1 //===- JSONCompilationDatabase.cpp ----------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains the implementation of the JSONCompilationDatabase. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "clang/Tooling/JSONCompilationDatabase.h" 14 #include "clang/Basic/LLVM.h" 15 #include "clang/Tooling/CompilationDatabase.h" 16 #include "clang/Tooling/CompilationDatabasePluginRegistry.h" 17 #include "clang/Tooling/Tooling.h" 18 #include "llvm/ADT/STLExtras.h" 19 #include "llvm/ADT/SmallString.h" 20 #include "llvm/ADT/SmallVector.h" 21 #include "llvm/ADT/StringRef.h" 22 #include "llvm/Support/Allocator.h" 23 #include "llvm/Support/Casting.h" 24 #include "llvm/Support/CommandLine.h" 25 #include "llvm/Support/ErrorOr.h" 26 #include "llvm/Support/MemoryBuffer.h" 27 #include "llvm/Support/Path.h" 28 #include "llvm/Support/StringSaver.h" 29 #include "llvm/Support/VirtualFileSystem.h" 30 #include "llvm/Support/YAMLParser.h" 31 #include "llvm/Support/raw_ostream.h" 32 #include "llvm/TargetParser/Host.h" 33 #include "llvm/TargetParser/Triple.h" 34 #include <cassert> 35 #include <memory> 36 #include <optional> 37 #include <string> 38 #include <system_error> 39 #include <tuple> 40 #include <utility> 41 #include <vector> 42 43 using namespace clang; 44 using namespace tooling; 45 46 namespace { 47 48 /// A parser for escaped strings of command line arguments. 49 /// 50 /// Assumes \-escaping for quoted arguments (see the documentation of 51 /// unescapeCommandLine(...)). 52 class CommandLineArgumentParser { 53 public: 54 CommandLineArgumentParser(StringRef CommandLine) 55 : Input(CommandLine), Position(Input.begin()-1) {} 56 57 std::vector<std::string> parse() { 58 bool HasMoreInput = true; 59 while (HasMoreInput && nextNonWhitespace()) { 60 std::string Argument; 61 HasMoreInput = parseStringInto(Argument); 62 CommandLine.push_back(Argument); 63 } 64 return CommandLine; 65 } 66 67 private: 68 // All private methods return true if there is more input available. 69 70 bool parseStringInto(std::string &String) { 71 do { 72 if (*Position == '"') { 73 if (!parseDoubleQuotedStringInto(String)) return false; 74 } else if (*Position == '\'') { 75 if (!parseSingleQuotedStringInto(String)) return false; 76 } else { 77 if (!parseFreeStringInto(String)) return false; 78 } 79 } while (*Position != ' '); 80 return true; 81 } 82 83 bool parseDoubleQuotedStringInto(std::string &String) { 84 if (!next()) return false; 85 while (*Position != '"') { 86 if (!skipEscapeCharacter()) return false; 87 String.push_back(*Position); 88 if (!next()) return false; 89 } 90 return next(); 91 } 92 93 bool parseSingleQuotedStringInto(std::string &String) { 94 if (!next()) return false; 95 while (*Position != '\'') { 96 String.push_back(*Position); 97 if (!next()) return false; 98 } 99 return next(); 100 } 101 102 bool parseFreeStringInto(std::string &String) { 103 do { 104 if (!skipEscapeCharacter()) return false; 105 String.push_back(*Position); 106 if (!next()) return false; 107 } while (*Position != ' ' && *Position != '"' && *Position != '\''); 108 return true; 109 } 110 111 bool skipEscapeCharacter() { 112 if (*Position == '\\') { 113 return next(); 114 } 115 return true; 116 } 117 118 bool nextNonWhitespace() { 119 do { 120 if (!next()) return false; 121 } while (*Position == ' '); 122 return true; 123 } 124 125 bool next() { 126 ++Position; 127 return Position != Input.end(); 128 } 129 130 const StringRef Input; 131 StringRef::iterator Position; 132 std::vector<std::string> CommandLine; 133 }; 134 135 std::vector<std::string> unescapeCommandLine(JSONCommandLineSyntax Syntax, 136 StringRef EscapedCommandLine) { 137 if (Syntax == JSONCommandLineSyntax::AutoDetect) { 138 #ifdef _WIN32 139 // Assume Windows command line parsing on Win32 140 Syntax = JSONCommandLineSyntax::Windows; 141 #else 142 Syntax = JSONCommandLineSyntax::Gnu; 143 #endif 144 } 145 146 if (Syntax == JSONCommandLineSyntax::Windows) { 147 llvm::BumpPtrAllocator Alloc; 148 llvm::StringSaver Saver(Alloc); 149 llvm::SmallVector<const char *, 64> T; 150 llvm::cl::TokenizeWindowsCommandLine(EscapedCommandLine, Saver, T); 151 std::vector<std::string> Result(T.begin(), T.end()); 152 return Result; 153 } 154 assert(Syntax == JSONCommandLineSyntax::Gnu); 155 CommandLineArgumentParser parser(EscapedCommandLine); 156 return parser.parse(); 157 } 158 159 // This plugin locates a nearby compile_command.json file, and also infers 160 // compile commands for files not present in the database. 161 class JSONCompilationDatabasePlugin : public CompilationDatabasePlugin { 162 std::unique_ptr<CompilationDatabase> 163 loadFromDirectory(StringRef Directory, std::string &ErrorMessage) override { 164 SmallString<1024> JSONDatabasePath(Directory); 165 llvm::sys::path::append(JSONDatabasePath, "compile_commands.json"); 166 auto Base = JSONCompilationDatabase::loadFromFile( 167 JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect); 168 return Base ? inferTargetAndDriverMode( 169 inferMissingCompileCommands(expandResponseFiles( 170 std::move(Base), llvm::vfs::getRealFileSystem()))) 171 : nullptr; 172 } 173 }; 174 175 } // namespace 176 177 // Register the JSONCompilationDatabasePlugin with the 178 // CompilationDatabasePluginRegistry using this statically initialized variable. 179 static CompilationDatabasePluginRegistry::Add<JSONCompilationDatabasePlugin> 180 X("json-compilation-database", "Reads JSON formatted compilation databases"); 181 182 namespace clang { 183 namespace tooling { 184 185 // This anchor is used to force the linker to link in the generated object file 186 // and thus register the JSONCompilationDatabasePlugin. 187 volatile int JSONAnchorSource = 0; 188 189 } // namespace tooling 190 } // namespace clang 191 192 std::unique_ptr<JSONCompilationDatabase> 193 JSONCompilationDatabase::loadFromFile(StringRef FilePath, 194 std::string &ErrorMessage, 195 JSONCommandLineSyntax Syntax) { 196 // Don't mmap: if we're a long-lived process, the build system may overwrite. 197 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> DatabaseBuffer = 198 llvm::MemoryBuffer::getFile(FilePath, /*IsText=*/false, 199 /*RequiresNullTerminator=*/true, 200 /*IsVolatile=*/true); 201 if (std::error_code Result = DatabaseBuffer.getError()) { 202 ErrorMessage = "Error while opening JSON database: " + Result.message(); 203 return nullptr; 204 } 205 std::unique_ptr<JSONCompilationDatabase> Database( 206 new JSONCompilationDatabase(std::move(*DatabaseBuffer), Syntax)); 207 if (!Database->parse(ErrorMessage)) 208 return nullptr; 209 return Database; 210 } 211 212 std::unique_ptr<JSONCompilationDatabase> 213 JSONCompilationDatabase::loadFromBuffer(StringRef DatabaseString, 214 std::string &ErrorMessage, 215 JSONCommandLineSyntax Syntax) { 216 std::unique_ptr<llvm::MemoryBuffer> DatabaseBuffer( 217 llvm::MemoryBuffer::getMemBufferCopy(DatabaseString)); 218 std::unique_ptr<JSONCompilationDatabase> Database( 219 new JSONCompilationDatabase(std::move(DatabaseBuffer), Syntax)); 220 if (!Database->parse(ErrorMessage)) 221 return nullptr; 222 return Database; 223 } 224 225 std::vector<CompileCommand> 226 JSONCompilationDatabase::getCompileCommands(StringRef FilePath) const { 227 SmallString<128> NativeFilePath; 228 llvm::sys::path::native(FilePath, NativeFilePath); 229 230 std::string Error; 231 llvm::raw_string_ostream ES(Error); 232 StringRef Match = MatchTrie.findEquivalent(NativeFilePath, ES); 233 if (Match.empty()) 234 return {}; 235 const auto CommandsRefI = IndexByFile.find(Match); 236 if (CommandsRefI == IndexByFile.end()) 237 return {}; 238 std::vector<CompileCommand> Commands; 239 getCommands(CommandsRefI->getValue(), Commands); 240 return Commands; 241 } 242 243 std::vector<std::string> 244 JSONCompilationDatabase::getAllFiles() const { 245 std::vector<std::string> Result; 246 for (const auto &CommandRef : IndexByFile) 247 Result.push_back(CommandRef.first().str()); 248 return Result; 249 } 250 251 std::vector<CompileCommand> 252 JSONCompilationDatabase::getAllCompileCommands() const { 253 std::vector<CompileCommand> Commands; 254 getCommands(AllCommands, Commands); 255 return Commands; 256 } 257 258 static llvm::StringRef stripExecutableExtension(llvm::StringRef Name) { 259 Name.consume_back(".exe"); 260 return Name; 261 } 262 263 // There are compiler-wrappers (ccache, distcc, gomacc) that take the "real" 264 // compiler as an argument, e.g. distcc gcc -O3 foo.c. 265 // These end up in compile_commands.json when people set CC="distcc gcc". 266 // Clang's driver doesn't understand this, so we need to unwrap. 267 static bool unwrapCommand(std::vector<std::string> &Args) { 268 if (Args.size() < 2) 269 return false; 270 StringRef Wrapper = 271 stripExecutableExtension(llvm::sys::path::filename(Args.front())); 272 if (Wrapper == "distcc" || Wrapper == "gomacc" || Wrapper == "ccache" || 273 Wrapper == "sccache") { 274 // Most of these wrappers support being invoked 3 ways: 275 // `distcc g++ file.c` This is the mode we're trying to match. 276 // We need to drop `distcc`. 277 // `distcc file.c` This acts like compiler is cc or similar. 278 // Clang's driver can handle this, no change needed. 279 // `g++ file.c` g++ is a symlink to distcc. 280 // We don't even notice this case, and all is well. 281 // 282 // We need to distinguish between the first and second case. 283 // The wrappers themselves don't take flags, so Args[1] is a compiler flag, 284 // an input file, or a compiler. Inputs have extensions, compilers don't. 285 bool HasCompiler = 286 (Args[1][0] != '-') && 287 !llvm::sys::path::has_extension(stripExecutableExtension(Args[1])); 288 if (HasCompiler) { 289 Args.erase(Args.begin()); 290 return true; 291 } 292 // If !HasCompiler, wrappers act like GCC. Fine: so do we. 293 } 294 return false; 295 } 296 297 static std::vector<std::string> 298 nodeToCommandLine(JSONCommandLineSyntax Syntax, 299 const std::vector<llvm::yaml::ScalarNode *> &Nodes) { 300 SmallString<1024> Storage; 301 std::vector<std::string> Arguments; 302 if (Nodes.size() == 1) 303 Arguments = unescapeCommandLine(Syntax, Nodes[0]->getValue(Storage)); 304 else 305 for (const auto *Node : Nodes) 306 Arguments.push_back(std::string(Node->getValue(Storage))); 307 // There may be multiple wrappers: using distcc and ccache together is common. 308 while (unwrapCommand(Arguments)) 309 ; 310 return Arguments; 311 } 312 313 void JSONCompilationDatabase::getCommands( 314 ArrayRef<CompileCommandRef> CommandsRef, 315 std::vector<CompileCommand> &Commands) const { 316 for (const auto &CommandRef : CommandsRef) { 317 SmallString<8> DirectoryStorage; 318 SmallString<32> FilenameStorage; 319 SmallString<32> OutputStorage; 320 auto Output = std::get<3>(CommandRef); 321 Commands.emplace_back( 322 std::get<0>(CommandRef)->getValue(DirectoryStorage), 323 std::get<1>(CommandRef)->getValue(FilenameStorage), 324 nodeToCommandLine(Syntax, std::get<2>(CommandRef)), 325 Output ? Output->getValue(OutputStorage) : ""); 326 } 327 } 328 329 bool JSONCompilationDatabase::parse(std::string &ErrorMessage) { 330 llvm::yaml::document_iterator I = YAMLStream.begin(); 331 if (I == YAMLStream.end()) { 332 ErrorMessage = "Error while parsing YAML."; 333 return false; 334 } 335 llvm::yaml::Node *Root = I->getRoot(); 336 if (!Root) { 337 ErrorMessage = "Error while parsing YAML."; 338 return false; 339 } 340 auto *Array = dyn_cast<llvm::yaml::SequenceNode>(Root); 341 if (!Array) { 342 ErrorMessage = "Expected array."; 343 return false; 344 } 345 for (auto &NextObject : *Array) { 346 auto *Object = dyn_cast<llvm::yaml::MappingNode>(&NextObject); 347 if (!Object) { 348 ErrorMessage = "Expected object."; 349 return false; 350 } 351 llvm::yaml::ScalarNode *Directory = nullptr; 352 std::optional<std::vector<llvm::yaml::ScalarNode *>> Command; 353 llvm::yaml::ScalarNode *File = nullptr; 354 llvm::yaml::ScalarNode *Output = nullptr; 355 for (auto& NextKeyValue : *Object) { 356 auto *KeyString = dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey()); 357 if (!KeyString) { 358 ErrorMessage = "Expected strings as key."; 359 return false; 360 } 361 SmallString<10> KeyStorage; 362 StringRef KeyValue = KeyString->getValue(KeyStorage); 363 llvm::yaml::Node *Value = NextKeyValue.getValue(); 364 if (!Value) { 365 ErrorMessage = "Expected value."; 366 return false; 367 } 368 auto *ValueString = dyn_cast<llvm::yaml::ScalarNode>(Value); 369 auto *SequenceString = dyn_cast<llvm::yaml::SequenceNode>(Value); 370 if (KeyValue == "arguments") { 371 if (!SequenceString) { 372 ErrorMessage = "Expected sequence as value."; 373 return false; 374 } 375 Command = std::vector<llvm::yaml::ScalarNode *>(); 376 for (auto &Argument : *SequenceString) { 377 auto *Scalar = dyn_cast<llvm::yaml::ScalarNode>(&Argument); 378 if (!Scalar) { 379 ErrorMessage = "Only strings are allowed in 'arguments'."; 380 return false; 381 } 382 Command->push_back(Scalar); 383 } 384 } else { 385 if (!ValueString) { 386 ErrorMessage = "Expected string as value."; 387 return false; 388 } 389 if (KeyValue == "directory") { 390 Directory = ValueString; 391 } else if (KeyValue == "command") { 392 if (!Command) 393 Command = std::vector<llvm::yaml::ScalarNode *>(1, ValueString); 394 } else if (KeyValue == "file") { 395 File = ValueString; 396 } else if (KeyValue == "output") { 397 Output = ValueString; 398 } else { 399 ErrorMessage = 400 ("Unknown key: \"" + KeyString->getRawValue() + "\"").str(); 401 return false; 402 } 403 } 404 } 405 if (!File) { 406 ErrorMessage = "Missing key: \"file\"."; 407 return false; 408 } 409 if (!Command) { 410 ErrorMessage = "Missing key: \"command\" or \"arguments\"."; 411 return false; 412 } 413 if (!Directory) { 414 ErrorMessage = "Missing key: \"directory\"."; 415 return false; 416 } 417 SmallString<8> FileStorage; 418 StringRef FileName = File->getValue(FileStorage); 419 SmallString<128> NativeFilePath; 420 if (llvm::sys::path::is_relative(FileName)) { 421 SmallString<8> DirectoryStorage; 422 SmallString<128> AbsolutePath(Directory->getValue(DirectoryStorage)); 423 llvm::sys::path::append(AbsolutePath, FileName); 424 llvm::sys::path::native(AbsolutePath, NativeFilePath); 425 } else { 426 llvm::sys::path::native(FileName, NativeFilePath); 427 } 428 llvm::sys::path::remove_dots(NativeFilePath, /*remove_dot_dot=*/true); 429 auto Cmd = CompileCommandRef(Directory, File, *Command, Output); 430 IndexByFile[NativeFilePath].push_back(Cmd); 431 AllCommands.push_back(Cmd); 432 MatchTrie.insert(NativeFilePath); 433 } 434 return true; 435 } 436