Support .rs and .fs files in cc_* module srcs lists

Translate .rs and .fs files to .cpp files using llvm-rs-cc.

Test: builds
Change-Id: I242cea0d09c9985730a512cec7705c3f1479f4ed
diff --git a/cc/rs.go b/cc/rs.go
new file mode 100644
index 0000000..fda2469
--- /dev/null
+++ b/cc/rs.go
@@ -0,0 +1,114 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// 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 cc
+
+import (
+	"android/soong/android"
+	"strings"
+
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
+)
+
+func init() {
+	pctx.HostBinToolVariable("rsCmd", "llvm-rs-cc")
+}
+
+var rsCppCmdLine = strings.Replace(`
+${rsCmd} -o ${outDir} -d ${outDir} -a ${out} -MD -reflect-c++ ${rsFlags} $in &&
+(echo '${out}: \' && cat ${depFiles} | awk 'start { sub(/( \\)?$$/, " \\"); print } /:/ { start=1 }') > ${out}.d &&
+touch $out
+`, "\n", "", -1)
+
+var (
+	rsCpp = pctx.AndroidStaticRule("rsCpp",
+		blueprint.RuleParams{
+			Command:     rsCppCmdLine,
+			CommandDeps: []string{"$rsCmd"},
+			Depfile:     "${out}.d",
+			Deps:        blueprint.DepsGCC,
+			Description: "rsCpp $out",
+		},
+		"depFiles", "outDir", "rsFlags", "stampFile")
+)
+
+// Takes a path to a .rs or .fs file, and returns a path to a generated ScriptC_*.cpp file
+// This has to match the logic in llvm-rs-cc in DetermineOutputFile.
+func rsGeneratedCppFile(ctx android.ModuleContext, rsFile android.Path) android.WritablePath {
+	fileName := strings.TrimSuffix(rsFile.Base(), rsFile.Ext())
+	return android.PathForModuleGen(ctx, "rs", "ScriptC_"+fileName+".cpp")
+}
+
+func rsGeneratedDepFile(ctx android.ModuleContext, rsFile android.Path) android.WritablePath {
+	fileName := strings.TrimSuffix(rsFile.Base(), rsFile.Ext())
+	return android.PathForModuleGen(ctx, "rs", fileName+".d")
+}
+
+func rsGenerateCpp(ctx android.ModuleContext, rsFiles android.Paths, rsFlags string) android.Paths {
+	stampFile := android.PathForModuleGen(ctx, "rs", "rs.stamp")
+	depFiles := make(android.WritablePaths, len(rsFiles))
+	cppFiles := make(android.WritablePaths, len(rsFiles))
+	for i, rsFile := range rsFiles {
+		depFiles[i] = rsGeneratedDepFile(ctx, rsFile)
+		cppFiles[i] = rsGeneratedCppFile(ctx, rsFile)
+	}
+
+	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
+		Rule:            rsCpp,
+		Output:          stampFile,
+		ImplicitOutputs: cppFiles,
+		Inputs:          rsFiles,
+		Args: map[string]string{
+			"rsFlags":  rsFlags,
+			"outDir":   android.PathForModuleGen(ctx, "rs").String(),
+			"depFiles": strings.Join(depFiles.Strings(), " "),
+		},
+	})
+
+	return android.Paths{stampFile}
+}
+
+func rsFlags(ctx ModuleContext, flags Flags, properties *BaseCompilerProperties) Flags {
+	targetApi := proptools.String(properties.Renderscript.Target_api)
+	if targetApi == "" && ctx.sdk() {
+		switch ctx.sdkVersion() {
+		case "current", "system_current", "test_current":
+			// Nothing
+		default:
+			targetApi = ctx.sdkVersion()
+		}
+	}
+
+	if targetApi != "" {
+		flags.rsFlags = append(flags.rsFlags, "-target-api "+targetApi)
+	}
+
+	flags.rsFlags = append(flags.rsFlags, "-Wall", "-Werror")
+	flags.rsFlags = append(flags.rsFlags, properties.Renderscript.Flags...)
+	if ctx.Arch().ArchType.Multilib == "lib64" {
+		flags.rsFlags = append(flags.rsFlags, "-m64")
+	} else {
+		flags.rsFlags = append(flags.rsFlags, "-m32")
+	}
+	flags.rsFlags = append(flags.rsFlags, "${config.RsGlobalIncludes}")
+
+	rootRsIncludeDirs := android.PathsForSource(ctx, properties.Renderscript.Include_dirs)
+	flags.rsFlags = append(flags.rsFlags, includeDirsToFlags(rootRsIncludeDirs))
+
+	flags.GlobalFlags = append(flags.GlobalFlags,
+		"-I"+android.PathForModuleGen(ctx, "rs").String())
+
+	return flags
+}