go reader(resource, numIterations, &activity, cdone)
		}
		go writer(resource, numIterations, &activity, cdone)
		for ; i < numReaders; i++ {
			go reader(resource, numIterations, &activity, cdone)
		}
		// Wait for the 2 writers and all readers to finish.
		for i := 0; i < 2+numReaders; i++ {
			<-cdone
		}
	})
}

// Borrowed from rwmutex_test.go
func TestRWMutex(t *testing.T) {

// 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.

package gover

import (
	"internal/goversion"
	"runtime"
	"strconv"
)

// TestVersion is initialized in the go command test binary
// to be $TESTGO_VERSION, to allow tests to override the
// go command's idea of its own version as returned by Local.
var TestVersion string

// Copyright 2009 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 ignore

/*
Input to cgo.

GOARCH=amd64 go tool cgo -godefs defs_openbsd.go
GOARCH=386 go tool cgo -godefs defs_openbsd.go
GOARCH=arm go tool cgo -godefs defs_openbsd.go
GOARCH=arm64 go tool cgo -godefs defs_openbsd.go
GOARCH=mips64 go tool cgo -godefs defs_openbsd.go
*/

	go func() {
		for i := 0; i < 10000; i++ {
			m[5] = 0
			runtime.Gosched()
		}
		c <- struct{}{}
	}()
	go func() {
		for i := 0; i < 10000; i++ {
			m[6] = 0
			runtime.Gosched()
		}
		c <- struct{}{}
	}()
	<-c
	<-c
}

func concurrentMapReadWrite() {
	m := map[int]int{}
	c := make(chan struct{})
	go func() {
		for i := 0; i < 10000; i++ {
			m[5] = 0
			runtime.Gosched()

// Copyright 2016 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 generate

package registry

// Copyright 2018 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 unmarshal

import (
	_ "embed"
	"go/ast"
	"go/types"

	"golang.org/x/tools/go/analysis"
	"golang.org/x/tools/go/analysis/passes/inspect"
	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
	"golang.org/x/tools/go/ast/inspector"
	"golang.org/x/tools/go/types/typeutil"

// Copyright 2018 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 modcmd

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io/fs"
	"os"
	"runtime"

	"cmd/go/internal/base"
	"cmd/go/internal/gover"
	"cmd/go/internal/modfetch"
	"cmd/go/internal/modload"

	"golang.org/x/mod/module"
	"golang.org/x/mod/sumdb/dirhash"
)

// Copyright 2014 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.

// Pprof interprets and displays profiles of Go programs.
//
// Basic usage:
//
//	go tool pprof binary profile
//
// For detailed usage information:
//
//	go tool pprof -h
//
// For an example, see https://blog.golang.org/profiling-go-programs.

func TestTestRun(t *testing.T) {
	testenv.MustHaveGoRun(t)
	testenv.MustHaveCGO(t)

	for _, file := range [...]string{
		"chain.go",
		"fib.go",
		"hello.go",
	} {
		file := file
		wantFile := strings.Replace(file, ".go", ".out", 1)
		t.Run(file, func(t *testing.T) {
			cmd := exec.Command("go", "run", file)
			got, err := cmd.CombinedOutput()
			if err != nil {
				t.Fatalf("%v: %s\n%s", cmd, err, got)
			}

	}

	// 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 {