Add rust_benchmark module to soong.

This commit adds rust_benchmark and rust_benchmark_host commands to
soong. Respectively running rust benchmarks on device and host. Currently
only criterion based benchmarks are supported and criterion library is
automatically linked.

Test: atest <module with rust_benchmark defined>
Bug: 155309706
Change-Id: I6edfc2b4bf30b1163fe59b8c2ecdcd4e7125e7b9
diff --git a/rust/benchmark.go b/rust/benchmark.go
new file mode 100644
index 0000000..6e4fb85
--- /dev/null
+++ b/rust/benchmark.go
@@ -0,0 +1,89 @@
+// Copyright 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package rust
+
+import (
+	"android/soong/android"
+)
+
+type BenchmarkProperties struct {
+}
+
+type benchmarkDecorator struct {
+	*binaryDecorator
+	Properties BenchmarkProperties
+	testConfig android.Path
+}
+
+func NewRustBenchmark(hod android.HostOrDeviceSupported) (*Module, *benchmarkDecorator) {
+	// Build both 32 and 64 targets for device benchmarks.
+	// Cannot build both for host benchmarks yet if the benchmark depends on
+	// something like proc-macro2 that cannot be built for both.
+	multilib := android.MultilibBoth
+	if hod != android.DeviceSupported && hod != android.HostAndDeviceSupported {
+		multilib = android.MultilibFirst
+	}
+	module := newModule(hod, multilib)
+
+	benchmark := &benchmarkDecorator{
+		binaryDecorator: &binaryDecorator{
+			baseCompiler: NewBaseCompiler("nativebench", "nativebench64", InstallInData),
+		},
+	}
+
+	module.compiler = benchmark
+	module.AddProperties(&benchmark.Properties)
+	return module, benchmark
+}
+
+func init() {
+	android.RegisterModuleType("rust_benchmark", RustBenchmarkFactory)
+	android.RegisterModuleType("rust_benchmark_host", RustBenchmarkHostFactory)
+}
+
+func RustBenchmarkFactory() android.Module {
+	module, _ := NewRustBenchmark(android.HostAndDeviceSupported)
+	return module.Init()
+}
+
+func RustBenchmarkHostFactory() android.Module {
+	module, _ := NewRustBenchmark(android.HostSupported)
+	return module.Init()
+}
+
+func (benchmark *benchmarkDecorator) autoDep(ctx android.BottomUpMutatorContext) autoDep {
+	return rlibAutoDep
+}
+
+func (benchmark *benchmarkDecorator) stdLinkage(ctx *depsContext) RustLinkage {
+	return RlibLinkage
+}
+
+func (benchmark *benchmarkDecorator) compilerFlags(ctx ModuleContext, flags Flags) Flags {
+	flags = benchmark.binaryDecorator.compilerFlags(ctx, flags)
+	return flags
+}
+
+func (benchmark *benchmarkDecorator) compilerDeps(ctx DepsContext, deps Deps) Deps {
+	deps = benchmark.binaryDecorator.compilerDeps(ctx, deps)
+
+	deps.Rustlibs = append(deps.Rustlibs, "libcriterion")
+
+	return deps
+}
+
+func (benchmark *benchmarkDecorator) compilerProps() []interface{} {
+	return append(benchmark.binaryDecorator.compilerProps(), &benchmark.Properties)
+}