Java 类org.apache.bcel.generic.ReturnaddressType 实例源码

/**
 * Merges two {@link Type}s into one.
 *
 * @param errorIfFailed
 *      if true, attempting to merge two types that are incompatible causes an error.
 *      if false, it yields {@link Type#UNKNOWN} value, indicating that value is unusable.
 */
/*package*/ static Type merge(Type lhs, Type rhs, boolean errorIfFailed) {
    try {

        // We won't accept an unitialized object if we know it was initialized;
        // compare vmspec2, 4.9.4, last paragraph.
        if ((!(lhs instanceof UninitializedObjectType)) && (rhs instanceof UninitializedObjectType)) {
            throw new StructuralCodeConstraintException("Backwards branch with an uninitialized object in the local variables detected.");
        }
        // Even harder, what about _different_ uninitialized object types?!
        if ((!(lhs.equals(rhs))) && (lhs instanceof UninitializedObjectType) && (rhs instanceof UninitializedObjectType)) {
            throw new StructuralCodeConstraintException("Backwards branch with an uninitialized object in the local variables detected.");
        }
        // If we just didn't know that it was initialized, we have now learned.
        if (lhs instanceof UninitializedObjectType) {
            if (! (rhs instanceof UninitializedObjectType)) {
                lhs = ((UninitializedObjectType) lhs).getInitialized();
            }
        }
        if ((lhs instanceof ReferenceType) && (rhs instanceof ReferenceType)) {
            if(lhs.equals(rhs)) {
                return lhs; // same type
            }

            Type sup = ((ReferenceType) lhs).getFirstCommonSuperclass((ReferenceType) rhs);

            if (sup != null) {
                return sup;
            } else {
                // We should have checked this in Pass2!
                throw new AssertionViolatedException("Could not load all the super classes of '" + lhs + "' and '" + rhs + "'.");
            }
        }

        if ((lhs instanceof ReturnaddressType) && (rhs instanceof ReturnaddressType)) {
            // see 'FinallyFlow' test.
            return lhs;
        }

        if (!lhs.equals(rhs)) {
            if(errorIfFailed) {
                throw new StructuralCodeConstraintException("Cannot merge different types:"+lhs+" and "+rhs);
            } else {
                return Type.UNKNOWN;
            }
        }

        return lhs;
    } catch (ClassNotFoundException e) {
        // FIXME: maybe not the best way to handle this
        throw new AssertionViolatedException("Missing class: " + e.toString());
    }
}

/**
 * Merges two {@link Type}s into one.
 *
 * @param errorIfFailed
 *      if true, attempting to merge two types that are incompatible causes an error.
 *      if false, it yields {@link Type#UNKNOWN} value, indicating that value is unusable.
 */
/*package*/ static Type merge(Type lhs, Type rhs, boolean errorIfFailed) {
    try {

        // We won't accept an unitialized object if we know it was initialized;
        // compare vmspec2, 4.9.4, last paragraph.
        if ((!(lhs instanceof UninitializedObjectType)) && (rhs instanceof UninitializedObjectType)) {
            throw new StructuralCodeConstraintException("Backwards branch with an uninitialized object in the local variables detected.");
        }
        // Even harder, what about _different_ uninitialized object types?!
        if ((!(lhs.equals(rhs))) && (lhs instanceof UninitializedObjectType) && (rhs instanceof UninitializedObjectType)) {
            throw new StructuralCodeConstraintException("Backwards branch with an uninitialized object in the local variables detected.");
        }
        // If we just didn't know that it was initialized, we have now learned.
        if (lhs instanceof UninitializedObjectType) {
            if (! (rhs instanceof UninitializedObjectType)) {
                lhs = ((UninitializedObjectType) lhs).getInitialized();
            }
        }
        if ((lhs instanceof ReferenceType) && (rhs instanceof ReferenceType)) {
            if(lhs.equals(rhs)) {
                return lhs; // same type
            }

            Type sup = ((ReferenceType) lhs).getFirstCommonSuperclass((ReferenceType) rhs);

            if (sup != null) {
                return sup;
            } else {
                // We should have checked this in Pass2!
                throw new AssertionViolatedException("Could not load all the super classes of '" + lhs + "' and '" + rhs + "'.");
            }
        }

        if ((lhs instanceof ReturnaddressType) && (rhs instanceof ReturnaddressType)) {
            // see 'FinallyFlow' test.
            return lhs;
        }

        if (!lhs.equals(rhs)) {
            if(errorIfFailed) {
                throw new StructuralCodeConstraintException("Cannot merge different types:"+lhs+" and "+rhs);
            } else {
                return Type.UNKNOWN;
            }
        }

        return lhs;
    } catch (ClassNotFoundException e) {
        // FIXME: maybe not the best way to handle this
        throw new AssertionViolatedException("Missing class: " + e.toString());
    }
}