Implement Function.prototype.toMethod.

src/objects.cc

 // Copyright 2013 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/v8.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
 #include "src/api.h"
 #include "src/arguments.h"
@@ skipping 9281 matching lines @@
     PrintF("  ** Queueing ");
     PrintName();
     PrintF(" for concurrent recompilation.\n");
   }
   set_code_no_write_barrier(
       GetIsolate()->builtins()->builtin(Builtins::kInOptimizationQueue));
   // No write barrier required, since the builtin is part of the root set.
 }
 
 
+Handle<JSFunction> JSFunction::CloneClosure(Handle<JSFunction> function) {
+  Isolate* isolate = function->GetIsolate();
+  Handle<Map> map(function->map());
+  Handle<SharedFunctionInfo> shared(function->shared());
+  Handle<Context> context(function->context());
+  Handle<JSFunction> clone =
+      isolate->factory()->NewFunctionFromSharedFunctionInfo(shared, context);
+
+  if (shared->bound()) {
+    clone->set_function_bindings(function->function_bindings());
+  }
+
+  // In typical case, __proto__ of ``function`` is the default Function
+  // prototype, which means that SetPrototype below is a no-op.

[Toon Verwaest, 2014/08/21 11:32:28]

Now this comment is a bit off

+  // In rare cases when that is not true, we mutate the clone's __proto__.
+  Handle<Object> original_prototype(map->prototype(), isolate);
+  if (*original_prototype != clone->map()->prototype()) {
+    JSObject::SetPrototype(clone, original_prototype, false).Assert();
+  }
+
+  return clone;
+}
+
+
 void SharedFunctionInfo::AddToOptimizedCodeMap(
     Handle<SharedFunctionInfo> shared,
     Handle<Context> native_context,
     Handle<Code> code,
     Handle<FixedArray> literals,
     BailoutId osr_ast_id) {
   Isolate* isolate = shared->GetIsolate();
   DCHECK(code->kind() == Code::OPTIMIZED_FUNCTION);
   DCHECK(native_context->IsNativeContext());
   STATIC_ASSERT(kEntryLength == 4);
@@ skipping 7250 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal