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/* Cache and manage frames for GDB, the GNU debugger.
Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000,
2001, 2002 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "defs.h"
#include "frame.h"
#include "target.h"
#include "value.h"
#include "inferior.h" /* for inferior_ptid */
#include "regcache.h"
#include "gdb_assert.h"
/* Return a frame uniq ID that can be used to, later re-find the
frame. */
void
get_frame_id (struct frame_info *fi, struct frame_id *id)
{
if (fi == NULL)
{
id->base = 0;
id->pc = 0;
}
else
{
id->base = FRAME_FP (fi);
id->pc = fi->pc;
}
}
struct frame_info *
frame_find_by_id (struct frame_id id)
{
struct frame_info *frame;
/* ZERO denotes the null frame, let the caller decide what to do
about it. Should it instead return get_current_frame()? */
if (id.base == 0 && id.pc == 0)
return NULL;
for (frame = get_current_frame ();
frame != NULL;
frame = get_prev_frame (frame))
{
if (INNER_THAN (FRAME_FP (frame), id.base))
/* ``inner/current < frame < id.base''. Keep looking along
the frame chain. */
continue;
if (INNER_THAN (id.base, FRAME_FP (frame)))
/* ``inner/current < id.base < frame''. Oops, gone past it.
Just give up. */
return NULL;
/* FIXME: cagney/2002-04-21: This isn't sufficient. It should
use id.pc to check that the two frames belong to the same
function. Otherwise we'll do things like match dummy frames
or mis-match frameless functions. However, until someone
notices, stick with the existing behavour. */
return frame;
}
return NULL;
}
/* FIND_SAVED_REGISTER ()
Return the address in which frame FRAME's value of register REGNUM
has been saved in memory. Or return zero if it has not been saved.
If REGNUM specifies the SP, the value we return is actually
the SP value, not an address where it was saved. */
CORE_ADDR
find_saved_register (struct frame_info *frame, int regnum)
{
register struct frame_info *frame1 = NULL;
register CORE_ADDR addr = 0;
if (frame == NULL) /* No regs saved if want current frame */
return 0;
/* Note that the following loop assumes that registers used in
frame x will be saved only in the frame that x calls and frames
interior to it. */
while (1)
{
QUIT;
frame1 = get_next_frame (frame);
if (frame1 == 0)
break;
frame = frame1;
FRAME_INIT_SAVED_REGS (frame1);
if (frame1->saved_regs[regnum])
{
addr = frame1->saved_regs[regnum];
break;
}
}
return addr;
}
void
frame_register_unwind (struct frame_info *frame, int regnum,
int *optimizedp, enum lval_type *lvalp,
CORE_ADDR *addrp, int *realnump, void *bufferp)
{
struct frame_unwind_cache *cache;
/* Require all but BUFFERP to be valid. A NULL BUFFERP indicates
that the value proper does not need to be fetched. */
gdb_assert (optimizedp != NULL);
gdb_assert (lvalp != NULL);
gdb_assert (addrp != NULL);
gdb_assert (realnump != NULL);
/* gdb_assert (bufferp != NULL); */
/* NOTE: cagney/2002-04-14: It would be nice if, instead of a
special case, there was always an inner frame dedicated to the
hardware registers. Unfortunatly, there is too much unwind code
around that looks up/down the frame chain while making the
assumption that each frame level is using the same unwind code. */
if (frame == NULL)
{
/* We're in the inner-most frame, get the value direct from the
register cache. */
*optimizedp = 0;
*lvalp = lval_register;
*addrp = 0;
/* Should this code test ``register_cached (regnum) < 0'' and do
something like set realnum to -1 when the register isn't
available? */
*realnump = regnum;
if (bufferp)
read_register_gen (regnum, bufferp);
return;
}
/* Ask this frame to unwind its register. */
frame->register_unwind (frame, &frame->register_unwind_cache, regnum,
optimizedp, lvalp, addrp, realnump, bufferp);
}
void
generic_unwind_get_saved_register (char *raw_buffer,
int *optimizedp,
CORE_ADDR *addrp,
struct frame_info *frame,
int regnum,
enum lval_type *lvalp)
{
int optimizedx;
CORE_ADDR addrx;
int realnumx;
enum lval_type lvalx;
if (!target_has_registers)
error ("No registers.");
/* Keep things simple, ensure that all the pointers (except valuep)
are non NULL. */
if (optimizedp == NULL)
optimizedp = &optimizedx;
if (lvalp == NULL)
lvalp = &lvalx;
if (addrp == NULL)
addrp = &addrx;
/* Reached the the bottom (youngest, inner most) of the frame chain
(youngest, inner most) frame, go direct to the hardware register
cache (do not pass go, do not try to cache the value, ...). The
unwound value would have been cached in frame->next but that
doesn't exist. This doesn't matter as the hardware register
cache is stopping any unnecessary accesses to the target. */
/* NOTE: cagney/2002-04-14: It would be nice if, instead of a
special case, there was always an inner frame dedicated to the
hardware registers. Unfortunatly, there is too much unwind code
around that looks up/down the frame chain while making the
assumption that each frame level is using the same unwind code. */
if (frame == NULL)
frame_register_unwind (NULL, regnum, optimizedp, lvalp, addrp, &realnumx,
raw_buffer);
else
frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp,
&realnumx, raw_buffer);
}
void
get_saved_register (char *raw_buffer,
int *optimized,
CORE_ADDR *addrp,
struct frame_info *frame,
int regnum,
enum lval_type *lval)
{
GET_SAVED_REGISTER (raw_buffer, optimized, addrp, frame, regnum, lval);
}
/* frame_register_read ()
Find and return the value of REGNUM for the specified stack frame.
The number of bytes copied is REGISTER_RAW_SIZE (REGNUM).
Returns 0 if the register value could not be found. */
int
frame_register_read (struct frame_info *frame, int regnum, void *myaddr)
{
int optim;
get_saved_register (myaddr, &optim, (CORE_ADDR *) NULL, frame,
regnum, (enum lval_type *) NULL);
/* FIXME: cagney/2002-05-15: This test, is just bogus.
It indicates that the target failed to supply a value for a
register because it was "not available" at this time. Problem
is, the target still has the register and so get saved_register()
may be returning a value saved on the stack. */
if (register_cached (regnum) < 0)
return 0; /* register value not available */
return !optim;
}
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