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 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"
40 /* Prototypes for exported functions. */
42 void _initialize_blockframe (void);
44 /* A default FRAME_CHAIN_VALID, in the form that is suitable for most
45 targets. If FRAME_CHAIN_VALID returns zero it means that the given
46 frame is the outermost one and has no caller. */
49 file_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
52 && !inside_entry_file (frame_pc_unwind (thisframe)));
55 /* Use the alternate method of avoiding running up off the end of the
56 frame chain or following frames back into the startup code. See
57 the comments in objfiles.h. */
60 func_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
63 && !inside_main_func (get_frame_pc (thisframe))
64 && !inside_entry_func (get_frame_pc (thisframe)));
67 /* A very simple method of determining a valid frame */
70 nonnull_frame_chain_valid (CORE_ADDR chain, struct frame_info *thisframe)
72 return ((chain) != 0);
75 /* Is ADDR inside the startup file? Note that if your machine
76 has a way to detect the bottom of the stack, there is no need
77 to call this function from FRAME_CHAIN_VALID; the reason for
78 doing so is that some machines have no way of detecting bottom
81 A PC of zero is always considered to be the bottom of the stack. */
84 inside_entry_file (CORE_ADDR addr)
88 if (symfile_objfile == 0)
90 if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
92 /* Do not stop backtracing if the pc is in the call dummy
93 at the entry point. */
94 /* FIXME: Won't always work with zeros for the last two arguments */
95 if (DEPRECATED_PC_IN_CALL_DUMMY (addr, 0, 0))
98 return (addr >= symfile_objfile->ei.entry_file_lowpc &&
99 addr < symfile_objfile->ei.entry_file_highpc);
102 /* Test a specified PC value to see if it is in the range of addresses
103 that correspond to the main() function. See comments above for why
104 we might want to do this.
106 Typically called from FRAME_CHAIN_VALID.
108 A PC of zero is always considered to be the bottom of the stack. */
111 inside_main_func (CORE_ADDR pc)
115 if (symfile_objfile == 0)
118 /* If the addr range is not set up at symbol reading time, set it up now.
119 This is for FRAME_CHAIN_VALID_ALTERNATE. I do this for coff, because
120 it is unable to set it up and symbol reading time. */
122 if (symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC &&
123 symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
125 struct symbol *mainsym;
127 mainsym = lookup_symbol (main_name (), NULL, VAR_NAMESPACE, NULL, NULL);
128 if (mainsym && SYMBOL_CLASS (mainsym) == LOC_BLOCK)
130 symfile_objfile->ei.main_func_lowpc =
131 BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym));
132 symfile_objfile->ei.main_func_highpc =
133 BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym));
136 return (symfile_objfile->ei.main_func_lowpc <= pc &&
137 symfile_objfile->ei.main_func_highpc > pc);
140 /* Test a specified PC value to see if it is in the range of addresses
141 that correspond to the process entry point function. See comments
142 in objfiles.h for why we might want to do this.
144 Typically called from FRAME_CHAIN_VALID.
146 A PC of zero is always considered to be the bottom of the stack. */
149 inside_entry_func (CORE_ADDR pc)
153 if (symfile_objfile == 0)
155 if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
157 /* Do not stop backtracing if the pc is in the call dummy
158 at the entry point. */
159 /* FIXME: Won't always work with zeros for the last two arguments */
160 if (DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0))
163 return (symfile_objfile->ei.entry_func_lowpc <= pc &&
164 symfile_objfile->ei.entry_func_highpc > pc);
167 /* Return nonzero if the function for this frame lacks a prologue. Many
168 machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
172 frameless_look_for_prologue (struct frame_info *frame)
174 CORE_ADDR func_start, after_prologue;
176 func_start = get_pc_function_start (get_frame_pc (frame));
179 func_start += FUNCTION_START_OFFSET;
180 /* This is faster, since only care whether there *is* a
181 prologue, not how long it is. */
182 return PROLOGUE_FRAMELESS_P (func_start);
184 else if (get_frame_pc (frame) == 0)
185 /* A frame with a zero PC is usually created by dereferencing a
186 NULL function pointer, normally causing an immediate core dump
187 of the inferior. Mark function as frameless, as the inferior
188 has no chance of setting up a stack frame. */
191 /* If we can't find the start of the function, we don't really
192 know whether the function is frameless, but we should be able
193 to get a reasonable (i.e. best we can do under the
194 circumstances) backtrace by saying that it isn't. */
198 /* return the address of the PC for the given FRAME, ie the current PC value
199 if FRAME is the innermost frame, or the address adjusted to point to the
200 call instruction if not. */
203 frame_address_in_block (struct frame_info *frame)
205 CORE_ADDR pc = get_frame_pc (frame);
207 /* If we are not in the innermost frame, and we are not interrupted
208 by a signal, frame->pc points to the instruction following the
209 call. As a consequence, we need to get the address of the previous
210 instruction. Unfortunately, this is not straightforward to do, so
211 we just use the address minus one, which is a good enough
213 /* FIXME: cagney/2002-11-10: Should this instead test for
214 NORMAL_FRAME? A dummy frame (in fact all the abnormal frames)
215 save the PC value in the block. */
216 if (get_next_frame (frame) != 0
217 && get_frame_type (get_next_frame (frame)) != SIGTRAMP_FRAME)
223 /* Return the innermost lexical block in execution
224 in a specified stack frame. The frame address is assumed valid.
226 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
227 address we used to choose the block. We use this to find a source
228 line, to decide which macro definitions are in scope.
230 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
231 PC, and may not really be a valid PC at all. For example, in the
232 caller of a function declared to never return, the code at the
233 return address will never be reached, so the call instruction may
234 be the very last instruction in the block. So the address we use
235 to choose the block is actually one byte before the return address
236 --- hopefully pointing us at the call instruction, or its delay
240 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
242 const CORE_ADDR pc = frame_address_in_block (frame);
247 return block_for_pc (pc);
251 get_pc_function_start (CORE_ADDR pc)
253 register struct block *bl;
254 register struct symbol *symbol;
255 register struct minimal_symbol *msymbol;
258 if ((bl = block_for_pc (pc)) != NULL &&
259 (symbol = block_function (bl)) != NULL)
261 bl = SYMBOL_BLOCK_VALUE (symbol);
262 fstart = BLOCK_START (bl);
264 else if ((msymbol = lookup_minimal_symbol_by_pc (pc)) != NULL)
266 fstart = SYMBOL_VALUE_ADDRESS (msymbol);
267 if (!find_pc_section (fstart))
277 /* Return the symbol for the function executing in frame FRAME. */
280 get_frame_function (struct frame_info *frame)
282 register struct block *bl = get_frame_block (frame, 0);
285 return block_function (bl);
289 /* Return the blockvector immediately containing the innermost lexical block
290 containing the specified pc value and section, or 0 if there is none.
291 PINDEX is a pointer to the index value of the block. If PINDEX
292 is NULL, we don't pass this information back to the caller. */
295 blockvector_for_pc_sect (register CORE_ADDR pc, struct sec *section,
296 int *pindex, struct symtab *symtab)
298 register struct block *b;
299 register int bot, top, half;
300 struct blockvector *bl;
302 if (symtab == 0) /* if no symtab specified by caller */
304 /* First search all symtabs for one whose file contains our pc */
305 if ((symtab = find_pc_sect_symtab (pc, section)) == 0)
309 bl = BLOCKVECTOR (symtab);
310 b = BLOCKVECTOR_BLOCK (bl, 0);
312 /* Then search that symtab for the smallest block that wins. */
313 /* Use binary search to find the last block that starts before PC. */
316 top = BLOCKVECTOR_NBLOCKS (bl);
318 while (top - bot > 1)
320 half = (top - bot + 1) >> 1;
321 b = BLOCKVECTOR_BLOCK (bl, bot + half);
322 if (BLOCK_START (b) <= pc)
328 /* Now search backward for a block that ends after PC. */
332 b = BLOCKVECTOR_BLOCK (bl, bot);
333 if (BLOCK_END (b) > pc)
344 /* Return the blockvector immediately containing the innermost lexical block
345 containing the specified pc value, or 0 if there is none.
346 Backward compatibility, no section. */
349 blockvector_for_pc (register CORE_ADDR pc, int *pindex)
351 return blockvector_for_pc_sect (pc, find_pc_mapped_section (pc),
355 /* Return the innermost lexical block containing the specified pc value
356 in the specified section, or 0 if there is none. */
359 block_for_pc_sect (register CORE_ADDR pc, struct sec *section)
361 register struct blockvector *bl;
364 bl = blockvector_for_pc_sect (pc, section, &index, NULL);
366 return BLOCKVECTOR_BLOCK (bl, index);
370 /* Return the innermost lexical block containing the specified pc value,
371 or 0 if there is none. Backward compatibility, no section. */
374 block_for_pc (register CORE_ADDR pc)
376 return block_for_pc_sect (pc, find_pc_mapped_section (pc));
379 /* Return the function containing pc value PC in section SECTION.
380 Returns 0 if function is not known. */
383 find_pc_sect_function (CORE_ADDR pc, struct sec *section)
385 register struct block *b = block_for_pc_sect (pc, section);
388 return block_function (b);
391 /* Return the function containing pc value PC.
392 Returns 0 if function is not known. Backward compatibility, no section */
395 find_pc_function (CORE_ADDR pc)
397 return find_pc_sect_function (pc, find_pc_mapped_section (pc));
400 /* These variables are used to cache the most recent result
401 * of find_pc_partial_function. */
403 static CORE_ADDR cache_pc_function_low = 0;
404 static CORE_ADDR cache_pc_function_high = 0;
405 static char *cache_pc_function_name = 0;
406 static struct sec *cache_pc_function_section = NULL;
408 /* Clear cache, e.g. when symbol table is discarded. */
411 clear_pc_function_cache (void)
413 cache_pc_function_low = 0;
414 cache_pc_function_high = 0;
415 cache_pc_function_name = (char *) 0;
416 cache_pc_function_section = NULL;
419 /* Finds the "function" (text symbol) that is smaller than PC but
420 greatest of all of the potential text symbols in SECTION. Sets
421 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
422 If ENDADDR is non-null, then set *ENDADDR to be the end of the
423 function (exclusive), but passing ENDADDR as non-null means that
424 the function might cause symbols to be read. This function either
425 succeeds or fails (not halfway succeeds). If it succeeds, it sets
426 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
427 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
431 find_pc_sect_partial_function (CORE_ADDR pc, asection *section, char **name,
432 CORE_ADDR *address, CORE_ADDR *endaddr)
434 struct partial_symtab *pst;
436 struct minimal_symbol *msymbol;
437 struct partial_symbol *psb;
438 struct obj_section *osect;
442 mapped_pc = overlay_mapped_address (pc, section);
444 if (mapped_pc >= cache_pc_function_low
445 && mapped_pc < cache_pc_function_high
446 && section == cache_pc_function_section)
447 goto return_cached_value;
449 /* If sigtramp is in the u area, it counts as a function (especially
450 important for step_1). */
451 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL))
453 cache_pc_function_low = SIGTRAMP_START (mapped_pc);
454 cache_pc_function_high = SIGTRAMP_END (mapped_pc);
455 cache_pc_function_name = "<sigtramp>";
456 cache_pc_function_section = section;
457 goto return_cached_value;
460 msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
461 pst = find_pc_sect_psymtab (mapped_pc, section);
464 /* Need to read the symbols to get a good value for the end address. */
465 if (endaddr != NULL && !pst->readin)
467 /* Need to get the terminal in case symbol-reading produces
469 target_terminal_ours_for_output ();
470 PSYMTAB_TO_SYMTAB (pst);
475 /* Checking whether the msymbol has a larger value is for the
476 "pathological" case mentioned in print_frame_info. */
477 f = find_pc_sect_function (mapped_pc, section);
480 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
481 >= SYMBOL_VALUE_ADDRESS (msymbol))))
483 cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
484 cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
485 cache_pc_function_name = SYMBOL_NAME (f);
486 cache_pc_function_section = section;
487 goto return_cached_value;
492 /* Now that static symbols go in the minimal symbol table, perhaps
493 we could just ignore the partial symbols. But at least for now
494 we use the partial or minimal symbol, whichever is larger. */
495 psb = find_pc_sect_psymbol (pst, mapped_pc, section);
498 && (msymbol == NULL ||
499 (SYMBOL_VALUE_ADDRESS (psb)
500 >= SYMBOL_VALUE_ADDRESS (msymbol))))
502 /* This case isn't being cached currently. */
504 *address = SYMBOL_VALUE_ADDRESS (psb);
506 *name = SYMBOL_NAME (psb);
507 /* endaddr non-NULL can't happen here. */
513 /* Not in the normal symbol tables, see if the pc is in a known section.
514 If it's not, then give up. This ensures that anything beyond the end
515 of the text seg doesn't appear to be part of the last function in the
518 osect = find_pc_sect_section (mapped_pc, section);
523 /* Must be in the minimal symbol table. */
526 /* No available symbol. */
536 cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
537 cache_pc_function_name = SYMBOL_NAME (msymbol);
538 cache_pc_function_section = section;
540 /* Use the lesser of the next minimal symbol in the same section, or
541 the end of the section, as the end of the function. */
543 /* Step over other symbols at this same address, and symbols in
544 other sections, to find the next symbol in this section with
545 a different address. */
547 for (i = 1; SYMBOL_NAME (msymbol + i) != NULL; i++)
549 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
550 && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
554 if (SYMBOL_NAME (msymbol + i) != NULL
555 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
556 cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
558 /* We got the start address from the last msymbol in the objfile.
559 So the end address is the end of the section. */
560 cache_pc_function_high = osect->endaddr;
566 if (pc_in_unmapped_range (pc, section))
567 *address = overlay_unmapped_address (cache_pc_function_low, section);
569 *address = cache_pc_function_low;
573 *name = cache_pc_function_name;
577 if (pc_in_unmapped_range (pc, section))
579 /* Because the high address is actually beyond the end of
580 the function (and therefore possibly beyond the end of
581 the overlay), we must actually convert (high - 1) and
582 then add one to that. */
584 *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
588 *endaddr = cache_pc_function_high;
594 /* Backward compatibility, no section argument. */
597 find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
602 section = find_pc_overlay (pc);
603 return find_pc_sect_partial_function (pc, section, name, address, endaddr);
606 /* Return the innermost stack frame executing inside of BLOCK,
607 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
610 block_innermost_frame (struct block *block)
612 struct frame_info *frame;
613 register CORE_ADDR start;
614 register CORE_ADDR end;
615 CORE_ADDR calling_pc;
620 start = BLOCK_START (block);
621 end = BLOCK_END (block);
626 frame = get_prev_frame (frame);
629 calling_pc = frame_address_in_block (frame);
630 if (calling_pc >= start && calling_pc < end)
635 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
636 below is for infrun.c, which may give the macro a pc without that
639 extern CORE_ADDR text_end;
642 deprecated_pc_in_call_dummy_before_text_end (CORE_ADDR pc, CORE_ADDR sp,
643 CORE_ADDR frame_address)
645 return ((pc) >= text_end - CALL_DUMMY_LENGTH
646 && (pc) <= text_end + DECR_PC_AFTER_BREAK);
650 deprecated_pc_in_call_dummy_after_text_end (CORE_ADDR pc, CORE_ADDR sp,
651 CORE_ADDR frame_address)
653 return ((pc) >= text_end
654 && (pc) <= text_end + CALL_DUMMY_LENGTH + DECR_PC_AFTER_BREAK);
657 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
658 top of the stack frame which we are checking, where "bottom" and
659 "top" refer to some section of memory which contains the code for
660 the call dummy. Calls to this macro assume that the contents of
661 SP_REGNUM and FP_REGNUM (or the saved values thereof), respectively,
662 are the things to pass.
664 This won't work on the 29k, where SP_REGNUM and FP_REGNUM don't
665 have that meaning, but the 29k doesn't use ON_STACK. This could be
666 fixed by generalizing this scheme, perhaps by passing in a frame
667 and adding a few fields, at least on machines which need them for
668 DEPRECATED_PC_IN_CALL_DUMMY.
670 Something simpler, like checking for the stack segment, doesn't work,
671 since various programs (threads implementations, gcc nested function
672 stubs, etc) may either allocate stack frames in another segment, or
673 allocate other kinds of code on the stack. */
676 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp,
677 CORE_ADDR frame_address)
679 return (INNER_THAN ((sp), (pc))
680 && (frame_address != 0)
681 && INNER_THAN ((pc), (frame_address)));
685 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp,
686 CORE_ADDR frame_address)
688 return ((pc) >= CALL_DUMMY_ADDRESS ()
689 && (pc) <= (CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK));
693 /* Function: frame_chain_valid
694 Returns true for a user frame or a call_function_by_hand dummy frame,
695 and false for the CRT0 start-up frame. Purpose is to terminate backtrace */
698 generic_file_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
700 if (DEPRECATED_PC_IN_CALL_DUMMY (frame_pc_unwind (fi), fp, fp))
701 return 1; /* don't prune CALL_DUMMY frames */
702 else /* fall back to default algorithm (see frame.h) */
704 && (INNER_THAN (get_frame_base (fi), fp)
705 || get_frame_base (fi) == fp)
706 && !inside_entry_file (frame_pc_unwind (fi)));
710 generic_func_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
712 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
713 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
714 return 1; /* don't prune CALL_DUMMY frames */
715 else /* fall back to default algorithm (see frame.h) */
717 && (INNER_THAN (get_frame_base (fi), fp)
718 || get_frame_base (fi) == fp)
719 && !inside_main_func (get_frame_pc (fi))
720 && !inside_entry_func (get_frame_pc (fi)));