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
);
372 frame_id_inner (struct gdbarch
*gdbarch
, struct frame_id l
, struct frame_id r
)
375 if (!l
.stack_addr_p
|| !r
.stack_addr_p
)
376 /* Like NaN, any operation involving an invalid ID always fails. */
379 /* Only return non-zero when strictly inner than. Note that, per
380 comment in "frame.h", there is some fuzz here. Frameless
381 functions are not strictly inner than (same .stack but
382 different .code and/or .special address). */
383 inner
= gdbarch_inner_than (gdbarch
, l
.stack_addr
, r
.stack_addr
);
386 fprintf_unfiltered (gdb_stdlog
, "{ frame_id_inner (l=");
387 fprint_frame_id (gdb_stdlog
, l
);
388 fprintf_unfiltered (gdb_stdlog
, ",r=");
389 fprint_frame_id (gdb_stdlog
, r
);
390 fprintf_unfiltered (gdb_stdlog
, ") -> %d }\n", inner
);
396 frame_find_by_id (struct frame_id id
)
398 struct frame_info
*frame
;
400 /* ZERO denotes the null frame, let the caller decide what to do
401 about it. Should it instead return get_current_frame()? */
402 if (!frame_id_p (id
))
405 for (frame
= get_current_frame ();
407 frame
= get_prev_frame (frame
))
409 struct frame_id
this = get_frame_id (frame
);
410 if (frame_id_eq (id
, this))
411 /* An exact match. */
413 if (frame_id_inner (get_frame_arch (frame
), id
, this))
416 /* Either we're not yet gone far enough out along the frame
417 chain (inner(this,id)), or we're comparing frameless functions
418 (same .base, different .func, no test available). Struggle
419 on until we've definitly gone to far. */
425 frame_pc_unwind (struct frame_info
*this_frame
)
427 if (!this_frame
->prev_pc
.p
)
430 if (gdbarch_unwind_pc_p (get_frame_arch (this_frame
)))
432 /* The right way. The `pure' way. The one true way. This
433 method depends solely on the register-unwind code to
434 determine the value of registers in THIS frame, and hence
435 the value of this frame's PC (resume address). A typical
436 implementation is no more than:
438 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf);
439 return extract_unsigned_integer (buf, size of ISA_PC_REGNUM);
441 Note: this method is very heavily dependent on a correct
442 register-unwind implementation, it pays to fix that
443 method first; this method is frame type agnostic, since
444 it only deals with register values, it works with any
445 frame. This is all in stark contrast to the old
446 FRAME_SAVED_PC which would try to directly handle all the
447 different ways that a PC could be unwound. */
448 pc
= gdbarch_unwind_pc (get_frame_arch (this_frame
), this_frame
);
451 internal_error (__FILE__
, __LINE__
, _("No unwind_pc method"));
452 this_frame
->prev_pc
.value
= pc
;
453 this_frame
->prev_pc
.p
= 1;
455 fprintf_unfiltered (gdb_stdlog
,
456 "{ frame_pc_unwind (this_frame=%d) -> 0x%s }\n",
458 paddr_nz (this_frame
->prev_pc
.value
));
460 return this_frame
->prev_pc
.value
;
464 get_frame_func (struct frame_info
*this_frame
)
466 struct frame_info
*next_frame
= this_frame
->next
;
468 if (!next_frame
->prev_func
.p
)
470 /* Make certain that this, and not the adjacent, function is
472 CORE_ADDR addr_in_block
= get_frame_address_in_block (this_frame
);
473 next_frame
->prev_func
.p
= 1;
474 next_frame
->prev_func
.addr
= get_pc_function_start (addr_in_block
);
476 fprintf_unfiltered (gdb_stdlog
,
477 "{ get_frame_func (this_frame=%d) -> 0x%s }\n",
479 paddr_nz (next_frame
->prev_func
.addr
));
481 return next_frame
->prev_func
.addr
;
485 do_frame_register_read (void *src
, int regnum
, gdb_byte
*buf
)
487 return frame_register_read (src
, regnum
, buf
);
491 frame_save_as_regcache (struct frame_info
*this_frame
)
493 struct regcache
*regcache
= regcache_xmalloc (get_frame_arch (this_frame
));
494 struct cleanup
*cleanups
= make_cleanup_regcache_xfree (regcache
);
495 regcache_save (regcache
, do_frame_register_read
, this_frame
);
496 discard_cleanups (cleanups
);
501 frame_pop (struct frame_info
*this_frame
)
503 struct frame_info
*prev_frame
;
504 struct regcache
*scratch
;
505 struct cleanup
*cleanups
;
507 /* Ensure that we have a frame to pop to. */
508 prev_frame
= get_prev_frame_1 (this_frame
);
511 error (_("Cannot pop the initial frame."));
513 /* Make a copy of all the register values unwound from this frame.
514 Save them in a scratch buffer so that there isn't a race between
515 trying to extract the old values from the current regcache while
516 at the same time writing new values into that same cache. */
517 scratch
= frame_save_as_regcache (prev_frame
);
518 cleanups
= make_cleanup_regcache_xfree (scratch
);
520 /* FIXME: cagney/2003-03-16: It should be possible to tell the
521 target's register cache that it is about to be hit with a burst
522 register transfer and that the sequence of register writes should
523 be batched. The pair target_prepare_to_store() and
524 target_store_registers() kind of suggest this functionality.
525 Unfortunately, they don't implement it. Their lack of a formal
526 definition can lead to targets writing back bogus values
527 (arguably a bug in the target code mind). */
528 /* Now copy those saved registers into the current regcache.
529 Here, regcache_cpy() calls regcache_restore(). */
530 regcache_cpy (get_current_regcache (), scratch
);
531 do_cleanups (cleanups
);
533 /* We've made right mess of GDB's local state, just discard
535 reinit_frame_cache ();
539 frame_register_unwind (struct frame_info
*frame
, int regnum
,
540 int *optimizedp
, enum lval_type
*lvalp
,
541 CORE_ADDR
*addrp
, int *realnump
, gdb_byte
*bufferp
)
545 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
546 that the value proper does not need to be fetched. */
547 gdb_assert (optimizedp
!= NULL
);
548 gdb_assert (lvalp
!= NULL
);
549 gdb_assert (addrp
!= NULL
);
550 gdb_assert (realnump
!= NULL
);
551 /* gdb_assert (bufferp != NULL); */
553 value
= frame_unwind_register_value (frame
, regnum
);
555 gdb_assert (value
!= NULL
);
557 *optimizedp
= value_optimized_out (value
);
558 *lvalp
= VALUE_LVAL (value
);
559 *addrp
= VALUE_ADDRESS (value
);
560 *realnump
= VALUE_REGNUM (value
);
563 memcpy (bufferp
, value_contents_all (value
),
564 TYPE_LENGTH (value_type (value
)));
566 /* Dispose of the new value. This prevents watchpoints from
567 trying to watch the saved frame pointer. */
568 release_value (value
);
573 frame_register (struct frame_info
*frame
, int regnum
,
574 int *optimizedp
, enum lval_type
*lvalp
,
575 CORE_ADDR
*addrp
, int *realnump
, gdb_byte
*bufferp
)
577 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
578 that the value proper does not need to be fetched. */
579 gdb_assert (optimizedp
!= NULL
);
580 gdb_assert (lvalp
!= NULL
);
581 gdb_assert (addrp
!= NULL
);
582 gdb_assert (realnump
!= NULL
);
583 /* gdb_assert (bufferp != NULL); */
585 /* Obtain the register value by unwinding the register from the next
586 (more inner frame). */
587 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
588 frame_register_unwind (frame
->next
, regnum
, optimizedp
, lvalp
, addrp
,
593 frame_unwind_register (struct frame_info
*frame
, int regnum
, gdb_byte
*buf
)
599 frame_register_unwind (frame
, regnum
, &optimized
, &lval
, &addr
,
604 get_frame_register (struct frame_info
*frame
,
605 int regnum
, gdb_byte
*buf
)
607 frame_unwind_register (frame
->next
, regnum
, buf
);
611 frame_unwind_register_value (struct frame_info
*frame
, int regnum
)
615 gdb_assert (frame
!= NULL
);
619 fprintf_unfiltered (gdb_stdlog
, "\
620 { frame_unwind_register_value (frame=%d,regnum=%d(%s),...) ",
621 frame
->level
, regnum
,
622 user_reg_map_regnum_to_name
623 (get_frame_arch (frame
), regnum
));
626 /* Find the unwinder. */
627 if (frame
->unwind
== NULL
)
628 frame
->unwind
= frame_unwind_find_by_frame (frame
, &frame
->prologue_cache
);
630 /* Ask this frame to unwind its register. */
631 value
= frame
->unwind
->prev_register (frame
, &frame
->prologue_cache
, regnum
);
635 fprintf_unfiltered (gdb_stdlog
, "->");
636 if (value_optimized_out (value
))
637 fprintf_unfiltered (gdb_stdlog
, " optimized out");
640 if (VALUE_LVAL (value
) == lval_register
)
641 fprintf_unfiltered (gdb_stdlog
, " register=%d",
642 VALUE_REGNUM (value
));
643 else if (VALUE_LVAL (value
) == lval_memory
)
644 fprintf_unfiltered (gdb_stdlog
, " address=0x%s",
645 paddr_nz (VALUE_ADDRESS (value
)));
647 fprintf_unfiltered (gdb_stdlog
, " computed");
649 if (value_lazy (value
))
650 fprintf_unfiltered (gdb_stdlog
, " lazy");
654 const gdb_byte
*buf
= value_contents (value
);
656 fprintf_unfiltered (gdb_stdlog
, " bytes=");
657 fprintf_unfiltered (gdb_stdlog
, "[");
658 for (i
= 0; i
< register_size (get_frame_arch (frame
), regnum
); i
++)
659 fprintf_unfiltered (gdb_stdlog
, "%02x", buf
[i
]);
660 fprintf_unfiltered (gdb_stdlog
, "]");
664 fprintf_unfiltered (gdb_stdlog
, " }\n");
671 get_frame_register_value (struct frame_info
*frame
, int regnum
)
673 return frame_unwind_register_value (frame
->next
, regnum
);
677 frame_unwind_register_signed (struct frame_info
*frame
, int regnum
)
679 gdb_byte buf
[MAX_REGISTER_SIZE
];
680 frame_unwind_register (frame
, regnum
, buf
);
681 return extract_signed_integer (buf
, register_size (get_frame_arch (frame
),
686 get_frame_register_signed (struct frame_info
*frame
, int regnum
)
688 return frame_unwind_register_signed (frame
->next
, regnum
);
692 frame_unwind_register_unsigned (struct frame_info
*frame
, int regnum
)
694 gdb_byte buf
[MAX_REGISTER_SIZE
];
695 frame_unwind_register (frame
, regnum
, buf
);
696 return extract_unsigned_integer (buf
, register_size (get_frame_arch (frame
),
701 get_frame_register_unsigned (struct frame_info
*frame
, int regnum
)
703 return frame_unwind_register_unsigned (frame
->next
, regnum
);
707 put_frame_register (struct frame_info
*frame
, int regnum
,
710 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
715 frame_register (frame
, regnum
, &optim
, &lval
, &addr
, &realnum
, NULL
);
717 error (_("Attempt to assign to a value that was optimized out."));
722 /* FIXME: write_memory doesn't yet take constant buffers.
724 gdb_byte tmp
[MAX_REGISTER_SIZE
];
725 memcpy (tmp
, buf
, register_size (gdbarch
, regnum
));
726 write_memory (addr
, tmp
, register_size (gdbarch
, regnum
));
730 regcache_cooked_write (get_current_regcache (), realnum
, buf
);
733 error (_("Attempt to assign to an unmodifiable value."));
737 /* frame_register_read ()
739 Find and return the value of REGNUM for the specified stack frame.
740 The number of bytes copied is REGISTER_SIZE (REGNUM).
742 Returns 0 if the register value could not be found. */
745 frame_register_read (struct frame_info
*frame
, int regnum
,
752 frame_register (frame
, regnum
, &optimized
, &lval
, &addr
, &realnum
, myaddr
);
758 get_frame_register_bytes (struct frame_info
*frame
, int regnum
,
759 CORE_ADDR offset
, int len
, gdb_byte
*myaddr
)
761 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
763 /* Skip registers wholly inside of OFFSET. */
764 while (offset
>= register_size (gdbarch
, regnum
))
766 offset
-= register_size (gdbarch
, regnum
);
773 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
777 if (curr_len
== register_size (gdbarch
, regnum
))
779 if (!frame_register_read (frame
, regnum
, myaddr
))
784 gdb_byte buf
[MAX_REGISTER_SIZE
];
785 if (!frame_register_read (frame
, regnum
, buf
))
787 memcpy (myaddr
, buf
+ offset
, curr_len
);
800 put_frame_register_bytes (struct frame_info
*frame
, int regnum
,
801 CORE_ADDR offset
, int len
, const gdb_byte
*myaddr
)
803 struct gdbarch
*gdbarch
= get_frame_arch (frame
);
805 /* Skip registers wholly inside of OFFSET. */
806 while (offset
>= register_size (gdbarch
, regnum
))
808 offset
-= register_size (gdbarch
, regnum
);
815 int curr_len
= register_size (gdbarch
, regnum
) - offset
;
819 if (curr_len
== register_size (gdbarch
, regnum
))
821 put_frame_register (frame
, regnum
, myaddr
);
825 gdb_byte buf
[MAX_REGISTER_SIZE
];
826 frame_register_read (frame
, regnum
, buf
);
827 memcpy (buf
+ offset
, myaddr
, curr_len
);
828 put_frame_register (frame
, regnum
, buf
);
838 /* Create a sentinel frame. */
840 static struct frame_info
*
841 create_sentinel_frame (struct regcache
*regcache
)
843 struct frame_info
*frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
845 /* Explicitly initialize the sentinel frame's cache. Provide it
846 with the underlying regcache. In the future additional
847 information, such as the frame's thread will be added. */
848 frame
->prologue_cache
= sentinel_frame_cache (regcache
);
849 /* For the moment there is only one sentinel frame implementation. */
850 frame
->unwind
= sentinel_frame_unwind
;
851 /* Link this frame back to itself. The frame is self referential
852 (the unwound PC is the same as the pc), so make it so. */
854 /* Make the sentinel frame's ID valid, but invalid. That way all
855 comparisons with it should fail. */
856 frame
->this_id
.p
= 1;
857 frame
->this_id
.value
= null_frame_id
;
860 fprintf_unfiltered (gdb_stdlog
, "{ create_sentinel_frame (...) -> ");
861 fprint_frame (gdb_stdlog
, frame
);
862 fprintf_unfiltered (gdb_stdlog
, " }\n");
867 /* Info about the innermost stack frame (contents of FP register) */
869 static struct frame_info
*current_frame
;
871 /* Cache for frame addresses already read by gdb. Valid only while
872 inferior is stopped. Control variables for the frame cache should
873 be local to this module. */
875 static struct obstack frame_cache_obstack
;
878 frame_obstack_zalloc (unsigned long size
)
880 void *data
= obstack_alloc (&frame_cache_obstack
, size
);
881 memset (data
, 0, size
);
885 /* Return the innermost (currently executing) stack frame. This is
886 split into two functions. The function unwind_to_current_frame()
887 is wrapped in catch exceptions so that, even when the unwind of the
888 sentinel frame fails, the function still returns a stack frame. */
891 unwind_to_current_frame (struct ui_out
*ui_out
, void *args
)
893 struct frame_info
*frame
= get_prev_frame (args
);
894 /* A sentinel frame can fail to unwind, e.g., because its PC value
895 lands in somewhere like start. */
898 current_frame
= frame
;
903 get_current_frame (void)
905 /* First check, and report, the lack of registers. Having GDB
906 report "No stack!" or "No memory" when the target doesn't even
907 have registers is very confusing. Besides, "printcmd.exp"
908 explicitly checks that ``print $pc'' with no registers prints "No
910 if (!target_has_registers
)
911 error (_("No registers."));
912 if (!target_has_stack
)
913 error (_("No stack."));
914 if (!target_has_memory
)
915 error (_("No memory."));
916 if (is_executing (inferior_ptid
))
917 error (_("Target is executing."));
919 if (current_frame
== NULL
)
921 struct frame_info
*sentinel_frame
=
922 create_sentinel_frame (get_current_regcache ());
923 if (catch_exceptions (uiout
, unwind_to_current_frame
, sentinel_frame
,
924 RETURN_MASK_ERROR
) != 0)
926 /* Oops! Fake a current frame? Is this useful? It has a PC
927 of zero, for instance. */
928 current_frame
= sentinel_frame
;
931 return current_frame
;
934 /* The "selected" stack frame is used by default for local and arg
935 access. May be zero, for no selected frame. */
937 static struct frame_info
*selected_frame
;
940 has_stack_frames (void)
942 if (!target_has_registers
|| !target_has_stack
|| !target_has_memory
)
945 /* If the current thread is executing, don't try to read from
947 if (is_executing (inferior_ptid
))
953 /* Return the selected frame. Always non-NULL (unless there isn't an
954 inferior sufficient for creating a frame) in which case an error is
958 get_selected_frame (const char *message
)
960 if (selected_frame
== NULL
)
962 if (message
!= NULL
&& !has_stack_frames ())
963 error (("%s"), message
);
964 /* Hey! Don't trust this. It should really be re-finding the
965 last selected frame of the currently selected thread. This,
966 though, is better than nothing. */
967 select_frame (get_current_frame ());
969 /* There is always a frame. */
970 gdb_assert (selected_frame
!= NULL
);
971 return selected_frame
;
974 /* This is a variant of get_selected_frame() which can be called when
975 the inferior does not have a frame; in that case it will return
976 NULL instead of calling error(). */
979 deprecated_safe_get_selected_frame (void)
981 if (!has_stack_frames ())
983 return get_selected_frame (NULL
);
986 /* Select frame FI (or NULL - to invalidate the current frame). */
989 select_frame (struct frame_info
*fi
)
994 /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the
995 frame is being invalidated. */
996 if (deprecated_selected_frame_level_changed_hook
)
997 deprecated_selected_frame_level_changed_hook (frame_relative_level (fi
));
999 /* FIXME: kseitz/2002-08-28: It would be nice to call
1000 selected_frame_level_changed_event() right here, but due to limitations
1001 in the current interfaces, we would end up flooding UIs with events
1002 because select_frame() is used extensively internally.
1004 Once we have frame-parameterized frame (and frame-related) commands,
1005 the event notification can be moved here, since this function will only
1006 be called when the user's selected frame is being changed. */
1008 /* Ensure that symbols for this frame are read in. Also, determine the
1009 source language of this frame, and switch to it if desired. */
1012 /* We retrieve the frame's symtab by using the frame PC. However
1013 we cannot use the frame PC as-is, because it usually points to
1014 the instruction following the "call", which is sometimes the
1015 first instruction of another function. So we rely on
1016 get_frame_address_in_block() which provides us with a PC which
1017 is guaranteed to be inside the frame's code block. */
1018 s
= find_pc_symtab (get_frame_address_in_block (fi
));
1020 && s
->language
!= current_language
->la_language
1021 && s
->language
!= language_unknown
1022 && language_mode
== language_mode_auto
)
1024 set_language (s
->language
);
1029 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
1030 Always returns a non-NULL value. */
1033 create_new_frame (CORE_ADDR addr
, CORE_ADDR pc
)
1035 struct frame_info
*fi
;
1039 fprintf_unfiltered (gdb_stdlog
,
1040 "{ create_new_frame (addr=0x%s, pc=0x%s) ",
1041 paddr_nz (addr
), paddr_nz (pc
));
1044 fi
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1046 fi
->next
= create_sentinel_frame (get_current_regcache ());
1048 /* Select/initialize both the unwind function and the frame's type
1050 fi
->unwind
= frame_unwind_find_by_frame (fi
, &fi
->prologue_cache
);
1053 deprecated_update_frame_base_hack (fi
, addr
);
1054 deprecated_update_frame_pc_hack (fi
, pc
);
1058 fprintf_unfiltered (gdb_stdlog
, "-> ");
1059 fprint_frame (gdb_stdlog
, fi
);
1060 fprintf_unfiltered (gdb_stdlog
, " }\n");
1066 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
1067 innermost frame). Be careful to not fall off the bottom of the
1068 frame chain and onto the sentinel frame. */
1071 get_next_frame (struct frame_info
*this_frame
)
1073 if (this_frame
->level
> 0)
1074 return this_frame
->next
;
1079 /* Observer for the target_changed event. */
1082 frame_observer_target_changed (struct target_ops
*target
)
1084 reinit_frame_cache ();
1087 /* Flush the entire frame cache. */
1090 reinit_frame_cache (void)
1092 struct frame_info
*fi
;
1094 /* Tear down all frame caches. */
1095 for (fi
= current_frame
; fi
!= NULL
; fi
= fi
->prev
)
1097 if (fi
->prologue_cache
&& fi
->unwind
->dealloc_cache
)
1098 fi
->unwind
->dealloc_cache (fi
, fi
->prologue_cache
);
1099 if (fi
->base_cache
&& fi
->base
->unwind
->dealloc_cache
)
1100 fi
->base
->unwind
->dealloc_cache (fi
, fi
->base_cache
);
1103 /* Since we can't really be sure what the first object allocated was */
1104 obstack_free (&frame_cache_obstack
, 0);
1105 obstack_init (&frame_cache_obstack
);
1107 if (current_frame
!= NULL
)
1108 annotate_frames_invalid ();
1110 current_frame
= NULL
; /* Invalidate cache */
1111 select_frame (NULL
);
1113 fprintf_unfiltered (gdb_stdlog
, "{ reinit_frame_cache () }\n");
1116 /* Find where a register is saved (in memory or another register).
1117 The result of frame_register_unwind is just where it is saved
1118 relative to this particular frame. */
1121 frame_register_unwind_location (struct frame_info
*this_frame
, int regnum
,
1122 int *optimizedp
, enum lval_type
*lvalp
,
1123 CORE_ADDR
*addrp
, int *realnump
)
1125 gdb_assert (this_frame
== NULL
|| this_frame
->level
>= 0);
1127 while (this_frame
!= NULL
)
1129 frame_register_unwind (this_frame
, regnum
, optimizedp
, lvalp
,
1130 addrp
, realnump
, NULL
);
1135 if (*lvalp
!= lval_register
)
1139 this_frame
= get_next_frame (this_frame
);
1143 /* Return a "struct frame_info" corresponding to the frame that called
1144 THIS_FRAME. Returns NULL if there is no such frame.
1146 Unlike get_prev_frame, this function always tries to unwind the
1149 static struct frame_info
*
1150 get_prev_frame_1 (struct frame_info
*this_frame
)
1152 struct frame_info
*prev_frame
;
1153 struct frame_id this_id
;
1154 struct gdbarch
*gdbarch
;
1156 gdb_assert (this_frame
!= NULL
);
1157 gdbarch
= get_frame_arch (this_frame
);
1161 fprintf_unfiltered (gdb_stdlog
, "{ get_prev_frame_1 (this_frame=");
1162 if (this_frame
!= NULL
)
1163 fprintf_unfiltered (gdb_stdlog
, "%d", this_frame
->level
);
1165 fprintf_unfiltered (gdb_stdlog
, "<NULL>");
1166 fprintf_unfiltered (gdb_stdlog
, ") ");
1169 /* Only try to do the unwind once. */
1170 if (this_frame
->prev_p
)
1174 fprintf_unfiltered (gdb_stdlog
, "-> ");
1175 fprint_frame (gdb_stdlog
, this_frame
->prev
);
1176 fprintf_unfiltered (gdb_stdlog
, " // cached \n");
1178 return this_frame
->prev
;
1181 /* If the frame unwinder hasn't been selected yet, we must do so
1182 before setting prev_p; otherwise the check for misbehaved
1183 sniffers will think that this frame's sniffer tried to unwind
1184 further (see frame_cleanup_after_sniffer). */
1185 if (this_frame
->unwind
== NULL
)
1187 = frame_unwind_find_by_frame (this_frame
, &this_frame
->prologue_cache
);
1189 this_frame
->prev_p
= 1;
1190 this_frame
->stop_reason
= UNWIND_NO_REASON
;
1192 /* Check that this frame's ID was valid. If it wasn't, don't try to
1193 unwind to the prev frame. Be careful to not apply this test to
1194 the sentinel frame. */
1195 this_id
= get_frame_id (this_frame
);
1196 if (this_frame
->level
>= 0 && !frame_id_p (this_id
))
1200 fprintf_unfiltered (gdb_stdlog
, "-> ");
1201 fprint_frame (gdb_stdlog
, NULL
);
1202 fprintf_unfiltered (gdb_stdlog
, " // this ID is NULL }\n");
1204 this_frame
->stop_reason
= UNWIND_NULL_ID
;
1208 /* Check that this frame's ID isn't inner to (younger, below, next)
1209 the next frame. This happens when a frame unwind goes backwards.
1210 Exclude signal trampolines (due to sigaltstack the frame ID can
1211 go backwards) and sentinel frames (the test is meaningless). */
1212 if (this_frame
->next
->level
>= 0
1213 && this_frame
->next
->unwind
->type
!= SIGTRAMP_FRAME
1214 && frame_id_inner (get_frame_arch (this_frame
), this_id
,
1215 get_frame_id (this_frame
->next
)))
1219 fprintf_unfiltered (gdb_stdlog
, "-> ");
1220 fprint_frame (gdb_stdlog
, NULL
);
1221 fprintf_unfiltered (gdb_stdlog
, " // this frame ID is inner }\n");
1223 this_frame
->stop_reason
= UNWIND_INNER_ID
;
1227 /* Check that this and the next frame are not identical. If they
1228 are, there is most likely a stack cycle. As with the inner-than
1229 test above, avoid comparing the inner-most and sentinel frames. */
1230 if (this_frame
->level
> 0
1231 && frame_id_eq (this_id
, get_frame_id (this_frame
->next
)))
1235 fprintf_unfiltered (gdb_stdlog
, "-> ");
1236 fprint_frame (gdb_stdlog
, NULL
);
1237 fprintf_unfiltered (gdb_stdlog
, " // this frame has same ID }\n");
1239 this_frame
->stop_reason
= UNWIND_SAME_ID
;
1243 /* Check that this and the next frame do not unwind the PC register
1244 to the same memory location. If they do, then even though they
1245 have different frame IDs, the new frame will be bogus; two
1246 functions can't share a register save slot for the PC. This can
1247 happen when the prologue analyzer finds a stack adjustment, but
1250 This check does assume that the "PC register" is roughly a
1251 traditional PC, even if the gdbarch_unwind_pc method adjusts
1252 it (we do not rely on the value, only on the unwound PC being
1253 dependent on this value). A potential improvement would be
1254 to have the frame prev_pc method and the gdbarch unwind_pc
1255 method set the same lval and location information as
1256 frame_register_unwind. */
1257 if (this_frame
->level
> 0
1258 && gdbarch_pc_regnum (gdbarch
) >= 0
1259 && get_frame_type (this_frame
) == NORMAL_FRAME
1260 && get_frame_type (this_frame
->next
) == NORMAL_FRAME
)
1262 int optimized
, realnum
, nrealnum
;
1263 enum lval_type lval
, nlval
;
1264 CORE_ADDR addr
, naddr
;
1266 frame_register_unwind_location (this_frame
,
1267 gdbarch_pc_regnum (gdbarch
),
1268 &optimized
, &lval
, &addr
, &realnum
);
1269 frame_register_unwind_location (get_next_frame (this_frame
),
1270 gdbarch_pc_regnum (gdbarch
),
1271 &optimized
, &nlval
, &naddr
, &nrealnum
);
1273 if ((lval
== lval_memory
&& lval
== nlval
&& addr
== naddr
)
1274 || (lval
== lval_register
&& lval
== nlval
&& realnum
== nrealnum
))
1278 fprintf_unfiltered (gdb_stdlog
, "-> ");
1279 fprint_frame (gdb_stdlog
, NULL
);
1280 fprintf_unfiltered (gdb_stdlog
, " // no saved PC }\n");
1283 this_frame
->stop_reason
= UNWIND_NO_SAVED_PC
;
1284 this_frame
->prev
= NULL
;
1289 /* Allocate the new frame but do not wire it in to the frame chain.
1290 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
1291 frame->next to pull some fancy tricks (of course such code is, by
1292 definition, recursive). Try to prevent it.
1294 There is no reason to worry about memory leaks, should the
1295 remainder of the function fail. The allocated memory will be
1296 quickly reclaimed when the frame cache is flushed, and the `we've
1297 been here before' check above will stop repeated memory
1298 allocation calls. */
1299 prev_frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1300 prev_frame
->level
= this_frame
->level
+ 1;
1302 /* Don't yet compute ->unwind (and hence ->type). It is computed
1303 on-demand in get_frame_type, frame_register_unwind, and
1306 /* Don't yet compute the frame's ID. It is computed on-demand by
1309 /* The unwound frame ID is validate at the start of this function,
1310 as part of the logic to decide if that frame should be further
1311 unwound, and not here while the prev frame is being created.
1312 Doing this makes it possible for the user to examine a frame that
1313 has an invalid frame ID.
1315 Some very old VAX code noted: [...] For the sake of argument,
1316 suppose that the stack is somewhat trashed (which is one reason
1317 that "info frame" exists). So, return 0 (indicating we don't
1318 know the address of the arglist) if we don't know what frame this
1322 this_frame
->prev
= prev_frame
;
1323 prev_frame
->next
= this_frame
;
1327 fprintf_unfiltered (gdb_stdlog
, "-> ");
1328 fprint_frame (gdb_stdlog
, prev_frame
);
1329 fprintf_unfiltered (gdb_stdlog
, " }\n");
1335 /* Debug routine to print a NULL frame being returned. */
1338 frame_debug_got_null_frame (struct ui_file
*file
,
1339 struct frame_info
*this_frame
,
1344 fprintf_unfiltered (gdb_stdlog
, "{ get_prev_frame (this_frame=");
1345 if (this_frame
!= NULL
)
1346 fprintf_unfiltered (gdb_stdlog
, "%d", this_frame
->level
);
1348 fprintf_unfiltered (gdb_stdlog
, "<NULL>");
1349 fprintf_unfiltered (gdb_stdlog
, ") -> // %s}\n", reason
);
1353 /* Is this (non-sentinel) frame in the "main"() function? */
1356 inside_main_func (struct frame_info
*this_frame
)
1358 struct minimal_symbol
*msymbol
;
1361 if (symfile_objfile
== 0)
1363 msymbol
= lookup_minimal_symbol (main_name (), NULL
, symfile_objfile
);
1364 if (msymbol
== NULL
)
1366 /* Make certain that the code, and not descriptor, address is
1368 maddr
= gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame
),
1369 SYMBOL_VALUE_ADDRESS (msymbol
),
1371 return maddr
== get_frame_func (this_frame
);
1374 /* Test whether THIS_FRAME is inside the process entry point function. */
1377 inside_entry_func (struct frame_info
*this_frame
)
1379 return (get_frame_func (this_frame
) == entry_point_address ());
1382 /* Return a structure containing various interesting information about
1383 the frame that called THIS_FRAME. Returns NULL if there is entier
1384 no such frame or the frame fails any of a set of target-independent
1385 condition that should terminate the frame chain (e.g., as unwinding
1388 This function should not contain target-dependent tests, such as
1389 checking whether the program-counter is zero. */
1392 get_prev_frame (struct frame_info
*this_frame
)
1394 struct frame_info
*prev_frame
;
1396 /* Return the inner-most frame, when the caller passes in NULL. */
1397 /* NOTE: cagney/2002-11-09: Not sure how this would happen. The
1398 caller should have previously obtained a valid frame using
1399 get_selected_frame() and then called this code - only possibility
1400 I can think of is code behaving badly.
1402 NOTE: cagney/2003-01-10: Talk about code behaving badly. Check
1403 block_innermost_frame(). It does the sequence: frame = NULL;
1404 while (1) { frame = get_prev_frame (frame); .... }. Ulgh! Why
1405 it couldn't be written better, I don't know.
1407 NOTE: cagney/2003-01-11: I suspect what is happening in
1408 block_innermost_frame() is, when the target has no state
1409 (registers, memory, ...), it is still calling this function. The
1410 assumption being that this function will return NULL indicating
1411 that a frame isn't possible, rather than checking that the target
1412 has state and then calling get_current_frame() and
1413 get_prev_frame(). This is a guess mind. */
1414 if (this_frame
== NULL
)
1416 /* NOTE: cagney/2002-11-09: There was a code segment here that
1417 would error out when CURRENT_FRAME was NULL. The comment
1418 that went with it made the claim ...
1420 ``This screws value_of_variable, which just wants a nice
1421 clean NULL return from block_innermost_frame if there are no
1422 frames. I don't think I've ever seen this message happen
1423 otherwise. And returning NULL here is a perfectly legitimate
1426 Per the above, this code shouldn't even be called with a NULL
1428 frame_debug_got_null_frame (gdb_stdlog
, this_frame
, "this_frame NULL");
1429 return current_frame
;
1432 /* There is always a frame. If this assertion fails, suspect that
1433 something should be calling get_selected_frame() or
1434 get_current_frame(). */
1435 gdb_assert (this_frame
!= NULL
);
1437 /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much
1438 sense to stop unwinding at a dummy frame. One place where a dummy
1439 frame may have an address "inside_main_func" is on HPUX. On HPUX, the
1440 pcsqh register (space register for the instruction at the head of the
1441 instruction queue) cannot be written directly; the only way to set it
1442 is to branch to code that is in the target space. In order to implement
1443 frame dummies on HPUX, the called function is made to jump back to where
1444 the inferior was when the user function was called. If gdb was inside
1445 the main function when we created the dummy frame, the dummy frame will
1446 point inside the main function. */
1447 if (this_frame
->level
>= 0
1448 && get_frame_type (this_frame
) != DUMMY_FRAME
1449 && !backtrace_past_main
1450 && inside_main_func (this_frame
))
1451 /* Don't unwind past main(). Note, this is done _before_ the
1452 frame has been marked as previously unwound. That way if the
1453 user later decides to enable unwinds past main(), that will
1454 automatically happen. */
1456 frame_debug_got_null_frame (gdb_stdlog
, this_frame
, "inside main func");
1460 /* If the user's backtrace limit has been exceeded, stop. We must
1461 add two to the current level; one of those accounts for backtrace_limit
1462 being 1-based and the level being 0-based, and the other accounts for
1463 the level of the new frame instead of the level of the current
1465 if (this_frame
->level
+ 2 > backtrace_limit
)
1467 frame_debug_got_null_frame (gdb_stdlog
, this_frame
,
1468 "backtrace limit exceeded");
1472 /* If we're already inside the entry function for the main objfile,
1473 then it isn't valid. Don't apply this test to a dummy frame -
1474 dummy frame PCs typically land in the entry func. Don't apply
1475 this test to the sentinel frame. Sentinel frames should always
1476 be allowed to unwind. */
1477 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() -
1478 wasn't checking for "main" in the minimal symbols. With that
1479 fixed asm-source tests now stop in "main" instead of halting the
1480 backtrace in weird and wonderful ways somewhere inside the entry
1481 file. Suspect that tests for inside the entry file/func were
1482 added to work around that (now fixed) case. */
1483 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right)
1484 suggested having the inside_entry_func test use the
1485 inside_main_func() msymbol trick (along with entry_point_address()
1486 I guess) to determine the address range of the start function.
1487 That should provide a far better stopper than the current
1489 /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler
1490 applied tail-call optimizations to main so that a function called
1491 from main returns directly to the caller of main. Since we don't
1492 stop at main, we should at least stop at the entry point of the
1494 if (!backtrace_past_entry
1495 && get_frame_type (this_frame
) != DUMMY_FRAME
&& this_frame
->level
>= 0
1496 && inside_entry_func (this_frame
))
1498 frame_debug_got_null_frame (gdb_stdlog
, this_frame
, "inside entry func");
1502 /* Assume that the only way to get a zero PC is through something
1503 like a SIGSEGV or a dummy frame, and hence that NORMAL frames
1504 will never unwind a zero PC. */
1505 if (this_frame
->level
> 0
1506 && get_frame_type (this_frame
) == NORMAL_FRAME
1507 && get_frame_type (get_next_frame (this_frame
)) == NORMAL_FRAME
1508 && get_frame_pc (this_frame
) == 0)
1510 frame_debug_got_null_frame (gdb_stdlog
, this_frame
, "zero PC");
1514 return get_prev_frame_1 (this_frame
);
1518 get_frame_pc (struct frame_info
*frame
)
1520 gdb_assert (frame
->next
!= NULL
);
1521 return frame_pc_unwind (frame
->next
);
1524 /* Return an address that falls within THIS_FRAME's code block. */
1527 get_frame_address_in_block (struct frame_info
*this_frame
)
1529 /* A draft address. */
1530 CORE_ADDR pc
= get_frame_pc (this_frame
);
1532 struct frame_info
*next_frame
= this_frame
->next
;
1534 /* Calling get_frame_pc returns the resume address for THIS_FRAME.
1535 Normally the resume address is inside the body of the function
1536 associated with THIS_FRAME, but there is a special case: when
1537 calling a function which the compiler knows will never return
1538 (for instance abort), the call may be the very last instruction
1539 in the calling function. The resume address will point after the
1540 call and may be at the beginning of a different function
1543 If THIS_FRAME is a signal frame or dummy frame, then we should
1544 not adjust the unwound PC. For a dummy frame, GDB pushed the
1545 resume address manually onto the stack. For a signal frame, the
1546 OS may have pushed the resume address manually and invoked the
1547 handler (e.g. GNU/Linux), or invoked the trampoline which called
1548 the signal handler - but in either case the signal handler is
1549 expected to return to the trampoline. So in both of these
1550 cases we know that the resume address is executable and
1551 related. So we only need to adjust the PC if THIS_FRAME
1552 is a normal function.
1554 If the program has been interrupted while THIS_FRAME is current,
1555 then clearly the resume address is inside the associated
1556 function. There are three kinds of interruption: debugger stop
1557 (next frame will be SENTINEL_FRAME), operating system
1558 signal or exception (next frame will be SIGTRAMP_FRAME),
1559 or debugger-induced function call (next frame will be
1560 DUMMY_FRAME). So we only need to adjust the PC if
1561 NEXT_FRAME is a normal function.
1563 We check the type of NEXT_FRAME first, since it is already
1564 known; frame type is determined by the unwinder, and since
1565 we have THIS_FRAME we've already selected an unwinder for
1567 if (get_frame_type (next_frame
) == NORMAL_FRAME
1568 && get_frame_type (this_frame
) == NORMAL_FRAME
)
1575 pc_notcurrent (struct frame_info
*frame
)
1577 /* If FRAME is not the innermost frame, that normally means that
1578 FRAME->pc points at the return instruction (which is *after* the
1579 call instruction), and we want to get the line containing the
1580 call (because the call is where the user thinks the program is).
1581 However, if the next frame is either a SIGTRAMP_FRAME or a
1582 DUMMY_FRAME, then the next frame will contain a saved interrupt
1583 PC and such a PC indicates the current (rather than next)
1584 instruction/line, consequently, for such cases, want to get the
1585 line containing fi->pc. */
1586 struct frame_info
*next
= get_next_frame (frame
);
1587 int notcurrent
= (next
!= NULL
&& get_frame_type (next
) == NORMAL_FRAME
);
1592 find_frame_sal (struct frame_info
*frame
, struct symtab_and_line
*sal
)
1594 (*sal
) = find_pc_line (get_frame_pc (frame
), pc_notcurrent (frame
));
1597 /* Per "frame.h", return the ``address'' of the frame. Code should
1598 really be using get_frame_id(). */
1600 get_frame_base (struct frame_info
*fi
)
1602 return get_frame_id (fi
).stack_addr
;
1605 /* High-level offsets into the frame. Used by the debug info. */
1608 get_frame_base_address (struct frame_info
*fi
)
1610 if (get_frame_type (fi
) != NORMAL_FRAME
)
1612 if (fi
->base
== NULL
)
1613 fi
->base
= frame_base_find_by_frame (fi
);
1614 /* Sneaky: If the low-level unwind and high-level base code share a
1615 common unwinder, let them share the prologue cache. */
1616 if (fi
->base
->unwind
== fi
->unwind
)
1617 return fi
->base
->this_base (fi
, &fi
->prologue_cache
);
1618 return fi
->base
->this_base (fi
, &fi
->base_cache
);
1622 get_frame_locals_address (struct frame_info
*fi
)
1625 if (get_frame_type (fi
) != NORMAL_FRAME
)
1627 /* If there isn't a frame address method, find it. */
1628 if (fi
->base
== NULL
)
1629 fi
->base
= frame_base_find_by_frame (fi
);
1630 /* Sneaky: If the low-level unwind and high-level base code share a
1631 common unwinder, let them share the prologue cache. */
1632 if (fi
->base
->unwind
== fi
->unwind
)
1633 return fi
->base
->this_locals (fi
, &fi
->prologue_cache
);
1634 return fi
->base
->this_locals (fi
, &fi
->base_cache
);
1638 get_frame_args_address (struct frame_info
*fi
)
1641 if (get_frame_type (fi
) != NORMAL_FRAME
)
1643 /* If there isn't a frame address method, find it. */
1644 if (fi
->base
== NULL
)
1645 fi
->base
= frame_base_find_by_frame (fi
);
1646 /* Sneaky: If the low-level unwind and high-level base code share a
1647 common unwinder, let them share the prologue cache. */
1648 if (fi
->base
->unwind
== fi
->unwind
)
1649 return fi
->base
->this_args (fi
, &fi
->prologue_cache
);
1650 return fi
->base
->this_args (fi
, &fi
->base_cache
);
1653 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
1654 or -1 for a NULL frame. */
1657 frame_relative_level (struct frame_info
*fi
)
1666 get_frame_type (struct frame_info
*frame
)
1668 if (frame
->unwind
== NULL
)
1669 /* Initialize the frame's unwinder because that's what
1670 provides the frame's type. */
1671 frame
->unwind
= frame_unwind_find_by_frame (frame
, &frame
->prologue_cache
);
1672 return frame
->unwind
->type
;
1676 deprecated_update_frame_pc_hack (struct frame_info
*frame
, CORE_ADDR pc
)
1679 fprintf_unfiltered (gdb_stdlog
,
1680 "{ deprecated_update_frame_pc_hack (frame=%d,pc=0x%s) }\n",
1681 frame
->level
, paddr_nz (pc
));
1682 /* NOTE: cagney/2003-03-11: Some architectures (e.g., Arm) are
1683 maintaining a locally allocated frame object. Since such frames
1684 are not in the frame chain, it isn't possible to assume that the
1685 frame has a next. Sigh. */
1686 if (frame
->next
!= NULL
)
1688 /* While we're at it, update this frame's cached PC value, found
1689 in the next frame. Oh for the day when "struct frame_info"
1690 is opaque and this hack on hack can just go away. */
1691 frame
->next
->prev_pc
.value
= pc
;
1692 frame
->next
->prev_pc
.p
= 1;
1697 deprecated_update_frame_base_hack (struct frame_info
*frame
, CORE_ADDR base
)
1700 fprintf_unfiltered (gdb_stdlog
,
1701 "{ deprecated_update_frame_base_hack (frame=%d,base=0x%s) }\n",
1702 frame
->level
, paddr_nz (base
));
1703 /* See comment in "frame.h". */
1704 frame
->this_id
.value
.stack_addr
= base
;
1707 /* Memory access methods. */
1710 get_frame_memory (struct frame_info
*this_frame
, CORE_ADDR addr
,
1711 gdb_byte
*buf
, int len
)
1713 read_memory (addr
, buf
, len
);
1717 get_frame_memory_signed (struct frame_info
*this_frame
, CORE_ADDR addr
,
1720 return read_memory_integer (addr
, len
);
1724 get_frame_memory_unsigned (struct frame_info
*this_frame
, CORE_ADDR addr
,
1727 return read_memory_unsigned_integer (addr
, len
);
1731 safe_frame_unwind_memory (struct frame_info
*this_frame
,
1732 CORE_ADDR addr
, gdb_byte
*buf
, int len
)
1734 /* NOTE: target_read_memory returns zero on success! */
1735 return !target_read_memory (addr
, buf
, len
);
1738 /* Architecture method. */
1741 get_frame_arch (struct frame_info
*this_frame
)
1743 return current_gdbarch
;
1746 /* Stack pointer methods. */
1749 get_frame_sp (struct frame_info
*this_frame
)
1751 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
1752 /* Normality - an architecture that provides a way of obtaining any
1753 frame inner-most address. */
1754 if (gdbarch_unwind_sp_p (gdbarch
))
1755 /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
1756 operate on THIS_FRAME now. */
1757 return gdbarch_unwind_sp (gdbarch
, this_frame
->next
);
1758 /* Now things are really are grim. Hope that the value returned by
1759 the gdbarch_sp_regnum register is meaningful. */
1760 if (gdbarch_sp_regnum (gdbarch
) >= 0)
1761 return get_frame_register_unsigned (this_frame
,
1762 gdbarch_sp_regnum (gdbarch
));
1763 internal_error (__FILE__
, __LINE__
, _("Missing unwind SP method"));
1766 /* Return the reason why we can't unwind past FRAME. */
1768 enum unwind_stop_reason
1769 get_frame_unwind_stop_reason (struct frame_info
*frame
)
1771 /* If we haven't tried to unwind past this point yet, then assume
1772 that unwinding would succeed. */
1773 if (frame
->prev_p
== 0)
1774 return UNWIND_NO_REASON
;
1776 /* Otherwise, we set a reason when we succeeded (or failed) to
1778 return frame
->stop_reason
;
1781 /* Return a string explaining REASON. */
1784 frame_stop_reason_string (enum unwind_stop_reason reason
)
1788 case UNWIND_NULL_ID
:
1789 return _("unwinder did not report frame ID");
1791 case UNWIND_INNER_ID
:
1792 return _("previous frame inner to this frame (corrupt stack?)");
1794 case UNWIND_SAME_ID
:
1795 return _("previous frame identical to this frame (corrupt stack?)");
1797 case UNWIND_NO_SAVED_PC
:
1798 return _("frame did not save the PC");
1800 case UNWIND_NO_REASON
:
1801 case UNWIND_FIRST_ERROR
:
1803 internal_error (__FILE__
, __LINE__
,
1804 "Invalid frame stop reason");
1808 /* Clean up after a failed (wrong unwinder) attempt to unwind past
1812 frame_cleanup_after_sniffer (void *arg
)
1814 struct frame_info
*frame
= arg
;
1816 /* The sniffer should not allocate a prologue cache if it did not
1817 match this frame. */
1818 gdb_assert (frame
->prologue_cache
== NULL
);
1820 /* No sniffer should extend the frame chain; sniff based on what is
1822 gdb_assert (!frame
->prev_p
);
1824 /* The sniffer should not check the frame's ID; that's circular. */
1825 gdb_assert (!frame
->this_id
.p
);
1827 /* Clear cached fields dependent on the unwinder.
1829 The previous PC is independent of the unwinder, but the previous
1830 function is not (see get_frame_address_in_block). */
1831 frame
->prev_func
.p
= 0;
1832 frame
->prev_func
.addr
= 0;
1834 /* Discard the unwinder last, so that we can easily find it if an assertion
1835 in this function triggers. */
1836 frame
->unwind
= NULL
;
1839 /* Set FRAME's unwinder temporarily, so that we can call a sniffer.
1840 Return a cleanup which should be called if unwinding fails, and
1841 discarded if it succeeds. */
1844 frame_prepare_for_sniffer (struct frame_info
*frame
,
1845 const struct frame_unwind
*unwind
)
1847 gdb_assert (frame
->unwind
== NULL
);
1848 frame
->unwind
= unwind
;
1849 return make_cleanup (frame_cleanup_after_sniffer
, frame
);
1852 extern initialize_file_ftype _initialize_frame
; /* -Wmissing-prototypes */
1854 static struct cmd_list_element
*set_backtrace_cmdlist
;
1855 static struct cmd_list_element
*show_backtrace_cmdlist
;
1858 set_backtrace_cmd (char *args
, int from_tty
)
1860 help_list (set_backtrace_cmdlist
, "set backtrace ", -1, gdb_stdout
);
1864 show_backtrace_cmd (char *args
, int from_tty
)
1866 cmd_show_list (show_backtrace_cmdlist
, from_tty
, "");
1870 _initialize_frame (void)
1872 obstack_init (&frame_cache_obstack
);
1874 observer_attach_target_changed (frame_observer_target_changed
);
1876 add_prefix_cmd ("backtrace", class_maintenance
, set_backtrace_cmd
, _("\
1877 Set backtrace specific variables.\n\
1878 Configure backtrace variables such as the backtrace limit"),
1879 &set_backtrace_cmdlist
, "set backtrace ",
1880 0/*allow-unknown*/, &setlist
);
1881 add_prefix_cmd ("backtrace", class_maintenance
, show_backtrace_cmd
, _("\
1882 Show backtrace specific variables\n\
1883 Show backtrace variables such as the backtrace limit"),
1884 &show_backtrace_cmdlist
, "show backtrace ",
1885 0/*allow-unknown*/, &showlist
);
1887 add_setshow_boolean_cmd ("past-main", class_obscure
,
1888 &backtrace_past_main
, _("\
1889 Set whether backtraces should continue past \"main\"."), _("\
1890 Show whether backtraces should continue past \"main\"."), _("\
1891 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
1892 the backtrace at \"main\". Set this variable if you need to see the rest\n\
1893 of the stack trace."),
1895 show_backtrace_past_main
,
1896 &set_backtrace_cmdlist
,
1897 &show_backtrace_cmdlist
);
1899 add_setshow_boolean_cmd ("past-entry", class_obscure
,
1900 &backtrace_past_entry
, _("\
1901 Set whether backtraces should continue past the entry point of a program."),
1903 Show whether backtraces should continue past the entry point of a program."),
1905 Normally there are no callers beyond the entry point of a program, so GDB\n\
1906 will terminate the backtrace there. Set this variable if you need to see \n\
1907 the rest of the stack trace."),
1909 show_backtrace_past_entry
,
1910 &set_backtrace_cmdlist
,
1911 &show_backtrace_cmdlist
);
1913 add_setshow_integer_cmd ("limit", class_obscure
,
1914 &backtrace_limit
, _("\
1915 Set an upper bound on the number of backtrace levels."), _("\
1916 Show the upper bound on the number of backtrace levels."), _("\
1917 No more than the specified number of frames can be displayed or examined.\n\
1918 Zero is unlimited."),
1920 show_backtrace_limit
,
1921 &set_backtrace_cmdlist
,
1922 &show_backtrace_cmdlist
);
1924 /* Debug this files internals. */
1925 add_setshow_zinteger_cmd ("frame", class_maintenance
, &frame_debug
, _("\
1926 Set frame debugging."), _("\
1927 Show frame debugging."), _("\
1928 When non-zero, frame specific internal debugging is enabled."),
1931 &setdebuglist
, &showdebuglist
);