1 /* Cache and manage frames for GDB, the GNU debugger.
3 Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000,
4 2001, 2002, 2003 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 2 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, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
27 #include "inferior.h" /* for inferior_ptid */
29 #include "gdb_assert.h"
30 #include "gdb_string.h"
31 #include "builtin-regs.h"
32 #include "gdb_obstack.h"
33 #include "dummy-frame.h"
34 #include "sentinel-frame.h"
38 #include "frame-unwind.h"
39 #include "frame-base.h"
43 /* Flag to control debugging. */
45 static int frame_debug
;
47 /* Flag to indicate whether backtraces should stop at main. */
49 static int backtrace_below_main
;
51 /* Return a frame uniq ID that can be used to, later, re-find the
55 get_frame_id (struct frame_info
*fi
)
63 gdb_assert (!legacy_frame_p (current_gdbarch
));
64 /* Find THIS frame's ID. */
65 fi
->unwind
->this_id (fi
->next
, &fi
->prologue_cache
, &fi
->id
);
67 /* FIXME: cagney/2002-12-18: Instead of this hack, should only
68 store the frame ID in PREV_FRAME. Unfortunatly, some
69 architectures (HP/UX) still reply on EXTRA_FRAME_INFO and,
70 hence, still poke at the "struct frame_info" object directly. */
71 fi
->frame
= fi
->id
.base
;
73 return frame_id_build (fi
->frame
, get_frame_pc (fi
));
76 const struct frame_id null_frame_id
; /* All zeros. */
79 frame_id_build (CORE_ADDR base
, CORE_ADDR func_or_pc
)
88 frame_id_p (struct frame_id l
)
90 /* The .func can be NULL but the .base cannot. */
95 frame_id_eq (struct frame_id l
, struct frame_id r
)
97 /* If .base is different, the frames are different. */
100 /* Add a test to check that the frame ID's are for the same function
106 frame_id_inner (struct frame_id l
, struct frame_id r
)
108 /* Only return non-zero when strictly inner than. Note that, per
109 comment in "frame.h", there is some fuzz here. Frameless
110 functions are not strictly inner than (same .base but different
112 return INNER_THAN (l
.base
, r
.base
);
116 frame_find_by_id (struct frame_id id
)
118 struct frame_info
*frame
;
120 /* ZERO denotes the null frame, let the caller decide what to do
121 about it. Should it instead return get_current_frame()? */
122 if (!frame_id_p (id
))
125 for (frame
= get_current_frame ();
127 frame
= get_prev_frame (frame
))
129 struct frame_id
this = get_frame_id (frame
);
130 if (frame_id_eq (id
, this))
131 /* An exact match. */
133 if (frame_id_inner (id
, this))
136 /* Either, we're not yet gone far enough out along the frame
137 chain (inner(this,id), or we're comparing frameless functions
138 (same .base, different .func, no test available). Struggle
139 on until we've definitly gone to far. */
145 frame_pc_unwind (struct frame_info
*this_frame
)
147 if (!this_frame
->pc_unwind_cache_p
)
150 if (gdbarch_unwind_pc_p (current_gdbarch
))
152 /* The right way. The `pure' way. The one true way. This
153 method depends solely on the register-unwind code to
154 determine the value of registers in THIS frame, and hence
155 the value of this frame's PC (resume address). A typical
156 implementation is no more than:
158 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf);
159 return extract_address (buf, size of ISA_PC_REGNUM);
161 Note: this method is very heavily dependent on a correct
162 register-unwind implementation, it pays to fix that
163 method first; this method is frame type agnostic, since
164 it only deals with register values, it works with any
165 frame. This is all in stark contrast to the old
166 FRAME_SAVED_PC which would try to directly handle all the
167 different ways that a PC could be unwound. */
168 pc
= gdbarch_unwind_pc (current_gdbarch
, this_frame
);
170 else if (this_frame
->level
< 0)
172 /* FIXME: cagney/2003-03-06: Old code and and a sentinel
173 frame. Do like was always done. Fetch the PC's value
174 direct from the global registers array (via read_pc).
175 This assumes that this frame belongs to the current
176 global register cache. The assumption is dangerous. */
179 else if (DEPRECATED_FRAME_SAVED_PC_P ())
181 /* FIXME: cagney/2003-03-06: Old code, but not a sentinel
182 frame. Do like was always done. Note that this method,
183 unlike unwind_pc(), tries to handle all the different
184 frame cases directly. It fails. */
185 pc
= DEPRECATED_FRAME_SAVED_PC (this_frame
);
188 internal_error (__FILE__
, __LINE__
, "No gdbarch_unwind_pc method");
189 this_frame
->pc_unwind_cache
= pc
;
190 this_frame
->pc_unwind_cache_p
= 1;
192 return this_frame
->pc_unwind_cache
;
196 do_frame_unwind_register (void *src
, int regnum
, void *buf
)
198 frame_unwind_register (src
, regnum
, buf
);
203 frame_pop (struct frame_info
*this_frame
)
205 struct regcache
*scratch_regcache
;
206 struct cleanup
*cleanups
;
208 if (DEPRECATED_POP_FRAME_P ())
210 /* A legacy architecture that has implemented a custom pop
211 function. All new architectures should instead be using the
212 generic code below. */
213 DEPRECATED_POP_FRAME
;
217 /* Make a copy of all the register values unwound from this
218 frame. Save them in a scratch buffer so that there isn't a
219 race betweening trying to extract the old values from the
220 current_regcache while, at the same time writing new values
221 into that same cache. */
222 struct regcache
*scratch
= regcache_xmalloc (current_gdbarch
);
223 struct cleanup
*cleanups
= make_cleanup_regcache_xfree (scratch
);
224 regcache_save (scratch
, do_frame_unwind_register
, this_frame
);
225 /* FIXME: cagney/2003-03-16: It should be possible to tell the
226 target's register cache that it is about to be hit with a
227 burst register transfer and that the sequence of register
228 writes should be batched. The pair target_prepare_to_store()
229 and target_store_registers() kind of suggest this
230 functionality. Unfortunatly, they don't implement it. Their
231 lack of a formal definition can lead to targets writing back
232 bogus values (arguably a bug in the target code mind). */
233 /* Now copy those saved registers into the current regcache.
234 Here, regcache_cpy() calls regcache_restore(). */
235 regcache_cpy (current_regcache
, scratch
);
236 do_cleanups (cleanups
);
238 /* We've made right mess of GDB's local state, just discard
240 flush_cached_frames ();
244 frame_register_unwind (struct frame_info
*frame
, int regnum
,
245 int *optimizedp
, enum lval_type
*lvalp
,
246 CORE_ADDR
*addrp
, int *realnump
, void *bufferp
)
248 struct frame_unwind_cache
*cache
;
250 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
251 that the value proper does not need to be fetched. */
252 gdb_assert (optimizedp
!= NULL
);
253 gdb_assert (lvalp
!= NULL
);
254 gdb_assert (addrp
!= NULL
);
255 gdb_assert (realnump
!= NULL
);
256 /* gdb_assert (bufferp != NULL); */
258 /* NOTE: cagney/2002-11-27: A program trying to unwind a NULL frame
259 is broken. There is always a frame. If there, for some reason,
260 isn't, there is some pretty busted code as it should have
261 detected the problem before calling here. */
262 gdb_assert (frame
!= NULL
);
264 /* Ask this frame to unwind its register. See comment in
265 "frame-unwind.h" for why NEXT frame and this unwind cace are
267 frame
->unwind
->prev_register (frame
->next
, &frame
->prologue_cache
, regnum
,
268 optimizedp
, lvalp
, addrp
, realnump
, bufferp
);
273 frame_register (struct frame_info
*frame
, int regnum
,
274 int *optimizedp
, enum lval_type
*lvalp
,
275 CORE_ADDR
*addrp
, int *realnump
, void *bufferp
)
277 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
278 that the value proper does not need to be fetched. */
279 gdb_assert (optimizedp
!= NULL
);
280 gdb_assert (lvalp
!= NULL
);
281 gdb_assert (addrp
!= NULL
);
282 gdb_assert (realnump
!= NULL
);
283 /* gdb_assert (bufferp != NULL); */
285 /* Ulgh! Old code that, for lval_register, sets ADDRP to the offset
286 of the register in the register cache. It should instead return
287 the REGNUM corresponding to that register. Translate the . */
288 if (DEPRECATED_GET_SAVED_REGISTER_P ())
290 DEPRECATED_GET_SAVED_REGISTER (bufferp
, optimizedp
, addrp
, frame
,
292 /* Compute the REALNUM if the caller wants it. */
293 if (*lvalp
== lval_register
)
296 for (regnum
= 0; regnum
< NUM_REGS
+ NUM_PSEUDO_REGS
; regnum
++)
298 if (*addrp
== register_offset_hack (current_gdbarch
, regnum
))
304 internal_error (__FILE__
, __LINE__
,
305 "Failed to compute the register number corresponding"
306 " to 0x%s", paddr_d (*addrp
));
312 /* Obtain the register value by unwinding the register from the next
313 (more inner frame). */
314 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
315 frame_register_unwind (frame
->next
, regnum
, optimizedp
, lvalp
, addrp
,
320 frame_unwind_register (struct frame_info
*frame
, int regnum
, void *buf
)
326 frame_register_unwind (frame
, regnum
, &optimized
, &lval
, &addr
,
331 frame_unwind_signed_register (struct frame_info
*frame
, int regnum
,
334 void *buf
= alloca (MAX_REGISTER_RAW_SIZE
);
335 frame_unwind_register (frame
, regnum
, buf
);
336 (*val
) = extract_signed_integer (buf
, REGISTER_VIRTUAL_SIZE (regnum
));
340 frame_unwind_unsigned_register (struct frame_info
*frame
, int regnum
,
343 void *buf
= alloca (MAX_REGISTER_RAW_SIZE
);
344 frame_unwind_register (frame
, regnum
, buf
);
345 (*val
) = extract_unsigned_integer (buf
, REGISTER_VIRTUAL_SIZE (regnum
));
349 frame_read_register (struct frame_info
*frame
, int regnum
, void *buf
)
351 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
352 frame_unwind_register (frame
->next
, regnum
, buf
);
356 frame_read_unsigned_register (struct frame_info
*frame
, int regnum
,
359 /* NOTE: cagney/2002-10-31: There is a bit of dogma here - there is
360 always a frame. Both this, and the equivalent
361 frame_read_signed_register() function, can only be called with a
362 valid frame. If, for some reason, this function is called
363 without a frame then the problem isn't here, but rather in the
364 caller. It should of first created a frame and then passed that
366 /* NOTE: cagney/2002-10-31: As a side bar, keep in mind that the
367 ``current_frame'' should not be treated as a special case. While
368 ``get_next_frame (current_frame) == NULL'' currently holds, it
369 should, as far as possible, not be relied upon. In the future,
370 ``get_next_frame (current_frame)'' may instead simply return a
371 normal frame object that simply always gets register values from
372 the register cache. Consequently, frame code should try to avoid
373 tests like ``if get_next_frame() == NULL'' and instead just rely
374 on recursive frame calls (like the below code) when manipulating
376 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
377 frame_unwind_unsigned_register (frame
->next
, regnum
, val
);
381 frame_read_signed_register (struct frame_info
*frame
, int regnum
,
384 /* See note above in frame_read_unsigned_register(). */
385 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
386 frame_unwind_signed_register (frame
->next
, regnum
, val
);
390 generic_unwind_get_saved_register (char *raw_buffer
,
393 struct frame_info
*frame
,
395 enum lval_type
*lvalp
)
400 enum lval_type lvalx
;
402 if (!target_has_registers
)
403 error ("No registers.");
405 /* Keep things simple, ensure that all the pointers (except valuep)
407 if (optimizedp
== NULL
)
408 optimizedp
= &optimizedx
;
414 gdb_assert (frame
!= NULL
&& frame
->next
!= NULL
);
415 frame_register_unwind (frame
->next
, regnum
, optimizedp
, lvalp
, addrp
,
416 &realnumx
, raw_buffer
);
419 /* frame_register_read ()
421 Find and return the value of REGNUM for the specified stack frame.
422 The number of bytes copied is REGISTER_RAW_SIZE (REGNUM).
424 Returns 0 if the register value could not be found. */
427 frame_register_read (struct frame_info
*frame
, int regnum
, void *myaddr
)
433 frame_register (frame
, regnum
, &optimized
, &lval
, &addr
, &realnum
, myaddr
);
435 /* FIXME: cagney/2002-05-15: This test, is just bogus.
437 It indicates that the target failed to supply a value for a
438 register because it was "not available" at this time. Problem
439 is, the target still has the register and so get saved_register()
440 may be returning a value saved on the stack. */
442 if (register_cached (regnum
) < 0)
443 return 0; /* register value not available */
449 /* Map between a frame register number and its name. A frame register
450 space is a superset of the cooked register space --- it also
451 includes builtin registers. */
454 frame_map_name_to_regnum (const char *name
, int len
)
461 /* Search register name space. */
462 for (i
= 0; i
< NUM_REGS
+ NUM_PSEUDO_REGS
; i
++)
463 if (REGISTER_NAME (i
) && len
== strlen (REGISTER_NAME (i
))
464 && strncmp (name
, REGISTER_NAME (i
), len
) == 0)
469 /* Try builtin registers. */
470 i
= builtin_reg_map_name_to_regnum (name
, len
);
473 /* A builtin register doesn't fall into the architecture's
475 gdb_assert (i
>= NUM_REGS
+ NUM_PSEUDO_REGS
);
483 frame_map_regnum_to_name (int regnum
)
487 if (regnum
< NUM_REGS
+ NUM_PSEUDO_REGS
)
488 return REGISTER_NAME (regnum
);
489 return builtin_reg_map_regnum_to_name (regnum
);
492 /* Create a sentinel frame. */
495 create_sentinel_frame (struct regcache
*regcache
)
497 struct frame_info
*frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
498 frame
->type
= NORMAL_FRAME
;
500 /* Explicitly initialize the sentinel frame's cache. Provide it
501 with the underlying regcache. In the future additional
502 information, such as the frame's thread will be added. */
503 frame
->prologue_cache
= sentinel_frame_cache (regcache
);
504 /* For the moment there is only one sentinel frame implementation. */
505 frame
->unwind
= sentinel_frame_unwind
;
506 /* Link this frame back to itself. The frame is self referential
507 (the unwound PC is the same as the pc), so make it so. */
509 /* Always unwind the PC as part of creating this frame. This
510 ensures that the frame's PC points at something valid. */
511 /* FIXME: cagney/2003-01-10: Problem here. Unwinding a sentinel
512 frame's PC may require information such as the frame's thread's
513 stop reason. Is it possible to get to that? */
514 /* FIXME: cagney/2003-04-04: Once ->pc is eliminated, this
515 assignment can go away. */
516 frame
->pc
= frame_pc_unwind (frame
);
517 /* Make the sentinel frame's ID valid, but invalid. That way all
518 comparisons with it should fail. */
520 frame
->id
= null_frame_id
;
524 /* Info about the innermost stack frame (contents of FP register) */
526 static struct frame_info
*current_frame
;
528 /* Cache for frame addresses already read by gdb. Valid only while
529 inferior is stopped. Control variables for the frame cache should
530 be local to this module. */
532 static struct obstack frame_cache_obstack
;
535 frame_obstack_zalloc (unsigned long size
)
537 void *data
= obstack_alloc (&frame_cache_obstack
, size
);
538 memset (data
, 0, size
);
543 frame_saved_regs_zalloc (struct frame_info
*fi
)
545 fi
->saved_regs
= (CORE_ADDR
*)
546 frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS
);
547 return fi
->saved_regs
;
551 get_frame_saved_regs (struct frame_info
*fi
)
553 return fi
->saved_regs
;
556 /* Return the innermost (currently executing) stack frame. This is
557 split into two functions. The function unwind_to_current_frame()
558 is wrapped in catch exceptions so that, even when the unwind of the
559 sentinel frame fails, the function still returns a stack frame. */
562 unwind_to_current_frame (struct ui_out
*ui_out
, void *args
)
564 struct frame_info
*frame
= get_prev_frame (args
);
565 /* A sentinel frame can fail to unwind, eg, because it's PC value
566 lands in somewhere like start. */
569 current_frame
= frame
;
574 get_current_frame (void)
576 /* First check, and report, the lack of registers. Having GDB
577 report "No stack!" or "No memory" when the target doesn't even
578 have registers is very confusing. Besides, "printcmd.exp"
579 explicitly checks that ``print $pc'' with no registers prints "No
581 if (!target_has_registers
)
582 error ("No registers.");
583 if (!target_has_stack
)
585 if (!target_has_memory
)
586 error ("No memory.");
587 if (current_frame
== NULL
)
589 struct frame_info
*sentinel_frame
=
590 create_sentinel_frame (current_regcache
);
591 if (catch_exceptions (uiout
, unwind_to_current_frame
, sentinel_frame
,
592 NULL
, RETURN_MASK_ERROR
) != 0)
594 /* Oops! Fake a current frame? Is this useful? It has a PC
595 of zero, for instance. */
596 current_frame
= sentinel_frame
;
599 return current_frame
;
602 /* The "selected" stack frame is used by default for local and arg
603 access. May be zero, for no selected frame. */
605 struct frame_info
*deprecated_selected_frame
;
607 /* Return the selected frame. Always non-null (unless there isn't an
608 inferior sufficient for creating a frame) in which case an error is
612 get_selected_frame (void)
614 if (deprecated_selected_frame
== NULL
)
615 /* Hey! Don't trust this. It should really be re-finding the
616 last selected frame of the currently selected thread. This,
617 though, is better than nothing. */
618 select_frame (get_current_frame ());
619 /* There is always a frame. */
620 gdb_assert (deprecated_selected_frame
!= NULL
);
621 return deprecated_selected_frame
;
624 /* Select frame FI (or NULL - to invalidate the current frame). */
627 select_frame (struct frame_info
*fi
)
629 register struct symtab
*s
;
631 deprecated_selected_frame
= fi
;
632 /* NOTE: cagney/2002-05-04: FI can be NULL. This occures when the
633 frame is being invalidated. */
634 if (selected_frame_level_changed_hook
)
635 selected_frame_level_changed_hook (frame_relative_level (fi
));
637 /* FIXME: kseitz/2002-08-28: It would be nice to call
638 selected_frame_level_changed_event right here, but due to limitations
639 in the current interfaces, we would end up flooding UIs with events
640 because select_frame is used extensively internally.
642 Once we have frame-parameterized frame (and frame-related) commands,
643 the event notification can be moved here, since this function will only
644 be called when the users selected frame is being changed. */
646 /* Ensure that symbols for this frame are read in. Also, determine the
647 source language of this frame, and switch to it if desired. */
650 s
= find_pc_symtab (get_frame_pc (fi
));
652 && s
->language
!= current_language
->la_language
653 && s
->language
!= language_unknown
654 && language_mode
== language_mode_auto
)
656 set_language (s
->language
);
661 /* Return the register saved in the simplistic ``saved_regs'' cache.
662 If the value isn't here AND a value is needed, try the next inner
666 legacy_saved_regs_prev_register (struct frame_info
*next_frame
,
667 void **this_prologue_cache
,
668 int regnum
, int *optimizedp
,
669 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
670 int *realnump
, void *bufferp
)
672 /* HACK: New code is passed the next frame and this cache.
673 Unfortunatly, old code expects this frame. Since this is a
674 backward compatibility hack, cheat by walking one level along the
675 prologue chain to the frame the old code expects.
677 Do not try this at home. Professional driver, closed course. */
678 struct frame_info
*frame
= next_frame
->prev
;
679 gdb_assert (frame
!= NULL
);
681 /* Only (older) architectures that implement the
682 DEPRECATED_FRAME_INIT_SAVED_REGS method should be using this
684 gdb_assert (DEPRECATED_FRAME_INIT_SAVED_REGS_P ());
686 /* Load the saved_regs register cache. */
687 if (get_frame_saved_regs (frame
) == NULL
)
688 DEPRECATED_FRAME_INIT_SAVED_REGS (frame
);
690 if (get_frame_saved_regs (frame
) != NULL
691 && get_frame_saved_regs (frame
)[regnum
] != 0)
693 if (regnum
== SP_REGNUM
)
695 /* SP register treated specially. */
701 store_address (bufferp
, REGISTER_RAW_SIZE (regnum
),
702 get_frame_saved_regs (frame
)[regnum
]);
706 /* Any other register is saved in memory, fetch it but cache
707 a local copy of its value. */
709 *lvalp
= lval_memory
;
710 *addrp
= get_frame_saved_regs (frame
)[regnum
];
715 /* Save each register value, as it is read in, in a
716 frame based cache. */
717 void **regs
= (*this_prologue_cache
);
720 int sizeof_cache
= ((NUM_REGS
+ NUM_PSEUDO_REGS
)
722 regs
= frame_obstack_zalloc (sizeof_cache
);
723 (*this_prologue_cache
) = regs
;
725 if (regs
[regnum
] == NULL
)
728 = frame_obstack_zalloc (REGISTER_RAW_SIZE (regnum
));
729 read_memory (get_frame_saved_regs (frame
)[regnum
], regs
[regnum
],
730 REGISTER_RAW_SIZE (regnum
));
732 memcpy (bufferp
, regs
[regnum
], REGISTER_RAW_SIZE (regnum
));
734 /* Read the value in from memory. */
735 read_memory (get_frame_saved_regs (frame
)[regnum
], bufferp
,
736 REGISTER_RAW_SIZE (regnum
));
743 /* No luck. Assume this and the next frame have the same register
744 value. Pass the unwind request down the frame chain to the next
745 frame. Hopefully that frame will find the register's location. */
746 frame_register_unwind (next_frame
, regnum
, optimizedp
, lvalp
, addrp
,
751 legacy_saved_regs_this_id (struct frame_info
*next_frame
,
752 void **this_prologue_cache
,
759 if (frame_relative_level (next_frame
) < 0)
761 /* FIXME: cagney/2003-03-14: We've got the extra special case of
762 unwinding a sentinel frame, the PC of which is pointing at a
763 stack dummy. Fake up the dummy frame's ID using the same
764 sequence as is found a traditional unwinder. */
765 (*id
) = frame_id_build (read_fp (), read_pc ());
769 /* Start out by assuming it's NULL. */
770 (*id
) = null_frame_id
;
772 if (frame_relative_level (next_frame
) <= 0)
773 /* FIXME: 2002-11-09: Frameless functions can occure anywhere in
774 the frame chain, not just the inner most frame! The generic,
775 per-architecture, frame code should handle this and the below
776 should simply be removed. */
777 fromleaf
= FRAMELESS_FUNCTION_INVOCATION (next_frame
);
782 /* A frameless inner-most frame. The `FP' (which isn't an
783 architecture frame-pointer register!) of the caller is the same
785 /* FIXME: 2002-11-09: There isn't any reason to special case this
786 edge condition. Instead the per-architecture code should hande
788 base
= get_frame_base (next_frame
);
791 /* Two macros defined in tm.h specify the machine-dependent
792 actions to be performed here.
794 First, get the frame's chain-pointer.
796 If that is zero, the frame is the outermost frame or a leaf
797 called by the outermost frame. This means that if start
798 calls main without a frame, we'll return 0 (which is fine
801 Nope; there's a problem. This also returns when the current
802 routine is a leaf of main. This is unacceptable. We move
803 this to after the ffi test; I'd rather have backtraces from
804 start go curfluy than have an abort called from main not show
806 gdb_assert (DEPRECATED_FRAME_CHAIN_P ());
807 base
= DEPRECATED_FRAME_CHAIN (next_frame
);
809 if (!frame_chain_valid (base
, next_frame
))
815 /* FIXME: cagney/2002-06-08: This should probably return the frame's
816 function and not the PC (a.k.a. resume address). */
817 pc
= frame_pc_unwind (next_frame
);
818 (*id
) = frame_id_build (base
, pc
);
821 const struct frame_unwind legacy_saved_regs_unwinder
= {
822 /* Not really. It gets overridden by legacy_get_prev_frame. */
824 legacy_saved_regs_this_id
,
825 legacy_saved_regs_prev_register
827 const struct frame_unwind
*legacy_saved_regs_unwind
= &legacy_saved_regs_unwinder
;
830 /* Function: deprecated_generic_get_saved_register
831 Find register number REGNUM relative to FRAME and put its (raw,
832 target format) contents in *RAW_BUFFER.
834 Set *OPTIMIZED if the variable was optimized out (and thus can't be
835 fetched). Note that this is never set to anything other than zero
836 in this implementation.
838 Set *LVAL to lval_memory, lval_register, or not_lval, depending on
839 whether the value was fetched from memory, from a register, or in a
840 strange and non-modifiable way (e.g. a frame pointer which was
841 calculated rather than fetched). We will use not_lval for values
842 fetched from generic dummy frames.
844 Set *ADDRP to the address, either in memory or as a REGISTER_BYTE
845 offset into the registers array. If the value is stored in a dummy
846 frame, set *ADDRP to zero.
848 The argument RAW_BUFFER must point to aligned memory. */
851 deprecated_generic_get_saved_register (char *raw_buffer
, int *optimized
,
853 struct frame_info
*frame
, int regnum
,
854 enum lval_type
*lval
)
856 if (!target_has_registers
)
857 error ("No registers.");
859 gdb_assert (DEPRECATED_FRAME_INIT_SAVED_REGS_P ());
861 /* Normal systems don't optimize out things with register numbers. */
862 if (optimized
!= NULL
)
865 if (addrp
) /* default assumption: not found in memory */
868 /* Note: since the current frame's registers could only have been
869 saved by frames INTERIOR TO the current frame, we skip examining
870 the current frame itself: otherwise, we would be getting the
871 previous frame's registers which were saved by the current frame. */
875 for (frame
= get_next_frame (frame
);
876 frame_relative_level (frame
) >= 0;
877 frame
= get_next_frame (frame
))
879 if (get_frame_type (frame
) == DUMMY_FRAME
)
881 if (lval
) /* found it in a CALL_DUMMY frame */
884 /* FIXME: cagney/2002-06-26: This should be via the
885 gdbarch_register_read() method so that it, on the
886 fly, constructs either a raw or pseudo register
887 from the raw register cache. */
889 (generic_find_dummy_frame (get_frame_pc (frame
),
890 get_frame_base (frame
)),
895 DEPRECATED_FRAME_INIT_SAVED_REGS (frame
);
896 if (get_frame_saved_regs (frame
) != NULL
897 && get_frame_saved_regs (frame
)[regnum
] != 0)
899 if (lval
) /* found it saved on the stack */
901 if (regnum
== SP_REGNUM
)
903 if (raw_buffer
) /* SP register treated specially */
904 store_address (raw_buffer
, REGISTER_RAW_SIZE (regnum
),
905 get_frame_saved_regs (frame
)[regnum
]);
909 if (addrp
) /* any other register */
910 *addrp
= get_frame_saved_regs (frame
)[regnum
];
912 read_memory (get_frame_saved_regs (frame
)[regnum
], raw_buffer
,
913 REGISTER_RAW_SIZE (regnum
));
920 /* If we get thru the loop to this point, it means the register was
921 not saved in any frame. Return the actual live-register value. */
923 if (lval
) /* found it in a live register */
924 *lval
= lval_register
;
926 *addrp
= REGISTER_BYTE (regnum
);
928 deprecated_read_register_gen (regnum
, raw_buffer
);
931 /* Determine the frame's type based on its PC. */
933 static enum frame_type
934 frame_type_from_pc (CORE_ADDR pc
)
936 /* FIXME: cagney/2002-11-24: Can't yet directly call
937 pc_in_dummy_frame() as some architectures don't set
938 PC_IN_CALL_DUMMY() to generic_pc_in_call_dummy() (remember the
939 latter is implemented by simply calling pc_in_dummy_frame). */
940 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
941 && DEPRECATED_PC_IN_CALL_DUMMY (pc
, 0, 0))
946 find_pc_partial_function (pc
, &name
, NULL
, NULL
);
947 if (PC_IN_SIGTRAMP (pc
, name
))
948 return SIGTRAMP_FRAME
;
954 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
955 Always returns a non-NULL value. */
958 create_new_frame (CORE_ADDR addr
, CORE_ADDR pc
)
960 struct frame_info
*fi
;
962 fi
= frame_obstack_zalloc (sizeof (struct frame_info
));
964 fi
->next
= create_sentinel_frame (current_regcache
);
966 /* Select/initialize both the unwind function and the frame's type
968 fi
->unwind
= frame_unwind_find_by_pc (current_gdbarch
, fi
->pc
);
969 if (fi
->unwind
->type
!= UNKNOWN_FRAME
)
970 fi
->type
= fi
->unwind
->type
;
972 fi
->type
= frame_type_from_pc (pc
);
974 deprecated_update_frame_base_hack (fi
, addr
);
975 deprecated_update_frame_pc_hack (fi
, pc
);
977 if (DEPRECATED_INIT_EXTRA_FRAME_INFO_P ())
978 DEPRECATED_INIT_EXTRA_FRAME_INFO (0, fi
);
983 /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the
984 innermost frame). Be careful to not fall off the bottom of the
985 frame chain and onto the sentinel frame. */
988 get_next_frame (struct frame_info
*this_frame
)
990 if (this_frame
->level
> 0)
991 return this_frame
->next
;
996 /* Flush the entire frame cache. */
999 flush_cached_frames (void)
1001 /* Since we can't really be sure what the first object allocated was */
1002 obstack_free (&frame_cache_obstack
, 0);
1003 obstack_init (&frame_cache_obstack
);
1005 current_frame
= NULL
; /* Invalidate cache */
1006 select_frame (NULL
);
1007 annotate_frames_invalid ();
1010 /* Flush the frame cache, and start a new one if necessary. */
1013 reinit_frame_cache (void)
1015 flush_cached_frames ();
1017 /* FIXME: The inferior_ptid test is wrong if there is a corefile. */
1018 if (PIDGET (inferior_ptid
) != 0)
1020 select_frame (get_current_frame ());
1024 /* Create the previous frame using the deprecated methods
1025 INIT_EXTRA_INFO, INIT_FRAME_PC and INIT_FRAME_PC_FIRST. */
1027 static struct frame_info
*
1028 legacy_get_prev_frame (struct frame_info
*this_frame
)
1030 CORE_ADDR address
= 0;
1031 struct frame_info
*prev
;
1034 /* Allocate the new frame but do not wire it in to the frame chain.
1035 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
1036 frame->next to pull some fancy tricks (of course such code is, by
1037 definition, recursive). Try to prevent it.
1039 There is no reason to worry about memory leaks, should the
1040 remainder of the function fail. The allocated memory will be
1041 quickly reclaimed when the frame cache is flushed, and the `we've
1042 been here before' check, in get_prev_frame will stop repeated
1043 memory allocation calls. */
1044 prev
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1045 prev
->level
= this_frame
->level
+ 1;
1047 /* NOTE: cagney/2002-11-18: Should have been correctly setting the
1048 frame's type here, before anything else, and not last, at the
1049 bottom of this function. The various
1050 DEPRECATED_INIT_EXTRA_FRAME_INFO, DEPRECATED_INIT_FRAME_PC,
1051 DEPRECATED_INIT_FRAME_PC_FIRST and
1052 DEPRECATED_FRAME_INIT_SAVED_REGS methods are full of work-arounds
1053 that handle the frame not being correctly set from the start.
1054 Unfortunatly those same work-arounds rely on the type defaulting
1055 to NORMAL_FRAME. Ulgh! The new frame code does not have this
1057 prev
->type
= UNKNOWN_FRAME
;
1059 /* A legacy frame's ID is always computed here. Mark it as valid. */
1062 /* Handle sentinel frame unwind as a special case. */
1063 if (this_frame
->level
< 0)
1065 /* Try to unwind the PC. If that doesn't work, assume we've reached
1066 the oldest frame and simply return. Is there a better sentinal
1067 value? The unwound PC value is then used to initialize the new
1068 previous frame's type.
1070 Note that the pc-unwind is intentionally performed before the
1071 frame chain. This is ok since, for old targets, both
1072 frame_pc_unwind (nee, DEPRECATED_FRAME_SAVED_PC) and
1073 DEPRECATED_FRAME_CHAIN()) assume THIS_FRAME's data structures
1074 have already been initialized (using
1075 DEPRECATED_INIT_EXTRA_FRAME_INFO) and hence the call order
1078 By unwinding the PC first, it becomes possible to, in the case of
1079 a dummy frame, avoid also unwinding the frame ID. This is
1080 because (well ignoring the PPC) a dummy frame can be located
1081 using THIS_FRAME's frame ID. */
1083 deprecated_update_frame_pc_hack (prev
, frame_pc_unwind (this_frame
));
1084 if (get_frame_pc (prev
) == 0)
1086 /* The allocated PREV_FRAME will be reclaimed when the frame
1087 obstack is next purged. */
1089 fprintf_unfiltered (gdb_stdlog
,
1090 "Outermost frame - unwound PC zero\n");
1094 /* Set the unwind functions based on that identified PC. Ditto
1095 for the "type" but strongly prefer the unwinder's frame type. */
1096 prev
->unwind
= frame_unwind_find_by_pc (current_gdbarch
, prev
->pc
);
1097 if (prev
->unwind
->type
== UNKNOWN_FRAME
)
1098 prev
->type
= frame_type_from_pc (prev
->pc
);
1100 prev
->type
= prev
->unwind
->type
;
1102 /* Find the prev's frame's ID. */
1103 if (prev
->type
== DUMMY_FRAME
1104 && gdbarch_unwind_dummy_id_p (current_gdbarch
))
1106 /* When unwinding a normal frame, the stack structure is
1107 determined by analyzing the frame's function's code (be
1108 it using brute force prologue analysis, or the dwarf2
1109 CFI). In the case of a dummy frame, that simply isn't
1110 possible. The The PC is either the program entry point,
1111 or some random address on the stack. Trying to use that
1112 PC to apply standard frame ID unwind techniques is just
1113 asking for trouble. */
1114 /* Assume call_function_by_hand(), via SAVE_DUMMY_FRAME_TOS,
1115 previously saved the dummy frame's ID. Things only work
1116 if the two return the same value. */
1117 gdb_assert (SAVE_DUMMY_FRAME_TOS_P ());
1118 /* Use an architecture specific method to extract the prev's
1119 dummy ID from the next frame. Note that this method uses
1120 frame_register_unwind to obtain the register values
1121 needed to determine the dummy frame's ID. */
1122 prev
->id
= gdbarch_unwind_dummy_id (current_gdbarch
, this_frame
);
1126 /* We're unwinding a sentinel frame, the PC of which is
1127 pointing at a stack dummy. Fake up the dummy frame's ID
1128 using the same sequence as is found a traditional
1129 unwinder. Once all architectures supply the
1130 unwind_dummy_id method, this code can go away. */
1131 prev
->id
= frame_id_build (read_fp (), read_pc ());
1134 /* Check that the unwound ID is valid. */
1135 if (!frame_id_p (prev
->id
))
1138 fprintf_unfiltered (gdb_stdlog
,
1139 "Outermost legacy sentinel frame - unwound frame ID invalid\n");
1143 /* Check that the new frame isn't inner to (younger, below,
1144 next) the old frame. If that happens the frame unwind is
1146 /* FIXME: cagney/2003-02-25: Ignore the sentinel frame since
1147 that doesn't have a valid frame ID. Should instead set the
1148 sentinel frame's frame ID to a `sentinel'. Leave it until
1149 after the switch to storing the frame ID, instead of the
1150 frame base, in the frame object. */
1152 /* FIXME: cagney/2002-12-18: Instead of this hack, should only
1153 store the frame ID in PREV_FRAME. Unfortunatly, some
1154 architectures (HP/UX) still reply on EXTRA_FRAME_INFO and,
1155 hence, still poke at the "struct frame_info" object directly. */
1156 /* FIXME: cagney/2003-04-04: Once ->frame is eliminated, this
1157 assignment can go. */
1158 prev
->frame
= prev
->id
.base
;
1161 this_frame
->prev
= prev
;
1162 prev
->next
= this_frame
;
1164 /* FIXME: cagney/2002-01-19: This call will go away. Instead of
1165 initializing extra info, all frames will use the frame_cache
1166 (passed to the unwind functions) to store additional frame
1167 info. Unfortunatly legacy targets can't use
1168 legacy_get_prev_frame() to unwind the sentinel frame and,
1169 consequently, are forced to take this code path and rely on
1170 the below call to DEPRECATED_INIT_EXTRA_FRAME_INFO to
1171 initialize the inner-most frame. */
1172 if (DEPRECATED_INIT_EXTRA_FRAME_INFO_P ())
1174 DEPRECATED_INIT_EXTRA_FRAME_INFO (0, prev
);
1179 /* This code only works on normal frames. A sentinel frame, where
1180 the level is -1, should never reach this code. */
1181 gdb_assert (this_frame
->level
>= 0);
1183 /* On some machines it is possible to call a function without
1184 setting up a stack frame for it. On these machines, we
1185 define this macro to take two args; a frameinfo pointer
1186 identifying a frame and a variable to set or clear if it is
1187 or isn't leafless. */
1189 /* Still don't want to worry about this except on the innermost
1190 frame. This macro will set FROMLEAF if THIS_FRAME is a frameless
1191 function invocation. */
1192 if (this_frame
->level
== 0)
1193 /* FIXME: 2002-11-09: Frameless functions can occure anywhere in
1194 the frame chain, not just the inner most frame! The generic,
1195 per-architecture, frame code should handle this and the below
1196 should simply be removed. */
1197 fromleaf
= FRAMELESS_FUNCTION_INVOCATION (this_frame
);
1202 /* A frameless inner-most frame. The `FP' (which isn't an
1203 architecture frame-pointer register!) of the caller is the same
1205 /* FIXME: 2002-11-09: There isn't any reason to special case this
1206 edge condition. Instead the per-architecture code should hande
1208 address
= get_frame_base (this_frame
);
1211 /* Two macros defined in tm.h specify the machine-dependent
1212 actions to be performed here.
1214 First, get the frame's chain-pointer.
1216 If that is zero, the frame is the outermost frame or a leaf
1217 called by the outermost frame. This means that if start
1218 calls main without a frame, we'll return 0 (which is fine
1221 Nope; there's a problem. This also returns when the current
1222 routine is a leaf of main. This is unacceptable. We move
1223 this to after the ffi test; I'd rather have backtraces from
1224 start go curfluy than have an abort called from main not show
1226 gdb_assert (DEPRECATED_FRAME_CHAIN_P ());
1227 address
= DEPRECATED_FRAME_CHAIN (this_frame
);
1229 if (!frame_chain_valid (address
, this_frame
))
1235 /* Link in the already allocated prev frame. */
1236 this_frame
->prev
= prev
;
1237 prev
->next
= this_frame
;
1238 deprecated_update_frame_base_hack (prev
, address
);
1240 /* This change should not be needed, FIXME! We should determine
1241 whether any targets *need* DEPRECATED_INIT_FRAME_PC to happen
1242 after DEPRECATED_INIT_EXTRA_FRAME_INFO and come up with a simple
1243 way to express what goes on here.
1245 DEPRECATED_INIT_EXTRA_FRAME_INFO is called from two places:
1246 create_new_frame (where the PC is already set up) and here (where
1247 it isn't). DEPRECATED_INIT_FRAME_PC is only called from here,
1248 always after DEPRECATED_INIT_EXTRA_FRAME_INFO.
1250 The catch is the MIPS, where DEPRECATED_INIT_EXTRA_FRAME_INFO
1251 requires the PC value (which hasn't been set yet). Some other
1252 machines appear to require DEPRECATED_INIT_EXTRA_FRAME_INFO
1253 before they can do DEPRECATED_INIT_FRAME_PC. Phoo.
1255 We shouldn't need DEPRECATED_INIT_FRAME_PC_FIRST to add more
1256 complication to an already overcomplicated part of GDB.
1257 gnu@cygnus.com, 15Sep92.
1259 Assuming that some machines need DEPRECATED_INIT_FRAME_PC after
1260 DEPRECATED_INIT_EXTRA_FRAME_INFO, one possible scheme:
1262 SETUP_INNERMOST_FRAME(): Default version is just create_new_frame
1263 (read_fp ()), read_pc ()). Machines with extra frame info would
1264 do that (or the local equivalent) and then set the extra fields.
1266 SETUP_ARBITRARY_FRAME(argc, argv): Only change here is that
1267 create_new_frame would no longer init extra frame info;
1268 SETUP_ARBITRARY_FRAME would have to do that.
1270 INIT_PREV_FRAME(fromleaf, prev) Replace
1271 DEPRECATED_INIT_EXTRA_FRAME_INFO and DEPRECATED_INIT_FRAME_PC.
1272 This should also return a flag saying whether to keep the new
1273 frame, or whether to discard it, because on some machines (e.g.
1274 mips) it is really awkward to have DEPRECATED_FRAME_CHAIN_VALID
1275 called BEFORE DEPRECATED_INIT_EXTRA_FRAME_INFO (there is no good
1276 way to get information deduced in DEPRECATED_FRAME_CHAIN_VALID
1277 into the extra fields of the new frame). std_frame_pc(fromleaf,
1280 This is the default setting for INIT_PREV_FRAME. It just does
1281 what the default DEPRECATED_INIT_FRAME_PC does. Some machines
1282 will call it from INIT_PREV_FRAME (either at the beginning, the
1283 end, or in the middle). Some machines won't use it.
1285 kingdon@cygnus.com, 13Apr93, 31Jan94, 14Dec94. */
1287 /* NOTE: cagney/2002-11-09: Just ignore the above! There is no
1288 reason for things to be this complicated.
1290 The trick is to assume that there is always a frame. Instead of
1291 special casing the inner-most frame, create fake frame
1292 (containing the hardware registers) that is inner to the
1293 user-visible inner-most frame (...) and then unwind from that.
1294 That way architecture code can use use the standard
1295 frame_XX_unwind() functions and not differentiate between the
1296 inner most and any other case.
1298 Since there is always a frame to unwind from, there is always
1299 somewhere (THIS_FRAME) to store all the info needed to construct
1300 a new (previous) frame without having to first create it. This
1301 means that the convolution below - needing to carefully order a
1302 frame's initialization - isn't needed.
1304 The irony here though, is that DEPRECATED_FRAME_CHAIN(), at least
1305 for a more up-to-date architecture, always calls
1306 FRAME_SAVED_PC(), and FRAME_SAVED_PC() computes the PC but
1307 without first needing the frame! Instead of the convolution
1308 below, we could have simply called FRAME_SAVED_PC() and been done
1309 with it! Note that FRAME_SAVED_PC() is being superseed by
1310 frame_pc_unwind() and that function does have somewhere to cache
1313 if (DEPRECATED_INIT_FRAME_PC_FIRST_P ())
1314 deprecated_update_frame_pc_hack (prev
,
1315 DEPRECATED_INIT_FRAME_PC_FIRST (fromleaf
,
1318 if (DEPRECATED_INIT_EXTRA_FRAME_INFO_P ())
1319 DEPRECATED_INIT_EXTRA_FRAME_INFO (fromleaf
, prev
);
1321 /* This entry is in the frame queue now, which is good since
1322 FRAME_SAVED_PC may use that queue to figure out its value (see
1323 tm-sparc.h). We want the pc saved in the inferior frame. */
1324 if (DEPRECATED_INIT_FRAME_PC_P ())
1325 deprecated_update_frame_pc_hack (prev
,
1326 DEPRECATED_INIT_FRAME_PC (fromleaf
,
1329 /* If ->frame and ->pc are unchanged, we are in the process of
1330 getting ourselves into an infinite backtrace. Some architectures
1331 check this in DEPRECATED_FRAME_CHAIN or thereabouts, but it seems
1332 like there is no reason this can't be an architecture-independent
1334 if (get_frame_base (prev
) == get_frame_base (this_frame
)
1335 && get_frame_pc (prev
) == get_frame_pc (this_frame
))
1337 this_frame
->prev
= NULL
;
1338 obstack_free (&frame_cache_obstack
, prev
);
1342 /* Initialize the code used to unwind the frame PREV based on the PC
1343 (and probably other architectural information). The PC lets you
1344 check things like the debug info at that point (dwarf2cfi?) and
1345 use that to decide how the frame should be unwound. */
1346 prev
->unwind
= frame_unwind_find_by_pc (current_gdbarch
,
1347 get_frame_pc (prev
));
1349 /* If the unwinder provides a frame type, use it. Otherwize
1350 continue on to that heuristic mess. */
1351 if (prev
->unwind
->type
!= UNKNOWN_FRAME
)
1353 prev
->type
= prev
->unwind
->type
;
1357 /* NOTE: cagney/2002-11-18: The code segments, found in
1358 create_new_frame and get_prev_frame(), that initializes the
1359 frames type is subtly different. The latter only updates ->type
1360 when it encounters a SIGTRAMP_FRAME or DUMMY_FRAME. This stops
1361 get_prev_frame() overriding the frame's type when the INIT code
1362 has previously set it. This is really somewhat bogus. The
1363 initialization, as seen in create_new_frame(), should occur
1364 before the INIT function has been called. */
1365 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
1366 && (DEPRECATED_PC_IN_CALL_DUMMY_P ()
1367 ? DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (prev
), 0, 0)
1368 : pc_in_dummy_frame (get_frame_pc (prev
))))
1369 prev
->type
= DUMMY_FRAME
;
1372 /* FIXME: cagney/2002-11-10: This should be moved to before the
1373 INIT code above so that the INIT code knows what the frame's
1374 type is (in fact, for a [generic] dummy-frame, the type can
1375 be set and then the entire initialization can be skipped.
1376 Unforunatly, its the INIT code that sets the PC (Hmm, catch
1379 find_pc_partial_function (get_frame_pc (prev
), &name
, NULL
, NULL
);
1380 if (PC_IN_SIGTRAMP (get_frame_pc (prev
), name
))
1381 prev
->type
= SIGTRAMP_FRAME
;
1382 /* FIXME: cagney/2002-11-11: Leave prev->type alone. Some
1383 architectures are forcing the frame's type in INIT so we
1384 don't want to override it here. Remember, NORMAL_FRAME == 0,
1385 so it all works (just :-/). Once this initialization is
1386 moved to the start of this function, all this nastness will
1393 /* Return a structure containing various interesting information
1394 about the frame that called THIS_FRAME. Returns NULL
1395 if there is no such frame. */
1398 get_prev_frame (struct frame_info
*this_frame
)
1400 struct frame_info
*prev_frame
;
1402 /* Return the inner-most frame, when the caller passes in NULL. */
1403 /* NOTE: cagney/2002-11-09: Not sure how this would happen. The
1404 caller should have previously obtained a valid frame using
1405 get_selected_frame() and then called this code - only possibility
1406 I can think of is code behaving badly.
1408 NOTE: cagney/2003-01-10: Talk about code behaving badly. Check
1409 block_innermost_frame(). It does the sequence: frame = NULL;
1410 while (1) { frame = get_prev_frame (frame); .... }. Ulgh! Why
1411 it couldn't be written better, I don't know.
1413 NOTE: cagney/2003-01-11: I suspect what is happening is
1414 block_innermost_frame() is, when the target has no state
1415 (registers, memory, ...), still calling this function. The
1416 assumption being that this function will return NULL indicating
1417 that a frame isn't possible, rather than checking that the target
1418 has state and then calling get_current_frame() and
1419 get_prev_frame(). This is a guess mind. */
1420 if (this_frame
== NULL
)
1422 /* NOTE: cagney/2002-11-09: There was a code segment here that
1423 would error out when CURRENT_FRAME was NULL. The comment
1424 that went with it made the claim ...
1426 ``This screws value_of_variable, which just wants a nice
1427 clean NULL return from block_innermost_frame if there are no
1428 frames. I don't think I've ever seen this message happen
1429 otherwise. And returning NULL here is a perfectly legitimate
1432 Per the above, this code shouldn't even be called with a NULL
1434 return current_frame
;
1437 /* There is always a frame. If this assertion fails, suspect that
1438 something should be calling get_selected_frame() or
1439 get_current_frame(). */
1440 gdb_assert (this_frame
!= NULL
);
1442 if (this_frame
->level
>= 0
1443 && !backtrace_below_main
1444 && inside_main_func (get_frame_pc (this_frame
)))
1445 /* Don't unwind past main(), bug always unwind the sentinel frame.
1446 Note, this is done _before_ the frame has been marked as
1447 previously unwound. That way if the user later decides to
1448 allow unwinds past main(), that just happens. */
1451 fprintf_unfiltered (gdb_stdlog
,
1452 "Outermost frame - inside main func.\n");
1456 /* Only try to do the unwind once. */
1457 if (this_frame
->prev_p
)
1458 return this_frame
->prev
;
1459 this_frame
->prev_p
= 1;
1462 /* If we're inside the entry file, it isn't valid. Don't apply this
1463 test to a dummy frame - dummy frame PC's typically land in the
1464 entry file. Don't apply this test to the sentinel frame.
1465 Sentinel frames should always be allowed to unwind. */
1466 /* NOTE: drow/2002-12-25: should there be a way to disable this
1467 check? It assumes a single small entry file, and the way some
1468 debug readers (e.g. dbxread) figure out which object is the
1469 entry file is somewhat hokey. */
1470 /* NOTE: cagney/2003-01-10: If there is a way of disabling this test
1471 then it should probably be moved to before the ->prev_p test,
1473 /* NOTE: vinschen/2003-04-01: Disabled. It turns out that the call to
1474 inside_entry_file destroys a meaningful backtrace under some
1475 conditions. E. g. the backtrace tests in the asm-source testcase
1476 are broken for some targets. In this test the functions are all
1477 implemented as part of one file and the testcase is not necessarily
1478 linked with a start file (depending on the target). What happens is,
1479 that the first frame is printed normaly and following frames are
1480 treated as being inside the enttry file then. This way, only the
1481 #0 frame is printed in the backtrace output. */
1482 if (this_frame
->type
!= DUMMY_FRAME
&& this_frame
->level
>= 0
1483 && inside_entry_file (get_frame_pc (this_frame
)))
1486 fprintf_unfiltered (gdb_stdlog
,
1487 "Outermost frame - inside entry file\n");
1492 /* If we're already inside the entry function for the main objfile,
1493 then it isn't valid. Don't apply this test to a dummy frame -
1494 dummy frame PC's typically land in the entry func. Don't apply
1495 this test to the sentinel frame. Sentinel frames should always
1496 be allowed to unwind. */
1497 /* NOTE: cagney/2003-02-25: Don't enable until someone has found
1498 hard evidence that this is needed. */
1500 && this_frame
->type
!= DUMMY_FRAME
&& this_frame
->level
>= 0
1501 && inside_entry_func (get_frame_pc (this_frame
)))
1504 fprintf_unfiltered (gdb_stdlog
,
1505 "Outermost frame - inside entry func\n");
1509 /* If any of the old frame initialization methods are around, use
1510 the legacy get_prev_frame method. */
1511 if (legacy_frame_p (current_gdbarch
))
1513 prev_frame
= legacy_get_prev_frame (this_frame
);
1514 if (frame_debug
&& prev_frame
== NULL
)
1515 fprintf_unfiltered (gdb_stdlog
,
1516 "Outermost frame - legacy_get_prev_frame NULL.\n");
1520 /* Check that this frame's ID was valid. If it wasn't, don't try to
1521 unwind to the prev frame. Be careful to not apply this test to
1522 the sentinel frame. */
1523 if (this_frame
->level
>= 0 && !frame_id_p (get_frame_id (this_frame
)))
1526 fprintf_filtered (gdb_stdlog
,
1527 "Outermost frame - this ID is NULL\n");
1531 /* Check that this frame's ID isn't inner to (younger, below, next)
1532 the next frame. This happens when frame unwind goes backwards.
1533 Since the sentinel frame isn't valid, don't apply this if this
1534 frame is entier the inner-most or sentinel frame. */
1535 if (this_frame
->level
> 0
1536 && frame_id_inner (get_frame_id (this_frame
),
1537 get_frame_id (this_frame
->next
)))
1538 error ("This frame inner-to next frame (corrupt stack?)");
1540 /* Check that this and the next frame are different. If they are
1541 not, there is most likely a stack cycle. As with the inner-than
1542 test, avoid the inner-most and sentinel frames. */
1543 /* FIXME: cagney/2003-03-17: Can't yet enable this this check. The
1544 frame_id_eq() method doesn't yet use function addresses when
1545 comparing frame IDs. */
1547 && this_frame
->level
> 0
1548 && frame_id_eq (get_frame_id (this_frame
),
1549 get_frame_id (this_frame
->next
)))
1550 error ("This frame identical to next frame (corrupt stack?)");
1552 /* Allocate the new frame but do not wire it in to the frame chain.
1553 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
1554 frame->next to pull some fancy tricks (of course such code is, by
1555 definition, recursive). Try to prevent it.
1557 There is no reason to worry about memory leaks, should the
1558 remainder of the function fail. The allocated memory will be
1559 quickly reclaimed when the frame cache is flushed, and the `we've
1560 been here before' check above will stop repeated memory
1561 allocation calls. */
1562 prev_frame
= FRAME_OBSTACK_ZALLOC (struct frame_info
);
1563 prev_frame
->level
= this_frame
->level
+ 1;
1565 /* Try to unwind the PC. If that doesn't work, assume we've reached
1566 the oldest frame and simply return. Is there a better sentinal
1567 value? The unwound PC value is then used to initialize the new
1568 previous frame's type.
1570 Note that the pc-unwind is intentionally performed before the
1571 frame chain. This is ok since, for old targets, both
1572 frame_pc_unwind (nee, FRAME_SAVED_PC) and
1573 DEPRECATED_FRAME_CHAIN()) assume THIS_FRAME's data structures
1574 have already been initialized (using
1575 DEPRECATED_INIT_EXTRA_FRAME_INFO) and hence the call order
1578 By unwinding the PC first, it becomes possible to, in the case of
1579 a dummy frame, avoid also unwinding the frame ID. This is
1580 because (well ignoring the PPC) a dummy frame can be located
1581 using THIS_FRAME's frame ID. */
1583 /* FIXME: cagney/2003-04-04: Once ->pc is eliminated, this
1584 assignment can go away. */
1585 prev_frame
->pc
= frame_pc_unwind (this_frame
);
1586 if (prev_frame
->pc
== 0)
1588 /* The allocated PREV_FRAME will be reclaimed when the frame
1589 obstack is next purged. */
1591 fprintf_unfiltered (gdb_stdlog
,
1592 "Outermost frame - unwound PC zero\n");
1596 /* Set the unwind functions based on that identified PC. */
1597 prev_frame
->unwind
= frame_unwind_find_by_pc (current_gdbarch
,
1600 /* FIXME: cagney/2003-04-02: Rather than storing the frame's type in
1601 the frame, the unwinder's type should be returned directly.
1602 Unfortunatly, legacy code, called by legacy_get_prev_frame,
1603 explicitly set the frames type using the method
1604 deprecated_set_frame_type(). */
1605 gdb_assert (prev_frame
->unwind
->type
!= UNKNOWN_FRAME
);
1606 prev_frame
->type
= prev_frame
->unwind
->type
;
1608 /* Can the frame's type and unwinder be computed on demand? That
1609 would make a frame's creation really really lite! */
1611 /* The prev's frame's ID is computed by demand in get_frame_id(). */
1613 /* The unwound frame ID is validate at the start of this function,
1614 as part of the logic to decide if that frame should be further
1615 unwound, and not here while the prev frame is being created.
1616 Doing this makes it possible for the user to examine a frame that
1617 has an invalid frame ID.
1619 The very old VAX frame_args_address_correct() method noted: [...]
1620 For the sake of argument, suppose that the stack is somewhat
1621 trashed (which is one reason that "info frame" exists). So,
1622 return 0 (indicating we don't know the address of the arglist) if
1623 we don't know what frame this frame calls. */
1626 this_frame
->prev
= prev_frame
;
1627 prev_frame
->next
= this_frame
;
1633 get_frame_pc (struct frame_info
*frame
)
1639 pc_notcurrent (struct frame_info
*frame
)
1641 /* If FRAME is not the innermost frame, that normally means that
1642 FRAME->pc points at the return instruction (which is *after* the
1643 call instruction), and we want to get the line containing the
1644 call (because the call is where the user thinks the program is).
1645 However, if the next frame is either a SIGTRAMP_FRAME or a
1646 DUMMY_FRAME, then the next frame will contain a saved interrupt
1647 PC and such a PC indicates the current (rather than next)
1648 instruction/line, consequently, for such cases, want to get the
1649 line containing fi->pc. */
1650 struct frame_info
*next
= get_next_frame (frame
);
1651 int notcurrent
= (next
!= NULL
&& get_frame_type (next
) == NORMAL_FRAME
);
1656 find_frame_sal (struct frame_info
*frame
, struct symtab_and_line
*sal
)
1658 (*sal
) = find_pc_line (get_frame_pc (frame
), pc_notcurrent (frame
));
1661 /* Per "frame.h", return the ``address'' of the frame. Code should
1662 really be using get_frame_id(). */
1664 get_frame_base (struct frame_info
*fi
)
1668 /* HACK: Force the ID code to (indirectly) initialize the
1675 /* High-level offsets into the frame. Used by the debug info. */
1678 get_frame_base_address (struct frame_info
*fi
)
1680 if (get_frame_type (fi
) != NORMAL_FRAME
)
1682 if (fi
->base
== NULL
)
1683 fi
->base
= frame_base_find_by_pc (current_gdbarch
, get_frame_pc (fi
));
1684 /* Sneaky: If the low-level unwind and high-level base code share a
1685 common unwinder, let them share the prologue cache. */
1686 if (fi
->base
->unwind
== fi
->unwind
)
1687 return fi
->base
->this_base (fi
->next
, &fi
->prologue_cache
);
1688 return fi
->base
->this_base (fi
->next
, &fi
->base_cache
);
1692 get_frame_locals_address (struct frame_info
*fi
)
1695 if (get_frame_type (fi
) != NORMAL_FRAME
)
1697 /* If there isn't a frame address method, find it. */
1698 if (fi
->base
== NULL
)
1699 fi
->base
= frame_base_find_by_pc (current_gdbarch
, get_frame_pc (fi
));
1700 /* Sneaky: If the low-level unwind and high-level base code share a
1701 common unwinder, let them share the prologue cache. */
1702 if (fi
->base
->unwind
== fi
->unwind
)
1703 cache
= &fi
->prologue_cache
;
1705 cache
= &fi
->base_cache
;
1706 return fi
->base
->this_locals (fi
->next
, cache
);
1710 get_frame_args_address (struct frame_info
*fi
)
1713 if (get_frame_type (fi
) != NORMAL_FRAME
)
1715 /* If there isn't a frame address method, find it. */
1716 if (fi
->base
== NULL
)
1717 fi
->base
= frame_base_find_by_pc (current_gdbarch
, get_frame_pc (fi
));
1718 /* Sneaky: If the low-level unwind and high-level base code share a
1719 common unwinder, let them share the prologue cache. */
1720 if (fi
->base
->unwind
== fi
->unwind
)
1721 cache
= &fi
->prologue_cache
;
1723 cache
= &fi
->base_cache
;
1724 return fi
->base
->this_args (fi
->next
, cache
);
1727 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
1728 or -1 for a NULL frame. */
1731 frame_relative_level (struct frame_info
*fi
)
1740 get_frame_type (struct frame_info
*frame
)
1742 /* Some targets still don't use [generic] dummy frames. Catch them
1744 if (!DEPRECATED_USE_GENERIC_DUMMY_FRAMES
1745 && deprecated_frame_in_dummy (frame
))
1747 if (frame
->type
== UNKNOWN_FRAME
)
1748 return NORMAL_FRAME
;
1754 deprecated_set_frame_type (struct frame_info
*frame
, enum frame_type type
)
1756 /* Arrrg! See comment in "frame.h". */
1760 #ifdef FRAME_FIND_SAVED_REGS
1761 /* XXX - deprecated. This is a compatibility function for targets
1762 that do not yet implement DEPRECATED_FRAME_INIT_SAVED_REGS. */
1763 /* Find the addresses in which registers are saved in FRAME. */
1766 deprecated_get_frame_saved_regs (struct frame_info
*frame
,
1767 struct frame_saved_regs
*saved_regs_addr
)
1769 if (frame
->saved_regs
== NULL
)
1771 frame
->saved_regs
= (CORE_ADDR
*)
1772 frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS
);
1774 if (saved_regs_addr
== NULL
)
1776 struct frame_saved_regs saved_regs
;
1777 FRAME_FIND_SAVED_REGS (frame
, saved_regs
);
1778 memcpy (frame
->saved_regs
, &saved_regs
, SIZEOF_FRAME_SAVED_REGS
);
1782 FRAME_FIND_SAVED_REGS (frame
, *saved_regs_addr
);
1783 memcpy (frame
->saved_regs
, saved_regs_addr
, SIZEOF_FRAME_SAVED_REGS
);
1788 struct frame_extra_info
*
1789 get_frame_extra_info (struct frame_info
*fi
)
1791 return fi
->extra_info
;
1794 struct frame_extra_info
*
1795 frame_extra_info_zalloc (struct frame_info
*fi
, long size
)
1797 fi
->extra_info
= frame_obstack_zalloc (size
);
1798 return fi
->extra_info
;
1802 deprecated_update_frame_pc_hack (struct frame_info
*frame
, CORE_ADDR pc
)
1804 /* See comment in "frame.h". */
1806 /* NOTE: cagney/2003-03-11: Some architectures (e.g., Arm) are
1807 maintaining a locally allocated frame object. Since such frame's
1808 are not in the frame chain, it isn't possible to assume that the
1809 frame has a next. Sigh. */
1810 if (frame
->next
!= NULL
)
1812 /* While we're at it, update this frame's cached PC value, found
1813 in the next frame. Oh for the day when "struct frame_info"
1814 is opaque and this hack on hack can just go away. */
1815 frame
->next
->pc_unwind_cache
= pc
;
1816 frame
->next
->pc_unwind_cache_p
= 1;
1821 deprecated_update_frame_base_hack (struct frame_info
*frame
, CORE_ADDR base
)
1823 /* See comment in "frame.h". */
1824 frame
->frame
= base
;
1828 deprecated_set_frame_saved_regs_hack (struct frame_info
*frame
,
1829 CORE_ADDR
*saved_regs
)
1831 frame
->saved_regs
= saved_regs
;
1835 deprecated_set_frame_extra_info_hack (struct frame_info
*frame
,
1836 struct frame_extra_info
*extra_info
)
1838 frame
->extra_info
= extra_info
;
1842 deprecated_set_frame_next_hack (struct frame_info
*fi
,
1843 struct frame_info
*next
)
1849 deprecated_set_frame_prev_hack (struct frame_info
*fi
,
1850 struct frame_info
*prev
)
1856 deprecated_get_frame_context (struct frame_info
*fi
)
1862 deprecated_set_frame_context (struct frame_info
*fi
,
1863 struct context
*context
)
1865 fi
->context
= context
;
1869 deprecated_frame_xmalloc (void)
1871 struct frame_info
*frame
= XMALLOC (struct frame_info
);
1872 memset (frame
, 0, sizeof (struct frame_info
));
1877 deprecated_frame_xmalloc_with_cleanup (long sizeof_saved_regs
,
1878 long sizeof_extra_info
)
1880 struct frame_info
*frame
= deprecated_frame_xmalloc ();
1881 make_cleanup (xfree
, frame
);
1882 if (sizeof_saved_regs
> 0)
1884 frame
->saved_regs
= xcalloc (1, sizeof_saved_regs
);
1885 make_cleanup (xfree
, frame
->saved_regs
);
1887 if (sizeof_extra_info
> 0)
1889 frame
->extra_info
= xcalloc (1, sizeof_extra_info
);
1890 make_cleanup (xfree
, frame
->extra_info
);
1896 legacy_frame_p (struct gdbarch
*current_gdbarch
)
1898 return (DEPRECATED_INIT_FRAME_PC_P ()
1899 || DEPRECATED_INIT_FRAME_PC_FIRST_P ()
1900 || DEPRECATED_INIT_EXTRA_FRAME_INFO_P ()
1901 || DEPRECATED_FRAME_CHAIN_P ()
1902 || !gdbarch_unwind_dummy_id_p (current_gdbarch
)
1903 || !SAVE_DUMMY_FRAME_TOS_P ());
1907 _initialize_frame (void)
1909 obstack_init (&frame_cache_obstack
);
1911 /* FIXME: cagney/2003-01-19: This command needs a rename. Suggest
1912 `set backtrace {past,beyond,...}-main'. Also suggest adding `set
1913 backtrace ...-start' to control backtraces past start. The
1914 problem with `below' is that it stops the `up' command. */
1916 add_setshow_boolean_cmd ("backtrace-below-main", class_obscure
,
1917 &backtrace_below_main
, "\
1918 Set whether backtraces should continue past \"main\".\n\
1919 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
1920 the backtrace at \"main\". Set this variable if you need to see the rest\n\
1921 of the stack trace.", "\
1922 Show whether backtraces should continue past \"main\".\n\
1923 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
1924 the backtrace at \"main\". Set this variable if you need to see the rest\n\
1925 of the stack trace.",
1926 NULL
, NULL
, &setlist
, &showlist
);
1929 /* Debug this files internals. */
1930 add_show_from_set (add_set_cmd ("frame", class_maintenance
, var_zinteger
,
1931 &frame_debug
, "Set frame debugging.\n\
1932 When non-zero, frame specific internal debugging is enabled.", &setdebuglist
),