| 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 "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 wether 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) == 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) == 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) == TYPE_CODE_STRUCT |
| 135 | || TYPE_CODE (type) == TYPE_CODE_UNION) |
| 136 | { |
| 137 | int i; |
| 138 | int res = 4; |
| 139 | for (i = 0; i < TYPE_NFIELDS (type); i++) |
| 140 | { |
| 141 | int align |
| 142 | = i386_darwin_arg_type_alignment (TYPE_FIELD_TYPE (type, i)); |
| 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 | 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 | void |
| 290 | _initialize_i386_darwin_tdep (void) |
| 291 | { |
| 292 | gdbarch_register_osabi_sniffer (bfd_arch_unknown, bfd_target_mach_o_flavour, |
| 293 | i386_mach_o_osabi_sniffer); |
| 294 | |
| 295 | gdbarch_register_osabi (bfd_arch_i386, bfd_mach_i386_i386, |
| 296 | GDB_OSABI_DARWIN, i386_darwin_init_abi); |
| 297 | } |