ValueMapper: Don't memoize metadata when RF_NoModuleLevelChanges

Prevent the Metadata side-table in ValueMap from growing unnecessarily
when RF_NoModuleLevelChanges.  As a drive-by, make ValueMap::hasMD,
which apparently had no users until I used it here for testing, actually
compile.

llvm-svn: 265828

1 files changed, 32 insertions, 0 deletions

diff --git a/llvm/unittests/Transforms/Utils/ValueMapperTest.cpp b/llvm/unittests/Transforms/Utils/ValueMapperTest.cpp
index 3bccd503c1b..5221ab705a3 100644
--- a/llvm/unittests/Transforms/Utils/ValueMapperTest.cpp
+++ b/llvm/unittests/Transforms/Utils/ValueMapperTest.cpp
@@ -155,6 +155,38 @@ TEST(ValueMapperTest, MapMetadataMDString) {
   EXPECT_EQ(S2, MapMetadata(S1, VM));
 }
 
+TEST(ValueMapperTest, MapMetadataGetMappedMD) {
+  LLVMContext C;
+  auto *N0 = MDTuple::get(C, None);
+  auto *N1 = MDTuple::get(C, N0);
+
+  // Make sure hasMD and getMappedMD work correctly.
+  ValueToValueMapTy VM;
+  EXPECT_FALSE(VM.hasMD());
+  EXPECT_EQ(N0, MapMetadata(N0, VM));
+  EXPECT_EQ(N1, MapMetadata(N1, VM));
+  EXPECT_TRUE(VM.hasMD());
+  ASSERT_NE(None, VM.getMappedMD(N0));
+  ASSERT_NE(None, VM.getMappedMD(N1));
+  EXPECT_EQ(N0, *VM.getMappedMD(N0));
+  EXPECT_EQ(N1, *VM.getMappedMD(N1));
+}
+
+TEST(ValueMapperTest, MapMetadataNoModuleLevelChanges) {
+  LLVMContext C;
+  auto *N0 = MDTuple::get(C, None);
+  auto *N1 = MDTuple::get(C, N0);
+
+  // Nothing should be memoized when RF_NoModuleLevelChanges.
+  ValueToValueMapTy VM;
+  EXPECT_FALSE(VM.hasMD());
+  EXPECT_EQ(N0, MapMetadata(N0, VM, RF_NoModuleLevelChanges));
+  EXPECT_EQ(N1, MapMetadata(N1, VM, RF_NoModuleLevelChanges));
+  EXPECT_FALSE(VM.hasMD());
+  EXPECT_EQ(None, VM.getMappedMD(N0));
+  EXPECT_EQ(None, VM.getMappedMD(N1));
+}
+
 TEST(ValueMapperTest, MapMetadataConstantAsMetadata) {
   LLVMContext C;
   FunctionType *FTy =