fix PR10384: C++ allows external arrays of incomplete type as well.

Many thanks to Eli for reducing this great testcase.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135752 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/CodeGen/CodeGenTypes.cpp b/lib/CodeGen/CodeGenTypes.cpp
index ee629ec9b0..87b3da5000 100644
--- a/lib/CodeGen/CodeGenTypes.cpp
+++ b/lib/CodeGen/CodeGenTypes.cpp
@@ -419,6 +419,14 @@ llvm::Type *CodeGenTypes::ConvertType(QualType T) {
   case Type::ConstantArray: {
     const ConstantArrayType *A = cast<ConstantArrayType>(Ty);
     llvm::Type *EltTy = ConvertTypeForMem(A->getElementType());
+    
+    // Lower arrays of undefined struct type to arrays of i8 just to have a 
+    // concrete type.
+    if (!EltTy->isSized()) {
+      SkippedLayout = true;
+      EltTy = llvm::Type::getInt8Ty(getLLVMContext());
+    }
+
     ResultType = llvm::ArrayType::get(EltTy, A->getSize().getZExtValue());
     break;
   }