12 files changed, 264 insertions, 90 deletions

diff --git a/misc/swig/callback/callback.go b/misc/swig/callback/callback.go
deleted file mode 100644
index 0d6e97f05b..0000000000
--- a/misc/swig/callback/callback.go
+++ /dev/null
@@ -1,11 +0,0 @@
-// Copyright 2012 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 callback
-
-type GoCallback struct{}
-
-func (p *GoCallback) Run() string {
-	return "GoCallback.Run"
-}
diff --git a/misc/swig/callback/callback_test.go b/misc/swig/callback/callback_test.go
deleted file mode 100644
index 0c8a3004da..0000000000
--- a/misc/swig/callback/callback_test.go
+++ /dev/null
@@ -1,33 +0,0 @@
-// Copyright 2012 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 callback
-
-import (
-	"testing"
-)
-
-func TestCall(t *testing.T) {
-	c := NewCaller()
-	cb := NewCallback()
-
-	c.SetCallback(cb)
-	s := c.Call()
-	if s != "Callback::run" {
-		t.Errorf("unexpected string from Call: %q", s)
-	}
-	c.DelCallback()
-}
-
-func TestCallback(t *testing.T) {
-	c := NewCaller()
-	cb := NewDirectorCallback(&GoCallback{})
-	c.SetCallback(cb)
-	s := c.Call()
-	if s != "GoCallback.Run" {
-		t.Errorf("unexpected string from Call with callback: %q", s)
-	}
-	c.DelCallback()
-	DeleteDirectorCallback(cb)
-}
diff --git a/misc/swig/nocgo_test.go b/misc/swig/nocgo_test.go
new file mode 100644
index 0000000000..c68b97d6b6
--- /dev/null
+++ b/misc/swig/nocgo_test.go
@@ -0,0 +1,7 @@
+// Copyright 2023 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.
+
+// This file is just to avoid build errors if there's no cgo.
+
+package swig
diff --git a/misc/swig/stdio/file.go b/misc/swig/stdio/file.go
deleted file mode 100644
index a582f776f6..0000000000
--- a/misc/swig/stdio/file.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright 2017 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.
-
-// This file is here just to cause problems.
-// file.swig turns into a file also named file.go.
-// Make sure cmd/go keeps them separate
-// when both are passed to cgo.
-
-package file
-
-//int F(void) { return 1; }
-import "C"
-
-func F() int { return int(C.F()) }
diff --git a/misc/swig/stdio/file_test.go b/misc/swig/stdio/file_test.go
deleted file mode 100644
index aea92aafd5..0000000000
--- a/misc/swig/stdio/file_test.go
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright 2012 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 file
-
-import "testing"
-
-// Open this file itself and verify that the first few characters are
-// as expected.
-func TestRead(t *testing.T) {
-	f := Fopen("file_test.go", "r")
-	if f.Swigcptr() == 0 {
-		t.Fatal("fopen failed")
-	}
-	if Fgetc(f) != '/' || Fgetc(f) != '/' || Fgetc(f) != ' ' || Fgetc(f) != 'C' {
-		t.Error("read unexpected characters")
-	}
-	if Fclose(f) != 0 {
-		t.Error("fclose failed")
-	}
-}
-
-func TestF(t *testing.T) {
-	if x := F(); x != 1 {
-		t.Fatalf("x = %d, want 1", x)
-	}
-}
diff --git a/misc/swig/swig_test.go b/misc/swig/swig_test.go
new file mode 100644
index 0000000000..cbe062ae41
--- /dev/null
+++ b/misc/swig/swig_test.go
@@ -0,0 +1,149 @@
+// Copyright 2023 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.
+
+//go:build cgo
+
+package swig
+
+import (
+	"bytes"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+	"sync"
+	"testing"
+)
+
+func TestStdio(t *testing.T) {
+	mustHaveSwig(t)
+	run(t, "testdata/stdio", false)
+}
+
+func TestCall(t *testing.T) {
+	mustHaveSwig(t)
+	mustHaveCxx(t)
+	run(t, "testdata/callback", false, "Call")
+	t.Run("lto", func(t *testing.T) { run(t, "testdata/callback", true, "Call") })
+}
+
+func TestCallback(t *testing.T) {
+	mustHaveSwig(t)
+	mustHaveCxx(t)
+	run(t, "testdata/callback", false, "Callback")
+	t.Run("lto", func(t *testing.T) { run(t, "testdata/callback", true, "Callback") })
+}
+
+func run(t *testing.T, dir string, lto bool, args ...string) {
+	runArgs := append([]string{"run", "."}, args...)
+	cmd := exec.Command("go", runArgs...)
+	cmd.Dir = dir
+	if lto {
+		const cflags = "-flto -Wno-lto-type-mismatch -Wno-unknown-warning-option"
+		cmd.Env = append(cmd.Environ(),
+			"CGO_CFLAGS="+cflags,
+			"CGO_CXXFLAGS="+cflags,
+			"CGO_LDFLAGS="+cflags)
+	}
+	out, err := cmd.CombinedOutput()
+	if string(out) != "OK\n" {
+		t.Errorf("%s", string(out))
+	}
+	if err != nil {
+		t.Errorf("%s", err)
+	}
+}
+
+func mustHaveCxx(t *testing.T) {
+	// Ask the go tool for the CXX it's configured to use.
+	cxx, err := exec.Command("go", "env", "CXX").CombinedOutput()
+	if err != nil {
+		t.Fatalf("go env CXX failed: %s", err)
+	}
+	cxx = bytes.TrimSuffix(cxx, []byte("\n"))
+	// TODO(austin): "go env CXX" can return a quoted list. Use quoted.Split.
+	p, err := exec.LookPath(string(cxx))
+	if p == "" {
+		t.Skipf("test requires C++ compiler, but failed to find %s: %s", string(cxx), err)
+	}
+}
+
+var (
+	swigOnce sync.Once
+	haveSwig bool
+)
+
+func mustHaveSwig(t *testing.T) {
+	swigOnce.Do(func() {
+		mustHaveSwigOnce(t)
+		haveSwig = true
+	})
+	// The first call will skip t with a nice message. On later calls, we just skip.
+	if !haveSwig {
+		t.Skip("swig not found")
+	}
+}
+
+func mustHaveSwigOnce(t *testing.T) {
+	swig, err := exec.LookPath("swig")
+	if err != nil {
+		t.Skipf("swig not in PATH: %s", err)
+	}
+
+	// Check that swig was installed with Go support by checking
+	// that a go directory exists inside the swiglib directory.
+	// See https://golang.org/issue/23469.
+	output, err := exec.Command(swig, "-go", "-swiglib").Output()
+	if err != nil {
+		t.Skip("swig is missing Go support")
+	}
+	swigDir := strings.TrimSpace(string(output))
+
+	_, err = os.Stat(filepath.Join(swigDir, "go"))
+	if err != nil {
+		t.Skip("swig is missing Go support")
+	}
+
+	// Check that swig has a new enough version.
+	// See https://golang.org/issue/22858.
+	out, err := exec.Command(swig, "-version").CombinedOutput()
+	if err != nil {
+		t.Skipf("failed to get swig version:%s\n%s", err, string(out))
+	}
+
+	re := regexp.MustCompile(`[vV]ersion +(\d+)([.]\d+)?([.]\d+)?`)
+	matches := re.FindSubmatch(out)
+	if matches == nil {
+		// Can't find version number; hope for the best.
+		t.Logf("failed to find swig version, continuing")
+		return
+	}
+
+	var parseError error
+	atoi := func(s string) int {
+		x, err := strconv.Atoi(s)
+		if err != nil && parseError == nil {
+			parseError = err
+		}
+		return x
+	}
+	var major, minor, patch int
+	major = atoi(string(matches[1]))
+	if len(matches[2]) > 0 {
+		minor = atoi(string(matches[2][1:]))
+	}
+	if len(matches[3]) > 0 {
+		patch = atoi(string(matches[3][1:]))
+	}
+	if parseError != nil {
+		t.Logf("error parsing swig version %q, continuing anyway: %s", string(matches[0]), parseError)
+		return
+	}
+	t.Logf("found swig version %d.%d.%d", major, minor, patch)
+	if major < 3 || (major == 3 && minor == 0 && patch < 6) {
+		t.Skip("test requires swig 3.0.6 or later")
+	}
+}
diff --git a/misc/swig/callback/callback.cc b/misc/swig/testdata/callback/main.cc
index 88bd49c57f..7de917cde4 100644
--- a/misc/swig/callback/callback.cc
+++ b/misc/swig/testdata/callback/main.cc
@@ -6,7 +6,7 @@
 // included in the package.
 
 #include <string>
-#include "callback.h"
+#include "main.h"
 
 std::string Caller::call() {
 	if (callback_ != 0)
diff --git a/misc/swig/testdata/callback/main.go b/misc/swig/testdata/callback/main.go
new file mode 100644
index 0000000000..73034a0c7c
--- /dev/null
+++ b/misc/swig/testdata/callback/main.go
@@ -0,0 +1,60 @@
+// Copyright 2012 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 main
+
+import (
+	"fmt"
+	"os"
+)
+
+func main() {
+	if len(os.Args) != 2 {
+		fatal("usage: callback testname")
+	}
+	switch os.Args[1] {
+	default:
+		fatal("unknown test %q", os.Args[1])
+	case "Call":
+		testCall()
+	case "Callback":
+		testCallback()
+	}
+	println("OK")
+}
+
+func fatal(f string, args ...any) {
+	fmt.Fprintln(os.Stderr, fmt.Sprintf(f, args...))
+	os.Exit(1)
+}
+
+type GoCallback struct{}
+
+func (p *GoCallback) Run() string {
+	return "GoCallback.Run"
+}
+
+func testCall() {
+	c := NewCaller()
+	cb := NewCallback()
+
+	c.SetCallback(cb)
+	s := c.Call()
+	if s != "Callback::run" {
+		fatal("unexpected string from Call: %q", s)
+	}
+	c.DelCallback()
+}
+
+func testCallback() {
+	c := NewCaller()
+	cb := NewDirectorCallback(&GoCallback{})
+	c.SetCallback(cb)
+	s := c.Call()
+	if s != "GoCallback.Run" {
+		fatal("unexpected string from Call with callback: %q", s)
+	}
+	c.DelCallback()
+	DeleteDirectorCallback(cb)
+}
diff --git a/misc/swig/callback/callback.h b/misc/swig/testdata/callback/main.h
index 4b661060d8..4b661060d8 100644
--- a/misc/swig/callback/callback.h
+++ b/misc/swig/testdata/callback/main.h
diff --git a/misc/swig/callback/callback.swigcxx b/misc/swig/testdata/callback/main.swigcxx
index 6181fe9c7e..0fd73d6362 100644
--- a/misc/swig/callback/callback.swigcxx
+++ b/misc/swig/testdata/callback/main.swigcxx
@@ -8,11 +8,11 @@
 
 %{
 #include <string>
-#include "callback.h"
+#include "main.h"
 %}
 
 %include "std_string.i"
 
 %feature("director");
 
-%include "callback.h"
+%include "main.h"
diff --git a/misc/swig/testdata/stdio/main.go b/misc/swig/testdata/stdio/main.go
new file mode 100644
index 0000000000..0296dd3224
--- /dev/null
+++ b/misc/swig/testdata/stdio/main.go
@@ -0,0 +1,45 @@
+// Copyright 2017 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.
+
+// This file is here just to cause problems.
+// main.swig turns into a file also named main.go.
+// Make sure cmd/go keeps them separate
+// when both are passed to cgo.
+
+package main
+
+//int F(void) { return 1; }
+import "C"
+import (
+	"fmt"
+	"os"
+)
+
+func F() int { return int(C.F()) }
+
+func main() {
+	if x := int(C.F()); x != 1 {
+		fatal("x = %d, want 1", x)
+	}
+
+	// Open this file itself and verify that the first few characters are
+	// as expected.
+	f := Fopen("main.go", "r")
+	if f.Swigcptr() == 0 {
+		fatal("fopen failed")
+	}
+	if Fgetc(f) != '/' || Fgetc(f) != '/' || Fgetc(f) != ' ' || Fgetc(f) != 'C' {
+		fatal("read unexpected characters")
+	}
+	if Fclose(f) != 0 {
+		fatal("fclose failed")
+	}
+
+	println("OK")
+}
+
+func fatal(f string, args ...any) {
+	fmt.Fprintln(os.Stderr, fmt.Sprintf(f, args...))
+	os.Exit(1)
+}
diff --git a/misc/swig/stdio/file.swig b/misc/swig/testdata/stdio/main.swig
index b28ae0a6b7..b28ae0a6b7 100644
--- a/misc/swig/stdio/file.swig
+++ b/misc/swig/testdata/stdio/main.swig