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a7952927db
Some functions related to the handling of registers in frames accept "this frame", for which we want to read or write the register values, while other functions accept "the next frame", which is the frame next to that. The later is needed because we sometimes need to read register values for a frame that does not exist yet (usually when trying to unwind that frame-to-be). value_of_register and value_of_register_lazy both take "this frame", even if what they ultimately want internally is "the next frame". This is annoying if you are in a spot that currently has "the next frame" and need to call one of these functions (which happens later in this series). You need to get the previous frame only for those functions to get the next frame again. This is more manipulations, more chances of mistake. I propose to change these functions (and a few more functions in the subsequent patches) to operate on "the next frame". Things become a bit less awkward when all these functions agree on which frame they take. So, in this patch, change value_of_register_lazy and value_of_register to take "the next frame" instead of "this frame". This adds a lot of get_next_frame_sentinel_okay, but if we convert the user registers API to also use "the next frame" instead of "this frame", it will get simple again. Change-Id: Iaa24815e648fbe5ae3c214c738758890a91819cd Reviewed-By: John Baldwin <jhb@FreeBSD.org>
109 lines
3.8 KiB
C
109 lines
3.8 KiB
C
/* Builtin frame register, for GDB, the GNU debugger.
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Copyright (C) 2002-2023 Free Software Foundation, Inc.
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Contributed by Red Hat.
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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 3 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, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "user-regs.h"
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#include "frame.h"
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#include "gdbtypes.h"
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#include "value.h"
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#include "gdbarch.h"
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static struct value *
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value_of_builtin_frame_fp_reg (frame_info_ptr frame, const void *baton)
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{
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struct gdbarch *gdbarch = get_frame_arch (frame);
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if (gdbarch_deprecated_fp_regnum (gdbarch) >= 0)
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/* NOTE: cagney/2003-04-24: Since the mere presence of "fp" in the
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register name table overrides this built-in $fp register, there
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is no real reason for this gdbarch_deprecated_fp_regnum trickery here.
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An architecture wanting to implement "$fp" as alias for a raw
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register can do so by adding "fp" to register name table (mind
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you, doing this is probably a dangerous thing). */
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return value_of_register (gdbarch_deprecated_fp_regnum (gdbarch),
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get_next_frame_sentinel_okay (frame));
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else
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{
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struct type *data_ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
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struct value *val = value::allocate (data_ptr_type);
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gdb_byte *buf = val->contents_raw ().data ();
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gdbarch_address_to_pointer (gdbarch, data_ptr_type,
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buf, get_frame_base_address (frame));
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return val;
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}
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}
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static struct value *
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value_of_builtin_frame_pc_reg (frame_info_ptr frame, const void *baton)
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{
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struct gdbarch *gdbarch = get_frame_arch (frame);
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if (gdbarch_pc_regnum (gdbarch) >= 0)
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return value_of_register (gdbarch_pc_regnum (gdbarch),
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get_next_frame_sentinel_okay (frame));
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else
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{
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struct type *func_ptr_type = builtin_type (gdbarch)->builtin_func_ptr;
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struct value *val = value::allocate (func_ptr_type);
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gdb_byte *buf = val->contents_raw ().data ();
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gdbarch_address_to_pointer (gdbarch, func_ptr_type,
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buf, get_frame_pc (frame));
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return val;
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}
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}
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static struct value *
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value_of_builtin_frame_sp_reg (frame_info_ptr frame, const void *baton)
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{
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struct gdbarch *gdbarch = get_frame_arch (frame);
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if (gdbarch_sp_regnum (gdbarch) >= 0)
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return value_of_register (gdbarch_sp_regnum (gdbarch),
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get_next_frame_sentinel_okay (frame));
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error (_("Standard register ``$sp'' is not available for this target"));
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}
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static struct value *
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value_of_builtin_frame_ps_reg (frame_info_ptr frame, const void *baton)
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{
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struct gdbarch *gdbarch = get_frame_arch (frame);
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if (gdbarch_ps_regnum (gdbarch) >= 0)
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return value_of_register (gdbarch_ps_regnum (gdbarch),
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get_next_frame_sentinel_okay (frame));
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error (_("Standard register ``$ps'' is not available for this target"));
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}
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void _initialize_frame_reg ();
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void
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_initialize_frame_reg ()
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{
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/* Frame based $fp, $pc, $sp and $ps. These only come into play
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when the target does not define its own version of these
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registers. */
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user_reg_add_builtin ("fp", value_of_builtin_frame_fp_reg, NULL);
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user_reg_add_builtin ("pc", value_of_builtin_frame_pc_reg, NULL);
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user_reg_add_builtin ("sp", value_of_builtin_frame_sp_reg, NULL);
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user_reg_add_builtin ("ps", value_of_builtin_frame_ps_reg, NULL);
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}
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