1 /* Cache and manage frames for GDB, the GNU debugger.
3 Copyright (C) 1986-2017 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "inferior.h" /* for inferior_ptid */
26 #include "user-regs.h"
27 #include "gdb_obstack.h"
28 #include "dummy-frame.h"
29 #include "sentinel-frame.h"
33 #include "frame-unwind.h"
34 #include "frame-base.h"
39 #include "gdbthread.h"
41 #include "inline-frame.h"
42 #include "tracepoint.h"
46 /* The sentinel frame terminates the innermost end of the frame chain.
47 If unwound, it returns the information needed to construct an
50 The current frame, which is the innermost frame, can be found at
51 sentinel_frame->prev. */
53 static struct frame_info
*sentinel_frame
;
55 static struct frame_info
*get_prev_frame_raw (struct frame_info
*this_frame
);
56 static const char *frame_stop_reason_symbol_string (enum unwind_stop_reason reason
);
58 /* Status of some values cached in the frame_info object. */
60 enum cached_copy_status
62 /* Value is unknown. */
65 /* We have a value. */
68 /* Value was not saved. */
71 /* Value is unavailable. */
75 /* We keep a cache of stack frames, each of which is a "struct
76 frame_info". The innermost one gets allocated (in
77 wait_for_inferior) each time the inferior stops; sentinel_frame
78 points to it. Additional frames get allocated (in get_prev_frame)
79 as needed, and are chained through the next and prev fields. Any
80 time that the frame cache becomes invalid (most notably when we
81 execute something, but also if we change how we interpret the
82 frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything
83 which reads new symbols)), we should call reinit_frame_cache. */
87 /* Level of this frame. The inner-most (youngest) frame is at level
88 0. As you move towards the outer-most (oldest) frame, the level
89 increases. This is a cached value. It could just as easily be
90 computed by counting back from the selected frame to the inner
92 /* NOTE: cagney/2002-04-05: Perhaps a level of ``-1'' should be
93 reserved to indicate a bogus frame - one that has been created
94 just to keep GDB happy (GDB always needs a frame). For the
95 moment leave this as speculation. */
98 /* The frame's program space. */
99 struct program_space
*pspace
;
101 /* The frame's address space. */
102 struct address_space
*aspace
;
104 /* The frame's low-level unwinder and corresponding cache. The
105 low-level unwinder is responsible for unwinding register values
106 for the previous frame. The low-level unwind methods are
107 selected based on the presence, or otherwise, of register unwind
108 information such as CFI. */
109 void *prologue_cache
;
110 const struct frame_unwind
*unwind
;
112 /* Cached copy of the previous frame's architecture. */
116 struct gdbarch
*arch
;
119 /* Cached copy of the previous frame's resume address. */
121 enum cached_copy_status status
;
125 /* Cached copy of the previous frame's function address. */
132 /* This frame's ID. */
136 struct frame_id value
;
139 /* The frame's high-level base methods, and corresponding cache.
140 The high level base methods are selected based on the frame's
142 const struct frame_base
*base
;
145 /* Pointers to the next (down, inner, younger) and previous (up,
146 outer, older) frame_info's in the frame cache. */
147 struct frame_info
*next
; /* down, inner, younger */
149 struct frame_info
*prev
; /* up, outer, older */
151 /* The reason why we could not set PREV, or UNWIND_NO_REASON if we
152 could. Only valid when PREV_P is set. */
153 enum unwind_stop_reason stop_reason
;
155 /* A frame specific string describing the STOP_REASON in more detail.
156 Only valid when PREV_P is set, but even then may still be NULL. */
157 const char *stop_string
;
160 /* A frame stash used to speed up frame lookups. Create a hash table
161 to stash frames previously accessed from the frame cache for
162 quicker subsequent retrieval. The hash table is emptied whenever
163 the frame cache is invalidated. */
165 static htab_t frame_stash
;
167 /* Internal function to calculate a hash from the frame_id addresses,
168 using as many valid addresses as possible. Frames below level 0
169 are not stored in the hash table. */
172 frame_addr_hash (const void *ap
)
174 const struct frame_info
*frame
= (const struct frame_info
*) ap
;
175 const struct frame_id f_id
= frame
->this_id
.value
;
178 gdb_assert (f_id
.stack_status
!= FID_STACK_INVALID
180 || f_id
.special_addr_p
);
182 if (f_id
.stack_status
== FID_STACK_VALID
)
183 hash
= iterative_hash (&f_id
.stack_addr
,
184 sizeof (f_id
.stack_addr
), hash
);
185 if (f_id
.code_addr_p
)
186 hash
= iterative_hash (&f_id
.code_addr
,
187 sizeof (f_id
.code_addr
), hash
);
188 if (f_id
.special_addr_p
)
189 hash
= iterative_hash (&f_id
.special_addr
,
190 sizeof (f_id
.special_addr
), hash
);
195 /* Internal equality function for the hash table. This function
196 defers equality operations to frame_id_eq. */
199 frame_addr_hash_eq (const void *a
, const void *b
)
201 const struct frame_info
*f_entry
= (const struct frame_info
*) a
;
202 const struct frame_info
*f_element
= (const struct frame_info
*) b
;
204 return frame_id_eq (f_entry
->this_id
.value
,
205 f_element
->this_id
.value
);
208 /* Internal function to create the frame_stash hash table. 100 seems
209 to be a good compromise to start the hash table at. */
212 frame_stash_create (void)
214 frame_stash
= htab_create (100,
220 /* Internal function to add a frame to the frame_stash hash table.
221 Returns false if a frame with the same ID was already stashed, true
225 frame_stash_add (struct frame_info
*frame
)
227 struct frame_info
**slot
;
229 /* Do not try to stash the sentinel frame. */
230 gdb_assert (frame
->level
>= 0);
232 slot
= (struct frame_info
**) htab_find_slot (frame_stash
,
236 /* If we already have a frame in the stack with the same id, we
237 either have a stack cycle (corrupted stack?), or some bug
238 elsewhere in GDB. In any case, ignore the duplicate and return
239 an indication to the caller. */
247 /* Internal function to search the frame stash for an entry with the
248 given frame ID. If found, return that frame. Otherwise return
251 static struct frame_info
*
252 frame_stash_find (struct frame_id id
)
254 struct frame_info dummy
;
255 struct frame_info
*frame
;
257 dummy
.this_id
.value
= id
;
258 frame
= (struct frame_info
*) htab_find (frame_stash
, &dummy
);
262 /* Internal function to invalidate the frame stash by removing all
263 entries in it. This only occurs when the frame cache is
267 frame_stash_invalidate (void)
269 htab_empty (frame_stash
);
272 /* Flag to control debugging. */
274 unsigned int frame_debug
;
276 show_frame_debug (struct ui_file
*file
, int from_tty
,
277 struct cmd_list_element
*c
, const char *value
)
279 fprintf_filtered (file
, _("Frame debugging is %s.\n"), value
);
282 /* Flag to indicate whether backtraces should stop at main et.al. */
284 static int backtrace_past_main
;
286 show_backtrace_past_main (struct ui_file
*file
, int from_tty
,
287 struct cmd_list_element
*c
, const char *value
)
289 fprintf_filtered (file
,
290 _("Whether backtraces should "
291 "continue past \"main\" is %s.\n"),
295 static int backtrace_past_entry
;
297 show_backtrace_past_entry (struct ui_file
*file
, int from_tty
,
298 struct cmd_list_element
*c
, const char *value
)
300 fprintf_filtered (file
, _("Whether backtraces should continue past the "
301 "entry point of a program is %s.\n"),
305 static unsigned int backtrace_limit
= UINT_MAX
;
307 show_backtrace_limit (struct ui_file
*file
, int from_tty
,
308 struct cmd_list_element
*c
, const char *value
)
310 fprintf_filtered (file
,
311 _("An upper bound on the number "
312 "of backtrace levels is %s.\n"),
318 fprint_field (struct ui_file
*file
, const char *name
, int p
, CORE_ADDR addr
)
321 fprintf_unfiltered (file
, "%s=%s", name
, hex_string (addr
));
323 fprintf_unfiltered (file
, "!%s", name
);
327 fprint_frame_id (struct ui_file
*file
, struct frame_id id
)
329 fprintf_unfiltered (file
, "{");
331 if (id
.stack_status
== FID_STACK_INVALID
)
332 fprintf_unfiltered (file
, "!stack");
333 else if (id
.stack_status
== FID_STACK_UNAVAILABLE
)
334 fprintf_unfiltered (file
, "stack=<unavailable>");
335 else if (id
.stack_status
== FID_STACK_SENTINEL
)
336 fprintf_unfiltered (file
, "stack=<sentinel>");
338 fprintf_unfiltered (file
, "stack=%s", hex_string (id
.stack_addr
));
339 fprintf_unfiltered (file
, ",");
341 fprint_field (file
, "code", id
.code_addr_p
, id
.code_addr
);
342 fprintf_unfiltered (file
, ",");
344 fprint_field (file
, "special", id
.special_addr_p
, id
.special_addr
);
346 if (id
.artificial_depth
)
347 fprintf_unfiltered (file
, ",artificial=%d", id
.artificial_depth
);
349 fprintf_unfiltered (file
, "}");
353 fprint_frame_type (struct ui_file
*file
, enum frame_type type
)
358 fprintf_unfiltered (file
, "NORMAL_FRAME");
361 fprintf_unfiltered (file
, "DUMMY_FRAME");
364 fprintf_unfiltered (file
, "INLINE_FRAME");
367 fprintf_unfiltered (file
, "TAILCALL_FRAME");
370 fprintf_unfiltered (file
, "SIGTRAMP_FRAME");
373 fprintf_unfiltered (file
, "ARCH_FRAME");
376 fprintf_unfiltered (file
, "SENTINEL_FRAME");
379 fprintf_unfiltered (file
, "<unknown type>");
385 fprint_frame (struct ui_file
*file
, struct frame_info
*fi
)
389 fprintf_unfiltered (file
, "<NULL frame>");
392 fprintf_unfiltered (file
, "{");
393 fprintf_unfiltered (file
, "level=%d", fi
->level
);
394 fprintf_unfiltered (file
, ",");
395 fprintf_unfiltered (file
, "type=");
396 if (fi
->unwind
!= NULL
)
397 fprint_frame_type (file
, fi
->unwind
->type
);
399 fprintf_unfiltered (file
, "<unknown>");
400 fprintf_unfiltered (file
, ",");
401 fprintf_unfiltered (file
, "unwind=");
402 if (fi
->unwind
!= NULL
)
403 gdb_print_host_address (fi
->unwind
, file
);
405 fprintf_unfiltered (file
, "<unknown>");
406 fprintf_unfiltered (file
, ",");
407 fprintf_unfiltered (file
, "pc=");
408 if (fi
->next
== NULL
|| fi
->next
->prev_pc
.status
== CC_UNKNOWN
)
409 fprintf_unfiltered (file
, "<unknown>");
410 else if (fi
->next
->prev_pc
.status
== CC_VALUE
)
411 fprintf_unfiltered (file
, "%s",
412 hex_string (fi
->next
->prev_pc
.value
));
413 else if (fi
->next
->prev_pc
.status
== CC_NOT_SAVED
)
414 val_print_not_saved (file
);
415 else if (fi
->next
->prev_pc
.status
== CC_UNAVAILABLE
)
416 val_print_unavailable (file
);
417 fprintf_unfiltered (file
, ",");
418 fprintf_unfiltered (file
, "id=");
420 fprint_frame_id (file
, fi
->this_id
.value
);
422 fprintf_unfiltered (file
, "<unknown>");
423 fprintf_unfiltered (file
, ",");
424 fprintf_unfiltered (file
, "func=");
425 if (fi
->next
!= NULL
&& fi
->next
->prev_func
.p
)
426 fprintf_unfiltered (file
, "%s", hex_string (fi
->next
->prev_func
.addr
));
428 fprintf_unfiltered (file
, "<unknown>");
429 fprintf_unfiltered (file
, "}");
432 /* Given FRAME, return the enclosing frame as found in real frames read-in from
433 inferior memory. Skip any previous frames which were made up by GDB.
434 Return FRAME if FRAME is a non-artificial frame.
435 Return NULL if FRAME is the start of an artificial-only chain. */
437 static struct frame_info
*
438 skip_artificial_frames (struct frame_info
*frame
)
440 /* Note we use get_prev_frame_always, and not get_prev_frame. The
441 latter will truncate the frame chain, leading to this function
442 unintentionally returning a null_frame_id (e.g., when the user
443 sets a backtrace limit).
445 Note that for record targets we may get a frame chain that consists
446 of artificial frames only. */
447 while (get_frame_type (frame
) == INLINE_FRAME
448 || get_frame_type (frame
) == TAILCALL_FRAME
)
450 frame
= get_prev_frame_always (frame
);
459 skip_unwritable_frames (struct frame_info
*frame
)
461 while (gdbarch_code_of_frame_writable (get_frame_arch (frame
), frame
) == 0)
463 frame
= get_prev_frame (frame
);
474 skip_tailcall_frames (struct frame_info
*frame
)
476 while (get_frame_type (frame
) == TAILCALL_FRAME
)
478 /* Note that for record targets we may get a frame chain that consists of
479 tailcall frames only. */
480 frame
= get_prev_frame (frame
);
488 /* Compute the frame's uniq ID that can be used to, later, re-find the
492 compute_frame_id (struct frame_info
*fi
)
494 gdb_assert (!fi
->this_id
.p
);
497 fprintf_unfiltered (gdb_stdlog
, "{ compute_frame_id (fi=%d) ",
499 /* Find the unwinder. */
500 if (fi
->unwind
== NULL
)
501 frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
502 /* Find THIS frame's ID. */
503 /* Default to outermost if no ID is found. */
504 fi
->this_id
.value
= outer_frame_id
;
505 fi
->unwind
->this_id (fi
, &fi
->prologue_cache
, &fi
->this_id
.value
);
506 gdb_assert (frame_id_p (fi
->this_id
.value
));
510 fprintf_unfiltered (gdb_stdlog
, "-> ");
511 fprint_frame_id (gdb_stdlog
, fi
->this_id
.value
);
512 fprintf_unfiltered (gdb_stdlog
, " }\n");
516 /* Return a frame uniq ID that can be used to, later, re-find the
520 get_frame_id (struct frame_info
*fi
)
523 return null_frame_id
;
529 /* If we haven't computed the frame id yet, then it must be that
530 this is the current frame. Compute it now, and stash the
531 result. The IDs of other frames are computed as soon as
532 they're created, in order to detect cycles. See
533 get_prev_frame_if_no_cycle. */
534 gdb_assert (fi
->level
== 0);
537 compute_frame_id (fi
);
539 /* Since this is the first frame in the chain, this should
541 stashed
= frame_stash_add (fi
);
542 gdb_assert (stashed
);
545 return fi
->this_id
.value
;
549 get_stack_frame_id (struct frame_info
*next_frame
)
551 return get_frame_id (skip_artificial_frames (next_frame
));
555 frame_unwind_caller_id (struct frame_info
*next_frame
)
557 struct frame_info
*this_frame
;
559 /* Use get_prev_frame_always, and not get_prev_frame. The latter
560 will truncate the frame chain, leading to this function
561 unintentionally returning a null_frame_id (e.g., when a caller
562 requests the frame ID of "main()"s caller. */
564 next_frame
= skip_artificial_frames (next_frame
);
565 if (next_frame
== NULL
)
566 return null_frame_id
;
568 this_frame
= get_prev_frame_always (next_frame
);
570 return get_frame_id (skip_artificial_frames (this_frame
));
572 return null_frame_id
;
575 const struct frame_id null_frame_id
= { 0 }; /* All zeros. */
576 const struct frame_id sentinel_frame_id
= { 0, 0, 0, FID_STACK_SENTINEL
, 0, 1, 0 };
577 const struct frame_id outer_frame_id
= { 0, 0, 0, FID_STACK_INVALID
, 0, 1, 0 };
580 frame_id_build_special (CORE_ADDR stack_addr
, CORE_ADDR code_addr
,
581 CORE_ADDR special_addr
)
583 struct frame_id id
= null_frame_id
;
585 id
.stack_addr
= stack_addr
;
586 id
.stack_status
= FID_STACK_VALID
;
587 id
.code_addr
= code_addr
;
589 id
.special_addr
= special_addr
;
590 id
.special_addr_p
= 1;
597 frame_id_build_unavailable_stack (CORE_ADDR code_addr
)
599 struct frame_id id
= null_frame_id
;
601 id
.stack_status
= FID_STACK_UNAVAILABLE
;
602 id
.code_addr
= code_addr
;
610 frame_id_build_unavailable_stack_special (CORE_ADDR code_addr
,
611 CORE_ADDR special_addr
)
613 struct frame_id id
= null_frame_id
;
615 id
.stack_status
= FID_STACK_UNAVAILABLE
;
616 id
.code_addr
= code_addr
;
618 id
.special_addr
= special_addr
;
619 id
.special_addr_p
= 1;
624 frame_id_build (CORE_ADDR stack_addr
, CORE_ADDR code_addr
)
626 struct frame_id id
= null_frame_id
;
628 id
.stack_addr
= stack_addr
;
629 id
.stack_status
= FID_STACK_VALID
;
630 id
.code_addr
= code_addr
;
636 frame_id_build_wild (CORE_ADDR stack_addr
)
638 struct frame_id id
= null_frame_id
;
640 id
.stack_addr
= stack_addr
;
641 id
.stack_status
= FID_STACK_VALID
;
646 frame_id_p (struct frame_id l
)
650 /* The frame is valid iff it has a valid stack address. */
651 p
= l
.stack_status
!= FID_STACK_INVALID
;
652 /* outer_frame_id is also valid. */
653 if (!p
&& memcmp (&l
, &outer_frame_id
, sizeof (l
)) == 0)
657 fprintf_unfiltered (gdb_stdlog
, "{ frame_id_p (l=");
658 fprint_frame_id (gdb_stdlog
, l
);
659 fprintf_unfiltered (gdb_stdlog
, ") -> %d }\n", p
);
665 frame_id_artificial_p (struct frame_id l
)
670 return (l
.artificial_depth
!= 0);
674 frame_id_eq (struct frame_id l
, struct frame_id r
)
678 if (l
.stack_status
== FID_STACK_INVALID
&& l
.special_addr_p
679 && r
.stack_status
== FID_STACK_INVALID
&& r
.special_addr_p
)
680 /* The outermost frame marker is equal to itself. This is the
681 dodgy thing about outer_frame_id, since between execution steps
682 we might step into another function - from which we can't
683 unwind either. More thought required to get rid of
686 else if (l
.stack_status
== FID_STACK_INVALID
687 || r
.stack_status
== FID_STACK_INVALID
)
688 /* Like a NaN, if either ID is invalid, the result is false.
689 Note that a frame ID is invalid iff it is the null frame ID. */
691 else if (l
.stack_status
!= r
.stack_status
|| l
.stack_addr
!= r
.stack_addr
)
692 /* If .stack addresses are different, the frames are different. */
694 else if (l
.code_addr_p
&& r
.code_addr_p
&& l
.code_addr
!= r
.code_addr
)
695 /* An invalid code addr is a wild card. If .code addresses are
696 different, the frames are different. */
698 else if (l
.special_addr_p
&& r
.special_addr_p
699 && l
.special_addr
!= r
.special_addr
)
700 /* An invalid special addr is a wild card (or unused). Otherwise
701 if special addresses are different, the frames are different. */
703 else if (l
.artificial_depth
!= r
.artificial_depth
)
704 /* If artifical depths are different, the frames must be different. */
707 /* Frames are equal. */
712 fprintf_unfiltered (gdb_stdlog
, "{ frame_id_eq (l=");
713 fprint_frame_id (gdb_stdlog
, l
);
714 fprintf_unfiltered (gdb_stdlog
, ",r=");
715 fprint_frame_id (gdb_stdlog
, r
);
716 fprintf_unfiltered (gdb_stdlog
, ") -> %d }\n", eq
);
721 /* Safety net to check whether frame ID L should be inner to
722 frame ID R, according to their stack addresses.
724 This method cannot be used to compare arbitrary frames, as the
725 ranges of valid stack addresses may be discontiguous (e.g. due
728 However, it can be used as safety net to discover invalid frame
729 IDs in certain circumstances. Assuming that NEXT is the immediate
730 inner frame to THIS and that NEXT and THIS are both NORMAL frames:
732 * The stack address of NEXT must be inner-than-or-equal to the stack
735 Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind
738 * If NEXT and THIS have different stack addresses, no other frame
739 in the frame chain may have a stack address in between.
741 Therefore, if frame_id_inner (TEST, THIS) holds, but
742 frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer
743 to a valid frame in the frame chain.
745 The sanity checks above cannot be performed when a SIGTRAMP frame
746 is involved, because signal handlers might be executed on a different
747 stack than the stack used by the routine that caused the signal
748 to be raised. This can happen for instance when a thread exceeds
749 its maximum stack size. In this case, certain compilers implement
750 a stack overflow strategy that cause the handler to be run on a
754 frame_id_inner (struct gdbarch
*gdbarch
, struct frame_id l
, struct frame_id r
)
758 if (l
.stack_status
!= FID_STACK_VALID
|| r
.stack_status
!= FID_STACK_VALID
)
759 /* Like NaN, any operation involving an invalid ID always fails.
760 Likewise if either ID has an unavailable stack address. */
762 else if (l
.artificial_depth
> r
.artificial_depth
763 && l
.stack_addr
== r
.stack_addr
764 && l
.code_addr_p
== r
.code_addr_p
765 && l
.special_addr_p
== r
.special_addr_p
766 && l
.special_addr
== r
.special_addr
)
768 /* Same function, different inlined functions. */
769 const struct block
*lb
, *rb
;
771 gdb_assert (l
.code_addr_p
&& r
.code_addr_p
);
773 lb
= block_for_pc (l
.code_addr
);
774 rb
= block_for_pc (r
.code_addr
);
776 if (lb
== NULL
|| rb
== NULL
)
777 /* Something's gone wrong. */
780 /* This will return true if LB and RB are the same block, or
781 if the block with the smaller depth lexically encloses the
782 block with the greater depth. */
783 inner
= contained_in (lb
, rb
);
786 /* Only return non-zero when strictly inner than. Note that, per
787 comment in "frame.h", there is some fuzz here. Frameless
788 functions are not strictly inner than (same .stack but
789 different .code and/or .special address). */
790 inner
= gdbarch_inner_than (gdbarch
, l
.stack_addr
, r
.stack_addr
);
793 fprintf_unfiltered (gdb_stdlog
, "{ frame_id_inner (l=");
794 fprint_frame_id (gdb_stdlog
, l
);
795 fprintf_unfiltered (gdb_stdlog
, ",r=");
796 fprint_frame_id (gdb_stdlog
, r
);
797 fprintf_unfiltered (gdb_stdlog
, ") -> %d }\n", inner
);
803 frame_find_by_id (struct frame_id id
)
805 struct frame_info
*frame
, *prev_frame
;
807 /* ZERO denotes the null frame, let the caller decide what to do
808 about it. Should it instead return get_current_frame()? */
809 if (!frame_id_p (id
))
812 /* Check for the sentinel frame. */
813 if (frame_id_eq (id
, sentinel_frame_id
))
814 return sentinel_frame
;
816 /* Try using the frame stash first. Finding it there removes the need
817 to perform the search by looping over all frames, which can be very
818 CPU-intensive if the number of frames is very high (the loop is O(n)
819 and get_prev_frame performs a series of checks that are relatively
820 expensive). This optimization is particularly useful when this function
821 is called from another function (such as value_fetch_lazy, case
822 VALUE_LVAL (val) == lval_register) which already loops over all frames,
823 making the overall behavior O(n^2). */
824 frame
= frame_stash_find (id
);
828 for (frame
= get_current_frame (); ; frame
= prev_frame
)
830 struct frame_id self
= get_frame_id (frame
);
832 if (frame_id_eq (id
, self
))
833 /* An exact match. */
836 prev_frame
= get_prev_frame (frame
);
840 /* As a safety net to avoid unnecessary backtracing while trying
841 to find an invalid ID, we check for a common situation where
842 we can detect from comparing stack addresses that no other
843 frame in the current frame chain can have this ID. See the
844 comment at frame_id_inner for details. */
845 if (get_frame_type (frame
) == NORMAL_FRAME
846 && !frame_id_inner (get_frame_arch (frame
), id
, self
)
847 && frame_id_inner (get_frame_arch (prev_frame
), id
,
848 get_frame_id (prev_frame
)))
855 frame_unwind_pc (struct frame_info
*this_frame
)
857 if (this_frame
->prev_pc
.status
== CC_UNKNOWN
)
859 if (gdbarch_unwind_pc_p (frame_unwind_arch (this_frame
)))
861 struct gdbarch
*prev_gdbarch
;
865 /* The right way. The `pure' way. The one true way. This
866 method depends solely on the register-unwind code to
867 determine the value of registers in THIS frame, and hence
868 the value of this frame's PC (resume address). A typical
869 implementation is no more than:
871 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf);
872 return extract_unsigned_integer (buf, size of ISA_PC_REGNUM);
874 Note: this method is very heavily dependent on a correct
875 register-unwind implementation, it pays to fix that
876 method first; this method is frame type agnostic, since
877 it only deals with register values, it works with any
878 frame. This is all in stark contrast to the old
879 FRAME_SAVED_PC which would try to directly handle all the
880 different ways that a PC could be unwound. */
881 prev_gdbarch
= frame_unwind_arch (this_frame
);
885 pc
= gdbarch_unwind_pc (prev_gdbarch
, this_frame
);
888 CATCH (ex
, RETURN_MASK_ERROR
)
890 if (ex
.error
== NOT_AVAILABLE_ERROR
)
892 this_frame
->prev_pc
.status
= CC_UNAVAILABLE
;
895 fprintf_unfiltered (gdb_stdlog
,
896 "{ frame_unwind_pc (this_frame=%d)"
897 " -> <unavailable> }\n",
900 else if (ex
.error
== OPTIMIZED_OUT_ERROR
)
902 this_frame
->prev_pc
.status
= CC_NOT_SAVED
;
905 fprintf_unfiltered (gdb_stdlog
,
906 "{ frame_unwind_pc (this_frame=%d)"
907 " -> <not saved> }\n",
911 throw_exception (ex
);
917 this_frame
->prev_pc
.value
= pc
;
918 this_frame
->prev_pc
.status
= CC_VALUE
;
920 fprintf_unfiltered (gdb_stdlog
,
921 "{ frame_unwind_pc (this_frame=%d) "
924 hex_string (this_frame
->prev_pc
.value
));
928 internal_error (__FILE__
, __LINE__
, _("No unwind_pc method"));
931 if (this_frame
->prev_pc
.status
== CC_VALUE
)
932 return this_frame
->prev_pc
.value
;
933 else if (this_frame
->prev_pc
.status
== CC_UNAVAILABLE
)
934 throw_error (NOT_AVAILABLE_ERROR
, _("PC not available"));
935 else if (this_frame
->prev_pc
.status
== CC_NOT_SAVED
)
936 throw_error (OPTIMIZED_OUT_ERROR
, _("PC not saved"));
938 internal_error (__FILE__
, __LINE__
,
939 "unexpected prev_pc status: %d",
940 (int) this_frame
->prev_pc
.status
);
944 frame_unwind_caller_pc (struct frame_info
*this_frame
)
946 this_frame
= skip_artificial_frames (this_frame
);
948 /* We must have a non-artificial frame. The caller is supposed to check
949 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
951 gdb_assert (this_frame
!= NULL
);
953 return frame_unwind_pc (this_frame
);
957 get_frame_func_if_available (struct frame_info
*this_frame
, CORE_ADDR
*pc
)
959 struct frame_info
*next_frame
= this_frame
->next
;
961 if (!next_frame
->prev_func
.p
)
963 CORE_ADDR addr_in_block
;
965 /* Make certain that this, and not the adjacent, function is
967 if (!get_frame_address_in_block_if_available (this_frame
, &addr_in_block
))
969 next_frame
->prev_func
.p
= -1;
971 fprintf_unfiltered (gdb_stdlog
,
972 "{ get_frame_func (this_frame=%d)"
973 " -> unavailable }\n",
978 next_frame
->prev_func
.p
= 1;
979 next_frame
->prev_func
.addr
= get_pc_function_start (addr_in_block
);
981 fprintf_unfiltered (gdb_stdlog
,
982 "{ get_frame_func (this_frame=%d) -> %s }\n",
984 hex_string (next_frame
->prev_func
.addr
));
988 if (next_frame
->prev_func
.p
< 0)
995 *pc
= next_frame
->prev_func
.addr
;
1001 get_frame_func (struct frame_info
*this_frame
)
1005 if (!get_frame_func_if_available (this_frame
, &pc
))
1006 throw_error (NOT_AVAILABLE_ERROR
, _("PC not available"));
1011 static enum register_status
1012 do_frame_register_read (void *src
, int regnum
, gdb_byte
*buf
)
1014 if (!deprecated_frame_register_read ((struct frame_info
*) src
, regnum
, buf
))
1015 return REG_UNAVAILABLE
;
1020 std::unique_ptr
<struct regcache
>
1021 frame_save_as_regcache (struct frame_info
*this_frame
)
1023 struct address_space
*aspace
= get_frame_address_space (this_frame
);
1024 std::unique_ptr
<struct regcache
> regcache
1025 (new struct regcache (get_frame_arch (this_frame
), aspace
));
1027 regcache_save (regcache
.get (), do_frame_register_read
, this_frame
);
1032 frame_pop (struct frame_info
*this_frame
)
1034 struct frame_info
*prev_frame
;
1036 if (get_frame_type (this_frame
) == DUMMY_FRAME
)
1038 /* Popping a dummy frame involves restoring more than just registers.
1039 dummy_frame_pop does all the work. */
1040 dummy_frame_pop (get_frame_id (this_frame
), inferior_ptid
);
1044 /* Ensure that we have a frame to pop to. */
1045 prev_frame
= get_prev_frame_always (this_frame
);
1048 error (_("Cannot pop the initial frame."));
1050 /* Ignore TAILCALL_FRAME type frames, they were executed already before
1051 entering THISFRAME. */
1052 prev_frame
= skip_tailcall_frames (prev_frame
);
1054 if (prev_frame
== NULL
)
1055 error (_("Cannot find the caller frame."));
1057 /* Make a copy of all the register values unwound from this frame.
1058 Save them in a scratch buffer so that there isn't a race between
1059 trying to extract the old values from the current regcache while
1060 at the same time writing new values into that same cache. */
1061 std::unique_ptr
<struct regcache
> scratch
1062 = frame_save_as_regcache (prev_frame
);
1064 /* FIXME: cagney/2003-03-16: It should be possible to tell the
1065 target's register cache that it is about to be hit with a burst
1066 register transfer and that the sequence of register writes should
1067 be batched. The pair target_prepare_to_store() and
1068 target_store_registers() kind of suggest this functionality.
1069 Unfortunately, they don't implement it. Their lack of a formal
1070 definition can lead to targets writing back bogus values
1071 (arguably a bug in the target code mind). */
1072 /* Now copy those saved registers into the current regcache.
1073 Here, regcache_cpy() calls regcache_restore(). */
1074 regcache_cpy (get_current_regcache (), scratch
.get ());
1076 /* We've made right mess of GDB's local state, just discard
1078 reinit_frame_cache ();
1082 frame_register_unwind (struct frame_info
*frame
, int regnum
,
1083 int *optimizedp
, int *unavailablep
,
1084 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
1085 int *realnump
, gdb_byte
*bufferp
)
1087 struct value
*value
;
1089 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1090 that the value proper does not need to be fetched. */
1091 gdb_assert (optimizedp
!= NULL
);
1092 gdb_assert (lvalp
!= NULL
);
1093 gdb_assert (addrp
!= NULL
);
1094 gdb_assert (realnump
!= NULL
);
1095 /* gdb_assert (bufferp != NULL); */
1097 value
= frame_unwind_register_value (frame
, regnum
);
1099 gdb_assert (value
!= NULL
);
1101 *optimizedp
= value_optimized_out (value
);
1102 *unavailablep
= !value_entirely_available (value
);
1103 *lvalp
= VALUE_LVAL (value
);
1104 *addrp
= value_address (value
);
1105 if (*lvalp
== lval_register
)
1106 *realnump
= VALUE_REGNUM (value
);
1112 if (!*optimizedp
&& !*unavailablep
)
1113 memcpy (bufferp
, value_contents_all (value
),
1114 TYPE_LENGTH (value_type (value
)));
1116 memset (bufferp
, 0, TYPE_LENGTH (value_type (value
)));
1119 /* Dispose of the new value. This prevents watchpoints from
1120 trying to watch the saved frame pointer. */
1121 release_value (value
);
1126 frame_register (struct frame_info
*frame
, int regnum
,
1127 int *optimizedp
, int *unavailablep
, enum lval_type
*lvalp
,
1128 CORE_ADDR
*addrp
, int *realnump
, gdb_byte
*bufferp
)
1130 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1131 that the value proper does not need to be fetched. */
1132 gdb_assert (optimizedp
!= NULL
);
1133 gdb_assert (lvalp
!= NULL
);
1134 gdb_assert (addrp
!= NULL
);
1135 gdb_assert (realnump
!= NULL
);
1136 /* gdb_assert (bufferp != NULL); */
1138 /* Obtain the register value by unwinding the register from the next
1139 (more inner frame). */
1140 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
1141 frame_register_unwind (frame
->next
, regnum
, optimizedp
, unavailablep
,
1142 lvalp
, addrp
, realnump
, bufferp
);
1146 frame_unwind_register (struct frame_info
*frame
, int regnum
, gdb_byte
*buf
)
1152 enum lval_type lval
;
1154 frame_register_unwind (frame
, regnum
, &optimized
, &unavailable
,
1155 &lval
, &addr
, &realnum
, buf
);
1158 throw_error (OPTIMIZED_OUT_ERROR
,
1159 _("Register %d was not saved"), regnum
);
1161 throw_error (NOT_AVAILABLE_ERROR
,
1162 _("Register %d is not available"), regnum
);
1166 get_frame_register (struct frame_info
*frame
,
1167 int regnum
, gdb_byte
*buf
)
1169 frame_unwind_register (frame
->next
, regnum
, buf
);
1173 frame_unwind_register_value (struct frame_info
*frame
, int regnum
)
1175 struct gdbarch
*gdbarch
;
1176 struct value
*value
;
1178 gdb_assert (frame
!= NULL
);
1179 gdbarch
= frame_unwind_arch (frame
);
1183 fprintf_unfiltered (gdb_stdlog
,
1184 "{ frame_unwind_register_value "
1185 "(frame=%d,regnum=%d(%s),...) ",
1186 frame
->level
, regnum
,
1187 user_reg_map_regnum_to_name (gdbarch
, regnum
));
1190 /* Find the unwinder. */
1191 if (frame
->unwind
== NULL
)
1192 frame_unwind_find_by_frame (frame
, &frame
->prologue_cache
);
1194 /* Ask this frame to unwind its register. */
1195 value
= frame
->unwind
->prev_register (frame
, &frame
->prologue_cache
, regnum
);
1199 fprintf_unfiltered (gdb_stdlog
, "->");
1200 if (value_optimized_out (value
))
1202 fprintf_unfiltered (gdb_stdlog
, " ");
1203 val_print_optimized_out (value
, gdb_stdlog
);
1207 if (VALUE_LVAL (value
) == lval_register
)
1208 fprintf_unfiltered (gdb_stdlog
, " register=%d",
1209 VALUE_REGNUM (value
));
1210 else if (VALUE_LVAL (value
) == lval_memory
)
1211 fprintf_unfiltered (gdb_stdlog
, " address=%s",
1213 value_address (value
)));
1215 fprintf_unfiltered (gdb_stdlog
, " computed");
1217 if (value_lazy (value
))
1218 fprintf_unfiltered (gdb_stdlog
, " lazy");
1222 const gdb_byte
*buf
= value_contents (value
);
1224 fprintf_unfiltered (gdb_stdlog
, " bytes=");
1225 fprintf_unfiltered (gdb_stdlog
, "[");
1226 for (i
= 0; i
< register_size (gdbarch
, regnum
); i
++)
1227 fprintf_unfiltered (gdb_stdlog
, "%02x", buf
[i
]);
1228 fprintf_unfiltered (gdb_stdlog
, "]");
1232 fprintf_unfiltered (gdb_stdlog
, " }\n");
1239 get_frame_register_value (struct frame_info
*frame
, int regnum
)
1241 return frame_unwind_register_value (frame
->next
, regnum
);
1245 frame_unwind_register_signed (struct frame_info
*frame
, int regnum
)
1247 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
1248 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1249 int size
= register_size (gdbarch
, regnum
);
1250 struct value
*value
= frame_unwind_register_value (frame
, regnum
);
1252 gdb_assert (value
!= NULL
);
1254 if (value_optimized_out (value
))
1256 throw_error (OPTIMIZED_OUT_ERROR
,
1257 _("Register %d was not saved"), regnum
);
1259 if (!value_entirely_available (value
))
1261 throw_error (NOT_AVAILABLE_ERROR
,
1262 _("Register %d is not available"), regnum
);
1265 LONGEST r
= extract_signed_integer (value_contents_all (value
), size
,
1268 release_value (value
);
1274 get_frame_register_signed (struct frame_info
*frame
, int regnum
)
1276 return frame_unwind_register_signed (frame
->next
, regnum
);
1280 frame_unwind_register_unsigned (struct frame_info
*frame
, int regnum
)
1282 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
1283 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1284 int size
= register_size (gdbarch
, regnum
);
1285 struct value
*value
= frame_unwind_register_value (frame
, regnum
);
1287 gdb_assert (value
!= NULL
);
1289 if (value_optimized_out (value
))
1291 throw_error (OPTIMIZED_OUT_ERROR
,
1292 _("Register %d was not saved"), regnum
);
1294 if (!value_entirely_available (value
))
1296 throw_error (NOT_AVAILABLE_ERROR
,
1297 _("Register %d is not available"), regnum
);
1300 ULONGEST r
= extract_unsigned_integer (value_contents_all (value
), size
,
1303 release_value (value
);
1309 get_frame_register_unsigned (struct frame_info
*frame
, int regnum
)
1311 return frame_unwind_register_unsigned (frame
->next
, regnum
);
1315 read_frame_register_unsigned (struct frame_info
*frame
, int regnum
,
1318 struct value
*regval
= get_frame_register_value (frame
, regnum
);
1320 if (!value_optimized_out (regval
)
1321 && value_entirely_available (regval
))
1323 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1324 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1325 int size
= register_size (gdbarch
, VALUE_REGNUM (regval
));
1327 *val
= extract_unsigned_integer (value_contents (regval
), size
, byte_order
);
1335 put_frame_register (struct frame_info
*frame
, int regnum
,
1336 const gdb_byte
*buf
)
1338 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1342 enum lval_type lval
;
1345 frame_register (frame
, regnum
, &optim
, &unavail
,
1346 &lval
, &addr
, &realnum
, NULL
);
1348 error (_("Attempt to assign to a register that was not saved."));
1353 write_memory (addr
, buf
, register_size (gdbarch
, regnum
));
1357 regcache_cooked_write (get_current_regcache (), realnum
, buf
);
1360 error (_("Attempt to assign to an unmodifiable value."));
1364 /* This function is deprecated. Use get_frame_register_value instead,
1365 which provides more accurate information.
1367 Find and return the value of REGNUM for the specified stack frame.
1368 The number of bytes copied is REGISTER_SIZE (REGNUM).
1370 Returns 0 if the register value could not be found. */
1373 deprecated_frame_register_read (struct frame_info
*frame
, int regnum
,
1378 enum lval_type lval
;
1382 frame_register (frame
, regnum
, &optimized
, &unavailable
,
1383 &lval
, &addr
, &realnum
, myaddr
);
1385 return !optimized
&& !unavailable
;
1389 get_frame_register_bytes (struct frame_info
*frame
, int regnum
,
1390 CORE_ADDR offset
, int len
, gdb_byte
*myaddr
,
1391 int *optimizedp
, int *unavailablep
)
1393 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1398 /* Skip registers wholly inside of OFFSET. */
1399 while (offset
>= register_size (gdbarch
, regnum
))
1401 offset
-= register_size (gdbarch
, regnum
);
1405 /* Ensure that we will not read beyond the end of the register file.
1406 This can only ever happen if the debug information is bad. */
1408 numregs
= gdbarch_num_regs (gdbarch
) + gdbarch_num_pseudo_regs (gdbarch
);
1409 for (i
= regnum
; i
< numregs
; i
++)
1411 int thissize
= register_size (gdbarch
, i
);
1414 break; /* This register is not available on this architecture. */
1415 maxsize
+= thissize
;
1418 error (_("Bad debug information detected: "
1419 "Attempt to read %d bytes from registers."), len
);
1421 /* Copy the data. */
1424 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
1429 if (curr_len
== register_size (gdbarch
, regnum
))
1431 enum lval_type lval
;
1435 frame_register (frame
, regnum
, optimizedp
, unavailablep
,
1436 &lval
, &addr
, &realnum
, myaddr
);
1437 if (*optimizedp
|| *unavailablep
)
1442 struct value
*value
= frame_unwind_register_value (frame
->next
,
1444 gdb_assert (value
!= NULL
);
1445 *optimizedp
= value_optimized_out (value
);
1446 *unavailablep
= !value_entirely_available (value
);
1448 if (*optimizedp
|| *unavailablep
)
1450 release_value (value
);
1454 memcpy (myaddr
, value_contents_all (value
) + offset
, curr_len
);
1455 release_value (value
);
1471 put_frame_register_bytes (struct frame_info
*frame
, int regnum
,
1472 CORE_ADDR offset
, int len
, const gdb_byte
*myaddr
)
1474 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1476 /* Skip registers wholly inside of OFFSET. */
1477 while (offset
>= register_size (gdbarch
, regnum
))
1479 offset
-= register_size (gdbarch
, regnum
);
1483 /* Copy the data. */
1486 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
1491 if (curr_len
== register_size (gdbarch
, regnum
))
1493 put_frame_register (frame
, regnum
, myaddr
);
1497 struct value
*value
= frame_unwind_register_value (frame
->next
,
1499 gdb_assert (value
!= NULL
);
1501 memcpy ((char *) value_contents_writeable (value
) + offset
, myaddr
,
1503 put_frame_register (frame
, regnum
, value_contents_raw (value
));
1504 release_value (value
);
1515 /* Create a sentinel frame. */
1517 static struct frame_info
*
1518 create_sentinel_frame (struct program_space
*pspace
, struct regcache
*regcache
)
1520 struct frame_info
*frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1523 frame
->pspace
= pspace
;
1524 frame
->aspace
= get_regcache_aspace (regcache
);
1525 /* Explicitly initialize the sentinel frame's cache. Provide it
1526 with the underlying regcache. In the future additional
1527 information, such as the frame's thread will be added. */
1528 frame
->prologue_cache
= sentinel_frame_cache (regcache
);
1529 /* For the moment there is only one sentinel frame implementation. */
1530 frame
->unwind
= &sentinel_frame_unwind
;
1531 /* Link this frame back to itself. The frame is self referential
1532 (the unwound PC is the same as the pc), so make it so. */
1533 frame
->next
= frame
;
1534 /* The sentinel frame has a special ID. */
1535 frame
->this_id
.p
= 1;
1536 frame
->this_id
.value
= sentinel_frame_id
;
1539 fprintf_unfiltered (gdb_stdlog
, "{ create_sentinel_frame (...) -> ");
1540 fprint_frame (gdb_stdlog
, frame
);
1541 fprintf_unfiltered (gdb_stdlog
, " }\n");
1546 /* Cache for frame addresses already read by gdb. Valid only while
1547 inferior is stopped. Control variables for the frame cache should
1548 be local to this module. */
1550 static struct obstack frame_cache_obstack
;
1553 frame_obstack_zalloc (unsigned long size
)
1555 void *data
= obstack_alloc (&frame_cache_obstack
, size
);
1557 memset (data
, 0, size
);
1561 static struct frame_info
*get_prev_frame_always_1 (struct frame_info
*this_frame
);
1564 get_current_frame (void)
1566 struct frame_info
*current_frame
;
1568 /* First check, and report, the lack of registers. Having GDB
1569 report "No stack!" or "No memory" when the target doesn't even
1570 have registers is very confusing. Besides, "printcmd.exp"
1571 explicitly checks that ``print $pc'' with no registers prints "No
1573 if (!target_has_registers
)
1574 error (_("No registers."));
1575 if (!target_has_stack
)
1576 error (_("No stack."));
1577 if (!target_has_memory
)
1578 error (_("No memory."));
1579 /* Traceframes are effectively a substitute for the live inferior. */
1580 if (get_traceframe_number () < 0)
1581 validate_registers_access ();
1583 if (sentinel_frame
== NULL
)
1585 create_sentinel_frame (current_program_space
, get_current_regcache ());
1587 /* Set the current frame before computing the frame id, to avoid
1588 recursion inside compute_frame_id, in case the frame's
1589 unwinder decides to do a symbol lookup (which depends on the
1590 selected frame's block).
1592 This call must always succeed. In particular, nothing inside
1593 get_prev_frame_always_1 should try to unwind from the
1594 sentinel frame, because that could fail/throw, and we always
1595 want to leave with the current frame created and linked in --
1596 we should never end up with the sentinel frame as outermost
1598 current_frame
= get_prev_frame_always_1 (sentinel_frame
);
1599 gdb_assert (current_frame
!= NULL
);
1601 return current_frame
;
1604 /* The "selected" stack frame is used by default for local and arg
1605 access. May be zero, for no selected frame. */
1607 static struct frame_info
*selected_frame
;
1610 has_stack_frames (void)
1612 if (!target_has_registers
|| !target_has_stack
|| !target_has_memory
)
1615 /* Traceframes are effectively a substitute for the live inferior. */
1616 if (get_traceframe_number () < 0)
1618 /* No current inferior, no frame. */
1619 if (ptid_equal (inferior_ptid
, null_ptid
))
1622 /* Don't try to read from a dead thread. */
1623 if (is_exited (inferior_ptid
))
1626 /* ... or from a spinning thread. */
1627 if (is_executing (inferior_ptid
))
1634 /* Return the selected frame. Always non-NULL (unless there isn't an
1635 inferior sufficient for creating a frame) in which case an error is
1639 get_selected_frame (const char *message
)
1641 if (selected_frame
== NULL
)
1643 if (message
!= NULL
&& !has_stack_frames ())
1644 error (("%s"), message
);
1645 /* Hey! Don't trust this. It should really be re-finding the
1646 last selected frame of the currently selected thread. This,
1647 though, is better than nothing. */
1648 select_frame (get_current_frame ());
1650 /* There is always a frame. */
1651 gdb_assert (selected_frame
!= NULL
);
1652 return selected_frame
;
1655 /* If there is a selected frame, return it. Otherwise, return NULL. */
1658 get_selected_frame_if_set (void)
1660 return selected_frame
;
1663 /* This is a variant of get_selected_frame() which can be called when
1664 the inferior does not have a frame; in that case it will return
1665 NULL instead of calling error(). */
1668 deprecated_safe_get_selected_frame (void)
1670 if (!has_stack_frames ())
1672 return get_selected_frame (NULL
);
1675 /* Select frame FI (or NULL - to invalidate the current frame). */
1678 select_frame (struct frame_info
*fi
)
1680 selected_frame
= fi
;
1681 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
1682 frame is being invalidated. */
1684 /* FIXME: kseitz/2002-08-28: It would be nice to call
1685 selected_frame_level_changed_event() right here, but due to limitations
1686 in the current interfaces, we would end up flooding UIs with events
1687 because select_frame() is used extensively internally.
1689 Once we have frame-parameterized frame (and frame-related) commands,
1690 the event notification can be moved here, since this function will only
1691 be called when the user's selected frame is being changed. */
1693 /* Ensure that symbols for this frame are read in. Also, determine the
1694 source language of this frame, and switch to it if desired. */
1699 /* We retrieve the frame's symtab by using the frame PC.
1700 However we cannot use the frame PC as-is, because it usually
1701 points to the instruction following the "call", which is
1702 sometimes the first instruction of another function. So we
1703 rely on get_frame_address_in_block() which provides us with a
1704 PC which is guaranteed to be inside the frame's code
1706 if (get_frame_address_in_block_if_available (fi
, &pc
))
1708 struct compunit_symtab
*cust
= find_pc_compunit_symtab (pc
);
1711 && compunit_language (cust
) != current_language
->la_language
1712 && compunit_language (cust
) != language_unknown
1713 && language_mode
== language_mode_auto
)
1714 set_language (compunit_language (cust
));
1719 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
1720 Always returns a non-NULL value. */
1723 create_new_frame (CORE_ADDR addr
, CORE_ADDR pc
)
1725 struct frame_info
*fi
;
1729 fprintf_unfiltered (gdb_stdlog
,
1730 "{ create_new_frame (addr=%s, pc=%s) ",
1731 hex_string (addr
), hex_string (pc
));
1734 fi
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1736 fi
->next
= create_sentinel_frame (current_program_space
,
1737 get_current_regcache ());
1739 /* Set/update this frame's cached PC value, found in the next frame.
1740 Do this before looking for this frame's unwinder. A sniffer is
1741 very likely to read this, and the corresponding unwinder is
1742 entitled to rely that the PC doesn't magically change. */
1743 fi
->next
->prev_pc
.value
= pc
;
1744 fi
->next
->prev_pc
.status
= CC_VALUE
;
1746 /* We currently assume that frame chain's can't cross spaces. */
1747 fi
->pspace
= fi
->next
->pspace
;
1748 fi
->aspace
= fi
->next
->aspace
;
1750 /* Select/initialize both the unwind function and the frame's type
1752 frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
1755 fi
->this_id
.value
= frame_id_build (addr
, pc
);
1759 fprintf_unfiltered (gdb_stdlog
, "-> ");
1760 fprint_frame (gdb_stdlog
, fi
);
1761 fprintf_unfiltered (gdb_stdlog
, " }\n");
1767 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
1768 innermost frame). Be careful to not fall off the bottom of the
1769 frame chain and onto the sentinel frame. */
1772 get_next_frame (struct frame_info
*this_frame
)
1774 if (this_frame
->level
> 0)
1775 return this_frame
->next
;
1780 /* Return the frame that THIS_FRAME calls. If THIS_FRAME is the
1781 innermost (i.e. current) frame, return the sentinel frame. Thus,
1782 unlike get_next_frame(), NULL will never be returned. */
1785 get_next_frame_sentinel_okay (struct frame_info
*this_frame
)
1787 gdb_assert (this_frame
!= NULL
);
1789 /* Note that, due to the manner in which the sentinel frame is
1790 constructed, this_frame->next still works even when this_frame
1791 is the sentinel frame. But we disallow it here anyway because
1792 calling get_next_frame_sentinel_okay() on the sentinel frame
1793 is likely a coding error. */
1794 gdb_assert (this_frame
!= sentinel_frame
);
1796 return this_frame
->next
;
1799 /* Observer for the target_changed event. */
1802 frame_observer_target_changed (struct target_ops
*target
)
1804 reinit_frame_cache ();
1807 /* Flush the entire frame cache. */
1810 reinit_frame_cache (void)
1812 struct frame_info
*fi
;
1814 /* Tear down all frame caches. */
1815 for (fi
= sentinel_frame
; fi
!= NULL
; fi
= fi
->prev
)
1817 if (fi
->prologue_cache
&& fi
->unwind
->dealloc_cache
)
1818 fi
->unwind
->dealloc_cache (fi
, fi
->prologue_cache
);
1819 if (fi
->base_cache
&& fi
->base
->unwind
->dealloc_cache
)
1820 fi
->base
->unwind
->dealloc_cache (fi
, fi
->base_cache
);
1823 /* Since we can't really be sure what the first object allocated was. */
1824 obstack_free (&frame_cache_obstack
, 0);
1825 obstack_init (&frame_cache_obstack
);
1827 if (sentinel_frame
!= NULL
)
1828 annotate_frames_invalid ();
1830 sentinel_frame
= NULL
; /* Invalidate cache */
1831 select_frame (NULL
);
1832 frame_stash_invalidate ();
1834 fprintf_unfiltered (gdb_stdlog
, "{ reinit_frame_cache () }\n");
1837 /* Find where a register is saved (in memory or another register).
1838 The result of frame_register_unwind is just where it is saved
1839 relative to this particular frame. */
1842 frame_register_unwind_location (struct frame_info
*this_frame
, int regnum
,
1843 int *optimizedp
, enum lval_type
*lvalp
,
1844 CORE_ADDR
*addrp
, int *realnump
)
1846 gdb_assert (this_frame
== NULL
|| this_frame
->level
>= 0);
1848 while (this_frame
!= NULL
)
1852 frame_register_unwind (this_frame
, regnum
, optimizedp
, &unavailable
,
1853 lvalp
, addrp
, realnump
, NULL
);
1858 if (*lvalp
!= lval_register
)
1862 this_frame
= get_next_frame (this_frame
);
1866 /* Called during frame unwinding to remove a previous frame pointer from a
1867 frame passed in ARG. */
1870 remove_prev_frame (void *arg
)
1872 struct frame_info
*this_frame
, *prev_frame
;
1874 this_frame
= (struct frame_info
*) arg
;
1875 prev_frame
= this_frame
->prev
;
1876 gdb_assert (prev_frame
!= NULL
);
1878 prev_frame
->next
= NULL
;
1879 this_frame
->prev
= NULL
;
1882 /* Get the previous raw frame, and check that it is not identical to
1883 same other frame frame already in the chain. If it is, there is
1884 most likely a stack cycle, so we discard it, and mark THIS_FRAME as
1885 outermost, with UNWIND_SAME_ID stop reason. Unlike the other
1886 validity tests, that compare THIS_FRAME and the next frame, we do
1887 this right after creating the previous frame, to avoid ever ending
1888 up with two frames with the same id in the frame chain. */
1890 static struct frame_info
*
1891 get_prev_frame_if_no_cycle (struct frame_info
*this_frame
)
1893 struct frame_info
*prev_frame
;
1894 struct cleanup
*prev_frame_cleanup
;
1896 prev_frame
= get_prev_frame_raw (this_frame
);
1898 /* Don't compute the frame id of the current frame yet. Unwinding
1899 the sentinel frame can fail (e.g., if the thread is gone and we
1900 can't thus read its registers). If we let the cycle detection
1901 code below try to compute a frame ID, then an error thrown from
1902 within the frame ID computation would result in the sentinel
1903 frame as outermost frame, which is bogus. Instead, we'll compute
1904 the current frame's ID lazily in get_frame_id. Note that there's
1905 no point in doing cycle detection when there's only one frame, so
1906 nothing is lost here. */
1907 if (prev_frame
->level
== 0)
1910 /* The cleanup will remove the previous frame that get_prev_frame_raw
1911 linked onto THIS_FRAME. */
1912 prev_frame_cleanup
= make_cleanup (remove_prev_frame
, this_frame
);
1914 compute_frame_id (prev_frame
);
1915 if (!frame_stash_add (prev_frame
))
1917 /* Another frame with the same id was already in the stash. We just
1918 detected a cycle. */
1921 fprintf_unfiltered (gdb_stdlog
, "-> ");
1922 fprint_frame (gdb_stdlog
, NULL
);
1923 fprintf_unfiltered (gdb_stdlog
, " // this frame has same ID }\n");
1925 this_frame
->stop_reason
= UNWIND_SAME_ID
;
1927 prev_frame
->next
= NULL
;
1928 this_frame
->prev
= NULL
;
1932 discard_cleanups (prev_frame_cleanup
);
1936 /* Helper function for get_prev_frame_always, this is called inside a
1937 TRY_CATCH block. Return the frame that called THIS_FRAME or NULL if
1938 there is no such frame. This may throw an exception. */
1940 static struct frame_info
*
1941 get_prev_frame_always_1 (struct frame_info
*this_frame
)
1943 struct gdbarch
*gdbarch
;
1945 gdb_assert (this_frame
!= NULL
);
1946 gdbarch
= get_frame_arch (this_frame
);
1950 fprintf_unfiltered (gdb_stdlog
, "{ get_prev_frame_always (this_frame=");
1951 if (this_frame
!= NULL
)
1952 fprintf_unfiltered (gdb_stdlog
, "%d", this_frame
->level
);
1954 fprintf_unfiltered (gdb_stdlog
, "<NULL>");
1955 fprintf_unfiltered (gdb_stdlog
, ") ");
1958 /* Only try to do the unwind once. */
1959 if (this_frame
->prev_p
)
1963 fprintf_unfiltered (gdb_stdlog
, "-> ");
1964 fprint_frame (gdb_stdlog
, this_frame
->prev
);
1965 fprintf_unfiltered (gdb_stdlog
, " // cached \n");
1967 return this_frame
->prev
;
1970 /* If the frame unwinder hasn't been selected yet, we must do so
1971 before setting prev_p; otherwise the check for misbehaved
1972 sniffers will think that this frame's sniffer tried to unwind
1973 further (see frame_cleanup_after_sniffer). */
1974 if (this_frame
->unwind
== NULL
)
1975 frame_unwind_find_by_frame (this_frame
, &this_frame
->prologue_cache
);
1977 this_frame
->prev_p
= 1;
1978 this_frame
->stop_reason
= UNWIND_NO_REASON
;
1980 /* If we are unwinding from an inline frame, all of the below tests
1981 were already performed when we unwound from the next non-inline
1982 frame. We must skip them, since we can not get THIS_FRAME's ID
1983 until we have unwound all the way down to the previous non-inline
1985 if (get_frame_type (this_frame
) == INLINE_FRAME
)
1986 return get_prev_frame_if_no_cycle (this_frame
);
1988 /* Check that this frame is unwindable. If it isn't, don't try to
1989 unwind to the prev frame. */
1990 this_frame
->stop_reason
1991 = this_frame
->unwind
->stop_reason (this_frame
,
1992 &this_frame
->prologue_cache
);
1994 if (this_frame
->stop_reason
!= UNWIND_NO_REASON
)
1998 enum unwind_stop_reason reason
= this_frame
->stop_reason
;
2000 fprintf_unfiltered (gdb_stdlog
, "-> ");
2001 fprint_frame (gdb_stdlog
, NULL
);
2002 fprintf_unfiltered (gdb_stdlog
, " // %s }\n",
2003 frame_stop_reason_symbol_string (reason
));
2008 /* Check that this frame's ID isn't inner to (younger, below, next)
2009 the next frame. This happens when a frame unwind goes backwards.
2010 This check is valid only if this frame and the next frame are NORMAL.
2011 See the comment at frame_id_inner for details. */
2012 if (get_frame_type (this_frame
) == NORMAL_FRAME
2013 && this_frame
->next
->unwind
->type
== NORMAL_FRAME
2014 && frame_id_inner (get_frame_arch (this_frame
->next
),
2015 get_frame_id (this_frame
),
2016 get_frame_id (this_frame
->next
)))
2018 CORE_ADDR this_pc_in_block
;
2019 struct minimal_symbol
*morestack_msym
;
2020 const char *morestack_name
= NULL
;
2022 /* gcc -fsplit-stack __morestack can continue the stack anywhere. */
2023 this_pc_in_block
= get_frame_address_in_block (this_frame
);
2024 morestack_msym
= lookup_minimal_symbol_by_pc (this_pc_in_block
).minsym
;
2026 morestack_name
= MSYMBOL_LINKAGE_NAME (morestack_msym
);
2027 if (!morestack_name
|| strcmp (morestack_name
, "__morestack") != 0)
2031 fprintf_unfiltered (gdb_stdlog
, "-> ");
2032 fprint_frame (gdb_stdlog
, NULL
);
2033 fprintf_unfiltered (gdb_stdlog
,
2034 " // this frame ID is inner }\n");
2036 this_frame
->stop_reason
= UNWIND_INNER_ID
;
2041 /* Check that this and the next frame do not unwind the PC register
2042 to the same memory location. If they do, then even though they
2043 have different frame IDs, the new frame will be bogus; two
2044 functions can't share a register save slot for the PC. This can
2045 happen when the prologue analyzer finds a stack adjustment, but
2048 This check does assume that the "PC register" is roughly a
2049 traditional PC, even if the gdbarch_unwind_pc method adjusts
2050 it (we do not rely on the value, only on the unwound PC being
2051 dependent on this value). A potential improvement would be
2052 to have the frame prev_pc method and the gdbarch unwind_pc
2053 method set the same lval and location information as
2054 frame_register_unwind. */
2055 if (this_frame
->level
> 0
2056 && gdbarch_pc_regnum (gdbarch
) >= 0
2057 && get_frame_type (this_frame
) == NORMAL_FRAME
2058 && (get_frame_type (this_frame
->next
) == NORMAL_FRAME
2059 || get_frame_type (this_frame
->next
) == INLINE_FRAME
))
2061 int optimized
, realnum
, nrealnum
;
2062 enum lval_type lval
, nlval
;
2063 CORE_ADDR addr
, naddr
;
2065 frame_register_unwind_location (this_frame
,
2066 gdbarch_pc_regnum (gdbarch
),
2067 &optimized
, &lval
, &addr
, &realnum
);
2068 frame_register_unwind_location (get_next_frame (this_frame
),
2069 gdbarch_pc_regnum (gdbarch
),
2070 &optimized
, &nlval
, &naddr
, &nrealnum
);
2072 if ((lval
== lval_memory
&& lval
== nlval
&& addr
== naddr
)
2073 || (lval
== lval_register
&& lval
== nlval
&& realnum
== nrealnum
))
2077 fprintf_unfiltered (gdb_stdlog
, "-> ");
2078 fprint_frame (gdb_stdlog
, NULL
);
2079 fprintf_unfiltered (gdb_stdlog
, " // no saved PC }\n");
2082 this_frame
->stop_reason
= UNWIND_NO_SAVED_PC
;
2083 this_frame
->prev
= NULL
;
2088 return get_prev_frame_if_no_cycle (this_frame
);
2091 /* Return a "struct frame_info" corresponding to the frame that called
2092 THIS_FRAME. Returns NULL if there is no such frame.
2094 Unlike get_prev_frame, this function always tries to unwind the
2098 get_prev_frame_always (struct frame_info
*this_frame
)
2100 struct frame_info
*prev_frame
= NULL
;
2104 prev_frame
= get_prev_frame_always_1 (this_frame
);
2106 CATCH (ex
, RETURN_MASK_ERROR
)
2108 if (ex
.error
== MEMORY_ERROR
)
2110 this_frame
->stop_reason
= UNWIND_MEMORY_ERROR
;
2111 if (ex
.message
!= NULL
)
2116 /* The error needs to live as long as the frame does.
2117 Allocate using stack local STOP_STRING then assign the
2118 pointer to the frame, this allows the STOP_STRING on the
2119 frame to be of type 'const char *'. */
2120 size
= strlen (ex
.message
) + 1;
2121 stop_string
= (char *) frame_obstack_zalloc (size
);
2122 memcpy (stop_string
, ex
.message
, size
);
2123 this_frame
->stop_string
= stop_string
;
2128 throw_exception (ex
);
2135 /* Construct a new "struct frame_info" and link it previous to
2138 static struct frame_info
*
2139 get_prev_frame_raw (struct frame_info
*this_frame
)
2141 struct frame_info
*prev_frame
;
2143 /* Allocate the new frame but do not wire it in to the frame chain.
2144 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
2145 frame->next to pull some fancy tricks (of course such code is, by
2146 definition, recursive). Try to prevent it.
2148 There is no reason to worry about memory leaks, should the
2149 remainder of the function fail. The allocated memory will be
2150 quickly reclaimed when the frame cache is flushed, and the `we've
2151 been here before' check above will stop repeated memory
2152 allocation calls. */
2153 prev_frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
2154 prev_frame
->level
= this_frame
->level
+ 1;
2156 /* For now, assume we don't have frame chains crossing address
2158 prev_frame
->pspace
= this_frame
->pspace
;
2159 prev_frame
->aspace
= this_frame
->aspace
;
2161 /* Don't yet compute ->unwind (and hence ->type). It is computed
2162 on-demand in get_frame_type, frame_register_unwind, and
2165 /* Don't yet compute the frame's ID. It is computed on-demand by
2168 /* The unwound frame ID is validate at the start of this function,
2169 as part of the logic to decide if that frame should be further
2170 unwound, and not here while the prev frame is being created.
2171 Doing this makes it possible for the user to examine a frame that
2172 has an invalid frame ID.
2174 Some very old VAX code noted: [...] For the sake of argument,
2175 suppose that the stack is somewhat trashed (which is one reason
2176 that "info frame" exists). So, return 0 (indicating we don't
2177 know the address of the arglist) if we don't know what frame this
2181 this_frame
->prev
= prev_frame
;
2182 prev_frame
->next
= this_frame
;
2186 fprintf_unfiltered (gdb_stdlog
, "-> ");
2187 fprint_frame (gdb_stdlog
, prev_frame
);
2188 fprintf_unfiltered (gdb_stdlog
, " }\n");
2194 /* Debug routine to print a NULL frame being returned. */
2197 frame_debug_got_null_frame (struct frame_info
*this_frame
,
2202 fprintf_unfiltered (gdb_stdlog
, "{ get_prev_frame (this_frame=");
2203 if (this_frame
!= NULL
)
2204 fprintf_unfiltered (gdb_stdlog
, "%d", this_frame
->level
);
2206 fprintf_unfiltered (gdb_stdlog
, "<NULL>");
2207 fprintf_unfiltered (gdb_stdlog
, ") -> // %s}\n", reason
);
2211 /* Is this (non-sentinel) frame in the "main"() function? */
2214 inside_main_func (struct frame_info
*this_frame
)
2216 struct bound_minimal_symbol msymbol
;
2219 if (symfile_objfile
== 0)
2221 msymbol
= lookup_minimal_symbol (main_name (), NULL
, symfile_objfile
);
2222 if (msymbol
.minsym
== NULL
)
2224 /* Make certain that the code, and not descriptor, address is
2226 maddr
= gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame
),
2227 BMSYMBOL_VALUE_ADDRESS (msymbol
),
2229 return maddr
== get_frame_func (this_frame
);
2232 /* Test whether THIS_FRAME is inside the process entry point function. */
2235 inside_entry_func (struct frame_info
*this_frame
)
2237 CORE_ADDR entry_point
;
2239 if (!entry_point_address_query (&entry_point
))
2242 return get_frame_func (this_frame
) == entry_point
;
2245 /* Return a structure containing various interesting information about
2246 the frame that called THIS_FRAME. Returns NULL if there is entier
2247 no such frame or the frame fails any of a set of target-independent
2248 condition that should terminate the frame chain (e.g., as unwinding
2251 This function should not contain target-dependent tests, such as
2252 checking whether the program-counter is zero. */
2255 get_prev_frame (struct frame_info
*this_frame
)
2260 /* There is always a frame. If this assertion fails, suspect that
2261 something should be calling get_selected_frame() or
2262 get_current_frame(). */
2263 gdb_assert (this_frame
!= NULL
);
2265 /* If this_frame is the current frame, then compute and stash
2266 its frame id prior to fetching and computing the frame id of the
2267 previous frame. Otherwise, the cycle detection code in
2268 get_prev_frame_if_no_cycle() will not work correctly. When
2269 get_frame_id() is called later on, an assertion error will
2270 be triggered in the event of a cycle between the current
2271 frame and its previous frame. */
2272 if (this_frame
->level
== 0)
2273 get_frame_id (this_frame
);
2275 frame_pc_p
= get_frame_pc_if_available (this_frame
, &frame_pc
);
2277 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
2278 sense to stop unwinding at a dummy frame. One place where a dummy
2279 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
2280 pcsqh register (space register for the instruction at the head of the
2281 instruction queue) cannot be written directly; the only way to set it
2282 is to branch to code that is in the target space. In order to implement
2283 frame dummies on HPUX, the called function is made to jump back to where
2284 the inferior was when the user function was called. If gdb was inside
2285 the main function when we created the dummy frame, the dummy frame will
2286 point inside the main function. */
2287 if (this_frame
->level
>= 0
2288 && get_frame_type (this_frame
) == NORMAL_FRAME
2289 && !backtrace_past_main
2291 && inside_main_func (this_frame
))
2292 /* Don't unwind past main(). Note, this is done _before_ the
2293 frame has been marked as previously unwound. That way if the
2294 user later decides to enable unwinds past main(), that will
2295 automatically happen. */
2297 frame_debug_got_null_frame (this_frame
, "inside main func");
2301 /* If the user's backtrace limit has been exceeded, stop. We must
2302 add two to the current level; one of those accounts for backtrace_limit
2303 being 1-based and the level being 0-based, and the other accounts for
2304 the level of the new frame instead of the level of the current
2306 if (this_frame
->level
+ 2 > backtrace_limit
)
2308 frame_debug_got_null_frame (this_frame
, "backtrace limit exceeded");
2312 /* If we're already inside the entry function for the main objfile,
2313 then it isn't valid. Don't apply this test to a dummy frame -
2314 dummy frame PCs typically land in the entry func. Don't apply
2315 this test to the sentinel frame. Sentinel frames should always
2316 be allowed to unwind. */
2317 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
2318 wasn't checking for "main" in the minimal symbols. With that
2319 fixed asm-source tests now stop in "main" instead of halting the
2320 backtrace in weird and wonderful ways somewhere inside the entry
2321 file. Suspect that tests for inside the entry file/func were
2322 added to work around that (now fixed) case. */
2323 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
2324 suggested having the inside_entry_func test use the
2325 inside_main_func() msymbol trick (along with entry_point_address()
2326 I guess) to determine the address range of the start function.
2327 That should provide a far better stopper than the current
2329 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
2330 applied tail-call optimizations to main so that a function called
2331 from main returns directly to the caller of main. Since we don't
2332 stop at main, we should at least stop at the entry point of the
2334 if (this_frame
->level
>= 0
2335 && get_frame_type (this_frame
) == NORMAL_FRAME
2336 && !backtrace_past_entry
2338 && inside_entry_func (this_frame
))
2340 frame_debug_got_null_frame (this_frame
, "inside entry func");
2344 /* Assume that the only way to get a zero PC is through something
2345 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
2346 will never unwind a zero PC. */
2347 if (this_frame
->level
> 0
2348 && (get_frame_type (this_frame
) == NORMAL_FRAME
2349 || get_frame_type (this_frame
) == INLINE_FRAME
)
2350 && get_frame_type (get_next_frame (this_frame
)) == NORMAL_FRAME
2351 && frame_pc_p
&& frame_pc
== 0)
2353 frame_debug_got_null_frame (this_frame
, "zero PC");
2357 return get_prev_frame_always (this_frame
);
2361 get_prev_frame_id_by_id (struct frame_id id
)
2363 struct frame_id prev_id
;
2364 struct frame_info
*frame
;
2366 frame
= frame_find_by_id (id
);
2369 prev_id
= get_frame_id (get_prev_frame (frame
));
2371 prev_id
= null_frame_id
;
2377 get_frame_pc (struct frame_info
*frame
)
2379 gdb_assert (frame
->next
!= NULL
);
2380 return frame_unwind_pc (frame
->next
);
2384 get_frame_pc_if_available (struct frame_info
*frame
, CORE_ADDR
*pc
)
2387 gdb_assert (frame
->next
!= NULL
);
2391 *pc
= frame_unwind_pc (frame
->next
);
2393 CATCH (ex
, RETURN_MASK_ERROR
)
2395 if (ex
.error
== NOT_AVAILABLE_ERROR
)
2398 throw_exception (ex
);
2405 /* Return an address that falls within THIS_FRAME's code block. */
2408 get_frame_address_in_block (struct frame_info
*this_frame
)
2410 /* A draft address. */
2411 CORE_ADDR pc
= get_frame_pc (this_frame
);
2413 struct frame_info
*next_frame
= this_frame
->next
;
2415 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
2416 Normally the resume address is inside the body of the function
2417 associated with THIS_FRAME, but there is a special case: when
2418 calling a function which the compiler knows will never return
2419 (for instance abort), the call may be the very last instruction
2420 in the calling function. The resume address will point after the
2421 call and may be at the beginning of a different function
2424 If THIS_FRAME is a signal frame or dummy frame, then we should
2425 not adjust the unwound PC. For a dummy frame, GDB pushed the
2426 resume address manually onto the stack. For a signal frame, the
2427 OS may have pushed the resume address manually and invoked the
2428 handler (e.g. GNU/Linux), or invoked the trampoline which called
2429 the signal handler - but in either case the signal handler is
2430 expected to return to the trampoline. So in both of these
2431 cases we know that the resume address is executable and
2432 related. So we only need to adjust the PC if THIS_FRAME
2433 is a normal function.
2435 If the program has been interrupted while THIS_FRAME is current,
2436 then clearly the resume address is inside the associated
2437 function. There are three kinds of interruption: debugger stop
2438 (next frame will be SENTINEL_FRAME), operating system
2439 signal or exception (next frame will be SIGTRAMP_FRAME),
2440 or debugger-induced function call (next frame will be
2441 DUMMY_FRAME). So we only need to adjust the PC if
2442 NEXT_FRAME is a normal function.
2444 We check the type of NEXT_FRAME first, since it is already
2445 known; frame type is determined by the unwinder, and since
2446 we have THIS_FRAME we've already selected an unwinder for
2449 If the next frame is inlined, we need to keep going until we find
2450 the real function - for instance, if a signal handler is invoked
2451 while in an inlined function, then the code address of the
2452 "calling" normal function should not be adjusted either. */
2454 while (get_frame_type (next_frame
) == INLINE_FRAME
)
2455 next_frame
= next_frame
->next
;
2457 if ((get_frame_type (next_frame
) == NORMAL_FRAME
2458 || get_frame_type (next_frame
) == TAILCALL_FRAME
)
2459 && (get_frame_type (this_frame
) == NORMAL_FRAME
2460 || get_frame_type (this_frame
) == TAILCALL_FRAME
2461 || get_frame_type (this_frame
) == INLINE_FRAME
))
2468 get_frame_address_in_block_if_available (struct frame_info
*this_frame
,
2474 *pc
= get_frame_address_in_block (this_frame
);
2476 CATCH (ex
, RETURN_MASK_ERROR
)
2478 if (ex
.error
== NOT_AVAILABLE_ERROR
)
2480 throw_exception (ex
);
2488 find_frame_sal (frame_info
*frame
)
2490 struct frame_info
*next_frame
;
2494 /* If the next frame represents an inlined function call, this frame's
2495 sal is the "call site" of that inlined function, which can not
2496 be inferred from get_frame_pc. */
2497 next_frame
= get_next_frame (frame
);
2498 if (frame_inlined_callees (frame
) > 0)
2503 sym
= get_frame_function (next_frame
);
2505 sym
= inline_skipped_symbol (inferior_ptid
);
2507 /* If frame is inline, it certainly has symbols. */
2510 symtab_and_line sal
;
2511 if (SYMBOL_LINE (sym
) != 0)
2513 sal
.symtab
= symbol_symtab (sym
);
2514 sal
.line
= SYMBOL_LINE (sym
);
2517 /* If the symbol does not have a location, we don't know where
2518 the call site is. Do not pretend to. This is jarring, but
2519 we can't do much better. */
2520 sal
.pc
= get_frame_pc (frame
);
2522 sal
.pspace
= get_frame_program_space (frame
);
2526 /* If FRAME is not the innermost frame, that normally means that
2527 FRAME->pc points at the return instruction (which is *after* the
2528 call instruction), and we want to get the line containing the
2529 call (because the call is where the user thinks the program is).
2530 However, if the next frame is either a SIGTRAMP_FRAME or a
2531 DUMMY_FRAME, then the next frame will contain a saved interrupt
2532 PC and such a PC indicates the current (rather than next)
2533 instruction/line, consequently, for such cases, want to get the
2534 line containing fi->pc. */
2535 if (!get_frame_pc_if_available (frame
, &pc
))
2538 notcurrent
= (pc
!= get_frame_address_in_block (frame
));
2539 return find_pc_line (pc
, notcurrent
);
2542 /* Per "frame.h", return the ``address'' of the frame. Code should
2543 really be using get_frame_id(). */
2545 get_frame_base (struct frame_info
*fi
)
2547 return get_frame_id (fi
).stack_addr
;
2550 /* High-level offsets into the frame. Used by the debug info. */
2553 get_frame_base_address (struct frame_info
*fi
)
2555 if (get_frame_type (fi
) != NORMAL_FRAME
)
2557 if (fi
->base
== NULL
)
2558 fi
->base
= frame_base_find_by_frame (fi
);
2559 /* Sneaky: If the low-level unwind and high-level base code share a
2560 common unwinder, let them share the prologue cache. */
2561 if (fi
->base
->unwind
== fi
->unwind
)
2562 return fi
->base
->this_base (fi
, &fi
->prologue_cache
);
2563 return fi
->base
->this_base (fi
, &fi
->base_cache
);
2567 get_frame_locals_address (struct frame_info
*fi
)
2569 if (get_frame_type (fi
) != NORMAL_FRAME
)
2571 /* If there isn't a frame address method, find it. */
2572 if (fi
->base
== NULL
)
2573 fi
->base
= frame_base_find_by_frame (fi
);
2574 /* Sneaky: If the low-level unwind and high-level base code share a
2575 common unwinder, let them share the prologue cache. */
2576 if (fi
->base
->unwind
== fi
->unwind
)
2577 return fi
->base
->this_locals (fi
, &fi
->prologue_cache
);
2578 return fi
->base
->this_locals (fi
, &fi
->base_cache
);
2582 get_frame_args_address (struct frame_info
*fi
)
2584 if (get_frame_type (fi
) != NORMAL_FRAME
)
2586 /* If there isn't a frame address method, find it. */
2587 if (fi
->base
== NULL
)
2588 fi
->base
= frame_base_find_by_frame (fi
);
2589 /* Sneaky: If the low-level unwind and high-level base code share a
2590 common unwinder, let them share the prologue cache. */
2591 if (fi
->base
->unwind
== fi
->unwind
)
2592 return fi
->base
->this_args (fi
, &fi
->prologue_cache
);
2593 return fi
->base
->this_args (fi
, &fi
->base_cache
);
2596 /* Return true if the frame unwinder for frame FI is UNWINDER; false
2600 frame_unwinder_is (struct frame_info
*fi
, const struct frame_unwind
*unwinder
)
2602 if (fi
->unwind
== NULL
)
2603 frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
2604 return fi
->unwind
== unwinder
;
2607 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
2608 or -1 for a NULL frame. */
2611 frame_relative_level (struct frame_info
*fi
)
2620 get_frame_type (struct frame_info
*frame
)
2622 if (frame
->unwind
== NULL
)
2623 /* Initialize the frame's unwinder because that's what
2624 provides the frame's type. */
2625 frame_unwind_find_by_frame (frame
, &frame
->prologue_cache
);
2626 return frame
->unwind
->type
;
2629 struct program_space
*
2630 get_frame_program_space (struct frame_info
*frame
)
2632 return frame
->pspace
;
2635 struct program_space
*
2636 frame_unwind_program_space (struct frame_info
*this_frame
)
2638 gdb_assert (this_frame
);
2640 /* This is really a placeholder to keep the API consistent --- we
2641 assume for now that we don't have frame chains crossing
2643 return this_frame
->pspace
;
2646 struct address_space
*
2647 get_frame_address_space (struct frame_info
*frame
)
2649 return frame
->aspace
;
2652 /* Memory access methods. */
2655 get_frame_memory (struct frame_info
*this_frame
, CORE_ADDR addr
,
2656 gdb_byte
*buf
, int len
)
2658 read_memory (addr
, buf
, len
);
2662 get_frame_memory_signed (struct frame_info
*this_frame
, CORE_ADDR addr
,
2665 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2666 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
2668 return read_memory_integer (addr
, len
, byte_order
);
2672 get_frame_memory_unsigned (struct frame_info
*this_frame
, CORE_ADDR addr
,
2675 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2676 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
2678 return read_memory_unsigned_integer (addr
, len
, byte_order
);
2682 safe_frame_unwind_memory (struct frame_info
*this_frame
,
2683 CORE_ADDR addr
, gdb_byte
*buf
, int len
)
2685 /* NOTE: target_read_memory returns zero on success! */
2686 return !target_read_memory (addr
, buf
, len
);
2689 /* Architecture methods. */
2692 get_frame_arch (struct frame_info
*this_frame
)
2694 return frame_unwind_arch (this_frame
->next
);
2698 frame_unwind_arch (struct frame_info
*next_frame
)
2700 if (!next_frame
->prev_arch
.p
)
2702 struct gdbarch
*arch
;
2704 if (next_frame
->unwind
== NULL
)
2705 frame_unwind_find_by_frame (next_frame
, &next_frame
->prologue_cache
);
2707 if (next_frame
->unwind
->prev_arch
!= NULL
)
2708 arch
= next_frame
->unwind
->prev_arch (next_frame
,
2709 &next_frame
->prologue_cache
);
2711 arch
= get_frame_arch (next_frame
);
2713 next_frame
->prev_arch
.arch
= arch
;
2714 next_frame
->prev_arch
.p
= 1;
2716 fprintf_unfiltered (gdb_stdlog
,
2717 "{ frame_unwind_arch (next_frame=%d) -> %s }\n",
2719 gdbarch_bfd_arch_info (arch
)->printable_name
);
2722 return next_frame
->prev_arch
.arch
;
2726 frame_unwind_caller_arch (struct frame_info
*next_frame
)
2728 next_frame
= skip_artificial_frames (next_frame
);
2730 /* We must have a non-artificial frame. The caller is supposed to check
2731 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
2733 gdb_assert (next_frame
!= NULL
);
2735 return frame_unwind_arch (next_frame
);
2738 /* Gets the language of FRAME. */
2741 get_frame_language (struct frame_info
*frame
)
2746 gdb_assert (frame
!= NULL
);
2748 /* We determine the current frame language by looking up its
2749 associated symtab. To retrieve this symtab, we use the frame
2750 PC. However we cannot use the frame PC as is, because it
2751 usually points to the instruction following the "call", which
2752 is sometimes the first instruction of another function. So
2753 we rely on get_frame_address_in_block(), it provides us with
2754 a PC that is guaranteed to be inside the frame's code
2759 pc
= get_frame_address_in_block (frame
);
2762 CATCH (ex
, RETURN_MASK_ERROR
)
2764 if (ex
.error
!= NOT_AVAILABLE_ERROR
)
2765 throw_exception (ex
);
2771 struct compunit_symtab
*cust
= find_pc_compunit_symtab (pc
);
2774 return compunit_language (cust
);
2777 return language_unknown
;
2780 /* Stack pointer methods. */
2783 get_frame_sp (struct frame_info
*this_frame
)
2785 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2787 /* Normality - an architecture that provides a way of obtaining any
2788 frame inner-most address. */
2789 if (gdbarch_unwind_sp_p (gdbarch
))
2790 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
2791 operate on THIS_FRAME now. */
2792 return gdbarch_unwind_sp (gdbarch
, this_frame
->next
);
2793 /* Now things are really are grim. Hope that the value returned by
2794 the gdbarch_sp_regnum register is meaningful. */
2795 if (gdbarch_sp_regnum (gdbarch
) >= 0)
2796 return get_frame_register_unsigned (this_frame
,
2797 gdbarch_sp_regnum (gdbarch
));
2798 internal_error (__FILE__
, __LINE__
, _("Missing unwind SP method"));
2801 /* Return the reason why we can't unwind past FRAME. */
2803 enum unwind_stop_reason
2804 get_frame_unwind_stop_reason (struct frame_info
*frame
)
2806 /* Fill-in STOP_REASON. */
2807 get_prev_frame_always (frame
);
2808 gdb_assert (frame
->prev_p
);
2810 return frame
->stop_reason
;
2813 /* Return a string explaining REASON. */
2816 unwind_stop_reason_to_string (enum unwind_stop_reason reason
)
2820 #define SET(name, description) \
2821 case name: return _(description);
2822 #include "unwind_stop_reasons.def"
2826 internal_error (__FILE__
, __LINE__
,
2827 "Invalid frame stop reason");
2832 frame_stop_reason_string (struct frame_info
*fi
)
2834 gdb_assert (fi
->prev_p
);
2835 gdb_assert (fi
->prev
== NULL
);
2837 /* Return the specific string if we have one. */
2838 if (fi
->stop_string
!= NULL
)
2839 return fi
->stop_string
;
2841 /* Return the generic string if we have nothing better. */
2842 return unwind_stop_reason_to_string (fi
->stop_reason
);
2845 /* Return the enum symbol name of REASON as a string, to use in debug
2849 frame_stop_reason_symbol_string (enum unwind_stop_reason reason
)
2853 #define SET(name, description) \
2854 case name: return #name;
2855 #include "unwind_stop_reasons.def"
2859 internal_error (__FILE__
, __LINE__
,
2860 "Invalid frame stop reason");
2864 /* Clean up after a failed (wrong unwinder) attempt to unwind past
2868 frame_cleanup_after_sniffer (struct frame_info
*frame
)
2870 /* The sniffer should not allocate a prologue cache if it did not
2871 match this frame. */
2872 gdb_assert (frame
->prologue_cache
== NULL
);
2874 /* No sniffer should extend the frame chain; sniff based on what is
2876 gdb_assert (!frame
->prev_p
);
2878 /* The sniffer should not check the frame's ID; that's circular. */
2879 gdb_assert (!frame
->this_id
.p
);
2881 /* Clear cached fields dependent on the unwinder.
2883 The previous PC is independent of the unwinder, but the previous
2884 function is not (see get_frame_address_in_block). */
2885 frame
->prev_func
.p
= 0;
2886 frame
->prev_func
.addr
= 0;
2888 /* Discard the unwinder last, so that we can easily find it if an assertion
2889 in this function triggers. */
2890 frame
->unwind
= NULL
;
2893 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
2894 If sniffing fails, the caller should be sure to call
2895 frame_cleanup_after_sniffer. */
2898 frame_prepare_for_sniffer (struct frame_info
*frame
,
2899 const struct frame_unwind
*unwind
)
2901 gdb_assert (frame
->unwind
== NULL
);
2902 frame
->unwind
= unwind
;
2905 static struct cmd_list_element
*set_backtrace_cmdlist
;
2906 static struct cmd_list_element
*show_backtrace_cmdlist
;
2909 set_backtrace_cmd (const char *args
, int from_tty
)
2911 help_list (set_backtrace_cmdlist
, "set backtrace ", all_commands
,
2916 show_backtrace_cmd (const char *args
, int from_tty
)
2918 cmd_show_list (show_backtrace_cmdlist
, from_tty
, "");
2922 _initialize_frame (void)
2924 obstack_init (&frame_cache_obstack
);
2926 frame_stash_create ();
2928 observer_attach_target_changed (frame_observer_target_changed
);
2930 add_prefix_cmd ("backtrace", class_maintenance
, set_backtrace_cmd
, _("\
2931 Set backtrace specific variables.\n\
2932 Configure backtrace variables such as the backtrace limit"),
2933 &set_backtrace_cmdlist
, "set backtrace ",
2934 0/*allow-unknown*/, &setlist
);
2935 add_prefix_cmd ("backtrace", class_maintenance
, show_backtrace_cmd
, _("\
2936 Show backtrace specific variables\n\
2937 Show backtrace variables such as the backtrace limit"),
2938 &show_backtrace_cmdlist
, "show backtrace ",
2939 0/*allow-unknown*/, &showlist
);
2941 add_setshow_boolean_cmd ("past-main", class_obscure
,
2942 &backtrace_past_main
, _("\
2943 Set whether backtraces should continue past \"main\"."), _("\
2944 Show whether backtraces should continue past \"main\"."), _("\
2945 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
2946 the backtrace at \"main\". Set this variable if you need to see the rest\n\
2947 of the stack trace."),
2949 show_backtrace_past_main
,
2950 &set_backtrace_cmdlist
,
2951 &show_backtrace_cmdlist
);
2953 add_setshow_boolean_cmd ("past-entry", class_obscure
,
2954 &backtrace_past_entry
, _("\
2955 Set whether backtraces should continue past the entry point of a program."),
2957 Show whether backtraces should continue past the entry point of a program."),
2959 Normally there are no callers beyond the entry point of a program, so GDB\n\
2960 will terminate the backtrace there. Set this variable if you need to see\n\
2961 the rest of the stack trace."),
2963 show_backtrace_past_entry
,
2964 &set_backtrace_cmdlist
,
2965 &show_backtrace_cmdlist
);
2967 add_setshow_uinteger_cmd ("limit", class_obscure
,
2968 &backtrace_limit
, _("\
2969 Set an upper bound on the number of backtrace levels."), _("\
2970 Show the upper bound on the number of backtrace levels."), _("\
2971 No more than the specified number of frames can be displayed or examined.\n\
2972 Literal \"unlimited\" or zero means no limit."),
2974 show_backtrace_limit
,
2975 &set_backtrace_cmdlist
,
2976 &show_backtrace_cmdlist
);
2978 /* Debug this files internals. */
2979 add_setshow_zuinteger_cmd ("frame", class_maintenance
, &frame_debug
, _("\
2980 Set frame debugging."), _("\
2981 Show frame debugging."), _("\
2982 When non-zero, frame specific internal debugging is enabled."),
2985 &setdebuglist
, &showdebuglist
);