Rebuilding ghc changes interface hashes?

Matthias Kilian kili at
Wed Apr 6 00:14:18 CEST 2011

On Tue, Apr 05, 2011 at 08:51:52PM +0100, Simon Marlow wrote:
> >On Tue, Apr 05, 2011 at 09:59:23PM +0530, Joachim Breitner wrote:
> >>Also, the initial upload was built using ghc-6.12.1, while the upload
> >>now is build with ghc-7.0.2. Given that it is a two-stage compiler, I
> >>assume that the output should be identical, but it seems not to be the
> >>case.
> >
> >Changing the bootstrapping compiler changes the ABIs. The same can
> >happen if you interrupt and restart the build.
> In general changes can creep in randomly, there's no direct link between 
> changing the bootstrap compiler and getting different compilation 
> results (as far as I know), but there are some small elements of 
> randomness.

Oh, I confused those two problems again :-( But memories come back,
and IIRC the problem with the bootstrapping compiler is caused by
the "Booter version" (as printed by ghc --info) passed up to the
stage2 compiler. Wasn't the plan (about a year ago) to remove this?

If time permits, I'll send a patch in a few days, but I first have
to follow the switch to git, and I also want to update our (OpenBSDs)
ports to ghc-7.0.3 and hp-2011.2.


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