gdb/i386-darwin-tdep.c - gdb

Global variables defined

Functions defined

Source code

  1. /* Darwin support for GDB, the GNU debugger.
  2.    Copyright (C) 1997-2015 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/>.  */

  21. #include "defs.h"
  22. #include "frame.h"
  23. #include "inferior.h"
  24. #include "gdbcore.h"
  25. #include "target.h"
  26. #include "floatformat.h"
  27. #include "symtab.h"
  28. #include "regcache.h"
  29. #include "libbfd.h"
  30. #include "objfiles.h"

  32. #include "i387-tdep.h"
  33. #include "i386-tdep.h"
  34. #include "osabi.h"
  35. #include "ui-out.h"
  36. #include "i386-darwin-tdep.h"
  37. #include "solib.h"
  38. #include "solib-darwin.h"
  39. #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[] =
  44. {
  45.    0 * 4,   /* EAX */
  46.    2 * 4,   /* ECX */
  47.    3 * 4,   /* EDX */
  48.    1 * 4,   /* EBX */
  49.    7 * 4,   /* ESP */
  50.    6 * 4,   /* EBP */
  51.    5 * 4,   /* ESI */
  52.    4 * 4,   /* EDI */
  53.   10 * 4,   /* EIP */
  54.    9 * 4,   /* EFLAGS */
  55.   11 * 4,   /* CS */
  56.    8 * 4,   /* SS */
  57.   12 * 4,   /* DS */
  58.   13 * 4,   /* ES */
  59.   14 * 4,   /* FS */
  60.   15 * 4    /* GS */
  61. };

  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.  */

  69. static CORE_ADDR
  70. ‌i386_darwin_sigcontext_addr (struct frame_info *this_frame)
  71. {
  72.   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  73.   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  74.   CORE_ADDR bp;
  75.   CORE_ADDR si;
  76.   gdb_byte buf[4];

  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;
  91. }

  93. /* Return true if the PC of THIS_FRAME is in a signal trampoline which
  94.    may have DWARF-2 CFI.

  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
  99.    not expected.  */

  101. int
  102. ‌darwin_dwarf_signal_frame_p (struct gdbarch *gdbarch,
  103.                              struct frame_info *this_frame)
  104. {
  105.   return i386_sigtramp_p (this_frame);
  106. }

  108. /* Check wether TYPE is a 128-bit vector (__m128, __m128d or __m128i).  */

  110. static int
  111. ‌i386_m128_p (struct type *type)
  112. {
  113.   return (TYPE_CODE (type) == TYPE_CODE_ARRAY && TYPE_VECTOR (type)
  114.           && TYPE_LENGTH (type) == 16);
  115. }

  117. /* Return the alignment for TYPE when passed as an argument.  */

  119. static int
  120. ‌i386_darwin_arg_type_alignment (struct type *type)
  121. {
  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
  132.          aligned.
  133.      5.  The caller places structures with vector elements on the stack,
  134.          16-byte aligned.  */
  135.   if (TYPE_CODE (type) == TYPE_CODE_STRUCT
  136.       || TYPE_CODE (type) == TYPE_CODE_UNION)
  137.     {
  138.       int i;
  139.       int res = 4;
  140.       for (i = 0; i < TYPE_NFIELDS (type); i++)
  141.         res = max (res,
  142.                    i386_darwin_arg_type_alignment (TYPE_FIELD_TYPE (type, i)));
  143.       return res;
  144.     }
  145.   /* 2.  The caller aligns nonvector arguments to 4-byte boundaries.  */
  146.   return 4;
  147. }

  149. static CORE_ADDR
  150. ‌i386_darwin_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
  151.                              struct regcache *regcache, CORE_ADDR bp_addr,
  152.                              int nargs, struct value **args, CORE_ADDR sp,
  153.                              int struct_return, CORE_ADDR struct_addr)
  154. {
  155.   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  156.   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  157.   gdb_byte buf[4];
  158.   int i;
  159.   int write_pass;

  161.   /* Determine the total space required for arguments and struct
  162.      return address in a first pass, then push arguments in a second pass.  */

  164.   for (write_pass = 0; write_pass < 2; write_pass++)
  165.     {
  166.       int args_space = 0;
  167.       int num_m128 = 0;

  169.       if (struct_return)
  170.         {
  171.           if (write_pass)
  172.             {
  173.               /* Push value address.  */
  174.               store_unsigned_integer (buf, 4, byte_order, struct_addr);
  175.               write_memory (sp, buf, 4);
  176.             }
  177.           args_space += 4;
  178.         }

  180.       for (i = 0; i < nargs; i++)
  181.         {
  182.           struct type *arg_type = value_enclosing_type (args[i]);

  184.           if (i386_m128_p (arg_type) && num_m128 < 4)
  185.             {
  186.               if (write_pass)
  187.                 {
  188.                   const gdb_byte *val = value_contents_all (args[i]);
  189.                   regcache_raw_write
  190.                     (regcache, I387_MM0_REGNUM(tdep) + num_m128, val);
  191.                 }
  192.               num_m128++;
  193.             }
  194.           else
  195.             {
  196.               args_space = align_up (args_space,
  197.                                      i386_darwin_arg_type_alignment (arg_type));
  198.               if (write_pass)
  199.                 write_memory (sp + args_space,
  200.                               value_contents_all (args[i]),
  201.                               TYPE_LENGTH (arg_type));

  203.               /* The System V ABI says that:

  205.                  "An argument's size is increased, if necessary, to make it a
  206.                  multiple of [32-bit] words.  This may require tail padding,
  207.                  depending on the size of the argument."

  209.                  This makes sure the stack stays word-aligned.  */
  210.               args_space += align_up (TYPE_LENGTH (arg_type), 4);
  211.             }
  212.         }

  214.       /* Darwin i386 ABI:
  215.          1.  The caller ensures that the stack is 16-byte aligned at the point
  216.              of the function call.  */
  217.       if (!write_pass)
  218.         sp = align_down (sp - args_space, 16);
  219.     }

  221.   /* Store return address.  */
  222.   sp -= 4;
  223.   store_unsigned_integer (buf, 4, byte_order, bp_addr);
  224.   write_memory (sp, buf, 4);

  226.   /* Finally, update the stack pointer...  */
  227.   store_unsigned_integer (buf, 4, byte_order, sp);
  228.   regcache_cooked_write (regcache, I386_ESP_REGNUM, buf);

  230.   /* ...and fake a frame pointer.  */
  231.   regcache_cooked_write (regcache, I386_EBP_REGNUM, buf);

  233.   /* MarkK wrote: This "+ 8" is all over the place:
  234.      (i386_frame_this_id, i386_sigtramp_frame_this_id,
  235.      i386_dummy_id).  It's there, since all frame unwinders for
  236.      a given target have to agree (within a certain margin) on the
  237.      definition of the stack address of a frame.  Otherwise frame id
  238.      comparison might not work correctly.  Since DWARF2/GCC uses the
  239.      stack address *before* the function call as a frame's CFA.  On
  240.      the i386, when %ebp is used as a frame pointer, the offset
  241.      between the contents %ebp and the CFA as defined by GCC.  */
  242.   return sp + 8;
  243. }

  245. static void
  246. ‌i386_darwin_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
  247. {
  248.   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  250.   /* We support the SSE registers.  */
  251.   tdep->num_xmm_regs = I386_NUM_XREGS - 1;
  252.   set_gdbarch_num_regs (gdbarch, I386_SSE_NUM_REGS);

  254.   dwarf2_frame_set_signal_frame_p (gdbarch, darwin_dwarf_signal_frame_p);
  255.   set_gdbarch_push_dummy_call (gdbarch, i386_darwin_push_dummy_call);

  257.   tdep->struct_return = reg_struct_return;

  259.   tdep->sigtramp_p = i386_sigtramp_p;
  260.   tdep->sigcontext_addr = i386_darwin_sigcontext_addr;
  261.   tdep->sc_reg_offset = i386_darwin_thread_state_reg_offset;
  262.   tdep->sc_num_regs = i386_darwin_thread_state_num_regs;

  264.   tdep->jb_pc_offset = 48;

  266.   /* Although the i387 extended floating-point has only 80 significant
  267.      bits, a `long double' actually takes up 128, probably to enforce
  268.      alignment.  */
  269.   set_gdbarch_long_double_bit (gdbarch, 128);

  271.   set_solib_ops (gdbarch, &darwin_so_ops);
  272. }

  274. static enum gdb_osabi
  275. ‌i386_mach_o_osabi_sniffer (bfd *abfd)
  276. {
  277.   if (!bfd_check_format (abfd, bfd_object))
  278.     return GDB_OSABI_UNKNOWN;

  280.   if (bfd_get_arch (abfd) == bfd_arch_i386)
  281.     return GDB_OSABI_DARWIN;

  283.   return GDB_OSABI_UNKNOWN;
  284. }

  286. /* -Wmissing-prototypes */
  287. extern initialize_file_ftype _initialize_i386_darwin_tdep;

  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);

  295.   gdbarch_register_osabi (bfd_arch_i386, bfd_mach_i386_i386,
  296.                           GDB_OSABI_DARWIN, i386_darwin_init_abi);
  297. }