1 /* Get info from stack frames; convert between frames, blocks,
2 functions and pc values.
4 Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
5 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 Free Software
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to the Free Software
22 Foundation, Inc., 59 Temple Place - Suite 330,
23 Boston, MA 02111-1307, USA. */
32 #include "value.h" /* for read_register */
33 #include "target.h" /* for target_has_stack */
34 #include "inferior.h" /* for read_pc */
37 #include "gdb_assert.h"
38 #include "dummy-frame.h"
43 /* Prototypes for exported functions. */
45 void _initialize_blockframe (void);
47 /* Is ADDR inside the startup file? Note that if your machine has a
48 way to detect the bottom of the stack, there is no need to call
49 this function from DEPRECATED_FRAME_CHAIN_VALID; the reason for
50 doing so is that some machines have no way of detecting bottom of
53 A PC of zero is always considered to be the bottom of the stack. */
56 inside_entry_file (CORE_ADDR addr
)
60 if (symfile_objfile
== 0)
62 if (CALL_DUMMY_LOCATION
== AT_ENTRY_POINT
)
64 /* Do not stop backtracing if the pc is in the call dummy
65 at the entry point. */
66 /* FIXME: Won't always work with zeros for the last two arguments */
67 if (DEPRECATED_PC_IN_CALL_DUMMY (addr
, 0, 0))
70 return (addr
>= symfile_objfile
->ei
.entry_file_lowpc
&&
71 addr
< symfile_objfile
->ei
.entry_file_highpc
);
74 /* Test a specified PC value to see if it is in the range of addresses
75 that correspond to the main() function. See comments above for why
76 we might want to do this.
78 Typically called from DEPRECATED_FRAME_CHAIN_VALID.
80 A PC of zero is always considered to be the bottom of the stack. */
83 inside_main_func (CORE_ADDR pc
)
87 if (symfile_objfile
== 0)
90 /* If the addr range is not set up at symbol reading time, set it up
91 now. This is for DEPRECATED_FRAME_CHAIN_VALID_ALTERNATE. I do
92 this for coff, because it is unable to set it up and symbol
95 if (symfile_objfile
->ei
.main_func_lowpc
== INVALID_ENTRY_LOWPC
&&
96 symfile_objfile
->ei
.main_func_highpc
== INVALID_ENTRY_HIGHPC
)
98 struct symbol
*mainsym
;
100 mainsym
= lookup_symbol (main_name (), NULL
, VAR_NAMESPACE
, NULL
, NULL
);
101 if (mainsym
&& SYMBOL_CLASS (mainsym
) == LOC_BLOCK
)
103 symfile_objfile
->ei
.main_func_lowpc
=
104 BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym
));
105 symfile_objfile
->ei
.main_func_highpc
=
106 BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym
));
109 return (symfile_objfile
->ei
.main_func_lowpc
<= pc
&&
110 symfile_objfile
->ei
.main_func_highpc
> pc
);
113 /* Test a specified PC value to see if it is in the range of addresses
114 that correspond to the process entry point function. See comments
115 in objfiles.h for why we might want to do this.
117 Typically called from DEPRECATED_FRAME_CHAIN_VALID.
119 A PC of zero is always considered to be the bottom of the stack. */
122 inside_entry_func (CORE_ADDR pc
)
126 if (symfile_objfile
== 0)
128 if (CALL_DUMMY_LOCATION
== AT_ENTRY_POINT
)
130 /* Do not stop backtracing if the pc is in the call dummy
131 at the entry point. */
132 /* FIXME: Won't always work with zeros for the last two arguments */
133 if (DEPRECATED_PC_IN_CALL_DUMMY (pc
, 0, 0))
136 return (symfile_objfile
->ei
.entry_func_lowpc
<= pc
&&
137 symfile_objfile
->ei
.entry_func_highpc
> pc
);
140 /* Return nonzero if the function for this frame lacks a prologue. Many
141 machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
145 frameless_look_for_prologue (struct frame_info
*frame
)
147 CORE_ADDR func_start
, after_prologue
;
149 func_start
= get_frame_func (frame
);
152 func_start
+= FUNCTION_START_OFFSET
;
153 /* This is faster, since only care whether there *is* a
154 prologue, not how long it is. */
155 return PROLOGUE_FRAMELESS_P (func_start
);
157 else if (get_frame_pc (frame
) == 0)
158 /* A frame with a zero PC is usually created by dereferencing a
159 NULL function pointer, normally causing an immediate core dump
160 of the inferior. Mark function as frameless, as the inferior
161 has no chance of setting up a stack frame. */
164 /* If we can't find the start of the function, we don't really
165 know whether the function is frameless, but we should be able
166 to get a reasonable (i.e. best we can do under the
167 circumstances) backtrace by saying that it isn't. */
171 /* return the address of the PC for the given FRAME, ie the current PC value
172 if FRAME is the innermost frame, or the address adjusted to point to the
173 call instruction if not. */
176 frame_address_in_block (struct frame_info
*frame
)
178 CORE_ADDR pc
= get_frame_pc (frame
);
180 /* If we are not in the innermost frame, and we are not interrupted
181 by a signal, frame->pc points to the instruction following the
182 call. As a consequence, we need to get the address of the previous
183 instruction. Unfortunately, this is not straightforward to do, so
184 we just use the address minus one, which is a good enough
186 /* FIXME: cagney/2002-11-10: Should this instead test for
187 NORMAL_FRAME? A dummy frame (in fact all the abnormal frames)
188 save the PC value in the block. */
189 if (get_next_frame (frame
) != 0
190 && get_frame_type (get_next_frame (frame
)) != SIGTRAMP_FRAME
)
196 /* Return the innermost lexical block in execution
197 in a specified stack frame. The frame address is assumed valid.
199 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
200 address we used to choose the block. We use this to find a source
201 line, to decide which macro definitions are in scope.
203 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
204 PC, and may not really be a valid PC at all. For example, in the
205 caller of a function declared to never return, the code at the
206 return address will never be reached, so the call instruction may
207 be the very last instruction in the block. So the address we use
208 to choose the block is actually one byte before the return address
209 --- hopefully pointing us at the call instruction, or its delay
213 get_frame_block (struct frame_info
*frame
, CORE_ADDR
*addr_in_block
)
215 const CORE_ADDR pc
= frame_address_in_block (frame
);
220 return block_for_pc (pc
);
224 get_pc_function_start (CORE_ADDR pc
)
226 register struct block
*bl
;
227 register struct symbol
*symbol
;
228 register struct minimal_symbol
*msymbol
;
231 if ((bl
= block_for_pc (pc
)) != NULL
&&
232 (symbol
= block_function (bl
)) != NULL
)
234 bl
= SYMBOL_BLOCK_VALUE (symbol
);
235 fstart
= BLOCK_START (bl
);
237 else if ((msymbol
= lookup_minimal_symbol_by_pc (pc
)) != NULL
)
239 fstart
= SYMBOL_VALUE_ADDRESS (msymbol
);
240 if (!find_pc_section (fstart
))
250 /* Return the symbol for the function executing in frame FRAME. */
253 get_frame_function (struct frame_info
*frame
)
255 register struct block
*bl
= get_frame_block (frame
, 0);
258 return block_function (bl
);
262 /* Return the function containing pc value PC in section SECTION.
263 Returns 0 if function is not known. */
266 find_pc_sect_function (CORE_ADDR pc
, struct sec
*section
)
268 register struct block
*b
= block_for_pc_sect (pc
, section
);
271 return block_function (b
);
274 /* Return the function containing pc value PC.
275 Returns 0 if function is not known. Backward compatibility, no section */
278 find_pc_function (CORE_ADDR pc
)
280 return find_pc_sect_function (pc
, find_pc_mapped_section (pc
));
283 /* These variables are used to cache the most recent result
284 * of find_pc_partial_function. */
286 static CORE_ADDR cache_pc_function_low
= 0;
287 static CORE_ADDR cache_pc_function_high
= 0;
288 static char *cache_pc_function_name
= 0;
289 static struct sec
*cache_pc_function_section
= NULL
;
291 /* Clear cache, e.g. when symbol table is discarded. */
294 clear_pc_function_cache (void)
296 cache_pc_function_low
= 0;
297 cache_pc_function_high
= 0;
298 cache_pc_function_name
= (char *) 0;
299 cache_pc_function_section
= NULL
;
302 /* Finds the "function" (text symbol) that is smaller than PC but
303 greatest of all of the potential text symbols in SECTION. Sets
304 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
305 If ENDADDR is non-null, then set *ENDADDR to be the end of the
306 function (exclusive), but passing ENDADDR as non-null means that
307 the function might cause symbols to be read. This function either
308 succeeds or fails (not halfway succeeds). If it succeeds, it sets
309 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
310 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
314 find_pc_sect_partial_function (CORE_ADDR pc
, asection
*section
, char **name
,
315 CORE_ADDR
*address
, CORE_ADDR
*endaddr
)
317 struct partial_symtab
*pst
;
319 struct minimal_symbol
*msymbol
;
320 struct partial_symbol
*psb
;
321 struct obj_section
*osect
;
325 mapped_pc
= overlay_mapped_address (pc
, section
);
327 if (mapped_pc
>= cache_pc_function_low
328 && mapped_pc
< cache_pc_function_high
329 && section
== cache_pc_function_section
)
330 goto return_cached_value
;
332 /* If sigtramp is in the u area, it counts as a function (especially
333 important for step_1). */
334 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc
, (char *) NULL
))
336 cache_pc_function_low
= SIGTRAMP_START (mapped_pc
);
337 cache_pc_function_high
= SIGTRAMP_END (mapped_pc
);
338 cache_pc_function_name
= "<sigtramp>";
339 cache_pc_function_section
= section
;
340 goto return_cached_value
;
343 msymbol
= lookup_minimal_symbol_by_pc_section (mapped_pc
, section
);
344 pst
= find_pc_sect_psymtab (mapped_pc
, section
);
347 /* Need to read the symbols to get a good value for the end address. */
348 if (endaddr
!= NULL
&& !pst
->readin
)
350 /* Need to get the terminal in case symbol-reading produces
352 target_terminal_ours_for_output ();
353 PSYMTAB_TO_SYMTAB (pst
);
358 /* Checking whether the msymbol has a larger value is for the
359 "pathological" case mentioned in print_frame_info. */
360 f
= find_pc_sect_function (mapped_pc
, section
);
363 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f
))
364 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
366 cache_pc_function_low
= BLOCK_START (SYMBOL_BLOCK_VALUE (f
));
367 cache_pc_function_high
= BLOCK_END (SYMBOL_BLOCK_VALUE (f
));
368 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (f
);
369 cache_pc_function_section
= section
;
370 goto return_cached_value
;
375 /* Now that static symbols go in the minimal symbol table, perhaps
376 we could just ignore the partial symbols. But at least for now
377 we use the partial or minimal symbol, whichever is larger. */
378 psb
= find_pc_sect_psymbol (pst
, mapped_pc
, section
);
381 && (msymbol
== NULL
||
382 (SYMBOL_VALUE_ADDRESS (psb
)
383 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
385 /* This case isn't being cached currently. */
387 *address
= SYMBOL_VALUE_ADDRESS (psb
);
389 *name
= DEPRECATED_SYMBOL_NAME (psb
);
390 /* endaddr non-NULL can't happen here. */
396 /* Not in the normal symbol tables, see if the pc is in a known section.
397 If it's not, then give up. This ensures that anything beyond the end
398 of the text seg doesn't appear to be part of the last function in the
401 osect
= find_pc_sect_section (mapped_pc
, section
);
406 /* Must be in the minimal symbol table. */
409 /* No available symbol. */
419 cache_pc_function_low
= SYMBOL_VALUE_ADDRESS (msymbol
);
420 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (msymbol
);
421 cache_pc_function_section
= section
;
423 /* Use the lesser of the next minimal symbol in the same section, or
424 the end of the section, as the end of the function. */
426 /* Step over other symbols at this same address, and symbols in
427 other sections, to find the next symbol in this section with
428 a different address. */
430 for (i
= 1; DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
; i
++)
432 if (SYMBOL_VALUE_ADDRESS (msymbol
+ i
) != SYMBOL_VALUE_ADDRESS (msymbol
)
433 && SYMBOL_BFD_SECTION (msymbol
+ i
) == SYMBOL_BFD_SECTION (msymbol
))
437 if (DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
438 && SYMBOL_VALUE_ADDRESS (msymbol
+ i
) < osect
->endaddr
)
439 cache_pc_function_high
= SYMBOL_VALUE_ADDRESS (msymbol
+ i
);
441 /* We got the start address from the last msymbol in the objfile.
442 So the end address is the end of the section. */
443 cache_pc_function_high
= osect
->endaddr
;
449 if (pc_in_unmapped_range (pc
, section
))
450 *address
= overlay_unmapped_address (cache_pc_function_low
, section
);
452 *address
= cache_pc_function_low
;
456 *name
= cache_pc_function_name
;
460 if (pc_in_unmapped_range (pc
, section
))
462 /* Because the high address is actually beyond the end of
463 the function (and therefore possibly beyond the end of
464 the overlay), we must actually convert (high - 1) and
465 then add one to that. */
467 *endaddr
= 1 + overlay_unmapped_address (cache_pc_function_high
- 1,
471 *endaddr
= cache_pc_function_high
;
477 /* Backward compatibility, no section argument. */
480 find_pc_partial_function (CORE_ADDR pc
, char **name
, CORE_ADDR
*address
,
485 section
= find_pc_overlay (pc
);
486 return find_pc_sect_partial_function (pc
, section
, name
, address
, endaddr
);
489 /* Return the innermost stack frame executing inside of BLOCK,
490 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
493 block_innermost_frame (struct block
*block
)
495 struct frame_info
*frame
;
496 register CORE_ADDR start
;
497 register CORE_ADDR end
;
498 CORE_ADDR calling_pc
;
503 start
= BLOCK_START (block
);
504 end
= BLOCK_END (block
);
509 frame
= get_prev_frame (frame
);
512 calling_pc
= frame_address_in_block (frame
);
513 if (calling_pc
>= start
&& calling_pc
< end
)
518 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
519 below is for infrun.c, which may give the macro a pc without that
522 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
523 top of the stack frame which we are checking, where "bottom" and
524 "top" refer to some section of memory which contains the code for
525 the call dummy. Calls to this macro assume that the contents of
526 SP_REGNUM and DEPRECATED_FP_REGNUM (or the saved values thereof),
527 respectively, are the things to pass.
529 This won't work on the 29k, where SP_REGNUM and
530 DEPRECATED_FP_REGNUM don't have that meaning, but the 29k doesn't
531 use ON_STACK. This could be fixed by generalizing this scheme,
532 perhaps by passing in a frame and adding a few fields, at least on
533 machines which need them for DEPRECATED_PC_IN_CALL_DUMMY.
535 Something simpler, like checking for the stack segment, doesn't work,
536 since various programs (threads implementations, gcc nested function
537 stubs, etc) may either allocate stack frames in another segment, or
538 allocate other kinds of code on the stack. */
541 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc
, CORE_ADDR sp
,
542 CORE_ADDR frame_address
)
544 return (INNER_THAN ((sp
), (pc
))
545 && (frame_address
!= 0)
546 && INNER_THAN ((pc
), (frame_address
)));
550 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc
, CORE_ADDR sp
,
551 CORE_ADDR frame_address
)
553 return ((pc
) >= CALL_DUMMY_ADDRESS ()
554 && (pc
) <= (CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK
));
557 /* Returns true for a user frame or a call_function_by_hand dummy
558 frame, and false for the CRT0 start-up frame. Purpose is to
559 terminate backtrace. */
562 legacy_frame_chain_valid (CORE_ADDR fp
, struct frame_info
*fi
)
564 /* Don't prune CALL_DUMMY frames. */
565 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
566 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi
), 0, 0))
569 /* If the new frame pointer is zero, then it isn't valid. */
573 /* If the new frame would be inside (younger than) the previous frame,
574 then it isn't valid. */
575 if (INNER_THAN (fp
, get_frame_base (fi
)))
578 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
580 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
581 return DEPRECATED_FRAME_CHAIN_VALID (fp
, fi
);
583 /* If we're already inside the entry function for the main objfile, then it
585 if (inside_entry_func (get_frame_pc (fi
)))
588 /* If we're inside the entry file, it isn't valid. */
589 /* NOTE/drow 2002-12-25: should there be a way to disable this check? It
590 assumes a single small entry file, and the way some debug readers (e.g.
591 dbxread) figure out which object is the entry file is somewhat hokey. */
592 if (inside_entry_file (frame_pc_unwind (fi
)))