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8480a37e14
We currently pass frames to function by value, as `frame_info_ptr`.
This is somewhat expensive:
- the size of `frame_info_ptr` is 64 bytes, which is a bit big to pass
by value
- the constructors and destructor link/unlink the object in the global
`frame_info_ptr::frame_list` list. This is an `intrusive_list`, so
it's not so bad: it's just assigning a few points, there's no memory
allocation as if it was `std::list`, but still it's useless to do
that over and over.
As suggested by Tom Tromey, change many function signatures to accept
`const frame_info_ptr &` instead of `frame_info_ptr`.
Some functions reassign their `frame_info_ptr` parameter, like:
void
the_func (frame_info_ptr frame)
{
for (; frame != nullptr; frame = get_prev_frame (frame))
{
...
}
}
I wondered what to do about them, do I leave them as-is or change them
(and need to introduce a separate local variable that can be
re-assigned). I opted for the later for consistency. It might not be
clear why some functions take `const frame_info_ptr &` while others take
`frame_info_ptr`. Also, if a function took a `frame_info_ptr` because
it did re-assign its parameter, I doubt that we would think to change it
to `const frame_info_ptr &` should the implementation change such that
it doesn't need to take `frame_info_ptr` anymore. It seems better to
have a simple rule and apply it everywhere.
Change-Id: I59d10addef687d157f82ccf4d54f5dde9a963fd0
Approved-By: Andrew Burgess <aburgess@redhat.com>
125 lines
3.6 KiB
C
125 lines
3.6 KiB
C
/* Target-dependent code for OpenBSD/arm.
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Copyright (C) 2006-2024 Free Software Foundation, Inc.
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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 "osabi.h"
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#include "trad-frame.h"
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#include "tramp-frame.h"
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#include "obsd-tdep.h"
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#include "arm-tdep.h"
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#include "solib-svr4.h"
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/* Signal trampolines. */
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static void
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armobsd_sigframe_init (const struct tramp_frame *self,
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const frame_info_ptr &this_frame,
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struct trad_frame_cache *cache,
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CORE_ADDR func)
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{
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CORE_ADDR sp, sigcontext_addr, addr;
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int regnum;
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/* We find the appropriate instance of `struct sigcontext' at a
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fixed offset in the signal frame. */
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sp = get_frame_register_signed (this_frame, ARM_SP_REGNUM);
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sigcontext_addr = sp + 16;
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/* PC. */
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trad_frame_set_reg_addr (cache, ARM_PC_REGNUM, sigcontext_addr + 76);
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/* GPRs. */
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for (regnum = ARM_A1_REGNUM, addr = sigcontext_addr + 12;
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regnum <= ARM_LR_REGNUM; regnum++, addr += 4)
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trad_frame_set_reg_addr (cache, regnum, addr);
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trad_frame_set_id (cache, frame_id_build (sp, func));
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}
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static const struct tramp_frame armobsd_sigframe =
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{
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SIGTRAMP_FRAME,
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4,
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{
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{ 0xe28d0010, ULONGEST_MAX }, /* add r0, sp, #16 */
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{ 0xef000067, ULONGEST_MAX }, /* swi SYS_sigreturn */
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{ 0xef000001, ULONGEST_MAX }, /* swi SYS_exit */
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{ 0xeafffffc, ULONGEST_MAX }, /* b . - 8 */
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{ TRAMP_SENTINEL_INSN, ULONGEST_MAX }
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},
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armobsd_sigframe_init
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};
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/* Override default thumb breakpoints. */
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static const gdb_byte arm_obsd_thumb_le_breakpoint[] = {0xfe, 0xdf};
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static const gdb_byte arm_obsd_thumb_be_breakpoint[] = {0xdf, 0xfe};
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static void
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armobsd_init_abi (struct gdbarch_info info,
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struct gdbarch *gdbarch)
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{
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arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
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if (tdep->fp_model == ARM_FLOAT_AUTO)
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tdep->fp_model = ARM_FLOAT_SOFT_VFP;
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tramp_frame_prepend_unwinder (gdbarch, &armobsd_sigframe);
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/* OpenBSD/arm uses SVR4-style shared libraries. */
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set_solib_svr4_fetch_link_map_offsets
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(gdbarch, svr4_ilp32_fetch_link_map_offsets);
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set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
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tdep->jb_pc = 24;
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tdep->jb_elt_size = 4;
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set_gdbarch_iterate_over_regset_sections
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(gdbarch, armbsd_iterate_over_regset_sections);
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/* OpenBSD/arm uses -fpcc-struct-return by default. */
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tdep->struct_return = pcc_struct_return;
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/* Single stepping. */
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set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
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/* Breakpoints. */
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switch (info.byte_order)
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{
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case BFD_ENDIAN_BIG:
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tdep->thumb_breakpoint = arm_obsd_thumb_be_breakpoint;
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tdep->thumb_breakpoint_size = sizeof (arm_obsd_thumb_be_breakpoint);
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break;
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case BFD_ENDIAN_LITTLE:
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tdep->thumb_breakpoint = arm_obsd_thumb_le_breakpoint;
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tdep->thumb_breakpoint_size = sizeof (arm_obsd_thumb_le_breakpoint);
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break;
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}
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}
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void _initialize_armobsd_tdep ();
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void
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_initialize_armobsd_tdep ()
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{
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gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_OPENBSD,
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armobsd_init_abi);
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}
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