[VFS] Port tooling to use the in-memory file system.

[bkramer]

Summary

This means file remappings can now be managed by ClangTool (or a
ToolInvocation user) instead of by ToolInvocation itself. The
ToolInvocation remapping is still in place so users can migrate.

[bkramer]

• Don't rebuild VFS for every compile command
• Still have to guard against multiple runs of one Tool, ClangToolTest.ArgumentAdjusters does that.

[klimek]

lg

include/clang/Tooling/Tooling.h

public:
   void setDiagnosticConsumer(DiagnosticConsumer *DiagConsumer) {
     this->DiagConsumer = DiagConsumer;
   }
 
   /// \brief Map a virtual file to be used while running the tool.
   ///
   /// \param FilePath The path at which the content will be mapped.
   /// \param Content A null terminated buffer of the file's content.
+  // FIXME: remove this when all users have migrated!
   void mapVirtualFile(StringRef FilePath, StringRef Content);
 
   /// \brief Run the clang invocation.
   ///
   /// \returns True if there were no errors during execution.
   bool run();
 
  private:
public:
   /// The file manager is shared between all translation units.
   FileManager &getFiles() { return *Files; }
 
  private:
   const CompilationDatabase &Compilations;
   std::vector<std::string> SourcePaths;
   std::shared_ptr<PCHContainerOperations> PCHContainerOps;
 
+  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem;
   llvm::IntrusiveRefCntPtr<FileManager> Files;
   // Contains a list of pairs (<file name>, <file content>).
   std::vector< std::pair<StringRef, StringRef> > MappedFileContents;
 
   ArgumentsAdjuster ArgsAdjuster;
 
   DiagnosticConsumer *DiagConsumer;
 };

lib/Tooling/Tooling.cpp

 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Option/Option.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/raw_ostream.h"
 
-// For chdir, see the comment in ClangTool::run for more information.
-#ifdef LLVM_ON_WIN32
-#  include <direct.h>
-#else
-#  include <unistd.h>
-#endif
-
 #define DEBUG_TYPE "clang-tooling"
 
 namespace clang {
 namespace tooling {
 
 ToolAction::~ToolAction() {}
 
 FrontendActionFactory::~FrontendActionFactory() {}

 bool runToolOnCodeWithArgs(
     clang::FrontendAction *ToolAction, const Twine &Code,
     const std::vector<std::string> &Args, const Twine &FileName,
     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
     const FileContentMappings &VirtualMappedFiles) {
 
   SmallString<16> FileNameStorage;
   StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);
+  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
+      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new vfs::InMemoryFileSystem);
+  OverlayFileSystem->pushOverlay(InMemoryFileSystem);
   llvm::IntrusiveRefCntPtr<FileManager> Files(
-      new FileManager(FileSystemOptions()));
+      new FileManager(FileSystemOptions(), OverlayFileSystem));
   ToolInvocation Invocation(getSyntaxOnlyToolArgs(Args, FileNameRef),
                             ToolAction, Files.get(), PCHContainerOps);
 
   SmallString<1024> CodeStorage;
-  Invocation.mapVirtualFile(FileNameRef,
-                            Code.toNullTerminatedStringRef(CodeStorage));
+  InMemoryFileSystem->addFile(FileNameRef, 0,
+                              llvm::MemoryBuffer::getMemBuffer(
+                                  Code.toNullTerminatedStringRef(CodeStorage)));
 
   for (auto &FilenameWithContent : VirtualMappedFiles) {
-    Invocation.mapVirtualFile(FilenameWithContent.first,
-                              FilenameWithContent.second);
+    InMemoryFileSystem->addFile(
+        FilenameWithContent.first, 0,
+        llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
   }
 
   return Invocation.run();
 }
 
 std::string getAbsolutePath(StringRef File) {
   StringRef RelativePath(File);
   // FIXME: Should '.\\' be accepted on Win32?
const std::unique_ptr<clang::driver::Compilation> Compilation(
       Driver->BuildCompilation(llvm::makeArrayRef(Argv)));
   const llvm::opt::ArgStringList *const CC1Args = getCC1Arguments(
       &Diagnostics, Compilation.get());
   if (!CC1Args) {
     return false;
   }
   std::unique_ptr<clang::CompilerInvocation> Invocation(
       newInvocation(&Diagnostics, *CC1Args));
+  // FIXME: remove this when all users have migrated!
   for (const auto &It : MappedFileContents) {
     // Inject the code as the given file name into the preprocessor options.
     std::unique_ptr<llvm::MemoryBuffer> Input =
         llvm::MemoryBuffer::getMemBuffer(It.getValue());
     Invocation->getPreprocessorOpts().addRemappedFile(It.getKey(),
                                                       Input.release());
   }
   return runInvocation(BinaryName, Compilation.get(), Invocation.release(),
bool FrontendActionFactory::runInvocation(
   return Success;
 }
 
 ClangTool::ClangTool(const CompilationDatabase &Compilations,
                      ArrayRef<std::string> SourcePaths,
                      std::shared_ptr<PCHContainerOperations> PCHContainerOps)
     : Compilations(Compilations), SourcePaths(SourcePaths),
       PCHContainerOps(PCHContainerOps),
-      Files(new FileManager(FileSystemOptions())), DiagConsumer(nullptr) {
+      OverlayFileSystem(new vfs::OverlayFileSystem(vfs::getRealFileSystem())),
+      Files(new FileManager(FileSystemOptions(), OverlayFileSystem)),
+      DiagConsumer(nullptr) {
+  // Insert a dummy file system that is overwritten later.
+  OverlayFileSystem->pushOverlay(new vfs::InMemoryFileSystem);
   appendArgumentsAdjuster(getClangStripOutputAdjuster());
   appendArgumentsAdjuster(getClangSyntaxOnlyAdjuster());
 }
 
 ClangTool::~ClangTool() {}
 
 void ClangTool::mapVirtualFile(StringRef FilePath, StringRef Content) {
   MappedFileContents.push_back(std::make_pair(FilePath, Content));
if (CompileCommandsForFile.empty()) {
       // "find . -name '*.cc' |xargs tool" match, where as a user I don't care
       // about the .cc files that were not found, and the use case where I
       // specify all files I want to run over explicitly, where this should
       // be an error. We'll want to add an option for this.
       llvm::errs() << "Skipping " << File << ". Compile command not found.\n";
       continue;
     }
     for (CompileCommand &CompileCommand : CompileCommandsForFile) {
+      // Create a new in-memory file system for virtual files.
+      // FIXME: It would be nice if we could avoid recreating this every time.
+      llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
+          new vfs::InMemoryFileSystem);
+      *OverlayFileSystem->overlays_begin() = InMemoryFileSystem;
+
       // FIXME: chdir is thread hostile; on the other hand, creating the same
       // behavior as chdir is complex: chdir resolves the path once, thus
       // guaranteeing that all subsequent relative path operations work
       // on the same path the original chdir resulted in. This makes a
       // difference for example on network filesystems, where symlinks might be
       // switched during runtime of the tool. Fixing this depends on having a
       // file system abstraction that allows openat() style interactions.
-      if (chdir(CompileCommand.Directory.c_str()))
+      if (OverlayFileSystem->setCurrentWorkingDirectory(
+              CompileCommand.Directory))
         llvm::report_fatal_error("Cannot chdir into \"" +
                                  Twine(CompileCommand.Directory) + "\n!");
+
+      // Now fill the in-memory VFS with the file mappings so it will have the
+      // correct relative paths.
+      for (const auto &MappedFile : MappedFileContents)
+        InMemoryFileSystem->addFile(
+            MappedFile.first, 0,
+            llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
+
       std::vector<std::string> CommandLine = CompileCommand.CommandLine;
       if (ArgsAdjuster)
         CommandLine = ArgsAdjuster(CommandLine);
       assert(!CommandLine.empty());
       CommandLine[0] = MainExecutable;
       // FIXME: We need a callback mechanism for the tool writer to output a
       // customized message for each file.
       DEBUG({ llvm::dbgs() << "Processing: " << File << ".\n"; });
       ToolInvocation Invocation(std::move(CommandLine), Action, Files.get(),
                                 PCHContainerOps);
       Invocation.setDiagnosticConsumer(DiagConsumer);
-      for (const auto &MappedFile : MappedFileContents)
-        Invocation.mapVirtualFile(MappedFile.first, MappedFile.second);
+
       if (!Invocation.run()) {
         // FIXME: Diagnostics should be used instead.
         llvm::errs() << "Error while processing " << File << ".\n";
         ProcessingFailed = true;
       }
       // Return to the initial directory to correctly resolve next file by
       // relative path.
-      if (chdir(InitialDirectory.c_str()))
+      if (OverlayFileSystem->setCurrentWorkingDirectory(InitialDirectory.c_str()))
         llvm::report_fatal_error("Cannot chdir into \"" +
                                  Twine(InitialDirectory) + "\n!");
     }
   }
   return ProcessingFailed ? 1 : 0;
 }
 
 namespace {
std::unique_ptr<ASTUnit> buildASTFromCodeWithArgs(
     const Twine &Code, const std::vector<std::string> &Args,
     const Twine &FileName,
     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
   SmallString<16> FileNameStorage;
   StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);
 
   std::vector<std::unique_ptr<ASTUnit>> ASTs;
   ASTBuilderAction Action(ASTs);
+  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
+      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new vfs::InMemoryFileSystem);
+  OverlayFileSystem->pushOverlay(InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<FileManager> Files(
+      new FileManager(FileSystemOptions(), OverlayFileSystem));
   ToolInvocation Invocation(getSyntaxOnlyToolArgs(Args, FileNameRef), &Action,
-                            nullptr, PCHContainerOps);
+                            Files.get(), PCHContainerOps);
 
   SmallString<1024> CodeStorage;
-  Invocation.mapVirtualFile(FileNameRef,
-                            Code.toNullTerminatedStringRef(CodeStorage));
+  InMemoryFileSystem->addFile(FileNameRef, 0,
+                              llvm::MemoryBuffer::getMemBuffer(
+                                  Code.toNullTerminatedStringRef(CodeStorage)));
   if (!Invocation.run())
     return nullptr;
 
   assert(ASTs.size() == 1);
   return std::move(ASTs[0]);
 }
 
 } // end namespace tooling
 } // end namespace clang

unittests/Tooling/ToolingTest.cpp

TEST(newFrontendActionFactory, CreatesFrontendActionFactoryFromFactoryType) {
   IndependentFrontendActionCreator Creator;
   std::unique_ptr<FrontendActionFactory> Factory(
       newFrontendActionFactory(&Creator));
   std::unique_ptr<FrontendAction> Action(Factory->create());
   EXPECT_TRUE(Action.get() != nullptr);
 }
 
 TEST(ToolInvocation, TestMapVirtualFile) {
-  IntrusiveRefCntPtr<clang::FileManager> Files(
-      new clang::FileManager(clang::FileSystemOptions()));
+  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
+      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new vfs::InMemoryFileSystem);
+  OverlayFileSystem->pushOverlay(InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<FileManager> Files(
+      new FileManager(FileSystemOptions(), OverlayFileSystem));
   std::vector<std::string> Args;
   Args.push_back("tool-executable");
   Args.push_back("-Idef");
   Args.push_back("-fsyntax-only");
   Args.push_back("test.cpp");
   clang::tooling::ToolInvocation Invocation(Args, new SyntaxOnlyAction,
                                             Files.get());
-  Invocation.mapVirtualFile("test.cpp", "#include <abc>\n");
-  Invocation.mapVirtualFile("def/abc", "\n");
+  InMemoryFileSystem->addFile(
+      "test.cpp", 0, llvm::MemoryBuffer::getMemBuffer("#include <abc>\n"));
+  InMemoryFileSystem->addFile("def/abc", 0,
+                              llvm::MemoryBuffer::getMemBuffer("\n"));
   EXPECT_TRUE(Invocation.run());
 }
 
 TEST(ToolInvocation, TestVirtualModulesCompilation) {
   // FIXME: Currently, this only tests that we don't exit with an error if a
   // mapped module.map is found on the include path. In the future, expand this
   // test to run a full modules enabled compilation, so we make sure we can
   // rerun modules compilations with a virtual file system.
-  IntrusiveRefCntPtr<clang::FileManager> Files(
-      new clang::FileManager(clang::FileSystemOptions()));
+  llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
+      new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
+  llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
+      new vfs::InMemoryFileSystem);
+  OverlayFileSystem->pushOverlay(InMemoryFileSystem);
+  llvm::IntrusiveRefCntPtr<FileManager> Files(
+      new FileManager(FileSystemOptions(), OverlayFileSystem));
   std::vector<std::string> Args;
   Args.push_back("tool-executable");
   Args.push_back("-Idef");
   Args.push_back("-fsyntax-only");
   Args.push_back("test.cpp");
   clang::tooling::ToolInvocation Invocation(Args, new SyntaxOnlyAction,
                                             Files.get());
-  Invocation.mapVirtualFile("test.cpp", "#include <abc>\n");
-  Invocation.mapVirtualFile("def/abc", "\n");
+  InMemoryFileSystem->addFile(
+      "test.cpp", 0, llvm::MemoryBuffer::getMemBuffer("#include <abc>\n"));
+  InMemoryFileSystem->addFile("def/abc", 0,
+                              llvm::MemoryBuffer::getMemBuffer("\n"));
   // Add a module.map file in the include directory of our header, so we trigger
   // the module.map header search logic.
-  Invocation.mapVirtualFile("def/module.map", "\n");
+  InMemoryFileSystem->addFile("def/module.map", 0,
+                              llvm::MemoryBuffer::getMemBuffer("\n"));
   EXPECT_TRUE(Invocation.run());
 }
 
 struct VerifyEndCallback : public SourceFileCallbacks {
   VerifyEndCallback() : BeginCalled(0), EndCalled(0), Matched(false) {}
   bool handleBeginSource(CompilerInstance &CI, StringRef Filename) override {
     ++BeginCalled;
     return true;