+ValueAsMetadata *ValueAsMetadata::getIfExists(Value *V) {
+ assert(V && "Unexpected null Value");
+ return V->getContext().pImpl->ValuesAsMetadata.lookup(V);
+}
+
+void ValueAsMetadata::handleDeletion(Value *V) {
+ assert(V && "Expected valid value");
+
+ auto &Store = V->getType()->getContext().pImpl->ValuesAsMetadata;
+ auto I = Store.find(V);
+ if (I == Store.end())
+ return;
+
+ // Remove old entry from the map.
+ ValueAsMetadata *MD = I->second;
+ assert(MD && "Expected valid metadata");
+ assert(MD->getValue() == V && "Expected valid mapping");
+ Store.erase(I);
+
+ // Delete the metadata.
+ MD->replaceAllUsesWith(nullptr);
+ delete MD;
+}
+
+void ValueAsMetadata::handleRAUW(Value *From, Value *To) {
+ assert(From && "Expected valid value");
+ assert(To && "Expected valid value");
+ assert(From != To && "Expected changed value");
+ assert(From->getType() == To->getType() && "Unexpected type change");
+
+ LLVMContext &Context = From->getType()->getContext();
+ auto &Store = Context.pImpl->ValuesAsMetadata;
+ auto I = Store.find(From);
+ if (I == Store.end()) {
+ assert(!From->NameAndIsUsedByMD.getInt() &&
+ "Expected From not to be used by metadata");
+ return;
+ }
+
+ // Remove old entry from the map.
+ assert(From->NameAndIsUsedByMD.getInt() &&
+ "Expected From to be used by metadata");
+ From->NameAndIsUsedByMD.setInt(false);
+ ValueAsMetadata *MD = I->second;
+ assert(MD && "Expected valid metadata");
+ assert(MD->getValue() == From && "Expected valid mapping");
+ Store.erase(I);
+
+ if (isa<LocalAsMetadata>(MD)) {
+ if (auto *C = dyn_cast<Constant>(To)) {
+ // Local became a constant.
+ MD->replaceAllUsesWith(ConstantAsMetadata::get(C));
+ delete MD;
+ return;
+ }
+ if (getLocalFunction(From) && getLocalFunction(To) &&
+ getLocalFunction(From) != getLocalFunction(To)) {
+ // Function changed.
+ MD->replaceAllUsesWith(nullptr);
+ delete MD;
+ return;
+ }
+ } else if (!isa<Constant>(To)) {
+ // Changed to function-local value.
+ MD->replaceAllUsesWith(nullptr);
+ delete MD;
+ return;
+ }
+
+ auto *&Entry = Store[To];
+ if (Entry) {
+ // The target already exists.
+ MD->replaceAllUsesWith(Entry);
+ delete MD;
+ return;
+ }
+
+ // Update MD in place (and update the map entry).
+ assert(!To->NameAndIsUsedByMD.getInt() &&
+ "Expected this to be the only metadata use");
+ To->NameAndIsUsedByMD.setInt(true);
+ MD->V = To;
+ Entry = MD;
+}
+
+//===----------------------------------------------------------------------===//
+// MDString implementation.
+//
+
+MDString *MDString::get(LLVMContext &Context, StringRef Str) {
+ auto &Store = Context.pImpl->MDStringCache;
+ auto I = Store.find(Str);
+ if (I != Store.end())
+ return &I->second;
+
+ auto *Entry =
+ StringMapEntry<MDString>::Create(Str, Store.getAllocator(), MDString());
+ bool WasInserted = Store.insert(Entry);
+ (void)WasInserted;
+ assert(WasInserted && "Expected entry to be inserted");
+ Entry->second.Entry = Entry;
+ return &Entry->second;
+}
+
+StringRef MDString::getString() const {
+ assert(Entry && "Expected to find string map entry");
+ return Entry->first();