Add support for building with Bazel. (#533)

* Add myself to CONTRIBUTORS under the corp CLA for Stripe, Inc.

* Add support for building with Bazel.

Limitations compared to existing CMake rules:
* Defaults to using C++11 `<regex>`, with an override via Bazel flag
  `--define` of `google_benchmark.have_regex`. The TravisCI config sets
  the regex implementation to `posix` because it uses ancient compilers.
* Debug vs Opt mode can't be set per test. TravisCI runs all the tests
  in debug mode to satisfy `diagnostics_test`, which depends on `CHECK`
  being live.

* Set Bazel workspace name so other repos can refer to it by stable name.

This is recommended by the Bazel style guide to avoid each dependent
workspace defining its own name for the dependency.

.gitignore

@@ -41,6 +41,9 @@ build.ninja
 install_manifest.txt
 rules.ninja
 
+# bazel output symlinks.
+bazel-*
+
 # out-of-source build top-level folders.
 build/
 _build/

.travis.yml

@@ -159,11 +159,22 @@ install:
       brew update;
       brew install gcc@7;
     fi
+  - if [ "${TRAVIS_OS_NAME}" == "linux" ]; then
+      sudo apt-get update -qq;
+      sudo apt-get install -qq unzip;
+      wget https://github.com/bazelbuild/bazel/releases/download/0.10.1/bazel-0.10.1-installer-linux-x86_64.sh --output-document bazel-installer.sh;
+      sudo bash bazel-installer.sh;
+    fi
+  - if [ "${TRAVIS_OS_NAME}" == "osx" ]; then
+      curl -L -o bazel-installer.sh https://github.com/bazelbuild/bazel/releases/download/0.10.1/bazel-0.10.1-installer-darwin-x86_64.sh;
+      sudo bash bazel-installer.sh;
+    fi
 
 script:
   - cmake -DCMAKE_C_COMPILER=${C_COMPILER} -DCMAKE_CXX_COMPILER=${COMPILER} -DCMAKE_BUILD_TYPE=${BUILD_TYPE} -DCMAKE_CXX_FLAGS="${EXTRA_FLAGS}" -DBENCHMARK_DOWNLOAD_DEPENDENCIES=ON -DBENCHMARK_BUILD_32_BITS=${BUILD_32_BITS} ..
   - make
   - ctest -C ${BUILD_TYPE} --output-on-failure
+  - bazel test -c dbg --define google_benchmark.have_regex=posix --announce_rc --verbose_failures --test_output=errors --keep_going //test/...
 
 after_success:
   - if [ "${BUILD_TYPE}" == "Coverage" -a "${TRAVIS_OS_NAME}" == "linux" ]; then

AUTHORS

@@ -39,6 +39,7 @@ Radoslav Yovchev <radoslav.tm@gmail.com>
 Roman Lebedev <lebedev.ri@gmail.com>
 Shuo Chen <chenshuo@chenshuo.com>
 Steinar H. Gunderson <sgunderson@bigfoot.com>
+Stripe, Inc.
 Yixuan Qiu <yixuanq@gmail.com>
 Yusuke Suzuki <utatane.tea@gmail.com>
 Zbigniew Skowron <zbychs@gmail.com>

BUILD.bazel

@@ -0,0 +1,21 @@
+licenses(["notice"])
+
+load("//bazel:have_regex.bzl", "have_regex_copts")
+
+cc_library(
+    name = "benchmark",
+    srcs = glob([
+        "src/*.cc",
+        "src/*.h",
+    ]),
+    hdrs = ["include/benchmark/benchmark.h"],
+    copts = have_regex_copts(),
+    strip_include_prefix = "include",
+    visibility = ["//visibility:public"],
+)
+
+cc_library(
+    name = "benchmark_internal_headers",
+    hdrs = glob(["src/*.h"]),
+    visibility = ["//test:__pkg__"],
+)

CONTRIBUTORS

@@ -38,6 +38,7 @@ Ismael Jimenez Martinez <ismael.jimenez.martinez@gmail.com>
 Jern-Kuan Leong <jernkuan@gmail.com>
 JianXiong Zhou <zhoujianxiong2@gmail.com>
 Joao Paulo Magalhaes <joaoppmagalhaes@gmail.com>
+John Millikin <jmillikin@stripe.com>
 Jussi Knuuttila <jussi.knuuttila@gmail.com>
 Kai Wolf <kai.wolf@gmail.com>
 Kishan Kumar <kumar.kishan@outlook.com>

WORKSPACE

@@ -0,0 +1,9 @@
+workspace(name = "com_github_google_benchmark")
+
+load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
+
+git_repository(
+    name = "com_google_googletest",
+    commit = "3f0cf6b62ad1eb50d8736538363d3580dd640c3e",  # HEAD
+    remote = "https://github.com/google/googletest",
+)

bazel/BUILD

@@ -0,0 +1,16 @@
+package(default_visibility = ["//:__subpackages__"])
+
+config_setting(
+    name = "have_std_regex",
+    values = {"define": "google_benchmark.have_regex=std"},
+)
+
+config_setting(
+    name = "have_posix_regex",
+    values = {"define": "google_benchmark.have_regex=posix"},
+)
+
+config_setting(
+    name = "have_gnu_posix_regex",
+    values = {"define": "google_benchmark.have_regex=gnu_posix"},
+)

bazel/have_regex.bzl

@@ -0,0 +1,7 @@
+def have_regex_copts():
+  return select({
+      "//bazel:have_std_regex": ["-DHAVE_STD_REGEX"],
+      "//bazel:have_posix_regex": ["-DHAVE_POSIX_REGEX"],
+      "//bazel:have_gnu_posix_regex": ["-DHAVE_GNU_POSIX_REGEX"],
+      "//conditions:default": ["-DHAVE_STD_REGEX"],
+  })

test/BUILD

@@ -0,0 +1,47 @@
+load("//bazel:have_regex.bzl", "have_regex_copts")
+
+NEEDS_GTEST_MAIN = [
+    "statistics_test.cc",
+]
+
+TEST_COPTS = [
+    "-pedantic",
+    "-pedantic-errors",
+    "-std=c++11",
+] + have_regex_copts()
+
+TEST_ARGS = ["--benchmark_min_time=0.01"]
+
+cc_library(
+    name = "output_test_helper",
+    testonly = 1,
+    srcs = ["output_test_helper.cc"],
+    hdrs = ["output_test.h"],
+    copts = TEST_COPTS,
+    deps = [
+        "//:benchmark",
+        "//:benchmark_internal_headers",
+    ],
+)
+
+[cc_test(
+    name = test_src[:-len(".cc")],
+    size = "small",
+    srcs = [test_src],
+    args = TEST_ARGS + ({
+        "user_counters_tabular_test.cc": ["--benchmark_counters_tabular=true"],
+    }).get(test_src, []),
+    copts = TEST_COPTS + ({
+        "cxx03_test.cc": ["-std=c++03"],
+        # Some of the issues with DoNotOptimize only occur when optimization is enabled
+        "donotoptimize_test.cc": ["-O3"],
+    }).get(test_src, []),
+    deps = [
+        ":output_test_helper",
+        "//:benchmark",
+        "//:benchmark_internal_headers",
+        "@com_google_googletest//:gtest",
+    ] + (
+        ["@com_google_googletest//:gtest_main"] if (test_src in NEEDS_GTEST_MAIN) else []
+    ),
+) for test_src in glob(["*_test.cc"])]