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binutils-gdb/gdb/ppc-fbsd-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

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/* Target-dependent code for PowerPC systems running FreeBSD.
Copyright (C) 2013-2024 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 "arch-utils.h"
#include "frame.h"
#include "gdbcore.h"
#include "frame-unwind.h"
#include "gdbtypes.h"
#include "osabi.h"
#include "regcache.h"
#include "regset.h"
#include "symtab.h"
#include "target.h"
#include "trad-frame.h"
#include "ppc-tdep.h"
#include "ppc64-tdep.h"
#include "ppc-fbsd-tdep.h"
#include "fbsd-tdep.h"
#include "solib-svr4.h"
#include "inferior.h"
/* 32-bit regset descriptions. */
static const struct ppc_reg_offsets ppc32_fbsd_reg_offsets =
{
/* General-purpose registers. */
/* .r0_offset = */ 0,
/* .gpr_size = */ 4,
/* .xr_size = */ 4,
/* .pc_offset = */ 144,
/* .ps_offset = */ -1,
/* .cr_offset = */ 132,
/* .lr_offset = */ 128,
/* .ctr_offset = */ 140,
/* .xer_offset = */ 136,
/* .mq_offset = */ -1,
/* Floating-point registers. */
/* .f0_offset = */ 0,
/* .fpscr_offset = */ 256,
/* .fpscr_size = */ 8
};
/* 64-bit regset descriptions. */
static const struct ppc_reg_offsets ppc64_fbsd_reg_offsets =
{
/* General-purpose registers. */
/* .r0_offset = */ 0,
/* .gpr_size = */ 8,
/* .xr_size = */ 8,
/* .pc_offset = */ 288,
/* .ps_offset = */ -1,
/* .cr_offset = */ 264,
/* .lr_offset = */ 256,
/* .ctr_offset = */ 280,
/* .xer_offset = */ 272,
/* .mq_offset = */ -1,
/* Floating-point registers. */
/* .f0_offset = */ 0,
/* .fpscr_offset = */ 256,
/* .fpscr_size = */ 8
};
/* 32-bit general-purpose register set. */
static const struct regset ppc32_fbsd_gregset = {
&ppc32_fbsd_reg_offsets,
ppc_supply_gregset,
ppc_collect_gregset
};
/* 64-bit general-purpose register set. */
static const struct regset ppc64_fbsd_gregset = {
&ppc64_fbsd_reg_offsets,
ppc_supply_gregset,
ppc_collect_gregset
};
/* 32-/64-bit floating-point register set. */
static const struct regset ppc32_fbsd_fpregset = {
&ppc32_fbsd_reg_offsets,
ppc_supply_fpregset,
ppc_collect_fpregset
};
const struct regset *
ppc_fbsd_gregset (int wordsize)
{
return wordsize == 8 ? &ppc64_fbsd_gregset : &ppc32_fbsd_gregset;
}
const struct regset *
ppc_fbsd_fpregset (void)
{
return &ppc32_fbsd_fpregset;
}
/* Iterate over core file register note sections. */
static void
ppcfbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
iterate_over_regset_sections_cb *cb,
void *cb_data,
const struct regcache *regcache)
{
ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
if (tdep->wordsize == 4)
cb (".reg", 148, 148, &ppc32_fbsd_gregset, NULL, cb_data);
else
cb (".reg", 296, 296, &ppc64_fbsd_gregset, NULL, cb_data);
cb (".reg2", 264, 264, &ppc32_fbsd_fpregset, NULL, cb_data);
}
/* Default page size. */
static const int ppcfbsd_page_size = 4096;
/* Offset for sigreturn(2). */
static const int ppcfbsd_sigreturn_offset[] = {
0xc, /* FreeBSD 32-bit */
-1
};
/* Signal trampolines. */
static int
ppcfbsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
const frame_info_ptr &this_frame,
void **this_cache)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
CORE_ADDR pc = get_frame_pc (this_frame);
CORE_ADDR start_pc = (pc & ~(ppcfbsd_page_size - 1));
const int *offset;
const char *name;
/* A stack trampoline is detected if no name is associated
to the current pc and if it points inside a trampoline
sequence. */
find_pc_partial_function (pc, &name, NULL, NULL);
/* If we have a name, we have no trampoline, return. */
if (name)
return 0;
for (offset = ppcfbsd_sigreturn_offset; *offset != -1; offset++)
{
gdb_byte buf[2 * PPC_INSN_SIZE];
unsigned long insn;
if (!safe_frame_unwind_memory (this_frame, start_pc + *offset,
{buf, sizeof buf}))
continue;
/* Check for "li r0,SYS_sigreturn". */
insn = extract_unsigned_integer (buf, PPC_INSN_SIZE, byte_order);
if (insn != 0x380001a1)
continue;
/* Check for "sc". */
insn = extract_unsigned_integer (buf + PPC_INSN_SIZE,
PPC_INSN_SIZE, byte_order);
if (insn != 0x44000002)
continue;
return 1;
}
return 0;
}
static struct trad_frame_cache *
ppcfbsd_sigtramp_frame_cache (const frame_info_ptr &this_frame, void **this_cache)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
struct trad_frame_cache *cache;
CORE_ADDR addr, base, func;
gdb_byte buf[PPC_INSN_SIZE];
int i;
if (*this_cache)
return (struct trad_frame_cache *) *this_cache;
cache = trad_frame_cache_zalloc (this_frame);
*this_cache = cache;
func = get_frame_pc (this_frame);
func &= ~(ppcfbsd_page_size - 1);
if (!safe_frame_unwind_memory (this_frame, func, {buf, sizeof buf}))
return cache;
base = get_frame_register_unsigned (this_frame, gdbarch_sp_regnum (gdbarch));
addr = base + 0x10 + 2 * tdep->wordsize;
for (i = 0; i < ppc_num_gprs; i++, addr += tdep->wordsize)
{
int regnum = i + tdep->ppc_gp0_regnum;
trad_frame_set_reg_addr (cache, regnum, addr);
}
trad_frame_set_reg_addr (cache, tdep->ppc_lr_regnum, addr);
addr += tdep->wordsize;
trad_frame_set_reg_addr (cache, tdep->ppc_cr_regnum, addr);
addr += tdep->wordsize;
trad_frame_set_reg_addr (cache, tdep->ppc_xer_regnum, addr);
addr += tdep->wordsize;
trad_frame_set_reg_addr (cache, tdep->ppc_ctr_regnum, addr);
addr += tdep->wordsize;
trad_frame_set_reg_addr (cache, gdbarch_pc_regnum (gdbarch), addr);
/* SRR0? */
addr += tdep->wordsize;
/* Construct the frame ID using the function start. */
trad_frame_set_id (cache, frame_id_build (base, func));
return cache;
}
static void
ppcfbsd_sigtramp_frame_this_id (const frame_info_ptr &this_frame,
void **this_cache, struct frame_id *this_id)
{
struct trad_frame_cache *cache =
ppcfbsd_sigtramp_frame_cache (this_frame, this_cache);
trad_frame_get_id (cache, this_id);
}
static struct value *
ppcfbsd_sigtramp_frame_prev_register (const frame_info_ptr &this_frame,
void **this_cache, int regnum)
{
struct trad_frame_cache *cache =
ppcfbsd_sigtramp_frame_cache (this_frame, this_cache);
return trad_frame_get_register (cache, this_frame, regnum);
}
static const struct frame_unwind ppcfbsd_sigtramp_frame_unwind = {
"ppc freebsd sigtramp",
SIGTRAMP_FRAME,
default_frame_unwind_stop_reason,
ppcfbsd_sigtramp_frame_this_id,
ppcfbsd_sigtramp_frame_prev_register,
NULL,
ppcfbsd_sigtramp_frame_sniffer
};
static enum return_value_convention
ppcfbsd_return_value (struct gdbarch *gdbarch, struct value *function,
struct type *valtype, struct regcache *regcache,
gdb_byte *readbuf, const gdb_byte *writebuf)
{
return ppc_sysv_abi_broken_return_value (gdbarch, function, valtype,
regcache, readbuf, writebuf);
}
/* Implement the "get_thread_local_address" gdbarch method. */
static CORE_ADDR
ppcfbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
CORE_ADDR lm_addr, CORE_ADDR offset)
{
ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
int tp_offset, tp_regnum;
regcache *regcache
= get_thread_arch_regcache (current_inferior (), ptid, gdbarch);
if (tdep->wordsize == 4)
{
tp_offset = 0x7008;
tp_regnum = PPC_R0_REGNUM + 2;
}
else
{
tp_offset = 0x7010;
tp_regnum = PPC_R0_REGNUM + 13;
}
target_fetch_registers (regcache, tp_regnum);
ULONGEST tp;
if (regcache->cooked_read (tp_regnum, &tp) != REG_VALID)
error (_("Unable to fetch tcb pointer"));
/* tp points to the end of the TCB block. The first member of the
TCB is the pointer to the DTV array. */
CORE_ADDR dtv_addr = tp - tp_offset;
return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
}
static void
ppcfbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_gdbarch_tdep> (gdbarch);
/* Generic FreeBSD support. */
fbsd_init_abi (info, gdbarch);
/* FreeBSD doesn't support the 128-bit `long double' from the psABI. */
set_gdbarch_long_double_bit (gdbarch, 64);
set_gdbarch_long_double_format (gdbarch, floatformats_ieee_double);
if (tdep->wordsize == 4)
{
set_gdbarch_return_value (gdbarch, ppcfbsd_return_value);
set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
set_solib_svr4_fetch_link_map_offsets (gdbarch,
svr4_ilp32_fetch_link_map_offsets);
frame_unwind_append_unwinder (gdbarch, &ppcfbsd_sigtramp_frame_unwind);
set_gdbarch_gcore_bfd_target (gdbarch, "elf32-powerpc");
}
if (tdep->wordsize == 8)
{
set_gdbarch_convert_from_func_ptr_addr
(gdbarch, ppc64_convert_from_func_ptr_addr);
set_gdbarch_elf_make_msymbol_special (gdbarch,
ppc64_elf_make_msymbol_special);
set_gdbarch_skip_trampoline_code (gdbarch, ppc64_skip_trampoline_code);
set_solib_svr4_fetch_link_map_offsets (gdbarch,
svr4_lp64_fetch_link_map_offsets);
set_gdbarch_gcore_bfd_target (gdbarch, "elf64-powerpc");
}
set_gdbarch_iterate_over_regset_sections
(gdbarch, ppcfbsd_iterate_over_regset_sections);
set_gdbarch_fetch_tls_load_module_address (gdbarch,
svr4_fetch_objfile_link_map);
set_gdbarch_get_thread_local_address (gdbarch,
ppcfbsd_get_thread_local_address);
}
void _initialize_ppcfbsd_tdep ();
void
_initialize_ppcfbsd_tdep ()
{
gdbarch_register_osabi (bfd_arch_powerpc, bfd_mach_ppc, GDB_OSABI_FREEBSD,
ppcfbsd_init_abi);
gdbarch_register_osabi (bfd_arch_powerpc, bfd_mach_ppc64, GDB_OSABI_FREEBSD,
ppcfbsd_init_abi);
gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_FREEBSD,
ppcfbsd_init_abi);
}
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