[compiler] Put shared function marking behind a flag

src/objects.cc

 // Copyright 2015 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <memory>
 #include <sstream>
@@ skipping 12194 matching lines @@
   DCHECK(!IsOptimized());
   DCHECK(shared()->allows_lazy_compilation() ||
          !shared()->optimization_disabled());
   set_code_no_write_barrier(
       isolate->builtins()->builtin(Builtins::kCompileOptimized));
   // No write barrier required, since the builtin is part of the root set.
 }
 
 
 void JSFunction::AttemptConcurrentOptimization() {
-  // Mark the shared function for optimization regardless of whether the
-  // optimization is concurrent or not.
-  shared()->set_was_marked_for_optimization(true);
+  if (FLAG_optimize_shared_functions) {
+    // Mark the shared function for optimization regardless of whether the
+    // optimization is concurrent or not.
+    shared()->set_was_marked_for_optimization(true);
+  }
 
   Isolate* isolate = GetIsolate();
   if (!isolate->concurrent_recompilation_enabled() ||
       isolate->bootstrapper()->IsActive()) {
     MarkForOptimization();
     return;
   }
   DCHECK(!IsInOptimizationQueue());
   DCHECK(!IsOptimized());
   DCHECK(shared()->allows_lazy_compilation() ||
@@ skipping 7992 matching lines @@
         ns, Accessors::ModuleNamespaceEntryInfo(isolate, name, attr))
         .Check();
   }
   JSObject::PreventExtensions(ns, THROW_ON_ERROR).ToChecked();
 
   return ns;
 }
 
 }  // namespace internal
 }  // namespace v8