ll_prof: Reduce profiling hooks overhead from >400% to 25%.

src/isolate.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 800 matching lines @@
   // Deserializing may put strange things in the root array's copy of the
   // stack guard.
   heap_.SetStackLimits();
 
   deoptimizer_data_ = new DeoptimizerData;
   runtime_profiler_ = new RuntimeProfiler(this);
   runtime_profiler_->Setup();
 
   // If we are deserializing, log non-function code objects and compiled
   // functions found in the snapshot.
-  if (des != NULL && FLAG_log_code) {
+  if (des != NULL && (FLAG_log_code || FLAG_ll_prof)) {
     HandleScope scope;
     LOG(this, LogCodeObjects());
     LOG(this, LogCompiledFunctions());
   }
 
   state_ = INITIALIZED;
   return true;
 }
 
 
@@ skipping 75 matching lines @@
 
 #ifdef DEBUG
 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                       \
 const intptr_t Isolate::name##_debug_offset_ = OFFSET_OF(Isolate, name##_);
 ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
 ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
 #undef ISOLATE_FIELD_OFFSET
 #endif
 
 } }  // namespace v8::internal