1 /* Darwin support for GDB, the GNU debugger. 2 Copyright (C) 1997-2017 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 "objfiles.h" 30 31 #include "i387-tdep.h" 32 #include "i386-tdep.h" 33 #include "osabi.h" 34 #include "ui-out.h" 35 #include "i386-darwin-tdep.h" 36 #include "solib.h" 37 #include "solib-darwin.h" 38 #include "dwarf2-frame.h" 39 #include <algorithm> 40 41 /* Offsets into the struct i386_thread_state where we'll find the saved regs. 42 From <mach/i386/thread_status.h> and i386-tdep.h. */ 43 int i386_darwin_thread_state_reg_offset[] = 44 { 45 0 * 4, /* EAX */ 46 2 * 4, /* ECX */ 47 3 * 4, /* EDX */ 48 1 * 4, /* EBX */ 49 7 * 4, /* ESP */ 50 6 * 4, /* EBP */ 51 5 * 4, /* ESI */ 52 4 * 4, /* EDI */ 53 10 * 4, /* EIP */ 54 9 * 4, /* EFLAGS */ 55 11 * 4, /* CS */ 56 8 * 4, /* SS */ 57 12 * 4, /* DS */ 58 13 * 4, /* ES */ 59 14 * 4, /* FS */ 60 15 * 4 /* GS */ 61 }; 62 63 const int i386_darwin_thread_state_num_regs = 64 ARRAY_SIZE (i386_darwin_thread_state_reg_offset); 65 66 /* Assuming THIS_FRAME is a Darwin sigtramp routine, return the 67 address of the associated sigcontext structure. */ 68 69 static CORE_ADDR 70 i386_darwin_sigcontext_addr (struct frame_info *this_frame) 71 { 72 struct gdbarch *gdbarch = get_frame_arch (this_frame); 73 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 74 CORE_ADDR bp; 75 CORE_ADDR si; 76 gdb_byte buf[4]; 77 78 get_frame_register (this_frame, I386_EBP_REGNUM, buf); 79 bp = extract_unsigned_integer (buf, 4, byte_order); 80 81 /* A pointer to the ucontext is passed as the fourth argument 82 to the signal handler. */ 83 read_memory (bp + 24, buf, 4); 84 si = extract_unsigned_integer (buf, 4, byte_order); 85 86 /* The pointer to mcontext is at offset 28. */ 87 read_memory (si + 28, buf, 4); 88 89 /* First register (eax) is at offset 12. */ 90 return extract_unsigned_integer (buf, 4, byte_order) + 12; 91 } 92 93 /* Return true if the PC of THIS_FRAME is in a signal trampoline which 94 may have DWARF-2 CFI. 95 96 On Darwin, signal trampolines have DWARF-2 CFI but it has only one FDE 97 that covers only the indirect call to the user handler. 98 Without this function, the frame is recognized as a normal frame which is 99 not expected. */ 100 101 int 102 darwin_dwarf_signal_frame_p (struct gdbarch *gdbarch, 103 struct frame_info *this_frame) 104 { 105 return i386_sigtramp_p (this_frame); 106 } 107 108 /* Check wether TYPE is a 128-bit vector (__m128, __m128d or __m128i). */ 109 110 static int 111 i386_m128_p (struct type *type) 112 { 113 return (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type) 114 && TYPE_LENGTH (type) == 16); 115 } 116 117 /* Return the alignment for TYPE when passed as an argument. */ 118 119 static int 120 i386_darwin_arg_type_alignment (struct type *type) 121 { 122 type = check_typedef (type); 123 /* According to Mac OS X ABI document (passing arguments): 124 6. The caller places 64-bit vectors (__m64) on the parameter area, 125 aligned to 8-byte boundaries. 126 7. [...] The caller aligns 128-bit vectors in the parameter area to 127 16-byte boundaries. */ 128 if (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type)) 129 return TYPE_LENGTH (type); 130 /* 4. The caller places all the fields of structures (or unions) with no 131 vector elements in the parameter area. These structures are 4-byte 132 aligned. 133 5. The caller places structures with vector elements on the stack, 134 16-byte aligned. */ 135 if (TYPE_CODE (type) == TYPE_CODE_STRUCT 136 || TYPE_CODE (type) == TYPE_CODE_UNION) 137 { 138 int i; 139 int res = 4; 140 for (i = 0; i < TYPE_NFIELDS (type); i++) 141 { 142 int align 143 = i386_darwin_arg_type_alignment (TYPE_FIELD_TYPE (type, i)); 144 145 res = std::max (res, align); 146 } 147 return res; 148 } 149 /* 2. The caller aligns nonvector arguments to 4-byte boundaries. */ 150 return 4; 151 } 152 153 static CORE_ADDR 154 i386_darwin_push_dummy_call (struct gdbarch *gdbarch, struct value *function, 155 struct regcache *regcache, CORE_ADDR bp_addr, 156 int nargs, struct value **args, CORE_ADDR sp, 157 int struct_return, CORE_ADDR struct_addr) 158 { 159 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 160 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 161 gdb_byte buf[4]; 162 int i; 163 int write_pass; 164 165 /* Determine the total space required for arguments and struct 166 return address in a first pass, then push arguments in a second pass. */ 167 168 for (write_pass = 0; write_pass < 2; write_pass++) 169 { 170 int args_space = 0; 171 int num_m128 = 0; 172 173 if (struct_return) 174 { 175 if (write_pass) 176 { 177 /* Push value address. */ 178 store_unsigned_integer (buf, 4, byte_order, struct_addr); 179 write_memory (sp, buf, 4); 180 } 181 args_space += 4; 182 } 183 184 for (i = 0; i < nargs; i++) 185 { 186 struct type *arg_type = value_enclosing_type (args[i]); 187 188 if (i386_m128_p (arg_type) && num_m128 < 4) 189 { 190 if (write_pass) 191 { 192 const gdb_byte *val = value_contents_all (args[i]); 193 regcache_raw_write 194 (regcache, I387_MM0_REGNUM(tdep) + num_m128, val); 195 } 196 num_m128++; 197 } 198 else 199 { 200 args_space = align_up (args_space, 201 i386_darwin_arg_type_alignment (arg_type)); 202 if (write_pass) 203 write_memory (sp + args_space, 204 value_contents_all (args[i]), 205 TYPE_LENGTH (arg_type)); 206 207 /* The System V ABI says that: 208 209 "An argument's size is increased, if necessary, to make it a 210 multiple of [32-bit] words. This may require tail padding, 211 depending on the size of the argument." 212 213 This makes sure the stack stays word-aligned. */ 214 args_space += align_up (TYPE_LENGTH (arg_type), 4); 215 } 216 } 217 218 /* Darwin i386 ABI: 219 1. The caller ensures that the stack is 16-byte aligned at the point 220 of the function call. */ 221 if (!write_pass) 222 sp = align_down (sp - args_space, 16); 223 } 224 225 /* Store return address. */ 226 sp -= 4; 227 store_unsigned_integer (buf, 4, byte_order, bp_addr); 228 write_memory (sp, buf, 4); 229 230 /* Finally, update the stack pointer... */ 231 store_unsigned_integer (buf, 4, byte_order, sp); 232 regcache_cooked_write (regcache, I386_ESP_REGNUM, buf); 233 234 /* ...and fake a frame pointer. */ 235 regcache_cooked_write (regcache, I386_EBP_REGNUM, buf); 236 237 /* MarkK wrote: This "+ 8" is all over the place: 238 (i386_frame_this_id, i386_sigtramp_frame_this_id, 239 i386_dummy_id). It's there, since all frame unwinders for 240 a given target have to agree (within a certain margin) on the 241 definition of the stack address of a frame. Otherwise frame id 242 comparison might not work correctly. Since DWARF2/GCC uses the 243 stack address *before* the function call as a frame's CFA. On 244 the i386, when %ebp is used as a frame pointer, the offset 245 between the contents %ebp and the CFA as defined by GCC. */ 246 return sp + 8; 247 } 248 249 static void 250 i386_darwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 251 { 252 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 253 254 /* We support the SSE registers. */ 255 tdep->num_xmm_regs = I386_NUM_XREGS - 1; 256 set_gdbarch_num_regs (gdbarch, I386_SSE_NUM_REGS); 257 258 dwarf2_frame_set_signal_frame_p (gdbarch, darwin_dwarf_signal_frame_p); 259 set_gdbarch_push_dummy_call (gdbarch, i386_darwin_push_dummy_call); 260 261 tdep->struct_return = reg_struct_return; 262 263 tdep->sigtramp_p = i386_sigtramp_p; 264 tdep->sigcontext_addr = i386_darwin_sigcontext_addr; 265 tdep->sc_reg_offset = i386_darwin_thread_state_reg_offset; 266 tdep->sc_num_regs = i386_darwin_thread_state_num_regs; 267 268 tdep->jb_pc_offset = 48; 269 270 /* Although the i387 extended floating-point has only 80 significant 271 bits, a `long double' actually takes up 128, probably to enforce 272 alignment. */ 273 set_gdbarch_long_double_bit (gdbarch, 128); 274 275 set_solib_ops (gdbarch, &darwin_so_ops); 276 } 277 278 static enum gdb_osabi 279 i386_mach_o_osabi_sniffer (bfd *abfd) 280 { 281 if (!bfd_check_format (abfd, bfd_object)) 282 return GDB_OSABI_UNKNOWN; 283 284 if (bfd_get_arch (abfd) == bfd_arch_i386) 285 return GDB_OSABI_DARWIN; 286 287 return GDB_OSABI_UNKNOWN; 288 } 289 290 /* -Wmissing-prototypes */ 291 extern initialize_file_ftype _initialize_i386_darwin_tdep; 292 293 void 294 _initialize_i386_darwin_tdep (void) 295 { 296 gdbarch_register_osabi_sniffer (bfd_arch_unknown, bfd_target_mach_o_flavour, 297 i386_mach_o_osabi_sniffer); 298 299 gdbarch_register_osabi (bfd_arch_i386, bfd_mach_i386_i386, 300 GDB_OSABI_DARWIN, i386_darwin_init_abi); 301 } 302