395 lines
15 KiB
Java
395 lines
15 KiB
Java
/*******************************************************************************
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* This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html.
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*
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* This file is a derivative of code released by the University of
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* California under the terms listed below.
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*
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* Refinement Analysis Tools is Copyright (c) 2007 The Regents of the
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* University of California (Regents). Provided that this notice and
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* the following two paragraphs are included in any distribution of
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* Refinement Analysis Tools or its derivative work, Regents agrees
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* not to assert any of Regents' copyright rights in Refinement
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* Analysis Tools against recipient for recipient's reproduction,
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* preparation of derivative works, public display, public
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* performance, distribution or sublicensing of Refinement Analysis
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* Tools and derivative works, in source code and object code form.
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* This agreement not to assert does not confer, by implication,
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* estoppel, or otherwise any license or rights in any intellectual
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* property of Regents, including, but not limited to, any patents
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* of Regents or Regents' employees.
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*
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* IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT,
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* INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
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* INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE
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* AND ITS DOCUMENTATION, EVEN IF REGENTS HAS BEEN ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE AND FURTHER DISCLAIMS ANY STATUTORY
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* WARRANTY OF NON-INFRINGEMENT. THE SOFTWARE AND ACCOMPANYING
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* DOCUMENTATION, IF ANY, PROVIDED HEREUNDER IS PROVIDED "AS
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* IS". REGENTS HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
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* UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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package com.ibm.wala.demandpa.flowgraph;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.Iterator;
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import java.util.Map;
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import java.util.Set;
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import com.ibm.wala.cfg.ControlFlowGraph;
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import com.ibm.wala.cfg.IBasicBlock;
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import com.ibm.wala.classLoader.CallSiteReference;
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import com.ibm.wala.demandpa.util.MemoryAccessMap;
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import com.ibm.wala.ipa.callgraph.CGNode;
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import com.ibm.wala.ipa.callgraph.CallGraph;
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import com.ibm.wala.ipa.callgraph.propagation.HeapModel;
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import com.ibm.wala.ipa.callgraph.propagation.LocalPointerKey;
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import com.ibm.wala.ipa.callgraph.propagation.PointerKey;
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import com.ibm.wala.ipa.callgraph.propagation.ReturnValueKey;
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import com.ibm.wala.ipa.callgraph.propagation.SSAPropagationCallGraphBuilder;
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import com.ibm.wala.ipa.callgraph.propagation.cfa.CallerSiteContext;
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import com.ibm.wala.ipa.cha.IClassHierarchy;
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import com.ibm.wala.ssa.DefUse;
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import com.ibm.wala.ssa.IR;
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import com.ibm.wala.ssa.ISSABasicBlock;
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import com.ibm.wala.ssa.SSAAbstractInvokeInstruction;
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import com.ibm.wala.ssa.SSAInstruction;
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import com.ibm.wala.ssa.SSAPhiInstruction;
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import com.ibm.wala.util.collections.EmptyIterator;
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import com.ibm.wala.util.collections.HashMapFactory;
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import com.ibm.wala.util.collections.HashSetFactory;
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import com.ibm.wala.util.intset.BitVectorIntSet;
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import com.ibm.wala.util.ref.ReferenceCleanser;
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/**
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* A graph representing program flow, constructed method-by-method on demand
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*/
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public abstract class AbstractDemandFlowGraph extends AbstractFlowGraph {
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private final static boolean DEBUG = false;
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/**
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* Counter for wiping soft caches
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*/
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private static int wipeCount = 0;
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/**
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* node numbers of CGNodes we have already visited
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*/
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final BitVectorIntSet cgNodesVisited = new BitVectorIntSet();
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/*
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* @see com.ibm.wala.demandpa.flowgraph.IFlowGraph#addSubgraphForNode(com.ibm.wala.ipa.callgraph.CGNode)
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*/
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@Override
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public void addSubgraphForNode(CGNode node) throws IllegalArgumentException {
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if (node == null) {
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throw new IllegalArgumentException("node == null");
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}
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IR ir = node.getIR();
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if (ir == null) {
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throw new IllegalArgumentException("no ir for node " + node);
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}
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int n = cg.getNumber(node);
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if (!cgNodesVisited.contains(n)) {
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cgNodesVisited.add(n);
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unconditionallyAddConstraintsFromNode(node, ir);
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addNodesForInvocations(node, ir);
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addNodesForParameters(node, ir);
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}
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}
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/*
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* @see com.ibm.wala.demandpa.flowgraph.IFlowGraph#hasSubgraphForNode(com.ibm.wala.ipa.callgraph.CGNode)
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*/
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@Override
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public boolean hasSubgraphForNode(CGNode node) {
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return cgNodesVisited.contains(cg.getNumber(node));
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}
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/*
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* @see com.ibm.wala.demandpa.flowgraph.IFlowGraph#getParamSuccs(com.ibm.wala.ipa.callgraph.propagation.LocalPointerKey)
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*/
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public Iterator<PointerKeyAndCallSite> getParamSuccs(LocalPointerKey pk) {
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// TODO cache this result
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// TODO take some cgnode as parameter if we have calling context?
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CGNode cgNode = params.get(pk);
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if (cgNode == null) {
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return EmptyIterator.instance();
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}
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int paramPos = pk.getValueNumber() - 1;
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ArrayList<PointerKeyAndCallSite> paramSuccs = new ArrayList<PointerKeyAndCallSite>();
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// iterate over callers
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for (CGNode caller : cg) {
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// TODO optimization: we don't need to add the graph if null is passed
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// as the argument
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addSubgraphForNode(caller);
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IR ir = caller.getIR();
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for (Iterator<CallSiteReference> iterator = ir.iterateCallSites(); iterator.hasNext();) {
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CallSiteReference call = iterator.next();
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if (cg.getPossibleTargets(caller, call).contains(cgNode)) {
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SSAAbstractInvokeInstruction[] callInstrs = ir.getCalls(call);
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for (int i = 0; i < callInstrs.length; i++) {
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SSAAbstractInvokeInstruction callInstr = callInstrs[i];
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PointerKey actualPk = heapModel.getPointerKeyForLocal(caller, callInstr.getUse(paramPos));
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assert containsNode(actualPk);
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assert containsNode(pk);
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paramSuccs.add(new PointerKeyAndCallSite(actualPk, call));
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}
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}
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}
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}
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return paramSuccs.iterator();
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}
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/*
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* @see com.ibm.wala.demandpa.flowgraph.IFlowGraph#getParamPreds(com.ibm.wala.ipa.callgraph.propagation.LocalPointerKey)
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*/
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public Iterator<PointerKeyAndCallSite> getParamPreds(LocalPointerKey pk) {
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// TODO
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Set<SSAAbstractInvokeInstruction> instrs = callParams.get(pk);
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if (instrs == null) {
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return EmptyIterator.instance();
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}
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ArrayList<PointerKeyAndCallSite> paramPreds = new ArrayList<PointerKeyAndCallSite>();
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for (SSAAbstractInvokeInstruction callInstr : instrs) {
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for (int i = 0; i < callInstr.getNumberOfUses(); i++) {
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if (pk.getValueNumber() != callInstr.getUse(i))
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continue;
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CallSiteReference callSiteRef = callInstr.getCallSite();
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// get call targets
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Collection<CGNode> possibleCallees = cg.getPossibleTargets(pk.getNode(), callSiteRef);
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// construct graph for each target
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for (CGNode callee : possibleCallees) {
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addSubgraphForNode(callee);
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// TODO test this!!!
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// TODO test passing null as an argument
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PointerKey paramVal = heapModel.getPointerKeyForLocal(callee, i + 1);
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assert containsNode(paramVal);
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paramPreds.add(new PointerKeyAndCallSite(paramVal, callSiteRef));
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}
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}
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}
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return paramPreds.iterator();
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}
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/*
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* @see com.ibm.wala.demandpa.flowgraph.IFlowGraph#getReturnSuccs(com.ibm.wala.ipa.callgraph.propagation.LocalPointerKey)
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*/
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public Iterator<PointerKeyAndCallSite> getReturnSuccs(LocalPointerKey pk) {
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SSAAbstractInvokeInstruction callInstr = callDefs.get(pk);
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if (callInstr == null)
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return EmptyIterator.instance();
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ArrayList<PointerKeyAndCallSite> returnSuccs = new ArrayList<PointerKeyAndCallSite>();
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boolean isExceptional = pk.getValueNumber() == callInstr.getException();
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CallSiteReference callSiteRef = callInstr.getCallSite();
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// get call targets
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Collection<CGNode> possibleCallees = cg.getPossibleTargets(pk.getNode(), callSiteRef);
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// construct graph for each target
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for (CGNode callee : possibleCallees) {
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addSubgraphForNode(callee);
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PointerKey retVal = isExceptional ? heapModel.getPointerKeyForExceptionalReturnValue(callee) : heapModel
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.getPointerKeyForReturnValue(callee);
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assert containsNode(retVal);
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returnSuccs.add(new PointerKeyAndCallSite(retVal, callSiteRef));
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}
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return returnSuccs.iterator();
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}
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/*
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* @see com.ibm.wala.demandpa.flowgraph.IFlowGraph#getReturnPreds(com.ibm.wala.ipa.callgraph.propagation.LocalPointerKey)
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*/
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public Iterator<PointerKeyAndCallSite> getReturnPreds(LocalPointerKey pk) {
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CGNode cgNode = returns.get(pk);
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if (cgNode == null) {
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return EmptyIterator.instance();
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}
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boolean isExceptional = pk == heapModel.getPointerKeyForExceptionalReturnValue(cgNode);
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ArrayList<PointerKeyAndCallSite> returnPreds = new ArrayList<PointerKeyAndCallSite>();
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// iterate over callers
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for (CGNode caller : cg) {
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// TODO we don't need to add the graph if null is passed
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// as the argument
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addSubgraphForNode(caller);
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IR ir = caller.getIR();
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for (Iterator<CallSiteReference> iterator = ir.iterateCallSites(); iterator.hasNext();) {
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CallSiteReference call = iterator.next();
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if (cg.getPossibleTargets(caller, call).contains(cgNode)) {
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SSAAbstractInvokeInstruction[] callInstrs = ir.getCalls(call);
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for (int i = 0; i < callInstrs.length; i++) {
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SSAAbstractInvokeInstruction callInstr = callInstrs[i];
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PointerKey returnPk = heapModel.getPointerKeyForLocal(caller, isExceptional ? callInstr.getException() : callInstr
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.getDef());
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assert containsNode(returnPk);
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assert containsNode(pk);
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returnPreds.add(new PointerKeyAndCallSite(returnPk, call));
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}
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}
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}
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}
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return returnPreds.iterator();
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}
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protected abstract void addNodesForParameters(CGNode node, IR ir);
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protected void unconditionallyAddConstraintsFromNode(CGNode node, IR ir) {
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if (DEBUG) {
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System.err.println(("Adding constraints for CGNode " + node));
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}
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if (SSAPropagationCallGraphBuilder.PERIODIC_WIPE_SOFT_CACHES) {
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wipeCount++;
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if (wipeCount >= SSAPropagationCallGraphBuilder.WIPE_SOFT_CACHE_INTERVAL) {
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wipeCount = 0;
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ReferenceCleanser.clearSoftCaches();
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}
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}
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debugPrintIR(ir);
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if (ir == null) {
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return;
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}
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DefUse du = node.getDU();
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addNodeInstructionConstraints(node, ir, du);
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addNodePassthruExceptionConstraints(node, ir);
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addNodeConstantConstraints(node, ir);
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}
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/**
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* Add pointer flow constraints based on instructions in a given node
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*/
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protected void addNodeInstructionConstraints(CGNode node, IR ir, DefUse du) {
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FlowStatementVisitor v = makeVisitor(node);
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ControlFlowGraph<SSAInstruction, ISSABasicBlock> cfg = ir.getControlFlowGraph();
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for (ISSABasicBlock b : cfg) {
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addBlockInstructionConstraints(node, cfg, b, v);
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}
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}
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/**
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* Add constraints for a particular basic block.
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*/
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protected void addBlockInstructionConstraints(CGNode node, ControlFlowGraph<SSAInstruction, ISSABasicBlock> cfg,
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ISSABasicBlock b, FlowStatementVisitor v) {
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v.setBasicBlock(b);
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// visit each instruction in the basic block.
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for (Iterator<SSAInstruction> it = b.iterator(); it.hasNext();) {
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SSAInstruction s = it.next();
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if (s != null) {
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s.visit(v);
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}
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}
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addPhiConstraints(node, cfg, b);
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}
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private void addPhiConstraints(CGNode node, ControlFlowGraph<SSAInstruction, ISSABasicBlock> cfg, ISSABasicBlock b) {
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// visit each phi instruction in each successor block
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for (Iterator<? extends IBasicBlock> iter = cfg.getSuccNodes(b); iter.hasNext();) {
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ISSABasicBlock sb = (ISSABasicBlock) iter.next();
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if (sb.isExitBlock()) {
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// an optimization based on invariant that exit blocks should
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// have no
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// phis.
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continue;
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}
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int n = 0;
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// set n to be whichPred(this, sb);
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for (Iterator<? extends IBasicBlock> back = cfg.getPredNodes(sb); back.hasNext(); n++) {
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if (back.next() == b) {
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break;
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}
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}
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assert n < cfg.getPredNodeCount(sb);
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for (Iterator<SSAPhiInstruction> phis = sb.iteratePhis(); phis.hasNext();) {
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// Assertions.UNREACHABLE();
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SSAPhiInstruction phi = phis.next();
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if (phi == null) {
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continue;
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}
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PointerKey def = heapModel.getPointerKeyForLocal(node, phi.getDef());
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if (phi.getUse(n) > 0) {
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PointerKey use = heapModel.getPointerKeyForLocal(node, phi.getUse(n));
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addNode(def);
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addNode(use);
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addEdge(def, use, AssignLabel.noFilter());
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}
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// }
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// }
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}
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}
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}
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protected abstract FlowStatementVisitor makeVisitor(CGNode node);
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private static void debugPrintIR(IR ir) {
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if (DEBUG) {
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if (ir == null) {
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System.err.println("\n No statements\n");
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} else {
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try {
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System.err.println(ir.toString());
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} catch (Error e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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}
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}
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}
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final Map<CGNode, Set<CallerSiteContext>> callerCache = HashMapFactory.make();
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@Override
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public Set<CallerSiteContext> getPotentialCallers(PointerKey formalPk) {
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CGNode callee = null;
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if (formalPk instanceof LocalPointerKey) {
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callee = ((LocalPointerKey) formalPk).getNode();
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} else if (formalPk instanceof ReturnValueKey) {
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callee = ((ReturnValueKey) formalPk).getNode();
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} else {
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throw new IllegalArgumentException("formalPk must represent a local");
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}
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Set<CallerSiteContext> ret = callerCache.get(callee);
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if (ret == null) {
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ret = HashSetFactory.make();
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for (Iterator<? extends CGNode> predNodes = cg.getPredNodes(callee); predNodes.hasNext();) {
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CGNode caller = predNodes.next();
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for (Iterator<CallSiteReference> iterator = cg.getPossibleSites(caller, callee); iterator.hasNext();) {
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CallSiteReference call = iterator.next();
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ret.add(new CallerSiteContext(caller, call));
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}
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}
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callerCache.put(callee, ret);
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}
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return ret;
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}
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@Override
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public Set<CGNode> getPossibleTargets(CGNode node, CallSiteReference site, LocalPointerKey actualPk) {
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return cg.getPossibleTargets(node, site);
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}
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protected interface FlowStatementVisitor extends SSAInstruction.IVisitor {
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void setBasicBlock(ISSABasicBlock b);
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}
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public AbstractDemandFlowGraph(final CallGraph cg, final HeapModel heapModel, final MemoryAccessMap mam, final IClassHierarchy cha) {
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super(mam, heapModel, cha, cg);
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}
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}
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