Bug 764021 - Add Startup Timeline probe for when entering main(). r=taras,r=bsmedberg

browser/app/nsBrowserApp.cpp

@@ -90,6 +90,7 @@ XRE_FreeAppDataType XRE_FreeAppData;
 XRE_SetupDllBlocklistType XRE_SetupDllBlocklist;
 #endif
 XRE_TelemetryAccumulateType XRE_TelemetryAccumulate;
+XRE_StartupTimelineRecordType XRE_StartupTimelineRecord;
 XRE_mainType XRE_main;
 
 static const nsDynamicFunctionLoad kXULFuncs[] = {
@@ -100,6 +101,7 @@ static const nsDynamicFunctionLoad kXULFuncs[] = {
     { "XRE_SetupDllBlocklist", (NSFuncPtr*) &XRE_SetupDllBlocklist },
 #endif
     { "XRE_TelemetryAccumulate", (NSFuncPtr*) &XRE_TelemetryAccumulate },
+    { "XRE_StartupTimelineRecord", (NSFuncPtr*) &XRE_StartupTimelineRecord },
     { "XRE_main", (NSFuncPtr*) &XRE_main },
     { nsnull, nsnull }
 };
@@ -189,8 +191,31 @@ bool IsPrefetchDisabledViaService()
 }
 #endif
 
+/* Local implementation of PR_Now, since the executable can't depend on NSPR */
+static PRTime _PR_Now()
+{
+#ifdef XP_WIN
+  MOZ_STATIC_ASSERT(sizeof(PRTime) == sizeof(FILETIME), "PRTime must have the same size as FILETIME");
+  FILETIME ft;
+  GetSystemTimeAsFileTime(&ft);
+  PRTime now;
+  CopyMemory(&now, &ft, sizeof(PRTime));
+#ifdef __GNUC__
+  return (now - 116444736000000000LL) / 10LL;
+#else
+  return (now - 116444736000000000i64) / 10i64;
+#endif
+
+#else
+  struct timeval tm;
+  gettimeofday(&tm, 0);
+  return (((PRTime)tm.tv_sec * 1000000LL) + (PRTime)tm.tv_usec);
+#endif
+}
+
 int main(int argc, char* argv[])
 {
+  PRTime start = _PR_Now();
   char exePath[MAXPATHLEN];
 
 #ifdef XP_MACOSX
@@ -247,6 +272,8 @@ int main(int argc, char* argv[])
     return 255;
   }
 
+  XRE_StartupTimelineRecord(mozilla::StartupTimeline::START, start);
+
 #ifdef XRE_HAS_DLL_BLOCKLIST
   XRE_SetupDllBlocklist();
 #endif

toolkit/components/startup/StartupTimeline.cpp

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "StartupTimeline.h"
+#include "nsXULAppAPI.h"
 
 namespace mozilla {
 
@@ -13,4 +14,15 @@ const char *StartupTimeline::sStartupTimelineDesc[StartupTimeline::MAX_EVENT_ID]
 #undef mozilla_StartupTimeline_Event
 };
 
+} /* namespace mozilla */
+
+/**
+ * The XRE_StartupTimeline_Record function is to be used by embedding applications
+ * that can't use mozilla::StartupTimeline::Record() directly.
+ */
+void
+XRE_StartupTimelineRecord(int aEvent, PRTime aWhen)
+{
+  mozilla::StartupTimeline::Record((mozilla::StartupTimeline::Event) aEvent, aWhen);
 }
+

toolkit/components/startup/StartupTimeline.h

@@ -4,6 +4,7 @@
 
 #ifdef mozilla_StartupTimeline_Event
 mozilla_StartupTimeline_Event(PROCESS_CREATION, "process")
+mozilla_StartupTimeline_Event(START, "start")
 mozilla_StartupTimeline_Event(MAIN, "main")
 // Record the beginning and end of startup crash detection to compare with crash stats to know whether
 // detection should be improved to start or end sooner.

xpcom/build/nsXULAppAPI.h

@@ -439,6 +439,9 @@ XRE_API(void,
 XRE_API(void,
         XRE_TelemetryAccumulate, (int aID, PRUint32 aSample))
 
+XRE_API(void,
+        XRE_StartupTimelineRecord, (int aEvent, PRTime aWhen))
+
 XRE_API(void,
         XRE_InitOmnijar, (nsIFile* greOmni,
                           nsIFile* appOmni))