[MS ABI] Correctly mangle classes without names for linkage purposes

A class without a name for linkage purposes gets a name along the lines
of <unnamed-type-foo> where foo is either the name of a declarator which
defined it (like a variable or field) or a
typedef-name (like a typedef or alias-declaration).

We handled the declarator case correctly but it would fall down during
template instantiation if the declarator didn't share the tag's type.
We failed to handle the typedef-name case at all.

Instead, keep track of the association between the two and keep it up to
date in the face of template instantiation.

llvm-svn: 246469

2 files changed, 3 insertions, 11 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 00785aa1d05..25a684a531e 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -441,8 +441,8 @@ void ASTDeclReader::Visit(Decl *D) {
     // If this is a tag declaration with a typedef name for linkage, it's safe
     // to load that typedef now.
     if (NamedDeclForTagDecl)
-      cast<TagDecl>(D)->NamedDeclOrQualifier =
-          cast<NamedDecl>(Reader.GetDecl(NamedDeclForTagDecl));
+      cast<TagDecl>(D)->TypedefNameDeclOrQualifier =
+          cast<TypedefNameDecl>(Reader.GetDecl(NamedDeclForTagDecl));
   } else if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
     // if we have a fully initialized TypeDecl, we can safely read its type now.
     ID->TypeForDecl = Reader.GetType(TypeIDForTypeDecl).getTypePtrOrNull();
@@ -595,16 +595,13 @@ ASTDeclReader::RedeclarableResult ASTDeclReader::VisitTagDecl(TagDecl *TD) {
   case 1: { // ExtInfo
     TagDecl::ExtInfo *Info = new (Reader.getContext()) TagDecl::ExtInfo();
     ReadQualifierInfo(*Info, Record, Idx);
-    TD->NamedDeclOrQualifier = Info;
+    TD->TypedefNameDeclOrQualifier = Info;
     break;
   }
   case 2: // TypedefNameForAnonDecl
     NamedDeclForTagDecl = ReadDeclID(Record, Idx);
     TypedefNameForLinkage = Reader.GetIdentifierInfo(F, Record, Idx);
     break;
-  case 3: // DeclaratorForAnonDecl
-    NamedDeclForTagDecl = ReadDeclID(Record, Idx);
-    break;
   default:
     llvm_unreachable("unexpected tag info kind");
   }
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index d38e58766a2..24e07c42a41 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -378,9 +378,6 @@ void ASTDeclWriter::VisitTagDecl(TagDecl *D) {
     Record.push_back(2);
     Writer.AddDeclRef(TD, Record);
     Writer.AddIdentifierRef(TD->getDeclName().getAsIdentifierInfo(), Record);
-  } else if (auto *DD = D->getDeclaratorForAnonDecl()) {
-    Record.push_back(3);
-    Writer.AddDeclRef(DD, Record);
   } else {
     Record.push_back(0);
   }
@@ -410,7 +407,6 @@ void ASTDeclWriter::VisitEnumDecl(EnumDecl *D) {
       !D->isUsed(false) &&
       !D->hasExtInfo() &&
       !D->getTypedefNameForAnonDecl() &&
-      !D->getDeclaratorForAnonDecl() &&
       D->getFirstDecl() == D->getMostRecentDecl() &&
       !D->isInvalidDecl() &&
       !D->isReferenced() &&
@@ -439,7 +435,6 @@ void ASTDeclWriter::VisitRecordDecl(RecordDecl *D) {
       !D->isUsed(false) &&
       !D->hasExtInfo() &&
       !D->getTypedefNameForAnonDecl() &&
-      !D->getDeclaratorForAnonDecl() &&
       D->getFirstDecl() == D->getMostRecentDecl() &&
       !D->isInvalidDecl() &&
       !D->isReferenced() &&