Allow new CPU profiling subsystem to coexist nicely with the old one.

src/cpu-profiler.h

 // Copyright 2010 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 85 matching lines @@
  public:
   Address alias;
   Address start;
 
   INLINE(void UpdateCodeMap(CodeMap* code_map));
 };
 
 
 class TickSampleEventRecord BASE_EMBEDDED {
  public:
-  // In memory, the first machine word of a TickSampleEventRecord will be the
-  // first entry of TickSample, that is -- the VM state field.
-  // TickSample is put first, because 'order' can become equal to
-  // SamplingCircularQueue::kClear, while VM state can't, see
-  // the definition of 'enum StateTag'.
+  // The first machine word of a TickSampleEventRecord must not ever
+  // become equal to SamplingCircularQueue::kClear.  As both order and
+  // TickSample's first field are not reliable in this sense (order
+  // can overflow, TickSample can have all fields reset), we are
+  // forced to use an artificial filler field.
+  int filler;
+  unsigned order;
   TickSample sample;
-  unsigned order;
 
   static TickSampleEventRecord* cast(void* value) {
     return reinterpret_cast<TickSampleEventRecord*>(value);
   }
 
+  INLINE(static TickSampleEventRecord* init(void* value));
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(TickSampleEventRecord);
 };
 
 
 // This class implements both the profile events processor thread and
 // methods called by event producers: VM and stack sampler threads.
 class ProfilerEventsProcessor : public Thread {
  public:
   explicit ProfilerEventsProcessor(ProfileGenerator* generator);
@@ skipping 121 matching lines @@
   void StartCollectingProfile(String* title);
   void StartProcessorIfNotStarted();
   CpuProfile* StopCollectingProfile(const char* title);
   CpuProfile* StopCollectingProfile(String* title);
   void StopProcessorIfLastProfile();
 
   CpuProfilesCollection* profiles_;
   unsigned next_profile_uid_;
   ProfileGenerator* generator_;
   ProfilerEventsProcessor* processor_;
+  int saved_logging_nesting_;
 
   static CpuProfiler* singleton_;
 
 #else
   static INLINE(bool is_profiling()) { return false; }
 #endif  // ENABLE_CPP_PROFILES_PROCESSOR
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CpuProfiler);
 };
 
 } }  // namespace v8::internal
 
 
 #endif  // V8_CPU_PROFILER_H_