Convert stackMetadata to an extension property

It feels much more like a property than a function.

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

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

@@ -14,7 +14,7 @@ fun getExpression(
     var height = 0
     var insn: AbstractInsnNode? = last
     do {
-        val (pops, pushes) = insn!!.stackMetadata()
+        val (pops, pushes) = insn!!.stackMetadata
         if (insn !== last) {
             expr.add(insn)
             height -= pushes

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

@@ -181,36 +181,37 @@ private val SIMPLE_OPCODES = mapOf(
     Opcodes.IFNONNULL to POP1
 )
 
-fun AbstractInsnNode.stackMetadata(): StackMetadata = when (this) {
-    is LdcInsnNode -> if (cst is Double || cst is Long) {
-        PUSH2
-    } else {
-        PUSH1
-    }
-    is FieldInsnNode -> {
-        val fieldSize = Type.getType(desc).size
-        var pushes = 0
-        var pops = 0
-        if (opcode == Opcodes.GETFIELD || opcode == Opcodes.PUTFIELD) {
-            pops++
-        }
-        if (opcode == Opcodes.PUTFIELD || opcode == Opcodes.PUTSTATIC) {
-            pops += fieldSize
+val AbstractInsnNode.stackMetadata
+    get() = when (this) {
+        is LdcInsnNode -> if (cst is Double || cst is Long) {
+            PUSH2
         } else {
-            pushes += fieldSize
+            PUSH1
         }
-        StackMetadata(pops, pushes)
-    }
-    is MethodInsnNode -> {
-        val argumentsAndReturnSizes = Type.getArgumentsAndReturnSizes(desc)
-        val pushes = argumentsAndReturnSizes and 0x3
-        var pops = argumentsAndReturnSizes shr 2
-        if (opcode == Opcodes.INVOKESTATIC) {
-            pops--
+        is FieldInsnNode -> {
+            val fieldSize = Type.getType(desc).size
+            var pushes = 0
+            var pops = 0
+            if (opcode == Opcodes.GETFIELD || opcode == Opcodes.PUTFIELD) {
+                pops++
+            }
+            if (opcode == Opcodes.PUTFIELD || opcode == Opcodes.PUTSTATIC) {
+                pops += fieldSize
+            } else {
+                pushes += fieldSize
+            }
+            StackMetadata(pops, pushes)
+        }
+        is MethodInsnNode -> {
+            val argumentsAndReturnSizes = Type.getArgumentsAndReturnSizes(desc)
+            val pushes = argumentsAndReturnSizes and 0x3
+            var pops = argumentsAndReturnSizes shr 2
+            if (opcode == Opcodes.INVOKESTATIC) {
+                pops--
+            }
+            StackMetadata(pops, pushes)
         }
-        StackMetadata(pops, pushes)
+        is InvokeDynamicInsnNode -> throw UnsupportedOperationException()
+        is MultiANewArrayInsnNode -> StackMetadata(dims, 1)
+        else -> SIMPLE_OPCODES[opcode] ?: throw IllegalArgumentException()
     }
-    is InvokeDynamicInsnNode -> throw UnsupportedOperationException()
-    is MultiANewArrayInsnNode -> StackMetadata(dims, 1)
-    else -> SIMPLE_OPCODES[opcode] ?: throw IllegalArgumentException()
-}

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

@@ -262,7 +262,7 @@ class ConstantArgTransformer : Transformer() {
             } else if (!insn.pure) {
                 // can't replace instructions with a side effect
                 continue
-            } else if (insn.stackMetadata().pushes != 1) {
+            } else if (insn.stackMetadata.pushes != 1) {
                 // can't replace instructions pushing more than one result
                 continue
             }