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 const 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 std::unique_ptr
<struct regcache
> regcache
1024 (new struct regcache (get_frame_arch (this_frame
)));
1026 regcache_save (regcache
.get (), do_frame_register_read
, this_frame
);
1031 frame_pop (struct frame_info
*this_frame
)
1033 struct frame_info
*prev_frame
;
1035 if (get_frame_type (this_frame
) == DUMMY_FRAME
)
1037 /* Popping a dummy frame involves restoring more than just registers.
1038 dummy_frame_pop does all the work. */
1039 dummy_frame_pop (get_frame_id (this_frame
), inferior_ptid
);
1043 /* Ensure that we have a frame to pop to. */
1044 prev_frame
= get_prev_frame_always (this_frame
);
1047 error (_("Cannot pop the initial frame."));
1049 /* Ignore TAILCALL_FRAME type frames, they were executed already before
1050 entering THISFRAME. */
1051 prev_frame
= skip_tailcall_frames (prev_frame
);
1053 if (prev_frame
== NULL
)
1054 error (_("Cannot find the caller frame."));
1056 /* Make a copy of all the register values unwound from this frame.
1057 Save them in a scratch buffer so that there isn't a race between
1058 trying to extract the old values from the current regcache while
1059 at the same time writing new values into that same cache. */
1060 std::unique_ptr
<struct regcache
> scratch
1061 = frame_save_as_regcache (prev_frame
);
1063 /* FIXME: cagney/2003-03-16: It should be possible to tell the
1064 target's register cache that it is about to be hit with a burst
1065 register transfer and that the sequence of register writes should
1066 be batched. The pair target_prepare_to_store() and
1067 target_store_registers() kind of suggest this functionality.
1068 Unfortunately, they don't implement it. Their lack of a formal
1069 definition can lead to targets writing back bogus values
1070 (arguably a bug in the target code mind). */
1071 /* Now copy those saved registers into the current regcache.
1072 Here, regcache_cpy() calls regcache_restore(). */
1073 regcache_cpy (get_current_regcache (), scratch
.get ());
1075 /* We've made right mess of GDB's local state, just discard
1077 reinit_frame_cache ();
1081 frame_register_unwind (struct frame_info
*frame
, int regnum
,
1082 int *optimizedp
, int *unavailablep
,
1083 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
1084 int *realnump
, gdb_byte
*bufferp
)
1086 struct value
*value
;
1088 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1089 that the value proper does not need to be fetched. */
1090 gdb_assert (optimizedp
!= NULL
);
1091 gdb_assert (lvalp
!= NULL
);
1092 gdb_assert (addrp
!= NULL
);
1093 gdb_assert (realnump
!= NULL
);
1094 /* gdb_assert (bufferp != NULL); */
1096 value
= frame_unwind_register_value (frame
, regnum
);
1098 gdb_assert (value
!= NULL
);
1100 *optimizedp
= value_optimized_out (value
);
1101 *unavailablep
= !value_entirely_available (value
);
1102 *lvalp
= VALUE_LVAL (value
);
1103 *addrp
= value_address (value
);
1104 if (*lvalp
== lval_register
)
1105 *realnump
= VALUE_REGNUM (value
);
1111 if (!*optimizedp
&& !*unavailablep
)
1112 memcpy (bufferp
, value_contents_all (value
),
1113 TYPE_LENGTH (value_type (value
)));
1115 memset (bufferp
, 0, TYPE_LENGTH (value_type (value
)));
1118 /* Dispose of the new value. This prevents watchpoints from
1119 trying to watch the saved frame pointer. */
1120 release_value (value
);
1125 frame_register (struct frame_info
*frame
, int regnum
,
1126 int *optimizedp
, int *unavailablep
, enum lval_type
*lvalp
,
1127 CORE_ADDR
*addrp
, int *realnump
, gdb_byte
*bufferp
)
1129 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1130 that the value proper does not need to be fetched. */
1131 gdb_assert (optimizedp
!= NULL
);
1132 gdb_assert (lvalp
!= NULL
);
1133 gdb_assert (addrp
!= NULL
);
1134 gdb_assert (realnump
!= NULL
);
1135 /* gdb_assert (bufferp != NULL); */
1137 /* Obtain the register value by unwinding the register from the next
1138 (more inner frame). */
1139 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
1140 frame_register_unwind (frame
->next
, regnum
, optimizedp
, unavailablep
,
1141 lvalp
, addrp
, realnump
, bufferp
);
1145 frame_unwind_register (struct frame_info
*frame
, int regnum
, gdb_byte
*buf
)
1151 enum lval_type lval
;
1153 frame_register_unwind (frame
, regnum
, &optimized
, &unavailable
,
1154 &lval
, &addr
, &realnum
, buf
);
1157 throw_error (OPTIMIZED_OUT_ERROR
,
1158 _("Register %d was not saved"), regnum
);
1160 throw_error (NOT_AVAILABLE_ERROR
,
1161 _("Register %d is not available"), regnum
);
1165 get_frame_register (struct frame_info
*frame
,
1166 int regnum
, gdb_byte
*buf
)
1168 frame_unwind_register (frame
->next
, regnum
, buf
);
1172 frame_unwind_register_value (struct frame_info
*frame
, int regnum
)
1174 struct gdbarch
*gdbarch
;
1175 struct value
*value
;
1177 gdb_assert (frame
!= NULL
);
1178 gdbarch
= frame_unwind_arch (frame
);
1182 fprintf_unfiltered (gdb_stdlog
,
1183 "{ frame_unwind_register_value "
1184 "(frame=%d,regnum=%d(%s),...) ",
1185 frame
->level
, regnum
,
1186 user_reg_map_regnum_to_name (gdbarch
, regnum
));
1189 /* Find the unwinder. */
1190 if (frame
->unwind
== NULL
)
1191 frame_unwind_find_by_frame (frame
, &frame
->prologue_cache
);
1193 /* Ask this frame to unwind its register. */
1194 value
= frame
->unwind
->prev_register (frame
, &frame
->prologue_cache
, regnum
);
1198 fprintf_unfiltered (gdb_stdlog
, "->");
1199 if (value_optimized_out (value
))
1201 fprintf_unfiltered (gdb_stdlog
, " ");
1202 val_print_optimized_out (value
, gdb_stdlog
);
1206 if (VALUE_LVAL (value
) == lval_register
)
1207 fprintf_unfiltered (gdb_stdlog
, " register=%d",
1208 VALUE_REGNUM (value
));
1209 else if (VALUE_LVAL (value
) == lval_memory
)
1210 fprintf_unfiltered (gdb_stdlog
, " address=%s",
1212 value_address (value
)));
1214 fprintf_unfiltered (gdb_stdlog
, " computed");
1216 if (value_lazy (value
))
1217 fprintf_unfiltered (gdb_stdlog
, " lazy");
1221 const gdb_byte
*buf
= value_contents (value
);
1223 fprintf_unfiltered (gdb_stdlog
, " bytes=");
1224 fprintf_unfiltered (gdb_stdlog
, "[");
1225 for (i
= 0; i
< register_size (gdbarch
, regnum
); i
++)
1226 fprintf_unfiltered (gdb_stdlog
, "%02x", buf
[i
]);
1227 fprintf_unfiltered (gdb_stdlog
, "]");
1231 fprintf_unfiltered (gdb_stdlog
, " }\n");
1238 get_frame_register_value (struct frame_info
*frame
, int regnum
)
1240 return frame_unwind_register_value (frame
->next
, regnum
);
1244 frame_unwind_register_signed (struct frame_info
*frame
, int regnum
)
1246 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
1247 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1248 int size
= register_size (gdbarch
, regnum
);
1249 struct value
*value
= frame_unwind_register_value (frame
, regnum
);
1251 gdb_assert (value
!= NULL
);
1253 if (value_optimized_out (value
))
1255 throw_error (OPTIMIZED_OUT_ERROR
,
1256 _("Register %d was not saved"), regnum
);
1258 if (!value_entirely_available (value
))
1260 throw_error (NOT_AVAILABLE_ERROR
,
1261 _("Register %d is not available"), regnum
);
1264 LONGEST r
= extract_signed_integer (value_contents_all (value
), size
,
1267 release_value (value
);
1273 get_frame_register_signed (struct frame_info
*frame
, int regnum
)
1275 return frame_unwind_register_signed (frame
->next
, regnum
);
1279 frame_unwind_register_unsigned (struct frame_info
*frame
, int regnum
)
1281 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
1282 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1283 int size
= register_size (gdbarch
, regnum
);
1284 struct value
*value
= frame_unwind_register_value (frame
, regnum
);
1286 gdb_assert (value
!= NULL
);
1288 if (value_optimized_out (value
))
1290 throw_error (OPTIMIZED_OUT_ERROR
,
1291 _("Register %d was not saved"), regnum
);
1293 if (!value_entirely_available (value
))
1295 throw_error (NOT_AVAILABLE_ERROR
,
1296 _("Register %d is not available"), regnum
);
1299 ULONGEST r
= extract_unsigned_integer (value_contents_all (value
), size
,
1302 release_value (value
);
1308 get_frame_register_unsigned (struct frame_info
*frame
, int regnum
)
1310 return frame_unwind_register_unsigned (frame
->next
, regnum
);
1314 read_frame_register_unsigned (struct frame_info
*frame
, int regnum
,
1317 struct value
*regval
= get_frame_register_value (frame
, regnum
);
1319 if (!value_optimized_out (regval
)
1320 && value_entirely_available (regval
))
1322 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1323 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1324 int size
= register_size (gdbarch
, VALUE_REGNUM (regval
));
1326 *val
= extract_unsigned_integer (value_contents (regval
), size
, byte_order
);
1334 put_frame_register (struct frame_info
*frame
, int regnum
,
1335 const gdb_byte
*buf
)
1337 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1341 enum lval_type lval
;
1344 frame_register (frame
, regnum
, &optim
, &unavail
,
1345 &lval
, &addr
, &realnum
, NULL
);
1347 error (_("Attempt to assign to a register that was not saved."));
1352 write_memory (addr
, buf
, register_size (gdbarch
, regnum
));
1356 regcache_cooked_write (get_current_regcache (), realnum
, buf
);
1359 error (_("Attempt to assign to an unmodifiable value."));
1363 /* This function is deprecated. Use get_frame_register_value instead,
1364 which provides more accurate information.
1366 Find and return the value of REGNUM for the specified stack frame.
1367 The number of bytes copied is REGISTER_SIZE (REGNUM).
1369 Returns 0 if the register value could not be found. */
1372 deprecated_frame_register_read (struct frame_info
*frame
, int regnum
,
1377 enum lval_type lval
;
1381 frame_register (frame
, regnum
, &optimized
, &unavailable
,
1382 &lval
, &addr
, &realnum
, myaddr
);
1384 return !optimized
&& !unavailable
;
1388 get_frame_register_bytes (struct frame_info
*frame
, int regnum
,
1389 CORE_ADDR offset
, int len
, gdb_byte
*myaddr
,
1390 int *optimizedp
, int *unavailablep
)
1392 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1397 /* Skip registers wholly inside of OFFSET. */
1398 while (offset
>= register_size (gdbarch
, regnum
))
1400 offset
-= register_size (gdbarch
, regnum
);
1404 /* Ensure that we will not read beyond the end of the register file.
1405 This can only ever happen if the debug information is bad. */
1407 numregs
= gdbarch_num_regs (gdbarch
) + gdbarch_num_pseudo_regs (gdbarch
);
1408 for (i
= regnum
; i
< numregs
; i
++)
1410 int thissize
= register_size (gdbarch
, i
);
1413 break; /* This register is not available on this architecture. */
1414 maxsize
+= thissize
;
1417 error (_("Bad debug information detected: "
1418 "Attempt to read %d bytes from registers."), len
);
1420 /* Copy the data. */
1423 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
1428 if (curr_len
== register_size (gdbarch
, regnum
))
1430 enum lval_type lval
;
1434 frame_register (frame
, regnum
, optimizedp
, unavailablep
,
1435 &lval
, &addr
, &realnum
, myaddr
);
1436 if (*optimizedp
|| *unavailablep
)
1441 struct value
*value
= frame_unwind_register_value (frame
->next
,
1443 gdb_assert (value
!= NULL
);
1444 *optimizedp
= value_optimized_out (value
);
1445 *unavailablep
= !value_entirely_available (value
);
1447 if (*optimizedp
|| *unavailablep
)
1449 release_value (value
);
1453 memcpy (myaddr
, value_contents_all (value
) + offset
, curr_len
);
1454 release_value (value
);
1470 put_frame_register_bytes (struct frame_info
*frame
, int regnum
,
1471 CORE_ADDR offset
, int len
, const gdb_byte
*myaddr
)
1473 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1475 /* Skip registers wholly inside of OFFSET. */
1476 while (offset
>= register_size (gdbarch
, regnum
))
1478 offset
-= register_size (gdbarch
, regnum
);
1482 /* Copy the data. */
1485 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
1490 if (curr_len
== register_size (gdbarch
, regnum
))
1492 put_frame_register (frame
, regnum
, myaddr
);
1496 struct value
*value
= frame_unwind_register_value (frame
->next
,
1498 gdb_assert (value
!= NULL
);
1500 memcpy ((char *) value_contents_writeable (value
) + offset
, myaddr
,
1502 put_frame_register (frame
, regnum
, value_contents_raw (value
));
1503 release_value (value
);
1514 /* Create a sentinel frame. */
1516 static struct frame_info
*
1517 create_sentinel_frame (struct program_space
*pspace
, struct regcache
*regcache
)
1519 struct frame_info
*frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1522 frame
->pspace
= pspace
;
1523 frame
->aspace
= regcache
->aspace ();
1524 /* Explicitly initialize the sentinel frame's cache. Provide it
1525 with the underlying regcache. In the future additional
1526 information, such as the frame's thread will be added. */
1527 frame
->prologue_cache
= sentinel_frame_cache (regcache
);
1528 /* For the moment there is only one sentinel frame implementation. */
1529 frame
->unwind
= &sentinel_frame_unwind
;
1530 /* Link this frame back to itself. The frame is self referential
1531 (the unwound PC is the same as the pc), so make it so. */
1532 frame
->next
= frame
;
1533 /* The sentinel frame has a special ID. */
1534 frame
->this_id
.p
= 1;
1535 frame
->this_id
.value
= sentinel_frame_id
;
1538 fprintf_unfiltered (gdb_stdlog
, "{ create_sentinel_frame (...) -> ");
1539 fprint_frame (gdb_stdlog
, frame
);
1540 fprintf_unfiltered (gdb_stdlog
, " }\n");
1545 /* Cache for frame addresses already read by gdb. Valid only while
1546 inferior is stopped. Control variables for the frame cache should
1547 be local to this module. */
1549 static struct obstack frame_cache_obstack
;
1552 frame_obstack_zalloc (unsigned long size
)
1554 void *data
= obstack_alloc (&frame_cache_obstack
, size
);
1556 memset (data
, 0, size
);
1560 static struct frame_info
*get_prev_frame_always_1 (struct frame_info
*this_frame
);
1563 get_current_frame (void)
1565 struct frame_info
*current_frame
;
1567 /* First check, and report, the lack of registers. Having GDB
1568 report "No stack!" or "No memory" when the target doesn't even
1569 have registers is very confusing. Besides, "printcmd.exp"
1570 explicitly checks that ``print $pc'' with no registers prints "No
1572 if (!target_has_registers
)
1573 error (_("No registers."));
1574 if (!target_has_stack
)
1575 error (_("No stack."));
1576 if (!target_has_memory
)
1577 error (_("No memory."));
1578 /* Traceframes are effectively a substitute for the live inferior. */
1579 if (get_traceframe_number () < 0)
1580 validate_registers_access ();
1582 if (sentinel_frame
== NULL
)
1584 create_sentinel_frame (current_program_space
, get_current_regcache ());
1586 /* Set the current frame before computing the frame id, to avoid
1587 recursion inside compute_frame_id, in case the frame's
1588 unwinder decides to do a symbol lookup (which depends on the
1589 selected frame's block).
1591 This call must always succeed. In particular, nothing inside
1592 get_prev_frame_always_1 should try to unwind from the
1593 sentinel frame, because that could fail/throw, and we always
1594 want to leave with the current frame created and linked in --
1595 we should never end up with the sentinel frame as outermost
1597 current_frame
= get_prev_frame_always_1 (sentinel_frame
);
1598 gdb_assert (current_frame
!= NULL
);
1600 return current_frame
;
1603 /* The "selected" stack frame is used by default for local and arg
1604 access. May be zero, for no selected frame. */
1606 static struct frame_info
*selected_frame
;
1609 has_stack_frames (void)
1611 if (!target_has_registers
|| !target_has_stack
|| !target_has_memory
)
1614 /* Traceframes are effectively a substitute for the live inferior. */
1615 if (get_traceframe_number () < 0)
1617 /* No current inferior, no frame. */
1618 if (ptid_equal (inferior_ptid
, null_ptid
))
1621 /* Don't try to read from a dead thread. */
1622 if (is_exited (inferior_ptid
))
1625 /* ... or from a spinning thread. */
1626 if (is_executing (inferior_ptid
))
1633 /* Return the selected frame. Always non-NULL (unless there isn't an
1634 inferior sufficient for creating a frame) in which case an error is
1638 get_selected_frame (const char *message
)
1640 if (selected_frame
== NULL
)
1642 if (message
!= NULL
&& !has_stack_frames ())
1643 error (("%s"), message
);
1644 /* Hey! Don't trust this. It should really be re-finding the
1645 last selected frame of the currently selected thread. This,
1646 though, is better than nothing. */
1647 select_frame (get_current_frame ());
1649 /* There is always a frame. */
1650 gdb_assert (selected_frame
!= NULL
);
1651 return selected_frame
;
1654 /* If there is a selected frame, return it. Otherwise, return NULL. */
1657 get_selected_frame_if_set (void)
1659 return selected_frame
;
1662 /* This is a variant of get_selected_frame() which can be called when
1663 the inferior does not have a frame; in that case it will return
1664 NULL instead of calling error(). */
1667 deprecated_safe_get_selected_frame (void)
1669 if (!has_stack_frames ())
1671 return get_selected_frame (NULL
);
1674 /* Select frame FI (or NULL - to invalidate the current frame). */
1677 select_frame (struct frame_info
*fi
)
1679 selected_frame
= fi
;
1680 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
1681 frame is being invalidated. */
1683 /* FIXME: kseitz/2002-08-28: It would be nice to call
1684 selected_frame_level_changed_event() right here, but due to limitations
1685 in the current interfaces, we would end up flooding UIs with events
1686 because select_frame() is used extensively internally.
1688 Once we have frame-parameterized frame (and frame-related) commands,
1689 the event notification can be moved here, since this function will only
1690 be called when the user's selected frame is being changed. */
1692 /* Ensure that symbols for this frame are read in. Also, determine the
1693 source language of this frame, and switch to it if desired. */
1698 /* We retrieve the frame's symtab by using the frame PC.
1699 However we cannot use the frame PC as-is, because it usually
1700 points to the instruction following the "call", which is
1701 sometimes the first instruction of another function. So we
1702 rely on get_frame_address_in_block() which provides us with a
1703 PC which is guaranteed to be inside the frame's code
1705 if (get_frame_address_in_block_if_available (fi
, &pc
))
1707 struct compunit_symtab
*cust
= find_pc_compunit_symtab (pc
);
1710 && compunit_language (cust
) != current_language
->la_language
1711 && compunit_language (cust
) != language_unknown
1712 && language_mode
== language_mode_auto
)
1713 set_language (compunit_language (cust
));
1718 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
1719 Always returns a non-NULL value. */
1722 create_new_frame (CORE_ADDR addr
, CORE_ADDR pc
)
1724 struct frame_info
*fi
;
1728 fprintf_unfiltered (gdb_stdlog
,
1729 "{ create_new_frame (addr=%s, pc=%s) ",
1730 hex_string (addr
), hex_string (pc
));
1733 fi
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1735 fi
->next
= create_sentinel_frame (current_program_space
,
1736 get_current_regcache ());
1738 /* Set/update this frame's cached PC value, found in the next frame.
1739 Do this before looking for this frame's unwinder. A sniffer is
1740 very likely to read this, and the corresponding unwinder is
1741 entitled to rely that the PC doesn't magically change. */
1742 fi
->next
->prev_pc
.value
= pc
;
1743 fi
->next
->prev_pc
.status
= CC_VALUE
;
1745 /* We currently assume that frame chain's can't cross spaces. */
1746 fi
->pspace
= fi
->next
->pspace
;
1747 fi
->aspace
= fi
->next
->aspace
;
1749 /* Select/initialize both the unwind function and the frame's type
1751 frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
1754 fi
->this_id
.value
= frame_id_build (addr
, pc
);
1758 fprintf_unfiltered (gdb_stdlog
, "-> ");
1759 fprint_frame (gdb_stdlog
, fi
);
1760 fprintf_unfiltered (gdb_stdlog
, " }\n");
1766 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
1767 innermost frame). Be careful to not fall off the bottom of the
1768 frame chain and onto the sentinel frame. */
1771 get_next_frame (struct frame_info
*this_frame
)
1773 if (this_frame
->level
> 0)
1774 return this_frame
->next
;
1779 /* Return the frame that THIS_FRAME calls. If THIS_FRAME is the
1780 innermost (i.e. current) frame, return the sentinel frame. Thus,
1781 unlike get_next_frame(), NULL will never be returned. */
1784 get_next_frame_sentinel_okay (struct frame_info
*this_frame
)
1786 gdb_assert (this_frame
!= NULL
);
1788 /* Note that, due to the manner in which the sentinel frame is
1789 constructed, this_frame->next still works even when this_frame
1790 is the sentinel frame. But we disallow it here anyway because
1791 calling get_next_frame_sentinel_okay() on the sentinel frame
1792 is likely a coding error. */
1793 gdb_assert (this_frame
!= sentinel_frame
);
1795 return this_frame
->next
;
1798 /* Observer for the target_changed event. */
1801 frame_observer_target_changed (struct target_ops
*target
)
1803 reinit_frame_cache ();
1806 /* Flush the entire frame cache. */
1809 reinit_frame_cache (void)
1811 struct frame_info
*fi
;
1813 /* Tear down all frame caches. */
1814 for (fi
= sentinel_frame
; fi
!= NULL
; fi
= fi
->prev
)
1816 if (fi
->prologue_cache
&& fi
->unwind
->dealloc_cache
)
1817 fi
->unwind
->dealloc_cache (fi
, fi
->prologue_cache
);
1818 if (fi
->base_cache
&& fi
->base
->unwind
->dealloc_cache
)
1819 fi
->base
->unwind
->dealloc_cache (fi
, fi
->base_cache
);
1822 /* Since we can't really be sure what the first object allocated was. */
1823 obstack_free (&frame_cache_obstack
, 0);
1824 obstack_init (&frame_cache_obstack
);
1826 if (sentinel_frame
!= NULL
)
1827 annotate_frames_invalid ();
1829 sentinel_frame
= NULL
; /* Invalidate cache */
1830 select_frame (NULL
);
1831 frame_stash_invalidate ();
1833 fprintf_unfiltered (gdb_stdlog
, "{ reinit_frame_cache () }\n");
1836 /* Find where a register is saved (in memory or another register).
1837 The result of frame_register_unwind is just where it is saved
1838 relative to this particular frame. */
1841 frame_register_unwind_location (struct frame_info
*this_frame
, int regnum
,
1842 int *optimizedp
, enum lval_type
*lvalp
,
1843 CORE_ADDR
*addrp
, int *realnump
)
1845 gdb_assert (this_frame
== NULL
|| this_frame
->level
>= 0);
1847 while (this_frame
!= NULL
)
1851 frame_register_unwind (this_frame
, regnum
, optimizedp
, &unavailable
,
1852 lvalp
, addrp
, realnump
, NULL
);
1857 if (*lvalp
!= lval_register
)
1861 this_frame
= get_next_frame (this_frame
);
1865 /* Called during frame unwinding to remove a previous frame pointer from a
1866 frame passed in ARG. */
1869 remove_prev_frame (void *arg
)
1871 struct frame_info
*this_frame
, *prev_frame
;
1873 this_frame
= (struct frame_info
*) arg
;
1874 prev_frame
= this_frame
->prev
;
1875 gdb_assert (prev_frame
!= NULL
);
1877 prev_frame
->next
= NULL
;
1878 this_frame
->prev
= NULL
;
1881 /* Get the previous raw frame, and check that it is not identical to
1882 same other frame frame already in the chain. If it is, there is
1883 most likely a stack cycle, so we discard it, and mark THIS_FRAME as
1884 outermost, with UNWIND_SAME_ID stop reason. Unlike the other
1885 validity tests, that compare THIS_FRAME and the next frame, we do
1886 this right after creating the previous frame, to avoid ever ending
1887 up with two frames with the same id in the frame chain. */
1889 static struct frame_info
*
1890 get_prev_frame_if_no_cycle (struct frame_info
*this_frame
)
1892 struct frame_info
*prev_frame
;
1893 struct cleanup
*prev_frame_cleanup
;
1895 prev_frame
= get_prev_frame_raw (this_frame
);
1897 /* Don't compute the frame id of the current frame yet. Unwinding
1898 the sentinel frame can fail (e.g., if the thread is gone and we
1899 can't thus read its registers). If we let the cycle detection
1900 code below try to compute a frame ID, then an error thrown from
1901 within the frame ID computation would result in the sentinel
1902 frame as outermost frame, which is bogus. Instead, we'll compute
1903 the current frame's ID lazily in get_frame_id. Note that there's
1904 no point in doing cycle detection when there's only one frame, so
1905 nothing is lost here. */
1906 if (prev_frame
->level
== 0)
1909 /* The cleanup will remove the previous frame that get_prev_frame_raw
1910 linked onto THIS_FRAME. */
1911 prev_frame_cleanup
= make_cleanup (remove_prev_frame
, this_frame
);
1913 compute_frame_id (prev_frame
);
1914 if (!frame_stash_add (prev_frame
))
1916 /* Another frame with the same id was already in the stash. We just
1917 detected a cycle. */
1920 fprintf_unfiltered (gdb_stdlog
, "-> ");
1921 fprint_frame (gdb_stdlog
, NULL
);
1922 fprintf_unfiltered (gdb_stdlog
, " // this frame has same ID }\n");
1924 this_frame
->stop_reason
= UNWIND_SAME_ID
;
1926 prev_frame
->next
= NULL
;
1927 this_frame
->prev
= NULL
;
1931 discard_cleanups (prev_frame_cleanup
);
1935 /* Helper function for get_prev_frame_always, this is called inside a
1936 TRY_CATCH block. Return the frame that called THIS_FRAME or NULL if
1937 there is no such frame. This may throw an exception. */
1939 static struct frame_info
*
1940 get_prev_frame_always_1 (struct frame_info
*this_frame
)
1942 struct gdbarch
*gdbarch
;
1944 gdb_assert (this_frame
!= NULL
);
1945 gdbarch
= get_frame_arch (this_frame
);
1949 fprintf_unfiltered (gdb_stdlog
, "{ get_prev_frame_always (this_frame=");
1950 if (this_frame
!= NULL
)
1951 fprintf_unfiltered (gdb_stdlog
, "%d", this_frame
->level
);
1953 fprintf_unfiltered (gdb_stdlog
, "<NULL>");
1954 fprintf_unfiltered (gdb_stdlog
, ") ");
1957 /* Only try to do the unwind once. */
1958 if (this_frame
->prev_p
)
1962 fprintf_unfiltered (gdb_stdlog
, "-> ");
1963 fprint_frame (gdb_stdlog
, this_frame
->prev
);
1964 fprintf_unfiltered (gdb_stdlog
, " // cached \n");
1966 return this_frame
->prev
;
1969 /* If the frame unwinder hasn't been selected yet, we must do so
1970 before setting prev_p; otherwise the check for misbehaved
1971 sniffers will think that this frame's sniffer tried to unwind
1972 further (see frame_cleanup_after_sniffer). */
1973 if (this_frame
->unwind
== NULL
)
1974 frame_unwind_find_by_frame (this_frame
, &this_frame
->prologue_cache
);
1976 this_frame
->prev_p
= 1;
1977 this_frame
->stop_reason
= UNWIND_NO_REASON
;
1979 /* If we are unwinding from an inline frame, all of the below tests
1980 were already performed when we unwound from the next non-inline
1981 frame. We must skip them, since we can not get THIS_FRAME's ID
1982 until we have unwound all the way down to the previous non-inline
1984 if (get_frame_type (this_frame
) == INLINE_FRAME
)
1985 return get_prev_frame_if_no_cycle (this_frame
);
1987 /* Check that this frame is unwindable. If it isn't, don't try to
1988 unwind to the prev frame. */
1989 this_frame
->stop_reason
1990 = this_frame
->unwind
->stop_reason (this_frame
,
1991 &this_frame
->prologue_cache
);
1993 if (this_frame
->stop_reason
!= UNWIND_NO_REASON
)
1997 enum unwind_stop_reason reason
= this_frame
->stop_reason
;
1999 fprintf_unfiltered (gdb_stdlog
, "-> ");
2000 fprint_frame (gdb_stdlog
, NULL
);
2001 fprintf_unfiltered (gdb_stdlog
, " // %s }\n",
2002 frame_stop_reason_symbol_string (reason
));
2007 /* Check that this frame's ID isn't inner to (younger, below, next)
2008 the next frame. This happens when a frame unwind goes backwards.
2009 This check is valid only if this frame and the next frame are NORMAL.
2010 See the comment at frame_id_inner for details. */
2011 if (get_frame_type (this_frame
) == NORMAL_FRAME
2012 && this_frame
->next
->unwind
->type
== NORMAL_FRAME
2013 && frame_id_inner (get_frame_arch (this_frame
->next
),
2014 get_frame_id (this_frame
),
2015 get_frame_id (this_frame
->next
)))
2017 CORE_ADDR this_pc_in_block
;
2018 struct minimal_symbol
*morestack_msym
;
2019 const char *morestack_name
= NULL
;
2021 /* gcc -fsplit-stack __morestack can continue the stack anywhere. */
2022 this_pc_in_block
= get_frame_address_in_block (this_frame
);
2023 morestack_msym
= lookup_minimal_symbol_by_pc (this_pc_in_block
).minsym
;
2025 morestack_name
= MSYMBOL_LINKAGE_NAME (morestack_msym
);
2026 if (!morestack_name
|| strcmp (morestack_name
, "__morestack") != 0)
2030 fprintf_unfiltered (gdb_stdlog
, "-> ");
2031 fprint_frame (gdb_stdlog
, NULL
);
2032 fprintf_unfiltered (gdb_stdlog
,
2033 " // this frame ID is inner }\n");
2035 this_frame
->stop_reason
= UNWIND_INNER_ID
;
2040 /* Check that this and the next frame do not unwind the PC register
2041 to the same memory location. If they do, then even though they
2042 have different frame IDs, the new frame will be bogus; two
2043 functions can't share a register save slot for the PC. This can
2044 happen when the prologue analyzer finds a stack adjustment, but
2047 This check does assume that the "PC register" is roughly a
2048 traditional PC, even if the gdbarch_unwind_pc method adjusts
2049 it (we do not rely on the value, only on the unwound PC being
2050 dependent on this value). A potential improvement would be
2051 to have the frame prev_pc method and the gdbarch unwind_pc
2052 method set the same lval and location information as
2053 frame_register_unwind. */
2054 if (this_frame
->level
> 0
2055 && gdbarch_pc_regnum (gdbarch
) >= 0
2056 && get_frame_type (this_frame
) == NORMAL_FRAME
2057 && (get_frame_type (this_frame
->next
) == NORMAL_FRAME
2058 || get_frame_type (this_frame
->next
) == INLINE_FRAME
))
2060 int optimized
, realnum
, nrealnum
;
2061 enum lval_type lval
, nlval
;
2062 CORE_ADDR addr
, naddr
;
2064 frame_register_unwind_location (this_frame
,
2065 gdbarch_pc_regnum (gdbarch
),
2066 &optimized
, &lval
, &addr
, &realnum
);
2067 frame_register_unwind_location (get_next_frame (this_frame
),
2068 gdbarch_pc_regnum (gdbarch
),
2069 &optimized
, &nlval
, &naddr
, &nrealnum
);
2071 if ((lval
== lval_memory
&& lval
== nlval
&& addr
== naddr
)
2072 || (lval
== lval_register
&& lval
== nlval
&& realnum
== nrealnum
))
2076 fprintf_unfiltered (gdb_stdlog
, "-> ");
2077 fprint_frame (gdb_stdlog
, NULL
);
2078 fprintf_unfiltered (gdb_stdlog
, " // no saved PC }\n");
2081 this_frame
->stop_reason
= UNWIND_NO_SAVED_PC
;
2082 this_frame
->prev
= NULL
;
2087 return get_prev_frame_if_no_cycle (this_frame
);
2090 /* Return a "struct frame_info" corresponding to the frame that called
2091 THIS_FRAME. Returns NULL if there is no such frame.
2093 Unlike get_prev_frame, this function always tries to unwind the
2097 get_prev_frame_always (struct frame_info
*this_frame
)
2099 struct frame_info
*prev_frame
= NULL
;
2103 prev_frame
= get_prev_frame_always_1 (this_frame
);
2105 CATCH (ex
, RETURN_MASK_ERROR
)
2107 if (ex
.error
== MEMORY_ERROR
)
2109 this_frame
->stop_reason
= UNWIND_MEMORY_ERROR
;
2110 if (ex
.message
!= NULL
)
2115 /* The error needs to live as long as the frame does.
2116 Allocate using stack local STOP_STRING then assign the
2117 pointer to the frame, this allows the STOP_STRING on the
2118 frame to be of type 'const char *'. */
2119 size
= strlen (ex
.message
) + 1;
2120 stop_string
= (char *) frame_obstack_zalloc (size
);
2121 memcpy (stop_string
, ex
.message
, size
);
2122 this_frame
->stop_string
= stop_string
;
2127 throw_exception (ex
);
2134 /* Construct a new "struct frame_info" and link it previous to
2137 static struct frame_info
*
2138 get_prev_frame_raw (struct frame_info
*this_frame
)
2140 struct frame_info
*prev_frame
;
2142 /* Allocate the new frame but do not wire it in to the frame chain.
2143 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
2144 frame->next to pull some fancy tricks (of course such code is, by
2145 definition, recursive). Try to prevent it.
2147 There is no reason to worry about memory leaks, should the
2148 remainder of the function fail. The allocated memory will be
2149 quickly reclaimed when the frame cache is flushed, and the `we've
2150 been here before' check above will stop repeated memory
2151 allocation calls. */
2152 prev_frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
2153 prev_frame
->level
= this_frame
->level
+ 1;
2155 /* For now, assume we don't have frame chains crossing address
2157 prev_frame
->pspace
= this_frame
->pspace
;
2158 prev_frame
->aspace
= this_frame
->aspace
;
2160 /* Don't yet compute ->unwind (and hence ->type). It is computed
2161 on-demand in get_frame_type, frame_register_unwind, and
2164 /* Don't yet compute the frame's ID. It is computed on-demand by
2167 /* The unwound frame ID is validate at the start of this function,
2168 as part of the logic to decide if that frame should be further
2169 unwound, and not here while the prev frame is being created.
2170 Doing this makes it possible for the user to examine a frame that
2171 has an invalid frame ID.
2173 Some very old VAX code noted: [...] For the sake of argument,
2174 suppose that the stack is somewhat trashed (which is one reason
2175 that "info frame" exists). So, return 0 (indicating we don't
2176 know the address of the arglist) if we don't know what frame this
2180 this_frame
->prev
= prev_frame
;
2181 prev_frame
->next
= this_frame
;
2185 fprintf_unfiltered (gdb_stdlog
, "-> ");
2186 fprint_frame (gdb_stdlog
, prev_frame
);
2187 fprintf_unfiltered (gdb_stdlog
, " }\n");
2193 /* Debug routine to print a NULL frame being returned. */
2196 frame_debug_got_null_frame (struct frame_info
*this_frame
,
2201 fprintf_unfiltered (gdb_stdlog
, "{ get_prev_frame (this_frame=");
2202 if (this_frame
!= NULL
)
2203 fprintf_unfiltered (gdb_stdlog
, "%d", this_frame
->level
);
2205 fprintf_unfiltered (gdb_stdlog
, "<NULL>");
2206 fprintf_unfiltered (gdb_stdlog
, ") -> // %s}\n", reason
);
2210 /* Is this (non-sentinel) frame in the "main"() function? */
2213 inside_main_func (struct frame_info
*this_frame
)
2215 struct bound_minimal_symbol msymbol
;
2218 if (symfile_objfile
== 0)
2220 msymbol
= lookup_minimal_symbol (main_name (), NULL
, symfile_objfile
);
2221 if (msymbol
.minsym
== NULL
)
2223 /* Make certain that the code, and not descriptor, address is
2225 maddr
= gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame
),
2226 BMSYMBOL_VALUE_ADDRESS (msymbol
),
2228 return maddr
== get_frame_func (this_frame
);
2231 /* Test whether THIS_FRAME is inside the process entry point function. */
2234 inside_entry_func (struct frame_info
*this_frame
)
2236 CORE_ADDR entry_point
;
2238 if (!entry_point_address_query (&entry_point
))
2241 return get_frame_func (this_frame
) == entry_point
;
2244 /* Return a structure containing various interesting information about
2245 the frame that called THIS_FRAME. Returns NULL if there is entier
2246 no such frame or the frame fails any of a set of target-independent
2247 condition that should terminate the frame chain (e.g., as unwinding
2250 This function should not contain target-dependent tests, such as
2251 checking whether the program-counter is zero. */
2254 get_prev_frame (struct frame_info
*this_frame
)
2259 /* There is always a frame. If this assertion fails, suspect that
2260 something should be calling get_selected_frame() or
2261 get_current_frame(). */
2262 gdb_assert (this_frame
!= NULL
);
2264 /* If this_frame is the current frame, then compute and stash
2265 its frame id prior to fetching and computing the frame id of the
2266 previous frame. Otherwise, the cycle detection code in
2267 get_prev_frame_if_no_cycle() will not work correctly. When
2268 get_frame_id() is called later on, an assertion error will
2269 be triggered in the event of a cycle between the current
2270 frame and its previous frame. */
2271 if (this_frame
->level
== 0)
2272 get_frame_id (this_frame
);
2274 frame_pc_p
= get_frame_pc_if_available (this_frame
, &frame_pc
);
2276 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
2277 sense to stop unwinding at a dummy frame. One place where a dummy
2278 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
2279 pcsqh register (space register for the instruction at the head of the
2280 instruction queue) cannot be written directly; the only way to set it
2281 is to branch to code that is in the target space. In order to implement
2282 frame dummies on HPUX, the called function is made to jump back to where
2283 the inferior was when the user function was called. If gdb was inside
2284 the main function when we created the dummy frame, the dummy frame will
2285 point inside the main function. */
2286 if (this_frame
->level
>= 0
2287 && get_frame_type (this_frame
) == NORMAL_FRAME
2288 && !backtrace_past_main
2290 && inside_main_func (this_frame
))
2291 /* Don't unwind past main(). Note, this is done _before_ the
2292 frame has been marked as previously unwound. That way if the
2293 user later decides to enable unwinds past main(), that will
2294 automatically happen. */
2296 frame_debug_got_null_frame (this_frame
, "inside main func");
2300 /* If the user's backtrace limit has been exceeded, stop. We must
2301 add two to the current level; one of those accounts for backtrace_limit
2302 being 1-based and the level being 0-based, and the other accounts for
2303 the level of the new frame instead of the level of the current
2305 if (this_frame
->level
+ 2 > backtrace_limit
)
2307 frame_debug_got_null_frame (this_frame
, "backtrace limit exceeded");
2311 /* If we're already inside the entry function for the main objfile,
2312 then it isn't valid. Don't apply this test to a dummy frame -
2313 dummy frame PCs typically land in the entry func. Don't apply
2314 this test to the sentinel frame. Sentinel frames should always
2315 be allowed to unwind. */
2316 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
2317 wasn't checking for "main" in the minimal symbols. With that
2318 fixed asm-source tests now stop in "main" instead of halting the
2319 backtrace in weird and wonderful ways somewhere inside the entry
2320 file. Suspect that tests for inside the entry file/func were
2321 added to work around that (now fixed) case. */
2322 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
2323 suggested having the inside_entry_func test use the
2324 inside_main_func() msymbol trick (along with entry_point_address()
2325 I guess) to determine the address range of the start function.
2326 That should provide a far better stopper than the current
2328 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
2329 applied tail-call optimizations to main so that a function called
2330 from main returns directly to the caller of main. Since we don't
2331 stop at main, we should at least stop at the entry point of the
2333 if (this_frame
->level
>= 0
2334 && get_frame_type (this_frame
) == NORMAL_FRAME
2335 && !backtrace_past_entry
2337 && inside_entry_func (this_frame
))
2339 frame_debug_got_null_frame (this_frame
, "inside entry func");
2343 /* Assume that the only way to get a zero PC is through something
2344 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
2345 will never unwind a zero PC. */
2346 if (this_frame
->level
> 0
2347 && (get_frame_type (this_frame
) == NORMAL_FRAME
2348 || get_frame_type (this_frame
) == INLINE_FRAME
)
2349 && get_frame_type (get_next_frame (this_frame
)) == NORMAL_FRAME
2350 && frame_pc_p
&& frame_pc
== 0)
2352 frame_debug_got_null_frame (this_frame
, "zero PC");
2356 return get_prev_frame_always (this_frame
);
2360 get_prev_frame_id_by_id (struct frame_id id
)
2362 struct frame_id prev_id
;
2363 struct frame_info
*frame
;
2365 frame
= frame_find_by_id (id
);
2368 prev_id
= get_frame_id (get_prev_frame (frame
));
2370 prev_id
= null_frame_id
;
2376 get_frame_pc (struct frame_info
*frame
)
2378 gdb_assert (frame
->next
!= NULL
);
2379 return frame_unwind_pc (frame
->next
);
2383 get_frame_pc_if_available (struct frame_info
*frame
, CORE_ADDR
*pc
)
2386 gdb_assert (frame
->next
!= NULL
);
2390 *pc
= frame_unwind_pc (frame
->next
);
2392 CATCH (ex
, RETURN_MASK_ERROR
)
2394 if (ex
.error
== NOT_AVAILABLE_ERROR
)
2397 throw_exception (ex
);
2404 /* Return an address that falls within THIS_FRAME's code block. */
2407 get_frame_address_in_block (struct frame_info
*this_frame
)
2409 /* A draft address. */
2410 CORE_ADDR pc
= get_frame_pc (this_frame
);
2412 struct frame_info
*next_frame
= this_frame
->next
;
2414 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
2415 Normally the resume address is inside the body of the function
2416 associated with THIS_FRAME, but there is a special case: when
2417 calling a function which the compiler knows will never return
2418 (for instance abort), the call may be the very last instruction
2419 in the calling function. The resume address will point after the
2420 call and may be at the beginning of a different function
2423 If THIS_FRAME is a signal frame or dummy frame, then we should
2424 not adjust the unwound PC. For a dummy frame, GDB pushed the
2425 resume address manually onto the stack. For a signal frame, the
2426 OS may have pushed the resume address manually and invoked the
2427 handler (e.g. GNU/Linux), or invoked the trampoline which called
2428 the signal handler - but in either case the signal handler is
2429 expected to return to the trampoline. So in both of these
2430 cases we know that the resume address is executable and
2431 related. So we only need to adjust the PC if THIS_FRAME
2432 is a normal function.
2434 If the program has been interrupted while THIS_FRAME is current,
2435 then clearly the resume address is inside the associated
2436 function. There are three kinds of interruption: debugger stop
2437 (next frame will be SENTINEL_FRAME), operating system
2438 signal or exception (next frame will be SIGTRAMP_FRAME),
2439 or debugger-induced function call (next frame will be
2440 DUMMY_FRAME). So we only need to adjust the PC if
2441 NEXT_FRAME is a normal function.
2443 We check the type of NEXT_FRAME first, since it is already
2444 known; frame type is determined by the unwinder, and since
2445 we have THIS_FRAME we've already selected an unwinder for
2448 If the next frame is inlined, we need to keep going until we find
2449 the real function - for instance, if a signal handler is invoked
2450 while in an inlined function, then the code address of the
2451 "calling" normal function should not be adjusted either. */
2453 while (get_frame_type (next_frame
) == INLINE_FRAME
)
2454 next_frame
= next_frame
->next
;
2456 if ((get_frame_type (next_frame
) == NORMAL_FRAME
2457 || get_frame_type (next_frame
) == TAILCALL_FRAME
)
2458 && (get_frame_type (this_frame
) == NORMAL_FRAME
2459 || get_frame_type (this_frame
) == TAILCALL_FRAME
2460 || get_frame_type (this_frame
) == INLINE_FRAME
))
2467 get_frame_address_in_block_if_available (struct frame_info
*this_frame
,
2473 *pc
= get_frame_address_in_block (this_frame
);
2475 CATCH (ex
, RETURN_MASK_ERROR
)
2477 if (ex
.error
== NOT_AVAILABLE_ERROR
)
2479 throw_exception (ex
);
2487 find_frame_sal (frame_info
*frame
)
2489 struct frame_info
*next_frame
;
2493 /* If the next frame represents an inlined function call, this frame's
2494 sal is the "call site" of that inlined function, which can not
2495 be inferred from get_frame_pc. */
2496 next_frame
= get_next_frame (frame
);
2497 if (frame_inlined_callees (frame
) > 0)
2502 sym
= get_frame_function (next_frame
);
2504 sym
= inline_skipped_symbol (inferior_ptid
);
2506 /* If frame is inline, it certainly has symbols. */
2509 symtab_and_line sal
;
2510 if (SYMBOL_LINE (sym
) != 0)
2512 sal
.symtab
= symbol_symtab (sym
);
2513 sal
.line
= SYMBOL_LINE (sym
);
2516 /* If the symbol does not have a location, we don't know where
2517 the call site is. Do not pretend to. This is jarring, but
2518 we can't do much better. */
2519 sal
.pc
= get_frame_pc (frame
);
2521 sal
.pspace
= get_frame_program_space (frame
);
2525 /* If FRAME is not the innermost frame, that normally means that
2526 FRAME->pc points at the return instruction (which is *after* the
2527 call instruction), and we want to get the line containing the
2528 call (because the call is where the user thinks the program is).
2529 However, if the next frame is either a SIGTRAMP_FRAME or a
2530 DUMMY_FRAME, then the next frame will contain a saved interrupt
2531 PC and such a PC indicates the current (rather than next)
2532 instruction/line, consequently, for such cases, want to get the
2533 line containing fi->pc. */
2534 if (!get_frame_pc_if_available (frame
, &pc
))
2537 notcurrent
= (pc
!= get_frame_address_in_block (frame
));
2538 return find_pc_line (pc
, notcurrent
);
2541 /* Per "frame.h", return the ``address'' of the frame. Code should
2542 really be using get_frame_id(). */
2544 get_frame_base (struct frame_info
*fi
)
2546 return get_frame_id (fi
).stack_addr
;
2549 /* High-level offsets into the frame. Used by the debug info. */
2552 get_frame_base_address (struct frame_info
*fi
)
2554 if (get_frame_type (fi
) != NORMAL_FRAME
)
2556 if (fi
->base
== NULL
)
2557 fi
->base
= frame_base_find_by_frame (fi
);
2558 /* Sneaky: If the low-level unwind and high-level base code share a
2559 common unwinder, let them share the prologue cache. */
2560 if (fi
->base
->unwind
== fi
->unwind
)
2561 return fi
->base
->this_base (fi
, &fi
->prologue_cache
);
2562 return fi
->base
->this_base (fi
, &fi
->base_cache
);
2566 get_frame_locals_address (struct frame_info
*fi
)
2568 if (get_frame_type (fi
) != NORMAL_FRAME
)
2570 /* If there isn't a frame address method, find it. */
2571 if (fi
->base
== NULL
)
2572 fi
->base
= frame_base_find_by_frame (fi
);
2573 /* Sneaky: If the low-level unwind and high-level base code share a
2574 common unwinder, let them share the prologue cache. */
2575 if (fi
->base
->unwind
== fi
->unwind
)
2576 return fi
->base
->this_locals (fi
, &fi
->prologue_cache
);
2577 return fi
->base
->this_locals (fi
, &fi
->base_cache
);
2581 get_frame_args_address (struct frame_info
*fi
)
2583 if (get_frame_type (fi
) != NORMAL_FRAME
)
2585 /* If there isn't a frame address method, find it. */
2586 if (fi
->base
== NULL
)
2587 fi
->base
= frame_base_find_by_frame (fi
);
2588 /* Sneaky: If the low-level unwind and high-level base code share a
2589 common unwinder, let them share the prologue cache. */
2590 if (fi
->base
->unwind
== fi
->unwind
)
2591 return fi
->base
->this_args (fi
, &fi
->prologue_cache
);
2592 return fi
->base
->this_args (fi
, &fi
->base_cache
);
2595 /* Return true if the frame unwinder for frame FI is UNWINDER; false
2599 frame_unwinder_is (struct frame_info
*fi
, const struct frame_unwind
*unwinder
)
2601 if (fi
->unwind
== NULL
)
2602 frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
2603 return fi
->unwind
== unwinder
;
2606 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
2607 or -1 for a NULL frame. */
2610 frame_relative_level (struct frame_info
*fi
)
2619 get_frame_type (struct frame_info
*frame
)
2621 if (frame
->unwind
== NULL
)
2622 /* Initialize the frame's unwinder because that's what
2623 provides the frame's type. */
2624 frame_unwind_find_by_frame (frame
, &frame
->prologue_cache
);
2625 return frame
->unwind
->type
;
2628 struct program_space
*
2629 get_frame_program_space (struct frame_info
*frame
)
2631 return frame
->pspace
;
2634 struct program_space
*
2635 frame_unwind_program_space (struct frame_info
*this_frame
)
2637 gdb_assert (this_frame
);
2639 /* This is really a placeholder to keep the API consistent --- we
2640 assume for now that we don't have frame chains crossing
2642 return this_frame
->pspace
;
2645 const address_space
*
2646 get_frame_address_space (struct frame_info
*frame
)
2648 return frame
->aspace
;
2651 /* Memory access methods. */
2654 get_frame_memory (struct frame_info
*this_frame
, CORE_ADDR addr
,
2655 gdb_byte
*buf
, int len
)
2657 read_memory (addr
, buf
, len
);
2661 get_frame_memory_signed (struct frame_info
*this_frame
, CORE_ADDR addr
,
2664 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2665 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
2667 return read_memory_integer (addr
, len
, byte_order
);
2671 get_frame_memory_unsigned (struct frame_info
*this_frame
, CORE_ADDR addr
,
2674 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2675 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
2677 return read_memory_unsigned_integer (addr
, len
, byte_order
);
2681 safe_frame_unwind_memory (struct frame_info
*this_frame
,
2682 CORE_ADDR addr
, gdb_byte
*buf
, int len
)
2684 /* NOTE: target_read_memory returns zero on success! */
2685 return !target_read_memory (addr
, buf
, len
);
2688 /* Architecture methods. */
2691 get_frame_arch (struct frame_info
*this_frame
)
2693 return frame_unwind_arch (this_frame
->next
);
2697 frame_unwind_arch (struct frame_info
*next_frame
)
2699 if (!next_frame
->prev_arch
.p
)
2701 struct gdbarch
*arch
;
2703 if (next_frame
->unwind
== NULL
)
2704 frame_unwind_find_by_frame (next_frame
, &next_frame
->prologue_cache
);
2706 if (next_frame
->unwind
->prev_arch
!= NULL
)
2707 arch
= next_frame
->unwind
->prev_arch (next_frame
,
2708 &next_frame
->prologue_cache
);
2710 arch
= get_frame_arch (next_frame
);
2712 next_frame
->prev_arch
.arch
= arch
;
2713 next_frame
->prev_arch
.p
= 1;
2715 fprintf_unfiltered (gdb_stdlog
,
2716 "{ frame_unwind_arch (next_frame=%d) -> %s }\n",
2718 gdbarch_bfd_arch_info (arch
)->printable_name
);
2721 return next_frame
->prev_arch
.arch
;
2725 frame_unwind_caller_arch (struct frame_info
*next_frame
)
2727 next_frame
= skip_artificial_frames (next_frame
);
2729 /* We must have a non-artificial frame. The caller is supposed to check
2730 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
2732 gdb_assert (next_frame
!= NULL
);
2734 return frame_unwind_arch (next_frame
);
2737 /* Gets the language of FRAME. */
2740 get_frame_language (struct frame_info
*frame
)
2745 gdb_assert (frame
!= NULL
);
2747 /* We determine the current frame language by looking up its
2748 associated symtab. To retrieve this symtab, we use the frame
2749 PC. However we cannot use the frame PC as is, because it
2750 usually points to the instruction following the "call", which
2751 is sometimes the first instruction of another function. So
2752 we rely on get_frame_address_in_block(), it provides us with
2753 a PC that is guaranteed to be inside the frame's code
2758 pc
= get_frame_address_in_block (frame
);
2761 CATCH (ex
, RETURN_MASK_ERROR
)
2763 if (ex
.error
!= NOT_AVAILABLE_ERROR
)
2764 throw_exception (ex
);
2770 struct compunit_symtab
*cust
= find_pc_compunit_symtab (pc
);
2773 return compunit_language (cust
);
2776 return language_unknown
;
2779 /* Stack pointer methods. */
2782 get_frame_sp (struct frame_info
*this_frame
)
2784 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2786 /* Normality - an architecture that provides a way of obtaining any
2787 frame inner-most address. */
2788 if (gdbarch_unwind_sp_p (gdbarch
))
2789 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
2790 operate on THIS_FRAME now. */
2791 return gdbarch_unwind_sp (gdbarch
, this_frame
->next
);
2792 /* Now things are really are grim. Hope that the value returned by
2793 the gdbarch_sp_regnum register is meaningful. */
2794 if (gdbarch_sp_regnum (gdbarch
) >= 0)
2795 return get_frame_register_unsigned (this_frame
,
2796 gdbarch_sp_regnum (gdbarch
));
2797 internal_error (__FILE__
, __LINE__
, _("Missing unwind SP method"));
2800 /* Return the reason why we can't unwind past FRAME. */
2802 enum unwind_stop_reason
2803 get_frame_unwind_stop_reason (struct frame_info
*frame
)
2805 /* Fill-in STOP_REASON. */
2806 get_prev_frame_always (frame
);
2807 gdb_assert (frame
->prev_p
);
2809 return frame
->stop_reason
;
2812 /* Return a string explaining REASON. */
2815 unwind_stop_reason_to_string (enum unwind_stop_reason reason
)
2819 #define SET(name, description) \
2820 case name: return _(description);
2821 #include "unwind_stop_reasons.def"
2825 internal_error (__FILE__
, __LINE__
,
2826 "Invalid frame stop reason");
2831 frame_stop_reason_string (struct frame_info
*fi
)
2833 gdb_assert (fi
->prev_p
);
2834 gdb_assert (fi
->prev
== NULL
);
2836 /* Return the specific string if we have one. */
2837 if (fi
->stop_string
!= NULL
)
2838 return fi
->stop_string
;
2840 /* Return the generic string if we have nothing better. */
2841 return unwind_stop_reason_to_string (fi
->stop_reason
);
2844 /* Return the enum symbol name of REASON as a string, to use in debug
2848 frame_stop_reason_symbol_string (enum unwind_stop_reason reason
)
2852 #define SET(name, description) \
2853 case name: return #name;
2854 #include "unwind_stop_reasons.def"
2858 internal_error (__FILE__
, __LINE__
,
2859 "Invalid frame stop reason");
2863 /* Clean up after a failed (wrong unwinder) attempt to unwind past
2867 frame_cleanup_after_sniffer (struct frame_info
*frame
)
2869 /* The sniffer should not allocate a prologue cache if it did not
2870 match this frame. */
2871 gdb_assert (frame
->prologue_cache
== NULL
);
2873 /* No sniffer should extend the frame chain; sniff based on what is
2875 gdb_assert (!frame
->prev_p
);
2877 /* The sniffer should not check the frame's ID; that's circular. */
2878 gdb_assert (!frame
->this_id
.p
);
2880 /* Clear cached fields dependent on the unwinder.
2882 The previous PC is independent of the unwinder, but the previous
2883 function is not (see get_frame_address_in_block). */
2884 frame
->prev_func
.p
= 0;
2885 frame
->prev_func
.addr
= 0;
2887 /* Discard the unwinder last, so that we can easily find it if an assertion
2888 in this function triggers. */
2889 frame
->unwind
= NULL
;
2892 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
2893 If sniffing fails, the caller should be sure to call
2894 frame_cleanup_after_sniffer. */
2897 frame_prepare_for_sniffer (struct frame_info
*frame
,
2898 const struct frame_unwind
*unwind
)
2900 gdb_assert (frame
->unwind
== NULL
);
2901 frame
->unwind
= unwind
;
2904 static struct cmd_list_element
*set_backtrace_cmdlist
;
2905 static struct cmd_list_element
*show_backtrace_cmdlist
;
2908 set_backtrace_cmd (const char *args
, int from_tty
)
2910 help_list (set_backtrace_cmdlist
, "set backtrace ", all_commands
,
2915 show_backtrace_cmd (const char *args
, int from_tty
)
2917 cmd_show_list (show_backtrace_cmdlist
, from_tty
, "");
2921 _initialize_frame (void)
2923 obstack_init (&frame_cache_obstack
);
2925 frame_stash_create ();
2927 observer_attach_target_changed (frame_observer_target_changed
);
2929 add_prefix_cmd ("backtrace", class_maintenance
, set_backtrace_cmd
, _("\
2930 Set backtrace specific variables.\n\
2931 Configure backtrace variables such as the backtrace limit"),
2932 &set_backtrace_cmdlist
, "set backtrace ",
2933 0/*allow-unknown*/, &setlist
);
2934 add_prefix_cmd ("backtrace", class_maintenance
, show_backtrace_cmd
, _("\
2935 Show backtrace specific variables\n\
2936 Show backtrace variables such as the backtrace limit"),
2937 &show_backtrace_cmdlist
, "show backtrace ",
2938 0/*allow-unknown*/, &showlist
);
2940 add_setshow_boolean_cmd ("past-main", class_obscure
,
2941 &backtrace_past_main
, _("\
2942 Set whether backtraces should continue past \"main\"."), _("\
2943 Show whether backtraces should continue past \"main\"."), _("\
2944 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
2945 the backtrace at \"main\". Set this variable if you need to see the rest\n\
2946 of the stack trace."),
2948 show_backtrace_past_main
,
2949 &set_backtrace_cmdlist
,
2950 &show_backtrace_cmdlist
);
2952 add_setshow_boolean_cmd ("past-entry", class_obscure
,
2953 &backtrace_past_entry
, _("\
2954 Set whether backtraces should continue past the entry point of a program."),
2956 Show whether backtraces should continue past the entry point of a program."),
2958 Normally there are no callers beyond the entry point of a program, so GDB\n\
2959 will terminate the backtrace there. Set this variable if you need to see\n\
2960 the rest of the stack trace."),
2962 show_backtrace_past_entry
,
2963 &set_backtrace_cmdlist
,
2964 &show_backtrace_cmdlist
);
2966 add_setshow_uinteger_cmd ("limit", class_obscure
,
2967 &backtrace_limit
, _("\
2968 Set an upper bound on the number of backtrace levels."), _("\
2969 Show the upper bound on the number of backtrace levels."), _("\
2970 No more than the specified number of frames can be displayed or examined.\n\
2971 Literal \"unlimited\" or zero means no limit."),
2973 show_backtrace_limit
,
2974 &set_backtrace_cmdlist
,
2975 &show_backtrace_cmdlist
);
2977 /* Debug this files internals. */
2978 add_setshow_zuinteger_cmd ("frame", class_maintenance
, &frame_debug
, _("\
2979 Set frame debugging."), _("\
2980 Show frame debugging."), _("\
2981 When non-zero, frame specific internal debugging is enabled."),
2984 &setdebuglist
, &showdebuglist
);