Improve the shutdownHaskellAndSignal and add fast exit

This is the RTS part of a patch to base's topHandler to handle exiting
by a signal.

The intended behaviour is that on Unix, throwing ExitFailure (-sig)
results in the process terminating with that signal. Previously
shutdownHaskellAndSignal was only used for exiting with SIGINT due to
the UserInterrupt exception.

Improve shutdownHaskellAndSignal to do the signal part more carefully.
In particular, it (should) now reliably terminates the process one way
or another. Previusly if the signal was blocked, ignored or handled then
shutdownHaskellAndSignal would actually return!

Also, the topHandler code has two paths a careful shutdown and a "fast
exit" where it does not give finalisers a chance to run. We want to
support that mode also when we want to exit by signal. So rather than
the base code directly calling stg_exit as it did before, we have a
fastExit bool paramater for both shutdownHaskellAnd{Exit,Signal}.

1 files changed, 4 insertions, 6 deletions

diff --git a/includes/RtsAPI.h b/includes/RtsAPI.h
index 29c28d8fcc..daae30b821 100644
--- a/includes/RtsAPI.h
+++ b/includes/RtsAPI.h
@@ -94,14 +94,12 @@ extern void hs_init_with_rtsopts (int *argc, char **argv[]);
 extern void hs_init_ghc (int *argc, char **argv[],   // program arguments
                          RtsConfig rts_config);      // RTS configuration
 
-extern void shutdownHaskellAndExit ( int exitCode )
-#if __GNUC__ >= 3
-    __attribute__((__noreturn__))
-#endif
-    ;
+extern void shutdownHaskellAndExit (int exitCode, int fastExit)
+    GNUC3_ATTRIBUTE(__noreturn__);
 
 #ifndef mingw32_HOST_OS
-extern void shutdownHaskellAndSignal (int sig);
+extern void shutdownHaskellAndSignal (int sig, int fastExit)
+     GNUC3_ATTRIBUTE(__noreturn__);
 #endif
 
 extern void getProgArgv            ( int *argc, char **argv[] );