binutils-gdb/gdb/std-regs.c
Simon Marchi 50888e42dc gdb: change functions returning value contents to use gdb::array_view
The bug fixed by this [1] patch was caused by an out-of-bounds access to
a value's content.  The code gets the value's content (just a pointer)
and then indexes it with a non-sensical index.

This made me think of changing functions that return value contents to
return array_views instead of a plain pointer.  This has the advantage
that when GDB is built with _GLIBCXX_DEBUG, accesses to the array_view
are checked, making bugs more apparent / easier to find.

This patch changes the return types of these functions, and updates
callers to call .data() on the result, meaning it's not changing
anything in practice.  Additional work will be needed (which can be done
little by little) to make callers propagate the use of array_view and
reap the benefits.

[1] https://sourceware.org/pipermail/gdb-patches/2021-September/182306.html

Change-Id: I5151f888f169e1c36abe2cbc57620110673816f3
2021-10-25 14:51:44 -04:00

106 lines
3.6 KiB
C

/* Builtin frame register, for GDB, the GNU debugger.
Copyright (C) 2002-2021 Free Software Foundation, Inc.
Contributed by Red Hat.
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 3 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, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "user-regs.h"
#include "frame.h"
#include "gdbtypes.h"
#include "value.h"
#include "gdbarch.h"
static struct value *
value_of_builtin_frame_fp_reg (struct frame_info *frame, const void *baton)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
if (gdbarch_deprecated_fp_regnum (gdbarch) >= 0)
/* NOTE: cagney/2003-04-24: Since the mere presence of "fp" in the
register name table overrides this built-in $fp register, there
is no real reason for this gdbarch_deprecated_fp_regnum trickery here.
An architecture wanting to implement "$fp" as alias for a raw
register can do so by adding "fp" to register name table (mind
you, doing this is probably a dangerous thing). */
return value_of_register (gdbarch_deprecated_fp_regnum (gdbarch),
frame);
else
{
struct type *data_ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
struct value *val = allocate_value (data_ptr_type);
gdb_byte *buf = value_contents_raw (val).data ();
gdbarch_address_to_pointer (gdbarch, data_ptr_type,
buf, get_frame_base_address (frame));
return val;
}
}
static struct value *
value_of_builtin_frame_pc_reg (struct frame_info *frame, const void *baton)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
if (gdbarch_pc_regnum (gdbarch) >= 0)
return value_of_register (gdbarch_pc_regnum (gdbarch), frame);
else
{
struct type *func_ptr_type = builtin_type (gdbarch)->builtin_func_ptr;
struct value *val = allocate_value (func_ptr_type);
gdb_byte *buf = value_contents_raw (val).data ();
gdbarch_address_to_pointer (gdbarch, func_ptr_type,
buf, get_frame_pc (frame));
return val;
}
}
static struct value *
value_of_builtin_frame_sp_reg (struct frame_info *frame, const void *baton)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
if (gdbarch_sp_regnum (gdbarch) >= 0)
return value_of_register (gdbarch_sp_regnum (gdbarch), frame);
error (_("Standard register ``$sp'' is not available for this target"));
}
static struct value *
value_of_builtin_frame_ps_reg (struct frame_info *frame, const void *baton)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
if (gdbarch_ps_regnum (gdbarch) >= 0)
return value_of_register (gdbarch_ps_regnum (gdbarch), frame);
error (_("Standard register ``$ps'' is not available for this target"));
}
void _initialize_frame_reg ();
void
_initialize_frame_reg ()
{
/* Frame based $fp, $pc, $sp and $ps. These only come into play
when the target does not define its own version of these
registers. */
user_reg_add_builtin ("fp", value_of_builtin_frame_fp_reg, NULL);
user_reg_add_builtin ("pc", value_of_builtin_frame_pc_reg, NULL);
user_reg_add_builtin ("sp", value_of_builtin_frame_sp_reg, NULL);
user_reg_add_builtin ("ps", value_of_builtin_frame_ps_reg, NULL);
}