include/mach-o/unwind.h

   1 /* Mach-O compact unwind encoding.
   2    Copyright (C) 2014 Free Software Foundation, Inc.
   3
   4    This file is part of BFD, the Binary File Descriptor library.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #ifndef _MACH_O_UNWIND_H
  22 #define _MACH_O_UNWIND_H
  23
  24 /* Encodings bits for all cpus.  */
  25 #define MACH_O_UNWIND_IS_NOT_FUNCTION_START 0x80000000
  26 #define MACH_O_UNWIND_HAS_LSDA              0x40000000
  27 #define MACH_O_UNWIND_PERSONALITY_MASK      0x30000000
  28 #define MACH_O_UNWIND_PERSONALITY_SHIFT     28
  29
  30 /* Encodings for x86-64.  */
  31
  32 /* Kind of encoding (4 bits).  */
  33 #define MACH_O_UNWIND_X86_64_MODE_MASK       0x0f000000
  34
  35 /* Frame is RBP based, using the standard sequence: push %rbp; mov %rsp, %rbp.
  36    Non-volatile registers must be saved in the stack starting at %rbp-8 to
  37    %rbp-2040 (offset is encoded in offset bits * 8).  Registers saved are
  38    encoded in registers bits, 3 bits per register.  */
  39 #define MACH_O_UNWIND_X86_64_MODE_RBP_FRAME  0x01000000
  40 #define  MACH_O_UNWIND_X86_64_RBP_FRAME_REGSITERS 0x00007FFF
  41 #define  MACH_O_UNWIND_X86_64_RBP_FRAME_OFFSET    0x00FF0000
  42
  43 /* Frameless function, with a small stack size.  */
  44 #define MACH_O_UNWIND_X86_64_MODE_STACK_IMMD 0x02000000
  45 #define  MACH_O_UNWIND_X86_64_FRAMELESS_STACK_SIZE      0x00FF0000
  46 #define  MACH_O_UNWIND_X86_64_FRAMELESS_REG_COUNT       0x00001C00
  47 #define  MACH_O_UNWIND_X86_64_FRAMELESS_REG_PERMUTATION 0x000003FF
  48
  49 /* Frameless function, with a larger stack size. The stack size is the sum
  50    of the X in subq $X,%rsp (address of X is at function + stack size bits)
  51    and stack adjust.  */
  52 #define MACH_O_UNWIND_X86_64_MODE_STACK_IND          0x03000000
  53 #define  MACH_O_UNWIND_X86_64_FRAMELESS_STACK_ADJUST 0x0000E000
  54
  55 /* Use dwarf.  */
  56 #define MACH_O_UNWIND_X86_64_MODE_DWARF      0x04000000
  57 #define  MACH_O_UNWIND_X86_64_DWARF_SECTION_OFFSET 0x00ffffff
  58
  59 /* Registers.  */
  60 #define MACH_O_UNWIND_X86_64_REG_NONE 0
  61 #define MACH_O_UNWIND_X86_64_REG_RBX 1
  62 #define MACH_O_UNWIND_X86_64_REG_R12 2
  63 #define MACH_O_UNWIND_X86_64_REG_R13 3
  64 #define MACH_O_UNWIND_X86_64_REG_R14 4
  65 #define MACH_O_UNWIND_X86_64_REG_R15 5
  66 #define MACH_O_UNWIND_X86_64_REG_RBP 6
  67
  68 /* Encodings for x86 (almot the same as x86-64).  */
  69
  70 /* Kind of encoding (4 bits).  */
  71 #define MACH_O_UNWIND_X86_MODE_MASK       0x0f000000
  72
  73 /* Frame is EBP based, using the standard sequence: push %ebp; mov %esp, %ebp.
  74    Non-volatile registers must be saved in the stack starting at %ebp-4 to
  75    %ebp-240 (offset is encoded in offset bits * 4).  Registers saved are
  76    encoded in registers bits, 3 bits per register.  */
  77 #define MACH_O_UNWIND_X86_MODE_EBP_FRAME  0x01000000
  78 #define  MACH_O_UNWIND_X86_EBP_FRAME_REGSITERS 0x00007FFF
  79 #define  MACH_O_UNWIND_X86_EBP_FRAME_OFFSET    0x00FF0000
  80
  81 /* Frameless function, with a small stack size.  */
  82 #define MACH_O_UNWIND_X86_MODE_STACK_IMMD 0x02000000
  83 #define  MACH_O_UNWIND_X86_FRAMELESS_STACK_SIZE      0x00FF0000
  84 #define  MACH_O_UNWIND_X86_FRAMELESS_REG_COUNT       0x00001C00
  85 #define  MACH_O_UNWIND_X86_FRAMELESS_REG_PERMUTATION 0x000003FF
  86
  87 /* Frameless function, with a larger stack size. The stack size is the sum
  88    of the X in subq $X,%esp (address of X is at function + stack size bits)
  89    and stack adjust.  */
  90 #define MACH_O_UNWIND_X86_MODE_STACK_IND          0x03000000
  91 #define  MACH_O_UNWIND_X86_FRAMELESS_STACK_ADJUST 0x0000E000
  92
  93 /* Use dwarf.  */
  94 #define MACH_O_UNWIND_X86_MODE_DWARF      0x04000000
  95 #define  MACH_O_UNWIND_X86_DWARF_SECTION_OFFSET 0x00ffffff
  96
  97 /* Registers.  */
  98 #define MACH_O_UNWIND_X86_REG_NONE 0
  99 #define MACH_O_UNWIND_X86_REG_EBX 1
 100 #define MACH_O_UNWIND_X86_REG_ECX 2
 101 #define MACH_O_UNWIND_X86_REG_EDX 3
 102 #define MACH_O_UNWIND_X86_REG_EDI 4
 103 #define MACH_O_UNWIND_X86_REG_ESI 5
 104 #define MACH_O_UNWIND_X86_REG_EBP 6
 105
 106 /* Entry in object file (in __LD,__compact_unwind section).  */
 107
 108 struct mach_o_compact_unwind_32
 109 {
 110   unsigned char start[4];
 111   unsigned char length[4];
 112   unsigned char encoding[4];
 113   unsigned char personality[4];
 114   unsigned char lsda[4];
 115 };
 116
 117 struct mach_o_compact_unwind_64
 118 {
 119   unsigned char start[8];
 120   unsigned char length[4];
 121   unsigned char encoding[4];
 122   unsigned char personnality[8];
 123   unsigned char lsda[8];
 124 };
 125
 126 /* Header in images (in __TEXT,__unwind_info).  */
 127
 128 #define MACH_O_UNWIND_SECTION_VERSION 1 /* Current verion in header.  */
 129 struct mach_o_unwind_info_header
 130 {
 131   unsigned char version[4];     /* Currently MACH_O_UNWIND_SECTION_VERSION. */
 132   unsigned char encodings_array_offset[4];
 133   unsigned char encodings_array_count[4];
 134   unsigned char personality_array_offset[4];
 135   unsigned char personality_array_count[4];
 136   unsigned char index_offset[4];
 137   unsigned char index_count[4];
 138   /* Followed by:
 139      - encodings array
 140        These are the encodings shared, for index < encoding_array_count
 141      - personality array
 142        count given by personality_array_count
 143      - index entries
 144        count given by index_count
 145      - lsda index entries
 146        last offset given by lsda offset of last index_entry.
 147   */
 148 };
 149
 150 struct mach_o_unwind_index_entry
 151 {
 152   unsigned char function_offset[4];
 153   unsigned char second_level_offset[4];
 154   unsigned char lsda_index_offset[4];
 155 };
 156
 157 struct mach_o_unwind_lsda_index_entry
 158 {
 159   unsigned char function_offset[4];
 160   unsigned char lsda_offset[4];
 161 };
 162
 163 /* Second level index pages.  */
 164
 165 #define MACH_O_UNWIND_SECOND_LEVEL_REGULAR 2
 166 struct mach_o_unwind_regular_second_level_page_header
 167 {
 168   unsigned char kind[4];
 169   unsigned char entry_page_offset[2];
 170   unsigned char entry_count[2];
 171   /* Array of entries.  */
 172 };
 173
 174 struct mach_o_unwind_regular_second_level_entry
 175 {
 176   unsigned char function_offset[4];
 177   unsigned char encoding[4];
 178 };
 179
 180 #define MACH_O_UNWIND_SECOND_LEVEL_COMPRESSED 3
 181 struct mach_o_unwind_compressed_second_level_page_header
 182 {
 183   unsigned char kind[4];
 184   unsigned char entry_page_offset[2];
 185   unsigned char entry_count[2];
 186   unsigned char encodings_offset[2];
 187   unsigned char encodings_count[2];
 188   /* Followed by entries array (one word, see below).  */
 189   /* Followed by (non-common) encodings array.  */
 190 };
 191
 192 /* Compressed entries are one word, containing function offset and encoding
 193    index.  */
 194 #define MACH_O_UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(en) \
 195    ((en) & 0x00FFFFFF)
 196 #define MACH_O_UNWIND_INFO_COMPRESSED_ENTRY_ENCODING_INDEX(en) \
 197    (((en) >> 24) & 0xFF)
 198
 199 #endif /* _MACH_O_UNWIND_H */