Add Rust support to Soong.

Adds support to Soong for building rust modules. This currently only
supports x86_64 device and x86 linux host targets. The functionality
is sufficient to build crosvm.

Bug: 136189233
Test: Test module builds.
Test: crosvm builds.
Change-Id: I6ea04615834a6d673578ab10ea1a2eb04259fe09

1 files changed, 110 insertions, 0 deletions

diff --git a/rust/binary.go b/rust/binary.go
new file mode 100644
index 000000000..279c6f50f
--- /dev/null
+++ b/rust/binary.go
@@ -0,0 +1,110 @@
+// Copyright 2019 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"
+	"android/soong/rust/config"
+)
+
+func init() {
+	android.RegisterModuleType("rust_binary", RustBinaryFactory)
+	android.RegisterModuleType("rust_binary_host", RustBinaryHostFactory)
+}
+
+type BinaryCompilerProperties struct {
+	// path to the main source file that contains the program entry point (e.g. src/main.rs)
+	Srcs []string `android:"path,arch_variant"`
+
+	// passes -C prefer-dynamic to rustc, which tells it to dynamically link the stdlib (assuming it has no dylib dependencies already)
+	Prefer_dynamic *bool
+}
+
+type binaryDecorator struct {
+	*baseCompiler
+
+	Properties           BinaryCompilerProperties
+	distFile             android.OptionalPath
+	unstrippedOutputFile android.Path
+}
+
+var _ compiler = (*binaryDecorator)(nil)
+
+// rust_binary produces a binary that is runnable on a device.
+func RustBinaryFactory() android.Module {
+	module, _ := NewRustBinary(android.HostAndDeviceSupported)
+	return module.Init()
+}
+
+func RustBinaryHostFactory() android.Module {
+	module, _ := NewRustBinary(android.HostSupported)
+	return module.Init()
+}
+
+func NewRustBinary(hod android.HostOrDeviceSupported) (*Module, *binaryDecorator) {
+	module := newModule(hod, android.MultilibFirst)
+
+	binary := &binaryDecorator{
+		baseCompiler: NewBaseCompiler("bin", ""),
+	}
+
+	module.compiler = binary
+
+	return module, binary
+}
+
+func (binary *binaryDecorator) preferDynamic() bool {
+	return Bool(binary.Properties.Prefer_dynamic)
+}
+
+func (binary *binaryDecorator) compilerFlags(ctx ModuleContext, flags Flags) Flags {
+	flags = binary.baseCompiler.compilerFlags(ctx, flags)
+	if binary.preferDynamic() {
+		flags.RustFlags = append(flags.RustFlags, "-C prefer-dynamic")
+	}
+	return flags
+}
+
+func (binary *binaryDecorator) compilerDeps(ctx DepsContext, deps Deps) Deps {
+	deps = binary.baseCompiler.compilerDeps(ctx, deps)
+
+	if binary.preferDynamic() || len(deps.Dylibs) > 0 {
+		for _, stdlib := range config.Stdlibs {
+			deps.Dylibs = append(deps.Dylibs, stdlib+"_"+ctx.toolchain().RustTriple())
+		}
+	}
+
+	return deps
+}
+
+func (binary *binaryDecorator) compilerProps() []interface{} {
+	return append(binary.baseCompiler.compilerProps(),
+		&binary.Properties)
+}
+
+func (binary *binaryDecorator) compile(ctx ModuleContext, flags Flags, deps PathDeps) android.Path {
+	fileName := binary.getStem(ctx) + ctx.toolchain().ExecutableSuffix()
+
+	srcPath := srcPathFromModuleSrcs(ctx, binary.Properties.Srcs)
+
+	outputFile := android.PathForModuleOut(ctx, fileName)
+	binary.unstrippedOutputFile = outputFile
+
+	flags.RustFlags = append(flags.RustFlags, deps.depFlags...)
+
+	TransformSrcToBinary(ctx, srcPath, deps, flags, outputFile, deps.linkDirs)
+
+	return outputFile
+}