1/* Darwin support for GDB, the GNU debugger. 2 Copyright 1997, 1998, 1999, 2000, 2001, 2002, 2005, 2008, 2009, 2010, 2011 3 Free Software Foundation, Inc. 4 5 Contributed by Apple Computer, Inc. 6 7 This file is part of GDB. 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 3 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 21 22#include "defs.h" 23#include "frame.h" 24#include "inferior.h" 25#include "gdbcore.h" 26#include "target.h" 27#include "floatformat.h" 28#include "symtab.h" 29#include "regcache.h" 30#include "libbfd.h" 31#include "objfiles.h" 32 33#include "i387-tdep.h" 34#include "i386-tdep.h" 35#include "osabi.h" 36#include "ui-out.h" 37#include "symtab.h" 38#include "frame.h" 39#include "gdb_assert.h" 40#include "i386-darwin-tdep.h" 41#include "solib.h" 42#include "solib-darwin.h" 43#include "dwarf2-frame.h" 44 45/* Offsets into the struct i386_thread_state where we'll find the saved regs. 46 From <mach/i386/thread_status.h> and i386-tdep.h. */ 47int i386_darwin_thread_state_reg_offset[] = 48{ 49 0 * 4, /* EAX */ 50 2 * 4, /* ECX */ 51 3 * 4, /* EDX */ 52 1 * 4, /* EBX */ 53 7 * 4, /* ESP */ 54 6 * 4, /* EBP */ 55 5 * 4, /* ESI */ 56 4 * 4, /* EDI */ 57 10 * 4, /* EIP */ 58 9 * 4, /* EFLAGS */ 59 11 * 4, /* CS */ 60 8, /* SS */ 61 12 * 4, /* DS */ 62 13 * 4, /* ES */ 63 14 * 4, /* FS */ 64 15 * 4 /* GS */ 65}; 66 67const int i386_darwin_thread_state_num_regs = 68 ARRAY_SIZE (i386_darwin_thread_state_reg_offset); 69 70/* Assuming THIS_FRAME is a Darwin sigtramp routine, return the 71 address of the associated sigcontext structure. */ 72 73static CORE_ADDR 74i386_darwin_sigcontext_addr (struct frame_info *this_frame) 75{ 76 struct gdbarch *gdbarch = get_frame_arch (this_frame); 77 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 78 CORE_ADDR bp; 79 CORE_ADDR si; 80 gdb_byte buf[4]; 81 82 get_frame_register (this_frame, I386_EBP_REGNUM, buf); 83 bp = extract_unsigned_integer (buf, 4, byte_order); 84 85 /* A pointer to the ucontext is passed as the fourth argument 86 to the signal handler. */ 87 read_memory (bp + 24, buf, 4); 88 si = extract_unsigned_integer (buf, 4, byte_order); 89 90 /* The pointer to mcontext is at offset 28. */ 91 read_memory (si + 28, buf, 4); 92 93 /* First register (eax) is at offset 12. */ 94 return extract_unsigned_integer (buf, 4, byte_order) + 12; 95} 96 97/* Return true if the PC of THIS_FRAME is in a signal trampoline which 98 may have DWARF-2 CFI. 99 100 On Darwin, signal trampolines have DWARF-2 CFI but it has only one FDE 101 that covers only the indirect call to the user handler. 102 Without this function, the frame is recognized as a normal frame which is 103 not expected. */ 104 105int 106darwin_dwarf_signal_frame_p (struct gdbarch *gdbarch, 107 struct frame_info *this_frame) 108{ 109 return i386_sigtramp_p (this_frame); 110} 111 112/* Check wether TYPE is a 128-bit vector (__m128, __m128d or __m128i). */ 113 114static int 115i386_m128_p (struct type *type) 116{ 117 return (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type) 118 && TYPE_LENGTH (type) == 16); 119} 120 121/* Return the alignment for TYPE when passed as an argument. */ 122 123static int 124i386_darwin_arg_type_alignment (struct type *type) 125{ 126 type = check_typedef (type); 127 /* According to Mac OS X ABI document (passing arguments): 128 6. The caller places 64-bit vectors (__m64) on the parameter area, 129 aligned to 8-byte boundaries. 130 7. [...] The caller aligns 128-bit vectors in the parameter area to 131 16-byte boundaries. */ 132 if (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type)) 133 return TYPE_LENGTH (type); 134 /* 4. The caller places all the fields of structures (or unions) with no 135 vector elements in the parameter area. These structures are 4-byte 136 aligned. 137 5. The caller places structures with vector elements on the stack, 138 16-byte aligned. */ 139 if (TYPE_CODE (type) == TYPE_CODE_STRUCT 140 || TYPE_CODE (type) == TYPE_CODE_UNION) 141 { 142 int i; 143 int res = 4; 144 for (i = 0; i < TYPE_NFIELDS (type); i++) 145 res = max (res, 146 i386_darwin_arg_type_alignment (TYPE_FIELD_TYPE (type, i))); 147 return res; 148 } 149 /* 2. The caller aligns nonvector arguments to 4-byte boundaries. */ 150 return 4; 151} 152 153static CORE_ADDR 154i386_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 int len = TYPE_LENGTH (arg_type); 201 int align = i386_darwin_arg_type_alignment (arg_type); 202 203 args_space = align_up (args_space, align); 204 if (write_pass) 205 write_memory (sp + args_space, 206 value_contents_all (args[i]), len); 207 208 /* The System V ABI says that: 209 210 "An argument's size is increased, if necessary, to make it a 211 multiple of [32-bit] words. This may require tail padding, 212 depending on the size of the argument." 213 214 This makes sure the stack stays word-aligned. */ 215 args_space += align_up (len, 4); 216 } 217 } 218 219 /* Darwin i386 ABI: 220 1. The caller ensures that the stack is 16-byte aligned at the point 221 of the function call. */ 222 if (!write_pass) 223 sp = align_down (sp - args_space, 16); 224 } 225 226 /* Store return address. */ 227 sp -= 4; 228 store_unsigned_integer (buf, 4, byte_order, bp_addr); 229 write_memory (sp, buf, 4); 230 231 /* Finally, update the stack pointer... */ 232 store_unsigned_integer (buf, 4, byte_order, sp); 233 regcache_cooked_write (regcache, I386_ESP_REGNUM, buf); 234 235 /* ...and fake a frame pointer. */ 236 regcache_cooked_write (regcache, I386_EBP_REGNUM, buf); 237 238 /* MarkK wrote: This "+ 8" is all over the place: 239 (i386_frame_this_id, i386_sigtramp_frame_this_id, 240 i386_dummy_id). It's there, since all frame unwinders for 241 a given target have to agree (within a certain margin) on the 242 definition of the stack address of a frame. Otherwise frame id 243 comparison might not work correctly. Since DWARF2/GCC uses the 244 stack address *before* the function call as a frame's CFA. On 245 the i386, when %ebp is used as a frame pointer, the offset 246 between the contents %ebp and the CFA as defined by GCC. */ 247 return sp + 8; 248} 249 250static void 251i386_darwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 252{ 253 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 254 255 /* We support the SSE registers. */ 256 tdep->num_xmm_regs = I386_NUM_XREGS - 1; 257 set_gdbarch_num_regs (gdbarch, I386_SSE_NUM_REGS); 258 259 dwarf2_frame_set_signal_frame_p (gdbarch, darwin_dwarf_signal_frame_p); 260 set_gdbarch_push_dummy_call (gdbarch, i386_darwin_push_dummy_call); 261 262 tdep->struct_return = reg_struct_return; 263 264 tdep->sigtramp_p = i386_sigtramp_p; 265 tdep->sigcontext_addr = i386_darwin_sigcontext_addr; 266 tdep->sc_reg_offset = i386_darwin_thread_state_reg_offset; 267 tdep->sc_num_regs = i386_darwin_thread_state_num_regs; 268 269 tdep->jb_pc_offset = 48; 270 271 /* Although the i387 extended floating-point has only 80 significant 272 bits, a `long double' actually takes up 128, probably to enforce 273 alignment. */ 274 set_gdbarch_long_double_bit (gdbarch, 128); 275 276 set_solib_ops (gdbarch, &darwin_so_ops); 277} 278 279static enum gdb_osabi 280i386_mach_o_osabi_sniffer (bfd *abfd) 281{ 282 if (!bfd_check_format (abfd, bfd_object)) 283 return GDB_OSABI_UNKNOWN; 284 285 if (bfd_get_arch (abfd) == bfd_arch_i386) 286 return GDB_OSABI_DARWIN; 287 288 return GDB_OSABI_UNKNOWN; 289} 290 291void 292_initialize_i386_darwin_tdep (void) 293{ 294 gdbarch_register_osabi_sniffer (bfd_arch_unknown, bfd_target_mach_o_flavour, 295 i386_mach_o_osabi_sniffer); 296 297 gdbarch_register_osabi (bfd_arch_i386, bfd_mach_i386_i386, 298 GDB_OSABI_DARWIN, i386_darwin_init_abi); 299} 300