4 files changed, 36 insertions, 4 deletions
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 577dd0adaf2..80ce66a0174 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -7508,6 +7508,23 @@ size_t ASTContext::getSideTableAllocatedMemory() const {
     + llvm::capacity_in_bytes(ClassScopeSpecializationPattern);
 }
 
+void ASTContext::addUnnamedTag(const TagDecl *Tag) {
+  // FIXME: This mangling should be applied to function local classes too
+  if (!Tag->getName().empty() || Tag->getTypedefNameForAnonDecl() ||
+      !isa<CXXRecordDecl>(Tag->getParent()) || Tag->getLinkage() != ExternalLinkage)
+    return;
+
+  std::pair<llvm::DenseMap<const DeclContext *, unsigned>::iterator, bool> P =
+    UnnamedMangleContexts.insert(std::make_pair(Tag->getParent(), 0));
+  UnnamedMangleNumbers.insert(std::make_pair(Tag, P.first->second++));
+}
+
+int ASTContext::getUnnamedTagManglingNumber(const TagDecl *Tag) const {
+  llvm::DenseMap<const TagDecl *, unsigned>::const_iterator I =
+    UnnamedMangleNumbers.find(Tag);
+  return I != UnnamedMangleNumbers.end() ? I->second : -1;
+}
+
 unsigned ASTContext::getLambdaManglingNumber(CXXMethodDecl *CallOperator) {
   CXXRecordDecl *Lambda = CallOperator->getParent();
   return LambdaMangleContexts[Lambda->getDeclContext()]
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 74abbaa492d..9569841a568 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -480,8 +480,7 @@ static LinkageInfo getLVForClassMember(const NamedDecl *D, bool OnlyTemplate) {
   if (!(isa<CXXMethodDecl>(D) ||
         isa<VarDecl>(D) ||
         isa<FieldDecl>(D) ||
-        (isa<TagDecl>(D) &&
-         (D->getDeclName() || cast<TagDecl>(D)->getTypedefNameForAnonDecl()))))
+        isa<TagDecl>(D)))
     return LinkageInfo::none();
 
   LinkageInfo LV;
@@ -2561,8 +2560,7 @@ void TagDecl::setTypedefNameForAnonDecl(TypedefNameDecl *TDD) {
 void TagDecl::startDefinition() {
   IsBeingDefined = true;
 
-  if (isa<CXXRecordDecl>(this)) {
-    CXXRecordDecl *D = cast<CXXRecordDecl>(this);
+  if (CXXRecordDecl *D = dyn_cast<CXXRecordDecl>(this)) {
     struct CXXRecordDecl::DefinitionData *Data = 
       new (getASTContext()) struct CXXRecordDecl::DefinitionData(D);
     for (redecl_iterator I = redecls_begin(), E = redecls_end(); I != E; ++I)
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 851944a42b6..fc61d88bd9f 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -1117,6 +1117,18 @@ void CXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
         break;
       }
     }
+
+    int UnnamedMangle = Context.getASTContext().getUnnamedTagManglingNumber(TD);
+    if (UnnamedMangle != -1) {
+      Out << "Ut";
+      if (UnnamedMangle != 0)
+        Out << llvm::utostr(UnnamedMangle - 1);
+      Out << '_';
+      break;
+    }
+
+    //assert(cast<RecordDecl>(RD)->isAnonymousStructOrUnion() && "Don't mangle unnamed things as "
+    //  "anonymous things");
         
     // Get a unique id for the anonymous struct.
     uint64_t AnonStructId = Context.getAnonymousStructId(TD);
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 04f66e5882b..72516fda80c 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -2655,6 +2655,7 @@ Decl *Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS,
   }
 
   if (Tag) {
+    getASTContext().addUnnamedTag(Tag);
     Tag->setFreeStanding();
     if (Tag->isInvalidDecl())
       return Tag;
@@ -7355,6 +7356,10 @@ Sema::FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
     if (Decl *D = Group[i])
       Decls.push_back(D);
 
+  if (DeclSpec::isDeclRep(DS.getTypeSpecType()))
+    if (const TagDecl *Tag = dyn_cast_or_null<TagDecl>(DS.getRepAsDecl()))
+      getASTContext().addUnnamedTag(Tag);
+
   return BuildDeclaratorGroup(Decls.data(), Decls.size(),
                               DS.getTypeSpecType() == DeclSpec::TST_auto);
 }