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. */
31 #include "value.h" /* for read_register */
32 #include "target.h" /* for target_has_stack */
33 #include "inferior.h" /* for read_pc */
36 #include "gdb_assert.h"
37 #include "dummy-frame.h"
42 /* Prototypes for exported functions. */
44 void _initialize_blockframe (void);
46 /* Test whether PC is in the range of addresses that corresponds to
47 the "main" function. */
50 inside_main_func (CORE_ADDR pc
)
52 struct minimal_symbol
*msymbol
;
54 if (symfile_objfile
== 0)
57 msymbol
= lookup_minimal_symbol (main_name (), NULL
, symfile_objfile
);
59 /* If the address range hasn't been set up at symbol reading time,
63 && symfile_objfile
->ei
.main_func_lowpc
== INVALID_ENTRY_LOWPC
64 && symfile_objfile
->ei
.main_func_highpc
== INVALID_ENTRY_HIGHPC
)
66 /* brobecker/2003-10-10: We used to rely on lookup_symbol() to
67 search the symbol associated to the "main" function.
68 Unfortunately, lookup_symbol() uses the current-language
69 la_lookup_symbol_nonlocal function to do the global symbol
70 search. Depending on the language, this can introduce
71 certain side-effects, because certain languages, for instance
72 Ada, may find more than one match. Therefore we prefer to
73 search the "main" function symbol using its address rather
75 struct symbol
*mainsym
=
76 find_pc_function (SYMBOL_VALUE_ADDRESS (msymbol
));
78 if (mainsym
&& SYMBOL_CLASS (mainsym
) == LOC_BLOCK
)
80 symfile_objfile
->ei
.main_func_lowpc
=
81 BLOCK_START (SYMBOL_BLOCK_VALUE (mainsym
));
82 symfile_objfile
->ei
.main_func_highpc
=
83 BLOCK_END (SYMBOL_BLOCK_VALUE (mainsym
));
87 /* Not in the normal symbol tables, see if "main" is in the partial
88 symbol table. If it's not, then give up. */
89 if (msymbol
!= NULL
&& MSYMBOL_TYPE (msymbol
) == mst_text
)
91 CORE_ADDR maddr
= SYMBOL_VALUE_ADDRESS (msymbol
);
92 asection
*msect
= SYMBOL_BFD_SECTION (msymbol
);
93 struct obj_section
*osect
= find_pc_sect_section (maddr
, msect
);
99 /* Step over other symbols at this same address, and symbols
100 in other sections, to find the next symbol in this
101 section with a different address. */
102 for (i
= 1; SYMBOL_LINKAGE_NAME (msymbol
+ i
) != NULL
; i
++)
104 if (SYMBOL_VALUE_ADDRESS (msymbol
+ i
) != maddr
105 && SYMBOL_BFD_SECTION (msymbol
+ i
) == msect
)
109 symfile_objfile
->ei
.main_func_lowpc
= maddr
;
111 /* Use the lesser of the next minimal symbol in the same
112 section, or the end of the section, as the end of the
114 if (SYMBOL_LINKAGE_NAME (msymbol
+ i
) != NULL
115 && SYMBOL_VALUE_ADDRESS (msymbol
+ i
) < osect
->endaddr
)
116 symfile_objfile
->ei
.main_func_highpc
=
117 SYMBOL_VALUE_ADDRESS (msymbol
+ i
);
119 /* We got the start address from the last msymbol in the
120 objfile. So the end address is the end of the
122 symfile_objfile
->ei
.main_func_highpc
= osect
->endaddr
;
126 return (symfile_objfile
->ei
.main_func_lowpc
<= pc
127 && symfile_objfile
->ei
.main_func_highpc
> pc
);
130 /* Test whether THIS_FRAME is inside the process entry point function. */
133 inside_entry_func (struct frame_info
*this_frame
)
135 return (get_frame_func (this_frame
) == entry_point_address ());
138 /* Similar to inside_entry_func, but accomodating legacy frame code. */
141 legacy_inside_entry_func (CORE_ADDR pc
)
143 if (symfile_objfile
== 0)
146 if (CALL_DUMMY_LOCATION
== AT_ENTRY_POINT
)
148 /* Do not stop backtracing if the program counter is in the call
149 dummy at the entry point. */
150 /* FIXME: This won't always work with zeros for the last two
152 if (DEPRECATED_PC_IN_CALL_DUMMY (pc
, 0, 0))
156 return (symfile_objfile
->ei
.entry_func_lowpc
<= pc
157 && symfile_objfile
->ei
.entry_func_highpc
> pc
);
160 /* Return nonzero if the function for this frame lacks a prologue.
161 Many machines can define DEPRECATED_FRAMELESS_FUNCTION_INVOCATION
162 to just call this function. */
165 legacy_frameless_look_for_prologue (struct frame_info
*frame
)
167 CORE_ADDR func_start
;
169 func_start
= get_frame_func (frame
);
172 func_start
+= FUNCTION_START_OFFSET
;
173 /* NOTE: cagney/2004-02-09: Eliminated per-architecture
174 PROLOGUE_FRAMELESS_P call as architectures with custom
175 implementations had all been deleted. Eventually even this
176 function can go - GDB no longer tries to differentiate
177 between framed, frameless and stackless functions. They are
178 all now considered equally evil :-^. */
179 /* If skipping the prologue ends up skips nothing, there must be
180 no prologue and hence no code creating a frame. There for
181 the function is "frameless" :-/. */
182 return func_start
== SKIP_PROLOGUE (func_start
);
184 else if (get_frame_pc (frame
) == 0)
185 /* A frame with a zero PC is usually created by dereferencing a
186 NULL function pointer, normally causing an immediate core dump
187 of the inferior. Mark function as frameless, as the inferior
188 has no chance of setting up a stack frame. */
191 /* If we can't find the start of the function, we don't really
192 know whether the function is frameless, but we should be able
193 to get a reasonable (i.e. best we can do under the
194 circumstances) backtrace by saying that it isn't. */
198 /* Return the innermost lexical block in execution
199 in a specified stack frame. The frame address is assumed valid.
201 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
202 address we used to choose the block. We use this to find a source
203 line, to decide which macro definitions are in scope.
205 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
206 PC, and may not really be a valid PC at all. For example, in the
207 caller of a function declared to never return, the code at the
208 return address will never be reached, so the call instruction may
209 be the very last instruction in the block. So the address we use
210 to choose the block is actually one byte before the return address
211 --- hopefully pointing us at the call instruction, or its delay
215 get_frame_block (struct frame_info
*frame
, CORE_ADDR
*addr_in_block
)
217 const CORE_ADDR pc
= get_frame_address_in_block (frame
);
222 return block_for_pc (pc
);
226 get_pc_function_start (CORE_ADDR pc
)
229 struct minimal_symbol
*msymbol
;
231 bl
= block_for_pc (pc
);
234 struct symbol
*symbol
= block_function (bl
);
238 bl
= SYMBOL_BLOCK_VALUE (symbol
);
239 return BLOCK_START (bl
);
243 msymbol
= lookup_minimal_symbol_by_pc (pc
);
246 CORE_ADDR fstart
= SYMBOL_VALUE_ADDRESS (msymbol
);
248 if (find_pc_section (fstart
))
255 /* Return the symbol for the function executing in frame FRAME. */
258 get_frame_function (struct frame_info
*frame
)
260 struct block
*bl
= get_frame_block (frame
, 0);
263 return block_function (bl
);
267 /* Return the function containing pc value PC in section SECTION.
268 Returns 0 if function is not known. */
271 find_pc_sect_function (CORE_ADDR pc
, struct bfd_section
*section
)
273 struct block
*b
= block_for_pc_sect (pc
, section
);
276 return block_function (b
);
279 /* Return the function containing pc value PC.
280 Returns 0 if function is not known. Backward compatibility, no section */
283 find_pc_function (CORE_ADDR pc
)
285 return find_pc_sect_function (pc
, find_pc_mapped_section (pc
));
288 /* These variables are used to cache the most recent result
289 * of find_pc_partial_function. */
291 static CORE_ADDR cache_pc_function_low
= 0;
292 static CORE_ADDR cache_pc_function_high
= 0;
293 static char *cache_pc_function_name
= 0;
294 static struct bfd_section
*cache_pc_function_section
= NULL
;
296 /* Clear cache, e.g. when symbol table is discarded. */
299 clear_pc_function_cache (void)
301 cache_pc_function_low
= 0;
302 cache_pc_function_high
= 0;
303 cache_pc_function_name
= (char *) 0;
304 cache_pc_function_section
= NULL
;
307 /* Finds the "function" (text symbol) that is smaller than PC but
308 greatest of all of the potential text symbols in SECTION. Sets
309 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
310 If ENDADDR is non-null, then set *ENDADDR to be the end of the
311 function (exclusive), but passing ENDADDR as non-null means that
312 the function might cause symbols to be read. This function either
313 succeeds or fails (not halfway succeeds). If it succeeds, it sets
314 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
315 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
318 /* Backward compatibility, no section argument. */
321 find_pc_partial_function (CORE_ADDR pc
, char **name
, CORE_ADDR
*address
,
324 struct bfd_section
*section
;
325 struct partial_symtab
*pst
;
327 struct minimal_symbol
*msymbol
;
328 struct partial_symbol
*psb
;
329 struct obj_section
*osect
;
333 /* To ensure that the symbol returned belongs to the correct setion
334 (and that the last [random] symbol from the previous section
335 isn't returned) try to find the section containing PC. First try
336 the overlay code (which by default returns NULL); and second try
337 the normal section code (which almost always succeeds). */
338 section
= find_pc_overlay (pc
);
341 struct obj_section
*obj_section
= find_pc_section (pc
);
342 if (obj_section
== NULL
)
345 section
= obj_section
->the_bfd_section
;
348 mapped_pc
= overlay_mapped_address (pc
, section
);
350 if (mapped_pc
>= cache_pc_function_low
351 && mapped_pc
< cache_pc_function_high
352 && section
== cache_pc_function_section
)
353 goto return_cached_value
;
355 msymbol
= lookup_minimal_symbol_by_pc_section (mapped_pc
, section
);
356 pst
= find_pc_sect_psymtab (mapped_pc
, section
);
359 /* Need to read the symbols to get a good value for the end address. */
360 if (endaddr
!= NULL
&& !pst
->readin
)
362 /* Need to get the terminal in case symbol-reading produces
364 target_terminal_ours_for_output ();
365 PSYMTAB_TO_SYMTAB (pst
);
370 /* Checking whether the msymbol has a larger value is for the
371 "pathological" case mentioned in print_frame_info. */
372 f
= find_pc_sect_function (mapped_pc
, section
);
375 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f
))
376 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
378 cache_pc_function_low
= BLOCK_START (SYMBOL_BLOCK_VALUE (f
));
379 cache_pc_function_high
= BLOCK_END (SYMBOL_BLOCK_VALUE (f
));
380 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (f
);
381 cache_pc_function_section
= section
;
382 goto return_cached_value
;
387 /* Now that static symbols go in the minimal symbol table, perhaps
388 we could just ignore the partial symbols. But at least for now
389 we use the partial or minimal symbol, whichever is larger. */
390 psb
= find_pc_sect_psymbol (pst
, mapped_pc
, section
);
393 && (msymbol
== NULL
||
394 (SYMBOL_VALUE_ADDRESS (psb
)
395 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
397 /* This case isn't being cached currently. */
399 *address
= SYMBOL_VALUE_ADDRESS (psb
);
401 *name
= DEPRECATED_SYMBOL_NAME (psb
);
402 /* endaddr non-NULL can't happen here. */
408 /* Not in the normal symbol tables, see if the pc is in a known section.
409 If it's not, then give up. This ensures that anything beyond the end
410 of the text seg doesn't appear to be part of the last function in the
413 osect
= find_pc_sect_section (mapped_pc
, section
);
418 /* Must be in the minimal symbol table. */
421 /* No available symbol. */
431 cache_pc_function_low
= SYMBOL_VALUE_ADDRESS (msymbol
);
432 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (msymbol
);
433 cache_pc_function_section
= section
;
435 /* Use the lesser of the next minimal symbol in the same section, or
436 the end of the section, as the end of the function. */
438 /* Step over other symbols at this same address, and symbols in
439 other sections, to find the next symbol in this section with
440 a different address. */
442 for (i
= 1; DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
; i
++)
444 if (SYMBOL_VALUE_ADDRESS (msymbol
+ i
) != SYMBOL_VALUE_ADDRESS (msymbol
)
445 && SYMBOL_BFD_SECTION (msymbol
+ i
) == SYMBOL_BFD_SECTION (msymbol
))
449 if (DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
450 && SYMBOL_VALUE_ADDRESS (msymbol
+ i
) < osect
->endaddr
)
451 cache_pc_function_high
= SYMBOL_VALUE_ADDRESS (msymbol
+ i
);
453 /* We got the start address from the last msymbol in the objfile.
454 So the end address is the end of the section. */
455 cache_pc_function_high
= osect
->endaddr
;
461 if (pc_in_unmapped_range (pc
, section
))
462 *address
= overlay_unmapped_address (cache_pc_function_low
, section
);
464 *address
= cache_pc_function_low
;
468 *name
= cache_pc_function_name
;
472 if (pc_in_unmapped_range (pc
, section
))
474 /* Because the high address is actually beyond the end of
475 the function (and therefore possibly beyond the end of
476 the overlay), we must actually convert (high - 1) and
477 then add one to that. */
479 *endaddr
= 1 + overlay_unmapped_address (cache_pc_function_high
- 1,
483 *endaddr
= cache_pc_function_high
;
489 /* Return the innermost stack frame executing inside of BLOCK,
490 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
493 block_innermost_frame (struct block
*block
)
495 struct frame_info
*frame
;
498 CORE_ADDR calling_pc
;
503 start
= BLOCK_START (block
);
504 end
= BLOCK_END (block
);
509 frame
= get_prev_frame (frame
);
512 calling_pc
= get_frame_address_in_block (frame
);
513 if (calling_pc
>= start
&& calling_pc
< end
)
518 /* Are we in a call dummy? The code below which allows DECR_PC_AFTER_BREAK
519 below is for infrun.c, which may give the macro a pc without that
522 /* Returns true for a user frame or a call_function_by_hand dummy
523 frame, and false for the CRT0 start-up frame. Purpose is to
524 terminate backtrace. */
527 legacy_frame_chain_valid (CORE_ADDR fp
, struct frame_info
*fi
)
529 /* Don't prune CALL_DUMMY frames. */
530 if (DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (fi
), 0, 0))
533 /* If the new frame pointer is zero, then it isn't valid. */
537 /* If the new frame would be inside (younger than) the previous frame,
538 then it isn't valid. */
539 if (INNER_THAN (fp
, get_frame_base (fi
)))
542 /* If the architecture has a custom DEPRECATED_FRAME_CHAIN_VALID,
544 if (DEPRECATED_FRAME_CHAIN_VALID_P ())
545 return DEPRECATED_FRAME_CHAIN_VALID (fp
, fi
);
547 /* If we're already inside the entry function for the main objfile, then it
549 if (legacy_inside_entry_func (get_frame_pc (fi
)))