Support profiling based on linux kernel performance events.

src/platform-freebsd.cc

 // Copyright 2006-2008 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 273 matching lines @@
     // There may be no filename in this line.  Skip to next.
     if (start_of_path == NULL) continue;
     buffer[bytes_read] = 0;
     LOG(SharedLibraryEvent(start_of_path, start, end));
   }
   close(fd);
 #endif
 }
 
 
+void OS::SignalCodeMovingGC() {
+}
+
+
 int OS::StackWalk(Vector<OS::StackFrame> frames) {
   int frames_size = frames.length();
   ScopedVector<void*> addresses(frames_size);
 
   int frames_count = backtrace(addresses.start(), frames_size);
 
   char** symbols = backtrace_symbols(addresses.start(), frames_count);
   if (symbols == NULL) {
     return kStackWalkError;
   }
@@ skipping 355 matching lines @@
   }
 
   // This sampler is no longer the active sampler.
   active_sampler_ = NULL;
   active_ = false;
 }
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal