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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 | 8 | |
a67ec3f4 JM |
9 | @copying |
10 | Copyright @copyright{} 1990, 1991, 1992, 1993, 1994, 1996, 1998, 1999, | |
11 | 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2008, 2009 | |
12 | Free Software Foundation, Inc. | |
c906108c SS |
13 | Contributed by Cygnus Solutions. Written by John Gilmore. |
14 | Second Edition by Stan Shebs. | |
15 | ||
e9c75b65 EZ |
16 | Permission is granted to copy, distribute and/or modify this document |
17 | under the terms of the GNU Free Documentation License, Version 1.1 or | |
2a6585f0 | 18 | any later version published by the Free Software Foundation; with no |
e5249f67 AC |
19 | Invariant Sections, with no Front-Cover Texts, and with no Back-Cover |
20 | Texts. A copy of the license is included in the section entitled ``GNU | |
21 | Free Documentation License''. | |
a67ec3f4 JM |
22 | @end copying |
23 | ||
24 | @ifnottex | |
25 | This file documents the internals of the GNU debugger @value{GDBN}. | |
26 | ||
27 | @insertcopying | |
28 | @end ifnottex | |
c906108c SS |
29 | |
30 | @setchapternewpage off | |
25822942 | 31 | @settitle @value{GDBN} Internals |
c906108c | 32 | |
56caf160 EZ |
33 | @syncodeindex fn cp |
34 | @syncodeindex vr cp | |
35 | ||
c906108c | 36 | @titlepage |
25822942 | 37 | @title @value{GDBN} Internals |
c906108c SS |
38 | @subtitle{A guide to the internals of the GNU debugger} |
39 | @author John Gilmore | |
40 | @author Cygnus Solutions | |
41 | @author Second Edition: | |
42 | @author Stan Shebs | |
43 | @author Cygnus Solutions | |
44 | @page | |
45 | @tex | |
46 | \def\$#1${{#1}} % Kluge: collect RCS revision info without $...$ | |
47 | \xdef\manvers{\$Revision$} % For use in headers, footers too | |
48 | {\parskip=0pt | |
49 | \hfill Cygnus Solutions\par | |
50 | \hfill \manvers\par | |
51 | \hfill \TeX{}info \texinfoversion\par | |
52 | } | |
53 | @end tex | |
54 | ||
55 | @vskip 0pt plus 1filll | |
a67ec3f4 | 56 | @insertcopying |
c906108c SS |
57 | @end titlepage |
58 | ||
449f3b6c | 59 | @contents |
449f3b6c | 60 | |
c906108c SS |
61 | @node Top |
62 | @c Perhaps this should be the title of the document (but only for info, | |
63 | @c not for TeX). Existing GNU manuals seem inconsistent on this point. | |
64 | @top Scope of this Document | |
65 | ||
25822942 DB |
66 | This document documents the internals of the GNU debugger, @value{GDBN}. It |
67 | includes description of @value{GDBN}'s key algorithms and operations, as well | |
68 | as the mechanisms that adapt @value{GDBN} to specific hosts and targets. | |
c906108c SS |
69 | |
70 | @menu | |
71 | * Requirements:: | |
72 | * Overall Structure:: | |
73 | * Algorithms:: | |
74 | * User Interface:: | |
89437448 | 75 | * libgdb:: |
5f5233d4 | 76 | * Values:: |
669fac23 | 77 | * Stack Frames:: |
c906108c SS |
78 | * Symbol Handling:: |
79 | * Language Support:: | |
80 | * Host Definition:: | |
81 | * Target Architecture Definition:: | |
123dc839 | 82 | * Target Descriptions:: |
c906108c SS |
83 | * Target Vector Definition:: |
84 | * Native Debugging:: | |
85 | * Support Libraries:: | |
86 | * Coding:: | |
87 | * Porting GDB:: | |
d52fe014 | 88 | * Versions and Branches:: |
55f6ca0f | 89 | * Start of New Year Procedure:: |
8973da3a | 90 | * Releasing GDB:: |
085dd6e6 | 91 | * Testsuite:: |
c906108c | 92 | * Hints:: |
aab4e0ec | 93 | |
bcd7e15f | 94 | * GDB Observers:: @value{GDBN} Currently available observers |
aab4e0ec | 95 | * GNU Free Documentation License:: The license for this documentation |
56caf160 | 96 | * Index:: |
c906108c SS |
97 | @end menu |
98 | ||
99 | @node Requirements | |
100 | ||
101 | @chapter Requirements | |
56caf160 | 102 | @cindex requirements for @value{GDBN} |
c906108c SS |
103 | |
104 | Before diving into the internals, you should understand the formal | |
56caf160 EZ |
105 | requirements and other expectations for @value{GDBN}. Although some |
106 | of these may seem obvious, there have been proposals for @value{GDBN} | |
107 | that have run counter to these requirements. | |
c906108c | 108 | |
56caf160 EZ |
109 | First of all, @value{GDBN} is a debugger. It's not designed to be a |
110 | front panel for embedded systems. It's not a text editor. It's not a | |
111 | shell. It's not a programming environment. | |
c906108c | 112 | |
56caf160 EZ |
113 | @value{GDBN} is an interactive tool. Although a batch mode is |
114 | available, @value{GDBN}'s primary role is to interact with a human | |
115 | programmer. | |
c906108c | 116 | |
56caf160 EZ |
117 | @value{GDBN} should be responsive to the user. A programmer hot on |
118 | the trail of a nasty bug, and operating under a looming deadline, is | |
119 | going to be very impatient of everything, including the response time | |
120 | to debugger commands. | |
c906108c | 121 | |
56caf160 EZ |
122 | @value{GDBN} should be relatively permissive, such as for expressions. |
123 | While the compiler should be picky (or have the option to be made | |
be9c6c35 | 124 | picky), since source code lives for a long time usually, the |
56caf160 EZ |
125 | programmer doing debugging shouldn't be spending time figuring out to |
126 | mollify the debugger. | |
c906108c | 127 | |
56caf160 EZ |
128 | @value{GDBN} will be called upon to deal with really large programs. |
129 | Executable sizes of 50 to 100 megabytes occur regularly, and we've | |
130 | heard reports of programs approaching 1 gigabyte in size. | |
c906108c | 131 | |
56caf160 EZ |
132 | @value{GDBN} should be able to run everywhere. No other debugger is |
133 | available for even half as many configurations as @value{GDBN} | |
134 | supports. | |
c906108c SS |
135 | |
136 | ||
137 | @node Overall Structure | |
138 | ||
139 | @chapter Overall Structure | |
140 | ||
56caf160 EZ |
141 | @value{GDBN} consists of three major subsystems: user interface, |
142 | symbol handling (the @dfn{symbol side}), and target system handling (the | |
143 | @dfn{target side}). | |
c906108c | 144 | |
2e685b93 | 145 | The user interface consists of several actual interfaces, plus |
c906108c SS |
146 | supporting code. |
147 | ||
148 | The symbol side consists of object file readers, debugging info | |
149 | interpreters, symbol table management, source language expression | |
150 | parsing, type and value printing. | |
151 | ||
152 | The target side consists of execution control, stack frame analysis, and | |
153 | physical target manipulation. | |
154 | ||
155 | The target side/symbol side division is not formal, and there are a | |
156 | number of exceptions. For instance, core file support involves symbolic | |
157 | elements (the basic core file reader is in BFD) and target elements (it | |
158 | supplies the contents of memory and the values of registers). Instead, | |
159 | this division is useful for understanding how the minor subsystems | |
160 | should fit together. | |
161 | ||
162 | @section The Symbol Side | |
163 | ||
56caf160 EZ |
164 | The symbolic side of @value{GDBN} can be thought of as ``everything |
165 | you can do in @value{GDBN} without having a live program running''. | |
166 | For instance, you can look at the types of variables, and evaluate | |
167 | many kinds of expressions. | |
c906108c SS |
168 | |
169 | @section The Target Side | |
170 | ||
56caf160 EZ |
171 | The target side of @value{GDBN} is the ``bits and bytes manipulator''. |
172 | Although it may make reference to symbolic info here and there, most | |
173 | of the target side will run with only a stripped executable | |
174 | available---or even no executable at all, in remote debugging cases. | |
c906108c SS |
175 | |
176 | Operations such as disassembly, stack frame crawls, and register | |
177 | display, are able to work with no symbolic info at all. In some cases, | |
25822942 | 178 | such as disassembly, @value{GDBN} will use symbolic info to present addresses |
c906108c SS |
179 | relative to symbols rather than as raw numbers, but it will work either |
180 | way. | |
181 | ||
182 | @section Configurations | |
183 | ||
56caf160 EZ |
184 | @cindex host |
185 | @cindex target | |
25822942 | 186 | @dfn{Host} refers to attributes of the system where @value{GDBN} runs. |
c906108c SS |
187 | @dfn{Target} refers to the system where the program being debugged |
188 | executes. In most cases they are the same machine, in which case a | |
189 | third type of @dfn{Native} attributes come into play. | |
190 | ||
1f70da6a SS |
191 | Defines and include files needed to build on the host are host |
192 | support. Examples are tty support, system defined types, host byte | |
193 | order, host float format. These are all calculated by @code{autoconf} | |
194 | when the debugger is built. | |
c906108c SS |
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 | |
1f70da6a | 203 | host and target are not the same, calling @code{fork} to start the target |
c906108c SS |
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 | ||
1f70da6a SS |
213 | When you want to make @value{GDBN} work as the traditional native debugger |
214 | on a system, you will need to supply both target and native information. | |
c906108c | 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 | 275 | |
7d30c22d JB |
276 | @section Prologue Analysis |
277 | ||
278 | @cindex prologue analysis | |
279 | @cindex call frame information | |
280 | @cindex CFI (call frame information) | |
281 | To produce a backtrace and allow the user to manipulate older frames' | |
282 | variables and arguments, @value{GDBN} needs to find the base addresses | |
283 | of older frames, and discover where those frames' registers have been | |
284 | saved. Since a frame's ``callee-saves'' registers get saved by | |
285 | younger frames if and when they're reused, a frame's registers may be | |
286 | scattered unpredictably across younger frames. This means that | |
287 | changing the value of a register-allocated variable in an older frame | |
288 | may actually entail writing to a save slot in some younger frame. | |
289 | ||
290 | Modern versions of GCC emit Dwarf call frame information (``CFI''), | |
291 | which describes how to find frame base addresses and saved registers. | |
292 | But CFI is not always available, so as a fallback @value{GDBN} uses a | |
293 | technique called @dfn{prologue analysis} to find frame sizes and saved | |
294 | registers. A prologue analyzer disassembles the function's machine | |
295 | code starting from its entry point, and looks for instructions that | |
296 | allocate frame space, save the stack pointer in a frame pointer | |
297 | register, save registers, and so on. Obviously, this can't be done | |
b247355e | 298 | accurately in general, but it's tractable to do well enough to be very |
7d30c22d JB |
299 | helpful. Prologue analysis predates the GNU toolchain's support for |
300 | CFI; at one time, prologue analysis was the only mechanism | |
301 | @value{GDBN} used for stack unwinding at all, when the function | |
302 | calling conventions didn't specify a fixed frame layout. | |
303 | ||
304 | In the olden days, function prologues were generated by hand-written, | |
305 | target-specific code in GCC, and treated as opaque and untouchable by | |
306 | optimizers. Looking at this code, it was usually straightforward to | |
307 | write a prologue analyzer for @value{GDBN} that would accurately | |
308 | understand all the prologues GCC would generate. However, over time | |
309 | GCC became more aggressive about instruction scheduling, and began to | |
310 | understand more about the semantics of the prologue instructions | |
311 | themselves; in response, @value{GDBN}'s analyzers became more complex | |
312 | and fragile. Keeping the prologue analyzers working as GCC (and the | |
313 | instruction sets themselves) evolved became a substantial task. | |
314 | ||
315 | @cindex @file{prologue-value.c} | |
316 | @cindex abstract interpretation of function prologues | |
317 | @cindex pseudo-evaluation of function prologues | |
318 | To try to address this problem, the code in @file{prologue-value.h} | |
319 | and @file{prologue-value.c} provides a general framework for writing | |
320 | prologue analyzers that are simpler and more robust than ad-hoc | |
321 | analyzers. When we analyze a prologue using the prologue-value | |
322 | framework, we're really doing ``abstract interpretation'' or | |
323 | ``pseudo-evaluation'': running the function's code in simulation, but | |
324 | using conservative approximations of the values registers and memory | |
325 | would hold when the code actually runs. For example, if our function | |
326 | starts with the instruction: | |
327 | ||
328 | @example | |
329 | addi r1, 42 # add 42 to r1 | |
330 | @end example | |
331 | @noindent | |
332 | we don't know exactly what value will be in @code{r1} after executing | |
333 | this instruction, but we do know it'll be 42 greater than its original | |
334 | value. | |
335 | ||
336 | If we then see an instruction like: | |
337 | ||
338 | @example | |
339 | addi r1, 22 # add 22 to r1 | |
340 | @end example | |
341 | @noindent | |
342 | we still don't know what @code{r1's} value is, but again, we can say | |
343 | it is now 64 greater than its original value. | |
344 | ||
345 | If the next instruction were: | |
346 | ||
347 | @example | |
348 | mov r2, r1 # set r2 to r1's value | |
349 | @end example | |
350 | @noindent | |
351 | then we can say that @code{r2's} value is now the original value of | |
352 | @code{r1} plus 64. | |
353 | ||
354 | It's common for prologues to save registers on the stack, so we'll | |
355 | need to track the values of stack frame slots, as well as the | |
356 | registers. So after an instruction like this: | |
357 | ||
358 | @example | |
359 | mov (fp+4), r2 | |
360 | @end example | |
361 | @noindent | |
362 | then we'd know that the stack slot four bytes above the frame pointer | |
363 | holds the original value of @code{r1} plus 64. | |
364 | ||
365 | And so on. | |
366 | ||
367 | Of course, this can only go so far before it gets unreasonable. If we | |
368 | wanted to be able to say anything about the value of @code{r1} after | |
369 | the instruction: | |
370 | ||
371 | @example | |
372 | xor r1, r3 # exclusive-or r1 and r3, place result in r1 | |
373 | @end example | |
374 | @noindent | |
375 | then things would get pretty complex. But remember, we're just doing | |
376 | a conservative approximation; if exclusive-or instructions aren't | |
377 | relevant to prologues, we can just say @code{r1}'s value is now | |
378 | ``unknown''. We can ignore things that are too complex, if that loss of | |
379 | information is acceptable for our application. | |
380 | ||
381 | So when we say ``conservative approximation'' here, what we mean is an | |
382 | approximation that is either accurate, or marked ``unknown'', but | |
383 | never inaccurate. | |
384 | ||
385 | Using this framework, a prologue analyzer is simply an interpreter for | |
386 | machine code, but one that uses conservative approximations for the | |
387 | contents of registers and memory instead of actual values. Starting | |
388 | from the function's entry point, you simulate instructions up to the | |
389 | current PC, or an instruction that you don't know how to simulate. | |
390 | Now you can examine the state of the registers and stack slots you've | |
391 | kept track of. | |
392 | ||
393 | @itemize @bullet | |
394 | ||
395 | @item | |
396 | To see how large your stack frame is, just check the value of the | |
397 | stack pointer register; if it's the original value of the SP | |
398 | minus a constant, then that constant is the stack frame's size. | |
399 | If the SP's value has been marked as ``unknown'', then that means | |
400 | the prologue has done something too complex for us to track, and | |
401 | we don't know the frame size. | |
402 | ||
403 | @item | |
404 | To see where we've saved the previous frame's registers, we just | |
405 | search the values we've tracked --- stack slots, usually, but | |
406 | registers, too, if you want --- for something equal to the register's | |
407 | original value. If the calling conventions suggest a standard place | |
408 | to save a given register, then we can check there first, but really, | |
409 | anything that will get us back the original value will probably work. | |
410 | @end itemize | |
411 | ||
412 | This does take some work. But prologue analyzers aren't | |
413 | quick-and-simple pattern patching to recognize a few fixed prologue | |
414 | forms any more; they're big, hairy functions. Along with inferior | |
415 | function calls, prologue analysis accounts for a substantial portion | |
416 | of the time needed to stabilize a @value{GDBN} port. So it's | |
417 | worthwhile to look for an approach that will be easier to understand | |
418 | and maintain. In the approach described above: | |
419 | ||
420 | @itemize @bullet | |
421 | ||
422 | @item | |
423 | It's easier to see that the analyzer is correct: you just see | |
b247355e | 424 | whether the analyzer properly (albeit conservatively) simulates |
7d30c22d JB |
425 | the effect of each instruction. |
426 | ||
427 | @item | |
428 | It's easier to extend the analyzer: you can add support for new | |
429 | instructions, and know that you haven't broken anything that | |
430 | wasn't already broken before. | |
431 | ||
432 | @item | |
433 | It's orthogonal: to gather new information, you don't need to | |
434 | complicate the code for each instruction. As long as your domain | |
435 | of conservative values is already detailed enough to tell you | |
436 | what you need, then all the existing instruction simulations are | |
437 | already gathering the right data for you. | |
438 | ||
439 | @end itemize | |
440 | ||
441 | The file @file{prologue-value.h} contains detailed comments explaining | |
442 | the framework and how to use it. | |
443 | ||
444 | ||
c906108c SS |
445 | @section Breakpoint Handling |
446 | ||
56caf160 | 447 | @cindex breakpoints |
c906108c SS |
448 | In general, a breakpoint is a user-designated location in the program |
449 | where the user wants to regain control if program execution ever reaches | |
450 | that location. | |
451 | ||
452 | There are two main ways to implement breakpoints; either as ``hardware'' | |
453 | breakpoints or as ``software'' breakpoints. | |
454 | ||
56caf160 EZ |
455 | @cindex hardware breakpoints |
456 | @cindex program counter | |
c906108c SS |
457 | Hardware breakpoints are sometimes available as a builtin debugging |
458 | features with some chips. Typically these work by having dedicated | |
459 | register into which the breakpoint address may be stored. If the PC | |
56caf160 | 460 | (shorthand for @dfn{program counter}) |
c906108c | 461 | ever matches a value in a breakpoint registers, the CPU raises an |
56caf160 EZ |
462 | exception and reports it to @value{GDBN}. |
463 | ||
464 | Another possibility is when an emulator is in use; many emulators | |
465 | include circuitry that watches the address lines coming out from the | |
466 | processor, and force it to stop if the address matches a breakpoint's | |
467 | address. | |
468 | ||
469 | A third possibility is that the target already has the ability to do | |
470 | breakpoints somehow; for instance, a ROM monitor may do its own | |
471 | software breakpoints. So although these are not literally ``hardware | |
472 | breakpoints'', from @value{GDBN}'s point of view they work the same; | |
50e3ee83 | 473 | @value{GDBN} need not do anything more than set the breakpoint and wait |
56caf160 | 474 | for something to happen. |
c906108c SS |
475 | |
476 | Since they depend on hardware resources, hardware breakpoints may be | |
56caf160 | 477 | limited in number; when the user asks for more, @value{GDBN} will |
9742079a | 478 | start trying to set software breakpoints. (On some architectures, |
937f164b | 479 | notably the 32-bit x86 platforms, @value{GDBN} cannot always know |
9742079a EZ |
480 | whether there's enough hardware resources to insert all the hardware |
481 | breakpoints and watchpoints. On those platforms, @value{GDBN} prints | |
482 | an error message only when the program being debugged is continued.) | |
56caf160 EZ |
483 | |
484 | @cindex software breakpoints | |
485 | Software breakpoints require @value{GDBN} to do somewhat more work. | |
486 | The basic theory is that @value{GDBN} will replace a program | |
487 | instruction with a trap, illegal divide, or some other instruction | |
488 | that will cause an exception, and then when it's encountered, | |
489 | @value{GDBN} will take the exception and stop the program. When the | |
490 | user says to continue, @value{GDBN} will restore the original | |
c906108c SS |
491 | instruction, single-step, re-insert the trap, and continue on. |
492 | ||
493 | Since it literally overwrites the program being tested, the program area | |
be9c6c35 | 494 | must be writable, so this technique won't work on programs in ROM. It |
c906108c | 495 | can also distort the behavior of programs that examine themselves, |
56caf160 | 496 | although such a situation would be highly unusual. |
c906108c SS |
497 | |
498 | Also, the software breakpoint instruction should be the smallest size of | |
499 | instruction, so it doesn't overwrite an instruction that might be a jump | |
500 | target, and cause disaster when the program jumps into the middle of the | |
501 | breakpoint instruction. (Strictly speaking, the breakpoint must be no | |
502 | larger than the smallest interval between instructions that may be jump | |
503 | targets; perhaps there is an architecture where only even-numbered | |
504 | instructions may jumped to.) Note that it's possible for an instruction | |
505 | set not to have any instructions usable for a software breakpoint, | |
506 | although in practice only the ARC has failed to define such an | |
507 | instruction. | |
508 | ||
c906108c SS |
509 | Basic breakpoint object handling is in @file{breakpoint.c}. However, |
510 | much of the interesting breakpoint action is in @file{infrun.c}. | |
511 | ||
8181d85f DJ |
512 | @table @code |
513 | @cindex insert or remove software breakpoint | |
514 | @findex target_remove_breakpoint | |
515 | @findex target_insert_breakpoint | |
516 | @item target_remove_breakpoint (@var{bp_tgt}) | |
517 | @itemx target_insert_breakpoint (@var{bp_tgt}) | |
518 | Insert or remove a software breakpoint at address | |
519 | @code{@var{bp_tgt}->placed_address}. Returns zero for success, | |
520 | non-zero for failure. On input, @var{bp_tgt} contains the address of the | |
521 | breakpoint, and is otherwise initialized to zero. The fields of the | |
522 | @code{struct bp_target_info} pointed to by @var{bp_tgt} are updated | |
523 | to contain other information about the breakpoint on output. The field | |
524 | @code{placed_address} may be updated if the breakpoint was placed at a | |
525 | related address; the field @code{shadow_contents} contains the real | |
526 | contents of the bytes where the breakpoint has been inserted, | |
527 | if reading memory would return the breakpoint instead of the | |
528 | underlying memory; the field @code{shadow_len} is the length of | |
529 | memory cached in @code{shadow_contents}, if any; and the field | |
530 | @code{placed_size} is optionally set and used by the target, if | |
531 | it could differ from @code{shadow_len}. | |
532 | ||
533 | For example, the remote target @samp{Z0} packet does not require | |
534 | shadowing memory, so @code{shadow_len} is left at zero. However, | |
4a9bb1df | 535 | the length reported by @code{gdbarch_breakpoint_from_pc} is cached in |
8181d85f DJ |
536 | @code{placed_size}, so that a matching @samp{z0} packet can be |
537 | used to remove the breakpoint. | |
538 | ||
539 | @cindex insert or remove hardware breakpoint | |
540 | @findex target_remove_hw_breakpoint | |
541 | @findex target_insert_hw_breakpoint | |
542 | @item target_remove_hw_breakpoint (@var{bp_tgt}) | |
543 | @itemx target_insert_hw_breakpoint (@var{bp_tgt}) | |
544 | Insert or remove a hardware-assisted breakpoint at address | |
545 | @code{@var{bp_tgt}->placed_address}. Returns zero for success, | |
546 | non-zero for failure. See @code{target_insert_breakpoint} for | |
547 | a description of the @code{struct bp_target_info} pointed to by | |
548 | @var{bp_tgt}; the @code{shadow_contents} and | |
549 | @code{shadow_len} members are not used for hardware breakpoints, | |
550 | but @code{placed_size} may be. | |
551 | @end table | |
552 | ||
c906108c SS |
553 | @section Single Stepping |
554 | ||
555 | @section Signal Handling | |
556 | ||
557 | @section Thread Handling | |
558 | ||
559 | @section Inferior Function Calls | |
560 | ||
561 | @section Longjmp Support | |
562 | ||
56caf160 | 563 | @cindex @code{longjmp} debugging |
25822942 | 564 | @value{GDBN} has support for figuring out that the target is doing a |
c906108c SS |
565 | @code{longjmp} and for stopping at the target of the jump, if we are |
566 | stepping. This is done with a few specialized internal breakpoints, | |
56caf160 EZ |
567 | which are visible in the output of the @samp{maint info breakpoint} |
568 | command. | |
c906108c | 569 | |
4a9bb1df UW |
570 | @findex gdbarch_get_longjmp_target |
571 | To make this work, you need to define a function called | |
1f70da6a SS |
572 | @code{gdbarch_get_longjmp_target}, which will examine the |
573 | @code{jmp_buf} structure and extract the @code{longjmp} target address. | |
574 | Since @code{jmp_buf} is target specific and typically defined in a | |
575 | target header not available to @value{GDBN}, you will need to | |
576 | determine the offset of the PC manually and return that; many targets | |
577 | define a @code{jb_pc_offset} field in the tdep structure to save the | |
578 | value once calculated. | |
c906108c | 579 | |
9742079a EZ |
580 | @section Watchpoints |
581 | @cindex watchpoints | |
582 | ||
583 | Watchpoints are a special kind of breakpoints (@pxref{Algorithms, | |
584 | breakpoints}) which break when data is accessed rather than when some | |
585 | instruction is executed. When you have data which changes without | |
586 | your knowing what code does that, watchpoints are the silver bullet to | |
587 | hunt down and kill such bugs. | |
588 | ||
589 | @cindex hardware watchpoints | |
590 | @cindex software watchpoints | |
591 | Watchpoints can be either hardware-assisted or not; the latter type is | |
592 | known as ``software watchpoints.'' @value{GDBN} always uses | |
593 | hardware-assisted watchpoints if they are available, and falls back on | |
594 | software watchpoints otherwise. Typical situations where @value{GDBN} | |
595 | will use software watchpoints are: | |
596 | ||
597 | @itemize @bullet | |
598 | @item | |
599 | The watched memory region is too large for the underlying hardware | |
600 | watchpoint support. For example, each x86 debug register can watch up | |
601 | to 4 bytes of memory, so trying to watch data structures whose size is | |
602 | more than 16 bytes will cause @value{GDBN} to use software | |
603 | watchpoints. | |
604 | ||
605 | @item | |
606 | The value of the expression to be watched depends on data held in | |
607 | registers (as opposed to memory). | |
608 | ||
609 | @item | |
610 | Too many different watchpoints requested. (On some architectures, | |
611 | this situation is impossible to detect until the debugged program is | |
612 | resumed.) Note that x86 debug registers are used both for hardware | |
613 | breakpoints and for watchpoints, so setting too many hardware | |
614 | breakpoints might cause watchpoint insertion to fail. | |
615 | ||
616 | @item | |
617 | No hardware-assisted watchpoints provided by the target | |
618 | implementation. | |
619 | @end itemize | |
620 | ||
621 | Software watchpoints are very slow, since @value{GDBN} needs to | |
622 | single-step the program being debugged and test the value of the | |
623 | watched expression(s) after each instruction. The rest of this | |
624 | section is mostly irrelevant for software watchpoints. | |
625 | ||
b6b8ece6 EZ |
626 | When the inferior stops, @value{GDBN} tries to establish, among other |
627 | possible reasons, whether it stopped due to a watchpoint being hit. | |
d983da9c DJ |
628 | It first uses @code{STOPPED_BY_WATCHPOINT} to see if any watchpoint |
629 | was hit. If not, all watchpoint checking is skipped. | |
630 | ||
631 | Then @value{GDBN} calls @code{target_stopped_data_address} exactly | |
632 | once. This method returns the address of the watchpoint which | |
633 | triggered, if the target can determine it. If the triggered address | |
634 | is available, @value{GDBN} compares the address returned by this | |
635 | method with each watched memory address in each active watchpoint. | |
636 | For data-read and data-access watchpoints, @value{GDBN} announces | |
637 | every watchpoint that watches the triggered address as being hit. | |
638 | For this reason, data-read and data-access watchpoints | |
639 | @emph{require} that the triggered address be available; if not, read | |
640 | and access watchpoints will never be considered hit. For data-write | |
641 | watchpoints, if the triggered address is available, @value{GDBN} | |
642 | considers only those watchpoints which match that address; | |
643 | otherwise, @value{GDBN} considers all data-write watchpoints. For | |
644 | each data-write watchpoint that @value{GDBN} considers, it evaluates | |
645 | the expression whose value is being watched, and tests whether the | |
646 | watched value has changed. Watchpoints whose watched values have | |
647 | changed are announced as hit. | |
b6b8ece6 | 648 | |
1f70da6a SS |
649 | @c FIXME move these to the main lists of target/native defns |
650 | ||
9742079a EZ |
651 | @value{GDBN} uses several macros and primitives to support hardware |
652 | watchpoints: | |
653 | ||
654 | @table @code | |
655 | @findex TARGET_HAS_HARDWARE_WATCHPOINTS | |
656 | @item TARGET_HAS_HARDWARE_WATCHPOINTS | |
657 | If defined, the target supports hardware watchpoints. | |
1f70da6a | 658 | (Currently only used for several native configs.) |
9742079a EZ |
659 | |
660 | @findex TARGET_CAN_USE_HARDWARE_WATCHPOINT | |
661 | @item TARGET_CAN_USE_HARDWARE_WATCHPOINT (@var{type}, @var{count}, @var{other}) | |
662 | Return the number of hardware watchpoints of type @var{type} that are | |
663 | possible to be set. The value is positive if @var{count} watchpoints | |
664 | of this type can be set, zero if setting watchpoints of this type is | |
665 | not supported, and negative if @var{count} is more than the maximum | |
666 | number of watchpoints of type @var{type} that can be set. @var{other} | |
667 | is non-zero if other types of watchpoints are currently enabled (there | |
668 | are architectures which cannot set watchpoints of different types at | |
669 | the same time). | |
670 | ||
671 | @findex TARGET_REGION_OK_FOR_HW_WATCHPOINT | |
672 | @item TARGET_REGION_OK_FOR_HW_WATCHPOINT (@var{addr}, @var{len}) | |
673 | Return non-zero if hardware watchpoints can be used to watch a region | |
674 | whose address is @var{addr} and whose length in bytes is @var{len}. | |
675 | ||
b6b8ece6 | 676 | @cindex insert or remove hardware watchpoint |
9742079a EZ |
677 | @findex target_insert_watchpoint |
678 | @findex target_remove_watchpoint | |
679 | @item target_insert_watchpoint (@var{addr}, @var{len}, @var{type}) | |
680 | @itemx target_remove_watchpoint (@var{addr}, @var{len}, @var{type}) | |
681 | Insert or remove a hardware watchpoint starting at @var{addr}, for | |
682 | @var{len} bytes. @var{type} is the watchpoint type, one of the | |
683 | possible values of the enumerated data type @code{target_hw_bp_type}, | |
684 | defined by @file{breakpoint.h} as follows: | |
685 | ||
474c8240 | 686 | @smallexample |
9742079a EZ |
687 | enum target_hw_bp_type |
688 | @{ | |
689 | hw_write = 0, /* Common (write) HW watchpoint */ | |
690 | hw_read = 1, /* Read HW watchpoint */ | |
691 | hw_access = 2, /* Access (read or write) HW watchpoint */ | |
692 | hw_execute = 3 /* Execute HW breakpoint */ | |
693 | @}; | |
474c8240 | 694 | @end smallexample |
9742079a EZ |
695 | |
696 | @noindent | |
697 | These two macros should return 0 for success, non-zero for failure. | |
698 | ||
9742079a | 699 | @findex target_stopped_data_address |
ac77d04f JJ |
700 | @item target_stopped_data_address (@var{addr_p}) |
701 | If the inferior has some watchpoint that triggered, place the address | |
702 | associated with the watchpoint at the location pointed to by | |
d983da9c DJ |
703 | @var{addr_p} and return non-zero. Otherwise, return zero. This |
704 | is required for data-read and data-access watchpoints. It is | |
705 | not required for data-write watchpoints, but @value{GDBN} uses | |
706 | it to improve handling of those also. | |
707 | ||
708 | @value{GDBN} will only call this method once per watchpoint stop, | |
709 | immediately after calling @code{STOPPED_BY_WATCHPOINT}. If the | |
710 | target's watchpoint indication is sticky, i.e., stays set after | |
711 | resuming, this method should clear it. For instance, the x86 debug | |
712 | control register has sticky triggered flags. | |
9742079a | 713 | |
5009afc5 AS |
714 | @findex target_watchpoint_addr_within_range |
715 | @item target_watchpoint_addr_within_range (@var{target}, @var{addr}, @var{start}, @var{length}) | |
716 | Check whether @var{addr} (as returned by @code{target_stopped_data_address}) | |
717 | lies within the hardware-defined watchpoint region described by | |
718 | @var{start} and @var{length}. This only needs to be provided if the | |
719 | granularity of a watchpoint is greater than one byte, i.e., if the | |
720 | watchpoint can also trigger on nearby addresses outside of the watched | |
721 | region. | |
722 | ||
9742079a EZ |
723 | @findex HAVE_STEPPABLE_WATCHPOINT |
724 | @item HAVE_STEPPABLE_WATCHPOINT | |
725 | If defined to a non-zero value, it is not necessary to disable a | |
5009afc5 | 726 | watchpoint to step over it. Like @code{gdbarch_have_nonsteppable_watchpoint}, |
d983da9c DJ |
727 | this is usually set when watchpoints trigger at the instruction |
728 | which will perform an interesting read or write. It should be | |
729 | set if there is a temporary disable bit which allows the processor | |
730 | to step over the interesting instruction without raising the | |
731 | watchpoint exception again. | |
9742079a | 732 | |
4a9bb1df UW |
733 | @findex gdbarch_have_nonsteppable_watchpoint |
734 | @item int gdbarch_have_nonsteppable_watchpoint (@var{gdbarch}) | |
735 | If it returns a non-zero value, @value{GDBN} should disable a | |
d983da9c DJ |
736 | watchpoint to step the inferior over it. This is usually set when |
737 | watchpoints trigger at the instruction which will perform an | |
738 | interesting read or write. | |
9742079a EZ |
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 | |
d983da9c DJ |
743 | inferior after a watchpoint has been hit. This is usually set |
744 | when watchpoints trigger at the instruction following an interesting | |
745 | read or write. | |
9742079a EZ |
746 | |
747 | @findex CANNOT_STEP_HW_WATCHPOINTS | |
748 | @item CANNOT_STEP_HW_WATCHPOINTS | |
749 | If this is defined to a non-zero value, @value{GDBN} will remove all | |
750 | watchpoints before stepping the inferior. | |
751 | ||
752 | @findex STOPPED_BY_WATCHPOINT | |
753 | @item STOPPED_BY_WATCHPOINT (@var{wait_status}) | |
754 | Return non-zero if stopped by a watchpoint. @var{wait_status} is of | |
755 | the type @code{struct target_waitstatus}, defined by @file{target.h}. | |
b6b8ece6 EZ |
756 | Normally, this macro is defined to invoke the function pointed to by |
757 | the @code{to_stopped_by_watchpoint} member of the structure (of the | |
758 | type @code{target_ops}, defined on @file{target.h}) that describes the | |
759 | target-specific operations; @code{to_stopped_by_watchpoint} ignores | |
760 | the @var{wait_status} argument. | |
761 | ||
762 | @value{GDBN} does not require the non-zero value returned by | |
763 | @code{STOPPED_BY_WATCHPOINT} to be 100% correct, so if a target cannot | |
764 | determine for sure whether the inferior stopped due to a watchpoint, | |
765 | it could return non-zero ``just in case''. | |
9742079a EZ |
766 | @end table |
767 | ||
d983da9c DJ |
768 | @subsection Watchpoints and Threads |
769 | @cindex watchpoints, with threads | |
770 | ||
771 | @value{GDBN} only supports process-wide watchpoints, which trigger | |
772 | in all threads. @value{GDBN} uses the thread ID to make watchpoints | |
773 | act as if they were thread-specific, but it cannot set hardware | |
774 | watchpoints that only trigger in a specific thread. Therefore, even | |
775 | if the target supports threads, per-thread debug registers, and | |
776 | watchpoints which only affect a single thread, it should set the | |
777 | per-thread debug registers for all threads to the same value. On | |
778 | @sc{gnu}/Linux native targets, this is accomplished by using | |
779 | @code{ALL_LWPS} in @code{target_insert_watchpoint} and | |
780 | @code{target_remove_watchpoint} and by using | |
781 | @code{linux_set_new_thread} to register a handler for newly created | |
782 | threads. | |
783 | ||
784 | @value{GDBN}'s @sc{gnu}/Linux support only reports a single event | |
785 | at a time, although multiple events can trigger simultaneously for | |
786 | multi-threaded programs. When multiple events occur, @file{linux-nat.c} | |
787 | queues subsequent events and returns them the next time the program | |
788 | is resumed. This means that @code{STOPPED_BY_WATCHPOINT} and | |
789 | @code{target_stopped_data_address} only need to consult the current | |
790 | thread's state---the thread indicated by @code{inferior_ptid}. If | |
791 | two threads have hit watchpoints simultaneously, those routines | |
792 | will be called a second time for the second thread. | |
793 | ||
9742079a EZ |
794 | @subsection x86 Watchpoints |
795 | @cindex x86 debug registers | |
796 | @cindex watchpoints, on x86 | |
797 | ||
798 | The 32-bit Intel x86 (a.k.a.@: ia32) processors feature special debug | |
799 | registers designed to facilitate debugging. @value{GDBN} provides a | |
800 | generic library of functions that x86-based ports can use to implement | |
801 | support for watchpoints and hardware-assisted breakpoints. This | |
802 | subsection documents the x86 watchpoint facilities in @value{GDBN}. | |
803 | ||
1f70da6a SS |
804 | (At present, the library functions read and write debug registers directly, and are |
805 | thus only available for native configurations.) | |
806 | ||
9742079a EZ |
807 | To use the generic x86 watchpoint support, a port should do the |
808 | following: | |
809 | ||
810 | @itemize @bullet | |
811 | @findex I386_USE_GENERIC_WATCHPOINTS | |
812 | @item | |
813 | Define the macro @code{I386_USE_GENERIC_WATCHPOINTS} somewhere in the | |
814 | target-dependent headers. | |
815 | ||
816 | @item | |
817 | Include the @file{config/i386/nm-i386.h} header file @emph{after} | |
818 | defining @code{I386_USE_GENERIC_WATCHPOINTS}. | |
819 | ||
820 | @item | |
821 | Add @file{i386-nat.o} to the value of the Make variable | |
f0323ca0 | 822 | @code{NATDEPFILES} (@pxref{Native Debugging, NATDEPFILES}). |
9742079a EZ |
823 | |
824 | @item | |
825 | Provide implementations for the @code{I386_DR_LOW_*} macros described | |
826 | below. Typically, each macro should call a target-specific function | |
827 | which does the real work. | |
828 | @end itemize | |
829 | ||
830 | The x86 watchpoint support works by maintaining mirror images of the | |
831 | debug registers. Values are copied between the mirror images and the | |
832 | real debug registers via a set of macros which each target needs to | |
833 | provide: | |
834 | ||
835 | @table @code | |
836 | @findex I386_DR_LOW_SET_CONTROL | |
837 | @item I386_DR_LOW_SET_CONTROL (@var{val}) | |
838 | Set the Debug Control (DR7) register to the value @var{val}. | |
839 | ||
840 | @findex I386_DR_LOW_SET_ADDR | |
841 | @item I386_DR_LOW_SET_ADDR (@var{idx}, @var{addr}) | |
842 | Put the address @var{addr} into the debug register number @var{idx}. | |
843 | ||
844 | @findex I386_DR_LOW_RESET_ADDR | |
845 | @item I386_DR_LOW_RESET_ADDR (@var{idx}) | |
846 | Reset (i.e.@: zero out) the address stored in the debug register | |
847 | number @var{idx}. | |
848 | ||
849 | @findex I386_DR_LOW_GET_STATUS | |
850 | @item I386_DR_LOW_GET_STATUS | |
851 | Return the value of the Debug Status (DR6) register. This value is | |
852 | used immediately after it is returned by | |
853 | @code{I386_DR_LOW_GET_STATUS}, so as to support per-thread status | |
854 | register values. | |
855 | @end table | |
856 | ||
857 | For each one of the 4 debug registers (whose indices are from 0 to 3) | |
858 | that store addresses, a reference count is maintained by @value{GDBN}, | |
859 | to allow sharing of debug registers by several watchpoints. This | |
860 | allows users to define several watchpoints that watch the same | |
861 | expression, but with different conditions and/or commands, without | |
862 | wasting debug registers which are in short supply. @value{GDBN} | |
863 | maintains the reference counts internally, targets don't have to do | |
864 | anything to use this feature. | |
865 | ||
866 | The x86 debug registers can each watch a region that is 1, 2, or 4 | |
867 | bytes long. The ia32 architecture requires that each watched region | |
868 | be appropriately aligned: 2-byte region on 2-byte boundary, 4-byte | |
869 | region on 4-byte boundary. However, the x86 watchpoint support in | |
870 | @value{GDBN} can watch unaligned regions and regions larger than 4 | |
871 | bytes (up to 16 bytes) by allocating several debug registers to watch | |
872 | a single region. This allocation of several registers per a watched | |
873 | region is also done automatically without target code intervention. | |
874 | ||
875 | The generic x86 watchpoint support provides the following API for the | |
876 | @value{GDBN}'s application code: | |
877 | ||
878 | @table @code | |
879 | @findex i386_region_ok_for_watchpoint | |
880 | @item i386_region_ok_for_watchpoint (@var{addr}, @var{len}) | |
881 | The macro @code{TARGET_REGION_OK_FOR_HW_WATCHPOINT} is set to call | |
882 | this function. It counts the number of debug registers required to | |
883 | watch a given region, and returns a non-zero value if that number is | |
884 | less than 4, the number of debug registers available to x86 | |
885 | processors. | |
886 | ||
887 | @findex i386_stopped_data_address | |
ac77d04f JJ |
888 | @item i386_stopped_data_address (@var{addr_p}) |
889 | The target function | |
890 | @code{target_stopped_data_address} is set to call this function. | |
891 | This | |
9742079a EZ |
892 | function examines the breakpoint condition bits in the DR6 Debug |
893 | Status register, as returned by the @code{I386_DR_LOW_GET_STATUS} | |
894 | macro, and returns the address associated with the first bit that is | |
895 | set in DR6. | |
896 | ||
ac77d04f JJ |
897 | @findex i386_stopped_by_watchpoint |
898 | @item i386_stopped_by_watchpoint (void) | |
899 | The macro @code{STOPPED_BY_WATCHPOINT} | |
900 | is set to call this function. The | |
901 | argument passed to @code{STOPPED_BY_WATCHPOINT} is ignored. This | |
902 | function examines the breakpoint condition bits in the DR6 Debug | |
903 | Status register, as returned by the @code{I386_DR_LOW_GET_STATUS} | |
904 | macro, and returns true if any bit is set. Otherwise, false is | |
905 | returned. | |
906 | ||
9742079a EZ |
907 | @findex i386_insert_watchpoint |
908 | @findex i386_remove_watchpoint | |
909 | @item i386_insert_watchpoint (@var{addr}, @var{len}, @var{type}) | |
910 | @itemx i386_remove_watchpoint (@var{addr}, @var{len}, @var{type}) | |
911 | Insert or remove a watchpoint. The macros | |
912 | @code{target_insert_watchpoint} and @code{target_remove_watchpoint} | |
913 | are set to call these functions. @code{i386_insert_watchpoint} first | |
914 | looks for a debug register which is already set to watch the same | |
915 | region for the same access types; if found, it just increments the | |
916 | reference count of that debug register, thus implementing debug | |
917 | register sharing between watchpoints. If no such register is found, | |
937f164b FF |
918 | the function looks for a vacant debug register, sets its mirrored |
919 | value to @var{addr}, sets the mirrored value of DR7 Debug Control | |
9742079a EZ |
920 | register as appropriate for the @var{len} and @var{type} parameters, |
921 | and then passes the new values of the debug register and DR7 to the | |
922 | inferior by calling @code{I386_DR_LOW_SET_ADDR} and | |
923 | @code{I386_DR_LOW_SET_CONTROL}. If more than one debug register is | |
924 | required to cover the given region, the above process is repeated for | |
925 | each debug register. | |
926 | ||
927 | @code{i386_remove_watchpoint} does the opposite: it resets the address | |
937f164b FF |
928 | in the mirrored value of the debug register and its read/write and |
929 | length bits in the mirrored value of DR7, then passes these new | |
9742079a EZ |
930 | values to the inferior via @code{I386_DR_LOW_RESET_ADDR} and |
931 | @code{I386_DR_LOW_SET_CONTROL}. If a register is shared by several | |
932 | watchpoints, each time a @code{i386_remove_watchpoint} is called, it | |
933 | decrements the reference count, and only calls | |
934 | @code{I386_DR_LOW_RESET_ADDR} and @code{I386_DR_LOW_SET_CONTROL} when | |
935 | the count goes to zero. | |
936 | ||
937 | @findex i386_insert_hw_breakpoint | |
938 | @findex i386_remove_hw_breakpoint | |
8181d85f DJ |
939 | @item i386_insert_hw_breakpoint (@var{bp_tgt}) |
940 | @itemx i386_remove_hw_breakpoint (@var{bp_tgt}) | |
9742079a EZ |
941 | These functions insert and remove hardware-assisted breakpoints. The |
942 | macros @code{target_insert_hw_breakpoint} and | |
943 | @code{target_remove_hw_breakpoint} are set to call these functions. | |
8181d85f DJ |
944 | The argument is a @code{struct bp_target_info *}, as described in |
945 | the documentation for @code{target_insert_breakpoint}. | |
9742079a EZ |
946 | These functions work like @code{i386_insert_watchpoint} and |
947 | @code{i386_remove_watchpoint}, respectively, except that they set up | |
948 | the debug registers to watch instruction execution, and each | |
949 | hardware-assisted breakpoint always requires exactly one debug | |
950 | register. | |
951 | ||
952 | @findex i386_stopped_by_hwbp | |
953 | @item i386_stopped_by_hwbp (void) | |
954 | This function returns non-zero if the inferior has some watchpoint or | |
955 | hardware breakpoint that triggered. It works like | |
ac77d04f | 956 | @code{i386_stopped_data_address}, except that it doesn't record the |
9742079a EZ |
957 | address whose watchpoint triggered. |
958 | ||
959 | @findex i386_cleanup_dregs | |
960 | @item i386_cleanup_dregs (void) | |
961 | This function clears all the reference counts, addresses, and control | |
962 | bits in the mirror images of the debug registers. It doesn't affect | |
963 | the actual debug registers in the inferior process. | |
964 | @end table | |
965 | ||
966 | @noindent | |
967 | @strong{Notes:} | |
968 | @enumerate 1 | |
969 | @item | |
970 | x86 processors support setting watchpoints on I/O reads or writes. | |
971 | However, since no target supports this (as of March 2001), and since | |
972 | @code{enum target_hw_bp_type} doesn't even have an enumeration for I/O | |
973 | watchpoints, this feature is not yet available to @value{GDBN} running | |
974 | on x86. | |
975 | ||
976 | @item | |
977 | x86 processors can enable watchpoints locally, for the current task | |
978 | only, or globally, for all the tasks. For each debug register, | |
979 | there's a bit in the DR7 Debug Control register that determines | |
980 | whether the associated address is watched locally or globally. The | |
981 | current implementation of x86 watchpoint support in @value{GDBN} | |
982 | always sets watchpoints to be locally enabled, since global | |
983 | watchpoints might interfere with the underlying OS and are probably | |
984 | unavailable in many platforms. | |
985 | @end enumerate | |
986 | ||
5c95884b MS |
987 | @section Checkpoints |
988 | @cindex checkpoints | |
989 | @cindex restart | |
990 | In the abstract, a checkpoint is a point in the execution history of | |
991 | the program, which the user may wish to return to at some later time. | |
992 | ||
993 | Internally, a checkpoint is a saved copy of the program state, including | |
994 | whatever information is required in order to restore the program to that | |
995 | state at a later time. This can be expected to include the state of | |
996 | registers and memory, and may include external state such as the state | |
997 | of open files and devices. | |
998 | ||
999 | There are a number of ways in which checkpoints may be implemented | |
b247355e | 1000 | in gdb, e.g.@: as corefiles, as forked processes, and as some opaque |
5c95884b MS |
1001 | method implemented on the target side. |
1002 | ||
1003 | A corefile can be used to save an image of target memory and register | |
1004 | state, which can in principle be restored later --- but corefiles do | |
1005 | not typically include information about external entities such as | |
1006 | open files. Currently this method is not implemented in gdb. | |
1007 | ||
1008 | A forked process can save the state of user memory and registers, | |
1009 | as well as some subset of external (kernel) state. This method | |
1010 | is used to implement checkpoints on Linux, and in principle might | |
1011 | be used on other systems. | |
1012 | ||
b247355e | 1013 | Some targets, e.g.@: simulators, might have their own built-in |
5c95884b MS |
1014 | method for saving checkpoints, and gdb might be able to take |
1015 | advantage of that capability without necessarily knowing any | |
1016 | details of how it is done. | |
1017 | ||
1018 | ||
bcd7e15f JB |
1019 | @section Observing changes in @value{GDBN} internals |
1020 | @cindex observer pattern interface | |
1021 | @cindex notifications about changes in internals | |
1022 | ||
1023 | In order to function properly, several modules need to be notified when | |
1024 | some changes occur in the @value{GDBN} internals. Traditionally, these | |
1025 | modules have relied on several paradigms, the most common ones being | |
1026 | hooks and gdb-events. Unfortunately, none of these paradigms was | |
1027 | versatile enough to become the standard notification mechanism in | |
1028 | @value{GDBN}. The fact that they only supported one ``client'' was also | |
1029 | a strong limitation. | |
1030 | ||
1031 | A new paradigm, based on the Observer pattern of the @cite{Design | |
1032 | Patterns} book, has therefore been implemented. The goal was to provide | |
1033 | a new interface overcoming the issues with the notification mechanisms | |
1034 | previously available. This new interface needed to be strongly typed, | |
1035 | easy to extend, and versatile enough to be used as the standard | |
1036 | interface when adding new notifications. | |
1037 | ||
1038 | See @ref{GDB Observers} for a brief description of the observers | |
1039 | currently implemented in GDB. The rationale for the current | |
1040 | implementation is also briefly discussed. | |
1041 | ||
c906108c SS |
1042 | @node User Interface |
1043 | ||
1044 | @chapter User Interface | |
1045 | ||
1f70da6a SS |
1046 | @value{GDBN} has several user interfaces, of which the traditional |
1047 | command-line interface is perhaps the most familiar. | |
c906108c SS |
1048 | |
1049 | @section Command Interpreter | |
1050 | ||
56caf160 | 1051 | @cindex command interpreter |
0ee54786 | 1052 | @cindex CLI |
25822942 | 1053 | The command interpreter in @value{GDBN} is fairly simple. It is designed to |
c906108c SS |
1054 | allow for the set of commands to be augmented dynamically, and also |
1055 | has a recursive subcommand capability, where the first argument to | |
1056 | a command may itself direct a lookup on a different command list. | |
1057 | ||
56caf160 EZ |
1058 | For instance, the @samp{set} command just starts a lookup on the |
1059 | @code{setlist} command list, while @samp{set thread} recurses | |
c906108c SS |
1060 | to the @code{set_thread_cmd_list}. |
1061 | ||
56caf160 EZ |
1062 | @findex add_cmd |
1063 | @findex add_com | |
c906108c SS |
1064 | To add commands in general, use @code{add_cmd}. @code{add_com} adds to |
1065 | the main command list, and should be used for those commands. The usual | |
cfeada60 | 1066 | place to add commands is in the @code{_initialize_@var{xyz}} routines at |
9742079a | 1067 | the ends of most source files. |
cfeada60 | 1068 | |
40dd2248 TT |
1069 | @findex add_setshow_cmd |
1070 | @findex add_setshow_cmd_full | |
1071 | To add paired @samp{set} and @samp{show} commands, use | |
1072 | @code{add_setshow_cmd} or @code{add_setshow_cmd_full}. The former is | |
1073 | a slightly simpler interface which is useful when you don't need to | |
1074 | further modify the new command structures, while the latter returns | |
1075 | the new command structures for manipulation. | |
1076 | ||
56caf160 EZ |
1077 | @cindex deprecating commands |
1078 | @findex deprecate_cmd | |
cfeada60 FN |
1079 | Before removing commands from the command set it is a good idea to |
1080 | deprecate them for some time. Use @code{deprecate_cmd} on commands or | |
1081 | aliases to set the deprecated flag. @code{deprecate_cmd} takes a | |
1082 | @code{struct cmd_list_element} as it's first argument. You can use the | |
1083 | return value from @code{add_com} or @code{add_cmd} to deprecate the | |
1084 | command immediately after it is created. | |
1085 | ||
c72e7388 | 1086 | The first time a command is used the user will be warned and offered a |
cfeada60 | 1087 | replacement (if one exists). Note that the replacement string passed to |
d3e8051b | 1088 | @code{deprecate_cmd} should be the full name of the command, i.e., the |
cfeada60 | 1089 | entire string the user should type at the command line. |
c906108c | 1090 | |
0ee54786 EZ |
1091 | @section UI-Independent Output---the @code{ui_out} Functions |
1092 | @c This section is based on the documentation written by Fernando | |
1093 | @c Nasser <fnasser@redhat.com>. | |
1094 | ||
1095 | @cindex @code{ui_out} functions | |
1096 | The @code{ui_out} functions present an abstraction level for the | |
1097 | @value{GDBN} output code. They hide the specifics of different user | |
1098 | interfaces supported by @value{GDBN}, and thus free the programmer | |
1099 | from the need to write several versions of the same code, one each for | |
1100 | every UI, to produce output. | |
1101 | ||
1102 | @subsection Overview and Terminology | |
1103 | ||
1104 | In general, execution of each @value{GDBN} command produces some sort | |
1105 | of output, and can even generate an input request. | |
1106 | ||
1107 | Output can be generated for the following purposes: | |
1108 | ||
1109 | @itemize @bullet | |
1110 | @item | |
1111 | to display a @emph{result} of an operation; | |
1112 | ||
1113 | @item | |
1114 | to convey @emph{info} or produce side-effects of a requested | |
1115 | operation; | |
1116 | ||
1117 | @item | |
1118 | to provide a @emph{notification} of an asynchronous event (including | |
1119 | progress indication of a prolonged asynchronous operation); | |
1120 | ||
1121 | @item | |
1122 | to display @emph{error messages} (including warnings); | |
1123 | ||
1124 | @item | |
1125 | to show @emph{debug data}; | |
1126 | ||
1127 | @item | |
1128 | to @emph{query} or prompt a user for input (a special case). | |
1129 | @end itemize | |
1130 | ||
1131 | @noindent | |
1132 | This section mainly concentrates on how to build result output, | |
1133 | although some of it also applies to other kinds of output. | |
1134 | ||
1135 | Generation of output that displays the results of an operation | |
1136 | involves one or more of the following: | |
1137 | ||
1138 | @itemize @bullet | |
1139 | @item | |
1140 | output of the actual data | |
1141 | ||
1142 | @item | |
1143 | formatting the output as appropriate for console output, to make it | |
1144 | easily readable by humans | |
1145 | ||
1146 | @item | |
1147 | machine oriented formatting--a more terse formatting to allow for easy | |
1148 | parsing by programs which read @value{GDBN}'s output | |
1149 | ||
1150 | @item | |
c72e7388 AC |
1151 | annotation, whose purpose is to help legacy GUIs to identify interesting |
1152 | parts in the output | |
0ee54786 EZ |
1153 | @end itemize |
1154 | ||
1155 | The @code{ui_out} routines take care of the first three aspects. | |
c72e7388 AC |
1156 | Annotations are provided by separate annotation routines. Note that use |
1157 | of annotations for an interface between a GUI and @value{GDBN} is | |
0ee54786 EZ |
1158 | deprecated. |
1159 | ||
c72e7388 AC |
1160 | Output can be in the form of a single item, which we call a @dfn{field}; |
1161 | a @dfn{list} consisting of identical fields; a @dfn{tuple} consisting of | |
1162 | non-identical fields; or a @dfn{table}, which is a tuple consisting of a | |
1163 | header and a body. In a BNF-like form: | |
0ee54786 | 1164 | |
c72e7388 AC |
1165 | @table @code |
1166 | @item <table> @expansion{} | |
1167 | @code{<header> <body>} | |
1168 | @item <header> @expansion{} | |
1169 | @code{@{ <column> @}} | |
1170 | @item <column> @expansion{} | |
1171 | @code{<width> <alignment> <title>} | |
1172 | @item <body> @expansion{} | |
1173 | @code{@{<row>@}} | |
1174 | @end table | |
0ee54786 EZ |
1175 | |
1176 | ||
1177 | @subsection General Conventions | |
1178 | ||
c72e7388 AC |
1179 | Most @code{ui_out} routines are of type @code{void}, the exceptions are |
1180 | @code{ui_out_stream_new} (which returns a pointer to the newly created | |
1181 | object) and the @code{make_cleanup} routines. | |
0ee54786 | 1182 | |
c72e7388 AC |
1183 | The first parameter is always the @code{ui_out} vector object, a pointer |
1184 | to a @code{struct ui_out}. | |
0ee54786 | 1185 | |
c72e7388 AC |
1186 | The @var{format} parameter is like in @code{printf} family of functions. |
1187 | When it is present, there must also be a variable list of arguments | |
1188 | sufficient used to satisfy the @code{%} specifiers in the supplied | |
0ee54786 EZ |
1189 | format. |
1190 | ||
c72e7388 AC |
1191 | When a character string argument is not used in a @code{ui_out} function |
1192 | call, a @code{NULL} pointer has to be supplied instead. | |
0ee54786 EZ |
1193 | |
1194 | ||
c72e7388 | 1195 | @subsection Table, Tuple and List Functions |
0ee54786 EZ |
1196 | |
1197 | @cindex list output functions | |
1198 | @cindex table output functions | |
c72e7388 AC |
1199 | @cindex tuple output functions |
1200 | This section introduces @code{ui_out} routines for building lists, | |
1201 | tuples and tables. The routines to output the actual data items | |
1202 | (fields) are presented in the next section. | |
0ee54786 | 1203 | |
c72e7388 AC |
1204 | To recap: A @dfn{tuple} is a sequence of @dfn{fields}, each field |
1205 | containing information about an object; a @dfn{list} is a sequence of | |
1206 | fields where each field describes an identical object. | |
0ee54786 | 1207 | |
c72e7388 AC |
1208 | Use the @dfn{table} functions when your output consists of a list of |
1209 | rows (tuples) and the console output should include a heading. Use this | |
1210 | even when you are listing just one object but you still want the header. | |
0ee54786 EZ |
1211 | |
1212 | @cindex nesting level in @code{ui_out} functions | |
c72e7388 AC |
1213 | Tables can not be nested. Tuples and lists can be nested up to a |
1214 | maximum of five levels. | |
0ee54786 EZ |
1215 | |
1216 | The overall structure of the table output code is something like this: | |
1217 | ||
474c8240 | 1218 | @smallexample |
0ee54786 EZ |
1219 | ui_out_table_begin |
1220 | ui_out_table_header | |
c72e7388 | 1221 | @dots{} |
0ee54786 | 1222 | ui_out_table_body |
c72e7388 | 1223 | ui_out_tuple_begin |
0ee54786 | 1224 | ui_out_field_* |
c72e7388 AC |
1225 | @dots{} |
1226 | ui_out_tuple_end | |
1227 | @dots{} | |
0ee54786 | 1228 | ui_out_table_end |
474c8240 | 1229 | @end smallexample |
0ee54786 | 1230 | |
c72e7388 | 1231 | Here is the description of table-, tuple- and list-related @code{ui_out} |
0ee54786 EZ |
1232 | functions: |
1233 | ||
c72e7388 AC |
1234 | @deftypefun void ui_out_table_begin (struct ui_out *@var{uiout}, int @var{nbrofcols}, int @var{nr_rows}, const char *@var{tblid}) |
1235 | The function @code{ui_out_table_begin} marks the beginning of the output | |
1236 | of a table. It should always be called before any other @code{ui_out} | |
1237 | function for a given table. @var{nbrofcols} is the number of columns in | |
1238 | the table. @var{nr_rows} is the number of rows in the table. | |
1239 | @var{tblid} is an optional string identifying the table. The string | |
1240 | pointed to by @var{tblid} is copied by the implementation of | |
1241 | @code{ui_out_table_begin}, so the application can free the string if it | |
1242 | was @code{malloc}ed. | |
0ee54786 EZ |
1243 | |
1244 | The companion function @code{ui_out_table_end}, described below, marks | |
1245 | the end of the table's output. | |
1246 | @end deftypefun | |
1247 | ||
c72e7388 AC |
1248 | @deftypefun void ui_out_table_header (struct ui_out *@var{uiout}, int @var{width}, enum ui_align @var{alignment}, const char *@var{colhdr}) |
1249 | @code{ui_out_table_header} provides the header information for a single | |
1250 | table column. You call this function several times, one each for every | |
1251 | column of the table, after @code{ui_out_table_begin}, but before | |
1252 | @code{ui_out_table_body}. | |
0ee54786 EZ |
1253 | |
1254 | The value of @var{width} gives the column width in characters. The | |
1255 | value of @var{alignment} is one of @code{left}, @code{center}, and | |
1256 | @code{right}, and it specifies how to align the header: left-justify, | |
1257 | center, or right-justify it. @var{colhdr} points to a string that | |
1258 | specifies the column header; the implementation copies that string, so | |
c72e7388 AC |
1259 | column header strings in @code{malloc}ed storage can be freed after the |
1260 | call. | |
0ee54786 EZ |
1261 | @end deftypefun |
1262 | ||
1263 | @deftypefun void ui_out_table_body (struct ui_out *@var{uiout}) | |
c72e7388 | 1264 | This function delimits the table header from the table body. |
0ee54786 EZ |
1265 | @end deftypefun |
1266 | ||
1267 | @deftypefun void ui_out_table_end (struct ui_out *@var{uiout}) | |
c72e7388 AC |
1268 | This function signals the end of a table's output. It should be called |
1269 | after the table body has been produced by the list and field output | |
1270 | functions. | |
0ee54786 EZ |
1271 | |
1272 | There should be exactly one call to @code{ui_out_table_end} for each | |
c72e7388 AC |
1273 | call to @code{ui_out_table_begin}, otherwise the @code{ui_out} functions |
1274 | will signal an internal error. | |
0ee54786 EZ |
1275 | @end deftypefun |
1276 | ||
c72e7388 | 1277 | The output of the tuples that represent the table rows must follow the |
0ee54786 | 1278 | call to @code{ui_out_table_body} and precede the call to |
c72e7388 AC |
1279 | @code{ui_out_table_end}. You build a tuple by calling |
1280 | @code{ui_out_tuple_begin} and @code{ui_out_tuple_end}, with suitable | |
0ee54786 EZ |
1281 | calls to functions which actually output fields between them. |
1282 | ||
c72e7388 AC |
1283 | @deftypefun void ui_out_tuple_begin (struct ui_out *@var{uiout}, const char *@var{id}) |
1284 | This function marks the beginning of a tuple output. @var{id} points | |
1285 | to an optional string that identifies the tuple; it is copied by the | |
1286 | implementation, and so strings in @code{malloc}ed storage can be freed | |
1287 | after the call. | |
1288 | @end deftypefun | |
1289 | ||
1290 | @deftypefun void ui_out_tuple_end (struct ui_out *@var{uiout}) | |
1291 | This function signals an end of a tuple output. There should be exactly | |
1292 | one call to @code{ui_out_tuple_end} for each call to | |
1293 | @code{ui_out_tuple_begin}, otherwise an internal @value{GDBN} error will | |
1294 | be signaled. | |
1295 | @end deftypefun | |
1296 | ||
1297 | @deftypefun struct cleanup *make_cleanup_ui_out_tuple_begin_end (struct ui_out *@var{uiout}, const char *@var{id}) | |
1298 | This function first opens the tuple and then establishes a cleanup | |
1299 | (@pxref{Coding, Cleanups}) to close the tuple. It provides a convenient | |
1300 | and correct implementation of the non-portable@footnote{The function | |
b9aa90c9 | 1301 | cast is not portable ISO C.} code sequence: |
c72e7388 AC |
1302 | @smallexample |
1303 | struct cleanup *old_cleanup; | |
1304 | ui_out_tuple_begin (uiout, "..."); | |
1305 | old_cleanup = make_cleanup ((void(*)(void *)) ui_out_tuple_end, | |
1306 | uiout); | |
1307 | @end smallexample | |
1308 | @end deftypefun | |
1309 | ||
1310 | @deftypefun void ui_out_list_begin (struct ui_out *@var{uiout}, const char *@var{id}) | |
1311 | This function marks the beginning of a list output. @var{id} points to | |
1312 | an optional string that identifies the list; it is copied by the | |
1313 | implementation, and so strings in @code{malloc}ed storage can be freed | |
1314 | after the call. | |
0ee54786 EZ |
1315 | @end deftypefun |
1316 | ||
1317 | @deftypefun void ui_out_list_end (struct ui_out *@var{uiout}) | |
c72e7388 AC |
1318 | This function signals an end of a list output. There should be exactly |
1319 | one call to @code{ui_out_list_end} for each call to | |
1320 | @code{ui_out_list_begin}, otherwise an internal @value{GDBN} error will | |
1321 | be signaled. | |
1322 | @end deftypefun | |
1323 | ||
1324 | @deftypefun struct cleanup *make_cleanup_ui_out_list_begin_end (struct ui_out *@var{uiout}, const char *@var{id}) | |
1325 | Similar to @code{make_cleanup_ui_out_tuple_begin_end}, this function | |
1326 | opens a list and then establishes cleanup (@pxref{Coding, Cleanups}) | |
f66d1690 | 1327 | that will close the list. |
0ee54786 EZ |
1328 | @end deftypefun |
1329 | ||
1330 | @subsection Item Output Functions | |
1331 | ||
1332 | @cindex item output functions | |
1333 | @cindex field output functions | |
1334 | @cindex data output | |
1335 | The functions described below produce output for the actual data | |
1336 | items, or fields, which contain information about the object. | |
1337 | ||
1338 | Choose the appropriate function accordingly to your particular needs. | |
1339 | ||
1340 | @deftypefun void ui_out_field_fmt (struct ui_out *@var{uiout}, char *@var{fldname}, char *@var{format}, ...) | |
1341 | This is the most general output function. It produces the | |
1342 | representation of the data in the variable-length argument list | |
1343 | according to formatting specifications in @var{format}, a | |
1344 | @code{printf}-like format string. The optional argument @var{fldname} | |
1345 | supplies the name of the field. The data items themselves are | |
1346 | supplied as additional arguments after @var{format}. | |
1347 | ||
1348 | This generic function should be used only when it is not possible to | |
1349 | use one of the specialized versions (see below). | |
1350 | @end deftypefun | |
1351 | ||
c72e7388 | 1352 | @deftypefun void ui_out_field_int (struct ui_out *@var{uiout}, const char *@var{fldname}, int @var{value}) |
0ee54786 EZ |
1353 | This function outputs a value of an @code{int} variable. It uses the |
1354 | @code{"%d"} output conversion specification. @var{fldname} specifies | |
1355 | the name of the field. | |
1356 | @end deftypefun | |
8d19fbd2 JJ |
1357 | |
1358 | @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}) | |
1359 | This function outputs a value of an @code{int} variable. It differs from | |
1360 | @code{ui_out_field_int} in that the caller specifies the desired @var{width} and @var{alignment} of the output. | |
1361 | @var{fldname} specifies | |
1362 | the name of the field. | |
1363 | @end deftypefun | |
0ee54786 | 1364 | |
c72e7388 | 1365 | @deftypefun void ui_out_field_core_addr (struct ui_out *@var{uiout}, const char *@var{fldname}, CORE_ADDR @var{address}) |
0ee54786 EZ |
1366 | This function outputs an address. |
1367 | @end deftypefun | |
1368 | ||
c72e7388 | 1369 | @deftypefun void ui_out_field_string (struct ui_out *@var{uiout}, const char *@var{fldname}, const char *@var{string}) |
0ee54786 EZ |
1370 | This function outputs a string using the @code{"%s"} conversion |
1371 | specification. | |
1372 | @end deftypefun | |
1373 | ||
1374 | Sometimes, there's a need to compose your output piece by piece using | |
1375 | functions that operate on a stream, such as @code{value_print} or | |
1376 | @code{fprintf_symbol_filtered}. These functions accept an argument of | |
1377 | the type @code{struct ui_file *}, a pointer to a @code{ui_file} object | |
1378 | used to store the data stream used for the output. When you use one | |
1379 | of these functions, you need a way to pass their results stored in a | |
1380 | @code{ui_file} object to the @code{ui_out} functions. To this end, | |
1381 | you first create a @code{ui_stream} object by calling | |
1382 | @code{ui_out_stream_new}, pass the @code{stream} member of that | |
1383 | @code{ui_stream} object to @code{value_print} and similar functions, | |
1384 | and finally call @code{ui_out_field_stream} to output the field you | |
1385 | constructed. When the @code{ui_stream} object is no longer needed, | |
1386 | you should destroy it and free its memory by calling | |
1387 | @code{ui_out_stream_delete}. | |
1388 | ||
1389 | @deftypefun struct ui_stream *ui_out_stream_new (struct ui_out *@var{uiout}) | |
1390 | This function creates a new @code{ui_stream} object which uses the | |
1391 | same output methods as the @code{ui_out} object whose pointer is | |
1392 | passed in @var{uiout}. It returns a pointer to the newly created | |
1393 | @code{ui_stream} object. | |
1394 | @end deftypefun | |
1395 | ||
1396 | @deftypefun void ui_out_stream_delete (struct ui_stream *@var{streambuf}) | |
1397 | This functions destroys a @code{ui_stream} object specified by | |
1398 | @var{streambuf}. | |
1399 | @end deftypefun | |
1400 | ||
c72e7388 | 1401 | @deftypefun void ui_out_field_stream (struct ui_out *@var{uiout}, const char *@var{fieldname}, struct ui_stream *@var{streambuf}) |
0ee54786 EZ |
1402 | This function consumes all the data accumulated in |
1403 | @code{streambuf->stream} and outputs it like | |
1404 | @code{ui_out_field_string} does. After a call to | |
1405 | @code{ui_out_field_stream}, the accumulated data no longer exists, but | |
1406 | the stream is still valid and may be used for producing more fields. | |
1407 | @end deftypefun | |
1408 | ||
1409 | @strong{Important:} If there is any chance that your code could bail | |
1410 | out before completing output generation and reaching the point where | |
1411 | @code{ui_out_stream_delete} is called, it is necessary to set up a | |
1412 | cleanup, to avoid leaking memory and other resources. Here's a | |
1413 | skeleton code to do that: | |
1414 | ||
1415 | @smallexample | |
1416 | struct ui_stream *mybuf = ui_out_stream_new (uiout); | |
1417 | struct cleanup *old = make_cleanup (ui_out_stream_delete, mybuf); | |
1418 | ... | |
1419 | do_cleanups (old); | |
1420 | @end smallexample | |
1421 | ||
1422 | If the function already has the old cleanup chain set (for other kinds | |
1423 | of cleanups), you just have to add your cleanup to it: | |
1424 | ||
1425 | @smallexample | |
1426 | mybuf = ui_out_stream_new (uiout); | |
1427 | make_cleanup (ui_out_stream_delete, mybuf); | |
1428 | @end smallexample | |
1429 | ||
1430 | Note that with cleanups in place, you should not call | |
1431 | @code{ui_out_stream_delete} directly, or you would attempt to free the | |
1432 | same buffer twice. | |
1433 | ||
1434 | @subsection Utility Output Functions | |
1435 | ||
c72e7388 | 1436 | @deftypefun void ui_out_field_skip (struct ui_out *@var{uiout}, const char *@var{fldname}) |
0ee54786 EZ |
1437 | This function skips a field in a table. Use it if you have to leave |
1438 | an empty field without disrupting the table alignment. The argument | |
1439 | @var{fldname} specifies a name for the (missing) filed. | |
1440 | @end deftypefun | |
1441 | ||
c72e7388 | 1442 | @deftypefun void ui_out_text (struct ui_out *@var{uiout}, const char *@var{string}) |
0ee54786 EZ |
1443 | This function outputs the text in @var{string} in a way that makes it |
1444 | easy to be read by humans. For example, the console implementation of | |
1445 | this method filters the text through a built-in pager, to prevent it | |
1446 | from scrolling off the visible portion of the screen. | |
1447 | ||
1448 | Use this function for printing relatively long chunks of text around | |
1449 | the actual field data: the text it produces is not aligned according | |
1450 | to the table's format. Use @code{ui_out_field_string} to output a | |
1451 | string field, and use @code{ui_out_message}, described below, to | |
1452 | output short messages. | |
1453 | @end deftypefun | |
1454 | ||
1455 | @deftypefun void ui_out_spaces (struct ui_out *@var{uiout}, int @var{nspaces}) | |
1456 | This function outputs @var{nspaces} spaces. It is handy to align the | |
1457 | text produced by @code{ui_out_text} with the rest of the table or | |
1458 | list. | |
1459 | @end deftypefun | |
1460 | ||
c72e7388 | 1461 | @deftypefun void ui_out_message (struct ui_out *@var{uiout}, int @var{verbosity}, const char *@var{format}, ...) |
0ee54786 EZ |
1462 | This function produces a formatted message, provided that the current |
1463 | verbosity level is at least as large as given by @var{verbosity}. The | |
1464 | current verbosity level is specified by the user with the @samp{set | |
1465 | verbositylevel} command.@footnote{As of this writing (April 2001), | |
1466 | setting verbosity level is not yet implemented, and is always returned | |
1467 | as zero. So calling @code{ui_out_message} with a @var{verbosity} | |
1468 | argument more than zero will cause the message to never be printed.} | |
1469 | @end deftypefun | |
1470 | ||
1471 | @deftypefun void ui_out_wrap_hint (struct ui_out *@var{uiout}, char *@var{indent}) | |
1472 | This function gives the console output filter (a paging filter) a hint | |
1473 | of where to break lines which are too long. Ignored for all other | |
1474 | output consumers. @var{indent}, if non-@code{NULL}, is the string to | |
1475 | be printed to indent the wrapped text on the next line; it must remain | |
1476 | accessible until the next call to @code{ui_out_wrap_hint}, or until an | |
1477 | explicit newline is produced by one of the other functions. If | |
1478 | @var{indent} is @code{NULL}, the wrapped text will not be indented. | |
1479 | @end deftypefun | |
1480 | ||
1481 | @deftypefun void ui_out_flush (struct ui_out *@var{uiout}) | |
1482 | This function flushes whatever output has been accumulated so far, if | |
1483 | the UI buffers output. | |
1484 | @end deftypefun | |
1485 | ||
1486 | ||
1487 | @subsection Examples of Use of @code{ui_out} functions | |
1488 | ||
1489 | @cindex using @code{ui_out} functions | |
1490 | @cindex @code{ui_out} functions, usage examples | |
1491 | This section gives some practical examples of using the @code{ui_out} | |
1492 | functions to generalize the old console-oriented code in | |
1493 | @value{GDBN}. The examples all come from functions defined on the | |
1494 | @file{breakpoints.c} file. | |
1495 | ||
1496 | This example, from the @code{breakpoint_1} function, shows how to | |
1497 | produce a table. | |
1498 | ||
1499 | The original code was: | |
1500 | ||
474c8240 | 1501 | @smallexample |
0ee54786 EZ |
1502 | if (!found_a_breakpoint++) |
1503 | @{ | |
1504 | annotate_breakpoints_headers (); | |
1505 | ||
1506 | annotate_field (0); | |
1507 | printf_filtered ("Num "); | |
1508 | annotate_field (1); | |
1509 | printf_filtered ("Type "); | |
1510 | annotate_field (2); | |
1511 | printf_filtered ("Disp "); | |
1512 | annotate_field (3); | |
1513 | printf_filtered ("Enb "); | |
1514 | if (addressprint) | |
1515 | @{ | |
1516 | annotate_field (4); | |
1517 | printf_filtered ("Address "); | |
1518 | @} | |
1519 | annotate_field (5); | |
1520 | printf_filtered ("What\n"); | |
1521 | ||
1522 | annotate_breakpoints_table (); | |
1523 | @} | |
474c8240 | 1524 | @end smallexample |
0ee54786 EZ |
1525 | |
1526 | Here's the new version: | |
1527 | ||
474c8240 | 1528 | @smallexample |
c72e7388 AC |
1529 | nr_printable_breakpoints = @dots{}; |
1530 | ||
1531 | if (addressprint) | |
1532 | ui_out_table_begin (ui, 6, nr_printable_breakpoints, "BreakpointTable"); | |
1533 | else | |
1534 | ui_out_table_begin (ui, 5, nr_printable_breakpoints, "BreakpointTable"); | |
1535 | ||
1536 | if (nr_printable_breakpoints > 0) | |
1537 | annotate_breakpoints_headers (); | |
1538 | if (nr_printable_breakpoints > 0) | |
1539 | annotate_field (0); | |
1540 | ui_out_table_header (uiout, 3, ui_left, "number", "Num"); /* 1 */ | |
1541 | if (nr_printable_breakpoints > 0) | |
1542 | annotate_field (1); | |
1543 | ui_out_table_header (uiout, 14, ui_left, "type", "Type"); /* 2 */ | |
1544 | if (nr_printable_breakpoints > 0) | |
1545 | annotate_field (2); | |
1546 | ui_out_table_header (uiout, 4, ui_left, "disp", "Disp"); /* 3 */ | |
1547 | if (nr_printable_breakpoints > 0) | |
1548 | annotate_field (3); | |
1549 | ui_out_table_header (uiout, 3, ui_left, "enabled", "Enb"); /* 4 */ | |
1550 | if (addressprint) | |
1551 | @{ | |
1552 | if (nr_printable_breakpoints > 0) | |
1553 | annotate_field (4); | |
4a9bb1df | 1554 | if (gdbarch_addr_bit (current_gdbarch) <= 32) |
c72e7388 | 1555 | ui_out_table_header (uiout, 10, ui_left, "addr", "Address");/* 5 */ |
0ee54786 | 1556 | else |
c72e7388 AC |
1557 | ui_out_table_header (uiout, 18, ui_left, "addr", "Address");/* 5 */ |
1558 | @} | |
1559 | if (nr_printable_breakpoints > 0) | |
1560 | annotate_field (5); | |
1561 | ui_out_table_header (uiout, 40, ui_noalign, "what", "What"); /* 6 */ | |
1562 | ui_out_table_body (uiout); | |
1563 | if (nr_printable_breakpoints > 0) | |
1564 | annotate_breakpoints_table (); | |
474c8240 | 1565 | @end smallexample |
0ee54786 EZ |
1566 | |
1567 | This example, from the @code{print_one_breakpoint} function, shows how | |
1568 | to produce the actual data for the table whose structure was defined | |
1569 | in the above example. The original code was: | |
1570 | ||
474c8240 | 1571 | @smallexample |
0ee54786 EZ |
1572 | annotate_record (); |
1573 | annotate_field (0); | |
1574 | printf_filtered ("%-3d ", b->number); | |
1575 | annotate_field (1); | |
1576 | if ((int)b->type > (sizeof(bptypes)/sizeof(bptypes[0])) | |
1577 | || ((int) b->type != bptypes[(int) b->type].type)) | |
1578 | internal_error ("bptypes table does not describe type #%d.", | |
1579 | (int)b->type); | |
1580 | printf_filtered ("%-14s ", bptypes[(int)b->type].description); | |
1581 | annotate_field (2); | |
1582 | printf_filtered ("%-4s ", bpdisps[(int)b->disposition]); | |
1583 | annotate_field (3); | |
1584 | printf_filtered ("%-3c ", bpenables[(int)b->enable]); | |
c72e7388 | 1585 | @dots{} |
474c8240 | 1586 | @end smallexample |
0ee54786 EZ |
1587 | |
1588 | This is the new version: | |
1589 | ||
474c8240 | 1590 | @smallexample |
0ee54786 | 1591 | annotate_record (); |
c72e7388 | 1592 | ui_out_tuple_begin (uiout, "bkpt"); |
0ee54786 EZ |
1593 | annotate_field (0); |
1594 | ui_out_field_int (uiout, "number", b->number); | |
1595 | annotate_field (1); | |
1596 | if (((int) b->type > (sizeof (bptypes) / sizeof (bptypes[0]))) | |
1597 | || ((int) b->type != bptypes[(int) b->type].type)) | |
1598 | internal_error ("bptypes table does not describe type #%d.", | |
1599 | (int) b->type); | |
1600 | ui_out_field_string (uiout, "type", bptypes[(int)b->type].description); | |
1601 | annotate_field (2); | |
1602 | ui_out_field_string (uiout, "disp", bpdisps[(int)b->disposition]); | |
1603 | annotate_field (3); | |
1604 | ui_out_field_fmt (uiout, "enabled", "%c", bpenables[(int)b->enable]); | |
c72e7388 | 1605 | @dots{} |
474c8240 | 1606 | @end smallexample |
0ee54786 EZ |
1607 | |
1608 | This example, also from @code{print_one_breakpoint}, shows how to | |
1609 | produce a complicated output field using the @code{print_expression} | |
1610 | functions which requires a stream to be passed. It also shows how to | |
1611 | automate stream destruction with cleanups. The original code was: | |
1612 | ||
474c8240 | 1613 | @smallexample |
0ee54786 EZ |
1614 | annotate_field (5); |
1615 | print_expression (b->exp, gdb_stdout); | |
474c8240 | 1616 | @end smallexample |
0ee54786 EZ |
1617 | |
1618 | The new version is: | |
1619 | ||
474c8240 | 1620 | @smallexample |
0ee54786 EZ |
1621 | struct ui_stream *stb = ui_out_stream_new (uiout); |
1622 | struct cleanup *old_chain = make_cleanup_ui_out_stream_delete (stb); | |
1623 | ... | |
1624 | annotate_field (5); | |
1625 | print_expression (b->exp, stb->stream); | |
1626 | ui_out_field_stream (uiout, "what", local_stream); | |
474c8240 | 1627 | @end smallexample |
0ee54786 EZ |
1628 | |
1629 | This example, also from @code{print_one_breakpoint}, shows how to use | |
1630 | @code{ui_out_text} and @code{ui_out_field_string}. The original code | |
1631 | was: | |
1632 | ||
474c8240 | 1633 | @smallexample |
0ee54786 EZ |
1634 | annotate_field (5); |
1635 | if (b->dll_pathname == NULL) | |
1636 | printf_filtered ("<any library> "); | |
1637 | else | |
1638 | printf_filtered ("library \"%s\" ", b->dll_pathname); | |
474c8240 | 1639 | @end smallexample |
0ee54786 EZ |
1640 | |
1641 | It became: | |
1642 | ||
474c8240 | 1643 | @smallexample |
0ee54786 EZ |
1644 | annotate_field (5); |
1645 | if (b->dll_pathname == NULL) | |
1646 | @{ | |
1647 | ui_out_field_string (uiout, "what", "<any library>"); | |
1648 | ui_out_spaces (uiout, 1); | |
1649 | @} | |
1650 | else | |
1651 | @{ | |
1652 | ui_out_text (uiout, "library \""); | |
1653 | ui_out_field_string (uiout, "what", b->dll_pathname); | |
1654 | ui_out_text (uiout, "\" "); | |
1655 | @} | |
474c8240 | 1656 | @end smallexample |
0ee54786 EZ |
1657 | |
1658 | The following example from @code{print_one_breakpoint} shows how to | |
1659 | use @code{ui_out_field_int} and @code{ui_out_spaces}. The original | |
1660 | code was: | |
1661 | ||
474c8240 | 1662 | @smallexample |
0ee54786 EZ |
1663 | annotate_field (5); |
1664 | if (b->forked_inferior_pid != 0) | |
1665 | printf_filtered ("process %d ", b->forked_inferior_pid); | |
474c8240 | 1666 | @end smallexample |
0ee54786 EZ |
1667 | |
1668 | It became: | |
1669 | ||
474c8240 | 1670 | @smallexample |
0ee54786 EZ |
1671 | annotate_field (5); |
1672 | if (b->forked_inferior_pid != 0) | |
1673 | @{ | |
1674 | ui_out_text (uiout, "process "); | |
1675 | ui_out_field_int (uiout, "what", b->forked_inferior_pid); | |
1676 | ui_out_spaces (uiout, 1); | |
1677 | @} | |
474c8240 | 1678 | @end smallexample |
0ee54786 EZ |
1679 | |
1680 | Here's an example of using @code{ui_out_field_string}. The original | |
1681 | code was: | |
1682 | ||
474c8240 | 1683 | @smallexample |
0ee54786 EZ |
1684 | annotate_field (5); |
1685 | if (b->exec_pathname != NULL) | |
1686 | printf_filtered ("program \"%s\" ", b->exec_pathname); | |
474c8240 | 1687 | @end smallexample |
0ee54786 EZ |
1688 | |
1689 | It became: | |
1690 | ||
474c8240 | 1691 | @smallexample |
0ee54786 EZ |
1692 | annotate_field (5); |
1693 | if (b->exec_pathname != NULL) | |
1694 | @{ | |
1695 | ui_out_text (uiout, "program \""); | |
1696 | ui_out_field_string (uiout, "what", b->exec_pathname); | |
1697 | ui_out_text (uiout, "\" "); | |
1698 | @} | |
474c8240 | 1699 | @end smallexample |
0ee54786 EZ |
1700 | |
1701 | Finally, here's an example of printing an address. The original code: | |
1702 | ||
474c8240 | 1703 | @smallexample |
0ee54786 EZ |
1704 | annotate_field (4); |
1705 | printf_filtered ("%s ", | |
15a661f3 | 1706 | hex_string_custom ((unsigned long) b->address, 8)); |
474c8240 | 1707 | @end smallexample |
0ee54786 EZ |
1708 | |
1709 | It became: | |
1710 | ||
474c8240 | 1711 | @smallexample |
0ee54786 EZ |
1712 | annotate_field (4); |
1713 | ui_out_field_core_addr (uiout, "Address", b->address); | |
474c8240 | 1714 | @end smallexample |
0ee54786 EZ |
1715 | |
1716 | ||
c906108c SS |
1717 | @section Console Printing |
1718 | ||
1719 | @section TUI | |
1720 | ||
89437448 | 1721 | @node libgdb |
c906108c | 1722 | |
89437448 AC |
1723 | @chapter libgdb |
1724 | ||
1725 | @section libgdb 1.0 | |
1726 | @cindex @code{libgdb} | |
1727 | @code{libgdb} 1.0 was an abortive project of years ago. The theory was | |
1728 | to provide an API to @value{GDBN}'s functionality. | |
1729 | ||
1730 | @section libgdb 2.0 | |
56caf160 | 1731 | @cindex @code{libgdb} |
89437448 AC |
1732 | @code{libgdb} 2.0 is an ongoing effort to update @value{GDBN} so that is |
1733 | better able to support graphical and other environments. | |
1734 | ||
1735 | Since @code{libgdb} development is on-going, its architecture is still | |
1736 | evolving. The following components have so far been identified: | |
1737 | ||
1738 | @itemize @bullet | |
1739 | @item | |
1740 | Observer - @file{gdb-events.h}. | |
1741 | @item | |
1742 | Builder - @file{ui-out.h} | |
1743 | @item | |
1744 | Event Loop - @file{event-loop.h} | |
1745 | @item | |
1746 | Library - @file{gdb.h} | |
1747 | @end itemize | |
1748 | ||
1749 | The model that ties these components together is described below. | |
1750 | ||
1751 | @section The @code{libgdb} Model | |
1752 | ||
1753 | A client of @code{libgdb} interacts with the library in two ways. | |
1754 | ||
1755 | @itemize @bullet | |
1756 | @item | |
1757 | As an observer (using @file{gdb-events}) receiving notifications from | |
1758 | @code{libgdb} of any internal state changes (break point changes, run | |
1759 | state, etc). | |
1760 | @item | |
1761 | As a client querying @code{libgdb} (using the @file{ui-out} builder) to | |
1762 | obtain various status values from @value{GDBN}. | |
1763 | @end itemize | |
1764 | ||
c1468174 | 1765 | Since @code{libgdb} could have multiple clients (e.g., a GUI supporting |
89437448 AC |
1766 | the existing @value{GDBN} CLI), those clients must co-operate when |
1767 | controlling @code{libgdb}. In particular, a client must ensure that | |
1768 | @code{libgdb} is idle (i.e. no other client is using @code{libgdb}) | |
1769 | before responding to a @file{gdb-event} by making a query. | |
1770 | ||
1771 | @section CLI support | |
1772 | ||
1773 | At present @value{GDBN}'s CLI is very much entangled in with the core of | |
1774 | @code{libgdb}. Consequently, a client wishing to include the CLI in | |
1775 | their interface needs to carefully co-ordinate its own and the CLI's | |
1776 | requirements. | |
1777 | ||
1778 | It is suggested that the client set @code{libgdb} up to be bi-modal | |
1779 | (alternate between CLI and client query modes). The notes below sketch | |
1780 | out the theory: | |
1781 | ||
1782 | @itemize @bullet | |
1783 | @item | |
1784 | The client registers itself as an observer of @code{libgdb}. | |
1785 | @item | |
1786 | The client create and install @code{cli-out} builder using its own | |
1787 | versions of the @code{ui-file} @code{gdb_stderr}, @code{gdb_stdtarg} and | |
1788 | @code{gdb_stdout} streams. | |
1789 | @item | |
1790 | The client creates a separate custom @code{ui-out} builder that is only | |
1791 | used while making direct queries to @code{libgdb}. | |
1792 | @end itemize | |
1793 | ||
1794 | When the client receives input intended for the CLI, it simply passes it | |
1795 | along. Since the @code{cli-out} builder is installed by default, all | |
1796 | the CLI output in response to that command is routed (pronounced rooted) | |
1797 | through to the client controlled @code{gdb_stdout} et.@: al.@: streams. | |
1798 | At the same time, the client is kept abreast of internal changes by | |
1799 | virtue of being a @code{libgdb} observer. | |
1800 | ||
1801 | The only restriction on the client is that it must wait until | |
1802 | @code{libgdb} becomes idle before initiating any queries (using the | |
1803 | client's custom builder). | |
1804 | ||
1805 | @section @code{libgdb} components | |
1806 | ||
1807 | @subheading Observer - @file{gdb-events.h} | |
1808 | @file{gdb-events} provides the client with a very raw mechanism that can | |
1809 | be used to implement an observer. At present it only allows for one | |
1810 | observer and that observer must, internally, handle the need to delay | |
1811 | the processing of any event notifications until after @code{libgdb} has | |
1812 | finished the current command. | |
1813 | ||
1814 | @subheading Builder - @file{ui-out.h} | |
1815 | @file{ui-out} provides the infrastructure necessary for a client to | |
1816 | create a builder. That builder is then passed down to @code{libgdb} | |
1817 | when doing any queries. | |
1818 | ||
1819 | @subheading Event Loop - @file{event-loop.h} | |
1820 | @c There could be an entire section on the event-loop | |
1821 | @file{event-loop}, currently non-re-entrant, provides a simple event | |
1822 | loop. A client would need to either plug its self into this loop or, | |
1823 | implement a new event-loop that GDB would use. | |
1824 | ||
1825 | The event-loop will eventually be made re-entrant. This is so that | |
a9f12a31 | 1826 | @value{GDBN} can better handle the problem of some commands blocking |
89437448 AC |
1827 | instead of returning. |
1828 | ||
1829 | @subheading Library - @file{gdb.h} | |
1830 | @file{libgdb} is the most obvious component of this system. It provides | |
1831 | the query interface. Each function is parameterized by a @code{ui-out} | |
1832 | builder. The result of the query is constructed using that builder | |
1833 | before the query function returns. | |
c906108c | 1834 | |
5f5233d4 PA |
1835 | @node Values |
1836 | @chapter Values | |
1837 | @section Values | |
1838 | ||
1839 | @cindex values | |
1840 | @cindex @code{value} structure | |
1841 | @value{GDBN} uses @code{struct value}, or @dfn{values}, as an internal | |
1842 | abstraction for the representation of a variety of inferior objects | |
1843 | and @value{GDBN} convenience objects. | |
1844 | ||
1845 | Values have an associated @code{struct type}, that describes a virtual | |
1846 | view of the raw data or object stored in or accessed through the | |
1847 | value. | |
1848 | ||
1849 | A value is in addition discriminated by its lvalue-ness, given its | |
1850 | @code{enum lval_type} enumeration type: | |
1851 | ||
1852 | @cindex @code{lval_type} enumeration, for values. | |
1853 | @table @code | |
1854 | @item @code{not_lval} | |
1855 | This value is not an lval. It can't be assigned to. | |
1856 | ||
1857 | @item @code{lval_memory} | |
1858 | This value represents an object in memory. | |
1859 | ||
1860 | @item @code{lval_register} | |
1861 | This value represents an object that lives in a register. | |
1862 | ||
1863 | @item @code{lval_internalvar} | |
1864 | Represents the value of an internal variable. | |
1865 | ||
1866 | @item @code{lval_internalvar_component} | |
1867 | Represents part of a @value{GDBN} internal variable. E.g., a | |
1868 | structure field. | |
1869 | ||
1870 | @cindex computed values | |
1871 | @item @code{lval_computed} | |
1872 | These are ``computed'' values. They allow creating specialized value | |
1873 | objects for specific purposes, all abstracted away from the core value | |
1874 | support code. The creator of such a value writes specialized | |
1875 | functions to handle the reading and writing to/from the value's | |
1876 | backend data, and optionally, a ``copy operator'' and a | |
1877 | ``destructor''. | |
1878 | ||
1879 | Pointers to these functions are stored in a @code{struct lval_funcs} | |
1880 | instance (declared in @file{value.h}), and passed to the | |
1881 | @code{allocate_computed_value} function, as in the example below. | |
1882 | ||
1883 | @smallexample | |
1884 | static void | |
1885 | nil_value_read (struct value *v) | |
1886 | @{ | |
1887 | /* This callback reads data from some backend, and stores it in V. | |
1888 | In this case, we always read null data. You'll want to fill in | |
1889 | something more interesting. */ | |
1890 | ||
1891 | memset (value_contents_all_raw (v), | |
1892 | value_offset (v), | |
1893 | TYPE_LENGTH (value_type (v))); | |
1894 | @} | |
1895 | ||
1896 | static void | |
1897 | nil_value_write (struct value *v, struct value *fromval) | |
1898 | @{ | |
1899 | /* Takes the data from FROMVAL and stores it in the backend of V. */ | |
1900 | ||
1901 | to_oblivion (value_contents_all_raw (fromval), | |
1902 | value_offset (v), | |
1903 | TYPE_LENGTH (value_type (fromval))); | |
1904 | @} | |
1905 | ||
1906 | static struct lval_funcs nil_value_funcs = | |
1907 | @{ | |
1908 | nil_value_read, | |
1909 | nil_value_write | |
1910 | @}; | |
1911 | ||
1912 | struct value * | |
1913 | make_nil_value (void) | |
1914 | @{ | |
1915 | struct type *type; | |
1916 | struct value *v; | |
1917 | ||
1918 | type = make_nils_type (); | |
1919 | v = allocate_computed_value (type, &nil_value_funcs, NULL); | |
1920 | ||
1921 | return v; | |
1922 | @} | |
1923 | @end smallexample | |
1924 | ||
1925 | See the implementation of the @code{$_siginfo} convenience variable in | |
1926 | @file{infrun.c} as a real example use of lval_computed. | |
1927 | ||
1928 | @end table | |
1929 | ||
669fac23 DJ |
1930 | @node Stack Frames |
1931 | @chapter Stack Frames | |
1932 | ||
1933 | @cindex frame | |
1934 | @cindex call stack frame | |
1935 | A frame is a construct that @value{GDBN} uses to keep track of calling | |
1936 | and called functions. | |
1937 | ||
1938 | @cindex unwind frame | |
1939 | @value{GDBN}'s frame model, a fresh design, was implemented with the | |
1940 | need to support @sc{dwarf}'s Call Frame Information in mind. In fact, | |
1941 | the term ``unwind'' is taken directly from that specification. | |
1942 | Developers wishing to learn more about unwinders, are encouraged to | |
1943 | read the @sc{dwarf} specification, available from | |
1944 | @url{http://www.dwarfstd.org}. | |
1945 | ||
1946 | @findex frame_register_unwind | |
1947 | @findex get_frame_register | |
1948 | @value{GDBN}'s model is that you find a frame's registers by | |
1949 | ``unwinding'' them from the next younger frame. That is, | |
1950 | @samp{get_frame_register} which returns the value of a register in | |
1951 | frame #1 (the next-to-youngest frame), is implemented by calling frame | |
1952 | #0's @code{frame_register_unwind} (the youngest frame). But then the | |
1953 | obvious question is: how do you access the registers of the youngest | |
1954 | frame itself? | |
1955 | ||
1956 | @cindex sentinel frame | |
1957 | @findex get_frame_type | |
1958 | @vindex SENTINEL_FRAME | |
1959 | To answer this question, GDB has the @dfn{sentinel} frame, the | |
1960 | ``-1st'' frame. Unwinding registers from the sentinel frame gives you | |
1961 | the current values of the youngest real frame's registers. If @var{f} | |
1962 | is a sentinel frame, then @code{get_frame_type (@var{f}) @equiv{} | |
1963 | SENTINEL_FRAME}. | |
1964 | ||
1965 | @section Selecting an Unwinder | |
1966 | ||
1967 | @findex frame_unwind_prepend_unwinder | |
1968 | @findex frame_unwind_append_unwinder | |
1969 | The architecture registers a list of frame unwinders (@code{struct | |
1970 | frame_unwind}), using the functions | |
1971 | @code{frame_unwind_prepend_unwinder} and | |
1972 | @code{frame_unwind_append_unwinder}. Each unwinder includes a | |
1973 | sniffer. Whenever @value{GDBN} needs to unwind a frame (to fetch the | |
1974 | previous frame's registers or the current frame's ID), it calls | |
1975 | registered sniffers in order to find one which recognizes the frame. | |
1976 | The first time a sniffer returns non-zero, the corresponding unwinder | |
1977 | is assigned to the frame. | |
1978 | ||
1979 | @section Unwinding the Frame ID | |
1980 | @cindex frame ID | |
1981 | ||
1982 | Every frame has an associated ID, of type @code{struct frame_id}. | |
1983 | The ID includes the stack base and function start address for | |
1984 | the frame. The ID persists through the entire life of the frame, | |
1985 | including while other called frames are running; it is used to | |
1986 | locate an appropriate @code{struct frame_info} from the cache. | |
1987 | ||
1988 | Every time the inferior stops, and at various other times, the frame | |
1989 | cache is flushed. Because of this, parts of @value{GDBN} which need | |
1990 | to keep track of individual frames cannot use pointers to @code{struct | |
1991 | frame_info}. A frame ID provides a stable reference to a frame, even | |
1992 | when the unwinder must be run again to generate a new @code{struct | |
1993 | frame_info} for the same frame. | |
1994 | ||
1995 | The frame's unwinder's @code{this_id} method is called to find the ID. | |
1996 | Note that this is different from register unwinding, where the next | |
1997 | frame's @code{prev_register} is called to unwind this frame's | |
1998 | registers. | |
1999 | ||
2000 | Both stack base and function address are required to identify the | |
2001 | frame, because a recursive function has the same function address for | |
2002 | two consecutive frames and a leaf function may have the same stack | |
2003 | address as its caller. On some platforms, a third address is part of | |
2004 | the ID to further disambiguate frames---for instance, on IA-64 | |
2005 | the separate register stack address is included in the ID. | |
2006 | ||
2007 | An invalid frame ID (@code{null_frame_id}) returned from the | |
2008 | @code{this_id} method means to stop unwinding after this frame. | |
2009 | ||
2010 | @section Unwinding Registers | |
2011 | ||
2012 | Each unwinder includes a @code{prev_register} method. This method | |
2013 | takes a frame, an associated cache pointer, and a register number. | |
2014 | It returns a @code{struct value *} describing the requested register, | |
2015 | as saved by this frame. This is the value of the register that is | |
2016 | current in this frame's caller. | |
2017 | ||
2018 | The returned value must have the same type as the register. It may | |
2019 | have any lvalue type. In most circumstances one of these routines | |
2020 | will generate the appropriate value: | |
2021 | ||
2022 | @table @code | |
2023 | @item frame_unwind_got_optimized | |
2024 | @findex frame_unwind_got_optimized | |
2025 | This register was not saved. | |
2026 | ||
2027 | @item frame_unwind_got_register | |
2028 | @findex frame_unwind_got_register | |
2029 | This register was copied into another register in this frame. This | |
2030 | is also used for unchanged registers; they are ``copied'' into the | |
2031 | same register. | |
2032 | ||
2033 | @item frame_unwind_got_memory | |
2034 | @findex frame_unwind_got_memory | |
2035 | This register was saved in memory. | |
2036 | ||
2037 | @item frame_unwind_got_constant | |
2038 | @findex frame_unwind_got_constant | |
2039 | This register was not saved, but the unwinder can compute the previous | |
2040 | value some other way. | |
2041 | ||
2042 | @item frame_unwind_got_address | |
2043 | @findex frame_unwind_got_address | |
2044 | Same as @code{frame_unwind_got_constant}, except that the value is a target | |
2045 | address. This is frequently used for the stack pointer, which is not | |
2046 | explicitly saved but has a known offset from this frame's stack | |
2047 | pointer. For architectures with a flat unified address space, this is | |
2048 | generally the same as @code{frame_unwind_got_constant}. | |
2049 | @end table | |
2050 | ||
c906108c SS |
2051 | @node Symbol Handling |
2052 | ||
2053 | @chapter Symbol Handling | |
2054 | ||
1f70da6a SS |
2055 | Symbols are a key part of @value{GDBN}'s operation. Symbols include |
2056 | variables, functions, and types. | |
2057 | ||
2058 | Symbol information for a large program can be truly massive, and | |
2059 | reading of symbol information is one of the major performance | |
2060 | bottlenecks in @value{GDBN}; it can take many minutes to process it | |
2061 | all. Studies have shown that nearly all the time spent is | |
2062 | computational, rather than file reading. | |
2063 | ||
2064 | One of the ways for @value{GDBN} to provide a good user experience is | |
2065 | to start up quickly, taking no more than a few seconds. It is simply | |
2066 | not possible to process all of a program's debugging info in that | |
2067 | time, and so we attempt to handle symbols incrementally. For instance, | |
2068 | we create @dfn{partial symbol tables} consisting of only selected | |
2069 | symbols, and only expand them to full symbol tables when necessary. | |
c906108c SS |
2070 | |
2071 | @section Symbol Reading | |
2072 | ||
56caf160 EZ |
2073 | @cindex symbol reading |
2074 | @cindex reading of symbols | |
2075 | @cindex symbol files | |
2076 | @value{GDBN} reads symbols from @dfn{symbol files}. The usual symbol | |
2077 | file is the file containing the program which @value{GDBN} is | |
2078 | debugging. @value{GDBN} can be directed to use a different file for | |
2079 | symbols (with the @samp{symbol-file} command), and it can also read | |
1f70da6a SS |
2080 | more symbols via the @samp{add-file} and @samp{load} commands. In |
2081 | addition, it may bring in more symbols while loading shared | |
2082 | libraries. | |
56caf160 EZ |
2083 | |
2084 | @findex find_sym_fns | |
2085 | Symbol files are initially opened by code in @file{symfile.c} using | |
2086 | the BFD library (@pxref{Support Libraries}). BFD identifies the type | |
2087 | of the file by examining its header. @code{find_sym_fns} then uses | |
2088 | this identification to locate a set of symbol-reading functions. | |
2089 | ||
2090 | @findex add_symtab_fns | |
2091 | @cindex @code{sym_fns} structure | |
2092 | @cindex adding a symbol-reading module | |
2093 | Symbol-reading modules identify themselves to @value{GDBN} by calling | |
c906108c SS |
2094 | @code{add_symtab_fns} during their module initialization. The argument |
2095 | to @code{add_symtab_fns} is a @code{struct sym_fns} which contains the | |
2096 | name (or name prefix) of the symbol format, the length of the prefix, | |
2097 | and pointers to four functions. These functions are called at various | |
56caf160 | 2098 | times to process symbol files whose identification matches the specified |
c906108c SS |
2099 | prefix. |
2100 | ||
2101 | The functions supplied by each module are: | |
2102 | ||
2103 | @table @code | |
2104 | @item @var{xyz}_symfile_init(struct sym_fns *sf) | |
2105 | ||
56caf160 | 2106 | @cindex secondary symbol file |
c906108c SS |
2107 | Called from @code{symbol_file_add} when we are about to read a new |
2108 | symbol file. This function should clean up any internal state (possibly | |
2109 | resulting from half-read previous files, for example) and prepare to | |
56caf160 EZ |
2110 | read a new symbol file. Note that the symbol file which we are reading |
2111 | might be a new ``main'' symbol file, or might be a secondary symbol file | |
c906108c SS |
2112 | whose symbols are being added to the existing symbol table. |
2113 | ||
2114 | The argument to @code{@var{xyz}_symfile_init} is a newly allocated | |
2115 | @code{struct sym_fns} whose @code{bfd} field contains the BFD for the | |
2116 | new symbol file being read. Its @code{private} field has been zeroed, | |
2117 | and can be modified as desired. Typically, a struct of private | |
2118 | information will be @code{malloc}'d, and a pointer to it will be placed | |
2119 | in the @code{private} field. | |
2120 | ||
2121 | There is no result from @code{@var{xyz}_symfile_init}, but it can call | |
2122 | @code{error} if it detects an unavoidable problem. | |
2123 | ||
2124 | @item @var{xyz}_new_init() | |
2125 | ||
2126 | Called from @code{symbol_file_add} when discarding existing symbols. | |
56caf160 EZ |
2127 | This function needs only handle the symbol-reading module's internal |
2128 | state; the symbol table data structures visible to the rest of | |
2129 | @value{GDBN} will be discarded by @code{symbol_file_add}. It has no | |
2130 | arguments and no result. It may be called after | |
2131 | @code{@var{xyz}_symfile_init}, if a new symbol table is being read, or | |
2132 | may be called alone if all symbols are simply being discarded. | |
c906108c SS |
2133 | |
2134 | @item @var{xyz}_symfile_read(struct sym_fns *sf, CORE_ADDR addr, int mainline) | |
2135 | ||
2136 | Called from @code{symbol_file_add} to actually read the symbols from a | |
2137 | symbol-file into a set of psymtabs or symtabs. | |
2138 | ||
56caf160 | 2139 | @code{sf} points to the @code{struct sym_fns} originally passed to |
c906108c SS |
2140 | @code{@var{xyz}_sym_init} for possible initialization. @code{addr} is |
2141 | the offset between the file's specified start address and its true | |
2142 | address in memory. @code{mainline} is 1 if this is the main symbol | |
c1468174 | 2143 | table being read, and 0 if a secondary symbol file (e.g., shared library |
c906108c SS |
2144 | or dynamically loaded file) is being read.@refill |
2145 | @end table | |
2146 | ||
2147 | In addition, if a symbol-reading module creates psymtabs when | |
2148 | @var{xyz}_symfile_read is called, these psymtabs will contain a pointer | |
2149 | to a function @code{@var{xyz}_psymtab_to_symtab}, which can be called | |
25822942 | 2150 | from any point in the @value{GDBN} symbol-handling code. |
c906108c SS |
2151 | |
2152 | @table @code | |
2153 | @item @var{xyz}_psymtab_to_symtab (struct partial_symtab *pst) | |
2154 | ||
56caf160 | 2155 | Called from @code{psymtab_to_symtab} (or the @code{PSYMTAB_TO_SYMTAB} macro) if |
c906108c SS |
2156 | the psymtab has not already been read in and had its @code{pst->symtab} |
2157 | pointer set. The argument is the psymtab to be fleshed-out into a | |
56caf160 EZ |
2158 | symtab. Upon return, @code{pst->readin} should have been set to 1, and |
2159 | @code{pst->symtab} should contain a pointer to the new corresponding symtab, or | |
c906108c SS |
2160 | zero if there were no symbols in that part of the symbol file. |
2161 | @end table | |
2162 | ||
2163 | @section Partial Symbol Tables | |
2164 | ||
56caf160 | 2165 | @value{GDBN} has three types of symbol tables: |
c906108c SS |
2166 | |
2167 | @itemize @bullet | |
56caf160 EZ |
2168 | @cindex full symbol table |
2169 | @cindex symtabs | |
2170 | @item | |
2171 | Full symbol tables (@dfn{symtabs}). These contain the main | |
2172 | information about symbols and addresses. | |
c906108c | 2173 | |
56caf160 EZ |
2174 | @cindex psymtabs |
2175 | @item | |
2176 | Partial symbol tables (@dfn{psymtabs}). These contain enough | |
c906108c SS |
2177 | information to know when to read the corresponding part of the full |
2178 | symbol table. | |
2179 | ||
56caf160 EZ |
2180 | @cindex minimal symbol table |
2181 | @cindex minsymtabs | |
2182 | @item | |
2183 | Minimal symbol tables (@dfn{msymtabs}). These contain information | |
c906108c | 2184 | gleaned from non-debugging symbols. |
c906108c SS |
2185 | @end itemize |
2186 | ||
56caf160 | 2187 | @cindex partial symbol table |
c906108c SS |
2188 | This section describes partial symbol tables. |
2189 | ||
2190 | A psymtab is constructed by doing a very quick pass over an executable | |
2191 | file's debugging information. Small amounts of information are | |
56caf160 | 2192 | extracted---enough to identify which parts of the symbol table will |
c906108c | 2193 | need to be re-read and fully digested later, when the user needs the |
25822942 | 2194 | information. The speed of this pass causes @value{GDBN} to start up very |
c906108c SS |
2195 | quickly. Later, as the detailed rereading occurs, it occurs in small |
2196 | pieces, at various times, and the delay therefrom is mostly invisible to | |
2197 | the user. | |
2198 | @c (@xref{Symbol Reading}.) | |
2199 | ||
2200 | The symbols that show up in a file's psymtab should be, roughly, those | |
2201 | visible to the debugger's user when the program is not running code from | |
2202 | that file. These include external symbols and types, static symbols and | |
56caf160 | 2203 | types, and @code{enum} values declared at file scope. |
c906108c SS |
2204 | |
2205 | The psymtab also contains the range of instruction addresses that the | |
2206 | full symbol table would represent. | |
2207 | ||
56caf160 EZ |
2208 | @cindex finding a symbol |
2209 | @cindex symbol lookup | |
c906108c SS |
2210 | The idea is that there are only two ways for the user (or much of the |
2211 | code in the debugger) to reference a symbol: | |
2212 | ||
2213 | @itemize @bullet | |
56caf160 EZ |
2214 | @findex find_pc_function |
2215 | @findex find_pc_line | |
2216 | @item | |
c1468174 | 2217 | By its address (e.g., execution stops at some address which is inside a |
56caf160 EZ |
2218 | function in this file). The address will be noticed to be in the |
2219 | range of this psymtab, and the full symtab will be read in. | |
2220 | @code{find_pc_function}, @code{find_pc_line}, and other | |
2221 | @code{find_pc_@dots{}} functions handle this. | |
c906108c | 2222 | |
56caf160 EZ |
2223 | @cindex lookup_symbol |
2224 | @item | |
2225 | By its name | |
c1468174 | 2226 | (e.g., the user asks to print a variable, or set a breakpoint on a |
c906108c SS |
2227 | function). Global names and file-scope names will be found in the |
2228 | psymtab, which will cause the symtab to be pulled in. Local names will | |
2229 | have to be qualified by a global name, or a file-scope name, in which | |
2230 | case we will have already read in the symtab as we evaluated the | |
56caf160 | 2231 | qualifier. Or, a local symbol can be referenced when we are ``in'' a |
c906108c SS |
2232 | local scope, in which case the first case applies. @code{lookup_symbol} |
2233 | does most of the work here. | |
c906108c SS |
2234 | @end itemize |
2235 | ||
2236 | The only reason that psymtabs exist is to cause a symtab to be read in | |
2237 | at the right moment. Any symbol that can be elided from a psymtab, | |
2238 | while still causing that to happen, should not appear in it. Since | |
2239 | psymtabs don't have the idea of scope, you can't put local symbols in | |
2240 | them anyway. Psymtabs don't have the idea of the type of a symbol, | |
2241 | either, so types need not appear, unless they will be referenced by | |
2242 | name. | |
2243 | ||
56caf160 EZ |
2244 | It is a bug for @value{GDBN} to behave one way when only a psymtab has |
2245 | been read, and another way if the corresponding symtab has been read | |
2246 | in. Such bugs are typically caused by a psymtab that does not contain | |
2247 | all the visible symbols, or which has the wrong instruction address | |
2248 | ranges. | |
c906108c | 2249 | |
56caf160 | 2250 | The psymtab for a particular section of a symbol file (objfile) could be |
c906108c SS |
2251 | thrown away after the symtab has been read in. The symtab should always |
2252 | be searched before the psymtab, so the psymtab will never be used (in a | |
2253 | bug-free environment). Currently, psymtabs are allocated on an obstack, | |
2254 | and all the psymbols themselves are allocated in a pair of large arrays | |
2255 | on an obstack, so there is little to be gained by trying to free them | |
2256 | unless you want to do a lot more work. | |
2257 | ||
2258 | @section Types | |
2259 | ||
56caf160 | 2260 | @unnumberedsubsec Fundamental Types (e.g., @code{FT_VOID}, @code{FT_BOOLEAN}). |
c906108c | 2261 | |
56caf160 | 2262 | @cindex fundamental types |
25822942 | 2263 | These are the fundamental types that @value{GDBN} uses internally. Fundamental |
c906108c SS |
2264 | types from the various debugging formats (stabs, ELF, etc) are mapped |
2265 | into one of these. They are basically a union of all fundamental types | |
56caf160 EZ |
2266 | that @value{GDBN} knows about for all the languages that @value{GDBN} |
2267 | knows about. | |
c906108c | 2268 | |
56caf160 | 2269 | @unnumberedsubsec Type Codes (e.g., @code{TYPE_CODE_PTR}, @code{TYPE_CODE_ARRAY}). |
c906108c | 2270 | |
56caf160 EZ |
2271 | @cindex type codes |
2272 | Each time @value{GDBN} builds an internal type, it marks it with one | |
2273 | of these types. The type may be a fundamental type, such as | |
2274 | @code{TYPE_CODE_INT}, or a derived type, such as @code{TYPE_CODE_PTR} | |
2275 | which is a pointer to another type. Typically, several @code{FT_*} | |
2276 | types map to one @code{TYPE_CODE_*} type, and are distinguished by | |
2277 | other members of the type struct, such as whether the type is signed | |
2278 | or unsigned, and how many bits it uses. | |
c906108c | 2279 | |
56caf160 | 2280 | @unnumberedsubsec Builtin Types (e.g., @code{builtin_type_void}, @code{builtin_type_char}). |
c906108c SS |
2281 | |
2282 | These are instances of type structs that roughly correspond to | |
56caf160 EZ |
2283 | fundamental types and are created as global types for @value{GDBN} to |
2284 | use for various ugly historical reasons. We eventually want to | |
2285 | eliminate these. Note for example that @code{builtin_type_int} | |
2286 | initialized in @file{gdbtypes.c} is basically the same as a | |
2287 | @code{TYPE_CODE_INT} type that is initialized in @file{c-lang.c} for | |
2288 | an @code{FT_INTEGER} fundamental type. The difference is that the | |
2289 | @code{builtin_type} is not associated with any particular objfile, and | |
2290 | only one instance exists, while @file{c-lang.c} builds as many | |
2291 | @code{TYPE_CODE_INT} types as needed, with each one associated with | |
2292 | some particular objfile. | |
c906108c SS |
2293 | |
2294 | @section Object File Formats | |
56caf160 | 2295 | @cindex object file formats |
c906108c SS |
2296 | |
2297 | @subsection a.out | |
2298 | ||
56caf160 EZ |
2299 | @cindex @code{a.out} format |
2300 | The @code{a.out} format is the original file format for Unix. It | |
2301 | consists of three sections: @code{text}, @code{data}, and @code{bss}, | |
2302 | which are for program code, initialized data, and uninitialized data, | |
2303 | respectively. | |
c906108c | 2304 | |
56caf160 | 2305 | The @code{a.out} format is so simple that it doesn't have any reserved |
c906108c | 2306 | place for debugging information. (Hey, the original Unix hackers used |
56caf160 EZ |
2307 | @samp{adb}, which is a machine-language debugger!) The only debugging |
2308 | format for @code{a.out} is stabs, which is encoded as a set of normal | |
c906108c SS |
2309 | symbols with distinctive attributes. |
2310 | ||
56caf160 | 2311 | The basic @code{a.out} reader is in @file{dbxread.c}. |
c906108c SS |
2312 | |
2313 | @subsection COFF | |
2314 | ||
56caf160 | 2315 | @cindex COFF format |
c906108c SS |
2316 | The COFF format was introduced with System V Release 3 (SVR3) Unix. |
2317 | COFF files may have multiple sections, each prefixed by a header. The | |
2318 | number of sections is limited. | |
2319 | ||
2320 | The COFF specification includes support for debugging. Although this | |
1f70da6a SS |
2321 | was a step forward, the debugging information was woefully limited. |
2322 | For instance, it was not possible to represent code that came from an | |
2323 | included file. GNU's COFF-using configs often use stabs-type info, | |
2324 | encapsulated in special sections. | |
c906108c SS |
2325 | |
2326 | The COFF reader is in @file{coffread.c}. | |
2327 | ||
2328 | @subsection ECOFF | |
2329 | ||
56caf160 | 2330 | @cindex ECOFF format |
c906108c SS |
2331 | ECOFF is an extended COFF originally introduced for Mips and Alpha |
2332 | workstations. | |
2333 | ||
2334 | The basic ECOFF reader is in @file{mipsread.c}. | |
2335 | ||
2336 | @subsection XCOFF | |
2337 | ||
56caf160 | 2338 | @cindex XCOFF format |
c906108c SS |
2339 | The IBM RS/6000 running AIX uses an object file format called XCOFF. |
2340 | The COFF sections, symbols, and line numbers are used, but debugging | |
56caf160 EZ |
2341 | symbols are @code{dbx}-style stabs whose strings are located in the |
2342 | @code{.debug} section (rather than the string table). For more | |
2343 | information, see @ref{Top,,,stabs,The Stabs Debugging Format}. | |
c906108c SS |
2344 | |
2345 | The shared library scheme has a clean interface for figuring out what | |
2346 | shared libraries are in use, but the catch is that everything which | |
2347 | refers to addresses (symbol tables and breakpoints at least) needs to be | |
2348 | relocated for both shared libraries and the main executable. At least | |
2349 | using the standard mechanism this can only be done once the program has | |
2350 | been run (or the core file has been read). | |
2351 | ||
2352 | @subsection PE | |
2353 | ||
56caf160 EZ |
2354 | @cindex PE-COFF format |
2355 | Windows 95 and NT use the PE (@dfn{Portable Executable}) format for their | |
c906108c SS |
2356 | executables. PE is basically COFF with additional headers. |
2357 | ||
25822942 | 2358 | While BFD includes special PE support, @value{GDBN} needs only the basic |
c906108c SS |
2359 | COFF reader. |
2360 | ||
2361 | @subsection ELF | |
2362 | ||
56caf160 | 2363 | @cindex ELF format |
1f70da6a SS |
2364 | The ELF format came with System V Release 4 (SVR4) Unix. ELF is |
2365 | similar to COFF in being organized into a number of sections, but it | |
2366 | removes many of COFF's limitations. Debugging info may be either stabs | |
2367 | encapsulated in ELF sections, or more commonly these days, DWARF. | |
c906108c SS |
2368 | |
2369 | The basic ELF reader is in @file{elfread.c}. | |
2370 | ||
2371 | @subsection SOM | |
2372 | ||
56caf160 | 2373 | @cindex SOM format |
c906108c SS |
2374 | SOM is HP's object file and debug format (not to be confused with IBM's |
2375 | SOM, which is a cross-language ABI). | |
2376 | ||
1a92f856 | 2377 | The SOM reader is in @file{somread.c}. |
c906108c | 2378 | |
c906108c SS |
2379 | @section Debugging File Formats |
2380 | ||
2381 | This section describes characteristics of debugging information that | |
2382 | are independent of the object file format. | |
2383 | ||
2384 | @subsection stabs | |
2385 | ||
56caf160 | 2386 | @cindex stabs debugging info |
c906108c SS |
2387 | @code{stabs} started out as special symbols within the @code{a.out} |
2388 | format. Since then, it has been encapsulated into other file | |
2389 | formats, such as COFF and ELF. | |
2390 | ||
2391 | While @file{dbxread.c} does some of the basic stab processing, | |
2392 | including for encapsulated versions, @file{stabsread.c} does | |
2393 | the real work. | |
2394 | ||
2395 | @subsection COFF | |
2396 | ||
56caf160 | 2397 | @cindex COFF debugging info |
c906108c SS |
2398 | The basic COFF definition includes debugging information. The level |
2399 | of support is minimal and non-extensible, and is not often used. | |
2400 | ||
2401 | @subsection Mips debug (Third Eye) | |
2402 | ||
56caf160 | 2403 | @cindex ECOFF debugging info |
c906108c SS |
2404 | ECOFF includes a definition of a special debug format. |
2405 | ||
2406 | The file @file{mdebugread.c} implements reading for this format. | |
2407 | ||
1f70da6a SS |
2408 | @c mention DWARF 1 as a formerly-supported format |
2409 | ||
c906108c SS |
2410 | @subsection DWARF 2 |
2411 | ||
56caf160 | 2412 | @cindex DWARF 2 debugging info |
c906108c SS |
2413 | DWARF 2 is an improved but incompatible version of DWARF 1. |
2414 | ||
2415 | The DWARF 2 reader is in @file{dwarf2read.c}. | |
2416 | ||
31fffb02 CS |
2417 | @subsection Compressed DWARF 2 |
2418 | ||
2419 | @cindex Compressed DWARF 2 debugging info | |
2420 | Compressed DWARF 2 is not technically a separate debugging format, but | |
2421 | merely DWARF 2 debug information that has been compressed. In this | |
2422 | format, every object-file section holding DWARF 2 debugging | |
2423 | information is compressed and prepended with a header. (The section | |
2424 | is also typically renamed, so a section called @code{.debug_info} in a | |
2425 | DWARF 2 binary would be called @code{.zdebug_info} in a compressed | |
2426 | DWARF 2 binary.) The header is 12 bytes long: | |
2427 | ||
2428 | @itemize @bullet | |
2429 | @item | |
2430 | 4 bytes: the literal string ``ZLIB'' | |
2431 | @item | |
2432 | 8 bytes: the uncompressed size of the section, in big-endian byte | |
2433 | order. | |
2434 | @end itemize | |
2435 | ||
2436 | The same reader is used for both compressed an normal DWARF 2 info. | |
2437 | Section decompression is done in @code{zlib_decompress_section} in | |
2438 | @file{dwarf2read.c}. | |
2439 | ||
1f70da6a SS |
2440 | @subsection DWARF 3 |
2441 | ||
2442 | @cindex DWARF 3 debugging info | |
2443 | DWARF 3 is an improved version of DWARF 2. | |
2444 | ||
c906108c SS |
2445 | @subsection SOM |
2446 | ||
56caf160 | 2447 | @cindex SOM debugging info |
c906108c SS |
2448 | Like COFF, the SOM definition includes debugging information. |
2449 | ||
25822942 | 2450 | @section Adding a New Symbol Reader to @value{GDBN} |
c906108c | 2451 | |
56caf160 EZ |
2452 | @cindex adding debugging info reader |
2453 | If you are using an existing object file format (@code{a.out}, COFF, ELF, etc), | |
c906108c SS |
2454 | there is probably little to be done. |
2455 | ||
2456 | If you need to add a new object file format, you must first add it to | |
2457 | BFD. This is beyond the scope of this document. | |
2458 | ||
2459 | You must then arrange for the BFD code to provide access to the | |
1f70da6a SS |
2460 | debugging symbols. Generally @value{GDBN} will have to call swapping |
2461 | routines from BFD and a few other BFD internal routines to locate the | |
2462 | debugging information. As much as possible, @value{GDBN} should not | |
2463 | depend on the BFD internal data structures. | |
c906108c SS |
2464 | |
2465 | For some targets (e.g., COFF), there is a special transfer vector used | |
2466 | to call swapping routines, since the external data structures on various | |
2467 | platforms have different sizes and layouts. Specialized routines that | |
2468 | will only ever be implemented by one object file format may be called | |
2469 | directly. This interface should be described in a file | |
56caf160 | 2470 | @file{bfd/lib@var{xyz}.h}, which is included by @value{GDBN}. |
c906108c | 2471 | |
c91d38aa DJ |
2472 | @section Memory Management for Symbol Files |
2473 | ||
2474 | Most memory associated with a loaded symbol file is stored on | |
2475 | its @code{objfile_obstack}. This includes symbols, types, | |
2476 | namespace data, and other information produced by the symbol readers. | |
2477 | ||
2478 | Because this data lives on the objfile's obstack, it is automatically | |
2479 | released when the objfile is unloaded or reloaded. Therefore one | |
2480 | objfile must not reference symbol or type data from another objfile; | |
2481 | they could be unloaded at different times. | |
2482 | ||
2483 | User convenience variables, et cetera, have associated types. Normally | |
2484 | these types live in the associated objfile. However, when the objfile | |
2485 | is unloaded, those types are deep copied to global memory, so that | |
2486 | the values of the user variables and history items are not lost. | |
2487 | ||
c906108c SS |
2488 | |
2489 | @node Language Support | |
2490 | ||
2491 | @chapter Language Support | |
2492 | ||
56caf160 EZ |
2493 | @cindex language support |
2494 | @value{GDBN}'s language support is mainly driven by the symbol reader, | |
2495 | although it is possible for the user to set the source language | |
2496 | manually. | |
c906108c | 2497 | |
56caf160 EZ |
2498 | @value{GDBN} chooses the source language by looking at the extension |
2499 | of the file recorded in the debug info; @file{.c} means C, @file{.f} | |
2500 | means Fortran, etc. It may also use a special-purpose language | |
2501 | identifier if the debug format supports it, like with DWARF. | |
c906108c | 2502 | |
25822942 | 2503 | @section Adding a Source Language to @value{GDBN} |
c906108c | 2504 | |
56caf160 EZ |
2505 | @cindex adding source language |
2506 | To add other languages to @value{GDBN}'s expression parser, follow the | |
2507 | following steps: | |
c906108c SS |
2508 | |
2509 | @table @emph | |
2510 | @item Create the expression parser. | |
2511 | ||
56caf160 | 2512 | @cindex expression parser |
c906108c | 2513 | This should reside in a file @file{@var{lang}-exp.y}. Routines for |
56caf160 | 2514 | building parsed expressions into a @code{union exp_element} list are in |
c906108c SS |
2515 | @file{parse.c}. |
2516 | ||
56caf160 | 2517 | @cindex language parser |
c906108c SS |
2518 | Since we can't depend upon everyone having Bison, and YACC produces |
2519 | parsers that define a bunch of global names, the following lines | |
56caf160 | 2520 | @strong{must} be included at the top of the YACC parser, to prevent the |
c906108c SS |
2521 | various parsers from defining the same global names: |
2522 | ||
474c8240 | 2523 | @smallexample |
56caf160 EZ |
2524 | #define yyparse @var{lang}_parse |
2525 | #define yylex @var{lang}_lex | |
2526 | #define yyerror @var{lang}_error | |
2527 | #define yylval @var{lang}_lval | |
2528 | #define yychar @var{lang}_char | |
2529 | #define yydebug @var{lang}_debug | |
2530 | #define yypact @var{lang}_pact | |
2531 | #define yyr1 @var{lang}_r1 | |
2532 | #define yyr2 @var{lang}_r2 | |
2533 | #define yydef @var{lang}_def | |
2534 | #define yychk @var{lang}_chk | |
2535 | #define yypgo @var{lang}_pgo | |
2536 | #define yyact @var{lang}_act | |
2537 | #define yyexca @var{lang}_exca | |
2538 | #define yyerrflag @var{lang}_errflag | |
2539 | #define yynerrs @var{lang}_nerrs | |
474c8240 | 2540 | @end smallexample |
c906108c SS |
2541 | |
2542 | At the bottom of your parser, define a @code{struct language_defn} and | |
2543 | initialize it with the right values for your language. Define an | |
2544 | @code{initialize_@var{lang}} routine and have it call | |
25822942 | 2545 | @samp{add_language(@var{lang}_language_defn)} to tell the rest of @value{GDBN} |
c906108c SS |
2546 | that your language exists. You'll need some other supporting variables |
2547 | and functions, which will be used via pointers from your | |
2548 | @code{@var{lang}_language_defn}. See the declaration of @code{struct | |
2549 | language_defn} in @file{language.h}, and the other @file{*-exp.y} files, | |
2550 | for more information. | |
2551 | ||
2552 | @item Add any evaluation routines, if necessary | |
2553 | ||
56caf160 EZ |
2554 | @cindex expression evaluation routines |
2555 | @findex evaluate_subexp | |
2556 | @findex prefixify_subexp | |
2557 | @findex length_of_subexp | |
c906108c SS |
2558 | If you need new opcodes (that represent the operations of the language), |
2559 | add them to the enumerated type in @file{expression.h}. Add support | |
56caf160 EZ |
2560 | code for these operations in the @code{evaluate_subexp} function |
2561 | defined in the file @file{eval.c}. Add cases | |
c906108c | 2562 | for new opcodes in two functions from @file{parse.c}: |
56caf160 | 2563 | @code{prefixify_subexp} and @code{length_of_subexp}. These compute |
c906108c SS |
2564 | the number of @code{exp_element}s that a given operation takes up. |
2565 | ||
2566 | @item Update some existing code | |
2567 | ||
2568 | Add an enumerated identifier for your language to the enumerated type | |
2569 | @code{enum language} in @file{defs.h}. | |
2570 | ||
2571 | Update the routines in @file{language.c} so your language is included. | |
2572 | These routines include type predicates and such, which (in some cases) | |
2573 | are language dependent. If your language does not appear in the switch | |
2574 | statement, an error is reported. | |
2575 | ||
56caf160 | 2576 | @vindex current_language |
c906108c SS |
2577 | Also included in @file{language.c} is the code that updates the variable |
2578 | @code{current_language}, and the routines that translate the | |
2579 | @code{language_@var{lang}} enumerated identifier into a printable | |
2580 | string. | |
2581 | ||
56caf160 | 2582 | @findex _initialize_language |
c906108c SS |
2583 | Update the function @code{_initialize_language} to include your |
2584 | language. This function picks the default language upon startup, so is | |
25822942 | 2585 | dependent upon which languages that @value{GDBN} is built for. |
c906108c | 2586 | |
56caf160 | 2587 | @findex allocate_symtab |
c906108c SS |
2588 | Update @code{allocate_symtab} in @file{symfile.c} and/or symbol-reading |
2589 | code so that the language of each symtab (source file) is set properly. | |
2590 | This is used to determine the language to use at each stack frame level. | |
2591 | Currently, the language is set based upon the extension of the source | |
2592 | file. If the language can be better inferred from the symbol | |
2593 | information, please set the language of the symtab in the symbol-reading | |
2594 | code. | |
2595 | ||
56caf160 EZ |
2596 | @findex print_subexp |
2597 | @findex op_print_tab | |
2598 | Add helper code to @code{print_subexp} (in @file{expprint.c}) to handle any new | |
c906108c SS |
2599 | expression opcodes you have added to @file{expression.h}. Also, add the |
2600 | printed representations of your operators to @code{op_print_tab}. | |
2601 | ||
2602 | @item Add a place of call | |
2603 | ||
56caf160 | 2604 | @findex parse_exp_1 |
c906108c | 2605 | Add a call to @code{@var{lang}_parse()} and @code{@var{lang}_error} in |
56caf160 | 2606 | @code{parse_exp_1} (defined in @file{parse.c}). |
c906108c | 2607 | |
c906108c SS |
2608 | @item Edit @file{Makefile.in} |
2609 | ||
2610 | Add dependencies in @file{Makefile.in}. Make sure you update the macro | |
2611 | variables such as @code{HFILES} and @code{OBJS}, otherwise your code may | |
2612 | not get linked in, or, worse yet, it may not get @code{tar}red into the | |
2613 | distribution! | |
c906108c SS |
2614 | @end table |
2615 | ||
2616 | ||
2617 | @node Host Definition | |
2618 | ||
2619 | @chapter Host Definition | |
2620 | ||
56caf160 | 2621 | With the advent of Autoconf, it's rarely necessary to have host |
7fd60527 AC |
2622 | definition machinery anymore. The following information is provided, |
2623 | mainly, as an historical reference. | |
c906108c SS |
2624 | |
2625 | @section Adding a New Host | |
2626 | ||
56caf160 EZ |
2627 | @cindex adding a new host |
2628 | @cindex host, adding | |
7fd60527 AC |
2629 | @value{GDBN}'s host configuration support normally happens via Autoconf. |
2630 | New host-specific definitions should not be needed. Older hosts | |
2631 | @value{GDBN} still use the host-specific definitions and files listed | |
2632 | below, but these mostly exist for historical reasons, and will | |
56caf160 | 2633 | eventually disappear. |
c906108c | 2634 | |
c906108c | 2635 | @table @file |
c906108c | 2636 | @item gdb/config/@var{arch}/@var{xyz}.mh |
1f70da6a SS |
2637 | This file is a Makefile fragment that once contained both host and |
2638 | native configuration information (@pxref{Native Debugging}) for the | |
2639 | machine @var{xyz}. The host configuration information is now handled | |
2640 | by Autoconf. | |
7fd60527 | 2641 | |
1f70da6a | 2642 | Host configuration information included definitions for @code{CC}, |
7708fa01 AC |
2643 | @code{SYSV_DEFINE}, @code{XM_CFLAGS}, @code{XM_ADD_FILES}, |
2644 | @code{XM_CLIBS}, @code{XM_CDEPS}, etc.; see @file{Makefile.in}. | |
c906108c | 2645 | |
1f70da6a | 2646 | New host-only configurations do not need this file. |
c906108c | 2647 | |
c906108c SS |
2648 | @end table |
2649 | ||
1f70da6a SS |
2650 | (Files named @file{gdb/config/@var{arch}/xm-@var{xyz}.h} were once |
2651 | used to define host-specific macros, but were no longer needed and | |
2652 | have all been removed.) | |
2653 | ||
c906108c SS |
2654 | @subheading Generic Host Support Files |
2655 | ||
56caf160 | 2656 | @cindex generic host support |
c906108c | 2657 | There are some ``generic'' versions of routines that can be used by |
1f70da6a | 2658 | various systems. |
c906108c SS |
2659 | |
2660 | @table @file | |
56caf160 EZ |
2661 | @cindex remote debugging support |
2662 | @cindex serial line support | |
c906108c | 2663 | @item ser-unix.c |
1f70da6a SS |
2664 | This contains serial line support for Unix systems. It is included by |
2665 | default on all Unix-like hosts. | |
2666 | ||
2667 | @item ser-pipe.c | |
2668 | This contains serial pipe support for Unix systems. It is included by | |
2669 | default on all Unix-like hosts. | |
2670 | ||
2671 | @item ser-mingw.c | |
2672 | This contains serial line support for 32-bit programs running under | |
2673 | Windows using MinGW. | |
c906108c SS |
2674 | |
2675 | @item ser-go32.c | |
2676 | This contains serial line support for 32-bit programs running under DOS, | |
56caf160 | 2677 | using the DJGPP (a.k.a.@: GO32) execution environment. |
c906108c | 2678 | |
56caf160 | 2679 | @cindex TCP remote support |
c906108c | 2680 | @item ser-tcp.c |
1f70da6a SS |
2681 | This contains generic TCP support using sockets. It is included by |
2682 | default on all Unix-like hosts and with MinGW. | |
c906108c SS |
2683 | @end table |
2684 | ||
2685 | @section Host Conditionals | |
2686 | ||
56caf160 EZ |
2687 | When @value{GDBN} is configured and compiled, various macros are |
2688 | defined or left undefined, to control compilation based on the | |
1f70da6a SS |
2689 | attributes of the host system. While formerly they could be set in |
2690 | host-specific header files, at present they can be changed only by | |
2691 | setting @code{CFLAGS} when building, or by editing the source code. | |
2692 | ||
2693 | These macros and their meanings (or if the meaning is not documented | |
2694 | here, then one of the source files where they are used is indicated) | |
2695 | are: | |
c906108c | 2696 | |
56caf160 | 2697 | @ftable @code |
25822942 | 2698 | @item @value{GDBN}INIT_FILENAME |
56caf160 EZ |
2699 | The default name of @value{GDBN}'s initialization file (normally |
2700 | @file{.gdbinit}). | |
c906108c | 2701 | |
c906108c SS |
2702 | @item SIGWINCH_HANDLER |
2703 | If your host defines @code{SIGWINCH}, you can define this to be the name | |
2704 | of a function to be called if @code{SIGWINCH} is received. | |
2705 | ||
2706 | @item SIGWINCH_HANDLER_BODY | |
2707 | Define this to expand into code that will define the function named by | |
2708 | the expansion of @code{SIGWINCH_HANDLER}. | |
2709 | ||
c906108c | 2710 | @item CRLF_SOURCE_FILES |
56caf160 | 2711 | @cindex DOS text files |
c906108c SS |
2712 | Define this if host files use @code{\r\n} rather than @code{\n} as a |
2713 | line terminator. This will cause source file listings to omit @code{\r} | |
56caf160 EZ |
2714 | characters when printing and it will allow @code{\r\n} line endings of files |
2715 | which are ``sourced'' by gdb. It must be possible to open files in binary | |
c906108c SS |
2716 | mode using @code{O_BINARY} or, for fopen, @code{"rb"}. |
2717 | ||
2718 | @item DEFAULT_PROMPT | |
56caf160 | 2719 | @cindex prompt |
c906108c SS |
2720 | The default value of the prompt string (normally @code{"(gdb) "}). |
2721 | ||
2722 | @item DEV_TTY | |
56caf160 | 2723 | @cindex terminal device |
c906108c SS |
2724 | The name of the generic TTY device, defaults to @code{"/dev/tty"}. |
2725 | ||
c906108c SS |
2726 | @item ISATTY |
2727 | Substitute for isatty, if not available. | |
2728 | ||
1f70da6a SS |
2729 | @item FOPEN_RB |
2730 | Define this if binary files are opened the same way as text files. | |
c906108c SS |
2731 | |
2732 | @item CC_HAS_LONG_LONG | |
56caf160 EZ |
2733 | @cindex @code{long long} data type |
2734 | Define this if the host C compiler supports @code{long long}. This is set | |
2735 | by the @code{configure} script. | |
c906108c SS |
2736 | |
2737 | @item PRINTF_HAS_LONG_LONG | |
2738 | Define this if the host can handle printing of long long integers via | |
56caf160 EZ |
2739 | the printf format conversion specifier @code{ll}. This is set by the |
2740 | @code{configure} script. | |
c906108c | 2741 | |
c906108c SS |
2742 | @item LSEEK_NOT_LINEAR |
2743 | Define this if @code{lseek (n)} does not necessarily move to byte number | |
2744 | @code{n} in the file. This is only used when reading source files. It | |
2745 | is normally faster to define @code{CRLF_SOURCE_FILES} when possible. | |
2746 | ||
c906108c SS |
2747 | @item NORETURN |
2748 | If defined, this should be one or more tokens, such as @code{volatile}, | |
2749 | that can be used in both the declaration and definition of functions to | |
2750 | indicate that they never return. The default is already set correctly | |
2751 | if compiling with GCC. This will almost never need to be defined. | |
2752 | ||
2753 | @item ATTR_NORETURN | |
2754 | If defined, this should be one or more tokens, such as | |
2755 | @code{__attribute__ ((noreturn))}, that can be used in the declarations | |
2756 | of functions to indicate that they never return. The default is already | |
2757 | set correctly if compiling with GCC. This will almost never need to be | |
2758 | defined. | |
2759 | ||
c906108c | 2760 | @item lint |
56caf160 | 2761 | Define this to help placate @code{lint} in some situations. |
c906108c SS |
2762 | |
2763 | @item volatile | |
2764 | Define this to override the defaults of @code{__volatile__} or | |
2765 | @code{/**/}. | |
56caf160 | 2766 | @end ftable |
c906108c SS |
2767 | |
2768 | ||
2769 | @node Target Architecture Definition | |
2770 | ||
2771 | @chapter Target Architecture Definition | |
2772 | ||
56caf160 EZ |
2773 | @cindex target architecture definition |
2774 | @value{GDBN}'s target architecture defines what sort of | |
2775 | machine-language programs @value{GDBN} can work with, and how it works | |
2776 | with them. | |
c906108c | 2777 | |
af6c57ea AC |
2778 | The target architecture object is implemented as the C structure |
2779 | @code{struct gdbarch *}. The structure, and its methods, are generated | |
93c2c750 | 2780 | using the Bourne shell script @file{gdbarch.sh}. |
c906108c | 2781 | |
b6fd0dfb NR |
2782 | @menu |
2783 | * OS ABI Variant Handling:: | |
2784 | * Initialize New Architecture:: | |
2785 | * Registers and Memory:: | |
2786 | * Pointers and Addresses:: | |
2787 | * Address Classes:: | |
2788 | * Raw and Virtual Registers:: | |
2789 | * Register and Memory Data:: | |
2790 | * Frame Interpretation:: | |
2791 | * Inferior Call Setup:: | |
2792 | * Compiler Characteristics:: | |
2793 | * Target Conditionals:: | |
2794 | * Adding a New Target:: | |
b6fd0dfb NR |
2795 | @end menu |
2796 | ||
2797 | @node OS ABI Variant Handling | |
70f80edf JT |
2798 | @section Operating System ABI Variant Handling |
2799 | @cindex OS ABI variants | |
2800 | ||
2801 | @value{GDBN} provides a mechanism for handling variations in OS | |
2802 | ABIs. An OS ABI variant may have influence over any number of | |
2803 | variables in the target architecture definition. There are two major | |
2804 | components in the OS ABI mechanism: sniffers and handlers. | |
2805 | ||
2806 | A @dfn{sniffer} examines a file matching a BFD architecture/flavour pair | |
2807 | (the architecture may be wildcarded) in an attempt to determine the | |
2808 | OS ABI of that file. Sniffers with a wildcarded architecture are considered | |
2809 | to be @dfn{generic}, while sniffers for a specific architecture are | |
2810 | considered to be @dfn{specific}. A match from a specific sniffer | |
2811 | overrides a match from a generic sniffer. Multiple sniffers for an | |
2812 | architecture/flavour may exist, in order to differentiate between two | |
2813 | different operating systems which use the same basic file format. The | |
2814 | OS ABI framework provides a generic sniffer for ELF-format files which | |
2815 | examines the @code{EI_OSABI} field of the ELF header, as well as note | |
2816 | sections known to be used by several operating systems. | |
2817 | ||
2818 | @cindex fine-tuning @code{gdbarch} structure | |
2819 | A @dfn{handler} is used to fine-tune the @code{gdbarch} structure for the | |
2820 | selected OS ABI. There may be only one handler for a given OS ABI | |
2821 | for each BFD architecture. | |
2822 | ||
f4b3909f | 2823 | The following OS ABI variants are defined in @file{defs.h}: |
70f80edf JT |
2824 | |
2825 | @table @code | |
2826 | ||
f4b3909f EZ |
2827 | @findex GDB_OSABI_UNINITIALIZED |
2828 | @item GDB_OSABI_UNINITIALIZED | |
2829 | Used for struct gdbarch_info if ABI is still uninitialized. | |
2830 | ||
70f80edf JT |
2831 | @findex GDB_OSABI_UNKNOWN |
2832 | @item GDB_OSABI_UNKNOWN | |
2833 | The ABI of the inferior is unknown. The default @code{gdbarch} | |
2834 | settings for the architecture will be used. | |
2835 | ||
2836 | @findex GDB_OSABI_SVR4 | |
2837 | @item GDB_OSABI_SVR4 | |
f4b3909f | 2838 | UNIX System V Release 4. |
70f80edf JT |
2839 | |
2840 | @findex GDB_OSABI_HURD | |
2841 | @item GDB_OSABI_HURD | |
f4b3909f | 2842 | GNU using the Hurd kernel. |
70f80edf JT |
2843 | |
2844 | @findex GDB_OSABI_SOLARIS | |
2845 | @item GDB_OSABI_SOLARIS | |
f4b3909f | 2846 | Sun Solaris. |
70f80edf JT |
2847 | |
2848 | @findex GDB_OSABI_OSF1 | |
2849 | @item GDB_OSABI_OSF1 | |
f4b3909f | 2850 | OSF/1, including Digital UNIX and Compaq Tru64 UNIX. |
70f80edf JT |
2851 | |
2852 | @findex GDB_OSABI_LINUX | |
2853 | @item GDB_OSABI_LINUX | |
f4b3909f | 2854 | GNU using the Linux kernel. |
70f80edf JT |
2855 | |
2856 | @findex GDB_OSABI_FREEBSD_AOUT | |
2857 | @item GDB_OSABI_FREEBSD_AOUT | |
f4b3909f | 2858 | FreeBSD using the @code{a.out} executable format. |
70f80edf JT |
2859 | |
2860 | @findex GDB_OSABI_FREEBSD_ELF | |
2861 | @item GDB_OSABI_FREEBSD_ELF | |
f4b3909f | 2862 | FreeBSD using the ELF executable format. |
70f80edf JT |
2863 | |
2864 | @findex GDB_OSABI_NETBSD_AOUT | |
2865 | @item GDB_OSABI_NETBSD_AOUT | |
f4b3909f | 2866 | NetBSD using the @code{a.out} executable format. |
70f80edf JT |
2867 | |
2868 | @findex GDB_OSABI_NETBSD_ELF | |
2869 | @item GDB_OSABI_NETBSD_ELF | |
f4b3909f EZ |
2870 | NetBSD using the ELF executable format. |
2871 | ||
2872 | @findex GDB_OSABI_OPENBSD_ELF | |
2873 | @item GDB_OSABI_OPENBSD_ELF | |
2874 | OpenBSD using the ELF executable format. | |
70f80edf JT |
2875 | |
2876 | @findex GDB_OSABI_WINCE | |
2877 | @item GDB_OSABI_WINCE | |
f4b3909f | 2878 | Windows CE. |
70f80edf | 2879 | |
1029b7fa MK |
2880 | @findex GDB_OSABI_GO32 |
2881 | @item GDB_OSABI_GO32 | |
f4b3909f | 2882 | DJGPP. |
1029b7fa | 2883 | |
f4b3909f EZ |
2884 | @findex GDB_OSABI_IRIX |
2885 | @item GDB_OSABI_IRIX | |
2886 | Irix. | |
2887 | ||
f4b3909f EZ |
2888 | @findex GDB_OSABI_INTERIX |
2889 | @item GDB_OSABI_INTERIX | |
2890 | Interix (Posix layer for MS-Windows systems). | |
1029b7fa | 2891 | |
f4b3909f EZ |
2892 | @findex GDB_OSABI_HPUX_ELF |
2893 | @item GDB_OSABI_HPUX_ELF | |
2894 | HP/UX using the ELF executable format. | |
70f80edf | 2895 | |
f4b3909f EZ |
2896 | @findex GDB_OSABI_HPUX_SOM |
2897 | @item GDB_OSABI_HPUX_SOM | |
2898 | HP/UX using the SOM executable format. | |
70f80edf | 2899 | |
f4b3909f EZ |
2900 | @findex GDB_OSABI_QNXNTO |
2901 | @item GDB_OSABI_QNXNTO | |
2902 | QNX Neutrino. | |
2903 | ||
2904 | @findex GDB_OSABI_CYGWIN | |
2905 | @item GDB_OSABI_CYGWIN | |
2906 | Cygwin. | |
2907 | ||
2908 | @findex GDB_OSABI_AIX | |
2909 | @item GDB_OSABI_AIX | |
2910 | AIX. | |
70f80edf JT |
2911 | |
2912 | @end table | |
2913 | ||
2914 | Here are the functions that make up the OS ABI framework: | |
2915 | ||
2916 | @deftypefun const char *gdbarch_osabi_name (enum gdb_osabi @var{osabi}) | |
2917 | Return the name of the OS ABI corresponding to @var{osabi}. | |
2918 | @end deftypefun | |
2919 | ||
c133ab7a | 2920 | @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 | 2921 | Register the OS ABI handler specified by @var{init_osabi} for the |
c133ab7a MK |
2922 | architecture, machine type and OS ABI specified by @var{arch}, |
2923 | @var{machine} and @var{osabi}. In most cases, a value of zero for the | |
2924 | machine type, which implies the architecture's default machine type, | |
2925 | will suffice. | |
70f80edf JT |
2926 | @end deftypefun |
2927 | ||
2928 | @deftypefun void gdbarch_register_osabi_sniffer (enum bfd_architecture @var{arch}, enum bfd_flavour @var{flavour}, enum gdb_osabi (*@var{sniffer})(bfd *@var{abfd})) | |
2929 | Register the OS ABI file sniffer specified by @var{sniffer} for the | |
2930 | BFD architecture/flavour pair specified by @var{arch} and @var{flavour}. | |
2931 | If @var{arch} is @code{bfd_arch_unknown}, the sniffer is considered to | |
2932 | be generic, and is allowed to examine @var{flavour}-flavoured files for | |
2933 | any architecture. | |
2934 | @end deftypefun | |
2935 | ||
2936 | @deftypefun enum gdb_osabi gdbarch_lookup_osabi (bfd *@var{abfd}) | |
2937 | Examine the file described by @var{abfd} to determine its OS ABI. | |
2938 | The value @code{GDB_OSABI_UNKNOWN} is returned if the OS ABI cannot | |
2939 | be determined. | |
2940 | @end deftypefun | |
2941 | ||
2942 | @deftypefun void gdbarch_init_osabi (struct gdbarch info @var{info}, struct gdbarch *@var{gdbarch}, enum gdb_osabi @var{osabi}) | |
2943 | Invoke the OS ABI handler corresponding to @var{osabi} to fine-tune the | |
2944 | @code{gdbarch} structure specified by @var{gdbarch}. If a handler | |
2945 | corresponding to @var{osabi} has not been registered for @var{gdbarch}'s | |
2946 | architecture, a warning will be issued and the debugging session will continue | |
2947 | with the defaults already established for @var{gdbarch}. | |
2948 | @end deftypefun | |
2949 | ||
f4b3909f EZ |
2950 | @deftypefun void generic_elf_osabi_sniff_abi_tag_sections (bfd *@var{abfd}, asection *@var{sect}, void *@var{obj}) |
2951 | Helper routine for ELF file sniffers. Examine the file described by | |
2952 | @var{abfd} and look at ABI tag note sections to determine the OS ABI | |
2953 | from the note. This function should be called via | |
2954 | @code{bfd_map_over_sections}. | |
2955 | @end deftypefun | |
2956 | ||
b6fd0dfb | 2957 | @node Initialize New Architecture |
7a107747 DJ |
2958 | @section Initializing a New Architecture |
2959 | ||
2960 | Each @code{gdbarch} is associated with a single @sc{bfd} architecture, | |
2961 | via a @code{bfd_arch_@var{arch}} constant. The @code{gdbarch} is | |
2962 | registered by a call to @code{register_gdbarch_init}, usually from | |
2963 | the file's @code{_initialize_@var{filename}} routine, which will | |
2964 | be automatically called during @value{GDBN} startup. The arguments | |
2965 | are a @sc{bfd} architecture constant and an initialization function. | |
2966 | ||
2967 | The initialization function has this type: | |
2968 | ||
2969 | @smallexample | |
2970 | static struct gdbarch * | |
2971 | @var{arch}_gdbarch_init (struct gdbarch_info @var{info}, | |
2972 | struct gdbarch_list *@var{arches}) | |
2973 | @end smallexample | |
2974 | ||
2975 | The @var{info} argument contains parameters used to select the correct | |
2976 | architecture, and @var{arches} is a list of architectures which | |
2977 | have already been created with the same @code{bfd_arch_@var{arch}} | |
2978 | value. | |
2979 | ||
2980 | The initialization function should first make sure that @var{info} | |
2981 | is acceptable, and return @code{NULL} if it is not. Then, it should | |
2982 | search through @var{arches} for an exact match to @var{info}, and | |
2983 | return one if found. Lastly, if no exact match was found, it should | |
2984 | create a new architecture based on @var{info} and return it. | |
2985 | ||
2986 | Only information in @var{info} should be used to choose the new | |
2987 | architecture. Historically, @var{info} could be sparse, and | |
2988 | defaults would be collected from the first element on @var{arches}. | |
2989 | However, @value{GDBN} now fills in @var{info} more thoroughly, | |
2990 | so new @code{gdbarch} initialization functions should not take | |
2991 | defaults from @var{arches}. | |
2992 | ||
b6fd0dfb | 2993 | @node Registers and Memory |
c906108c SS |
2994 | @section Registers and Memory |
2995 | ||
56caf160 EZ |
2996 | @value{GDBN}'s model of the target machine is rather simple. |
2997 | @value{GDBN} assumes the machine includes a bank of registers and a | |
2998 | block of memory. Each register may have a different size. | |
c906108c | 2999 | |
56caf160 EZ |
3000 | @value{GDBN} does not have a magical way to match up with the |
3001 | compiler's idea of which registers are which; however, it is critical | |
3002 | that they do match up accurately. The only way to make this work is | |
3003 | to get accurate information about the order that the compiler uses, | |
4a9bb1df | 3004 | and to reflect that in the @code{gdbarch_register_name} and related functions. |
c906108c | 3005 | |
25822942 | 3006 | @value{GDBN} can handle big-endian, little-endian, and bi-endian architectures. |
c906108c | 3007 | |
b6fd0dfb | 3008 | @node Pointers and Addresses |
93e79dbd JB |
3009 | @section Pointers Are Not Always Addresses |
3010 | @cindex pointer representation | |
3011 | @cindex address representation | |
3012 | @cindex word-addressed machines | |
3013 | @cindex separate data and code address spaces | |
3014 | @cindex spaces, separate data and code address | |
3015 | @cindex address spaces, separate data and code | |
3016 | @cindex code pointers, word-addressed | |
3017 | @cindex converting between pointers and addresses | |
3018 | @cindex D10V addresses | |
3019 | ||
3020 | On almost all 32-bit architectures, the representation of a pointer is | |
3021 | indistinguishable from the representation of some fixed-length number | |
3022 | whose value is the byte address of the object pointed to. On such | |
56caf160 | 3023 | machines, the words ``pointer'' and ``address'' can be used interchangeably. |
93e79dbd JB |
3024 | However, architectures with smaller word sizes are often cramped for |
3025 | address space, so they may choose a pointer representation that breaks this | |
3026 | identity, and allows a larger code address space. | |
3027 | ||
1f70da6a SS |
3028 | @c D10V is gone from sources - more current example? |
3029 | ||
172c2a43 | 3030 | For example, the Renesas D10V is a 16-bit VLIW processor whose |
93e79dbd JB |
3031 | instructions are 32 bits long@footnote{Some D10V instructions are |
3032 | actually pairs of 16-bit sub-instructions. However, since you can't | |
3033 | jump into the middle of such a pair, code addresses can only refer to | |
3034 | full 32 bit instructions, which is what matters in this explanation.}. | |
3035 | If the D10V used ordinary byte addresses to refer to code locations, | |
3036 | then the processor would only be able to address 64kb of instructions. | |
3037 | However, since instructions must be aligned on four-byte boundaries, the | |
56caf160 EZ |
3038 | low two bits of any valid instruction's byte address are always |
3039 | zero---byte addresses waste two bits. So instead of byte addresses, | |
3040 | the D10V uses word addresses---byte addresses shifted right two bits---to | |
93e79dbd JB |
3041 | refer to code. Thus, the D10V can use 16-bit words to address 256kb of |
3042 | code space. | |
3043 | ||
3044 | However, this means that code pointers and data pointers have different | |
3045 | forms on the D10V. The 16-bit word @code{0xC020} refers to byte address | |
3046 | @code{0xC020} when used as a data address, but refers to byte address | |
3047 | @code{0x30080} when used as a code address. | |
3048 | ||
3049 | (The D10V also uses separate code and data address spaces, which also | |
3050 | affects the correspondence between pointers and addresses, but we're | |
3051 | going to ignore that here; this example is already too long.) | |
3052 | ||
56caf160 EZ |
3053 | To cope with architectures like this---the D10V is not the only |
3054 | one!---@value{GDBN} tries to distinguish between @dfn{addresses}, which are | |
93e79dbd JB |
3055 | byte numbers, and @dfn{pointers}, which are the target's representation |
3056 | of an address of a particular type of data. In the example above, | |
3057 | @code{0xC020} is the pointer, which refers to one of the addresses | |
3058 | @code{0xC020} or @code{0x30080}, depending on the type imposed upon it. | |
3059 | @value{GDBN} provides functions for turning a pointer into an address | |
3060 | and vice versa, in the appropriate way for the current architecture. | |
3061 | ||
3062 | Unfortunately, since addresses and pointers are identical on almost all | |
3063 | processors, this distinction tends to bit-rot pretty quickly. Thus, | |
3064 | each time you port @value{GDBN} to an architecture which does | |
3065 | distinguish between pointers and addresses, you'll probably need to | |
3066 | clean up some architecture-independent code. | |
3067 | ||
3068 | Here are functions which convert between pointers and addresses: | |
3069 | ||
3070 | @deftypefun CORE_ADDR extract_typed_address (void *@var{buf}, struct type *@var{type}) | |
3071 | Treat the bytes at @var{buf} as a pointer or reference of type | |
3072 | @var{type}, and return the address it represents, in a manner | |
3073 | appropriate for the current architecture. This yields an address | |
3074 | @value{GDBN} can use to read target memory, disassemble, etc. Note that | |
3075 | @var{buf} refers to a buffer in @value{GDBN}'s memory, not the | |
3076 | inferior's. | |
3077 | ||
3078 | For example, if the current architecture is the Intel x86, this function | |
3079 | extracts a little-endian integer of the appropriate length from | |
3080 | @var{buf} and returns it. However, if the current architecture is the | |
3081 | D10V, this function will return a 16-bit integer extracted from | |
3082 | @var{buf}, multiplied by four if @var{type} is a pointer to a function. | |
3083 | ||
3084 | If @var{type} is not a pointer or reference type, then this function | |
3085 | will signal an internal error. | |
3086 | @end deftypefun | |
3087 | ||
3088 | @deftypefun CORE_ADDR store_typed_address (void *@var{buf}, struct type *@var{type}, CORE_ADDR @var{addr}) | |
3089 | Store the address @var{addr} in @var{buf}, in the proper format for a | |
3090 | pointer of type @var{type} in the current architecture. Note that | |
3091 | @var{buf} refers to a buffer in @value{GDBN}'s memory, not the | |
3092 | inferior's. | |
3093 | ||
3094 | For example, if the current architecture is the Intel x86, this function | |
3095 | stores @var{addr} unmodified as a little-endian integer of the | |
3096 | appropriate length in @var{buf}. However, if the current architecture | |
3097 | is the D10V, this function divides @var{addr} by four if @var{type} is | |
3098 | a pointer to a function, and then stores it in @var{buf}. | |
3099 | ||
3100 | If @var{type} is not a pointer or reference type, then this function | |
3101 | will signal an internal error. | |
3102 | @end deftypefun | |
3103 | ||
f23631e4 | 3104 | @deftypefun CORE_ADDR value_as_address (struct value *@var{val}) |
93e79dbd JB |
3105 | Assuming that @var{val} is a pointer, return the address it represents, |
3106 | as appropriate for the current architecture. | |
3107 | ||
3108 | This function actually works on integral values, as well as pointers. | |
3109 | For pointers, it performs architecture-specific conversions as | |
3110 | described above for @code{extract_typed_address}. | |
3111 | @end deftypefun | |
3112 | ||
3113 | @deftypefun CORE_ADDR value_from_pointer (struct type *@var{type}, CORE_ADDR @var{addr}) | |
3114 | Create and return a value representing a pointer of type @var{type} to | |
3115 | the address @var{addr}, as appropriate for the current architecture. | |
3116 | This function performs architecture-specific conversions as described | |
3117 | above for @code{store_typed_address}. | |
3118 | @end deftypefun | |
3119 | ||
4a9bb1df | 3120 | Here are two functions which architectures can define to indicate the |
93e79dbd JB |
3121 | relationship between pointers and addresses. These have default |
3122 | definitions, appropriate for architectures on which all pointers are | |
fc0c74b1 | 3123 | simple unsigned byte addresses. |
93e79dbd | 3124 | |
4a9bb1df | 3125 | @deftypefun CORE_ADDR gdbarch_pointer_to_address (struct gdbarch *@var{current_gdbarch}, struct type *@var{type}, char *@var{buf}) |
93e79dbd JB |
3126 | Assume that @var{buf} holds a pointer of type @var{type}, in the |
3127 | appropriate format for the current architecture. Return the byte | |
3128 | address the pointer refers to. | |
3129 | ||
3130 | This function may safely assume that @var{type} is either a pointer or a | |
56caf160 | 3131 | C@t{++} reference type. |
4a9bb1df | 3132 | @end deftypefun |
93e79dbd | 3133 | |
4a9bb1df | 3134 | @deftypefun void gdbarch_address_to_pointer (struct gdbarch *@var{current_gdbarch}, struct type *@var{type}, char *@var{buf}, CORE_ADDR @var{addr}) |
93e79dbd JB |
3135 | Store in @var{buf} a pointer of type @var{type} representing the address |
3136 | @var{addr}, in the appropriate format for the current architecture. | |
3137 | ||
3138 | This function may safely assume that @var{type} is either a pointer or a | |
56caf160 | 3139 | C@t{++} reference type. |
4a9bb1df | 3140 | @end deftypefun |
93e79dbd | 3141 | |
b6fd0dfb | 3142 | @node Address Classes |
b5b0480a KB |
3143 | @section Address Classes |
3144 | @cindex address classes | |
3145 | @cindex DW_AT_byte_size | |
3146 | @cindex DW_AT_address_class | |
3147 | ||
3148 | Sometimes information about different kinds of addresses is available | |
3149 | via the debug information. For example, some programming environments | |
3150 | define addresses of several different sizes. If the debug information | |
3151 | distinguishes these kinds of address classes through either the size | |
3152 | info (e.g, @code{DW_AT_byte_size} in @w{DWARF 2}) or through an explicit | |
3153 | address class attribute (e.g, @code{DW_AT_address_class} in @w{DWARF 2}), the | |
3154 | following macros should be defined in order to disambiguate these | |
3155 | types within @value{GDBN} as well as provide the added information to | |
3156 | a @value{GDBN} user when printing type expressions. | |
3157 | ||
4a9bb1df | 3158 | @deftypefun int gdbarch_address_class_type_flags (struct gdbarch *@var{current_gdbarch}, int @var{byte_size}, int @var{dwarf2_addr_class}) |
b5b0480a KB |
3159 | Returns the type flags needed to construct a pointer type whose size |
3160 | is @var{byte_size} and whose address class is @var{dwarf2_addr_class}. | |
3161 | This function is normally called from within a symbol reader. See | |
3162 | @file{dwarf2read.c}. | |
4a9bb1df | 3163 | @end deftypefun |
b5b0480a | 3164 | |
4a9bb1df | 3165 | @deftypefun char *gdbarch_address_class_type_flags_to_name (struct gdbarch *@var{current_gdbarch}, int @var{type_flags}) |
b5b0480a KB |
3166 | Given the type flags representing an address class qualifier, return |
3167 | its name. | |
4a9bb1df | 3168 | @end deftypefun |
1f70da6a | 3169 | @deftypefun int gdbarch_address_class_name_to_type_flags (struct gdbarch *@var{current_gdbarch}, int @var{name}, int *@var{type_flags_ptr}) |
d3e8051b | 3170 | Given an address qualifier name, set the @code{int} referenced by @var{type_flags_ptr} to the type flags |
b5b0480a | 3171 | for that address class qualifier. |
4a9bb1df | 3172 | @end deftypefun |
b5b0480a KB |
3173 | |
3174 | Since the need for address classes is rather rare, none of | |
4a9bb1df UW |
3175 | the address class functions are defined by default. Predicate |
3176 | functions are provided to detect when they are defined. | |
b5b0480a KB |
3177 | |
3178 | Consider a hypothetical architecture in which addresses are normally | |
3179 | 32-bits wide, but 16-bit addresses are also supported. Furthermore, | |
3180 | suppose that the @w{DWARF 2} information for this architecture simply | |
3181 | uses a @code{DW_AT_byte_size} value of 2 to indicate the use of one | |
3182 | of these "short" pointers. The following functions could be defined | |
4a9bb1df | 3183 | to implement the address class functions: |
b5b0480a KB |
3184 | |
3185 | @smallexample | |
3186 | somearch_address_class_type_flags (int byte_size, | |
3187 | int dwarf2_addr_class) | |
f2abfe65 | 3188 | @{ |
b5b0480a KB |
3189 | if (byte_size == 2) |
3190 | return TYPE_FLAG_ADDRESS_CLASS_1; | |
3191 | else | |
3192 | return 0; | |
f2abfe65 | 3193 | @} |
b5b0480a KB |
3194 | |
3195 | static char * | |
3196 | somearch_address_class_type_flags_to_name (int type_flags) | |
f2abfe65 | 3197 | @{ |
b5b0480a KB |
3198 | if (type_flags & TYPE_FLAG_ADDRESS_CLASS_1) |
3199 | return "short"; | |
3200 | else | |
3201 | return NULL; | |
f2abfe65 | 3202 | @} |
b5b0480a KB |
3203 | |
3204 | int | |
3205 | somearch_address_class_name_to_type_flags (char *name, | |
3206 | int *type_flags_ptr) | |
f2abfe65 | 3207 | @{ |
b5b0480a | 3208 | if (strcmp (name, "short") == 0) |
f2abfe65 | 3209 | @{ |
b5b0480a KB |
3210 | *type_flags_ptr = TYPE_FLAG_ADDRESS_CLASS_1; |
3211 | return 1; | |
f2abfe65 | 3212 | @} |
b5b0480a KB |
3213 | else |
3214 | return 0; | |
f2abfe65 | 3215 | @} |
b5b0480a KB |
3216 | @end smallexample |
3217 | ||
3218 | The qualifier @code{@@short} is used in @value{GDBN}'s type expressions | |
3219 | to indicate the presence of one of these "short" pointers. E.g, if | |
3220 | the debug information indicates that @code{short_ptr_var} is one of these | |
3221 | short pointers, @value{GDBN} might show the following behavior: | |
3222 | ||
3223 | @smallexample | |
3224 | (gdb) ptype short_ptr_var | |
3225 | type = int * @@short | |
3226 | @end smallexample | |
3227 | ||
93e79dbd | 3228 | |
b6fd0dfb | 3229 | @node Raw and Virtual Registers |
13d01224 AC |
3230 | @section Raw and Virtual Register Representations |
3231 | @cindex raw register representation | |
3232 | @cindex virtual register representation | |
3233 | @cindex representations, raw and virtual registers | |
3234 | ||
3235 | @emph{Maintainer note: This section is pretty much obsolete. The | |
3236 | functionality described here has largely been replaced by | |
d0384fc4 TJB |
3237 | pseudo-registers and the mechanisms described in @ref{Register and |
3238 | Memory Data, , Using Different Register and Memory Data | |
13d01224 AC |
3239 | Representations}. See also @uref{http://www.gnu.org/software/gdb/bugs/, |
3240 | Bug Tracking Database} and | |
3241 | @uref{http://sources.redhat.com/gdb/current/ari/, ARI Index} for more | |
3242 | up-to-date information.} | |
af6c57ea | 3243 | |
9fb4dd36 JB |
3244 | Some architectures use one representation for a value when it lives in a |
3245 | register, but use a different representation when it lives in memory. | |
25822942 | 3246 | In @value{GDBN}'s terminology, the @dfn{raw} representation is the one used in |
9fb4dd36 | 3247 | the target registers, and the @dfn{virtual} representation is the one |
25822942 | 3248 | used in memory, and within @value{GDBN} @code{struct value} objects. |
9fb4dd36 | 3249 | |
13d01224 AC |
3250 | @emph{Maintainer note: Notice that the same mechanism is being used to |
3251 | both convert a register to a @code{struct value} and alternative | |
3252 | register forms.} | |
3253 | ||
9fb4dd36 JB |
3254 | For almost all data types on almost all architectures, the virtual and |
3255 | raw representations are identical, and no special handling is needed. | |
3256 | However, they do occasionally differ. For example: | |
3257 | ||
3258 | @itemize @bullet | |
9fb4dd36 | 3259 | @item |
56caf160 | 3260 | The x86 architecture supports an 80-bit @code{long double} type. However, when |
9fb4dd36 JB |
3261 | we store those values in memory, they occupy twelve bytes: the |
3262 | floating-point number occupies the first ten, and the final two bytes | |
3263 | are unused. This keeps the values aligned on four-byte boundaries, | |
3264 | allowing more efficient access. Thus, the x86 80-bit floating-point | |
3265 | type is the raw representation, and the twelve-byte loosely-packed | |
3266 | arrangement is the virtual representation. | |
3267 | ||
3268 | @item | |
25822942 DB |
3269 | Some 64-bit MIPS targets present 32-bit registers to @value{GDBN} as 64-bit |
3270 | registers, with garbage in their upper bits. @value{GDBN} ignores the top 32 | |
9fb4dd36 JB |
3271 | bits. Thus, the 64-bit form, with garbage in the upper 32 bits, is the |
3272 | raw representation, and the trimmed 32-bit representation is the | |
3273 | virtual representation. | |
9fb4dd36 JB |
3274 | @end itemize |
3275 | ||
3276 | In general, the raw representation is determined by the architecture, or | |
25822942 DB |
3277 | @value{GDBN}'s interface to the architecture, while the virtual representation |
3278 | can be chosen for @value{GDBN}'s convenience. @value{GDBN}'s register file, | |
56caf160 EZ |
3279 | @code{registers}, holds the register contents in raw format, and the |
3280 | @value{GDBN} remote protocol transmits register values in raw format. | |
9fb4dd36 | 3281 | |
56caf160 EZ |
3282 | Your architecture may define the following macros to request |
3283 | conversions between the raw and virtual format: | |
9fb4dd36 JB |
3284 | |
3285 | @deftypefn {Target Macro} int REGISTER_CONVERTIBLE (int @var{reg}) | |
3286 | Return non-zero if register number @var{reg}'s value needs different raw | |
3287 | and virtual formats. | |
6f6ef15a EZ |
3288 | |
3289 | You should not use @code{REGISTER_CONVERT_TO_VIRTUAL} for a register | |
3290 | unless this macro returns a non-zero value for that register. | |
9fb4dd36 JB |
3291 | @end deftypefn |
3292 | ||
9fb4dd36 JB |
3293 | @deftypefn {Target Macro} void REGISTER_CONVERT_TO_VIRTUAL (int @var{reg}, struct type *@var{type}, char *@var{from}, char *@var{to}) |
3294 | Convert the value of register number @var{reg} to @var{type}, which | |
1f70da6a | 3295 | should always be @code{gdbarch_register_type (@var{reg})}. The buffer |
9fb4dd36 JB |
3296 | at @var{from} holds the register's value in raw format; the macro should |
3297 | convert the value to virtual format, and place it at @var{to}. | |
3298 | ||
6f6ef15a EZ |
3299 | Note that @code{REGISTER_CONVERT_TO_VIRTUAL} and |
3300 | @code{REGISTER_CONVERT_TO_RAW} take their @var{reg} and @var{type} | |
3301 | arguments in different orders. | |
3302 | ||
3303 | You should only use @code{REGISTER_CONVERT_TO_VIRTUAL} with registers | |
3304 | for which the @code{REGISTER_CONVERTIBLE} macro returns a non-zero | |
3305 | value. | |
9fb4dd36 JB |
3306 | @end deftypefn |
3307 | ||
3308 | @deftypefn {Target Macro} void REGISTER_CONVERT_TO_RAW (struct type *@var{type}, int @var{reg}, char *@var{from}, char *@var{to}) | |
3309 | Convert the value of register number @var{reg} to @var{type}, which | |
1f70da6a | 3310 | should always be @code{gdbarch_register_type (@var{reg})}. The buffer |
9fb4dd36 JB |
3311 | at @var{from} holds the register's value in raw format; the macro should |
3312 | convert the value to virtual format, and place it at @var{to}. | |
3313 | ||
3314 | Note that REGISTER_CONVERT_TO_VIRTUAL and REGISTER_CONVERT_TO_RAW take | |
3315 | their @var{reg} and @var{type} arguments in different orders. | |
3316 | @end deftypefn | |
3317 | ||
3318 | ||
b6fd0dfb | 3319 | @node Register and Memory Data |
13d01224 AC |
3320 | @section Using Different Register and Memory Data Representations |
3321 | @cindex register representation | |
3322 | @cindex memory representation | |
3323 | @cindex representations, register and memory | |
3324 | @cindex register data formats, converting | |
3325 | @cindex @code{struct value}, converting register contents to | |
3326 | ||
3327 | @emph{Maintainer's note: The way GDB manipulates registers is undergoing | |
d3e8051b | 3328 | significant change. Many of the macros and functions referred to in this |
13d01224 AC |
3329 | section are likely to be subject to further revision. See |
3330 | @uref{http://sources.redhat.com/gdb/current/ari/, A.R. Index} and | |
3331 | @uref{http://www.gnu.org/software/gdb/bugs, Bug Tracking Database} for | |
3332 | further information. cagney/2002-05-06.} | |
3333 | ||
3334 | Some architectures can represent a data object in a register using a | |
3335 | form that is different to the objects more normal memory representation. | |
3336 | For example: | |
3337 | ||
3338 | @itemize @bullet | |
3339 | ||
3340 | @item | |
3341 | The Alpha architecture can represent 32 bit integer values in | |
3342 | floating-point registers. | |
3343 | ||
3344 | @item | |
3345 | The x86 architecture supports 80-bit floating-point registers. The | |
3346 | @code{long double} data type occupies 96 bits in memory but only 80 bits | |
3347 | when stored in a register. | |
3348 | ||
3349 | @end itemize | |
3350 | ||
3351 | In general, the register representation of a data type is determined by | |
3352 | the architecture, or @value{GDBN}'s interface to the architecture, while | |
3353 | the memory representation is determined by the Application Binary | |
3354 | Interface. | |
3355 | ||
3356 | For almost all data types on almost all architectures, the two | |
3357 | representations are identical, and no special handling is needed. | |
3358 | However, they do occasionally differ. Your architecture may define the | |
3359 | following macros to request conversions between the register and memory | |
3360 | representations of a data type: | |
3361 | ||
4a9bb1df | 3362 | @deftypefun int gdbarch_convert_register_p (struct gdbarch *@var{gdbarch}, int @var{reg}) |
13d01224 AC |
3363 | Return non-zero if the representation of a data value stored in this |
3364 | register may be different to the representation of that same data value | |
3365 | when stored in memory. | |
3366 | ||
4a9bb1df UW |
3367 | When non-zero, the macros @code{gdbarch_register_to_value} and |
3368 | @code{value_to_register} are used to perform any necessary conversion. | |
83acabca DJ |
3369 | |
3370 | This function should return zero for the register's native type, when | |
3371 | no conversion is necessary. | |
4a9bb1df | 3372 | @end deftypefun |
13d01224 | 3373 | |
4a9bb1df | 3374 | @deftypefun void gdbarch_register_to_value (struct gdbarch *@var{gdbarch}, int @var{reg}, struct type *@var{type}, char *@var{from}, char *@var{to}) |
13d01224 AC |
3375 | Convert the value of register number @var{reg} to a data object of type |
3376 | @var{type}. The buffer at @var{from} holds the register's value in raw | |
3377 | format; the converted value should be placed in the buffer at @var{to}. | |
3378 | ||
4a9bb1df UW |
3379 | Note that @code{gdbarch_register_to_value} and @code{gdbarch_value_to_register} |
3380 | take their @var{reg} and @var{type} arguments in different orders. | |
13d01224 | 3381 | |
4a9bb1df UW |
3382 | You should only use @code{gdbarch_register_to_value} with registers for which |
3383 | the @code{gdbarch_convert_register_p} function returns a non-zero value. | |
3384 | @end deftypefun | |
13d01224 | 3385 | |
4a9bb1df | 3386 | @deftypefun void gdbarch_value_to_register (struct gdbarch *@var{gdbarch}, struct type *@var{type}, int @var{reg}, char *@var{from}, char *@var{to}) |
13d01224 AC |
3387 | Convert a data value of type @var{type} to register number @var{reg}' |
3388 | raw format. | |
3389 | ||
4a9bb1df UW |
3390 | Note that @code{gdbarch_register_to_value} and @code{gdbarch_value_to_register} |
3391 | take their @var{reg} and @var{type} arguments in different orders. | |
13d01224 | 3392 | |
4a9bb1df UW |
3393 | You should only use @code{gdbarch_value_to_register} with registers for which |
3394 | the @code{gdbarch_convert_register_p} function returns a non-zero value. | |
3395 | @end deftypefun | |
13d01224 | 3396 | |
b6fd0dfb | 3397 | @node Frame Interpretation |
c906108c SS |
3398 | @section Frame Interpretation |
3399 | ||
b6fd0dfb | 3400 | @node Inferior Call Setup |
c906108c SS |
3401 | @section Inferior Call Setup |
3402 | ||
b6fd0dfb | 3403 | @node Compiler Characteristics |
c906108c SS |
3404 | @section Compiler Characteristics |
3405 | ||
b6fd0dfb | 3406 | @node Target Conditionals |
c906108c SS |
3407 | @section Target Conditionals |
3408 | ||
4a9bb1df UW |
3409 | This section describes the macros and functions that you can use to define the |
3410 | target machine. | |
c906108c SS |
3411 | |
3412 | @table @code | |
3413 | ||
4a9bb1df UW |
3414 | @item CORE_ADDR gdbarch_addr_bits_remove (@var{gdbarch}, @var{addr}) |
3415 | @findex gdbarch_addr_bits_remove | |
adf40b2e | 3416 | If a raw machine instruction address includes any bits that are not |
4a9bb1df UW |
3417 | really part of the address, then this function is used to zero those bits in |
3418 | @var{addr}. This is only used for addresses of instructions, and even then not | |
3419 | in all contexts. | |
adf40b2e JM |
3420 | |
3421 | For example, the two low-order bits of the PC on the Hewlett-Packard PA | |
3422 | 2.0 architecture contain the privilege level of the corresponding | |
3423 | instruction. Since instructions must always be aligned on four-byte | |
3424 | boundaries, the processor masks out these bits to generate the actual | |
4a9bb1df UW |
3425 | address of the instruction. @code{gdbarch_addr_bits_remove} would then for |
3426 | example look like that: | |
3427 | @smallexample | |
3428 | arch_addr_bits_remove (CORE_ADDR addr) | |
3429 | @{ | |
3430 | return (addr &= ~0x3); | |
3431 | @} | |
3432 | @end smallexample | |
c906108c | 3433 | |
4a9bb1df UW |
3434 | @item int address_class_name_to_type_flags (@var{gdbarch}, @var{name}, @var{type_flags_ptr}) |
3435 | @findex address_class_name_to_type_flags | |
b5b0480a KB |
3436 | If @var{name} is a valid address class qualifier name, set the @code{int} |
3437 | referenced by @var{type_flags_ptr} to the mask representing the qualifier | |
3438 | and return 1. If @var{name} is not a valid address class qualifier name, | |
3439 | return 0. | |
3440 | ||
3441 | The value for @var{type_flags_ptr} should be one of | |
3442 | @code{TYPE_FLAG_ADDRESS_CLASS_1}, @code{TYPE_FLAG_ADDRESS_CLASS_2}, or | |
3443 | possibly some combination of these values or'd together. | |
3444 | @xref{Target Architecture Definition, , Address Classes}. | |
3445 | ||
4a9bb1df UW |
3446 | @item int address_class_name_to_type_flags_p (@var{gdbarch}) |
3447 | @findex address_class_name_to_type_flags_p | |
3448 | Predicate which indicates whether @code{address_class_name_to_type_flags} | |
b5b0480a KB |
3449 | has been defined. |
3450 | ||
4a9bb1df UW |
3451 | @item int gdbarch_address_class_type_flags (@var{gdbarch}, @var{byte_size}, @var{dwarf2_addr_class}) |
3452 | @findex gdbarch_address_class_type_flags | |
b5b0480a KB |
3453 | Given a pointers byte size (as described by the debug information) and |
3454 | the possible @code{DW_AT_address_class} value, return the type flags | |
3455 | used by @value{GDBN} to represent this address class. The value | |
3456 | returned should be one of @code{TYPE_FLAG_ADDRESS_CLASS_1}, | |
3457 | @code{TYPE_FLAG_ADDRESS_CLASS_2}, or possibly some combination of these | |
3458 | values or'd together. | |
3459 | @xref{Target Architecture Definition, , Address Classes}. | |
3460 | ||
4a9bb1df UW |
3461 | @item int gdbarch_address_class_type_flags_p (@var{gdbarch}) |
3462 | @findex gdbarch_address_class_type_flags_p | |
3463 | Predicate which indicates whether @code{gdbarch_address_class_type_flags_p} has | |
b5b0480a KB |
3464 | been defined. |
3465 | ||
4a9bb1df UW |
3466 | @item const char *gdbarch_address_class_type_flags_to_name (@var{gdbarch}, @var{type_flags}) |
3467 | @findex gdbarch_address_class_type_flags_to_name | |
b5b0480a KB |
3468 | Return the name of the address class qualifier associated with the type |
3469 | flags given by @var{type_flags}. | |
3470 | ||
4a9bb1df UW |
3471 | @item int gdbarch_address_class_type_flags_to_name_p (@var{gdbarch}) |
3472 | @findex gdbarch_address_class_type_flags_to_name_p | |
3473 | Predicate which indicates whether @code{gdbarch_address_class_type_flags_to_name} has been defined. | |
b5b0480a KB |
3474 | @xref{Target Architecture Definition, , Address Classes}. |
3475 | ||
4a9bb1df UW |
3476 | @item void gdbarch_address_to_pointer (@var{gdbarch}, @var{type}, @var{buf}, @var{addr}) |
3477 | @findex gdbarch_address_to_pointer | |
93e79dbd JB |
3478 | Store in @var{buf} a pointer of type @var{type} representing the address |
3479 | @var{addr}, in the appropriate format for the current architecture. | |
4a9bb1df | 3480 | This function may safely assume that @var{type} is either a pointer or a |
56caf160 | 3481 | C@t{++} reference type. |
93e79dbd JB |
3482 | @xref{Target Architecture Definition, , Pointers Are Not Always Addresses}. |
3483 | ||
4a9bb1df UW |
3484 | @item int gdbarch_believe_pcc_promotion (@var{gdbarch}) |
3485 | @findex gdbarch_believe_pcc_promotion | |
3486 | Used to notify if the compiler promotes a @code{short} or @code{char} | |
56caf160 EZ |
3487 | parameter to an @code{int}, but still reports the parameter as its |
3488 | original type, rather than the promoted type. | |
c906108c | 3489 | |
32c9a795 MD |
3490 | @item gdbarch_bits_big_endian (@var{gdbarch}) |
3491 | @findex gdbarch_bits_big_endian | |
3492 | This is used if the numbering of bits in the targets does @strong{not} match | |
3493 | the endianness of the target byte order. A value of 1 means that the bits | |
56caf160 | 3494 | are numbered in a big-endian bit order, 0 means little-endian. |
c906108c | 3495 | |
32c9a795 MD |
3496 | @item set_gdbarch_bits_big_endian (@var{gdbarch}, @var{bits_big_endian}) |
3497 | @findex set_gdbarch_bits_big_endian | |
3498 | Calling set_gdbarch_bits_big_endian with a value of 1 indicates that the | |
3499 | bits in the target are numbered in a big-endian bit order, 0 indicates | |
3500 | little-endian. | |
3501 | ||
c906108c | 3502 | @item BREAKPOINT |
56caf160 | 3503 | @findex BREAKPOINT |
c906108c SS |
3504 | This is the character array initializer for the bit pattern to put into |
3505 | memory where a breakpoint is set. Although it's common to use a trap | |
3506 | instruction for a breakpoint, it's not required; for instance, the bit | |
3507 | pattern could be an invalid instruction. The breakpoint must be no | |
3508 | longer than the shortest instruction of the architecture. | |
3509 | ||
56caf160 | 3510 | @code{BREAKPOINT} has been deprecated in favor of |
4a9bb1df | 3511 | @code{gdbarch_breakpoint_from_pc}. |
7a292a7a | 3512 | |
c906108c | 3513 | @item BIG_BREAKPOINT |
56caf160 EZ |
3514 | @itemx LITTLE_BREAKPOINT |
3515 | @findex LITTLE_BREAKPOINT | |
3516 | @findex BIG_BREAKPOINT | |
c906108c SS |
3517 | Similar to BREAKPOINT, but used for bi-endian targets. |
3518 | ||
56caf160 | 3519 | @code{BIG_BREAKPOINT} and @code{LITTLE_BREAKPOINT} have been deprecated in |
4a9bb1df | 3520 | favor of @code{gdbarch_breakpoint_from_pc}. |
7a292a7a | 3521 | |
4a9bb1df UW |
3522 | @item const gdb_byte *gdbarch_breakpoint_from_pc (@var{gdbarch}, @var{pcptr}, @var{lenptr}) |
3523 | @findex gdbarch_breakpoint_from_pc | |
3524 | @anchor{gdbarch_breakpoint_from_pc} Use the program counter to determine the | |
2dd0da42 | 3525 | contents and size of a breakpoint instruction. It returns a pointer to |
a655d424 | 3526 | a static string of bytes that encode a breakpoint instruction, stores the |
2dd0da42 AC |
3527 | length of the string to @code{*@var{lenptr}}, and adjusts the program |
3528 | counter (if necessary) to point to the actual memory location where the | |
a655d424 JK |
3529 | breakpoint should be inserted. May return @code{NULL} to indicate that |
3530 | software breakpoints are not supported. | |
c906108c SS |
3531 | |
3532 | Although it is common to use a trap instruction for a breakpoint, it's | |
3533 | not required; for instance, the bit pattern could be an invalid | |
3534 | instruction. The breakpoint must be no longer than the shortest | |
3535 | instruction of the architecture. | |
3536 | ||
a655d424 JK |
3537 | Provided breakpoint bytes can be also used by @code{bp_loc_is_permanent} to |
3538 | detect permanent breakpoints. @code{gdbarch_breakpoint_from_pc} should return | |
3539 | an unchanged memory copy if it was called for a location with permanent | |
3540 | breakpoint as some architectures use breakpoint instructions containing | |
3541 | arbitrary parameter value. | |
3542 | ||
7a292a7a SS |
3543 | Replaces all the other @var{BREAKPOINT} macros. |
3544 | ||
4a9bb1df UW |
3545 | @item int gdbarch_memory_insert_breakpoint (@var{gdbarch}, @var{bp_tgt}) |
3546 | @itemx gdbarch_memory_remove_breakpoint (@var{gdbarch}, @var{bp_tgt}) | |
3547 | @findex gdbarch_memory_remove_breakpoint | |
3548 | @findex gdbarch_memory_insert_breakpoint | |
917317f4 JM |
3549 | Insert or remove memory based breakpoints. Reasonable defaults |
3550 | (@code{default_memory_insert_breakpoint} and | |
3551 | @code{default_memory_remove_breakpoint} respectively) have been | |
4a9bb1df UW |
3552 | provided so that it is not necessary to set these for most |
3553 | architectures. Architectures which may want to set | |
3554 | @code{gdbarch_memory_insert_breakpoint} and @code{gdbarch_memory_remove_breakpoint} will likely have instructions that are oddly sized or are not stored in a | |
917317f4 JM |
3555 | conventional manner. |
3556 | ||
3557 | It may also be desirable (from an efficiency standpoint) to define | |
3558 | custom breakpoint insertion and removal routines if | |
4a9bb1df | 3559 | @code{gdbarch_breakpoint_from_pc} needs to read the target's memory for some |
917317f4 JM |
3560 | reason. |
3561 | ||
4a9bb1df UW |
3562 | @item CORE_ADDR gdbarch_adjust_breakpoint_address (@var{gdbarch}, @var{bpaddr}) |
3563 | @findex gdbarch_adjust_breakpoint_address | |
1485d690 KB |
3564 | @cindex breakpoint address adjusted |
3565 | Given an address at which a breakpoint is desired, return a breakpoint | |
3566 | address adjusted to account for architectural constraints on | |
3567 | breakpoint placement. This method is not needed by most targets. | |
3568 | ||
3569 | The FR-V target (see @file{frv-tdep.c}) requires this method. | |
3570 | The FR-V is a VLIW architecture in which a number of RISC-like | |
3571 | instructions are grouped (packed) together into an aggregate | |
3572 | instruction or instruction bundle. When the processor executes | |
3573 | one of these bundles, the component instructions are executed | |
3574 | in parallel. | |
3575 | ||
3576 | In the course of optimization, the compiler may group instructions | |
3577 | from distinct source statements into the same bundle. The line number | |
3578 | information associated with one of the latter statements will likely | |
3579 | refer to some instruction other than the first one in the bundle. So, | |
3580 | if the user attempts to place a breakpoint on one of these latter | |
3581 | statements, @value{GDBN} must be careful to @emph{not} place the break | |
3582 | instruction on any instruction other than the first one in the bundle. | |
3583 | (Remember though that the instructions within a bundle execute | |
3584 | in parallel, so the @emph{first} instruction is the instruction | |
3585 | at the lowest address and has nothing to do with execution order.) | |
3586 | ||
4a9bb1df | 3587 | The FR-V's @code{gdbarch_adjust_breakpoint_address} method will adjust a |
1485d690 KB |
3588 | breakpoint's address by scanning backwards for the beginning of |
3589 | the bundle, returning the address of the bundle. | |
3590 | ||
3591 | Since the adjustment of a breakpoint may significantly alter a user's | |
3592 | expectation, @value{GDBN} prints a warning when an adjusted breakpoint | |
3593 | is initially set and each time that that breakpoint is hit. | |
3594 | ||
4a9bb1df UW |
3595 | @item int gdbarch_call_dummy_location (@var{gdbarch}) |
3596 | @findex gdbarch_call_dummy_location | |
56caf160 | 3597 | See the file @file{inferior.h}. |
7a292a7a | 3598 | |
4a9bb1df UW |
3599 | This method has been replaced by @code{gdbarch_push_dummy_code} |
3600 | (@pxref{gdbarch_push_dummy_code}). | |
7043d8dc | 3601 | |
4a9bb1df UW |
3602 | @item int gdbarch_cannot_fetch_register (@var{gdbarch}, @var{regum}) |
3603 | @findex gdbarch_cannot_fetch_register | |
3604 | This function should return nonzero if @var{regno} cannot be fetched | |
a53f55d8 | 3605 | from an inferior process. |
c906108c | 3606 | |
4a9bb1df UW |
3607 | @item int gdbarch_cannot_store_register (@var{gdbarch}, @var{regnum}) |
3608 | @findex gdbarch_cannot_store_register | |
3609 | This function should return nonzero if @var{regno} should not be | |
c906108c | 3610 | written to the target. This is often the case for program counters, |
4a9bb1df UW |
3611 | status words, and other special registers. This function returns 0 as |
3612 | default so that @value{GDBN} will assume that all registers may be written. | |
c906108c | 3613 | |
4a9bb1df UW |
3614 | @item int gdbarch_convert_register_p (@var{gdbarch}, @var{regnum}, struct type *@var{type}) |
3615 | @findex gdbarch_convert_register_p | |
83acabca DJ |
3616 | Return non-zero if register @var{regnum} represents data values of type |
3617 | @var{type} in a non-standard form. | |
13d01224 AC |
3618 | @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. |
3619 | ||
a53f55d8 PA |
3620 | @item int gdbarch_fp0_regnum (@var{gdbarch}) |
3621 | @findex gdbarch_fp0_regnum | |
3622 | This function returns the number of the first floating point register, | |
3623 | if the machine has such registers. Otherwise, it returns -1. | |
3624 | ||
4a9bb1df UW |
3625 | @item CORE_ADDR gdbarch_decr_pc_after_break (@var{gdbarch}) |
3626 | @findex gdbarch_decr_pc_after_break | |
3627 | This function shall return the amount by which to decrement the PC after the | |
c906108c | 3628 | program encounters a breakpoint. This is often the number of bytes in |
56caf160 | 3629 | @code{BREAKPOINT}, though not always. For most targets this value will be 0. |
c906108c | 3630 | |
56caf160 EZ |
3631 | @item DISABLE_UNSETTABLE_BREAK (@var{addr}) |
3632 | @findex DISABLE_UNSETTABLE_BREAK | |
c906108c SS |
3633 | If defined, this should evaluate to 1 if @var{addr} is in a shared |
3634 | library in which breakpoints cannot be set and so should be disabled. | |
3635 | ||
5fc14d0a | 3636 | @item void gdbarch_print_float_info (@var{gdbarch}, @var{file}, @var{frame}, @var{args}) |
4a9bb1df | 3637 | @findex gdbarch_print_float_info |
5e74b15c RE |
3638 | If defined, then the @samp{info float} command will print information about |
3639 | the processor's floating point unit. | |
3640 | ||
4a9bb1df UW |
3641 | @item void gdbarch_print_registers_info (@var{gdbarch}, @var{frame}, @var{regnum}, @var{all}) |
3642 | @findex gdbarch_print_registers_info | |
0ab7a791 AC |
3643 | If defined, pretty print the value of the register @var{regnum} for the |
3644 | specified @var{frame}. If the value of @var{regnum} is -1, pretty print | |
3645 | either all registers (@var{all} is non zero) or a select subset of | |
3646 | registers (@var{all} is zero). | |
3647 | ||
3648 | The default method prints one register per line, and if @var{all} is | |
3649 | zero omits floating-point registers. | |
3650 | ||
4a9bb1df UW |
3651 | @item int gdbarch_print_vector_info (@var{gdbarch}, @var{file}, @var{frame}, @var{args}) |
3652 | @findex gdbarch_print_vector_info | |
e76f1f2e AC |
3653 | If defined, then the @samp{info vector} command will call this function |
3654 | to print information about the processor's vector unit. | |
3655 | ||
3656 | By default, the @samp{info vector} command will print all vector | |
3657 | registers (the register's type having the vector attribute). | |
3658 | ||
4a9bb1df UW |
3659 | @item int gdbarch_dwarf2_reg_to_regnum (@var{gdbarch}, @var{dwarf2_regnr}) |
3660 | @findex gdbarch_dwarf2_reg_to_regnum | |
3661 | Convert DWARF2 register number @var{dwarf2_regnr} into @value{GDBN} regnum. | |
3662 | If not defined, no conversion will be performed. | |
0dcedd82 | 3663 | |
4a9bb1df UW |
3664 | @item int gdbarch_ecoff_reg_to_regnum (@var{gdbarch}, @var{ecoff_regnr}) |
3665 | @findex gdbarch_ecoff_reg_to_regnum | |
3666 | Convert ECOFF register number @var{ecoff_regnr} into @value{GDBN} regnum. If | |
3667 | not defined, no conversion will be performed. | |
c906108c | 3668 | |
4a9bb1df | 3669 | @item CORE_ADDR frame_align (@var{gdbarch}, @var{address}) |
790eb8f5 AC |
3670 | @anchor{frame_align} |
3671 | @findex frame_align | |
3672 | Define this to adjust @var{address} so that it meets the alignment | |
3673 | requirements for the start of a new stack frame. A stack frame's | |
3674 | alignment requirements are typically stronger than a target processors | |
5fc14d0a | 3675 | stack alignment requirements. |
790eb8f5 AC |
3676 | |
3677 | This function is used to ensure that, when creating a dummy frame, both | |
3678 | the initial stack pointer and (if needed) the address of the return | |
3679 | value are correctly aligned. | |
3680 | ||
5fc14d0a EZ |
3681 | This function always adjusts the address in the direction of stack |
3682 | growth. | |
790eb8f5 AC |
3683 | |
3684 | By default, no frame based stack alignment is performed. | |
3685 | ||
4a9bb1df UW |
3686 | @item int gdbarch_frame_red_zone_size (@var{gdbarch}) |
3687 | @findex gdbarch_frame_red_zone_size | |
8b148df9 AC |
3688 | The number of bytes, beyond the innermost-stack-address, reserved by the |
3689 | @sc{abi}. A function is permitted to use this scratch area (instead of | |
3690 | allocating extra stack space). | |
3691 | ||
3692 | When performing an inferior function call, to ensure that it does not | |
3693 | modify this area, @value{GDBN} adjusts the innermost-stack-address by | |
4a9bb1df | 3694 | @var{gdbarch_frame_red_zone_size} bytes before pushing parameters onto the |
8b148df9 AC |
3695 | stack. |
3696 | ||
3697 | By default, zero bytes are allocated. The value must be aligned | |
3698 | (@pxref{frame_align}). | |
3699 | ||
3700 | The @sc{amd64} (nee x86-64) @sc{abi} documentation refers to the | |
3701 | @emph{red zone} when describing this scratch area. | |
3702 | @cindex red zone | |
3703 | ||
fb8f8949 | 3704 | @code{FRAME_FIND_SAVED_REGS} is deprecated. |
c906108c | 3705 | |
4a9bb1df UW |
3706 | @item int gdbarch_frame_num_args (@var{gdbarch}, @var{frame}) |
3707 | @findex gdbarch_frame_num_args | |
3708 | For the frame described by @var{frame} return the number of arguments that | |
392a587b JM |
3709 | are being passed. If the number of arguments is not known, return |
3710 | @code{-1}. | |
c906108c | 3711 | |
4a9bb1df UW |
3712 | @item CORE_ADDR gdbarch_unwind_pc (@var{next_frame}) |
3713 | @findex gdbarch_unwind_pc | |
3714 | @anchor{gdbarch_unwind_pc} Return the instruction address, in | |
3715 | @var{next_frame}'s caller, at which execution will resume after | |
3716 | @var{next_frame} returns. This is commonly referred to as the return address. | |
12cc2063 AC |
3717 | |
3718 | The implementation, which must be frame agnostic (work with any frame), | |
3719 | is typically no more than: | |
3720 | ||
3721 | @smallexample | |
3722 | ULONGEST pc; | |
11411de3 | 3723 | pc = frame_unwind_register_unsigned (next_frame, S390_PC_REGNUM); |
4a9bb1df | 3724 | return gdbarch_addr_bits_remove (gdbarch, pc); |
12cc2063 AC |
3725 | @end smallexample |
3726 | ||
3727 | @noindent | |
c906108c | 3728 | |
4a9bb1df UW |
3729 | @item CORE_ADDR gdbarch_unwind_sp (@var{gdbarch}, @var{next_frame}) |
3730 | @findex gdbarch_unwind_sp | |
3731 | @anchor{gdbarch_unwind_sp} Return the frame's inner most stack address. This is | |
d3e8051b | 3732 | commonly referred to as the frame's @dfn{stack pointer}. |
a9e5fdc2 AC |
3733 | |
3734 | The implementation, which must be frame agnostic (work with any frame), | |
3735 | is typically no more than: | |
3736 | ||
3737 | @smallexample | |
3738 | ULONGEST sp; | |
11411de3 | 3739 | sp = frame_unwind_register_unsigned (next_frame, S390_SP_REGNUM); |
4a9bb1df | 3740 | return gdbarch_addr_bits_remove (gdbarch, sp); |
a9e5fdc2 AC |
3741 | @end smallexample |
3742 | ||
3743 | @noindent | |
3744 | @xref{TARGET_READ_SP}, which this method replaces. | |
3745 | ||
c906108c | 3746 | @item GCC_COMPILED_FLAG_SYMBOL |
56caf160 EZ |
3747 | @itemx GCC2_COMPILED_FLAG_SYMBOL |
3748 | @findex GCC2_COMPILED_FLAG_SYMBOL | |
3749 | @findex GCC_COMPILED_FLAG_SYMBOL | |
3750 | If defined, these are the names of the symbols that @value{GDBN} will | |
3751 | look for to detect that GCC compiled the file. The default symbols | |
3752 | are @code{gcc_compiled.} and @code{gcc2_compiled.}, | |
3753 | respectively. (Currently only defined for the Delta 68.) | |
c906108c | 3754 | |
4a9bb1df UW |
3755 | @item gdbarch_get_longjmp_target |
3756 | @findex gdbarch_get_longjmp_target | |
1f70da6a SS |
3757 | This function determines the target PC address that @code{longjmp} |
3758 | will jump to, assuming that we have just stopped at a @code{longjmp} | |
3759 | breakpoint. It takes a @code{CORE_ADDR *} as argument, and stores the | |
3760 | target PC value through this pointer. It examines the current state | |
3761 | of the machine as needed, typically by using a manually-determined | |
3762 | offset into the @code{jmp_buf}. (While we might like to get the offset | |
3763 | from the target's @file{jmpbuf.h}, that header file cannot be assumed | |
3764 | to be available when building a cross-debugger.) | |
c906108c | 3765 | |
268e2188 AC |
3766 | @item DEPRECATED_IBM6000_TARGET |
3767 | @findex DEPRECATED_IBM6000_TARGET | |
3768 | Shows that we are configured for an IBM RS/6000 system. This | |
c906108c | 3769 | conditional should be eliminated (FIXME) and replaced by |
1f70da6a | 3770 | feature-specific macros. It was introduced in haste and we are |
c906108c SS |
3771 | repenting at leisure. |
3772 | ||
9742079a EZ |
3773 | @item I386_USE_GENERIC_WATCHPOINTS |
3774 | An x86-based target can define this to use the generic x86 watchpoint | |
3775 | support; see @ref{Algorithms, I386_USE_GENERIC_WATCHPOINTS}. | |
3776 | ||
4a9bb1df UW |
3777 | @item int gdbarch_inner_than (@var{gdbarch}, @var{lhs}, @var{rhs}) |
3778 | @findex gdbarch_inner_than | |
c906108c | 3779 | Returns non-zero if stack address @var{lhs} is inner than (nearer to the |
4a9bb1df UW |
3780 | stack top) stack address @var{rhs}. Let the function return |
3781 | @w{@code{lhs < rhs}} if the target's stack grows downward in memory, or | |
3782 | @w{@code{lhs > rsh}} if the stack grows upward. | |
c906108c | 3783 | |
4a9bb1df | 3784 | @item gdbarch_in_function_epilogue_p (@var{gdbarch}, @var{addr}) |
9e5abb06 | 3785 | @findex gdbarch_in_function_epilogue_p |
4a9bb1df | 3786 | Returns non-zero if the given @var{addr} is in the epilogue of a function. |
9e5abb06 CV |
3787 | The epilogue of a function is defined as the part of a function where |
3788 | the stack frame of the function already has been destroyed up to the | |
3789 | final `return from function call' instruction. | |
3790 | ||
4a9bb1df UW |
3791 | @item int gdbarch_in_solib_return_trampoline (@var{gdbarch}, @var{pc}, @var{name}) |
3792 | @findex gdbarch_in_solib_return_trampoline | |
3793 | Define this function to return nonzero if the program is stopped in the | |
c906108c SS |
3794 | trampoline that returns from a shared library. |
3795 | ||
cfd8ab24 SS |
3796 | @item target_so_ops.in_dynsym_resolve_code (@var{pc}) |
3797 | @findex in_dynsym_resolve_code | |
4a9bb1df | 3798 | Define this to return nonzero if the program is stopped in the |
d4f3574e SS |
3799 | dynamic linker. |
3800 | ||
56caf160 EZ |
3801 | @item SKIP_SOLIB_RESOLVER (@var{pc}) |
3802 | @findex SKIP_SOLIB_RESOLVER | |
d4f3574e SS |
3803 | Define this to evaluate to the (nonzero) address at which execution |
3804 | should continue to get past the dynamic linker's symbol resolution | |
3805 | function. A zero value indicates that it is not important or necessary | |
3806 | to set a breakpoint to get through the dynamic linker and that single | |
3807 | stepping will suffice. | |
3808 | ||
4a9bb1df UW |
3809 | @item CORE_ADDR gdbarch_integer_to_address (@var{gdbarch}, @var{type}, @var{buf}) |
3810 | @findex gdbarch_integer_to_address | |
fc0c74b1 AC |
3811 | @cindex converting integers to addresses |
3812 | Define this when the architecture needs to handle non-pointer to address | |
3813 | conversions specially. Converts that value to an address according to | |
3814 | the current architectures conventions. | |
3815 | ||
3816 | @emph{Pragmatics: When the user copies a well defined expression from | |
3817 | their source code and passes it, as a parameter, to @value{GDBN}'s | |
3818 | @code{print} command, they should get the same value as would have been | |
3819 | computed by the target program. Any deviation from this rule can cause | |
3820 | major confusion and annoyance, and needs to be justified carefully. In | |
3821 | other words, @value{GDBN} doesn't really have the freedom to do these | |
3822 | conversions in clever and useful ways. It has, however, been pointed | |
3823 | out that users aren't complaining about how @value{GDBN} casts integers | |
3824 | to pointers; they are complaining that they can't take an address from a | |
3825 | disassembly listing and give it to @code{x/i}. Adding an architecture | |
4a9bb1df | 3826 | method like @code{gdbarch_integer_to_address} certainly makes it possible for |
fc0c74b1 AC |
3827 | @value{GDBN} to ``get it right'' in all circumstances.} |
3828 | ||
3829 | @xref{Target Architecture Definition, , Pointers Are Not Always | |
3830 | Addresses}. | |
3831 | ||
4a9bb1df UW |
3832 | @item CORE_ADDR gdbarch_pointer_to_address (@var{gdbarch}, @var{type}, @var{buf}) |
3833 | @findex gdbarch_pointer_to_address | |
93e79dbd JB |
3834 | Assume that @var{buf} holds a pointer of type @var{type}, in the |
3835 | appropriate format for the current architecture. Return the byte | |
3836 | address the pointer refers to. | |
3837 | @xref{Target Architecture Definition, , Pointers Are Not Always Addresses}. | |
3838 | ||
4a9bb1df UW |
3839 | @item void gdbarch_register_to_value(@var{gdbarch}, @var{frame}, @var{regnum}, @var{type}, @var{fur}) |
3840 | @findex gdbarch_register_to_value | |
13d01224 AC |
3841 | Convert the raw contents of register @var{regnum} into a value of type |
3842 | @var{type}. | |
4281a42e | 3843 | @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. |
9fb4dd36 | 3844 | |
617073a9 AC |
3845 | @item register_reggroup_p (@var{gdbarch}, @var{regnum}, @var{reggroup}) |
3846 | @findex register_reggroup_p | |
3847 | @cindex register groups | |
3848 | Return non-zero if register @var{regnum} is a member of the register | |
3849 | group @var{reggroup}. | |
3850 | ||
3851 | By default, registers are grouped as follows: | |
3852 | ||
3853 | @table @code | |
3854 | @item float_reggroup | |
3855 | Any register with a valid name and a floating-point type. | |
3856 | @item vector_reggroup | |
3857 | Any register with a valid name and a vector type. | |
3858 | @item general_reggroup | |
3859 | Any register with a valid name and a type other than vector or | |
3860 | floating-point. @samp{float_reggroup}. | |
3861 | @item save_reggroup | |
3862 | @itemx restore_reggroup | |
3863 | @itemx all_reggroup | |
3864 | Any register with a valid name. | |
3865 | @end table | |
3866 | ||
77e7e267 AC |
3867 | @item struct type *register_type (@var{gdbarch}, @var{reg}) |
3868 | @findex register_type | |
1f70da6a SS |
3869 | If defined, return the type of register @var{reg}. |
3870 | @xref{Target Architecture Definition, , Raw and Virtual Register | |
3871 | Representations}. | |
77e7e267 | 3872 | |
9fb4dd36 | 3873 | @item REGISTER_CONVERT_TO_VIRTUAL(@var{reg}, @var{type}, @var{from}, @var{to}) |
56caf160 | 3874 | @findex REGISTER_CONVERT_TO_VIRTUAL |
9fb4dd36 | 3875 | Convert the value of register @var{reg} from its raw form to its virtual |
4281a42e | 3876 | form. |
13d01224 | 3877 | @xref{Target Architecture Definition, , Raw and Virtual Register Representations}. |
9fb4dd36 JB |
3878 | |
3879 | @item REGISTER_CONVERT_TO_RAW(@var{type}, @var{reg}, @var{from}, @var{to}) | |
56caf160 | 3880 | @findex REGISTER_CONVERT_TO_RAW |
9fb4dd36 | 3881 | Convert the value of register @var{reg} from its virtual form to its raw |
4281a42e | 3882 | form. |
13d01224 | 3883 | @xref{Target Architecture Definition, , Raw and Virtual Register Representations}. |
9fb4dd36 | 3884 | |
0ab4b752 MK |
3885 | @item const struct regset *regset_from_core_section (struct gdbarch * @var{gdbarch}, const char * @var{sect_name}, size_t @var{sect_size}) |
3886 | @findex regset_from_core_section | |
3887 | Return the appropriate register set for a core file section with name | |
3888 | @var{sect_name} and size @var{sect_size}. | |
3889 | ||
b0ed3589 | 3890 | @item SOFTWARE_SINGLE_STEP_P() |
56caf160 | 3891 | @findex SOFTWARE_SINGLE_STEP_P |
c906108c | 3892 | Define this as 1 if the target does not have a hardware single-step |
56caf160 | 3893 | mechanism. The macro @code{SOFTWARE_SINGLE_STEP} must also be defined. |
c906108c | 3894 | |
d3e8051b | 3895 | @item SOFTWARE_SINGLE_STEP(@var{signal}, @var{insert_breakpoints_p}) |
56caf160 EZ |
3896 | @findex SOFTWARE_SINGLE_STEP |
3897 | A function that inserts or removes (depending on | |
d3e8051b | 3898 | @var{insert_breakpoints_p}) breakpoints at each possible destinations of |
56caf160 | 3899 | the next instruction. See @file{sparc-tdep.c} and @file{rs6000-tdep.c} |
c906108c SS |
3900 | for examples. |
3901 | ||
e35879db UW |
3902 | @item set_gdbarch_sofun_address_maybe_missing (@var{gdbarch}, @var{set}) |
3903 | @findex set_gdbarch_sofun_address_maybe_missing | |
3904 | Somebody clever observed that, the more actual addresses you have in the | |
3905 | debug information, the more time the linker has to spend relocating | |
3906 | them. So whenever there's some other way the debugger could find the | |
3907 | address it needs, you should omit it from the debug info, to make | |
3908 | linking faster. | |
3909 | ||
3910 | Calling @code{set_gdbarch_sofun_address_maybe_missing} with a non-zero | |
3911 | argument @var{set} indicates that a particular set of hacks of this sort | |
3912 | are in use, affecting @code{N_SO} and @code{N_FUN} entries in stabs-format | |
3913 | debugging information. @code{N_SO} stabs mark the beginning and ending | |
3914 | addresses of compilation units in the text segment. @code{N_FUN} stabs | |
3915 | mark the starts and ends of functions. | |
3916 | ||
3917 | In this case, @value{GDBN} assumes two things: | |
3918 | ||
3919 | @itemize @bullet | |
3920 | @item | |
3921 | @code{N_FUN} stabs have an address of zero. Instead of using those | |
3922 | addresses, you should find the address where the function starts by | |
3923 | taking the function name from the stab, and then looking that up in the | |
3924 | minsyms (the linker/assembler symbol table). In other words, the stab | |
3925 | has the name, and the linker/assembler symbol table is the only place | |
3926 | that carries the address. | |
3927 | ||
3928 | @item | |
3929 | @code{N_SO} stabs have an address of zero, too. You just look at the | |
3930 | @code{N_FUN} stabs that appear before and after the @code{N_SO} stab, and | |
3931 | guess the starting and ending addresses of the compilation unit from them. | |
3932 | @end itemize | |
3933 | ||
4a9bb1df UW |
3934 | @item int gdbarch_pc_regnum (@var{gdbarch}) |
3935 | @findex gdbarch_pc_regnum | |
3936 | If the program counter is kept in a register, then let this function return | |
3937 | the number (greater than or equal to zero) of that register. | |
c906108c | 3938 | |
4a9bb1df UW |
3939 | This should only need to be defined if @code{gdbarch_read_pc} and |
3940 | @code{gdbarch_write_pc} are not defined. | |
2df3850c | 3941 | |
4a9bb1df UW |
3942 | @item int gdbarch_stabs_argument_has_addr (@var{gdbarch}, @var{type}) |
3943 | @findex gdbarch_stabs_argument_has_addr | |
4a9bb1df UW |
3944 | @anchor{gdbarch_stabs_argument_has_addr} Define this function to return |
3945 | nonzero if a function argument of type @var{type} is passed by reference | |
3946 | instead of value. | |
a38c9fe6 | 3947 | |
c906108c | 3948 | @item PROCESS_LINENUMBER_HOOK |
56caf160 | 3949 | @findex PROCESS_LINENUMBER_HOOK |
c906108c SS |
3950 | A hook defined for XCOFF reading. |
3951 | ||
4a9bb1df UW |
3952 | @item gdbarch_ps_regnum (@var{gdbarch} |
3953 | @findex gdbarch_ps_regnum | |
3954 | If defined, this function returns the number of the processor status | |
3955 | register. | |
3956 | (This definition is only used in generic code when parsing "$ps".) | |
c906108c | 3957 | |
4a9bb1df UW |
3958 | @item CORE_ADDR gdbarch_push_dummy_call (@var{gdbarch}, @var{function}, @var{regcache}, @var{bp_addr}, @var{nargs}, @var{args}, @var{sp}, @var{struct_return}, @var{struct_addr}) |
3959 | @findex gdbarch_push_dummy_call | |
4a9bb1df UW |
3960 | @anchor{gdbarch_push_dummy_call} Define this to push the dummy frame's call to |
3961 | the inferior function onto the stack. In addition to pushing @var{nargs}, the | |
3962 | code should push @var{struct_addr} (when @var{struct_return} is non-zero), and | |
3963 | the return address (@var{bp_addr}). | |
c906108c | 3964 | |
86fe4aaa | 3965 | @var{function} is a pointer to a @code{struct value}; on architectures that use |
d4b6d575 RC |
3966 | function descriptors, this contains the function descriptor value. |
3967 | ||
b24da7d0 | 3968 | Returns the updated top-of-stack pointer. |
b81774d8 | 3969 | |
4a9bb1df UW |
3970 | @item CORE_ADDR gdbarch_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}, @var{regcache}) |
3971 | @findex gdbarch_push_dummy_code | |
3972 | @anchor{gdbarch_push_dummy_code} Given a stack based call dummy, push the | |
7043d8dc AC |
3973 | instruction sequence (including space for a breakpoint) to which the |
3974 | called function should return. | |
3975 | ||
3976 | Set @var{bp_addr} to the address at which the breakpoint instruction | |
3977 | should be inserted, @var{real_pc} to the resume address when starting | |
3978 | the call sequence, and return the updated inner-most stack address. | |
3979 | ||
3980 | By default, the stack is grown sufficient to hold a frame-aligned | |
3981 | (@pxref{frame_align}) breakpoint, @var{bp_addr} is set to the address | |
3982 | reserved for that breakpoint, and @var{real_pc} set to @var{funaddr}. | |
3983 | ||
1f70da6a | 3984 | This method replaces @w{@code{gdbarch_call_dummy_location (@var{gdbarch})}}. |
7043d8dc | 3985 | |
4a9bb1df UW |
3986 | @item const char *gdbarch_register_name (@var{gdbarch}, @var{regnr}) |
3987 | @findex gdbarch_register_name | |
3988 | Return the name of register @var{regnr} as a string. May return @code{NULL} | |
3989 | to indicate that @var{regnr} is not a valid register. | |
c906108c | 3990 | |
4a9bb1df UW |
3991 | @item int gdbarch_sdb_reg_to_regnum (@var{gdbarch}, @var{sdb_regnr}) |
3992 | @findex gdbarch_sdb_reg_to_regnum | |
3993 | Use this function to convert sdb register @var{sdb_regnr} into @value{GDBN} | |
3994 | regnum. If not defined, no conversion will be done. | |
c906108c | 3995 | |
963e2bb7 | 3996 | @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 |
3997 | @findex gdbarch_return_value |
3998 | @anchor{gdbarch_return_value} Given a function with a return-value of | |
3999 | type @var{rettype}, return which return-value convention that function | |
4000 | would use. | |
4001 | ||
4002 | @value{GDBN} currently recognizes two function return-value conventions: | |
4003 | @code{RETURN_VALUE_REGISTER_CONVENTION} where the return value is found | |
4004 | in registers; and @code{RETURN_VALUE_STRUCT_CONVENTION} where the return | |
4005 | value is found in memory and the address of that memory location is | |
4006 | passed in as the function's first parameter. | |
4007 | ||
963e2bb7 AC |
4008 | If the register convention is being used, and @var{writebuf} is |
4009 | non-@code{NULL}, also copy the return-value in @var{writebuf} into | |
92ad9cd9 AC |
4010 | @var{regcache}. |
4011 | ||
963e2bb7 | 4012 | If the register convention is being used, and @var{readbuf} is |
92ad9cd9 | 4013 | non-@code{NULL}, also copy the return value from @var{regcache} into |
963e2bb7 | 4014 | @var{readbuf} (@var{regcache} contains a copy of the registers from the |
92ad9cd9 AC |
4015 | just returned function). |
4016 | ||
92ad9cd9 AC |
4017 | @emph{Maintainer note: This method replaces separate predicate, extract, |
4018 | store methods. By having only one method, the logic needed to determine | |
4019 | the return-value convention need only be implemented in one place. If | |
4020 | @value{GDBN} were written in an @sc{oo} language, this method would | |
4021 | instead return an object that knew how to perform the register | |
4022 | return-value extract and store.} | |
4023 | ||
4024 | @emph{Maintainer note: This method does not take a @var{gcc_p} | |
4025 | parameter, and such a parameter should not be added. If an architecture | |
4026 | that requires per-compiler or per-function information be identified, | |
4027 | then the replacement of @var{rettype} with @code{struct value} | |
d3e8051b | 4028 | @var{function} should be pursued.} |
92ad9cd9 AC |
4029 | |
4030 | @emph{Maintainer note: The @var{regcache} parameter limits this methods | |
4031 | to the inner most frame. While replacing @var{regcache} with a | |
4032 | @code{struct frame_info} @var{frame} parameter would remove that | |
4033 | limitation there has yet to be a demonstrated need for such a change.} | |
4034 | ||
4a9bb1df UW |
4035 | @item void gdbarch_skip_permanent_breakpoint (@var{gdbarch}, @var{regcache}) |
4036 | @findex gdbarch_skip_permanent_breakpoint | |
25822942 | 4037 | Advance the inferior's PC past a permanent breakpoint. @value{GDBN} normally |
c2c6d25f JM |
4038 | steps over a breakpoint by removing it, stepping one instruction, and |
4039 | re-inserting the breakpoint. However, permanent breakpoints are | |
4040 | hardwired into the inferior, and can't be removed, so this strategy | |
4a9bb1df UW |
4041 | doesn't work. Calling @code{gdbarch_skip_permanent_breakpoint} adjusts the |
4042 | processor's state so that execution will resume just after the breakpoint. | |
4043 | This function does the right thing even when the breakpoint is in the delay slot | |
c2c6d25f JM |
4044 | of a branch or jump. |
4045 | ||
4a9bb1df UW |
4046 | @item CORE_ADDR gdbarch_skip_prologue (@var{gdbarch}, @var{ip}) |
4047 | @findex gdbarch_skip_prologue | |
4048 | A function that returns the address of the ``real'' code beyond the | |
4049 | function entry prologue found at @var{ip}. | |
c906108c | 4050 | |
4a9bb1df UW |
4051 | @item CORE_ADDR gdbarch_skip_trampoline_code (@var{gdbarch}, @var{frame}, @var{pc}) |
4052 | @findex gdbarch_skip_trampoline_code | |
c906108c | 4053 | If the target machine has trampoline code that sits between callers and |
4a9bb1df | 4054 | the functions being called, then define this function to return a new PC |
c906108c SS |
4055 | that is at the start of the real function. |
4056 | ||
4a9bb1df UW |
4057 | @item int gdbarch_sp_regnum (@var{gdbarch}) |
4058 | @findex gdbarch_sp_regnum | |
4059 | If the stack-pointer is kept in a register, then use this function to return | |
6c0e89ed AC |
4060 | the number (greater than or equal to zero) of that register, or -1 if |
4061 | there is no such register. | |
c906108c | 4062 | |
1f70da6a SS |
4063 | @item int gdbarch_deprecated_fp_regnum (@var{gdbarch}) |
4064 | @findex gdbarch_deprecated_fp_regnum | |
4065 | If the frame pointer is in a register, use this function to return the | |
4066 | number of that register. | |
4067 | ||
4a9bb1df UW |
4068 | @item int gdbarch_stab_reg_to_regnum (@var{gdbarch}, @var{stab_regnr}) |
4069 | @findex gdbarch_stab_reg_to_regnum | |
4070 | Use this function to convert stab register @var{stab_regnr} into @value{GDBN} | |
4071 | regnum. If not defined, no conversion will be done. | |
4072 | ||
c906108c | 4073 | @item SYMBOL_RELOADING_DEFAULT |
56caf160 EZ |
4074 | @findex SYMBOL_RELOADING_DEFAULT |
4075 | The default value of the ``symbol-reloading'' variable. (Never defined in | |
c906108c SS |
4076 | current sources.) |
4077 | ||
c906108c | 4078 | @item TARGET_CHAR_BIT |
56caf160 | 4079 | @findex TARGET_CHAR_BIT |
c906108c SS |
4080 | Number of bits in a char; defaults to 8. |
4081 | ||
4a9bb1df UW |
4082 | @item int gdbarch_char_signed (@var{gdbarch}) |
4083 | @findex gdbarch_char_signed | |
c3d3ce5b JB |
4084 | Non-zero if @code{char} is normally signed on this architecture; zero if |
4085 | it should be unsigned. | |
4086 | ||
4087 | The ISO C standard requires the compiler to treat @code{char} as | |
4088 | equivalent to either @code{signed char} or @code{unsigned char}; any | |
4089 | character in the standard execution set is supposed to be positive. | |
4090 | Most compilers treat @code{char} as signed, but @code{char} is unsigned | |
4091 | on the IBM S/390, RS6000, and PowerPC targets. | |
4092 | ||
4a9bb1df UW |
4093 | @item int gdbarch_double_bit (@var{gdbarch}) |
4094 | @findex gdbarch_double_bit | |
4095 | Number of bits in a double float; defaults to @w{@code{8 * TARGET_CHAR_BIT}}. | |
c906108c | 4096 | |
4a9bb1df UW |
4097 | @item int gdbarch_float_bit (@var{gdbarch}) |
4098 | @findex gdbarch_float_bit | |
4099 | Number of bits in a float; defaults to @w{@code{4 * TARGET_CHAR_BIT}}. | |
ac9a91a7 | 4100 | |
4a9bb1df UW |
4101 | @item int gdbarch_int_bit (@var{gdbarch}) |
4102 | @findex gdbarch_int_bit | |
4103 | Number of bits in an integer; defaults to @w{@code{4 * TARGET_CHAR_BIT}}. | |
c906108c | 4104 | |
4a9bb1df UW |
4105 | @item int gdbarch_long_bit (@var{gdbarch}) |
4106 | @findex gdbarch_long_bit | |
4107 | Number of bits in a long integer; defaults to @w{@code{4 * TARGET_CHAR_BIT}}. | |
c906108c | 4108 | |
4a9bb1df UW |
4109 | @item int gdbarch_long_double_bit (@var{gdbarch}) |
4110 | @findex gdbarch_long_double_bit | |
c906108c | 4111 | Number of bits in a long double float; |
4a9bb1df UW |
4112 | defaults to @w{@code{2 * gdbarch_double_bit (@var{gdbarch})}}. |
4113 | ||
4114 | @item int gdbarch_long_long_bit (@var{gdbarch}) | |
4115 | @findex gdbarch_long_long_bit | |
4116 | Number of bits in a long long integer; defaults to | |
4117 | @w{@code{2 * gdbarch_long_bit (@var{gdbarch})}}. | |
4118 | ||
4119 | @item int gdbarch_ptr_bit (@var{gdbarch}) | |
4120 | @findex gdbarch_ptr_bit | |
4121 | Number of bits in a pointer; defaults to | |
4122 | @w{@code{gdbarch_int_bit (@var{gdbarch})}}. | |
4123 | ||
4124 | @item int gdbarch_short_bit (@var{gdbarch}) | |
4125 | @findex gdbarch_short_bit | |
4126 | Number of bits in a short integer; defaults to @w{@code{2 * TARGET_CHAR_BIT}}. | |
4127 | ||
4128 | @item CORE_ADDR gdbarch_read_pc (@var{gdbarch}, @var{regcache}) | |
4129 | @findex gdbarch_read_pc | |
4130 | @itemx gdbarch_write_pc (@var{gdbarch}, @var{regcache}, @var{val}) | |
4131 | @findex gdbarch_write_pc | |
4132 | @anchor{gdbarch_write_pc} | |
56caf160 EZ |
4133 | @itemx TARGET_READ_SP |
4134 | @findex TARGET_READ_SP | |
56caf160 EZ |
4135 | @itemx TARGET_READ_FP |
4136 | @findex TARGET_READ_FP | |
4a9bb1df UW |
4137 | @findex gdbarch_read_pc |
4138 | @findex gdbarch_write_pc | |
56caf160 | 4139 | @findex read_sp |
56caf160 | 4140 | @findex read_fp |
4a9bb1df UW |
4141 | @anchor{TARGET_READ_SP} These change the behavior of @code{gdbarch_read_pc}, |
4142 | @code{gdbarch_write_pc}, and @code{read_sp}. For most targets, these may be | |
9c8dbfa9 AC |
4143 | left undefined. @value{GDBN} will call the read and write register |
4144 | functions with the relevant @code{_REGNUM} argument. | |
c906108c | 4145 | |
4a9bb1df UW |
4146 | These macros and functions are useful when a target keeps one of these |
4147 | registers in a hard to get at place; for example, part in a segment register | |
4148 | and part in an ordinary register. | |
c906108c | 4149 | |
4a9bb1df | 4150 | @xref{gdbarch_unwind_sp}, which replaces @code{TARGET_READ_SP}. |
a9e5fdc2 | 4151 | |
4a9bb1df UW |
4152 | @item void gdbarch_virtual_frame_pointer (@var{gdbarch}, @var{pc}, @var{frame_regnum}, @var{frame_offset}) |
4153 | @findex gdbarch_virtual_frame_pointer | |
1f70da6a SS |
4154 | Returns a @code{(@var{register}, @var{offset})} pair representing the virtual |
4155 | frame pointer in use at the code address @var{pc}. If virtual frame | |
4156 | pointers are not used, a default definition simply returns | |
4157 | @code{gdbarch_deprecated_fp_regnum} (or @code{gdbarch_sp_regnum}, if | |
4158 | no frame pointer is defined), with an offset of zero. | |
4159 | ||
4160 | @c need to explain virtual frame pointers, they are recorded in agent expressions | |
4161 | @c for tracepoints | |
c906108c | 4162 | |
9742079a EZ |
4163 | @item TARGET_HAS_HARDWARE_WATCHPOINTS |
4164 | If non-zero, the target has support for hardware-assisted | |
4165 | watchpoints. @xref{Algorithms, watchpoints}, for more details and | |
4166 | other related macros. | |
4167 | ||
4a9bb1df UW |
4168 | @item int gdbarch_print_insn (@var{gdbarch}, @var{vma}, @var{info}) |
4169 | @findex gdbarch_print_insn | |
7ccaa899 | 4170 | This is the function used by @value{GDBN} to print an assembly |
4a9bb1df | 4171 | instruction. It prints the instruction at address @var{vma} in |
1f70da6a SS |
4172 | debugged memory and returns the length of the instruction, in bytes. |
4173 | This usually points to a function in the @code{opcodes} library | |
4174 | (@pxref{Support Libraries, ,Opcodes}). @var{info} is a structure (of | |
4175 | type @code{disassemble_info}) defined in the header file | |
4176 | @file{include/dis-asm.h}, and used to pass information to the | |
4177 | instruction decoding routine. | |
7ccaa899 | 4178 | |
669fac23 DJ |
4179 | @item frame_id gdbarch_dummy_id (@var{gdbarch}, @var{frame}) |
4180 | @findex gdbarch_dummy_id | |
4181 | @anchor{gdbarch_dummy_id} Given @var{frame} return a @w{@code{struct | |
4a9bb1df | 4182 | frame_id}} that uniquely identifies an inferior function call's dummy |
b24da7d0 | 4183 | frame. The value returned must match the dummy frame stack value |
669fac23 | 4184 | previously saved by @code{call_function_by_hand}. |
6314f104 | 4185 | |
4a9bb1df UW |
4186 | @item void gdbarch_value_to_register (@var{gdbarch}, @var{frame}, @var{type}, @var{buf}) |
4187 | @findex gdbarch_value_to_register | |
4188 | Convert a value of type @var{type} into the raw contents of a register. | |
13d01224 AC |
4189 | @xref{Target Architecture Definition, , Using Different Register and Memory Data Representations}. |
4190 | ||
c906108c SS |
4191 | @end table |
4192 | ||
4193 | Motorola M68K target conditionals. | |
4194 | ||
56caf160 | 4195 | @ftable @code |
c906108c SS |
4196 | @item BPT_VECTOR |
4197 | Define this to be the 4-bit location of the breakpoint trap vector. If | |
4198 | not defined, it will default to @code{0xf}. | |
4199 | ||
4200 | @item REMOTE_BPT_VECTOR | |
4201 | Defaults to @code{1}. | |
a23a7bf1 | 4202 | |
56caf160 | 4203 | @end ftable |
c906108c | 4204 | |
b6fd0dfb | 4205 | @node Adding a New Target |
c906108c SS |
4206 | @section Adding a New Target |
4207 | ||
56caf160 | 4208 | @cindex adding a target |
af6c57ea | 4209 | The following files add a target to @value{GDBN}: |
c906108c SS |
4210 | |
4211 | @table @file | |
f0323ca0 | 4212 | @cindex target dependent files |
c906108c | 4213 | |
c906108c SS |
4214 | @item gdb/@var{ttt}-tdep.c |
4215 | Contains any miscellaneous code required for this target machine. On | |
1f70da6a | 4216 | some machines it doesn't exist at all. |
c906108c | 4217 | |
af6c57ea AC |
4218 | @item gdb/@var{arch}-tdep.c |
4219 | @itemx gdb/@var{arch}-tdep.h | |
1f70da6a SS |
4220 | This is required to describe the basic layout of the target machine's |
4221 | processor chip (registers, stack, etc.). It can be shared among many | |
4222 | targets that use the same processor architecture. | |
af6c57ea | 4223 | |
c906108c SS |
4224 | @end table |
4225 | ||
1f70da6a SS |
4226 | (Target header files such as |
4227 | @file{gdb/config/@var{arch}/tm-@var{ttt}.h}, | |
4228 | @file{gdb/config/@var{arch}/tm-@var{arch}.h}, and | |
4229 | @file{config/tm-@var{os}.h} are no longer used.) | |
c906108c | 4230 | |
123dc839 DJ |
4231 | @node Target Descriptions |
4232 | @chapter Target Descriptions | |
4233 | @cindex target descriptions | |
4234 | ||
4235 | The target architecture definition (@pxref{Target Architecture Definition}) | |
4236 | contains @value{GDBN}'s hard-coded knowledge about an architecture. For | |
4237 | some platforms, it is handy to have more flexible knowledge about a specific | |
4238 | instance of the architecture---for instance, a processor or development board. | |
4239 | @dfn{Target descriptions} provide a mechanism for the user to tell @value{GDBN} | |
4240 | more about what their target supports, or for the target to tell @value{GDBN} | |
4241 | directly. | |
4242 | ||
4243 | For details on writing, automatically supplying, and manually selecting | |
4244 | target descriptions, see @ref{Target Descriptions, , , gdb, | |
4245 | Debugging with @value{GDBN}}. This section will cover some related | |
4246 | topics about the @value{GDBN} internals. | |
4247 | ||
4248 | @menu | |
4249 | * Target Descriptions Implementation:: | |
4250 | * Adding Target Described Register Support:: | |
4251 | @end menu | |
4252 | ||
4253 | @node Target Descriptions Implementation | |
4254 | @section Target Descriptions Implementation | |
4255 | @cindex target descriptions, implementation | |
4256 | ||
4257 | Before @value{GDBN} connects to a new target, or runs a new program on | |
4258 | an existing target, it discards any existing target description and | |
4259 | reverts to a default gdbarch. Then, after connecting, it looks for a | |
4260 | new target description by calling @code{target_find_description}. | |
4261 | ||
4262 | A description may come from a user specified file (XML), the remote | |
4263 | @samp{qXfer:features:read} packet (also XML), or from any custom | |
4264 | @code{to_read_description} routine in the target vector. For instance, | |
4265 | the remote target supports guessing whether a MIPS target is 32-bit or | |
4266 | 64-bit based on the size of the @samp{g} packet. | |
4267 | ||
4268 | If any target description is found, @value{GDBN} creates a new gdbarch | |
4269 | incorporating the description by calling @code{gdbarch_update_p}. Any | |
4270 | @samp{<architecture>} element is handled first, to determine which | |
4271 | architecture's gdbarch initialization routine is called to create the | |
4272 | new architecture. Then the initialization routine is called, and has | |
4273 | a chance to adjust the constructed architecture based on the contents | |
4274 | of the target description. For instance, it can recognize any | |
4275 | properties set by a @code{to_read_description} routine. Also | |
4276 | see @ref{Adding Target Described Register Support}. | |
4277 | ||
4278 | @node Adding Target Described Register Support | |
4279 | @section Adding Target Described Register Support | |
4280 | @cindex target descriptions, adding register support | |
4281 | ||
4282 | Target descriptions can report additional registers specific to an | |
4283 | instance of the target. But it takes a little work in the architecture | |
4284 | specific routines to support this. | |
4285 | ||
4286 | A target description must either have no registers or a complete | |
4287 | set---this avoids complexity in trying to merge standard registers | |
4288 | with the target defined registers. It is the architecture's | |
4289 | responsibility to validate that a description with registers has | |
4290 | everything it needs. To keep architecture code simple, the same | |
4291 | mechanism is used to assign fixed internal register numbers to | |
4292 | standard registers. | |
4293 | ||
4294 | If @code{tdesc_has_registers} returns 1, the description contains | |
4295 | registers. The architecture's @code{gdbarch_init} routine should: | |
4296 | ||
4297 | @itemize @bullet | |
4298 | ||
4299 | @item | |
4300 | Call @code{tdesc_data_alloc} to allocate storage, early, before | |
4301 | searching for a matching gdbarch or allocating a new one. | |
4302 | ||
4303 | @item | |
4304 | Use @code{tdesc_find_feature} to locate standard features by name. | |
4305 | ||
4306 | @item | |
4307 | Use @code{tdesc_numbered_register} and @code{tdesc_numbered_register_choices} | |
4308 | to locate the expected registers in the standard features. | |
4309 | ||
4310 | @item | |
4311 | Return @code{NULL} if a required feature is missing, or if any standard | |
4312 | feature is missing expected registers. This will produce a warning that | |
4313 | the description was incomplete. | |
4314 | ||
4315 | @item | |
4316 | Free the allocated data before returning, unless @code{tdesc_use_registers} | |
4317 | is called. | |
4318 | ||
4319 | @item | |
4320 | Call @code{set_gdbarch_num_regs} as usual, with a number higher than any | |
4321 | fixed number passed to @code{tdesc_numbered_register}. | |
4322 | ||
4323 | @item | |
4324 | Call @code{tdesc_use_registers} after creating a new gdbarch, before | |
4325 | returning it. | |
4326 | ||
4327 | @end itemize | |
4328 | ||
4329 | After @code{tdesc_use_registers} has been called, the architecture's | |
4330 | @code{register_name}, @code{register_type}, and @code{register_reggroup_p} | |
4331 | routines will not be called; that information will be taken from | |
4332 | the target description. @code{num_regs} may be increased to account | |
4333 | for any additional registers in the description. | |
4334 | ||
4335 | Pseudo-registers require some extra care: | |
4336 | ||
4337 | @itemize @bullet | |
4338 | ||
4339 | @item | |
4340 | Using @code{tdesc_numbered_register} allows the architecture to give | |
4341 | constant register numbers to standard architectural registers, e.g.@: | |
4342 | as an @code{enum} in @file{@var{arch}-tdep.h}. But because | |
4343 | pseudo-registers are always numbered above @code{num_regs}, | |
4344 | which may be increased by the description, constant numbers | |
4345 | can not be used for pseudos. They must be numbered relative to | |
4346 | @code{num_regs} instead. | |
4347 | ||
4348 | @item | |
4349 | The description will not describe pseudo-registers, so the | |
4350 | architecture must call @code{set_tdesc_pseudo_register_name}, | |
4351 | @code{set_tdesc_pseudo_register_type}, and | |
4352 | @code{set_tdesc_pseudo_register_reggroup_p} to supply routines | |
4353 | describing pseudo registers. These routines will be passed | |
4354 | internal register numbers, so the same routines used for the | |
4355 | gdbarch equivalents are usually suitable. | |
4356 | ||
4357 | @end itemize | |
4358 | ||
4359 | ||
c906108c SS |
4360 | @node Target Vector Definition |
4361 | ||
4362 | @chapter Target Vector Definition | |
56caf160 | 4363 | @cindex target vector |
c906108c | 4364 | |
56caf160 EZ |
4365 | The target vector defines the interface between @value{GDBN}'s |
4366 | abstract handling of target systems, and the nitty-gritty code that | |
4367 | actually exercises control over a process or a serial port. | |
4368 | @value{GDBN} includes some 30-40 different target vectors; however, | |
4369 | each configuration of @value{GDBN} includes only a few of them. | |
c906108c | 4370 | |
52bb452f DJ |
4371 | @menu |
4372 | * Managing Execution State:: | |
4373 | * Existing Targets:: | |
4374 | @end menu | |
4375 | ||
4376 | @node Managing Execution State | |
4377 | @section Managing Execution State | |
4378 | @cindex execution state | |
4379 | ||
4380 | A target vector can be completely inactive (not pushed on the target | |
4381 | stack), active but not running (pushed, but not connected to a fully | |
4382 | manifested inferior), or completely active (pushed, with an accessible | |
4383 | inferior). Most targets are only completely inactive or completely | |
d3e8051b | 4384 | active, but some support persistent connections to a target even |
52bb452f DJ |
4385 | when the target has exited or not yet started. |
4386 | ||
4387 | For example, connecting to the simulator using @code{target sim} does | |
4388 | not create a running program. Neither registers nor memory are | |
4389 | accessible until @code{run}. Similarly, after @code{kill}, the | |
4390 | program can not continue executing. But in both cases @value{GDBN} | |
4391 | remains connected to the simulator, and target-specific commands | |
4392 | are directed to the simulator. | |
4393 | ||
4394 | A target which only supports complete activation should push itself | |
4395 | onto the stack in its @code{to_open} routine (by calling | |
4396 | @code{push_target}), and unpush itself from the stack in its | |
4397 | @code{to_mourn_inferior} routine (by calling @code{unpush_target}). | |
4398 | ||
4399 | A target which supports both partial and complete activation should | |
4400 | still call @code{push_target} in @code{to_open}, but not call | |
4401 | @code{unpush_target} in @code{to_mourn_inferior}. Instead, it should | |
4402 | call either @code{target_mark_running} or @code{target_mark_exited} | |
4403 | in its @code{to_open}, depending on whether the target is fully active | |
4404 | after connection. It should also call @code{target_mark_running} any | |
4405 | time the inferior becomes fully active (e.g.@: in | |
4406 | @code{to_create_inferior} and @code{to_attach}), and | |
4407 | @code{target_mark_exited} when the inferior becomes inactive (in | |
4408 | @code{to_mourn_inferior}). The target should also make sure to call | |
4409 | @code{target_mourn_inferior} from its @code{to_kill}, to return the | |
4410 | target to inactive state. | |
4411 | ||
4412 | @node Existing Targets | |
4413 | @section Existing Targets | |
4414 | @cindex targets | |
4415 | ||
4416 | @subsection File Targets | |
c906108c SS |
4417 | |
4418 | Both executables and core files have target vectors. | |
4419 | ||
52bb452f | 4420 | @subsection Standard Protocol and Remote Stubs |
c906108c | 4421 | |
56caf160 EZ |
4422 | @value{GDBN}'s file @file{remote.c} talks a serial protocol to code |
4423 | that runs in the target system. @value{GDBN} provides several sample | |
4424 | @dfn{stubs} that can be integrated into target programs or operating | |
1f70da6a SS |
4425 | systems for this purpose; they are named @file{@var{cpu}-stub.c}. Many |
4426 | operating systems, embedded targets, emulators, and simulators already | |
4427 | have a GDB stub built into them, and maintenance of the remote | |
4428 | protocol must be careful to preserve compatibility. | |
c906108c | 4429 | |
56caf160 EZ |
4430 | The @value{GDBN} user's manual describes how to put such a stub into |
4431 | your target code. What follows is a discussion of integrating the | |
4432 | SPARC stub into a complicated operating system (rather than a simple | |
4433 | program), by Stu Grossman, the author of this stub. | |
c906108c SS |
4434 | |
4435 | The trap handling code in the stub assumes the following upon entry to | |
56caf160 | 4436 | @code{trap_low}: |
c906108c SS |
4437 | |
4438 | @enumerate | |
56caf160 EZ |
4439 | @item |
4440 | %l1 and %l2 contain pc and npc respectively at the time of the trap; | |
c906108c | 4441 | |
56caf160 EZ |
4442 | @item |
4443 | traps are disabled; | |
c906108c | 4444 | |
56caf160 EZ |
4445 | @item |
4446 | you are in the correct trap window. | |
c906108c SS |
4447 | @end enumerate |
4448 | ||
4449 | As long as your trap handler can guarantee those conditions, then there | |
56caf160 | 4450 | is no reason why you shouldn't be able to ``share'' traps with the stub. |
c906108c SS |
4451 | The stub has no requirement that it be jumped to directly from the |
4452 | hardware trap vector. That is why it calls @code{exceptionHandler()}, | |
4453 | which is provided by the external environment. For instance, this could | |
56caf160 | 4454 | set up the hardware traps to actually execute code which calls the stub |
c906108c SS |
4455 | first, and then transfers to its own trap handler. |
4456 | ||
4457 | For the most point, there probably won't be much of an issue with | |
56caf160 | 4458 | ``sharing'' traps, as the traps we use are usually not used by the kernel, |
c906108c SS |
4459 | and often indicate unrecoverable error conditions. Anyway, this is all |
4460 | controlled by a table, and is trivial to modify. The most important | |
4461 | trap for us is for @code{ta 1}. Without that, we can't single step or | |
4462 | do breakpoints. Everything else is unnecessary for the proper operation | |
4463 | of the debugger/stub. | |
4464 | ||
4465 | From reading the stub, it's probably not obvious how breakpoints work. | |
25822942 | 4466 | They are simply done by deposit/examine operations from @value{GDBN}. |
c906108c | 4467 | |
52bb452f | 4468 | @subsection ROM Monitor Interface |
c906108c | 4469 | |
52bb452f | 4470 | @subsection Custom Protocols |
c906108c | 4471 | |
52bb452f | 4472 | @subsection Transport Layer |
c906108c | 4473 | |
52bb452f | 4474 | @subsection Builtin Simulator |
c906108c SS |
4475 | |
4476 | ||
4477 | @node Native Debugging | |
4478 | ||
4479 | @chapter Native Debugging | |
56caf160 | 4480 | @cindex native debugging |
c906108c | 4481 | |
25822942 | 4482 | Several files control @value{GDBN}'s configuration for native support: |
c906108c SS |
4483 | |
4484 | @table @file | |
56caf160 | 4485 | @vindex NATDEPFILES |
c906108c | 4486 | @item gdb/config/@var{arch}/@var{xyz}.mh |
7fd60527 | 4487 | Specifies Makefile fragments needed by a @emph{native} configuration on |
c906108c SS |
4488 | machine @var{xyz}. In particular, this lists the required |
4489 | native-dependent object files, by defining @samp{NATDEPFILES=@dots{}}. | |
4490 | Also specifies the header file which describes native support on | |
4491 | @var{xyz}, by defining @samp{NAT_FILE= nm-@var{xyz}.h}. You can also | |
4492 | define @samp{NAT_CFLAGS}, @samp{NAT_ADD_FILES}, @samp{NAT_CLIBS}, | |
3d0bb823 | 4493 | @samp{NAT_CDEPS}, @samp{NAT_GENERATED_FILES}, etc.; see @file{Makefile.in}. |
c906108c | 4494 | |
7fd60527 AC |
4495 | @emph{Maintainer's note: The @file{.mh} suffix is because this file |
4496 | originally contained @file{Makefile} fragments for hosting @value{GDBN} | |
4497 | on machine @var{xyz}. While the file is no longer used for this | |
937f164b | 4498 | purpose, the @file{.mh} suffix remains. Perhaps someone will |
7fd60527 AC |
4499 | eventually rename these fragments so that they have a @file{.mn} |
4500 | suffix.} | |
4501 | ||
c906108c | 4502 | @item gdb/config/@var{arch}/nm-@var{xyz}.h |
56caf160 | 4503 | (@file{nm.h} is a link to this file, created by @code{configure}). Contains C |
c906108c SS |
4504 | macro definitions describing the native system environment, such as |
4505 | child process control and core file support. | |
4506 | ||
4507 | @item gdb/@var{xyz}-nat.c | |
4508 | Contains any miscellaneous C code required for this native support of | |
4509 | this machine. On some machines it doesn't exist at all. | |
c906108c SS |
4510 | @end table |
4511 | ||
4512 | There are some ``generic'' versions of routines that can be used by | |
4513 | various systems. These can be customized in various ways by macros | |
4514 | defined in your @file{nm-@var{xyz}.h} file. If these routines work for | |
4515 | the @var{xyz} host, you can just include the generic file's name (with | |
4516 | @samp{.o}, not @samp{.c}) in @code{NATDEPFILES}. | |
4517 | ||
4518 | Otherwise, if your machine needs custom support routines, you will need | |
4519 | to write routines that perform the same functions as the generic file. | |
56caf160 | 4520 | Put them into @file{@var{xyz}-nat.c}, and put @file{@var{xyz}-nat.o} |
c906108c SS |
4521 | into @code{NATDEPFILES}. |
4522 | ||
4523 | @table @file | |
c906108c SS |
4524 | @item inftarg.c |
4525 | This contains the @emph{target_ops vector} that supports Unix child | |
4526 | processes on systems which use ptrace and wait to control the child. | |
4527 | ||
4528 | @item procfs.c | |
4529 | This contains the @emph{target_ops vector} that supports Unix child | |
4530 | processes on systems which use /proc to control the child. | |
4531 | ||
4532 | @item fork-child.c | |
56caf160 EZ |
4533 | This does the low-level grunge that uses Unix system calls to do a ``fork |
4534 | and exec'' to start up a child process. | |
c906108c SS |
4535 | |
4536 | @item infptrace.c | |
4537 | This is the low level interface to inferior processes for systems using | |
4538 | the Unix @code{ptrace} call in a vanilla way. | |
c906108c SS |
4539 | @end table |
4540 | ||
4541 | @section Native core file Support | |
56caf160 | 4542 | @cindex native core files |
c906108c SS |
4543 | |
4544 | @table @file | |
56caf160 | 4545 | @findex fetch_core_registers |
c906108c SS |
4546 | @item core-aout.c::fetch_core_registers() |
4547 | Support for reading registers out of a core file. This routine calls | |
4548 | @code{register_addr()}, see below. Now that BFD is used to read core | |
4549 | files, virtually all machines should use @code{core-aout.c}, and should | |
4550 | just provide @code{fetch_core_registers} in @code{@var{xyz}-nat.c} (or | |
4551 | @code{REGISTER_U_ADDR} in @code{nm-@var{xyz}.h}). | |
4552 | ||
4553 | @item core-aout.c::register_addr() | |
4554 | If your @code{nm-@var{xyz}.h} file defines the macro | |
4555 | @code{REGISTER_U_ADDR(addr, blockend, regno)}, it should be defined to | |
25822942 | 4556 | set @code{addr} to the offset within the @samp{user} struct of @value{GDBN} |
c906108c SS |
4557 | register number @code{regno}. @code{blockend} is the offset within the |
4558 | ``upage'' of @code{u.u_ar0}. If @code{REGISTER_U_ADDR} is defined, | |
4559 | @file{core-aout.c} will define the @code{register_addr()} function and | |
4560 | use the macro in it. If you do not define @code{REGISTER_U_ADDR}, but | |
4561 | you are using the standard @code{fetch_core_registers()}, you will need | |
4562 | to define your own version of @code{register_addr()}, put it into your | |
4563 | @code{@var{xyz}-nat.c} file, and be sure @code{@var{xyz}-nat.o} is in | |
4564 | the @code{NATDEPFILES} list. If you have your own | |
4565 | @code{fetch_core_registers()}, you may not need a separate | |
4566 | @code{register_addr()}. Many custom @code{fetch_core_registers()} | |
4567 | implementations simply locate the registers themselves.@refill | |
c906108c SS |
4568 | @end table |
4569 | ||
25822942 | 4570 | When making @value{GDBN} run native on a new operating system, to make it |
c906108c SS |
4571 | possible to debug core files, you will need to either write specific |
4572 | code for parsing your OS's core files, or customize | |
4573 | @file{bfd/trad-core.c}. First, use whatever @code{#include} files your | |
4574 | machine uses to define the struct of registers that is accessible | |
4575 | (possibly in the u-area) in a core file (rather than | |
4576 | @file{machine/reg.h}), and an include file that defines whatever header | |
c1468174 | 4577 | exists on a core file (e.g., the u-area or a @code{struct core}). Then |
56caf160 | 4578 | modify @code{trad_unix_core_file_p} to use these values to set up the |
c906108c SS |
4579 | section information for the data segment, stack segment, any other |
4580 | segments in the core file (perhaps shared library contents or control | |
4581 | information), ``registers'' segment, and if there are two discontiguous | |
c1468174 | 4582 | sets of registers (e.g., integer and float), the ``reg2'' segment. This |
c906108c SS |
4583 | section information basically delimits areas in the core file in a |
4584 | standard way, which the section-reading routines in BFD know how to seek | |
4585 | around in. | |
4586 | ||
25822942 | 4587 | Then back in @value{GDBN}, you need a matching routine called |
56caf160 | 4588 | @code{fetch_core_registers}. If you can use the generic one, it's in |
c906108c SS |
4589 | @file{core-aout.c}; if not, it's in your @file{@var{xyz}-nat.c} file. |
4590 | It will be passed a char pointer to the entire ``registers'' segment, | |
4591 | its length, and a zero; or a char pointer to the entire ``regs2'' | |
4592 | segment, its length, and a 2. The routine should suck out the supplied | |
25822942 | 4593 | register values and install them into @value{GDBN}'s ``registers'' array. |
c906108c SS |
4594 | |
4595 | If your system uses @file{/proc} to control processes, and uses ELF | |
4596 | format core files, then you may be able to use the same routines for | |
4597 | reading the registers out of processes and out of core files. | |
4598 | ||
4599 | @section ptrace | |
4600 | ||
4601 | @section /proc | |
4602 | ||
4603 | @section win32 | |
4604 | ||
4605 | @section shared libraries | |
4606 | ||
4607 | @section Native Conditionals | |
56caf160 | 4608 | @cindex native conditionals |
c906108c | 4609 | |
56caf160 EZ |
4610 | When @value{GDBN} is configured and compiled, various macros are |
4611 | defined or left undefined, to control compilation when the host and | |
4612 | target systems are the same. These macros should be defined (or left | |
4613 | undefined) in @file{nm-@var{system}.h}. | |
c906108c | 4614 | |
1f6d4158 AC |
4615 | @table @code |
4616 | ||
9742079a EZ |
4617 | @item I386_USE_GENERIC_WATCHPOINTS |
4618 | An x86-based machine can define this to use the generic x86 watchpoint | |
4619 | support; see @ref{Algorithms, I386_USE_GENERIC_WATCHPOINTS}. | |
4620 | ||
c906108c | 4621 | @item PROC_NAME_FMT |
56caf160 | 4622 | @findex PROC_NAME_FMT |
c906108c SS |
4623 | Defines the format for the name of a @file{/proc} device. Should be |
4624 | defined in @file{nm.h} @emph{only} in order to override the default | |
4625 | definition in @file{procfs.c}. | |
4626 | ||
990f9fe3 | 4627 | @item SOLIB_ADD (@var{filename}, @var{from_tty}, @var{targ}, @var{readsyms}) |
56caf160 | 4628 | @findex SOLIB_ADD |
c906108c | 4629 | Define this to expand into an expression that will cause the symbols in |
990f9fe3 FF |
4630 | @var{filename} to be added to @value{GDBN}'s symbol table. If |
4631 | @var{readsyms} is zero symbols are not read but any necessary low level | |
4632 | processing for @var{filename} is still done. | |
c906108c SS |
4633 | |
4634 | @item SOLIB_CREATE_INFERIOR_HOOK | |
56caf160 | 4635 | @findex SOLIB_CREATE_INFERIOR_HOOK |
c906108c SS |
4636 | Define this to expand into any shared-library-relocation code that you |
4637 | want to be run just after the child process has been forked. | |
4638 | ||
4639 | @item START_INFERIOR_TRAPS_EXPECTED | |
56caf160 EZ |
4640 | @findex START_INFERIOR_TRAPS_EXPECTED |
4641 | When starting an inferior, @value{GDBN} normally expects to trap | |
4642 | twice; once when | |
c906108c SS |
4643 | the shell execs, and once when the program itself execs. If the actual |
4644 | number of traps is something other than 2, then define this macro to | |
4645 | expand into the number expected. | |
4646 | ||
c906108c SS |
4647 | @end table |
4648 | ||
c906108c SS |
4649 | @node Support Libraries |
4650 | ||
4651 | @chapter Support Libraries | |
4652 | ||
4653 | @section BFD | |
56caf160 | 4654 | @cindex BFD library |
c906108c | 4655 | |
25822942 | 4656 | BFD provides support for @value{GDBN} in several ways: |
c906108c SS |
4657 | |
4658 | @table @emph | |
c906108c SS |
4659 | @item identifying executable and core files |
4660 | BFD will identify a variety of file types, including a.out, coff, and | |
4661 | several variants thereof, as well as several kinds of core files. | |
4662 | ||
4663 | @item access to sections of files | |
4664 | BFD parses the file headers to determine the names, virtual addresses, | |
4665 | sizes, and file locations of all the various named sections in files | |
56caf160 EZ |
4666 | (such as the text section or the data section). @value{GDBN} simply |
4667 | calls BFD to read or write section @var{x} at byte offset @var{y} for | |
4668 | length @var{z}. | |
c906108c SS |
4669 | |
4670 | @item specialized core file support | |
4671 | BFD provides routines to determine the failing command name stored in a | |
4672 | core file, the signal with which the program failed, and whether a core | |
56caf160 | 4673 | file matches (i.e.@: could be a core dump of) a particular executable |
c906108c SS |
4674 | file. |
4675 | ||
4676 | @item locating the symbol information | |
25822942 DB |
4677 | @value{GDBN} uses an internal interface of BFD to determine where to find the |
4678 | symbol information in an executable file or symbol-file. @value{GDBN} itself | |
c906108c | 4679 | handles the reading of symbols, since BFD does not ``understand'' debug |
25822942 | 4680 | symbols, but @value{GDBN} uses BFD's cached information to find the symbols, |
c906108c | 4681 | string table, etc. |
c906108c SS |
4682 | @end table |
4683 | ||
4684 | @section opcodes | |
56caf160 | 4685 | @cindex opcodes library |
c906108c | 4686 | |
25822942 | 4687 | The opcodes library provides @value{GDBN}'s disassembler. (It's a separate |
c906108c SS |
4688 | library because it's also used in binutils, for @file{objdump}). |
4689 | ||
4690 | @section readline | |
86f04699 EZ |
4691 | @cindex readline library |
4692 | The @code{readline} library provides a set of functions for use by applications | |
4693 | that allow users to edit command lines as they are typed in. | |
c906108c SS |
4694 | |
4695 | @section libiberty | |
1eb288ea EZ |
4696 | @cindex @code{libiberty} library |
4697 | ||
4698 | The @code{libiberty} library provides a set of functions and features | |
4699 | that integrate and improve on functionality found in modern operating | |
4700 | systems. Broadly speaking, such features can be divided into three | |
4701 | groups: supplemental functions (functions that may be missing in some | |
4702 | environments and operating systems), replacement functions (providing | |
4703 | a uniform and easier to use interface for commonly used standard | |
4704 | functions), and extensions (which provide additional functionality | |
4705 | beyond standard functions). | |
4706 | ||
4707 | @value{GDBN} uses various features provided by the @code{libiberty} | |
4708 | library, for instance the C@t{++} demangler, the @acronym{IEEE} | |
4709 | floating format support functions, the input options parser | |
4710 | @samp{getopt}, the @samp{obstack} extension, and other functions. | |
4711 | ||
4712 | @subsection @code{obstacks} in @value{GDBN} | |
4713 | @cindex @code{obstacks} | |
4714 | ||
4715 | The obstack mechanism provides a convenient way to allocate and free | |
4716 | chunks of memory. Each obstack is a pool of memory that is managed | |
4717 | like a stack. Objects (of any nature, size and alignment) are | |
4718 | allocated and freed in a @acronym{LIFO} fashion on an obstack (see | |
d3e8051b | 4719 | @code{libiberty}'s documentation for a more detailed explanation of |
1eb288ea EZ |
4720 | @code{obstacks}). |
4721 | ||
4722 | The most noticeable use of the @code{obstacks} in @value{GDBN} is in | |
4723 | object files. There is an obstack associated with each internal | |
4724 | representation of an object file. Lots of things get allocated on | |
4725 | these @code{obstacks}: dictionary entries, blocks, blockvectors, | |
4726 | symbols, minimal symbols, types, vectors of fundamental types, class | |
4727 | fields of types, object files section lists, object files section | |
d3e8051b | 4728 | offset lists, line tables, symbol tables, partial symbol tables, |
1eb288ea EZ |
4729 | string tables, symbol table private data, macros tables, debug |
4730 | information sections and entries, import and export lists (som), | |
4731 | unwind information (hppa), dwarf2 location expressions data. Plus | |
4732 | various strings such as directory names strings, debug format strings, | |
4733 | names of types. | |
4734 | ||
4735 | An essential and convenient property of all data on @code{obstacks} is | |
4736 | that memory for it gets allocated (with @code{obstack_alloc}) at | |
d3e8051b | 4737 | various times during a debugging session, but it is released all at |
1eb288ea EZ |
4738 | once using the @code{obstack_free} function. The @code{obstack_free} |
4739 | function takes a pointer to where in the stack it must start the | |
4740 | deletion from (much like the cleanup chains have a pointer to where to | |
4741 | start the cleanups). Because of the stack like structure of the | |
4742 | @code{obstacks}, this allows to free only a top portion of the | |
4743 | obstack. There are a few instances in @value{GDBN} where such thing | |
4744 | happens. Calls to @code{obstack_free} are done after some local data | |
4745 | is allocated to the obstack. Only the local data is deleted from the | |
4746 | obstack. Of course this assumes that nothing between the | |
4747 | @code{obstack_alloc} and the @code{obstack_free} allocates anything | |
4748 | else on the same obstack. For this reason it is best and safest to | |
4749 | use temporary @code{obstacks}. | |
4750 | ||
4751 | Releasing the whole obstack is also not safe per se. It is safe only | |
4752 | under the condition that we know the @code{obstacks} memory is no | |
4753 | longer needed. In @value{GDBN} we get rid of the @code{obstacks} only | |
4754 | when we get rid of the whole objfile(s), for instance upon reading a | |
4755 | new symbol file. | |
c906108c SS |
4756 | |
4757 | @section gnu-regex | |
56caf160 | 4758 | @cindex regular expressions library |
c906108c SS |
4759 | |
4760 | Regex conditionals. | |
4761 | ||
4762 | @table @code | |
c906108c SS |
4763 | @item C_ALLOCA |
4764 | ||
4765 | @item NFAILURES | |
4766 | ||
4767 | @item RE_NREGS | |
4768 | ||
4769 | @item SIGN_EXTEND_CHAR | |
4770 | ||
4771 | @item SWITCH_ENUM_BUG | |
4772 | ||
4773 | @item SYNTAX_TABLE | |
4774 | ||
4775 | @item Sword | |
4776 | ||
4777 | @item sparc | |
c906108c SS |
4778 | @end table |
4779 | ||
350da6ee DJ |
4780 | @section Array Containers |
4781 | @cindex Array Containers | |
4782 | @cindex VEC | |
4783 | ||
4784 | Often it is necessary to manipulate a dynamic array of a set of | |
4785 | objects. C forces some bookkeeping on this, which can get cumbersome | |
d3e8051b | 4786 | and repetitive. The @file{vec.h} file contains macros for defining |
350da6ee DJ |
4787 | and using a typesafe vector type. The functions defined will be |
4788 | inlined when compiling, and so the abstraction cost should be zero. | |
4789 | Domain checks are added to detect programming errors. | |
4790 | ||
4791 | An example use would be an array of symbols or section information. | |
4792 | The array can be grown as symbols are read in (or preallocated), and | |
4793 | the accessor macros provided keep care of all the necessary | |
4794 | bookkeeping. Because the arrays are type safe, there is no danger of | |
4795 | accidentally mixing up the contents. Think of these as C++ templates, | |
4796 | but implemented in C. | |
4797 | ||
4798 | Because of the different behavior of structure objects, scalar objects | |
4799 | and of pointers, there are three flavors of vector, one for each of | |
4800 | these variants. Both the structure object and pointer variants pass | |
4801 | pointers to objects around --- in the former case the pointers are | |
4802 | stored into the vector and in the latter case the pointers are | |
4803 | dereferenced and the objects copied into the vector. The scalar | |
4804 | object variant is suitable for @code{int}-like objects, and the vector | |
4805 | elements are returned by value. | |
4806 | ||
4807 | There are both @code{index} and @code{iterate} accessors. The iterator | |
4808 | returns a boolean iteration condition and updates the iteration | |
4809 | variable passed by reference. Because the iterator will be inlined, | |
4810 | the address-of can be optimized away. | |
4811 | ||
4812 | The vectors are implemented using the trailing array idiom, thus they | |
4813 | are not resizeable without changing the address of the vector object | |
4814 | itself. This means you cannot have variables or fields of vector type | |
4815 | --- always use a pointer to a vector. The one exception is the final | |
4816 | field of a structure, which could be a vector type. You will have to | |
4817 | use the @code{embedded_size} & @code{embedded_init} calls to create | |
4818 | such objects, and they will probably not be resizeable (so don't use | |
4819 | the @dfn{safe} allocation variants). The trailing array idiom is used | |
4820 | (rather than a pointer to an array of data), because, if we allow | |
4821 | @code{NULL} to also represent an empty vector, empty vectors occupy | |
4822 | minimal space in the structure containing them. | |
4823 | ||
4824 | Each operation that increases the number of active elements is | |
4825 | available in @dfn{quick} and @dfn{safe} variants. The former presumes | |
4826 | that there is sufficient allocated space for the operation to succeed | |
4827 | (it dies if there is not). The latter will reallocate the vector, if | |
4828 | needed. Reallocation causes an exponential increase in vector size. | |
4829 | If you know you will be adding N elements, it would be more efficient | |
4830 | to use the reserve operation before adding the elements with the | |
4831 | @dfn{quick} operation. This will ensure there are at least as many | |
4832 | elements as you ask for, it will exponentially increase if there are | |
4833 | too few spare slots. If you want reserve a specific number of slots, | |
4834 | but do not want the exponential increase (for instance, you know this | |
4835 | is the last allocation), use a negative number for reservation. You | |
4836 | can also create a vector of a specific size from the get go. | |
4837 | ||
4838 | You should prefer the push and pop operations, as they append and | |
4839 | remove from the end of the vector. If you need to remove several items | |
4840 | in one go, use the truncate operation. The insert and remove | |
4841 | operations allow you to change elements in the middle of the vector. | |
4842 | There are two remove operations, one which preserves the element | |
4843 | ordering @code{ordered_remove}, and one which does not | |
4844 | @code{unordered_remove}. The latter function copies the end element | |
4845 | into the removed slot, rather than invoke a memmove operation. The | |
4846 | @code{lower_bound} function will determine where to place an item in | |
4847 | the array using insert that will maintain sorted order. | |
4848 | ||
4849 | If you need to directly manipulate a vector, then the @code{address} | |
4850 | accessor will return the address of the start of the vector. Also the | |
4851 | @code{space} predicate will tell you whether there is spare capacity in the | |
4852 | vector. You will not normally need to use these two functions. | |
4853 | ||
4854 | Vector types are defined using a | |
4855 | @code{DEF_VEC_@{O,P,I@}(@var{typename})} macro. Variables of vector | |
4856 | type are declared using a @code{VEC(@var{typename})} macro. The | |
4857 | characters @code{O}, @code{P} and @code{I} indicate whether | |
4858 | @var{typename} is an object (@code{O}), pointer (@code{P}) or integral | |
4859 | (@code{I}) type. Be careful to pick the correct one, as you'll get an | |
4860 | awkward and inefficient API if you use the wrong one. There is a | |
4861 | check, which results in a compile-time warning, for the @code{P} and | |
4862 | @code{I} versions, but there is no check for the @code{O} versions, as | |
4863 | that is not possible in plain C. | |
4864 | ||
4865 | An example of their use would be, | |
4866 | ||
4867 | @smallexample | |
4868 | DEF_VEC_P(tree); // non-managed tree vector. | |
4869 | ||
4870 | struct my_struct @{ | |
4871 | VEC(tree) *v; // A (pointer to) a vector of tree pointers. | |
4872 | @}; | |
4873 | ||
4874 | struct my_struct *s; | |
4875 | ||
4876 | if (VEC_length(tree, s->v)) @{ we have some contents @} | |
4877 | VEC_safe_push(tree, s->v, decl); // append some decl onto the end | |
4878 | for (ix = 0; VEC_iterate(tree, s->v, ix, elt); ix++) | |
4879 | @{ do something with elt @} | |
4880 | ||
4881 | @end smallexample | |
4882 | ||
4883 | The @file{vec.h} file provides details on how to invoke the various | |
4884 | accessors provided. They are enumerated here: | |
4885 | ||
4886 | @table @code | |
4887 | @item VEC_length | |
4888 | Return the number of items in the array, | |
4889 | ||
4890 | @item VEC_empty | |
4891 | Return true if the array has no elements. | |
4892 | ||
4893 | @item VEC_last | |
4894 | @itemx VEC_index | |
4895 | Return the last or arbitrary item in the array. | |
4896 | ||
4897 | @item VEC_iterate | |
4898 | Access an array element and indicate whether the array has been | |
4899 | traversed. | |
4900 | ||
4901 | @item VEC_alloc | |
4902 | @itemx VEC_free | |
4903 | Create and destroy an array. | |
4904 | ||
4905 | @item VEC_embedded_size | |
4906 | @itemx VEC_embedded_init | |
4907 | Helpers for embedding an array as the final element of another struct. | |
4908 | ||
4909 | @item VEC_copy | |
4910 | Duplicate an array. | |
4911 | ||
4912 | @item VEC_space | |
4913 | Return the amount of free space in an array. | |
4914 | ||
4915 | @item VEC_reserve | |
4916 | Ensure a certain amount of free space. | |
4917 | ||
4918 | @item VEC_quick_push | |
4919 | @itemx VEC_safe_push | |
4920 | Append to an array, either assuming the space is available, or making | |
4921 | sure that it is. | |
4922 | ||
4923 | @item VEC_pop | |
4924 | Remove the last item from an array. | |
4925 | ||
4926 | @item VEC_truncate | |
4927 | Remove several items from the end of an array. | |
4928 | ||
4929 | @item VEC_safe_grow | |
4930 | Add several items to the end of an array. | |
4931 | ||
4932 | @item VEC_replace | |
4933 | Overwrite an item in the array. | |
4934 | ||
4935 | @item VEC_quick_insert | |
4936 | @itemx VEC_safe_insert | |
4937 | Insert an item into the middle of the array. Either the space must | |
4938 | already exist, or the space is created. | |
4939 | ||
4940 | @item VEC_ordered_remove | |
4941 | @itemx VEC_unordered_remove | |
4942 | Remove an item from the array, preserving order or not. | |
4943 | ||
4944 | @item VEC_block_remove | |
4945 | Remove a set of items from the array. | |
4946 | ||
4947 | @item VEC_address | |
4948 | Provide the address of the first element. | |
4949 | ||
4950 | @item VEC_lower_bound | |
4951 | Binary search the array. | |
4952 | ||
4953 | @end table | |
4954 | ||
c906108c SS |
4955 | @section include |
4956 | ||
4957 | @node Coding | |
4958 | ||
4959 | @chapter Coding | |
4960 | ||
4961 | This chapter covers topics that are lower-level than the major | |
25822942 | 4962 | algorithms of @value{GDBN}. |
c906108c SS |
4963 | |
4964 | @section Cleanups | |
56caf160 | 4965 | @cindex cleanups |
c906108c SS |
4966 | |
4967 | Cleanups are a structured way to deal with things that need to be done | |
cc1cb004 | 4968 | later. |
c906108c | 4969 | |
cc1cb004 AC |
4970 | When your code does something (e.g., @code{xmalloc} some memory, or |
4971 | @code{open} a file) that needs to be undone later (e.g., @code{xfree} | |
4972 | the memory or @code{close} the file), it can make a cleanup. The | |
4973 | cleanup will be done at some future point: when the command is finished | |
4974 | and control returns to the top level; when an error occurs and the stack | |
4975 | is unwound; or when your code decides it's time to explicitly perform | |
4976 | cleanups. Alternatively you can elect to discard the cleanups you | |
4977 | created. | |
c906108c SS |
4978 | |
4979 | Syntax: | |
4980 | ||
4981 | @table @code | |
c906108c SS |
4982 | @item struct cleanup *@var{old_chain}; |
4983 | Declare a variable which will hold a cleanup chain handle. | |
4984 | ||
56caf160 | 4985 | @findex make_cleanup |
c906108c SS |
4986 | @item @var{old_chain} = make_cleanup (@var{function}, @var{arg}); |
4987 | Make a cleanup which will cause @var{function} to be called with | |
4988 | @var{arg} (a @code{char *}) later. The result, @var{old_chain}, is a | |
cc1cb004 AC |
4989 | handle that can later be passed to @code{do_cleanups} or |
4990 | @code{discard_cleanups}. Unless you are going to call | |
4991 | @code{do_cleanups} or @code{discard_cleanups}, you can ignore the result | |
4992 | from @code{make_cleanup}. | |
c906108c | 4993 | |
56caf160 | 4994 | @findex do_cleanups |
c906108c | 4995 | @item do_cleanups (@var{old_chain}); |
cc1cb004 AC |
4996 | Do all cleanups added to the chain since the corresponding |
4997 | @code{make_cleanup} call was made. | |
4998 | ||
4999 | @findex discard_cleanups | |
5000 | @item discard_cleanups (@var{old_chain}); | |
5001 | Same as @code{do_cleanups} except that it just removes the cleanups from | |
5002 | the chain and does not call the specified functions. | |
5003 | @end table | |
5004 | ||
5005 | Cleanups are implemented as a chain. The handle returned by | |
5006 | @code{make_cleanups} includes the cleanup passed to the call and any | |
5007 | later cleanups appended to the chain (but not yet discarded or | |
5008 | performed). E.g.: | |
56caf160 | 5009 | |
474c8240 | 5010 | @smallexample |
c906108c | 5011 | make_cleanup (a, 0); |
cc1cb004 AC |
5012 | @{ |
5013 | struct cleanup *old = make_cleanup (b, 0); | |
5014 | make_cleanup (c, 0) | |
5015 | ... | |
5016 | do_cleanups (old); | |
5017 | @} | |
474c8240 | 5018 | @end smallexample |
56caf160 | 5019 | |
c906108c | 5020 | @noindent |
cc1cb004 AC |
5021 | will call @code{c()} and @code{b()} but will not call @code{a()}. The |
5022 | cleanup that calls @code{a()} will remain in the cleanup chain, and will | |
5023 | be done later unless otherwise discarded.@refill | |
5024 | ||
5025 | Your function should explicitly do or discard the cleanups it creates. | |
5026 | Failing to do this leads to non-deterministic behavior since the caller | |
5027 | will arbitrarily do or discard your functions cleanups. This need leads | |
5028 | to two common cleanup styles. | |
5029 | ||
5030 | The first style is try/finally. Before it exits, your code-block calls | |
5031 | @code{do_cleanups} with the old cleanup chain and thus ensures that your | |
5032 | code-block's cleanups are always performed. For instance, the following | |
5033 | code-segment avoids a memory leak problem (even when @code{error} is | |
5034 | called and a forced stack unwind occurs) by ensuring that the | |
5035 | @code{xfree} will always be called: | |
c906108c | 5036 | |
474c8240 | 5037 | @smallexample |
cc1cb004 AC |
5038 | struct cleanup *old = make_cleanup (null_cleanup, 0); |
5039 | data = xmalloc (sizeof blah); | |
5040 | make_cleanup (xfree, data); | |
5041 | ... blah blah ... | |
5042 | do_cleanups (old); | |
474c8240 | 5043 | @end smallexample |
cc1cb004 AC |
5044 | |
5045 | The second style is try/except. Before it exits, your code-block calls | |
5046 | @code{discard_cleanups} with the old cleanup chain and thus ensures that | |
5047 | any created cleanups are not performed. For instance, the following | |
5048 | code segment, ensures that the file will be closed but only if there is | |
5049 | an error: | |
5050 | ||
474c8240 | 5051 | @smallexample |
cc1cb004 AC |
5052 | FILE *file = fopen ("afile", "r"); |
5053 | struct cleanup *old = make_cleanup (close_file, file); | |
5054 | ... blah blah ... | |
5055 | discard_cleanups (old); | |
5056 | return file; | |
474c8240 | 5057 | @end smallexample |
c906108c | 5058 | |
c1468174 | 5059 | Some functions, e.g., @code{fputs_filtered()} or @code{error()}, specify |
c906108c SS |
5060 | that they ``should not be called when cleanups are not in place''. This |
5061 | means that any actions you need to reverse in the case of an error or | |
5062 | interruption must be on the cleanup chain before you call these | |
5063 | functions, since they might never return to your code (they | |
5064 | @samp{longjmp} instead). | |
5065 | ||
ba8c9337 AC |
5066 | @section Per-architecture module data |
5067 | @cindex per-architecture module data | |
5068 | @cindex multi-arch data | |
5069 | @cindex data-pointer, per-architecture/per-module | |
5070 | ||
fc989b7a AC |
5071 | The multi-arch framework includes a mechanism for adding module |
5072 | specific per-architecture data-pointers to the @code{struct gdbarch} | |
5073 | architecture object. | |
5074 | ||
5075 | A module registers one or more per-architecture data-pointers using: | |
5076 | ||
5077 | @deftypefun struct gdbarch_data *gdbarch_data_register_pre_init (gdbarch_data_pre_init_ftype *@var{pre_init}) | |
5078 | @var{pre_init} is used to, on-demand, allocate an initial value for a | |
5079 | per-architecture data-pointer using the architecture's obstack (passed | |
5080 | in as a parameter). Since @var{pre_init} can be called during | |
5081 | architecture creation, it is not parameterized with the architecture. | |
5082 | and must not call modules that use per-architecture data. | |
5083 | @end deftypefun | |
ba8c9337 | 5084 | |
fc989b7a AC |
5085 | @deftypefun struct gdbarch_data *gdbarch_data_register_post_init (gdbarch_data_post_init_ftype *@var{post_init}) |
5086 | @var{post_init} is used to obtain an initial value for a | |
5087 | per-architecture data-pointer @emph{after}. Since @var{post_init} is | |
5088 | always called after architecture creation, it both receives the fully | |
5089 | initialized architecture and is free to call modules that use | |
5090 | per-architecture data (care needs to be taken to ensure that those | |
5091 | other modules do not try to call back to this module as that will | |
5092 | create in cycles in the initialization call graph). | |
5093 | @end deftypefun | |
ba8c9337 | 5094 | |
fc989b7a AC |
5095 | These functions return a @code{struct gdbarch_data} that is used to |
5096 | identify the per-architecture data-pointer added for that module. | |
ba8c9337 | 5097 | |
fc989b7a | 5098 | The per-architecture data-pointer is accessed using the function: |
ba8c9337 | 5099 | |
fc989b7a AC |
5100 | @deftypefun void *gdbarch_data (struct gdbarch *@var{gdbarch}, struct gdbarch_data *@var{data_handle}) |
5101 | Given the architecture @var{arch} and module data handle | |
5102 | @var{data_handle} (returned by @code{gdbarch_data_register_pre_init} | |
5103 | or @code{gdbarch_data_register_post_init}), this function returns the | |
5104 | current value of the per-architecture data-pointer. If the data | |
5105 | pointer is @code{NULL}, it is first initialized by calling the | |
5106 | corresponding @var{pre_init} or @var{post_init} method. | |
ba8c9337 AC |
5107 | @end deftypefun |
5108 | ||
fc989b7a | 5109 | The examples below assume the following definitions: |
ba8c9337 AC |
5110 | |
5111 | @smallexample | |
e7f16015 | 5112 | struct nozel @{ int total; @}; |
ba8c9337 | 5113 | static struct gdbarch_data *nozel_handle; |
ba8c9337 AC |
5114 | @end smallexample |
5115 | ||
fc989b7a AC |
5116 | A module can extend the architecture vector, adding additional |
5117 | per-architecture data, using the @var{pre_init} method. The module's | |
5118 | per-architecture data is then initialized during architecture | |
5119 | creation. | |
ba8c9337 | 5120 | |
fc989b7a AC |
5121 | In the below, the module's per-architecture @emph{nozel} is added. An |
5122 | architecture can specify its nozel by calling @code{set_gdbarch_nozel} | |
5123 | from @code{gdbarch_init}. | |
ba8c9337 AC |
5124 | |
5125 | @smallexample | |
fc989b7a AC |
5126 | static void * |
5127 | nozel_pre_init (struct obstack *obstack) | |
ba8c9337 | 5128 | @{ |
fc989b7a AC |
5129 | struct nozel *data = OBSTACK_ZALLOC (obstack, struct nozel); |
5130 | return data; | |
5131 | @} | |
ba8c9337 AC |
5132 | @end smallexample |
5133 | ||
ba8c9337 | 5134 | @smallexample |
fc989b7a AC |
5135 | extern void |
5136 | set_gdbarch_nozel (struct gdbarch *gdbarch, int total) | |
ba8c9337 | 5137 | @{ |
ba8c9337 | 5138 | struct nozel *data = gdbarch_data (gdbarch, nozel_handle); |
fc989b7a | 5139 | data->total = nozel; |
ba8c9337 AC |
5140 | @} |
5141 | @end smallexample | |
5142 | ||
fc989b7a AC |
5143 | A module can on-demand create architecture dependant data structures |
5144 | using @code{post_init}. | |
ba8c9337 | 5145 | |
fc989b7a AC |
5146 | In the below, the nozel's total is computed on-demand by |
5147 | @code{nozel_post_init} using information obtained from the | |
5148 | architecture. | |
ba8c9337 AC |
5149 | |
5150 | @smallexample | |
fc989b7a AC |
5151 | static void * |
5152 | nozel_post_init (struct gdbarch *gdbarch) | |
ba8c9337 | 5153 | @{ |
fc989b7a AC |
5154 | struct nozel *data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct nozel); |
5155 | nozel->total = gdbarch@dots{} (gdbarch); | |
5156 | return data; | |
ba8c9337 AC |
5157 | @} |
5158 | @end smallexample | |
5159 | ||
5160 | @smallexample | |
fc989b7a AC |
5161 | extern int |
5162 | nozel_total (struct gdbarch *gdbarch) | |
ba8c9337 | 5163 | @{ |
fc989b7a AC |
5164 | struct nozel *data = gdbarch_data (gdbarch, nozel_handle); |
5165 | return data->total; | |
ba8c9337 AC |
5166 | @} |
5167 | @end smallexample | |
5168 | ||
c906108c | 5169 | @section Wrapping Output Lines |
56caf160 | 5170 | @cindex line wrap in output |
c906108c | 5171 | |
56caf160 | 5172 | @findex wrap_here |
c906108c SS |
5173 | Output that goes through @code{printf_filtered} or @code{fputs_filtered} |
5174 | or @code{fputs_demangled} needs only to have calls to @code{wrap_here} | |
5175 | added in places that would be good breaking points. The utility | |
5176 | routines will take care of actually wrapping if the line width is | |
5177 | exceeded. | |
5178 | ||
5179 | The argument to @code{wrap_here} is an indentation string which is | |
5180 | printed @emph{only} if the line breaks there. This argument is saved | |
5181 | away and used later. It must remain valid until the next call to | |
5182 | @code{wrap_here} or until a newline has been printed through the | |
5183 | @code{*_filtered} functions. Don't pass in a local variable and then | |
5184 | return! | |
5185 | ||
56caf160 | 5186 | It is usually best to call @code{wrap_here} after printing a comma or |
c906108c SS |
5187 | space. If you call it before printing a space, make sure that your |
5188 | indentation properly accounts for the leading space that will print if | |
5189 | the line wraps there. | |
5190 | ||
5191 | Any function or set of functions that produce filtered output must | |
5192 | finish by printing a newline, to flush the wrap buffer, before switching | |
56caf160 | 5193 | to unfiltered (@code{printf}) output. Symbol reading routines that |
c906108c SS |
5194 | print warnings are a good example. |
5195 | ||
25822942 | 5196 | @section @value{GDBN} Coding Standards |
56caf160 | 5197 | @cindex coding standards |
c906108c | 5198 | |
25822942 | 5199 | @value{GDBN} follows the GNU coding standards, as described in |
c906108c | 5200 | @file{etc/standards.texi}. This file is also available for anonymous |
af6c57ea AC |
5201 | FTP from GNU archive sites. @value{GDBN} takes a strict interpretation |
5202 | of the standard; in general, when the GNU standard recommends a practice | |
5203 | but does not require it, @value{GDBN} requires it. | |
c906108c | 5204 | |
56caf160 EZ |
5205 | @value{GDBN} follows an additional set of coding standards specific to |
5206 | @value{GDBN}, as described in the following sections. | |
c906108c | 5207 | |
af6c57ea | 5208 | |
b9aa90c9 | 5209 | @subsection ISO C |
af6c57ea | 5210 | |
b9aa90c9 AC |
5211 | @value{GDBN} assumes an ISO/IEC 9899:1990 (a.k.a.@: ISO C90) compliant |
5212 | compiler. | |
af6c57ea | 5213 | |
b9aa90c9 | 5214 | @value{GDBN} does not assume an ISO C or POSIX compliant C library. |
af6c57ea AC |
5215 | |
5216 | ||
5217 | @subsection Memory Management | |
5218 | ||
5219 | @value{GDBN} does not use the functions @code{malloc}, @code{realloc}, | |
5220 | @code{calloc}, @code{free} and @code{asprintf}. | |
5221 | ||
5222 | @value{GDBN} uses the functions @code{xmalloc}, @code{xrealloc} and | |
5223 | @code{xcalloc} when allocating memory. Unlike @code{malloc} et.al.@: | |
5224 | these functions do not return when the memory pool is empty. Instead, | |
5225 | they unwind the stack using cleanups. These functions return | |
5226 | @code{NULL} when requested to allocate a chunk of memory of size zero. | |
5227 | ||
5228 | @emph{Pragmatics: By using these functions, the need to check every | |
5229 | memory allocation is removed. These functions provide portable | |
5230 | behavior.} | |
5231 | ||
5232 | @value{GDBN} does not use the function @code{free}. | |
5233 | ||
5234 | @value{GDBN} uses the function @code{xfree} to return memory to the | |
5235 | memory pool. Consistent with ISO-C, this function ignores a request to | |
5236 | free a @code{NULL} pointer. | |
5237 | ||
5238 | @emph{Pragmatics: On some systems @code{free} fails when passed a | |
5239 | @code{NULL} pointer.} | |
5240 | ||
5241 | @value{GDBN} can use the non-portable function @code{alloca} for the | |
5242 | allocation of small temporary values (such as strings). | |
5243 | ||
5244 | @emph{Pragmatics: This function is very non-portable. Some systems | |
5245 | restrict the memory being allocated to no more than a few kilobytes.} | |
5246 | ||
5247 | @value{GDBN} uses the string function @code{xstrdup} and the print | |
b435e160 | 5248 | function @code{xstrprintf}. |
af6c57ea AC |
5249 | |
5250 | @emph{Pragmatics: @code{asprintf} and @code{strdup} can fail. Print | |
5251 | functions such as @code{sprintf} are very prone to buffer overflow | |
5252 | errors.} | |
5253 | ||
5254 | ||
5255 | @subsection Compiler Warnings | |
56caf160 | 5256 | @cindex compiler warnings |
af6c57ea | 5257 | |
aa79a185 DJ |
5258 | With few exceptions, developers should avoid the configuration option |
5259 | @samp{--disable-werror} when building @value{GDBN}. The exceptions | |
5260 | are listed in the file @file{gdb/MAINTAINERS}. The default, when | |
5261 | building with @sc{gcc}, is @samp{--enable-werror}. | |
af6c57ea AC |
5262 | |
5263 | This option causes @value{GDBN} (when built using GCC) to be compiled | |
5264 | with a carefully selected list of compiler warning flags. Any warnings | |
aa79a185 | 5265 | from those flags are treated as errors. |
af6c57ea AC |
5266 | |
5267 | The current list of warning flags includes: | |
5268 | ||
5269 | @table @samp | |
aa79a185 DJ |
5270 | @item -Wall |
5271 | Recommended @sc{gcc} warnings. | |
af6c57ea | 5272 | |
aa79a185 | 5273 | @item -Wdeclaration-after-statement |
af6c57ea | 5274 | |
aa79a185 DJ |
5275 | @sc{gcc} 3.x (and later) and @sc{c99} allow declarations mixed with |
5276 | code, but @sc{gcc} 2.x and @sc{c89} do not. | |
af6c57ea | 5277 | |
aa79a185 | 5278 | @item -Wpointer-arith |
af6c57ea | 5279 | |
aa79a185 DJ |
5280 | @item -Wformat-nonliteral |
5281 | Non-literal format strings, with a few exceptions, are bugs - they | |
d3e8051b | 5282 | might contain unintended user-supplied format specifiers. |
af6c57ea | 5283 | Since @value{GDBN} uses the @code{format printf} attribute on all |
aa79a185 | 5284 | @code{printf} like functions this checks not just @code{printf} calls |
af6c57ea AC |
5285 | but also calls to functions such as @code{fprintf_unfiltered}. |
5286 | ||
7be93b9e JB |
5287 | @item -Wno-pointer-sign |
5288 | In version 4.0, GCC began warning about pointer argument passing or | |
5289 | assignment even when the source and destination differed only in | |
5290 | signedness. However, most @value{GDBN} code doesn't distinguish | |
5291 | carefully between @code{char} and @code{unsigned char}. In early 2006 | |
5292 | the @value{GDBN} developers decided correcting these warnings wasn't | |
5293 | worth the time it would take. | |
5294 | ||
aa79a185 DJ |
5295 | @item -Wno-unused-parameter |
5296 | Due to the way that @value{GDBN} is implemented many functions have | |
5297 | unused parameters. Consequently this warning is avoided. The macro | |
af6c57ea AC |
5298 | @code{ATTRIBUTE_UNUSED} is not used as it leads to false negatives --- |
5299 | it is not an error to have @code{ATTRIBUTE_UNUSED} on a parameter that | |
aa79a185 DJ |
5300 | is being used. |
5301 | ||
5302 | @item -Wno-unused | |
5303 | @itemx -Wno-switch | |
58b38ee2 | 5304 | @itemx -Wno-char-subscripts |
aa79a185 DJ |
5305 | These are warnings which might be useful for @value{GDBN}, but are |
5306 | currently too noisy to enable with @samp{-Werror}. | |
af6c57ea | 5307 | |
aa79a185 | 5308 | @end table |
c906108c SS |
5309 | |
5310 | @subsection Formatting | |
5311 | ||
56caf160 | 5312 | @cindex source code formatting |
c906108c SS |
5313 | The standard GNU recommendations for formatting must be followed |
5314 | strictly. | |
5315 | ||
af6c57ea AC |
5316 | A function declaration should not have its name in column zero. A |
5317 | function definition should have its name in column zero. | |
5318 | ||
474c8240 | 5319 | @smallexample |
af6c57ea AC |
5320 | /* Declaration */ |
5321 | static void foo (void); | |
5322 | /* Definition */ | |
5323 | void | |
5324 | foo (void) | |
5325 | @{ | |
5326 | @} | |
474c8240 | 5327 | @end smallexample |
af6c57ea AC |
5328 | |
5329 | @emph{Pragmatics: This simplifies scripting. Function definitions can | |
5330 | be found using @samp{^function-name}.} | |
c906108c | 5331 | |
af6c57ea AC |
5332 | There must be a space between a function or macro name and the opening |
5333 | parenthesis of its argument list (except for macro definitions, as | |
5334 | required by C). There must not be a space after an open paren/bracket | |
5335 | or before a close paren/bracket. | |
c906108c SS |
5336 | |
5337 | While additional whitespace is generally helpful for reading, do not use | |
5338 | more than one blank line to separate blocks, and avoid adding whitespace | |
af6c57ea AC |
5339 | after the end of a program line (as of 1/99, some 600 lines had |
5340 | whitespace after the semicolon). Excess whitespace causes difficulties | |
5341 | for @code{diff} and @code{patch} utilities. | |
5342 | ||
5343 | Pointers are declared using the traditional K&R C style: | |
5344 | ||
474c8240 | 5345 | @smallexample |
af6c57ea | 5346 | void *foo; |
474c8240 | 5347 | @end smallexample |
af6c57ea AC |
5348 | |
5349 | @noindent | |
5350 | and not: | |
5351 | ||
474c8240 | 5352 | @smallexample |
af6c57ea AC |
5353 | void * foo; |
5354 | void* foo; | |
474c8240 | 5355 | @end smallexample |
c906108c SS |
5356 | |
5357 | @subsection Comments | |
5358 | ||
56caf160 | 5359 | @cindex comment formatting |
c906108c SS |
5360 | The standard GNU requirements on comments must be followed strictly. |
5361 | ||
af6c57ea AC |
5362 | Block comments must appear in the following form, with no @code{/*}- or |
5363 | @code{*/}-only lines, and no leading @code{*}: | |
c906108c | 5364 | |
474c8240 | 5365 | @smallexample |
c906108c SS |
5366 | /* Wait for control to return from inferior to debugger. If inferior |
5367 | gets a signal, we may decide to start it up again instead of | |
5368 | returning. That is why there is a loop in this function. When | |
5369 | this function actually returns it means the inferior should be left | |
25822942 | 5370 | stopped and @value{GDBN} should read more commands. */ |
474c8240 | 5371 | @end smallexample |
c906108c SS |
5372 | |
5373 | (Note that this format is encouraged by Emacs; tabbing for a multi-line | |
56caf160 | 5374 | comment works correctly, and @kbd{M-q} fills the block consistently.) |
c906108c SS |
5375 | |
5376 | Put a blank line between the block comments preceding function or | |
5377 | variable definitions, and the definition itself. | |
5378 | ||
5379 | In general, put function-body comments on lines by themselves, rather | |
5380 | than trying to fit them into the 20 characters left at the end of a | |
5381 | line, since either the comment or the code will inevitably get longer | |
5382 | than will fit, and then somebody will have to move it anyhow. | |
5383 | ||
5384 | @subsection C Usage | |
5385 | ||
56caf160 | 5386 | @cindex C data types |
c906108c SS |
5387 | Code must not depend on the sizes of C data types, the format of the |
5388 | host's floating point numbers, the alignment of anything, or the order | |
5389 | of evaluation of expressions. | |
5390 | ||
56caf160 | 5391 | @cindex function usage |
c906108c | 5392 | Use functions freely. There are only a handful of compute-bound areas |
56caf160 EZ |
5393 | in @value{GDBN} that might be affected by the overhead of a function |
5394 | call, mainly in symbol reading. Most of @value{GDBN}'s performance is | |
5395 | limited by the target interface (whether serial line or system call). | |
c906108c SS |
5396 | |
5397 | However, use functions with moderation. A thousand one-line functions | |
5398 | are just as hard to understand as a single thousand-line function. | |
5399 | ||
af6c57ea | 5400 | @emph{Macros are bad, M'kay.} |
9e678452 CF |
5401 | (But if you have to use a macro, make sure that the macro arguments are |
5402 | protected with parentheses.) | |
af6c57ea AC |
5403 | |
5404 | @cindex types | |
c906108c | 5405 | |
af6c57ea AC |
5406 | Declarations like @samp{struct foo *} should be used in preference to |
5407 | declarations like @samp{typedef struct foo @{ @dots{} @} *foo_ptr}. | |
5408 | ||
5409 | ||
5410 | @subsection Function Prototypes | |
56caf160 | 5411 | @cindex function prototypes |
af6c57ea AC |
5412 | |
5413 | Prototypes must be used when both @emph{declaring} and @emph{defining} | |
5414 | a function. Prototypes for @value{GDBN} functions must include both the | |
5415 | argument type and name, with the name matching that used in the actual | |
5416 | function definition. | |
c906108c | 5417 | |
53a5351d JM |
5418 | All external functions should have a declaration in a header file that |
5419 | callers include, except for @code{_initialize_*} functions, which must | |
5420 | be external so that @file{init.c} construction works, but shouldn't be | |
5421 | visible to random source files. | |
c906108c | 5422 | |
af6c57ea AC |
5423 | Where a source file needs a forward declaration of a static function, |
5424 | that declaration must appear in a block near the top of the source file. | |
5425 | ||
5426 | ||
5427 | @subsection Internal Error Recovery | |
5428 | ||
5429 | During its execution, @value{GDBN} can encounter two types of errors. | |
5430 | User errors and internal errors. User errors include not only a user | |
5431 | entering an incorrect command but also problems arising from corrupt | |
5432 | object files and system errors when interacting with the target. | |
937f164b FF |
5433 | Internal errors include situations where @value{GDBN} has detected, at |
5434 | run time, a corrupt or erroneous situation. | |
af6c57ea AC |
5435 | |
5436 | When reporting an internal error, @value{GDBN} uses | |
5437 | @code{internal_error} and @code{gdb_assert}. | |
5438 | ||
5439 | @value{GDBN} must not call @code{abort} or @code{assert}. | |
5440 | ||
5441 | @emph{Pragmatics: There is no @code{internal_warning} function. Either | |
5442 | the code detected a user error, recovered from it and issued a | |
5443 | @code{warning} or the code failed to correctly recover from the user | |
5444 | error and issued an @code{internal_error}.} | |
5445 | ||
5446 | @subsection File Names | |
5447 | ||
5448 | Any file used when building the core of @value{GDBN} must be in lower | |
5449 | case. Any file used when building the core of @value{GDBN} must be 8.3 | |
5450 | unique. These requirements apply to both source and generated files. | |
5451 | ||
5452 | @emph{Pragmatics: The core of @value{GDBN} must be buildable on many | |
5453 | platforms including DJGPP and MacOS/HFS. Every time an unfriendly file | |
5454 | is introduced to the build process both @file{Makefile.in} and | |
5455 | @file{configure.in} need to be modified accordingly. Compare the | |
5456 | convoluted conversion process needed to transform @file{COPYING} into | |
5457 | @file{copying.c} with the conversion needed to transform | |
5458 | @file{version.in} into @file{version.c}.} | |
5459 | ||
5460 | Any file non 8.3 compliant file (that is not used when building the core | |
5461 | of @value{GDBN}) must be added to @file{gdb/config/djgpp/fnchange.lst}. | |
5462 | ||
5463 | @emph{Pragmatics: This is clearly a compromise.} | |
5464 | ||
5465 | When @value{GDBN} has a local version of a system header file (ex | |
5466 | @file{string.h}) the file name based on the POSIX header prefixed with | |
b4177fca DJ |
5467 | @file{gdb_} (@file{gdb_string.h}). These headers should be relatively |
5468 | independent: they should use only macros defined by @file{configure}, | |
5469 | the compiler, or the host; they should include only system headers; they | |
5470 | should refer only to system types. They may be shared between multiple | |
5471 | programs, e.g.@: @value{GDBN} and @sc{gdbserver}. | |
af6c57ea AC |
5472 | |
5473 | For other files @samp{-} is used as the separator. | |
5474 | ||
5475 | ||
5476 | @subsection Include Files | |
5477 | ||
e2b28d04 | 5478 | A @file{.c} file should include @file{defs.h} first. |
af6c57ea | 5479 | |
e2b28d04 AC |
5480 | A @file{.c} file should directly include the @code{.h} file of every |
5481 | declaration and/or definition it directly refers to. It cannot rely on | |
5482 | indirect inclusion. | |
af6c57ea | 5483 | |
e2b28d04 AC |
5484 | A @file{.h} file should directly include the @code{.h} file of every |
5485 | declaration and/or definition it directly refers to. It cannot rely on | |
5486 | indirect inclusion. Exception: The file @file{defs.h} does not need to | |
5487 | be directly included. | |
af6c57ea | 5488 | |
e2b28d04 | 5489 | An external declaration should only appear in one include file. |
af6c57ea | 5490 | |
e2b28d04 AC |
5491 | An external declaration should never appear in a @code{.c} file. |
5492 | Exception: a declaration for the @code{_initialize} function that | |
5493 | pacifies @option{-Wmissing-declaration}. | |
5494 | ||
5495 | A @code{typedef} definition should only appear in one include file. | |
5496 | ||
5497 | An opaque @code{struct} declaration can appear in multiple @file{.h} | |
5498 | files. Where possible, a @file{.h} file should use an opaque | |
5499 | @code{struct} declaration instead of an include. | |
5500 | ||
5501 | All @file{.h} files should be wrapped in: | |
af6c57ea | 5502 | |
474c8240 | 5503 | @smallexample |
af6c57ea AC |
5504 | #ifndef INCLUDE_FILE_NAME_H |
5505 | #define INCLUDE_FILE_NAME_H | |
5506 | header body | |
5507 | #endif | |
474c8240 | 5508 | @end smallexample |
af6c57ea | 5509 | |
c906108c | 5510 | |
dab11f21 | 5511 | @subsection Clean Design and Portable Implementation |
c906108c | 5512 | |
56caf160 | 5513 | @cindex design |
c906108c | 5514 | In addition to getting the syntax right, there's the little question of |
25822942 | 5515 | semantics. Some things are done in certain ways in @value{GDBN} because long |
c906108c SS |
5516 | experience has shown that the more obvious ways caused various kinds of |
5517 | trouble. | |
5518 | ||
56caf160 | 5519 | @cindex assumptions about targets |
c906108c SS |
5520 | You can't assume the byte order of anything that comes from a target |
5521 | (including @var{value}s, object files, and instructions). Such things | |
56caf160 EZ |
5522 | must be byte-swapped using @code{SWAP_TARGET_AND_HOST} in |
5523 | @value{GDBN}, or one of the swap routines defined in @file{bfd.h}, | |
5524 | such as @code{bfd_get_32}. | |
c906108c SS |
5525 | |
5526 | You can't assume that you know what interface is being used to talk to | |
5527 | the target system. All references to the target must go through the | |
5528 | current @code{target_ops} vector. | |
5529 | ||
5530 | You can't assume that the host and target machines are the same machine | |
5531 | (except in the ``native'' support modules). In particular, you can't | |
5532 | assume that the target machine's header files will be available on the | |
5533 | host machine. Target code must bring along its own header files -- | |
5534 | written from scratch or explicitly donated by their owner, to avoid | |
5535 | copyright problems. | |
5536 | ||
56caf160 | 5537 | @cindex portability |
c906108c SS |
5538 | Insertion of new @code{#ifdef}'s will be frowned upon. It's much better |
5539 | to write the code portably than to conditionalize it for various | |
5540 | systems. | |
5541 | ||
56caf160 | 5542 | @cindex system dependencies |
c906108c SS |
5543 | New @code{#ifdef}'s which test for specific compilers or manufacturers |
5544 | or operating systems are unacceptable. All @code{#ifdef}'s should test | |
5545 | for features. The information about which configurations contain which | |
5546 | features should be segregated into the configuration files. Experience | |
5547 | has proven far too often that a feature unique to one particular system | |
5548 | often creeps into other systems; and that a conditional based on some | |
5549 | predefined macro for your current system will become worthless over | |
5550 | time, as new versions of your system come out that behave differently | |
5551 | with regard to this feature. | |
5552 | ||
5553 | Adding code that handles specific architectures, operating systems, | |
af6c57ea | 5554 | target interfaces, or hosts, is not acceptable in generic code. |
c906108c | 5555 | |
dab11f21 EZ |
5556 | @cindex portable file name handling |
5557 | @cindex file names, portability | |
5558 | One particularly notorious area where system dependencies tend to | |
5559 | creep in is handling of file names. The mainline @value{GDBN} code | |
5560 | assumes Posix semantics of file names: absolute file names begin with | |
5561 | a forward slash @file{/}, slashes are used to separate leading | |
5562 | directories, case-sensitive file names. These assumptions are not | |
5563 | necessarily true on non-Posix systems such as MS-Windows. To avoid | |
5564 | system-dependent code where you need to take apart or construct a file | |
5565 | name, use the following portable macros: | |
5566 | ||
5567 | @table @code | |
5568 | @findex HAVE_DOS_BASED_FILE_SYSTEM | |
5569 | @item HAVE_DOS_BASED_FILE_SYSTEM | |
5570 | This preprocessing symbol is defined to a non-zero value on hosts | |
5571 | whose filesystems belong to the MS-DOS/MS-Windows family. Use this | |
5572 | symbol to write conditional code which should only be compiled for | |
5573 | such hosts. | |
5574 | ||
5575 | @findex IS_DIR_SEPARATOR | |
4be31470 | 5576 | @item IS_DIR_SEPARATOR (@var{c}) |
dab11f21 EZ |
5577 | Evaluates to a non-zero value if @var{c} is a directory separator |
5578 | character. On Unix and GNU/Linux systems, only a slash @file{/} is | |
5579 | such a character, but on Windows, both @file{/} and @file{\} will | |
5580 | pass. | |
5581 | ||
5582 | @findex IS_ABSOLUTE_PATH | |
5583 | @item IS_ABSOLUTE_PATH (@var{file}) | |
5584 | Evaluates to a non-zero value if @var{file} is an absolute file name. | |
5585 | For Unix and GNU/Linux hosts, a name which begins with a slash | |
5586 | @file{/} is absolute. On DOS and Windows, @file{d:/foo} and | |
5587 | @file{x:\bar} are also absolute file names. | |
5588 | ||
5589 | @findex FILENAME_CMP | |
5590 | @item FILENAME_CMP (@var{f1}, @var{f2}) | |
5591 | Calls a function which compares file names @var{f1} and @var{f2} as | |
5592 | appropriate for the underlying host filesystem. For Posix systems, | |
5593 | this simply calls @code{strcmp}; on case-insensitive filesystems it | |
5594 | will call @code{strcasecmp} instead. | |
5595 | ||
5596 | @findex DIRNAME_SEPARATOR | |
5597 | @item DIRNAME_SEPARATOR | |
5598 | Evaluates to a character which separates directories in | |
5599 | @code{PATH}-style lists, typically held in environment variables. | |
5600 | This character is @samp{:} on Unix, @samp{;} on DOS and Windows. | |
5601 | ||
5602 | @findex SLASH_STRING | |
5603 | @item SLASH_STRING | |
5604 | This evaluates to a constant string you should use to produce an | |
5605 | absolute filename from leading directories and the file's basename. | |
5606 | @code{SLASH_STRING} is @code{"/"} on most systems, but might be | |
5607 | @code{"\\"} for some Windows-based ports. | |
5608 | @end table | |
5609 | ||
5610 | In addition to using these macros, be sure to use portable library | |
5611 | functions whenever possible. For example, to extract a directory or a | |
5612 | basename part from a file name, use the @code{dirname} and | |
5613 | @code{basename} library functions (available in @code{libiberty} for | |
5614 | platforms which don't provide them), instead of searching for a slash | |
5615 | with @code{strrchr}. | |
5616 | ||
25822942 DB |
5617 | Another way to generalize @value{GDBN} along a particular interface is with an |
5618 | attribute struct. For example, @value{GDBN} has been generalized to handle | |
56caf160 EZ |
5619 | multiple kinds of remote interfaces---not by @code{#ifdef}s everywhere, but |
5620 | by defining the @code{target_ops} structure and having a current target (as | |
c906108c SS |
5621 | well as a stack of targets below it, for memory references). Whenever |
5622 | something needs to be done that depends on which remote interface we are | |
56caf160 EZ |
5623 | using, a flag in the current target_ops structure is tested (e.g., |
5624 | @code{target_has_stack}), or a function is called through a pointer in the | |
c906108c | 5625 | current target_ops structure. In this way, when a new remote interface |
56caf160 | 5626 | is added, only one module needs to be touched---the one that actually |
c906108c SS |
5627 | implements the new remote interface. Other examples of |
5628 | attribute-structs are BFD access to multiple kinds of object file | |
25822942 | 5629 | formats, or @value{GDBN}'s access to multiple source languages. |
c906108c | 5630 | |
56caf160 EZ |
5631 | Please avoid duplicating code. For example, in @value{GDBN} 3.x all |
5632 | the code interfacing between @code{ptrace} and the rest of | |
5633 | @value{GDBN} was duplicated in @file{*-dep.c}, and so changing | |
5634 | something was very painful. In @value{GDBN} 4.x, these have all been | |
5635 | consolidated into @file{infptrace.c}. @file{infptrace.c} can deal | |
5636 | with variations between systems the same way any system-independent | |
5637 | file would (hooks, @code{#if defined}, etc.), and machines which are | |
5638 | radically different don't need to use @file{infptrace.c} at all. | |
c906108c | 5639 | |
af6c57ea AC |
5640 | All debugging code must be controllable using the @samp{set debug |
5641 | @var{module}} command. Do not use @code{printf} to print trace | |
5642 | messages. Use @code{fprintf_unfiltered(gdb_stdlog, ...}. Do not use | |
5643 | @code{#ifdef DEBUG}. | |
5644 | ||
c906108c | 5645 | |
8487521e | 5646 | @node Porting GDB |
c906108c | 5647 | |
25822942 | 5648 | @chapter Porting @value{GDBN} |
56caf160 | 5649 | @cindex porting to new machines |
c906108c | 5650 | |
56caf160 EZ |
5651 | Most of the work in making @value{GDBN} compile on a new machine is in |
5652 | specifying the configuration of the machine. This is done in a | |
5653 | dizzying variety of header files and configuration scripts, which we | |
5654 | hope to make more sensible soon. Let's say your new host is called an | |
5655 | @var{xyz} (e.g., @samp{sun4}), and its full three-part configuration | |
5656 | name is @code{@var{arch}-@var{xvend}-@var{xos}} (e.g., | |
5657 | @samp{sparc-sun-sunos4}). In particular: | |
c906108c | 5658 | |
56caf160 EZ |
5659 | @itemize @bullet |
5660 | @item | |
c906108c SS |
5661 | In the top level directory, edit @file{config.sub} and add @var{arch}, |
5662 | @var{xvend}, and @var{xos} to the lists of supported architectures, | |
5663 | vendors, and operating systems near the bottom of the file. Also, add | |
5664 | @var{xyz} as an alias that maps to | |
5665 | @code{@var{arch}-@var{xvend}-@var{xos}}. You can test your changes by | |
5666 | running | |
5667 | ||
474c8240 | 5668 | @smallexample |
c906108c | 5669 | ./config.sub @var{xyz} |
474c8240 | 5670 | @end smallexample |
56caf160 | 5671 | |
c906108c SS |
5672 | @noindent |
5673 | and | |
56caf160 | 5674 | |
474c8240 | 5675 | @smallexample |
c906108c | 5676 | ./config.sub @code{@var{arch}-@var{xvend}-@var{xos}} |
474c8240 | 5677 | @end smallexample |
56caf160 | 5678 | |
c906108c SS |
5679 | @noindent |
5680 | which should both respond with @code{@var{arch}-@var{xvend}-@var{xos}} | |
5681 | and no error messages. | |
5682 | ||
56caf160 | 5683 | @noindent |
c906108c SS |
5684 | You need to port BFD, if that hasn't been done already. Porting BFD is |
5685 | beyond the scope of this manual. | |
5686 | ||
56caf160 | 5687 | @item |
25822942 | 5688 | To configure @value{GDBN} itself, edit @file{gdb/configure.host} to recognize |
c906108c SS |
5689 | your system and set @code{gdb_host} to @var{xyz}, and (unless your |
5690 | desired target is already available) also edit @file{gdb/configure.tgt}, | |
5691 | setting @code{gdb_target} to something appropriate (for instance, | |
5692 | @var{xyz}). | |
5693 | ||
7fd60527 AC |
5694 | @emph{Maintainer's note: Work in progress. The file |
5695 | @file{gdb/configure.host} originally needed to be modified when either a | |
5696 | new native target or a new host machine was being added to @value{GDBN}. | |
5697 | Recent changes have removed this requirement. The file now only needs | |
5698 | to be modified when adding a new native configuration. This will likely | |
5699 | changed again in the future.} | |
5700 | ||
56caf160 | 5701 | @item |
25822942 | 5702 | Finally, you'll need to specify and define @value{GDBN}'s host-, native-, and |
c906108c SS |
5703 | target-dependent @file{.h} and @file{.c} files used for your |
5704 | configuration. | |
56caf160 | 5705 | @end itemize |
c906108c | 5706 | |
d52fe014 AC |
5707 | @node Versions and Branches |
5708 | @chapter Versions and Branches | |
8973da3a | 5709 | |
d52fe014 | 5710 | @section Versions |
8973da3a | 5711 | |
d52fe014 AC |
5712 | @value{GDBN}'s version is determined by the file |
5713 | @file{gdb/version.in} and takes one of the following forms: | |
fb0ff88f | 5714 | |
d52fe014 AC |
5715 | @table @asis |
5716 | @item @var{major}.@var{minor} | |
5717 | @itemx @var{major}.@var{minor}.@var{patchlevel} | |
53531fc1 AC |
5718 | an official release (e.g., 6.2 or 6.2.1) |
5719 | @item @var{major}.@var{minor}.@var{patchlevel}.@var{YYYY}@var{MM}@var{DD} | |
5720 | a snapshot taken at @var{YYYY}-@var{MM}-@var{DD}-gmt (e.g., | |
5721 | 6.1.50.20020302, 6.1.90.20020304, or 6.1.0.20020308) | |
5722 | @item @var{major}.@var{minor}.@var{patchlevel}.@var{YYYY}@var{MM}@var{DD}-cvs | |
5723 | a @sc{cvs} check out drawn on @var{YYYY}-@var{MM}-@var{DD} (e.g., | |
5724 | 6.1.50.20020302-cvs, 6.1.90.20020304-cvs, or 6.1.0.20020308-cvs) | |
5725 | @item @var{major}.@var{minor}.@var{patchlevel}.@var{YYYY}@var{MM}@var{DD} (@var{vendor}) | |
d52fe014 | 5726 | a vendor specific release of @value{GDBN}, that while based on@* |
53531fc1 AC |
5727 | @var{major}.@var{minor}.@var{patchlevel}.@var{YYYY}@var{MM}@var{DD}, |
5728 | may include additional changes | |
d52fe014 | 5729 | @end table |
fb0ff88f | 5730 | |
d52fe014 AC |
5731 | @value{GDBN}'s mainline uses the @var{major} and @var{minor} version |
5732 | numbers from the most recent release branch, with a @var{patchlevel} | |
53531fc1 AC |
5733 | of 50. At the time each new release branch is created, the mainline's |
5734 | @var{major} and @var{minor} version numbers are updated. | |
fb0ff88f | 5735 | |
53531fc1 AC |
5736 | @value{GDBN}'s release branch is similar. When the branch is cut, the |
5737 | @var{patchlevel} is changed from 50 to 90. As draft releases are | |
5738 | drawn from the branch, the @var{patchlevel} is incremented. Once the | |
5739 | first release (@var{major}.@var{minor}) has been made, the | |
5740 | @var{patchlevel} is set to 0 and updates have an incremented | |
5741 | @var{patchlevel}. | |
5742 | ||
5743 | For snapshots, and @sc{cvs} check outs, it is also possible to | |
5744 | identify the @sc{cvs} origin: | |
5745 | ||
5746 | @table @asis | |
5747 | @item @var{major}.@var{minor}.50.@var{YYYY}@var{MM}@var{DD} | |
5748 | drawn from the @sc{head} of mainline @sc{cvs} (e.g., 6.1.50.20020302) | |
5749 | @item @var{major}.@var{minor}.90.@var{YYYY}@var{MM}@var{DD} | |
5750 | @itemx @var{major}.@var{minor}.91.@var{YYYY}@var{MM}@var{DD} @dots{} | |
5751 | drawn from a release branch prior to the release (e.g., | |
5752 | 6.1.90.20020304) | |
5753 | @item @var{major}.@var{minor}.0.@var{YYYY}@var{MM}@var{DD} | |
5754 | @itemx @var{major}.@var{minor}.1.@var{YYYY}@var{MM}@var{DD} @dots{} | |
5755 | drawn from a release branch after the release (e.g., 6.2.0.20020308) | |
5756 | @end table | |
fb0ff88f | 5757 | |
d52fe014 AC |
5758 | If the previous @value{GDBN} version is 6.1 and the current version is |
5759 | 6.2, then, substituting 6 for @var{major} and 1 or 2 for @var{minor}, | |
5760 | here's an illustration of a typical sequence: | |
fb0ff88f | 5761 | |
d52fe014 AC |
5762 | @smallexample |
5763 | <HEAD> | |
5764 | | | |
53531fc1 | 5765 | 6.1.50.20020302-cvs |
d52fe014 | 5766 | | |
53531fc1 | 5767 | +--------------------------. |
d52fe014 | 5768 | | <gdb_6_2-branch> |
d52fe014 | 5769 | | | |
53531fc1 AC |
5770 | 6.2.50.20020303-cvs 6.1.90 (draft #1) |
5771 | | | | |
5772 | 6.2.50.20020304-cvs 6.1.90.20020304-cvs | |
5773 | | | | |
5774 | 6.2.50.20020305-cvs 6.1.91 (draft #2) | |
d52fe014 | 5775 | | | |
53531fc1 AC |
5776 | 6.2.50.20020306-cvs 6.1.91.20020306-cvs |
5777 | | | | |
5778 | 6.2.50.20020307-cvs 6.2 (release) | |
5779 | | | | |
5780 | 6.2.50.20020308-cvs 6.2.0.20020308-cvs | |
5781 | | | | |
5782 | 6.2.50.20020309-cvs 6.2.1 (update) | |
5783 | | | | |
5784 | 6.2.50.20020310-cvs <branch closed> | |
d52fe014 | 5785 | | |
53531fc1 | 5786 | 6.2.50.20020311-cvs |
d52fe014 | 5787 | | |
53531fc1 | 5788 | +--------------------------. |
d52fe014 | 5789 | | <gdb_6_3-branch> |
53531fc1 AC |
5790 | | | |
5791 | 6.3.50.20020312-cvs 6.2.90 (draft #1) | |
5792 | | | | |
d52fe014 | 5793 | @end smallexample |
fb0ff88f | 5794 | |
d52fe014 AC |
5795 | @section Release Branches |
5796 | @cindex Release Branches | |
fb0ff88f | 5797 | |
d52fe014 AC |
5798 | @value{GDBN} draws a release series (6.2, 6.2.1, @dots{}) from a |
5799 | single release branch, and identifies that branch using the @sc{cvs} | |
5800 | branch tags: | |
fb0ff88f | 5801 | |
d52fe014 AC |
5802 | @smallexample |
5803 | gdb_@var{major}_@var{minor}-@var{YYYY}@var{MM}@var{DD}-branchpoint | |
5804 | gdb_@var{major}_@var{minor}-branch | |
5805 | gdb_@var{major}_@var{minor}-@var{YYYY}@var{MM}@var{DD}-release | |
5806 | @end smallexample | |
5807 | ||
5808 | @emph{Pragmatics: To help identify the date at which a branch or | |
5809 | release is made, both the branchpoint and release tags include the | |
5810 | date that they are cut (@var{YYYY}@var{MM}@var{DD}) in the tag. The | |
5811 | branch tag, denoting the head of the branch, does not need this.} | |
5812 | ||
5813 | @section Vendor Branches | |
5814 | @cindex vendor branches | |
fb0ff88f AC |
5815 | |
5816 | To avoid version conflicts, vendors are expected to modify the file | |
5817 | @file{gdb/version.in} to include a vendor unique alphabetic identifier | |
5818 | (an official @value{GDBN} release never uses alphabetic characters in | |
d3e8051b | 5819 | its version identifier). E.g., @samp{6.2widgit2}, or @samp{6.2 (Widgit |
d52fe014 AC |
5820 | Inc Patch 2)}. |
5821 | ||
5822 | @section Experimental Branches | |
5823 | @cindex experimental branches | |
5824 | ||
5825 | @subsection Guidelines | |
5826 | ||
5827 | @value{GDBN} permits the creation of branches, cut from the @sc{cvs} | |
5828 | repository, for experimental development. Branches make it possible | |
5829 | for developers to share preliminary work, and maintainers to examine | |
5830 | significant new developments. | |
fb0ff88f | 5831 | |
d52fe014 | 5832 | The following are a set of guidelines for creating such branches: |
fb0ff88f | 5833 | |
d52fe014 AC |
5834 | @table @emph |
5835 | ||
5836 | @item a branch has an owner | |
5837 | The owner can set further policy for a branch, but may not change the | |
5838 | ground rules. In particular, they can set a policy for commits (be it | |
5839 | adding more reviewers or deciding who can commit). | |
5840 | ||
5841 | @item all commits are posted | |
5842 | All changes committed to a branch shall also be posted to | |
5843 | @email{gdb-patches@@sources.redhat.com, the @value{GDBN} patches | |
5844 | mailing list}. While commentary on such changes are encouraged, people | |
5845 | should remember that the changes only apply to a branch. | |
5846 | ||
5847 | @item all commits are covered by an assignment | |
5848 | This ensures that all changes belong to the Free Software Foundation, | |
5849 | and avoids the possibility that the branch may become contaminated. | |
5850 | ||
5851 | @item a branch is focused | |
5852 | A focused branch has a single objective or goal, and does not contain | |
5853 | unnecessary or irrelevant changes. Cleanups, where identified, being | |
5854 | be pushed into the mainline as soon as possible. | |
5855 | ||
5856 | @item a branch tracks mainline | |
5857 | This keeps the level of divergence under control. It also keeps the | |
5858 | pressure on developers to push cleanups and other stuff into the | |
5859 | mainline. | |
5860 | ||
5861 | @item a branch shall contain the entire @value{GDBN} module | |
5862 | The @value{GDBN} module @code{gdb} should be specified when creating a | |
5863 | branch (branches of individual files should be avoided). @xref{Tags}. | |
5864 | ||
5865 | @item a branch shall be branded using @file{version.in} | |
5866 | The file @file{gdb/version.in} shall be modified so that it identifies | |
5867 | the branch @var{owner} and branch @var{name}, e.g., | |
53531fc1 | 5868 | @samp{6.2.50.20030303_owner_name} or @samp{6.2 (Owner Name)}. |
d52fe014 AC |
5869 | |
5870 | @end table | |
fb0ff88f | 5871 | |
d52fe014 AC |
5872 | @subsection Tags |
5873 | @anchor{Tags} | |
fb0ff88f | 5874 | |
d52fe014 AC |
5875 | To simplify the identification of @value{GDBN} branches, the following |
5876 | branch tagging convention is strongly recommended: | |
fb0ff88f | 5877 | |
d52fe014 | 5878 | @table @code |
fb0ff88f | 5879 | |
d52fe014 AC |
5880 | @item @var{owner}_@var{name}-@var{YYYYMMDD}-branchpoint |
5881 | @itemx @var{owner}_@var{name}-@var{YYYYMMDD}-branch | |
5882 | The branch point and corresponding branch tag. @var{YYYYMMDD} is the | |
5883 | date that the branch was created. A branch is created using the | |
5884 | sequence: @anchor{experimental branch tags} | |
474c8240 | 5885 | @smallexample |
d52fe014 AC |
5886 | cvs rtag @var{owner}_@var{name}-@var{YYYYMMDD}-branchpoint gdb |
5887 | cvs rtag -b -r @var{owner}_@var{name}-@var{YYYYMMDD}-branchpoint \ | |
5888 | @var{owner}_@var{name}-@var{YYYYMMDD}-branch gdb | |
474c8240 | 5889 | @end smallexample |
fb0ff88f | 5890 | |
d52fe014 AC |
5891 | @item @var{owner}_@var{name}-@var{yyyymmdd}-mergepoint |
5892 | The tagged point, on the mainline, that was used when merging the branch | |
5893 | on @var{yyyymmdd}. To merge in all changes since the branch was cut, | |
5894 | use a command sequence like: | |
474c8240 | 5895 | @smallexample |
d52fe014 AC |
5896 | cvs rtag @var{owner}_@var{name}-@var{yyyymmdd}-mergepoint gdb |
5897 | cvs update \ | |
5898 | -j@var{owner}_@var{name}-@var{YYYYMMDD}-branchpoint | |
5899 | -j@var{owner}_@var{name}-@var{yyyymmdd}-mergepoint | |
474c8240 | 5900 | @end smallexample |
d52fe014 AC |
5901 | @noindent |
5902 | Similar sequences can be used to just merge in changes since the last | |
5903 | merge. | |
5904 | ||
5905 | @end table | |
fb0ff88f | 5906 | |
d52fe014 AC |
5907 | @noindent |
5908 | For further information on @sc{cvs}, see | |
5909 | @uref{http://www.gnu.org/software/cvs/, Concurrent Versions System}. | |
5910 | ||
55f6ca0f JB |
5911 | @node Start of New Year Procedure |
5912 | @chapter Start of New Year Procedure | |
5913 | @cindex new year procedure | |
5914 | ||
5915 | At the start of each new year, the following actions should be performed: | |
5916 | ||
5917 | @itemize @bullet | |
5918 | @item | |
5919 | Rotate the ChangeLog file | |
5920 | ||
5921 | The current @file{ChangeLog} file should be renamed into | |
5922 | @file{ChangeLog-YYYY} where YYYY is the year that has just passed. | |
5923 | A new @file{ChangeLog} file should be created, and its contents should | |
5924 | contain a reference to the previous ChangeLog. The following should | |
5925 | also be preserved at the end of the new ChangeLog, in order to provide | |
5926 | the appropriate settings when editing this file with Emacs: | |
5927 | @smallexample | |
5928 | Local Variables: | |
5929 | mode: change-log | |
5930 | left-margin: 8 | |
5931 | fill-column: 74 | |
5932 | version-control: never | |
9cb011d3 | 5933 | coding: utf-8 |
55f6ca0f JB |
5934 | End: |
5935 | @end smallexample | |
5936 | ||
7f893741 JB |
5937 | @item |
5938 | Add an entry for the newly created ChangeLog file (@file{ChangeLog-YYYY}) | |
5939 | in @file{gdb/config/djgpp/fnchange.lst}. | |
5940 | ||
55f6ca0f JB |
5941 | @item |
5942 | Update the copyright year in the startup message | |
5943 | ||
9cb011d3 JB |
5944 | Update the copyright year in: |
5945 | @itemize @bullet | |
5946 | @item file @file{top.c}, function @code{print_gdb_version} | |
5947 | @item file @file{gdbserver/server.c}, function @code{gdbserver_version} | |
5948 | @item file @file{gdbserver/gdbreplay.c}, function @code{gdbreplay_version} | |
5949 | @end itemize | |
6ec2edbe JB |
5950 | |
5951 | @item | |
5952 | Add the new year in the copyright notices of all source and documentation | |
5953 | files. This can be done semi-automatically by running the @code{copyright.sh} | |
5954 | script. This script requires Emacs 22 or later to be installed. | |
5955 | ||
55f6ca0f JB |
5956 | @end itemize |
5957 | ||
d52fe014 | 5958 | @node Releasing GDB |
fb0ff88f | 5959 | |
d52fe014 AC |
5960 | @chapter Releasing @value{GDBN} |
5961 | @cindex making a new release of gdb | |
fb0ff88f | 5962 | |
9bb0a4d8 AC |
5963 | @section Branch Commit Policy |
5964 | ||
5965 | The branch commit policy is pretty slack. @value{GDBN} releases 5.0, | |
5966 | 5.1 and 5.2 all used the below: | |
5967 | ||
5968 | @itemize @bullet | |
5969 | @item | |
5970 | The @file{gdb/MAINTAINERS} file still holds. | |
5971 | @item | |
5972 | Don't fix something on the branch unless/until it is also fixed in the | |
5973 | trunk. If this isn't possible, mentioning it in the @file{gdb/PROBLEMS} | |
4be31470 | 5974 | file is better than committing a hack. |
9bb0a4d8 AC |
5975 | @item |
5976 | When considering a patch for the branch, suggested criteria include: | |
5977 | Does it fix a build? Does it fix the sequence @kbd{break main; run} | |
5978 | when debugging a static binary? | |
5979 | @item | |
5980 | The further a change is from the core of @value{GDBN}, the less likely | |
5981 | the change will worry anyone (e.g., target specific code). | |
5982 | @item | |
5983 | Only post a proposal to change the core of @value{GDBN} after you've | |
5984 | sent individual bribes to all the people listed in the | |
5985 | @file{MAINTAINERS} file @t{;-)} | |
5986 | @end itemize | |
5987 | ||
5988 | @emph{Pragmatics: Provided updates are restricted to non-core | |
5989 | functionality there is little chance that a broken change will be fatal. | |
5990 | This means that changes such as adding a new architectures or (within | |
5991 | reason) support for a new host are considered acceptable.} | |
5992 | ||
5993 | ||
cbb09e6a | 5994 | @section Obsoleting code |
8973da3a | 5995 | |
8642bc8f | 5996 | Before anything else, poke the other developers (and around the source |
4be31470 EZ |
5997 | code) to see if there is anything that can be removed from @value{GDBN} |
5998 | (an old target, an unused file). | |
8973da3a | 5999 | |
8642bc8f | 6000 | Obsolete code is identified by adding an @code{OBSOLETE} prefix to every |
cbb09e6a AC |
6001 | line. Doing this means that it is easy to identify something that has |
6002 | been obsoleted when greping through the sources. | |
8973da3a | 6003 | |
cbb09e6a AC |
6004 | The process is done in stages --- this is mainly to ensure that the |
6005 | wider @value{GDBN} community has a reasonable opportunity to respond. | |
6006 | Remember, everything on the Internet takes a week. | |
8973da3a | 6007 | |
cbb09e6a | 6008 | @enumerate |
8973da3a | 6009 | @item |
cbb09e6a AC |
6010 | Post the proposal on @email{gdb@@sources.redhat.com, the GDB mailing |
6011 | list} Creating a bug report to track the task's state, is also highly | |
6012 | recommended. | |
8973da3a | 6013 | @item |
cbb09e6a | 6014 | Wait a week or so. |
8973da3a | 6015 | @item |
cbb09e6a AC |
6016 | Post the proposal on @email{gdb-announce@@sources.redhat.com, the GDB |
6017 | Announcement mailing list}. | |
8973da3a | 6018 | @item |
cbb09e6a | 6019 | Wait a week or so. |
8973da3a | 6020 | @item |
cbb09e6a AC |
6021 | Go through and edit all relevant files and lines so that they are |
6022 | prefixed with the word @code{OBSOLETE}. | |
6023 | @item | |
6024 | Wait until the next GDB version, containing this obsolete code, has been | |
6025 | released. | |
6026 | @item | |
6027 | Remove the obsolete code. | |
6028 | @end enumerate | |
6029 | ||
6030 | @noindent | |
6031 | @emph{Maintainer note: While removing old code is regrettable it is | |
6032 | hopefully better for @value{GDBN}'s long term development. Firstly it | |
6033 | helps the developers by removing code that is either no longer relevant | |
6034 | or simply wrong. Secondly since it removes any history associated with | |
6035 | the file (effectively clearing the slate) the developer has a much freer | |
6036 | hand when it comes to fixing broken files.} | |
8973da3a | 6037 | |
8973da3a | 6038 | |
9ae8b82c AC |
6039 | |
6040 | @section Before the Branch | |
8973da3a | 6041 | |
8642bc8f AC |
6042 | The most important objective at this stage is to find and fix simple |
6043 | changes that become a pain to track once the branch is created. For | |
6044 | instance, configuration problems that stop @value{GDBN} from even | |
6045 | building. If you can't get the problem fixed, document it in the | |
6046 | @file{gdb/PROBLEMS} file. | |
8973da3a | 6047 | |
9ae8b82c | 6048 | @subheading Prompt for @file{gdb/NEWS} |
8973da3a | 6049 | |
9ae8b82c AC |
6050 | People always forget. Send a post reminding them but also if you know |
6051 | something interesting happened add it yourself. The @code{schedule} | |
6052 | script will mention this in its e-mail. | |
8973da3a | 6053 | |
9ae8b82c | 6054 | @subheading Review @file{gdb/README} |
8973da3a | 6055 | |
9ae8b82c AC |
6056 | Grab one of the nightly snapshots and then walk through the |
6057 | @file{gdb/README} looking for anything that can be improved. The | |
6058 | @code{schedule} script will mention this in its e-mail. | |
8642bc8f AC |
6059 | |
6060 | @subheading Refresh any imported files. | |
8973da3a | 6061 | |
8642bc8f | 6062 | A number of files are taken from external repositories. They include: |
8973da3a | 6063 | |
8642bc8f AC |
6064 | @itemize @bullet |
6065 | @item | |
6066 | @file{texinfo/texinfo.tex} | |
6067 | @item | |
9ae8b82c AC |
6068 | @file{config.guess} et.@: al.@: (see the top-level @file{MAINTAINERS} |
6069 | file) | |
6070 | @item | |
6071 | @file{etc/standards.texi}, @file{etc/make-stds.texi} | |
8642bc8f AC |
6072 | @end itemize |
6073 | ||
9ae8b82c | 6074 | @subheading Check the ARI |
8642bc8f | 6075 | |
9ae8b82c AC |
6076 | @uref{http://sources.redhat.com/gdb/ari,,A.R.I.} is an @code{awk} script |
6077 | (Awk Regression Index ;-) that checks for a number of errors and coding | |
6078 | conventions. The checks include things like using @code{malloc} instead | |
6079 | of @code{xmalloc} and file naming problems. There shouldn't be any | |
6080 | regressions. | |
8642bc8f | 6081 | |
9ae8b82c | 6082 | @subsection Review the bug data base |
8642bc8f | 6083 | |
9ae8b82c | 6084 | Close anything obviously fixed. |
8642bc8f | 6085 | |
9ae8b82c | 6086 | @subsection Check all cross targets build |
8642bc8f | 6087 | |
9ae8b82c | 6088 | The targets are listed in @file{gdb/MAINTAINERS}. |
8642bc8f | 6089 | |
8642bc8f | 6090 | |
30107679 | 6091 | @section Cut the Branch |
8642bc8f | 6092 | |
30107679 | 6093 | @subheading Create the branch |
8642bc8f | 6094 | |
474c8240 | 6095 | @smallexample |
30107679 AC |
6096 | $ u=5.1 |
6097 | $ v=5.2 | |
6098 | $ V=`echo $v | sed 's/\./_/g'` | |
6099 | $ D=`date -u +%Y-%m-%d` | |
6100 | $ echo $u $V $D | |
6101 | 5.1 5_2 2002-03-03 | |
6102 | $ echo cvs -f -d :ext:sources.redhat.com:/cvs/src rtag \ | |
b247355e | 6103 | -D $D-gmt gdb_$V-$D-branchpoint insight |
30107679 | 6104 | cvs -f -d :ext:sources.redhat.com:/cvs/src rtag |
b247355e | 6105 | -D 2002-03-03-gmt gdb_5_2-2002-03-03-branchpoint insight |
30107679 AC |
6106 | $ ^echo ^^ |
6107 | ... | |
6108 | $ echo cvs -f -d :ext:sources.redhat.com:/cvs/src rtag \ | |
b247355e | 6109 | -b -r gdb_$V-$D-branchpoint gdb_$V-branch insight |
30107679 | 6110 | cvs -f -d :ext:sources.redhat.com:/cvs/src rtag \ |
b247355e | 6111 | -b -r gdb_5_2-2002-03-03-branchpoint gdb_5_2-branch insight |
30107679 AC |
6112 | $ ^echo ^^ |
6113 | ... | |
8642bc8f | 6114 | $ |
474c8240 | 6115 | @end smallexample |
8642bc8f AC |
6116 | |
6117 | @itemize @bullet | |
6118 | @item | |
b247355e | 6119 | By using @kbd{-D YYYY-MM-DD-gmt}, the branch is forced to an exact |
30107679 AC |
6120 | date/time. |
6121 | @item | |
b247355e | 6122 | The trunk is first tagged so that the branch point can easily be found. |
30107679 | 6123 | @item |
b247355e | 6124 | Insight, which includes @value{GDBN}, is tagged at the same time. |
8642bc8f | 6125 | @item |
b247355e | 6126 | @file{version.in} gets bumped to avoid version number conflicts. |
8642bc8f | 6127 | @item |
b247355e | 6128 | The reading of @file{.cvsrc} is disabled using @file{-f}. |
30107679 AC |
6129 | @end itemize |
6130 | ||
6131 | @subheading Update @file{version.in} | |
6132 | ||
6133 | @smallexample | |
6134 | $ u=5.1 | |
6135 | $ v=5.2 | |
6136 | $ V=`echo $v | sed 's/\./_/g'` | |
6137 | $ echo $u $v$V | |
6138 | 5.1 5_2 | |
6139 | $ cd /tmp | |
6140 | $ echo cvs -f -d :ext:sources.redhat.com:/cvs/src co \ | |
6141 | -r gdb_$V-branch src/gdb/version.in | |
6142 | cvs -f -d :ext:sources.redhat.com:/cvs/src co | |
6143 | -r gdb_5_2-branch src/gdb/version.in | |
6144 | $ ^echo ^^ | |
6145 | U src/gdb/version.in | |
6146 | $ cd src/gdb | |
6147 | $ echo $u.90-0000-00-00-cvs > version.in | |
6148 | $ cat version.in | |
6149 | 5.1.90-0000-00-00-cvs | |
6150 | $ cvs -f commit version.in | |
6151 | @end smallexample | |
6152 | ||
6153 | @itemize @bullet | |
6154 | @item | |
6155 | @file{0000-00-00} is used as a date to pump prime the version.in update | |
b247355e | 6156 | mechanism. |
30107679 AC |
6157 | @item |
6158 | @file{.90} and the previous branch version are used as fairly arbitrary | |
b247355e | 6159 | initial branch version number. |
8642bc8f AC |
6160 | @end itemize |
6161 | ||
8642bc8f AC |
6162 | |
6163 | @subheading Update the web and news pages | |
6164 | ||
30107679 AC |
6165 | Something? |
6166 | ||
8642bc8f AC |
6167 | @subheading Tweak cron to track the new branch |
6168 | ||
30107679 AC |
6169 | The file @file{gdbadmin/cron/crontab} contains gdbadmin's cron table. |
6170 | This file needs to be updated so that: | |
6171 | ||
6172 | @itemize @bullet | |
6173 | @item | |
b247355e | 6174 | A daily timestamp is added to the file @file{version.in}. |
30107679 | 6175 | @item |
b247355e | 6176 | The new branch is included in the snapshot process. |
30107679 AC |
6177 | @end itemize |
6178 | ||
6179 | @noindent | |
6180 | See the file @file{gdbadmin/cron/README} for how to install the updated | |
6181 | cron table. | |
6182 | ||
6183 | The file @file{gdbadmin/ss/README} should also be reviewed to reflect | |
6184 | any changes. That file is copied to both the branch/ and current/ | |
6185 | snapshot directories. | |
6186 | ||
6187 | ||
6188 | @subheading Update the NEWS and README files | |
6189 | ||
6190 | The @file{NEWS} file needs to be updated so that on the branch it refers | |
6191 | to @emph{changes in the current release} while on the trunk it also | |
6192 | refers to @emph{changes since the current release}. | |
6193 | ||
6194 | The @file{README} file needs to be updated so that it refers to the | |
6195 | current release. | |
6196 | ||
6197 | @subheading Post the branch info | |
6198 | ||
6199 | Send an announcement to the mailing lists: | |
6200 | ||
6201 | @itemize @bullet | |
6202 | @item | |
6203 | @email{gdb-announce@@sources.redhat.com, GDB Announcement mailing list} | |
6204 | @item | |
d3e8051b EZ |
6205 | @email{gdb@@sources.redhat.com, GDB Discussion mailing list} and |
6206 | @email{gdb-testers@@sources.redhat.com, GDB Testers mailing list} | |
16737d73 | 6207 | @end itemize |
30107679 AC |
6208 | |
6209 | @emph{Pragmatics: The branch creation is sent to the announce list to | |
6210 | ensure that people people not subscribed to the higher volume discussion | |
6211 | list are alerted.} | |
6212 | ||
6213 | The announcement should include: | |
6214 | ||
6215 | @itemize @bullet | |
6216 | @item | |
b247355e | 6217 | The branch tag. |
30107679 | 6218 | @item |
b247355e | 6219 | How to check out the branch using CVS. |
30107679 | 6220 | @item |
b247355e | 6221 | The date/number of weeks until the release. |
30107679 | 6222 | @item |
b247355e | 6223 | The branch commit policy still holds. |
16737d73 | 6224 | @end itemize |
30107679 | 6225 | |
8642bc8f AC |
6226 | @section Stabilize the branch |
6227 | ||
6228 | Something goes here. | |
6229 | ||
6230 | @section Create a Release | |
6231 | ||
0816590b AC |
6232 | The process of creating and then making available a release is broken |
6233 | down into a number of stages. The first part addresses the technical | |
6234 | process of creating a releasable tar ball. The later stages address the | |
6235 | process of releasing that tar ball. | |
8973da3a | 6236 | |
0816590b AC |
6237 | When making a release candidate just the first section is needed. |
6238 | ||
6239 | @subsection Create a release candidate | |
6240 | ||
6241 | The objective at this stage is to create a set of tar balls that can be | |
6242 | made available as a formal release (or as a less formal release | |
6243 | candidate). | |
6244 | ||
6245 | @subsubheading Freeze the branch | |
6246 | ||
6247 | Send out an e-mail notifying everyone that the branch is frozen to | |
6248 | @email{gdb-patches@@sources.redhat.com}. | |
6249 | ||
6250 | @subsubheading Establish a few defaults. | |
8973da3a | 6251 | |
474c8240 | 6252 | @smallexample |
0816590b AC |
6253 | $ b=gdb_5_2-branch |
6254 | $ v=5.2 | |
8642bc8f AC |
6255 | $ t=/sourceware/snapshot-tmp/gdbadmin-tmp |
6256 | $ echo $t/$b/$v | |
0816590b | 6257 | /sourceware/snapshot-tmp/gdbadmin-tmp/gdb_5_2-branch/5.2 |
8642bc8f AC |
6258 | $ mkdir -p $t/$b/$v |
6259 | $ cd $t/$b/$v | |
6260 | $ pwd | |
0816590b | 6261 | /sourceware/snapshot-tmp/gdbadmin-tmp/gdb_5_2-branch/5.2 |
8973da3a AC |
6262 | $ which autoconf |
6263 | /home/gdbadmin/bin/autoconf | |
8642bc8f | 6264 | $ |
474c8240 | 6265 | @end smallexample |
8973da3a | 6266 | |
0816590b AC |
6267 | @noindent |
6268 | Notes: | |
8973da3a | 6269 | |
0816590b AC |
6270 | @itemize @bullet |
6271 | @item | |
6272 | Check the @code{autoconf} version carefully. You want to be using the | |
4a2b4636 JB |
6273 | version taken from the @file{binutils} snapshot directory, which can be |
6274 | found at @uref{ftp://sources.redhat.com/pub/binutils/}. It is very | |
0816590b AC |
6275 | unlikely that a system installed version of @code{autoconf} (e.g., |
6276 | @file{/usr/bin/autoconf}) is correct. | |
6277 | @end itemize | |
6278 | ||
6279 | @subsubheading Check out the relevant modules: | |
8973da3a | 6280 | |
474c8240 | 6281 | @smallexample |
b247355e | 6282 | $ for m in gdb insight |
8642bc8f | 6283 | do |
8973da3a AC |
6284 | ( mkdir -p $m && cd $m && cvs -q -f -d /cvs/src co -P -r $b $m ) |
6285 | done | |
8642bc8f | 6286 | $ |
474c8240 | 6287 | @end smallexample |
8973da3a | 6288 | |
0816590b AC |
6289 | @noindent |
6290 | Note: | |
8642bc8f | 6291 | |
0816590b AC |
6292 | @itemize @bullet |
6293 | @item | |
6294 | The reading of @file{.cvsrc} is disabled (@file{-f}) so that there isn't | |
6295 | any confusion between what is written here and what your local | |
6296 | @code{cvs} really does. | |
6297 | @end itemize | |
6298 | ||
6299 | @subsubheading Update relevant files. | |
8973da3a | 6300 | |
0816590b AC |
6301 | @table @file |
6302 | ||
6303 | @item gdb/NEWS | |
8642bc8f AC |
6304 | |
6305 | Major releases get their comments added as part of the mainline. Minor | |
6306 | releases should probably mention any significant bugs that were fixed. | |
6307 | ||
0816590b | 6308 | Don't forget to include the @file{ChangeLog} entry. |
8973da3a | 6309 | |
474c8240 | 6310 | @smallexample |
8642bc8f AC |
6311 | $ emacs gdb/src/gdb/NEWS |
6312 | ... | |
6313 | c-x 4 a | |
6314 | ... | |
6315 | c-x c-s c-x c-c | |
6316 | $ cp gdb/src/gdb/NEWS insight/src/gdb/NEWS | |
6317 | $ cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog | |
474c8240 | 6318 | @end smallexample |
8973da3a | 6319 | |
0816590b AC |
6320 | @item gdb/README |
6321 | ||
6322 | You'll need to update: | |
8973da3a | 6323 | |
0816590b AC |
6324 | @itemize @bullet |
6325 | @item | |
b247355e | 6326 | The version. |
0816590b | 6327 | @item |
b247355e | 6328 | The update date. |
0816590b | 6329 | @item |
b247355e | 6330 | Who did it. |
0816590b | 6331 | @end itemize |
8973da3a | 6332 | |
474c8240 | 6333 | @smallexample |
8642bc8f AC |
6334 | $ emacs gdb/src/gdb/README |
6335 | ... | |
8973da3a | 6336 | c-x 4 a |
8642bc8f | 6337 | ... |
8973da3a | 6338 | c-x c-s c-x c-c |
8642bc8f AC |
6339 | $ cp gdb/src/gdb/README insight/src/gdb/README |
6340 | $ cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog | |
474c8240 | 6341 | @end smallexample |
8973da3a | 6342 | |
0816590b AC |
6343 | @emph{Maintainer note: Hopefully the @file{README} file was reviewed |
6344 | before the initial branch was cut so just a simple substitute is needed | |
6345 | to get it updated.} | |
8973da3a | 6346 | |
8642bc8f AC |
6347 | @emph{Maintainer note: Other projects generate @file{README} and |
6348 | @file{INSTALL} from the core documentation. This might be worth | |
6349 | pursuing.} | |
8973da3a | 6350 | |
0816590b | 6351 | @item gdb/version.in |
8973da3a | 6352 | |
474c8240 | 6353 | @smallexample |
8642bc8f | 6354 | $ echo $v > gdb/src/gdb/version.in |
0816590b AC |
6355 | $ cat gdb/src/gdb/version.in |
6356 | 5.2 | |
8642bc8f | 6357 | $ emacs gdb/src/gdb/version.in |
8973da3a AC |
6358 | ... |
6359 | c-x 4 a | |
0816590b | 6360 | ... Bump to version ... |
8973da3a | 6361 | c-x c-s c-x c-c |
8642bc8f AC |
6362 | $ cp gdb/src/gdb/version.in insight/src/gdb/version.in |
6363 | $ cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog | |
474c8240 | 6364 | @end smallexample |
8973da3a | 6365 | |
0816590b AC |
6366 | @end table |
6367 | ||
6368 | @subsubheading Do the dirty work | |
6369 | ||
6370 | This is identical to the process used to create the daily snapshot. | |
8973da3a | 6371 | |
4ce8657e MC |
6372 | @smallexample |
6373 | $ for m in gdb insight | |
6374 | do | |
6375 | ( cd $m/src && gmake -f src-release $m.tar ) | |
6376 | done | |
4ce8657e MC |
6377 | @end smallexample |
6378 | ||
6379 | If the top level source directory does not have @file{src-release} | |
6380 | (@value{GDBN} version 5.3.1 or earlier), try these commands instead: | |
6381 | ||
474c8240 | 6382 | @smallexample |
0816590b | 6383 | $ for m in gdb insight |
8642bc8f | 6384 | do |
0816590b | 6385 | ( cd $m/src && gmake -f Makefile.in $m.tar ) |
8973da3a | 6386 | done |
474c8240 | 6387 | @end smallexample |
8973da3a | 6388 | |
0816590b | 6389 | @subsubheading Check the source files |
8642bc8f | 6390 | |
0816590b | 6391 | You're looking for files that have mysteriously disappeared. |
8642bc8f AC |
6392 | @kbd{distclean} has the habit of deleting files it shouldn't. Watch out |
6393 | for the @file{version.in} update @kbd{cronjob}. | |
8973da3a | 6394 | |
474c8240 | 6395 | @smallexample |
8642bc8f AC |
6396 | $ ( cd gdb/src && cvs -f -q -n update ) |
6397 | M djunpack.bat | |
0816590b | 6398 | ? gdb-5.1.91.tar |
8642bc8f | 6399 | ? proto-toplev |
0816590b | 6400 | @dots{} lots of generated files @dots{} |
8642bc8f AC |
6401 | M gdb/ChangeLog |
6402 | M gdb/NEWS | |
6403 | M gdb/README | |
6404 | M gdb/version.in | |
0816590b | 6405 | @dots{} lots of generated files @dots{} |
8642bc8f | 6406 | $ |
474c8240 | 6407 | @end smallexample |
8973da3a | 6408 | |
0816590b | 6409 | @noindent |
8642bc8f AC |
6410 | @emph{Don't worry about the @file{gdb.info-??} or |
6411 | @file{gdb/p-exp.tab.c}. They were generated (and yes @file{gdb.info-1} | |
6412 | was also generated only something strange with CVS means that they | |
d3e8051b | 6413 | didn't get suppressed). Fixing it would be nice though.} |
8973da3a | 6414 | |
0816590b | 6415 | @subsubheading Create compressed versions of the release |
8973da3a | 6416 | |
474c8240 | 6417 | @smallexample |
0816590b AC |
6418 | $ cp */src/*.tar . |
6419 | $ cp */src/*.bz2 . | |
6420 | $ ls -F | |
b247355e | 6421 | gdb/ gdb-5.2.tar insight/ insight-5.2.tar |
0816590b AC |
6422 | $ for m in gdb insight |
6423 | do | |
6424 | bzip2 -v -9 -c $m-$v.tar > $m-$v.tar.bz2 | |
6425 | gzip -v -9 -c $m-$v.tar > $m-$v.tar.gz | |
6426 | done | |
6427 | $ | |
474c8240 | 6428 | @end smallexample |
8973da3a | 6429 | |
0816590b AC |
6430 | @noindent |
6431 | Note: | |
6432 | ||
6433 | @itemize @bullet | |
6434 | @item | |
6435 | A pipe such as @kbd{bunzip2 < xxx.bz2 | gzip -9 > xxx.gz} is not since, | |
6436 | in that mode, @code{gzip} does not know the name of the file and, hence, | |
6437 | can not include it in the compressed file. This is also why the release | |
6438 | process runs @code{tar} and @code{bzip2} as separate passes. | |
6439 | @end itemize | |
6440 | ||
6441 | @subsection Sanity check the tar ball | |
8973da3a | 6442 | |
0816590b | 6443 | Pick a popular machine (Solaris/PPC?) and try the build on that. |
8973da3a | 6444 | |
0816590b AC |
6445 | @smallexample |
6446 | $ bunzip2 < gdb-5.2.tar.bz2 | tar xpf - | |
6447 | $ cd gdb-5.2 | |
6448 | $ ./configure | |
6449 | $ make | |
6450 | @dots{} | |
6451 | $ ./gdb/gdb ./gdb/gdb | |
6452 | GNU gdb 5.2 | |
6453 | @dots{} | |
6454 | (gdb) b main | |
6455 | Breakpoint 1 at 0x80732bc: file main.c, line 734. | |
6456 | (gdb) run | |
6457 | Starting program: /tmp/gdb-5.2/gdb/gdb | |
6458 | ||
6459 | Breakpoint 1, main (argc=1, argv=0xbffff8b4) at main.c:734 | |
6460 | 734 catch_errors (captured_main, &args, "", RETURN_MASK_ALL); | |
6461 | (gdb) print args | |
6462 | $1 = @{argc = 136426532, argv = 0x821b7f0@} | |
6463 | (gdb) | |
6464 | @end smallexample | |
8973da3a | 6465 | |
0816590b | 6466 | @subsection Make a release candidate available |
8973da3a | 6467 | |
0816590b | 6468 | If this is a release candidate then the only remaining steps are: |
8642bc8f | 6469 | |
0816590b AC |
6470 | @enumerate |
6471 | @item | |
6472 | Commit @file{version.in} and @file{ChangeLog} | |
6473 | @item | |
6474 | Tweak @file{version.in} (and @file{ChangeLog} to read | |
6475 | @var{L}.@var{M}.@var{N}-0000-00-00-cvs so that the version update | |
6476 | process can restart. | |
6477 | @item | |
6478 | Make the release candidate available in | |
6479 | @uref{ftp://sources.redhat.com/pub/gdb/snapshots/branch} | |
6480 | @item | |
6481 | Notify the relevant mailing lists ( @email{gdb@@sources.redhat.com} and | |
6482 | @email{gdb-testers@@sources.redhat.com} that the candidate is available. | |
6483 | @end enumerate | |
8642bc8f | 6484 | |
0816590b | 6485 | @subsection Make a formal release available |
8642bc8f | 6486 | |
0816590b | 6487 | (And you thought all that was required was to post an e-mail.) |
8642bc8f | 6488 | |
0816590b | 6489 | @subsubheading Install on sware |
8642bc8f | 6490 | |
0816590b | 6491 | Copy the new files to both the release and the old release directory: |
8642bc8f | 6492 | |
474c8240 | 6493 | @smallexample |
0816590b | 6494 | $ cp *.bz2 *.gz ~ftp/pub/gdb/old-releases/ |
8642bc8f | 6495 | $ cp *.bz2 *.gz ~ftp/pub/gdb/releases |
474c8240 | 6496 | @end smallexample |
8642bc8f | 6497 | |
0816590b AC |
6498 | @noindent |
6499 | Clean up the releases directory so that only the most recent releases | |
6500 | are available (e.g. keep 5.2 and 5.2.1 but remove 5.1): | |
6501 | ||
6502 | @smallexample | |
6503 | $ cd ~ftp/pub/gdb/releases | |
6504 | $ rm @dots{} | |
6505 | @end smallexample | |
6506 | ||
6507 | @noindent | |
6508 | Update the file @file{README} and @file{.message} in the releases | |
6509 | directory: | |
6510 | ||
6511 | @smallexample | |
6512 | $ vi README | |
6513 | @dots{} | |
6514 | $ rm -f .message | |
6515 | $ ln README .message | |
6516 | @end smallexample | |
8642bc8f | 6517 | |
0816590b | 6518 | @subsubheading Update the web pages. |
8973da3a | 6519 | |
0816590b AC |
6520 | @table @file |
6521 | ||
6522 | @item htdocs/download/ANNOUNCEMENT | |
6523 | This file, which is posted as the official announcement, includes: | |
8973da3a AC |
6524 | @itemize @bullet |
6525 | @item | |
b247355e | 6526 | General announcement. |
8642bc8f | 6527 | @item |
0816590b AC |
6528 | News. If making an @var{M}.@var{N}.1 release, retain the news from |
6529 | earlier @var{M}.@var{N} release. | |
8973da3a | 6530 | @item |
b247355e | 6531 | Errata. |
0816590b AC |
6532 | @end itemize |
6533 | ||
6534 | @item htdocs/index.html | |
6535 | @itemx htdocs/news/index.html | |
6536 | @itemx htdocs/download/index.html | |
6537 | These files include: | |
6538 | @itemize @bullet | |
8642bc8f | 6539 | @item |
b247355e | 6540 | Announcement of the most recent release. |
8642bc8f | 6541 | @item |
b247355e | 6542 | News entry (remember to update both the top level and the news directory). |
8973da3a | 6543 | @end itemize |
0816590b | 6544 | These pages also need to be regenerate using @code{index.sh}. |
8973da3a | 6545 | |
0816590b | 6546 | @item download/onlinedocs/ |
8642bc8f AC |
6547 | You need to find the magic command that is used to generate the online |
6548 | docs from the @file{.tar.bz2}. The best way is to look in the output | |
0816590b | 6549 | from one of the nightly @code{cron} jobs and then just edit accordingly. |
8642bc8f AC |
6550 | Something like: |
6551 | ||
474c8240 | 6552 | @smallexample |
8642bc8f | 6553 | $ ~/ss/update-web-docs \ |
0816590b | 6554 | ~ftp/pub/gdb/releases/gdb-5.2.tar.bz2 \ |
8642bc8f | 6555 | $PWD/www \ |
0816590b | 6556 | /www/sourceware/htdocs/gdb/download/onlinedocs \ |
8642bc8f | 6557 | gdb |
474c8240 | 6558 | @end smallexample |
8642bc8f | 6559 | |
0816590b AC |
6560 | @item download/ari/ |
6561 | Just like the online documentation. Something like: | |
8642bc8f | 6562 | |
0816590b AC |
6563 | @smallexample |
6564 | $ /bin/sh ~/ss/update-web-ari \ | |
6565 | ~ftp/pub/gdb/releases/gdb-5.2.tar.bz2 \ | |
6566 | $PWD/www \ | |
6567 | /www/sourceware/htdocs/gdb/download/ari \ | |
6568 | gdb | |
6569 | @end smallexample | |
6570 | ||
6571 | @end table | |
6572 | ||
6573 | @subsubheading Shadow the pages onto gnu | |
6574 | ||
6575 | Something goes here. | |
6576 | ||
6577 | ||
6578 | @subsubheading Install the @value{GDBN} tar ball on GNU | |
6579 | ||
6580 | At the time of writing, the GNU machine was @kbd{gnudist.gnu.org} in | |
6581 | @file{~ftp/gnu/gdb}. | |
6582 | ||
6583 | @subsubheading Make the @file{ANNOUNCEMENT} | |
6584 | ||
6585 | Post the @file{ANNOUNCEMENT} file you created above to: | |
8642bc8f AC |
6586 | |
6587 | @itemize @bullet | |
6588 | @item | |
6589 | @email{gdb-announce@@sources.redhat.com, GDB Announcement mailing list} | |
6590 | @item | |
0816590b AC |
6591 | @email{info-gnu@@gnu.org, General GNU Announcement list} (but delay it a |
6592 | day or so to let things get out) | |
6593 | @item | |
6594 | @email{bug-gdb@@gnu.org, GDB Bug Report mailing list} | |
8642bc8f AC |
6595 | @end itemize |
6596 | ||
0816590b | 6597 | @subsection Cleanup |
8642bc8f | 6598 | |
0816590b | 6599 | The release is out but you're still not finished. |
8642bc8f | 6600 | |
0816590b | 6601 | @subsubheading Commit outstanding changes |
8642bc8f | 6602 | |
0816590b | 6603 | In particular you'll need to commit any changes to: |
8642bc8f AC |
6604 | |
6605 | @itemize @bullet | |
6606 | @item | |
6607 | @file{gdb/ChangeLog} | |
6608 | @item | |
6609 | @file{gdb/version.in} | |
6610 | @item | |
6611 | @file{gdb/NEWS} | |
6612 | @item | |
6613 | @file{gdb/README} | |
6614 | @end itemize | |
6615 | ||
0816590b | 6616 | @subsubheading Tag the release |
8642bc8f AC |
6617 | |
6618 | Something like: | |
6619 | ||
474c8240 | 6620 | @smallexample |
8642bc8f AC |
6621 | $ d=`date -u +%Y-%m-%d` |
6622 | $ echo $d | |
6623 | 2002-01-24 | |
6624 | $ ( cd insight/src/gdb && cvs -f -q update ) | |
0816590b | 6625 | $ ( cd insight/src && cvs -f -q tag gdb_5_2-$d-release ) |
474c8240 | 6626 | @end smallexample |
8642bc8f | 6627 | |
0816590b | 6628 | Insight is used since that contains more of the release than |
b247355e | 6629 | @value{GDBN}. |
0816590b AC |
6630 | |
6631 | @subsubheading Mention the release on the trunk | |
8642bc8f | 6632 | |
0816590b AC |
6633 | Just put something in the @file{ChangeLog} so that the trunk also |
6634 | indicates when the release was made. | |
6635 | ||
6636 | @subsubheading Restart @file{gdb/version.in} | |
8642bc8f AC |
6637 | |
6638 | If @file{gdb/version.in} does not contain an ISO date such as | |
6639 | @kbd{2002-01-24} then the daily @code{cronjob} won't update it. Having | |
6640 | committed all the release changes it can be set to | |
0816590b | 6641 | @file{5.2.0_0000-00-00-cvs} which will restart things (yes the @kbd{_} |
8642bc8f AC |
6642 | is important - it affects the snapshot process). |
6643 | ||
6644 | Don't forget the @file{ChangeLog}. | |
6645 | ||
0816590b | 6646 | @subsubheading Merge into trunk |
8973da3a | 6647 | |
8642bc8f AC |
6648 | The files committed to the branch may also need changes merged into the |
6649 | trunk. | |
8973da3a | 6650 | |
0816590b AC |
6651 | @subsubheading Revise the release schedule |
6652 | ||
6653 | Post a revised release schedule to @email{gdb@@sources.redhat.com, GDB | |
6654 | Discussion List} with an updated announcement. The schedule can be | |
6655 | generated by running: | |
6656 | ||
6657 | @smallexample | |
6658 | $ ~/ss/schedule `date +%s` schedule | |
6659 | @end smallexample | |
6660 | ||
6661 | @noindent | |
6662 | The first parameter is approximate date/time in seconds (from the epoch) | |
6663 | of the most recent release. | |
6664 | ||
6665 | Also update the schedule @code{cronjob}. | |
6666 | ||
8642bc8f | 6667 | @section Post release |
8973da3a | 6668 | |
8642bc8f | 6669 | Remove any @code{OBSOLETE} code. |
8973da3a | 6670 | |
085dd6e6 JM |
6671 | @node Testsuite |
6672 | ||
6673 | @chapter Testsuite | |
56caf160 | 6674 | @cindex test suite |
085dd6e6 | 6675 | |
56caf160 EZ |
6676 | The testsuite is an important component of the @value{GDBN} package. |
6677 | While it is always worthwhile to encourage user testing, in practice | |
6678 | this is rarely sufficient; users typically use only a small subset of | |
6679 | the available commands, and it has proven all too common for a change | |
6680 | to cause a significant regression that went unnoticed for some time. | |
085dd6e6 | 6681 | |
b247355e NR |
6682 | The @value{GDBN} testsuite uses the DejaGNU testing framework. The |
6683 | tests themselves are calls to various @code{Tcl} procs; the framework | |
6684 | runs all the procs and summarizes the passes and fails. | |
085dd6e6 JM |
6685 | |
6686 | @section Using the Testsuite | |
6687 | ||
56caf160 | 6688 | @cindex running the test suite |
25822942 | 6689 | To run the testsuite, simply go to the @value{GDBN} object directory (or to the |
085dd6e6 JM |
6690 | testsuite's objdir) and type @code{make check}. This just sets up some |
6691 | environment variables and invokes DejaGNU's @code{runtest} script. While | |
6692 | the testsuite is running, you'll get mentions of which test file is in use, | |
6693 | and a mention of any unexpected passes or fails. When the testsuite is | |
6694 | finished, you'll get a summary that looks like this: | |
56caf160 | 6695 | |
474c8240 | 6696 | @smallexample |
085dd6e6 JM |
6697 | === gdb Summary === |
6698 | ||
6699 | # of expected passes 6016 | |
6700 | # of unexpected failures 58 | |
6701 | # of unexpected successes 5 | |
6702 | # of expected failures 183 | |
6703 | # of unresolved testcases 3 | |
6704 | # of untested testcases 5 | |
474c8240 | 6705 | @end smallexample |
56caf160 | 6706 | |
a9f158ec JB |
6707 | To run a specific test script, type: |
6708 | @example | |
6709 | make check RUNTESTFLAGS='@var{tests}' | |
6710 | @end example | |
6711 | where @var{tests} is a list of test script file names, separated by | |
6712 | spaces. | |
6713 | ||
085dd6e6 JM |
6714 | The ideal test run consists of expected passes only; however, reality |
6715 | conspires to keep us from this ideal. Unexpected failures indicate | |
56caf160 EZ |
6716 | real problems, whether in @value{GDBN} or in the testsuite. Expected |
6717 | failures are still failures, but ones which have been decided are too | |
6718 | hard to deal with at the time; for instance, a test case might work | |
6719 | everywhere except on AIX, and there is no prospect of the AIX case | |
6720 | being fixed in the near future. Expected failures should not be added | |
6721 | lightly, since you may be masking serious bugs in @value{GDBN}. | |
6722 | Unexpected successes are expected fails that are passing for some | |
6723 | reason, while unresolved and untested cases often indicate some minor | |
6724 | catastrophe, such as the compiler being unable to deal with a test | |
6725 | program. | |
6726 | ||
6727 | When making any significant change to @value{GDBN}, you should run the | |
6728 | testsuite before and after the change, to confirm that there are no | |
6729 | regressions. Note that truly complete testing would require that you | |
6730 | run the testsuite with all supported configurations and a variety of | |
6731 | compilers; however this is more than really necessary. In many cases | |
6732 | testing with a single configuration is sufficient. Other useful | |
6733 | options are to test one big-endian (Sparc) and one little-endian (x86) | |
6734 | host, a cross config with a builtin simulator (powerpc-eabi, | |
6735 | mips-elf), or a 64-bit host (Alpha). | |
6736 | ||
6737 | If you add new functionality to @value{GDBN}, please consider adding | |
6738 | tests for it as well; this way future @value{GDBN} hackers can detect | |
6739 | and fix their changes that break the functionality you added. | |
6740 | Similarly, if you fix a bug that was not previously reported as a test | |
6741 | failure, please add a test case for it. Some cases are extremely | |
6742 | difficult to test, such as code that handles host OS failures or bugs | |
6743 | in particular versions of compilers, and it's OK not to try to write | |
6744 | tests for all of those. | |
085dd6e6 | 6745 | |
e7dc800a MC |
6746 | DejaGNU supports separate build, host, and target machines. However, |
6747 | some @value{GDBN} test scripts do not work if the build machine and | |
6748 | the host machine are not the same. In such an environment, these scripts | |
6749 | will give a result of ``UNRESOLVED'', like this: | |
6750 | ||
6751 | @smallexample | |
6752 | UNRESOLVED: gdb.base/example.exp: This test script does not work on a remote host. | |
6753 | @end smallexample | |
6754 | ||
085dd6e6 JM |
6755 | @section Testsuite Organization |
6756 | ||
56caf160 | 6757 | @cindex test suite organization |
085dd6e6 JM |
6758 | The testsuite is entirely contained in @file{gdb/testsuite}. While the |
6759 | testsuite includes some makefiles and configury, these are very minimal, | |
6760 | and used for little besides cleaning up, since the tests themselves | |
25822942 | 6761 | handle the compilation of the programs that @value{GDBN} will run. The file |
085dd6e6 | 6762 | @file{testsuite/lib/gdb.exp} contains common utility procs useful for |
25822942 | 6763 | all @value{GDBN} tests, while the directory @file{testsuite/config} contains |
085dd6e6 JM |
6764 | configuration-specific files, typically used for special-purpose |
6765 | definitions of procs like @code{gdb_load} and @code{gdb_start}. | |
6766 | ||
6767 | The tests themselves are to be found in @file{testsuite/gdb.*} and | |
6768 | subdirectories of those. The names of the test files must always end | |
6769 | with @file{.exp}. DejaGNU collects the test files by wildcarding | |
6770 | in the test directories, so both subdirectories and individual files | |
6771 | get chosen and run in alphabetical order. | |
6772 | ||
6773 | The following table lists the main types of subdirectories and what they | |
6774 | are for. Since DejaGNU finds test files no matter where they are | |
6775 | located, and since each test file sets up its own compilation and | |
6776 | execution environment, this organization is simply for convenience and | |
6777 | intelligibility. | |
6778 | ||
56caf160 | 6779 | @table @file |
085dd6e6 | 6780 | @item gdb.base |
085dd6e6 | 6781 | This is the base testsuite. The tests in it should apply to all |
25822942 | 6782 | configurations of @value{GDBN} (but generic native-only tests may live here). |
085dd6e6 | 6783 | The test programs should be in the subset of C that is valid K&R, |
49efadf5 | 6784 | ANSI/ISO, and C@t{++} (@code{#ifdef}s are allowed if necessary, for instance |
085dd6e6 JM |
6785 | for prototypes). |
6786 | ||
6787 | @item gdb.@var{lang} | |
56caf160 | 6788 | Language-specific tests for any language @var{lang} besides C. Examples are |
af6cf26d | 6789 | @file{gdb.cp} and @file{gdb.java}. |
085dd6e6 JM |
6790 | |
6791 | @item gdb.@var{platform} | |
085dd6e6 JM |
6792 | Non-portable tests. The tests are specific to a specific configuration |
6793 | (host or target), such as HP-UX or eCos. Example is @file{gdb.hp}, for | |
6794 | HP-UX. | |
6795 | ||
6796 | @item gdb.@var{compiler} | |
085dd6e6 JM |
6797 | Tests specific to a particular compiler. As of this writing (June |
6798 | 1999), there aren't currently any groups of tests in this category that | |
6799 | couldn't just as sensibly be made platform-specific, but one could | |
56caf160 EZ |
6800 | imagine a @file{gdb.gcc}, for tests of @value{GDBN}'s handling of GCC |
6801 | extensions. | |
085dd6e6 JM |
6802 | |
6803 | @item gdb.@var{subsystem} | |
25822942 | 6804 | Tests that exercise a specific @value{GDBN} subsystem in more depth. For |
085dd6e6 JM |
6805 | instance, @file{gdb.disasm} exercises various disassemblers, while |
6806 | @file{gdb.stabs} tests pathways through the stabs symbol reader. | |
085dd6e6 JM |
6807 | @end table |
6808 | ||
6809 | @section Writing Tests | |
56caf160 | 6810 | @cindex writing tests |
085dd6e6 | 6811 | |
25822942 | 6812 | In many areas, the @value{GDBN} tests are already quite comprehensive; you |
085dd6e6 JM |
6813 | should be able to copy existing tests to handle new cases. |
6814 | ||
6815 | You should try to use @code{gdb_test} whenever possible, since it | |
6816 | includes cases to handle all the unexpected errors that might happen. | |
6817 | However, it doesn't cost anything to add new test procedures; for | |
6818 | instance, @file{gdb.base/exprs.exp} defines a @code{test_expr} that | |
6819 | calls @code{gdb_test} multiple times. | |
6820 | ||
6821 | Only use @code{send_gdb} and @code{gdb_expect} when absolutely | |
8a3dae3e DJ |
6822 | necessary. Even if @value{GDBN} has several valid responses to |
6823 | a command, you can use @code{gdb_test_multiple}. Like @code{gdb_test}, | |
6824 | @code{gdb_test_multiple} recognizes internal errors and unexpected | |
6825 | prompts. | |
6826 | ||
6827 | Do not write tests which expect a literal tab character from @value{GDBN}. | |
6828 | On some operating systems (e.g.@: OpenBSD) the TTY layer expands tabs to | |
6829 | spaces, so by the time @value{GDBN}'s output reaches expect the tab is gone. | |
085dd6e6 JM |
6830 | |
6831 | The source language programs do @emph{not} need to be in a consistent | |
25822942 | 6832 | style. Since @value{GDBN} is used to debug programs written in many different |
085dd6e6 | 6833 | styles, it's worth having a mix of styles in the testsuite; for |
25822942 | 6834 | instance, some @value{GDBN} bugs involving the display of source lines would |
085dd6e6 JM |
6835 | never manifest themselves if the programs used GNU coding style |
6836 | uniformly. | |
6837 | ||
c906108c SS |
6838 | @node Hints |
6839 | ||
6840 | @chapter Hints | |
6841 | ||
6842 | Check the @file{README} file, it often has useful information that does not | |
6843 | appear anywhere else in the directory. | |
6844 | ||
6845 | @menu | |
25822942 | 6846 | * Getting Started:: Getting started working on @value{GDBN} |
33e16fad | 6847 | * Debugging GDB:: Debugging @value{GDBN} with itself |
c906108c SS |
6848 | @end menu |
6849 | ||
6850 | @node Getting Started,,, Hints | |
6851 | ||
6852 | @section Getting Started | |
6853 | ||
25822942 | 6854 | @value{GDBN} is a large and complicated program, and if you first starting to |
c906108c SS |
6855 | work on it, it can be hard to know where to start. Fortunately, if you |
6856 | know how to go about it, there are ways to figure out what is going on. | |
6857 | ||
25822942 DB |
6858 | This manual, the @value{GDBN} Internals manual, has information which applies |
6859 | generally to many parts of @value{GDBN}. | |
c906108c SS |
6860 | |
6861 | Information about particular functions or data structures are located in | |
6862 | comments with those functions or data structures. If you run across a | |
6863 | function or a global variable which does not have a comment correctly | |
25822942 | 6864 | explaining what is does, this can be thought of as a bug in @value{GDBN}; feel |
c906108c SS |
6865 | free to submit a bug report, with a suggested comment if you can figure |
6866 | out what the comment should say. If you find a comment which is | |
6867 | actually wrong, be especially sure to report that. | |
6868 | ||
6869 | Comments explaining the function of macros defined in host, target, or | |
6870 | native dependent files can be in several places. Sometimes they are | |
6871 | repeated every place the macro is defined. Sometimes they are where the | |
6872 | macro is used. Sometimes there is a header file which supplies a | |
6873 | default definition of the macro, and the comment is there. This manual | |
6874 | also documents all the available macros. | |
6875 | @c (@pxref{Host Conditionals}, @pxref{Target | |
6876 | @c Conditionals}, @pxref{Native Conditionals}, and @pxref{Obsolete | |
6877 | @c Conditionals}) | |
6878 | ||
56caf160 EZ |
6879 | Start with the header files. Once you have some idea of how |
6880 | @value{GDBN}'s internal symbol tables are stored (see @file{symtab.h}, | |
6881 | @file{gdbtypes.h}), you will find it much easier to understand the | |
6882 | code which uses and creates those symbol tables. | |
c906108c SS |
6883 | |
6884 | You may wish to process the information you are getting somehow, to | |
6885 | enhance your understanding of it. Summarize it, translate it to another | |
25822942 | 6886 | language, add some (perhaps trivial or non-useful) feature to @value{GDBN}, use |
c906108c SS |
6887 | the code to predict what a test case would do and write the test case |
6888 | and verify your prediction, etc. If you are reading code and your eyes | |
6889 | are starting to glaze over, this is a sign you need to use a more active | |
6890 | approach. | |
6891 | ||
25822942 | 6892 | Once you have a part of @value{GDBN} to start with, you can find more |
c906108c SS |
6893 | specifically the part you are looking for by stepping through each |
6894 | function with the @code{next} command. Do not use @code{step} or you | |
6895 | will quickly get distracted; when the function you are stepping through | |
6896 | calls another function try only to get a big-picture understanding | |
6897 | (perhaps using the comment at the beginning of the function being | |
6898 | called) of what it does. This way you can identify which of the | |
6899 | functions being called by the function you are stepping through is the | |
6900 | one which you are interested in. You may need to examine the data | |
6901 | structures generated at each stage, with reference to the comments in | |
6902 | the header files explaining what the data structures are supposed to | |
6903 | look like. | |
6904 | ||
6905 | Of course, this same technique can be used if you are just reading the | |
6906 | code, rather than actually stepping through it. The same general | |
6907 | principle applies---when the code you are looking at calls something | |
6908 | else, just try to understand generally what the code being called does, | |
6909 | rather than worrying about all its details. | |
6910 | ||
56caf160 EZ |
6911 | @cindex command implementation |
6912 | A good place to start when tracking down some particular area is with | |
6913 | a command which invokes that feature. Suppose you want to know how | |
6914 | single-stepping works. As a @value{GDBN} user, you know that the | |
6915 | @code{step} command invokes single-stepping. The command is invoked | |
6916 | via command tables (see @file{command.h}); by convention the function | |
6917 | which actually performs the command is formed by taking the name of | |
6918 | the command and adding @samp{_command}, or in the case of an | |
6919 | @code{info} subcommand, @samp{_info}. For example, the @code{step} | |
6920 | command invokes the @code{step_command} function and the @code{info | |
6921 | display} command invokes @code{display_info}. When this convention is | |
6922 | not followed, you might have to use @code{grep} or @kbd{M-x | |
6923 | tags-search} in emacs, or run @value{GDBN} on itself and set a | |
6924 | breakpoint in @code{execute_command}. | |
6925 | ||
6926 | @cindex @code{bug-gdb} mailing list | |
c906108c SS |
6927 | If all of the above fail, it may be appropriate to ask for information |
6928 | on @code{bug-gdb}. But @emph{never} post a generic question like ``I was | |
6929 | wondering if anyone could give me some tips about understanding | |
25822942 | 6930 | @value{GDBN}''---if we had some magic secret we would put it in this manual. |
c906108c SS |
6931 | Suggestions for improving the manual are always welcome, of course. |
6932 | ||
33e16fad | 6933 | @node Debugging GDB,,,Hints |
c906108c | 6934 | |
25822942 | 6935 | @section Debugging @value{GDBN} with itself |
56caf160 | 6936 | @cindex debugging @value{GDBN} |
c906108c | 6937 | |
25822942 | 6938 | If @value{GDBN} is limping on your machine, this is the preferred way to get it |
c906108c SS |
6939 | fully functional. Be warned that in some ancient Unix systems, like |
6940 | Ultrix 4.2, a program can't be running in one process while it is being | |
56caf160 | 6941 | debugged in another. Rather than typing the command @kbd{@w{./gdb |
c906108c | 6942 | ./gdb}}, which works on Suns and such, you can copy @file{gdb} to |
56caf160 | 6943 | @file{gdb2} and then type @kbd{@w{./gdb ./gdb2}}. |
c906108c | 6944 | |
25822942 | 6945 | When you run @value{GDBN} in the @value{GDBN} source directory, it will read a |
c906108c SS |
6946 | @file{.gdbinit} file that sets up some simple things to make debugging |
6947 | gdb easier. The @code{info} command, when executed without a subcommand | |
25822942 | 6948 | in a @value{GDBN} being debugged by gdb, will pop you back up to the top level |
c906108c SS |
6949 | gdb. See @file{.gdbinit} for details. |
6950 | ||
6951 | If you use emacs, you will probably want to do a @code{make TAGS} after | |
6952 | you configure your distribution; this will put the machine dependent | |
6953 | routines for your local machine where they will be accessed first by | |
6954 | @kbd{M-.} | |
6955 | ||
25822942 | 6956 | Also, make sure that you've either compiled @value{GDBN} with your local cc, or |
c906108c SS |
6957 | have run @code{fixincludes} if you are compiling with gcc. |
6958 | ||
6959 | @section Submitting Patches | |
6960 | ||
56caf160 | 6961 | @cindex submitting patches |
c906108c | 6962 | Thanks for thinking of offering your changes back to the community of |
25822942 | 6963 | @value{GDBN} users. In general we like to get well designed enhancements. |
c906108c SS |
6964 | Thanks also for checking in advance about the best way to transfer the |
6965 | changes. | |
6966 | ||
25822942 DB |
6967 | The @value{GDBN} maintainers will only install ``cleanly designed'' patches. |
6968 | This manual summarizes what we believe to be clean design for @value{GDBN}. | |
c906108c SS |
6969 | |
6970 | If the maintainers don't have time to put the patch in when it arrives, | |
6971 | or if there is any question about a patch, it goes into a large queue | |
6972 | with everyone else's patches and bug reports. | |
6973 | ||
56caf160 | 6974 | @cindex legal papers for code contributions |
c906108c SS |
6975 | The legal issue is that to incorporate substantial changes requires a |
6976 | copyright assignment from you and/or your employer, granting ownership | |
6977 | of the changes to the Free Software Foundation. You can get the | |
9e0b60a8 JM |
6978 | standard documents for doing this by sending mail to @code{gnu@@gnu.org} |
6979 | and asking for it. We recommend that people write in "All programs | |
6980 | owned by the Free Software Foundation" as "NAME OF PROGRAM", so that | |
56caf160 EZ |
6981 | changes in many programs (not just @value{GDBN}, but GAS, Emacs, GCC, |
6982 | etc) can be | |
9e0b60a8 | 6983 | contributed with only one piece of legalese pushed through the |
be9c6c35 | 6984 | bureaucracy and filed with the FSF. We can't start merging changes until |
9e0b60a8 JM |
6985 | this paperwork is received by the FSF (their rules, which we follow |
6986 | since we maintain it for them). | |
c906108c SS |
6987 | |
6988 | Technically, the easiest way to receive changes is to receive each | |
56caf160 EZ |
6989 | feature as a small context diff or unidiff, suitable for @code{patch}. |
6990 | Each message sent to me should include the changes to C code and | |
6991 | header files for a single feature, plus @file{ChangeLog} entries for | |
6992 | each directory where files were modified, and diffs for any changes | |
6993 | needed to the manuals (@file{gdb/doc/gdb.texinfo} or | |
6994 | @file{gdb/doc/gdbint.texinfo}). If there are a lot of changes for a | |
6995 | single feature, they can be split down into multiple messages. | |
9e0b60a8 JM |
6996 | |
6997 | In this way, if we read and like the feature, we can add it to the | |
c906108c | 6998 | sources with a single patch command, do some testing, and check it in. |
56caf160 EZ |
6999 | If you leave out the @file{ChangeLog}, we have to write one. If you leave |
7000 | out the doc, we have to puzzle out what needs documenting. Etc., etc. | |
c906108c | 7001 | |
9e0b60a8 JM |
7002 | The reason to send each change in a separate message is that we will not |
7003 | install some of the changes. They'll be returned to you with questions | |
7004 | or comments. If we're doing our job correctly, the message back to you | |
c906108c | 7005 | will say what you have to fix in order to make the change acceptable. |
9e0b60a8 JM |
7006 | The reason to have separate messages for separate features is so that |
7007 | the acceptable changes can be installed while one or more changes are | |
7008 | being reworked. If multiple features are sent in a single message, we | |
7009 | tend to not put in the effort to sort out the acceptable changes from | |
7010 | the unacceptable, so none of the features get installed until all are | |
7011 | acceptable. | |
7012 | ||
7013 | If this sounds painful or authoritarian, well, it is. But we get a lot | |
7014 | of bug reports and a lot of patches, and many of them don't get | |
7015 | installed because we don't have the time to finish the job that the bug | |
c906108c SS |
7016 | reporter or the contributor could have done. Patches that arrive |
7017 | complete, working, and well designed, tend to get installed on the day | |
9e0b60a8 JM |
7018 | they arrive. The others go into a queue and get installed as time |
7019 | permits, which, since the maintainers have many demands to meet, may not | |
7020 | be for quite some time. | |
c906108c | 7021 | |
56caf160 | 7022 | Please send patches directly to |
47b95330 | 7023 | @email{gdb-patches@@sources.redhat.com, the @value{GDBN} maintainers}. |
c906108c | 7024 | |
36af4ef6 MD |
7025 | @section Build Script |
7026 | ||
7027 | @cindex build script | |
7028 | ||
7029 | The script @file{gdb_buildall.sh} builds @value{GDBN} with flag | |
7030 | @option{--enable-targets=all} set. This builds @value{GDBN} with all supported | |
7031 | targets activated. This helps testing @value{GDBN} when doing changes that | |
7032 | affect more than one architecture and is much faster than using | |
7033 | @file{gdb_mbuild.sh}. | |
7034 | ||
7035 | After building @value{GDBN} the script checks which architectures are | |
7036 | supported and then switches the current architecture to each of those to get | |
7037 | information about the architecture. The test results are stored in log files | |
7038 | in the directory the script was called from. | |
7039 | ||
bcd7e15f | 7040 | @include observer.texi |
2154891a | 7041 | @raisesections |
aab4e0ec | 7042 | @include fdl.texi |
2154891a | 7043 | @lowersections |
aab4e0ec | 7044 | |
56caf160 EZ |
7045 | @node Index |
7046 | @unnumbered Index | |
7047 | ||
7048 | @printindex cp | |
7049 | ||
c906108c | 7050 | @bye |