| package org.checkerframework.dataflow.analysis; |
| |
| /*>>> |
| import org.checkerframework.checker.nullness.qual.Nullable; |
| */ |
| |
| import org.checkerframework.dataflow.cfg.node.Node; |
| import org.checkerframework.dataflow.util.HashCodeUtils; |
| |
| /** |
| * {@code TransferInput} is used as the input type of the individual transfer functions of a {@link |
| * TransferFunction}. It also contains a reference to the node for which the transfer function will |
| * be applied. |
| * |
| * <p>A {@code TransferInput} contains one or two stores. If two stores are present, one belongs to |
| * 'then', and the other to 'else'. |
| * |
| * @author Stefan Heule |
| * @param <S> the {@link Store} used to keep track of intermediate results |
| */ |
| public class TransferInput<A extends AbstractValue<A>, S extends Store<S>> { |
| |
| /** The corresponding node. */ |
| protected Node node; |
| |
| /** |
| * The regular result store (or {@code null} if none is present). The following invariant is |
| * maintained: |
| * |
| * <pre>{@code |
| * store == null ⇔ thenStore != null && elseStore != null |
| * }</pre> |
| */ |
| protected final /*@Nullable*/ S store; |
| |
| /** |
| * The 'then' result store (or {@code null} if none is present). The following invariant is |
| * maintained: |
| * |
| * <pre>{@code |
| * store == null ⇔ thenStore != null && elseStore != null |
| * }</pre> |
| */ |
| protected final /*@Nullable*/ S thenStore; |
| |
| /** |
| * The 'else' result store (or {@code null} if none is present). The following invariant is |
| * maintained: |
| * |
| * <pre>{@code |
| * store == null ⇔ thenStore != null && elseStore != null |
| * }</pre> |
| */ |
| protected final /*@Nullable*/ S elseStore; |
| |
| /** The corresponding analysis class to get intermediate flow results. */ |
| protected final Analysis<A, S, ?> analysis; |
| |
| /** |
| * Create a {@link TransferInput}, given a {@link TransferResult} and a node-value mapping. |
| * |
| * <p><em>Aliasing</em>: The stores returned by any methods of {@code to} will be stored |
| * internally and are not allowed to be used elsewhere. Full control of them is transfered to |
| * this object. |
| * |
| * <p>The node-value mapping {@code nodeValues} is provided by the analysis and is only read |
| * from within this {@link TransferInput}. |
| */ |
| public TransferInput(Node n, Analysis<A, S, ?> analysis, TransferResult<A, S> to) { |
| node = n; |
| this.analysis = analysis; |
| if (to.containsTwoStores()) { |
| thenStore = to.getThenStore(); |
| elseStore = to.getElseStore(); |
| store = null; |
| } else { |
| store = to.getRegularStore(); |
| thenStore = elseStore = null; |
| } |
| } |
| |
| /** |
| * Create a {@link TransferInput}, given a store and a node-value mapping. |
| * |
| * <p><em>Aliasing</em>: The store {@code s} will be stored internally and is not allowed to be |
| * used elsewhere. Full control over {@code s} is transfered to this object. |
| * |
| * <p>The node-value mapping {@code nodeValues} is provided by the analysis and is only read |
| * from within this {@link TransferInput}. |
| */ |
| public TransferInput(Node n, Analysis<A, S, ?> analysis, S s) { |
| node = n; |
| this.analysis = analysis; |
| store = s; |
| thenStore = elseStore = null; |
| } |
| |
| /** |
| * Create a {@link TransferInput}, given two stores and a node-value mapping. |
| * |
| * <p><em>Aliasing</em>: The two stores {@code s1} and {@code s2} will be stored internally and |
| * are not allowed to be used elsewhere. Full control of them is transfered to this object. |
| */ |
| public TransferInput(Node n, Analysis<A, S, ?> analysis, S s1, S s2) { |
| node = n; |
| this.analysis = analysis; |
| thenStore = s1; |
| elseStore = s2; |
| store = null; |
| } |
| |
| /** Copy constructor. */ |
| protected TransferInput(TransferInput<A, S> from) { |
| this.node = from.node; |
| this.analysis = from.analysis; |
| if (from.store == null) { |
| thenStore = from.thenStore.copy(); |
| elseStore = from.elseStore.copy(); |
| store = null; |
| } else { |
| store = from.store.copy(); |
| thenStore = elseStore = null; |
| } |
| } |
| |
| /** @return the {@link Node} for this {@link TransferInput}. */ |
| public Node getNode() { |
| return node; |
| } |
| |
| /** |
| * @return the abstract value of {@link Node} {@code n}, which is required to be a 'sub-node' |
| * (that is, a direct or indirect child) of the node this transfer input is associated with. |
| * Furthermore, {@code n} cannot be a l-value node. Returns {@code null} if no value if |
| * available. |
| */ |
| public /*@Nullable*/ A getValueOfSubNode(Node n) { |
| return analysis.getValue(n); |
| } |
| |
| /** |
| * @return the regular result store produced if no exception is thrown by the {@link Node} |
| * corresponding to this transfer function result |
| */ |
| public S getRegularStore() { |
| if (store == null) { |
| return thenStore.leastUpperBound(elseStore); |
| } else { |
| return store; |
| } |
| } |
| |
| /** |
| * @return the result store produced if the {@link Node} this result belongs to evaluates to |
| * {@code true}. |
| */ |
| public S getThenStore() { |
| if (store == null) { |
| return thenStore; |
| } |
| return store; |
| } |
| |
| /** |
| * @return the result store produced if the {@link Node} this result belongs to evaluates to |
| * {@code false}. |
| */ |
| public S getElseStore() { |
| if (store == null) { |
| return elseStore; |
| } |
| // copy the store such that it is the same as the result of getThenStore |
| // (that is, identical according to equals), but two different objects. |
| return store.copy(); |
| } |
| |
| /** |
| * @return {@code true} if and only if this transfer input contains two stores that are |
| * potentially not equal. Note that the result {@code true} does not imply that {@code |
| * getRegularStore} cannot be called (or vice versa for {@code false}). Rather, it indicates |
| * that {@code getThenStore} or {@code getElseStore} can be used to give more precise |
| * results. Otherwise, if the result is {@code false}, then all three methods {@code |
| * getRegularStore}, {@code getThenStore}, and {@code getElseStore} return equivalent |
| * stores. |
| */ |
| public boolean containsTwoStores() { |
| return (thenStore != null && elseStore != null); |
| } |
| |
| /** @return an exact copy of this store. */ |
| public TransferInput<A, S> copy() { |
| return new TransferInput<>(this); |
| } |
| |
| /** |
| * Compute the least upper bound of two stores. |
| * |
| * <p><em>Important</em>: This method must fulfill the same contract as {@code leastUpperBound} |
| * of {@link Store}. |
| */ |
| public TransferInput<A, S> leastUpperBound(TransferInput<A, S> other) { |
| if (store == null) { |
| S newThenStore = thenStore.leastUpperBound(other.getThenStore()); |
| S newElseStore = elseStore.leastUpperBound(other.getElseStore()); |
| return new TransferInput<>(node, analysis, newThenStore, newElseStore); |
| } else { |
| if (other.store == null) { |
| // make sure we do not lose precision and keep two stores if at |
| // least one of the two TransferInput's has two stores. |
| return other.leastUpperBound(this); |
| } |
| return new TransferInput<>( |
| node, analysis, store.leastUpperBound(other.getRegularStore())); |
| } |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (o != null && o instanceof TransferInput) { |
| @SuppressWarnings("unchecked") |
| TransferInput<A, S> other = (TransferInput<A, S>) o; |
| if (containsTwoStores()) { |
| if (other.containsTwoStores()) { |
| return getThenStore().equals(other.getThenStore()) |
| && getElseStore().equals(other.getElseStore()); |
| } |
| } else { |
| if (!other.containsTwoStores()) { |
| return getRegularStore().equals(other.getRegularStore()); |
| } |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public int hashCode() { |
| return HashCodeUtils.hash( |
| this.analysis, this.node, this.store, this.thenStore, this.elseStore); |
| } |
| |
| @Override |
| public String toString() { |
| if (store == null) { |
| return "[then=" + thenStore + ", else=" + elseStore + "]"; |
| } else { |
| return "[" + store + "]"; |
| } |
| } |
| } |
