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jode/jode/jode/obfuscator/ConstantAnalyzer.java

1344 lines
42 KiB

/* ConstantAnalyzer Copyright (C) 1999 Jochen Hoenicke.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
*/
package jode.obfuscator;
import jode.type.MethodType;
import jode.GlobalOptions;
import jode.Obfuscator;
import jode.type.Type;
import jode.bytecode.*;
import jode.jvm.InterpreterException;
import java.util.*;
import java.lang.reflect.Array;
import java.lang.reflect.Modifier;
import java.lang.reflect.InvocationTargetException;
interface ConstantListener {
public void constantChanged();
}
class ConstantAnalyzerValue implements ConstantListener {
public final static Object VOLATILE = new Object();
/**
* The constant value, VOLATILE if value is not constant.
*/
Object value;
/**
* The number of slots this value takes on the stack.
*/
int stackSize;
/**
* The constant listeners, that want to be informed if this is
* no longer constant.
*/
Vector listeners;
public ConstantAnalyzerValue(Object constant) {
value = constant;
stackSize = (constant instanceof Double
|| constant instanceof Long) ? 2 : 1;
listeners = new Vector();
}
public ConstantAnalyzerValue(ConstantAnalyzerValue constant) {
value = constant.value;
stackSize = constant.stackSize;
listeners = new Vector();
constant.addConstantListener(this);
}
public ConstantAnalyzerValue(int stackSize) {
this.value = VOLATILE;
this.stackSize = stackSize;
}
public ConstantAnalyzerValue copy() {
return (value == VOLATILE) ? this : new ConstantAnalyzerValue(this);
}
public void addConstantListener(ConstantListener l) {
if (!listeners.contains(l))
listeners.addElement(l);
}
public void removeConstantListener(ConstantListener l) {
listeners.removeElement(l);
}
public void fireChanged() {
value = VOLATILE;
Enumeration enum = listeners.elements();
while (enum.hasMoreElements())
((ConstantListener) enum.nextElement()).constantChanged();
listeners = null;
}
public void constantChanged() {
if (value != VOLATILE)
fireChanged();
}
/**
* Merge this value with other.
* @return true, if the value changed.
*/
public void merge(ConstantAnalyzerValue other) {
if (this == other
|| (value == VOLATILE && other.value == VOLATILE))
return;
if (value == other.value
|| (value != null && value.equals(other.value))) {
other.addConstantListener(this);
return;
}
if (value != VOLATILE)
fireChanged();
if (other.value != VOLATILE)
other.fireChanged();
}
}
/**
* Analyze the code, assuming every field that is not yet written to
* is constant. This may imply that some code is dead code.
*
* @author Jochen Hoenicke
*/
public class ConstantAnalyzer implements Opcodes, CodeAnalyzer {
boolean working;
MethodIdentifier m;
BytecodeInfo bytecode;
Hashtable constInfos = null;
Stack instrStack;
ConstantRuntimeEnvironment runtime;
final static int REACHABLE = 0x1;
final static int CONSTANT = 0x2;
final static int CONSTANTFLOW = 0x4;
class ConstantAnalyzerInfo implements ConstantListener {
ConstantAnalyzerValue[] stack;
ConstantAnalyzerValue[] locals;
Instruction instr;
public ConstantAnalyzerValue copy(ConstantAnalyzerValue value) {
return (value == null) ? null : value.copy();
}
private ConstantAnalyzerInfo(ConstantAnalyzerValue[] stack,
ConstantAnalyzerValue[] locals) {
this.stack = stack;
this.locals = locals;
}
public ConstantAnalyzerInfo(int numLocals,
boolean isStatic, String methodTypeSig) {
MethodType mt = Type.tMethod(methodTypeSig);
locals = new ConstantAnalyzerValue[numLocals];
stack = new ConstantAnalyzerValue[0];
int slot = 0;
if (!isStatic)
locals[slot++] = new ConstantAnalyzerValue(1);
for (int i=0; i< mt.getParameterTypes().length; i++) {
locals[slot] = new ConstantAnalyzerValue
(mt.getParameterTypes()[i].stackSize());
slot += locals[slot].stackSize;
}
}
public void constantChanged() {
if (!instrStack.contains(instr))
instrStack.push(instr);
}
public ConstantAnalyzerInfo poppush(int pops, ConstantAnalyzerValue push) {
ConstantAnalyzerValue[] newStack
= new ConstantAnalyzerValue[stack.length - pops + push.stackSize];
System.arraycopy(stack, 0, newStack, 0, stack.length-pops);
newStack[stack.length-pops] = push.copy();
return new ConstantAnalyzerInfo(newStack, locals);
}
public ConstantAnalyzerInfo pop(int pops) {
ConstantAnalyzerValue[] newStack
= new ConstantAnalyzerValue[stack.length - pops];
System.arraycopy(stack, 0, newStack, 0, stack.length-pops);
return new ConstantAnalyzerInfo(newStack, locals);
}
public ConstantAnalyzerInfo dup(int count, int depth) {
ConstantAnalyzerValue[] newStack
= new ConstantAnalyzerValue[stack.length + count];
if (depth == 0)
System.arraycopy(stack, 0, newStack, 0, stack.length);
else {
int pos = stack.length - count - depth;
System.arraycopy(stack, 0, newStack, 0, pos);
for (int i=0; i < count; i++)
newStack[pos++] = copy(stack[stack.length-count + i]);
for (int i=0; i < depth; i++)
newStack[pos++] = copy(stack[stack.length-count-depth + i]);
}
for (int i=0; i < count; i++)
newStack[stack.length+i] = copy(stack[stack.length-count + i]);
return new ConstantAnalyzerInfo(newStack, locals);
}
public ConstantAnalyzerInfo swap() {
ConstantAnalyzerValue[] newStack
= new ConstantAnalyzerValue[stack.length];
System.arraycopy(stack, 0, newStack, 0, stack.length - 2);
newStack[stack.length-2] = stack[stack.length-1].copy();
newStack[stack.length-1] = stack[stack.length-2].copy();
return new ConstantAnalyzerInfo(newStack, locals);
}
public ConstantAnalyzerValue getLocal(int slot) {
return locals[slot];
}
public ConstantAnalyzerValue getStack(int depth) {
return stack[stack.length - depth];
}
public ConstantAnalyzerInfo setLocal(int slot,
ConstantAnalyzerValue value) {
ConstantAnalyzerValue[] newLocals
= (ConstantAnalyzerValue[]) locals.clone();
newLocals[slot] = value;
if (value.stackSize == 2)
newLocals[slot+1] = null;
return new ConstantAnalyzerInfo(stack, newLocals);
}
public void merge(ConstantAnalyzerInfo other) {
for (int i=0; i < locals.length; i++) {
if (locals[i] != null) {
if (other.locals[i] == null) {
if (!instrStack.contains(instr))
instrStack.push(instr);
locals[i] = null;
} else {
locals[i].merge(other.locals[i]);
}
}
}
if (stack.length != other.stack.length)
throw new jode.AssertError("stack length differs");
for (int i=0; i < stack.length; i++) {
if ((other.stack[i] == null) != (stack[i] == null))
throw new jode.AssertError("stack types differ");
else if (stack[i] != null)
stack[i].merge(other.stack[i]);
}
}
}
class ConstantInfo implements ConstantListener {
int flags;
/**
* The constant, may be an Instruction for CONSTANTFLOW.
*/
Object constant;
public void constantChanged() {
constant = null;
flags &= ~(CONSTANT | CONSTANTFLOW);
}
}
static ConstantAnalyzerValue[] unknownValue = {
new ConstantAnalyzerValue(1), new ConstantAnalyzerValue(2)
};
public ConstantAnalyzer(BytecodeInfo code, MethodIdentifier method) {
this.bytecode = code;
this.m = method;
this.runtime = new ConstantRuntimeEnvironment(m);
}
public void mergeInfo(Instruction instr,
ConstantAnalyzerInfo info) {
if (instr.tmpInfo == null) {
if (!instrStack.contains(instr))
instrStack.push(instr);
instr.tmpInfo = info;
info.instr = instr;
} else
((ConstantAnalyzerInfo)instr.tmpInfo).merge(info);
}
public void handleReference(Reference ref, boolean isVirtual) {
String clName = ref.getClazz();
/* Don't have to reach array methods */
if (clName.charAt(0) != '[') {
clName = clName.substring(1, clName.length()-1).replace('/', '.');
m.clazz.bundle.reachableIdentifier
(clName+"."+ref.getName()+"."+ref.getType(), isVirtual);
}
}
public void handleClass(String clName) {
int i = 0;
while (i < clName.length() && clName.charAt(i) == '[')
i++;
if (i < clName.length() && clName.charAt(i) == 'L') {
clName = clName.substring(i+1, clName.length()-1);
m.clazz.bundle.reachableIdentifier(clName, false);
}
}
public void handleOpcode(Instruction instr) {
ConstantAnalyzerInfo info = (ConstantAnalyzerInfo) instr.tmpInfo;
ConstantInfo shortInfo = (ConstantInfo) constInfos.get(instr);
if (shortInfo == null)
constInfos.put(instr, shortInfo = new ConstantInfo());
shortInfo.flags = REACHABLE;
int opcode = instr.opcode;
Handler[] handlers = bytecode.getExceptionHandlers();
for (int i=0; i< handlers.length; i++) {
if (handlers[i].start.addr <= instr.addr
&& handlers[i].end.addr >= instr.addr)
mergeInfo(handlers[i].catcher,
info.poppush(info.stack.length, unknownValue[0]));
}
ConstantAnalyzerValue result;
switch (opcode) {
case opc_nop:
mergeInfo(instr.nextByAddr, info.pop(0));
break;
case opc_ldc:
case opc_ldc2_w:
result = new ConstantAnalyzerValue(instr.objData);
mergeInfo(instr.nextByAddr, info.poppush(0, result));
break;
case opc_iload: case opc_lload:
case opc_fload: case opc_dload: case opc_aload:
result = info.getLocal(instr.localSlot);
if (result.value != ConstantAnalyzerValue.VOLATILE) {
shortInfo.flags |= CONSTANT;
shortInfo.constant = result.value;
result.addConstantListener(shortInfo);
}
mergeInfo(instr.nextByAddr,
info.setLocal(instr.localSlot, result.copy())
.poppush(0, result));
break;
case opc_iaload: case opc_laload:
case opc_faload: case opc_daload: case opc_aaload:
case opc_baload: case opc_caload: case opc_saload: {
// ConstantAnalyzerValue array = info.getStack(2);
// ConstantAnalyzerValue index = info.getStack(1);
// ConstantAnalyzerValue newValue = null;
// if (index.value != index.ConstantAnalyzerValue.VOLATILE
// && array.value != array.ConstantAnalyzerValue.VOLATILE
// && array.value != null) {
// int indexVal = ((Integer) index.value).intValue();
// Object content;
// switch(opcode) {
// case opc_baload:
// content = new Integer
// (array.value instanceof byte[]
// ? ((byte[])array.value)[indexVal]
// : ((boolean[])array.value)[indexVal] ? 1 : 0);
// case opc_caload:
// content = new Integer(((char[])array.value)[indexVal]);
// break;
// case opc_saload:
// content = new Integer(((short[])array.value)[indexVal]);
// break;
// case opc_iaload:
// case opc_laload:
// case opc_faload:
// case opc_daload:
// case opc_aaload:
// content = Array.get(array.value, indexVal);
// break;
// default:
// throw new jode.AssertError("Can't happen.");
// }
// result = new ConstantAnalyzerValue(content);
// array.addConstantListener(result);
// index.addConstantListener(result);
// } else {
result = unknownValue[(opcode == opc_laload
|| opcode == opc_daload) ? 1 : 0];
// }
mergeInfo(instr.nextByAddr, info.poppush(2, result));
break;
}
case opc_istore: case opc_fstore: case opc_astore: {
mergeInfo(instr.nextByAddr,
info.pop(1).setLocal(instr.localSlot, info.getStack(1)));
break;
}
case opc_lstore: case opc_dstore: {
mergeInfo(instr.nextByAddr,
info.pop(2).setLocal(instr.localSlot, info.getStack(2)));
break;
}
case opc_iastore: case opc_lastore:
case opc_fastore: case opc_dastore: case opc_aastore:
case opc_bastore: case opc_castore: case opc_sastore: {
int size = (opcode == opc_lastore
|| opcode == opc_dastore) ? 2 : 1;
mergeInfo(instr.nextByAddr, info.pop(2+size));
break;
}
case opc_pop: case opc_pop2:
mergeInfo(instr.nextByAddr, info.pop(opcode - (opc_pop - 1)));
break;
case opc_dup: case opc_dup_x1: case opc_dup_x2:
case opc_dup2: case opc_dup2_x1: case opc_dup2_x2:
mergeInfo(instr.nextByAddr,
info.dup((opcode - (opc_dup - 3)) / 3,
(opcode - (opc_dup - 3)) % 3));
break;
case opc_swap:
mergeInfo(instr.nextByAddr, info.swap());
break;
case opc_iadd: case opc_ladd: case opc_fadd: case opc_dadd:
case opc_isub: case opc_lsub: case opc_fsub: case opc_dsub:
case opc_imul: case opc_lmul: case opc_fmul: case opc_dmul:
case opc_idiv: case opc_ldiv: case opc_fdiv: case opc_ddiv:
case opc_irem: case opc_lrem: case opc_frem: case opc_drem:
case opc_iand: case opc_land:
case opc_ior : case opc_lor :
case opc_ixor: case opc_lxor: {
int size = 1 + (opcode - opc_iadd & 1);
ConstantAnalyzerValue value1 = info.getStack(2*size);
ConstantAnalyzerValue value2 = info.getStack(1*size);
if (value1.value != ConstantAnalyzerValue.VOLATILE
&& value2.value != ConstantAnalyzerValue.VOLATILE) {
Object newValue;
switch (opcode) {
case opc_iadd:
newValue = new Integer
(((Integer)value1.value).intValue()
+ ((Integer)value2.value).intValue());
break;
case opc_isub:
newValue = new Integer
(((Integer)value1.value).intValue()
- ((Integer)value2.value).intValue());
break;
case opc_imul:
newValue = new Integer
(((Integer)value1.value).intValue()
* ((Integer)value2.value).intValue());
break;
case opc_idiv:
newValue = new Integer
(((Integer)value1.value).intValue()
/ ((Integer)value2.value).intValue());
break;
case opc_irem:
newValue = new Integer
(((Integer)value1.value).intValue()
% ((Integer)value2.value).intValue());
break;
case opc_iand:
newValue = new Integer
(((Integer)value1.value).intValue()
& ((Integer)value2.value).intValue());
break;
case opc_ior:
newValue = new Integer
(((Integer)value1.value).intValue()
| ((Integer)value2.value).intValue());
break;
case opc_ixor:
newValue = new Integer
(((Integer)value1.value).intValue()
^ ((Integer)value2.value).intValue());
break;
case opc_ladd:
newValue = new Long
(((Long)value1.value).longValue()
+ ((Long)value2.value).longValue());
break;
case opc_lsub:
newValue = new Long
(((Long)value1.value).longValue()
- ((Long)value2.value).longValue());
break;
case opc_lmul:
newValue = new Long
(((Long)value1.value).longValue()
* ((Long)value2.value).longValue());
break;
case opc_ldiv:
newValue = new Long
(((Long)value1.value).longValue()
/ ((Long)value2.value).longValue());
break;
case opc_lrem:
newValue = new Long
(((Long)value1.value).longValue()
% ((Long)value2.value).longValue());
break;
case opc_land:
newValue = new Long
(((Long)value1.value).longValue()
& ((Long)value2.value).longValue());
break;
case opc_lor:
newValue = new Long
(((Long)value1.value).longValue()
| ((Long)value2.value).longValue());
break;
case opc_lxor:
newValue = new Long
(((Long)value1.value).longValue()
^ ((Long)value2.value).longValue());
break;
case opc_fadd:
newValue = new Float
(((Float)value1.value).floatValue()
+ ((Float)value2.value).floatValue());
break;
case opc_fsub:
newValue = new Float
(((Float)value1.value).floatValue()
- ((Float)value2.value).floatValue());
break;
case opc_fmul:
newValue = new Float
(((Float)value1.value).floatValue()
* ((Float)value2.value).floatValue());
break;
case opc_fdiv:
newValue = new Float
(((Float)value1.value).floatValue()
/ ((Float)value2.value).floatValue());
break;
case opc_frem:
newValue = new Float
(((Float)value1.value).floatValue()
% ((Float)value2.value).floatValue());
break;
case opc_dadd:
newValue = new Double
(((Double)value1.value).doubleValue()
+ ((Double)value2.value).doubleValue());
break;
case opc_dsub:
newValue = new Double
(((Double)value1.value).doubleValue()
- ((Double)value2.value).doubleValue());
break;
case opc_dmul:
newValue = new Double
(((Double)value1.value).doubleValue()
* ((Double)value2.value).doubleValue());
break;
case opc_ddiv:
newValue = new Double
(((Double)value1.value).doubleValue()
/ ((Double)value2.value).doubleValue());
break;
case opc_drem:
newValue = new Double
(((Double)value1.value).doubleValue()
% ((Double)value2.value).doubleValue());
break;
default:
throw new jode.AssertError("Can't happen.");
}
shortInfo.flags |= CONSTANT;
shortInfo.constant = newValue;
result = new ConstantAnalyzerValue(newValue);
result.addConstantListener(shortInfo);
value1.addConstantListener(result);
value2.addConstantListener(result);
} else
result = unknownValue[size-1];
mergeInfo(instr.nextByAddr, info.poppush(2*size, result));
break;
}
case opc_ineg: case opc_lneg: case opc_fneg: case opc_dneg: {
int size = 1 + (opcode - opc_ineg & 1);
ConstantAnalyzerValue value = info.getStack(size);
if (value.value != ConstantAnalyzerValue.VOLATILE) {
Object newValue;
switch (opcode) {
case opc_ineg:
newValue = new Integer
(-((Integer)value.value).intValue());
break;
case opc_lneg:
newValue = new Long
(- ((Long)value.value).longValue());
break;
case opc_fneg:
newValue = new Float
(- ((Float)value.value).floatValue());
break;
case opc_dneg:
newValue = new Double
(- ((Double)value.value).doubleValue());
break;
default:
throw new jode.AssertError("Can't happen.");
}
shortInfo.flags |= CONSTANT;
shortInfo.constant = newValue;
result = new ConstantAnalyzerValue(newValue);
result.addConstantListener(shortInfo);
value.addConstantListener(result);
} else
result = unknownValue[size-1];
mergeInfo(instr.nextByAddr, info.poppush(size, result));
break;
}
case opc_ishl: case opc_lshl:
case opc_ishr: case opc_lshr:
case opc_iushr: case opc_lushr: {
int size = 1 + (opcode - opc_iadd & 1);
ConstantAnalyzerValue value1 = info.getStack(size+1);
ConstantAnalyzerValue value2 = info.getStack(1);
if (value1.value != ConstantAnalyzerValue.VOLATILE
&& value2.value != ConstantAnalyzerValue.VOLATILE) {
Object newValue;
switch (opcode) {
case opc_ishl:
newValue = new Integer
(((Integer)value1.value).intValue()
<< ((Integer)value2.value).intValue());
break;
case opc_ishr:
newValue = new Integer
(((Integer)value1.value).intValue()
>> ((Integer)value2.value).intValue());
break;
case opc_iushr:
newValue = new Integer
(((Integer)value1.value).intValue()
>>> ((Integer)value2.value).intValue());
break;
case opc_lshl:
newValue = new Long
(((Long)value1.value).longValue()
<< ((Integer)value2.value).intValue());
break;
case opc_lshr:
newValue = new Long
(((Long)value1.value).longValue()
>> ((Integer)value2.value).intValue());
break;
case opc_lushr:
newValue = new Long
(((Long)value1.value).longValue()
>>> ((Integer)value2.value).intValue());
break;
default:
throw new jode.AssertError("Can't happen.");
}
shortInfo.flags |= CONSTANT;
shortInfo.constant = newValue;
result = new ConstantAnalyzerValue(newValue);
result.addConstantListener(shortInfo);
value1.addConstantListener(result);
value2.addConstantListener(result);
} else
result = unknownValue[size-1];
mergeInfo(instr.nextByAddr, info.poppush(size+1, result));
break;
}
case opc_iinc: {
ConstantAnalyzerValue local = info.getLocal(instr.localSlot);
if (local.value != ConstantAnalyzerValue.VOLATILE) {
result = new ConstantAnalyzerValue
(new Integer(((Integer)local.value).intValue()
+ instr.intData));
local.addConstantListener(result);
} else
result = unknownValue[0];
mergeInfo(instr.nextByAddr,
info.setLocal(instr.localSlot, result));
break;
}
case opc_i2l: case opc_i2f: case opc_i2d:
case opc_l2i: case opc_l2f: case opc_l2d:
case opc_f2i: case opc_f2l: case opc_f2d:
case opc_d2i: case opc_d2l: case opc_d2f: {
int insize = 1 + ((opcode - opc_i2l) / 3 & 1);
ConstantAnalyzerValue stack = info.getStack(insize);
if (stack.value != ConstantAnalyzerValue.VOLATILE) {
Object newVal;
switch(opcode) {
case opc_l2i: case opc_f2i: case opc_d2i:
newVal = new Integer(((Number)stack.value).intValue());
break;
case opc_i2l: case opc_f2l: case opc_d2l:
newVal = new Long(((Number)stack.value).longValue());
break;
case opc_i2f: case opc_l2f: case opc_d2f:
newVal = new Float(((Number)stack.value).floatValue());
break;
case opc_i2d: case opc_l2d: case opc_f2d:
newVal = new Double(((Number)stack.value).doubleValue());
break;
default:
throw new jode.AssertError("Can't happen.");
}
shortInfo.flags |= CONSTANT;
shortInfo.constant = newVal;
result = new ConstantAnalyzerValue(newVal);
result.addConstantListener(shortInfo);
stack.addConstantListener(result);
} else {
switch (opcode) {
case opc_i2l: case opc_f2l: case opc_d2l:
case opc_i2d: case opc_l2d: case opc_f2d:
result = unknownValue[1];
break;
default:
result = unknownValue[0];
}
}
mergeInfo(instr.nextByAddr, info.poppush(insize, result));
break;
}
case opc_i2b: case opc_i2c: case opc_i2s: {
ConstantAnalyzerValue stack = info.getStack(1);
if (stack.value != ConstantAnalyzerValue.VOLATILE) {
int val = ((Integer)stack.value).intValue();
switch(opcode) {
case opc_i2b:
val = (byte) val;
break;
case opc_i2c:
val = (char) val;
break;
case opc_i2s:
val = (short) val;
break;
}
shortInfo.flags |= CONSTANT;
shortInfo.constant = new Integer(val);
result = new ConstantAnalyzerValue(shortInfo.constant);
stack.addConstantListener(shortInfo);
stack.addConstantListener(result);
} else
result = unknownValue[0];
mergeInfo(instr.nextByAddr,
info.poppush(1, result));
break;
}
case opc_lcmp: {
ConstantAnalyzerValue val1 = info.getStack(4);
ConstantAnalyzerValue val2 = info.getStack(2);
if (val1.value != ConstantAnalyzerValue.VOLATILE
&& val2.value != ConstantAnalyzerValue.VOLATILE) {
long value1 = ((Long) val1.value).longValue();
long value2 = ((Long) val1.value).longValue();
shortInfo.flags |= CONSTANT;
shortInfo.constant = new Integer(value1 == value2 ? 0
: value1 < value2 ? -1 : 1);
result = new ConstantAnalyzerValue(shortInfo.constant);
result.addConstantListener(shortInfo);
val1.addConstantListener(result);
val2.addConstantListener(result);
} else
result = unknownValue[0];
mergeInfo(instr.nextByAddr, info.poppush(4, result));
break;
}
case opc_fcmpl: case opc_fcmpg: {
ConstantAnalyzerValue val1 = info.getStack(2);
ConstantAnalyzerValue val2 = info.getStack(1);
if (val1.value != ConstantAnalyzerValue.VOLATILE
&& val2.value != ConstantAnalyzerValue.VOLATILE) {
float value1 = ((Float) val1.value).floatValue();
float value2 = ((Float) val1.value).floatValue();
shortInfo.flags |= CONSTANT;
shortInfo.constant = new Integer
(value1 == value2 ? 0
: ( opcode == opc_fcmpg
? (value1 < value2 ? -1 : 1)
: (value1 > value2 ? 1 : -1)));
result = new ConstantAnalyzerValue(shortInfo.constant);
result.addConstantListener(shortInfo);
val1.addConstantListener(result);
val2.addConstantListener(result);
} else
result = unknownValue[0];
mergeInfo(instr.nextByAddr, info.poppush(2, result));
break;
}
case opc_dcmpl: case opc_dcmpg: {
ConstantAnalyzerValue val1 = info.getStack(4);
ConstantAnalyzerValue val2 = info.getStack(2);
if (val1.value != ConstantAnalyzerValue.VOLATILE
&& val2.value != ConstantAnalyzerValue.VOLATILE) {
double value1 = ((Double) val1.value).doubleValue();
double value2 = ((Double) val1.value).doubleValue();
shortInfo.flags |= CONSTANT;
shortInfo.constant = new Integer
(value1 == value2 ? 0
: ( opcode == opc_dcmpg
? (value1 < value2 ? -1 : 1)
: (value1 > value2 ? 1 : -1)));
result = new ConstantAnalyzerValue(shortInfo.constant);
result.addConstantListener(shortInfo);
val1.addConstantListener(result);
val2.addConstantListener(result);
} else
result = unknownValue[0];
mergeInfo(instr.nextByAddr, info.poppush(4, result));
break;
}
case opc_ifeq: case opc_ifne:
case opc_iflt: case opc_ifge:
case opc_ifgt: case opc_ifle:
case opc_if_icmpeq: case opc_if_icmpne:
case opc_if_icmplt: case opc_if_icmpge:
case opc_if_icmpgt: case opc_if_icmple:
case opc_if_acmpeq: case opc_if_acmpne:
case opc_ifnull: case opc_ifnonnull: {
int size = 1;
ConstantAnalyzerValue stacktop = info.getStack(1);
ConstantAnalyzerValue other = null;
boolean known = stacktop.value != ConstantAnalyzerValue.VOLATILE;
if (opcode >= opc_if_icmpeq && opcode <= opc_if_acmpne) {
other = info.getStack(2);
size = 2;
known &= other.value != ConstantAnalyzerValue.VOLATILE;
}
if (known) {
stacktop.addConstantListener(info);
if (other != null)
other.addConstantListener(info);
Instruction pc = instr.nextByAddr;
int value = -1;
if (opcode >= opc_if_acmpeq) {
if (opcode >= opc_ifnull) {
value = stacktop.value == null ? 0 : 1;
opcode += opc_ifeq - opc_ifnull;
} else {
value = stacktop.value == other.value ? 0 : 1;
}
} else {
value = ((Integer) stacktop.value).intValue();
if (opcode >= opc_if_icmpeq) {
int val1 = ((Integer) other.value).intValue();
value = (val1 == value ? 0
: val1 < value ? -1 : 1);
opcode += opc_ifeq - opc_if_icmpeq;
}
}
if (value > 0 && (opcode == opc_ifgt || opcode == opc_ifge)
|| value < 0 && (opcode == opc_iflt || opcode == opc_ifle)
|| value == 0 && (opcode == opc_ifge || opcode == opc_ifle
|| opcode == opc_ifeq))
pc = instr.succs[0];
shortInfo.flags |= CONSTANTFLOW;
shortInfo.constant = pc;
mergeInfo(pc, info.pop(size));
} else {
mergeInfo(instr.nextByAddr, info.pop(size));
mergeInfo(instr.succs[0], info.pop(size));
}
break;
}
case opc_goto:
mergeInfo(instr.succs[0], info.pop(0));
break;
case opc_jsr:
mergeInfo(instr.nextByAddr, info.pop(0));
mergeInfo(instr.succs[0], info.poppush(0, unknownValue[0]));
break;
case opc_tableswitch: {
ConstantAnalyzerValue stacktop = info.getStack(1);
if (stacktop.value != ConstantAnalyzerValue.VOLATILE) {
stacktop.addConstantListener(info);
Instruction pc;
int value = ((Integer) stacktop.value).intValue();
int low = instr.intData;
if (value >= low && value <= low + instr.succs.length - 2)
pc = instr.succs[value - low];
else
pc = instr.succs[instr.succs.length-1];
shortInfo.flags |= CONSTANTFLOW;
shortInfo.constant = pc;
mergeInfo(pc, info.pop(1));
} else {
for (int i=0; i < instr.succs.length; i++)
mergeInfo(instr.succs[i], info.pop(1));
}
break;
}
case opc_lookupswitch: {
ConstantAnalyzerValue stacktop = info.getStack(1);
if (stacktop.value != ConstantAnalyzerValue.VOLATILE) {
stacktop.addConstantListener(info);
Instruction pc;
int value = ((Integer) stacktop.value).intValue();
int[] values = (int[]) instr.objData;
pc = instr.succs[values.length];
for (int i=0; i< values.length; i++) {
if (values[i] == value) {
pc = instr.succs[i];
break;
}
}
shortInfo.flags |= CONSTANTFLOW;
shortInfo.constant = pc;
mergeInfo(pc, info.pop(1));
} else {
for (int i=0; i < instr.succs.length; i++)
mergeInfo(instr.succs[i], info.pop(1));
}
break;
}
case opc_ret:
case opc_ireturn: case opc_lreturn:
case opc_freturn: case opc_dreturn: case opc_areturn:
case opc_return:
case opc_athrow:
break;
case opc_putstatic:
case opc_putfield: {
int size = (opcode == opc_putstatic) ? 0 : 1;
Reference ref = (Reference) instr.objData;
FieldIdentifier fi = (FieldIdentifier)
m.clazz.bundle.getIdentifier(ref);
if (fi != null && !fi.isNotConstant()) {
fi.setNotConstant();
fieldNotConstant(fi);
}
Type type = Type.tType(ref.getType());
mergeInfo(instr.nextByAddr, info.pop(size + type.stackSize()));
break;
}
case opc_getstatic:
case opc_getfield: {
int size = (opcode == opc_getstatic) ? 0 : 1;
Reference ref = (Reference) instr.objData;
Type type = Type.tType(ref.getType());
FieldIdentifier fi = (FieldIdentifier)
m.clazz.bundle.getIdentifier(ref);
if (fi != null) {
if (fi.isNotConstant()) {
fi.setReachable();
result = unknownValue[type.stackSize()-1];
} else {
Object obj = fi.getConstant();
if (obj == null)
obj = type.getDefaultValue();
shortInfo.flags |= CONSTANT;
shortInfo.constant = obj;
result = new ConstantAnalyzerValue(obj);
result.addConstantListener(shortInfo);
fi.addFieldListener(m);
}
} else
result = unknownValue[type.stackSize()-1];
mergeInfo(instr.nextByAddr, info.poppush(size, result));
break;
}
case opc_invokespecial:
case opc_invokestatic:
case opc_invokeinterface:
case opc_invokevirtual: {
Reference ref = (Reference) instr.objData;
MethodType mt = (MethodType) Type.tType(ref.getType());
boolean constant = true;
int size = 0;
Object cls = null;
Object[] args = new Object[mt.getParameterTypes().length];
ConstantAnalyzerValue clsValue = null;
ConstantAnalyzerValue[] argValues =
new ConstantAnalyzerValue[mt.getParameterTypes().length];
for (int i=mt.getParameterTypes().length-1; i >=0; i--) {
size += mt.getParameterTypes()[i].stackSize();
argValues[i] = info.getStack(size);
if (argValues[i].value != ConstantAnalyzerValue.VOLATILE)
args[i] = argValues[i].value;
else
constant = false;
}
if (opcode != opc_invokestatic) {
size++;
clsValue = info.getStack(size);
cls = clsValue.value;
if (cls == ConstantAnalyzerValue.VOLATILE
|| cls == null
|| !cls.getClass().getName().equals(ref.getClazz()))
constant = false;
}
Type retType = mt.getReturnType();
if (retType == Type.tVoid) {
handleReference(ref, opcode == opc_invokevirtual
|| opcode == opc_invokeinterface);
mergeInfo(instr.nextByAddr, info.pop(size));
break;
}
if (constant
&& retType != Type.tString
&& retType.getTypeSignature().length() != 1) {
/* This is not a valid constant type */
constant = false;
}
Object methodResult = null;
if (constant) {
try {
methodResult = runtime.invokeMethod
(ref, opcode != opc_invokespecial, cls, args);
} catch (InterpreterException ex) {
constant = false;
if (jode.GlobalOptions.verboseLevel > 3)
GlobalOptions.err.println("Can't interpret "+ref+": "
+ ex.getMessage());
/* result is not constant */
} catch (InvocationTargetException ex) {
constant = false;
if (jode.GlobalOptions.verboseLevel > 3)
GlobalOptions.err.println("Method "+ref
+" throwed exception: "
+ ex.getTargetException()
.getMessage());
/* method always throws exception ? */
}
}
ConstantAnalyzerValue returnVal;
if (!constant) {
handleReference(ref, opcode == opc_invokevirtual
|| opcode == opc_invokeinterface);
returnVal =
unknownValue[mt.getReturnType().stackSize()-1];
} else {
shortInfo.flags |= CONSTANT;
shortInfo.constant = methodResult;
returnVal = new ConstantAnalyzerValue(methodResult);
returnVal.addConstantListener(shortInfo);
if (clsValue != null)
clsValue.addConstantListener(returnVal);
for (int i=0; i< argValues.length; i++)
argValues[i].addConstantListener(returnVal);
}
mergeInfo(instr.nextByAddr, info.poppush(size, returnVal));
break;
}
case opc_new: {
handleClass((String) instr.objData);
mergeInfo(instr.nextByAddr, info.poppush(0, unknownValue[0]));
break;
}
case opc_arraylength: {
// ConstantAnalyzerValue array = info.getStack(1);
// if (array.value != ConstantAnalyzerValue.VOLATILE
// && array.value != null) {
// shortInfo.flags |= CONSTANT;
// shortInfo.constant = new Integer(Array.getLength(array.value));
// result = new ConstantAnalyzerValue(shortInfo.constant);
// result.addConstantListener(shortInfo);
// array.addConstantListener(result);
// } else
result = unknownValue[0];
mergeInfo(instr.nextByAddr, info.poppush(1, result));
break;
}
case opc_checkcast: {
handleClass((String) instr.objData);
mergeInfo(instr.nextByAddr, info.pop(0));
break;
}
case opc_instanceof: {
handleClass((String) instr.objData);
mergeInfo(instr.nextByAddr, info.poppush(1, unknownValue[0]));
break;
}
case opc_monitorenter:
case opc_monitorexit:
mergeInfo(instr.nextByAddr, info.pop(1));
break;
case opc_multianewarray:
handleClass((String) instr.objData);
mergeInfo(instr.nextByAddr,
info.poppush(instr.intData, unknownValue[0]));
break;
default:
throw new jode.AssertError("Invalid opcode "+opcode);
}
}
public void analyzeCode() {
working = true;
if (constInfos == null)
constInfos = new Hashtable();
instrStack = new Stack();
bytecode.getFirstInstr().tmpInfo = new ConstantAnalyzerInfo
(bytecode.getMaxLocals(), m.info.isStatic(), m.info.getType());
instrStack.push(bytecode.getFirstInstr());
while (!instrStack.isEmpty()) {
Instruction instr = (Instruction) instrStack.pop();
handleOpcode(instr);
}
Handler[] handlers = bytecode.getExceptionHandlers();
for (int i=0; i< handlers.length; i++) {
if (handlers[i].catcher.tmpInfo != null
&& handlers[i].type != null)
m.clazz.bundle.reachableIdentifier(handlers[i].type, false);
}
working = false;
for (Instruction instr = bytecode.getFirstInstr();
instr != null; instr = instr.nextByAddr)
instr.tmpInfo = null;
instrStack = null;
// System.gc();
}
public void fieldNotConstant(FieldIdentifier fi) {
for (Instruction instr = bytecode.getFirstInstr();
instr != null; instr = instr.nextByAddr) {
if (instr.opcode == opc_getfield
|| instr.opcode == opc_getstatic) {
Reference ref = (Reference) instr.objData;
if (ref.getName().equals(fi.getName())
&& ref.getType().equals(fi.getType())
&& instr.tmpInfo != null) {
if (!instrStack.contains(instr))
instrStack.push(instr);
}
}
}
}
public void insertOnePop(Instruction instr, int count) {
/* Add a goto instruction after this opcode. */
Instruction pop = instr.insertInstruction();
pop.length = 1;
pop.opcode = Instruction.opc_pop - 1 + count;
}
public void insertPop(Instruction instr) {
switch(instr.opcode) {
case opc_ldc:
case opc_ldc2_w:
case opc_iload: case opc_lload:
case opc_fload: case opc_dload: case opc_aload:
case opc_getstatic:
break;
case opc_arraylength:
case opc_getfield:
case opc_i2l: case opc_i2f: case opc_i2d:
case opc_f2i: case opc_f2l: case opc_f2d:
case opc_i2b: case opc_i2c: case opc_i2s:
case opc_ineg: case opc_fneg:
insertOnePop(instr, 1);
break;
case opc_lcmp:
case opc_dcmpg: case opc_dcmpl:
case opc_ladd: case opc_dadd:
case opc_lsub: case opc_dsub:
case opc_lmul: case opc_dmul:
case opc_ldiv: case opc_ddiv:
case opc_lrem: case opc_drem:
case opc_land: case opc_lor : case opc_lxor:
insertOnePop(instr, 2);
/* fall through */
case opc_fcmpg: case opc_fcmpl:
case opc_l2i: case opc_l2f: case opc_l2d:
case opc_d2i: case opc_d2l: case opc_d2f:
case opc_lneg: case opc_dneg:
case opc_iadd: case opc_fadd:
case opc_isub: case opc_fsub:
case opc_imul: case opc_fmul:
case opc_idiv: case opc_fdiv:
case opc_irem: case opc_frem:
case opc_iand: case opc_ior : case opc_ixor:
case opc_ishl: case opc_ishr: case opc_iushr:
case opc_iaload: case opc_laload:
case opc_faload: case opc_daload: case opc_aaload:
case opc_baload: case opc_caload: case opc_saload:
insertOnePop(instr, 2);
break;
case opc_lshl: case opc_lshr: case opc_lushr:
insertOnePop(instr, 1);
insertOnePop(instr, 2);
break;
case opc_putstatic:
case opc_putfield:
if (Type.tType(((Reference)instr.objData).getType())
.stackSize() == 2) {
insertOnePop(instr, 2);
if (instr.opcode == opc_putfield)
insertOnePop(instr, 1);
} else
insertOnePop(instr, (instr.opcode == opc_putfield) ? 2 : 1);
break;
case opc_invokespecial:
case opc_invokestatic:
case opc_invokeinterface:
case opc_invokevirtual: {
Reference ref = (Reference) instr.objData;
MethodType mt = (MethodType) Type.tType(ref.getType());
for (int i=mt.getParameterTypes().length-1; i >=0; i--)
insertOnePop(instr, mt.getParameterTypes()[i].stackSize());
if (instr.opcode != opc_invokestatic)
insertOnePop(instr, 1);
}
}
}
public void appendJump(Instruction instr, Instruction dest) {
/* Add a goto instruction after this opcode. */
Instruction second = instr.appendInstruction();
second.alwaysJumps = true;
second.opcode = Instruction.opc_goto;
second.length = 3;
second.succs = new Instruction[] { dest };
dest.addPredecessor(second);
}
public BytecodeInfo stripCode() {
if (constInfos == null)
analyzeCode();
// bytecode.dumpCode(GlobalOptions.err);
for (Instruction instr = bytecode.getFirstInstr();
instr != null; instr = instr.nextByAddr) {
ConstantInfo info = (ConstantInfo) constInfos.get(instr);
if (info == null || (info.flags & REACHABLE) == 0) {
/* This instruction can't be reached logically */
instr.removeInstruction();
} else if ((info.flags & CONSTANT) != 0) {
insertPop(instr);
if (instr.opcode > opc_ldc2_w) {
instr.opcode = (info.constant instanceof Long
|| info.constant instanceof Double
? opc_ldc2_w : opc_ldc);
instr.localSlot = -1;
instr.length = 2;
instr.objData = info.constant;
if (GlobalOptions.verboseLevel > 2)
GlobalOptions.err.println
(m + ": Replacing " + instr
+ " with constant " + info.constant);
}
instr.tmpInfo = null;
} else if ((info.flags & CONSTANTFLOW) != 0) {
Instruction pc = (Instruction) info.constant;
if (instr.opcode >= opc_if_icmpeq
&& instr.opcode <= opc_if_acmpne)
instr.opcode = opc_pop2;
else
instr.opcode = opc_pop;
if (GlobalOptions.verboseLevel > 2)
GlobalOptions.err.println
(m + ": Replacing " + instr + " with goto " + pc.addr);
instr.alwaysJumps = false;
instr.succs[0].removePredecessor(instr);
instr.succs = null;
instr.length = 1;
while (instr.nextByAddr != null) {
ConstantInfo nextinfo
= (ConstantInfo) constInfos.get(instr.nextByAddr);
if (nextinfo != null && (nextinfo.flags & REACHABLE) != 0)
break;
/* Next instruction can't be reached logically */
instr.nextByAddr.removeInstruction();
}
if (pc != instr.nextByAddr) {
appendJump(instr, pc);
instr = instr.nextByAddr;
}
} else {
int opcode = instr.opcode;
switch (opcode) {
case opc_nop:
instr.removeInstruction();
break;
case opc_goto:
while (instr.nextByAddr != null) {
ConstantInfo nextinfo
= (ConstantInfo) constInfos.get(instr.nextByAddr);
if (nextinfo != null
&& (nextinfo.flags & REACHABLE) != 0)
break;
/* Next instruction can't be reached logically */
instr.nextByAddr.removeInstruction();
}
if (instr.succs[0] == instr.nextByAddr)
instr.removeInstruction();
break;
case opc_ifeq: case opc_ifne:
case opc_iflt: case opc_ifge:
case opc_ifgt: case opc_ifle:
case opc_ifnull: case opc_ifnonnull:
if (instr.succs[0] == instr.nextByAddr) {
instr.opcode = opc_pop;
instr.succs[0].removePredecessor(instr);
instr.succs = null;
}
break;
case opc_if_icmpeq: case opc_if_icmpne:
case opc_if_icmplt: case opc_if_icmpge:
case opc_if_icmpgt: case opc_if_icmple:
case opc_if_acmpeq: case opc_if_acmpne:
if (instr.succs[0] == instr.nextByAddr) {
instr.opcode = opc_pop2;
instr.succs[0].removePredecessor(instr);
instr.succs = null;
}
break;
case opc_putstatic:
case opc_putfield: {
Reference ref = (Reference) instr.objData;
FieldIdentifier fi = (FieldIdentifier)
m.clazz.bundle.getIdentifier(ref);
if (fi != null
&& Obfuscator.shouldStrip && !fi.isReachable()) {
insertPop(instr);
instr.removeInstruction();
}
break;
}
}
instr.tmpInfo = null;
}
}
return bytecode;
}
}