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 PC is inside the range of addresses that corresponds
160 to the process entry point function. */
163 inside_entry_func (CORE_ADDR pc
)
165 if (symfile_objfile
== 0)
168 if (CALL_DUMMY_LOCATION
== AT_ENTRY_POINT
)
170 /* Do not stop backtracing if the program counter is in the call
171 dummy at the entry point. */
172 /* FIXME: This won't always work with zeros for the last two
174 if (DEPRECATED_PC_IN_CALL_DUMMY (pc
, 0, 0))
178 return (symfile_objfile
->ei
.entry_func_lowpc
<= pc
179 && symfile_objfile
->ei
.entry_func_highpc
> pc
);
182 /* Return nonzero if the function for this frame lacks a prologue. Many
183 machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
187 frameless_look_for_prologue (struct frame_info
*frame
)
189 CORE_ADDR func_start
;
191 func_start
= get_frame_func (frame
);
194 func_start
+= FUNCTION_START_OFFSET
;
195 /* This is faster, since only care whether there *is* a
196 prologue, not how long it is. */
197 return PROLOGUE_FRAMELESS_P (func_start
);
199 else if (get_frame_pc (frame
) == 0)
200 /* A frame with a zero PC is usually created by dereferencing a
201 NULL function pointer, normally causing an immediate core dump
202 of the inferior. Mark function as frameless, as the inferior
203 has no chance of setting up a stack frame. */
206 /* If we can't find the start of the function, we don't really
207 know whether the function is frameless, but we should be able
208 to get a reasonable (i.e. best we can do under the
209 circumstances) backtrace by saying that it isn't. */
213 /* Return the innermost lexical block in execution
214 in a specified stack frame. The frame address is assumed valid.
216 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
217 address we used to choose the block. We use this to find a source
218 line, to decide which macro definitions are in scope.
220 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
221 PC, and may not really be a valid PC at all. For example, in the
222 caller of a function declared to never return, the code at the
223 return address will never be reached, so the call instruction may
224 be the very last instruction in the block. So the address we use
225 to choose the block is actually one byte before the return address
226 --- hopefully pointing us at the call instruction, or its delay
230 get_frame_block (struct frame_info
*frame
, CORE_ADDR
*addr_in_block
)
232 const CORE_ADDR pc
= get_frame_address_in_block (frame
);
237 return block_for_pc (pc
);
241 get_pc_function_start (CORE_ADDR pc
)
244 struct minimal_symbol
*msymbol
;
246 bl
= block_for_pc (pc
);
249 struct symbol
*symbol
= block_function (bl
);
253 bl
= SYMBOL_BLOCK_VALUE (symbol
);
254 return BLOCK_START (bl
);
258 msymbol
= lookup_minimal_symbol_by_pc (pc
);
261 CORE_ADDR fstart
= SYMBOL_VALUE_ADDRESS (msymbol
);
263 if (find_pc_section (fstart
))
270 /* Return the symbol for the function executing in frame FRAME. */
273 get_frame_function (struct frame_info
*frame
)
275 struct block
*bl
= get_frame_block (frame
, 0);
278 return block_function (bl
);
282 /* Return the function containing pc value PC in section SECTION.
283 Returns 0 if function is not known. */
286 find_pc_sect_function (CORE_ADDR pc
, struct bfd_section
*section
)
288 struct block
*b
= block_for_pc_sect (pc
, section
);
291 return block_function (b
);
294 /* Return the function containing pc value PC.
295 Returns 0 if function is not known. Backward compatibility, no section */
298 find_pc_function (CORE_ADDR pc
)
300 return find_pc_sect_function (pc
, find_pc_mapped_section (pc
));
303 /* These variables are used to cache the most recent result
304 * of find_pc_partial_function. */
306 static CORE_ADDR cache_pc_function_low
= 0;
307 static CORE_ADDR cache_pc_function_high
= 0;
308 static char *cache_pc_function_name
= 0;
309 static struct bfd_section
*cache_pc_function_section
= NULL
;
311 /* Clear cache, e.g. when symbol table is discarded. */
314 clear_pc_function_cache (void)
316 cache_pc_function_low
= 0;
317 cache_pc_function_high
= 0;
318 cache_pc_function_name
= (char *) 0;
319 cache_pc_function_section
= NULL
;
322 /* Finds the "function" (text symbol) that is smaller than PC but
323 greatest of all of the potential text symbols in SECTION. Sets
324 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
325 If ENDADDR is non-null, then set *ENDADDR to be the end of the
326 function (exclusive), but passing ENDADDR as non-null means that
327 the function might cause symbols to be read. This function either
328 succeeds or fails (not halfway succeeds). If it succeeds, it sets
329 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
330 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
334 find_pc_sect_partial_function (CORE_ADDR pc
, asection
*section
, char **name
,
335 CORE_ADDR
*address
, CORE_ADDR
*endaddr
)
337 struct partial_symtab
*pst
;
339 struct minimal_symbol
*msymbol
;
340 struct partial_symbol
*psb
;
341 struct obj_section
*osect
;
345 mapped_pc
= overlay_mapped_address (pc
, section
);
347 if (mapped_pc
>= cache_pc_function_low
348 && mapped_pc
< cache_pc_function_high
349 && section
== cache_pc_function_section
)
350 goto return_cached_value
;
352 /* If sigtramp is in the u area, it counts as a function (especially
353 important for step_1). */
354 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc
, (char *) NULL
))
356 cache_pc_function_low
= SIGTRAMP_START (mapped_pc
);
357 cache_pc_function_high
= SIGTRAMP_END (mapped_pc
);
358 cache_pc_function_name
= "<sigtramp>";
359 cache_pc_function_section
= section
;
360 goto return_cached_value
;
363 msymbol
= lookup_minimal_symbol_by_pc_section (mapped_pc
, section
);
364 pst
= find_pc_sect_psymtab (mapped_pc
, section
);
367 /* Need to read the symbols to get a good value for the end address. */
368 if (endaddr
!= NULL
&& !pst
->readin
)
370 /* Need to get the terminal in case symbol-reading produces
372 target_terminal_ours_for_output ();
373 PSYMTAB_TO_SYMTAB (pst
);
378 /* Checking whether the msymbol has a larger value is for the
379 "pathological" case mentioned in print_frame_info. */
380 f
= find_pc_sect_function (mapped_pc
, section
);
383 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f
))
384 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
386 cache_pc_function_low
= BLOCK_START (SYMBOL_BLOCK_VALUE (f
));
387 cache_pc_function_high
= BLOCK_END (SYMBOL_BLOCK_VALUE (f
));
388 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (f
);
389 cache_pc_function_section
= section
;
390 goto return_cached_value
;
395 /* Now that static symbols go in the minimal symbol table, perhaps
396 we could just ignore the partial symbols. But at least for now
397 we use the partial or minimal symbol, whichever is larger. */
398 psb
= find_pc_sect_psymbol (pst
, mapped_pc
, section
);
401 && (msymbol
== NULL
||
402 (SYMBOL_VALUE_ADDRESS (psb
)
403 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
405 /* This case isn't being cached currently. */
407 *address
= SYMBOL_VALUE_ADDRESS (psb
);
409 *name
= DEPRECATED_SYMBOL_NAME (psb
);
410 /* endaddr non-NULL can't happen here. */
416 /* Not in the normal symbol tables, see if the pc is in a known section.
417 If it's not, then give up. This ensures that anything beyond the end
418 of the text seg doesn't appear to be part of the last function in the
421 osect
= find_pc_sect_section (mapped_pc
, section
);
426 /* Must be in the minimal symbol table. */
429 /* No available symbol. */
439 cache_pc_function_low
= SYMBOL_VALUE_ADDRESS (msymbol
);
440 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (msymbol
);
441 cache_pc_function_section
= section
;
443 /* Use the lesser of the next minimal symbol in the same section, or
444 the end of the section, as the end of the function. */
446 /* Step over other symbols at this same address, and symbols in
447 other sections, to find the next symbol in this section with
448 a different address. */
450 for (i
= 1; DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
; i
++)
452 if (SYMBOL_VALUE_ADDRESS (msymbol
+ i
) != SYMBOL_VALUE_ADDRESS (msymbol
)
453 && SYMBOL_BFD_SECTION (msymbol
+ i
) == SYMBOL_BFD_SECTION (msymbol
))
457 if (DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
458 && SYMBOL_VALUE_ADDRESS (msymbol
+ i
) < osect
->endaddr
)
459 cache_pc_function_high
= SYMBOL_VALUE_ADDRESS (msymbol
+ i
);
461 /* We got the start address from the last msymbol in the objfile.
462 So the end address is the end of the section. */
463 cache_pc_function_high
= osect
->endaddr
;
469 if (pc_in_unmapped_range (pc
, section
))
470 *address
= overlay_unmapped_address (cache_pc_function_low
, section
);
472 *address
= cache_pc_function_low
;
476 *name
= cache_pc_function_name
;
480 if (pc_in_unmapped_range (pc
, section
))
482 /* Because the high address is actually beyond the end of
483 the function (and therefore possibly beyond the end of
484 the overlay), we must actually convert (high - 1) and
485 then add one to that. */
487 *endaddr
= 1 + overlay_unmapped_address (cache_pc_function_high
- 1,
491 *endaddr
= cache_pc_function_high
;
497 /* Backward compatibility, no section argument. */
500 find_pc_partial_function (CORE_ADDR pc
, char **name
, CORE_ADDR
*address
,
505 section
= find_pc_overlay (pc
);
506 return find_pc_sect_partial_function (pc
, section
, name
, address
, endaddr
);
509 /* Return the innermost stack frame executing inside of BLOCK,
510 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
513 block_innermost_frame (struct block
*block
)
515 struct frame_info
*frame
;
518 CORE_ADDR calling_pc
;
523 start
= BLOCK_START (block
);
524 end
= BLOCK_END (block
);
529 frame
= get_prev_frame (frame
);
532 calling_pc
= get_frame_address_in_block (frame
);
533 if (calling_pc
>= start
&& calling_pc
< end
)
538 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
539 below is for infrun.c, which may give the macro a pc without that
542 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
543 top of the stack frame which we are checking, where "bottom" and
544 "top" refer to some section of memory which contains the code for
545 the call dummy. Calls to this macro assume that the contents of
546 SP_REGNUM and DEPRECATED_FP_REGNUM (or the saved values thereof),
547 respectively, are the things to pass.
549 This won't work on the 29k, where SP_REGNUM and
550 DEPRECATED_FP_REGNUM don't have that meaning, but the 29k doesn't
551 use ON_STACK. This could be fixed by generalizing this scheme,
552 perhaps by passing in a frame and adding a few fields, at least on
553 machines which need them for DEPRECATED_PC_IN_CALL_DUMMY.
555 Something simpler, like checking for the stack segment, doesn't work,
556 since various programs (threads implementations, gcc nested function
557 stubs, etc) may either allocate stack frames in another segment, or
558 allocate other kinds of code on the stack. */
561 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc
, CORE_ADDR sp
,
562 CORE_ADDR frame_address
)
564 return (INNER_THAN ((sp
), (pc
))
565 && (frame_address
!= 0)
566 && INNER_THAN ((pc
), (frame_address
)));
570 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc
, CORE_ADDR sp
,
571 CORE_ADDR frame_address
)
573 CORE_ADDR addr
= entry_point_address ();
574 if (DEPRECATED_CALL_DUMMY_ADDRESS_P ())
575 addr
= DEPRECATED_CALL_DUMMY_ADDRESS ();
576 return ((pc
) >= addr
&& (pc
) <= (addr
+ DECR_PC_AFTER_BREAK
));
579 /* Returns true for a user frame or a call_function_by_hand dummy
580 frame, and false for the CRT0 start-up frame. Purpose is to
581 terminate backtrace. */
584 legacy_frame_chain_valid (CORE_ADDR fp
, struct frame_info
*fi
)
586 /* Don't prune CALL_DUMMY frames. */
587 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
588 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi
), 0, 0))
591 /* If the new frame pointer is zero, then it isn't valid. */
595 /* If the new frame would be inside (younger than) the previous frame,
596 then it isn't valid. */
597 if (INNER_THAN (fp
, get_frame_base (fi
)))
600 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
602 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
603 return DEPRECATED_FRAME_CHAIN_VALID (fp
, fi
);
605 /* If we're already inside the entry function for the main objfile, then it
607 if (inside_entry_func (get_frame_pc (fi
)))
610 /* If we're inside the entry file, it isn't valid. */
611 /* NOTE/drow 2002-12-25: should there be a way to disable this check? It
612 assumes a single small entry file, and the way some debug readers (e.g.
613 dbxread) figure out which object is the entry file is somewhat hokey. */
614 if (deprecated_inside_entry_file (frame_pc_unwind (fi
)))