/* Target-dependent code for Windows (including Cygwin) running on i386's,
   for GDB.

   Copyright (C) 2003-2021 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 "i386-tdep.h"
#include "windows-tdep.h"
#include "regset.h"
#include "gdb_obstack.h"
#include "xml-support.h"
#include "gdbcore.h"
#include "inferior.h"
#include "frame-unwind.h"

/* Core file support.  */

/* This vector maps GDB's idea of a register's number into an address
   in the windows exception context vector.  */

static int i386_windows_gregset_reg_offset[] =
{
  176, /* eax */
  172, /* ecx */
  168, /* edx */
  164, /* ebx */

  196, /* esp */
  180, /* ebp */
  160, /* esi */
  156, /* edi */

  184, /* eip */
  192, /* eflags */
  188, /* cs */
  200, /* ss */

  152, /* ds */
  148, /* es */
  144, /* fs */
  140, /* gs */

  56, /* FloatSave.RegisterArea[0 * 10] */
  66, /* FloatSave.RegisterArea[1 * 10] */
  76, /* FloatSave.RegisterArea[2 * 10] */
  86, /* FloatSave.RegisterArea[3 * 10] */
  96, /* FloatSave.RegisterArea[4 * 10] */
  106, /* FloatSave.RegisterArea[5 * 10] */
  116, /* FloatSave.RegisterArea[6 * 10] */
  126, /* FloatSave.RegisterArea[7 * 10] */

  28, /* FloatSave.ControlWord */
  32, /* FloatSave.StatusWord */
  36, /* FloatSave.TagWord */
  44, /* FloatSave.ErrorSelector */
  40, /* FloatSave.ErrorOffset */
  52, /* FloatSave.DataSelector */
  48, /* FloatSave.DataOffset */
  44, /* FloatSave.ErrorSelector */

  /* XMM0-7 */
  364, /* ExtendedRegisters[10*16] */
  380, /* ExtendedRegisters[11*16] */
  396, /* ExtendedRegisters[12*16] */
  412, /* ExtendedRegisters[13*16] */
  428, /* ExtendedRegisters[14*16] */
  444, /* ExtendedRegisters[15*16] */
  460, /* ExtendedRegisters[16*16] */
  476, /* ExtendedRegisters[17*16] */

  /* MXCSR */
  228 /* ExtendedRegisters[24] */
};

#define I386_WINDOWS_SIZEOF_GREGSET 716

static CORE_ADDR
i386_windows_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
{
  return i386_pe_skip_trampoline_code (frame, pc, NULL);
}

static const char *
i386_windows_auto_wide_charset (void)
{
  return "UTF-16";
}

static const struct insn_pattern i386_sigbe_bytes[] = {
  /* movl       $-4,%eax */
  { 0xb8, 0xff },
  { 0xfc, 0xff },
  { 0xff, 0xff },
  { 0xff, 0xff },
  { 0xff, 0xff },
  /* xadd       %eax,$tls::stackptr(%ebx) */
  { 0x0f, 0xff },
  { 0xc1, 0xff },
  { 0x83, 0xff },
  { 0x00, 0x00 }, /* 4 bytes for tls::stackptr */
  { 0x00, 0x00 },
  { 0x00, 0x00 },
  { 0x00, 0x00 }
};

#define COUNT(x) (sizeof(x)/sizeof(x[0]))

static const struct insn_pattern_sequence i386_sigbe =
  {
    i386_sigbe_bytes, COUNT(i386_sigbe_bytes)
  };

/* Implement the "push_dummy_call" gdbarch method.  */

static CORE_ADDR
i386_windows_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)
{
  /* For non-static member functions of 32bit Windows programs, the thiscall
     calling convention is used, so the 'this' pointer is passed in ECX.  */
  bool thiscall = false;

  struct type *type = check_typedef (value_type (function));
  if (type->code () == TYPE_CODE_PTR)
    type = check_typedef (TYPE_TARGET_TYPE (type));

  /* read_subroutine_type sets for non-static member functions the
     artificial flag of the first parameter ('this' pointer).  */
  if (type->code () == TYPE_CODE_METHOD
      && type->num_fields () > 0
      && TYPE_FIELD_ARTIFICIAL (type, 0)
      && type->field (0).type ()->code () == TYPE_CODE_PTR)
    thiscall = 1;

  return i386_thiscall_push_dummy_call (gdbarch, function, regcache, bp_addr,
					nargs, args, sp, return_method,
					struct_addr, thiscall);
}

/* Common parts for gdbarch initialization for Windows and Cygwin on i386.  */

static void
i386_windows_init_abi_common (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  set_gdbarch_skip_trampoline_code (gdbarch, i386_windows_skip_trampoline_code);

  set_gdbarch_skip_main_prologue (gdbarch, i386_skip_main_prologue);

  tdep->struct_return = reg_struct_return;

  tdep->gregset_reg_offset = i386_windows_gregset_reg_offset;
  tdep->gregset_num_regs = ARRAY_SIZE (i386_windows_gregset_reg_offset);
  tdep->sizeof_gregset = I386_WINDOWS_SIZEOF_GREGSET;

  tdep->sizeof_fpregset = 0;

  /* Core file support.  */
  set_gdbarch_core_xfer_shared_libraries
    (gdbarch, windows_core_xfer_shared_libraries);
  set_gdbarch_core_pid_to_str (gdbarch, windows_core_pid_to_str);

  set_gdbarch_auto_wide_charset (gdbarch, i386_windows_auto_wide_charset);
}

/* gdbarch initialization for Windows on i386.  */

static void
i386_windows_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  i386_windows_init_abi_common (info, gdbarch);
  windows_init_abi (info, gdbarch);

  set_gdbarch_push_dummy_call (gdbarch, i386_windows_push_dummy_call);
}

/* gdbarch initialization for Cygwin on i386.  */

static void
i386_cygwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  cygwin_sigwrapper_frame_unwind_set_sigbe_pattern (&i386_sigbe);
  frame_unwind_append_unwinder (gdbarch, &cygwin_sigwrapper_frame_unwind);

  i386_windows_init_abi_common (info, gdbarch);
  cygwin_init_abi (info, gdbarch);
}

static gdb_osabi
i386_windows_osabi_sniffer (bfd *abfd)
{
  const char *target_name = bfd_get_target (abfd);

  if (!streq (target_name, "pei-i386"))
    return GDB_OSABI_UNKNOWN;

  if (is_linked_with_cygwin_dll (abfd))
    return GDB_OSABI_CYGWIN;

  return GDB_OSABI_WINDOWS;
}

static enum gdb_osabi
i386_cygwin_core_osabi_sniffer (bfd *abfd)
{
  const char *target_name = bfd_get_target (abfd);

  /* Cygwin uses elf core dumps.  Do not claim all ELF executables,
     check whether there is a .reg section of proper size.  */
  if (strcmp (target_name, "elf32-i386") == 0)
    {
      asection *section = bfd_get_section_by_name (abfd, ".reg");
      if (section != nullptr
	  && bfd_section_size (section) == I386_WINDOWS_SIZEOF_GREGSET)
	return GDB_OSABI_CYGWIN;
    }

  return GDB_OSABI_UNKNOWN;
}

void _initialize_i386_windows_tdep ();
void
_initialize_i386_windows_tdep ()
{
  gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_coff_flavour,
                                  i386_windows_osabi_sniffer);

  /* Cygwin uses elf core dumps.  */
  gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_elf_flavour,
                                  i386_cygwin_core_osabi_sniffer);

  gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_WINDOWS,
                          i386_windows_init_abi);
  gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_CYGWIN,
			  i386_cygwin_init_abi);
}
