994 lines
32 KiB
C
994 lines
32 KiB
C
/* Cache and manage frames for GDB, the GNU debugger.
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Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000,
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2001, 2002 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "frame.h"
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#include "target.h"
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#include "value.h"
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#include "inferior.h" /* for inferior_ptid */
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#include "regcache.h"
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#include "gdb_assert.h"
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#include "gdb_string.h"
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#include "builtin-regs.h"
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#include "gdb_obstack.h"
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#include "dummy-frame.h"
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#include "gdbcore.h"
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#include "annotate.h"
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/* Return a frame uniq ID that can be used to, later re-find the
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frame. */
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void
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get_frame_id (struct frame_info *fi, struct frame_id *id)
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{
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if (fi == NULL)
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{
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id->base = 0;
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id->pc = 0;
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}
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else
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{
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id->base = FRAME_FP (fi);
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id->pc = fi->pc;
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}
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}
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struct frame_info *
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frame_find_by_id (struct frame_id id)
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{
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struct frame_info *frame;
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/* ZERO denotes the null frame, let the caller decide what to do
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about it. Should it instead return get_current_frame()? */
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if (id.base == 0 && id.pc == 0)
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return NULL;
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for (frame = get_current_frame ();
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frame != NULL;
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frame = get_prev_frame (frame))
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{
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if (INNER_THAN (FRAME_FP (frame), id.base))
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/* ``inner/current < frame < id.base''. Keep looking along
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the frame chain. */
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continue;
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if (INNER_THAN (id.base, FRAME_FP (frame)))
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/* ``inner/current < id.base < frame''. Oops, gone past it.
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Just give up. */
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return NULL;
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/* FIXME: cagney/2002-04-21: This isn't sufficient. It should
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use id.pc to check that the two frames belong to the same
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function. Otherwise we'll do things like match dummy frames
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or mis-match frameless functions. However, until someone
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notices, stick with the existing behavour. */
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return frame;
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}
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return NULL;
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}
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CORE_ADDR
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frame_pc_unwind (struct frame_info *frame)
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{
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if (!frame->pc_unwind_cache_p)
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{
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frame->pc_unwind_cache = frame->pc_unwind (frame, &frame->unwind_cache);
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frame->pc_unwind_cache_p = 1;
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}
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return frame->pc_unwind_cache;
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}
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void
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frame_register_unwind (struct frame_info *frame, int regnum,
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int *optimizedp, enum lval_type *lvalp,
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CORE_ADDR *addrp, int *realnump, void *bufferp)
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{
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struct frame_unwind_cache *cache;
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/* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
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that the value proper does not need to be fetched. */
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gdb_assert (optimizedp != NULL);
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gdb_assert (lvalp != NULL);
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gdb_assert (addrp != NULL);
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gdb_assert (realnump != NULL);
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/* gdb_assert (bufferp != NULL); */
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/* NOTE: cagney/2002-04-14: It would be nice if, instead of a
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special case, there was always an inner frame dedicated to the
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hardware registers. Unfortunatly, there is too much unwind code
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around that looks up/down the frame chain while making the
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assumption that each frame level is using the same unwind code. */
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if (frame == NULL)
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{
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/* We're in the inner-most frame, get the value direct from the
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register cache. */
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*optimizedp = 0;
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*lvalp = lval_register;
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/* ULGH! Code uses the offset into the raw register byte array
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as a way of identifying a register. */
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*addrp = REGISTER_BYTE (regnum);
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/* Should this code test ``register_cached (regnum) < 0'' and do
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something like set realnum to -1 when the register isn't
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available? */
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*realnump = regnum;
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if (bufferp)
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deprecated_read_register_gen (regnum, bufferp);
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return;
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}
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/* Ask this frame to unwind its register. */
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frame->register_unwind (frame, &frame->unwind_cache, regnum,
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optimizedp, lvalp, addrp, realnump, bufferp);
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}
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void
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frame_register (struct frame_info *frame, int regnum,
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int *optimizedp, enum lval_type *lvalp,
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CORE_ADDR *addrp, int *realnump, void *bufferp)
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{
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/* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
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that the value proper does not need to be fetched. */
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gdb_assert (optimizedp != NULL);
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gdb_assert (lvalp != NULL);
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gdb_assert (addrp != NULL);
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gdb_assert (realnump != NULL);
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/* gdb_assert (bufferp != NULL); */
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/* Ulgh! Old code that, for lval_register, sets ADDRP to the offset
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of the register in the register cache. It should instead return
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the REGNUM corresponding to that register. Translate the . */
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if (GET_SAVED_REGISTER_P ())
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{
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GET_SAVED_REGISTER (bufferp, optimizedp, addrp, frame, regnum, lvalp);
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/* Compute the REALNUM if the caller wants it. */
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if (*lvalp == lval_register)
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{
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int regnum;
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for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++)
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{
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if (*addrp == register_offset_hack (current_gdbarch, regnum))
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{
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*realnump = regnum;
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return;
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}
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}
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internal_error (__FILE__, __LINE__,
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"Failed to compute the register number corresponding"
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" to 0x%s", paddr_d (*addrp));
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}
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*realnump = -1;
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return;
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}
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/* Reached the the bottom (youngest, inner most) of the frame chain
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(youngest, inner most) frame, go direct to the hardware register
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cache (do not pass go, do not try to cache the value, ...). The
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unwound value would have been cached in frame->next but that
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doesn't exist. This doesn't matter as the hardware register
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cache is stopping any unnecessary accesses to the target. */
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/* NOTE: cagney/2002-04-14: It would be nice if, instead of a
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special case, there was always an inner frame dedicated to the
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hardware registers. Unfortunatly, there is too much unwind code
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around that looks up/down the frame chain while making the
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assumption that each frame level is using the same unwind code. */
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if (frame == NULL)
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frame_register_unwind (NULL, regnum, optimizedp, lvalp, addrp, realnump,
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bufferp);
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else
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frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
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realnump, bufferp);
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}
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void
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frame_unwind_signed_register (struct frame_info *frame, int regnum,
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LONGEST *val)
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{
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int optimized;
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CORE_ADDR addr;
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int realnum;
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enum lval_type lval;
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void *buf = alloca (MAX_REGISTER_RAW_SIZE);
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frame_register_unwind (frame, regnum, &optimized, &lval, &addr,
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&realnum, buf);
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(*val) = extract_signed_integer (buf, REGISTER_VIRTUAL_SIZE (regnum));
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}
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void
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frame_unwind_unsigned_register (struct frame_info *frame, int regnum,
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ULONGEST *val)
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{
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int optimized;
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CORE_ADDR addr;
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int realnum;
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enum lval_type lval;
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void *buf = alloca (MAX_REGISTER_RAW_SIZE);
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frame_register_unwind (frame, regnum, &optimized, &lval, &addr,
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&realnum, buf);
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(*val) = extract_unsigned_integer (buf, REGISTER_VIRTUAL_SIZE (regnum));
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}
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void
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frame_read_unsigned_register (struct frame_info *frame, int regnum,
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ULONGEST *val)
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{
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/* NOTE: cagney/2002-10-31: There is a bit of dogma here - there is
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always a frame. Both this, and the equivalent
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frame_read_signed_register() function, can only be called with a
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valid frame. If, for some reason, this function is called
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without a frame then the problem isn't here, but rather in the
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caller. It should of first created a frame and then passed that
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in. */
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/* NOTE: cagney/2002-10-31: As a side bar, keep in mind that the
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``current_frame'' should not be treated as a special case. While
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``get_next_frame (current_frame) == NULL'' currently holds, it
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should, as far as possible, not be relied upon. In the future,
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``get_next_frame (current_frame)'' may instead simply return a
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normal frame object that simply always gets register values from
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the register cache. Consequently, frame code should try to avoid
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tests like ``if get_next_frame() == NULL'' and instead just rely
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on recursive frame calls (like the below code) when manipulating
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a frame chain. */
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gdb_assert (frame != NULL);
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frame_unwind_unsigned_register (get_next_frame (frame), regnum, val);
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}
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void
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frame_read_signed_register (struct frame_info *frame, int regnum,
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LONGEST *val)
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{
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/* See note in frame_read_unsigned_register(). */
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gdb_assert (frame != NULL);
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frame_unwind_signed_register (get_next_frame (frame), regnum, val);
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}
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static void
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generic_unwind_get_saved_register (char *raw_buffer,
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int *optimizedp,
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CORE_ADDR *addrp,
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struct frame_info *frame,
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int regnum,
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enum lval_type *lvalp)
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{
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int optimizedx;
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CORE_ADDR addrx;
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int realnumx;
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enum lval_type lvalx;
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if (!target_has_registers)
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error ("No registers.");
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/* Keep things simple, ensure that all the pointers (except valuep)
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are non NULL. */
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if (optimizedp == NULL)
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optimizedp = &optimizedx;
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if (lvalp == NULL)
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lvalp = &lvalx;
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if (addrp == NULL)
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addrp = &addrx;
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/* Reached the the bottom (youngest, inner most) of the frame chain
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(youngest, inner most) frame, go direct to the hardware register
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cache (do not pass go, do not try to cache the value, ...). The
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unwound value would have been cached in frame->next but that
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doesn't exist. This doesn't matter as the hardware register
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cache is stopping any unnecessary accesses to the target. */
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/* NOTE: cagney/2002-04-14: It would be nice if, instead of a
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special case, there was always an inner frame dedicated to the
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hardware registers. Unfortunatly, there is too much unwind code
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around that looks up/down the frame chain while making the
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assumption that each frame level is using the same unwind code. */
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if (frame == NULL)
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frame_register_unwind (NULL, regnum, optimizedp, lvalp, addrp, &realnumx,
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raw_buffer);
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else
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frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
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&realnumx, raw_buffer);
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}
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void
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get_saved_register (char *raw_buffer,
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int *optimized,
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CORE_ADDR *addrp,
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struct frame_info *frame,
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int regnum,
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enum lval_type *lval)
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{
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if (GET_SAVED_REGISTER_P ())
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{
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GET_SAVED_REGISTER (raw_buffer, optimized, addrp, frame, regnum, lval);
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return;
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}
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generic_unwind_get_saved_register (raw_buffer, optimized, addrp, frame,
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regnum, lval);
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}
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/* frame_register_read ()
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Find and return the value of REGNUM for the specified stack frame.
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The number of bytes copied is REGISTER_RAW_SIZE (REGNUM).
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Returns 0 if the register value could not be found. */
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int
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frame_register_read (struct frame_info *frame, int regnum, void *myaddr)
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{
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int optimized;
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enum lval_type lval;
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CORE_ADDR addr;
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int realnum;
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frame_register (frame, regnum, &optimized, &lval, &addr, &realnum, myaddr);
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/* FIXME: cagney/2002-05-15: This test, is just bogus.
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It indicates that the target failed to supply a value for a
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register because it was "not available" at this time. Problem
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is, the target still has the register and so get saved_register()
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may be returning a value saved on the stack. */
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if (register_cached (regnum) < 0)
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return 0; /* register value not available */
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return !optimized;
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}
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/* Map between a frame register number and its name. A frame register
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space is a superset of the cooked register space --- it also
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includes builtin registers. */
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int
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frame_map_name_to_regnum (const char *name, int len)
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{
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int i;
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/* Search register name space. */
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for (i = 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++)
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if (REGISTER_NAME (i) && len == strlen (REGISTER_NAME (i))
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&& strncmp (name, REGISTER_NAME (i), len) == 0)
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{
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return i;
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}
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/* Try builtin registers. */
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i = builtin_reg_map_name_to_regnum (name, len);
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if (i >= 0)
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{
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/* A builtin register doesn't fall into the architecture's
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register range. */
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gdb_assert (i >= NUM_REGS + NUM_PSEUDO_REGS);
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return i;
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}
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return -1;
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}
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const char *
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frame_map_regnum_to_name (int regnum)
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{
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if (regnum < 0)
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return NULL;
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if (regnum < NUM_REGS + NUM_PSEUDO_REGS)
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return REGISTER_NAME (regnum);
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return builtin_reg_map_regnum_to_name (regnum);
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}
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/* Info about the innermost stack frame (contents of FP register) */
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static struct frame_info *current_frame;
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/* Cache for frame addresses already read by gdb. Valid only while
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inferior is stopped. Control variables for the frame cache should
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be local to this module. */
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static struct obstack frame_cache_obstack;
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void *
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frame_obstack_alloc (unsigned long size)
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{
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return obstack_alloc (&frame_cache_obstack, size);
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}
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void
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frame_saved_regs_zalloc (struct frame_info *fi)
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{
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fi->saved_regs = (CORE_ADDR *)
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frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
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memset (fi->saved_regs, 0, SIZEOF_FRAME_SAVED_REGS);
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}
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/* Return the innermost (currently executing) stack frame. */
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struct frame_info *
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get_current_frame (void)
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{
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if (current_frame == NULL)
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{
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if (target_has_stack)
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current_frame = create_new_frame (read_fp (), read_pc ());
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else
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error ("No stack.");
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}
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return current_frame;
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}
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void
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set_current_frame (struct frame_info *frame)
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{
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current_frame = frame;
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}
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/* Return the register saved in the simplistic ``saved_regs'' cache.
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If the value isn't here AND a value is needed, try the next inner
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most frame. */
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static void
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frame_saved_regs_register_unwind (struct frame_info *frame, void **cache,
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int regnum, int *optimizedp,
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enum lval_type *lvalp, CORE_ADDR *addrp,
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int *realnump, void *bufferp)
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{
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/* There is always a frame at this point. And THIS is the frame
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we're interested in. */
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gdb_assert (frame != NULL);
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/* If we're using generic dummy frames, we'd better not be in a call
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dummy. (generic_call_dummy_register_unwind ought to have been called
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instead.) */
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gdb_assert (!(USE_GENERIC_DUMMY_FRAMES
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&& PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame)));
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/* Load the saved_regs register cache. */
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if (frame->saved_regs == NULL)
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FRAME_INIT_SAVED_REGS (frame);
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if (frame->saved_regs != NULL
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&& frame->saved_regs[regnum] != 0)
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{
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if (regnum == SP_REGNUM)
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{
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/* SP register treated specially. */
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*optimizedp = 0;
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*lvalp = not_lval;
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*addrp = 0;
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*realnump = -1;
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if (bufferp != NULL)
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store_address (bufferp, REGISTER_RAW_SIZE (regnum),
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frame->saved_regs[regnum]);
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}
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else
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{
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/* Any other register is saved in memory, fetch it but cache
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a local copy of its value. */
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*optimizedp = 0;
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*lvalp = lval_memory;
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*addrp = frame->saved_regs[regnum];
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*realnump = -1;
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if (bufferp != NULL)
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{
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#if 1
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/* Save each register value, as it is read in, in a
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frame based cache. */
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void **regs = (*cache);
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if (regs == NULL)
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{
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int sizeof_cache = ((NUM_REGS + NUM_PSEUDO_REGS)
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* sizeof (void *));
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regs = frame_obstack_alloc (sizeof_cache);
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memset (regs, 0, sizeof_cache);
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(*cache) = regs;
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}
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if (regs[regnum] == NULL)
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{
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regs[regnum]
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= frame_obstack_alloc (REGISTER_RAW_SIZE (regnum));
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read_memory (frame->saved_regs[regnum], regs[regnum],
|
|
REGISTER_RAW_SIZE (regnum));
|
|
}
|
|
memcpy (bufferp, regs[regnum], REGISTER_RAW_SIZE (regnum));
|
|
#else
|
|
/* Read the value in from memory. */
|
|
read_memory (frame->saved_regs[regnum], bufferp,
|
|
REGISTER_RAW_SIZE (regnum));
|
|
#endif
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
/* No luck, assume this and the next frame have the same register
|
|
value. If a value is needed, pass the request on down the chain;
|
|
otherwise just return an indication that the value is in the same
|
|
register as the next frame. */
|
|
if (bufferp == NULL)
|
|
{
|
|
*optimizedp = 0;
|
|
*lvalp = lval_register;
|
|
*addrp = 0;
|
|
*realnump = regnum;
|
|
}
|
|
else
|
|
{
|
|
frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
|
|
realnump, bufferp);
|
|
}
|
|
}
|
|
|
|
static CORE_ADDR
|
|
frame_saved_regs_pc_unwind (struct frame_info *frame, void **cache)
|
|
{
|
|
return FRAME_SAVED_PC (frame);
|
|
}
|
|
|
|
/* Function: get_saved_register
|
|
Find register number REGNUM relative to FRAME and put its (raw,
|
|
target format) contents in *RAW_BUFFER.
|
|
|
|
Set *OPTIMIZED if the variable was optimized out (and thus can't be
|
|
fetched). Note that this is never set to anything other than zero
|
|
in this implementation.
|
|
|
|
Set *LVAL to lval_memory, lval_register, or not_lval, depending on
|
|
whether the value was fetched from memory, from a register, or in a
|
|
strange and non-modifiable way (e.g. a frame pointer which was
|
|
calculated rather than fetched). We will use not_lval for values
|
|
fetched from generic dummy frames.
|
|
|
|
Set *ADDRP to the address, either in memory or as a REGISTER_BYTE
|
|
offset into the registers array. If the value is stored in a dummy
|
|
frame, set *ADDRP to zero.
|
|
|
|
To use this implementation, define a function called
|
|
"get_saved_register" in your target code, which simply passes all
|
|
of its arguments to this function.
|
|
|
|
The argument RAW_BUFFER must point to aligned memory. */
|
|
|
|
void
|
|
deprecated_generic_get_saved_register (char *raw_buffer, int *optimized,
|
|
CORE_ADDR *addrp,
|
|
struct frame_info *frame, int regnum,
|
|
enum lval_type *lval)
|
|
{
|
|
if (!target_has_registers)
|
|
error ("No registers.");
|
|
|
|
/* Normal systems don't optimize out things with register numbers. */
|
|
if (optimized != NULL)
|
|
*optimized = 0;
|
|
|
|
if (addrp) /* default assumption: not found in memory */
|
|
*addrp = 0;
|
|
|
|
/* Note: since the current frame's registers could only have been
|
|
saved by frames INTERIOR TO the current frame, we skip examining
|
|
the current frame itself: otherwise, we would be getting the
|
|
previous frame's registers which were saved by the current frame. */
|
|
|
|
while (frame && ((frame = frame->next) != NULL))
|
|
{
|
|
if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame))
|
|
{
|
|
if (lval) /* found it in a CALL_DUMMY frame */
|
|
*lval = not_lval;
|
|
if (raw_buffer)
|
|
/* FIXME: cagney/2002-06-26: This should be via the
|
|
gdbarch_register_read() method so that it, on the fly,
|
|
constructs either a raw or pseudo register from the raw
|
|
register cache. */
|
|
regcache_raw_read (generic_find_dummy_frame (frame->pc,
|
|
frame->frame),
|
|
regnum, raw_buffer);
|
|
return;
|
|
}
|
|
|
|
FRAME_INIT_SAVED_REGS (frame);
|
|
if (frame->saved_regs != NULL
|
|
&& frame->saved_regs[regnum] != 0)
|
|
{
|
|
if (lval) /* found it saved on the stack */
|
|
*lval = lval_memory;
|
|
if (regnum == SP_REGNUM)
|
|
{
|
|
if (raw_buffer) /* SP register treated specially */
|
|
store_address (raw_buffer, REGISTER_RAW_SIZE (regnum),
|
|
frame->saved_regs[regnum]);
|
|
}
|
|
else
|
|
{
|
|
if (addrp) /* any other register */
|
|
*addrp = frame->saved_regs[regnum];
|
|
if (raw_buffer)
|
|
read_memory (frame->saved_regs[regnum], raw_buffer,
|
|
REGISTER_RAW_SIZE (regnum));
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* If we get thru the loop to this point, it means the register was
|
|
not saved in any frame. Return the actual live-register value. */
|
|
|
|
if (lval) /* found it in a live register */
|
|
*lval = lval_register;
|
|
if (addrp)
|
|
*addrp = REGISTER_BYTE (regnum);
|
|
if (raw_buffer)
|
|
deprecated_read_register_gen (regnum, raw_buffer);
|
|
}
|
|
|
|
/* Using the PC, select a mechanism for unwinding a frame returning
|
|
the previous frame. The register unwind function should, on
|
|
demand, initialize the ->context object. */
|
|
|
|
static void
|
|
set_unwind_by_pc (CORE_ADDR pc, CORE_ADDR fp,
|
|
frame_register_unwind_ftype **unwind_register,
|
|
frame_pc_unwind_ftype **unwind_pc)
|
|
{
|
|
if (!USE_GENERIC_DUMMY_FRAMES)
|
|
{
|
|
/* Still need to set this to something. The ``info frame'' code
|
|
calls this function to find out where the saved registers are.
|
|
Hopefully this is robust enough to stop any core dumps and
|
|
return vaguely correct values.. */
|
|
*unwind_register = frame_saved_regs_register_unwind;
|
|
*unwind_pc = frame_saved_regs_pc_unwind;
|
|
}
|
|
else if (PC_IN_CALL_DUMMY (pc, fp, fp))
|
|
{
|
|
*unwind_register = dummy_frame_register_unwind;
|
|
*unwind_pc = dummy_frame_pc_unwind;
|
|
}
|
|
else
|
|
{
|
|
*unwind_register = frame_saved_regs_register_unwind;
|
|
*unwind_pc = frame_saved_regs_pc_unwind;
|
|
}
|
|
}
|
|
|
|
/* Create an arbitrary (i.e. address specified by user) or innermost frame.
|
|
Always returns a non-NULL value. */
|
|
|
|
struct frame_info *
|
|
create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
|
|
{
|
|
struct frame_info *fi;
|
|
char *name;
|
|
|
|
fi = (struct frame_info *)
|
|
obstack_alloc (&frame_cache_obstack,
|
|
sizeof (struct frame_info));
|
|
|
|
/* Zero all fields by default. */
|
|
memset (fi, 0, sizeof (struct frame_info));
|
|
|
|
fi->frame = addr;
|
|
fi->pc = pc;
|
|
find_pc_partial_function (pc, &name, (CORE_ADDR *) NULL, (CORE_ADDR *) NULL);
|
|
fi->signal_handler_caller = PC_IN_SIGTRAMP (fi->pc, name);
|
|
|
|
if (INIT_EXTRA_FRAME_INFO_P ())
|
|
INIT_EXTRA_FRAME_INFO (0, fi);
|
|
|
|
/* Select/initialize an unwind function. */
|
|
set_unwind_by_pc (fi->pc, fi->frame, &fi->register_unwind,
|
|
&fi->pc_unwind);
|
|
|
|
return fi;
|
|
}
|
|
|
|
/* Return the frame that FRAME calls (NULL if FRAME is the innermost
|
|
frame). */
|
|
|
|
struct frame_info *
|
|
get_next_frame (struct frame_info *frame)
|
|
{
|
|
return frame->next;
|
|
}
|
|
|
|
/* Flush the entire frame cache. */
|
|
|
|
void
|
|
flush_cached_frames (void)
|
|
{
|
|
/* Since we can't really be sure what the first object allocated was */
|
|
obstack_free (&frame_cache_obstack, 0);
|
|
obstack_init (&frame_cache_obstack);
|
|
|
|
current_frame = NULL; /* Invalidate cache */
|
|
select_frame (NULL);
|
|
annotate_frames_invalid ();
|
|
}
|
|
|
|
/* Flush the frame cache, and start a new one if necessary. */
|
|
|
|
void
|
|
reinit_frame_cache (void)
|
|
{
|
|
flush_cached_frames ();
|
|
|
|
/* FIXME: The inferior_ptid test is wrong if there is a corefile. */
|
|
if (PIDGET (inferior_ptid) != 0)
|
|
{
|
|
select_frame (get_current_frame ());
|
|
}
|
|
}
|
|
|
|
/* Return a structure containing various interesting information
|
|
about the frame that called NEXT_FRAME. Returns NULL
|
|
if there is no such frame. */
|
|
|
|
struct frame_info *
|
|
get_prev_frame (struct frame_info *next_frame)
|
|
{
|
|
CORE_ADDR address = 0;
|
|
struct frame_info *prev;
|
|
int fromleaf;
|
|
char *name;
|
|
|
|
/* Return the inner-most frame, when the caller passes in NULL. */
|
|
/* NOTE: cagney/2002-11-09: Not sure how this would happen. The
|
|
caller should have previously obtained a valid frame using
|
|
get_selected_frame() and then called this code - only possibility
|
|
I can think of is code behaving badly. */
|
|
if (next_frame == NULL)
|
|
{
|
|
/* NOTE: cagney/2002-11-09: There was a code segment here that
|
|
would error out when CURRENT_FRAME was NULL. The comment
|
|
that went with it made the claim ...
|
|
|
|
``This screws value_of_variable, which just wants a nice
|
|
clean NULL return from block_innermost_frame if there are no
|
|
frames. I don't think I've ever seen this message happen
|
|
otherwise. And returning NULL here is a perfectly legitimate
|
|
thing to do.''
|
|
|
|
Per the above, this code shouldn't even be called with a NULL
|
|
NEXT_FRAME. */
|
|
return current_frame;
|
|
}
|
|
|
|
/* Only try to do the unwind once. */
|
|
if (next_frame->prev_p)
|
|
return next_frame->prev;
|
|
next_frame->prev_p = 1;
|
|
|
|
/* On some machines it is possible to call a function without
|
|
setting up a stack frame for it. On these machines, we
|
|
define this macro to take two args; a frameinfo pointer
|
|
identifying a frame and a variable to set or clear if it is
|
|
or isn't leafless. */
|
|
|
|
/* Still don't want to worry about this except on the innermost
|
|
frame. This macro will set FROMLEAF if NEXT_FRAME is a frameless
|
|
function invocation. */
|
|
if (next_frame->next == NULL)
|
|
/* FIXME: 2002-11-09: Frameless functions can occure anywhere in
|
|
the frame chain, not just the inner most frame! The generic,
|
|
per-architecture, frame code should handle this and the below
|
|
should simply be removed. */
|
|
fromleaf = FRAMELESS_FUNCTION_INVOCATION (next_frame);
|
|
else
|
|
fromleaf = 0;
|
|
|
|
if (fromleaf)
|
|
/* A frameless inner-most frame. The `FP' (which isn't an
|
|
architecture frame-pointer register!) of the caller is the same
|
|
as the callee. */
|
|
/* FIXME: 2002-11-09: There isn't any reason to special case this
|
|
edge condition. Instead the per-architecture code should hande
|
|
it locally. */
|
|
address = FRAME_FP (next_frame);
|
|
else
|
|
{
|
|
/* Two macros defined in tm.h specify the machine-dependent
|
|
actions to be performed here.
|
|
|
|
First, get the frame's chain-pointer.
|
|
|
|
If that is zero, the frame is the outermost frame or a leaf
|
|
called by the outermost frame. This means that if start
|
|
calls main without a frame, we'll return 0 (which is fine
|
|
anyway).
|
|
|
|
Nope; there's a problem. This also returns when the current
|
|
routine is a leaf of main. This is unacceptable. We move
|
|
this to after the ffi test; I'd rather have backtraces from
|
|
start go curfluy than have an abort called from main not show
|
|
main. */
|
|
address = FRAME_CHAIN (next_frame);
|
|
|
|
/* FIXME: cagney/2002-06-08: There should be two tests here.
|
|
The first would check for a valid frame chain based on a user
|
|
selectable policy. The default being ``stop at main'' (as
|
|
implemented by generic_func_frame_chain_valid()). Other
|
|
policies would be available - stop at NULL, .... The second
|
|
test, if provided by the target architecture, would check for
|
|
more exotic cases - most target architectures wouldn't bother
|
|
with this second case. */
|
|
if (!FRAME_CHAIN_VALID (address, next_frame))
|
|
return 0;
|
|
}
|
|
if (address == 0)
|
|
return 0;
|
|
|
|
/* Create an initially zero previous frame. */
|
|
prev = (struct frame_info *)
|
|
obstack_alloc (&frame_cache_obstack,
|
|
sizeof (struct frame_info));
|
|
memset (prev, 0, sizeof (struct frame_info));
|
|
|
|
/* Link it in. */
|
|
next_frame->prev = prev;
|
|
prev->next = next_frame;
|
|
prev->frame = address;
|
|
prev->level = next_frame->level + 1;
|
|
|
|
/* This change should not be needed, FIXME! We should determine
|
|
whether any targets *need* INIT_FRAME_PC to happen after
|
|
INIT_EXTRA_FRAME_INFO and come up with a simple way to express
|
|
what goes on here.
|
|
|
|
INIT_EXTRA_FRAME_INFO is called from two places: create_new_frame
|
|
(where the PC is already set up) and here (where it isn't).
|
|
INIT_FRAME_PC is only called from here, always after
|
|
INIT_EXTRA_FRAME_INFO.
|
|
|
|
The catch is the MIPS, where INIT_EXTRA_FRAME_INFO requires the
|
|
PC value (which hasn't been set yet). Some other machines appear
|
|
to require INIT_EXTRA_FRAME_INFO before they can do
|
|
INIT_FRAME_PC. Phoo.
|
|
|
|
We shouldn't need INIT_FRAME_PC_FIRST to add more complication to
|
|
an already overcomplicated part of GDB. gnu@cygnus.com, 15Sep92.
|
|
|
|
Assuming that some machines need INIT_FRAME_PC after
|
|
INIT_EXTRA_FRAME_INFO, one possible scheme:
|
|
|
|
SETUP_INNERMOST_FRAME(): Default version is just create_new_frame
|
|
(read_fp ()), read_pc ()). Machines with extra frame info would
|
|
do that (or the local equivalent) and then set the extra fields.
|
|
|
|
SETUP_ARBITRARY_FRAME(argc, argv): Only change here is that
|
|
create_new_frame would no longer init extra frame info;
|
|
SETUP_ARBITRARY_FRAME would have to do that.
|
|
|
|
INIT_PREV_FRAME(fromleaf, prev) Replace INIT_EXTRA_FRAME_INFO and
|
|
INIT_FRAME_PC. This should also return a flag saying whether to
|
|
keep the new frame, or whether to discard it, because on some
|
|
machines (e.g. mips) it is really awkward to have
|
|
FRAME_CHAIN_VALID called *before* INIT_EXTRA_FRAME_INFO (there is
|
|
no good way to get information deduced in FRAME_CHAIN_VALID into
|
|
the extra fields of the new frame). std_frame_pc(fromleaf, prev)
|
|
|
|
This is the default setting for INIT_PREV_FRAME. It just does
|
|
what the default INIT_FRAME_PC does. Some machines will call it
|
|
from INIT_PREV_FRAME (either at the beginning, the end, or in the
|
|
middle). Some machines won't use it.
|
|
|
|
kingdon@cygnus.com, 13Apr93, 31Jan94, 14Dec94. */
|
|
|
|
/* NOTE: cagney/2002-11-09: Just ignore the above! There is no
|
|
reason for things to be this complicated.
|
|
|
|
The trick is to assume that there is always a frame. Instead of
|
|
special casing the inner-most frame, create fake frame
|
|
(containing the hardware registers) that is inner to the
|
|
user-visible inner-most frame (...) and then unwind from that.
|
|
That way architecture code can use use the standard
|
|
frame_XX_unwind() functions and not differentiate between the
|
|
inner most and any other case.
|
|
|
|
Since there is always a frame to unwind from, there is always
|
|
somewhere (NEXT_FRAME) to store all the info needed to construct
|
|
a new (previous) frame without having to first create it. This
|
|
means that the convolution below - needing to carefully order a
|
|
frame's initialization - isn't needed.
|
|
|
|
The irony here though, is that FRAME_CHAIN(), at least for a more
|
|
up-to-date architecture, always calls FRAME_SAVED_PC(), and
|
|
FRAME_SAVED_PC() computes the PC but without first needing the
|
|
frame! Instead of the convolution below, we could have simply
|
|
called FRAME_SAVED_PC() and been done with it! Note that
|
|
FRAME_SAVED_PC() is being superseed by frame_pc_unwind() and that
|
|
function does have somewhere to cache that PC value. */
|
|
|
|
INIT_FRAME_PC_FIRST (fromleaf, prev);
|
|
|
|
if (INIT_EXTRA_FRAME_INFO_P ())
|
|
INIT_EXTRA_FRAME_INFO (fromleaf, prev);
|
|
|
|
/* This entry is in the frame queue now, which is good since
|
|
FRAME_SAVED_PC may use that queue to figure out its value (see
|
|
tm-sparc.h). We want the pc saved in the inferior frame. */
|
|
INIT_FRAME_PC (fromleaf, prev);
|
|
|
|
/* If ->frame and ->pc are unchanged, we are in the process of
|
|
getting ourselves into an infinite backtrace. Some architectures
|
|
check this in FRAME_CHAIN or thereabouts, but it seems like there
|
|
is no reason this can't be an architecture-independent check. */
|
|
if (prev->frame == next_frame->frame
|
|
&& prev->pc == next_frame->pc)
|
|
{
|
|
next_frame->prev = NULL;
|
|
obstack_free (&frame_cache_obstack, prev);
|
|
return NULL;
|
|
}
|
|
|
|
/* Initialize the code used to unwind the frame PREV based on the PC
|
|
(and probably other architectural information). The PC lets you
|
|
check things like the debug info at that point (dwarf2cfi?) and
|
|
use that to decide how the frame should be unwound. */
|
|
set_unwind_by_pc (prev->pc, prev->frame, &prev->register_unwind,
|
|
&prev->pc_unwind);
|
|
|
|
find_pc_partial_function (prev->pc, &name,
|
|
(CORE_ADDR *) NULL, (CORE_ADDR *) NULL);
|
|
if (PC_IN_SIGTRAMP (prev->pc, name))
|
|
prev->signal_handler_caller = 1;
|
|
|
|
return prev;
|
|
}
|
|
|
|
CORE_ADDR
|
|
get_frame_pc (struct frame_info *frame)
|
|
{
|
|
return frame->pc;
|
|
}
|
|
|
|
#ifdef FRAME_FIND_SAVED_REGS
|
|
/* XXX - deprecated. This is a compatibility function for targets
|
|
that do not yet implement FRAME_INIT_SAVED_REGS. */
|
|
/* Find the addresses in which registers are saved in FRAME. */
|
|
|
|
void
|
|
get_frame_saved_regs (struct frame_info *frame,
|
|
struct frame_saved_regs *saved_regs_addr)
|
|
{
|
|
if (frame->saved_regs == NULL)
|
|
{
|
|
frame->saved_regs = (CORE_ADDR *)
|
|
frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
|
|
}
|
|
if (saved_regs_addr == NULL)
|
|
{
|
|
struct frame_saved_regs saved_regs;
|
|
FRAME_FIND_SAVED_REGS (frame, saved_regs);
|
|
memcpy (frame->saved_regs, &saved_regs, SIZEOF_FRAME_SAVED_REGS);
|
|
}
|
|
else
|
|
{
|
|
FRAME_FIND_SAVED_REGS (frame, *saved_regs_addr);
|
|
memcpy (frame->saved_regs, saved_regs_addr, SIZEOF_FRAME_SAVED_REGS);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
void
|
|
_initialize_frame (void)
|
|
{
|
|
obstack_init (&frame_cache_obstack);
|
|
}
|