DebugInfo: Support type alias templates

We already got the type alias correct (though I've included a test case
here) since Clang represents that like any other typedef - but type
alias templates weren't being handled.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205691 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGDebugInfo.cpp

@@ -719,6 +719,32 @@ llvm::DIType CGDebugInfo::CreateType(const BlockPointerType *Ty,
   return BlockLiteralGeneric;
 }
 
+llvm::DIType CGDebugInfo::CreateType(const TemplateSpecializationType *Ty, llvm::DIFile Unit) {
+  assert(Ty->isTypeAlias());
+  llvm::DIType Src = getOrCreateType(Ty->getAliasedType(), Unit);
+  assert(Src);
+
+  SmallString<128> NS;
+  llvm::raw_svector_ostream OS(NS);
+  Ty->getTemplateName().print(OS, CGM.getContext().getPrintingPolicy(), /*qualified*/ false);
+
+  TemplateSpecializationType::PrintTemplateArgumentList(
+      OS, Ty->getArgs(), Ty->getNumArgs(),
+      CGM.getContext().getPrintingPolicy());
+
+  TypeAliasDecl *AliasDecl =
+      cast<TypeAliasTemplateDecl>(Ty->getTemplateName().getAsTemplateDecl())
+          ->getTemplatedDecl();
+
+  SourceLocation Loc = AliasDecl->getLocation();
+  llvm::DIFile File = getOrCreateFile(Loc);
+  unsigned Line = getLineNumber(Loc);
+
+  llvm::DIDescriptor Ctxt = getContextDescriptor(cast<Decl>(AliasDecl->getDeclContext()));
+
+  return DBuilder.createTypedef(Src, internString(OS.str()), File, Line, Ctxt);
+}
+
 llvm::DIType CGDebugInfo::CreateType(const TypedefType *Ty, llvm::DIFile Unit) {
   // Typedefs are derived from some other type.  If we have a typedef of a
   // typedef, make sure to emit the whole chain.
@@ -1932,9 +1958,12 @@ static QualType UnwrapTypeForDebugInfo(QualType T, const ASTContext &C) {
     switch (T->getTypeClass()) {
     default:
       return C.getQualifiedType(T.getTypePtr(), Quals);
-    case Type::TemplateSpecialization:
-      T = cast<TemplateSpecializationType>(T)->desugar();
-      break;
+    case Type::TemplateSpecialization: {
+      const auto *Spec = cast<TemplateSpecializationType>(T);
+      if (Spec->isTypeAlias())
+        return C.getQualifiedType(T.getTypePtr(), Quals);
+      T = Spec->desugar();
+      break; }
     case Type::TypeOfExpr:
       T = cast<TypeOfExprType>(T)->getUnderlyingExpr()->getType();
       break;
@@ -2191,8 +2220,10 @@ llvm::DIType CGDebugInfo::CreateTypeNode(QualType Ty, llvm::DIFile Unit) {
   case Type::Atomic:
     return CreateType(cast<AtomicType>(Ty), Unit);
 
-  case Type::Attributed:
   case Type::TemplateSpecialization:
+    return CreateType(cast<TemplateSpecializationType>(Ty), Unit);
+
+  case Type::Attributed:
   case Type::Elaborated:
   case Type::Paren:
   case Type::SubstTemplateTypeParm:

lib/CodeGen/CGDebugInfo.h

@@ -109,6 +109,7 @@ class CGDebugInfo {
   llvm::DIType CreateType(const ComplexType *Ty);
   llvm::DIType CreateQualifiedType(QualType Ty, llvm::DIFile Fg);
   llvm::DIType CreateType(const TypedefType *Ty, llvm::DIFile Fg);
+  llvm::DIType CreateType(const TemplateSpecializationType *Ty, llvm::DIFile Fg);
   llvm::DIType CreateType(const ObjCObjectPointerType *Ty,
                           llvm::DIFile F);
   llvm::DIType CreateType(const PointerType *Ty, llvm::DIFile F);

test/CodeGenCXX/debug-info-alias.cpp

@@ -0,0 +1,28 @@
+// RUN: %clang -g -std=c++11 -S -emit-llvm %s -o - | FileCheck %s
+
+template<typename T>
+struct foo {
+};
+namespace x {
+// splitting these over multiple lines to make sure the right token is used for
+// the location
+template<typename T>
+using
+# 42
+bar
+= foo<T*>;
+}
+
+// CHECK: metadata [[BINT:![0-9]*]], i32 0, i32 1, {{.*}} ; [ DW_TAG_variable ] [bi]
+// CHECK: [[BINT]] = {{.*}} ; [ DW_TAG_typedef ] [bar<int>] [line 42
+x::bar<int> bi;
+// CHECK: metadata [[BFLOAT:![0-9]*]], i32 0, i32 1, {{.*}} ; [ DW_TAG_variable ] [bf]
+// CHECK: [[BFLOAT]] = {{.*}} ; [ DW_TAG_typedef ] [bar<float>] [line 42
+x::bar<float> bf;
+
+using
+// metadata [[NARF:![0-9]*]], i32 0, i32 1, {{.*}} ; [ DW_TAG_variable ] [n]
+narf // [[NARF]] = {{.*}} ; [ DW_TAG_typedef ] [narf] [line [[@LINE]]
+= int;
+narf n;
+