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 a specified PC value to see if it is in the range of addresses
76 that correspond to the main() function. See comments above for why
77 we might want to do this.
79 Typically called from DEPRECATED_FRAME_CHAIN_VALID.
81 A PC of zero is always considered to be the bottom of the stack. */
84 inside_main_func (CORE_ADDR pc
)
86 struct minimal_symbol
*msymbol
;
90 if (symfile_objfile
== 0)
93 msymbol
= lookup_minimal_symbol (main_name (), NULL
, symfile_objfile
);
95 /* If the addr range is not set up at symbol reading time, set it up
96 now. This is for DEPRECATED_FRAME_CHAIN_VALID_ALTERNATE. I do
97 this for coff, because it is unable to set it up and symbol
101 && symfile_objfile
->ei
.main_func_lowpc
== INVALID_ENTRY_LOWPC
102 && symfile_objfile
->ei
.main_func_highpc
== INVALID_ENTRY_HIGHPC
)
104 /* brobecker/2003-10-10: We used to rely on lookup_symbol() to search
105 the symbol associated to the main function. Unfortunately,
106 lookup_symbol() uses the current-language la_lookup_symbol_nonlocal
107 function to do the global symbol search. Depending on the language,
108 this can introduce certain side-effects, because certain languages
109 such as Ada for instance may find more than one match. So we prefer
110 to search the main function symbol using its address rather than
112 struct symbol
*mainsym
113 = find_pc_function (SYMBOL_VALUE_ADDRESS (msymbol
));
115 if (mainsym
&& SYMBOL_CLASS (mainsym
) == LOC_BLOCK
)
117 symfile_objfile
->ei
.main_func_lowpc
=
118 BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym
));
119 symfile_objfile
->ei
.main_func_highpc
=
120 BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym
));
124 /* Not in the normal symbol tables, see if "main" is in the partial
125 symbol table. If it's not, then give up. */
127 if (msymbol
!= NULL
&& MSYMBOL_TYPE (msymbol
) == mst_text
)
129 struct obj_section
*osect
130 = find_pc_sect_section (SYMBOL_VALUE_ADDRESS (msymbol
),
131 msymbol
->ginfo
.bfd_section
);
135 /* Step over other symbols at this same address, and
136 symbols in other sections, to find the next symbol in
137 this section with a different address. */
138 for (i
= 1; SYMBOL_LINKAGE_NAME (msymbol
+ i
) != NULL
; i
++)
140 if (SYMBOL_VALUE_ADDRESS (msymbol
+ i
) != SYMBOL_VALUE_ADDRESS (msymbol
)
141 && SYMBOL_BFD_SECTION (msymbol
+ i
) == SYMBOL_BFD_SECTION (msymbol
))
145 symfile_objfile
->ei
.main_func_lowpc
= SYMBOL_VALUE_ADDRESS (msymbol
);
147 /* Use the lesser of the next minimal symbol in the same
148 section, or the end of the section, as the end of the
150 if (SYMBOL_LINKAGE_NAME (msymbol
+ i
) != NULL
151 && SYMBOL_VALUE_ADDRESS (msymbol
+ i
) < osect
->endaddr
)
152 symfile_objfile
->ei
.main_func_highpc
= SYMBOL_VALUE_ADDRESS (msymbol
+ i
);
154 /* We got the start address from the last msymbol in the
155 objfile. So the end address is the end of the
157 symfile_objfile
->ei
.main_func_highpc
= osect
->endaddr
;
162 return (symfile_objfile
->ei
.main_func_lowpc
<= pc
&&
163 symfile_objfile
->ei
.main_func_highpc
> pc
);
166 /* Test a specified PC value to see if it is in the range of addresses
167 that correspond to the process entry point function. See comments
168 in objfiles.h for why we might want to do this.
170 Typically called from DEPRECATED_FRAME_CHAIN_VALID.
172 A PC of zero is always considered to be the bottom of the stack. */
175 inside_entry_func (CORE_ADDR pc
)
179 if (symfile_objfile
== 0)
181 if (CALL_DUMMY_LOCATION
== AT_ENTRY_POINT
)
183 /* Do not stop backtracing if the pc is in the call dummy
184 at the entry point. */
185 /* FIXME: Won't always work with zeros for the last two arguments */
186 if (DEPRECATED_PC_IN_CALL_DUMMY (pc
, 0, 0))
189 return (symfile_objfile
->ei
.entry_func_lowpc
<= pc
&&
190 symfile_objfile
->ei
.entry_func_highpc
> pc
);
193 /* Return nonzero if the function for this frame lacks a prologue. Many
194 machines can define FRAMELESS_FUNCTION_INVOCATION to just call this
198 frameless_look_for_prologue (struct frame_info
*frame
)
200 CORE_ADDR func_start
;
202 func_start
= get_frame_func (frame
);
205 func_start
+= FUNCTION_START_OFFSET
;
206 /* This is faster, since only care whether there *is* a
207 prologue, not how long it is. */
208 return PROLOGUE_FRAMELESS_P (func_start
);
210 else if (get_frame_pc (frame
) == 0)
211 /* A frame with a zero PC is usually created by dereferencing a
212 NULL function pointer, normally causing an immediate core dump
213 of the inferior. Mark function as frameless, as the inferior
214 has no chance of setting up a stack frame. */
217 /* If we can't find the start of the function, we don't really
218 know whether the function is frameless, but we should be able
219 to get a reasonable (i.e. best we can do under the
220 circumstances) backtrace by saying that it isn't. */
224 /* Return the innermost lexical block in execution
225 in a specified stack frame. The frame address is assumed valid.
227 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
228 address we used to choose the block. We use this to find a source
229 line, to decide which macro definitions are in scope.
231 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
232 PC, and may not really be a valid PC at all. For example, in the
233 caller of a function declared to never return, the code at the
234 return address will never be reached, so the call instruction may
235 be the very last instruction in the block. So the address we use
236 to choose the block is actually one byte before the return address
237 --- hopefully pointing us at the call instruction, or its delay
241 get_frame_block (struct frame_info
*frame
, CORE_ADDR
*addr_in_block
)
243 const CORE_ADDR pc
= get_frame_address_in_block (frame
);
248 return block_for_pc (pc
);
252 get_pc_function_start (CORE_ADDR pc
)
255 struct minimal_symbol
*msymbol
;
257 bl
= block_for_pc (pc
);
260 struct symbol
*symbol
= block_function (bl
);
264 bl
= SYMBOL_BLOCK_VALUE (symbol
);
265 return BLOCK_START (bl
);
269 msymbol
= lookup_minimal_symbol_by_pc (pc
);
272 CORE_ADDR fstart
= SYMBOL_VALUE_ADDRESS (msymbol
);
274 if (find_pc_section (fstart
))
281 /* Return the symbol for the function executing in frame FRAME. */
284 get_frame_function (struct frame_info
*frame
)
286 struct block
*bl
= get_frame_block (frame
, 0);
289 return block_function (bl
);
293 /* Return the function containing pc value PC in section SECTION.
294 Returns 0 if function is not known. */
297 find_pc_sect_function (CORE_ADDR pc
, struct sec
*section
)
299 struct block
*b
= block_for_pc_sect (pc
, section
);
302 return block_function (b
);
305 /* Return the function containing pc value PC.
306 Returns 0 if function is not known. Backward compatibility, no section */
309 find_pc_function (CORE_ADDR pc
)
311 return find_pc_sect_function (pc
, find_pc_mapped_section (pc
));
314 /* These variables are used to cache the most recent result
315 * of find_pc_partial_function. */
317 static CORE_ADDR cache_pc_function_low
= 0;
318 static CORE_ADDR cache_pc_function_high
= 0;
319 static char *cache_pc_function_name
= 0;
320 static struct sec
*cache_pc_function_section
= NULL
;
322 /* Clear cache, e.g. when symbol table is discarded. */
325 clear_pc_function_cache (void)
327 cache_pc_function_low
= 0;
328 cache_pc_function_high
= 0;
329 cache_pc_function_name
= (char *) 0;
330 cache_pc_function_section
= NULL
;
333 /* Finds the "function" (text symbol) that is smaller than PC but
334 greatest of all of the potential text symbols in SECTION. Sets
335 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
336 If ENDADDR is non-null, then set *ENDADDR to be the end of the
337 function (exclusive), but passing ENDADDR as non-null means that
338 the function might cause symbols to be read. This function either
339 succeeds or fails (not halfway succeeds). If it succeeds, it sets
340 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
341 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
345 find_pc_sect_partial_function (CORE_ADDR pc
, asection
*section
, char **name
,
346 CORE_ADDR
*address
, CORE_ADDR
*endaddr
)
348 struct partial_symtab
*pst
;
350 struct minimal_symbol
*msymbol
;
351 struct partial_symbol
*psb
;
352 struct obj_section
*osect
;
356 mapped_pc
= overlay_mapped_address (pc
, section
);
358 if (mapped_pc
>= cache_pc_function_low
359 && mapped_pc
< cache_pc_function_high
360 && section
== cache_pc_function_section
)
361 goto return_cached_value
;
363 /* If sigtramp is in the u area, it counts as a function (especially
364 important for step_1). */
365 if (SIGTRAMP_START_P () && PC_IN_SIGTRAMP (mapped_pc
, (char *) NULL
))
367 cache_pc_function_low
= SIGTRAMP_START (mapped_pc
);
368 cache_pc_function_high
= SIGTRAMP_END (mapped_pc
);
369 cache_pc_function_name
= "<sigtramp>";
370 cache_pc_function_section
= section
;
371 goto return_cached_value
;
374 msymbol
= lookup_minimal_symbol_by_pc_section (mapped_pc
, section
);
375 pst
= find_pc_sect_psymtab (mapped_pc
, section
);
378 /* Need to read the symbols to get a good value for the end address. */
379 if (endaddr
!= NULL
&& !pst
->readin
)
381 /* Need to get the terminal in case symbol-reading produces
383 target_terminal_ours_for_output ();
384 PSYMTAB_TO_SYMTAB (pst
);
389 /* Checking whether the msymbol has a larger value is for the
390 "pathological" case mentioned in print_frame_info. */
391 f
= find_pc_sect_function (mapped_pc
, section
);
394 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f
))
395 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
397 cache_pc_function_low
= BLOCK_START (SYMBOL_BLOCK_VALUE (f
));
398 cache_pc_function_high
= BLOCK_END (SYMBOL_BLOCK_VALUE (f
));
399 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (f
);
400 cache_pc_function_section
= section
;
401 goto return_cached_value
;
406 /* Now that static symbols go in the minimal symbol table, perhaps
407 we could just ignore the partial symbols. But at least for now
408 we use the partial or minimal symbol, whichever is larger. */
409 psb
= find_pc_sect_psymbol (pst
, mapped_pc
, section
);
412 && (msymbol
== NULL
||
413 (SYMBOL_VALUE_ADDRESS (psb
)
414 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
416 /* This case isn't being cached currently. */
418 *address
= SYMBOL_VALUE_ADDRESS (psb
);
420 *name
= DEPRECATED_SYMBOL_NAME (psb
);
421 /* endaddr non-NULL can't happen here. */
427 /* Not in the normal symbol tables, see if the pc is in a known section.
428 If it's not, then give up. This ensures that anything beyond the end
429 of the text seg doesn't appear to be part of the last function in the
432 osect
= find_pc_sect_section (mapped_pc
, section
);
437 /* Must be in the minimal symbol table. */
440 /* No available symbol. */
450 cache_pc_function_low
= SYMBOL_VALUE_ADDRESS (msymbol
);
451 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (msymbol
);
452 cache_pc_function_section
= section
;
454 /* Use the lesser of the next minimal symbol in the same section, or
455 the end of the section, as the end of the function. */
457 /* Step over other symbols at this same address, and symbols in
458 other sections, to find the next symbol in this section with
459 a different address. */
461 for (i
= 1; DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
; i
++)
463 if (SYMBOL_VALUE_ADDRESS (msymbol
+ i
) != SYMBOL_VALUE_ADDRESS (msymbol
)
464 && SYMBOL_BFD_SECTION (msymbol
+ i
) == SYMBOL_BFD_SECTION (msymbol
))
468 if (DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
469 && SYMBOL_VALUE_ADDRESS (msymbol
+ i
) < osect
->endaddr
)
470 cache_pc_function_high
= SYMBOL_VALUE_ADDRESS (msymbol
+ i
);
472 /* We got the start address from the last msymbol in the objfile.
473 So the end address is the end of the section. */
474 cache_pc_function_high
= osect
->endaddr
;
480 if (pc_in_unmapped_range (pc
, section
))
481 *address
= overlay_unmapped_address (cache_pc_function_low
, section
);
483 *address
= cache_pc_function_low
;
487 *name
= cache_pc_function_name
;
491 if (pc_in_unmapped_range (pc
, section
))
493 /* Because the high address is actually beyond the end of
494 the function (and therefore possibly beyond the end of
495 the overlay), we must actually convert (high - 1) and
496 then add one to that. */
498 *endaddr
= 1 + overlay_unmapped_address (cache_pc_function_high
- 1,
502 *endaddr
= cache_pc_function_high
;
508 /* Backward compatibility, no section argument. */
511 find_pc_partial_function (CORE_ADDR pc
, char **name
, CORE_ADDR
*address
,
516 section
= find_pc_overlay (pc
);
517 return find_pc_sect_partial_function (pc
, section
, name
, address
, endaddr
);
520 /* Return the innermost stack frame executing inside of BLOCK,
521 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
524 block_innermost_frame (struct block
*block
)
526 struct frame_info
*frame
;
529 CORE_ADDR calling_pc
;
534 start
= BLOCK_START (block
);
535 end
= BLOCK_END (block
);
540 frame
= get_prev_frame (frame
);
543 calling_pc
= get_frame_address_in_block (frame
);
544 if (calling_pc
>= start
&& calling_pc
< end
)
549 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
550 below is for infrun.c, which may give the macro a pc without that
553 /* Is the PC in a call dummy? SP and FRAME_ADDRESS are the bottom and
554 top of the stack frame which we are checking, where "bottom" and
555 "top" refer to some section of memory which contains the code for
556 the call dummy. Calls to this macro assume that the contents of
557 SP_REGNUM and DEPRECATED_FP_REGNUM (or the saved values thereof),
558 respectively, are the things to pass.
560 This won't work on the 29k, where SP_REGNUM and
561 DEPRECATED_FP_REGNUM don't have that meaning, but the 29k doesn't
562 use ON_STACK. This could be fixed by generalizing this scheme,
563 perhaps by passing in a frame and adding a few fields, at least on
564 machines which need them for DEPRECATED_PC_IN_CALL_DUMMY.
566 Something simpler, like checking for the stack segment, doesn't work,
567 since various programs (threads implementations, gcc nested function
568 stubs, etc) may either allocate stack frames in another segment, or
569 allocate other kinds of code on the stack. */
572 deprecated_pc_in_call_dummy_on_stack (CORE_ADDR pc
, CORE_ADDR sp
,
573 CORE_ADDR frame_address
)
575 return (INNER_THAN ((sp
), (pc
))
576 && (frame_address
!= 0)
577 && INNER_THAN ((pc
), (frame_address
)));
581 deprecated_pc_in_call_dummy_at_entry_point (CORE_ADDR pc
, CORE_ADDR sp
,
582 CORE_ADDR frame_address
)
584 CORE_ADDR addr
= entry_point_address ();
585 if (DEPRECATED_CALL_DUMMY_ADDRESS_P ())
586 addr
= DEPRECATED_CALL_DUMMY_ADDRESS ();
587 return ((pc
) >= addr
&& (pc
) <= (addr
+ DECR_PC_AFTER_BREAK
));
590 /* Returns true for a user frame or a call_function_by_hand dummy
591 frame, and false for the CRT0 start-up frame. Purpose is to
592 terminate backtrace. */
595 legacy_frame_chain_valid (CORE_ADDR fp
, struct frame_info
*fi
)
597 /* Don't prune CALL_DUMMY frames. */
598 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
599 && DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi
), 0, 0))
602 /* If the new frame pointer is zero, then it isn't valid. */
606 /* If the new frame would be inside (younger than) the previous frame,
607 then it isn't valid. */
608 if (INNER_THAN (fp
, get_frame_base (fi
)))
611 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
613 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
614 return DEPRECATED_FRAME_CHAIN_VALID (fp
, fi
);
616 /* If we're already inside the entry function for the main objfile, then it
618 if (inside_entry_func (get_frame_pc (fi
)))
621 /* If we're inside the entry file, it isn't valid. */
622 /* NOTE/drow 2002-12-25: should there be a way to disable this check? It
623 assumes a single small entry file, and the way some debug readers (e.g.
624 dbxread) figure out which object is the entry file is somewhat hokey. */
625 if (deprecated_inside_entry_file (frame_pc_unwind (fi
)))