Examples with LocalVariableNode org.checkerframework.dataflow.cfg.node.LocalVariableNode used on opensource projects

Example 6 with LocalVariableNode

use of org.checkerframework.dataflow.cfg.node.LocalVariableNode in project error-prone by google.

the class NullnessPropagationTransfer method handleEqualityComparison.

/**
   * Refines the {@code Nullness} of {@code LocalVariableNode}s used in an equality comparison using
   * the greatest lower bound.
   *
   * @param equalTo whether the comparison is == (false for !=)
   * @param leftNode the left-hand side of the comparison
   * @param rightNode the right-hand side of the comparison
   * @param inputs access to nullness values of the left and right nodes
   * @param thenUpdates the local variables whose nullness values should be updated if the
   *     comparison returns {@code true}
   * @param elseUpdates the local variables whose nullness values should be updated if the
   *     comparison returns {@code false}
   */
private static void handleEqualityComparison(boolean equalTo, Node leftNode, Node rightNode, SubNodeValues inputs, LocalVariableUpdates thenUpdates, LocalVariableUpdates elseUpdates) {
    Nullness leftVal = inputs.valueOfSubNode(leftNode);
    Nullness rightVal = inputs.valueOfSubNode(rightNode);
    Nullness equalBranchValue = leftVal.greatestLowerBound(rightVal);
    LocalVariableUpdates equalBranchUpdates = equalTo ? thenUpdates : elseUpdates;
    LocalVariableUpdates notEqualBranchUpdates = equalTo ? elseUpdates : thenUpdates;
    if (leftNode instanceof LocalVariableNode) {
        LocalVariableNode localVar = (LocalVariableNode) leftNode;
        equalBranchUpdates.set(localVar, equalBranchValue);
        notEqualBranchUpdates.set(localVar, leftVal.greatestLowerBound(rightVal.deducedValueWhenNotEqual()));
    }
    if (rightNode instanceof LocalVariableNode) {
        LocalVariableNode localVar = (LocalVariableNode) rightNode;
        equalBranchUpdates.set(localVar, equalBranchValue);
        notEqualBranchUpdates.set(localVar, rightVal.greatestLowerBound(leftVal.deducedValueWhenNotEqual()));
    }
}

Example 7 with LocalVariableNode

use of org.checkerframework.dataflow.cfg.node.LocalVariableNode in project error-prone by google.

the class NullnessPropagationTransfer method visitAssignment.

@Override
Nullness visitAssignment(AssignmentNode node, SubNodeValues inputs, LocalVariableUpdates updates) {
    Nullness value = inputs.valueOfSubNode(node.getExpression());
    Node target = node.getTarget();
    if (target instanceof LocalVariableNode) {
        updates.set((LocalVariableNode) target, value);
    }
    if (target instanceof ArrayAccessNode) {
        setNonnullIfLocalVariable(updates, ((ArrayAccessNode) target).getArray());
    }
    if (target instanceof FieldAccessNode) {
        FieldAccessNode fieldAccess = (FieldAccessNode) target;
        ClassAndField targetField = tryGetFieldSymbol(target.getTree());
        setReceiverNonnull(updates, fieldAccess.getReceiver(), targetField);
    }
    /*
     * We propagate the value of the target to the value of the assignment expressions as a whole.
     * We do this regardless of whether the target is a local variable. For example:
     *
     * String s = object.field = "foo"; // Now |s| is non-null.
     *
     * It's not clear to me that this is technically correct, but it works in practice with the
     * bytecode generated by both javac and ecj.
     *
     * http://stackoverflow.com/q/12850676/28465
     */
    return value;
}