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_DOMAIN, 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));
110 /* Not in the normal symbol tables, see if "main" is in the partial
111 symbol table. If it's not, then give up. */
113 struct minimal_symbol *msymbol
114 = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
115 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_text)
117 struct obj_section *osect
118 = find_pc_sect_section (SYMBOL_VALUE_ADDRESS (msymbol),
119 msymbol->ginfo.bfd_section);
123 /* Step over other symbols at this same address, and
124 symbols in other sections, to find the next symbol in
125 this section with a different address. */
126 for (i = 1; SYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
128 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
129 && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
133 symfile_objfile->ei.main_func_lowpc = SYMBOL_VALUE_ADDRESS (msymbol);
135 /* Use the lesser of the next minimal symbol in the same
136 section, or the end of the section, as the end of the
138 if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL
139 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
140 symfile_objfile->ei.main_func_highpc = SYMBOL_VALUE_ADDRESS (msymbol + i);
142 /* We got the start address from the last msymbol in the
143 objfile. So the end address is the end of the
145 symfile_objfile->ei.main_func_highpc = osect->endaddr;
150 return (symfile_objfile->ei.main_func_lowpc <= pc &&
151 symfile_objfile->ei.main_func_highpc > pc);
154 /* Test a specified PC value to see if it is in the range of addresses
155 that correspond to the process entry point function. See comments
156 in objfiles.h for why we might want to do this.
158 Typically called from DEPRECATED_FRAME_CHAIN_VALID.
160 A PC of zero is always considered to be the bottom of the stack. */
163 inside_entry_func (CORE_ADDR pc)
167 if (symfile_objfile == 0)
169 if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
171 /* Do not stop backtracing if the pc is in the call dummy
172 at the entry point. */
173 /* FIXME: Won't always work with zeros for the last two arguments */
174 if (DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0))
177 return (symfile_objfile->ei.entry_func_lowpc <= pc &&
178 symfile_objfile->ei.entry_func_highpc > pc);
181 /* Return nonzero if the function for this frame lacks a prologue. Many
182 machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
186 frameless_look_for_prologue (struct frame_info *frame)
188 CORE_ADDR func_start;
190 func_start = get_frame_func (frame);
193 func_start += FUNCTION_START_OFFSET;
194 /* This is faster, since only care whether there *is* a
195 prologue, not how long it is. */
196 return PROLOGUE_FRAMELESS_P (func_start);
198 else if (get_frame_pc (frame) == 0)
199 /* A frame with a zero PC is usually created by dereferencing a
200 NULL function pointer, normally causing an immediate core dump
201 of the inferior. Mark function as frameless, as the inferior
202 has no chance of setting up a stack frame. */
205 /* If we can't find the start of the function, we don't really
206 know whether the function is frameless, but we should be able
207 to get a reasonable (i.e. best we can do under the
208 circumstances) backtrace by saying that it isn't. */
212 /* Return the innermost lexical block in execution
213 in a specified stack frame. The frame address is assumed valid.
215 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
216 address we used to choose the block. We use this to find a source
217 line, to decide which macro definitions are in scope.
219 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
220 PC, and may not really be a valid PC at all. For example, in the
221 caller of a function declared to never return, the code at the
222 return address will never be reached, so the call instruction may
223 be the very last instruction in the block. So the address we use
224 to choose the block is actually one byte before the return address
225 --- hopefully pointing us at the call instruction, or its delay
229 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
231 const CORE_ADDR pc = get_frame_address_in_block (frame);
236 return block_for_pc (pc);
240 get_pc_function_start (CORE_ADDR pc)
243 struct minimal_symbol *msymbol;
245 bl = block_for_pc (pc);
248 struct symbol *symbol = block_function (bl);
252 bl = SYMBOL_BLOCK_VALUE (symbol);
253 return BLOCK_START (bl);
257 msymbol = lookup_minimal_symbol_by_pc (pc);
260 CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);
262 if (find_pc_section (fstart))
269 /* Return the symbol for the function executing in frame FRAME. */
272 get_frame_function (struct frame_info *frame)
274 register struct block *bl = get_frame_block (frame, 0);
277 return block_function (bl);
281 /* Return the function containing pc value PC in section SECTION.
282 Returns 0 if function is not known. */
285 find_pc_sect_function (CORE_ADDR pc, struct sec *section)
287 register struct block *b = block_for_pc_sect (pc, section);
290 return block_function (b);
293 /* Return the function containing pc value PC.
294 Returns 0 if function is not known. Backward compatibility, no section */
297 find_pc_function (CORE_ADDR pc)
299 return find_pc_sect_function (pc, find_pc_mapped_section (pc));
302 /* These variables are used to cache the most recent result
303 * of find_pc_partial_function. */
305 static CORE_ADDR cache_pc_function_low = 0;
306 static CORE_ADDR cache_pc_function_high = 0;
307 static char *cache_pc_function_name = 0;
308 static struct sec *cache_pc_function_section = NULL;
310 /* Clear cache, e.g. when symbol table is discarded. */
313 clear_pc_function_cache (void)
315 cache_pc_function_low = 0;
316 cache_pc_function_high = 0;
317 cache_pc_function_name = (char *) 0;
318 cache_pc_function_section = NULL;
321 /* Finds the "function" (text symbol) that is smaller than PC but
322 greatest of all of the potential text symbols in SECTION. Sets
323 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
324 If ENDADDR is non-null, then set *ENDADDR to be the end of the
325 function (exclusive), but passing ENDADDR as non-null means that
326 the function might cause symbols to be read. This function either
327 succeeds or fails (not halfway succeeds). If it succeeds, it sets
328 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
329 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
333 find_pc_sect_partial_function (CORE_ADDR pc, asection *section, char **name,
334 CORE_ADDR *address, CORE_ADDR *endaddr)
336 struct partial_symtab *pst;
338 struct minimal_symbol *msymbol;
339 struct partial_symbol *psb;
340 struct obj_section *osect;
344 mapped_pc = overlay_mapped_address (pc, section);
346 if (mapped_pc >= cache_pc_function_low
347 && mapped_pc < cache_pc_function_high
348 && section == cache_pc_function_section)
349 goto return_cached_value;
351 /* If sigtramp is in the u area, it counts as a function (especially
352 important for step_1). */
353 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL))
355 cache_pc_function_low = SIGTRAMP_START (mapped_pc);
356 cache_pc_function_high = SIGTRAMP_END (mapped_pc);
357 cache_pc_function_name = "<sigtramp>";
358 cache_pc_function_section = section;
359 goto return_cached_value;
362 msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
363 pst = find_pc_sect_psymtab (mapped_pc, section);
366 /* Need to read the symbols to get a good value for the end address. */
367 if (endaddr != NULL && !pst->readin)
369 /* Need to get the terminal in case symbol-reading produces
371 target_terminal_ours_for_output ();
372 PSYMTAB_TO_SYMTAB (pst);
377 /* Checking whether the msymbol has a larger value is for the
378 "pathological" case mentioned in print_frame_info. */
379 f = find_pc_sect_function (mapped_pc, section);
382 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
383 >= SYMBOL_VALUE_ADDRESS (msymbol))))
385 cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
386 cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
387 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (f);
388 cache_pc_function_section = section;
389 goto return_cached_value;
394 /* Now that static symbols go in the minimal symbol table, perhaps
395 we could just ignore the partial symbols. But at least for now
396 we use the partial or minimal symbol, whichever is larger. */
397 psb = find_pc_sect_psymbol (pst, mapped_pc, section);
400 && (msymbol == NULL ||
401 (SYMBOL_VALUE_ADDRESS (psb)
402 >= SYMBOL_VALUE_ADDRESS (msymbol))))
404 /* This case isn't being cached currently. */
406 *address = SYMBOL_VALUE_ADDRESS (psb);
408 *name = DEPRECATED_SYMBOL_NAME (psb);
409 /* endaddr non-NULL can't happen here. */
415 /* Not in the normal symbol tables, see if the pc is in a known section.
416 If it's not, then give up. This ensures that anything beyond the end
417 of the text seg doesn't appear to be part of the last function in the
420 osect = find_pc_sect_section (mapped_pc, section);
425 /* Must be in the minimal symbol table. */
428 /* No available symbol. */
438 cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
439 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (msymbol);
440 cache_pc_function_section = section;
442 /* Use the lesser of the next minimal symbol in the same section, or
443 the end of the section, as the end of the function. */
445 /* Step over other symbols at this same address, and symbols in
446 other sections, to find the next symbol in this section with
447 a different address. */
449 for (i = 1; DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL; i++)
451 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
452 && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
456 if (DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL
457 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
458 cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
460 /* We got the start address from the last msymbol in the objfile.
461 So the end address is the end of the section. */
462 cache_pc_function_high = osect->endaddr;
468 if (pc_in_unmapped_range (pc, section))
469 *address = overlay_unmapped_address (cache_pc_function_low, section);
471 *address = cache_pc_function_low;
475 *name = cache_pc_function_name;
479 if (pc_in_unmapped_range (pc, section))
481 /* Because the high address is actually beyond the end of
482 the function (and therefore possibly beyond the end of
483 the overlay), we must actually convert (high - 1) and
484 then add one to that. */
486 *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
490 *endaddr = cache_pc_function_high;
496 /* Backward compatibility, no section argument. */
499 find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
504 section = find_pc_overlay (pc);
505 return find_pc_sect_partial_function (pc, section, name, address, endaddr);
508 /* Return the innermost stack frame executing inside of BLOCK,
509 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
512 block_innermost_frame (struct block *block)
514 struct frame_info *frame;
515 register CORE_ADDR start;
516 register CORE_ADDR end;
517 CORE_ADDR calling_pc;
522 start = BLOCK_START (block);
523 end = BLOCK_END (block);
528 frame = get_prev_frame (frame);
531 calling_pc = get_frame_address_in_block (frame);
532 if (calling_pc >= start && calling_pc < end)
537 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
538 below is for infrun.c, which may give the macro a pc without that
541 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
542 top of the stack frame which we are checking, where "bottom" and
543 "top" refer to some section of memory which contains the code for
544 the call dummy. Calls to this macro assume that the contents of
545 SP_REGNUM and DEPRECATED_FP_REGNUM (or the saved values thereof),
546 respectively, are the things to pass.
548 This won't work on the 29k, where SP_REGNUM and
549 DEPRECATED_FP_REGNUM don't have that meaning, but the 29k doesn't
550 use ON_STACK. This could be fixed by generalizing this scheme,
551 perhaps by passing in a frame and adding a few fields, at least on
552 machines which need them for DEPRECATED_PC_IN_CALL_DUMMY.
554 Something simpler, like checking for the stack segment, doesn't work,
555 since various programs (threads implementations, gcc nested function
556 stubs, etc) may either allocate stack frames in another segment, or
557 allocate other kinds of code on the stack. */
560 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp,
561 CORE_ADDR frame_address)
563 return (INNER_THAN ((sp), (pc))
564 && (frame_address != 0)
565 && INNER_THAN ((pc), (frame_address)));
569 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp,
570 CORE_ADDR frame_address)
572 return ((pc) >= CALL_DUMMY_ADDRESS ()
573 && (pc) <= (CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK));
576 /* Returns true for a user frame or a call_function_by_hand dummy
577 frame, and false for the CRT0 start-up frame. Purpose is to
578 terminate backtrace. */
581 legacy_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
583 /* Don't prune CALL_DUMMY frames. */
584 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
585 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
588 /* If the new frame pointer is zero, then it isn't valid. */
592 /* If the new frame would be inside (younger than) the previous frame,
593 then it isn't valid. */
594 if (INNER_THAN (fp, get_frame_base (fi)))
597 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
599 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
600 return DEPRECATED_FRAME_CHAIN_VALID (fp, fi);
602 /* If we're already inside the entry function for the main objfile, then it
604 if (inside_entry_func (get_frame_pc (fi)))
607 /* If we're inside the entry file, it isn't valid. */
608 /* NOTE/drow 2002-12-25: should there be a way to disable this check? It
609 assumes a single small entry file, and the way some debug readers (e.g.
610 dbxread) figure out which object is the entry file is somewhat hokey. */
611 if (inside_entry_file (frame_pc_unwind (fi)))