Optimize getField by caching a closure generated from a specialized function kind.

runtime/lib/mirrors.cc

Index: runtime/lib/mirrors.cc
diff --git a/runtime/lib/mirrors.cc b/runtime/lib/mirrors.cc
index 3b7391caf42238dba40a43e93faefaf52a13fafe..96d50daf048c39ae704952d7a521601365d4b90f 100644
--- a/runtime/lib/mirrors.cc
+++ b/runtime/lib/mirrors.cc
@@ -1301,6 +1301,83 @@ DEFINE_NATIVE_ENTRY(TypeVariableMirror_upper_bound, 1) {
 }
 
 
+static RawInstance* MakeAccessorClosure(const Class& cls,
+                                        const String& selector,
+                                        RawFunction::Kind kind) {
+  const Error& error = Error::Handle(cls.EnsureIsFinalized(Isolate::Current()));
+  ASSERT(error.IsNull());
+
+  const String& func_name = String::Handle(Symbols::New(selector));
+  const Function& function =
+      Function::Handle(Function::New(func_name,
+                                     kind,
+                                     true,   // Static.
+                                     false,  // Not const.
+                                     false,  // Not abstract.
+                                     false,  // Not external.
+                                     false,  // Not native.
+                                     cls,
+                                     Scanner::kNoSourcePos));
+  const Type& dynamic_type = Type::Handle(Type::DynamicType());
+  function.set_result_type(dynamic_type);
+
+  // 1 - the closure reciever, 2 - the object whose field is to be gotten.
+  intptr_t num_params = (kind == RawFunction::kGetFieldClosure) ? 2 : 3;
+
+  function.set_num_fixed_parameters(num_params);
+  function.set_parameter_types(
+      Array::Handle(Array::New(num_params, Heap::kOld)));
+  function.set_parameter_names(
+      Array::Handle(Array::New(num_params, Heap::kOld)));
+  for (intptr_t i = 0; i < num_params; i++) {
+    function.SetParameterTypeAt(i, dynamic_type);
+    function.SetParameterNameAt(i, Symbols::Other());
+  }
+  function.SetNumOptionalParameters(0, true);
+
+  // Lookup or create a new signature class for the closure function in the
+  // library of the owner class.
+  const Library& library = Library::Handle(cls.library());
+  const String& signature = String::Handle(function.Signature());
+  Class& signature_class = Class::ZoneHandle(
+      library.LookupLocalClass(signature));
+  if (signature_class.IsNull()) {
+    const Script& script = Script::Handle(cls.script());
+    signature_class = Class::NewSignatureClass(signature,
+                                               function,
+                                               script,
+                                               function.token_pos());
+    library.AddClass(signature_class);
+  } else {
+    function.set_signature_class(signature_class);
+  }
+  const Type& signature_type = Type::Handle(signature_class.SignatureType());
+  if (!signature_type.IsFinalized()) {
+    ClassFinalizer::FinalizeType(
+        signature_class, signature_type, ClassFinalizer::kCanonicalize);
+  }
+  ObjectStore* object_store = Isolate::Current()->object_store();
+  const Context& context = Context::Handle(object_store->empty_context());
+  return Closure::New(function, context, Heap::kOld);
+}
+
+
+DEFINE_NATIVE_ENTRY(Mirrors_makeGetter, 2) {
+  GET_NON_NULL_NATIVE_ARGUMENT(String, selector, arguments->NativeArgAt(0));
+  GET_NON_NULL_NATIVE_ARGUMENT(Type, scratch_type, arguments->NativeArgAt(1));
+  const Class& cls = Class::Handle(scratch_type.type_class());
+  return MakeAccessorClosure(cls, selector, RawFunction::kGetFieldClosure);
+}
+
+
+DEFINE_NATIVE_ENTRY(Mirrors_makeSetter, 2) {
+  GET_NON_NULL_NATIVE_ARGUMENT(String, selector, arguments->NativeArgAt(0));
+  GET_NON_NULL_NATIVE_ARGUMENT(Type, scratch_type, arguments->NativeArgAt(1));
+  const Class& cls = Class::Handle(scratch_type.type_class());
+  return MakeAccessorClosure(cls, selector, RawFunction::kSetFieldClosure);
+}
+
+
 DEFINE_NATIVE_ENTRY(TypedefMirror_declaration, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(Type, type, arguments->NativeArgAt(0));
   const Class& cls = Class::Handle(type.type_class());