Add Fernflower Exception transformer

Fernflower fails to decompile any exception handler with an end_pc
(`to` in Fernflower nomenclature) equal to the length of the code array,
even though this is permitted in the class file spec. This transformer
inserts a NOP at the end of any code array that has such an exception
handler.

Signed-off-by: Major <major@emulate.rs>
bzip2
Major 5 years ago
parent e7c3afab19
commit a869d47d11
  1. 4
      deob/src/main/java/dev/openrs2/deob/Deobfuscator.kt
  2. 36
      deob/src/main/java/dev/openrs2/deob/transform/FernflowerExceptionTransformer.kt

@ -18,6 +18,7 @@ import dev.openrs2.deob.transform.DummyArgTransformer
import dev.openrs2.deob.transform.DummyLocalTransformer import dev.openrs2.deob.transform.DummyLocalTransformer
import dev.openrs2.deob.transform.EmptyClassTransformer import dev.openrs2.deob.transform.EmptyClassTransformer
import dev.openrs2.deob.transform.ExceptionTracingTransformer import dev.openrs2.deob.transform.ExceptionTracingTransformer
import dev.openrs2.deob.transform.FernflowerExceptionTransformer
import dev.openrs2.deob.transform.FieldOrderTransformer import dev.openrs2.deob.transform.FieldOrderTransformer
import dev.openrs2.deob.transform.FinalTransformer import dev.openrs2.deob.transform.FinalTransformer
import dev.openrs2.deob.transform.InvokeSpecialTransformer import dev.openrs2.deob.transform.InvokeSpecialTransformer
@ -177,7 +178,8 @@ class Deobfuscator(private val input: Path, private val output: Path) {
MethodOrderTransformer(), MethodOrderTransformer(),
VisibilityTransformer(), VisibilityTransformer(),
OverrideTransformer(), OverrideTransformer(),
OriginalPcRestoreTransformer() OriginalPcRestoreTransformer(),
FernflowerExceptionTransformer()
) )
} }
} }

@ -0,0 +1,36 @@
package dev.openrs2.deob.transform
import com.github.michaelbull.logging.InlineLogger
import dev.openrs2.asm.classpath.ClassPath
import dev.openrs2.asm.classpath.Library
import dev.openrs2.asm.nextReal
import dev.openrs2.asm.transform.Transformer
import org.objectweb.asm.Opcodes
import org.objectweb.asm.tree.ClassNode
import org.objectweb.asm.tree.InsnNode
import org.objectweb.asm.tree.MethodNode
class FernflowerExceptionTransformer : Transformer() {
private var nopsInserted = 0
override fun preTransform(classPath: ClassPath) {
nopsInserted = 0
}
override fun transformCode(classPath: ClassPath, library: Library, clazz: ClassNode, method: MethodNode): Boolean {
if (method.tryCatchBlocks.any { it.end.nextReal == null }) {
method.instructions.add(InsnNode(Opcodes.NOP))
nopsInserted++
}
return false
}
override fun postTransform(classPath: ClassPath) {
logger.info { "Inserted $nopsInserted NOPs to correct Fernflower's exception generation" }
}
private companion object {
private val logger = InlineLogger()
}
}
Loading…
Cancel
Save