[clang][deps] NFC: Don't collect PCH input files

Since b4c83a1, PCH input files are no longer necessary.

(cherry picked from commit 34f1439)

Author: jansvoboda11

clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp

@@ -74,27 +74,18 @@ class PrebuiltModuleListener : public ASTReaderListener {
 public:
   PrebuiltModuleListener(CompilerInstance &CI,
                          PrebuiltModuleFilesT &PrebuiltModuleFiles,
-                         llvm::StringSet<> &InputFiles, bool VisitInputFiles,
                          llvm::SmallVector<std::string> &NewModuleFiles)
       : CI(CI), PrebuiltModuleFiles(PrebuiltModuleFiles),
-        InputFiles(InputFiles), VisitInputFiles(VisitInputFiles),
+
         NewModuleFiles(NewModuleFiles) {}
 
   bool needsImportVisitation() const override { return true; }
-  bool needsInputFileVisitation() override { return VisitInputFiles; }
-  bool needsSystemInputFileVisitation() override { return VisitInputFiles; }
 
   void visitImport(StringRef ModuleName, StringRef Filename) override {
     if (PrebuiltModuleFiles.insert({ModuleName.str(), Filename.str()}).second)
       NewModuleFiles.push_back(Filename.str());
   }
 
-  bool visitInputFile(StringRef Filename, bool isSystem, bool isOverridden,
-                      bool isExplicitModule) override {
-    InputFiles.insert(Filename);
-    return true;
-  }
-
   bool readModuleCacheKey(StringRef ModuleName, StringRef Filename,
                           StringRef CacheKey) override {
     CI.getFrontendOpts().ModuleCacheKeys.emplace_back(std::string(Filename),
@@ -106,22 +97,17 @@ class PrebuiltModuleListener : public ASTReaderListener {
 private:
   CompilerInstance &CI;
   PrebuiltModuleFilesT &PrebuiltModuleFiles;
-  llvm::StringSet<> &InputFiles;
-  bool VisitInputFiles;
   llvm::SmallVector<std::string> &NewModuleFiles;
 };
 
 /// Visit the given prebuilt module and collect all of the modules it
 /// transitively imports and contributing input files.
 static void visitPrebuiltModule(StringRef PrebuiltModuleFilename,
                                 CompilerInstance &CI,
-                                PrebuiltModuleFilesT &ModuleFiles,
-                                llvm::StringSet<> &InputFiles,
-                                bool VisitInputFiles) {
+                                PrebuiltModuleFilesT &ModuleFiles) {
   // List of module files to be processed.
   llvm::SmallVector<std::string> Worklist{PrebuiltModuleFilename.str()};
-  PrebuiltModuleListener Listener(CI, ModuleFiles, InputFiles, VisitInputFiles,
-                                  Worklist);
+  PrebuiltModuleListener Listener(CI, ModuleFiles, Worklist);
 
   while (!Worklist.empty())
     ASTReader::readASTFileControlBlock(
@@ -375,16 +361,13 @@ class DependencyScanningAction : public tooling::ToolAction {
 
     ScanInstance.createSourceManager(*FileMgr);
 
-    llvm::StringSet<> PrebuiltModulesInputFiles;
     // Store the list of prebuilt module files into header search options. This
     // will prevent the implicit build to create duplicate modules and will
     // force reuse of the existing prebuilt module files instead.
     if (!ScanInstance.getPreprocessorOpts().ImplicitPCHInclude.empty())
       visitPrebuiltModule(
           ScanInstance.getPreprocessorOpts().ImplicitPCHInclude, ScanInstance,
-          ScanInstance.getHeaderSearchOpts().PrebuiltModuleFiles,
-          PrebuiltModulesInputFiles,
-          /*VisitInputFiles=*/getDepScanFS() != nullptr);
+          ScanInstance.getHeaderSearchOpts().PrebuiltModuleFiles);
 
     // Use the dependency scanning optimized file system if requested to do so.
     if (DepFS) {