Update in-tree Google Benchmark to current ToT.

I've put some work into the Google Benchmark library in order to make it easier
to benchmark libc++. These changes have already been upstreamed into
Google Benchmark and this patch applies the changes to the in-tree version.

The main improvement in the addition of a 'compare_bench.py' script which
makes it very easy to compare benchmarks. For example to compare the native
STL to libc++ you would run:

`$ compare_bench.py ./util_smartptr.native.out ./util_smartptr.libcxx.out`

And the output would look like:

RUNNING: ./util_smartptr.native.out
Benchmark                          Time           CPU Iterations
----------------------------------------------------------------
BM_SharedPtrCreateDestroy         62 ns         62 ns   10937500
BM_SharedPtrIncDecRef             31 ns         31 ns   23972603
BM_WeakPtrIncDecRef               28 ns         28 ns   23648649
RUNNING: ./util_smartptr.libcxx.out
Benchmark                          Time           CPU Iterations
----------------------------------------------------------------
BM_SharedPtrCreateDestroy         46 ns         46 ns   14957265
BM_SharedPtrIncDecRef             31 ns         31 ns   22435897
BM_WeakPtrIncDecRef               34 ns         34 ns   21084337
Comparing ./util_smartptr.native.out to ./util_smartptr.libcxx.out
Benchmark                          Time           CPU
-----------------------------------------------------
BM_SharedPtrCreateDestroy         -0.26         -0.26
BM_SharedPtrIncDecRef             +0.00         +0.00
BM_WeakPtrIncDecRef               +0.21         +0.21

llvm-svn: 278147

1 files changed, 8 insertions, 0 deletions

diff --git a/libcxx/utils/google-benchmark/tools/gbench/__init__.py b/libcxx/utils/google-benchmark/tools/gbench/__init__.py
new file mode 100644
index 00000000000..fce1a1acfbb
--- /dev/null
+++ b/libcxx/utils/google-benchmark/tools/gbench/__init__.py
@@ -0,0 +1,8 @@
+"""Google Benchmark tooling"""
+
+__author__ = 'Eric Fiselier'
+__email__ = 'eric@efcs.ca'
+__versioninfo__ = (0, 5, 0)
+__version__ = '.'.join(str(v) for v in __versioninfo__) + 'dev'
+
+__all__ = []