llvm/unittests/Transforms/Utils/ValueMapperTest.cpp - rust-lang/llvm-project - Git at Google

 //===- ValueMapper.cpp - Unit tests for ValueMapper -----------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/Transforms/Utils/ValueMapper.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Metadata.h"
 #include "gtest/gtest.h"

 using namespace llvm;

 namespace {

 TEST(ValueMapperTest, mapMDNode) {
   LLVMContext Context;
   auto *U = MDTuple::get(Context, None);

   // The node should be unchanged.
   ValueToValueMapTy VM;
   EXPECT_EQ(U, ValueMapper(VM).mapMDNode(*U));
 }

 TEST(ValueMapperTest, mapMDNodeCycle) {
   LLVMContext Context;
   MDNode *U0;
   MDNode *U1;
   {
     Metadata *Ops[] = {nullptr};
     auto T = MDTuple::getTemporary(Context, Ops);
     Ops[0] = T.get();
     U0 = MDTuple::get(Context, Ops);
     T->replaceOperandWith(0, U0);
     U1 = MDNode::replaceWithUniqued(std::move(T));
     U0->resolveCycles();
   }

   EXPECT_TRUE(U0->isResolved());
   EXPECT_TRUE(U0->isUniqued());
   EXPECT_TRUE(U1->isResolved());
   EXPECT_TRUE(U1->isUniqued());
   EXPECT_EQ(U1, U0->getOperand(0));
   EXPECT_EQ(U0, U1->getOperand(0));

   // Cycles shouldn't be duplicated.
   {
     ValueToValueMapTy VM;
     EXPECT_EQ(U0, ValueMapper(VM).mapMDNode(*U0));
     EXPECT_EQ(U1, ValueMapper(VM).mapMDNode(*U1));
   }

   // Check the other order.
   {
     ValueToValueMapTy VM;
     EXPECT_EQ(U1, ValueMapper(VM).mapMDNode(*U1));
     EXPECT_EQ(U0, ValueMapper(VM).mapMDNode(*U0));
   }
 }

 TEST(ValueMapperTest, mapMDNodeDuplicatedCycle) {
   LLVMContext Context;
   auto *PtrTy = Type::getInt8Ty(Context)->getPointerTo();
   std::unique_ptr<GlobalVariable> G0 = std::make_unique<GlobalVariable>(
       PtrTy, false, GlobalValue::ExternalLinkage, nullptr, "G0");
   std::unique_ptr<GlobalVariable> G1 = std::make_unique<GlobalVariable>(
       PtrTy, false, GlobalValue::ExternalLinkage, nullptr, "G1");

   // Create a cycle that references G0.
   MDNode *N0; // !0 = !{!1}
   MDNode *N1; // !1 = !{!0, i8* @G0}
   {
     auto T0 = MDTuple::getTemporary(Context, nullptr);
     Metadata *Ops1[] = {T0.get(), ConstantAsMetadata::get(G0.get())};
     N1 = MDTuple::get(Context, Ops1);
     T0->replaceOperandWith(0, N1);
     N0 = MDNode::replaceWithUniqued(std::move(T0));
   }

   // Resolve N0 and N1.
   ASSERT_FALSE(N0->isResolved());
   ASSERT_FALSE(N1->isResolved());
   N0->resolveCycles();
   ASSERT_TRUE(N0->isResolved());
   ASSERT_TRUE(N1->isResolved());

   // Seed the value map to map G0 to G1 and map the nodes.  The output should
   // have new nodes that reference G1 (instead of G0).
   ValueToValueMapTy VM;
   VM[G0.get()] = G1.get();
   MDNode *MappedN0 = ValueMapper(VM).mapMDNode(*N0);
   MDNode *MappedN1 = ValueMapper(VM).mapMDNode(*N1);
   EXPECT_NE(N0, MappedN0);
   EXPECT_NE(N1, MappedN1);
   EXPECT_EQ(ConstantAsMetadata::get(G1.get()), MappedN1->getOperand(1));

   // Check that the output nodes are resolved.
   EXPECT_TRUE(MappedN0->isResolved());
   EXPECT_TRUE(MappedN1->isResolved());
 }

 TEST(ValueMapperTest, mapMDNodeUnresolved) {
   LLVMContext Context;
   TempMDTuple T = MDTuple::getTemporary(Context, None);

   ValueToValueMapTy VM;
   EXPECT_EQ(T.get(), ValueMapper(VM, RF_NoModuleLevelChanges).mapMDNode(*T));
 }

 TEST(ValueMapperTest, mapMDNodeDistinct) {
   LLVMContext Context;
   auto *D = MDTuple::getDistinct(Context, None);

   {
     // The node should be cloned.
     ValueToValueMapTy VM;
     EXPECT_NE(D, ValueMapper(VM).mapMDNode(*D));
   }
   {
     // The node should be moved.
     ValueToValueMapTy VM;
     EXPECT_EQ(D, ValueMapper(VM, RF_MoveDistinctMDs).mapMDNode(*D));
   }
 }

 TEST(ValueMapperTest, mapMDNodeDistinctOperands) {
   LLVMContext Context;
   Metadata *Old = MDTuple::getDistinct(Context, None);
   auto *D = MDTuple::getDistinct(Context, Old);
   ASSERT_EQ(Old, D->getOperand(0));

   Metadata *New = MDTuple::getDistinct(Context, None);
   ValueToValueMapTy VM;
   VM.MD()[Old].reset(New);

   // Make sure operands are updated.
   EXPECT_EQ(D, ValueMapper(VM, RF_MoveDistinctMDs).mapMDNode(*D));
   EXPECT_EQ(New, D->getOperand(0));
 }

 TEST(ValueMapperTest, mapMDNodeSeeded) {
   LLVMContext Context;
   auto *D = MDTuple::getDistinct(Context, None);

   // The node should be moved.
   ValueToValueMapTy VM;
   EXPECT_EQ(None, VM.getMappedMD(D));

   VM.MD().insert(std::make_pair(D, TrackingMDRef(D)));
   EXPECT_EQ(D, *VM.getMappedMD(D));
   EXPECT_EQ(D, ValueMapper(VM).mapMDNode(*D));
 }

 TEST(ValueMapperTest, mapMDNodeSeededWithNull) {
   LLVMContext Context;
   auto *D = MDTuple::getDistinct(Context, None);

   // The node should be moved.
   ValueToValueMapTy VM;
   EXPECT_EQ(None, VM.getMappedMD(D));

   VM.MD().insert(std::make_pair(D, TrackingMDRef()));
   EXPECT_EQ(nullptr, *VM.getMappedMD(D));
   EXPECT_EQ(nullptr, ValueMapper(VM).mapMDNode(*D));
 }

 TEST(ValueMapperTest, mapMetadataNullMapGlobalWithIgnoreMissingLocals) {
   LLVMContext C;
   FunctionType *FTy =
       FunctionType::get(Type::getVoidTy(C), Type::getInt8Ty(C), false);
   std::unique_ptr<Function> F(
       Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));

   ValueToValueMapTy VM;
   RemapFlags Flags = RF_IgnoreMissingLocals | RF_NullMapMissingGlobalValues;
   EXPECT_EQ(nullptr, ValueMapper(VM, Flags).mapValue(*F));
 }

 TEST(ValueMapperTest, mapMetadataMDString) {
   LLVMContext C;
   auto *S1 = MDString::get(C, "S1");
   ValueToValueMapTy VM;

   // Make sure S1 maps to itself, but isn't memoized.
   EXPECT_EQ(S1, ValueMapper(VM).mapMetadata(*S1));
   EXPECT_EQ(None, VM.getMappedMD(S1));

   // We still expect VM.MD() to be respected.
   auto *S2 = MDString::get(C, "S2");
   VM.MD()[S1].reset(S2);
   EXPECT_EQ(S2, ValueMapper(VM).mapMetadata(*S1));
 }

 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, ValueMapper(VM).mapMetadata(*N0));
   EXPECT_EQ(N1, ValueMapper(VM).mapMetadata(*N1));
   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, ValueMapper(VM, RF_NoModuleLevelChanges).mapMetadata(*N0));
   EXPECT_EQ(N1, ValueMapper(VM, RF_NoModuleLevelChanges).mapMetadata(*N1));
   EXPECT_FALSE(VM.hasMD());
   EXPECT_EQ(None, VM.getMappedMD(N0));
   EXPECT_EQ(None, VM.getMappedMD(N1));
 }

 TEST(ValueMapperTest, mapMetadataConstantAsMetadata) {
   LLVMContext C;
   FunctionType *FTy =
       FunctionType::get(Type::getVoidTy(C), Type::getInt8Ty(C), false);
   std::unique_ptr<Function> F(
       Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));

   auto *CAM = ConstantAsMetadata::get(F.get());
   {
     // ConstantAsMetadata shouldn't be memoized.
     ValueToValueMapTy VM;
     EXPECT_EQ(CAM, ValueMapper(VM).mapMetadata(*CAM));
     EXPECT_FALSE(VM.MD().count(CAM));
     EXPECT_EQ(CAM, ValueMapper(VM, RF_IgnoreMissingLocals).mapMetadata(*CAM));
     EXPECT_FALSE(VM.MD().count(CAM));

     // But it should respect a mapping that gets seeded.
     auto *N = MDTuple::get(C, None);
     VM.MD()[CAM].reset(N);
     EXPECT_EQ(N, ValueMapper(VM).mapMetadata(*CAM));
     EXPECT_EQ(N, ValueMapper(VM, RF_IgnoreMissingLocals).mapMetadata(*CAM));
   }

   std::unique_ptr<Function> F2(
       Function::Create(FTy, GlobalValue::ExternalLinkage, "F2"));
   ValueToValueMapTy VM;
   VM[F.get()] = F2.get();
   auto *F2MD = ValueMapper(VM).mapMetadata(*CAM);
   EXPECT_FALSE(VM.MD().count(CAM));
   EXPECT_TRUE(F2MD);
   EXPECT_EQ(F2.get(), cast<ConstantAsMetadata>(F2MD)->getValue());
 }

 #ifdef GTEST_HAS_DEATH_TEST
 #ifndef NDEBUG
 TEST(ValueMapperTest, mapMetadataLocalAsMetadata) {
   LLVMContext C;
   FunctionType *FTy =
       FunctionType::get(Type::getVoidTy(C), Type::getInt8Ty(C), false);
   std::unique_ptr<Function> F(
       Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));
   Argument &A = *F->arg_begin();

   // mapMetadata doesn't support LocalAsMetadata.  The only valid container for
   // LocalAsMetadata is a MetadataAsValue instance, so use it directly.
   auto *LAM = LocalAsMetadata::get(&A);
   ValueToValueMapTy VM;
   EXPECT_DEATH(ValueMapper(VM).mapMetadata(*LAM), "Unexpected local metadata");
   EXPECT_DEATH(ValueMapper(VM, RF_IgnoreMissingLocals).mapMetadata(*LAM),
                "Unexpected local metadata");
 }
 #endif
 #endif

 TEST(ValueMapperTest, mapValueLocalAsMetadata) {
   LLVMContext C;
   FunctionType *FTy =
       FunctionType::get(Type::getVoidTy(C), Type::getInt8Ty(C), false);
   std::unique_ptr<Function> F(
       Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));
   Argument &A = *F->arg_begin();

   auto *LAM = LocalAsMetadata::get(&A);
   auto *MAV = MetadataAsValue::get(C, LAM);

   // The principled answer to a LocalAsMetadata of an unmapped SSA value would
   // be to return nullptr (regardless of RF_IgnoreMissingLocals).
   //
   // However, algorithms that use RemapInstruction assume that each instruction
   // only references SSA values from previous instructions.  Arguments of
   // such as "metadata i32 %x" don't currently successfully maintain that
   // property.  To keep RemapInstruction from crashing we need a non-null
   // return here, but we also shouldn't reference the unmapped local.  Use
   // "metadata !{}".
   auto *N0 = MDTuple::get(C, None);
   auto *N0AV = MetadataAsValue::get(C, N0);
   ValueToValueMapTy VM;
   EXPECT_EQ(N0AV, ValueMapper(VM).mapValue(*MAV));
   EXPECT_EQ(nullptr, ValueMapper(VM, RF_IgnoreMissingLocals).mapValue(*MAV));
   EXPECT_FALSE(VM.count(MAV));
   EXPECT_FALSE(VM.count(&A));
   EXPECT_EQ(None, VM.getMappedMD(LAM));

   VM[MAV] = MAV;
   EXPECT_EQ(MAV, ValueMapper(VM).mapValue(*MAV));
   EXPECT_EQ(MAV, ValueMapper(VM, RF_IgnoreMissingLocals).mapValue(*MAV));
   EXPECT_TRUE(VM.count(MAV));
   EXPECT_FALSE(VM.count(&A));

   VM[MAV] = &A;
   EXPECT_EQ(&A, ValueMapper(VM).mapValue(*MAV));
   EXPECT_EQ(&A, ValueMapper(VM, RF_IgnoreMissingLocals).mapValue(*MAV));
   EXPECT_TRUE(VM.count(MAV));
   EXPECT_FALSE(VM.count(&A));
 }

 TEST(ValueMapperTest, mapValueLocalAsMetadataToConstant) {
   LLVMContext Context;
   auto *Int8 = Type::getInt8Ty(Context);
   FunctionType *FTy = FunctionType::get(Type::getVoidTy(Context), Int8, false);
   std::unique_ptr<Function> F(
       Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));

   // Map a local value to a constant.
   Argument &A = *F->arg_begin();
   Constant &C = *ConstantInt::get(Int8, 42);
   ValueToValueMapTy VM;
   VM[&A] = &C;

   // Look up the metadata-as-value wrapper.  Don't crash.
   auto *MDA = MetadataAsValue::get(Context, ValueAsMetadata::get(&A));
   auto *MDC = MetadataAsValue::get(Context, ValueAsMetadata::get(&C));
   EXPECT_TRUE(isa<LocalAsMetadata>(MDA->getMetadata()));
   EXPECT_TRUE(isa<ConstantAsMetadata>(MDC->getMetadata()));
   EXPECT_EQ(&C, ValueMapper(VM).mapValue(A));
   EXPECT_EQ(MDC, ValueMapper(VM).mapValue(*MDA));
 }

 } // end namespace
	//===- ValueMapper.cpp - Unit tests for ValueMapper -----------------------===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/Transforms/Utils/ValueMapper.h"
	#include "llvm/IR/Constants.h"
	#include "llvm/IR/Function.h"
	#include "llvm/IR/GlobalVariable.h"
	#include "llvm/IR/LLVMContext.h"
	#include "llvm/IR/Metadata.h"
	#include "gtest/gtest.h"

	using namespace llvm;

	namespace {

	TEST(ValueMapperTest, mapMDNode) {
	LLVMContext Context;
	auto *U = MDTuple::get(Context, None);

	// The node should be unchanged.
	ValueToValueMapTy VM;
	EXPECT_EQ(U, ValueMapper(VM).mapMDNode(*U));
	}

	TEST(ValueMapperTest, mapMDNodeCycle) {
	LLVMContext Context;
	MDNode *U0;
	MDNode *U1;
	{
	Metadata *Ops[] = {nullptr};
	auto T = MDTuple::getTemporary(Context, Ops);
	Ops[0] = T.get();
	U0 = MDTuple::get(Context, Ops);
	T->replaceOperandWith(0, U0);
	U1 = MDNode::replaceWithUniqued(std::move(T));
	U0->resolveCycles();
	}

	EXPECT_TRUE(U0->isResolved());
	EXPECT_TRUE(U0->isUniqued());
	EXPECT_TRUE(U1->isResolved());
	EXPECT_TRUE(U1->isUniqued());
	EXPECT_EQ(U1, U0->getOperand(0));
	EXPECT_EQ(U0, U1->getOperand(0));

	// Cycles shouldn't be duplicated.
	{
	ValueToValueMapTy VM;
	EXPECT_EQ(U0, ValueMapper(VM).mapMDNode(*U0));
	EXPECT_EQ(U1, ValueMapper(VM).mapMDNode(*U1));
	}

	// Check the other order.
	{
	ValueToValueMapTy VM;
	EXPECT_EQ(U1, ValueMapper(VM).mapMDNode(*U1));
	EXPECT_EQ(U0, ValueMapper(VM).mapMDNode(*U0));
	}
	}

	TEST(ValueMapperTest, mapMDNodeDuplicatedCycle) {
	LLVMContext Context;
	auto *PtrTy = Type::getInt8Ty(Context)->getPointerTo();
	std::unique_ptr<GlobalVariable> G0 = std::make_unique<GlobalVariable>(
	PtrTy, false, GlobalValue::ExternalLinkage, nullptr, "G0");
	std::unique_ptr<GlobalVariable> G1 = std::make_unique<GlobalVariable>(
	PtrTy, false, GlobalValue::ExternalLinkage, nullptr, "G1");

	// Create a cycle that references G0.
	MDNode *N0; // !0 = !{!1}
	MDNode N1; // !1 = !{!0, i8 @G0}
	{
	auto T0 = MDTuple::getTemporary(Context, nullptr);
	Metadata *Ops1[] = {T0.get(), ConstantAsMetadata::get(G0.get())};
	N1 = MDTuple::get(Context, Ops1);
	T0->replaceOperandWith(0, N1);
	N0 = MDNode::replaceWithUniqued(std::move(T0));
	}

	// Resolve N0 and N1.
	ASSERT_FALSE(N0->isResolved());
	ASSERT_FALSE(N1->isResolved());
	N0->resolveCycles();
	ASSERT_TRUE(N0->isResolved());
	ASSERT_TRUE(N1->isResolved());

	// Seed the value map to map G0 to G1 and map the nodes. The output should
	// have new nodes that reference G1 (instead of G0).
	ValueToValueMapTy VM;
	VM[G0.get()] = G1.get();
	MDNode MappedN0 = ValueMapper(VM).mapMDNode(N0);
	MDNode MappedN1 = ValueMapper(VM).mapMDNode(N1);
	EXPECT_NE(N0, MappedN0);
	EXPECT_NE(N1, MappedN1);
	EXPECT_EQ(ConstantAsMetadata::get(G1.get()), MappedN1->getOperand(1));

	// Check that the output nodes are resolved.
	EXPECT_TRUE(MappedN0->isResolved());
	EXPECT_TRUE(MappedN1->isResolved());
	}

	TEST(ValueMapperTest, mapMDNodeUnresolved) {
	LLVMContext Context;
	TempMDTuple T = MDTuple::getTemporary(Context, None);

	ValueToValueMapTy VM;
	EXPECT_EQ(T.get(), ValueMapper(VM, RF_NoModuleLevelChanges).mapMDNode(*T));
	}

	TEST(ValueMapperTest, mapMDNodeDistinct) {
	LLVMContext Context;
	auto *D = MDTuple::getDistinct(Context, None);

	{
	// The node should be cloned.
	ValueToValueMapTy VM;
	EXPECT_NE(D, ValueMapper(VM).mapMDNode(*D));
	}
	{
	// The node should be moved.
	ValueToValueMapTy VM;
	EXPECT_EQ(D, ValueMapper(VM, RF_MoveDistinctMDs).mapMDNode(*D));
	}
	}

	TEST(ValueMapperTest, mapMDNodeDistinctOperands) {
	LLVMContext Context;
	Metadata *Old = MDTuple::getDistinct(Context, None);
	auto *D = MDTuple::getDistinct(Context, Old);
	ASSERT_EQ(Old, D->getOperand(0));

	Metadata *New = MDTuple::getDistinct(Context, None);
	ValueToValueMapTy VM;
	VM.MD()[Old].reset(New);

	// Make sure operands are updated.
	EXPECT_EQ(D, ValueMapper(VM, RF_MoveDistinctMDs).mapMDNode(*D));
	EXPECT_EQ(New, D->getOperand(0));
	}

	TEST(ValueMapperTest, mapMDNodeSeeded) {
	LLVMContext Context;
	auto *D = MDTuple::getDistinct(Context, None);

	// The node should be moved.
	ValueToValueMapTy VM;
	EXPECT_EQ(None, VM.getMappedMD(D));

	VM.MD().insert(std::make_pair(D, TrackingMDRef(D)));
	EXPECT_EQ(D, *VM.getMappedMD(D));
	EXPECT_EQ(D, ValueMapper(VM).mapMDNode(*D));
	}

	TEST(ValueMapperTest, mapMDNodeSeededWithNull) {
	LLVMContext Context;
	auto *D = MDTuple::getDistinct(Context, None);

	// The node should be moved.
	ValueToValueMapTy VM;
	EXPECT_EQ(None, VM.getMappedMD(D));

	VM.MD().insert(std::make_pair(D, TrackingMDRef()));
	EXPECT_EQ(nullptr, *VM.getMappedMD(D));
	EXPECT_EQ(nullptr, ValueMapper(VM).mapMDNode(*D));
	}

	TEST(ValueMapperTest, mapMetadataNullMapGlobalWithIgnoreMissingLocals) {
	LLVMContext C;
	FunctionType *FTy =
	FunctionType::get(Type::getVoidTy(C), Type::getInt8Ty(C), false);
	std::unique_ptr<Function> F(
	Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));

	ValueToValueMapTy VM;
	RemapFlags Flags = RF_IgnoreMissingLocals \| RF_NullMapMissingGlobalValues;
	EXPECT_EQ(nullptr, ValueMapper(VM, Flags).mapValue(*F));
	}

	TEST(ValueMapperTest, mapMetadataMDString) {
	LLVMContext C;
	auto *S1 = MDString::get(C, "S1");
	ValueToValueMapTy VM;

	// Make sure S1 maps to itself, but isn't memoized.
	EXPECT_EQ(S1, ValueMapper(VM).mapMetadata(*S1));
	EXPECT_EQ(None, VM.getMappedMD(S1));

	// We still expect VM.MD() to be respected.
	auto *S2 = MDString::get(C, "S2");
	VM.MD()[S1].reset(S2);
	EXPECT_EQ(S2, ValueMapper(VM).mapMetadata(*S1));
	}

	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, ValueMapper(VM).mapMetadata(*N0));
	EXPECT_EQ(N1, ValueMapper(VM).mapMetadata(*N1));
	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, ValueMapper(VM, RF_NoModuleLevelChanges).mapMetadata(*N0));
	EXPECT_EQ(N1, ValueMapper(VM, RF_NoModuleLevelChanges).mapMetadata(*N1));
	EXPECT_FALSE(VM.hasMD());
	EXPECT_EQ(None, VM.getMappedMD(N0));
	EXPECT_EQ(None, VM.getMappedMD(N1));
	}

	TEST(ValueMapperTest, mapMetadataConstantAsMetadata) {
	LLVMContext C;
	FunctionType *FTy =
	FunctionType::get(Type::getVoidTy(C), Type::getInt8Ty(C), false);
	std::unique_ptr<Function> F(
	Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));

	auto *CAM = ConstantAsMetadata::get(F.get());
	{
	// ConstantAsMetadata shouldn't be memoized.
	ValueToValueMapTy VM;
	EXPECT_EQ(CAM, ValueMapper(VM).mapMetadata(*CAM));
	EXPECT_FALSE(VM.MD().count(CAM));
	EXPECT_EQ(CAM, ValueMapper(VM, RF_IgnoreMissingLocals).mapMetadata(*CAM));
	EXPECT_FALSE(VM.MD().count(CAM));

	// But it should respect a mapping that gets seeded.
	auto *N = MDTuple::get(C, None);
	VM.MD()[CAM].reset(N);
	EXPECT_EQ(N, ValueMapper(VM).mapMetadata(*CAM));
	EXPECT_EQ(N, ValueMapper(VM, RF_IgnoreMissingLocals).mapMetadata(*CAM));
	}

	std::unique_ptr<Function> F2(
	Function::Create(FTy, GlobalValue::ExternalLinkage, "F2"));
	ValueToValueMapTy VM;
	VM[F.get()] = F2.get();
	auto F2MD = ValueMapper(VM).mapMetadata(CAM);
	EXPECT_FALSE(VM.MD().count(CAM));
	EXPECT_TRUE(F2MD);
	EXPECT_EQ(F2.get(), cast<ConstantAsMetadata>(F2MD)->getValue());
	}

	#ifdef GTEST_HAS_DEATH_TEST
	#ifndef NDEBUG
	TEST(ValueMapperTest, mapMetadataLocalAsMetadata) {
	LLVMContext C;
	FunctionType *FTy =
	FunctionType::get(Type::getVoidTy(C), Type::getInt8Ty(C), false);
	std::unique_ptr<Function> F(
	Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));
	Argument &A = *F->arg_begin();

	// mapMetadata doesn't support LocalAsMetadata. The only valid container for
	// LocalAsMetadata is a MetadataAsValue instance, so use it directly.
	auto *LAM = LocalAsMetadata::get(&A);
	ValueToValueMapTy VM;
	EXPECT_DEATH(ValueMapper(VM).mapMetadata(*LAM), "Unexpected local metadata");
	EXPECT_DEATH(ValueMapper(VM, RF_IgnoreMissingLocals).mapMetadata(*LAM),
	"Unexpected local metadata");
	}
	#endif
	#endif

	TEST(ValueMapperTest, mapValueLocalAsMetadata) {
	LLVMContext C;
	FunctionType *FTy =
	FunctionType::get(Type::getVoidTy(C), Type::getInt8Ty(C), false);
	std::unique_ptr<Function> F(
	Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));
	Argument &A = *F->arg_begin();

	auto *LAM = LocalAsMetadata::get(&A);
	auto *MAV = MetadataAsValue::get(C, LAM);

	// The principled answer to a LocalAsMetadata of an unmapped SSA value would
	// be to return nullptr (regardless of RF_IgnoreMissingLocals).
	//
	// However, algorithms that use RemapInstruction assume that each instruction
	// only references SSA values from previous instructions. Arguments of
	// such as "metadata i32 %x" don't currently successfully maintain that
	// property. To keep RemapInstruction from crashing we need a non-null
	// return here, but we also shouldn't reference the unmapped local. Use
	// "metadata !{}".
	auto *N0 = MDTuple::get(C, None);
	auto *N0AV = MetadataAsValue::get(C, N0);
	ValueToValueMapTy VM;
	EXPECT_EQ(N0AV, ValueMapper(VM).mapValue(*MAV));
	EXPECT_EQ(nullptr, ValueMapper(VM, RF_IgnoreMissingLocals).mapValue(*MAV));
	EXPECT_FALSE(VM.count(MAV));
	EXPECT_FALSE(VM.count(&A));
	EXPECT_EQ(None, VM.getMappedMD(LAM));

	VM[MAV] = MAV;
	EXPECT_EQ(MAV, ValueMapper(VM).mapValue(*MAV));
	EXPECT_EQ(MAV, ValueMapper(VM, RF_IgnoreMissingLocals).mapValue(*MAV));
	EXPECT_TRUE(VM.count(MAV));
	EXPECT_FALSE(VM.count(&A));

	VM[MAV] = &A;
	EXPECT_EQ(&A, ValueMapper(VM).mapValue(*MAV));
	EXPECT_EQ(&A, ValueMapper(VM, RF_IgnoreMissingLocals).mapValue(*MAV));
	EXPECT_TRUE(VM.count(MAV));
	EXPECT_FALSE(VM.count(&A));
	}

	TEST(ValueMapperTest, mapValueLocalAsMetadataToConstant) {
	LLVMContext Context;
	auto *Int8 = Type::getInt8Ty(Context);
	FunctionType *FTy = FunctionType::get(Type::getVoidTy(Context), Int8, false);
	std::unique_ptr<Function> F(
	Function::Create(FTy, GlobalValue::ExternalLinkage, "F"));

	// Map a local value to a constant.
	Argument &A = *F->arg_begin();
	Constant &C = *ConstantInt::get(Int8, 42);
	ValueToValueMapTy VM;
	VM[&A] = &C;

	// Look up the metadata-as-value wrapper. Don't crash.
	auto *MDA = MetadataAsValue::get(Context, ValueAsMetadata::get(&A));
	auto *MDC = MetadataAsValue::get(Context, ValueAsMetadata::get(&C));
	EXPECT_TRUE(isa<LocalAsMetadata>(MDA->getMetadata()));
	EXPECT_TRUE(isa<ConstantAsMetadata>(MDC->getMetadata()));
	EXPECT_EQ(&C, ValueMapper(VM).mapValue(A));
	EXPECT_EQ(MDC, ValueMapper(VM).mapValue(*MDA));
	}

	} // end namespace