DO NOT MERGE! Temporarily patch in perf support to llvm.

[stuartarchibald]

As title.

[stuartarchibald]

Ping @seibert. Approximate instructions:

1. conda build llvmdev
2. conda build llvmlite
3. conda create -n perf_tool -c numba <then either -c for a channel or --use-local for where the special builds are > llvmlite=0.28*_perf_tool numpy gcc_linux-64 gxx_linux-64 colorama pyyaml ipython python=3 numba
4. source activate perf_tool
5. NUMBA_ENABLE_PROFILING=1 perf record -o perf.data -g -k 1 python some_example_or_other.py
6. perf inject --jit -i perf.data -o perf.jit.data
7. Profit:
   • perf report -i perf.jit.data should work
   • perf annotate -i perf.jit.data should also work

Watch out for the dump directory ~/.debug/jit getting v. full, synthesized DSOs/maps are left there. There's a non-public environment variable referenced in the LLVM src, JITDUMPDIR, which can be set to move the aforementioned dump dir to somewhere else.

[stuartarchibald]

Builds are on the Numba channel: -c numba/label/perf_tool llvmlite=0.28*perf_tool, direct drop in for llvmlite built from 0.280dev0 mainline. This:

conda create -n perf_tool  -c numba/label/perf_tool llvmlite=0.28*perf_tool numba

bypasses 1., 2. and 3. above.

[esc]

@stuartarchibald is this PR still needed? If not, do we want to include the instructions for using perf in the developer documentation for llvmlite?

[gmarkall]

@stuartarchibald Can we close this now?

[stuartarchibald]

@stuartarchibald Can we close this now?

Yes!