1 /* Darwin support for GDB, the GNU debugger. 2 Copyright (C) 1997-2013 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 "symtab.h" 37 #include "frame.h" 38 #include "gdb_assert.h" 39 #include "i386-darwin-tdep.h" 40 #include "solib.h" 41 #include "solib-darwin.h" 42 #include "dwarf2-frame.h" 43 44 /* Offsets into the struct i386_thread_state where we'll find the saved regs. 45 From <mach/i386/thread_status.h> and i386-tdep.h. */ 46 int i386_darwin_thread_state_reg_offset[] = 47 { 48 0 * 4, /* EAX */ 49 2 * 4, /* ECX */ 50 3 * 4, /* EDX */ 51 1 * 4, /* EBX */ 52 7 * 4, /* ESP */ 53 6 * 4, /* EBP */ 54 5 * 4, /* ESI */ 55 4 * 4, /* EDI */ 56 10 * 4, /* EIP */ 57 9 * 4, /* EFLAGS */ 58 11 * 4, /* CS */ 59 8 * 4, /* SS */ 60 12 * 4, /* DS */ 61 13 * 4, /* ES */ 62 14 * 4, /* FS */ 63 15 * 4 /* GS */ 64 }; 65 66 const int i386_darwin_thread_state_num_regs = 67 ARRAY_SIZE (i386_darwin_thread_state_reg_offset); 68 69 /* Assuming THIS_FRAME is a Darwin sigtramp routine, return the 70 address of the associated sigcontext structure. */ 71 72 static CORE_ADDR 73 i386_darwin_sigcontext_addr (struct frame_info *this_frame) 74 { 75 struct gdbarch *gdbarch = get_frame_arch (this_frame); 76 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 77 CORE_ADDR bp; 78 CORE_ADDR si; 79 gdb_byte buf[4]; 80 81 get_frame_register (this_frame, I386_EBP_REGNUM, buf); 82 bp = extract_unsigned_integer (buf, 4, byte_order); 83 84 /* A pointer to the ucontext is passed as the fourth argument 85 to the signal handler. */ 86 read_memory (bp + 24, buf, 4); 87 si = extract_unsigned_integer (buf, 4, byte_order); 88 89 /* The pointer to mcontext is at offset 28. */ 90 read_memory (si + 28, buf, 4); 91 92 /* First register (eax) is at offset 12. */ 93 return extract_unsigned_integer (buf, 4, byte_order) + 12; 94 } 95 96 /* Return true if the PC of THIS_FRAME is in a signal trampoline which 97 may have DWARF-2 CFI. 98 99 On Darwin, signal trampolines have DWARF-2 CFI but it has only one FDE 100 that covers only the indirect call to the user handler. 101 Without this function, the frame is recognized as a normal frame which is 102 not expected. */ 103 104 int 105 darwin_dwarf_signal_frame_p (struct gdbarch *gdbarch, 106 struct frame_info *this_frame) 107 { 108 return i386_sigtramp_p (this_frame); 109 } 110 111 /* Check wether TYPE is a 128-bit vector (__m128, __m128d or __m128i). */ 112 113 static int 114 i386_m128_p (struct type *type) 115 { 116 return (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type) 117 && TYPE_LENGTH (type) == 16); 118 } 119 120 /* Return the alignment for TYPE when passed as an argument. */ 121 122 static int 123 i386_darwin_arg_type_alignment (struct type *type) 124 { 125 type = check_typedef (type); 126 /* According to Mac OS X ABI document (passing arguments): 127 6. The caller places 64-bit vectors (__m64) on the parameter area, 128 aligned to 8-byte boundaries. 129 7. [...] The caller aligns 128-bit vectors in the parameter area to 130 16-byte boundaries. */ 131 if (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type)) 132 return TYPE_LENGTH (type); 133 /* 4. The caller places all the fields of structures (or unions) with no 134 vector elements in the parameter area. These structures are 4-byte 135 aligned. 136 5. The caller places structures with vector elements on the stack, 137 16-byte aligned. */ 138 if (TYPE_CODE (type) == TYPE_CODE_STRUCT 139 || TYPE_CODE (type) == TYPE_CODE_UNION) 140 { 141 int i; 142 int res = 4; 143 for (i = 0; i < TYPE_NFIELDS (type); i++) 144 res = max (res, 145 i386_darwin_arg_type_alignment (TYPE_FIELD_TYPE (type, i))); 146 return res; 147 } 148 /* 2. The caller aligns nonvector arguments to 4-byte boundaries. */ 149 return 4; 150 } 151 152 static CORE_ADDR 153 i386_darwin_push_dummy_call (struct gdbarch *gdbarch, struct value *function, 154 struct regcache *regcache, CORE_ADDR bp_addr, 155 int nargs, struct value **args, CORE_ADDR sp, 156 int struct_return, CORE_ADDR struct_addr) 157 { 158 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 159 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 160 gdb_byte buf[4]; 161 int i; 162 int write_pass; 163 164 /* Determine the total space required for arguments and struct 165 return address in a first pass, then push arguments in a second pass. */ 166 167 for (write_pass = 0; write_pass < 2; write_pass++) 168 { 169 int args_space = 0; 170 int num_m128 = 0; 171 172 if (struct_return) 173 { 174 if (write_pass) 175 { 176 /* Push value address. */ 177 store_unsigned_integer (buf, 4, byte_order, struct_addr); 178 write_memory (sp, buf, 4); 179 } 180 args_space += 4; 181 } 182 183 for (i = 0; i < nargs; i++) 184 { 185 struct type *arg_type = value_enclosing_type (args[i]); 186 187 if (i386_m128_p (arg_type) && num_m128 < 4) 188 { 189 if (write_pass) 190 { 191 const gdb_byte *val = value_contents_all (args[i]); 192 regcache_raw_write 193 (regcache, I387_MM0_REGNUM(tdep) + num_m128, val); 194 } 195 num_m128++; 196 } 197 else 198 { 199 args_space = align_up (args_space, 200 i386_darwin_arg_type_alignment (arg_type)); 201 if (write_pass) 202 write_memory (sp + args_space, 203 value_contents_all (args[i]), 204 TYPE_LENGTH (arg_type)); 205 206 /* The System V ABI says that: 207 208 "An argument's size is increased, if necessary, to make it a 209 multiple of [32-bit] words. This may require tail padding, 210 depending on the size of the argument." 211 212 This makes sure the stack stays word-aligned. */ 213 args_space += align_up (TYPE_LENGTH (arg_type), 4); 214 } 215 } 216 217 /* Darwin i386 ABI: 218 1. The caller ensures that the stack is 16-byte aligned at the point 219 of the function call. */ 220 if (!write_pass) 221 sp = align_down (sp - args_space, 16); 222 } 223 224 /* Store return address. */ 225 sp -= 4; 226 store_unsigned_integer (buf, 4, byte_order, bp_addr); 227 write_memory (sp, buf, 4); 228 229 /* Finally, update the stack pointer... */ 230 store_unsigned_integer (buf, 4, byte_order, sp); 231 regcache_cooked_write (regcache, I386_ESP_REGNUM, buf); 232 233 /* ...and fake a frame pointer. */ 234 regcache_cooked_write (regcache, I386_EBP_REGNUM, buf); 235 236 /* MarkK wrote: This "+ 8" is all over the place: 237 (i386_frame_this_id, i386_sigtramp_frame_this_id, 238 i386_dummy_id). It's there, since all frame unwinders for 239 a given target have to agree (within a certain margin) on the 240 definition of the stack address of a frame. Otherwise frame id 241 comparison might not work correctly. Since DWARF2/GCC uses the 242 stack address *before* the function call as a frame's CFA. On 243 the i386, when %ebp is used as a frame pointer, the offset 244 between the contents %ebp and the CFA as defined by GCC. */ 245 return sp + 8; 246 } 247 248 static void 249 i386_darwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 250 { 251 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 252 253 /* We support the SSE registers. */ 254 tdep->num_xmm_regs = I386_NUM_XREGS - 1; 255 set_gdbarch_num_regs (gdbarch, I386_SSE_NUM_REGS); 256 257 dwarf2_frame_set_signal_frame_p (gdbarch, darwin_dwarf_signal_frame_p); 258 set_gdbarch_push_dummy_call (gdbarch, i386_darwin_push_dummy_call); 259 260 tdep->struct_return = reg_struct_return; 261 262 tdep->sigtramp_p = i386_sigtramp_p; 263 tdep->sigcontext_addr = i386_darwin_sigcontext_addr; 264 tdep->sc_reg_offset = i386_darwin_thread_state_reg_offset; 265 tdep->sc_num_regs = i386_darwin_thread_state_num_regs; 266 267 tdep->jb_pc_offset = 48; 268 269 /* Although the i387 extended floating-point has only 80 significant 270 bits, a `long double' actually takes up 128, probably to enforce 271 alignment. */ 272 set_gdbarch_long_double_bit (gdbarch, 128); 273 274 set_solib_ops (gdbarch, &darwin_so_ops); 275 } 276 277 static enum gdb_osabi 278 i386_mach_o_osabi_sniffer (bfd *abfd) 279 { 280 if (!bfd_check_format (abfd, bfd_object)) 281 return GDB_OSABI_UNKNOWN; 282 283 if (bfd_get_arch (abfd) == bfd_arch_i386) 284 return GDB_OSABI_DARWIN; 285 286 return GDB_OSABI_UNKNOWN; 287 } 288 289 /* -Wmissing-prototypes */ 290 extern initialize_file_ftype _initialize_i386_darwin_tdep; 291 292 void 293 _initialize_i386_darwin_tdep (void) 294 { 295 gdbarch_register_osabi_sniffer (bfd_arch_unknown, bfd_target_mach_o_flavour, 296 i386_mach_o_osabi_sniffer); 297 298 gdbarch_register_osabi (bfd_arch_i386, bfd_mach_i386_i386, 299 GDB_OSABI_DARWIN, i386_darwin_init_abi); 300 } 301