1 /* Cache and manage frames for GDB, the GNU debugger.
3 Copyright (C) 1986-1987, 1989, 1991, 1994-1996, 1998, 2000-2004,
4 2007-2012 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
25 #include "inferior.h" /* for inferior_ptid */
27 #include "gdb_assert.h"
28 #include "gdb_string.h"
29 #include "user-regs.h"
30 #include "gdb_obstack.h"
31 #include "dummy-frame.h"
32 #include "sentinel-frame.h"
36 #include "frame-unwind.h"
37 #include "frame-base.h"
42 #include "exceptions.h"
43 #include "gdbthread.h"
45 #include "inline-frame.h"
46 #include "tracepoint.h"
48 static struct frame_info *get_prev_frame_1 (struct frame_info *this_frame);
49 static struct frame_info *get_prev_frame_raw (struct frame_info *this_frame);
51 /* We keep a cache of stack frames, each of which is a "struct
52 frame_info". The innermost one gets allocated (in
53 wait_for_inferior) each time the inferior stops; current_frame
54 points to it. Additional frames get allocated (in get_prev_frame)
55 as needed, and are chained through the next and prev fields. Any
56 time that the frame cache becomes invalid (most notably when we
57 execute something, but also if we change how we interpret the
58 frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything
59 which reads new symbols)), we should call reinit_frame_cache. */
63 /* Level of this frame. The inner-most (youngest) frame is at level
64 0. As you move towards the outer-most (oldest) frame, the level
65 increases. This is a cached value. It could just as easily be
66 computed by counting back from the selected frame to the inner
68 /* NOTE: cagney/2002-04-05: Perhaps a level of ``-1'' should be
69 reserved to indicate a bogus frame - one that has been created
70 just to keep GDB happy (GDB always needs a frame). For the
71 moment leave this as speculation. */
74 /* The frame's program space. */
75 struct program_space *pspace;
77 /* The frame's address space. */
78 struct address_space *aspace;
80 /* The frame's low-level unwinder and corresponding cache. The
81 low-level unwinder is responsible for unwinding register values
82 for the previous frame. The low-level unwind methods are
83 selected based on the presence, or otherwise, of register unwind
84 information such as CFI. */
86 const struct frame_unwind *unwind;
88 /* Cached copy of the previous frame's architecture. */
95 /* Cached copy of the previous frame's resume address. */
101 /* Cached copy of the previous frame's function address. */
108 /* This frame's ID. */
112 struct frame_id value;
115 /* The frame's high-level base methods, and corresponding cache.
116 The high level base methods are selected based on the frame's
118 const struct frame_base *base;
121 /* Pointers to the next (down, inner, younger) and previous (up,
122 outer, older) frame_info's in the frame cache. */
123 struct frame_info *next; /* down, inner, younger */
125 struct frame_info *prev; /* up, outer, older */
127 /* The reason why we could not set PREV, or UNWIND_NO_REASON if we
128 could. Only valid when PREV_P is set. */
129 enum unwind_stop_reason stop_reason;
132 /* A frame stash used to speed up frame lookups. */
134 /* We currently only stash one frame at a time, as this seems to be
135 sufficient for now. */
136 static struct frame_info *frame_stash = NULL;
138 /* Add the following FRAME to the frame stash. */
141 frame_stash_add (struct frame_info *frame)
146 /* Search the frame stash for an entry with the given frame ID.
147 If found, return that frame. Otherwise return NULL. */
149 static struct frame_info *
150 frame_stash_find (struct frame_id id)
152 if (frame_stash && frame_id_eq (frame_stash->this_id.value, id))
158 /* Invalidate the frame stash by removing all entries in it. */
161 frame_stash_invalidate (void)
166 /* Flag to control debugging. */
168 unsigned int frame_debug;
170 show_frame_debug (struct ui_file *file, int from_tty,
171 struct cmd_list_element *c, const char *value)
173 fprintf_filtered (file, _("Frame debugging is %s.\n"), value);
176 /* Flag to indicate whether backtraces should stop at main et.al. */
178 static int backtrace_past_main;
180 show_backtrace_past_main (struct ui_file *file, int from_tty,
181 struct cmd_list_element *c, const char *value)
183 fprintf_filtered (file,
184 _("Whether backtraces should "
185 "continue past \"main\" is %s.\n"),
189 static int backtrace_past_entry;
191 show_backtrace_past_entry (struct ui_file *file, int from_tty,
192 struct cmd_list_element *c, const char *value)
194 fprintf_filtered (file, _("Whether backtraces should continue past the "
195 "entry point of a program is %s.\n"),
199 static unsigned int backtrace_limit = UINT_MAX;
201 show_backtrace_limit (struct ui_file *file, int from_tty,
202 struct cmd_list_element *c, const char *value)
204 fprintf_filtered (file,
205 _("An upper bound on the number "
206 "of backtrace levels is %s.\n"),
212 fprint_field (struct ui_file *file, const char *name, int p, CORE_ADDR addr)
215 fprintf_unfiltered (file, "%s=%s", name, hex_string (addr));
217 fprintf_unfiltered (file, "!%s", name);
221 fprint_frame_id (struct ui_file *file, struct frame_id id)
223 fprintf_unfiltered (file, "{");
224 fprint_field (file, "stack", id.stack_addr_p, id.stack_addr);
225 fprintf_unfiltered (file, ",");
226 fprint_field (file, "code", id.code_addr_p, id.code_addr);
227 fprintf_unfiltered (file, ",");
228 fprint_field (file, "special", id.special_addr_p, id.special_addr);
229 if (id.artificial_depth)
230 fprintf_unfiltered (file, ",artificial=%d", id.artificial_depth);
231 fprintf_unfiltered (file, "}");
235 fprint_frame_type (struct ui_file *file, enum frame_type type)
240 fprintf_unfiltered (file, "NORMAL_FRAME");
243 fprintf_unfiltered (file, "DUMMY_FRAME");
246 fprintf_unfiltered (file, "INLINE_FRAME");
249 fprintf_unfiltered (file, "SENTINEL_FRAME");
252 fprintf_unfiltered (file, "SIGTRAMP_FRAME");
255 fprintf_unfiltered (file, "ARCH_FRAME");
258 fprintf_unfiltered (file, "<unknown type>");
264 fprint_frame (struct ui_file *file, struct frame_info *fi)
268 fprintf_unfiltered (file, "<NULL frame>");
271 fprintf_unfiltered (file, "{");
272 fprintf_unfiltered (file, "level=%d", fi->level);
273 fprintf_unfiltered (file, ",");
274 fprintf_unfiltered (file, "type=");
275 if (fi->unwind != NULL)
276 fprint_frame_type (file, fi->unwind->type);
278 fprintf_unfiltered (file, "<unknown>");
279 fprintf_unfiltered (file, ",");
280 fprintf_unfiltered (file, "unwind=");
281 if (fi->unwind != NULL)
282 gdb_print_host_address (fi->unwind, file);
284 fprintf_unfiltered (file, "<unknown>");
285 fprintf_unfiltered (file, ",");
286 fprintf_unfiltered (file, "pc=");
287 if (fi->next != NULL && fi->next->prev_pc.p)
288 fprintf_unfiltered (file, "%s", hex_string (fi->next->prev_pc.value));
290 fprintf_unfiltered (file, "<unknown>");
291 fprintf_unfiltered (file, ",");
292 fprintf_unfiltered (file, "id=");
294 fprint_frame_id (file, fi->this_id.value);
296 fprintf_unfiltered (file, "<unknown>");
297 fprintf_unfiltered (file, ",");
298 fprintf_unfiltered (file, "func=");
299 if (fi->next != NULL && fi->next->prev_func.p)
300 fprintf_unfiltered (file, "%s", hex_string (fi->next->prev_func.addr));
302 fprintf_unfiltered (file, "<unknown>");
303 fprintf_unfiltered (file, "}");
306 /* Given FRAME, return the enclosing frame as found in real frames read-in from
307 inferior memory. Skip any previous frames which were made up by GDB.
308 Return the original frame if no immediate previous frames exist. */
310 static struct frame_info *
311 skip_artificial_frames (struct frame_info *frame)
313 while (get_frame_type (frame) == INLINE_FRAME
314 || get_frame_type (frame) == TAILCALL_FRAME)
315 frame = get_prev_frame (frame);
320 /* Return a frame uniq ID that can be used to, later, re-find the
324 get_frame_id (struct frame_info *fi)
327 return null_frame_id;
332 fprintf_unfiltered (gdb_stdlog, "{ get_frame_id (fi=%d) ",
334 /* Find the unwinder. */
335 if (fi->unwind == NULL)
336 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
337 /* Find THIS frame's ID. */
338 /* Default to outermost if no ID is found. */
339 fi->this_id.value = outer_frame_id;
340 fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value);
341 gdb_assert (frame_id_p (fi->this_id.value));
345 fprintf_unfiltered (gdb_stdlog, "-> ");
346 fprint_frame_id (gdb_stdlog, fi->this_id.value);
347 fprintf_unfiltered (gdb_stdlog, " }\n");
351 frame_stash_add (fi);
353 return fi->this_id.value;
357 get_stack_frame_id (struct frame_info *next_frame)
359 return get_frame_id (skip_artificial_frames (next_frame));
363 frame_unwind_caller_id (struct frame_info *next_frame)
365 struct frame_info *this_frame;
367 /* Use get_prev_frame_1, and not get_prev_frame. The latter will truncate
368 the frame chain, leading to this function unintentionally
369 returning a null_frame_id (e.g., when a caller requests the frame
370 ID of "main()"s caller. */
372 next_frame = skip_artificial_frames (next_frame);
373 this_frame = get_prev_frame_1 (next_frame);
375 return get_frame_id (skip_artificial_frames (this_frame));
377 return null_frame_id;
380 const struct frame_id null_frame_id; /* All zeros. */
381 const struct frame_id outer_frame_id = { 0, 0, 0, 0, 0, 1, 0 };
384 frame_id_build_special (CORE_ADDR stack_addr, CORE_ADDR code_addr,
385 CORE_ADDR special_addr)
387 struct frame_id id = null_frame_id;
389 id.stack_addr = stack_addr;
391 id.code_addr = code_addr;
393 id.special_addr = special_addr;
394 id.special_addr_p = 1;
399 frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr)
401 struct frame_id id = null_frame_id;
403 id.stack_addr = stack_addr;
405 id.code_addr = code_addr;
411 frame_id_build_wild (CORE_ADDR stack_addr)
413 struct frame_id id = null_frame_id;
415 id.stack_addr = stack_addr;
421 frame_id_p (struct frame_id l)
425 /* The frame is valid iff it has a valid stack address. */
427 /* outer_frame_id is also valid. */
428 if (!p && memcmp (&l, &outer_frame_id, sizeof (l)) == 0)
432 fprintf_unfiltered (gdb_stdlog, "{ frame_id_p (l=");
433 fprint_frame_id (gdb_stdlog, l);
434 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", p);
440 frame_id_artificial_p (struct frame_id l)
445 return (l.artificial_depth != 0);
449 frame_id_eq (struct frame_id l, struct frame_id r)
453 if (!l.stack_addr_p && l.special_addr_p
454 && !r.stack_addr_p && r.special_addr_p)
455 /* The outermost frame marker is equal to itself. This is the
456 dodgy thing about outer_frame_id, since between execution steps
457 we might step into another function - from which we can't
458 unwind either. More thought required to get rid of
461 else if (!l.stack_addr_p || !r.stack_addr_p)
462 /* Like a NaN, if either ID is invalid, the result is false.
463 Note that a frame ID is invalid iff it is the null frame ID. */
465 else if (l.stack_addr != r.stack_addr)
466 /* If .stack addresses are different, the frames are different. */
468 else if (l.code_addr_p && r.code_addr_p && l.code_addr != r.code_addr)
469 /* An invalid code addr is a wild card. If .code addresses are
470 different, the frames are different. */
472 else if (l.special_addr_p && r.special_addr_p
473 && l.special_addr != r.special_addr)
474 /* An invalid special addr is a wild card (or unused). Otherwise
475 if special addresses are different, the frames are different. */
477 else if (l.artificial_depth != r.artificial_depth)
478 /* If artifical depths are different, the frames must be different. */
481 /* Frames are equal. */
486 fprintf_unfiltered (gdb_stdlog, "{ frame_id_eq (l=");
487 fprint_frame_id (gdb_stdlog, l);
488 fprintf_unfiltered (gdb_stdlog, ",r=");
489 fprint_frame_id (gdb_stdlog, r);
490 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", eq);
495 /* Safety net to check whether frame ID L should be inner to
496 frame ID R, according to their stack addresses.
498 This method cannot be used to compare arbitrary frames, as the
499 ranges of valid stack addresses may be discontiguous (e.g. due
502 However, it can be used as safety net to discover invalid frame
503 IDs in certain circumstances. Assuming that NEXT is the immediate
504 inner frame to THIS and that NEXT and THIS are both NORMAL frames:
506 * The stack address of NEXT must be inner-than-or-equal to the stack
509 Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind
512 * If NEXT and THIS have different stack addresses, no other frame
513 in the frame chain may have a stack address in between.
515 Therefore, if frame_id_inner (TEST, THIS) holds, but
516 frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer
517 to a valid frame in the frame chain.
519 The sanity checks above cannot be performed when a SIGTRAMP frame
520 is involved, because signal handlers might be executed on a different
521 stack than the stack used by the routine that caused the signal
522 to be raised. This can happen for instance when a thread exceeds
523 its maximum stack size. In this case, certain compilers implement
524 a stack overflow strategy that cause the handler to be run on a
528 frame_id_inner (struct gdbarch *gdbarch, struct frame_id l, struct frame_id r)
532 if (!l.stack_addr_p || !r.stack_addr_p)
533 /* Like NaN, any operation involving an invalid ID always fails. */
535 else if (l.artificial_depth > r.artificial_depth
536 && l.stack_addr == r.stack_addr
537 && l.code_addr_p == r.code_addr_p
538 && l.special_addr_p == r.special_addr_p
539 && l.special_addr == r.special_addr)
541 /* Same function, different inlined functions. */
542 struct block *lb, *rb;
544 gdb_assert (l.code_addr_p && r.code_addr_p);
546 lb = block_for_pc (l.code_addr);
547 rb = block_for_pc (r.code_addr);
549 if (lb == NULL || rb == NULL)
550 /* Something's gone wrong. */
553 /* This will return true if LB and RB are the same block, or
554 if the block with the smaller depth lexically encloses the
555 block with the greater depth. */
556 inner = contained_in (lb, rb);
559 /* Only return non-zero when strictly inner than. Note that, per
560 comment in "frame.h", there is some fuzz here. Frameless
561 functions are not strictly inner than (same .stack but
562 different .code and/or .special address). */
563 inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr);
566 fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l=");
567 fprint_frame_id (gdb_stdlog, l);
568 fprintf_unfiltered (gdb_stdlog, ",r=");
569 fprint_frame_id (gdb_stdlog, r);
570 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", inner);
576 frame_find_by_id (struct frame_id id)
578 struct frame_info *frame, *prev_frame;
580 /* ZERO denotes the null frame, let the caller decide what to do
581 about it. Should it instead return get_current_frame()? */
582 if (!frame_id_p (id))
585 /* Try using the frame stash first. Finding it there removes the need
586 to perform the search by looping over all frames, which can be very
587 CPU-intensive if the number of frames is very high (the loop is O(n)
588 and get_prev_frame performs a series of checks that are relatively
589 expensive). This optimization is particularly useful when this function
590 is called from another function (such as value_fetch_lazy, case
591 VALUE_LVAL (val) == lval_register) which already loops over all frames,
592 making the overall behavior O(n^2). */
593 frame = frame_stash_find (id);
597 for (frame = get_current_frame (); ; frame = prev_frame)
599 struct frame_id this = get_frame_id (frame);
601 if (frame_id_eq (id, this))
602 /* An exact match. */
605 prev_frame = get_prev_frame (frame);
609 /* As a safety net to avoid unnecessary backtracing while trying
610 to find an invalid ID, we check for a common situation where
611 we can detect from comparing stack addresses that no other
612 frame in the current frame chain can have this ID. See the
613 comment at frame_id_inner for details. */
614 if (get_frame_type (frame) == NORMAL_FRAME
615 && !frame_id_inner (get_frame_arch (frame), id, this)
616 && frame_id_inner (get_frame_arch (prev_frame), id,
617 get_frame_id (prev_frame)))
624 frame_unwind_pc_if_available (struct frame_info *this_frame, CORE_ADDR *pc)
626 if (!this_frame->prev_pc.p)
628 if (gdbarch_unwind_pc_p (frame_unwind_arch (this_frame)))
630 volatile struct gdb_exception ex;
631 struct gdbarch *prev_gdbarch;
634 /* The right way. The `pure' way. The one true way. This
635 method depends solely on the register-unwind code to
636 determine the value of registers in THIS frame, and hence
637 the value of this frame's PC (resume address). A typical
638 implementation is no more than:
640 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf);
641 return extract_unsigned_integer (buf, size of ISA_PC_REGNUM);
643 Note: this method is very heavily dependent on a correct
644 register-unwind implementation, it pays to fix that
645 method first; this method is frame type agnostic, since
646 it only deals with register values, it works with any
647 frame. This is all in stark contrast to the old
648 FRAME_SAVED_PC which would try to directly handle all the
649 different ways that a PC could be unwound. */
650 prev_gdbarch = frame_unwind_arch (this_frame);
652 TRY_CATCH (ex, RETURN_MASK_ERROR)
654 pc = gdbarch_unwind_pc (prev_gdbarch, this_frame);
656 if (ex.reason < 0 && ex.error == NOT_AVAILABLE_ERROR)
658 this_frame->prev_pc.p = -1;
661 fprintf_unfiltered (gdb_stdlog,
662 "{ frame_unwind_pc (this_frame=%d)"
663 " -> <unavailable> }\n",
666 else if (ex.reason < 0)
668 throw_exception (ex);
672 this_frame->prev_pc.value = pc;
673 this_frame->prev_pc.p = 1;
675 fprintf_unfiltered (gdb_stdlog,
676 "{ frame_unwind_pc (this_frame=%d) "
679 hex_string (this_frame->prev_pc.value));
683 internal_error (__FILE__, __LINE__, _("No unwind_pc method"));
685 if (this_frame->prev_pc.p < 0)
692 *pc = this_frame->prev_pc.value;
698 frame_unwind_pc (struct frame_info *this_frame)
702 if (!frame_unwind_pc_if_available (this_frame, &pc))
703 throw_error (NOT_AVAILABLE_ERROR, _("PC not available"));
709 frame_unwind_caller_pc (struct frame_info *this_frame)
711 return frame_unwind_pc (skip_artificial_frames (this_frame));
715 frame_unwind_caller_pc_if_available (struct frame_info *this_frame,
718 return frame_unwind_pc_if_available (skip_artificial_frames (this_frame), pc);
722 get_frame_func_if_available (struct frame_info *this_frame, CORE_ADDR *pc)
724 struct frame_info *next_frame = this_frame->next;
726 if (!next_frame->prev_func.p)
728 CORE_ADDR addr_in_block;
730 /* Make certain that this, and not the adjacent, function is
732 if (!get_frame_address_in_block_if_available (this_frame, &addr_in_block))
734 next_frame->prev_func.p = -1;
736 fprintf_unfiltered (gdb_stdlog,
737 "{ get_frame_func (this_frame=%d)"
738 " -> unavailable }\n",
743 next_frame->prev_func.p = 1;
744 next_frame->prev_func.addr = get_pc_function_start (addr_in_block);
746 fprintf_unfiltered (gdb_stdlog,
747 "{ get_frame_func (this_frame=%d) -> %s }\n",
749 hex_string (next_frame->prev_func.addr));
753 if (next_frame->prev_func.p < 0)
760 *pc = next_frame->prev_func.addr;
766 get_frame_func (struct frame_info *this_frame)
770 if (!get_frame_func_if_available (this_frame, &pc))
771 throw_error (NOT_AVAILABLE_ERROR, _("PC not available"));
776 static enum register_status
777 do_frame_register_read (void *src, int regnum, gdb_byte *buf)
779 if (!frame_register_read (src, regnum, buf))
780 return REG_UNAVAILABLE;
786 frame_save_as_regcache (struct frame_info *this_frame)
788 struct address_space *aspace = get_frame_address_space (this_frame);
789 struct regcache *regcache = regcache_xmalloc (get_frame_arch (this_frame),
791 struct cleanup *cleanups = make_cleanup_regcache_xfree (regcache);
793 regcache_save (regcache, do_frame_register_read, this_frame);
794 discard_cleanups (cleanups);
799 frame_pop (struct frame_info *this_frame)
801 struct frame_info *prev_frame;
802 struct regcache *scratch;
803 struct cleanup *cleanups;
805 if (get_frame_type (this_frame) == DUMMY_FRAME)
807 /* Popping a dummy frame involves restoring more than just registers.
808 dummy_frame_pop does all the work. */
809 dummy_frame_pop (get_frame_id (this_frame));
813 /* Ensure that we have a frame to pop to. */
814 prev_frame = get_prev_frame_1 (this_frame);
817 error (_("Cannot pop the initial frame."));
819 /* Ignore TAILCALL_FRAME type frames, they were executed already before
820 entering THISFRAME. */
821 while (get_frame_type (prev_frame) == TAILCALL_FRAME)
822 prev_frame = get_prev_frame (prev_frame);
824 /* Make a copy of all the register values unwound from this frame.
825 Save them in a scratch buffer so that there isn't a race between
826 trying to extract the old values from the current regcache while
827 at the same time writing new values into that same cache. */
828 scratch = frame_save_as_regcache (prev_frame);
829 cleanups = make_cleanup_regcache_xfree (scratch);
831 /* FIXME: cagney/2003-03-16: It should be possible to tell the
832 target's register cache that it is about to be hit with a burst
833 register transfer and that the sequence of register writes should
834 be batched. The pair target_prepare_to_store() and
835 target_store_registers() kind of suggest this functionality.
836 Unfortunately, they don't implement it. Their lack of a formal
837 definition can lead to targets writing back bogus values
838 (arguably a bug in the target code mind). */
839 /* Now copy those saved registers into the current regcache.
840 Here, regcache_cpy() calls regcache_restore(). */
841 regcache_cpy (get_current_regcache (), scratch);
842 do_cleanups (cleanups);
844 /* We've made right mess of GDB's local state, just discard
846 reinit_frame_cache ();
850 frame_register_unwind (struct frame_info *frame, int regnum,
851 int *optimizedp, int *unavailablep,
852 enum lval_type *lvalp, CORE_ADDR *addrp,
853 int *realnump, gdb_byte *bufferp)
857 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
858 that the value proper does not need to be fetched. */
859 gdb_assert (optimizedp != NULL);
860 gdb_assert (lvalp != NULL);
861 gdb_assert (addrp != NULL);
862 gdb_assert (realnump != NULL);
863 /* gdb_assert (bufferp != NULL); */
865 value = frame_unwind_register_value (frame, regnum);
867 gdb_assert (value != NULL);
869 *optimizedp = value_optimized_out (value);
870 *unavailablep = !value_entirely_available (value);
871 *lvalp = VALUE_LVAL (value);
872 *addrp = value_address (value);
873 *realnump = VALUE_REGNUM (value);
877 if (!*optimizedp && !*unavailablep)
878 memcpy (bufferp, value_contents_all (value),
879 TYPE_LENGTH (value_type (value)));
881 memset (bufferp, 0, TYPE_LENGTH (value_type (value)));
884 /* Dispose of the new value. This prevents watchpoints from
885 trying to watch the saved frame pointer. */
886 release_value (value);
891 frame_register (struct frame_info *frame, int regnum,
892 int *optimizedp, int *unavailablep, enum lval_type *lvalp,
893 CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp)
895 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
896 that the value proper does not need to be fetched. */
897 gdb_assert (optimizedp != NULL);
898 gdb_assert (lvalp != NULL);
899 gdb_assert (addrp != NULL);
900 gdb_assert (realnump != NULL);
901 /* gdb_assert (bufferp != NULL); */
903 /* Obtain the register value by unwinding the register from the next
904 (more inner frame). */
905 gdb_assert (frame != NULL && frame->next != NULL);
906 frame_register_unwind (frame->next, regnum, optimizedp, unavailablep,
907 lvalp, addrp, realnump, bufferp);
911 frame_unwind_register (struct frame_info *frame, int regnum, gdb_byte *buf)
919 frame_register_unwind (frame, regnum, &optimized, &unavailable,
920 &lval, &addr, &realnum, buf);
923 error (_("Register %d was optimized out"), regnum);
925 throw_error (NOT_AVAILABLE_ERROR,
926 _("Register %d is not available"), regnum);
930 get_frame_register (struct frame_info *frame,
931 int regnum, gdb_byte *buf)
933 frame_unwind_register (frame->next, regnum, buf);
937 frame_unwind_register_value (struct frame_info *frame, int regnum)
939 struct gdbarch *gdbarch;
942 gdb_assert (frame != NULL);
943 gdbarch = frame_unwind_arch (frame);
947 fprintf_unfiltered (gdb_stdlog,
948 "{ frame_unwind_register_value "
949 "(frame=%d,regnum=%d(%s),...) ",
950 frame->level, regnum,
951 user_reg_map_regnum_to_name (gdbarch, regnum));
954 /* Find the unwinder. */
955 if (frame->unwind == NULL)
956 frame_unwind_find_by_frame (frame, &frame->prologue_cache);
958 /* Ask this frame to unwind its register. */
959 value = frame->unwind->prev_register (frame, &frame->prologue_cache, regnum);
963 fprintf_unfiltered (gdb_stdlog, "->");
964 if (value_optimized_out (value))
965 fprintf_unfiltered (gdb_stdlog, " optimized out");
968 if (VALUE_LVAL (value) == lval_register)
969 fprintf_unfiltered (gdb_stdlog, " register=%d",
970 VALUE_REGNUM (value));
971 else if (VALUE_LVAL (value) == lval_memory)
972 fprintf_unfiltered (gdb_stdlog, " address=%s",
974 value_address (value)));
976 fprintf_unfiltered (gdb_stdlog, " computed");
978 if (value_lazy (value))
979 fprintf_unfiltered (gdb_stdlog, " lazy");
983 const gdb_byte *buf = value_contents (value);
985 fprintf_unfiltered (gdb_stdlog, " bytes=");
986 fprintf_unfiltered (gdb_stdlog, "[");
987 for (i = 0; i < register_size (gdbarch, regnum); i++)
988 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
989 fprintf_unfiltered (gdb_stdlog, "]");
993 fprintf_unfiltered (gdb_stdlog, " }\n");
1000 get_frame_register_value (struct frame_info *frame, int regnum)
1002 return frame_unwind_register_value (frame->next, regnum);
1006 frame_unwind_register_signed (struct frame_info *frame, int regnum)
1008 struct gdbarch *gdbarch = frame_unwind_arch (frame);
1009 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1010 int size = register_size (gdbarch, regnum);
1011 gdb_byte buf[MAX_REGISTER_SIZE];
1013 frame_unwind_register (frame, regnum, buf);
1014 return extract_signed_integer (buf, size, byte_order);
1018 get_frame_register_signed (struct frame_info *frame, int regnum)
1020 return frame_unwind_register_signed (frame->next, regnum);
1024 frame_unwind_register_unsigned (struct frame_info *frame, int regnum)
1026 struct gdbarch *gdbarch = frame_unwind_arch (frame);
1027 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1028 int size = register_size (gdbarch, regnum);
1029 gdb_byte buf[MAX_REGISTER_SIZE];
1031 frame_unwind_register (frame, regnum, buf);
1032 return extract_unsigned_integer (buf, size, byte_order);
1036 get_frame_register_unsigned (struct frame_info *frame, int regnum)
1038 return frame_unwind_register_unsigned (frame->next, regnum);
1042 read_frame_register_unsigned (struct frame_info *frame, int regnum,
1045 struct value *regval = get_frame_register_value (frame, regnum);
1047 if (!value_optimized_out (regval)
1048 && value_entirely_available (regval))
1050 struct gdbarch *gdbarch = get_frame_arch (frame);
1051 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
1052 int size = register_size (gdbarch, VALUE_REGNUM (regval));
1054 *val = extract_unsigned_integer (value_contents (regval), size, byte_order);
1062 put_frame_register (struct frame_info *frame, int regnum,
1063 const gdb_byte *buf)
1065 struct gdbarch *gdbarch = get_frame_arch (frame);
1069 enum lval_type lval;
1072 frame_register (frame, regnum, &optim, &unavail,
1073 &lval, &addr, &realnum, NULL);
1075 error (_("Attempt to assign to a value that was optimized out."));
1080 write_memory (addr, buf, register_size (gdbarch, regnum));
1084 regcache_cooked_write (get_current_regcache (), realnum, buf);
1087 error (_("Attempt to assign to an unmodifiable value."));
1091 /* This function is deprecated. Use get_frame_register_value instead,
1092 which provides more accurate information.
1094 Find and return the value of REGNUM for the specified stack frame.
1095 The number of bytes copied is REGISTER_SIZE (REGNUM).
1097 Returns 0 if the register value could not be found. */
1100 frame_register_read (struct frame_info *frame, int regnum,
1105 enum lval_type lval;
1109 frame_register (frame, regnum, &optimized, &unavailable,
1110 &lval, &addr, &realnum, myaddr);
1112 return !optimized && !unavailable;
1116 get_frame_register_bytes (struct frame_info *frame, int regnum,
1117 CORE_ADDR offset, int len, gdb_byte *myaddr,
1118 int *optimizedp, int *unavailablep)
1120 struct gdbarch *gdbarch = get_frame_arch (frame);
1125 /* Skip registers wholly inside of OFFSET. */
1126 while (offset >= register_size (gdbarch, regnum))
1128 offset -= register_size (gdbarch, regnum);
1132 /* Ensure that we will not read beyond the end of the register file.
1133 This can only ever happen if the debug information is bad. */
1135 numregs = gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
1136 for (i = regnum; i < numregs; i++)
1138 int thissize = register_size (gdbarch, i);
1141 break; /* This register is not available on this architecture. */
1142 maxsize += thissize;
1145 error (_("Bad debug information detected: "
1146 "Attempt to read %d bytes from registers."), len);
1148 /* Copy the data. */
1151 int curr_len = register_size (gdbarch, regnum) - offset;
1156 if (curr_len == register_size (gdbarch, regnum))
1158 enum lval_type lval;
1162 frame_register (frame, regnum, optimizedp, unavailablep,
1163 &lval, &addr, &realnum, myaddr);
1164 if (*optimizedp || *unavailablep)
1169 gdb_byte buf[MAX_REGISTER_SIZE];
1170 enum lval_type lval;
1174 frame_register (frame, regnum, optimizedp, unavailablep,
1175 &lval, &addr, &realnum, buf);
1176 if (*optimizedp || *unavailablep)
1178 memcpy (myaddr, buf + offset, curr_len);
1193 put_frame_register_bytes (struct frame_info *frame, int regnum,
1194 CORE_ADDR offset, int len, const gdb_byte *myaddr)
1196 struct gdbarch *gdbarch = get_frame_arch (frame);
1198 /* Skip registers wholly inside of OFFSET. */
1199 while (offset >= register_size (gdbarch, regnum))
1201 offset -= register_size (gdbarch, regnum);
1205 /* Copy the data. */
1208 int curr_len = register_size (gdbarch, regnum) - offset;
1213 if (curr_len == register_size (gdbarch, regnum))
1215 put_frame_register (frame, regnum, myaddr);
1219 gdb_byte buf[MAX_REGISTER_SIZE];
1221 frame_register_read (frame, regnum, buf);
1222 memcpy (buf + offset, myaddr, curr_len);
1223 put_frame_register (frame, regnum, buf);
1233 /* Create a sentinel frame. */
1235 static struct frame_info *
1236 create_sentinel_frame (struct program_space *pspace, struct regcache *regcache)
1238 struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
1241 frame->pspace = pspace;
1242 frame->aspace = get_regcache_aspace (regcache);
1243 /* Explicitly initialize the sentinel frame's cache. Provide it
1244 with the underlying regcache. In the future additional
1245 information, such as the frame's thread will be added. */
1246 frame->prologue_cache = sentinel_frame_cache (regcache);
1247 /* For the moment there is only one sentinel frame implementation. */
1248 frame->unwind = &sentinel_frame_unwind;
1249 /* Link this frame back to itself. The frame is self referential
1250 (the unwound PC is the same as the pc), so make it so. */
1251 frame->next = frame;
1252 /* Make the sentinel frame's ID valid, but invalid. That way all
1253 comparisons with it should fail. */
1254 frame->this_id.p = 1;
1255 frame->this_id.value = null_frame_id;
1258 fprintf_unfiltered (gdb_stdlog, "{ create_sentinel_frame (...) -> ");
1259 fprint_frame (gdb_stdlog, frame);
1260 fprintf_unfiltered (gdb_stdlog, " }\n");
1265 /* Info about the innermost stack frame (contents of FP register). */
1267 static struct frame_info *current_frame;
1269 /* Cache for frame addresses already read by gdb. Valid only while
1270 inferior is stopped. Control variables for the frame cache should
1271 be local to this module. */
1273 static struct obstack frame_cache_obstack;
1276 frame_obstack_zalloc (unsigned long size)
1278 void *data = obstack_alloc (&frame_cache_obstack, size);
1280 memset (data, 0, size);
1284 /* Return the innermost (currently executing) stack frame. This is
1285 split into two functions. The function unwind_to_current_frame()
1286 is wrapped in catch exceptions so that, even when the unwind of the
1287 sentinel frame fails, the function still returns a stack frame. */
1290 unwind_to_current_frame (struct ui_out *ui_out, void *args)
1292 struct frame_info *frame = get_prev_frame (args);
1294 /* A sentinel frame can fail to unwind, e.g., because its PC value
1295 lands in somewhere like start. */
1298 current_frame = frame;
1303 get_current_frame (void)
1305 /* First check, and report, the lack of registers. Having GDB
1306 report "No stack!" or "No memory" when the target doesn't even
1307 have registers is very confusing. Besides, "printcmd.exp"
1308 explicitly checks that ``print $pc'' with no registers prints "No
1310 if (!target_has_registers)
1311 error (_("No registers."));
1312 if (!target_has_stack)
1313 error (_("No stack."));
1314 if (!target_has_memory)
1315 error (_("No memory."));
1316 /* Traceframes are effectively a substitute for the live inferior. */
1317 if (get_traceframe_number () < 0)
1319 if (ptid_equal (inferior_ptid, null_ptid))
1320 error (_("No selected thread."));
1321 if (is_exited (inferior_ptid))
1322 error (_("Invalid selected thread."));
1323 if (is_executing (inferior_ptid))
1324 error (_("Target is executing."));
1327 if (current_frame == NULL)
1329 struct frame_info *sentinel_frame =
1330 create_sentinel_frame (current_program_space, get_current_regcache ());
1331 if (catch_exceptions (current_uiout, unwind_to_current_frame,
1332 sentinel_frame, RETURN_MASK_ERROR) != 0)
1334 /* Oops! Fake a current frame? Is this useful? It has a PC
1335 of zero, for instance. */
1336 current_frame = sentinel_frame;
1339 return current_frame;
1342 /* The "selected" stack frame is used by default for local and arg
1343 access. May be zero, for no selected frame. */
1345 static struct frame_info *selected_frame;
1348 has_stack_frames (void)
1350 if (!target_has_registers || !target_has_stack || !target_has_memory)
1353 /* Traceframes are effectively a substitute for the live inferior. */
1354 if (get_traceframe_number () < 0)
1356 /* No current inferior, no frame. */
1357 if (ptid_equal (inferior_ptid, null_ptid))
1360 /* Don't try to read from a dead thread. */
1361 if (is_exited (inferior_ptid))
1364 /* ... or from a spinning thread. */
1365 if (is_executing (inferior_ptid))
1372 /* Return the selected frame. Always non-NULL (unless there isn't an
1373 inferior sufficient for creating a frame) in which case an error is
1377 get_selected_frame (const char *message)
1379 if (selected_frame == NULL)
1381 if (message != NULL && !has_stack_frames ())
1382 error (("%s"), message);
1383 /* Hey! Don't trust this. It should really be re-finding the
1384 last selected frame of the currently selected thread. This,
1385 though, is better than nothing. */
1386 select_frame (get_current_frame ());
1388 /* There is always a frame. */
1389 gdb_assert (selected_frame != NULL);
1390 return selected_frame;
1393 /* If there is a selected frame, return it. Otherwise, return NULL. */
1396 get_selected_frame_if_set (void)
1398 return selected_frame;
1401 /* This is a variant of get_selected_frame() which can be called when
1402 the inferior does not have a frame; in that case it will return
1403 NULL instead of calling error(). */
1406 deprecated_safe_get_selected_frame (void)
1408 if (!has_stack_frames ())
1410 return get_selected_frame (NULL);
1413 /* Select frame FI (or NULL - to invalidate the current frame). */
1416 select_frame (struct frame_info *fi)
1418 selected_frame = fi;
1419 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
1420 frame is being invalidated. */
1421 if (deprecated_selected_frame_level_changed_hook)
1422 deprecated_selected_frame_level_changed_hook (frame_relative_level (fi));
1424 /* FIXME: kseitz/2002-08-28: It would be nice to call
1425 selected_frame_level_changed_event() right here, but due to limitations
1426 in the current interfaces, we would end up flooding UIs with events
1427 because select_frame() is used extensively internally.
1429 Once we have frame-parameterized frame (and frame-related) commands,
1430 the event notification can be moved here, since this function will only
1431 be called when the user's selected frame is being changed. */
1433 /* Ensure that symbols for this frame are read in. Also, determine the
1434 source language of this frame, and switch to it if desired. */
1439 /* We retrieve the frame's symtab by using the frame PC.
1440 However we cannot use the frame PC as-is, because it usually
1441 points to the instruction following the "call", which is
1442 sometimes the first instruction of another function. So we
1443 rely on get_frame_address_in_block() which provides us with a
1444 PC which is guaranteed to be inside the frame's code
1446 if (get_frame_address_in_block_if_available (fi, &pc))
1448 struct symtab *s = find_pc_symtab (pc);
1451 && s->language != current_language->la_language
1452 && s->language != language_unknown
1453 && language_mode == language_mode_auto)
1454 set_language (s->language);
1459 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
1460 Always returns a non-NULL value. */
1463 create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
1465 struct frame_info *fi;
1469 fprintf_unfiltered (gdb_stdlog,
1470 "{ create_new_frame (addr=%s, pc=%s) ",
1471 hex_string (addr), hex_string (pc));
1474 fi = FRAME_OBSTACK_ZALLOC (struct frame_info);
1476 fi->next = create_sentinel_frame (current_program_space,
1477 get_current_regcache ());
1479 /* Set/update this frame's cached PC value, found in the next frame.
1480 Do this before looking for this frame's unwinder. A sniffer is
1481 very likely to read this, and the corresponding unwinder is
1482 entitled to rely that the PC doesn't magically change. */
1483 fi->next->prev_pc.value = pc;
1484 fi->next->prev_pc.p = 1;
1486 /* We currently assume that frame chain's can't cross spaces. */
1487 fi->pspace = fi->next->pspace;
1488 fi->aspace = fi->next->aspace;
1490 /* Select/initialize both the unwind function and the frame's type
1492 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
1495 fi->this_id.value = frame_id_build (addr, pc);
1499 fprintf_unfiltered (gdb_stdlog, "-> ");
1500 fprint_frame (gdb_stdlog, fi);
1501 fprintf_unfiltered (gdb_stdlog, " }\n");
1507 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
1508 innermost frame). Be careful to not fall off the bottom of the
1509 frame chain and onto the sentinel frame. */
1512 get_next_frame (struct frame_info *this_frame)
1514 if (this_frame->level > 0)
1515 return this_frame->next;
1520 /* Observer for the target_changed event. */
1523 frame_observer_target_changed (struct target_ops *target)
1525 reinit_frame_cache ();
1528 /* Flush the entire frame cache. */
1531 reinit_frame_cache (void)
1533 struct frame_info *fi;
1535 /* Tear down all frame caches. */
1536 for (fi = current_frame; fi != NULL; fi = fi->prev)
1538 if (fi->prologue_cache && fi->unwind->dealloc_cache)
1539 fi->unwind->dealloc_cache (fi, fi->prologue_cache);
1540 if (fi->base_cache && fi->base->unwind->dealloc_cache)
1541 fi->base->unwind->dealloc_cache (fi, fi->base_cache);
1544 /* Since we can't really be sure what the first object allocated was. */
1545 obstack_free (&frame_cache_obstack, 0);
1546 obstack_init (&frame_cache_obstack);
1548 if (current_frame != NULL)
1549 annotate_frames_invalid ();
1551 current_frame = NULL; /* Invalidate cache */
1552 select_frame (NULL);
1553 frame_stash_invalidate ();
1555 fprintf_unfiltered (gdb_stdlog, "{ reinit_frame_cache () }\n");
1558 /* Find where a register is saved (in memory or another register).
1559 The result of frame_register_unwind is just where it is saved
1560 relative to this particular frame. */
1563 frame_register_unwind_location (struct frame_info *this_frame, int regnum,
1564 int *optimizedp, enum lval_type *lvalp,
1565 CORE_ADDR *addrp, int *realnump)
1567 gdb_assert (this_frame == NULL || this_frame->level >= 0);
1569 while (this_frame != NULL)
1573 frame_register_unwind (this_frame, regnum, optimizedp, &unavailable,
1574 lvalp, addrp, realnump, NULL);
1579 if (*lvalp != lval_register)
1583 this_frame = get_next_frame (this_frame);
1587 /* Return a "struct frame_info" corresponding to the frame that called
1588 THIS_FRAME. Returns NULL if there is no such frame.
1590 Unlike get_prev_frame, this function always tries to unwind the
1593 static struct frame_info *
1594 get_prev_frame_1 (struct frame_info *this_frame)
1596 struct frame_id this_id;
1597 struct gdbarch *gdbarch;
1599 gdb_assert (this_frame != NULL);
1600 gdbarch = get_frame_arch (this_frame);
1604 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame_1 (this_frame=");
1605 if (this_frame != NULL)
1606 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
1608 fprintf_unfiltered (gdb_stdlog, "<NULL>");
1609 fprintf_unfiltered (gdb_stdlog, ") ");
1612 /* Only try to do the unwind once. */
1613 if (this_frame->prev_p)
1617 fprintf_unfiltered (gdb_stdlog, "-> ");
1618 fprint_frame (gdb_stdlog, this_frame->prev);
1619 fprintf_unfiltered (gdb_stdlog, " // cached \n");
1621 return this_frame->prev;
1624 /* If the frame unwinder hasn't been selected yet, we must do so
1625 before setting prev_p; otherwise the check for misbehaved
1626 sniffers will think that this frame's sniffer tried to unwind
1627 further (see frame_cleanup_after_sniffer). */
1628 if (this_frame->unwind == NULL)
1629 frame_unwind_find_by_frame (this_frame, &this_frame->prologue_cache);
1631 this_frame->prev_p = 1;
1632 this_frame->stop_reason = UNWIND_NO_REASON;
1634 /* If we are unwinding from an inline frame, all of the below tests
1635 were already performed when we unwound from the next non-inline
1636 frame. We must skip them, since we can not get THIS_FRAME's ID
1637 until we have unwound all the way down to the previous non-inline
1639 if (get_frame_type (this_frame) == INLINE_FRAME)
1640 return get_prev_frame_raw (this_frame);
1642 /* Check that this frame is unwindable. If it isn't, don't try to
1643 unwind to the prev frame. */
1644 this_frame->stop_reason
1645 = this_frame->unwind->stop_reason (this_frame,
1646 &this_frame->prologue_cache);
1648 if (this_frame->stop_reason != UNWIND_NO_REASON)
1651 /* Check that this frame's ID was valid. If it wasn't, don't try to
1652 unwind to the prev frame. Be careful to not apply this test to
1653 the sentinel frame. */
1654 this_id = get_frame_id (this_frame);
1655 if (this_frame->level >= 0 && frame_id_eq (this_id, outer_frame_id))
1659 fprintf_unfiltered (gdb_stdlog, "-> ");
1660 fprint_frame (gdb_stdlog, NULL);
1661 fprintf_unfiltered (gdb_stdlog, " // this ID is NULL }\n");
1663 this_frame->stop_reason = UNWIND_NULL_ID;
1667 /* Check that this frame's ID isn't inner to (younger, below, next)
1668 the next frame. This happens when a frame unwind goes backwards.
1669 This check is valid only if this frame and the next frame are NORMAL.
1670 See the comment at frame_id_inner for details. */
1671 if (get_frame_type (this_frame) == NORMAL_FRAME
1672 && this_frame->next->unwind->type == NORMAL_FRAME
1673 && frame_id_inner (get_frame_arch (this_frame->next), this_id,
1674 get_frame_id (this_frame->next)))
1676 CORE_ADDR this_pc_in_block;
1677 struct minimal_symbol *morestack_msym;
1678 const char *morestack_name = NULL;
1680 /* gcc -fsplit-stack __morestack can continue the stack anywhere. */
1681 this_pc_in_block = get_frame_address_in_block (this_frame);
1682 morestack_msym = lookup_minimal_symbol_by_pc (this_pc_in_block);
1684 morestack_name = SYMBOL_LINKAGE_NAME (morestack_msym);
1685 if (!morestack_name || strcmp (morestack_name, "__morestack") != 0)
1689 fprintf_unfiltered (gdb_stdlog, "-> ");
1690 fprint_frame (gdb_stdlog, NULL);
1691 fprintf_unfiltered (gdb_stdlog,
1692 " // this frame ID is inner }\n");
1694 this_frame->stop_reason = UNWIND_INNER_ID;
1699 /* Check that this and the next frame are not identical. If they
1700 are, there is most likely a stack cycle. As with the inner-than
1701 test above, avoid comparing the inner-most and sentinel frames. */
1702 if (this_frame->level > 0
1703 && frame_id_eq (this_id, get_frame_id (this_frame->next)))
1707 fprintf_unfiltered (gdb_stdlog, "-> ");
1708 fprint_frame (gdb_stdlog, NULL);
1709 fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n");
1711 this_frame->stop_reason = UNWIND_SAME_ID;
1715 /* Check that this and the next frame do not unwind the PC register
1716 to the same memory location. If they do, then even though they
1717 have different frame IDs, the new frame will be bogus; two
1718 functions can't share a register save slot for the PC. This can
1719 happen when the prologue analyzer finds a stack adjustment, but
1722 This check does assume that the "PC register" is roughly a
1723 traditional PC, even if the gdbarch_unwind_pc method adjusts
1724 it (we do not rely on the value, only on the unwound PC being
1725 dependent on this value). A potential improvement would be
1726 to have the frame prev_pc method and the gdbarch unwind_pc
1727 method set the same lval and location information as
1728 frame_register_unwind. */
1729 if (this_frame->level > 0
1730 && gdbarch_pc_regnum (gdbarch) >= 0
1731 && get_frame_type (this_frame) == NORMAL_FRAME
1732 && (get_frame_type (this_frame->next) == NORMAL_FRAME
1733 || get_frame_type (this_frame->next) == INLINE_FRAME))
1735 int optimized, realnum, nrealnum;
1736 enum lval_type lval, nlval;
1737 CORE_ADDR addr, naddr;
1739 frame_register_unwind_location (this_frame,
1740 gdbarch_pc_regnum (gdbarch),
1741 &optimized, &lval, &addr, &realnum);
1742 frame_register_unwind_location (get_next_frame (this_frame),
1743 gdbarch_pc_regnum (gdbarch),
1744 &optimized, &nlval, &naddr, &nrealnum);
1746 if ((lval == lval_memory && lval == nlval && addr == naddr)
1747 || (lval == lval_register && lval == nlval && realnum == nrealnum))
1751 fprintf_unfiltered (gdb_stdlog, "-> ");
1752 fprint_frame (gdb_stdlog, NULL);
1753 fprintf_unfiltered (gdb_stdlog, " // no saved PC }\n");
1756 this_frame->stop_reason = UNWIND_NO_SAVED_PC;
1757 this_frame->prev = NULL;
1762 return get_prev_frame_raw (this_frame);
1765 /* Construct a new "struct frame_info" and link it previous to
1768 static struct frame_info *
1769 get_prev_frame_raw (struct frame_info *this_frame)
1771 struct frame_info *prev_frame;
1773 /* Allocate the new frame but do not wire it in to the frame chain.
1774 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
1775 frame->next to pull some fancy tricks (of course such code is, by
1776 definition, recursive). Try to prevent it.
1778 There is no reason to worry about memory leaks, should the
1779 remainder of the function fail. The allocated memory will be
1780 quickly reclaimed when the frame cache is flushed, and the `we've
1781 been here before' check above will stop repeated memory
1782 allocation calls. */
1783 prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
1784 prev_frame->level = this_frame->level + 1;
1786 /* For now, assume we don't have frame chains crossing address
1788 prev_frame->pspace = this_frame->pspace;
1789 prev_frame->aspace = this_frame->aspace;
1791 /* Don't yet compute ->unwind (and hence ->type). It is computed
1792 on-demand in get_frame_type, frame_register_unwind, and
1795 /* Don't yet compute the frame's ID. It is computed on-demand by
1798 /* The unwound frame ID is validate at the start of this function,
1799 as part of the logic to decide if that frame should be further
1800 unwound, and not here while the prev frame is being created.
1801 Doing this makes it possible for the user to examine a frame that
1802 has an invalid frame ID.
1804 Some very old VAX code noted: [...] For the sake of argument,
1805 suppose that the stack is somewhat trashed (which is one reason
1806 that "info frame" exists). So, return 0 (indicating we don't
1807 know the address of the arglist) if we don't know what frame this
1811 this_frame->prev = prev_frame;
1812 prev_frame->next = this_frame;
1816 fprintf_unfiltered (gdb_stdlog, "-> ");
1817 fprint_frame (gdb_stdlog, prev_frame);
1818 fprintf_unfiltered (gdb_stdlog, " }\n");
1824 /* Debug routine to print a NULL frame being returned. */
1827 frame_debug_got_null_frame (struct frame_info *this_frame,
1832 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame (this_frame=");
1833 if (this_frame != NULL)
1834 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
1836 fprintf_unfiltered (gdb_stdlog, "<NULL>");
1837 fprintf_unfiltered (gdb_stdlog, ") -> // %s}\n", reason);
1841 /* Is this (non-sentinel) frame in the "main"() function? */
1844 inside_main_func (struct frame_info *this_frame)
1846 struct minimal_symbol *msymbol;
1849 if (symfile_objfile == 0)
1851 msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
1852 if (msymbol == NULL)
1854 /* Make certain that the code, and not descriptor, address is
1856 maddr = gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame),
1857 SYMBOL_VALUE_ADDRESS (msymbol),
1859 return maddr == get_frame_func (this_frame);
1862 /* Test whether THIS_FRAME is inside the process entry point function. */
1865 inside_entry_func (struct frame_info *this_frame)
1867 CORE_ADDR entry_point;
1869 if (!entry_point_address_query (&entry_point))
1872 return get_frame_func (this_frame) == entry_point;
1875 /* Return a structure containing various interesting information about
1876 the frame that called THIS_FRAME. Returns NULL if there is entier
1877 no such frame or the frame fails any of a set of target-independent
1878 condition that should terminate the frame chain (e.g., as unwinding
1881 This function should not contain target-dependent tests, such as
1882 checking whether the program-counter is zero. */
1885 get_prev_frame (struct frame_info *this_frame)
1890 /* There is always a frame. If this assertion fails, suspect that
1891 something should be calling get_selected_frame() or
1892 get_current_frame(). */
1893 gdb_assert (this_frame != NULL);
1894 frame_pc_p = get_frame_pc_if_available (this_frame, &frame_pc);
1896 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
1897 sense to stop unwinding at a dummy frame. One place where a dummy
1898 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
1899 pcsqh register (space register for the instruction at the head of the
1900 instruction queue) cannot be written directly; the only way to set it
1901 is to branch to code that is in the target space. In order to implement
1902 frame dummies on HPUX, the called function is made to jump back to where
1903 the inferior was when the user function was called. If gdb was inside
1904 the main function when we created the dummy frame, the dummy frame will
1905 point inside the main function. */
1906 if (this_frame->level >= 0
1907 && get_frame_type (this_frame) == NORMAL_FRAME
1908 && !backtrace_past_main
1910 && inside_main_func (this_frame))
1911 /* Don't unwind past main(). Note, this is done _before_ the
1912 frame has been marked as previously unwound. That way if the
1913 user later decides to enable unwinds past main(), that will
1914 automatically happen. */
1916 frame_debug_got_null_frame (this_frame, "inside main func");
1920 /* If the user's backtrace limit has been exceeded, stop. We must
1921 add two to the current level; one of those accounts for backtrace_limit
1922 being 1-based and the level being 0-based, and the other accounts for
1923 the level of the new frame instead of the level of the current
1925 if (this_frame->level + 2 > backtrace_limit)
1927 frame_debug_got_null_frame (this_frame, "backtrace limit exceeded");
1931 /* If we're already inside the entry function for the main objfile,
1932 then it isn't valid. Don't apply this test to a dummy frame -
1933 dummy frame PCs typically land in the entry func. Don't apply
1934 this test to the sentinel frame. Sentinel frames should always
1935 be allowed to unwind. */
1936 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
1937 wasn't checking for "main" in the minimal symbols. With that
1938 fixed asm-source tests now stop in "main" instead of halting the
1939 backtrace in weird and wonderful ways somewhere inside the entry
1940 file. Suspect that tests for inside the entry file/func were
1941 added to work around that (now fixed) case. */
1942 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
1943 suggested having the inside_entry_func test use the
1944 inside_main_func() msymbol trick (along with entry_point_address()
1945 I guess) to determine the address range of the start function.
1946 That should provide a far better stopper than the current
1948 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
1949 applied tail-call optimizations to main so that a function called
1950 from main returns directly to the caller of main. Since we don't
1951 stop at main, we should at least stop at the entry point of the
1953 if (this_frame->level >= 0
1954 && get_frame_type (this_frame) == NORMAL_FRAME
1955 && !backtrace_past_entry
1957 && inside_entry_func (this_frame))
1959 frame_debug_got_null_frame (this_frame, "inside entry func");
1963 /* Assume that the only way to get a zero PC is through something
1964 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
1965 will never unwind a zero PC. */
1966 if (this_frame->level > 0
1967 && (get_frame_type (this_frame) == NORMAL_FRAME
1968 || get_frame_type (this_frame) == INLINE_FRAME)
1969 && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME
1970 && frame_pc_p && frame_pc == 0)
1972 frame_debug_got_null_frame (this_frame, "zero PC");
1976 return get_prev_frame_1 (this_frame);
1980 get_frame_pc (struct frame_info *frame)
1982 gdb_assert (frame->next != NULL);
1983 return frame_unwind_pc (frame->next);
1987 get_frame_pc_if_available (struct frame_info *frame, CORE_ADDR *pc)
1989 volatile struct gdb_exception ex;
1991 gdb_assert (frame->next != NULL);
1993 TRY_CATCH (ex, RETURN_MASK_ERROR)
1995 *pc = frame_unwind_pc (frame->next);
1999 if (ex.error == NOT_AVAILABLE_ERROR)
2002 throw_exception (ex);
2008 /* Return an address that falls within THIS_FRAME's code block. */
2011 get_frame_address_in_block (struct frame_info *this_frame)
2013 /* A draft address. */
2014 CORE_ADDR pc = get_frame_pc (this_frame);
2016 struct frame_info *next_frame = this_frame->next;
2018 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
2019 Normally the resume address is inside the body of the function
2020 associated with THIS_FRAME, but there is a special case: when
2021 calling a function which the compiler knows will never return
2022 (for instance abort), the call may be the very last instruction
2023 in the calling function. The resume address will point after the
2024 call and may be at the beginning of a different function
2027 If THIS_FRAME is a signal frame or dummy frame, then we should
2028 not adjust the unwound PC. For a dummy frame, GDB pushed the
2029 resume address manually onto the stack. For a signal frame, the
2030 OS may have pushed the resume address manually and invoked the
2031 handler (e.g. GNU/Linux), or invoked the trampoline which called
2032 the signal handler - but in either case the signal handler is
2033 expected to return to the trampoline. So in both of these
2034 cases we know that the resume address is executable and
2035 related. So we only need to adjust the PC if THIS_FRAME
2036 is a normal function.
2038 If the program has been interrupted while THIS_FRAME is current,
2039 then clearly the resume address is inside the associated
2040 function. There are three kinds of interruption: debugger stop
2041 (next frame will be SENTINEL_FRAME), operating system
2042 signal or exception (next frame will be SIGTRAMP_FRAME),
2043 or debugger-induced function call (next frame will be
2044 DUMMY_FRAME). So we only need to adjust the PC if
2045 NEXT_FRAME is a normal function.
2047 We check the type of NEXT_FRAME first, since it is already
2048 known; frame type is determined by the unwinder, and since
2049 we have THIS_FRAME we've already selected an unwinder for
2052 If the next frame is inlined, we need to keep going until we find
2053 the real function - for instance, if a signal handler is invoked
2054 while in an inlined function, then the code address of the
2055 "calling" normal function should not be adjusted either. */
2057 while (get_frame_type (next_frame) == INLINE_FRAME)
2058 next_frame = next_frame->next;
2060 if ((get_frame_type (next_frame) == NORMAL_FRAME
2061 || get_frame_type (next_frame) == TAILCALL_FRAME)
2062 && (get_frame_type (this_frame) == NORMAL_FRAME
2063 || get_frame_type (this_frame) == TAILCALL_FRAME
2064 || get_frame_type (this_frame) == INLINE_FRAME))
2071 get_frame_address_in_block_if_available (struct frame_info *this_frame,
2074 volatile struct gdb_exception ex;
2076 TRY_CATCH (ex, RETURN_MASK_ERROR)
2078 *pc = get_frame_address_in_block (this_frame);
2080 if (ex.reason < 0 && ex.error == NOT_AVAILABLE_ERROR)
2082 else if (ex.reason < 0)
2083 throw_exception (ex);
2089 find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal)
2091 struct frame_info *next_frame;
2095 /* If the next frame represents an inlined function call, this frame's
2096 sal is the "call site" of that inlined function, which can not
2097 be inferred from get_frame_pc. */
2098 next_frame = get_next_frame (frame);
2099 if (frame_inlined_callees (frame) > 0)
2104 sym = get_frame_function (next_frame);
2106 sym = inline_skipped_symbol (inferior_ptid);
2108 /* If frame is inline, it certainly has symbols. */
2111 if (SYMBOL_LINE (sym) != 0)
2113 sal->symtab = SYMBOL_SYMTAB (sym);
2114 sal->line = SYMBOL_LINE (sym);
2117 /* If the symbol does not have a location, we don't know where
2118 the call site is. Do not pretend to. This is jarring, but
2119 we can't do much better. */
2120 sal->pc = get_frame_pc (frame);
2122 sal->pspace = get_frame_program_space (frame);
2127 /* If FRAME is not the innermost frame, that normally means that
2128 FRAME->pc points at the return instruction (which is *after* the
2129 call instruction), and we want to get the line containing the
2130 call (because the call is where the user thinks the program is).
2131 However, if the next frame is either a SIGTRAMP_FRAME or a
2132 DUMMY_FRAME, then the next frame will contain a saved interrupt
2133 PC and such a PC indicates the current (rather than next)
2134 instruction/line, consequently, for such cases, want to get the
2135 line containing fi->pc. */
2136 if (!get_frame_pc_if_available (frame, &pc))
2142 notcurrent = (pc != get_frame_address_in_block (frame));
2143 (*sal) = find_pc_line (pc, notcurrent);
2146 /* Per "frame.h", return the ``address'' of the frame. Code should
2147 really be using get_frame_id(). */
2149 get_frame_base (struct frame_info *fi)
2151 return get_frame_id (fi).stack_addr;
2154 /* High-level offsets into the frame. Used by the debug info. */
2157 get_frame_base_address (struct frame_info *fi)
2159 if (get_frame_type (fi) != NORMAL_FRAME)
2161 if (fi->base == NULL)
2162 fi->base = frame_base_find_by_frame (fi);
2163 /* Sneaky: If the low-level unwind and high-level base code share a
2164 common unwinder, let them share the prologue cache. */
2165 if (fi->base->unwind == fi->unwind)
2166 return fi->base->this_base (fi, &fi->prologue_cache);
2167 return fi->base->this_base (fi, &fi->base_cache);
2171 get_frame_locals_address (struct frame_info *fi)
2173 if (get_frame_type (fi) != NORMAL_FRAME)
2175 /* If there isn't a frame address method, find it. */
2176 if (fi->base == NULL)
2177 fi->base = frame_base_find_by_frame (fi);
2178 /* Sneaky: If the low-level unwind and high-level base code share a
2179 common unwinder, let them share the prologue cache. */
2180 if (fi->base->unwind == fi->unwind)
2181 return fi->base->this_locals (fi, &fi->prologue_cache);
2182 return fi->base->this_locals (fi, &fi->base_cache);
2186 get_frame_args_address (struct frame_info *fi)
2188 if (get_frame_type (fi) != NORMAL_FRAME)
2190 /* If there isn't a frame address method, find it. */
2191 if (fi->base == NULL)
2192 fi->base = frame_base_find_by_frame (fi);
2193 /* Sneaky: If the low-level unwind and high-level base code share a
2194 common unwinder, let them share the prologue cache. */
2195 if (fi->base->unwind == fi->unwind)
2196 return fi->base->this_args (fi, &fi->prologue_cache);
2197 return fi->base->this_args (fi, &fi->base_cache);
2200 /* Return true if the frame unwinder for frame FI is UNWINDER; false
2204 frame_unwinder_is (struct frame_info *fi, const struct frame_unwind *unwinder)
2206 if (fi->unwind == NULL)
2207 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
2208 return fi->unwind == unwinder;
2211 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
2212 or -1 for a NULL frame. */
2215 frame_relative_level (struct frame_info *fi)
2224 get_frame_type (struct frame_info *frame)
2226 if (frame->unwind == NULL)
2227 /* Initialize the frame's unwinder because that's what
2228 provides the frame's type. */
2229 frame_unwind_find_by_frame (frame, &frame->prologue_cache);
2230 return frame->unwind->type;
2233 struct program_space *
2234 get_frame_program_space (struct frame_info *frame)
2236 return frame->pspace;
2239 struct program_space *
2240 frame_unwind_program_space (struct frame_info *this_frame)
2242 gdb_assert (this_frame);
2244 /* This is really a placeholder to keep the API consistent --- we
2245 assume for now that we don't have frame chains crossing
2247 return this_frame->pspace;
2250 struct address_space *
2251 get_frame_address_space (struct frame_info *frame)
2253 return frame->aspace;
2256 /* Memory access methods. */
2259 get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr,
2260 gdb_byte *buf, int len)
2262 read_memory (addr, buf, len);
2266 get_frame_memory_signed (struct frame_info *this_frame, CORE_ADDR addr,
2269 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2270 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2272 return read_memory_integer (addr, len, byte_order);
2276 get_frame_memory_unsigned (struct frame_info *this_frame, CORE_ADDR addr,
2279 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2280 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2282 return read_memory_unsigned_integer (addr, len, byte_order);
2286 safe_frame_unwind_memory (struct frame_info *this_frame,
2287 CORE_ADDR addr, gdb_byte *buf, int len)
2289 /* NOTE: target_read_memory returns zero on success! */
2290 return !target_read_memory (addr, buf, len);
2293 /* Architecture methods. */
2296 get_frame_arch (struct frame_info *this_frame)
2298 return frame_unwind_arch (this_frame->next);
2302 frame_unwind_arch (struct frame_info *next_frame)
2304 if (!next_frame->prev_arch.p)
2306 struct gdbarch *arch;
2308 if (next_frame->unwind == NULL)
2309 frame_unwind_find_by_frame (next_frame, &next_frame->prologue_cache);
2311 if (next_frame->unwind->prev_arch != NULL)
2312 arch = next_frame->unwind->prev_arch (next_frame,
2313 &next_frame->prologue_cache);
2315 arch = get_frame_arch (next_frame);
2317 next_frame->prev_arch.arch = arch;
2318 next_frame->prev_arch.p = 1;
2320 fprintf_unfiltered (gdb_stdlog,
2321 "{ frame_unwind_arch (next_frame=%d) -> %s }\n",
2323 gdbarch_bfd_arch_info (arch)->printable_name);
2326 return next_frame->prev_arch.arch;
2330 frame_unwind_caller_arch (struct frame_info *next_frame)
2332 return frame_unwind_arch (skip_artificial_frames (next_frame));
2335 /* Stack pointer methods. */
2338 get_frame_sp (struct frame_info *this_frame)
2340 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2342 /* Normality - an architecture that provides a way of obtaining any
2343 frame inner-most address. */
2344 if (gdbarch_unwind_sp_p (gdbarch))
2345 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
2346 operate on THIS_FRAME now. */
2347 return gdbarch_unwind_sp (gdbarch, this_frame->next);
2348 /* Now things are really are grim. Hope that the value returned by
2349 the gdbarch_sp_regnum register is meaningful. */
2350 if (gdbarch_sp_regnum (gdbarch) >= 0)
2351 return get_frame_register_unsigned (this_frame,
2352 gdbarch_sp_regnum (gdbarch));
2353 internal_error (__FILE__, __LINE__, _("Missing unwind SP method"));
2356 /* Return the reason why we can't unwind past FRAME. */
2358 enum unwind_stop_reason
2359 get_frame_unwind_stop_reason (struct frame_info *frame)
2361 /* If we haven't tried to unwind past this point yet, then assume
2362 that unwinding would succeed. */
2363 if (frame->prev_p == 0)
2364 return UNWIND_NO_REASON;
2366 /* Otherwise, we set a reason when we succeeded (or failed) to
2368 return frame->stop_reason;
2371 /* Return a string explaining REASON. */
2374 frame_stop_reason_string (enum unwind_stop_reason reason)
2378 #define SET(name, description) \
2379 case name: return _(description);
2380 #include "unwind_stop_reasons.def"
2384 internal_error (__FILE__, __LINE__,
2385 "Invalid frame stop reason");
2389 /* Clean up after a failed (wrong unwinder) attempt to unwind past
2393 frame_cleanup_after_sniffer (void *arg)
2395 struct frame_info *frame = arg;
2397 /* The sniffer should not allocate a prologue cache if it did not
2398 match this frame. */
2399 gdb_assert (frame->prologue_cache == NULL);
2401 /* No sniffer should extend the frame chain; sniff based on what is
2403 gdb_assert (!frame->prev_p);
2405 /* The sniffer should not check the frame's ID; that's circular. */
2406 gdb_assert (!frame->this_id.p);
2408 /* Clear cached fields dependent on the unwinder.
2410 The previous PC is independent of the unwinder, but the previous
2411 function is not (see get_frame_address_in_block). */
2412 frame->prev_func.p = 0;
2413 frame->prev_func.addr = 0;
2415 /* Discard the unwinder last, so that we can easily find it if an assertion
2416 in this function triggers. */
2417 frame->unwind = NULL;
2420 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
2421 Return a cleanup which should be called if unwinding fails, and
2422 discarded if it succeeds. */
2425 frame_prepare_for_sniffer (struct frame_info *frame,
2426 const struct frame_unwind *unwind)
2428 gdb_assert (frame->unwind == NULL);
2429 frame->unwind = unwind;
2430 return make_cleanup (frame_cleanup_after_sniffer, frame);
2433 extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */
2435 static struct cmd_list_element *set_backtrace_cmdlist;
2436 static struct cmd_list_element *show_backtrace_cmdlist;
2439 set_backtrace_cmd (char *args, int from_tty)
2441 help_list (set_backtrace_cmdlist, "set backtrace ", -1, gdb_stdout);
2445 show_backtrace_cmd (char *args, int from_tty)
2447 cmd_show_list (show_backtrace_cmdlist, from_tty, "");
2451 _initialize_frame (void)
2453 obstack_init (&frame_cache_obstack);
2455 observer_attach_target_changed (frame_observer_target_changed);
2457 add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, _("\
2458 Set backtrace specific variables.\n\
2459 Configure backtrace variables such as the backtrace limit"),
2460 &set_backtrace_cmdlist, "set backtrace ",
2461 0/*allow-unknown*/, &setlist);
2462 add_prefix_cmd ("backtrace", class_maintenance, show_backtrace_cmd, _("\
2463 Show backtrace specific variables\n\
2464 Show backtrace variables such as the backtrace limit"),
2465 &show_backtrace_cmdlist, "show backtrace ",
2466 0/*allow-unknown*/, &showlist);
2468 add_setshow_boolean_cmd ("past-main", class_obscure,
2469 &backtrace_past_main, _("\
2470 Set whether backtraces should continue past \"main\"."), _("\
2471 Show whether backtraces should continue past \"main\"."), _("\
2472 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
2473 the backtrace at \"main\". Set this variable if you need to see the rest\n\
2474 of the stack trace."),
2476 show_backtrace_past_main,
2477 &set_backtrace_cmdlist,
2478 &show_backtrace_cmdlist);
2480 add_setshow_boolean_cmd ("past-entry", class_obscure,
2481 &backtrace_past_entry, _("\
2482 Set whether backtraces should continue past the entry point of a program."),
2484 Show whether backtraces should continue past the entry point of a program."),
2486 Normally there are no callers beyond the entry point of a program, so GDB\n\
2487 will terminate the backtrace there. Set this variable if you need to see\n\
2488 the rest of the stack trace."),
2490 show_backtrace_past_entry,
2491 &set_backtrace_cmdlist,
2492 &show_backtrace_cmdlist);
2494 add_setshow_uinteger_cmd ("limit", class_obscure,
2495 &backtrace_limit, _("\
2496 Set an upper bound on the number of backtrace levels."), _("\
2497 Show the upper bound on the number of backtrace levels."), _("\
2498 No more than the specified number of frames can be displayed or examined.\n\
2499 Zero is unlimited."),
2501 show_backtrace_limit,
2502 &set_backtrace_cmdlist,
2503 &show_backtrace_cmdlist);
2505 /* Debug this files internals. */
2506 add_setshow_zuinteger_cmd ("frame", class_maintenance, &frame_debug, _("\
2507 Set frame debugging."), _("\
2508 Show frame debugging."), _("\
2509 When non-zero, frame specific internal debugging is enabled."),
2512 &setdebuglist, &showdebuglist);