[MLton] cygwoes

Tom Murphy tom7@cs.cmu.edu
Thu, 29 Sep 2005 22:15:39 -0400 (EDT)


Hmm, I think we are thinking about different problems. My problem is that
although old mlton-compiled programs appear to work fine with the new
cygwin, I am unable to compile any new programs (even the empty program)
because mlton fails to invoke gcc. Do you think that these problems with
the runtime are the cause, or is that another cygwin show-stopper that I
don't know about? (Unfortunately, my optimism about fixing a runtime bug
is somewhat lower than some kind of path/environment problem..)

 - Tom

>
> > Any word on the cygwin problem?
>
> I made a little progress.  The way I usually debug stuff on Cygwin is
> by cross compiling the regressions.  I don't see the signal B error
> that you do.  Rather, I see
>
>   VirtualFree release failed
>
> Hopefully they are related, although who knows.
>
> MLton has two different ways of grabbing memory from the OS on Cygwin:
> Virtual{Alloc,Free} or (the Cygwin-emulated) mmap.  In the past,
> Virtual{Alloc,Free} has been more stable and gave access to more
> memory, so we made it the default.  Perhaps that is no longer true.
> We have a runtime flag, use-mmap, which forces the runtime to use
> mmap.  I am able to get all of our regressions to pass on Cygwin,
> provided that I run them with @MLton use-mmap --.
>
> As a stopgap, you could cross-compile your program with
>
>   -runtime use-mmap
>
> to force the executable to use mmap.  You might even try a full
> bootstrap with use-mmap, possibly even tweaking GC_init in gc.c to set
>
>   MLton_Platform_CygwinUseMmap = TRUE;
>
> You could also try experiments with Virtual{Alloc,Free} by compiling
> the runtime with DEBUG_MEM = TRUE in platform.h.  There are a couple
> of other DEBUG_* flags in gc.c that might shed some light:
> DEBUG_RESIZING comes to mind.
>
> > I'm willing to try to fix this if someone can give me a tip on what it
> > might be. Or is the release right around the corner?
>
> The release has been right around the corner for over a month, the
> delay being due only to the Cygwin problem.  It would be great if you
> could fix it.  MLton might even be able to release!
>
>


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