clang/lib/Tooling/JSONCompilationDatabase.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-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 }