use of soot.jimple.IfStmt in project soot by Sable.
the class DexNullTransformer method internalTransform.
@Override
protected void internalTransform(final Body body, String phaseName, Map<String, String> options) {
final DexDefUseAnalysis localDefs = new DexDefUseAnalysis(body);
AbstractStmtSwitch checkDef = new // Alex: should also end as
AbstractStmtSwitch() {
// soon as detected as not
// used as an object
@Override
public void caseAssignStmt(AssignStmt stmt) {
Value r = stmt.getRightOp();
if (r instanceof FieldRef) {
usedAsObject = isObject(((FieldRef) r).getFieldRef().type());
doBreak = true;
return;
} else if (r instanceof ArrayRef) {
ArrayRef ar = (ArrayRef) r;
if (ar.getType() instanceof UnknownType) {
// isObject
usedAsObject = stmt.hasTag("ObjectOpTag");
// (findArrayType
// (g,
// localDefs,
// localUses,
// stmt));
} else {
usedAsObject = isObject(ar.getType());
}
doBreak = true;
return;
} else if (r instanceof StringConstant || r instanceof NewExpr || r instanceof NewArrayExpr) {
usedAsObject = true;
doBreak = true;
return;
} else if (r instanceof CastExpr) {
usedAsObject = isObject(((CastExpr) r).getCastType());
doBreak = true;
return;
} else if (r instanceof InvokeExpr) {
usedAsObject = isObject(((InvokeExpr) r).getType());
doBreak = true;
return;
} else if (r instanceof LengthExpr) {
usedAsObject = false;
doBreak = true;
return;
// introduces alias
}
}
@Override
public void caseIdentityStmt(IdentityStmt stmt) {
if (stmt.getLeftOp() == l) {
usedAsObject = isObject(stmt.getRightOp().getType());
doBreak = true;
return;
}
}
};
AbstractStmtSwitch checkUse = new AbstractStmtSwitch() {
private boolean examineInvokeExpr(InvokeExpr e) {
List<Value> args = e.getArgs();
List<Type> argTypes = e.getMethodRef().parameterTypes();
assert args.size() == argTypes.size();
for (int i = 0; i < args.size(); i++) {
if (args.get(i) == l && isObject(argTypes.get(i))) {
return true;
}
}
// check for base
SootMethodRef sm = e.getMethodRef();
if (!sm.isStatic()) {
if (e instanceof AbstractInvokeExpr) {
AbstractInstanceInvokeExpr aiiexpr = (AbstractInstanceInvokeExpr) e;
Value b = aiiexpr.getBase();
if (b == l) {
return true;
}
}
}
return false;
}
@Override
public void caseInvokeStmt(InvokeStmt stmt) {
InvokeExpr e = stmt.getInvokeExpr();
usedAsObject = examineInvokeExpr(e);
doBreak = true;
return;
}
@Override
public void caseAssignStmt(AssignStmt stmt) {
Value left = stmt.getLeftOp();
Value r = stmt.getRightOp();
if (left instanceof ArrayRef) {
ArrayRef ar = (ArrayRef) left;
if (ar.getIndex() == l) {
doBreak = true;
return;
} else if (ar.getBase() == l) {
usedAsObject = true;
doBreak = true;
return;
}
}
if (left instanceof InstanceFieldRef) {
InstanceFieldRef ifr = (InstanceFieldRef) left;
if (ifr.getBase() == l) {
usedAsObject = true;
doBreak = true;
return;
}
}
// used to assign
if (stmt.getRightOp() == l) {
Value l = stmt.getLeftOp();
if (l instanceof StaticFieldRef && isObject(((StaticFieldRef) l).getFieldRef().type())) {
usedAsObject = true;
doBreak = true;
return;
} else if (l instanceof InstanceFieldRef && isObject(((InstanceFieldRef) l).getFieldRef().type())) {
usedAsObject = true;
doBreak = true;
return;
} else if (l instanceof ArrayRef) {
Type aType = ((ArrayRef) l).getType();
if (aType instanceof UnknownType) {
usedAsObject = stmt.hasTag(// isObject(
"ObjectOpTag");
// findArrayType(g,
// localDefs,
// localUses,
// stmt));
} else {
usedAsObject = isObject(aType);
}
doBreak = true;
return;
}
}
// is used as value (does not exclude assignment)
if (r instanceof FieldRef) {
// isObject(((FieldRef)
usedAsObject = true;
// r).getFieldRef().type());
doBreak = true;
return;
} else if (r instanceof ArrayRef) {
ArrayRef ar = (ArrayRef) r;
if (ar.getBase() == l) {
usedAsObject = true;
} else {
// used as index
usedAsObject = false;
}
doBreak = true;
return;
} else if (r instanceof StringConstant || r instanceof NewExpr) {
throw new RuntimeException("NOT POSSIBLE StringConstant or NewExpr at " + stmt);
} else if (r instanceof NewArrayExpr) {
usedAsObject = false;
doBreak = true;
return;
} else if (r instanceof CastExpr) {
usedAsObject = isObject(((CastExpr) r).getCastType());
doBreak = true;
return;
} else if (r instanceof InvokeExpr) {
usedAsObject = examineInvokeExpr((InvokeExpr) stmt.getRightOp());
doBreak = true;
return;
} else if (r instanceof LengthExpr) {
usedAsObject = true;
doBreak = true;
return;
} else if (r instanceof BinopExpr) {
usedAsObject = false;
doBreak = true;
return;
}
}
@Override
public void caseIdentityStmt(IdentityStmt stmt) {
if (stmt.getLeftOp() == l)
throw new RuntimeException("IMPOSSIBLE 0");
}
@Override
public void caseEnterMonitorStmt(EnterMonitorStmt stmt) {
usedAsObject = stmt.getOp() == l;
doBreak = true;
return;
}
@Override
public void caseExitMonitorStmt(ExitMonitorStmt stmt) {
usedAsObject = stmt.getOp() == l;
doBreak = true;
return;
}
@Override
public void caseReturnStmt(ReturnStmt stmt) {
usedAsObject = stmt.getOp() == l && isObject(body.getMethod().getReturnType());
doBreak = true;
return;
}
@Override
public void caseThrowStmt(ThrowStmt stmt) {
usedAsObject = stmt.getOp() == l;
doBreak = true;
return;
}
};
for (Local loc : getNullCandidates(body)) {
usedAsObject = false;
Set<Unit> defs = localDefs.collectDefinitionsWithAliases(loc);
// process normally
doBreak = false;
for (Unit u : defs) {
// put correct local in l
if (u instanceof DefinitionStmt) {
l = (Local) ((DefinitionStmt) u).getLeftOp();
} else if (u instanceof IfStmt) {
throw new RuntimeException("ERROR: def can not be something else than Assign or Identity statement! (def: " + u + " class: " + u.getClass() + "");
}
// check defs
u.apply(checkDef);
if (doBreak)
break;
// check uses
for (Unit use : localDefs.getUsesOf(l)) {
use.apply(checkUse);
if (doBreak)
break;
}
// for uses
if (doBreak)
break;
}
// change values
if (usedAsObject) {
for (Unit u : defs) {
replaceWithNull(u);
Set<Value> defLocals = new HashSet<Value>();
for (ValueBox vb : u.getDefBoxes()) defLocals.add(vb.getValue());
Local l = (Local) ((DefinitionStmt) u).getLeftOp();
for (Unit uuse : localDefs.getUsesOf(l)) {
Stmt use = (Stmt) uuse;
// If we have a[x] = 0 and a is an object, we may not conclude 0 -> null
if (!use.containsArrayRef() || !defLocals.contains(use.getArrayRef().getBase()))
replaceWithNull(use);
}
}
}
// end if
}
// Check for inlined zero values
AbstractStmtSwitch inlinedZeroValues = new AbstractStmtSwitch() {
final NullConstant nullConstant = NullConstant.v();
@Override
public void caseAssignStmt(AssignStmt stmt) {
// Case a = 0 with a being an object
if (isObject(stmt.getLeftOp().getType()) && isConstZero(stmt.getRightOp())) {
stmt.setRightOp(nullConstant);
return;
}
// Case a = (Object) 0
if (stmt.getRightOp() instanceof CastExpr) {
CastExpr ce = (CastExpr) stmt.getRightOp();
if (isObject(ce.getCastType()) && isConstZero(ce.getOp())) {
stmt.setRightOp(nullConstant);
}
}
// Case a[0] = 0
if (stmt.getLeftOp() instanceof ArrayRef && isConstZero(stmt.getRightOp())) {
ArrayRef ar = (ArrayRef) stmt.getLeftOp();
if (isObjectArray(ar.getBase(), body) || stmt.hasTag("ObjectOpTag")) {
stmt.setRightOp(nullConstant);
}
}
}
private boolean isConstZero(Value rightOp) {
if (rightOp instanceof IntConstant && ((IntConstant) rightOp).value == 0)
return true;
if (rightOp instanceof LongConstant && ((LongConstant) rightOp).value == 0)
return true;
return false;
}
@Override
public void caseReturnStmt(ReturnStmt stmt) {
if (stmt.getOp() instanceof IntConstant && isObject(body.getMethod().getReturnType())) {
IntConstant iconst = (IntConstant) stmt.getOp();
assert iconst.value == 0;
stmt.setOp(nullConstant);
}
}
@Override
public void caseEnterMonitorStmt(EnterMonitorStmt stmt) {
if (stmt.getOp() instanceof IntConstant && ((IntConstant) stmt.getOp()).value == 0)
stmt.setOp(nullConstant);
}
@Override
public void caseExitMonitorStmt(ExitMonitorStmt stmt) {
if (stmt.getOp() instanceof IntConstant && ((IntConstant) stmt.getOp()).value == 0)
stmt.setOp(nullConstant);
}
};
final NullConstant nullConstant = NullConstant.v();
for (Unit u : body.getUnits()) {
u.apply(inlinedZeroValues);
if (u instanceof Stmt) {
Stmt stmt = (Stmt) u;
if (stmt.containsInvokeExpr()) {
InvokeExpr invExpr = stmt.getInvokeExpr();
for (int i = 0; i < invExpr.getArgCount(); i++) if (isObject(invExpr.getMethodRef().parameterType(i)))
if (invExpr.getArg(i) instanceof IntConstant) {
IntConstant iconst = (IntConstant) invExpr.getArg(i);
assert iconst.value == 0;
invExpr.setArg(i, nullConstant);
}
}
}
}
}
use of soot.jimple.IfStmt in project soot by Sable.
the class DexNullTransformer method getNullCandidates.
/**
* Collect all the locals which are assigned a IntConstant(0) or are used
* within a zero comparison.
*
* @param body
* the body to analyze
*/
private Set<Local> getNullCandidates(Body body) {
Set<Local> candidates = null;
for (Unit u : body.getUnits()) {
if (u instanceof AssignStmt) {
AssignStmt a = (AssignStmt) u;
if (!(a.getLeftOp() instanceof Local))
continue;
Local l = (Local) a.getLeftOp();
Value r = a.getRightOp();
if ((r instanceof IntConstant && ((IntConstant) r).value == 0) || (r instanceof LongConstant && ((LongConstant) r).value == 0)) {
if (candidates == null)
candidates = new HashSet<Local>();
candidates.add(l);
}
} else if (u instanceof IfStmt) {
ConditionExpr expr = (ConditionExpr) ((IfStmt) u).getCondition();
if (isZeroComparison(expr) && expr.getOp1() instanceof Local) {
if (candidates == null)
candidates = new HashSet<Local>();
candidates.add((Local) expr.getOp1());
}
}
}
return candidates == null ? Collections.<Local>emptySet() : candidates;
}
use of soot.jimple.IfStmt in project soot by Sable.
the class DexReturnInliner method internalTransform.
@Override
protected void internalTransform(final Body body, String phaseName, Map<String, String> options) {
Set<Unit> duplicateIfTargets = getFallThroughReturns(body);
Iterator<Unit> it = body.getUnits().snapshotIterator();
boolean mayBeMore = false;
Unit last = null;
do {
mayBeMore = false;
while (it.hasNext()) {
Unit u = it.next();
if (u instanceof GotoStmt) {
GotoStmt gtStmt = (GotoStmt) u;
if (isInstanceofReturn(gtStmt.getTarget())) {
Stmt stmt = (Stmt) gtStmt.getTarget().clone();
for (Trap t : body.getTraps()) for (UnitBox ubox : t.getUnitBoxes()) if (ubox.getUnit() == u)
ubox.setUnit(stmt);
while (!u.getBoxesPointingToThis().isEmpty()) u.getBoxesPointingToThis().get(0).setUnit(stmt);
// the cloned return stmt gets the tags of u
stmt.addAllTagsOf(u);
body.getUnits().swapWith(u, stmt);
mayBeMore = true;
}
} else if (u instanceof IfStmt) {
IfStmt ifstmt = (IfStmt) u;
Unit t = ifstmt.getTarget();
if (isInstanceofReturn(t)) {
// once, otherwise we will end up with unused copies
if (duplicateIfTargets == null)
duplicateIfTargets = new HashSet<Unit>();
if (!duplicateIfTargets.add(t)) {
Unit newTarget = (Unit) t.clone();
body.getUnits().addLast(newTarget);
ifstmt.setTarget(newTarget);
}
}
} else if (isInstanceofReturn(u)) {
// the original return stmt gets the tags of its predecessor
if (last != null) {
u.removeAllTags();
u.addAllTagsOf(last);
}
}
last = u;
}
} while (mayBeMore);
}
use of soot.jimple.IfStmt in project soot by Sable.
the class ConditionalJumpInstruction method jimplify.
public void jimplify(DexBody body) {
// check if target instruction has been jimplified
if (getTargetInstruction(body).getUnit() != null) {
IfStmt s = ifStatement(body);
body.add(s);
setUnit(s);
} else {
// set marker unit to swap real gotostmt with otherwise
body.addDeferredJimplification(this);
markerUnit = Jimple.v().newNopStmt();
unit = markerUnit;
// beginUnit = markerUnit;
// endUnit = markerUnit;
// beginUnit = markerUnit;
body.add(markerUnit);
// Unit end = Jimple.v().newNopStmt();
// body.add(end);
// endUnit = end;
}
}
use of soot.jimple.IfStmt in project soot by Sable.
the class StmtVisitor method caseIfStmt.
@Override
public void caseIfStmt(IfStmt stmt) {
Stmt target = stmt.getTarget();
exprV.setOrigStmt(stmt);
exprV.setTargetForOffset(target);
stmt.getCondition().apply(exprV);
}
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