/** * This method pushes all newExpr down to be the stmt directly before every invoke of the init * only if they are in the types list */ public void internalTransform(Body b, String phaseName, Map options) { JimpleBody body = (JimpleBody) b; if (Options.v().verbose()) G.v().out.println("[" + body.getMethod().getName() + "] Folding Jimple constructors..."); Chain units = body.getUnits(); List<Unit> stmtList = new ArrayList<Unit>(); stmtList.addAll(units); Iterator<Unit> it = stmtList.iterator(); Iterator<Unit> nextStmtIt = stmtList.iterator(); // start ahead one nextStmtIt.next(); SmartLocalDefs localDefs = SmartLocalDefsPool.v().getSmartLocalDefsFor(body); UnitGraph graph = localDefs.getGraph(); LocalUses localUses = new SimpleLocalUses(graph, localDefs); /* 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 */ // only deal with stmts that are an local = newExpr Value lhs = ((AssignStmt) s).getLeftOp(); if (!(lhs instanceof Local)) continue; Value rhs = ((AssignStmt) s).getRightOp(); if (!(rhs instanceof NewExpr)) continue; // check if very next statement is invoke --> // this indicates there is no control flow between // new and invoke and should do nothing if (nextStmtIt.hasNext()) { Stmt next = (Stmt) nextStmtIt.next(); if (next instanceof InvokeStmt) { InvokeStmt invoke = (InvokeStmt) next; if (invoke.getInvokeExpr() instanceof SpecialInvokeExpr) { SpecialInvokeExpr invokeExpr = (SpecialInvokeExpr) invoke.getInvokeExpr(); if (invokeExpr.getBase() == lhs) { break; } } } } // check if new is in the types list - only process these if (!types.contains(((NewExpr) rhs).getType())) continue; 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; // make a new one here AssignStmt constructStmt = Jimple.v() .newAssignStmt(((DefinitionStmt) s).getLeftOp(), ((DefinitionStmt) s).getRightOp()); constructStmt.setRightOp(Jimple.v().newNewExpr(((NewExpr) rhs).getBaseType())); MadeNewInvokeExpr = true; // redirect jumps use.redirectJumpsToThisTo(constructStmt); // insert new one here units.insertBefore(constructStmt, use); constructStmt.addTag(s.getTag("SourceLnPosTag")); } if (MadeNewInvokeExpr) { units.remove(s); } } }
private static boolean internalAggregate( StmtBody body, Map<ValueBox, Zone> boxToZone, boolean onlyStackVars) { LocalUses localUses; LocalDefs localDefs; ExceptionalUnitGraph graph; boolean hadAggregation = false; Chain<Unit> units = body.getUnits(); graph = new ExceptionalUnitGraph(body); localDefs = new SmartLocalDefs(graph, new SimpleLiveLocals(graph)); localUses = new SimpleLocalUses(graph, localDefs); List<Unit> unitList = new PseudoTopologicalOrderer<Unit>().newList(graph, false); for (Unit u : unitList) { if (!(u instanceof AssignStmt)) continue; AssignStmt s = (AssignStmt) u; Value lhs = s.getLeftOp(); if (!(lhs instanceof Local)) continue; Local lhsLocal = (Local) lhs; if (onlyStackVars && !lhsLocal.getName().startsWith("$")) continue; List<UnitValueBoxPair> lu = localUses.getUsesOf(s); if (lu.size() != 1) continue; UnitValueBoxPair usepair = lu.get(0); Unit use = usepair.unit; ValueBox useBox = usepair.valueBox; List<Unit> ld = localDefs.getDefsOfAt(lhsLocal, use); if (ld.size() != 1) continue; // Check to make sure aggregation pair in the same zone if (boxToZone.get(s.getRightOpBox()) != boxToZone.get(usepair.valueBox)) { continue; } /* we need to check the path between def and use */ /* to see if there are any intervening re-defs of RHS */ /* in fact, we should check that this path is unique. */ /* if the RHS uses only locals, then we know what to do; if RHS has a method invocation f(a, b, c) or field access, we must ban field writes, other method calls and (as usual) writes to a, b, c. */ boolean cantAggr = false; boolean propagatingInvokeExpr = false; boolean propagatingFieldRef = false; boolean propagatingArrayRef = false; ArrayList<FieldRef> fieldRefList = new ArrayList<FieldRef>(); LinkedList<Value> localsUsed = new LinkedList<Value>(); for (ValueBox vb : s.getUseBoxes()) { Value v = vb.getValue(); if (v instanceof Local) localsUsed.add(v); else if (v instanceof InvokeExpr) propagatingInvokeExpr = true; else if (v instanceof ArrayRef) propagatingArrayRef = true; else if (v instanceof FieldRef) { propagatingFieldRef = true; fieldRefList.add((FieldRef) v); } } // look for a path from s to use in graph. // only look in an extended basic block, though. List<Unit> path = graph.getExtendedBasicBlockPathBetween(s, use); if (path == null) continue; Iterator<Unit> pathIt = path.iterator(); // skip s. if (pathIt.hasNext()) pathIt.next(); while (pathIt.hasNext() && !cantAggr) { Stmt between = (Stmt) (pathIt.next()); if (between != use) { // Check for killing definitions for (ValueBox vb : between.getDefBoxes()) { Value v = vb.getValue(); if (localsUsed.contains(v)) { cantAggr = true; break; } if (propagatingInvokeExpr || propagatingFieldRef || propagatingArrayRef) { if (v instanceof FieldRef) { if (propagatingInvokeExpr) { cantAggr = true; break; } else if (propagatingFieldRef) { // Can't aggregate a field access if passing a definition of a field // with the same name, because they might be aliased for (FieldRef fieldRef : fieldRefList) { if (((FieldRef) v).getField() == fieldRef.getField()) { cantAggr = true; break; } } } } else if (v instanceof ArrayRef) { if (propagatingInvokeExpr) { // Cannot aggregate an invoke expr past an array write cantAggr = true; break; } else if (propagatingArrayRef) { // cannot aggregate an array read past a write // this is somewhat conservative // (if types differ they may not be aliased) cantAggr = true; break; } } } } // Make sure not propagating past a {enter,exit}Monitor if (propagatingInvokeExpr && between instanceof MonitorStmt) cantAggr = true; } // Check for intervening side effects due to method calls if (propagatingInvokeExpr || propagatingFieldRef || propagatingArrayRef) { for (final ValueBox box : between.getUseBoxes()) { if (between == use && box == useBox) { // Reached use point, stop looking for // side effects break; } Value v = box.getValue(); if (v instanceof InvokeExpr || (propagatingInvokeExpr && (v instanceof FieldRef || v instanceof ArrayRef))) { cantAggr = true; break; } } } } // we give up: can't aggregate. if (cantAggr) { continue; } /* assuming that the d-u chains are correct, */ /* we need not check the actual contents of ld */ Value aggregatee = s.getRightOp(); if (usepair.valueBox.canContainValue(aggregatee)) { boolean wasSimpleCopy = isSimpleCopy(usepair.unit); usepair.valueBox.setValue(aggregatee); units.remove(s); hadAggregation = true; // clean up the tags. If s was not a simple copy, the new statement should get // the tags of s. // OK, this fix was wrong. The condition should not be // "If s was not a simple copy", but rather "If usepair.unit // was a simple copy". This way, when there's a load of a constant // followed by an invoke, the invoke gets the tags. if (wasSimpleCopy) { // usepair.unit.removeAllTags(); usepair.unit.addAllTagsOf(s); } } else { /* if(Options.v().verbose()) { G.v().out.println("[debug] failed aggregation"); G.v().out.println("[debug] tried to put "+aggregatee+ " into "+usepair.stmt + ": in particular, "+usepair.valueBox); G.v().out.println("[debug] aggregatee instanceof Expr: " +(aggregatee instanceof Expr)); }*/ } } return hadAggregation; }