eventlog: Repost initialisation events when eventlog restarts

If startEventlog is called after the program has already started running
then quite a few useful events are missing from the eventlog because
they are only posted when the program starts. This patch adds a
mechanism to declare that an event should be reposted everytime the
startEventlog function is called.

Now in EventLog.c there is a global list of functions called
`eventlog_header_funcs` which stores a list of functions which should be
called everytime the eventlog starts.

When calling `postInitEvent`, the event will not only be immediately
posted to the eventlog but also added to the global list.

When startEventLog is called, the list is traversed and the events
reposted.

1 files changed, 3 insertions, 3 deletions

diff --git a/rts/RtsStartup.c b/rts/RtsStartup.c
index 5cad851b80..371c96d08c 100644
--- a/rts/RtsStartup.c
+++ b/rts/RtsStartup.c
@@ -300,8 +300,8 @@ hs_init_ghc(int *argc, char **argv[], RtsConfig rts_config)
     initScheduler();
 
     /* Trace some basic information about the process */
-    traceWallClockTime();
-    traceOSProcessInfo();
+    traceInitEvent(traceWallClockTime);
+    traceInitEvent(traceOSProcessInfo);
     flushTrace();
 
     /* initialize the storage manager */
@@ -370,7 +370,7 @@ hs_init_ghc(int *argc, char **argv[], RtsConfig rts_config)
 #if defined(PROFILING)
     initProfiling();
 #endif
-    dumpIPEToEventLog();
+    traceInitEvent(dumpIPEToEventLog);
     initHeapProfiling();
 
     /* start the virtual timer 'subsystem'. */