Split the virtual frame into heavy and light versions....

src/arm/virtual-frame-arm.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 31 matching lines @@
 }
 
 
 void VirtualFrame::SyncElementByPushing(int index) {
   UNREACHABLE();
 }
 
 
 void VirtualFrame::SyncRange(int begin, int end) {
   // All elements are in memory on ARM (ie, synced).
-#ifdef DEBUG
-  for (int i = begin; i <= end; i++) {
-    ASSERT(elements_[i].is_synced());
-  }
-#endif
 }
 
 
 void VirtualFrame::MergeTo(VirtualFrame* expected) {
   // ARM frames are currently always in memory.
   ASSERT(Equals(expected));
 }
 
 
 void VirtualFrame::MergeMoveRegistersToMemory(VirtualFrame* expected) {
@@ skipping 196 matching lines @@
   int num_virtual_elements = (element_count() - 1) - stack_pointer_;
 
   // Emit code to lower the stack pointer if necessary.
   if (num_virtual_elements < count) {
     int num_dropped = count - num_virtual_elements;
     stack_pointer_ -= num_dropped;
     __ add(sp, sp, Operand(num_dropped * kPointerSize));
   }
 
   // Discard elements from the virtual frame and free any registers.
-  for (int i = 0; i < count; i++) {
-    FrameElement dropped = elements_.RemoveLast();
-    if (dropped.is_register()) {
-      Unuse(dropped.reg());
-    }
-  }
+  element_count_ -= count;
 }
 
 
 Result VirtualFrame::Pop() {
   UNIMPLEMENTED();
   return Result();
 }
 
 
 void VirtualFrame::EmitPop(Register reg) {
   ASSERT(stack_pointer_ == element_count() - 1);
   stack_pointer_--;
-  elements_.RemoveLast();
+  element_count_--;
   __ pop(reg);
 }
 
 
 void VirtualFrame::EmitPush(Register reg) {
   ASSERT(stack_pointer_ == element_count() - 1);
-  elements_.Add(FrameElement::MemoryElement(NumberInfo::Unknown()));
+  element_count_++;
   stack_pointer_++;
   __ push(reg);
 }
 
 
 void VirtualFrame::EmitPushMultiple(int count, int src_regs) {
   ASSERT(stack_pointer_ == element_count() - 1);
   Adjust(count);
   __ stm(db_w, sp, src_regs);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal