[turbofan] Introduce JSCallForwardVarargs operator.

src/runtime/runtime-compiler.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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/asmjs/asm-js.h"
 #include "src/compiler-dispatcher/optimizing-compile-dispatcher.h"
 #include "src/compiler.h"
@@ skipping 164 matching lines @@
   DCHECK_NULL(isolate->context());
 
   // TODO(turbofan): For Crankshaft we restore the context before objects are
   // being materialized, because it never de-materializes the context but it
   // requires a context to materialize arguments objects. This is specific to
   // Crankshaft and can be removed once only TurboFan goes through here.
   if (!optimized_code->is_turbofanned()) {
     JavaScriptFrameIterator top_it(isolate);
     JavaScriptFrame* top_frame = top_it.frame();
     isolate->set_context(Context::cast(top_frame->context()));
+  } else {
+    // TODO(turbofan): We currently need the native context to materialize
+    // the arguments object, but only to get to its map.
+    isolate->set_context(function->native_context());
   }
 
   // Make sure to materialize objects before causing any allocation.
   JavaScriptFrameIterator it(isolate);
   deoptimizer->MaterializeHeapObjects(&it);
   delete deoptimizer;
 
   // Ensure the context register is updated for materialized objects.
   if (optimized_code->is_turbofanned()) {
     JavaScriptFrameIterator top_it(isolate);
@@ skipping 275 matching lines @@
   DCHECK(is_valid_language_mode(args.smi_at(3)));
   LanguageMode language_mode = static_cast<LanguageMode>(args.smi_at(3));
   DCHECK(args[4]->IsSmi());
   Handle<SharedFunctionInfo> outer_info(args.at<JSFunction>(2)->shared(),
                                         isolate);
   return CompileGlobalEval(isolate, args.at<String>(1), outer_info,
                            language_mode, args.smi_at(4), args.smi_at(5));
 }
 }  // namespace internal
 }  // namespace v8