binutils-gdb/gdb/frame.c

172 lines
5.1 KiB
C

/* Cache and manage the values of registers 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"
/* 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 this next routine assumes that registers used in
frame x will be saved only in the frame that x calls and
frames interior to it. This is not true on the sparc, but the
above macro takes care of it, so we should be all right. */
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];
}
return addr;
}
/* DEFAULT_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). 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). Set *ADDRP to the address, either in memory
on as a REGISTER_BYTE offset into the registers array.
Note that this implementation never sets *LVAL to not_lval. But
it can be replaced by defining GET_SAVED_REGISTER and supplying
your own.
The argument RAW_BUFFER must point to aligned memory. */
static void
default_get_saved_register (char *raw_buffer,
int *optimized,
CORE_ADDR *addrp,
struct frame_info *frame,
int regnum,
enum lval_type *lval)
{
CORE_ADDR addr;
if (!target_has_registers)
error ("No registers.");
/* Normal systems don't optimize out things with register numbers. */
if (optimized != NULL)
*optimized = 0;
addr = find_saved_register (frame, regnum);
if (addr != 0)
{
if (lval != NULL)
*lval = lval_memory;
if (regnum == SP_REGNUM)
{
if (raw_buffer != NULL)
{
/* Put it back in target format. */
store_address (raw_buffer, REGISTER_RAW_SIZE (regnum),
(LONGEST) addr);
}
if (addrp != NULL)
*addrp = 0;
return;
}
if (raw_buffer != NULL)
target_read_memory (addr, raw_buffer, REGISTER_RAW_SIZE (regnum));
}
else
{
if (lval != NULL)
*lval = lval_register;
addr = REGISTER_BYTE (regnum);
if (raw_buffer != NULL)
read_register_gen (regnum, raw_buffer);
}
if (addrp != NULL)
*addrp = addr;
}
#if !defined (GET_SAVED_REGISTER)
#define GET_SAVED_REGISTER(raw_buffer, optimized, addrp, frame, regnum, lval) \
default_get_saved_register(raw_buffer, optimized, addrp, frame, regnum, lval)
#endif
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;
}