Better pack fields in Variable

src/ast/variables.cc

 // Copyright 2011 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.
 
 #include "src/ast/variables.h"
 
 #include "src/ast/scopes.h"
 #include "src/globals.h"
 
 namespace v8 {
@@ skipping 15 matching lines @@
   }
   UNREACHABLE();
   return NULL;
 }
 
 Variable::Variable(Scope* scope, const AstRawString* name, VariableMode mode,
                    Kind kind, InitializationFlag initialization_flag,
                    MaybeAssignedFlag maybe_assigned_flag)
     : scope_(scope),
       name_(name),
-      mode_(mode),
-      kind_(kind),
-      location_(VariableLocation::UNALLOCATED),
+      local_if_not_shadowed_(nullptr),
       index_(-1),
       initializer_position_(kNoSourcePosition),
-      local_if_not_shadowed_(NULL),
-      force_context_allocation_(false),
-      is_used_(false),
-      initialization_flag_(initialization_flag),
-      maybe_assigned_(maybe_assigned_flag) {
+      bit_field_(MaybeAssignedFlagField::encode(maybe_assigned_flag) |
+                 InitializationFlagField::encode(initialization_flag) |
+                 VariableModeField::encode(mode) | IsUsedField::encode(false) |
+                 ForceContextAllocationField::encode(false) |
+                 LocationField::encode(VariableLocation::UNALLOCATED) |
+                 KindField::encode(kind)) {
   // Var declared variables never need initialization.
   DCHECK(!(mode == VAR && initialization_flag == kNeedsInitialization));
 }
 
 
 bool Variable::IsGlobalObjectProperty() const {
   // Temporaries are never global, they must always be allocated in the
   // activation frame.
-  return (IsDynamicVariableMode(mode_) ||
-          (IsDeclaredVariableMode(mode_) && !IsLexicalVariableMode(mode_))) &&
+  return (IsDynamicVariableMode(mode()) ||
+          (IsDeclaredVariableMode(mode()) && !IsLexicalVariableMode(mode()))) &&
          scope_ != NULL && scope_->is_script_scope();
 }
 
 
 bool Variable::IsStaticGlobalObjectProperty() const {
   // Temporaries are never global, they must always be allocated in the
   // activation frame.
-  return (IsDeclaredVariableMode(mode_) && !IsLexicalVariableMode(mode_)) &&
+  return (IsDeclaredVariableMode(mode()) && !IsLexicalVariableMode(mode())) &&
          scope_ != NULL && scope_->is_script_scope();
 }
 
 
 int Variable::CompareIndex(Variable* const* v, Variable* const* w) {
   int x = (*v)->index();
   int y = (*w)->index();
   // Consider sorting them according to type as well?
   return x - y;
 }
 
 }  // namespace internal
 }  // namespace v8