1 /*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "elf_writer_quick.h"
18
19 #include <openssl/sha.h>
20 #include <unordered_map>
21 #include <unordered_set>
22
23 #include "base/casts.h"
24 #include "base/logging.h"
25 #include "base/stl_util.h"
26 #include "compiled_method.h"
27 #include "debug/elf_debug_writer.h"
28 #include "debug/method_debug_info.h"
29 #include "driver/compiler_options.h"
30 #include "elf.h"
31 #include "elf_builder.h"
32 #include "elf_utils.h"
33 #include "globals.h"
34 #include "leb128.h"
35 #include "linker/buffered_output_stream.h"
36 #include "linker/file_output_stream.h"
37 #include "thread-inl.h"
38 #include "thread_pool.h"
39 #include "utils.h"
40
41 namespace art {
42
43 // .eh_frame and .debug_frame are almost identical.
44 // Except for some minor formatting differences, the main difference
45 // is that .eh_frame is allocated within the running program because
46 // it is used by C++ exception handling (which we do not use so we
47 // can choose either). C++ compilers generally tend to use .eh_frame
48 // because if they need it sometimes, they might as well always use it.
49 // Let's use .debug_frame because it is easier to strip or compress.
50 constexpr dwarf::CFIFormat kCFIFormat = dwarf::DW_DEBUG_FRAME_FORMAT;
51
52 class DebugInfoTask : public Task {
53 public:
DebugInfoTask(InstructionSet isa,const InstructionSetFeatures * features,size_t rodata_section_size,size_t text_section_size,const ArrayRef<const debug::MethodDebugInfo> & method_infos)54 DebugInfoTask(InstructionSet isa,
55 const InstructionSetFeatures* features,
56 size_t rodata_section_size,
57 size_t text_section_size,
58 const ArrayRef<const debug::MethodDebugInfo>& method_infos)
59 : isa_(isa),
60 instruction_set_features_(features),
61 rodata_section_size_(rodata_section_size),
62 text_section_size_(text_section_size),
63 method_infos_(method_infos) {
64 }
65
Run(Thread *)66 void Run(Thread*) {
67 result_ = debug::MakeMiniDebugInfo(isa_,
68 instruction_set_features_,
69 rodata_section_size_,
70 text_section_size_,
71 method_infos_);
72 }
73
GetResult()74 std::vector<uint8_t>* GetResult() {
75 return &result_;
76 }
77
78 private:
79 InstructionSet isa_;
80 const InstructionSetFeatures* instruction_set_features_;
81 size_t rodata_section_size_;
82 size_t text_section_size_;
83 const ArrayRef<const debug::MethodDebugInfo>& method_infos_;
84 std::vector<uint8_t> result_;
85 };
86
87 template <typename ElfTypes>
88 class ElfWriterQuick FINAL : public ElfWriter {
89 public:
90 ElfWriterQuick(InstructionSet instruction_set,
91 const InstructionSetFeatures* features,
92 const CompilerOptions* compiler_options,
93 File* elf_file);
94 ~ElfWriterQuick();
95
96 void Start() OVERRIDE;
97 void PrepareDynamicSection(size_t rodata_size,
98 size_t text_size,
99 size_t bss_size,
100 size_t bss_roots_offset) OVERRIDE;
101 void PrepareDebugInfo(const ArrayRef<const debug::MethodDebugInfo>& method_infos) OVERRIDE;
102 OutputStream* StartRoData() OVERRIDE;
103 void EndRoData(OutputStream* rodata) OVERRIDE;
104 OutputStream* StartText() OVERRIDE;
105 void EndText(OutputStream* text) OVERRIDE;
106 void WriteDynamicSection() OVERRIDE;
107 void WriteDebugInfo(const ArrayRef<const debug::MethodDebugInfo>& method_infos) OVERRIDE;
108 bool End() OVERRIDE;
109
110 virtual OutputStream* GetStream() OVERRIDE;
111
112 size_t GetLoadedSize() OVERRIDE;
113
114 static void EncodeOatPatches(const std::vector<uintptr_t>& locations,
115 std::vector<uint8_t>* buffer);
116
117 private:
118 const InstructionSetFeatures* instruction_set_features_;
119 const CompilerOptions* const compiler_options_;
120 File* const elf_file_;
121 size_t rodata_size_;
122 size_t text_size_;
123 size_t bss_size_;
124 std::unique_ptr<BufferedOutputStream> output_stream_;
125 std::unique_ptr<ElfBuilder<ElfTypes>> builder_;
126 std::unique_ptr<DebugInfoTask> debug_info_task_;
127 std::unique_ptr<ThreadPool> debug_info_thread_pool_;
128
129 void ComputeFileBuildId(uint8_t (*build_id)[ElfBuilder<ElfTypes>::kBuildIdLen]);
130
131 DISALLOW_IMPLICIT_CONSTRUCTORS(ElfWriterQuick);
132 };
133
CreateElfWriterQuick(InstructionSet instruction_set,const InstructionSetFeatures * features,const CompilerOptions * compiler_options,File * elf_file)134 std::unique_ptr<ElfWriter> CreateElfWriterQuick(InstructionSet instruction_set,
135 const InstructionSetFeatures* features,
136 const CompilerOptions* compiler_options,
137 File* elf_file) {
138 if (Is64BitInstructionSet(instruction_set)) {
139 return MakeUnique<ElfWriterQuick<ElfTypes64>>(instruction_set,
140 features,
141 compiler_options,
142 elf_file);
143 } else {
144 return MakeUnique<ElfWriterQuick<ElfTypes32>>(instruction_set,
145 features,
146 compiler_options,
147 elf_file);
148 }
149 }
150
151 template <typename ElfTypes>
ElfWriterQuick(InstructionSet instruction_set,const InstructionSetFeatures * features,const CompilerOptions * compiler_options,File * elf_file)152 ElfWriterQuick<ElfTypes>::ElfWriterQuick(InstructionSet instruction_set,
153 const InstructionSetFeatures* features,
154 const CompilerOptions* compiler_options,
155 File* elf_file)
156 : ElfWriter(),
157 instruction_set_features_(features),
158 compiler_options_(compiler_options),
159 elf_file_(elf_file),
160 rodata_size_(0u),
161 text_size_(0u),
162 bss_size_(0u),
163 output_stream_(MakeUnique<BufferedOutputStream>(MakeUnique<FileOutputStream>(elf_file))),
164 builder_(new ElfBuilder<ElfTypes>(instruction_set, features, output_stream_.get())) {}
165
166 template <typename ElfTypes>
~ElfWriterQuick()167 ElfWriterQuick<ElfTypes>::~ElfWriterQuick() {}
168
169 template <typename ElfTypes>
Start()170 void ElfWriterQuick<ElfTypes>::Start() {
171 builder_->Start();
172 if (compiler_options_->GetGenerateBuildId()) {
173 builder_->WriteBuildIdSection();
174 }
175 }
176
177 template <typename ElfTypes>
PrepareDynamicSection(size_t rodata_size,size_t text_size,size_t bss_size,size_t bss_roots_offset)178 void ElfWriterQuick<ElfTypes>::PrepareDynamicSection(size_t rodata_size,
179 size_t text_size,
180 size_t bss_size,
181 size_t bss_roots_offset) {
182 DCHECK_EQ(rodata_size_, 0u);
183 rodata_size_ = rodata_size;
184 DCHECK_EQ(text_size_, 0u);
185 text_size_ = text_size;
186 DCHECK_EQ(bss_size_, 0u);
187 bss_size_ = bss_size;
188 builder_->PrepareDynamicSection(elf_file_->GetPath(),
189 rodata_size_,
190 text_size_,
191 bss_size_,
192 bss_roots_offset);
193 }
194
195 template <typename ElfTypes>
StartRoData()196 OutputStream* ElfWriterQuick<ElfTypes>::StartRoData() {
197 auto* rodata = builder_->GetRoData();
198 rodata->Start();
199 return rodata;
200 }
201
202 template <typename ElfTypes>
EndRoData(OutputStream * rodata)203 void ElfWriterQuick<ElfTypes>::EndRoData(OutputStream* rodata) {
204 CHECK_EQ(builder_->GetRoData(), rodata);
205 builder_->GetRoData()->End();
206 }
207
208 template <typename ElfTypes>
StartText()209 OutputStream* ElfWriterQuick<ElfTypes>::StartText() {
210 auto* text = builder_->GetText();
211 text->Start();
212 return text;
213 }
214
215 template <typename ElfTypes>
EndText(OutputStream * text)216 void ElfWriterQuick<ElfTypes>::EndText(OutputStream* text) {
217 CHECK_EQ(builder_->GetText(), text);
218 builder_->GetText()->End();
219 }
220
221 template <typename ElfTypes>
WriteDynamicSection()222 void ElfWriterQuick<ElfTypes>::WriteDynamicSection() {
223 if (bss_size_ != 0u) {
224 builder_->GetBss()->WriteNoBitsSection(bss_size_);
225 }
226 if (builder_->GetIsa() == kMips || builder_->GetIsa() == kMips64) {
227 builder_->WriteMIPSabiflagsSection();
228 }
229 builder_->WriteDynamicSection();
230 }
231
232 template <typename ElfTypes>
PrepareDebugInfo(const ArrayRef<const debug::MethodDebugInfo> & method_infos)233 void ElfWriterQuick<ElfTypes>::PrepareDebugInfo(
234 const ArrayRef<const debug::MethodDebugInfo>& method_infos) {
235 if (!method_infos.empty() && compiler_options_->GetGenerateMiniDebugInfo()) {
236 // Prepare the mini-debug-info in background while we do other I/O.
237 Thread* self = Thread::Current();
238 debug_info_task_ = std::unique_ptr<DebugInfoTask>(
239 new DebugInfoTask(builder_->GetIsa(),
240 instruction_set_features_,
241 rodata_size_,
242 text_size_,
243 method_infos));
244 debug_info_thread_pool_ = std::unique_ptr<ThreadPool>(
245 new ThreadPool("Mini-debug-info writer", 1));
246 debug_info_thread_pool_->AddTask(self, debug_info_task_.get());
247 debug_info_thread_pool_->StartWorkers(self);
248 }
249 }
250
251 template <typename ElfTypes>
WriteDebugInfo(const ArrayRef<const debug::MethodDebugInfo> & method_infos)252 void ElfWriterQuick<ElfTypes>::WriteDebugInfo(
253 const ArrayRef<const debug::MethodDebugInfo>& method_infos) {
254 if (!method_infos.empty()) {
255 if (compiler_options_->GetGenerateDebugInfo()) {
256 // Generate all the debug information we can.
257 debug::WriteDebugInfo(builder_.get(), method_infos, kCFIFormat, true /* write_oat_patches */);
258 }
259 if (compiler_options_->GetGenerateMiniDebugInfo()) {
260 // Wait for the mini-debug-info generation to finish and write it to disk.
261 Thread* self = Thread::Current();
262 DCHECK(debug_info_thread_pool_ != nullptr);
263 debug_info_thread_pool_->Wait(self, true, false);
264 builder_->WriteSection(".gnu_debugdata", debug_info_task_->GetResult());
265 }
266 }
267 }
268
269 template <typename ElfTypes>
End()270 bool ElfWriterQuick<ElfTypes>::End() {
271 builder_->End();
272 if (compiler_options_->GetGenerateBuildId()) {
273 uint8_t build_id[ElfBuilder<ElfTypes>::kBuildIdLen];
274 ComputeFileBuildId(&build_id);
275 builder_->WriteBuildId(build_id);
276 }
277 return builder_->Good();
278 }
279
280 template <typename ElfTypes>
ComputeFileBuildId(uint8_t (* build_id)[ElfBuilder<ElfTypes>::kBuildIdLen])281 void ElfWriterQuick<ElfTypes>::ComputeFileBuildId(
282 uint8_t (*build_id)[ElfBuilder<ElfTypes>::kBuildIdLen]) {
283 constexpr int kBufSize = 8192;
284 std::vector<char> buffer(kBufSize);
285 int64_t offset = 0;
286 SHA_CTX ctx;
287 SHA1_Init(&ctx);
288 while (true) {
289 int64_t bytes_read = elf_file_->Read(buffer.data(), kBufSize, offset);
290 CHECK_GE(bytes_read, 0);
291 if (bytes_read == 0) {
292 // End of file.
293 break;
294 }
295 SHA1_Update(&ctx, buffer.data(), bytes_read);
296 offset += bytes_read;
297 }
298 SHA1_Final(*build_id, &ctx);
299 }
300
301 template <typename ElfTypes>
GetStream()302 OutputStream* ElfWriterQuick<ElfTypes>::GetStream() {
303 return builder_->GetStream();
304 }
305
306 template <typename ElfTypes>
GetLoadedSize()307 size_t ElfWriterQuick<ElfTypes>::GetLoadedSize() {
308 return builder_->GetLoadedSize();
309 }
310
311 // Explicit instantiations
312 template class ElfWriterQuick<ElfTypes32>;
313 template class ElfWriterQuick<ElfTypes64>;
314
315 } // namespace art
316