Controlling -fno-unit-at-a-time

Simon Marlow simonmarhaskell at
Thu Oct 5 05:55:44 EDT 2006

Ian Lynagh wrote:
> On Tue, Oct 03, 2006 at 04:59:58PM -0400, Ravi Nanavati wrote:
>>If I understand the way things work, GHC decides whether or not to emit 
>>the -fno-unit-at-a-time flag in -fvia-C compilation based on whether or 
>>not the gcc used when compiling GHC supported the flag or not. I'm 
>>running into trouble using precompiled GHC snapshots (that were compiled 
>>on machines whose gcc supports -fno-unit-at-a-time) on a machine whose 
>>gcc doesn't support it (a gcc 3.2 version, I believe).
>>Is there any way force GHC to not emit the flag (short of recompiling 
>>from source)?
> Not really. You could use a small gcc wrapper to remove it (you can
> point to it with -pgmc if you don't want to contaminate your path with
> it).
> You could probably also change the 'f' to a 'D' with a hex editor, but
> I'm not sure why anyone would prefer that solution.

It would be nice if these kind of configuration settings were in some file 
rather than being baked into GHC.  I think it might be possible to pass in these 
flags via the package configuration for the rts package, for example.


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