430 lines · cpp
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-exception6//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/SmallVector.h"19#include "llvm/ADT/StringRef.h"20#include "llvm/Support/Allocator.h"21#include "llvm/Support/CommandLine.h"22#include "llvm/Support/ErrorOr.h"23#include "llvm/Support/MemoryBuffer.h"24#include "llvm/Support/Path.h"25#include "llvm/Support/StringSaver.h"26#include "llvm/Support/VirtualFileSystem.h"27#include "llvm/Support/YAMLParser.h"28#include "llvm/Support/raw_ostream.h"29#include "llvm/TargetParser/Host.h"30#include <cassert>31#include <memory>32#include <optional>33#include <string>34#include <system_error>35#include <utility>36#include <vector>37 38using namespace clang;39using namespace tooling;40 41namespace {42 43/// A parser for escaped strings of command line arguments.44///45/// Assumes \-escaping for quoted arguments (see the documentation of46/// unescapeCommandLine(...)).47class CommandLineArgumentParser {48 public:49 CommandLineArgumentParser(StringRef CommandLine)50 : Input(CommandLine), Position(Input.begin()-1) {}51 52 std::vector<std::string> parse() {53 bool HasMoreInput = true;54 while (HasMoreInput && nextNonWhitespace()) {55 std::string Argument;56 HasMoreInput = parseStringInto(Argument);57 CommandLine.push_back(Argument);58 }59 return CommandLine;60 }61 62 private:63 // All private methods return true if there is more input available.64 65 bool parseStringInto(std::string &String) {66 do {67 if (*Position == '"') {68 if (!parseDoubleQuotedStringInto(String)) return false;69 } else if (*Position == '\'') {70 if (!parseSingleQuotedStringInto(String)) return false;71 } else {72 if (!parseFreeStringInto(String)) return false;73 }74 } while (*Position != ' ');75 return true;76 }77 78 bool parseDoubleQuotedStringInto(std::string &String) {79 if (!next()) return false;80 while (*Position != '"') {81 if (!skipEscapeCharacter()) return false;82 String.push_back(*Position);83 if (!next()) return false;84 }85 return next();86 }87 88 bool parseSingleQuotedStringInto(std::string &String) {89 if (!next()) return false;90 while (*Position != '\'') {91 String.push_back(*Position);92 if (!next()) return false;93 }94 return next();95 }96 97 bool parseFreeStringInto(std::string &String) {98 do {99 if (!skipEscapeCharacter()) return false;100 String.push_back(*Position);101 if (!next()) return false;102 } while (*Position != ' ' && *Position != '"' && *Position != '\'');103 return true;104 }105 106 bool skipEscapeCharacter() {107 if (*Position == '\\') {108 return next();109 }110 return true;111 }112 113 bool nextNonWhitespace() {114 do {115 if (!next()) return false;116 } while (*Position == ' ');117 return true;118 }119 120 bool next() {121 ++Position;122 return Position != Input.end();123 }124 125 const StringRef Input;126 StringRef::iterator Position;127 std::vector<std::string> CommandLine;128};129 130std::vector<std::string> unescapeCommandLine(JSONCommandLineSyntax Syntax,131 StringRef EscapedCommandLine) {132 if (Syntax == JSONCommandLineSyntax::AutoDetect) {133#ifdef _WIN32134 // Assume Windows command line parsing on Win32135 Syntax = JSONCommandLineSyntax::Windows;136#else137 Syntax = JSONCommandLineSyntax::Gnu;138#endif139 }140 141 if (Syntax == JSONCommandLineSyntax::Windows) {142 llvm::BumpPtrAllocator Alloc;143 llvm::StringSaver Saver(Alloc);144 llvm::SmallVector<const char *, 64> T;145 llvm::cl::TokenizeWindowsCommandLine(EscapedCommandLine, Saver, T);146 std::vector<std::string> Result(T.begin(), T.end());147 return Result;148 }149 assert(Syntax == JSONCommandLineSyntax::Gnu);150 CommandLineArgumentParser parser(EscapedCommandLine);151 return parser.parse();152}153 154// This plugin locates a nearby compile_command.json file, and also infers155// compile commands for files not present in the database.156class JSONCompilationDatabasePlugin : public CompilationDatabasePlugin {157 std::unique_ptr<CompilationDatabase>158 loadFromDirectory(StringRef Directory, std::string &ErrorMessage) override {159 SmallString<1024> JSONDatabasePath(Directory);160 llvm::sys::path::append(JSONDatabasePath, "compile_commands.json");161 auto Base = JSONCompilationDatabase::loadFromFile(162 JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect);163 return Base ? inferTargetAndDriverMode(164 inferMissingCompileCommands(expandResponseFiles(165 std::move(Base), llvm::vfs::getRealFileSystem())))166 : nullptr;167 }168};169 170} // namespace171 172// Register the JSONCompilationDatabasePlugin with the173// CompilationDatabasePluginRegistry using this statically initialized variable.174static CompilationDatabasePluginRegistry::Add<JSONCompilationDatabasePlugin>175X("json-compilation-database", "Reads JSON formatted compilation databases");176 177namespace clang {178namespace tooling {179 180// This anchor is used to force the linker to link in the generated object file181// and thus register the JSONCompilationDatabasePlugin.182volatile int JSONAnchorSource = 0;183 184} // namespace tooling185} // namespace clang186 187std::unique_ptr<JSONCompilationDatabase>188JSONCompilationDatabase::loadFromFile(StringRef FilePath,189 std::string &ErrorMessage,190 JSONCommandLineSyntax Syntax) {191 // Don't mmap: if we're a long-lived process, the build system may overwrite.192 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> DatabaseBuffer =193 llvm::MemoryBuffer::getFile(FilePath, /*IsText=*/false,194 /*RequiresNullTerminator=*/true,195 /*IsVolatile=*/true);196 if (std::error_code Result = DatabaseBuffer.getError()) {197 ErrorMessage = "Error while opening JSON database: " + Result.message();198 return nullptr;199 }200 std::unique_ptr<JSONCompilationDatabase> Database(201 new JSONCompilationDatabase(std::move(*DatabaseBuffer), Syntax));202 if (!Database->parse(ErrorMessage))203 return nullptr;204 return Database;205}206 207std::unique_ptr<JSONCompilationDatabase>208JSONCompilationDatabase::loadFromBuffer(StringRef DatabaseString,209 std::string &ErrorMessage,210 JSONCommandLineSyntax Syntax) {211 std::unique_ptr<llvm::MemoryBuffer> DatabaseBuffer(212 llvm::MemoryBuffer::getMemBufferCopy(DatabaseString));213 std::unique_ptr<JSONCompilationDatabase> Database(214 new JSONCompilationDatabase(std::move(DatabaseBuffer), Syntax));215 if (!Database->parse(ErrorMessage))216 return nullptr;217 return Database;218}219 220std::vector<CompileCommand>221JSONCompilationDatabase::getCompileCommands(StringRef FilePath) const {222 SmallString<128> NativeFilePath;223 llvm::sys::path::native(FilePath, NativeFilePath);224 225 std::string Error;226 llvm::raw_string_ostream ES(Error);227 StringRef Match = MatchTrie.findEquivalent(NativeFilePath, ES);228 if (Match.empty())229 return {};230 const auto CommandsRefI = IndexByFile.find(Match);231 if (CommandsRefI == IndexByFile.end())232 return {};233 std::vector<CompileCommand> Commands;234 getCommands(CommandsRefI->getValue(), Commands);235 return Commands;236}237 238std::vector<std::string>239JSONCompilationDatabase::getAllFiles() const {240 std::vector<std::string> Result;241 for (const auto &CommandRef : IndexByFile)242 Result.push_back(CommandRef.first().str());243 return Result;244}245 246std::vector<CompileCommand>247JSONCompilationDatabase::getAllCompileCommands() const {248 std::vector<CompileCommand> Commands;249 getCommands(AllCommands, Commands);250 return Commands;251}252 253static llvm::StringRef stripExecutableExtension(llvm::StringRef Name) {254 Name.consume_back(".exe");255 return Name;256}257 258// There are compiler-wrappers (ccache, distcc) that take the "real"259// compiler as an argument, e.g. distcc gcc -O3 foo.c.260// These end up in compile_commands.json when people set CC="distcc gcc".261// Clang's driver doesn't understand this, so we need to unwrap.262static bool unwrapCommand(std::vector<std::string> &Args) {263 if (Args.size() < 2)264 return false;265 StringRef Wrapper =266 stripExecutableExtension(llvm::sys::path::filename(Args.front()));267 if (Wrapper == "distcc" || Wrapper == "ccache" || Wrapper == "sccache") {268 // Most of these wrappers support being invoked 3 ways:269 // `distcc g++ file.c` This is the mode we're trying to match.270 // We need to drop `distcc`.271 // `distcc file.c` This acts like compiler is cc or similar.272 // Clang's driver can handle this, no change needed.273 // `g++ file.c` g++ is a symlink to distcc.274 // We don't even notice this case, and all is well.275 //276 // We need to distinguish between the first and second case.277 // The wrappers themselves don't take flags, so Args[1] is a compiler flag,278 // an input file, or a compiler. Inputs have extensions, compilers don't.279 bool HasCompiler =280 (Args[1][0] != '-') &&281 !llvm::sys::path::has_extension(stripExecutableExtension(Args[1]));282 if (HasCompiler) {283 Args.erase(Args.begin());284 return true;285 }286 // If !HasCompiler, wrappers act like GCC. Fine: so do we.287 }288 return false;289}290 291static std::vector<std::string>292nodeToCommandLine(JSONCommandLineSyntax Syntax,293 const std::vector<llvm::yaml::ScalarNode *> &Nodes) {294 SmallString<1024> Storage;295 std::vector<std::string> Arguments;296 if (Nodes.size() == 1)297 Arguments = unescapeCommandLine(Syntax, Nodes[0]->getValue(Storage));298 else299 for (const auto *Node : Nodes)300 Arguments.push_back(std::string(Node->getValue(Storage)));301 // There may be multiple wrappers: using distcc and ccache together is common.302 while (unwrapCommand(Arguments))303 ;304 return Arguments;305}306 307void JSONCompilationDatabase::getCommands(308 ArrayRef<CompileCommandRef> CommandsRef,309 std::vector<CompileCommand> &Commands) const {310 for (const auto &CommandRef : CommandsRef) {311 SmallString<8> DirectoryStorage;312 SmallString<32> FilenameStorage;313 SmallString<32> OutputStorage;314 auto Output = std::get<3>(CommandRef);315 Commands.emplace_back(316 std::get<0>(CommandRef)->getValue(DirectoryStorage),317 std::get<1>(CommandRef)->getValue(FilenameStorage),318 nodeToCommandLine(Syntax, std::get<2>(CommandRef)),319 Output ? Output->getValue(OutputStorage) : "");320 }321}322 323bool JSONCompilationDatabase::parse(std::string &ErrorMessage) {324 llvm::yaml::document_iterator I = YAMLStream.begin();325 if (I == YAMLStream.end()) {326 ErrorMessage = "Error while parsing YAML.";327 return false;328 }329 llvm::yaml::Node *Root = I->getRoot();330 if (!Root) {331 ErrorMessage = "Error while parsing YAML.";332 return false;333 }334 auto *Array = dyn_cast<llvm::yaml::SequenceNode>(Root);335 if (!Array) {336 ErrorMessage = "Expected array.";337 return false;338 }339 for (auto &NextObject : *Array) {340 auto *Object = dyn_cast<llvm::yaml::MappingNode>(&NextObject);341 if (!Object) {342 ErrorMessage = "Expected object.";343 return false;344 }345 llvm::yaml::ScalarNode *Directory = nullptr;346 std::optional<std::vector<llvm::yaml::ScalarNode *>> Command;347 llvm::yaml::ScalarNode *File = nullptr;348 llvm::yaml::ScalarNode *Output = nullptr;349 for (auto& NextKeyValue : *Object) {350 auto *KeyString = dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey());351 if (!KeyString) {352 ErrorMessage = "Expected strings as key.";353 return false;354 }355 SmallString<10> KeyStorage;356 StringRef KeyValue = KeyString->getValue(KeyStorage);357 llvm::yaml::Node *Value = NextKeyValue.getValue();358 if (!Value) {359 ErrorMessage = "Expected value.";360 return false;361 }362 auto *ValueString = dyn_cast<llvm::yaml::ScalarNode>(Value);363 auto *SequenceString = dyn_cast<llvm::yaml::SequenceNode>(Value);364 if (KeyValue == "arguments") {365 if (!SequenceString) {366 ErrorMessage = "Expected sequence as value.";367 return false;368 }369 Command = std::vector<llvm::yaml::ScalarNode *>();370 for (auto &Argument : *SequenceString) {371 auto *Scalar = dyn_cast<llvm::yaml::ScalarNode>(&Argument);372 if (!Scalar) {373 ErrorMessage = "Only strings are allowed in 'arguments'.";374 return false;375 }376 Command->push_back(Scalar);377 }378 } else {379 if (!ValueString) {380 ErrorMessage = "Expected string as value.";381 return false;382 }383 if (KeyValue == "directory") {384 Directory = ValueString;385 } else if (KeyValue == "command") {386 if (!Command)387 Command = std::vector<llvm::yaml::ScalarNode *>(1, ValueString);388 } else if (KeyValue == "file") {389 File = ValueString;390 } else if (KeyValue == "output") {391 Output = ValueString;392 } else {393 ErrorMessage =394 ("Unknown key: \"" + KeyString->getRawValue() + "\"").str();395 return false;396 }397 }398 }399 if (!File) {400 ErrorMessage = "Missing key: \"file\".";401 return false;402 }403 if (!Command) {404 ErrorMessage = "Missing key: \"command\" or \"arguments\".";405 return false;406 }407 if (!Directory) {408 ErrorMessage = "Missing key: \"directory\".";409 return false;410 }411 SmallString<8> FileStorage;412 StringRef FileName = File->getValue(FileStorage);413 SmallString<128> NativeFilePath;414 if (llvm::sys::path::is_relative(FileName)) {415 SmallString<8> DirectoryStorage;416 SmallString<128> AbsolutePath(Directory->getValue(DirectoryStorage));417 llvm::sys::path::append(AbsolutePath, FileName);418 llvm::sys::path::native(AbsolutePath, NativeFilePath);419 } else {420 llvm::sys::path::native(FileName, NativeFilePath);421 }422 llvm::sys::path::remove_dots(NativeFilePath, /*remove_dot_dot=*/true);423 auto Cmd = CompileCommandRef(Directory, File, *Command, Output);424 IndexByFile[NativeFilePath].push_back(Cmd);425 AllCommands.push_back(Cmd);426 MatchTrie.insert(NativeFilePath);427 }428 return true;429}430