Java LocalUses類代碼示例

import soot.toolkits.scalar.LocalUses; //導入依賴的package包/類
/**
 * Collect definitions of l in body including the definitions of aliases of
 * l.
 * 
 * In this context an alias is a local that propagates its value to l.
 * 
 * @param l
 *            the local whose definitions are to collect
 * @param localDefs
 *            the LocalDefs object
 * @param body
 *            the body that contains the local
 */
protected List<Unit> collectDefinitionsWithAliases(Local l,
		LocalDefs localDefs, LocalUses localUses, Body body) {
	Set<Local> seenLocals = new HashSet<Local>();
	Stack<Local> newLocals = new Stack<Local>();
	List<Unit> defs = new LinkedList<Unit>();
	newLocals.push(l);

	while (!newLocals.empty()) {
		Local local = newLocals.pop();
		Debug.printDbg("[null local] ", local);
		if (!seenLocals.add(local))
			continue;
		for (Unit u : collectDefinitions(local, localDefs, body)) {
			if (u instanceof AssignStmt) {
				Value r = ((AssignStmt) u).getRightOp();
				if (r instanceof Local && !seenLocals.contains((Local) r))
					newLocals.push((Local) r);
			}
			defs.add(u);
			//
			List<UnitValueBoxPair> usesOf = (List<UnitValueBoxPair>) localUses
					.getUsesOf(u);
			for (UnitValueBoxPair pair : usesOf) {
				Unit unit = pair.getUnit();
				if (unit instanceof AssignStmt) {
					Value right = ((AssignStmt) unit).getRightOp();
					Value left = ((AssignStmt) unit).getLeftOp();
					if (right == local && left instanceof Local
							&& !seenLocals.contains((Local) left))
						newLocals.push((Local) left);
				}
			}
			//
		}
	}
	return defs;
}
 

import soot.toolkits.scalar.LocalUses; //導入依賴的package包/類
/** This method change all new Obj/<init>(args) pairs to new Obj(args) idioms. */
protected void internalTransform(Body b, String phaseName, Map options)
{
    GrimpBody body = (GrimpBody)b;

    if(Options.v().verbose())
        G.v().out.println("[" + body.getMethod().getName() +
            "] Folding constructors...");

  Chain units = body.getUnits();
  List<Unit> stmtList = new ArrayList<Unit>();
  stmtList.addAll(units);

  Iterator<Unit> it = stmtList.iterator();
  
  LocalUses localUses = LocalUses.Factory.newLocalUses(b);

  /* fold in NewExpr's with specialinvoke's */
  while (it.hasNext())
    {
      Stmt s = (Stmt)it.next();
        
      if (!(s instanceof AssignStmt))
        continue;
        
      /* this should be generalized to ArrayRefs */
      Value lhs = ((AssignStmt)s).getLeftOp();
      if (!(lhs instanceof Local))
        continue;
        
      Value rhs = ((AssignStmt)s).getRightOp();
      if (!(rhs instanceof NewExpr))
        continue;

      /* TO BE IMPLEMENTED LATER: move any copy of the object reference
         for lhs down beyond the NewInvokeExpr, with the rationale
         being that you can't modify the object before the constructor
         call in any case.

         Also, do note that any new's (object creation) without
         corresponding constructors must be dead. */
       
      List lu = localUses.getUsesOf(s);
      Iterator luIter = lu.iterator();
      boolean MadeNewInvokeExpr = false;
       
      while (luIter.hasNext())
        {
          Unit use = ((UnitValueBoxPair)(luIter.next())).unit;
          if (!(use instanceof InvokeStmt))
            continue;
          InvokeStmt is = (InvokeStmt)use;
          if (!(is.getInvokeExpr() instanceof SpecialInvokeExpr) ||
              lhs != ((SpecialInvokeExpr)is.getInvokeExpr()).getBase())
            continue;
          
          SpecialInvokeExpr oldInvoke = 
            ((SpecialInvokeExpr)is.getInvokeExpr());
          LinkedList invokeArgs = new LinkedList();
          for (int i = 0; i < oldInvoke.getArgCount(); i++)
            invokeArgs.add(oldInvoke.getArg(i));
          
          AssignStmt constructStmt = Grimp.v().newAssignStmt
            ((AssignStmt)s);
          constructStmt.setRightOp
            (Grimp.v().newNewInvokeExpr
             (((NewExpr)rhs).getBaseType(), oldInvoke.getMethodRef(), invokeArgs));
          MadeNewInvokeExpr = true;
          
          use.redirectJumpsToThisTo(constructStmt);
          units.insertBefore(constructStmt, use);
          units.remove(use);
        }
      if (MadeNewInvokeExpr)
        {
          units.remove(s);
        }
    }
}
 

import soot.toolkits.scalar.LocalUses; //導入依賴的package包/類
@Override
protected void internalTransform(Body body, String phaseName, Map<String, String> options) {
       ExceptionalUnitGraph graph = new ExceptionalUnitGraph(body, DalvikThrowAnalysis.v(), true);
       LocalDefs localDefs = LocalDefs.Factory.newLocalDefs(graph);
       LocalUses localUses = null;
       LocalCreation localCreation = null;
       
	// If a return statement's operand has only one definition and this is
	// a copy statement, we take the original operand
	for (Unit u : body.getUnits())
		if (u instanceof ReturnStmt) {
			ReturnStmt retStmt = (ReturnStmt) u;
			if (retStmt.getOp() instanceof Local) {
				List<Unit> defs = localDefs.getDefsOfAt((Local) retStmt.getOp(), retStmt);
				if (defs.size() == 1 && defs.get(0) instanceof AssignStmt) {
					AssignStmt assign = (AssignStmt) defs.get(0);
					final Value rightOp = assign.getRightOp();
					final Value leftOp = assign.getLeftOp();
					
					// Copy over the left side if it is a local
					if (rightOp instanceof Local) {
						// We must make sure that the definition we propagate to
						// the return statement is not overwritten in between
						// a = 1; b = a; a = 3; return b; may not be translated
						// to return a;
						if (!isRedefined((Local) rightOp, u, assign, graph))
							retStmt.setOp(rightOp);
					}
					else if (rightOp instanceof Constant) {
						retStmt.setOp(rightOp);
					}
					// If this is a field access which has no other uses,
					// we rename the local to help splitting
					else if (rightOp instanceof FieldRef) {
						if (localUses == null)
							localUses = LocalUses.Factory.newLocalUses(body, localDefs);
						if (localUses.getUsesOf(assign).size() == 1) {
							if (localCreation == null)
								localCreation = new LocalCreation(body.getLocals(), "ret");
							Local newLocal = localCreation.newLocal(leftOp.getType());
							assign.setLeftOp(newLocal);
							retStmt.setOp(newLocal);
						}
					}
				}
			}
		}
}