[turbofan] Support for typed lowering of "prototype" load from functions.

test/unittests/compiler/js-typed-lowering-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 934 matching lines @@
         graph()->NewNode(javascript()->LoadNamed(language_mode, name, feedback),
                          receiver, vector, context, EmptyFrameState(),
                          EmptyFrameState(), effect, control));
     ASSERT_TRUE(r.Changed());
     EXPECT_THAT(r.replacement(), IsLoadField(AccessBuilder::ForStringLength(),
                                              receiver, effect, control));
   }
 }
 
 
+TEST_F(JSTypedLoweringTest, JSLoadNamedFunctionPrototype) {
+  VectorSlotPair feedback;
+  Handle<Name> name = factory()->prototype_string();
+  Handle<JSFunction> function = isolate()->object_function();
+  Handle<JSObject> function_prototype(JSObject::cast(function->prototype()));
+  Node* const receiver = Parameter(Type::Constant(function, zone()), 0);
+  Node* const vector = Parameter(Type::Internal(), 1);
+  Node* const context = Parameter(Type::Internal(), 2);
+  Node* const effect = graph()->start();
+  Node* const control = graph()->start();
+  TRACED_FOREACH(LanguageMode, language_mode, kLanguageModes) {
+    Reduction const r = Reduce(
+        graph()->NewNode(javascript()->LoadNamed(language_mode, name, feedback),
+                         receiver, vector, context, EmptyFrameState(),
+                         EmptyFrameState(), effect, control));
+    ASSERT_TRUE(r.Changed());
+    EXPECT_THAT(r.replacement(), IsHeapConstant(function_prototype));
+  }
+}
+
+
 // -----------------------------------------------------------------------------
 // JSAdd
 
 
 TEST_F(JSTypedLoweringTest, JSAddWithString) {
   TRACED_FOREACH(LanguageMode, language_mode, kLanguageModes) {
     Node* lhs = Parameter(Type::String(), 0);
     Node* rhs = Parameter(Type::String(), 1);
     Node* context = Parameter(Type::Any(), 2);
     Node* frame_state0 = EmptyFrameState();
@@ skipping 297 matching lines @@
   Node* dummy = graph()->NewNode(javascript()->ToObject(), instanceOf, context,
                                  frame_state, effect, control);
   Reduction r = Reduce(instanceOf);
   ASSERT_FALSE(r.Changed());
   ASSERT_EQ(instanceOf, dummy->InputAt(0));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8