[counters] Put all counter work behind flags

src/builtins.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/builtins.h"
 
 #include "src/api.h"
 #include "src/api-natives.h"
 #include "src/arguments.h"
 #include "src/base/once.h"
@@ skipping 124 matching lines @@
 //   }
 //
 // In the body of the builtin function the arguments can be accessed
 // through the BuiltinArguments object args.
 
 #define BUILTIN(name)                                                          \
   MUST_USE_RESULT static Object* Builtin_Impl_##name(name##ArgumentsType args, \
                                                      Isolate* isolate);        \
   MUST_USE_RESULT static Object* Builtin_##name(                               \
       int args_length, Object** args_object, Isolate* isolate) {               \
+    Object* value;                                                             \
     isolate->counters()->runtime_calls()->Increment();                         \
-    RuntimeCallStats* stats = isolate->counters()->runtime_call_stats();       \
-    RuntimeCallTimerScope timer(isolate, &stats->Builtin_##name);              \
     TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.runtime"),                      \
                  "V8.Builtin_" #name);                                         \
     name##ArgumentsType args(args_length, args_object);                        \
-    Object* value = Builtin_Impl_##name(args, isolate);                        \
+    if (FLAG_runtime_call_stats) {                                             \
+      RuntimeCallStats* stats = isolate->counters()->runtime_call_stats();     \
+      RuntimeCallTimerScope timer(isolate, &stats->Builtin_##name);            \
+      value = Builtin_Impl_##name(args, isolate);                              \
+    } else {                                                                   \
+      value = Builtin_Impl_##name(args, isolate);                              \
+    }                                                                          \
     return value;                                                              \
   }                                                                            \
                                                                                \
   MUST_USE_RESULT static Object* Builtin_Impl_##name(name##ArgumentsType args, \
                                                      Isolate* isolate)
 
 // ----------------------------------------------------------------------------
 
 
 #define CHECK_RECEIVER(Type, name, method)                                  \
@@ skipping 4376 matching lines @@
 BUILTIN_LIST_C(DEFINE_BUILTIN_ACCESSOR_C)
 BUILTIN_LIST_A(DEFINE_BUILTIN_ACCESSOR_A)
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 
 
 }  // namespace internal
 }  // namespace v8