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 /* Return nonzero if the function for this frame lacks a prologue.
139 Many machines can define DEPRECATED_FRAMELESS_FUNCTION_INVOCATION
140 to just call this function. */
143 legacy_frameless_look_for_prologue (struct frame_info
*frame
)
145 CORE_ADDR func_start
;
147 func_start
= get_frame_func (frame
);
150 func_start
+= DEPRECATED_FUNCTION_START_OFFSET
;
151 /* NOTE: cagney/2004-02-09: Eliminated per-architecture
152 PROLOGUE_FRAMELESS_P call as architectures with custom
153 implementations had all been deleted. Eventually even this
154 function can go - GDB no longer tries to differentiate
155 between framed, frameless and stackless functions. They are
156 all now considered equally evil :-^. */
157 /* If skipping the prologue ends up skips nothing, there must be
158 no prologue and hence no code creating a frame. There for
159 the function is "frameless" :-/. */
160 return func_start
== SKIP_PROLOGUE (func_start
);
162 else if (get_frame_pc (frame
) == 0)
163 /* A frame with a zero PC is usually created by dereferencing a
164 NULL function pointer, normally causing an immediate core dump
165 of the inferior. Mark function as frameless, as the inferior
166 has no chance of setting up a stack frame. */
169 /* If we can't find the start of the function, we don't really
170 know whether the function is frameless, but we should be able
171 to get a reasonable (i.e. best we can do under the
172 circumstances) backtrace by saying that it isn't. */
176 /* Return the innermost lexical block in execution
177 in a specified stack frame. The frame address is assumed valid.
179 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code
180 address we used to choose the block. We use this to find a source
181 line, to decide which macro definitions are in scope.
183 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's
184 PC, and may not really be a valid PC at all. For example, in the
185 caller of a function declared to never return, the code at the
186 return address will never be reached, so the call instruction may
187 be the very last instruction in the block. So the address we use
188 to choose the block is actually one byte before the return address
189 --- hopefully pointing us at the call instruction, or its delay
193 get_frame_block (struct frame_info
*frame
, CORE_ADDR
*addr_in_block
)
195 const CORE_ADDR pc
= get_frame_address_in_block (frame
);
200 return block_for_pc (pc
);
204 get_pc_function_start (CORE_ADDR pc
)
207 struct minimal_symbol
*msymbol
;
209 bl
= block_for_pc (pc
);
212 struct symbol
*symbol
= block_function (bl
);
216 bl
= SYMBOL_BLOCK_VALUE (symbol
);
217 return BLOCK_START (bl
);
221 msymbol
= lookup_minimal_symbol_by_pc (pc
);
224 CORE_ADDR fstart
= SYMBOL_VALUE_ADDRESS (msymbol
);
226 if (find_pc_section (fstart
))
233 /* Return the symbol for the function executing in frame FRAME. */
236 get_frame_function (struct frame_info
*frame
)
238 struct block
*bl
= get_frame_block (frame
, 0);
241 return block_function (bl
);
245 /* Return the function containing pc value PC in section SECTION.
246 Returns 0 if function is not known. */
249 find_pc_sect_function (CORE_ADDR pc
, struct bfd_section
*section
)
251 struct block
*b
= block_for_pc_sect (pc
, section
);
254 return block_function (b
);
257 /* Return the function containing pc value PC.
258 Returns 0 if function is not known. Backward compatibility, no section */
261 find_pc_function (CORE_ADDR pc
)
263 return find_pc_sect_function (pc
, find_pc_mapped_section (pc
));
266 /* These variables are used to cache the most recent result
267 * of find_pc_partial_function. */
269 static CORE_ADDR cache_pc_function_low
= 0;
270 static CORE_ADDR cache_pc_function_high
= 0;
271 static char *cache_pc_function_name
= 0;
272 static struct bfd_section
*cache_pc_function_section
= NULL
;
274 /* Clear cache, e.g. when symbol table is discarded. */
277 clear_pc_function_cache (void)
279 cache_pc_function_low
= 0;
280 cache_pc_function_high
= 0;
281 cache_pc_function_name
= (char *) 0;
282 cache_pc_function_section
= NULL
;
285 /* Finds the "function" (text symbol) that is smaller than PC but
286 greatest of all of the potential text symbols in SECTION. Sets
287 *NAME and/or *ADDRESS conditionally if that pointer is non-null.
288 If ENDADDR is non-null, then set *ENDADDR to be the end of the
289 function (exclusive), but passing ENDADDR as non-null means that
290 the function might cause symbols to be read. This function either
291 succeeds or fails (not halfway succeeds). If it succeeds, it sets
292 *NAME, *ADDRESS, and *ENDADDR to real information and returns 1.
293 If it fails, it sets *NAME, *ADDRESS, and *ENDADDR to zero and
296 /* Backward compatibility, no section argument. */
299 find_pc_partial_function (CORE_ADDR pc
, char **name
, CORE_ADDR
*address
,
302 struct bfd_section
*section
;
303 struct partial_symtab
*pst
;
305 struct minimal_symbol
*msymbol
;
306 struct partial_symbol
*psb
;
307 struct obj_section
*osect
;
311 /* To ensure that the symbol returned belongs to the correct setion
312 (and that the last [random] symbol from the previous section
313 isn't returned) try to find the section containing PC. First try
314 the overlay code (which by default returns NULL); and second try
315 the normal section code (which almost always succeeds). */
316 section
= find_pc_overlay (pc
);
319 struct obj_section
*obj_section
= find_pc_section (pc
);
320 if (obj_section
== NULL
)
323 section
= obj_section
->the_bfd_section
;
326 mapped_pc
= overlay_mapped_address (pc
, section
);
328 if (mapped_pc
>= cache_pc_function_low
329 && mapped_pc
< cache_pc_function_high
330 && section
== cache_pc_function_section
)
331 goto return_cached_value
;
333 msymbol
= lookup_minimal_symbol_by_pc_section (mapped_pc
, section
);
334 pst
= find_pc_sect_psymtab (mapped_pc
, section
);
337 /* Need to read the symbols to get a good value for the end address. */
338 if (endaddr
!= NULL
&& !pst
->readin
)
340 /* Need to get the terminal in case symbol-reading produces
342 target_terminal_ours_for_output ();
343 PSYMTAB_TO_SYMTAB (pst
);
348 /* Checking whether the msymbol has a larger value is for the
349 "pathological" case mentioned in print_frame_info. */
350 f
= find_pc_sect_function (mapped_pc
, section
);
353 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f
))
354 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
356 cache_pc_function_low
= BLOCK_START (SYMBOL_BLOCK_VALUE (f
));
357 cache_pc_function_high
= BLOCK_END (SYMBOL_BLOCK_VALUE (f
));
358 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (f
);
359 cache_pc_function_section
= section
;
360 goto return_cached_value
;
365 /* Now that static symbols go in the minimal symbol table, perhaps
366 we could just ignore the partial symbols. But at least for now
367 we use the partial or minimal symbol, whichever is larger. */
368 psb
= find_pc_sect_psymbol (pst
, mapped_pc
, section
);
371 && (msymbol
== NULL
||
372 (SYMBOL_VALUE_ADDRESS (psb
)
373 >= SYMBOL_VALUE_ADDRESS (msymbol
))))
375 /* This case isn't being cached currently. */
377 *address
= SYMBOL_VALUE_ADDRESS (psb
);
379 *name
= DEPRECATED_SYMBOL_NAME (psb
);
380 /* endaddr non-NULL can't happen here. */
386 /* Not in the normal symbol tables, see if the pc is in a known section.
387 If it's not, then give up. This ensures that anything beyond the end
388 of the text seg doesn't appear to be part of the last function in the
391 osect
= find_pc_sect_section (mapped_pc
, section
);
396 /* Must be in the minimal symbol table. */
399 /* No available symbol. */
409 cache_pc_function_low
= SYMBOL_VALUE_ADDRESS (msymbol
);
410 cache_pc_function_name
= DEPRECATED_SYMBOL_NAME (msymbol
);
411 cache_pc_function_section
= section
;
413 /* Use the lesser of the next minimal symbol in the same section, or
414 the end of the section, as the end of the function. */
416 /* Step over other symbols at this same address, and symbols in
417 other sections, to find the next symbol in this section with
418 a different address. */
420 for (i
= 1; DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
; i
++)
422 if (SYMBOL_VALUE_ADDRESS (msymbol
+ i
) != SYMBOL_VALUE_ADDRESS (msymbol
)
423 && SYMBOL_BFD_SECTION (msymbol
+ i
) == SYMBOL_BFD_SECTION (msymbol
))
427 if (DEPRECATED_SYMBOL_NAME (msymbol
+ i
) != NULL
428 && SYMBOL_VALUE_ADDRESS (msymbol
+ i
) < osect
->endaddr
)
429 cache_pc_function_high
= SYMBOL_VALUE_ADDRESS (msymbol
+ i
);
431 /* We got the start address from the last msymbol in the objfile.
432 So the end address is the end of the section. */
433 cache_pc_function_high
= osect
->endaddr
;
439 if (pc_in_unmapped_range (pc
, section
))
440 *address
= overlay_unmapped_address (cache_pc_function_low
, section
);
442 *address
= cache_pc_function_low
;
446 *name
= cache_pc_function_name
;
450 if (pc_in_unmapped_range (pc
, section
))
452 /* Because the high address is actually beyond the end of
453 the function (and therefore possibly beyond the end of
454 the overlay), we must actually convert (high - 1) and
455 then add one to that. */
457 *endaddr
= 1 + overlay_unmapped_address (cache_pc_function_high
- 1,
461 *endaddr
= cache_pc_function_high
;
467 /* Return the innermost stack frame executing inside of BLOCK,
468 or NULL if there is no such frame. If BLOCK is NULL, just return NULL. */
471 block_innermost_frame (struct block
*block
)
473 struct frame_info
*frame
;
476 CORE_ADDR calling_pc
;
481 start
= BLOCK_START (block
);
482 end
= BLOCK_END (block
);
487 frame
= get_prev_frame (frame
);
490 calling_pc
= get_frame_address_in_block (frame
);
491 if (calling_pc
>= start
&& calling_pc
< end
)