Add support for impure expressions to InsnListUtils

asm/src/main/java/dev/openrs2/asm/InsnListUtils.kt

@@ -3,7 +3,13 @@ package dev.openrs2.asm
 import org.objectweb.asm.tree.AbstractInsnNode
 import org.objectweb.asm.tree.InsnList
 
-fun getSimpleExpression(last: AbstractInsnNode): List<AbstractInsnNode>? {
+private val ANY_INSN = { _: AbstractInsnNode -> true }
+private val JUMP_OR_LABEL = listOf(AbstractInsnNode.LABEL, AbstractInsnNode.JUMP_INSN)
+
+fun getExpression(
+    last: AbstractInsnNode,
+    filter: (AbstractInsnNode) -> Boolean = ANY_INSN
+): List<AbstractInsnNode>? {
     val expr = mutableListOf<AbstractInsnNode>()
 
     var height = 0
@@ -21,20 +27,27 @@ fun getSimpleExpression(last: AbstractInsnNode): List<AbstractInsnNode>? {
         }
 
         insn = insn.previous
-    } while (insn != null && insn.type != AbstractInsnNode.LABEL && insn.pure)
+    } while (insn != null && insn.type !in JUMP_OR_LABEL && filter(insn))
 
     return null
 }
 
-fun InsnList.replaceSimpleExpression(last: AbstractInsnNode, replacement: AbstractInsnNode): Boolean {
-    val expr = getSimpleExpression(last) ?: return false
+fun InsnList.replaceExpression(
+    last: AbstractInsnNode,
+    replacement: AbstractInsnNode,
+    filter: (AbstractInsnNode) -> Boolean = ANY_INSN
+): Boolean {
+    val expr = getExpression(last, filter) ?: return false
     expr.forEach(this::remove)
     this[last] = replacement
     return true
 }
 
-fun InsnList.deleteSimpleExpression(last: AbstractInsnNode): Boolean {
-    val expr = getSimpleExpression(last) ?: return false
+fun InsnList.deleteExpression(
+    last: AbstractInsnNode,
+    filter: (AbstractInsnNode) -> Boolean = ANY_INSN
+): Boolean {
+    val expr = getExpression(last, filter) ?: return false
     expr.forEach(this::remove)
     remove(last)
     return true

deob/src/main/java/dev/openrs2/deob/transform/DummyArgTransformer.kt

@@ -8,11 +8,11 @@ import dev.openrs2.asm.MemberRef
 import dev.openrs2.asm.classpath.ClassPath
 import dev.openrs2.asm.classpath.Library
 import dev.openrs2.asm.createIntConstant
-import dev.openrs2.asm.deleteSimpleExpression
+import dev.openrs2.asm.deleteExpression
 import dev.openrs2.asm.intConstant
 import dev.openrs2.asm.nextReal
 import dev.openrs2.asm.pure
-import dev.openrs2.asm.replaceSimpleExpression
+import dev.openrs2.asm.replaceExpression
 import dev.openrs2.asm.stackMetadata
 import dev.openrs2.asm.transform.Transformer
 import dev.openrs2.common.collect.DisjointSet
@@ -297,14 +297,15 @@ class DummyArgTransformer : Transformer() {
         }
 
         for (insn in alwaysTakenBranches) {
-            if (method.instructions.replaceSimpleExpression(insn, JumpInsnNode(Opcodes.GOTO, insn.label))) {
+            val replacement = JumpInsnNode(Opcodes.GOTO, insn.label)
+            if (method.instructions.replaceExpression(insn, replacement, AbstractInsnNode::pure)) {
                 branchesSimplified++
                 changed = true
             }
         }
 
         for (insn in neverTakenBranches) {
-            if (method.instructions.deleteSimpleExpression(insn)) {
+            if (method.instructions.deleteExpression(insn, AbstractInsnNode::pure)) {
                 branchesSimplified++
                 changed = true
             }
@@ -316,7 +317,7 @@ class DummyArgTransformer : Transformer() {
             }
 
             val replacement = createIntConstant(value)
-            if (method.instructions.replaceSimpleExpression(insn, replacement)) {
+            if (method.instructions.replaceExpression(insn, replacement, AbstractInsnNode::pure)) {
                 constantsInlined++
                 changed = true
             }

deob/src/main/java/dev/openrs2/deob/transform/DummyLocalTransformer.kt

@@ -3,7 +3,8 @@ 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.deleteSimpleExpression
+import dev.openrs2.asm.deleteExpression
+import dev.openrs2.asm.pure
 import dev.openrs2.asm.transform.Transformer
 import dev.openrs2.deob.analysis.LiveVariableAnalyzer
 import org.objectweb.asm.Opcodes
@@ -39,7 +40,7 @@ class DummyLocalTransformer : Transformer() {
         }
 
         for (insn in deadStores) {
-            if (method.instructions.deleteSimpleExpression(insn)) {
+            if (method.instructions.deleteExpression(insn, AbstractInsnNode::pure)) {
                 localsRemoved++
             }
         }