binutils-gdb/gdb/sh-linux-tdep.c
Simon Marchi 8480a37e14 gdb: pass frames as const frame_info_ptr &
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>
2024-02-20 10:42:25 -05:00

217 lines
6.4 KiB
C

/* Target-dependent code for GNU/Linux Super-H.
Copyright (C) 2005-2024 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 "defs.h"
#include "osabi.h"
#include "solib-svr4.h"
#include "symtab.h"
#include "trad-frame.h"
#include "tramp-frame.h"
#include "glibc-tdep.h"
#include "sh-tdep.h"
#include "linux-tdep.h"
#include "gdbarch.h"
#define REGSx16(base) \
{(base), 0}, \
{(base) + 1, 4}, \
{(base) + 2, 8}, \
{(base) + 3, 12}, \
{(base) + 4, 16}, \
{(base) + 5, 20}, \
{(base) + 6, 24}, \
{(base) + 7, 28}, \
{(base) + 8, 32}, \
{(base) + 9, 36}, \
{(base) + 10, 40}, \
{(base) + 11, 44}, \
{(base) + 12, 48}, \
{(base) + 13, 52}, \
{(base) + 14, 56}, \
{(base) + 15, 60}
/* Describe the contents of the .reg section of the core file. */
static const struct sh_corefile_regmap gregs_table[] =
{
REGSx16 (R0_REGNUM),
{PC_REGNUM, 64},
{PR_REGNUM, 68},
{SR_REGNUM, 72},
{GBR_REGNUM, 76},
{MACH_REGNUM, 80},
{MACL_REGNUM, 84},
{-1 /* Terminator. */, 0}
};
/* Describe the contents of the .reg2 section of the core file. */
static const struct sh_corefile_regmap fpregs_table[] =
{
REGSx16 (FR0_REGNUM),
/* REGSx16 xfp_regs omitted. */
{FPSCR_REGNUM, 128},
{FPUL_REGNUM, 132},
{-1 /* Terminator. */, 0}
};
/* SH signal handler frame support. */
static void
sh_linux_sigtramp_cache (const frame_info_ptr &this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func, int regs_offset)
{
int i;
struct gdbarch *gdbarch = get_frame_arch (this_frame);
CORE_ADDR base = get_frame_register_unsigned (this_frame,
gdbarch_sp_regnum (gdbarch));
CORE_ADDR regs = base + regs_offset;
for (i = 0; i < 18; i++)
trad_frame_set_reg_addr (this_cache, i, regs + i * 4);
trad_frame_set_reg_addr (this_cache, SR_REGNUM, regs + 18 * 4);
trad_frame_set_reg_addr (this_cache, GBR_REGNUM, regs + 19 * 4);
trad_frame_set_reg_addr (this_cache, MACH_REGNUM, regs + 20 * 4);
trad_frame_set_reg_addr (this_cache, MACL_REGNUM, regs + 21 * 4);
/* Restore FP state if we have an FPU. */
if (gdbarch_fp0_regnum (gdbarch) != -1)
{
CORE_ADDR fpregs = regs + 22 * 4;
for (i = FR0_REGNUM; i <= FP_LAST_REGNUM; i++)
trad_frame_set_reg_addr (this_cache, i, fpregs + i * 4);
trad_frame_set_reg_addr (this_cache, FPSCR_REGNUM, fpregs + 32 * 4);
trad_frame_set_reg_addr (this_cache, FPUL_REGNUM, fpregs + 33 * 4);
}
/* Save a frame ID. */
trad_frame_set_id (this_cache, frame_id_build (base, func));
}
/* Implement struct tramp_frame "init" callbacks for signal
trampolines on 32-bit SH. */
static void
sh_linux_sigreturn_init (const struct tramp_frame *self,
const frame_info_ptr &this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
/* SH 32-bit sigframe: sigcontext at start of sigframe,
registers start after a single 'oldmask' word. */
sh_linux_sigtramp_cache (this_frame, this_cache, func, 4);
}
static void
sh_linux_rt_sigreturn_init (const struct tramp_frame *self,
const frame_info_ptr &this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
/* SH 32-bit rt_sigframe: starts with a siginfo (128 bytes), then
we can find sigcontext embedded within a ucontext (offset 20 bytes).
Then registers start after a single 'oldmask' word. */
sh_linux_sigtramp_cache (this_frame, this_cache, func,
128 /* sizeof (struct siginfo) */
+ 20 /* offsetof (struct ucontext, uc_mcontext) */
+ 4 /* oldmask word at start of sigcontext */);
}
/* Instruction patterns. */
#define SH_MOVW 0x9305
#define SH_TRAP 0xc300
#define SH_OR_R0_R0 0x200b
/* SH sigreturn syscall numbers. */
#define SH_NR_SIGRETURN 0x0077
#define SH_NR_RT_SIGRETURN 0x00ad
static struct tramp_frame sh_linux_sigreturn_tramp_frame = {
SIGTRAMP_FRAME,
2,
{
{ SH_MOVW, 0xffff },
{ SH_TRAP, 0xff00 }, /* #imm argument part filtered out. */
{ SH_OR_R0_R0, 0xffff },
{ SH_OR_R0_R0, 0xffff },
{ SH_OR_R0_R0, 0xffff },
{ SH_OR_R0_R0, 0xffff },
{ SH_OR_R0_R0, 0xffff },
{ SH_NR_SIGRETURN, 0xffff },
{ TRAMP_SENTINEL_INSN }
},
sh_linux_sigreturn_init
};
static struct tramp_frame sh_linux_rt_sigreturn_tramp_frame = {
SIGTRAMP_FRAME,
2,
{
{ SH_MOVW, 0xffff },
{ SH_TRAP, 0xff00 }, /* #imm argument part filtered out. */
{ SH_OR_R0_R0, 0xffff },
{ SH_OR_R0_R0, 0xffff },
{ SH_OR_R0_R0, 0xffff },
{ SH_OR_R0_R0, 0xffff },
{ SH_OR_R0_R0, 0xffff },
{ SH_NR_RT_SIGRETURN, 0xffff },
{ TRAMP_SENTINEL_INSN }
},
sh_linux_rt_sigreturn_init
};
static void
sh_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
linux_init_abi (info, gdbarch, 0);
/* GNU/Linux uses SVR4-style shared libraries. */
set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
set_solib_svr4_fetch_link_map_offsets
(gdbarch, linux_ilp32_fetch_link_map_offsets);
set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
set_gdbarch_fetch_tls_load_module_address (gdbarch,
svr4_fetch_objfile_link_map);
sh_gdbarch_tdep *tdep = gdbarch_tdep<sh_gdbarch_tdep> (gdbarch);
/* Remember regset characteristics. The sizes should match
elf_gregset_t and elf_fpregset_t from Linux. */
tdep->core_gregmap = (struct sh_corefile_regmap *) gregs_table;
tdep->sizeof_gregset = 92;
tdep->core_fpregmap = (struct sh_corefile_regmap *) fpregs_table;
tdep->sizeof_fpregset = 136;
tramp_frame_prepend_unwinder (gdbarch, &sh_linux_sigreturn_tramp_frame);
tramp_frame_prepend_unwinder (gdbarch, &sh_linux_rt_sigreturn_tramp_frame);
}
void _initialize_sh_linux_tdep ();
void
_initialize_sh_linux_tdep ()
{
gdbarch_register_osabi (bfd_arch_sh, 0, GDB_OSABI_LINUX, sh_linux_init_abi);
}