/* Darwin support for GDB, the GNU debugger. Copyright (C) 1997-2022 Free Software Foundation, Inc. Contributed by Apple Computer, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #include "defs.h" #include "frame.h" #include "inferior.h" #include "gdbcore.h" #include "target.h" #include "symtab.h" #include "regcache.h" #include "objfiles.h" #include "i387-tdep.h" #include "i386-tdep.h" #include "osabi.h" #include "ui-out.h" #include "i386-darwin-tdep.h" #include "solib.h" #include "solib-darwin.h" #include "dwarf2/frame.h" #include /* Offsets into the struct i386_thread_state where we'll find the saved regs. From and i386-tdep.h. */ int i386_darwin_thread_state_reg_offset[] = { 0 * 4, /* EAX */ 2 * 4, /* ECX */ 3 * 4, /* EDX */ 1 * 4, /* EBX */ 7 * 4, /* ESP */ 6 * 4, /* EBP */ 5 * 4, /* ESI */ 4 * 4, /* EDI */ 10 * 4, /* EIP */ 9 * 4, /* EFLAGS */ 11 * 4, /* CS */ 8 * 4, /* SS */ 12 * 4, /* DS */ 13 * 4, /* ES */ 14 * 4, /* FS */ 15 * 4 /* GS */ }; const int i386_darwin_thread_state_num_regs = ARRAY_SIZE (i386_darwin_thread_state_reg_offset); /* Assuming THIS_FRAME is a Darwin sigtramp routine, return the address of the associated sigcontext structure. */ static CORE_ADDR i386_darwin_sigcontext_addr (struct frame_info *this_frame) { struct gdbarch *gdbarch = get_frame_arch (this_frame); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); CORE_ADDR bp; CORE_ADDR si; gdb_byte buf[4]; get_frame_register (this_frame, I386_EBP_REGNUM, buf); bp = extract_unsigned_integer (buf, 4, byte_order); /* A pointer to the ucontext is passed as the fourth argument to the signal handler. */ read_memory (bp + 24, buf, 4); si = extract_unsigned_integer (buf, 4, byte_order); /* The pointer to mcontext is at offset 28. */ read_memory (si + 28, buf, 4); /* First register (eax) is at offset 12. */ return extract_unsigned_integer (buf, 4, byte_order) + 12; } /* Return true if the PC of THIS_FRAME is in a signal trampoline which may have DWARF-2 CFI. On Darwin, signal trampolines have DWARF-2 CFI but it has only one FDE that covers only the indirect call to the user handler. Without this function, the frame is recognized as a normal frame which is not expected. */ int darwin_dwarf_signal_frame_p (struct gdbarch *gdbarch, struct frame_info *this_frame) { return i386_sigtramp_p (this_frame); } /* Check whether TYPE is a 128-bit vector (__m128, __m128d or __m128i). */ static int i386_m128_p (struct type *type) { return (type->code () == TYPE_CODE_ARRAY && type->is_vector () && type->length () == 16); } /* Return the alignment for TYPE when passed as an argument. */ static int i386_darwin_arg_type_alignment (struct type *type) { type = check_typedef (type); /* According to Mac OS X ABI document (passing arguments): 6. The caller places 64-bit vectors (__m64) on the parameter area, aligned to 8-byte boundaries. 7. [...] The caller aligns 128-bit vectors in the parameter area to 16-byte boundaries. */ if (type->code () == TYPE_CODE_ARRAY && type->is_vector ()) return type->length (); /* 4. The caller places all the fields of structures (or unions) with no vector elements in the parameter area. These structures are 4-byte aligned. 5. The caller places structures with vector elements on the stack, 16-byte aligned. */ if (type->code () == TYPE_CODE_STRUCT || type->code () == TYPE_CODE_UNION) { int i; int res = 4; for (i = 0; i < type->num_fields (); i++) { int align = i386_darwin_arg_type_alignment (type->field (i).type ()); res = std::max (res, align); } return res; } /* 2. The caller aligns nonvector arguments to 4-byte boundaries. */ return 4; } static CORE_ADDR i386_darwin_push_dummy_call (struct gdbarch *gdbarch, struct value *function, struct regcache *regcache, CORE_ADDR bp_addr, int nargs, struct value **args, CORE_ADDR sp, function_call_return_method return_method, CORE_ADDR struct_addr) { i386_gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); gdb_byte buf[4]; int i; int write_pass; /* Determine the total space required for arguments and struct return address in a first pass, then push arguments in a second pass. */ for (write_pass = 0; write_pass < 2; write_pass++) { int args_space = 0; int num_m128 = 0; if (return_method == return_method_struct) { if (write_pass) { /* Push value address. */ store_unsigned_integer (buf, 4, byte_order, struct_addr); write_memory (sp, buf, 4); } args_space += 4; } for (i = 0; i < nargs; i++) { struct type *arg_type = value_enclosing_type (args[i]); if (i386_m128_p (arg_type) && num_m128 < 4) { if (write_pass) { const gdb_byte *val = value_contents_all (args[i]).data (); regcache->raw_write (I387_MM0_REGNUM(tdep) + num_m128, val); } num_m128++; } else { args_space = align_up (args_space, i386_darwin_arg_type_alignment (arg_type)); if (write_pass) write_memory (sp + args_space, value_contents_all (args[i]).data (), arg_type->length ()); /* The System V ABI says that: "An argument's size is increased, if necessary, to make it a multiple of [32-bit] words. This may require tail padding, depending on the size of the argument." This makes sure the stack stays word-aligned. */ args_space += align_up (arg_type->length (), 4); } } /* Darwin i386 ABI: 1. The caller ensures that the stack is 16-byte aligned at the point of the function call. */ if (!write_pass) sp = align_down (sp - args_space, 16); } /* Store return address. */ sp -= 4; store_unsigned_integer (buf, 4, byte_order, bp_addr); write_memory (sp, buf, 4); /* Finally, update the stack pointer... */ store_unsigned_integer (buf, 4, byte_order, sp); regcache->cooked_write (I386_ESP_REGNUM, buf); /* ...and fake a frame pointer. */ regcache->cooked_write (I386_EBP_REGNUM, buf); /* MarkK wrote: This "+ 8" is all over the place: (i386_frame_this_id, i386_sigtramp_frame_this_id, i386_dummy_id). It's there, since all frame unwinders for a given target have to agree (within a certain margin) on the definition of the stack address of a frame. Otherwise frame id comparison might not work correctly. Since DWARF2/GCC uses the stack address *before* the function call as a frame's CFA. On the i386, when %ebp is used as a frame pointer, the offset between the contents %ebp and the CFA as defined by GCC. */ return sp + 8; } static void i386_darwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { i386_gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); /* We support the SSE registers. */ tdep->num_xmm_regs = I386_NUM_XREGS - 1; set_gdbarch_num_regs (gdbarch, I386_SSE_NUM_REGS); dwarf2_frame_set_signal_frame_p (gdbarch, darwin_dwarf_signal_frame_p); set_gdbarch_push_dummy_call (gdbarch, i386_darwin_push_dummy_call); tdep->struct_return = reg_struct_return; tdep->sigtramp_p = i386_sigtramp_p; tdep->sigcontext_addr = i386_darwin_sigcontext_addr; tdep->sc_reg_offset = i386_darwin_thread_state_reg_offset; tdep->sc_num_regs = i386_darwin_thread_state_num_regs; tdep->jb_pc_offset = 48; /* Although the i387 extended floating-point has only 80 significant bits, a `long double' actually takes up 128, probably to enforce alignment. */ set_gdbarch_long_double_bit (gdbarch, 128); set_gdbarch_so_ops (gdbarch, &darwin_so_ops); } static enum gdb_osabi i386_mach_o_osabi_sniffer (bfd *abfd) { if (!bfd_check_format (abfd, bfd_object)) return GDB_OSABI_UNKNOWN; if (bfd_get_arch (abfd) == bfd_arch_i386) return GDB_OSABI_DARWIN; return GDB_OSABI_UNKNOWN; } void _initialize_i386_darwin_tdep (); void _initialize_i386_darwin_tdep () { gdbarch_register_osabi_sniffer (bfd_arch_unknown, bfd_target_mach_o_flavour, i386_mach_o_osabi_sniffer); gdbarch_register_osabi (bfd_arch_i386, bfd_mach_i386_i386, GDB_OSABI_DARWIN, i386_darwin_init_abi); }