Performance improvement for the Dart VM runtime method

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
===================================================================
--- runtime/vm/raw_object.h	(revision 11476)
+++ runtime/vm/raw_object.h	(working copy)
@@ -1123,10 +1123,18 @@
 };
 
 
+DART_EXTERN_C {
+  Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle, void**);
+  Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle, void**);
+  Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle, void**);
+}
+
+
 class RawExternalOneByteString : public RawString {
   RAW_HEAP_OBJECT_IMPLEMENTATION(ExternalOneByteString);
 
   ExternalStringData<uint8_t>* external_data_;
+  friend Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle o, void**);

[Ivan Posva, 2012/08/28 22:21:20]

Please remove the o to be consistent.
Also can you avoid the above block declaration of the functions being friended?

[Tom Ball, 2012/08/29 00:16:39]

The 'o' is removed, but I think the block declaration is needed, because
otherwise the compiler reports:

error: previous declaration of ‘_Dart_Handle*
dart::Dart_ExternalStringGetPeer(Dart_Handle, void**)’ with ‘C++’ linkage

I tried removing the block and using ::Dart_ExternalStringGetPeer(...) in the
friend statement, since the classes are in the dart namespace but the API
functions aren't, but that failed with:


../runtime/vm/raw_object.h:1129:32: error: ‘dart::ExternalStringData<unsigned
char>* dart::RawExternalOneByteString::external_data_’ is private
../runtime/vm/dart_api_impl.cc:1541:55: error: within this context

Any ideas?

 };
 
 
@@ -1134,6 +1142,7 @@
   RAW_HEAP_OBJECT_IMPLEMENTATION(ExternalTwoByteString);
 
   ExternalStringData<uint16_t>* external_data_;
+  friend Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle, void**);
 };
 
 
@@ -1141,6 +1150,7 @@
   RAW_HEAP_OBJECT_IMPLEMENTATION(ExternalFourByteString);
 
   ExternalStringData<uint32_t>* external_data_;
+  friend Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle, void**);
 };