+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
+ return VM[V] = CE->getWithOperands(Ops, NewTy);
+ if (isa<ConstantArray>(C))
+ return VM[V] = ConstantArray::get(cast<ArrayType>(NewTy), Ops);
+ if (isa<ConstantStruct>(C))
+ return VM[V] = ConstantStruct::get(cast<StructType>(NewTy), Ops);
+ if (isa<ConstantVector>(C))
+ return VM[V] = ConstantVector::get(Ops);
+ // If this is a no-operand constant, it must be because the type was remapped.
+ if (isa<UndefValue>(C))
+ return VM[V] = UndefValue::get(NewTy);
+ if (isa<ConstantAggregateZero>(C))
+ return VM[V] = ConstantAggregateZero::get(NewTy);
+ assert(isa<ConstantPointerNull>(C));
+ return VM[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
+}
+
+static Metadata *mapToMetadata(ValueToValueMapTy &VM, const Metadata *Key,
+ Metadata *Val) {
+ VM.MD()[Key].reset(Val);
+ return Val;
+}
+
+static Metadata *mapToSelf(ValueToValueMapTy &VM, const Metadata *MD) {
+ return mapToMetadata(VM, MD, const_cast<Metadata *>(MD));
+}
+
+static Metadata *MapMetadataImpl(const Metadata *MD,
+ SmallVectorImpl<MDNode *> &Cycles,
+ ValueToValueMapTy &VM, RemapFlags Flags,
+ ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer);
+
+static Metadata *mapMetadataOp(Metadata *Op, SmallVectorImpl<MDNode *> &Cycles,
+ ValueToValueMapTy &VM, RemapFlags Flags,
+ ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
+ if (!Op)
+ return nullptr;
+ if (Metadata *MappedOp =
+ MapMetadataImpl(Op, Cycles, VM, Flags, TypeMapper, Materializer))
+ return MappedOp;
+ // Use identity map if MappedOp is null and we can ignore missing entries.
+ if (Flags & RF_IgnoreMissingEntries)
+ return Op;
+
+ // FIXME: This assert crashes during bootstrap, but I think it should be
+ // correct. For now, just match behaviour from before the metadata/value
+ // split.
+ //
+ // llvm_unreachable("Referenced metadata not in value map!");
+ return nullptr;
+}
+
+/// \brief Remap nodes.
+///
+/// Insert \c NewNode in the value map, and then remap \c OldNode's operands.
+/// Assumes that \c NewNode is already a clone of \c OldNode.
+///
+/// \pre \c NewNode is a clone of \c OldNode.
+static bool remap(const MDNode *OldNode, MDNode *NewNode,
+ SmallVectorImpl<MDNode *> &Cycles, ValueToValueMapTy &VM,
+ RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
+ assert(OldNode->getNumOperands() == NewNode->getNumOperands() &&
+ "Expected nodes to match");
+ assert(OldNode->isResolved() && "Expected resolved node");
+ assert(!NewNode->isUniqued() && "Expected non-uniqued node");
+
+ // Map the node upfront so it's available for cyclic references.
+ mapToMetadata(VM, OldNode, NewNode);
+ bool AnyChanged = false;
+ for (unsigned I = 0, E = OldNode->getNumOperands(); I != E; ++I) {
+ Metadata *Old = OldNode->getOperand(I);
+ assert(NewNode->getOperand(I) == Old &&
+ "Expected old operands to already be in place");
+
+ Metadata *New = mapMetadataOp(OldNode->getOperand(I), Cycles, VM, Flags,
+ TypeMapper, Materializer);
+ if (Old != New) {
+ AnyChanged = true;
+ NewNode->replaceOperandWith(I, New);
+ }
+ }
+
+ return AnyChanged;
+}
+
+/// \brief Map a distinct MDNode.
+///
+/// Distinct nodes are not uniqued, so they must always recreated.
+static Metadata *mapDistinctNode(const MDNode *Node,
+ SmallVectorImpl<MDNode *> &Cycles,
+ ValueToValueMapTy &VM, RemapFlags Flags,
+ ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
+ assert(Node->isDistinct() && "Expected distinct node");
+
+ MDNode *NewMD = MDNode::replaceWithDistinct(Node->clone());
+ remap(Node, NewMD, Cycles, VM, Flags, TypeMapper, Materializer);
+
+ // Track any cycles beneath this node.
+ for (Metadata *Op : NewMD->operands())
+ if (auto *Node = dyn_cast_or_null<MDNode>(Op))
+ if (!Node->isResolved())
+ Cycles.push_back(Node);
+
+ return NewMD;
+}
+
+/// \brief Map a uniqued MDNode.
+///
+/// Uniqued nodes may not need to be recreated (they may map to themselves).
+static Metadata *mapUniquedNode(const MDNode *Node,
+ SmallVectorImpl<MDNode *> &Cycles,
+ ValueToValueMapTy &VM, RemapFlags Flags,
+ ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
+ assert(Node->isUniqued() && "Expected uniqued node");
+
+ // Create a temporary node upfront in case we have a metadata cycle.
+ auto ClonedMD = Node->clone();
+ if (!remap(Node, ClonedMD.get(), Cycles, VM, Flags, TypeMapper, Materializer))
+ // No operands changed, so use the identity mapping.
+ return mapToSelf(VM, Node);
+
+ // At least one operand has changed, so uniquify the cloned node.
+ return mapToMetadata(VM, Node,
+ MDNode::replaceWithUniqued(std::move(ClonedMD)));
+}
+
+static Metadata *MapMetadataImpl(const Metadata *MD,
+ SmallVectorImpl<MDNode *> &Cycles,
+ ValueToValueMapTy &VM, RemapFlags Flags,
+ ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
+ // If the value already exists in the map, use it.
+ if (Metadata *NewMD = VM.MD().lookup(MD).get())
+ return NewMD;
+
+ if (isa<MDString>(MD))
+ return mapToSelf(VM, MD);
+
+ if (isa<ConstantAsMetadata>(MD))
+ if ((Flags & RF_NoModuleLevelChanges))
+ return mapToSelf(VM, MD);
+
+ if (const auto *VMD = dyn_cast<ValueAsMetadata>(MD)) {
+ Value *MappedV =
+ MapValue(VMD->getValue(), VM, Flags, TypeMapper, Materializer);
+ if (VMD->getValue() == MappedV ||
+ (!MappedV && (Flags & RF_IgnoreMissingEntries)))
+ return mapToSelf(VM, MD);
+
+ // FIXME: This assert crashes during bootstrap, but I think it should be
+ // correct. For now, just match behaviour from before the metadata/value
+ // split.
+ //
+ // assert(MappedV && "Referenced metadata not in value map!");
+ if (MappedV)
+ return mapToMetadata(VM, MD, ValueAsMetadata::get(MappedV));
+ return nullptr;
+ }
+
+ // Note: this cast precedes the Flags check so we always get its associated
+ // assertion.
+ const MDNode *Node = cast<MDNode>(MD);
+
+ // If this is a module-level metadata and we know that nothing at the
+ // module level is changing, then use an identity mapping.
+ if (Flags & RF_NoModuleLevelChanges)
+ return mapToSelf(VM, MD);
+
+ // Require resolved nodes whenever metadata might be remapped.
+ assert(Node->isResolved() && "Unexpected unresolved node");
+
+ if (Node->isDistinct())
+ return mapDistinctNode(Node, Cycles, VM, Flags, TypeMapper, Materializer);
+
+ return mapUniquedNode(Node, Cycles, VM, Flags, TypeMapper, Materializer);
+}
+
+Metadata *llvm::MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
+ RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
+ SmallVector<MDNode *, 8> Cycles;
+ Metadata *NewMD =
+ MapMetadataImpl(MD, Cycles, VM, Flags, TypeMapper, Materializer);
+
+ // Resolve cycles underneath MD.
+ if (NewMD && NewMD != MD) {
+ if (auto *N = dyn_cast<MDNode>(NewMD))
+ if (!N->isResolved())
+ N->resolveCycles();
+
+ for (MDNode *N : Cycles)
+ if (!N->isResolved())
+ N->resolveCycles();
+ } else {
+ // Shouldn't get unresolved cycles if nothing was remapped.
+ assert(Cycles.empty() && "Expected no unresolved cycles");
+ }
+
+ return NewMD;
+}
+
+MDNode *llvm::MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
+ RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
+ ValueMaterializer *Materializer) {
+ return cast<MDNode>(MapMetadata(static_cast<const Metadata *>(MD), VM, Flags,
+ TypeMapper, Materializer));