com.googlecode.dex2jar.ir.ts.array.ArrayNullPointerTransformer Maven / Gradle / Ivy
/*
* dex2jar - Tools to work with android .dex and java .class files
* Copyright (c) 2009-2012 Panxiaobo
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.googlecode.dex2jar.ir.ts.array;
import java.util.ArrayList;
import java.util.List;
import com.googlecode.dex2jar.ir.IrMethod;
import com.googlecode.dex2jar.ir.expr.ArrayExpr;
import com.googlecode.dex2jar.ir.expr.Constant;
import com.googlecode.dex2jar.ir.expr.Exprs;
import com.googlecode.dex2jar.ir.expr.FieldExpr;
import com.googlecode.dex2jar.ir.expr.Local;
import com.googlecode.dex2jar.ir.expr.Value;
import com.googlecode.dex2jar.ir.expr.Value.E1Expr;
import com.googlecode.dex2jar.ir.expr.Value.E2Expr;
import com.googlecode.dex2jar.ir.expr.Value.EnExpr;
import com.googlecode.dex2jar.ir.expr.Value.VT;
import com.googlecode.dex2jar.ir.stmt.Stmt;
import com.googlecode.dex2jar.ir.stmt.Stmt.E1Stmt;
import com.googlecode.dex2jar.ir.stmt.Stmt.E2Stmt;
import com.googlecode.dex2jar.ir.stmt.Stmt.ST;
import com.googlecode.dex2jar.ir.stmt.StmtList;
import com.googlecode.dex2jar.ir.stmt.Stmts;
import com.googlecode.dex2jar.ir.ts.Transformer;
/**
* run after {@link com.googlecode.dex2jar.ir.ts.ConstTransformer}, to deal with following code
*
*
* int[] a = null;
* int b = a[1];
*
*
* replace {@code int b = a[1];} to {@code throw new NullPointException()}, and we get
*
*
* int[] a = null;
* throw new NullPointException();
*
*
* @author Panxiaobo
*
*/
public class ArrayNullPointerTransformer implements Transformer {
@Override
public void transform(IrMethod irMethod) {
for (Stmt p = irMethod.stmts.getFirst(); p != null;) {
if (arrayNPE(p)) {
Stmt q = p.getNext();
replaceNPE(irMethod.stmts, irMethod.locals, p);
p = q;
continue;
}
p = p.getNext();
}
}
private void replaceNPE(StmtList stmts, List locals, Stmt p) {
List values = new ArrayList();
switch (p.et) {
case E1:
tryAdd(((E1Stmt) p).op.trim(), values);
break;
case E2:
E2Stmt e2 = (E2Stmt) p;
switch (e2.op1.trim().vt) {
case LOCAL:
tryAdd(e2.op2.trim(), values);
break;
case ARRAY:
ArrayExpr ae = (ArrayExpr) e2.op1.trim();
if (tryAdd(ae.op1.trim(), values)) {
if (tryAdd(ae.op2.trim(), values)) {
tryAdd(e2.op2.trim(), values);
}
}
break;
case FIELD:// putfield
FieldExpr fe = (FieldExpr) e2.op1.trim();
if (fe.op == null || fe.op.trim() == null || tryAdd(fe.op.trim(), values)) {
tryAdd(e2.op2.trim(), values);
}
break;
default:
if (tryAdd(e2.op2.trim(), values)) {
tryAdd(e2.op1.trim(), values);
}
}
default:
}
for (Value value : values) {
switch (value.vt) {
case CONSTANT:
case LOCAL:
break;
default:
Local n = Exprs.nLocal("xxx");
locals.add(n);
stmts.insertBefore(p, Stmts.nAssign(n, value));
}
}
stmts.insertBefore(p,
Stmts.nThrow(Exprs.nInvokeNew(new Value[0], new String[0], "Ljava/lang/NullPointerException;")));
stmts.remove(p);
}
private boolean tryAdd(Value value, List values) {
if (!arrayNPE(value)) {
values.add(value);
return true;
} else {
switch (value.et) {
case E0:
values.add(value);
break;
case E1:
E1Expr e1 = (E1Expr) value;
if (e1.op == null || e1.op.trim() == null) {
return false;
}
tryAdd(e1.op.trim(), values);
break;
case E2:
E2Expr e2 = (E2Expr) value;
if (e2.vt == VT.ARRAY && e2.op1.trim().vt == VT.CONSTANT) {
Constant cst = (Constant) e2.op1.trim();
if (cst.value.equals(Integer.valueOf(0))) {
tryAdd(e2.op2.trim(), values);
return false;
}
}
if (tryAdd(e2.op1.trim(), values)) {
tryAdd(e2.op2.trim(), values);
}
case En:
for (Value vb : ((EnExpr) value).ops) {
if (!tryAdd(vb.trim(), values)) {
break;
}
}
}
}
return false;
}
private boolean arrayNPE(Stmt p) {
switch (p.et) {
case E0:
return false;
case E1:
if (p.st == ST.GOTO) {
return false;
}
return arrayNPE(((E1Stmt) p).op.trim());
case E2:
E2Stmt e2 = (E2Stmt) p;
switch (e2.op1.trim().vt) {
case ARRAY:
case FIELD:
return arrayNPE(e2.op1.trim()) || arrayNPE(e2.op2.trim());
default:
return arrayNPE(e2.op2.trim()) || arrayNPE(e2.op1.trim());
}
case En:
return false;
}
return false;
}
private boolean arrayNPE(Value value) {
switch (value.et) {
case E0:
return false;
case E1:
E1Expr e1 = (E1Expr) value;
if (e1.op == null || e1.op.trim() == null) {
return false;
}
return arrayNPE(e1.op.trim());
case E2:
E2Expr e2 = (E2Expr) value;
if (e2.vt == VT.ARRAY && e2.op1.trim().vt == VT.CONSTANT) {
Constant cst = (Constant) e2.op1.trim();
if (cst.value.equals(Integer.valueOf(0))) {
return true;
}
}
return arrayNPE(e2.op1.trim()) || arrayNPE(e2.op2.trim());
case En:
for (Value vb : ((EnExpr) value).ops) {
if (arrayNPE(vb.trim())) {
return true;
}
}
}
return false;
}
}