1 /* Cache and manage frames for GDB, the GNU debugger.
3 Copyright (C) 1986-2018 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"
37 #include "observable.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
<readonly_detached_regcache
>
1021 frame_save_as_regcache (struct frame_info
*this_frame
)
1023 std::unique_ptr
<readonly_detached_regcache
> regcache
1024 (new readonly_detached_regcache (get_frame_arch (this_frame
),
1025 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
<readonly_detached_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 get_current_regcache ()->restore (scratch
.get ());
1074 /* We've made right mess of GDB's local state, just discard
1076 reinit_frame_cache ();
1080 frame_register_unwind (struct frame_info
*frame
, int regnum
,
1081 int *optimizedp
, int *unavailablep
,
1082 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
1083 int *realnump
, gdb_byte
*bufferp
)
1085 struct value
*value
;
1087 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1088 that the value proper does not need to be fetched. */
1089 gdb_assert (optimizedp
!= NULL
);
1090 gdb_assert (lvalp
!= NULL
);
1091 gdb_assert (addrp
!= NULL
);
1092 gdb_assert (realnump
!= NULL
);
1093 /* gdb_assert (bufferp != NULL); */
1095 value
= frame_unwind_register_value (frame
, regnum
);
1097 gdb_assert (value
!= NULL
);
1099 *optimizedp
= value_optimized_out (value
);
1100 *unavailablep
= !value_entirely_available (value
);
1101 *lvalp
= VALUE_LVAL (value
);
1102 *addrp
= value_address (value
);
1103 if (*lvalp
== lval_register
)
1104 *realnump
= VALUE_REGNUM (value
);
1110 if (!*optimizedp
&& !*unavailablep
)
1111 memcpy (bufferp
, value_contents_all (value
),
1112 TYPE_LENGTH (value_type (value
)));
1114 memset (bufferp
, 0, TYPE_LENGTH (value_type (value
)));
1117 /* Dispose of the new value. This prevents watchpoints from
1118 trying to watch the saved frame pointer. */
1119 release_value (value
);
1123 frame_register (struct frame_info
*frame
, int regnum
,
1124 int *optimizedp
, int *unavailablep
, enum lval_type
*lvalp
,
1125 CORE_ADDR
*addrp
, int *realnump
, gdb_byte
*bufferp
)
1127 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1128 that the value proper does not need to be fetched. */
1129 gdb_assert (optimizedp
!= NULL
);
1130 gdb_assert (lvalp
!= NULL
);
1131 gdb_assert (addrp
!= NULL
);
1132 gdb_assert (realnump
!= NULL
);
1133 /* gdb_assert (bufferp != NULL); */
1135 /* Obtain the register value by unwinding the register from the next
1136 (more inner frame). */
1137 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
1138 frame_register_unwind (frame
->next
, regnum
, optimizedp
, unavailablep
,
1139 lvalp
, addrp
, realnump
, bufferp
);
1143 frame_unwind_register (struct frame_info
*frame
, int regnum
, gdb_byte
*buf
)
1149 enum lval_type lval
;
1151 frame_register_unwind (frame
, regnum
, &optimized
, &unavailable
,
1152 &lval
, &addr
, &realnum
, buf
);
1155 throw_error (OPTIMIZED_OUT_ERROR
,
1156 _("Register %d was not saved"), regnum
);
1158 throw_error (NOT_AVAILABLE_ERROR
,
1159 _("Register %d is not available"), regnum
);
1163 get_frame_register (struct frame_info
*frame
,
1164 int regnum
, gdb_byte
*buf
)
1166 frame_unwind_register (frame
->next
, regnum
, buf
);
1170 frame_unwind_register_value (struct frame_info
*frame
, int regnum
)
1172 struct gdbarch
*gdbarch
;
1173 struct value
*value
;
1175 gdb_assert (frame
!= NULL
);
1176 gdbarch
= frame_unwind_arch (frame
);
1180 fprintf_unfiltered (gdb_stdlog
,
1181 "{ frame_unwind_register_value "
1182 "(frame=%d,regnum=%d(%s),...) ",
1183 frame
->level
, regnum
,
1184 user_reg_map_regnum_to_name (gdbarch
, regnum
));
1187 /* Find the unwinder. */
1188 if (frame
->unwind
== NULL
)
1189 frame_unwind_find_by_frame (frame
, &frame
->prologue_cache
);
1191 /* Ask this frame to unwind its register. */
1192 value
= frame
->unwind
->prev_register (frame
, &frame
->prologue_cache
, regnum
);
1196 fprintf_unfiltered (gdb_stdlog
, "->");
1197 if (value_optimized_out (value
))
1199 fprintf_unfiltered (gdb_stdlog
, " ");
1200 val_print_optimized_out (value
, gdb_stdlog
);
1204 if (VALUE_LVAL (value
) == lval_register
)
1205 fprintf_unfiltered (gdb_stdlog
, " register=%d",
1206 VALUE_REGNUM (value
));
1207 else if (VALUE_LVAL (value
) == lval_memory
)
1208 fprintf_unfiltered (gdb_stdlog
, " address=%s",
1210 value_address (value
)));
1212 fprintf_unfiltered (gdb_stdlog
, " computed");
1214 if (value_lazy (value
))
1215 fprintf_unfiltered (gdb_stdlog
, " lazy");
1219 const gdb_byte
*buf
= value_contents (value
);
1221 fprintf_unfiltered (gdb_stdlog
, " bytes=");
1222 fprintf_unfiltered (gdb_stdlog
, "[");
1223 for (i
= 0; i
< register_size (gdbarch
, regnum
); i
++)
1224 fprintf_unfiltered (gdb_stdlog
, "%02x", buf
[i
]);
1225 fprintf_unfiltered (gdb_stdlog
, "]");
1229 fprintf_unfiltered (gdb_stdlog
, " }\n");
1236 get_frame_register_value (struct frame_info
*frame
, int regnum
)
1238 return frame_unwind_register_value (frame
->next
, regnum
);
1242 frame_unwind_register_signed (struct frame_info
*frame
, int regnum
)
1244 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
1245 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1246 int size
= register_size (gdbarch
, regnum
);
1247 struct value
*value
= frame_unwind_register_value (frame
, regnum
);
1249 gdb_assert (value
!= NULL
);
1251 if (value_optimized_out (value
))
1253 throw_error (OPTIMIZED_OUT_ERROR
,
1254 _("Register %d was not saved"), regnum
);
1256 if (!value_entirely_available (value
))
1258 throw_error (NOT_AVAILABLE_ERROR
,
1259 _("Register %d is not available"), regnum
);
1262 LONGEST r
= extract_signed_integer (value_contents_all (value
), size
,
1265 release_value (value
);
1270 get_frame_register_signed (struct frame_info
*frame
, int regnum
)
1272 return frame_unwind_register_signed (frame
->next
, regnum
);
1276 frame_unwind_register_unsigned (struct frame_info
*frame
, int regnum
)
1278 struct gdbarch
*gdbarch
= frame_unwind_arch (frame
);
1279 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1280 int size
= register_size (gdbarch
, regnum
);
1281 struct value
*value
= frame_unwind_register_value (frame
, regnum
);
1283 gdb_assert (value
!= NULL
);
1285 if (value_optimized_out (value
))
1287 throw_error (OPTIMIZED_OUT_ERROR
,
1288 _("Register %d was not saved"), regnum
);
1290 if (!value_entirely_available (value
))
1292 throw_error (NOT_AVAILABLE_ERROR
,
1293 _("Register %d is not available"), regnum
);
1296 ULONGEST r
= extract_unsigned_integer (value_contents_all (value
), size
,
1299 release_value (value
);
1304 get_frame_register_unsigned (struct frame_info
*frame
, int regnum
)
1306 return frame_unwind_register_unsigned (frame
->next
, regnum
);
1310 read_frame_register_unsigned (struct frame_info
*frame
, int regnum
,
1313 struct value
*regval
= get_frame_register_value (frame
, regnum
);
1315 if (!value_optimized_out (regval
)
1316 && value_entirely_available (regval
))
1318 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1319 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1320 int size
= register_size (gdbarch
, VALUE_REGNUM (regval
));
1322 *val
= extract_unsigned_integer (value_contents (regval
), size
, byte_order
);
1330 put_frame_register (struct frame_info
*frame
, int regnum
,
1331 const gdb_byte
*buf
)
1333 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1337 enum lval_type lval
;
1340 frame_register (frame
, regnum
, &optim
, &unavail
,
1341 &lval
, &addr
, &realnum
, NULL
);
1343 error (_("Attempt to assign to a register that was not saved."));
1348 write_memory (addr
, buf
, register_size (gdbarch
, regnum
));
1352 regcache_cooked_write (get_current_regcache (), realnum
, buf
);
1355 error (_("Attempt to assign to an unmodifiable value."));
1359 /* This function is deprecated. Use get_frame_register_value instead,
1360 which provides more accurate information.
1362 Find and return the value of REGNUM for the specified stack frame.
1363 The number of bytes copied is REGISTER_SIZE (REGNUM).
1365 Returns 0 if the register value could not be found. */
1368 deprecated_frame_register_read (struct frame_info
*frame
, int regnum
,
1373 enum lval_type lval
;
1377 frame_register (frame
, regnum
, &optimized
, &unavailable
,
1378 &lval
, &addr
, &realnum
, myaddr
);
1380 return !optimized
&& !unavailable
;
1384 get_frame_register_bytes (struct frame_info
*frame
, int regnum
,
1385 CORE_ADDR offset
, int len
, gdb_byte
*myaddr
,
1386 int *optimizedp
, int *unavailablep
)
1388 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1393 /* Skip registers wholly inside of OFFSET. */
1394 while (offset
>= register_size (gdbarch
, regnum
))
1396 offset
-= register_size (gdbarch
, regnum
);
1400 /* Ensure that we will not read beyond the end of the register file.
1401 This can only ever happen if the debug information is bad. */
1403 numregs
= gdbarch_num_regs (gdbarch
) + gdbarch_num_pseudo_regs (gdbarch
);
1404 for (i
= regnum
; i
< numregs
; i
++)
1406 int thissize
= register_size (gdbarch
, i
);
1409 break; /* This register is not available on this architecture. */
1410 maxsize
+= thissize
;
1413 error (_("Bad debug information detected: "
1414 "Attempt to read %d bytes from registers."), len
);
1416 /* Copy the data. */
1419 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
1424 if (curr_len
== register_size (gdbarch
, regnum
))
1426 enum lval_type lval
;
1430 frame_register (frame
, regnum
, optimizedp
, unavailablep
,
1431 &lval
, &addr
, &realnum
, myaddr
);
1432 if (*optimizedp
|| *unavailablep
)
1437 struct value
*value
= frame_unwind_register_value (frame
->next
,
1439 gdb_assert (value
!= NULL
);
1440 *optimizedp
= value_optimized_out (value
);
1441 *unavailablep
= !value_entirely_available (value
);
1443 if (*optimizedp
|| *unavailablep
)
1445 release_value (value
);
1448 memcpy (myaddr
, value_contents_all (value
) + offset
, curr_len
);
1449 release_value (value
);
1464 put_frame_register_bytes (struct frame_info
*frame
, int regnum
,
1465 CORE_ADDR offset
, int len
, const gdb_byte
*myaddr
)
1467 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1469 /* Skip registers wholly inside of OFFSET. */
1470 while (offset
>= register_size (gdbarch
, regnum
))
1472 offset
-= register_size (gdbarch
, regnum
);
1476 /* Copy the data. */
1479 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
1484 if (curr_len
== register_size (gdbarch
, regnum
))
1486 put_frame_register (frame
, regnum
, myaddr
);
1490 struct value
*value
= frame_unwind_register_value (frame
->next
,
1492 gdb_assert (value
!= NULL
);
1494 memcpy ((char *) value_contents_writeable (value
) + offset
, myaddr
,
1496 put_frame_register (frame
, regnum
, value_contents_raw (value
));
1497 release_value (value
);
1507 /* Create a sentinel frame. */
1509 static struct frame_info
*
1510 create_sentinel_frame (struct program_space
*pspace
, struct regcache
*regcache
)
1512 struct frame_info
*frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1515 frame
->pspace
= pspace
;
1516 frame
->aspace
= regcache
->aspace ();
1517 /* Explicitly initialize the sentinel frame's cache. Provide it
1518 with the underlying regcache. In the future additional
1519 information, such as the frame's thread will be added. */
1520 frame
->prologue_cache
= sentinel_frame_cache (regcache
);
1521 /* For the moment there is only one sentinel frame implementation. */
1522 frame
->unwind
= &sentinel_frame_unwind
;
1523 /* Link this frame back to itself. The frame is self referential
1524 (the unwound PC is the same as the pc), so make it so. */
1525 frame
->next
= frame
;
1526 /* The sentinel frame has a special ID. */
1527 frame
->this_id
.p
= 1;
1528 frame
->this_id
.value
= sentinel_frame_id
;
1531 fprintf_unfiltered (gdb_stdlog
, "{ create_sentinel_frame (...) -> ");
1532 fprint_frame (gdb_stdlog
, frame
);
1533 fprintf_unfiltered (gdb_stdlog
, " }\n");
1538 /* Cache for frame addresses already read by gdb. Valid only while
1539 inferior is stopped. Control variables for the frame cache should
1540 be local to this module. */
1542 static struct obstack frame_cache_obstack
;
1545 frame_obstack_zalloc (unsigned long size
)
1547 void *data
= obstack_alloc (&frame_cache_obstack
, size
);
1549 memset (data
, 0, size
);
1553 static struct frame_info
*get_prev_frame_always_1 (struct frame_info
*this_frame
);
1556 get_current_frame (void)
1558 struct frame_info
*current_frame
;
1560 /* First check, and report, the lack of registers. Having GDB
1561 report "No stack!" or "No memory" when the target doesn't even
1562 have registers is very confusing. Besides, "printcmd.exp"
1563 explicitly checks that ``print $pc'' with no registers prints "No
1565 if (!target_has_registers
)
1566 error (_("No registers."));
1567 if (!target_has_stack
)
1568 error (_("No stack."));
1569 if (!target_has_memory
)
1570 error (_("No memory."));
1571 /* Traceframes are effectively a substitute for the live inferior. */
1572 if (get_traceframe_number () < 0)
1573 validate_registers_access ();
1575 if (sentinel_frame
== NULL
)
1577 create_sentinel_frame (current_program_space
, get_current_regcache ());
1579 /* Set the current frame before computing the frame id, to avoid
1580 recursion inside compute_frame_id, in case the frame's
1581 unwinder decides to do a symbol lookup (which depends on the
1582 selected frame's block).
1584 This call must always succeed. In particular, nothing inside
1585 get_prev_frame_always_1 should try to unwind from the
1586 sentinel frame, because that could fail/throw, and we always
1587 want to leave with the current frame created and linked in --
1588 we should never end up with the sentinel frame as outermost
1590 current_frame
= get_prev_frame_always_1 (sentinel_frame
);
1591 gdb_assert (current_frame
!= NULL
);
1593 return current_frame
;
1596 /* The "selected" stack frame is used by default for local and arg
1597 access. May be zero, for no selected frame. */
1599 static struct frame_info
*selected_frame
;
1602 has_stack_frames (void)
1604 if (!target_has_registers
|| !target_has_stack
|| !target_has_memory
)
1607 /* Traceframes are effectively a substitute for the live inferior. */
1608 if (get_traceframe_number () < 0)
1610 /* No current inferior, no frame. */
1611 if (ptid_equal (inferior_ptid
, null_ptid
))
1614 /* Don't try to read from a dead thread. */
1615 if (is_exited (inferior_ptid
))
1618 /* ... or from a spinning thread. */
1619 if (is_executing (inferior_ptid
))
1626 /* Return the selected frame. Always non-NULL (unless there isn't an
1627 inferior sufficient for creating a frame) in which case an error is
1631 get_selected_frame (const char *message
)
1633 if (selected_frame
== NULL
)
1635 if (message
!= NULL
&& !has_stack_frames ())
1636 error (("%s"), message
);
1637 /* Hey! Don't trust this. It should really be re-finding the
1638 last selected frame of the currently selected thread. This,
1639 though, is better than nothing. */
1640 select_frame (get_current_frame ());
1642 /* There is always a frame. */
1643 gdb_assert (selected_frame
!= NULL
);
1644 return selected_frame
;
1647 /* If there is a selected frame, return it. Otherwise, return NULL. */
1650 get_selected_frame_if_set (void)
1652 return selected_frame
;
1655 /* This is a variant of get_selected_frame() which can be called when
1656 the inferior does not have a frame; in that case it will return
1657 NULL instead of calling error(). */
1660 deprecated_safe_get_selected_frame (void)
1662 if (!has_stack_frames ())
1664 return get_selected_frame (NULL
);
1667 /* Select frame FI (or NULL - to invalidate the current frame). */
1670 select_frame (struct frame_info
*fi
)
1672 selected_frame
= fi
;
1673 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
1674 frame is being invalidated. */
1676 /* FIXME: kseitz/2002-08-28: It would be nice to call
1677 selected_frame_level_changed_event() right here, but due to limitations
1678 in the current interfaces, we would end up flooding UIs with events
1679 because select_frame() is used extensively internally.
1681 Once we have frame-parameterized frame (and frame-related) commands,
1682 the event notification can be moved here, since this function will only
1683 be called when the user's selected frame is being changed. */
1685 /* Ensure that symbols for this frame are read in. Also, determine the
1686 source language of this frame, and switch to it if desired. */
1691 /* We retrieve the frame's symtab by using the frame PC.
1692 However we cannot use the frame PC as-is, because it usually
1693 points to the instruction following the "call", which is
1694 sometimes the first instruction of another function. So we
1695 rely on get_frame_address_in_block() which provides us with a
1696 PC which is guaranteed to be inside the frame's code
1698 if (get_frame_address_in_block_if_available (fi
, &pc
))
1700 struct compunit_symtab
*cust
= find_pc_compunit_symtab (pc
);
1703 && compunit_language (cust
) != current_language
->la_language
1704 && compunit_language (cust
) != language_unknown
1705 && language_mode
== language_mode_auto
)
1706 set_language (compunit_language (cust
));
1711 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
1712 Always returns a non-NULL value. */
1715 create_new_frame (CORE_ADDR addr
, CORE_ADDR pc
)
1717 struct frame_info
*fi
;
1721 fprintf_unfiltered (gdb_stdlog
,
1722 "{ create_new_frame (addr=%s, pc=%s) ",
1723 hex_string (addr
), hex_string (pc
));
1726 fi
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1728 fi
->next
= create_sentinel_frame (current_program_space
,
1729 get_current_regcache ());
1731 /* Set/update this frame's cached PC value, found in the next frame.
1732 Do this before looking for this frame's unwinder. A sniffer is
1733 very likely to read this, and the corresponding unwinder is
1734 entitled to rely that the PC doesn't magically change. */
1735 fi
->next
->prev_pc
.value
= pc
;
1736 fi
->next
->prev_pc
.status
= CC_VALUE
;
1738 /* We currently assume that frame chain's can't cross spaces. */
1739 fi
->pspace
= fi
->next
->pspace
;
1740 fi
->aspace
= fi
->next
->aspace
;
1742 /* Select/initialize both the unwind function and the frame's type
1744 frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
1747 fi
->this_id
.value
= frame_id_build (addr
, pc
);
1751 fprintf_unfiltered (gdb_stdlog
, "-> ");
1752 fprint_frame (gdb_stdlog
, fi
);
1753 fprintf_unfiltered (gdb_stdlog
, " }\n");
1759 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
1760 innermost frame). Be careful to not fall off the bottom of the
1761 frame chain and onto the sentinel frame. */
1764 get_next_frame (struct frame_info
*this_frame
)
1766 if (this_frame
->level
> 0)
1767 return this_frame
->next
;
1772 /* Return the frame that THIS_FRAME calls. If THIS_FRAME is the
1773 innermost (i.e. current) frame, return the sentinel frame. Thus,
1774 unlike get_next_frame(), NULL will never be returned. */
1777 get_next_frame_sentinel_okay (struct frame_info
*this_frame
)
1779 gdb_assert (this_frame
!= NULL
);
1781 /* Note that, due to the manner in which the sentinel frame is
1782 constructed, this_frame->next still works even when this_frame
1783 is the sentinel frame. But we disallow it here anyway because
1784 calling get_next_frame_sentinel_okay() on the sentinel frame
1785 is likely a coding error. */
1786 gdb_assert (this_frame
!= sentinel_frame
);
1788 return this_frame
->next
;
1791 /* Observer for the target_changed event. */
1794 frame_observer_target_changed (struct target_ops
*target
)
1796 reinit_frame_cache ();
1799 /* Flush the entire frame cache. */
1802 reinit_frame_cache (void)
1804 struct frame_info
*fi
;
1806 /* Tear down all frame caches. */
1807 for (fi
= sentinel_frame
; fi
!= NULL
; fi
= fi
->prev
)
1809 if (fi
->prologue_cache
&& fi
->unwind
->dealloc_cache
)
1810 fi
->unwind
->dealloc_cache (fi
, fi
->prologue_cache
);
1811 if (fi
->base_cache
&& fi
->base
->unwind
->dealloc_cache
)
1812 fi
->base
->unwind
->dealloc_cache (fi
, fi
->base_cache
);
1815 /* Since we can't really be sure what the first object allocated was. */
1816 obstack_free (&frame_cache_obstack
, 0);
1817 obstack_init (&frame_cache_obstack
);
1819 if (sentinel_frame
!= NULL
)
1820 annotate_frames_invalid ();
1822 sentinel_frame
= NULL
; /* Invalidate cache */
1823 select_frame (NULL
);
1824 frame_stash_invalidate ();
1826 fprintf_unfiltered (gdb_stdlog
, "{ reinit_frame_cache () }\n");
1829 /* Find where a register is saved (in memory or another register).
1830 The result of frame_register_unwind is just where it is saved
1831 relative to this particular frame. */
1834 frame_register_unwind_location (struct frame_info
*this_frame
, int regnum
,
1835 int *optimizedp
, enum lval_type
*lvalp
,
1836 CORE_ADDR
*addrp
, int *realnump
)
1838 gdb_assert (this_frame
== NULL
|| this_frame
->level
>= 0);
1840 while (this_frame
!= NULL
)
1844 frame_register_unwind (this_frame
, regnum
, optimizedp
, &unavailable
,
1845 lvalp
, addrp
, realnump
, NULL
);
1850 if (*lvalp
!= lval_register
)
1854 this_frame
= get_next_frame (this_frame
);
1858 /* Called during frame unwinding to remove a previous frame pointer from a
1859 frame passed in ARG. */
1862 remove_prev_frame (void *arg
)
1864 struct frame_info
*this_frame
, *prev_frame
;
1866 this_frame
= (struct frame_info
*) arg
;
1867 prev_frame
= this_frame
->prev
;
1868 gdb_assert (prev_frame
!= NULL
);
1870 prev_frame
->next
= NULL
;
1871 this_frame
->prev
= NULL
;
1874 /* Get the previous raw frame, and check that it is not identical to
1875 same other frame frame already in the chain. If it is, there is
1876 most likely a stack cycle, so we discard it, and mark THIS_FRAME as
1877 outermost, with UNWIND_SAME_ID stop reason. Unlike the other
1878 validity tests, that compare THIS_FRAME and the next frame, we do
1879 this right after creating the previous frame, to avoid ever ending
1880 up with two frames with the same id in the frame chain. */
1882 static struct frame_info
*
1883 get_prev_frame_if_no_cycle (struct frame_info
*this_frame
)
1885 struct frame_info
*prev_frame
;
1886 struct cleanup
*prev_frame_cleanup
;
1888 prev_frame
= get_prev_frame_raw (this_frame
);
1890 /* Don't compute the frame id of the current frame yet. Unwinding
1891 the sentinel frame can fail (e.g., if the thread is gone and we
1892 can't thus read its registers). If we let the cycle detection
1893 code below try to compute a frame ID, then an error thrown from
1894 within the frame ID computation would result in the sentinel
1895 frame as outermost frame, which is bogus. Instead, we'll compute
1896 the current frame's ID lazily in get_frame_id. Note that there's
1897 no point in doing cycle detection when there's only one frame, so
1898 nothing is lost here. */
1899 if (prev_frame
->level
== 0)
1902 /* The cleanup will remove the previous frame that get_prev_frame_raw
1903 linked onto THIS_FRAME. */
1904 prev_frame_cleanup
= make_cleanup (remove_prev_frame
, this_frame
);
1906 compute_frame_id (prev_frame
);
1907 if (!frame_stash_add (prev_frame
))
1909 /* Another frame with the same id was already in the stash. We just
1910 detected a cycle. */
1913 fprintf_unfiltered (gdb_stdlog
, "-> ");
1914 fprint_frame (gdb_stdlog
, NULL
);
1915 fprintf_unfiltered (gdb_stdlog
, " // this frame has same ID }\n");
1917 this_frame
->stop_reason
= UNWIND_SAME_ID
;
1919 prev_frame
->next
= NULL
;
1920 this_frame
->prev
= NULL
;
1924 discard_cleanups (prev_frame_cleanup
);
1928 /* Helper function for get_prev_frame_always, this is called inside a
1929 TRY_CATCH block. Return the frame that called THIS_FRAME or NULL if
1930 there is no such frame. This may throw an exception. */
1932 static struct frame_info
*
1933 get_prev_frame_always_1 (struct frame_info
*this_frame
)
1935 struct gdbarch
*gdbarch
;
1937 gdb_assert (this_frame
!= NULL
);
1938 gdbarch
= get_frame_arch (this_frame
);
1942 fprintf_unfiltered (gdb_stdlog
, "{ get_prev_frame_always (this_frame=");
1943 if (this_frame
!= NULL
)
1944 fprintf_unfiltered (gdb_stdlog
, "%d", this_frame
->level
);
1946 fprintf_unfiltered (gdb_stdlog
, "<NULL>");
1947 fprintf_unfiltered (gdb_stdlog
, ") ");
1950 /* Only try to do the unwind once. */
1951 if (this_frame
->prev_p
)
1955 fprintf_unfiltered (gdb_stdlog
, "-> ");
1956 fprint_frame (gdb_stdlog
, this_frame
->prev
);
1957 fprintf_unfiltered (gdb_stdlog
, " // cached \n");
1959 return this_frame
->prev
;
1962 /* If the frame unwinder hasn't been selected yet, we must do so
1963 before setting prev_p; otherwise the check for misbehaved
1964 sniffers will think that this frame's sniffer tried to unwind
1965 further (see frame_cleanup_after_sniffer). */
1966 if (this_frame
->unwind
== NULL
)
1967 frame_unwind_find_by_frame (this_frame
, &this_frame
->prologue_cache
);
1969 this_frame
->prev_p
= 1;
1970 this_frame
->stop_reason
= UNWIND_NO_REASON
;
1972 /* If we are unwinding from an inline frame, all of the below tests
1973 were already performed when we unwound from the next non-inline
1974 frame. We must skip them, since we can not get THIS_FRAME's ID
1975 until we have unwound all the way down to the previous non-inline
1977 if (get_frame_type (this_frame
) == INLINE_FRAME
)
1978 return get_prev_frame_if_no_cycle (this_frame
);
1980 /* Check that this frame is unwindable. If it isn't, don't try to
1981 unwind to the prev frame. */
1982 this_frame
->stop_reason
1983 = this_frame
->unwind
->stop_reason (this_frame
,
1984 &this_frame
->prologue_cache
);
1986 if (this_frame
->stop_reason
!= UNWIND_NO_REASON
)
1990 enum unwind_stop_reason reason
= this_frame
->stop_reason
;
1992 fprintf_unfiltered (gdb_stdlog
, "-> ");
1993 fprint_frame (gdb_stdlog
, NULL
);
1994 fprintf_unfiltered (gdb_stdlog
, " // %s }\n",
1995 frame_stop_reason_symbol_string (reason
));
2000 /* Check that this frame's ID isn't inner to (younger, below, next)
2001 the next frame. This happens when a frame unwind goes backwards.
2002 This check is valid only if this frame and the next frame are NORMAL.
2003 See the comment at frame_id_inner for details. */
2004 if (get_frame_type (this_frame
) == NORMAL_FRAME
2005 && this_frame
->next
->unwind
->type
== NORMAL_FRAME
2006 && frame_id_inner (get_frame_arch (this_frame
->next
),
2007 get_frame_id (this_frame
),
2008 get_frame_id (this_frame
->next
)))
2010 CORE_ADDR this_pc_in_block
;
2011 struct minimal_symbol
*morestack_msym
;
2012 const char *morestack_name
= NULL
;
2014 /* gcc -fsplit-stack __morestack can continue the stack anywhere. */
2015 this_pc_in_block
= get_frame_address_in_block (this_frame
);
2016 morestack_msym
= lookup_minimal_symbol_by_pc (this_pc_in_block
).minsym
;
2018 morestack_name
= MSYMBOL_LINKAGE_NAME (morestack_msym
);
2019 if (!morestack_name
|| strcmp (morestack_name
, "__morestack") != 0)
2023 fprintf_unfiltered (gdb_stdlog
, "-> ");
2024 fprint_frame (gdb_stdlog
, NULL
);
2025 fprintf_unfiltered (gdb_stdlog
,
2026 " // this frame ID is inner }\n");
2028 this_frame
->stop_reason
= UNWIND_INNER_ID
;
2033 /* Check that this and the next frame do not unwind the PC register
2034 to the same memory location. If they do, then even though they
2035 have different frame IDs, the new frame will be bogus; two
2036 functions can't share a register save slot for the PC. This can
2037 happen when the prologue analyzer finds a stack adjustment, but
2040 This check does assume that the "PC register" is roughly a
2041 traditional PC, even if the gdbarch_unwind_pc method adjusts
2042 it (we do not rely on the value, only on the unwound PC being
2043 dependent on this value). A potential improvement would be
2044 to have the frame prev_pc method and the gdbarch unwind_pc
2045 method set the same lval and location information as
2046 frame_register_unwind. */
2047 if (this_frame
->level
> 0
2048 && gdbarch_pc_regnum (gdbarch
) >= 0
2049 && get_frame_type (this_frame
) == NORMAL_FRAME
2050 && (get_frame_type (this_frame
->next
) == NORMAL_FRAME
2051 || get_frame_type (this_frame
->next
) == INLINE_FRAME
))
2053 int optimized
, realnum
, nrealnum
;
2054 enum lval_type lval
, nlval
;
2055 CORE_ADDR addr
, naddr
;
2057 frame_register_unwind_location (this_frame
,
2058 gdbarch_pc_regnum (gdbarch
),
2059 &optimized
, &lval
, &addr
, &realnum
);
2060 frame_register_unwind_location (get_next_frame (this_frame
),
2061 gdbarch_pc_regnum (gdbarch
),
2062 &optimized
, &nlval
, &naddr
, &nrealnum
);
2064 if ((lval
== lval_memory
&& lval
== nlval
&& addr
== naddr
)
2065 || (lval
== lval_register
&& lval
== nlval
&& realnum
== nrealnum
))
2069 fprintf_unfiltered (gdb_stdlog
, "-> ");
2070 fprint_frame (gdb_stdlog
, NULL
);
2071 fprintf_unfiltered (gdb_stdlog
, " // no saved PC }\n");
2074 this_frame
->stop_reason
= UNWIND_NO_SAVED_PC
;
2075 this_frame
->prev
= NULL
;
2080 return get_prev_frame_if_no_cycle (this_frame
);
2083 /* Return a "struct frame_info" corresponding to the frame that called
2084 THIS_FRAME. Returns NULL if there is no such frame.
2086 Unlike get_prev_frame, this function always tries to unwind the
2090 get_prev_frame_always (struct frame_info
*this_frame
)
2092 struct frame_info
*prev_frame
= NULL
;
2096 prev_frame
= get_prev_frame_always_1 (this_frame
);
2098 CATCH (ex
, RETURN_MASK_ERROR
)
2100 if (ex
.error
== MEMORY_ERROR
)
2102 this_frame
->stop_reason
= UNWIND_MEMORY_ERROR
;
2103 if (ex
.message
!= NULL
)
2108 /* The error needs to live as long as the frame does.
2109 Allocate using stack local STOP_STRING then assign the
2110 pointer to the frame, this allows the STOP_STRING on the
2111 frame to be of type 'const char *'. */
2112 size
= strlen (ex
.message
) + 1;
2113 stop_string
= (char *) frame_obstack_zalloc (size
);
2114 memcpy (stop_string
, ex
.message
, size
);
2115 this_frame
->stop_string
= stop_string
;
2120 throw_exception (ex
);
2127 /* Construct a new "struct frame_info" and link it previous to
2130 static struct frame_info
*
2131 get_prev_frame_raw (struct frame_info
*this_frame
)
2133 struct frame_info
*prev_frame
;
2135 /* Allocate the new frame but do not wire it in to the frame chain.
2136 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
2137 frame->next to pull some fancy tricks (of course such code is, by
2138 definition, recursive). Try to prevent it.
2140 There is no reason to worry about memory leaks, should the
2141 remainder of the function fail. The allocated memory will be
2142 quickly reclaimed when the frame cache is flushed, and the `we've
2143 been here before' check above will stop repeated memory
2144 allocation calls. */
2145 prev_frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
2146 prev_frame
->level
= this_frame
->level
+ 1;
2148 /* For now, assume we don't have frame chains crossing address
2150 prev_frame
->pspace
= this_frame
->pspace
;
2151 prev_frame
->aspace
= this_frame
->aspace
;
2153 /* Don't yet compute ->unwind (and hence ->type). It is computed
2154 on-demand in get_frame_type, frame_register_unwind, and
2157 /* Don't yet compute the frame's ID. It is computed on-demand by
2160 /* The unwound frame ID is validate at the start of this function,
2161 as part of the logic to decide if that frame should be further
2162 unwound, and not here while the prev frame is being created.
2163 Doing this makes it possible for the user to examine a frame that
2164 has an invalid frame ID.
2166 Some very old VAX code noted: [...] For the sake of argument,
2167 suppose that the stack is somewhat trashed (which is one reason
2168 that "info frame" exists). So, return 0 (indicating we don't
2169 know the address of the arglist) if we don't know what frame this
2173 this_frame
->prev
= prev_frame
;
2174 prev_frame
->next
= this_frame
;
2178 fprintf_unfiltered (gdb_stdlog
, "-> ");
2179 fprint_frame (gdb_stdlog
, prev_frame
);
2180 fprintf_unfiltered (gdb_stdlog
, " }\n");
2186 /* Debug routine to print a NULL frame being returned. */
2189 frame_debug_got_null_frame (struct frame_info
*this_frame
,
2194 fprintf_unfiltered (gdb_stdlog
, "{ get_prev_frame (this_frame=");
2195 if (this_frame
!= NULL
)
2196 fprintf_unfiltered (gdb_stdlog
, "%d", this_frame
->level
);
2198 fprintf_unfiltered (gdb_stdlog
, "<NULL>");
2199 fprintf_unfiltered (gdb_stdlog
, ") -> // %s}\n", reason
);
2203 /* Is this (non-sentinel) frame in the "main"() function? */
2206 inside_main_func (struct frame_info
*this_frame
)
2208 struct bound_minimal_symbol msymbol
;
2211 if (symfile_objfile
== 0)
2213 msymbol
= lookup_minimal_symbol (main_name (), NULL
, symfile_objfile
);
2214 if (msymbol
.minsym
== NULL
)
2216 /* Make certain that the code, and not descriptor, address is
2218 maddr
= gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame
),
2219 BMSYMBOL_VALUE_ADDRESS (msymbol
),
2221 return maddr
== get_frame_func (this_frame
);
2224 /* Test whether THIS_FRAME is inside the process entry point function. */
2227 inside_entry_func (struct frame_info
*this_frame
)
2229 CORE_ADDR entry_point
;
2231 if (!entry_point_address_query (&entry_point
))
2234 return get_frame_func (this_frame
) == entry_point
;
2237 /* Return a structure containing various interesting information about
2238 the frame that called THIS_FRAME. Returns NULL if there is entier
2239 no such frame or the frame fails any of a set of target-independent
2240 condition that should terminate the frame chain (e.g., as unwinding
2243 This function should not contain target-dependent tests, such as
2244 checking whether the program-counter is zero. */
2247 get_prev_frame (struct frame_info
*this_frame
)
2252 /* There is always a frame. If this assertion fails, suspect that
2253 something should be calling get_selected_frame() or
2254 get_current_frame(). */
2255 gdb_assert (this_frame
!= NULL
);
2257 /* If this_frame is the current frame, then compute and stash
2258 its frame id prior to fetching and computing the frame id of the
2259 previous frame. Otherwise, the cycle detection code in
2260 get_prev_frame_if_no_cycle() will not work correctly. When
2261 get_frame_id() is called later on, an assertion error will
2262 be triggered in the event of a cycle between the current
2263 frame and its previous frame. */
2264 if (this_frame
->level
== 0)
2265 get_frame_id (this_frame
);
2267 frame_pc_p
= get_frame_pc_if_available (this_frame
, &frame_pc
);
2269 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
2270 sense to stop unwinding at a dummy frame. One place where a dummy
2271 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
2272 pcsqh register (space register for the instruction at the head of the
2273 instruction queue) cannot be written directly; the only way to set it
2274 is to branch to code that is in the target space. In order to implement
2275 frame dummies on HPUX, the called function is made to jump back to where
2276 the inferior was when the user function was called. If gdb was inside
2277 the main function when we created the dummy frame, the dummy frame will
2278 point inside the main function. */
2279 if (this_frame
->level
>= 0
2280 && get_frame_type (this_frame
) == NORMAL_FRAME
2281 && !backtrace_past_main
2283 && inside_main_func (this_frame
))
2284 /* Don't unwind past main(). Note, this is done _before_ the
2285 frame has been marked as previously unwound. That way if the
2286 user later decides to enable unwinds past main(), that will
2287 automatically happen. */
2289 frame_debug_got_null_frame (this_frame
, "inside main func");
2293 /* If the user's backtrace limit has been exceeded, stop. We must
2294 add two to the current level; one of those accounts for backtrace_limit
2295 being 1-based and the level being 0-based, and the other accounts for
2296 the level of the new frame instead of the level of the current
2298 if (this_frame
->level
+ 2 > backtrace_limit
)
2300 frame_debug_got_null_frame (this_frame
, "backtrace limit exceeded");
2304 /* If we're already inside the entry function for the main objfile,
2305 then it isn't valid. Don't apply this test to a dummy frame -
2306 dummy frame PCs typically land in the entry func. Don't apply
2307 this test to the sentinel frame. Sentinel frames should always
2308 be allowed to unwind. */
2309 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
2310 wasn't checking for "main" in the minimal symbols. With that
2311 fixed asm-source tests now stop in "main" instead of halting the
2312 backtrace in weird and wonderful ways somewhere inside the entry
2313 file. Suspect that tests for inside the entry file/func were
2314 added to work around that (now fixed) case. */
2315 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
2316 suggested having the inside_entry_func test use the
2317 inside_main_func() msymbol trick (along with entry_point_address()
2318 I guess) to determine the address range of the start function.
2319 That should provide a far better stopper than the current
2321 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
2322 applied tail-call optimizations to main so that a function called
2323 from main returns directly to the caller of main. Since we don't
2324 stop at main, we should at least stop at the entry point of the
2326 if (this_frame
->level
>= 0
2327 && get_frame_type (this_frame
) == NORMAL_FRAME
2328 && !backtrace_past_entry
2330 && inside_entry_func (this_frame
))
2332 frame_debug_got_null_frame (this_frame
, "inside entry func");
2336 /* Assume that the only way to get a zero PC is through something
2337 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
2338 will never unwind a zero PC. */
2339 if (this_frame
->level
> 0
2340 && (get_frame_type (this_frame
) == NORMAL_FRAME
2341 || get_frame_type (this_frame
) == INLINE_FRAME
)
2342 && get_frame_type (get_next_frame (this_frame
)) == NORMAL_FRAME
2343 && frame_pc_p
&& frame_pc
== 0)
2345 frame_debug_got_null_frame (this_frame
, "zero PC");
2349 return get_prev_frame_always (this_frame
);
2353 get_prev_frame_id_by_id (struct frame_id id
)
2355 struct frame_id prev_id
;
2356 struct frame_info
*frame
;
2358 frame
= frame_find_by_id (id
);
2361 prev_id
= get_frame_id (get_prev_frame (frame
));
2363 prev_id
= null_frame_id
;
2369 get_frame_pc (struct frame_info
*frame
)
2371 gdb_assert (frame
->next
!= NULL
);
2372 return frame_unwind_pc (frame
->next
);
2376 get_frame_pc_if_available (struct frame_info
*frame
, CORE_ADDR
*pc
)
2379 gdb_assert (frame
->next
!= NULL
);
2383 *pc
= frame_unwind_pc (frame
->next
);
2385 CATCH (ex
, RETURN_MASK_ERROR
)
2387 if (ex
.error
== NOT_AVAILABLE_ERROR
)
2390 throw_exception (ex
);
2397 /* Return an address that falls within THIS_FRAME's code block. */
2400 get_frame_address_in_block (struct frame_info
*this_frame
)
2402 /* A draft address. */
2403 CORE_ADDR pc
= get_frame_pc (this_frame
);
2405 struct frame_info
*next_frame
= this_frame
->next
;
2407 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
2408 Normally the resume address is inside the body of the function
2409 associated with THIS_FRAME, but there is a special case: when
2410 calling a function which the compiler knows will never return
2411 (for instance abort), the call may be the very last instruction
2412 in the calling function. The resume address will point after the
2413 call and may be at the beginning of a different function
2416 If THIS_FRAME is a signal frame or dummy frame, then we should
2417 not adjust the unwound PC. For a dummy frame, GDB pushed the
2418 resume address manually onto the stack. For a signal frame, the
2419 OS may have pushed the resume address manually and invoked the
2420 handler (e.g. GNU/Linux), or invoked the trampoline which called
2421 the signal handler - but in either case the signal handler is
2422 expected to return to the trampoline. So in both of these
2423 cases we know that the resume address is executable and
2424 related. So we only need to adjust the PC if THIS_FRAME
2425 is a normal function.
2427 If the program has been interrupted while THIS_FRAME is current,
2428 then clearly the resume address is inside the associated
2429 function. There are three kinds of interruption: debugger stop
2430 (next frame will be SENTINEL_FRAME), operating system
2431 signal or exception (next frame will be SIGTRAMP_FRAME),
2432 or debugger-induced function call (next frame will be
2433 DUMMY_FRAME). So we only need to adjust the PC if
2434 NEXT_FRAME is a normal function.
2436 We check the type of NEXT_FRAME first, since it is already
2437 known; frame type is determined by the unwinder, and since
2438 we have THIS_FRAME we've already selected an unwinder for
2441 If the next frame is inlined, we need to keep going until we find
2442 the real function - for instance, if a signal handler is invoked
2443 while in an inlined function, then the code address of the
2444 "calling" normal function should not be adjusted either. */
2446 while (get_frame_type (next_frame
) == INLINE_FRAME
)
2447 next_frame
= next_frame
->next
;
2449 if ((get_frame_type (next_frame
) == NORMAL_FRAME
2450 || get_frame_type (next_frame
) == TAILCALL_FRAME
)
2451 && (get_frame_type (this_frame
) == NORMAL_FRAME
2452 || get_frame_type (this_frame
) == TAILCALL_FRAME
2453 || get_frame_type (this_frame
) == INLINE_FRAME
))
2460 get_frame_address_in_block_if_available (struct frame_info
*this_frame
,
2466 *pc
= get_frame_address_in_block (this_frame
);
2468 CATCH (ex
, RETURN_MASK_ERROR
)
2470 if (ex
.error
== NOT_AVAILABLE_ERROR
)
2472 throw_exception (ex
);
2480 find_frame_sal (frame_info
*frame
)
2482 struct frame_info
*next_frame
;
2486 /* If the next frame represents an inlined function call, this frame's
2487 sal is the "call site" of that inlined function, which can not
2488 be inferred from get_frame_pc. */
2489 next_frame
= get_next_frame (frame
);
2490 if (frame_inlined_callees (frame
) > 0)
2495 sym
= get_frame_function (next_frame
);
2497 sym
= inline_skipped_symbol (inferior_ptid
);
2499 /* If frame is inline, it certainly has symbols. */
2502 symtab_and_line sal
;
2503 if (SYMBOL_LINE (sym
) != 0)
2505 sal
.symtab
= symbol_symtab (sym
);
2506 sal
.line
= SYMBOL_LINE (sym
);
2509 /* If the symbol does not have a location, we don't know where
2510 the call site is. Do not pretend to. This is jarring, but
2511 we can't do much better. */
2512 sal
.pc
= get_frame_pc (frame
);
2514 sal
.pspace
= get_frame_program_space (frame
);
2518 /* If FRAME is not the innermost frame, that normally means that
2519 FRAME->pc points at the return instruction (which is *after* the
2520 call instruction), and we want to get the line containing the
2521 call (because the call is where the user thinks the program is).
2522 However, if the next frame is either a SIGTRAMP_FRAME or a
2523 DUMMY_FRAME, then the next frame will contain a saved interrupt
2524 PC and such a PC indicates the current (rather than next)
2525 instruction/line, consequently, for such cases, want to get the
2526 line containing fi->pc. */
2527 if (!get_frame_pc_if_available (frame
, &pc
))
2530 notcurrent
= (pc
!= get_frame_address_in_block (frame
));
2531 return find_pc_line (pc
, notcurrent
);
2534 /* Per "frame.h", return the ``address'' of the frame. Code should
2535 really be using get_frame_id(). */
2537 get_frame_base (struct frame_info
*fi
)
2539 return get_frame_id (fi
).stack_addr
;
2542 /* High-level offsets into the frame. Used by the debug info. */
2545 get_frame_base_address (struct frame_info
*fi
)
2547 if (get_frame_type (fi
) != NORMAL_FRAME
)
2549 if (fi
->base
== NULL
)
2550 fi
->base
= frame_base_find_by_frame (fi
);
2551 /* Sneaky: If the low-level unwind and high-level base code share a
2552 common unwinder, let them share the prologue cache. */
2553 if (fi
->base
->unwind
== fi
->unwind
)
2554 return fi
->base
->this_base (fi
, &fi
->prologue_cache
);
2555 return fi
->base
->this_base (fi
, &fi
->base_cache
);
2559 get_frame_locals_address (struct frame_info
*fi
)
2561 if (get_frame_type (fi
) != NORMAL_FRAME
)
2563 /* If there isn't a frame address method, find it. */
2564 if (fi
->base
== NULL
)
2565 fi
->base
= frame_base_find_by_frame (fi
);
2566 /* Sneaky: If the low-level unwind and high-level base code share a
2567 common unwinder, let them share the prologue cache. */
2568 if (fi
->base
->unwind
== fi
->unwind
)
2569 return fi
->base
->this_locals (fi
, &fi
->prologue_cache
);
2570 return fi
->base
->this_locals (fi
, &fi
->base_cache
);
2574 get_frame_args_address (struct frame_info
*fi
)
2576 if (get_frame_type (fi
) != NORMAL_FRAME
)
2578 /* If there isn't a frame address method, find it. */
2579 if (fi
->base
== NULL
)
2580 fi
->base
= frame_base_find_by_frame (fi
);
2581 /* Sneaky: If the low-level unwind and high-level base code share a
2582 common unwinder, let them share the prologue cache. */
2583 if (fi
->base
->unwind
== fi
->unwind
)
2584 return fi
->base
->this_args (fi
, &fi
->prologue_cache
);
2585 return fi
->base
->this_args (fi
, &fi
->base_cache
);
2588 /* Return true if the frame unwinder for frame FI is UNWINDER; false
2592 frame_unwinder_is (struct frame_info
*fi
, const struct frame_unwind
*unwinder
)
2594 if (fi
->unwind
== NULL
)
2595 frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
2596 return fi
->unwind
== unwinder
;
2599 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
2600 or -1 for a NULL frame. */
2603 frame_relative_level (struct frame_info
*fi
)
2612 get_frame_type (struct frame_info
*frame
)
2614 if (frame
->unwind
== NULL
)
2615 /* Initialize the frame's unwinder because that's what
2616 provides the frame's type. */
2617 frame_unwind_find_by_frame (frame
, &frame
->prologue_cache
);
2618 return frame
->unwind
->type
;
2621 struct program_space
*
2622 get_frame_program_space (struct frame_info
*frame
)
2624 return frame
->pspace
;
2627 struct program_space
*
2628 frame_unwind_program_space (struct frame_info
*this_frame
)
2630 gdb_assert (this_frame
);
2632 /* This is really a placeholder to keep the API consistent --- we
2633 assume for now that we don't have frame chains crossing
2635 return this_frame
->pspace
;
2638 const address_space
*
2639 get_frame_address_space (struct frame_info
*frame
)
2641 return frame
->aspace
;
2644 /* Memory access methods. */
2647 get_frame_memory (struct frame_info
*this_frame
, CORE_ADDR addr
,
2648 gdb_byte
*buf
, int len
)
2650 read_memory (addr
, buf
, len
);
2654 get_frame_memory_signed (struct frame_info
*this_frame
, CORE_ADDR addr
,
2657 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2658 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
2660 return read_memory_integer (addr
, len
, byte_order
);
2664 get_frame_memory_unsigned (struct frame_info
*this_frame
, CORE_ADDR addr
,
2667 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2668 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
2670 return read_memory_unsigned_integer (addr
, len
, byte_order
);
2674 safe_frame_unwind_memory (struct frame_info
*this_frame
,
2675 CORE_ADDR addr
, gdb_byte
*buf
, int len
)
2677 /* NOTE: target_read_memory returns zero on success! */
2678 return !target_read_memory (addr
, buf
, len
);
2681 /* Architecture methods. */
2684 get_frame_arch (struct frame_info
*this_frame
)
2686 return frame_unwind_arch (this_frame
->next
);
2690 frame_unwind_arch (struct frame_info
*next_frame
)
2692 if (!next_frame
->prev_arch
.p
)
2694 struct gdbarch
*arch
;
2696 if (next_frame
->unwind
== NULL
)
2697 frame_unwind_find_by_frame (next_frame
, &next_frame
->prologue_cache
);
2699 if (next_frame
->unwind
->prev_arch
!= NULL
)
2700 arch
= next_frame
->unwind
->prev_arch (next_frame
,
2701 &next_frame
->prologue_cache
);
2703 arch
= get_frame_arch (next_frame
);
2705 next_frame
->prev_arch
.arch
= arch
;
2706 next_frame
->prev_arch
.p
= 1;
2708 fprintf_unfiltered (gdb_stdlog
,
2709 "{ frame_unwind_arch (next_frame=%d) -> %s }\n",
2711 gdbarch_bfd_arch_info (arch
)->printable_name
);
2714 return next_frame
->prev_arch
.arch
;
2718 frame_unwind_caller_arch (struct frame_info
*next_frame
)
2720 next_frame
= skip_artificial_frames (next_frame
);
2722 /* We must have a non-artificial frame. The caller is supposed to check
2723 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
2725 gdb_assert (next_frame
!= NULL
);
2727 return frame_unwind_arch (next_frame
);
2730 /* Gets the language of FRAME. */
2733 get_frame_language (struct frame_info
*frame
)
2738 gdb_assert (frame
!= NULL
);
2740 /* We determine the current frame language by looking up its
2741 associated symtab. To retrieve this symtab, we use the frame
2742 PC. However we cannot use the frame PC as is, because it
2743 usually points to the instruction following the "call", which
2744 is sometimes the first instruction of another function. So
2745 we rely on get_frame_address_in_block(), it provides us with
2746 a PC that is guaranteed to be inside the frame's code
2751 pc
= get_frame_address_in_block (frame
);
2754 CATCH (ex
, RETURN_MASK_ERROR
)
2756 if (ex
.error
!= NOT_AVAILABLE_ERROR
)
2757 throw_exception (ex
);
2763 struct compunit_symtab
*cust
= find_pc_compunit_symtab (pc
);
2766 return compunit_language (cust
);
2769 return language_unknown
;
2772 /* Stack pointer methods. */
2775 get_frame_sp (struct frame_info
*this_frame
)
2777 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2779 /* Normality - an architecture that provides a way of obtaining any
2780 frame inner-most address. */
2781 if (gdbarch_unwind_sp_p (gdbarch
))
2782 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
2783 operate on THIS_FRAME now. */
2784 return gdbarch_unwind_sp (gdbarch
, this_frame
->next
);
2785 /* Now things are really are grim. Hope that the value returned by
2786 the gdbarch_sp_regnum register is meaningful. */
2787 if (gdbarch_sp_regnum (gdbarch
) >= 0)
2788 return get_frame_register_unsigned (this_frame
,
2789 gdbarch_sp_regnum (gdbarch
));
2790 internal_error (__FILE__
, __LINE__
, _("Missing unwind SP method"));
2793 /* Return the reason why we can't unwind past FRAME. */
2795 enum unwind_stop_reason
2796 get_frame_unwind_stop_reason (struct frame_info
*frame
)
2798 /* Fill-in STOP_REASON. */
2799 get_prev_frame_always (frame
);
2800 gdb_assert (frame
->prev_p
);
2802 return frame
->stop_reason
;
2805 /* Return a string explaining REASON. */
2808 unwind_stop_reason_to_string (enum unwind_stop_reason reason
)
2812 #define SET(name, description) \
2813 case name: return _(description);
2814 #include "unwind_stop_reasons.def"
2818 internal_error (__FILE__
, __LINE__
,
2819 "Invalid frame stop reason");
2824 frame_stop_reason_string (struct frame_info
*fi
)
2826 gdb_assert (fi
->prev_p
);
2827 gdb_assert (fi
->prev
== NULL
);
2829 /* Return the specific string if we have one. */
2830 if (fi
->stop_string
!= NULL
)
2831 return fi
->stop_string
;
2833 /* Return the generic string if we have nothing better. */
2834 return unwind_stop_reason_to_string (fi
->stop_reason
);
2837 /* Return the enum symbol name of REASON as a string, to use in debug
2841 frame_stop_reason_symbol_string (enum unwind_stop_reason reason
)
2845 #define SET(name, description) \
2846 case name: return #name;
2847 #include "unwind_stop_reasons.def"
2851 internal_error (__FILE__
, __LINE__
,
2852 "Invalid frame stop reason");
2856 /* Clean up after a failed (wrong unwinder) attempt to unwind past
2860 frame_cleanup_after_sniffer (struct frame_info
*frame
)
2862 /* The sniffer should not allocate a prologue cache if it did not
2863 match this frame. */
2864 gdb_assert (frame
->prologue_cache
== NULL
);
2866 /* No sniffer should extend the frame chain; sniff based on what is
2868 gdb_assert (!frame
->prev_p
);
2870 /* The sniffer should not check the frame's ID; that's circular. */
2871 gdb_assert (!frame
->this_id
.p
);
2873 /* Clear cached fields dependent on the unwinder.
2875 The previous PC is independent of the unwinder, but the previous
2876 function is not (see get_frame_address_in_block). */
2877 frame
->prev_func
.p
= 0;
2878 frame
->prev_func
.addr
= 0;
2880 /* Discard the unwinder last, so that we can easily find it if an assertion
2881 in this function triggers. */
2882 frame
->unwind
= NULL
;
2885 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
2886 If sniffing fails, the caller should be sure to call
2887 frame_cleanup_after_sniffer. */
2890 frame_prepare_for_sniffer (struct frame_info
*frame
,
2891 const struct frame_unwind
*unwind
)
2893 gdb_assert (frame
->unwind
== NULL
);
2894 frame
->unwind
= unwind
;
2897 static struct cmd_list_element
*set_backtrace_cmdlist
;
2898 static struct cmd_list_element
*show_backtrace_cmdlist
;
2901 set_backtrace_cmd (const char *args
, int from_tty
)
2903 help_list (set_backtrace_cmdlist
, "set backtrace ", all_commands
,
2908 show_backtrace_cmd (const char *args
, int from_tty
)
2910 cmd_show_list (show_backtrace_cmdlist
, from_tty
, "");
2914 _initialize_frame (void)
2916 obstack_init (&frame_cache_obstack
);
2918 frame_stash_create ();
2920 gdb::observers::target_changed
.attach (frame_observer_target_changed
);
2922 add_prefix_cmd ("backtrace", class_maintenance
, set_backtrace_cmd
, _("\
2923 Set backtrace specific variables.\n\
2924 Configure backtrace variables such as the backtrace limit"),
2925 &set_backtrace_cmdlist
, "set backtrace ",
2926 0/*allow-unknown*/, &setlist
);
2927 add_prefix_cmd ("backtrace", class_maintenance
, show_backtrace_cmd
, _("\
2928 Show backtrace specific variables\n\
2929 Show backtrace variables such as the backtrace limit"),
2930 &show_backtrace_cmdlist
, "show backtrace ",
2931 0/*allow-unknown*/, &showlist
);
2933 add_setshow_boolean_cmd ("past-main", class_obscure
,
2934 &backtrace_past_main
, _("\
2935 Set whether backtraces should continue past \"main\"."), _("\
2936 Show whether backtraces should continue past \"main\"."), _("\
2937 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
2938 the backtrace at \"main\". Set this variable if you need to see the rest\n\
2939 of the stack trace."),
2941 show_backtrace_past_main
,
2942 &set_backtrace_cmdlist
,
2943 &show_backtrace_cmdlist
);
2945 add_setshow_boolean_cmd ("past-entry", class_obscure
,
2946 &backtrace_past_entry
, _("\
2947 Set whether backtraces should continue past the entry point of a program."),
2949 Show whether backtraces should continue past the entry point of a program."),
2951 Normally there are no callers beyond the entry point of a program, so GDB\n\
2952 will terminate the backtrace there. Set this variable if you need to see\n\
2953 the rest of the stack trace."),
2955 show_backtrace_past_entry
,
2956 &set_backtrace_cmdlist
,
2957 &show_backtrace_cmdlist
);
2959 add_setshow_uinteger_cmd ("limit", class_obscure
,
2960 &backtrace_limit
, _("\
2961 Set an upper bound on the number of backtrace levels."), _("\
2962 Show the upper bound on the number of backtrace levels."), _("\
2963 No more than the specified number of frames can be displayed or examined.\n\
2964 Literal \"unlimited\" or zero means no limit."),
2966 show_backtrace_limit
,
2967 &set_backtrace_cmdlist
,
2968 &show_backtrace_cmdlist
);
2970 /* Debug this files internals. */
2971 add_setshow_zuinteger_cmd ("frame", class_maintenance
, &frame_debug
, _("\
2972 Set frame debugging."), _("\
2973 Show frame debugging."), _("\
2974 When non-zero, frame specific internal debugging is enabled."),
2977 &setdebuglist
, &showdebuglist
);