bfd/elf32-wasm32.c

   1 /* 32-bit ELF for the WebAssembly target
   2    Copyright (C) 2017-2021 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,
  19    Boston, MA 02110-1301, USA.  */
  20
  21 #include "sysdep.h"
  22 #include "bfd.h"
  23 #include "libbfd.h"
  24 #include "elf-bfd.h"
  25 #include "libiberty.h"
  26 #include "elf/wasm32.h"
  27
  28 static reloc_howto_type elf32_wasm32_howto_table[] =
  29 {
  30   HOWTO (R_WASM32_NONE,         /* type */
  31          0,                     /* rightshift */
  32          3,                     /* size (0 = byte, 1 = short, 2 = long) */
  33          0,                     /* bitsize */
  34          false,                 /* pc_relative */
  35          0,                     /* bitpos */
  36          complain_overflow_dont,/* complain_on_overflow */
  37          bfd_elf_generic_reloc, /* special_function */
  38          "R_WASM32_NONE",       /* name */
  39          false,                 /* partial_inplace */
  40          0,                     /* src_mask */
  41          0,                     /* dst_mask */
  42          false),                /* pcrel_offset */
  43
  44   /* 32 bit absolute */
  45   HOWTO (R_WASM32_32,           /* type */
  46          0,                     /* rightshift */
  47          2,                     /* size (0 = byte, 1 = short, 2 = long) */
  48          32,                    /* bitsize */
  49          false,                 /* pc_relative */
  50          0,                     /* bitpos */
  51          complain_overflow_bitfield,/* complain_on_overflow */
  52          bfd_elf_generic_reloc, /* special_function */
  53          "R_WASM32_32", /* name */
  54          false,                 /* partial_inplace */
  55          0xffffffff,            /* src_mask */
  56          0xffffffff,            /* dst_mask */
  57          false),                /* pcrel_offset */
  58 };
  59
  60 /* Look up the relocation CODE.  */
  61
  62 static reloc_howto_type *
  63 elf32_wasm32_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
  64                                 bfd_reloc_code_real_type code)
  65 {
  66   switch (code)
  67     {
  68     case BFD_RELOC_NONE:
  69       return &elf32_wasm32_howto_table[R_WASM32_NONE];
  70     case BFD_RELOC_32:
  71       return &elf32_wasm32_howto_table[R_WASM32_32];
  72     default:
  73       break;
  74     }
  75
  76   return NULL;
  77 }
  78
  79 /* Look up the relocation R_NAME.  */
  80
  81 static reloc_howto_type *
  82 elf32_wasm32_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
  83                                 const char *r_name)
  84 {
  85   unsigned int i;
  86
  87   for (i = 0; i < ARRAY_SIZE (elf32_wasm32_howto_table); i++)
  88     if (elf32_wasm32_howto_table[i].name != NULL
  89         && strcasecmp (elf32_wasm32_howto_table[i].name, r_name) == 0)
  90       return &elf32_wasm32_howto_table[i];
  91
  92   return NULL;
  93 }
  94
  95 /* Look up the relocation R_TYPE.  */
  96
  97 static reloc_howto_type *
  98 elf32_wasm32_rtype_to_howto (bfd *abfd, unsigned r_type)
  99 {
 100   unsigned int i = r_type;
 101
 102   if (i >= ARRAY_SIZE (elf32_wasm32_howto_table))
 103     {
 104       /* xgettext:c-format */
 105       _bfd_error_handler (_("%pB: unsupported relocation type %#x"),
 106                           abfd, r_type);
 107       bfd_set_error (bfd_error_bad_value);
 108       return NULL;
 109     }
 110
 111   if (elf32_wasm32_howto_table[i].type != r_type)
 112     return NULL;
 113
 114   return elf32_wasm32_howto_table + i;
 115 }
 116
 117 /* Translate the ELF-internal relocation RELA into CACHE_PTR.  */
 118
 119 static bool
 120 elf32_wasm32_info_to_howto_rela (bfd *abfd,
 121                                 arelent *cache_ptr,
 122                                 Elf_Internal_Rela *dst)
 123 {
 124   unsigned int r_type = ELF32_R_TYPE (dst->r_info);
 125
 126   cache_ptr->howto = elf32_wasm32_rtype_to_howto (abfd, r_type);
 127   return cache_ptr->howto != NULL;
 128 }
 129
 130 #define ELF_ARCH                bfd_arch_wasm32
 131 #define ELF_TARGET_ID           EM_WEBASSEMBLY
 132 #define ELF_MACHINE_CODE        EM_WEBASSEMBLY
 133 /* FIXME we don't have paged executables, see:
 134    https://github.com/pipcet/binutils-gdb/issues/4  */
 135 #define ELF_MAXPAGESIZE         4096
 136
 137 #define TARGET_LITTLE_SYM       wasm32_elf32_vec
 138 #define TARGET_LITTLE_NAME      "elf32-wasm32"
 139
 140 #define elf_backend_can_gc_sections     1
 141 #define elf_backend_rela_normal         1
 142 /* For testing. */
 143 #define elf_backend_want_dynrelro       1
 144
 145 #define elf_info_to_howto               elf32_wasm32_info_to_howto_rela
 146 #define elf_info_to_howto_rel           NULL
 147
 148 #define bfd_elf32_bfd_reloc_type_lookup elf32_wasm32_reloc_type_lookup
 149 #define bfd_elf32_bfd_reloc_name_lookup elf32_wasm32_reloc_name_lookup
 150
 151 #define ELF_DYNAMIC_INTERPRETER  "/sbin/elf-dynamic-interpreter.so"
 152
 153 #define elf_backend_want_got_plt        1
 154 #define elf_backend_plt_readonly        1
 155 #define elf_backend_got_header_size     0
 156
 157 #include "elf32-target.h"