[profiler] Make certain Runtime Call Stats fields atomic.

src/counters.h

 // 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.
 
 #ifndef V8_COUNTERS_H_
 #define V8_COUNTERS_H_
 
 #include "include/v8.h"
 #include "src/allocation.h"
+#include "src/base/atomic-utils.h"
 #include "src/base/platform/elapsed-timer.h"
 #include "src/base/platform/time.h"
 #include "src/builtins/builtins.h"
 #include "src/globals.h"
 #include "src/isolate.h"
 #include "src/objects.h"
 #include "src/runtime/runtime.h"
 #include "src/tracing/trace-event.h"
 #include "src/tracing/traced-value.h"
 
@@ skipping 469 matching lines @@
 
   const char* name;
   int64_t count = 0;
   base::TimeDelta time;
 };
 
 // RuntimeCallTimer is used to keep track of the stack of currently active
 // timers used for properly measuring the own time of a RuntimeCallCounter.
 class RuntimeCallTimer {
  public:
-  RuntimeCallTimer() {}
   RuntimeCallCounter* counter() { return counter_; }
   base::ElapsedTimer timer() { return timer_; }
-  RuntimeCallTimer* parent() const { return parent_; }
+  RuntimeCallTimer* parent() const { return parent_.Value(); }
 
  private:
   friend class RuntimeCallStats;
 
   inline void Start(RuntimeCallCounter* counter, RuntimeCallTimer* parent) {
     counter_ = counter;
-    parent_ = parent;
+    parent_.SetValue(parent);
     timer_.Start();
   }
 
   inline RuntimeCallTimer* Stop() {
     base::TimeDelta delta = timer_.Elapsed();
     timer_.Stop();
     counter_->count++;
     counter_->time += delta;
-    if (parent_ != NULL) {
+    if (parent()) {
       // Adjust parent timer so that it does not include sub timer's time.
-      parent_->counter_->time -= delta;
+      parent()->counter_->time -= delta;
     }
-    return parent_;
+    return parent();
   }
 
   inline void Elapsed() {
     base::TimeDelta delta = timer_.Elapsed();
     counter_->time += delta;
-    if (parent_ != nullptr) {
-      parent_->counter_->time -= delta;
-      parent_->Elapsed();
+    if (parent()) {
+      parent()->counter_->time -= delta;
+      parent()->Elapsed();
     }
     timer_.Restart();
   }
 
   RuntimeCallCounter* counter_ = nullptr;
-  RuntimeCallTimer* parent_ = nullptr;
+  base::AtomicValue<RuntimeCallTimer*> parent_;
   base::ElapsedTimer timer_;
 };
 
 #define FOR_EACH_API_COUNTER(V)                            \
   V(ArrayBuffer_Cast)                                      \
   V(ArrayBuffer_Neuter)                                    \
   V(ArrayBuffer_New)                                       \
   V(Array_CloneElementAt)                                  \
   V(Array_New)                                             \
   V(BooleanObject_BooleanValue)                            \
@@ skipping 277 matching lines @@
 
   void Reset();
   void Print(std::ostream& os);
   V8_NOINLINE void Dump(v8::tracing::TracedValue* value);
 
   RuntimeCallStats() {
     Reset();
     in_use_ = false;
   }
 
-  RuntimeCallTimer* current_timer() { return current_timer_; }
+  RuntimeCallTimer* current_timer() { return current_timer_.Value(); }
   bool InUse() { return in_use_; }
 
  private:
   // Counter to track recursive time events.
-  RuntimeCallTimer* current_timer_ = NULL;
+  base::AtomicValue<RuntimeCallTimer*> current_timer_;
   // Used to track nested tracing scopes.
   bool in_use_;
 };
 
 #define TRACE_RUNTIME_CALL_STATS(isolate, counter_name) \
   do {                                                  \
     if (RuntimeCallStats::IsEnabled()) {                \
       RuntimeCallStats::CorrectCurrentCounterId(        \
           isolate->counters()->runtime_call_stats(),    \
           &RuntimeCallStats::counter_name);             \
@@ skipping 441 matching lines @@
   }
 
   Isolate* isolate_ = nullptr;
   RuntimeCallTimer timer_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COUNTERS_H_