1/* 32-bit ELF for the WebAssembly target
2   Copyright (C) 2017-2022 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
28static 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
62static reloc_howto_type *
63elf32_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
81static reloc_howto_type *
82elf32_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
97static reloc_howto_type *
98elf32_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
119static bool
120elf32_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"
158