Reapply "Improve hashCode for closure objects" with fixes.

runtime/vm/raw_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 RUNTIME_VM_RAW_OBJECT_H_
 #define RUNTIME_VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/atomic.h"
 #include "vm/exceptions.h"
@@ skipping 901 matching lines @@
   RawObject** from() {
     return reinterpret_cast<RawObject**>(&ptr()->context_scope_);
   }
   RawContextScope* context_scope_;
   RawFunction* parent_function_;  // Enclosing function of this local function.
   RawType* signature_type_;
   RawInstance* closure_;  // Closure object for static implicit closures.
   RawObject** to_snapshot() {
     return reinterpret_cast<RawObject**>(&ptr()->closure_);
   }
-  RawObject* hash_;
-  RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->hash_); }
+  RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->closure_); }
 
   friend class Function;
 };
 
 class RawSignatureData : public RawObject {
  private:
   RAW_HEAP_OBJECT_IMPLEMENTATION(SignatureData);
 
   RawObject** from() {
     return reinterpret_cast<RawObject**>(&ptr()->parent_function_);
@@ skipping 858 matching lines @@
 };
 
 class RawClosure : public RawInstance {
  private:
   RAW_HEAP_OBJECT_IMPLEMENTATION(Closure);
 
   RawObject** from() {
     return reinterpret_cast<RawObject**>(&ptr()->instantiator_type_arguments_);
   }
 
-  // No instance fields should be declared before the following 4 fields whose
+  // No instance fields should be declared before the following fields whose
   // offsets must be identical in Dart and C++.
 
-  // These 4 fields are also declared in the Dart source of class _Closure.
+  // The following fields are also declared in the Dart source of class
+  // _Closure.
   RawTypeArguments* instantiator_type_arguments_;
   RawTypeArguments* function_type_arguments_;
   RawFunction* function_;
   RawContext* context_;
+  RawSmi* hash_;
 
-  RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->context_); }
+  RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->hash_); }
 
   // Note that instantiator_type_arguments_ and function_type_arguments_ are
   // used to instantiate the signature of function_ when this closure is
   // involved in a type test. In other words, these fields define the function
   // type of this closure instance, but they are not used when invoking it.
   // If this closure is generic, it can be invoked with function type arguments
   // that will be processed in the prolog of the closure function_. For example,
   // if the generic closure function_ has a generic parent function, the
   // passed-in function type arguments get concatenated to the function type
   // arguments of the parent that are found in the context_.
@@ skipping 611 matching lines @@
   COMPILE_ASSERT(kExternalTypedDataInt8ArrayCid ==
                  kTypedDataInt8ArrayViewCid + 15);
   COMPILE_ASSERT(kByteBufferCid == kExternalTypedDataInt8ArrayCid + 14);
   COMPILE_ASSERT(kNullCid == kByteBufferCid + 1);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_RAW_OBJECT_H_