[CTU] Refactor threshold checking

[gamesh411]

Incremental change

[gamesh411]

Incremental change

[gamesh411]

Incremental change

[gamesh411]

Incremental change

[gamesh411]

Incremental change

clang/include/clang/CrossTU/CrossTranslationUnit.h

public:
   static std::string getLookupName(const NamedDecl *ND);
 
   /// Emit diagnostics for the user for potential configuration errors.
   void emitCrossTUDiagnostics(const IndexError &IE);
 
 private:
   bool checkThresholdReached() const;
   llvm::Error lazyInitCTUIndex(StringRef CrossTUDir, StringRef IndexName);
+  ASTUnit *getCachedASTUnitForName(StringRef LookupName) const;
   void lazyInitImporterSharedSt(TranslationUnitDecl *ToTU);
   ASTImporter &getOrCreateASTImporter(ASTContext &From);
   template <typename T>
   llvm::Expected<const T *> getCrossTUDefinitionImpl(const T *D,
                                                      StringRef CrossTUDir,
                                                      StringRef IndexName,
                                                      bool DisplayCTUProgress);
   template <typename T>

clang/lib/CrossTU/CrossTranslationUnit.cpp

if (auto IndexMapping = parseCrossTUIndex(IndexFile, CrossTUDir)) {
     NameFileMap = *IndexMapping;
     return llvm::Error::success();
   } else {
     // Error while parsing CrossTU index file.
     return IndexMapping.takeError();
   };
 }
 
+ASTUnit *CrossTranslationUnitContext::getCachedASTUnitForName(
+    StringRef LookupName) const {
+  auto CacheEntry = NameASTUnitMap.find(LookupName);
+  if (CacheEntry != NameASTUnitMap.end())
+    return CacheEntry->second;
+  else
+    return nullptr;
+}
+
 llvm::Expected<ASTUnit *> CrossTranslationUnitContext::loadExternalAST(
     StringRef LookupName, StringRef CrossTUDir, StringRef IndexName,
     bool DisplayCTUProgress) {
   // FIXME: The current implementation only supports loading decls with
   //        a lookup name from a single translation unit. If multiple
   //        translation units contains decls with the same lookup name an
   //        error will be returned.
 
   // If import threshold is reached, don't import anything.
   if (checkThresholdReached())
     return llvm::make_error<IndexError>(
         index_error_code::load_threshold_reached);
 
-  ASTUnit *Unit = nullptr;
-  auto NameUnitCacheEntry = NameASTUnitMap.find(LookupName);
-  if (NameUnitCacheEntry == NameASTUnitMap.end()) {
-    // Lazily initialize the mapping from function names to AST files.
-    if (llvm::Error InitFailed = lazyInitCTUIndex(CrossTUDir, IndexName))
-      return std::move(InitFailed);
+  // First try to access the cache to get the ASTUnit for the function name
+  // specified by LookupName.
+  ASTUnit *Unit = getCachedASTUnitForName(LookupName);
+  if (Unit)
+    return Unit;
+
 
-    auto It = NameFileMap.find(LookupName);
-    if (It == NameFileMap.end()) {
-      ++NumNotInOtherTU;
-      return llvm::make_error<IndexError>(index_error_code::missing_definition);
-    }
-    StringRef ASTFileName = It->second;
-    auto ASTCacheEntry = FileASTUnitMap.find(ASTFileName);
-    if (ASTCacheEntry == FileASTUnitMap.end()) {
-      IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
-      TextDiagnosticPrinter *DiagClient =
-          new TextDiagnosticPrinter(llvm::errs(), &*DiagOpts);
-      IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
-      IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
-          new DiagnosticsEngine(DiagID, &*DiagOpts, DiagClient));
 
-      std::unique_ptr<ASTUnit> LoadedUnit(ASTUnit::LoadFromASTFile(
-          ASTFileName, CI.getPCHContainerOperations()->getRawReader(),
-          ASTUnit::LoadEverything, Diags, CI.getFileSystemOpts()));
-      Unit = LoadedUnit.get();
-      FileASTUnitMap[ASTFileName] = std::move(LoadedUnit);
-      ++NumASTLoaded;
-      if (DisplayCTUProgress) {
-        llvm::errs() << "CTU loaded AST file: "
-                     << ASTFileName << "\n";
-      }
-    } else {
-      Unit = ASTCacheEntry->second.get();
-    }
-    NameASTUnitMap[LookupName] = Unit;
-  } else {
-    Unit = NameUnitCacheEntry->second;
-  }
+      llvm::errs() << "CTU loaded AST file: " << ASTFileName << "\n";
+
   if (!Unit)
     return llvm::make_error<IndexError>(
         index_error_code::failed_to_get_external_ast);
   return Unit;
 }
 
 template <typename T>
 llvm::Expected<const T *>