Source file src/cmd/internal/testdir/testdir_test.go

Documentation: cmd/internal/testdir

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package testdir_test runs tests in the GOROOT/test directory.
     6  package testdir_test
     7  
     8  import (
     9  	"bytes"
    10  	"encoding/json"
    11  	"errors"
    12  	"flag"
    13  	"fmt"
    14  	"go/build"
    15  	"go/build/constraint"
    16  	"hash/fnv"
    17  	"internal/testenv"
    18  	"io"
    19  	"io/fs"
    20  	"log"
    21  	"os"
    22  	"os/exec"
    23  	"path"
    24  	"path/filepath"
    25  	"regexp"
    26  	"runtime"
    27  	"slices"
    28  	"sort"
    29  	"strconv"
    30  	"strings"
    31  	"sync"
    32  	"testing"
    33  	"time"
    34  	"unicode"
    35  )
    36  
    37  var (
    38  	allCodegen     = flag.Bool("all_codegen", defaultAllCodeGen(), "run all goos/goarch for codegen")
    39  	runSkips       = flag.Bool("run_skips", false, "run skipped tests (ignore skip and build tags)")
    40  	linkshared     = flag.Bool("linkshared", false, "")
    41  	updateErrors   = flag.Bool("update_errors", false, "update error messages in test file based on compiler output")
    42  	runoutputLimit = flag.Int("l", defaultRunOutputLimit(), "number of parallel runoutput tests to run")
    43  	force          = flag.Bool("f", false, "ignore expected-failure test lists")
    44  	target         = flag.String("target", "", "cross-compile tests for `goos/goarch`")
    45  
    46  	shard  = flag.Int("shard", 0, "shard index to run. Only applicable if -shards is non-zero.")
    47  	shards = flag.Int("shards", 0, "number of shards. If 0, all tests are run. This is used by the continuous build.")
    48  )
    49  
    50  // defaultAllCodeGen returns the default value of the -all_codegen
    51  // flag. By default, we prefer to be fast (returning false), except on
    52  // the linux-amd64 builder that's already very fast, so we get more
    53  // test coverage on trybots. See https://go.dev/issue/34297.
    54  func defaultAllCodeGen() bool {
    55  	return os.Getenv("GO_BUILDER_NAME") == "linux-amd64"
    56  }
    57  
    58  var (
    59  	// Package-scoped variables that are initialized at the start of Test.
    60  	goTool       string
    61  	goos         string // Target GOOS
    62  	goarch       string // Target GOARCH
    63  	cgoEnabled   bool
    64  	goExperiment string
    65  	goDebug      string
    66  
    67  	// dirs are the directories to look for *.go files in.
    68  	// TODO(bradfitz): just use all directories?
    69  	dirs = []string{".", "ken", "chan", "interface", "syntax", "dwarf", "fixedbugs", "codegen", "runtime", "abi", "typeparam", "typeparam/mdempsky", "arenas"}
    70  )
    71  
    72  // Test is the main entrypoint that runs tests in the GOROOT/test directory.
    73  //
    74  // Each .go file test case in GOROOT/test is registered as a subtest with a
    75  // a full name like "Test/fixedbugs/bug000.go" ('/'-separated relative path).
    76  func Test(t *testing.T) {
    77  	if *target != "" {
    78  		// When -target is set, propagate it to GOOS/GOARCH in our environment
    79  		// so that all commands run with the target GOOS/GOARCH.
    80  		//
    81  		// We do this before even calling "go env", because GOOS/GOARCH can
    82  		// affect other settings we get from go env (notably CGO_ENABLED).
    83  		goos, goarch, ok := strings.Cut(*target, "/")
    84  		if !ok {
    85  			t.Fatalf("bad -target flag %q, expected goos/goarch", *target)
    86  		}
    87  		t.Setenv("GOOS", goos)
    88  		t.Setenv("GOARCH", goarch)
    89  	}
    90  
    91  	goTool = testenv.GoToolPath(t)
    92  	cmd := exec.Command(goTool, "env", "-json")
    93  	stdout, err := cmd.StdoutPipe()
    94  	if err != nil {
    95  		t.Fatal("StdoutPipe:", err)
    96  	}
    97  	if err := cmd.Start(); err != nil {
    98  		t.Fatal("Start:", err)
    99  	}
   100  	var env struct {
   101  		GOOS         string
   102  		GOARCH       string
   103  		GOEXPERIMENT string
   104  		GODEBUG      string
   105  		CGO_ENABLED  string
   106  	}
   107  	if err := json.NewDecoder(stdout).Decode(&env); err != nil {
   108  		t.Fatal("Decode:", err)
   109  	}
   110  	if err := cmd.Wait(); err != nil {
   111  		t.Fatal("Wait:", err)
   112  	}
   113  	goos = env.GOOS
   114  	goarch = env.GOARCH
   115  	cgoEnabled, _ = strconv.ParseBool(env.CGO_ENABLED)
   116  	goExperiment = env.GOEXPERIMENT
   117  	goDebug = env.GODEBUG
   118  
   119  	common := testCommon{
   120  		gorootTestDir: filepath.Join(testenv.GOROOT(t), "test"),
   121  		runoutputGate: make(chan bool, *runoutputLimit),
   122  	}
   123  
   124  	// cmd/distpack deletes GOROOT/test, so skip the test if it isn't present.
   125  	// cmd/distpack also requires GOROOT/VERSION to exist, so use that to
   126  	// suppress false-positive skips.
   127  	if _, err := os.Stat(common.gorootTestDir); os.IsNotExist(err) {
   128  		if _, err := os.Stat(filepath.Join(testenv.GOROOT(t), "VERSION")); err == nil {
   129  			t.Skipf("skipping: GOROOT/test not present")
   130  		}
   131  	}
   132  
   133  	for _, dir := range dirs {
   134  		for _, goFile := range goFiles(t, dir) {
   135  			test := test{testCommon: common, dir: dir, goFile: goFile}
   136  			t.Run(path.Join(dir, goFile), func(t *testing.T) {
   137  				t.Parallel()
   138  				test.T = t
   139  				testError := test.run()
   140  				wantError := test.expectFail() && !*force
   141  				if testError != nil {
   142  					if wantError {
   143  						t.Log(testError.Error() + " (expected)")
   144  					} else {
   145  						t.Fatal(testError)
   146  					}
   147  				} else if wantError {
   148  					t.Fatal("unexpected success")
   149  				}
   150  			})
   151  		}
   152  	}
   153  }
   154  
   155  func shardMatch(name string) bool {
   156  	if *shards <= 1 {
   157  		return true
   158  	}
   159  	h := fnv.New32()
   160  	io.WriteString(h, name)
   161  	return int(h.Sum32()%uint32(*shards)) == *shard
   162  }
   163  
   164  func goFiles(t *testing.T, dir string) []string {
   165  	f, err := os.Open(filepath.Join(testenv.GOROOT(t), "test", dir))
   166  	if err != nil {
   167  		t.Fatal(err)
   168  	}
   169  	dirnames, err := f.Readdirnames(-1)
   170  	f.Close()
   171  	if err != nil {
   172  		t.Fatal(err)
   173  	}
   174  	names := []string{}
   175  	for _, name := range dirnames {
   176  		if !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go") && shardMatch(name) {
   177  			names = append(names, name)
   178  		}
   179  	}
   180  	sort.Strings(names)
   181  	return names
   182  }
   183  
   184  type runCmd func(...string) ([]byte, error)
   185  
   186  func compileFile(runcmd runCmd, longname string, flags []string) (out []byte, err error) {
   187  	cmd := []string{goTool, "tool", "compile", "-e", "-p=p", "-importcfg=" + stdlibImportcfgFile()}
   188  	cmd = append(cmd, flags...)
   189  	if *linkshared {
   190  		cmd = append(cmd, "-dynlink", "-installsuffix=dynlink")
   191  	}
   192  	cmd = append(cmd, longname)
   193  	return runcmd(cmd...)
   194  }
   195  
   196  func compileInDir(runcmd runCmd, dir string, flags []string, importcfg string, pkgname string, names ...string) (out []byte, err error) {
   197  	if importcfg == "" {
   198  		importcfg = stdlibImportcfgFile()
   199  	}
   200  	cmd := []string{goTool, "tool", "compile", "-e", "-D", "test", "-importcfg=" + importcfg}
   201  	if pkgname == "main" {
   202  		cmd = append(cmd, "-p=main")
   203  	} else {
   204  		pkgname = path.Join("test", strings.TrimSuffix(names[0], ".go"))
   205  		cmd = append(cmd, "-o", pkgname+".a", "-p", pkgname)
   206  	}
   207  	cmd = append(cmd, flags...)
   208  	if *linkshared {
   209  		cmd = append(cmd, "-dynlink", "-installsuffix=dynlink")
   210  	}
   211  	for _, name := range names {
   212  		cmd = append(cmd, filepath.Join(dir, name))
   213  	}
   214  	return runcmd(cmd...)
   215  }
   216  
   217  var stdlibImportcfgStringOnce sync.Once // TODO(#56102): Use sync.OnceValue once available. Also below.
   218  var stdlibImportcfgString string
   219  
   220  func stdlibImportcfg() string {
   221  	stdlibImportcfgStringOnce.Do(func() {
   222  		output, err := exec.Command(goTool, "list", "-export", "-f", "{{if .Export}}packagefile {{.ImportPath}}={{.Export}}{{end}}", "std").Output()
   223  		if err != nil {
   224  			log.Fatal(err)
   225  		}
   226  		stdlibImportcfgString = string(output)
   227  	})
   228  	return stdlibImportcfgString
   229  }
   230  
   231  var stdlibImportcfgFilenameOnce sync.Once
   232  var stdlibImportcfgFilename string
   233  
   234  func stdlibImportcfgFile() string {
   235  	stdlibImportcfgFilenameOnce.Do(func() {
   236  		tmpdir, err := os.MkdirTemp("", "importcfg")
   237  		if err != nil {
   238  			log.Fatal(err)
   239  		}
   240  		filename := filepath.Join(tmpdir, "importcfg")
   241  		err = os.WriteFile(filename, []byte(stdlibImportcfg()), 0644)
   242  		if err != nil {
   243  			log.Fatal(err)
   244  		}
   245  		stdlibImportcfgFilename = filename
   246  	})
   247  	return stdlibImportcfgFilename
   248  }
   249  
   250  func linkFile(runcmd runCmd, goname string, importcfg string, ldflags []string) (err error) {
   251  	if importcfg == "" {
   252  		importcfg = stdlibImportcfgFile()
   253  	}
   254  	pfile := strings.Replace(goname, ".go", ".o", -1)
   255  	cmd := []string{goTool, "tool", "link", "-w", "-o", "a.exe", "-importcfg=" + importcfg}
   256  	if *linkshared {
   257  		cmd = append(cmd, "-linkshared", "-installsuffix=dynlink")
   258  	}
   259  	if ldflags != nil {
   260  		cmd = append(cmd, ldflags...)
   261  	}
   262  	cmd = append(cmd, pfile)
   263  	_, err = runcmd(cmd...)
   264  	return
   265  }
   266  
   267  type testCommon struct {
   268  	// gorootTestDir is the GOROOT/test directory path.
   269  	gorootTestDir string
   270  
   271  	// runoutputGate controls the max number of runoutput tests
   272  	// executed in parallel as they can each consume a lot of memory.
   273  	runoutputGate chan bool
   274  }
   275  
   276  // test is a single test case in the GOROOT/test directory.
   277  type test struct {
   278  	testCommon
   279  	*testing.T
   280  	// dir and goFile identify the test case.
   281  	// For example, "fixedbugs", "bug000.go".
   282  	dir, goFile string
   283  }
   284  
   285  // expectFail reports whether the (overall) test recipe is
   286  // expected to fail under the current build+test configuration.
   287  func (t test) expectFail() bool {
   288  	failureSets := []map[string]bool{types2Failures}
   289  
   290  	// Note: gccgo supports more 32-bit architectures than this, but
   291  	// hopefully the 32-bit failures are fixed before this matters.
   292  	switch goarch {
   293  	case "386", "arm", "mips", "mipsle":
   294  		failureSets = append(failureSets, types2Failures32Bit)
   295  	}
   296  
   297  	testName := path.Join(t.dir, t.goFile) // Test name is '/'-separated.
   298  
   299  	for _, set := range failureSets {
   300  		if set[testName] {
   301  			return true
   302  		}
   303  	}
   304  	return false
   305  }
   306  
   307  func (t test) goFileName() string {
   308  	return filepath.Join(t.dir, t.goFile)
   309  }
   310  
   311  func (t test) goDirName() string {
   312  	return filepath.Join(t.dir, strings.Replace(t.goFile, ".go", ".dir", -1))
   313  }
   314  
   315  // goDirFiles returns .go files in dir.
   316  func goDirFiles(dir string) (filter []fs.DirEntry, _ error) {
   317  	files, err := os.ReadDir(dir)
   318  	if err != nil {
   319  		return nil, err
   320  	}
   321  	for _, goFile := range files {
   322  		if filepath.Ext(goFile.Name()) == ".go" {
   323  			filter = append(filter, goFile)
   324  		}
   325  	}
   326  	return filter, nil
   327  }
   328  
   329  var packageRE = regexp.MustCompile(`(?m)^package ([\p{Lu}\p{Ll}\w]+)`)
   330  
   331  func getPackageNameFromSource(fn string) (string, error) {
   332  	data, err := os.ReadFile(fn)
   333  	if err != nil {
   334  		return "", err
   335  	}
   336  	pkgname := packageRE.FindStringSubmatch(string(data))
   337  	if pkgname == nil {
   338  		return "", fmt.Errorf("cannot find package name in %s", fn)
   339  	}
   340  	return pkgname[1], nil
   341  }
   342  
   343  // goDirPkg represents a Go package in some directory.
   344  type goDirPkg struct {
   345  	name  string
   346  	files []string
   347  }
   348  
   349  // goDirPackages returns distinct Go packages in dir.
   350  // If singlefilepkgs is set, each file is considered a separate package
   351  // even if the package names are the same.
   352  func goDirPackages(t *testing.T, dir string, singlefilepkgs bool) []*goDirPkg {
   353  	files, err := goDirFiles(dir)
   354  	if err != nil {
   355  		t.Fatal(err)
   356  	}
   357  	var pkgs []*goDirPkg
   358  	m := make(map[string]*goDirPkg)
   359  	for _, file := range files {
   360  		name := file.Name()
   361  		pkgname, err := getPackageNameFromSource(filepath.Join(dir, name))
   362  		if err != nil {
   363  			t.Fatal(err)
   364  		}
   365  		p, ok := m[pkgname]
   366  		if singlefilepkgs || !ok {
   367  			p = &goDirPkg{name: pkgname}
   368  			pkgs = append(pkgs, p)
   369  			m[pkgname] = p
   370  		}
   371  		p.files = append(p.files, name)
   372  	}
   373  	return pkgs
   374  }
   375  
   376  type context struct {
   377  	GOOS       string
   378  	GOARCH     string
   379  	cgoEnabled bool
   380  	noOptEnv   bool
   381  }
   382  
   383  // shouldTest looks for build tags in a source file and returns
   384  // whether the file should be used according to the tags.
   385  func shouldTest(src string, goos, goarch string) (ok bool, whyNot string) {
   386  	if *runSkips {
   387  		return true, ""
   388  	}
   389  	for _, line := range strings.Split(src, "\n") {
   390  		if strings.HasPrefix(line, "package ") {
   391  			break
   392  		}
   393  
   394  		if expr, err := constraint.Parse(line); err == nil {
   395  			gcFlags := os.Getenv("GO_GCFLAGS")
   396  			ctxt := &context{
   397  				GOOS:       goos,
   398  				GOARCH:     goarch,
   399  				cgoEnabled: cgoEnabled,
   400  				noOptEnv:   strings.Contains(gcFlags, "-N") || strings.Contains(gcFlags, "-l"),
   401  			}
   402  
   403  			if !expr.Eval(ctxt.match) {
   404  				return false, line
   405  			}
   406  		}
   407  	}
   408  	return true, ""
   409  }
   410  
   411  func (ctxt *context) match(name string) bool {
   412  	if name == "" {
   413  		return false
   414  	}
   415  
   416  	// Tags must be letters, digits, underscores or dots.
   417  	// Unlike in Go identifiers, all digits are fine (e.g., "386").
   418  	for _, c := range name {
   419  		if !unicode.IsLetter(c) && !unicode.IsDigit(c) && c != '_' && c != '.' {
   420  			return false
   421  		}
   422  	}
   423  
   424  	if slices.Contains(build.Default.ReleaseTags, name) {
   425  		return true
   426  	}
   427  
   428  	if strings.HasPrefix(name, "goexperiment.") {
   429  		return slices.Contains(build.Default.ToolTags, name)
   430  	}
   431  
   432  	if name == "cgo" && ctxt.cgoEnabled {
   433  		return true
   434  	}
   435  
   436  	if name == ctxt.GOOS || name == ctxt.GOARCH || name == "gc" {
   437  		return true
   438  	}
   439  
   440  	if ctxt.noOptEnv && name == "gcflags_noopt" {
   441  		return true
   442  	}
   443  
   444  	if name == "test_run" {
   445  		return true
   446  	}
   447  
   448  	return false
   449  }
   450  
   451  // goGcflags returns the -gcflags argument to use with go build / go run.
   452  // This must match the flags used for building the standard library,
   453  // or else the commands will rebuild any needed packages (like runtime)
   454  // over and over.
   455  func (test) goGcflags() string {
   456  	return "-gcflags=all=" + os.Getenv("GO_GCFLAGS")
   457  }
   458  
   459  func (test) goGcflagsIsEmpty() bool {
   460  	return "" == os.Getenv("GO_GCFLAGS")
   461  }
   462  
   463  var errTimeout = errors.New("command exceeded time limit")
   464  
   465  // run runs the test case.
   466  //
   467  // When there is a problem, run uses t.Fatal to signify that it's an unskippable
   468  // infrastructure error (such as failing to read an input file or the test recipe
   469  // being malformed), or it returns a non-nil error to signify a test case error.
   470  //
   471  // t.Error isn't used here to give the caller the opportunity to decide whether
   472  // the test case failing is expected before promoting it to a real test failure.
   473  // See expectFail and -f flag.
   474  func (t test) run() error {
   475  	srcBytes, err := os.ReadFile(filepath.Join(t.gorootTestDir, t.goFileName()))
   476  	if err != nil {
   477  		t.Fatal("reading test case .go file:", err)
   478  	} else if bytes.HasPrefix(srcBytes, []byte{'\n'}) {
   479  		t.Fatal(".go file source starts with a newline")
   480  	}
   481  	src := string(srcBytes)
   482  
   483  	// Execution recipe is contained in a comment in
   484  	// the first non-empty line that is not a build constraint.
   485  	var action string
   486  	for actionSrc := src; action == "" && actionSrc != ""; {
   487  		var line string
   488  		line, actionSrc, _ = strings.Cut(actionSrc, "\n")
   489  		if constraint.IsGoBuild(line) || constraint.IsPlusBuild(line) {
   490  			continue
   491  		}
   492  		action = strings.TrimSpace(strings.TrimPrefix(line, "//"))
   493  	}
   494  	if action == "" {
   495  		t.Fatalf("execution recipe not found in GOROOT/test/%s", t.goFileName())
   496  	}
   497  
   498  	// Check for build constraints only up to the actual code.
   499  	header, _, ok := strings.Cut(src, "\npackage")
   500  	if !ok {
   501  		header = action // some files are intentionally malformed
   502  	}
   503  	if ok, why := shouldTest(header, goos, goarch); !ok {
   504  		t.Skip(why)
   505  	}
   506  
   507  	var args, flags, runenv []string
   508  	var tim int
   509  	wantError := false
   510  	wantAuto := false
   511  	singlefilepkgs := false
   512  	f, err := splitQuoted(action)
   513  	if err != nil {
   514  		t.Fatal("invalid test recipe:", err)
   515  	}
   516  	if len(f) > 0 {
   517  		action = f[0]
   518  		args = f[1:]
   519  	}
   520  
   521  	// TODO: Clean up/simplify this switch statement.
   522  	switch action {
   523  	case "compile", "compiledir", "build", "builddir", "buildrundir", "run", "buildrun", "runoutput", "rundir", "runindir", "asmcheck":
   524  		// nothing to do
   525  	case "errorcheckandrundir":
   526  		wantError = false // should be no error if also will run
   527  	case "errorcheckwithauto":
   528  		action = "errorcheck"
   529  		wantAuto = true
   530  		wantError = true
   531  	case "errorcheck", "errorcheckdir", "errorcheckoutput":
   532  		wantError = true
   533  	case "skip":
   534  		if *runSkips {
   535  			break
   536  		}
   537  		t.Skip("skip")
   538  	default:
   539  		t.Fatalf("unknown pattern: %q", action)
   540  	}
   541  
   542  	goexp := goExperiment
   543  	godebug := goDebug
   544  
   545  	// collect flags
   546  	for len(args) > 0 && strings.HasPrefix(args[0], "-") {
   547  		switch args[0] {
   548  		case "-1":
   549  			wantError = true
   550  		case "-0":
   551  			wantError = false
   552  		case "-s":
   553  			singlefilepkgs = true
   554  		case "-t": // timeout in seconds
   555  			args = args[1:]
   556  			var err error
   557  			tim, err = strconv.Atoi(args[0])
   558  			if err != nil {
   559  				t.Fatalf("need number of seconds for -t timeout, got %s instead", args[0])
   560  			}
   561  			if s := os.Getenv("GO_TEST_TIMEOUT_SCALE"); s != "" {
   562  				timeoutScale, err := strconv.Atoi(s)
   563  				if err != nil {
   564  					t.Fatalf("failed to parse $GO_TEST_TIMEOUT_SCALE = %q as integer: %v", s, err)
   565  				}
   566  				tim *= timeoutScale
   567  			}
   568  		case "-goexperiment": // set GOEXPERIMENT environment
   569  			args = args[1:]
   570  			if goexp != "" {
   571  				goexp += ","
   572  			}
   573  			goexp += args[0]
   574  			runenv = append(runenv, "GOEXPERIMENT="+goexp)
   575  
   576  		case "-godebug": // set GODEBUG environment
   577  			args = args[1:]
   578  			if godebug != "" {
   579  				godebug += ","
   580  			}
   581  			godebug += args[0]
   582  			runenv = append(runenv, "GODEBUG="+godebug)
   583  
   584  		default:
   585  			flags = append(flags, args[0])
   586  		}
   587  		args = args[1:]
   588  	}
   589  	if action == "errorcheck" {
   590  		found := false
   591  		for i, f := range flags {
   592  			if strings.HasPrefix(f, "-d=") {
   593  				flags[i] = f + ",ssa/check/on"
   594  				found = true
   595  				break
   596  			}
   597  		}
   598  		if !found {
   599  			flags = append(flags, "-d=ssa/check/on")
   600  		}
   601  	}
   602  
   603  	tempDir := t.TempDir()
   604  	err = os.Mkdir(filepath.Join(tempDir, "test"), 0755)
   605  	if err != nil {
   606  		t.Fatal(err)
   607  	}
   608  
   609  	err = os.WriteFile(filepath.Join(tempDir, t.goFile), srcBytes, 0644)
   610  	if err != nil {
   611  		t.Fatal(err)
   612  	}
   613  
   614  	var (
   615  		runInDir        = tempDir
   616  		tempDirIsGOPATH = false
   617  	)
   618  	runcmd := func(args ...string) ([]byte, error) {
   619  		cmd := exec.Command(args[0], args[1:]...)
   620  		var buf bytes.Buffer
   621  		cmd.Stdout = &buf
   622  		cmd.Stderr = &buf
   623  		cmd.Env = append(os.Environ(), "GOENV=off", "GOFLAGS=")
   624  		if runInDir != "" {
   625  			cmd.Dir = runInDir
   626  			// Set PWD to match Dir to speed up os.Getwd in the child process.
   627  			cmd.Env = append(cmd.Env, "PWD="+cmd.Dir)
   628  		} else {
   629  			// Default to running in the GOROOT/test directory.
   630  			cmd.Dir = t.gorootTestDir
   631  			// Set PWD to match Dir to speed up os.Getwd in the child process.
   632  			cmd.Env = append(cmd.Env, "PWD="+cmd.Dir)
   633  		}
   634  		if tempDirIsGOPATH {
   635  			cmd.Env = append(cmd.Env, "GOPATH="+tempDir)
   636  		}
   637  		cmd.Env = append(cmd.Env, "STDLIB_IMPORTCFG="+stdlibImportcfgFile())
   638  		cmd.Env = append(cmd.Env, runenv...)
   639  
   640  		var err error
   641  
   642  		if tim != 0 {
   643  			err = cmd.Start()
   644  			// This command-timeout code adapted from cmd/go/test.go
   645  			// Note: the Go command uses a more sophisticated timeout
   646  			// strategy, first sending SIGQUIT (if appropriate for the
   647  			// OS in question) to try to trigger a stack trace, then
   648  			// finally much later SIGKILL. If timeouts prove to be a
   649  			// common problem here, it would be worth porting over
   650  			// that code as well. See https://do.dev/issue/50973
   651  			// for more discussion.
   652  			if err == nil {
   653  				tick := time.NewTimer(time.Duration(tim) * time.Second)
   654  				done := make(chan error)
   655  				go func() {
   656  					done <- cmd.Wait()
   657  				}()
   658  				select {
   659  				case err = <-done:
   660  					// ok
   661  				case <-tick.C:
   662  					cmd.Process.Signal(os.Interrupt)
   663  					time.Sleep(1 * time.Second)
   664  					cmd.Process.Kill()
   665  					<-done
   666  					err = errTimeout
   667  				}
   668  				tick.Stop()
   669  			}
   670  		} else {
   671  			err = cmd.Run()
   672  		}
   673  		if err != nil && err != errTimeout {
   674  			err = fmt.Errorf("%s\n%s", err, buf.Bytes())
   675  		}
   676  		return buf.Bytes(), err
   677  	}
   678  
   679  	importcfg := func(pkgs []*goDirPkg) string {
   680  		cfg := stdlibImportcfg()
   681  		for _, pkg := range pkgs {
   682  			pkgpath := path.Join("test", strings.TrimSuffix(pkg.files[0], ".go"))
   683  			cfg += "\npackagefile " + pkgpath + "=" + filepath.Join(tempDir, pkgpath+".a")
   684  		}
   685  		filename := filepath.Join(tempDir, "importcfg")
   686  		err := os.WriteFile(filename, []byte(cfg), 0644)
   687  		if err != nil {
   688  			t.Fatal(err)
   689  		}
   690  		return filename
   691  	}
   692  
   693  	long := filepath.Join(t.gorootTestDir, t.goFileName())
   694  	switch action {
   695  	default:
   696  		t.Fatalf("unimplemented action %q", action)
   697  		panic("unreachable")
   698  
   699  	case "asmcheck":
   700  		// Compile Go file and match the generated assembly
   701  		// against a set of regexps in comments.
   702  		ops := t.wantedAsmOpcodes(long)
   703  		self := runtime.GOOS + "/" + runtime.GOARCH
   704  		for _, env := range ops.Envs() {
   705  			// Only run checks relevant to the current GOOS/GOARCH,
   706  			// to avoid triggering a cross-compile of the runtime.
   707  			if string(env) != self && !strings.HasPrefix(string(env), self+"/") && !*allCodegen {
   708  				continue
   709  			}
   710  			// -S=2 forces outermost line numbers when disassembling inlined code.
   711  			cmdline := []string{"build", "-gcflags", "-S=2"}
   712  
   713  			// Append flags, but don't override -gcflags=-S=2; add to it instead.
   714  			for i := 0; i < len(flags); i++ {
   715  				flag := flags[i]
   716  				switch {
   717  				case strings.HasPrefix(flag, "-gcflags="):
   718  					cmdline[2] += " " + strings.TrimPrefix(flag, "-gcflags=")
   719  				case strings.HasPrefix(flag, "--gcflags="):
   720  					cmdline[2] += " " + strings.TrimPrefix(flag, "--gcflags=")
   721  				case flag == "-gcflags", flag == "--gcflags":
   722  					i++
   723  					if i < len(flags) {
   724  						cmdline[2] += " " + flags[i]
   725  					}
   726  				default:
   727  					cmdline = append(cmdline, flag)
   728  				}
   729  			}
   730  
   731  			cmdline = append(cmdline, long)
   732  			cmd := exec.Command(goTool, cmdline...)
   733  			cmd.Env = append(os.Environ(), env.Environ()...)
   734  			if len(flags) > 0 && flags[0] == "-race" {
   735  				cmd.Env = append(cmd.Env, "CGO_ENABLED=1")
   736  			}
   737  
   738  			var buf bytes.Buffer
   739  			cmd.Stdout, cmd.Stderr = &buf, &buf
   740  			if err := cmd.Run(); err != nil {
   741  				t.Log(env, "\n", cmd.Stderr)
   742  				return err
   743  			}
   744  
   745  			err := t.asmCheck(buf.String(), long, env, ops[env])
   746  			if err != nil {
   747  				return err
   748  			}
   749  		}
   750  		return nil
   751  
   752  	case "errorcheck":
   753  		// Compile Go file.
   754  		// Fail if wantError is true and compilation was successful and vice versa.
   755  		// Match errors produced by gc against errors in comments.
   756  		// TODO(gri) remove need for -C (disable printing of columns in error messages)
   757  		cmdline := []string{goTool, "tool", "compile", "-p=p", "-d=panic", "-C", "-e", "-importcfg=" + stdlibImportcfgFile(), "-o", "a.o"}
   758  		// No need to add -dynlink even if linkshared if we're just checking for errors...
   759  		cmdline = append(cmdline, flags...)
   760  		cmdline = append(cmdline, long)
   761  		out, err := runcmd(cmdline...)
   762  		if wantError {
   763  			if err == nil {
   764  				return fmt.Errorf("compilation succeeded unexpectedly\n%s", out)
   765  			}
   766  			if err == errTimeout {
   767  				return fmt.Errorf("compilation timed out")
   768  			}
   769  		} else {
   770  			if err != nil {
   771  				return err
   772  			}
   773  		}
   774  		if *updateErrors {
   775  			t.updateErrors(string(out), long)
   776  		}
   777  		return t.errorCheck(string(out), wantAuto, long, t.goFile)
   778  
   779  	case "compile":
   780  		// Compile Go file.
   781  		_, err := compileFile(runcmd, long, flags)
   782  		return err
   783  
   784  	case "compiledir":
   785  		// Compile all files in the directory as packages in lexicographic order.
   786  		longdir := filepath.Join(t.gorootTestDir, t.goDirName())
   787  		pkgs := goDirPackages(t.T, longdir, singlefilepkgs)
   788  		importcfgfile := importcfg(pkgs)
   789  
   790  		for _, pkg := range pkgs {
   791  			_, err := compileInDir(runcmd, longdir, flags, importcfgfile, pkg.name, pkg.files...)
   792  			if err != nil {
   793  				return err
   794  			}
   795  		}
   796  		return nil
   797  
   798  	case "errorcheckdir", "errorcheckandrundir":
   799  		flags = append(flags, "-d=panic")
   800  		// Compile and errorCheck all files in the directory as packages in lexicographic order.
   801  		// If errorcheckdir and wantError, compilation of the last package must fail.
   802  		// If errorcheckandrundir and wantError, compilation of the package prior the last must fail.
   803  		longdir := filepath.Join(t.gorootTestDir, t.goDirName())
   804  		pkgs := goDirPackages(t.T, longdir, singlefilepkgs)
   805  		errPkg := len(pkgs) - 1
   806  		if wantError && action == "errorcheckandrundir" {
   807  			// The last pkg should compiled successfully and will be run in next case.
   808  			// Preceding pkg must return an error from compileInDir.
   809  			errPkg--
   810  		}
   811  		importcfgfile := importcfg(pkgs)
   812  		for i, pkg := range pkgs {
   813  			out, err := compileInDir(runcmd, longdir, flags, importcfgfile, pkg.name, pkg.files...)
   814  			if i == errPkg {
   815  				if wantError && err == nil {
   816  					return fmt.Errorf("compilation succeeded unexpectedly\n%s", out)
   817  				} else if !wantError && err != nil {
   818  					return err
   819  				}
   820  			} else if err != nil {
   821  				return err
   822  			}
   823  			var fullshort []string
   824  			for _, name := range pkg.files {
   825  				fullshort = append(fullshort, filepath.Join(longdir, name), name)
   826  			}
   827  			err = t.errorCheck(string(out), wantAuto, fullshort...)
   828  			if err != nil {
   829  				return err
   830  			}
   831  		}
   832  		if action == "errorcheckdir" {
   833  			return nil
   834  		}
   835  		fallthrough
   836  
   837  	case "rundir":
   838  		// Compile all files in the directory as packages in lexicographic order.
   839  		// In case of errorcheckandrundir, ignore failed compilation of the package before the last.
   840  		// Link as if the last file is the main package, run it.
   841  		// Verify the expected output.
   842  		longdir := filepath.Join(t.gorootTestDir, t.goDirName())
   843  		pkgs := goDirPackages(t.T, longdir, singlefilepkgs)
   844  		// Split flags into gcflags and ldflags
   845  		ldflags := []string{}
   846  		for i, fl := range flags {
   847  			if fl == "-ldflags" {
   848  				ldflags = flags[i+1:]
   849  				flags = flags[0:i]
   850  				break
   851  			}
   852  		}
   853  
   854  		importcfgfile := importcfg(pkgs)
   855  
   856  		for i, pkg := range pkgs {
   857  			_, err := compileInDir(runcmd, longdir, flags, importcfgfile, pkg.name, pkg.files...)
   858  			// Allow this package compilation fail based on conditions below;
   859  			// its errors were checked in previous case.
   860  			if err != nil && !(wantError && action == "errorcheckandrundir" && i == len(pkgs)-2) {
   861  				return err
   862  			}
   863  
   864  			if i == len(pkgs)-1 {
   865  				err = linkFile(runcmd, pkg.files[0], importcfgfile, ldflags)
   866  				if err != nil {
   867  					return err
   868  				}
   869  				var cmd []string
   870  				cmd = append(cmd, findExecCmd()...)
   871  				cmd = append(cmd, filepath.Join(tempDir, "a.exe"))
   872  				cmd = append(cmd, args...)
   873  				out, err := runcmd(cmd...)
   874  				if err != nil {
   875  					return err
   876  				}
   877  				t.checkExpectedOutput(out)
   878  			}
   879  		}
   880  		return nil
   881  
   882  	case "runindir":
   883  		// Make a shallow copy of t.goDirName() in its own module and GOPATH, and
   884  		// run "go run ." in it. The module path (and hence import path prefix) of
   885  		// the copy is equal to the basename of the source directory.
   886  		//
   887  		// It's used when test a requires a full 'go build' in order to compile
   888  		// the sources, such as when importing multiple packages (issue29612.dir)
   889  		// or compiling a package containing assembly files (see issue15609.dir),
   890  		// but still needs to be run to verify the expected output.
   891  		tempDirIsGOPATH = true
   892  		srcDir := filepath.Join(t.gorootTestDir, t.goDirName())
   893  		modName := filepath.Base(srcDir)
   894  		gopathSrcDir := filepath.Join(tempDir, "src", modName)
   895  		runInDir = gopathSrcDir
   896  
   897  		if err := overlayDir(gopathSrcDir, srcDir); err != nil {
   898  			t.Fatal(err)
   899  		}
   900  
   901  		modFile := fmt.Sprintf("module %s\ngo 1.14\n", modName)
   902  		if err := os.WriteFile(filepath.Join(gopathSrcDir, "go.mod"), []byte(modFile), 0666); err != nil {
   903  			t.Fatal(err)
   904  		}
   905  
   906  		cmd := []string{goTool, "run", t.goGcflags()}
   907  		if *linkshared {
   908  			cmd = append(cmd, "-linkshared")
   909  		}
   910  		cmd = append(cmd, flags...)
   911  		cmd = append(cmd, ".")
   912  		out, err := runcmd(cmd...)
   913  		if err != nil {
   914  			return err
   915  		}
   916  		return t.checkExpectedOutput(out)
   917  
   918  	case "build":
   919  		// Build Go file.
   920  		cmd := []string{goTool, "build", t.goGcflags()}
   921  		cmd = append(cmd, flags...)
   922  		cmd = append(cmd, "-o", "a.exe", long)
   923  		_, err := runcmd(cmd...)
   924  		return err
   925  
   926  	case "builddir", "buildrundir":
   927  		// Build an executable from all the .go and .s files in a subdirectory.
   928  		// Run it and verify its output in the buildrundir case.
   929  		longdir := filepath.Join(t.gorootTestDir, t.goDirName())
   930  		files, err := os.ReadDir(longdir)
   931  		if err != nil {
   932  			t.Fatal(err)
   933  		}
   934  		var gos []string
   935  		var asms []string
   936  		for _, file := range files {
   937  			switch filepath.Ext(file.Name()) {
   938  			case ".go":
   939  				gos = append(gos, filepath.Join(longdir, file.Name()))
   940  			case ".s":
   941  				asms = append(asms, filepath.Join(longdir, file.Name()))
   942  			}
   943  
   944  		}
   945  		if len(asms) > 0 {
   946  			emptyHdrFile := filepath.Join(tempDir, "go_asm.h")
   947  			if err := os.WriteFile(emptyHdrFile, nil, 0666); err != nil {
   948  				t.Fatalf("write empty go_asm.h: %v", err)
   949  			}
   950  			cmd := []string{goTool, "tool", "asm", "-p=main", "-gensymabis", "-o", "symabis"}
   951  			cmd = append(cmd, asms...)
   952  			_, err = runcmd(cmd...)
   953  			if err != nil {
   954  				return err
   955  			}
   956  		}
   957  		var objs []string
   958  		cmd := []string{goTool, "tool", "compile", "-p=main", "-e", "-D", ".", "-importcfg=" + stdlibImportcfgFile(), "-o", "go.o"}
   959  		if len(asms) > 0 {
   960  			cmd = append(cmd, "-asmhdr", "go_asm.h", "-symabis", "symabis")
   961  		}
   962  		cmd = append(cmd, gos...)
   963  		_, err = runcmd(cmd...)
   964  		if err != nil {
   965  			return err
   966  		}
   967  		objs = append(objs, "go.o")
   968  		if len(asms) > 0 {
   969  			cmd = []string{goTool, "tool", "asm", "-p=main", "-e", "-I", ".", "-o", "asm.o"}
   970  			cmd = append(cmd, asms...)
   971  			_, err = runcmd(cmd...)
   972  			if err != nil {
   973  				return err
   974  			}
   975  			objs = append(objs, "asm.o")
   976  		}
   977  		cmd = []string{goTool, "tool", "pack", "c", "all.a"}
   978  		cmd = append(cmd, objs...)
   979  		_, err = runcmd(cmd...)
   980  		if err != nil {
   981  			return err
   982  		}
   983  		cmd = []string{goTool, "tool", "link", "-importcfg=" + stdlibImportcfgFile(), "-o", "a.exe", "all.a"}
   984  		_, err = runcmd(cmd...)
   985  		if err != nil {
   986  			return err
   987  		}
   988  
   989  		if action == "builddir" {
   990  			return nil
   991  		}
   992  		cmd = append(findExecCmd(), filepath.Join(tempDir, "a.exe"))
   993  		out, err := runcmd(cmd...)
   994  		if err != nil {
   995  			return err
   996  		}
   997  		return t.checkExpectedOutput(out)
   998  
   999  	case "buildrun":
  1000  		// Build an executable from Go file, then run it, verify its output.
  1001  		// Useful for timeout tests where failure mode is infinite loop.
  1002  		// TODO: not supported on NaCl
  1003  		cmd := []string{goTool, "build", t.goGcflags(), "-o", "a.exe"}
  1004  		if *linkshared {
  1005  			cmd = append(cmd, "-linkshared")
  1006  		}
  1007  		longDirGoFile := filepath.Join(filepath.Join(t.gorootTestDir, t.dir), t.goFile)
  1008  		cmd = append(cmd, flags...)
  1009  		cmd = append(cmd, longDirGoFile)
  1010  		_, err := runcmd(cmd...)
  1011  		if err != nil {
  1012  			return err
  1013  		}
  1014  		cmd = []string{"./a.exe"}
  1015  		out, err := runcmd(append(cmd, args...)...)
  1016  		if err != nil {
  1017  			return err
  1018  		}
  1019  
  1020  		return t.checkExpectedOutput(out)
  1021  
  1022  	case "run":
  1023  		// Run Go file if no special go command flags are provided;
  1024  		// otherwise build an executable and run it.
  1025  		// Verify the output.
  1026  		runInDir = ""
  1027  		var out []byte
  1028  		var err error
  1029  		if len(flags)+len(args) == 0 && t.goGcflagsIsEmpty() && !*linkshared && goarch == runtime.GOARCH && goos == runtime.GOOS && goexp == goExperiment && godebug == goDebug {
  1030  			// If we're not using special go command flags,
  1031  			// skip all the go command machinery.
  1032  			// This avoids any time the go command would
  1033  			// spend checking whether, for example, the installed
  1034  			// package runtime is up to date.
  1035  			// Because we run lots of trivial test programs,
  1036  			// the time adds up.
  1037  			pkg := filepath.Join(tempDir, "pkg.a")
  1038  			if _, err := runcmd(goTool, "tool", "compile", "-p=main", "-importcfg="+stdlibImportcfgFile(), "-o", pkg, t.goFileName()); err != nil {
  1039  				return err
  1040  			}
  1041  			exe := filepath.Join(tempDir, "test.exe")
  1042  			cmd := []string{goTool, "tool", "link", "-s", "-w", "-importcfg=" + stdlibImportcfgFile()}
  1043  			cmd = append(cmd, "-o", exe, pkg)
  1044  			if _, err := runcmd(cmd...); err != nil {
  1045  				return err
  1046  			}
  1047  			out, err = runcmd(append([]string{exe}, args...)...)
  1048  		} else {
  1049  			cmd := []string{goTool, "run", t.goGcflags()}
  1050  			if *linkshared {
  1051  				cmd = append(cmd, "-linkshared")
  1052  			}
  1053  			cmd = append(cmd, flags...)
  1054  			cmd = append(cmd, t.goFileName())
  1055  			out, err = runcmd(append(cmd, args...)...)
  1056  		}
  1057  		if err != nil {
  1058  			return err
  1059  		}
  1060  		return t.checkExpectedOutput(out)
  1061  
  1062  	case "runoutput":
  1063  		// Run Go file and write its output into temporary Go file.
  1064  		// Run generated Go file and verify its output.
  1065  		t.runoutputGate <- true
  1066  		defer func() {
  1067  			<-t.runoutputGate
  1068  		}()
  1069  		runInDir = ""
  1070  		cmd := []string{goTool, "run", t.goGcflags()}
  1071  		if *linkshared {
  1072  			cmd = append(cmd, "-linkshared")
  1073  		}
  1074  		cmd = append(cmd, t.goFileName())
  1075  		out, err := runcmd(append(cmd, args...)...)
  1076  		if err != nil {
  1077  			return err
  1078  		}
  1079  		tfile := filepath.Join(tempDir, "tmp__.go")
  1080  		if err := os.WriteFile(tfile, out, 0666); err != nil {
  1081  			t.Fatalf("write tempfile: %v", err)
  1082  		}
  1083  		cmd = []string{goTool, "run", t.goGcflags()}
  1084  		if *linkshared {
  1085  			cmd = append(cmd, "-linkshared")
  1086  		}
  1087  		cmd = append(cmd, tfile)
  1088  		out, err = runcmd(cmd...)
  1089  		if err != nil {
  1090  			return err
  1091  		}
  1092  		return t.checkExpectedOutput(out)
  1093  
  1094  	case "errorcheckoutput":
  1095  		// Run Go file and write its output into temporary Go file.
  1096  		// Compile and errorCheck generated Go file.
  1097  		runInDir = ""
  1098  		cmd := []string{goTool, "run", t.goGcflags()}
  1099  		if *linkshared {
  1100  			cmd = append(cmd, "-linkshared")
  1101  		}
  1102  		cmd = append(cmd, t.goFileName())
  1103  		out, err := runcmd(append(cmd, args...)...)
  1104  		if err != nil {
  1105  			return err
  1106  		}
  1107  		tfile := filepath.Join(tempDir, "tmp__.go")
  1108  		err = os.WriteFile(tfile, out, 0666)
  1109  		if err != nil {
  1110  			t.Fatalf("write tempfile: %v", err)
  1111  		}
  1112  		cmdline := []string{goTool, "tool", "compile", "-importcfg=" + stdlibImportcfgFile(), "-p=p", "-d=panic", "-e", "-o", "a.o"}
  1113  		cmdline = append(cmdline, flags...)
  1114  		cmdline = append(cmdline, tfile)
  1115  		out, err = runcmd(cmdline...)
  1116  		if wantError {
  1117  			if err == nil {
  1118  				return fmt.Errorf("compilation succeeded unexpectedly\n%s", out)
  1119  			}
  1120  		} else {
  1121  			if err != nil {
  1122  				return err
  1123  			}
  1124  		}
  1125  		return t.errorCheck(string(out), false, tfile, "tmp__.go")
  1126  	}
  1127  }
  1128  
  1129  var execCmdOnce sync.Once
  1130  var execCmd []string
  1131  
  1132  func findExecCmd() []string {
  1133  	execCmdOnce.Do(func() {
  1134  		if goos == runtime.GOOS && goarch == runtime.GOARCH {
  1135  			// Do nothing.
  1136  		} else if path, err := exec.LookPath(fmt.Sprintf("go_%s_%s_exec", goos, goarch)); err == nil {
  1137  			execCmd = []string{path}
  1138  		}
  1139  	})
  1140  	return execCmd
  1141  }
  1142  
  1143  // checkExpectedOutput compares the output from compiling and/or running with the contents
  1144  // of the corresponding reference output file, if any (replace ".go" with ".out").
  1145  // If they don't match, fail with an informative message.
  1146  func (t test) checkExpectedOutput(gotBytes []byte) error {
  1147  	got := string(gotBytes)
  1148  	filename := filepath.Join(t.dir, t.goFile)
  1149  	filename = filename[:len(filename)-len(".go")]
  1150  	filename += ".out"
  1151  	b, err := os.ReadFile(filepath.Join(t.gorootTestDir, filename))
  1152  	if errors.Is(err, fs.ErrNotExist) {
  1153  		// File is allowed to be missing, in which case output should be empty.
  1154  		b = nil
  1155  	} else if err != nil {
  1156  		return err
  1157  	}
  1158  	got = strings.Replace(got, "\r\n", "\n", -1)
  1159  	if got != string(b) {
  1160  		if err == nil {
  1161  			return fmt.Errorf("output does not match expected in %s. Instead saw\n%s", filename, got)
  1162  		} else {
  1163  			return fmt.Errorf("output should be empty when (optional) expected-output file %s is not present. Instead saw\n%s", filename, got)
  1164  		}
  1165  	}
  1166  	return nil
  1167  }
  1168  
  1169  func splitOutput(out string, wantAuto bool) []string {
  1170  	// gc error messages continue onto additional lines with leading tabs.
  1171  	// Split the output at the beginning of each line that doesn't begin with a tab.
  1172  	// <autogenerated> lines are impossible to match so those are filtered out.
  1173  	var res []string
  1174  	for _, line := range strings.Split(out, "\n") {
  1175  		if strings.HasSuffix(line, "\r") { // remove '\r', output by compiler on windows
  1176  			line = line[:len(line)-1]
  1177  		}
  1178  		if strings.HasPrefix(line, "\t") {
  1179  			res[len(res)-1] += "\n" + line
  1180  		} else if strings.HasPrefix(line, "go tool") || strings.HasPrefix(line, "#") || !wantAuto && strings.HasPrefix(line, "<autogenerated>") {
  1181  			continue
  1182  		} else if strings.TrimSpace(line) != "" {
  1183  			res = append(res, line)
  1184  		}
  1185  	}
  1186  	return res
  1187  }
  1188  
  1189  // errorCheck matches errors in outStr against comments in source files.
  1190  // For each line of the source files which should generate an error,
  1191  // there should be a comment of the form // ERROR "regexp".
  1192  // If outStr has an error for a line which has no such comment,
  1193  // this function will report an error.
  1194  // Likewise if outStr does not have an error for a line which has a comment,
  1195  // or if the error message does not match the <regexp>.
  1196  // The <regexp> syntax is Perl but it's best to stick to egrep.
  1197  //
  1198  // Sources files are supplied as fullshort slice.
  1199  // It consists of pairs: full path to source file and its base name.
  1200  func (t test) errorCheck(outStr string, wantAuto bool, fullshort ...string) (err error) {
  1201  	defer func() {
  1202  		if testing.Verbose() && err != nil {
  1203  			t.Logf("gc output:\n%s", outStr)
  1204  		}
  1205  	}()
  1206  	var errs []error
  1207  	out := splitOutput(outStr, wantAuto)
  1208  
  1209  	// Cut directory name.
  1210  	for i := range out {
  1211  		for j := 0; j < len(fullshort); j += 2 {
  1212  			full, short := fullshort[j], fullshort[j+1]
  1213  			out[i] = strings.Replace(out[i], full, short, -1)
  1214  		}
  1215  	}
  1216  
  1217  	var want []wantedError
  1218  	for j := 0; j < len(fullshort); j += 2 {
  1219  		full, short := fullshort[j], fullshort[j+1]
  1220  		want = append(want, t.wantedErrors(full, short)...)
  1221  	}
  1222  
  1223  	for _, we := range want {
  1224  		var errmsgs []string
  1225  		if we.auto {
  1226  			errmsgs, out = partitionStrings("<autogenerated>", out)
  1227  		} else {
  1228  			errmsgs, out = partitionStrings(we.prefix, out)
  1229  		}
  1230  		if len(errmsgs) == 0 {
  1231  			errs = append(errs, fmt.Errorf("%s:%d: missing error %q", we.file, we.lineNum, we.reStr))
  1232  			continue
  1233  		}
  1234  		matched := false
  1235  		n := len(out)
  1236  		for _, errmsg := range errmsgs {
  1237  			// Assume errmsg says "file:line: foo".
  1238  			// Cut leading "file:line: " to avoid accidental matching of file name instead of message.
  1239  			text := errmsg
  1240  			if _, suffix, ok := strings.Cut(text, " "); ok {
  1241  				text = suffix
  1242  			}
  1243  			if we.re.MatchString(text) {
  1244  				matched = true
  1245  			} else {
  1246  				out = append(out, errmsg)
  1247  			}
  1248  		}
  1249  		if !matched {
  1250  			errs = append(errs, fmt.Errorf("%s:%d: no match for %#q in:\n\t%s", we.file, we.lineNum, we.reStr, strings.Join(out[n:], "\n\t")))
  1251  			continue
  1252  		}
  1253  	}
  1254  
  1255  	if len(out) > 0 {
  1256  		errs = append(errs, fmt.Errorf("Unmatched Errors:"))
  1257  		for _, errLine := range out {
  1258  			errs = append(errs, fmt.Errorf("%s", errLine))
  1259  		}
  1260  	}
  1261  
  1262  	if len(errs) == 0 {
  1263  		return nil
  1264  	}
  1265  	if len(errs) == 1 {
  1266  		return errs[0]
  1267  	}
  1268  	var buf bytes.Buffer
  1269  	fmt.Fprintf(&buf, "\n")
  1270  	for _, err := range errs {
  1271  		fmt.Fprintf(&buf, "%s\n", err.Error())
  1272  	}
  1273  	return errors.New(buf.String())
  1274  }
  1275  
  1276  func (test) updateErrors(out, file string) {
  1277  	base := path.Base(file)
  1278  	// Read in source file.
  1279  	src, err := os.ReadFile(file)
  1280  	if err != nil {
  1281  		fmt.Fprintln(os.Stderr, err)
  1282  		return
  1283  	}
  1284  	lines := strings.Split(string(src), "\n")
  1285  	// Remove old errors.
  1286  	for i := range lines {
  1287  		lines[i], _, _ = strings.Cut(lines[i], " // ERROR ")
  1288  	}
  1289  	// Parse new errors.
  1290  	errors := make(map[int]map[string]bool)
  1291  	tmpRe := regexp.MustCompile(`autotmp_\d+`)
  1292  	for _, errStr := range splitOutput(out, false) {
  1293  		errFile, rest, ok := strings.Cut(errStr, ":")
  1294  		if !ok || errFile != file {
  1295  			continue
  1296  		}
  1297  		lineStr, msg, ok := strings.Cut(rest, ":")
  1298  		if !ok {
  1299  			continue
  1300  		}
  1301  		line, err := strconv.Atoi(lineStr)
  1302  		line--
  1303  		if err != nil || line < 0 || line >= len(lines) {
  1304  			continue
  1305  		}
  1306  		msg = strings.Replace(msg, file, base, -1) // normalize file mentions in error itself
  1307  		msg = strings.TrimLeft(msg, " \t")
  1308  		for _, r := range []string{`\`, `*`, `+`, `?`, `[`, `]`, `(`, `)`} {
  1309  			msg = strings.Replace(msg, r, `\`+r, -1)
  1310  		}
  1311  		msg = strings.Replace(msg, `"`, `.`, -1)
  1312  		msg = tmpRe.ReplaceAllLiteralString(msg, `autotmp_[0-9]+`)
  1313  		if errors[line] == nil {
  1314  			errors[line] = make(map[string]bool)
  1315  		}
  1316  		errors[line][msg] = true
  1317  	}
  1318  	// Add new errors.
  1319  	for line, errs := range errors {
  1320  		var sorted []string
  1321  		for e := range errs {
  1322  			sorted = append(sorted, e)
  1323  		}
  1324  		sort.Strings(sorted)
  1325  		lines[line] += " // ERROR"
  1326  		for _, e := range sorted {
  1327  			lines[line] += fmt.Sprintf(` "%s$"`, e)
  1328  		}
  1329  	}
  1330  	// Write new file.
  1331  	err = os.WriteFile(file, []byte(strings.Join(lines, "\n")), 0640)
  1332  	if err != nil {
  1333  		fmt.Fprintln(os.Stderr, err)
  1334  		return
  1335  	}
  1336  	// Polish.
  1337  	exec.Command(goTool, "fmt", file).CombinedOutput()
  1338  }
  1339  
  1340  // matchPrefix reports whether s is of the form ^(.*/)?prefix(:|[),
  1341  // That is, it needs the file name prefix followed by a : or a [,
  1342  // and possibly preceded by a directory name.
  1343  func matchPrefix(s, prefix string) bool {
  1344  	i := strings.Index(s, ":")
  1345  	if i < 0 {
  1346  		return false
  1347  	}
  1348  	j := strings.LastIndex(s[:i], "/")
  1349  	s = s[j+1:]
  1350  	if len(s) <= len(prefix) || s[:len(prefix)] != prefix {
  1351  		return false
  1352  	}
  1353  	switch s[len(prefix)] {
  1354  	case '[', ':':
  1355  		return true
  1356  	}
  1357  	return false
  1358  }
  1359  
  1360  func partitionStrings(prefix string, strs []string) (matched, unmatched []string) {
  1361  	for _, s := range strs {
  1362  		if matchPrefix(s, prefix) {
  1363  			matched = append(matched, s)
  1364  		} else {
  1365  			unmatched = append(unmatched, s)
  1366  		}
  1367  	}
  1368  	return
  1369  }
  1370  
  1371  type wantedError struct {
  1372  	reStr   string
  1373  	re      *regexp.Regexp
  1374  	lineNum int
  1375  	auto    bool // match <autogenerated> line
  1376  	file    string
  1377  	prefix  string
  1378  }
  1379  
  1380  var (
  1381  	errRx       = regexp.MustCompile(`// (?:GC_)?ERROR (.*)`)
  1382  	errAutoRx   = regexp.MustCompile(`// (?:GC_)?ERRORAUTO (.*)`)
  1383  	errQuotesRx = regexp.MustCompile(`"([^"]*)"`)
  1384  	lineRx      = regexp.MustCompile(`LINE(([+-])(\d+))?`)
  1385  )
  1386  
  1387  func (t test) wantedErrors(file, short string) (errs []wantedError) {
  1388  	cache := make(map[string]*regexp.Regexp)
  1389  
  1390  	src, _ := os.ReadFile(file)
  1391  	for i, line := range strings.Split(string(src), "\n") {
  1392  		lineNum := i + 1
  1393  		if strings.Contains(line, "////") {
  1394  			// double comment disables ERROR
  1395  			continue
  1396  		}
  1397  		var auto bool
  1398  		m := errAutoRx.FindStringSubmatch(line)
  1399  		if m != nil {
  1400  			auto = true
  1401  		} else {
  1402  			m = errRx.FindStringSubmatch(line)
  1403  		}
  1404  		if m == nil {
  1405  			continue
  1406  		}
  1407  		all := m[1]
  1408  		mm := errQuotesRx.FindAllStringSubmatch(all, -1)
  1409  		if mm == nil {
  1410  			t.Fatalf("%s:%d: invalid errchk line: %s", t.goFileName(), lineNum, line)
  1411  		}
  1412  		for _, m := range mm {
  1413  			rx := lineRx.ReplaceAllStringFunc(m[1], func(m string) string {
  1414  				n := lineNum
  1415  				if strings.HasPrefix(m, "LINE+") {
  1416  					delta, _ := strconv.Atoi(m[5:])
  1417  					n += delta
  1418  				} else if strings.HasPrefix(m, "LINE-") {
  1419  					delta, _ := strconv.Atoi(m[5:])
  1420  					n -= delta
  1421  				}
  1422  				return fmt.Sprintf("%s:%d", short, n)
  1423  			})
  1424  			re := cache[rx]
  1425  			if re == nil {
  1426  				var err error
  1427  				re, err = regexp.Compile(rx)
  1428  				if err != nil {
  1429  					t.Fatalf("%s:%d: invalid regexp \"%s\" in ERROR line: %v", t.goFileName(), lineNum, rx, err)
  1430  				}
  1431  				cache[rx] = re
  1432  			}
  1433  			prefix := fmt.Sprintf("%s:%d", short, lineNum)
  1434  			errs = append(errs, wantedError{
  1435  				reStr:   rx,
  1436  				re:      re,
  1437  				prefix:  prefix,
  1438  				auto:    auto,
  1439  				lineNum: lineNum,
  1440  				file:    short,
  1441  			})
  1442  		}
  1443  	}
  1444  
  1445  	return
  1446  }
  1447  
  1448  const (
  1449  	// Regexp to match a single opcode check: optionally begin with "-" (to indicate
  1450  	// a negative check), followed by a string literal enclosed in "" or ``. For "",
  1451  	// backslashes must be handled.
  1452  	reMatchCheck = `-?(?:\x60[^\x60]*\x60|"(?:[^"\\]|\\.)*")`
  1453  )
  1454  
  1455  var (
  1456  	// Regexp to split a line in code and comment, trimming spaces
  1457  	rxAsmComment = regexp.MustCompile(`^\s*(.*?)\s*(?://\s*(.+)\s*)?$`)
  1458  
  1459  	// Regexp to extract an architecture check: architecture name (or triplet),
  1460  	// followed by semi-colon, followed by a comma-separated list of opcode checks.
  1461  	// Extraneous spaces are ignored.
  1462  	//
  1463  	// An example: arm64/v8.1 : -`ADD` , `SUB`
  1464  	//	"(\w+)" matches "arm64" (architecture name)
  1465  	//	"(/[\w.]+)?" matches "v8.1" (architecture version)
  1466  	//	"(/\w*)?" doesn't match anything here (it's an optional part of the triplet)
  1467  	//	"\s*:\s*" matches " : " (semi-colon)
  1468  	//	"(" starts a capturing group
  1469  	//      first reMatchCheck matches "-`ADD`"
  1470  	//	`(?:" starts a non-capturing group
  1471  	//	"\s*,\s*` matches " , "
  1472  	//	second reMatchCheck matches "`SUB`"
  1473  	//	")*)" closes started groups; "*" means that there might be other elements in the comma-separated list
  1474  	rxAsmPlatform = regexp.MustCompile(`(\w+)(/[\w.]+)?(/\w*)?\s*:\s*(` + reMatchCheck + `(?:\s*,\s*` + reMatchCheck + `)*)`)
  1475  
  1476  	// Regexp to extract a single opcoded check
  1477  	rxAsmCheck = regexp.MustCompile(reMatchCheck)
  1478  
  1479  	// List of all architecture variants. Key is the GOARCH architecture,
  1480  	// value[0] is the variant-changing environment variable, and values[1:]
  1481  	// are the supported variants.
  1482  	archVariants = map[string][]string{
  1483  		"386":     {"GO386", "sse2", "softfloat"},
  1484  		"amd64":   {"GOAMD64", "v1", "v2", "v3", "v4"},
  1485  		"arm":     {"GOARM", "5", "6", "7", "7,softfloat"},
  1486  		"arm64":   {"GOARM64", "v8.0", "v8.1"},
  1487  		"loong64": {},
  1488  		"mips":    {"GOMIPS", "hardfloat", "softfloat"},
  1489  		"mips64":  {"GOMIPS64", "hardfloat", "softfloat"},
  1490  		"ppc64":   {"GOPPC64", "power8", "power9", "power10"},
  1491  		"ppc64le": {"GOPPC64", "power8", "power9", "power10"},
  1492  		"ppc64x":  {}, // A pseudo-arch representing both ppc64 and ppc64le
  1493  		"s390x":   {},
  1494  		"wasm":    {},
  1495  		"riscv64": {"GORISCV64", "rva20u64", "rva22u64"},
  1496  	}
  1497  )
  1498  
  1499  // wantedAsmOpcode is a single asmcheck check
  1500  type wantedAsmOpcode struct {
  1501  	fileline string         // original source file/line (eg: "/path/foo.go:45")
  1502  	line     int            // original source line
  1503  	opcode   *regexp.Regexp // opcode check to be performed on assembly output
  1504  	negative bool           // true if the check is supposed to fail rather than pass
  1505  	found    bool           // true if the opcode check matched at least one in the output
  1506  }
  1507  
  1508  // A build environment triplet separated by slashes (eg: linux/386/sse2).
  1509  // The third field can be empty if the arch does not support variants (eg: "plan9/amd64/")
  1510  type buildEnv string
  1511  
  1512  // Environ returns the environment it represents in cmd.Environ() "key=val" format
  1513  // For instance, "linux/386/sse2".Environ() returns {"GOOS=linux", "GOARCH=386", "GO386=sse2"}
  1514  func (b buildEnv) Environ() []string {
  1515  	fields := strings.Split(string(b), "/")
  1516  	if len(fields) != 3 {
  1517  		panic("invalid buildEnv string: " + string(b))
  1518  	}
  1519  	env := []string{"GOOS=" + fields[0], "GOARCH=" + fields[1]}
  1520  	if fields[2] != "" {
  1521  		env = append(env, archVariants[fields[1]][0]+"="+fields[2])
  1522  	}
  1523  	return env
  1524  }
  1525  
  1526  // asmChecks represents all the asmcheck checks present in a test file
  1527  // The outer map key is the build triplet in which the checks must be performed.
  1528  // The inner map key represent the source file line ("filename.go:1234") at which the
  1529  // checks must be performed.
  1530  type asmChecks map[buildEnv]map[string][]wantedAsmOpcode
  1531  
  1532  // Envs returns all the buildEnv in which at least one check is present
  1533  func (a asmChecks) Envs() []buildEnv {
  1534  	var envs []buildEnv
  1535  	for e := range a {
  1536  		envs = append(envs, e)
  1537  	}
  1538  	sort.Slice(envs, func(i, j int) bool {
  1539  		return string(envs[i]) < string(envs[j])
  1540  	})
  1541  	return envs
  1542  }
  1543  
  1544  func (t test) wantedAsmOpcodes(fn string) asmChecks {
  1545  	ops := make(asmChecks)
  1546  
  1547  	comment := ""
  1548  	src, err := os.ReadFile(fn)
  1549  	if err != nil {
  1550  		t.Fatal(err)
  1551  	}
  1552  	for i, line := range strings.Split(string(src), "\n") {
  1553  		matches := rxAsmComment.FindStringSubmatch(line)
  1554  		code, cmt := matches[1], matches[2]
  1555  
  1556  		// Keep comments pending in the comment variable until
  1557  		// we find a line that contains some code.
  1558  		comment += " " + cmt
  1559  		if code == "" {
  1560  			continue
  1561  		}
  1562  
  1563  		// Parse and extract any architecture check from comments,
  1564  		// made by one architecture name and multiple checks.
  1565  		lnum := fn + ":" + strconv.Itoa(i+1)
  1566  		for _, ac := range rxAsmPlatform.FindAllStringSubmatch(comment, -1) {
  1567  			archspec, allchecks := ac[1:4], ac[4]
  1568  
  1569  			var arch, subarch, os string
  1570  			switch {
  1571  			case archspec[2] != "": // 3 components: "linux/386/sse2"
  1572  				os, arch, subarch = archspec[0], archspec[1][1:], archspec[2][1:]
  1573  			case archspec[1] != "": // 2 components: "386/sse2"
  1574  				os, arch, subarch = "linux", archspec[0], archspec[1][1:]
  1575  			default: // 1 component: "386"
  1576  				os, arch, subarch = "linux", archspec[0], ""
  1577  				if arch == "wasm" {
  1578  					os = "js"
  1579  				}
  1580  			}
  1581  
  1582  			if _, ok := archVariants[arch]; !ok {
  1583  				t.Fatalf("%s:%d: unsupported architecture: %v", t.goFileName(), i+1, arch)
  1584  			}
  1585  
  1586  			// Create the build environments corresponding the above specifiers
  1587  			envs := make([]buildEnv, 0, 4)
  1588  			arches := []string{arch}
  1589  			// ppc64x is a pseudo-arch, generate tests for both endian variants.
  1590  			if arch == "ppc64x" {
  1591  				arches = []string{"ppc64", "ppc64le"}
  1592  			}
  1593  			for _, arch := range arches {
  1594  				if subarch != "" {
  1595  					envs = append(envs, buildEnv(os+"/"+arch+"/"+subarch))
  1596  				} else {
  1597  					subarchs := archVariants[arch]
  1598  					if len(subarchs) == 0 {
  1599  						envs = append(envs, buildEnv(os+"/"+arch+"/"))
  1600  					} else {
  1601  						for _, sa := range archVariants[arch][1:] {
  1602  							envs = append(envs, buildEnv(os+"/"+arch+"/"+sa))
  1603  						}
  1604  					}
  1605  				}
  1606  			}
  1607  
  1608  			for _, m := range rxAsmCheck.FindAllString(allchecks, -1) {
  1609  				negative := false
  1610  				if m[0] == '-' {
  1611  					negative = true
  1612  					m = m[1:]
  1613  				}
  1614  
  1615  				rxsrc, err := strconv.Unquote(m)
  1616  				if err != nil {
  1617  					t.Fatalf("%s:%d: error unquoting string: %v", t.goFileName(), i+1, err)
  1618  				}
  1619  
  1620  				// Compile the checks as regular expressions. Notice that we
  1621  				// consider checks as matching from the beginning of the actual
  1622  				// assembler source (that is, what is left on each line of the
  1623  				// compile -S output after we strip file/line info) to avoid
  1624  				// trivial bugs such as "ADD" matching "FADD". This
  1625  				// doesn't remove genericity: it's still possible to write
  1626  				// something like "F?ADD", but we make common cases simpler
  1627  				// to get right.
  1628  				oprx, err := regexp.Compile("^" + rxsrc)
  1629  				if err != nil {
  1630  					t.Fatalf("%s:%d: %v", t.goFileName(), i+1, err)
  1631  				}
  1632  
  1633  				for _, env := range envs {
  1634  					if ops[env] == nil {
  1635  						ops[env] = make(map[string][]wantedAsmOpcode)
  1636  					}
  1637  					ops[env][lnum] = append(ops[env][lnum], wantedAsmOpcode{
  1638  						negative: negative,
  1639  						fileline: lnum,
  1640  						line:     i + 1,
  1641  						opcode:   oprx,
  1642  					})
  1643  				}
  1644  			}
  1645  		}
  1646  		comment = ""
  1647  	}
  1648  
  1649  	return ops
  1650  }
  1651  
  1652  func (t test) asmCheck(outStr string, fn string, env buildEnv, fullops map[string][]wantedAsmOpcode) error {
  1653  	// The assembly output contains the concatenated dump of multiple functions.
  1654  	// the first line of each function begins at column 0, while the rest is
  1655  	// indented by a tabulation. These data structures help us index the
  1656  	// output by function.
  1657  	functionMarkers := make([]int, 1)
  1658  	lineFuncMap := make(map[string]int)
  1659  
  1660  	lines := strings.Split(outStr, "\n")
  1661  	rxLine := regexp.MustCompile(fmt.Sprintf(`\((%s:\d+)\)\s+(.*)`, regexp.QuoteMeta(fn)))
  1662  
  1663  	for nl, line := range lines {
  1664  		// Check if this line begins a function
  1665  		if len(line) > 0 && line[0] != '\t' {
  1666  			functionMarkers = append(functionMarkers, nl)
  1667  		}
  1668  
  1669  		// Search if this line contains a assembly opcode (which is prefixed by the
  1670  		// original source file/line in parenthesis)
  1671  		matches := rxLine.FindStringSubmatch(line)
  1672  		if len(matches) == 0 {
  1673  			continue
  1674  		}
  1675  		srcFileLine, asm := matches[1], matches[2]
  1676  
  1677  		// Associate the original file/line information to the current
  1678  		// function in the output; it will be useful to dump it in case
  1679  		// of error.
  1680  		lineFuncMap[srcFileLine] = len(functionMarkers) - 1
  1681  
  1682  		// If there are opcode checks associated to this source file/line,
  1683  		// run the checks.
  1684  		if ops, found := fullops[srcFileLine]; found {
  1685  			for i := range ops {
  1686  				if !ops[i].found && ops[i].opcode.FindString(asm) != "" {
  1687  					ops[i].found = true
  1688  				}
  1689  			}
  1690  		}
  1691  	}
  1692  	functionMarkers = append(functionMarkers, len(lines))
  1693  
  1694  	var failed []wantedAsmOpcode
  1695  	for _, ops := range fullops {
  1696  		for _, o := range ops {
  1697  			// There's a failure if a negative match was found,
  1698  			// or a positive match was not found.
  1699  			if o.negative == o.found {
  1700  				failed = append(failed, o)
  1701  			}
  1702  		}
  1703  	}
  1704  	if len(failed) == 0 {
  1705  		return nil
  1706  	}
  1707  
  1708  	// At least one asmcheck failed; report them.
  1709  	lastFunction := -1
  1710  	var errbuf bytes.Buffer
  1711  	fmt.Fprintln(&errbuf)
  1712  	sort.Slice(failed, func(i, j int) bool { return failed[i].line < failed[j].line })
  1713  	for _, o := range failed {
  1714  		// Dump the function in which this opcode check was supposed to
  1715  		// pass but failed.
  1716  		funcIdx := lineFuncMap[o.fileline]
  1717  		if funcIdx != 0 && funcIdx != lastFunction {
  1718  			funcLines := lines[functionMarkers[funcIdx]:functionMarkers[funcIdx+1]]
  1719  			t.Log(strings.Join(funcLines, "\n"))
  1720  			lastFunction = funcIdx // avoid printing same function twice
  1721  		}
  1722  
  1723  		if o.negative {
  1724  			fmt.Fprintf(&errbuf, "%s:%d: %s: wrong opcode found: %q\n", t.goFileName(), o.line, env, o.opcode.String())
  1725  		} else {
  1726  			fmt.Fprintf(&errbuf, "%s:%d: %s: opcode not found: %q\n", t.goFileName(), o.line, env, o.opcode.String())
  1727  		}
  1728  	}
  1729  	return errors.New(errbuf.String())
  1730  }
  1731  
  1732  // defaultRunOutputLimit returns the number of runoutput tests that
  1733  // can be executed in parallel.
  1734  func defaultRunOutputLimit() int {
  1735  	const maxArmCPU = 2
  1736  
  1737  	cpu := runtime.NumCPU()
  1738  	if runtime.GOARCH == "arm" && cpu > maxArmCPU {
  1739  		cpu = maxArmCPU
  1740  	}
  1741  	return cpu
  1742  }
  1743  
  1744  func TestShouldTest(t *testing.T) {
  1745  	if *shard != 0 {
  1746  		t.Skipf("nothing to test on shard index %d", *shard)
  1747  	}
  1748  
  1749  	assert := func(ok bool, _ string) {
  1750  		t.Helper()
  1751  		if !ok {
  1752  			t.Error("test case failed")
  1753  		}
  1754  	}
  1755  	assertNot := func(ok bool, _ string) { t.Helper(); assert(!ok, "") }
  1756  
  1757  	// Simple tests.
  1758  	assert(shouldTest("// +build linux", "linux", "arm"))
  1759  	assert(shouldTest("// +build !windows", "linux", "arm"))
  1760  	assertNot(shouldTest("// +build !windows", "windows", "amd64"))
  1761  
  1762  	// A file with no build tags will always be tested.
  1763  	assert(shouldTest("// This is a test.", "os", "arch"))
  1764  
  1765  	// Build tags separated by a space are OR-ed together.
  1766  	assertNot(shouldTest("// +build arm 386", "linux", "amd64"))
  1767  
  1768  	// Build tags separated by a comma are AND-ed together.
  1769  	assertNot(shouldTest("// +build !windows,!plan9", "windows", "amd64"))
  1770  	assertNot(shouldTest("// +build !windows,!plan9", "plan9", "386"))
  1771  
  1772  	// Build tags on multiple lines are AND-ed together.
  1773  	assert(shouldTest("// +build !windows\n// +build amd64", "linux", "amd64"))
  1774  	assertNot(shouldTest("// +build !windows\n// +build amd64", "windows", "amd64"))
  1775  
  1776  	// Test that (!a OR !b) matches anything.
  1777  	assert(shouldTest("// +build !windows !plan9", "windows", "amd64"))
  1778  
  1779  	// Test that //go:build tag match.
  1780  	assert(shouldTest("//go:build go1.4", "linux", "amd64"))
  1781  }
  1782  
  1783  // overlayDir makes a minimal-overhead copy of srcRoot in which new files may be added.
  1784  func overlayDir(dstRoot, srcRoot string) error {
  1785  	dstRoot = filepath.Clean(dstRoot)
  1786  	if err := os.MkdirAll(dstRoot, 0777); err != nil {
  1787  		return err
  1788  	}
  1789  
  1790  	srcRoot, err := filepath.Abs(srcRoot)
  1791  	if err != nil {
  1792  		return err
  1793  	}
  1794  
  1795  	return filepath.WalkDir(srcRoot, func(srcPath string, d fs.DirEntry, err error) error {
  1796  		if err != nil || srcPath == srcRoot {
  1797  			return err
  1798  		}
  1799  
  1800  		suffix := strings.TrimPrefix(srcPath, srcRoot)
  1801  		for len(suffix) > 0 && suffix[0] == filepath.Separator {
  1802  			suffix = suffix[1:]
  1803  		}
  1804  		dstPath := filepath.Join(dstRoot, suffix)
  1805  
  1806  		var info fs.FileInfo
  1807  		if d.Type()&os.ModeSymlink != 0 {
  1808  			info, err = os.Stat(srcPath)
  1809  		} else {
  1810  			info, err = d.Info()
  1811  		}
  1812  		if err != nil {
  1813  			return err
  1814  		}
  1815  		perm := info.Mode() & os.ModePerm
  1816  
  1817  		// Always copy directories (don't symlink them).
  1818  		// If we add a file in the overlay, we don't want to add it in the original.
  1819  		if info.IsDir() {
  1820  			return os.MkdirAll(dstPath, perm|0200)
  1821  		}
  1822  
  1823  		// If the OS supports symlinks, use them instead of copying bytes.
  1824  		if err := os.Symlink(srcPath, dstPath); err == nil {
  1825  			return nil
  1826  		}
  1827  
  1828  		// Otherwise, copy the bytes.
  1829  		src, err := os.Open(srcPath)
  1830  		if err != nil {
  1831  			return err
  1832  		}
  1833  		defer src.Close()
  1834  
  1835  		dst, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm)
  1836  		if err != nil {
  1837  			return err
  1838  		}
  1839  
  1840  		_, err = io.Copy(dst, src)
  1841  		if closeErr := dst.Close(); err == nil {
  1842  			err = closeErr
  1843  		}
  1844  		return err
  1845  	})
  1846  }
  1847  
  1848  // The following sets of files are excluded from testing depending on configuration.
  1849  // The types2Failures(32Bit) files pass with the 1.17 compiler but don't pass with
  1850  // the 1.18 compiler using the new types2 type checker, or pass with sub-optimal
  1851  // error(s).
  1852  
  1853  // List of files that the compiler cannot errorcheck with the new typechecker (types2).
  1854  var types2Failures = setOf(
  1855  	"shift1.go",               // types2 reports two new errors which are probably not right
  1856  	"fixedbugs/issue10700.go", // types2 should give hint about ptr to interface
  1857  	"fixedbugs/issue18331.go", // missing error about misuse of //go:noescape (irgen needs code from noder)
  1858  	"fixedbugs/issue18419.go", // types2 reports no field or method member, but should say unexported
  1859  	"fixedbugs/issue20233.go", // types2 reports two instead of one error (preference: 1.17 compiler)
  1860  	"fixedbugs/issue20245.go", // types2 reports two instead of one error (preference: 1.17 compiler)
  1861  	"fixedbugs/issue31053.go", // types2 reports "unknown field" instead of "cannot refer to unexported field"
  1862  	"fixedbugs/notinheap.go",  // types2 doesn't report errors about conversions that are invalid due to //go:notinheap
  1863  )
  1864  
  1865  var types2Failures32Bit = setOf(
  1866  	"printbig.go",             // large untyped int passed to print (32-bit)
  1867  	"fixedbugs/bug114.go",     // large untyped int passed to println (32-bit)
  1868  	"fixedbugs/issue23305.go", // large untyped int passed to println (32-bit)
  1869  )
  1870  
  1871  // In all of these cases, the 1.17 compiler reports reasonable errors, but either the
  1872  // 1.17 or 1.18 compiler report extra errors, so we can't match correctly on both. We
  1873  // now set the patterns to match correctly on all the 1.18 errors.
  1874  // This list remains here just as a reference and for comparison - these files all pass.
  1875  var _ = setOf(
  1876  	"import1.go",      // types2 reports extra errors
  1877  	"initializerr.go", // types2 reports extra error
  1878  	"typecheck.go",    // types2 reports extra error at function call
  1879  
  1880  	"fixedbugs/bug176.go", // types2 reports all errors (pref: types2)
  1881  	"fixedbugs/bug195.go", // types2 reports slight different errors, and an extra error
  1882  	"fixedbugs/bug412.go", // types2 produces a follow-on error
  1883  
  1884  	"fixedbugs/issue11614.go", // types2 reports an extra error
  1885  	"fixedbugs/issue17038.go", // types2 doesn't report a follow-on error (pref: types2)
  1886  	"fixedbugs/issue23732.go", // types2 reports different (but ok) line numbers
  1887  	"fixedbugs/issue4510.go",  // types2 reports different (but ok) line numbers
  1888  	"fixedbugs/issue7525b.go", // types2 reports init cycle error on different line - ok otherwise
  1889  	"fixedbugs/issue7525c.go", // types2 reports init cycle error on different line - ok otherwise
  1890  	"fixedbugs/issue7525d.go", // types2 reports init cycle error on different line - ok otherwise
  1891  	"fixedbugs/issue7525e.go", // types2 reports init cycle error on different line - ok otherwise
  1892  	"fixedbugs/issue7525.go",  // types2 reports init cycle error on different line - ok otherwise
  1893  )
  1894  
  1895  func setOf(keys ...string) map[string]bool {
  1896  	m := make(map[string]bool, len(keys))
  1897  	for _, key := range keys {
  1898  		m[key] = true
  1899  	}
  1900  	return m
  1901  }
  1902  
  1903  // splitQuoted splits the string s around each instance of one or more consecutive
  1904  // white space characters while taking into account quotes and escaping, and
  1905  // returns an array of substrings of s or an empty list if s contains only white space.
  1906  // Single quotes and double quotes are recognized to prevent splitting within the
  1907  // quoted region, and are removed from the resulting substrings. If a quote in s
  1908  // isn't closed err will be set and r will have the unclosed argument as the
  1909  // last element. The backslash is used for escaping.
  1910  //
  1911  // For example, the following string:
  1912  //
  1913  //	a b:"c d" 'e''f'  "g\""
  1914  //
  1915  // Would be parsed as:
  1916  //
  1917  //	[]string{"a", "b:c d", "ef", `g"`}
  1918  //
  1919  // [copied from src/go/build/build.go]
  1920  func splitQuoted(s string) (r []string, err error) {
  1921  	var args []string
  1922  	arg := make([]rune, len(s))
  1923  	escaped := false
  1924  	quoted := false
  1925  	quote := '\x00'
  1926  	i := 0
  1927  	for _, rune := range s {
  1928  		switch {
  1929  		case escaped:
  1930  			escaped = false
  1931  		case rune == '\\':
  1932  			escaped = true
  1933  			continue
  1934  		case quote != '\x00':
  1935  			if rune == quote {
  1936  				quote = '\x00'
  1937  				continue
  1938  			}
  1939  		case rune == '"' || rune == '\'':
  1940  			quoted = true
  1941  			quote = rune
  1942  			continue
  1943  		case unicode.IsSpace(rune):
  1944  			if quoted || i > 0 {
  1945  				quoted = false
  1946  				args = append(args, string(arg[:i]))
  1947  				i = 0
  1948  			}
  1949  			continue
  1950  		}
  1951  		arg[i] = rune
  1952  		i++
  1953  	}
  1954  	if quoted || i > 0 {
  1955  		args = append(args, string(arg[:i]))
  1956  	}
  1957  	if quote != 0 {
  1958  		err = errors.New("unclosed quote")
  1959  	} else if escaped {
  1960  		err = errors.New("unfinished escaping")
  1961  	}
  1962  	return args, err
  1963  }
  1964  

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