[MLton] Experimental 64Bit

[Matthew Fluet]

Ray wrote:
> I see the same floating point exception on a FC 5, dual AMD64.
> 
> I have been compiling along on the 64 bit branch without a problem I'd
> say within the last 3-4 weeks.  When I saw the announcement I did an
> update which appeared to be only a modest 10 files or so.  

Correct.  Up until the commits a few days preceding the announcement, 
the x86_64 branch was configured for 32-bit compatibility mode on 64-bit 
machines.

 > The make segfaulted on xmlShrink (if I recall).

That would be worth investigating.  I would suggest building a 32-bit 
mlton from the trunk, and then use that to build the x86_64 branch.

> The binary build from Experimental has the immediate floating point
> exception.
> 
> [raymond at corwin ~]$ which mlton
> /usr/local/bin/mlton
> [raymond at corwin ~]$ mlton
> Floating point exception
> [raymond at corwin ~]$ gdb /usr/local/lib/mlton/mlton-compile
> GNU gdb Red Hat Linux (6.3.0.0-1.134.fc5rh)
> 
> (gdb) run
> Starting program: /usr/local/lib/mlton/mlton-compile
> (no debugging symbols found)
> 
> Program received signal SIGFPE, Arithmetic exception.
> 0x0000003282608adb in do_lookup_x () from /lib64/ld-linux-x86-64.so.2
> (gdb) bt
> #0  0x0000003282608adb in do_lookup_x ()
> from /lib64/ld-linux-x86-64.so.2
> #1  0x0000003282608e6f in _dl_lookup_symbol_x ()
> from /lib64/ld-linux-x86-64.so.2
> #2  0x000000328260a546 in _dl_relocate_object ()
> from /lib64/ld-linux-x86-64.so.2
> #3  0x000000328260362a in dl_main () from /lib64/ld-linux-x86-64.so.2
> #4  0x0000003282612bdb in _dl_sysdep_start ()
> from /lib64/ld-linux-x86-64.so.2
> #5  0x0000003282601378 in _dl_start () from /lib64/ld-linux-x86-64.so.2
> #6  0x0000003282600a78 in _start () from /lib64/ld-linux-x86-64.so.2
> #7  0x0000000000000001 in ?? ()
> #8  0x00007fff100919be in ?? ()
> #9  0x0000000000000000 in ?? ()

That seems to be originating in the dynamic linking stage.  It would be 
helpful if you could run the mlton-compile.debug binary under gdb; that 
should have debugging symbols.