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Add UnusedArgTransformer

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bzip2
Graham 5 years ago
parent d20e3997b4
commit 28369f1d75
2 changed files with 205 additions and 1 deletions
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  1. 4
      deob/src/main/java/dev/openrs2/deob/Deobfuscator.java
  2. 202
      deob/src/main/java/dev/openrs2/deob/transform/UnusedArgTransformer.java

4
deob/src/main/java/dev/openrs2/deob/Deobfuscator.java
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@ -24,6 +24,7 @@ import dev.openrs2.deob.transform.FieldOrderTransformer;
import dev.openrs2.deob.transform.OpaquePredicateTransformer;
import dev.openrs2.deob.transform.OriginalNameTransformer;
import dev.openrs2.deob.transform.RemapTransformer;
import dev.openrs2.deob.transform.UnusedArgTransformer;
import org.objectweb.asm.tree.analysis.AnalyzerException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@ -45,7 +46,8 @@ public final class Deobfuscator {
new BitwiseOpTransformer(),
new RemapTransformer(),
new DummyArgTransformer(),
new DummyLocalTransformer()
new DummyLocalTransformer(),
new UnusedArgTransformer()
);
public static void main(String[] args) throws IOException, AnalyzerException {

202
deob/src/main/java/dev/openrs2/deob/transform/UnusedArgTransformer.java
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@ -0,0 +1,202 @@
package dev.openrs2.deob.transform;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import com.google.common.collect.ImmutableSet;
import dev.openrs2.asm.MemberRef;
import dev.openrs2.asm.MethodNodeUtils;
import dev.openrs2.asm.classpath.ClassPath;
import dev.openrs2.asm.classpath.Library;
import dev.openrs2.asm.transform.Transformer;
import dev.openrs2.deob.ArgRef;
import dev.openrs2.deob.analysis.ConstSourceInterpreter;
import dev.openrs2.deob.remap.TypedRemapper;
import dev.openrs2.util.collect.DisjointSet;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.MethodInsnNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.VarInsnNode;
import org.objectweb.asm.tree.analysis.Analyzer;
import org.objectweb.asm.tree.analysis.AnalyzerException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public final class UnusedArgTransformer extends Transformer {
private static final Logger logger = LoggerFactory.getLogger(UnusedArgTransformer.class);
private static final ImmutableSet<Integer> INT_SORTS = ImmutableSet.of(Type.BOOLEAN, Type.BYTE, Type.SHORT, Type.INT, Type.CHAR);
private static Map<Integer, Integer> createLocalToArgMap(MethodNode method) {
var type = Type.getType(method.desc);
var argumentTypes = type.getArgumentTypes();
var map = new HashMap<Integer, Integer>();
var argIndex = 0;
var localIndex = 0;
if ((method.access & Opcodes.ACC_STATIC) == 0) {
localIndex++;
}
for (var t : argumentTypes) {
map.put(localIndex, argIndex++);
localIndex += t.getSize();
}
return map;
}
private final Set<ArgRef> retainedArgs = new HashSet<>();
private DisjointSet<MemberRef> inheritedMethodSets;
private int deletedArgs;
@Override
protected void preTransform(ClassPath classPath) throws AnalyzerException {
retainedArgs.clear();
inheritedMethodSets = classPath.createInheritedMethodSets();
deletedArgs = 0;
for (var library : classPath.getLibraries()) {
for (var clazz : library) {
for (var method : clazz.methods) {
if ((method.access & (Opcodes.ACC_NATIVE | Opcodes.ACC_ABSTRACT)) == 0) {
populateRetainedArgs(classPath, clazz, method);
}
}
}
}
}
private void populateRetainedArgs(ClassPath classPath, ClassNode clazz, MethodNode method) throws AnalyzerException {
var partition = inheritedMethodSets.get(new MemberRef(clazz.name, method.name, method.desc));
var localToArgMap = createLocalToArgMap(method);
var analyzer = new Analyzer<>(new ConstSourceInterpreter());
var frames = analyzer.analyze(clazz.name, method);
for (var i = 0; i < frames.length; i++) {
var frame = frames[i];
if (frame == null) {
continue;
}
var stackSize = frame.getStackSize();
var insn = method.instructions.get(i);
switch (insn.getOpcode()) {
case Opcodes.ILOAD:
var iload = (VarInsnNode) insn;
var arg = localToArgMap.get(iload.var);
if (arg != null) {
retainedArgs.add(new ArgRef(partition, arg));
}
break;
case Opcodes.INVOKEVIRTUAL:
case Opcodes.INVOKESPECIAL:
case Opcodes.INVOKESTATIC:
case Opcodes.INVOKEINTERFACE:
var invoke = (MethodInsnNode) insn;
var invokePartition = inheritedMethodSets.get(new MemberRef(invoke.owner, invoke.name, invoke.desc));
if (invokePartition == null || TypedRemapper.isMethodImmutable(classPath, invokePartition)) {
continue;
}
var args = Type.getArgumentTypes(invoke.desc).length;
for (var j = 0; j < args; j++) {
var source = frame.getStack(stackSize - args + j);
if (!source.isSingleSourceConstant()) {
retainedArgs.add(new ArgRef(invokePartition, j));
}
}
break;
}
}
}
@Override
protected boolean preTransformMethod(ClassPath classPath, Library library, ClassNode clazz, MethodNode method) throws AnalyzerException {
/* delete unused int args from call sites */
if ((method.access & (Opcodes.ACC_ABSTRACT | Opcodes.ACC_NATIVE)) == 0) {
var analyzer = new Analyzer<>(new ConstSourceInterpreter());
analyzer.analyze(clazz.name, method);
var frames = analyzer.getFrames();
var deadInsns = new ArrayList<AbstractInsnNode>();
for (var i = 0; i < frames.length; i++) {
var frame = frames[i];
if (frame == null) {
continue;
}
var stackSize = frame.getStackSize();
var insn = method.instructions.get(i);
if (insn.getType() != AbstractInsnNode.METHOD_INSN) {
continue;
}
var methodInsn = (MethodInsnNode) insn;
var partition = inheritedMethodSets.get(new MemberRef(methodInsn.owner, methodInsn.name, methodInsn.desc));
if (partition == null || TypedRemapper.isMethodImmutable(classPath, partition)) {
continue;
}
var type = Type.getType(methodInsn.desc);
var argTypes = type.getArgumentTypes();
var newArgTypes = new ArrayList<Type>();
for (var j = 0; j < argTypes.length; j++) {
var argType = argTypes[j];
if (INT_SORTS.contains(argType.getSort()) && !retainedArgs.contains(new ArgRef(partition, j))) {
var source = frame.getStack(stackSize - argTypes.length + j).getSource();
deadInsns.add(source);
} else {
newArgTypes.add(argType);
}
}
methodInsn.desc = Type.getMethodDescriptor(type.getReturnType(), newArgTypes.toArray(Type[]::new));
}
deadInsns.forEach(method.instructions::remove);
}
return false;
}
@Override
protected boolean postTransformMethod(ClassPath classPath, Library library, ClassNode clazz, MethodNode method) {
/* delete unused int args from the method itself */
var partition = inheritedMethodSets.get(new MemberRef(clazz.name, method.name, method.desc));
if (TypedRemapper.isMethodImmutable(classPath, partition)) {
return false;
}
var type = Type.getType(method.desc);
var argTypes = type.getArgumentTypes();
for (var i = argTypes.length - 1; i >= 0; i--) {
var argType = argTypes[i];
if (INT_SORTS.contains(argType.getSort()) && !retainedArgs.contains(new ArgRef(partition, i))) {
MethodNodeUtils.deleteArgument(method, i);
deletedArgs++;
}
}
return false;
}
@Override
protected void postTransform(ClassPath classPath) {
logger.info("Removed {} dummy arguments", deletedArgs);
}
}
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