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

src/arm/virtual-frame-arm.h

 // 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 49 matching lines @@
 
   // Construct an initial virtual frame on entry to a JS function.
   inline VirtualFrame();
 
   // Construct a virtual frame as a clone of an existing one.
   explicit inline VirtualFrame(VirtualFrame* original);
 
   CodeGenerator* cgen() { return CodeGeneratorScope::Current(); }
   MacroAssembler* masm() { return cgen()->masm(); }
 
-  // Create a duplicate of an existing valid frame element.
-  FrameElement CopyElementAt(int index,
-                             NumberInfo info = NumberInfo::Unknown());
-
   // The number of elements on the virtual frame.
-  int element_count() { return elements_.length(); }
+  int element_count() { return element_count_; }
 
   // The height of the virtual expression stack.
   int height() {
     return element_count() - expression_base_index();
   }
 
   int register_location(int num) {
     ASSERT(num >= 0 && num < RegisterAllocator::kNumRegisters);
     return register_locations_[num];
   }
@@ skipping 22 matching lines @@
   void Adjust(int count);
 
   // Forget elements from the top of the frame to match an actual frame (eg,
   // the frame after a runtime call).  No code is emitted.
   void Forget(int count) {
     ASSERT(count >= 0);
     ASSERT(stack_pointer_ == element_count() - 1);
     stack_pointer_ -= count;
     // On ARM, all elements are in memory, so there is no extra bookkeeping
     // (registers, copies, etc.) beyond dropping the elements.
-    elements_.Rewind(stack_pointer_ + 1);
+    element_count_ -= count;
   }
 
   // Forget count elements from the top of the frame and adjust the stack
   // pointer downward.  This is used, for example, before merging frames at
   // break, continue, and return targets.
   void ForgetElements(int count);
 
   // Spill all values from the frame to memory.
-  void SpillAll();
+  inline void SpillAll();
 
   // Spill all occurrences of a specific register from the frame.
   void Spill(Register reg) {
     if (is_used(reg)) SpillElementAt(register_location(reg));
   }
 
   // Spill all occurrences of an arbitrary register if possible.  Return the
   // register spilled or no_reg if it was not possible to free any register
   // (ie, they all have frame-external references).
   Register SpillAnyRegister();
@@ skipping 34 matching lines @@
   // calling Enter, the virtual frame is ready for use; and after calling
   // Exit it should not be used.  Note that Enter does not allocate space in
   // the physical frame for storing frame-allocated locals.
   void Enter();
   void Exit();
 
   // Prepare for returning from the frame by spilling locals and
   // dropping all non-locals elements in the virtual frame.  This
   // avoids generating unnecessary merge code when jumping to the
   // shared return site.  Emits code for spills.
-  void PrepareForReturn();
+  inline void PrepareForReturn();
 
   // Number of local variables after when we use a loop for allocating.
   static const int kLocalVarBound = 5;
 
   // Allocate and initialize the frame-allocated locals.
   void AllocateStackSlots();
 
   // The current top of the expression stack as an assembly operand.
   MemOperand Top() { return MemOperand(sp, 0); }
 
   // An element of the expression stack as an assembly operand.
   MemOperand ElementAt(int index) {
     return MemOperand(sp, index * kPointerSize);
   }
 
   // Random-access store to a frame-top relative frame element.  The result
   // becomes owned by the frame and is invalidated.
   void SetElementAt(int index, Result* value);
 
   // Set a frame element to a constant.  The index is frame-top relative.
   void SetElementAt(int index, Handle<Object> value) {
     Result temp(value);
     SetElementAt(index, &temp);
   }
 
-  void PushElementAt(int index) {
-    PushFrameSlotAt(element_count() - index - 1);
-  }
-
   // A frame-allocated local as an assembly operand.
   MemOperand LocalAt(int index) {
     ASSERT(0 <= index);
     ASSERT(index < local_count());
     return MemOperand(fp, kLocal0Offset - index * kPointerSize);
   }
 
-  // Push a copy of the value of a local frame slot on top of the frame.
-  void PushLocalAt(int index) {
-    PushFrameSlotAt(local0_index() + index);
-  }
-
   // Push the value of a local frame slot on top of the frame and invalidate
   // the local slot.  The slot should be written to before trying to read
   // from it again.
   void TakeLocalAt(int index) {
     TakeFrameSlotAt(local0_index() + index);
   }
 
-  // Store the top value on the virtual frame into a local frame slot.  The
-  // value is left in place on top of the frame.
-  void StoreToLocalAt(int index) {
-    StoreToFrameSlotAt(local0_index() + index);
-  }
-
   // Push the address of the receiver slot on the frame.
   void PushReceiverSlotAddress();
 
   // The function frame slot.
   MemOperand Function() { return MemOperand(fp, kFunctionOffset); }
 
-  // Push the function on top of the frame.
-  void PushFunction() { PushFrameSlotAt(function_index()); }
-
   // The context frame slot.
   MemOperand Context() { return MemOperand(fp, kContextOffset); }
 
   // Save the value of the esi register to the context frame slot.
   void SaveContextRegister();
 
   // Restore the esi register from the value of the context frame
   // slot.
   void RestoreContextRegister();
 
   // A parameter as an assembly operand.
   MemOperand ParameterAt(int index) {
     // Index -1 corresponds to the receiver.
     ASSERT(-1 <= index);  // -1 is the receiver.
     ASSERT(index <= parameter_count());
     return MemOperand(fp, (1 + parameter_count() - index) * kPointerSize);
   }
 
-  // Push a copy of the value of a parameter frame slot on top of the frame.
-  void PushParameterAt(int index) {
-    PushFrameSlotAt(param0_index() + index);
-  }
-
   // Push the value of a paramter frame slot on top of the frame and
   // invalidate the parameter slot.  The slot should be written to before
   // trying to read from it again.
   void TakeParameterAt(int index) {
     TakeFrameSlotAt(param0_index() + index);
   }
 
   // Store the top value on the virtual frame into a parameter frame slot.
   // The value is left in place on top of the frame.
   void StoreToParameterAt(int index) {
@@ skipping 37 matching lines @@
                       int dropped_args);
 
   // Drop a number of elements from the top of the expression stack.  May
   // emit code to affect the physical frame.  Does not clobber any registers
   // excepting possibly the stack pointer.
   void Drop(int count);
 
   // Drop one element.
   void Drop() { Drop(1); }
 
-  // Duplicate the top element of the frame.
-  void Dup() { PushFrameSlotAt(element_count() - 1); }
-
   // Pop an element from the top of the expression stack.  Returns a
   // Result, which may be a constant or a register.
   Result Pop();
 
   // Pop and save an element from the top of the expression stack and
   // emit a corresponding pop instruction.
   void EmitPop(Register reg);
 
   // Push an element on top of the expression stack and emit a
   // corresponding push instruction.
   void EmitPush(Register reg);
 
   // Push multiple registers on the stack and the virtual frame
   // Register are selected by setting bit in src_regs and
   // are pushed in decreasing order: r15 .. r0.
   void EmitPushMultiple(int count, int src_regs);
 
   // Push an element on the virtual frame.
-  inline void Push(Register reg, NumberInfo info = NumberInfo::Unknown());
   inline void Push(Handle<Object> value);
   inline void Push(Smi* value);
 
-  // Pushing a result invalidates it (its contents become owned by the frame).
-  void Push(Result* result) {
-    if (result->is_register()) {
-      Push(result->reg());
-    } else {
-      ASSERT(result->is_constant());
-      Push(result->handle());
-    }
-    result->Unuse();
-  }
-
   // Nip removes zero or more elements from immediately below the top
   // of the frame, leaving the previous top-of-frame value on top of
   // the frame.  Nip(k) is equivalent to x = Pop(), Drop(k), Push(x).
   inline void Nip(int num_dropped);
 
   inline void SetTypeForLocalAt(int index, NumberInfo info);
   inline void SetTypeForParamAt(int index, NumberInfo info);
 
  private:
   static const int kLocal0Offset = JavaScriptFrameConstants::kLocal0Offset;
   static const int kFunctionOffset = JavaScriptFrameConstants::kFunctionOffset;
   static const int kContextOffset = StandardFrameConstants::kContextOffset;
 
   static const int kHandlerSize = StackHandlerConstants::kSize / kPointerSize;
   static const int kPreallocatedElements = 5 + 8;  // 8 expression stack slots.
 
-  ZoneList<FrameElement> elements_;
+  int element_count_;
 
   // The index of the element that is at the processor's stack pointer
   // (the sp register).
   int stack_pointer_;
 
   // The index of the register frame element using each register, or
   // kIllegalIndex if a register is not on the frame.
   int register_locations_[RegisterAllocator::kNumRegisters];
 
   // The number of frame-allocated locals and parameters respectively.
@@ skipping 62 matching lines @@
 
   // Sync the range of elements in [begin, end] with memory.
   void SyncRange(int begin, int end);
 
   // Sync a single unsynced element that lies beneath or at the stack pointer.
   void SyncElementBelowStackPointer(int index);
 
   // Sync a single unsynced element that lies just above the stack pointer.
   void SyncElementByPushing(int index);
 
-  // Push a copy of a frame slot (typically a local or parameter) on top of
-  // the frame.
-  inline void PushFrameSlotAt(int index);
-
   // Push a the value of a frame slot (typically a local or parameter) on
   // top of the frame and invalidate the slot.
   void TakeFrameSlotAt(int index);
 
   // Store the value on top of the frame to a frame slot (typically a local
   // or parameter).
   void StoreToFrameSlotAt(int index);
 
   // Spill all elements in registers. Spill the top spilled_args elements
   // on the frame.  Sync all other frame elements.
@@ skipping 23 matching lines @@
 
   // Invalidates a frame slot (puts an invalid frame element in it).
   // Copies on the frame are correctly handled, and if this slot was
   // the backing store of copies, the index of the new backing store
   // is returned.  Otherwise, returns kIllegalIndex.
   // Register counts are correctly updated.
   int InvalidateFrameSlotAt(int index);
 
   inline bool Equals(VirtualFrame* other);
 
-  // Classes that need raw access to the elements_ array.
+  friend class JumpTarget;
   friend class DeferredCode;
-  friend class JumpTarget;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_VIRTUAL_FRAME_ARM_H_