Class SideEffect

src/main/java/pascal/taie/analysis/sideeffect/SideEffect.java:41–105

Represents result of side-effect analysis.

 * Represents result of side-effect analysis.
 */
public class SideEffect implements StmtResult<Set<Obj>> {

    /**
     * Maps from a method to all objects directly or indirectly modified by it.
     */
    private final Map<JMethod, Set<Obj>> methodMods;

    /**
     * Maps from a stmt to the objects directly modified by it.
     */
    private final Map<Stmt, Set<Obj>> stmtDirectMods;

    private final CallGraph<Invoke, JMethod> callGraph;

    SideEffect(Map<JMethod, Set<Obj>> methodMods,
               Map<Stmt, Set<Obj>> stmtDirectMods,
               CallGraph<Invoke, JMethod> callGraph) {
        this.methodMods = methodMods;
        this.stmtDirectMods = stmtDirectMods;
        this.callGraph = callGraph;
    }

    /**
     * @return set of objects that may be modified by given method.
     */
    public Set<Obj> getModifiedObjects(JMethod method) {
        return methodMods.getOrDefault(method, Set.of());
    }

    /**
     * @return set of objects that may be modified by given stmt.
     */
    public Set<Obj> getModifiedObjects(Stmt stmt) {
        if (stmt instanceof Invoke invoke) {
            // to save space, we compute modified objects of
            // Invoke stmt on demand, and do not cache them
            return callGraph.getCalleesOf(invoke)
                    .stream()
                    .map(this::getModifiedObjects)
                    .flatMap(Set::stream)
                    .collect(Collectors.toUnmodifiableSet());
        }
        return stmtDirectMods.getOrDefault(stmt, Set.of());
    }

    /**
     * @return {@code true} if given method does not modify any objects.
     */
    public boolean isPure(JMethod method) {
        return !methodMods.containsKey(method);
    }

    @Override
    public boolean isRelevant(Stmt stmt) {
        return stmt instanceof Invoke ||
                stmt instanceof StoreArray ||
                (stmt instanceof StoreField storeField &&
                        !storeField.isStatic());