Add thread safe constant canonicalization.

runtime/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 1183 matching lines @@
   RawFunction* LookupFunction(const String& name) const;
   RawFunction* LookupFunctionAllowPrivate(const String& name) const;
   RawFunction* LookupGetterFunction(const String& name) const;
   RawFunction* LookupSetterFunction(const String& name) const;
   RawField* LookupInstanceField(const String& name) const;
   RawField* LookupStaticField(const String& name) const;
   RawField* LookupField(const String& name) const;
 
   RawLibraryPrefix* LookupLibraryPrefix(const String& name) const;
 
+  // Returns an instance of Double or Double::null().
+  // 'index' points to either:
+  // - constants_list_ position of found element, or
+  // - constants_list_ position where new canonical can be inserted.
+  RawDouble* LookupCanonicalDouble(Zone* zone,
+                                   double value, intptr_t* index) const;
+  RawMint* LookupCanonicalMint(Zone* zone,
+                               int64_t value, intptr_t* index) const;
+  RawBigint* LookupCanonicalBigint(Zone* zone,
+                                   const Bigint& value, intptr_t* index) const;
+  // The methods above are more efficient than this generic one.
+  RawInstance* LookupCanonicalInstance(Zone* zone,
+                                       const Instance& value,
+                                       intptr_t* index) const;
+
   void InsertCanonicalConstant(intptr_t index, const Instance& constant) const;
 
   intptr_t FindCanonicalTypeIndex(const AbstractType& needle) const;
   RawAbstractType* CanonicalTypeFromIndex(intptr_t idx) const;
 
   static intptr_t InstanceSize() {
     return RoundedAllocationSize(sizeof(RawClass));
   }
 
   bool is_implemented() const {
@@ skipping 7264 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_