1 /* Darwin support for GDB, the GNU debugger. 2 Copyright (C) 1997-2020 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 "symtab.h" 27 #include "regcache.h" 28 #include "objfiles.h" 29 30 #include "i387-tdep.h" 31 #include "i386-tdep.h" 32 #include "osabi.h" 33 #include "ui-out.h" 34 #include "i386-darwin-tdep.h" 35 #include "solib.h" 36 #include "solib-darwin.h" 37 #include "dwarf2/frame.h" 38 #include <algorithm> 39 40 /* Offsets into the struct i386_thread_state where we'll find the saved regs. 41 From <mach/i386/thread_status.h> and i386-tdep.h. */ 42 int i386_darwin_thread_state_reg_offset[] = 43 { 44 0 * 4, /* EAX */ 45 2 * 4, /* ECX */ 46 3 * 4, /* EDX */ 47 1 * 4, /* EBX */ 48 7 * 4, /* ESP */ 49 6 * 4, /* EBP */ 50 5 * 4, /* ESI */ 51 4 * 4, /* EDI */ 52 10 * 4, /* EIP */ 53 9 * 4, /* EFLAGS */ 54 11 * 4, /* CS */ 55 8 * 4, /* SS */ 56 12 * 4, /* DS */ 57 13 * 4, /* ES */ 58 14 * 4, /* FS */ 59 15 * 4 /* GS */ 60 }; 61 62 const int i386_darwin_thread_state_num_regs = 63 ARRAY_SIZE (i386_darwin_thread_state_reg_offset); 64 65 /* Assuming THIS_FRAME is a Darwin sigtramp routine, return the 66 address of the associated sigcontext structure. */ 67 68 static CORE_ADDR 69 i386_darwin_sigcontext_addr (struct frame_info *this_frame) 70 { 71 struct gdbarch *gdbarch = get_frame_arch (this_frame); 72 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 73 CORE_ADDR bp; 74 CORE_ADDR si; 75 gdb_byte buf[4]; 76 77 get_frame_register (this_frame, I386_EBP_REGNUM, buf); 78 bp = extract_unsigned_integer (buf, 4, byte_order); 79 80 /* A pointer to the ucontext is passed as the fourth argument 81 to the signal handler. */ 82 read_memory (bp + 24, buf, 4); 83 si = extract_unsigned_integer (buf, 4, byte_order); 84 85 /* The pointer to mcontext is at offset 28. */ 86 read_memory (si + 28, buf, 4); 87 88 /* First register (eax) is at offset 12. */ 89 return extract_unsigned_integer (buf, 4, byte_order) + 12; 90 } 91 92 /* Return true if the PC of THIS_FRAME is in a signal trampoline which 93 may have DWARF-2 CFI. 94 95 On Darwin, signal trampolines have DWARF-2 CFI but it has only one FDE 96 that covers only the indirect call to the user handler. 97 Without this function, the frame is recognized as a normal frame which is 98 not expected. */ 99 100 int 101 darwin_dwarf_signal_frame_p (struct gdbarch *gdbarch, 102 struct frame_info *this_frame) 103 { 104 return i386_sigtramp_p (this_frame); 105 } 106 107 /* Check whether TYPE is a 128-bit vector (__m128, __m128d or __m128i). */ 108 109 static int 110 i386_m128_p (struct type *type) 111 { 112 return (type->code () == TYPE_CODE_ARRAY && TYPE_VECTOR (type) 113 && TYPE_LENGTH (type) == 16); 114 } 115 116 /* Return the alignment for TYPE when passed as an argument. */ 117 118 static int 119 i386_darwin_arg_type_alignment (struct type *type) 120 { 121 type = check_typedef (type); 122 /* According to Mac OS X ABI document (passing arguments): 123 6. The caller places 64-bit vectors (__m64) on the parameter area, 124 aligned to 8-byte boundaries. 125 7. [...] The caller aligns 128-bit vectors in the parameter area to 126 16-byte boundaries. */ 127 if (type->code () == TYPE_CODE_ARRAY && TYPE_VECTOR (type)) 128 return TYPE_LENGTH (type); 129 /* 4. The caller places all the fields of structures (or unions) with no 130 vector elements in the parameter area. These structures are 4-byte 131 aligned. 132 5. The caller places structures with vector elements on the stack, 133 16-byte aligned. */ 134 if (type->code () == TYPE_CODE_STRUCT 135 || type->code () == TYPE_CODE_UNION) 136 { 137 int i; 138 int res = 4; 139 for (i = 0; i < type->num_fields (); i++) 140 { 141 int align 142 = i386_darwin_arg_type_alignment (type->field (i).type ()); 143 144 res = std::max (res, align); 145 } 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 function_call_return_method return_method, 157 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 (return_method == return_method_struct) 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 (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 (I386_ESP_REGNUM, buf); 232 233 /* ...and fake a frame pointer. */ 234 regcache->cooked_write (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 void _initialize_i386_darwin_tdep (); 290 void 291 _initialize_i386_darwin_tdep () 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