gccgo.go

     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  package work
     6  
     7  import (
     8  	"bytes"
     9  	"fmt"
    10  	"os"
    11  	"os/exec"
    12  	"path/filepath"
    13  	"strings"
    14  	"sync"
    15  
    16  	"cmd/go/internal/base"
    17  	"cmd/go/internal/cfg"
    18  	"cmd/go/internal/fsys"
    19  	"cmd/go/internal/load"
    20  	"cmd/go/internal/str"
    21  	"cmd/internal/pathcache"
    22  	"cmd/internal/pkgpath"
    23  )
    24  
    25  // The Gccgo toolchain.
    26  
    27  type gccgoToolchain struct{}
    28  
    29  var GccgoName, GccgoBin string
    30  var gccgoErr error
    31  
    32  func init() {
    33  	GccgoName = cfg.Getenv("GCCGO")
    34  	if GccgoName == "" {
    35  		GccgoName = "gccgo"
    36  	}
    37  	GccgoBin, gccgoErr = pathcache.LookPath(GccgoName)
    38  }
    39  
    40  func (gccgoToolchain) compiler() string {
    41  	checkGccgoBin()
    42  	return GccgoBin
    43  }
    44  
    45  func (gccgoToolchain) linker() string {
    46  	checkGccgoBin()
    47  	return GccgoBin
    48  }
    49  
    50  func (gccgoToolchain) ar() []string {
    51  	return envList("AR", "ar")
    52  }
    53  
    54  func checkGccgoBin() {
    55  	if gccgoErr == nil {
    56  		return
    57  	}
    58  	fmt.Fprintf(os.Stderr, "cmd/go: gccgo: %s\n", gccgoErr)
    59  	base.SetExitStatus(2)
    60  	base.Exit()
    61  }
    62  
    63  func (tools gccgoToolchain) gc(b *Builder, a *Action, archive string, importcfg, embedcfg []byte, symabis string, asmhdr bool, pgoProfile string, gofiles []string) (ofile string, output []byte, err error) {
    64  	p := a.Package
    65  	sh := b.Shell(a)
    66  	objdir := a.Objdir
    67  	out := "_go_.o"
    68  	ofile = objdir + out
    69  	gcargs := []string{"-g"}
    70  	gcargs = append(gcargs, b.gccArchArgs()...)
    71  	gcargs = append(gcargs, "-fdebug-prefix-map="+b.WorkDir+"=/tmp/go-build")
    72  	gcargs = append(gcargs, "-gno-record-gcc-switches")
    73  	if pkgpath := gccgoPkgpath(p); pkgpath != "" {
    74  		gcargs = append(gcargs, "-fgo-pkgpath="+pkgpath)
    75  	}
    76  	if p.Internal.LocalPrefix != "" {
    77  		gcargs = append(gcargs, "-fgo-relative-import-path="+p.Internal.LocalPrefix)
    78  	}
    79  
    80  	args := str.StringList(tools.compiler(), "-c", gcargs, "-o", ofile, forcedGccgoflags)
    81  	if importcfg != nil {
    82  		if b.gccSupportsFlag(args[:1], "-fgo-importcfg=/dev/null") {
    83  			if err := sh.writeFile(objdir+"importcfg", importcfg); err != nil {
    84  				return "", nil, err
    85  			}
    86  			args = append(args, "-fgo-importcfg="+objdir+"importcfg")
    87  		} else {
    88  			root := objdir + "_importcfgroot_"
    89  			if err := buildImportcfgSymlinks(sh, root, importcfg); err != nil {
    90  				return "", nil, err
    91  			}
    92  			args = append(args, "-I", root)
    93  		}
    94  	}
    95  	if embedcfg != nil && b.gccSupportsFlag(args[:1], "-fgo-embedcfg=/dev/null") {
    96  		if err := sh.writeFile(objdir+"embedcfg", embedcfg); err != nil {
    97  			return "", nil, err
    98  		}
    99  		args = append(args, "-fgo-embedcfg="+objdir+"embedcfg")
   100  	}
   101  
   102  	if b.gccSupportsFlag(args[:1], "-ffile-prefix-map=a=b") {
   103  		if cfg.BuildTrimpath {
   104  			args = append(args, "-ffile-prefix-map="+base.Cwd()+"=.")
   105  			args = append(args, "-ffile-prefix-map="+b.WorkDir+"=/tmp/go-build")
   106  		}
   107  		if fsys.OverlayFile != "" {
   108  			for _, name := range gofiles {
   109  				absPath := mkAbs(p.Dir, name)
   110  				if !fsys.Replaced(absPath) {
   111  					continue
   112  				}
   113  				toPath := absPath
   114  				// gccgo only applies the last matching rule, so also handle the case where
   115  				// BuildTrimpath is true and the path is relative to base.Cwd().
   116  				if cfg.BuildTrimpath && str.HasFilePathPrefix(toPath, base.Cwd()) {
   117  					toPath = "." + toPath[len(base.Cwd()):]
   118  				}
   119  				args = append(args, "-ffile-prefix-map="+fsys.Actual(absPath)+"="+toPath)
   120  			}
   121  		}
   122  	}
   123  
   124  	args = append(args, a.Package.Internal.Gccgoflags...)
   125  	for _, f := range gofiles {
   126  		f := mkAbs(p.Dir, f)
   127  		// Overlay files if necessary.
   128  		// See comment on gctoolchain.gc about overlay TODOs
   129  		args = append(args, fsys.Actual(f))
   130  	}
   131  
   132  	output, err = sh.runOut(p.Dir, nil, args)
   133  	return ofile, output, err
   134  }
   135  
   136  // buildImportcfgSymlinks builds in root a tree of symlinks
   137  // implementing the directives from importcfg.
   138  // This serves as a temporary transition mechanism until
   139  // we can depend on gccgo reading an importcfg directly.
   140  // (The Go 1.9 and later gc compilers already do.)
   141  func buildImportcfgSymlinks(sh *Shell, root string, importcfg []byte) error {
   142  	for lineNum, line := range strings.Split(string(importcfg), "\n") {
   143  		lineNum++ // 1-based
   144  		line = strings.TrimSpace(line)
   145  		if line == "" {
   146  			continue
   147  		}
   148  		if line == "" || strings.HasPrefix(line, "#") {
   149  			continue
   150  		}
   151  		var verb, args string
   152  		if i := strings.Index(line, " "); i < 0 {
   153  			verb = line
   154  		} else {
   155  			verb, args = line[:i], strings.TrimSpace(line[i+1:])
   156  		}
   157  		before, after, _ := strings.Cut(args, "=")
   158  		switch verb {
   159  		default:
   160  			base.Fatalf("importcfg:%d: unknown directive %q", lineNum, verb)
   161  		case "packagefile":
   162  			if before == "" || after == "" {
   163  				return fmt.Errorf(`importcfg:%d: invalid packagefile: syntax is "packagefile path=filename": %s`, lineNum, line)
   164  			}
   165  			archive := gccgoArchive(root, before)
   166  			if err := sh.Mkdir(filepath.Dir(archive)); err != nil {
   167  				return err
   168  			}
   169  			if err := sh.Symlink(after, archive); err != nil {
   170  				return err
   171  			}
   172  		case "importmap":
   173  			if before == "" || after == "" {
   174  				return fmt.Errorf(`importcfg:%d: invalid importmap: syntax is "importmap old=new": %s`, lineNum, line)
   175  			}
   176  			beforeA := gccgoArchive(root, before)
   177  			afterA := gccgoArchive(root, after)
   178  			if err := sh.Mkdir(filepath.Dir(beforeA)); err != nil {
   179  				return err
   180  			}
   181  			if err := sh.Mkdir(filepath.Dir(afterA)); err != nil {
   182  				return err
   183  			}
   184  			if err := sh.Symlink(afterA, beforeA); err != nil {
   185  				return err
   186  			}
   187  		case "packageshlib":
   188  			return fmt.Errorf("gccgo -importcfg does not support shared libraries")
   189  		}
   190  	}
   191  	return nil
   192  }
   193  
   194  func (tools gccgoToolchain) asm(b *Builder, a *Action, sfiles []string) ([]string, error) {
   195  	p := a.Package
   196  	var ofiles []string
   197  	for _, sfile := range sfiles {
   198  		base := filepath.Base(sfile)
   199  		ofile := a.Objdir + base[:len(base)-len(".s")] + ".o"
   200  		ofiles = append(ofiles, ofile)
   201  		sfile = fsys.Actual(mkAbs(p.Dir, sfile))
   202  		defs := []string{"-D", "GOOS_" + cfg.Goos, "-D", "GOARCH_" + cfg.Goarch}
   203  		if pkgpath := tools.gccgoCleanPkgpath(b, p); pkgpath != "" {
   204  			defs = append(defs, `-D`, `GOPKGPATH=`+pkgpath)
   205  		}
   206  		defs = tools.maybePIC(defs)
   207  		defs = append(defs, b.gccArchArgs()...)
   208  		err := b.Shell(a).run(p.Dir, p.ImportPath, nil, tools.compiler(), "-xassembler-with-cpp", "-I", a.Objdir, "-c", "-o", ofile, defs, sfile)
   209  		if err != nil {
   210  			return nil, err
   211  		}
   212  	}
   213  	return ofiles, nil
   214  }
   215  
   216  func (gccgoToolchain) symabis(b *Builder, a *Action, sfiles []string) (string, error) {
   217  	return "", nil
   218  }
   219  
   220  func gccgoArchive(basedir, imp string) string {
   221  	end := filepath.FromSlash(imp + ".a")
   222  	afile := filepath.Join(basedir, end)
   223  	// add "lib" to the final element
   224  	return filepath.Join(filepath.Dir(afile), "lib"+filepath.Base(afile))
   225  }
   226  
   227  func (tools gccgoToolchain) pack(b *Builder, a *Action, afile string, ofiles []string) error {
   228  	p := a.Package
   229  	sh := b.Shell(a)
   230  	objdir := a.Objdir
   231  	absOfiles := make([]string, 0, len(ofiles))
   232  	for _, f := range ofiles {
   233  		absOfiles = append(absOfiles, mkAbs(objdir, f))
   234  	}
   235  	var arArgs []string
   236  	if cfg.Goos == "aix" && cfg.Goarch == "ppc64" {
   237  		// AIX puts both 32-bit and 64-bit objects in the same archive.
   238  		// Tell the AIX "ar" command to only care about 64-bit objects.
   239  		arArgs = []string{"-X64"}
   240  	}
   241  	absAfile := mkAbs(objdir, afile)
   242  	// Try with D modifier first, then without if that fails.
   243  	output, err := sh.runOut(p.Dir, nil, tools.ar(), arArgs, "rcD", absAfile, absOfiles)
   244  	if err != nil {
   245  		return sh.run(p.Dir, p.ImportPath, nil, tools.ar(), arArgs, "rc", absAfile, absOfiles)
   246  	}
   247  
   248  	// Show the output if there is any even without errors.
   249  	return sh.reportCmd("", "", output, nil)
   250  }
   251  
   252  func (tools gccgoToolchain) link(b *Builder, root *Action, out, importcfg string, allactions []*Action, buildmode, desc string) error {
   253  	sh := b.Shell(root)
   254  
   255  	// gccgo needs explicit linking with all package dependencies,
   256  	// and all LDFLAGS from cgo dependencies.
   257  	afiles := []string{}
   258  	shlibs := []string{}
   259  	ldflags := b.gccArchArgs()
   260  	cgoldflags := []string{}
   261  	usesCgo := false
   262  	cxx := false
   263  	objc := false
   264  	fortran := false
   265  	if root.Package != nil {
   266  		cxx = len(root.Package.CXXFiles) > 0 || len(root.Package.SwigCXXFiles) > 0
   267  		objc = len(root.Package.MFiles) > 0
   268  		fortran = len(root.Package.FFiles) > 0
   269  	}
   270  
   271  	readCgoFlags := func(flagsFile string) error {
   272  		flags, err := os.ReadFile(flagsFile)
   273  		if err != nil {
   274  			return err
   275  		}
   276  		const ldflagsPrefix = "_CGO_LDFLAGS="
   277  		for _, line := range strings.Split(string(flags), "\n") {
   278  			if strings.HasPrefix(line, ldflagsPrefix) {
   279  				flag := line[len(ldflagsPrefix):]
   280  				// Every _cgo_flags file has -g and -O2 in _CGO_LDFLAGS
   281  				// but they don't mean anything to the linker so filter
   282  				// them out.
   283  				if flag != "-g" && !strings.HasPrefix(flag, "-O") {
   284  					cgoldflags = append(cgoldflags, flag)
   285  				}
   286  			}
   287  		}
   288  		return nil
   289  	}
   290  
   291  	var arArgs []string
   292  	if cfg.Goos == "aix" && cfg.Goarch == "ppc64" {
   293  		// AIX puts both 32-bit and 64-bit objects in the same archive.
   294  		// Tell the AIX "ar" command to only care about 64-bit objects.
   295  		arArgs = []string{"-X64"}
   296  	}
   297  
   298  	newID := 0
   299  	readAndRemoveCgoFlags := func(archive string) (string, error) {
   300  		newID++
   301  		newArchive := root.Objdir + fmt.Sprintf("_pkg%d_.a", newID)
   302  		if err := sh.CopyFile(newArchive, archive, 0666, false); err != nil {
   303  			return "", err
   304  		}
   305  		if cfg.BuildN || cfg.BuildX {
   306  			sh.ShowCmd("", "ar d %s _cgo_flags", newArchive)
   307  			if cfg.BuildN {
   308  				// TODO(rsc): We could do better about showing the right _cgo_flags even in -n mode.
   309  				// Either the archive is already built and we can read them out,
   310  				// or we're printing commands to build the archive and can
   311  				// forward the _cgo_flags directly to this step.
   312  				return "", nil
   313  			}
   314  		}
   315  		err := sh.run(root.Objdir, desc, nil, tools.ar(), arArgs, "x", newArchive, "_cgo_flags")
   316  		if err != nil {
   317  			return "", err
   318  		}
   319  		err = sh.run(".", desc, nil, tools.ar(), arArgs, "d", newArchive, "_cgo_flags")
   320  		if err != nil {
   321  			return "", err
   322  		}
   323  		err = readCgoFlags(filepath.Join(root.Objdir, "_cgo_flags"))
   324  		if err != nil {
   325  			return "", err
   326  		}
   327  		return newArchive, nil
   328  	}
   329  
   330  	// If using -linkshared, find the shared library deps.
   331  	haveShlib := make(map[string]bool)
   332  	targetBase := filepath.Base(root.Target)
   333  	if cfg.BuildLinkshared {
   334  		for _, a := range root.Deps {
   335  			p := a.Package
   336  			if p == nil || p.Shlib == "" {
   337  				continue
   338  			}
   339  
   340  			// The .a we are linking into this .so
   341  			// will have its Shlib set to this .so.
   342  			// Don't start thinking we want to link
   343  			// this .so into itself.
   344  			base := filepath.Base(p.Shlib)
   345  			if base != targetBase {
   346  				haveShlib[base] = true
   347  			}
   348  		}
   349  	}
   350  
   351  	// Arrange the deps into afiles and shlibs.
   352  	addedShlib := make(map[string]bool)
   353  	for _, a := range root.Deps {
   354  		p := a.Package
   355  		if p != nil && p.Shlib != "" && haveShlib[filepath.Base(p.Shlib)] {
   356  			// This is a package linked into a shared
   357  			// library that we will put into shlibs.
   358  			continue
   359  		}
   360  
   361  		if haveShlib[filepath.Base(a.Target)] {
   362  			// This is a shared library we want to link against.
   363  			if !addedShlib[a.Target] {
   364  				shlibs = append(shlibs, a.Target)
   365  				addedShlib[a.Target] = true
   366  			}
   367  			continue
   368  		}
   369  
   370  		if p != nil {
   371  			target := a.built
   372  			if p.UsesCgo() || p.UsesSwig() {
   373  				var err error
   374  				target, err = readAndRemoveCgoFlags(target)
   375  				if err != nil {
   376  					continue
   377  				}
   378  			}
   379  
   380  			afiles = append(afiles, target)
   381  		}
   382  	}
   383  
   384  	for _, a := range allactions {
   385  		if a.Package == nil {
   386  			continue
   387  		}
   388  		if len(a.Package.CgoFiles) > 0 {
   389  			usesCgo = true
   390  		}
   391  		if a.Package.UsesSwig() {
   392  			usesCgo = true
   393  		}
   394  		if len(a.Package.CXXFiles) > 0 || len(a.Package.SwigCXXFiles) > 0 {
   395  			cxx = true
   396  		}
   397  		if len(a.Package.MFiles) > 0 {
   398  			objc = true
   399  		}
   400  		if len(a.Package.FFiles) > 0 {
   401  			fortran = true
   402  		}
   403  	}
   404  
   405  	wholeArchive := []string{"-Wl,--whole-archive"}
   406  	noWholeArchive := []string{"-Wl,--no-whole-archive"}
   407  	if cfg.Goos == "aix" {
   408  		wholeArchive = nil
   409  		noWholeArchive = nil
   410  	}
   411  	ldflags = append(ldflags, wholeArchive...)
   412  	ldflags = append(ldflags, afiles...)
   413  	ldflags = append(ldflags, noWholeArchive...)
   414  
   415  	ldflags = append(ldflags, cgoldflags...)
   416  	ldflags = append(ldflags, envList("CGO_LDFLAGS", "")...)
   417  	if cfg.Goos != "aix" {
   418  		ldflags = str.StringList("-Wl,-(", ldflags, "-Wl,-)")
   419  	}
   420  
   421  	if root.buildID != "" {
   422  		// On systems that normally use gold or the GNU linker,
   423  		// use the --build-id option to write a GNU build ID note.
   424  		switch cfg.Goos {
   425  		case "android", "dragonfly", "linux", "netbsd":
   426  			ldflags = append(ldflags, fmt.Sprintf("-Wl,--build-id=0x%x", root.buildID))
   427  		}
   428  	}
   429  
   430  	var rLibPath string
   431  	if cfg.Goos == "aix" {
   432  		rLibPath = "-Wl,-blibpath="
   433  	} else {
   434  		rLibPath = "-Wl,-rpath="
   435  	}
   436  	for _, shlib := range shlibs {
   437  		ldflags = append(
   438  			ldflags,
   439  			"-L"+filepath.Dir(shlib),
   440  			rLibPath+filepath.Dir(shlib),
   441  			"-l"+strings.TrimSuffix(
   442  				strings.TrimPrefix(filepath.Base(shlib), "lib"),
   443  				".so"))
   444  	}
   445  
   446  	var realOut string
   447  	goLibBegin := str.StringList(wholeArchive, "-lgolibbegin", noWholeArchive)
   448  	switch buildmode {
   449  	case "exe":
   450  		if usesCgo && cfg.Goos == "linux" {
   451  			ldflags = append(ldflags, "-Wl,-E")
   452  		}
   453  
   454  	case "c-archive":
   455  		// Link the Go files into a single .o, and also link
   456  		// in -lgolibbegin.
   457  		//
   458  		// We need to use --whole-archive with -lgolibbegin
   459  		// because it doesn't define any symbols that will
   460  		// cause the contents to be pulled in; it's just
   461  		// initialization code.
   462  		//
   463  		// The user remains responsible for linking against
   464  		// -lgo -lpthread -lm in the final link. We can't use
   465  		// -r to pick them up because we can't combine
   466  		// split-stack and non-split-stack code in a single -r
   467  		// link, and libgo picks up non-split-stack code from
   468  		// libffi.
   469  		ldflags = append(ldflags, "-Wl,-r", "-nostdlib")
   470  		ldflags = append(ldflags, goLibBegin...)
   471  
   472  		if nopie := b.gccNoPie([]string{tools.linker()}); nopie != "" {
   473  			ldflags = append(ldflags, nopie)
   474  		}
   475  
   476  		// We are creating an object file, so we don't want a build ID.
   477  		if root.buildID == "" {
   478  			ldflags = b.disableBuildID(ldflags)
   479  		}
   480  
   481  		realOut = out
   482  		out = out + ".o"
   483  
   484  	case "c-shared":
   485  		ldflags = append(ldflags, "-shared", "-nostdlib")
   486  		if cfg.Goos != "windows" {
   487  			ldflags = append(ldflags, "-Wl,-z,nodelete")
   488  		}
   489  		ldflags = append(ldflags, goLibBegin...)
   490  		ldflags = append(ldflags, "-lgo", "-lgcc_s", "-lgcc", "-lc", "-lgcc")
   491  
   492  	case "shared":
   493  		if cfg.Goos != "aix" {
   494  			ldflags = append(ldflags, "-zdefs")
   495  		}
   496  		ldflags = append(ldflags, "-shared", "-nostdlib", "-lgo", "-lgcc_s", "-lgcc", "-lc")
   497  
   498  	default:
   499  		base.Fatalf("-buildmode=%s not supported for gccgo", buildmode)
   500  	}
   501  
   502  	switch buildmode {
   503  	case "exe", "c-shared":
   504  		if cxx {
   505  			ldflags = append(ldflags, "-lstdc++")
   506  		}
   507  		if objc {
   508  			ldflags = append(ldflags, "-lobjc")
   509  		}
   510  		if fortran {
   511  			fc := cfg.Getenv("FC")
   512  			if fc == "" {
   513  				fc = "gfortran"
   514  			}
   515  			// support gfortran out of the box and let others pass the correct link options
   516  			// via CGO_LDFLAGS
   517  			if strings.Contains(fc, "gfortran") {
   518  				ldflags = append(ldflags, "-lgfortran")
   519  			}
   520  		}
   521  	}
   522  
   523  	if err := sh.run(".", desc, nil, tools.linker(), "-o", out, ldflags, forcedGccgoflags, root.Package.Internal.Gccgoflags); err != nil {
   524  		return err
   525  	}
   526  
   527  	switch buildmode {
   528  	case "c-archive":
   529  		if err := sh.run(".", desc, nil, tools.ar(), arArgs, "rc", realOut, out); err != nil {
   530  			return err
   531  		}
   532  	}
   533  	return nil
   534  }
   535  
   536  func (tools gccgoToolchain) ld(b *Builder, root *Action, targetPath, importcfg, mainpkg string) error {
   537  	return tools.link(b, root, targetPath, importcfg, root.Deps, ldBuildmode, root.Package.ImportPath)
   538  }
   539  
   540  func (tools gccgoToolchain) ldShared(b *Builder, root *Action, toplevelactions []*Action, targetPath, importcfg string, allactions []*Action) error {
   541  	return tools.link(b, root, targetPath, importcfg, allactions, "shared", targetPath)
   542  }
   543  
   544  func (tools gccgoToolchain) cc(b *Builder, a *Action, ofile, cfile string) error {
   545  	p := a.Package
   546  	inc := filepath.Join(cfg.GOROOT, "pkg", "include")
   547  	cfile = mkAbs(p.Dir, cfile)
   548  	defs := []string{"-D", "GOOS_" + cfg.Goos, "-D", "GOARCH_" + cfg.Goarch}
   549  	defs = append(defs, b.gccArchArgs()...)
   550  	if pkgpath := tools.gccgoCleanPkgpath(b, p); pkgpath != "" {
   551  		defs = append(defs, `-D`, `GOPKGPATH="`+pkgpath+`"`)
   552  	}
   553  	compiler := envList("CC", cfg.DefaultCC(cfg.Goos, cfg.Goarch))
   554  	if b.gccSupportsFlag(compiler, "-fsplit-stack") {
   555  		defs = append(defs, "-fsplit-stack")
   556  	}
   557  	defs = tools.maybePIC(defs)
   558  	if b.gccSupportsFlag(compiler, "-ffile-prefix-map=a=b") {
   559  		defs = append(defs, "-ffile-prefix-map="+base.Cwd()+"=.")
   560  		defs = append(defs, "-ffile-prefix-map="+b.WorkDir+"=/tmp/go-build")
   561  	} else if b.gccSupportsFlag(compiler, "-fdebug-prefix-map=a=b") {
   562  		defs = append(defs, "-fdebug-prefix-map="+b.WorkDir+"=/tmp/go-build")
   563  	}
   564  	if b.gccSupportsFlag(compiler, "-gno-record-gcc-switches") {
   565  		defs = append(defs, "-gno-record-gcc-switches")
   566  	}
   567  	return b.Shell(a).run(p.Dir, p.ImportPath, nil, compiler, "-Wall", "-g",
   568  		"-I", a.Objdir, "-I", inc, "-o", ofile, defs, "-c", cfile)
   569  }
   570  
   571  // maybePIC adds -fPIC to the list of arguments if needed.
   572  func (tools gccgoToolchain) maybePIC(args []string) []string {
   573  	switch cfg.BuildBuildmode {
   574  	case "c-shared", "shared", "plugin":
   575  		args = append(args, "-fPIC")
   576  	}
   577  	return args
   578  }
   579  
   580  func gccgoPkgpath(p *load.Package) string {
   581  	if p.Internal.Build.IsCommand() && !p.Internal.ForceLibrary {
   582  		return ""
   583  	}
   584  	return p.ImportPath
   585  }
   586  
   587  var gccgoToSymbolFuncOnce sync.Once
   588  var gccgoToSymbolFunc func(string) string
   589  
   590  func (tools gccgoToolchain) gccgoCleanPkgpath(b *Builder, p *load.Package) string {
   591  	gccgoToSymbolFuncOnce.Do(func() {
   592  		tmpdir := b.WorkDir
   593  		if cfg.BuildN {
   594  			tmpdir = os.TempDir()
   595  		}
   596  		fn, err := pkgpath.ToSymbolFunc(tools.compiler(), tmpdir)
   597  		if err != nil {
   598  			fmt.Fprintf(os.Stderr, "cmd/go: %v\n", err)
   599  			base.SetExitStatus(2)
   600  			base.Exit()
   601  		}
   602  		gccgoToSymbolFunc = fn
   603  	})
   604  
   605  	return gccgoToSymbolFunc(gccgoPkgpath(p))
   606  }
   607  
   608  var (
   609  	gccgoSupportsCgoIncompleteOnce sync.Once
   610  	gccgoSupportsCgoIncomplete     bool
   611  )
   612  
   613  const gccgoSupportsCgoIncompleteCode = `
   614  package p
   615  
   616  import "runtime/cgo"
   617  
   618  type I cgo.Incomplete
   619  `
   620  
   621  // supportsCgoIncomplete reports whether the gccgo/GoLLVM compiler
   622  // being used supports cgo.Incomplete, which was added in GCC 13.
   623  //
   624  // This takes an Action only for output reporting purposes.
   625  // The result value is unrelated to the Action.
   626  func (tools gccgoToolchain) supportsCgoIncomplete(b *Builder, a *Action) bool {
   627  	gccgoSupportsCgoIncompleteOnce.Do(func() {
   628  		sh := b.Shell(a)
   629  
   630  		fail := func(err error) {
   631  			fmt.Fprintf(os.Stderr, "cmd/go: %v\n", err)
   632  			base.SetExitStatus(2)
   633  			base.Exit()
   634  		}
   635  
   636  		tmpdir := b.WorkDir
   637  		if cfg.BuildN {
   638  			tmpdir = os.TempDir()
   639  		}
   640  		f, err := os.CreateTemp(tmpdir, "*_gccgo_cgoincomplete.go")
   641  		if err != nil {
   642  			fail(err)
   643  		}
   644  		fn := f.Name()
   645  		f.Close()
   646  		defer os.Remove(fn)
   647  
   648  		if err := os.WriteFile(fn, []byte(gccgoSupportsCgoIncompleteCode), 0644); err != nil {
   649  			fail(err)
   650  		}
   651  
   652  		on := strings.TrimSuffix(fn, ".go") + ".o"
   653  		if cfg.BuildN || cfg.BuildX {
   654  			sh.ShowCmd(tmpdir, "%s -c -o %s %s || true", tools.compiler(), on, fn)
   655  			// Since this function affects later builds,
   656  			// and only generates temporary files,
   657  			// we run the command even with -n.
   658  		}
   659  		cmd := exec.Command(tools.compiler(), "-c", "-o", on, fn)
   660  		cmd.Dir = tmpdir
   661  		var buf bytes.Buffer
   662  		cmd.Stdout = &buf
   663  		cmd.Stderr = &buf
   664  		err = cmd.Run()
   665  		gccgoSupportsCgoIncomplete = err == nil
   666  		if cfg.BuildN || cfg.BuildX {
   667  			// Show output. We always pass a nil err because errors are an
   668  			// expected outcome in this case.
   669  			desc := sh.fmtCmd(tmpdir, "%s -c -o %s %s", tools.compiler(), on, fn)
   670  			sh.reportCmd(desc, tmpdir, buf.Bytes(), nil)
   671  		}
   672  	})
   673  	return gccgoSupportsCgoIncomplete
   674  }
   675
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