diff --git a/bp2build/symlink_forest.go b/bp2build/symlink_forest.go
index 092b240..e2b99c4 100644
--- a/bp2build/symlink_forest.go
+++ b/bp2build/symlink_forest.go
@@ -21,7 +21,6 @@
 	"path/filepath"
 	"regexp"
 
-	"android/soong/android"
 	"android/soong/shared"
 )
 
@@ -31,14 +30,22 @@
 // or a directory. If excluded is true, then that file/directory should be
 // excluded from symlinking. Otherwise, the node is not excluded, but one of its
 // descendants is (otherwise the node in question would not exist)
-type node struct {
+
+type instructionsNode struct {
 	name     string
 	excluded bool // If false, this is just an intermediate node
-	children map[string]*node
+	children map[string]*instructionsNode
+}
+
+type symlinkForestContext struct {
+	verbose bool
+	topdir  string   // $TOPDIR
+	deps    []string // Files/directories read while constructing the forest
+	okay    bool     // Whether the forest was successfully  constructed
 }
 
 // Ensures that the node for the given path exists in the tree and returns it.
-func ensureNodeExists(root *node, path string) *node {
+func ensureNodeExists(root *instructionsNode, path string) *instructionsNode {
 	if path == "" {
 		return root
 	}
@@ -56,15 +63,14 @@
 	if child, ok := dn.children[base]; ok {
 		return child
 	} else {
-		dn.children[base] = &node{base, false, make(map[string]*node)}
+		dn.children[base] = &instructionsNode{base, false, make(map[string]*instructionsNode)}
 		return dn.children[base]
 	}
 }
 
-// Turns a list of paths to be excluded into a tree made of "node" objects where
-// the specified paths are marked as excluded.
-func treeFromExcludePathList(paths []string) *node {
-	result := &node{"", false, make(map[string]*node)}
+// Turns a list of paths to be excluded into a tree
+func instructionsFromExcludePathList(paths []string) *instructionsNode {
+	result := &instructionsNode{"", false, make(map[string]*instructionsNode)}
 
 	for _, p := range paths {
 		ensureNodeExists(result, p).excluded = true
@@ -179,17 +185,21 @@
 
 // Recursively plants a symlink forest at forestDir. The symlink tree will
 // contain every file in buildFilesDir and srcDir excluding the files in
-// exclude. Collects every directory encountered during the traversal of srcDir
-// into acc.
-func plantSymlinkForestRecursive(cfg android.Config, topdir string, forestDir string, buildFilesDir string, srcDir string, exclude *node, acc *[]string, okay *bool) {
-	if exclude != nil && exclude.excluded {
+// instructions. Collects every directory encountered during the traversal of
+// srcDir .
+func plantSymlinkForestRecursive(context *symlinkForestContext, instructions *instructionsNode, forestDir string, buildFilesDir string, srcDir string) {
+	if instructions != nil && instructions.excluded {
 		// This directory is not needed, bail out
 		return
 	}
 
-	*acc = append(*acc, srcDir)
-	srcDirMap := readdirToMap(shared.JoinPath(topdir, srcDir))
-	buildFilesMap := readdirToMap(shared.JoinPath(topdir, buildFilesDir))
+	// We don't add buildFilesDir here because the bp2build files marker files is
+	// already a dependency which covers it. If we ever wanted to turn this into
+	// a generic symlink forest creation tool, we'd need to add it, too.
+	context.deps = append(context.deps, srcDir)
+
+	srcDirMap := readdirToMap(shared.JoinPath(context.topdir, srcDir))
+	buildFilesMap := readdirToMap(shared.JoinPath(context.topdir, buildFilesDir))
 
 	renamingBuildFile := false
 	if _, ok := srcDirMap["BUILD"]; ok {
@@ -211,7 +221,7 @@
 		allEntries[n] = struct{}{}
 	}
 
-	err := os.MkdirAll(shared.JoinPath(topdir, forestDir), 0777)
+	err := os.MkdirAll(shared.JoinPath(context.topdir, forestDir), 0777)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Cannot mkdir '%s': %s\n", forestDir, err)
 		os.Exit(1)
@@ -230,69 +240,69 @@
 		}
 		buildFilesChild := shared.JoinPath(buildFilesDir, f)
 
-		// Descend in the exclusion tree, if there are any excludes left
-		var excludeChild *node = nil
-		if exclude != nil {
+		// Descend in the instruction tree if it exists
+		var instructionsChild *instructionsNode = nil
+		if instructions != nil {
 			if f == "BUILD.bazel" && renamingBuildFile {
-				excludeChild = exclude.children["BUILD"]
+				instructionsChild = instructions.children["BUILD"]
 			} else {
-				excludeChild = exclude.children[f]
+				instructionsChild = instructions.children[f]
 			}
 		}
 
 		srcChildEntry, sExists := srcDirMap[f]
 		buildFilesChildEntry, bExists := buildFilesMap[f]
 
-		if excludeChild != nil && excludeChild.excluded {
+		if instructionsChild != nil && instructionsChild.excluded {
 			if bExists {
-				symlinkIntoForest(topdir, forestChild, buildFilesChild)
+				symlinkIntoForest(context.topdir, forestChild, buildFilesChild)
 			}
 			continue
 		}
 
-		sDir := sExists && isDir(shared.JoinPath(topdir, srcChild), srcChildEntry)
-		bDir := bExists && isDir(shared.JoinPath(topdir, buildFilesChild), buildFilesChildEntry)
+		sDir := sExists && isDir(shared.JoinPath(context.topdir, srcChild), srcChildEntry)
+		bDir := bExists && isDir(shared.JoinPath(context.topdir, buildFilesChild), buildFilesChildEntry)
 
 		if !sExists {
-			if bDir && excludeChild != nil {
+			if bDir && instructionsChild != nil {
 				// Not in the source tree, but we have to exclude something from under
 				// this subtree, so descend
-				plantSymlinkForestRecursive(cfg, topdir, forestChild, buildFilesChild, srcChild, excludeChild, acc, okay)
+				plantSymlinkForestRecursive(context, instructionsChild, forestChild, buildFilesChild, srcChild)
 			} else {
 				// Not in the source tree, symlink BUILD file
-				symlinkIntoForest(topdir, forestChild, buildFilesChild)
+				symlinkIntoForest(context.topdir, forestChild, buildFilesChild)
 			}
 		} else if !bExists {
-			if sDir && excludeChild != nil {
+			if sDir && instructionsChild != nil {
 				// Not in the build file tree, but we have to exclude something from
 				// under this subtree, so descend
-				plantSymlinkForestRecursive(cfg, topdir, forestChild, buildFilesChild, srcChild, excludeChild, acc, okay)
+				plantSymlinkForestRecursive(context, instructionsChild, forestChild, buildFilesChild, srcChild)
 			} else {
 				// Not in the build file tree, symlink source tree, carry on
-				symlinkIntoForest(topdir, forestChild, srcChild)
+				symlinkIntoForest(context.topdir, forestChild, srcChild)
 			}
 		} else if sDir && bDir {
 			// Both are directories. Descend.
-			plantSymlinkForestRecursive(cfg, topdir, forestChild, buildFilesChild, srcChild, excludeChild, acc, okay)
+			plantSymlinkForestRecursive(context, instructionsChild, forestChild, buildFilesChild, srcChild)
 		} else if !sDir && !bDir {
 			// Neither is a directory. Merge them.
-			srcBuildFile := shared.JoinPath(topdir, srcChild)
-			generatedBuildFile := shared.JoinPath(topdir, buildFilesChild)
+			srcBuildFile := shared.JoinPath(context.topdir, srcChild)
+			generatedBuildFile := shared.JoinPath(context.topdir, buildFilesChild)
 			// The Android.bp file that codegen used to produce `buildFilesChild` is
 			// already a dependency, we can ignore `buildFilesChild`.
-			*acc = append(*acc, srcChild)
-			err = mergeBuildFiles(shared.JoinPath(topdir, forestChild), srcBuildFile, generatedBuildFile, cfg.IsEnvTrue("BP2BUILD_VERBOSE"))
+			context.deps = append(context.deps, srcChild)
+			err = mergeBuildFiles(shared.JoinPath(context.topdir, forestChild), srcBuildFile, generatedBuildFile, context.verbose)
 			if err != nil {
 				fmt.Fprintf(os.Stderr, "Error merging %s and %s: %s",
 					srcBuildFile, generatedBuildFile, err)
-				*okay = false
+				context.okay = false
 			}
 		} else {
 			// Both exist and one is a file. This is an error.
 			fmt.Fprintf(os.Stderr,
 				"Conflict in workspace symlink tree creation: both '%s' and '%s' exist and exactly one is a directory\n",
 				srcChild, buildFilesChild)
-			*okay = false
+			context.okay = false
 		}
 	}
 }
@@ -301,14 +311,20 @@
 // "srcDir" while excluding paths listed in "exclude". Returns the set of paths
 // under srcDir on which readdir() had to be called to produce the symlink
 // forest.
-func PlantSymlinkForest(cfg android.Config, topdir string, forest string, buildFiles string, srcDir string, exclude []string) []string {
-	deps := make([]string, 0)
+func PlantSymlinkForest(verbose bool, topdir string, forest string, buildFiles string, exclude []string) []string {
+	context := &symlinkForestContext{
+		verbose: verbose,
+		topdir:  topdir,
+		deps:    make([]string, 0),
+		okay:    true,
+	}
+
 	os.RemoveAll(shared.JoinPath(topdir, forest))
-	excludeTree := treeFromExcludePathList(exclude)
-	okay := true
-	plantSymlinkForestRecursive(cfg, topdir, forest, buildFiles, srcDir, excludeTree, &deps, &okay)
-	if !okay {
+
+	instructions := instructionsFromExcludePathList(exclude)
+	plantSymlinkForestRecursive(context, instructions, forest, buildFiles, ".")
+	if !context.okay {
 		os.Exit(1)
 	}
-	return deps
+	return context.deps
 }