Unify DependencyFileGenerator class and DependencyCollector interface

[arphaman]

Summary

This NFCI patch makes DependencyFileGenerator a DependencyCollector as it was intended when DependencyCollector was introduced. The missing PP overrides are added to the DependencyCollector as well.

This change will allow clang-scan-deps to access the produced dependencies without writing them out to .d files to disk, so that it will be able collate them and report them to the user.

[arphaman]

Fix the missing word in the comment.

[aganea]

clang/include/clang/Frontend/Utils.h

118 ↗

(On Diff #204611)

s/depdenency/dependency/

clang/lib/Frontend/DependencyFile.cpp

78 ↗

(On Diff #204611)

Given that llvm::sys::path::remove_leading_dotslash is not called here, but it is for the function above, could you end up with two entries in DependencyCollector::Seen when DependencyCollector::sawDependency is overriden?

165 ↗

(On Diff #204611)

Why !IsMissing wasn't considered before? Just wondering.

[arphaman]

Address review comments.

clang/lib/Frontend/DependencyFile.cpp

78 ↗

(On Diff #204611)

I think I understand the case you're describing, essentially a file skipped that has a "./foo.h" will be inserted as "foo.h", which might collide with a missing "foo.h" in DependencyCollector::Seen.

I don't think this is a problem as a skipped file must still resolve to a file on disk/vfs. Therefore, if it's found, it can't be missing, so it would be impossible for such collision to occur.

165 ↗

(On Diff #204611)

Hmm, I think that's an oversight, I thought I needed it but it looks like without it we will match the previous behavior. I removed that check.

[aganea]

LGTM.

cfe/trunk/include/clang/Frontend/CompilerInstance.h

class CompilerInstance : public ModuleLoader {
   IntrusiveRefCntPtr<ASTReader> ModuleManager;
 
   /// The module dependency collector for crashdumps
   std::shared_ptr<ModuleDependencyCollector> ModuleDepCollector;
 
   /// The module provider.
   std::shared_ptr<PCHContainerOperations> ThePCHContainerOperations;
 
-  /// The dependency file generator.
-  std::unique_ptr<DependencyFileGenerator> TheDependencyFileGenerator;
-
   std::vector<std::shared_ptr<DependencyCollector>> DependencyCollectors;
 
   /// The set of top-level modules that has already been loaded,
   /// along with the module map
   llvm::DenseMap<const IdentifierInfo *, Module *> KnownModules;
 
   /// The set of top-level modules that has already been built on the
   /// fly as part of this overall compilation action.
public:
   ///
   /// \return - The new object on success, or null on failure.
   static IntrusiveRefCntPtr<ASTReader> createPCHExternalASTSource(
       StringRef Path, StringRef Sysroot, bool DisablePCHValidation,
       bool AllowPCHWithCompilerErrors, Preprocessor &PP,
       InMemoryModuleCache &ModuleCache, ASTContext &Context,
       const PCHContainerReader &PCHContainerRdr,
       ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
-      DependencyFileGenerator *DependencyFile,
       ArrayRef<std::shared_ptr<DependencyCollector>> DependencyCollectors,
       void *DeserializationListener, bool OwnDeserializationListener,
       bool Preamble, bool UseGlobalModuleIndex);
 
   /// Create a code completion consumer using the invocation; note that this
   /// will cause the source manager to truncate the input source file at the
   /// completion point.
   void createCodeCompletionConsumer();

cfe/trunk/include/clang/Frontend/Utils.h

 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_FRONTEND_UTILS_H
 #define LLVM_CLANG_FRONTEND_UTILS_H
 
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LLVM.h"
+#include "clang/Frontend/DependencyOutputOptions.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/Option/OptSpecifier.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include <cstdint>

 
 } // namespace llvm
 
 namespace clang {
 
 class ASTReader;
 class CompilerInstance;
 class CompilerInvocation;
-class DependencyOutputOptions;
 class DiagnosticsEngine;
 class ExternalSemaSource;
 class FrontendOptions;
 class HeaderSearch;
 class HeaderSearchOptions;
 class LangOptions;
 class PCHContainerReader;
 class Preprocessor;

 
 /// DoPrintPreprocessedInput - Implement -E mode.
 void DoPrintPreprocessedInput(Preprocessor &PP, raw_ostream *OS,
                               const PreprocessorOutputOptions &Opts);
 
 /// An interface for collecting the dependencies of a compilation. Users should
 /// use \c attachToPreprocessor and \c attachToASTReader to get all of the
 /// dependencies.
-/// FIXME: Migrate DependencyFileGen and DependencyGraphGen to use this
-/// interface.
+/// FIXME: Migrate DependencyGraphGen to use this interface.
 class DependencyCollector {
 public:
   virtual ~DependencyCollector();
 
   virtual void attachToPreprocessor(Preprocessor &PP);
   virtual void attachToASTReader(ASTReader &R);
   ArrayRef<std::string> getDependencies() const { return Dependencies; }
 
   /// Called when a new file is seen. Return true if \p Filename should be added
   /// to the list of dependencies.
   ///
   /// The default implementation ignores <built-in> and system files.
   virtual bool sawDependency(StringRef Filename, bool FromModule,
                              bool IsSystem, bool IsModuleFile, bool IsMissing);
 
   /// Called when the end of the main file is reached.
-  virtual void finishedMainFile() {}
+  virtual void finishedMainFile(DiagnosticsEngine &Diags) {}
 
   /// Return true if system files should be passed to sawDependency().
   virtual bool needSystemDependencies() { return false; }
 
   // implementation detail
   /// Add a dependency \p Filename if it has not been seen before and
   /// sawDependency() returns true.
   void maybeAddDependency(StringRef Filename, bool FromModule, bool IsSystem,
                           bool IsModuleFile, bool IsMissing);
 
+protected:
+  /// Return true if the filename was added to the list of dependencies, false
+  /// otherwise.
+  bool addDependency(StringRef Filename);
+
 private:
   llvm::StringSet<> Seen;
   std::vector<std::string> Dependencies;
 };
 
-/// Builds a depdenency file when attached to a Preprocessor (for includes) and
+/// Builds a dependency file when attached to a Preprocessor (for includes) and
 /// ASTReader (for module imports), and writes it out at the end of processing
 /// a source file.  Users should attach to the ast reader whenever a module is
 /// loaded.
-class DependencyFileGenerator {
-  void *Impl; // Opaque implementation
+class DependencyFileGenerator : public DependencyCollector {
+public:
+  DependencyFileGenerator(const DependencyOutputOptions &Opts);
 
-  DependencyFileGenerator(void *Impl);
+  void attachToPreprocessor(Preprocessor &PP) override;
 
-public:
-  static DependencyFileGenerator *CreateAndAttachToPreprocessor(
-    Preprocessor &PP, const DependencyOutputOptions &Opts);
+  void finishedMainFile(DiagnosticsEngine &Diags) override;
+
+  bool needSystemDependencies() final override { return IncludeSystemHeaders; }
+
+  bool sawDependency(StringRef Filename, bool FromModule, bool IsSystem,
+                     bool IsModuleFile, bool IsMissing) final override;
+
+private:
+  void outputDependencyFile(DiagnosticsEngine &Diags);
 
-  void AttachToASTReader(ASTReader &R);
+  std::string OutputFile;
+  std::vector<std::string> Targets;
+  bool IncludeSystemHeaders;
+  bool PhonyTarget;
+  bool AddMissingHeaderDeps;
+  bool SeenMissingHeader;
+  bool IncludeModuleFiles;
+  DependencyOutputFormat OutputFormat;
+  unsigned InputFileIndex;
 };
 
 /// Collects the dependencies for imported modules into a directory.  Users
 /// should attach to the AST reader whenever a module is loaded.
 class ModuleDependencyCollector : public DependencyCollector {
   std::string DestDir;
   bool HasErrors = false;
   llvm::StringSet<> Seen;

cfe/trunk/lib/Frontend/CompilerInstance.cpp

void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
   PP->setPreprocessedOutput(getPreprocessorOutputOpts().ShowCPP);
 
   if (PP->getLangOpts().Modules && PP->getLangOpts().ImplicitModules)
     PP->getHeaderSearchInfo().setModuleCachePath(getSpecificModuleCachePath());
 
   // Handle generating dependencies, if requested.
   const DependencyOutputOptions &DepOpts = getDependencyOutputOpts();
   if (!DepOpts.OutputFile.empty())
-    TheDependencyFileGenerator.reset(
-        DependencyFileGenerator::CreateAndAttachToPreprocessor(*PP, DepOpts));
+    addDependencyCollector(std::make_shared<DependencyFileGenerator>(DepOpts));
   if (!DepOpts.DOTOutputFile.empty())
     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
                              getHeaderSearchOpts().Sysroot);
 
   // If we don't have a collector, but we are collecting module dependencies,
   // then we're the top level compiler instance and need to create one.
   if (!ModuleDepCollector && !DepOpts.ModuleDependencyOutputDir.empty()) {
     ModuleDepCollector = std::make_shared<ModuleDependencyCollector>(

 void CompilerInstance::createPCHExternalASTSource(
     StringRef Path, bool DisablePCHValidation, bool AllowPCHWithCompilerErrors,
     void *DeserializationListener, bool OwnDeserializationListener) {
   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
   ModuleManager = createPCHExternalASTSource(
       Path, getHeaderSearchOpts().Sysroot, DisablePCHValidation,
       AllowPCHWithCompilerErrors, getPreprocessor(), getModuleCache(),
       getASTContext(), getPCHContainerReader(),
-      getFrontendOpts().ModuleFileExtensions, TheDependencyFileGenerator.get(),
-      DependencyCollectors, DeserializationListener, OwnDeserializationListener,
-      Preamble, getFrontendOpts().UseGlobalModuleIndex);
+      getFrontendOpts().ModuleFileExtensions, DependencyCollectors,
+      DeserializationListener, OwnDeserializationListener, Preamble,
+      getFrontendOpts().UseGlobalModuleIndex);
 }
 
 IntrusiveRefCntPtr<ASTReader> CompilerInstance::createPCHExternalASTSource(
     StringRef Path, StringRef Sysroot, bool DisablePCHValidation,
     bool AllowPCHWithCompilerErrors, Preprocessor &PP,
     InMemoryModuleCache &ModuleCache, ASTContext &Context,
     const PCHContainerReader &PCHContainerRdr,
     ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
-    DependencyFileGenerator *DependencyFile,
     ArrayRef<std::shared_ptr<DependencyCollector>> DependencyCollectors,
     void *DeserializationListener, bool OwnDeserializationListener,
     bool Preamble, bool UseGlobalModuleIndex) {
   HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts();
 
   IntrusiveRefCntPtr<ASTReader> Reader(new ASTReader(
       PP, ModuleCache, &Context, PCHContainerRdr, Extensions,
       Sysroot.empty() ? "" : Sysroot.data(), DisablePCHValidation,
       AllowPCHWithCompilerErrors, /*AllowConfigurationMismatch*/ false,
       HSOpts.ModulesValidateSystemHeaders, UseGlobalModuleIndex));
 
   // We need the external source to be set up before we read the AST, because
   // eagerly-deserialized declarations may use it.
   Context.setExternalSource(Reader.get());
 
   Reader->setDeserializationListener(
       static_cast<ASTDeserializationListener *>(DeserializationListener),
       /*TakeOwnership=*/OwnDeserializationListener);
 
-  if (DependencyFile)
-    DependencyFile->AttachToASTReader(*Reader);
   for (auto &Listener : DependencyCollectors)
     Listener->attachToASTReader(*Reader);
 
   switch (Reader->ReadAST(Path,
                           Preamble ? serialization::MK_Preamble
                                    : serialization::MK_PCH,
                           SourceLocation(),
                           ASTReader::ARR_None)) {
if (hasASTConsumer()) {
         getASTConsumer().GetASTMutationListener());
     }
     getASTContext().setExternalSource(ModuleManager);
     if (hasSema())
       ModuleManager->InitializeSema(getSema());
     if (hasASTConsumer())
       ModuleManager->StartTranslationUnit(&getASTConsumer());
 
-    if (TheDependencyFileGenerator)
-      TheDependencyFileGenerator->AttachToASTReader(*ModuleManager);
     for (auto &Listener : DependencyCollectors)
       Listener->attachToASTReader(*ModuleManager);
   }
 }
 
 bool CompilerInstance::loadModuleFile(StringRef FileName) {
   llvm::Timer Timer;
   if (FrontendTimerGroup)

cfe/trunk/lib/Frontend/DependencyFile.cpp

 #include "llvm/Support/raw_ostream.h"
 
 using namespace clang;
 
 namespace {
 struct DepCollectorPPCallbacks : public PPCallbacks {
   DependencyCollector &DepCollector;
   SourceManager &SM;
-  DepCollectorPPCallbacks(DependencyCollector &L, SourceManager &SM)
-      : DepCollector(L), SM(SM) { }
+  DiagnosticsEngine &Diags;
+  DepCollectorPPCallbacks(DependencyCollector &L, SourceManager &SM,
+                          DiagnosticsEngine &Diags)
+      : DepCollector(L), SM(SM), Diags(Diags) {}
 
   void FileChanged(SourceLocation Loc, FileChangeReason Reason,
                    SrcMgr::CharacteristicKind FileType,
                    FileID PrevFID) override {
     if (Reason != PPCallbacks::EnterFile)
       return;
 
     // Dependency generation really does want to go all the way to the
     // file entry for a source location to find out what is depended on.
     // We do not want #line markers to affect dependency generation!
     const FileEntry *FE =
         SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
     if (!FE)
       return;
 
     StringRef Filename =
         llvm::sys::path::remove_leading_dotslash(FE->getName());
 
     DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
                                     isSystem(FileType),
                                     /*IsModuleFile*/false, /*IsMissing*/false);
   }
 
+  void FileSkipped(const FileEntry &SkippedFile, const Token &FilenameTok,
+                   SrcMgr::CharacteristicKind FileType) override {
+    StringRef Filename =
+        llvm::sys::path::remove_leading_dotslash(SkippedFile.getName());
+    DepCollector.maybeAddDependency(Filename, /*FromModule=*/false,
+                                    /*IsSystem=*/isSystem(FileType),
+                                    /*IsModuleFile=*/false,
+                                    /*IsMissing=*/false);
+  }
+
   void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
                           StringRef FileName, bool IsAngled,
                           CharSourceRange FilenameRange, const FileEntry *File,
                           StringRef SearchPath, StringRef RelativePath,
                           const Module *Imported,
                           SrcMgr::CharacteristicKind FileType) override {
     if (!File)
       DepCollector.maybeAddDependency(FileName, /*FromModule*/false,
                                      /*IsSystem*/false, /*IsModuleFile*/false,
                                      /*IsMissing*/true);
     // Files that actually exist are handled by FileChanged.
   }
 
-  void EndOfMainFile() override {
-    DepCollector.finishedMainFile();
+  void HasInclude(SourceLocation Loc, StringRef SpelledFilename, bool IsAngled,
+                  const FileEntry *File,
+                  SrcMgr::CharacteristicKind FileType) override {
+    if (!File)
+      return;
+    StringRef Filename =
+        llvm::sys::path::remove_leading_dotslash(File->getName());
+    DepCollector.maybeAddDependency(Filename, /*FromModule=*/false,
+                                    /*IsSystem=*/isSystem(FileType),
+                                    /*IsModuleFile=*/false,
+                                    /*IsMissing=*/false);
   }
+
+  void EndOfMainFile() override { DepCollector.finishedMainFile(Diags); }
 };
 
 struct DepCollectorMMCallbacks : public ModuleMapCallbacks {
   DependencyCollector &DepCollector;
   DepCollectorMMCallbacks(DependencyCollector &DC) : DepCollector(DC) {}
 
   void moduleMapFileRead(SourceLocation Loc, const FileEntry &Entry,
                          bool IsSystem) override {
bool visitInputFile(StringRef Filename, bool IsSystem,
     return true;
   }
 };
 } // end anonymous namespace
 
 void DependencyCollector::maybeAddDependency(StringRef Filename, bool FromModule,
                                             bool IsSystem, bool IsModuleFile,
                                             bool IsMissing) {
-  if (Seen.insert(Filename).second &&
-      sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
+  if (sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
+    addDependency(Filename);
+}
+
+bool DependencyCollector::addDependency(StringRef Filename) {
+  if (Seen.insert(Filename).second) {
     Dependencies.push_back(Filename);
+    return true;
+  }
+  return false;
 }
 
 static bool isSpecialFilename(StringRef Filename) {
   return llvm::StringSwitch<bool>(Filename)
       .Case("<built-in>", true)
       .Case("<stdin>", true)
       .Default(false);
 }
 
 bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
                                        bool IsSystem, bool IsModuleFile,
                                        bool IsMissing) {
   return !isSpecialFilename(Filename) &&
          (needSystemDependencies() || !IsSystem);
 }
 
 DependencyCollector::~DependencyCollector() { }
 void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
-  PP.addPPCallbacks(
-      llvm::make_unique<DepCollectorPPCallbacks>(*this, PP.getSourceManager()));
+  PP.addPPCallbacks(llvm::make_unique<DepCollectorPPCallbacks>(
+      *this, PP.getSourceManager(), PP.getDiagnostics()));
   PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
       llvm::make_unique<DepCollectorMMCallbacks>(*this));
 }
 void DependencyCollector::attachToASTReader(ASTReader &R) {
   R.addListener(llvm::make_unique<DepCollectorASTListener>(*this));
 }
 
-namespace {
-/// Private implementation for DependencyFileGenerator
-class DFGImpl : public PPCallbacks {
-  std::vector<std::string> Files;
-  llvm::StringSet<> FilesSet;
-  const Preprocessor *PP;
-  std::string OutputFile;
-  std::vector<std::string> Targets;
-  bool IncludeSystemHeaders;
-  bool PhonyTarget;
-  bool AddMissingHeaderDeps;
-  bool SeenMissingHeader;
-  bool IncludeModuleFiles;
-  DependencyOutputFormat OutputFormat;
-  unsigned InputFileIndex;
-
-private:
-  bool FileMatchesDepCriteria(const char *Filename,
-                              SrcMgr::CharacteristicKind FileType);
-  void OutputDependencyFile();
-
-public:
-  DFGImpl(const Preprocessor *_PP, const DependencyOutputOptions &Opts)
-    : PP(_PP), OutputFile(Opts.OutputFile), Targets(Opts.Targets),
+DependencyFileGenerator::DependencyFileGenerator(
+    const DependencyOutputOptions &Opts)
+    : OutputFile(Opts.OutputFile), Targets(Opts.Targets),
       IncludeSystemHeaders(Opts.IncludeSystemHeaders),
       PhonyTarget(Opts.UsePhonyTargets),
-      AddMissingHeaderDeps(Opts.AddMissingHeaderDeps),
-      SeenMissingHeader(false),
+      AddMissingHeaderDeps(Opts.AddMissingHeaderDeps), SeenMissingHeader(false),
       IncludeModuleFiles(Opts.IncludeModuleFiles),
-      OutputFormat(Opts.OutputFormat),
-      InputFileIndex(0) {
-    for (const auto &ExtraDep : Opts.ExtraDeps) {
-      if (AddFilename(ExtraDep))
-        ++InputFileIndex;
-    }
-  }
+      OutputFormat(Opts.OutputFormat), InputFileIndex(0) {
+    if (addDependency(ExtraDep))
 
-  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
-                   SrcMgr::CharacteristicKind FileType,
-                   FileID PrevFID) override;
-
-  void FileSkipped(const FileEntry &SkippedFile, const Token &FilenameTok,
-                   SrcMgr::CharacteristicKind FileType) override;
-
-  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
-                          StringRef FileName, bool IsAngled,
-                          CharSourceRange FilenameRange, const FileEntry *File,
-                          StringRef SearchPath, StringRef RelativePath,
-                          const Module *Imported,
-                          SrcMgr::CharacteristicKind FileType) override;
-
-  void HasInclude(SourceLocation Loc, StringRef SpelledFilename, bool IsAngled,
-                  const FileEntry *File,
-                  SrcMgr::CharacteristicKind FileType) override;
-
-  void EndOfMainFile() override {
-    OutputDependencyFile();
-  }
-
-  bool AddFilename(StringRef Filename);
-  bool includeSystemHeaders() const { return IncludeSystemHeaders; }
-  bool includeModuleFiles() const { return IncludeModuleFiles; }
-};
-
-class DFGMMCallback : public ModuleMapCallbacks {
-  DFGImpl &Parent;
-public:
-  DFGMMCallback(DFGImpl &Parent) : Parent(Parent) {}
-  void moduleMapFileRead(SourceLocation Loc, const FileEntry &Entry,
-                         bool IsSystem) override {
-    if (!IsSystem || Parent.includeSystemHeaders())
-      Parent.AddFilename(Entry.getName());
-  }
-};
-
-class DFGASTReaderListener : public ASTReaderListener {
-  DFGImpl &Parent;
-public:
-  DFGASTReaderListener(DFGImpl &Parent)
-  : Parent(Parent) { }
-  bool needsInputFileVisitation() override { return true; }
-  bool needsSystemInputFileVisitation() override {
-    return Parent.includeSystemHeaders();
-  }
-  void visitModuleFile(StringRef Filename,
-                       serialization::ModuleKind Kind) override;
-  bool visitInputFile(StringRef Filename, bool isSystem,
-                      bool isOverridden, bool isExplicitModule) override;
-};
-}
-
-DependencyFileGenerator::DependencyFileGenerator(void *Impl)
-: Impl(Impl) { }
-
-DependencyFileGenerator *DependencyFileGenerator::CreateAndAttachToPreprocessor(
-    clang::Preprocessor &PP, const clang::DependencyOutputOptions &Opts) {
-
-  if (Opts.Targets.empty()) {
+void DependencyFileGenerator::attachToPreprocessor(Preprocessor &PP) {
+  if (Targets.empty()) {
     PP.getDiagnostics().Report(diag::err_fe_dependency_file_requires_MT);
-    return nullptr;
+    return;
   }
 
   // Disable the "file not found" diagnostic if the -MG option was given.
-  if (Opts.AddMissingHeaderDeps)
+  if (AddMissingHeaderDeps)
     PP.SetSuppressIncludeNotFoundError(true);
 
-  DFGImpl *Callback = new DFGImpl(&PP, Opts);
-  PP.addPPCallbacks(std::unique_ptr<PPCallbacks>(Callback));
-  PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
-      llvm::make_unique<DFGMMCallback>(*Callback));
-  return new DependencyFileGenerator(Callback);
+  DependencyCollector::attachToPreprocessor(PP);
 }
 
-void DependencyFileGenerator::AttachToASTReader(ASTReader &R) {
-  DFGImpl *I = reinterpret_cast<DFGImpl *>(Impl);
-  assert(I && "missing implementation");
-  R.addListener(llvm::make_unique<DFGASTReaderListener>(*I));
+bool DependencyFileGenerator::sawDependency(StringRef Filename, bool FromModule,
+                                            bool IsSystem, bool IsModuleFile,
+                                            bool IsMissing) {
+  if (IsMissing) {
+    // Handle the case of missing file from an inclusion directive.
+    if (AddMissingHeaderDeps)
+      return true;
+    SeenMissingHeader = true;
+    return false;
   }
+  if (IsModuleFile && !IncludeModuleFiles)
+    return false;
 
-/// FileMatchesDepCriteria - Determine whether the given Filename should be
-/// considered as a dependency.
-bool DFGImpl::FileMatchesDepCriteria(const char *Filename,
-                                     SrcMgr::CharacteristicKind FileType) {
   if (isSpecialFilename(Filename))
     return false;
 
   if (IncludeSystemHeaders)
     return true;
 
-  return !isSystem(FileType);
-}
-
-void DFGImpl::FileChanged(SourceLocation Loc,
-                          FileChangeReason Reason,
-                          SrcMgr::CharacteristicKind FileType,
-                          FileID PrevFID) {
-  if (Reason != PPCallbacks::EnterFile)
-    return;
-
-  // Dependency generation really does want to go all the way to the
-  // file entry for a source location to find out what is depended on.
-  // We do not want #line markers to affect dependency generation!
-  SourceManager &SM = PP->getSourceManager();
-
-  const FileEntry *FE =
-    SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
-  if (!FE) return;
-
-  StringRef Filename = FE->getName();
-  if (!FileMatchesDepCriteria(Filename.data(), FileType))
-    return;
-
-  AddFilename(llvm::sys::path::remove_leading_dotslash(Filename));
+  return !IsSystem;
 }
 
-void DFGImpl::FileSkipped(const FileEntry &SkippedFile,
-                          const Token &FilenameTok,
-                          SrcMgr::CharacteristicKind FileType) {
-  StringRef Filename = SkippedFile.getName();
-  if (!FileMatchesDepCriteria(Filename.data(), FileType))
-    return;
-
-  AddFilename(llvm::sys::path::remove_leading_dotslash(Filename));
-}
-
-void DFGImpl::InclusionDirective(SourceLocation HashLoc,
-                                 const Token &IncludeTok,
-                                 StringRef FileName,
-                                 bool IsAngled,
-                                 CharSourceRange FilenameRange,
-                                 const FileEntry *File,
-                                 StringRef SearchPath,
-                                 StringRef RelativePath,
-                                 const Module *Imported,
-                                 SrcMgr::CharacteristicKind FileType) {
-  if (!File) {
-    if (AddMissingHeaderDeps)
-      AddFilename(FileName);
-    else
-      SeenMissingHeader = true;
-  }
-}
-
-void DFGImpl::HasInclude(SourceLocation Loc, StringRef SpelledFilename,
-                         bool IsAngled, const FileEntry *File,
-                         SrcMgr::CharacteristicKind FileType) {
-  if (!File)
-    return;
-  StringRef Filename = File->getName();
-  if (!FileMatchesDepCriteria(Filename.data(), FileType))
-    return;
-  AddFilename(llvm::sys::path::remove_leading_dotslash(Filename));
-}
-
-bool DFGImpl::AddFilename(StringRef Filename) {
-  if (FilesSet.insert(Filename).second) {
-    Files.push_back(Filename);
-    return true;
-  }
-  return false;
+void DependencyFileGenerator::finishedMainFile(DiagnosticsEngine &Diags) {
+  outputDependencyFile(Diags);
 }
 
 /// Print the filename, with escaping or quoting that accommodates the three
 /// most likely tools that use dependency files: GNU Make, BSD Make, and
 /// NMake/Jom.
 ///
 /// BSD Make is the simplest case: It does no escaping at all.  This means
 /// characters that are normally delimiters, i.e. space and # (the comment
else if (NativePath[i] == ' ') { // Handle space correctly.
       while (j > 0 && NativePath[--j] == '\\')
         OS << '\\';
     } else if (NativePath[i] == '$') // $ is escaped by $$.
       OS << '$';
     OS << NativePath[i];
   }
 }
 
-void DFGImpl::OutputDependencyFile() {
+void DependencyFileGenerator::outputDependencyFile(DiagnosticsEngine &Diags) {
   if (SeenMissingHeader) {
     llvm::sys::fs::remove(OutputFile);
     return;
   }
 
   std::error_code EC;
   llvm::raw_fd_ostream OS(OutputFile, EC, llvm::sys::fs::F_Text);
   if (EC) {
-    PP->getDiagnostics().Report(diag::err_fe_error_opening) << OutputFile
-                                                            << EC.message();
+    Diags.Report(diag::err_fe_error_opening) << OutputFile << EC.message();
     return;
   }
 
   // Write out the dependency targets, trying to avoid overly long
   // lines when possible. We try our best to emit exactly the same
   // dependency file as GCC (4.2), assuming the included files are the
   // same.
   const unsigned MaxColumns = 75;
for (StringRef Target : Targets) {
     OS << Target;
   }
 
   OS << ':';
   Columns += 1;
 
   // Now add each dependency in the order it was seen, but avoiding
   // duplicates.
+  ArrayRef<std::string> Files = getDependencies();
   for (StringRef File : Files) {
     // Start a new line if this would exceed the column limit. Make
     // sure to leave space for a trailing " \" in case we need to
     // break the line on the next iteration.
     unsigned N = File.size();
     if (Columns + (N + 1) + 2 > MaxColumns) {
       OS << " \\\n ";
       Columns = 2;
for (auto I = Files.begin(), E = Files.end(); I != E; ++I) {
       if (Index++ == InputFileIndex)
         continue;
       OS << '\n';
       PrintFilename(OS, *I, OutputFormat);
       OS << ":\n";
     }
   }
 }
-
-bool DFGASTReaderListener::visitInputFile(llvm::StringRef Filename,
-                                          bool IsSystem, bool IsOverridden,
-                                          bool IsExplicitModule) {
-  assert(!IsSystem || needsSystemInputFileVisitation());
-  if (IsOverridden || IsExplicitModule)
-    return true;
-
-  Parent.AddFilename(Filename);
-  return true;
-}
-
-void DFGASTReaderListener::visitModuleFile(llvm::StringRef Filename,
-                                           serialization::ModuleKind Kind) {
-  if (Parent.includeModuleFiles())
-    Parent.AddFilename(Filename);
-}