3 files changed, 19 insertions, 0 deletions
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 248698f45a..140687f425 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -607,6 +607,9 @@ void ASTContext::InitBuiltinTypes(const TargetInfo &Target) {
 
   // half type (OpenCL 6.1.1.1) / ARM NEON __fp16
   InitBuiltinType(HalfTy, BuiltinType::Half);
+
+  // Builtin type used to help define __builtin_va_list.
+  VaListTagTy = QualType();
 }
 
 DiagnosticsEngine &ASTContext::getDiagnostics() const {
@@ -5115,6 +5118,7 @@ static TypedefDecl *CreatePowerABIBuiltinVaListDecl(const ASTContext *Context) {
   }
   VaListTagDecl->completeDefinition();
   QualType VaListTagType = Context->getRecordType(VaListTagDecl);
+  Context->VaListTagTy = VaListTagType;
 
   // } __va_list_tag;
   TypedefDecl *VaListTagTypedefDecl
@@ -5188,6 +5192,7 @@ CreateX86_64ABIBuiltinVaListDecl(const ASTContext *Context) {
   }
   VaListTagDecl->completeDefinition();
   QualType VaListTagType = Context->getRecordType(VaListTagDecl);
+  Context->VaListTagTy = VaListTagType;
 
   // } __va_list_tag;
   TypedefDecl *VaListTagTypedefDecl
@@ -5257,6 +5262,15 @@ TypedefDecl *ASTContext::getBuiltinVaListDecl() const {
   return BuiltinVaListDecl;
 }
 
+QualType ASTContext::getVaListTagType() const {
+  // Force the creation of VaListTagTy by building the __builtin_va_list
+  // declaration.
+  if (VaListTagTy.isNull())
+    (void) getBuiltinVaListDecl();
+
+  return VaListTagTy;
+}
+
 void ASTContext::setObjCConstantStringInterface(ObjCInterfaceDecl *Decl) {
   assert(ObjCConstantStringType.isNull() &&
          "'NSConstantString' type already set!");
diff --git a/lib/Serialization/ASTCommon.h b/lib/Serialization/ASTCommon.h
index 16db8e3695..eacb39d86e 100644
--- a/lib/Serialization/ASTCommon.h
+++ b/lib/Serialization/ASTCommon.h
@@ -50,6 +50,8 @@ TypeID MakeTypeID(ASTContext &Context, QualType T, IdxForTypeTy IdxForType) {
     return TypeIdx(PREDEF_TYPE_AUTO_DEDUCT).asTypeID(FastQuals);
   if (T == Context.AutoRRefDeductTy)
     return TypeIdx(PREDEF_TYPE_AUTO_RREF_DEDUCT).asTypeID(FastQuals);
+  if (T == Context.VaListTagTy)
+    return TypeIdx(PREDEF_TYPE_VA_LIST_TAG).asTypeID(FastQuals);
 
   return IdxForType(T).asTypeID(FastQuals);
 }
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 8b354f3557..b118685b9b 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -4461,6 +4461,9 @@ QualType ASTReader::GetType(TypeID ID) {
       T = Context.ARCUnbridgedCastTy;
       break;
 
+    case PREDEF_TYPE_VA_LIST_TAG:
+      T = Context.getVaListTagType();
+      break;
     }
 
     assert(!T.isNull() && "Unknown predefined type");