GitLab

Random cleanup: rename the TSO->whatNext field to what_next, to be a
bit more consistent.

comment spelling typo wurble

Merged GUM-4-04 branch into the main trunk. In particular merged GUM and
SMP code. Most of the GranSim code in GUM-4-04 still has to be carried over.

A slew of SMP-related changes.

 - New locking scheme for thunks: we now check whether the thunk
   being entered is in our private allocation area, and if so
   we don't lock it.  Well, that's the upshot.  In practice it's
   a lot more fiddly than that.

 - I/O blocking is handled a bit more sanely now (but still not
   properly, methinks)

 - deadlock detection is back

 - remove old pre-SMP scheduler code

 - revamp the timing code.  We actually get reasonable-looking
   timing info for SMP programs now.

 - fix a bug in the garbage collector to do with IND_OLDGENs appearing
   on the mutable list of the old generation.

 - move BDescr() function from rts/BlockAlloc.h to includes/Block.h.

 - move struct generation and struct step into includes/StgStorage.h (sigh)

 - add UPD_IND_NOLOCK for updating with an indirection where locking
   the black hole is not required.

Support for thread{WaitRead,WaitWrite,Delay}.  These should behave
identically to the 3.02 implementations.

We now have the virtual timer on during all program runs, which ticks
at 50Hz by default.  This is used to implement threadDelay, so you
won't get any better granularity than the tick frequency
unfortunately.  It remains to be seen whether using the virtual timer
will have a measurable impact on performance for non-threadDelaying
programs.

All operations in the I/O subsystem should now be non-blocking with
respect to other running Haskell threads.  It remains to be seen
whether this will have a measurable performance impact on
non-concurrent programs (probably not).

stg_gc_noregs should leave the return address on the stack (it's a
case alternative).

Support for "unregisterised" builds.  An unregisterised build doesn't
use the assembly mangler, doesn't do tail jumping (uses the
mini-interpreter), and doesn't use global register variables.

Plenty of cleanups and bugfixes in the process.

Add way 'u' to GhcLibWays to get unregisterised libs & RTS.

[ note: not *quite* working fully yet... there's still a bug or two
  lurking ]

Add missing semicolon

- Stack overflow now generates an (AsyncException StackOverflow)
  exception, which can be caught as normal.

- Add a stack overflow handler to the top-level mainIO handler, with
  the standard behaviour (i.e. call the stack overflow hook and then
  exit).

- Add a test for stack overflow catching.

- Fix a couple of bugs in async exception support.

Improvements to the threading model.

   - asynchronous exceptions supported.

	- killThread# can now raise an exception in the specified
	  thread.  It's new type is

		killThread# :: ThreadId# -> Exception -> IO ()

	  High-level versions:

		killThread :: ThreadId -> IO ()
		raiseInThread :: ThreadId -> Exception -> IO ()

	  (killThread raises a 'ThreadKilled' exception in the
	   specified thread).

	  If the thread has no exception handler, it is killed
	  as before.  Otherwise, the exception is passed to
	  the innermost CATCH_FRAME and the thread is woken up
	  if it was blocked.  The current computation is
	  suspended, instead of being replaced by the exception
	  (as is the case with throw).

	  Sending an exception to the current thread works too.

   - new primitive: myThreadId# :: IO ThreadId# and corresponding
     high-level version myThreadId :: IO ThreadId.

   - new primitive: yield# :: IO (), and yield :: IO ().

   - the TSO now contains a pointer to the resource currently blocked
     on (MVAR or BLACKHOLE_BQ).

  - Add a giant comment to TSO.h about what the various link fields
    are supposed to do, and invariants etc.

Copyright police.

Move 4.01 onto the main trunk.