check exported flags when building all_aconfig_declarations

This change adds extra step in the build of all_aconfig_declarations. It
will check whether all exported flags are valid. The exported flag is
valid if the flag is used for guarding API.

Test: m all_aconfig_declarations
Bug: 336800305
Change-Id: Ib1121e418f708b2ab290ed36aa3db7604cd04bdd

2 files changed, 42 insertions, 1 deletions

diff --git a/aconfig/all_aconfig_declarations.go b/aconfig/all_aconfig_declarations.go
index 3d07e16dc..31616d833 100644
--- a/aconfig/all_aconfig_declarations.go
+++ b/aconfig/all_aconfig_declarations.go
@@ -95,11 +95,44 @@ func GenerateFinalizedFlagsForApiSurface(ctx android.ModuleContext, outputPath a
 	})
 }
 
+func GenerateExportedFlagCheck(ctx android.ModuleContext, outputPath android.WritablePath,
+	parsedFlagsFile android.Path, apiSurface ApiSurfaceContributorProperties) {
+
+	apiSignatureFiles := android.Paths{}
+	for _, apiSignatureFile := range apiSurface.Api_signature_files.GetOrDefault(ctx, nil) {
+		if path := android.PathForModuleSrc(ctx, apiSignatureFile); path != nil {
+			apiSignatureFiles = append(apiSignatureFiles, path)
+		}
+	}
+	finalizedFlagsFile := android.PathForModuleSrc(ctx, apiSurface.Finalized_flags_file)
+
+	ctx.Build(pctx, android.BuildParams{
+		Rule:   ExportedFlagCheckRule,
+		Inputs: append(apiSignatureFiles, finalizedFlagsFile, parsedFlagsFile),
+		Output: outputPath,
+		Args: map[string]string{
+			"api_signature_files":  android.JoinPathsWithPrefix(apiSignatureFiles, "--api-signature-file "),
+			"finalized_flags_file": "--finalized-flags-file " + finalizedFlagsFile.String(),
+			"parsed_flags_file":    "--parsed-flags-file " + parsedFlagsFile.String(),
+		},
+	})
+}
+
 func (this *allAconfigDeclarationsSingleton) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	parsedFlagsFile := android.PathForIntermediates(ctx, "all_aconfig_declarations.pb")
 	this.finalizedFlags = android.PathForIntermediates(ctx, "finalized-flags.txt")
 	GenerateFinalizedFlagsForApiSurface(ctx, this.finalizedFlags, parsedFlagsFile, this.properties)
-	ctx.Phony("all_aconfig_declarations", this.finalizedFlags)
+
+	depsFiles := android.Paths{this.finalizedFlags}
+	if checkExportedFlag, ok := ctx.Config().GetBuildFlag("RELEASE_EXPORTED_FLAG_CHECK"); ok {
+		if checkExportedFlag == "true" {
+			invalidExportedFlags := android.PathForIntermediates(ctx, "invalid_exported_flags.txt")
+			GenerateExportedFlagCheck(ctx, invalidExportedFlags, parsedFlagsFile, this.properties)
+			depsFiles = append(depsFiles, invalidExportedFlags)
+		}
+	}
+
+	ctx.Phony("all_aconfig_declarations", depsFiles...)
 
 	android.SetProvider(ctx, allAconfigDeclarationsInfoProvider, allAconfigDeclarationsInfo{
 		parsedFlagsFile: parsedFlagsFile,
diff --git a/aconfig/init.go b/aconfig/init.go
index b2fe5a309..d8d547022 100644
--- a/aconfig/init.go
+++ b/aconfig/init.go
@@ -77,6 +77,13 @@ var (
 				"${record-finalized-flags}",
 			},
 		}, "api_signature_files", "finalized_flags_file", "parsed_flags_file")
+	ExportedFlagCheckRule = pctx.AndroidStaticRule("ExportedFlagCheckRule",
+		blueprint.RuleParams{
+			Command: `${exported-flag-check} ${parsed_flags_file} ${finalized_flags_file} ${api_signature_files} > ${out}`,
+			CommandDeps: []string{
+				"${exported-flag-check}",
+			},
+		}, "api_signature_files", "finalized_flags_file", "parsed_flags_file")
 
 	CreateStorageRule = pctx.AndroidStaticRule("aconfig_create_storage",
 		blueprint.RuleParams{
@@ -124,6 +131,7 @@ func init() {
 	pctx.HostBinToolVariable("aconfig", "aconfig")
 	pctx.HostBinToolVariable("soong_zip", "soong_zip")
 	pctx.HostBinToolVariable("record-finalized-flags", "record-finalized-flags")
+	pctx.HostBinToolVariable("exported-flag-check", "exported-flag-check")
 }
 
 func RegisterBuildComponents(ctx android.RegistrationContext) {