IR: Add missing null operand to MDSubroutineType

Add missing `nullptr` from `MDSubroutineType`'s operands for
`MDCompositeTypeBase::getIdentifier()` (and add tests for all the other
unused fields).  This highlights just how crazy it is that
`MDSubroutineType` inherits from `MDCompositeTypeBase`.

llvm-svn: 229926

2 files changed, 10 insertions, 1 deletions

diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index ab79a713357..a2f5d55c3c6 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -200,7 +200,7 @@ MDSubroutineType *MDSubroutineType::getImpl(LLVMContext &Context,
                                             bool ShouldCreate) {
   DEFINE_GETIMPL_LOOKUP(MDSubroutineType, (Flags, TypeArray));
   Metadata *Ops[] = {nullptr,   nullptr, nullptr, nullptr,
-                     TypeArray, nullptr, nullptr};
+                     TypeArray, nullptr, nullptr, nullptr};
   DEFINE_GETIMPL_STORE(MDSubroutineType, (Flags), Ops);
 }
 
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index ea49880e918..0c1ef82205e 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -964,6 +964,15 @@ TEST_F(MDSubroutineTypeTest, get) {
 
   TempMDSubroutineType Temp = N->clone();
   EXPECT_EQ(N, MDNode::replaceWithUniqued(std::move(Temp)));
+
+  // Test always-empty operands.
+  EXPECT_EQ(nullptr, N->getScope());
+  EXPECT_EQ(nullptr, N->getFile());
+  EXPECT_EQ("", N->getName());
+  EXPECT_EQ(nullptr, N->getBaseType());
+  EXPECT_EQ(nullptr, N->getVTableHolder());
+  EXPECT_EQ(nullptr, N->getTemplateParams());
+  EXPECT_EQ("", N->getIdentifier());
 }
 
 typedef MetadataTest MDFileTest;