[clang][AST][NFC] Factor out check for structural equivalence of names.

We have four places that we try to decide which name to use for the
test for structural equivalence, and in each of those we evaluate
getTypedefNameForAnonDecl twice. Pull out the check into a function to
reduce duplication and evaluate things only once.

Differential Revision: https://reviews.llvm.org/D149981

diff --git a/clang/lib/AST/ASTStructuralEquivalence.cpp b/clang/lib/AST/ASTStructuralEquivalence.cpp
index ba7dfc35edf21c37535824a32d25561284803263..a9470782c634e11835d9988b8ebf47deba3397e7 100644 (file)
--- a/clang/lib/AST/ASTStructuralEquivalence.cpp
+++ b/clang/lib/AST/ASTStructuralEquivalence.cpp
@@ -1453,19 +1453,23 @@ static bool IsRecordContextStructurallyEquivalent(RecordDecl *D1,
   return true;
 }
 
+static bool NameIsStructurallyEquivalent(const TagDecl &D1, const TagDecl &D2) {
+  auto GetName = [](const TagDecl &D) -> const IdentifierInfo * {
+    if (const IdentifierInfo *Name = D.getIdentifier())
+      return Name;
+    if (const TypedefNameDecl *TypedefName = D.getTypedefNameForAnonDecl())
+      return TypedefName->getIdentifier();
+    return nullptr;
+  };
+  return IsStructurallyEquivalent(GetName(D1), GetName(D2));
+}
+
 /// Determine structural equivalence of two records.
 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
                                      RecordDecl *D1, RecordDecl *D2) {
-
-  // Check for equivalent structure names.
-  IdentifierInfo *Name1 = D1->getIdentifier();
-  if (!Name1 && D1->getTypedefNameForAnonDecl())
-    Name1 = D1->getTypedefNameForAnonDecl()->getIdentifier();
-  IdentifierInfo *Name2 = D2->getIdentifier();
-  if (!Name2 && D2->getTypedefNameForAnonDecl())
-    Name2 = D2->getTypedefNameForAnonDecl()->getIdentifier();
-  if (!IsStructurallyEquivalent(Name1, Name2))
+  if (!NameIsStructurallyEquivalent(*D1, *D2)) {
     return false;
+  }
 
   if (D1->isUnion() != D2->isUnion()) {
     if (Context.Complain) {
@@ -1727,16 +1731,9 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
 /// Determine structural equivalence of two enums.
 static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context,
                                      EnumDecl *D1, EnumDecl *D2) {
-
-  // Check for equivalent enum names.
-  IdentifierInfo *Name1 = D1->getIdentifier();
-  if (!Name1 && D1->getTypedefNameForAnonDecl())
-    Name1 = D1->getTypedefNameForAnonDecl()->getIdentifier();
-  IdentifierInfo *Name2 = D2->getIdentifier();
-  if (!Name2 && D2->getTypedefNameForAnonDecl())
-    Name2 = D2->getTypedefNameForAnonDecl()->getIdentifier();
-  if (!IsStructurallyEquivalent(Name1, Name2))
+  if (!NameIsStructurallyEquivalent(*D1, *D2)) {
     return false;
+  }
 
   // Compare the definitions of these two enums. If either or both are
   // incomplete (i.e. forward declared), we assume that they are equivalent.