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 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 a specified PC value to see if it is in the range of addresses
160 that correspond to the process entry point function. See comments
161 in objfiles.h for why we might want to do this.
163 Typically called from DEPRECATED_FRAME_CHAIN_VALID.
165 A PC of zero is always considered to be the bottom of the stack. */
168 inside_entry_func (CORE_ADDR pc)
172 if (symfile_objfile == 0)
174 if (CALL_DUMMY_LOCATION == AT_ENTRY_POINT)
176 /* Do not stop backtracing if the pc is in the call dummy
177 at the entry point. */
178 /* FIXME: Won't always work with zeros for the last two arguments */
179 if (DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0))
182 return (symfile_objfile->ei.entry_func_lowpc <= pc &&
183 symfile_objfile->ei.entry_func_highpc > pc);
186 /* Return nonzero if the function for this frame lacks a prologue. Many
187 machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
191 frameless_look_for_prologue (struct frame_info *frame)
193 CORE_ADDR func_start;
195 func_start = get_frame_func (frame);
198 func_start += FUNCTION_START_OFFSET;
199 /* This is faster, since only care whether there *is* a
200 prologue, not how long it is. */
201 return PROLOGUE_FRAMELESS_P (func_start);
203 else if (get_frame_pc (frame) == 0)
204 /* A frame with a zero PC is usually created by dereferencing a
205 NULL function pointer, normally causing an immediate core dump
206 of the inferior. Mark function as frameless, as the inferior
207 has no chance of setting up a stack frame. */
210 /* If we can't find the start of the function, we don't really
211 know whether the function is frameless, but we should be able
212 to get a reasonable (i.e. best we can do under the
213 circumstances) backtrace by saying that it isn't. */
217 /* Return the innermost lexical block in execution
218 in a specified stack frame. The frame address is assumed valid.
220 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
221 address we used to choose the block. We use this to find a source
222 line, to decide which macro definitions are in scope.
224 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
225 PC, and may not really be a valid PC at all. For example, in the
226 caller of a function declared to never return, the code at the
227 return address will never be reached, so the call instruction may
228 be the very last instruction in the block. So the address we use
229 to choose the block is actually one byte before the return address
230 --- hopefully pointing us at the call instruction, or its delay
234 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
236 const CORE_ADDR pc = get_frame_address_in_block (frame);
241 return block_for_pc (pc);
245 get_pc_function_start (CORE_ADDR pc)
248 struct minimal_symbol *msymbol;
250 bl = block_for_pc (pc);
253 struct symbol *symbol = block_function (bl);
257 bl = SYMBOL_BLOCK_VALUE (symbol);
258 return BLOCK_START (bl);
262 msymbol = lookup_minimal_symbol_by_pc (pc);
265 CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);
267 if (find_pc_section (fstart))
274 /* Return the symbol for the function executing in frame FRAME. */
277 get_frame_function (struct frame_info *frame)
279 struct block *bl = get_frame_block (frame, 0);
282 return block_function (bl);
286 /* Return the function containing pc value PC in section SECTION.
287 Returns 0 if function is not known. */
290 find_pc_sect_function (CORE_ADDR pc, struct bfd_section *section)
292 struct block *b = block_for_pc_sect (pc, section);
295 return block_function (b);
298 /* Return the function containing pc value PC.
299 Returns 0 if function is not known. Backward compatibility, no section */
302 find_pc_function (CORE_ADDR pc)
304 return find_pc_sect_function (pc, find_pc_mapped_section (pc));
307 /* These variables are used to cache the most recent result
308 * of find_pc_partial_function. */
310 static CORE_ADDR cache_pc_function_low = 0;
311 static CORE_ADDR cache_pc_function_high = 0;
312 static char *cache_pc_function_name = 0;
313 static struct bfd_section *cache_pc_function_section = NULL;
315 /* Clear cache, e.g. when symbol table is discarded. */
318 clear_pc_function_cache (void)
320 cache_pc_function_low = 0;
321 cache_pc_function_high = 0;
322 cache_pc_function_name = (char *) 0;
323 cache_pc_function_section = NULL;
326 /* Finds the "function" (text symbol) that is smaller than PC but
327 greatest of all of the potential text symbols in SECTION. Sets
328 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
329 If ENDADDR is non-null, then set *ENDADDR to be the end of the
330 function (exclusive), but passing ENDADDR as non-null means that
331 the function might cause symbols to be read. This function either
332 succeeds or fails (not halfway succeeds). If it succeeds, it sets
333 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
334 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
338 find_pc_sect_partial_function (CORE_ADDR pc, asection *section, char **name,
339 CORE_ADDR *address, CORE_ADDR *endaddr)
341 struct partial_symtab *pst;
343 struct minimal_symbol *msymbol;
344 struct partial_symbol *psb;
345 struct obj_section *osect;
349 mapped_pc = overlay_mapped_address (pc, section);
351 if (mapped_pc >= cache_pc_function_low
352 && mapped_pc < cache_pc_function_high
353 && section == cache_pc_function_section)
354 goto return_cached_value;
356 /* If sigtramp is in the u area, it counts as a function (especially
357 important for step_1). */
358 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL))
360 cache_pc_function_low = SIGTRAMP_START (mapped_pc);
361 cache_pc_function_high = SIGTRAMP_END (mapped_pc);
362 cache_pc_function_name = "<sigtramp>";
363 cache_pc_function_section = section;
364 goto return_cached_value;
367 msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
368 pst = find_pc_sect_psymtab (mapped_pc, section);
371 /* Need to read the symbols to get a good value for the end address. */
372 if (endaddr != NULL && !pst->readin)
374 /* Need to get the terminal in case symbol-reading produces
376 target_terminal_ours_for_output ();
377 PSYMTAB_TO_SYMTAB (pst);
382 /* Checking whether the msymbol has a larger value is for the
383 "pathological" case mentioned in print_frame_info. */
384 f = find_pc_sect_function (mapped_pc, section);
387 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
388 >= SYMBOL_VALUE_ADDRESS (msymbol))))
390 cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
391 cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
392 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (f);
393 cache_pc_function_section = section;
394 goto return_cached_value;
399 /* Now that static symbols go in the minimal symbol table, perhaps
400 we could just ignore the partial symbols. But at least for now
401 we use the partial or minimal symbol, whichever is larger. */
402 psb = find_pc_sect_psymbol (pst, mapped_pc, section);
405 && (msymbol == NULL ||
406 (SYMBOL_VALUE_ADDRESS (psb)
407 >= SYMBOL_VALUE_ADDRESS (msymbol))))
409 /* This case isn't being cached currently. */
411 *address = SYMBOL_VALUE_ADDRESS (psb);
413 *name = DEPRECATED_SYMBOL_NAME (psb);
414 /* endaddr non-NULL can't happen here. */
420 /* Not in the normal symbol tables, see if the pc is in a known section.
421 If it's not, then give up. This ensures that anything beyond the end
422 of the text seg doesn't appear to be part of the last function in the
425 osect = find_pc_sect_section (mapped_pc, section);
430 /* Must be in the minimal symbol table. */
433 /* No available symbol. */
443 cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
444 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (msymbol);
445 cache_pc_function_section = section;
447 /* Use the lesser of the next minimal symbol in the same section, or
448 the end of the section, as the end of the function. */
450 /* Step over other symbols at this same address, and symbols in
451 other sections, to find the next symbol in this section with
452 a different address. */
454 for (i = 1; DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL; i++)
456 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
457 && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
461 if (DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL
462 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
463 cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
465 /* We got the start address from the last msymbol in the objfile.
466 So the end address is the end of the section. */
467 cache_pc_function_high = osect->endaddr;
473 if (pc_in_unmapped_range (pc, section))
474 *address = overlay_unmapped_address (cache_pc_function_low, section);
476 *address = cache_pc_function_low;
480 *name = cache_pc_function_name;
484 if (pc_in_unmapped_range (pc, section))
486 /* Because the high address is actually beyond the end of
487 the function (and therefore possibly beyond the end of
488 the overlay), we must actually convert (high - 1) and
489 then add one to that. */
491 *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
495 *endaddr = cache_pc_function_high;
501 /* Backward compatibility, no section argument. */
504 find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
509 section = find_pc_overlay (pc);
510 return find_pc_sect_partial_function (pc, section, name, address, endaddr);
513 /* Return the innermost stack frame executing inside of BLOCK,
514 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
517 block_innermost_frame (struct block *block)
519 struct frame_info *frame;
522 CORE_ADDR calling_pc;
527 start = BLOCK_START (block);
528 end = BLOCK_END (block);
533 frame = get_prev_frame (frame);
536 calling_pc = get_frame_address_in_block (frame);
537 if (calling_pc >= start && calling_pc < end)
542 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
543 below is for infrun.c, which may give the macro a pc without that
546 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
547 top of the stack frame which we are checking, where "bottom" and
548 "top" refer to some section of memory which contains the code for
549 the call dummy. Calls to this macro assume that the contents of
550 SP_REGNUM and DEPRECATED_FP_REGNUM (or the saved values thereof),
551 respectively, are the things to pass.
553 This won't work on the 29k, where SP_REGNUM and
554 DEPRECATED_FP_REGNUM don't have that meaning, but the 29k doesn't
555 use ON_STACK. This could be fixed by generalizing this scheme,
556 perhaps by passing in a frame and adding a few fields, at least on
557 machines which need them for DEPRECATED_PC_IN_CALL_DUMMY.
559 Something simpler, like checking for the stack segment, doesn't work,
560 since various programs (threads implementations, gcc nested function
561 stubs, etc) may either allocate stack frames in another segment, or
562 allocate other kinds of code on the stack. */
565 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp,
566 CORE_ADDR frame_address)
568 return (INNER_THAN ((sp), (pc))
569 && (frame_address != 0)
570 && INNER_THAN ((pc), (frame_address)));
574 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp,
575 CORE_ADDR frame_address)
577 CORE_ADDR addr = entry_point_address ();
578 if (DEPRECATED_CALL_DUMMY_ADDRESS_P ())
579 addr = DEPRECATED_CALL_DUMMY_ADDRESS ();
580 return ((pc) >= addr && (pc) <= (addr + DECR_PC_AFTER_BREAK));
583 /* Returns true for a user frame or a call_function_by_hand dummy
584 frame, and false for the CRT0 start-up frame. Purpose is to
585 terminate backtrace. */
588 legacy_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
590 /* Don't prune CALL_DUMMY frames. */
591 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
592 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
595 /* If the new frame pointer is zero, then it isn't valid. */
599 /* If the new frame would be inside (younger than) the previous frame,
600 then it isn't valid. */
601 if (INNER_THAN (fp, get_frame_base (fi)))
604 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
606 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
607 return DEPRECATED_FRAME_CHAIN_VALID (fp, fi);
609 /* If we're already inside the entry function for the main objfile, then it
611 if (inside_entry_func (get_frame_pc (fi)))
614 /* If we're inside the entry file, it isn't valid. */
615 /* NOTE/drow 2002-12-25: should there be a way to disable this check? It
616 assumes a single small entry file, and the way some debug readers (e.g.
617 dbxread) figure out which object is the entry file is somewhat hokey. */
618 if (deprecated_inside_entry_file (frame_pc_unwind (fi)))