Reworked previous CL (ExternalStringGetPeer speed up) to avoid the

runtime/vm/dart_api_impl.cc

 // 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.
 
 #include "include/dart_api.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
@@ skipping 1515 matching lines @@
 }
 
 
 DART_EXPORT Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle object,
                                                    void** peer) {
   intptr_t class_id = Api::ClassId(object);
   if (peer == NULL) {
     RETURN_NULL_ERROR(peer);
   } else {
     NoGCScope no_gc_scope;
-    RawObject* raw_obj = Api::UnwrapHandle(object);
+    uword raw_addr = RawObject::ToAddr(Api::UnwrapHandle(object));
     switch (class_id) {
       case kExternalOneByteStringCid: {
         RawExternalOneByteString* raw_string =
-            reinterpret_cast<RawExternalOneByteString*>(raw_obj)->ptr();
-        ExternalStringData<uint8_t>* data = raw_string->external_data_;
-        *peer = data->peer();
+            reinterpret_cast<RawExternalOneByteString*>(raw_addr);
+        *peer = raw_string->peer();
         return Api::Success(Isolate::Current());
       }
       case kExternalTwoByteStringCid: {
         RawExternalTwoByteString* raw_string =
-            reinterpret_cast<RawExternalTwoByteString*>(raw_obj)->ptr();
-        ExternalStringData<uint16_t>* data = raw_string->external_data_;
-        *peer = data->peer();
+            reinterpret_cast<RawExternalTwoByteString*>(raw_addr);
+        *peer = raw_string->peer();
         return Api::Success(Isolate::Current());
       }
       case kExternalFourByteStringCid: {
         RawExternalFourByteString* raw_string =
-            reinterpret_cast<RawExternalFourByteString*>(raw_obj)->ptr();
-        ExternalStringData<uint32_t>* data = raw_string->external_data_;
-        *peer = data->peer();
+            reinterpret_cast<RawExternalFourByteString*>(raw_addr);
+        *peer = raw_string->peer();
         return Api::Success(Isolate::Current());
       }
     }
   }
 
   // It's not an external string, return appropriate error.
   // Note: this is invoked outside of the NoGCScope'd block above, since
   // error messages allocate new handles.
   if (!RawObject::IsStringClassId(class_id)) {
     RETURN_TYPE_ERROR(Isolate::Current(), object, String);
@@ skipping 2612 matching lines @@
 DART_EXPORT void Dart_InitPerfEventsSupport(Dart_FileWriterFunction function) {
   Dart::set_perf_events_writer(function);
 }
 
 
 DART_EXPORT void Dart_InitFlowGraphPrinting(Dart_FileWriterFunction function) {
   Dart::set_flow_graph_writer(function);
 }
 
 }  // namespace dart