[Haskell-cafe] OS X ghci problem

[Anthony Cowley]

On Jul 13, 2013, at 8:04 PM, Jason Dagit <dagitj at gmail.com> wrote:

> On Sat, Jul 13, 2013 at 4:39 PM, Mark Lentczner
> <mark.lentczner at gmail.com> wrote:
>> Bizarre - this just happened to me today, too. Anyone? Did you figure out a
>> work around? For the record, I'm trying to bring Euterpea up.
> 
> After some digging, experimenting, asking around, and head scratching
> my best guesses are:
> 
>  * GHCi's custom linker isn't doing the right thing (some versions of
> llvm/clang gave crashes like this and it was a linker bug for them,
> you can find reports on sites like StackOverflow).
>  * We need to feed .m files to clang instead of ghc/gcc
>  * GHCi needs to be built with Cocoa in mind (is it already?)
>  * Some rts component of objective-c is not properly initialized (ARC
> vs. -fobjc-gc vs. -fnext-step, etc)
> 
>> 
>> My system is OS X 10.8.4, and I'm running HP 2013.2, so 7.6.3. And
>> GLFW-0.5.1.0.
> 
> In terms of experimentation, you can hand desugar the objective-c code
> in the GLFW init and when I do that I get segfaults. Also, the address
> mentioned in the objective-c exception has a suspicious value, which
> would further implicate the linker. Add to that, it works for a
> compile program (which uses the system linker, IIRC).
> 
> Basically, I'm pretty sure it's GHCi's linker to blame here but I
> don't have a smoking gun.
> 
> Jason

I thought I'd had some success desugaring the Objective-C code, but I never went the whole way, so perhaps I just didn't get to the segfault. What I do for GLFW is use a dylib, then you don't rely on GHCi's static-ish linker. The only wrinkle is figuring out where you want the dylib. I think homebrew will put one in /usr/local/lib, which works out nicely, but they don't have GLFW 3 yet. Another option is to build the dylib yourself from the GLFW source bundled with the GLFW-b package, then tell cabal where to find it.

It's worth the trouble, as having a GHCi-based workflow for graphics work is wonderful. A fancy Setup.hs that works out installation paths could generate the dylib, and I thought such code existed in the past. Was some problem found with that approach?

Anthony