1 files changed, 57 insertions, 0 deletions
diff --git a/src/cmd/link/internal/ld/deadcode_test.go b/src/cmd/link/internal/ld/deadcode_test.go
new file mode 100644
index 0000000..b756091
--- /dev/null
+++ b/src/cmd/link/internal/ld/deadcode_test.go
@@ -0,0 +1,57 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ld
+
+import (
+	"bytes"
+	"internal/testenv"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+)
+
+func TestDeadcode(t *testing.T) {
+	testenv.MustHaveGoBuild(t)
+	t.Parallel()
+
+	tmpdir, err := ioutil.TempDir("", "TestDeadcode")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	tests := []struct {
+		src      string
+		pos, neg string // positive and negative patterns
+	}{
+		{"reflectcall", "", "main.T.M"},
+		{"typedesc", "", "type.main.T"},
+		{"ifacemethod", "", "main.T.M"},
+		{"ifacemethod2", "main.T.M", ""},
+		{"ifacemethod3", "main.S.M", ""},
+		{"ifacemethod4", "", "main.T.M"},
+	}
+	for _, test := range tests {
+		test := test
+		t.Run(test.src, func(t *testing.T) {
+			t.Parallel()
+			src := filepath.Join("testdata", "deadcode", test.src+".go")
+			exe := filepath.Join(tmpdir, test.src+".exe")
+			cmd := exec.Command(testenv.GoToolPath(t), "build", "-ldflags=-dumpdep", "-o", exe, src)
+			out, err := cmd.CombinedOutput()
+			if err != nil {
+				t.Fatalf("%v: %v:\n%s", cmd.Args, err, out)
+			}
+			if test.pos != "" && !bytes.Contains(out, []byte(test.pos)) {
+				t.Errorf("%s should be reachable. Output:\n%s", test.pos, out)
+			}
+			if test.neg != "" && bytes.Contains(out, []byte(test.neg)) {
+				t.Errorf("%s should not be reachable. Output:\n%s", test.neg, out)
+			}
+		})
+	}
+}