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/Optional.h" 19 #include "llvm/ADT/STLExtras.h" 20 #include "llvm/ADT/SmallString.h" 21 #include "llvm/ADT/SmallVector.h" 22 #include "llvm/ADT/StringRef.h" 23 #include "llvm/ADT/Triple.h" 24 #include "llvm/Support/Allocator.h" 25 #include "llvm/Support/Casting.h" 26 #include "llvm/Support/CommandLine.h" 27 #include "llvm/Support/ErrorOr.h" 28 #include "llvm/Support/Host.h" 29 #include "llvm/Support/MemoryBuffer.h" 30 #include "llvm/Support/Path.h" 31 #include "llvm/Support/StringSaver.h" 32 #include "llvm/Support/VirtualFileSystem.h" 33 #include "llvm/Support/YAMLParser.h" 34 #include "llvm/Support/raw_ostream.h" 35 #include <cassert> 36 #include <memory> 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 Syntax = JSONCommandLineSyntax::Gnu; 139 llvm::Triple Triple(llvm::sys::getProcessTriple()); 140 if (Triple.getOS() == llvm::Triple::OSType::Win32) { 141 // Assume Windows command line parsing on Win32 unless the triple 142 // explicitly tells us otherwise. 143 if (!Triple.hasEnvironment() || 144 Triple.getEnvironment() == llvm::Triple::EnvironmentType::MSVC) 145 Syntax = JSONCommandLineSyntax::Windows; 146 } 147 } 148 149 if (Syntax == JSONCommandLineSyntax::Windows) { 150 llvm::BumpPtrAllocator Alloc; 151 llvm::StringSaver Saver(Alloc); 152 llvm::SmallVector<const char *, 64> T; 153 llvm::cl::TokenizeWindowsCommandLine(EscapedCommandLine, Saver, T); 154 std::vector<std::string> Result(T.begin(), T.end()); 155 return Result; 156 } 157 assert(Syntax == JSONCommandLineSyntax::Gnu); 158 CommandLineArgumentParser parser(EscapedCommandLine); 159 return parser.parse(); 160 } 161 162 // This plugin locates a nearby compile_command.json file, and also infers 163 // compile commands for files not present in the database. 164 class JSONCompilationDatabasePlugin : public CompilationDatabasePlugin { 165 std::unique_ptr<CompilationDatabase> 166 loadFromDirectory(StringRef Directory, std::string &ErrorMessage) override { 167 SmallString<1024> JSONDatabasePath(Directory); 168 llvm::sys::path::append(JSONDatabasePath, "compile_commands.json"); 169 auto Base = JSONCompilationDatabase::loadFromFile( 170 JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect); 171 return Base ? inferTargetAndDriverMode( 172 inferMissingCompileCommands(expandResponseFiles( 173 std::move(Base), llvm::vfs::getRealFileSystem()))) 174 : nullptr; 175 } 176 }; 177 178 } // namespace 179 180 // Register the JSONCompilationDatabasePlugin with the 181 // CompilationDatabasePluginRegistry using this statically initialized variable. 182 static CompilationDatabasePluginRegistry::Add<JSONCompilationDatabasePlugin> 183 X("json-compilation-database", "Reads JSON formatted compilation databases"); 184 185 namespace clang { 186 namespace tooling { 187 188 // This anchor is used to force the linker to link in the generated object file 189 // and thus register the JSONCompilationDatabasePlugin. 190 volatile int JSONAnchorSource = 0; 191 192 } // namespace tooling 193 } // namespace clang 194 195 std::unique_ptr<JSONCompilationDatabase> 196 JSONCompilationDatabase::loadFromFile(StringRef FilePath, 197 std::string &ErrorMessage, 198 JSONCommandLineSyntax Syntax) { 199 // Don't mmap: if we're a long-lived process, the build system may overwrite. 200 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> DatabaseBuffer = 201 llvm::MemoryBuffer::getFile(FilePath, /*IsText=*/false, 202 /*RequiresNullTerminator=*/true, 203 /*IsVolatile=*/true); 204 if (std::error_code Result = DatabaseBuffer.getError()) { 205 ErrorMessage = "Error while opening JSON database: " + Result.message(); 206 return nullptr; 207 } 208 std::unique_ptr<JSONCompilationDatabase> Database( 209 new JSONCompilationDatabase(std::move(*DatabaseBuffer), Syntax)); 210 if (!Database->parse(ErrorMessage)) 211 return nullptr; 212 return Database; 213 } 214 215 std::unique_ptr<JSONCompilationDatabase> 216 JSONCompilationDatabase::loadFromBuffer(StringRef DatabaseString, 217 std::string &ErrorMessage, 218 JSONCommandLineSyntax Syntax) { 219 std::unique_ptr<llvm::MemoryBuffer> DatabaseBuffer( 220 llvm::MemoryBuffer::getMemBufferCopy(DatabaseString)); 221 std::unique_ptr<JSONCompilationDatabase> Database( 222 new JSONCompilationDatabase(std::move(DatabaseBuffer), Syntax)); 223 if (!Database->parse(ErrorMessage)) 224 return nullptr; 225 return Database; 226 } 227 228 std::vector<CompileCommand> 229 JSONCompilationDatabase::getCompileCommands(StringRef FilePath) const { 230 SmallString<128> NativeFilePath; 231 llvm::sys::path::native(FilePath, NativeFilePath); 232 233 std::string Error; 234 llvm::raw_string_ostream ES(Error); 235 StringRef Match = MatchTrie.findEquivalent(NativeFilePath, ES); 236 if (Match.empty()) 237 return {}; 238 const auto CommandsRefI = IndexByFile.find(Match); 239 if (CommandsRefI == IndexByFile.end()) 240 return {}; 241 std::vector<CompileCommand> Commands; 242 getCommands(CommandsRefI->getValue(), Commands); 243 return Commands; 244 } 245 246 std::vector<std::string> 247 JSONCompilationDatabase::getAllFiles() const { 248 std::vector<std::string> Result; 249 for (const auto &CommandRef : IndexByFile) 250 Result.push_back(CommandRef.first().str()); 251 return Result; 252 } 253 254 std::vector<CompileCommand> 255 JSONCompilationDatabase::getAllCompileCommands() const { 256 std::vector<CompileCommand> Commands; 257 getCommands(AllCommands, Commands); 258 return Commands; 259 } 260 261 static llvm::StringRef stripExecutableExtension(llvm::StringRef Name) { 262 Name.consume_back(".exe"); 263 return Name; 264 } 265 266 // There are compiler-wrappers (ccache, distcc, gomacc) that take the "real" 267 // compiler as an argument, e.g. distcc gcc -O3 foo.c. 268 // These end up in compile_commands.json when people set CC="distcc gcc". 269 // Clang's driver doesn't understand this, so we need to unwrap. 270 static bool unwrapCommand(std::vector<std::string> &Args) { 271 if (Args.size() < 2) 272 return false; 273 StringRef Wrapper = 274 stripExecutableExtension(llvm::sys::path::filename(Args.front())); 275 if (Wrapper == "distcc" || Wrapper == "gomacc" || Wrapper == "ccache" || 276 Wrapper == "sccache") { 277 // Most of these wrappers support being invoked 3 ways: 278 // `distcc g++ file.c` This is the mode we're trying to match. 279 // We need to drop `distcc`. 280 // `distcc file.c` This acts like compiler is cc or similar. 281 // Clang's driver can handle this, no change needed. 282 // `g++ file.c` g++ is a symlink to distcc. 283 // We don't even notice this case, and all is well. 284 // 285 // We need to distinguish between the first and second case. 286 // The wrappers themselves don't take flags, so Args[1] is a compiler flag, 287 // an input file, or a compiler. Inputs have extensions, compilers don't. 288 bool HasCompiler = 289 (Args[1][0] != '-') && 290 !llvm::sys::path::has_extension(stripExecutableExtension(Args[1])); 291 if (HasCompiler) { 292 Args.erase(Args.begin()); 293 return true; 294 } 295 // If !HasCompiler, wrappers act like GCC. Fine: so do we. 296 } 297 return false; 298 } 299 300 static std::vector<std::string> 301 nodeToCommandLine(JSONCommandLineSyntax Syntax, 302 const std::vector<llvm::yaml::ScalarNode *> &Nodes) { 303 SmallString<1024> Storage; 304 std::vector<std::string> Arguments; 305 if (Nodes.size() == 1) 306 Arguments = unescapeCommandLine(Syntax, Nodes[0]->getValue(Storage)); 307 else 308 for (const auto *Node : Nodes) 309 Arguments.push_back(std::string(Node->getValue(Storage))); 310 // There may be multiple wrappers: using distcc and ccache together is common. 311 while (unwrapCommand(Arguments)) 312 ; 313 return Arguments; 314 } 315 316 void JSONCompilationDatabase::getCommands( 317 ArrayRef<CompileCommandRef> CommandsRef, 318 std::vector<CompileCommand> &Commands) const { 319 for (const auto &CommandRef : CommandsRef) { 320 SmallString<8> DirectoryStorage; 321 SmallString<32> FilenameStorage; 322 SmallString<32> OutputStorage; 323 auto Output = std::get<3>(CommandRef); 324 Commands.emplace_back( 325 std::get<0>(CommandRef)->getValue(DirectoryStorage), 326 std::get<1>(CommandRef)->getValue(FilenameStorage), 327 nodeToCommandLine(Syntax, std::get<2>(CommandRef)), 328 Output ? Output->getValue(OutputStorage) : ""); 329 } 330 } 331 332 bool JSONCompilationDatabase::parse(std::string &ErrorMessage) { 333 llvm::yaml::document_iterator I = YAMLStream.begin(); 334 if (I == YAMLStream.end()) { 335 ErrorMessage = "Error while parsing YAML."; 336 return false; 337 } 338 llvm::yaml::Node *Root = I->getRoot(); 339 if (!Root) { 340 ErrorMessage = "Error while parsing YAML."; 341 return false; 342 } 343 auto *Array = dyn_cast<llvm::yaml::SequenceNode>(Root); 344 if (!Array) { 345 ErrorMessage = "Expected array."; 346 return false; 347 } 348 for (auto &NextObject : *Array) { 349 auto *Object = dyn_cast<llvm::yaml::MappingNode>(&NextObject); 350 if (!Object) { 351 ErrorMessage = "Expected object."; 352 return false; 353 } 354 llvm::yaml::ScalarNode *Directory = nullptr; 355 llvm::Optional<std::vector<llvm::yaml::ScalarNode *>> Command; 356 llvm::yaml::ScalarNode *File = nullptr; 357 llvm::yaml::ScalarNode *Output = nullptr; 358 for (auto& NextKeyValue : *Object) { 359 auto *KeyString = dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey()); 360 if (!KeyString) { 361 ErrorMessage = "Expected strings as key."; 362 return false; 363 } 364 SmallString<10> KeyStorage; 365 StringRef KeyValue = KeyString->getValue(KeyStorage); 366 llvm::yaml::Node *Value = NextKeyValue.getValue(); 367 if (!Value) { 368 ErrorMessage = "Expected value."; 369 return false; 370 } 371 auto *ValueString = dyn_cast<llvm::yaml::ScalarNode>(Value); 372 auto *SequenceString = dyn_cast<llvm::yaml::SequenceNode>(Value); 373 if (KeyValue == "arguments") { 374 if (!SequenceString) { 375 ErrorMessage = "Expected sequence as value."; 376 return false; 377 } 378 Command = std::vector<llvm::yaml::ScalarNode *>(); 379 for (auto &Argument : *SequenceString) { 380 auto *Scalar = dyn_cast<llvm::yaml::ScalarNode>(&Argument); 381 if (!Scalar) { 382 ErrorMessage = "Only strings are allowed in 'arguments'."; 383 return false; 384 } 385 Command->push_back(Scalar); 386 } 387 } else { 388 if (!ValueString) { 389 ErrorMessage = "Expected string as value."; 390 return false; 391 } 392 if (KeyValue == "directory") { 393 Directory = ValueString; 394 } else if (KeyValue == "command") { 395 if (!Command) 396 Command = std::vector<llvm::yaml::ScalarNode *>(1, ValueString); 397 } else if (KeyValue == "file") { 398 File = ValueString; 399 } else if (KeyValue == "output") { 400 Output = ValueString; 401 } else { 402 ErrorMessage = 403 ("Unknown key: \"" + KeyString->getRawValue() + "\"").str(); 404 return false; 405 } 406 } 407 } 408 if (!File) { 409 ErrorMessage = "Missing key: \"file\"."; 410 return false; 411 } 412 if (!Command) { 413 ErrorMessage = "Missing key: \"command\" or \"arguments\"."; 414 return false; 415 } 416 if (!Directory) { 417 ErrorMessage = "Missing key: \"directory\"."; 418 return false; 419 } 420 SmallString<8> FileStorage; 421 StringRef FileName = File->getValue(FileStorage); 422 SmallString<128> NativeFilePath; 423 if (llvm::sys::path::is_relative(FileName)) { 424 SmallString<8> DirectoryStorage; 425 SmallString<128> AbsolutePath( 426 Directory->getValue(DirectoryStorage)); 427 llvm::sys::path::append(AbsolutePath, FileName); 428 llvm::sys::path::remove_dots(AbsolutePath, /*remove_dot_dot=*/ true); 429 llvm::sys::path::native(AbsolutePath, NativeFilePath); 430 } else { 431 llvm::sys::path::native(FileName, NativeFilePath); 432 } 433 auto Cmd = CompileCommandRef(Directory, File, *Command, Output); 434 IndexByFile[NativeFilePath].push_back(Cmd); 435 AllCommands.push_back(Cmd); 436 MatchTrie.insert(NativeFilePath); 437 } 438 return true; 439 } 440