Avoid a potential null dereference wrt the CPU profiler....

src/log.cc

 // Copyright 2009 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 289 matching lines @@
   TickSample sample;
   // Reset 'paused_' flag, otherwise semaphore may not be signalled.
   resume();
   Insert(&sample);
   Join();
 
   LOG(UncheckedStringEvent("profiler", "end"));
 }
 
 
 void Profiler::Run() {

[zarko, 2010/06/24 23:13:21]

Would it be helpful to ASSERT(Logger::profiler_ == this)?

   TickSample sample;
-  bool overflow = Logger::profiler_->Remove(&sample);
+  bool overflow = Remove(&sample);
   while (running_) {
     LOG(TickEvent(&sample, overflow));
-    overflow = Logger::profiler_->Remove(&sample);
+    overflow = Remove(&sample);
   }
 }
 
 
 //
 // Logger class implementation.
 //
 Ticker* Logger::ticker_ = NULL;
 Profiler* Logger::profiler_ = NULL;
 SlidingStateWindow* Logger::sliding_state_window_ = NULL;
@@ skipping 817 matching lines @@
     ASSERT(compression_helper_ != NULL);
     if (!compression_helper_->HandleMessage(&msg)) return;
   }
   msg.Append('\n');
   msg.WriteToLogFile();
 }
 
 
 int Logger::GetActiveProfilerModules() {
   int result = PROFILER_MODULE_NONE;
-  if (!profiler_->paused()) {
+  if (profiler_ != NULL && !profiler_->paused()) {
     result |= PROFILER_MODULE_CPU;
   }
   if (FLAG_log_gc) {
     result |= PROFILER_MODULE_HEAP_STATS | PROFILER_MODULE_JS_CONSTRUCTORS;
   }
   return result;
 }
 
 
 void Logger::PauseProfiler(int flags, int tag) {
   if (!Log::IsEnabled()) return;
-  if (flags & PROFILER_MODULE_CPU) {
+  if (profiler_ != NULL && (flags & PROFILER_MODULE_CPU)) {
     // It is OK to have negative nesting.
     if (--cpu_profiler_nesting_ == 0) {
       profiler_->pause();
       if (FLAG_prof_lazy) {
         if (!FLAG_sliding_state_window) ticker_->Stop();
         FLAG_log_code = false;
         // Must be the same message as Log::kDynamicBufferSeal.
         LOG(UncheckedStringEvent("profiler", "pause"));
       }
       --logging_nesting_;
@@ skipping 10 matching lines @@
     UncheckedIntEvent("close-tag", tag);
   }
 }
 
 
 void Logger::ResumeProfiler(int flags, int tag) {
   if (!Log::IsEnabled()) return;
   if (tag != 0) {
     UncheckedIntEvent("open-tag", tag);
   }
-  if (flags & PROFILER_MODULE_CPU) {
+  if (profiler_ != NULL && (flags & PROFILER_MODULE_CPU)) {
     if (cpu_profiler_nesting_++ == 0) {
       ++logging_nesting_;
       if (FLAG_prof_lazy) {
         profiler_->Engage();
         LOG(UncheckedStringEvent("profiler", "resume"));
         FLAG_log_code = true;
         LogCompiledFunctions();
         LogFunctionObjects();
         LogAccessorCallbacks();
         if (!FLAG_sliding_state_window) ticker_->Start();
@@ skipping 345 matching lines @@
   }
   // Otherwise, if the sliding state window computation has not been
   // started we do it now.
   if (sliding_state_window_ == NULL) {
     sliding_state_window_ = new SlidingStateWindow();
   }
 #endif
 }
 
 } }  // namespace v8::internal