ld -r doesn't need plugin for slim lto object
[deliverable/binutils-gdb.git] / gold / binary.cc
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1// binary.cc -- binary input files for gold
2
b90efa5b 3// Copyright (C) 2008-2015 Free Software Foundation, Inc.
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4// Written by Ian Lance Taylor <iant@google.com>.
5
6// This file is part of gold.
7
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.
12
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.
17
18// You should have received a copy of the GNU General Public License
19// along with this program; if not, write to the Free Software
20// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21// MA 02110-1301, USA.
22
23#include "gold.h"
24
25#include <cerrno>
26#include <cstring>
27#include "safe-ctype.h"
28
29#include "elfcpp.h"
30#include "stringpool.h"
31#include "fileread.h"
32#include "output.h"
33#include "binary.h"
34
35// Support for reading binary files as input. These become blobs in
36// the final output. These files are treated as though they have a
37// single .data section and define three symbols:
602b464e 38// _binary_FILENAME_start, _binary_FILENAME_end, _binary_FILENAME_size.
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39// The FILENAME is the name of the input file, with any
40// non-alphanumeric character changed to an underscore.
41
42// We implement this by creating an ELF file in memory.
43
44namespace gold
45{
46
47// class Binary_to_elf.
48
49Binary_to_elf::Binary_to_elf(elfcpp::EM machine, int size, bool big_endian,
50 const std::string& filename)
51 : elf_machine_(machine), size_(size), big_endian_(big_endian),
52 filename_(filename), data_(NULL), filesize_(0)
53{
54}
55
56Binary_to_elf::~Binary_to_elf()
57{
58 if (this->data_ != NULL)
59 delete[] this->data_;
60}
61
62// Given FILENAME, create a buffer which looks like an ELF file with
63// the contents of FILENAME as the contents of the only section. The
64// TASK parameters is mainly for debugging, and records who holds
65// locks.
66
67bool
68Binary_to_elf::convert(const Task* task)
69{
70 if (this->size_ == 32)
71 {
72 if (!this->big_endian_)
73 {
74#ifdef HAVE_TARGET_32_LITTLE
75 return this->sized_convert<32, false>(task);
76#else
77 gold_unreachable();
78#endif
79 }
80 else
81 {
82#ifdef HAVE_TARGET_32_BIG
83 return this->sized_convert<32, true>(task);
84#else
85 gold_unreachable();
86#endif
87 }
88 }
89 else if (this->size_ == 64)
90 {
91 if (!this->big_endian_)
92 {
93#ifdef HAVE_TARGET_64_LITTLE
94 return this->sized_convert<64, false>(task);
95#else
96 gold_unreachable();
97#endif
98 }
99 else
100 {
101#ifdef HAVE_TARGET_64_BIG
102 return this->sized_convert<64, true>(task);
103#else
104 gold_unreachable();
105#endif
106 }
107 }
108 else
109 gold_unreachable();
110}
111
112// We are going to create:
113// * The ELF file header.
114// * Five sections: null section, .data, .symtab, .strtab, .shstrtab
115// * The contents of the file.
116// * Four symbols: null, begin, end, size.
117// * Three symbol names.
118// * Four section names.
119
120template<int size, bool big_endian>
121bool
122Binary_to_elf::sized_convert(const Task* task)
123{
124 // Read the input file.
125
126 File_read f;
127 if (!f.open(task, this->filename_))
128 {
129 gold_error(_("cannot open %s: %s:"), this->filename_.c_str(),
130 strerror(errno));
131 return false;
132 }
133
134 section_size_type filesize = convert_to_section_size_type(f.filesize());
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135 const unsigned char* fileview;
136 if (filesize == 0)
137 fileview = NULL;
138 else
139 fileview = f.get_view(0, 0, filesize, false, false);
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140
141 unsigned int align;
142 if (size == 32)
143 align = 4;
144 else if (size == 64)
145 align = 8;
146 else
147 gold_unreachable();
148 section_size_type aligned_filesize = align_address(filesize, align);
149
150 // Build the stringpool for the symbol table.
151
152 std::string mangled_name = this->filename_;
153 for (std::string::iterator p = mangled_name.begin();
154 p != mangled_name.end();
155 ++p)
156 if (!ISALNUM(*p))
157 *p = '_';
158 mangled_name = "_binary_" + mangled_name;
159 std::string start_symbol_name = mangled_name + "_start";
160 std::string end_symbol_name = mangled_name + "_end";
161 std::string size_symbol_name = mangled_name + "_size";
162
163 Stringpool strtab;
164 strtab.add(start_symbol_name.c_str(), false, NULL);
165 strtab.add(end_symbol_name.c_str(), false, NULL);
166 strtab.add(size_symbol_name.c_str(), false, NULL);
167 strtab.set_string_offsets();
168
169 // Build the stringpool for the section name table.
170
171 Stringpool shstrtab;
172 shstrtab.add(".data", false, NULL);
173 shstrtab.add(".symtab", false, NULL);
174 shstrtab.add(".strtab", false, NULL);
175 shstrtab.add(".shstrtab", false, NULL);
176 shstrtab.set_string_offsets();
177
178 // Work out the size of the generated file, and the offsets of the
179 // various sections, and allocate a buffer.
180
181 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
182
183 size_t output_size = (elfcpp::Elf_sizes<size>::ehdr_size
184 + 5 * elfcpp::Elf_sizes<size>::shdr_size);
185 size_t data_offset = output_size;
186 output_size += aligned_filesize;
187 size_t symtab_offset = output_size;
188 output_size += 4 * sym_size;
189 size_t strtab_offset = output_size;
190 output_size += strtab.get_strtab_size();
191 size_t shstrtab_offset = output_size;
192 output_size += shstrtab.get_strtab_size();
193
194 unsigned char* buffer = new unsigned char[output_size];
195
196 // Write out the data.
197
198 unsigned char* pout = buffer;
199
200 this->write_file_header<size, big_endian>(&pout);
201
202 this->write_section_header<size, big_endian>("", &shstrtab, elfcpp::SHT_NULL,
203 0, 0, 0, 0, 0,
204 0, 0, &pout);
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205 // Having the section be named ".data", having it be writable, and
206 // giving it an alignment of 1 is because the GNU linker does it
207 // that way, and existing linker script expect it.
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208 this->write_section_header<size, big_endian>(".data", &shstrtab,
209 elfcpp::SHT_PROGBITS,
210 (elfcpp::SHF_ALLOC
211 | elfcpp::SHF_WRITE),
212 data_offset,
213 filesize, 0, 0,
f0b886e3 214 1, 0, &pout);
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215 this->write_section_header<size, big_endian>(".symtab", &shstrtab,
216 elfcpp::SHT_SYMTAB,
217 0, symtab_offset, 4 * sym_size,
218 3, 1, align, sym_size, &pout);
219 this->write_section_header<size, big_endian>(".strtab", &shstrtab,
220 elfcpp::SHT_STRTAB,
221 0, strtab_offset,
222 strtab.get_strtab_size(),
223 0, 0, 1, 0, &pout);
224 this->write_section_header<size, big_endian>(".shstrtab", &shstrtab,
225 elfcpp::SHT_STRTAB,
226 0, shstrtab_offset,
227 shstrtab.get_strtab_size(),
228 0, 0, 1, 0, &pout);
229
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230 if (filesize > 0)
231 {
232 memcpy(pout, fileview, filesize);
233 pout += filesize;
234 memset(pout, 0, aligned_filesize - filesize);
235 pout += aligned_filesize - filesize;
236 }
bc644c6c 237
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238 this->write_symbol<size, big_endian>("", &strtab, 0, 0, 0, &pout);
239 this->write_symbol<size, big_endian>(start_symbol_name, &strtab, 0, filesize,
240 1, &pout);
241 this->write_symbol<size, big_endian>(end_symbol_name, &strtab, filesize, 0,
242 1, &pout);
243 this->write_symbol<size, big_endian>(size_symbol_name, &strtab, filesize, 0,
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244 elfcpp::SHN_ABS, &pout);
245
246 strtab.write_to_buffer(pout, strtab.get_strtab_size());
247 pout += strtab.get_strtab_size();
248
249 shstrtab.write_to_buffer(pout, shstrtab.get_strtab_size());
250 pout += shstrtab.get_strtab_size();
251
252 gold_assert(static_cast<size_t>(pout - buffer) == output_size);
253
254 this->data_ = buffer;
255 this->filesize_ = output_size;
256
257 f.unlock(task);
258
259 return true;
260}
261
262// Write out the file header.
263
264template<int size, bool big_endian>
265void
266Binary_to_elf::write_file_header(unsigned char** ppout)
267{
268 elfcpp::Ehdr_write<size, big_endian> oehdr(*ppout);
269
270 unsigned char e_ident[elfcpp::EI_NIDENT];
271 memset(e_ident, 0, elfcpp::EI_NIDENT);
272 e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;
273 e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;
274 e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;
275 e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;
276 if (size == 32)
277 e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;
278 else if (size == 64)
279 e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;
280 else
281 gold_unreachable();
282 e_ident[elfcpp::EI_DATA] = (big_endian
283 ? elfcpp::ELFDATA2MSB
284 : elfcpp::ELFDATA2LSB);
285 e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
286 oehdr.put_e_ident(e_ident);
287
288 oehdr.put_e_type(elfcpp::ET_REL);
289 oehdr.put_e_machine(this->elf_machine_);
290 oehdr.put_e_version(elfcpp::EV_CURRENT);
291 oehdr.put_e_entry(0);
292 oehdr.put_e_phoff(0);
293 oehdr.put_e_shoff(elfcpp::Elf_sizes<size>::ehdr_size);
294 oehdr.put_e_flags(0);
295 oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
296 oehdr.put_e_phentsize(0);
297 oehdr.put_e_phnum(0);
298 oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
299 oehdr.put_e_shnum(5);
300 oehdr.put_e_shstrndx(4);
301
302 *ppout += elfcpp::Elf_sizes<size>::ehdr_size;
303}
304
305// Write out a section header.
306
307template<int size, bool big_endian>
308void
309Binary_to_elf::write_section_header(
310 const char* name,
311 const Stringpool* shstrtab,
312 elfcpp::SHT type,
313 unsigned int flags,
314 section_size_type offset,
315 section_size_type section_size,
316 unsigned int link,
317 unsigned int info,
318 unsigned int addralign,
319 unsigned int entsize,
320 unsigned char** ppout)
321{
322 elfcpp::Shdr_write<size, big_endian> oshdr(*ppout);
323
324 oshdr.put_sh_name(*name == '\0' ? 0 : shstrtab->get_offset(name));
325 oshdr.put_sh_type(type);
326 oshdr.put_sh_flags(flags);
327 oshdr.put_sh_addr(0);
328 oshdr.put_sh_offset(offset);
329 oshdr.put_sh_size(section_size);
330 oshdr.put_sh_link(link);
331 oshdr.put_sh_info(info);
332 oshdr.put_sh_addralign(addralign);
333 oshdr.put_sh_entsize(entsize);
334
335 *ppout += elfcpp::Elf_sizes<size>::shdr_size;
336}
337
338// Write out a symbol.
339
340template<int size, bool big_endian>
341void
342Binary_to_elf::write_symbol(
343 const std::string& name,
344 const Stringpool* strtab,
345 section_size_type value,
43b64deb 346 typename elfcpp::Elf_types<32>::Elf_WXword st_size,
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347 unsigned int shndx,
348 unsigned char** ppout)
349{
350 unsigned char* pout = *ppout;
351
352 elfcpp::Sym_write<size, big_endian> osym(pout);
353 osym.put_st_name(name.empty() ? 0 : strtab->get_offset(name.c_str()));
354 osym.put_st_value(value);
43b64deb 355 osym.put_st_size(st_size);
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356 osym.put_st_info(name.empty() ? elfcpp::STB_LOCAL : elfcpp::STB_GLOBAL,
357 elfcpp::STT_NOTYPE);
358 osym.put_st_other(elfcpp::STV_DEFAULT, 0);
359 osym.put_st_shndx(shndx);
360
361 *ppout += elfcpp::Elf_sizes<size>::sym_size;
362}
363
364} // End namespace gold.
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