2 files changed, 48 insertions, 21 deletions
diff --git a/android/logtags.go b/android/logtags.go
index 1e92dad68..abc37f997 100644
--- a/android/logtags.go
+++ b/android/logtags.go
@@ -14,10 +14,56 @@
 
 package android
 
-import "github.com/google/blueprint"
+import (
+	"strings"
+
+	"github.com/google/blueprint"
+)
+
+func init() {
+	RegisterParallelSingletonType("logtags", LogtagsSingleton)
+}
 
 type LogtagsInfo struct {
 	Logtags Paths
 }
 
 var LogtagsProviderKey = blueprint.NewProvider[*LogtagsInfo]()
+
+func LogtagsSingleton() Singleton {
+	return &logtagsSingleton{}
+}
+
+type logtagsSingleton struct{}
+
+func MergedLogtagsPath(ctx PathContext) OutputPath {
+	return PathForIntermediates(ctx, "all-event-log-tags.txt")
+}
+
+func (l *logtagsSingleton) GenerateBuildActions(ctx SingletonContext) {
+	var allLogtags Paths
+	ctx.VisitAllModules(func(module Module) {
+		if !module.ExportedToMake() {
+			return
+		}
+		if logtagsInfo, ok := OtherModuleProvider(ctx, module, LogtagsProviderKey); ok {
+			allLogtags = append(allLogtags, logtagsInfo.Logtags...)
+		}
+	})
+	allLogtags = SortedUniquePaths(allLogtags)
+	filteredLogTags := make([]Path, 0, len(allLogtags))
+	for _, p := range allLogtags {
+		// Logic copied from make:
+		// https://cs.android.com/android/platform/superproject/main/+/main:build/make/core/Makefile;l=987;drc=0585bb1bcf4c89065adaf709f48acc8b869fd3ce
+		if !strings.HasPrefix(p.String(), "vendor/") && !strings.HasPrefix(p.String(), "device/") && !strings.HasPrefix(p.String(), "out/") {
+			filteredLogTags = append(filteredLogTags, p)
+		}
+	}
+
+	builder := NewRuleBuilder(pctx, ctx)
+	builder.Command().
+		BuiltTool("merge-event-log-tags").
+		FlagWithOutput("-o ", MergedLogtagsPath(ctx)).
+		Inputs(filteredLogTags)
+	builder.Build("all-event-log-tags.txt", "merge logtags")
+}
diff --git a/filesystem/filesystem.go b/filesystem/filesystem.go
index b7a3adc8b..b30c0f77d 100644
--- a/filesystem/filesystem.go
+++ b/filesystem/filesystem.go
@@ -872,29 +872,10 @@ func (f *filesystem) buildEventLogtagsFile(ctx android.ModuleContext, builder *a
 		return
 	}
 
-	logtagsFilePaths := make(map[string]bool)
-	ctx.WalkDeps(func(child, parent android.Module) bool {
-		if logtagsInfo, ok := android.OtherModuleProvider(ctx, child, android.LogtagsProviderKey); ok {
-			for _, path := range logtagsInfo.Logtags {
-				logtagsFilePaths[path.String()] = true
-			}
-		}
-		return true
-	})
-
-	if len(logtagsFilePaths) == 0 {
-		return
-	}
-
 	etcPath := rebasedDir.Join(ctx, "etc")
 	eventLogtagsPath := etcPath.Join(ctx, "event-log-tags")
 	builder.Command().Text("mkdir").Flag("-p").Text(etcPath.String())
-	cmd := builder.Command().BuiltTool("merge-event-log-tags").
-		FlagWithArg("-o ", eventLogtagsPath.String())
-
-	for _, path := range android.SortedKeys(logtagsFilePaths) {
-		cmd.Text(path)
-	}
+	builder.Command().Text("cp").Input(android.MergedLogtagsPath(ctx)).Text(eventLogtagsPath.String())
 
 	f.appendToEntry(ctx, eventLogtagsPath)
 }