diff --git a/gopls/internal/regtest/bench/bench_test.go b/gopls/internal/regtest/bench/bench_test.go
index 0801ecf753..360e9563c9 100644
--- a/gopls/internal/regtest/bench/bench_test.go
+++ b/gopls/internal/regtest/bench/bench_test.go
@@ -7,6 +7,8 @@ package bench
 import (
 	"flag"
 	"fmt"
+	"os"
+	"runtime/pprof"
 	"testing"
 	"time"
 
@@ -131,8 +133,9 @@ func TestBenchmarkSymbols(t *testing.T) {
 }
 
 var (
-	benchDir  = flag.String("didchange_dir", "", "If set, run benchmarks in this dir. Must also set regtest_bench_file.")
-	benchFile = flag.String("didchange_file", "", "The file to modify")
+	benchDir     = flag.String("didchange_dir", "", "If set, run benchmarks in this dir. Must also set regtest_bench_file.")
+	benchFile    = flag.String("didchange_file", "", "The file to modify")
+	benchProfile = flag.String("didchange_cpuprof", "", "file to write cpu profiling data to")
 )
 
 // TestBenchmarkDidChange benchmarks modifications of a single file by making
@@ -162,6 +165,17 @@ func TestBenchmarkDidChange(t *testing.T) {
 		// Insert the text we'll be modifying at the top of the file.
 		env.EditBuffer(*benchFile, fake.Edit{Text: "// __REGTEST_PLACEHOLDER_0__\n"})
 		result := testing.Benchmark(func(b *testing.B) {
+			if *benchProfile != "" {
+				profile, err := os.Create(*benchProfile)
+				if err != nil {
+					t.Fatal(err)
+				}
+				defer profile.Close()
+				if err := pprof.StartCPUProfile(profile); err != nil {
+					t.Fatal(err)
+				}
+				defer pprof.StopCPUProfile()
+			}
 			b.ResetTimer()
 			for i := 0; i < b.N; i++ {
 				env.EditBuffer(*benchFile, fake.Edit{
diff --git a/internal/lsp/fake/sandbox.go b/internal/lsp/fake/sandbox.go
index 34f1ba180c..f628f2d540 100644
--- a/internal/lsp/fake/sandbox.go
+++ b/internal/lsp/fake/sandbox.go
@@ -163,7 +163,7 @@ func UnpackTxt(txt string) map[string][]byte {
 }
 
 func validateConfig(config SandboxConfig) error {
-	if filepath.IsAbs(config.Workdir) && (config.Files != nil || config.InGoPath) {
+	if filepath.IsAbs(config.Workdir) && (len(config.Files) > 0 || config.InGoPath) {
 		return errors.New("absolute Workdir cannot be set in conjunction with Files or InGoPath")
 	}
 	if config.Workdir != "" && config.InGoPath {