diff --git a/android/Android.bp b/android/Android.bp
index 4bd272d..f8c1d55 100644
--- a/android/Android.bp
+++ b/android/Android.bp
@@ -23,7 +23,8 @@
         "csuite_config.go",
         "defaults.go",
         "defs.go",
-        "depset.go",
+        "depset_generic.go",
+        "depset_paths.go",
         "deptag.go",
         "expand.go",
         "filegroup.go",
diff --git a/android/depset.go b/android/depset.go
deleted file mode 100644
index 60ebcac..0000000
--- a/android/depset.go
+++ /dev/null
@@ -1,194 +0,0 @@
-// Copyright 2020 Google Inc. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package android
-
-import "fmt"
-
-// DepSet is designed to be conceptually compatible with Bazel's depsets:
-// https://docs.bazel.build/versions/master/skylark/depsets.html
-
-// A DepSet efficiently stores Paths from transitive dependencies without copying. It is stored
-// as a DAG of DepSet nodes, each of which has some direct contents and a list of dependency
-// DepSet nodes.
-//
-// A DepSet has an order that will be used to walk the DAG when ToList() is called.  The order
-// can be POSTORDER, PREORDER, or TOPOLOGICAL.  POSTORDER and PREORDER orders return a postordered
-// or preordered left to right flattened list.  TOPOLOGICAL returns a list that guarantees that
-// elements of children are listed after all of their parents (unless there are duplicate direct
-// elements in the DepSet or any of its transitive dependencies, in which case the ordering of the
-// duplicated element is not guaranteed).
-//
-// A DepSet is created by NewDepSet or NewDepSetBuilder.Build from the Paths for direct contents
-// and the *DepSets of dependencies. A DepSet is immutable once created.
-type DepSet struct {
-	preorder   bool
-	reverse    bool
-	order      DepSetOrder
-	direct     Paths
-	transitive []*DepSet
-}
-
-// DepSetBuilder is used to create an immutable DepSet.
-type DepSetBuilder struct {
-	order      DepSetOrder
-	direct     Paths
-	transitive []*DepSet
-}
-
-type DepSetOrder int
-
-const (
-	PREORDER DepSetOrder = iota
-	POSTORDER
-	TOPOLOGICAL
-)
-
-func (o DepSetOrder) String() string {
-	switch o {
-	case PREORDER:
-		return "PREORDER"
-	case POSTORDER:
-		return "POSTORDER"
-	case TOPOLOGICAL:
-		return "TOPOLOGICAL"
-	default:
-		panic(fmt.Errorf("Invalid DepSetOrder %d", o))
-	}
-}
-
-// NewDepSet returns an immutable DepSet with the given order, direct and transitive contents.
-func NewDepSet(order DepSetOrder, direct Paths, transitive []*DepSet) *DepSet {
-	var directCopy Paths
-	transitiveCopy := make([]*DepSet, 0, len(transitive))
-
-	for _, dep := range transitive {
-		if dep != nil {
-			if dep.order != order {
-				panic(fmt.Errorf("incompatible order, new DepSet is %s but transitive DepSet is %s",
-					order, dep.order))
-			}
-			transitiveCopy = append(transitiveCopy, dep)
-		}
-	}
-
-	if order == TOPOLOGICAL {
-		directCopy = ReversePaths(direct)
-		reverseDepSetsInPlace(transitiveCopy)
-	} else {
-		// Use copy instead of append(nil, ...) to make a slice that is exactly the size of the input
-		// slice.  The DepSet is immutable, there is no need for additional capacity.
-		directCopy = make(Paths, len(direct))
-		copy(directCopy, direct)
-	}
-
-	return &DepSet{
-		preorder:   order == PREORDER,
-		reverse:    order == TOPOLOGICAL,
-		order:      order,
-		direct:     directCopy,
-		transitive: transitiveCopy,
-	}
-}
-
-// NewDepSetBuilder returns a DepSetBuilder to create an immutable DepSet with the given order.
-func NewDepSetBuilder(order DepSetOrder) *DepSetBuilder {
-	return &DepSetBuilder{order: order}
-}
-
-// Direct adds direct contents to the DepSet being built by a DepSetBuilder. Newly added direct
-// contents are to the right of any existing direct contents.
-func (b *DepSetBuilder) Direct(direct ...Path) *DepSetBuilder {
-	b.direct = append(b.direct, direct...)
-	return b
-}
-
-// Transitive adds transitive contents to the DepSet being built by a DepSetBuilder. Newly added
-// transitive contents are to the right of any existing transitive contents.
-func (b *DepSetBuilder) Transitive(transitive ...*DepSet) *DepSetBuilder {
-	b.transitive = append(b.transitive, transitive...)
-	return b
-}
-
-// Returns the DepSet being built by this DepSetBuilder.  The DepSetBuilder retains its contents
-// for creating more DepSets.
-func (b *DepSetBuilder) Build() *DepSet {
-	return NewDepSet(b.order, b.direct, b.transitive)
-}
-
-// walk calls the visit method in depth-first order on a DepSet, preordered if d.preorder is set,
-// otherwise postordered.
-func (d *DepSet) walk(visit func(Paths)) {
-	visited := make(map[*DepSet]bool)
-
-	var dfs func(d *DepSet)
-	dfs = func(d *DepSet) {
-		visited[d] = true
-		if d.preorder {
-			visit(d.direct)
-		}
-		for _, dep := range d.transitive {
-			if !visited[dep] {
-				dfs(dep)
-			}
-		}
-
-		if !d.preorder {
-			visit(d.direct)
-		}
-	}
-
-	dfs(d)
-}
-
-// ToList returns the DepSet flattened to a list.  The order in the list is based on the order
-// of the DepSet.  POSTORDER and PREORDER orders return a postordered or preordered left to right
-// flattened list.  TOPOLOGICAL returns a list that guarantees that elements of children are listed
-// after all of their parents (unless there are duplicate direct elements in the DepSet or any of
-// its transitive dependencies, in which case the ordering of the duplicated element is not
-// guaranteed).
-func (d *DepSet) ToList() Paths {
-	if d == nil {
-		return nil
-	}
-	var list Paths
-	d.walk(func(paths Paths) {
-		list = append(list, paths...)
-	})
-	list = FirstUniquePaths(list)
-	if d.reverse {
-		reversePathsInPlace(list)
-	}
-	return list
-}
-
-// ToSortedList returns the direct and transitive contents of a DepSet in lexically sorted order
-// with duplicates removed.
-func (d *DepSet) ToSortedList() Paths {
-	list := d.ToList()
-	return SortedUniquePaths(list)
-}
-
-func reversePathsInPlace(list Paths) {
-	for i, j := 0, len(list)-1; i < j; i, j = i+1, j-1 {
-		list[i], list[j] = list[j], list[i]
-	}
-}
-
-func reverseDepSetsInPlace(list []*DepSet) {
-	for i, j := 0, len(list)-1; i < j; i, j = i+1, j-1 {
-		list[i], list[j] = list[j], list[i]
-	}
-
-}
diff --git a/android/depset_generic.go b/android/depset_generic.go
new file mode 100644
index 0000000..f00e462
--- /dev/null
+++ b/android/depset_generic.go
@@ -0,0 +1,351 @@
+// Copyright 2020 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// depSet is designed to be conceptually compatible with Bazel's depsets:
+// https://docs.bazel.build/versions/master/skylark/depsets.html
+
+type DepSetOrder int
+
+const (
+	PREORDER DepSetOrder = iota
+	POSTORDER
+	TOPOLOGICAL
+)
+
+func (o DepSetOrder) String() string {
+	switch o {
+	case PREORDER:
+		return "PREORDER"
+	case POSTORDER:
+		return "POSTORDER"
+	case TOPOLOGICAL:
+		return "TOPOLOGICAL"
+	default:
+		panic(fmt.Errorf("Invalid DepSetOrder %d", o))
+	}
+}
+
+// A depSet efficiently stores a slice of an arbitrary type from transitive dependencies without
+// copying. It is stored as a DAG of depSet nodes, each of which has some direct contents and a list
+// of dependency depSet nodes.
+//
+// A depSet has an order that will be used to walk the DAG when ToList() is called.  The order
+// can be POSTORDER, PREORDER, or TOPOLOGICAL.  POSTORDER and PREORDER orders return a postordered
+// or preordered left to right flattened list.  TOPOLOGICAL returns a list that guarantees that
+// elements of children are listed after all of their parents (unless there are duplicate direct
+// elements in the depSet or any of its transitive dependencies, in which case the ordering of the
+// duplicated element is not guaranteed).
+//
+// A depSet is created by newDepSet or newDepSetBuilder.Build from the slice for direct contents
+// and the *depSets of dependencies. A depSet is immutable once created.
+//
+// This object uses reflection to remain agnostic to the type it contains.  It should be replaced
+// with generics once those exist in Go.  Callers should generally use a thin wrapper around depSet
+// that provides type-safe methods like DepSet for Paths.
+type depSet struct {
+	preorder   bool
+	reverse    bool
+	order      DepSetOrder
+	direct     interface{}
+	transitive []*depSet
+}
+
+type depSetInterface interface {
+	embeddedDepSet() *depSet
+}
+
+func (d *depSet) embeddedDepSet() *depSet {
+	return d
+}
+
+var _ depSetInterface = (*depSet)(nil)
+
+// newDepSet returns an immutable depSet with the given order, direct and transitive contents.
+// direct must be a slice, but is not type-safe due to the lack of generics in Go.  It can be a
+// nil slice, but not a nil interface{}, i.e. []string(nil) but not nil.
+func newDepSet(order DepSetOrder, direct interface{}, transitive interface{}) *depSet {
+	var directCopy interface{}
+	transitiveDepSet := sliceToDepSets(transitive, order)
+
+	if order == TOPOLOGICAL {
+		directCopy = reverseSlice(direct)
+		reverseSliceInPlace(transitiveDepSet)
+	} else {
+		directCopy = copySlice(direct)
+	}
+
+	return &depSet{
+		preorder:   order == PREORDER,
+		reverse:    order == TOPOLOGICAL,
+		order:      order,
+		direct:     directCopy,
+		transitive: transitiveDepSet,
+	}
+}
+
+// depSetBuilder is used to create an immutable depSet.
+type depSetBuilder struct {
+	order      DepSetOrder
+	direct     reflect.Value
+	transitive []*depSet
+}
+
+// newDepSetBuilder returns a depSetBuilder to create an immutable depSet with the given order and
+// type, represented by a slice of type that will be in the depSet.
+func newDepSetBuilder(order DepSetOrder, typ interface{}) *depSetBuilder {
+	empty := reflect.Zero(reflect.TypeOf(typ))
+	return &depSetBuilder{
+		order:  order,
+		direct: empty,
+	}
+}
+
+// sliceToDepSets converts a slice of any type that implements depSetInterface (by having a depSet
+// embedded in it) into a []*depSet.
+func sliceToDepSets(in interface{}, order DepSetOrder) []*depSet {
+	slice := reflect.ValueOf(in)
+	length := slice.Len()
+	out := make([]*depSet, length)
+	for i := 0; i < length; i++ {
+		vi := slice.Index(i)
+		depSetIntf, ok := vi.Interface().(depSetInterface)
+		if !ok {
+			panic(fmt.Errorf("element %d is a %s, not a depSetInterface", i, vi.Type()))
+		}
+		depSet := depSetIntf.embeddedDepSet()
+		if depSet.order != order {
+			panic(fmt.Errorf("incompatible order, new depSet is %s but transitive depSet is %s",
+				order, depSet.order))
+		}
+		out[i] = depSet
+	}
+	return out
+}
+
+// DirectSlice adds direct contents to the depSet being built by a depSetBuilder. Newly added direct
+// contents are to the right of any existing direct contents.  The argument must be a slice, but
+// is not type-safe due to the lack of generics in Go.
+func (b *depSetBuilder) DirectSlice(direct interface{}) *depSetBuilder {
+	b.direct = reflect.AppendSlice(b.direct, reflect.ValueOf(direct))
+	return b
+}
+
+// Direct adds direct contents to the depSet being built by a depSetBuilder. Newly added direct
+// contents are to the right of any existing direct contents.  The argument must be the same type
+// as the element of the slice passed to newDepSetBuilder, but is not type-safe due to the lack of
+// generics in Go.
+func (b *depSetBuilder) Direct(direct interface{}) *depSetBuilder {
+	b.direct = reflect.Append(b.direct, reflect.ValueOf(direct))
+	return b
+}
+
+// Transitive adds transitive contents to the DepSet being built by a DepSetBuilder. Newly added
+// transitive contents are to the right of any existing transitive contents.  The argument can
+// be any slice of type that has depSet embedded in it.
+func (b *depSetBuilder) Transitive(transitive interface{}) *depSetBuilder {
+	depSets := sliceToDepSets(transitive, b.order)
+	b.transitive = append(b.transitive, depSets...)
+	return b
+}
+
+// Returns the depSet being built by this depSetBuilder.  The depSetBuilder retains its contents
+// for creating more depSets.
+func (b *depSetBuilder) Build() *depSet {
+	return newDepSet(b.order, b.direct.Interface(), b.transitive)
+}
+
+// walk calls the visit method in depth-first order on a DepSet, preordered if d.preorder is set,
+// otherwise postordered.
+func (d *depSet) walk(visit func(interface{})) {
+	visited := make(map[*depSet]bool)
+
+	var dfs func(d *depSet)
+	dfs = func(d *depSet) {
+		visited[d] = true
+		if d.preorder {
+			visit(d.direct)
+		}
+		for _, dep := range d.transitive {
+			if !visited[dep] {
+				dfs(dep)
+			}
+		}
+
+		if !d.preorder {
+			visit(d.direct)
+		}
+	}
+
+	dfs(d)
+}
+
+// ToList returns the depSet flattened to a list.  The order in the list is based on the order
+// of the depSet.  POSTORDER and PREORDER orders return a postordered or preordered left to right
+// flattened list.  TOPOLOGICAL returns a list that guarantees that elements of children are listed
+// after all of their parents (unless there are duplicate direct elements in the DepSet or any of
+// its transitive dependencies, in which case the ordering of the duplicated element is not
+// guaranteed).
+//
+// This method uses a reflection-based implementation to find the unique elements in slice, which
+// is around 3x slower than a concrete implementation.  Type-safe wrappers around depSet can
+// provide their own implementation of ToList that calls depSet.toList with a method that
+// uses a concrete implementation.
+func (d *depSet) ToList() interface{} {
+	return d.toList(firstUnique)
+}
+
+// toList returns the depSet flattened to a list.  The order in the list is based on the order
+// of the depSet.  POSTORDER and PREORDER orders return a postordered or preordered left to right
+// flattened list.  TOPOLOGICAL returns a list that guarantees that elements of children are listed
+// after all of their parents (unless there are duplicate direct elements in the DepSet or any of
+// its transitive dependencies, in which case the ordering of the duplicated element is not
+// guaranteed).  The firstUniqueFunc is used to remove duplicates from the list.
+func (d *depSet) toList(firstUniqueFunc func(interface{}) interface{}) interface{} {
+	if d == nil {
+		return nil
+	}
+	slice := reflect.Zero(reflect.TypeOf(d.direct))
+	d.walk(func(paths interface{}) {
+		slice = reflect.AppendSlice(slice, reflect.ValueOf(paths))
+	})
+	list := slice.Interface()
+	list = firstUniqueFunc(list)
+	if d.reverse {
+		reverseSliceInPlace(list)
+	}
+	return list
+}
+
+// firstUnique returns all unique elements of a slice, keeping the first copy of each.  It
+// modifies the slice contents in place, and returns a subslice of the original slice.  The
+// argument must be a slice, but is not type-safe due to the lack of reflection in Go.
+//
+// Performance of the reflection-based firstUnique is up to 3x slower than a concrete type
+// version such as FirstUniqueStrings.
+func firstUnique(slice interface{}) interface{} {
+	// 4 was chosen based on Benchmark_firstUnique results.
+	if reflect.ValueOf(slice).Len() > 4 {
+		return firstUniqueMap(slice)
+	}
+	return firstUniqueList(slice)
+}
+
+// firstUniqueList is an implementation of firstUnique using an O(N^2) list comparison to look for
+// duplicates.
+func firstUniqueList(in interface{}) interface{} {
+	writeIndex := 0
+	slice := reflect.ValueOf(in)
+	length := slice.Len()
+outer:
+	for readIndex := 0; readIndex < length; readIndex++ {
+		readValue := slice.Index(readIndex)
+		for compareIndex := 0; compareIndex < writeIndex; compareIndex++ {
+			compareValue := slice.Index(compareIndex)
+			// These two Interface() calls seem to cause an allocation and significantly
+			// slow down this list-based implementation.  The map implementation below doesn't
+			// have this issue because reflect.Value.MapIndex takes a Value and appears to be
+			// able to do the map lookup without an allocation.
+			if readValue.Interface() == compareValue.Interface() {
+				// The value at readIndex already exists somewhere in the output region
+				// of the slice before writeIndex, skip it.
+				continue outer
+			}
+		}
+		if readIndex != writeIndex {
+			writeValue := slice.Index(writeIndex)
+			writeValue.Set(readValue)
+		}
+		writeIndex++
+	}
+	return slice.Slice(0, writeIndex).Interface()
+}
+
+var trueValue = reflect.ValueOf(true)
+
+// firstUniqueList is an implementation of firstUnique using an O(N) hash set lookup to look for
+// duplicates.
+func firstUniqueMap(in interface{}) interface{} {
+	writeIndex := 0
+	slice := reflect.ValueOf(in)
+	length := slice.Len()
+	seen := reflect.MakeMapWithSize(reflect.MapOf(slice.Type().Elem(), trueValue.Type()), slice.Len())
+	for readIndex := 0; readIndex < length; readIndex++ {
+		readValue := slice.Index(readIndex)
+		if seen.MapIndex(readValue).IsValid() {
+			continue
+		}
+		seen.SetMapIndex(readValue, trueValue)
+		if readIndex != writeIndex {
+			writeValue := slice.Index(writeIndex)
+			writeValue.Set(readValue)
+		}
+		writeIndex++
+	}
+	return slice.Slice(0, writeIndex).Interface()
+}
+
+// reverseSliceInPlace reverses the elements of a slice in place.  The argument must be a slice, but
+// is not type-safe due to the lack of reflection in Go.
+func reverseSliceInPlace(in interface{}) {
+	swapper := reflect.Swapper(in)
+	slice := reflect.ValueOf(in)
+	length := slice.Len()
+	for i, j := 0, length-1; i < j; i, j = i+1, j-1 {
+		swapper(i, j)
+	}
+}
+
+// reverseSlice returns a copy of a slice in reverse order.  The argument must be a slice, but is
+// not type-safe due to the lack of reflection in Go.
+func reverseSlice(in interface{}) interface{} {
+	slice := reflect.ValueOf(in)
+	if !slice.IsValid() || slice.IsNil() {
+		return in
+	}
+	if slice.Kind() != reflect.Slice {
+		panic(fmt.Errorf("%t is not a slice", in))
+	}
+	length := slice.Len()
+	if length == 0 {
+		return in
+	}
+	out := reflect.MakeSlice(slice.Type(), length, length)
+	for i := 0; i < length; i++ {
+		out.Index(i).Set(slice.Index(length - 1 - i))
+	}
+	return out.Interface()
+}
+
+// copySlice returns a copy of a slice.  The argument must be a slice, but is not type-safe due to
+// the lack of reflection in Go.
+func copySlice(in interface{}) interface{} {
+	slice := reflect.ValueOf(in)
+	if !slice.IsValid() || slice.IsNil() {
+		return in
+	}
+	length := slice.Len()
+	if length == 0 {
+		return in
+	}
+	out := reflect.MakeSlice(slice.Type(), length, length)
+	reflect.Copy(out, slice)
+	return out.Interface()
+}
diff --git a/android/depset_paths.go b/android/depset_paths.go
new file mode 100644
index 0000000..ed561ba
--- /dev/null
+++ b/android/depset_paths.go
@@ -0,0 +1,94 @@
+// Copyright 2020 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+// This file implements DepSet, a thin type-safe wrapper around depSet that contains Paths.
+
+// A DepSet efficiently stores Paths from transitive dependencies without copying. It is stored
+// as a DAG of DepSet nodes, each of which has some direct contents and a list of dependency
+// DepSet nodes.
+//
+// A DepSet has an order that will be used to walk the DAG when ToList() is called.  The order
+// can be POSTORDER, PREORDER, or TOPOLOGICAL.  POSTORDER and PREORDER orders return a postordered
+// or preordered left to right flattened list.  TOPOLOGICAL returns a list that guarantees that
+// elements of children are listed after all of their parents (unless there are duplicate direct
+// elements in the DepSet or any of its transitive dependencies, in which case the ordering of the
+// duplicated element is not guaranteed).
+//
+// A DepSet is created by NewDepSet or NewDepSetBuilder.Build from the Paths for direct contents
+// and the *DepSets of dependencies. A DepSet is immutable once created.
+type DepSet struct {
+	depSet
+}
+
+// DepSetBuilder is used to create an immutable DepSet.
+type DepSetBuilder struct {
+	depSetBuilder
+}
+
+// NewDepSet returns an immutable DepSet with the given order, direct and transitive contents.
+func NewDepSet(order DepSetOrder, direct Paths, transitive []*DepSet) *DepSet {
+	return &DepSet{*newDepSet(order, direct, transitive)}
+}
+
+// NewDepSetBuilder returns a DepSetBuilder to create an immutable DepSet with the given order.
+func NewDepSetBuilder(order DepSetOrder) *DepSetBuilder {
+	return &DepSetBuilder{*newDepSetBuilder(order, Paths(nil))}
+}
+
+// Direct adds direct contents to the DepSet being built by a DepSetBuilder. Newly added direct
+// contents are to the right of any existing direct contents.
+func (b *DepSetBuilder) Direct(direct ...Path) *DepSetBuilder {
+	b.depSetBuilder.DirectSlice(direct)
+	return b
+}
+
+// Transitive adds transitive contents to the DepSet being built by a DepSetBuilder. Newly added
+// transitive contents are to the right of any existing transitive contents.
+func (b *DepSetBuilder) Transitive(transitive ...*DepSet) *DepSetBuilder {
+	b.depSetBuilder.Transitive(transitive)
+	return b
+}
+
+// Returns the DepSet being built by this DepSetBuilder.  The DepSetBuilder retains its contents
+// for creating more DepSets.
+func (b *DepSetBuilder) Build() *DepSet {
+	return &DepSet{*b.depSetBuilder.Build()}
+}
+
+// ToList returns the DepSet flattened to a list.  The order in the list is based on the order
+// of the DepSet.  POSTORDER and PREORDER orders return a postordered or preordered left to right
+// flattened list.  TOPOLOGICAL returns a list that guarantees that elements of children are listed
+// after all of their parents (unless there are duplicate direct elements in the DepSet or any of
+// its transitive dependencies, in which case the ordering of the duplicated element is not
+// guaranteed).
+func (d *DepSet) ToList() Paths {
+	if d == nil {
+		return nil
+	}
+	return d.toList(func(paths interface{}) interface{} {
+		return FirstUniquePaths(paths.(Paths))
+	}).(Paths)
+}
+
+// ToSortedList returns the direct and transitive contents of a DepSet in lexically sorted order
+// with duplicates removed.
+func (d *DepSet) ToSortedList() Paths {
+	if d == nil {
+		return nil
+	}
+	paths := d.ToList()
+	return SortedUniquePaths(paths)
+}
diff --git a/android/depset_test.go b/android/depset_test.go
index c328127..955ccb0 100644
--- a/android/depset_test.go
+++ b/android/depset_test.go
@@ -17,6 +17,7 @@
 import (
 	"fmt"
 	"reflect"
+	"strconv"
 	"strings"
 	"testing"
 )
@@ -108,6 +109,7 @@
 			name: "builderReuse",
 			depSet: func(t *testing.T, order DepSetOrder) *DepSet {
 				assertEquals := func(t *testing.T, w, g Paths) {
+					t.Helper()
 					if !reflect.DeepEqual(w, g) {
 						t.Errorf("want %q, got %q", w, g)
 					}
@@ -302,3 +304,87 @@
 		})
 	}
 }
+
+func Test_firstUnique(t *testing.T) {
+	f := func(t *testing.T, imp func([]string) []string, in, want []string) {
+		t.Helper()
+		out := imp(in)
+		if !reflect.DeepEqual(out, want) {
+			t.Errorf("incorrect output:")
+			t.Errorf("     input: %#v", in)
+			t.Errorf("  expected: %#v", want)
+			t.Errorf("       got: %#v", out)
+		}
+	}
+
+	for _, testCase := range firstUniqueStringsTestCases {
+		t.Run("list", func(t *testing.T) {
+			f(t, func(s []string) []string {
+				return firstUniqueList(s).([]string)
+			}, testCase.in, testCase.out)
+		})
+		t.Run("map", func(t *testing.T) {
+			f(t, func(s []string) []string {
+				return firstUniqueMap(s).([]string)
+			}, testCase.in, testCase.out)
+		})
+	}
+}
+
+func Benchmark_firstUnique(b *testing.B) {
+	implementations := []struct {
+		name string
+		f    func([]string) []string
+	}{
+		{
+			name: "list",
+			f: func(slice []string) []string {
+				return firstUniqueList(slice).([]string)
+			},
+		},
+		{
+			name: "map",
+			f: func(slice []string) []string {
+				return firstUniqueMap(slice).([]string)
+			},
+		},
+		{
+			name: "optimal",
+			f: func(slice []string) []string {
+				return firstUnique(slice).([]string)
+			},
+		},
+	}
+	const maxSize = 1024
+	uniqueStrings := make([]string, maxSize)
+	for i := range uniqueStrings {
+		uniqueStrings[i] = strconv.Itoa(i)
+	}
+	sameString := make([]string, maxSize)
+	for i := range sameString {
+		sameString[i] = uniqueStrings[0]
+	}
+
+	f := func(b *testing.B, imp func([]string) []string, s []string) {
+		for i := 0; i < b.N; i++ {
+			b.ReportAllocs()
+			s = append([]string(nil), s...)
+			imp(s)
+		}
+	}
+
+	for n := 1; n <= maxSize; n <<= 1 {
+		b.Run(strconv.Itoa(n), func(b *testing.B) {
+			for _, implementation := range implementations {
+				b.Run(implementation.name, func(b *testing.B) {
+					b.Run("same", func(b *testing.B) {
+						f(b, implementation.f, sameString[:n])
+					})
+					b.Run("unique", func(b *testing.B) {
+						f(b, implementation.f, uniqueStrings[:n])
+					})
+				})
+			}
+		})
+	}
+}
diff --git a/android/util_test.go b/android/util_test.go
index 25b52ca..fa26c77 100644
--- a/android/util_test.go
+++ b/android/util_test.go
@@ -593,6 +593,10 @@
 			name: "map",
 			f:    firstUniqueStringsMap,
 		},
+		{
+			name: "optimal",
+			f:    FirstUniqueStrings,
+		},
 	}
 	const maxSize = 1024
 	uniqueStrings := make([]string, maxSize)