[opt-viewer] Add support for libYAML for faster parsing
This results in a speed-up of over 6x on sqlite3.
Before:
$ time -p /org/llvm/utils/opt-viewer/opt-viewer.py ./MultiSource/Applications/sqlite3/CMakeFiles/sqlite3.dir/sqlite3.c.opt.yaml html
real 415.07
user 410.00
sys 4.66
After with libYAML:
$ time -p /org/llvm/utils/opt-viewer/opt-viewer.py ./MultiSource/Applications/sqlite3/CMakeFiles/sqlite3.dir/sqlite3.c.opt.yaml html
real 63.96
user 60.03
sys 3.67
I followed these steps to get libYAML working with PyYAML: http://rmcgibbo.github.io/blog/2013/05/23/faster-yaml-parsing-with-libyaml/
llvm-svn: 286942