Bug 1572337: ensure MainThread is registered with the profiler properly r=gerald

Differential Revision: https://phabricator.services.mozilla.com/D41619

--HG--
extra : moz-landing-system : lando

tools/profiler/core/RegisteredThread.cpp

@@ -6,7 +6,7 @@
 
 #include "RegisteredThread.h"
 
-RegisteredThread::RegisteredThread(ThreadInfo* aInfo, nsIEventTarget* aThread,
+RegisteredThread::RegisteredThread(ThreadInfo* aInfo, nsIThread* aThread,
                                    void* aStackTop)
     : mRacyRegisteredThread(aInfo->ThreadId()),
       mPlatformData(AllocPlatformData(aInfo->ThreadId())),
@@ -18,6 +18,9 @@ RegisteredThread::RegisteredThread(ThreadInfo* aInfo, nsIEventTarget* aThread,
       mJSFlags(0) {
   MOZ_COUNT_CTOR(RegisteredThread);
 
+  // NOTE: aThread can be null for the first thread, before the ThreadManager
+  // is initialized.
+
   // We don't have to guess on mac
 #if defined(GP_OS_darwin)
   pthread_t self = pthread_self();

tools/profiler/core/RegisteredThread.h

@@ -140,7 +140,7 @@ class RacyRegisteredThread final {
 // protected by the profiler state lock.
 class RegisteredThread final {
  public:
-  RegisteredThread(ThreadInfo* aInfo, nsIEventTarget* aThread, void* aStackTop);
+  RegisteredThread(ThreadInfo* aInfo, nsIThread* aThread, void* aStackTop);
   ~RegisteredThread();
 
   class RacyRegisteredThread& RacyRegisteredThread() {
@@ -179,6 +179,7 @@ class RegisteredThread final {
 
   const RefPtr<ThreadInfo> Info() const { return mThreadInfo; }
   const nsCOMPtr<nsIEventTarget> GetEventTarget() const { return mThread; }
+  void ResetMainThread(nsIThread* aThread) { mThread = aThread; }
 
   // Request that this thread start JS sampling. JS sampling won't actually
   // start until a subsequent PollJSSampling() call occurs *and* mContext has
@@ -254,7 +255,7 @@ class RegisteredThread final {
   const void* mStackTop;
 
   const RefPtr<ThreadInfo> mThreadInfo;
-  const nsCOMPtr<nsIEventTarget> mThread;
+  nsCOMPtr<nsIThread> mThread;
 
   // If this is a JS thread, this is its JSContext, which is required for any
   // JS sampling.

tools/profiler/core/platform.cpp

@@ -3222,6 +3222,17 @@ static Vector<const char*> SplitAtCommas(const char* aString,
   return array;
 }
 
+void profiler_init_threadmanager() {
+  LOG("profiler_init_threadmanager");
+
+  PSAutoLock lock(gPSMutex);
+  RegisteredThread* registeredThread =
+      TLSRegisteredThread::RegisteredThread(lock);
+  if (!registeredThread->GetEventTarget()) {
+    registeredThread->ResetMainThread(NS_GetCurrentThreadNoCreate());
+  }
+}
+
 void profiler_init(void* aStackTop) {
   LOG("profiler_init");
 

tools/profiler/public/GeckoProfiler.h

@@ -30,6 +30,7 @@
 // avoid the need for many #ifdefs.
 
 #  define AUTO_PROFILER_INIT
+#  define AUTO_PROFILER_INIT2
 
 #  define PROFILER_REGISTER_THREAD(name)
 #  define PROFILER_UNREGISTER_THREAD()
@@ -300,8 +301,12 @@ static constexpr mozilla::PowerOfTwo32 PROFILER_DEFAULT_STARTUP_ENTRIES =
 // (except profiler_start(), which will call profiler_init() if it hasn't
 // already run).
 void profiler_init(void* stackTop);
+void profiler_init_threadmanager();
 
+// Call this as early as possible
 #  define AUTO_PROFILER_INIT mozilla::AutoProfilerInit PROFILER_RAII
+// Call this after the nsThreadManager is Init()ed
+#  define AUTO_PROFILER_INIT2 mozilla::AutoProfilerInit2 PROFILER_RAII
 
 // Clean up the profiler module, stopping it if required. This function may
 // also save a shutdown profile if requested. No profiler calls should happen
@@ -960,6 +965,17 @@ class MOZ_RAII AutoProfilerInit {
   MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 };
 
+class MOZ_RAII AutoProfilerInit2 {
+ public:
+  explicit AutoProfilerInit2(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM) {
+    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+    profiler_init_threadmanager();
+  }
+
+ private:
+  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
+};
+
 // Convenience class to register and unregister a thread with the profiler.
 // Needs to be the first object on the stack of the thread.
 class MOZ_RAII AutoProfilerRegisterThread final {

tools/profiler/public/ProfilerCounts.h

@@ -92,11 +92,14 @@ class BaseProfilerCount {
 #  endif
     // Can't call profiler_* here since this may be non-xul-library
   }
-#  ifdef DEBUG
-  ~BaseProfilerCount() { mCanary = 0; }
-#  endif
 
-  void Sample(int64_t& aCounter, uint64_t& aNumber) {
+  virtual ~BaseProfilerCount() {
+#  ifdef DEBUG
+    mCanary = 0;
+#  endif
+  }
+
+  virtual void Sample(int64_t& aCounter, uint64_t& aNumber) {
     MOZ_ASSERT(mCanary == COUNTER_CANARY);
 
     aCounter = *mCounter;

xpcom/build/XPCOMInit.cpp

@@ -324,6 +324,7 @@ NS_InitXPCOM(nsIServiceManager** aResult, nsIFile* aBinDirectory,
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
+  AUTO_PROFILER_INIT2;
 
   // Init the SystemGroup for dispatching main thread runnables.
   SystemGroup::InitStatic();