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/**
 * Copyright (C) 2010-2018 Gordon Fraser, Andrea Arcuri and EvoSuite
 * contributors
 *
 * This file is part of EvoSuite.
 *
 * EvoSuite is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3.0 of the License, or
 * (at your option) any later version.
 *
 * EvoSuite is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with EvoSuite. If not, see .
 */
package org.evosuite.graphs.ccfg;

import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.evosuite.graphs.EvoSuiteGraph;
import org.evosuite.graphs.GraphPool;
import org.evosuite.graphs.ccg.ClassCallGraph;
import org.evosuite.graphs.ccg.ClassCallNode;
import org.evosuite.graphs.cfg.BytecodeInstruction;
import org.evosuite.graphs.cfg.ControlFlowEdge;
import org.evosuite.graphs.cfg.RawControlFlowGraph;
import org.evosuite.utils.JdkPureMethodsList;
import org.objectweb.asm.Type;

/**
 * This class computes the Class Control Flow Graph (CCFG) of a CUT.
 * 
 * Given the ClassCallGraph the CCFG is generated as follows:
 * 
 * The RawControlFlowGraph (CFG) of each method in the target class is retrieved
 * from the GraphPool and imported into this CCFG. BytecodeInstructions are
 * imported as CCFGCodeNodes and ControlFlowEdges as CCFGCodeEdges. Additionally
 * each CFG is enclosed by a CCFGMethodEntryNode and CCFGMethodExitNode with an
 * edge from the entry node to the first instruction in the CFG and an edge from
 * each exit instruction in the CFG to the exit node.
 * 
 * After that each method call instruction as defined in
 * BytecodeInstruction.isMethodCall() is replaced by two new nodes
 * CCFGMethodCallNode and CCFGMethodReturnNode that are labeled with that call
 * instruction. Each incoming edge to the previous CCFGCodeNode is redirected to
 * the CCFGMethodCallNode and each outgoing edge from the previous node is
 * redirected to the CCFGMethodReturnNode. Then two CCFGMethodCallEdges are
 * added. One from the CCFGMethodCallNode to the CCFGMethodEntryNode of the
 * called method and one from that methods CCFGMethodExitNode to the
 * CCFGMethodReturnNode. NOTE: Not every method call is replaced like this. Only
 * calls to methods of the class this CCFG is created for that are either static
 * methods - as defined by BytecodeInstruction.isStaticMethodCall() - or calls
 * to methods on the same object (this) as defined by
 * BytecodeInstruction.isMethodCallOnSameObject().
 * 
 * All this is enclosed by a frame consisting of five CCFGFrameNodes of
 * different types. This frame has two dedicated ENTRY and EXIT nodes connected
 * via a third node LOOP. The LOOP node has an outgoing edge to CALL which in
 * turn has an outgoing edge to each CCFGMethodEntryNode of each public method
 * in this graph. Analogously the CCFGMethodExitNode of each public method has
 * an outgoing edge to the CCFGFrameNode RETURN which in turn has an outgoing
 * edge back to LOOP. All these edges are CCFGFrameEdges.
 * 
 * The frame simulates the possible calls to the CUT a test can potentially
 * make. After starting (ENTRY->LOOP) a test can make arbitrary calls to public
 * methods (LOOP->CALL) that can in turn call other methods of the class
 * (CCFGMethodCallEdges). After returning from a public method call
 * (RETURN->LOOP) the test can either make more calls to the class (LOOP->CALL)
 * or stop (LOOP->EXIT).
 * 
 * The construction of the CCFG is inspired by: Proc. of the Second ACM SIGSOFT
 * Symp. on the Foundations of Softw. Eng., December 1994, pages 154-164
 * "Performing Data Flow Testing on Classes" Mary Jean Harrold and Gregg
 * Rothermel, Section 5. The resulting CCFG should be as described in the paper
 * but our construction differs a little (we don't import the CCG and then
 * replace method nodes with CFGs but rather import CFGs and connect them
 * directly).
 * 
 * @author Andre Mis
 */
public class ClassControlFlowGraph extends EvoSuiteGraph {

	public enum FrameNodeType {
		ENTRY, EXIT, LOOP, CALL, RETURN
	};

	private final String className;
	private final ClassCallGraph ccg;
	private final ClassLoader classLoader;
	

	private Map methodEntries = new HashMap();
	private Map methodExits = new HashMap();

	public Set publicMethods = new HashSet();

	private Map frameNodes = new HashMap();

	// cache of already analyzed methods that are known to be pure or impure
	// respectively
	private Set pureMethods = new HashSet();
	private Set impureMethods = new HashSet();

	// auxilary set for purity analysis to keep track of methods that are
	// currently
	// being analyzed across several CCFGs. elements are of the form
	// .
	private static Set methodsInPurityAnalysis = new HashSet();


	/**
	 * Given the ClassCallGraph of a class this constructor will build up the
	 * corresponding CCFG using the RCFGs from the GraphPool.
	 * 
	 * @param ccg
	 *            a {@link org.evosuite.graphs.ccg.ClassCallGraph} object.
	 */
	public ClassControlFlowGraph(ClassCallGraph ccg) {
		super(CCFGEdge.class);
		this.className = ccg.getClassName();
		this.ccg = ccg;
		this.classLoader = ccg.getClassLoader();
		nicenDotOutput();
		compute();
	}





	// purity analysis

	public boolean isPure(String methodName) {
		if (pureMethods.contains(methodName))
			return true;
		else if (impureMethods.contains(methodName))
			return false;

		boolean isPure = analyzePurity(methodName);
		if (isPure) {
			pureMethods.add(methodName);
			return true;
		} else {
			impureMethods.add(methodName);
			return false;
		}
	}

	private boolean analyzePurity(String methodName) {

		if (!methodEntries.containsKey(methodName)) {
			// workaround to deal with abstract methods for now
			// default behaviour for unknown things is "pure" for now
			return true;
		}

		CCFGMethodEntryNode entry = getMethodEntryOf(methodName);
		Set handled = new HashSet();

		// LoggingUtils.getEvoLogger().info(
		// "Starting purity analysis of " + methodName);

		// add methodName to set of currently analyzed methods
		methodsInPurityAnalysis.add(className + "." + methodName);
		boolean r = analyzePurity(methodName, entry, handled);
		// remove methodName from set of currently analyzed methods
		methodsInPurityAnalysis.remove(className + "." + methodName);

		return r;
	}

	private boolean analyzePurity(String analyzedMethod, CCFGNode currentNode,
			Set handled) {

		if (handled.contains(currentNode)) {
			// if we already handled the node we know it is pure otherwise we
			// would have returned
			return true;
		}
		handled.add(currentNode);

		// the node at which analysis is supposed to continue
		// used for skipping intermediate nodes for CCFGMethodCallNodes
		CCFGNode nextNode = currentNode;
		
		if (currentNode instanceof CCFGFieldClassCallNode) {
			CCFGFieldClassCallNode fieldCall = (CCFGFieldClassCallNode) currentNode;
			// TODO for now we will have to ignore classes that we are not able
			// to analyze.
			// this should only happen for classes in java.*
			String toAnalyze = fieldCall.getClassName() + "."
					+ fieldCall.getMethodName();
			if (GraphPool.getInstance(classLoader).canMakeCCFGForClass(fieldCall.getClassName())) {
				
				if (!methodsInPurityAnalysis.contains(toAnalyze)) {
					ClassControlFlowGraph ccfg = GraphPool.getInstance(classLoader).getCCFG(fieldCall
							.getClassName());
					if (!ccfg.isPure(fieldCall.getMethodName())) {
						// if fieldCall is impure this method is also impure
						return false;
					}
				}
			}
			
			else{

				//The format that ASM for types and the one used in my data file is different: in particular ASM uses the 
				//Class.getName format for types see http://docs.oracle.com/javase/6/docs/api/java/lang/Class.html#getName(), while the data
				//file with the pure methods uses the qualified name. 
				//For instance, in my file is: java.blabla.ClassExample.method(java.util.List,java.lang.Class[])
				//ASM returns java.blabla.ClassExample.method(Ljava.util.List;[Ljava.lang.Class)V.
				//The conversion from qualified name to the JVM/ASM format is not so straightforward, 
				//well it's not a very complicate problem but there some corner cases that I have to check. 
				//In the mean time this method convert the ASM/JVM format into the normal one, using an utility 
				//of ASM.
				//The file with the method list is in src/resources, it SHOULD be accurate but not perfect, some methods are missing for sure.
				
				if(toAnalyze.startsWith("java.")){
					 
					Type[] parameters = org.objectweb.asm.Type.getArgumentTypes(fieldCall.getOnlyParameters());
					String newParams = "";
					if(parameters.length!=0){
						for (Type i : parameters) {
							newParams = newParams + "," + i.getClassName();
						}
						newParams = newParams.substring(1, newParams.length());
					}
					toAnalyze=fieldCall.getClassName() + "." + fieldCall.getOnlyMethodName()+"("+newParams+")";
					
					return JdkPureMethodsList.instance.checkPurity(toAnalyze);
				}
			}
			
			// otherwise proceed
		} else if (currentNode instanceof CCFGCodeNode) {
			CCFGCodeNode codeNode = (CCFGCodeNode) currentNode;
			// it this node alters the state of this object this method is
			// impure
			if (codeNode.getCodeInstruction().isFieldDefinition())
				return false;
			// otherwise proceed
		} else if (currentNode instanceof CCFGMethodExitNode) {
			CCFGMethodExitNode methodExit = (CCFGMethodExitNode) currentNode;
			// if we encounter the end of the analyzed method and have not
			// detected
			// impurity yet then the method is pure
			if (methodExit.getMethod().equals(analyzedMethod))
				return true;
			else
				throw new IllegalStateException(
						"MethodExitNodes from methods other then the currently analyzed one should not be reached");
		} else if (currentNode instanceof CCFGMethodCallNode) {
			CCFGMethodCallNode callNode = (CCFGMethodCallNode) currentNode;
			// avoid loops in analysis
			String toAnalyze = className + "." + callNode.getCalledMethod();
			if (!methodsInPurityAnalysis.contains(toAnalyze)) {
				// if another method of this class is called check that
				// method
				// it the called method is impure then this method is impure
				if (!isPure(callNode.getCalledMethod()))
					return false;
			}
			// otherwise proceed after the method call has taken place
			nextNode = callNode.getReturnNode();
		} else if (currentNode instanceof CCFGMethodEntryNode) {
			// do nothing special
		} else
			throw new IllegalStateException(
					"purity analysis should not reach this kind of CCFGNode: "
							+ currentNode.getClass().toString());

		Set children = getChildren(nextNode);
		for (CCFGNode child : children) {
			if (!analyzePurity(analyzedMethod, child, handled))
				return false;
		}

		// no child was impure so this method is pure
		return true;
	}

	// sanity functions


	public boolean isPublicMethod(String method) {
		if (method == null)
			return false;
		CCFGMethodEntryNode entry = getMethodEntryOf(method);
		return isPublicMethod(entry);
	}

	public boolean isPublicMethod(CCFGMethodEntryNode node) {
		if (node == null)
			return false;
		return publicMethods.contains(node);
	}


	// convenience getters

	public CCFGMethodEntryNode getMethodEntryNodeForClassCallNode(
			ClassCallNode ccgNode) {
		CCFGMethodEntryNode r = methodEntries.get(ccgNode.getMethod());
		if (r == null)
			throw new IllegalStateException(
					"expect the CCFG to contain a CCFGMethodEntryNode for each node in the corresponding CCG "
							+ ccgNode.getMethod());
		return r;
	}

	private CCFGMethodEntryNode getMethodEntryOf(String method) {
		CCFGMethodEntryNode r = methodEntries.get(method);
		if (r == null)
			throw new IllegalArgumentException("unknown method: " + method);
		return r;

	}

	private RawControlFlowGraph getRCFG(ClassCallNode ccgNode) {
		return GraphPool.getInstance(classLoader).getRawCFG(className, ccgNode.getMethod());
	}

	/**
	 * 

* getMethodExitOf *

* * @param methodEntry * a {@link org.evosuite.graphs.ccfg.CCFGMethodEntryNode} object. * @return a {@link org.evosuite.graphs.ccfg.CCFGMethodExitNode} object. */ public CCFGMethodExitNode getMethodExitOf(CCFGMethodEntryNode methodEntry) { if (methodEntry == null) return null; return methodExits.get(methodEntry.getMethod()); } /** *

* getMethodEntryOf *

* * @param methodExit * a {@link org.evosuite.graphs.ccfg.CCFGMethodExitNode} object. * @return a {@link org.evosuite.graphs.ccfg.CCFGMethodEntryNode} object. */ public CCFGMethodEntryNode getMethodEntryOf(CCFGMethodExitNode methodExit) { if (methodExit == null) return null; return methodEntries.get(methodExit.getMethod()); } // CCFG computation from CCG and CFGs private void compute() { importCFGs(); addFrame(); } private void importCFGs() { Map> tempMap = new HashMap>(); // replace each class call node with corresponding CFG for (ClassCallNode ccgNode : ccg.vertexSet()) { RawControlFlowGraph cfg = getRCFG(ccgNode); tempMap.put(cfg, importCFG(cfg)); } connectCFGs(tempMap); } private void connectCFGs( Map> tempMap) { for (RawControlFlowGraph cfg : tempMap.keySet()) { List calls = cfg .determineMethodCallsToOwnClass(); for (BytecodeInstruction call : calls) { // we do not want to connect every method call to the target // class, but only those that are called on the same object or // are static if (!(call.isCallToStaticMethod() || call .isMethodCallOnSameObject())) { // call.printFrameInformation(); continue; } connectCFG(cfg, call, tempMap); } } } private void connectCFG( RawControlFlowGraph cfg, BytecodeInstruction call, Map> tempMap) { // add MethodCallNode and MethodReturnNode CCFGMethodReturnNode returnNode = new CCFGMethodReturnNode(call); CCFGMethodCallNode callNode = new CCFGMethodCallNode(call, returnNode); addVertex(callNode); addVertex(returnNode); // connect with method entry and exit nodes of called method CCFGNode calleeEntry = methodEntries.get(call.getCalledMethod()); CCFGNode calleeExit = methodExits.get(call.getCalledMethod()); CCFGMethodCallEdge callEdge = new CCFGMethodCallEdge(call, true); CCFGMethodCallEdge returnEdge = new CCFGMethodCallEdge(call, false); addEdge(callNode, calleeEntry, callEdge); addEdge(calleeExit, returnNode, returnEdge); // redirect edges from the original CodeNode to the new nodes CCFGNode origCallNode = tempMap.get(cfg).get(call); if (!redirectEdges(origCallNode, callNode, returnNode) || !graph.removeVertex(origCallNode)) throw new IllegalStateException( "internal error while connecting cfgs during CCFG construction"); } private Map importCFG( RawControlFlowGraph cfg) { Map temp = new HashMap(); importCFGNodes(cfg, temp); importCFGEdges(cfg, temp); // enclose with CCFGMethodEntryNode and CCFGMethodExitNode encloseCFG(cfg, temp); return temp; } /** * import CFGs nodes. If the node is a method call to a method of a field * class, a new CCFGFieldClassCallNode is created. Otherwise, a normal * CCFGCodeNode is created * * @param cfg * @param temp */ private void importCFGNodes(RawControlFlowGraph cfg, Map temp) { // add BytecodeInstructions as CCFGCodeNodes for (BytecodeInstruction code : cfg.vertexSet()) { CCFGCodeNode node; if (code.isMethodCallOfField()) { node = new CCFGFieldClassCallNode(code, code.getCalledMethodsClass(), code.getCalledMethodName(), code.getMethodCallDescriptor()); } else { node = new CCFGCodeNode(code); } addVertex(node); temp.put(code, node); } } private void importCFGEdges(RawControlFlowGraph cfg, Map temp) { // add ControlFlowEdges as CCFGCodeEdges for (ControlFlowEdge e : cfg.edgeSet()) { if (e.isExceptionEdge()) continue; CCFGCodeNode src = temp.get(cfg.getEdgeSource(e)); CCFGCodeNode target = temp.get(cfg.getEdgeTarget(e)); addEdge(src, target, new CCFGCodeEdge(e)); } } private void encloseCFG(RawControlFlowGraph cfg, Map temp) { addCCFGMethodEntryNode(cfg, temp); addCCFGMethodExitNode(cfg, temp); } private CCFGMethodEntryNode addCCFGMethodEntryNode(RawControlFlowGraph cfg, Map temp) { CCFGCodeNode entryInstruction = temp.get(cfg.determineEntryPoint()); CCFGMethodEntryNode entry = new CCFGMethodEntryNode( cfg.getMethodName(), entryInstruction); addVertex(entry); addEdge(entry, entryInstruction); methodEntries.put(cfg.getMethodName(), entry); return entry; } private CCFGMethodExitNode addCCFGMethodExitNode(RawControlFlowGraph cfg, Map temp) { CCFGMethodExitNode exit = new CCFGMethodExitNode(cfg.getMethodName()); addVertex(exit); for (BytecodeInstruction exitPoint : cfg.determineExitPoints()) { addEdge(temp.get(exitPoint), exit); } methodExits.put(cfg.getMethodName(), exit); return exit; } private void addFrame() { addFrameNodes(); addFrameEdges(); connectPublicMethodsToFrame(); } private void addFrameNodes() { for (FrameNodeType type : FrameNodeType.values()) { CCFGFrameNode node = new CCFGFrameNode(type); addVertex(node); frameNodes.put(type, node); } } private void addFrameEdges() { addEdge(getFrameNode(FrameNodeType.ENTRY), getFrameNode(FrameNodeType.LOOP), new CCFGFrameEdge()); addEdge(getFrameNode(FrameNodeType.LOOP), getFrameNode(FrameNodeType.CALL), new CCFGFrameEdge()); addEdge(getFrameNode(FrameNodeType.LOOP), getFrameNode(FrameNodeType.EXIT), new CCFGFrameEdge()); addEdge(getFrameNode(FrameNodeType.RETURN), getFrameNode(FrameNodeType.LOOP), new CCFGFrameEdge()); } /** *

* getFrameNode *

* * @param type * a * {@link org.evosuite.graphs.ccfg.ClassControlFlowGraph.FrameNodeType} * object. * @return a {@link org.evosuite.graphs.ccfg.CCFGFrameNode} object. */ public CCFGFrameNode getFrameNode(FrameNodeType type) { return frameNodes.get(type); } /** * Adds a CCFGFrameEdge from the CCFGFrameNode CALL to the * CCFGMethodEntryNode of each public method and from their * CCFGMethodExitNode to the CCFGFrameNode RETURN. */ private void connectPublicMethodsToFrame() { for (ClassCallNode ccgNode : ccg.vertexSet()) { RawControlFlowGraph cfg = getRCFG(ccgNode); if (cfg.isPublicMethod()) { addEdge(getFrameNode(FrameNodeType.CALL), methodEntries.get(ccgNode.getMethod()), new CCFGFrameEdge()); addEdge(methodExits.get(ccgNode.getMethod()), getFrameNode(FrameNodeType.RETURN), new CCFGFrameEdge()); publicMethods.add(methodEntries.get(ccgNode.getMethod())); } } } // toDot utilities /** * Makes .dot output pretty by visualizing different types of nodes and * edges with different forms and colors */ private void nicenDotOutput() { registerVertexAttributeProvider(new CCFGNodeAttributeProvider()); registerEdgeAttributeProvider(new CCFGEdgeAttributeProvider()); } /** {@inheritDoc} */ @Override public String getName() { return "CCFG_" + className; } /** {@inheritDoc} */ @Override protected String dotSubFolder() { return toFileString(className) + "/"; } /** * @return the ccg */ public ClassCallGraph getCcg() { return ccg; } }




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