Files
binutils-gdb/gdb/sentinel-frame.c
Guinevere Larsen 1239e7cf37 gdb: Migrate frame unwinders to use C++ classes
Frame unwinders have historically been a structure populated with
callback pointers, so that architectures (or other specific unwinders)
could install their own way to handle the inferior. However, since
moving to C++, we could use polymorphism to get the same functionality
in a more readable way. Polymorphism also makes it simpler to add new
functionality to all frame unwinders, since all that's required is
adding it to the base class.

As part of the changes to add support to disabling frame unwinders,
this commit makes the first baby step in  using polymorphism for the
frame unwinders, by making frame_unwind a virtual class, and adds a
couple of new classes. The main class added is frame_unwind_legacy,
which works the same as the previous structs, using function pointers
as callbacks. This class was added to allow the transition to happen
piecemeal. New unwinders should instead follow the lead of the other
classes implemented.

2 of the others, frame_unwind_python and frame_unwind_trampoline, were added
because it seemed simpler at the moment to do that instead of reworking
the dynamic allocation to work with the legacy class, and can be used as
an example to future implementations.

Finally, the cygwin unwinder was converted to a class since it was most
of the way there already.

Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>
2025-01-17 11:49:16 -03:00

93 lines
2.5 KiB
C

/* Code dealing with register stack frames, for GDB, the GNU debugger.
Copyright (C) 1986-2024 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 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 "regcache.h"
#include "sentinel-frame.h"
#include "inferior.h"
#include "frame-unwind.h"
struct frame_unwind_cache
{
struct regcache *regcache;
};
void *
sentinel_frame_cache (struct regcache *regcache)
{
struct frame_unwind_cache *cache =
FRAME_OBSTACK_ZALLOC (struct frame_unwind_cache);
cache->regcache = regcache;
return cache;
}
/* Here the register value is taken direct from the register cache. */
static struct value *
sentinel_frame_prev_register (const frame_info_ptr &this_frame,
void **this_prologue_cache,
int regnum)
{
struct frame_unwind_cache *cache
= (struct frame_unwind_cache *) *this_prologue_cache;
struct value *value;
frame_id this_frame_id = get_frame_id (this_frame);
gdb_assert (is_sentinel_frame_id (this_frame_id));
value = cache->regcache->cooked_read_value (regnum);
return value;
}
static void
sentinel_frame_this_id (const frame_info_ptr &this_frame,
void **this_prologue_cache,
struct frame_id *this_id)
{
/* The sentinel frame is used as a starting point for creating the
previous (inner most) frame. That frame's THIS_ID method will be
called to determine the inner most frame's ID. Not this one. */
internal_error (_("sentinel_frame_this_id called"));
}
static struct gdbarch *
sentinel_frame_prev_arch (const frame_info_ptr &this_frame,
void **this_prologue_cache)
{
struct frame_unwind_cache *cache
= (struct frame_unwind_cache *) *this_prologue_cache;
return cache->regcache->arch ();
}
const struct frame_unwind_legacy sentinel_frame_unwind (
"sentinel",
SENTINEL_FRAME,
FRAME_UNWIND_GDB,
default_frame_unwind_stop_reason,
sentinel_frame_this_id,
sentinel_frame_prev_register,
NULL,
NULL,
NULL,
sentinel_frame_prev_arch
);