Use a loop in generated code to allocate stack slots for function with many l...

src/x64/virtual-frame-x64.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 182 matching lines @@
   // 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.  This
   // avoids generating unnecessary merge code when jumping to the
   // shared return site.  Emits code for spills.
   void PrepareForReturn();
 
+  // Number of local variables after when we use a loop for allocating.
+  static const int kLocalVarBound = 7;
+
   // Allocate and initialize the frame-allocated locals.
   void AllocateStackSlots();
 
   // An element of the expression stack as an assembly operand.
   Operand ElementAt(int index) const {
     return Operand(rsp, index * kPointerSize);
   }
 
   // Random-access store to a frame-top relative frame element.  The result
   // becomes owned by the frame and is invalidated.
@@ skipping 335 matching lines @@
 
   // Classes that need raw access to the elements_ array.
   friend class DeferredCode;
   friend class JumpTarget;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_VIRTUAL_FRAME_X64_H_