1 /* Darwin support for GDB, the GNU debugger.
2 Copyright (C) 1997-2017 Free Software Foundation, Inc.
4 Contributed by Apple Computer, Inc.
6 This file is part of GDB.
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.
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.
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/>. */
26 #include "floatformat.h"
31 #include "i387-tdep.h"
32 #include "i386-tdep.h"
35 #include "i386-darwin-tdep.h"
37 #include "solib-darwin.h"
38 #include "dwarf2-frame.h"
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[] =
63 const int i386_darwin_thread_state_num_regs =
64 ARRAY_SIZE (i386_darwin_thread_state_reg_offset);
66 /* Assuming THIS_FRAME is a Darwin sigtramp routine, return the
67 address of the associated sigcontext structure. */
70 i386_darwin_sigcontext_addr (struct frame_info *this_frame)
72 struct gdbarch *gdbarch = get_frame_arch (this_frame);
73 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
78 get_frame_register (this_frame, I386_EBP_REGNUM, buf);
79 bp = extract_unsigned_integer (buf, 4, byte_order);
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);
86 /* The pointer to mcontext is at offset 28. */
87 read_memory (si + 28, buf, 4);
89 /* First register (eax) is at offset 12. */
90 return extract_unsigned_integer (buf, 4, byte_order) + 12;
93 /* Return true if the PC of THIS_FRAME is in a signal trampoline which
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
102 darwin_dwarf_signal_frame_p (struct gdbarch *gdbarch,
103 struct frame_info *this_frame)
105 return i386_sigtramp_p (this_frame);
108 /* Check wether TYPE is a 128-bit vector (__m128, __m128d or __m128i). */
111 i386_m128_p (struct type *type)
113 return (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type)
114 && TYPE_LENGTH (type) == 16);
117 /* Return the alignment for TYPE when passed as an argument. */
120 i386_darwin_arg_type_alignment (struct type *type)
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
133 5. The caller places structures with vector elements on the stack,
135 if (TYPE_CODE (type) == TYPE_CODE_STRUCT
136 || TYPE_CODE (type) == TYPE_CODE_UNION)
140 for (i = 0; i < TYPE_NFIELDS (type); i++)
143 = i386_darwin_arg_type_alignment (TYPE_FIELD_TYPE (type, i));
145 res = std::max (res, align);
149 /* 2. The caller aligns nonvector arguments to 4-byte boundaries. */
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)
159 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
160 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
165 /* Determine the total space required for arguments and struct
166 return address in a first pass, then push arguments in a second pass. */
168 for (write_pass = 0; write_pass < 2; write_pass++)
177 /* Push value address. */
178 store_unsigned_integer (buf, 4, byte_order, struct_addr);
179 write_memory (sp, buf, 4);
184 for (i = 0; i < nargs; i++)
186 struct type *arg_type = value_enclosing_type (args[i]);
188 if (i386_m128_p (arg_type) && num_m128 < 4)
192 const gdb_byte *val = value_contents_all (args[i]);
194 (regcache, I387_MM0_REGNUM(tdep) + num_m128, val);
200 args_space = align_up (args_space,
201 i386_darwin_arg_type_alignment (arg_type));
203 write_memory (sp + args_space,
204 value_contents_all (args[i]),
205 TYPE_LENGTH (arg_type));
207 /* The System V ABI says that:
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."
213 This makes sure the stack stays word-aligned. */
214 args_space += align_up (TYPE_LENGTH (arg_type), 4);
219 1. The caller ensures that the stack is 16-byte aligned at the point
220 of the function call. */
222 sp = align_down (sp - args_space, 16);
225 /* Store return address. */
227 store_unsigned_integer (buf, 4, byte_order, bp_addr);
228 write_memory (sp, buf, 4);
230 /* Finally, update the stack pointer... */
231 store_unsigned_integer (buf, 4, byte_order, sp);
232 regcache_cooked_write (regcache, I386_ESP_REGNUM, buf);
234 /* ...and fake a frame pointer. */
235 regcache_cooked_write (regcache, I386_EBP_REGNUM, buf);
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. */
250 i386_darwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
252 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
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);
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);
261 tdep->struct_return = reg_struct_return;
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;
268 tdep->jb_pc_offset = 48;
270 /* Although the i387 extended floating-point has only 80 significant
271 bits, a `long double' actually takes up 128, probably to enforce
273 set_gdbarch_long_double_bit (gdbarch, 128);
275 set_solib_ops (gdbarch, &darwin_so_ops);
278 static enum gdb_osabi
279 i386_mach_o_osabi_sniffer (bfd *abfd)
281 if (!bfd_check_format (abfd, bfd_object))
282 return GDB_OSABI_UNKNOWN;
284 if (bfd_get_arch (abfd) == bfd_arch_i386)
285 return GDB_OSABI_DARWIN;
287 return GDB_OSABI_UNKNOWN;
291 _initialize_i386_darwin_tdep (void)
293 gdbarch_register_osabi_sniffer (bfd_arch_unknown, bfd_target_mach_o_flavour,
294 i386_mach_o_osabi_sniffer);
296 gdbarch_register_osabi (bfd_arch_i386, bfd_mach_i386_i386,
297 GDB_OSABI_DARWIN, i386_darwin_init_abi);