Segmentation faults with LLVM 3.4

[cdsousa]

While LLVM 3.4 support will probably be skiped (#4597 (comment)), I'm droping here some backtraces I obtained when I was inadvertently using Julia with my system LLVM v3.4.

Short story: I got this segfaults when doing Pkg.update():
https://gist.github.com/cdsousa/9cfa5307ae221e72f2e2#file-julia_nok_log
https://gist.github.com/cdsousa/a18439acba05a64d8476

Long story: https://groups.google.com/forum/#!topic/julia-users/5zjoL6nMHyE

Isaiah asked me to open this issue. I'm available for more tests if it's worth.

[Keno]

Unfortunately I suspect these are due to memory corruption. I've been trying to track these down, but no luck so far.

[JeffBezanson]

Thanks; it's always good to capture this stuff.

[cdsousa]

I'm not sure if this can be useful, but let me add that when I was unawarely using LLVM v3.4, I'd tackled a segmentation fault in IJulia for which I did a PR: JuliaLang/IJulia.jl#142

It seems that the segfault was due to a cfunction object, which was being passed to a pthread_create, going out of scope too soon.

I can confirm that segmentation fault occurred solely due to LLVM v3.4, since after the change back to v3.3 IJulia works without the patch.

[Keno]

Thanks for that info, that might actually be extremely helpful.

[Keno]

Fixed by 5c1b5ad