clang/lib/Tooling/Tooling.cpp

   1 //===- Tooling.cpp - Running clang standalone tools -----------------------===//
   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 implements functions to run clang tools standalone instead
  10 //  of running them as a plugin.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/Tooling/Tooling.h"
  15 #include "clang/Basic/Diagnostic.h"
  16 #include "clang/Basic/DiagnosticIDs.h"
  17 #include "clang/Basic/DiagnosticOptions.h"
  18 #include "clang/Basic/FileManager.h"
  19 #include "clang/Basic/FileSystemOptions.h"
  20 #include "clang/Basic/LLVM.h"
  21 #include "clang/Driver/Compilation.h"
  22 #include "clang/Driver/Driver.h"
  23 #include "clang/Driver/Job.h"
  24 #include "clang/Driver/Options.h"
  25 #include "clang/Driver/Tool.h"
  26 #include "clang/Driver/ToolChain.h"
  27 #include "clang/Frontend/ASTUnit.h"
  28 #include "clang/Frontend/CompilerInstance.h"
  29 #include "clang/Frontend/CompilerInvocation.h"
  30 #include "clang/Frontend/FrontendDiagnostic.h"
  31 #include "clang/Frontend/FrontendOptions.h"
  32 #include "clang/Frontend/TextDiagnosticPrinter.h"
  33 #include "clang/Lex/HeaderSearchOptions.h"
  34 #include "clang/Lex/PreprocessorOptions.h"
  35 #include "clang/Tooling/ArgumentsAdjusters.h"
  36 #include "clang/Tooling/CompilationDatabase.h"
  37 #include "llvm/ADT/ArrayRef.h"
  38 #include "llvm/ADT/IntrusiveRefCntPtr.h"
  39 #include "llvm/ADT/SmallString.h"
  40 #include "llvm/ADT/StringRef.h"
  41 #include "llvm/ADT/Twine.h"
  42 #include "llvm/Option/ArgList.h"
  43 #include "llvm/Option/OptTable.h"
  44 #include "llvm/Option/Option.h"
  45 #include "llvm/Support/Casting.h"
  46 #include "llvm/Support/Debug.h"
  47 #include "llvm/Support/ErrorHandling.h"
  48 #include "llvm/Support/FileSystem.h"
  49 #include "llvm/Support/MemoryBuffer.h"
  50 #include "llvm/Support/Path.h"
  51 #include "llvm/Support/VirtualFileSystem.h"
  52 #include "llvm/Support/raw_ostream.h"
  53 #include "llvm/TargetParser/Host.h"
  54 #include <cassert>
  55 #include <cstring>
  56 #include <memory>
  57 #include <string>
  58 #include <system_error>
  59 #include <utility>
  60 #include <vector>
  61
  62 #define DEBUG_TYPE "clang-tooling"
  63
  64 using namespace clang;
  65 using namespace tooling;
  66
  67 ToolAction::~ToolAction() = default;
  68
  69 FrontendActionFactory::~FrontendActionFactory() = default;
  70
  71 // FIXME: This file contains structural duplication with other parts of the
  72 // code that sets up a compiler to run tools on it, and we should refactor
  73 // it to be based on the same framework.
  74
  75 /// Builds a clang driver initialized for running clang tools.
  76 static driver::Driver *
  77 newDriver(DiagnosticsEngine *Diagnostics, const char *BinaryName,
  78           IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
  79   driver::Driver *CompilerDriver =
  80       new driver::Driver(BinaryName, llvm::sys::getDefaultTargetTriple(),
  81                          *Diagnostics, "clang LLVM compiler", std::move(VFS));
  82   CompilerDriver->setTitle("clang_based_tool");
  83   return CompilerDriver;
  84 }
  85
  86 /// Decide whether extra compiler frontend commands can be ignored.
  87 static bool ignoreExtraCC1Commands(const driver::Compilation *Compilation) {
  88   const driver::JobList &Jobs = Compilation->getJobs();
  89   const driver::ActionList &Actions = Compilation->getActions();
  90
  91   bool OffloadCompilation = false;
  92
  93   // Jobs and Actions look very different depending on whether the Clang tool
  94   // injected -fsyntax-only or not. Try to handle both cases here.
  95
  96   for (const auto &Job : Jobs)
  97     if (StringRef(Job.getExecutable()) == "clang-offload-bundler")
  98       OffloadCompilation = true;
  99
 100   if (Jobs.size() > 1) {
 101     for (auto *A : Actions){
 102       // On MacOSX real actions may end up being wrapped in BindArchAction
 103       if (isa<driver::BindArchAction>(A))
 104         A = *A->input_begin();
 105       if (isa<driver::OffloadAction>(A)) {
 106         // Offload compilation has 2 top-level actions, one (at the front) is
 107         // the original host compilation and the other is offload action
 108         // composed of at least one device compilation. For such case, general
 109         // tooling will consider host-compilation only. For tooling on device
 110         // compilation, device compilation only option, such as
 111         // `--cuda-device-only`, needs specifying.
 112         assert(Actions.size() > 1);
 113         assert(
 114             isa<driver::CompileJobAction>(Actions.front()) ||
 115             // On MacOSX real actions may end up being wrapped in
 116             // BindArchAction.
 117             (isa<driver::BindArchAction>(Actions.front()) &&
 118              isa<driver::CompileJobAction>(*Actions.front()->input_begin())));
 119         OffloadCompilation = true;
 120         break;
 121       }
 122     }
 123   }
 124
 125   return OffloadCompilation;
 126 }
 127
 128 namespace clang {
 129 namespace tooling {
 130
 131 const llvm::opt::ArgStringList *
 132 getCC1Arguments(DiagnosticsEngine *Diagnostics,
 133                 driver::Compilation *Compilation) {
 134   const driver::JobList &Jobs = Compilation->getJobs();
 135
 136   auto IsCC1Command = [](const driver::Command &Cmd) {
 137     return StringRef(Cmd.getCreator().getName()) == "clang";
 138   };
 139
 140   auto IsSrcFile = [](const driver::InputInfo &II) {
 141     return isSrcFile(II.getType());
 142   };
 143
 144   llvm::SmallVector<const driver::Command *, 1> CC1Jobs;
 145   for (const driver::Command &Job : Jobs)
 146     if (IsCC1Command(Job) && llvm::all_of(Job.getInputInfos(), IsSrcFile))
 147       CC1Jobs.push_back(&Job);
 148
 149   if (CC1Jobs.empty() ||
 150       (CC1Jobs.size() > 1 && !ignoreExtraCC1Commands(Compilation))) {
 151     SmallString<256> error_msg;
 152     llvm::raw_svector_ostream error_stream(error_msg);
 153     Jobs.Print(error_stream, "; ", true);
 154     Diagnostics->Report(diag::err_fe_expected_compiler_job)
 155         << error_stream.str();
 156     return nullptr;
 157   }
 158
 159   return &CC1Jobs[0]->getArguments();
 160 }
 161
 162 /// Returns a clang build invocation initialized from the CC1 flags.
 163 CompilerInvocation *newInvocation(DiagnosticsEngine *Diagnostics,
 164                                   ArrayRef<const char *> CC1Args,
 165                                   const char *const BinaryName) {
 166   assert(!CC1Args.empty() && "Must at least contain the program name!");
 167   CompilerInvocation *Invocation = new CompilerInvocation;
 168   CompilerInvocation::CreateFromArgs(*Invocation, CC1Args, *Diagnostics,
 169                                      BinaryName);
 170   Invocation->getFrontendOpts().DisableFree = false;
 171   Invocation->getCodeGenOpts().DisableFree = false;
 172   return Invocation;
 173 }
 174
 175 bool runToolOnCode(std::unique_ptr<FrontendAction> ToolAction,
 176                    const Twine &Code, const Twine &FileName,
 177                    std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
 178   return runToolOnCodeWithArgs(std::move(ToolAction), Code,
 179                                std::vector<std::string>(), FileName,
 180                                "clang-tool", std::move(PCHContainerOps));
 181 }
 182
 183 } // namespace tooling
 184 } // namespace clang
 185
 186 static std::vector<std::string>
 187 getSyntaxOnlyToolArgs(const Twine &ToolName,
 188                       const std::vector<std::string> &ExtraArgs,
 189                       StringRef FileName) {
 190   std::vector<std::string> Args;
 191   Args.push_back(ToolName.str());
 192   Args.push_back("-fsyntax-only");
 193   Args.insert(Args.end(), ExtraArgs.begin(), ExtraArgs.end());
 194   Args.push_back(FileName.str());
 195   return Args;
 196 }
 197
 198 namespace clang {
 199 namespace tooling {
 200
 201 bool runToolOnCodeWithArgs(
 202     std::unique_ptr<FrontendAction> ToolAction, const Twine &Code,
 203     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
 204     const std::vector<std::string> &Args, const Twine &FileName,
 205     const Twine &ToolName,
 206     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
 207   SmallString<16> FileNameStorage;
 208   StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);
 209
 210   llvm::IntrusiveRefCntPtr<FileManager> Files(
 211       new FileManager(FileSystemOptions(), VFS));
 212   ArgumentsAdjuster Adjuster = getClangStripDependencyFileAdjuster();
 213   ToolInvocation Invocation(
 214       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileNameRef), FileNameRef),
 215       std::move(ToolAction), Files.get(), std::move(PCHContainerOps));
 216   return Invocation.run();
 217 }
 218
 219 bool runToolOnCodeWithArgs(
 220     std::unique_ptr<FrontendAction> ToolAction, const Twine &Code,
 221     const std::vector<std::string> &Args, const Twine &FileName,
 222     const Twine &ToolName,
 223     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
 224     const FileContentMappings &VirtualMappedFiles) {
 225   llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
 226       new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
 227   llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
 228       new llvm::vfs::InMemoryFileSystem);
 229   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
 230
 231   SmallString<1024> CodeStorage;
 232   InMemoryFileSystem->addFile(FileName, 0,
 233                               llvm::MemoryBuffer::getMemBuffer(
 234                                   Code.toNullTerminatedStringRef(CodeStorage)));
 235
 236   for (auto &FilenameWithContent : VirtualMappedFiles) {
 237     InMemoryFileSystem->addFile(
 238         FilenameWithContent.first, 0,
 239         llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
 240   }
 241
 242   return runToolOnCodeWithArgs(std::move(ToolAction), Code, OverlayFileSystem,
 243                                Args, FileName, ToolName);
 244 }
 245
 246 llvm::Expected<std::string> getAbsolutePath(llvm::vfs::FileSystem &FS,
 247                                             StringRef File) {
 248   StringRef RelativePath(File);
 249   // FIXME: Should '.\\' be accepted on Win32?
 250   if (RelativePath.startswith("./")) {
 251     RelativePath = RelativePath.substr(strlen("./"));
 252   }
 253
 254   SmallString<1024> AbsolutePath = RelativePath;
 255   if (auto EC = FS.makeAbsolute(AbsolutePath))
 256     return llvm::errorCodeToError(EC);
 257   llvm::sys::path::native(AbsolutePath);
 258   return std::string(AbsolutePath.str());
 259 }
 260
 261 std::string getAbsolutePath(StringRef File) {
 262   return llvm::cantFail(getAbsolutePath(*llvm::vfs::getRealFileSystem(), File));
 263 }
 264
 265 void addTargetAndModeForProgramName(std::vector<std::string> &CommandLine,
 266                                     StringRef InvokedAs) {
 267   if (CommandLine.empty() || InvokedAs.empty())
 268     return;
 269   const auto &Table = driver::getDriverOptTable();
 270   // --target=X
 271   const std::string TargetOPT =
 272       Table.getOption(driver::options::OPT_target).getPrefixedName();
 273   // -target X
 274   const std::string TargetOPTLegacy =
 275       Table.getOption(driver::options::OPT_target_legacy_spelling)
 276           .getPrefixedName();
 277   // --driver-mode=X
 278   const std::string DriverModeOPT =
 279       Table.getOption(driver::options::OPT_driver_mode).getPrefixedName();
 280   auto TargetMode =
 281       driver::ToolChain::getTargetAndModeFromProgramName(InvokedAs);
 282   // No need to search for target args if we don't have a target/mode to insert.
 283   bool ShouldAddTarget = TargetMode.TargetIsValid;
 284   bool ShouldAddMode = TargetMode.DriverMode != nullptr;
 285   // Skip CommandLine[0].
 286   for (auto Token = ++CommandLine.begin(); Token != CommandLine.end();
 287        ++Token) {
 288     StringRef TokenRef(*Token);
 289     ShouldAddTarget = ShouldAddTarget && !TokenRef.startswith(TargetOPT) &&
 290                       !TokenRef.equals(TargetOPTLegacy);
 291     ShouldAddMode = ShouldAddMode && !TokenRef.startswith(DriverModeOPT);
 292   }
 293   if (ShouldAddMode) {
 294     CommandLine.insert(++CommandLine.begin(), TargetMode.DriverMode);
 295   }
 296   if (ShouldAddTarget) {
 297     CommandLine.insert(++CommandLine.begin(),
 298                        TargetOPT + TargetMode.TargetPrefix);
 299   }
 300 }
 301
 302 } // namespace tooling
 303 } // namespace clang
 304
 305 namespace {
 306
 307 class SingleFrontendActionFactory : public FrontendActionFactory {
 308   std::unique_ptr<FrontendAction> Action;
 309
 310 public:
 311   SingleFrontendActionFactory(std::unique_ptr<FrontendAction> Action)
 312       : Action(std::move(Action)) {}
 313
 314   std::unique_ptr<FrontendAction> create() override {
 315     return std::move(Action);
 316   }
 317 };
 318
 319 } // namespace
 320
 321 ToolInvocation::ToolInvocation(
 322     std::vector<std::string> CommandLine, ToolAction *Action,
 323     FileManager *Files, std::shared_ptr<PCHContainerOperations> PCHContainerOps)
 324     : CommandLine(std::move(CommandLine)), Action(Action), OwnsAction(false),
 325       Files(Files), PCHContainerOps(std::move(PCHContainerOps)) {}
 326
 327 ToolInvocation::ToolInvocation(
 328     std::vector<std::string> CommandLine,
 329     std::unique_ptr<FrontendAction> FAction, FileManager *Files,
 330     std::shared_ptr<PCHContainerOperations> PCHContainerOps)
 331     : CommandLine(std::move(CommandLine)),
 332       Action(new SingleFrontendActionFactory(std::move(FAction))),
 333       OwnsAction(true), Files(Files),
 334       PCHContainerOps(std::move(PCHContainerOps)) {}
 335
 336 ToolInvocation::~ToolInvocation() {
 337   if (OwnsAction)
 338     delete Action;
 339 }
 340
 341 bool ToolInvocation::run() {
 342   llvm::opt::ArgStringList Argv;
 343   for (const std::string &Str : CommandLine)
 344     Argv.push_back(Str.c_str());
 345   const char *const BinaryName = Argv[0];
 346
 347   // Parse diagnostic options from the driver command-line only if none were
 348   // explicitly set.
 349   IntrusiveRefCntPtr<DiagnosticOptions> ParsedDiagOpts;
 350   DiagnosticOptions *DiagOpts = this->DiagOpts;
 351   if (!DiagOpts) {
 352     ParsedDiagOpts = CreateAndPopulateDiagOpts(Argv);
 353     DiagOpts = &*ParsedDiagOpts;
 354   }
 355
 356   TextDiagnosticPrinter DiagnosticPrinter(llvm::errs(), DiagOpts);
 357   IntrusiveRefCntPtr<DiagnosticsEngine> Diagnostics =
 358       CompilerInstance::createDiagnostics(
 359           &*DiagOpts, DiagConsumer ? DiagConsumer : &DiagnosticPrinter, false);
 360   // Although `Diagnostics` are used only for command-line parsing, the custom
 361   // `DiagConsumer` might expect a `SourceManager` to be present.
 362   SourceManager SrcMgr(*Diagnostics, *Files);
 363   Diagnostics->setSourceManager(&SrcMgr);
 364
 365   // We already have a cc1, just create an invocation.
 366   if (CommandLine.size() >= 2 && CommandLine[1] == "-cc1") {
 367     ArrayRef<const char *> CC1Args = ArrayRef(Argv).drop_front();
 368     std::unique_ptr<CompilerInvocation> Invocation(
 369         newInvocation(&*Diagnostics, CC1Args, BinaryName));
 370     if (Diagnostics->hasErrorOccurred())
 371       return false;
 372     return Action->runInvocation(std::move(Invocation), Files,
 373                                  std::move(PCHContainerOps), DiagConsumer);
 374   }
 375
 376   const std::unique_ptr<driver::Driver> Driver(
 377       newDriver(&*Diagnostics, BinaryName, &Files->getVirtualFileSystem()));
 378   // The "input file not found" diagnostics from the driver are useful.
 379   // The driver is only aware of the VFS working directory, but some clients
 380   // change this at the FileManager level instead.
 381   // In this case the checks have false positives, so skip them.
 382   if (!Files->getFileSystemOpts().WorkingDir.empty())
 383     Driver->setCheckInputsExist(false);
 384   const std::unique_ptr<driver::Compilation> Compilation(
 385       Driver->BuildCompilation(llvm::ArrayRef(Argv)));
 386   if (!Compilation)
 387     return false;
 388   const llvm::opt::ArgStringList *const CC1Args = getCC1Arguments(
 389       &*Diagnostics, Compilation.get());
 390   if (!CC1Args)
 391     return false;
 392   std::unique_ptr<CompilerInvocation> Invocation(
 393       newInvocation(&*Diagnostics, *CC1Args, BinaryName));
 394   return runInvocation(BinaryName, Compilation.get(), std::move(Invocation),
 395                        std::move(PCHContainerOps));
 396 }
 397
 398 bool ToolInvocation::runInvocation(
 399     const char *BinaryName, driver::Compilation *Compilation,
 400     std::shared_ptr<CompilerInvocation> Invocation,
 401     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
 402   // Show the invocation, with -v.
 403   if (Invocation->getHeaderSearchOpts().Verbose) {
 404     llvm::errs() << "clang Invocation:\n";
 405     Compilation->getJobs().Print(llvm::errs(), "\n", true);
 406     llvm::errs() << "\n";
 407   }
 408
 409   return Action->runInvocation(std::move(Invocation), Files,
 410                                std::move(PCHContainerOps), DiagConsumer);
 411 }
 412
 413 bool FrontendActionFactory::runInvocation(
 414     std::shared_ptr<CompilerInvocation> Invocation, FileManager *Files,
 415     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
 416     DiagnosticConsumer *DiagConsumer) {
 417   // Create a compiler instance to handle the actual work.
 418   CompilerInstance Compiler(std::move(PCHContainerOps));
 419   Compiler.setInvocation(std::move(Invocation));
 420   Compiler.setFileManager(Files);
 421
 422   // The FrontendAction can have lifetime requirements for Compiler or its
 423   // members, and we need to ensure it's deleted earlier than Compiler. So we
 424   // pass it to an std::unique_ptr declared after the Compiler variable.
 425   std::unique_ptr<FrontendAction> ScopedToolAction(create());
 426
 427   // Create the compiler's actual diagnostics engine.
 428   Compiler.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
 429   if (!Compiler.hasDiagnostics())
 430     return false;
 431
 432   Compiler.createSourceManager(*Files);
 433
 434   const bool Success = Compiler.ExecuteAction(*ScopedToolAction);
 435
 436   Files->clearStatCache();
 437   return Success;
 438 }
 439
 440 ClangTool::ClangTool(const CompilationDatabase &Compilations,
 441                      ArrayRef<std::string> SourcePaths,
 442                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
 443                      IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS,
 444                      IntrusiveRefCntPtr<FileManager> Files)
 445     : Compilations(Compilations), SourcePaths(SourcePaths),
 446       PCHContainerOps(std::move(PCHContainerOps)),
 447       OverlayFileSystem(new llvm::vfs::OverlayFileSystem(std::move(BaseFS))),
 448       InMemoryFileSystem(new llvm::vfs::InMemoryFileSystem),
 449       Files(Files ? Files
 450                   : new FileManager(FileSystemOptions(), OverlayFileSystem)) {
 451   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
 452   appendArgumentsAdjuster(getClangStripOutputAdjuster());
 453   appendArgumentsAdjuster(getClangSyntaxOnlyAdjuster());
 454   appendArgumentsAdjuster(getClangStripDependencyFileAdjuster());
 455   if (Files)
 456     Files->setVirtualFileSystem(OverlayFileSystem);
 457 }
 458
 459 ClangTool::~ClangTool() = default;
 460
 461 void ClangTool::mapVirtualFile(StringRef FilePath, StringRef Content) {
 462   MappedFileContents.push_back(std::make_pair(FilePath, Content));
 463 }
 464
 465 void ClangTool::appendArgumentsAdjuster(ArgumentsAdjuster Adjuster) {
 466   ArgsAdjuster = combineAdjusters(std::move(ArgsAdjuster), std::move(Adjuster));
 467 }
 468
 469 void ClangTool::clearArgumentsAdjusters() {
 470   ArgsAdjuster = nullptr;
 471 }
 472
 473 static void injectResourceDir(CommandLineArguments &Args, const char *Argv0,
 474                               void *MainAddr) {
 475   // Allow users to override the resource dir.
 476   for (StringRef Arg : Args)
 477     if (Arg.startswith("-resource-dir"))
 478       return;
 479
 480   // If there's no override in place add our resource dir.
 481   Args = getInsertArgumentAdjuster(
 482       ("-resource-dir=" + CompilerInvocation::GetResourcesPath(Argv0, MainAddr))
 483           .c_str())(Args, "");
 484 }
 485
 486 int ClangTool::run(ToolAction *Action) {
 487   // Exists solely for the purpose of lookup of the resource path.
 488   // This just needs to be some symbol in the binary.
 489   static int StaticSymbol;
 490
 491   // First insert all absolute paths into the in-memory VFS. These are global
 492   // for all compile commands.
 493   if (SeenWorkingDirectories.insert("/").second)
 494     for (const auto &MappedFile : MappedFileContents)
 495       if (llvm::sys::path::is_absolute(MappedFile.first))
 496         InMemoryFileSystem->addFile(
 497             MappedFile.first, 0,
 498             llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
 499
 500   bool ProcessingFailed = false;
 501   bool FileSkipped = false;
 502   // Compute all absolute paths before we run any actions, as those will change
 503   // the working directory.
 504   std::vector<std::string> AbsolutePaths;
 505   AbsolutePaths.reserve(SourcePaths.size());
 506   for (const auto &SourcePath : SourcePaths) {
 507     auto AbsPath = getAbsolutePath(*OverlayFileSystem, SourcePath);
 508     if (!AbsPath) {
 509       llvm::errs() << "Skipping " << SourcePath
 510                    << ". Error while getting an absolute path: "
 511                    << llvm::toString(AbsPath.takeError()) << "\n";
 512       continue;
 513     }
 514     AbsolutePaths.push_back(std::move(*AbsPath));
 515   }
 516
 517   // Remember the working directory in case we need to restore it.
 518   std::string InitialWorkingDir;
 519   if (RestoreCWD) {
 520     if (auto CWD = OverlayFileSystem->getCurrentWorkingDirectory()) {
 521       InitialWorkingDir = std::move(*CWD);
 522     } else {
 523       llvm::errs() << "Could not get working directory: "
 524                    << CWD.getError().message() << "\n";
 525     }
 526   }
 527
 528   for (llvm::StringRef File : AbsolutePaths) {
 529     // Currently implementations of CompilationDatabase::getCompileCommands can
 530     // change the state of the file system (e.g.  prepare generated headers), so
 531     // this method needs to run right before we invoke the tool, as the next
 532     // file may require a different (incompatible) state of the file system.
 533     //
 534     // FIXME: Make the compilation database interface more explicit about the
 535     // requirements to the order of invocation of its members.
 536     std::vector<CompileCommand> CompileCommandsForFile =
 537         Compilations.getCompileCommands(File);
 538     if (CompileCommandsForFile.empty()) {
 539       llvm::errs() << "Skipping " << File << ". Compile command not found.\n";
 540       FileSkipped = true;
 541       continue;
 542     }
 543     for (CompileCommand &CompileCommand : CompileCommandsForFile) {
 544       // FIXME: chdir is thread hostile; on the other hand, creating the same
 545       // behavior as chdir is complex: chdir resolves the path once, thus
 546       // guaranteeing that all subsequent relative path operations work
 547       // on the same path the original chdir resulted in. This makes a
 548       // difference for example on network filesystems, where symlinks might be
 549       // switched during runtime of the tool. Fixing this depends on having a
 550       // file system abstraction that allows openat() style interactions.
 551       if (OverlayFileSystem->setCurrentWorkingDirectory(
 552               CompileCommand.Directory))
 553         llvm::report_fatal_error("Cannot chdir into \"" +
 554                                  Twine(CompileCommand.Directory) + "\"!");
 555
 556       // Now fill the in-memory VFS with the relative file mappings so it will
 557       // have the correct relative paths. We never remove mappings but that
 558       // should be fine.
 559       if (SeenWorkingDirectories.insert(CompileCommand.Directory).second)
 560         for (const auto &MappedFile : MappedFileContents)
 561           if (!llvm::sys::path::is_absolute(MappedFile.first))
 562             InMemoryFileSystem->addFile(
 563                 MappedFile.first, 0,
 564                 llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
 565
 566       std::vector<std::string> CommandLine = CompileCommand.CommandLine;
 567       if (ArgsAdjuster)
 568         CommandLine = ArgsAdjuster(CommandLine, CompileCommand.Filename);
 569       assert(!CommandLine.empty());
 570
 571       // Add the resource dir based on the binary of this tool. argv[0] in the
 572       // compilation database may refer to a different compiler and we want to
 573       // pick up the very same standard library that compiler is using. The
 574       // builtin headers in the resource dir need to match the exact clang
 575       // version the tool is using.
 576       // FIXME: On linux, GetMainExecutable is independent of the value of the
 577       // first argument, thus allowing ClangTool and runToolOnCode to just
 578       // pass in made-up names here. Make sure this works on other platforms.
 579       injectResourceDir(CommandLine, "clang_tool", &StaticSymbol);
 580
 581       // FIXME: We need a callback mechanism for the tool writer to output a
 582       // customized message for each file.
 583       LLVM_DEBUG({ llvm::dbgs() << "Processing: " << File << ".\n"; });
 584       ToolInvocation Invocation(std::move(CommandLine), Action, Files.get(),
 585                                 PCHContainerOps);
 586       Invocation.setDiagnosticConsumer(DiagConsumer);
 587
 588       if (!Invocation.run()) {
 589         // FIXME: Diagnostics should be used instead.
 590         if (PrintErrorMessage)
 591           llvm::errs() << "Error while processing " << File << ".\n";
 592         ProcessingFailed = true;
 593       }
 594     }
 595   }
 596
 597   if (!InitialWorkingDir.empty()) {
 598     if (auto EC =
 599             OverlayFileSystem->setCurrentWorkingDirectory(InitialWorkingDir))
 600       llvm::errs() << "Error when trying to restore working dir: "
 601                    << EC.message() << "\n";
 602   }
 603   return ProcessingFailed ? 1 : (FileSkipped ? 2 : 0);
 604 }
 605
 606 namespace {
 607
 608 class ASTBuilderAction : public ToolAction {
 609   std::vector<std::unique_ptr<ASTUnit>> &ASTs;
 610
 611 public:
 612   ASTBuilderAction(std::vector<std::unique_ptr<ASTUnit>> &ASTs) : ASTs(ASTs) {}
 613
 614   bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
 615                      FileManager *Files,
 616                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
 617                      DiagnosticConsumer *DiagConsumer) override {
 618     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromCompilerInvocation(
 619         Invocation, std::move(PCHContainerOps),
 620         CompilerInstance::createDiagnostics(&Invocation->getDiagnosticOpts(),
 621                                             DiagConsumer,
 622                                             /*ShouldOwnClient=*/false),
 623         Files);
 624     if (!AST)
 625       return false;
 626
 627     ASTs.push_back(std::move(AST));
 628     return true;
 629   }
 630 };
 631
 632 } // namespace
 633
 634 int ClangTool::buildASTs(std::vector<std::unique_ptr<ASTUnit>> &ASTs) {
 635   ASTBuilderAction Action(ASTs);
 636   return run(&Action);
 637 }
 638
 639 void ClangTool::setRestoreWorkingDir(bool RestoreCWD) {
 640   this->RestoreCWD = RestoreCWD;
 641 }
 642
 643 void ClangTool::setPrintErrorMessage(bool PrintErrorMessage) {
 644   this->PrintErrorMessage = PrintErrorMessage;
 645 }
 646
 647 namespace clang {
 648 namespace tooling {
 649
 650 std::unique_ptr<ASTUnit>
 651 buildASTFromCode(StringRef Code, StringRef FileName,
 652                  std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
 653   return buildASTFromCodeWithArgs(Code, std::vector<std::string>(), FileName,
 654                                   "clang-tool", std::move(PCHContainerOps));
 655 }
 656
 657 std::unique_ptr<ASTUnit> buildASTFromCodeWithArgs(
 658     StringRef Code, const std::vector<std::string> &Args, StringRef FileName,
 659     StringRef ToolName, std::shared_ptr<PCHContainerOperations> PCHContainerOps,
 660     ArgumentsAdjuster Adjuster, const FileContentMappings &VirtualMappedFiles,
 661     DiagnosticConsumer *DiagConsumer) {
 662   std::vector<std::unique_ptr<ASTUnit>> ASTs;
 663   ASTBuilderAction Action(ASTs);
 664   llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
 665       new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
 666   llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
 667       new llvm::vfs::InMemoryFileSystem);
 668   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
 669   llvm::IntrusiveRefCntPtr<FileManager> Files(
 670       new FileManager(FileSystemOptions(), OverlayFileSystem));
 671
 672   ToolInvocation Invocation(
 673       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileName), FileName),
 674       &Action, Files.get(), std::move(PCHContainerOps));
 675   Invocation.setDiagnosticConsumer(DiagConsumer);
 676
 677   InMemoryFileSystem->addFile(FileName, 0,
 678                               llvm::MemoryBuffer::getMemBufferCopy(Code));
 679   for (auto &FilenameWithContent : VirtualMappedFiles) {
 680     InMemoryFileSystem->addFile(
 681         FilenameWithContent.first, 0,
 682         llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
 683   }
 684
 685   if (!Invocation.run())
 686     return nullptr;
 687
 688   assert(ASTs.size() == 1);
 689   return std::move(ASTs[0]);
 690 }
 691
 692 } // namespace tooling
 693 } // namespace clang