Add AArch64 device Rust toolchain.

Bug: 141207434
Test: build example rust device module.
Change-Id: I0932a614942bf4a4d4b6c153fcc4fc79c7f202bd

rust/config/arm64_device.go

@@ -0,0 +1,92 @@
+// 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 config
+
+import (
+	"strings"
+
+	"android/soong/android"
+)
+
+var (
+	Arm64RustFlags            = []string{}
+	Arm64ArchFeatureRustFlags = map[string][]string{}
+	Arm64LinkFlags            = []string{
+		"-Wl,--icf=safe",
+		"-Wl,-z,max-page-size=4096",
+
+		"-Wl,-execute-only",
+	}
+
+	Arm64ArchVariantRustFlags = map[string][]string{
+		"armv8-a":  []string{},
+		"armv8-2a": []string{},
+	}
+)
+
+func init() {
+	registerToolchainFactory(android.Android, android.Arm64, Arm64ToolchainFactory)
+
+	pctx.StaticVariable("Arm64ToolchainRustFlags", strings.Join(Arm64RustFlags, " "))
+	pctx.StaticVariable("Arm64ToolchainLinkFlags", strings.Join(Arm64LinkFlags, " "))
+
+	for variant, rustFlags := range Arm64ArchVariantRustFlags {
+		pctx.StaticVariable("Arm64"+variant+"VariantRustFlags",
+			strings.Join(rustFlags, " "))
+	}
+
+}
+
+type toolchainArm64 struct {
+	toolchain64Bit
+	toolchainRustFlags string
+}
+
+func (t *toolchainArm64) RustTriple() string {
+	return "aarch64-linux-android"
+}
+
+func (t *toolchainArm64) ToolchainLinkFlags() string {
+	return "${config.DeviceGlobalLinkFlags} ${config.Arm64ToolchainLinkFlags}"
+}
+
+func (t *toolchainArm64) ToolchainRustFlags() string {
+	return t.toolchainRustFlags
+}
+
+func (t *toolchainArm64) RustFlags() string {
+	return "${config.Arm64ToolchainRustFlags}"
+}
+
+func (t *toolchainArm64) Supported() bool {
+	return true
+}
+
+func Arm64ToolchainFactory(arch android.Arch) Toolchain {
+	toolchainRustFlags := []string{
+		"${config.Arm64ToolchainRustFlags}",
+		"${config.Arm64" + arch.ArchVariant + "VariantRustFlags}",
+	}
+
+	toolchainRustFlags = append(toolchainRustFlags, deviceGlobalRustFlags...)
+
+	for _, feature := range arch.ArchFeatures {
+		toolchainRustFlags = append(toolchainRustFlags, Arm64ArchFeatureRustFlags[feature]...)
+	}
+
+	return &toolchainArm64{
+		toolchainRustFlags: strings.Join(toolchainRustFlags, " "),
+	}
+}