1 /* 32-bit ELF for the WebAssembly target
2 Copyright (C) 2017-2023 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 0, /* size */
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 4, /* size */
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"