diff --git a/android/filegroup.go b/android/filegroup.go
index c2be22a..0b716c6 100644
--- a/android/filegroup.go
+++ b/android/filegroup.go
@@ -60,7 +60,11 @@
 }
 
 func (fg *fileGroup) GenerateAndroidBuildActions(ctx ModuleContext) {
-	fg.srcs = ctx.ExpandSourcesSubDir(fg.properties.Srcs, fg.properties.Exclude_srcs, String(fg.properties.Path))
+	fg.srcs = ctx.ExpandSources(fg.properties.Srcs, fg.properties.Exclude_srcs)
+
+	if fg.properties.Path != nil {
+		fg.srcs = PathsWithModuleSrcSubDir(ctx, fg.srcs, String(fg.properties.Path))
+	}
 }
 
 func (fg *fileGroup) Srcs() Paths {
diff --git a/android/module.go b/android/module.go
index 9a69a26..dfeb45d 100644
--- a/android/module.go
+++ b/android/module.go
@@ -117,7 +117,6 @@
 	ExpandSources(srcFiles, excludes []string) Paths
 	ExpandSource(srcFile, prop string) Path
 	ExpandOptionalSource(srcFile *string, prop string) OptionalPath
-	ExpandSourcesSubDir(srcFiles, excludes []string, subDir string) Paths
 	Glob(globPattern string, excludes []string) Paths
 	GlobFiles(globPattern string, excludes []string) Paths
 
@@ -1421,39 +1420,6 @@
 // Returns a list of paths expanded from globs and modules referenced using ":module" syntax.  The property must
 // be tagged with `android:"path" to support automatic source module dependency resolution.
 func (ctx *androidModuleContext) ExpandSources(srcFiles, excludes []string) Paths {
-	return ctx.ExpandSourcesSubDir(srcFiles, excludes, "")
-}
-
-// Returns a single path expanded from globs and modules referenced using ":module" syntax.  The property must
-// be tagged with `android:"path" to support automatic source module dependency resolution.
-func (ctx *androidModuleContext) ExpandSource(srcFile, prop string) Path {
-	srcFiles := ctx.ExpandSourcesSubDir([]string{srcFile}, nil, "")
-	if len(srcFiles) == 1 {
-		return srcFiles[0]
-	} else if len(srcFiles) == 0 {
-		if ctx.Config().AllowMissingDependencies() {
-			ctx.AddMissingDependencies([]string{srcFile})
-		} else {
-			ctx.PropertyErrorf(prop, "%s path %s does not exist", prop, srcFile)
-		}
-		return nil
-	} else {
-		ctx.PropertyErrorf(prop, "module providing %s must produce exactly one file", prop)
-		return nil
-	}
-}
-
-// Returns an optional single path expanded from globs and modules referenced using ":module" syntax if
-// the srcFile is non-nil.  The property must be tagged with `android:"path" to support automatic source module
-// dependency resolution.
-func (ctx *androidModuleContext) ExpandOptionalSource(srcFile *string, prop string) OptionalPath {
-	if srcFile != nil {
-		return OptionalPathForPath(ctx.ExpandSource(*srcFile, prop))
-	}
-	return OptionalPath{}
-}
-
-func (ctx *androidModuleContext) ExpandSourcesSubDir(srcFiles, excludes []string, subDir string) Paths {
 	prefix := PathForModuleSrc(ctx).String()
 
 	var expandedExcludes []string
@@ -1508,22 +1474,48 @@
 			}
 		} else if pathtools.IsGlob(s) {
 			globbedSrcFiles := ctx.GlobFiles(filepath.Join(prefix, s), expandedExcludes)
-			for i, s := range globbedSrcFiles {
-				globbedSrcFiles[i] = s.(ModuleSrcPath).WithSubDir(ctx, subDir)
-			}
+			globbedSrcFiles = PathsWithModuleSrcSubDir(ctx, globbedSrcFiles, "")
 			expandedSrcFiles = append(expandedSrcFiles, globbedSrcFiles...)
 		} else {
-			p := PathForModuleSrc(ctx, s).WithSubDir(ctx, subDir)
+			p := PathForModuleSrc(ctx, s)
 			j := findStringInSlice(p.String(), expandedExcludes)
 			if j == -1 {
 				expandedSrcFiles = append(expandedSrcFiles, p)
 			}
-
 		}
 	}
 	return expandedSrcFiles
 }
 
+// Returns a single path expanded from globs and modules referenced using ":module" syntax.  The property must
+// be tagged with `android:"path" to support automatic source module dependency resolution.
+func (ctx *androidModuleContext) ExpandSource(srcFile, prop string) Path {
+	srcFiles := ctx.ExpandSources([]string{srcFile}, nil)
+	if len(srcFiles) == 1 {
+		return srcFiles[0]
+	} else if len(srcFiles) == 0 {
+		if ctx.Config().AllowMissingDependencies() {
+			ctx.AddMissingDependencies([]string{srcFile})
+		} else {
+			ctx.PropertyErrorf(prop, "%s path %s does not exist", prop, srcFile)
+		}
+		return nil
+	} else {
+		ctx.PropertyErrorf(prop, "module providing %s must produce exactly one file", prop)
+		return nil
+	}
+}
+
+// Returns an optional single path expanded from globs and modules referenced using ":module" syntax if
+// the srcFile is non-nil.  The property must be tagged with `android:"path" to support automatic source module
+// dependency resolution.
+func (ctx *androidModuleContext) ExpandOptionalSource(srcFile *string, prop string) OptionalPath {
+	if srcFile != nil {
+		return OptionalPathForPath(ctx.ExpandSource(*srcFile, prop))
+	}
+	return OptionalPath{}
+}
+
 func (ctx *androidModuleContext) RequiredModuleNames() []string {
 	return ctx.module.base().commonProperties.Required
 }
diff --git a/android/paths.go b/android/paths.go
index afde55e..a0ea753 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -620,6 +620,15 @@
 	return p.withRel(path)
 }
 
+// join is like Join but does less path validation.
+func (p SourcePath) join(ctx PathContext, paths ...string) SourcePath {
+	path, err := validateSafePath(paths...)
+	if err != nil {
+		reportPathError(ctx, err)
+	}
+	return p.withRel(path)
+}
+
 // OverlayPath returns the overlay for `path' if it exists. This assumes that the
 // SourcePath is the path to a resource overlay directory.
 func (p SourcePath) OverlayPath(ctx ModuleContext, path Path) OptionalPath {
@@ -773,10 +782,30 @@
 	} else if !exists {
 		reportPathErrorf(ctx, "module source path %q does not exist", path)
 	}
-
 	return path
 }
 
+// PathsWithModuleSrcSubDir takes a list of Paths and returns a new list of Paths where Rel() on each path
+// will return the path relative to subDir in the module's source directory.  If any input paths are not located
+// inside subDir then a path error will be reported.
+func PathsWithModuleSrcSubDir(ctx ModuleContext, paths Paths, subDir string) Paths {
+	paths = append(Paths(nil), paths...)
+	subDirFullPath := PathForModuleSrc(ctx, subDir)
+	for i, path := range paths {
+		rel := Rel(ctx, subDirFullPath.String(), path.String())
+		paths[i] = subDirFullPath.join(ctx, rel)
+	}
+	return paths
+}
+
+// PathWithModuleSrcSubDir takes a Path and returns a Path where Rel() will return the path relative to subDir in the
+// module's source directory.  If the input path is not located inside subDir then a path error will be reported.
+func PathWithModuleSrcSubDir(ctx ModuleContext, path Path, subDir string) Path {
+	subDirFullPath := PathForModuleSrc(ctx, subDir)
+	rel := Rel(ctx, subDirFullPath.String(), path.String())
+	return subDirFullPath.Join(ctx, rel)
+}
+
 // OptionalPathForModuleSrc returns an OptionalPath. The OptionalPath contains a
 // valid path if p is non-nil.
 func OptionalPathForModuleSrc(ctx ModuleContext, p *string) OptionalPath {
@@ -799,12 +828,6 @@
 	return PathForModuleRes(ctx, p.path, name)
 }
 
-func (p ModuleSrcPath) WithSubDir(ctx ModuleContext, subdir string) ModuleSrcPath {
-	subdir = PathForModuleSrc(ctx, subdir).String()
-	p.rel = Rel(ctx, subdir, p.path)
-	return p
-}
-
 // ModuleOutPath is a Path representing a module's output directory.
 type ModuleOutPath struct {
 	OutputPath