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"
42 /* Flag to indicate whether backtraces should stop at main. */
44 static int backtrace_below_main;
46 /* Return a frame uniq ID that can be used to, later, re-find the
50 get_frame_id (struct frame_info *fi)
65 const struct frame_id null_frame_id; /* All zeros. */
68 frame_id_build (CORE_ADDR base, CORE_ADDR func_or_pc)
77 frame_id_p (struct frame_id l)
79 /* The .func can be NULL but the .base cannot. */
84 frame_id_eq (struct frame_id l, struct frame_id r)
86 /* If .base is different, the frames are different. */
89 /* Add a test to check that the frame ID's are for the same function
95 frame_id_inner (struct frame_id l, struct frame_id r)
97 /* Only return non-zero when strictly inner than. Note that, per
98 comment in "frame.h", there is some fuzz here. Frameless
99 functions are not strictly inner than (same .base but different
101 return INNER_THAN (l.base, r.base);
105 frame_find_by_id (struct frame_id id)
107 struct frame_info *frame;
109 /* ZERO denotes the null frame, let the caller decide what to do
110 about it. Should it instead return get_current_frame()? */
111 if (!frame_id_p (id))
114 for (frame = get_current_frame ();
116 frame = get_prev_frame (frame))
118 struct frame_id this = get_frame_id (frame);
119 if (frame_id_eq (id, this))
120 /* An exact match. */
122 if (frame_id_inner (id, this))
125 /* Either, we're not yet gone far enough out along the frame
126 chain (inner(this,id), or we're comparing frameless functions
127 (same .base, different .func, no test available). Struggle
128 on until we've definitly gone to far. */
134 frame_pc_unwind (struct frame_info *frame)
136 if (!frame->pc_unwind_cache_p)
138 frame->pc_unwind_cache = frame->unwind->pc (frame, &frame->unwind_cache);
139 frame->pc_unwind_cache_p = 1;
141 return frame->pc_unwind_cache;
145 frame_id_unwind (struct frame_info *frame)
147 if (!frame->id_unwind_cache_p)
149 frame->unwind->id (frame, &frame->unwind_cache, &frame->id_unwind_cache);
150 frame->id_unwind_cache_p = 1;
152 return frame->id_unwind_cache;
156 frame_pop (struct frame_info *frame)
158 /* FIXME: cagney/2003-01-18: There is probably a chicken-egg problem
159 with passing in current_regcache. The pop function needs to be
160 written carefully so as to not overwrite registers whose [old]
161 values are needed to restore other registers. Instead, this code
162 should pass in a scratch cache and, as a second step, restore the
163 registers using that. */
164 frame->unwind->pop (frame, &frame->unwind_cache, current_regcache);
165 flush_cached_frames ();
169 frame_register_unwind (struct frame_info *frame, int regnum,
170 int *optimizedp, enum lval_type *lvalp,
171 CORE_ADDR *addrp, int *realnump, void *bufferp)
173 struct frame_unwind_cache *cache;
175 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
176 that the value proper does not need to be fetched. */
177 gdb_assert (optimizedp != NULL);
178 gdb_assert (lvalp != NULL);
179 gdb_assert (addrp != NULL);
180 gdb_assert (realnump != NULL);
181 /* gdb_assert (bufferp != NULL); */
183 /* NOTE: cagney/2002-11-27: A program trying to unwind a NULL frame
184 is broken. There is always a frame. If there, for some reason,
185 isn't, there is some pretty busted code as it should have
186 detected the problem before calling here. */
187 gdb_assert (frame != NULL);
189 /* Ask this frame to unwind its register. */
190 frame->unwind->reg (frame, &frame->unwind_cache, regnum,
191 optimizedp, lvalp, addrp, realnump, bufferp);
195 frame_register (struct frame_info *frame, int regnum,
196 int *optimizedp, enum lval_type *lvalp,
197 CORE_ADDR *addrp, int *realnump, void *bufferp)
199 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
200 that the value proper does not need to be fetched. */
201 gdb_assert (optimizedp != NULL);
202 gdb_assert (lvalp != NULL);
203 gdb_assert (addrp != NULL);
204 gdb_assert (realnump != NULL);
205 /* gdb_assert (bufferp != NULL); */
207 /* Ulgh! Old code that, for lval_register, sets ADDRP to the offset
208 of the register in the register cache. It should instead return
209 the REGNUM corresponding to that register. Translate the . */
210 if (GET_SAVED_REGISTER_P ())
212 GET_SAVED_REGISTER (bufferp, optimizedp, addrp, frame, regnum, lvalp);
213 /* Compute the REALNUM if the caller wants it. */
214 if (*lvalp == lval_register)
217 for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++)
219 if (*addrp == register_offset_hack (current_gdbarch, regnum))
225 internal_error (__FILE__, __LINE__,
226 "Failed to compute the register number corresponding"
227 " to 0x%s", paddr_d (*addrp));
233 /* Obtain the register value by unwinding the register from the next
234 (more inner frame). */
235 gdb_assert (frame != NULL && frame->next != NULL);
236 frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
241 frame_unwind_signed_register (struct frame_info *frame, int regnum,
248 void *buf = alloca (MAX_REGISTER_RAW_SIZE);
249 frame_register_unwind (frame, regnum, &optimized, &lval, &addr,
251 (*val) = extract_signed_integer (buf, REGISTER_VIRTUAL_SIZE (regnum));
255 frame_unwind_unsigned_register (struct frame_info *frame, int regnum,
262 void *buf = alloca (MAX_REGISTER_RAW_SIZE);
263 frame_register_unwind (frame, regnum, &optimized, &lval, &addr,
265 (*val) = extract_unsigned_integer (buf, REGISTER_VIRTUAL_SIZE (regnum));
269 frame_read_unsigned_register (struct frame_info *frame, int regnum,
272 /* NOTE: cagney/2002-10-31: There is a bit of dogma here - there is
273 always a frame. Both this, and the equivalent
274 frame_read_signed_register() function, can only be called with a
275 valid frame. If, for some reason, this function is called
276 without a frame then the problem isn't here, but rather in the
277 caller. It should of first created a frame and then passed that
279 /* NOTE: cagney/2002-10-31: As a side bar, keep in mind that the
280 ``current_frame'' should not be treated as a special case. While
281 ``get_next_frame (current_frame) == NULL'' currently holds, it
282 should, as far as possible, not be relied upon. In the future,
283 ``get_next_frame (current_frame)'' may instead simply return a
284 normal frame object that simply always gets register values from
285 the register cache. Consequently, frame code should try to avoid
286 tests like ``if get_next_frame() == NULL'' and instead just rely
287 on recursive frame calls (like the below code) when manipulating
289 gdb_assert (frame != NULL && frame->next != NULL);
290 frame_unwind_unsigned_register (frame->next, regnum, val);
294 frame_read_signed_register (struct frame_info *frame, int regnum,
297 /* See note above in frame_read_unsigned_register(). */
298 gdb_assert (frame != NULL && frame->next != NULL);
299 frame_unwind_signed_register (frame->next, regnum, val);
303 generic_unwind_get_saved_register (char *raw_buffer,
306 struct frame_info *frame,
308 enum lval_type *lvalp)
313 enum lval_type lvalx;
315 if (!target_has_registers)
316 error ("No registers.");
318 /* Keep things simple, ensure that all the pointers (except valuep)
320 if (optimizedp == NULL)
321 optimizedp = &optimizedx;
327 gdb_assert (frame != NULL && frame->next != NULL);
328 frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
329 &realnumx, raw_buffer);
333 get_saved_register (char *raw_buffer,
336 struct frame_info *frame,
338 enum lval_type *lval)
340 if (GET_SAVED_REGISTER_P ())
342 GET_SAVED_REGISTER (raw_buffer, optimized, addrp, frame, regnum, lval);
345 generic_unwind_get_saved_register (raw_buffer, optimized, addrp, frame,
349 /* frame_register_read ()
351 Find and return the value of REGNUM for the specified stack frame.
352 The number of bytes copied is REGISTER_RAW_SIZE (REGNUM).
354 Returns 0 if the register value could not be found. */
357 frame_register_read (struct frame_info *frame, int regnum, void *myaddr)
363 frame_register (frame, regnum, &optimized, &lval, &addr, &realnum, myaddr);
365 /* FIXME: cagney/2002-05-15: This test, is just bogus.
367 It indicates that the target failed to supply a value for a
368 register because it was "not available" at this time. Problem
369 is, the target still has the register and so get saved_register()
370 may be returning a value saved on the stack. */
372 if (register_cached (regnum) < 0)
373 return 0; /* register value not available */
379 /* Map between a frame register number and its name. A frame register
380 space is a superset of the cooked register space --- it also
381 includes builtin registers. */
384 frame_map_name_to_regnum (const char *name, int len)
388 /* Search register name space. */
389 for (i = 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++)
390 if (REGISTER_NAME (i) && len == strlen (REGISTER_NAME (i))
391 && strncmp (name, REGISTER_NAME (i), len) == 0)
396 /* Try builtin registers. */
397 i = builtin_reg_map_name_to_regnum (name, len);
400 /* A builtin register doesn't fall into the architecture's
402 gdb_assert (i >= NUM_REGS + NUM_PSEUDO_REGS);
410 frame_map_regnum_to_name (int regnum)
414 if (regnum < NUM_REGS + NUM_PSEUDO_REGS)
415 return REGISTER_NAME (regnum);
416 return builtin_reg_map_regnum_to_name (regnum);
419 /* Create a sentinel frame. */
422 create_sentinel_frame (struct regcache *regcache)
424 struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
425 frame->type = NORMAL_FRAME;
427 /* Explicitly initialize the sentinel frame's cache. Provide it
428 with the underlying regcache. In the future additional
429 information, such as the frame's thread will be added. */
430 frame->unwind_cache = sentinel_frame_cache (regcache);
431 /* For the moment there is only one sentinel frame implementation. */
432 frame->unwind = sentinel_frame_unwind;
433 /* Link this frame back to itself. The frame is self referential
434 (the unwound PC is the same as the pc), so make it so. */
436 /* Always unwind the PC as part of creating this frame. This
437 ensures that the frame's PC points at something valid. */
438 /* FIXME: cagney/2003-01-10: Problem here. Unwinding a sentinel
439 frame's PC may require information such as the frame's thread's
440 stop reason. Is it possible to get to that? */
441 frame->pc = frame_pc_unwind (frame);
445 /* Info about the innermost stack frame (contents of FP register) */
447 static struct frame_info *current_frame;
449 /* Cache for frame addresses already read by gdb. Valid only while
450 inferior is stopped. Control variables for the frame cache should
451 be local to this module. */
453 static struct obstack frame_cache_obstack;
456 frame_obstack_zalloc (unsigned long size)
458 void *data = obstack_alloc (&frame_cache_obstack, size);
459 memset (data, 0, size);
464 frame_saved_regs_zalloc (struct frame_info *fi)
466 fi->saved_regs = (CORE_ADDR *)
467 frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS);
468 return fi->saved_regs;
472 get_frame_saved_regs (struct frame_info *fi)
474 return fi->saved_regs;
477 /* Return the innermost (currently executing) stack frame. This is
478 split into two functions. The function unwind_to_current_frame()
479 is wrapped in catch exceptions so that, even when the unwind of the
480 sentinel frame fails, the function still returns a stack frame. */
483 unwind_to_current_frame (struct ui_out *ui_out, void *args)
485 struct frame_info *frame = get_prev_frame (args);
486 /* A sentinel frame can fail to unwind, eg, because it's PC value
487 lands in somewhere like start. */
490 current_frame = frame;
495 get_current_frame (void)
497 if (!target_has_stack)
499 if (!target_has_registers)
500 error ("No registers.");
501 if (!target_has_memory)
502 error ("No memory.");
503 if (current_frame == NULL)
505 struct frame_info *sentinel_frame =
506 create_sentinel_frame (current_regcache);
507 if (catch_exceptions (uiout, unwind_to_current_frame, sentinel_frame,
508 NULL, RETURN_MASK_ERROR) != 0)
510 /* Oops! Fake a current frame? Is this useful? It has a PC
511 of zero, for instance. */
512 current_frame = sentinel_frame;
515 return current_frame;
518 /* The "selected" stack frame is used by default for local and arg
519 access. May be zero, for no selected frame. */
521 struct frame_info *deprecated_selected_frame;
523 /* Return the selected frame. Always non-null (unless there isn't an
524 inferior sufficient for creating a frame) in which case an error is
528 get_selected_frame (void)
530 if (deprecated_selected_frame == NULL)
531 /* Hey! Don't trust this. It should really be re-finding the
532 last selected frame of the currently selected thread. This,
533 though, is better than nothing. */
534 select_frame (get_current_frame ());
535 /* There is always a frame. */
536 gdb_assert (deprecated_selected_frame != NULL);
537 return deprecated_selected_frame;
540 /* Select frame FI (or NULL - to invalidate the current frame). */
543 select_frame (struct frame_info *fi)
545 register struct symtab *s;
547 deprecated_selected_frame = fi;
548 /* NOTE: cagney/2002-05-04: FI can be NULL. This occures when the
549 frame is being invalidated. */
550 if (selected_frame_level_changed_hook)
551 selected_frame_level_changed_hook (frame_relative_level (fi));
553 /* FIXME: kseitz/2002-08-28: It would be nice to call
554 selected_frame_level_changed_event right here, but due to limitations
555 in the current interfaces, we would end up flooding UIs with events
556 because select_frame is used extensively internally.
558 Once we have frame-parameterized frame (and frame-related) commands,
559 the event notification can be moved here, since this function will only
560 be called when the users selected frame is being changed. */
562 /* Ensure that symbols for this frame are read in. Also, determine the
563 source language of this frame, and switch to it if desired. */
566 s = find_pc_symtab (fi->pc);
568 && s->language != current_language->la_language
569 && s->language != language_unknown
570 && language_mode == language_mode_auto)
572 set_language (s->language);
577 /* Return the register saved in the simplistic ``saved_regs'' cache.
578 If the value isn't here AND a value is needed, try the next inner
582 frame_saved_regs_register_unwind (struct frame_info *frame, void **cache,
583 int regnum, int *optimizedp,
584 enum lval_type *lvalp, CORE_ADDR *addrp,
585 int *realnump, void *bufferp)
587 /* There is always a frame at this point. And THIS is the frame
588 we're interested in. */
589 gdb_assert (frame != NULL);
590 /* If we're using generic dummy frames, we'd better not be in a call
591 dummy. (generic_call_dummy_register_unwind ought to have been called
593 gdb_assert (!(DEPRECATED_USE_GENERIC_DUMMY_FRAMES
594 && (get_frame_type (frame) == DUMMY_FRAME)));
596 /* Only (older) architectures that implement the
597 FRAME_INIT_SAVED_REGS method should be using this function. */
598 gdb_assert (FRAME_INIT_SAVED_REGS_P ());
600 /* Load the saved_regs register cache. */
601 if (get_frame_saved_regs (frame) == NULL)
602 FRAME_INIT_SAVED_REGS (frame);
604 if (get_frame_saved_regs (frame) != NULL
605 && get_frame_saved_regs (frame)[regnum] != 0)
607 if (regnum == SP_REGNUM)
609 /* SP register treated specially. */
615 store_address (bufferp, REGISTER_RAW_SIZE (regnum),
616 get_frame_saved_regs (frame)[regnum]);
620 /* Any other register is saved in memory, fetch it but cache
621 a local copy of its value. */
623 *lvalp = lval_memory;
624 *addrp = get_frame_saved_regs (frame)[regnum];
629 /* Save each register value, as it is read in, in a
630 frame based cache. */
631 void **regs = (*cache);
634 int sizeof_cache = ((NUM_REGS + NUM_PSEUDO_REGS)
636 regs = frame_obstack_zalloc (sizeof_cache);
639 if (regs[regnum] == NULL)
642 = frame_obstack_zalloc (REGISTER_RAW_SIZE (regnum));
643 read_memory (get_frame_saved_regs (frame)[regnum], regs[regnum],
644 REGISTER_RAW_SIZE (regnum));
646 memcpy (bufferp, regs[regnum], REGISTER_RAW_SIZE (regnum));
648 /* Read the value in from memory. */
649 read_memory (get_frame_saved_regs (frame)[regnum], bufferp,
650 REGISTER_RAW_SIZE (regnum));
657 /* No luck, assume this and the next frame have the same register
658 value. Pass the request down the frame chain to the next frame.
659 Hopefully that will find the register's location, either in a
660 register or in memory. */
661 frame_register (frame, regnum, optimizedp, lvalp, addrp, realnump,
666 frame_saved_regs_pc_unwind (struct frame_info *frame, void **cache)
668 gdb_assert (FRAME_SAVED_PC_P ());
669 return FRAME_SAVED_PC (frame);
673 frame_saved_regs_id_unwind (struct frame_info *next_frame, void **cache,
680 /* Start out by assuming it's NULL. */
681 (*id) = null_frame_id;
683 if (frame_relative_level (next_frame) <= 0)
684 /* FIXME: 2002-11-09: Frameless functions can occure anywhere in
685 the frame chain, not just the inner most frame! The generic,
686 per-architecture, frame code should handle this and the below
687 should simply be removed. */
688 fromleaf = FRAMELESS_FUNCTION_INVOCATION (next_frame);
693 /* A frameless inner-most frame. The `FP' (which isn't an
694 architecture frame-pointer register!) of the caller is the same
696 /* FIXME: 2002-11-09: There isn't any reason to special case this
697 edge condition. Instead the per-architecture code should hande
699 base = get_frame_base (next_frame);
702 /* Two macros defined in tm.h specify the machine-dependent
703 actions to be performed here.
705 First, get the frame's chain-pointer.
707 If that is zero, the frame is the outermost frame or a leaf
708 called by the outermost frame. This means that if start
709 calls main without a frame, we'll return 0 (which is fine
712 Nope; there's a problem. This also returns when the current
713 routine is a leaf of main. This is unacceptable. We move
714 this to after the ffi test; I'd rather have backtraces from
715 start go curfluy than have an abort called from main not show
717 gdb_assert (FRAME_CHAIN_P ());
718 base = FRAME_CHAIN (next_frame);
720 if (!frame_chain_valid (base, next_frame))
726 /* FIXME: cagney/2002-06-08: This should probably return the frame's
727 function and not the PC (a.k.a. resume address). */
728 pc = frame_pc_unwind (next_frame);
734 frame_saved_regs_pop (struct frame_info *fi, void **cache,
735 struct regcache *regcache)
737 gdb_assert (POP_FRAME_P ());
741 const struct frame_unwind trad_frame_unwinder = {
742 frame_saved_regs_pop,
743 frame_saved_regs_pc_unwind,
744 frame_saved_regs_id_unwind,
745 frame_saved_regs_register_unwind
747 const struct frame_unwind *trad_frame_unwind = &trad_frame_unwinder;
750 /* Function: get_saved_register
751 Find register number REGNUM relative to FRAME and put its (raw,
752 target format) contents in *RAW_BUFFER.
754 Set *OPTIMIZED if the variable was optimized out (and thus can't be
755 fetched). Note that this is never set to anything other than zero
756 in this implementation.
758 Set *LVAL to lval_memory, lval_register, or not_lval, depending on
759 whether the value was fetched from memory, from a register, or in a
760 strange and non-modifiable way (e.g. a frame pointer which was
761 calculated rather than fetched). We will use not_lval for values
762 fetched from generic dummy frames.
764 Set *ADDRP to the address, either in memory or as a REGISTER_BYTE
765 offset into the registers array. If the value is stored in a dummy
766 frame, set *ADDRP to zero.
768 To use this implementation, define a function called
769 "get_saved_register" in your target code, which simply passes all
770 of its arguments to this function.
772 The argument RAW_BUFFER must point to aligned memory. */
775 deprecated_generic_get_saved_register (char *raw_buffer, int *optimized,
777 struct frame_info *frame, int regnum,
778 enum lval_type *lval)
780 if (!target_has_registers)
781 error ("No registers.");
783 gdb_assert (FRAME_INIT_SAVED_REGS_P ());
785 /* Normal systems don't optimize out things with register numbers. */
786 if (optimized != NULL)
789 if (addrp) /* default assumption: not found in memory */
792 /* Note: since the current frame's registers could only have been
793 saved by frames INTERIOR TO the current frame, we skip examining
794 the current frame itself: otherwise, we would be getting the
795 previous frame's registers which were saved by the current frame. */
799 for (frame = get_next_frame (frame);
800 frame_relative_level (frame) >= 0;
801 frame = get_next_frame (frame))
803 if (get_frame_type (frame) == DUMMY_FRAME)
805 if (lval) /* found it in a CALL_DUMMY frame */
808 /* FIXME: cagney/2002-06-26: This should be via the
809 gdbarch_register_read() method so that it, on the
810 fly, constructs either a raw or pseudo register
811 from the raw register cache. */
813 (generic_find_dummy_frame (get_frame_pc (frame),
814 get_frame_base (frame)),
819 FRAME_INIT_SAVED_REGS (frame);
820 if (get_frame_saved_regs (frame) != NULL
821 && get_frame_saved_regs (frame)[regnum] != 0)
823 if (lval) /* found it saved on the stack */
825 if (regnum == SP_REGNUM)
827 if (raw_buffer) /* SP register treated specially */
828 store_address (raw_buffer, REGISTER_RAW_SIZE (regnum),
829 get_frame_saved_regs (frame)[regnum]);
833 if (addrp) /* any other register */
834 *addrp = get_frame_saved_regs (frame)[regnum];
836 read_memory (get_frame_saved_regs (frame)[regnum], raw_buffer,
837 REGISTER_RAW_SIZE (regnum));
844 /* If we get thru the loop to this point, it means the register was
845 not saved in any frame. Return the actual live-register value. */
847 if (lval) /* found it in a live register */
848 *lval = lval_register;
850 *addrp = REGISTER_BYTE (regnum);
852 deprecated_read_register_gen (regnum, raw_buffer);
855 /* Determine the frame's type based on its PC. */
857 static enum frame_type
858 frame_type_from_pc (CORE_ADDR pc)
860 /* FIXME: cagney/2002-11-24: Can't yet directly call
861 pc_in_dummy_frame() as some architectures don't set
862 PC_IN_CALL_DUMMY() to generic_pc_in_call_dummy() (remember the
863 latter is implemented by simply calling pc_in_dummy_frame). */
864 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
865 && DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0))
870 find_pc_partial_function (pc, &name, NULL, NULL);
871 if (PC_IN_SIGTRAMP (pc, name))
872 return SIGTRAMP_FRAME;
878 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
879 Always returns a non-NULL value. */
882 create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
884 struct frame_info *fi;
886 fi = frame_obstack_zalloc (sizeof (struct frame_info));
890 fi->next = create_sentinel_frame (current_regcache);
891 fi->type = frame_type_from_pc (pc);
893 if (INIT_EXTRA_FRAME_INFO_P ())
894 INIT_EXTRA_FRAME_INFO (0, fi);
896 /* Select/initialize an unwind function. */
897 fi->unwind = frame_unwind_find_by_pc (current_gdbarch, fi->pc);
902 /* Return the frame that FRAME calls (NULL if FRAME is the innermost
903 frame). Be careful to not fall off the bottom of the frame chain
904 and onto the sentinel frame. */
907 get_next_frame (struct frame_info *frame)
909 if (frame->level > 0)
915 /* Flush the entire frame cache. */
918 flush_cached_frames (void)
920 /* Since we can't really be sure what the first object allocated was */
921 obstack_free (&frame_cache_obstack, 0);
922 obstack_init (&frame_cache_obstack);
924 current_frame = NULL; /* Invalidate cache */
926 annotate_frames_invalid ();
929 /* Flush the frame cache, and start a new one if necessary. */
932 reinit_frame_cache (void)
934 flush_cached_frames ();
936 /* FIXME: The inferior_ptid test is wrong if there is a corefile. */
937 if (PIDGET (inferior_ptid) != 0)
939 select_frame (get_current_frame ());
943 /* Create the previous frame using the deprecated methods
944 INIT_EXTRA_INFO, INIT_FRAME_PC and INIT_FRAME_PC_FIRST. */
946 static struct frame_info *
947 legacy_get_prev_frame (struct frame_info *next_frame)
949 CORE_ADDR address = 0;
950 struct frame_info *prev;
953 /* This code only works on normal frames. A sentinel frame, where
954 the level is -1, should never reach this code. */
955 gdb_assert (next_frame->level >= 0);
957 /* On some machines it is possible to call a function without
958 setting up a stack frame for it. On these machines, we
959 define this macro to take two args; a frameinfo pointer
960 identifying a frame and a variable to set or clear if it is
961 or isn't leafless. */
963 /* Still don't want to worry about this except on the innermost
964 frame. This macro will set FROMLEAF if NEXT_FRAME is a frameless
965 function invocation. */
966 if (next_frame->level == 0)
967 /* FIXME: 2002-11-09: Frameless functions can occure anywhere in
968 the frame chain, not just the inner most frame! The generic,
969 per-architecture, frame code should handle this and the below
970 should simply be removed. */
971 fromleaf = FRAMELESS_FUNCTION_INVOCATION (next_frame);
976 /* A frameless inner-most frame. The `FP' (which isn't an
977 architecture frame-pointer register!) of the caller is the same
979 /* FIXME: 2002-11-09: There isn't any reason to special case this
980 edge condition. Instead the per-architecture code should hande
982 address = get_frame_base (next_frame);
985 /* Two macros defined in tm.h specify the machine-dependent
986 actions to be performed here.
988 First, get the frame's chain-pointer.
990 If that is zero, the frame is the outermost frame or a leaf
991 called by the outermost frame. This means that if start
992 calls main without a frame, we'll return 0 (which is fine
995 Nope; there's a problem. This also returns when the current
996 routine is a leaf of main. This is unacceptable. We move
997 this to after the ffi test; I'd rather have backtraces from
998 start go curfluy than have an abort called from main not show
1000 gdb_assert (FRAME_CHAIN_P ());
1001 address = FRAME_CHAIN (next_frame);
1003 if (!frame_chain_valid (address, next_frame))
1009 /* Create an initially zero previous frame. */
1010 prev = frame_obstack_zalloc (sizeof (struct frame_info));
1013 next_frame->prev = prev;
1014 prev->next = next_frame;
1015 prev->frame = address;
1016 prev->level = next_frame->level + 1;
1017 /* FIXME: cagney/2002-11-18: Should be setting the frame's type
1018 here, before anything else, and not last. Various INIT functions
1019 are full of work-arounds for the frames type not being set
1020 correctly from the word go. Ulgh! */
1021 prev->type = NORMAL_FRAME;
1023 /* This change should not be needed, FIXME! We should determine
1024 whether any targets *need* DEPRECATED_INIT_FRAME_PC to happen
1025 after INIT_EXTRA_FRAME_INFO and come up with a simple way to
1026 express what goes on here.
1028 INIT_EXTRA_FRAME_INFO is called from two places: create_new_frame
1029 (where the PC is already set up) and here (where it isn't).
1030 DEPRECATED_INIT_FRAME_PC is only called from here, always after
1031 INIT_EXTRA_FRAME_INFO.
1033 The catch is the MIPS, where INIT_EXTRA_FRAME_INFO requires the
1034 PC value (which hasn't been set yet). Some other machines appear
1035 to require INIT_EXTRA_FRAME_INFO before they can do
1036 DEPRECATED_INIT_FRAME_PC. Phoo.
1038 We shouldn't need DEPRECATED_INIT_FRAME_PC_FIRST to add more
1039 complication to an already overcomplicated part of GDB.
1042 Assuming that some machines need DEPRECATED_INIT_FRAME_PC after
1043 INIT_EXTRA_FRAME_INFO, one possible scheme:
1045 SETUP_INNERMOST_FRAME(): Default version is just create_new_frame
1046 (read_fp ()), read_pc ()). Machines with extra frame info would
1047 do that (or the local equivalent) and then set the extra fields.
1049 SETUP_ARBITRARY_FRAME(argc, argv): Only change here is that
1050 create_new_frame would no longer init extra frame info;
1051 SETUP_ARBITRARY_FRAME would have to do that.
1053 INIT_PREV_FRAME(fromleaf, prev) Replace INIT_EXTRA_FRAME_INFO and
1054 DEPRECATED_INIT_FRAME_PC. This should also return a flag saying
1055 whether to keep the new frame, or whether to discard it, because
1056 on some machines (e.g. mips) it is really awkward to have
1057 FRAME_CHAIN_VALID called *before* INIT_EXTRA_FRAME_INFO (there is
1058 no good way to get information deduced in FRAME_CHAIN_VALID into
1059 the extra fields of the new frame). std_frame_pc(fromleaf, prev)
1061 This is the default setting for INIT_PREV_FRAME. It just does
1062 what the default DEPRECATED_INIT_FRAME_PC does. Some machines
1063 will call it from INIT_PREV_FRAME (either at the beginning, the
1064 end, or in the middle). Some machines won't use it.
1068 /* NOTE: cagney/2002-11-09: Just ignore the above! There is no
1069 reason for things to be this complicated.
1071 The trick is to assume that there is always a frame. Instead of
1072 special casing the inner-most frame, create fake frame
1073 (containing the hardware registers) that is inner to the
1074 user-visible inner-most frame (...) and then unwind from that.
1075 That way architecture code can use use the standard
1076 frame_XX_unwind() functions and not differentiate between the
1077 inner most and any other case.
1079 Since there is always a frame to unwind from, there is always
1080 somewhere (NEXT_FRAME) to store all the info needed to construct
1081 a new (previous) frame without having to first create it. This
1082 means that the convolution below - needing to carefully order a
1083 frame's initialization - isn't needed.
1085 The irony here though, is that FRAME_CHAIN(), at least for a more
1086 up-to-date architecture, always calls FRAME_SAVED_PC(), and
1087 FRAME_SAVED_PC() computes the PC but without first needing the
1088 frame! Instead of the convolution below, we could have simply
1089 called FRAME_SAVED_PC() and been done with it! Note that
1090 FRAME_SAVED_PC() is being superseed by frame_pc_unwind() and that
1091 function does have somewhere to cache that PC value. */
1093 if (DEPRECATED_INIT_FRAME_PC_FIRST_P ())
1094 prev->pc = (DEPRECATED_INIT_FRAME_PC_FIRST (fromleaf, prev));
1096 if (INIT_EXTRA_FRAME_INFO_P ())
1097 INIT_EXTRA_FRAME_INFO (fromleaf, prev);
1099 /* This entry is in the frame queue now, which is good since
1100 FRAME_SAVED_PC may use that queue to figure out its value (see
1101 tm-sparc.h). We want the pc saved in the inferior frame. */
1102 if (DEPRECATED_INIT_FRAME_PC_P ())
1103 prev->pc = DEPRECATED_INIT_FRAME_PC (fromleaf, prev);
1105 /* If ->frame and ->pc are unchanged, we are in the process of
1106 getting ourselves into an infinite backtrace. Some architectures
1107 check this in FRAME_CHAIN or thereabouts, but it seems like there
1108 is no reason this can't be an architecture-independent check. */
1109 if (prev->frame == next_frame->frame
1110 && prev->pc == next_frame->pc)
1112 next_frame->prev = NULL;
1113 obstack_free (&frame_cache_obstack, prev);
1117 /* Initialize the code used to unwind the frame PREV based on the PC
1118 (and probably other architectural information). The PC lets you
1119 check things like the debug info at that point (dwarf2cfi?) and
1120 use that to decide how the frame should be unwound. */
1121 prev->unwind = frame_unwind_find_by_pc (current_gdbarch, prev->pc);
1123 /* NOTE: cagney/2002-11-18: The code segments, found in
1124 create_new_frame and get_prev_frame(), that initializes the
1125 frames type is subtly different. The latter only updates ->type
1126 when it encounters a SIGTRAMP_FRAME or DUMMY_FRAME. This stops
1127 get_prev_frame() overriding the frame's type when the INIT code
1128 has previously set it. This is really somewhat bogus. The
1129 initialization, as seen in create_new_frame(), should occur
1130 before the INIT function has been called. */
1131 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES
1132 && (DEPRECATED_PC_IN_CALL_DUMMY_P ()
1133 ? DEPRECATED_PC_IN_CALL_DUMMY (prev->pc, 0, 0)
1134 : pc_in_dummy_frame (prev->pc)))
1135 prev->type = DUMMY_FRAME;
1138 /* FIXME: cagney/2002-11-10: This should be moved to before the
1139 INIT code above so that the INIT code knows what the frame's
1140 type is (in fact, for a [generic] dummy-frame, the type can
1141 be set and then the entire initialization can be skipped.
1142 Unforunatly, its the INIT code that sets the PC (Hmm, catch
1145 find_pc_partial_function (prev->pc, &name, NULL, NULL);
1146 if (PC_IN_SIGTRAMP (prev->pc, name))
1147 prev->type = SIGTRAMP_FRAME;
1148 /* FIXME: cagney/2002-11-11: Leave prev->type alone. Some
1149 architectures are forcing the frame's type in INIT so we
1150 don't want to override it here. Remember, NORMAL_FRAME == 0,
1151 so it all works (just :-/). Once this initialization is
1152 moved to the start of this function, all this nastness will
1159 /* Return a structure containing various interesting information
1160 about the frame that called NEXT_FRAME. Returns NULL
1161 if there is no such frame. */
1164 get_prev_frame (struct frame_info *next_frame)
1166 struct frame_info *prev_frame;
1168 /* Return the inner-most frame, when the caller passes in NULL. */
1169 /* NOTE: cagney/2002-11-09: Not sure how this would happen. The
1170 caller should have previously obtained a valid frame using
1171 get_selected_frame() and then called this code - only possibility
1172 I can think of is code behaving badly.
1174 NOTE: cagney/2003-01-10: Talk about code behaving badly. Check
1175 block_innermost_frame(). It does the sequence: frame = NULL;
1176 while (1) { frame = get_prev_frame (frame); .... }. Ulgh! Why
1177 it couldn't be written better, I don't know.
1179 NOTE: cagney/2003-01-11: I suspect what is happening is
1180 block_innermost_frame() is, when the target has no state
1181 (registers, memory, ...), still calling this function. The
1182 assumption being that this function will return NULL indicating
1183 that a frame isn't possible, rather than checking that the target
1184 has state and then calling get_current_frame() and
1185 get_prev_frame(). This is a guess mind. */
1186 if (next_frame == NULL)
1188 /* NOTE: cagney/2002-11-09: There was a code segment here that
1189 would error out when CURRENT_FRAME was NULL. The comment
1190 that went with it made the claim ...
1192 ``This screws value_of_variable, which just wants a nice
1193 clean NULL return from block_innermost_frame if there are no
1194 frames. I don't think I've ever seen this message happen
1195 otherwise. And returning NULL here is a perfectly legitimate
1198 Per the above, this code shouldn't even be called with a NULL
1200 return current_frame;
1203 /* There is always a frame. If this assertion fails, suspect that
1204 something should be calling get_selected_frame() or
1205 get_current_frame(). */
1206 gdb_assert (next_frame != NULL);
1208 if (next_frame->level >= 0
1209 && !backtrace_below_main
1210 && inside_main_func (get_frame_pc (next_frame)))
1211 /* Don't unwind past main(), bug always unwind the sentinel frame.
1212 Note, this is done _before_ the frame has been marked as
1213 previously unwound. That way if the user later decides to
1214 allow unwinds past main(), that just happens. */
1217 /* Only try to do the unwind once. */
1218 if (next_frame->prev_p)
1219 return next_frame->prev;
1220 next_frame->prev_p = 1;
1222 /* If we're inside the entry file, it isn't valid. */
1223 /* NOTE: drow/2002-12-25: should there be a way to disable this
1224 check? It assumes a single small entry file, and the way some
1225 debug readers (e.g. dbxread) figure out which object is the
1226 entry file is somewhat hokey. */
1227 /* NOTE: cagney/2003-01-10: If there is a way of disabling this test
1228 then it should probably be moved to before the ->prev_p test,
1230 if (inside_entry_file (get_frame_pc (next_frame)))
1233 /* If any of the old frame initialization methods are around, use
1234 the legacy get_prev_frame method. Just don't try to unwind a
1235 sentinel frame using that method - it doesn't work. All sentinal
1236 frames use the new unwind code. */
1237 if ((DEPRECATED_INIT_FRAME_PC_P ()
1238 || DEPRECATED_INIT_FRAME_PC_FIRST_P ()
1239 || INIT_EXTRA_FRAME_INFO_P ()
1240 || FRAME_CHAIN_P ())
1241 && next_frame->level >= 0)
1242 return legacy_get_prev_frame (next_frame);
1244 /* Allocate the new frame but do not wire it in to the frame chain.
1245 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
1246 frame->next to pull some fancy tricks (of course such code is, by
1247 definition, recursive). Try to prevent it.
1249 There is no reason to worry about memory leaks, should the
1250 remainder of the function fail. The allocated memory will be
1251 quickly reclaimed when the frame cache is flushed, and the `we've
1252 been here before' check above will stop repeated memory
1253 allocation calls. */
1254 prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info);
1255 prev_frame->level = next_frame->level + 1;
1257 /* Try to unwind the PC. If that doesn't work, assume we've reached
1258 the oldest frame and simply return. Is there a better sentinal
1259 value? The unwound PC value is then used to initialize the new
1260 previous frame's type.
1262 Note that the pc-unwind is intentionally performed before the
1263 frame chain. This is ok since, for old targets, both
1264 frame_pc_unwind (nee, FRAME_SAVED_PC) and FRAME_CHAIN()) assume
1265 NEXT_FRAME's data structures have already been initialized (using
1266 INIT_EXTRA_FRAME_INFO) and hence the call order doesn't matter.
1268 By unwinding the PC first, it becomes possible to, in the case of
1269 a dummy frame, avoid also unwinding the frame ID. This is
1270 because (well ignoring the PPC) a dummy frame can be located
1271 using NEXT_FRAME's frame ID. */
1273 prev_frame->pc = frame_pc_unwind (next_frame);
1274 if (prev_frame->pc == 0)
1275 /* The allocated PREV_FRAME will be reclaimed when the frame
1276 obstack is next purged. */
1278 prev_frame->type = frame_type_from_pc (prev_frame->pc);
1280 /* Set the unwind functions based on that identified PC. */
1281 prev_frame->unwind = frame_unwind_find_by_pc (current_gdbarch,
1284 /* FIXME: cagney/2003-01-13: A dummy frame doesn't need to unwind
1285 the frame ID because the frame ID comes from the previous frame.
1286 The other frames do though. True? */
1288 /* FIXME: cagney/2002-12-18: Instead of this hack, should just
1289 save the frame ID directly. */
1290 struct frame_id id = frame_id_unwind (next_frame);
1291 if (!frame_id_p (id))
1293 prev_frame->frame = id.base;
1297 next_frame->prev = prev_frame;
1298 prev_frame->next = next_frame;
1300 /* FIXME: cagney/2002-01-19: This call will go away. Instead of
1301 initializing extra info, all frames will use the frame_cache
1302 (passed to the unwind functions) to store additional frame info.
1303 Unfortunatly legacy targets can't use legacy_get_prev_frame() to
1304 unwind the sentinel frame and, consequently, are forced to take
1305 this code path and rely on the below call to INIT_EXTR_FRAME_INFO
1306 to initialize the inner-most frame. */
1307 if (INIT_EXTRA_FRAME_INFO_P ())
1309 gdb_assert (prev_frame->level == 0);
1310 INIT_EXTRA_FRAME_INFO (0, prev_frame);
1317 get_frame_pc (struct frame_info *frame)
1323 pc_notcurrent (struct frame_info *frame)
1325 /* If FRAME is not the innermost frame, that normally means that
1326 FRAME->pc points at the return instruction (which is *after* the
1327 call instruction), and we want to get the line containing the
1328 call (because the call is where the user thinks the program is).
1329 However, if the next frame is either a SIGTRAMP_FRAME or a
1330 DUMMY_FRAME, then the next frame will contain a saved interrupt
1331 PC and such a PC indicates the current (rather than next)
1332 instruction/line, consequently, for such cases, want to get the
1333 line containing fi->pc. */
1334 struct frame_info *next = get_next_frame (frame);
1335 int notcurrent = (next != NULL && get_frame_type (next) == NORMAL_FRAME);
1340 find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal)
1342 (*sal) = find_pc_line (frame->pc, pc_notcurrent (frame));
1345 /* Per "frame.h", return the ``address'' of the frame. Code should
1346 really be using get_frame_id(). */
1348 get_frame_base (struct frame_info *fi)
1353 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
1354 or -1 for a NULL frame. */
1357 frame_relative_level (struct frame_info *fi)
1366 get_frame_type (struct frame_info *frame)
1368 /* Some targets still don't use [generic] dummy frames. Catch them
1370 if (!DEPRECATED_USE_GENERIC_DUMMY_FRAMES
1371 && deprecated_frame_in_dummy (frame))
1377 deprecated_set_frame_type (struct frame_info *frame, enum frame_type type)
1379 /* Arrrg! See comment in "frame.h". */
1383 #ifdef FRAME_FIND_SAVED_REGS
1384 /* XXX - deprecated. This is a compatibility function for targets
1385 that do not yet implement FRAME_INIT_SAVED_REGS. */
1386 /* Find the addresses in which registers are saved in FRAME. */
1389 deprecated_get_frame_saved_regs (struct frame_info *frame,
1390 struct frame_saved_regs *saved_regs_addr)
1392 if (frame->saved_regs == NULL)
1394 frame->saved_regs = (CORE_ADDR *)
1395 frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS);
1397 if (saved_regs_addr == NULL)
1399 struct frame_saved_regs saved_regs;
1400 FRAME_FIND_SAVED_REGS (frame, saved_regs);
1401 memcpy (frame->saved_regs, &saved_regs, SIZEOF_FRAME_SAVED_REGS);
1405 FRAME_FIND_SAVED_REGS (frame, *saved_regs_addr);
1406 memcpy (frame->saved_regs, saved_regs_addr, SIZEOF_FRAME_SAVED_REGS);
1411 struct frame_extra_info *
1412 get_frame_extra_info (struct frame_info *fi)
1414 return fi->extra_info;
1417 struct frame_extra_info *
1418 frame_extra_info_zalloc (struct frame_info *fi, long size)
1420 fi->extra_info = frame_obstack_zalloc (size);
1421 return fi->extra_info;
1425 deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc)
1427 /* See comment in "frame.h". */
1428 gdb_assert (frame->next != NULL);
1433 deprecated_update_frame_base_hack (struct frame_info *frame, CORE_ADDR base)
1435 /* See comment in "frame.h". */
1436 frame->frame = base;
1440 deprecated_set_frame_saved_regs_hack (struct frame_info *frame,
1441 CORE_ADDR *saved_regs)
1443 frame->saved_regs = saved_regs;
1447 deprecated_set_frame_extra_info_hack (struct frame_info *frame,
1448 struct frame_extra_info *extra_info)
1450 frame->extra_info = extra_info;
1454 deprecated_set_frame_next_hack (struct frame_info *fi,
1455 struct frame_info *next)
1461 deprecated_set_frame_prev_hack (struct frame_info *fi,
1462 struct frame_info *prev)
1468 deprecated_get_frame_context (struct frame_info *fi)
1474 deprecated_set_frame_context (struct frame_info *fi,
1475 struct context *context)
1477 fi->context = context;
1481 deprecated_frame_xmalloc (void)
1483 struct frame_info *frame = XMALLOC (struct frame_info);
1484 memset (frame, 0, sizeof (struct frame_info));
1489 deprecated_frame_xmalloc_with_cleanup (long sizeof_saved_regs,
1490 long sizeof_extra_info)
1492 struct frame_info *frame = deprecated_frame_xmalloc ();
1493 make_cleanup (xfree, frame);
1494 if (sizeof_saved_regs > 0)
1496 frame->saved_regs = xcalloc (1, sizeof_saved_regs);
1497 make_cleanup (xfree, frame->saved_regs);
1499 if (sizeof_extra_info > 0)
1501 frame->extra_info = xcalloc (1, sizeof_extra_info);
1502 make_cleanup (xfree, frame->extra_info);
1508 _initialize_frame (void)
1510 obstack_init (&frame_cache_obstack);
1512 /* FIXME: cagney/2003-01-19: This command needs a rename. Suggest
1513 `set backtrace {past,beyond,...}-main'. Also suggest adding `set
1514 backtrace ...-start' to control backtraces past start. The
1515 problem with `below' is that it stops the `up' command. */
1517 add_setshow_boolean_cmd ("backtrace-below-main", class_obscure,
1518 &backtrace_below_main, "\
1519 Set whether backtraces should continue past \"main\".\n\
1520 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
1521 the backtrace at \"main\". Set this variable if you need to see the rest\n\
1522 of the stack trace.", "\
1523 Show whether backtraces should continue past \"main\".\n\
1524 Normally the caller of \"main\" is not of interest, so GDB will terminate\n\
1525 the backtrace at \"main\". Set this variable if you need to see the rest\n\
1526 of the stack trace.",
1527 NULL, NULL, &setlist, &showlist);