Use range information for optimizing integer boxing and fix bug in range analysis.

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 5008 matching lines @@
   static RawClass* Class();
 
   static intptr_t Value(const RawSmi* raw_smi) {
     return ValueFromRaw(reinterpret_cast<uword>(raw_smi));
   }
 
   static intptr_t RawValue(intptr_t value) {
     return reinterpret_cast<intptr_t>(New(value));
   }
 
-  static bool IsValid(intptr_t value) {
-    return (value >= kMinValue) && (value <= kMaxValue);
-  }
-
-  static bool IsValid64(int64_t value) {
-    return (value >= kMinValue) && (value <= kMaxValue);
+  template <typename T>
+  static bool IsValid(T value) {
+    COMPILE_ASSERT(sizeof(kMinValue) == sizeof(kMaxValue));
+    if (sizeof(value) < sizeof(kMinValue)) {

[Vyacheslav Egorov (Google), 2014/06/24 12:18:12]

We also need to check that it is integral type because on x64 sizeof(float) <
sizeof(intptr_t).

std::numeric_limits<T>::is_integer

[Florian Schneider, 2014/06/24 12:35:06]

Done. Added a COMPILE_ASSERT because we should never invoke it with a
non-integral type.

+      return true;
+    }
+    if (static_cast<T>(-1) < 0) {

[Vyacheslav Egorov (Google), 2014/06/24 12:18:12]

I would really prefer we write C++ here:

std::numeric_limits<T>::is_signed

[Florian Schneider, 2014/06/24 12:35:06]

Done.

+      return (value >= static_cast<T>(kMinValue))
+          && (value <= static_cast<T>(kMaxValue));
+    } else {
+      return value <= static_cast<T>(kMaxValue);
+    }
   }
 
   RawInteger* ShiftOp(Token::Kind kind,
                       const Smi& other,
                       const bool silent = false) const;
 
   void operator=(RawSmi* value) {
     raw_ = value;
     CHECK_HANDLE();
   }
@@ skipping 2084 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_