Add method for extracting arguments passed to an invoke instruction

Signed-off-by: Graham <gpe@openrs2.org>

asm/src/main/kotlin/org/openrs2/asm/InsnListUtils.kt

@@ -1,23 +1,26 @@
 package org.openrs2.asm
 
+import org.objectweb.asm.Type
 import org.objectweb.asm.tree.AbstractInsnNode
 import org.objectweb.asm.tree.InsnList
 import org.objectweb.asm.tree.LabelNode
+import org.objectweb.asm.tree.MethodInsnNode
 
 private val ANY_INSN = { _: AbstractInsnNode -> true }
 
 public fun getExpression(
     last: AbstractInsnNode,
-    filter: (AbstractInsnNode) -> Boolean = ANY_INSN
+    filter: (AbstractInsnNode) -> Boolean = ANY_INSN,
+    initialHeight: Int = 0
 ): List<AbstractInsnNode>? {
     val expr = mutableListOf<AbstractInsnNode>()
 
-    var height = 0
+    var height = initialHeight
     var insn: AbstractInsnNode? = last
     do {
         val (pops, pushes) = insn!!.stackMetadata
         expr.add(insn)
-        if (insn !== last) {
+        if (insn !== last || initialHeight != 0) {
             height -= pushes
         }
         height += pops
@@ -32,6 +35,24 @@ public fun getExpression(
     return null
 }
 
+public fun getArgumentExpressions(
+    invoke: MethodInsnNode,
+    filter: (AbstractInsnNode) -> Boolean = ANY_INSN
+): List<List<AbstractInsnNode>>? {
+    val exprs = mutableListOf<List<AbstractInsnNode>>()
+
+    var insn: AbstractInsnNode = invoke.previous ?: return null
+
+    for (type in Type.getArgumentTypes(invoke.desc)) {
+        val expr = getExpression(insn, filter, type.size) ?: return null
+        exprs += expr
+
+        insn = expr.first().previous ?: return null
+    }
+
+    return exprs.asReversed()
+}
+
 public fun InsnList.replaceExpression(
     last: AbstractInsnNode,
     replacement: AbstractInsnNode,