[MS ABI] Mangle static anonymous unions

We believed that internal linkage variables at global scope which are
not variable template specializations did not have to be mangled.

However, static anonymous unions have no identifier and therefore must
be mangled.

This fixes PR18204.

llvm-svn: 250997

3 files changed, 13 insertions, 13 deletions

diff --git a/clang/lib/AST/MicrosoftCXXABI.cpp b/clang/lib/AST/MicrosoftCXXABI.cpp
index ff84fa5c225..6ba31ccf1e3 100644
--- a/clang/lib/AST/MicrosoftCXXABI.cpp
+++ b/clang/lib/AST/MicrosoftCXXABI.cpp
@@ -89,17 +89,7 @@ public:
   }
 
   bool isNearlyEmpty(const CXXRecordDecl *RD) const override {
-    // FIXME: Audit the corners
-    if (!RD->isDynamicClass())
-      return false;
-
-    const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
-
-    // In the Microsoft ABI, classes can have one or two vtable pointers.
-    CharUnits PointerSize =
-        Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
-    return Layout.getNonVirtualSize() == PointerSize ||
-      Layout.getNonVirtualSize() == PointerSize * 2;
+    llvm_unreachable("unapplicable to the MS ABI");
   }
 
   void addDefaultArgExprForConstructor(const CXXConstructorDecl *CD,
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index c4baed21cb4..5c30ae28b34 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -365,7 +365,8 @@ bool MicrosoftMangleContextImpl::shouldMangleCXXName(const NamedDecl *D) {
         DC = getEffectiveParentContext(DC);
 
     if (DC->isTranslationUnit() && D->getFormalLinkage() == InternalLinkage &&
-        !isa<VarTemplateSpecializationDecl>(D))
+        !isa<VarTemplateSpecializationDecl>(D) &&
+        D->getIdentifier() != nullptr)
       return false;
   }
 
@@ -801,7 +802,7 @@ void MicrosoftCXXNameMangler::mangleUnqualifiedName(const NamedDecl *ND,
       } else {
         // Otherwise, number the types using a $S prefix.
         Name += "$S";
-        Name += llvm::utostr(Context.getAnonymousStructId(TD));
+        Name += llvm::utostr(Context.getAnonymousStructId(TD) + 1);
       }
       Name += ">";
       mangleSourceName(Name.str());
diff --git a/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp b/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp
index 0a4c602df62..999def87fc5 100644
--- a/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp
+++ b/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp
@@ -277,3 +277,12 @@ void g() {
 // CHECK-DAG: @"\01??$f@W4<unnamed-type-E>@?1??g@PR24651@@YAXXZ@@PR24651@@YAXW4<unnamed-type-E>@?1??g@0@YAXXZ@@Z"
 // CHECK-DAG: @"\01??$f@W4<unnamed-type-E>@?2??g@PR24651@@YAXXZ@@PR24651@@YAXW4<unnamed-type-E>@?2??g@0@YAXXZ@@Z"
 }
+
+namespace PR18204 {
+template <typename T>
+int f(T *);
+static union {
+  int n = f(this);
+};
+// CHECK-DAG: @"\01??$f@T<unnamed-type-$S1>@PR18204@@@PR18204@@YAHPAT<unnamed-type-$S1>@0@@Z"
+}