Fix race in GC sweeper and isolate reload rollback.

runtime/vm/isolate.h

 // Copyright (c) 2013, 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_ISOLATE_H_
 #define VM_ISOLATE_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/atomic.h"
@@ skipping 537 matching lines @@
 
   // In precompilation we finalize all regular classes before compiling.
   bool all_classes_finalized() const { return all_classes_finalized_; }
   void set_all_classes_finalized(bool value) {
     all_classes_finalized_ = value;
   }
 
   // True during top level parsing.
   bool IsTopLevelParsing() {
     const intptr_t value =
-        AtomicOperations::LoadRelaxedIntPtr(&top_level_parsing_count_);
+        AtomicOperations::LoadRelaxed(&top_level_parsing_count_);
     ASSERT(value >= 0);
     return value > 0;
   }
 
   void IncrTopLevelParsingCount() {
     AtomicOperations::IncrementBy(&top_level_parsing_count_, 1);
   }
   void DecrTopLevelParsingCount() {
     AtomicOperations::DecrementBy(&top_level_parsing_count_, 1);
   }
 
   static const intptr_t kInvalidGen = 0;
 
   void IncrLoadingInvalidationGen() {
     AtomicOperations::IncrementBy(&loading_invalidation_gen_, 1);
     if (loading_invalidation_gen_ == kInvalidGen) {
       AtomicOperations::IncrementBy(&loading_invalidation_gen_, 1);
     }
   }
   intptr_t loading_invalidation_gen() {
-    return AtomicOperations::LoadRelaxedIntPtr(&loading_invalidation_gen_);
+    return AtomicOperations::LoadRelaxed(&loading_invalidation_gen_);
   }
 
   // Used by background compiler which field became boxed and must trigger
   // deoptimization in the mutator thread.
   void AddDeoptimizingBoxedField(const Field& field);
   // Returns Field::null() if none available in the list.
   RawField* GetDeoptimizingBoxedField();
 
 #ifndef PRODUCT
   RawObject* InvokePendingServiceExtensionCalls();
@@ skipping 400 matching lines @@
   intptr_t* spawn_count_;
 
   Dart_IsolateFlags isolate_flags_;
   bool paused_;
   bool errors_are_fatal_;
 };
 
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_