Java 类jdk.nashorn.internal.ir.Assignment 实例源码

<T extends Expression> SpecializedNode specialize(final Assignment<T> assignment) {
    final Node node = ((Node)assignment);
    final T lhs = assignment.getAssignmentDest();
    final Expression rhs = assignment.getAssignmentSource();

    if (!canHaveCallSiteType(lhs)) {
        return new SpecializedNode(node, null);
    }

    final Type to;
    if (node.isSelfModifying()) {
        to = node.getWidestOperationType();
    } else {
        to = rhs.getType();
    }

    if (!isSupportedCallSiteType(to)) {
        //meaningless to specialize to boolean or object
        return new SpecializedNode(node, null);
    }

    final Node newNode = assignment.setAssignmentDest(setTypeOverride(lhs, to));
    final Node typePropagatedNode;
    if(newNode instanceof Expression) {
        typePropagatedNode = propagateType((Expression)newNode, to);
    } else if(newNode instanceof VarNode) {
        // VarNode, being a statement, doesn't have its own symbol; it uses the symbol of its name instead.
        final VarNode varNode = (VarNode)newNode;
        typePropagatedNode = varNode.setName((IdentNode)propagateType(varNode.getName(), to));
    } else {
        throw new AssertionError();
    }
    return new SpecializedNode(typePropagatedNode, to);
}

<T extends Expression> SpecializedNode specialize(final Assignment<T> assignment) {
    final Node node = ((Node)assignment);
    final T lhs = assignment.getAssignmentDest();
    final Expression rhs = assignment.getAssignmentSource();

    if (!canHaveCallSiteType(lhs)) {
        return new SpecializedNode(node, null);
    }

    final Type to;
    if (node.isSelfModifying()) {
        to = node.getWidestOperationType();
    } else {
        to = rhs.getType();
    }

    if (!isSupportedCallSiteType(to)) {
        //meaningless to specialize to boolean or object
        return new SpecializedNode(node, null);
    }

    final Node newNode = assignment.setAssignmentDest(setTypeOverride(lhs, to));
    final Node typePropagatedNode;
    if(newNode instanceof Expression) {
        typePropagatedNode = propagateType((Expression)newNode, to);
    } else if(newNode instanceof VarNode) {
        // VarNode, being a statement, doesn't have its own symbol; it uses the symbol of its name instead.
        final VarNode varNode = (VarNode)newNode;
        typePropagatedNode = varNode.setName((IdentNode)propagateType(varNode.getName(), to));
    } else {
        throw new AssertionError();
    }
    return new SpecializedNode(typePropagatedNode, to);
}