Use NeedsContext() instead of comparing num_heap_slots().

src/full-codegen/x64/full-codegen-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 140 matching lines @@
       // Emit the remaining pushes.
       for (int i  = 0; i < remaining; i++) {
         __ Push(rax);
       }
     }
   }
 
   bool function_in_register = true;
 
   // Possibly allocate a local context.
-  if (info->scope()->num_heap_slots() > 0) {
+  if (info->scope()->NeedsContext()) {
     Comment cmnt(masm_, "[ Allocate context");
     bool need_write_barrier = true;
     int slots = info->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
     // Argument to NewContext is the function, which is still in rdi.
     if (info->scope()->is_script_scope()) {
       __ Push(rdi);
       __ Push(info->scope()->GetScopeInfo(info->isolate()));
       __ CallRuntime(Runtime::kNewScriptContext);
       PrepareForBailoutForId(BailoutId::ScriptContext(),
                              BailoutState::TOS_REGISTER);
@@ skipping 984 matching lines @@
 }
 
 
 MemOperand FullCodeGenerator::ContextSlotOperandCheckExtensions(Variable* var,
                                                                 Label* slow) {
   DCHECK(var->IsContextSlot());
   Register context = rsi;
   Register temp = rbx;
 
   for (Scope* s = scope(); s != var->scope(); s = s->outer_scope()) {
-    if (s->num_heap_slots() > 0) {
+    if (s->NeedsContext()) {
       if (s->calls_sloppy_eval()) {
         // Check that extension is "the hole".
         __ JumpIfNotRoot(ContextOperand(context, Context::EXTENSION_INDEX),
                          Heap::kTheHoleValueRootIndex, slow);
       }
       __ movp(temp, ContextOperand(context, Context::PREVIOUS_INDEX));
       // Walk the rest of the chain without clobbering rsi.
       context = temp;
     }
   }
@@ skipping 2458 matching lines @@
   DCHECK_EQ(
       isolate->builtins()->OnStackReplacement()->entry(),
       Assembler::target_address_at(call_target_address, unoptimized_code));
   return ON_STACK_REPLACEMENT;
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64