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. */
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 deprecated_inside_entry_file (CORE_ADDR addr)
60 if (symfile_objfile == 0)
62 if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT
63 || CALL_DUMMY_LOCATION == AT_SYMBOL)
65 /* Do not stop backtracing if the pc is in the call dummy
66 at the entry point. */
67 /* FIXME: Won't always work with zeros for the last two arguments */
68 if (DEPRECATED_PC_IN_CALL_DUMMY (addr, 0, 0))
71 return (addr >= symfile_objfile->ei.deprecated_entry_file_lowpc &&
72 addr < symfile_objfile->ei.deprecated_entry_file_highpc);
75 /* Test whether PC is in the range of addresses that corresponds to
76 the "main" function. */
79 inside_main_func (CORE_ADDR pc)
81 struct minimal_symbol *msymbol;
83 if (symfile_objfile == 0)
86 msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
88 /* If the address range hasn't been set up at symbol reading time,
92 && symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC
93 && symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
95 /* brobecker/2003-10-10: We used to rely on lookup_symbol() to
96 search the symbol associated to the "main" function.
97 Unfortunately, lookup_symbol() uses the current-language
98 la_lookup_symbol_nonlocal function to do the global symbol
99 search. Depending on the language, this can introduce
100 certain side-effects, because certain languages, for instance
101 Ada, may find more than one match. Therefore we prefer to
102 search the "main" function symbol using its address rather
104 struct symbol *mainsym =
105 find_pc_function (SYMBOL_VALUE_ADDRESS (msymbol));
107 if (mainsym && SYMBOL_CLASS (mainsym) == LOC_BLOCK)
109 symfile_objfile->ei.main_func_lowpc =
110 BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
111 symfile_objfile->ei.main_func_highpc =
112 BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
116 /* Not in the normal symbol tables, see if "main" is in the partial
117 symbol table. If it's not, then give up. */
118 if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_text)
120 CORE_ADDR maddr = SYMBOL_VALUE_ADDRESS (msymbol);
121 asection *msect = SYMBOL_BFD_SECTION (msymbol);
122 struct obj_section *osect = find_pc_sect_section (maddr, msect);
128 /* Step over other symbols at this same address, and symbols
129 in other sections, to find the next symbol in this
130 section with a different address. */
131 for (i = 1; SYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++)
133 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != maddr
134 && SYMBOL_BFD_SECTION (msymbol + i) == msect)
138 symfile_objfile->ei.main_func_lowpc = maddr;
140 /* Use the lesser of the next minimal symbol in the same
141 section, or the end of the section, as the end of the
143 if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL
144 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
145 symfile_objfile->ei.main_func_highpc =
146 SYMBOL_VALUE_ADDRESS (msymbol + i);
148 /* We got the start address from the last msymbol in the
149 objfile. So the end address is the end of the
151 symfile_objfile->ei.main_func_highpc = osect->endaddr;
155 return (symfile_objfile->ei.main_func_lowpc <= pc
156 && symfile_objfile->ei.main_func_highpc > pc);
159 /* Test whether THIS_FRAME is inside the process entry point function. */
162 inside_entry_func (struct frame_info *this_frame)
164 return (get_frame_func (this_frame) == entry_point_address ());
167 /* Similar to inside_entry_func, but accomodating legacy frame code. */
170 legacy_inside_entry_func (CORE_ADDR pc)
172 if (symfile_objfile == 0)
175 if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
177 /* Do not stop backtracing if the program counter is in the call
178 dummy at the entry point. */
179 /* FIXME: This won't always work with zeros for the last two
181 if (DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0))
185 return (symfile_objfile->ei.entry_func_lowpc <= pc
186 && symfile_objfile->ei.entry_func_highpc > pc);
189 /* Return nonzero if the function for this frame lacks a prologue. Many
190 machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
194 frameless_look_for_prologue (struct frame_info *frame)
196 CORE_ADDR func_start;
198 func_start = get_frame_func (frame);
201 func_start += FUNCTION_START_OFFSET;
202 /* NOTE: cagney/2004-02-09: Eliminated per-architecture
203 PROLOGUE_FRAMELESS_P call as architectures with custom
204 implementations had all been deleted. Eventually even this
205 function can go - GDB no longer tries to differentiate
206 between framed, frameless and stackless functions. They are
207 all now considered equally evil :-^. */
208 /* If skipping the prologue ends up skips nothing, there must be
209 no prologue and hence no code creating a frame. There for
210 the function is "frameless" :-/. */
211 return func_start == SKIP_PROLOGUE (func_start);
213 else if (get_frame_pc (frame) == 0)
214 /* A frame with a zero PC is usually created by dereferencing a
215 NULL function pointer, normally causing an immediate core dump
216 of the inferior. Mark function as frameless, as the inferior
217 has no chance of setting up a stack frame. */
220 /* If we can't find the start of the function, we don't really
221 know whether the function is frameless, but we should be able
222 to get a reasonable (i.e. best we can do under the
223 circumstances) backtrace by saying that it isn't. */
227 /* Return the innermost lexical block in execution
228 in a specified stack frame. The frame address is assumed valid.
230 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
231 address we used to choose the block. We use this to find a source
232 line, to decide which macro definitions are in scope.
234 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
235 PC, and may not really be a valid PC at all. For example, in the
236 caller of a function declared to never return, the code at the
237 return address will never be reached, so the call instruction may
238 be the very last instruction in the block. So the address we use
239 to choose the block is actually one byte before the return address
240 --- hopefully pointing us at the call instruction, or its delay
244 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
246 const CORE_ADDR pc = get_frame_address_in_block (frame);
251 return block_for_pc (pc);
255 get_pc_function_start (CORE_ADDR pc)
258 struct minimal_symbol *msymbol;
260 bl = block_for_pc (pc);
263 struct symbol *symbol = block_function (bl);
267 bl = SYMBOL_BLOCK_VALUE (symbol);
268 return BLOCK_START (bl);
272 msymbol = lookup_minimal_symbol_by_pc (pc);
275 CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);
277 if (find_pc_section (fstart))
284 /* Return the symbol for the function executing in frame FRAME. */
287 get_frame_function (struct frame_info *frame)
289 struct block *bl = get_frame_block (frame, 0);
292 return block_function (bl);
296 /* Return the function containing pc value PC in section SECTION.
297 Returns 0 if function is not known. */
300 find_pc_sect_function (CORE_ADDR pc, struct bfd_section *section)
302 struct block *b = block_for_pc_sect (pc, section);
305 return block_function (b);
308 /* Return the function containing pc value PC.
309 Returns 0 if function is not known. Backward compatibility, no section */
312 find_pc_function (CORE_ADDR pc)
314 return find_pc_sect_function (pc, find_pc_mapped_section (pc));
317 /* These variables are used to cache the most recent result
318 * of find_pc_partial_function. */
320 static CORE_ADDR cache_pc_function_low = 0;
321 static CORE_ADDR cache_pc_function_high = 0;
322 static char *cache_pc_function_name = 0;
323 static struct bfd_section *cache_pc_function_section = NULL;
325 /* Clear cache, e.g. when symbol table is discarded. */
328 clear_pc_function_cache (void)
330 cache_pc_function_low = 0;
331 cache_pc_function_high = 0;
332 cache_pc_function_name = (char *) 0;
333 cache_pc_function_section = NULL;
336 /* Finds the "function" (text symbol) that is smaller than PC but
337 greatest of all of the potential text symbols in SECTION. Sets
338 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
339 If ENDADDR is non-null, then set *ENDADDR to be the end of the
340 function (exclusive), but passing ENDADDR as non-null means that
341 the function might cause symbols to be read. This function either
342 succeeds or fails (not halfway succeeds). If it succeeds, it sets
343 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
344 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
348 find_pc_sect_partial_function (CORE_ADDR pc, asection *section, char **name,
349 CORE_ADDR *address, CORE_ADDR *endaddr)
351 struct partial_symtab *pst;
353 struct minimal_symbol *msymbol;
354 struct partial_symbol *psb;
355 struct obj_section *osect;
359 mapped_pc = overlay_mapped_address (pc, section);
361 if (mapped_pc >= cache_pc_function_low
362 && mapped_pc < cache_pc_function_high
363 && section == cache_pc_function_section)
364 goto return_cached_value;
366 /* If sigtramp is in the u area, it counts as a function (especially
367 important for step_1). */
368 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL))
370 cache_pc_function_low = SIGTRAMP_START (mapped_pc);
371 cache_pc_function_high = SIGTRAMP_END (mapped_pc);
372 cache_pc_function_name = "<sigtramp>";
373 cache_pc_function_section = section;
374 goto return_cached_value;
377 msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
378 pst = find_pc_sect_psymtab (mapped_pc, section);
381 /* Need to read the symbols to get a good value for the end address. */
382 if (endaddr != NULL && !pst->readin)
384 /* Need to get the terminal in case symbol-reading produces
386 target_terminal_ours_for_output ();
387 PSYMTAB_TO_SYMTAB (pst);
392 /* Checking whether the msymbol has a larger value is for the
393 "pathological" case mentioned in print_frame_info. */
394 f = find_pc_sect_function (mapped_pc, section);
397 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
398 >= SYMBOL_VALUE_ADDRESS (msymbol))))
400 cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
401 cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
402 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (f);
403 cache_pc_function_section = section;
404 goto return_cached_value;
409 /* Now that static symbols go in the minimal symbol table, perhaps
410 we could just ignore the partial symbols. But at least for now
411 we use the partial or minimal symbol, whichever is larger. */
412 psb = find_pc_sect_psymbol (pst, mapped_pc, section);
415 && (msymbol == NULL ||
416 (SYMBOL_VALUE_ADDRESS (psb)
417 >= SYMBOL_VALUE_ADDRESS (msymbol))))
419 /* This case isn't being cached currently. */
421 *address = SYMBOL_VALUE_ADDRESS (psb);
423 *name = DEPRECATED_SYMBOL_NAME (psb);
424 /* endaddr non-NULL can't happen here. */
430 /* Not in the normal symbol tables, see if the pc is in a known section.
431 If it's not, then give up. This ensures that anything beyond the end
432 of the text seg doesn't appear to be part of the last function in the
435 osect = find_pc_sect_section (mapped_pc, section);
440 /* Must be in the minimal symbol table. */
443 /* No available symbol. */
453 cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
454 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (msymbol);
455 cache_pc_function_section = section;
457 /* Use the lesser of the next minimal symbol in the same section, or
458 the end of the section, as the end of the function. */
460 /* Step over other symbols at this same address, and symbols in
461 other sections, to find the next symbol in this section with
462 a different address. */
464 for (i = 1; DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL; i++)
466 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
467 && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
471 if (DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL
472 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
473 cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
475 /* We got the start address from the last msymbol in the objfile.
476 So the end address is the end of the section. */
477 cache_pc_function_high = osect->endaddr;
483 if (pc_in_unmapped_range (pc, section))
484 *address = overlay_unmapped_address (cache_pc_function_low, section);
486 *address = cache_pc_function_low;
490 *name = cache_pc_function_name;
494 if (pc_in_unmapped_range (pc, section))
496 /* Because the high address is actually beyond the end of
497 the function (and therefore possibly beyond the end of
498 the overlay), we must actually convert (high - 1) and
499 then add one to that. */
501 *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
505 *endaddr = cache_pc_function_high;
511 /* Backward compatibility, no section argument. */
514 find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
517 struct bfd_section *bfd_section;
519 /* To ensure that the symbol returned belongs to the correct setion
520 (and that the last [random] symbol from the previous section
521 isn't returned) try to find the section containing PC. First try
522 the overlay code (which by default returns NULL); and second try
523 the normal section code (which almost always succeeds). */
524 bfd_section = find_pc_overlay (pc);
525 if (bfd_section == NULL)
527 struct obj_section *obj_section = find_pc_section (pc);
528 if (obj_section == NULL)
531 bfd_section = obj_section->the_bfd_section;
533 return find_pc_sect_partial_function (pc, bfd_section, name, address,
537 /* Return the innermost stack frame executing inside of BLOCK,
538 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
541 block_innermost_frame (struct block *block)
543 struct frame_info *frame;
546 CORE_ADDR calling_pc;
551 start = BLOCK_START (block);
552 end = BLOCK_END (block);
557 frame = get_prev_frame (frame);
560 calling_pc = get_frame_address_in_block (frame);
561 if (calling_pc >= start && calling_pc < end)
566 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
567 below is for infrun.c, which may give the macro a pc without that
570 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
571 top of the stack frame which we are checking, where "bottom" and
572 "top" refer to some section of memory which contains the code for
573 the call dummy. Calls to this macro assume that the contents of
574 SP_REGNUM and DEPRECATED_FP_REGNUM (or the saved values thereof),
575 respectively, are the things to pass.
577 This won't work on the 29k, where SP_REGNUM and
578 DEPRECATED_FP_REGNUM don't have that meaning, but the 29k doesn't
579 use ON_STACK. This could be fixed by generalizing this scheme,
580 perhaps by passing in a frame and adding a few fields, at least on
581 machines which need them for DEPRECATED_PC_IN_CALL_DUMMY.
583 Something simpler, like checking for the stack segment, doesn't work,
584 since various programs (threads implementations, gcc nested function
585 stubs, etc) may either allocate stack frames in another segment, or
586 allocate other kinds of code on the stack. */
589 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp,
590 CORE_ADDR frame_address)
592 return (INNER_THAN ((sp), (pc))
593 && (frame_address != 0)
594 && INNER_THAN ((pc), (frame_address)));
598 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp,
599 CORE_ADDR frame_address)
601 CORE_ADDR addr = entry_point_address ();
602 if (DEPRECATED_CALL_DUMMY_ADDRESS_P ())
603 addr = DEPRECATED_CALL_DUMMY_ADDRESS ();
604 return ((pc) >= addr && (pc) <= (addr + DECR_PC_AFTER_BREAK));
607 /* Returns true for a user frame or a call_function_by_hand dummy
608 frame, and false for the CRT0 start-up frame. Purpose is to
609 terminate backtrace. */
612 legacy_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
614 /* Don't prune CALL_DUMMY frames. */
615 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
616 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
619 /* If the new frame pointer is zero, then it isn't valid. */
623 /* If the new frame would be inside (younger than) the previous frame,
624 then it isn't valid. */
625 if (INNER_THAN (fp, get_frame_base (fi)))
628 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
630 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
631 return DEPRECATED_FRAME_CHAIN_VALID (fp, fi);
633 /* If we're already inside the entry function for the main objfile, then it
635 if (legacy_inside_entry_func (get_frame_pc (fi)))
638 /* If we're inside the entry file, it isn't valid. */
639 /* NOTE/drow 2002-12-25: should there be a way to disable this check? It
640 assumes a single small entry file, and the way some debug readers (e.g.
641 dbxread) figure out which object is the entry file is somewhat hokey. */
642 if (deprecated_inside_entry_file (frame_pc_unwind (fi)))