Source file src/cmd/go/internal/work/exec.go

Documentation: cmd/go/internal/work

     1  // Copyright 2011 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  // Action graph execution.
     6  
     7  package work
     8  
     9  import (
    10  	"bytes"
    11  	"context"
    12  	"encoding/json"
    13  	"errors"
    14  	"fmt"
    15  	"internal/buildcfg"
    16  	exec "internal/execabs"
    17  	"internal/lazyregexp"
    18  	"io"
    19  	"io/fs"
    20  	"log"
    21  	"math/rand"
    22  	"os"
    23  	"path/filepath"
    24  	"regexp"
    25  	"runtime"
    26  	"strconv"
    27  	"strings"
    28  	"sync"
    29  	"time"
    30  
    31  	"cmd/go/internal/base"
    32  	"cmd/go/internal/cache"
    33  	"cmd/go/internal/cfg"
    34  	"cmd/go/internal/fsys"
    35  	"cmd/go/internal/load"
    36  	"cmd/go/internal/modload"
    37  	"cmd/go/internal/str"
    38  	"cmd/go/internal/trace"
    39  )
    40  
    41  // actionList returns the list of actions in the dag rooted at root
    42  // as visited in a depth-first post-order traversal.
    43  func actionList(root *Action) []*Action {
    44  	seen := map[*Action]bool{}
    45  	all := []*Action{}
    46  	var walk func(*Action)
    47  	walk = func(a *Action) {
    48  		if seen[a] {
    49  			return
    50  		}
    51  		seen[a] = true
    52  		for _, a1 := range a.Deps {
    53  			walk(a1)
    54  		}
    55  		all = append(all, a)
    56  	}
    57  	walk(root)
    58  	return all
    59  }
    60  
    61  // do runs the action graph rooted at root.
    62  func (b *Builder) Do(ctx context.Context, root *Action) {
    63  	ctx, span := trace.StartSpan(ctx, "exec.Builder.Do ("+root.Mode+" "+root.Target+")")
    64  	defer span.Done()
    65  
    66  	if !b.IsCmdList {
    67  		// If we're doing real work, take time at the end to trim the cache.
    68  		c := cache.Default()
    69  		defer c.Trim()
    70  	}
    71  
    72  	// Build list of all actions, assigning depth-first post-order priority.
    73  	// The original implementation here was a true queue
    74  	// (using a channel) but it had the effect of getting
    75  	// distracted by low-level leaf actions to the detriment
    76  	// of completing higher-level actions. The order of
    77  	// work does not matter much to overall execution time,
    78  	// but when running "go test std" it is nice to see each test
    79  	// results as soon as possible. The priorities assigned
    80  	// ensure that, all else being equal, the execution prefers
    81  	// to do what it would have done first in a simple depth-first
    82  	// dependency order traversal.
    83  	all := actionList(root)
    84  	for i, a := range all {
    85  		a.priority = i
    86  	}
    87  
    88  	// Write action graph, without timing information, in case we fail and exit early.
    89  	writeActionGraph := func() {
    90  		if file := cfg.DebugActiongraph; file != "" {
    91  			if strings.HasSuffix(file, ".go") {
    92  				// Do not overwrite Go source code in:
    93  				//	go build -debug-actiongraph x.go
    94  				base.Fatalf("go: refusing to write action graph to %v\n", file)
    95  			}
    96  			js := actionGraphJSON(root)
    97  			if err := os.WriteFile(file, []byte(js), 0666); err != nil {
    98  				fmt.Fprintf(os.Stderr, "go: writing action graph: %v\n", err)
    99  				base.SetExitStatus(1)
   100  			}
   101  		}
   102  	}
   103  	writeActionGraph()
   104  
   105  	b.readySema = make(chan bool, len(all))
   106  
   107  	// Initialize per-action execution state.
   108  	for _, a := range all {
   109  		for _, a1 := range a.Deps {
   110  			a1.triggers = append(a1.triggers, a)
   111  		}
   112  		a.pending = len(a.Deps)
   113  		if a.pending == 0 {
   114  			b.ready.push(a)
   115  			b.readySema <- true
   116  		}
   117  	}
   118  
   119  	// Handle runs a single action and takes care of triggering
   120  	// any actions that are runnable as a result.
   121  	handle := func(ctx context.Context, a *Action) {
   122  		if a.json != nil {
   123  			a.json.TimeStart = time.Now()
   124  		}
   125  		var err error
   126  		if a.Func != nil && (!a.Failed || a.IgnoreFail) {
   127  			// TODO(matloob): Better action descriptions
   128  			desc := "Executing action "
   129  			if a.Package != nil {
   130  				desc += "(" + a.Mode + " " + a.Package.Desc() + ")"
   131  			}
   132  			ctx, span := trace.StartSpan(ctx, desc)
   133  			a.traceSpan = span
   134  			for _, d := range a.Deps {
   135  				trace.Flow(ctx, d.traceSpan, a.traceSpan)
   136  			}
   137  			err = a.Func(b, ctx, a)
   138  			span.Done()
   139  		}
   140  		if a.json != nil {
   141  			a.json.TimeDone = time.Now()
   142  		}
   143  
   144  		// The actions run in parallel but all the updates to the
   145  		// shared work state are serialized through b.exec.
   146  		b.exec.Lock()
   147  		defer b.exec.Unlock()
   148  
   149  		if err != nil {
   150  			if err == errPrintedOutput {
   151  				base.SetExitStatus(2)
   152  			} else {
   153  				base.Errorf("%s", err)
   154  			}
   155  			a.Failed = true
   156  		}
   157  
   158  		for _, a0 := range a.triggers {
   159  			if a.Failed {
   160  				a0.Failed = true
   161  			}
   162  			if a0.pending--; a0.pending == 0 {
   163  				b.ready.push(a0)
   164  				b.readySema <- true
   165  			}
   166  		}
   167  
   168  		if a == root {
   169  			close(b.readySema)
   170  		}
   171  	}
   172  
   173  	var wg sync.WaitGroup
   174  
   175  	// Kick off goroutines according to parallelism.
   176  	// If we are using the -n flag (just printing commands)
   177  	// drop the parallelism to 1, both to make the output
   178  	// deterministic and because there is no real work anyway.
   179  	par := cfg.BuildP
   180  	if cfg.BuildN {
   181  		par = 1
   182  	}
   183  	for i := 0; i < par; i++ {
   184  		wg.Add(1)
   185  		go func() {
   186  			ctx := trace.StartGoroutine(ctx)
   187  			defer wg.Done()
   188  			for {
   189  				select {
   190  				case _, ok := <-b.readySema:
   191  					if !ok {
   192  						return
   193  					}
   194  					// Receiving a value from b.readySema entitles
   195  					// us to take from the ready queue.
   196  					b.exec.Lock()
   197  					a := b.ready.pop()
   198  					b.exec.Unlock()
   199  					handle(ctx, a)
   200  				case <-base.Interrupted:
   201  					base.SetExitStatus(1)
   202  					return
   203  				}
   204  			}
   205  		}()
   206  	}
   207  
   208  	wg.Wait()
   209  
   210  	// Write action graph again, this time with timing information.
   211  	writeActionGraph()
   212  }
   213  
   214  // buildActionID computes the action ID for a build action.
   215  func (b *Builder) buildActionID(a *Action) cache.ActionID {
   216  	p := a.Package
   217  	h := cache.NewHash("build " + p.ImportPath)
   218  
   219  	// Configuration independent of compiler toolchain.
   220  	// Note: buildmode has already been accounted for in buildGcflags
   221  	// and should not be inserted explicitly. Most buildmodes use the
   222  	// same compiler settings and can reuse each other's results.
   223  	// If not, the reason is already recorded in buildGcflags.
   224  	fmt.Fprintf(h, "compile\n")
   225  	// Only include the package directory if it may affect the output.
   226  	// We trim workspace paths for all packages when -trimpath is set.
   227  	// The compiler hides the exact value of $GOROOT
   228  	// when building things in GOROOT.
   229  	// Assume b.WorkDir is being trimmed properly.
   230  	// When -trimpath is used with a package built from the module cache,
   231  	// use the module path and version instead of the directory.
   232  	if !p.Goroot && !cfg.BuildTrimpath && !strings.HasPrefix(p.Dir, b.WorkDir) {
   233  		fmt.Fprintf(h, "dir %s\n", p.Dir)
   234  	} else if cfg.BuildTrimpath && p.Module != nil {
   235  		fmt.Fprintf(h, "module %s@%s\n", p.Module.Path, p.Module.Version)
   236  	}
   237  	if p.Module != nil {
   238  		fmt.Fprintf(h, "go %s\n", p.Module.GoVersion)
   239  	}
   240  	fmt.Fprintf(h, "goos %s goarch %s\n", cfg.Goos, cfg.Goarch)
   241  	fmt.Fprintf(h, "import %q\n", p.ImportPath)
   242  	fmt.Fprintf(h, "omitdebug %v standard %v local %v prefix %q\n", p.Internal.OmitDebug, p.Standard, p.Internal.Local, p.Internal.LocalPrefix)
   243  	if cfg.BuildTrimpath {
   244  		fmt.Fprintln(h, "trimpath")
   245  	}
   246  	if p.Internal.ForceLibrary {
   247  		fmt.Fprintf(h, "forcelibrary\n")
   248  	}
   249  	if len(p.CgoFiles)+len(p.SwigFiles)+len(p.SwigCXXFiles) > 0 {
   250  		fmt.Fprintf(h, "cgo %q\n", b.toolID("cgo"))
   251  		cppflags, cflags, cxxflags, fflags, ldflags, _ := b.CFlags(p)
   252  
   253  		ccExe := b.ccExe()
   254  		fmt.Fprintf(h, "CC=%q %q %q %q\n", ccExe, cppflags, cflags, ldflags)
   255  		// Include the C compiler tool ID so that if the C
   256  		// compiler changes we rebuild the package.
   257  		// But don't do that for standard library packages like net,
   258  		// so that the prebuilt .a files from a Go binary install
   259  		// don't need to be rebuilt with the local compiler.
   260  		if !p.Standard {
   261  			if ccID, err := b.gccToolID(ccExe[0], "c"); err == nil {
   262  				fmt.Fprintf(h, "CC ID=%q\n", ccID)
   263  			}
   264  		}
   265  		if len(p.CXXFiles)+len(p.SwigCXXFiles) > 0 {
   266  			cxxExe := b.cxxExe()
   267  			fmt.Fprintf(h, "CXX=%q %q\n", cxxExe, cxxflags)
   268  			if cxxID, err := b.gccToolID(cxxExe[0], "c++"); err == nil {
   269  				fmt.Fprintf(h, "CXX ID=%q\n", cxxID)
   270  			}
   271  		}
   272  		if len(p.FFiles) > 0 {
   273  			fcExe := b.fcExe()
   274  			fmt.Fprintf(h, "FC=%q %q\n", fcExe, fflags)
   275  			if fcID, err := b.gccToolID(fcExe[0], "f95"); err == nil {
   276  				fmt.Fprintf(h, "FC ID=%q\n", fcID)
   277  			}
   278  		}
   279  		// TODO(rsc): Should we include the SWIG version?
   280  	}
   281  	if p.Internal.CoverMode != "" {
   282  		fmt.Fprintf(h, "cover %q %q\n", p.Internal.CoverMode, b.toolID("cover"))
   283  	}
   284  	fmt.Fprintf(h, "modinfo %q\n", p.Internal.BuildInfo)
   285  
   286  	// Configuration specific to compiler toolchain.
   287  	switch cfg.BuildToolchainName {
   288  	default:
   289  		base.Fatalf("buildActionID: unknown build toolchain %q", cfg.BuildToolchainName)
   290  	case "gc":
   291  		fmt.Fprintf(h, "compile %s %q %q\n", b.toolID("compile"), forcedGcflags, p.Internal.Gcflags)
   292  		if len(p.SFiles) > 0 {
   293  			fmt.Fprintf(h, "asm %q %q %q\n", b.toolID("asm"), forcedAsmflags, p.Internal.Asmflags)
   294  		}
   295  
   296  		// GOARM, GOMIPS, etc.
   297  		key, val := cfg.GetArchEnv()
   298  		fmt.Fprintf(h, "%s=%s\n", key, val)
   299  
   300  		if goexperiment := buildcfg.GOEXPERIMENT(); goexperiment != "" {
   301  			fmt.Fprintf(h, "GOEXPERIMENT=%q\n", goexperiment)
   302  		}
   303  
   304  		// TODO(rsc): Convince compiler team not to add more magic environment variables,
   305  		// or perhaps restrict the environment variables passed to subprocesses.
   306  		// Because these are clumsy, undocumented special-case hacks
   307  		// for debugging the compiler, they are not settable using 'go env -w',
   308  		// and so here we use os.Getenv, not cfg.Getenv.
   309  		magic := []string{
   310  			"GOCLOBBERDEADHASH",
   311  			"GOSSAFUNC",
   312  			"GOSSADIR",
   313  			"GOSSAHASH",
   314  		}
   315  		for _, env := range magic {
   316  			if x := os.Getenv(env); x != "" {
   317  				fmt.Fprintf(h, "magic %s=%s\n", env, x)
   318  			}
   319  		}
   320  		if os.Getenv("GOSSAHASH") != "" {
   321  			for i := 0; ; i++ {
   322  				env := fmt.Sprintf("GOSSAHASH%d", i)
   323  				x := os.Getenv(env)
   324  				if x == "" {
   325  					break
   326  				}
   327  				fmt.Fprintf(h, "magic %s=%s\n", env, x)
   328  			}
   329  		}
   330  		if os.Getenv("GSHS_LOGFILE") != "" {
   331  			// Clumsy hack. Compiler writes to this log file,
   332  			// so do not allow use of cache at all.
   333  			// We will still write to the cache but it will be
   334  			// essentially unfindable.
   335  			fmt.Fprintf(h, "nocache %d\n", time.Now().UnixNano())
   336  		}
   337  
   338  	case "gccgo":
   339  		id, err := b.gccToolID(BuildToolchain.compiler(), "go")
   340  		if err != nil {
   341  			base.Fatalf("%v", err)
   342  		}
   343  		fmt.Fprintf(h, "compile %s %q %q\n", id, forcedGccgoflags, p.Internal.Gccgoflags)
   344  		fmt.Fprintf(h, "pkgpath %s\n", gccgoPkgpath(p))
   345  		fmt.Fprintf(h, "ar %q\n", BuildToolchain.(gccgoToolchain).ar())
   346  		if len(p.SFiles) > 0 {
   347  			id, _ = b.gccToolID(BuildToolchain.compiler(), "assembler-with-cpp")
   348  			// Ignore error; different assembler versions
   349  			// are unlikely to make any difference anyhow.
   350  			fmt.Fprintf(h, "asm %q\n", id)
   351  		}
   352  	}
   353  
   354  	// Input files.
   355  	inputFiles := str.StringList(
   356  		p.GoFiles,
   357  		p.CgoFiles,
   358  		p.CFiles,
   359  		p.CXXFiles,
   360  		p.FFiles,
   361  		p.MFiles,
   362  		p.HFiles,
   363  		p.SFiles,
   364  		p.SysoFiles,
   365  		p.SwigFiles,
   366  		p.SwigCXXFiles,
   367  		p.EmbedFiles,
   368  	)
   369  	for _, file := range inputFiles {
   370  		fmt.Fprintf(h, "file %s %s\n", file, b.fileHash(filepath.Join(p.Dir, file)))
   371  	}
   372  	for _, a1 := range a.Deps {
   373  		p1 := a1.Package
   374  		if p1 != nil {
   375  			fmt.Fprintf(h, "import %s %s\n", p1.ImportPath, contentID(a1.buildID))
   376  		}
   377  	}
   378  
   379  	return h.Sum()
   380  }
   381  
   382  // needCgoHdr reports whether the actions triggered by this one
   383  // expect to be able to access the cgo-generated header file.
   384  func (b *Builder) needCgoHdr(a *Action) bool {
   385  	// If this build triggers a header install, run cgo to get the header.
   386  	if !b.IsCmdList && (a.Package.UsesCgo() || a.Package.UsesSwig()) && (cfg.BuildBuildmode == "c-archive" || cfg.BuildBuildmode == "c-shared") {
   387  		for _, t1 := range a.triggers {
   388  			if t1.Mode == "install header" {
   389  				return true
   390  			}
   391  		}
   392  		for _, t1 := range a.triggers {
   393  			for _, t2 := range t1.triggers {
   394  				if t2.Mode == "install header" {
   395  					return true
   396  				}
   397  			}
   398  		}
   399  	}
   400  	return false
   401  }
   402  
   403  // allowedVersion reports whether the version v is an allowed version of go
   404  // (one that we can compile).
   405  // v is known to be of the form "1.23".
   406  func allowedVersion(v string) bool {
   407  	// Special case: no requirement.
   408  	if v == "" {
   409  		return true
   410  	}
   411  	// Special case "1.0" means "go1", which is OK.
   412  	if v == "1.0" {
   413  		return true
   414  	}
   415  	// Otherwise look through release tags of form "go1.23" for one that matches.
   416  	for _, tag := range cfg.BuildContext.ReleaseTags {
   417  		if strings.HasPrefix(tag, "go") && tag[2:] == v {
   418  			return true
   419  		}
   420  	}
   421  	return false
   422  }
   423  
   424  const (
   425  	needBuild uint32 = 1 << iota
   426  	needCgoHdr
   427  	needVet
   428  	needCompiledGoFiles
   429  	needStale
   430  )
   431  
   432  // build is the action for building a single package.
   433  // Note that any new influence on this logic must be reported in b.buildActionID above as well.
   434  func (b *Builder) build(ctx context.Context, a *Action) (err error) {
   435  	p := a.Package
   436  
   437  	bit := func(x uint32, b bool) uint32 {
   438  		if b {
   439  			return x
   440  		}
   441  		return 0
   442  	}
   443  
   444  	cachedBuild := false
   445  	need := bit(needBuild, !b.IsCmdList && a.needBuild || b.NeedExport) |
   446  		bit(needCgoHdr, b.needCgoHdr(a)) |
   447  		bit(needVet, a.needVet) |
   448  		bit(needCompiledGoFiles, b.NeedCompiledGoFiles)
   449  
   450  	if !p.BinaryOnly {
   451  		if b.useCache(a, b.buildActionID(a), p.Target) {
   452  			// We found the main output in the cache.
   453  			// If we don't need any other outputs, we can stop.
   454  			// Otherwise, we need to write files to a.Objdir (needVet, needCgoHdr).
   455  			// Remember that we might have them in cache
   456  			// and check again after we create a.Objdir.
   457  			cachedBuild = true
   458  			a.output = []byte{} // start saving output in case we miss any cache results
   459  			need &^= needBuild
   460  			if b.NeedExport {
   461  				p.Export = a.built
   462  				p.BuildID = a.buildID
   463  			}
   464  			if need&needCompiledGoFiles != 0 {
   465  				if err := b.loadCachedSrcFiles(a); err == nil {
   466  					need &^= needCompiledGoFiles
   467  				}
   468  			}
   469  		}
   470  
   471  		// Source files might be cached, even if the full action is not
   472  		// (e.g., go list -compiled -find).
   473  		if !cachedBuild && need&needCompiledGoFiles != 0 {
   474  			if err := b.loadCachedSrcFiles(a); err == nil {
   475  				need &^= needCompiledGoFiles
   476  			}
   477  		}
   478  
   479  		if need == 0 {
   480  			return nil
   481  		}
   482  		defer b.flushOutput(a)
   483  	}
   484  
   485  	defer func() {
   486  		if err != nil && err != errPrintedOutput {
   487  			err = fmt.Errorf("go build %s: %v", a.Package.ImportPath, err)
   488  		}
   489  		if err != nil && b.IsCmdList && b.NeedError && p.Error == nil {
   490  			p.Error = &load.PackageError{Err: err}
   491  		}
   492  	}()
   493  	if cfg.BuildN {
   494  		// In -n mode, print a banner between packages.
   495  		// The banner is five lines so that when changes to
   496  		// different sections of the bootstrap script have to
   497  		// be merged, the banners give patch something
   498  		// to use to find its context.
   499  		b.Print("\n#\n# " + a.Package.ImportPath + "\n#\n\n")
   500  	}
   501  
   502  	if cfg.BuildV {
   503  		b.Print(a.Package.ImportPath + "\n")
   504  	}
   505  
   506  	if a.Package.BinaryOnly {
   507  		p.Stale = true
   508  		p.StaleReason = "binary-only packages are no longer supported"
   509  		if b.IsCmdList {
   510  			return nil
   511  		}
   512  		return errors.New("binary-only packages are no longer supported")
   513  	}
   514  
   515  	if err := b.Mkdir(a.Objdir); err != nil {
   516  		return err
   517  	}
   518  	objdir := a.Objdir
   519  
   520  	// Load cached cgo header, but only if we're skipping the main build (cachedBuild==true).
   521  	if cachedBuild && need&needCgoHdr != 0 {
   522  		if err := b.loadCachedCgoHdr(a); err == nil {
   523  			need &^= needCgoHdr
   524  		}
   525  	}
   526  
   527  	// Load cached vet config, but only if that's all we have left
   528  	// (need == needVet, not testing just the one bit).
   529  	// If we are going to do a full build anyway,
   530  	// we're going to regenerate the files below anyway.
   531  	if need == needVet {
   532  		if err := b.loadCachedVet(a); err == nil {
   533  			need &^= needVet
   534  		}
   535  	}
   536  	if need == 0 {
   537  		return nil
   538  	}
   539  
   540  	if err := allowInstall(a); err != nil {
   541  		return err
   542  	}
   543  
   544  	// make target directory
   545  	dir, _ := filepath.Split(a.Target)
   546  	if dir != "" {
   547  		if err := b.Mkdir(dir); err != nil {
   548  			return err
   549  		}
   550  	}
   551  
   552  	gofiles := str.StringList(a.Package.GoFiles)
   553  	cgofiles := str.StringList(a.Package.CgoFiles)
   554  	cfiles := str.StringList(a.Package.CFiles)
   555  	sfiles := str.StringList(a.Package.SFiles)
   556  	cxxfiles := str.StringList(a.Package.CXXFiles)
   557  	var objects, cgoObjects, pcCFLAGS, pcLDFLAGS []string
   558  
   559  	if a.Package.UsesCgo() || a.Package.UsesSwig() {
   560  		if pcCFLAGS, pcLDFLAGS, err = b.getPkgConfigFlags(a.Package); err != nil {
   561  			return
   562  		}
   563  	}
   564  
   565  	// Compute overlays for .c/.cc/.h/etc. and if there are any overlays
   566  	// put correct contents of all those files in the objdir, to ensure
   567  	// the correct headers are included. nonGoOverlay is the overlay that
   568  	// points from nongo files to the copied files in objdir.
   569  	nonGoFileLists := [][]string{a.Package.CFiles, a.Package.SFiles, a.Package.CXXFiles, a.Package.HFiles, a.Package.FFiles}
   570  OverlayLoop:
   571  	for _, fs := range nonGoFileLists {
   572  		for _, f := range fs {
   573  			if _, ok := fsys.OverlayPath(mkAbs(p.Dir, f)); ok {
   574  				a.nonGoOverlay = make(map[string]string)
   575  				break OverlayLoop
   576  			}
   577  		}
   578  	}
   579  	if a.nonGoOverlay != nil {
   580  		for _, fs := range nonGoFileLists {
   581  			for i := range fs {
   582  				from := mkAbs(p.Dir, fs[i])
   583  				opath, _ := fsys.OverlayPath(from)
   584  				dst := objdir + filepath.Base(fs[i])
   585  				if err := b.copyFile(dst, opath, 0666, false); err != nil {
   586  					return err
   587  				}
   588  				a.nonGoOverlay[from] = dst
   589  			}
   590  		}
   591  	}
   592  
   593  	// Run SWIG on each .swig and .swigcxx file.
   594  	// Each run will generate two files, a .go file and a .c or .cxx file.
   595  	// The .go file will use import "C" and is to be processed by cgo.
   596  	if a.Package.UsesSwig() {
   597  		outGo, outC, outCXX, err := b.swig(a, a.Package, objdir, pcCFLAGS)
   598  		if err != nil {
   599  			return err
   600  		}
   601  		cgofiles = append(cgofiles, outGo...)
   602  		cfiles = append(cfiles, outC...)
   603  		cxxfiles = append(cxxfiles, outCXX...)
   604  	}
   605  
   606  	// If we're doing coverage, preprocess the .go files and put them in the work directory
   607  	if a.Package.Internal.CoverMode != "" {
   608  		for i, file := range str.StringList(gofiles, cgofiles) {
   609  			var sourceFile string
   610  			var coverFile string
   611  			var key string
   612  			if strings.HasSuffix(file, ".cgo1.go") {
   613  				// cgo files have absolute paths
   614  				base := filepath.Base(file)
   615  				sourceFile = file
   616  				coverFile = objdir + base
   617  				key = strings.TrimSuffix(base, ".cgo1.go") + ".go"
   618  			} else {
   619  				sourceFile = filepath.Join(a.Package.Dir, file)
   620  				coverFile = objdir + file
   621  				key = file
   622  			}
   623  			coverFile = strings.TrimSuffix(coverFile, ".go") + ".cover.go"
   624  			cover := a.Package.Internal.CoverVars[key]
   625  			if cover == nil || base.IsTestFile(file) {
   626  				// Not covering this file.
   627  				continue
   628  			}
   629  			if err := b.cover(a, coverFile, sourceFile, cover.Var); err != nil {
   630  				return err
   631  			}
   632  			if i < len(gofiles) {
   633  				gofiles[i] = coverFile
   634  			} else {
   635  				cgofiles[i-len(gofiles)] = coverFile
   636  			}
   637  		}
   638  	}
   639  
   640  	// Run cgo.
   641  	if a.Package.UsesCgo() || a.Package.UsesSwig() {
   642  		// In a package using cgo, cgo compiles the C, C++ and assembly files with gcc.
   643  		// There is one exception: runtime/cgo's job is to bridge the
   644  		// cgo and non-cgo worlds, so it necessarily has files in both.
   645  		// In that case gcc only gets the gcc_* files.
   646  		var gccfiles []string
   647  		gccfiles = append(gccfiles, cfiles...)
   648  		cfiles = nil
   649  		if a.Package.Standard && a.Package.ImportPath == "runtime/cgo" {
   650  			filter := func(files, nongcc, gcc []string) ([]string, []string) {
   651  				for _, f := range files {
   652  					if strings.HasPrefix(f, "gcc_") {
   653  						gcc = append(gcc, f)
   654  					} else {
   655  						nongcc = append(nongcc, f)
   656  					}
   657  				}
   658  				return nongcc, gcc
   659  			}
   660  			sfiles, gccfiles = filter(sfiles, sfiles[:0], gccfiles)
   661  		} else {
   662  			for _, sfile := range sfiles {
   663  				data, err := os.ReadFile(filepath.Join(a.Package.Dir, sfile))
   664  				if err == nil {
   665  					if bytes.HasPrefix(data, []byte("TEXT")) || bytes.Contains(data, []byte("\nTEXT")) ||
   666  						bytes.HasPrefix(data, []byte("DATA")) || bytes.Contains(data, []byte("\nDATA")) ||
   667  						bytes.HasPrefix(data, []byte("GLOBL")) || bytes.Contains(data, []byte("\nGLOBL")) {
   668  						return fmt.Errorf("package using cgo has Go assembly file %s", sfile)
   669  					}
   670  				}
   671  			}
   672  			gccfiles = append(gccfiles, sfiles...)
   673  			sfiles = nil
   674  		}
   675  
   676  		outGo, outObj, err := b.cgo(a, base.Tool("cgo"), objdir, pcCFLAGS, pcLDFLAGS, mkAbsFiles(a.Package.Dir, cgofiles), gccfiles, cxxfiles, a.Package.MFiles, a.Package.FFiles)
   677  
   678  		// The files in cxxfiles have now been handled by b.cgo.
   679  		cxxfiles = nil
   680  
   681  		if err != nil {
   682  			return err
   683  		}
   684  		if cfg.BuildToolchainName == "gccgo" {
   685  			cgoObjects = append(cgoObjects, a.Objdir+"_cgo_flags")
   686  		}
   687  		cgoObjects = append(cgoObjects, outObj...)
   688  		gofiles = append(gofiles, outGo...)
   689  
   690  		switch cfg.BuildBuildmode {
   691  		case "c-archive", "c-shared":
   692  			b.cacheCgoHdr(a)
   693  		}
   694  	}
   695  
   696  	var srcfiles []string // .go and non-.go
   697  	srcfiles = append(srcfiles, gofiles...)
   698  	srcfiles = append(srcfiles, sfiles...)
   699  	srcfiles = append(srcfiles, cfiles...)
   700  	srcfiles = append(srcfiles, cxxfiles...)
   701  	b.cacheSrcFiles(a, srcfiles)
   702  
   703  	// Running cgo generated the cgo header.
   704  	need &^= needCgoHdr
   705  
   706  	// Sanity check only, since Package.load already checked as well.
   707  	if len(gofiles) == 0 {
   708  		return &load.NoGoError{Package: a.Package}
   709  	}
   710  
   711  	// Prepare Go vet config if needed.
   712  	if need&needVet != 0 {
   713  		buildVetConfig(a, srcfiles)
   714  		need &^= needVet
   715  	}
   716  	if need&needCompiledGoFiles != 0 {
   717  		if err := b.loadCachedSrcFiles(a); err != nil {
   718  			return fmt.Errorf("loading compiled Go files from cache: %w", err)
   719  		}
   720  		need &^= needCompiledGoFiles
   721  	}
   722  	if need == 0 {
   723  		// Nothing left to do.
   724  		return nil
   725  	}
   726  
   727  	// Collect symbol ABI requirements from assembly.
   728  	symabis, err := BuildToolchain.symabis(b, a, sfiles)
   729  	if err != nil {
   730  		return err
   731  	}
   732  
   733  	// Prepare Go import config.
   734  	// We start it off with a comment so it can't be empty, so icfg.Bytes() below is never nil.
   735  	// It should never be empty anyway, but there have been bugs in the past that resulted
   736  	// in empty configs, which then unfortunately turn into "no config passed to compiler",
   737  	// and the compiler falls back to looking in pkg itself, which mostly works,
   738  	// except when it doesn't.
   739  	var icfg bytes.Buffer
   740  	fmt.Fprintf(&icfg, "# import config\n")
   741  	for i, raw := range a.Package.Internal.RawImports {
   742  		final := a.Package.Imports[i]
   743  		if final != raw {
   744  			fmt.Fprintf(&icfg, "importmap %s=%s\n", raw, final)
   745  		}
   746  	}
   747  	for _, a1 := range a.Deps {
   748  		p1 := a1.Package
   749  		if p1 == nil || p1.ImportPath == "" || a1.built == "" {
   750  			continue
   751  		}
   752  		fmt.Fprintf(&icfg, "packagefile %s=%s\n", p1.ImportPath, a1.built)
   753  	}
   754  
   755  	// Prepare Go embed config if needed.
   756  	// Unlike the import config, it's okay for the embed config to be empty.
   757  	var embedcfg []byte
   758  	if len(p.Internal.Embed) > 0 {
   759  		var embed struct {
   760  			Patterns map[string][]string
   761  			Files    map[string]string
   762  		}
   763  		embed.Patterns = p.Internal.Embed
   764  		embed.Files = make(map[string]string)
   765  		for _, file := range p.EmbedFiles {
   766  			embed.Files[file] = filepath.Join(p.Dir, file)
   767  		}
   768  		js, err := json.MarshalIndent(&embed, "", "\t")
   769  		if err != nil {
   770  			return fmt.Errorf("marshal embedcfg: %v", err)
   771  		}
   772  		embedcfg = js
   773  	}
   774  
   775  	if p.Internal.BuildInfo != "" && cfg.ModulesEnabled {
   776  		if err := b.writeFile(objdir+"_gomod_.go", modload.ModInfoProg(p.Internal.BuildInfo, cfg.BuildToolchainName == "gccgo")); err != nil {
   777  			return err
   778  		}
   779  		gofiles = append(gofiles, objdir+"_gomod_.go")
   780  	}
   781  
   782  	// Compile Go.
   783  	objpkg := objdir + "_pkg_.a"
   784  	ofile, out, err := BuildToolchain.gc(b, a, objpkg, icfg.Bytes(), embedcfg, symabis, len(sfiles) > 0, gofiles)
   785  	if len(out) > 0 {
   786  		output := b.processOutput(out)
   787  		if p.Module != nil && !allowedVersion(p.Module.GoVersion) {
   788  			output += "note: module requires Go " + p.Module.GoVersion + "\n"
   789  		}
   790  		b.showOutput(a, a.Package.Dir, a.Package.Desc(), output)
   791  		if err != nil {
   792  			return errPrintedOutput
   793  		}
   794  	}
   795  	if err != nil {
   796  		if p.Module != nil && !allowedVersion(p.Module.GoVersion) {
   797  			b.showOutput(a, a.Package.Dir, a.Package.Desc(), "note: module requires Go "+p.Module.GoVersion+"\n")
   798  		}
   799  		return err
   800  	}
   801  	if ofile != objpkg {
   802  		objects = append(objects, ofile)
   803  	}
   804  
   805  	// Copy .h files named for goos or goarch or goos_goarch
   806  	// to names using GOOS and GOARCH.
   807  	// For example, defs_linux_amd64.h becomes defs_GOOS_GOARCH.h.
   808  	_goos_goarch := "_" + cfg.Goos + "_" + cfg.Goarch
   809  	_goos := "_" + cfg.Goos
   810  	_goarch := "_" + cfg.Goarch
   811  	for _, file := range a.Package.HFiles {
   812  		name, ext := fileExtSplit(file)
   813  		switch {
   814  		case strings.HasSuffix(name, _goos_goarch):
   815  			targ := file[:len(name)-len(_goos_goarch)] + "_GOOS_GOARCH." + ext
   816  			if err := b.copyFile(objdir+targ, filepath.Join(a.Package.Dir, file), 0666, true); err != nil {
   817  				return err
   818  			}
   819  		case strings.HasSuffix(name, _goarch):
   820  			targ := file[:len(name)-len(_goarch)] + "_GOARCH." + ext
   821  			if err := b.copyFile(objdir+targ, filepath.Join(a.Package.Dir, file), 0666, true); err != nil {
   822  				return err
   823  			}
   824  		case strings.HasSuffix(name, _goos):
   825  			targ := file[:len(name)-len(_goos)] + "_GOOS." + ext
   826  			if err := b.copyFile(objdir+targ, filepath.Join(a.Package.Dir, file), 0666, true); err != nil {
   827  				return err
   828  			}
   829  		}
   830  	}
   831  
   832  	for _, file := range cfiles {
   833  		out := file[:len(file)-len(".c")] + ".o"
   834  		if err := BuildToolchain.cc(b, a, objdir+out, file); err != nil {
   835  			return err
   836  		}
   837  		objects = append(objects, out)
   838  	}
   839  
   840  	// Assemble .s files.
   841  	if len(sfiles) > 0 {
   842  		ofiles, err := BuildToolchain.asm(b, a, sfiles)
   843  		if err != nil {
   844  			return err
   845  		}
   846  		objects = append(objects, ofiles...)
   847  	}
   848  
   849  	// For gccgo on ELF systems, we write the build ID as an assembler file.
   850  	// This lets us set the SHF_EXCLUDE flag.
   851  	// This is read by readGccgoArchive in cmd/internal/buildid/buildid.go.
   852  	if a.buildID != "" && cfg.BuildToolchainName == "gccgo" {
   853  		switch cfg.Goos {
   854  		case "aix", "android", "dragonfly", "freebsd", "illumos", "linux", "netbsd", "openbsd", "solaris":
   855  			asmfile, err := b.gccgoBuildIDFile(a)
   856  			if err != nil {
   857  				return err
   858  			}
   859  			ofiles, err := BuildToolchain.asm(b, a, []string{asmfile})
   860  			if err != nil {
   861  				return err
   862  			}
   863  			objects = append(objects, ofiles...)
   864  		}
   865  	}
   866  
   867  	// NOTE(rsc): On Windows, it is critically important that the
   868  	// gcc-compiled objects (cgoObjects) be listed after the ordinary
   869  	// objects in the archive. I do not know why this is.
   870  	// https://golang.org/issue/2601
   871  	objects = append(objects, cgoObjects...)
   872  
   873  	// Add system object files.
   874  	for _, syso := range a.Package.SysoFiles {
   875  		objects = append(objects, filepath.Join(a.Package.Dir, syso))
   876  	}
   877  
   878  	// Pack into archive in objdir directory.
   879  	// If the Go compiler wrote an archive, we only need to add the
   880  	// object files for non-Go sources to the archive.
   881  	// If the Go compiler wrote an archive and the package is entirely
   882  	// Go sources, there is no pack to execute at all.
   883  	if len(objects) > 0 {
   884  		if err := BuildToolchain.pack(b, a, objpkg, objects); err != nil {
   885  			return err
   886  		}
   887  	}
   888  
   889  	if err := b.updateBuildID(a, objpkg, true); err != nil {
   890  		return err
   891  	}
   892  
   893  	a.built = objpkg
   894  	return nil
   895  }
   896  
   897  func (b *Builder) cacheObjdirFile(a *Action, c *cache.Cache, name string) error {
   898  	f, err := os.Open(a.Objdir + name)
   899  	if err != nil {
   900  		return err
   901  	}
   902  	defer f.Close()
   903  	_, _, err = c.Put(cache.Subkey(a.actionID, name), f)
   904  	return err
   905  }
   906  
   907  func (b *Builder) findCachedObjdirFile(a *Action, c *cache.Cache, name string) (string, error) {
   908  	file, _, err := c.GetFile(cache.Subkey(a.actionID, name))
   909  	if err != nil {
   910  		return "", fmt.Errorf("loading cached file %s: %w", name, err)
   911  	}
   912  	return file, nil
   913  }
   914  
   915  func (b *Builder) loadCachedObjdirFile(a *Action, c *cache.Cache, name string) error {
   916  	cached, err := b.findCachedObjdirFile(a, c, name)
   917  	if err != nil {
   918  		return err
   919  	}
   920  	return b.copyFile(a.Objdir+name, cached, 0666, true)
   921  }
   922  
   923  func (b *Builder) cacheCgoHdr(a *Action) {
   924  	c := cache.Default()
   925  	b.cacheObjdirFile(a, c, "_cgo_install.h")
   926  }
   927  
   928  func (b *Builder) loadCachedCgoHdr(a *Action) error {
   929  	c := cache.Default()
   930  	return b.loadCachedObjdirFile(a, c, "_cgo_install.h")
   931  }
   932  
   933  func (b *Builder) cacheSrcFiles(a *Action, srcfiles []string) {
   934  	c := cache.Default()
   935  	var buf bytes.Buffer
   936  	for _, file := range srcfiles {
   937  		if !strings.HasPrefix(file, a.Objdir) {
   938  			// not generated
   939  			buf.WriteString("./")
   940  			buf.WriteString(file)
   941  			buf.WriteString("\n")
   942  			continue
   943  		}
   944  		name := file[len(a.Objdir):]
   945  		buf.WriteString(name)
   946  		buf.WriteString("\n")
   947  		if err := b.cacheObjdirFile(a, c, name); err != nil {
   948  			return
   949  		}
   950  	}
   951  	c.PutBytes(cache.Subkey(a.actionID, "srcfiles"), buf.Bytes())
   952  }
   953  
   954  func (b *Builder) loadCachedVet(a *Action) error {
   955  	c := cache.Default()
   956  	list, _, err := c.GetBytes(cache.Subkey(a.actionID, "srcfiles"))
   957  	if err != nil {
   958  		return fmt.Errorf("reading srcfiles list: %w", err)
   959  	}
   960  	var srcfiles []string
   961  	for _, name := range strings.Split(string(list), "\n") {
   962  		if name == "" { // end of list
   963  			continue
   964  		}
   965  		if strings.HasPrefix(name, "./") {
   966  			srcfiles = append(srcfiles, name[2:])
   967  			continue
   968  		}
   969  		if err := b.loadCachedObjdirFile(a, c, name); err != nil {
   970  			return err
   971  		}
   972  		srcfiles = append(srcfiles, a.Objdir+name)
   973  	}
   974  	buildVetConfig(a, srcfiles)
   975  	return nil
   976  }
   977  
   978  func (b *Builder) loadCachedSrcFiles(a *Action) error {
   979  	c := cache.Default()
   980  	list, _, err := c.GetBytes(cache.Subkey(a.actionID, "srcfiles"))
   981  	if err != nil {
   982  		return fmt.Errorf("reading srcfiles list: %w", err)
   983  	}
   984  	var files []string
   985  	for _, name := range strings.Split(string(list), "\n") {
   986  		if name == "" { // end of list
   987  			continue
   988  		}
   989  		if strings.HasPrefix(name, "./") {
   990  			files = append(files, name[len("./"):])
   991  			continue
   992  		}
   993  		file, err := b.findCachedObjdirFile(a, c, name)
   994  		if err != nil {
   995  			return fmt.Errorf("finding %s: %w", name, err)
   996  		}
   997  		files = append(files, file)
   998  	}
   999  	a.Package.CompiledGoFiles = files
  1000  	return nil
  1001  }
  1002  
  1003  // vetConfig is the configuration passed to vet describing a single package.
  1004  type vetConfig struct {
  1005  	ID           string   // package ID (example: "fmt [fmt.test]")
  1006  	Compiler     string   // compiler name (gc, gccgo)
  1007  	Dir          string   // directory containing package
  1008  	ImportPath   string   // canonical import path ("package path")
  1009  	GoFiles      []string // absolute paths to package source files
  1010  	NonGoFiles   []string // absolute paths to package non-Go files
  1011  	IgnoredFiles []string // absolute paths to ignored source files
  1012  
  1013  	ImportMap   map[string]string // map import path in source code to package path
  1014  	PackageFile map[string]string // map package path to .a file with export data
  1015  	Standard    map[string]bool   // map package path to whether it's in the standard library
  1016  	PackageVetx map[string]string // map package path to vetx data from earlier vet run
  1017  	VetxOnly    bool              // only compute vetx data; don't report detected problems
  1018  	VetxOutput  string            // write vetx data to this output file
  1019  
  1020  	SucceedOnTypecheckFailure bool // awful hack; see #18395 and below
  1021  }
  1022  
  1023  func buildVetConfig(a *Action, srcfiles []string) {
  1024  	// Classify files based on .go extension.
  1025  	// srcfiles does not include raw cgo files.
  1026  	var gofiles, nongofiles []string
  1027  	for _, name := range srcfiles {
  1028  		if strings.HasSuffix(name, ".go") {
  1029  			gofiles = append(gofiles, name)
  1030  		} else {
  1031  			nongofiles = append(nongofiles, name)
  1032  		}
  1033  	}
  1034  
  1035  	ignored := str.StringList(a.Package.IgnoredGoFiles, a.Package.IgnoredOtherFiles)
  1036  
  1037  	// Pass list of absolute paths to vet,
  1038  	// so that vet's error messages will use absolute paths,
  1039  	// so that we can reformat them relative to the directory
  1040  	// in which the go command is invoked.
  1041  	vcfg := &vetConfig{
  1042  		ID:           a.Package.ImportPath,
  1043  		Compiler:     cfg.BuildToolchainName,
  1044  		Dir:          a.Package.Dir,
  1045  		GoFiles:      mkAbsFiles(a.Package.Dir, gofiles),
  1046  		NonGoFiles:   mkAbsFiles(a.Package.Dir, nongofiles),
  1047  		IgnoredFiles: mkAbsFiles(a.Package.Dir, ignored),
  1048  		ImportPath:   a.Package.ImportPath,
  1049  		ImportMap:    make(map[string]string),
  1050  		PackageFile:  make(map[string]string),
  1051  		Standard:     make(map[string]bool),
  1052  	}
  1053  	a.vetCfg = vcfg
  1054  	for i, raw := range a.Package.Internal.RawImports {
  1055  		final := a.Package.Imports[i]
  1056  		vcfg.ImportMap[raw] = final
  1057  	}
  1058  
  1059  	// Compute the list of mapped imports in the vet config
  1060  	// so that we can add any missing mappings below.
  1061  	vcfgMapped := make(map[string]bool)
  1062  	for _, p := range vcfg.ImportMap {
  1063  		vcfgMapped[p] = true
  1064  	}
  1065  
  1066  	for _, a1 := range a.Deps {
  1067  		p1 := a1.Package
  1068  		if p1 == nil || p1.ImportPath == "" {
  1069  			continue
  1070  		}
  1071  		// Add import mapping if needed
  1072  		// (for imports like "runtime/cgo" that appear only in generated code).
  1073  		if !vcfgMapped[p1.ImportPath] {
  1074  			vcfg.ImportMap[p1.ImportPath] = p1.ImportPath
  1075  		}
  1076  		if a1.built != "" {
  1077  			vcfg.PackageFile[p1.ImportPath] = a1.built
  1078  		}
  1079  		if p1.Standard {
  1080  			vcfg.Standard[p1.ImportPath] = true
  1081  		}
  1082  	}
  1083  }
  1084  
  1085  // VetTool is the path to an alternate vet tool binary.
  1086  // The caller is expected to set it (if needed) before executing any vet actions.
  1087  var VetTool string
  1088  
  1089  // VetFlags are the default flags to pass to vet.
  1090  // The caller is expected to set them before executing any vet actions.
  1091  var VetFlags []string
  1092  
  1093  // VetExplicit records whether the vet flags were set explicitly on the command line.
  1094  var VetExplicit bool
  1095  
  1096  func (b *Builder) vet(ctx context.Context, a *Action) error {
  1097  	// a.Deps[0] is the build of the package being vetted.
  1098  	// a.Deps[1] is the build of the "fmt" package.
  1099  
  1100  	a.Failed = false // vet of dependency may have failed but we can still succeed
  1101  
  1102  	if a.Deps[0].Failed {
  1103  		// The build of the package has failed. Skip vet check.
  1104  		// Vet could return export data for non-typecheck errors,
  1105  		// but we ignore it because the package cannot be compiled.
  1106  		return nil
  1107  	}
  1108  
  1109  	vcfg := a.Deps[0].vetCfg
  1110  	if vcfg == nil {
  1111  		// Vet config should only be missing if the build failed.
  1112  		return fmt.Errorf("vet config not found")
  1113  	}
  1114  
  1115  	vcfg.VetxOnly = a.VetxOnly
  1116  	vcfg.VetxOutput = a.Objdir + "vet.out"
  1117  	vcfg.PackageVetx = make(map[string]string)
  1118  
  1119  	h := cache.NewHash("vet " + a.Package.ImportPath)
  1120  	fmt.Fprintf(h, "vet %q\n", b.toolID("vet"))
  1121  
  1122  	vetFlags := VetFlags
  1123  
  1124  	// In GOROOT, we enable all the vet tests during 'go test',
  1125  	// not just the high-confidence subset. This gets us extra
  1126  	// checking for the standard library (at some compliance cost)
  1127  	// and helps us gain experience about how well the checks
  1128  	// work, to help decide which should be turned on by default.
  1129  	// The command-line still wins.
  1130  	//
  1131  	// Note that this flag change applies even when running vet as
  1132  	// a dependency of vetting a package outside std.
  1133  	// (Otherwise we'd have to introduce a whole separate
  1134  	// space of "vet fmt as a dependency of a std top-level vet"
  1135  	// versus "vet fmt as a dependency of a non-std top-level vet".)
  1136  	// This is OK as long as the packages that are farther down the
  1137  	// dependency tree turn on *more* analysis, as here.
  1138  	// (The unsafeptr check does not write any facts for use by
  1139  	// later vet runs, nor does unreachable.)
  1140  	if a.Package.Goroot && !VetExplicit && VetTool == "" {
  1141  		// Turn off -unsafeptr checks.
  1142  		// There's too much unsafe.Pointer code
  1143  		// that vet doesn't like in low-level packages
  1144  		// like runtime, sync, and reflect.
  1145  		// Note that $GOROOT/src/buildall.bash
  1146  		// does the same for the misc-compile trybots
  1147  		// and should be updated if these flags are
  1148  		// changed here.
  1149  		vetFlags = []string{"-unsafeptr=false"}
  1150  
  1151  		// Also turn off -unreachable checks during go test.
  1152  		// During testing it is very common to make changes
  1153  		// like hard-coded forced returns or panics that make
  1154  		// code unreachable. It's unreasonable to insist on files
  1155  		// not having any unreachable code during "go test".
  1156  		// (buildall.bash still runs with -unreachable enabled
  1157  		// for the overall whole-tree scan.)
  1158  		if cfg.CmdName == "test" {
  1159  			vetFlags = append(vetFlags, "-unreachable=false")
  1160  		}
  1161  	}
  1162  
  1163  	// Note: We could decide that vet should compute export data for
  1164  	// all analyses, in which case we don't need to include the flags here.
  1165  	// But that would mean that if an analysis causes problems like
  1166  	// unexpected crashes there would be no way to turn it off.
  1167  	// It seems better to let the flags disable export analysis too.
  1168  	fmt.Fprintf(h, "vetflags %q\n", vetFlags)
  1169  
  1170  	fmt.Fprintf(h, "pkg %q\n", a.Deps[0].actionID)
  1171  	for _, a1 := range a.Deps {
  1172  		if a1.Mode == "vet" && a1.built != "" {
  1173  			fmt.Fprintf(h, "vetout %q %s\n", a1.Package.ImportPath, b.fileHash(a1.built))
  1174  			vcfg.PackageVetx[a1.Package.ImportPath] = a1.built
  1175  		}
  1176  	}
  1177  	key := cache.ActionID(h.Sum())
  1178  
  1179  	if vcfg.VetxOnly && !cfg.BuildA {
  1180  		c := cache.Default()
  1181  		if file, _, err := c.GetFile(key); err == nil {
  1182  			a.built = file
  1183  			return nil
  1184  		}
  1185  	}
  1186  
  1187  	js, err := json.MarshalIndent(vcfg, "", "\t")
  1188  	if err != nil {
  1189  		return fmt.Errorf("internal error marshaling vet config: %v", err)
  1190  	}
  1191  	js = append(js, '\n')
  1192  	if err := b.writeFile(a.Objdir+"vet.cfg", js); err != nil {
  1193  		return err
  1194  	}
  1195  
  1196  	// TODO(rsc): Why do we pass $GCCGO to go vet?
  1197  	env := b.cCompilerEnv()
  1198  	if cfg.BuildToolchainName == "gccgo" {
  1199  		env = append(env, "GCCGO="+BuildToolchain.compiler())
  1200  	}
  1201  
  1202  	p := a.Package
  1203  	tool := VetTool
  1204  	if tool == "" {
  1205  		tool = base.Tool("vet")
  1206  	}
  1207  	runErr := b.run(a, p.Dir, p.ImportPath, env, cfg.BuildToolexec, tool, vetFlags, a.Objdir+"vet.cfg")
  1208  
  1209  	// If vet wrote export data, save it for input to future vets.
  1210  	if f, err := os.Open(vcfg.VetxOutput); err == nil {
  1211  		a.built = vcfg.VetxOutput
  1212  		cache.Default().Put(key, f)
  1213  		f.Close()
  1214  	}
  1215  
  1216  	return runErr
  1217  }
  1218  
  1219  // linkActionID computes the action ID for a link action.
  1220  func (b *Builder) linkActionID(a *Action) cache.ActionID {
  1221  	p := a.Package
  1222  	h := cache.NewHash("link " + p.ImportPath)
  1223  
  1224  	// Toolchain-independent configuration.
  1225  	fmt.Fprintf(h, "link\n")
  1226  	fmt.Fprintf(h, "buildmode %s goos %s goarch %s\n", cfg.BuildBuildmode, cfg.Goos, cfg.Goarch)
  1227  	fmt.Fprintf(h, "import %q\n", p.ImportPath)
  1228  	fmt.Fprintf(h, "omitdebug %v standard %v local %v prefix %q\n", p.Internal.OmitDebug, p.Standard, p.Internal.Local, p.Internal.LocalPrefix)
  1229  	if cfg.BuildTrimpath {
  1230  		fmt.Fprintln(h, "trimpath")
  1231  	}
  1232  
  1233  	// Toolchain-dependent configuration, shared with b.linkSharedActionID.
  1234  	b.printLinkerConfig(h, p)
  1235  
  1236  	// Input files.
  1237  	for _, a1 := range a.Deps {
  1238  		p1 := a1.Package
  1239  		if p1 != nil {
  1240  			if a1.built != "" || a1.buildID != "" {
  1241  				buildID := a1.buildID
  1242  				if buildID == "" {
  1243  					buildID = b.buildID(a1.built)
  1244  				}
  1245  				fmt.Fprintf(h, "packagefile %s=%s\n", p1.ImportPath, contentID(buildID))
  1246  			}
  1247  			// Because we put package main's full action ID into the binary's build ID,
  1248  			// we must also put the full action ID into the binary's action ID hash.
  1249  			if p1.Name == "main" {
  1250  				fmt.Fprintf(h, "packagemain %s\n", a1.buildID)
  1251  			}
  1252  			if p1.Shlib != "" {
  1253  				fmt.Fprintf(h, "packageshlib %s=%s\n", p1.ImportPath, contentID(b.buildID(p1.Shlib)))
  1254  			}
  1255  		}
  1256  	}
  1257  
  1258  	return h.Sum()
  1259  }
  1260  
  1261  // printLinkerConfig prints the linker config into the hash h,
  1262  // as part of the computation of a linker-related action ID.
  1263  func (b *Builder) printLinkerConfig(h io.Writer, p *load.Package) {
  1264  	switch cfg.BuildToolchainName {
  1265  	default:
  1266  		base.Fatalf("linkActionID: unknown toolchain %q", cfg.BuildToolchainName)
  1267  
  1268  	case "gc":
  1269  		fmt.Fprintf(h, "link %s %q %s\n", b.toolID("link"), forcedLdflags, ldBuildmode)
  1270  		if p != nil {
  1271  			fmt.Fprintf(h, "linkflags %q\n", p.Internal.Ldflags)
  1272  		}
  1273  
  1274  		// GOARM, GOMIPS, etc.
  1275  		key, val := cfg.GetArchEnv()
  1276  		fmt.Fprintf(h, "%s=%s\n", key, val)
  1277  
  1278  		if goexperiment := buildcfg.GOEXPERIMENT(); goexperiment != "" {
  1279  			fmt.Fprintf(h, "GOEXPERIMENT=%q\n", goexperiment)
  1280  		}
  1281  
  1282  		// The linker writes source file paths that say GOROOT_FINAL, but
  1283  		// only if -trimpath is not specified (see ld() in gc.go).
  1284  		gorootFinal := cfg.GOROOT_FINAL
  1285  		if cfg.BuildTrimpath {
  1286  			gorootFinal = trimPathGoRootFinal
  1287  		}
  1288  		fmt.Fprintf(h, "GOROOT=%s\n", gorootFinal)
  1289  
  1290  		// GO_EXTLINK_ENABLED controls whether the external linker is used.
  1291  		fmt.Fprintf(h, "GO_EXTLINK_ENABLED=%s\n", cfg.Getenv("GO_EXTLINK_ENABLED"))
  1292  
  1293  		// TODO(rsc): Do cgo settings and flags need to be included?
  1294  		// Or external linker settings and flags?
  1295  
  1296  	case "gccgo":
  1297  		id, err := b.gccToolID(BuildToolchain.linker(), "go")
  1298  		if err != nil {
  1299  			base.Fatalf("%v", err)
  1300  		}
  1301  		fmt.Fprintf(h, "link %s %s\n", id, ldBuildmode)
  1302  		// TODO(iant): Should probably include cgo flags here.
  1303  	}
  1304  }
  1305  
  1306  // link is the action for linking a single command.
  1307  // Note that any new influence on this logic must be reported in b.linkActionID above as well.
  1308  func (b *Builder) link(ctx context.Context, a *Action) (err error) {
  1309  	if b.useCache(a, b.linkActionID(a), a.Package.Target) || b.IsCmdList {
  1310  		return nil
  1311  	}
  1312  	defer b.flushOutput(a)
  1313  
  1314  	if err := b.Mkdir(a.Objdir); err != nil {
  1315  		return err
  1316  	}
  1317  
  1318  	importcfg := a.Objdir + "importcfg.link"
  1319  	if err := b.writeLinkImportcfg(a, importcfg); err != nil {
  1320  		return err
  1321  	}
  1322  
  1323  	if err := allowInstall(a); err != nil {
  1324  		return err
  1325  	}
  1326  
  1327  	// make target directory
  1328  	dir, _ := filepath.Split(a.Target)
  1329  	if dir != "" {
  1330  		if err := b.Mkdir(dir); err != nil {
  1331  			return err
  1332  		}
  1333  	}
  1334  
  1335  	if err := BuildToolchain.ld(b, a, a.Target, importcfg, a.Deps[0].built); err != nil {
  1336  		return err
  1337  	}
  1338  
  1339  	// Update the binary with the final build ID.
  1340  	// But if OmitDebug is set, don't rewrite the binary, because we set OmitDebug
  1341  	// on binaries that we are going to run and then delete.
  1342  	// There's no point in doing work on such a binary.
  1343  	// Worse, opening the binary for write here makes it
  1344  	// essentially impossible to safely fork+exec due to a fundamental
  1345  	// incompatibility between ETXTBSY and threads on modern Unix systems.
  1346  	// See golang.org/issue/22220.
  1347  	// We still call updateBuildID to update a.buildID, which is important
  1348  	// for test result caching, but passing rewrite=false (final arg)
  1349  	// means we don't actually rewrite the binary, nor store the
  1350  	// result into the cache. That's probably a net win:
  1351  	// less cache space wasted on large binaries we are not likely to
  1352  	// need again. (On the other hand it does make repeated go test slower.)
  1353  	// It also makes repeated go run slower, which is a win in itself:
  1354  	// we don't want people to treat go run like a scripting environment.
  1355  	if err := b.updateBuildID(a, a.Target, !a.Package.Internal.OmitDebug); err != nil {
  1356  		return err
  1357  	}
  1358  
  1359  	a.built = a.Target
  1360  	return nil
  1361  }
  1362  
  1363  func (b *Builder) writeLinkImportcfg(a *Action, file string) error {
  1364  	// Prepare Go import cfg.
  1365  	var icfg bytes.Buffer
  1366  	for _, a1 := range a.Deps {
  1367  		p1 := a1.Package
  1368  		if p1 == nil {
  1369  			continue
  1370  		}
  1371  		fmt.Fprintf(&icfg, "packagefile %s=%s\n", p1.ImportPath, a1.built)
  1372  		if p1.Shlib != "" {
  1373  			fmt.Fprintf(&icfg, "packageshlib %s=%s\n", p1.ImportPath, p1.Shlib)
  1374  		}
  1375  	}
  1376  	return b.writeFile(file, icfg.Bytes())
  1377  }
  1378  
  1379  // PkgconfigCmd returns a pkg-config binary name
  1380  // defaultPkgConfig is defined in zdefaultcc.go, written by cmd/dist.
  1381  func (b *Builder) PkgconfigCmd() string {
  1382  	return envList("PKG_CONFIG", cfg.DefaultPkgConfig)[0]
  1383  }
  1384  
  1385  // splitPkgConfigOutput parses the pkg-config output into a slice of
  1386  // flags. This implements the algorithm from pkgconf/libpkgconf/argvsplit.c.
  1387  func splitPkgConfigOutput(out []byte) ([]string, error) {
  1388  	if len(out) == 0 {
  1389  		return nil, nil
  1390  	}
  1391  	var flags []string
  1392  	flag := make([]byte, 0, len(out))
  1393  	escaped := false
  1394  	quote := byte(0)
  1395  
  1396  	for _, c := range out {
  1397  		if escaped {
  1398  			if quote != 0 {
  1399  				switch c {
  1400  				case '$', '`', '"', '\\':
  1401  				default:
  1402  					flag = append(flag, '\\')
  1403  				}
  1404  				flag = append(flag, c)
  1405  			} else {
  1406  				flag = append(flag, c)
  1407  			}
  1408  			escaped = false
  1409  		} else if quote != 0 {
  1410  			if c == quote {
  1411  				quote = 0
  1412  			} else {
  1413  				switch c {
  1414  				case '\\':
  1415  					escaped = true
  1416  				default:
  1417  					flag = append(flag, c)
  1418  				}
  1419  			}
  1420  		} else if strings.IndexByte(" \t\n\v\f\r", c) < 0 {
  1421  			switch c {
  1422  			case '\\':
  1423  				escaped = true
  1424  			case '\'', '"':
  1425  				quote = c
  1426  			default:
  1427  				flag = append(flag, c)
  1428  			}
  1429  		} else if len(flag) != 0 {
  1430  			flags = append(flags, string(flag))
  1431  			flag = flag[:0]
  1432  		}
  1433  	}
  1434  	if escaped {
  1435  		return nil, errors.New("broken character escaping in pkgconf output ")
  1436  	}
  1437  	if quote != 0 {
  1438  		return nil, errors.New("unterminated quoted string in pkgconf output ")
  1439  	} else if len(flag) != 0 {
  1440  		flags = append(flags, string(flag))
  1441  	}
  1442  
  1443  	return flags, nil
  1444  }
  1445  
  1446  // Calls pkg-config if needed and returns the cflags/ldflags needed to build the package.
  1447  func (b *Builder) getPkgConfigFlags(p *load.Package) (cflags, ldflags []string, err error) {
  1448  	if pcargs := p.CgoPkgConfig; len(pcargs) > 0 {
  1449  		// pkg-config permits arguments to appear anywhere in
  1450  		// the command line. Move them all to the front, before --.
  1451  		var pcflags []string
  1452  		var pkgs []string
  1453  		for _, pcarg := range pcargs {
  1454  			if pcarg == "--" {
  1455  				// We're going to add our own "--" argument.
  1456  			} else if strings.HasPrefix(pcarg, "--") {
  1457  				pcflags = append(pcflags, pcarg)
  1458  			} else {
  1459  				pkgs = append(pkgs, pcarg)
  1460  			}
  1461  		}
  1462  		for _, pkg := range pkgs {
  1463  			if !load.SafeArg(pkg) {
  1464  				return nil, nil, fmt.Errorf("invalid pkg-config package name: %s", pkg)
  1465  			}
  1466  		}
  1467  		var out []byte
  1468  		out, err = b.runOut(nil, p.Dir, nil, b.PkgconfigCmd(), "--cflags", pcflags, "--", pkgs)
  1469  		if err != nil {
  1470  			b.showOutput(nil, p.Dir, b.PkgconfigCmd()+" --cflags "+strings.Join(pcflags, " ")+" -- "+strings.Join(pkgs, " "), string(out))
  1471  			b.Print(err.Error() + "\n")
  1472  			return nil, nil, errPrintedOutput
  1473  		}
  1474  		if len(out) > 0 {
  1475  			cflags, err = splitPkgConfigOutput(out)
  1476  			if err != nil {
  1477  				return nil, nil, err
  1478  			}
  1479  			if err := checkCompilerFlags("CFLAGS", "pkg-config --cflags", cflags); err != nil {
  1480  				return nil, nil, err
  1481  			}
  1482  		}
  1483  		out, err = b.runOut(nil, p.Dir, nil, b.PkgconfigCmd(), "--libs", pcflags, "--", pkgs)
  1484  		if err != nil {
  1485  			b.showOutput(nil, p.Dir, b.PkgconfigCmd()+" --libs "+strings.Join(pcflags, " ")+" -- "+strings.Join(pkgs, " "), string(out))
  1486  			b.Print(err.Error() + "\n")
  1487  			return nil, nil, errPrintedOutput
  1488  		}
  1489  		if len(out) > 0 {
  1490  			ldflags = strings.Fields(string(out))
  1491  			if err := checkLinkerFlags("LDFLAGS", "pkg-config --libs", ldflags); err != nil {
  1492  				return nil, nil, err
  1493  			}
  1494  		}
  1495  	}
  1496  
  1497  	return
  1498  }
  1499  
  1500  func (b *Builder) installShlibname(ctx context.Context, a *Action) error {
  1501  	if err := allowInstall(a); err != nil {
  1502  		return err
  1503  	}
  1504  
  1505  	// TODO: BuildN
  1506  	a1 := a.Deps[0]
  1507  	err := os.WriteFile(a.Target, []byte(filepath.Base(a1.Target)+"\n"), 0666)
  1508  	if err != nil {
  1509  		return err
  1510  	}
  1511  	if cfg.BuildX {
  1512  		b.Showcmd("", "echo '%s' > %s # internal", filepath.Base(a1.Target), a.Target)
  1513  	}
  1514  	return nil
  1515  }
  1516  
  1517  func (b *Builder) linkSharedActionID(a *Action) cache.ActionID {
  1518  	h := cache.NewHash("linkShared")
  1519  
  1520  	// Toolchain-independent configuration.
  1521  	fmt.Fprintf(h, "linkShared\n")
  1522  	fmt.Fprintf(h, "goos %s goarch %s\n", cfg.Goos, cfg.Goarch)
  1523  
  1524  	// Toolchain-dependent configuration, shared with b.linkActionID.
  1525  	b.printLinkerConfig(h, nil)
  1526  
  1527  	// Input files.
  1528  	for _, a1 := range a.Deps {
  1529  		p1 := a1.Package
  1530  		if a1.built == "" {
  1531  			continue
  1532  		}
  1533  		if p1 != nil {
  1534  			fmt.Fprintf(h, "packagefile %s=%s\n", p1.ImportPath, contentID(b.buildID(a1.built)))
  1535  			if p1.Shlib != "" {
  1536  				fmt.Fprintf(h, "packageshlib %s=%s\n", p1.ImportPath, contentID(b.buildID(p1.Shlib)))
  1537  			}
  1538  		}
  1539  	}
  1540  	// Files named on command line are special.
  1541  	for _, a1 := range a.Deps[0].Deps {
  1542  		p1 := a1.Package
  1543  		fmt.Fprintf(h, "top %s=%s\n", p1.ImportPath, contentID(b.buildID(a1.built)))
  1544  	}
  1545  
  1546  	return h.Sum()
  1547  }
  1548  
  1549  func (b *Builder) linkShared(ctx context.Context, a *Action) (err error) {
  1550  	if b.useCache(a, b.linkSharedActionID(a), a.Target) || b.IsCmdList {
  1551  		return nil
  1552  	}
  1553  	defer b.flushOutput(a)
  1554  
  1555  	if err := allowInstall(a); err != nil {
  1556  		return err
  1557  	}
  1558  
  1559  	if err := b.Mkdir(a.Objdir); err != nil {
  1560  		return err
  1561  	}
  1562  
  1563  	importcfg := a.Objdir + "importcfg.link"
  1564  	if err := b.writeLinkImportcfg(a, importcfg); err != nil {
  1565  		return err
  1566  	}
  1567  
  1568  	// TODO(rsc): There is a missing updateBuildID here,
  1569  	// but we have to decide where to store the build ID in these files.
  1570  	a.built = a.Target
  1571  	return BuildToolchain.ldShared(b, a, a.Deps[0].Deps, a.Target, importcfg, a.Deps)
  1572  }
  1573  
  1574  // BuildInstallFunc is the action for installing a single package or executable.
  1575  func BuildInstallFunc(b *Builder, ctx context.Context, a *Action) (err error) {
  1576  	defer func() {
  1577  		if err != nil && err != errPrintedOutput {
  1578  			// a.Package == nil is possible for the go install -buildmode=shared
  1579  			// action that installs libmangledname.so, which corresponds to
  1580  			// a list of packages, not just one.
  1581  			sep, path := "", ""
  1582  			if a.Package != nil {
  1583  				sep, path = " ", a.Package.ImportPath
  1584  			}
  1585  			err = fmt.Errorf("go %s%s%s: %v", cfg.CmdName, sep, path, err)
  1586  		}
  1587  	}()
  1588  
  1589  	a1 := a.Deps[0]
  1590  	a.buildID = a1.buildID
  1591  	if a.json != nil {
  1592  		a.json.BuildID = a.buildID
  1593  	}
  1594  
  1595  	// If we are using the eventual install target as an up-to-date
  1596  	// cached copy of the thing we built, then there's no need to
  1597  	// copy it into itself (and that would probably fail anyway).
  1598  	// In this case a1.built == a.Target because a1.built == p.Target,
  1599  	// so the built target is not in the a1.Objdir tree that b.cleanup(a1) removes.
  1600  	if a1.built == a.Target {
  1601  		a.built = a.Target
  1602  		if !a.buggyInstall {
  1603  			b.cleanup(a1)
  1604  		}
  1605  		// Whether we're smart enough to avoid a complete rebuild
  1606  		// depends on exactly what the staleness and rebuild algorithms
  1607  		// are, as well as potentially the state of the Go build cache.
  1608  		// We don't really want users to be able to infer (or worse start depending on)
  1609  		// those details from whether the modification time changes during
  1610  		// "go install", so do a best-effort update of the file times to make it
  1611  		// look like we rewrote a.Target even if we did not. Updating the mtime
  1612  		// may also help other mtime-based systems that depend on our
  1613  		// previous mtime updates that happened more often.
  1614  		// This is still not perfect - we ignore the error result, and if the file was
  1615  		// unwritable for some reason then pretending to have written it is also
  1616  		// confusing - but it's probably better than not doing the mtime update.
  1617  		//
  1618  		// But don't do that for the special case where building an executable
  1619  		// with -linkshared implicitly installs all its dependent libraries.
  1620  		// We want to hide that awful detail as much as possible, so don't
  1621  		// advertise it by touching the mtimes (usually the libraries are up
  1622  		// to date).
  1623  		if !a.buggyInstall && !b.IsCmdList {
  1624  			if cfg.BuildN {
  1625  				b.Showcmd("", "touch %s", a.Target)
  1626  			} else if err := allowInstall(a); err == nil {
  1627  				now := time.Now()
  1628  				os.Chtimes(a.Target, now, now)
  1629  			}
  1630  		}
  1631  		return nil
  1632  	}
  1633  
  1634  	// If we're building for go list -export,
  1635  	// never install anything; just keep the cache reference.
  1636  	if b.IsCmdList {
  1637  		a.built = a1.built
  1638  		return nil
  1639  	}
  1640  	if err := allowInstall(a); err != nil {
  1641  		return err
  1642  	}
  1643  
  1644  	if err := b.Mkdir(a.Objdir); err != nil {
  1645  		return err
  1646  	}
  1647  
  1648  	perm := fs.FileMode(0666)
  1649  	if a1.Mode == "link" {
  1650  		switch cfg.BuildBuildmode {
  1651  		case "c-archive", "c-shared", "plugin":
  1652  		default:
  1653  			perm = 0777
  1654  		}
  1655  	}
  1656  
  1657  	// make target directory
  1658  	dir, _ := filepath.Split(a.Target)
  1659  	if dir != "" {
  1660  		if err := b.Mkdir(dir); err != nil {
  1661  			return err
  1662  		}
  1663  	}
  1664  
  1665  	if !a.buggyInstall {
  1666  		defer b.cleanup(a1)
  1667  	}
  1668  
  1669  	return b.moveOrCopyFile(a.Target, a1.built, perm, false)
  1670  }
  1671  
  1672  // allowInstall returns a non-nil error if this invocation of the go command is
  1673  // allowed to install a.Target.
  1674  //
  1675  // (The build of cmd/go running under its own test is forbidden from installing
  1676  // to its original GOROOT.)
  1677  var allowInstall = func(*Action) error { return nil }
  1678  
  1679  // cleanup removes a's object dir to keep the amount of
  1680  // on-disk garbage down in a large build. On an operating system
  1681  // with aggressive buffering, cleaning incrementally like
  1682  // this keeps the intermediate objects from hitting the disk.
  1683  func (b *Builder) cleanup(a *Action) {
  1684  	if !cfg.BuildWork {
  1685  		if cfg.BuildX {
  1686  			// Don't say we are removing the directory if
  1687  			// we never created it.
  1688  			if _, err := os.Stat(a.Objdir); err == nil || cfg.BuildN {
  1689  				b.Showcmd("", "rm -r %s", a.Objdir)
  1690  			}
  1691  		}
  1692  		os.RemoveAll(a.Objdir)
  1693  	}
  1694  }
  1695  
  1696  // moveOrCopyFile is like 'mv src dst' or 'cp src dst'.
  1697  func (b *Builder) moveOrCopyFile(dst, src string, perm fs.FileMode, force bool) error {
  1698  	if cfg.BuildN {
  1699  		b.Showcmd("", "mv %s %s", src, dst)
  1700  		return nil
  1701  	}
  1702  
  1703  	// If we can update the mode and rename to the dst, do it.
  1704  	// Otherwise fall back to standard copy.
  1705  
  1706  	// If the source is in the build cache, we need to copy it.
  1707  	if strings.HasPrefix(src, cache.DefaultDir()) {
  1708  		return b.copyFile(dst, src, perm, force)
  1709  	}
  1710  
  1711  	// On Windows, always copy the file, so that we respect the NTFS
  1712  	// permissions of the parent folder. https://golang.org/issue/22343.
  1713  	// What matters here is not cfg.Goos (the system we are building
  1714  	// for) but runtime.GOOS (the system we are building on).
  1715  	if runtime.GOOS == "windows" {
  1716  		return b.copyFile(dst, src, perm, force)
  1717  	}
  1718  
  1719  	// If the destination directory has the group sticky bit set,
  1720  	// we have to copy the file to retain the correct permissions.
  1721  	// https://golang.org/issue/18878
  1722  	if fi, err := os.Stat(filepath.Dir(dst)); err == nil {
  1723  		if fi.IsDir() && (fi.Mode()&fs.ModeSetgid) != 0 {
  1724  			return b.copyFile(dst, src, perm, force)
  1725  		}
  1726  	}
  1727  
  1728  	// The perm argument is meant to be adjusted according to umask,
  1729  	// but we don't know what the umask is.
  1730  	// Create a dummy file to find out.
  1731  	// This avoids build tags and works even on systems like Plan 9
  1732  	// where the file mask computation incorporates other information.
  1733  	mode := perm
  1734  	f, err := os.OpenFile(filepath.Clean(dst)+"-go-tmp-umask", os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm)
  1735  	if err == nil {
  1736  		fi, err := f.Stat()
  1737  		if err == nil {
  1738  			mode = fi.Mode() & 0777
  1739  		}
  1740  		name := f.Name()
  1741  		f.Close()
  1742  		os.Remove(name)
  1743  	}
  1744  
  1745  	if err := os.Chmod(src, mode); err == nil {
  1746  		if err := os.Rename(src, dst); err == nil {
  1747  			if cfg.BuildX {
  1748  				b.Showcmd("", "mv %s %s", src, dst)
  1749  			}
  1750  			return nil
  1751  		}
  1752  	}
  1753  
  1754  	return b.copyFile(dst, src, perm, force)
  1755  }
  1756  
  1757  // copyFile is like 'cp src dst'.
  1758  func (b *Builder) copyFile(dst, src string, perm fs.FileMode, force bool) error {
  1759  	if cfg.BuildN || cfg.BuildX {
  1760  		b.Showcmd("", "cp %s %s", src, dst)
  1761  		if cfg.BuildN {
  1762  			return nil
  1763  		}
  1764  	}
  1765  
  1766  	sf, err := os.Open(src)
  1767  	if err != nil {
  1768  		return err
  1769  	}
  1770  	defer sf.Close()
  1771  
  1772  	// Be careful about removing/overwriting dst.
  1773  	// Do not remove/overwrite if dst exists and is a directory
  1774  	// or a non-empty non-object file.
  1775  	if fi, err := os.Stat(dst); err == nil {
  1776  		if fi.IsDir() {
  1777  			return fmt.Errorf("build output %q already exists and is a directory", dst)
  1778  		}
  1779  		if !force && fi.Mode().IsRegular() && fi.Size() != 0 && !isObject(dst) {
  1780  			return fmt.Errorf("build output %q already exists and is not an object file", dst)
  1781  		}
  1782  	}
  1783  
  1784  	// On Windows, remove lingering ~ file from last attempt.
  1785  	if base.ToolIsWindows {
  1786  		if _, err := os.Stat(dst + "~"); err == nil {
  1787  			os.Remove(dst + "~")
  1788  		}
  1789  	}
  1790  
  1791  	mayberemovefile(dst)
  1792  	df, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
  1793  	if err != nil && base.ToolIsWindows {
  1794  		// Windows does not allow deletion of a binary file
  1795  		// while it is executing. Try to move it out of the way.
  1796  		// If the move fails, which is likely, we'll try again the
  1797  		// next time we do an install of this binary.
  1798  		if err := os.Rename(dst, dst+"~"); err == nil {
  1799  			os.Remove(dst + "~")
  1800  		}
  1801  		df, err = os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
  1802  	}
  1803  	if err != nil {
  1804  		return fmt.Errorf("copying %s: %w", src, err) // err should already refer to dst
  1805  	}
  1806  
  1807  	_, err = io.Copy(df, sf)
  1808  	df.Close()
  1809  	if err != nil {
  1810  		mayberemovefile(dst)
  1811  		return fmt.Errorf("copying %s to %s: %v", src, dst, err)
  1812  	}
  1813  	return nil
  1814  }
  1815  
  1816  // writeFile writes the text to file.
  1817  func (b *Builder) writeFile(file string, text []byte) error {
  1818  	if cfg.BuildN || cfg.BuildX {
  1819  		b.Showcmd("", "cat >%s << 'EOF' # internal\n%sEOF", file, text)
  1820  	}
  1821  	if cfg.BuildN {
  1822  		return nil
  1823  	}
  1824  	return os.WriteFile(file, text, 0666)
  1825  }
  1826  
  1827  // Install the cgo export header file, if there is one.
  1828  func (b *Builder) installHeader(ctx context.Context, a *Action) error {
  1829  	src := a.Objdir + "_cgo_install.h"
  1830  	if _, err := os.Stat(src); os.IsNotExist(err) {
  1831  		// If the file does not exist, there are no exported
  1832  		// functions, and we do not install anything.
  1833  		// TODO(rsc): Once we know that caching is rebuilding
  1834  		// at the right times (not missing rebuilds), here we should
  1835  		// probably delete the installed header, if any.
  1836  		if cfg.BuildX {
  1837  			b.Showcmd("", "# %s not created", src)
  1838  		}
  1839  		return nil
  1840  	}
  1841  
  1842  	if err := allowInstall(a); err != nil {
  1843  		return err
  1844  	}
  1845  
  1846  	dir, _ := filepath.Split(a.Target)
  1847  	if dir != "" {
  1848  		if err := b.Mkdir(dir); err != nil {
  1849  			return err
  1850  		}
  1851  	}
  1852  
  1853  	return b.moveOrCopyFile(a.Target, src, 0666, true)
  1854  }
  1855  
  1856  // cover runs, in effect,
  1857  //	go tool cover -mode=b.coverMode -var="varName" -o dst.go src.go
  1858  func (b *Builder) cover(a *Action, dst, src string, varName string) error {
  1859  	return b.run(a, a.Objdir, "cover "+a.Package.ImportPath, nil,
  1860  		cfg.BuildToolexec,
  1861  		base.Tool("cover"),
  1862  		"-mode", a.Package.Internal.CoverMode,
  1863  		"-var", varName,
  1864  		"-o", dst,
  1865  		src)
  1866  }
  1867  
  1868  var objectMagic = [][]byte{
  1869  	{'!', '<', 'a', 'r', 'c', 'h', '>', '\n'}, // Package archive
  1870  	{'<', 'b', 'i', 'g', 'a', 'f', '>', '\n'}, // Package AIX big archive
  1871  	{'\x7F', 'E', 'L', 'F'},                   // ELF
  1872  	{0xFE, 0xED, 0xFA, 0xCE},                  // Mach-O big-endian 32-bit
  1873  	{0xFE, 0xED, 0xFA, 0xCF},                  // Mach-O big-endian 64-bit
  1874  	{0xCE, 0xFA, 0xED, 0xFE},                  // Mach-O little-endian 32-bit
  1875  	{0xCF, 0xFA, 0xED, 0xFE},                  // Mach-O little-endian 64-bit
  1876  	{0x4d, 0x5a, 0x90, 0x00, 0x03, 0x00},      // PE (Windows) as generated by 6l/8l and gcc
  1877  	{0x4d, 0x5a, 0x78, 0x00, 0x01, 0x00},      // PE (Windows) as generated by llvm for dll
  1878  	{0x00, 0x00, 0x01, 0xEB},                  // Plan 9 i386
  1879  	{0x00, 0x00, 0x8a, 0x97},                  // Plan 9 amd64
  1880  	{0x00, 0x00, 0x06, 0x47},                  // Plan 9 arm
  1881  	{0x00, 0x61, 0x73, 0x6D},                  // WASM
  1882  	{0x01, 0xDF},                              // XCOFF 32bit
  1883  	{0x01, 0xF7},                              // XCOFF 64bit
  1884  }
  1885  
  1886  func isObject(s string) bool {
  1887  	f, err := os.Open(s)
  1888  	if err != nil {
  1889  		return false
  1890  	}
  1891  	defer f.Close()
  1892  	buf := make([]byte, 64)
  1893  	io.ReadFull(f, buf)
  1894  	for _, magic := range objectMagic {
  1895  		if bytes.HasPrefix(buf, magic) {
  1896  			return true
  1897  		}
  1898  	}
  1899  	return false
  1900  }
  1901  
  1902  // mayberemovefile removes a file only if it is a regular file
  1903  // When running as a user with sufficient privileges, we may delete
  1904  // even device files, for example, which is not intended.
  1905  func mayberemovefile(s string) {
  1906  	if fi, err := os.Lstat(s); err == nil && !fi.Mode().IsRegular() {
  1907  		return
  1908  	}
  1909  	os.Remove(s)
  1910  }
  1911  
  1912  // fmtcmd formats a command in the manner of fmt.Sprintf but also:
  1913  //
  1914  //	If dir is non-empty and the script is not in dir right now,
  1915  //	fmtcmd inserts "cd dir\n" before the command.
  1916  //
  1917  //	fmtcmd replaces the value of b.WorkDir with $WORK.
  1918  //	fmtcmd replaces the value of goroot with $GOROOT.
  1919  //	fmtcmd replaces the value of b.gobin with $GOBIN.
  1920  //
  1921  //	fmtcmd replaces the name of the current directory with dot (.)
  1922  //	but only when it is at the beginning of a space-separated token.
  1923  //
  1924  func (b *Builder) fmtcmd(dir string, format string, args ...interface{}) string {
  1925  	cmd := fmt.Sprintf(format, args...)
  1926  	if dir != "" && dir != "/" {
  1927  		dot := " ."
  1928  		if dir[len(dir)-1] == filepath.Separator {
  1929  			dot += string(filepath.Separator)
  1930  		}
  1931  		cmd = strings.ReplaceAll(" "+cmd, " "+dir, dot)[1:]
  1932  		if b.scriptDir != dir {
  1933  			b.scriptDir = dir
  1934  			cmd = "cd " + dir + "\n" + cmd
  1935  		}
  1936  	}
  1937  	if b.WorkDir != "" {
  1938  		cmd = strings.ReplaceAll(cmd, b.WorkDir, "$WORK")
  1939  		escaped := strconv.Quote(b.WorkDir)
  1940  		escaped = escaped[1 : len(escaped)-1] // strip quote characters
  1941  		if escaped != b.WorkDir {
  1942  			cmd = strings.ReplaceAll(cmd, escaped, "$WORK")
  1943  		}
  1944  	}
  1945  	return cmd
  1946  }
  1947  
  1948  // showcmd prints the given command to standard output
  1949  // for the implementation of -n or -x.
  1950  func (b *Builder) Showcmd(dir string, format string, args ...interface{}) {
  1951  	b.output.Lock()
  1952  	defer b.output.Unlock()
  1953  	b.Print(b.fmtcmd(dir, format, args...) + "\n")
  1954  }
  1955  
  1956  // showOutput prints "# desc" followed by the given output.
  1957  // The output is expected to contain references to 'dir', usually
  1958  // the source directory for the package that has failed to build.
  1959  // showOutput rewrites mentions of dir with a relative path to dir
  1960  // when the relative path is shorter. This is usually more pleasant.
  1961  // For example, if fmt doesn't compile and we are in src/html,
  1962  // the output is
  1963  //
  1964  //	$ go build
  1965  //	# fmt
  1966  //	../fmt/print.go:1090: undefined: asdf
  1967  //	$
  1968  //
  1969  // instead of
  1970  //
  1971  //	$ go build
  1972  //	# fmt
  1973  //	/usr/gopher/go/src/fmt/print.go:1090: undefined: asdf
  1974  //	$
  1975  //
  1976  // showOutput also replaces references to the work directory with $WORK.
  1977  //
  1978  // If a is not nil and a.output is not nil, showOutput appends to that slice instead of
  1979  // printing to b.Print.
  1980  //
  1981  func (b *Builder) showOutput(a *Action, dir, desc, out string) {
  1982  	prefix := "# " + desc
  1983  	suffix := "\n" + out
  1984  	if reldir := base.ShortPath(dir); reldir != dir {
  1985  		suffix = strings.ReplaceAll(suffix, " "+dir, " "+reldir)
  1986  		suffix = strings.ReplaceAll(suffix, "\n"+dir, "\n"+reldir)
  1987  	}
  1988  	suffix = strings.ReplaceAll(suffix, " "+b.WorkDir, " $WORK")
  1989  
  1990  	if a != nil && a.output != nil {
  1991  		a.output = append(a.output, prefix...)
  1992  		a.output = append(a.output, suffix...)
  1993  		return
  1994  	}
  1995  
  1996  	b.output.Lock()
  1997  	defer b.output.Unlock()
  1998  	b.Print(prefix, suffix)
  1999  }
  2000  
  2001  // errPrintedOutput is a special error indicating that a command failed
  2002  // but that it generated output as well, and that output has already
  2003  // been printed, so there's no point showing 'exit status 1' or whatever
  2004  // the wait status was. The main executor, builder.do, knows not to
  2005  // print this error.
  2006  var errPrintedOutput = errors.New("already printed output - no need to show error")
  2007  
  2008  var cgoLine = lazyregexp.New(`\[[^\[\]]+\.(cgo1|cover)\.go:[0-9]+(:[0-9]+)?\]`)
  2009  var cgoTypeSigRe = lazyregexp.New(`\b_C2?(type|func|var|macro)_\B`)
  2010  
  2011  // run runs the command given by cmdline in the directory dir.
  2012  // If the command fails, run prints information about the failure
  2013  // and returns a non-nil error.
  2014  func (b *Builder) run(a *Action, dir string, desc string, env []string, cmdargs ...interface{}) error {
  2015  	out, err := b.runOut(a, dir, env, cmdargs...)
  2016  	if len(out) > 0 {
  2017  		if desc == "" {
  2018  			desc = b.fmtcmd(dir, "%s", strings.Join(str.StringList(cmdargs...), " "))
  2019  		}
  2020  		b.showOutput(a, dir, desc, b.processOutput(out))
  2021  		if err != nil {
  2022  			err = errPrintedOutput
  2023  		}
  2024  	}
  2025  	return err
  2026  }
  2027  
  2028  // processOutput prepares the output of runOut to be output to the console.
  2029  func (b *Builder) processOutput(out []byte) string {
  2030  	if out[len(out)-1] != '\n' {
  2031  		out = append(out, '\n')
  2032  	}
  2033  	messages := string(out)
  2034  	// Fix up output referring to cgo-generated code to be more readable.
  2035  	// Replace x.go:19[/tmp/.../x.cgo1.go:18] with x.go:19.
  2036  	// Replace *[100]_Ctype_foo with *[100]C.foo.
  2037  	// If we're using -x, assume we're debugging and want the full dump, so disable the rewrite.
  2038  	if !cfg.BuildX && cgoLine.MatchString(messages) {
  2039  		messages = cgoLine.ReplaceAllString(messages, "")
  2040  		messages = cgoTypeSigRe.ReplaceAllString(messages, "C.")
  2041  	}
  2042  	return messages
  2043  }
  2044  
  2045  // runOut runs the command given by cmdline in the directory dir.
  2046  // It returns the command output and any errors that occurred.
  2047  // It accumulates execution time in a.
  2048  func (b *Builder) runOut(a *Action, dir string, env []string, cmdargs ...interface{}) ([]byte, error) {
  2049  	cmdline := str.StringList(cmdargs...)
  2050  
  2051  	for _, arg := range cmdline {
  2052  		// GNU binutils commands, including gcc and gccgo, interpret an argument
  2053  		// @foo anywhere in the command line (even following --) as meaning
  2054  		// "read and insert arguments from the file named foo."
  2055  		// Don't say anything that might be misinterpreted that way.
  2056  		if strings.HasPrefix(arg, "@") {
  2057  			return nil, fmt.Errorf("invalid command-line argument %s in command: %s", arg, joinUnambiguously(cmdline))
  2058  		}
  2059  	}
  2060  
  2061  	if cfg.BuildN || cfg.BuildX {
  2062  		var envcmdline string
  2063  		for _, e := range env {
  2064  			if j := strings.IndexByte(e, '='); j != -1 {
  2065  				if strings.ContainsRune(e[j+1:], '\'') {
  2066  					envcmdline += fmt.Sprintf("%s=%q", e[:j], e[j+1:])
  2067  				} else {
  2068  					envcmdline += fmt.Sprintf("%s='%s'", e[:j], e[j+1:])
  2069  				}
  2070  				envcmdline += " "
  2071  			}
  2072  		}
  2073  		envcmdline += joinUnambiguously(cmdline)
  2074  		b.Showcmd(dir, "%s", envcmdline)
  2075  		if cfg.BuildN {
  2076  			return nil, nil
  2077  		}
  2078  	}
  2079  
  2080  	var buf bytes.Buffer
  2081  	cmd := exec.Command(cmdline[0], cmdline[1:]...)
  2082  	if cmd.Path != "" {
  2083  		cmd.Args[0] = cmd.Path
  2084  	}
  2085  	cmd.Stdout = &buf
  2086  	cmd.Stderr = &buf
  2087  	cleanup := passLongArgsInResponseFiles(cmd)
  2088  	defer cleanup()
  2089  	cmd.Dir = dir
  2090  	cmd.Env = base.AppendPWD(os.Environ(), cmd.Dir)
  2091  
  2092  	// Add the TOOLEXEC_IMPORTPATH environment variable for -toolexec tools.
  2093  	// It doesn't really matter if -toolexec isn't being used.
  2094  	// Note that a.Package.Desc is not really an import path,
  2095  	// but this is consistent with 'go list -f {{.ImportPath}}'.
  2096  	// Plus, it is useful to uniquely identify packages in 'go list -json'.
  2097  	if a != nil && a.Package != nil {
  2098  		cmd.Env = append(cmd.Env, "TOOLEXEC_IMPORTPATH="+a.Package.Desc())
  2099  	}
  2100  
  2101  	cmd.Env = append(cmd.Env, env...)
  2102  	start := time.Now()
  2103  	err := cmd.Run()
  2104  	if a != nil && a.json != nil {
  2105  		aj := a.json
  2106  		aj.Cmd = append(aj.Cmd, joinUnambiguously(cmdline))
  2107  		aj.CmdReal += time.Since(start)
  2108  		if ps := cmd.ProcessState; ps != nil {
  2109  			aj.CmdUser += ps.UserTime()
  2110  			aj.CmdSys += ps.SystemTime()
  2111  		}
  2112  	}
  2113  
  2114  	// err can be something like 'exit status 1'.
  2115  	// Add information about what program was running.
  2116  	// Note that if buf.Bytes() is non-empty, the caller usually
  2117  	// shows buf.Bytes() and does not print err at all, so the
  2118  	// prefix here does not make most output any more verbose.
  2119  	if err != nil {
  2120  		err = errors.New(cmdline[0] + ": " + err.Error())
  2121  	}
  2122  	return buf.Bytes(), err
  2123  }
  2124  
  2125  // joinUnambiguously prints the slice, quoting where necessary to make the
  2126  // output unambiguous.
  2127  // TODO: See issue 5279. The printing of commands needs a complete redo.
  2128  func joinUnambiguously(a []string) string {
  2129  	var buf bytes.Buffer
  2130  	for i, s := range a {
  2131  		if i > 0 {
  2132  			buf.WriteByte(' ')
  2133  		}
  2134  		q := strconv.Quote(s)
  2135  		// A gccgo command line can contain -( and -).
  2136  		// Make sure we quote them since they are special to the shell.
  2137  		// The trimpath argument can also contain > (part of =>) and ;. Quote those too.
  2138  		if s == "" || strings.ContainsAny(s, " ()>;") || len(q) > len(s)+2 {
  2139  			buf.WriteString(q)
  2140  		} else {
  2141  			buf.WriteString(s)
  2142  		}
  2143  	}
  2144  	return buf.String()
  2145  }
  2146  
  2147  // cCompilerEnv returns environment variables to set when running the
  2148  // C compiler. This is needed to disable escape codes in clang error
  2149  // messages that confuse tools like cgo.
  2150  func (b *Builder) cCompilerEnv() []string {
  2151  	return []string{"TERM=dumb"}
  2152  }
  2153  
  2154  // mkdir makes the named directory.
  2155  func (b *Builder) Mkdir(dir string) error {
  2156  	// Make Mkdir(a.Objdir) a no-op instead of an error when a.Objdir == "".
  2157  	if dir == "" {
  2158  		return nil
  2159  	}
  2160  
  2161  	b.exec.Lock()
  2162  	defer b.exec.Unlock()
  2163  	// We can be a little aggressive about being
  2164  	// sure directories exist. Skip repeated calls.
  2165  	if b.mkdirCache[dir] {
  2166  		return nil
  2167  	}
  2168  	b.mkdirCache[dir] = true
  2169  
  2170  	if cfg.BuildN || cfg.BuildX {
  2171  		b.Showcmd("", "mkdir -p %s", dir)
  2172  		if cfg.BuildN {
  2173  			return nil
  2174  		}
  2175  	}
  2176  
  2177  	if err := os.MkdirAll(dir, 0777); err != nil {
  2178  		return err
  2179  	}
  2180  	return nil
  2181  }
  2182  
  2183  // symlink creates a symlink newname -> oldname.
  2184  func (b *Builder) Symlink(oldname, newname string) error {
  2185  	// It's not an error to try to recreate an existing symlink.
  2186  	if link, err := os.Readlink(newname); err == nil && link == oldname {
  2187  		return nil
  2188  	}
  2189  
  2190  	if cfg.BuildN || cfg.BuildX {
  2191  		b.Showcmd("", "ln -s %s %s", oldname, newname)
  2192  		if cfg.BuildN {
  2193  			return nil
  2194  		}
  2195  	}
  2196  	return os.Symlink(oldname, newname)
  2197  }
  2198  
  2199  // mkAbs returns an absolute path corresponding to
  2200  // evaluating f in the directory dir.
  2201  // We always pass absolute paths of source files so that
  2202  // the error messages will include the full path to a file
  2203  // in need of attention.
  2204  func mkAbs(dir, f string) string {
  2205  	// Leave absolute paths alone.
  2206  	// Also, during -n mode we use the pseudo-directory $WORK
  2207  	// instead of creating an actual work directory that won't be used.
  2208  	// Leave paths beginning with $WORK alone too.
  2209  	if filepath.IsAbs(f) || strings.HasPrefix(f, "$WORK") {
  2210  		return f
  2211  	}
  2212  	return filepath.Join(dir, f)
  2213  }
  2214  
  2215  type toolchain interface {
  2216  	// gc runs the compiler in a specific directory on a set of files
  2217  	// and returns the name of the generated output file.
  2218  	gc(b *Builder, a *Action, archive string, importcfg, embedcfg []byte, symabis string, asmhdr bool, gofiles []string) (ofile string, out []byte, err error)
  2219  	// cc runs the toolchain's C compiler in a directory on a C file
  2220  	// to produce an output file.
  2221  	cc(b *Builder, a *Action, ofile, cfile string) error
  2222  	// asm runs the assembler in a specific directory on specific files
  2223  	// and returns a list of named output files.
  2224  	asm(b *Builder, a *Action, sfiles []string) ([]string, error)
  2225  	// symabis scans the symbol ABIs from sfiles and returns the
  2226  	// path to the output symbol ABIs file, or "" if none.
  2227  	symabis(b *Builder, a *Action, sfiles []string) (string, error)
  2228  	// pack runs the archive packer in a specific directory to create
  2229  	// an archive from a set of object files.
  2230  	// typically it is run in the object directory.
  2231  	pack(b *Builder, a *Action, afile string, ofiles []string) error
  2232  	// ld runs the linker to create an executable starting at mainpkg.
  2233  	ld(b *Builder, root *Action, out, importcfg, mainpkg string) error
  2234  	// ldShared runs the linker to create a shared library containing the pkgs built by toplevelactions
  2235  	ldShared(b *Builder, root *Action, toplevelactions []*Action, out, importcfg string, allactions []*Action) error
  2236  
  2237  	compiler() string
  2238  	linker() string
  2239  }
  2240  
  2241  type noToolchain struct{}
  2242  
  2243  func noCompiler() error {
  2244  	log.Fatalf("unknown compiler %q", cfg.BuildContext.Compiler)
  2245  	return nil
  2246  }
  2247  
  2248  func (noToolchain) compiler() string {
  2249  	noCompiler()
  2250  	return ""
  2251  }
  2252  
  2253  func (noToolchain) linker() string {
  2254  	noCompiler()
  2255  	return ""
  2256  }
  2257  
  2258  func (noToolchain) gc(b *Builder, a *Action, archive string, importcfg, embedcfg []byte, symabis string, asmhdr bool, gofiles []string) (ofile string, out []byte, err error) {
  2259  	return "", nil, noCompiler()
  2260  }
  2261  
  2262  func (noToolchain) asm(b *Builder, a *Action, sfiles []string) ([]string, error) {
  2263  	return nil, noCompiler()
  2264  }
  2265  
  2266  func (noToolchain) symabis(b *Builder, a *Action, sfiles []string) (string, error) {
  2267  	return "", noCompiler()
  2268  }
  2269  
  2270  func (noToolchain) pack(b *Builder, a *Action, afile string, ofiles []string) error {
  2271  	return noCompiler()
  2272  }
  2273  
  2274  func (noToolchain) ld(b *Builder, root *Action, out, importcfg, mainpkg string) error {
  2275  	return noCompiler()
  2276  }
  2277  
  2278  func (noToolchain) ldShared(b *Builder, root *Action, toplevelactions []*Action, out, importcfg string, allactions []*Action) error {
  2279  	return noCompiler()
  2280  }
  2281  
  2282  func (noToolchain) cc(b *Builder, a *Action, ofile, cfile string) error {
  2283  	return noCompiler()
  2284  }
  2285  
  2286  // gcc runs the gcc C compiler to create an object from a single C file.
  2287  func (b *Builder) gcc(a *Action, p *load.Package, workdir, out string, flags []string, cfile string) error {
  2288  	return b.ccompile(a, p, out, flags, cfile, b.GccCmd(p.Dir, workdir))
  2289  }
  2290  
  2291  // gxx runs the g++ C++ compiler to create an object from a single C++ file.
  2292  func (b *Builder) gxx(a *Action, p *load.Package, workdir, out string, flags []string, cxxfile string) error {
  2293  	return b.ccompile(a, p, out, flags, cxxfile, b.GxxCmd(p.Dir, workdir))
  2294  }
  2295  
  2296  // gfortran runs the gfortran Fortran compiler to create an object from a single Fortran file.
  2297  func (b *Builder) gfortran(a *Action, p *load.Package, workdir, out string, flags []string, ffile string) error {
  2298  	return b.ccompile(a, p, out, flags, ffile, b.gfortranCmd(p.Dir, workdir))
  2299  }
  2300  
  2301  // ccompile runs the given C or C++ compiler and creates an object from a single source file.
  2302  func (b *Builder) ccompile(a *Action, p *load.Package, outfile string, flags []string, file string, compiler []string) error {
  2303  	file = mkAbs(p.Dir, file)
  2304  	desc := p.ImportPath
  2305  	outfile = mkAbs(p.Dir, outfile)
  2306  
  2307  	// Elide source directory paths if -trimpath or GOROOT_FINAL is set.
  2308  	// This is needed for source files (e.g., a .c file in a package directory).
  2309  	// TODO(golang.org/issue/36072): cgo also generates files with #line
  2310  	// directives pointing to the source directory. It should not generate those
  2311  	// when -trimpath is enabled.
  2312  	if b.gccSupportsFlag(compiler, "-fdebug-prefix-map=a=b") {
  2313  		if cfg.BuildTrimpath {
  2314  			// Keep in sync with Action.trimpath.
  2315  			// The trimmed paths are a little different, but we need to trim in the
  2316  			// same situations.
  2317  			var from, toPath string
  2318  			if m := p.Module; m != nil {
  2319  				from = m.Dir
  2320  				toPath = m.Path + "@" + m.Version
  2321  			} else {
  2322  				from = p.Dir
  2323  				toPath = p.ImportPath
  2324  			}
  2325  			// -fdebug-prefix-map requires an absolute "to" path (or it joins the path
  2326  			// with the working directory). Pick something that makes sense for the
  2327  			// target platform.
  2328  			var to string
  2329  			if cfg.BuildContext.GOOS == "windows" {
  2330  				to = filepath.Join(`\\_\_`, toPath)
  2331  			} else {
  2332  				to = filepath.Join("/_", toPath)
  2333  			}
  2334  			flags = append(flags[:len(flags):len(flags)], "-fdebug-prefix-map="+from+"="+to)
  2335  		} else if p.Goroot && cfg.GOROOT_FINAL != cfg.GOROOT {
  2336  			flags = append(flags[:len(flags):len(flags)], "-fdebug-prefix-map="+cfg.GOROOT+"="+cfg.GOROOT_FINAL)
  2337  		}
  2338  	}
  2339  
  2340  	overlayPath := file
  2341  	if p, ok := a.nonGoOverlay[overlayPath]; ok {
  2342  		overlayPath = p
  2343  	}
  2344  	output, err := b.runOut(a, filepath.Dir(overlayPath), b.cCompilerEnv(), compiler, flags, "-o", outfile, "-c", filepath.Base(overlayPath))
  2345  	if len(output) > 0 {
  2346  		// On FreeBSD 11, when we pass -g to clang 3.8 it
  2347  		// invokes its internal assembler with -dwarf-version=2.
  2348  		// When it sees .section .note.GNU-stack, it warns
  2349  		// "DWARF2 only supports one section per compilation unit".
  2350  		// This warning makes no sense, since the section is empty,
  2351  		// but it confuses people.
  2352  		// We work around the problem by detecting the warning
  2353  		// and dropping -g and trying again.
  2354  		if bytes.Contains(output, []byte("DWARF2 only supports one section per compilation unit")) {
  2355  			newFlags := make([]string, 0, len(flags))
  2356  			for _, f := range flags {
  2357  				if !strings.HasPrefix(f, "-g") {
  2358  					newFlags = append(newFlags, f)
  2359  				}
  2360  			}
  2361  			if len(newFlags) < len(flags) {
  2362  				return b.ccompile(a, p, outfile, newFlags, file, compiler)
  2363  			}
  2364  		}
  2365  
  2366  		b.showOutput(a, p.Dir, desc, b.processOutput(output))
  2367  		if err != nil {
  2368  			err = errPrintedOutput
  2369  		} else if os.Getenv("GO_BUILDER_NAME") != "" {
  2370  			return errors.New("C compiler warning promoted to error on Go builders")
  2371  		}
  2372  	}
  2373  	return err
  2374  }
  2375  
  2376  // gccld runs the gcc linker to create an executable from a set of object files.
  2377  func (b *Builder) gccld(a *Action, p *load.Package, objdir, outfile string, flags []string, objs []string) error {
  2378  	var cmd []string
  2379  	if len(p.CXXFiles) > 0 || len(p.SwigCXXFiles) > 0 {
  2380  		cmd = b.GxxCmd(p.Dir, objdir)
  2381  	} else {
  2382  		cmd = b.GccCmd(p.Dir, objdir)
  2383  	}
  2384  
  2385  	cmdargs := []interface{}{cmd, "-o", outfile, objs, flags}
  2386  	dir := p.Dir
  2387  	out, err := b.runOut(a, base.Cwd(), b.cCompilerEnv(), cmdargs...)
  2388  
  2389  	if len(out) > 0 {
  2390  		// Filter out useless linker warnings caused by bugs outside Go.
  2391  		// See also cmd/link/internal/ld's hostlink method.
  2392  		var save [][]byte
  2393  		var skipLines int
  2394  		for _, line := range bytes.SplitAfter(out, []byte("\n")) {
  2395  			// golang.org/issue/26073 - Apple Xcode bug
  2396  			if bytes.Contains(line, []byte("ld: warning: text-based stub file")) {
  2397  				continue
  2398  			}
  2399  
  2400  			if skipLines > 0 {
  2401  				skipLines--
  2402  				continue
  2403  			}
  2404  
  2405  			// Remove duplicate main symbol with runtime/cgo on AIX.
  2406  			// With runtime/cgo, two main are available:
  2407  			// One is generated by cgo tool with {return 0;}.
  2408  			// The other one is the main calling runtime.rt0_go
  2409  			// in runtime/cgo.
  2410  			// The second can't be used by cgo programs because
  2411  			// runtime.rt0_go is unknown to them.
  2412  			// Therefore, we let ld remove this main version
  2413  			// and used the cgo generated one.
  2414  			if p.ImportPath == "runtime/cgo" && bytes.Contains(line, []byte("ld: 0711-224 WARNING: Duplicate symbol: .main")) {
  2415  				skipLines = 1
  2416  				continue
  2417  			}
  2418  
  2419  			save = append(save, line)
  2420  		}
  2421  		out = bytes.Join(save, nil)
  2422  		if len(out) > 0 {
  2423  			b.showOutput(nil, dir, p.ImportPath, b.processOutput(out))
  2424  			if err != nil {
  2425  				err = errPrintedOutput
  2426  			}
  2427  		}
  2428  	}
  2429  	return err
  2430  }
  2431  
  2432  // Grab these before main helpfully overwrites them.
  2433  var (
  2434  	origCC  = cfg.Getenv("CC")
  2435  	origCXX = cfg.Getenv("CXX")
  2436  )
  2437  
  2438  // gccCmd returns a gcc command line prefix
  2439  // defaultCC is defined in zdefaultcc.go, written by cmd/dist.
  2440  func (b *Builder) GccCmd(incdir, workdir string) []string {
  2441  	return b.compilerCmd(b.ccExe(), incdir, workdir)
  2442  }
  2443  
  2444  // gxxCmd returns a g++ command line prefix
  2445  // defaultCXX is defined in zdefaultcc.go, written by cmd/dist.
  2446  func (b *Builder) GxxCmd(incdir, workdir string) []string {
  2447  	return b.compilerCmd(b.cxxExe(), incdir, workdir)
  2448  }
  2449  
  2450  // gfortranCmd returns a gfortran command line prefix.
  2451  func (b *Builder) gfortranCmd(incdir, workdir string) []string {
  2452  	return b.compilerCmd(b.fcExe(), incdir, workdir)
  2453  }
  2454  
  2455  // ccExe returns the CC compiler setting without all the extra flags we add implicitly.
  2456  func (b *Builder) ccExe() []string {
  2457  	return b.compilerExe(origCC, cfg.DefaultCC(cfg.Goos, cfg.Goarch))
  2458  }
  2459  
  2460  // cxxExe returns the CXX compiler setting without all the extra flags we add implicitly.
  2461  func (b *Builder) cxxExe() []string {
  2462  	return b.compilerExe(origCXX, cfg.DefaultCXX(cfg.Goos, cfg.Goarch))
  2463  }
  2464  
  2465  // fcExe returns the FC compiler setting without all the extra flags we add implicitly.
  2466  func (b *Builder) fcExe() []string {
  2467  	return b.compilerExe(cfg.Getenv("FC"), "gfortran")
  2468  }
  2469  
  2470  // compilerExe returns the compiler to use given an
  2471  // environment variable setting (the value not the name)
  2472  // and a default. The resulting slice is usually just the name
  2473  // of the compiler but can have additional arguments if they
  2474  // were present in the environment value.
  2475  // For example if CC="gcc -DGOPHER" then the result is ["gcc", "-DGOPHER"].
  2476  func (b *Builder) compilerExe(envValue string, def string) []string {
  2477  	compiler := strings.Fields(envValue)
  2478  	if len(compiler) == 0 {
  2479  		compiler = strings.Fields(def)
  2480  	}
  2481  	return compiler
  2482  }
  2483  
  2484  // compilerCmd returns a command line prefix for the given environment
  2485  // variable and using the default command when the variable is empty.
  2486  func (b *Builder) compilerCmd(compiler []string, incdir, workdir string) []string {
  2487  	// NOTE: env.go's mkEnv knows that the first three
  2488  	// strings returned are "gcc", "-I", incdir (and cuts them off).
  2489  	a := []string{compiler[0], "-I", incdir}
  2490  	a = append(a, compiler[1:]...)
  2491  
  2492  	// Definitely want -fPIC but on Windows gcc complains
  2493  	// "-fPIC ignored for target (all code is position independent)"
  2494  	if cfg.Goos != "windows" {
  2495  		a = append(a, "-fPIC")
  2496  	}
  2497  	a = append(a, b.gccArchArgs()...)
  2498  	// gcc-4.5 and beyond require explicit "-pthread" flag
  2499  	// for multithreading with pthread library.
  2500  	if cfg.BuildContext.CgoEnabled {
  2501  		switch cfg.Goos {
  2502  		case "windows":
  2503  			a = append(a, "-mthreads")
  2504  		default:
  2505  			a = append(a, "-pthread")
  2506  		}
  2507  	}
  2508  
  2509  	if cfg.Goos == "aix" {
  2510  		// mcmodel=large must always be enabled to allow large TOC.
  2511  		a = append(a, "-mcmodel=large")
  2512  	}
  2513  
  2514  	// disable ASCII art in clang errors, if possible
  2515  	if b.gccSupportsFlag(compiler, "-fno-caret-diagnostics") {
  2516  		a = append(a, "-fno-caret-diagnostics")
  2517  	}
  2518  	// clang is too smart about command-line arguments
  2519  	if b.gccSupportsFlag(compiler, "-Qunused-arguments") {
  2520  		a = append(a, "-Qunused-arguments")
  2521  	}
  2522  
  2523  	// disable word wrapping in error messages
  2524  	a = append(a, "-fmessage-length=0")
  2525  
  2526  	// Tell gcc not to include the work directory in object files.
  2527  	if b.gccSupportsFlag(compiler, "-fdebug-prefix-map=a=b") {
  2528  		if workdir == "" {
  2529  			workdir = b.WorkDir
  2530  		}
  2531  		workdir = strings.TrimSuffix(workdir, string(filepath.Separator))
  2532  		a = append(a, "-fdebug-prefix-map="+workdir+"=/tmp/go-build")
  2533  	}
  2534  
  2535  	// Tell gcc not to include flags in object files, which defeats the
  2536  	// point of -fdebug-prefix-map above.
  2537  	if b.gccSupportsFlag(compiler, "-gno-record-gcc-switches") {
  2538  		a = append(a, "-gno-record-gcc-switches")
  2539  	}
  2540  
  2541  	// On OS X, some of the compilers behave as if -fno-common
  2542  	// is always set, and the Mach-O linker in 6l/8l assumes this.
  2543  	// See https://golang.org/issue/3253.
  2544  	if cfg.Goos == "darwin" || cfg.Goos == "ios" {
  2545  		a = append(a, "-fno-common")
  2546  	}
  2547  
  2548  	return a
  2549  }
  2550  
  2551  // gccNoPie returns the flag to use to request non-PIE. On systems
  2552  // with PIE (position independent executables) enabled by default,
  2553  // -no-pie must be passed when doing a partial link with -Wl,-r.
  2554  // But -no-pie is not supported by all compilers, and clang spells it -nopie.
  2555  func (b *Builder) gccNoPie(linker []string) string {
  2556  	if b.gccSupportsFlag(linker, "-no-pie") {
  2557  		return "-no-pie"
  2558  	}
  2559  	if b.gccSupportsFlag(linker, "-nopie") {
  2560  		return "-nopie"
  2561  	}
  2562  	return ""
  2563  }
  2564  
  2565  // gccSupportsFlag checks to see if the compiler supports a flag.
  2566  func (b *Builder) gccSupportsFlag(compiler []string, flag string) bool {
  2567  	key := [2]string{compiler[0], flag}
  2568  
  2569  	b.exec.Lock()
  2570  	defer b.exec.Unlock()
  2571  	if b, ok := b.flagCache[key]; ok {
  2572  		return b
  2573  	}
  2574  	if b.flagCache == nil {
  2575  		b.flagCache = make(map[[2]string]bool)
  2576  	}
  2577  
  2578  	tmp := os.DevNull
  2579  	if runtime.GOOS == "windows" {
  2580  		f, err := os.CreateTemp(b.WorkDir, "")
  2581  		if err != nil {
  2582  			return false
  2583  		}
  2584  		f.Close()
  2585  		tmp = f.Name()
  2586  		defer os.Remove(tmp)
  2587  	}
  2588  
  2589  	// We used to write an empty C file, but that gets complicated with
  2590  	// go build -n. We tried using a file that does not exist, but that
  2591  	// fails on systems with GCC version 4.2.1; that is the last GPLv2
  2592  	// version of GCC, so some systems have frozen on it.
  2593  	// Now we pass an empty file on stdin, which should work at least for
  2594  	// GCC and clang.
  2595  	cmdArgs := str.StringList(compiler, flag, "-c", "-x", "c", "-", "-o", tmp)
  2596  	if cfg.BuildN || cfg.BuildX {
  2597  		b.Showcmd(b.WorkDir, "%s || true", joinUnambiguously(cmdArgs))
  2598  		if cfg.BuildN {
  2599  			return false
  2600  		}
  2601  	}
  2602  	cmd := exec.Command(cmdArgs[0], cmdArgs[1:]...)
  2603  	cmd.Dir = b.WorkDir
  2604  	cmd.Env = base.AppendPWD(os.Environ(), cmd.Dir)
  2605  	cmd.Env = append(cmd.Env, "LC_ALL=C")
  2606  	out, _ := cmd.CombinedOutput()
  2607  	// GCC says "unrecognized command line option".
  2608  	// clang says "unknown argument".
  2609  	// Older versions of GCC say "unrecognised debug output level".
  2610  	// For -fsplit-stack GCC says "'-fsplit-stack' is not supported".
  2611  	supported := !bytes.Contains(out, []byte("unrecognized")) &&
  2612  		!bytes.Contains(out, []byte("unknown")) &&
  2613  		!bytes.Contains(out, []byte("unrecognised")) &&
  2614  		!bytes.Contains(out, []byte("is not supported"))
  2615  	b.flagCache[key] = supported
  2616  	return supported
  2617  }
  2618  
  2619  // gccArchArgs returns arguments to pass to gcc based on the architecture.
  2620  func (b *Builder) gccArchArgs() []string {
  2621  	switch cfg.Goarch {
  2622  	case "386":
  2623  		return []string{"-m32"}
  2624  	case "amd64":
  2625  		if cfg.Goos == "darwin" {
  2626  			return []string{"-arch", "x86_64", "-m64"}
  2627  		}
  2628  		return []string{"-m64"}
  2629  	case "arm64":
  2630  		if cfg.Goos == "darwin" {
  2631  			return []string{"-arch", "arm64"}
  2632  		}
  2633  	case "arm":
  2634  		return []string{"-marm"} // not thumb
  2635  	case "s390x":
  2636  		return []string{"-m64", "-march=z196"}
  2637  	case "mips64", "mips64le":
  2638  		args := []string{"-mabi=64"}
  2639  		if cfg.GOMIPS64 == "hardfloat" {
  2640  			return append(args, "-mhard-float")
  2641  		} else if cfg.GOMIPS64 == "softfloat" {
  2642  			return append(args, "-msoft-float")
  2643  		}
  2644  	case "mips", "mipsle":
  2645  		args := []string{"-mabi=32", "-march=mips32"}
  2646  		if cfg.GOMIPS == "hardfloat" {
  2647  			return append(args, "-mhard-float", "-mfp32", "-mno-odd-spreg")
  2648  		} else if cfg.GOMIPS == "softfloat" {
  2649  			return append(args, "-msoft-float")
  2650  		}
  2651  	case "ppc64":
  2652  		if cfg.Goos == "aix" {
  2653  			return []string{"-maix64"}
  2654  		}
  2655  	}
  2656  	return nil
  2657  }
  2658  
  2659  // envList returns the value of the given environment variable broken
  2660  // into fields, using the default value when the variable is empty.
  2661  func envList(key, def string) []string {
  2662  	v := cfg.Getenv(key)
  2663  	if v == "" {
  2664  		v = def
  2665  	}
  2666  	return strings.Fields(v)
  2667  }
  2668  
  2669  // CFlags returns the flags to use when invoking the C, C++ or Fortran compilers, or cgo.
  2670  func (b *Builder) CFlags(p *load.Package) (cppflags, cflags, cxxflags, fflags, ldflags []string, err error) {
  2671  	defaults := "-g -O2"
  2672  
  2673  	if cppflags, err = buildFlags("CPPFLAGS", "", p.CgoCPPFLAGS, checkCompilerFlags); err != nil {
  2674  		return
  2675  	}
  2676  	if cflags, err = buildFlags("CFLAGS", defaults, p.CgoCFLAGS, checkCompilerFlags); err != nil {
  2677  		return
  2678  	}
  2679  	if cxxflags, err = buildFlags("CXXFLAGS", defaults, p.CgoCXXFLAGS, checkCompilerFlags); err != nil {
  2680  		return
  2681  	}
  2682  	if fflags, err = buildFlags("FFLAGS", defaults, p.CgoFFLAGS, checkCompilerFlags); err != nil {
  2683  		return
  2684  	}
  2685  	if ldflags, err = buildFlags("LDFLAGS", defaults, p.CgoLDFLAGS, checkLinkerFlags); err != nil {
  2686  		return
  2687  	}
  2688  
  2689  	return
  2690  }
  2691  
  2692  func buildFlags(name, defaults string, fromPackage []string, check func(string, string, []string) error) ([]string, error) {
  2693  	if err := check(name, "#cgo "+name, fromPackage); err != nil {
  2694  		return nil, err
  2695  	}
  2696  	return str.StringList(envList("CGO_"+name, defaults), fromPackage), nil
  2697  }
  2698  
  2699  var cgoRe = lazyregexp.New(`[/\\:]`)
  2700  
  2701  func (b *Builder) cgo(a *Action, cgoExe, objdir string, pcCFLAGS, pcLDFLAGS, cgofiles, gccfiles, gxxfiles, mfiles, ffiles []string) (outGo, outObj []string, err error) {
  2702  	p := a.Package
  2703  	cgoCPPFLAGS, cgoCFLAGS, cgoCXXFLAGS, cgoFFLAGS, cgoLDFLAGS, err := b.CFlags(p)
  2704  	if err != nil {
  2705  		return nil, nil, err
  2706  	}
  2707  
  2708  	cgoCPPFLAGS = append(cgoCPPFLAGS, pcCFLAGS...)
  2709  	cgoLDFLAGS = append(cgoLDFLAGS, pcLDFLAGS...)
  2710  	// If we are compiling Objective-C code, then we need to link against libobjc
  2711  	if len(mfiles) > 0 {
  2712  		cgoLDFLAGS = append(cgoLDFLAGS, "-lobjc")
  2713  	}
  2714  
  2715  	// Likewise for Fortran, except there are many Fortran compilers.
  2716  	// Support gfortran out of the box and let others pass the correct link options
  2717  	// via CGO_LDFLAGS
  2718  	if len(ffiles) > 0 {
  2719  		fc := cfg.Getenv("FC")
  2720  		if fc == "" {
  2721  			fc = "gfortran"
  2722  		}
  2723  		if strings.Contains(fc, "gfortran") {
  2724  			cgoLDFLAGS = append(cgoLDFLAGS, "-lgfortran")
  2725  		}
  2726  	}
  2727  
  2728  	if cfg.BuildMSan {
  2729  		cgoCFLAGS = append([]string{"-fsanitize=memory"}, cgoCFLAGS...)
  2730  		cgoLDFLAGS = append([]string{"-fsanitize=memory"}, cgoLDFLAGS...)
  2731  	}
  2732  
  2733  	// Allows including _cgo_export.h, as well as the user's .h files,
  2734  	// from .[ch] files in the package.
  2735  	cgoCPPFLAGS = append(cgoCPPFLAGS, "-I", objdir)
  2736  
  2737  	// cgo
  2738  	// TODO: CGO_FLAGS?
  2739  	gofiles := []string{objdir + "_cgo_gotypes.go"}
  2740  	cfiles := []string{"_cgo_export.c"}
  2741  	for _, fn := range cgofiles {
  2742  		f := strings.TrimSuffix(filepath.Base(fn), ".go")
  2743  		gofiles = append(gofiles, objdir+f+".cgo1.go")
  2744  		cfiles = append(cfiles, f+".cgo2.c")
  2745  	}
  2746  
  2747  	// TODO: make cgo not depend on $GOARCH?
  2748  
  2749  	cgoflags := []string{}
  2750  	if p.Standard && p.ImportPath == "runtime/cgo" {
  2751  		cgoflags = append(cgoflags, "-import_runtime_cgo=false")
  2752  	}
  2753  	if p.Standard && (p.ImportPath == "runtime/race" || p.ImportPath == "runtime/msan" || p.ImportPath == "runtime/cgo") {
  2754  		cgoflags = append(cgoflags, "-import_syscall=false")
  2755  	}
  2756  
  2757  	// Update $CGO_LDFLAGS with p.CgoLDFLAGS.
  2758  	// These flags are recorded in the generated _cgo_gotypes.go file
  2759  	// using //go:cgo_ldflag directives, the compiler records them in the
  2760  	// object file for the package, and then the Go linker passes them
  2761  	// along to the host linker. At this point in the code, cgoLDFLAGS
  2762  	// consists of the original $CGO_LDFLAGS (unchecked) and all the
  2763  	// flags put together from source code (checked).
  2764  	cgoenv := b.cCompilerEnv()
  2765  	if len(cgoLDFLAGS) > 0 {
  2766  		flags := make([]string, len(cgoLDFLAGS))
  2767  		for i, f := range cgoLDFLAGS {
  2768  			flags[i] = strconv.Quote(f)
  2769  		}
  2770  		cgoenv = append(cgoenv, "CGO_LDFLAGS="+strings.Join(flags, " "))
  2771  	}
  2772  
  2773  	if cfg.BuildToolchainName == "gccgo" {
  2774  		if b.gccSupportsFlag([]string{BuildToolchain.compiler()}, "-fsplit-stack") {
  2775  			cgoCFLAGS = append(cgoCFLAGS, "-fsplit-stack")
  2776  		}
  2777  		cgoflags = append(cgoflags, "-gccgo")
  2778  		if pkgpath := gccgoPkgpath(p); pkgpath != "" {
  2779  			cgoflags = append(cgoflags, "-gccgopkgpath="+pkgpath)
  2780  		}
  2781  	}
  2782  
  2783  	switch cfg.BuildBuildmode {
  2784  	case "c-archive", "c-shared":
  2785  		// Tell cgo that if there are any exported functions
  2786  		// it should generate a header file that C code can
  2787  		// #include.
  2788  		cgoflags = append(cgoflags, "-exportheader="+objdir+"_cgo_install.h")
  2789  	}
  2790  
  2791  	execdir := p.Dir
  2792  
  2793  	// Rewrite overlaid paths in cgo files.
  2794  	// cgo adds //line and #line pragmas in generated files with these paths.
  2795  	var trimpath []string
  2796  	for i := range cgofiles {
  2797  		path := mkAbs(p.Dir, cgofiles[i])
  2798  		if opath, ok := fsys.OverlayPath(path); ok {
  2799  			cgofiles[i] = opath
  2800  			trimpath = append(trimpath, opath+"=>"+path)
  2801  		}
  2802  	}
  2803  	if len(trimpath) > 0 {
  2804  		cgoflags = append(cgoflags, "-trimpath", strings.Join(trimpath, ";"))
  2805  	}
  2806  
  2807  	if err := b.run(a, execdir, p.ImportPath, cgoenv, cfg.BuildToolexec, cgoExe, "-objdir", objdir, "-importpath", p.ImportPath, cgoflags, "--", cgoCPPFLAGS, cgoCFLAGS, cgofiles); err != nil {
  2808  		return nil, nil, err
  2809  	}
  2810  	outGo = append(outGo, gofiles...)
  2811  
  2812  	// Use sequential object file names to keep them distinct
  2813  	// and short enough to fit in the .a header file name slots.
  2814  	// We no longer collect them all into _all.o, and we'd like
  2815  	// tools to see both the .o suffix and unique names, so
  2816  	// we need to make them short enough not to be truncated
  2817  	// in the final archive.
  2818  	oseq := 0
  2819  	nextOfile := func() string {
  2820  		oseq++
  2821  		return objdir + fmt.Sprintf("_x%03d.o", oseq)
  2822  	}
  2823  
  2824  	// gcc
  2825  	cflags := str.StringList(cgoCPPFLAGS, cgoCFLAGS)
  2826  	for _, cfile := range cfiles {
  2827  		ofile := nextOfile()
  2828  		if err := b.gcc(a, p, a.Objdir, ofile, cflags, objdir+cfile); err != nil {
  2829  			return nil, nil, err
  2830  		}
  2831  		outObj = append(outObj, ofile)
  2832  	}
  2833  
  2834  	for _, file := range gccfiles {
  2835  		ofile := nextOfile()
  2836  		if err := b.gcc(a, p, a.Objdir, ofile, cflags, file); err != nil {
  2837  			return nil, nil, err
  2838  		}
  2839  		outObj = append(outObj, ofile)
  2840  	}
  2841  
  2842  	cxxflags := str.StringList(cgoCPPFLAGS, cgoCXXFLAGS)
  2843  	for _, file := range gxxfiles {
  2844  		ofile := nextOfile()
  2845  		if err := b.gxx(a, p, a.Objdir, ofile, cxxflags, file); err != nil {
  2846  			return nil, nil, err
  2847  		}
  2848  		outObj = append(outObj, ofile)
  2849  	}
  2850  
  2851  	for _, file := range mfiles {
  2852  		ofile := nextOfile()
  2853  		if err := b.gcc(a, p, a.Objdir, ofile, cflags, file); err != nil {
  2854  			return nil, nil, err
  2855  		}
  2856  		outObj = append(outObj, ofile)
  2857  	}
  2858  
  2859  	fflags := str.StringList(cgoCPPFLAGS, cgoFFLAGS)
  2860  	for _, file := range ffiles {
  2861  		ofile := nextOfile()
  2862  		if err := b.gfortran(a, p, a.Objdir, ofile, fflags, file); err != nil {
  2863  			return nil, nil, err
  2864  		}
  2865  		outObj = append(outObj, ofile)
  2866  	}
  2867  
  2868  	switch cfg.BuildToolchainName {
  2869  	case "gc":
  2870  		importGo := objdir + "_cgo_import.go"
  2871  		if err := b.dynimport(a, p, objdir, importGo, cgoExe, cflags, cgoLDFLAGS, outObj); err != nil {
  2872  			return nil, nil, err
  2873  		}
  2874  		outGo = append(outGo, importGo)
  2875  
  2876  	case "gccgo":
  2877  		defunC := objdir + "_cgo_defun.c"
  2878  		defunObj := objdir + "_cgo_defun.o"
  2879  		if err := BuildToolchain.cc(b, a, defunObj, defunC); err != nil {
  2880  			return nil, nil, err
  2881  		}
  2882  		outObj = append(outObj, defunObj)
  2883  
  2884  	default:
  2885  		noCompiler()
  2886  	}
  2887  
  2888  	// Double check the //go:cgo_ldflag comments in the generated files.
  2889  	// The compiler only permits such comments in files whose base name
  2890  	// starts with "_cgo_". Make sure that the comments in those files
  2891  	// are safe. This is a backstop against people somehow smuggling
  2892  	// such a comment into a file generated by cgo.
  2893  	if cfg.BuildToolchainName == "gc" && !cfg.BuildN {
  2894  		var flags []string
  2895  		for _, f := range outGo {
  2896  			if !strings.HasPrefix(filepath.Base(f), "_cgo_") {
  2897  				continue
  2898  			}
  2899  
  2900  			src, err := os.ReadFile(f)
  2901  			if err != nil {
  2902  				return nil, nil, err
  2903  			}
  2904  
  2905  			const cgoLdflag = "//go:cgo_ldflag"
  2906  			idx := bytes.Index(src, []byte(cgoLdflag))
  2907  			for idx >= 0 {
  2908  				// We are looking at //go:cgo_ldflag.
  2909  				// Find start of line.
  2910  				start := bytes.LastIndex(src[:idx], []byte("\n"))
  2911  				if start == -1 {
  2912  					start = 0
  2913  				}
  2914  
  2915  				// Find end of line.
  2916  				end := bytes.Index(src[idx:], []byte("\n"))
  2917  				if end == -1 {
  2918  					end = len(src)
  2919  				} else {
  2920  					end += idx
  2921  				}
  2922  
  2923  				// Check for first line comment in line.
  2924  				// We don't worry about /* */ comments,
  2925  				// which normally won't appear in files
  2926  				// generated by cgo.
  2927  				commentStart := bytes.Index(src[start:], []byte("//"))
  2928  				commentStart += start
  2929  				// If that line comment is //go:cgo_ldflag,
  2930  				// it's a match.
  2931  				if bytes.HasPrefix(src[commentStart:], []byte(cgoLdflag)) {
  2932  					// Pull out the flag, and unquote it.
  2933  					// This is what the compiler does.
  2934  					flag := string(src[idx+len(cgoLdflag) : end])
  2935  					flag = strings.TrimSpace(flag)
  2936  					flag = strings.Trim(flag, `"`)
  2937  					flags = append(flags, flag)
  2938  				}
  2939  				src = src[end:]
  2940  				idx = bytes.Index(src, []byte(cgoLdflag))
  2941  			}
  2942  		}
  2943  
  2944  		// We expect to find the contents of cgoLDFLAGS in flags.
  2945  		if len(cgoLDFLAGS) > 0 {
  2946  		outer:
  2947  			for i := range flags {
  2948  				for j, f := range cgoLDFLAGS {
  2949  					if f != flags[i+j] {
  2950  						continue outer
  2951  					}
  2952  				}
  2953  				flags = append(flags[:i], flags[i+len(cgoLDFLAGS):]...)
  2954  				break
  2955  			}
  2956  		}
  2957  
  2958  		if err := checkLinkerFlags("LDFLAGS", "go:cgo_ldflag", flags); err != nil {
  2959  			return nil, nil, err
  2960  		}
  2961  	}
  2962  
  2963  	return outGo, outObj, nil
  2964  }
  2965  
  2966  // dynimport creates a Go source file named importGo containing
  2967  // //go:cgo_import_dynamic directives for each symbol or library
  2968  // dynamically imported by the object files outObj.
  2969  func (b *Builder) dynimport(a *Action, p *load.Package, objdir, importGo, cgoExe string, cflags, cgoLDFLAGS, outObj []string) error {
  2970  	cfile := objdir + "_cgo_main.c"
  2971  	ofile := objdir + "_cgo_main.o"
  2972  	if err := b.gcc(a, p, objdir, ofile, cflags, cfile); err != nil {
  2973  		return err
  2974  	}
  2975  
  2976  	linkobj := str.StringList(ofile, outObj, mkAbsFiles(p.Dir, p.SysoFiles))
  2977  	dynobj := objdir + "_cgo_.o"
  2978  
  2979  	// we need to use -pie for Linux/ARM to get accurate imported sym
  2980  	ldflags := cgoLDFLAGS
  2981  	if (cfg.Goarch == "arm" && cfg.Goos == "linux") || cfg.Goos == "android" {
  2982  		// -static -pie doesn't make sense, and causes link errors.
  2983  		// Issue 26197.
  2984  		n := make([]string, 0, len(ldflags))
  2985  		for _, flag := range ldflags {
  2986  			if flag != "-static" {
  2987  				n = append(n, flag)
  2988  			}
  2989  		}
  2990  		ldflags = append(n, "-pie")
  2991  	}
  2992  	if err := b.gccld(a, p, objdir, dynobj, ldflags, linkobj); err != nil {
  2993  		return err
  2994  	}
  2995  
  2996  	// cgo -dynimport
  2997  	var cgoflags []string
  2998  	if p.Standard && p.ImportPath == "runtime/cgo" {
  2999  		cgoflags = []string{"-dynlinker"} // record path to dynamic linker
  3000  	}
  3001  	return b.run(a, base.Cwd(), p.ImportPath, b.cCompilerEnv(), cfg.BuildToolexec, cgoExe, "-dynpackage", p.Name, "-dynimport", dynobj, "-dynout", importGo, cgoflags)
  3002  }
  3003  
  3004  // Run SWIG on all SWIG input files.
  3005  // TODO: Don't build a shared library, once SWIG emits the necessary
  3006  // pragmas for external linking.
  3007  func (b *Builder) swig(a *Action, p *load.Package, objdir string, pcCFLAGS []string) (outGo, outC, outCXX []string, err error) {
  3008  	if err := b.swigVersionCheck(); err != nil {
  3009  		return nil, nil, nil, err
  3010  	}
  3011  
  3012  	intgosize, err := b.swigIntSize(objdir)
  3013  	if err != nil {
  3014  		return nil, nil, nil, err
  3015  	}
  3016  
  3017  	for _, f := range p.SwigFiles {
  3018  		goFile, cFile, err := b.swigOne(a, p, f, objdir, pcCFLAGS, false, intgosize)
  3019  		if err != nil {
  3020  			return nil, nil, nil, err
  3021  		}
  3022  		if goFile != "" {
  3023  			outGo = append(outGo, goFile)
  3024  		}
  3025  		if cFile != "" {
  3026  			outC = append(outC, cFile)
  3027  		}
  3028  	}
  3029  	for _, f := range p.SwigCXXFiles {
  3030  		goFile, cxxFile, err := b.swigOne(a, p, f, objdir, pcCFLAGS, true, intgosize)
  3031  		if err != nil {
  3032  			return nil, nil, nil, err
  3033  		}
  3034  		if goFile != "" {
  3035  			outGo = append(outGo, goFile)
  3036  		}
  3037  		if cxxFile != "" {
  3038  			outCXX = append(outCXX, cxxFile)
  3039  		}
  3040  	}
  3041  	return outGo, outC, outCXX, nil
  3042  }
  3043  
  3044  // Make sure SWIG is new enough.
  3045  var (
  3046  	swigCheckOnce sync.Once
  3047  	swigCheck     error
  3048  )
  3049  
  3050  func (b *Builder) swigDoVersionCheck() error {
  3051  	out, err := b.runOut(nil, "", nil, "swig", "-version")
  3052  	if err != nil {
  3053  		return err
  3054  	}
  3055  	re := regexp.MustCompile(`[vV]ersion +([\d]+)([.][\d]+)?([.][\d]+)?`)
  3056  	matches := re.FindSubmatch(out)
  3057  	if matches == nil {
  3058  		// Can't find version number; hope for the best.
  3059  		return nil
  3060  	}
  3061  
  3062  	major, err := strconv.Atoi(string(matches[1]))
  3063  	if err != nil {
  3064  		// Can't find version number; hope for the best.
  3065  		return nil
  3066  	}
  3067  	const errmsg = "must have SWIG version >= 3.0.6"
  3068  	if major < 3 {
  3069  		return errors.New(errmsg)
  3070  	}
  3071  	if major > 3 {
  3072  		// 4.0 or later
  3073  		return nil
  3074  	}
  3075  
  3076  	// We have SWIG version 3.x.
  3077  	if len(matches[2]) > 0 {
  3078  		minor, err := strconv.Atoi(string(matches[2][1:]))
  3079  		if err != nil {
  3080  			return nil
  3081  		}
  3082  		if minor > 0 {
  3083  			// 3.1 or later
  3084  			return nil
  3085  		}
  3086  	}
  3087  
  3088  	// We have SWIG version 3.0.x.
  3089  	if len(matches[3]) > 0 {
  3090  		patch, err := strconv.Atoi(string(matches[3][1:]))
  3091  		if err != nil {
  3092  			return nil
  3093  		}
  3094  		if patch < 6 {
  3095  			// Before 3.0.6.
  3096  			return errors.New(errmsg)
  3097  		}
  3098  	}
  3099  
  3100  	return nil
  3101  }
  3102  
  3103  func (b *Builder) swigVersionCheck() error {
  3104  	swigCheckOnce.Do(func() {
  3105  		swigCheck = b.swigDoVersionCheck()
  3106  	})
  3107  	return swigCheck
  3108  }
  3109  
  3110  // Find the value to pass for the -intgosize option to swig.
  3111  var (
  3112  	swigIntSizeOnce  sync.Once
  3113  	swigIntSize      string
  3114  	swigIntSizeError error
  3115  )
  3116  
  3117  // This code fails to build if sizeof(int) <= 32
  3118  const swigIntSizeCode = `
  3119  package main
  3120  const i int = 1 << 32
  3121  `
  3122  
  3123  // Determine the size of int on the target system for the -intgosize option
  3124  // of swig >= 2.0.9. Run only once.
  3125  func (b *Builder) swigDoIntSize(objdir string) (intsize string, err error) {
  3126  	if cfg.BuildN {
  3127  		return "$INTBITS", nil
  3128  	}
  3129  	src := filepath.Join(b.WorkDir, "swig_intsize.go")
  3130  	if err = os.WriteFile(src, []byte(swigIntSizeCode), 0666); err != nil {
  3131  		return
  3132  	}
  3133  	srcs := []string{src}
  3134  
  3135  	p := load.GoFilesPackage(context.TODO(), load.PackageOpts{}, srcs)
  3136  
  3137  	if _, _, e := BuildToolchain.gc(b, &Action{Mode: "swigDoIntSize", Package: p, Objdir: objdir}, "", nil, nil, "", false, srcs); e != nil {
  3138  		return "32", nil
  3139  	}
  3140  	return "64", nil
  3141  }
  3142  
  3143  // Determine the size of int on the target system for the -intgosize option
  3144  // of swig >= 2.0.9.
  3145  func (b *Builder) swigIntSize(objdir string) (intsize string, err error) {
  3146  	swigIntSizeOnce.Do(func() {
  3147  		swigIntSize, swigIntSizeError = b.swigDoIntSize(objdir)
  3148  	})
  3149  	return swigIntSize, swigIntSizeError
  3150  }
  3151  
  3152  // Run SWIG on one SWIG input file.
  3153  func (b *Builder) swigOne(a *Action, p *load.Package, file, objdir string, pcCFLAGS []string, cxx bool, intgosize string) (outGo, outC string, err error) {
  3154  	cgoCPPFLAGS, cgoCFLAGS, cgoCXXFLAGS, _, _, err := b.CFlags(p)
  3155  	if err != nil {
  3156  		return "", "", err
  3157  	}
  3158  
  3159  	var cflags []string
  3160  	if cxx {
  3161  		cflags = str.StringList(cgoCPPFLAGS, pcCFLAGS, cgoCXXFLAGS)
  3162  	} else {
  3163  		cflags = str.StringList(cgoCPPFLAGS, pcCFLAGS, cgoCFLAGS)
  3164  	}
  3165  
  3166  	n := 5 // length of ".swig"
  3167  	if cxx {
  3168  		n = 8 // length of ".swigcxx"
  3169  	}
  3170  	base := file[:len(file)-n]
  3171  	goFile := base + ".go"
  3172  	gccBase := base + "_wrap."
  3173  	gccExt := "c"
  3174  	if cxx {
  3175  		gccExt = "cxx"
  3176  	}
  3177  
  3178  	gccgo := cfg.BuildToolchainName == "gccgo"
  3179  
  3180  	// swig
  3181  	args := []string{
  3182  		"-go",
  3183  		"-cgo",
  3184  		"-intgosize", intgosize,
  3185  		"-module", base,
  3186  		"-o", objdir + gccBase + gccExt,
  3187  		"-outdir", objdir,
  3188  	}
  3189  
  3190  	for _, f := range cflags {
  3191  		if len(f) > 3 && f[:2] == "-I" {
  3192  			args = append(args, f)
  3193  		}
  3194  	}
  3195  
  3196  	if gccgo {
  3197  		args = append(args, "-gccgo")
  3198  		if pkgpath := gccgoPkgpath(p); pkgpath != "" {
  3199  			args = append(args, "-go-pkgpath", pkgpath)
  3200  		}
  3201  	}
  3202  	if cxx {
  3203  		args = append(args, "-c++")
  3204  	}
  3205  
  3206  	out, err := b.runOut(a, p.Dir, nil, "swig", args, file)
  3207  	if err != nil {
  3208  		if len(out) > 0 {
  3209  			if bytes.Contains(out, []byte("-intgosize")) || bytes.Contains(out, []byte("-cgo")) {
  3210  				return "", "", errors.New("must have SWIG version >= 3.0.6")
  3211  			}
  3212  			b.showOutput(a, p.Dir, p.Desc(), b.processOutput(out)) // swig error
  3213  			return "", "", errPrintedOutput
  3214  		}
  3215  		return "", "", err
  3216  	}
  3217  	if len(out) > 0 {
  3218  		b.showOutput(a, p.Dir, p.Desc(), b.processOutput(out)) // swig warning
  3219  	}
  3220  
  3221  	// If the input was x.swig, the output is x.go in the objdir.
  3222  	// But there might be an x.go in the original dir too, and if it
  3223  	// uses cgo as well, cgo will be processing both and will
  3224  	// translate both into x.cgo1.go in the objdir, overwriting one.
  3225  	// Rename x.go to _x_swig.go to avoid this problem.
  3226  	// We ignore files in the original dir that begin with underscore
  3227  	// so _x_swig.go cannot conflict with an original file we were
  3228  	// going to compile.
  3229  	goFile = objdir + goFile
  3230  	newGoFile := objdir + "_" + base + "_swig.go"
  3231  	if err := os.Rename(goFile, newGoFile); err != nil {
  3232  		return "", "", err
  3233  	}
  3234  	return newGoFile, objdir + gccBase + gccExt, nil
  3235  }
  3236  
  3237  // disableBuildID adjusts a linker command line to avoid creating a
  3238  // build ID when creating an object file rather than an executable or
  3239  // shared library. Some systems, such as Ubuntu, always add
  3240  // --build-id to every link, but we don't want a build ID when we are
  3241  // producing an object file. On some of those system a plain -r (not
  3242  // -Wl,-r) will turn off --build-id, but clang 3.0 doesn't support a
  3243  // plain -r. I don't know how to turn off --build-id when using clang
  3244  // other than passing a trailing --build-id=none. So that is what we
  3245  // do, but only on systems likely to support it, which is to say,
  3246  // systems that normally use gold or the GNU linker.
  3247  func (b *Builder) disableBuildID(ldflags []string) []string {
  3248  	switch cfg.Goos {
  3249  	case "android", "dragonfly", "linux", "netbsd":
  3250  		ldflags = append(ldflags, "-Wl,--build-id=none")
  3251  	}
  3252  	return ldflags
  3253  }
  3254  
  3255  // mkAbsFiles converts files into a list of absolute files,
  3256  // assuming they were originally relative to dir,
  3257  // and returns that new list.
  3258  func mkAbsFiles(dir string, files []string) []string {
  3259  	abs := make([]string, len(files))
  3260  	for i, f := range files {
  3261  		if !filepath.IsAbs(f) {
  3262  			f = filepath.Join(dir, f)
  3263  		}
  3264  		abs[i] = f
  3265  	}
  3266  	return abs
  3267  }
  3268  
  3269  // passLongArgsInResponseFiles modifies cmd such that, for
  3270  // certain programs, long arguments are passed in "response files", a
  3271  // file on disk with the arguments, with one arg per line. An actual
  3272  // argument starting with '@' means that the rest of the argument is
  3273  // a filename of arguments to expand.
  3274  //
  3275  // See issues 18468 (Windows) and 37768 (Darwin).
  3276  func passLongArgsInResponseFiles(cmd *exec.Cmd) (cleanup func()) {
  3277  	cleanup = func() {} // no cleanup by default
  3278  
  3279  	var argLen int
  3280  	for _, arg := range cmd.Args {
  3281  		argLen += len(arg)
  3282  	}
  3283  
  3284  	// If we're not approaching 32KB of args, just pass args normally.
  3285  	// (use 30KB instead to be conservative; not sure how accounting is done)
  3286  	if !useResponseFile(cmd.Path, argLen) {
  3287  		return
  3288  	}
  3289  
  3290  	tf, err := os.CreateTemp("", "args")
  3291  	if err != nil {
  3292  		log.Fatalf("error writing long arguments to response file: %v", err)
  3293  	}
  3294  	cleanup = func() { os.Remove(tf.Name()) }
  3295  	var buf bytes.Buffer
  3296  	for _, arg := range cmd.Args[1:] {
  3297  		fmt.Fprintf(&buf, "%s\n", encodeArg(arg))
  3298  	}
  3299  	if _, err := tf.Write(buf.Bytes()); err != nil {
  3300  		tf.Close()
  3301  		cleanup()
  3302  		log.Fatalf("error writing long arguments to response file: %v", err)
  3303  	}
  3304  	if err := tf.Close(); err != nil {
  3305  		cleanup()
  3306  		log.Fatalf("error writing long arguments to response file: %v", err)
  3307  	}
  3308  	cmd.Args = []string{cmd.Args[0], "@" + tf.Name()}
  3309  	return cleanup
  3310  }
  3311  
  3312  // Windows has a limit of 32 KB arguments. To be conservative and not worry
  3313  // about whether that includes spaces or not, just use 30 KB. Darwin's limit is
  3314  // less clear. The OS claims 256KB, but we've seen failures with arglen as
  3315  // small as 50KB.
  3316  const ArgLengthForResponseFile = (30 << 10)
  3317  
  3318  func useResponseFile(path string, argLen int) bool {
  3319  	// Unless the program uses objabi.Flagparse, which understands
  3320  	// response files, don't use response files.
  3321  	// TODO: do we need more commands? asm? cgo? For now, no.
  3322  	prog := strings.TrimSuffix(filepath.Base(path), ".exe")
  3323  	switch prog {
  3324  	case "compile", "link":
  3325  	default:
  3326  		return false
  3327  	}
  3328  
  3329  	if argLen > ArgLengthForResponseFile {
  3330  		return true
  3331  	}
  3332  
  3333  	// On the Go build system, use response files about 10% of the
  3334  	// time, just to exercise this codepath.
  3335  	isBuilder := os.Getenv("GO_BUILDER_NAME") != ""
  3336  	if isBuilder && rand.Intn(10) == 0 {
  3337  		return true
  3338  	}
  3339  
  3340  	return false
  3341  }
  3342  
  3343  // encodeArg encodes an argument for response file writing.
  3344  func encodeArg(arg string) string {
  3345  	// If there aren't any characters we need to reencode, fastpath out.
  3346  	if !strings.ContainsAny(arg, "\\\n") {
  3347  		return arg
  3348  	}
  3349  	var b strings.Builder
  3350  	for _, r := range arg {
  3351  		switch r {
  3352  		case '\\':
  3353  			b.WriteByte('\\')
  3354  			b.WriteByte('\\')
  3355  		case '\n':
  3356  			b.WriteByte('\\')
  3357  			b.WriteByte('n')
  3358  		default:
  3359  			b.WriteRune(r)
  3360  		}
  3361  	}
  3362  	return b.String()
  3363  }
  3364  

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