1 /* Cache and manage frames for GDB, the GNU debugger.
3 Copyright (C) 1986-2017 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "inferior.h" /* for inferior_ptid */
26 #include "user-regs.h"
27 #include "gdb_obstack.h"
28 #include "dummy-frame.h"
29 #include "sentinel-frame.h"
33 #include "frame-unwind.h"
34 #include "frame-base.h"
39 #include "gdbthread.h"
41 #include "inline-frame.h"
42 #include "tracepoint.h"
46 /* The sentinel frame terminates the innermost end of the frame chain.
47 If unwound, it returns the information needed to construct an
50 The current frame, which is the innermost frame, can be found at
51 sentinel_frame->prev. */
53 static struct frame_info *sentinel_frame;
55 static struct frame_info *get_prev_frame_raw (struct frame_info *this_frame);
56 static const char *frame_stop_reason_symbol_string (enum unwind_stop_reason reason);
58 /* Status of some values cached in the frame_info object. */
60 enum cached_copy_status
62 /* Value is unknown. */
65 /* We have a value. */
68 /* Value was not saved. */
71 /* Value is unavailable. */
75 /* We keep a cache of stack frames, each of which is a "struct
76 frame_info". The innermost one gets allocated (in
77 wait_for_inferior) each time the inferior stops; sentinel_frame
78 points to it. Additional frames get allocated (in get_prev_frame)
79 as needed, and are chained through the next and prev fields. Any
80 time that the frame cache becomes invalid (most notably when we
81 execute something, but also if we change how we interpret the
82 frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything
83 which reads new symbols)), we should call reinit_frame_cache. */
87 /* Level of this frame. The inner-most (youngest) frame is at level
88 0. As you move towards the outer-most (oldest) frame, the level
89 increases. This is a cached value. It could just as easily be
90 computed by counting back from the selected frame to the inner
92 /* NOTE: cagney/2002-04-05: Perhaps a level of ``-1'' should be
93 reserved to indicate a bogus frame - one that has been created
94 just to keep GDB happy (GDB always needs a frame). For the
95 moment leave this as speculation. */
98 /* The frame's program space. */
99 struct program_space *pspace;
101 /* The frame's address space. */
102 struct address_space *aspace;
104 /* The frame's low-level unwinder and corresponding cache. The
105 low-level unwinder is responsible for unwinding register values
106 for the previous frame. The low-level unwind methods are
107 selected based on the presence, or otherwise, of register unwind
108 information such as CFI. */
109 void *prologue_cache;
110 const struct frame_unwind *unwind;
112 /* Cached copy of the previous frame's architecture. */
116 struct gdbarch *arch;
119 /* Cached copy of the previous frame's resume address. */
121 enum cached_copy_status status;
125 /* Cached copy of the previous frame's function address. */
132 /* This frame's ID. */
136 struct frame_id value;
139 /* The frame's high-level base methods, and corresponding cache.
140 The high level base methods are selected based on the frame's
142 const struct frame_base *base;
145 /* Pointers to the next (down, inner, younger) and previous (up,
146 outer, older) frame_info's in the frame cache. */
147 struct frame_info *next; /* down, inner, younger */
149 struct frame_info *prev; /* up, outer, older */
151 /* The reason why we could not set PREV, or UNWIND_NO_REASON if we
152 could. Only valid when PREV_P is set. */
153 enum unwind_stop_reason stop_reason;
155 /* A frame specific string describing the STOP_REASON in more detail.
156 Only valid when PREV_P is set, but even then may still be NULL. */
157 const char *stop_string;
160 /* A frame stash used to speed up frame lookups. Create a hash table
161 to stash frames previously accessed from the frame cache for
162 quicker subsequent retrieval. The hash table is emptied whenever
163 the frame cache is invalidated. */
165 static htab_t frame_stash;
167 /* Internal function to calculate a hash from the frame_id addresses,
168 using as many valid addresses as possible. Frames below level 0
169 are not stored in the hash table. */
172 frame_addr_hash (const void *ap)
174 const struct frame_info *frame = (const struct frame_info *) ap;
175 const struct frame_id f_id = frame->this_id.value;
178 gdb_assert (f_id.stack_status != FID_STACK_INVALID
180 || f_id.special_addr_p);
182 if (f_id.stack_status == FID_STACK_VALID)
183 hash = iterative_hash (&f_id.stack_addr,
184 sizeof (f_id.stack_addr), hash);
185 if (f_id.code_addr_p)
186 hash = iterative_hash (&f_id.code_addr,
187 sizeof (f_id.code_addr), hash);
188 if (f_id.special_addr_p)
189 hash = iterative_hash (&f_id.special_addr,
190 sizeof (f_id.special_addr), hash);
195 /* Internal equality function for the hash table. This function
196 defers equality operations to frame_id_eq. */
199 frame_addr_hash_eq (const void *a, const void *b)
201 const struct frame_info *f_entry = (const struct frame_info *) a;
202 const struct frame_info *f_element = (const struct frame_info *) b;
204 return frame_id_eq (f_entry->this_id.value,
205 f_element->this_id.value);
208 /* Internal function to create the frame_stash hash table. 100 seems
209 to be a good compromise to start the hash table at. */
212 frame_stash_create (void)
214 frame_stash = htab_create (100,
220 /* Internal function to add a frame to the frame_stash hash table.
221 Returns false if a frame with the same ID was already stashed, true
225 frame_stash_add (struct frame_info *frame)
227 struct frame_info **slot;
229 /* Do not try to stash the sentinel frame. */
230 gdb_assert (frame->level >= 0);
232 slot = (struct frame_info **) htab_find_slot (frame_stash,
236 /* If we already have a frame in the stack with the same id, we
237 either have a stack cycle (corrupted stack?), or some bug
238 elsewhere in GDB. In any case, ignore the duplicate and return
239 an indication to the caller. */
247 /* Internal function to search the frame stash for an entry with the
248 given frame ID. If found, return that frame. Otherwise return
251 static struct frame_info *
252 frame_stash_find (struct frame_id id)
254 struct frame_info dummy;
255 struct frame_info *frame;
257 dummy.this_id.value = id;
258 frame = (struct frame_info *) htab_find (frame_stash, &dummy);
262 /* Internal function to invalidate the frame stash by removing all
263 entries in it. This only occurs when the frame cache is
267 frame_stash_invalidate (void)
269 htab_empty (frame_stash);
272 /* Flag to control debugging. */
274 unsigned int frame_debug;
276 show_frame_debug (struct ui_file *file, int from_tty,
277 struct cmd_list_element *c, const char *value)
279 fprintf_filtered (file, _("Frame debugging is %s.\n"), value);
282 /* Flag to indicate whether backtraces should stop at main et.al. */
284 static int backtrace_past_main;
286 show_backtrace_past_main (struct ui_file *file, int from_tty,
287 struct cmd_list_element *c, const char *value)
289 fprintf_filtered (file,
290 _("Whether backtraces should "
291 "continue past \"main\" is %s.\n"),
295 static int backtrace_past_entry;
297 show_backtrace_past_entry (struct ui_file *file, int from_tty,
298 struct cmd_list_element *c, const char *value)
300 fprintf_filtered (file, _("Whether backtraces should continue past the "
301 "entry point of a program is %s.\n"),
305 static unsigned int backtrace_limit = UINT_MAX;
307 show_backtrace_limit (struct ui_file *file, int from_tty,
308 struct cmd_list_element *c, const char *value)
310 fprintf_filtered (file,
311 _("An upper bound on the number "
312 "of backtrace levels is %s.\n"),
318 fprint_field (struct ui_file *file, const char *name, int p, CORE_ADDR addr)
321 fprintf_unfiltered (file, "%s=%s", name, hex_string (addr));
323 fprintf_unfiltered (file, "!%s", name);
327 fprint_frame_id (struct ui_file *file, struct frame_id id)
329 fprintf_unfiltered (file, "{");
331 if (id.stack_status == FID_STACK_INVALID)
332 fprintf_unfiltered (file, "!stack");
333 else if (id.stack_status == FID_STACK_UNAVAILABLE)
334 fprintf_unfiltered (file, "stack=<unavailable>");
335 else if (id.stack_status == FID_STACK_SENTINEL)
336 fprintf_unfiltered (file, "stack=<sentinel>");
338 fprintf_unfiltered (file, "stack=%s", hex_string (id.stack_addr));
339 fprintf_unfiltered (file, ",");
341 fprint_field (file, "code", id.code_addr_p, id.code_addr);
342 fprintf_unfiltered (file, ",");
344 fprint_field (file, "special", id.special_addr_p, id.special_addr);
346 if (id.artificial_depth)
347 fprintf_unfiltered (file, ",artificial=%d", id.artificial_depth);
349 fprintf_unfiltered (file, "}");
353 fprint_frame_type (struct ui_file *file, enum frame_type type)
358 fprintf_unfiltered (file, "NORMAL_FRAME");
361 fprintf_unfiltered (file, "DUMMY_FRAME");
364 fprintf_unfiltered (file, "INLINE_FRAME");
367 fprintf_unfiltered (file, "TAILCALL_FRAME");
370 fprintf_unfiltered (file, "SIGTRAMP_FRAME");
373 fprintf_unfiltered (file, "ARCH_FRAME");
376 fprintf_unfiltered (file, "SENTINEL_FRAME");
379 fprintf_unfiltered (file, "<unknown type>");
385 fprint_frame (struct ui_file *file, struct frame_info *fi)
389 fprintf_unfiltered (file, "<NULL frame>");
392 fprintf_unfiltered (file, "{");
393 fprintf_unfiltered (file, "level=%d", fi->level);
394 fprintf_unfiltered (file, ",");
395 fprintf_unfiltered (file, "type=");
396 if (fi->unwind != NULL)
397 fprint_frame_type (file, fi->unwind->type);
399 fprintf_unfiltered (file, "<unknown>");
400 fprintf_unfiltered (file, ",");
401 fprintf_unfiltered (file, "unwind=");
402 if (fi->unwind != NULL)
403 gdb_print_host_address (fi->unwind, file);
405 fprintf_unfiltered (file, "<unknown>");
406 fprintf_unfiltered (file, ",");
407 fprintf_unfiltered (file, "pc=");
408 if (fi->next == NULL || fi->next->prev_pc.status == CC_UNKNOWN)
409 fprintf_unfiltered (file, "<unknown>");
410 else if (fi->next->prev_pc.status == CC_VALUE)
411 fprintf_unfiltered (file, "%s",
412 hex_string (fi->next->prev_pc.value));
413 else if (fi->next->prev_pc.status == CC_NOT_SAVED)
414 val_print_not_saved (file);
415 else if (fi->next->prev_pc.status == CC_UNAVAILABLE)
416 val_print_unavailable (file);
417 fprintf_unfiltered (file, ",");
418 fprintf_unfiltered (file, "id=");
420 fprint_frame_id (file, fi->this_id.value);
422 fprintf_unfiltered (file, "<unknown>");
423 fprintf_unfiltered (file, ",");
424 fprintf_unfiltered (file, "func=");
425 if (fi->next != NULL && fi->next->prev_func.p)
426 fprintf_unfiltered (file, "%s", hex_string (fi->next->prev_func.addr));
428 fprintf_unfiltered (file, "<unknown>");
429 fprintf_unfiltered (file, "}");
432 /* Given FRAME, return the enclosing frame as found in real frames read-in from
433 inferior memory. Skip any previous frames which were made up by GDB.
434 Return FRAME if FRAME is a non-artificial frame.
435 Return NULL if FRAME is the start of an artificial-only chain. */
437 static struct frame_info *
438 skip_artificial_frames (struct frame_info *frame)
440 /* Note we use get_prev_frame_always, and not get_prev_frame. The
441 latter will truncate the frame chain, leading to this function
442 unintentionally returning a null_frame_id (e.g., when the user
443 sets a backtrace limit).
445 Note that for record targets we may get a frame chain that consists
446 of artificial frames only. */
447 while (get_frame_type (frame) == INLINE_FRAME
448 || get_frame_type (frame) == TAILCALL_FRAME)
450 frame = get_prev_frame_always (frame);
459 skip_unwritable_frames (struct frame_info *frame)
461 while (gdbarch_code_of_frame_writable (get_frame_arch (frame), frame) == 0)
463 frame = get_prev_frame (frame);
474 skip_tailcall_frames (struct frame_info *frame)
476 while (get_frame_type (frame) == TAILCALL_FRAME)
478 /* Note that for record targets we may get a frame chain that consists of
479 tailcall frames only. */
480 frame = get_prev_frame (frame);
488 /* Compute the frame's uniq ID that can be used to, later, re-find the
492 compute_frame_id (struct frame_info *fi)
494 gdb_assert (!fi->this_id.p);
497 fprintf_unfiltered (gdb_stdlog, "{ compute_frame_id (fi=%d) ",
499 /* Find the unwinder. */
500 if (fi->unwind == NULL)
501 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
502 /* Find THIS frame's ID. */
503 /* Default to outermost if no ID is found. */
504 fi->this_id.value = outer_frame_id;
505 fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value);
506 gdb_assert (frame_id_p (fi->this_id.value));
510 fprintf_unfiltered (gdb_stdlog, "-> ");
511 fprint_frame_id (gdb_stdlog, fi->this_id.value);
512 fprintf_unfiltered (gdb_stdlog, " }\n");
516 /* Return a frame uniq ID that can be used to, later, re-find the
520 get_frame_id (struct frame_info *fi)
523 return null_frame_id;
529 /* If we haven't computed the frame id yet, then it must be that
530 this is the current frame. Compute it now, and stash the
531 result. The IDs of other frames are computed as soon as
532 they're created, in order to detect cycles. See
533 get_prev_frame_if_no_cycle. */
534 gdb_assert (fi->level == 0);
537 compute_frame_id (fi);
539 /* Since this is the first frame in the chain, this should
541 stashed = frame_stash_add (fi);
542 gdb_assert (stashed);
545 return fi->this_id.value;
549 get_stack_frame_id (struct frame_info *next_frame)
551 return get_frame_id (skip_artificial_frames (next_frame));
555 frame_unwind_caller_id (struct frame_info *next_frame)
557 struct frame_info *this_frame;
559 /* Use get_prev_frame_always, and not get_prev_frame. The latter
560 will truncate the frame chain, leading to this function
561 unintentionally returning a null_frame_id (e.g., when a caller
562 requests the frame ID of "main()"s caller. */
564 next_frame = skip_artificial_frames (next_frame);
565 if (next_frame == NULL)
566 return null_frame_id;
568 this_frame = get_prev_frame_always (next_frame);
570 return get_frame_id (skip_artificial_frames (this_frame));
572 return null_frame_id;
575 const struct frame_id null_frame_id = { 0 }; /* All zeros. */
576 const struct frame_id sentinel_frame_id = { 0, 0, 0, FID_STACK_SENTINEL, 0, 1, 0 };
577 const struct frame_id outer_frame_id = { 0, 0, 0, FID_STACK_INVALID, 0, 1, 0 };
580 frame_id_build_special (CORE_ADDR stack_addr, CORE_ADDR code_addr,
581 CORE_ADDR special_addr)
583 struct frame_id id = null_frame_id;
585 id.stack_addr = stack_addr;
586 id.stack_status = FID_STACK_VALID;
587 id.code_addr = code_addr;
589 id.special_addr = special_addr;
590 id.special_addr_p = 1;
597 frame_id_build_unavailable_stack (CORE_ADDR code_addr)
599 struct frame_id id = null_frame_id;
601 id.stack_status = FID_STACK_UNAVAILABLE;
602 id.code_addr = code_addr;
610 frame_id_build_unavailable_stack_special (CORE_ADDR code_addr,
611 CORE_ADDR special_addr)
613 struct frame_id id = null_frame_id;
615 id.stack_status = FID_STACK_UNAVAILABLE;
616 id.code_addr = code_addr;
618 id.special_addr = special_addr;
619 id.special_addr_p = 1;
624 frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr)
626 struct frame_id id = null_frame_id;
628 id.stack_addr = stack_addr;
629 id.stack_status = FID_STACK_VALID;
630 id.code_addr = code_addr;
636 frame_id_build_wild (CORE_ADDR stack_addr)
638 struct frame_id id = null_frame_id;
640 id.stack_addr = stack_addr;
641 id.stack_status = FID_STACK_VALID;
646 frame_id_p (struct frame_id l)
650 /* The frame is valid iff it has a valid stack address. */
651 p = l.stack_status != FID_STACK_INVALID;
652 /* outer_frame_id is also valid. */
653 if (!p && memcmp (&l, &outer_frame_id, sizeof (l)) == 0)
657 fprintf_unfiltered (gdb_stdlog, "{ frame_id_p (l=");
658 fprint_frame_id (gdb_stdlog, l);
659 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", p);
665 frame_id_artificial_p (struct frame_id l)
670 return (l.artificial_depth != 0);
674 frame_id_eq (struct frame_id l, struct frame_id r)
678 if (l.stack_status == FID_STACK_INVALID && l.special_addr_p
679 && r.stack_status == FID_STACK_INVALID && r.special_addr_p)
680 /* The outermost frame marker is equal to itself. This is the
681 dodgy thing about outer_frame_id, since between execution steps
682 we might step into another function - from which we can't
683 unwind either. More thought required to get rid of
686 else if (l.stack_status == FID_STACK_INVALID
687 || r.stack_status == FID_STACK_INVALID)
688 /* Like a NaN, if either ID is invalid, the result is false.
689 Note that a frame ID is invalid iff it is the null frame ID. */
691 else if (l.stack_status != r.stack_status || l.stack_addr != r.stack_addr)
692 /* If .stack addresses are different, the frames are different. */
694 else if (l.code_addr_p && r.code_addr_p && l.code_addr != r.code_addr)
695 /* An invalid code addr is a wild card. If .code addresses are
696 different, the frames are different. */
698 else if (l.special_addr_p && r.special_addr_p
699 && l.special_addr != r.special_addr)
700 /* An invalid special addr is a wild card (or unused). Otherwise
701 if special addresses are different, the frames are different. */
703 else if (l.artificial_depth != r.artificial_depth)
704 /* If artifical depths are different, the frames must be different. */
707 /* Frames are equal. */
712 fprintf_unfiltered (gdb_stdlog, "{ frame_id_eq (l=");
713 fprint_frame_id (gdb_stdlog, l);
714 fprintf_unfiltered (gdb_stdlog, ",r=");
715 fprint_frame_id (gdb_stdlog, r);
716 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", eq);
721 /* Safety net to check whether frame ID L should be inner to
722 frame ID R, according to their stack addresses.
724 This method cannot be used to compare arbitrary frames, as the
725 ranges of valid stack addresses may be discontiguous (e.g. due
728 However, it can be used as safety net to discover invalid frame
729 IDs in certain circumstances. Assuming that NEXT is the immediate
730 inner frame to THIS and that NEXT and THIS are both NORMAL frames:
732 * The stack address of NEXT must be inner-than-or-equal to the stack
735 Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind
738 * If NEXT and THIS have different stack addresses, no other frame
739 in the frame chain may have a stack address in between.
741 Therefore, if frame_id_inner (TEST, THIS) holds, but
742 frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer
743 to a valid frame in the frame chain.
745 The sanity checks above cannot be performed when a SIGTRAMP frame
746 is involved, because signal handlers might be executed on a different
747 stack than the stack used by the routine that caused the signal
748 to be raised. This can happen for instance when a thread exceeds
749 its maximum stack size. In this case, certain compilers implement
750 a stack overflow strategy that cause the handler to be run on a
754 frame_id_inner (struct gdbarch *gdbarch, struct frame_id l, struct frame_id r)
758 if (l.stack_status != FID_STACK_VALID || r.stack_status != FID_STACK_VALID)
759 /* Like NaN, any operation involving an invalid ID always fails.
760 Likewise if either ID has an unavailable stack address. */
762 else if (l.artificial_depth > r.artificial_depth
763 && l.stack_addr == r.stack_addr
764 && l.code_addr_p == r.code_addr_p
765 && l.special_addr_p == r.special_addr_p
766 && l.special_addr == r.special_addr)
768 /* Same function, different inlined functions. */
769 const struct block *lb, *rb;
771 gdb_assert (l.code_addr_p && r.code_addr_p);
773 lb = block_for_pc (l.code_addr);
774 rb = block_for_pc (r.code_addr);
776 if (lb == NULL || rb == NULL)
777 /* Something's gone wrong. */
780 /* This will return true if LB and RB are the same block, or
781 if the block with the smaller depth lexically encloses the
782 block with the greater depth. */
783 inner = contained_in (lb, rb);
786 /* Only return non-zero when strictly inner than. Note that, per
787 comment in "frame.h", there is some fuzz here. Frameless
788 functions are not strictly inner than (same .stack but
789 different .code and/or .special address). */
790 inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr);
793 fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l=");
794 fprint_frame_id (gdb_stdlog, l);
795 fprintf_unfiltered (gdb_stdlog, ",r=");
796 fprint_frame_id (gdb_stdlog, r);
797 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", inner);
803 frame_find_by_id (struct frame_id id)
805 struct frame_info *frame, *prev_frame;
807 /* ZERO denotes the null frame, let the caller decide what to do
808 about it. Should it instead return get_current_frame()? */
809 if (!frame_id_p (id))
812 /* Check for the sentinel frame. */
813 if (frame_id_eq (id, sentinel_frame_id))
814 return sentinel_frame;
816 /* Try using the frame stash first. Finding it there removes the need
817 to perform the search by looping over all frames, which can be very
818 CPU-intensive if the number of frames is very high (the loop is O(n)
819 and get_prev_frame performs a series of checks that are relatively
820 expensive). This optimization is particularly useful when this function
821 is called from another function (such as value_fetch_lazy, case
822 VALUE_LVAL (val) == lval_register) which already loops over all frames,
823 making the overall behavior O(n^2). */
824 frame = frame_stash_find (id);
828 for (frame = get_current_frame (); ; frame = prev_frame)
830 struct frame_id self = get_frame_id (frame);
832 if (frame_id_eq (id, self))
833 /* An exact match. */
836 prev_frame = get_prev_frame (frame);
840 /* As a safety net to avoid unnecessary backtracing while trying
841 to find an invalid ID, we check for a common situation where
842 we can detect from comparing stack addresses that no other
843 frame in the current frame chain can have this ID. See the
844 comment at frame_id_inner for details. */
845 if (get_frame_type (frame) == NORMAL_FRAME
846 && !frame_id_inner (get_frame_arch (frame), id, self)
847 && frame_id_inner (get_frame_arch (prev_frame), id,
848 get_frame_id (prev_frame)))
855 frame_unwind_pc (struct frame_info *this_frame)
857 if (this_frame->prev_pc.status == CC_UNKNOWN)
859 if (gdbarch_unwind_pc_p (frame_unwind_arch (this_frame)))
861 struct gdbarch *prev_gdbarch;
865 /* The right way. The `pure' way. The one true way. This
866 method depends solely on the register-unwind code to
867 determine the value of registers in THIS frame, and hence
868 the value of this frame's PC (resume address). A typical
869 implementation is no more than:
871 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf);
872 return extract_unsigned_integer (buf, size of ISA_PC_REGNUM);
874 Note: this method is very heavily dependent on a correct
875 register-unwind implementation, it pays to fix that
876 method first; this method is frame type agnostic, since
877 it only deals with register values, it works with any
878 frame. This is all in stark contrast to the old
879 FRAME_SAVED_PC which would try to directly handle all the
880 different ways that a PC could be unwound. */
881 prev_gdbarch = frame_unwind_arch (this_frame);
885 pc = gdbarch_unwind_pc (prev_gdbarch, this_frame);
888 CATCH (ex, RETURN_MASK_ERROR)
890 if (ex.error == NOT_AVAILABLE_ERROR)
892 this_frame->prev_pc.status = CC_UNAVAILABLE;
895 fprintf_unfiltered (gdb_stdlog,
896 "{ frame_unwind_pc (this_frame=%d)"
897 " -> <unavailable> }\n",
900 else if (ex.error == OPTIMIZED_OUT_ERROR)
902 this_frame->prev_pc.status = CC_NOT_SAVED;
905 fprintf_unfiltered (gdb_stdlog,
906 "{ frame_unwind_pc (this_frame=%d)"
907 " -> <not saved> }\n",
911 throw_exception (ex);
917 this_frame->prev_pc.value = pc;
918 this_frame->prev_pc.status = CC_VALUE;
920 fprintf_unfiltered (gdb_stdlog,
921 "{ frame_unwind_pc (this_frame=%d) "
924 hex_string (this_frame->prev_pc.value));
928 internal_error (__FILE__, __LINE__, _("No unwind_pc method"));
931 if (this_frame->prev_pc.status == CC_VALUE)
932 return this_frame->prev_pc.value;
933 else if (this_frame->prev_pc.status == CC_UNAVAILABLE)
934 throw_error (NOT_AVAILABLE_ERROR, _("PC not available"));
935 else if (this_frame->prev_pc.status == CC_NOT_SAVED)
936 throw_error (OPTIMIZED_OUT_ERROR, _("PC not saved"));
938 internal_error (__FILE__, __LINE__,
939 "unexpected prev_pc status: %d",
940 (int) this_frame->prev_pc.status);
944 frame_unwind_caller_pc (struct frame_info *this_frame)
946 this_frame = skip_artificial_frames (this_frame);
948 /* We must have a non-artificial frame. The caller is supposed to check
949 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
951 gdb_assert (this_frame != NULL);
953 return frame_unwind_pc (this_frame);
957 get_frame_func_if_available (struct frame_info *this_frame, CORE_ADDR *pc)
959 struct frame_info *next_frame = this_frame->next;
961 if (!next_frame->prev_func.p)
963 CORE_ADDR addr_in_block;
965 /* Make certain that this, and not the adjacent, function is
967 if (!get_frame_address_in_block_if_available (this_frame, &addr_in_block))
969 next_frame->prev_func.p = -1;
971 fprintf_unfiltered (gdb_stdlog,
972 "{ get_frame_func (this_frame=%d)"
973 " -> unavailable }\n",
978 next_frame->prev_func.p = 1;
979 next_frame->prev_func.addr = get_pc_function_start (addr_in_block);
981 fprintf_unfiltered (gdb_stdlog,
982 "{ get_frame_func (this_frame=%d) -> %s }\n",
984 hex_string (next_frame->prev_func.addr));
988 if (next_frame->prev_func.p < 0)
995 *pc = next_frame->prev_func.addr;
1001 get_frame_func (struct frame_info *this_frame)
1005 if (!get_frame_func_if_available (this_frame, &pc))
1006 throw_error (NOT_AVAILABLE_ERROR, _("PC not available"));
1011 static enum register_status
1012 do_frame_register_read (void *src, int regnum, gdb_byte *buf)
1014 if (!deprecated_frame_register_read ((struct frame_info *) src, regnum, buf))
1015 return REG_UNAVAILABLE;
1021 frame_save_as_regcache (struct frame_info *this_frame)
1023 struct address_space *aspace = get_frame_address_space (this_frame);
1024 struct regcache *regcache = regcache_xmalloc (get_frame_arch (this_frame),
1026 struct cleanup *cleanups = make_cleanup_regcache_xfree (regcache);
1028 regcache_save (regcache, do_frame_register_read, this_frame);
1029 discard_cleanups (cleanups);
1034 frame_pop (struct frame_info *this_frame)
1036 struct frame_info *prev_frame;
1037 struct regcache *scratch;
1038 struct cleanup *cleanups;
1040 if (get_frame_type (this_frame) == DUMMY_FRAME)
1042 /* Popping a dummy frame involves restoring more than just registers.
1043 dummy_frame_pop does all the work. */
1044 dummy_frame_pop (get_frame_id (this_frame), inferior_ptid);
1048 /* Ensure that we have a frame to pop to. */
1049 prev_frame = get_prev_frame_always (this_frame);
1052 error (_("Cannot pop the initial frame."));
1054 /* Ignore TAILCALL_FRAME type frames, they were executed already before
1055 entering THISFRAME. */
1056 prev_frame = skip_tailcall_frames (prev_frame);
1058 if (prev_frame == NULL)
1059 error (_("Cannot find the caller frame."));
1061 /* Make a copy of all the register values unwound from this frame.
1062 Save them in a scratch buffer so that there isn't a race between
1063 trying to extract the old values from the current regcache while
1064 at the same time writing new values into that same cache. */
1065 scratch = frame_save_as_regcache (prev_frame);
1066 cleanups = make_cleanup_regcache_xfree (scratch);
1068 /* FIXME: cagney/2003-03-16: It should be possible to tell the
1069 target's register cache that it is about to be hit with a burst
1070 register transfer and that the sequence of register writes should
1071 be batched. The pair target_prepare_to_store() and
1072 target_store_registers() kind of suggest this functionality.
1073 Unfortunately, they don't implement it. Their lack of a formal
1074 definition can lead to targets writing back bogus values
1075 (arguably a bug in the target code mind). */
1076 /* Now copy those saved registers into the current regcache.
1077 Here, regcache_cpy() calls regcache_restore(). */
1078 regcache_cpy (get_current_regcache (), scratch);
1079 do_cleanups (cleanups);
1081 /* We've made right mess of GDB's local state, just discard
1083 reinit_frame_cache ();
1087 frame_register_unwind (struct frame_info *frame, int regnum,
1088 int *optimizedp, int *unavailablep,
1089 enum lval_type *lvalp, CORE_ADDR *addrp,
1090 int *realnump, gdb_byte *bufferp)
1092 struct value *value;
1094 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1095 that the value proper does not need to be fetched. */
1096 gdb_assert (optimizedp != NULL);
1097 gdb_assert (lvalp != NULL);
1098 gdb_assert (addrp != NULL);
1099 gdb_assert (realnump != NULL);
1100 /* gdb_assert (bufferp != NULL); */
1102 value = frame_unwind_register_value (frame, regnum);
1104 gdb_assert (value != NULL);
1106 *optimizedp = value_optimized_out (value);
1107 *unavailablep = !value_entirely_available (value);
1108 *lvalp = VALUE_LVAL (value);
1109 *addrp = value_address (value);
1110 if (*lvalp == lval_register)
1111 *realnump = VALUE_REGNUM (value);
1117 if (!*optimizedp && !*unavailablep)
1118 memcpy (bufferp, value_contents_all (value),
1119 TYPE_LENGTH (value_type (value)));
1121 memset (bufferp, 0, TYPE_LENGTH (value_type (value)));
1124 /* Dispose of the new value. This prevents watchpoints from
1125 trying to watch the saved frame pointer. */
1126 release_value (value);
1131 frame_register (struct frame_info *frame, int regnum,
1132 int *optimizedp, int *unavailablep, enum lval_type *lvalp,
1133 CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp)
1135 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1136 that the value proper does not need to be fetched. */
1137 gdb_assert (optimizedp != NULL);
1138 gdb_assert (lvalp != NULL);
1139 gdb_assert (addrp != NULL);
1140 gdb_assert (realnump != NULL);
1141 /* gdb_assert (bufferp != NULL); */
1143 /* Obtain the register value by unwinding the register from the next
1144 (more inner frame). */
1145 gdb_assert (frame != NULL && frame->next != NULL);
1146 frame_register_unwind (frame->next, regnum, optimizedp, unavailablep,
1147 lvalp, addrp, realnump, bufferp);
1151 frame_unwind_register (struct frame_info *frame, int regnum, gdb_byte *buf)
1157 enum lval_type lval;
1159 frame_register_unwind (frame, regnum, &optimized, &unavailable,
1160 &lval, &addr, &realnum, buf);
1163 throw_error (OPTIMIZED_OUT_ERROR,
1164 _("Register %d was not saved"), regnum);
1166 throw_error (NOT_AVAILABLE_ERROR,
1167 _("Register %d is not available"), regnum);
1171 get_frame_register (struct frame_info *frame,
1172 int regnum, gdb_byte *buf)
1174 frame_unwind_register (frame->next, regnum, buf);
1178 frame_unwind_register_value (struct frame_info *frame, int regnum)
1180 struct gdbarch *gdbarch;
1181 struct value *value;
1183 gdb_assert (frame != NULL);
1184 gdbarch = frame_unwind_arch (frame);
1188 fprintf_unfiltered (gdb_stdlog,
1189 "{ frame_unwind_register_value "
1190 "(frame=%d,regnum=%d(%s),...) ",
1191 frame->level, regnum,
1192 user_reg_map_regnum_to_name (gdbarch, regnum));
1195 /* Find the unwinder. */
1196 if (frame->unwind == NULL)
1197 frame_unwind_find_by_frame (frame, &frame->prologue_cache);
1199 /* Ask this frame to unwind its register. */
1200 value = frame->unwind->prev_register (frame, &frame->prologue_cache, regnum);
1204 fprintf_unfiltered (gdb_stdlog, "->");
1205 if (value_optimized_out (value))
1207 fprintf_unfiltered (gdb_stdlog, " ");
1208 val_print_optimized_out (value, gdb_stdlog);
1212 if (VALUE_LVAL (value) == lval_register)
1213 fprintf_unfiltered (gdb_stdlog, " register=%d",
1214 VALUE_REGNUM (value));
1215 else if (VALUE_LVAL (value) == lval_memory)
1216 fprintf_unfiltered (gdb_stdlog, " address=%s",
1218 value_address (value)));
1220 fprintf_unfiltered (gdb_stdlog, " computed");
1222 if (value_lazy (value))
1223 fprintf_unfiltered (gdb_stdlog, " lazy");
1227 const gdb_byte *buf = value_contents (value);
1229 fprintf_unfiltered (gdb_stdlog, " bytes=");
1230 fprintf_unfiltered (gdb_stdlog, "[");
1231 for (i = 0; i < register_size (gdbarch, regnum); i++)
1232 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
1233 fprintf_unfiltered (gdb_stdlog, "]");
1237 fprintf_unfiltered (gdb_stdlog, " }\n");
1244 get_frame_register_value (struct frame_info *frame, int regnum)
1246 return frame_unwind_register_value (frame->next, regnum);
1250 frame_unwind_register_signed (struct frame_info *frame, int regnum)
1252 struct gdbarch *gdbarch = frame_unwind_arch (frame);
1253 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1254 int size = register_size (gdbarch, regnum);
1255 gdb_byte buf[MAX_REGISTER_SIZE];
1257 frame_unwind_register (frame, regnum, buf);
1258 return extract_signed_integer (buf, size, byte_order);
1262 get_frame_register_signed (struct frame_info *frame, int regnum)
1264 return frame_unwind_register_signed (frame->next, regnum);
1268 frame_unwind_register_unsigned (struct frame_info *frame, int regnum)
1270 struct gdbarch *gdbarch = frame_unwind_arch (frame);
1271 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1272 int size = register_size (gdbarch, regnum);
1273 gdb_byte buf[MAX_REGISTER_SIZE];
1275 frame_unwind_register (frame, regnum, buf);
1276 return extract_unsigned_integer (buf, size, byte_order);
1280 get_frame_register_unsigned (struct frame_info *frame, int regnum)
1282 return frame_unwind_register_unsigned (frame->next, regnum);
1286 read_frame_register_unsigned (struct frame_info *frame, int regnum,
1289 struct value *regval = get_frame_register_value (frame, regnum);
1291 if (!value_optimized_out (regval)
1292 && value_entirely_available (regval))
1294 struct gdbarch *gdbarch = get_frame_arch (frame);
1295 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1296 int size = register_size (gdbarch, VALUE_REGNUM (regval));
1298 *val = extract_unsigned_integer (value_contents (regval), size, byte_order);
1306 put_frame_register (struct frame_info *frame, int regnum,
1307 const gdb_byte *buf)
1309 struct gdbarch *gdbarch = get_frame_arch (frame);
1313 enum lval_type lval;
1316 frame_register (frame, regnum, &optim, &unavail,
1317 &lval, &addr, &realnum, NULL);
1319 error (_("Attempt to assign to a register that was not saved."));
1324 write_memory (addr, buf, register_size (gdbarch, regnum));
1328 regcache_cooked_write (get_current_regcache (), realnum, buf);
1331 error (_("Attempt to assign to an unmodifiable value."));
1335 /* This function is deprecated. Use get_frame_register_value instead,
1336 which provides more accurate information.
1338 Find and return the value of REGNUM for the specified stack frame.
1339 The number of bytes copied is REGISTER_SIZE (REGNUM).
1341 Returns 0 if the register value could not be found. */
1344 deprecated_frame_register_read (struct frame_info *frame, int regnum,
1349 enum lval_type lval;
1353 frame_register (frame, regnum, &optimized, &unavailable,
1354 &lval, &addr, &realnum, myaddr);
1356 return !optimized && !unavailable;
1360 get_frame_register_bytes (struct frame_info *frame, int regnum,
1361 CORE_ADDR offset, int len, gdb_byte *myaddr,
1362 int *optimizedp, int *unavailablep)
1364 struct gdbarch *gdbarch = get_frame_arch (frame);
1369 /* Skip registers wholly inside of OFFSET. */
1370 while (offset >= register_size (gdbarch, regnum))
1372 offset -= register_size (gdbarch, regnum);
1376 /* Ensure that we will not read beyond the end of the register file.
1377 This can only ever happen if the debug information is bad. */
1379 numregs = gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
1380 for (i = regnum; i < numregs; i++)
1382 int thissize = register_size (gdbarch, i);
1385 break; /* This register is not available on this architecture. */
1386 maxsize += thissize;
1389 error (_("Bad debug information detected: "
1390 "Attempt to read %d bytes from registers."), len);
1392 /* Copy the data. */
1395 int curr_len = register_size (gdbarch, regnum) - offset;
1400 if (curr_len == register_size (gdbarch, regnum))
1402 enum lval_type lval;
1406 frame_register (frame, regnum, optimizedp, unavailablep,
1407 &lval, &addr, &realnum, myaddr);
1408 if (*optimizedp || *unavailablep)
1413 gdb_byte buf[MAX_REGISTER_SIZE];
1414 enum lval_type lval;
1418 frame_register (frame, regnum, optimizedp, unavailablep,
1419 &lval, &addr, &realnum, buf);
1420 if (*optimizedp || *unavailablep)
1422 memcpy (myaddr, buf + offset, curr_len);
1437 put_frame_register_bytes (struct frame_info *frame, int regnum,
1438 CORE_ADDR offset, int len, const gdb_byte *myaddr)
1440 struct gdbarch *gdbarch = get_frame_arch (frame);
1442 /* Skip registers wholly inside of OFFSET. */
1443 while (offset >= register_size (gdbarch, regnum))
1445 offset -= register_size (gdbarch, regnum);
1449 /* Copy the data. */
1452 int curr_len = register_size (gdbarch, regnum) - offset;
1457 if (curr_len == register_size (gdbarch, regnum))
1459 put_frame_register (frame, regnum, myaddr);
1463 gdb_byte buf[MAX_REGISTER_SIZE];
1465 deprecated_frame_register_read (frame, regnum, buf);
1466 memcpy (buf + offset, myaddr, curr_len);
1467 put_frame_register (frame, regnum, buf);
1477 /* Create a sentinel frame. */
1479 static struct frame_info *
1480 create_sentinel_frame (struct program_space *pspace, struct regcache *regcache)
1482 struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
1485 frame->pspace = pspace;
1486 frame->aspace = get_regcache_aspace (regcache);
1487 /* Explicitly initialize the sentinel frame's cache. Provide it
1488 with the underlying regcache. In the future additional
1489 information, such as the frame's thread will be added. */
1490 frame->prologue_cache = sentinel_frame_cache (regcache);
1491 /* For the moment there is only one sentinel frame implementation. */
1492 frame->unwind = &sentinel_frame_unwind;
1493 /* Link this frame back to itself. The frame is self referential
1494 (the unwound PC is the same as the pc), so make it so. */
1495 frame->next = frame;
1496 /* The sentinel frame has a special ID. */
1497 frame->this_id.p = 1;
1498 frame->this_id.value = sentinel_frame_id;
1501 fprintf_unfiltered (gdb_stdlog, "{ create_sentinel_frame (...) -> ");
1502 fprint_frame (gdb_stdlog, frame);
1503 fprintf_unfiltered (gdb_stdlog, " }\n");
1508 /* Cache for frame addresses already read by gdb. Valid only while
1509 inferior is stopped. Control variables for the frame cache should
1510 be local to this module. */
1512 static struct obstack frame_cache_obstack;
1515 frame_obstack_zalloc (unsigned long size)
1517 void *data = obstack_alloc (&frame_cache_obstack, size);
1519 memset (data, 0, size);
1523 static struct frame_info *get_prev_frame_always_1 (struct frame_info *this_frame);
1526 get_current_frame (void)
1528 struct frame_info *current_frame;
1530 /* First check, and report, the lack of registers. Having GDB
1531 report "No stack!" or "No memory" when the target doesn't even
1532 have registers is very confusing. Besides, "printcmd.exp"
1533 explicitly checks that ``print $pc'' with no registers prints "No
1535 if (!target_has_registers)
1536 error (_("No registers."));
1537 if (!target_has_stack)
1538 error (_("No stack."));
1539 if (!target_has_memory)
1540 error (_("No memory."));
1541 /* Traceframes are effectively a substitute for the live inferior. */
1542 if (get_traceframe_number () < 0)
1543 validate_registers_access ();
1545 if (sentinel_frame == NULL)
1547 create_sentinel_frame (current_program_space, get_current_regcache ());
1549 /* Set the current frame before computing the frame id, to avoid
1550 recursion inside compute_frame_id, in case the frame's
1551 unwinder decides to do a symbol lookup (which depends on the
1552 selected frame's block).
1554 This call must always succeed. In particular, nothing inside
1555 get_prev_frame_always_1 should try to unwind from the
1556 sentinel frame, because that could fail/throw, and we always
1557 want to leave with the current frame created and linked in --
1558 we should never end up with the sentinel frame as outermost
1560 current_frame = get_prev_frame_always_1 (sentinel_frame);
1561 gdb_assert (current_frame != NULL);
1563 return current_frame;
1566 /* The "selected" stack frame is used by default for local and arg
1567 access. May be zero, for no selected frame. */
1569 static struct frame_info *selected_frame;
1572 has_stack_frames (void)
1574 if (!target_has_registers || !target_has_stack || !target_has_memory)
1577 /* Traceframes are effectively a substitute for the live inferior. */
1578 if (get_traceframe_number () < 0)
1580 /* No current inferior, no frame. */
1581 if (ptid_equal (inferior_ptid, null_ptid))
1584 /* Don't try to read from a dead thread. */
1585 if (is_exited (inferior_ptid))
1588 /* ... or from a spinning thread. */
1589 if (is_executing (inferior_ptid))
1596 /* Return the selected frame. Always non-NULL (unless there isn't an
1597 inferior sufficient for creating a frame) in which case an error is
1601 get_selected_frame (const char *message)
1603 if (selected_frame == NULL)
1605 if (message != NULL && !has_stack_frames ())
1606 error (("%s"), message);
1607 /* Hey! Don't trust this. It should really be re-finding the
1608 last selected frame of the currently selected thread. This,
1609 though, is better than nothing. */
1610 select_frame (get_current_frame ());
1612 /* There is always a frame. */
1613 gdb_assert (selected_frame != NULL);
1614 return selected_frame;
1617 /* If there is a selected frame, return it. Otherwise, return NULL. */
1620 get_selected_frame_if_set (void)
1622 return selected_frame;
1625 /* This is a variant of get_selected_frame() which can be called when
1626 the inferior does not have a frame; in that case it will return
1627 NULL instead of calling error(). */
1630 deprecated_safe_get_selected_frame (void)
1632 if (!has_stack_frames ())
1634 return get_selected_frame (NULL);
1637 /* Select frame FI (or NULL - to invalidate the current frame). */
1640 select_frame (struct frame_info *fi)
1642 selected_frame = fi;
1643 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
1644 frame is being invalidated. */
1646 /* FIXME: kseitz/2002-08-28: It would be nice to call
1647 selected_frame_level_changed_event() right here, but due to limitations
1648 in the current interfaces, we would end up flooding UIs with events
1649 because select_frame() is used extensively internally.
1651 Once we have frame-parameterized frame (and frame-related) commands,
1652 the event notification can be moved here, since this function will only
1653 be called when the user's selected frame is being changed. */
1655 /* Ensure that symbols for this frame are read in. Also, determine the
1656 source language of this frame, and switch to it if desired. */
1661 /* We retrieve the frame's symtab by using the frame PC.
1662 However we cannot use the frame PC as-is, because it usually
1663 points to the instruction following the "call", which is
1664 sometimes the first instruction of another function. So we
1665 rely on get_frame_address_in_block() which provides us with a
1666 PC which is guaranteed to be inside the frame's code
1668 if (get_frame_address_in_block_if_available (fi, &pc))
1670 struct compunit_symtab *cust = find_pc_compunit_symtab (pc);
1673 && compunit_language (cust) != current_language->la_language
1674 && compunit_language (cust) != language_unknown
1675 && language_mode == language_mode_auto)
1676 set_language (compunit_language (cust));
1681 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
1682 Always returns a non-NULL value. */
1685 create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
1687 struct frame_info *fi;
1691 fprintf_unfiltered (gdb_stdlog,
1692 "{ create_new_frame (addr=%s, pc=%s) ",
1693 hex_string (addr), hex_string (pc));
1696 fi = FRAME_OBSTACK_ZALLOC (struct frame_info);
1698 fi->next = create_sentinel_frame (current_program_space,
1699 get_current_regcache ());
1701 /* Set/update this frame's cached PC value, found in the next frame.
1702 Do this before looking for this frame's unwinder. A sniffer is
1703 very likely to read this, and the corresponding unwinder is
1704 entitled to rely that the PC doesn't magically change. */
1705 fi->next->prev_pc.value = pc;
1706 fi->next->prev_pc.status = CC_VALUE;
1708 /* We currently assume that frame chain's can't cross spaces. */
1709 fi->pspace = fi->next->pspace;
1710 fi->aspace = fi->next->aspace;
1712 /* Select/initialize both the unwind function and the frame's type
1714 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
1717 fi->this_id.value = frame_id_build (addr, pc);
1721 fprintf_unfiltered (gdb_stdlog, "-> ");
1722 fprint_frame (gdb_stdlog, fi);
1723 fprintf_unfiltered (gdb_stdlog, " }\n");
1729 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
1730 innermost frame). Be careful to not fall off the bottom of the
1731 frame chain and onto the sentinel frame. */
1734 get_next_frame (struct frame_info *this_frame)
1736 if (this_frame->level > 0)
1737 return this_frame->next;
1742 /* Return the frame that THIS_FRAME calls. If THIS_FRAME is the
1743 innermost (i.e. current) frame, return the sentinel frame. Thus,
1744 unlike get_next_frame(), NULL will never be returned. */
1747 get_next_frame_sentinel_okay (struct frame_info *this_frame)
1749 gdb_assert (this_frame != NULL);
1751 /* Note that, due to the manner in which the sentinel frame is
1752 constructed, this_frame->next still works even when this_frame
1753 is the sentinel frame. But we disallow it here anyway because
1754 calling get_next_frame_sentinel_okay() on the sentinel frame
1755 is likely a coding error. */
1756 gdb_assert (this_frame != sentinel_frame);
1758 return this_frame->next;
1761 /* Observer for the target_changed event. */
1764 frame_observer_target_changed (struct target_ops *target)
1766 reinit_frame_cache ();
1769 /* Flush the entire frame cache. */
1772 reinit_frame_cache (void)
1774 struct frame_info *fi;
1776 /* Tear down all frame caches. */
1777 for (fi = sentinel_frame; fi != NULL; fi = fi->prev)
1779 if (fi->prologue_cache && fi->unwind->dealloc_cache)
1780 fi->unwind->dealloc_cache (fi, fi->prologue_cache);
1781 if (fi->base_cache && fi->base->unwind->dealloc_cache)
1782 fi->base->unwind->dealloc_cache (fi, fi->base_cache);
1785 /* Since we can't really be sure what the first object allocated was. */
1786 obstack_free (&frame_cache_obstack, 0);
1787 obstack_init (&frame_cache_obstack);
1789 if (sentinel_frame != NULL)
1790 annotate_frames_invalid ();
1792 sentinel_frame = NULL; /* Invalidate cache */
1793 select_frame (NULL);
1794 frame_stash_invalidate ();
1796 fprintf_unfiltered (gdb_stdlog, "{ reinit_frame_cache () }\n");
1799 /* Find where a register is saved (in memory or another register).
1800 The result of frame_register_unwind is just where it is saved
1801 relative to this particular frame. */
1804 frame_register_unwind_location (struct frame_info *this_frame, int regnum,
1805 int *optimizedp, enum lval_type *lvalp,
1806 CORE_ADDR *addrp, int *realnump)
1808 gdb_assert (this_frame == NULL || this_frame->level >= 0);
1810 while (this_frame != NULL)
1814 frame_register_unwind (this_frame, regnum, optimizedp, &unavailable,
1815 lvalp, addrp, realnump, NULL);
1820 if (*lvalp != lval_register)
1824 this_frame = get_next_frame (this_frame);
1828 /* Called during frame unwinding to remove a previous frame pointer from a
1829 frame passed in ARG. */
1832 remove_prev_frame (void *arg)
1834 struct frame_info *this_frame, *prev_frame;
1836 this_frame = (struct frame_info *) arg;
1837 prev_frame = this_frame->prev;
1838 gdb_assert (prev_frame != NULL);
1840 prev_frame->next = NULL;
1841 this_frame->prev = NULL;
1844 /* Get the previous raw frame, and check that it is not identical to
1845 same other frame frame already in the chain. If it is, there is
1846 most likely a stack cycle, so we discard it, and mark THIS_FRAME as
1847 outermost, with UNWIND_SAME_ID stop reason. Unlike the other
1848 validity tests, that compare THIS_FRAME and the next frame, we do
1849 this right after creating the previous frame, to avoid ever ending
1850 up with two frames with the same id in the frame chain. */
1852 static struct frame_info *
1853 get_prev_frame_if_no_cycle (struct frame_info *this_frame)
1855 struct frame_info *prev_frame;
1856 struct cleanup *prev_frame_cleanup;
1858 prev_frame = get_prev_frame_raw (this_frame);
1860 /* Don't compute the frame id of the current frame yet. Unwinding
1861 the sentinel frame can fail (e.g., if the thread is gone and we
1862 can't thus read its registers). If we let the cycle detection
1863 code below try to compute a frame ID, then an error thrown from
1864 within the frame ID computation would result in the sentinel
1865 frame as outermost frame, which is bogus. Instead, we'll compute
1866 the current frame's ID lazily in get_frame_id. Note that there's
1867 no point in doing cycle detection when there's only one frame, so
1868 nothing is lost here. */
1869 if (prev_frame->level == 0)
1872 /* The cleanup will remove the previous frame that get_prev_frame_raw
1873 linked onto THIS_FRAME. */
1874 prev_frame_cleanup = make_cleanup (remove_prev_frame, this_frame);
1876 compute_frame_id (prev_frame);
1877 if (!frame_stash_add (prev_frame))
1879 /* Another frame with the same id was already in the stash. We just
1880 detected a cycle. */
1883 fprintf_unfiltered (gdb_stdlog, "-> ");
1884 fprint_frame (gdb_stdlog, NULL);
1885 fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n");
1887 this_frame->stop_reason = UNWIND_SAME_ID;
1889 prev_frame->next = NULL;
1890 this_frame->prev = NULL;
1894 discard_cleanups (prev_frame_cleanup);
1898 /* Helper function for get_prev_frame_always, this is called inside a
1899 TRY_CATCH block. Return the frame that called THIS_FRAME or NULL if
1900 there is no such frame. This may throw an exception. */
1902 static struct frame_info *
1903 get_prev_frame_always_1 (struct frame_info *this_frame)
1905 struct gdbarch *gdbarch;
1907 gdb_assert (this_frame != NULL);
1908 gdbarch = get_frame_arch (this_frame);
1912 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame_always (this_frame=");
1913 if (this_frame != NULL)
1914 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
1916 fprintf_unfiltered (gdb_stdlog, "<NULL>");
1917 fprintf_unfiltered (gdb_stdlog, ") ");
1920 /* Only try to do the unwind once. */
1921 if (this_frame->prev_p)
1925 fprintf_unfiltered (gdb_stdlog, "-> ");
1926 fprint_frame (gdb_stdlog, this_frame->prev);
1927 fprintf_unfiltered (gdb_stdlog, " // cached \n");
1929 return this_frame->prev;
1932 /* If the frame unwinder hasn't been selected yet, we must do so
1933 before setting prev_p; otherwise the check for misbehaved
1934 sniffers will think that this frame's sniffer tried to unwind
1935 further (see frame_cleanup_after_sniffer). */
1936 if (this_frame->unwind == NULL)
1937 frame_unwind_find_by_frame (this_frame, &this_frame->prologue_cache);
1939 this_frame->prev_p = 1;
1940 this_frame->stop_reason = UNWIND_NO_REASON;
1942 /* If we are unwinding from an inline frame, all of the below tests
1943 were already performed when we unwound from the next non-inline
1944 frame. We must skip them, since we can not get THIS_FRAME's ID
1945 until we have unwound all the way down to the previous non-inline
1947 if (get_frame_type (this_frame) == INLINE_FRAME)
1948 return get_prev_frame_if_no_cycle (this_frame);
1950 /* Check that this frame is unwindable. If it isn't, don't try to
1951 unwind to the prev frame. */
1952 this_frame->stop_reason
1953 = this_frame->unwind->stop_reason (this_frame,
1954 &this_frame->prologue_cache);
1956 if (this_frame->stop_reason != UNWIND_NO_REASON)
1960 enum unwind_stop_reason reason = this_frame->stop_reason;
1962 fprintf_unfiltered (gdb_stdlog, "-> ");
1963 fprint_frame (gdb_stdlog, NULL);
1964 fprintf_unfiltered (gdb_stdlog, " // %s }\n",
1965 frame_stop_reason_symbol_string (reason));
1970 /* Check that this frame's ID isn't inner to (younger, below, next)
1971 the next frame. This happens when a frame unwind goes backwards.
1972 This check is valid only if this frame and the next frame are NORMAL.
1973 See the comment at frame_id_inner for details. */
1974 if (get_frame_type (this_frame) == NORMAL_FRAME
1975 && this_frame->next->unwind->type == NORMAL_FRAME
1976 && frame_id_inner (get_frame_arch (this_frame->next),
1977 get_frame_id (this_frame),
1978 get_frame_id (this_frame->next)))
1980 CORE_ADDR this_pc_in_block;
1981 struct minimal_symbol *morestack_msym;
1982 const char *morestack_name = NULL;
1984 /* gcc -fsplit-stack __morestack can continue the stack anywhere. */
1985 this_pc_in_block = get_frame_address_in_block (this_frame);
1986 morestack_msym = lookup_minimal_symbol_by_pc (this_pc_in_block).minsym;
1988 morestack_name = MSYMBOL_LINKAGE_NAME (morestack_msym);
1989 if (!morestack_name || strcmp (morestack_name, "__morestack") != 0)
1993 fprintf_unfiltered (gdb_stdlog, "-> ");
1994 fprint_frame (gdb_stdlog, NULL);
1995 fprintf_unfiltered (gdb_stdlog,
1996 " // this frame ID is inner }\n");
1998 this_frame->stop_reason = UNWIND_INNER_ID;
2003 /* Check that this and the next frame do not unwind the PC register
2004 to the same memory location. If they do, then even though they
2005 have different frame IDs, the new frame will be bogus; two
2006 functions can't share a register save slot for the PC. This can
2007 happen when the prologue analyzer finds a stack adjustment, but
2010 This check does assume that the "PC register" is roughly a
2011 traditional PC, even if the gdbarch_unwind_pc method adjusts
2012 it (we do not rely on the value, only on the unwound PC being
2013 dependent on this value). A potential improvement would be
2014 to have the frame prev_pc method and the gdbarch unwind_pc
2015 method set the same lval and location information as
2016 frame_register_unwind. */
2017 if (this_frame->level > 0
2018 && gdbarch_pc_regnum (gdbarch) >= 0
2019 && get_frame_type (this_frame) == NORMAL_FRAME
2020 && (get_frame_type (this_frame->next) == NORMAL_FRAME
2021 || get_frame_type (this_frame->next) == INLINE_FRAME))
2023 int optimized, realnum, nrealnum;
2024 enum lval_type lval, nlval;
2025 CORE_ADDR addr, naddr;
2027 frame_register_unwind_location (this_frame,
2028 gdbarch_pc_regnum (gdbarch),
2029 &optimized, &lval, &addr, &realnum);
2030 frame_register_unwind_location (get_next_frame (this_frame),
2031 gdbarch_pc_regnum (gdbarch),
2032 &optimized, &nlval, &naddr, &nrealnum);
2034 if ((lval == lval_memory && lval == nlval && addr == naddr)
2035 || (lval == lval_register && lval == nlval && realnum == nrealnum))
2039 fprintf_unfiltered (gdb_stdlog, "-> ");
2040 fprint_frame (gdb_stdlog, NULL);
2041 fprintf_unfiltered (gdb_stdlog, " // no saved PC }\n");
2044 this_frame->stop_reason = UNWIND_NO_SAVED_PC;
2045 this_frame->prev = NULL;
2050 return get_prev_frame_if_no_cycle (this_frame);
2053 /* Return a "struct frame_info" corresponding to the frame that called
2054 THIS_FRAME. Returns NULL if there is no such frame.
2056 Unlike get_prev_frame, this function always tries to unwind the
2060 get_prev_frame_always (struct frame_info *this_frame)
2062 struct frame_info *prev_frame = NULL;
2066 prev_frame = get_prev_frame_always_1 (this_frame);
2068 CATCH (ex, RETURN_MASK_ERROR)
2070 if (ex.error == MEMORY_ERROR)
2072 this_frame->stop_reason = UNWIND_MEMORY_ERROR;
2073 if (ex.message != NULL)
2078 /* The error needs to live as long as the frame does.
2079 Allocate using stack local STOP_STRING then assign the
2080 pointer to the frame, this allows the STOP_STRING on the
2081 frame to be of type 'const char *'. */
2082 size = strlen (ex.message) + 1;
2083 stop_string = (char *) frame_obstack_zalloc (size);
2084 memcpy (stop_string, ex.message, size);
2085 this_frame->stop_string = stop_string;
2090 throw_exception (ex);
2097 /* Construct a new "struct frame_info" and link it previous to
2100 static struct frame_info *
2101 get_prev_frame_raw (struct frame_info *this_frame)
2103 struct frame_info *prev_frame;
2105 /* Allocate the new frame but do not wire it in to the frame chain.
2106 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
2107 frame->next to pull some fancy tricks (of course such code is, by
2108 definition, recursive). Try to prevent it.
2110 There is no reason to worry about memory leaks, should the
2111 remainder of the function fail. The allocated memory will be
2112 quickly reclaimed when the frame cache is flushed, and the `we've
2113 been here before' check above will stop repeated memory
2114 allocation calls. */
2115 prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
2116 prev_frame->level = this_frame->level + 1;
2118 /* For now, assume we don't have frame chains crossing address
2120 prev_frame->pspace = this_frame->pspace;
2121 prev_frame->aspace = this_frame->aspace;
2123 /* Don't yet compute ->unwind (and hence ->type). It is computed
2124 on-demand in get_frame_type, frame_register_unwind, and
2127 /* Don't yet compute the frame's ID. It is computed on-demand by
2130 /* The unwound frame ID is validate at the start of this function,
2131 as part of the logic to decide if that frame should be further
2132 unwound, and not here while the prev frame is being created.
2133 Doing this makes it possible for the user to examine a frame that
2134 has an invalid frame ID.
2136 Some very old VAX code noted: [...] For the sake of argument,
2137 suppose that the stack is somewhat trashed (which is one reason
2138 that "info frame" exists). So, return 0 (indicating we don't
2139 know the address of the arglist) if we don't know what frame this
2143 this_frame->prev = prev_frame;
2144 prev_frame->next = this_frame;
2148 fprintf_unfiltered (gdb_stdlog, "-> ");
2149 fprint_frame (gdb_stdlog, prev_frame);
2150 fprintf_unfiltered (gdb_stdlog, " }\n");
2156 /* Debug routine to print a NULL frame being returned. */
2159 frame_debug_got_null_frame (struct frame_info *this_frame,
2164 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame (this_frame=");
2165 if (this_frame != NULL)
2166 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
2168 fprintf_unfiltered (gdb_stdlog, "<NULL>");
2169 fprintf_unfiltered (gdb_stdlog, ") -> // %s}\n", reason);
2173 /* Is this (non-sentinel) frame in the "main"() function? */
2176 inside_main_func (struct frame_info *this_frame)
2178 struct bound_minimal_symbol msymbol;
2181 if (symfile_objfile == 0)
2183 msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
2184 if (msymbol.minsym == NULL)
2186 /* Make certain that the code, and not descriptor, address is
2188 maddr = gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame),
2189 BMSYMBOL_VALUE_ADDRESS (msymbol),
2191 return maddr == get_frame_func (this_frame);
2194 /* Test whether THIS_FRAME is inside the process entry point function. */
2197 inside_entry_func (struct frame_info *this_frame)
2199 CORE_ADDR entry_point;
2201 if (!entry_point_address_query (&entry_point))
2204 return get_frame_func (this_frame) == entry_point;
2207 /* Return a structure containing various interesting information about
2208 the frame that called THIS_FRAME. Returns NULL if there is entier
2209 no such frame or the frame fails any of a set of target-independent
2210 condition that should terminate the frame chain (e.g., as unwinding
2213 This function should not contain target-dependent tests, such as
2214 checking whether the program-counter is zero. */
2217 get_prev_frame (struct frame_info *this_frame)
2222 /* There is always a frame. If this assertion fails, suspect that
2223 something should be calling get_selected_frame() or
2224 get_current_frame(). */
2225 gdb_assert (this_frame != NULL);
2227 /* If this_frame is the current frame, then compute and stash
2228 its frame id prior to fetching and computing the frame id of the
2229 previous frame. Otherwise, the cycle detection code in
2230 get_prev_frame_if_no_cycle() will not work correctly. When
2231 get_frame_id() is called later on, an assertion error will
2232 be triggered in the event of a cycle between the current
2233 frame and its previous frame. */
2234 if (this_frame->level == 0)
2235 get_frame_id (this_frame);
2237 frame_pc_p = get_frame_pc_if_available (this_frame, &frame_pc);
2239 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
2240 sense to stop unwinding at a dummy frame. One place where a dummy
2241 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
2242 pcsqh register (space register for the instruction at the head of the
2243 instruction queue) cannot be written directly; the only way to set it
2244 is to branch to code that is in the target space. In order to implement
2245 frame dummies on HPUX, the called function is made to jump back to where
2246 the inferior was when the user function was called. If gdb was inside
2247 the main function when we created the dummy frame, the dummy frame will
2248 point inside the main function. */
2249 if (this_frame->level >= 0
2250 && get_frame_type (this_frame) == NORMAL_FRAME
2251 && !backtrace_past_main
2253 && inside_main_func (this_frame))
2254 /* Don't unwind past main(). Note, this is done _before_ the
2255 frame has been marked as previously unwound. That way if the
2256 user later decides to enable unwinds past main(), that will
2257 automatically happen. */
2259 frame_debug_got_null_frame (this_frame, "inside main func");
2263 /* If the user's backtrace limit has been exceeded, stop. We must
2264 add two to the current level; one of those accounts for backtrace_limit
2265 being 1-based and the level being 0-based, and the other accounts for
2266 the level of the new frame instead of the level of the current
2268 if (this_frame->level + 2 > backtrace_limit)
2270 frame_debug_got_null_frame (this_frame, "backtrace limit exceeded");
2274 /* If we're already inside the entry function for the main objfile,
2275 then it isn't valid. Don't apply this test to a dummy frame -
2276 dummy frame PCs typically land in the entry func. Don't apply
2277 this test to the sentinel frame. Sentinel frames should always
2278 be allowed to unwind. */
2279 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
2280 wasn't checking for "main" in the minimal symbols. With that
2281 fixed asm-source tests now stop in "main" instead of halting the
2282 backtrace in weird and wonderful ways somewhere inside the entry
2283 file. Suspect that tests for inside the entry file/func were
2284 added to work around that (now fixed) case. */
2285 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
2286 suggested having the inside_entry_func test use the
2287 inside_main_func() msymbol trick (along with entry_point_address()
2288 I guess) to determine the address range of the start function.
2289 That should provide a far better stopper than the current
2291 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
2292 applied tail-call optimizations to main so that a function called
2293 from main returns directly to the caller of main. Since we don't
2294 stop at main, we should at least stop at the entry point of the
2296 if (this_frame->level >= 0
2297 && get_frame_type (this_frame) == NORMAL_FRAME
2298 && !backtrace_past_entry
2300 && inside_entry_func (this_frame))
2302 frame_debug_got_null_frame (this_frame, "inside entry func");
2306 /* Assume that the only way to get a zero PC is through something
2307 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
2308 will never unwind a zero PC. */
2309 if (this_frame->level > 0
2310 && (get_frame_type (this_frame) == NORMAL_FRAME
2311 || get_frame_type (this_frame) == INLINE_FRAME)
2312 && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME
2313 && frame_pc_p && frame_pc == 0)
2315 frame_debug_got_null_frame (this_frame, "zero PC");
2319 return get_prev_frame_always (this_frame);
2323 get_prev_frame_id_by_id (struct frame_id id)
2325 struct frame_id prev_id;
2326 struct frame_info *frame;
2328 frame = frame_find_by_id (id);
2331 prev_id = get_frame_id (get_prev_frame (frame));
2333 prev_id = null_frame_id;
2339 get_frame_pc (struct frame_info *frame)
2341 gdb_assert (frame->next != NULL);
2342 return frame_unwind_pc (frame->next);
2346 get_frame_pc_if_available (struct frame_info *frame, CORE_ADDR *pc)
2349 gdb_assert (frame->next != NULL);
2353 *pc = frame_unwind_pc (frame->next);
2355 CATCH (ex, RETURN_MASK_ERROR)
2357 if (ex.error == NOT_AVAILABLE_ERROR)
2360 throw_exception (ex);
2367 /* Return an address that falls within THIS_FRAME's code block. */
2370 get_frame_address_in_block (struct frame_info *this_frame)
2372 /* A draft address. */
2373 CORE_ADDR pc = get_frame_pc (this_frame);
2375 struct frame_info *next_frame = this_frame->next;
2377 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
2378 Normally the resume address is inside the body of the function
2379 associated with THIS_FRAME, but there is a special case: when
2380 calling a function which the compiler knows will never return
2381 (for instance abort), the call may be the very last instruction
2382 in the calling function. The resume address will point after the
2383 call and may be at the beginning of a different function
2386 If THIS_FRAME is a signal frame or dummy frame, then we should
2387 not adjust the unwound PC. For a dummy frame, GDB pushed the
2388 resume address manually onto the stack. For a signal frame, the
2389 OS may have pushed the resume address manually and invoked the
2390 handler (e.g. GNU/Linux), or invoked the trampoline which called
2391 the signal handler - but in either case the signal handler is
2392 expected to return to the trampoline. So in both of these
2393 cases we know that the resume address is executable and
2394 related. So we only need to adjust the PC if THIS_FRAME
2395 is a normal function.
2397 If the program has been interrupted while THIS_FRAME is current,
2398 then clearly the resume address is inside the associated
2399 function. There are three kinds of interruption: debugger stop
2400 (next frame will be SENTINEL_FRAME), operating system
2401 signal or exception (next frame will be SIGTRAMP_FRAME),
2402 or debugger-induced function call (next frame will be
2403 DUMMY_FRAME). So we only need to adjust the PC if
2404 NEXT_FRAME is a normal function.
2406 We check the type of NEXT_FRAME first, since it is already
2407 known; frame type is determined by the unwinder, and since
2408 we have THIS_FRAME we've already selected an unwinder for
2411 If the next frame is inlined, we need to keep going until we find
2412 the real function - for instance, if a signal handler is invoked
2413 while in an inlined function, then the code address of the
2414 "calling" normal function should not be adjusted either. */
2416 while (get_frame_type (next_frame) == INLINE_FRAME)
2417 next_frame = next_frame->next;
2419 if ((get_frame_type (next_frame) == NORMAL_FRAME
2420 || get_frame_type (next_frame) == TAILCALL_FRAME)
2421 && (get_frame_type (this_frame) == NORMAL_FRAME
2422 || get_frame_type (this_frame) == TAILCALL_FRAME
2423 || get_frame_type (this_frame) == INLINE_FRAME))
2430 get_frame_address_in_block_if_available (struct frame_info *this_frame,
2436 *pc = get_frame_address_in_block (this_frame);
2438 CATCH (ex, RETURN_MASK_ERROR)
2440 if (ex.error == NOT_AVAILABLE_ERROR)
2442 throw_exception (ex);
2450 find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal)
2452 struct frame_info *next_frame;
2456 /* If the next frame represents an inlined function call, this frame's
2457 sal is the "call site" of that inlined function, which can not
2458 be inferred from get_frame_pc. */
2459 next_frame = get_next_frame (frame);
2460 if (frame_inlined_callees (frame) > 0)
2465 sym = get_frame_function (next_frame);
2467 sym = inline_skipped_symbol (inferior_ptid);
2469 /* If frame is inline, it certainly has symbols. */
2472 if (SYMBOL_LINE (sym) != 0)
2474 sal->symtab = symbol_symtab (sym);
2475 sal->line = SYMBOL_LINE (sym);
2478 /* If the symbol does not have a location, we don't know where
2479 the call site is. Do not pretend to. This is jarring, but
2480 we can't do much better. */
2481 sal->pc = get_frame_pc (frame);
2483 sal->pspace = get_frame_program_space (frame);
2488 /* If FRAME is not the innermost frame, that normally means that
2489 FRAME->pc points at the return instruction (which is *after* the
2490 call instruction), and we want to get the line containing the
2491 call (because the call is where the user thinks the program is).
2492 However, if the next frame is either a SIGTRAMP_FRAME or a
2493 DUMMY_FRAME, then the next frame will contain a saved interrupt
2494 PC and such a PC indicates the current (rather than next)
2495 instruction/line, consequently, for such cases, want to get the
2496 line containing fi->pc. */
2497 if (!get_frame_pc_if_available (frame, &pc))
2503 notcurrent = (pc != get_frame_address_in_block (frame));
2504 (*sal) = find_pc_line (pc, notcurrent);
2507 /* Per "frame.h", return the ``address'' of the frame. Code should
2508 really be using get_frame_id(). */
2510 get_frame_base (struct frame_info *fi)
2512 return get_frame_id (fi).stack_addr;
2515 /* High-level offsets into the frame. Used by the debug info. */
2518 get_frame_base_address (struct frame_info *fi)
2520 if (get_frame_type (fi) != NORMAL_FRAME)
2522 if (fi->base == NULL)
2523 fi->base = frame_base_find_by_frame (fi);
2524 /* Sneaky: If the low-level unwind and high-level base code share a
2525 common unwinder, let them share the prologue cache. */
2526 if (fi->base->unwind == fi->unwind)
2527 return fi->base->this_base (fi, &fi->prologue_cache);
2528 return fi->base->this_base (fi, &fi->base_cache);
2532 get_frame_locals_address (struct frame_info *fi)
2534 if (get_frame_type (fi) != NORMAL_FRAME)
2536 /* If there isn't a frame address method, find it. */
2537 if (fi->base == NULL)
2538 fi->base = frame_base_find_by_frame (fi);
2539 /* Sneaky: If the low-level unwind and high-level base code share a
2540 common unwinder, let them share the prologue cache. */
2541 if (fi->base->unwind == fi->unwind)
2542 return fi->base->this_locals (fi, &fi->prologue_cache);
2543 return fi->base->this_locals (fi, &fi->base_cache);
2547 get_frame_args_address (struct frame_info *fi)
2549 if (get_frame_type (fi) != NORMAL_FRAME)
2551 /* If there isn't a frame address method, find it. */
2552 if (fi->base == NULL)
2553 fi->base = frame_base_find_by_frame (fi);
2554 /* Sneaky: If the low-level unwind and high-level base code share a
2555 common unwinder, let them share the prologue cache. */
2556 if (fi->base->unwind == fi->unwind)
2557 return fi->base->this_args (fi, &fi->prologue_cache);
2558 return fi->base->this_args (fi, &fi->base_cache);
2561 /* Return true if the frame unwinder for frame FI is UNWINDER; false
2565 frame_unwinder_is (struct frame_info *fi, const struct frame_unwind *unwinder)
2567 if (fi->unwind == NULL)
2568 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
2569 return fi->unwind == unwinder;
2572 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
2573 or -1 for a NULL frame. */
2576 frame_relative_level (struct frame_info *fi)
2585 get_frame_type (struct frame_info *frame)
2587 if (frame->unwind == NULL)
2588 /* Initialize the frame's unwinder because that's what
2589 provides the frame's type. */
2590 frame_unwind_find_by_frame (frame, &frame->prologue_cache);
2591 return frame->unwind->type;
2594 struct program_space *
2595 get_frame_program_space (struct frame_info *frame)
2597 return frame->pspace;
2600 struct program_space *
2601 frame_unwind_program_space (struct frame_info *this_frame)
2603 gdb_assert (this_frame);
2605 /* This is really a placeholder to keep the API consistent --- we
2606 assume for now that we don't have frame chains crossing
2608 return this_frame->pspace;
2611 struct address_space *
2612 get_frame_address_space (struct frame_info *frame)
2614 return frame->aspace;
2617 /* Memory access methods. */
2620 get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr,
2621 gdb_byte *buf, int len)
2623 read_memory (addr, buf, len);
2627 get_frame_memory_signed (struct frame_info *this_frame, CORE_ADDR addr,
2630 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2631 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2633 return read_memory_integer (addr, len, byte_order);
2637 get_frame_memory_unsigned (struct frame_info *this_frame, CORE_ADDR addr,
2640 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2641 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2643 return read_memory_unsigned_integer (addr, len, byte_order);
2647 safe_frame_unwind_memory (struct frame_info *this_frame,
2648 CORE_ADDR addr, gdb_byte *buf, int len)
2650 /* NOTE: target_read_memory returns zero on success! */
2651 return !target_read_memory (addr, buf, len);
2654 /* Architecture methods. */
2657 get_frame_arch (struct frame_info *this_frame)
2659 return frame_unwind_arch (this_frame->next);
2663 frame_unwind_arch (struct frame_info *next_frame)
2665 if (!next_frame->prev_arch.p)
2667 struct gdbarch *arch;
2669 if (next_frame->unwind == NULL)
2670 frame_unwind_find_by_frame (next_frame, &next_frame->prologue_cache);
2672 if (next_frame->unwind->prev_arch != NULL)
2673 arch = next_frame->unwind->prev_arch (next_frame,
2674 &next_frame->prologue_cache);
2676 arch = get_frame_arch (next_frame);
2678 next_frame->prev_arch.arch = arch;
2679 next_frame->prev_arch.p = 1;
2681 fprintf_unfiltered (gdb_stdlog,
2682 "{ frame_unwind_arch (next_frame=%d) -> %s }\n",
2684 gdbarch_bfd_arch_info (arch)->printable_name);
2687 return next_frame->prev_arch.arch;
2691 frame_unwind_caller_arch (struct frame_info *next_frame)
2693 next_frame = skip_artificial_frames (next_frame);
2695 /* We must have a non-artificial frame. The caller is supposed to check
2696 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
2698 gdb_assert (next_frame != NULL);
2700 return frame_unwind_arch (next_frame);
2703 /* Gets the language of FRAME. */
2706 get_frame_language (struct frame_info *frame)
2711 gdb_assert (frame!= NULL);
2713 /* We determine the current frame language by looking up its
2714 associated symtab. To retrieve this symtab, we use the frame
2715 PC. However we cannot use the frame PC as is, because it
2716 usually points to the instruction following the "call", which
2717 is sometimes the first instruction of another function. So
2718 we rely on get_frame_address_in_block(), it provides us with
2719 a PC that is guaranteed to be inside the frame's code
2724 pc = get_frame_address_in_block (frame);
2727 CATCH (ex, RETURN_MASK_ERROR)
2729 if (ex.error != NOT_AVAILABLE_ERROR)
2730 throw_exception (ex);
2736 struct compunit_symtab *cust = find_pc_compunit_symtab (pc);
2739 return compunit_language (cust);
2742 return language_unknown;
2745 /* Stack pointer methods. */
2748 get_frame_sp (struct frame_info *this_frame)
2750 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2752 /* Normality - an architecture that provides a way of obtaining any
2753 frame inner-most address. */
2754 if (gdbarch_unwind_sp_p (gdbarch))
2755 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
2756 operate on THIS_FRAME now. */
2757 return gdbarch_unwind_sp (gdbarch, this_frame->next);
2758 /* Now things are really are grim. Hope that the value returned by
2759 the gdbarch_sp_regnum register is meaningful. */
2760 if (gdbarch_sp_regnum (gdbarch) >= 0)
2761 return get_frame_register_unsigned (this_frame,
2762 gdbarch_sp_regnum (gdbarch));
2763 internal_error (__FILE__, __LINE__, _("Missing unwind SP method"));
2766 /* Return the reason why we can't unwind past FRAME. */
2768 enum unwind_stop_reason
2769 get_frame_unwind_stop_reason (struct frame_info *frame)
2771 /* Fill-in STOP_REASON. */
2772 get_prev_frame_always (frame);
2773 gdb_assert (frame->prev_p);
2775 return frame->stop_reason;
2778 /* Return a string explaining REASON. */
2781 unwind_stop_reason_to_string (enum unwind_stop_reason reason)
2785 #define SET(name, description) \
2786 case name: return _(description);
2787 #include "unwind_stop_reasons.def"
2791 internal_error (__FILE__, __LINE__,
2792 "Invalid frame stop reason");
2797 frame_stop_reason_string (struct frame_info *fi)
2799 gdb_assert (fi->prev_p);
2800 gdb_assert (fi->prev == NULL);
2802 /* Return the specific string if we have one. */
2803 if (fi->stop_string != NULL)
2804 return fi->stop_string;
2806 /* Return the generic string if we have nothing better. */
2807 return unwind_stop_reason_to_string (fi->stop_reason);
2810 /* Return the enum symbol name of REASON as a string, to use in debug
2814 frame_stop_reason_symbol_string (enum unwind_stop_reason reason)
2818 #define SET(name, description) \
2819 case name: return #name;
2820 #include "unwind_stop_reasons.def"
2824 internal_error (__FILE__, __LINE__,
2825 "Invalid frame stop reason");
2829 /* Clean up after a failed (wrong unwinder) attempt to unwind past
2833 frame_cleanup_after_sniffer (void *arg)
2835 struct frame_info *frame = (struct frame_info *) arg;
2837 /* The sniffer should not allocate a prologue cache if it did not
2838 match this frame. */
2839 gdb_assert (frame->prologue_cache == NULL);
2841 /* No sniffer should extend the frame chain; sniff based on what is
2843 gdb_assert (!frame->prev_p);
2845 /* The sniffer should not check the frame's ID; that's circular. */
2846 gdb_assert (!frame->this_id.p);
2848 /* Clear cached fields dependent on the unwinder.
2850 The previous PC is independent of the unwinder, but the previous
2851 function is not (see get_frame_address_in_block). */
2852 frame->prev_func.p = 0;
2853 frame->prev_func.addr = 0;
2855 /* Discard the unwinder last, so that we can easily find it if an assertion
2856 in this function triggers. */
2857 frame->unwind = NULL;
2860 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
2861 Return a cleanup which should be called if unwinding fails, and
2862 discarded if it succeeds. */
2865 frame_prepare_for_sniffer (struct frame_info *frame,
2866 const struct frame_unwind *unwind)
2868 gdb_assert (frame->unwind == NULL);
2869 frame->unwind = unwind;
2870 return make_cleanup (frame_cleanup_after_sniffer, frame);
2873 extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */
2875 static struct cmd_list_element *set_backtrace_cmdlist;
2876 static struct cmd_list_element *show_backtrace_cmdlist;
2879 set_backtrace_cmd (char *args, int from_tty)
2881 help_list (set_backtrace_cmdlist, "set backtrace ", all_commands,
2886 show_backtrace_cmd (char *args, int from_tty)
2888 cmd_show_list (show_backtrace_cmdlist, from_tty, "");
2892 _initialize_frame (void)
2894 obstack_init (&frame_cache_obstack);
2896 frame_stash_create ();
2898 observer_attach_target_changed (frame_observer_target_changed);
2900 add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, _("\
2901 Set backtrace specific variables.\n\
2902 Configure backtrace variables such as the backtrace limit"),
2903 &set_backtrace_cmdlist, "set backtrace ",
2904 0/*allow-unknown*/, &setlist);
2905 add_prefix_cmd ("backtrace", class_maintenance, show_backtrace_cmd, _("\
2906 Show backtrace specific variables\n\
2907 Show backtrace variables such as the backtrace limit"),
2908 &show_backtrace_cmdlist, "show backtrace ",
2909 0/*allow-unknown*/, &showlist);
2911 add_setshow_boolean_cmd ("past-main", class_obscure,
2912 &backtrace_past_main, _("\
2913 Set whether backtraces should continue past \"main\"."), _("\
2914 Show whether backtraces should continue past \"main\"."), _("\
2915 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
2916 the backtrace at \"main\". Set this variable if you need to see the rest\n\
2917 of the stack trace."),
2919 show_backtrace_past_main,
2920 &set_backtrace_cmdlist,
2921 &show_backtrace_cmdlist);
2923 add_setshow_boolean_cmd ("past-entry", class_obscure,
2924 &backtrace_past_entry, _("\
2925 Set whether backtraces should continue past the entry point of a program."),
2927 Show whether backtraces should continue past the entry point of a program."),
2929 Normally there are no callers beyond the entry point of a program, so GDB\n\
2930 will terminate the backtrace there. Set this variable if you need to see\n\
2931 the rest of the stack trace."),
2933 show_backtrace_past_entry,
2934 &set_backtrace_cmdlist,
2935 &show_backtrace_cmdlist);
2937 add_setshow_uinteger_cmd ("limit", class_obscure,
2938 &backtrace_limit, _("\
2939 Set an upper bound on the number of backtrace levels."), _("\
2940 Show the upper bound on the number of backtrace levels."), _("\
2941 No more than the specified number of frames can be displayed or examined.\n\
2942 Literal \"unlimited\" or zero means no limit."),
2944 show_backtrace_limit,
2945 &set_backtrace_cmdlist,
2946 &show_backtrace_cmdlist);
2948 /* Debug this files internals. */
2949 add_setshow_zuinteger_cmd ("frame", class_maintenance, &frame_debug, _("\
2950 Set frame debugging."), _("\
2951 Show frame debugging."), _("\
2952 When non-zero, frame specific internal debugging is enabled."),
2955 &setdebuglist, &showdebuglist);