1 /* Cache and manage frames for GDB, the GNU debugger.
3 Copyright (C) 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, 2001,
4 2002, 2003, 2004, 2007, 2008, 2009, 2010, 2011
5 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
26 #include "inferior.h" /* for inferior_ptid */
28 #include "gdb_assert.h"
29 #include "gdb_string.h"
30 #include "user-regs.h"
31 #include "gdb_obstack.h"
32 #include "dummy-frame.h"
33 #include "sentinel-frame.h"
37 #include "frame-unwind.h"
38 #include "frame-base.h"
43 #include "exceptions.h"
44 #include "gdbthread.h"
46 #include "inline-frame.h"
47 #include "tracepoint.h"
49 static struct frame_info *get_prev_frame_1 (struct frame_info *this_frame);
50 static struct frame_info *get_prev_frame_raw (struct frame_info *this_frame);
52 /* We keep a cache of stack frames, each of which is a "struct
53 frame_info". The innermost one gets allocated (in
54 wait_for_inferior) each time the inferior stops; current_frame
55 points to it. Additional frames get allocated (in get_prev_frame)
56 as needed, and are chained through the next and prev fields. Any
57 time that the frame cache becomes invalid (most notably when we
58 execute something, but also if we change how we interpret the
59 frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything
60 which reads new symbols)), we should call reinit_frame_cache. */
64 /* Level of this frame. The inner-most (youngest) frame is at level
65 0. As you move towards the outer-most (oldest) frame, the level
66 increases. This is a cached value. It could just as easily be
67 computed by counting back from the selected frame to the inner
69 /* NOTE: cagney/2002-04-05: Perhaps a level of ``-1'' should be
70 reserved to indicate a bogus frame - one that has been created
71 just to keep GDB happy (GDB always needs a frame). For the
72 moment leave this as speculation. */
75 /* The frame's program space. */
76 struct program_space *pspace;
78 /* The frame's address space. */
79 struct address_space *aspace;
81 /* The frame's low-level unwinder and corresponding cache. The
82 low-level unwinder is responsible for unwinding register values
83 for the previous frame. The low-level unwind methods are
84 selected based on the presence, or otherwise, of register unwind
85 information such as CFI. */
87 const struct frame_unwind *unwind;
89 /* Cached copy of the previous frame's architecture. */
96 /* Cached copy of the previous frame's resume address. */
102 /* Cached copy of the previous frame's function address. */
109 /* This frame's ID. */
113 struct frame_id value;
116 /* The frame's high-level base methods, and corresponding cache.
117 The high level base methods are selected based on the frame's
119 const struct frame_base *base;
122 /* Pointers to the next (down, inner, younger) and previous (up,
123 outer, older) frame_info's in the frame cache. */
124 struct frame_info *next; /* down, inner, younger */
126 struct frame_info *prev; /* up, outer, older */
128 /* The reason why we could not set PREV, or UNWIND_NO_REASON if we
129 could. Only valid when PREV_P is set. */
130 enum unwind_stop_reason stop_reason;
133 /* A frame stash used to speed up frame lookups. */
135 /* We currently only stash one frame at a time, as this seems to be
136 sufficient for now. */
137 static struct frame_info *frame_stash = NULL;
139 /* Add the following FRAME to the frame stash. */
142 frame_stash_add (struct frame_info *frame)
147 /* Search the frame stash for an entry with the given frame ID.
148 If found, return that frame. Otherwise return NULL. */
150 static struct frame_info *
151 frame_stash_find (struct frame_id id)
153 if (frame_stash && frame_id_eq (frame_stash->this_id.value, id))
159 /* Invalidate the frame stash by removing all entries in it. */
162 frame_stash_invalidate (void)
167 /* Flag to control debugging. */
171 show_frame_debug (struct ui_file *file, int from_tty,
172 struct cmd_list_element *c, const char *value)
174 fprintf_filtered (file, _("Frame debugging is %s.\n"), value);
177 /* Flag to indicate whether backtraces should stop at main et.al. */
179 static int backtrace_past_main;
181 show_backtrace_past_main (struct ui_file *file, int from_tty,
182 struct cmd_list_element *c, const char *value)
184 fprintf_filtered (file,
185 _("Whether backtraces should "
186 "continue past \"main\" is %s.\n"),
190 static int backtrace_past_entry;
192 show_backtrace_past_entry (struct ui_file *file, int from_tty,
193 struct cmd_list_element *c, const char *value)
195 fprintf_filtered (file, _("Whether backtraces should continue past the "
196 "entry point of a program is %s.\n"),
200 static int backtrace_limit = INT_MAX;
202 show_backtrace_limit (struct ui_file *file, int from_tty,
203 struct cmd_list_element *c, const char *value)
205 fprintf_filtered (file,
206 _("An upper bound on the number "
207 "of backtrace levels is %s.\n"),
213 fprint_field (struct ui_file *file, const char *name, int p, CORE_ADDR addr)
216 fprintf_unfiltered (file, "%s=%s", name, hex_string (addr));
218 fprintf_unfiltered (file, "!%s", name);
222 fprint_frame_id (struct ui_file *file, struct frame_id id)
224 fprintf_unfiltered (file, "{");
225 fprint_field (file, "stack", id.stack_addr_p, id.stack_addr);
226 fprintf_unfiltered (file, ",");
227 fprint_field (file, "code", id.code_addr_p, id.code_addr);
228 fprintf_unfiltered (file, ",");
229 fprint_field (file, "special", id.special_addr_p, id.special_addr);
231 fprintf_unfiltered (file, ",inlined=%d", id.inline_depth);
232 fprintf_unfiltered (file, "}");
236 fprint_frame_type (struct ui_file *file, enum frame_type type)
241 fprintf_unfiltered (file, "NORMAL_FRAME");
244 fprintf_unfiltered (file, "DUMMY_FRAME");
247 fprintf_unfiltered (file, "INLINE_FRAME");
250 fprintf_unfiltered (file, "SENTINEL_FRAME");
253 fprintf_unfiltered (file, "SIGTRAMP_FRAME");
256 fprintf_unfiltered (file, "ARCH_FRAME");
259 fprintf_unfiltered (file, "<unknown type>");
265 fprint_frame (struct ui_file *file, struct frame_info *fi)
269 fprintf_unfiltered (file, "<NULL frame>");
272 fprintf_unfiltered (file, "{");
273 fprintf_unfiltered (file, "level=%d", fi->level);
274 fprintf_unfiltered (file, ",");
275 fprintf_unfiltered (file, "type=");
276 if (fi->unwind != NULL)
277 fprint_frame_type (file, fi->unwind->type);
279 fprintf_unfiltered (file, "<unknown>");
280 fprintf_unfiltered (file, ",");
281 fprintf_unfiltered (file, "unwind=");
282 if (fi->unwind != NULL)
283 gdb_print_host_address (fi->unwind, file);
285 fprintf_unfiltered (file, "<unknown>");
286 fprintf_unfiltered (file, ",");
287 fprintf_unfiltered (file, "pc=");
288 if (fi->next != NULL && fi->next->prev_pc.p)
289 fprintf_unfiltered (file, "%s", hex_string (fi->next->prev_pc.value));
291 fprintf_unfiltered (file, "<unknown>");
292 fprintf_unfiltered (file, ",");
293 fprintf_unfiltered (file, "id=");
295 fprint_frame_id (file, fi->this_id.value);
297 fprintf_unfiltered (file, "<unknown>");
298 fprintf_unfiltered (file, ",");
299 fprintf_unfiltered (file, "func=");
300 if (fi->next != NULL && fi->next->prev_func.p)
301 fprintf_unfiltered (file, "%s", hex_string (fi->next->prev_func.addr));
303 fprintf_unfiltered (file, "<unknown>");
304 fprintf_unfiltered (file, "}");
307 /* Given FRAME, return the enclosing normal frame for inlined
308 function frames. Otherwise return the original frame. */
310 static struct frame_info *
311 skip_inlined_frames (struct frame_info *frame)
313 while (get_frame_type (frame) == INLINE_FRAME)
314 frame = get_prev_frame (frame);
319 /* Return a frame uniq ID that can be used to, later, re-find the
323 get_frame_id (struct frame_info *fi)
326 return null_frame_id;
331 fprintf_unfiltered (gdb_stdlog, "{ get_frame_id (fi=%d) ",
333 /* Find the unwinder. */
334 if (fi->unwind == NULL)
335 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
336 /* Find THIS frame's ID. */
337 /* Default to outermost if no ID is found. */
338 fi->this_id.value = outer_frame_id;
339 fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value);
340 gdb_assert (frame_id_p (fi->this_id.value));
344 fprintf_unfiltered (gdb_stdlog, "-> ");
345 fprint_frame_id (gdb_stdlog, fi->this_id.value);
346 fprintf_unfiltered (gdb_stdlog, " }\n");
350 frame_stash_add (fi);
352 return fi->this_id.value;
356 get_stack_frame_id (struct frame_info *next_frame)
358 return get_frame_id (skip_inlined_frames (next_frame));
362 frame_unwind_caller_id (struct frame_info *next_frame)
364 struct frame_info *this_frame;
366 /* Use get_prev_frame_1, and not get_prev_frame. The latter will truncate
367 the frame chain, leading to this function unintentionally
368 returning a null_frame_id (e.g., when a caller requests the frame
369 ID of "main()"s caller. */
371 next_frame = skip_inlined_frames (next_frame);
372 this_frame = get_prev_frame_1 (next_frame);
374 return get_frame_id (skip_inlined_frames (this_frame));
376 return null_frame_id;
379 const struct frame_id null_frame_id; /* All zeros. */
380 const struct frame_id outer_frame_id = { 0, 0, 0, 0, 0, 1, 0 };
383 frame_id_build_special (CORE_ADDR stack_addr, CORE_ADDR code_addr,
384 CORE_ADDR special_addr)
386 struct frame_id id = null_frame_id;
388 id.stack_addr = stack_addr;
390 id.code_addr = code_addr;
392 id.special_addr = special_addr;
393 id.special_addr_p = 1;
398 frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr)
400 struct frame_id id = null_frame_id;
402 id.stack_addr = stack_addr;
404 id.code_addr = code_addr;
410 frame_id_build_wild (CORE_ADDR stack_addr)
412 struct frame_id id = null_frame_id;
414 id.stack_addr = stack_addr;
420 frame_id_p (struct frame_id l)
424 /* The frame is valid iff it has a valid stack address. */
426 /* outer_frame_id is also valid. */
427 if (!p && memcmp (&l, &outer_frame_id, sizeof (l)) == 0)
431 fprintf_unfiltered (gdb_stdlog, "{ frame_id_p (l=");
432 fprint_frame_id (gdb_stdlog, l);
433 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", p);
439 frame_id_inlined_p (struct frame_id l)
444 return (l.inline_depth != 0);
448 frame_id_eq (struct frame_id l, struct frame_id r)
452 if (!l.stack_addr_p && l.special_addr_p
453 && !r.stack_addr_p && r.special_addr_p)
454 /* The outermost frame marker is equal to itself. This is the
455 dodgy thing about outer_frame_id, since between execution steps
456 we might step into another function - from which we can't
457 unwind either. More thought required to get rid of
460 else if (!l.stack_addr_p || !r.stack_addr_p)
461 /* Like a NaN, if either ID is invalid, the result is false.
462 Note that a frame ID is invalid iff it is the null frame ID. */
464 else if (l.stack_addr != r.stack_addr)
465 /* If .stack addresses are different, the frames are different. */
467 else if (l.code_addr_p && r.code_addr_p && l.code_addr != r.code_addr)
468 /* An invalid code addr is a wild card. If .code addresses are
469 different, the frames are different. */
471 else if (l.special_addr_p && r.special_addr_p
472 && l.special_addr != r.special_addr)
473 /* An invalid special addr is a wild card (or unused). Otherwise
474 if special addresses are different, the frames are different. */
476 else if (l.inline_depth != r.inline_depth)
477 /* If inline depths are different, the frames must be different. */
480 /* Frames are equal. */
485 fprintf_unfiltered (gdb_stdlog, "{ frame_id_eq (l=");
486 fprint_frame_id (gdb_stdlog, l);
487 fprintf_unfiltered (gdb_stdlog, ",r=");
488 fprint_frame_id (gdb_stdlog, r);
489 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", eq);
494 /* Safety net to check whether frame ID L should be inner to
495 frame ID R, according to their stack addresses.
497 This method cannot be used to compare arbitrary frames, as the
498 ranges of valid stack addresses may be discontiguous (e.g. due
501 However, it can be used as safety net to discover invalid frame
502 IDs in certain circumstances. Assuming that NEXT is the immediate
503 inner frame to THIS and that NEXT and THIS are both NORMAL frames:
505 * The stack address of NEXT must be inner-than-or-equal to the stack
508 Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind
511 * If NEXT and THIS have different stack addresses, no other frame
512 in the frame chain may have a stack address in between.
514 Therefore, if frame_id_inner (TEST, THIS) holds, but
515 frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer
516 to a valid frame in the frame chain.
518 The sanity checks above cannot be performed when a SIGTRAMP frame
519 is involved, because signal handlers might be executed on a different
520 stack than the stack used by the routine that caused the signal
521 to be raised. This can happen for instance when a thread exceeds
522 its maximum stack size. In this case, certain compilers implement
523 a stack overflow strategy that cause the handler to be run on a
527 frame_id_inner (struct gdbarch *gdbarch, struct frame_id l, struct frame_id r)
531 if (!l.stack_addr_p || !r.stack_addr_p)
532 /* Like NaN, any operation involving an invalid ID always fails. */
534 else if (l.inline_depth > r.inline_depth
535 && l.stack_addr == r.stack_addr
536 && l.code_addr_p == r.code_addr_p
537 && l.special_addr_p == r.special_addr_p
538 && l.special_addr == r.special_addr)
540 /* Same function, different inlined functions. */
541 struct block *lb, *rb;
543 gdb_assert (l.code_addr_p && r.code_addr_p);
545 lb = block_for_pc (l.code_addr);
546 rb = block_for_pc (r.code_addr);
548 if (lb == NULL || rb == NULL)
549 /* Something's gone wrong. */
552 /* This will return true if LB and RB are the same block, or
553 if the block with the smaller depth lexically encloses the
554 block with the greater depth. */
555 inner = contained_in (lb, rb);
558 /* Only return non-zero when strictly inner than. Note that, per
559 comment in "frame.h", there is some fuzz here. Frameless
560 functions are not strictly inner than (same .stack but
561 different .code and/or .special address). */
562 inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr);
565 fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l=");
566 fprint_frame_id (gdb_stdlog, l);
567 fprintf_unfiltered (gdb_stdlog, ",r=");
568 fprint_frame_id (gdb_stdlog, r);
569 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", inner);
575 frame_find_by_id (struct frame_id id)
577 struct frame_info *frame, *prev_frame;
579 /* ZERO denotes the null frame, let the caller decide what to do
580 about it. Should it instead return get_current_frame()? */
581 if (!frame_id_p (id))
584 /* Try using the frame stash first. Finding it there removes the need
585 to perform the search by looping over all frames, which can be very
586 CPU-intensive if the number of frames is very high (the loop is O(n)
587 and get_prev_frame performs a series of checks that are relatively
588 expensive). This optimization is particularly useful when this function
589 is called from another function (such as value_fetch_lazy, case
590 VALUE_LVAL (val) == lval_register) which already loops over all frames,
591 making the overall behavior O(n^2). */
592 frame = frame_stash_find (id);
596 for (frame = get_current_frame (); ; frame = prev_frame)
598 struct frame_id this = get_frame_id (frame);
600 if (frame_id_eq (id, this))
601 /* An exact match. */
604 prev_frame = get_prev_frame (frame);
608 /* As a safety net to avoid unnecessary backtracing while trying
609 to find an invalid ID, we check for a common situation where
610 we can detect from comparing stack addresses that no other
611 frame in the current frame chain can have this ID. See the
612 comment at frame_id_inner for details. */
613 if (get_frame_type (frame) == NORMAL_FRAME
614 && !frame_id_inner (get_frame_arch (frame), id, this)
615 && frame_id_inner (get_frame_arch (prev_frame), id,
616 get_frame_id (prev_frame)))
623 frame_unwind_pc (struct frame_info *this_frame)
625 if (!this_frame->prev_pc.p)
629 if (gdbarch_unwind_pc_p (frame_unwind_arch (this_frame)))
631 /* The right way. The `pure' way. The one true way. This
632 method depends solely on the register-unwind code to
633 determine the value of registers in THIS frame, and hence
634 the value of this frame's PC (resume address). A typical
635 implementation is no more than:
637 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf);
638 return extract_unsigned_integer (buf, size of ISA_PC_REGNUM);
640 Note: this method is very heavily dependent on a correct
641 register-unwind implementation, it pays to fix that
642 method first; this method is frame type agnostic, since
643 it only deals with register values, it works with any
644 frame. This is all in stark contrast to the old
645 FRAME_SAVED_PC which would try to directly handle all the
646 different ways that a PC could be unwound. */
647 pc = gdbarch_unwind_pc (frame_unwind_arch (this_frame), this_frame);
650 internal_error (__FILE__, __LINE__, _("No unwind_pc method"));
651 this_frame->prev_pc.value = pc;
652 this_frame->prev_pc.p = 1;
654 fprintf_unfiltered (gdb_stdlog,
655 "{ frame_unwind_caller_pc "
656 "(this_frame=%d) -> %s }\n",
658 hex_string (this_frame->prev_pc.value));
660 return this_frame->prev_pc.value;
664 frame_unwind_caller_pc (struct frame_info *this_frame)
666 return frame_unwind_pc (skip_inlined_frames (this_frame));
670 get_frame_func (struct frame_info *this_frame)
672 struct frame_info *next_frame = this_frame->next;
674 if (!next_frame->prev_func.p)
676 /* Make certain that this, and not the adjacent, function is
678 CORE_ADDR addr_in_block = get_frame_address_in_block (this_frame);
679 next_frame->prev_func.p = 1;
680 next_frame->prev_func.addr = get_pc_function_start (addr_in_block);
682 fprintf_unfiltered (gdb_stdlog,
683 "{ get_frame_func (this_frame=%d) -> %s }\n",
685 hex_string (next_frame->prev_func.addr));
687 return next_frame->prev_func.addr;
691 do_frame_register_read (void *src, int regnum, gdb_byte *buf)
693 return frame_register_read (src, regnum, buf);
697 frame_save_as_regcache (struct frame_info *this_frame)
699 struct address_space *aspace = get_frame_address_space (this_frame);
700 struct regcache *regcache = regcache_xmalloc (get_frame_arch (this_frame),
702 struct cleanup *cleanups = make_cleanup_regcache_xfree (regcache);
704 regcache_save (regcache, do_frame_register_read, this_frame);
705 discard_cleanups (cleanups);
710 frame_pop (struct frame_info *this_frame)
712 struct frame_info *prev_frame;
713 struct regcache *scratch;
714 struct cleanup *cleanups;
716 if (get_frame_type (this_frame) == DUMMY_FRAME)
718 /* Popping a dummy frame involves restoring more than just registers.
719 dummy_frame_pop does all the work. */
720 dummy_frame_pop (get_frame_id (this_frame));
724 /* Ensure that we have a frame to pop to. */
725 prev_frame = get_prev_frame_1 (this_frame);
728 error (_("Cannot pop the initial frame."));
730 /* Make a copy of all the register values unwound from this frame.
731 Save them in a scratch buffer so that there isn't a race between
732 trying to extract the old values from the current regcache while
733 at the same time writing new values into that same cache. */
734 scratch = frame_save_as_regcache (prev_frame);
735 cleanups = make_cleanup_regcache_xfree (scratch);
737 /* FIXME: cagney/2003-03-16: It should be possible to tell the
738 target's register cache that it is about to be hit with a burst
739 register transfer and that the sequence of register writes should
740 be batched. The pair target_prepare_to_store() and
741 target_store_registers() kind of suggest this functionality.
742 Unfortunately, they don't implement it. Their lack of a formal
743 definition can lead to targets writing back bogus values
744 (arguably a bug in the target code mind). */
745 /* Now copy those saved registers into the current regcache.
746 Here, regcache_cpy() calls regcache_restore(). */
747 regcache_cpy (get_current_regcache (), scratch);
748 do_cleanups (cleanups);
750 /* We've made right mess of GDB's local state, just discard
752 reinit_frame_cache ();
756 frame_register_unwind (struct frame_info *frame, int regnum,
757 int *optimizedp, enum lval_type *lvalp,
758 CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp)
762 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
763 that the value proper does not need to be fetched. */
764 gdb_assert (optimizedp != NULL);
765 gdb_assert (lvalp != NULL);
766 gdb_assert (addrp != NULL);
767 gdb_assert (realnump != NULL);
768 /* gdb_assert (bufferp != NULL); */
770 value = frame_unwind_register_value (frame, regnum);
772 gdb_assert (value != NULL);
774 *optimizedp = value_optimized_out (value);
775 *lvalp = VALUE_LVAL (value);
776 *addrp = value_address (value);
777 *realnump = VALUE_REGNUM (value);
779 if (bufferp && !*optimizedp)
780 memcpy (bufferp, value_contents_all (value),
781 TYPE_LENGTH (value_type (value)));
783 /* Dispose of the new value. This prevents watchpoints from
784 trying to watch the saved frame pointer. */
785 release_value (value);
790 frame_register (struct frame_info *frame, int regnum,
791 int *optimizedp, enum lval_type *lvalp,
792 CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp)
794 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
795 that the value proper does not need to be fetched. */
796 gdb_assert (optimizedp != NULL);
797 gdb_assert (lvalp != NULL);
798 gdb_assert (addrp != NULL);
799 gdb_assert (realnump != NULL);
800 /* gdb_assert (bufferp != NULL); */
802 /* Obtain the register value by unwinding the register from the next
803 (more inner frame). */
804 gdb_assert (frame != NULL && frame->next != NULL);
805 frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
810 frame_unwind_register (struct frame_info *frame, int regnum, gdb_byte *buf)
817 frame_register_unwind (frame, regnum, &optimized, &lval, &addr,
822 get_frame_register (struct frame_info *frame,
823 int regnum, gdb_byte *buf)
825 frame_unwind_register (frame->next, regnum, buf);
829 frame_unwind_register_value (struct frame_info *frame, int regnum)
831 struct gdbarch *gdbarch;
834 gdb_assert (frame != NULL);
835 gdbarch = frame_unwind_arch (frame);
839 fprintf_unfiltered (gdb_stdlog,
840 "{ frame_unwind_register_value "
841 "(frame=%d,regnum=%d(%s),...) ",
842 frame->level, regnum,
843 user_reg_map_regnum_to_name (gdbarch, regnum));
846 /* Find the unwinder. */
847 if (frame->unwind == NULL)
848 frame_unwind_find_by_frame (frame, &frame->prologue_cache);
850 /* Ask this frame to unwind its register. */
851 value = frame->unwind->prev_register (frame, &frame->prologue_cache, regnum);
855 fprintf_unfiltered (gdb_stdlog, "->");
856 if (value_optimized_out (value))
857 fprintf_unfiltered (gdb_stdlog, " optimized out");
860 if (VALUE_LVAL (value) == lval_register)
861 fprintf_unfiltered (gdb_stdlog, " register=%d",
862 VALUE_REGNUM (value));
863 else if (VALUE_LVAL (value) == lval_memory)
864 fprintf_unfiltered (gdb_stdlog, " address=%s",
866 value_address (value)));
868 fprintf_unfiltered (gdb_stdlog, " computed");
870 if (value_lazy (value))
871 fprintf_unfiltered (gdb_stdlog, " lazy");
875 const gdb_byte *buf = value_contents (value);
877 fprintf_unfiltered (gdb_stdlog, " bytes=");
878 fprintf_unfiltered (gdb_stdlog, "[");
879 for (i = 0; i < register_size (gdbarch, regnum); i++)
880 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
881 fprintf_unfiltered (gdb_stdlog, "]");
885 fprintf_unfiltered (gdb_stdlog, " }\n");
892 get_frame_register_value (struct frame_info *frame, int regnum)
894 return frame_unwind_register_value (frame->next, regnum);
898 frame_unwind_register_signed (struct frame_info *frame, int regnum)
900 struct gdbarch *gdbarch = frame_unwind_arch (frame);
901 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
902 int size = register_size (gdbarch, regnum);
903 gdb_byte buf[MAX_REGISTER_SIZE];
905 frame_unwind_register (frame, regnum, buf);
906 return extract_signed_integer (buf, size, byte_order);
910 get_frame_register_signed (struct frame_info *frame, int regnum)
912 return frame_unwind_register_signed (frame->next, regnum);
916 frame_unwind_register_unsigned (struct frame_info *frame, int regnum)
918 struct gdbarch *gdbarch = frame_unwind_arch (frame);
919 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
920 int size = register_size (gdbarch, regnum);
921 gdb_byte buf[MAX_REGISTER_SIZE];
923 frame_unwind_register (frame, regnum, buf);
924 return extract_unsigned_integer (buf, size, byte_order);
928 get_frame_register_unsigned (struct frame_info *frame, int regnum)
930 return frame_unwind_register_unsigned (frame->next, regnum);
934 put_frame_register (struct frame_info *frame, int regnum,
937 struct gdbarch *gdbarch = get_frame_arch (frame);
943 frame_register (frame, regnum, &optim, &lval, &addr, &realnum, NULL);
945 error (_("Attempt to assign to a value that was optimized out."));
950 /* FIXME: write_memory doesn't yet take constant buffers.
952 gdb_byte tmp[MAX_REGISTER_SIZE];
954 memcpy (tmp, buf, register_size (gdbarch, regnum));
955 write_memory (addr, tmp, register_size (gdbarch, regnum));
959 regcache_cooked_write (get_current_regcache (), realnum, buf);
962 error (_("Attempt to assign to an unmodifiable value."));
966 /* frame_register_read ()
968 Find and return the value of REGNUM for the specified stack frame.
969 The number of bytes copied is REGISTER_SIZE (REGNUM).
971 Returns 0 if the register value could not be found. */
974 frame_register_read (struct frame_info *frame, int regnum,
982 frame_register (frame, regnum, &optimized, &lval, &addr, &realnum, myaddr);
988 get_frame_register_bytes (struct frame_info *frame, int regnum,
989 CORE_ADDR offset, int len, gdb_byte *myaddr)
991 struct gdbarch *gdbarch = get_frame_arch (frame);
996 /* Skip registers wholly inside of OFFSET. */
997 while (offset >= register_size (gdbarch, regnum))
999 offset -= register_size (gdbarch, regnum);
1003 /* Ensure that we will not read beyond the end of the register file.
1004 This can only ever happen if the debug information is bad. */
1006 numregs = gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
1007 for (i = regnum; i < numregs; i++)
1009 int thissize = register_size (gdbarch, i);
1012 break; /* This register is not available on this architecture. */
1013 maxsize += thissize;
1017 warning (_("Bad debug information detected: "
1018 "Attempt to read %d bytes from registers."), len);
1022 /* Copy the data. */
1025 int curr_len = register_size (gdbarch, regnum) - offset;
1030 if (curr_len == register_size (gdbarch, regnum))
1032 if (!frame_register_read (frame, regnum, myaddr))
1037 gdb_byte buf[MAX_REGISTER_SIZE];
1039 if (!frame_register_read (frame, regnum, buf))
1041 memcpy (myaddr, buf + offset, curr_len);
1054 put_frame_register_bytes (struct frame_info *frame, int regnum,
1055 CORE_ADDR offset, int len, const gdb_byte *myaddr)
1057 struct gdbarch *gdbarch = get_frame_arch (frame);
1059 /* Skip registers wholly inside of OFFSET. */
1060 while (offset >= register_size (gdbarch, regnum))
1062 offset -= register_size (gdbarch, regnum);
1066 /* Copy the data. */
1069 int curr_len = register_size (gdbarch, regnum) - offset;
1074 if (curr_len == register_size (gdbarch, regnum))
1076 put_frame_register (frame, regnum, myaddr);
1080 gdb_byte buf[MAX_REGISTER_SIZE];
1082 frame_register_read (frame, regnum, buf);
1083 memcpy (buf + offset, myaddr, curr_len);
1084 put_frame_register (frame, regnum, buf);
1094 /* Create a sentinel frame. */
1096 static struct frame_info *
1097 create_sentinel_frame (struct program_space *pspace, struct regcache *regcache)
1099 struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
1102 frame->pspace = pspace;
1103 frame->aspace = get_regcache_aspace (regcache);
1104 /* Explicitly initialize the sentinel frame's cache. Provide it
1105 with the underlying regcache. In the future additional
1106 information, such as the frame's thread will be added. */
1107 frame->prologue_cache = sentinel_frame_cache (regcache);
1108 /* For the moment there is only one sentinel frame implementation. */
1109 frame->unwind = &sentinel_frame_unwind;
1110 /* Link this frame back to itself. The frame is self referential
1111 (the unwound PC is the same as the pc), so make it so. */
1112 frame->next = frame;
1113 /* Make the sentinel frame's ID valid, but invalid. That way all
1114 comparisons with it should fail. */
1115 frame->this_id.p = 1;
1116 frame->this_id.value = null_frame_id;
1119 fprintf_unfiltered (gdb_stdlog, "{ create_sentinel_frame (...) -> ");
1120 fprint_frame (gdb_stdlog, frame);
1121 fprintf_unfiltered (gdb_stdlog, " }\n");
1126 /* Info about the innermost stack frame (contents of FP register). */
1128 static struct frame_info *current_frame;
1130 /* Cache for frame addresses already read by gdb. Valid only while
1131 inferior is stopped. Control variables for the frame cache should
1132 be local to this module. */
1134 static struct obstack frame_cache_obstack;
1137 frame_obstack_zalloc (unsigned long size)
1139 void *data = obstack_alloc (&frame_cache_obstack, size);
1141 memset (data, 0, size);
1145 /* Return the innermost (currently executing) stack frame. This is
1146 split into two functions. The function unwind_to_current_frame()
1147 is wrapped in catch exceptions so that, even when the unwind of the
1148 sentinel frame fails, the function still returns a stack frame. */
1151 unwind_to_current_frame (struct ui_out *ui_out, void *args)
1153 struct frame_info *frame = get_prev_frame (args);
1155 /* A sentinel frame can fail to unwind, e.g., because its PC value
1156 lands in somewhere like start. */
1159 current_frame = frame;
1164 get_current_frame (void)
1166 /* First check, and report, the lack of registers. Having GDB
1167 report "No stack!" or "No memory" when the target doesn't even
1168 have registers is very confusing. Besides, "printcmd.exp"
1169 explicitly checks that ``print $pc'' with no registers prints "No
1171 if (!target_has_registers)
1172 error (_("No registers."));
1173 if (!target_has_stack)
1174 error (_("No stack."));
1175 if (!target_has_memory)
1176 error (_("No memory."));
1177 /* Traceframes are effectively a substitute for the live inferior. */
1178 if (get_traceframe_number () < 0)
1180 if (ptid_equal (inferior_ptid, null_ptid))
1181 error (_("No selected thread."));
1182 if (is_exited (inferior_ptid))
1183 error (_("Invalid selected thread."));
1184 if (is_executing (inferior_ptid))
1185 error (_("Target is executing."));
1188 if (current_frame == NULL)
1190 struct frame_info *sentinel_frame =
1191 create_sentinel_frame (current_program_space, get_current_regcache ());
1192 if (catch_exceptions (uiout, unwind_to_current_frame, sentinel_frame,
1193 RETURN_MASK_ERROR) != 0)
1195 /* Oops! Fake a current frame? Is this useful? It has a PC
1196 of zero, for instance. */
1197 current_frame = sentinel_frame;
1200 return current_frame;
1203 /* The "selected" stack frame is used by default for local and arg
1204 access. May be zero, for no selected frame. */
1206 static struct frame_info *selected_frame;
1209 has_stack_frames (void)
1211 if (!target_has_registers || !target_has_stack || !target_has_memory)
1214 /* No current inferior, no frame. */
1215 if (ptid_equal (inferior_ptid, null_ptid))
1218 /* Don't try to read from a dead thread. */
1219 if (is_exited (inferior_ptid))
1222 /* ... or from a spinning thread. */
1223 if (is_executing (inferior_ptid))
1229 /* Return the selected frame. Always non-NULL (unless there isn't an
1230 inferior sufficient for creating a frame) in which case an error is
1234 get_selected_frame (const char *message)
1236 if (selected_frame == NULL)
1238 if (message != NULL && !has_stack_frames ())
1239 error (("%s"), message);
1240 /* Hey! Don't trust this. It should really be re-finding the
1241 last selected frame of the currently selected thread. This,
1242 though, is better than nothing. */
1243 select_frame (get_current_frame ());
1245 /* There is always a frame. */
1246 gdb_assert (selected_frame != NULL);
1247 return selected_frame;
1250 /* If there is a selected frame, return it. Otherwise, return NULL. */
1253 get_selected_frame_if_set (void)
1255 return selected_frame;
1258 /* This is a variant of get_selected_frame() which can be called when
1259 the inferior does not have a frame; in that case it will return
1260 NULL instead of calling error(). */
1263 deprecated_safe_get_selected_frame (void)
1265 if (!has_stack_frames ())
1267 return get_selected_frame (NULL);
1270 /* Select frame FI (or NULL - to invalidate the current frame). */
1273 select_frame (struct frame_info *fi)
1277 selected_frame = fi;
1278 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
1279 frame is being invalidated. */
1280 if (deprecated_selected_frame_level_changed_hook)
1281 deprecated_selected_frame_level_changed_hook (frame_relative_level (fi));
1283 /* FIXME: kseitz/2002-08-28: It would be nice to call
1284 selected_frame_level_changed_event() right here, but due to limitations
1285 in the current interfaces, we would end up flooding UIs with events
1286 because select_frame() is used extensively internally.
1288 Once we have frame-parameterized frame (and frame-related) commands,
1289 the event notification can be moved here, since this function will only
1290 be called when the user's selected frame is being changed. */
1292 /* Ensure that symbols for this frame are read in. Also, determine the
1293 source language of this frame, and switch to it if desired. */
1296 /* We retrieve the frame's symtab by using the frame PC. However
1297 we cannot use the frame PC as-is, because it usually points to
1298 the instruction following the "call", which is sometimes the
1299 first instruction of another function. So we rely on
1300 get_frame_address_in_block() which provides us with a PC which
1301 is guaranteed to be inside the frame's code block. */
1302 s = find_pc_symtab (get_frame_address_in_block (fi));
1304 && s->language != current_language->la_language
1305 && s->language != language_unknown
1306 && language_mode == language_mode_auto)
1308 set_language (s->language);
1313 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
1314 Always returns a non-NULL value. */
1317 create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
1319 struct frame_info *fi;
1323 fprintf_unfiltered (gdb_stdlog,
1324 "{ create_new_frame (addr=%s, pc=%s) ",
1325 hex_string (addr), hex_string (pc));
1328 fi = FRAME_OBSTACK_ZALLOC (struct frame_info);
1330 fi->next = create_sentinel_frame (current_program_space,
1331 get_current_regcache ());
1333 /* Set/update this frame's cached PC value, found in the next frame.
1334 Do this before looking for this frame's unwinder. A sniffer is
1335 very likely to read this, and the corresponding unwinder is
1336 entitled to rely that the PC doesn't magically change. */
1337 fi->next->prev_pc.value = pc;
1338 fi->next->prev_pc.p = 1;
1340 /* We currently assume that frame chain's can't cross spaces. */
1341 fi->pspace = fi->next->pspace;
1342 fi->aspace = fi->next->aspace;
1344 /* Select/initialize both the unwind function and the frame's type
1346 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
1349 fi->this_id.value = frame_id_build (addr, pc);
1353 fprintf_unfiltered (gdb_stdlog, "-> ");
1354 fprint_frame (gdb_stdlog, fi);
1355 fprintf_unfiltered (gdb_stdlog, " }\n");
1361 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
1362 innermost frame). Be careful to not fall off the bottom of the
1363 frame chain and onto the sentinel frame. */
1366 get_next_frame (struct frame_info *this_frame)
1368 if (this_frame->level > 0)
1369 return this_frame->next;
1374 /* Observer for the target_changed event. */
1377 frame_observer_target_changed (struct target_ops *target)
1379 reinit_frame_cache ();
1382 /* Flush the entire frame cache. */
1385 reinit_frame_cache (void)
1387 struct frame_info *fi;
1389 /* Tear down all frame caches. */
1390 for (fi = current_frame; fi != NULL; fi = fi->prev)
1392 if (fi->prologue_cache && fi->unwind->dealloc_cache)
1393 fi->unwind->dealloc_cache (fi, fi->prologue_cache);
1394 if (fi->base_cache && fi->base->unwind->dealloc_cache)
1395 fi->base->unwind->dealloc_cache (fi, fi->base_cache);
1398 /* Since we can't really be sure what the first object allocated was. */
1399 obstack_free (&frame_cache_obstack, 0);
1400 obstack_init (&frame_cache_obstack);
1402 if (current_frame != NULL)
1403 annotate_frames_invalid ();
1405 current_frame = NULL; /* Invalidate cache */
1406 select_frame (NULL);
1407 frame_stash_invalidate ();
1409 fprintf_unfiltered (gdb_stdlog, "{ reinit_frame_cache () }\n");
1412 /* Find where a register is saved (in memory or another register).
1413 The result of frame_register_unwind is just where it is saved
1414 relative to this particular frame. */
1417 frame_register_unwind_location (struct frame_info *this_frame, int regnum,
1418 int *optimizedp, enum lval_type *lvalp,
1419 CORE_ADDR *addrp, int *realnump)
1421 gdb_assert (this_frame == NULL || this_frame->level >= 0);
1423 while (this_frame != NULL)
1425 frame_register_unwind (this_frame, regnum, optimizedp, lvalp,
1426 addrp, realnump, NULL);
1431 if (*lvalp != lval_register)
1435 this_frame = get_next_frame (this_frame);
1439 /* Return a "struct frame_info" corresponding to the frame that called
1440 THIS_FRAME. Returns NULL if there is no such frame.
1442 Unlike get_prev_frame, this function always tries to unwind the
1445 static struct frame_info *
1446 get_prev_frame_1 (struct frame_info *this_frame)
1448 struct frame_id this_id;
1449 struct gdbarch *gdbarch;
1451 gdb_assert (this_frame != NULL);
1452 gdbarch = get_frame_arch (this_frame);
1456 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame_1 (this_frame=");
1457 if (this_frame != NULL)
1458 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
1460 fprintf_unfiltered (gdb_stdlog, "<NULL>");
1461 fprintf_unfiltered (gdb_stdlog, ") ");
1464 /* Only try to do the unwind once. */
1465 if (this_frame->prev_p)
1469 fprintf_unfiltered (gdb_stdlog, "-> ");
1470 fprint_frame (gdb_stdlog, this_frame->prev);
1471 fprintf_unfiltered (gdb_stdlog, " // cached \n");
1473 return this_frame->prev;
1476 /* If the frame unwinder hasn't been selected yet, we must do so
1477 before setting prev_p; otherwise the check for misbehaved
1478 sniffers will think that this frame's sniffer tried to unwind
1479 further (see frame_cleanup_after_sniffer). */
1480 if (this_frame->unwind == NULL)
1481 frame_unwind_find_by_frame (this_frame, &this_frame->prologue_cache);
1483 this_frame->prev_p = 1;
1484 this_frame->stop_reason = UNWIND_NO_REASON;
1486 /* If we are unwinding from an inline frame, all of the below tests
1487 were already performed when we unwound from the next non-inline
1488 frame. We must skip them, since we can not get THIS_FRAME's ID
1489 until we have unwound all the way down to the previous non-inline
1491 if (get_frame_type (this_frame) == INLINE_FRAME)
1492 return get_prev_frame_raw (this_frame);
1494 /* Check that this frame's ID was valid. If it wasn't, don't try to
1495 unwind to the prev frame. Be careful to not apply this test to
1496 the sentinel frame. */
1497 this_id = get_frame_id (this_frame);
1498 if (this_frame->level >= 0 && frame_id_eq (this_id, outer_frame_id))
1502 fprintf_unfiltered (gdb_stdlog, "-> ");
1503 fprint_frame (gdb_stdlog, NULL);
1504 fprintf_unfiltered (gdb_stdlog, " // this ID is NULL }\n");
1506 this_frame->stop_reason = UNWIND_NULL_ID;
1510 /* Check that this frame's ID isn't inner to (younger, below, next)
1511 the next frame. This happens when a frame unwind goes backwards.
1512 This check is valid only if this frame and the next frame are NORMAL.
1513 See the comment at frame_id_inner for details. */
1514 if (get_frame_type (this_frame) == NORMAL_FRAME
1515 && this_frame->next->unwind->type == NORMAL_FRAME
1516 && frame_id_inner (get_frame_arch (this_frame->next), this_id,
1517 get_frame_id (this_frame->next)))
1519 CORE_ADDR this_pc_in_block;
1520 struct minimal_symbol *morestack_msym;
1521 const char *morestack_name = NULL;
1523 /* gcc -fsplit-stack __morestack can continue the stack anywhere. */
1524 this_pc_in_block = get_frame_address_in_block (this_frame);
1525 morestack_msym = lookup_minimal_symbol_by_pc (this_pc_in_block);
1527 morestack_name = SYMBOL_LINKAGE_NAME (morestack_msym);
1528 if (!morestack_name || strcmp (morestack_name, "__morestack") != 0)
1532 fprintf_unfiltered (gdb_stdlog, "-> ");
1533 fprint_frame (gdb_stdlog, NULL);
1534 fprintf_unfiltered (gdb_stdlog,
1535 " // this frame ID is inner }\n");
1537 this_frame->stop_reason = UNWIND_INNER_ID;
1542 /* Check that this and the next frame are not identical. If they
1543 are, there is most likely a stack cycle. As with the inner-than
1544 test above, avoid comparing the inner-most and sentinel frames. */
1545 if (this_frame->level > 0
1546 && frame_id_eq (this_id, get_frame_id (this_frame->next)))
1550 fprintf_unfiltered (gdb_stdlog, "-> ");
1551 fprint_frame (gdb_stdlog, NULL);
1552 fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n");
1554 this_frame->stop_reason = UNWIND_SAME_ID;
1558 /* Check that this and the next frame do not unwind the PC register
1559 to the same memory location. If they do, then even though they
1560 have different frame IDs, the new frame will be bogus; two
1561 functions can't share a register save slot for the PC. This can
1562 happen when the prologue analyzer finds a stack adjustment, but
1565 This check does assume that the "PC register" is roughly a
1566 traditional PC, even if the gdbarch_unwind_pc method adjusts
1567 it (we do not rely on the value, only on the unwound PC being
1568 dependent on this value). A potential improvement would be
1569 to have the frame prev_pc method and the gdbarch unwind_pc
1570 method set the same lval and location information as
1571 frame_register_unwind. */
1572 if (this_frame->level > 0
1573 && gdbarch_pc_regnum (gdbarch) >= 0
1574 && get_frame_type (this_frame) == NORMAL_FRAME
1575 && (get_frame_type (this_frame->next) == NORMAL_FRAME
1576 || get_frame_type (this_frame->next) == INLINE_FRAME))
1578 int optimized, realnum, nrealnum;
1579 enum lval_type lval, nlval;
1580 CORE_ADDR addr, naddr;
1582 frame_register_unwind_location (this_frame,
1583 gdbarch_pc_regnum (gdbarch),
1584 &optimized, &lval, &addr, &realnum);
1585 frame_register_unwind_location (get_next_frame (this_frame),
1586 gdbarch_pc_regnum (gdbarch),
1587 &optimized, &nlval, &naddr, &nrealnum);
1589 if ((lval == lval_memory && lval == nlval && addr == naddr)
1590 || (lval == lval_register && lval == nlval && realnum == nrealnum))
1594 fprintf_unfiltered (gdb_stdlog, "-> ");
1595 fprint_frame (gdb_stdlog, NULL);
1596 fprintf_unfiltered (gdb_stdlog, " // no saved PC }\n");
1599 this_frame->stop_reason = UNWIND_NO_SAVED_PC;
1600 this_frame->prev = NULL;
1605 return get_prev_frame_raw (this_frame);
1608 /* Construct a new "struct frame_info" and link it previous to
1611 static struct frame_info *
1612 get_prev_frame_raw (struct frame_info *this_frame)
1614 struct frame_info *prev_frame;
1616 /* Allocate the new frame but do not wire it in to the frame chain.
1617 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
1618 frame->next to pull some fancy tricks (of course such code is, by
1619 definition, recursive). Try to prevent it.
1621 There is no reason to worry about memory leaks, should the
1622 remainder of the function fail. The allocated memory will be
1623 quickly reclaimed when the frame cache is flushed, and the `we've
1624 been here before' check above will stop repeated memory
1625 allocation calls. */
1626 prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
1627 prev_frame->level = this_frame->level + 1;
1629 /* For now, assume we don't have frame chains crossing address
1631 prev_frame->pspace = this_frame->pspace;
1632 prev_frame->aspace = this_frame->aspace;
1634 /* Don't yet compute ->unwind (and hence ->type). It is computed
1635 on-demand in get_frame_type, frame_register_unwind, and
1638 /* Don't yet compute the frame's ID. It is computed on-demand by
1641 /* The unwound frame ID is validate at the start of this function,
1642 as part of the logic to decide if that frame should be further
1643 unwound, and not here while the prev frame is being created.
1644 Doing this makes it possible for the user to examine a frame that
1645 has an invalid frame ID.
1647 Some very old VAX code noted: [...] For the sake of argument,
1648 suppose that the stack is somewhat trashed (which is one reason
1649 that "info frame" exists). So, return 0 (indicating we don't
1650 know the address of the arglist) if we don't know what frame this
1654 this_frame->prev = prev_frame;
1655 prev_frame->next = this_frame;
1659 fprintf_unfiltered (gdb_stdlog, "-> ");
1660 fprint_frame (gdb_stdlog, prev_frame);
1661 fprintf_unfiltered (gdb_stdlog, " }\n");
1667 /* Debug routine to print a NULL frame being returned. */
1670 frame_debug_got_null_frame (struct frame_info *this_frame,
1675 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame (this_frame=");
1676 if (this_frame != NULL)
1677 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
1679 fprintf_unfiltered (gdb_stdlog, "<NULL>");
1680 fprintf_unfiltered (gdb_stdlog, ") -> // %s}\n", reason);
1684 /* Is this (non-sentinel) frame in the "main"() function? */
1687 inside_main_func (struct frame_info *this_frame)
1689 struct minimal_symbol *msymbol;
1692 if (symfile_objfile == 0)
1694 msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
1695 if (msymbol == NULL)
1697 /* Make certain that the code, and not descriptor, address is
1699 maddr = gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame),
1700 SYMBOL_VALUE_ADDRESS (msymbol),
1702 return maddr == get_frame_func (this_frame);
1705 /* Test whether THIS_FRAME is inside the process entry point function. */
1708 inside_entry_func (struct frame_info *this_frame)
1710 CORE_ADDR entry_point;
1712 if (!entry_point_address_query (&entry_point))
1715 return get_frame_func (this_frame) == entry_point;
1718 /* Return a structure containing various interesting information about
1719 the frame that called THIS_FRAME. Returns NULL if there is entier
1720 no such frame or the frame fails any of a set of target-independent
1721 condition that should terminate the frame chain (e.g., as unwinding
1724 This function should not contain target-dependent tests, such as
1725 checking whether the program-counter is zero. */
1728 get_prev_frame (struct frame_info *this_frame)
1730 /* There is always a frame. If this assertion fails, suspect that
1731 something should be calling get_selected_frame() or
1732 get_current_frame(). */
1733 gdb_assert (this_frame != NULL);
1735 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
1736 sense to stop unwinding at a dummy frame. One place where a dummy
1737 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
1738 pcsqh register (space register for the instruction at the head of the
1739 instruction queue) cannot be written directly; the only way to set it
1740 is to branch to code that is in the target space. In order to implement
1741 frame dummies on HPUX, the called function is made to jump back to where
1742 the inferior was when the user function was called. If gdb was inside
1743 the main function when we created the dummy frame, the dummy frame will
1744 point inside the main function. */
1745 if (this_frame->level >= 0
1746 && get_frame_type (this_frame) == NORMAL_FRAME
1747 && !backtrace_past_main
1748 && inside_main_func (this_frame))
1749 /* Don't unwind past main(). Note, this is done _before_ the
1750 frame has been marked as previously unwound. That way if the
1751 user later decides to enable unwinds past main(), that will
1752 automatically happen. */
1754 frame_debug_got_null_frame (this_frame, "inside main func");
1758 /* If the user's backtrace limit has been exceeded, stop. We must
1759 add two to the current level; one of those accounts for backtrace_limit
1760 being 1-based and the level being 0-based, and the other accounts for
1761 the level of the new frame instead of the level of the current
1763 if (this_frame->level + 2 > backtrace_limit)
1765 frame_debug_got_null_frame (this_frame, "backtrace limit exceeded");
1769 /* If we're already inside the entry function for the main objfile,
1770 then it isn't valid. Don't apply this test to a dummy frame -
1771 dummy frame PCs typically land in the entry func. Don't apply
1772 this test to the sentinel frame. Sentinel frames should always
1773 be allowed to unwind. */
1774 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
1775 wasn't checking for "main" in the minimal symbols. With that
1776 fixed asm-source tests now stop in "main" instead of halting the
1777 backtrace in weird and wonderful ways somewhere inside the entry
1778 file. Suspect that tests for inside the entry file/func were
1779 added to work around that (now fixed) case. */
1780 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
1781 suggested having the inside_entry_func test use the
1782 inside_main_func() msymbol trick (along with entry_point_address()
1783 I guess) to determine the address range of the start function.
1784 That should provide a far better stopper than the current
1786 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
1787 applied tail-call optimizations to main so that a function called
1788 from main returns directly to the caller of main. Since we don't
1789 stop at main, we should at least stop at the entry point of the
1791 if (this_frame->level >= 0
1792 && get_frame_type (this_frame) == NORMAL_FRAME
1793 && !backtrace_past_entry
1794 && inside_entry_func (this_frame))
1796 frame_debug_got_null_frame (this_frame, "inside entry func");
1800 /* Assume that the only way to get a zero PC is through something
1801 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
1802 will never unwind a zero PC. */
1803 if (this_frame->level > 0
1804 && (get_frame_type (this_frame) == NORMAL_FRAME
1805 || get_frame_type (this_frame) == INLINE_FRAME)
1806 && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME
1807 && get_frame_pc (this_frame) == 0)
1809 frame_debug_got_null_frame (this_frame, "zero PC");
1813 return get_prev_frame_1 (this_frame);
1817 get_frame_pc (struct frame_info *frame)
1819 gdb_assert (frame->next != NULL);
1820 return frame_unwind_pc (frame->next);
1823 /* Return an address that falls within THIS_FRAME's code block. */
1826 get_frame_address_in_block (struct frame_info *this_frame)
1828 /* A draft address. */
1829 CORE_ADDR pc = get_frame_pc (this_frame);
1831 struct frame_info *next_frame = this_frame->next;
1833 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
1834 Normally the resume address is inside the body of the function
1835 associated with THIS_FRAME, but there is a special case: when
1836 calling a function which the compiler knows will never return
1837 (for instance abort), the call may be the very last instruction
1838 in the calling function. The resume address will point after the
1839 call and may be at the beginning of a different function
1842 If THIS_FRAME is a signal frame or dummy frame, then we should
1843 not adjust the unwound PC. For a dummy frame, GDB pushed the
1844 resume address manually onto the stack. For a signal frame, the
1845 OS may have pushed the resume address manually and invoked the
1846 handler (e.g. GNU/Linux), or invoked the trampoline which called
1847 the signal handler - but in either case the signal handler is
1848 expected to return to the trampoline. So in both of these
1849 cases we know that the resume address is executable and
1850 related. So we only need to adjust the PC if THIS_FRAME
1851 is a normal function.
1853 If the program has been interrupted while THIS_FRAME is current,
1854 then clearly the resume address is inside the associated
1855 function. There are three kinds of interruption: debugger stop
1856 (next frame will be SENTINEL_FRAME), operating system
1857 signal or exception (next frame will be SIGTRAMP_FRAME),
1858 or debugger-induced function call (next frame will be
1859 DUMMY_FRAME). So we only need to adjust the PC if
1860 NEXT_FRAME is a normal function.
1862 We check the type of NEXT_FRAME first, since it is already
1863 known; frame type is determined by the unwinder, and since
1864 we have THIS_FRAME we've already selected an unwinder for
1867 If the next frame is inlined, we need to keep going until we find
1868 the real function - for instance, if a signal handler is invoked
1869 while in an inlined function, then the code address of the
1870 "calling" normal function should not be adjusted either. */
1872 while (get_frame_type (next_frame) == INLINE_FRAME)
1873 next_frame = next_frame->next;
1875 if (get_frame_type (next_frame) == NORMAL_FRAME
1876 && (get_frame_type (this_frame) == NORMAL_FRAME
1877 || get_frame_type (this_frame) == INLINE_FRAME))
1884 find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal)
1886 struct frame_info *next_frame;
1889 /* If the next frame represents an inlined function call, this frame's
1890 sal is the "call site" of that inlined function, which can not
1891 be inferred from get_frame_pc. */
1892 next_frame = get_next_frame (frame);
1893 if (frame_inlined_callees (frame) > 0)
1898 sym = get_frame_function (next_frame);
1900 sym = inline_skipped_symbol (inferior_ptid);
1902 /* If frame is inline, it certainly has symbols. */
1905 if (SYMBOL_LINE (sym) != 0)
1907 sal->symtab = SYMBOL_SYMTAB (sym);
1908 sal->line = SYMBOL_LINE (sym);
1911 /* If the symbol does not have a location, we don't know where
1912 the call site is. Do not pretend to. This is jarring, but
1913 we can't do much better. */
1914 sal->pc = get_frame_pc (frame);
1919 /* If FRAME is not the innermost frame, that normally means that
1920 FRAME->pc points at the return instruction (which is *after* the
1921 call instruction), and we want to get the line containing the
1922 call (because the call is where the user thinks the program is).
1923 However, if the next frame is either a SIGTRAMP_FRAME or a
1924 DUMMY_FRAME, then the next frame will contain a saved interrupt
1925 PC and such a PC indicates the current (rather than next)
1926 instruction/line, consequently, for such cases, want to get the
1927 line containing fi->pc. */
1928 notcurrent = (get_frame_pc (frame) != get_frame_address_in_block (frame));
1929 (*sal) = find_pc_line (get_frame_pc (frame), notcurrent);
1932 /* Per "frame.h", return the ``address'' of the frame. Code should
1933 really be using get_frame_id(). */
1935 get_frame_base (struct frame_info *fi)
1937 return get_frame_id (fi).stack_addr;
1940 /* High-level offsets into the frame. Used by the debug info. */
1943 get_frame_base_address (struct frame_info *fi)
1945 if (get_frame_type (fi) != NORMAL_FRAME)
1947 if (fi->base == NULL)
1948 fi->base = frame_base_find_by_frame (fi);
1949 /* Sneaky: If the low-level unwind and high-level base code share a
1950 common unwinder, let them share the prologue cache. */
1951 if (fi->base->unwind == fi->unwind)
1952 return fi->base->this_base (fi, &fi->prologue_cache);
1953 return fi->base->this_base (fi, &fi->base_cache);
1957 get_frame_locals_address (struct frame_info *fi)
1959 if (get_frame_type (fi) != NORMAL_FRAME)
1961 /* If there isn't a frame address method, find it. */
1962 if (fi->base == NULL)
1963 fi->base = frame_base_find_by_frame (fi);
1964 /* Sneaky: If the low-level unwind and high-level base code share a
1965 common unwinder, let them share the prologue cache. */
1966 if (fi->base->unwind == fi->unwind)
1967 return fi->base->this_locals (fi, &fi->prologue_cache);
1968 return fi->base->this_locals (fi, &fi->base_cache);
1972 get_frame_args_address (struct frame_info *fi)
1974 if (get_frame_type (fi) != NORMAL_FRAME)
1976 /* If there isn't a frame address method, find it. */
1977 if (fi->base == NULL)
1978 fi->base = frame_base_find_by_frame (fi);
1979 /* Sneaky: If the low-level unwind and high-level base code share a
1980 common unwinder, let them share the prologue cache. */
1981 if (fi->base->unwind == fi->unwind)
1982 return fi->base->this_args (fi, &fi->prologue_cache);
1983 return fi->base->this_args (fi, &fi->base_cache);
1986 /* Return true if the frame unwinder for frame FI is UNWINDER; false
1990 frame_unwinder_is (struct frame_info *fi, const struct frame_unwind *unwinder)
1992 if (fi->unwind == NULL)
1993 frame_unwind_find_by_frame (fi, &fi->prologue_cache);
1994 return fi->unwind == unwinder;
1997 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
1998 or -1 for a NULL frame. */
2001 frame_relative_level (struct frame_info *fi)
2010 get_frame_type (struct frame_info *frame)
2012 if (frame->unwind == NULL)
2013 /* Initialize the frame's unwinder because that's what
2014 provides the frame's type. */
2015 frame_unwind_find_by_frame (frame, &frame->prologue_cache);
2016 return frame->unwind->type;
2019 struct program_space *
2020 get_frame_program_space (struct frame_info *frame)
2022 return frame->pspace;
2025 struct program_space *
2026 frame_unwind_program_space (struct frame_info *this_frame)
2028 gdb_assert (this_frame);
2030 /* This is really a placeholder to keep the API consistent --- we
2031 assume for now that we don't have frame chains crossing
2033 return this_frame->pspace;
2036 struct address_space *
2037 get_frame_address_space (struct frame_info *frame)
2039 return frame->aspace;
2042 /* Memory access methods. */
2045 get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr,
2046 gdb_byte *buf, int len)
2048 read_memory (addr, buf, len);
2052 get_frame_memory_signed (struct frame_info *this_frame, CORE_ADDR addr,
2055 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2056 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2058 return read_memory_integer (addr, len, byte_order);
2062 get_frame_memory_unsigned (struct frame_info *this_frame, CORE_ADDR addr,
2065 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2066 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
2068 return read_memory_unsigned_integer (addr, len, byte_order);
2072 safe_frame_unwind_memory (struct frame_info *this_frame,
2073 CORE_ADDR addr, gdb_byte *buf, int len)
2075 /* NOTE: target_read_memory returns zero on success! */
2076 return !target_read_memory (addr, buf, len);
2079 /* Architecture methods. */
2082 get_frame_arch (struct frame_info *this_frame)
2084 return frame_unwind_arch (this_frame->next);
2088 frame_unwind_arch (struct frame_info *next_frame)
2090 if (!next_frame->prev_arch.p)
2092 struct gdbarch *arch;
2094 if (next_frame->unwind == NULL)
2095 frame_unwind_find_by_frame (next_frame, &next_frame->prologue_cache);
2097 if (next_frame->unwind->prev_arch != NULL)
2098 arch = next_frame->unwind->prev_arch (next_frame,
2099 &next_frame->prologue_cache);
2101 arch = get_frame_arch (next_frame);
2103 next_frame->prev_arch.arch = arch;
2104 next_frame->prev_arch.p = 1;
2106 fprintf_unfiltered (gdb_stdlog,
2107 "{ frame_unwind_arch (next_frame=%d) -> %s }\n",
2109 gdbarch_bfd_arch_info (arch)->printable_name);
2112 return next_frame->prev_arch.arch;
2116 frame_unwind_caller_arch (struct frame_info *next_frame)
2118 return frame_unwind_arch (skip_inlined_frames (next_frame));
2121 /* Stack pointer methods. */
2124 get_frame_sp (struct frame_info *this_frame)
2126 struct gdbarch *gdbarch = get_frame_arch (this_frame);
2128 /* Normality - an architecture that provides a way of obtaining any
2129 frame inner-most address. */
2130 if (gdbarch_unwind_sp_p (gdbarch))
2131 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
2132 operate on THIS_FRAME now. */
2133 return gdbarch_unwind_sp (gdbarch, this_frame->next);
2134 /* Now things are really are grim. Hope that the value returned by
2135 the gdbarch_sp_regnum register is meaningful. */
2136 if (gdbarch_sp_regnum (gdbarch) >= 0)
2137 return get_frame_register_unsigned (this_frame,
2138 gdbarch_sp_regnum (gdbarch));
2139 internal_error (__FILE__, __LINE__, _("Missing unwind SP method"));
2142 /* Return the reason why we can't unwind past FRAME. */
2144 enum unwind_stop_reason
2145 get_frame_unwind_stop_reason (struct frame_info *frame)
2147 /* If we haven't tried to unwind past this point yet, then assume
2148 that unwinding would succeed. */
2149 if (frame->prev_p == 0)
2150 return UNWIND_NO_REASON;
2152 /* Otherwise, we set a reason when we succeeded (or failed) to
2154 return frame->stop_reason;
2157 /* Return a string explaining REASON. */
2160 frame_stop_reason_string (enum unwind_stop_reason reason)
2164 case UNWIND_NULL_ID:
2165 return _("unwinder did not report frame ID");
2167 case UNWIND_INNER_ID:
2168 return _("previous frame inner to this frame (corrupt stack?)");
2170 case UNWIND_SAME_ID:
2171 return _("previous frame identical to this frame (corrupt stack?)");
2173 case UNWIND_NO_SAVED_PC:
2174 return _("frame did not save the PC");
2176 case UNWIND_NO_REASON:
2177 case UNWIND_FIRST_ERROR:
2179 internal_error (__FILE__, __LINE__,
2180 "Invalid frame stop reason");
2184 /* Clean up after a failed (wrong unwinder) attempt to unwind past
2188 frame_cleanup_after_sniffer (void *arg)
2190 struct frame_info *frame = arg;
2192 /* The sniffer should not allocate a prologue cache if it did not
2193 match this frame. */
2194 gdb_assert (frame->prologue_cache == NULL);
2196 /* No sniffer should extend the frame chain; sniff based on what is
2198 gdb_assert (!frame->prev_p);
2200 /* The sniffer should not check the frame's ID; that's circular. */
2201 gdb_assert (!frame->this_id.p);
2203 /* Clear cached fields dependent on the unwinder.
2205 The previous PC is independent of the unwinder, but the previous
2206 function is not (see get_frame_address_in_block). */
2207 frame->prev_func.p = 0;
2208 frame->prev_func.addr = 0;
2210 /* Discard the unwinder last, so that we can easily find it if an assertion
2211 in this function triggers. */
2212 frame->unwind = NULL;
2215 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
2216 Return a cleanup which should be called if unwinding fails, and
2217 discarded if it succeeds. */
2220 frame_prepare_for_sniffer (struct frame_info *frame,
2221 const struct frame_unwind *unwind)
2223 gdb_assert (frame->unwind == NULL);
2224 frame->unwind = unwind;
2225 return make_cleanup (frame_cleanup_after_sniffer, frame);
2228 extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */
2230 static struct cmd_list_element *set_backtrace_cmdlist;
2231 static struct cmd_list_element *show_backtrace_cmdlist;
2234 set_backtrace_cmd (char *args, int from_tty)
2236 help_list (set_backtrace_cmdlist, "set backtrace ", -1, gdb_stdout);
2240 show_backtrace_cmd (char *args, int from_tty)
2242 cmd_show_list (show_backtrace_cmdlist, from_tty, "");
2246 _initialize_frame (void)
2248 obstack_init (&frame_cache_obstack);
2250 observer_attach_target_changed (frame_observer_target_changed);
2252 add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, _("\
2253 Set backtrace specific variables.\n\
2254 Configure backtrace variables such as the backtrace limit"),
2255 &set_backtrace_cmdlist, "set backtrace ",
2256 0/*allow-unknown*/, &setlist);
2257 add_prefix_cmd ("backtrace", class_maintenance, show_backtrace_cmd, _("\
2258 Show backtrace specific variables\n\
2259 Show backtrace variables such as the backtrace limit"),
2260 &show_backtrace_cmdlist, "show backtrace ",
2261 0/*allow-unknown*/, &showlist);
2263 add_setshow_boolean_cmd ("past-main", class_obscure,
2264 &backtrace_past_main, _("\
2265 Set whether backtraces should continue past \"main\"."), _("\
2266 Show whether backtraces should continue past \"main\"."), _("\
2267 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
2268 the backtrace at \"main\". Set this variable if you need to see the rest\n\
2269 of the stack trace."),
2271 show_backtrace_past_main,
2272 &set_backtrace_cmdlist,
2273 &show_backtrace_cmdlist);
2275 add_setshow_boolean_cmd ("past-entry", class_obscure,
2276 &backtrace_past_entry, _("\
2277 Set whether backtraces should continue past the entry point of a program."),
2279 Show whether backtraces should continue past the entry point of a program."),
2281 Normally there are no callers beyond the entry point of a program, so GDB\n\
2282 will terminate the backtrace there. Set this variable if you need to see\n\
2283 the rest of the stack trace."),
2285 show_backtrace_past_entry,
2286 &set_backtrace_cmdlist,
2287 &show_backtrace_cmdlist);
2289 add_setshow_integer_cmd ("limit", class_obscure,
2290 &backtrace_limit, _("\
2291 Set an upper bound on the number of backtrace levels."), _("\
2292 Show the upper bound on the number of backtrace levels."), _("\
2293 No more than the specified number of frames can be displayed or examined.\n\
2294 Zero is unlimited."),
2296 show_backtrace_limit,
2297 &set_backtrace_cmdlist,
2298 &show_backtrace_cmdlist);
2300 /* Debug this files internals. */
2301 add_setshow_zinteger_cmd ("frame", class_maintenance, &frame_debug, _("\
2302 Set frame debugging."), _("\
2303 Show frame debugging."), _("\
2304 When non-zero, frame specific internal debugging is enabled."),
2307 &setdebuglist, &showdebuglist);