MSVC ABI: Support C++11's auto on variables

The MSVC C++ ABI always uses the deduced type in place of auto when
generating external names for variables.

N.B.  MSVC doesn't support C++1y's 'operator auto' and this patch will
not give us said functionality.

llvm-svn: 199764
diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index 30c53ed0..ece1204 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -345,7 +345,7 @@
   // Pointers and references are odd. The type of 'int * const foo;' gets
   // mangled as 'QAHA' instead of 'PAHB', for example.
   TypeLoc TL = VD->getTypeSourceInfo()->getTypeLoc();
-  QualType Ty = TL.getType();
+  QualType Ty = VD->getType();
   if (Ty->isPointerType() || Ty->isReferenceType() ||
       Ty->isMemberPointerType()) {
     mangleType(Ty, TL.getSourceRange(), QMM_Drop);
@@ -1803,6 +1803,8 @@
 }
 
 void MicrosoftCXXNameMangler::mangleType(const AutoType *T, SourceRange Range) {
+  assert(T->getDeducedType().isNull() && "expecting a dependent type!");
+
   DiagnosticsEngine &Diags = Context.getDiags();
   unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
     "cannot mangle this 'auto' type yet");
diff --git a/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp b/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp
index c3e7370..fd59ae6 100644
--- a/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp
+++ b/clang/test/CodeGenCXX/mangle-ms-cxx11.cpp
@@ -1,5 +1,8 @@
 // RUN: %clang_cc1 -std=c++11 -fms-extensions -emit-llvm %s -o - -triple=i386-pc-win32 | FileCheck %s
 
+// CHECK: "\01?DeducedType@@3HA"
+auto DeducedType = 30;
+
 // CHECK: "\01?LRef@@YAXAAH@Z"
 void LRef(int& a) { }