Experimental code to support build action caching.

Bug: 335718784
Test: build locally
Change-Id: Icc1f1fb15f9fe305e95dd51e2e7aff1e9cbf340c

aconfig/aconfig_declarations.go

@@ -25,6 +25,7 @@ import (
 type DeclarationsModule struct {
 	android.ModuleBase
 	android.DefaultableModuleBase
+	blueprint.IncrementalModule
 
 	// Properties for "aconfig_declarations"
 	properties struct {
@@ -157,3 +158,17 @@ func (module *DeclarationsModule) GenerateAndroidBuildActions(ctx android.Module
 		IntermediateDumpOutputPath:  intermediateDumpFilePath,
 	})
 }
+
+func (module *DeclarationsModule) BuildActionProviderKeys() []blueprint.AnyProviderKey {
+	return []blueprint.AnyProviderKey{android.AconfigDeclarationsProviderKey}
+}
+
+func (module *DeclarationsModule) PackageContextPath() string {
+	return pkgPath
+}
+
+func (module *DeclarationsModule) CachedRules() []blueprint.Rule {
+	return []blueprint.Rule{aconfigRule, aconfigTextRule}
+}
+
+var _ blueprint.Incremental = &DeclarationsModule{}

aconfig/init.go

@@ -15,13 +15,16 @@
 package aconfig
 
 import (
+	"encoding/gob"
+
 	"android/soong/android"
 
 	"github.com/google/blueprint"
 )
 
 var (
-	pctx = android.NewPackageContext("android/soong/aconfig")
+	pkgPath = "android/soong/aconfig"
+	pctx    = android.NewPackageContext(pkgPath)
 
 	// For aconfig_declarations: Generate cache file
 	aconfigRule = pctx.AndroidStaticRule("aconfig",
@@ -106,6 +109,9 @@ func init() {
 	RegisterBuildComponents(android.InitRegistrationContext)
 	pctx.HostBinToolVariable("aconfig", "aconfig")
 	pctx.HostBinToolVariable("soong_zip", "soong_zip")
+
+	gob.Register(android.AconfigDeclarationsProviderData{})
+	gob.Register(android.ModuleOutPath{})
 }
 
 func RegisterBuildComponents(ctx android.RegistrationContext) {