gdb/amd64-windows-tdep.c

   1 /* Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc.
   2
   3    This file is part of GDB.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include "defs.h"
  19 #include "osabi.h"
  20 #include "amd64-tdep.h"
  21 #include "solib.h"
  22 #include "solib-target.h"
  23 #include "gdbtypes.h"
  24 #include "gdbcore.h"
  25 #include "regcache.h"
  26
  27 /* The registers used to pass integer arguments during a function call.  */
  28 static int amd64_windows_dummy_call_integer_regs[] =
  29 {
  30   AMD64_RCX_REGNUM,          /* %rcx */
  31   AMD64_RDX_REGNUM,          /* %rdx */
  32   8,                         /* %r8 */
  33   9                          /* %r9 */
  34 };
  35
  36 /* Implement the "classify" method in the gdbarch_tdep structure
  37    for amd64-windows.  */
  38
  39 static void
  40 amd64_windows_classify (struct type *type, enum amd64_reg_class class[2])
  41 {
  42   switch (TYPE_CODE (type))
  43     {
  44       case TYPE_CODE_ARRAY:
  45         /* Arrays are always passed by memory.  */
  46         class[0] = class[1] = AMD64_MEMORY;
  47         break;
  48
  49       case TYPE_CODE_STRUCT:
  50       case TYPE_CODE_UNION:
  51         /* Struct/Union types whose size is 1, 2, 4, or 8 bytes
  52            are passed as if they were integers of the same size.
  53            Types of different sizes are passed by memory.  */
  54         if (TYPE_LENGTH (type) == 1
  55             || TYPE_LENGTH (type) == 2
  56             || TYPE_LENGTH (type) == 4
  57             || TYPE_LENGTH (type) == 8)
  58           {
  59             class[0] = AMD64_INTEGER;
  60             class[1] = AMD64_NO_CLASS;
  61           }
  62         else
  63           class[0] = class[1] = AMD64_MEMORY;
  64         break;
  65
  66       default:
  67         /* For all the other types, the conventions are the same as
  68            with the System V ABI.  */
  69         amd64_classify (type, class);
  70     }
  71 }
  72
  73 /* Implement the "return_value" gdbarch method for amd64-windows.  */
  74
  75 static enum return_value_convention
  76 amd64_windows_return_value (struct gdbarch *gdbarch, struct type *func_type,
  77                             struct type *type, struct regcache *regcache,
  78                             gdb_byte *readbuf, const gdb_byte *writebuf)
  79 {
  80   int len = TYPE_LENGTH (type);
  81   int regnum = -1;
  82
  83   /* See if our value is returned through a register.  If it is, then
  84      store the associated register number in REGNUM.  */
  85   switch (TYPE_CODE (type))
  86     {
  87       case TYPE_CODE_FLT:
  88       case TYPE_CODE_DECFLOAT:
  89         /* __m128, __m128i, __m128d, floats, and doubles are returned
  90            via XMM0.  */
  91         if (len == 4 || len == 8 || len == 16)
  92           regnum = AMD64_XMM0_REGNUM;
  93         break;
  94       default:
  95         /* All other values that are 1, 2, 4 or 8 bytes long are returned
  96            via RAX.  */
  97         if (len == 1 || len == 2 || len == 4 || len == 8)
  98           regnum = AMD64_RAX_REGNUM;
  99         break;
 100     }
 101
 102   if (regnum < 0)
 103     {
 104       /* RAX contains the address where the return value has been stored.  */
 105       if (readbuf)
 106         {
 107           ULONGEST addr;
 108
 109           regcache_raw_read_unsigned (regcache, AMD64_RAX_REGNUM, &addr);
 110           read_memory (addr, readbuf, TYPE_LENGTH (type));
 111         }
 112       return RETURN_VALUE_ABI_RETURNS_ADDRESS;
 113     }
 114   else
 115     {
 116       /* Extract the return value from the register where it was stored.  */
 117       if (readbuf)
 118         regcache_raw_read_part (regcache, regnum, 0, len, readbuf);
 119       if (writebuf)
 120         regcache_raw_write_part (regcache, regnum, 0, len, writebuf);
 121       return RETURN_VALUE_REGISTER_CONVENTION;
 122     }
 123 }
 124
 125 /* Check that the code pointed to by PC corresponds to a call to
 126    __main, skip it if so.  Return PC otherwise.  */
 127
 128 static CORE_ADDR
 129 amd64_skip_main_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 130 {
 131   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 132   gdb_byte op;
 133
 134   target_read_memory (pc, &op, 1);
 135   if (op == 0xe8)
 136     {
 137       gdb_byte buf[4];
 138
 139       if (target_read_memory (pc + 1, buf, sizeof buf) == 0)
 140         {
 141           struct minimal_symbol *s;
 142           CORE_ADDR call_dest;
 143
 144           call_dest = pc + 5 + extract_signed_integer (buf, 4, byte_order);
 145           s = lookup_minimal_symbol_by_pc (call_dest);
 146           if (s != NULL
 147               && SYMBOL_LINKAGE_NAME (s) != NULL
 148               && strcmp (SYMBOL_LINKAGE_NAME (s), "__main") == 0)
 149             pc += 5;
 150         }
 151     }
 152
 153   return pc;
 154 }
 155
 156
 157 static void
 158 amd64_windows_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 159 {
 160   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 161
 162   amd64_init_abi (info, gdbarch);
 163
 164   /* On Windows, "long"s are only 32bit.  */
 165   set_gdbarch_long_bit (gdbarch, 32);
 166
 167   /* Function calls.  */
 168   tdep->call_dummy_num_integer_regs =
 169     ARRAY_SIZE (amd64_windows_dummy_call_integer_regs);
 170   tdep->call_dummy_integer_regs = amd64_windows_dummy_call_integer_regs;
 171   tdep->classify = amd64_windows_classify;
 172   tdep->memory_args_by_pointer = 1;
 173   tdep->integer_param_regs_saved_in_caller_frame = 1;
 174   set_gdbarch_return_value (gdbarch, amd64_windows_return_value);
 175   set_gdbarch_skip_main_prologue (gdbarch, amd64_skip_main_prologue);
 176
 177   set_solib_ops (gdbarch, &solib_target_so_ops);
 178 }
 179
 180 void
 181 _initialize_amd64_windows_tdep (void)
 182 {
 183   gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, GDB_OSABI_CYGWIN,
 184                           amd64_windows_init_abi);
 185 }
 186