Add container property to aconfig_declarations.

Bug: 311155208
Test: Unit test
Change-Id: I7b187138856d0144203961e82b6dad5e2f8eed9d
diff --git a/aconfig/codegen/Android.bp b/aconfig/codegen/Android.bp
new file mode 100644
index 0000000..494f7e6
--- /dev/null
+++ b/aconfig/codegen/Android.bp
@@ -0,0 +1,32 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+bootstrap_go_package {
+    name: "soong-aconfig-codegen",
+    pkgPath: "android/soong/aconfig/codegen",
+    deps: [
+        "blueprint",
+        "blueprint-pathtools",
+        "sbox_proto",
+        "soong",
+        "soong-aconfig",
+        "soong-android",
+        "soong-bazel",
+        "soong-java",
+        "soong-rust",
+    ],
+    srcs: [
+        "cc_aconfig_library.go",
+        "init.go",
+        "java_aconfig_library.go",
+        "rust_aconfig_library.go",
+        "testing.go",
+    ],
+    testSrcs: [
+        "java_aconfig_library_test.go",
+        "cc_aconfig_library_test.go",
+        "rust_aconfig_library_test.go",
+    ],
+    pluginFor: ["soong_build"],
+}
diff --git a/aconfig/codegen/cc_aconfig_library.go b/aconfig/codegen/cc_aconfig_library.go
new file mode 100644
index 0000000..7b68844
--- /dev/null
+++ b/aconfig/codegen/cc_aconfig_library.go
@@ -0,0 +1,184 @@
+// Copyright 2023 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 codegen
+
+import (
+	"android/soong/aconfig"
+	"android/soong/android"
+	"android/soong/bazel"
+	"android/soong/cc"
+
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
+
+	"fmt"
+	"strings"
+)
+
+type ccDeclarationsTagType struct {
+	blueprint.BaseDependencyTag
+}
+
+var ccDeclarationsTag = ccDeclarationsTagType{}
+
+const baseLibDep = "server_configurable_flags"
+
+type CcAconfigLibraryProperties struct {
+	// name of the aconfig_declarations module to generate a library for
+	Aconfig_declarations string
+
+	// default mode is "production", the other accepted modes are:
+	// "test": to generate test mode version of the library
+	// "exported": to generate exported mode version of the library
+	// an error will be thrown if the mode is not supported
+	Mode *string
+}
+
+type CcAconfigLibraryCallbacks struct {
+	properties *CcAconfigLibraryProperties
+
+	generatedDir android.WritablePath
+	headerDir    android.WritablePath
+	generatedCpp android.WritablePath
+	generatedH   android.WritablePath
+}
+
+func CcAconfigLibraryFactory() android.Module {
+	callbacks := &CcAconfigLibraryCallbacks{
+		properties: &CcAconfigLibraryProperties{},
+	}
+	return cc.GeneratedCcLibraryModuleFactory("cc_aconfig_library", callbacks)
+}
+
+func (this *CcAconfigLibraryCallbacks) GeneratorInit(ctx cc.BaseModuleContext) {
+}
+
+func (this *CcAconfigLibraryCallbacks) GeneratorProps() []interface{} {
+	return []interface{}{this.properties}
+}
+
+func (this *CcAconfigLibraryCallbacks) GeneratorDeps(ctx cc.DepsContext, deps cc.Deps) cc.Deps {
+	// Add a dependency for the declarations module
+	declarations := this.properties.Aconfig_declarations
+	if len(declarations) == 0 {
+		ctx.PropertyErrorf("aconfig_declarations", "aconfig_declarations property required")
+	} else {
+		ctx.AddDependency(ctx.Module(), ccDeclarationsTag, declarations)
+	}
+
+	// Add a dependency for the aconfig flags base library
+	deps.SharedLibs = append(deps.SharedLibs, baseLibDep)
+	// TODO: It'd be really nice if we could reexport this library and not make everyone do it.
+
+	return deps
+}
+
+func (this *CcAconfigLibraryCallbacks) GeneratorSources(ctx cc.ModuleContext) cc.GeneratedSource {
+	result := cc.GeneratedSource{}
+
+	// Get the values that came from the global RELEASE_ACONFIG_VALUE_SETS flag
+	declarationsModules := ctx.GetDirectDepsWithTag(ccDeclarationsTag)
+	if len(declarationsModules) != 1 {
+		panic(fmt.Errorf("Exactly one aconfig_declarations property required"))
+	}
+	declarations := ctx.OtherModuleProvider(declarationsModules[0], aconfig.DeclarationsProviderKey).(aconfig.DeclarationsProviderData)
+
+	// Figure out the generated file paths.  This has to match aconfig's codegen_cpp.rs.
+	this.generatedDir = android.PathForModuleGen(ctx)
+
+	this.headerDir = android.PathForModuleGen(ctx, "include")
+	result.IncludeDirs = []android.Path{this.headerDir}
+	result.ReexportedDirs = []android.Path{this.headerDir}
+
+	basename := strings.ReplaceAll(declarations.Package, ".", "_")
+
+	this.generatedCpp = android.PathForModuleGen(ctx, basename+".cc")
+	result.Sources = []android.Path{this.generatedCpp}
+
+	this.generatedH = android.PathForModuleGen(ctx, "include", basename+".h")
+	result.Headers = []android.Path{this.generatedH}
+
+	return result
+}
+
+func (this *CcAconfigLibraryCallbacks) GeneratorFlags(ctx cc.ModuleContext, flags cc.Flags, deps cc.PathDeps) cc.Flags {
+	return flags
+}
+
+func (this *CcAconfigLibraryCallbacks) GeneratorBuildActions(ctx cc.ModuleContext, flags cc.Flags, deps cc.PathDeps) {
+	// Get the values that came from the global RELEASE_ACONFIG_VALUE_SETS flag
+	declarationsModules := ctx.GetDirectDepsWithTag(ccDeclarationsTag)
+	if len(declarationsModules) != 1 {
+		panic(fmt.Errorf("Exactly one aconfig_declarations property required"))
+	}
+	declarations := ctx.OtherModuleProvider(declarationsModules[0], aconfig.DeclarationsProviderKey).(aconfig.DeclarationsProviderData)
+
+	mode := proptools.StringDefault(this.properties.Mode, "production")
+	if !isModeSupported(mode) {
+		ctx.PropertyErrorf("mode", "%q is not a supported mode", mode)
+	}
+
+	ctx.Build(pctx, android.BuildParams{
+		Rule:  cppRule,
+		Input: declarations.IntermediatePath,
+		Outputs: []android.WritablePath{
+			this.generatedCpp,
+			this.generatedH,
+		},
+		Description: "cc_aconfig_library",
+		Args: map[string]string{
+			"gendir": this.generatedDir.String(),
+			"mode":   mode,
+		},
+	})
+}
+
+type bazelCcAconfigLibraryAttributes struct {
+	cc.SdkAttributes
+	Aconfig_declarations bazel.LabelAttribute
+	Dynamic_deps         bazel.LabelListAttribute
+}
+
+// Convert the cc_aconfig_library module to bazel.
+//
+// This method is called from cc.ConvertWithBp2build to actually convert the
+// cc_aconfig_library module. This is necessary since the factory method of this
+// module type returns a cc library and the bp2build conversion is called on the
+// cc library type.
+
+func (this *CcAconfigLibraryCallbacks) GeneratorBp2build(ctx android.Bp2buildMutatorContext, module *cc.Module) bool {
+	if ctx.ModuleType() != "cc_aconfig_library" {
+		return false
+	}
+
+	attrs := bazelCcAconfigLibraryAttributes{
+		SdkAttributes:        cc.Bp2BuildParseSdkAttributes(module),
+		Aconfig_declarations: *bazel.MakeLabelAttribute(android.BazelLabelForModuleDepSingle(ctx, this.properties.Aconfig_declarations).Label),
+		Dynamic_deps:         bazel.MakeLabelListAttribute(android.BazelLabelForModuleDeps(ctx, []string{baseLibDep})),
+	}
+	props := bazel.BazelTargetModuleProperties{
+		Rule_class:        "cc_aconfig_library",
+		Bzl_load_location: "//build/bazel/rules/cc:cc_aconfig_library.bzl",
+	}
+
+	ctx.CreateBazelTargetModule(
+		props,
+		android.CommonAttributes{
+			Name: ctx.ModuleName(),
+			Tags: android.ApexAvailableTagsWithoutTestApexes(ctx, module),
+		},
+		&attrs)
+	return true
+}
diff --git a/aconfig/codegen/cc_aconfig_library_test.go b/aconfig/codegen/cc_aconfig_library_test.go
new file mode 100644
index 0000000..0c8a969
--- /dev/null
+++ b/aconfig/codegen/cc_aconfig_library_test.go
@@ -0,0 +1,106 @@
+// Copyright 2023 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 codegen
+
+import (
+	"fmt"
+	"testing"
+
+	"android/soong/android"
+	"android/soong/cc"
+)
+
+var ccCodegenModeTestData = []struct {
+	setting, expected string
+}{
+	{"", "production"},
+	{"mode: `production`,", "production"},
+	{"mode: `test`,", "test"},
+	{"mode: `exported`,", "exported"},
+}
+
+func TestCCCodegenMode(t *testing.T) {
+	for _, testData := range ccCodegenModeTestData {
+		testCCCodegenModeHelper(t, testData.setting, testData.expected)
+	}
+}
+
+func testCCCodegenModeHelper(t *testing.T, bpMode string, ruleMode string) {
+	t.Helper()
+	result := android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		cc.PrepareForTestWithCcDefaultModules).
+		ExtendWithErrorHandler(android.FixtureExpectsNoErrors).
+		RunTestWithBp(t, fmt.Sprintf(`
+			aconfig_declarations {
+				name: "my_aconfig_declarations",
+				package: "com.example.package",
+				srcs: ["foo.aconfig"],
+			}
+
+			cc_library {
+    		name: "server_configurable_flags",
+    		srcs: ["server_configurable_flags.cc"],
+			}
+
+			cc_aconfig_library {
+				name: "my_cc_aconfig_library",
+				aconfig_declarations: "my_aconfig_declarations",
+				%s
+			}
+		`, bpMode))
+
+	module := result.ModuleForTests("my_cc_aconfig_library", "android_arm64_armv8-a_shared")
+	rule := module.Rule("cc_aconfig_library")
+	android.AssertStringEquals(t, "rule must contain test mode", rule.Args["mode"], ruleMode)
+}
+
+var incorrectCCCodegenModeTestData = []struct {
+	setting, expectedErr string
+}{
+	{"mode: `unsupported`,", "mode: \"unsupported\" is not a supported mode"},
+}
+
+func TestIncorrectCCCodegenMode(t *testing.T) {
+	for _, testData := range incorrectCCCodegenModeTestData {
+		testIncorrectCCCodegenModeHelper(t, testData.setting, testData.expectedErr)
+	}
+}
+
+func testIncorrectCCCodegenModeHelper(t *testing.T, bpMode string, err string) {
+	t.Helper()
+	android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		cc.PrepareForTestWithCcDefaultModules).
+		ExtendWithErrorHandler(android.FixtureExpectsOneErrorPattern(err)).
+		RunTestWithBp(t, fmt.Sprintf(`
+			aconfig_declarations {
+				name: "my_aconfig_declarations",
+				package: "com.example.package",
+				srcs: ["foo.aconfig"],
+			}
+
+			cc_library {
+    		name: "server_configurable_flags",
+    		srcs: ["server_configurable_flags.cc"],
+			}
+
+			cc_aconfig_library {
+				name: "my_cc_aconfig_library",
+				aconfig_declarations: "my_aconfig_declarations",
+				%s
+			}
+		`, bpMode))
+}
diff --git a/aconfig/codegen/init.go b/aconfig/codegen/init.go
new file mode 100644
index 0000000..0bff9d2
--- /dev/null
+++ b/aconfig/codegen/init.go
@@ -0,0 +1,83 @@
+// Copyright 2023 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 codegen
+
+import (
+	"android/soong/android"
+
+	"github.com/google/blueprint"
+)
+
+var (
+	pctx = android.NewPackageContext("android/soong/aconfig/codegen")
+
+	// For java_aconfig_library: Generate java library
+	javaRule = pctx.AndroidStaticRule("java_aconfig_library",
+		blueprint.RuleParams{
+			Command: `rm -rf ${out}.tmp` +
+				` && mkdir -p ${out}.tmp` +
+				` && ${aconfig} create-java-lib` +
+				`    --mode ${mode}` +
+				`    --cache ${in}` +
+				`    --out ${out}.tmp` +
+				` && $soong_zip -write_if_changed -jar -o ${out} -C ${out}.tmp -D ${out}.tmp` +
+				` && rm -rf ${out}.tmp`,
+			CommandDeps: []string{
+				"$aconfig",
+				"$soong_zip",
+			},
+			Restat: true,
+		}, "mode")
+
+	// For cc_aconfig_library: Generate C++ library
+	cppRule = pctx.AndroidStaticRule("cc_aconfig_library",
+		blueprint.RuleParams{
+			Command: `rm -rf ${gendir}` +
+				` && mkdir -p ${gendir}` +
+				` && ${aconfig} create-cpp-lib` +
+				`    --mode ${mode}` +
+				`    --cache ${in}` +
+				`    --out ${gendir}`,
+			CommandDeps: []string{
+				"$aconfig",
+			},
+		}, "gendir", "mode")
+
+	// For rust_aconfig_library: Generate Rust library
+	rustRule = pctx.AndroidStaticRule("rust_aconfig_library",
+		blueprint.RuleParams{
+			Command: `rm -rf ${gendir}` +
+				` && mkdir -p ${gendir}` +
+				` && ${aconfig} create-rust-lib` +
+				`    --mode ${mode}` +
+				`    --cache ${in}` +
+				`    --out ${gendir}`,
+			CommandDeps: []string{
+				"$aconfig",
+			},
+		}, "gendir", "mode")
+)
+
+func init() {
+	RegisterBuildComponents(android.InitRegistrationContext)
+	pctx.HostBinToolVariable("aconfig", "aconfig")
+	pctx.HostBinToolVariable("soong_zip", "soong_zip")
+}
+
+func RegisterBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("cc_aconfig_library", CcAconfigLibraryFactory)
+	ctx.RegisterModuleType("java_aconfig_library", JavaDeclarationsLibraryFactory)
+	ctx.RegisterModuleType("rust_aconfig_library", RustAconfigLibraryFactory)
+}
diff --git a/aconfig/codegen/java_aconfig_library.go b/aconfig/codegen/java_aconfig_library.go
new file mode 100644
index 0000000..e2fb15b
--- /dev/null
+++ b/aconfig/codegen/java_aconfig_library.go
@@ -0,0 +1,155 @@
+// Copyright 2023 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 codegen
+
+import (
+	"fmt"
+
+	"android/soong/aconfig"
+	"android/soong/android"
+	"android/soong/bazel"
+	"android/soong/java"
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
+)
+
+type declarationsTagType struct {
+	blueprint.BaseDependencyTag
+}
+
+var declarationsTag = declarationsTagType{}
+
+var aconfigSupportedModes = []string{"production", "test", "exported"}
+
+type JavaAconfigDeclarationsLibraryProperties struct {
+	// name of the aconfig_declarations module to generate a library for
+	Aconfig_declarations string
+
+	// default mode is "production", the other accepted modes are:
+	// "test": to generate test mode version of the library
+	// "exported": to generate exported mode version of the library
+	// an error will be thrown if the mode is not supported
+	Mode *string
+}
+
+type JavaAconfigDeclarationsLibraryCallbacks struct {
+	properties JavaAconfigDeclarationsLibraryProperties
+}
+
+func JavaDeclarationsLibraryFactory() android.Module {
+	callbacks := &JavaAconfigDeclarationsLibraryCallbacks{}
+	return java.GeneratedJavaLibraryModuleFactory("java_aconfig_library", callbacks, &callbacks.properties)
+}
+
+func (callbacks *JavaAconfigDeclarationsLibraryCallbacks) DepsMutator(module *java.GeneratedJavaLibraryModule, ctx android.BottomUpMutatorContext) {
+	declarations := callbacks.properties.Aconfig_declarations
+	if len(declarations) == 0 {
+		// TODO: Add test for this case
+		ctx.PropertyErrorf("aconfig_declarations", "aconfig_declarations property required")
+	} else {
+		ctx.AddDependency(ctx.Module(), declarationsTag, declarations)
+	}
+
+	// Add aconfig-annotations-lib as a dependency for the optimization / code stripping annotations
+	module.AddSharedLibrary("aconfig-annotations-lib")
+	// TODO(b/303773055): Remove the annotation after access issue is resolved.
+	module.AddSharedLibrary("unsupportedappusage")
+}
+
+func (callbacks *JavaAconfigDeclarationsLibraryCallbacks) GenerateSourceJarBuildActions(module *java.GeneratedJavaLibraryModule, ctx android.ModuleContext) android.Path {
+	// Get the values that came from the global RELEASE_ACONFIG_VALUE_SETS flag
+	declarationsModules := ctx.GetDirectDepsWithTag(declarationsTag)
+	if len(declarationsModules) != 1 {
+		panic(fmt.Errorf("Exactly one aconfig_declarations property required"))
+	}
+	declarations := ctx.OtherModuleProvider(declarationsModules[0], aconfig.DeclarationsProviderKey).(aconfig.DeclarationsProviderData)
+
+	// Generate the action to build the srcjar
+	srcJarPath := android.PathForModuleGen(ctx, ctx.ModuleName()+".srcjar")
+
+	mode := proptools.StringDefault(callbacks.properties.Mode, "production")
+	if !isModeSupported(mode) {
+		ctx.PropertyErrorf("mode", "%q is not a supported mode", mode)
+	}
+
+	ctx.Build(pctx, android.BuildParams{
+		Rule:        javaRule,
+		Input:       declarations.IntermediatePath,
+		Output:      srcJarPath,
+		Description: "aconfig.srcjar",
+		Args: map[string]string{
+			"mode": mode,
+		},
+	})
+
+	return srcJarPath
+}
+
+func isModeSupported(mode string) bool {
+	return android.InList(mode, aconfigSupportedModes)
+}
+
+type bazelJavaAconfigLibraryAttributes struct {
+	Aconfig_declarations bazel.LabelAttribute
+	Sdk_version          *string
+	Libs                 bazel.LabelListAttribute
+}
+
+func (callbacks *JavaAconfigDeclarationsLibraryCallbacks) Bp2build(ctx android.Bp2buildMutatorContext, module *java.GeneratedJavaLibraryModule) {
+	if ctx.ModuleType() != "java_aconfig_library" {
+		return
+	}
+
+	// By default, soong builds the aconfig java library with private_current, however
+	// bazel currently doesn't support it so we default it to system_current. One reason
+	// is that the dependency of all java_aconfig_library aconfig-annotations-lib is
+	// built with system_current. For the java aconfig library itself it doesn't really
+	// matter whether it uses private API or system API because the only module it uses
+	// is DeviceConfig which is in system, and the rdeps of the java aconfig library
+	// won't change its sdk version either, so this should be fine.
+	// Ideally we should only use the default value if it is not set by the user, but
+	// bazel only supports a limited sdk versions, for example, the java_aconfig_library
+	// modules in framework/base use core_platform which is not supported by bazel yet.
+	// TODO(b/302148527): change soong to default to system_current as well.
+	sdkVersion := "system_current"
+
+	var libs bazel.LabelListAttribute
+	archVariantProps := module.GetArchVariantProperties(ctx, &java.CommonProperties{})
+	for axis, configToProps := range archVariantProps {
+		for config, p := range configToProps {
+			if archProps, ok := p.(*java.CommonProperties); ok {
+				var libLabels []bazel.Label
+				for _, d := range archProps.Libs {
+					neverlinkLabel := android.BazelLabelForModuleDepSingle(ctx, d)
+					neverlinkLabel.Label = neverlinkLabel.Label + "-neverlink"
+					libLabels = append(libLabels, neverlinkLabel)
+				}
+				libs.SetSelectValue(axis, config, (bazel.MakeLabelList(libLabels)))
+			}
+		}
+	}
+
+	attrs := bazelJavaAconfigLibraryAttributes{
+		Aconfig_declarations: *bazel.MakeLabelAttribute(android.BazelLabelForModuleDepSingle(ctx, callbacks.properties.Aconfig_declarations).Label),
+		Sdk_version:          &sdkVersion,
+		Libs:                 libs,
+	}
+	props := bazel.BazelTargetModuleProperties{
+		Rule_class:        "java_aconfig_library",
+		Bzl_load_location: "//build/bazel/rules/java:java_aconfig_library.bzl",
+	}
+
+	ctx.CreateBazelTargetModule(props, android.CommonAttributes{Name: ctx.ModuleName()}, &attrs)
+}
diff --git a/aconfig/codegen/java_aconfig_library_test.go b/aconfig/codegen/java_aconfig_library_test.go
new file mode 100644
index 0000000..cbfdc21
--- /dev/null
+++ b/aconfig/codegen/java_aconfig_library_test.go
@@ -0,0 +1,233 @@
+// Copyright 2023 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 codegen
+
+import (
+	"fmt"
+	"testing"
+
+	"android/soong/android"
+	"android/soong/java"
+)
+
+// Note: These tests cover the code in the java package. It'd be ideal of that code could
+// be in the aconfig package.
+
+// With the bp parameter that defines a my_module, make sure it has the LOCAL_ACONFIG_FILES entries
+func runJavaAndroidMkTest(t *testing.T, bp string) {
+	result := android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		java.PrepareForTestWithJavaDefaultModules).
+		ExtendWithErrorHandler(android.FixtureExpectsNoErrors).
+		RunTestWithBp(t, bp+`
+			aconfig_declarations {
+				name: "my_aconfig_declarations_foo",
+				package: "com.example.package",
+				srcs: ["foo.aconfig"],
+			}
+
+			java_aconfig_library {
+				name: "my_java_aconfig_library_foo",
+				aconfig_declarations: "my_aconfig_declarations_foo",
+			}
+
+			aconfig_declarations {
+				name: "my_aconfig_declarations_bar",
+				package: "com.example.package",
+				srcs: ["bar.aconfig"],
+			}
+
+			java_aconfig_library {
+				name: "my_java_aconfig_library_bar",
+				aconfig_declarations: "my_aconfig_declarations_bar",
+			}
+		`)
+
+	module := result.ModuleForTests("my_module", "android_common").Module()
+
+	entry := android.AndroidMkEntriesForTest(t, result.TestContext, module)[0]
+
+	makeVar := entry.EntryMap["LOCAL_ACONFIG_FILES"]
+	android.AssertIntEquals(t, "len(LOCAL_ACONFIG_FILES)", 2, len(makeVar))
+	android.EnsureListContainsSuffix(t, makeVar, "my_aconfig_declarations_foo/intermediate.pb")
+	android.EnsureListContainsSuffix(t, makeVar, "my_aconfig_declarations_bar/intermediate.pb")
+}
+
+func TestAndroidMkJavaLibrary(t *testing.T) {
+	bp := `
+		java_library {
+			name: "my_module",
+			srcs: [
+				"src/foo.java",
+			],
+			static_libs: [
+				"my_java_aconfig_library_foo",
+				"my_java_aconfig_library_bar",
+			],
+			platform_apis: true,
+		}
+	`
+
+	runJavaAndroidMkTest(t, bp)
+}
+
+func TestAndroidMkAndroidApp(t *testing.T) {
+	bp := `
+		android_app {
+			name: "my_module",
+			srcs: [
+				"src/foo.java",
+			],
+			static_libs: [
+				"my_java_aconfig_library_foo",
+				"my_java_aconfig_library_bar",
+			],
+			platform_apis: true,
+		}
+	`
+
+	runJavaAndroidMkTest(t, bp)
+}
+
+func TestAndroidMkBinary(t *testing.T) {
+	bp := `
+		java_binary {
+			name: "my_module",
+			srcs: [
+				"src/foo.java",
+			],
+			static_libs: [
+				"my_java_aconfig_library_foo",
+				"my_java_aconfig_library_bar",
+			],
+			platform_apis: true,
+			main_class: "foo",
+		}
+	`
+
+	runJavaAndroidMkTest(t, bp)
+}
+
+func TestAndroidMkAndroidLibrary(t *testing.T) {
+	bp := `
+		android_library {
+			name: "my_module",
+			srcs: [
+				"src/foo.java",
+			],
+			static_libs: [
+				"my_java_aconfig_library_foo",
+				"my_java_aconfig_library_bar",
+			],
+			platform_apis: true,
+		}
+	`
+
+	runJavaAndroidMkTest(t, bp)
+}
+
+func TestAndroidMkBinaryThatLinksAgainstAar(t *testing.T) {
+	// Tests AndroidLibrary's propagation of flags through JavaInfo
+	bp := `
+		android_library {
+			name: "some_library",
+			srcs: [
+				"src/foo.java",
+			],
+			static_libs: [
+				"my_java_aconfig_library_foo",
+				"my_java_aconfig_library_bar",
+			],
+			platform_apis: true,
+		}
+		java_binary {
+			name: "my_module",
+			srcs: [
+				"src/bar.java",
+			],
+			static_libs: [
+				"some_library",
+			],
+			platform_apis: true,
+			main_class: "foo",
+		}
+	`
+
+	runJavaAndroidMkTest(t, bp)
+}
+
+func testCodegenMode(t *testing.T, bpMode string, ruleMode string) {
+	result := android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		java.PrepareForTestWithJavaDefaultModules).
+		ExtendWithErrorHandler(android.FixtureExpectsNoErrors).
+		RunTestWithBp(t, fmt.Sprintf(`
+			aconfig_declarations {
+				name: "my_aconfig_declarations",
+				package: "com.example.package",
+				srcs: ["foo.aconfig"],
+			}
+
+			java_aconfig_library {
+				name: "my_java_aconfig_library",
+				aconfig_declarations: "my_aconfig_declarations",
+				%s
+			}
+		`, bpMode))
+
+	module := result.ModuleForTests("my_java_aconfig_library", "android_common")
+	rule := module.Rule("java_aconfig_library")
+	android.AssertStringEquals(t, "rule must contain test mode", rule.Args["mode"], ruleMode)
+}
+
+func testCodegenModeWithError(t *testing.T, bpMode string, err string) {
+	android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		java.PrepareForTestWithJavaDefaultModules).
+		ExtendWithErrorHandler(android.FixtureExpectsOneErrorPattern(err)).
+		RunTestWithBp(t, fmt.Sprintf(`
+			aconfig_declarations {
+				name: "my_aconfig_declarations",
+				package: "com.example.package",
+				srcs: ["foo.aconfig"],
+			}
+
+			java_aconfig_library {
+				name: "my_java_aconfig_library",
+				aconfig_declarations: "my_aconfig_declarations",
+				%s
+			}
+		`, bpMode))
+}
+
+func TestDefaultProdMode(t *testing.T) {
+	testCodegenMode(t, "", "production")
+}
+
+func TestProdMode(t *testing.T) {
+	testCodegenMode(t, "mode: `production`,", "production")
+}
+
+func TestTestMode(t *testing.T) {
+	testCodegenMode(t, "mode: `test`,", "test")
+}
+
+func TestExportedMode(t *testing.T) {
+	testCodegenMode(t, "mode: `exported`,", "exported")
+}
+
+func TestUnsupportedMode(t *testing.T) {
+	testCodegenModeWithError(t, "mode: `unsupported`,", "mode: \"unsupported\" is not a supported mode")
+}
diff --git a/aconfig/codegen/rust_aconfig_library.go b/aconfig/codegen/rust_aconfig_library.go
new file mode 100644
index 0000000..3525de1
--- /dev/null
+++ b/aconfig/codegen/rust_aconfig_library.go
@@ -0,0 +1,97 @@
+package codegen
+
+import (
+	"fmt"
+
+	"android/soong/aconfig"
+	"android/soong/android"
+	"android/soong/rust"
+
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
+)
+
+type rustDeclarationsTagType struct {
+	blueprint.BaseDependencyTag
+}
+
+var rustDeclarationsTag = rustDeclarationsTagType{}
+
+type RustAconfigLibraryProperties struct {
+	// name of the aconfig_declarations module to generate a library for
+	Aconfig_declarations string
+
+	// default mode is "production", the other accepted modes are:
+	// "test": to generate test mode version of the library
+	// "exported": to generate exported mode version of the library
+	// an error will be thrown if the mode is not supported
+	Mode *string
+}
+
+type aconfigDecorator struct {
+	*rust.BaseSourceProvider
+
+	Properties RustAconfigLibraryProperties
+}
+
+func NewRustAconfigLibrary(hod android.HostOrDeviceSupported) (*rust.Module, *aconfigDecorator) {
+	aconfig := &aconfigDecorator{
+		BaseSourceProvider: rust.NewSourceProvider(),
+		Properties:         RustAconfigLibraryProperties{},
+	}
+
+	module := rust.NewSourceProviderModule(android.HostAndDeviceSupported, aconfig, false, false)
+	return module, aconfig
+}
+
+// rust_aconfig_library generates aconfig rust code from the provided aconfig declaration. This module type will
+// create library variants that can be used as a crate dependency by adding it to the rlibs, dylibs, and rustlibs
+// properties of other modules.
+func RustAconfigLibraryFactory() android.Module {
+	module, _ := NewRustAconfigLibrary(android.HostAndDeviceSupported)
+	return module.Init()
+}
+
+func (a *aconfigDecorator) SourceProviderProps() []interface{} {
+	return append(a.BaseSourceProvider.SourceProviderProps(), &a.Properties)
+}
+
+func (a *aconfigDecorator) GenerateSource(ctx rust.ModuleContext, deps rust.PathDeps) android.Path {
+	generatedDir := android.PathForModuleGen(ctx)
+	generatedSource := android.PathForModuleGen(ctx, "src", "lib.rs")
+
+	declarationsModules := ctx.GetDirectDepsWithTag(rustDeclarationsTag)
+
+	if len(declarationsModules) != 1 {
+		panic(fmt.Errorf("Exactly one aconfig_declarations property required"))
+	}
+	declarations := ctx.OtherModuleProvider(declarationsModules[0], aconfig.DeclarationsProviderKey).(aconfig.DeclarationsProviderData)
+
+	mode := proptools.StringDefault(a.Properties.Mode, "production")
+	if !isModeSupported(mode) {
+		ctx.PropertyErrorf("mode", "%q is not a supported mode", mode)
+	}
+
+	ctx.Build(pctx, android.BuildParams{
+		Rule:  rustRule,
+		Input: declarations.IntermediatePath,
+		Outputs: []android.WritablePath{
+			generatedSource,
+		},
+		Description: "rust_aconfig_library",
+		Args: map[string]string{
+			"gendir": generatedDir.String(),
+			"mode":   mode,
+		},
+	})
+	a.BaseSourceProvider.OutputFiles = android.Paths{generatedSource}
+	return generatedSource
+}
+
+func (a *aconfigDecorator) SourceProviderDeps(ctx rust.DepsContext, deps rust.Deps) rust.Deps {
+	deps = a.BaseSourceProvider.SourceProviderDeps(ctx, deps)
+	deps.Rustlibs = append(deps.Rustlibs, "libflags_rust")
+	deps.Rustlibs = append(deps.Rustlibs, "liblazy_static")
+	ctx.AddDependency(ctx.Module(), rustDeclarationsTag, a.Properties.Aconfig_declarations)
+	return deps
+}
diff --git a/aconfig/codegen/rust_aconfig_library_test.go b/aconfig/codegen/rust_aconfig_library_test.go
new file mode 100644
index 0000000..c09f701
--- /dev/null
+++ b/aconfig/codegen/rust_aconfig_library_test.go
@@ -0,0 +1,159 @@
+package codegen
+
+import (
+	"fmt"
+	"testing"
+
+	"android/soong/android"
+	"android/soong/rust"
+)
+
+func TestRustAconfigLibrary(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		rust.PrepareForTestWithRustIncludeVndk,
+		android.PrepareForTestWithArchMutator,
+		android.PrepareForTestWithDefaults,
+		android.PrepareForTestWithPrebuilts,
+	).
+		ExtendWithErrorHandler(android.FixtureExpectsNoErrors).
+		RunTestWithBp(t, fmt.Sprintf(`
+			rust_library {
+				name: "libflags_rust", // test mock
+				crate_name: "flags_rust",
+				srcs: ["lib.rs"],
+			}
+			rust_library {
+				name: "liblazy_static", // test mock
+				crate_name: "lazy_static",
+				srcs: ["src/lib.rs"],
+			}
+			aconfig_declarations {
+				name: "my_aconfig_declarations",
+				package: "com.example.package",
+				srcs: ["foo.aconfig"],
+			}
+
+			rust_aconfig_library {
+				name: "libmy_rust_aconfig_library",
+				crate_name: "my_rust_aconfig_library",
+				aconfig_declarations: "my_aconfig_declarations",
+			}
+		`))
+
+	sourceVariant := result.ModuleForTests("libmy_rust_aconfig_library", "android_arm64_armv8-a_source")
+	rule := sourceVariant.Rule("rust_aconfig_library")
+	android.AssertStringEquals(t, "rule must contain production mode", rule.Args["mode"], "production")
+
+	dylibVariant := result.ModuleForTests("libmy_rust_aconfig_library", "android_arm64_armv8-a_dylib")
+	rlibRlibStdVariant := result.ModuleForTests("libmy_rust_aconfig_library", "android_arm64_armv8-a_rlib_rlib-std")
+	rlibDylibStdVariant := result.ModuleForTests("libmy_rust_aconfig_library", "android_arm64_armv8-a_rlib_dylib-std")
+
+	variants := []android.TestingModule{
+		dylibVariant,
+		rlibDylibStdVariant,
+		rlibRlibStdVariant,
+	}
+
+	for _, variant := range variants {
+		android.AssertStringEquals(
+			t,
+			"dylib variant builds from generated rust code",
+			"out/soong/.intermediates/libmy_rust_aconfig_library/android_arm64_armv8-a_source/gen/src/lib.rs",
+			variant.Rule("rustc").Inputs[0].RelativeToTop().String(),
+		)
+	}
+}
+
+var rustCodegenModeTestData = []struct {
+	setting, expected string
+}{
+	{"", "production"},
+	{"mode: `production`,", "production"},
+	{"mode: `test`,", "test"},
+	{"mode: `exported`,", "exported"},
+}
+
+func TestRustCodegenMode(t *testing.T) {
+	for _, testData := range rustCodegenModeTestData {
+		testRustCodegenModeHelper(t, testData.setting, testData.expected)
+	}
+}
+
+func testRustCodegenModeHelper(t *testing.T, bpMode string, ruleMode string) {
+	t.Helper()
+	result := android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		rust.PrepareForTestWithRustIncludeVndk).
+		ExtendWithErrorHandler(android.FixtureExpectsNoErrors).
+		RunTestWithBp(t, fmt.Sprintf(`
+			rust_library {
+				name: "libflags_rust", // test mock
+				crate_name: "flags_rust",
+				srcs: ["lib.rs"],
+			}
+			rust_library {
+				name: "liblazy_static", // test mock
+				crate_name: "lazy_static",
+				srcs: ["src/lib.rs"],
+			}
+			aconfig_declarations {
+				name: "my_aconfig_declarations",
+				package: "com.example.package",
+				srcs: ["foo.aconfig"],
+			}
+			rust_aconfig_library {
+				name: "libmy_rust_aconfig_library",
+				crate_name: "my_rust_aconfig_library",
+				aconfig_declarations: "my_aconfig_declarations",
+				%s
+			}
+		`, bpMode))
+
+	module := result.ModuleForTests("libmy_rust_aconfig_library", "android_arm64_armv8-a_source")
+	rule := module.Rule("rust_aconfig_library")
+	android.AssertStringEquals(t, "rule must contain test mode", rule.Args["mode"], ruleMode)
+}
+
+var incorrectRustCodegenModeTestData = []struct {
+	setting, expectedErr string
+}{
+	{"mode: `unsupported`,", "mode: \"unsupported\" is not a supported mode"},
+}
+
+func TestIncorrectRustCodegenMode(t *testing.T) {
+	for _, testData := range incorrectRustCodegenModeTestData {
+		testIncorrectRustCodegenModeHelper(t, testData.setting, testData.expectedErr)
+	}
+}
+
+func testIncorrectRustCodegenModeHelper(t *testing.T, bpMode string, err string) {
+	t.Helper()
+	android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		rust.PrepareForTestWithRustIncludeVndk).
+		ExtendWithErrorHandler(android.FixtureExpectsOneErrorPattern(err)).
+		RunTestWithBp(t, fmt.Sprintf(`
+			rust_library {
+				name: "libflags_rust", // test mock
+				crate_name: "flags_rust",
+				srcs: ["lib.rs"],
+			}
+			rust_library {
+				name: "liblazy_static", // test mock
+				crate_name: "lazy_static",
+				srcs: ["src/lib.rs"],
+			}
+			aconfig_declarations {
+				name: "my_aconfig_declarations",
+				package: "com.example.package",
+				srcs: ["foo.aconfig"],
+			}
+			rust_aconfig_library {
+				name: "libmy_rust_aconfig_library",
+				crate_name: "my_rust_aconfig_library",
+				aconfig_declarations: "my_aconfig_declarations",
+				%s
+			}
+		`, bpMode))
+}
diff --git a/aconfig/codegen/testing.go b/aconfig/codegen/testing.go
new file mode 100644
index 0000000..3e1c22e
--- /dev/null
+++ b/aconfig/codegen/testing.go
@@ -0,0 +1,25 @@
+// Copyright (C) 2021 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 codegen
+
+import (
+	"android/soong/aconfig"
+	"android/soong/android"
+)
+
+var PrepareForTestWithAconfigBuildComponents = android.FixtureRegisterWithContext(func(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("aconfig_declarations", aconfig.DeclarationsFactory)
+	RegisterBuildComponents(ctx)
+})