Replace map with set

Author: dmpolukhin

clang/include/clang/Serialization/ASTReader.h

@@ -1392,19 +1392,8 @@ class ASTReader
 
   llvm::DenseMap<const Decl *, bool> DefinitionSource;
 
-  /// The set of extra flags about declarations that we have read from
-  /// the module file.
-  struct ExternalDeclarationBits {
-    /// Indicates if given function declaration was a definition but its body
-    /// was removed due to declaration merging.
-    bool ThisDeclarationWasADefinition : 1;
-
-    ExternalDeclarationBits() : ThisDeclarationWasADefinition(false) {}
-  };
-
-  /// A mapping from declarations to extra bits of information about this decl.
-  llvm::DenseMap<const Decl *, ExternalDeclarationBits>
-      ExternalDeclarationBitsMap;
+  /// Friend functions that were defined but might have had their bodies removed.
+  llvm::DenseSet<const FunctionDecl *> ThisDeclarationWasADefinitionSet;
 
   bool shouldDisableValidationForFile(const serialization::ModuleFile &M) const;
 

clang/lib/Serialization/ASTReader.cpp

@@ -9661,10 +9661,7 @@ ExternalASTSource::ExtKind ASTReader::hasExternalDefinitions(const Decl *FD) {
 }
 
 bool ASTReader::wasThisDeclarationADefinition(const FunctionDecl *FD) {
-  auto I = ExternalDeclarationBitsMap.find(FD);
-  if (I == ExternalDeclarationBitsMap.end())
-    return false;
-  return I->second.ThisDeclarationWasADefinition;
+  return ThisDeclarationWasADefinitionSet.contains(FD);
 }
 
 Selector ASTReader::getLocalSelector(ModuleFile &M, unsigned LocalID) {

clang/lib/Serialization/ASTReaderDecl.cpp

@@ -525,7 +525,7 @@ void ASTDeclReader::ReadFunctionDefinition(FunctionDecl *FD) {
   Reader.PendingBodies[FD] = GetCurrentCursorOffset();
   // For now remember ThisDeclarationWasADefinition only for friend functions.
   if (FD->getFriendObjectKind())
-    Reader.ExternalDeclarationBitsMap[FD].ThisDeclarationWasADefinition = true;
+    Reader.ThisDeclarationWasADefinitionSet.insert(FD);
 }
 
 void ASTDeclReader::Visit(Decl *D) {