Status of Mac 64 bit GHC

Gregory Wright gwright at
Mon Mar 7 19:06:54 GMT 2011

On 3/7/11 1:41 PM, Don Stewart wrote:
> Hey guys,
> Talking to Simon Marlow, he's suspicious that the 64 bit GHC for Mac
> isn't fully working yet. In particular, GHCi isn't working?
> Can someone confirm / deny GHC 7.0.2 64 bit Mac support is there? What
> is its state?
> If e.g. GHCi isn't workng, we better mark it as "experimental, try at
> your own risk" on the HP page
It mostly works.  I've not had a ghc-7-branch build fail for at least a 
of months now (unless I broke it myself while working).  For most purposes
ghci seems to work.  In rare cases it crashes, and it will be less reliable
than on other platforms.

The issue is this:  until quite recently, ghci's runtime linker didn't 
work at
all.  The biggest problems are fixed, buts since I was doing a lot of work
late in the release cycle, I can't guarantee that everything is OK.

I am trying to resolve all of the test failures on OS X 64 bit that affect
ghci exclusively.  There are perhaps 6 to 10 of these.  Some of them don't
happen all of the time, so they'll be hard to track down.  The first 
I looked at, time002 and time004, turned out to be unrelated to ghci, 
for some reason they only failed when run interactively.  This story
is available in ticket #4970.  My current effort is to resolve #5003.

It might be wise to label the release as "experimental" since it's the
first for OS X 64 bit.  But the best way to smoke out the remaining bugs
is to have more people try it.  Maybe call it a "preview release" and ask
people to file bug reports on the trac.  (In fact, if the ghci banner 
this information users could be considered appropriately warned.)


Gregory Wright
Antiope Associates LLC
18 Clay Street
Fair Haven, New Jersey 07733

+1 732 924-4549 [office]
+1 732 345-8378 [fax]
gwright at

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