- Make Boolean 'true' and 'false' singleton VM isolate objects.

vm/object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 251 matching lines @@
     ASSERT(sentinel_ != NULL);
     return *sentinel_;
   }
   // Value marking that we are transitioning from sentinel, e.g., computing
   // a field value. Used to detect circular initialization.
   static const Instance& transition_sentinel() {
     ASSERT(transition_sentinel_ != NULL);
     return *transition_sentinel_;
   }
 
+  static const Bool& bool_true() {
+    ASSERT(bool_true_ != NULL);
+    return *bool_true_;
+  }
+  static const Bool& bool_false() {
+    ASSERT(bool_false_ != NULL);
+    return *bool_false_;
+  }
+
   static RawClass* class_class() { return class_class_; }
   static RawClass* null_class() { return null_class_; }
   static RawClass* dynamic_class() { return dynamic_class_; }
   static RawClass* void_class() { return void_class_; }
   static RawClass* unresolved_class_class() { return unresolved_class_class_; }
   static RawClass* type_arguments_class() { return type_arguments_class_; }
   static RawClass* instantiated_type_arguments_class() {
       return instantiated_type_arguments_class_;
   }
   static RawClass* patch_class_class() { return patch_class_class_; }
@@ skipping 164 matching lines @@
   static RawClass* api_error_class_;  // Class of ApiError.
   static RawClass* language_error_class_;  // Class of LanguageError.
   static RawClass* unhandled_exception_class_;  // Class of UnhandledException.
   static RawClass* unwind_error_class_;  // Class of UnwindError.
 
   // The static values below are read-only handle pointers for singleton
   // objects that are shared between the different isolates.
   static Array* empty_array_;
   static Instance* sentinel_;
   static Instance* transition_sentinel_;
+  static Bool* bool_true_;
+  static Bool* bool_false_;
 
   friend void ClassTable::Register(const Class& cls);
   friend void RawObject::Validate(Isolate* isolate) const;
   friend class Closure;
   friend class SnapshotReader;
   friend class OneByteString;
   friend class TwoByteString;
   friend class ExternalOneByteString;
   friend class ExternalTwoByteString;
 
@@ skipping 3921 matching lines @@
 class Bool : public Instance {
  public:
   bool value() const {
     return raw_ptr()->value_;
   }
 
   static intptr_t InstanceSize() {
     return RoundedAllocationSize(sizeof(RawBool));
   }
 
-  static RawBool* True();
-  static RawBool* False();
+  static const Bool& True() {
+    return Object::bool_true();
+  }
+
+  static const Bool& False() {
+    return Object::bool_false();
+  }
 
   static RawBool* Get(bool value) {
-    return value ? Bool::True() : Bool::False();
+    return value ? Bool::True().raw() : Bool::False().raw();
   }
 
  private:
   void set_value(bool value) const { raw_ptr()->value_ = value; }
 
   // New should only be called to initialize the two legal bool values.
   static RawBool* New(bool value);
 
   HEAP_OBJECT_IMPLEMENTATION(Bool, Instance);
   friend class Class;
@@ skipping 1800 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_