1 /* Cache and manage frames for GDB, the GNU debugger.
3 Copyright (C) 1986-2018 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "inferior.h" /* for inferior_ptid */
26 #include "user-regs.h"
27 #include "gdb_obstack.h"
28 #include "dummy-frame.h"
29 #include "sentinel-frame.h"
33 #include "frame-unwind.h"
34 #include "frame-base.h"
37 #include "observable.h"
39 #include "gdbthread.h"
41 #include "inline-frame.h"
42 #include "tracepoint.h"
46 /* The sentinel frame terminates the innermost end of the frame chain.
47 If unwound, it returns the information needed to construct an
50 The current frame, which is the innermost frame, can be found at
51 sentinel_frame->prev. */
53 static struct frame_info *sentinel_frame;
55 static struct frame_info *get_prev_frame_raw (struct frame_info *this_frame);
56 static const char *frame_stop_reason_symbol_string (enum unwind_stop_reason reason);
58 /* Status of some values cached in the frame_info object. */
60 enum cached_copy_status
62 /* Value is unknown. */
65 /* We have a value. */
68 /* Value was not saved. */
71 /* Value is unavailable. */
75 /* We keep a cache of stack frames, each of which is a "struct
76 frame_info". The innermost one gets allocated (in
77 wait_for_inferior) each time the inferior stops; sentinel_frame
78 points to it. Additional frames get allocated (in get_prev_frame)
79 as needed, and are chained through the next and prev fields. Any
80 time that the frame cache becomes invalid (most notably when we
81 execute something, but also if we change how we interpret the
82 frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything
83 which reads new symbols)), we should call reinit_frame_cache. */
87 /* Level of this frame. The inner-most (youngest) frame is at level
88 0. As you move towards the outer-most (oldest) frame, the level
89 increases. This is a cached value. It could just as easily be
90 computed by counting back from the selected frame to the inner
92 /* NOTE: cagney/2002-04-05: Perhaps a level of ``-1'' should be
93 reserved to indicate a bogus frame - one that has been created
94 just to keep GDB happy (GDB always needs a frame). For the
95 moment leave this as speculation. */
98 /* The frame's program space. */
99 struct program_space *pspace;
101 /* The frame's address space. */
102 const address_space *aspace;
104 /* The frame's low-level unwinder and corresponding cache. The
105 low-level unwinder is responsible for unwinding register values
106 for the previous frame. The low-level unwind methods are
107 selected based on the presence, or otherwise, of register unwind
108 information such as CFI. */
109 void *prologue_cache;
110 const struct frame_unwind *unwind;
112 /* Cached copy of the previous frame's architecture. */
116 struct gdbarch *arch;
119 /* Cached copy of the previous frame's resume address. */
121 enum cached_copy_status status;
125 /* Cached copy of the previous frame's function address. */
132 /* This frame's ID. */
136 struct frame_id value;
139 /* The frame's high-level base methods, and corresponding cache.
140 The high level base methods are selected based on the frame's
142 const struct frame_base *base;
145 /* Pointers to the next (down, inner, younger) and previous (up,
146 outer, older) frame_info's in the frame cache. */
147 struct frame_info *next; /* down, inner, younger */
149 struct frame_info *prev; /* up, outer, older */
151 /* The reason why we could not set PREV, or UNWIND_NO_REASON if we
152 could. Only valid when PREV_P is set. */
153 enum unwind_stop_reason stop_reason;
155 /* A frame specific string describing the STOP_REASON in more detail.
156 Only valid when PREV_P is set, but even then may still be NULL. */
157 const char *stop_string;
160 /* A frame stash used to speed up frame lookups. Create a hash table
161 to stash frames previously accessed from the frame cache for
162 quicker subsequent retrieval. The hash table is emptied whenever
163 the frame cache is invalidated. */
165 static htab_t frame_stash;
167 /* Internal function to calculate a hash from the frame_id addresses,
168 using as many valid addresses as possible. Frames below level 0
169 are not stored in the hash table. */
172 frame_addr_hash (const void *ap)
174 const struct frame_info *frame = (const struct frame_info *) ap;
175 const struct frame_id f_id = frame->this_id.value;
178 gdb_assert (f_id.stack_status != FID_STACK_INVALID
180 || f_id.special_addr_p);
182 if (f_id.stack_status == FID_STACK_VALID)
183 hash = iterative_hash (&f_id.stack_addr,
184 sizeof (f_id.stack_addr), hash);
185 if (f_id.code_addr_p)
186 hash = iterative_hash (&f_id.code_addr,
187 sizeof (f_id.code_addr), hash);
188 if (f_id.special_addr_p)
189 hash = iterative_hash (&f_id.special_addr,
190 sizeof (f_id.special_addr), hash);
195 /* Internal equality function for the hash table. This function
196 defers equality operations to frame_id_eq. */
199 frame_addr_hash_eq (const void *a, const void *b)
201 const struct frame_info *f_entry = (const struct frame_info *) a;
202 const struct frame_info *f_element = (const struct frame_info *) b;
204 return frame_id_eq (f_entry->this_id.value,
205 f_element->this_id.value);
208 /* Internal function to create the frame_stash hash table. 100 seems
209 to be a good compromise to start the hash table at. */
212 frame_stash_create (void)
214 frame_stash = htab_create (100,
220 /* Internal function to add a frame to the frame_stash hash table.
221 Returns false if a frame with the same ID was already stashed, true
225 frame_stash_add (struct frame_info *frame)
227 struct frame_info **slot;
229 /* Do not try to stash the sentinel frame. */
230 gdb_assert (frame->level >= 0);
232 slot = (struct frame_info **) htab_find_slot (frame_stash,
236 /* If we already have a frame in the stack with the same id, we
237 either have a stack cycle (corrupted stack?), or some bug
238 elsewhere in GDB. In any case, ignore the duplicate and return
239 an indication to the caller. */
247 /* Internal function to search the frame stash for an entry with the
248 given frame ID. If found, return that frame. Otherwise return
251 static struct frame_info *
252 frame_stash_find (struct frame_id id)
254 struct frame_info dummy;
255 struct frame_info *frame;
257 dummy.this_id.value = id;
258 frame = (struct frame_info *) htab_find (frame_stash, &dummy);
262 /* Internal function to invalidate the frame stash by removing all
263 entries in it. This only occurs when the frame cache is
267 frame_stash_invalidate (void)
269 htab_empty (frame_stash);
273 scoped_restore_selected_frame::scoped_restore_selected_frame ()
275 m_fid = get_frame_id (get_selected_frame (NULL));
279 scoped_restore_selected_frame::~scoped_restore_selected_frame ()
281 frame_info *frame = frame_find_by_id (m_fid);
283 warning (_("Unable to restore previously selected frame."));
285 select_frame (frame);
288 /* Flag to control debugging. */
290 unsigned int frame_debug;
292 show_frame_debug (struct ui_file *file, int from_tty,
293 struct cmd_list_element *c, const char *value)
295 fprintf_filtered (file, _("Frame debugging is %s.\n"), value);
298 /* Flag to indicate whether backtraces should stop at main et.al. */
300 static int backtrace_past_main;
302 show_backtrace_past_main (struct ui_file *file, int from_tty,
303 struct cmd_list_element *c, const char *value)
305 fprintf_filtered (file,
306 _("Whether backtraces should "
307 "continue past \"main\" is %s.\n"),
311 static int backtrace_past_entry;
313 show_backtrace_past_entry (struct ui_file *file, int from_tty,
314 struct cmd_list_element *c, const char *value)
316 fprintf_filtered (file, _("Whether backtraces should continue past the "
317 "entry point of a program is %s.\n"),
321 static unsigned int backtrace_limit = UINT_MAX;
323 show_backtrace_limit (struct ui_file *file, int from_tty,
324 struct cmd_list_element *c, const char *value)
326 fprintf_filtered (file,
327 _("An upper bound on the number "
328 "of backtrace levels is %s.\n"),
334 fprint_field (struct ui_file *file, const char *name, int p, CORE_ADDR addr)
337 fprintf_unfiltered (file, "%s=%s", name, hex_string (addr));
339 fprintf_unfiltered (file, "!%s", name);
343 fprint_frame_id (struct ui_file *file, struct frame_id id)
345 fprintf_unfiltered (file, "{");
347 if (id.stack_status == FID_STACK_INVALID)
348 fprintf_unfiltered (file, "!stack");
349 else if (id.stack_status == FID_STACK_UNAVAILABLE)
350 fprintf_unfiltered (file, "stack=<unavailable>");
351 else if (id.stack_status == FID_STACK_SENTINEL)
352 fprintf_unfiltered (file, "stack=<sentinel>");
354 fprintf_unfiltered (file, "stack=%s", hex_string (id.stack_addr));
355 fprintf_unfiltered (file, ",");
357 fprint_field (file, "code", id.code_addr_p, id.code_addr);
358 fprintf_unfiltered (file, ",");
360 fprint_field (file, "special", id.special_addr_p, id.special_addr);
362 if (id.artificial_depth)
363 fprintf_unfiltered (file, ",artificial=%d", id.artificial_depth);
365 fprintf_unfiltered (file, "}");
369 fprint_frame_type (struct ui_file *file, enum frame_type type)
374 fprintf_unfiltered (file, "NORMAL_FRAME");
377 fprintf_unfiltered (file, "DUMMY_FRAME");
380 fprintf_unfiltered (file, "INLINE_FRAME");
383 fprintf_unfiltered (file, "TAILCALL_FRAME");
386 fprintf_unfiltered (file, "SIGTRAMP_FRAME");
389 fprintf_unfiltered (file, "ARCH_FRAME");
392 fprintf_unfiltered (file, "SENTINEL_FRAME");
395 fprintf_unfiltered (file, "<unknown type>");
401 fprint_frame (struct ui_file *file, struct frame_info *fi)
405 fprintf_unfiltered (file, "<NULL frame>");
408 fprintf_unfiltered (file, "{");
409 fprintf_unfiltered (file, "level=%d", fi->level);
410 fprintf_unfiltered (file, ",");
411 fprintf_unfiltered (file, "type=");
412 if (fi->unwind != NULL)
413 fprint_frame_type (file, fi->unwind->type);
415 fprintf_unfiltered (file, "<unknown>");
416 fprintf_unfiltered (file, ",");
417 fprintf_unfiltered (file, "unwind=");
418 if (fi->unwind != NULL)
419 gdb_print_host_address (fi->unwind, file);
421 fprintf_unfiltered (file, "<unknown>");
422 fprintf_unfiltered (file, ",");
423 fprintf_unfiltered (file, "pc=");
424 if (fi->next == NULL || fi->next->prev_pc.status == CC_UNKNOWN)
425 fprintf_unfiltered (file, "<unknown>");
426 else if (fi->next->prev_pc.status == CC_VALUE)
427 fprintf_unfiltered (file, "%s",
428 hex_string (fi->next->prev_pc.value));
429 else if (fi->next->prev_pc.status == CC_NOT_SAVED)
430 val_print_not_saved (file);
431 else if (fi->next->prev_pc.status == CC_UNAVAILABLE)
432 val_print_unavailable (file);
433 fprintf_unfiltered (file, ",");
434 fprintf_unfiltered (file, "id=");
436 fprint_frame_id (file, fi->this_id.value);
438 fprintf_unfiltered (file, "<unknown>");
439 fprintf_unfiltered (file, ",");
440 fprintf_unfiltered (file, "func=");
441 if (fi->next != NULL && fi->next->prev_func.p)
442 fprintf_unfiltered (file, "%s", hex_string (fi->next->prev_func.addr));
444 fprintf_unfiltered (file, "<unknown>");
445 fprintf_unfiltered (file, "}");
448 /* Given FRAME, return the enclosing frame as found in real frames read-in from
449 inferior memory. Skip any previous frames which were made up by GDB.
450 Return FRAME if FRAME is a non-artificial frame.
451 Return NULL if FRAME is the start of an artificial-only chain. */
453 static struct frame_info *
454 skip_artificial_frames (struct frame_info *frame)
456 /* Note we use get_prev_frame_always, and not get_prev_frame. The
457 latter will truncate the frame chain, leading to this function
458 unintentionally returning a null_frame_id (e.g., when the user
459 sets a backtrace limit).
461 Note that for record targets we may get a frame chain that consists
462 of artificial frames only. */
463 while (get_frame_type (frame) == INLINE_FRAME
464 || get_frame_type (frame) == TAILCALL_FRAME)
466 frame = get_prev_frame_always (frame);
475 skip_unwritable_frames (struct frame_info *frame)
477 while (gdbarch_code_of_frame_writable (get_frame_arch (frame), frame) == 0)
479 frame = get_prev_frame (frame);
490 skip_tailcall_frames (struct frame_info *frame)
492 while (get_frame_type (frame) == TAILCALL_FRAME)
494 /* Note that for record targets we may get a frame chain that consists of
495 tailcall frames only. */
496 frame = get_prev_frame (frame);
504 /* Compute the frame's uniq ID that can be used to, later, re-find the
508 compute_frame_id (struct frame_info *fi)
510 gdb_assert (!fi->this_id.p);
513 fprintf_unfiltered (gdb_stdlog, "{ compute_frame_id (fi=%d) ",
515 /* Find the unwinder. */
516 if (fi->unwind == NULL)
517 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
518 /* Find THIS frame's ID. */
519 /* Default to outermost if no ID is found. */
520 fi->this_id.value = outer_frame_id;
521 fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value);
522 gdb_assert (frame_id_p (fi->this_id.value));
526 fprintf_unfiltered (gdb_stdlog, "-> ");
527 fprint_frame_id (gdb_stdlog, fi->this_id.value);
528 fprintf_unfiltered (gdb_stdlog, " }\n");
532 /* Return a frame uniq ID that can be used to, later, re-find the
536 get_frame_id (struct frame_info *fi)
539 return null_frame_id;
545 /* If we haven't computed the frame id yet, then it must be that
546 this is the current frame. Compute it now, and stash the
547 result. The IDs of other frames are computed as soon as
548 they're created, in order to detect cycles. See
549 get_prev_frame_if_no_cycle. */
550 gdb_assert (fi->level == 0);
553 compute_frame_id (fi);
555 /* Since this is the first frame in the chain, this should
557 stashed = frame_stash_add (fi);
558 gdb_assert (stashed);
561 return fi->this_id.value;
565 get_stack_frame_id (struct frame_info *next_frame)
567 return get_frame_id (skip_artificial_frames (next_frame));
571 frame_unwind_caller_id (struct frame_info *next_frame)
573 struct frame_info *this_frame;
575 /* Use get_prev_frame_always, and not get_prev_frame. The latter
576 will truncate the frame chain, leading to this function
577 unintentionally returning a null_frame_id (e.g., when a caller
578 requests the frame ID of "main()"s caller. */
580 next_frame = skip_artificial_frames (next_frame);
581 if (next_frame == NULL)
582 return null_frame_id;
584 this_frame = get_prev_frame_always (next_frame);
586 return get_frame_id (skip_artificial_frames (this_frame));
588 return null_frame_id;
591 const struct frame_id null_frame_id = { 0 }; /* All zeros. */
592 const struct frame_id sentinel_frame_id = { 0, 0, 0, FID_STACK_SENTINEL, 0, 1, 0 };
593 const struct frame_id outer_frame_id = { 0, 0, 0, FID_STACK_INVALID, 0, 1, 0 };
596 frame_id_build_special (CORE_ADDR stack_addr, CORE_ADDR code_addr,
597 CORE_ADDR special_addr)
599 struct frame_id id = null_frame_id;
601 id.stack_addr = stack_addr;
602 id.stack_status = FID_STACK_VALID;
603 id.code_addr = code_addr;
605 id.special_addr = special_addr;
606 id.special_addr_p = 1;
613 frame_id_build_unavailable_stack (CORE_ADDR code_addr)
615 struct frame_id id = null_frame_id;
617 id.stack_status = FID_STACK_UNAVAILABLE;
618 id.code_addr = code_addr;
626 frame_id_build_unavailable_stack_special (CORE_ADDR code_addr,
627 CORE_ADDR special_addr)
629 struct frame_id id = null_frame_id;
631 id.stack_status = FID_STACK_UNAVAILABLE;
632 id.code_addr = code_addr;
634 id.special_addr = special_addr;
635 id.special_addr_p = 1;
640 frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr)
642 struct frame_id id = null_frame_id;
644 id.stack_addr = stack_addr;
645 id.stack_status = FID_STACK_VALID;
646 id.code_addr = code_addr;
652 frame_id_build_wild (CORE_ADDR stack_addr)
654 struct frame_id id = null_frame_id;
656 id.stack_addr = stack_addr;
657 id.stack_status = FID_STACK_VALID;
662 frame_id_p (struct frame_id l)
666 /* The frame is valid iff it has a valid stack address. */
667 p = l.stack_status != FID_STACK_INVALID;
668 /* outer_frame_id is also valid. */
669 if (!p && memcmp (&l, &outer_frame_id, sizeof (l)) == 0)
673 fprintf_unfiltered (gdb_stdlog, "{ frame_id_p (l=");
674 fprint_frame_id (gdb_stdlog, l);
675 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", p);
681 frame_id_artificial_p (struct frame_id l)
686 return (l.artificial_depth != 0);
690 frame_id_eq (struct frame_id l, struct frame_id r)
694 if (l.stack_status == FID_STACK_INVALID && l.special_addr_p
695 && r.stack_status == FID_STACK_INVALID && r.special_addr_p)
696 /* The outermost frame marker is equal to itself. This is the
697 dodgy thing about outer_frame_id, since between execution steps
698 we might step into another function - from which we can't
699 unwind either. More thought required to get rid of
702 else if (l.stack_status == FID_STACK_INVALID
703 || r.stack_status == FID_STACK_INVALID)
704 /* Like a NaN, if either ID is invalid, the result is false.
705 Note that a frame ID is invalid iff it is the null frame ID. */
707 else if (l.stack_status != r.stack_status || l.stack_addr != r.stack_addr)
708 /* If .stack addresses are different, the frames are different. */
710 else if (l.code_addr_p && r.code_addr_p && l.code_addr != r.code_addr)
711 /* An invalid code addr is a wild card. If .code addresses are
712 different, the frames are different. */
714 else if (l.special_addr_p && r.special_addr_p
715 && l.special_addr != r.special_addr)
716 /* An invalid special addr is a wild card (or unused). Otherwise
717 if special addresses are different, the frames are different. */
719 else if (l.artificial_depth != r.artificial_depth)
720 /* If artifical depths are different, the frames must be different. */
723 /* Frames are equal. */
728 fprintf_unfiltered (gdb_stdlog, "{ frame_id_eq (l=");
729 fprint_frame_id (gdb_stdlog, l);
730 fprintf_unfiltered (gdb_stdlog, ",r=");
731 fprint_frame_id (gdb_stdlog, r);
732 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", eq);
737 /* Safety net to check whether frame ID L should be inner to
738 frame ID R, according to their stack addresses.
740 This method cannot be used to compare arbitrary frames, as the
741 ranges of valid stack addresses may be discontiguous (e.g. due
744 However, it can be used as safety net to discover invalid frame
745 IDs in certain circumstances. Assuming that NEXT is the immediate
746 inner frame to THIS and that NEXT and THIS are both NORMAL frames:
748 * The stack address of NEXT must be inner-than-or-equal to the stack
751 Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind
754 * If NEXT and THIS have different stack addresses, no other frame
755 in the frame chain may have a stack address in between.
757 Therefore, if frame_id_inner (TEST, THIS) holds, but
758 frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer
759 to a valid frame in the frame chain.
761 The sanity checks above cannot be performed when a SIGTRAMP frame
762 is involved, because signal handlers might be executed on a different
763 stack than the stack used by the routine that caused the signal
764 to be raised. This can happen for instance when a thread exceeds
765 its maximum stack size. In this case, certain compilers implement
766 a stack overflow strategy that cause the handler to be run on a
770 frame_id_inner (struct gdbarch *gdbarch, struct frame_id l, struct frame_id r)
774 if (l.stack_status != FID_STACK_VALID || r.stack_status != FID_STACK_VALID)
775 /* Like NaN, any operation involving an invalid ID always fails.
776 Likewise if either ID has an unavailable stack address. */
778 else if (l.artificial_depth > r.artificial_depth
779 && l.stack_addr == r.stack_addr
780 && l.code_addr_p == r.code_addr_p
781 && l.special_addr_p == r.special_addr_p
782 && l.special_addr == r.special_addr)
784 /* Same function, different inlined functions. */
785 const struct block *lb, *rb;
787 gdb_assert (l.code_addr_p && r.code_addr_p);
789 lb = block_for_pc (l.code_addr);
790 rb = block_for_pc (r.code_addr);
792 if (lb == NULL || rb == NULL)
793 /* Something's gone wrong. */
796 /* This will return true if LB and RB are the same block, or
797 if the block with the smaller depth lexically encloses the
798 block with the greater depth. */
799 inner = contained_in (lb, rb);
802 /* Only return non-zero when strictly inner than. Note that, per
803 comment in "frame.h", there is some fuzz here. Frameless
804 functions are not strictly inner than (same .stack but
805 different .code and/or .special address). */
806 inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr);
809 fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l=");
810 fprint_frame_id (gdb_stdlog, l);
811 fprintf_unfiltered (gdb_stdlog, ",r=");
812 fprint_frame_id (gdb_stdlog, r);
813 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", inner);
819 frame_find_by_id (struct frame_id id)
821 struct frame_info *frame, *prev_frame;
823 /* ZERO denotes the null frame, let the caller decide what to do
824 about it. Should it instead return get_current_frame()? */
825 if (!frame_id_p (id))
828 /* Check for the sentinel frame. */
829 if (frame_id_eq (id, sentinel_frame_id))
830 return sentinel_frame;
832 /* Try using the frame stash first. Finding it there removes the need
833 to perform the search by looping over all frames, which can be very
834 CPU-intensive if the number of frames is very high (the loop is O(n)
835 and get_prev_frame performs a series of checks that are relatively
836 expensive). This optimization is particularly useful when this function
837 is called from another function (such as value_fetch_lazy, case
838 VALUE_LVAL (val) == lval_register) which already loops over all frames,
839 making the overall behavior O(n^2). */
840 frame = frame_stash_find (id);
844 for (frame = get_current_frame (); ; frame = prev_frame)
846 struct frame_id self = get_frame_id (frame);
848 if (frame_id_eq (id, self))
849 /* An exact match. */
852 prev_frame = get_prev_frame (frame);
856 /* As a safety net to avoid unnecessary backtracing while trying
857 to find an invalid ID, we check for a common situation where
858 we can detect from comparing stack addresses that no other
859 frame in the current frame chain can have this ID. See the
860 comment at frame_id_inner for details. */
861 if (get_frame_type (frame) == NORMAL_FRAME
862 && !frame_id_inner (get_frame_arch (frame), id, self)
863 && frame_id_inner (get_frame_arch (prev_frame), id,
864 get_frame_id (prev_frame)))
871 frame_unwind_pc (struct frame_info *this_frame)
873 if (this_frame->prev_pc.status == CC_UNKNOWN)
875 if (gdbarch_unwind_pc_p (frame_unwind_arch (this_frame)))
877 struct gdbarch *prev_gdbarch;
881 /* The right way. The `pure' way. The one true way. This
882 method depends solely on the register-unwind code to
883 determine the value of registers in THIS frame, and hence
884 the value of this frame's PC (resume address). A typical
885 implementation is no more than:
887 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf);
888 return extract_unsigned_integer (buf, size of ISA_PC_REGNUM);
890 Note: this method is very heavily dependent on a correct
891 register-unwind implementation, it pays to fix that
892 method first; this method is frame type agnostic, since
893 it only deals with register values, it works with any
894 frame. This is all in stark contrast to the old
895 FRAME_SAVED_PC which would try to directly handle all the
896 different ways that a PC could be unwound. */
897 prev_gdbarch = frame_unwind_arch (this_frame);
901 pc = gdbarch_unwind_pc (prev_gdbarch, this_frame);
904 CATCH (ex, RETURN_MASK_ERROR)
906 if (ex.error == NOT_AVAILABLE_ERROR)
908 this_frame->prev_pc.status = CC_UNAVAILABLE;
911 fprintf_unfiltered (gdb_stdlog,
912 "{ frame_unwind_pc (this_frame=%d)"
913 " -> <unavailable> }\n",
916 else if (ex.error == OPTIMIZED_OUT_ERROR)
918 this_frame->prev_pc.status = CC_NOT_SAVED;
921 fprintf_unfiltered (gdb_stdlog,
922 "{ frame_unwind_pc (this_frame=%d)"
923 " -> <not saved> }\n",
927 throw_exception (ex);
933 this_frame->prev_pc.value = pc;
934 this_frame->prev_pc.status = CC_VALUE;
936 fprintf_unfiltered (gdb_stdlog,
937 "{ frame_unwind_pc (this_frame=%d) "
940 hex_string (this_frame->prev_pc.value));
944 internal_error (__FILE__, __LINE__, _("No unwind_pc method"));
947 if (this_frame->prev_pc.status == CC_VALUE)
948 return this_frame->prev_pc.value;
949 else if (this_frame->prev_pc.status == CC_UNAVAILABLE)
950 throw_error (NOT_AVAILABLE_ERROR, _("PC not available"));
951 else if (this_frame->prev_pc.status == CC_NOT_SAVED)
952 throw_error (OPTIMIZED_OUT_ERROR, _("PC not saved"));
954 internal_error (__FILE__, __LINE__,
955 "unexpected prev_pc status: %d",
956 (int) this_frame->prev_pc.status);
960 frame_unwind_caller_pc (struct frame_info *this_frame)
962 this_frame = skip_artificial_frames (this_frame);
964 /* We must have a non-artificial frame. The caller is supposed to check
965 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
967 gdb_assert (this_frame != NULL);
969 return frame_unwind_pc (this_frame);
973 get_frame_func_if_available (struct frame_info *this_frame, CORE_ADDR *pc)
975 struct frame_info *next_frame = this_frame->next;
977 if (!next_frame->prev_func.p)
979 CORE_ADDR addr_in_block;
981 /* Make certain that this, and not the adjacent, function is
983 if (!get_frame_address_in_block_if_available (this_frame, &addr_in_block))
985 next_frame->prev_func.p = -1;
987 fprintf_unfiltered (gdb_stdlog,
988 "{ get_frame_func (this_frame=%d)"
989 " -> unavailable }\n",
994 next_frame->prev_func.p = 1;
995 next_frame->prev_func.addr = get_pc_function_start (addr_in_block);
997 fprintf_unfiltered (gdb_stdlog,
998 "{ get_frame_func (this_frame=%d) -> %s }\n",
1000 hex_string (next_frame->prev_func.addr));
1004 if (next_frame->prev_func.p < 0)
1011 *pc = next_frame->prev_func.addr;
1017 get_frame_func (struct frame_info *this_frame)
1021 if (!get_frame_func_if_available (this_frame, &pc))
1022 throw_error (NOT_AVAILABLE_ERROR, _("PC not available"));
1027 static enum register_status
1028 do_frame_register_read (void *src, int regnum, gdb_byte *buf)
1030 if (!deprecated_frame_register_read ((struct frame_info *) src, regnum, buf))
1031 return REG_UNAVAILABLE;
1036 std::unique_ptr<readonly_detached_regcache>
1037 frame_save_as_regcache (struct frame_info *this_frame)
1039 std::unique_ptr<readonly_detached_regcache> regcache
1040 (new readonly_detached_regcache (get_frame_arch (this_frame),
1041 do_frame_register_read, this_frame));
1047 frame_pop (struct frame_info *this_frame)
1049 struct frame_info *prev_frame;
1051 if (get_frame_type (this_frame) == DUMMY_FRAME)
1053 /* Popping a dummy frame involves restoring more than just registers.
1054 dummy_frame_pop does all the work. */
1055 dummy_frame_pop (get_frame_id (this_frame), inferior_ptid);
1059 /* Ensure that we have a frame to pop to. */
1060 prev_frame = get_prev_frame_always (this_frame);
1063 error (_("Cannot pop the initial frame."));
1065 /* Ignore TAILCALL_FRAME type frames, they were executed already before
1066 entering THISFRAME. */
1067 prev_frame = skip_tailcall_frames (prev_frame);
1069 if (prev_frame == NULL)
1070 error (_("Cannot find the caller frame."));
1072 /* Make a copy of all the register values unwound from this frame.
1073 Save them in a scratch buffer so that there isn't a race between
1074 trying to extract the old values from the current regcache while
1075 at the same time writing new values into that same cache. */
1076 std::unique_ptr<readonly_detached_regcache> scratch
1077 = frame_save_as_regcache (prev_frame);
1079 /* FIXME: cagney/2003-03-16: It should be possible to tell the
1080 target's register cache that it is about to be hit with a burst
1081 register transfer and that the sequence of register writes should
1082 be batched. The pair target_prepare_to_store() and
1083 target_store_registers() kind of suggest this functionality.
1084 Unfortunately, they don't implement it. Their lack of a formal
1085 definition can lead to targets writing back bogus values
1086 (arguably a bug in the target code mind). */
1087 /* Now copy those saved registers into the current regcache. */
1088 get_current_regcache ()->restore (scratch.get ());
1090 /* We've made right mess of GDB's local state, just discard
1092 reinit_frame_cache ();
1096 frame_register_unwind (struct frame_info *frame, int regnum,
1097 int *optimizedp, int *unavailablep,
1098 enum lval_type *lvalp, CORE_ADDR *addrp,
1099 int *realnump, gdb_byte *bufferp)
1101 struct value *value;
1103 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1104 that the value proper does not need to be fetched. */
1105 gdb_assert (optimizedp != NULL);
1106 gdb_assert (lvalp != NULL);
1107 gdb_assert (addrp != NULL);
1108 gdb_assert (realnump != NULL);
1109 /* gdb_assert (bufferp != NULL); */
1111 value = frame_unwind_register_value (frame, regnum);
1113 gdb_assert (value != NULL);
1115 *optimizedp = value_optimized_out (value);
1116 *unavailablep = !value_entirely_available (value);
1117 *lvalp = VALUE_LVAL (value);
1118 *addrp = value_address (value);
1119 if (*lvalp == lval_register)
1120 *realnump = VALUE_REGNUM (value);
1126 if (!*optimizedp && !*unavailablep)
1127 memcpy (bufferp, value_contents_all (value),
1128 TYPE_LENGTH (value_type (value)));
1130 memset (bufferp, 0, TYPE_LENGTH (value_type (value)));
1133 /* Dispose of the new value. This prevents watchpoints from
1134 trying to watch the saved frame pointer. */
1135 release_value (value);
1139 frame_register (struct frame_info *frame, int regnum,
1140 int *optimizedp, int *unavailablep, enum lval_type *lvalp,
1141 CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp)
1143 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
1144 that the value proper does not need to be fetched. */
1145 gdb_assert (optimizedp != NULL);
1146 gdb_assert (lvalp != NULL);
1147 gdb_assert (addrp != NULL);
1148 gdb_assert (realnump != NULL);
1149 /* gdb_assert (bufferp != NULL); */
1151 /* Obtain the register value by unwinding the register from the next
1152 (more inner frame). */
1153 gdb_assert (frame != NULL && frame->next != NULL);
1154 frame_register_unwind (frame->next, regnum, optimizedp, unavailablep,
1155 lvalp, addrp, realnump, bufferp);
1159 frame_unwind_register (struct frame_info *frame, int regnum, gdb_byte *buf)
1165 enum lval_type lval;
1167 frame_register_unwind (frame, regnum, &optimized, &unavailable,
1168 &lval, &addr, &realnum, buf);
1171 throw_error (OPTIMIZED_OUT_ERROR,
1172 _("Register %d was not saved"), regnum);
1174 throw_error (NOT_AVAILABLE_ERROR,
1175 _("Register %d is not available"), regnum);
1179 get_frame_register (struct frame_info *frame,
1180 int regnum, gdb_byte *buf)
1182 frame_unwind_register (frame->next, regnum, buf);
1186 frame_unwind_register_value (struct frame_info *frame, int regnum)
1188 struct gdbarch *gdbarch;
1189 struct value *value;
1191 gdb_assert (frame != NULL);
1192 gdbarch = frame_unwind_arch (frame);
1196 fprintf_unfiltered (gdb_stdlog,
1197 "{ frame_unwind_register_value "
1198 "(frame=%d,regnum=%d(%s),...) ",
1199 frame->level, regnum,
1200 user_reg_map_regnum_to_name (gdbarch, regnum));
1203 /* Find the unwinder. */
1204 if (frame->unwind == NULL)
1205 frame_unwind_find_by_frame (frame, &frame->prologue_cache);
1207 /* Ask this frame to unwind its register. */
1208 value = frame->unwind->prev_register (frame, &frame->prologue_cache, regnum);
1212 fprintf_unfiltered (gdb_stdlog, "->");
1213 if (value_optimized_out (value))
1215 fprintf_unfiltered (gdb_stdlog, " ");
1216 val_print_optimized_out (value, gdb_stdlog);
1220 if (VALUE_LVAL (value) == lval_register)
1221 fprintf_unfiltered (gdb_stdlog, " register=%d",
1222 VALUE_REGNUM (value));
1223 else if (VALUE_LVAL (value) == lval_memory)
1224 fprintf_unfiltered (gdb_stdlog, " address=%s",
1226 value_address (value)));
1228 fprintf_unfiltered (gdb_stdlog, " computed");
1230 if (value_lazy (value))
1231 fprintf_unfiltered (gdb_stdlog, " lazy");
1235 const gdb_byte *buf = value_contents (value);
1237 fprintf_unfiltered (gdb_stdlog, " bytes=");
1238 fprintf_unfiltered (gdb_stdlog, "[");
1239 for (i = 0; i < register_size (gdbarch, regnum); i++)
1240 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
1241 fprintf_unfiltered (gdb_stdlog, "]");
1245 fprintf_unfiltered (gdb_stdlog, " }\n");
1252 get_frame_register_value (struct frame_info *frame, int regnum)
1254 return frame_unwind_register_value (frame->next, regnum);
1258 frame_unwind_register_signed (struct frame_info *frame, int regnum)
1260 struct gdbarch *gdbarch = frame_unwind_arch (frame);
1261 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1262 int size = register_size (gdbarch, regnum);
1263 struct value *value = frame_unwind_register_value (frame, regnum);
1265 gdb_assert (value != NULL);
1267 if (value_optimized_out (value))
1269 throw_error (OPTIMIZED_OUT_ERROR,
1270 _("Register %d was not saved"), regnum);
1272 if (!value_entirely_available (value))
1274 throw_error (NOT_AVAILABLE_ERROR,
1275 _("Register %d is not available"), regnum);
1278 LONGEST r = extract_signed_integer (value_contents_all (value), size,
1281 release_value (value);
1286 get_frame_register_signed (struct frame_info *frame, int regnum)
1288 return frame_unwind_register_signed (frame->next, regnum);
1292 frame_unwind_register_unsigned (struct frame_info *frame, int regnum)
1294 struct gdbarch *gdbarch = frame_unwind_arch (frame);
1295 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1296 int size = register_size (gdbarch, regnum);
1297 struct value *value = frame_unwind_register_value (frame, regnum);
1299 gdb_assert (value != NULL);
1301 if (value_optimized_out (value))
1303 throw_error (OPTIMIZED_OUT_ERROR,
1304 _("Register %d was not saved"), regnum);
1306 if (!value_entirely_available (value))
1308 throw_error (NOT_AVAILABLE_ERROR,
1309 _("Register %d is not available"), regnum);
1312 ULONGEST r = extract_unsigned_integer (value_contents_all (value), size,
1315 release_value (value);
1320 get_frame_register_unsigned (struct frame_info *frame, int regnum)
1322 return frame_unwind_register_unsigned (frame->next, regnum);
1326 read_frame_register_unsigned (struct frame_info *frame, int regnum,
1329 struct value *regval = get_frame_register_value (frame, regnum);
1331 if (!value_optimized_out (regval)
1332 && value_entirely_available (regval))
1334 struct gdbarch *gdbarch = get_frame_arch (frame);
1335 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1336 int size = register_size (gdbarch, VALUE_REGNUM (regval));
1338 *val = extract_unsigned_integer (value_contents (regval), size, byte_order);
1346 put_frame_register (struct frame_info *frame, int regnum,
1347 const gdb_byte *buf)
1349 struct gdbarch *gdbarch = get_frame_arch (frame);
1353 enum lval_type lval;
1356 frame_register (frame, regnum, &optim, &unavail,
1357 &lval, &addr, &realnum, NULL);
1359 error (_("Attempt to assign to a register that was not saved."));
1364 write_memory (addr, buf, register_size (gdbarch, regnum));
1368 regcache_cooked_write (get_current_regcache (), realnum, buf);
1371 error (_("Attempt to assign to an unmodifiable value."));
1375 /* This function is deprecated. Use get_frame_register_value instead,
1376 which provides more accurate information.
1378 Find and return the value of REGNUM for the specified stack frame.
1379 The number of bytes copied is REGISTER_SIZE (REGNUM).
1381 Returns 0 if the register value could not be found. */
1384 deprecated_frame_register_read (struct frame_info *frame, int regnum,
1389 enum lval_type lval;
1393 frame_register (frame, regnum, &optimized, &unavailable,
1394 &lval, &addr, &realnum, myaddr);
1396 return !optimized && !unavailable;
1400 get_frame_register_bytes (struct frame_info *frame, int regnum,
1401 CORE_ADDR offset, int len, gdb_byte *myaddr,
1402 int *optimizedp, int *unavailablep)
1404 struct gdbarch *gdbarch = get_frame_arch (frame);
1409 /* Skip registers wholly inside of OFFSET. */
1410 while (offset >= register_size (gdbarch, regnum))
1412 offset -= register_size (gdbarch, regnum);
1416 /* Ensure that we will not read beyond the end of the register file.
1417 This can only ever happen if the debug information is bad. */
1419 numregs = gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
1420 for (i = regnum; i < numregs; i++)
1422 int thissize = register_size (gdbarch, i);
1425 break; /* This register is not available on this architecture. */
1426 maxsize += thissize;
1429 error (_("Bad debug information detected: "
1430 "Attempt to read %d bytes from registers."), len);
1432 /* Copy the data. */
1435 int curr_len = register_size (gdbarch, regnum) - offset;
1440 if (curr_len == register_size (gdbarch, regnum))
1442 enum lval_type lval;
1446 frame_register (frame, regnum, optimizedp, unavailablep,
1447 &lval, &addr, &realnum, myaddr);
1448 if (*optimizedp || *unavailablep)
1453 struct value *value = frame_unwind_register_value (frame->next,
1455 gdb_assert (value != NULL);
1456 *optimizedp = value_optimized_out (value);
1457 *unavailablep = !value_entirely_available (value);
1459 if (*optimizedp || *unavailablep)
1461 release_value (value);
1464 memcpy (myaddr, value_contents_all (value) + offset, curr_len);
1465 release_value (value);
1480 put_frame_register_bytes (struct frame_info *frame, int regnum,
1481 CORE_ADDR offset, int len, const gdb_byte *myaddr)
1483 struct gdbarch *gdbarch = get_frame_arch (frame);
1485 /* Skip registers wholly inside of OFFSET. */
1486 while (offset >= register_size (gdbarch, regnum))
1488 offset -= register_size (gdbarch, regnum);
1492 /* Copy the data. */
1495 int curr_len = register_size (gdbarch, regnum) - offset;
1500 if (curr_len == register_size (gdbarch, regnum))
1502 put_frame_register (frame, regnum, myaddr);
1506 struct value *value = frame_unwind_register_value (frame->next,
1508 gdb_assert (value != NULL);
1510 memcpy ((char *) value_contents_writeable (value) + offset, myaddr,
1512 put_frame_register (frame, regnum, value_contents_raw (value));
1513 release_value (value);
1523 /* Create a sentinel frame. */
1525 static struct frame_info *
1526 create_sentinel_frame (struct program_space *pspace, struct regcache *regcache)
1528 struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
1531 frame->pspace = pspace;
1532 frame->aspace = regcache->aspace ();
1533 /* Explicitly initialize the sentinel frame's cache. Provide it
1534 with the underlying regcache. In the future additional
1535 information, such as the frame's thread will be added. */
1536 frame->prologue_cache = sentinel_frame_cache (regcache);
1537 /* For the moment there is only one sentinel frame implementation. */
1538 frame->unwind = &sentinel_frame_unwind;
1539 /* Link this frame back to itself. The frame is self referential
1540 (the unwound PC is the same as the pc), so make it so. */
1541 frame->next = frame;
1542 /* The sentinel frame has a special ID. */
1543 frame->this_id.p = 1;
1544 frame->this_id.value = sentinel_frame_id;
1547 fprintf_unfiltered (gdb_stdlog, "{ create_sentinel_frame (...) -> ");
1548 fprint_frame (gdb_stdlog, frame);
1549 fprintf_unfiltered (gdb_stdlog, " }\n");
1554 /* Cache for frame addresses already read by gdb. Valid only while
1555 inferior is stopped. Control variables for the frame cache should
1556 be local to this module. */
1558 static struct obstack frame_cache_obstack;
1561 frame_obstack_zalloc (unsigned long size)
1563 void *data = obstack_alloc (&frame_cache_obstack, size);
1565 memset (data, 0, size);
1569 static struct frame_info *get_prev_frame_always_1 (struct frame_info *this_frame);
1572 get_current_frame (void)
1574 struct frame_info *current_frame;
1576 /* First check, and report, the lack of registers. Having GDB
1577 report "No stack!" or "No memory" when the target doesn't even
1578 have registers is very confusing. Besides, "printcmd.exp"
1579 explicitly checks that ``print $pc'' with no registers prints "No
1581 if (!target_has_registers)
1582 error (_("No registers."));
1583 if (!target_has_stack)
1584 error (_("No stack."));
1585 if (!target_has_memory)
1586 error (_("No memory."));
1587 /* Traceframes are effectively a substitute for the live inferior. */
1588 if (get_traceframe_number () < 0)
1589 validate_registers_access ();
1591 if (sentinel_frame == NULL)
1593 create_sentinel_frame (current_program_space, get_current_regcache ());
1595 /* Set the current frame before computing the frame id, to avoid
1596 recursion inside compute_frame_id, in case the frame's
1597 unwinder decides to do a symbol lookup (which depends on the
1598 selected frame's block).
1600 This call must always succeed. In particular, nothing inside
1601 get_prev_frame_always_1 should try to unwind from the
1602 sentinel frame, because that could fail/throw, and we always
1603 want to leave with the current frame created and linked in --
1604 we should never end up with the sentinel frame as outermost
1606 current_frame = get_prev_frame_always_1 (sentinel_frame);
1607 gdb_assert (current_frame != NULL);
1609 return current_frame;
1612 /* The "selected" stack frame is used by default for local and arg
1613 access. May be zero, for no selected frame. */
1615 static struct frame_info *selected_frame;
1618 has_stack_frames (void)
1620 if (!target_has_registers || !target_has_stack || !target_has_memory)
1623 /* Traceframes are effectively a substitute for the live inferior. */
1624 if (get_traceframe_number () < 0)
1626 /* No current inferior, no frame. */
1627 if (ptid_equal (inferior_ptid, null_ptid))
1630 /* Don't try to read from a dead thread. */
1631 if (is_exited (inferior_ptid))
1634 /* ... or from a spinning thread. */
1635 if (is_executing (inferior_ptid))
1642 /* Return the selected frame. Always non-NULL (unless there isn't an
1643 inferior sufficient for creating a frame) in which case an error is
1647 get_selected_frame (const char *message)
1649 if (selected_frame == NULL)
1651 if (message != NULL && !has_stack_frames ())
1652 error (("%s"), message);
1653 /* Hey! Don't trust this. It should really be re-finding the
1654 last selected frame of the currently selected thread. This,
1655 though, is better than nothing. */
1656 select_frame (get_current_frame ());
1658 /* There is always a frame. */
1659 gdb_assert (selected_frame != NULL);
1660 return selected_frame;
1663 /* If there is a selected frame, return it. Otherwise, return NULL. */
1666 get_selected_frame_if_set (void)
1668 return selected_frame;
1671 /* This is a variant of get_selected_frame() which can be called when
1672 the inferior does not have a frame; in that case it will return
1673 NULL instead of calling error(). */
1676 deprecated_safe_get_selected_frame (void)
1678 if (!has_stack_frames ())
1680 return get_selected_frame (NULL);
1683 /* Select frame FI (or NULL - to invalidate the current frame). */
1686 select_frame (struct frame_info *fi)
1688 selected_frame = fi;
1689 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
1690 frame is being invalidated. */
1692 /* FIXME: kseitz/2002-08-28: It would be nice to call
1693 selected_frame_level_changed_event() right here, but due to limitations
1694 in the current interfaces, we would end up flooding UIs with events
1695 because select_frame() is used extensively internally.
1697 Once we have frame-parameterized frame (and frame-related) commands,
1698 the event notification can be moved here, since this function will only
1699 be called when the user's selected frame is being changed. */
1701 /* Ensure that symbols for this frame are read in. Also, determine the
1702 source language of this frame, and switch to it if desired. */
1707 /* We retrieve the frame's symtab by using the frame PC.
1708 However we cannot use the frame PC as-is, because it usually
1709 points to the instruction following the "call", which is
1710 sometimes the first instruction of another function. So we
1711 rely on get_frame_address_in_block() which provides us with a
1712 PC which is guaranteed to be inside the frame's code
1714 if (get_frame_address_in_block_if_available (fi, &pc))
1716 struct compunit_symtab *cust = find_pc_compunit_symtab (pc);
1719 && compunit_language (cust) != current_language->la_language
1720 && compunit_language (cust) != language_unknown
1721 && language_mode == language_mode_auto)
1722 set_language (compunit_language (cust));
1727 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
1728 Always returns a non-NULL value. */
1731 create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
1733 struct frame_info *fi;
1737 fprintf_unfiltered (gdb_stdlog,
1738 "{ create_new_frame (addr=%s, pc=%s) ",
1739 hex_string (addr), hex_string (pc));
1742 fi = FRAME_OBSTACK_ZALLOC (struct frame_info);
1744 fi->next = create_sentinel_frame (current_program_space,
1745 get_current_regcache ());
1747 /* Set/update this frame's cached PC value, found in the next frame.
1748 Do this before looking for this frame's unwinder. A sniffer is
1749 very likely to read this, and the corresponding unwinder is
1750 entitled to rely that the PC doesn't magically change. */
1751 fi->next->prev_pc.value = pc;
1752 fi->next->prev_pc.status = CC_VALUE;
1754 /* We currently assume that frame chain's can't cross spaces. */
1755 fi->pspace = fi->next->pspace;
1756 fi->aspace = fi->next->aspace;
1758 /* Select/initialize both the unwind function and the frame's type
1760 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
1763 fi->this_id.value = frame_id_build (addr, pc);
1767 fprintf_unfiltered (gdb_stdlog, "-> ");
1768 fprint_frame (gdb_stdlog, fi);
1769 fprintf_unfiltered (gdb_stdlog, " }\n");
1775 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
1776 innermost frame). Be careful to not fall off the bottom of the
1777 frame chain and onto the sentinel frame. */
1780 get_next_frame (struct frame_info *this_frame)
1782 if (this_frame->level > 0)
1783 return this_frame->next;
1788 /* Return the frame that THIS_FRAME calls. If THIS_FRAME is the
1789 innermost (i.e. current) frame, return the sentinel frame. Thus,
1790 unlike get_next_frame(), NULL will never be returned. */
1793 get_next_frame_sentinel_okay (struct frame_info *this_frame)
1795 gdb_assert (this_frame != NULL);
1797 /* Note that, due to the manner in which the sentinel frame is
1798 constructed, this_frame->next still works even when this_frame
1799 is the sentinel frame. But we disallow it here anyway because
1800 calling get_next_frame_sentinel_okay() on the sentinel frame
1801 is likely a coding error. */
1802 gdb_assert (this_frame != sentinel_frame);
1804 return this_frame->next;
1807 /* Observer for the target_changed event. */
1810 frame_observer_target_changed (struct target_ops *target)
1812 reinit_frame_cache ();
1815 /* Flush the entire frame cache. */
1818 reinit_frame_cache (void)
1820 struct frame_info *fi;
1822 /* Tear down all frame caches. */
1823 for (fi = sentinel_frame; fi != NULL; fi = fi->prev)
1825 if (fi->prologue_cache && fi->unwind->dealloc_cache)
1826 fi->unwind->dealloc_cache (fi, fi->prologue_cache);
1827 if (fi->base_cache && fi->base->unwind->dealloc_cache)
1828 fi->base->unwind->dealloc_cache (fi, fi->base_cache);
1831 /* Since we can't really be sure what the first object allocated was. */
1832 obstack_free (&frame_cache_obstack, 0);
1833 obstack_init (&frame_cache_obstack);
1835 if (sentinel_frame != NULL)
1836 annotate_frames_invalid ();
1838 sentinel_frame = NULL; /* Invalidate cache */
1839 select_frame (NULL);
1840 frame_stash_invalidate ();
1842 fprintf_unfiltered (gdb_stdlog, "{ reinit_frame_cache () }\n");
1845 /* Find where a register is saved (in memory or another register).
1846 The result of frame_register_unwind is just where it is saved
1847 relative to this particular frame. */
1850 frame_register_unwind_location (struct frame_info *this_frame, int regnum,
1851 int *optimizedp, enum lval_type *lvalp,
1852 CORE_ADDR *addrp, int *realnump)
1854 gdb_assert (this_frame == NULL || this_frame->level >= 0);
1856 while (this_frame != NULL)
1860 frame_register_unwind (this_frame, regnum, optimizedp, &unavailable,
1861 lvalp, addrp, realnump, NULL);
1866 if (*lvalp != lval_register)
1870 this_frame = get_next_frame (this_frame);
1874 /* Called during frame unwinding to remove a previous frame pointer from a
1875 frame passed in ARG. */
1878 remove_prev_frame (void *arg)
1880 struct frame_info *this_frame, *prev_frame;
1882 this_frame = (struct frame_info *) arg;
1883 prev_frame = this_frame->prev;
1884 gdb_assert (prev_frame != NULL);
1886 prev_frame->next = NULL;
1887 this_frame->prev = NULL;
1890 /* Get the previous raw frame, and check that it is not identical to
1891 same other frame frame already in the chain. If it is, there is
1892 most likely a stack cycle, so we discard it, and mark THIS_FRAME as
1893 outermost, with UNWIND_SAME_ID stop reason. Unlike the other
1894 validity tests, that compare THIS_FRAME and the next frame, we do
1895 this right after creating the previous frame, to avoid ever ending
1896 up with two frames with the same id in the frame chain. */
1898 static struct frame_info *
1899 get_prev_frame_if_no_cycle (struct frame_info *this_frame)
1901 struct frame_info *prev_frame;
1902 struct cleanup *prev_frame_cleanup;
1904 prev_frame = get_prev_frame_raw (this_frame);
1906 /* Don't compute the frame id of the current frame yet. Unwinding
1907 the sentinel frame can fail (e.g., if the thread is gone and we
1908 can't thus read its registers). If we let the cycle detection
1909 code below try to compute a frame ID, then an error thrown from
1910 within the frame ID computation would result in the sentinel
1911 frame as outermost frame, which is bogus. Instead, we'll compute
1912 the current frame's ID lazily in get_frame_id. Note that there's
1913 no point in doing cycle detection when there's only one frame, so
1914 nothing is lost here. */
1915 if (prev_frame->level == 0)
1918 /* The cleanup will remove the previous frame that get_prev_frame_raw
1919 linked onto THIS_FRAME. */
1920 prev_frame_cleanup = make_cleanup (remove_prev_frame, this_frame);
1922 compute_frame_id (prev_frame);
1923 if (!frame_stash_add (prev_frame))
1925 /* Another frame with the same id was already in the stash. We just
1926 detected a cycle. */
1929 fprintf_unfiltered (gdb_stdlog, "-> ");
1930 fprint_frame (gdb_stdlog, NULL);
1931 fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n");
1933 this_frame->stop_reason = UNWIND_SAME_ID;
1935 prev_frame->next = NULL;
1936 this_frame->prev = NULL;
1940 discard_cleanups (prev_frame_cleanup);
1944 /* Helper function for get_prev_frame_always, this is called inside a
1945 TRY_CATCH block. Return the frame that called THIS_FRAME or NULL if
1946 there is no such frame. This may throw an exception. */
1948 static struct frame_info *
1949 get_prev_frame_always_1 (struct frame_info *this_frame)
1951 struct gdbarch *gdbarch;
1953 gdb_assert (this_frame != NULL);
1954 gdbarch = get_frame_arch (this_frame);
1958 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame_always (this_frame=");
1959 if (this_frame != NULL)
1960 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
1962 fprintf_unfiltered (gdb_stdlog, "<NULL>");
1963 fprintf_unfiltered (gdb_stdlog, ") ");
1966 /* Only try to do the unwind once. */
1967 if (this_frame->prev_p)
1971 fprintf_unfiltered (gdb_stdlog, "-> ");
1972 fprint_frame (gdb_stdlog, this_frame->prev);
1973 fprintf_unfiltered (gdb_stdlog, " // cached \n");
1975 return this_frame->prev;
1978 /* If the frame unwinder hasn't been selected yet, we must do so
1979 before setting prev_p; otherwise the check for misbehaved
1980 sniffers will think that this frame's sniffer tried to unwind
1981 further (see frame_cleanup_after_sniffer). */
1982 if (this_frame->unwind == NULL)
1983 frame_unwind_find_by_frame (this_frame, &this_frame->prologue_cache);
1985 this_frame->prev_p = 1;
1986 this_frame->stop_reason = UNWIND_NO_REASON;
1988 /* If we are unwinding from an inline frame, all of the below tests
1989 were already performed when we unwound from the next non-inline
1990 frame. We must skip them, since we can not get THIS_FRAME's ID
1991 until we have unwound all the way down to the previous non-inline
1993 if (get_frame_type (this_frame) == INLINE_FRAME)
1994 return get_prev_frame_if_no_cycle (this_frame);
1996 /* Check that this frame is unwindable. If it isn't, don't try to
1997 unwind to the prev frame. */
1998 this_frame->stop_reason
1999 = this_frame->unwind->stop_reason (this_frame,
2000 &this_frame->prologue_cache);
2002 if (this_frame->stop_reason != UNWIND_NO_REASON)
2006 enum unwind_stop_reason reason = this_frame->stop_reason;
2008 fprintf_unfiltered (gdb_stdlog, "-> ");
2009 fprint_frame (gdb_stdlog, NULL);
2010 fprintf_unfiltered (gdb_stdlog, " // %s }\n",
2011 frame_stop_reason_symbol_string (reason));
2016 /* Check that this frame's ID isn't inner to (younger, below, next)
2017 the next frame. This happens when a frame unwind goes backwards.
2018 This check is valid only if this frame and the next frame are NORMAL.
2019 See the comment at frame_id_inner for details. */
2020 if (get_frame_type (this_frame) == NORMAL_FRAME
2021 && this_frame->next->unwind->type == NORMAL_FRAME
2022 && frame_id_inner (get_frame_arch (this_frame->next),
2023 get_frame_id (this_frame),
2024 get_frame_id (this_frame->next)))
2026 CORE_ADDR this_pc_in_block;
2027 struct minimal_symbol *morestack_msym;
2028 const char *morestack_name = NULL;
2030 /* gcc -fsplit-stack __morestack can continue the stack anywhere. */
2031 this_pc_in_block = get_frame_address_in_block (this_frame);
2032 morestack_msym = lookup_minimal_symbol_by_pc (this_pc_in_block).minsym;
2034 morestack_name = MSYMBOL_LINKAGE_NAME (morestack_msym);
2035 if (!morestack_name || strcmp (morestack_name, "__morestack") != 0)
2039 fprintf_unfiltered (gdb_stdlog, "-> ");
2040 fprint_frame (gdb_stdlog, NULL);
2041 fprintf_unfiltered (gdb_stdlog,
2042 " // this frame ID is inner }\n");
2044 this_frame->stop_reason = UNWIND_INNER_ID;
2049 /* Check that this and the next frame do not unwind the PC register
2050 to the same memory location. If they do, then even though they
2051 have different frame IDs, the new frame will be bogus; two
2052 functions can't share a register save slot for the PC. This can
2053 happen when the prologue analyzer finds a stack adjustment, but
2056 This check does assume that the "PC register" is roughly a
2057 traditional PC, even if the gdbarch_unwind_pc method adjusts
2058 it (we do not rely on the value, only on the unwound PC being
2059 dependent on this value). A potential improvement would be
2060 to have the frame prev_pc method and the gdbarch unwind_pc
2061 method set the same lval and location information as
2062 frame_register_unwind. */
2063 if (this_frame->level > 0
2064 && gdbarch_pc_regnum (gdbarch) >= 0
2065 && get_frame_type (this_frame) == NORMAL_FRAME
2066 && (get_frame_type (this_frame->next) == NORMAL_FRAME
2067 || get_frame_type (this_frame->next) == INLINE_FRAME))
2069 int optimized, realnum, nrealnum;
2070 enum lval_type lval, nlval;
2071 CORE_ADDR addr, naddr;
2073 frame_register_unwind_location (this_frame,
2074 gdbarch_pc_regnum (gdbarch),
2075 &optimized, &lval, &addr, &realnum);
2076 frame_register_unwind_location (get_next_frame (this_frame),
2077 gdbarch_pc_regnum (gdbarch),
2078 &optimized, &nlval, &naddr, &nrealnum);
2080 if ((lval == lval_memory && lval == nlval && addr == naddr)
2081 || (lval == lval_register && lval == nlval && realnum == nrealnum))
2085 fprintf_unfiltered (gdb_stdlog, "-> ");
2086 fprint_frame (gdb_stdlog, NULL);
2087 fprintf_unfiltered (gdb_stdlog, " // no saved PC }\n");
2090 this_frame->stop_reason = UNWIND_NO_SAVED_PC;
2091 this_frame->prev = NULL;
2096 return get_prev_frame_if_no_cycle (this_frame);
2099 /* Return a "struct frame_info" corresponding to the frame that called
2100 THIS_FRAME. Returns NULL if there is no such frame.
2102 Unlike get_prev_frame, this function always tries to unwind the
2106 get_prev_frame_always (struct frame_info *this_frame)
2108 struct frame_info *prev_frame = NULL;
2112 prev_frame = get_prev_frame_always_1 (this_frame);
2114 CATCH (ex, RETURN_MASK_ERROR)
2116 if (ex.error == MEMORY_ERROR)
2118 this_frame->stop_reason = UNWIND_MEMORY_ERROR;
2119 if (ex.message != NULL)
2124 /* The error needs to live as long as the frame does.
2125 Allocate using stack local STOP_STRING then assign the
2126 pointer to the frame, this allows the STOP_STRING on the
2127 frame to be of type 'const char *'. */
2128 size = strlen (ex.message) + 1;
2129 stop_string = (char *) frame_obstack_zalloc (size);
2130 memcpy (stop_string, ex.message, size);
2131 this_frame->stop_string = stop_string;
2136 throw_exception (ex);
2143 /* Construct a new "struct frame_info" and link it previous to
2146 static struct frame_info *
2147 get_prev_frame_raw (struct frame_info *this_frame)
2149 struct frame_info *prev_frame;
2151 /* Allocate the new frame but do not wire it in to the frame chain.
2152 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
2153 frame->next to pull some fancy tricks (of course such code is, by
2154 definition, recursive). Try to prevent it.
2156 There is no reason to worry about memory leaks, should the
2157 remainder of the function fail. The allocated memory will be
2158 quickly reclaimed when the frame cache is flushed, and the `we've
2159 been here before' check above will stop repeated memory
2160 allocation calls. */
2161 prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
2162 prev_frame->level = this_frame->level + 1;
2164 /* For now, assume we don't have frame chains crossing address
2166 prev_frame->pspace = this_frame->pspace;
2167 prev_frame->aspace = this_frame->aspace;
2169 /* Don't yet compute ->unwind (and hence ->type). It is computed
2170 on-demand in get_frame_type, frame_register_unwind, and
2173 /* Don't yet compute the frame's ID. It is computed on-demand by
2176 /* The unwound frame ID is validate at the start of this function,
2177 as part of the logic to decide if that frame should be further
2178 unwound, and not here while the prev frame is being created.
2179 Doing this makes it possible for the user to examine a frame that
2180 has an invalid frame ID.
2182 Some very old VAX code noted: [...] For the sake of argument,
2183 suppose that the stack is somewhat trashed (which is one reason
2184 that "info frame" exists). So, return 0 (indicating we don't
2185 know the address of the arglist) if we don't know what frame this
2189 this_frame->prev = prev_frame;
2190 prev_frame->next = this_frame;
2194 fprintf_unfiltered (gdb_stdlog, "-> ");
2195 fprint_frame (gdb_stdlog, prev_frame);
2196 fprintf_unfiltered (gdb_stdlog, " }\n");
2202 /* Debug routine to print a NULL frame being returned. */
2205 frame_debug_got_null_frame (struct frame_info *this_frame,
2210 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame (this_frame=");
2211 if (this_frame != NULL)
2212 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
2214 fprintf_unfiltered (gdb_stdlog, "<NULL>");
2215 fprintf_unfiltered (gdb_stdlog, ") -> // %s}\n", reason);
2219 /* Is this (non-sentinel) frame in the "main"() function? */
2222 inside_main_func (struct frame_info *this_frame)
2224 struct bound_minimal_symbol msymbol;
2227 if (symfile_objfile == 0)
2229 msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
2230 if (msymbol.minsym == NULL)
2232 /* Make certain that the code, and not descriptor, address is
2234 maddr = gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame),
2235 BMSYMBOL_VALUE_ADDRESS (msymbol),
2237 return maddr == get_frame_func (this_frame);
2240 /* Test whether THIS_FRAME is inside the process entry point function. */
2243 inside_entry_func (struct frame_info *this_frame)
2245 CORE_ADDR entry_point;
2247 if (!entry_point_address_query (&entry_point))
2250 return get_frame_func (this_frame) == entry_point;
2253 /* Return a structure containing various interesting information about
2254 the frame that called THIS_FRAME. Returns NULL if there is entier
2255 no such frame or the frame fails any of a set of target-independent
2256 condition that should terminate the frame chain (e.g., as unwinding
2259 This function should not contain target-dependent tests, such as
2260 checking whether the program-counter is zero. */
2263 get_prev_frame (struct frame_info *this_frame)
2268 /* There is always a frame. If this assertion fails, suspect that
2269 something should be calling get_selected_frame() or
2270 get_current_frame(). */
2271 gdb_assert (this_frame != NULL);
2273 /* If this_frame is the current frame, then compute and stash
2274 its frame id prior to fetching and computing the frame id of the
2275 previous frame. Otherwise, the cycle detection code in
2276 get_prev_frame_if_no_cycle() will not work correctly. When
2277 get_frame_id() is called later on, an assertion error will
2278 be triggered in the event of a cycle between the current
2279 frame and its previous frame. */
2280 if (this_frame->level == 0)
2281 get_frame_id (this_frame);
2283 frame_pc_p = get_frame_pc_if_available (this_frame, &frame_pc);
2285 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
2286 sense to stop unwinding at a dummy frame. One place where a dummy
2287 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
2288 pcsqh register (space register for the instruction at the head of the
2289 instruction queue) cannot be written directly; the only way to set it
2290 is to branch to code that is in the target space. In order to implement
2291 frame dummies on HPUX, the called function is made to jump back to where
2292 the inferior was when the user function was called. If gdb was inside
2293 the main function when we created the dummy frame, the dummy frame will
2294 point inside the main function. */
2295 if (this_frame->level >= 0
2296 && get_frame_type (this_frame) == NORMAL_FRAME
2297 && !backtrace_past_main
2299 && inside_main_func (this_frame))
2300 /* Don't unwind past main(). Note, this is done _before_ the
2301 frame has been marked as previously unwound. That way if the
2302 user later decides to enable unwinds past main(), that will
2303 automatically happen. */
2305 frame_debug_got_null_frame (this_frame, "inside main func");
2309 /* If the user's backtrace limit has been exceeded, stop. We must
2310 add two to the current level; one of those accounts for backtrace_limit
2311 being 1-based and the level being 0-based, and the other accounts for
2312 the level of the new frame instead of the level of the current
2314 if (this_frame->level + 2 > backtrace_limit)
2316 frame_debug_got_null_frame (this_frame, "backtrace limit exceeded");
2320 /* If we're already inside the entry function for the main objfile,
2321 then it isn't valid. Don't apply this test to a dummy frame -
2322 dummy frame PCs typically land in the entry func. Don't apply
2323 this test to the sentinel frame. Sentinel frames should always
2324 be allowed to unwind. */
2325 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
2326 wasn't checking for "main" in the minimal symbols. With that
2327 fixed asm-source tests now stop in "main" instead of halting the
2328 backtrace in weird and wonderful ways somewhere inside the entry
2329 file. Suspect that tests for inside the entry file/func were
2330 added to work around that (now fixed) case. */
2331 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
2332 suggested having the inside_entry_func test use the
2333 inside_main_func() msymbol trick (along with entry_point_address()
2334 I guess) to determine the address range of the start function.
2335 That should provide a far better stopper than the current
2337 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
2338 applied tail-call optimizations to main so that a function called
2339 from main returns directly to the caller of main. Since we don't
2340 stop at main, we should at least stop at the entry point of the
2342 if (this_frame->level >= 0
2343 && get_frame_type (this_frame) == NORMAL_FRAME
2344 && !backtrace_past_entry
2346 && inside_entry_func (this_frame))
2348 frame_debug_got_null_frame (this_frame, "inside entry func");
2352 /* Assume that the only way to get a zero PC is through something
2353 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
2354 will never unwind a zero PC. */
2355 if (this_frame->level > 0
2356 && (get_frame_type (this_frame) == NORMAL_FRAME
2357 || get_frame_type (this_frame) == INLINE_FRAME)
2358 && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME
2359 && frame_pc_p && frame_pc == 0)
2361 frame_debug_got_null_frame (this_frame, "zero PC");
2365 return get_prev_frame_always (this_frame);
2369 get_prev_frame_id_by_id (struct frame_id id)
2371 struct frame_id prev_id;
2372 struct frame_info *frame;
2374 frame = frame_find_by_id (id);
2377 prev_id = get_frame_id (get_prev_frame (frame));
2379 prev_id = null_frame_id;
2385 get_frame_pc (struct frame_info *frame)
2387 gdb_assert (frame->next != NULL);
2388 return frame_unwind_pc (frame->next);
2392 get_frame_pc_if_available (struct frame_info *frame, CORE_ADDR *pc)
2395 gdb_assert (frame->next != NULL);
2399 *pc = frame_unwind_pc (frame->next);
2401 CATCH (ex, RETURN_MASK_ERROR)
2403 if (ex.error == NOT_AVAILABLE_ERROR)
2406 throw_exception (ex);
2413 /* Return an address that falls within THIS_FRAME's code block. */
2416 get_frame_address_in_block (struct frame_info *this_frame)
2418 /* A draft address. */
2419 CORE_ADDR pc = get_frame_pc (this_frame);
2421 struct frame_info *next_frame = this_frame->next;
2423 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
2424 Normally the resume address is inside the body of the function
2425 associated with THIS_FRAME, but there is a special case: when
2426 calling a function which the compiler knows will never return
2427 (for instance abort), the call may be the very last instruction
2428 in the calling function. The resume address will point after the
2429 call and may be at the beginning of a different function
2432 If THIS_FRAME is a signal frame or dummy frame, then we should
2433 not adjust the unwound PC. For a dummy frame, GDB pushed the
2434 resume address manually onto the stack. For a signal frame, the
2435 OS may have pushed the resume address manually and invoked the
2436 handler (e.g. GNU/Linux), or invoked the trampoline which called
2437 the signal handler - but in either case the signal handler is
2438 expected to return to the trampoline. So in both of these
2439 cases we know that the resume address is executable and
2440 related. So we only need to adjust the PC if THIS_FRAME
2441 is a normal function.
2443 If the program has been interrupted while THIS_FRAME is current,
2444 then clearly the resume address is inside the associated
2445 function. There are three kinds of interruption: debugger stop
2446 (next frame will be SENTINEL_FRAME), operating system
2447 signal or exception (next frame will be SIGTRAMP_FRAME),
2448 or debugger-induced function call (next frame will be
2449 DUMMY_FRAME). So we only need to adjust the PC if
2450 NEXT_FRAME is a normal function.
2452 We check the type of NEXT_FRAME first, since it is already
2453 known; frame type is determined by the unwinder, and since
2454 we have THIS_FRAME we've already selected an unwinder for
2457 If the next frame is inlined, we need to keep going until we find
2458 the real function - for instance, if a signal handler is invoked
2459 while in an inlined function, then the code address of the
2460 "calling" normal function should not be adjusted either. */
2462 while (get_frame_type (next_frame) == INLINE_FRAME)
2463 next_frame = next_frame->next;
2465 if ((get_frame_type (next_frame) == NORMAL_FRAME
2466 || get_frame_type (next_frame) == TAILCALL_FRAME)
2467 && (get_frame_type (this_frame) == NORMAL_FRAME
2468 || get_frame_type (this_frame) == TAILCALL_FRAME
2469 || get_frame_type (this_frame) == INLINE_FRAME))
2476 get_frame_address_in_block_if_available (struct frame_info *this_frame,
2482 *pc = get_frame_address_in_block (this_frame);
2484 CATCH (ex, RETURN_MASK_ERROR)
2486 if (ex.error == NOT_AVAILABLE_ERROR)
2488 throw_exception (ex);
2496 find_frame_sal (frame_info *frame)
2498 struct frame_info *next_frame;
2502 /* If the next frame represents an inlined function call, this frame's
2503 sal is the "call site" of that inlined function, which can not
2504 be inferred from get_frame_pc. */
2505 next_frame = get_next_frame (frame);
2506 if (frame_inlined_callees (frame) > 0)
2511 sym = get_frame_function (next_frame);
2513 sym = inline_skipped_symbol (inferior_ptid);
2515 /* If frame is inline, it certainly has symbols. */
2518 symtab_and_line sal;
2519 if (SYMBOL_LINE (sym) != 0)
2521 sal.symtab = symbol_symtab (sym);
2522 sal.line = SYMBOL_LINE (sym);
2525 /* If the symbol does not have a location, we don't know where
2526 the call site is. Do not pretend to. This is jarring, but
2527 we can't do much better. */
2528 sal.pc = get_frame_pc (frame);
2530 sal.pspace = get_frame_program_space (frame);
2534 /* If FRAME is not the innermost frame, that normally means that
2535 FRAME->pc points at the return instruction (which is *after* the
2536 call instruction), and we want to get the line containing the
2537 call (because the call is where the user thinks the program is).
2538 However, if the next frame is either a SIGTRAMP_FRAME or a
2539 DUMMY_FRAME, then the next frame will contain a saved interrupt
2540 PC and such a PC indicates the current (rather than next)
2541 instruction/line, consequently, for such cases, want to get the
2542 line containing fi->pc. */
2543 if (!get_frame_pc_if_available (frame, &pc))
2546 notcurrent = (pc != get_frame_address_in_block (frame));
2547 return find_pc_line (pc, notcurrent);
2550 /* Per "frame.h", return the ``address'' of the frame. Code should
2551 really be using get_frame_id(). */
2553 get_frame_base (struct frame_info *fi)
2555 return get_frame_id (fi).stack_addr;
2558 /* High-level offsets into the frame. Used by the debug info. */
2561 get_frame_base_address (struct frame_info *fi)
2563 if (get_frame_type (fi) != NORMAL_FRAME)
2565 if (fi->base == NULL)
2566 fi->base = frame_base_find_by_frame (fi);
2567 /* Sneaky: If the low-level unwind and high-level base code share a
2568 common unwinder, let them share the prologue cache. */
2569 if (fi->base->unwind == fi->unwind)
2570 return fi->base->this_base (fi, &fi->prologue_cache);
2571 return fi->base->this_base (fi, &fi->base_cache);
2575 get_frame_locals_address (struct frame_info *fi)
2577 if (get_frame_type (fi) != NORMAL_FRAME)
2579 /* If there isn't a frame address method, find it. */
2580 if (fi->base == NULL)
2581 fi->base = frame_base_find_by_frame (fi);
2582 /* Sneaky: If the low-level unwind and high-level base code share a
2583 common unwinder, let them share the prologue cache. */
2584 if (fi->base->unwind == fi->unwind)
2585 return fi->base->this_locals (fi, &fi->prologue_cache);
2586 return fi->base->this_locals (fi, &fi->base_cache);
2590 get_frame_args_address (struct frame_info *fi)
2592 if (get_frame_type (fi) != NORMAL_FRAME)
2594 /* If there isn't a frame address method, find it. */
2595 if (fi->base == NULL)
2596 fi->base = frame_base_find_by_frame (fi);
2597 /* Sneaky: If the low-level unwind and high-level base code share a
2598 common unwinder, let them share the prologue cache. */
2599 if (fi->base->unwind == fi->unwind)
2600 return fi->base->this_args (fi, &fi->prologue_cache);
2601 return fi->base->this_args (fi, &fi->base_cache);
2604 /* Return true if the frame unwinder for frame FI is UNWINDER; false
2608 frame_unwinder_is (struct frame_info *fi, const struct frame_unwind *unwinder)
2610 if (fi->unwind == NULL)
2611 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
2612 return fi->unwind == unwinder;
2615 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
2616 or -1 for a NULL frame. */
2619 frame_relative_level (struct frame_info *fi)
2628 get_frame_type (struct frame_info *frame)
2630 if (frame->unwind == NULL)
2631 /* Initialize the frame's unwinder because that's what
2632 provides the frame's type. */
2633 frame_unwind_find_by_frame (frame, &frame->prologue_cache);
2634 return frame->unwind->type;
2637 struct program_space *
2638 get_frame_program_space (struct frame_info *frame)
2640 return frame->pspace;
2643 struct program_space *
2644 frame_unwind_program_space (struct frame_info *this_frame)
2646 gdb_assert (this_frame);
2648 /* This is really a placeholder to keep the API consistent --- we
2649 assume for now that we don't have frame chains crossing
2651 return this_frame->pspace;
2654 const address_space *
2655 get_frame_address_space (struct frame_info *frame)
2657 return frame->aspace;
2660 /* Memory access methods. */
2663 get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr,
2664 gdb_byte *buf, int len)
2666 read_memory (addr, buf, len);
2670 get_frame_memory_signed (struct frame_info *this_frame, CORE_ADDR addr,
2673 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2674 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2676 return read_memory_integer (addr, len, byte_order);
2680 get_frame_memory_unsigned (struct frame_info *this_frame, CORE_ADDR addr,
2683 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2684 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2686 return read_memory_unsigned_integer (addr, len, byte_order);
2690 safe_frame_unwind_memory (struct frame_info *this_frame,
2691 CORE_ADDR addr, gdb_byte *buf, int len)
2693 /* NOTE: target_read_memory returns zero on success! */
2694 return !target_read_memory (addr, buf, len);
2697 /* Architecture methods. */
2700 get_frame_arch (struct frame_info *this_frame)
2702 return frame_unwind_arch (this_frame->next);
2706 frame_unwind_arch (struct frame_info *next_frame)
2708 if (!next_frame->prev_arch.p)
2710 struct gdbarch *arch;
2712 if (next_frame->unwind == NULL)
2713 frame_unwind_find_by_frame (next_frame, &next_frame->prologue_cache);
2715 if (next_frame->unwind->prev_arch != NULL)
2716 arch = next_frame->unwind->prev_arch (next_frame,
2717 &next_frame->prologue_cache);
2719 arch = get_frame_arch (next_frame);
2721 next_frame->prev_arch.arch = arch;
2722 next_frame->prev_arch.p = 1;
2724 fprintf_unfiltered (gdb_stdlog,
2725 "{ frame_unwind_arch (next_frame=%d) -> %s }\n",
2727 gdbarch_bfd_arch_info (arch)->printable_name);
2730 return next_frame->prev_arch.arch;
2734 frame_unwind_caller_arch (struct frame_info *next_frame)
2736 next_frame = skip_artificial_frames (next_frame);
2738 /* We must have a non-artificial frame. The caller is supposed to check
2739 the result of frame_unwind_caller_id (), which returns NULL_FRAME_ID
2741 gdb_assert (next_frame != NULL);
2743 return frame_unwind_arch (next_frame);
2746 /* Gets the language of FRAME. */
2749 get_frame_language (struct frame_info *frame)
2754 gdb_assert (frame!= NULL);
2756 /* We determine the current frame language by looking up its
2757 associated symtab. To retrieve this symtab, we use the frame
2758 PC. However we cannot use the frame PC as is, because it
2759 usually points to the instruction following the "call", which
2760 is sometimes the first instruction of another function. So
2761 we rely on get_frame_address_in_block(), it provides us with
2762 a PC that is guaranteed to be inside the frame's code
2767 pc = get_frame_address_in_block (frame);
2770 CATCH (ex, RETURN_MASK_ERROR)
2772 if (ex.error != NOT_AVAILABLE_ERROR)
2773 throw_exception (ex);
2779 struct compunit_symtab *cust = find_pc_compunit_symtab (pc);
2782 return compunit_language (cust);
2785 return language_unknown;
2788 /* Stack pointer methods. */
2791 get_frame_sp (struct frame_info *this_frame)
2793 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2795 /* Normality - an architecture that provides a way of obtaining any
2796 frame inner-most address. */
2797 if (gdbarch_unwind_sp_p (gdbarch))
2798 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
2799 operate on THIS_FRAME now. */
2800 return gdbarch_unwind_sp (gdbarch, this_frame->next);
2801 /* Now things are really are grim. Hope that the value returned by
2802 the gdbarch_sp_regnum register is meaningful. */
2803 if (gdbarch_sp_regnum (gdbarch) >= 0)
2804 return get_frame_register_unsigned (this_frame,
2805 gdbarch_sp_regnum (gdbarch));
2806 internal_error (__FILE__, __LINE__, _("Missing unwind SP method"));
2809 /* Return the reason why we can't unwind past FRAME. */
2811 enum unwind_stop_reason
2812 get_frame_unwind_stop_reason (struct frame_info *frame)
2814 /* Fill-in STOP_REASON. */
2815 get_prev_frame_always (frame);
2816 gdb_assert (frame->prev_p);
2818 return frame->stop_reason;
2821 /* Return a string explaining REASON. */
2824 unwind_stop_reason_to_string (enum unwind_stop_reason reason)
2828 #define SET(name, description) \
2829 case name: return _(description);
2830 #include "unwind_stop_reasons.def"
2834 internal_error (__FILE__, __LINE__,
2835 "Invalid frame stop reason");
2840 frame_stop_reason_string (struct frame_info *fi)
2842 gdb_assert (fi->prev_p);
2843 gdb_assert (fi->prev == NULL);
2845 /* Return the specific string if we have one. */
2846 if (fi->stop_string != NULL)
2847 return fi->stop_string;
2849 /* Return the generic string if we have nothing better. */
2850 return unwind_stop_reason_to_string (fi->stop_reason);
2853 /* Return the enum symbol name of REASON as a string, to use in debug
2857 frame_stop_reason_symbol_string (enum unwind_stop_reason reason)
2861 #define SET(name, description) \
2862 case name: return #name;
2863 #include "unwind_stop_reasons.def"
2867 internal_error (__FILE__, __LINE__,
2868 "Invalid frame stop reason");
2872 /* Clean up after a failed (wrong unwinder) attempt to unwind past
2876 frame_cleanup_after_sniffer (struct frame_info *frame)
2878 /* The sniffer should not allocate a prologue cache if it did not
2879 match this frame. */
2880 gdb_assert (frame->prologue_cache == NULL);
2882 /* No sniffer should extend the frame chain; sniff based on what is
2884 gdb_assert (!frame->prev_p);
2886 /* The sniffer should not check the frame's ID; that's circular. */
2887 gdb_assert (!frame->this_id.p);
2889 /* Clear cached fields dependent on the unwinder.
2891 The previous PC is independent of the unwinder, but the previous
2892 function is not (see get_frame_address_in_block). */
2893 frame->prev_func.p = 0;
2894 frame->prev_func.addr = 0;
2896 /* Discard the unwinder last, so that we can easily find it if an assertion
2897 in this function triggers. */
2898 frame->unwind = NULL;
2901 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
2902 If sniffing fails, the caller should be sure to call
2903 frame_cleanup_after_sniffer. */
2906 frame_prepare_for_sniffer (struct frame_info *frame,
2907 const struct frame_unwind *unwind)
2909 gdb_assert (frame->unwind == NULL);
2910 frame->unwind = unwind;
2913 static struct cmd_list_element *set_backtrace_cmdlist;
2914 static struct cmd_list_element *show_backtrace_cmdlist;
2917 set_backtrace_cmd (const char *args, int from_tty)
2919 help_list (set_backtrace_cmdlist, "set backtrace ", all_commands,
2924 show_backtrace_cmd (const char *args, int from_tty)
2926 cmd_show_list (show_backtrace_cmdlist, from_tty, "");
2930 _initialize_frame (void)
2932 obstack_init (&frame_cache_obstack);
2934 frame_stash_create ();
2936 gdb::observers::target_changed.attach (frame_observer_target_changed);
2938 add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, _("\
2939 Set backtrace specific variables.\n\
2940 Configure backtrace variables such as the backtrace limit"),
2941 &set_backtrace_cmdlist, "set backtrace ",
2942 0/*allow-unknown*/, &setlist);
2943 add_prefix_cmd ("backtrace", class_maintenance, show_backtrace_cmd, _("\
2944 Show backtrace specific variables\n\
2945 Show backtrace variables such as the backtrace limit"),
2946 &show_backtrace_cmdlist, "show backtrace ",
2947 0/*allow-unknown*/, &showlist);
2949 add_setshow_boolean_cmd ("past-main", class_obscure,
2950 &backtrace_past_main, _("\
2951 Set whether backtraces should continue past \"main\"."), _("\
2952 Show whether backtraces should continue past \"main\"."), _("\
2953 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
2954 the backtrace at \"main\". Set this variable if you need to see the rest\n\
2955 of the stack trace."),
2957 show_backtrace_past_main,
2958 &set_backtrace_cmdlist,
2959 &show_backtrace_cmdlist);
2961 add_setshow_boolean_cmd ("past-entry", class_obscure,
2962 &backtrace_past_entry, _("\
2963 Set whether backtraces should continue past the entry point of a program."),
2965 Show whether backtraces should continue past the entry point of a program."),
2967 Normally there are no callers beyond the entry point of a program, so GDB\n\
2968 will terminate the backtrace there. Set this variable if you need to see\n\
2969 the rest of the stack trace."),
2971 show_backtrace_past_entry,
2972 &set_backtrace_cmdlist,
2973 &show_backtrace_cmdlist);
2975 add_setshow_uinteger_cmd ("limit", class_obscure,
2976 &backtrace_limit, _("\
2977 Set an upper bound on the number of backtrace levels."), _("\
2978 Show the upper bound on the number of backtrace levels."), _("\
2979 No more than the specified number of frames can be displayed or examined.\n\
2980 Literal \"unlimited\" or zero means no limit."),
2982 show_backtrace_limit,
2983 &set_backtrace_cmdlist,
2984 &show_backtrace_cmdlist);
2986 /* Debug this files internals. */
2987 add_setshow_zuinteger_cmd ("frame", class_maintenance, &frame_debug, _("\
2988 Set frame debugging."), _("\
2989 Show frame debugging."), _("\
2990 When non-zero, frame specific internal debugging is enabled."),
2993 &setdebuglist, &showdebuglist);