[es7] Add --harmony-explicit-tailcalls flag.

src/bootstrapper.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/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/code-stubs.h"
 #include "src/extensions/externalize-string-extension.h"
@@ skipping 2387 matching lines @@
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_object_observe)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_unicode_regexps)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_do_expressions)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_iterator_close)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_regexp_exec)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_regexp_lookbehind)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_regexp_property)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_function_name)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_function_sent)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(promise_extra)
+EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_explicit_tailcalls)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_tailcalls)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_instanceof)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_restrictive_declarations)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_exponentiation_operator)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_string_padding)
 
 void InstallPublicSymbol(Factory* factory, Handle<Context> native_context,
                          const char* name, Handle<Symbol> value) {
   Handle<JSGlobalObject> global(
       JSGlobalObject::cast(native_context->global_object()));
@@ skipping 523 matching lines @@
   }
 
   return true;
 }
 
 
 bool Genesis::InstallExperimentalNatives() {
   static const char* harmony_iterator_close_natives[] = {nullptr};
   static const char* harmony_species_natives[] = {"native harmony-species.js",
                                                   nullptr};
+  static const char* harmony_explicit_tailcalls_natives[] = {nullptr};
   static const char* harmony_tailcalls_natives[] = {nullptr};
   static const char* harmony_unicode_regexps_natives[] = {
       "native harmony-unicode-regexps.js", nullptr};
   static const char* harmony_object_observe_natives[] = {
       "native harmony-object-observe.js", nullptr};
   static const char* harmony_sharedarraybuffer_natives[] = {
       "native harmony-sharedarraybuffer.js", "native harmony-atomics.js", NULL};
   static const char* harmony_simd_natives[] = {"native harmony-simd.js",
                                                nullptr};
   static const char* harmony_do_expressions_natives[] = {nullptr};
@@ skipping 681 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8