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));
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;
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 innermost lexical block in execution
172 in a specified stack frame. The frame address is assumed valid.
174 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
175 address we used to choose the block. We use this to find a source
176 line, to decide which macro definitions are in scope.
178 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
179 PC, and may not really be a valid PC at all. For example, in the
180 caller of a function declared to never return, the code at the
181 return address will never be reached, so the call instruction may
182 be the very last instruction in the block. So the address we use
183 to choose the block is actually one byte before the return address
184 --- hopefully pointing us at the call instruction, or its delay
188 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
190 const CORE_ADDR pc = get_frame_address_in_block (frame);
195 return block_for_pc (pc);
199 get_pc_function_start (CORE_ADDR pc)
202 struct minimal_symbol *msymbol;
204 bl = block_for_pc (pc);
207 struct symbol *symbol = block_function (bl);
211 bl = SYMBOL_BLOCK_VALUE (symbol);
212 return BLOCK_START (bl);
216 msymbol = lookup_minimal_symbol_by_pc (pc);
219 CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);
221 if (find_pc_section (fstart))
228 /* Return the symbol for the function executing in frame FRAME. */
231 get_frame_function (struct frame_info *frame)
233 register struct block *bl = get_frame_block (frame, 0);
236 return block_function (bl);
240 /* Return the function containing pc value PC in section SECTION.
241 Returns 0 if function is not known. */
244 find_pc_sect_function (CORE_ADDR pc, struct sec *section)
246 register struct block *b = block_for_pc_sect (pc, section);
249 return block_function (b);
252 /* Return the function containing pc value PC.
253 Returns 0 if function is not known. Backward compatibility, no section */
256 find_pc_function (CORE_ADDR pc)
258 return find_pc_sect_function (pc, find_pc_mapped_section (pc));
261 /* These variables are used to cache the most recent result
262 * of find_pc_partial_function. */
264 static CORE_ADDR cache_pc_function_low = 0;
265 static CORE_ADDR cache_pc_function_high = 0;
266 static char *cache_pc_function_name = 0;
267 static struct sec *cache_pc_function_section = NULL;
269 /* Clear cache, e.g. when symbol table is discarded. */
272 clear_pc_function_cache (void)
274 cache_pc_function_low = 0;
275 cache_pc_function_high = 0;
276 cache_pc_function_name = (char *) 0;
277 cache_pc_function_section = NULL;
280 /* Finds the "function" (text symbol) that is smaller than PC but
281 greatest of all of the potential text symbols in SECTION. Sets
282 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
283 If ENDADDR is non-null, then set *ENDADDR to be the end of the
284 function (exclusive), but passing ENDADDR as non-null means that
285 the function might cause symbols to be read. This function either
286 succeeds or fails (not halfway succeeds). If it succeeds, it sets
287 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
288 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
292 find_pc_sect_partial_function (CORE_ADDR pc, asection *section, char **name,
293 CORE_ADDR *address, CORE_ADDR *endaddr)
295 struct partial_symtab *pst;
297 struct minimal_symbol *msymbol;
298 struct partial_symbol *psb;
299 struct obj_section *osect;
303 mapped_pc = overlay_mapped_address (pc, section);
305 if (mapped_pc >= cache_pc_function_low
306 && mapped_pc < cache_pc_function_high
307 && section == cache_pc_function_section)
308 goto return_cached_value;
310 /* If sigtramp is in the u area, it counts as a function (especially
311 important for step_1). */
312 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL))
314 cache_pc_function_low = SIGTRAMP_START (mapped_pc);
315 cache_pc_function_high = SIGTRAMP_END (mapped_pc);
316 cache_pc_function_name = "<sigtramp>";
317 cache_pc_function_section = section;
318 goto return_cached_value;
321 msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
322 pst = find_pc_sect_psymtab (mapped_pc, section);
325 /* Need to read the symbols to get a good value for the end address. */
326 if (endaddr != NULL && !pst->readin)
328 /* Need to get the terminal in case symbol-reading produces
330 target_terminal_ours_for_output ();
331 PSYMTAB_TO_SYMTAB (pst);
336 /* Checking whether the msymbol has a larger value is for the
337 "pathological" case mentioned in print_frame_info. */
338 f = find_pc_sect_function (mapped_pc, section);
341 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
342 >= SYMBOL_VALUE_ADDRESS (msymbol))))
344 cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
345 cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
346 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (f);
347 cache_pc_function_section = section;
348 goto return_cached_value;
353 /* Now that static symbols go in the minimal symbol table, perhaps
354 we could just ignore the partial symbols. But at least for now
355 we use the partial or minimal symbol, whichever is larger. */
356 psb = find_pc_sect_psymbol (pst, mapped_pc, section);
359 && (msymbol == NULL ||
360 (SYMBOL_VALUE_ADDRESS (psb)
361 >= SYMBOL_VALUE_ADDRESS (msymbol))))
363 /* This case isn't being cached currently. */
365 *address = SYMBOL_VALUE_ADDRESS (psb);
367 *name = DEPRECATED_SYMBOL_NAME (psb);
368 /* endaddr non-NULL can't happen here. */
374 /* Not in the normal symbol tables, see if the pc is in a known section.
375 If it's not, then give up. This ensures that anything beyond the end
376 of the text seg doesn't appear to be part of the last function in the
379 osect = find_pc_sect_section (mapped_pc, section);
384 /* Must be in the minimal symbol table. */
387 /* No available symbol. */
397 cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
398 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (msymbol);
399 cache_pc_function_section = section;
401 /* Use the lesser of the next minimal symbol in the same section, or
402 the end of the section, as the end of the function. */
404 /* Step over other symbols at this same address, and symbols in
405 other sections, to find the next symbol in this section with
406 a different address. */
408 for (i = 1; DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL; i++)
410 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
411 && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
415 if (DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL
416 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
417 cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
419 /* We got the start address from the last msymbol in the objfile.
420 So the end address is the end of the section. */
421 cache_pc_function_high = osect->endaddr;
427 if (pc_in_unmapped_range (pc, section))
428 *address = overlay_unmapped_address (cache_pc_function_low, section);
430 *address = cache_pc_function_low;
434 *name = cache_pc_function_name;
438 if (pc_in_unmapped_range (pc, section))
440 /* Because the high address is actually beyond the end of
441 the function (and therefore possibly beyond the end of
442 the overlay), we must actually convert (high - 1) and
443 then add one to that. */
445 *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
449 *endaddr = cache_pc_function_high;
455 /* Backward compatibility, no section argument. */
458 find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
463 section = find_pc_overlay (pc);
464 return find_pc_sect_partial_function (pc, section, name, address, endaddr);
467 /* Return the innermost stack frame executing inside of BLOCK,
468 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
471 block_innermost_frame (struct block *block)
473 struct frame_info *frame;
474 register CORE_ADDR start;
475 register CORE_ADDR end;
476 CORE_ADDR calling_pc;
481 start = BLOCK_START (block);
482 end = BLOCK_END (block);
487 frame = get_prev_frame (frame);
490 calling_pc = get_frame_address_in_block (frame);
491 if (calling_pc >= start && calling_pc < end)
496 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
497 below is for infrun.c, which may give the macro a pc without that
500 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
501 top of the stack frame which we are checking, where "bottom" and
502 "top" refer to some section of memory which contains the code for
503 the call dummy. Calls to this macro assume that the contents of
504 SP_REGNUM and DEPRECATED_FP_REGNUM (or the saved values thereof),
505 respectively, are the things to pass.
507 This won't work on the 29k, where SP_REGNUM and
508 DEPRECATED_FP_REGNUM don't have that meaning, but the 29k doesn't
509 use ON_STACK. This could be fixed by generalizing this scheme,
510 perhaps by passing in a frame and adding a few fields, at least on
511 machines which need them for DEPRECATED_PC_IN_CALL_DUMMY.
513 Something simpler, like checking for the stack segment, doesn't work,
514 since various programs (threads implementations, gcc nested function
515 stubs, etc) may either allocate stack frames in another segment, or
516 allocate other kinds of code on the stack. */
519 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp,
520 CORE_ADDR frame_address)
522 return (INNER_THAN ((sp), (pc))
523 && (frame_address != 0)
524 && INNER_THAN ((pc), (frame_address)));
528 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp,
529 CORE_ADDR frame_address)
531 return ((pc) >= CALL_DUMMY_ADDRESS ()
532 && (pc) <= (CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK));
535 /* Returns true for a user frame or a call_function_by_hand dummy
536 frame, and false for the CRT0 start-up frame. Purpose is to
537 terminate backtrace. */
540 legacy_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
542 /* Don't prune CALL_DUMMY frames. */
543 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
544 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
547 /* If the new frame pointer is zero, then it isn't valid. */
551 /* If the new frame would be inside (younger than) the previous frame,
552 then it isn't valid. */
553 if (INNER_THAN (fp, get_frame_base (fi)))
556 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
558 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
559 return DEPRECATED_FRAME_CHAIN_VALID (fp, fi);
561 /* If we're already inside the entry function for the main objfile, then it
563 if (inside_entry_func (get_frame_pc (fi)))
566 /* If we're inside the entry file, it isn't valid. */
567 /* NOTE/drow 2002-12-25: should there be a way to disable this check? It
568 assumes a single small entry file, and the way some debug readers (e.g.
569 dbxread) figure out which object is the entry file is somewhat hokey. */
570 if (inside_entry_file (frame_pc_unwind (fi)))