1 /* Cache and manage frames for GDB, the GNU debugger.
3 Copyright (C) 1986-2023 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/>. */
26 #include "user-regs.h"
27 #include "gdbsupport/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"
45 #include "cli/cli-option.h"
46 #include "dwarf2/loc.h"
48 /* The sentinel frame terminates the innermost end of the frame chain.
49 If unwound, it returns the information needed to construct an
52 The current frame, which is the innermost frame, can be found at
55 This is an optimization to be able to find the sentinel frame quickly,
56 it could otherwise be found in the frame cache. */
58 static frame_info
*sentinel_frame
;
60 /* Number of calls to reinit_frame_cache. */
61 static unsigned int frame_cache_generation
= 0;
66 get_frame_cache_generation ()
68 return frame_cache_generation
;
71 /* The values behind the global "set backtrace ..." settings. */
72 set_backtrace_options user_set_backtrace_options
;
74 static frame_info_ptr
get_prev_frame_raw (frame_info_ptr this_frame
);
75 static const char *frame_stop_reason_symbol_string (enum unwind_stop_reason reason
);
76 static frame_info_ptr
create_new_frame (frame_id id
);
78 /* Status of some values cached in the frame_info object. */
80 enum cached_copy_status
82 /* Value is unknown. */
85 /* We have a value. */
88 /* Value was not saved. */
91 /* Value is unavailable. */
95 enum class frame_id_status
97 /* Frame id is not computed. */
100 /* Frame id is being computed (compute_frame_id is active). */
103 /* Frame id has been computed. */
107 /* We keep a cache of stack frames, each of which is a "struct
108 frame_info". The innermost one gets allocated (in
109 wait_for_inferior) each time the inferior stops; sentinel_frame
110 points to it. Additional frames get allocated (in get_prev_frame)
111 as needed, and are chained through the next and prev fields. Any
112 time that the frame cache becomes invalid (most notably when we
113 execute something, but also if we change how we interpret the
114 frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything
115 which reads new symbols)), we should call reinit_frame_cache. */
119 /* Return a string representation of this frame. */
120 std::string
to_string () const;
122 /* Level of this frame. The inner-most (youngest) frame is at level
123 0. As you move towards the outer-most (oldest) frame, the level
124 increases. This is a cached value. It could just as easily be
125 computed by counting back from the selected frame to the inner
127 /* NOTE: cagney/2002-04-05: Perhaps a level of ``-1'' should be
128 reserved to indicate a bogus frame - one that has been created
129 just to keep GDB happy (GDB always needs a frame). For the
130 moment leave this as speculation. */
133 /* The frame's program space. */
134 struct program_space
*pspace
;
136 /* The frame's address space. */
137 const address_space
*aspace
;
139 /* The frame's low-level unwinder and corresponding cache. The
140 low-level unwinder is responsible for unwinding register values
141 for the previous frame. The low-level unwind methods are
142 selected based on the presence, or otherwise, of register unwind
143 information such as CFI. */
144 void *prologue_cache
;
145 const struct frame_unwind
*unwind
;
147 /* Cached copy of the previous frame's architecture. */
151 struct gdbarch
*arch
;
154 /* Cached copy of the previous frame's resume address. */
156 cached_copy_status status
;
157 /* Did VALUE require unmasking when being read. */
162 /* Cached copy of the previous frame's function address. */
166 cached_copy_status status
;
169 /* This frame's ID. */
173 struct frame_id value
;
176 /* The frame's high-level base methods, and corresponding cache.
177 The high level base methods are selected based on the frame's
179 const struct frame_base
*base
;
182 /* Pointers to the next (down, inner, younger) and previous (up,
183 outer, older) frame_info's in the frame cache. */
184 struct frame_info
*next
; /* down, inner, younger */
186 struct frame_info
*prev
; /* up, outer, older */
188 /* The reason why we could not set PREV, or UNWIND_NO_REASON if we
189 could. Only valid when PREV_P is set. */
190 enum unwind_stop_reason stop_reason
;
192 /* A frame specific string describing the STOP_REASON in more detail.
193 Only valid when PREV_P is set, but even then may still be NULL. */
194 const char *stop_string
;
200 set_frame_previous_pc_masked (frame_info_ptr frame
)
202 frame
->prev_pc
.masked
= true;
208 get_frame_pc_masked (frame_info_ptr frame
)
210 gdb_assert (frame
->next
!= nullptr);
211 gdb_assert (frame
->next
->prev_pc
.status
== CC_VALUE
);
213 return frame
->next
->prev_pc
.masked
;
216 /* A frame stash used to speed up frame lookups. Create a hash table
217 to stash frames previously accessed from the frame cache for
218 quicker subsequent retrieval. The hash table is emptied whenever
219 the frame cache is invalidated. */
221 static htab_t frame_stash
;
223 /* Internal function to calculate a hash from the frame_id addresses,
224 using as many valid addresses as possible. Frames below level 0
225 are not stored in the hash table. */
228 frame_addr_hash (const void *ap
)
230 const frame_info
*frame
= (const frame_info
*) ap
;
231 const struct frame_id f_id
= frame
->this_id
.value
;
234 gdb_assert (f_id
.stack_status
!= FID_STACK_INVALID
236 || f_id
.special_addr_p
);
238 if (f_id
.stack_status
== FID_STACK_VALID
)
239 hash
= iterative_hash (&f_id
.stack_addr
,
240 sizeof (f_id
.stack_addr
), hash
);
241 if (f_id
.code_addr_p
)
242 hash
= iterative_hash (&f_id
.code_addr
,
243 sizeof (f_id
.code_addr
), hash
);
244 if (f_id
.special_addr_p
)
245 hash
= iterative_hash (&f_id
.special_addr
,
246 sizeof (f_id
.special_addr
), hash
);
248 char user_created_p
= f_id
.user_created_p
;
249 hash
= iterative_hash (&user_created_p
, sizeof (user_created_p
), hash
);
254 /* Internal equality function for the hash table. This function
255 defers equality operations to frame_id::operator==. */
258 frame_addr_hash_eq (const void *a
, const void *b
)
260 const frame_info
*f_entry
= (const frame_info
*) a
;
261 const frame_info
*f_element
= (const frame_info
*) b
;
263 return f_entry
->this_id
.value
== f_element
->this_id
.value
;
266 /* Deletion function for the frame cache hash table. */
269 frame_info_del (frame_info
*frame
)
271 if (frame
->prologue_cache
!= nullptr
272 && frame
->unwind
->dealloc_cache
!= nullptr)
273 frame
->unwind
->dealloc_cache (frame
, frame
->prologue_cache
);
275 if (frame
->base_cache
!= nullptr
276 && frame
->base
->unwind
->dealloc_cache
!= nullptr)
277 frame
->base
->unwind
->dealloc_cache (frame
, frame
->base_cache
);
280 /* Internal function to create the frame_stash hash table. 100 seems
281 to be a good compromise to start the hash table at. */
284 frame_stash_create (void)
286 frame_stash
= htab_create
287 (100, frame_addr_hash
, frame_addr_hash_eq
,
290 auto frame
= static_cast<frame_info
*> (p
);
291 frame_info_del (frame
);
295 /* Internal function to add a frame to the frame_stash hash table.
296 Returns false if a frame with the same ID was already stashed, true
300 frame_stash_add (frame_info
*frame
)
302 /* Valid frame levels are -1 (sentinel frames) and above. */
303 gdb_assert (frame
->level
>= -1);
305 frame_info
**slot
= (frame_info
**) htab_find_slot (frame_stash
,
308 /* If we already have a frame in the stack with the same id, we
309 either have a stack cycle (corrupted stack?), or some bug
310 elsewhere in GDB. In any case, ignore the duplicate and return
311 an indication to the caller. */
312 if (*slot
!= nullptr)
319 /* Internal function to search the frame stash for an entry with the
320 given frame ID. If found, return that frame. Otherwise return
323 static frame_info_ptr
324 frame_stash_find (struct frame_id id
)
326 struct frame_info dummy
;
329 dummy
.this_id
.value
= id
;
330 frame
= (frame_info
*) htab_find (frame_stash
, &dummy
);
331 return frame_info_ptr (frame
);
334 /* Internal function to invalidate the frame stash by removing all
335 entries in it. This only occurs when the frame cache is
339 frame_stash_invalidate (void)
341 htab_empty (frame_stash
);
345 scoped_restore_selected_frame::scoped_restore_selected_frame ()
347 m_lang
= current_language
->la_language
;
348 save_selected_frame (&m_fid
, &m_level
);
352 scoped_restore_selected_frame::~scoped_restore_selected_frame ()
354 restore_selected_frame (m_fid
, m_level
);
355 set_language (m_lang
);
358 /* Flag to control debugging. */
363 show_frame_debug (struct ui_file
*file
, int from_tty
,
364 struct cmd_list_element
*c
, const char *value
)
366 gdb_printf (file
, _("Frame debugging is %s.\n"), value
);
369 /* Implementation of "show backtrace past-main". */
372 show_backtrace_past_main (struct ui_file
*file
, int from_tty
,
373 struct cmd_list_element
*c
, const char *value
)
376 _("Whether backtraces should "
377 "continue past \"main\" is %s.\n"),
381 /* Implementation of "show backtrace past-entry". */
384 show_backtrace_past_entry (struct ui_file
*file
, int from_tty
,
385 struct cmd_list_element
*c
, const char *value
)
387 gdb_printf (file
, _("Whether backtraces should continue past the "
388 "entry point of a program is %s.\n"),
392 /* Implementation of "show backtrace limit". */
395 show_backtrace_limit (struct ui_file
*file
, int from_tty
,
396 struct cmd_list_element
*c
, const char *value
)
399 _("An upper bound on the number "
400 "of backtrace levels is %s.\n"),
407 frame_id::to_string () const
409 const struct frame_id
&id
= *this;
411 std::string res
= "{";
413 if (id
.stack_status
== FID_STACK_INVALID
)
415 else if (id
.stack_status
== FID_STACK_UNAVAILABLE
)
416 res
+= "stack=<unavailable>";
417 else if (id
.stack_status
== FID_STACK_SENTINEL
)
418 res
+= "stack=<sentinel>";
419 else if (id
.stack_status
== FID_STACK_OUTER
)
420 res
+= "stack=<outer>";
422 res
+= std::string ("stack=") + hex_string (id
.stack_addr
);
424 /* Helper function to format 'N=A' if P is true, otherwise '!N'. */
425 auto field_to_string
= [] (const char *n
, bool p
, CORE_ADDR a
) -> std::string
428 return std::string (n
) + "=" + core_addr_to_string (a
);
430 return std::string ("!") + std::string (n
);
433 res
+= (std::string (",")
434 + field_to_string ("code", id
.code_addr_p
, id
.code_addr
)
436 + field_to_string ("special", id
.special_addr_p
, id
.special_addr
));
438 if (id
.artificial_depth
)
439 res
+= ",artificial=" + std::to_string (id
.artificial_depth
);
447 frame_type_str (frame_type type
)
452 return "NORMAL_FRAME";
455 return "DUMMY_FRAME";
458 return "INLINE_FRAME";
461 return "TAILCALL_FRAME";
464 return "SIGTRAMP_FRAME";
470 return "SENTINEL_FRAME";
473 return "<unknown type>";
477 /* See struct frame_info. */
480 frame_info::to_string () const
482 const frame_info
*fi
= this;
486 res
+= string_printf ("{level=%d,", fi
->level
);
488 if (fi
->unwind
!= NULL
)
489 res
+= string_printf ("type=%s,", frame_type_str (fi
->unwind
->type
));
491 res
+= "type=<unknown>,";
493 if (fi
->unwind
!= NULL
)
494 res
+= string_printf ("unwinder=\"%s\",", fi
->unwind
->name
);
496 res
+= "unwinder=<unknown>,";
498 if (fi
->next
== NULL
|| fi
->next
->prev_pc
.status
== CC_UNKNOWN
)
499 res
+= "pc=<unknown>,";
500 else if (fi
->next
->prev_pc
.status
== CC_VALUE
)
501 res
+= string_printf ("pc=%s%s,", hex_string (fi
->next
->prev_pc
.value
),
502 fi
->next
->prev_pc
.masked
? "[PAC]" : "");
503 else if (fi
->next
->prev_pc
.status
== CC_NOT_SAVED
)
504 res
+= "pc=<not saved>,";
505 else if (fi
->next
->prev_pc
.status
== CC_UNAVAILABLE
)
506 res
+= "pc=<unavailable>,";
508 if (fi
->this_id
.p
== frame_id_status::NOT_COMPUTED
)
509 res
+= "id=<not computed>,";
510 else if (fi
->this_id
.p
== frame_id_status::COMPUTING
)
511 res
+= "id=<computing>,";
513 res
+= string_printf ("id=%s,", fi
->this_id
.value
.to_string ().c_str ());
515 if (fi
->next
!= NULL
&& fi
->next
->prev_func
.status
== CC_VALUE
)
516 res
+= string_printf ("func=%s", hex_string (fi
->next
->prev_func
.addr
));
518 res
+= "func=<unknown>";
525 /* Given FRAME, return the enclosing frame as found in real frames read-in from
526 inferior memory. Skip any previous frames which were made up by GDB.
527 Return FRAME if FRAME is a non-artificial frame.
528 Return NULL if FRAME is the start of an artificial-only chain. */
530 static frame_info_ptr
531 skip_artificial_frames (frame_info_ptr frame
)
533 /* Note we use get_prev_frame_always, and not get_prev_frame. The
534 latter will truncate the frame chain, leading to this function
535 unintentionally returning a null_frame_id (e.g., when the user
536 sets a backtrace limit).
538 Note that for record targets we may get a frame chain that consists
539 of artificial frames only. */
540 while (get_frame_type (frame
) == INLINE_FRAME
541 || get_frame_type (frame
) == TAILCALL_FRAME
)
543 frame
= get_prev_frame_always (frame
);
552 skip_unwritable_frames (frame_info_ptr frame
)
554 while (gdbarch_code_of_frame_writable (get_frame_arch (frame
), frame
) == 0)
556 frame
= get_prev_frame (frame
);
567 skip_tailcall_frames (frame_info_ptr frame
)
569 while (get_frame_type (frame
) == TAILCALL_FRAME
)
571 /* Note that for record targets we may get a frame chain that consists of
572 tailcall frames only. */
573 frame
= get_prev_frame (frame
);
581 /* Compute the frame's uniq ID that can be used to, later, re-find the
585 compute_frame_id (frame_info_ptr fi
)
587 FRAME_SCOPED_DEBUG_ENTER_EXIT
;
589 gdb_assert (fi
->this_id
.p
== frame_id_status::NOT_COMPUTED
);
591 unsigned int entry_generation
= get_frame_cache_generation ();
595 /* Mark this frame's id as "being computed. */
596 fi
->this_id
.p
= frame_id_status::COMPUTING
;
598 frame_debug_printf ("fi=%d", fi
->level
);
600 /* Find the unwinder. */
601 if (fi
->unwind
== NULL
)
602 frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
604 /* Find THIS frame's ID. */
605 /* Default to outermost if no ID is found. */
606 fi
->this_id
.value
= outer_frame_id
;
607 fi
->unwind
->this_id (fi
, &fi
->prologue_cache
, &fi
->this_id
.value
);
608 gdb_assert (frame_id_p (fi
->this_id
.value
));
610 /* Mark this frame's id as "computed". */
611 fi
->this_id
.p
= frame_id_status::COMPUTED
;
613 frame_debug_printf (" -> %s", fi
->this_id
.value
.to_string ().c_str ());
615 catch (const gdb_exception
&ex
)
617 /* On error, revert the frame id status to not computed. If the frame
618 cache generation changed, the frame object doesn't exist anymore, so
620 if (get_frame_cache_generation () == entry_generation
)
621 fi
->this_id
.p
= frame_id_status::NOT_COMPUTED
;
627 /* Return a frame uniq ID that can be used to, later, re-find the
631 get_frame_id (frame_info_ptr fi
)
634 return null_frame_id
;
636 /* It's always invalid to try to get a frame's id while it is being
638 gdb_assert (fi
->this_id
.p
!= frame_id_status::COMPUTING
);
640 if (fi
->this_id
.p
== frame_id_status::NOT_COMPUTED
)
642 /* If we haven't computed the frame id yet, then it must be that
643 this is the current frame. Compute it now, and stash the
644 result. The IDs of other frames are computed as soon as
645 they're created, in order to detect cycles. See
646 get_prev_frame_if_no_cycle. */
647 gdb_assert (fi
->level
== 0);
650 compute_frame_id (fi
);
652 /* Since this is the first frame in the chain, this should
654 bool stashed
= frame_stash_add (fi
.get ());
655 gdb_assert (stashed
);
658 return fi
->this_id
.value
;
662 get_stack_frame_id (frame_info_ptr next_frame
)
664 return get_frame_id (skip_artificial_frames (next_frame
));
668 frame_unwind_caller_id (frame_info_ptr next_frame
)
670 frame_info_ptr this_frame
;
672 /* Use get_prev_frame_always, and not get_prev_frame. The latter
673 will truncate the frame chain, leading to this function
674 unintentionally returning a null_frame_id (e.g., when a caller
675 requests the frame ID of "main()"s caller. */
677 next_frame
= skip_artificial_frames (next_frame
);
678 if (next_frame
== NULL
)
679 return null_frame_id
;
681 this_frame
= get_prev_frame_always (next_frame
);
683 return get_frame_id (skip_artificial_frames (this_frame
));
685 return null_frame_id
;
688 const struct frame_id null_frame_id
= { 0 }; /* All zeros. */
689 const struct frame_id outer_frame_id
= { 0, 0, 0, FID_STACK_OUTER
, 0, 1, 0 };
692 frame_id_build_special (CORE_ADDR stack_addr
, CORE_ADDR code_addr
,
693 CORE_ADDR special_addr
)
695 struct frame_id id
= null_frame_id
;
697 id
.stack_addr
= stack_addr
;
698 id
.stack_status
= FID_STACK_VALID
;
699 id
.code_addr
= code_addr
;
700 id
.code_addr_p
= true;
701 id
.special_addr
= special_addr
;
702 id
.special_addr_p
= true;
709 frame_id_build_unavailable_stack (CORE_ADDR code_addr
)
711 struct frame_id id
= null_frame_id
;
713 id
.stack_status
= FID_STACK_UNAVAILABLE
;
714 id
.code_addr
= code_addr
;
715 id
.code_addr_p
= true;
722 frame_id_build_unavailable_stack_special (CORE_ADDR code_addr
,
723 CORE_ADDR special_addr
)
725 struct frame_id id
= null_frame_id
;
727 id
.stack_status
= FID_STACK_UNAVAILABLE
;
728 id
.code_addr
= code_addr
;
729 id
.code_addr_p
= true;
730 id
.special_addr
= special_addr
;
731 id
.special_addr_p
= true;
736 frame_id_build (CORE_ADDR stack_addr
, CORE_ADDR code_addr
)
738 struct frame_id id
= null_frame_id
;
740 id
.stack_addr
= stack_addr
;
741 id
.stack_status
= FID_STACK_VALID
;
742 id
.code_addr
= code_addr
;
743 id
.code_addr_p
= true;
748 frame_id_build_wild (CORE_ADDR stack_addr
)
750 struct frame_id id
= null_frame_id
;
752 id
.stack_addr
= stack_addr
;
753 id
.stack_status
= FID_STACK_VALID
;
760 frame_id_build_sentinel (CORE_ADDR stack_addr
, CORE_ADDR code_addr
)
762 frame_id id
= null_frame_id
;
764 id
.stack_status
= FID_STACK_SENTINEL
;
765 id
.special_addr_p
= 1;
767 if (stack_addr
!= 0 || code_addr
!= 0)
769 /* The purpose of saving these in the sentinel frame ID is to be able to
770 differentiate the IDs of several sentinel frames that could exist
771 simultaneously in the frame cache. */
772 id
.stack_addr
= stack_addr
;
773 id
.code_addr
= code_addr
;
781 frame_id_p (frame_id l
)
783 /* The frame is valid iff it has a valid stack address. */
784 bool p
= l
.stack_status
!= FID_STACK_INVALID
;
786 frame_debug_printf ("l=%s -> %d", l
.to_string ().c_str (), p
);
792 frame_id_artificial_p (frame_id l
)
797 return l
.artificial_depth
!= 0;
801 frame_id::operator== (const frame_id
&r
) const
805 if (stack_status
== FID_STACK_INVALID
806 || r
.stack_status
== FID_STACK_INVALID
)
807 /* Like a NaN, if either ID is invalid, the result is false.
808 Note that a frame ID is invalid iff it is the null frame ID. */
810 else if (stack_status
!= r
.stack_status
|| stack_addr
!= r
.stack_addr
)
811 /* If .stack addresses are different, the frames are different. */
813 else if (code_addr_p
&& r
.code_addr_p
&& code_addr
!= r
.code_addr
)
814 /* An invalid code addr is a wild card. If .code addresses are
815 different, the frames are different. */
817 else if (special_addr_p
&& r
.special_addr_p
818 && special_addr
!= r
.special_addr
)
819 /* An invalid special addr is a wild card (or unused). Otherwise
820 if special addresses are different, the frames are different. */
822 else if (artificial_depth
!= r
.artificial_depth
)
823 /* If artificial depths are different, the frames must be different. */
825 else if (user_created_p
!= r
.user_created_p
)
828 /* Frames are equal. */
831 frame_debug_printf ("l=%s, r=%s -> %d",
832 to_string ().c_str (), r
.to_string ().c_str (), eq
);
837 /* Safety net to check whether frame ID L should be inner to
838 frame ID R, according to their stack addresses.
840 This method cannot be used to compare arbitrary frames, as the
841 ranges of valid stack addresses may be discontiguous (e.g. due
844 However, it can be used as safety net to discover invalid frame
845 IDs in certain circumstances. Assuming that NEXT is the immediate
846 inner frame to THIS and that NEXT and THIS are both NORMAL frames:
848 * The stack address of NEXT must be inner-than-or-equal to the stack
851 Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind
854 * If NEXT and THIS have different stack addresses, no other frame
855 in the frame chain may have a stack address in between.
857 Therefore, if frame_id_inner (TEST, THIS) holds, but
858 frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer
859 to a valid frame in the frame chain.
861 The sanity checks above cannot be performed when a SIGTRAMP frame
862 is involved, because signal handlers might be executed on a different
863 stack than the stack used by the routine that caused the signal
864 to be raised. This can happen for instance when a thread exceeds
865 its maximum stack size. In this case, certain compilers implement
866 a stack overflow strategy that cause the handler to be run on a
870 frame_id_inner (struct gdbarch
*gdbarch
, struct frame_id l
, struct frame_id r
)
874 if (l
.stack_status
!= FID_STACK_VALID
|| r
.stack_status
!= FID_STACK_VALID
)
875 /* Like NaN, any operation involving an invalid ID always fails.
876 Likewise if either ID has an unavailable stack address. */
878 else if (l
.artificial_depth
> r
.artificial_depth
879 && l
.stack_addr
== r
.stack_addr
880 && l
.code_addr_p
== r
.code_addr_p
881 && l
.special_addr_p
== r
.special_addr_p
882 && l
.special_addr
== r
.special_addr
)
884 /* Same function, different inlined functions. */
885 const struct block
*lb
, *rb
;
887 gdb_assert (l
.code_addr_p
&& r
.code_addr_p
);
889 lb
= block_for_pc (l
.code_addr
);
890 rb
= block_for_pc (r
.code_addr
);
892 if (lb
== NULL
|| rb
== NULL
)
893 /* Something's gone wrong. */
896 /* This will return true if LB and RB are the same block, or
897 if the block with the smaller depth lexically encloses the
898 block with the greater depth. */
899 inner
= rb
->contains (lb
);
902 /* Only return non-zero when strictly inner than. Note that, per
903 comment in "frame.h", there is some fuzz here. Frameless
904 functions are not strictly inner than (same .stack but
905 different .code and/or .special address). */
906 inner
= gdbarch_inner_than (gdbarch
, l
.stack_addr
, r
.stack_addr
);
908 frame_debug_printf ("is l=%s inner than r=%s? %d",
909 l
.to_string ().c_str (), r
.to_string ().c_str (),
916 frame_find_by_id (struct frame_id id
)
918 frame_info_ptr frame
, prev_frame
;
920 /* ZERO denotes the null frame, let the caller decide what to do
921 about it. Should it instead return get_current_frame()? */
922 if (!frame_id_p (id
))
925 /* Check for the sentinel frame. */
926 if (id
== frame_id_build_sentinel (0, 0))
927 return frame_info_ptr (sentinel_frame
);
929 /* Try using the frame stash first. Finding it there removes the need
930 to perform the search by looping over all frames, which can be very
931 CPU-intensive if the number of frames is very high (the loop is O(n)
932 and get_prev_frame performs a series of checks that are relatively
933 expensive). This optimization is particularly useful when this function
934 is called from another function (such as value_fetch_lazy, case
935 val->lval () == lval_register) which already loops over all frames,
936 making the overall behavior O(n^2). */
937 frame
= frame_stash_find (id
);
941 for (frame
= get_current_frame (); ; frame
= prev_frame
)
943 struct frame_id self
= get_frame_id (frame
);
946 /* An exact match. */
949 prev_frame
= get_prev_frame (frame
);
953 /* As a safety net to avoid unnecessary backtracing while trying
954 to find an invalid ID, we check for a common situation where
955 we can detect from comparing stack addresses that no other
956 frame in the current frame chain can have this ID. See the
957 comment at frame_id_inner for details. */
958 if (get_frame_type (frame
) == NORMAL_FRAME
959 && !frame_id_inner (get_frame_arch (frame
), id
, self
)
960 && frame_id_inner (get_frame_arch (prev_frame
), id
,
961 get_frame_id (prev_frame
)))
968 frame_unwind_pc (frame_info_ptr this_frame
)
970 if (this_frame
->prev_pc
.status
== CC_UNKNOWN
)
972 struct gdbarch
*prev_gdbarch
;
976 /* The right way. The `pure' way. The one true way. This
977 method depends solely on the register-unwind code to
978 determine the value of registers in THIS frame, and hence
979 the value of this frame's PC (resume address). A typical
980 implementation is no more than:
982 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf);
983 return extract_unsigned_integer (buf, size of ISA_PC_REGNUM);
985 Note: this method is very heavily dependent on a correct
986 register-unwind implementation, it pays to fix that
987 method first; this method is frame type agnostic, since
988 it only deals with register values, it works with any
989 frame. This is all in stark contrast to the old
990 FRAME_SAVED_PC which would try to directly handle all the
991 different ways that a PC could be unwound. */
992 prev_gdbarch
= frame_unwind_arch (this_frame
);
996 pc
= gdbarch_unwind_pc (prev_gdbarch
, this_frame
);
999 catch (const gdb_exception_error
&ex
)
1001 if (ex
.error
== NOT_AVAILABLE_ERROR
)
1003 this_frame
->prev_pc
.status
= CC_UNAVAILABLE
;
1005 frame_debug_printf ("this_frame=%d -> <unavailable>",
1008 else if (ex
.error
== OPTIMIZED_OUT_ERROR
)
1010 this_frame
->prev_pc
.status
= CC_NOT_SAVED
;
1012 frame_debug_printf ("this_frame=%d -> <not saved>",
1021 this_frame
->prev_pc
.value
= pc
;
1022 this_frame
->prev_pc
.status
= CC_VALUE
;
1024 frame_debug_printf ("this_frame=%d -> %s",
1026 hex_string (this_frame
->prev_pc
.value
));
1030 if (this_frame
->prev_pc
.status
== CC_VALUE
)
1031 return this_frame
->prev_pc
.value
;
1032 else if (this_frame
->prev_pc
.status
== CC_UNAVAILABLE
)
1033 throw_error (NOT_AVAILABLE_ERROR
, _("PC not available"));
1034 else if (this_frame
->prev_pc
.status
== CC_NOT_SAVED
)
1035 throw_error (OPTIMIZED_OUT_ERROR
, _("PC not saved"));
1037 internal_error ("unexpected prev_pc status: %d",
1038 (int) this_frame
->prev_pc
.status
);
1042 frame_unwind_caller_pc (frame_info_ptr this_frame
)
1044 this_frame
= skip_artificial_frames (this_frame
);
1046 /* We must have a non-artificial frame. The caller is supposed to check
1047 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
1049 gdb_assert (this_frame
!= NULL
);
1051 return frame_unwind_pc (this_frame
);
1055 get_frame_func_if_available (frame_info_ptr this_frame
, CORE_ADDR
*pc
)
1057 frame_info
*next_frame
= this_frame
->next
;
1059 if (next_frame
->prev_func
.status
== CC_UNKNOWN
)
1061 CORE_ADDR addr_in_block
;
1063 /* Make certain that this, and not the adjacent, function is
1065 if (!get_frame_address_in_block_if_available (this_frame
, &addr_in_block
))
1067 next_frame
->prev_func
.status
= CC_UNAVAILABLE
;
1069 frame_debug_printf ("this_frame=%d -> unavailable",
1074 next_frame
->prev_func
.status
= CC_VALUE
;
1075 next_frame
->prev_func
.addr
= get_pc_function_start (addr_in_block
);
1077 frame_debug_printf ("this_frame=%d -> %s",
1079 hex_string (next_frame
->prev_func
.addr
));
1083 if (next_frame
->prev_func
.status
== CC_UNAVAILABLE
)
1090 gdb_assert (next_frame
->prev_func
.status
== CC_VALUE
);
1092 *pc
= next_frame
->prev_func
.addr
;
1098 get_frame_func (frame_info_ptr this_frame
)
1102 if (!get_frame_func_if_available (this_frame
, &pc
))
1103 throw_error (NOT_AVAILABLE_ERROR
, _("PC not available"));
1108 std::unique_ptr
<readonly_detached_regcache
>
1109 frame_save_as_regcache (frame_info_ptr this_frame
)
1111 auto cooked_read
= [this_frame
] (int regnum
, gdb_byte
*buf
)
1113 if (!deprecated_frame_register_read (this_frame
, regnum
, buf
))
1114 return REG_UNAVAILABLE
;
1119 std::unique_ptr
<readonly_detached_regcache
> regcache
1120 (new readonly_detached_regcache (get_frame_arch (this_frame
), cooked_read
));
1126 frame_pop (frame_info_ptr this_frame
)
1128 frame_info_ptr prev_frame
;
1130 if (get_frame_type (this_frame
) == DUMMY_FRAME
)
1132 /* Popping a dummy frame involves restoring more than just registers.
1133 dummy_frame_pop does all the work. */
1134 dummy_frame_pop (get_frame_id (this_frame
), inferior_thread ());
1138 /* Ensure that we have a frame to pop to. */
1139 prev_frame
= get_prev_frame_always (this_frame
);
1142 error (_("Cannot pop the initial frame."));
1144 /* Ignore TAILCALL_FRAME type frames, they were executed already before
1145 entering THISFRAME. */
1146 prev_frame
= skip_tailcall_frames (prev_frame
);
1148 if (prev_frame
== NULL
)
1149 error (_("Cannot find the caller frame."));
1151 /* Make a copy of all the register values unwound from this frame.
1152 Save them in a scratch buffer so that there isn't a race between
1153 trying to extract the old values from the current regcache while
1154 at the same time writing new values into that same cache. */
1155 std::unique_ptr
<readonly_detached_regcache
> scratch
1156 = frame_save_as_regcache (prev_frame
);
1158 /* FIXME: cagney/2003-03-16: It should be possible to tell the
1159 target's register cache that it is about to be hit with a burst
1160 register transfer and that the sequence of register writes should
1161 be batched. The pair target_prepare_to_store() and
1162 target_store_registers() kind of suggest this functionality.
1163 Unfortunately, they don't implement it. Their lack of a formal
1164 definition can lead to targets writing back bogus values
1165 (arguably a bug in the target code mind). */
1166 /* Now copy those saved registers into the current regcache. */
1167 get_thread_regcache (inferior_thread ())->restore (scratch
.get ());
1169 /* We've made right mess of GDB's local state, just discard
1171 reinit_frame_cache ();
1175 frame_register_unwind (frame_info_ptr next_frame
, int regnum
,
1176 int *optimizedp
, int *unavailablep
,
1177 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
1178 int *realnump
, gdb_byte
*bufferp
)
1180 struct value
*value
;
1182 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1183 that the value proper does not need to be fetched. */
1184 gdb_assert (optimizedp
!= NULL
);
1185 gdb_assert (lvalp
!= NULL
);
1186 gdb_assert (addrp
!= NULL
);
1187 gdb_assert (realnump
!= NULL
);
1188 /* gdb_assert (bufferp != NULL); */
1190 value
= frame_unwind_register_value (next_frame
, regnum
);
1192 gdb_assert (value
!= NULL
);
1194 *optimizedp
= value
->optimized_out ();
1195 *unavailablep
= !value
->entirely_available ();
1196 *lvalp
= value
->lval ();
1197 *addrp
= value
->address ();
1198 if (*lvalp
== lval_register
)
1199 *realnump
= VALUE_REGNUM (value
);
1205 if (!*optimizedp
&& !*unavailablep
)
1206 memcpy (bufferp
, value
->contents_all ().data (),
1207 value
->type ()->length ());
1209 memset (bufferp
, 0, value
->type ()->length ());
1212 /* Dispose of the new value. This prevents watchpoints from
1213 trying to watch the saved frame pointer. */
1214 release_value (value
);
1217 /* Get the value of the register that belongs to this FRAME. This
1218 function is a wrapper to the call sequence ``frame_register_unwind
1219 (get_next_frame (FRAME))''. As per frame_register_unwind(), if
1220 VALUEP is NULL, the registers value is not fetched/computed. */
1223 frame_register (frame_info_ptr frame
, int regnum
,
1224 int *optimizedp
, int *unavailablep
, enum lval_type
*lvalp
,
1225 CORE_ADDR
*addrp
, int *realnump
, gdb_byte
*bufferp
)
1227 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1228 that the value proper does not need to be fetched. */
1229 gdb_assert (optimizedp
!= NULL
);
1230 gdb_assert (lvalp
!= NULL
);
1231 gdb_assert (addrp
!= NULL
);
1232 gdb_assert (realnump
!= NULL
);
1233 /* gdb_assert (bufferp != NULL); */
1235 /* Obtain the register value by unwinding the register from the next
1236 (more inner frame). */
1237 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
1238 frame_register_unwind (frame_info_ptr (frame
->next
), regnum
, optimizedp
,
1239 unavailablep
, lvalp
, addrp
, realnump
, bufferp
);
1243 frame_unwind_register (frame_info_ptr next_frame
, int regnum
, gdb_byte
*buf
)
1249 enum lval_type lval
;
1251 frame_register_unwind (next_frame
, regnum
, &optimized
, &unavailable
,
1252 &lval
, &addr
, &realnum
, buf
);
1255 throw_error (OPTIMIZED_OUT_ERROR
,
1256 _("Register %d was not saved"), regnum
);
1258 throw_error (NOT_AVAILABLE_ERROR
,
1259 _("Register %d is not available"), regnum
);
1263 get_frame_register (frame_info_ptr frame
,
1264 int regnum
, gdb_byte
*buf
)
1266 frame_unwind_register (frame_info_ptr (frame
->next
), regnum
, buf
);
1270 frame_unwind_register_value (frame_info_ptr next_frame
, int regnum
)
1272 FRAME_SCOPED_DEBUG_ENTER_EXIT
;
1274 gdb_assert (next_frame
!= NULL
);
1275 gdbarch
*gdbarch
= frame_unwind_arch (next_frame
);
1276 frame_debug_printf ("frame=%d, regnum=%d(%s)",
1277 next_frame
->level
, regnum
,
1278 user_reg_map_regnum_to_name (gdbarch
, regnum
));
1280 /* Find the unwinder. */
1281 if (next_frame
->unwind
== NULL
)
1282 frame_unwind_find_by_frame (next_frame
, &next_frame
->prologue_cache
);
1284 /* Ask this frame to unwind its register. */
1285 value
*value
= next_frame
->unwind
->prev_register (next_frame
,
1286 &next_frame
->prologue_cache
,
1291 string_file debug_file
;
1293 gdb_printf (&debug_file
, " ->");
1294 if (value
->optimized_out ())
1296 gdb_printf (&debug_file
, " ");
1297 val_print_not_saved (&debug_file
);
1301 if (value
->lval () == lval_register
)
1302 gdb_printf (&debug_file
, " register=%d",
1303 VALUE_REGNUM (value
));
1304 else if (value
->lval () == lval_memory
)
1305 gdb_printf (&debug_file
, " address=%s",
1307 value
->address ()));
1309 gdb_printf (&debug_file
, " computed");
1312 gdb_printf (&debug_file
, " lazy");
1316 gdb::array_view
<const gdb_byte
> buf
= value
->contents ();
1318 gdb_printf (&debug_file
, " bytes=");
1319 gdb_printf (&debug_file
, "[");
1320 for (i
= 0; i
< register_size (gdbarch
, regnum
); i
++)
1321 gdb_printf (&debug_file
, "%02x", buf
[i
]);
1322 gdb_printf (&debug_file
, "]");
1326 frame_debug_printf ("%s", debug_file
.c_str ());
1333 get_frame_register_value (frame_info_ptr frame
, int regnum
)
1335 return frame_unwind_register_value (frame_info_ptr (frame
->next
), regnum
);
1339 frame_unwind_register_signed (frame_info_ptr next_frame
, int regnum
)
1341 struct gdbarch
*gdbarch
= frame_unwind_arch (next_frame
);
1342 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1343 struct value
*value
= frame_unwind_register_value (next_frame
, regnum
);
1345 gdb_assert (value
!= NULL
);
1347 if (value
->optimized_out ())
1349 throw_error (OPTIMIZED_OUT_ERROR
,
1350 _("Register %d was not saved"), regnum
);
1352 if (!value
->entirely_available ())
1354 throw_error (NOT_AVAILABLE_ERROR
,
1355 _("Register %d is not available"), regnum
);
1358 LONGEST r
= extract_signed_integer (value
->contents_all (), byte_order
);
1360 release_value (value
);
1365 get_frame_register_signed (frame_info_ptr frame
, int regnum
)
1367 return frame_unwind_register_signed (frame_info_ptr (frame
->next
), regnum
);
1371 frame_unwind_register_unsigned (frame_info_ptr next_frame
, int regnum
)
1373 struct gdbarch
*gdbarch
= frame_unwind_arch (next_frame
);
1374 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1375 int size
= register_size (gdbarch
, regnum
);
1376 struct value
*value
= frame_unwind_register_value (next_frame
, regnum
);
1378 gdb_assert (value
!= NULL
);
1380 if (value
->optimized_out ())
1382 throw_error (OPTIMIZED_OUT_ERROR
,
1383 _("Register %d was not saved"), regnum
);
1385 if (!value
->entirely_available ())
1387 throw_error (NOT_AVAILABLE_ERROR
,
1388 _("Register %d is not available"), regnum
);
1391 ULONGEST r
= extract_unsigned_integer (value
->contents_all ().data (),
1394 release_value (value
);
1399 get_frame_register_unsigned (frame_info_ptr frame
, int regnum
)
1401 return frame_unwind_register_unsigned (frame_info_ptr (frame
->next
), regnum
);
1405 read_frame_register_unsigned (frame_info_ptr frame
, int regnum
,
1408 struct value
*regval
= get_frame_register_value (frame
, regnum
);
1410 if (!regval
->optimized_out ()
1411 && regval
->entirely_available ())
1413 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1414 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
1415 int size
= register_size (gdbarch
, VALUE_REGNUM (regval
));
1417 *val
= extract_unsigned_integer (regval
->contents ().data (), size
,
1426 put_frame_register (frame_info_ptr frame
, int regnum
,
1427 const gdb_byte
*buf
)
1429 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1433 enum lval_type lval
;
1436 frame_register (frame
, regnum
, &optim
, &unavail
,
1437 &lval
, &addr
, &realnum
, NULL
);
1439 error (_("Attempt to assign to a register that was not saved."));
1444 write_memory (addr
, buf
, register_size (gdbarch
, regnum
));
1448 get_thread_regcache (inferior_thread ())->cooked_write (realnum
, buf
);
1451 error (_("Attempt to assign to an unmodifiable value."));
1455 /* This function is deprecated. Use get_frame_register_value instead,
1456 which provides more accurate information.
1458 Find and return the value of REGNUM for the specified stack frame.
1459 The number of bytes copied is REGISTER_SIZE (REGNUM).
1461 Returns 0 if the register value could not be found. */
1464 deprecated_frame_register_read (frame_info_ptr frame
, int regnum
,
1469 enum lval_type lval
;
1473 frame_register (frame
, regnum
, &optimized
, &unavailable
,
1474 &lval
, &addr
, &realnum
, myaddr
);
1476 return !optimized
&& !unavailable
;
1480 get_frame_register_bytes (frame_info_ptr frame
, int regnum
,
1482 gdb::array_view
<gdb_byte
> buffer
,
1483 int *optimizedp
, int *unavailablep
)
1485 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1490 /* Skip registers wholly inside of OFFSET. */
1491 while (offset
>= register_size (gdbarch
, regnum
))
1493 offset
-= register_size (gdbarch
, regnum
);
1497 /* Ensure that we will not read beyond the end of the register file.
1498 This can only ever happen if the debug information is bad. */
1500 numregs
= gdbarch_num_cooked_regs (gdbarch
);
1501 for (i
= regnum
; i
< numregs
; i
++)
1503 int thissize
= register_size (gdbarch
, i
);
1506 break; /* This register is not available on this architecture. */
1507 maxsize
+= thissize
;
1510 int len
= buffer
.size ();
1512 error (_("Bad debug information detected: "
1513 "Attempt to read %d bytes from registers."), len
);
1515 /* Copy the data. */
1518 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
1523 gdb_byte
*myaddr
= buffer
.data ();
1525 if (curr_len
== register_size (gdbarch
, regnum
))
1527 enum lval_type lval
;
1531 frame_register (frame
, regnum
, optimizedp
, unavailablep
,
1532 &lval
, &addr
, &realnum
, myaddr
);
1533 if (*optimizedp
|| *unavailablep
)
1539 = frame_unwind_register_value (frame_info_ptr (frame
->next
),
1541 gdb_assert (value
!= NULL
);
1542 *optimizedp
= value
->optimized_out ();
1543 *unavailablep
= !value
->entirely_available ();
1545 if (*optimizedp
|| *unavailablep
)
1547 release_value (value
);
1551 memcpy (myaddr
, value
->contents_all ().data () + offset
,
1553 release_value (value
);
1569 put_frame_register_bytes (frame_info_ptr frame
, int regnum
,
1571 gdb::array_view
<const gdb_byte
> buffer
)
1573 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
1575 /* Skip registers wholly inside of OFFSET. */
1576 while (offset
>= register_size (gdbarch
, regnum
))
1578 offset
-= register_size (gdbarch
, regnum
);
1582 int len
= buffer
.size ();
1583 /* Copy the data. */
1586 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
1591 const gdb_byte
*myaddr
= buffer
.data ();
1592 if (curr_len
== register_size (gdbarch
, regnum
))
1594 put_frame_register (frame
, regnum
, myaddr
);
1599 = frame_unwind_register_value (frame_info_ptr (frame
->next
),
1601 gdb_assert (value
!= NULL
);
1603 memcpy ((char *) value
->contents_writeable ().data () + offset
,
1605 put_frame_register (frame
, regnum
,
1606 value
->contents_raw ().data ());
1607 release_value (value
);
1617 /* Create a sentinel frame.
1619 See frame_id_build_sentinel for the description of STACK_ADDR and
1622 static frame_info_ptr
1623 create_sentinel_frame (program_space
*pspace
, address_space
*aspace
,
1624 regcache
*regcache
, CORE_ADDR stack_addr
,
1625 CORE_ADDR code_addr
)
1627 frame_info
*frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1630 frame
->pspace
= pspace
;
1631 frame
->aspace
= aspace
;
1632 /* Explicitly initialize the sentinel frame's cache. Provide it
1633 with the underlying regcache. In the future additional
1634 information, such as the frame's thread will be added. */
1635 frame
->prologue_cache
= sentinel_frame_cache (regcache
);
1636 /* For the moment there is only one sentinel frame implementation. */
1637 frame
->unwind
= &sentinel_frame_unwind
;
1638 /* Link this frame back to itself. The frame is self referential
1639 (the unwound PC is the same as the pc), so make it so. */
1640 frame
->next
= frame
;
1641 /* The sentinel frame has a special ID. */
1642 frame
->this_id
.p
= frame_id_status::COMPUTED
;
1643 frame
->this_id
.value
= frame_id_build_sentinel (stack_addr
, code_addr
);
1645 bool added
= frame_stash_add (frame
);
1648 frame_debug_printf (" -> %s", frame
->to_string ().c_str ());
1650 return frame_info_ptr (frame
);
1653 /* Cache for frame addresses already read by gdb. Valid only while
1654 inferior is stopped. Control variables for the frame cache should
1655 be local to this module. */
1657 static struct obstack frame_cache_obstack
;
1660 frame_obstack_zalloc (unsigned long size
)
1662 void *data
= obstack_alloc (&frame_cache_obstack
, size
);
1664 memset (data
, 0, size
);
1668 static frame_info_ptr
get_prev_frame_always_1 (frame_info_ptr this_frame
);
1671 get_current_frame (void)
1673 frame_info_ptr current_frame
;
1675 /* First check, and report, the lack of registers. Having GDB
1676 report "No stack!" or "No memory" when the target doesn't even
1677 have registers is very confusing. Besides, "printcmd.exp"
1678 explicitly checks that ``print $pc'' with no registers prints "No
1680 if (!target_has_registers ())
1681 error (_("No registers."));
1682 if (!target_has_stack ())
1683 error (_("No stack."));
1684 if (!target_has_memory ())
1685 error (_("No memory."));
1686 /* Traceframes are effectively a substitute for the live inferior. */
1687 if (get_traceframe_number () < 0)
1688 validate_registers_access ();
1690 if (sentinel_frame
== NULL
)
1692 create_sentinel_frame (current_program_space
, current_inferior ()->aspace
,
1693 get_thread_regcache (inferior_thread ()),
1696 /* Set the current frame before computing the frame id, to avoid
1697 recursion inside compute_frame_id, in case the frame's
1698 unwinder decides to do a symbol lookup (which depends on the
1699 selected frame's block).
1701 This call must always succeed. In particular, nothing inside
1702 get_prev_frame_always_1 should try to unwind from the
1703 sentinel frame, because that could fail/throw, and we always
1704 want to leave with the current frame created and linked in --
1705 we should never end up with the sentinel frame as outermost
1707 current_frame
= get_prev_frame_always_1 (frame_info_ptr (sentinel_frame
));
1708 gdb_assert (current_frame
!= NULL
);
1710 return current_frame
;
1713 /* The "selected" stack frame is used by default for local and arg
1716 The "single source of truth" for the selected frame is the
1717 SELECTED_FRAME_ID / SELECTED_FRAME_LEVEL pair.
1719 Frame IDs can be saved/restored across reinitializing the frame
1720 cache, while frame_info pointers can't (frame_info objects are
1721 invalidated). If we know the corresponding frame_info object, it
1722 is cached in SELECTED_FRAME.
1724 If SELECTED_FRAME_ID / SELECTED_FRAME_LEVEL are null_frame_id / -1,
1725 and the target has stack and is stopped, the selected frame is the
1726 current (innermost) target frame. SELECTED_FRAME_ID is never the ID
1727 of the current (innermost) target frame. SELECTED_FRAME_LEVEL may
1728 only be 0 if the selected frame is a user-created one (created and
1729 selected through the "select-frame view" command), in which case
1730 SELECTED_FRAME_ID is the frame id derived from the user-provided
1733 If SELECTED_FRAME_ID / SELECTED_FRAME_LEVEL are null_frame_id / -1,
1734 and the target has no stack or is executing, then there's no
1736 static frame_id selected_frame_id
= null_frame_id
;
1737 static int selected_frame_level
= -1;
1739 /* See frame.h. This definition should come before any definition of a static
1740 frame_info_ptr, to ensure that frame_list is destroyed after any static
1741 frame_info_ptr. This is necessary because the destructor of frame_info_ptr
1744 intrusive_list
<frame_info_ptr
> frame_info_ptr::frame_list
;
1746 /* The cached frame_info object pointing to the selected frame.
1747 Looked up on demand by get_selected_frame. */
1748 static frame_info_ptr selected_frame
;
1753 save_selected_frame (frame_id
*frame_id
, int *frame_level
)
1756 *frame_id
= selected_frame_id
;
1757 *frame_level
= selected_frame_level
;
1763 restore_selected_frame (frame_id frame_id
, int frame_level
)
1766 /* Unless it is a user-created frame, save_selected_frame never returns
1767 level == 0, so we shouldn't see it here either. */
1768 gdb_assert (frame_level
!= 0 || frame_id
.user_created_p
);
1770 /* FRAME_ID can be null_frame_id only IFF frame_level is -1. */
1771 gdb_assert ((frame_level
== -1 && !frame_id_p (frame_id
))
1772 || (frame_level
!= -1 && frame_id_p (frame_id
)));
1774 selected_frame_id
= frame_id
;
1775 selected_frame_level
= frame_level
;
1777 /* Will be looked up later by get_selected_frame. */
1778 selected_frame
= nullptr;
1781 /* Lookup the frame_info object for the selected frame FRAME_ID /
1782 FRAME_LEVEL and cache the result.
1784 If FRAME_LEVEL > 0 and the originally selected frame isn't found,
1785 warn and select the innermost (current) frame. */
1788 lookup_selected_frame (struct frame_id a_frame_id
, int frame_level
)
1790 frame_info_ptr frame
= NULL
;
1793 /* This either means there was no selected frame, or the selected
1794 frame was the current frame. In either case, select the current
1796 if (frame_level
== -1)
1798 select_frame (get_current_frame ());
1802 /* This means the selected frame was a user-created one. Create a new one
1803 using the user-provided addresses, which happen to be in the frame id. */
1804 if (frame_level
== 0)
1806 gdb_assert (a_frame_id
.user_created_p
);
1807 select_frame (create_new_frame (a_frame_id
));
1811 /* select_frame never saves 0 in SELECTED_FRAME_LEVEL, so we
1812 shouldn't see it here. */
1813 gdb_assert (frame_level
> 0);
1815 /* Restore by level first, check if the frame id is the same as
1816 expected. If that fails, try restoring by frame id. If that
1817 fails, nothing to do, just warn the user. */
1819 count
= frame_level
;
1820 frame
= find_relative_frame (get_current_frame (), &count
);
1823 /* The frame ids must match - either both valid or both
1824 outer_frame_id. The latter case is not failsafe, but since
1825 it's highly unlikely the search by level finds the wrong
1826 frame, it's 99.9(9)% of the time (for all practical purposes)
1828 && get_frame_id (frame
) == a_frame_id
)
1830 /* Cool, all is fine. */
1831 select_frame (frame
);
1835 frame
= frame_find_by_id (a_frame_id
);
1838 /* Cool, refound it. */
1839 select_frame (frame
);
1843 /* Nothing else to do, the frame layout really changed. Select the
1844 innermost stack frame. */
1845 select_frame (get_current_frame ());
1847 /* Warn the user. */
1848 if (frame_level
> 0 && !current_uiout
->is_mi_like_p ())
1850 warning (_("Couldn't restore frame #%d in "
1851 "current thread. Bottom (innermost) frame selected:"),
1853 /* For MI, we should probably have a notification about current
1854 frame change. But this error is not very likely, so don't
1856 print_stack_frame (get_selected_frame (NULL
), 1, SRC_AND_LOC
, 1);
1863 if (!target_has_registers () || !target_has_stack ()
1864 || !target_has_memory ())
1867 /* Traceframes are effectively a substitute for the live inferior. */
1868 if (get_traceframe_number () < 0)
1870 /* No current inferior, no frame. */
1871 if (inferior_ptid
== null_ptid
)
1874 thread_info
*tp
= inferior_thread ();
1875 /* Don't try to read from a dead thread. */
1876 if (tp
->state
== THREAD_EXITED
)
1879 /* ... or from a spinning thread. */
1880 if (tp
->executing ())
1890 get_selected_frame (const char *message
)
1892 if (selected_frame
== NULL
)
1894 if (message
!= NULL
&& !has_stack_frames ())
1895 error (("%s"), message
);
1897 lookup_selected_frame (selected_frame_id
, selected_frame_level
);
1899 /* There is always a frame. */
1900 gdb_assert (selected_frame
!= NULL
);
1901 return selected_frame
;
1904 /* This is a variant of get_selected_frame() which can be called when
1905 the inferior does not have a frame; in that case it will return
1906 NULL instead of calling error(). */
1909 deprecated_safe_get_selected_frame (void)
1911 if (!has_stack_frames ())
1913 return get_selected_frame (NULL
);
1916 /* Invalidate the selected frame. */
1919 invalidate_selected_frame ()
1921 selected_frame
= nullptr;
1922 selected_frame_level
= -1;
1923 selected_frame_id
= null_frame_id
;
1929 select_frame (frame_info_ptr fi
)
1931 gdb_assert (fi
!= nullptr);
1933 selected_frame
= fi
;
1934 selected_frame_level
= frame_relative_level (fi
);
1936 /* If the frame is a user-created one, save its level and frame id just like
1937 any other non-level-0 frame. */
1938 if (selected_frame_level
== 0 && !fi
->this_id
.value
.user_created_p
)
1940 /* Treat the current frame especially -- we want to always
1941 save/restore it without warning, even if the frame ID changes
1942 (see lookup_selected_frame). E.g.:
1944 // The current frame is selected, the target had just stopped.
1946 scoped_restore_selected_frame restore_frame;
1947 some_operation_that_changes_the_stack ();
1949 // scoped_restore_selected_frame's dtor runs, but the
1950 // original frame_id can't be found. No matter whether it
1951 // is found or not, we still end up with the now-current
1952 // frame selected. Warning in lookup_selected_frame in this
1953 // case seems pointless.
1955 Also get_frame_id may access the target's registers/memory,
1956 and thus skipping get_frame_id optimizes the common case.
1958 Saving the selected frame this way makes get_selected_frame
1959 and restore_current_frame return/re-select whatever frame is
1960 the innermost (current) then. */
1961 selected_frame_level
= -1;
1962 selected_frame_id
= null_frame_id
;
1965 selected_frame_id
= get_frame_id (fi
);
1967 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
1968 frame is being invalidated. */
1970 /* FIXME: kseitz/2002-08-28: It would be nice to call
1971 selected_frame_level_changed_event() right here, but due to limitations
1972 in the current interfaces, we would end up flooding UIs with events
1973 because select_frame() is used extensively internally.
1975 Once we have frame-parameterized frame (and frame-related) commands,
1976 the event notification can be moved here, since this function will only
1977 be called when the user's selected frame is being changed. */
1979 /* Ensure that symbols for this frame are read in. Also, determine the
1980 source language of this frame, and switch to it if desired. */
1985 /* We retrieve the frame's symtab by using the frame PC.
1986 However we cannot use the frame PC as-is, because it usually
1987 points to the instruction following the "call", which is
1988 sometimes the first instruction of another function. So we
1989 rely on get_frame_address_in_block() which provides us with a
1990 PC which is guaranteed to be inside the frame's code
1992 if (get_frame_address_in_block_if_available (fi
, &pc
))
1994 struct compunit_symtab
*cust
= find_pc_compunit_symtab (pc
);
1997 && cust
->language () != current_language
->la_language
1998 && cust
->language () != language_unknown
1999 && language_mode
== language_mode_auto
)
2000 set_language (cust
->language ());
2005 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
2006 Always returns a non-NULL value. */
2008 static frame_info_ptr
2009 create_new_frame (frame_id id
)
2011 gdb_assert (id
.user_created_p
);
2012 gdb_assert (id
.stack_status
== frame_id_stack_status::FID_STACK_VALID
);
2013 gdb_assert (id
.code_addr_p
);
2015 frame_debug_printf ("stack_addr=%s, core_addr=%s",
2016 hex_string (id
.stack_addr
), hex_string (id
.code_addr
));
2018 /* Avoid creating duplicate frames, search for an existing frame with that id
2020 frame_info_ptr frame
= frame_stash_find (id
);
2021 if (frame
!= nullptr)
2024 frame_info
*fi
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
2026 fi
->next
= create_sentinel_frame (current_program_space
,
2027 current_inferior ()->aspace
,
2028 get_thread_regcache (inferior_thread ()),
2029 id
.stack_addr
, id
.code_addr
).get ();
2031 /* Set/update this frame's cached PC value, found in the next frame.
2032 Do this before looking for this frame's unwinder. A sniffer is
2033 very likely to read this, and the corresponding unwinder is
2034 entitled to rely that the PC doesn't magically change. */
2035 fi
->next
->prev_pc
.value
= id
.code_addr
;
2036 fi
->next
->prev_pc
.status
= CC_VALUE
;
2038 /* We currently assume that frame chain's can't cross spaces. */
2039 fi
->pspace
= fi
->next
->pspace
;
2040 fi
->aspace
= fi
->next
->aspace
;
2042 /* Select/initialize both the unwind function and the frame's type
2044 frame_unwind_find_by_frame (frame_info_ptr (fi
), &fi
->prologue_cache
);
2046 fi
->this_id
.p
= frame_id_status::COMPUTED
;
2047 fi
->this_id
.value
= id
;
2049 bool added
= frame_stash_add (fi
);
2052 frame_debug_printf (" -> %s", fi
->to_string ().c_str ());
2054 return frame_info_ptr (fi
);
2058 create_new_frame (CORE_ADDR stack
, CORE_ADDR pc
)
2060 frame_id id
= frame_id_build (stack
, pc
);
2061 id
.user_created_p
= 1;
2063 return create_new_frame (id
);
2066 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
2067 innermost frame). Be careful to not fall off the bottom of the
2068 frame chain and onto the sentinel frame. */
2071 get_next_frame (frame_info_ptr this_frame
)
2073 if (this_frame
->level
> 0)
2074 return frame_info_ptr (this_frame
->next
);
2079 /* Return the frame that THIS_FRAME calls. If THIS_FRAME is the
2080 innermost (i.e. current) frame, return the sentinel frame. Thus,
2081 unlike get_next_frame(), NULL will never be returned. */
2084 get_next_frame_sentinel_okay (frame_info_ptr this_frame
)
2086 gdb_assert (this_frame
!= NULL
);
2088 /* Note that, due to the manner in which the sentinel frame is
2089 constructed, this_frame->next still works even when this_frame
2090 is the sentinel frame. But we disallow it here anyway because
2091 calling get_next_frame_sentinel_okay() on the sentinel frame
2092 is likely a coding error. */
2093 if (this_frame
->this_id
.p
== frame_id_status::COMPUTED
)
2094 gdb_assert (!is_sentinel_frame_id (this_frame
->this_id
.value
));
2096 return frame_info_ptr (this_frame
->next
);
2099 /* Observer for the target_changed event. */
2102 frame_observer_target_changed (struct target_ops
*target
)
2104 reinit_frame_cache ();
2107 /* Flush the entire frame cache. */
2110 reinit_frame_cache (void)
2112 ++frame_cache_generation
;
2114 if (htab_elements (frame_stash
) > 0)
2115 annotate_frames_invalid ();
2117 invalidate_selected_frame ();
2119 /* Invalidate cache. */
2120 if (sentinel_frame
!= nullptr)
2122 /* If frame 0's id is not computed, it is not in the frame stash, so its
2123 dealloc functions will not be called when emptying the frame stash.
2124 Call frame_info_del manually in that case. */
2125 frame_info
*current_frame
= sentinel_frame
->prev
;
2126 if (current_frame
!= nullptr
2127 && current_frame
->this_id
.p
== frame_id_status::NOT_COMPUTED
)
2128 frame_info_del (current_frame
);
2130 sentinel_frame
= nullptr;
2133 frame_stash_invalidate ();
2135 /* Since we can't really be sure what the first object allocated was. */
2136 obstack_free (&frame_cache_obstack
, 0);
2137 obstack_init (&frame_cache_obstack
);
2139 for (frame_info_ptr
&iter
: frame_info_ptr::frame_list
)
2142 frame_debug_printf ("generation=%d", frame_cache_generation
);
2145 /* Find where a register is saved (in memory or another register).
2146 The result of frame_register_unwind is just where it is saved
2147 relative to this particular frame. */
2150 frame_register_unwind_location (frame_info_ptr this_frame
, int regnum
,
2151 int *optimizedp
, enum lval_type
*lvalp
,
2152 CORE_ADDR
*addrp
, int *realnump
)
2154 gdb_assert (this_frame
== NULL
|| this_frame
->level
>= 0);
2156 while (this_frame
!= NULL
)
2160 frame_register_unwind (this_frame
, regnum
, optimizedp
, &unavailable
,
2161 lvalp
, addrp
, realnump
, NULL
);
2166 if (*lvalp
!= lval_register
)
2170 this_frame
= get_next_frame (this_frame
);
2174 /* Get the previous raw frame, and check that it is not identical to
2175 same other frame frame already in the chain. If it is, there is
2176 most likely a stack cycle, so we discard it, and mark THIS_FRAME as
2177 outermost, with UNWIND_SAME_ID stop reason. Unlike the other
2178 validity tests, that compare THIS_FRAME and the next frame, we do
2179 this right after creating the previous frame, to avoid ever ending
2180 up with two frames with the same id in the frame chain.
2182 There is however, one case where this cycle detection is not desirable,
2183 when asking for the previous frame of an inline frame, in this case, if
2184 the previous frame is a duplicate and we return nullptr then we will be
2185 unable to calculate the frame_id of the inline frame, this in turn
2186 causes inline_frame_this_id() to fail. So for inline frames (and only
2187 for inline frames), the previous frame will always be returned, even when it
2188 has a duplicate frame_id. We're not worried about cycles in the frame
2189 chain as, if the previous frame returned here has a duplicate frame_id,
2190 then the frame_id of the inline frame, calculated based off the frame_id
2191 of the previous frame, should also be a duplicate. */
2193 static frame_info_ptr
2194 get_prev_frame_maybe_check_cycle (frame_info_ptr this_frame
)
2196 frame_info_ptr prev_frame
= get_prev_frame_raw (this_frame
);
2198 /* Don't compute the frame id of the current frame yet. Unwinding
2199 the sentinel frame can fail (e.g., if the thread is gone and we
2200 can't thus read its registers). If we let the cycle detection
2201 code below try to compute a frame ID, then an error thrown from
2202 within the frame ID computation would result in the sentinel
2203 frame as outermost frame, which is bogus. Instead, we'll compute
2204 the current frame's ID lazily in get_frame_id. Note that there's
2205 no point in doing cycle detection when there's only one frame, so
2206 nothing is lost here. */
2207 if (prev_frame
->level
== 0)
2210 unsigned int entry_generation
= get_frame_cache_generation ();
2214 compute_frame_id (prev_frame
);
2216 bool cycle_detection_p
= get_frame_type (this_frame
) != INLINE_FRAME
;
2218 /* This assert checks GDB's state with respect to calculating the
2219 frame-id of THIS_FRAME, in the case where THIS_FRAME is an inline
2222 If THIS_FRAME is frame #0, and is an inline frame, then we put off
2223 calculating the frame_id until we specifically make a call to
2224 get_frame_id(). As a result we can enter this function in two
2225 possible states. If GDB asked for the previous frame of frame #0
2226 then THIS_FRAME will be frame #0 (an inline frame), and the
2227 frame_id will be in the NOT_COMPUTED state. However, if GDB asked
2228 for the frame_id of frame #0, then, as getting the frame_id of an
2229 inline frame requires us to get the frame_id of the previous
2230 frame, we will still end up in here, and the frame_id status will
2233 If, instead, THIS_FRAME is at a level greater than #0 then things
2234 are simpler. For these frames we immediately compute the frame_id
2235 when the frame is initially created, and so, for those frames, we
2236 will always enter this function with the frame_id status of
2238 gdb_assert (cycle_detection_p
2239 || (this_frame
->level
> 0
2240 && (this_frame
->this_id
.p
2241 == frame_id_status::COMPUTING
))
2242 || (this_frame
->level
== 0
2243 && (this_frame
->this_id
.p
2244 != frame_id_status::COMPUTED
)));
2246 /* We must do the CYCLE_DETECTION_P check after attempting to add
2247 PREV_FRAME into the cache; if PREV_FRAME is unique then we do want
2248 it in the cache, but if it is a duplicate and CYCLE_DETECTION_P is
2249 false, then we don't want to unlink it. */
2250 if (!frame_stash_add (prev_frame
.get ()) && cycle_detection_p
)
2252 /* Another frame with the same id was already in the stash. We just
2253 detected a cycle. */
2254 frame_debug_printf (" -> nullptr // this frame has same ID");
2256 this_frame
->stop_reason
= UNWIND_SAME_ID
;
2258 prev_frame
->next
= NULL
;
2259 this_frame
->prev
= NULL
;
2263 catch (const gdb_exception
&ex
)
2265 if (get_frame_cache_generation () == entry_generation
)
2267 prev_frame
->next
= NULL
;
2268 this_frame
->prev
= NULL
;
2277 /* Helper function for get_prev_frame_always, this is called inside a
2278 TRY_CATCH block. Return the frame that called THIS_FRAME or NULL if
2279 there is no such frame. This may throw an exception. */
2281 static frame_info_ptr
2282 get_prev_frame_always_1 (frame_info_ptr this_frame
)
2284 FRAME_SCOPED_DEBUG_ENTER_EXIT
;
2286 gdb_assert (this_frame
!= NULL
);
2290 if (this_frame
!= NULL
)
2291 frame_debug_printf ("this_frame=%d", this_frame
->level
);
2293 frame_debug_printf ("this_frame=nullptr");
2296 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
2298 /* Only try to do the unwind once. */
2299 if (this_frame
->prev_p
)
2301 if (this_frame
->prev
!= nullptr)
2302 frame_debug_printf (" -> %s // cached",
2303 this_frame
->prev
->to_string ().c_str ());
2306 (" -> nullptr // %s // cached",
2307 frame_stop_reason_symbol_string (this_frame
->stop_reason
));
2308 return frame_info_ptr (this_frame
->prev
);
2311 /* If the frame unwinder hasn't been selected yet, we must do so
2312 before setting prev_p; otherwise the check for misbehaved
2313 sniffers will think that this frame's sniffer tried to unwind
2314 further (see frame_cleanup_after_sniffer). */
2315 if (this_frame
->unwind
== NULL
)
2316 frame_unwind_find_by_frame (this_frame
, &this_frame
->prologue_cache
);
2318 this_frame
->prev_p
= true;
2319 this_frame
->stop_reason
= UNWIND_NO_REASON
;
2321 /* If we are unwinding from an inline frame, all of the below tests
2322 were already performed when we unwound from the next non-inline
2323 frame. We must skip them, since we can not get THIS_FRAME's ID
2324 until we have unwound all the way down to the previous non-inline
2326 if (get_frame_type (this_frame
) == INLINE_FRAME
)
2327 return get_prev_frame_maybe_check_cycle (this_frame
);
2329 /* If this_frame is the current frame, then compute and stash its
2330 frame id prior to fetching and computing the frame id of the
2331 previous frame. Otherwise, the cycle detection code in
2332 get_prev_frame_if_no_cycle() will not work correctly. When
2333 get_frame_id() is called later on, an assertion error will be
2334 triggered in the event of a cycle between the current frame and
2337 Note we do this after the INLINE_FRAME check above. That is
2338 because the inline frame's frame id computation needs to fetch
2339 the frame id of its previous real stack frame. I.e., we need to
2340 avoid recursion in that case. This is OK since we're sure the
2341 inline frame won't create a cycle with the real stack frame. See
2342 inline_frame_this_id. */
2343 if (this_frame
->level
== 0)
2344 get_frame_id (this_frame
);
2346 /* Check that this frame is unwindable. If it isn't, don't try to
2347 unwind to the prev frame. */
2348 this_frame
->stop_reason
2349 = this_frame
->unwind
->stop_reason (this_frame
,
2350 &this_frame
->prologue_cache
);
2352 if (this_frame
->stop_reason
!= UNWIND_NO_REASON
)
2355 (" -> nullptr // %s",
2356 frame_stop_reason_symbol_string (this_frame
->stop_reason
));
2360 /* Check that this frame's ID isn't inner to (younger, below, next)
2361 the next frame. This happens when a frame unwind goes backwards.
2362 This check is valid only if this frame and the next frame are NORMAL.
2363 See the comment at frame_id_inner for details. */
2364 if (get_frame_type (this_frame
) == NORMAL_FRAME
2365 && this_frame
->next
->unwind
->type
== NORMAL_FRAME
2366 && frame_id_inner (get_frame_arch (frame_info_ptr (this_frame
->next
)),
2367 get_frame_id (this_frame
),
2368 get_frame_id (frame_info_ptr (this_frame
->next
))))
2370 CORE_ADDR this_pc_in_block
;
2371 struct minimal_symbol
*morestack_msym
;
2372 const char *morestack_name
= NULL
;
2374 /* gcc -fsplit-stack __morestack can continue the stack anywhere. */
2375 this_pc_in_block
= get_frame_address_in_block (this_frame
);
2376 morestack_msym
= lookup_minimal_symbol_by_pc (this_pc_in_block
).minsym
;
2378 morestack_name
= morestack_msym
->linkage_name ();
2379 if (!morestack_name
|| strcmp (morestack_name
, "__morestack") != 0)
2381 frame_debug_printf (" -> nullptr // this frame ID is inner");
2382 this_frame
->stop_reason
= UNWIND_INNER_ID
;
2387 /* Check that this and the next frame do not unwind the PC register
2388 to the same memory location. If they do, then even though they
2389 have different frame IDs, the new frame will be bogus; two
2390 functions can't share a register save slot for the PC. This can
2391 happen when the prologue analyzer finds a stack adjustment, but
2394 This check does assume that the "PC register" is roughly a
2395 traditional PC, even if the gdbarch_unwind_pc method adjusts
2396 it (we do not rely on the value, only on the unwound PC being
2397 dependent on this value). A potential improvement would be
2398 to have the frame prev_pc method and the gdbarch unwind_pc
2399 method set the same lval and location information as
2400 frame_register_unwind. */
2401 if (this_frame
->level
> 0
2402 && gdbarch_pc_regnum (gdbarch
) >= 0
2403 && get_frame_type (this_frame
) == NORMAL_FRAME
2404 && (get_frame_type (frame_info_ptr (this_frame
->next
)) == NORMAL_FRAME
2405 || get_frame_type (frame_info_ptr (this_frame
->next
)) == INLINE_FRAME
))
2407 int optimized
, realnum
, nrealnum
;
2408 enum lval_type lval
, nlval
;
2409 CORE_ADDR addr
, naddr
;
2411 frame_register_unwind_location (this_frame
,
2412 gdbarch_pc_regnum (gdbarch
),
2413 &optimized
, &lval
, &addr
, &realnum
);
2414 frame_register_unwind_location (get_next_frame (this_frame
),
2415 gdbarch_pc_regnum (gdbarch
),
2416 &optimized
, &nlval
, &naddr
, &nrealnum
);
2418 if ((lval
== lval_memory
&& lval
== nlval
&& addr
== naddr
)
2419 || (lval
== lval_register
&& lval
== nlval
&& realnum
== nrealnum
))
2421 frame_debug_printf (" -> nullptr // no saved PC");
2422 this_frame
->stop_reason
= UNWIND_NO_SAVED_PC
;
2423 this_frame
->prev
= NULL
;
2428 return get_prev_frame_maybe_check_cycle (this_frame
);
2431 /* Return a "struct frame_info" corresponding to the frame that called
2432 THIS_FRAME. Returns NULL if there is no such frame.
2434 Unlike get_prev_frame, this function always tries to unwind the
2438 get_prev_frame_always (frame_info_ptr this_frame
)
2440 frame_info_ptr prev_frame
= NULL
;
2444 prev_frame
= get_prev_frame_always_1 (this_frame
);
2446 catch (const gdb_exception_error
&ex
)
2448 if (ex
.error
== MEMORY_ERROR
)
2450 this_frame
->stop_reason
= UNWIND_MEMORY_ERROR
;
2451 if (ex
.message
!= NULL
)
2456 /* The error needs to live as long as the frame does.
2457 Allocate using stack local STOP_STRING then assign the
2458 pointer to the frame, this allows the STOP_STRING on the
2459 frame to be of type 'const char *'. */
2460 size
= ex
.message
->size () + 1;
2461 stop_string
= (char *) frame_obstack_zalloc (size
);
2462 memcpy (stop_string
, ex
.what (), size
);
2463 this_frame
->stop_string
= stop_string
;
2474 /* Construct a new "struct frame_info" and link it previous to
2477 static frame_info_ptr
2478 get_prev_frame_raw (frame_info_ptr this_frame
)
2480 frame_info
*prev_frame
;
2482 /* Allocate the new frame but do not wire it in to the frame chain.
2483 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
2484 frame->next to pull some fancy tricks (of course such code is, by
2485 definition, recursive). Try to prevent it.
2487 There is no reason to worry about memory leaks, should the
2488 remainder of the function fail. The allocated memory will be
2489 quickly reclaimed when the frame cache is flushed, and the `we've
2490 been here before' check above will stop repeated memory
2491 allocation calls. */
2492 prev_frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
2493 prev_frame
->level
= this_frame
->level
+ 1;
2495 /* For now, assume we don't have frame chains crossing address
2497 prev_frame
->pspace
= this_frame
->pspace
;
2498 prev_frame
->aspace
= this_frame
->aspace
;
2500 /* Don't yet compute ->unwind (and hence ->type). It is computed
2501 on-demand in get_frame_type, frame_register_unwind, and
2504 /* Don't yet compute the frame's ID. It is computed on-demand by
2507 /* The unwound frame ID is validate at the start of this function,
2508 as part of the logic to decide if that frame should be further
2509 unwound, and not here while the prev frame is being created.
2510 Doing this makes it possible for the user to examine a frame that
2511 has an invalid frame ID.
2513 Some very old VAX code noted: [...] For the sake of argument,
2514 suppose that the stack is somewhat trashed (which is one reason
2515 that "info frame" exists). So, return 0 (indicating we don't
2516 know the address of the arglist) if we don't know what frame this
2520 this_frame
->prev
= prev_frame
;
2521 prev_frame
->next
= this_frame
.get ();
2523 frame_debug_printf (" -> %s", prev_frame
->to_string ().c_str ());
2525 return frame_info_ptr (prev_frame
);
2528 /* Debug routine to print a NULL frame being returned. */
2531 frame_debug_got_null_frame (frame_info_ptr this_frame
,
2536 if (this_frame
!= NULL
)
2537 frame_debug_printf ("this_frame=%d -> %s", this_frame
->level
, reason
);
2539 frame_debug_printf ("this_frame=nullptr -> %s", reason
);
2543 /* Is this (non-sentinel) frame in the "main"() function? */
2546 inside_main_func (frame_info_ptr this_frame
)
2548 if (current_program_space
->symfile_object_file
== nullptr)
2551 CORE_ADDR sym_addr
= 0;
2552 const char *name
= main_name ();
2553 bound_minimal_symbol msymbol
2554 = lookup_minimal_symbol (name
, NULL
,
2555 current_program_space
->symfile_object_file
);
2557 if (msymbol
.minsym
!= nullptr)
2558 sym_addr
= msymbol
.value_address ();
2560 /* Favor a full symbol in Fortran, for the case where the Fortran main
2561 is also called "main". */
2562 if (msymbol
.minsym
== nullptr
2563 || get_frame_language (this_frame
) == language_fortran
)
2565 /* In some language (for example Fortran) there will be no minimal
2566 symbol with the name of the main function. In this case we should
2567 search the full symbols to see if we can find a match. */
2568 struct block_symbol bs
= lookup_symbol (name
, NULL
, VAR_DOMAIN
, 0);
2570 /* We might have found some unrelated symbol. For example, the
2571 Rust compiler can emit both a subprogram and a namespace with
2572 the same name in the same scope; and due to how gdb's symbol
2573 tables currently work, we can't request the one we'd
2575 if (bs
.symbol
!= nullptr && bs
.symbol
->aclass () == LOC_BLOCK
)
2577 const struct block
*block
= bs
.symbol
->value_block ();
2578 gdb_assert (block
!= nullptr);
2579 sym_addr
= block
->start ();
2581 else if (msymbol
.minsym
== nullptr)
2585 /* Convert any function descriptor addresses into the actual function
2587 sym_addr
= (gdbarch_convert_from_func_ptr_addr
2588 (get_frame_arch (this_frame
), sym_addr
,
2589 current_inferior ()->top_target ()));
2591 return sym_addr
== get_frame_func (this_frame
);
2594 /* Test whether THIS_FRAME is inside the process entry point function. */
2597 inside_entry_func (frame_info_ptr this_frame
)
2599 CORE_ADDR entry_point
;
2601 if (!entry_point_address_query (&entry_point
))
2604 return get_frame_func (this_frame
) == entry_point
;
2607 /* Return a structure containing various interesting information about
2608 the frame that called THIS_FRAME. Returns NULL if there is either
2609 no such frame or the frame fails any of a set of target-independent
2610 condition that should terminate the frame chain (e.g., as unwinding
2613 This function should not contain target-dependent tests, such as
2614 checking whether the program-counter is zero. */
2617 get_prev_frame (frame_info_ptr this_frame
)
2619 FRAME_SCOPED_DEBUG_ENTER_EXIT
;
2624 /* There is always a frame. If this assertion fails, suspect that
2625 something should be calling get_selected_frame() or
2626 get_current_frame(). */
2627 gdb_assert (this_frame
!= NULL
);
2629 frame_pc_p
= get_frame_pc_if_available (this_frame
, &frame_pc
);
2631 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
2632 sense to stop unwinding at a dummy frame. One place where a dummy
2633 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
2634 pcsqh register (space register for the instruction at the head of the
2635 instruction queue) cannot be written directly; the only way to set it
2636 is to branch to code that is in the target space. In order to implement
2637 frame dummies on HPUX, the called function is made to jump back to where
2638 the inferior was when the user function was called. If gdb was inside
2639 the main function when we created the dummy frame, the dummy frame will
2640 point inside the main function. */
2641 if (this_frame
->level
>= 0
2642 && get_frame_type (this_frame
) == NORMAL_FRAME
2643 && !user_set_backtrace_options
.backtrace_past_main
2645 && inside_main_func (this_frame
))
2646 /* Don't unwind past main(). Note, this is done _before_ the
2647 frame has been marked as previously unwound. That way if the
2648 user later decides to enable unwinds past main(), that will
2649 automatically happen. */
2651 frame_debug_got_null_frame (this_frame
, "inside main func");
2655 /* If the user's backtrace limit has been exceeded, stop. We must
2656 add two to the current level; one of those accounts for backtrace_limit
2657 being 1-based and the level being 0-based, and the other accounts for
2658 the level of the new frame instead of the level of the current
2660 if (this_frame
->level
+ 2 > user_set_backtrace_options
.backtrace_limit
)
2662 frame_debug_got_null_frame (this_frame
, "backtrace limit exceeded");
2666 /* If we're already inside the entry function for the main objfile,
2667 then it isn't valid. Don't apply this test to a dummy frame -
2668 dummy frame PCs typically land in the entry func. Don't apply
2669 this test to the sentinel frame. Sentinel frames should always
2670 be allowed to unwind. */
2671 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
2672 wasn't checking for "main" in the minimal symbols. With that
2673 fixed asm-source tests now stop in "main" instead of halting the
2674 backtrace in weird and wonderful ways somewhere inside the entry
2675 file. Suspect that tests for inside the entry file/func were
2676 added to work around that (now fixed) case. */
2677 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
2678 suggested having the inside_entry_func test use the
2679 inside_main_func() msymbol trick (along with entry_point_address()
2680 I guess) to determine the address range of the start function.
2681 That should provide a far better stopper than the current
2683 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
2684 applied tail-call optimizations to main so that a function called
2685 from main returns directly to the caller of main. Since we don't
2686 stop at main, we should at least stop at the entry point of the
2688 if (this_frame
->level
>= 0
2689 && get_frame_type (this_frame
) == NORMAL_FRAME
2690 && !user_set_backtrace_options
.backtrace_past_entry
2692 && inside_entry_func (this_frame
))
2694 frame_debug_got_null_frame (this_frame
, "inside entry func");
2698 /* Assume that the only way to get a zero PC is through something
2699 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
2700 will never unwind a zero PC. */
2701 if (this_frame
->level
> 0
2702 && (get_frame_type (this_frame
) == NORMAL_FRAME
2703 || get_frame_type (this_frame
) == INLINE_FRAME
)
2704 && get_frame_type (get_next_frame (this_frame
)) == NORMAL_FRAME
2705 && frame_pc_p
&& frame_pc
== 0)
2707 frame_debug_got_null_frame (this_frame
, "zero PC");
2711 return get_prev_frame_always (this_frame
);
2715 get_frame_pc (frame_info_ptr frame
)
2717 gdb_assert (frame
->next
!= NULL
);
2718 return frame_unwind_pc (frame_info_ptr (frame
->next
));
2722 get_frame_pc_if_available (frame_info_ptr frame
, CORE_ADDR
*pc
)
2725 gdb_assert (frame
->next
!= NULL
);
2729 *pc
= frame_unwind_pc (frame_info_ptr (frame
->next
));
2731 catch (const gdb_exception_error
&ex
)
2733 if (ex
.error
== NOT_AVAILABLE_ERROR
)
2742 /* Return an address that falls within THIS_FRAME's code block. */
2745 get_frame_address_in_block (frame_info_ptr this_frame
)
2747 /* A draft address. */
2748 CORE_ADDR pc
= get_frame_pc (this_frame
);
2750 frame_info_ptr
next_frame (this_frame
->next
);
2752 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
2753 Normally the resume address is inside the body of the function
2754 associated with THIS_FRAME, but there is a special case: when
2755 calling a function which the compiler knows will never return
2756 (for instance abort), the call may be the very last instruction
2757 in the calling function. The resume address will point after the
2758 call and may be at the beginning of a different function
2761 If THIS_FRAME is a signal frame or dummy frame, then we should
2762 not adjust the unwound PC. For a dummy frame, GDB pushed the
2763 resume address manually onto the stack. For a signal frame, the
2764 OS may have pushed the resume address manually and invoked the
2765 handler (e.g. GNU/Linux), or invoked the trampoline which called
2766 the signal handler - but in either case the signal handler is
2767 expected to return to the trampoline. So in both of these
2768 cases we know that the resume address is executable and
2769 related. So we only need to adjust the PC if THIS_FRAME
2770 is a normal function.
2772 If the program has been interrupted while THIS_FRAME is current,
2773 then clearly the resume address is inside the associated
2774 function. There are three kinds of interruption: debugger stop
2775 (next frame will be SENTINEL_FRAME), operating system
2776 signal or exception (next frame will be SIGTRAMP_FRAME),
2777 or debugger-induced function call (next frame will be
2778 DUMMY_FRAME). So we only need to adjust the PC if
2779 NEXT_FRAME is a normal function.
2781 We check the type of NEXT_FRAME first, since it is already
2782 known; frame type is determined by the unwinder, and since
2783 we have THIS_FRAME we've already selected an unwinder for
2786 If the next frame is inlined, we need to keep going until we find
2787 the real function - for instance, if a signal handler is invoked
2788 while in an inlined function, then the code address of the
2789 "calling" normal function should not be adjusted either. */
2791 while (get_frame_type (next_frame
) == INLINE_FRAME
)
2792 next_frame
= frame_info_ptr (next_frame
->next
);
2794 if ((get_frame_type (next_frame
) == NORMAL_FRAME
2795 || get_frame_type (next_frame
) == TAILCALL_FRAME
)
2796 && (get_frame_type (this_frame
) == NORMAL_FRAME
2797 || get_frame_type (this_frame
) == TAILCALL_FRAME
2798 || get_frame_type (this_frame
) == INLINE_FRAME
))
2805 get_frame_address_in_block_if_available (frame_info_ptr this_frame
,
2811 *pc
= get_frame_address_in_block (this_frame
);
2813 catch (const gdb_exception_error
&ex
)
2815 if (ex
.error
== NOT_AVAILABLE_ERROR
)
2824 find_frame_sal (frame_info_ptr frame
)
2826 frame_info_ptr next_frame
;
2830 if (frame_inlined_callees (frame
) > 0)
2834 /* If the current frame has some inlined callees, and we have a next
2835 frame, then that frame must be an inlined frame. In this case
2836 this frame's sal is the "call site" of the next frame's inlined
2837 function, which can not be inferred from get_frame_pc. */
2838 next_frame
= get_next_frame (frame
);
2840 sym
= get_frame_function (next_frame
);
2842 sym
= inline_skipped_symbol (inferior_thread ());
2844 /* If frame is inline, it certainly has symbols. */
2847 symtab_and_line sal
;
2848 if (sym
->line () != 0)
2850 sal
.symtab
= sym
->symtab ();
2851 sal
.line
= sym
->line ();
2854 /* If the symbol does not have a location, we don't know where
2855 the call site is. Do not pretend to. This is jarring, but
2856 we can't do much better. */
2857 sal
.pc
= get_frame_pc (frame
);
2859 sal
.pspace
= get_frame_program_space (frame
);
2863 /* If FRAME is not the innermost frame, that normally means that
2864 FRAME->pc points at the return instruction (which is *after* the
2865 call instruction), and we want to get the line containing the
2866 call (because the call is where the user thinks the program is).
2867 However, if the next frame is either a SIGTRAMP_FRAME or a
2868 DUMMY_FRAME, then the next frame will contain a saved interrupt
2869 PC and such a PC indicates the current (rather than next)
2870 instruction/line, consequently, for such cases, want to get the
2871 line containing fi->pc. */
2872 if (!get_frame_pc_if_available (frame
, &pc
))
2875 notcurrent
= (pc
!= get_frame_address_in_block (frame
));
2876 return find_pc_line (pc
, notcurrent
);
2879 /* Per "frame.h", return the ``address'' of the frame. Code should
2880 really be using get_frame_id(). */
2882 get_frame_base (frame_info_ptr fi
)
2884 return get_frame_id (fi
).stack_addr
;
2887 /* High-level offsets into the frame. Used by the debug info. */
2890 get_frame_base_address (frame_info_ptr fi
)
2892 if (get_frame_type (fi
) != NORMAL_FRAME
)
2894 if (fi
->base
== NULL
)
2895 fi
->base
= frame_base_find_by_frame (fi
);
2896 /* Sneaky: If the low-level unwind and high-level base code share a
2897 common unwinder, let them share the prologue cache. */
2898 if (fi
->base
->unwind
== fi
->unwind
)
2899 return fi
->base
->this_base (fi
, &fi
->prologue_cache
);
2900 return fi
->base
->this_base (fi
, &fi
->base_cache
);
2904 get_frame_locals_address (frame_info_ptr fi
)
2906 if (get_frame_type (fi
) != NORMAL_FRAME
)
2908 /* If there isn't a frame address method, find it. */
2909 if (fi
->base
== NULL
)
2910 fi
->base
= frame_base_find_by_frame (fi
);
2911 /* Sneaky: If the low-level unwind and high-level base code share a
2912 common unwinder, let them share the prologue cache. */
2913 if (fi
->base
->unwind
== fi
->unwind
)
2914 return fi
->base
->this_locals (fi
, &fi
->prologue_cache
);
2915 return fi
->base
->this_locals (fi
, &fi
->base_cache
);
2919 get_frame_args_address (frame_info_ptr fi
)
2921 if (get_frame_type (fi
) != NORMAL_FRAME
)
2923 /* If there isn't a frame address method, find it. */
2924 if (fi
->base
== NULL
)
2925 fi
->base
= frame_base_find_by_frame (fi
);
2926 /* Sneaky: If the low-level unwind and high-level base code share a
2927 common unwinder, let them share the prologue cache. */
2928 if (fi
->base
->unwind
== fi
->unwind
)
2929 return fi
->base
->this_args (fi
, &fi
->prologue_cache
);
2930 return fi
->base
->this_args (fi
, &fi
->base_cache
);
2933 /* Return true if the frame unwinder for frame FI is UNWINDER; false
2937 frame_unwinder_is (frame_info_ptr fi
, const frame_unwind
*unwinder
)
2939 if (fi
->unwind
== nullptr)
2940 frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
2942 return fi
->unwind
== unwinder
;
2945 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
2946 or -1 for a NULL frame. */
2949 frame_relative_level (frame_info_ptr fi
)
2958 get_frame_type (frame_info_ptr frame
)
2960 if (frame
->unwind
== NULL
)
2961 /* Initialize the frame's unwinder because that's what
2962 provides the frame's type. */
2963 frame_unwind_find_by_frame (frame
, &frame
->prologue_cache
);
2964 return frame
->unwind
->type
;
2967 struct program_space
*
2968 get_frame_program_space (frame_info_ptr frame
)
2970 return frame
->pspace
;
2973 struct program_space
*
2974 frame_unwind_program_space (frame_info_ptr this_frame
)
2976 gdb_assert (this_frame
);
2978 /* This is really a placeholder to keep the API consistent --- we
2979 assume for now that we don't have frame chains crossing
2981 return this_frame
->pspace
;
2984 const address_space
*
2985 get_frame_address_space (frame_info_ptr frame
)
2987 return frame
->aspace
;
2990 /* Memory access methods. */
2993 get_frame_memory (frame_info_ptr this_frame
, CORE_ADDR addr
,
2994 gdb::array_view
<gdb_byte
> buffer
)
2996 read_memory (addr
, buffer
.data (), buffer
.size ());
3000 get_frame_memory_signed (frame_info_ptr this_frame
, CORE_ADDR addr
,
3003 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
3004 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
3006 return read_memory_integer (addr
, len
, byte_order
);
3010 get_frame_memory_unsigned (frame_info_ptr this_frame
, CORE_ADDR addr
,
3013 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
3014 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
3016 return read_memory_unsigned_integer (addr
, len
, byte_order
);
3020 safe_frame_unwind_memory (frame_info_ptr this_frame
,
3021 CORE_ADDR addr
, gdb::array_view
<gdb_byte
> buffer
)
3023 /* NOTE: target_read_memory returns zero on success! */
3024 return target_read_memory (addr
, buffer
.data (), buffer
.size ()) == 0;
3027 /* Architecture methods. */
3030 get_frame_arch (frame_info_ptr this_frame
)
3032 return frame_unwind_arch (frame_info_ptr (this_frame
->next
));
3036 frame_unwind_arch (frame_info_ptr next_frame
)
3038 if (!next_frame
->prev_arch
.p
)
3040 struct gdbarch
*arch
;
3042 if (next_frame
->unwind
== NULL
)
3043 frame_unwind_find_by_frame (next_frame
, &next_frame
->prologue_cache
);
3045 if (next_frame
->unwind
->prev_arch
!= NULL
)
3046 arch
= next_frame
->unwind
->prev_arch (next_frame
,
3047 &next_frame
->prologue_cache
);
3049 arch
= get_frame_arch (next_frame
);
3051 next_frame
->prev_arch
.arch
= arch
;
3052 next_frame
->prev_arch
.p
= true;
3053 frame_debug_printf ("next_frame=%d -> %s",
3055 gdbarch_bfd_arch_info (arch
)->printable_name
);
3058 return next_frame
->prev_arch
.arch
;
3062 frame_unwind_caller_arch (frame_info_ptr next_frame
)
3064 next_frame
= skip_artificial_frames (next_frame
);
3066 /* We must have a non-artificial frame. The caller is supposed to check
3067 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
3069 gdb_assert (next_frame
!= NULL
);
3071 return frame_unwind_arch (next_frame
);
3074 /* Gets the language of FRAME. */
3077 get_frame_language (frame_info_ptr frame
)
3082 gdb_assert (frame
!= NULL
);
3084 /* We determine the current frame language by looking up its
3085 associated symtab. To retrieve this symtab, we use the frame
3086 PC. However we cannot use the frame PC as is, because it
3087 usually points to the instruction following the "call", which
3088 is sometimes the first instruction of another function. So
3089 we rely on get_frame_address_in_block(), it provides us with
3090 a PC that is guaranteed to be inside the frame's code
3095 pc
= get_frame_address_in_block (frame
);
3098 catch (const gdb_exception_error
&ex
)
3100 if (ex
.error
!= NOT_AVAILABLE_ERROR
)
3106 struct compunit_symtab
*cust
= find_pc_compunit_symtab (pc
);
3109 return cust
->language ();
3112 return language_unknown
;
3115 /* Stack pointer methods. */
3118 get_frame_sp (frame_info_ptr this_frame
)
3120 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
3122 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
3123 operate on THIS_FRAME now. */
3124 return gdbarch_unwind_sp (gdbarch
, frame_info_ptr (this_frame
->next
));
3130 frame_follow_static_link (frame_info_ptr frame
)
3132 const block
*frame_block
= get_frame_block (frame
, nullptr);
3133 frame_block
= frame_block
->function_block ();
3135 const struct dynamic_prop
*static_link
= frame_block
->static_link ();
3136 if (static_link
== nullptr)
3139 CORE_ADDR upper_frame_base
;
3141 if (!dwarf2_evaluate_property (static_link
, frame
, NULL
, &upper_frame_base
))
3144 /* Now climb up the stack frame until we reach the frame we are interested
3146 for (; frame
!= nullptr; frame
= get_prev_frame (frame
))
3148 struct symbol
*framefunc
= get_frame_function (frame
);
3150 /* Stacks can be quite deep: give the user a chance to stop this. */
3153 /* If we don't know how to compute FRAME's base address, don't give up:
3154 maybe the frame we are looking for is upper in the stack frame. */
3155 if (framefunc
!= NULL
3156 && SYMBOL_BLOCK_OPS (framefunc
) != NULL
3157 && SYMBOL_BLOCK_OPS (framefunc
)->get_frame_base
!= NULL
3158 && (SYMBOL_BLOCK_OPS (framefunc
)->get_frame_base (framefunc
, frame
)
3159 == upper_frame_base
))
3166 /* Return the reason why we can't unwind past FRAME. */
3168 enum unwind_stop_reason
3169 get_frame_unwind_stop_reason (frame_info_ptr frame
)
3171 /* Fill-in STOP_REASON. */
3172 get_prev_frame_always (frame
);
3173 gdb_assert (frame
->prev_p
);
3175 return frame
->stop_reason
;
3178 /* Return a string explaining REASON. */
3181 unwind_stop_reason_to_string (enum unwind_stop_reason reason
)
3185 #define SET(name, description) \
3186 case name: return _(description);
3187 #include "unwind_stop_reasons.def"
3191 internal_error ("Invalid frame stop reason");
3196 frame_stop_reason_string (frame_info_ptr fi
)
3198 gdb_assert (fi
->prev_p
);
3199 gdb_assert (fi
->prev
== NULL
);
3201 /* Return the specific string if we have one. */
3202 if (fi
->stop_string
!= NULL
)
3203 return fi
->stop_string
;
3205 /* Return the generic string if we have nothing better. */
3206 return unwind_stop_reason_to_string (fi
->stop_reason
);
3209 /* Return the enum symbol name of REASON as a string, to use in debug
3213 frame_stop_reason_symbol_string (enum unwind_stop_reason reason
)
3217 #define SET(name, description) \
3218 case name: return #name;
3219 #include "unwind_stop_reasons.def"
3223 internal_error ("Invalid frame stop reason");
3227 /* Clean up after a failed (wrong unwinder) attempt to unwind past
3231 frame_cleanup_after_sniffer (frame_info_ptr frame
)
3233 /* The sniffer should not allocate a prologue cache if it did not
3234 match this frame. */
3235 gdb_assert (frame
->prologue_cache
== NULL
);
3237 /* No sniffer should extend the frame chain; sniff based on what is
3239 gdb_assert (!frame
->prev_p
);
3241 /* The sniffer should not check the frame's ID; that's circular. */
3242 gdb_assert (frame
->this_id
.p
!= frame_id_status::COMPUTED
);
3244 /* Clear cached fields dependent on the unwinder.
3246 The previous PC is independent of the unwinder, but the previous
3247 function is not (see get_frame_address_in_block). */
3248 frame
->prev_func
.status
= CC_UNKNOWN
;
3249 frame
->prev_func
.addr
= 0;
3251 /* Discard the unwinder last, so that we can easily find it if an assertion
3252 in this function triggers. */
3253 frame
->unwind
= NULL
;
3256 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
3257 If sniffing fails, the caller should be sure to call
3258 frame_cleanup_after_sniffer. */
3261 frame_prepare_for_sniffer (frame_info_ptr frame
,
3262 const struct frame_unwind
*unwind
)
3264 gdb_assert (frame
->unwind
== NULL
);
3265 frame
->unwind
= unwind
;
3268 static struct cmd_list_element
*set_backtrace_cmdlist
;
3269 static struct cmd_list_element
*show_backtrace_cmdlist
;
3271 /* Definition of the "set backtrace" settings that are exposed as
3272 "backtrace" command options. */
3274 using boolean_option_def
3275 = gdb::option::boolean_option_def
<set_backtrace_options
>;
3277 const gdb::option::option_def set_backtrace_option_defs
[] = {
3279 boolean_option_def
{
3281 [] (set_backtrace_options
*opt
) { return &opt
->backtrace_past_main
; },
3282 show_backtrace_past_main
, /* show_cmd_cb */
3283 N_("Set whether backtraces should continue past \"main\"."),
3284 N_("Show whether backtraces should continue past \"main\"."),
3285 N_("Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
3286 the backtrace at \"main\". Set this if you need to see the rest\n\
3287 of the stack trace."),
3290 boolean_option_def
{
3292 [] (set_backtrace_options
*opt
) { return &opt
->backtrace_past_entry
; },
3293 show_backtrace_past_entry
, /* show_cmd_cb */
3294 N_("Set whether backtraces should continue past the entry point of a program."),
3295 N_("Show whether backtraces should continue past the entry point of a program."),
3296 N_("Normally there are no callers beyond the entry point of a program, so GDB\n\
3297 will terminate the backtrace there. Set this if you need to see\n\
3298 the rest of the stack trace."),
3302 /* Implement the 'maintenance print frame-id' command. */
3305 maintenance_print_frame_id (const char *args
, int from_tty
)
3307 frame_info_ptr frame
;
3309 /* Use the currently selected frame, or select a frame based on the level
3310 number passed by the user. */
3311 if (args
== nullptr)
3312 frame
= get_selected_frame ("No frame selected");
3315 int level
= value_as_long (parse_and_eval (args
));
3316 frame
= find_relative_frame (get_current_frame (), &level
);
3319 /* Print the frame-id. */
3320 gdb_assert (frame
!= nullptr);
3321 gdb_printf ("frame-id for frame #%d: %s\n",
3322 frame_relative_level (frame
),
3323 get_frame_id (frame
).to_string ().c_str ());
3326 /* See frame-info-ptr.h. */
3328 frame_info_ptr::frame_info_ptr (struct frame_info
*ptr
)
3331 frame_list
.push_back (*this);
3333 if (m_ptr
== nullptr)
3336 m_cached_level
= ptr
->level
;
3338 if (m_cached_level
!= 0 || m_ptr
->this_id
.value
.user_created_p
)
3339 m_cached_id
= m_ptr
->this_id
.value
;
3342 /* See frame-info-ptr.h. */
3345 frame_info_ptr::reinflate () const
3347 /* Ensure we have a valid frame level (sentinel frame or above). */
3348 gdb_assert (m_cached_level
>= -1);
3350 if (m_ptr
!= nullptr)
3352 /* The frame_info wasn't invalidated, no need to reinflate. */
3356 if (m_cached_id
.user_created_p
)
3357 m_ptr
= create_new_frame (m_cached_id
).get ();
3360 /* Frame #0 needs special handling, see comment in select_frame. */
3361 if (m_cached_level
== 0)
3362 m_ptr
= get_current_frame ().get ();
3365 /* If we reach here without a valid frame id, it means we are trying
3366 to reinflate a frame whose id was not know at construction time.
3367 We're probably trying to reinflate a frame while computing its id
3368 which is not possible, and would indicate a problem with GDB. */
3369 gdb_assert (frame_id_p (m_cached_id
));
3370 m_ptr
= frame_find_by_id (m_cached_id
).get ();
3374 gdb_assert (m_ptr
!= nullptr);
3378 void _initialize_frame ();
3380 _initialize_frame ()
3382 obstack_init (&frame_cache_obstack
);
3384 frame_stash_create ();
3386 gdb::observers::target_changed
.attach (frame_observer_target_changed
,
3389 add_setshow_prefix_cmd ("backtrace", class_maintenance
,
3391 Set backtrace specific variables.\n\
3392 Configure backtrace variables such as the backtrace limit"),
3394 Show backtrace specific variables.\n\
3395 Show backtrace variables such as the backtrace limit."),
3396 &set_backtrace_cmdlist
, &show_backtrace_cmdlist
,
3397 &setlist
, &showlist
);
3399 add_setshow_uinteger_cmd ("limit", class_obscure
,
3400 &user_set_backtrace_options
.backtrace_limit
, _("\
3401 Set an upper bound on the number of backtrace levels."), _("\
3402 Show the upper bound on the number of backtrace levels."), _("\
3403 No more than the specified number of frames can be displayed or examined.\n\
3404 Literal \"unlimited\" or zero means no limit."),
3406 show_backtrace_limit
,
3407 &set_backtrace_cmdlist
,
3408 &show_backtrace_cmdlist
);
3410 gdb::option::add_setshow_cmds_for_options
3411 (class_stack
, &user_set_backtrace_options
,
3412 set_backtrace_option_defs
, &set_backtrace_cmdlist
, &show_backtrace_cmdlist
);
3414 /* Debug this files internals. */
3415 add_setshow_boolean_cmd ("frame", class_maintenance
, &frame_debug
, _("\
3416 Set frame debugging."), _("\
3417 Show frame debugging."), _("\
3418 When non-zero, frame specific internal debugging is enabled."),
3421 &setdebuglist
, &showdebuglist
);
3423 add_cmd ("frame-id", class_maintenance
, maintenance_print_frame_id
,
3424 _("Print the current frame-id."),
3425 &maintenanceprintlist
);