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, after_prologue;
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 address of the PC for the given FRAME, ie the current PC value
172 if FRAME is the innermost frame, or the address adjusted to point to the
173 call instruction if not. */
176 frame_address_in_block (struct frame_info *frame)
178 CORE_ADDR pc = get_frame_pc (frame);
180 /* If we are not in the innermost frame, and we are not interrupted
181 by a signal, frame->pc points to the instruction following the
182 call. As a consequence, we need to get the address of the previous
183 instruction. Unfortunately, this is not straightforward to do, so
184 we just use the address minus one, which is a good enough
186 /* FIXME: cagney/2002-11-10: Should this instead test for
187 NORMAL_FRAME? A dummy frame (in fact all the abnormal frames)
188 save the PC value in the block. */
189 if (get_next_frame (frame) != 0
190 && get_frame_type (get_next_frame (frame)) != SIGTRAMP_FRAME)
196 /* Return the innermost lexical block in execution
197 in a specified stack frame. The frame address is assumed valid.
199 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
200 address we used to choose the block. We use this to find a source
201 line, to decide which macro definitions are in scope.
203 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
204 PC, and may not really be a valid PC at all. For example, in the
205 caller of a function declared to never return, the code at the
206 return address will never be reached, so the call instruction may
207 be the very last instruction in the block. So the address we use
208 to choose the block is actually one byte before the return address
209 --- hopefully pointing us at the call instruction, or its delay
213 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block)
215 const CORE_ADDR pc = frame_address_in_block (frame);
220 return block_for_pc (pc);
224 get_pc_function_start (CORE_ADDR pc)
227 struct minimal_symbol *msymbol;
229 bl = block_for_pc (pc);
232 struct symbol *symbol = block_function (bl);
236 bl = SYMBOL_BLOCK_VALUE (symbol);
237 return BLOCK_START (bl);
241 msymbol = lookup_minimal_symbol_by_pc (pc);
244 CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol);
246 if (find_pc_section (fstart))
253 /* Return the symbol for the function executing in frame FRAME. */
256 get_frame_function (struct frame_info *frame)
258 register struct block *bl = get_frame_block (frame, 0);
261 return block_function (bl);
265 /* Return the function containing pc value PC in section SECTION.
266 Returns 0 if function is not known. */
269 find_pc_sect_function (CORE_ADDR pc, struct sec *section)
271 register struct block *b = block_for_pc_sect (pc, section);
274 return block_function (b);
277 /* Return the function containing pc value PC.
278 Returns 0 if function is not known. Backward compatibility, no section */
281 find_pc_function (CORE_ADDR pc)
283 return find_pc_sect_function (pc, find_pc_mapped_section (pc));
286 /* These variables are used to cache the most recent result
287 * of find_pc_partial_function. */
289 static CORE_ADDR cache_pc_function_low = 0;
290 static CORE_ADDR cache_pc_function_high = 0;
291 static char *cache_pc_function_name = 0;
292 static struct sec *cache_pc_function_section = NULL;
294 /* Clear cache, e.g. when symbol table is discarded. */
297 clear_pc_function_cache (void)
299 cache_pc_function_low = 0;
300 cache_pc_function_high = 0;
301 cache_pc_function_name = (char *) 0;
302 cache_pc_function_section = NULL;
305 /* Finds the "function" (text symbol) that is smaller than PC but
306 greatest of all of the potential text symbols in SECTION. Sets
307 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
308 If ENDADDR is non-null, then set *ENDADDR to be the end of the
309 function (exclusive), but passing ENDADDR as non-null means that
310 the function might cause symbols to be read. This function either
311 succeeds or fails (not halfway succeeds). If it succeeds, it sets
312 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
313 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
317 find_pc_sect_partial_function (CORE_ADDR pc, asection *section, char **name,
318 CORE_ADDR *address, CORE_ADDR *endaddr)
320 struct partial_symtab *pst;
322 struct minimal_symbol *msymbol;
323 struct partial_symbol *psb;
324 struct obj_section *osect;
328 mapped_pc = overlay_mapped_address (pc, section);
330 if (mapped_pc >= cache_pc_function_low
331 && mapped_pc < cache_pc_function_high
332 && section == cache_pc_function_section)
333 goto return_cached_value;
335 /* If sigtramp is in the u area, it counts as a function (especially
336 important for step_1). */
337 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc, (char *) NULL))
339 cache_pc_function_low = SIGTRAMP_START (mapped_pc);
340 cache_pc_function_high = SIGTRAMP_END (mapped_pc);
341 cache_pc_function_name = "<sigtramp>";
342 cache_pc_function_section = section;
343 goto return_cached_value;
346 msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section);
347 pst = find_pc_sect_psymtab (mapped_pc, section);
350 /* Need to read the symbols to get a good value for the end address. */
351 if (endaddr != NULL && !pst->readin)
353 /* Need to get the terminal in case symbol-reading produces
355 target_terminal_ours_for_output ();
356 PSYMTAB_TO_SYMTAB (pst);
361 /* Checking whether the msymbol has a larger value is for the
362 "pathological" case mentioned in print_frame_info. */
363 f = find_pc_sect_function (mapped_pc, section);
366 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f))
367 >= SYMBOL_VALUE_ADDRESS (msymbol))))
369 cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f));
370 cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f));
371 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (f);
372 cache_pc_function_section = section;
373 goto return_cached_value;
378 /* Now that static symbols go in the minimal symbol table, perhaps
379 we could just ignore the partial symbols. But at least for now
380 we use the partial or minimal symbol, whichever is larger. */
381 psb = find_pc_sect_psymbol (pst, mapped_pc, section);
384 && (msymbol == NULL ||
385 (SYMBOL_VALUE_ADDRESS (psb)
386 >= SYMBOL_VALUE_ADDRESS (msymbol))))
388 /* This case isn't being cached currently. */
390 *address = SYMBOL_VALUE_ADDRESS (psb);
392 *name = DEPRECATED_SYMBOL_NAME (psb);
393 /* endaddr non-NULL can't happen here. */
399 /* Not in the normal symbol tables, see if the pc is in a known section.
400 If it's not, then give up. This ensures that anything beyond the end
401 of the text seg doesn't appear to be part of the last function in the
404 osect = find_pc_sect_section (mapped_pc, section);
409 /* Must be in the minimal symbol table. */
412 /* No available symbol. */
422 cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol);
423 cache_pc_function_name = DEPRECATED_SYMBOL_NAME (msymbol);
424 cache_pc_function_section = section;
426 /* Use the lesser of the next minimal symbol in the same section, or
427 the end of the section, as the end of the function. */
429 /* Step over other symbols at this same address, and symbols in
430 other sections, to find the next symbol in this section with
431 a different address. */
433 for (i = 1; DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL; i++)
435 if (SYMBOL_VALUE_ADDRESS (msymbol + i) != SYMBOL_VALUE_ADDRESS (msymbol)
436 && SYMBOL_BFD_SECTION (msymbol + i) == SYMBOL_BFD_SECTION (msymbol))
440 if (DEPRECATED_SYMBOL_NAME (msymbol + i) != NULL
441 && SYMBOL_VALUE_ADDRESS (msymbol + i) < osect->endaddr)
442 cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i);
444 /* We got the start address from the last msymbol in the objfile.
445 So the end address is the end of the section. */
446 cache_pc_function_high = osect->endaddr;
452 if (pc_in_unmapped_range (pc, section))
453 *address = overlay_unmapped_address (cache_pc_function_low, section);
455 *address = cache_pc_function_low;
459 *name = cache_pc_function_name;
463 if (pc_in_unmapped_range (pc, section))
465 /* Because the high address is actually beyond the end of
466 the function (and therefore possibly beyond the end of
467 the overlay), we must actually convert (high - 1) and
468 then add one to that. */
470 *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1,
474 *endaddr = cache_pc_function_high;
480 /* Backward compatibility, no section argument. */
483 find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address,
488 section = find_pc_overlay (pc);
489 return find_pc_sect_partial_function (pc, section, name, address, endaddr);
492 /* Return the innermost stack frame executing inside of BLOCK,
493 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
496 block_innermost_frame (struct block *block)
498 struct frame_info *frame;
499 register CORE_ADDR start;
500 register CORE_ADDR end;
501 CORE_ADDR calling_pc;
506 start = BLOCK_START (block);
507 end = BLOCK_END (block);
512 frame = get_prev_frame (frame);
515 calling_pc = frame_address_in_block (frame);
516 if (calling_pc >= start && calling_pc < end)
521 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
522 below is for infrun.c, which may give the macro a pc without that
525 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
526 top of the stack frame which we are checking, where "bottom" and
527 "top" refer to some section of memory which contains the code for
528 the call dummy. Calls to this macro assume that the contents of
529 SP_REGNUM and DEPRECATED_FP_REGNUM (or the saved values thereof),
530 respectively, are the things to pass.
532 This won't work on the 29k, where SP_REGNUM and
533 DEPRECATED_FP_REGNUM don't have that meaning, but the 29k doesn't
534 use ON_STACK. This could be fixed by generalizing this scheme,
535 perhaps by passing in a frame and adding a few fields, at least on
536 machines which need them for DEPRECATED_PC_IN_CALL_DUMMY.
538 Something simpler, like checking for the stack segment, doesn't work,
539 since various programs (threads implementations, gcc nested function
540 stubs, etc) may either allocate stack frames in another segment, or
541 allocate other kinds of code on the stack. */
544 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc, CORE_ADDR sp,
545 CORE_ADDR frame_address)
547 return (INNER_THAN ((sp), (pc))
548 && (frame_address != 0)
549 && INNER_THAN ((pc), (frame_address)));
553 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc, CORE_ADDR sp,
554 CORE_ADDR frame_address)
556 return ((pc) >= CALL_DUMMY_ADDRESS ()
557 && (pc) <= (CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK));
560 /* Returns true for a user frame or a call_function_by_hand dummy
561 frame, and false for the CRT0 start-up frame. Purpose is to
562 terminate backtrace. */
565 legacy_frame_chain_valid (CORE_ADDR fp, struct frame_info *fi)
567 /* Don't prune CALL_DUMMY frames. */
568 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
569 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi), 0, 0))
572 /* If the new frame pointer is zero, then it isn't valid. */
576 /* If the new frame would be inside (younger than) the previous frame,
577 then it isn't valid. */
578 if (INNER_THAN (fp, get_frame_base (fi)))
581 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
583 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
584 return DEPRECATED_FRAME_CHAIN_VALID (fp, fi);
586 /* If we're already inside the entry function for the main objfile, then it
588 if (inside_entry_func (get_frame_pc (fi)))
591 /* If we're inside the entry file, it isn't valid. */
592 /* NOTE/drow 2002-12-25: should there be a way to disable this check? It
593 assumes a single small entry file, and the way some debug readers (e.g.
594 dbxread) figure out which object is the entry file is somewhat hokey. */
595 if (inside_entry_file (frame_pc_unwind (fi)))