[turbofan] Ship generators if --turbo-from-bytecode set.

src/ast/ast-numbering.cc

 // Copyright 2012 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/ast/ast-numbering.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 
 namespace v8 {
@@ skipping 574 matching lines @@
   if (scope->calls_eval()) DisableCrankshaft(kFunctionCallsEval);
   if (scope->arguments() != NULL && !scope->arguments()->IsStackAllocated()) {
     DisableCrankshaft(kContextAllocatedArguments);
   }
 
   if (scope->rest_parameter() != nullptr) {
     DisableCrankshaft(kRestParameter);
   }
 
   if (IsGeneratorFunction(node->kind()) || IsAsyncFunction(node->kind())) {
-    // TODO(neis): We may want to allow Turbofan optimization here if
-    // --turbo-from-bytecode is set and we know that Ignition is used.
-    // Unfortunately we can't express that here.
-    DisableOptimization(kGenerator);
+    // Generators can be optimized if --turbo-from-bytecode is set.
+    if (FLAG_turbo_from_bytecode) {
+      DisableCrankshaft(kGenerator);
+    } else {
+      DisableOptimization(kGenerator);
+    }
   }
 
   VisitDeclarations(scope->declarations());
   VisitStatements(node->body());
 
   node->set_ast_properties(&properties_);
   node->set_dont_optimize_reason(dont_optimize_reason());
   node->set_yield_count(yield_count_);
   return !HasStackOverflow();
 }
 
 
 bool AstNumbering::Renumber(Isolate* isolate, Zone* zone,
                             FunctionLiteral* function) {
   AstNumberingVisitor visitor(isolate, zone);
   return visitor.Renumber(function);
 }
 }  // namespace internal
 }  // namespace v8