Adding NUMBA_ENABLE_PROFILING envvar, enabling jit event

[anton-malakhov]

Default value depends on whether profiling was detected
It also serves as a default value for NUMBA_DEBUGINFO

@sklam @seibert

[anton-malakhov]

On Azure, the build error is not related to this PR: 2018-09-13T19:36:47.6095703Z ./miniconda.sh: 373: ./miniconda.sh: /home/vsts/miniconda3/pkgs/python-3.7.0-hc3d631a_0/bin/python: not found

[seibert]

Yeah, this is a random failure that just started happening due to something strange (and apparently random) in the environment setup. It's almost like some of the build machines on Azure are behaving differently than others.

[anton-malakhov]

Ok, I'll try to restart testing by force-pushing this commit

[seibert]

Don't worry too much about it for now. We're treating the Azure results as "informative" while we evaluate how stable the service is.

[anton-malakhov]

@seibert could you please review the envvar name and changes to the defaults in this PR? I could sketch a doc section as well, if it works for you this way

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@289254b). Click here to learn what that means.
The diff coverage is 0%.

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[seibert]

This looks fine to me, but what code is calling lib_from_sym in helperlib?

[anton-malakhov]

Oops.. looks like it is a branch collision - I forgot I have this PR open and created this function for solving certain issues with multiple openmp copies. I'll roll it back

[stuartarchibald]

Thanks for the patch. On inspection this looks good. Will be interesting to see if perf can also be enabled in LLVM 7.

[sklam]

adding reference to numba/llvmlite#394

[stuartarchibald]

Testing this PR needs merge of #3424, then to do a merge build with master so as to pick up llvmlite 0.26 (where the linked changes are proposed).

[stuartarchibald]

Smoke test build passed, only failures were unrelated. Merging!

[anton-malakhov]

Thanks!

[stuartarchibald]

No problem. Thanks for the contribution!