[XRay] Add Google Benchmark library + initial XRay benchmarks
Summary:
Google benchmark library 1.1.0.
Add initial XRay benchmarks (by default not run, you must explicitly include MicroBenchmarks in TEST_SUITE_SUBDIRS)
Reviewers: dberris, chandlerc, dberlin, MatzeB
Reviewed By: dberris, MatzeB
Subscribers: hfinkel, javed.absar, krytarowski, MatzeB, kristof.beyls, srhines, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D32272
Patch by Eizan Miyamoto (eizan)
llvm-svn: 307017
85 files changed