Add x86 device output for Rust

* Copy current configuration from
  rust/config/x86_64_device.go and
  cc/config/x86_device.go.

Bug: 145608833
Test: build rust modules for aosp_x86-userdebug
Change-Id: Ie4951dd4703596f8e503d813a6c4ac03c1f20980
diff --git a/rust/config/x86_device.go b/rust/config/x86_device.go
new file mode 100644
index 0000000..ec19b3c
--- /dev/null
+++ b/rust/config/x86_device.go
@@ -0,0 +1,97 @@
+// 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 (
+	x86RustFlags            = []string{}
+	x86ArchFeatureRustFlags = map[string][]string{}
+	x86LinkFlags            = []string{}
+
+	x86ArchVariantRustFlags = map[string][]string{
+		"":            []string{},
+		"atom":        []string{"-C target-cpu=atom"},
+		"broadwell":   []string{"-C target-cpu=broadwell"},
+		"haswell":     []string{"-C target-cpu=haswell"},
+		"ivybridge":   []string{"-C target-cpu=ivybridge"},
+		"sandybridge": []string{"-C target-cpu=sandybridge"},
+		"silvermont":  []string{"-C target-cpu=silvermont"},
+		"skylake":     []string{"-C target-cpu=skylake"},
+		//TODO: Add target-cpu=stoneyridge when rustc supports it.
+		"stoneyridge": []string{""},
+		// use prescott for x86_64, like cc/config/x86_device.go
+		"x86_64": []string{"-C target-cpu=prescott"},
+	}
+)
+
+func init() {
+	registerToolchainFactory(android.Android, android.X86, x86ToolchainFactory)
+
+	pctx.StaticVariable("X86ToolchainRustFlags", strings.Join(x86RustFlags, " "))
+	pctx.StaticVariable("X86ToolchainLinkFlags", strings.Join(x86LinkFlags, " "))
+
+	for variant, rustFlags := range x86ArchVariantRustFlags {
+		pctx.StaticVariable("X86"+variant+"VariantRustFlags",
+			strings.Join(rustFlags, " "))
+	}
+
+}
+
+type toolchainX86 struct {
+	toolchain32Bit
+	toolchainRustFlags string
+}
+
+func (t *toolchainX86) RustTriple() string {
+	return "i686-linux-android"
+}
+
+func (t *toolchainX86) ToolchainLinkFlags() string {
+	return "${config.DeviceGlobalLinkFlags} ${config.X86ToolchainLinkFlags}"
+}
+
+func (t *toolchainX86) ToolchainRustFlags() string {
+	return t.toolchainRustFlags
+}
+
+func (t *toolchainX86) RustFlags() string {
+	return "${config.X86ToolchainRustFlags}"
+}
+
+func (t *toolchainX86) Supported() bool {
+	return true
+}
+
+func x86ToolchainFactory(arch android.Arch) Toolchain {
+	toolchainRustFlags := []string{
+		"${config.X86ToolchainRustFlags}",
+		"${config.X86" + arch.ArchVariant + "VariantRustFlags}",
+	}
+
+	toolchainRustFlags = append(toolchainRustFlags, deviceGlobalRustFlags...)
+
+	for _, feature := range arch.ArchFeatures {
+		toolchainRustFlags = append(toolchainRustFlags, x86ArchFeatureRustFlags[feature]...)
+	}
+
+	return &toolchainX86{
+		toolchainRustFlags: strings.Join(toolchainRustFlags, " "),
+	}
+}