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, 2004
6 Free Software Foundation, Inc.
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. */
31 #include "value.h" /* for read_register */
32 #include "target.h" /* for target_has_stack */
33 #include "inferior.h" /* for read_pc */
36 #include "gdb_assert.h"
37 #include "dummy-frame.h"
42 /* Prototypes for exported functions. */
44 void _initialize_blockframe (void);
46 /* Is ADDR inside the startup file? Note that if your machine has a
47 way to detect the bottom of the stack, there is no need to call
48 this function from DEPRECATED_FRAME_CHAIN_VALID; the reason for
49 doing so is that some machines have no way of detecting bottom of
52 A PC of zero is always considered to be the bottom of the stack. */
55 deprecated_inside_entry_file (CORE_ADDR addr)
59 if (symfile_objfile == 0)
61 if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT
62 || CALL_DUMMY_LOCATION == AT_SYMBOL)
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.deprecated_entry_file_lowpc &&
71 addr < symfile_objfile->ei.deprecated_entry_file_highpc);
74 /* Test whether PC is in the range of addresses that corresponds to
75 the "main" function. */
78 inside_main_func (CORE_ADDR pc)
80 struct minimal_symbol *msymbol;
82 if (symfile_objfile == 0)
85 msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
87 /* If the address range hasn't been set up at symbol reading time,
91 && symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC
92 && symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
94 /* brobecker/2003-10-10: We used to rely on lookup_symbol() to
95 search the symbol associated to the "main" function.
96 Unfortunately, lookup_symbol() uses the current-language
97 la_lookup_symbol_nonlocal function to do the global symbol
98 search. Depending on the language, this can introduce
99 certain side-effects, because certain languages, for instance
100 Ada, may find more than one match. Therefore we prefer to
101 search the "main" function symbol using its address rather
103 struct symbol *mainsym =
104 find_pc_function (SYMBOL_VALUE_ADDRESS (msymbol));
106 if (mainsym && SYMBOL_CLASS (mainsym) == LOC_BLOCK)
108 symfile_objfile->ei.main_func_lowpc =
109 BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
110 symfile_objfile->ei.main_func_highpc =
111 BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
115 /* Not in the normal symbol tables, see if "main" is in the partial
116 symbol table. If it's not, then give up. */
117 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_text)
119 CORE_ADDR maddr = SYMBOL_VALUE_ADDRESS (msymbol);
120 asection *msect = SYMBOL_BFD_SECTION (msymbol);
121 struct obj_section *osect = find_pc_sect_section (maddr, msect);
127 /* Step over other symbols at this same address, and symbols
128 in other sections, to find the next symbol in this
129 section with a different address. */
130 for (i = 1; SYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
132 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != maddr
133 && SYMBOL_BFD_SECTION (msymbol + i) == msect)
137 symfile_objfile->ei.main_func_lowpc = maddr;
139 /* Use the lesser of the next minimal symbol in the same
140 section, or the end of the section, as the end of the
142 if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL
143 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
144 symfile_objfile->ei.main_func_highpc =
145 SYMBOL_VALUE_ADDRESS (msymbol + i);
147 /* We got the start address from the last msymbol in the
148 objfile. So the end address is the end of the
150 symfile_objfile->ei.main_func_highpc = osect->endaddr;
154 return (symfile_objfile->ei.main_func_lowpc <= pc
155 && symfile_objfile->ei.main_func_highpc > pc);
158 /* Test whether THIS_FRAME is inside the process entry point function. */
161 inside_entry_func (struct frame_info *this_frame)
163 return (get_frame_func (this_frame) == entry_point_address ());
166 /* Similar to inside_entry_func, but accomodating legacy frame code. */
169 legacy_inside_entry_func (CORE_ADDR pc)
171 if (symfile_objfile == 0)
174 if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
176 /* Do not stop backtracing if the program counter is in the call
177 dummy at the entry point. */
178 /* FIXME: This won't always work with zeros for the last two
180 if (DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0))
184 return (symfile_objfile->ei.entry_func_lowpc <= pc
185 && symfile_objfile->ei.entry_func_highpc > pc);
188 /* Return nonzero if the function for this frame lacks a prologue. Many
189 machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
193 frameless_look_for_prologue (struct frame_info *frame)
195 CORE_ADDR func_start;
197 func_start = get_frame_func (frame);
200 func_start += FUNCTION_START_OFFSET;
201 /* NOTE: cagney/2004-02-09: Eliminated per-architecture
202 PROLOGUE_FRAMELESS_P call as architectures with custom
203 implementations had all been deleted. Eventually even this
204 function can go - GDB no longer tries to differentiate
205 between framed, frameless and stackless functions. They are
206 all now considered equally evil :-^. */
207 /* If skipping the prologue ends up skips nothing, there must be
208 no prologue and hence no code creating a frame. There for
209 the function is "frameless" :-/. */
210 return func_start == SKIP_PROLOGUE (func_start);
212 else if (get_frame_pc (frame) == 0)
213 /* A frame with a zero PC is usually created by dereferencing a
214 NULL function pointer, normally causing an immediate core dump
215 of the inferior. Mark function as frameless, as the inferior
216 has no chance of setting up a stack frame. */
219 /* If we can't find the start of the function, we don't really
220 know whether the function is frameless, but we should be able
221 to get a reasonable (i.e. best we can do under the
222 circumstances) backtrace by saying that it isn't. */
226 /* Return the innermost lexical block in execution
227 in a specified stack frame. The frame address is assumed valid.
229 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
230 address we used to choose the block. We use this to find a source
231 line, to decide which macro definitions are in scope.
233 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
234 PC, and may not really be a valid PC at all. For example, in the
235 caller of a function declared to never return, the code at the
236 return address will never be reached, so the call instruction may
237 be the very last instruction in the block. So the address we use
238 to choose the block is actually one byte before the return address
239 --- hopefully pointing us at the call instruction, or its delay
243 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
245 const CORE_ADDR pc = get_frame_address_in_block (frame);
250 return block_for_pc (pc);
254 get_pc_function_start (CORE_ADDR pc)
257 struct minimal_symbol *msymbol;
259 bl = block_for_pc (pc);
262 struct symbol *symbol = block_function (bl);
266 bl = SYMBOL_BLOCK_VALUE (symbol);
267 return BLOCK_START (bl);
271 msymbol = lookup_minimal_symbol_by_pc (pc);
274 CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);
276 if (find_pc_section (fstart))
283 /* Return the symbol for the function executing in frame FRAME. */
286 get_frame_function (struct frame_info *frame)
288 struct block *bl = get_frame_block (frame, 0);
291 return block_function (bl);
295 /* Return the function containing pc value PC in section SECTION.
296 Returns 0 if function is not known. */
299 find_pc_sect_function (CORE_ADDR pc, struct bfd_section *section)
301 struct block *b = block_for_pc_sect (pc, section);
304 return block_function (b);
307 /* Return the function containing pc value PC.
308 Returns 0 if function is not known. Backward compatibility, no section */
311 find_pc_function (CORE_ADDR pc)
313 return find_pc_sect_function (pc, find_pc_mapped_section (pc));
316 /* These variables are used to cache the most recent result
317 * of find_pc_partial_function. */
319 static CORE_ADDR cache_pc_function_low = 0;
320 static CORE_ADDR cache_pc_function_high = 0;
321 static char *cache_pc_function_name = 0;
322 static struct bfd_section *cache_pc_function_section = NULL;
324 /* Clear cache, e.g. when symbol table is discarded. */
327 clear_pc_function_cache (void)
329 cache_pc_function_low = 0;
330 cache_pc_function_high = 0;
331 cache_pc_function_name = (char *) 0;
332 cache_pc_function_section = NULL;
335 /* Finds the "function" (text symbol) that is smaller than PC but
336 greatest of all of the potential text symbols in SECTION. Sets
337 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
338 If ENDADDR is non-null, then set *ENDADDR to be the end of the
339 function (exclusive), but passing ENDADDR as non-null means that
340 the function might cause symbols to be read. This function either
341 succeeds or fails (not halfway succeeds). If it succeeds, it sets
342 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
343 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
347 find_pc_sect_partial_function (CORE_ADDR pc, asection *section, char **name,
348 CORE_ADDR *address, CORE_ADDR *endaddr)
350 struct partial_symtab *pst;
352 struct minimal_symbol *msymbol;
353 struct partial_symbol *psb;
354 struct obj_section *osect;
358 mapped_pc = overlay_mapped_address (pc, section);
360 if (mapped_pc >= cache_pc_function_low
361 && mapped_pc < cache_pc_function_high
362 && section == cache_pc_function_section)
363 goto return_cached_value;
365 /* If sigtramp is in the u area, it counts as a function (especially
366 important for step_1). */
367 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL))
369 cache_pc_function_low = SIGTRAMP_START (mapped_pc);
370 cache_pc_function_high = SIGTRAMP_END (mapped_pc);
371 cache_pc_function_name = "<sigtramp>";
372 cache_pc_function_section = section;
373 goto return_cached_value;
376 msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
377 pst = find_pc_sect_psymtab (mapped_pc, section);
380 /* Need to read the symbols to get a good value for the end address. */
381 if (endaddr != NULL && !pst->readin)
383 /* Need to get the terminal in case symbol-reading produces
385 target_terminal_ours_for_output ();
386 PSYMTAB_TO_SYMTAB (pst);
391 /* Checking whether the msymbol has a larger value is for the
392 "pathological" case mentioned in print_frame_info. */
393 f = find_pc_sect_function (mapped_pc, section);
396 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
397 >= SYMBOL_VALUE_ADDRESS (msymbol))))
399 cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
400 cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
401 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (f);
402 cache_pc_function_section = section;
403 goto return_cached_value;
408 /* Now that static symbols go in the minimal symbol table, perhaps
409 we could just ignore the partial symbols. But at least for now
410 we use the partial or minimal symbol, whichever is larger. */
411 psb = find_pc_sect_psymbol (pst, mapped_pc, section);
414 && (msymbol == NULL ||
415 (SYMBOL_VALUE_ADDRESS (psb)
416 >= SYMBOL_VALUE_ADDRESS (msymbol))))
418 /* This case isn't being cached currently. */
420 *address = SYMBOL_VALUE_ADDRESS (psb);
422 *name = DEPRECATED_SYMBOL_NAME (psb);
423 /* endaddr non-NULL can't happen here. */
429 /* Not in the normal symbol tables, see if the pc is in a known section.
430 If it's not, then give up. This ensures that anything beyond the end
431 of the text seg doesn't appear to be part of the last function in the
434 osect = find_pc_sect_section (mapped_pc, section);
439 /* Must be in the minimal symbol table. */
442 /* No available symbol. */
452 cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
453 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (msymbol);
454 cache_pc_function_section = section;
456 /* Use the lesser of the next minimal symbol in the same section, or
457 the end of the section, as the end of the function. */
459 /* Step over other symbols at this same address, and symbols in
460 other sections, to find the next symbol in this section with
461 a different address. */
463 for (i = 1; DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL; i++)
465 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
466 && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
470 if (DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL
471 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
472 cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
474 /* We got the start address from the last msymbol in the objfile.
475 So the end address is the end of the section. */
476 cache_pc_function_high = osect->endaddr;
482 if (pc_in_unmapped_range (pc, section))
483 *address = overlay_unmapped_address (cache_pc_function_low, section);
485 *address = cache_pc_function_low;
489 *name = cache_pc_function_name;
493 if (pc_in_unmapped_range (pc, section))
495 /* Because the high address is actually beyond the end of
496 the function (and therefore possibly beyond the end of
497 the overlay), we must actually convert (high - 1) and
498 then add one to that. */
500 *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
504 *endaddr = cache_pc_function_high;
510 /* Backward compatibility, no section argument. */
513 find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
516 struct bfd_section *bfd_section;
518 /* To ensure that the symbol returned belongs to the correct setion
519 (and that the last [random] symbol from the previous section
520 isn't returned) try to find the section containing PC. First try
521 the overlay code (which by default returns NULL); and second try
522 the normal section code (which almost always succeeds). */
523 bfd_section = find_pc_overlay (pc);
524 if (bfd_section == NULL)
526 struct obj_section *obj_section = find_pc_section (pc);
527 if (obj_section == NULL)
530 bfd_section = obj_section->the_bfd_section;
532 return find_pc_sect_partial_function (pc, bfd_section, name, address,
536 /* Return the innermost stack frame executing inside of BLOCK,
537 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
540 block_innermost_frame (struct block *block)
542 struct frame_info *frame;
545 CORE_ADDR calling_pc;
550 start = BLOCK_START (block);
551 end = BLOCK_END (block);
556 frame = get_prev_frame (frame);
559 calling_pc = get_frame_address_in_block (frame);
560 if (calling_pc >= start && calling_pc < end)
565 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
566 below is for infrun.c, which may give the macro a pc without that
569 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
570 top of the stack frame which we are checking, where "bottom" and
571 "top" refer to some section of memory which contains the code for
572 the call dummy. Calls to this macro assume that the contents of
573 SP_REGNUM and DEPRECATED_FP_REGNUM (or the saved values thereof),
574 respectively, are the things to pass.
576 This won't work on the 29k, where SP_REGNUM and
577 DEPRECATED_FP_REGNUM don't have that meaning, but the 29k doesn't
578 use ON_STACK. This could be fixed by generalizing this scheme,
579 perhaps by passing in a frame and adding a few fields, at least on
580 machines which need them for DEPRECATED_PC_IN_CALL_DUMMY.
582 Something simpler, like checking for the stack segment, doesn't work,
583 since various programs (threads implementations, gcc nested function
584 stubs, etc) may either allocate stack frames in another segment, or
585 allocate other kinds of code on the stack. */
588 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp,
589 CORE_ADDR frame_address)
591 return (INNER_THAN ((sp), (pc))
592 && (frame_address != 0)
593 && INNER_THAN ((pc), (frame_address)));
597 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp,
598 CORE_ADDR frame_address)
600 CORE_ADDR addr = entry_point_address ();
601 return ((pc) >= addr && (pc) <= (addr + DECR_PC_AFTER_BREAK));
604 /* Returns true for a user frame or a call_function_by_hand dummy
605 frame, and false for the CRT0 start-up frame. Purpose is to
606 terminate backtrace. */
609 legacy_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
611 /* Don't prune CALL_DUMMY frames. */
612 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
613 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
616 /* If the new frame pointer is zero, then it isn't valid. */
620 /* If the new frame would be inside (younger than) the previous frame,
621 then it isn't valid. */
622 if (INNER_THAN (fp, get_frame_base (fi)))
625 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
627 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
628 return DEPRECATED_FRAME_CHAIN_VALID (fp, fi);
630 /* If we're already inside the entry function for the main objfile, then it
632 if (legacy_inside_entry_func (get_frame_pc (fi)))
635 /* If we're inside the entry file, it isn't valid. */
636 /* NOTE/drow 2002-12-25: should there be a way to disable this check? It
637 assumes a single small entry file, and the way some debug readers (e.g.
638 dbxread) figure out which object is the entry file is somewhat hokey. */
639 if (deprecated_inside_entry_file (frame_pc_unwind (fi)))