broken anything that | |
463 | wasn't already broken before. | |
464 | ||
465 | @item | |
466 | It's orthogonal: to gather new information, you don't need to | |
467 | complicate the code for each instruction. As long as your domain | |
468 | of conservative values is already detailed enough to tell you | |
469 | what you need, then all the existing instruction simulations are | |
470 | already gathering the right data for you. | |
471 | ||
472 | @end itemize | |
473 | ||
474 | The file @file{prologue-value.h} contains detailed comments explaining | |
475 | the framework and how to use it. | |
476 | ||
477 | ||
c906108c SS |
478 | @section Breakpoint Handling |
479 | ||
56caf160 | 480 | @cindex breakpoints |
c906108c SS |
481 | In general, a breakpoint is a user-designated location in the program |
482 | where the user wants to regain control if program execution ever reaches | |
483 | that location. | |
484 | ||
485 | There are two main ways to implement breakpoints; either as ``hardware'' | |
486 | breakpoints or as ``software'' breakpoints. | |
487 | ||
56caf160 EZ |
488 | @cindex hardware breakpoints |
489 | @cindex program counter | |
c906108c SS |
490 | Hardware breakpoints are sometimes available as a builtin debugging |
491 | features with some chips. Typically these work by having dedicated | |
492 | register into which the breakpoint address may be stored. If the PC | |
56caf160 | 493 | (shorthand for @dfn{program counter}) |
c906108c | 494 | ever matches a value in a breakpoint registers, the CPU raises an |
56caf160 EZ |
495 | exception and reports it to @value{GDBN}. |
496 | ||
497 | Another possibility is when an emulator is in use; many emulators | |
498 | include circuitry that watches the address lines coming out from the | |
499 | processor, and force it to stop if the address matches a breakpoint's | |
500 | address. | |
501 | ||
502 | A third possibility is that the target already has the ability to do | |
503 | breakpoints somehow; for instance, a ROM monitor may do its own | |
504 | software breakpoints. So although these are not literally ``hardware | |
505 | breakpoints'', from @value{GDBN}'s point of view they work the same; | |
50e3ee83 | 506 | @value{GDBN} need not do anything more than set the breakpoint and wait |
56caf160 | 507 | for something to happen. |
c906108c SS |
508 | |
509 | Since they depend on hardware resources, hardware breakpoints may be | |
56caf160 | 510 | limited in number; when the user asks for more, @value{GDBN} will |
9742079a | 511 | start trying to set software breakpoints. (On some architectures, |
937f164b | 512 | notably the 32-bit x86 platforms, @value{GDBN} cannot always know |
9742079a EZ |
513 | whether there's enough hardware resources to insert all the hardware |
514 | breakpoints and watchpoints. On those platforms, @value{GDBN} prints | |
515 | an error message only when the program being debugged is continued.) | |
56caf160 EZ |
516 | |
517 | @cindex software breakpoints | |
518 | Software breakpoints require @value{GDBN} to do somewhat more work. | |
519 | The basic theory is that @value{GDBN} will replace a program | |
520 | instruction with a trap, illegal divide, or some other instruction | |
521 | that will cause an exception, and then when it's encountered, | |
522 | @value{GDBN} will take the exception and stop the program. When the | |
523 | user says to continue, @value{GDBN} will restore the original | |
c906108c SS |
524 | instruction, single-step, re-insert the trap, and continue on. |
525 | ||
526 | Since it literally overwrites the program being tested, the program area | |
be9c6c35 | 527 | must be writable, so this technique won't work on programs in ROM. It |
c906108c | 528 | can also distort the behavior of programs that examine themselves, |
56caf160 | 529 | although such a situation would be highly unusual. |
c906108c SS |
530 | |
531 | Also, the software breakpoint instruction should be the smallest size of | |
532 | instruction, so it doesn't overwrite an instruction that might be a jump | |
533 | target, and cause disaster when the program jumps into the middle of the | |
534 | breakpoint instruction. (Strictly speaking, the breakpoint must be no | |
535 | larger than the smallest interval between instructions that may be jump | |
536 | targets; perhaps there is an architecture where only even-numbered | |
537 | instructions may jumped to.) Note that it's possible for an instruction | |
538 | set not to have any instructions usable for a software breakpoint, | |
539 | although in practice only the ARC has failed to define such an | |
540 | instruction. | |
541 | ||
56caf160 | 542 | @findex BREAKPOINT |
c906108c SS |
543 | The basic definition of the software breakpoint is the macro |
544 | @code{BREAKPOINT}. | |
545 | ||
546 | Basic breakpoint object handling is in @file{breakpoint.c}. However, | |
547 | much of the interesting breakpoint action is in @file{infrun.c}. | |
548 | ||
8181d85f DJ |
549 | @table @code |
550 | @cindex insert or remove software breakpoint | |
551 | @findex target_remove_breakpoint | |
552 | @findex target_insert_breakpoint | |
553 | @item target_remove_breakpoint (@var{bp_tgt}) | |
554 | @itemx target_insert_breakpoint (@var{bp_tgt}) | |
555 | Insert or remove a software breakpoint at address | |
556 | @code{@var{bp_tgt}->placed_address}. Returns zero for success, | |
557 | non-zero for failure. On input, @var{bp_tgt} contains the address of the | |
558 | breakpoint, and is otherwise initialized to zero. The fields of the | |
559 | @code{struct bp_target_info} pointed to by @var{bp_tgt} are updated | |
560 | to contain other information about the breakpoint on output. The field | |
561 | @code{placed_address} may be updated if the breakpoint was placed at a | |
562 | related address; the field @code{shadow_contents} contains the real | |
563 | contents of the bytes where the breakpoint has been inserted, | |
564 | if reading memory would return the breakpoint instead of the | |
565 | underlying memory; the field @code{shadow_len} is the length of | |
566 | memory cached in @code{shadow_contents}, if any; and the field | |
567 | @code{placed_size} is optionally set and used by the target, if | |
568 | it could differ from @code{shadow_len}. | |
569 | ||
570 | For example, the remote target @samp{Z0} packet does not require | |
571 | shadowing memory, so @code{shadow_len} is left at zero. However, | |
572 | the length reported by @code{BREAKPOINT_FROM_PC} is cached in | |
573 | @code{placed_size}, so that a matching @samp{z0} packet can be | |
574 | used to remove the breakpoint. | |
575 | ||
576 | @cindex insert or remove hardware breakpoint | |
577 | @findex target_remove_hw_breakpoint | |
578 | @findex target_insert_hw_breakpoint | |
579 | @item target_remove_hw_breakpoint (@var{bp_tgt}) | |
580 | @itemx target_insert_hw_breakpoint (@var{bp_tgt}) | |
581 | Insert or remove a hardware-assisted breakpoint at address | |
582 | @code{@var{bp_tgt}->placed_address}. Returns zero for success, | |
583 | non-zero for failure. See @code{target_insert_breakpoint} for | |
584 | a description of the @code{struct bp_target_info} pointed to by | |
585 | @var{bp_tgt}; the @code{shadow_contents} and | |
586 | @code{shadow_len} members are not used for hardware breakpoints, | |
587 | but @code{placed_size} may be. | |
588 | @end table | |
589 | ||
c906108c SS |
590 | @section Single Stepping |
591 | ||
592 | @section Signal Handling | |
593 | ||
594 | @section Thread Handling | |
595 | ||
596 | @section Inferior Function Calls | |
597 | ||
598 | @section Longjmp Support | |
599 | ||
56caf160 | 600 | @cindex @code{longjmp} debugging |
25822942 | 601 | @value{GDBN} has support for figuring out that the target is doing a |
c906108c SS |
602 | @code{longjmp} and for stopping at the target of the jump, if we are |
603 | stepping. This is done with a few specialized internal breakpoints, | |
56caf160 EZ |
604 | which are visible in the output of the @samp{maint info breakpoint} |
605 | command. | |
c906108c | 606 | |
56caf160 | 607 | @findex GET_LONGJMP_TARGET |
c906108c SS |
608 | To make this work, you need to define a macro called |
609 | @code{GET_LONGJMP_TARGET}, which will examine the @code{jmp_buf} | |
610 | structure and extract the longjmp target address. Since @code{jmp_buf} | |
611 | is target specific, you will need to define it in the appropriate | |
56caf160 | 612 | @file{tm-@var{target}.h} file. Look in @file{tm-sun4os4.h} and |
c906108c SS |
613 | @file{sparc-tdep.c} for examples of how to do this. |
614 | ||
9742079a EZ |
615 | @section Watchpoints |
616 | @cindex watchpoints | |
617 | ||
618 | Watchpoints are a special kind of breakpoints (@pxref{Algorithms, | |
619 | breakpoints}) which break when data is accessed rather than when some | |
620 | instruction is executed. When you have data which changes without | |
621 | your knowing what code does that, watchpoints are the silver bullet to | |
622 | hunt down and kill such bugs. | |
623 | ||
624 | @cindex hardware watchpoints | |
625 | @cindex software watchpoints | |
626 | Watchpoints can be either hardware-assisted or not; the latter type is | |
627 | known as ``software watchpoints.'' @value{GDBN} always uses | |
628 | hardware-assisted watchpoints if they are available, and falls back on | |
629 | software watchpoints otherwise. Typical situations where @value{GDBN} | |
630 | will use software watchpoints are: | |
631 | ||
632 | @itemize @bullet | |
633 | @item | |
634 | The watched memory region is too large for the underlying hardware | |
635 | watchpoint support. For example, each x86 debug register can watch up | |
636 | to 4 bytes of memory, so trying to watch data structures whose size is | |
637 | more than 16 bytes will cause @value{GDBN} to use software | |
638 | watchpoints. | |
639 | ||
640 | @item | |
641 | The value of the expression to be watched depends on data held in | |
642 | registers (as opposed to memory). | |
643 | ||
644 | @item | |
645 | Too many different watchpoints requested. (On some architectures, | |
646 | this situation is impossible to detect until the debugged program is | |
647 | resumed.) Note that x86 debug registers are used both for hardware | |
648 | breakpoints and for watchpoints, so setting too many hardware | |
649 | breakpoints might cause watchpoint insertion to fail. | |
650 | ||
651 | @item | |
652 | No hardware-assisted watchpoints provided by the target | |
653 | implementation. | |
654 | @end itemize | |
655 | ||
656 | Software watchpoints are very slow, since @value{GDBN} needs to | |
657 | single-step the program being debugged and test the value of the | |
658 | watched expression(s) after each instruction. The rest of this | |
659 | section is mostly irrelevant for software watchpoints. | |
660 | ||
b6b8ece6 EZ |
661 | When the inferior stops, @value{GDBN} tries to establish, among other |
662 | possible reasons, whether it stopped due to a watchpoint being hit. | |
663 | For a data-write watchpoint, it does so by evaluating, for each | |
664 | watchpoint, the expression whose value is being watched, and testing | |
665 | whether the watched value has changed. For data-read and data-access | |
666 | watchpoints, @value{GDBN} needs the target to supply a primitive that | |
667 | returns the address of the data that was accessed or read (see the | |
668 | description of @code{target_stopped_data_address} below): if this | |
669 | primitive returns a valid address, @value{GDBN} infers that a | |
670 | watchpoint triggered if it watches an expression whose evaluation uses | |
671 | that address. | |
672 | ||
9742079a EZ |
673 | @value{GDBN} uses several macros and primitives to support hardware |
674 | watchpoints: | |
675 | ||
676 | @table @code | |
677 | @findex TARGET_HAS_HARDWARE_WATCHPOINTS | |
678 | @item TARGET_HAS_HARDWARE_WATCHPOINTS | |
679 | If defined, the target supports hardware watchpoints. | |
680 | ||
681 | @findex TARGET_CAN_USE_HARDWARE_WATCHPOINT | |
682 | @item TARGET_CAN_USE_HARDWARE_WATCHPOINT (@var{type}, @var{count}, @var{other}) | |
683 | Return the number of hardware watchpoints of type @var{type} that are | |
684 | possible to be set. The value is positive if @var{count} watchpoints | |
685 | of this type can be set, zero if setting watchpoints of this type is | |
686 | not supported, and negative if @var{count} is more than the maximum | |
687 | number of watchpoints of type @var{type} that can be set. @var{other} | |
688 | is non-zero if other types of watchpoints are currently enabled (there | |
689 | are architectures which cannot set watchpoints of different types at | |
690 | the same time). | |
691 | ||
692 | @findex TARGET_REGION_OK_FOR_HW_WATCHPOINT | |
693 | @item TARGET_REGION_OK_FOR_HW_WATCHPOINT (@var{addr}, @var{len}) | |
694 | Return non-zero if hardware watchpoints can be used to watch a region | |
695 | whose address is @var{addr} and whose length in bytes is @var{len}. | |
696 | ||
b6b8ece6 | 697 | @cindex insert or remove hardware watchpoint |
9742079a EZ |
698 | @findex target_insert_watchpoint |
699 | @findex target_remove_watchpoint | |
700 | @item target_insert_watchpoint (@var{addr}, @var{len}, @var{type}) | |
701 | @itemx target_remove_watchpoint (@var{addr}, @var{len}, @var{type}) | |
702 | Insert or remove a hardware watchpoint starting at @var{addr}, for | |
703 | @var{len} bytes. @var{type} is the watchpoint type, one of the | |
704 | possible values of the enumerated data type @code{target_hw_bp_type}, | |
705 | defined by @file{breakpoint.h} as follows: | |
706 | ||
474c8240 | 707 | @smallexample |
9742079a EZ |
708 | enum target_hw_bp_type |
709 | @{ | |
710 | hw_write = 0, /* Common (write) HW watchpoint */ | |
711 | hw_read = 1, /* Read HW watchpoint */ | |
712 | hw_access = 2, /* Access (read or write) HW watchpoint */ | |
713 | hw_execute = 3 /* Execute HW breakpoint */ | |
714 | @}; | |
474c8240 | 715 | @end smallexample |
9742079a EZ |
716 | |
717 | @noindent | |
718 | These two macros should return 0 for success, non-zero for failure. | |
719 | ||
9742079a | 720 | @findex target_stopped_data_address |
ac77d04f JJ |
721 | @item target_stopped_data_address (@var{addr_p}) |
722 | If the inferior has some watchpoint that triggered, place the address | |
723 | associated with the watchpoint at the location pointed to by | |
b6b8ece6 EZ |
724 | @var{addr_p} and return non-zero. Otherwise, return zero. Note that |
725 | this primitive is used by @value{GDBN} only on targets that support | |
726 | data-read or data-access type watchpoints, so targets that have | |
727 | support only for data-write watchpoints need not implement these | |
728 | primitives. | |
9742079a | 729 | |
9742079a EZ |
730 | @findex HAVE_STEPPABLE_WATCHPOINT |
731 | @item HAVE_STEPPABLE_WATCHPOINT | |
732 | If defined to a non-zero value, it is not necessary to disable a | |
733 | watchpoint to step over it. | |
734 | ||
735 | @findex HAVE_NONSTEPPABLE_WATCHPOINT | |
736 | @item HAVE_NONSTEPPABLE_WATCHPOINT | |
737 | If defined to a non-zero value, @value{GDBN} should disable a | |
738 | watchpoint to step the inferior over it. | |
739 | ||
740 | @findex HAVE_CONTINUABLE_WATCHPOINT | |
741 | @item HAVE_CONTINUABLE_WATCHPOINT | |
742 | If defined to a non-zero value, it is possible to continue the | |
743 | inferior after a watchpoint has been hit. | |
744 | ||
745 | @findex CANNOT_STEP_HW_WATCHPOINTS | |
746 | @item CANNOT_STEP_HW_WATCHPOINTS | |
747 | If this is defined to a non-zero value, @value{GDBN} will remove all | |
748 | watchpoints before stepping the inferior. | |
749 | ||
750 | @findex STOPPED_BY_WATCHPOINT | |
751 | @item STOPPED_BY_WATCHPOINT (@var{wait_status}) | |
752 | Return non-zero if stopped by a watchpoint. @var{wait_status} is of | |
753 | the type @code{struct target_waitstatus}, defined by @file{target.h}. | |
b6b8ece6 EZ |
754 | Normally, this macro is defined to invoke the function pointed to by |
755 | the @code{to_stopped_by_watchpoint} member of the structure (of the | |
756 | type @code{target_ops}, defined on @file{target.h}) that describes the | |
757 | target-specific operations; @code{to_stopped_by_watchpoint} ignores | |
758 | the @var{wait_status} argument. | |
759 | ||
760 | @value{GDBN} does not require the non-zero value returned by | |
761 | @code{STOPPED_BY_WATCHPOINT} to be 100% correct, so if a target cannot | |
762 | determine for sure whether the inferior stopped due to a watchpoint, | |
763 | it could return non-zero ``just in case''. | |
9742079a EZ |
764 | @end table |
765 | ||
766 | @subsection x86 Watchpoints | |
767 | @cindex x86 debug registers | |
768 | @cindex watchpoints, on x86 | |
769 | ||
770 | The 32-bit Intel x86 (a.k.a.@: ia32) processors feature special debug | |
771 | registers designed to facilitate debugging. @value{GDBN} provides a | |
772 | generic library of functions that x86-based ports can use to implement | |
773 | support for watchpoints and hardware-assisted breakpoints. This | |
774 | subsection documents the x86 watchpoint facilities in @value{GDBN}. | |
775 | ||
776 | To use the generic x86 watchpoint support, a port should do the | |
777 | following: | |
778 | ||
779 | @itemize @bullet | |
780 | @findex I386_USE_GENERIC_WATCHPOINTS | |
781 | @item | |
782 | Define the macro @code{I386_USE_GENERIC_WATCHPOINTS} somewhere in the | |
783 | target-dependent headers. | |
784 | ||
785 | @item | |
786 | Include the @file{config/i386/nm-i386.h} header file @emph{after} | |
787 | defining @code{I386_USE_GENERIC_WATCHPOINTS}. | |
788 | ||
789 | @item | |
790 | Add @file{i386-nat.o} to the value of the Make variable | |
791 | @code{NATDEPFILES} (@pxref{Native Debugging, NATDEPFILES}) or | |
792 | @code{TDEPFILES} (@pxref{Target Architecture Definition, TDEPFILES}). | |
793 | ||
794 | @item | |
795 | Provide implementations for the @code{I386_DR_LOW_*} macros described | |
796 | below. Typically, each macro should call a target-specific function | |
797 | which does the real work. | |
798 | @end itemize | |
799 | ||
800 | The x86 watchpoint support works by maintaining mirror images of the | |
801 | debug registers. Values are copied between the mirror images and the | |
802 | real debug registers via a set of macros which each target needs to | |
803 | provide: | |
804 | ||
805 | @table @code | |
806 | @findex I386_DR_LOW_SET_CONTROL | |
807 | @item I386_DR_LOW_SET_CONTROL (@var{val}) | |
808 | Set the Debug Control (DR7) register to the value @var{val}. | |
809 | ||
810 | @findex I386_DR_LOW_SET_ADDR | |
811 | @item I386_DR_LOW_SET_ADDR (@var{idx}, @var{addr}) | |
812 | Put the address @var{addr} into the debug register number @var{idx}. | |
813 | ||
814 | @findex I386_DR_LOW_RESET_ADDR | |
815 | @item I386_DR_LOW_RESET_ADDR (@var{idx}) | |
816 | Reset (i.e.@: zero out) the address stored in the debug register | |
817 | number @var{idx}. | |
818 | ||
819 | @findex I386_DR_LOW_GET_STATUS | |
820 | @item I386_DR_LOW_GET_STATUS | |
821 | Return the value of the Debug Status (DR6) register. This value is | |
822 | used immediately after it is returned by | |
823 | @code{I386_DR_LOW_GET_STATUS}, so as to support per-thread status | |
824 | register values. | |
825 | @end table | |
826 | ||
827 | For each one of the 4 debug registers (whose indices are from 0 to 3) | |
828 | that store addresses, a reference count is maintained by @value{GDBN}, | |
829 | to allow sharing of debug registers by several watchpoints. This | |
830 | allows users to define several watchpoints that watch the same | |
831 | expression, but with different conditions and/or commands, without | |
832 | wasting debug registers which are in short supply. @value{GDBN} | |
833 | maintains the reference counts internally, targets don't have to do | |
834 | anything to use this feature. | |
835 | ||
836 | The x86 debug registers can each watch a region that is 1, 2, or 4 | |
837 | bytes long. The ia32 architecture requires that each watched region | |
838 | be appropriately aligned: 2-byte region on 2-byte boundary, 4-byte | |
839 | region on 4-byte boundary. However, the x86 watchpoint support in | |
840 | @value{GDBN} can watch unaligned regions and regions larger than 4 | |
841 | bytes (up to 16 bytes) by allocating several debug registers to watch | |
842 | a single region. This allocation of several registers per a watched | |
843 | region is also done automatically without target code intervention. | |
844 | ||
845 | The generic x86 watchpoint support provides the following API for the | |
846 | @value{GDBN}'s application code: | |
847 | ||
848 | @table @code | |
849 | @findex i386_region_ok_for_watchpoint | |
850 | @item i386_region_ok_for_watchpoint (@var{addr}, @var{len}) | |
851 | The macro @code{TARGET_REGION_OK_FOR_HW_WATCHPOINT} is set to call | |
852 | this function. It counts the number of debug registers required to | |
853 | watch a given region, and returns a non-zero value if that number is | |
854 | less than 4, the number of debug registers available to x86 | |
855 | processors. | |
856 | ||
857 | @findex i386_stopped_data_address | |
ac77d04f JJ |
858 | @item i386_stopped_data_address (@var{addr_p}) |
859 | The target function | |
860 | @code{target_stopped_data_address} is set to call this function. | |
861 | This | |
9742079a EZ |
862 | function examines the breakpoint condition bits in the DR6 Debug |
863 | Status register, as returned by the @code{I386_DR_LOW_GET_STATUS} | |
864 | macro, and returns the address associated with the first bit that is | |
865 | set in DR6. | |
866 | ||
ac77d04f JJ |
867 | @findex i386_stopped_by_watchpoint |
868 | @item i386_stopped_by_watchpoint (void) | |
869 | The macro @code{STOPPED_BY_WATCHPOINT} | |
870 | is set to call this function. The | |
871 | argument passed to @code{STOPPED_BY_WATCHPOINT} is ignored. This | |
872 | function examines the breakpoint condition bits in the DR6 Debug | |
873 | Status register, as returned by the @code{I386_DR_LOW_GET_STATUS} | |
874 | macro, and returns true if any bit is set. Otherwise, false is | |
875 | returned. | |
876 | ||
9742079a EZ |
877 | @findex i386_insert_watchpoint |
878 | @findex i386_remove_watchpoint | |
879 | @item i386_insert_watchpoint (@var{addr}, @var{len}, @var{type}) | |
880 | @itemx i386_remove_watchpoint (@var{addr}, @var{len}, @var{type}) | |
881 | Insert or remove a watchpoint. The macros | |
882 | @code{target_insert_watchpoint} and @code{target_remove_watchpoint} | |
883 | are set to call these functions. @code{i386_insert_watchpoint} first | |
884 | looks for a debug register which is already set to watch the same | |
885 | region for the same access types; if found, it just increments the | |
886 | reference count of that debug register, thus implementing debug | |
887 | register sharing between watchpoints. If no such register is found, | |
937f164b FF |
888 | the function looks for a vacant debug register, sets its mirrored |
889 | value to @var{addr}, sets the mirrored value of DR7 Debug Control | |
9742079a EZ |
890 | register as appropriate for the @var{len} and @var{type} parameters, |
891 | and then passes the new values of the debug register and DR7 to the | |
892 | inferior by calling @code{I386_DR_LOW_SET_ADDR} and | |
893 | @code{I386_DR_LOW_SET_CONTROL}. If more than one debug register is | |
894 | required to cover the given region, the above process is repeated for | |
895 | each debug register. | |
896 | ||
897 | @code{i386_remove_watchpoint} does the opposite: it resets the address | |
937f164b FF |
898 | in the mirrored value of the debug register and its read/write and |
899 | length bits in the mirrored value of DR7, then passes these new | |
9742079a EZ |
900 | values to the inferior via @code{I386_DR_LOW_RESET_ADDR} and |
901 | @code{I386_DR_LOW_SET_CONTROL}. If a register is shared by several | |
902 | watchpoints, each time a @code{i386_remove_watchpoint} is called, it | |
903 | decrements the reference count, and only calls | |
904 | @code{I386_DR_LOW_RESET_ADDR} and @code{I386_DR_LOW_SET_CONTROL} when | |
905 | the count goes to zero. | |
906 | ||
907 | @findex i386_insert_hw_breakpoint | |
908 | @findex i386_remove_hw_breakpoint | |
8181d85f DJ |
909 | @item i386_insert_hw_breakpoint (@var{bp_tgt}) |
910 | @itemx i386_remove_hw_breakpoint (@var{bp_tgt}) | |
9742079a EZ |
911 | These functions insert and remove hardware-assisted breakpoints. The |
912 | macros @code{target_insert_hw_breakpoint} and | |
913 | @code{target_remove_hw_breakpoint} are set to call these functions. | |
8181d85f DJ |
914 | The argument is a @code{struct bp_target_info *}, as described in |
915 | the documentation for @code{target_insert_breakpoint}. | |
9742079a EZ |
916 | These functions work like @code{i386_insert_watchpoint} and |
917 | @code{i386_remove_watchpoint}, respectively, except that they set up | |
918 | the debug registers to watch instruction execution, and each | |
919 | hardware-assisted breakpoint always requires exactly one debug | |
920 | register. | |
921 | ||
922 | @findex i386_stopped_by_hwbp | |
923 | @item i386_stopped_by_hwbp (void) | |
924 | This function returns non-zero if the inferior has some watchpoint or | |
925 | hardware breakpoint that triggered. It works like | |
ac77d04f | 926 | @code{i386_stopped_data_address}, except that it doesn't record the |
9742079a EZ |
927 | address whose watchpoint triggered. |
928 | ||
929 | @findex i386_cleanup_dregs | |
930 | @item i386_cleanup_dregs (void) | |
931 | This function clears all the reference counts, addresses, and control | |
932 | bits in the mirror images of the debug registers. It doesn't affect | |
933 | the actual debug registers in the inferior process. | |
934 | @end table | |
935 | ||
936 | @noindent | |
937 | @strong{Notes:} | |
938 | @enumerate 1 | |
939 | @item | |
940 | x86 processors support setting watchpoints on I/O reads or writes. | |
941 | However, since no target supports this (as of March 2001), and since | |
942 | @code{enum target_hw_bp_type} doesn't even have an enumeration for I/O | |
943 | watchpoints, this feature is not yet available to @value{GDBN} running | |
944 | on x86. | |
945 | ||
946 | @item | |
947 | x86 processors can enable watchpoints locally, for the current task | |
948 | only, or globally, for all the tasks. For each debug register, | |
949 | there's a bit in the DR7 Debug Control register that determines | |
950 | whether the associated address is watched locally or globally. The | |
951 | current implementation of x86 watchpoint support in @value{GDBN} | |
952 | always sets watchpoints to be locally enabled, since global | |
953 | watchpoints might interfere with the underlying OS and are probably | |
954 | unavailable in many platforms. | |
955 | @end enumerate | |
956 | ||
5c95884b MS |
957 | @section Checkpoints |
958 | @cindex checkpoints | |
959 | @cindex restart | |
960 | In the abstract, a checkpoint is a point in the execution history of | |
961 | the program, which the user may wish to return to at some later time. | |
962 | ||
963 | Internally, a checkpoint is a saved copy of the program state, including | |
964 | whatever information is required in order to restore the program to that | |
965 | state at a later time. This can be expected to include the state of | |
966 | registers and memory, and may include external state such as the state | |
967 | of open files and devices. | |
968 | ||
969 | There are a number of ways in which checkpoints may be implemented | |
b247355e | 970 | in gdb, e.g.@: as corefiles, as forked processes, and as some opaque |
5c95884b MS |
971 | method implemented on the target side. |
972 | ||
973 | A corefile can be used to save an image of target memory and register | |
974 | state, which can in principle be restored later --- but corefiles do | |
975 | not typically include information about external entities such as | |
976 | open files. Currently this method is not implemented in gdb. | |
977 | ||
978 | A forked process can save the state of user memory and registers, | |
979 | as well as some subset of external (kernel) state. This method | |
980 | is used to implement checkpoints on Linux, and in principle might | |
981 | be used on other systems. | |
982 | ||
b247355e | 983 | Some targets, e.g.@: simulators, might have their own built-in |
5c95884b MS |
984 | method for saving checkpoints, and gdb might be able to take |
985 | advantage of that capability without necessarily knowing any | |
986 | details of how it is done. | |
987 | ||
988 | ||
bcd7e15f JB |
989 | @section Observing changes in @value{GDBN} internals |
990 | @cindex observer pattern interface | |
991 | @cindex notifications about changes in internals | |
992 | ||
993 | In order to function properly, several modules need to be notified when | |
994 | some changes occur in the @value{GDBN} internals. Traditionally, these | |
995 | modules have relied on several paradigms, the most common ones being | |
996 | hooks and gdb-events. Unfortunately, none of these paradigms was | |
997 | versatile enough to become the standard notification mechanism in | |
998 | @value{GDBN}. The fact that they only supported one ``client'' was also | |
999 | a strong limitation. | |
1000 | ||
1001 | A new paradigm, based on the Observer pattern of the @cite{Design | |
1002 | Patterns} book, has therefore been implemented. The goal was to provide | |
1003 | a new interface overcoming the issues with the notification mechanisms | |
1004 | previously available. This new interface needed to be strongly typed, | |
1005 | easy to extend, and versatile enough to be used as the standard | |
1006 | interface when adding new notifications. | |
1007 | ||
1008 | See @ref{GDB Observers} for a brief description of the observers | |
1009 | currently implemented in GDB. The rationale for the current | |
1010 | implementation is also briefly discussed. | |
1011 | ||
c906108c SS |
1012 | @node User Interface |
1013 | ||
1014 | @chapter User Interface | |
1015 | ||
25822942 | 1016 | @value{GDBN} has several user interfaces. Although the command-line interface |
c906108c SS |
1017 | is the most common and most familiar, there are others. |
1018 | ||
1019 | @section Command Interpreter | |
1020 | ||
56caf160 | 1021 | @cindex command interpreter |
0ee54786 | 1022 | @cindex CLI |
25822942 | 1023 | The command interpreter in @value{GDBN} is fairly simple. It is designed to |
c906108c SS |
1024 | allow for the set of commands to be augmented dynamically, and also |
1025 | has a recursive subcommand capability, where the first argument to | |
1026 | a command may itself direct a lookup on a different command list. | |
1027 | ||
56caf160 EZ |
1028 | For instance, the @samp{set} command just starts a lookup on the |
1029 | @code{setlist} command list, while @samp{set thread} recurses | |
c906108c SS |
1030 | to the @code{set_thread_cmd_list}. |
1031 | ||
56caf160 EZ |
1032 | @findex add_cmd |
1033 | @findex add_com | |
c906108c SS |
1034 | To add commands in general, use @code{add_cmd}. @code{add_com} adds to |
1035 | the main command list, and should be used for those commands. The usual | |
cfeada60 | 1036 | place to add commands is in the @code{_initialize_@var{xyz}} routines at |
9742079a | 1037 | the ends of most source files. |
cfeada60 | 1038 | |
40dd2248 TT |
1039 | @findex add_setshow_cmd |
1040 | @findex add_setshow_cmd_full | |
1041 | To add paired @samp{set} and @samp{show} commands, use | |
1042 | @code{add_setshow_cmd} or @code{add_setshow_cmd_full}. The former is | |
1043 | a slightly simpler interface which is useful when you don't need to | |
1044 | further modify the new command structures, while the latter returns | |
1045 | the new command structures for manipulation. | |
1046 | ||
56caf160 EZ |
1047 | @cindex deprecating commands |
1048 | @findex deprecate_cmd | |
cfeada60 FN |
1049 | Before removing commands from the command set it is a good idea to |
1050 | deprecate them for some time. Use @code{deprecate_cmd} on commands or | |
1051 | aliases to set the deprecated flag. @code{deprecate_cmd} takes a | |
1052 | @code{struct cmd_list_element} as it's first argument. You can use the | |
1053 | return value from @code{add_com} or @code{add_cmd} to deprecate the | |
1054 | command immediately after it is created. | |
1055 | ||
c72e7388 | 1056 | The first time a command is used the user will be warned and offered a |
cfeada60 | 1057 | replacement (if one exists). Note that the replacement string passed to |
d3e8051b | 1058 | @code{deprecate_cmd} should be the full name of the command, i.e., the |
cfeada60 | 1059 | entire string the user should type at the command line. |
c906108c | 1060 | |
0ee54786 EZ |
1061 | @section UI-Independent Output---the @code{ui_out} Functions |
1062 | @c This section is based on the documentation written by Fernando | |
1063 | @c Nasser <fnasser@redhat.com>. | |
1064 | ||
1065 | @cindex @code{ui_out} functions | |
1066 | The @code{ui_out} functions present an abstraction level for the | |
1067 | @value{GDBN} output code. They hide the specifics of different user | |
1068 | interfaces supported by @value{GDBN}, and thus free the programmer | |
1069 | from the need to write several versions of the same code, one each for | |
1070 | every UI, to produce output. | |
1071 | ||
1072 | @subsection Overview and Terminology | |
1073 | ||
1074 | In general, execution of each @value{GDBN} command produces some sort | |
1075 | of output, and can even generate an input request. | |
1076 | ||
1077 | Output can be generated for the following purposes: | |
1078 | ||
1079 | @itemize @bullet | |
1080 | @item | |
1081 | to display a @emph{result} of an operation; | |
1082 | ||
1083 | @item | |
1084 | to convey @emph{info} or produce side-effects of a requested | |
1085 | operation; | |
1086 | ||
1087 | @item | |
1088 | to provide a @emph{notification} of an asynchronous event (including | |
1089 | progress indication of a prolonged asynchronous operation); | |
1090 | ||
1091 | @item | |
1092 | to display @emph{error messages} (including warnings); | |
1093 | ||
1094 | @item | |
1095 | to show @emph{debug data}; | |
1096 | ||
1097 | @item | |
1098 | to @emph{query} or prompt a user for input (a special case). | |
1099 | @end itemize | |
1100 | ||
1101 | @noindent | |
1102 | This section mainly concentrates on how to build result output, | |
1103 | although some of it also applies to other kinds of output. | |
1104 | ||
1105 | Generation of output that displays the results of an operation | |
1106 | involves one or more of the following: | |
1107 | ||
1108 | @itemize @bullet | |
1109 | @item | |
1110 | output of the actual data | |
1111 | ||
1112 | @item | |
1113 | formatting the output as appropriate for console output, to make it | |
1114 | easily readable by humans | |
1115 | ||
1116 | @item | |
1117 | machine oriented formatting--a more terse formatting to allow for easy | |
1118 | parsing by programs which read @value{GDBN}'s output | |
1119 | ||
1120 | @item | |
c72e7388 AC |
1121 | annotation, whose purpose is to help legacy GUIs to identify interesting |
1122 | parts in the output | |
0ee54786 EZ |
1123 | @end itemize |
1124 | ||
1125 | The @code{ui_out} routines take care of the first three aspects. | |
c72e7388 AC |
1126 | Annotations are provided by separate annotation routines. Note that use |
1127 | of annotations for an interface between a GUI and @value{GDBN} is | |
0ee54786 EZ |
1128 | deprecated. |
1129 | ||
c72e7388 AC |
1130 | Output can be in the form of a single item, which we call a @dfn{field}; |
1131 | a @dfn{list} consisting of identical fields; a @dfn{tuple} consisting of | |
1132 | non-identical fields; or a @dfn{table}, which is a tuple consisting of a | |
1133 | header and a body. In a BNF-like form: | |
0ee54786 | 1134 | |
c72e7388 AC |
1135 | @table @code |
1136 | @item <table> @expansion{} | |
1137 | @code{<header> <body>} | |
1138 | @item <header> @expansion{} | |
1139 | @code{@{ <column> @}} | |
1140 | @item <column> @expansion{} | |
1141 | @code{<width> <alignment> <title>} | |
1142 | @item <body> @expansion{} | |
1143 | @code{@{<row>@}} | |
1144 | @end table | |
0ee54786 EZ |
1145 | |
1146 | ||
1147 | @subsection General Conventions | |
1148 | ||
c72e7388 AC |
1149 | Most @code{ui_out} routines are of type @code{void}, the exceptions are |
1150 | @code{ui_out_stream_new} (which returns a pointer to the newly created | |
1151 | object) and the @code{make_cleanup} routines. | |
0ee54786 | 1152 | |
c72e7388 AC |
1153 | The first parameter is always the @code{ui_out} vector object, a pointer |
1154 | to a @code{struct ui_out}. | |
0ee54786 | 1155 | |
c72e7388 AC |
1156 | The @var{format} parameter is like in @code{printf} family of functions. |
1157 | When it is present, there must also be a variable list of arguments | |
1158 | sufficient used to satisfy the @code{%} specifiers in the supplied | |
0ee54786 EZ |
1159 | format. |
1160 | ||
c72e7388 AC |
1161 | When a character string argument is not used in a @code{ui_out} function |
1162 | call, a @code{NULL} pointer has to be supplied instead. | |
0ee54786 EZ |
1163 | |
1164 | ||
c72e7388 | 1165 | @subsection Table, Tuple and List Functions |
0ee54786 EZ |
1166 | |
1167 | @cindex list output functions | |
1168 | @cindex table output functions | |
c72e7388 AC |
1169 | @cindex tuple output functions |
1170 | This section introduces @code{ui_out} routines for building lists, | |
1171 | tuples and tables. The routines to output the actual data items | |
1172 | (fields) are presented in the next section. | |
0ee54786 | 1173 | |
c72e7388 AC |
1174 | To recap: A @dfn{tuple} is a sequence of @dfn{fields}, each field |
1175 | containing information about an object; a @dfn{list} is a sequence of | |
1176 | fields where each field describes an identical object. | |
0ee54786 | 1177 | |
c72e7388 AC |
1178 | Use the @dfn{table} functions when your output consists of a list of |
1179 | rows (tuples) and the console output should include a heading. Use this | |
1180 | even when you are listing just one object but you still want the header. | |
0ee54786 EZ |
1181 | |
1182 | @cindex nesting level in @code{ui_out} functions | |
c72e7388 AC |
1183 | Tables can not be nested. Tuples and lists can be nested up to a |
1184 | maximum of five levels. | |
0ee54786 EZ |
1185 | |
1186 | The overall structure of the table output code is something like this: | |
1187 | ||
474c8240 | 1188 | @smallexample |
0ee54786 EZ |
1189 | ui_out_table_begin |
1190 | ui_out_table_header | |
c72e7388 | 1191 | @dots{} |
0ee54786 | 1192 | ui_out_table_body |
c72e7388 | 1193 | ui_out_tuple_begin |
0ee54786 | 1194 | ui_out_field_* |
c72e7388 AC |
1195 | @dots{} |
1196 | ui_out_tuple_end | |
1197 | @dots{} | |
0ee54786 | 1198 | ui_out_table_end |
474c8240 | 1199 | @end smallexample |
0ee54786 | 1200 | |
c72e7388 | 1201 | Here is the description of table-, tuple- and list-related @code{ui_out} |
0ee54786 EZ |
1202 | functions: |
1203 | ||
c72e7388 AC |
1204 | @deftypefun void ui_out_table_begin (struct ui_out *@var{uiout}, int @var{nbrofcols}, int @var{nr_rows}, const char *@var{tblid}) |
1205 | The function @code{ui_out_table_begin} marks the beginning of the output | |
1206 | of a table. It should always be called before any other @code{ui_out} | |
1207 | function for a given table. @var{nbrofcols} is the number of columns in | |
1208 | the table. @var{nr_rows} is the number of rows in the table. | |
1209 | @var{tblid} is an optional string identifying the table. The string | |
1210 | pointed to by @var{tblid} is copied by the implementation of | |
1211 | @code{ui_out_table_begin}, so the application can free the string if it | |
1212 | was @code{malloc}ed. | |
0ee54786 EZ |
1213 | |
1214 | The companion function @code{ui_out_table_end}, described below, marks | |
1215 | the end of the table's output. | |
1216 | @end deftypefun | |
1217 | ||
c72e7388 AC |
1218 | @deftypefun void ui_out_table_header (struct ui_out *@var{uiout}, int @var{width}, enum ui_align @var{alignment}, const char *@var{colhdr}) |
1219 | @code{ui_out_table_header} provides the header information for a single | |
1220 | table column. You call this function several times, one each for every | |
1221 | column of the table, after @code{ui_out_table_begin}, but before | |
1222 | @code{ui_out_table_body}. | |
0ee54786 EZ |
1223 | |
1224 | The value of @var{width} gives the column width in characters. The | |
1225 | value of @var{alignment} is one of @code{left}, @code{center}, and | |
1226 | @code{right}, and it specifies how to align the header: left-justify, | |
1227 | center, or right-justify it. @var{colhdr} points to a string that | |
1228 | specifies the column header; the implementation copies that string, so | |
c72e7388 AC |
1229 | column header strings in @code{malloc}ed storage can be freed after the |
1230 | call. | |
0ee54786 EZ |
1231 | @end deftypefun |
1232 | ||
1233 | @deftypefun void ui_out_table_body (struct ui_out *@var{uiout}) | |
c72e7388 | 1234 | This function delimits the table header from the table body. |
0ee54786 EZ |
1235 | @end deftypefun |
1236 | ||
1237 | @deftypefun void ui_out_table_end (struct ui_out *@var{uiout}) | |
c72e7388 AC |
1238 | This function signals the end of a table's output. It should be called |
1239 | after the table body has been produced by the list and field output | |
1240 | functions. | |
0ee54786 EZ |
1241 | |
1242 | There should be exactly one call to @code{ui_out_table_end} for each | |
c72e7388 AC |
1243 | call to @code{ui_out_table_begin}, otherwise the @code{ui_out} functions |
1244 | will signal an internal error. | |
0ee54786 EZ |
1245 | @end deftypefun |
1246 | ||
c72e7388 | 1247 | The output of the tuples that represent the table rows must follow the |
0ee54786 | 1248 | call to @code{ui_out_table_body} and precede the call to |
c72e7388 AC |
1249 | @code{ui_out_table_end}. You build a tuple by calling |
1250 | @code{ui_out_tuple_begin} and @code{ui_out_tuple_end}, with suitable | |
0ee54786 EZ |
1251 | calls to functions which actually output fields between them. |
1252 | ||
c72e7388 AC |
1253 | @deftypefun void ui_out_tuple_begin (struct ui_out *@var{uiout}, const char *@var{id}) |
1254 | This function marks the beginning of a tuple output. @var{id} points | |
1255 | to an optional string that identifies the tuple; it is copied by the | |
1256 | implementation, and so strings in @code{malloc}ed storage can be freed | |
1257 | after the call. | |
1258 | @end deftypefun | |
1259 | ||
1260 | @deftypefun void ui_out_tuple_end (struct ui_out *@var{uiout}) | |
1261 | This function signals an end of a tuple output. There should be exactly | |
1262 | one call to @code{ui_out_tuple_end} for each call to | |
1263 | @code{ui_out_tuple_begin}, otherwise an internal @value{GDBN} error will | |
1264 | be signaled. | |
1265 | @end deftypefun | |
1266 | ||
1267 | @deftypefun struct cleanup *make_cleanup_ui_out_tuple_begin_end (struct ui_out *@var{uiout}, const char *@var{id}) | |
1268 | This function first opens the tuple and then establishes a cleanup | |
1269 | (@pxref{Coding, Cleanups}) to close the tuple. It provides a convenient | |
1270 | and correct implementation of the non-portable@footnote{The function | |
b9aa90c9 | 1271 | cast is not portable ISO C.} code sequence: |
c72e7388 AC |
1272 | @smallexample |
1273 | struct cleanup *old_cleanup; | |
1274 | ui_out_tuple_begin (uiout, "..."); | |
1275 | old_cleanup = make_cleanup ((void(*)(void *)) ui_out_tuple_end, | |
1276 | uiout); | |
1277 | @end smallexample | |
1278 | @end deftypefun | |
1279 | ||
1280 | @deftypefun void ui_out_list_begin (struct ui_out *@var{uiout}, const char *@var{id}) | |
1281 | This function marks the beginning of a list output. @var{id} points to | |
1282 | an optional string that identifies the list; it is copied by the | |
1283 | implementation, and so strings in @code{malloc}ed storage can be freed | |
1284 | after the call. | |
0ee54786 EZ |
1285 | @end deftypefun |
1286 | ||
1287 | @deftypefun void ui_out_list_end (struct ui_out *@var{uiout}) | |
c72e7388 AC |
1288 | This function signals an end of a list output. There should be exactly |
1289 | one call to @code{ui_out_list_end} for each call to | |
1290 | @code{ui_out_list_begin}, otherwise an internal @value{GDBN} error will | |
1291 | be signaled. | |
1292 | @end deftypefun | |
1293 | ||
1294 | @deftypefun struct cleanup *make_cleanup_ui_out_list_begin_end (struct ui_out *@var{uiout}, const char *@var{id}) | |
1295 | Similar to @code{make_cleanup_ui_out_tuple_begin_end}, this function | |
1296 | opens a list and then establishes cleanup (@pxref{Coding, Cleanups}) | |
1297 | that will close the list.list. | |
0ee54786 EZ |
1298 | @end deftypefun |
1299 | ||
1300 | @subsection Item Output Functions | |
1301 | ||
1302 | @cindex item output functions | |
1303 | @cindex field output functions | |
1304 | @cindex data output | |
1305 | The functions described below produce output for the actual data | |
1306 | items, or fields, which contain information about the object. | |
1307 | ||
1308 | Choose the appropriate function accordingly to your particular needs. | |
1309 | ||
1310 | @deftypefun void ui_out_field_fmt (struct ui_out *@var{uiout}, char *@var{fldname}, char *@var{format}, ...) | |
1311 | This is the most general output function. It produces the | |
1312 | representation of the data in the variable-length argument list | |
1313 | according to formatting specifications in @var{format}, a | |
1314 | @code{printf}-like format string. The optional argument @var{fldname} | |
1315 | supplies the name of the field. The data items themselves are | |
1316 | supplied as additional arguments after @var{format}. | |
1317 | ||
1318 | This generic function should be used only when it is not possible to | |
1319 | use one of the specialized versions (see below). | |
1320 | @end deftypefun | |
1321 | ||
c72e7388 | 1322 | @deftypefun void ui_out_field_int (struct ui_out *@var{uiout}, const char *@var{fldname}, int @var{value}) |
0ee54786 EZ |
1323 | This function outputs a value of an @code{int} variable. It uses the |
1324 | @code{"%d"} output conversion specification. @var{fldname} specifies | |
1325 | the name of the field. | |
1326 | @end deftypefun | |
8d19fbd2 JJ |
1327 | |
1328 | @deftypefun void ui_out_field_fmt_int (struct ui_out *@var{uiout}, int @var{width}, enum ui_align @var{alignment}, const char *@var{fldname}, int @var{value}) | |
1329 | This function outputs a value of an @code{int} variable. It differs from | |
1330 | @code{ui_out_field_int} in that the caller specifies the desired @var{width} and @var{alignment} of the output. | |
1331 | @var{fldname} specifies | |
1332 | the name of the field. | |
1333 | @end deftypefun | |
0ee54786 | 1334 | |
c72e7388 | 1335 | @deftypefun void ui_out_field_core_addr (struct ui_out *@var{uiout}, const char *@var{fldname}, CORE_ADDR @var{address}) |
0ee54786 EZ |
1336 | This function outputs an address. |
1337 | @end deftypefun | |
1338 | ||
c72e7388 | 1339 | @deftypefun void ui_out_field_string (struct ui_out *@var{uiout}, const char *@var{fldname}, const char *@var{string}) |
0ee54786 EZ |
1340 | This function outputs a string using the @code{"%s"} conversion |
1341 | specification. | |
1342 | @end deftypefun | |
1343 | ||
1344 | Sometimes, there's a need to compose your output piece by piece using | |
1345 | functions that operate on a stream, such as @code{value_print} or | |
1346 | @code{fprintf_symbol_filtered}. These functions accept an argument of | |
1347 | the type @code{struct ui_file *}, a pointer to a @code{ui_file} object | |
1348 | used to store the data stream used for the output. When you use one | |
1349 | of these functions, you need a way to pass their results stored in a | |
1350 | @code{ui_file} object to the @code{ui_out} functions. To this end, | |
1351 | you first create a @code{ui_stream} object by calling | |
1352 | @code{ui_out_stream_new}, pass the @code{stream} member of that | |
1353 | @code{ui_stream} object to @code{value_print} and similar functions, | |
1354 | and finally call @code{ui_out_field_stream} to output the field you | |
1355 | constructed. When the @code{ui_stream} object is no longer needed, | |
1356 | you should destroy it and free its memory by calling | |
1357 | @code{ui_out_stream_delete}. | |
1358 | ||
1359 | @deftypefun struct ui_stream *ui_out_stream_new (struct ui_out *@var{uiout}) | |
1360 | This function creates a new @code{ui_stream} object which uses the | |
1361 | same output methods as the @code{ui_out} object whose pointer is | |
1362 | passed in @var{uiout}. It returns a pointer to the newly created | |
1363 | @code{ui_stream} object. | |
1364 | @end deftypefun | |
1365 | ||
1366 | @deftypefun void ui_out_stream_delete (struct ui_stream *@var{streambuf}) | |
1367 | This functions destroys a @code{ui_stream} object specified by | |
1368 | @var{streambuf}. | |
1369 | @end deftypefun | |
1370 | ||
c72e7388 | 1371 | @deftypefun void ui_out_field_stream (struct ui_out *@var{uiout}, const char *@var{fieldname}, struct ui_stream *@var{streambuf}) |
0ee54786 EZ |
1372 | This function consumes all the data accumulated in |
1373 | @code{streambuf->stream} and outputs it like | |
1374 | @code{ui_out_field_string} does. After a call to | |
1375 | @code{ui_out_field_stream}, the accumulated data no longer exists, but | |
1376 | the stream is still valid and may be used for producing more fields. | |
1377 | @end deftypefun | |
1378 | ||
1379 | @strong{Important:} If there is any chance that your code could bail | |
1380 | out before completing output generation and reaching the point where | |
1381 | @code{ui_out_stream_delete} is called, it is necessary to set up a | |
1382 | cleanup, to avoid leaking memory and other resources. Here's a | |
1383 | skeleton code to do that: | |
1384 | ||
1385 | @smallexample | |
1386 | struct ui_stream *mybuf = ui_out_stream_new (uiout); | |
1387 | struct cleanup *old = make_cleanup (ui_out_stream_delete, mybuf); | |
1388 | ... | |
1389 | do_cleanups (old); | |
1390 | @end smallexample | |
1391 | ||
1392 | If the function already has the old cleanup chain set (for other kinds | |
1393 | of cleanups), you just have to add your cleanup to it: | |
1394 | ||
1395 | @smallexample | |
1396 | mybuf = ui_out_stream_new (uiout); | |
1397 | make_cleanup (ui_out_stream_delete, mybuf); | |
1398 | @end smallexample | |
1399 | ||
1400 | Note that with cleanups in place, you should not call | |
1401 | @code{ui_out_stream_delete} directly, or you would attempt to free the | |
1402 | same buffer twice. | |
1403 | ||
1404 | @subsection Utility Output Functions | |
1405 | ||
c72e7388 | 1406 | @deftypefun void ui_out_field_skip (struct ui_out *@var{uiout}, const char *@var{fldname}) |
0ee54786 EZ |
1407 | This function skips a field in a table. Use it if you have to leave |
1408 | an empty field without disrupting the table alignment. The argument | |
1409 | @var{fldname} specifies a name for the (missing) filed. | |
1410 | @end deftypefun | |
1411 | ||
c72e7388 | 1412 | @deftypefun void ui_out_text (struct ui_out *@var{uiout}, const char *@var{string}) |
0ee54786 EZ |
1413 | This function outputs the text in @var{string} in a way that makes it |
1414 | easy to be read by humans. For example, the console implementation of | |
1415 | this method filters the text through a built-in pager, to prevent it | |
1416 | from scrolling off the visible portion of the screen. | |
1417 | ||
1418 | Use this function for printing relatively long chunks of text around | |
1419 | the actual field data: the text it produces is not aligned according | |
1420 | to the table's format. Use @code{ui_out_field_string} to output a | |
1421 | string field, and use @code{ui_out_message}, described below, to | |
1422 | output short messages. | |
1423 | @end deftypefun | |
1424 | ||
1425 | @deftypefun void ui_out_spaces (struct ui_out *@var{uiout}, int @var{nspaces}) | |
1426 | This function outputs @var{nspaces} spaces. It is handy to align the | |
1427 | text produced by @code{ui_out_text} with the rest of the table or | |
1428 | list. | |
1429 | @end deftypefun | |
1430 | ||
c72e7388 | 1431 | @deftypefun void ui_out_message (struct ui_out *@var{uiout}, int @var{verbosity}, const char *@var{format}, ...) |
0ee54786 EZ |
1432 | This function produces a formatted message, provided that the current |
1433 | verbosity level is at least as large as given by @var{verbosity}. The | |
1434 | current verbosity level is specified by the user with the @samp{set | |
1435 | verbositylevel} command.@footnote{As of this writing (April 2001), | |
1436 | setting verbosity level is not yet implemented, and is always returned | |
1437 | as zero. So calling @code{ui_out_message} with a @var{verbosity} | |
1438 | argument more than zero will cause the message to never be printed.} | |
1439 | @end deftypefun | |
1440 | ||
1441 | @deftypefun void ui_out_wrap_hint (struct ui_out *@var{uiout}, char *@var{indent}) | |
1442 | This function gives the console output filter (a paging filter) a hint | |
1443 | of where to break lines which are too long. Ignored for all other | |
1444 | output consumers. @var{indent}, if non-@code{NULL}, is the string to | |
1445 | be printed to indent the wrapped text on the next line; it must remain | |
1446 | accessible until the next call to @code{ui_out_wrap_hint}, or until an | |
1447 | explicit newline is produced by one of the other functions. If | |
1448 | @var{indent} is @code{NULL}, the wrapped text will not be indented. | |
1449 | @end deftypefun | |
1450 | ||
1451 | @deftypefun void ui_out_flush (struct ui_out *@var{uiout}) | |
1452 | This function flushes whatever output has been accumulated so far, if | |
1453 | the UI buffers output. | |
1454 | @end deftypefun | |
1455 | ||
1456 | ||
1457 | @subsection Examples of Use of @code{ui_out} functions | |
1458 | ||
1459 | @cindex using @code{ui_out} functions | |
1460 | @cindex @code{ui_out} functions, usage examples | |
1461 | This section gives some practical examples of using the @code{ui_out} | |
1462 | functions to generalize the old console-oriented code in | |
1463 | @value{GDBN}. The examples all come from functions defined on the | |
1464 | @file{breakpoints.c} file. | |
1465 | ||
1466 | This example, from the @code{breakpoint_1} function, shows how to | |
1467 | produce a table. | |
1468 | ||
1469 | The original code was: | |
1470 | ||
474c8240 | 1471 | @smallexample |
0ee54786 EZ |
1472 | if (!found_a_breakpoint++) |
1473 | @{ | |
1474 | annotate_breakpoints_headers (); | |
1475 | ||
1476 | annotate_field (0); | |
1477 | printf_filtered ("Num "); | |
1478 | annotate_field (1); | |
1479 | printf_filtered ("Type "); | |
1480 | annotate_field (2); | |
1481 | printf_filtered ("Disp "); | |
1482 | annotate_field (3); | |
1483 | printf_filtered ("Enb "); | |
1484 | if (addressprint) | |
1485 | @{ | |
1486 | annotate_field (4); | |
1487 | printf_filtered ("Address "); | |
1488 | @} | |
1489 | annotate_field (5); | |
1490 | printf_filtered ("What\n"); | |
1491 | ||
1492 | annotate_breakpoints_table (); | |
1493 | @} | |
474c8240 | 1494 | @end smallexample |
0ee54786 EZ |
1495 | |
1496 | Here's the new version: | |
1497 | ||
474c8240 | 1498 | @smallexample |
c72e7388 AC |
1499 | nr_printable_breakpoints = @dots{}; |
1500 | ||
1501 | if (addressprint) | |
1502 | ui_out_table_begin (ui, 6, nr_printable_breakpoints, "BreakpointTable"); | |
1503 | else | |
1504 | ui_out_table_begin (ui, 5, nr_printable_breakpoints, "BreakpointTable"); | |
1505 | ||
1506 | if (nr_printable_breakpoints > 0) | |
1507 | annotate_breakpoints_headers (); | |
1508 | if (nr_printable_breakpoints > 0) | |
1509 | annotate_field (0); | |
1510 | ui_out_table_header (uiout, 3, ui_left, "number", "Num"); /* 1 */ | |
1511 | if (nr_printable_breakpoints > 0) | |
1512 | annotate_field (1); | |
1513 | ui_out_table_header (uiout, 14, ui_left, "type", "Type"); /* 2 */ | |
1514 | if (nr_printable_breakpoints > 0) | |
1515 | annotate_field (2); | |
1516 | ui_out_table_header (uiout, 4, ui_left, "disp", "Disp"); /* 3 */ | |
1517 | if (nr_printable_breakpoints > 0) | |
1518 | annotate_field (3); | |
1519 | ui_out_table_header (uiout, 3, ui_left, "enabled", "Enb"); /* 4 */ | |
1520 | if (addressprint) | |
1521 | @{ | |
1522 | if (nr_printable_breakpoints > 0) | |
1523 | annotate_field (4); | |
1524 | if (TARGET_ADDR_BIT <= 32) | |
1525 | ui_out_table_header (uiout, 10, ui_left, "addr", "Address");/* 5 */ | |
0ee54786 | 1526 | else |
c72e7388 AC |
1527 | ui_out_table_header (uiout, 18, ui_left, "addr", "Address");/* 5 */ |
1528 | @} | |
1529 | if (nr_printable_breakpoints > 0) | |
1530 | annotate_field (5); | |
1531 | ui_out_table_header (uiout, 40, ui_noalign, "what", "What"); /* 6 */ | |
1532 | ui_out_table_body (uiout); | |
1533 | if (nr_printable_breakpoints > 0) | |
1534 | annotate_breakpoints_table (); | |
474c8240 | 1535 | @end smallexample |
0ee54786 EZ |
1536 | |
1537 | This example, from the @code{print_one_breakpoint} function, shows how | |
1538 | to produce the actual data for the table whose structure was defined | |
1539 | in the above example. The original code was: | |
1540 | ||
474c8240 | 1541 | @smallexample |
0ee54786 EZ |
1542 | annotate_record (); |
1543 | annotate_field (0); | |
1544 | printf_filtered ("%-3d ", b->number); | |
1545 | annotate_field (1); | |
1546 | if ((int)b->type > (sizeof(bptypes)/sizeof(bptypes[0])) | |
1547 | || ((int) b->type != bptypes[(int) b->type].type)) | |
1548 | internal_error ("bptypes table does not describe type #%d.", | |
1549 | (int)b->type); | |
1550 | printf_filtered ("%-14s ", bptypes[(int)b->type].description); | |
1551 | annotate_field (2); | |
1552 | printf_filtered ("%-4s ", bpdisps[(int)b->disposition]); | |
1553 | annotate_field (3); | |
1554 | printf_filtered ("%-3c ", bpenables[(int)b->enable]); | |
c72e7388 | 1555 | @dots{} |
474c8240 | 1556 | @end smallexample |
0ee54786 EZ |
1557 | |
1558 | This is the new version: | |
1559 | ||
474c8240 | 1560 | @smallexample |
0ee54786 | 1561 | annotate_record (); |
c72e7388 | 1562 | ui_out_tuple_begin (uiout, "bkpt"); |
0ee54786 EZ |
1563 | annotate_field (0); |
1564 | ui_out_field_int (uiout, "number", b->number); | |
1565 | annotate_field (1); | |
1566 | if (((int) b->type > (sizeof (bptypes) / sizeof (bptypes[0]))) | |
1567 | || ((int) b->type != bptypes[(int) b->type].type)) | |
1568 | internal_error ("bptypes table does not describe type #%d.", | |
1569 | (int) b->type); | |
1570 | ui_out_field_string (uiout, "type", bptypes[(int)b->type].description); | |
1571 | annotate_field (2); | |
1572 | ui_out_field_string (uiout, "disp", bpdisps[(int)b->disposition]); | |
1573 | annotate_field (3); | |
1574 | ui_out_field_fmt (uiout, "enabled", "%c", bpenables[(int)b->enable]); | |
c72e7388 | 1575 | @dots{} |
474c8240 | 1576 | @end smallexample |
0ee54786 EZ |
1577 | |
1578 | This example, also from @code{print_one_breakpoint}, shows how to | |
1579 | produce a complicated output field using the @code{print_expression} | |
1580 | functions which requires a stream to be passed. It also shows how to | |
1581 | automate stream destruction with cleanups. The original code was: | |
1582 | ||
474c8240 | 1583 | @smallexample |
0ee54786 EZ |
1584 | annotate_field (5); |
1585 | print_expression (b->exp, gdb_stdout); | |
474c8240 | 1586 | @end smallexample |
0ee54786 EZ |
1587 | |
1588 | The new version is: | |
1589 | ||
474c8240 | 1590 | @smallexample |
0ee54786 EZ |
1591 | struct ui_stream *stb = ui_out_stream_new (uiout); |
1592 | struct cleanup *old_chain = make_cleanup_ui_out_stream_delete (stb); | |
1593 | ... | |
1594 | annotate_field (5); | |
1595 | print_expression (b->exp, stb->stream); | |
1596 | ui_out_field_stream (uiout, "what", local_stream); | |
474c8240 | 1597 | @end smallexample |
0ee54786 EZ |
1598 | |
1599 | This example, also from @code{print_one_breakpoint}, shows how to use | |
1600 | @code{ui_out_text} and @code{ui_out_field_string}. The original code | |
1601 | was: | |
1602 | ||
474c8240 | 1603 | @smallexample |
0ee54786 EZ |
1604 | annotate_field (5); |
1605 | if (b->dll_pathname == NULL) | |
1606 | printf_filtered ("<any library> "); | |
1607 | else | |
1608 | printf_filtered ("library \"%s\" ", b->dll_pathname); | |
474c8240 | 1609 | @end smallexample |
0ee54786 EZ |
1610 | |
1611 | It became: | |
1612 | ||
474c8240 | 1613 | @smallexample |
0ee54786 EZ |
1614 | annotate_field (5); |
1615 | if (b->dll_pathname == NULL) | |
1616 | @{ | |
1617 | ui_out_field_string (uiout, "what", "<any library>"); | |
1618 | ui_out_spaces (uiout, 1); | |
1619 | @} | |
1620 | else | |
1621 | @{ | |
1622 | ui_out_text (uiout, "library \""); | |
1623 | ui_out_field_string (uiout, "what", b->dll_pathname); | |
1624 | ui_out_text (uiout, "\" "); | |
1625 | @} | |
474c8240 | 1626 | @end smallexample |
0ee54786 EZ |
1627 | |
1628 | The following example from @code{print_one_breakpoint} shows how to | |
1629 | use @code{ui_out_field_int} and @code{ui_out_spaces}. The original | |
1630 | code was: | |
1631 | ||
474c8240 | 1632 | @smallexample |
0ee54786 EZ |
1633 | annotate_field (5); |
1634 | if (b->forked_inferior_pid != 0) | |
1635 | printf_filtered ("process %d ", b->forked_inferior_pid); | |
474c8240 | 1636 | @end smallexample |
0ee54786 EZ |
1637 | |
1638 | It became: | |
1639 | ||
474c8240 | 1640 | @smallexample |
0ee54786 EZ |
1641 | annotate_field (5); |
1642 | if (b->forked_inferior_pid != 0) | |
1643 | @{ | |
1644 | ui_out_text (uiout, "process "); | |
1645 | ui_out_field_int (uiout, "what", b->forked_inferior_pid); | |
1646 | ui_out_spaces (uiout, 1); | |
1647 | @} | |
474c8240 | 1648 | @end smallexample |
0ee54786 EZ |
1649 | |
1650 | Here's an example of using @code{ui_out_field_string}. The original | |
1651 | code was: | |
1652 | ||
474c8240 | 1653 | @smallexample |
0ee54786 EZ |
1654 | annotate_field (5); |
1655 | if (b->exec_pathname != NULL) | |
1656 | printf_filtered ("program \"%s\" ", b->exec_pathname); | |
474c8240 | 1657 | @end smallexample |
0ee54786 EZ |
1658 | |
1659 | It became: | |
1660 | ||
474c8240 | 1661 | @smallexample |
0ee54786 EZ |
1662 | annotate_field (5); |
1663 | if (b->exec_pathname != NULL) | |
1664 | @{ | |
1665 | ui_out_text (uiout, "program \""); | |
1666 | ui_out_field_string (uiout, "what", b->exec_pathname); | |
1667 | ui_out_text (uiout, "\" "); | |
1668 | @} | |
474c8240 | 1669 | @end smallexample |
0ee54786 EZ |
1670 | |
1671 | Finally, here's an example of printing an address. The original code: | |
1672 | ||
474c8240 | 1673 | @smallexample |
0ee54786 EZ |
1674 | annotate_field (4); |
1675 | printf_filtered ("%s ", | |
15a661f3 | 1676 | hex_string_custom ((unsigned long) b->address, 8)); |
474c8240 | 1677 | @end smallexample |
0ee54786 EZ |
1678 | |
1679 | It became: | |
1680 | ||
474c8240 | 1681 | @smallexample |
0ee54786 EZ |
1682 | annotate_field (4); |
1683 | ui_out_field_core_addr (uiout, "Address", b->address); | |
474c8240 | 1684 | @end smallexample |
0ee54786 EZ |
1685 | |
1686 | ||
c906108c SS |
1687 | @section Console Printing |
1688 | ||
1689 | @section TUI | |
1690 | ||
89437448 | 1691 | @node libgdb |
c906108c | 1692 | |
89437448 AC |
1693 | @chapter libgdb |
1694 | ||
1695 | @section libgdb 1.0 | |
1696 | @cindex @code{libgdb} | |
1697 | @code{libgdb} 1.0 was an abortive project of years ago. The theory was | |
1698 | to provide an API to @value{GDBN}'s functionality. | |
1699 | ||
1700 | @section libgdb 2.0 | |
56caf160 | 1701 | @cindex @code{libgdb} |
89437448 AC |
1702 | @code{libgdb} 2.0 is an ongoing effort to update @value{GDBN} so that is |
1703 | better able to support graphical and other environments. | |
1704 | ||
1705 | Since @code{libgdb} development is on-going, its architecture is still | |
1706 | evolving. The following components have so far been identified: | |
1707 | ||
1708 | @itemize @bullet | |
1709 | @item | |
1710 | Observer - @file{gdb-events.h}. | |
1711 | @item | |
1712 | Builder - @file{ui-out.h} | |
1713 | @item | |
1714 | Event Loop - @file{event-loop.h} | |
1715 | @item | |
1716 | Library - @file{gdb.h} | |
1717 | @end itemize | |
1718 | ||
1719 | The model that ties these components together is described below. | |
1720 | ||
1721 | @section The @code{libgdb} Model | |
1722 | ||
1723 | A client of @code{libgdb} interacts with the library in two ways. | |
1724 | ||
1725 | @itemize @bullet | |
1726 | @item | |
1727 | As an observer (using @file{gdb-events}) receiving notifications from | |
1728 | @code{libgdb} of any internal state changes (break point changes, run | |
1729 | state, etc). | |
1730 | @item | |
1731 | As a client querying @code{libgdb} (using the @file{ui-out} builder) to | |
1732 | obtain various status values from @value{GDBN}. | |
1733 | @end itemize | |
1734 | ||
c1468174 | 1735 | Since @code{libgdb} could have multiple clients (e.g., a GUI supporting |
89437448 AC |
1736 | the existing @value{GDBN} CLI), those clients must co-operate when |
1737 | controlling @code{libgdb}. In particular, a client must ensure that | |
1738 | @code{libgdb} is idle (i.e. no other client is using @code{libgdb}) | |
1739 | before responding to a @file{gdb-event} by making a query. | |
1740 | ||
1741 | @section CLI support | |
1742 | ||
1743 | At present @value{GDBN}'s CLI is very much entangled in with the core of | |
1744 | @code{libgdb}. Consequently, a client wishing to include the CLI in | |
1745 | their interface needs to carefully co-ordinate its own and the CLI's | |
1746 | requirements. | |
1747 | ||
1748 | It is suggested that the client set @code{libgdb} up to be bi-modal | |
1749 | (alternate between CLI and client query modes). The notes below sketch | |
1750 | out the theory: | |
1751 | ||
1752 | @itemize @bullet | |
1753 | @item | |
1754 | The client registers itself as an observer of @code{libgdb}. | |
1755 | @item | |
1756 | The client create and install @code{cli-out} builder using its own | |
1757 | versions of the @code{ui-file} @code{gdb_stderr}, @code{gdb_stdtarg} and | |
1758 | @code{gdb_stdout} streams. | |
1759 | @item | |
1760 | The client creates a separate custom @code{ui-out} builder that is only | |
1761 | used while making direct queries to @code{libgdb}. | |
1762 | @end itemize | |
1763 | ||
1764 | When the client receives input intended for the CLI, it simply passes it | |
1765 | along. Since the @code{cli-out} builder is installed by default, all | |
1766 | the CLI output in response to that command is routed (pronounced rooted) | |
1767 | through to the client controlled @code{gdb_stdout} et.@: al.@: streams. | |
1768 | At the same time, the client is kept abreast of internal changes by | |
1769 | virtue of being a @code{libgdb} observer. | |
1770 | ||
1771 | The only restriction on the client is that it must wait until | |
1772 | @code{libgdb} becomes idle before initiating any queries (using the | |
1773 | client's custom builder). | |
1774 | ||
1775 | @section @code{libgdb} components | |
1776 | ||
1777 | @subheading Observer - @file{gdb-events.h} | |
1778 | @file{gdb-events} provides the client with a very raw mechanism that can | |
1779 | be used to implement an observer. At present it only allows for one | |
1780 | observer and that observer must, internally, handle the need to delay | |
1781 | the processing of any event notifications until after @code{libgdb} has | |
1782 | finished the current command. | |
1783 | ||
1784 | @subheading Builder - @file{ui-out.h} | |
1785 | @file{ui-out} provides the infrastructure necessary for a client to | |
1786 | create a builder. That builder is then passed down to @code{libgdb} | |
1787 | when doing any queries. | |
1788 | ||
1789 | @subheading Event Loop - @file{event-loop.h} | |
1790 | @c There could be an entire section on the event-loop | |
1791 | @file{event-loop}, currently non-re-entrant, provides a simple event | |
1792 | loop. A client would need to either plug its self into this loop or, | |
1793 | implement a new event-loop that GDB would use. | |
1794 | ||
1795 | The event-loop will eventually be made re-entrant. This is so that | |
a9f12a31 | 1796 | @value{GDBN} can better handle the problem of some commands blocking |
89437448 AC |
1797 | instead of returning. |
1798 | ||
1799 | @subheading Library - @file{gdb.h} | |
1800 | @file{libgdb} is the most obvious component of this system. It provides | |
1801 | the query interface. Each function is parameterized by a @code{ui-out} | |
1802 | builder. The result of the query is constructed using that builder | |
1803 | before the query function returns. | |
c906108c SS |
1804 | |
1805 | @node Symbol Handling | |
1806 | ||
1807 | @chapter Symbol Handling | |
1808 | ||
25822942 | 1809 | Symbols are a key part of @value{GDBN}'s operation. Symbols include variables, |
c906108c SS |
1810 | functions, and types. |
1811 | ||
1812 | @section Symbol Reading | |
1813 | ||
56caf160 EZ |
1814 | @cindex symbol reading |
1815 | @cindex reading of symbols | |
1816 | @cindex symbol files | |
1817 | @value{GDBN} reads symbols from @dfn{symbol files}. The usual symbol | |
1818 | file is the file containing the program which @value{GDBN} is | |
1819 | debugging. @value{GDBN} can be directed to use a different file for | |
1820 | symbols (with the @samp{symbol-file} command), and it can also read | |
1821 | more symbols via the @samp{add-file} and @samp{load} commands, or while | |
1822 | reading symbols from shared libraries. | |
1823 | ||
1824 | @findex find_sym_fns | |
1825 | Symbol files are initially opened by code in @file{symfile.c} using | |
1826 | the BFD library (@pxref{Support Libraries}). BFD identifies the type | |
1827 | of the file by examining its header. @code{find_sym_fns} then uses | |
1828 | this identification to locate a set of symbol-reading functions. | |
1829 | ||
1830 | @findex add_symtab_fns | |
1831 | @cindex @code{sym_fns} structure | |
1832 | @cindex adding a symbol-reading module | |
1833 | Symbol-reading modules identify themselves to @value{GDBN} by calling | |
c906108c SS |
1834 | @code{add_symtab_fns} during their module initialization. The argument |
1835 | to @code{add_symtab_fns} is a @code{struct sym_fns} which contains the | |
1836 | name (or name prefix) of the symbol format, the length of the prefix, | |
1837 | and pointers to four functions. These functions are called at various | |
56caf160 | 1838 | times to process symbol files whose identification matches the specified |
c906108c SS |
1839 | prefix. |
1840 | ||
1841 | The functions supplied by each module are: | |
1842 | ||
1843 | @table @code | |
1844 | @item @var{xyz}_symfile_init(struct sym_fns *sf) | |
1845 | ||
56caf160 | 1846 | @cindex secondary symbol file |
c906108c SS |
1847 | Called from @code{symbol_file_add} when we are about to read a new |
1848 | symbol file. This function should clean up any internal state (possibly | |
1849 | resulting from half-read previous files, for example) and prepare to | |
56caf160 EZ |
1850 | read a new symbol file. Note that the symbol file which we are reading |
1851 | might be a new ``main'' symbol file, or might be a secondary symbol file | |
c906108c SS |
1852 | whose symbols are being added to the existing symbol table. |
1853 | ||
1854 | The argument to @code{@var{xyz}_symfile_init} is a newly allocated | |
1855 | @code{struct sym_fns} whose @code{bfd} field contains the BFD for the | |
1856 | new symbol file being read. Its @code{private} field has been zeroed, | |
1857 | and can be modified as desired. Typically, a struct of private | |
1858 | information will be @code{malloc}'d, and a pointer to it will be placed | |
1859 | in the @code{private} field. | |
1860 | ||
1861 | There is no result from @code{@var{xyz}_symfile_init}, but it can call | |
1862 | @code{error} if it detects an unavoidable problem. | |
1863 | ||
1864 | @item @var{xyz}_new_init() | |
1865 | ||
1866 | Called from @code{symbol_file_add} when discarding existing symbols. | |
56caf160 EZ |
1867 | This function needs only handle the symbol-reading module's internal |
1868 | state; the symbol table data structures visible to the rest of | |
1869 | @value{GDBN} will be discarded by @code{symbol_file_add}. It has no | |
1870 | arguments and no result. It may be called after | |
1871 | @code{@var{xyz}_symfile_init}, if a new symbol table is being read, or | |
1872 | may be called alone if all symbols are simply being discarded. | |
c906108c SS |
1873 | |
1874 | @item @var{xyz}_symfile_read(struct sym_fns *sf, CORE_ADDR addr, int mainline) | |
1875 | ||
1876 | Called from @code{symbol_file_add} to actually read the symbols from a | |
1877 | symbol-file into a set of psymtabs or symtabs. | |
1878 | ||
56caf160 | 1879 | @code{sf} points to the @code{struct sym_fns} originally passed to |
c906108c SS |
1880 | @code{@var{xyz}_sym_init} for possible initialization. @code{addr} is |
1881 | the offset between the file's specified start address and its true | |
1882 | address in memory. @code{mainline} is 1 if this is the main symbol | |
c1468174 | 1883 | table being read, and 0 if a secondary symbol file (e.g., shared library |
c906108c SS |
1884 | or dynamically loaded file) is being read.@refill |
1885 | @end table | |
1886 | ||
1887 | In addition, if a symbol-reading module creates psymtabs when | |
1888 | @var{xyz}_symfile_read is called, these psymtabs will contain a pointer | |
1889 | to a function @code{@var{xyz}_psymtab_to_symtab}, which can be called | |
25822942 | 1890 | from any point in the @value{GDBN} symbol-handling code. |
c906108c SS |
1891 | |
1892 | @table @code | |
1893 | @item @var{xyz}_psymtab_to_symtab (struct partial_symtab *pst) | |
1894 | ||
56caf160 | 1895 | Called from @code{psymtab_to_symtab} (or the @code{PSYMTAB_TO_SYMTAB} macro) if |
c906108c SS |
1896 | the psymtab has not already been read in and had its @code{pst->symtab} |
1897 | pointer set. The argument is the psymtab to be fleshed-out into a | |
56caf160 EZ |
1898 | symtab. Upon return, @code{pst->readin} should have been set to 1, and |
1899 | @code{pst->symtab} should contain a pointer to the new corresponding symtab, or | |
c906108c SS |
1900 | zero if there were no symbols in that part of the symbol file. |
1901 | @end table | |
1902 | ||
1903 | @section Partial Symbol Tables | |
1904 | ||
56caf160 | 1905 | @value{GDBN} has three types of symbol tables: |
c906108c SS |
1906 | |
1907 | @itemize @bullet | |
56caf160 EZ |
1908 | @cindex full symbol table |
1909 | @cindex symtabs | |
1910 | @item | |
1911 | Full symbol tables (@dfn{symtabs}). These contain the main | |
1912 | information about symbols and addresses. | |
c906108c | 1913 | |
56caf160 EZ |
1914 | @cindex psymtabs |
1915 | @item | |
1916 | Partial symbol tables (@dfn{psymtabs}). These contain enough | |
c906108c SS |
1917 | information to know when to read the corresponding part of the full |
1918 | symbol table. | |
1919 | ||
56caf160 EZ |
1920 | @cindex minimal symbol table |
1921 | @cindex minsymtabs | |
1922 | @item | |
1923 | Minimal symbol tables (@dfn{msymtabs}). These contain information | |
c906108c | 1924 | gleaned from non-debugging symbols. |
c906108c SS |
1925 | @end itemize |
1926 | ||
56caf160 | 1927 | @cindex partial symbol table |
c906108c SS |
1928 | This section describes partial symbol tables. |
1929 | ||
1930 | A psymtab is constructed by doing a very quick pass over an executable | |
1931 | file's debugging information. Small amounts of information are | |
56caf160 | 1932 | extracted---enough to identify which parts of the symbol table will |
c906108c | 1933 | need to be re-read and fully digested later, when the user needs the |
25822942 | 1934 | information. The speed of this pass causes @value{GDBN} to start up very |
c906108c SS |
1935 | quickly. Later, as the detailed rereading occurs, it occurs in small |
1936 | pieces, at various times, and the delay therefrom is mostly invisible to | |
1937 | the user. | |
1938 | @c (@xref{Symbol Reading}.) | |
1939 | ||
1940 | The symbols that show up in a file's psymtab should be, roughly, those | |
1941 | visible to the debugger's user when the program is not running code from | |
1942 | that file. These include external symbols and types, static symbols and | |
56caf160 | 1943 | types, and @code{enum} values declared at file scope. |
c906108c SS |
1944 | |
1945 | The psymtab also contains the range of instruction addresses that the | |
1946 | full symbol table would represent. | |
1947 | ||
56caf160 EZ |
1948 | @cindex finding a symbol |
1949 | @cindex symbol lookup | |
c906108c SS |
1950 | The idea is that there are only two ways for the user (or much of the |
1951 | code in the debugger) to reference a symbol: | |
1952 | ||
1953 | @itemize @bullet | |
56caf160 EZ |
1954 | @findex find_pc_function |
1955 | @findex find_pc_line | |
1956 | @item | |
c1468174 | 1957 | By its address (e.g., execution stops at some address which is inside a |
56caf160 EZ |
1958 | function in this file). The address will be noticed to be in the |
1959 | range of this psymtab, and the full symtab will be read in. | |
1960 | @code{find_pc_function}, @code{find_pc_line}, and other | |
1961 | @code{find_pc_@dots{}} functions handle this. | |
c906108c | 1962 | |
56caf160 EZ |
1963 | @cindex lookup_symbol |
1964 | @item | |
1965 | By its name | |
c1468174 | 1966 | (e.g., the user asks to print a variable, or set a breakpoint on a |
c906108c SS |
1967 | function). Global names and file-scope names will be found in the |
1968 | psymtab, which will cause the symtab to be pulled in. Local names will | |
1969 | have to be qualified by a global name, or a file-scope name, in which | |
1970 | case we will have already read in the symtab as we evaluated the | |
56caf160 | 1971 | qualifier. Or, a local symbol can be referenced when we are ``in'' a |
c906108c SS |
1972 | local scope, in which case the first case applies. @code{lookup_symbol} |
1973 | does most of the work here. | |
c906108c SS |
1974 | @end itemize |
1975 | ||
1976 | The only reason that psymtabs exist is to cause a symtab to be read in | |
1977 | at the right moment. Any symbol that can be elided from a psymtab, | |
1978 | while still causing that to happen, should not appear in it. Since | |
1979 | psymtabs don't have the idea of scope, you can't put local symbols in | |
1980 | them anyway. Psymtabs don't have the idea of the type of a symbol, | |
1981 | either, so types need not appear, unless they will be referenced by | |
1982 | name. | |
1983 | ||
56caf160 EZ |
1984 | It is a bug for @value{GDBN} to behave one way when only a psymtab has |
1985 | been read, and another way if the corresponding symtab has been read | |
1986 | in. Such bugs are typically caused by a psymtab that does not contain | |
1987 | all the visible symbols, or which has the wrong instruction address | |
1988 | ranges. | |
c906108c | 1989 | |
56caf160 | 1990 | The psymtab for a particular section of a symbol file (objfile) could be |
c906108c SS |
1991 | thrown away after the symtab has been read in. The symtab should always |
1992 | be searched before the psymtab, so the psymtab will never be used (in a | |
1993 | bug-free environment). Currently, psymtabs are allocated on an obstack, | |
1994 | and all the psymbols themselves are allocated in a pair of large arrays | |
1995 | on an obstack, so there is little to be gained by trying to free them | |
1996 | unless you want to do a lot more work. | |
1997 | ||
1998 | @section Types | |
1999 | ||
56caf160 | 2000 | @unnumberedsubsec Fundamental Types (e.g., @code{FT_VOID}, @code{FT_BOOLEAN}). |
c906108c | 2001 | |
56caf160 | 2002 | @cindex fundamental types |
25822942 | 2003 | These are the fundamental types that @value{GDBN} uses internally. Fundamental |
c906108c SS |
2004 | types from the various debugging formats (stabs, ELF, etc) are mapped |
2005 | into one of these. They are basically a union of all fundamental types | |
56caf160 EZ |
2006 | that @value{GDBN} knows about for all the languages that @value{GDBN} |
2007 | knows about. | |
c906108c | 2008 | |
56caf160 | 2009 | @unnumberedsubsec Type Codes (e.g., @code{TYPE_CODE_PTR}, @code{TYPE_CODE_ARRAY}). |
c906108c | 2010 | |
56caf160 EZ |
2011 | @cindex type codes |
2012 | Each time @value{GDBN} builds an internal type, it marks it with one | |
2013 | of these types. The type may be a fundamental type, such as | |
2014 | @code{TYPE_CODE_INT}, or a derived type, such as @code{TYPE_CODE_PTR} | |
2015 | which is a pointer to another type. Typically, several @code{FT_*} | |
2016 | types map to one @code{TYPE_CODE_*} type, and are distinguished by | |
2017 | other members of the type struct, such as whether the type is signed | |
2018 | or unsigned, and how many bits it uses. | |
c906108c | 2019 | |
56caf160 | 2020 | @unnumberedsubsec Builtin Types (e.g., @code{builtin_type_void}, @code{builtin_type_char}). |
c906108c SS |
2021 | |
2022 | These are instances of type structs that roughly correspond to | |
56caf160 EZ |
2023 | fundamental types and are created as global types for @value{GDBN} to |
2024 | use for various ugly historical reasons. We eventually want to | |
2025 | eliminate these. Note for example that @code{builtin_type_int} | |
2026 | initialized in @file{gdbtypes.c} is basically the same as a | |
2027 | @code{TYPE_CODE_INT} type that is initialized in @file{c-lang.c} for | |
2028 | an @code{FT_INTEGER} fundamental type. The difference is that the | |
2029 | @code{builtin_type} is not associated with any particular objfile, and | |
2030 | only one instance exists, while @file{c-lang.c} builds as many | |
2031 | @code{TYPE_CODE_INT} types as needed, with each one associated with | |
2032 | some particular objfile. | |
c906108c SS |
2033 | |
2034 | @section Object File Formats | |
56caf160 | 2035 | @cindex object file formats |
c906108c SS |
2036 | |
2037 | @subsection a.out | |
2038 | ||
56caf160 EZ |
2039 | @cindex @code{a.out} format |
2040 | The @code{a.out} format is the original file format for Unix. It | |
2041 | consists of three sections: @code{text}, @code{data}, and @code{bss}, | |
2042 | which are for program code, initialized data, and uninitialized data, | |
2043 | respectively. | |
c906108c | 2044 | |
56caf160 | 2045 | The @code{a.out} format is so simple that it doesn't have any reserved |
c906108c | 2046 | place for debugging information. (Hey, the original Unix hackers used |
56caf160 EZ |
2047 | @samp{adb}, which is a machine-language debugger!) The only debugging |
2048 | format for @code{a.out} is stabs, which is encoded as a set of normal | |
c906108c SS |
2049 | symbols with distinctive attributes. |
2050 | ||
56caf160 | 2051 | The basic @code{a.out} reader is in @file{dbxread.c}. |
c906108c SS |
2052 | |
2053 | @subsection COFF | |
2054 | ||
56caf160 | 2055 | @cindex COFF format |
c906108c SS |
2056 | The COFF format was introduced with System V Release 3 (SVR3) Unix. |
2057 | COFF files may have multiple sections, each prefixed by a header. The | |
2058 | number of sections is limited. | |
2059 | ||
2060 | The COFF specification includes support for debugging. Although this | |
2061 | was a step forward, the debugging information was woefully limited. For | |
2062 | instance, it was not possible to represent code that came from an | |
2063 | included file. | |
2064 | ||
2065 | The COFF reader is in @file{coffread.c}. | |
2066 | ||
2067 | @subsection ECOFF | |
2068 | ||
56caf160 | 2069 | @cindex ECOFF format |
c906108c SS |
2070 | ECOFF is an extended COFF originally introduced for Mips and Alpha |
2071 | workstations. | |
2072 | ||
2073 | The basic ECOFF reader is in @file{mipsread.c}. | |
2074 | ||
2075 | @subsection XCOFF | |
2076 | ||
56caf160 | 2077 | @cindex XCOFF format |
c906108c SS |
2078 | The IBM RS/6000 running AIX uses an object file format called XCOFF. |
2079 | The COFF sections, symbols, and line numbers are used, but debugging | |
56caf160 EZ |
2080 | symbols are @code{dbx}-style stabs whose strings are located in the |
2081 | @code{.debug} section (rather than the string table). For more | |
2082 | information, see @ref{Top,,,stabs,The Stabs Debugging Format}. | |
c906108c SS |
2083 | |
2084 | The shared library scheme has a clean interface for figuring out what | |
2085 | shared libraries are in use, but the catch is that everything which | |
2086 | refers to addresses (symbol tables and breakpoints at least) needs to be | |
2087 | relocated for both shared libraries and the main executable. At least | |
2088 | using the standard mechanism this can only be done once the program has | |
2089 | been run (or the core file has been read). | |
2090 | ||
2091 | @subsection PE | |
2092 | ||
56caf160 EZ |
2093 | @cindex PE-COFF format |
2094 | Windows 95 and NT use the PE (@dfn{Portable Executable}) format for their | |
c906108c SS |
2095 | executables. PE is basically COFF with additional headers. |
2096 | ||
25822942 | 2097 | While BFD includes special PE support, @value{GDBN} needs only the basic |
c906108c SS |
2098 | COFF reader. |
2099 | ||
2100 | @subsection ELF | |
2101 | ||
56caf160 | 2102 | @cindex ELF format |
c906108c SS |
2103 | The ELF format came with System V Release 4 (SVR4) Unix. ELF is similar |
2104 | to COFF in being organized into a number of sections, but it removes | |
2105 | many of COFF's limitations. | |
2106 | ||
2107 | The basic ELF reader is in @file{elfread.c}. | |
2108 | ||
2109 | @subsection SOM | |
2110 | ||
56caf160 | 2111 | @cindex SOM format |
c906108c SS |
2112 | SOM is HP's object file and debug format (not to be confused with IBM's |
2113 | SOM, which is a cross-language ABI). | |
2114 | ||
1a92f856 | 2115 | The SOM reader is in @file{somread.c}. |
c906108c | 2116 | |
c906108c SS |
2117 | @section Debugging File Formats |
2118 | ||
2119 | This section describes characteristics of debugging information that | |
2120 | are independent of the object file format. | |
2121 | ||
2122 | @subsection stabs | |
2123 | ||
56caf160 | 2124 | @cindex stabs debugging info |
c906108c SS |
2125 | @code{stabs} started out as special symbols within the @code{a.out} |
2126 | format. Since then, it has been encapsulated into other file | |
2127 | formats, such as COFF and ELF. | |
2128 | ||
2129 | While @file{dbxread.c} does some of the basic stab processing, | |
2130 | including for encapsulated versions, @file{stabsread.c} does | |
2131 | the real work. | |
2132 | ||
2133 | @subsection COFF | |
2134 | ||
56caf160 | 2135 | @cindex COFF debugging info |
c906108c SS |
2136 | The basic COFF definition includes debugging information. The level |
2137 | of support is minimal and non-extensible, and is not often used. | |
2138 | ||
2139 | @subsection Mips debug (Third Eye) | |
2140 | ||
56caf160 | 2141 | @cindex ECOFF debugging info |
c906108c SS |
2142 | ECOFF includes a definition of a special debug format. |
2143 | ||
2144 | The file @file{mdebugread.c} implements reading for this format. | |
2145 | ||
c906108c SS |
2146 | @subsection DWARF 2 |
2147 | ||
56caf160 | 2148 | @cindex DWARF 2 debugging info |
c906108c SS |
2149 | DWARF 2 is an improved but incompatible version of DWARF 1. |
2150 | ||
2151 | The DWARF 2 reader is in @file{dwarf2read.c}. | |
2152 | ||
2153 | @subsection SOM | |
2154 | ||
56caf160 | 2155 | @cindex SOM debugging info |
c906108c SS |
2156 | Like COFF, the SOM definition includes debugging information. |
2157 | ||
25822942 | 2158 | @section Adding a New Symbol Reader to @value{GDBN} |
c906108c | 2159 | |
56caf160 EZ |
2160 | @cindex adding debugging info reader |
2161 | If you are using an existing object file format (@code{a.out}, COFF, ELF, etc), | |
c906108c SS |
2162 | there is probably little to be done. |
2163 | ||
2164 | If you need to add a new object file format, you must first add it to | |
2165 | BFD. This is beyond the scope of this document. | |
2166 | ||
2167 | You must then arrange for the BFD code to provide access to the | |
25822942 | 2168 | debugging symbols. Generally @value{GDBN} will have to call swapping routines |
c906108c | 2169 | from BFD and a few other BFD internal routines to locate the debugging |
25822942 | 2170 | information. As much as possible, @value{GDBN} should not depend on the BFD |
c906108c SS |
2171 | internal data structures. |
2172 | ||
2173 | For some targets (e.g., COFF), there is a special transfer vector used | |
2174 | to call swapping routines, since the external data structures on various | |
2175 | platforms have different sizes and layouts. Specialized routines that | |
2176 | will only ever be implemented by one object file format may be called | |
2177 | directly. This interface should be described in a file | |
56caf160 | 2178 | @file{bfd/lib@var{xyz}.h}, which is included by @value{GDBN}. |
c906108c | 2179 | |
c91d38aa DJ |
2180 | @section Memory Management for Symbol Files |
2181 | ||
2182 | Most memory associated with a loaded symbol file is stored on | |
2183 | its @code{objfile_obstack}. This includes symbols, types, | |
2184 | namespace data, and other information produced by the symbol readers. | |
2185 | ||
2186 | Because this data lives on the objfile's obstack, it is automatically | |
2187 | released when the objfile is unloaded or reloaded. Therefore one | |
2188 | objfile must not reference symbol or type data from another objfile; | |
2189 | they could be unloaded at different times. | |
2190 | ||
2191 | User convenience variables, et cetera, have associated types. Normally | |
2192 | these types live in the associated objfile. However, when the objfile | |
2193 | is unloaded, those types are deep copied to global memory, so that | |
2194 | the values of the user variables and history items are not lost. | |
2195 | ||
c906108c SS |
2196 | |
2197 | @node Language Support | |
2198 | ||
2199 | @chapter Language Support | |
2200 | ||
56caf160 EZ |
2201 | @cindex language support |
2202 | @value{GDBN}'s language support is mainly driven by the symbol reader, | |
2203 | although it is possible for the user to set the source language | |
2204 | manually. | |
c906108c | 2205 | |
56caf160 EZ |
2206 | @value{GDBN} chooses the source language by looking at the extension |
2207 | of the file recorded in the debug info; @file{.c} means C, @file{.f} | |
2208 | means Fortran, etc. It may also use a special-purpose language | |
2209 | identifier if the debug format supports it, like with DWARF. | |
c906108c | 2210 | |
25822942 | 2211 | @section Adding a Source Language to @value{GDBN} |
c906108c | 2212 | |
56caf160 EZ |
2213 | @cindex adding source language |
2214 | To add other languages to @value{GDBN}'s expression parser, follow the | |
2215 | following steps: | |
c906108c SS |
2216 | |
2217 | @table @emph | |
2218 | @item Create the expression parser. | |
2219 | ||
56caf160 | 2220 | @cindex expression parser |
c906108c | 2221 | This should reside in a file @file{@var{lang}-exp.y}. Routines for |
56caf160 | 2222 | building parsed expressions into a @code{union exp_element} list are in |
c906108c SS |
2223 | @file{parse.c}. |
2224 | ||
56caf160 | 2225 | @cindex language parser |
c906108c SS |
2226 | Since we can't depend upon everyone having Bison, and YACC produces |
2227 | parsers that define a bunch of global names, the following lines | |
56caf160 | 2228 | @strong{must} be included at the top of the YACC parser, to prevent the |
c906108c SS |
2229 | various parsers from defining the same global names: |
2230 | ||
474c8240 | 2231 | @smallexample |
56caf160 EZ |
2232 | #define yyparse @var{lang}_parse |
2233 | #define yylex @var{lang}_lex | |
2234 | #define yyerror @var{lang}_error | |
2235 | #define yylval @var{lang}_lval | |
2236 | #define yychar @var{lang}_char | |
2237 | #define yydebug @var{lang}_debug | |
2238 | #define yypact @var{lang}_pact | |
2239 | #define yyr1 @var{lang}_r1 | |
2240 | #define yyr2 @var{lang}_r2 | |
2241 | #define yydef @var{lang}_def | |
2242 | #define yychk @var{lang}_chk | |
2243 | #define yypgo @var{lang}_pgo | |
2244 | #define yyact @var{lang}_act | |
2245 | #define yyexca @var{lang}_exca | |
2246 | #define yyerrflag @var{lang}_errflag | |
2247 | #define yynerrs @var{lang}_nerrs | |
474c8240 | 2248 | @end smallexample |
c906108c SS |
2249 | |
2250 | At the bottom of your parser, define a @code{struct language_defn} and | |
2251 | initialize it with the right values for your language. Define an | |
2252 | @code{initialize_@var{lang}} routine and have it call | |
25822942 | 2253 | @samp{add_language(@var{lang}_language_defn)} to tell the rest of @value{GDBN} |
c906108c SS |
2254 | that your language exists. You'll need some other supporting variables |
2255 | and functions, which will be used via pointers from your | |
2256 | @code{@var{lang}_language_defn}. See the declaration of @code{struct | |
2257 | language_defn} in @file{language.h}, and the other @file{*-exp.y} files, | |
2258 | for more information. | |
2259 | ||
2260 | @item Add any evaluation routines, if necessary | |
2261 | ||
56caf160 EZ |
2262 | @cindex expression evaluation routines |
2263 | @findex evaluate_subexp | |
2264 | @findex prefixify_subexp | |
2265 | @findex length_of_subexp | |
c906108c SS |
2266 | If you need new opcodes (that represent the operations of the language), |
2267 | add them to the enumerated type in @file{expression.h}. Add support | |
56caf160 EZ |
2268 | code for these operations in the @code{evaluate_subexp} function |
2269 | defined in the file @file{eval.c}. Add cases | |
c906108c | 2270 | for new opcodes in two functions from @file{parse.c}: |
56caf160 | 2271 | @code{prefixify_subexp} and @code{length_of_subexp}. These compute |
c906108c SS |
2272 | the number of @code{exp_element}s that a given operation takes up. |
2273 | ||
2274 | @item Update some existing code | |
2275 | ||
2276 | Add an enumerated identifier for your language to the enumerated type | |
2277 | @code{enum language} in @file{defs.h}. | |
2278 | ||
2279 | Update the routines in @file{language.c} so your language is included. | |
2280 | These routines include type predicates and such, which (in some cases) | |
2281 | are language dependent. If your language does not appear in the switch | |
2282 | statement, an error is reported. | |
2283 | ||
56caf160 | 2284 | @vindex current_language |
c906108c SS |
2285 | Also included in @file{language.c} is the code that updates the variable |
2286 | @code{current_language}, and the routines that translate the | |
2287 | @code{language_@var{lang}} enumerated identifier into a printable | |
2288 | string. | |
2289 | ||
56caf160 | 2290 | @findex _initialize_language |
c906108c SS |
2291 | Update the function @code{_initialize_language} to include your |
2292 | language. This function picks the default language upon startup, so is | |
25822942 | 2293 | dependent upon which languages that @value{GDBN} is built for. |
c906108c | 2294 | |
56caf160 | 2295 | @findex allocate_symtab |
c906108c SS |
2296 | Update @code{allocate_symtab} in @file{symfile.c} and/or symbol-reading |
2297 | code so that the language of each symtab (source file) is set properly. | |
2298 | This is used to determine the language to use at each stack frame level. | |
2299 | Currently, the language is set based upon the extension of the source | |
2300 | file. If the language can be better inferred from the symbol | |
2301 | information, please set the language of the symtab in the symbol-reading | |
2302 | code. | |
2303 | ||
56caf160 EZ |
2304 | @findex print_subexp |
2305 | @findex op_print_tab | |
2306 | Add helper code to @code{print_subexp} (in @file{expprint.c}) to handle any new | |
c906108c SS |
2307 | expression opcodes you have added to @file{expression.h}. Also, add the |
2308 | printed representations of your operators to @code{op_print_tab}. | |
2309 | ||
2310 | @item Add a place of call | |
2311 | ||
56caf160 | 2312 | @findex parse_exp_1 |
c906108c | 2313 | Add a call to @code{@var{lang}_parse()} and @code{@var{lang}_error} in |
56caf160 | 2314 | @code{parse_exp_1} (defined in @file{parse.c}). |
c906108c SS |
2315 | |
2316 | @item Use macros to trim code | |
2317 | ||
56caf160 | 2318 | @cindex trimming language-dependent code |
25822942 DB |
2319 | The user has the option of building @value{GDBN} for some or all of the |
2320 | languages. If the user decides to build @value{GDBN} for the language | |
c906108c SS |
2321 | @var{lang}, then every file dependent on @file{language.h} will have the |
2322 | macro @code{_LANG_@var{lang}} defined in it. Use @code{#ifdef}s to | |
2323 | leave out large routines that the user won't need if he or she is not | |
2324 | using your language. | |
2325 | ||
25822942 | 2326 | Note that you do not need to do this in your YACC parser, since if @value{GDBN} |
c906108c | 2327 | is not build for @var{lang}, then @file{@var{lang}-exp.tab.o} (the |
25822942 | 2328 | compiled form of your parser) is not linked into @value{GDBN} at all. |
c906108c | 2329 | |
56caf160 EZ |
2330 | See the file @file{configure.in} for how @value{GDBN} is configured |
2331 | for different languages. | |
c906108c SS |
2332 | |
2333 | @item Edit @file{Makefile.in} | |
2334 | ||
2335 | Add dependencies in @file{Makefile.in}. Make sure you update the macro | |
2336 | variables such as @code{HFILES} and @code{OBJS}, otherwise your code may | |
2337 | not get linked in, or, worse yet, it may not get @code{tar}red into the | |
2338 | distribution! | |
c906108c SS |
2339 | @end table |
2340 | ||
2341 | ||
2342 | @node Host Definition | |
2343 | ||
2344 | @chapter Host Definition | |
2345 | ||
56caf160 | 2346 | With the advent of Autoconf, it's rarely necessary to have host |
7fd60527 AC |
2347 | definition machinery anymore. The following information is provided, |
2348 | mainly, as an historical reference. | |
c906108c SS |
2349 | |
2350 | @section Adding a New Host | |
2351 | ||
56caf160 EZ |
2352 | @cindex adding a new host |
2353 | @cindex host, adding | |
7fd60527 AC |
2354 | @value{GDBN}'s host configuration support normally happens via Autoconf. |
2355 | New host-specific definitions should not be needed. Older hosts | |
2356 | @value{GDBN} still use the host-specific definitions and files listed | |
2357 | below, but these mostly exist for historical reasons, and will | |
56caf160 | 2358 | eventually disappear. |
c906108c | 2359 | |
c906108c | 2360 | @table @file |
c906108c | 2361 | @item gdb/config/@var{arch}/@var{xyz}.mh |
7fd60527 AC |
2362 | This file once contained both host and native configuration information |
2363 | (@pxref{Native Debugging}) for the machine @var{xyz}. The host | |
2364 | configuration information is now handed by Autoconf. | |
2365 | ||
2366 | Host configuration information included a definition of | |
2367 | @code{XM_FILE=xm-@var{xyz}.h} and possibly definitions for @code{CC}, | |
7708fa01 AC |
2368 | @code{SYSV_DEFINE}, @code{XM_CFLAGS}, @code{XM_ADD_FILES}, |
2369 | @code{XM_CLIBS}, @code{XM_CDEPS}, etc.; see @file{Makefile.in}. | |
c906108c | 2370 | |
7fd60527 AC |
2371 | New host only configurations do not need this file. |
2372 | ||
c906108c | 2373 | @item gdb/config/@var{arch}/xm-@var{xyz}.h |
7fd60527 AC |
2374 | This file once contained definitions and includes required when hosting |
2375 | gdb on machine @var{xyz}. Those definitions and includes are now | |
2376 | handled by Autoconf. | |
2377 | ||
2378 | New host and native configurations do not need this file. | |
2379 | ||
2380 | @emph{Maintainer's note: Some hosts continue to use the @file{xm-xyz.h} | |
2381 | file to define the macros @var{HOST_FLOAT_FORMAT}, | |
2382 | @var{HOST_DOUBLE_FORMAT} and @var{HOST_LONG_DOUBLE_FORMAT}. That code | |
2383 | also needs to be replaced with either an Autoconf or run-time test.} | |
c906108c | 2384 | |
c906108c SS |
2385 | @end table |
2386 | ||
2387 | @subheading Generic Host Support Files | |
2388 | ||
56caf160 | 2389 | @cindex generic host support |
c906108c SS |
2390 | There are some ``generic'' versions of routines that can be used by |
2391 | various systems. These can be customized in various ways by macros | |
2392 | defined in your @file{xm-@var{xyz}.h} file. If these routines work for | |
2393 | the @var{xyz} host, you can just include the generic file's name (with | |
2394 | @samp{.o}, not @samp{.c}) in @code{XDEPFILES}. | |
2395 | ||
2396 | Otherwise, if your machine needs custom support routines, you will need | |
2397 | to write routines that perform the same functions as the generic file. | |
2398 | Put them into @code{@var{xyz}-xdep.c}, and put @code{@var{xyz}-xdep.o} | |
2399 | into @code{XDEPFILES}. | |
2400 | ||
2401 | @table @file | |
56caf160 EZ |
2402 | @cindex remote debugging support |
2403 | @cindex serial line support | |
c906108c SS |
2404 | @item ser-unix.c |
2405 | This contains serial line support for Unix systems. This is always | |
2406 | included, via the makefile variable @code{SER_HARDWIRE}; override this | |
2407 | variable in the @file{.mh} file to avoid it. | |
2408 | ||
2409 | @item ser-go32.c | |
2410 | This contains serial line support for 32-bit programs running under DOS, | |
56caf160 | 2411 | using the DJGPP (a.k.a.@: GO32) execution environment. |
c906108c | 2412 | |
56caf160 | 2413 | @cindex TCP remote support |
c906108c SS |
2414 | @item ser-tcp.c |
2415 | This contains generic TCP support using sockets. | |
c906108c SS |
2416 | @end table |
2417 | ||
2418 | @section Host Conditionals | |
2419 | ||
56caf160 EZ |
2420 | When @value{GDBN} is configured and compiled, various macros are |
2421 | defined or left undefined, to control compilation based on the | |
2422 | attributes of the host system. These macros and their meanings (or if | |
2423 | the meaning is not documented here, then one of the source files where | |
2424 | they are used is indicated) are: | |
c906108c | 2425 | |
56caf160 | 2426 | @ftable @code |
25822942 | 2427 | @item @value{GDBN}INIT_FILENAME |
56caf160 EZ |
2428 | The default name of @value{GDBN}'s initialization file (normally |
2429 | @file{.gdbinit}). | |
c906108c | 2430 | |
cce74817 JM |
2431 | @item NO_STD_REGS |
2432 | This macro is deprecated. | |
2433 | ||
c906108c SS |
2434 | @item SIGWINCH_HANDLER |
2435 | If your host defines @code{SIGWINCH}, you can define this to be the name | |
2436 | of a function to be called if @code{SIGWINCH} is received. | |
2437 | ||
2438 | @item SIGWINCH_HANDLER_BODY | |
2439 | Define this to expand into code that will define the function named by | |
2440 | the expansion of @code{SIGWINCH_HANDLER}. | |
2441 | ||
2442 | @item ALIGN_STACK_ON_STARTUP | |
56caf160 | 2443 | @cindex stack alignment |
c906108c SS |
2444 | Define this if your system is of a sort that will crash in |
2445 | @code{tgetent} if the stack happens not to be longword-aligned when | |
2446 | @code{main} is called. This is a rare situation, but is known to occur | |
2447 | on several different types of systems. | |
2448 | ||
2449 | @item CRLF_SOURCE_FILES | |
56caf160 | 2450 | @cindex DOS text files |
c906108c SS |
2451 | Define this if host files use @code{\r\n} rather than @code{\n} as a |
2452 | line terminator. This will cause source file listings to omit @code{\r} | |
56caf160 EZ |
2453 | characters when printing and it will allow @code{\r\n} line endings of files |
2454 | which are ``sourced'' by gdb. It must be possible to open files in binary | |
c906108c SS |
2455 | mode using @code{O_BINARY} or, for fopen, @code{"rb"}. |
2456 | ||
2457 | @item DEFAULT_PROMPT | |
56caf160 | 2458 | @cindex prompt |
c906108c SS |
2459 | The default value of the prompt string (normally @code{"(gdb) "}). |
2460 | ||
2461 | @item DEV_TTY | |
56caf160 | 2462 | @cindex terminal device |
c906108c SS |
2463 | The name of the generic TTY device, defaults to @code{"/dev/tty"}. |
2464 | ||
c906108c SS |
2465 | @item FOPEN_RB |
2466 | Define this if binary files are opened the same way as text files. | |
2467 | ||
c906108c | 2468 | @item HAVE_MMAP |
56caf160 | 2469 | @findex mmap |
c906108c SS |
2470 | In some cases, use the system call @code{mmap} for reading symbol |
2471 | tables. For some machines this allows for sharing and quick updates. | |
2472 | ||
c906108c SS |
2473 | @item HAVE_TERMIO |
2474 | Define this if the host system has @code{termio.h}. | |
2475 | ||
c906108c | 2476 | @item INT_MAX |
9742079a EZ |
2477 | @itemx INT_MIN |
2478 | @itemx LONG_MAX | |
2479 | @itemx UINT_MAX | |
2480 | @itemx ULONG_MAX | |
c906108c SS |
2481 | Values for host-side constants. |
2482 | ||
2483 | @item ISATTY | |
2484 | Substitute for isatty, if not available. | |
2485 | ||
2486 | @item LONGEST | |
2487 | This is the longest integer type available on the host. If not defined, | |
2488 | it will default to @code{long long} or @code{long}, depending on | |
2489 | @code{CC_HAS_LONG_LONG}. | |
2490 | ||
2491 | @item CC_HAS_LONG_LONG | |
56caf160 EZ |
2492 | @cindex @code{long long} data type |
2493 | Define this if the host C compiler supports @code{long long}. This is set | |
2494 | by the @code{configure} script. | |
c906108c SS |
2495 | |
2496 | @item PRINTF_HAS_LONG_LONG | |
2497 | Define this if the host can handle printing of long long integers via | |
56caf160 EZ |
2498 | the printf format conversion specifier @code{ll}. This is set by the |
2499 | @code{configure} script. | |
c906108c SS |
2500 | |
2501 | @item HAVE_LONG_DOUBLE | |
56caf160 EZ |
2502 | Define this if the host C compiler supports @code{long double}. This is |
2503 | set by the @code{configure} script. | |
c906108c SS |
2504 | |
2505 | @item PRINTF_HAS_LONG_DOUBLE | |
2506 | Define this if the host can handle printing of long double float-point | |
56caf160 EZ |
2507 | numbers via the printf format conversion specifier @code{Lg}. This is |
2508 | set by the @code{configure} script. | |
c906108c SS |
2509 | |
2510 | @item SCANF_HAS_LONG_DOUBLE | |
2511 | Define this if the host can handle the parsing of long double | |
56caf160 EZ |
2512 | float-point numbers via the scanf format conversion specifier |
2513 | @code{Lg}. This is set by the @code{configure} script. | |
c906108c SS |
2514 | |
2515 | @item LSEEK_NOT_LINEAR | |
2516 | Define this if @code{lseek (n)} does not necessarily move to byte number | |
2517 | @code{n} in the file. This is only used when reading source files. It | |
2518 | is normally faster to define @code{CRLF_SOURCE_FILES} when possible. | |
2519 | ||
2520 | @item L_SET | |
56caf160 EZ |
2521 | This macro is used as the argument to @code{lseek} (or, most commonly, |
2522 | @code{bfd_seek}). FIXME, should be replaced by SEEK_SET instead, | |
2523 | which is the POSIX equivalent. | |
c906108c | 2524 | |
c906108c SS |
2525 | @item NORETURN |
2526 | If defined, this should be one or more tokens, such as @code{volatile}, | |
2527 | that can be used in both the declaration and definition of functions to | |
2528 | indicate that they never return. The default is already set correctly | |
2529 | if compiling with GCC. This will almost never need to be defined. | |
2530 | ||
2531 | @item ATTR_NORETURN | |
2532 | If defined, this should be one or more tokens, such as | |
2533 | @code{__attribute__ ((noreturn))}, that can be used in the declarations | |
2534 | of functions to indicate that they never return. The default is already | |
2535 | set correctly if compiling with GCC. This will almost never need to be | |
2536 | defined. | |
2537 | ||
c906108c | 2538 | @item SEEK_CUR |
9742079a | 2539 | @itemx SEEK_SET |
56caf160 | 2540 | Define these to appropriate value for the system @code{lseek}, if not already |
c906108c SS |
2541 | defined. |
2542 | ||
2543 | @item STOP_SIGNAL | |
56caf160 EZ |
2544 | This is the signal for stopping @value{GDBN}. Defaults to |
2545 | @code{SIGTSTP}. (Only redefined for the Convex.) | |
c906108c | 2546 | |
c906108c SS |
2547 | @item USG |
2548 | Means that System V (prior to SVR4) include files are in use. (FIXME: | |
7ca9f392 AC |
2549 | This symbol is abused in @file{infrun.c}, @file{regex.c}, and |
2550 | @file{utils.c} for other things, at the moment.) | |
c906108c SS |
2551 | |
2552 | @item lint | |
56caf160 | 2553 | Define this to help placate @code{lint} in some situations. |
c906108c SS |
2554 | |
2555 | @item volatile | |
2556 | Define this to override the defaults of @code{__volatile__} or | |
2557 | @code{/**/}. | |
56caf160 | 2558 | @end ftable |
c906108c SS |
2559 | |
2560 | ||
2561 | @node Target Architecture Definition | |
2562 | ||
2563 | @chapter Target Architecture Definition | |
2564 | ||
56caf160 EZ |
2565 | @cindex target architecture definition |
2566 | @value{GDBN}'s target architecture defines what sort of | |
2567 | machine-language programs @value{GDBN} can work with, and how it works | |
2568 | with them. | |
c906108c | 2569 | |
af6c57ea AC |
2570 | The target architecture object is implemented as the C structure |
2571 | @code{struct gdbarch *}. The structure, and its methods, are generated | |
93c2c750 | 2572 | using the Bourne shell script @file{gdbarch.sh}. |
c906108c | 2573 | |
70f80edf JT |
2574 | @section Operating System ABI Variant Handling |
2575 | @cindex OS ABI variants | |
2576 | ||
2577 | @value{GDBN} provides a mechanism for handling variations in OS | |
2578 | ABIs. An OS ABI variant may have influence over any number of | |
2579 | variables in the target architecture definition. There are two major | |
2580 | components in the OS ABI mechanism: sniffers and handlers. | |
2581 | ||
2582 | A @dfn{sniffer} examines a file matching a BFD architecture/flavour pair | |
2583 | (the architecture may be wildcarded) in an attempt to determine the | |
2584 | OS ABI of that file. Sniffers with a wildcarded architecture are considered | |
2585 | to be @dfn{generic}, while sniffers for a specific architecture are | |
2586 | considered to be @dfn{specific}. A match from a specific sniffer | |
2587 | overrides a match from a generic sniffer. Multiple sniffers for an | |
2588 | architecture/flavour may exist, in order to differentiate between two | |
2589 | different operating systems which use the same basic file format. The | |
2590 | OS ABI framework provides a generic sniffer for ELF-format files which | |
2591 | examines the @code{EI_OSABI} field of the ELF header, as well as note | |
2592 | sections known to be used by several operating systems. | |
2593 | ||
2594 | @cindex fine-tuning @code{gdbarch} structure | |
2595 | A @dfn{handler} is used to fine-tune the @code{gdbarch} structure for the | |
2596 | selected OS ABI. There may be only one handler for a given OS ABI | |
2597 | for each BFD architecture. | |
2598 | ||
f4b3909f | 2599 | The following OS ABI variants are defined in @file{defs.h}: |
70f80edf JT |
2600 | |
2601 | @table @code | |
2602 | ||
f4b3909f EZ |
2603 | @findex GDB_OSABI_UNINITIALIZED |
2604 | @item GDB_OSABI_UNINITIALIZED | |
2605 | Used for struct gdbarch_info if ABI is still uninitialized. | |
2606 | ||
70f80edf JT |
2607 | @findex GDB_OSABI_UNKNOWN |
2608 | @item GDB_OSABI_UNKNOWN | |
2609 | The ABI of the inferior is unknown. The default @code{gdbarch} | |
2610 | settings for the architecture will be used. | |
2611 | ||
2612 | @findex GDB_OSABI_SVR4 | |
2613 | @item GDB_OSABI_SVR4 | |
f4b3909f | 2614 | UNIX System V Release 4. |
70f80edf JT |
2615 | |
2616 | @findex GDB_OSABI_HURD | |
2617 | @item GDB_OSABI_HURD | |
f4b3909f | 2618 | GNU using the Hurd kernel. |
70f80edf JT |
2619 | |
2620 | @findex GDB_OSABI_SOLARIS | |
2621 | @item GDB_OSABI_SOLARIS | |
f4b3909f | 2622 | Sun Solaris. |
70f80edf JT |
2623 | |
2624 | @findex GDB_OSABI_OSF1 | |
2625 | @item GDB_OSABI_OSF1 | |
f4b3909f | 2626 | OSF/1, including Digital UNIX and Compaq Tru64 UNIX. |
70f80edf JT |
2627 | |
2628 | @findex GDB_OSABI_LINUX | |
2629 | @item GDB_OSABI_LINUX | |
f4b3909f | 2630 | GNU using the Linux kernel. |
70f80edf JT |
2631 | |
2632 | @findex GDB_OSABI_FREEBSD_AOUT | |
2633 | @item GDB_OSABI_FREEBSD_AOUT | |
f4b3909f | 2634 | FreeBSD using the @code{a.out} executable format. |
70f80edf JT |
2635 | |
2636 | @findex GDB_OSABI_FREEBSD_ELF | |
2637 | @item GDB_OSABI_FREEBSD_ELF | |
f4b3909f | 2638 | FreeBSD using the ELF executable format. |
70f80edf JT |
2639 | |
2640 | @findex GDB_OSABI_NETBSD_AOUT | |
2641 | @item GDB_OSABI_NETBSD_AOUT | |
f4b3909f | 2642 | NetBSD using the @code{a.out} executable format. |
70f80edf JT |
2643 | |
2644 | @findex GDB_OSABI_NETBSD_ELF | |
2645 | @item GDB_OSABI_NETBSD_ELF | |
f4b3909f EZ |
2646 | NetBSD using the ELF executable format. |
2647 | ||
2648 | @findex GDB_OSABI_OPENBSD_ELF | |
2649 | @item GDB_OSABI_OPENBSD_ELF | |
2650 | OpenBSD using the ELF executable format. | |
70f80edf JT |
2651 | |
2652 | @findex GDB_OSABI_WINCE | |
2653 | @item GDB_OSABI_WINCE | |
f4b3909f | 2654 | Windows CE. |
70f80edf | 2655 | |
1029b7fa MK |
2656 | @findex GDB_OSABI_GO32 |
2657 | @item GDB_OSABI_GO32 | |
f4b3909f | 2658 | DJGPP. |
1029b7fa | 2659 | |
f4b3909f EZ |
2660 | @findex GDB_OSABI_IRIX |
2661 | @item GDB_OSABI_IRIX | |
2662 | Irix. | |
2663 | ||
f4b3909f EZ |
2664 | @findex GDB_OSABI_INTERIX |
2665 | @item GDB_OSABI_INTERIX | |
2666 | Interix (Posix layer for MS-Windows systems). | |
1029b7fa | 2667 | |
f4b3909f EZ |
2668 | @findex GDB_OSABI_HPUX_ELF |
2669 | @item GDB_OSABI_HPUX_ELF | |
2670 | HP/UX using the ELF executable format. | |
70f80edf | 2671 | |
f4b3909f EZ |
2672 | @findex GDB_OSABI_HPUX_SOM |
2673 | @item GDB_OSABI_HPUX_SOM | |
2674 | HP/UX using the SOM executable format. | |
70f80edf | 2675 | |
f4b3909f EZ |
2676 | @findex GDB_OSABI_QNXNTO |
2677 | @item GDB_OSABI_QNXNTO | |
2678 | QNX Neutrino. | |
2679 | ||
2680 | @findex GDB_OSABI_CYGWIN | |
2681 | @item GDB_OSABI_CYGWIN | |
2682 | Cygwin. | |
2683 | ||
2684 | @findex GDB_OSABI_AIX | |
2685 | @item GDB_OSABI_AIX | |
2686 | AIX. | |
70f80edf JT |
2687 | |
2688 | @end table | |
2689 | ||
2690 | Here are the functions that make up the OS ABI framework: | |
2691 | ||
2692 | @deftypefun const char *gdbarch_osabi_name (enum gdb_osabi @var{osabi}) | |
2693 | Return the name of the OS ABI corresponding to @var{osabi}. | |
2694 | @end deftypefun | |
2695 | ||
c133ab7a | 2696 | @deftypefun void gdbarch_register_osabi (enum bfd_architecture @var{arch}, unsigned long @var{machine}, enum gdb_osabi @var{osabi}, void (*@var{init_osabi})(struct gdbarch_info @var{info}, struct gdbarch *@var{gdbarch})) |
70f80edf | 2697 | Register the OS ABI handler specified by @var{init_osabi} for the |
c133ab7a MK |
2698 | architecture, machine type and OS ABI specified by @var{arch}, |
2699 | @var{machine} and @var{osabi}. In most cases, a value of zero for the | |
2700 | machine type, which implies the architecture's default machine type, | |
2701 | will suffice. | |
70f80edf JT |
2702 | @end deftypefun |
2703 | ||
2704 | @deftypefun void gdbarch_register_osabi_sniffer (enum bfd_architecture @var{arch}, enum bfd_flavour @var{flavour}, enum gdb_osabi (*@var{sniffer})(bfd *@var{abfd})) | |
2705 | Register the OS ABI file sniffer specified by @var{sniffer} for the | |
2706 | BFD architecture/flavour pair specified by @var{arch} and @var{flavour}. | |
2707 | If @var{arch} is @code{bfd_arch_unknown}, the sniffer is considered to | |
2708 | be generic, and is allowed to examine @var{flavour}-flavoured files for | |
2709 | any architecture. | |
2710 | @end deftypefun | |
2711 | ||
2712 | @deftypefun enum gdb_osabi gdbarch_lookup_osabi (bfd *@var{abfd}) | |
2713 | Examine the file described by @var{abfd} to determine its OS ABI. | |
2714 | The value @code{GDB_OSABI_UNKNOWN} is returned if the OS ABI cannot | |
2715 | be determined. | |
2716 | @end deftypefun | |
2717 | ||
2718 | @deftypefun void gdbarch_init_osabi (struct gdbarch info @var{info}, struct gdbarch *@var{gdbarch}, enum gdb_osabi @var{osabi}) | |
2719 | Invoke the OS ABI handler corresponding to @var{osabi} to fine-tune the | |
2720 | @code{gdbarch} structure specified by @var{gdbarch}. If a handler | |
2721 | corresponding to @var{osabi} has not been registered for @var{gdbarch}'s | |
2722 | architecture, a warning will be issued and the debugging session will continue | |
2723 | with the defaults already established for @var{gdbarch}. | |
2724 | @end deftypefun | |
2725 | ||
f4b3909f EZ |
2726 | @deftypefun void generic_elf_osabi_sniff_abi_tag_sections (bfd *@var{abfd}, asection *@var{sect}, void *@var{obj}) |
2727 | Helper routine for ELF file sniffers. Examine the file described by | |
2728 | @var{abfd} and look at ABI tag note sections to determine the OS ABI | |
2729 | from the note. This function should be called via | |
2730 | @code{bfd_map_over_sections}. | |
2731 | @end deftypefun | |
2732 | ||
7a107747 DJ |
2733 | @section Initializing a New Architecture |
2734 | ||
2735 | Each @code{gdbarch} is associated with a single @sc{bfd} architecture, | |
2736 | via a @code{bfd_arch_@var{arch}} constant. The @code{gdbarch} is | |
2737 | registered by a call to @code{register_gdbarch_init}, usually from | |
2738 | the file's @code{_initialize_@var{filename}} routine, which will | |
2739 | be automatically called during @value{GDBN} startup. The arguments | |
2740 | are a @sc{bfd} architecture constant and an initialization function. | |
2741 | ||
2742 | The initialization function has this type: | |
2743 | ||
2744 | @smallexample | |
2745 | static struct gdbarch * | |
2746 | @var{arch}_gdbarch_init (struct gdbarch_info @var{info}, | |
2747 | struct gdbarch_list *@var{arches}) | |
2748 | @end smallexample | |
2749 | ||
2750 | The @var{info} argument contains parameters used to select the correct | |
2751 | architecture, and @var{arches} is a list of architectures which | |
2752 | have already been created with the same @code{bfd_arch_@var{arch}} | |
2753 | value. | |
2754 | ||
2755 | The initialization function should first make sure that @var{info} | |
2756 | is acceptable, and return @code{NULL} if it is not. Then, it should | |
2757 | search through @var{arches} for an exact match to @var{info}, and | |
2758 | return one if found. Lastly, if no exact match was found, it should | |
2759 | create a new architecture based on @var{info} and return it. | |
2760 | ||
2761 | Only information in @var{info} should be used to choose the new | |
2762 | architecture. Historically, @var{info} could be sparse, and | |
2763 | defaults would be collected from the first element on @var{arches}. | |
2764 | However, @value{GDBN} now fills in @var{info} more thoroughly, | |
2765 | so new @code{gdbarch} initialization functions should not take | |
2766 | defaults from @var{arches}. | |
2767 | ||
c906108c SS |
2768 | @section Registers and Memory |
2769 | ||
56caf160 EZ |
2770 | @value{GDBN}'s model of the target machine is rather simple. |
2771 | @value{GDBN} assumes the machine includes a bank of registers and a | |
2772 | block of memory. Each register may have a different size. | |
c906108c | 2773 | |
56caf160 EZ |
2774 | @value{GDBN} does not have a magical way to match up with the |
2775 | compiler's idea of which registers are which; however, it is critical | |
2776 | that they do match up accurately. The only way to make this work is | |
2777 | to get accurate information about the order that the compiler uses, | |
2778 | and to reflect that in the @code{REGISTER_NAME} and related macros. | |
c906108c | 2779 | |
25822942 | 2780 | @value{GDBN} can handle big-endian, little-endian, and bi-endian architectures. |
c906108c | 2781 | |
93e79dbd JB |
2782 | @section Pointers Are Not Always Addresses |
2783 | @cindex pointer representation | |
2784 | @cindex address representation | |
2785 | @cindex word-addressed machines | |
2786 | @cindex separate data and code address spaces | |
2787 | @cindex spaces, separate data and code address | |
2788 | @cindex address spaces, separate data and code | |
2789 | @cindex code pointers, word-addressed | |
2790 | @cindex converting between pointers and addresses | |
2791 | @cindex D10V addresses | |
2792 | ||
2793 | On almost all 32-bit architectures, the representation of a pointer is | |
2794 | indistinguishable from the representation of some fixed-length number | |
2795 | whose value is the byte address of the object pointed to. On such | |
56caf160 | 2796 | machines, the words ``pointer'' and ``address'' can be used interchangeably. |
93e79dbd JB |
2797 | However, architectures with smaller word sizes are often cramped for |
2798 | address space, so they may choose a pointer representation that breaks this | |
2799 | identity, and allows a larger code address space. | |
2800 | ||
172c2a43 | 2801 | For example, the Renesas D10V is a 16-bit VLIW processor whose |
93e79dbd JB |
2802 | instructions are 32 bits long@footnote{Some D10V instructions are |
2803 | actually pairs of 16-bit sub-instructions. However, since you can't | |
2804 | jump into the middle of such a pair, code addresses can only refer to | |
2805 | full 32 bit instructions, which is what matters in this explanation.}. | |
2806 | If the D10V used ordinary byte addresses to refer to code locations, | |
2807 | then the processor would only be able to address 64kb of instructions. | |
2808 | However, since instructions must be aligned on four-byte boundaries, the | |
56caf160 EZ |
2809 | low two bits of any valid instruction's byte address are always |
2810 | zero---byte addresses waste two bits. So instead of byte addresses, | |
2811 | the D10V uses word addresses---byte addresses shifted right two bits---to | |
93e79dbd JB |
2812 | refer to code. Thus, the D10V can use 16-bit words to address 256kb of |
2813 | code space. | |
2814 | ||
2815 | However, this means that code pointers and data pointers have different | |
2816 | forms on the D10V. The 16-bit word @code{0xC020} refers to byte address | |
2817 | @code{0xC020} when used as a data address, but refers to byte address | |
2818 | @code{0x30080} when used as a code address. | |
2819 | ||
2820 | (The D10V also uses separate code and data address spaces, which also | |
2821 | affects the correspondence between pointers and addresses, but we're | |
2822 | going to ignore that here; this example is already too long.) | |
2823 | ||
56caf160 EZ |
2824 | To cope with architectures like this---the D10V is not the only |
2825 | one!---@value{GDBN} tries to distinguish between @dfn{addresses}, which are | |
93e79dbd JB |
2826 | byte numbers, and @dfn{pointers}, which are the target's representation |
2827 | of an address of a particular type of data. In the example above, | |
2828 | @code{0xC020} is the pointer, which refers to one of the addresses | |
2829 | @code{0xC020} or @code{0x30080}, depending on the type imposed upon it. | |
2830 | @value{GDBN} provides functions for turning a pointer into an address | |
2831 | and vice versa, in the appropriate way for the current architecture. | |
2832 | ||
2833 | Unfortunately, since addresses and pointers are identical on almost all | |
2834 | processors, this distinction tends to bit-rot pretty quickly. Thus, | |
2835 | each time you port @value{GDBN} to an architecture which does | |
2836 | distinguish between pointers and addresses, you'll probably need to | |
2837 | clean up some architecture-independent code. | |
2838 | ||
2839 | Here are functions which convert between pointers and addresses: | |
2840 | ||
2841 | @deftypefun CORE_ADDR extract_typed_address (void *@var{buf}, struct type *@var{type}) | |
2842 | Treat the bytes at @var{buf} as a pointer or reference of type | |
2843 | @var{type}, and return the address it represents, in a manner | |
2844 | appropriate for the current architecture. This yields an address | |
2845 | @value{GDBN} can use to read target memory, disassemble, etc. Note that | |
2846 | @var{buf} refers to a buffer in @value{GDBN}'s memory, not the | |
2847 | inferior's. | |
2848 | ||
2849 | For example, if the current architecture is the Intel x86, this function | |
2850 | extracts a little-endian integer of the appropriate length from | |
2851 | @var{buf} and returns it. However, if the current architecture is the | |
2852 | D10V, this function will return a 16-bit integer extracted from | |
2853 | @var{buf}, multiplied by four if @var{type} is a pointer to a function. | |
2854 | ||
2855 | If @var{type} is not a pointer or reference type, then this function | |
2856 | will signal an internal error. | |
2857 | @end deftypefun | |
2858 | ||
2859 | @deftypefun CORE_ADDR store_typed_address (void *@var{buf}, struct type *@var{type}, CORE_ADDR @var{addr}) | |
2860 | Store the address @var{addr} in @var{buf}, in the proper format for a | |
2861 | pointer of type @var{type} in the current architecture. Note that | |
2862 | @var{buf} refers to a buffer in @value{GDBN}'s memory, not the | |
2863 | inferior's. | |
2864 | ||
2865 | For example, if the current architecture is the Intel x86, this function | |
2866 | stores @var{addr} unmodified as a little-endian integer of the | |
2867 | appropriate length in @var{buf}. However, if the current architecture | |
2868 | is the D10V, this function divides @var{addr} by four if @var{type} is | |
2869 | a pointer to a function, and then stores it in @var{buf}. | |
2870 | ||
2871 | If @var{type} is not a pointer or reference type, then this function | |
2872 | will signal an internal error. | |
2873 | @end deftypefun | |
2874 | ||
f23631e4 | 2875 | @deftypefun CORE_ADDR value_as_address (struct value *@var{val}) |
93e79dbd JB |
2876 | Assuming that @var{val} is a pointer, return the address it represents, |
2877 | as appropriate for the current architecture. | |
2878 | ||
2879 | This function actually works on integral values, as well as pointers. | |
2880 | For pointers, it performs architecture-specific conversions as | |
2881 | described above for @code{extract_typed_address}. | |
2882 | @end deftypefun | |
2883 | ||
2884 | @deftypefun CORE_ADDR value_from_pointer (struct type *@var{type}, CORE_ADDR @var{addr}) | |
2885 | Create and return a value representing a pointer of type @var{type} to | |
2886 | the address @var{addr}, as appropriate for the current architecture. | |
2887 | This function performs architecture-specific conversions as described | |
2888 | above for @code{store_typed_address}. | |
2889 | @end deftypefun | |
2890 | ||
93e79dbd JB |
2891 | Here are some macros which architectures can define to indicate the |
2892 | relationship between pointers and addresses. These have default | |
2893 | definitions, appropriate for architectures on which all pointers are | |
fc0c74b1 | 2894 | simple unsigned byte addresses. |
93e79dbd JB |
2895 | |
2896 | @deftypefn {Target Macro} CORE_ADDR POINTER_TO_ADDRESS (struct type *@var{type}, char *@var{buf}) | |
2897 | Assume that @var{buf} holds a pointer of type @var{type}, in the | |
2898 | appropriate format for the current architecture. Return the byte | |
2899 | address the pointer refers to. | |
2900 | ||
2901 | This function may safely assume that @var{type} is either a pointer or a | |
56caf160 | 2902 | C@t{++} reference type. |
93e79dbd JB |
2903 | @end deftypefn |
2904 | ||
2905 | @deftypefn {Target Macro} void ADDRESS_TO_POINTER (struct type *@var{type}, char *@var{buf}, CORE_ADDR @var{addr}) | |
2906 | Store in @var{buf} a pointer of type @var{type} representing the address | |
2907 | @var{addr}, in the appropriate format for the current architecture. | |
2908 | ||
2909 | This function may safely assume that @var{type} is either a pointer or a | |
56caf160 | 2910 | C@t{++} reference type. |
93e79dbd JB |
2911 | @end deftypefn |
2912 | ||
b5b0480a KB |
2913 | @section Address Classes |
2914 | @cindex address classes | |
2915 | @cindex DW_AT_byte_size | |
2916 | @cindex DW_AT_address_class | |
2917 | ||
2918 | Sometimes information about different kinds of addresses is available | |
2919 | via the debug information. For example, some programming environments | |
2920 | define addresses of several different sizes. If the debug information | |
2921 | distinguishes these kinds of address classes through either the size | |
2922 | info (e.g, @code{DW_AT_byte_size} in @w{DWARF 2}) or through an explicit | |
2923 | address class attribute (e.g, @code{DW_AT_address_class} in @w{DWARF 2}), the | |
2924 | following macros should be defined in order to disambiguate these | |
2925 | types within @value{GDBN} as well as provide the added information to | |
2926 | a @value{GDBN} user when printing type expressions. | |
2927 | ||
2928 | @deftypefn {Target Macro} int ADDRESS_CLASS_TYPE_FLAGS (int @var{byte_size}, int @var{dwarf2_addr_class}) | |
2929 | Returns the type flags needed to construct a pointer type whose size | |
2930 | is @var{byte_size} and whose address class is @var{dwarf2_addr_class}. | |
2931 | This function is normally called from within a symbol reader. See | |
2932 | @file{dwarf2read.c}. | |
2933 | @end deftypefn | |
2934 | ||
2935 | @deftypefn {Target Macro} char *ADDRESS_CLASS_TYPE_FLAGS_TO_NAME (int @var{type_flags}) | |
2936 | Given the type flags representing an address class qualifier, return | |
2937 | its name. | |
2938 | @end deftypefn | |
2939 | @deftypefn {Target Macro} int ADDRESS_CLASS_NAME_to_TYPE_FLAGS (int @var{name}, int *var{type_flags_ptr}) | |
d3e8051b | 2940 | Given an address qualifier name, set the @code{int} referenced by @var{type_flags_ptr} to the type flags |
b5b0480a KB |
2941 | for that address class qualifier. |
2942 | @end deftypefn | |
2943 | ||
2944 | Since the need for address classes is rather rare, none of | |
2945 | the address class macros defined by default. Predicate | |
2946 | macros are provided to detect when they are defined. | |
2947 | ||
2948 | Consider a hypothetical architecture in which addresses are normally | |
2949 | 32-bits wide, but 16-bit addresses are also supported. Furthermore, | |
2950 | suppose that the @w{DWARF 2} information for this architecture simply | |
2951 | uses a @code{DW_AT_byte_size} value of 2 to indicate the use of one | |
2952 | of these "short" pointers. The following functions could be defined | |
2953 | to implement the address class macros: | |
2954 | ||
2955 | @smallexample | |
2956 | somearch_address_class_type_flags (int byte_size, | |
2957 | int dwarf2_addr_class) | |
f2abfe65 | 2958 | @{ |
b5b0480a KB |
2959 | if (byte_size == 2) |
2960 | return TYPE_FLAG_ADDRESS_CLASS_1; | |
2961 | else | |
2962 | return 0; | |
f2abfe65 | 2963 | @} |
b5b0480a KB |
2964 | |
2965 | static char * | |
2966 | somearch_address_class_type_flags_to_name (int type_flags) | |
f2abfe65 | 2967 | @{ |
b5b0480a KB |
2968 | if (type_flags & TYPE_FLAG_ADDRESS_CLASS_1) |
2969 | return "short"; | |
2970 | else | |
2971 | return NULL; | |
f2abfe65 | 2972 | @} |
b5b0480a KB |
2973 | |
2974 | int | |
2975 | somearch_address_class_name_to_type_flags (char *name, | |
2976 | int *type_flags_ptr) | |
f2abfe65 | 2977 | @{ |
b5b0480a | 2978 | if (strcmp (name, "short") == 0) |
f2abfe65 | 2979 | @{ |
b5b0480a KB |
2980 | *type_flags_ptr = TYPE_FLAG_ADDRESS_CLASS_1; |
2981 | return 1; | |
f2abfe65 | 2982 | @} |
b5b0480a KB |
2983 | else |
2984 | return 0; | |
f2abfe65 | 2985 | @} |
b5b0480a KB |
2986 | @end smallexample |
2987 | ||
2988 | The qualifier @code{@@short} is used in @value{GDBN}'s type expressions | |
2989 | to indicate the presence of one of these "short" pointers. E.g, if | |
2990 | the debug information indicates that @code{short_ptr_var} is one of these | |
2991 | short pointers, @value{GDBN} might show the following behavior: | |
2992 | ||
2993 | @smallexample | |
2994 | (gdb) ptype short_ptr_var | |
2995 | type = int * @@short | |
2996 | @end smallexample | |
2997 | ||
93e79dbd | 2998 | |
13d01224 AC |
2999 | @section Raw and Virtual Register Representations |
3000 | @cindex raw register representation | |
3001 | @cindex virtual register representation | |
3002 | @cindex representations, raw and virtual registers | |
3003 | ||
3004 | @emph{Maintainer note: This section is pretty much obsolete. The | |
3005 | functionality described here has largely been replaced by | |
3006 | pseudo-registers and the mechanisms described in @ref{Target | |
3007 | Architecture Definition, , Using Different Register and Memory Data | |
3008 | Representations}. See also @uref{http://www.gnu.org/software/gdb/bugs/, | |
3009 | Bug Tracking Database} and | |
3010 | @uref{http://sources.redhat.com/gdb/current/ari/, ARI Index} for more | |
3011 | up-to-date information.} | |
af6c57ea | 3012 | |
9fb4dd36 JB |
3013 | Some architectures use one representation for a value when it lives in a |
3014 | register, but use a different representation when it lives in memory. | |
25822942 | 3015 | In @value{GDBN}'s terminology, the @dfn{raw} representation is the one used in |
9fb4dd36 | 3016 | the target registers, and the @dfn{virtual} representation is the one |
25822942 | 3017 | used in memory, and within @value{GDBN} @code{struct value} objects. |
9fb4dd36 | 3018 | |
13d01224 AC |
3019 | @emph{Maintainer note: Notice that the same mechanism is being used to |
3020 | both convert a register to a @code{struct value} and alternative | |
3021 | register forms.} | |
3022 | ||
9fb4dd36 JB |
3023 | For almost all data types on almost all architectures, the virtual and |
3024 | raw representations are identical, and no special handling is needed. | |
3025 | However, they do occasionally differ. For example: | |
3026 | ||
3027 | @itemize @bullet | |
9fb4dd36 | 3028 | @item |
56caf160 | 3029 | The x86 architecture supports an 80-bit @code{long double} type. However, when |
9fb4dd36 JB |
3030 | we store those values in memory, they occupy twelve bytes: the |
3031 | floating-point number occupies the first ten, and the final two bytes | |
3032 | are unused. This keeps the values aligned on four-byte boundaries, | |
3033 | allowing more efficient access. Thus, the x86 80-bit floating-point | |
3034 | type is the raw representation, and the twelve-byte loosely-packed | |
3035 | arrangement is the virtual representation. | |
3036 | ||
3037 | @item | |
25822942 DB |
3038 | Some 64-bit MIPS targets present 32-bit registers to @value{GDBN} as 64-bit |
3039 | registers, with garbage in their upper bits. @value{GDBN} ignores the top 32 | |
9fb4dd36 JB |
3040 | bits. Thus, the 64-bit form, with garbage in the upper 32 bits, is the |
3041 | raw representation, and the trimmed 32-bit representation is the | |
3042 | virtual representation. | |
9fb4dd36 JB |
3043 | @end itemize |
3044 | ||
3045 | In general, the raw representation is determined by the architecture, or | |
25822942 DB |
3046 | @value{GDBN}'s interface to the architecture, while the virtual representation |
3047 | can be chosen for @value{GDBN}'s convenience. @value{GDBN}'s register file, | |
56caf160 EZ |
3048 | @code{registers}, holds the register contents in raw format, and the |
3049 | @value{GDBN} remote protocol transmits register values in raw format. | |
9fb4dd36 | 3050 | |
56caf160 EZ |
3051 | Your architecture may define the following macros to request |
3052 | conversions between the raw and virtual format: | |
9fb4dd36 JB |
3053 | |
3054 | @deftypefn {Target Macro} int REGISTER_CONVERTIBLE (int @var{reg}) | |
3055 | Return non-zero if register number @var{reg}'s value needs different raw | |
3056 | and virtual formats. | |
6f6ef15a EZ |
3057 | |
3058 | You should not use @code{REGISTER_CONVERT_TO_VIRTUAL} for a register | |
3059 | unless this macro returns a non-zero value for that register. | |
9fb4dd36 JB |
3060 | @end deftypefn |
3061 | ||
12c266ea | 3062 | @deftypefn {Target Macro} int DEPRECATED_REGISTER_RAW_SIZE (int @var{reg}) |
9fb4dd36 | 3063 | The size of register number @var{reg}'s raw value. This is the number |
25822942 | 3064 | of bytes the register will occupy in @code{registers}, or in a @value{GDBN} |
9fb4dd36 JB |
3065 | remote protocol packet. |
3066 | @end deftypefn | |
3067 | ||
f30992d4 | 3068 | @deftypefn {Target Macro} int DEPRECATED_REGISTER_VIRTUAL_SIZE (int @var{reg}) |
9fb4dd36 JB |
3069 | The size of register number @var{reg}'s value, in its virtual format. |
3070 | This is the size a @code{struct value}'s buffer will have, holding that | |
3071 | register's value. | |
3072 | @end deftypefn | |
3073 | ||
2e092625 | 3074 | @deftypefn {Target Macro} struct type *DEPRECATED_REGISTER_VIRTUAL_TYPE (int @var{reg}) |
9fb4dd36 JB |
3075 | This is the type of the virtual representation of register number |
3076 | @var{reg}. Note that there is no need for a macro giving a type for the | |
25822942 | 3077 | register's raw form; once the register's value has been obtained, @value{GDBN} |
9fb4dd36 JB |
3078 | always uses the virtual form. |
3079 | @end deftypefn | |
3080 | ||
3081 | @deftypefn {Target Macro} void REGISTER_CONVERT_TO_VIRTUAL (int @var{reg}, struct type *@var{type}, char *@var{from}, char *@var{to}) | |
3082 | Convert the value of register number @var{reg} to @var{type}, which | |
2e092625 | 3083 | should always be @code{DEPRECATED_REGISTER_VIRTUAL_TYPE (@var{reg})}. The buffer |
9fb4dd36 JB |
3084 | at @var{from} holds the register's value in raw format; the macro should |
3085 | convert the value to virtual format, and place it at @var{to}. | |
3086 | ||
6f6ef15a EZ |
3087 | Note that @code{REGISTER_CONVERT_TO_VIRTUAL} and |
3088 | @code{REGISTER_CONVERT_TO_RAW} take their @var{reg} and @var{type} | |
3089 | arguments in different orders. | |
3090 | ||
3091 | You should only use @code{REGISTER_CONVERT_TO_VIRTUAL} with registers | |
3092 | for which the @code{REGISTER_CONVERTIBLE} macro returns a non-zero | |
3093 | value. | |
9fb4dd36 JB |
3094 | @end deftypefn |
3095 | ||
3096 | @deftypefn {Target Macro} void REGISTER_CONVERT_TO_RAW (struct type *@var{type}, int @var{reg}, char *@var{from}, char *@var{to}) | |
3097 | Convert the value of register number @var{reg} to @var{type}, which | |
2e092625 | 3098 | should always be @code{DEPRECATED_REGISTER_VIRTUAL_TYPE (@var{reg})}. The buffer |
9fb4dd36 JB |
3099 | at @var{from} holds the register's value in raw format; the macro should |
3100 | convert the value to virtual format, and place it at @var{to}. | |
3101 | ||
3102 | Note that REGISTER_CONVERT_TO_VIRTUAL and REGISTER_CONVERT_TO_RAW take | |
3103 | their @var{reg} and @var{type} arguments in different orders. | |
3104 | @end deftypefn | |
3105 | ||
3106 | ||
13d01224 AC |
3107 | @section Using Different Register and Memory Data Representations |
3108 | @cindex register representation | |
3109 | @cindex memory representation | |
3110 | @cindex representations, register and memory | |
3111 | @cindex register data formats, converting | |
3112 | @cindex @code{struct value}, converting register contents to | |
3113 | ||
3114 | @emph{Maintainer's note: The way GDB manipulates registers is undergoing | |
d3e8051b | 3115 | significant change. Many of the macros and functions referred to in this |
13d01224 AC |
3116 | section are likely to be subject to further revision. See |
3117 | @uref{http://sources.redhat.com/gdb/current/ari/, A.R. Index} and | |
3118 | @uref{http://www.gnu.org/software/gdb/bugs, Bug Tracking Database} for | |
3119 | further information. cagney/2002-05-06.} | |
3120 | ||
3121 | Some architectures can represent a data object in a register using a | |
3122 | form that is different to the objects more normal memory representation. | |
3123 | For example: | |
3124 | ||
3125 | @itemize @bullet | |
3126 | ||
3127 | @item | |
3128 | The Alpha architecture can represent 32 bit integer values in | |
3129 | floating-point registers. | |
3130 | ||
3131 | @item | |
3132 | The x86 architecture supports 80-bit floating-point registers. The | |
3133 | @code{long double} data type occupies 96 bits in memory but only 80 bits | |
3134 | when stored in a register. | |
3135 | ||
3136 | @end itemize | |
3137 | ||
3138 | In general, the register representation of a data type is determined by | |
3139 | the architecture, or @value{GDBN}'s interface to the architecture, while | |
3140 | the memory representation is determined by the Application Binary | |
3141 | Interface. | |
3142 | ||
3143 | For almost all data types on almost all architectures, the two | |
3144 | representations are identical, and no special handling is needed. | |
3145 | However, they do occasionally differ. Your architecture may define the | |
3146 | following macros to request conversions between the register and memory | |
3147 | representations of a data type: | |
3148 | ||
3149 | @deftypefn {Target Macro} int CONVERT_REGISTER_P (int @var{reg}) | |
3150 | Return non-zero if the representation of a data value stored in this | |
3151 | register may be different to the representation of that same data value | |
3152 | when stored in memory. | |
3153 | ||
3154 | When non-zero, the macros @code{REGISTER_TO_VALUE} and | |
3155 | @code{VALUE_TO_REGISTER} are used to perform any necessary conversion. | |
3156 | @end deftypefn | |
3157 | ||
3158 | @deftypefn {Target Macro} void REGISTER_TO_VALUE (int @var{reg}, struct type *@var{type}, char *@var{from}, char *@var{to}) | |
3159 | Convert the value of register number @var{reg} to a data object of type | |
3160 | @var{type}. The buffer at @var{from} holds the register's value in raw | |
3161 | format; the converted value should be placed in the buffer at @var{to}. | |
3162 | ||
3163 | Note that @code{REGISTER_TO_VALUE} and @code{VALUE_TO_REGISTER} take | |
3164 | their @var{reg} and @var{type} arguments in different orders. | |
3165 | ||
3166 | You should only use @code{REGISTER_TO_VALUE} with registers for which | |
3167 | the @code{CONVERT_REGISTER_P} macro returns a non-zero value. | |
3168 | @end deftypefn | |
3169 | ||
3170 | @deftypefn {Target Macro} void VALUE_TO_REGISTER (struct type *@var{type}, int @var{reg}, char *@var{from}, char *@var{to}) | |
3171 | Convert a data value of type @var{type} to register number @var{reg}' | |
3172 | raw format. | |
3173 | ||
3174 | Note that @code{REGISTER_TO_VALUE} and @code{VALUE_TO_REGISTER} take | |
3175 | their @var{reg} and @var{type} arguments in different orders. | |
3176 | ||
3177 | You should only use @code{VALUE_TO_REGISTER} with registers for which | |
3178 | the @code{CONVERT_REGISTER_P} macro returns a non-zero value. | |
3179 | @end deftypefn | |
3180 | ||
3181 | @deftypefn {Target Macro} void REGISTER_CONVERT_TO_TYPE (int @var{regnum}, struct type *@var{type}, char *@var{buf}) | |
3182 | See @file{mips-tdep.c}. It does not do what you want. | |
3183 | @end deftypefn | |
3184 | ||
3185 | ||
c906108c SS |
3186 | @section Frame Interpretation |
3187 | ||
3188 | @section Inferior Call Setup | |
3189 | ||
3190 | @section Compiler Characteristics | |
3191 | ||
3192 | @section Target Conditionals | |
3193 | ||
3194 | This section describes the macros that you can use to define the target | |
3195 | machine. | |
3196 | ||
3197 | @table @code | |
3198 | ||
c906108c | 3199 | @item ADDR_BITS_REMOVE (addr) |
56caf160 | 3200 | @findex ADDR_BITS_REMOVE |
adf40b2e JM |
3201 | If a raw machine instruction address includes any bits that are not |
3202 | really part of the address, then define this macro to expand into an | |
56caf160 | 3203 | expression that zeroes those bits in @var{addr}. This is only used for |
adf40b2e JM |
3204 | addresses of instructions, and even then not in all contexts. |
3205 | ||
3206 | For example, the two low-order bits of the PC on the Hewlett-Packard PA | |
3207 | 2.0 architecture contain the privilege level of the corresponding | |
3208 | instruction. Since instructions must always be aligned on four-byte | |
3209 | boundaries, the processor masks out these bits to generate the actual | |
3210 | address of the instruction. ADDR_BITS_REMOVE should filter out these | |
3211 | bits with an expression such as @code{((addr) & ~3)}. | |
c906108c | 3212 | |
b5b0480a KB |
3213 | @item ADDRESS_CLASS_NAME_TO_TYPE_FLAGS (@var{name}, @var{type_flags_ptr}) |
3214 | @findex ADDRESS_CLASS_NAME_TO_TYPE_FLAGS | |
3215 | If @var{name} is a valid address class qualifier name, set the @code{int} | |
3216 | referenced by @var{type_flags_ptr} to the mask representing the qualifier | |
3217 | and return 1. If @var{name} is not a valid address class qualifier name, | |
3218 | return 0. | |
3219 | ||
3220 | The value for @var{type_flags_ptr} should be one of | |
3221 | @code{TYPE_FLAG_ADDRESS_CLASS_1}, @code{TYPE_FLAG_ADDRESS_CLASS_2}, or | |
3222 | possibly some combination of these values or'd together. | |
3223 | @xref{Target Architecture Definition, , Address Classes}. | |
3224 | ||
3225 | @item ADDRESS_CLASS_NAME_TO_TYPE_FLAGS_P () | |
3226 | @findex ADDRESS_CLASS_NAME_TO_TYPE_FLAGS_P | |
3227 | Predicate which indicates whether @code{ADDRESS_CLASS_NAME_TO_TYPE_FLAGS} | |
3228 | has been defined. | |
3229 | ||
3230 | @item ADDRESS_CLASS_TYPE_FLAGS (@var{byte_size}, @var{dwarf2_addr_class}) | |
3231 | @findex ADDRESS_CLASS_TYPE_FLAGS (@var{byte_size}, @var{dwarf2_addr_class}) | |
3232 | Given a pointers byte size (as described by the debug information) and | |
3233 | the possible @code{DW_AT_address_class} value, return the type flags | |
3234 | used by @value{GDBN} to represent this address class. The value | |
3235 | returned should be one of @code{TYPE_FLAG_ADDRESS_CLASS_1}, | |
3236 | @code{TYPE_FLAG_ADDRESS_CLASS_2}, or possibly some combination of these | |
3237 | values or'd together. | |
3238 | @xref{Target Architecture Definition, , Address Classes}. | |
3239 | ||
3240 | @item ADDRESS_CLASS_TYPE_FLAGS_P () | |
3241 | @findex ADDRESS_CLASS_TYPE_FLAGS_P | |
3242 | Predicate which indicates whether @code{ADDRESS_CLASS_TYPE_FLAGS} has | |
3243 | been defined. | |
3244 | ||
3245 | @item ADDRESS_CLASS_TYPE_FLAGS_TO_NAME (@var{type_flags}) | |
3246 | @findex ADDRESS_CLASS_TYPE_FLAGS_TO_NAME | |
3247 | Return the name of the address class qualifier associated with the type | |
3248 | flags given by @var{type_flags}. | |
3249 | ||
3250 | @item ADDRESS_CLASS_TYPE_FLAGS_TO_NAME_P () | |
3251 | @findex ADDRESS_CLASS_TYPE_FLAGS_TO_NAME_P | |
3252 | Predicate which indicates whether @code{ADDRESS_CLASS_TYPE_FLAGS_TO_NAME} has | |
3253 | been defined. | |
3254 | @xref{Target Architecture Definition, , Address Classes}. | |
3255 | ||
93e79dbd | 3256 | @item ADDRESS_TO_POINTER (@var{type}, @var{buf}, @var{addr}) |
56caf160 | 3257 | @findex ADDRESS_TO_POINTER |
93e79dbd JB |
3258 | Store in @var{buf} a pointer of type @var{type} representing the address |
3259 | @var{addr}, in the appropriate format for the current architecture. | |
3260 | This macro may safely assume that @var{type} is either a pointer or a | |
56caf160 | 3261 | C@t{++} reference type. |
93e79dbd JB |
3262 | @xref{Target Architecture Definition, , Pointers Are Not Always Addresses}. |
3263 | ||
c906108c | 3264 | @item BELIEVE_PCC_PROMOTION |
56caf160 EZ |
3265 | @findex BELIEVE_PCC_PROMOTION |
3266 | Define if the compiler promotes a @code{short} or @code{char} | |
3267 | parameter to an @code{int}, but still reports the parameter as its | |
3268 | original type, rather than the promoted type. | |
c906108c | 3269 | |
c906108c | 3270 | @item BITS_BIG_ENDIAN |
56caf160 EZ |
3271 | @findex BITS_BIG_ENDIAN |
3272 | Define this if the numbering of bits in the targets does @strong{not} match the | |
c906108c | 3273 | endianness of the target byte order. A value of 1 means that the bits |
56caf160 | 3274 | are numbered in a big-endian bit order, 0 means little-endian. |
c906108c SS |
3275 | |
3276 | @item BREAKPOINT | |
56caf160 | 3277 | @findex BREAKPOINT |
c906108c SS |
3278 | This is the character array initializer for the bit pattern to put into |
3279 | memory where a breakpoint is set. Although it's common to use a trap | |
3280 | instruction for a breakpoint, it's not required; for instance, the bit | |
3281 | pattern could be an invalid instruction. The breakpoint must be no | |
3282 | longer than the shortest instruction of the architecture. | |
3283 | ||
56caf160 EZ |
3284 | @code{BREAKPOINT} has been deprecated in favor of |
3285 | @code{BREAKPOINT_FROM_PC}. | |
7a292a7a | 3286 | |
c906108c | 3287 | @item BIG_BREAKPOINT |
56caf160 EZ |
3288 | @itemx LITTLE_BREAKPOINT |
3289 | @findex LITTLE_BREAKPOINT | |
3290 | @findex BIG_BREAKPOINT | |
c906108c SS |
3291 | Similar to BREAKPOINT, but used for bi-endian targets. |
3292 | ||
56caf160 EZ |
3293 | @code{BIG_BREAKPOINT} and @code{LITTLE_BREAKPOINT} have been deprecated in |
3294 | favor of @code{BREAKPOINT_FROM_PC}. | |
7a292a7a | 3295 | |
56caf160 EZ |
3296 | @item BREAKPOINT_FROM_PC (@var{pcptr}, @var{lenptr}) |
3297 | @findex BREAKPOINT_FROM_PC | |
2dd0da42 AC |
3298 | @anchor{BREAKPOINT_FROM_PC} Use the program counter to determine the |
3299 | contents and size of a breakpoint instruction. It returns a pointer to | |
3300 | a string of bytes that encode a breakpoint instruction, stores the | |
3301 | length of the string to @code{*@var{lenptr}}, and adjusts the program | |
3302 | counter (if necessary) to point to the actual memory location where the | |
3303 | breakpoint should be inserted. | |
c906108c SS |
3304 | |
3305 | Although it is common to use a trap instruction for a breakpoint, it's | |
3306 | not required; for instance, the bit pattern could be an invalid | |
3307 | instruction. The breakpoint must be no longer than the shortest | |
3308 | instruction of the architecture. | |
3309 | ||
7a292a7a SS |
3310 | Replaces all the other @var{BREAKPOINT} macros. |
3311 | ||
8181d85f DJ |
3312 | @item MEMORY_INSERT_BREAKPOINT (@var{bp_tgt}) |
3313 | @itemx MEMORY_REMOVE_BREAKPOINT (@var{bp_tgt}) | |
56caf160 EZ |
3314 | @findex MEMORY_REMOVE_BREAKPOINT |
3315 | @findex MEMORY_INSERT_BREAKPOINT | |
917317f4 JM |
3316 | Insert or remove memory based breakpoints. Reasonable defaults |
3317 | (@code{default_memory_insert_breakpoint} and | |
3318 | @code{default_memory_remove_breakpoint} respectively) have been | |
3319 | provided so that it is not necessary to define these for most | |
3320 | architectures. Architectures which may want to define | |
56caf160 | 3321 | @code{MEMORY_INSERT_BREAKPOINT} and @code{MEMORY_REMOVE_BREAKPOINT} will |
917317f4 JM |
3322 | likely have instructions that are oddly sized or are not stored in a |
3323 | conventional manner. | |
3324 | ||
3325 | It may also be desirable (from an efficiency standpoint) to define | |
3326 | custom breakpoint insertion and removal routines if | |
56caf160 | 3327 | @code{BREAKPOINT_FROM_PC} needs to read the target's memory for some |
917317f4 JM |
3328 | reason. |
3329 | ||
1485d690 KB |
3330 | @item ADJUST_BREAKPOINT_ADDRESS (@var{address}) |
3331 | @findex ADJUST_BREAKPOINT_ADDRESS | |
3332 | @cindex breakpoint address adjusted | |
3333 | Given an address at which a breakpoint is desired, return a breakpoint | |
3334 | address adjusted to account for architectural constraints on | |
3335 | breakpoint placement. This method is not needed by most targets. | |
3336 | ||
3337 | The FR-V target (see @file{frv-tdep.c}) requires this method. | |
3338 | The FR-V is a VLIW architecture in which a number of RISC-like | |
3339 | instructions are grouped (packed) together into an aggregate | |
3340 | instruction or instruction bundle. When the processor executes | |
3341 | one of these bundles, the component instructions are executed | |
3342 | in parallel. | |
3343 | ||
3344 | In the course of optimization, the compiler may group instructions | |
3345 | from distinct source statements into the same bundle. The line number | |
3346 | information associated with one of the latter statements will likely | |
3347 | refer to some instruction other than the first one in the bundle. So, | |
3348 | if the user attempts to place a breakpoint on one of these latter | |
3349 | statements, @value{GDBN} must be careful to @emph{not} place the break | |
3350 | instruction on any instruction other than the first one in the bundle. | |
3351 | (Remember though that the instructions within a bundle execute | |
3352 | in parallel, so the @emph{first} instruction is the instruction | |
3353 | at the lowest address and has nothing to do with execution order.) | |
3354 | ||
3355 | The FR-V's @code{ADJUST_BREAKPOINT_ADDRESS} method will adjust a | |
3356 | breakpoint's address by scanning backwards for the beginning of | |
3357 | the bundle, returning the address of the bundle. | |
3358 | ||
3359 | Since the adjustment of a breakpoint may significantly alter a user's | |
3360 | expectation, @value{GDBN} prints a warning when an adjusted breakpoint | |
3361 | is initially set and each time that that breakpoint is hit. | |
3362 | ||
c906108c | 3363 | @item CALL_DUMMY_LOCATION |
56caf160 EZ |
3364 | @findex CALL_DUMMY_LOCATION |
3365 | See the file @file{inferior.h}. | |
7a292a7a | 3366 | |
7043d8dc AC |
3367 | This method has been replaced by @code{push_dummy_code} |
3368 | (@pxref{push_dummy_code}). | |
3369 | ||
56caf160 EZ |
3370 | @item CANNOT_FETCH_REGISTER (@var{regno}) |
3371 | @findex CANNOT_FETCH_REGISTER | |
c906108c SS |
3372 | A C expression that should be nonzero if @var{regno} cannot be fetched |
3373 | from an inferior process. This is only relevant if | |
3374 | @code{FETCH_INFERIOR_REGISTERS} is not defined. | |
3375 | ||
56caf160 EZ |
3376 | @item CANNOT_STORE_REGISTER (@var{regno}) |
3377 | @findex CANNOT_STORE_REGISTER | |
c906108c SS |
3378 | A C expression that should be nonzero if @var{regno} should not be |
3379 | written to the target. This is often the case for program counters, | |
56caf160 EZ |
3380 | status words, and other special registers. If this is not defined, |
3381 | @value{GDBN} will assume that all registers may be written. | |
c906108c | 3382 | |
13d01224 AC |
3383 | @item int CONVERT_REGISTER_P(@var{regnum}) |
3384 | @findex CONVERT_REGISTER_P | |
3385 | Return non-zero if register @var{regnum} can represent data values in a | |
3386 | non-standard form. | |
3387 | @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. | |
3388 | ||
c906108c | 3389 | @item DECR_PC_AFTER_BREAK |
56caf160 | 3390 | @findex DECR_PC_AFTER_BREAK |
c906108c SS |
3391 | Define this to be the amount by which to decrement the PC after the |
3392 | program encounters a breakpoint. This is often the number of bytes in | |
56caf160 | 3393 | @code{BREAKPOINT}, though not always. For most targets this value will be 0. |
c906108c | 3394 | |
56caf160 EZ |
3395 | @item DISABLE_UNSETTABLE_BREAK (@var{addr}) |
3396 | @findex DISABLE_UNSETTABLE_BREAK | |
c906108c SS |
3397 | If defined, this should evaluate to 1 if @var{addr} is in a shared |
3398 | library in which breakpoints cannot be set and so should be disabled. | |
3399 | ||
5e74b15c | 3400 | @item PRINT_FLOAT_INFO() |
0ab7a791 | 3401 | @findex PRINT_FLOAT_INFO |
5e74b15c RE |
3402 | If defined, then the @samp{info float} command will print information about |
3403 | the processor's floating point unit. | |
3404 | ||
0ab7a791 AC |
3405 | @item print_registers_info (@var{gdbarch}, @var{frame}, @var{regnum}, @var{all}) |
3406 | @findex print_registers_info | |
3407 | If defined, pretty print the value of the register @var{regnum} for the | |
3408 | specified @var{frame}. If the value of @var{regnum} is -1, pretty print | |
3409 | either all registers (@var{all} is non zero) or a select subset of | |
3410 | registers (@var{all} is zero). | |
3411 | ||
3412 | The default method prints one register per line, and if @var{all} is | |
3413 | zero omits floating-point registers. | |
3414 | ||
e76f1f2e AC |
3415 | @item PRINT_VECTOR_INFO() |
3416 | @findex PRINT_VECTOR_INFO | |
3417 | If defined, then the @samp{info vector} command will call this function | |
3418 | to print information about the processor's vector unit. | |
3419 | ||
3420 | By default, the @samp{info vector} command will print all vector | |
3421 | registers (the register's type having the vector attribute). | |
3422 | ||
0dcedd82 | 3423 | @item DWARF_REG_TO_REGNUM |
56caf160 | 3424 | @findex DWARF_REG_TO_REGNUM |
0dcedd82 AC |
3425 | Convert DWARF register number into @value{GDBN} regnum. If not defined, |
3426 | no conversion will be performed. | |
3427 | ||
3428 | @item DWARF2_REG_TO_REGNUM | |
56caf160 | 3429 | @findex DWARF2_REG_TO_REGNUM |
0dcedd82 AC |
3430 | Convert DWARF2 register number into @value{GDBN} regnum. If not |
3431 | defined, no conversion will be performed. | |
3432 | ||
3433 | @item ECOFF_REG_TO_REGNUM | |
56caf160 | 3434 | @findex ECOFF_REG_TO_REGNUM |
0dcedd82 AC |
3435 | Convert ECOFF register number into @value{GDBN} regnum. If not defined, |
3436 | no conversion will be performed. | |
3437 | ||
c906108c | 3438 | @item END_OF_TEXT_DEFAULT |
56caf160 EZ |
3439 | @findex END_OF_TEXT_DEFAULT |
3440 | This is an expression that should designate the end of the text section. | |
3441 | @c (? FIXME ?) | |
c906108c | 3442 | |
56caf160 EZ |
3443 | @item EXTRACT_RETURN_VALUE(@var{type}, @var{regbuf}, @var{valbuf}) |
3444 | @findex EXTRACT_RETURN_VALUE | |
c906108c SS |
3445 | Define this to extract a function's return value of type @var{type} from |
3446 | the raw register state @var{regbuf} and copy that, in virtual format, | |
3447 | into @var{valbuf}. | |
3448 | ||
92ad9cd9 AC |
3449 | This method has been deprecated in favour of @code{gdbarch_return_value} |
3450 | (@pxref{gdbarch_return_value}). | |
3451 | ||
74055713 AC |
3452 | @item DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS(@var{regbuf}) |
3453 | @findex DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS | |
3454 | @anchor{DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS} | |
83aa8bc6 AC |
3455 | When defined, extract from the array @var{regbuf} (containing the raw |
3456 | register state) the @code{CORE_ADDR} at which a function should return | |
3457 | its structure value. | |
ac9a91a7 | 3458 | |
92ad9cd9 | 3459 | @xref{gdbarch_return_value}. |
83aa8bc6 | 3460 | |
74055713 AC |
3461 | @item DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS_P() |
3462 | @findex DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS_P | |
3463 | Predicate for @code{DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS}. | |
c906108c | 3464 | |
0ba6dca9 AC |
3465 | @item DEPRECATED_FP_REGNUM |
3466 | @findex DEPRECATED_FP_REGNUM | |
cce74817 JM |
3467 | If the virtual frame pointer is kept in a register, then define this |
3468 | macro to be the number (greater than or equal to zero) of that register. | |
3469 | ||
0ba6dca9 AC |
3470 | This should only need to be defined if @code{DEPRECATED_TARGET_READ_FP} |
3471 | is not defined. | |
c906108c | 3472 | |
19772a2c AC |
3473 | @item DEPRECATED_FRAMELESS_FUNCTION_INVOCATION(@var{fi}) |
3474 | @findex DEPRECATED_FRAMELESS_FUNCTION_INVOCATION | |
392a587b JM |
3475 | Define this to an expression that returns 1 if the function invocation |
3476 | represented by @var{fi} does not have a stack frame associated with it. | |
3477 | Otherwise return 0. | |
c906108c | 3478 | |
790eb8f5 AC |
3479 | @item frame_align (@var{address}) |
3480 | @anchor{frame_align} | |
3481 | @findex frame_align | |
3482 | Define this to adjust @var{address} so that it meets the alignment | |
3483 | requirements for the start of a new stack frame. A stack frame's | |
3484 | alignment requirements are typically stronger than a target processors | |
f27dd7fd | 3485 | stack alignment requirements (@pxref{DEPRECATED_STACK_ALIGN}). |
790eb8f5 AC |
3486 | |
3487 | This function is used to ensure that, when creating a dummy frame, both | |
3488 | the initial stack pointer and (if needed) the address of the return | |
3489 | value are correctly aligned. | |
3490 | ||
f27dd7fd AC |
3491 | Unlike @code{DEPRECATED_STACK_ALIGN}, this function always adjusts the |
3492 | address in the direction of stack growth. | |
790eb8f5 AC |
3493 | |
3494 | By default, no frame based stack alignment is performed. | |
3495 | ||
8b148df9 AC |
3496 | @item int frame_red_zone_size |
3497 | ||
3498 | The number of bytes, beyond the innermost-stack-address, reserved by the | |
3499 | @sc{abi}. A function is permitted to use this scratch area (instead of | |
3500 | allocating extra stack space). | |
3501 | ||
3502 | When performing an inferior function call, to ensure that it does not | |
3503 | modify this area, @value{GDBN} adjusts the innermost-stack-address by | |
3504 | @var{frame_red_zone_size} bytes before pushing parameters onto the | |
3505 | stack. | |
3506 | ||
3507 | By default, zero bytes are allocated. The value must be aligned | |
3508 | (@pxref{frame_align}). | |
3509 | ||
3510 | The @sc{amd64} (nee x86-64) @sc{abi} documentation refers to the | |
3511 | @emph{red zone} when describing this scratch area. | |
3512 | @cindex red zone | |
3513 | ||
618ce49f AC |
3514 | @item DEPRECATED_FRAME_CHAIN(@var{frame}) |
3515 | @findex DEPRECATED_FRAME_CHAIN | |
c906108c SS |
3516 | Given @var{frame}, return a pointer to the calling frame. |
3517 | ||
618ce49f AC |
3518 | @item DEPRECATED_FRAME_CHAIN_VALID(@var{chain}, @var{thisframe}) |
3519 | @findex DEPRECATED_FRAME_CHAIN_VALID | |
95f90d25 DJ |
3520 | Define this to be an expression that returns zero if the given frame is an |
3521 | outermost frame, with no caller, and nonzero otherwise. Most normal | |
3522 | situations can be handled without defining this macro, including @code{NULL} | |
3523 | chain pointers, dummy frames, and frames whose PC values are inside the | |
3524 | startup file (e.g.@: @file{crt0.o}), inside @code{main}, or inside | |
3525 | @code{_start}. | |
c906108c | 3526 | |
f30ee0bc AC |
3527 | @item DEPRECATED_FRAME_INIT_SAVED_REGS(@var{frame}) |
3528 | @findex DEPRECATED_FRAME_INIT_SAVED_REGS | |
c906108c SS |
3529 | See @file{frame.h}. Determines the address of all registers in the |
3530 | current stack frame storing each in @code{frame->saved_regs}. Space for | |
3531 | @code{frame->saved_regs} shall be allocated by | |
f30ee0bc AC |
3532 | @code{DEPRECATED_FRAME_INIT_SAVED_REGS} using |
3533 | @code{frame_saved_regs_zalloc}. | |
c906108c | 3534 | |
fb8f8949 | 3535 | @code{FRAME_FIND_SAVED_REGS} is deprecated. |
c906108c | 3536 | |
56caf160 EZ |
3537 | @item FRAME_NUM_ARGS (@var{fi}) |
3538 | @findex FRAME_NUM_ARGS | |
392a587b JM |
3539 | For the frame described by @var{fi} return the number of arguments that |
3540 | are being passed. If the number of arguments is not known, return | |
3541 | @code{-1}. | |
c906108c | 3542 | |
8bedc050 AC |
3543 | @item DEPRECATED_FRAME_SAVED_PC(@var{frame}) |
3544 | @findex DEPRECATED_FRAME_SAVED_PC | |
3545 | @anchor{DEPRECATED_FRAME_SAVED_PC} Given @var{frame}, return the pc | |
3546 | saved there. This is the return address. | |
12cc2063 AC |
3547 | |
3548 | This method is deprecated. @xref{unwind_pc}. | |
3549 | ||
3550 | @item CORE_ADDR unwind_pc (struct frame_info *@var{this_frame}) | |
3551 | @findex unwind_pc | |
3552 | @anchor{unwind_pc} Return the instruction address, in @var{this_frame}'s | |
3553 | caller, at which execution will resume after @var{this_frame} returns. | |
d3e8051b | 3554 | This is commonly referred to as the return address. |
12cc2063 AC |
3555 | |
3556 | The implementation, which must be frame agnostic (work with any frame), | |
3557 | is typically no more than: | |
3558 | ||
3559 | @smallexample | |
3560 | ULONGEST pc; | |
3561 | frame_unwind_unsigned_register (this_frame, D10V_PC_REGNUM, &pc); | |
3562 | return d10v_make_iaddr (pc); | |
3563 | @end smallexample | |
3564 | ||
3565 | @noindent | |
8bedc050 | 3566 | @xref{DEPRECATED_FRAME_SAVED_PC}, which this method replaces. |
c906108c | 3567 | |
a9e5fdc2 AC |
3568 | @item CORE_ADDR unwind_sp (struct frame_info *@var{this_frame}) |
3569 | @findex unwind_sp | |
3570 | @anchor{unwind_sp} Return the frame's inner most stack address. This is | |
d3e8051b | 3571 | commonly referred to as the frame's @dfn{stack pointer}. |
a9e5fdc2 AC |
3572 | |
3573 | The implementation, which must be frame agnostic (work with any frame), | |
3574 | is typically no more than: | |
3575 | ||
3576 | @smallexample | |
3577 | ULONGEST sp; | |
3578 | frame_unwind_unsigned_register (this_frame, D10V_SP_REGNUM, &sp); | |
3579 | return d10v_make_daddr (sp); | |
3580 | @end smallexample | |
3581 | ||
3582 | @noindent | |
3583 | @xref{TARGET_READ_SP}, which this method replaces. | |
3584 | ||
c906108c | 3585 | @item FUNCTION_EPILOGUE_SIZE |
56caf160 | 3586 | @findex FUNCTION_EPILOGUE_SIZE |
c906108c SS |
3587 | For some COFF targets, the @code{x_sym.x_misc.x_fsize} field of the |
3588 | function end symbol is 0. For such targets, you must define | |
3589 | @code{FUNCTION_EPILOGUE_SIZE} to expand into the standard size of a | |
3590 | function's epilogue. | |
3591 | ||
782263ab AC |
3592 | @item DEPRECATED_FUNCTION_START_OFFSET |
3593 | @findex DEPRECATED_FUNCTION_START_OFFSET | |
f7cb2b90 JB |
3594 | An integer, giving the offset in bytes from a function's address (as |
3595 | used in the values of symbols, function pointers, etc.), and the | |
3596 | function's first genuine instruction. | |
3597 | ||
3598 | This is zero on almost all machines: the function's address is usually | |
782263ab AC |
3599 | the address of its first instruction. However, on the VAX, for |
3600 | example, each function starts with two bytes containing a bitmask | |
3601 | indicating which registers to save upon entry to the function. The | |
3602 | VAX @code{call} instructions check this value, and save the | |
3603 | appropriate registers automatically. Thus, since the offset from the | |
3604 | function's address to its first instruction is two bytes, | |
3605 | @code{DEPRECATED_FUNCTION_START_OFFSET} would be 2 on the VAX. | |
f7cb2b90 | 3606 | |
c906108c | 3607 | @item GCC_COMPILED_FLAG_SYMBOL |
56caf160 EZ |
3608 | @itemx GCC2_COMPILED_FLAG_SYMBOL |
3609 | @findex GCC2_COMPILED_FLAG_SYMBOL | |
3610 | @findex GCC_COMPILED_FLAG_SYMBOL | |
3611 | If defined, these are the names of the symbols that @value{GDBN} will | |
3612 | look for to detect that GCC compiled the file. The default symbols | |
3613 | are @code{gcc_compiled.} and @code{gcc2_compiled.}, | |
3614 | respectively. (Currently only defined for the Delta 68.) | |
c906108c | 3615 | |
25822942 | 3616 | @item @value{GDBN}_MULTI_ARCH |
56caf160 | 3617 | @findex @value{GDBN}_MULTI_ARCH |
937f164b | 3618 | If defined and non-zero, enables support for multiple architectures |
25822942 | 3619 | within @value{GDBN}. |
0f71a2f6 | 3620 | |
56caf160 | 3621 | This support can be enabled at two levels. At level one, only |
0f71a2f6 | 3622 | definitions for previously undefined macros are provided; at level two, |
937f164b | 3623 | a multi-arch definition of all architecture dependent macros will be |
0f71a2f6 JM |
3624 | defined. |
3625 | ||
25822942 | 3626 | @item @value{GDBN}_TARGET_IS_HPPA |
56caf160 EZ |
3627 | @findex @value{GDBN}_TARGET_IS_HPPA |
3628 | This determines whether horrible kludge code in @file{dbxread.c} and | |
3629 | @file{partial-stab.h} is used to mangle multiple-symbol-table files from | |
3630 | HPPA's. This should all be ripped out, and a scheme like @file{elfread.c} | |
3631 | used instead. | |
c906108c | 3632 | |
c906108c | 3633 | @item GET_LONGJMP_TARGET |
56caf160 | 3634 | @findex GET_LONGJMP_TARGET |
c906108c SS |
3635 | For most machines, this is a target-dependent parameter. On the |
3636 | DECstation and the Iris, this is a native-dependent parameter, since | |
937f164b | 3637 | the header file @file{setjmp.h} is needed to define it. |
c906108c | 3638 | |
56caf160 EZ |
3639 | This macro determines the target PC address that @code{longjmp} will jump to, |
3640 | assuming that we have just stopped at a @code{longjmp} breakpoint. It takes a | |
3641 | @code{CORE_ADDR *} as argument, and stores the target PC value through this | |
c906108c SS |
3642 | pointer. It examines the current state of the machine as needed. |
3643 | ||
ac2adee5 AC |
3644 | @item DEPRECATED_GET_SAVED_REGISTER |
3645 | @findex DEPRECATED_GET_SAVED_REGISTER | |
c906108c | 3646 | Define this if you need to supply your own definition for the function |
ac2adee5 | 3647 | @code{DEPRECATED_GET_SAVED_REGISTER}. |
c906108c | 3648 | |
268e2188 AC |
3649 | @item DEPRECATED_IBM6000_TARGET |
3650 | @findex DEPRECATED_IBM6000_TARGET | |
3651 | Shows that we are configured for an IBM RS/6000 system. This | |
c906108c | 3652 | conditional should be eliminated (FIXME) and replaced by |
56caf160 | 3653 | feature-specific macros. It was introduced in a haste and we are |
c906108c SS |
3654 | repenting at leisure. |
3655 | ||
9742079a EZ |
3656 | @item I386_USE_GENERIC_WATCHPOINTS |
3657 | An x86-based target can define this to use the generic x86 watchpoint | |
3658 | support; see @ref{Algorithms, I386_USE_GENERIC_WATCHPOINTS}. | |
3659 | ||
2df3850c | 3660 | @item SYMBOLS_CAN_START_WITH_DOLLAR |
56caf160 | 3661 | @findex SYMBOLS_CAN_START_WITH_DOLLAR |
2df3850c | 3662 | Some systems have routines whose names start with @samp{$}. Giving this |
25822942 | 3663 | macro a non-zero value tells @value{GDBN}'s expression parser to check for such |
2df3850c JM |
3664 | routines when parsing tokens that begin with @samp{$}. |
3665 | ||
3666 | On HP-UX, certain system routines (millicode) have names beginning with | |
3667 | @samp{$} or @samp{$$}. For example, @code{$$dyncall} is a millicode | |
3668 | routine that handles inter-space procedure calls on PA-RISC. | |
3669 | ||
e9582e71 AC |
3670 | @item DEPRECATED_INIT_EXTRA_FRAME_INFO (@var{fromleaf}, @var{frame}) |
3671 | @findex DEPRECATED_INIT_EXTRA_FRAME_INFO | |
c906108c SS |
3672 | If additional information about the frame is required this should be |
3673 | stored in @code{frame->extra_info}. Space for @code{frame->extra_info} | |
372613e3 | 3674 | is allocated using @code{frame_extra_info_zalloc}. |
c906108c | 3675 | |
a5afb99f AC |
3676 | @item DEPRECATED_INIT_FRAME_PC (@var{fromleaf}, @var{prev}) |
3677 | @findex DEPRECATED_INIT_FRAME_PC | |
c906108c SS |
3678 | This is a C statement that sets the pc of the frame pointed to by |
3679 | @var{prev}. [By default...] | |
3680 | ||
56caf160 EZ |
3681 | @item INNER_THAN (@var{lhs}, @var{rhs}) |
3682 | @findex INNER_THAN | |
c906108c SS |
3683 | Returns non-zero if stack address @var{lhs} is inner than (nearer to the |
3684 | stack top) stack address @var{rhs}. Define this as @code{lhs < rhs} if | |
3685 | the target's stack grows downward in memory, or @code{lhs > rsh} if the | |
3686 | stack grows upward. | |
3687 | ||
9e5abb06 CV |
3688 | @item gdbarch_in_function_epilogue_p (@var{gdbarch}, @var{pc}) |
3689 | @findex gdbarch_in_function_epilogue_p | |
3690 | Returns non-zero if the given @var{pc} is in the epilogue of a function. | |
3691 | The epilogue of a function is defined as the part of a function where | |
3692 | the stack frame of the function already has been destroyed up to the | |
3693 | final `return from function call' instruction. | |
3694 | ||
aa2a3f87 AC |
3695 | @item DEPRECATED_SIGTRAMP_START (@var{pc}) |
3696 | @findex DEPRECATED_SIGTRAMP_START | |
3697 | @itemx DEPRECATED_SIGTRAMP_END (@var{pc}) | |
3698 | @findex DEPRECATED_SIGTRAMP_END | |
56caf160 | 3699 | Define these to be the start and end address of the @code{sigtramp} for the |
c906108c SS |
3700 | given @var{pc}. On machines where the address is just a compile time |
3701 | constant, the macro expansion will typically just ignore the supplied | |
3702 | @var{pc}. | |
3703 | ||
56caf160 EZ |
3704 | @item IN_SOLIB_CALL_TRAMPOLINE (@var{pc}, @var{name}) |
3705 | @findex IN_SOLIB_CALL_TRAMPOLINE | |
c906108c SS |
3706 | Define this to evaluate to nonzero if the program is stopped in the |
3707 | trampoline that connects to a shared library. | |
3708 | ||
56caf160 EZ |
3709 | @item IN_SOLIB_RETURN_TRAMPOLINE (@var{pc}, @var{name}) |
3710 | @findex IN_SOLIB_RETURN_TRAMPOLINE | |
c906108c SS |
3711 | Define this to evaluate to nonzero if the program is stopped in the |
3712 | trampoline that returns from a shared library. | |
3713 | ||
56caf160 EZ |
3714 | @item IN_SOLIB_DYNSYM_RESOLVE_CODE (@var{pc}) |
3715 | @findex IN_SOLIB_DYNSYM_RESOLVE_CODE | |
d4f3574e SS |
3716 | Define this to evaluate to nonzero if the program is stopped in the |
3717 | dynamic linker. | |
3718 | ||
56caf160 EZ |
3719 | @item SKIP_SOLIB_RESOLVER (@var{pc}) |
3720 | @findex SKIP_SOLIB_RESOLVER | |
d4f3574e SS |
3721 | Define this to evaluate to the (nonzero) address at which execution |
3722 | should continue to get past the dynamic linker's symbol resolution | |
3723 | function. A zero value indicates that it is not important or necessary | |
3724 | to set a breakpoint to get through the dynamic linker and that single | |
3725 | stepping will suffice. | |
3726 | ||
fc0c74b1 AC |
3727 | @item INTEGER_TO_ADDRESS (@var{type}, @var{buf}) |
3728 | @findex INTEGER_TO_ADDRESS | |
3729 | @cindex converting integers to addresses | |
3730 | Define this when the architecture needs to handle non-pointer to address | |
3731 | conversions specially. Converts that value to an address according to | |
3732 | the current architectures conventions. | |
3733 | ||
3734 | @emph{Pragmatics: When the user copies a well defined expression from | |
3735 | their source code and passes it, as a parameter, to @value{GDBN}'s | |
3736 | @code{print} command, they should get the same value as would have been | |
3737 | computed by the target program. Any deviation from this rule can cause | |
3738 | major confusion and annoyance, and needs to be justified carefully. In | |
3739 | other words, @value{GDBN} doesn't really have the freedom to do these | |
3740 | conversions in clever and useful ways. It has, however, been pointed | |
3741 | out that users aren't complaining about how @value{GDBN} casts integers | |
3742 | to pointers; they are complaining that they can't take an address from a | |
3743 | disassembly listing and give it to @code{x/i}. Adding an architecture | |
3744 | method like @code{INTEGER_TO_ADDRESS} certainly makes it possible for | |
3745 | @value{GDBN} to ``get it right'' in all circumstances.} | |
3746 | ||
3747 | @xref{Target Architecture Definition, , Pointers Are Not Always | |
3748 | Addresses}. | |
3749 | ||
c906108c | 3750 | @item NO_HIF_SUPPORT |
56caf160 | 3751 | @findex NO_HIF_SUPPORT |
c906108c SS |
3752 | (Specific to the a29k.) |
3753 | ||
93e79dbd | 3754 | @item POINTER_TO_ADDRESS (@var{type}, @var{buf}) |
56caf160 | 3755 | @findex POINTER_TO_ADDRESS |
93e79dbd JB |
3756 | Assume that @var{buf} holds a pointer of type @var{type}, in the |
3757 | appropriate format for the current architecture. Return the byte | |
3758 | address the pointer refers to. | |
3759 | @xref{Target Architecture Definition, , Pointers Are Not Always Addresses}. | |
3760 | ||
9fb4dd36 | 3761 | @item REGISTER_CONVERTIBLE (@var{reg}) |
56caf160 | 3762 | @findex REGISTER_CONVERTIBLE |
9fb4dd36 | 3763 | Return non-zero if @var{reg} uses different raw and virtual formats. |
13d01224 AC |
3764 | @xref{Target Architecture Definition, , Raw and Virtual Register Representations}. |
3765 | ||
3766 | @item REGISTER_TO_VALUE(@var{regnum}, @var{type}, @var{from}, @var{to}) | |
3767 | @findex REGISTER_TO_VALUE | |
3768 | Convert the raw contents of register @var{regnum} into a value of type | |
3769 | @var{type}. | |
4281a42e | 3770 | @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. |
9fb4dd36 | 3771 | |
12c266ea AC |
3772 | @item DEPRECATED_REGISTER_RAW_SIZE (@var{reg}) |
3773 | @findex DEPRECATED_REGISTER_RAW_SIZE | |
b2e75d78 AC |
3774 | Return the raw size of @var{reg}; defaults to the size of the register's |
3775 | virtual type. | |
13d01224 | 3776 | @xref{Target Architecture Definition, , Raw and Virtual Register Representations}. |
9fb4dd36 | 3777 | |
617073a9 AC |
3778 | @item register_reggroup_p (@var{gdbarch}, @var{regnum}, @var{reggroup}) |
3779 | @findex register_reggroup_p | |
3780 | @cindex register groups | |
3781 | Return non-zero if register @var{regnum} is a member of the register | |
3782 | group @var{reggroup}. | |
3783 | ||
3784 | By default, registers are grouped as follows: | |
3785 | ||
3786 | @table @code | |
3787 | @item float_reggroup | |
3788 | Any register with a valid name and a floating-point type. | |
3789 | @item vector_reggroup | |
3790 | Any register with a valid name and a vector type. | |
3791 | @item general_reggroup | |
3792 | Any register with a valid name and a type other than vector or | |
3793 | floating-point. @samp{float_reggroup}. | |
3794 | @item save_reggroup | |
3795 | @itemx restore_reggroup | |
3796 | @itemx all_reggroup | |
3797 | Any register with a valid name. | |
3798 | @end table | |
3799 | ||
f30992d4 AC |
3800 | @item DEPRECATED_REGISTER_VIRTUAL_SIZE (@var{reg}) |
3801 | @findex DEPRECATED_REGISTER_VIRTUAL_SIZE | |
b2e75d78 AC |
3802 | Return the virtual size of @var{reg}; defaults to the size of the |
3803 | register's virtual type. | |
13d01224 AC |
3804 | Return the virtual size of @var{reg}. |
3805 | @xref{Target Architecture Definition, , Raw and Virtual Register Representations}. | |
9fb4dd36 | 3806 | |
2e092625 | 3807 | @item DEPRECATED_REGISTER_VIRTUAL_TYPE (@var{reg}) |
56caf160 | 3808 | @findex REGISTER_VIRTUAL_TYPE |
9fb4dd36 | 3809 | Return the virtual type of @var{reg}. |
13d01224 | 3810 | @xref{Target Architecture Definition, , Raw and Virtual Register Representations}. |
9fb4dd36 | 3811 | |
77e7e267 AC |
3812 | @item struct type *register_type (@var{gdbarch}, @var{reg}) |
3813 | @findex register_type | |
3814 | If defined, return the type of register @var{reg}. This function | |
d3e8051b | 3815 | supersedes @code{DEPRECATED_REGISTER_VIRTUAL_TYPE}. @xref{Target Architecture |
77e7e267 AC |
3816 | Definition, , Raw and Virtual Register Representations}. |
3817 | ||
9fb4dd36 | 3818 | @item REGISTER_CONVERT_TO_VIRTUAL(@var{reg}, @var{type}, @var{from}, @var{to}) |
56caf160 | 3819 | @findex REGISTER_CONVERT_TO_VIRTUAL |
9fb4dd36 | 3820 | Convert the value of register @var{reg} from its raw form to its virtual |
4281a42e | 3821 | form. |
13d01224 | 3822 | @xref{Target Architecture Definition, , Raw and Virtual Register Representations}. |
9fb4dd36 JB |
3823 | |
3824 | @item REGISTER_CONVERT_TO_RAW(@var{type}, @var{reg}, @var{from}, @var{to}) | |
56caf160 | 3825 | @findex REGISTER_CONVERT_TO_RAW |
9fb4dd36 | 3826 | Convert the value of register @var{reg} from its virtual form to its raw |
4281a42e | 3827 | form. |
13d01224 | 3828 | @xref{Target Architecture Definition, , Raw and Virtual Register Representations}. |
9fb4dd36 | 3829 | |
0ab4b752 MK |
3830 | @item const struct regset *regset_from_core_section (struct gdbarch * @var{gdbarch}, const char * @var{sect_name}, size_t @var{sect_size}) |
3831 | @findex regset_from_core_section | |
3832 | Return the appropriate register set for a core file section with name | |
3833 | @var{sect_name} and size @var{sect_size}. | |
3834 | ||
b0ed3589 | 3835 | @item SOFTWARE_SINGLE_STEP_P() |
56caf160 | 3836 | @findex SOFTWARE_SINGLE_STEP_P |
c906108c | 3837 | Define this as 1 if the target does not have a hardware single-step |
56caf160 | 3838 | mechanism. The macro @code{SOFTWARE_SINGLE_STEP} must also be defined. |
c906108c | 3839 | |
d3e8051b | 3840 | @item SOFTWARE_SINGLE_STEP(@var{signal}, @var{insert_breakpoints_p}) |
56caf160 EZ |
3841 | @findex SOFTWARE_SINGLE_STEP |
3842 | A function that inserts or removes (depending on | |
d3e8051b | 3843 | @var{insert_breakpoints_p}) breakpoints at each possible destinations of |
56caf160 | 3844 | the next instruction. See @file{sparc-tdep.c} and @file{rs6000-tdep.c} |
c906108c SS |
3845 | for examples. |
3846 | ||
da59e081 | 3847 | @item SOFUN_ADDRESS_MAYBE_MISSING |
56caf160 | 3848 | @findex SOFUN_ADDRESS_MAYBE_MISSING |
da59e081 JM |
3849 | Somebody clever observed that, the more actual addresses you have in the |
3850 | debug information, the more time the linker has to spend relocating | |
3851 | them. So whenever there's some other way the debugger could find the | |
3852 | address it needs, you should omit it from the debug info, to make | |
3853 | linking faster. | |
3854 | ||
3855 | @code{SOFUN_ADDRESS_MAYBE_MISSING} indicates that a particular set of | |
3856 | hacks of this sort are in use, affecting @code{N_SO} and @code{N_FUN} | |
3857 | entries in stabs-format debugging information. @code{N_SO} stabs mark | |
3858 | the beginning and ending addresses of compilation units in the text | |
3859 | segment. @code{N_FUN} stabs mark the starts and ends of functions. | |
3860 | ||
3861 | @code{SOFUN_ADDRESS_MAYBE_MISSING} means two things: | |
da59e081 | 3862 | |
56caf160 | 3863 | @itemize @bullet |
da59e081 JM |
3864 | @item |
3865 | @code{N_FUN} stabs have an address of zero. Instead, you should find the | |
3866 | addresses where the function starts by taking the function name from | |
56caf160 EZ |
3867 | the stab, and then looking that up in the minsyms (the |
3868 | linker/assembler symbol table). In other words, the stab has the | |
3869 | name, and the linker/assembler symbol table is the only place that carries | |
da59e081 JM |
3870 | the address. |
3871 | ||
3872 | @item | |
3873 | @code{N_SO} stabs have an address of zero, too. You just look at the | |
3874 | @code{N_FUN} stabs that appear before and after the @code{N_SO} stab, | |
3875 | and guess the starting and ending addresses of the compilation unit from | |
3876 | them. | |
da59e081 JM |
3877 | @end itemize |
3878 | ||
c906108c | 3879 | @item PC_LOAD_SEGMENT |
56caf160 | 3880 | @findex PC_LOAD_SEGMENT |
c906108c SS |
3881 | If defined, print information about the load segment for the program |
3882 | counter. (Defined only for the RS/6000.) | |
3883 | ||
3884 | @item PC_REGNUM | |
56caf160 | 3885 | @findex PC_REGNUM |
c906108c | 3886 | If the program counter is kept in a register, then define this macro to |
cce74817 JM |
3887 | be the number (greater than or equal to zero) of that register. |
3888 | ||
3889 | This should only need to be defined if @code{TARGET_READ_PC} and | |
3890 | @code{TARGET_WRITE_PC} are not defined. | |
c906108c | 3891 | |
2df3850c | 3892 | @item PARM_BOUNDARY |
56caf160 | 3893 | @findex PARM_BOUNDARY |
2df3850c JM |
3894 | If non-zero, round arguments to a boundary of this many bits before |
3895 | pushing them on the stack. | |
3896 | ||
a38c9fe6 MK |
3897 | @item stabs_argument_has_addr (@var{gdbarch}, @var{type}) |
3898 | @findex stabs_argument_has_addr | |
3899 | @findex DEPRECATED_REG_STRUCT_HAS_ADDR | |
3900 | @anchor{stabs_argument_has_addr} Define this to return nonzero if a | |
3901 | function argument of type @var{type} is passed by reference instead of | |
3902 | value. | |
3903 | ||
ee206350 AG |
3904 | This method replaces @code{DEPRECATED_REG_STRUCT_HAS_ADDR} |
3905 | (@pxref{DEPRECATED_REG_STRUCT_HAS_ADDR}). | |
a38c9fe6 | 3906 | |
c906108c | 3907 | @item PROCESS_LINENUMBER_HOOK |
56caf160 | 3908 | @findex PROCESS_LINENUMBER_HOOK |
c906108c SS |
3909 | A hook defined for XCOFF reading. |
3910 | ||
3911 | @item PROLOGUE_FIRSTLINE_OVERLAP | |
56caf160 | 3912 | @findex PROLOGUE_FIRSTLINE_OVERLAP |
c906108c SS |
3913 | (Only used in unsupported Convex configuration.) |
3914 | ||
3915 | @item PS_REGNUM | |
56caf160 | 3916 | @findex PS_REGNUM |
c906108c SS |
3917 | If defined, this is the number of the processor status register. (This |
3918 | definition is only used in generic code when parsing "$ps".) | |
3919 | ||
749b82f6 AC |
3920 | @item DEPRECATED_POP_FRAME |
3921 | @findex DEPRECATED_POP_FRAME | |
3922 | @findex frame_pop | |
3923 | If defined, used by @code{frame_pop} to remove a stack frame. This | |
d3e8051b | 3924 | method has been superseded by generic code. |
c906108c | 3925 | |
d4b6d575 | 3926 | @item push_dummy_call (@var{gdbarch}, @var{function}, @var{regcache}, @var{pc_addr}, @var{nargs}, @var{args}, @var{sp}, @var{struct_return}, @var{struct_addr}) |
b81774d8 AC |
3927 | @findex push_dummy_call |
3928 | @findex DEPRECATED_PUSH_ARGUMENTS. | |
39fe6e80 AC |
3929 | @anchor{push_dummy_call} Define this to push the dummy frame's call to |
3930 | the inferior function onto the stack. In addition to pushing | |
3931 | @var{nargs}, the code should push @var{struct_addr} (when | |
3932 | @var{struct_return}), and the return address (@var{bp_addr}). | |
c906108c | 3933 | |
86fe4aaa | 3934 | @var{function} is a pointer to a @code{struct value}; on architectures that use |
d4b6d575 RC |
3935 | function descriptors, this contains the function descriptor value. |
3936 | ||
b24da7d0 | 3937 | Returns the updated top-of-stack pointer. |
b81774d8 AC |
3938 | |
3939 | This method replaces @code{DEPRECATED_PUSH_ARGUMENTS}. | |
3940 | ||
7043d8dc AC |
3941 | @item CORE_ADDR push_dummy_code (@var{gdbarch}, @var{sp}, @var{funaddr}, @var{using_gcc}, @var{args}, @var{nargs}, @var{value_type}, @var{real_pc}, @var{bp_addr}) |
3942 | @findex push_dummy_code | |
7043d8dc AC |
3943 | @anchor{push_dummy_code} Given a stack based call dummy, push the |
3944 | instruction sequence (including space for a breakpoint) to which the | |
3945 | called function should return. | |
3946 | ||
3947 | Set @var{bp_addr} to the address at which the breakpoint instruction | |
3948 | should be inserted, @var{real_pc} to the resume address when starting | |
3949 | the call sequence, and return the updated inner-most stack address. | |
3950 | ||
3951 | By default, the stack is grown sufficient to hold a frame-aligned | |
3952 | (@pxref{frame_align}) breakpoint, @var{bp_addr} is set to the address | |
3953 | reserved for that breakpoint, and @var{real_pc} set to @var{funaddr}. | |
3954 | ||
434b87dd | 3955 | This method replaces @code{CALL_DUMMY_LOCATION}, |
28954179 | 3956 | @code{DEPRECATED_REGISTER_SIZE}. |
7043d8dc | 3957 | |
56caf160 EZ |
3958 | @item REGISTER_NAME(@var{i}) |
3959 | @findex REGISTER_NAME | |
3960 | Return the name of register @var{i} as a string. May return @code{NULL} | |
3961 | or @code{NUL} to indicate that register @var{i} is not valid. | |
c906108c | 3962 | |
8e823e25 MK |
3963 | @item DEPRECATED_REG_STRUCT_HAS_ADDR (@var{gcc_p}, @var{type}) |
3964 | @findex DEPRECATED_REG_STRUCT_HAS_ADDR | |
a38c9fe6 MK |
3965 | @anchor{DEPRECATED_REG_STRUCT_HAS_ADDR}Define this to return 1 if the |
3966 | given type will be passed by pointer rather than directly. | |
3967 | ||
3968 | This method has been replaced by @code{stabs_argument_has_addr} | |
3969 | (@pxref{stabs_argument_has_addr}). | |
c906108c | 3970 | |
b24da7d0 AC |
3971 | @item SAVE_DUMMY_FRAME_TOS (@var{sp}) |
3972 | @findex SAVE_DUMMY_FRAME_TOS | |
3973 | @anchor{SAVE_DUMMY_FRAME_TOS} Used in @samp{call_function_by_hand} to | |
3974 | notify the target dependent code of the top-of-stack value that will be | |
d3e8051b | 3975 | passed to the inferior code. This is the value of the @code{SP} |
b24da7d0 AC |
3976 | after both the dummy frame and space for parameters/results have been |
3977 | allocated on the stack. @xref{unwind_dummy_id}. | |
43ff13b4 | 3978 | |
c906108c | 3979 | @item SDB_REG_TO_REGNUM |
56caf160 | 3980 | @findex SDB_REG_TO_REGNUM |
25822942 | 3981 | Define this to convert sdb register numbers into @value{GDBN} regnums. If not |
c906108c SS |
3982 | defined, no conversion will be done. |
3983 | ||
963e2bb7 | 3984 | @item enum return_value_convention gdbarch_return_value (struct gdbarch *@var{gdbarch}, struct type *@var{valtype}, struct regcache *@var{regcache}, void *@var{readbuf}, const void *@var{writebuf}) |
92ad9cd9 AC |
3985 | @findex gdbarch_return_value |
3986 | @anchor{gdbarch_return_value} Given a function with a return-value of | |
3987 | type @var{rettype}, return which return-value convention that function | |
3988 | would use. | |
3989 | ||
3990 | @value{GDBN} currently recognizes two function return-value conventions: | |
3991 | @code{RETURN_VALUE_REGISTER_CONVENTION} where the return value is found | |
3992 | in registers; and @code{RETURN_VALUE_STRUCT_CONVENTION} where the return | |
3993 | value is found in memory and the address of that memory location is | |
3994 | passed in as the function's first parameter. | |
3995 | ||
963e2bb7 AC |
3996 | If the register convention is being used, and @var{writebuf} is |
3997 | non-@code{NULL}, also copy the return-value in @var{writebuf} into | |
92ad9cd9 AC |
3998 | @var{regcache}. |
3999 | ||
963e2bb7 | 4000 | If the register convention is being used, and @var{readbuf} is |
92ad9cd9 | 4001 | non-@code{NULL}, also copy the return value from @var{regcache} into |
963e2bb7 | 4002 | @var{readbuf} (@var{regcache} contains a copy of the registers from the |
92ad9cd9 AC |
4003 | just returned function). |
4004 | ||
74055713 | 4005 | @xref{DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS}, for a description of how |
92ad9cd9 AC |
4006 | return-values that use the struct convention are handled. |
4007 | ||
4008 | @emph{Maintainer note: This method replaces separate predicate, extract, | |
4009 | store methods. By having only one method, the logic needed to determine | |
4010 | the return-value convention need only be implemented in one place. If | |
4011 | @value{GDBN} were written in an @sc{oo} language, this method would | |
4012 | instead return an object that knew how to perform the register | |
4013 | return-value extract and store.} | |
4014 | ||
4015 | @emph{Maintainer note: This method does not take a @var{gcc_p} | |
4016 | parameter, and such a parameter should not be added. If an architecture | |
4017 | that requires per-compiler or per-function information be identified, | |
4018 | then the replacement of @var{rettype} with @code{struct value} | |
d3e8051b | 4019 | @var{function} should be pursued.} |
92ad9cd9 AC |
4020 | |
4021 | @emph{Maintainer note: The @var{regcache} parameter limits this methods | |
4022 | to the inner most frame. While replacing @var{regcache} with a | |
4023 | @code{struct frame_info} @var{frame} parameter would remove that | |
4024 | limitation there has yet to be a demonstrated need for such a change.} | |
4025 | ||
c2c6d25f | 4026 | @item SKIP_PERMANENT_BREAKPOINT |
56caf160 | 4027 | @findex SKIP_PERMANENT_BREAKPOINT |
25822942 | 4028 | Advance the inferior's PC past a permanent breakpoint. @value{GDBN} normally |
c2c6d25f JM |
4029 | steps over a breakpoint by removing it, stepping one instruction, and |
4030 | re-inserting the breakpoint. However, permanent breakpoints are | |
4031 | hardwired into the inferior, and can't be removed, so this strategy | |
56caf160 | 4032 | doesn't work. Calling @code{SKIP_PERMANENT_BREAKPOINT} adjusts the processor's |
c2c6d25f JM |
4033 | state so that execution will resume just after the breakpoint. This |
4034 | macro does the right thing even when the breakpoint is in the delay slot | |
4035 | of a branch or jump. | |
4036 | ||
56caf160 EZ |
4037 | @item SKIP_PROLOGUE (@var{pc}) |
4038 | @findex SKIP_PROLOGUE | |
b83266a0 SS |
4039 | A C expression that returns the address of the ``real'' code beyond the |
4040 | function entry prologue found at @var{pc}. | |
c906108c | 4041 | |
56caf160 EZ |
4042 | @item SKIP_TRAMPOLINE_CODE (@var{pc}) |
4043 | @findex SKIP_TRAMPOLINE_CODE | |
c906108c SS |
4044 | If the target machine has trampoline code that sits between callers and |
4045 | the functions being called, then define this macro to return a new PC | |
4046 | that is at the start of the real function. | |
4047 | ||
4048 | @item SP_REGNUM | |
56caf160 | 4049 | @findex SP_REGNUM |
cce74817 | 4050 | If the stack-pointer is kept in a register, then define this macro to be |
6c0e89ed AC |
4051 | the number (greater than or equal to zero) of that register, or -1 if |
4052 | there is no such register. | |
c906108c SS |
4053 | |
4054 | @item STAB_REG_TO_REGNUM | |
56caf160 | 4055 | @findex STAB_REG_TO_REGNUM |
c906108c | 4056 | Define this to convert stab register numbers (as gotten from `r' |
25822942 | 4057 | declarations) into @value{GDBN} regnums. If not defined, no conversion will be |
c906108c SS |
4058 | done. |
4059 | ||
f27dd7fd AC |
4060 | @item DEPRECATED_STACK_ALIGN (@var{addr}) |
4061 | @anchor{DEPRECATED_STACK_ALIGN} | |
4062 | @findex DEPRECATED_STACK_ALIGN | |
790eb8f5 AC |
4063 | Define this to increase @var{addr} so that it meets the alignment |
4064 | requirements for the processor's stack. | |
4065 | ||
4066 | Unlike @ref{frame_align}, this function always adjusts @var{addr} | |
4067 | upwards. | |
4068 | ||
4069 | By default, no stack alignment is performed. | |
c906108c | 4070 | |
56caf160 EZ |
4071 | @item STEP_SKIPS_DELAY (@var{addr}) |
4072 | @findex STEP_SKIPS_DELAY | |
c906108c SS |
4073 | Define this to return true if the address is of an instruction with a |
4074 | delay slot. If a breakpoint has been placed in the instruction's delay | |
25822942 | 4075 | slot, @value{GDBN} will single-step over that instruction before resuming |
c906108c SS |
4076 | normally. Currently only defined for the Mips. |
4077 | ||
ebba8386 | 4078 | @item STORE_RETURN_VALUE (@var{type}, @var{regcache}, @var{valbuf}) |
56caf160 | 4079 | @findex STORE_RETURN_VALUE |
ebba8386 AC |
4080 | A C expression that writes the function return value, found in |
4081 | @var{valbuf}, into the @var{regcache}. @var{type} is the type of the | |
4082 | value that is to be returned. | |
c906108c | 4083 | |
92ad9cd9 AC |
4084 | This method has been deprecated in favour of @code{gdbarch_return_value} |
4085 | (@pxref{gdbarch_return_value}). | |
4086 | ||
c906108c | 4087 | @item SYMBOL_RELOADING_DEFAULT |
56caf160 EZ |
4088 | @findex SYMBOL_RELOADING_DEFAULT |
4089 | The default value of the ``symbol-reloading'' variable. (Never defined in | |
c906108c SS |
4090 | current sources.) |
4091 | ||
c906108c | 4092 | @item TARGET_CHAR_BIT |
56caf160 | 4093 | @findex TARGET_CHAR_BIT |
c906108c SS |
4094 | Number of bits in a char; defaults to 8. |
4095 | ||
c3d3ce5b JB |
4096 | @item TARGET_CHAR_SIGNED |
4097 | @findex TARGET_CHAR_SIGNED | |
4098 | Non-zero if @code{char} is normally signed on this architecture; zero if | |
4099 | it should be unsigned. | |
4100 | ||
4101 | The ISO C standard requires the compiler to treat @code{char} as | |
4102 | equivalent to either @code{signed char} or @code{unsigned char}; any | |
4103 | character in the standard execution set is supposed to be positive. | |
4104 | Most compilers treat @code{char} as signed, but @code{char} is unsigned | |
4105 | on the IBM S/390, RS6000, and PowerPC targets. | |
4106 | ||
c906108c | 4107 | @item TARGET_COMPLEX_BIT |
56caf160 | 4108 | @findex TARGET_COMPLEX_BIT |
c906108c SS |
4109 | Number of bits in a complex number; defaults to @code{2 * TARGET_FLOAT_BIT}. |
4110 | ||
ac9a91a7 JM |
4111 | At present this macro is not used. |
4112 | ||
c906108c | 4113 | @item TARGET_DOUBLE_BIT |
56caf160 | 4114 | @findex TARGET_DOUBLE_BIT |
c906108c SS |
4115 | Number of bits in a double float; defaults to @code{8 * TARGET_CHAR_BIT}. |
4116 | ||
4117 | @item TARGET_DOUBLE_COMPLEX_BIT | |
56caf160 | 4118 | @findex TARGET_DOUBLE_COMPLEX_BIT |
c906108c SS |
4119 | Number of bits in a double complex; defaults to @code{2 * TARGET_DOUBLE_BIT}. |
4120 | ||
ac9a91a7 JM |
4121 | At present this macro is not used. |
4122 | ||
c906108c | 4123 | @item TARGET_FLOAT_BIT |
56caf160 | 4124 | @findex TARGET_FLOAT_BIT |
c906108c SS |
4125 | Number of bits in a float; defaults to @code{4 * TARGET_CHAR_BIT}. |
4126 | ||
4127 | @item TARGET_INT_BIT | |
56caf160 | 4128 | @findex TARGET_INT_BIT |
c906108c SS |
4129 | Number of bits in an integer; defaults to @code{4 * TARGET_CHAR_BIT}. |
4130 | ||
4131 | @item TARGET_LONG_BIT | |
56caf160 | 4132 | @findex TARGET_LONG_BIT |
c906108c SS |
4133 | Number of bits in a long integer; defaults to @code{4 * TARGET_CHAR_BIT}. |
4134 | ||
4135 | @item TARGET_LONG_DOUBLE_BIT | |
56caf160 | 4136 | @findex TARGET_LONG_DOUBLE_BIT |
c906108c SS |
4137 | Number of bits in a long double float; |
4138 | defaults to @code{2 * TARGET_DOUBLE_BIT}. | |
4139 | ||
4140 | @item TARGET_LONG_LONG_BIT | |
56caf160 | 4141 | @findex TARGET_LONG_LONG_BIT |
c906108c SS |
4142 | Number of bits in a long long integer; defaults to @code{2 * TARGET_LONG_BIT}. |
4143 | ||
4144 | @item TARGET_PTR_BIT | |
56caf160 | 4145 | @findex TARGET_PTR_BIT |
c906108c SS |
4146 | Number of bits in a pointer; defaults to @code{TARGET_INT_BIT}. |
4147 | ||
4148 | @item TARGET_SHORT_BIT | |
56caf160 | 4149 | @findex TARGET_SHORT_BIT |
c906108c SS |
4150 | Number of bits in a short integer; defaults to @code{2 * TARGET_CHAR_BIT}. |
4151 | ||
4152 | @item TARGET_READ_PC | |
56caf160 EZ |
4153 | @findex TARGET_READ_PC |
4154 | @itemx TARGET_WRITE_PC (@var{val}, @var{pid}) | |
4155 | @findex TARGET_WRITE_PC | |
0717ae8a | 4156 | @anchor{TARGET_WRITE_PC} |
56caf160 EZ |
4157 | @itemx TARGET_READ_SP |
4158 | @findex TARGET_READ_SP | |
56caf160 EZ |
4159 | @itemx TARGET_READ_FP |
4160 | @findex TARGET_READ_FP | |
56caf160 EZ |
4161 | @findex read_pc |
4162 | @findex write_pc | |
4163 | @findex read_sp | |
56caf160 | 4164 | @findex read_fp |
a9e5fdc2 | 4165 | @anchor{TARGET_READ_SP} These change the behavior of @code{read_pc}, |
8d2c00cb | 4166 | @code{write_pc}, and @code{read_sp}. For most targets, these may be |
9c8dbfa9 AC |
4167 | left undefined. @value{GDBN} will call the read and write register |
4168 | functions with the relevant @code{_REGNUM} argument. | |
c906108c SS |
4169 | |
4170 | These macros are useful when a target keeps one of these registers in a | |
4171 | hard to get at place; for example, part in a segment register and part | |
4172 | in an ordinary register. | |
4173 | ||
a9e5fdc2 AC |
4174 | @xref{unwind_sp}, which replaces @code{TARGET_READ_SP}. |
4175 | ||
56caf160 EZ |
4176 | @item TARGET_VIRTUAL_FRAME_POINTER(@var{pc}, @var{regp}, @var{offsetp}) |
4177 | @findex TARGET_VIRTUAL_FRAME_POINTER | |
0ba6dca9 AC |
4178 | Returns a @code{(register, offset)} pair representing the virtual frame |
4179 | pointer in use at the code address @var{pc}. If virtual frame pointers | |
4180 | are not used, a default definition simply returns | |
4181 | @code{DEPRECATED_FP_REGNUM}, with an offset of zero. | |
c906108c | 4182 | |
9742079a EZ |
4183 | @item TARGET_HAS_HARDWARE_WATCHPOINTS |
4184 | If non-zero, the target has support for hardware-assisted | |
4185 | watchpoints. @xref{Algorithms, watchpoints}, for more details and | |
4186 | other related macros. | |
4187 | ||
7ccaa899 EZ |
4188 | @item TARGET_PRINT_INSN (@var{addr}, @var{info}) |
4189 | @findex TARGET_PRINT_INSN | |
4190 | This is the function used by @value{GDBN} to print an assembly | |
4191 | instruction. It prints the instruction at address @var{addr} in | |
4192 | debugged memory and returns the length of the instruction, in bytes. If | |
4193 | a target doesn't define its own printing routine, it defaults to an | |
d7a27068 AC |
4194 | accessor function for the global pointer |
4195 | @code{deprecated_tm_print_insn}. This usually points to a function in | |
4196 | the @code{opcodes} library (@pxref{Support Libraries, ,Opcodes}). | |
4197 | @var{info} is a structure (of type @code{disassemble_info}) defined in | |
4198 | @file{include/dis-asm.h} used to pass information to the instruction | |
4199 | decoding routine. | |
7ccaa899 | 4200 | |
6314f104 AC |
4201 | @item struct frame_id unwind_dummy_id (struct frame_info *@var{frame}) |
4202 | @findex unwind_dummy_id | |
4203 | @anchor{unwind_dummy_id} Given @var{frame} return a @code{struct | |
4204 | frame_id} that uniquely identifies an inferior function call's dummy | |
b24da7d0 AC |
4205 | frame. The value returned must match the dummy frame stack value |
4206 | previously saved using @code{SAVE_DUMMY_FRAME_TOS}. | |
4207 | @xref{SAVE_DUMMY_FRAME_TOS}. | |
6314f104 | 4208 | |
b5622e8d AC |
4209 | @item DEPRECATED_USE_STRUCT_CONVENTION (@var{gcc_p}, @var{type}) |
4210 | @findex DEPRECATED_USE_STRUCT_CONVENTION | |
c906108c SS |
4211 | If defined, this must be an expression that is nonzero if a value of the |
4212 | given @var{type} being returned from a function must have space | |
4213 | allocated for it on the stack. @var{gcc_p} is true if the function | |
4214 | being considered is known to have been compiled by GCC; this is helpful | |
4215 | for systems where GCC is known to use different calling convention than | |
4216 | other compilers. | |
4217 | ||
92ad9cd9 AC |
4218 | This method has been deprecated in favour of @code{gdbarch_return_value} |
4219 | (@pxref{gdbarch_return_value}). | |
4220 | ||
13d01224 AC |
4221 | @item VALUE_TO_REGISTER(@var{type}, @var{regnum}, @var{from}, @var{to}) |
4222 | @findex VALUE_TO_REGISTER | |
4223 | Convert a value of type @var{type} into the raw contents of register | |
4224 | @var{regnum}'s. | |
4225 | @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. | |
4226 | ||
56caf160 EZ |
4227 | @item VARIABLES_INSIDE_BLOCK (@var{desc}, @var{gcc_p}) |
4228 | @findex VARIABLES_INSIDE_BLOCK | |
c906108c SS |
4229 | For dbx-style debugging information, if the compiler puts variable |
4230 | declarations inside LBRAC/RBRAC blocks, this should be defined to be | |
4231 | nonzero. @var{desc} is the value of @code{n_desc} from the | |
25822942 | 4232 | @code{N_RBRAC} symbol, and @var{gcc_p} is true if @value{GDBN} has noticed the |
c906108c SS |
4233 | presence of either the @code{GCC_COMPILED_SYMBOL} or the |
4234 | @code{GCC2_COMPILED_SYMBOL}. By default, this is 0. | |
4235 | ||
56caf160 EZ |
4236 | @item OS9K_VARIABLES_INSIDE_BLOCK (@var{desc}, @var{gcc_p}) |
4237 | @findex OS9K_VARIABLES_INSIDE_BLOCK | |
c906108c | 4238 | Similarly, for OS/9000. Defaults to 1. |
c906108c SS |
4239 | @end table |
4240 | ||
4241 | Motorola M68K target conditionals. | |
4242 | ||
56caf160 | 4243 | @ftable @code |
c906108c SS |
4244 | @item BPT_VECTOR |
4245 | Define this to be the 4-bit location of the breakpoint trap vector. If | |
4246 | not defined, it will default to @code{0xf}. | |
4247 | ||
4248 | @item REMOTE_BPT_VECTOR | |
4249 | Defaults to @code{1}. | |
a23a7bf1 JB |
4250 | |
4251 | @item NAME_OF_MALLOC | |
4252 | @findex NAME_OF_MALLOC | |
4253 | A string containing the name of the function to call in order to | |
4254 | allocate some memory in the inferior. The default value is "malloc". | |
4255 | ||
56caf160 | 4256 | @end ftable |
c906108c SS |
4257 | |
4258 | @section Adding a New Target | |
4259 | ||
56caf160 | 4260 | @cindex adding a target |
af6c57ea | 4261 | The following files add a target to @value{GDBN}: |
c906108c SS |
4262 | |
4263 | @table @file | |
56caf160 | 4264 | @vindex TDEPFILES |
c906108c SS |
4265 | @item gdb/config/@var{arch}/@var{ttt}.mt |
4266 | Contains a Makefile fragment specific to this target. Specifies what | |
4267 | object files are needed for target @var{ttt}, by defining | |
104c1213 JM |
4268 | @samp{TDEPFILES=@dots{}} and @samp{TDEPLIBS=@dots{}}. Also specifies |
4269 | the header file which describes @var{ttt}, by defining @samp{TM_FILE= | |
4270 | tm-@var{ttt}.h}. | |
4271 | ||
4272 | You can also define @samp{TM_CFLAGS}, @samp{TM_CLIBS}, @samp{TM_CDEPS}, | |
4273 | but these are now deprecated, replaced by autoconf, and may go away in | |
25822942 | 4274 | future versions of @value{GDBN}. |
c906108c | 4275 | |
c906108c SS |
4276 | @item gdb/@var{ttt}-tdep.c |
4277 | Contains any miscellaneous code required for this target machine. On | |
4278 | some machines it doesn't exist at all. Sometimes the macros in | |
4279 | @file{tm-@var{ttt}.h} become very complicated, so they are implemented | |
4280 | as functions here instead, and the macro is simply defined to call the | |
4281 | function. This is vastly preferable, since it is easier to understand | |
4282 | and debug. | |
4283 | ||
af6c57ea AC |
4284 | @item gdb/@var{arch}-tdep.c |
4285 | @itemx gdb/@var{arch}-tdep.h | |
4286 | This often exists to describe the basic layout of the target machine's | |
4287 | processor chip (registers, stack, etc.). If used, it is included by | |
4288 | @file{@var{ttt}-tdep.h}. It can be shared among many targets that use | |
4289 | the same processor. | |
4290 | ||
4291 | @item gdb/config/@var{arch}/tm-@var{ttt}.h | |
4292 | (@file{tm.h} is a link to this file, created by @code{configure}). Contains | |
4293 | macro definitions about the target machine's registers, stack frame | |
4294 | format and instructions. | |
4295 | ||
4296 | New targets do not need this file and should not create it. | |
4297 | ||
c906108c SS |
4298 | @item gdb/config/@var{arch}/tm-@var{arch}.h |
4299 | This often exists to describe the basic layout of the target machine's | |
56caf160 | 4300 | processor chip (registers, stack, etc.). If used, it is included by |
c906108c SS |
4301 | @file{tm-@var{ttt}.h}. It can be shared among many targets that use the |
4302 | same processor. | |
4303 | ||
af6c57ea AC |
4304 | New targets do not need this file and should not create it. |
4305 | ||
c906108c SS |
4306 | @end table |
4307 | ||
4308 | If you are adding a new operating system for an existing CPU chip, add a | |
4309 | @file{config/tm-@var{os}.h} file that describes the operating system | |
4310 | facilities that are unusual (extra symbol table info; the breakpoint | |
56caf160 | 4311 | instruction needed; etc.). Then write a @file{@var{arch}/tm-@var{os}.h} |
c906108c SS |
4312 | that just @code{#include}s @file{tm-@var{arch}.h} and |
4313 | @file{config/tm-@var{os}.h}. | |
4314 | ||
4315 | ||
3352e23e AC |
4316 | @section Converting an existing Target Architecture to Multi-arch |
4317 | @cindex converting targets to multi-arch | |
4318 | ||
4319 | This section describes the current accepted best practice for converting | |
4320 | an existing target architecture to the multi-arch framework. | |
4321 | ||
4322 | The process consists of generating, testing, posting and committing a | |
4323 | sequence of patches. Each patch must contain a single change, for | |
4324 | instance: | |
4325 | ||
4326 | @itemize @bullet | |
4327 | ||
4328 | @item | |
4329 | Directly convert a group of functions into macros (the conversion does | |
4330 | not change the behavior of any of the functions). | |
4331 | ||
4332 | @item | |
4333 | Replace a non-multi-arch with a multi-arch mechanism (e.g., | |
4334 | @code{FRAME_INFO}). | |
4335 | ||
4336 | @item | |
4337 | Enable multi-arch level one. | |
4338 | ||
4339 | @item | |
4340 | Delete one or more files. | |
4341 | ||
4342 | @end itemize | |
4343 | ||
4344 | @noindent | |
4345 | There isn't a size limit on a patch, however, a developer is strongly | |
4346 | encouraged to keep the patch size down. | |
4347 | ||
4348 | Since each patch is well defined, and since each change has been tested | |
4349 | and shows no regressions, the patches are considered @emph{fairly} | |
4350 | obvious. Such patches, when submitted by developers listed in the | |
4351 | @file{MAINTAINERS} file, do not need approval. Occasional steps in the | |
4352 | process may be more complicated and less clear. The developer is | |
4353 | expected to use their judgment and is encouraged to seek advice as | |
4354 | needed. | |
4355 | ||
4356 | @subsection Preparation | |
4357 | ||
4358 | The first step is to establish control. Build (with @option{-Werror} | |
4359 | enabled) and test the target so that there is a baseline against which | |
4360 | the debugger can be compared. | |
4361 | ||
4362 | At no stage can the test results regress or @value{GDBN} stop compiling | |
4363 | with @option{-Werror}. | |
4364 | ||
4365 | @subsection Add the multi-arch initialization code | |
4366 | ||
4367 | The objective of this step is to establish the basic multi-arch | |
4368 | framework. It involves | |
4369 | ||
4370 | @itemize @bullet | |
4371 | ||
4372 | @item | |
4373 | The addition of a @code{@var{arch}_gdbarch_init} function@footnote{The | |
4374 | above is from the original example and uses K&R C. @value{GDBN} | |
4375 | has since converted to ISO C but lets ignore that.} that creates | |
4376 | the architecture: | |
4377 | @smallexample | |
4378 | static struct gdbarch * | |
4379 | d10v_gdbarch_init (info, arches) | |
4380 | struct gdbarch_info info; | |
4381 | struct gdbarch_list *arches; | |
4382 | @{ | |
4383 | struct gdbarch *gdbarch; | |
4384 | /* there is only one d10v architecture */ | |
4385 | if (arches != NULL) | |
4386 | return arches->gdbarch; | |
4387 | gdbarch = gdbarch_alloc (&info, NULL); | |
4388 | return gdbarch; | |
4389 | @} | |
4390 | @end smallexample | |
4391 | @noindent | |
4392 | @emph{} | |
4393 | ||
4394 | @item | |
4395 | A per-architecture dump function to print any architecture specific | |
4396 | information: | |
4397 | @smallexample | |
4398 | static void | |
4399 | mips_dump_tdep (struct gdbarch *current_gdbarch, | |
4400 | struct ui_file *file) | |
4401 | @{ | |
4402 | @dots{} code to print architecture specific info @dots{} | |
4403 | @} | |
4404 | @end smallexample | |
4405 | ||
4406 | @item | |
4407 | A change to @code{_initialize_@var{arch}_tdep} to register this new | |
4408 | architecture: | |
4409 | @smallexample | |
4410 | void | |
4411 | _initialize_mips_tdep (void) | |
4412 | @{ | |
4413 | gdbarch_register (bfd_arch_mips, mips_gdbarch_init, | |
4414 | mips_dump_tdep); | |
4415 | @end smallexample | |
4416 | ||
4417 | @item | |
4418 | Add the macro @code{GDB_MULTI_ARCH}, defined as 0 (zero), to the file@* | |
4419 | @file{config/@var{arch}/tm-@var{arch}.h}. | |
4420 | ||
4421 | @end itemize | |
4422 | ||
4423 | @subsection Update multi-arch incompatible mechanisms | |
4424 | ||
4425 | Some mechanisms do not work with multi-arch. They include: | |
4426 | ||
4427 | @table @code | |
3352e23e | 4428 | @item FRAME_FIND_SAVED_REGS |
f30ee0bc | 4429 | Replaced with @code{DEPRECATED_FRAME_INIT_SAVED_REGS} |
3352e23e AC |
4430 | @end table |
4431 | ||
4432 | @noindent | |
4433 | At this stage you could also consider converting the macros into | |
4434 | functions. | |
4435 | ||
4436 | @subsection Prepare for multi-arch level to one | |
4437 | ||
4438 | Temporally set @code{GDB_MULTI_ARCH} to @code{GDB_MULTI_ARCH_PARTIAL} | |
4439 | and then build and start @value{GDBN} (the change should not be | |
4440 | committed). @value{GDBN} may not build, and once built, it may die with | |
4441 | an internal error listing the architecture methods that must be | |
4442 | provided. | |
4443 | ||
4444 | Fix any build problems (patch(es)). | |
4445 | ||
4446 | Convert all the architecture methods listed, which are only macros, into | |
4447 | functions (patch(es)). | |
4448 | ||
4449 | Update @code{@var{arch}_gdbarch_init} to set all the missing | |
4450 | architecture methods and wrap the corresponding macros in @code{#if | |
4451 | !GDB_MULTI_ARCH} (patch(es)). | |
4452 | ||
4453 | @subsection Set multi-arch level one | |
4454 | ||
4455 | Change the value of @code{GDB_MULTI_ARCH} to GDB_MULTI_ARCH_PARTIAL (a | |
4456 | single patch). | |
4457 | ||
4458 | Any problems with throwing ``the switch'' should have been fixed | |
4459 | already. | |
4460 | ||
4461 | @subsection Convert remaining macros | |
4462 | ||
4463 | Suggest converting macros into functions (and setting the corresponding | |
4464 | architecture method) in small batches. | |
4465 | ||
4466 | @subsection Set multi-arch level to two | |
4467 | ||
4468 | This should go smoothly. | |
4469 | ||
4470 | @subsection Delete the TM file | |
4471 | ||
4472 | The @file{tm-@var{arch}.h} can be deleted. @file{@var{arch}.mt} and | |
4473 | @file{configure.in} updated. | |
4474 | ||
4475 | ||
123dc839 DJ |
4476 | @node Target Descriptions |
4477 | @chapter Target Descriptions | |
4478 | @cindex target descriptions | |
4479 | ||
4480 | The target architecture definition (@pxref{Target Architecture Definition}) | |
4481 | contains @value{GDBN}'s hard-coded knowledge about an architecture. For | |
4482 | some platforms, it is handy to have more flexible knowledge about a specific | |
4483 | instance of the architecture---for instance, a processor or development board. | |
4484 | @dfn{Target descriptions} provide a mechanism for the user to tell @value{GDBN} | |
4485 | more about what their target supports, or for the target to tell @value{GDBN} | |
4486 | directly. | |
4487 | ||
4488 | For details on writing, automatically supplying, and manually selecting | |
4489 | target descriptions, see @ref{Target Descriptions, , , gdb, | |
4490 | Debugging with @value{GDBN}}. This section will cover some related | |
4491 | topics about the @value{GDBN} internals. | |
4492 | ||
4493 | @menu | |
4494 | * Target Descriptions Implementation:: | |
4495 | * Adding Target Described Register Support:: | |
4496 | @end menu | |
4497 | ||
4498 | @node Target Descriptions Implementation | |
4499 | @section Target Descriptions Implementation | |
4500 | @cindex target descriptions, implementation | |
4501 | ||
4502 | Before @value{GDBN} connects to a new target, or runs a new program on | |
4503 | an existing target, it discards any existing target description and | |
4504 | reverts to a default gdbarch. Then, after connecting, it looks for a | |
4505 | new target description by calling @code{target_find_description}. | |
4506 | ||
4507 | A description may come from a user specified file (XML), the remote | |
4508 | @samp{qXfer:features:read} packet (also XML), or from any custom | |
4509 | @code{to_read_description} routine in the target vector. For instance, | |
4510 | the remote target supports guessing whether a MIPS target is 32-bit or | |
4511 | 64-bit based on the size of the @samp{g} packet. | |
4512 | ||
4513 | If any target description is found, @value{GDBN} creates a new gdbarch | |
4514 | incorporating the description by calling @code{gdbarch_update_p}. Any | |
4515 | @samp{<architecture>} element is handled first, to determine which | |
4516 | architecture's gdbarch initialization routine is called to create the | |
4517 | new architecture. Then the initialization routine is called, and has | |
4518 | a chance to adjust the constructed architecture based on the contents | |
4519 | of the target description. For instance, it can recognize any | |
4520 | properties set by a @code{to_read_description} routine. Also | |
4521 | see @ref{Adding Target Described Register Support}. | |
4522 | ||
4523 | @node Adding Target Described Register Support | |
4524 | @section Adding Target Described Register Support | |
4525 | @cindex target descriptions, adding register support | |
4526 | ||
4527 | Target descriptions can report additional registers specific to an | |
4528 | instance of the target. But it takes a little work in the architecture | |
4529 | specific routines to support this. | |
4530 | ||
4531 | A target description must either have no registers or a complete | |
4532 | set---this avoids complexity in trying to merge standard registers | |
4533 | with the target defined registers. It is the architecture's | |
4534 | responsibility to validate that a description with registers has | |
4535 | everything it needs. To keep architecture code simple, the same | |
4536 | mechanism is used to assign fixed internal register numbers to | |
4537 | standard registers. | |
4538 | ||
4539 | If @code{tdesc_has_registers} returns 1, the description contains | |
4540 | registers. The architecture's @code{gdbarch_init} routine should: | |
4541 | ||
4542 | @itemize @bullet | |
4543 | ||
4544 | @item | |
4545 | Call @code{tdesc_data_alloc} to allocate storage, early, before | |
4546 | searching for a matching gdbarch or allocating a new one. | |
4547 | ||
4548 | @item | |
4549 | Use @code{tdesc_find_feature} to locate standard features by name. | |
4550 | ||
4551 | @item | |
4552 | Use @code{tdesc_numbered_register} and @code{tdesc_numbered_register_choices} | |
4553 | to locate the expected registers in the standard features. | |
4554 | ||
4555 | @item | |
4556 | Return @code{NULL} if a required feature is missing, or if any standard | |
4557 | feature is missing expected registers. This will produce a warning that | |
4558 | the description was incomplete. | |
4559 | ||
4560 | @item | |
4561 | Free the allocated data before returning, unless @code{tdesc_use_registers} | |
4562 | is called. | |
4563 | ||
4564 | @item | |
4565 | Call @code{set_gdbarch_num_regs} as usual, with a number higher than any | |
4566 | fixed number passed to @code{tdesc_numbered_register}. | |
4567 | ||
4568 | @item | |
4569 | Call @code{tdesc_use_registers} after creating a new gdbarch, before | |
4570 | returning it. | |
4571 | ||
4572 | @end itemize | |
4573 | ||
4574 | After @code{tdesc_use_registers} has been called, the architecture's | |
4575 | @code{register_name}, @code{register_type}, and @code{register_reggroup_p} | |
4576 | routines will not be called; that information will be taken from | |
4577 | the target description. @code{num_regs} may be increased to account | |
4578 | for any additional registers in the description. | |
4579 | ||
4580 | Pseudo-registers require some extra care: | |
4581 | ||
4582 | @itemize @bullet | |
4583 | ||
4584 | @item | |
4585 | Using @code{tdesc_numbered_register} allows the architecture to give | |
4586 | constant register numbers to standard architectural registers, e.g.@: | |
4587 | as an @code{enum} in @file{@var{arch}-tdep.h}. But because | |
4588 | pseudo-registers are always numbered above @code{num_regs}, | |
4589 | which may be increased by the description, constant numbers | |
4590 | can not be used for pseudos. They must be numbered relative to | |
4591 | @code{num_regs} instead. | |
4592 | ||
4593 | @item | |
4594 | The description will not describe pseudo-registers, so the | |
4595 | architecture must call @code{set_tdesc_pseudo_register_name}, | |
4596 | @code{set_tdesc_pseudo_register_type}, and | |
4597 | @code{set_tdesc_pseudo_register_reggroup_p} to supply routines | |
4598 | describing pseudo registers. These routines will be passed | |
4599 | internal register numbers, so the same routines used for the | |
4600 | gdbarch equivalents are usually suitable. | |
4601 | ||
4602 | @end itemize | |
4603 | ||
4604 | ||
c906108c SS |
4605 | @node Target Vector Definition |
4606 | ||
4607 | @chapter Target Vector Definition | |
56caf160 | 4608 | @cindex target vector |
c906108c | 4609 | |
56caf160 EZ |
4610 | The target vector defines the interface between @value{GDBN}'s |
4611 | abstract handling of target systems, and the nitty-gritty code that | |
4612 | actually exercises control over a process or a serial port. | |
4613 | @value{GDBN} includes some 30-40 different target vectors; however, | |
4614 | each configuration of @value{GDBN} includes only a few of them. | |
c906108c | 4615 | |
52bb452f DJ |
4616 | @menu |
4617 | * Managing Execution State:: | |
4618 | * Existing Targets:: | |
4619 | @end menu | |
4620 | ||
4621 | @node Managing Execution State | |
4622 | @section Managing Execution State | |
4623 | @cindex execution state | |
4624 | ||
4625 | A target vector can be completely inactive (not pushed on the target | |
4626 | stack), active but not running (pushed, but not connected to a fully | |
4627 | manifested inferior), or completely active (pushed, with an accessible | |
4628 | inferior). Most targets are only completely inactive or completely | |
d3e8051b | 4629 | active, but some support persistent connections to a target even |
52bb452f DJ |
4630 | when the target has exited or not yet started. |
4631 | ||
4632 | For example, connecting to the simulator using @code{target sim} does | |
4633 | not create a running program. Neither registers nor memory are | |
4634 | accessible until @code{run}. Similarly, after @code{kill}, the | |
4635 | program can not continue executing. But in both cases @value{GDBN} | |
4636 | remains connected to the simulator, and target-specific commands | |
4637 | are directed to the simulator. | |
4638 | ||
4639 | A target which only supports complete activation should push itself | |
4640 | onto the stack in its @code{to_open} routine (by calling | |
4641 | @code{push_target}), and unpush itself from the stack in its | |
4642 | @code{to_mourn_inferior} routine (by calling @code{unpush_target}). | |
4643 | ||
4644 | A target which supports both partial and complete activation should | |
4645 | still call @code{push_target} in @code{to_open}, but not call | |
4646 | @code{unpush_target} in @code{to_mourn_inferior}. Instead, it should | |
4647 | call either @code{target_mark_running} or @code{target_mark_exited} | |
4648 | in its @code{to_open}, depending on whether the target is fully active | |
4649 | after connection. It should also call @code{target_mark_running} any | |
4650 | time the inferior becomes fully active (e.g.@: in | |
4651 | @code{to_create_inferior} and @code{to_attach}), and | |
4652 | @code{target_mark_exited} when the inferior becomes inactive (in | |
4653 | @code{to_mourn_inferior}). The target should also make sure to call | |
4654 | @code{target_mourn_inferior} from its @code{to_kill}, to return the | |
4655 | target to inactive state. | |
4656 | ||
4657 | @node Existing Targets | |
4658 | @section Existing Targets | |
4659 | @cindex targets | |
4660 | ||
4661 | @subsection File Targets | |
c906108c SS |
4662 | |
4663 | Both executables and core files have target vectors. | |
4664 | ||
52bb452f | 4665 | @subsection Standard Protocol and Remote Stubs |
c906108c | 4666 | |
56caf160 EZ |
4667 | @value{GDBN}'s file @file{remote.c} talks a serial protocol to code |
4668 | that runs in the target system. @value{GDBN} provides several sample | |
4669 | @dfn{stubs} that can be integrated into target programs or operating | |
4670 | systems for this purpose; they are named @file{*-stub.c}. | |
c906108c | 4671 | |
56caf160 EZ |
4672 | The @value{GDBN} user's manual describes how to put such a stub into |
4673 | your target code. What follows is a discussion of integrating the | |
4674 | SPARC stub into a complicated operating system (rather than a simple | |
4675 | program), by Stu Grossman, the author of this stub. | |
c906108c SS |
4676 | |
4677 | The trap handling code in the stub assumes the following upon entry to | |
56caf160 | 4678 | @code{trap_low}: |
c906108c SS |
4679 | |
4680 | @enumerate | |
56caf160 EZ |
4681 | @item |
4682 | %l1 and %l2 contain pc and npc respectively at the time of the trap; | |
c906108c | 4683 | |
56caf160 EZ |
4684 | @item |
4685 | traps are disabled; | |
c906108c | 4686 | |
56caf160 EZ |
4687 | @item |
4688 | you are in the correct trap window. | |
c906108c SS |
4689 | @end enumerate |
4690 | ||
4691 | As long as your trap handler can guarantee those conditions, then there | |
56caf160 | 4692 | is no reason why you shouldn't be able to ``share'' traps with the stub. |
c906108c SS |
4693 | The stub has no requirement that it be jumped to directly from the |
4694 | hardware trap vector. That is why it calls @code{exceptionHandler()}, | |
4695 | which is provided by the external environment. For instance, this could | |
56caf160 | 4696 | set up the hardware traps to actually execute code which calls the stub |
c906108c SS |
4697 | first, and then transfers to its own trap handler. |
4698 | ||
4699 | For the most point, there probably won't be much of an issue with | |
56caf160 | 4700 | ``sharing'' traps, as the traps we use are usually not used by the kernel, |
c906108c SS |
4701 | and often indicate unrecoverable error conditions. Anyway, this is all |
4702 | controlled by a table, and is trivial to modify. The most important | |
4703 | trap for us is for @code{ta 1}. Without that, we can't single step or | |
4704 | do breakpoints. Everything else is unnecessary for the proper operation | |
4705 | of the debugger/stub. | |
4706 | ||
4707 | From reading the stub, it's probably not obvious how breakpoints work. | |
25822942 | 4708 | They are simply done by deposit/examine operations from @value{GDBN}. |
c906108c | 4709 | |
52bb452f | 4710 | @subsection ROM Monitor Interface |
c906108c | 4711 | |
52bb452f | 4712 | @subsection Custom Protocols |
c906108c | 4713 | |
52bb452f | 4714 | @subsection Transport Layer |
c906108c | 4715 | |
52bb452f | 4716 | @subsection Builtin Simulator |
c906108c SS |
4717 | |
4718 | ||
4719 | @node Native Debugging | |
4720 | ||
4721 | @chapter Native Debugging | |
56caf160 | 4722 | @cindex native debugging |
c906108c | 4723 | |
25822942 | 4724 | Several files control @value{GDBN}'s configuration for native support: |
c906108c SS |
4725 | |
4726 | @table @file | |
56caf160 | 4727 | @vindex NATDEPFILES |
c906108c | 4728 | @item gdb/config/@var{arch}/@var{xyz}.mh |
7fd60527 | 4729 | Specifies Makefile fragments needed by a @emph{native} configuration on |
c906108c SS |
4730 | machine @var{xyz}. In particular, this lists the required |
4731 | native-dependent object files, by defining @samp{NATDEPFILES=@dots{}}. | |
4732 | Also specifies the header file which describes native support on | |
4733 | @var{xyz}, by defining @samp{NAT_FILE= nm-@var{xyz}.h}. You can also | |
4734 | define @samp{NAT_CFLAGS}, @samp{NAT_ADD_FILES}, @samp{NAT_CLIBS}, | |
4735 | @samp{NAT_CDEPS}, etc.; see @file{Makefile.in}. | |
4736 | ||
7fd60527 AC |
4737 | @emph{Maintainer's note: The @file{.mh} suffix is because this file |
4738 | originally contained @file{Makefile} fragments for hosting @value{GDBN} | |
4739 | on machine @var{xyz}. While the file is no longer used for this | |
937f164b | 4740 | purpose, the @file{.mh} suffix remains. Perhaps someone will |
7fd60527 AC |
4741 | eventually rename these fragments so that they have a @file{.mn} |
4742 | suffix.} | |
4743 | ||
c906108c | 4744 | @item gdb/config/@var{arch}/nm-@var{xyz}.h |
56caf160 | 4745 | (@file{nm.h} is a link to this file, created by @code{configure}). Contains C |
c906108c SS |
4746 | macro definitions describing the native system environment, such as |
4747 | child process control and core file support. | |
4748 | ||
4749 | @item gdb/@var{xyz}-nat.c | |
4750 | Contains any miscellaneous C code required for this native support of | |
4751 | this machine. On some machines it doesn't exist at all. | |
c906108c SS |
4752 | @end table |
4753 | ||
4754 | There are some ``generic'' versions of routines that can be used by | |
4755 | various systems. These can be customized in various ways by macros | |
4756 | defined in your @file{nm-@var{xyz}.h} file. If these routines work for | |
4757 | the @var{xyz} host, you can just include the generic file's name (with | |
4758 | @samp{.o}, not @samp{.c}) in @code{NATDEPFILES}. | |
4759 | ||
4760 | Otherwise, if your machine needs custom support routines, you will need | |
4761 | to write routines that perform the same functions as the generic file. | |
56caf160 | 4762 | Put them into @file{@var{xyz}-nat.c}, and put @file{@var{xyz}-nat.o} |
c906108c SS |
4763 | into @code{NATDEPFILES}. |
4764 | ||
4765 | @table @file | |
c906108c SS |
4766 | @item inftarg.c |
4767 | This contains the @emph{target_ops vector} that supports Unix child | |
4768 | processes on systems which use ptrace and wait to control the child. | |
4769 | ||
4770 | @item procfs.c | |
4771 | This contains the @emph{target_ops vector} that supports Unix child | |
4772 | processes on systems which use /proc to control the child. | |
4773 | ||
4774 | @item fork-child.c | |
56caf160 EZ |
4775 | This does the low-level grunge that uses Unix system calls to do a ``fork |
4776 | and exec'' to start up a child process. | |
c906108c SS |
4777 | |
4778 | @item infptrace.c | |
4779 | This is the low level interface to inferior processes for systems using | |
4780 | the Unix @code{ptrace} call in a vanilla way. | |
c906108c SS |
4781 | @end table |
4782 | ||
4783 | @section Native core file Support | |
56caf160 | 4784 | @cindex native core files |
c906108c SS |
4785 | |
4786 | @table @file | |
56caf160 | 4787 | @findex fetch_core_registers |
c906108c SS |
4788 | @item core-aout.c::fetch_core_registers() |
4789 | Support for reading registers out of a core file. This routine calls | |
4790 | @code{register_addr()}, see below. Now that BFD is used to read core | |
4791 | files, virtually all machines should use @code{core-aout.c}, and should | |
4792 | just provide @code{fetch_core_registers} in @code{@var{xyz}-nat.c} (or | |
4793 | @code{REGISTER_U_ADDR} in @code{nm-@var{xyz}.h}). | |
4794 | ||
4795 | @item core-aout.c::register_addr() | |
4796 | If your @code{nm-@var{xyz}.h} file defines the macro | |
4797 | @code{REGISTER_U_ADDR(addr, blockend, regno)}, it should be defined to | |
25822942 | 4798 | set @code{addr} to the offset within the @samp{user} struct of @value{GDBN} |
c906108c SS |
4799 | register number @code{regno}. @code{blockend} is the offset within the |
4800 | ``upage'' of @code{u.u_ar0}. If @code{REGISTER_U_ADDR} is defined, | |
4801 | @file{core-aout.c} will define the @code{register_addr()} function and | |
4802 | use the macro in it. If you do not define @code{REGISTER_U_ADDR}, but | |
4803 | you are using the standard @code{fetch_core_registers()}, you will need | |
4804 | to define your own version of @code{register_addr()}, put it into your | |
4805 | @code{@var{xyz}-nat.c} file, and be sure @code{@var{xyz}-nat.o} is in | |
4806 | the @code{NATDEPFILES} list. If you have your own | |
4807 | @code{fetch_core_registers()}, you may not need a separate | |
4808 | @code{register_addr()}. Many custom @code{fetch_core_registers()} | |
4809 | implementations simply locate the registers themselves.@refill | |
c906108c SS |
4810 | @end table |
4811 | ||
25822942 | 4812 | When making @value{GDBN} run native on a new operating system, to make it |
c906108c SS |
4813 | possible to debug core files, you will need to either write specific |
4814 | code for parsing your OS's core files, or customize | |
4815 | @file{bfd/trad-core.c}. First, use whatever @code{#include} files your | |
4816 | machine uses to define the struct of registers that is accessible | |
4817 | (possibly in the u-area) in a core file (rather than | |
4818 | @file{machine/reg.h}), and an include file that defines whatever header | |
c1468174 | 4819 | exists on a core file (e.g., the u-area or a @code{struct core}). Then |
56caf160 | 4820 | modify @code{trad_unix_core_file_p} to use these values to set up the |
c906108c SS |
4821 | section information for the data segment, stack segment, any other |
4822 | segments in the core file (perhaps shared library contents or control | |
4823 | information), ``registers'' segment, and if there are two discontiguous | |
c1468174 | 4824 | sets of registers (e.g., integer and float), the ``reg2'' segment. This |
c906108c SS |
4825 | section information basically delimits areas in the core file in a |
4826 | standard way, which the section-reading routines in BFD know how to seek | |
4827 | around in. | |
4828 | ||
25822942 | 4829 | Then back in @value{GDBN}, you need a matching routine called |
56caf160 | 4830 | @code{fetch_core_registers}. If you can use the generic one, it's in |
c906108c SS |
4831 | @file{core-aout.c}; if not, it's in your @file{@var{xyz}-nat.c} file. |
4832 | It will be passed a char pointer to the entire ``registers'' segment, | |
4833 | its length, and a zero; or a char pointer to the entire ``regs2'' | |
4834 | segment, its length, and a 2. The routine should suck out the supplied | |
25822942 | 4835 | register values and install them into @value{GDBN}'s ``registers'' array. |
c906108c SS |
4836 | |
4837 | If your system uses @file{/proc} to control processes, and uses ELF | |
4838 | format core files, then you may be able to use the same routines for | |
4839 | reading the registers out of processes and out of core files. | |
4840 | ||
4841 | @section ptrace | |
4842 | ||
4843 | @section /proc | |
4844 | ||
4845 | @section win32 | |
4846 | ||
4847 | @section shared libraries | |
4848 | ||
4849 | @section Native Conditionals | |
56caf160 | 4850 | @cindex native conditionals |
c906108c | 4851 | |
56caf160 EZ |
4852 | When @value{GDBN} is configured and compiled, various macros are |
4853 | defined or left undefined, to control compilation when the host and | |
4854 | target systems are the same. These macros should be defined (or left | |
4855 | undefined) in @file{nm-@var{system}.h}. | |
c906108c | 4856 | |
1f6d4158 AC |
4857 | @table @code |
4858 | ||
c906108c | 4859 | @item CHILD_PREPARE_TO_STORE |
56caf160 | 4860 | @findex CHILD_PREPARE_TO_STORE |
c906108c SS |
4861 | If the machine stores all registers at once in the child process, then |
4862 | define this to ensure that all values are correct. This usually entails | |
4863 | a read from the child. | |
4864 | ||
4865 | [Note that this is incorrectly defined in @file{xm-@var{system}.h} files | |
4866 | currently.] | |
4867 | ||
4868 | @item FETCH_INFERIOR_REGISTERS | |
56caf160 | 4869 | @findex FETCH_INFERIOR_REGISTERS |
c906108c SS |
4870 | Define this if the native-dependent code will provide its own routines |
4871 | @code{fetch_inferior_registers} and @code{store_inferior_registers} in | |
56caf160 | 4872 | @file{@var{host}-nat.c}. If this symbol is @emph{not} defined, and |
c906108c SS |
4873 | @file{infptrace.c} is included in this configuration, the default |
4874 | routines in @file{infptrace.c} are used for these functions. | |
4875 | ||
c906108c | 4876 | @item FP0_REGNUM |
56caf160 | 4877 | @findex FP0_REGNUM |
c906108c SS |
4878 | This macro is normally defined to be the number of the first floating |
4879 | point register, if the machine has such registers. As such, it would | |
56caf160 | 4880 | appear only in target-specific code. However, @file{/proc} support uses this |
c906108c SS |
4881 | to decide whether floats are in use on this target. |
4882 | ||
4883 | @item GET_LONGJMP_TARGET | |
56caf160 | 4884 | @findex GET_LONGJMP_TARGET |
c906108c SS |
4885 | For most machines, this is a target-dependent parameter. On the |
4886 | DECstation and the Iris, this is a native-dependent parameter, since | |
56caf160 | 4887 | @file{setjmp.h} is needed to define it. |
c906108c | 4888 | |
56caf160 | 4889 | This macro determines the target PC address that @code{longjmp} will jump to, |
c906108c | 4890 | assuming that we have just stopped at a longjmp breakpoint. It takes a |
56caf160 | 4891 | @code{CORE_ADDR *} as argument, and stores the target PC value through this |
c906108c SS |
4892 | pointer. It examines the current state of the machine as needed. |
4893 | ||
9742079a EZ |
4894 | @item I386_USE_GENERIC_WATCHPOINTS |
4895 | An x86-based machine can define this to use the generic x86 watchpoint | |
4896 | support; see @ref{Algorithms, I386_USE_GENERIC_WATCHPOINTS}. | |
4897 | ||
c906108c | 4898 | @item KERNEL_U_ADDR |
56caf160 | 4899 | @findex KERNEL_U_ADDR |
c906108c | 4900 | Define this to the address of the @code{u} structure (the ``user |
25822942 | 4901 | struct'', also known as the ``u-page'') in kernel virtual memory. @value{GDBN} |
c906108c SS |
4902 | needs to know this so that it can subtract this address from absolute |
4903 | addresses in the upage, that are obtained via ptrace or from core files. | |
4904 | On systems that don't need this value, set it to zero. | |
4905 | ||
c906108c | 4906 | @item KERNEL_U_ADDR_HPUX |
56caf160 | 4907 | @findex KERNEL_U_ADDR_HPUX |
25822942 | 4908 | Define this to cause @value{GDBN} to determine the address of @code{u} at |
c906108c SS |
4909 | runtime, by using HP-style @code{nlist} on the kernel's image in the |
4910 | root directory. | |
4911 | ||
4912 | @item ONE_PROCESS_WRITETEXT | |
56caf160 | 4913 | @findex ONE_PROCESS_WRITETEXT |
c906108c SS |
4914 | Define this to be able to, when a breakpoint insertion fails, warn the |
4915 | user that another process may be running with the same executable. | |
4916 | ||
4917 | @item PROC_NAME_FMT | |
56caf160 | 4918 | @findex PROC_NAME_FMT |
c906108c SS |
4919 | Defines the format for the name of a @file{/proc} device. Should be |
4920 | defined in @file{nm.h} @emph{only} in order to override the default | |
4921 | definition in @file{procfs.c}. | |
4922 | ||
c906108c | 4923 | @item REGISTER_U_ADDR |
56caf160 | 4924 | @findex REGISTER_U_ADDR |
c906108c SS |
4925 | Defines the offset of the registers in the ``u area''. |
4926 | ||
4927 | @item SHELL_COMMAND_CONCAT | |
56caf160 | 4928 | @findex SHELL_COMMAND_CONCAT |
c906108c SS |
4929 | If defined, is a string to prefix on the shell command used to start the |
4930 | inferior. | |
4931 | ||
4932 | @item SHELL_FILE | |
56caf160 | 4933 | @findex SHELL_FILE |
c906108c SS |
4934 | If defined, this is the name of the shell to use to run the inferior. |
4935 | Defaults to @code{"/bin/sh"}. | |
4936 | ||
990f9fe3 | 4937 | @item SOLIB_ADD (@var{filename}, @var{from_tty}, @var{targ}, @var{readsyms}) |
56caf160 | 4938 | @findex SOLIB_ADD |
c906108c | 4939 | Define this to expand into an expression that will cause the symbols in |
990f9fe3 FF |
4940 | @var{filename} to be added to @value{GDBN}'s symbol table. If |
4941 | @var{readsyms} is zero symbols are not read but any necessary low level | |
4942 | processing for @var{filename} is still done. | |
c906108c SS |
4943 | |
4944 | @item SOLIB_CREATE_INFERIOR_HOOK | |
56caf160 | 4945 | @findex SOLIB_CREATE_INFERIOR_HOOK |
c906108c SS |
4946 | Define this to expand into any shared-library-relocation code that you |
4947 | want to be run just after the child process has been forked. | |
4948 | ||
4949 | @item START_INFERIOR_TRAPS_EXPECTED | |
56caf160 EZ |
4950 | @findex START_INFERIOR_TRAPS_EXPECTED |
4951 | When starting an inferior, @value{GDBN} normally expects to trap | |
4952 | twice; once when | |
c906108c SS |
4953 | the shell execs, and once when the program itself execs. If the actual |
4954 | number of traps is something other than 2, then define this macro to | |
4955 | expand into the number expected. | |
4956 | ||
c906108c | 4957 | @item USE_PROC_FS |
56caf160 | 4958 | @findex USE_PROC_FS |
c906108c | 4959 | This determines whether small routines in @file{*-tdep.c}, which |
56caf160 EZ |
4960 | translate register values between @value{GDBN}'s internal |
4961 | representation and the @file{/proc} representation, are compiled. | |
c906108c SS |
4962 | |
4963 | @item U_REGS_OFFSET | |
56caf160 | 4964 | @findex U_REGS_OFFSET |
c906108c SS |
4965 | This is the offset of the registers in the upage. It need only be |
4966 | defined if the generic ptrace register access routines in | |
4967 | @file{infptrace.c} are being used (that is, @file{infptrace.c} is | |
4968 | configured in, and @code{FETCH_INFERIOR_REGISTERS} is not defined). If | |
4969 | the default value from @file{infptrace.c} is good enough, leave it | |
4970 | undefined. | |
4971 | ||
4972 | The default value means that u.u_ar0 @emph{points to} the location of | |
4973 | the registers. I'm guessing that @code{#define U_REGS_OFFSET 0} means | |
56caf160 | 4974 | that @code{u.u_ar0} @emph{is} the location of the registers. |
c906108c SS |
4975 | |
4976 | @item CLEAR_SOLIB | |
56caf160 EZ |
4977 | @findex CLEAR_SOLIB |
4978 | See @file{objfiles.c}. | |
c906108c SS |
4979 | |
4980 | @item DEBUG_PTRACE | |
56caf160 EZ |
4981 | @findex DEBUG_PTRACE |
4982 | Define this to debug @code{ptrace} calls. | |
c906108c SS |
4983 | @end table |
4984 | ||
4985 | ||
4986 | @node Support Libraries | |
4987 | ||
4988 | @chapter Support Libraries | |
4989 | ||
4990 | @section BFD | |
56caf160 | 4991 | @cindex BFD library |
c906108c | 4992 | |
25822942 | 4993 | BFD provides support for @value{GDBN} in several ways: |
c906108c SS |
4994 | |
4995 | @table @emph | |
c906108c SS |
4996 | @item identifying executable and core files |
4997 | BFD will identify a variety of file types, including a.out, coff, and | |
4998 | several variants thereof, as well as several kinds of core files. | |
4999 | ||
5000 | @item access to sections of files | |
5001 | BFD parses the file headers to determine the names, virtual addresses, | |
5002 | sizes, and file locations of all the various named sections in files | |
56caf160 EZ |
5003 | (such as the text section or the data section). @value{GDBN} simply |
5004 | calls BFD to read or write section @var{x} at byte offset @var{y} for | |
5005 | length @var{z}. | |
c906108c SS |
5006 | |
5007 | @item specialized core file support | |
5008 | BFD provides routines to determine the failing command name stored in a | |
5009 | core file, the signal with which the program failed, and whether a core | |
56caf160 | 5010 | file matches (i.e.@: could be a core dump of) a particular executable |
c906108c SS |
5011 | file. |
5012 | ||
5013 | @item locating the symbol information | |
25822942 DB |
5014 | @value{GDBN} uses an internal interface of BFD to determine where to find the |
5015 | symbol information in an executable file or symbol-file. @value{GDBN} itself | |
c906108c | 5016 | handles the reading of symbols, since BFD does not ``understand'' debug |
25822942 | 5017 | symbols, but @value{GDBN} uses BFD's cached information to find the symbols, |
c906108c | 5018 | string table, etc. |
c906108c SS |
5019 | @end table |
5020 | ||
5021 | @section opcodes | |
56caf160 | 5022 | @cindex opcodes library |
c906108c | 5023 | |
25822942 | 5024 | The opcodes library provides @value{GDBN}'s disassembler. (It's a separate |
c906108c SS |
5025 | library because it's also used in binutils, for @file{objdump}). |
5026 | ||
5027 | @section readline | |
86f04699 EZ |
5028 | @cindex readline library |
5029 | The @code{readline} library provides a set of functions for use by applications | |
5030 | that allow users to edit command lines as they are typed in. | |
c906108c SS |
5031 | |
5032 | @section libiberty | |
1eb288ea EZ |
5033 | @cindex @code{libiberty} library |
5034 | ||
5035 | The @code{libiberty} library provides a set of functions and features | |
5036 | that integrate and improve on functionality found in modern operating | |
5037 | systems. Broadly speaking, such features can be divided into three | |
5038 | groups: supplemental functions (functions that may be missing in some | |
5039 | environments and operating systems), replacement functions (providing | |
5040 | a uniform and easier to use interface for commonly used standard | |
5041 | functions), and extensions (which provide additional functionality | |
5042 | beyond standard functions). | |
5043 | ||
5044 | @value{GDBN} uses various features provided by the @code{libiberty} | |
5045 | library, for instance the C@t{++} demangler, the @acronym{IEEE} | |
5046 | floating format support functions, the input options parser | |
5047 | @samp{getopt}, the @samp{obstack} extension, and other functions. | |
5048 | ||
5049 | @subsection @code{obstacks} in @value{GDBN} | |
5050 | @cindex @code{obstacks} | |
5051 | ||
5052 | The obstack mechanism provides a convenient way to allocate and free | |
5053 | chunks of memory. Each obstack is a pool of memory that is managed | |
5054 | like a stack. Objects (of any nature, size and alignment) are | |
5055 | allocated and freed in a @acronym{LIFO} fashion on an obstack (see | |
d3e8051b | 5056 | @code{libiberty}'s documentation for a more detailed explanation of |
1eb288ea EZ |
5057 | @code{obstacks}). |
5058 | ||
5059 | The most noticeable use of the @code{obstacks} in @value{GDBN} is in | |
5060 | object files. There is an obstack associated with each internal | |
5061 | representation of an object file. Lots of things get allocated on | |
5062 | these @code{obstacks}: dictionary entries, blocks, blockvectors, | |
5063 | symbols, minimal symbols, types, vectors of fundamental types, class | |
5064 | fields of types, object files section lists, object files section | |
d3e8051b | 5065 | offset lists, line tables, symbol tables, partial symbol tables, |
1eb288ea EZ |
5066 | string tables, symbol table private data, macros tables, debug |
5067 | information sections and entries, import and export lists (som), | |
5068 | unwind information (hppa), dwarf2 location expressions data. Plus | |
5069 | various strings such as directory names strings, debug format strings, | |
5070 | names of types. | |
5071 | ||
5072 | An essential and convenient property of all data on @code{obstacks} is | |
5073 | that memory for it gets allocated (with @code{obstack_alloc}) at | |
d3e8051b | 5074 | various times during a debugging session, but it is released all at |
1eb288ea EZ |
5075 | once using the @code{obstack_free} function. The @code{obstack_free} |
5076 | function takes a pointer to where in the stack it must start the | |
5077 | deletion from (much like the cleanup chains have a pointer to where to | |
5078 | start the cleanups). Because of the stack like structure of the | |
5079 | @code{obstacks}, this allows to free only a top portion of the | |
5080 | obstack. There are a few instances in @value{GDBN} where such thing | |
5081 | happens. Calls to @code{obstack_free} are done after some local data | |
5082 | is allocated to the obstack. Only the local data is deleted from the | |
5083 | obstack. Of course this assumes that nothing between the | |
5084 | @code{obstack_alloc} and the @code{obstack_free} allocates anything | |
5085 | else on the same obstack. For this reason it is best and safest to | |
5086 | use temporary @code{obstacks}. | |
5087 | ||
5088 | Releasing the whole obstack is also not safe per se. It is safe only | |
5089 | under the condition that we know the @code{obstacks} memory is no | |
5090 | longer needed. In @value{GDBN} we get rid of the @code{obstacks} only | |
5091 | when we get rid of the whole objfile(s), for instance upon reading a | |
5092 | new symbol file. | |
c906108c SS |
5093 | |
5094 | @section gnu-regex | |
56caf160 | 5095 | @cindex regular expressions library |
c906108c SS |
5096 | |
5097 | Regex conditionals. | |
5098 | ||
5099 | @table @code | |
c906108c SS |
5100 | @item C_ALLOCA |
5101 | ||
5102 | @item NFAILURES | |
5103 | ||
5104 | @item RE_NREGS | |
5105 | ||
5106 | @item SIGN_EXTEND_CHAR | |
5107 | ||
5108 | @item SWITCH_ENUM_BUG | |
5109 | ||
5110 | @item SYNTAX_TABLE | |
5111 | ||
5112 | @item Sword | |
5113 | ||
5114 | @item sparc | |
c906108c SS |
5115 | @end table |
5116 | ||
350da6ee DJ |
5117 | @section Array Containers |
5118 | @cindex Array Containers | |
5119 | @cindex VEC | |
5120 | ||
5121 | Often it is necessary to manipulate a dynamic array of a set of | |
5122 | objects. C forces some bookkeeping on this, which can get cumbersome | |
d3e8051b | 5123 | and repetitive. The @file{vec.h} file contains macros for defining |
350da6ee DJ |
5124 | and using a typesafe vector type. The functions defined will be |
5125 | inlined when compiling, and so the abstraction cost should be zero. | |
5126 | Domain checks are added to detect programming errors. | |
5127 | ||
5128 | An example use would be an array of symbols or section information. | |
5129 | The array can be grown as symbols are read in (or preallocated), and | |
5130 | the accessor macros provided keep care of all the necessary | |
5131 | bookkeeping. Because the arrays are type safe, there is no danger of | |
5132 | accidentally mixing up the contents. Think of these as C++ templates, | |
5133 | but implemented in C. | |
5134 | ||
5135 | Because of the different behavior of structure objects, scalar objects | |
5136 | and of pointers, there are three flavors of vector, one for each of | |
5137 | these variants. Both the structure object and pointer variants pass | |
5138 | pointers to objects around --- in the former case the pointers are | |
5139 | stored into the vector and in the latter case the pointers are | |
5140 | dereferenced and the objects copied into the vector. The scalar | |
5141 | object variant is suitable for @code{int}-like objects, and the vector | |
5142 | elements are returned by value. | |
5143 | ||
5144 | There are both @code{index} and @code{iterate} accessors. The iterator | |
5145 | returns a boolean iteration condition and updates the iteration | |
5146 | variable passed by reference. Because the iterator will be inlined, | |
5147 | the address-of can be optimized away. | |
5148 | ||
5149 | The vectors are implemented using the trailing array idiom, thus they | |
5150 | are not resizeable without changing the address of the vector object | |
5151 | itself. This means you cannot have variables or fields of vector type | |
5152 | --- always use a pointer to a vector. The one exception is the final | |
5153 | field of a structure, which could be a vector type. You will have to | |
5154 | use the @code{embedded_size} & @code{embedded_init} calls to create | |
5155 | such objects, and they will probably not be resizeable (so don't use | |
5156 | the @dfn{safe} allocation variants). The trailing array idiom is used | |
5157 | (rather than a pointer to an array of data), because, if we allow | |
5158 | @code{NULL} to also represent an empty vector, empty vectors occupy | |
5159 | minimal space in the structure containing them. | |
5160 | ||
5161 | Each operation that increases the number of active elements is | |
5162 | available in @dfn{quick} and @dfn{safe} variants. The former presumes | |
5163 | that there is sufficient allocated space for the operation to succeed | |
5164 | (it dies if there is not). The latter will reallocate the vector, if | |
5165 | needed. Reallocation causes an exponential increase in vector size. | |
5166 | If you know you will be adding N elements, it would be more efficient | |
5167 | to use the reserve operation before adding the elements with the | |
5168 | @dfn{quick} operation. This will ensure there are at least as many | |
5169 | elements as you ask for, it will exponentially increase if there are | |
5170 | too few spare slots. If you want reserve a specific number of slots, | |
5171 | but do not want the exponential increase (for instance, you know this | |
5172 | is the last allocation), use a negative number for reservation. You | |
5173 | can also create a vector of a specific size from the get go. | |
5174 | ||
5175 | You should prefer the push and pop operations, as they append and | |
5176 | remove from the end of the vector. If you need to remove several items | |
5177 | in one go, use the truncate operation. The insert and remove | |
5178 | operations allow you to change elements in the middle of the vector. | |
5179 | There are two remove operations, one which preserves the element | |
5180 | ordering @code{ordered_remove}, and one which does not | |
5181 | @code{unordered_remove}. The latter function copies the end element | |
5182 | into the removed slot, rather than invoke a memmove operation. The | |
5183 | @code{lower_bound} function will determine where to place an item in | |
5184 | the array using insert that will maintain sorted order. | |
5185 | ||
5186 | If you need to directly manipulate a vector, then the @code{address} | |
5187 | accessor will return the address of the start of the vector. Also the | |
5188 | @code{space} predicate will tell you whether there is spare capacity in the | |
5189 | vector. You will not normally need to use these two functions. | |
5190 | ||
5191 | Vector types are defined using a | |
5192 | @code{DEF_VEC_@{O,P,I@}(@var{typename})} macro. Variables of vector | |
5193 | type are declared using a @code{VEC(@var{typename})} macro. The | |
5194 | characters @code{O}, @code{P} and @code{I} indicate whether | |
5195 | @var{typename} is an object (@code{O}), pointer (@code{P}) or integral | |
5196 | (@code{I}) type. Be careful to pick the correct one, as you'll get an | |
5197 | awkward and inefficient API if you use the wrong one. There is a | |
5198 | check, which results in a compile-time warning, for the @code{P} and | |
5199 | @code{I} versions, but there is no check for the @code{O} versions, as | |
5200 | that is not possible in plain C. | |
5201 | ||
5202 | An example of their use would be, | |
5203 | ||
5204 | @smallexample | |
5205 | DEF_VEC_P(tree); // non-managed tree vector. | |
5206 | ||
5207 | struct my_struct @{ | |
5208 | VEC(tree) *v; // A (pointer to) a vector of tree pointers. | |
5209 | @}; | |
5210 | ||
5211 | struct my_struct *s; | |
5212 | ||
5213 | if (VEC_length(tree, s->v)) @{ we have some contents @} | |
5214 | VEC_safe_push(tree, s->v, decl); // append some decl onto the end | |
5215 | for (ix = 0; VEC_iterate(tree, s->v, ix, elt); ix++) | |
5216 | @{ do something with elt @} | |
5217 | ||
5218 | @end smallexample | |
5219 | ||
5220 | The @file{vec.h} file provides details on how to invoke the various | |
5221 | accessors provided. They are enumerated here: | |
5222 | ||
5223 | @table @code | |
5224 | @item VEC_length | |
5225 | Return the number of items in the array, | |
5226 | ||
5227 | @item VEC_empty | |
5228 | Return true if the array has no elements. | |
5229 | ||
5230 | @item VEC_last | |
5231 | @itemx VEC_index | |
5232 | Return the last or arbitrary item in the array. | |
5233 | ||
5234 | @item VEC_iterate | |
5235 | Access an array element and indicate whether the array has been | |
5236 | traversed. | |
5237 | ||
5238 | @item VEC_alloc | |
5239 | @itemx VEC_free | |
5240 | Create and destroy an array. | |
5241 | ||
5242 | @item VEC_embedded_size | |
5243 | @itemx VEC_embedded_init | |
5244 | Helpers for embedding an array as the final element of another struct. | |
5245 | ||
5246 | @item VEC_copy | |
5247 | Duplicate an array. | |
5248 | ||
5249 | @item VEC_space | |
5250 | Return the amount of free space in an array. | |
5251 | ||
5252 | @item VEC_reserve | |
5253 | Ensure a certain amount of free space. | |
5254 | ||
5255 | @item VEC_quick_push | |
5256 | @itemx VEC_safe_push | |
5257 | Append to an array, either assuming the space is available, or making | |
5258 | sure that it is. | |
5259 | ||
5260 | @item VEC_pop | |
5261 | Remove the last item from an array. | |
5262 | ||
5263 | @item VEC_truncate | |
5264 | Remove several items from the end of an array. | |
5265 | ||
5266 | @item VEC_safe_grow | |
5267 | Add several items to the end of an array. | |
5268 | ||
5269 | @item VEC_replace | |
5270 | Overwrite an item in the array. | |
5271 | ||
5272 | @item VEC_quick_insert | |
5273 | @itemx VEC_safe_insert | |
5274 | Insert an item into the middle of the array. Either the space must | |
5275 | already exist, or the space is created. | |
5276 | ||
5277 | @item VEC_ordered_remove | |
5278 | @itemx VEC_unordered_remove | |
5279 | Remove an item from the array, preserving order or not. | |
5280 | ||
5281 | @item VEC_block_remove | |
5282 | Remove a set of items from the array. | |
5283 | ||
5284 | @item VEC_address | |
5285 | Provide the address of the first element. | |
5286 | ||
5287 | @item VEC_lower_bound | |
5288 | Binary search the array. | |
5289 | ||
5290 | @end table | |
5291 | ||
c906108c SS |
5292 | @section include |
5293 | ||
5294 | @node Coding | |
5295 | ||
5296 | @chapter Coding | |
5297 | ||
5298 | This chapter covers topics that are lower-level than the major | |
25822942 | 5299 | algorithms of @value{GDBN}. |
c906108c SS |
5300 | |
5301 | @section Cleanups | |
56caf160 | 5302 | @cindex cleanups |
c906108c SS |
5303 | |
5304 | Cleanups are a structured way to deal with things that need to be done | |
cc1cb004 | 5305 | later. |
c906108c | 5306 | |
cc1cb004 AC |
5307 | When your code does something (e.g., @code{xmalloc} some memory, or |
5308 | @code{open} a file) that needs to be undone later (e.g., @code{xfree} | |
5309 | the memory or @code{close} the file), it can make a cleanup. The | |
5310 | cleanup will be done at some future point: when the command is finished | |
5311 | and control returns to the top level; when an error occurs and the stack | |
5312 | is unwound; or when your code decides it's time to explicitly perform | |
5313 | cleanups. Alternatively you can elect to discard the cleanups you | |
5314 | created. | |
c906108c SS |
5315 | |
5316 | Syntax: | |
5317 | ||
5318 | @table @code | |
c906108c SS |
5319 | @item struct cleanup *@var{old_chain}; |
5320 | Declare a variable which will hold a cleanup chain handle. | |
5321 | ||
56caf160 | 5322 | @findex make_cleanup |
c906108c SS |
5323 | @item @var{old_chain} = make_cleanup (@var{function}, @var{arg}); |
5324 | Make a cleanup which will cause @var{function} to be called with | |
5325 | @var{arg} (a @code{char *}) later. The result, @var{old_chain}, is a | |
cc1cb004 AC |
5326 | handle that can later be passed to @code{do_cleanups} or |
5327 | @code{discard_cleanups}. Unless you are going to call | |
5328 | @code{do_cleanups} or @code{discard_cleanups}, you can ignore the result | |
5329 | from @code{make_cleanup}. | |
c906108c | 5330 | |
56caf160 | 5331 | @findex do_cleanups |
c906108c | 5332 | @item do_cleanups (@var{old_chain}); |
cc1cb004 AC |
5333 | Do all cleanups added to the chain since the corresponding |
5334 | @code{make_cleanup} call was made. | |
5335 | ||
5336 | @findex discard_cleanups | |
5337 | @item discard_cleanups (@var{old_chain}); | |
5338 | Same as @code{do_cleanups} except that it just removes the cleanups from | |
5339 | the chain and does not call the specified functions. | |
5340 | @end table | |
5341 | ||
5342 | Cleanups are implemented as a chain. The handle returned by | |
5343 | @code{make_cleanups} includes the cleanup passed to the call and any | |
5344 | later cleanups appended to the chain (but not yet discarded or | |
5345 | performed). E.g.: | |
56caf160 | 5346 | |
474c8240 | 5347 | @smallexample |
c906108c | 5348 | make_cleanup (a, 0); |
cc1cb004 AC |
5349 | @{ |
5350 | struct cleanup *old = make_cleanup (b, 0); | |
5351 | make_cleanup (c, 0) | |
5352 | ... | |
5353 | do_cleanups (old); | |
5354 | @} | |
474c8240 | 5355 | @end smallexample |
56caf160 | 5356 | |
c906108c | 5357 | @noindent |
cc1cb004 AC |
5358 | will call @code{c()} and @code{b()} but will not call @code{a()}. The |
5359 | cleanup that calls @code{a()} will remain in the cleanup chain, and will | |
5360 | be done later unless otherwise discarded.@refill | |
5361 | ||
5362 | Your function should explicitly do or discard the cleanups it creates. | |
5363 | Failing to do this leads to non-deterministic behavior since the caller | |
5364 | will arbitrarily do or discard your functions cleanups. This need leads | |
5365 | to two common cleanup styles. | |
5366 | ||
5367 | The first style is try/finally. Before it exits, your code-block calls | |
5368 | @code{do_cleanups} with the old cleanup chain and thus ensures that your | |
5369 | code-block's cleanups are always performed. For instance, the following | |
5370 | code-segment avoids a memory leak problem (even when @code{error} is | |
5371 | called and a forced stack unwind occurs) by ensuring that the | |
5372 | @code{xfree} will always be called: | |
c906108c | 5373 | |
474c8240 | 5374 | @smallexample |
cc1cb004 AC |
5375 | struct cleanup *old = make_cleanup (null_cleanup, 0); |
5376 | data = xmalloc (sizeof blah); | |
5377 | make_cleanup (xfree, data); | |
5378 | ... blah blah ... | |
5379 | do_cleanups (old); | |
474c8240 | 5380 | @end smallexample |
cc1cb004 AC |
5381 | |
5382 | The second style is try/except. Before it exits, your code-block calls | |
5383 | @code{discard_cleanups} with the old cleanup chain and thus ensures that | |
5384 | any created cleanups are not performed. For instance, the following | |
5385 | code segment, ensures that the file will be closed but only if there is | |
5386 | an error: | |
5387 | ||
474c8240 | 5388 | @smallexample |
cc1cb004 AC |
5389 | FILE *file = fopen ("afile", "r"); |
5390 | struct cleanup *old = make_cleanup (close_file, file); | |
5391 | ... blah blah ... | |
5392 | discard_cleanups (old); | |
5393 | return file; | |
474c8240 | 5394 | @end smallexample |
c906108c | 5395 | |
c1468174 | 5396 | Some functions, e.g., @code{fputs_filtered()} or @code{error()}, specify |
c906108c SS |
5397 | that they ``should not be called when cleanups are not in place''. This |
5398 | means that any actions you need to reverse in the case of an error or | |
5399 | interruption must be on the cleanup chain before you call these | |
5400 | functions, since they might never return to your code (they | |
5401 | @samp{longjmp} instead). | |
5402 | ||
ba8c9337 AC |
5403 | @section Per-architecture module data |
5404 | @cindex per-architecture module data | |
5405 | @cindex multi-arch data | |
5406 | @cindex data-pointer, per-architecture/per-module | |
5407 | ||
fc989b7a AC |
5408 | The multi-arch framework includes a mechanism for adding module |
5409 | specific per-architecture data-pointers to the @code{struct gdbarch} | |
5410 | architecture object. | |
5411 | ||
5412 | A module registers one or more per-architecture data-pointers using: | |
5413 | ||
5414 | @deftypefun struct gdbarch_data *gdbarch_data_register_pre_init (gdbarch_data_pre_init_ftype *@var{pre_init}) | |
5415 | @var{pre_init} is used to, on-demand, allocate an initial value for a | |
5416 | per-architecture data-pointer using the architecture's obstack (passed | |
5417 | in as a parameter). Since @var{pre_init} can be called during | |
5418 | architecture creation, it is not parameterized with the architecture. | |
5419 | and must not call modules that use per-architecture data. | |
5420 | @end deftypefun | |
ba8c9337 | 5421 | |
fc989b7a AC |
5422 | @deftypefun struct gdbarch_data *gdbarch_data_register_post_init (gdbarch_data_post_init_ftype *@var{post_init}) |
5423 | @var{post_init} is used to obtain an initial value for a | |
5424 | per-architecture data-pointer @emph{after}. Since @var{post_init} is | |
5425 | always called after architecture creation, it both receives the fully | |
5426 | initialized architecture and is free to call modules that use | |
5427 | per-architecture data (care needs to be taken to ensure that those | |
5428 | other modules do not try to call back to this module as that will | |
5429 | create in cycles in the initialization call graph). | |
5430 | @end deftypefun | |
ba8c9337 | 5431 | |
fc989b7a AC |
5432 | These functions return a @code{struct gdbarch_data} that is used to |
5433 | identify the per-architecture data-pointer added for that module. | |
ba8c9337 | 5434 | |
fc989b7a | 5435 | The per-architecture data-pointer is accessed using the function: |
ba8c9337 | 5436 | |
fc989b7a AC |
5437 | @deftypefun void *gdbarch_data (struct gdbarch *@var{gdbarch}, struct gdbarch_data *@var{data_handle}) |
5438 | Given the architecture @var{arch} and module data handle | |
5439 | @var{data_handle} (returned by @code{gdbarch_data_register_pre_init} | |
5440 | or @code{gdbarch_data_register_post_init}), this function returns the | |
5441 | current value of the per-architecture data-pointer. If the data | |
5442 | pointer is @code{NULL}, it is first initialized by calling the | |
5443 | corresponding @var{pre_init} or @var{post_init} method. | |
ba8c9337 AC |
5444 | @end deftypefun |
5445 | ||
fc989b7a | 5446 | The examples below assume the following definitions: |
ba8c9337 AC |
5447 | |
5448 | @smallexample | |
e7f16015 | 5449 | struct nozel @{ int total; @}; |
ba8c9337 | 5450 | static struct gdbarch_data *nozel_handle; |
ba8c9337 AC |
5451 | @end smallexample |
5452 | ||
fc989b7a AC |
5453 | A module can extend the architecture vector, adding additional |
5454 | per-architecture data, using the @var{pre_init} method. The module's | |
5455 | per-architecture data is then initialized during architecture | |
5456 | creation. | |
ba8c9337 | 5457 | |
fc989b7a AC |
5458 | In the below, the module's per-architecture @emph{nozel} is added. An |
5459 | architecture can specify its nozel by calling @code{set_gdbarch_nozel} | |
5460 | from @code{gdbarch_init}. | |
ba8c9337 AC |
5461 | |
5462 | @smallexample | |
fc989b7a AC |
5463 | static void * |
5464 | nozel_pre_init (struct obstack *obstack) | |
ba8c9337 | 5465 | @{ |
fc989b7a AC |
5466 | struct nozel *data = OBSTACK_ZALLOC (obstack, struct nozel); |
5467 | return data; | |
5468 | @} | |
ba8c9337 AC |
5469 | @end smallexample |
5470 | ||
ba8c9337 | 5471 | @smallexample |
fc989b7a AC |
5472 | extern void |
5473 | set_gdbarch_nozel (struct gdbarch *gdbarch, int total) | |
ba8c9337 | 5474 | @{ |
ba8c9337 | 5475 | struct nozel *data = gdbarch_data (gdbarch, nozel_handle); |
fc989b7a | 5476 | data->total = nozel; |
ba8c9337 AC |
5477 | @} |
5478 | @end smallexample | |
5479 | ||
fc989b7a AC |
5480 | A module can on-demand create architecture dependant data structures |
5481 | using @code{post_init}. | |
ba8c9337 | 5482 | |
fc989b7a AC |
5483 | In the below, the nozel's total is computed on-demand by |
5484 | @code{nozel_post_init} using information obtained from the | |
5485 | architecture. | |
ba8c9337 AC |
5486 | |
5487 | @smallexample | |
fc989b7a AC |
5488 | static void * |
5489 | nozel_post_init (struct gdbarch *gdbarch) | |
ba8c9337 | 5490 | @{ |
fc989b7a AC |
5491 | struct nozel *data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct nozel); |
5492 | nozel->total = gdbarch@dots{} (gdbarch); | |
5493 | return data; | |
ba8c9337 AC |
5494 | @} |
5495 | @end smallexample | |
5496 | ||
5497 | @smallexample | |
fc989b7a AC |
5498 | extern int |
5499 | nozel_total (struct gdbarch *gdbarch) | |
ba8c9337 | 5500 | @{ |
fc989b7a AC |
5501 | struct nozel *data = gdbarch_data (gdbarch, nozel_handle); |
5502 | return data->total; | |
ba8c9337 AC |
5503 | @} |
5504 | @end smallexample | |
5505 | ||
c906108c | 5506 | @section Wrapping Output Lines |
56caf160 | 5507 | @cindex line wrap in output |
c906108c | 5508 | |
56caf160 | 5509 | @findex wrap_here |
c906108c SS |
5510 | Output that goes through @code{printf_filtered} or @code{fputs_filtered} |
5511 | or @code{fputs_demangled} needs only to have calls to @code{wrap_here} | |
5512 | added in places that would be good breaking points. The utility | |
5513 | routines will take care of actually wrapping if the line width is | |
5514 | exceeded. | |
5515 | ||
5516 | The argument to @code{wrap_here} is an indentation string which is | |
5517 | printed @emph{only} if the line breaks there. This argument is saved | |
5518 | away and used later. It must remain valid until the next call to | |
5519 | @code{wrap_here} or until a newline has been printed through the | |
5520 | @code{*_filtered} functions. Don't pass in a local variable and then | |
5521 | return! | |
5522 | ||
56caf160 | 5523 | It is usually best to call @code{wrap_here} after printing a comma or |
c906108c SS |
5524 | space. If you call it before printing a space, make sure that your |
5525 | indentation properly accounts for the leading space that will print if | |
5526 | the line wraps there. | |
5527 | ||
5528 | Any function or set of functions that produce filtered output must | |
5529 | finish by printing a newline, to flush the wrap buffer, before switching | |
56caf160 | 5530 | to unfiltered (@code{printf}) output. Symbol reading routines that |
c906108c SS |
5531 | print warnings are a good example. |
5532 | ||
25822942 | 5533 | @section @value{GDBN} Coding Standards |
56caf160 | 5534 | @cindex coding standards |
c906108c | 5535 | |
25822942 | 5536 | @value{GDBN} follows the GNU coding standards, as described in |
c906108c | 5537 | @file{etc/standards.texi}. This file is also available for anonymous |
af6c57ea AC |
5538 | FTP from GNU archive sites. @value{GDBN} takes a strict interpretation |
5539 | of the standard; in general, when the GNU standard recommends a practice | |
5540 | but does not require it, @value{GDBN} requires it. | |
c906108c | 5541 | |
56caf160 EZ |
5542 | @value{GDBN} follows an additional set of coding standards specific to |
5543 | @value{GDBN}, as described in the following sections. | |
c906108c | 5544 | |
af6c57ea | 5545 | |
b9aa90c9 | 5546 | @subsection ISO C |
af6c57ea | 5547 | |
b9aa90c9 AC |
5548 | @value{GDBN} assumes an ISO/IEC 9899:1990 (a.k.a.@: ISO C90) compliant |
5549 | compiler. | |
af6c57ea | 5550 | |
b9aa90c9 | 5551 | @value{GDBN} does not assume an ISO C or POSIX compliant C library. |
af6c57ea AC |
5552 | |
5553 | ||
5554 | @subsection Memory Management | |
5555 | ||
5556 | @value{GDBN} does not use the functions @code{malloc}, @code{realloc}, | |
5557 | @code{calloc}, @code{free} and @code{asprintf}. | |
5558 | ||
5559 | @value{GDBN} uses the functions @code{xmalloc}, @code{xrealloc} and | |
5560 | @code{xcalloc} when allocating memory. Unlike @code{malloc} et.al.@: | |
5561 | these functions do not return when the memory pool is empty. Instead, | |
5562 | they unwind the stack using cleanups. These functions return | |
5563 | @code{NULL} when requested to allocate a chunk of memory of size zero. | |
5564 | ||
5565 | @emph{Pragmatics: By using these functions, the need to check every | |
5566 | memory allocation is removed. These functions provide portable | |
5567 | behavior.} | |
5568 | ||
5569 | @value{GDBN} does not use the function @code{free}. | |
5570 | ||
5571 | @value{GDBN} uses the function @code{xfree} to return memory to the | |
5572 | memory pool. Consistent with ISO-C, this function ignores a request to | |
5573 | free a @code{NULL} pointer. | |
5574 | ||
5575 | @emph{Pragmatics: On some systems @code{free} fails when passed a | |
5576 | @code{NULL} pointer.} | |
5577 | ||
5578 | @value{GDBN} can use the non-portable function @code{alloca} for the | |
5579 | allocation of small temporary values (such as strings). | |
5580 | ||
5581 | @emph{Pragmatics: This function is very non-portable. Some systems | |
5582 | restrict the memory being allocated to no more than a few kilobytes.} | |
5583 | ||
5584 | @value{GDBN} uses the string function @code{xstrdup} and the print | |
b435e160 | 5585 | function @code{xstrprintf}. |
af6c57ea AC |
5586 | |
5587 | @emph{Pragmatics: @code{asprintf} and @code{strdup} can fail. Print | |
5588 | functions such as @code{sprintf} are very prone to buffer overflow | |
5589 | errors.} | |
5590 | ||
5591 | ||
5592 | @subsection Compiler Warnings | |
56caf160 | 5593 | @cindex compiler warnings |
af6c57ea | 5594 | |
aa79a185 DJ |
5595 | With few exceptions, developers should avoid the configuration option |
5596 | @samp{--disable-werror} when building @value{GDBN}. The exceptions | |
5597 | are listed in the file @file{gdb/MAINTAINERS}. The default, when | |
5598 | building with @sc{gcc}, is @samp{--enable-werror}. | |
af6c57ea AC |
5599 | |
5600 | This option causes @value{GDBN} (when built using GCC) to be compiled | |
5601 | with a carefully selected list of compiler warning flags. Any warnings | |
aa79a185 | 5602 | from those flags are treated as errors. |
af6c57ea AC |
5603 | |
5604 | The current list of warning flags includes: | |
5605 | ||
5606 | @table @samp | |
aa79a185 DJ |
5607 | @item -Wall |
5608 | Recommended @sc{gcc} warnings. | |
af6c57ea | 5609 | |
aa79a185 | 5610 | @item -Wdeclaration-after-statement |
af6c57ea | 5611 | |
aa79a185 DJ |
5612 | @sc{gcc} 3.x (and later) and @sc{c99} allow declarations mixed with |
5613 | code, but @sc{gcc} 2.x and @sc{c89} do not. | |
af6c57ea | 5614 | |
aa79a185 | 5615 | @item -Wpointer-arith |
af6c57ea | 5616 | |
aa79a185 DJ |
5617 | @item -Wformat-nonliteral |
5618 | Non-literal format strings, with a few exceptions, are bugs - they | |
d3e8051b | 5619 | might contain unintended user-supplied format specifiers. |
af6c57ea | 5620 | Since @value{GDBN} uses the @code{format printf} attribute on all |
aa79a185 | 5621 | @code{printf} like functions this checks not just @code{printf} calls |
af6c57ea AC |
5622 | but also calls to functions such as @code{fprintf_unfiltered}. |
5623 | ||
7be93b9e JB |
5624 | @item -Wno-pointer-sign |
5625 | In version 4.0, GCC began warning about pointer argument passing or | |
5626 | assignment even when the source and destination differed only in | |
5627 | signedness. However, most @value{GDBN} code doesn't distinguish | |
5628 | carefully between @code{char} and @code{unsigned char}. In early 2006 | |
5629 | the @value{GDBN} developers decided correcting these warnings wasn't | |
5630 | worth the time it would take. | |
5631 | ||
aa79a185 DJ |
5632 | @item -Wno-unused-parameter |
5633 | Due to the way that @value{GDBN} is implemented many functions have | |
5634 | unused parameters. Consequently this warning is avoided. The macro | |
af6c57ea AC |
5635 | @code{ATTRIBUTE_UNUSED} is not used as it leads to false negatives --- |
5636 | it is not an error to have @code{ATTRIBUTE_UNUSED} on a parameter that | |
aa79a185 DJ |
5637 | is being used. |
5638 | ||
5639 | @item -Wno-unused | |
5640 | @itemx -Wno-switch | |
58b38ee2 | 5641 | @itemx -Wno-char-subscripts |
aa79a185 DJ |
5642 | These are warnings which might be useful for @value{GDBN}, but are |
5643 | currently too noisy to enable with @samp{-Werror}. | |
af6c57ea | 5644 | |
aa79a185 | 5645 | @end table |
c906108c SS |
5646 | |
5647 | @subsection Formatting | |
5648 | ||
56caf160 | 5649 | @cindex source code formatting |
c906108c SS |
5650 | The standard GNU recommendations for formatting must be followed |
5651 | strictly. | |
5652 | ||
af6c57ea AC |
5653 | A function declaration should not have its name in column zero. A |
5654 | function definition should have its name in column zero. | |
5655 | ||
474c8240 | 5656 | @smallexample |
af6c57ea AC |
5657 | /* Declaration */ |
5658 | static void foo (void); | |
5659 | /* Definition */ | |
5660 | void | |
5661 | foo (void) | |
5662 | @{ | |
5663 | @} | |
474c8240 | 5664 | @end smallexample |
af6c57ea AC |
5665 | |
5666 | @emph{Pragmatics: This simplifies scripting. Function definitions can | |
5667 | be found using @samp{^function-name}.} | |
c906108c | 5668 | |
af6c57ea AC |
5669 | There must be a space between a function or macro name and the opening |
5670 | parenthesis of its argument list (except for macro definitions, as | |
5671 | required by C). There must not be a space after an open paren/bracket | |
5672 | or before a close paren/bracket. | |
c906108c SS |
5673 | |
5674 | While additional whitespace is generally helpful for reading, do not use | |
5675 | more than one blank line to separate blocks, and avoid adding whitespace | |
af6c57ea AC |
5676 | after the end of a program line (as of 1/99, some 600 lines had |
5677 | whitespace after the semicolon). Excess whitespace causes difficulties | |
5678 | for @code{diff} and @code{patch} utilities. | |
5679 | ||
5680 | Pointers are declared using the traditional K&R C style: | |
5681 | ||
474c8240 | 5682 | @smallexample |
af6c57ea | 5683 | void *foo; |
474c8240 | 5684 | @end smallexample |
af6c57ea AC |
5685 | |
5686 | @noindent | |
5687 | and not: | |
5688 | ||
474c8240 | 5689 | @smallexample |
af6c57ea AC |
5690 | void * foo; |
5691 | void* foo; | |
474c8240 | 5692 | @end smallexample |
c906108c SS |
5693 | |
5694 | @subsection Comments | |
5695 | ||
56caf160 | 5696 | @cindex comment formatting |
c906108c SS |
5697 | The standard GNU requirements on comments must be followed strictly. |
5698 | ||
af6c57ea AC |
5699 | Block comments must appear in the following form, with no @code{/*}- or |
5700 | @code{*/}-only lines, and no leading @code{*}: | |
c906108c | 5701 | |
474c8240 | 5702 | @smallexample |
c906108c SS |
5703 | /* Wait for control to return from inferior to debugger. If inferior |
5704 | gets a signal, we may decide to start it up again instead of | |
5705 | returning. That is why there is a loop in this function. When | |
5706 | this function actually returns it means the inferior should be left | |
25822942 | 5707 | stopped and @value{GDBN} should read more commands. */ |
474c8240 | 5708 | @end smallexample |
c906108c SS |
5709 | |
5710 | (Note that this format is encouraged by Emacs; tabbing for a multi-line | |
56caf160 | 5711 | comment works correctly, and @kbd{M-q} fills the block consistently.) |
c906108c SS |
5712 | |
5713 | Put a blank line between the block comments preceding function or | |
5714 | variable definitions, and the definition itself. | |
5715 | ||
5716 | In general, put function-body comments on lines by themselves, rather | |
5717 | than trying to fit them into the 20 characters left at the end of a | |
5718 | line, since either the comment or the code will inevitably get longer | |
5719 | than will fit, and then somebody will have to move it anyhow. | |
5720 | ||
5721 | @subsection C Usage | |
5722 | ||
56caf160 | 5723 | @cindex C data types |
c906108c SS |
5724 | Code must not depend on the sizes of C data types, the format of the |
5725 | host's floating point numbers, the alignment of anything, or the order | |
5726 | of evaluation of expressions. | |
5727 | ||
56caf160 | 5728 | @cindex function usage |
c906108c | 5729 | Use functions freely. There are only a handful of compute-bound areas |
56caf160 EZ |
5730 | in @value{GDBN} that might be affected by the overhead of a function |
5731 | call, mainly in symbol reading. Most of @value{GDBN}'s performance is | |
5732 | limited by the target interface (whether serial line or system call). | |
c906108c SS |
5733 | |
5734 | However, use functions with moderation. A thousand one-line functions | |
5735 | are just as hard to understand as a single thousand-line function. | |
5736 | ||
af6c57ea | 5737 | @emph{Macros are bad, M'kay.} |
9e678452 CF |
5738 | (But if you have to use a macro, make sure that the macro arguments are |
5739 | protected with parentheses.) | |
af6c57ea AC |
5740 | |
5741 | @cindex types | |
c906108c | 5742 | |
af6c57ea AC |
5743 | Declarations like @samp{struct foo *} should be used in preference to |
5744 | declarations like @samp{typedef struct foo @{ @dots{} @} *foo_ptr}. | |
5745 | ||
5746 | ||
5747 | @subsection Function Prototypes | |
56caf160 | 5748 | @cindex function prototypes |
af6c57ea AC |
5749 | |
5750 | Prototypes must be used when both @emph{declaring} and @emph{defining} | |
5751 | a function. Prototypes for @value{GDBN} functions must include both the | |
5752 | argument type and name, with the name matching that used in the actual | |
5753 | function definition. | |
c906108c | 5754 | |
53a5351d JM |
5755 | All external functions should have a declaration in a header file that |
5756 | callers include, except for @code{_initialize_*} functions, which must | |
5757 | be external so that @file{init.c} construction works, but shouldn't be | |
5758 | visible to random source files. | |
c906108c | 5759 | |
af6c57ea AC |
5760 | Where a source file needs a forward declaration of a static function, |
5761 | that declaration must appear in a block near the top of the source file. | |
5762 | ||
5763 | ||
5764 | @subsection Internal Error Recovery | |
5765 | ||
5766 | During its execution, @value{GDBN} can encounter two types of errors. | |
5767 | User errors and internal errors. User errors include not only a user | |
5768 | entering an incorrect command but also problems arising from corrupt | |
5769 | object files and system errors when interacting with the target. | |
937f164b FF |
5770 | Internal errors include situations where @value{GDBN} has detected, at |
5771 | run time, a corrupt or erroneous situation. | |
af6c57ea AC |
5772 | |
5773 | When reporting an internal error, @value{GDBN} uses | |
5774 | @code{internal_error} and @code{gdb_assert}. | |
5775 | ||
5776 | @value{GDBN} must not call @code{abort} or @code{assert}. | |
5777 | ||
5778 | @emph{Pragmatics: There is no @code{internal_warning} function. Either | |
5779 | the code detected a user error, recovered from it and issued a | |
5780 | @code{warning} or the code failed to correctly recover from the user | |
5781 | error and issued an @code{internal_error}.} | |
5782 | ||
5783 | @subsection File Names | |
5784 | ||
5785 | Any file used when building the core of @value{GDBN} must be in lower | |
5786 | case. Any file used when building the core of @value{GDBN} must be 8.3 | |
5787 | unique. These requirements apply to both source and generated files. | |
5788 | ||
5789 | @emph{Pragmatics: The core of @value{GDBN} must be buildable on many | |
5790 | platforms including DJGPP and MacOS/HFS. Every time an unfriendly file | |
5791 | is introduced to the build process both @file{Makefile.in} and | |
5792 | @file{configure.in} need to be modified accordingly. Compare the | |
5793 | convoluted conversion process needed to transform @file{COPYING} into | |
5794 | @file{copying.c} with the conversion needed to transform | |
5795 | @file{version.in} into @file{version.c}.} | |
5796 | ||
5797 | Any file non 8.3 compliant file (that is not used when building the core | |
5798 | of @value{GDBN}) must be added to @file{gdb/config/djgpp/fnchange.lst}. | |
5799 | ||
5800 | @emph{Pragmatics: This is clearly a compromise.} | |
5801 | ||
5802 | When @value{GDBN} has a local version of a system header file (ex | |
5803 | @file{string.h}) the file name based on the POSIX header prefixed with | |
b4177fca DJ |
5804 | @file{gdb_} (@file{gdb_string.h}). These headers should be relatively |
5805 | independent: they should use only macros defined by @file{configure}, | |
5806 | the compiler, or the host; they should include only system headers; they | |
5807 | should refer only to system types. They may be shared between multiple | |
5808 | programs, e.g.@: @value{GDBN} and @sc{gdbserver}. | |
af6c57ea AC |
5809 | |
5810 | For other files @samp{-} is used as the separator. | |
5811 | ||
5812 | ||
5813 | @subsection Include Files | |
5814 | ||
e2b28d04 | 5815 | A @file{.c} file should include @file{defs.h} first. |
af6c57ea | 5816 | |
e2b28d04 AC |
5817 | A @file{.c} file should directly include the @code{.h} file of every |
5818 | declaration and/or definition it directly refers to. It cannot rely on | |
5819 | indirect inclusion. | |
af6c57ea | 5820 | |
e2b28d04 AC |
5821 | A @file{.h} file should directly include the @code{.h} file of every |
5822 | declaration and/or definition it directly refers to. It cannot rely on | |
5823 | indirect inclusion. Exception: The file @file{defs.h} does not need to | |
5824 | be directly included. | |
af6c57ea | 5825 | |
e2b28d04 | 5826 | An external declaration should only appear in one include file. |
af6c57ea | 5827 | |
e2b28d04 AC |
5828 | An external declaration should never appear in a @code{.c} file. |
5829 | Exception: a declaration for the @code{_initialize} function that | |
5830 | pacifies @option{-Wmissing-declaration}. | |
5831 | ||
5832 | A @code{typedef} definition should only appear in one include file. | |
5833 | ||
5834 | An opaque @code{struct} declaration can appear in multiple @file{.h} | |
5835 | files. Where possible, a @file{.h} file should use an opaque | |
5836 | @code{struct} declaration instead of an include. | |
5837 | ||
5838 | All @file{.h} files should be wrapped in: | |
af6c57ea | 5839 | |
474c8240 | 5840 | @smallexample |
af6c57ea AC |
5841 | #ifndef INCLUDE_FILE_NAME_H |
5842 | #define INCLUDE_FILE_NAME_H | |
5843 | header body | |
5844 | #endif | |
474c8240 | 5845 | @end smallexample |
af6c57ea | 5846 | |
c906108c | 5847 | |
dab11f21 | 5848 | @subsection Clean Design and Portable Implementation |
c906108c | 5849 | |
56caf160 | 5850 | @cindex design |
c906108c | 5851 | In addition to getting the syntax right, there's the little question of |
25822942 | 5852 | semantics. Some things are done in certain ways in @value{GDBN} because long |
c906108c SS |
5853 | experience has shown that the more obvious ways caused various kinds of |
5854 | trouble. | |
5855 | ||
56caf160 | 5856 | @cindex assumptions about targets |
c906108c SS |
5857 | You can't assume the byte order of anything that comes from a target |
5858 | (including @var{value}s, object files, and instructions). Such things | |
56caf160 EZ |
5859 | must be byte-swapped using @code{SWAP_TARGET_AND_HOST} in |
5860 | @value{GDBN}, or one of the swap routines defined in @file{bfd.h}, | |
5861 | such as @code{bfd_get_32}. | |
c906108c SS |
5862 | |
5863 | You can't assume that you know what interface is being used to talk to | |
5864 | the target system. All references to the target must go through the | |
5865 | current @code{target_ops} vector. | |
5866 | ||
5867 | You can't assume that the host and target machines are the same machine | |
5868 | (except in the ``native'' support modules). In particular, you can't | |
5869 | assume that the target machine's header files will be available on the | |
5870 | host machine. Target code must bring along its own header files -- | |
5871 | written from scratch or explicitly donated by their owner, to avoid | |
5872 | copyright problems. | |
5873 | ||
56caf160 | 5874 | @cindex portability |
c906108c SS |
5875 | Insertion of new @code{#ifdef}'s will be frowned upon. It's much better |
5876 | to write the code portably than to conditionalize it for various | |
5877 | systems. | |
5878 | ||
56caf160 | 5879 | @cindex system dependencies |
c906108c SS |
5880 | New @code{#ifdef}'s which test for specific compilers or manufacturers |
5881 | or operating systems are unacceptable. All @code{#ifdef}'s should test | |
5882 | for features. The information about which configurations contain which | |
5883 | features should be segregated into the configuration files. Experience | |
5884 | has proven far too often that a feature unique to one particular system | |
5885 | often creeps into other systems; and that a conditional based on some | |
5886 | predefined macro for your current system will become worthless over | |
5887 | time, as new versions of your system come out that behave differently | |
5888 | with regard to this feature. | |
5889 | ||
5890 | Adding code that handles specific architectures, operating systems, | |
af6c57ea | 5891 | target interfaces, or hosts, is not acceptable in generic code. |
c906108c | 5892 | |
dab11f21 EZ |
5893 | @cindex portable file name handling |
5894 | @cindex file names, portability | |
5895 | One particularly notorious area where system dependencies tend to | |
5896 | creep in is handling of file names. The mainline @value{GDBN} code | |
5897 | assumes Posix semantics of file names: absolute file names begin with | |
5898 | a forward slash @file{/}, slashes are used to separate leading | |
5899 | directories, case-sensitive file names. These assumptions are not | |
5900 | necessarily true on non-Posix systems such as MS-Windows. To avoid | |
5901 | system-dependent code where you need to take apart or construct a file | |
5902 | name, use the following portable macros: | |
5903 | ||
5904 | @table @code | |
5905 | @findex HAVE_DOS_BASED_FILE_SYSTEM | |
5906 | @item HAVE_DOS_BASED_FILE_SYSTEM | |
5907 | This preprocessing symbol is defined to a non-zero value on hosts | |
5908 | whose filesystems belong to the MS-DOS/MS-Windows family. Use this | |
5909 | symbol to write conditional code which should only be compiled for | |
5910 | such hosts. | |
5911 | ||
5912 | @findex IS_DIR_SEPARATOR | |
4be31470 | 5913 | @item IS_DIR_SEPARATOR (@var{c}) |
dab11f21 EZ |
5914 | Evaluates to a non-zero value if @var{c} is a directory separator |
5915 | character. On Unix and GNU/Linux systems, only a slash @file{/} is | |
5916 | such a character, but on Windows, both @file{/} and @file{\} will | |
5917 | pass. | |
5918 | ||
5919 | @findex IS_ABSOLUTE_PATH | |
5920 | @item IS_ABSOLUTE_PATH (@var{file}) | |
5921 | Evaluates to a non-zero value if @var{file} is an absolute file name. | |
5922 | For Unix and GNU/Linux hosts, a name which begins with a slash | |
5923 | @file{/} is absolute. On DOS and Windows, @file{d:/foo} and | |
5924 | @file{x:\bar} are also absolute file names. | |
5925 | ||
5926 | @findex FILENAME_CMP | |
5927 | @item FILENAME_CMP (@var{f1}, @var{f2}) | |
5928 | Calls a function which compares file names @var{f1} and @var{f2} as | |
5929 | appropriate for the underlying host filesystem. For Posix systems, | |
5930 | this simply calls @code{strcmp}; on case-insensitive filesystems it | |
5931 | will call @code{strcasecmp} instead. | |
5932 | ||
5933 | @findex DIRNAME_SEPARATOR | |
5934 | @item DIRNAME_SEPARATOR | |
5935 | Evaluates to a character which separates directories in | |
5936 | @code{PATH}-style lists, typically held in environment variables. | |
5937 | This character is @samp{:} on Unix, @samp{;} on DOS and Windows. | |
5938 | ||
5939 | @findex SLASH_STRING | |
5940 | @item SLASH_STRING | |
5941 | This evaluates to a constant string you should use to produce an | |
5942 | absolute filename from leading directories and the file's basename. | |
5943 | @code{SLASH_STRING} is @code{"/"} on most systems, but might be | |
5944 | @code{"\\"} for some Windows-based ports. | |
5945 | @end table | |
5946 | ||
5947 | In addition to using these macros, be sure to use portable library | |
5948 | functions whenever possible. For example, to extract a directory or a | |
5949 | basename part from a file name, use the @code{dirname} and | |
5950 | @code{basename} library functions (available in @code{libiberty} for | |
5951 | platforms which don't provide them), instead of searching for a slash | |
5952 | with @code{strrchr}. | |
5953 | ||
25822942 DB |
5954 | Another way to generalize @value{GDBN} along a particular interface is with an |
5955 | attribute struct. For example, @value{GDBN} has been generalized to handle | |
56caf160 EZ |
5956 | multiple kinds of remote interfaces---not by @code{#ifdef}s everywhere, but |
5957 | by defining the @code{target_ops} structure and having a current target (as | |
c906108c SS |
5958 | well as a stack of targets below it, for memory references). Whenever |
5959 | something needs to be done that depends on which remote interface we are | |
56caf160 EZ |
5960 | using, a flag in the current target_ops structure is tested (e.g., |
5961 | @code{target_has_stack}), or a function is called through a pointer in the | |
c906108c | 5962 | current target_ops structure. In this way, when a new remote interface |
56caf160 | 5963 | is added, only one module needs to be touched---the one that actually |
c906108c SS |
5964 | implements the new remote interface. Other examples of |
5965 | attribute-structs are BFD access to multiple kinds of object file | |
25822942 | 5966 | formats, or @value{GDBN}'s access to multiple source languages. |
c906108c | 5967 | |
56caf160 EZ |
5968 | Please avoid duplicating code. For example, in @value{GDBN} 3.x all |
5969 | the code interfacing between @code{ptrace} and the rest of | |
5970 | @value{GDBN} was duplicated in @file{*-dep.c}, and so changing | |
5971 | something was very painful. In @value{GDBN} 4.x, these have all been | |
5972 | consolidated into @file{infptrace.c}. @file{infptrace.c} can deal | |
5973 | with variations between systems the same way any system-independent | |
5974 | file would (hooks, @code{#if defined}, etc.), and machines which are | |
5975 | radically different don't need to use @file{infptrace.c} at all. | |
c906108c | 5976 | |
af6c57ea AC |
5977 | All debugging code must be controllable using the @samp{set debug |
5978 | @var{module}} command. Do not use @code{printf} to print trace | |
5979 | messages. Use @code{fprintf_unfiltered(gdb_stdlog, ...}. Do not use | |
5980 | @code{#ifdef DEBUG}. | |
5981 | ||
c906108c | 5982 | |
8487521e | 5983 | @node Porting GDB |
c906108c | 5984 | |
25822942 | 5985 | @chapter Porting @value{GDBN} |
56caf160 | 5986 | @cindex porting to new machines |
c906108c | 5987 | |
56caf160 EZ |
5988 | Most of the work in making @value{GDBN} compile on a new machine is in |
5989 | specifying the configuration of the machine. This is done in a | |
5990 | dizzying variety of header files and configuration scripts, which we | |
5991 | hope to make more sensible soon. Let's say your new host is called an | |
5992 | @var{xyz} (e.g., @samp{sun4}), and its full three-part configuration | |
5993 | name is @code{@var{arch}-@var{xvend}-@var{xos}} (e.g., | |
5994 | @samp{sparc-sun-sunos4}). In particular: | |
c906108c | 5995 | |
56caf160 EZ |
5996 | @itemize @bullet |
5997 | @item | |
c906108c SS |
5998 | In the top level directory, edit @file{config.sub} and add @var{arch}, |
5999 | @var{xvend}, and @var{xos} to the lists of supported architectures, | |
6000 | vendors, and operating systems near the bottom of the file. Also, add | |
6001 | @var{xyz} as an alias that maps to | |
6002 | @code{@var{arch}-@var{xvend}-@var{xos}}. You can test your changes by | |
6003 | running | |
6004 | ||
474c8240 | 6005 | @smallexample |
c906108c | 6006 | ./config.sub @var{xyz} |
474c8240 | 6007 | @end smallexample |
56caf160 | 6008 | |
c906108c SS |
6009 | @noindent |
6010 | and | |
56caf160 | 6011 | |
474c8240 | 6012 | @smallexample |
c906108c | 6013 | ./config.sub @code{@var{arch}-@var{xvend}-@var{xos}} |
474c8240 | 6014 | @end smallexample |
56caf160 | 6015 | |
c906108c SS |
6016 | @noindent |
6017 | which should both respond with @code{@var{arch}-@var{xvend}-@var{xos}} | |
6018 | and no error messages. | |
6019 | ||
56caf160 | 6020 | @noindent |
c906108c SS |
6021 | You need to port BFD, if that hasn't been done already. Porting BFD is |
6022 | beyond the scope of this manual. | |
6023 | ||
56caf160 | 6024 | @item |
25822942 | 6025 | To configure @value{GDBN} itself, edit @file{gdb/configure.host} to recognize |
c906108c SS |
6026 | your system and set @code{gdb_host} to @var{xyz}, and (unless your |
6027 | desired target is already available) also edit @file{gdb/configure.tgt}, | |
6028 | setting @code{gdb_target} to something appropriate (for instance, | |
6029 | @var{xyz}). | |
6030 | ||
7fd60527 AC |
6031 | @emph{Maintainer's note: Work in progress. The file |
6032 | @file{gdb/configure.host} originally needed to be modified when either a | |
6033 | new native target or a new host machine was being added to @value{GDBN}. | |
6034 | Recent changes have removed this requirement. The file now only needs | |
6035 | to be modified when adding a new native configuration. This will likely | |
6036 | changed again in the future.} | |
6037 | ||
56caf160 | 6038 | @item |
25822942 | 6039 | Finally, you'll need to specify and define @value{GDBN}'s host-, native-, and |
c906108c SS |
6040 | target-dependent @file{.h} and @file{.c} files used for your |
6041 | configuration. | |
56caf160 | 6042 | @end itemize |
c906108c | 6043 | |
d52fe014 AC |
6044 | @node Versions and Branches |
6045 | @chapter Versions and Branches | |
8973da3a | 6046 | |
d52fe014 | 6047 | @section Versions |
8973da3a | 6048 | |
d52fe014 AC |
6049 | @value{GDBN}'s version is determined by the file |
6050 | @file{gdb/version.in} and takes one of the following forms: | |
fb0ff88f | 6051 | |
d52fe014 AC |
6052 | @table @asis |
6053 | @item @var{major}.@var{minor} | |
6054 | @itemx @var{major}.@var{minor}.@var{patchlevel} | |
53531fc1 AC |
6055 | an official release (e.g., 6.2 or 6.2.1) |
6056 | @item @var{major}.@var{minor}.@var{patchlevel}.@var{YYYY}@var{MM}@var{DD} | |
6057 | a snapshot taken at @var{YYYY}-@var{MM}-@var{DD}-gmt (e.g., | |
6058 | 6.1.50.20020302, 6.1.90.20020304, or 6.1.0.20020308) | |
6059 | @item @var{major}.@var{minor}.@var{patchlevel}.@var{YYYY}@var{MM}@var{DD}-cvs | |
6060 | a @sc{cvs} check out drawn on @var{YYYY}-@var{MM}-@var{DD} (e.g., | |
6061 | 6.1.50.20020302-cvs, 6.1.90.20020304-cvs, or 6.1.0.20020308-cvs) | |
6062 | @item @var{major}.@var{minor}.@var{patchlevel}.@var{YYYY}@var{MM}@var{DD} (@var{vendor}) | |
d52fe014 | 6063 | a vendor specific release of @value{GDBN}, that while based on@* |
53531fc1 AC |
6064 | @var{major}.@var{minor}.@var{patchlevel}.@var{YYYY}@var{MM}@var{DD}, |
6065 | may include additional changes | |
d52fe014 | 6066 | @end table |
fb0ff88f | 6067 | |
d52fe014 AC |
6068 | @value{GDBN}'s mainline uses the @var{major} and @var{minor} version |
6069 | numbers from the most recent release branch, with a @var{patchlevel} | |
53531fc1 AC |
6070 | of 50. At the time each new release branch is created, the mainline's |
6071 | @var{major} and @var{minor} version numbers are updated. | |
fb0ff88f | 6072 | |
53531fc1 AC |
6073 | @value{GDBN}'s release branch is similar. When the branch is cut, the |
6074 | @var{patchlevel} is changed from 50 to 90. As draft releases are | |
6075 | drawn from the branch, the @var{patchlevel} is incremented. Once the | |
6076 | first release (@var{major}.@var{minor}) has been made, the | |
6077 | @var{patchlevel} is set to 0 and updates have an incremented | |
6078 | @var{patchlevel}. | |
6079 | ||
6080 | For snapshots, and @sc{cvs} check outs, it is also possible to | |
6081 | identify the @sc{cvs} origin: | |
6082 | ||
6083 | @table @asis | |
6084 | @item @var{major}.@var{minor}.50.@var{YYYY}@var{MM}@var{DD} | |
6085 | drawn from the @sc{head} of mainline @sc{cvs} (e.g., 6.1.50.20020302) | |
6086 | @item @var{major}.@var{minor}.90.@var{YYYY}@var{MM}@var{DD} | |
6087 | @itemx @var{major}.@var{minor}.91.@var{YYYY}@var{MM}@var{DD} @dots{} | |
6088 | drawn from a release branch prior to the release (e.g., | |
6089 | 6.1.90.20020304) | |
6090 | @item @var{major}.@var{minor}.0.@var{YYYY}@var{MM}@var{DD} | |
6091 | @itemx @var{major}.@var{minor}.1.@var{YYYY}@var{MM}@var{DD} @dots{} | |
6092 | drawn from a release branch after the release (e.g., 6.2.0.20020308) | |
6093 | @end table | |
fb0ff88f | 6094 | |
d52fe014 AC |
6095 | If the previous @value{GDBN} version is 6.1 and the current version is |
6096 | 6.2, then, substituting 6 for @var{major} and 1 or 2 for @var{minor}, | |
6097 | here's an illustration of a typical sequence: | |
fb0ff88f | 6098 | |
d52fe014 AC |
6099 | @smallexample |
6100 | <HEAD> | |
6101 | | | |
53531fc1 | 6102 | 6.1.50.20020302-cvs |
d52fe014 | 6103 | | |
53531fc1 | 6104 | +--------------------------. |
d52fe014 | 6105 | | <gdb_6_2-branch> |
d52fe014 | 6106 | | | |
53531fc1 AC |
6107 | 6.2.50.20020303-cvs 6.1.90 (draft #1) |
6108 | | | | |
6109 | 6.2.50.20020304-cvs 6.1.90.20020304-cvs | |
6110 | | | | |
6111 | 6.2.50.20020305-cvs 6.1.91 (draft #2) | |
d52fe014 | 6112 | | | |
53531fc1 AC |
6113 | 6.2.50.20020306-cvs 6.1.91.20020306-cvs |
6114 | | | | |
6115 | 6.2.50.20020307-cvs 6.2 (release) | |
6116 | | | | |
6117 | 6.2.50.20020308-cvs 6.2.0.20020308-cvs | |
6118 | | | | |
6119 | 6.2.50.20020309-cvs 6.2.1 (update) | |
6120 | | | | |
6121 | 6.2.50.20020310-cvs <branch closed> | |
d52fe014 | 6122 | | |
53531fc1 | 6123 | 6.2.50.20020311-cvs |
d52fe014 | 6124 | | |
53531fc1 | 6125 | +--------------------------. |
d52fe014 | 6126 | | <gdb_6_3-branch> |
53531fc1 AC |
6127 | | | |
6128 | 6.3.50.20020312-cvs 6.2.90 (draft #1) | |
6129 | | | | |
d52fe014 | 6130 | @end smallexample |
fb0ff88f | 6131 | |
d52fe014 AC |
6132 | @section Release Branches |
6133 | @cindex Release Branches | |
fb0ff88f | 6134 | |
d52fe014 AC |
6135 | @value{GDBN} draws a release series (6.2, 6.2.1, @dots{}) from a |
6136 | single release branch, and identifies that branch using the @sc{cvs} | |
6137 | branch tags: | |
fb0ff88f | 6138 | |
d52fe014 AC |
6139 | @smallexample |
6140 | gdb_@var{major}_@var{minor}-@var{YYYY}@var{MM}@var{DD}-branchpoint | |
6141 | gdb_@var{major}_@var{minor}-branch | |
6142 | gdb_@var{major}_@var{minor}-@var{YYYY}@var{MM}@var{DD}-release | |
6143 | @end smallexample | |
6144 | ||
6145 | @emph{Pragmatics: To help identify the date at which a branch or | |
6146 | release is made, both the branchpoint and release tags include the | |
6147 | date that they are cut (@var{YYYY}@var{MM}@var{DD}) in the tag. The | |
6148 | branch tag, denoting the head of the branch, does not need this.} | |
6149 | ||
6150 | @section Vendor Branches | |
6151 | @cindex vendor branches | |
fb0ff88f AC |
6152 | |
6153 | To avoid version conflicts, vendors are expected to modify the file | |
6154 | @file{gdb/version.in} to include a vendor unique alphabetic identifier | |
6155 | (an official @value{GDBN} release never uses alphabetic characters in | |
d3e8051b | 6156 | its version identifier). E.g., @samp{6.2widgit2}, or @samp{6.2 (Widgit |
d52fe014 AC |
6157 | Inc Patch 2)}. |
6158 | ||
6159 | @section Experimental Branches | |
6160 | @cindex experimental branches | |
6161 | ||
6162 | @subsection Guidelines | |
6163 | ||
6164 | @value{GDBN} permits the creation of branches, cut from the @sc{cvs} | |
6165 | repository, for experimental development. Branches make it possible | |
6166 | for developers to share preliminary work, and maintainers to examine | |
6167 | significant new developments. | |
fb0ff88f | 6168 | |
d52fe014 | 6169 | The following are a set of guidelines for creating such branches: |
fb0ff88f | 6170 | |
d52fe014 AC |
6171 | @table @emph |
6172 | ||
6173 | @item a branch has an owner | |
6174 | The owner can set further policy for a branch, but may not change the | |
6175 | ground rules. In particular, they can set a policy for commits (be it | |
6176 | adding more reviewers or deciding who can commit). | |
6177 | ||
6178 | @item all commits are posted | |
6179 | All changes committed to a branch shall also be posted to | |
6180 | @email{gdb-patches@@sources.redhat.com, the @value{GDBN} patches | |
6181 | mailing list}. While commentary on such changes are encouraged, people | |
6182 | should remember that the changes only apply to a branch. | |
6183 | ||
6184 | @item all commits are covered by an assignment | |
6185 | This ensures that all changes belong to the Free Software Foundation, | |
6186 | and avoids the possibility that the branch may become contaminated. | |
6187 | ||
6188 | @item a branch is focused | |
6189 | A focused branch has a single objective or goal, and does not contain | |
6190 | unnecessary or irrelevant changes. Cleanups, where identified, being | |
6191 | be pushed into the mainline as soon as possible. | |
6192 | ||
6193 | @item a branch tracks mainline | |
6194 | This keeps the level of divergence under control. It also keeps the | |
6195 | pressure on developers to push cleanups and other stuff into the | |
6196 | mainline. | |
6197 | ||
6198 | @item a branch shall contain the entire @value{GDBN} module | |
6199 | The @value{GDBN} module @code{gdb} should be specified when creating a | |
6200 | branch (branches of individual files should be avoided). @xref{Tags}. | |
6201 | ||
6202 | @item a branch shall be branded using @file{version.in} | |
6203 | The file @file{gdb/version.in} shall be modified so that it identifies | |
6204 | the branch @var{owner} and branch @var{name}, e.g., | |
53531fc1 | 6205 | @samp{6.2.50.20030303_owner_name} or @samp{6.2 (Owner Name)}. |
d52fe014 AC |
6206 | |
6207 | @end table | |
fb0ff88f | 6208 | |
d52fe014 AC |
6209 | @subsection Tags |
6210 | @anchor{Tags} | |
fb0ff88f | 6211 | |
d52fe014 AC |
6212 | To simplify the identification of @value{GDBN} branches, the following |
6213 | branch tagging convention is strongly recommended: | |
fb0ff88f | 6214 | |
d52fe014 | 6215 | @table @code |
fb0ff88f | 6216 | |
d52fe014 AC |
6217 | @item @var{owner}_@var{name}-@var{YYYYMMDD}-branchpoint |
6218 | @itemx @var{owner}_@var{name}-@var{YYYYMMDD}-branch | |
6219 | The branch point and corresponding branch tag. @var{YYYYMMDD} is the | |
6220 | date that the branch was created. A branch is created using the | |
6221 | sequence: @anchor{experimental branch tags} | |
474c8240 | 6222 | @smallexample |
d52fe014 AC |
6223 | cvs rtag @var{owner}_@var{name}-@var{YYYYMMDD}-branchpoint gdb |
6224 | cvs rtag -b -r @var{owner}_@var{name}-@var{YYYYMMDD}-branchpoint \ | |
6225 | @var{owner}_@var{name}-@var{YYYYMMDD}-branch gdb | |
474c8240 | 6226 | @end smallexample |
fb0ff88f | 6227 | |
d52fe014 AC |
6228 | @item @var{owner}_@var{name}-@var{yyyymmdd}-mergepoint |
6229 | The tagged point, on the mainline, that was used when merging the branch | |
6230 | on @var{yyyymmdd}. To merge in all changes since the branch was cut, | |
6231 | use a command sequence like: | |
474c8240 | 6232 | @smallexample |
d52fe014 AC |
6233 | cvs rtag @var{owner}_@var{name}-@var{yyyymmdd}-mergepoint gdb |
6234 | cvs update \ | |
6235 | -j@var{owner}_@var{name}-@var{YYYYMMDD}-branchpoint | |
6236 | -j@var{owner}_@var{name}-@var{yyyymmdd}-mergepoint | |
474c8240 | 6237 | @end smallexample |
d52fe014 AC |
6238 | @noindent |
6239 | Similar sequences can be used to just merge in changes since the last | |
6240 | merge. | |
6241 | ||
6242 | @end table | |
fb0ff88f | 6243 | |
d52fe014 AC |
6244 | @noindent |
6245 | For further information on @sc{cvs}, see | |
6246 | @uref{http://www.gnu.org/software/cvs/, Concurrent Versions System}. | |
6247 | ||
55f6ca0f JB |
6248 | @node Start of New Year Procedure |
6249 | @chapter Start of New Year Procedure | |
6250 | @cindex new year procedure | |
6251 | ||
6252 | At the start of each new year, the following actions should be performed: | |
6253 | ||
6254 | @itemize @bullet | |
6255 | @item | |
6256 | Rotate the ChangeLog file | |
6257 | ||
6258 | The current @file{ChangeLog} file should be renamed into | |
6259 | @file{ChangeLog-YYYY} where YYYY is the year that has just passed. | |
6260 | A new @file{ChangeLog} file should be created, and its contents should | |
6261 | contain a reference to the previous ChangeLog. The following should | |
6262 | also be preserved at the end of the new ChangeLog, in order to provide | |
6263 | the appropriate settings when editing this file with Emacs: | |
6264 | @smallexample | |
6265 | Local Variables: | |
6266 | mode: change-log | |
6267 | left-margin: 8 | |
6268 | fill-column: 74 | |
6269 | version-control: never | |
6270 | End: | |
6271 | @end smallexample | |
6272 | ||
7f893741 JB |
6273 | @item |
6274 | Add an entry for the newly created ChangeLog file (@file{ChangeLog-YYYY}) | |
6275 | in @file{gdb/config/djgpp/fnchange.lst}. | |
6276 | ||
55f6ca0f JB |
6277 | @item |
6278 | Update the copyright year in the startup message | |
6279 | ||
6280 | Update the copyright year in file @file{top.c}, function | |
6281 | @code{print_gdb_version}. | |
6282 | @end itemize | |
6283 | ||
d52fe014 | 6284 | @node Releasing GDB |
fb0ff88f | 6285 | |
d52fe014 AC |
6286 | @chapter Releasing @value{GDBN} |
6287 | @cindex making a new release of gdb | |
fb0ff88f | 6288 | |
9bb0a4d8 AC |
6289 | @section Branch Commit Policy |
6290 | ||
6291 | The branch commit policy is pretty slack. @value{GDBN} releases 5.0, | |
6292 | 5.1 and 5.2 all used the below: | |
6293 | ||
6294 | @itemize @bullet | |
6295 | @item | |
6296 | The @file{gdb/MAINTAINERS} file still holds. | |
6297 | @item | |
6298 | Don't fix something on the branch unless/until it is also fixed in the | |
6299 | trunk. If this isn't possible, mentioning it in the @file{gdb/PROBLEMS} | |
4be31470 | 6300 | file is better than committing a hack. |
9bb0a4d8 AC |
6301 | @item |
6302 | When considering a patch for the branch, suggested criteria include: | |
6303 | Does it fix a build? Does it fix the sequence @kbd{break main; run} | |
6304 | when debugging a static binary? | |
6305 | @item | |
6306 | The further a change is from the core of @value{GDBN}, the less likely | |
6307 | the change will worry anyone (e.g., target specific code). | |
6308 | @item | |
6309 | Only post a proposal to change the core of @value{GDBN} after you've | |
6310 | sent individual bribes to all the people listed in the | |
6311 | @file{MAINTAINERS} file @t{;-)} | |
6312 | @end itemize | |
6313 | ||
6314 | @emph{Pragmatics: Provided updates are restricted to non-core | |
6315 | functionality there is little chance that a broken change will be fatal. | |
6316 | This means that changes such as adding a new architectures or (within | |
6317 | reason) support for a new host are considered acceptable.} | |
6318 | ||
6319 | ||
cbb09e6a | 6320 | @section Obsoleting code |
8973da3a | 6321 | |
8642bc8f | 6322 | Before anything else, poke the other developers (and around the source |
4be31470 EZ |
6323 | code) to see if there is anything that can be removed from @value{GDBN} |
6324 | (an old target, an unused file). | |
8973da3a | 6325 | |
8642bc8f | 6326 | Obsolete code is identified by adding an @code{OBSOLETE} prefix to every |
cbb09e6a AC |
6327 | line. Doing this means that it is easy to identify something that has |
6328 | been obsoleted when greping through the sources. | |
8973da3a | 6329 | |
cbb09e6a AC |
6330 | The process is done in stages --- this is mainly to ensure that the |
6331 | wider @value{GDBN} community has a reasonable opportunity to respond. | |
6332 | Remember, everything on the Internet takes a week. | |
8973da3a | 6333 | |
cbb09e6a | 6334 | @enumerate |
8973da3a | 6335 | @item |
cbb09e6a AC |
6336 | Post the proposal on @email{gdb@@sources.redhat.com, the GDB mailing |
6337 | list} Creating a bug report to track the task's state, is also highly | |
6338 | recommended. | |
8973da3a | 6339 | @item |
cbb09e6a | 6340 | Wait a week or so. |
8973da3a | 6341 | @item |
cbb09e6a AC |
6342 | Post the proposal on @email{gdb-announce@@sources.redhat.com, the GDB |
6343 | Announcement mailing list}. | |
8973da3a | 6344 | @item |
cbb09e6a | 6345 | Wait a week or so. |
8973da3a | 6346 | @item |
cbb09e6a AC |
6347 | Go through and edit all relevant files and lines so that they are |
6348 | prefixed with the word @code{OBSOLETE}. | |
6349 | @item | |
6350 | Wait until the next GDB version, containing this obsolete code, has been | |
6351 | released. | |
6352 | @item | |
6353 | Remove the obsolete code. | |
6354 | @end enumerate | |
6355 | ||
6356 | @noindent | |
6357 | @emph{Maintainer note: While removing old code is regrettable it is | |
6358 | hopefully better for @value{GDBN}'s long term development. Firstly it | |
6359 | helps the developers by removing code that is either no longer relevant | |
6360 | or simply wrong. Secondly since it removes any history associated with | |
6361 | the file (effectively clearing the slate) the developer has a much freer | |
6362 | hand when it comes to fixing broken files.} | |
8973da3a | 6363 | |
8973da3a | 6364 | |
9ae8b82c AC |
6365 | |
6366 | @section Before the Branch | |
8973da3a | 6367 | |
8642bc8f AC |
6368 | The most important objective at this stage is to find and fix simple |
6369 | changes that become a pain to track once the branch is created. For | |
6370 | instance, configuration problems that stop @value{GDBN} from even | |
6371 | building. If you can't get the problem fixed, document it in the | |
6372 | @file{gdb/PROBLEMS} file. | |
8973da3a | 6373 | |
9ae8b82c | 6374 | @subheading Prompt for @file{gdb/NEWS} |
8973da3a | 6375 | |
9ae8b82c AC |
6376 | People always forget. Send a post reminding them but also if you know |
6377 | something interesting happened add it yourself. The @code{schedule} | |
6378 | script will mention this in its e-mail. | |
8973da3a | 6379 | |
9ae8b82c | 6380 | @subheading Review @file{gdb/README} |
8973da3a | 6381 | |
9ae8b82c AC |
6382 | Grab one of the nightly snapshots and then walk through the |
6383 | @file{gdb/README} looking for anything that can be improved. The | |
6384 | @code{schedule} script will mention this in its e-mail. | |
8642bc8f AC |
6385 | |
6386 | @subheading Refresh any imported files. | |
8973da3a | 6387 | |
8642bc8f | 6388 | A number of files are taken from external repositories. They include: |
8973da3a | 6389 | |
8642bc8f AC |
6390 | @itemize @bullet |
6391 | @item | |
6392 | @file{texinfo/texinfo.tex} | |
6393 | @item | |
9ae8b82c AC |
6394 | @file{config.guess} et.@: al.@: (see the top-level @file{MAINTAINERS} |
6395 | file) | |
6396 | @item | |
6397 | @file{etc/standards.texi}, @file{etc/make-stds.texi} | |
8642bc8f AC |
6398 | @end itemize |
6399 | ||
9ae8b82c | 6400 | @subheading Check the ARI |
8642bc8f | 6401 | |
9ae8b82c AC |
6402 | @uref{http://sources.redhat.com/gdb/ari,,A.R.I.} is an @code{awk} script |
6403 | (Awk Regression Index ;-) that checks for a number of errors and coding | |
6404 | conventions. The checks include things like using @code{malloc} instead | |
6405 | of @code{xmalloc} and file naming problems. There shouldn't be any | |
6406 | regressions. | |
8642bc8f | 6407 | |
9ae8b82c | 6408 | @subsection Review the bug data base |
8642bc8f | 6409 | |
9ae8b82c | 6410 | Close anything obviously fixed. |
8642bc8f | 6411 | |
9ae8b82c | 6412 | @subsection Check all cross targets build |
8642bc8f | 6413 | |
9ae8b82c | 6414 | The targets are listed in @file{gdb/MAINTAINERS}. |
8642bc8f | 6415 | |
8642bc8f | 6416 | |
30107679 | 6417 | @section Cut the Branch |
8642bc8f | 6418 | |
30107679 | 6419 | @subheading Create the branch |
8642bc8f | 6420 | |
474c8240 | 6421 | @smallexample |
30107679 AC |
6422 | $ u=5.1 |
6423 | $ v=5.2 | |
6424 | $ V=`echo $v | sed 's/\./_/g'` | |
6425 | $ D=`date -u +%Y-%m-%d` | |
6426 | $ echo $u $V $D | |
6427 | 5.1 5_2 2002-03-03 | |
6428 | $ echo cvs -f -d :ext:sources.redhat.com:/cvs/src rtag \ | |
b247355e | 6429 | -D $D-gmt gdb_$V-$D-branchpoint insight |
30107679 | 6430 | cvs -f -d :ext:sources.redhat.com:/cvs/src rtag |
b247355e | 6431 | -D 2002-03-03-gmt gdb_5_2-2002-03-03-branchpoint insight |
30107679 AC |
6432 | $ ^echo ^^ |
6433 | ... | |
6434 | $ echo cvs -f -d :ext:sources.redhat.com:/cvs/src rtag \ | |
b247355e | 6435 | -b -r gdb_$V-$D-branchpoint gdb_$V-branch insight |
30107679 | 6436 | cvs -f -d :ext:sources.redhat.com:/cvs/src rtag \ |
b247355e | 6437 | -b -r gdb_5_2-2002-03-03-branchpoint gdb_5_2-branch insight |
30107679 AC |
6438 | $ ^echo ^^ |
6439 | ... | |
8642bc8f | 6440 | $ |
474c8240 | 6441 | @end smallexample |
8642bc8f AC |
6442 | |
6443 | @itemize @bullet | |
6444 | @item | |
b247355e | 6445 | By using @kbd{-D YYYY-MM-DD-gmt}, the branch is forced to an exact |
30107679 AC |
6446 | date/time. |
6447 | @item | |
b247355e | 6448 | The trunk is first tagged so that the branch point can easily be found. |
30107679 | 6449 | @item |
b247355e | 6450 | Insight, which includes @value{GDBN}, is tagged at the same time. |
8642bc8f | 6451 | @item |
b247355e | 6452 | @file{version.in} gets bumped to avoid version number conflicts. |
8642bc8f | 6453 | @item |
b247355e | 6454 | The reading of @file{.cvsrc} is disabled using @file{-f}. |
30107679 AC |
6455 | @end itemize |
6456 | ||
6457 | @subheading Update @file{version.in} | |
6458 | ||
6459 | @smallexample | |
6460 | $ u=5.1 | |
6461 | $ v=5.2 | |
6462 | $ V=`echo $v | sed 's/\./_/g'` | |
6463 | $ echo $u $v$V | |
6464 | 5.1 5_2 | |
6465 | $ cd /tmp | |
6466 | $ echo cvs -f -d :ext:sources.redhat.com:/cvs/src co \ | |
6467 | -r gdb_$V-branch src/gdb/version.in | |
6468 | cvs -f -d :ext:sources.redhat.com:/cvs/src co | |
6469 | -r gdb_5_2-branch src/gdb/version.in | |
6470 | $ ^echo ^^ | |
6471 | U src/gdb/version.in | |
6472 | $ cd src/gdb | |
6473 | $ echo $u.90-0000-00-00-cvs > version.in | |
6474 | $ cat version.in | |
6475 | 5.1.90-0000-00-00-cvs | |
6476 | $ cvs -f commit version.in | |
6477 | @end smallexample | |
6478 | ||
6479 | @itemize @bullet | |
6480 | @item | |
6481 | @file{0000-00-00} is used as a date to pump prime the version.in update | |
b247355e | 6482 | mechanism. |
30107679 AC |
6483 | @item |
6484 | @file{.90} and the previous branch version are used as fairly arbitrary | |
b247355e | 6485 | initial branch version number. |
8642bc8f AC |
6486 | @end itemize |
6487 | ||
8642bc8f AC |
6488 | |
6489 | @subheading Update the web and news pages | |
6490 | ||
30107679 AC |
6491 | Something? |
6492 | ||
8642bc8f AC |
6493 | @subheading Tweak cron to track the new branch |
6494 | ||
30107679 AC |
6495 | The file @file{gdbadmin/cron/crontab} contains gdbadmin's cron table. |
6496 | This file needs to be updated so that: | |
6497 | ||
6498 | @itemize @bullet | |
6499 | @item | |
b247355e | 6500 | A daily timestamp is added to the file @file{version.in}. |
30107679 | 6501 | @item |
b247355e | 6502 | The new branch is included in the snapshot process. |
30107679 AC |
6503 | @end itemize |
6504 | ||
6505 | @noindent | |
6506 | See the file @file{gdbadmin/cron/README} for how to install the updated | |
6507 | cron table. | |
6508 | ||
6509 | The file @file{gdbadmin/ss/README} should also be reviewed to reflect | |
6510 | any changes. That file is copied to both the branch/ and current/ | |
6511 | snapshot directories. | |
6512 | ||
6513 | ||
6514 | @subheading Update the NEWS and README files | |
6515 | ||
6516 | The @file{NEWS} file needs to be updated so that on the branch it refers | |
6517 | to @emph{changes in the current release} while on the trunk it also | |
6518 | refers to @emph{changes since the current release}. | |
6519 | ||
6520 | The @file{README} file needs to be updated so that it refers to the | |
6521 | current release. | |
6522 | ||
6523 | @subheading Post the branch info | |
6524 | ||
6525 | Send an announcement to the mailing lists: | |
6526 | ||
6527 | @itemize @bullet | |
6528 | @item | |
6529 | @email{gdb-announce@@sources.redhat.com, GDB Announcement mailing list} | |
6530 | @item | |
d3e8051b EZ |
6531 | @email{gdb@@sources.redhat.com, GDB Discussion mailing list} and |
6532 | @email{gdb-testers@@sources.redhat.com, GDB Testers mailing list} | |
16737d73 | 6533 | @end itemize |
30107679 AC |
6534 | |
6535 | @emph{Pragmatics: The branch creation is sent to the announce list to | |
6536 | ensure that people people not subscribed to the higher volume discussion | |
6537 | list are alerted.} | |
6538 | ||
6539 | The announcement should include: | |
6540 | ||
6541 | @itemize @bullet | |
6542 | @item | |
b247355e | 6543 | The branch tag. |
30107679 | 6544 | @item |
b247355e | 6545 | How to check out the branch using CVS. |
30107679 | 6546 | @item |
b247355e | 6547 | The date/number of weeks until the release. |
30107679 | 6548 | @item |
b247355e | 6549 | The branch commit policy still holds. |
16737d73 | 6550 | @end itemize |
30107679 | 6551 | |
8642bc8f AC |
6552 | @section Stabilize the branch |
6553 | ||
6554 | Something goes here. | |
6555 | ||
6556 | @section Create a Release | |
6557 | ||
0816590b AC |
6558 | The process of creating and then making available a release is broken |
6559 | down into a number of stages. The first part addresses the technical | |
6560 | process of creating a releasable tar ball. The later stages address the | |
6561 | process of releasing that tar ball. | |
8973da3a | 6562 | |
0816590b AC |
6563 | When making a release candidate just the first section is needed. |
6564 | ||
6565 | @subsection Create a release candidate | |
6566 | ||
6567 | The objective at this stage is to create a set of tar balls that can be | |
6568 | made available as a formal release (or as a less formal release | |
6569 | candidate). | |
6570 | ||
6571 | @subsubheading Freeze the branch | |
6572 | ||
6573 | Send out an e-mail notifying everyone that the branch is frozen to | |
6574 | @email{gdb-patches@@sources.redhat.com}. | |
6575 | ||
6576 | @subsubheading Establish a few defaults. | |
8973da3a | 6577 | |
474c8240 | 6578 | @smallexample |
0816590b AC |
6579 | $ b=gdb_5_2-branch |
6580 | $ v=5.2 | |
8642bc8f AC |
6581 | $ t=/sourceware/snapshot-tmp/gdbadmin-tmp |
6582 | $ echo $t/$b/$v | |
0816590b | 6583 | /sourceware/snapshot-tmp/gdbadmin-tmp/gdb_5_2-branch/5.2 |
8642bc8f AC |
6584 | $ mkdir -p $t/$b/$v |
6585 | $ cd $t/$b/$v | |
6586 | $ pwd | |
0816590b | 6587 | /sourceware/snapshot-tmp/gdbadmin-tmp/gdb_5_2-branch/5.2 |
8973da3a AC |
6588 | $ which autoconf |
6589 | /home/gdbadmin/bin/autoconf | |
8642bc8f | 6590 | $ |
474c8240 | 6591 | @end smallexample |
8973da3a | 6592 | |
0816590b AC |
6593 | @noindent |
6594 | Notes: | |
8973da3a | 6595 | |
0816590b AC |
6596 | @itemize @bullet |
6597 | @item | |
6598 | Check the @code{autoconf} version carefully. You want to be using the | |
4a2b4636 JB |
6599 | version taken from the @file{binutils} snapshot directory, which can be |
6600 | found at @uref{ftp://sources.redhat.com/pub/binutils/}. It is very | |
0816590b AC |
6601 | unlikely that a system installed version of @code{autoconf} (e.g., |
6602 | @file{/usr/bin/autoconf}) is correct. | |
6603 | @end itemize | |
6604 | ||
6605 | @subsubheading Check out the relevant modules: | |
8973da3a | 6606 | |
474c8240 | 6607 | @smallexample |
b247355e | 6608 | $ for m in gdb insight |
8642bc8f | 6609 | do |
8973da3a AC |
6610 | ( mkdir -p $m && cd $m && cvs -q -f -d /cvs/src co -P -r $b $m ) |
6611 | done | |
8642bc8f | 6612 | $ |
474c8240 | 6613 | @end smallexample |
8973da3a | 6614 | |
0816590b AC |
6615 | @noindent |
6616 | Note: | |
8642bc8f | 6617 | |
0816590b AC |
6618 | @itemize @bullet |
6619 | @item | |
6620 | The reading of @file{.cvsrc} is disabled (@file{-f}) so that there isn't | |
6621 | any confusion between what is written here and what your local | |
6622 | @code{cvs} really does. | |
6623 | @end itemize | |
6624 | ||
6625 | @subsubheading Update relevant files. | |
8973da3a | 6626 | |
0816590b AC |
6627 | @table @file |
6628 | ||
6629 | @item gdb/NEWS | |
8642bc8f AC |
6630 | |
6631 | Major releases get their comments added as part of the mainline. Minor | |
6632 | releases should probably mention any significant bugs that were fixed. | |
6633 | ||
0816590b | 6634 | Don't forget to include the @file{ChangeLog} entry. |
8973da3a | 6635 | |
474c8240 | 6636 | @smallexample |
8642bc8f AC |
6637 | $ emacs gdb/src/gdb/NEWS |
6638 | ... | |
6639 | c-x 4 a | |
6640 | ... | |
6641 | c-x c-s c-x c-c | |
6642 | $ cp gdb/src/gdb/NEWS insight/src/gdb/NEWS | |
6643 | $ cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog | |
474c8240 | 6644 | @end smallexample |
8973da3a | 6645 | |
0816590b AC |
6646 | @item gdb/README |
6647 | ||
6648 | You'll need to update: | |
8973da3a | 6649 | |
0816590b AC |
6650 | @itemize @bullet |
6651 | @item | |
b247355e | 6652 | The version. |
0816590b | 6653 | @item |
b247355e | 6654 | The update date. |
0816590b | 6655 | @item |
b247355e | 6656 | Who did it. |
0816590b | 6657 | @end itemize |
8973da3a | 6658 | |
474c8240 | 6659 | @smallexample |
8642bc8f AC |
6660 | $ emacs gdb/src/gdb/README |
6661 | ... | |
8973da3a | 6662 | c-x 4 a |
8642bc8f | 6663 | ... |
8973da3a | 6664 | c-x c-s c-x c-c |
8642bc8f AC |
6665 | $ cp gdb/src/gdb/README insight/src/gdb/README |
6666 | $ cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog | |
474c8240 | 6667 | @end smallexample |
8973da3a | 6668 | |
0816590b AC |
6669 | @emph{Maintainer note: Hopefully the @file{README} file was reviewed |
6670 | before the initial branch was cut so just a simple substitute is needed | |
6671 | to get it updated.} | |
8973da3a | 6672 | |
8642bc8f AC |
6673 | @emph{Maintainer note: Other projects generate @file{README} and |
6674 | @file{INSTALL} from the core documentation. This might be worth | |
6675 | pursuing.} | |
8973da3a | 6676 | |
0816590b | 6677 | @item gdb/version.in |
8973da3a | 6678 | |
474c8240 | 6679 | @smallexample |
8642bc8f | 6680 | $ echo $v > gdb/src/gdb/version.in |
0816590b AC |
6681 | $ cat gdb/src/gdb/version.in |
6682 | 5.2 | |
8642bc8f | 6683 | $ emacs gdb/src/gdb/version.in |
8973da3a AC |
6684 | ... |
6685 | c-x 4 a | |
0816590b | 6686 | ... Bump to version ... |
8973da3a | 6687 | c-x c-s c-x c-c |
8642bc8f AC |
6688 | $ cp gdb/src/gdb/version.in insight/src/gdb/version.in |
6689 | $ cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog | |
474c8240 | 6690 | @end smallexample |
8973da3a | 6691 | |
0816590b AC |
6692 | @end table |
6693 | ||
6694 | @subsubheading Do the dirty work | |
6695 | ||
6696 | This is identical to the process used to create the daily snapshot. | |
8973da3a | 6697 | |
4ce8657e MC |
6698 | @smallexample |
6699 | $ for m in gdb insight | |
6700 | do | |
6701 | ( cd $m/src && gmake -f src-release $m.tar ) | |
6702 | done | |
4ce8657e MC |
6703 | @end smallexample |
6704 | ||
6705 | If the top level source directory does not have @file{src-release} | |
6706 | (@value{GDBN} version 5.3.1 or earlier), try these commands instead: | |
6707 | ||
474c8240 | 6708 | @smallexample |
0816590b | 6709 | $ for m in gdb insight |
8642bc8f | 6710 | do |
0816590b | 6711 | ( cd $m/src && gmake -f Makefile.in $m.tar ) |
8973da3a | 6712 | done |
474c8240 | 6713 | @end smallexample |
8973da3a | 6714 | |
0816590b | 6715 | @subsubheading Check the source files |
8642bc8f | 6716 | |
0816590b | 6717 | You're looking for files that have mysteriously disappeared. |
8642bc8f AC |
6718 | @kbd{distclean} has the habit of deleting files it shouldn't. Watch out |
6719 | for the @file{version.in} update @kbd{cronjob}. | |
8973da3a | 6720 | |
474c8240 | 6721 | @smallexample |
8642bc8f AC |
6722 | $ ( cd gdb/src && cvs -f -q -n update ) |
6723 | M djunpack.bat | |
0816590b | 6724 | ? gdb-5.1.91.tar |
8642bc8f | 6725 | ? proto-toplev |
0816590b | 6726 | @dots{} lots of generated files @dots{} |
8642bc8f AC |
6727 | M gdb/ChangeLog |
6728 | M gdb/NEWS | |
6729 | M gdb/README | |
6730 | M gdb/version.in | |
0816590b | 6731 | @dots{} lots of generated files @dots{} |
8642bc8f | 6732 | $ |
474c8240 | 6733 | @end smallexample |
8973da3a | 6734 | |
0816590b | 6735 | @noindent |
8642bc8f AC |
6736 | @emph{Don't worry about the @file{gdb.info-??} or |
6737 | @file{gdb/p-exp.tab.c}. They were generated (and yes @file{gdb.info-1} | |
6738 | was also generated only something strange with CVS means that they | |
d3e8051b | 6739 | didn't get suppressed). Fixing it would be nice though.} |
8973da3a | 6740 | |
0816590b | 6741 | @subsubheading Create compressed versions of the release |
8973da3a | 6742 | |
474c8240 | 6743 | @smallexample |
0816590b AC |
6744 | $ cp */src/*.tar . |
6745 | $ cp */src/*.bz2 . | |
6746 | $ ls -F | |
b247355e | 6747 | gdb/ gdb-5.2.tar insight/ insight-5.2.tar |
0816590b AC |
6748 | $ for m in gdb insight |
6749 | do | |
6750 | bzip2 -v -9 -c $m-$v.tar > $m-$v.tar.bz2 | |
6751 | gzip -v -9 -c $m-$v.tar > $m-$v.tar.gz | |
6752 | done | |
6753 | $ | |
474c8240 | 6754 | @end smallexample |
8973da3a | 6755 | |
0816590b AC |
6756 | @noindent |
6757 | Note: | |
6758 | ||
6759 | @itemize @bullet | |
6760 | @item | |
6761 | A pipe such as @kbd{bunzip2 < xxx.bz2 | gzip -9 > xxx.gz} is not since, | |
6762 | in that mode, @code{gzip} does not know the name of the file and, hence, | |
6763 | can not include it in the compressed file. This is also why the release | |
6764 | process runs @code{tar} and @code{bzip2} as separate passes. | |
6765 | @end itemize | |
6766 | ||
6767 | @subsection Sanity check the tar ball | |
8973da3a | 6768 | |
0816590b | 6769 | Pick a popular machine (Solaris/PPC?) and try the build on that. |
8973da3a | 6770 | |
0816590b AC |
6771 | @smallexample |
6772 | $ bunzip2 < gdb-5.2.tar.bz2 | tar xpf - | |
6773 | $ cd gdb-5.2 | |
6774 | $ ./configure | |
6775 | $ make | |
6776 | @dots{} | |
6777 | $ ./gdb/gdb ./gdb/gdb | |
6778 | GNU gdb 5.2 | |
6779 | @dots{} | |
6780 | (gdb) b main | |
6781 | Breakpoint 1 at 0x80732bc: file main.c, line 734. | |
6782 | (gdb) run | |
6783 | Starting program: /tmp/gdb-5.2/gdb/gdb | |
6784 | ||
6785 | Breakpoint 1, main (argc=1, argv=0xbffff8b4) at main.c:734 | |
6786 | 734 catch_errors (captured_main, &args, "", RETURN_MASK_ALL); | |
6787 | (gdb) print args | |
6788 | $1 = @{argc = 136426532, argv = 0x821b7f0@} | |
6789 | (gdb) | |
6790 | @end smallexample | |
8973da3a | 6791 | |
0816590b | 6792 | @subsection Make a release candidate available |
8973da3a | 6793 | |
0816590b | 6794 | If this is a release candidate then the only remaining steps are: |
8642bc8f | 6795 | |
0816590b AC |
6796 | @enumerate |
6797 | @item | |
6798 | Commit @file{version.in} and @file{ChangeLog} | |
6799 | @item | |
6800 | Tweak @file{version.in} (and @file{ChangeLog} to read | |
6801 | @var{L}.@var{M}.@var{N}-0000-00-00-cvs so that the version update | |
6802 | process can restart. | |
6803 | @item | |
6804 | Make the release candidate available in | |
6805 | @uref{ftp://sources.redhat.com/pub/gdb/snapshots/branch} | |
6806 | @item | |
6807 | Notify the relevant mailing lists ( @email{gdb@@sources.redhat.com} and | |
6808 | @email{gdb-testers@@sources.redhat.com} that the candidate is available. | |
6809 | @end enumerate | |
8642bc8f | 6810 | |
0816590b | 6811 | @subsection Make a formal release available |
8642bc8f | 6812 | |
0816590b | 6813 | (And you thought all that was required was to post an e-mail.) |
8642bc8f | 6814 | |
0816590b | 6815 | @subsubheading Install on sware |
8642bc8f | 6816 | |
0816590b | 6817 | Copy the new files to both the release and the old release directory: |
8642bc8f | 6818 | |
474c8240 | 6819 | @smallexample |
0816590b | 6820 | $ cp *.bz2 *.gz ~ftp/pub/gdb/old-releases/ |
8642bc8f | 6821 | $ cp *.bz2 *.gz ~ftp/pub/gdb/releases |
474c8240 | 6822 | @end smallexample |
8642bc8f | 6823 | |
0816590b AC |
6824 | @noindent |
6825 | Clean up the releases directory so that only the most recent releases | |
6826 | are available (e.g. keep 5.2 and 5.2.1 but remove 5.1): | |
6827 | ||
6828 | @smallexample | |
6829 | $ cd ~ftp/pub/gdb/releases | |
6830 | $ rm @dots{} | |
6831 | @end smallexample | |
6832 | ||
6833 | @noindent | |
6834 | Update the file @file{README} and @file{.message} in the releases | |
6835 | directory: | |
6836 | ||
6837 | @smallexample | |
6838 | $ vi README | |
6839 | @dots{} | |
6840 | $ rm -f .message | |
6841 | $ ln README .message | |
6842 | @end smallexample | |
8642bc8f | 6843 | |
0816590b | 6844 | @subsubheading Update the web pages. |
8973da3a | 6845 | |
0816590b AC |
6846 | @table @file |
6847 | ||
6848 | @item htdocs/download/ANNOUNCEMENT | |
6849 | This file, which is posted as the official announcement, includes: | |
8973da3a AC |
6850 | @itemize @bullet |
6851 | @item | |
b247355e | 6852 | General announcement. |
8642bc8f | 6853 | @item |
0816590b AC |
6854 | News. If making an @var{M}.@var{N}.1 release, retain the news from |
6855 | earlier @var{M}.@var{N} release. | |
8973da3a | 6856 | @item |
b247355e | 6857 | Errata. |
0816590b AC |
6858 | @end itemize |
6859 | ||
6860 | @item htdocs/index.html | |
6861 | @itemx htdocs/news/index.html | |
6862 | @itemx htdocs/download/index.html | |
6863 | These files include: | |
6864 | @itemize @bullet | |
8642bc8f | 6865 | @item |
b247355e | 6866 | Announcement of the most recent release. |
8642bc8f | 6867 | @item |
b247355e | 6868 | News entry (remember to update both the top level and the news directory). |
8973da3a | 6869 | @end itemize |
0816590b | 6870 | These pages also need to be regenerate using @code{index.sh}. |
8973da3a | 6871 | |
0816590b | 6872 | @item download/onlinedocs/ |
8642bc8f AC |
6873 | You need to find the magic command that is used to generate the online |
6874 | docs from the @file{.tar.bz2}. The best way is to look in the output | |
0816590b | 6875 | from one of the nightly @code{cron} jobs and then just edit accordingly. |
8642bc8f AC |
6876 | Something like: |
6877 | ||
474c8240 | 6878 | @smallexample |
8642bc8f | 6879 | $ ~/ss/update-web-docs \ |
0816590b | 6880 | ~ftp/pub/gdb/releases/gdb-5.2.tar.bz2 \ |
8642bc8f | 6881 | $PWD/www \ |
0816590b | 6882 | /www/sourceware/htdocs/gdb/download/onlinedocs \ |
8642bc8f | 6883 | gdb |
474c8240 | 6884 | @end smallexample |
8642bc8f | 6885 | |
0816590b AC |
6886 | @item download/ari/ |
6887 | Just like the online documentation. Something like: | |
8642bc8f | 6888 | |
0816590b AC |
6889 | @smallexample |
6890 | $ /bin/sh ~/ss/update-web-ari \ | |
6891 | ~ftp/pub/gdb/releases/gdb-5.2.tar.bz2 \ | |
6892 | $PWD/www \ | |
6893 | /www/sourceware/htdocs/gdb/download/ari \ | |
6894 | gdb | |
6895 | @end smallexample | |
6896 | ||
6897 | @end table | |
6898 | ||
6899 | @subsubheading Shadow the pages onto gnu | |
6900 | ||
6901 | Something goes here. | |
6902 | ||
6903 | ||
6904 | @subsubheading Install the @value{GDBN} tar ball on GNU | |
6905 | ||
6906 | At the time of writing, the GNU machine was @kbd{gnudist.gnu.org} in | |
6907 | @file{~ftp/gnu/gdb}. | |
6908 | ||
6909 | @subsubheading Make the @file{ANNOUNCEMENT} | |
6910 | ||
6911 | Post the @file{ANNOUNCEMENT} file you created above to: | |
8642bc8f AC |
6912 | |
6913 | @itemize @bullet | |
6914 | @item | |
6915 | @email{gdb-announce@@sources.redhat.com, GDB Announcement mailing list} | |
6916 | @item | |
0816590b AC |
6917 | @email{info-gnu@@gnu.org, General GNU Announcement list} (but delay it a |
6918 | day or so to let things get out) | |
6919 | @item | |
6920 | @email{bug-gdb@@gnu.org, GDB Bug Report mailing list} | |
8642bc8f AC |
6921 | @end itemize |
6922 | ||
0816590b | 6923 | @subsection Cleanup |
8642bc8f | 6924 | |
0816590b | 6925 | The release is out but you're still not finished. |
8642bc8f | 6926 | |
0816590b | 6927 | @subsubheading Commit outstanding changes |
8642bc8f | 6928 | |
0816590b | 6929 | In particular you'll need to commit any changes to: |
8642bc8f AC |
6930 | |
6931 | @itemize @bullet | |
6932 | @item | |
6933 | @file{gdb/ChangeLog} | |
6934 | @item | |
6935 | @file{gdb/version.in} | |
6936 | @item | |
6937 | @file{gdb/NEWS} | |
6938 | @item | |
6939 | @file{gdb/README} | |
6940 | @end itemize | |
6941 | ||
0816590b | 6942 | @subsubheading Tag the release |
8642bc8f AC |
6943 | |
6944 | Something like: | |
6945 | ||
474c8240 | 6946 | @smallexample |
8642bc8f AC |
6947 | $ d=`date -u +%Y-%m-%d` |
6948 | $ echo $d | |
6949 | 2002-01-24 | |
6950 | $ ( cd insight/src/gdb && cvs -f -q update ) | |
0816590b | 6951 | $ ( cd insight/src && cvs -f -q tag gdb_5_2-$d-release ) |
474c8240 | 6952 | @end smallexample |
8642bc8f | 6953 | |
0816590b | 6954 | Insight is used since that contains more of the release than |
b247355e | 6955 | @value{GDBN}. |
0816590b AC |
6956 | |
6957 | @subsubheading Mention the release on the trunk | |
8642bc8f | 6958 | |
0816590b AC |
6959 | Just put something in the @file{ChangeLog} so that the trunk also |
6960 | indicates when the release was made. | |
6961 | ||
6962 | @subsubheading Restart @file{gdb/version.in} | |
8642bc8f AC |
6963 | |
6964 | If @file{gdb/version.in} does not contain an ISO date such as | |
6965 | @kbd{2002-01-24} then the daily @code{cronjob} won't update it. Having | |
6966 | committed all the release changes it can be set to | |
0816590b | 6967 | @file{5.2.0_0000-00-00-cvs} which will restart things (yes the @kbd{_} |
8642bc8f AC |
6968 | is important - it affects the snapshot process). |
6969 | ||
6970 | Don't forget the @file{ChangeLog}. | |
6971 | ||
0816590b | 6972 | @subsubheading Merge into trunk |
8973da3a | 6973 | |
8642bc8f AC |
6974 | The files committed to the branch may also need changes merged into the |
6975 | trunk. | |
8973da3a | 6976 | |
0816590b AC |
6977 | @subsubheading Revise the release schedule |
6978 | ||
6979 | Post a revised release schedule to @email{gdb@@sources.redhat.com, GDB | |
6980 | Discussion List} with an updated announcement. The schedule can be | |
6981 | generated by running: | |
6982 | ||
6983 | @smallexample | |
6984 | $ ~/ss/schedule `date +%s` schedule | |
6985 | @end smallexample | |
6986 | ||
6987 | @noindent | |
6988 | The first parameter is approximate date/time in seconds (from the epoch) | |
6989 | of the most recent release. | |
6990 | ||
6991 | Also update the schedule @code{cronjob}. | |
6992 | ||
8642bc8f | 6993 | @section Post release |
8973da3a | 6994 | |
8642bc8f | 6995 | Remove any @code{OBSOLETE} code. |
8973da3a | 6996 | |
085dd6e6 JM |
6997 | @node Testsuite |
6998 | ||
6999 | @chapter Testsuite | |
56caf160 | 7000 | @cindex test suite |
085dd6e6 | 7001 | |
56caf160 EZ |
7002 | The testsuite is an important component of the @value{GDBN} package. |
7003 | While it is always worthwhile to encourage user testing, in practice | |
7004 | this is rarely sufficient; users typically use only a small subset of | |
7005 | the available commands, and it has proven all too common for a change | |
7006 | to cause a significant regression that went unnoticed for some time. | |
085dd6e6 | 7007 | |
b247355e NR |
7008 | The @value{GDBN} testsuite uses the DejaGNU testing framework. The |
7009 | tests themselves are calls to various @code{Tcl} procs; the framework | |
7010 | runs all the procs and summarizes the passes and fails. | |
085dd6e6 JM |
7011 | |
7012 | @section Using the Testsuite | |
7013 | ||
56caf160 | 7014 | @cindex running the test suite |
25822942 | 7015 | To run the testsuite, simply go to the @value{GDBN} object directory (or to the |
085dd6e6 JM |
7016 | testsuite's objdir) and type @code{make check}. This just sets up some |
7017 | environment variables and invokes DejaGNU's @code{runtest} script. While | |
7018 | the testsuite is running, you'll get mentions of which test file is in use, | |
7019 | and a mention of any unexpected passes or fails. When the testsuite is | |
7020 | finished, you'll get a summary that looks like this: | |
56caf160 | 7021 | |
474c8240 | 7022 | @smallexample |
085dd6e6 JM |
7023 | === gdb Summary === |
7024 | ||
7025 | # of expected passes 6016 | |
7026 | # of unexpected failures 58 | |
7027 | # of unexpected successes 5 | |
7028 | # of expected failures 183 | |
7029 | # of unresolved testcases 3 | |
7030 | # of untested testcases 5 | |
474c8240 | 7031 | @end smallexample |
56caf160 | 7032 | |
a9f158ec JB |
7033 | To run a specific test script, type: |
7034 | @example | |
7035 | make check RUNTESTFLAGS='@var{tests}' | |
7036 | @end example | |
7037 | where @var{tests} is a list of test script file names, separated by | |
7038 | spaces. | |
7039 | ||
085dd6e6 JM |
7040 | The ideal test run consists of expected passes only; however, reality |
7041 | conspires to keep us from this ideal. Unexpected failures indicate | |
56caf160 EZ |
7042 | real problems, whether in @value{GDBN} or in the testsuite. Expected |
7043 | failures are still failures, but ones which have been decided are too | |
7044 | hard to deal with at the time; for instance, a test case might work | |
7045 | everywhere except on AIX, and there is no prospect of the AIX case | |
7046 | being fixed in the near future. Expected failures should not be added | |
7047 | lightly, since you may be masking serious bugs in @value{GDBN}. | |
7048 | Unexpected successes are expected fails that are passing for some | |
7049 | reason, while unresolved and untested cases often indicate some minor | |
7050 | catastrophe, such as the compiler being unable to deal with a test | |
7051 | program. | |
7052 | ||
7053 | When making any significant change to @value{GDBN}, you should run the | |
7054 | testsuite before and after the change, to confirm that there are no | |
7055 | regressions. Note that truly complete testing would require that you | |
7056 | run the testsuite with all supported configurations and a variety of | |
7057 | compilers; however this is more than really necessary. In many cases | |
7058 | testing with a single configuration is sufficient. Other useful | |
7059 | options are to test one big-endian (Sparc) and one little-endian (x86) | |
7060 | host, a cross config with a builtin simulator (powerpc-eabi, | |
7061 | mips-elf), or a 64-bit host (Alpha). | |
7062 | ||
7063 | If you add new functionality to @value{GDBN}, please consider adding | |
7064 | tests for it as well; this way future @value{GDBN} hackers can detect | |
7065 | and fix their changes that break the functionality you added. | |
7066 | Similarly, if you fix a bug that was not previously reported as a test | |
7067 | failure, please add a test case for it. Some cases are extremely | |
7068 | difficult to test, such as code that handles host OS failures or bugs | |
7069 | in particular versions of compilers, and it's OK not to try to write | |
7070 | tests for all of those. | |
085dd6e6 | 7071 | |
e7dc800a MC |
7072 | DejaGNU supports separate build, host, and target machines. However, |
7073 | some @value{GDBN} test scripts do not work if the build machine and | |
7074 | the host machine are not the same. In such an environment, these scripts | |
7075 | will give a result of ``UNRESOLVED'', like this: | |
7076 | ||
7077 | @smallexample | |
7078 | UNRESOLVED: gdb.base/example.exp: This test script does not work on a remote host. | |
7079 | @end smallexample | |
7080 | ||
085dd6e6 JM |
7081 | @section Testsuite Organization |
7082 | ||
56caf160 | 7083 | @cindex test suite organization |
085dd6e6 JM |
7084 | The testsuite is entirely contained in @file{gdb/testsuite}. While the |
7085 | testsuite includes some makefiles and configury, these are very minimal, | |
7086 | and used for little besides cleaning up, since the tests themselves | |
25822942 | 7087 | handle the compilation of the programs that @value{GDBN} will run. The file |
085dd6e6 | 7088 | @file{testsuite/lib/gdb.exp} contains common utility procs useful for |
25822942 | 7089 | all @value{GDBN} tests, while the directory @file{testsuite/config} contains |
085dd6e6 JM |
7090 | configuration-specific files, typically used for special-purpose |
7091 | definitions of procs like @code{gdb_load} and @code{gdb_start}. | |
7092 | ||
7093 | The tests themselves are to be found in @file{testsuite/gdb.*} and | |
7094 | subdirectories of those. The names of the test files must always end | |
7095 | with @file{.exp}. DejaGNU collects the test files by wildcarding | |
7096 | in the test directories, so both subdirectories and individual files | |
7097 | get chosen and run in alphabetical order. | |
7098 | ||
7099 | The following table lists the main types of subdirectories and what they | |
7100 | are for. Since DejaGNU finds test files no matter where they are | |
7101 | located, and since each test file sets up its own compilation and | |
7102 | execution environment, this organization is simply for convenience and | |
7103 | intelligibility. | |
7104 | ||
56caf160 | 7105 | @table @file |
085dd6e6 | 7106 | @item gdb.base |
085dd6e6 | 7107 | This is the base testsuite. The tests in it should apply to all |
25822942 | 7108 | configurations of @value{GDBN} (but generic native-only tests may live here). |
085dd6e6 | 7109 | The test programs should be in the subset of C that is valid K&R, |
49efadf5 | 7110 | ANSI/ISO, and C@t{++} (@code{#ifdef}s are allowed if necessary, for instance |
085dd6e6 JM |
7111 | for prototypes). |
7112 | ||
7113 | @item gdb.@var{lang} | |
56caf160 | 7114 | Language-specific tests for any language @var{lang} besides C. Examples are |
af6cf26d | 7115 | @file{gdb.cp} and @file{gdb.java}. |
085dd6e6 JM |
7116 | |
7117 | @item gdb.@var{platform} | |
085dd6e6 JM |
7118 | Non-portable tests. The tests are specific to a specific configuration |
7119 | (host or target), such as HP-UX or eCos. Example is @file{gdb.hp}, for | |
7120 | HP-UX. | |
7121 | ||
7122 | @item gdb.@var{compiler} | |
085dd6e6 JM |
7123 | Tests specific to a particular compiler. As of this writing (June |
7124 | 1999), there aren't currently any groups of tests in this category that | |
7125 | couldn't just as sensibly be made platform-specific, but one could | |
56caf160 EZ |
7126 | imagine a @file{gdb.gcc}, for tests of @value{GDBN}'s handling of GCC |
7127 | extensions. | |
085dd6e6 JM |
7128 | |
7129 | @item gdb.@var{subsystem} | |
25822942 | 7130 | Tests that exercise a specific @value{GDBN} subsystem in more depth. For |
085dd6e6 JM |
7131 | instance, @file{gdb.disasm} exercises various disassemblers, while |
7132 | @file{gdb.stabs} tests pathways through the stabs symbol reader. | |
085dd6e6 JM |
7133 | @end table |
7134 | ||
7135 | @section Writing Tests | |
56caf160 | 7136 | @cindex writing tests |
085dd6e6 | 7137 | |
25822942 | 7138 | In many areas, the @value{GDBN} tests are already quite comprehensive; you |
085dd6e6 JM |
7139 | should be able to copy existing tests to handle new cases. |
7140 | ||
7141 | You should try to use @code{gdb_test} whenever possible, since it | |
7142 | includes cases to handle all the unexpected errors that might happen. | |
7143 | However, it doesn't cost anything to add new test procedures; for | |
7144 | instance, @file{gdb.base/exprs.exp} defines a @code{test_expr} that | |
7145 | calls @code{gdb_test} multiple times. | |
7146 | ||
7147 | Only use @code{send_gdb} and @code{gdb_expect} when absolutely | |
8a3dae3e DJ |
7148 | necessary. Even if @value{GDBN} has several valid responses to |
7149 | a command, you can use @code{gdb_test_multiple}. Like @code{gdb_test}, | |
7150 | @code{gdb_test_multiple} recognizes internal errors and unexpected | |
7151 | prompts. | |
7152 | ||
7153 | Do not write tests which expect a literal tab character from @value{GDBN}. | |
7154 | On some operating systems (e.g.@: OpenBSD) the TTY layer expands tabs to | |
7155 | spaces, so by the time @value{GDBN}'s output reaches expect the tab is gone. | |
085dd6e6 JM |
7156 | |
7157 | The source language programs do @emph{not} need to be in a consistent | |
25822942 | 7158 | style. Since @value{GDBN} is used to debug programs written in many different |
085dd6e6 | 7159 | styles, it's worth having a mix of styles in the testsuite; for |
25822942 | 7160 | instance, some @value{GDBN} bugs involving the display of source lines would |
085dd6e6 JM |
7161 | never manifest themselves if the programs used GNU coding style |
7162 | uniformly. | |
7163 | ||
c906108c SS |
7164 | @node Hints |
7165 | ||
7166 | @chapter Hints | |
7167 | ||
7168 | Check the @file{README} file, it often has useful information that does not | |
7169 | appear anywhere else in the directory. | |
7170 | ||
7171 | @menu | |
25822942 | 7172 | * Getting Started:: Getting started working on @value{GDBN} |
33e16fad | 7173 | * Debugging GDB:: Debugging @value{GDBN} with itself |
c906108c SS |
7174 | @end menu |
7175 | ||
7176 | @node Getting Started,,, Hints | |
7177 | ||
7178 | @section Getting Started | |
7179 | ||
25822942 | 7180 | @value{GDBN} is a large and complicated program, and if you first starting to |
c906108c SS |
7181 | work on it, it can be hard to know where to start. Fortunately, if you |
7182 | know how to go about it, there are ways to figure out what is going on. | |
7183 | ||
25822942 DB |
7184 | This manual, the @value{GDBN} Internals manual, has information which applies |
7185 | generally to many parts of @value{GDBN}. | |
c906108c SS |
7186 | |
7187 | Information about particular functions or data structures are located in | |
7188 | comments with those functions or data structures. If you run across a | |
7189 | function or a global variable which does not have a comment correctly | |
25822942 | 7190 | explaining what is does, this can be thought of as a bug in @value{GDBN}; feel |
c906108c SS |
7191 | free to submit a bug report, with a suggested comment if you can figure |
7192 | out what the comment should say. If you find a comment which is | |
7193 | actually wrong, be especially sure to report that. | |
7194 | ||
7195 | Comments explaining the function of macros defined in host, target, or | |
7196 | native dependent files can be in several places. Sometimes they are | |
7197 | repeated every place the macro is defined. Sometimes they are where the | |
7198 | macro is used. Sometimes there is a header file which supplies a | |
7199 | default definition of the macro, and the comment is there. This manual | |
7200 | also documents all the available macros. | |
7201 | @c (@pxref{Host Conditionals}, @pxref{Target | |
7202 | @c Conditionals}, @pxref{Native Conditionals}, and @pxref{Obsolete | |
7203 | @c Conditionals}) | |
7204 | ||
56caf160 EZ |
7205 | Start with the header files. Once you have some idea of how |
7206 | @value{GDBN}'s internal symbol tables are stored (see @file{symtab.h}, | |
7207 | @file{gdbtypes.h}), you will find it much easier to understand the | |
7208 | code which uses and creates those symbol tables. | |
c906108c SS |
7209 | |
7210 | You may wish to process the information you are getting somehow, to | |
7211 | enhance your understanding of it. Summarize it, translate it to another | |
25822942 | 7212 | language, add some (perhaps trivial or non-useful) feature to @value{GDBN}, use |
c906108c SS |
7213 | the code to predict what a test case would do and write the test case |
7214 | and verify your prediction, etc. If you are reading code and your eyes | |
7215 | are starting to glaze over, this is a sign you need to use a more active | |
7216 | approach. | |
7217 | ||
25822942 | 7218 | Once you have a part of @value{GDBN} to start with, you can find more |
c906108c SS |
7219 | specifically the part you are looking for by stepping through each |
7220 | function with the @code{next} command. Do not use @code{step} or you | |
7221 | will quickly get distracted; when the function you are stepping through | |
7222 | calls another function try only to get a big-picture understanding | |
7223 | (perhaps using the comment at the beginning of the function being | |
7224 | called) of what it does. This way you can identify which of the | |
7225 | functions being called by the function you are stepping through is the | |
7226 | one which you are interested in. You may need to examine the data | |
7227 | structures generated at each stage, with reference to the comments in | |
7228 | the header files explaining what the data structures are supposed to | |
7229 | look like. | |
7230 | ||
7231 | Of course, this same technique can be used if you are just reading the | |
7232 | code, rather than actually stepping through it. The same general | |
7233 | principle applies---when the code you are looking at calls something | |
7234 | else, just try to understand generally what the code being called does, | |
7235 | rather than worrying about all its details. | |
7236 | ||
56caf160 EZ |
7237 | @cindex command implementation |
7238 | A good place to start when tracking down some particular area is with | |
7239 | a command which invokes that feature. Suppose you want to know how | |
7240 | single-stepping works. As a @value{GDBN} user, you know that the | |
7241 | @code{step} command invokes single-stepping. The command is invoked | |
7242 | via command tables (see @file{command.h}); by convention the function | |
7243 | which actually performs the command is formed by taking the name of | |
7244 | the command and adding @samp{_command}, or in the case of an | |
7245 | @code{info} subcommand, @samp{_info}. For example, the @code{step} | |
7246 | command invokes the @code{step_command} function and the @code{info | |
7247 | display} command invokes @code{display_info}. When this convention is | |
7248 | not followed, you might have to use @code{grep} or @kbd{M-x | |
7249 | tags-search} in emacs, or run @value{GDBN} on itself and set a | |
7250 | breakpoint in @code{execute_command}. | |
7251 | ||
7252 | @cindex @code{bug-gdb} mailing list | |
c906108c SS |
7253 | If all of the above fail, it may be appropriate to ask for information |
7254 | on @code{bug-gdb}. But @emph{never} post a generic question like ``I was | |
7255 | wondering if anyone could give me some tips about understanding | |
25822942 | 7256 | @value{GDBN}''---if we had some magic secret we would put it in this manual. |
c906108c SS |
7257 | Suggestions for improving the manual are always welcome, of course. |
7258 | ||
33e16fad | 7259 | @node Debugging GDB,,,Hints |
c906108c | 7260 | |
25822942 | 7261 | @section Debugging @value{GDBN} with itself |
56caf160 | 7262 | @cindex debugging @value{GDBN} |
c906108c | 7263 | |
25822942 | 7264 | If @value{GDBN} is limping on your machine, this is the preferred way to get it |
c906108c SS |
7265 | fully functional. Be warned that in some ancient Unix systems, like |
7266 | Ultrix 4.2, a program can't be running in one process while it is being | |
56caf160 | 7267 | debugged in another. Rather than typing the command @kbd{@w{./gdb |
c906108c | 7268 | ./gdb}}, which works on Suns and such, you can copy @file{gdb} to |
56caf160 | 7269 | @file{gdb2} and then type @kbd{@w{./gdb ./gdb2}}. |
c906108c | 7270 | |
25822942 | 7271 | When you run @value{GDBN} in the @value{GDBN} source directory, it will read a |
c906108c SS |
7272 | @file{.gdbinit} file that sets up some simple things to make debugging |
7273 | gdb easier. The @code{info} command, when executed without a subcommand | |
25822942 | 7274 | in a @value{GDBN} being debugged by gdb, will pop you back up to the top level |
c906108c SS |
7275 | gdb. See @file{.gdbinit} for details. |
7276 | ||
7277 | If you use emacs, you will probably want to do a @code{make TAGS} after | |
7278 | you configure your distribution; this will put the machine dependent | |
7279 | routines for your local machine where they will be accessed first by | |
7280 | @kbd{M-.} | |
7281 | ||
25822942 | 7282 | Also, make sure that you've either compiled @value{GDBN} with your local cc, or |
c906108c SS |
7283 | have run @code{fixincludes} if you are compiling with gcc. |
7284 | ||
7285 | @section Submitting Patches | |
7286 | ||
56caf160 | 7287 | @cindex submitting patches |
c906108c | 7288 | Thanks for thinking of offering your changes back to the community of |
25822942 | 7289 | @value{GDBN} users. In general we like to get well designed enhancements. |
c906108c SS |
7290 | Thanks also for checking in advance about the best way to transfer the |
7291 | changes. | |
7292 | ||
25822942 DB |
7293 | The @value{GDBN} maintainers will only install ``cleanly designed'' patches. |
7294 | This manual summarizes what we believe to be clean design for @value{GDBN}. | |
c906108c SS |
7295 | |
7296 | If the maintainers don't have time to put the patch in when it arrives, | |
7297 | or if there is any question about a patch, it goes into a large queue | |
7298 | with everyone else's patches and bug reports. | |
7299 | ||
56caf160 | 7300 | @cindex legal papers for code contributions |
c906108c SS |
7301 | The legal issue is that to incorporate substantial changes requires a |
7302 | copyright assignment from you and/or your employer, granting ownership | |
7303 | of the changes to the Free Software Foundation. You can get the | |
9e0b60a8 JM |
7304 | standard documents for doing this by sending mail to @code{gnu@@gnu.org} |
7305 | and asking for it. We recommend that people write in "All programs | |
7306 | owned by the Free Software Foundation" as "NAME OF PROGRAM", so that | |
56caf160 EZ |
7307 | changes in many programs (not just @value{GDBN}, but GAS, Emacs, GCC, |
7308 | etc) can be | |
9e0b60a8 | 7309 | contributed with only one piece of legalese pushed through the |
be9c6c35 | 7310 | bureaucracy and filed with the FSF. We can't start merging changes until |
9e0b60a8 JM |
7311 | this paperwork is received by the FSF (their rules, which we follow |
7312 | since we maintain it for them). | |
c906108c SS |
7313 | |
7314 | Technically, the easiest way to receive changes is to receive each | |
56caf160 EZ |
7315 | feature as a small context diff or unidiff, suitable for @code{patch}. |
7316 | Each message sent to me should include the changes to C code and | |
7317 | header files for a single feature, plus @file{ChangeLog} entries for | |
7318 | each directory where files were modified, and diffs for any changes | |
7319 | needed to the manuals (@file{gdb/doc/gdb.texinfo} or | |
7320 | @file{gdb/doc/gdbint.texinfo}). If there are a lot of changes for a | |
7321 | single feature, they can be split down into multiple messages. | |
9e0b60a8 JM |
7322 | |
7323 | In this way, if we read and like the feature, we can add it to the | |
c906108c | 7324 | sources with a single patch command, do some testing, and check it in. |
56caf160 EZ |
7325 | If you leave out the @file{ChangeLog}, we have to write one. If you leave |
7326 | out the doc, we have to puzzle out what needs documenting. Etc., etc. | |
c906108c | 7327 | |
9e0b60a8 JM |
7328 | The reason to send each change in a separate message is that we will not |
7329 | install some of the changes. They'll be returned to you with questions | |
7330 | or comments. If we're doing our job correctly, the message back to you | |
c906108c | 7331 | will say what you have to fix in order to make the change acceptable. |
9e0b60a8 JM |
7332 | The reason to have separate messages for separate features is so that |
7333 | the acceptable changes can be installed while one or more changes are | |
7334 | being reworked. If multiple features are sent in a single message, we | |
7335 | tend to not put in the effort to sort out the acceptable changes from | |
7336 | the unacceptable, so none of the features get installed until all are | |
7337 | acceptable. | |
7338 | ||
7339 | If this sounds painful or authoritarian, well, it is. But we get a lot | |
7340 | of bug reports and a lot of patches, and many of them don't get | |
7341 | installed because we don't have the time to finish the job that the bug | |
c906108c SS |
7342 | reporter or the contributor could have done. Patches that arrive |
7343 | complete, working, and well designed, tend to get installed on the day | |
9e0b60a8 JM |
7344 | they arrive. The others go into a queue and get installed as time |
7345 | permits, which, since the maintainers have many demands to meet, may not | |
7346 | be for quite some time. | |
c906108c | 7347 | |
56caf160 | 7348 | Please send patches directly to |
47b95330 | 7349 | @email{gdb-patches@@sources.redhat.com, the @value{GDBN} maintainers}. |
c906108c SS |
7350 | |
7351 | @section Obsolete Conditionals | |
56caf160 | 7352 | @cindex obsolete code |
c906108c | 7353 | |
25822942 | 7354 | Fragments of old code in @value{GDBN} sometimes reference or set the following |
c906108c SS |
7355 | configuration macros. They should not be used by new code, and old uses |
7356 | should be removed as those parts of the debugger are otherwise touched. | |
7357 | ||
7358 | @table @code | |
c906108c SS |
7359 | @item STACK_END_ADDR |
7360 | This macro used to define where the end of the stack appeared, for use | |
7361 | in interpreting core file formats that don't record this address in the | |
25822942 DB |
7362 | core file itself. This information is now configured in BFD, and @value{GDBN} |
7363 | gets the info portably from there. The values in @value{GDBN}'s configuration | |
c906108c | 7364 | files should be moved into BFD configuration files (if needed there), |
25822942 | 7365 | and deleted from all of @value{GDBN}'s config files. |
c906108c SS |
7366 | |
7367 | Any @file{@var{foo}-xdep.c} file that references STACK_END_ADDR | |
7368 | is so old that it has never been converted to use BFD. Now that's old! | |
7369 | ||
c906108c SS |
7370 | @end table |
7371 | ||
bcd7e15f | 7372 | @include observer.texi |
2154891a | 7373 | @raisesections |
aab4e0ec | 7374 | @include fdl.texi |
2154891a | 7375 | @lowersections |
aab4e0ec | 7376 | |
56caf160 EZ |
7377 | @node Index |
7378 | @unnumbered Index | |
7379 | ||
7380 | @printindex cp | |
7381 | ||
c906108c | 7382 | @bye |