add debug mode

vm/src/main/kotlin/gay/pizza/pork/vm/InternalMachine.kt

@@ -4,7 +4,7 @@ import gay.pizza.pork.bytecode.CompiledWorld
 import gay.pizza.pork.bytecode.ConstantTag
 import gay.pizza.pork.execution.NativeRegistry
 
-class InternalMachine(val world: CompiledWorld, val nativeRegistry: NativeRegistry, val handlers: List<OpHandler>) {
+class InternalMachine(val world: CompiledWorld, val nativeRegistry: NativeRegistry, val handlers: List<OpHandler>, val debug: Boolean = false) {
   private val inlined = world.code.map { op ->
     val handler = handlers.firstOrNull { it.code == op.code }
       ?: throw VirtualMachineException("Opcode ${op.code.name} does not have a handler.")
@@ -23,6 +23,11 @@ class InternalMachine(val world: CompiledWorld, val nativeRegistry: NativeRegist
 
   fun step(): Boolean {
     val (op, handler) = inlined[inst.toInt()]
+    if (debug) {
+      val frame = frame(inst)
+      println("vm: step: in ${frame?.symbolInfo?.commonSymbolIdentity ?: "unknown"}: $inst ${op.code}${if (op.args.isEmpty()) "" else " " + op.args.joinToString(" ")}")
+    }
+
     handler.handle(this, op)
     if (autoNextInst) {
       inst++
@@ -32,19 +37,29 @@ class InternalMachine(val world: CompiledWorld, val nativeRegistry: NativeRegist
   }
 
   fun pushScope() {
+    if (debug) {
+      println("  vm: push scope")
+    }
     locals.add(LocalSlots())
   }
 
   fun popScope() {
+    if (debug) {
+      println("  vm: pop scope")
+    }
     locals.removeLast()
   }
 
   fun loadConstant(id: UInt) {
     val constant = world.constantPool.constants[id.toInt()]
-    when (constant.tag) {
-      ConstantTag.String -> push(String(constant.value))
+    val value = when (constant.tag) {
+      ConstantTag.String -> String(constant.value)
       else -> throw VirtualMachineException("Unknown constant tag: ${constant.tag.name}")
     }
+    if (debug) {
+      println("  vm: load constant: ${constant.id} ${constant.tag.name} $value")
+    }
+    push(value)
   }
 
   fun localAt(id: UInt): Any {
@@ -53,35 +68,57 @@ class InternalMachine(val world: CompiledWorld, val nativeRegistry: NativeRegist
   }
 
   fun loadLocal(id: UInt) {
-    push(localAt(id))
+    val value = localAt(id)
+    if (debug) {
+      println("  vm: load local: $id   $value")
+    }
+    push(value)
   }
 
   fun storeLocal(id: UInt) {
     val localSet = locals.last()
     val value = popAnyValue()
+    if (debug) {
+      println("  vm: store local: $id = $value")
+    }
     localSet.store(id, value)
   }
 
   fun setNextInst(value: UInt) {
     inst = value
     autoNextInst = false
+    if (debug) {
+      println("  vm: next instruction: $value")
+    }
   }
 
   fun pushReturnAddress(value: UInt) {
+    if (debug) {
+      println("  vm: push return address: $value")
+    }
     returnAddressStack.add(value)
   }
 
   fun pushCallStack(value: UInt) {
+    if (debug) {
+      println("  vm: push call stack: $value")
+    }
     callStack.add(value)
   }
 
   fun popCallStack() {
-    callStack.removeLast()
+    val call = callStack.removeLast()
+    if (debug) {
+      println("  vm: pop call stack: $call")
+    }
   }
 
   fun armReturnAddressIfSet() {
     val returnAddress = returnAddressStack.removeLastOrNull()
     if (returnAddress != null) {
+      if (debug) {
+        println("  vm: arm return address: $returnAddress")
+      }
       setNextInst(returnAddress)
     } else {
       exit()
@@ -89,18 +126,33 @@ class InternalMachine(val world: CompiledWorld, val nativeRegistry: NativeRegist
   }
 
   fun push(item: Any) {
+    if (debug) {
+      println("  vm: push stack: $item")
+    }
     stack.add(item)
   }
 
-  fun popAnyValue(): Any = stack.removeLast()
+  fun popAnyValue(): Any {
+    val value = stack.removeLast()
+    if (debug) {
+      println("  vm: pop stack: $value")
+    }
+    return value
+  }
 
   inline fun <reified T> pop(): T = popAnyValue() as T
 
   fun exit() {
+    if (debug) {
+      println("  vm: exit")
+    }
     exitFlag = true
   }
 
   fun reset() {
+    if (debug) {
+      println("vm: reset")
+    }
     stack.clear()
     callStack.clear()
     callStack.add(0u)

vm/src/main/kotlin/gay/pizza/pork/vm/VirtualMachine.kt

@@ -4,11 +4,12 @@ import gay.pizza.pork.bytecode.CompiledWorld
 import gay.pizza.pork.execution.ExecutionContext
 import gay.pizza.pork.execution.NativeRegistry
 
-class VirtualMachine(world: CompiledWorld, nativeRegistry: NativeRegistry) : ExecutionContext {
+class VirtualMachine(world: CompiledWorld, nativeRegistry: NativeRegistry, debug: Boolean = false) : ExecutionContext {
   private val internal = InternalMachine(
     world = world,
     nativeRegistry = nativeRegistry,
-    handlers = StandardOpHandlers
+    handlers = StandardOpHandlers,
+    debug = debug,
   )
 
   override fun execute() {

vm/src/main/kotlin/gay/pizza/pork/vm/VirtualMachineProvider.kt

@@ -4,18 +4,18 @@ import gay.pizza.pork.ast.gen.Symbol
 import gay.pizza.pork.compiler.Compiler
 import gay.pizza.pork.execution.ExecutionContext
 import gay.pizza.pork.execution.ExecutionContextProvider
-import gay.pizza.pork.execution.NativeRegistry
+import gay.pizza.pork.execution.ExecutionOptions
 import gay.pizza.pork.frontend.ImportLocator
 import gay.pizza.pork.frontend.World
 
 class VirtualMachineProvider(val world: World) : ExecutionContextProvider {
-  override fun prepare(importLocator: ImportLocator, entryPointSymbol: Symbol, nativeRegistry: NativeRegistry): ExecutionContext {
+  override fun prepare(importLocator: ImportLocator, entryPointSymbol: Symbol, options: ExecutionOptions): ExecutionContext {
     val compiler = Compiler(world)
     val slab = world.load(importLocator)
     val compilableSlab = compiler.compilableSlabs.of(slab)
     val compilableSymbol = compilableSlab.resolve(entryPointSymbol) ?:
       throw RuntimeException("Unable to find compilable symbol for entry point '${entryPointSymbol.id}'")
     val compiledWorld = compiler.compile(compilableSymbol)
-    return VirtualMachine(compiledWorld, nativeRegistry)
+    return VirtualMachine(world = compiledWorld, nativeRegistry = options.nativeRegistry, debug = options.debug)
   }
 }