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 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 static struct frame_info *get_prev_frame_1 (struct frame_info *this_frame);
47 /* We keep a cache of stack frames, each of which is a "struct
48 frame_info". The innermost one gets allocated (in
49 wait_for_inferior) each time the inferior stops; current_frame
50 points to it. Additional frames get allocated (in get_prev_frame)
51 as needed, and are chained through the next and prev fields. Any
52 time that the frame cache becomes invalid (most notably when we
53 execute something, but also if we change how we interpret the
54 frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything
55 which reads new symbols)), we should call reinit_frame_cache. */
59 /* Level of this frame. The inner-most (youngest) frame is at level
60 0. As you move towards the outer-most (oldest) frame, the level
61 increases. This is a cached value. It could just as easily be
62 computed by counting back from the selected frame to the inner
64 /* NOTE: cagney/2002-04-05: Perhaps a level of ``-1'' should be
65 reserved to indicate a bogus frame - one that has been created
66 just to keep GDB happy (GDB always needs a frame). For the
67 moment leave this as speculation. */
70 /* The frame's low-level unwinder and corresponding cache. The
71 low-level unwinder is responsible for unwinding register values
72 for the previous frame. The low-level unwind methods are
73 selected based on the presence, or otherwise, of register unwind
74 information such as CFI. */
76 const struct frame_unwind *unwind;
78 /* Cached copy of the previous frame's resume address. */
84 /* Cached copy of the previous frame's function address. */
91 /* This frame's ID. */
95 struct frame_id value;
98 /* The frame's high-level base methods, and corresponding cache.
99 The high level base methods are selected based on the frame's
101 const struct frame_base *base;
104 /* Pointers to the next (down, inner, younger) and previous (up,
105 outer, older) frame_info's in the frame cache. */
106 struct frame_info *next; /* down, inner, younger */
108 struct frame_info *prev; /* up, outer, older */
110 /* The reason why we could not set PREV, or UNWIND_NO_REASON if we
111 could. Only valid when PREV_P is set. */
112 enum unwind_stop_reason stop_reason;
115 /* Flag to control debugging. */
119 show_frame_debug (struct ui_file *file, int from_tty,
120 struct cmd_list_element *c, const char *value)
122 fprintf_filtered (file, _("Frame debugging is %s.\n"), value);
125 /* Flag to indicate whether backtraces should stop at main et.al. */
127 static int backtrace_past_main;
129 show_backtrace_past_main (struct ui_file *file, int from_tty,
130 struct cmd_list_element *c, const char *value)
132 fprintf_filtered (file, _("\
133 Whether backtraces should continue past \"main\" is %s.\n"),
137 static int backtrace_past_entry;
139 show_backtrace_past_entry (struct ui_file *file, int from_tty,
140 struct cmd_list_element *c, const char *value)
142 fprintf_filtered (file, _("\
143 Whether backtraces should continue past the entry point of a program is %s.\n"),
147 static int backtrace_limit = INT_MAX;
149 show_backtrace_limit (struct ui_file *file, int from_tty,
150 struct cmd_list_element *c, const char *value)
152 fprintf_filtered (file, _("\
153 An upper bound on the number of backtrace levels is %s.\n"),
159 fprint_field (struct ui_file *file, const char *name, int p, CORE_ADDR addr)
162 fprintf_unfiltered (file, "%s=0x%s", name, paddr_nz (addr));
164 fprintf_unfiltered (file, "!%s", name);
168 fprint_frame_id (struct ui_file *file, struct frame_id id)
170 fprintf_unfiltered (file, "{");
171 fprint_field (file, "stack", id.stack_addr_p, id.stack_addr);
172 fprintf_unfiltered (file, ",");
173 fprint_field (file, "code", id.code_addr_p, id.code_addr);
174 fprintf_unfiltered (file, ",");
175 fprint_field (file, "special", id.special_addr_p, id.special_addr);
176 fprintf_unfiltered (file, "}");
180 fprint_frame_type (struct ui_file *file, enum frame_type type)
185 fprintf_unfiltered (file, "NORMAL_FRAME");
188 fprintf_unfiltered (file, "DUMMY_FRAME");
191 fprintf_unfiltered (file, "SIGTRAMP_FRAME");
194 fprintf_unfiltered (file, "<unknown type>");
200 fprint_frame (struct ui_file *file, struct frame_info *fi)
204 fprintf_unfiltered (file, "<NULL frame>");
207 fprintf_unfiltered (file, "{");
208 fprintf_unfiltered (file, "level=%d", fi->level);
209 fprintf_unfiltered (file, ",");
210 fprintf_unfiltered (file, "type=");
211 if (fi->unwind != NULL)
212 fprint_frame_type (file, fi->unwind->type);
214 fprintf_unfiltered (file, "<unknown>");
215 fprintf_unfiltered (file, ",");
216 fprintf_unfiltered (file, "unwind=");
217 if (fi->unwind != NULL)
218 gdb_print_host_address (fi->unwind, file);
220 fprintf_unfiltered (file, "<unknown>");
221 fprintf_unfiltered (file, ",");
222 fprintf_unfiltered (file, "pc=");
223 if (fi->next != NULL && fi->next->prev_pc.p)
224 fprintf_unfiltered (file, "0x%s", paddr_nz (fi->next->prev_pc.value));
226 fprintf_unfiltered (file, "<unknown>");
227 fprintf_unfiltered (file, ",");
228 fprintf_unfiltered (file, "id=");
230 fprint_frame_id (file, fi->this_id.value);
232 fprintf_unfiltered (file, "<unknown>");
233 fprintf_unfiltered (file, ",");
234 fprintf_unfiltered (file, "func=");
235 if (fi->next != NULL && fi->next->prev_func.p)
236 fprintf_unfiltered (file, "0x%s", paddr_nz (fi->next->prev_func.addr));
238 fprintf_unfiltered (file, "<unknown>");
239 fprintf_unfiltered (file, "}");
242 /* Return a frame uniq ID that can be used to, later, re-find the
246 get_frame_id (struct frame_info *fi)
250 return null_frame_id;
255 fprintf_unfiltered (gdb_stdlog, "{ get_frame_id (fi=%d) ",
257 /* Find the unwinder. */
258 if (fi->unwind == NULL)
259 fi->unwind = frame_unwind_find_by_frame (fi, &fi->prologue_cache);
260 /* Find THIS frame's ID. */
261 fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value);
265 fprintf_unfiltered (gdb_stdlog, "-> ");
266 fprint_frame_id (gdb_stdlog, fi->this_id.value);
267 fprintf_unfiltered (gdb_stdlog, " }\n");
270 return fi->this_id.value;
274 frame_unwind_id (struct frame_info *next_frame)
276 /* Use prev_frame, and not get_prev_frame. The latter will truncate
277 the frame chain, leading to this function unintentionally
278 returning a null_frame_id (e.g., when a caller requests the frame
279 ID of "main()"s caller. */
280 return get_frame_id (get_prev_frame_1 (next_frame));
283 const struct frame_id null_frame_id; /* All zeros. */
286 frame_id_build_special (CORE_ADDR stack_addr, CORE_ADDR code_addr,
287 CORE_ADDR special_addr)
289 struct frame_id id = null_frame_id;
290 id.stack_addr = stack_addr;
292 id.code_addr = code_addr;
294 id.special_addr = special_addr;
295 id.special_addr_p = 1;
300 frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr)
302 struct frame_id id = null_frame_id;
303 id.stack_addr = stack_addr;
305 id.code_addr = code_addr;
311 frame_id_build_wild (CORE_ADDR stack_addr)
313 struct frame_id id = null_frame_id;
314 id.stack_addr = stack_addr;
320 frame_id_p (struct frame_id l)
323 /* The frame is valid iff it has a valid stack address. */
327 fprintf_unfiltered (gdb_stdlog, "{ frame_id_p (l=");
328 fprint_frame_id (gdb_stdlog, l);
329 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", p);
335 frame_id_eq (struct frame_id l, struct frame_id r)
338 if (!l.stack_addr_p || !r.stack_addr_p)
339 /* Like a NaN, if either ID is invalid, the result is false.
340 Note that a frame ID is invalid iff it is the null frame ID. */
342 else if (l.stack_addr != r.stack_addr)
343 /* If .stack addresses are different, the frames are different. */
345 else if (!l.code_addr_p || !r.code_addr_p)
346 /* An invalid code addr is a wild card, always succeed. */
348 else if (l.code_addr != r.code_addr)
349 /* If .code addresses are different, the frames are different. */
351 else if (!l.special_addr_p || !r.special_addr_p)
352 /* An invalid special addr is a wild card (or unused), always succeed. */
354 else if (l.special_addr == r.special_addr)
355 /* Frames are equal. */
362 fprintf_unfiltered (gdb_stdlog, "{ frame_id_eq (l=");
363 fprint_frame_id (gdb_stdlog, l);
364 fprintf_unfiltered (gdb_stdlog, ",r=");
365 fprint_frame_id (gdb_stdlog, r);
366 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", eq);
371 /* Safety net to check whether frame ID L should be inner to
372 frame ID R, according to their stack addresses.
374 This method cannot be used to compare arbitrary frames, as the
375 ranges of valid stack addresses may be discontiguous (e.g. due
378 However, it can be used as safety net to discover invalid frame
379 IDs in certain circumstances.
381 * If frame NEXT is the immediate inner frame to THIS, and NEXT
382 is a NORMAL frame, then the stack address of NEXT must be
383 inner-than-or-equal to the stack address of THIS.
385 Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind
388 * If frame NEXT is the immediate inner frame to THIS, and NEXT
389 is a NORMAL frame, and NEXT and THIS have different stack
390 addresses, no other frame in the frame chain may have a stack
393 Therefore, if frame_id_inner (TEST, THIS) holds, but
394 frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer
395 to a valid frame in the frame chain. */
398 frame_id_inner (struct gdbarch *gdbarch, struct frame_id l, struct frame_id r)
401 if (!l.stack_addr_p || !r.stack_addr_p)
402 /* Like NaN, any operation involving an invalid ID always fails. */
405 /* Only return non-zero when strictly inner than. Note that, per
406 comment in "frame.h", there is some fuzz here. Frameless
407 functions are not strictly inner than (same .stack but
408 different .code and/or .special address). */
409 inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr);
412 fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l=");
413 fprint_frame_id (gdb_stdlog, l);
414 fprintf_unfiltered (gdb_stdlog, ",r=");
415 fprint_frame_id (gdb_stdlog, r);
416 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", inner);
422 frame_find_by_id (struct frame_id id)
424 struct frame_info *frame, *prev_frame;
426 /* ZERO denotes the null frame, let the caller decide what to do
427 about it. Should it instead return get_current_frame()? */
428 if (!frame_id_p (id))
431 for (frame = get_current_frame (); ; frame = prev_frame)
433 struct frame_id this = get_frame_id (frame);
434 if (frame_id_eq (id, this))
435 /* An exact match. */
438 prev_frame = get_prev_frame (frame);
442 /* As a safety net to avoid unnecessary backtracing while trying
443 to find an invalid ID, we check for a common situation where
444 we can detect from comparing stack addresses that no other
445 frame in the current frame chain can have this ID. See the
446 comment at frame_id_inner for details. */
447 if (get_frame_type (frame) == NORMAL_FRAME
448 && !frame_id_inner (get_frame_arch (frame), id, this)
449 && frame_id_inner (get_frame_arch (prev_frame), id,
450 get_frame_id (prev_frame)))
457 frame_pc_unwind (struct frame_info *this_frame)
459 if (!this_frame->prev_pc.p)
462 if (gdbarch_unwind_pc_p (get_frame_arch (this_frame)))
464 /* The right way. The `pure' way. The one true way. This
465 method depends solely on the register-unwind code to
466 determine the value of registers in THIS frame, and hence
467 the value of this frame's PC (resume address). A typical
468 implementation is no more than:
470 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf);
471 return extract_unsigned_integer (buf, size of ISA_PC_REGNUM);
473 Note: this method is very heavily dependent on a correct
474 register-unwind implementation, it pays to fix that
475 method first; this method is frame type agnostic, since
476 it only deals with register values, it works with any
477 frame. This is all in stark contrast to the old
478 FRAME_SAVED_PC which would try to directly handle all the
479 different ways that a PC could be unwound. */
480 pc = gdbarch_unwind_pc (get_frame_arch (this_frame), this_frame);
483 internal_error (__FILE__, __LINE__, _("No unwind_pc method"));
484 this_frame->prev_pc.value = pc;
485 this_frame->prev_pc.p = 1;
487 fprintf_unfiltered (gdb_stdlog,
488 "{ frame_pc_unwind (this_frame=%d) -> 0x%s }\n",
490 paddr_nz (this_frame->prev_pc.value));
492 return this_frame->prev_pc.value;
496 get_frame_func (struct frame_info *this_frame)
498 struct frame_info *next_frame = this_frame->next;
500 if (!next_frame->prev_func.p)
502 /* Make certain that this, and not the adjacent, function is
504 CORE_ADDR addr_in_block = get_frame_address_in_block (this_frame);
505 next_frame->prev_func.p = 1;
506 next_frame->prev_func.addr = get_pc_function_start (addr_in_block);
508 fprintf_unfiltered (gdb_stdlog,
509 "{ get_frame_func (this_frame=%d) -> 0x%s }\n",
511 paddr_nz (next_frame->prev_func.addr));
513 return next_frame->prev_func.addr;
517 do_frame_register_read (void *src, int regnum, gdb_byte *buf)
519 return frame_register_read (src, regnum, buf);
523 frame_save_as_regcache (struct frame_info *this_frame)
525 struct regcache *regcache = regcache_xmalloc (get_frame_arch (this_frame));
526 struct cleanup *cleanups = make_cleanup_regcache_xfree (regcache);
527 regcache_save (regcache, do_frame_register_read, this_frame);
528 discard_cleanups (cleanups);
533 frame_pop (struct frame_info *this_frame)
535 struct frame_info *prev_frame;
536 struct regcache *scratch;
537 struct cleanup *cleanups;
539 /* Ensure that we have a frame to pop to. */
540 prev_frame = get_prev_frame_1 (this_frame);
543 error (_("Cannot pop the initial frame."));
545 /* Make a copy of all the register values unwound from this frame.
546 Save them in a scratch buffer so that there isn't a race between
547 trying to extract the old values from the current regcache while
548 at the same time writing new values into that same cache. */
549 scratch = frame_save_as_regcache (prev_frame);
550 cleanups = make_cleanup_regcache_xfree (scratch);
552 /* If we are popping a dummy frame, clean up the associated
554 if (get_frame_type (this_frame) == DUMMY_FRAME)
555 dummy_frame_pop (get_frame_id (this_frame));
557 /* FIXME: cagney/2003-03-16: It should be possible to tell the
558 target's register cache that it is about to be hit with a burst
559 register transfer and that the sequence of register writes should
560 be batched. The pair target_prepare_to_store() and
561 target_store_registers() kind of suggest this functionality.
562 Unfortunately, they don't implement it. Their lack of a formal
563 definition can lead to targets writing back bogus values
564 (arguably a bug in the target code mind). */
565 /* Now copy those saved registers into the current regcache.
566 Here, regcache_cpy() calls regcache_restore(). */
567 regcache_cpy (get_current_regcache (), scratch);
568 do_cleanups (cleanups);
570 /* We've made right mess of GDB's local state, just discard
572 reinit_frame_cache ();
576 frame_register_unwind (struct frame_info *frame, int regnum,
577 int *optimizedp, enum lval_type *lvalp,
578 CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp)
582 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
583 that the value proper does not need to be fetched. */
584 gdb_assert (optimizedp != NULL);
585 gdb_assert (lvalp != NULL);
586 gdb_assert (addrp != NULL);
587 gdb_assert (realnump != NULL);
588 /* gdb_assert (bufferp != NULL); */
590 value = frame_unwind_register_value (frame, regnum);
592 gdb_assert (value != NULL);
594 *optimizedp = value_optimized_out (value);
595 *lvalp = VALUE_LVAL (value);
596 *addrp = VALUE_ADDRESS (value);
597 *realnump = VALUE_REGNUM (value);
600 memcpy (bufferp, value_contents_all (value),
601 TYPE_LENGTH (value_type (value)));
603 /* Dispose of the new value. This prevents watchpoints from
604 trying to watch the saved frame pointer. */
605 release_value (value);
610 frame_register (struct frame_info *frame, int regnum,
611 int *optimizedp, enum lval_type *lvalp,
612 CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp)
614 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
615 that the value proper does not need to be fetched. */
616 gdb_assert (optimizedp != NULL);
617 gdb_assert (lvalp != NULL);
618 gdb_assert (addrp != NULL);
619 gdb_assert (realnump != NULL);
620 /* gdb_assert (bufferp != NULL); */
622 /* Obtain the register value by unwinding the register from the next
623 (more inner frame). */
624 gdb_assert (frame != NULL && frame->next != NULL);
625 frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
630 frame_unwind_register (struct frame_info *frame, int regnum, gdb_byte *buf)
636 frame_register_unwind (frame, regnum, &optimized, &lval, &addr,
641 get_frame_register (struct frame_info *frame,
642 int regnum, gdb_byte *buf)
644 frame_unwind_register (frame->next, regnum, buf);
648 frame_unwind_register_value (struct frame_info *frame, int regnum)
652 gdb_assert (frame != NULL);
656 fprintf_unfiltered (gdb_stdlog, "\
657 { frame_unwind_register_value (frame=%d,regnum=%d(%s),...) ",
658 frame->level, regnum,
659 user_reg_map_regnum_to_name
660 (get_frame_arch (frame), regnum));
663 /* Find the unwinder. */
664 if (frame->unwind == NULL)
665 frame->unwind = frame_unwind_find_by_frame (frame, &frame->prologue_cache);
667 /* Ask this frame to unwind its register. */
668 value = frame->unwind->prev_register (frame, &frame->prologue_cache, regnum);
672 fprintf_unfiltered (gdb_stdlog, "->");
673 if (value_optimized_out (value))
674 fprintf_unfiltered (gdb_stdlog, " optimized out");
677 if (VALUE_LVAL (value) == lval_register)
678 fprintf_unfiltered (gdb_stdlog, " register=%d",
679 VALUE_REGNUM (value));
680 else if (VALUE_LVAL (value) == lval_memory)
681 fprintf_unfiltered (gdb_stdlog, " address=0x%s",
682 paddr_nz (VALUE_ADDRESS (value)));
684 fprintf_unfiltered (gdb_stdlog, " computed");
686 if (value_lazy (value))
687 fprintf_unfiltered (gdb_stdlog, " lazy");
691 const gdb_byte *buf = value_contents (value);
693 fprintf_unfiltered (gdb_stdlog, " bytes=");
694 fprintf_unfiltered (gdb_stdlog, "[");
695 for (i = 0; i < register_size (get_frame_arch (frame), regnum); i++)
696 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
697 fprintf_unfiltered (gdb_stdlog, "]");
701 fprintf_unfiltered (gdb_stdlog, " }\n");
708 get_frame_register_value (struct frame_info *frame, int regnum)
710 return frame_unwind_register_value (frame->next, regnum);
714 frame_unwind_register_signed (struct frame_info *frame, int regnum)
716 gdb_byte buf[MAX_REGISTER_SIZE];
717 frame_unwind_register (frame, regnum, buf);
718 return extract_signed_integer (buf, register_size (get_frame_arch (frame),
723 get_frame_register_signed (struct frame_info *frame, int regnum)
725 return frame_unwind_register_signed (frame->next, regnum);
729 frame_unwind_register_unsigned (struct frame_info *frame, int regnum)
731 gdb_byte buf[MAX_REGISTER_SIZE];
732 frame_unwind_register (frame, regnum, buf);
733 return extract_unsigned_integer (buf, register_size (get_frame_arch (frame),
738 get_frame_register_unsigned (struct frame_info *frame, int regnum)
740 return frame_unwind_register_unsigned (frame->next, regnum);
744 put_frame_register (struct frame_info *frame, int regnum,
747 struct gdbarch *gdbarch = get_frame_arch (frame);
752 frame_register (frame, regnum, &optim, &lval, &addr, &realnum, NULL);
754 error (_("Attempt to assign to a value that was optimized out."));
759 /* FIXME: write_memory doesn't yet take constant buffers.
761 gdb_byte tmp[MAX_REGISTER_SIZE];
762 memcpy (tmp, buf, register_size (gdbarch, regnum));
763 write_memory (addr, tmp, register_size (gdbarch, regnum));
767 regcache_cooked_write (get_current_regcache (), realnum, buf);
770 error (_("Attempt to assign to an unmodifiable value."));
774 /* frame_register_read ()
776 Find and return the value of REGNUM for the specified stack frame.
777 The number of bytes copied is REGISTER_SIZE (REGNUM).
779 Returns 0 if the register value could not be found. */
782 frame_register_read (struct frame_info *frame, int regnum,
789 frame_register (frame, regnum, &optimized, &lval, &addr, &realnum, myaddr);
795 get_frame_register_bytes (struct frame_info *frame, int regnum,
796 CORE_ADDR offset, int len, gdb_byte *myaddr)
798 struct gdbarch *gdbarch = get_frame_arch (frame);
800 /* Skip registers wholly inside of OFFSET. */
801 while (offset >= register_size (gdbarch, regnum))
803 offset -= register_size (gdbarch, regnum);
810 int curr_len = register_size (gdbarch, regnum) - offset;
814 if (curr_len == register_size (gdbarch, regnum))
816 if (!frame_register_read (frame, regnum, myaddr))
821 gdb_byte buf[MAX_REGISTER_SIZE];
822 if (!frame_register_read (frame, regnum, buf))
824 memcpy (myaddr, buf + offset, curr_len);
837 put_frame_register_bytes (struct frame_info *frame, int regnum,
838 CORE_ADDR offset, int len, const gdb_byte *myaddr)
840 struct gdbarch *gdbarch = get_frame_arch (frame);
842 /* Skip registers wholly inside of OFFSET. */
843 while (offset >= register_size (gdbarch, regnum))
845 offset -= register_size (gdbarch, regnum);
852 int curr_len = register_size (gdbarch, regnum) - offset;
856 if (curr_len == register_size (gdbarch, regnum))
858 put_frame_register (frame, regnum, myaddr);
862 gdb_byte buf[MAX_REGISTER_SIZE];
863 frame_register_read (frame, regnum, buf);
864 memcpy (buf + offset, myaddr, curr_len);
865 put_frame_register (frame, regnum, buf);
875 /* Create a sentinel frame. */
877 static struct frame_info *
878 create_sentinel_frame (struct regcache *regcache)
880 struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
882 /* Explicitly initialize the sentinel frame's cache. Provide it
883 with the underlying regcache. In the future additional
884 information, such as the frame's thread will be added. */
885 frame->prologue_cache = sentinel_frame_cache (regcache);
886 /* For the moment there is only one sentinel frame implementation. */
887 frame->unwind = sentinel_frame_unwind;
888 /* Link this frame back to itself. The frame is self referential
889 (the unwound PC is the same as the pc), so make it so. */
891 /* Make the sentinel frame's ID valid, but invalid. That way all
892 comparisons with it should fail. */
893 frame->this_id.p = 1;
894 frame->this_id.value = null_frame_id;
897 fprintf_unfiltered (gdb_stdlog, "{ create_sentinel_frame (...) -> ");
898 fprint_frame (gdb_stdlog, frame);
899 fprintf_unfiltered (gdb_stdlog, " }\n");
904 /* Info about the innermost stack frame (contents of FP register) */
906 static struct frame_info *current_frame;
908 /* Cache for frame addresses already read by gdb. Valid only while
909 inferior is stopped. Control variables for the frame cache should
910 be local to this module. */
912 static struct obstack frame_cache_obstack;
915 frame_obstack_zalloc (unsigned long size)
917 void *data = obstack_alloc (&frame_cache_obstack, size);
918 memset (data, 0, size);
922 /* Return the innermost (currently executing) stack frame. This is
923 split into two functions. The function unwind_to_current_frame()
924 is wrapped in catch exceptions so that, even when the unwind of the
925 sentinel frame fails, the function still returns a stack frame. */
928 unwind_to_current_frame (struct ui_out *ui_out, void *args)
930 struct frame_info *frame = get_prev_frame (args);
931 /* A sentinel frame can fail to unwind, e.g., because its PC value
932 lands in somewhere like start. */
935 current_frame = frame;
940 get_current_frame (void)
942 /* First check, and report, the lack of registers. Having GDB
943 report "No stack!" or "No memory" when the target doesn't even
944 have registers is very confusing. Besides, "printcmd.exp"
945 explicitly checks that ``print $pc'' with no registers prints "No
947 if (!target_has_registers)
948 error (_("No registers."));
949 if (!target_has_stack)
950 error (_("No stack."));
951 if (!target_has_memory)
952 error (_("No memory."));
953 if (is_executing (inferior_ptid))
954 error (_("Target is executing."));
956 if (current_frame == NULL)
958 struct frame_info *sentinel_frame =
959 create_sentinel_frame (get_current_regcache ());
960 if (catch_exceptions (uiout, unwind_to_current_frame, sentinel_frame,
961 RETURN_MASK_ERROR) != 0)
963 /* Oops! Fake a current frame? Is this useful? It has a PC
964 of zero, for instance. */
965 current_frame = sentinel_frame;
968 return current_frame;
971 /* The "selected" stack frame is used by default for local and arg
972 access. May be zero, for no selected frame. */
974 static struct frame_info *selected_frame;
977 has_stack_frames (void)
979 if (!target_has_registers || !target_has_stack || !target_has_memory)
982 /* If the current thread is executing, don't try to read from
984 if (is_executing (inferior_ptid))
990 /* Return the selected frame. Always non-NULL (unless there isn't an
991 inferior sufficient for creating a frame) in which case an error is
995 get_selected_frame (const char *message)
997 if (selected_frame == NULL)
999 if (message != NULL && !has_stack_frames ())
1000 error (("%s"), message);
1001 /* Hey! Don't trust this. It should really be re-finding the
1002 last selected frame of the currently selected thread. This,
1003 though, is better than nothing. */
1004 select_frame (get_current_frame ());
1006 /* There is always a frame. */
1007 gdb_assert (selected_frame != NULL);
1008 return selected_frame;
1011 /* This is a variant of get_selected_frame() which can be called when
1012 the inferior does not have a frame; in that case it will return
1013 NULL instead of calling error(). */
1016 deprecated_safe_get_selected_frame (void)
1018 if (!has_stack_frames ())
1020 return get_selected_frame (NULL);
1023 /* Select frame FI (or NULL - to invalidate the current frame). */
1026 select_frame (struct frame_info *fi)
1030 selected_frame = fi;
1031 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
1032 frame is being invalidated. */
1033 if (deprecated_selected_frame_level_changed_hook)
1034 deprecated_selected_frame_level_changed_hook (frame_relative_level (fi));
1036 /* FIXME: kseitz/2002-08-28: It would be nice to call
1037 selected_frame_level_changed_event() right here, but due to limitations
1038 in the current interfaces, we would end up flooding UIs with events
1039 because select_frame() is used extensively internally.
1041 Once we have frame-parameterized frame (and frame-related) commands,
1042 the event notification can be moved here, since this function will only
1043 be called when the user's selected frame is being changed. */
1045 /* Ensure that symbols for this frame are read in. Also, determine the
1046 source language of this frame, and switch to it if desired. */
1049 /* We retrieve the frame's symtab by using the frame PC. However
1050 we cannot use the frame PC as-is, because it usually points to
1051 the instruction following the "call", which is sometimes the
1052 first instruction of another function. So we rely on
1053 get_frame_address_in_block() which provides us with a PC which
1054 is guaranteed to be inside the frame's code block. */
1055 s = find_pc_symtab (get_frame_address_in_block (fi));
1057 && s->language != current_language->la_language
1058 && s->language != language_unknown
1059 && language_mode == language_mode_auto)
1061 set_language (s->language);
1066 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
1067 Always returns a non-NULL value. */
1070 create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
1072 struct frame_info *fi;
1076 fprintf_unfiltered (gdb_stdlog,
1077 "{ create_new_frame (addr=0x%s, pc=0x%s) ",
1078 paddr_nz (addr), paddr_nz (pc));
1081 fi = FRAME_OBSTACK_ZALLOC (struct frame_info);
1083 fi->next = create_sentinel_frame (get_current_regcache ());
1085 /* Select/initialize both the unwind function and the frame's type
1087 fi->unwind = frame_unwind_find_by_frame (fi, &fi->prologue_cache);
1090 deprecated_update_frame_base_hack (fi, addr);
1091 deprecated_update_frame_pc_hack (fi, pc);
1095 fprintf_unfiltered (gdb_stdlog, "-> ");
1096 fprint_frame (gdb_stdlog, fi);
1097 fprintf_unfiltered (gdb_stdlog, " }\n");
1103 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
1104 innermost frame). Be careful to not fall off the bottom of the
1105 frame chain and onto the sentinel frame. */
1108 get_next_frame (struct frame_info *this_frame)
1110 if (this_frame->level > 0)
1111 return this_frame->next;
1116 /* Observer for the target_changed event. */
1119 frame_observer_target_changed (struct target_ops *target)
1121 reinit_frame_cache ();
1124 /* Flush the entire frame cache. */
1127 reinit_frame_cache (void)
1129 struct frame_info *fi;
1131 /* Tear down all frame caches. */
1132 for (fi = current_frame; fi != NULL; fi = fi->prev)
1134 if (fi->prologue_cache && fi->unwind->dealloc_cache)
1135 fi->unwind->dealloc_cache (fi, fi->prologue_cache);
1136 if (fi->base_cache && fi->base->unwind->dealloc_cache)
1137 fi->base->unwind->dealloc_cache (fi, fi->base_cache);
1140 /* Since we can't really be sure what the first object allocated was */
1141 obstack_free (&frame_cache_obstack, 0);
1142 obstack_init (&frame_cache_obstack);
1144 if (current_frame != NULL)
1145 annotate_frames_invalid ();
1147 current_frame = NULL; /* Invalidate cache */
1148 select_frame (NULL);
1150 fprintf_unfiltered (gdb_stdlog, "{ reinit_frame_cache () }\n");
1153 /* Find where a register is saved (in memory or another register).
1154 The result of frame_register_unwind is just where it is saved
1155 relative to this particular frame. */
1158 frame_register_unwind_location (struct frame_info *this_frame, int regnum,
1159 int *optimizedp, enum lval_type *lvalp,
1160 CORE_ADDR *addrp, int *realnump)
1162 gdb_assert (this_frame == NULL || this_frame->level >= 0);
1164 while (this_frame != NULL)
1166 frame_register_unwind (this_frame, regnum, optimizedp, lvalp,
1167 addrp, realnump, NULL);
1172 if (*lvalp != lval_register)
1176 this_frame = get_next_frame (this_frame);
1180 /* Return a "struct frame_info" corresponding to the frame that called
1181 THIS_FRAME. Returns NULL if there is no such frame.
1183 Unlike get_prev_frame, this function always tries to unwind the
1186 static struct frame_info *
1187 get_prev_frame_1 (struct frame_info *this_frame)
1189 struct frame_info *prev_frame;
1190 struct frame_id this_id;
1191 struct gdbarch *gdbarch;
1193 gdb_assert (this_frame != NULL);
1194 gdbarch = get_frame_arch (this_frame);
1198 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame_1 (this_frame=");
1199 if (this_frame != NULL)
1200 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
1202 fprintf_unfiltered (gdb_stdlog, "<NULL>");
1203 fprintf_unfiltered (gdb_stdlog, ") ");
1206 /* Only try to do the unwind once. */
1207 if (this_frame->prev_p)
1211 fprintf_unfiltered (gdb_stdlog, "-> ");
1212 fprint_frame (gdb_stdlog, this_frame->prev);
1213 fprintf_unfiltered (gdb_stdlog, " // cached \n");
1215 return this_frame->prev;
1218 /* If the frame unwinder hasn't been selected yet, we must do so
1219 before setting prev_p; otherwise the check for misbehaved
1220 sniffers will think that this frame's sniffer tried to unwind
1221 further (see frame_cleanup_after_sniffer). */
1222 if (this_frame->unwind == NULL)
1224 = frame_unwind_find_by_frame (this_frame, &this_frame->prologue_cache);
1226 this_frame->prev_p = 1;
1227 this_frame->stop_reason = UNWIND_NO_REASON;
1229 /* Check that this frame's ID was valid. If it wasn't, don't try to
1230 unwind to the prev frame. Be careful to not apply this test to
1231 the sentinel frame. */
1232 this_id = get_frame_id (this_frame);
1233 if (this_frame->level >= 0 && !frame_id_p (this_id))
1237 fprintf_unfiltered (gdb_stdlog, "-> ");
1238 fprint_frame (gdb_stdlog, NULL);
1239 fprintf_unfiltered (gdb_stdlog, " // this ID is NULL }\n");
1241 this_frame->stop_reason = UNWIND_NULL_ID;
1245 /* Check that this frame's ID isn't inner to (younger, below, next)
1246 the next frame. This happens when a frame unwind goes backwards.
1247 This check is valid only if the next frame is NORMAL. See the
1248 comment at frame_id_inner for details. */
1249 if (this_frame->next->unwind->type == NORMAL_FRAME
1250 && frame_id_inner (get_frame_arch (this_frame->next), this_id,
1251 get_frame_id (this_frame->next)))
1255 fprintf_unfiltered (gdb_stdlog, "-> ");
1256 fprint_frame (gdb_stdlog, NULL);
1257 fprintf_unfiltered (gdb_stdlog, " // this frame ID is inner }\n");
1259 this_frame->stop_reason = UNWIND_INNER_ID;
1263 /* Check that this and the next frame are not identical. If they
1264 are, there is most likely a stack cycle. As with the inner-than
1265 test above, avoid comparing the inner-most and sentinel frames. */
1266 if (this_frame->level > 0
1267 && frame_id_eq (this_id, get_frame_id (this_frame->next)))
1271 fprintf_unfiltered (gdb_stdlog, "-> ");
1272 fprint_frame (gdb_stdlog, NULL);
1273 fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n");
1275 this_frame->stop_reason = UNWIND_SAME_ID;
1279 /* Check that this and the next frame do not unwind the PC register
1280 to the same memory location. If they do, then even though they
1281 have different frame IDs, the new frame will be bogus; two
1282 functions can't share a register save slot for the PC. This can
1283 happen when the prologue analyzer finds a stack adjustment, but
1286 This check does assume that the "PC register" is roughly a
1287 traditional PC, even if the gdbarch_unwind_pc method adjusts
1288 it (we do not rely on the value, only on the unwound PC being
1289 dependent on this value). A potential improvement would be
1290 to have the frame prev_pc method and the gdbarch unwind_pc
1291 method set the same lval and location information as
1292 frame_register_unwind. */
1293 if (this_frame->level > 0
1294 && gdbarch_pc_regnum (gdbarch) >= 0
1295 && get_frame_type (this_frame) == NORMAL_FRAME
1296 && get_frame_type (this_frame->next) == NORMAL_FRAME)
1298 int optimized, realnum, nrealnum;
1299 enum lval_type lval, nlval;
1300 CORE_ADDR addr, naddr;
1302 frame_register_unwind_location (this_frame,
1303 gdbarch_pc_regnum (gdbarch),
1304 &optimized, &lval, &addr, &realnum);
1305 frame_register_unwind_location (get_next_frame (this_frame),
1306 gdbarch_pc_regnum (gdbarch),
1307 &optimized, &nlval, &naddr, &nrealnum);
1309 if ((lval == lval_memory && lval == nlval && addr == naddr)
1310 || (lval == lval_register && lval == nlval && realnum == nrealnum))
1314 fprintf_unfiltered (gdb_stdlog, "-> ");
1315 fprint_frame (gdb_stdlog, NULL);
1316 fprintf_unfiltered (gdb_stdlog, " // no saved PC }\n");
1319 this_frame->stop_reason = UNWIND_NO_SAVED_PC;
1320 this_frame->prev = NULL;
1325 /* Allocate the new frame but do not wire it in to the frame chain.
1326 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
1327 frame->next to pull some fancy tricks (of course such code is, by
1328 definition, recursive). Try to prevent it.
1330 There is no reason to worry about memory leaks, should the
1331 remainder of the function fail. The allocated memory will be
1332 quickly reclaimed when the frame cache is flushed, and the `we've
1333 been here before' check above will stop repeated memory
1334 allocation calls. */
1335 prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
1336 prev_frame->level = this_frame->level + 1;
1338 /* Don't yet compute ->unwind (and hence ->type). It is computed
1339 on-demand in get_frame_type, frame_register_unwind, and
1342 /* Don't yet compute the frame's ID. It is computed on-demand by
1345 /* The unwound frame ID is validate at the start of this function,
1346 as part of the logic to decide if that frame should be further
1347 unwound, and not here while the prev frame is being created.
1348 Doing this makes it possible for the user to examine a frame that
1349 has an invalid frame ID.
1351 Some very old VAX code noted: [...] For the sake of argument,
1352 suppose that the stack is somewhat trashed (which is one reason
1353 that "info frame" exists). So, return 0 (indicating we don't
1354 know the address of the arglist) if we don't know what frame this
1358 this_frame->prev = prev_frame;
1359 prev_frame->next = this_frame;
1363 fprintf_unfiltered (gdb_stdlog, "-> ");
1364 fprint_frame (gdb_stdlog, prev_frame);
1365 fprintf_unfiltered (gdb_stdlog, " }\n");
1371 /* Debug routine to print a NULL frame being returned. */
1374 frame_debug_got_null_frame (struct ui_file *file,
1375 struct frame_info *this_frame,
1380 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame (this_frame=");
1381 if (this_frame != NULL)
1382 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level);
1384 fprintf_unfiltered (gdb_stdlog, "<NULL>");
1385 fprintf_unfiltered (gdb_stdlog, ") -> // %s}\n", reason);
1389 /* Is this (non-sentinel) frame in the "main"() function? */
1392 inside_main_func (struct frame_info *this_frame)
1394 struct minimal_symbol *msymbol;
1397 if (symfile_objfile == 0)
1399 msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
1400 if (msymbol == NULL)
1402 /* Make certain that the code, and not descriptor, address is
1404 maddr = gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame),
1405 SYMBOL_VALUE_ADDRESS (msymbol),
1407 return maddr == get_frame_func (this_frame);
1410 /* Test whether THIS_FRAME is inside the process entry point function. */
1413 inside_entry_func (struct frame_info *this_frame)
1415 return (get_frame_func (this_frame) == entry_point_address ());
1418 /* Return a structure containing various interesting information about
1419 the frame that called THIS_FRAME. Returns NULL if there is entier
1420 no such frame or the frame fails any of a set of target-independent
1421 condition that should terminate the frame chain (e.g., as unwinding
1424 This function should not contain target-dependent tests, such as
1425 checking whether the program-counter is zero. */
1428 get_prev_frame (struct frame_info *this_frame)
1430 struct frame_info *prev_frame;
1432 /* Return the inner-most frame, when the caller passes in NULL. */
1433 /* NOTE: cagney/2002-11-09: Not sure how this would happen. The
1434 caller should have previously obtained a valid frame using
1435 get_selected_frame() and then called this code - only possibility
1436 I can think of is code behaving badly.
1438 NOTE: cagney/2003-01-10: Talk about code behaving badly. Check
1439 block_innermost_frame(). It does the sequence: frame = NULL;
1440 while (1) { frame = get_prev_frame (frame); .... }. Ulgh! Why
1441 it couldn't be written better, I don't know.
1443 NOTE: cagney/2003-01-11: I suspect what is happening in
1444 block_innermost_frame() is, when the target has no state
1445 (registers, memory, ...), it is still calling this function. The
1446 assumption being that this function will return NULL indicating
1447 that a frame isn't possible, rather than checking that the target
1448 has state and then calling get_current_frame() and
1449 get_prev_frame(). This is a guess mind. */
1450 if (this_frame == NULL)
1452 /* NOTE: cagney/2002-11-09: There was a code segment here that
1453 would error out when CURRENT_FRAME was NULL. The comment
1454 that went with it made the claim ...
1456 ``This screws value_of_variable, which just wants a nice
1457 clean NULL return from block_innermost_frame if there are no
1458 frames. I don't think I've ever seen this message happen
1459 otherwise. And returning NULL here is a perfectly legitimate
1462 Per the above, this code shouldn't even be called with a NULL
1464 frame_debug_got_null_frame (gdb_stdlog, this_frame, "this_frame NULL");
1465 return current_frame;
1468 /* There is always a frame. If this assertion fails, suspect that
1469 something should be calling get_selected_frame() or
1470 get_current_frame(). */
1471 gdb_assert (this_frame != NULL);
1473 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
1474 sense to stop unwinding at a dummy frame. One place where a dummy
1475 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
1476 pcsqh register (space register for the instruction at the head of the
1477 instruction queue) cannot be written directly; the only way to set it
1478 is to branch to code that is in the target space. In order to implement
1479 frame dummies on HPUX, the called function is made to jump back to where
1480 the inferior was when the user function was called. If gdb was inside
1481 the main function when we created the dummy frame, the dummy frame will
1482 point inside the main function. */
1483 if (this_frame->level >= 0
1484 && get_frame_type (this_frame) != DUMMY_FRAME
1485 && !backtrace_past_main
1486 && inside_main_func (this_frame))
1487 /* Don't unwind past main(). Note, this is done _before_ the
1488 frame has been marked as previously unwound. That way if the
1489 user later decides to enable unwinds past main(), that will
1490 automatically happen. */
1492 frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside main func");
1496 /* If the user's backtrace limit has been exceeded, stop. We must
1497 add two to the current level; one of those accounts for backtrace_limit
1498 being 1-based and the level being 0-based, and the other accounts for
1499 the level of the new frame instead of the level of the current
1501 if (this_frame->level + 2 > backtrace_limit)
1503 frame_debug_got_null_frame (gdb_stdlog, this_frame,
1504 "backtrace limit exceeded");
1508 /* If we're already inside the entry function for the main objfile,
1509 then it isn't valid. Don't apply this test to a dummy frame -
1510 dummy frame PCs typically land in the entry func. Don't apply
1511 this test to the sentinel frame. Sentinel frames should always
1512 be allowed to unwind. */
1513 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
1514 wasn't checking for "main" in the minimal symbols. With that
1515 fixed asm-source tests now stop in "main" instead of halting the
1516 backtrace in weird and wonderful ways somewhere inside the entry
1517 file. Suspect that tests for inside the entry file/func were
1518 added to work around that (now fixed) case. */
1519 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
1520 suggested having the inside_entry_func test use the
1521 inside_main_func() msymbol trick (along with entry_point_address()
1522 I guess) to determine the address range of the start function.
1523 That should provide a far better stopper than the current
1525 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
1526 applied tail-call optimizations to main so that a function called
1527 from main returns directly to the caller of main. Since we don't
1528 stop at main, we should at least stop at the entry point of the
1530 if (!backtrace_past_entry
1531 && get_frame_type (this_frame) != DUMMY_FRAME && this_frame->level >= 0
1532 && inside_entry_func (this_frame))
1534 frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside entry func");
1538 /* Assume that the only way to get a zero PC is through something
1539 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
1540 will never unwind a zero PC. */
1541 if (this_frame->level > 0
1542 && get_frame_type (this_frame) == NORMAL_FRAME
1543 && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME
1544 && get_frame_pc (this_frame) == 0)
1546 frame_debug_got_null_frame (gdb_stdlog, this_frame, "zero PC");
1550 return get_prev_frame_1 (this_frame);
1554 get_frame_pc (struct frame_info *frame)
1556 gdb_assert (frame->next != NULL);
1557 return frame_pc_unwind (frame->next);
1560 /* Return an address that falls within THIS_FRAME's code block. */
1563 get_frame_address_in_block (struct frame_info *this_frame)
1565 /* A draft address. */
1566 CORE_ADDR pc = get_frame_pc (this_frame);
1568 struct frame_info *next_frame = this_frame->next;
1570 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
1571 Normally the resume address is inside the body of the function
1572 associated with THIS_FRAME, but there is a special case: when
1573 calling a function which the compiler knows will never return
1574 (for instance abort), the call may be the very last instruction
1575 in the calling function. The resume address will point after the
1576 call and may be at the beginning of a different function
1579 If THIS_FRAME is a signal frame or dummy frame, then we should
1580 not adjust the unwound PC. For a dummy frame, GDB pushed the
1581 resume address manually onto the stack. For a signal frame, the
1582 OS may have pushed the resume address manually and invoked the
1583 handler (e.g. GNU/Linux), or invoked the trampoline which called
1584 the signal handler - but in either case the signal handler is
1585 expected to return to the trampoline. So in both of these
1586 cases we know that the resume address is executable and
1587 related. So we only need to adjust the PC if THIS_FRAME
1588 is a normal function.
1590 If the program has been interrupted while THIS_FRAME is current,
1591 then clearly the resume address is inside the associated
1592 function. There are three kinds of interruption: debugger stop
1593 (next frame will be SENTINEL_FRAME), operating system
1594 signal or exception (next frame will be SIGTRAMP_FRAME),
1595 or debugger-induced function call (next frame will be
1596 DUMMY_FRAME). So we only need to adjust the PC if
1597 NEXT_FRAME is a normal function.
1599 We check the type of NEXT_FRAME first, since it is already
1600 known; frame type is determined by the unwinder, and since
1601 we have THIS_FRAME we've already selected an unwinder for
1603 if (get_frame_type (next_frame) == NORMAL_FRAME
1604 && get_frame_type (this_frame) == NORMAL_FRAME)
1611 pc_notcurrent (struct frame_info *frame)
1613 /* If FRAME is not the innermost frame, that normally means that
1614 FRAME->pc points at the return instruction (which is *after* the
1615 call instruction), and we want to get the line containing the
1616 call (because the call is where the user thinks the program is).
1617 However, if the next frame is either a SIGTRAMP_FRAME or a
1618 DUMMY_FRAME, then the next frame will contain a saved interrupt
1619 PC and such a PC indicates the current (rather than next)
1620 instruction/line, consequently, for such cases, want to get the
1621 line containing fi->pc. */
1622 struct frame_info *next = get_next_frame (frame);
1623 int notcurrent = (next != NULL && get_frame_type (next) == NORMAL_FRAME);
1628 find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal)
1630 (*sal) = find_pc_line (get_frame_pc (frame), pc_notcurrent (frame));
1633 /* Per "frame.h", return the ``address'' of the frame. Code should
1634 really be using get_frame_id(). */
1636 get_frame_base (struct frame_info *fi)
1638 return get_frame_id (fi).stack_addr;
1641 /* High-level offsets into the frame. Used by the debug info. */
1644 get_frame_base_address (struct frame_info *fi)
1646 if (get_frame_type (fi) != NORMAL_FRAME)
1648 if (fi->base == NULL)
1649 fi->base = frame_base_find_by_frame (fi);
1650 /* Sneaky: If the low-level unwind and high-level base code share a
1651 common unwinder, let them share the prologue cache. */
1652 if (fi->base->unwind == fi->unwind)
1653 return fi->base->this_base (fi, &fi->prologue_cache);
1654 return fi->base->this_base (fi, &fi->base_cache);
1658 get_frame_locals_address (struct frame_info *fi)
1661 if (get_frame_type (fi) != NORMAL_FRAME)
1663 /* If there isn't a frame address method, find it. */
1664 if (fi->base == NULL)
1665 fi->base = frame_base_find_by_frame (fi);
1666 /* Sneaky: If the low-level unwind and high-level base code share a
1667 common unwinder, let them share the prologue cache. */
1668 if (fi->base->unwind == fi->unwind)
1669 return fi->base->this_locals (fi, &fi->prologue_cache);
1670 return fi->base->this_locals (fi, &fi->base_cache);
1674 get_frame_args_address (struct frame_info *fi)
1677 if (get_frame_type (fi) != NORMAL_FRAME)
1679 /* If there isn't a frame address method, find it. */
1680 if (fi->base == NULL)
1681 fi->base = frame_base_find_by_frame (fi);
1682 /* Sneaky: If the low-level unwind and high-level base code share a
1683 common unwinder, let them share the prologue cache. */
1684 if (fi->base->unwind == fi->unwind)
1685 return fi->base->this_args (fi, &fi->prologue_cache);
1686 return fi->base->this_args (fi, &fi->base_cache);
1689 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
1690 or -1 for a NULL frame. */
1693 frame_relative_level (struct frame_info *fi)
1702 get_frame_type (struct frame_info *frame)
1704 if (frame->unwind == NULL)
1705 /* Initialize the frame's unwinder because that's what
1706 provides the frame's type. */
1707 frame->unwind = frame_unwind_find_by_frame (frame, &frame->prologue_cache);
1708 return frame->unwind->type;
1712 deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc)
1715 fprintf_unfiltered (gdb_stdlog,
1716 "{ deprecated_update_frame_pc_hack (frame=%d,pc=0x%s) }\n",
1717 frame->level, paddr_nz (pc));
1718 /* NOTE: cagney/2003-03-11: Some architectures (e.g., Arm) are
1719 maintaining a locally allocated frame object. Since such frames
1720 are not in the frame chain, it isn't possible to assume that the
1721 frame has a next. Sigh. */
1722 if (frame->next != NULL)
1724 /* While we're at it, update this frame's cached PC value, found
1725 in the next frame. Oh for the day when "struct frame_info"
1726 is opaque and this hack on hack can just go away. */
1727 frame->next->prev_pc.value = pc;
1728 frame->next->prev_pc.p = 1;
1733 deprecated_update_frame_base_hack (struct frame_info *frame, CORE_ADDR base)
1736 fprintf_unfiltered (gdb_stdlog,
1737 "{ deprecated_update_frame_base_hack (frame=%d,base=0x%s) }\n",
1738 frame->level, paddr_nz (base));
1739 /* See comment in "frame.h". */
1740 frame->this_id.value.stack_addr = base;
1743 /* Memory access methods. */
1746 get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr,
1747 gdb_byte *buf, int len)
1749 read_memory (addr, buf, len);
1753 get_frame_memory_signed (struct frame_info *this_frame, CORE_ADDR addr,
1756 return read_memory_integer (addr, len);
1760 get_frame_memory_unsigned (struct frame_info *this_frame, CORE_ADDR addr,
1763 return read_memory_unsigned_integer (addr, len);
1767 safe_frame_unwind_memory (struct frame_info *this_frame,
1768 CORE_ADDR addr, gdb_byte *buf, int len)
1770 /* NOTE: target_read_memory returns zero on success! */
1771 return !target_read_memory (addr, buf, len);
1774 /* Architecture method. */
1777 get_frame_arch (struct frame_info *this_frame)
1779 return current_gdbarch;
1782 /* Stack pointer methods. */
1785 get_frame_sp (struct frame_info *this_frame)
1787 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1788 /* Normality - an architecture that provides a way of obtaining any
1789 frame inner-most address. */
1790 if (gdbarch_unwind_sp_p (gdbarch))
1791 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
1792 operate on THIS_FRAME now. */
1793 return gdbarch_unwind_sp (gdbarch, this_frame->next);
1794 /* Now things are really are grim. Hope that the value returned by
1795 the gdbarch_sp_regnum register is meaningful. */
1796 if (gdbarch_sp_regnum (gdbarch) >= 0)
1797 return get_frame_register_unsigned (this_frame,
1798 gdbarch_sp_regnum (gdbarch));
1799 internal_error (__FILE__, __LINE__, _("Missing unwind SP method"));
1802 /* Return the reason why we can't unwind past FRAME. */
1804 enum unwind_stop_reason
1805 get_frame_unwind_stop_reason (struct frame_info *frame)
1807 /* If we haven't tried to unwind past this point yet, then assume
1808 that unwinding would succeed. */
1809 if (frame->prev_p == 0)
1810 return UNWIND_NO_REASON;
1812 /* Otherwise, we set a reason when we succeeded (or failed) to
1814 return frame->stop_reason;
1817 /* Return a string explaining REASON. */
1820 frame_stop_reason_string (enum unwind_stop_reason reason)
1824 case UNWIND_NULL_ID:
1825 return _("unwinder did not report frame ID");
1827 case UNWIND_INNER_ID:
1828 return _("previous frame inner to this frame (corrupt stack?)");
1830 case UNWIND_SAME_ID:
1831 return _("previous frame identical to this frame (corrupt stack?)");
1833 case UNWIND_NO_SAVED_PC:
1834 return _("frame did not save the PC");
1836 case UNWIND_NO_REASON:
1837 case UNWIND_FIRST_ERROR:
1839 internal_error (__FILE__, __LINE__,
1840 "Invalid frame stop reason");
1844 /* Clean up after a failed (wrong unwinder) attempt to unwind past
1848 frame_cleanup_after_sniffer (void *arg)
1850 struct frame_info *frame = arg;
1852 /* The sniffer should not allocate a prologue cache if it did not
1853 match this frame. */
1854 gdb_assert (frame->prologue_cache == NULL);
1856 /* No sniffer should extend the frame chain; sniff based on what is
1858 gdb_assert (!frame->prev_p);
1860 /* The sniffer should not check the frame's ID; that's circular. */
1861 gdb_assert (!frame->this_id.p);
1863 /* Clear cached fields dependent on the unwinder.
1865 The previous PC is independent of the unwinder, but the previous
1866 function is not (see get_frame_address_in_block). */
1867 frame->prev_func.p = 0;
1868 frame->prev_func.addr = 0;
1870 /* Discard the unwinder last, so that we can easily find it if an assertion
1871 in this function triggers. */
1872 frame->unwind = NULL;
1875 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
1876 Return a cleanup which should be called if unwinding fails, and
1877 discarded if it succeeds. */
1880 frame_prepare_for_sniffer (struct frame_info *frame,
1881 const struct frame_unwind *unwind)
1883 gdb_assert (frame->unwind == NULL);
1884 frame->unwind = unwind;
1885 return make_cleanup (frame_cleanup_after_sniffer, frame);
1888 extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */
1890 static struct cmd_list_element *set_backtrace_cmdlist;
1891 static struct cmd_list_element *show_backtrace_cmdlist;
1894 set_backtrace_cmd (char *args, int from_tty)
1896 help_list (set_backtrace_cmdlist, "set backtrace ", -1, gdb_stdout);
1900 show_backtrace_cmd (char *args, int from_tty)
1902 cmd_show_list (show_backtrace_cmdlist, from_tty, "");
1906 _initialize_frame (void)
1908 obstack_init (&frame_cache_obstack);
1910 observer_attach_target_changed (frame_observer_target_changed);
1912 add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, _("\
1913 Set backtrace specific variables.\n\
1914 Configure backtrace variables such as the backtrace limit"),
1915 &set_backtrace_cmdlist, "set backtrace ",
1916 0/*allow-unknown*/, &setlist);
1917 add_prefix_cmd ("backtrace", class_maintenance, show_backtrace_cmd, _("\
1918 Show backtrace specific variables\n\
1919 Show backtrace variables such as the backtrace limit"),
1920 &show_backtrace_cmdlist, "show backtrace ",
1921 0/*allow-unknown*/, &showlist);
1923 add_setshow_boolean_cmd ("past-main", class_obscure,
1924 &backtrace_past_main, _("\
1925 Set whether backtraces should continue past \"main\"."), _("\
1926 Show whether backtraces should continue past \"main\"."), _("\
1927 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
1928 the backtrace at \"main\". Set this variable if you need to see the rest\n\
1929 of the stack trace."),
1931 show_backtrace_past_main,
1932 &set_backtrace_cmdlist,
1933 &show_backtrace_cmdlist);
1935 add_setshow_boolean_cmd ("past-entry", class_obscure,
1936 &backtrace_past_entry, _("\
1937 Set whether backtraces should continue past the entry point of a program."),
1939 Show whether backtraces should continue past the entry point of a program."),
1941 Normally there are no callers beyond the entry point of a program, so GDB\n\
1942 will terminate the backtrace there. Set this variable if you need to see \n\
1943 the rest of the stack trace."),
1945 show_backtrace_past_entry,
1946 &set_backtrace_cmdlist,
1947 &show_backtrace_cmdlist);
1949 add_setshow_integer_cmd ("limit", class_obscure,
1950 &backtrace_limit, _("\
1951 Set an upper bound on the number of backtrace levels."), _("\
1952 Show the upper bound on the number of backtrace levels."), _("\
1953 No more than the specified number of frames can be displayed or examined.\n\
1954 Zero is unlimited."),
1956 show_backtrace_limit,
1957 &set_backtrace_cmdlist,
1958 &show_backtrace_cmdlist);
1960 /* Debug this files internals. */
1961 add_setshow_zinteger_cmd ("frame", class_maintenance, &frame_debug, _("\
1962 Set frame debugging."), _("\
1963 Show frame debugging."), _("\
1964 When non-zero, frame specific internal debugging is enabled."),
1967 &setdebuglist, &showdebuglist);