@override

HInstruction visitInstanceEnvironment(HInstanceEnvironment node) {

HInstruction instance = node.inputs.single;

// Store-forward instance types of created instances and constant instances.

//

// Forwarding the type might cause the instance (HCreate, constant etc) to

// become dead. This might cause us to lose track of that fact that there

// are type expressions from within the instance's class scope, so breaking

// the algorithm for generating the per-type runtime type information. The

// fix is to register the classes as created here in case the instance

// becomes dead.

//

// TODO(sra): It would be cleaner to track on HLoadType, HTypeEval, etc

// which class scope(s) they originated from. If the type expressions become

// dead, the references to the scope type variables become dead.

if (instance is HCreate) {

if (instance.hasRtiInput) {

instance.instantiatedTypes?.forEach(_registry.registerInstantiation);

return instance.inputs.last;

}

return node;

}

if (instance is HConstant) {

ConstantValue constantValue = instance.constant;

if (constantValue is ConstructedConstantValue) {

_registry.registerInstantiation(constantValue.type);

return HLoadType(constantValue.type, instance.instructionType);

}

return node;

}

// TODO(sra): Store-forward list literal types.

return node;

}