+MetadataAsValue *MetadataAsValue::getIfExists(LLVMContext &Context,
+ Metadata *MD) {
+ MD = canonicalizeMetadataForValue(Context, MD);
+ auto &Store = Context.pImpl->MetadataAsValues;
+ return Store.lookup(MD);
+}
+
+void MetadataAsValue::handleChangedMetadata(Metadata *MD) {
+ LLVMContext &Context = getContext();
+ MD = canonicalizeMetadataForValue(Context, MD);
+ auto &Store = Context.pImpl->MetadataAsValues;
+
+ // Stop tracking the old metadata.
+ Store.erase(this->MD);
+ untrack();
+ this->MD = nullptr;
+
+ // Start tracking MD, or RAUW if necessary.
+ auto *&Entry = Store[MD];
+ if (Entry) {
+ replaceAllUsesWith(Entry);
+ delete this;
+ return;
+ }
+
+ this->MD = MD;
+ track();
+ Entry = this;
+}
+
+void MetadataAsValue::track() {
+ if (MD)
+ MetadataTracking::track(&MD, *MD, *this);
+}
+
+void MetadataAsValue::untrack() {
+ if (MD)
+ MetadataTracking::untrack(MD);
+}
+
+void ReplaceableMetadataImpl::addRef(void *Ref, OwnerTy Owner) {
+ bool WasInserted =
+ UseMap.insert(std::make_pair(Ref, std::make_pair(Owner, NextIndex)))
+ .second;
+ (void)WasInserted;
+ assert(WasInserted && "Expected to add a reference");
+
+ ++NextIndex;
+ assert(NextIndex != 0 && "Unexpected overflow");
+}
+
+void ReplaceableMetadataImpl::dropRef(void *Ref) {
+ bool WasErased = UseMap.erase(Ref);
+ (void)WasErased;
+ assert(WasErased && "Expected to drop a reference");
+}
+
+void ReplaceableMetadataImpl::moveRef(void *Ref, void *New,
+ const Metadata &MD) {
+ auto I = UseMap.find(Ref);
+ assert(I != UseMap.end() && "Expected to move a reference");
+ auto OwnerAndIndex = I->second;
+ UseMap.erase(I);
+ bool WasInserted = UseMap.insert(std::make_pair(New, OwnerAndIndex)).second;
+ (void)WasInserted;
+ assert(WasInserted && "Expected to add a reference");
+
+ // Check that the references are direct if there's no owner.
+ (void)MD;
+ assert((OwnerAndIndex.first || *static_cast<Metadata **>(Ref) == &MD) &&
+ "Reference without owner must be direct");
+ assert((OwnerAndIndex.first || *static_cast<Metadata **>(New) == &MD) &&
+ "Reference without owner must be direct");
+}
+
+void ReplaceableMetadataImpl::replaceAllUsesWith(Metadata *MD) {
+ assert(!(MD && isa<MDNode>(MD) && cast<MDNode>(MD)->isTemporary()) &&
+ "Expected non-temp node");
+
+ if (UseMap.empty())
+ return;
+
+ // Copy out uses since UseMap will get touched below.
+ typedef std::pair<void *, std::pair<OwnerTy, uint64_t>> UseTy;
+ SmallVector<UseTy, 8> Uses(UseMap.begin(), UseMap.end());
+ std::sort(Uses.begin(), Uses.end(), [](const UseTy &L, const UseTy &R) {
+ return L.second.second < R.second.second;
+ });
+ for (const auto &Pair : Uses) {
+ // Check that this Ref hasn't disappeared after RAUW (when updating a
+ // previous Ref).
+ if (!UseMap.count(Pair.first))
+ continue;
+
+ OwnerTy Owner = Pair.second.first;
+ if (!Owner) {
+ // Update unowned tracking references directly.
+ Metadata *&Ref = *static_cast<Metadata **>(Pair.first);
+ Ref = MD;
+ if (MD)
+ MetadataTracking::track(Ref);
+ UseMap.erase(Pair.first);
+ continue;
+ }
+
+ // Check for MetadataAsValue.
+ if (Owner.is<MetadataAsValue *>()) {
+ Owner.get<MetadataAsValue *>()->handleChangedMetadata(MD);
+ continue;
+ }
+
+ // There's a Metadata owner -- dispatch.
+ Metadata *OwnerMD = Owner.get<Metadata *>();
+ switch (OwnerMD->getMetadataID()) {
+#define HANDLE_METADATA_LEAF(CLASS) \
+ case Metadata::CLASS##Kind: \
+ cast<CLASS>(OwnerMD)->handleChangedOperand(Pair.first, MD); \
+ continue;
+#include "llvm/IR/Metadata.def"
+ default:
+ llvm_unreachable("Invalid metadata subclass");
+ }
+ }
+ assert(UseMap.empty() && "Expected all uses to be replaced");
+}