gdb: add target_ops::supports_displaced_step
[deliverable/binutils-gdb.git] / gold / binary.cc
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1// binary.cc -- binary input files for gold
2
b3adc24a 3// Copyright (C) 2008-2020 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>
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27
28#include "elfcpp.h"
29#include "stringpool.h"
30#include "fileread.h"
31#include "output.h"
32#include "binary.h"
33
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34// safe-ctype.h interferes with macros defined by the system <ctype.h>.
35// Some C++ system headers might include <ctype.h> and rely on its macro
36// definitions being intact. So make sure that safe-ctype.h is included
37// only after any C++ system headers, whether directly here (above) or via
38// other local header files (e.g. #include <string> in "binary.h").
39#include "safe-ctype.h"
40
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41// Support for reading binary files as input. These become blobs in
42// the final output. These files are treated as though they have a
43// single .data section and define three symbols:
602b464e 44// _binary_FILENAME_start, _binary_FILENAME_end, _binary_FILENAME_size.
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45// The FILENAME is the name of the input file, with any
46// non-alphanumeric character changed to an underscore.
47
48// We implement this by creating an ELF file in memory.
49
50namespace gold
51{
52
53// class Binary_to_elf.
54
55Binary_to_elf::Binary_to_elf(elfcpp::EM machine, int size, bool big_endian,
56 const std::string& filename)
57 : elf_machine_(machine), size_(size), big_endian_(big_endian),
58 filename_(filename), data_(NULL), filesize_(0)
59{
60}
61
62Binary_to_elf::~Binary_to_elf()
63{
64 if (this->data_ != NULL)
65 delete[] this->data_;
66}
67
68// Given FILENAME, create a buffer which looks like an ELF file with
69// the contents of FILENAME as the contents of the only section. The
70// TASK parameters is mainly for debugging, and records who holds
71// locks.
72
73bool
74Binary_to_elf::convert(const Task* task)
75{
76 if (this->size_ == 32)
77 {
78 if (!this->big_endian_)
79 {
80#ifdef HAVE_TARGET_32_LITTLE
81 return this->sized_convert<32, false>(task);
82#else
83 gold_unreachable();
84#endif
85 }
86 else
87 {
88#ifdef HAVE_TARGET_32_BIG
89 return this->sized_convert<32, true>(task);
90#else
91 gold_unreachable();
92#endif
93 }
94 }
95 else if (this->size_ == 64)
96 {
97 if (!this->big_endian_)
98 {
99#ifdef HAVE_TARGET_64_LITTLE
100 return this->sized_convert<64, false>(task);
101#else
102 gold_unreachable();
103#endif
104 }
105 else
106 {
107#ifdef HAVE_TARGET_64_BIG
108 return this->sized_convert<64, true>(task);
109#else
110 gold_unreachable();
111#endif
112 }
113 }
114 else
115 gold_unreachable();
116}
117
118// We are going to create:
119// * The ELF file header.
120// * Five sections: null section, .data, .symtab, .strtab, .shstrtab
121// * The contents of the file.
122// * Four symbols: null, begin, end, size.
123// * Three symbol names.
124// * Four section names.
125
126template<int size, bool big_endian>
127bool
128Binary_to_elf::sized_convert(const Task* task)
129{
130 // Read the input file.
131
132 File_read f;
133 if (!f.open(task, this->filename_))
134 {
135 gold_error(_("cannot open %s: %s:"), this->filename_.c_str(),
136 strerror(errno));
137 return false;
138 }
139
140 section_size_type filesize = convert_to_section_size_type(f.filesize());
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141 const unsigned char* fileview;
142 if (filesize == 0)
143 fileview = NULL;
144 else
145 fileview = f.get_view(0, 0, filesize, false, false);
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146
147 unsigned int align;
148 if (size == 32)
149 align = 4;
150 else if (size == 64)
151 align = 8;
152 else
153 gold_unreachable();
154 section_size_type aligned_filesize = align_address(filesize, align);
155
156 // Build the stringpool for the symbol table.
157
158 std::string mangled_name = this->filename_;
159 for (std::string::iterator p = mangled_name.begin();
160 p != mangled_name.end();
161 ++p)
162 if (!ISALNUM(*p))
163 *p = '_';
164 mangled_name = "_binary_" + mangled_name;
165 std::string start_symbol_name = mangled_name + "_start";
166 std::string end_symbol_name = mangled_name + "_end";
167 std::string size_symbol_name = mangled_name + "_size";
168
169 Stringpool strtab;
170 strtab.add(start_symbol_name.c_str(), false, NULL);
171 strtab.add(end_symbol_name.c_str(), false, NULL);
172 strtab.add(size_symbol_name.c_str(), false, NULL);
173 strtab.set_string_offsets();
174
175 // Build the stringpool for the section name table.
176
177 Stringpool shstrtab;
178 shstrtab.add(".data", false, NULL);
179 shstrtab.add(".symtab", false, NULL);
180 shstrtab.add(".strtab", false, NULL);
181 shstrtab.add(".shstrtab", false, NULL);
182 shstrtab.set_string_offsets();
183
184 // Work out the size of the generated file, and the offsets of the
185 // various sections, and allocate a buffer.
186
187 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
188
189 size_t output_size = (elfcpp::Elf_sizes<size>::ehdr_size
190 + 5 * elfcpp::Elf_sizes<size>::shdr_size);
191 size_t data_offset = output_size;
192 output_size += aligned_filesize;
193 size_t symtab_offset = output_size;
194 output_size += 4 * sym_size;
195 size_t strtab_offset = output_size;
196 output_size += strtab.get_strtab_size();
197 size_t shstrtab_offset = output_size;
198 output_size += shstrtab.get_strtab_size();
199
200 unsigned char* buffer = new unsigned char[output_size];
201
202 // Write out the data.
203
204 unsigned char* pout = buffer;
205
206 this->write_file_header<size, big_endian>(&pout);
207
208 this->write_section_header<size, big_endian>("", &shstrtab, elfcpp::SHT_NULL,
209 0, 0, 0, 0, 0,
210 0, 0, &pout);
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211 // Having the section be named ".data", having it be writable, and
212 // giving it an alignment of 1 is because the GNU linker does it
213 // that way, and existing linker script expect it.
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214 this->write_section_header<size, big_endian>(".data", &shstrtab,
215 elfcpp::SHT_PROGBITS,
216 (elfcpp::SHF_ALLOC
217 | elfcpp::SHF_WRITE),
218 data_offset,
219 filesize, 0, 0,
f0b886e3 220 1, 0, &pout);
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221 this->write_section_header<size, big_endian>(".symtab", &shstrtab,
222 elfcpp::SHT_SYMTAB,
223 0, symtab_offset, 4 * sym_size,
224 3, 1, align, sym_size, &pout);
225 this->write_section_header<size, big_endian>(".strtab", &shstrtab,
226 elfcpp::SHT_STRTAB,
227 0, strtab_offset,
228 strtab.get_strtab_size(),
229 0, 0, 1, 0, &pout);
230 this->write_section_header<size, big_endian>(".shstrtab", &shstrtab,
231 elfcpp::SHT_STRTAB,
232 0, shstrtab_offset,
233 shstrtab.get_strtab_size(),
234 0, 0, 1, 0, &pout);
235
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236 if (filesize > 0)
237 {
238 memcpy(pout, fileview, filesize);
239 pout += filesize;
240 memset(pout, 0, aligned_filesize - filesize);
241 pout += aligned_filesize - filesize;
242 }
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244 this->write_symbol<size, big_endian>("", &strtab, 0, 0, 0, &pout);
245 this->write_symbol<size, big_endian>(start_symbol_name, &strtab, 0, filesize,
246 1, &pout);
247 this->write_symbol<size, big_endian>(end_symbol_name, &strtab, filesize, 0,
248 1, &pout);
249 this->write_symbol<size, big_endian>(size_symbol_name, &strtab, filesize, 0,
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250 elfcpp::SHN_ABS, &pout);
251
252 strtab.write_to_buffer(pout, strtab.get_strtab_size());
253 pout += strtab.get_strtab_size();
254
255 shstrtab.write_to_buffer(pout, shstrtab.get_strtab_size());
256 pout += shstrtab.get_strtab_size();
257
258 gold_assert(static_cast<size_t>(pout - buffer) == output_size);
259
260 this->data_ = buffer;
261 this->filesize_ = output_size;
262
263 f.unlock(task);
264
265 return true;
266}
267
268// Write out the file header.
269
270template<int size, bool big_endian>
271void
272Binary_to_elf::write_file_header(unsigned char** ppout)
273{
274 elfcpp::Ehdr_write<size, big_endian> oehdr(*ppout);
275
276 unsigned char e_ident[elfcpp::EI_NIDENT];
277 memset(e_ident, 0, elfcpp::EI_NIDENT);
278 e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;
279 e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;
280 e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;
281 e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;
282 if (size == 32)
283 e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;
284 else if (size == 64)
285 e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;
286 else
287 gold_unreachable();
288 e_ident[elfcpp::EI_DATA] = (big_endian
289 ? elfcpp::ELFDATA2MSB
290 : elfcpp::ELFDATA2LSB);
291 e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
292 oehdr.put_e_ident(e_ident);
293
294 oehdr.put_e_type(elfcpp::ET_REL);
295 oehdr.put_e_machine(this->elf_machine_);
296 oehdr.put_e_version(elfcpp::EV_CURRENT);
297 oehdr.put_e_entry(0);
298 oehdr.put_e_phoff(0);
299 oehdr.put_e_shoff(elfcpp::Elf_sizes<size>::ehdr_size);
300 oehdr.put_e_flags(0);
301 oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
302 oehdr.put_e_phentsize(0);
303 oehdr.put_e_phnum(0);
304 oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
305 oehdr.put_e_shnum(5);
306 oehdr.put_e_shstrndx(4);
307
308 *ppout += elfcpp::Elf_sizes<size>::ehdr_size;
309}
310
311// Write out a section header.
312
313template<int size, bool big_endian>
314void
315Binary_to_elf::write_section_header(
316 const char* name,
317 const Stringpool* shstrtab,
318 elfcpp::SHT type,
319 unsigned int flags,
320 section_size_type offset,
321 section_size_type section_size,
322 unsigned int link,
323 unsigned int info,
324 unsigned int addralign,
325 unsigned int entsize,
326 unsigned char** ppout)
327{
328 elfcpp::Shdr_write<size, big_endian> oshdr(*ppout);
329
330 oshdr.put_sh_name(*name == '\0' ? 0 : shstrtab->get_offset(name));
331 oshdr.put_sh_type(type);
332 oshdr.put_sh_flags(flags);
333 oshdr.put_sh_addr(0);
334 oshdr.put_sh_offset(offset);
335 oshdr.put_sh_size(section_size);
336 oshdr.put_sh_link(link);
337 oshdr.put_sh_info(info);
338 oshdr.put_sh_addralign(addralign);
339 oshdr.put_sh_entsize(entsize);
340
341 *ppout += elfcpp::Elf_sizes<size>::shdr_size;
342}
343
344// Write out a symbol.
345
346template<int size, bool big_endian>
347void
348Binary_to_elf::write_symbol(
349 const std::string& name,
350 const Stringpool* strtab,
351 section_size_type value,
43b64deb 352 typename elfcpp::Elf_types<32>::Elf_WXword st_size,
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353 unsigned int shndx,
354 unsigned char** ppout)
355{
356 unsigned char* pout = *ppout;
357
358 elfcpp::Sym_write<size, big_endian> osym(pout);
359 osym.put_st_name(name.empty() ? 0 : strtab->get_offset(name.c_str()));
360 osym.put_st_value(value);
43b64deb 361 osym.put_st_size(st_size);
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362 osym.put_st_info(name.empty() ? elfcpp::STB_LOCAL : elfcpp::STB_GLOBAL,
363 elfcpp::STT_NOTYPE);
364 osym.put_st_other(elfcpp::STV_DEFAULT, 0);
365 osym.put_st_shndx(shndx);
366
367 *ppout += elfcpp::Elf_sizes<size>::sym_size;
368}
369
370} // End namespace gold.
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