[K/N] Reduce frame size by removing unused arena field.

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/cexport/CAdapterApiExporter.kt

@@ -289,7 +289,6 @@ internal class CAdapterApiExporter(
     |}  // extern "C"
     |
     |struct ${prefix}_FrameOverlay {
-    |  void* arena;
     |  ${prefix}_FrameOverlay* previous;
     |  ${prefix}_KInt parameters;
     |  ${prefix}_KInt count;
@@ -406,4 +405,4 @@ private operator fun String.times(count: Int): String {
 }
 
 private val KotlinType.shortNameForPredefinedType
-    get() = this.toString().split('.').last()
+    get() = this.toString().split('.').last()

kotlin-native/runtime/src/legacymm/cpp/Memory.cpp

@@ -1022,10 +1022,6 @@ inline void traverseContainerReferredObjects(ContainerHeader* container, func pr
   });
 }
 
-inline FrameOverlay* asFrameOverlay(ObjHeader** slot) {
-  return reinterpret_cast<FrameOverlay*>(slot);
-}
-
 inline void lock(KInt* spinlock) {
   while (compareAndSwap(spinlock, 0, 1) != 0) {}
 }
@@ -1763,39 +1759,6 @@ inline void releaseHeapRef(const ObjHeader* header) {
     releaseHeapRef<Strict, CanCollect>(const_cast<ContainerHeader*>(container));
 }
 
-
-// TODO: Consider removing this unused stuff.
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wunused-function"
-
-// We use first slot as place to store frame-local arena container.
-// TODO: create ArenaContainer object on the stack, so that we don't
-// do two allocations per frame (ArenaContainer + actual container).
-inline ArenaContainer* initedArena(ObjHeader** auxSlot) {
-  auto frame = asFrameOverlay(auxSlot);
-  auto arena = reinterpret_cast<ArenaContainer*>(frame->arena);
-  if (!arena) {
-    arena = std_support::allocator_new<ArenaContainer>(objectAllocator);
-    MEMORY_LOG("Initializing arena in %p\n", frame)
-    arena->Init();
-    frame->arena = arena;
-  }
-  return arena;
-}
-
-inline container_size_t containerSize(const ContainerHeader* container) {
-  container_size_t result = 0;
-  const ObjHeader* obj = reinterpret_cast<const ObjHeader*>(container + 1);
-  for (uint32_t object = 0; object < container->objectCount(); object++) {
-    container_size_t size = objectSize(obj);
-    result += size;
-    obj = reinterpret_cast<ObjHeader*>(reinterpret_cast<uintptr_t>(obj) + size);
-  }
-  return result;
-}
-
-#pragma clang diagnostic pop
-
 #if USE_GC
 void incrementStack(MemoryState* state) {
   FrameOverlay* frame = currentFrame;

kotlin-native/runtime/src/main/cpp/Memory.h

@@ -362,7 +362,6 @@ RUNTIME_NOTHROW void DisposeRegularWeakReferenceImpl(ObjHeader* counter);
 #endif
 
 struct FrameOverlay {
-  void* arena;
   FrameOverlay* previous;
   // As they go in pair, sizeof(FrameOverlay) % sizeof(void*) == 0 is always held.
   int32_t parameters;