/* Darwin support for GDB, the GNU debugger.
Copyright (C) 1997-2019 Free Software Foundation, Inc.
Contributed by Apple Computer, 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 "frame.h"
#include "inferior.h"
#include "gdbcore.h"
#include "target.h"
#include "symtab.h"
#include "regcache.h"
#include "objfiles.h"
#include "i387-tdep.h"
#include "i386-tdep.h"
#include "osabi.h"
#include "ui-out.h"
#include "i386-darwin-tdep.h"
#include "solib.h"
#include "solib-darwin.h"
#include "dwarf2-frame.h"
#include <algorithm>
/* Offsets into the struct i386_thread_state where we'll find the saved regs.
From <mach/i386/thread_status.h> and i386-tdep.h. */
int i386_darwin_thread_state_reg_offset[] =
{
0 * 4, /* EAX */
2 * 4, /* ECX */
3 * 4, /* EDX */
1 * 4, /* EBX */
7 * 4, /* ESP */
6 * 4, /* EBP */
5 * 4, /* ESI */
4 * 4, /* EDI */
10 * 4, /* EIP */
9 * 4, /* EFLAGS */
11 * 4, /* CS */
8 * 4, /* SS */
12 * 4, /* DS */
13 * 4, /* ES */
14 * 4, /* FS */
15 * 4 /* GS */
};
const int i386_darwin_thread_state_num_regs =
ARRAY_SIZE (i386_darwin_thread_state_reg_offset);
/* Assuming THIS_FRAME is a Darwin sigtramp routine, return the
address of the associated sigcontext structure. */
static CORE_ADDR
i386_darwin_sigcontext_addr (struct frame_info *this_frame)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
CORE_ADDR bp;
CORE_ADDR si;
gdb_byte buf[4];
get_frame_register (this_frame, I386_EBP_REGNUM, buf);
bp = extract_unsigned_integer (buf, 4, byte_order);
/* A pointer to the ucontext is passed as the fourth argument
to the signal handler. */
read_memory (bp + 24, buf, 4);
si = extract_unsigned_integer (buf, 4, byte_order);
/* The pointer to mcontext is at offset 28. */
read_memory (si + 28, buf, 4);
/* First register (eax) is at offset 12. */
return extract_unsigned_integer (buf, 4, byte_order) + 12;
}
/* Return true if the PC of THIS_FRAME is in a signal trampoline which
may have DWARF-2 CFI.
On Darwin, signal trampolines have DWARF-2 CFI but it has only one FDE
that covers only the indirect call to the user handler.
Without this function, the frame is recognized as a normal frame which is
not expected. */
int
darwin_dwarf_signal_frame_p (struct gdbarch *gdbarch,
struct frame_info *this_frame)
{
return i386_sigtramp_p (this_frame);
}
/* Check wether TYPE is a 128-bit vector (__m128, __m128d or __m128i). */
static int
i386_m128_p (struct type *type)
{
return (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type)
&& TYPE_LENGTH (type) == 16);
}
/* Return the alignment for TYPE when passed as an argument. */
static int
i386_darwin_arg_type_alignment (struct type *type)
{
type = check_typedef (type);
/* According to Mac OS X ABI document (passing arguments):
6. The caller places 64-bit vectors (__m64) on the parameter area,
aligned to 8-byte boundaries.
7. [...] The caller aligns 128-bit vectors in the parameter area to
16-byte boundaries. */
if (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type))
return TYPE_LENGTH (type);
/* 4. The caller places all the fields of structures (or unions) with no
vector elements in the parameter area. These structures are 4-byte
aligned.
5. The caller places structures with vector elements on the stack,
16-byte aligned. */
if (TYPE_CODE (type) == TYPE_CODE_STRUCT
|| TYPE_CODE (type) == TYPE_CODE_UNION)
{
int i;
int res = 4;
for (i = 0; i < TYPE_NFIELDS (type); i++)
{
int align
= i386_darwin_arg_type_alignment (TYPE_FIELD_TYPE (type, i));
res = std::max (res, align);
}
return res;
}
/* 2. The caller aligns nonvector arguments to 4-byte boundaries. */
return 4;
}
static CORE_ADDR
i386_darwin_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
struct regcache *regcache, CORE_ADDR bp_addr,
int nargs, struct value **args, CORE_ADDR sp,
function_call_return_method return_method,
CORE_ADDR struct_addr)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
gdb_byte buf[4];
int i;
int write_pass;
/* Determine the total space required for arguments and struct
return address in a first pass, then push arguments in a second pass. */
for (write_pass = 0; write_pass < 2; write_pass++)
{
int args_space = 0;
int num_m128 = 0;
if (return_method == return_method_struct)
{
if (write_pass)
{
/* Push value address. */
store_unsigned_integer (buf, 4, byte_order, struct_addr);
write_memory (sp, buf, 4);
}
args_space += 4;
}
for (i = 0; i < nargs; i++)
{
struct type *arg_type = value_enclosing_type (args[i]);
if (i386_m128_p (arg_type) && num_m128 < 4)
{
if (write_pass)
{
const gdb_byte *val = value_contents_all (args[i]);
regcache->raw_write (I387_MM0_REGNUM(tdep) + num_m128, val);
}
num_m128++;
}
else
{
args_space = align_up (args_space,
i386_darwin_arg_type_alignment (arg_type));
if (write_pass)
write_memory (sp + args_space,
value_contents_all (args[i]),
TYPE_LENGTH (arg_type));
/* The System V ABI says that:
"An argument's size is increased, if necessary, to make it a
multiple of [32-bit] words. This may require tail padding,
depending on the size of the argument."
This makes sure the stack stays word-aligned. */
args_space += align_up (TYPE_LENGTH (arg_type), 4);
}
}
/* Darwin i386 ABI:
1. The caller ensures that the stack is 16-byte aligned at the point
of the function call. */
if (!write_pass)
sp = align_down (sp - args_space, 16);
}
/* Store return address. */
sp -= 4;
store_unsigned_integer (buf, 4, byte_order, bp_addr);
write_memory (sp, buf, 4);
/* Finally, update the stack pointer... */
store_unsigned_integer (buf, 4, byte_order, sp);
regcache->cooked_write (I386_ESP_REGNUM, buf);
/* ...and fake a frame pointer. */
regcache->cooked_write (I386_EBP_REGNUM, buf);
/* MarkK wrote: This "+ 8" is all over the place:
(i386_frame_this_id, i386_sigtramp_frame_this_id,
i386_dummy_id). It's there, since all frame unwinders for
a given target have to agree (within a certain margin) on the
definition of the stack address of a frame. Otherwise frame id
comparison might not work correctly. Since DWARF2/GCC uses the
stack address *before* the function call as a frame's CFA. On
the i386, when %ebp is used as a frame pointer, the offset
between the contents %ebp and the CFA as defined by GCC. */
return sp + 8;
}
static void
i386_darwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
/* We support the SSE registers. */
tdep->num_xmm_regs = I386_NUM_XREGS - 1;
set_gdbarch_num_regs (gdbarch, I386_SSE_NUM_REGS);
dwarf2_frame_set_signal_frame_p (gdbarch, darwin_dwarf_signal_frame_p);
set_gdbarch_push_dummy_call (gdbarch, i386_darwin_push_dummy_call);
tdep->struct_return = reg_struct_return;
tdep->sigtramp_p = i386_sigtramp_p;
tdep->sigcontext_addr = i386_darwin_sigcontext_addr;
tdep->sc_reg_offset = i386_darwin_thread_state_reg_offset;
tdep->sc_num_regs = i386_darwin_thread_state_num_regs;
tdep->jb_pc_offset = 48;
/* Although the i387 extended floating-point has only 80 significant
bits, a `long double' actually takes up 128, probably to enforce
alignment. */
set_gdbarch_long_double_bit (gdbarch, 128);
set_solib_ops (gdbarch, &darwin_so_ops);
}
static enum gdb_osabi
i386_mach_o_osabi_sniffer (bfd *abfd)
{
if (!bfd_check_format (abfd, bfd_object))
return GDB_OSABI_UNKNOWN;
if (bfd_get_arch (abfd) == bfd_arch_i386)
return GDB_OSABI_DARWIN;
return GDB_OSABI_UNKNOWN;
}
void
_initialize_i386_darwin_tdep (void)
{
gdbarch_register_osabi_sniffer (bfd_arch_unknown, bfd_target_mach_o_flavour,
i386_mach_o_osabi_sniffer);
gdbarch_register_osabi (bfd_arch_i386, bfd_mach_i386_i386,
GDB_OSABI_DARWIN, i386_darwin_init_abi);
}