1 /* Darwin support for GDB, the GNU debugger. 2 Copyright (C) 1997-2014 Free Software Foundation, Inc. 3 4 Contributed by Apple Computer, Inc. 5 6 This file is part of GDB. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 20 21 #include "defs.h" 22 #include "frame.h" 23 #include "inferior.h" 24 #include "gdbcore.h" 25 #include "target.h" 26 #include "floatformat.h" 27 #include "symtab.h" 28 #include "regcache.h" 29 #include "libbfd.h" 30 #include "objfiles.h" 31 32 #include "i387-tdep.h" 33 #include "i386-tdep.h" 34 #include "osabi.h" 35 #include "ui-out.h" 36 #include "gdb_assert.h" 37 #include "i386-darwin-tdep.h" 38 #include "solib.h" 39 #include "solib-darwin.h" 40 #include "dwarf2-frame.h" 41 42 /* Offsets into the struct i386_thread_state where we'll find the saved regs. 43 From <mach/i386/thread_status.h> and i386-tdep.h. */ 44 int i386_darwin_thread_state_reg_offset[] = 45 { 46 0 * 4, /* EAX */ 47 2 * 4, /* ECX */ 48 3 * 4, /* EDX */ 49 1 * 4, /* EBX */ 50 7 * 4, /* ESP */ 51 6 * 4, /* EBP */ 52 5 * 4, /* ESI */ 53 4 * 4, /* EDI */ 54 10 * 4, /* EIP */ 55 9 * 4, /* EFLAGS */ 56 11 * 4, /* CS */ 57 8 * 4, /* SS */ 58 12 * 4, /* DS */ 59 13 * 4, /* ES */ 60 14 * 4, /* FS */ 61 15 * 4 /* GS */ 62 }; 63 64 const int i386_darwin_thread_state_num_regs = 65 ARRAY_SIZE (i386_darwin_thread_state_reg_offset); 66 67 /* Assuming THIS_FRAME is a Darwin sigtramp routine, return the 68 address of the associated sigcontext structure. */ 69 70 static CORE_ADDR 71 i386_darwin_sigcontext_addr (struct frame_info *this_frame) 72 { 73 struct gdbarch *gdbarch = get_frame_arch (this_frame); 74 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 75 CORE_ADDR bp; 76 CORE_ADDR si; 77 gdb_byte buf[4]; 78 79 get_frame_register (this_frame, I386_EBP_REGNUM, buf); 80 bp = extract_unsigned_integer (buf, 4, byte_order); 81 82 /* A pointer to the ucontext is passed as the fourth argument 83 to the signal handler. */ 84 read_memory (bp + 24, buf, 4); 85 si = extract_unsigned_integer (buf, 4, byte_order); 86 87 /* The pointer to mcontext is at offset 28. */ 88 read_memory (si + 28, buf, 4); 89 90 /* First register (eax) is at offset 12. */ 91 return extract_unsigned_integer (buf, 4, byte_order) + 12; 92 } 93 94 /* Return true if the PC of THIS_FRAME is in a signal trampoline which 95 may have DWARF-2 CFI. 96 97 On Darwin, signal trampolines have DWARF-2 CFI but it has only one FDE 98 that covers only the indirect call to the user handler. 99 Without this function, the frame is recognized as a normal frame which is 100 not expected. */ 101 102 int 103 darwin_dwarf_signal_frame_p (struct gdbarch *gdbarch, 104 struct frame_info *this_frame) 105 { 106 return i386_sigtramp_p (this_frame); 107 } 108 109 /* Check wether TYPE is a 128-bit vector (__m128, __m128d or __m128i). */ 110 111 static int 112 i386_m128_p (struct type *type) 113 { 114 return (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type) 115 && TYPE_LENGTH (type) == 16); 116 } 117 118 /* Return the alignment for TYPE when passed as an argument. */ 119 120 static int 121 i386_darwin_arg_type_alignment (struct type *type) 122 { 123 type = check_typedef (type); 124 /* According to Mac OS X ABI document (passing arguments): 125 6. The caller places 64-bit vectors (__m64) on the parameter area, 126 aligned to 8-byte boundaries. 127 7. [...] The caller aligns 128-bit vectors in the parameter area to 128 16-byte boundaries. */ 129 if (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type)) 130 return TYPE_LENGTH (type); 131 /* 4. The caller places all the fields of structures (or unions) with no 132 vector elements in the parameter area. These structures are 4-byte 133 aligned. 134 5. The caller places structures with vector elements on the stack, 135 16-byte aligned. */ 136 if (TYPE_CODE (type) == TYPE_CODE_STRUCT 137 || TYPE_CODE (type) == TYPE_CODE_UNION) 138 { 139 int i; 140 int res = 4; 141 for (i = 0; i < TYPE_NFIELDS (type); i++) 142 res = max (res, 143 i386_darwin_arg_type_alignment (TYPE_FIELD_TYPE (type, i))); 144 return res; 145 } 146 /* 2. The caller aligns nonvector arguments to 4-byte boundaries. */ 147 return 4; 148 } 149 150 static CORE_ADDR 151 i386_darwin_push_dummy_call (struct gdbarch *gdbarch, struct value *function, 152 struct regcache *regcache, CORE_ADDR bp_addr, 153 int nargs, struct value **args, CORE_ADDR sp, 154 int struct_return, CORE_ADDR struct_addr) 155 { 156 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 157 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 158 gdb_byte buf[4]; 159 int i; 160 int write_pass; 161 162 /* Determine the total space required for arguments and struct 163 return address in a first pass, then push arguments in a second pass. */ 164 165 for (write_pass = 0; write_pass < 2; write_pass++) 166 { 167 int args_space = 0; 168 int num_m128 = 0; 169 170 if (struct_return) 171 { 172 if (write_pass) 173 { 174 /* Push value address. */ 175 store_unsigned_integer (buf, 4, byte_order, struct_addr); 176 write_memory (sp, buf, 4); 177 } 178 args_space += 4; 179 } 180 181 for (i = 0; i < nargs; i++) 182 { 183 struct type *arg_type = value_enclosing_type (args[i]); 184 185 if (i386_m128_p (arg_type) && num_m128 < 4) 186 { 187 if (write_pass) 188 { 189 const gdb_byte *val = value_contents_all (args[i]); 190 regcache_raw_write 191 (regcache, I387_MM0_REGNUM(tdep) + num_m128, val); 192 } 193 num_m128++; 194 } 195 else 196 { 197 args_space = align_up (args_space, 198 i386_darwin_arg_type_alignment (arg_type)); 199 if (write_pass) 200 write_memory (sp + args_space, 201 value_contents_all (args[i]), 202 TYPE_LENGTH (arg_type)); 203 204 /* The System V ABI says that: 205 206 "An argument's size is increased, if necessary, to make it a 207 multiple of [32-bit] words. This may require tail padding, 208 depending on the size of the argument." 209 210 This makes sure the stack stays word-aligned. */ 211 args_space += align_up (TYPE_LENGTH (arg_type), 4); 212 } 213 } 214 215 /* Darwin i386 ABI: 216 1. The caller ensures that the stack is 16-byte aligned at the point 217 of the function call. */ 218 if (!write_pass) 219 sp = align_down (sp - args_space, 16); 220 } 221 222 /* Store return address. */ 223 sp -= 4; 224 store_unsigned_integer (buf, 4, byte_order, bp_addr); 225 write_memory (sp, buf, 4); 226 227 /* Finally, update the stack pointer... */ 228 store_unsigned_integer (buf, 4, byte_order, sp); 229 regcache_cooked_write (regcache, I386_ESP_REGNUM, buf); 230 231 /* ...and fake a frame pointer. */ 232 regcache_cooked_write (regcache, I386_EBP_REGNUM, buf); 233 234 /* MarkK wrote: This "+ 8" is all over the place: 235 (i386_frame_this_id, i386_sigtramp_frame_this_id, 236 i386_dummy_id). It's there, since all frame unwinders for 237 a given target have to agree (within a certain margin) on the 238 definition of the stack address of a frame. Otherwise frame id 239 comparison might not work correctly. Since DWARF2/GCC uses the 240 stack address *before* the function call as a frame's CFA. On 241 the i386, when %ebp is used as a frame pointer, the offset 242 between the contents %ebp and the CFA as defined by GCC. */ 243 return sp + 8; 244 } 245 246 static void 247 i386_darwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 248 { 249 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 250 251 /* We support the SSE registers. */ 252 tdep->num_xmm_regs = I386_NUM_XREGS - 1; 253 set_gdbarch_num_regs (gdbarch, I386_SSE_NUM_REGS); 254 255 dwarf2_frame_set_signal_frame_p (gdbarch, darwin_dwarf_signal_frame_p); 256 set_gdbarch_push_dummy_call (gdbarch, i386_darwin_push_dummy_call); 257 258 tdep->struct_return = reg_struct_return; 259 260 tdep->sigtramp_p = i386_sigtramp_p; 261 tdep->sigcontext_addr = i386_darwin_sigcontext_addr; 262 tdep->sc_reg_offset = i386_darwin_thread_state_reg_offset; 263 tdep->sc_num_regs = i386_darwin_thread_state_num_regs; 264 265 tdep->jb_pc_offset = 48; 266 267 /* Although the i387 extended floating-point has only 80 significant 268 bits, a `long double' actually takes up 128, probably to enforce 269 alignment. */ 270 set_gdbarch_long_double_bit (gdbarch, 128); 271 272 set_solib_ops (gdbarch, &darwin_so_ops); 273 } 274 275 static enum gdb_osabi 276 i386_mach_o_osabi_sniffer (bfd *abfd) 277 { 278 if (!bfd_check_format (abfd, bfd_object)) 279 return GDB_OSABI_UNKNOWN; 280 281 if (bfd_get_arch (abfd) == bfd_arch_i386) 282 return GDB_OSABI_DARWIN; 283 284 return GDB_OSABI_UNKNOWN; 285 } 286 287 /* -Wmissing-prototypes */ 288 extern initialize_file_ftype _initialize_i386_darwin_tdep; 289 290 void 291 _initialize_i386_darwin_tdep (void) 292 { 293 gdbarch_register_osabi_sniffer (bfd_arch_unknown, bfd_target_mach_o_flavour, 294 i386_mach_o_osabi_sniffer); 295 296 gdbarch_register_osabi (bfd_arch_i386, bfd_mach_i386_i386, 297 GDB_OSABI_DARWIN, i386_darwin_init_abi); 298 } 299