diff --git a/android/paths.go b/android/paths.go
index 56c3715f0..1202d6d47 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -94,7 +94,7 @@ type WritablePath interface {
 }
 
 type genPathProvider interface {
-	genPathWithExt(ctx ModuleContext, ext string) ModuleGenPath
+	genPathWithExt(ctx ModuleContext, subdir, ext string) ModuleGenPath
 }
 type objPathProvider interface {
 	objPathWithExt(ctx ModuleContext, subdir, ext string) ModuleObjPath
@@ -105,9 +105,9 @@ type resPathProvider interface {
 
 // GenPathWithExt derives a new file path in ctx's generated sources directory
 // from the current path, but with the new extension.
-func GenPathWithExt(ctx ModuleContext, p Path, ext string) ModuleGenPath {
+func GenPathWithExt(ctx ModuleContext, subdir string, p Path, ext string) ModuleGenPath {
 	if path, ok := p.(genPathProvider); ok {
-		return path.genPathWithExt(ctx, ext)
+		return path.genPathWithExt(ctx, subdir, ext)
 	}
 	reportPathError(ctx, "Tried to create generated file from unsupported path: %s(%s)", reflect.TypeOf(p).Name(), p)
 	return PathForModuleGen(ctx)
@@ -115,7 +115,7 @@ func GenPathWithExt(ctx ModuleContext, p Path, ext string) ModuleGenPath {
 
 // ObjPathWithExt derives a new file path in ctx's object directory from the
 // current path, but with the new extension.
-func ObjPathWithExt(ctx ModuleContext, p Path, subdir, ext string) ModuleObjPath {
+func ObjPathWithExt(ctx ModuleContext, subdir string, p Path, ext string) ModuleObjPath {
 	if path, ok := p.(objPathProvider); ok {
 		return path.objPathWithExt(ctx, subdir, ext)
 	}
@@ -535,8 +535,8 @@ func (p ModuleSrcPath) String() string {
 	return p.sourcePath.String()
 }
 
-func (p ModuleSrcPath) genPathWithExt(ctx ModuleContext, ext string) ModuleGenPath {
-	return PathForModuleGen(ctx, p.moduleDir, pathtools.ReplaceExtension(p.path, ext))
+func (p ModuleSrcPath) genPathWithExt(ctx ModuleContext, subdir, ext string) ModuleGenPath {
+	return PathForModuleGen(ctx, subdir, p.moduleDir, pathtools.ReplaceExtension(p.path, ext))
 }
 
 func (p ModuleSrcPath) objPathWithExt(ctx ModuleContext, subdir, ext string) ModuleObjPath {
@@ -583,9 +583,9 @@ func PathForModuleGen(ctx ModuleContext, paths ...string) ModuleGenPath {
 	}
 }
 
-func (p ModuleGenPath) genPathWithExt(ctx ModuleContext, ext string) ModuleGenPath {
+func (p ModuleGenPath) genPathWithExt(ctx ModuleContext, subdir, ext string) ModuleGenPath {
 	// TODO: make a different path for local vs remote generated files?
-	return PathForModuleGen(ctx, pathtools.ReplaceExtension(p.path, ext))
+	return PathForModuleGen(ctx, subdir, pathtools.ReplaceExtension(p.path, ext))
 }
 
 func (p ModuleGenPath) objPathWithExt(ctx ModuleContext, subdir, ext string) ModuleObjPath {
diff --git a/cc/builder.go b/cc/builder.go
index faa39d152..f795bba80 100644
--- a/cc/builder.go
+++ b/cc/builder.go
@@ -234,7 +234,7 @@ func TransformSourceToObj(ctx android.ModuleContext, subdir string, srcFiles and
 	}
 
 	for i, srcFile := range srcFiles {
-		objFile := android.ObjPathWithExt(ctx, srcFile, subdir, "o")
+		objFile := android.ObjPathWithExt(ctx, subdir, srcFile, "o")
 
 		objFiles[i] = objFile
 
@@ -285,7 +285,7 @@ func TransformSourceToObj(ctx android.ModuleContext, subdir string, srcFiles and
 		})
 
 		if tidy {
-			tidyFile := android.ObjPathWithExt(ctx, srcFile, subdir, "tidy")
+			tidyFile := android.ObjPathWithExt(ctx, subdir, srcFile, "tidy")
 			tidyFiles = append(tidyFiles, tidyFile)
 
 			ctx.ModuleBuild(pctx, android.ModuleBuildParams{
diff --git a/cc/gen.go b/cc/gen.go
index 145189562..9d3a67cf6 100644
--- a/cc/gen.go
+++ b/cc/gen.go
@@ -48,7 +48,7 @@ var (
 )
 
 func genYacc(ctx android.ModuleContext, yaccFile android.Path, outFile android.ModuleGenPath, yaccFlags string) (headerFile android.ModuleGenPath) {
-	headerFile = android.GenPathWithExt(ctx, yaccFile, "h")
+	headerFile = android.GenPathWithExt(ctx, "yacc", yaccFile, "h")
 
 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:    yacc,
@@ -80,19 +80,19 @@ func genSources(ctx android.ModuleContext, srcFiles android.Paths,
 	for i, srcFile := range srcFiles {
 		switch srcFile.Ext() {
 		case ".y":
-			cFile := android.GenPathWithExt(ctx, srcFile, "c")
+			cFile := android.GenPathWithExt(ctx, "yacc", srcFile, "c")
 			srcFiles[i] = cFile
 			deps = append(deps, genYacc(ctx, srcFile, cFile, buildFlags.yaccFlags))
 		case ".yy":
-			cppFile := android.GenPathWithExt(ctx, srcFile, "cpp")
+			cppFile := android.GenPathWithExt(ctx, "yacc", srcFile, "cpp")
 			srcFiles[i] = cppFile
 			deps = append(deps, genYacc(ctx, srcFile, cppFile, buildFlags.yaccFlags))
 		case ".l":
-			cFile := android.GenPathWithExt(ctx, srcFile, "c")
+			cFile := android.GenPathWithExt(ctx, "lex", srcFile, "c")
 			srcFiles[i] = cFile
 			genLex(ctx, srcFile, cFile)
 		case ".ll":
-			cppFile := android.GenPathWithExt(ctx, srcFile, "cpp")
+			cppFile := android.GenPathWithExt(ctx, "lex", srcFile, "cpp")
 			srcFiles[i] = cppFile
 			genLex(ctx, srcFile, cppFile)
 		case ".proto":
diff --git a/cc/proto.go b/cc/proto.go
index 3d3ca59f7..51f544898 100644
--- a/cc/proto.go
+++ b/cc/proto.go
@@ -15,8 +15,6 @@
 package cc
 
 import (
-	"strings"
-
 	"github.com/google/blueprint"
 
 	"android/soong/android"
@@ -46,17 +44,14 @@ var (
 func genProto(ctx android.ModuleContext, protoFile android.Path,
 	protoFlags string) (android.ModuleGenPath, android.ModuleGenPath) {
 
-	outDir := android.PathForModuleGen(ctx, "proto")
-	baseName := strings.TrimSuffix(protoFile.Base(), protoFile.Ext())
-
-	outFile := android.PathForModuleGen(ctx, "proto", ctx.ModuleDir(), baseName+".pb.cc")
-	headerFile := android.PathForModuleGen(ctx, "proto", ctx.ModuleDir(), baseName+".pb.h")
+	outFile := android.GenPathWithExt(ctx, "proto", protoFile, "pb.cc")
+	headerFile := android.GenPathWithExt(ctx, "proto", protoFile, "pb.h")
 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:    proto,
 		Outputs: android.WritablePaths{outFile, headerFile},
 		Input:   protoFile,
 		Args: map[string]string{
-			"outDir":     outDir.String(),
+			"outDir":     protoDir(ctx).String(),
 			"protoFlags": protoFlags,
 		},
 	})
diff --git a/genrule/genrule.go b/genrule/genrule.go
index f70c5fc33..5ee8b0bc2 100644
--- a/genrule/genrule.go
+++ b/genrule/genrule.go
@@ -196,7 +196,7 @@ func GenSrcsFactory() (blueprint.Module, []interface{}) {
 		for _, in := range srcFiles {
 			tasks = append(tasks, generateTask{
 				in:  android.Paths{in},
-				out: android.WritablePaths{android.GenPathWithExt(ctx, in, properties.Output_extension)},
+				out: android.WritablePaths{android.GenPathWithExt(ctx, "", in, properties.Output_extension)},
 			})
 		}
 		return tasks
diff --git a/java/gen.go b/java/gen.go
index 52a0c799d..062470854 100644
--- a/java/gen.go
+++ b/java/gen.go
@@ -57,7 +57,7 @@ var (
 )
 
 func genAidl(ctx android.ModuleContext, aidlFile android.Path, aidlFlags string) android.Path {
-	javaFile := android.GenPathWithExt(ctx, aidlFile, "java")
+	javaFile := android.GenPathWithExt(ctx, "aidl", aidlFile, "java")
 	depFile := javaFile.String() + ".d"
 
 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
@@ -74,7 +74,7 @@ func genAidl(ctx android.ModuleContext, aidlFile android.Path, aidlFlags string)
 }
 
 func genLogtags(ctx android.ModuleContext, logtagsFile android.Path) android.Path {
-	javaFile := android.GenPathWithExt(ctx, logtagsFile, "java")
+	javaFile := android.GenPathWithExt(ctx, "logtags", logtagsFile, "java")
 
 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:   logtags,