Run JMH benchmarks using bazel

The benchmarks can be built and run using bazel by running:

$ bazel run //org.eclipse.jgit.benchmarks:benchmarks

Change-Id: I6679750eaa0f2be30ed9d45036e013b0ea4fcc86
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

WORKSPACE

@@ -22,6 +22,36 @@ load(
     "maven_jar",
 )
 
+JMH_VERS = "1.21"
+
+maven_jar(
+    name = "jmh-core",
+    artifact = "org.openjdk.jmh:jmh-core:" + JMH_VERS,
+    attach_source = False,
+    sha1 = "442447101f63074c61063858033fbfde8a076873",
+)
+
+maven_jar(
+    name = "jmh-annotations",
+    artifact = "org.openjdk.jmh:jmh-generator-annprocess:" + JMH_VERS,
+    attach_source = False,
+    sha1 = "7aac374614a8a76cad16b91f1a4419d31a7dcda3",
+)
+
+maven_jar(
+    name = "jopt",
+    artifact = "net.sf.jopt-simple:jopt-simple:5.0.4",
+    attach_source = False,
+    sha1 = "4fdac2fbe92dfad86aa6e9301736f6b4342a3f5c",
+)
+
+maven_jar(
+    name = "math3",
+    artifact = "org.apache.commons:commons-math3:3.6.1",
+    attach_source = False,
+    sha1 = "e4ba98f1d4b3c80ec46392f25e094a6a2e58fcbf",
+)
+
 maven_jar(
     name = "jsch",
     artifact = "com.jcraft:jsch:0.1.55",

lib/jmh/BUILD

@@ -0,0 +1,12 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
+java_library(
+    name = "jmh",
+    visibility = ["//visibility:public"],
+    exports = [
+        "@jmh-annotations//jar",
+        "@jmh-core//jar",
+        "@jopt//jar",
+        "@math3//jar",
+    ],
+)

org.eclipse.jgit.benchmarks/BUILD

@@ -0,0 +1,13 @@
+load("//tools:bzl/jmh.bzl", "jmh_java_benchmarks")
+
+SRCS = glob(
+    ["src/**/*.java"],
+)
+
+jmh_java_benchmarks(
+    name = "benchmarks",
+    srcs = SRCS,
+    deps = [
+        "//org.eclipse.jgit:jgit",
+    ],
+)

tools/bzl/jmh.bzl

@@ -0,0 +1,66 @@
+# Copyright (C) 2019, Matthias Sohn <matthias.sohn@sap.com>
+# and other copyright owners as documented in the project's IP log.
+#
+# This program and the accompanying materials are made available
+# under the terms of the Eclipse Distribution License v1.0 which
+# accompanies this distribution, is reproduced below, and is
+# available at http://www.eclipse.org/org/documents/edl-v10.php
+#
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or
+# without modification, are permitted provided that the following
+# conditions are met:
+#
+# - Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+#
+# - Redistributions in binary form must reproduce the above
+#   copyright notice, this list of conditions and the following
+#   disclaimer in the documentation and/or other materials provided
+#   with the distribution.
+#
+# - Neither the name of the Eclipse Foundation, Inc. nor the
+#   names of its contributors may be used to endorse or promote
+#   products derived from this software without specific prior
+#   written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+# CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# Definitions to run jmh microbenchmarks
+
+def jmh_java_benchmarks(name, srcs, deps = [], tags = [], plugins = [], **kwargs):
+    """Builds runnable JMH benchmarks.
+    This rule builds a runnable target for one or more JMH benchmarks
+    specified as srcs. It takes the same arguments as java_binary,
+    except for main_class.
+    """
+    plugin_name = "_{}_jmh_annotation_processor".format(name)
+    native.java_plugin(
+        name = plugin_name,
+        deps = ["//lib/jmh:jmh"],
+        processor_class = "org.openjdk.jmh.generators.BenchmarkProcessor",
+        visibility = ["//visibility:private"],
+        tags = tags,
+    )
+    native.java_binary(
+        name = name,
+        srcs = srcs,
+        main_class = "org.openjdk.jmh.Main",
+        deps = deps + ["//lib/jmh:jmh"],
+        plugins = plugins + [plugin_name],
+        tags = tags,
+        **kwargs
+    )