github.com/bir3/gocompiler@v0.9.2202/src/cmd/cgo/main.go (about)

     1  // Copyright 2009 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  // Cgo; see doc.go for an overview.
     6  
     7  // TODO(rsc):
     8  //	Emit correct line number annotations.
     9  //	Make gc understand the annotations.
    10  
    11  package cgo
    12  
    13  import (
    14  	"github.com/bir3/gocompiler/src/cmd/cgo/flag"
    15  	"github.com/bir3/gocompiler/src/cmd/cgo/flag_objabi"
    16  	"fmt"
    17  	"github.com/bir3/gocompiler/src/go/ast"
    18  	"github.com/bir3/gocompiler/src/go/printer"
    19  	"github.com/bir3/gocompiler/src/go/token"
    20  	"github.com/bir3/gocompiler/src/internal/buildcfg"
    21  	"io"
    22  	"os"
    23  	"path/filepath"
    24  	"reflect"
    25  	"runtime"
    26  	"sort"
    27  	"strings"
    28  
    29  	"github.com/bir3/gocompiler/src/cmd/internal/edit"
    30  	"github.com/bir3/gocompiler/src/cmd/internal/notsha256"
    31  	"github.com/bir3/gocompiler/src/cmd/internal/objabi"
    32  )
    33  
    34  // A Package collects information about the package we're going to write.
    35  type Package struct {
    36  	PackageName	string	// name of package
    37  	PackagePath	string
    38  	PtrSize		int64
    39  	IntSize		int64
    40  	GccOptions	[]string
    41  	GccIsClang	bool
    42  	LdFlags		[]string	// #cgo LDFLAGS
    43  	Written		map[string]bool
    44  	Name		map[string]*Name	// accumulated Name from Files
    45  	ExpFunc		[]*ExpFunc		// accumulated ExpFunc from Files
    46  	Decl		[]ast.Decl
    47  	GoFiles		[]string	// list of Go files
    48  	GccFiles	[]string	// list of gcc output files
    49  	Preamble	string		// collected preamble for _cgo_export.h
    50  	typedefs	map[string]bool	// type names that appear in the types of the objects we're interested in
    51  	typedefList	[]typedefInfo
    52  	noCallbacks	map[string]bool	// C function names with #cgo nocallback directive
    53  	noEscapes	map[string]bool	// C function names with #cgo noescape directive
    54  }
    55  
    56  // A typedefInfo is an element on Package.typedefList: a typedef name
    57  // and the position where it was required.
    58  type typedefInfo struct {
    59  	typedef	string
    60  	pos	token.Pos
    61  }
    62  
    63  // A File collects information about a single Go input file.
    64  type File struct {
    65  	AST		*ast.File		// parsed AST
    66  	Comments	[]*ast.CommentGroup	// comments from file
    67  	Package		string			// Package name
    68  	Preamble	string			// C preamble (doc comment on import "C")
    69  	Ref		[]*Ref			// all references to C.xxx in AST
    70  	Calls		[]*Call			// all calls to C.xxx in AST
    71  	ExpFunc		[]*ExpFunc		// exported functions for this file
    72  	Name		map[string]*Name	// map from Go name to Name
    73  	NamePos		map[*Name]token.Pos	// map from Name to position of the first reference
    74  	NoCallbacks	map[string]bool		// C function names that with #cgo nocallback directive
    75  	NoEscapes	map[string]bool		// C function names that with #cgo noescape directive
    76  	Edit		*edit.Buffer
    77  }
    78  
    79  func (f *File) offset(p token.Pos) int {
    80  	return fset.Position(p).Offset
    81  }
    82  
    83  func nameKeys(m map[string]*Name) []string {
    84  	var ks []string
    85  	for k := range m {
    86  		ks = append(ks, k)
    87  	}
    88  	sort.Strings(ks)
    89  	return ks
    90  }
    91  
    92  // A Call refers to a call of a C.xxx function in the AST.
    93  type Call struct {
    94  	Call		*ast.CallExpr
    95  	Deferred	bool
    96  	Done		bool
    97  }
    98  
    99  // A Ref refers to an expression of the form C.xxx in the AST.
   100  type Ref struct {
   101  	Name	*Name
   102  	Expr	*ast.Expr
   103  	Context	astContext
   104  	Done	bool
   105  }
   106  
   107  func (r *Ref) Pos() token.Pos {
   108  	return (*r.Expr).Pos()
   109  }
   110  
   111  var nameKinds = []string{"iconst", "fconst", "sconst", "type", "var", "fpvar", "func", "macro", "not-type"}
   112  
   113  // A Name collects information about C.xxx.
   114  type Name struct {
   115  	Go		string	// name used in Go referring to package C
   116  	Mangle		string	// name used in generated Go
   117  	C		string	// name used in C
   118  	Define		string	// #define expansion
   119  	Kind		string	// one of the nameKinds
   120  	Type		*Type	// the type of xxx
   121  	FuncType	*FuncType
   122  	AddError	bool
   123  	Const		string	// constant definition
   124  }
   125  
   126  // IsVar reports whether Kind is either "var" or "fpvar"
   127  func (n *Name) IsVar() bool {
   128  	return n.Kind == "var" || n.Kind == "fpvar"
   129  }
   130  
   131  // IsConst reports whether Kind is either "iconst", "fconst" or "sconst"
   132  func (n *Name) IsConst() bool {
   133  	return strings.HasSuffix(n.Kind, "const")
   134  }
   135  
   136  // An ExpFunc is an exported function, callable from C.
   137  // Such functions are identified in the Go input file
   138  // by doc comments containing the line //export ExpName
   139  type ExpFunc struct {
   140  	Func	*ast.FuncDecl
   141  	ExpName	string	// name to use from C
   142  	Doc	string
   143  }
   144  
   145  // A TypeRepr contains the string representation of a type.
   146  type TypeRepr struct {
   147  	Repr		string
   148  	FormatArgs	[]interface{}
   149  }
   150  
   151  // A Type collects information about a type in both the C and Go worlds.
   152  type Type struct {
   153  	Size		int64
   154  	Align		int64
   155  	C		*TypeRepr
   156  	Go		ast.Expr
   157  	EnumValues	map[string]int64
   158  	Typedef		string
   159  	BadPointer	bool	// this pointer type should be represented as a uintptr (deprecated)
   160  }
   161  
   162  // A FuncType collects information about a function type in both the C and Go worlds.
   163  type FuncType struct {
   164  	Params	[]*Type
   165  	Result	*Type
   166  	Go	*ast.FuncType
   167  }
   168  
   169  func usage() {
   170  	fmt.Fprint(os.Stderr, "usage: cgo -- [compiler options] file.go ...\n")
   171  	flag.PrintDefaults()
   172  	os.Exit(2)
   173  }
   174  
   175  var ptrSizeMap = map[string]int64{
   176  	"386":		4,
   177  	"alpha":	8,
   178  	"amd64":	8,
   179  	"arm":		4,
   180  	"arm64":	8,
   181  	"loong64":	8,
   182  	"m68k":		4,
   183  	"mips":		4,
   184  	"mipsle":	4,
   185  	"mips64":	8,
   186  	"mips64le":	8,
   187  	"nios2":	4,
   188  	"ppc":		4,
   189  	"ppc64":	8,
   190  	"ppc64le":	8,
   191  	"riscv":	4,
   192  	"riscv64":	8,
   193  	"s390":		4,
   194  	"s390x":	8,
   195  	"sh":		4,
   196  	"shbe":		4,
   197  	"sparc":	4,
   198  	"sparc64":	8,
   199  }
   200  
   201  var intSizeMap = map[string]int64{
   202  	"386":		4,
   203  	"alpha":	8,
   204  	"amd64":	8,
   205  	"arm":		4,
   206  	"arm64":	8,
   207  	"loong64":	8,
   208  	"m68k":		4,
   209  	"mips":		4,
   210  	"mipsle":	4,
   211  	"mips64":	8,
   212  	"mips64le":	8,
   213  	"nios2":	4,
   214  	"ppc":		4,
   215  	"ppc64":	8,
   216  	"ppc64le":	8,
   217  	"riscv":	4,
   218  	"riscv64":	8,
   219  	"s390":		4,
   220  	"s390x":	8,
   221  	"sh":		4,
   222  	"shbe":		4,
   223  	"sparc":	4,
   224  	"sparc64":	8,
   225  }
   226  
   227  var cPrefix string
   228  
   229  var fset = token.NewFileSet()
   230  
   231  var dynobj = flag.String("dynimport", "", "if non-empty, print dynamic import data for that file")
   232  var dynout = flag.String("dynout", "", "write -dynimport output to this file")
   233  var dynpackage = flag.String("dynpackage", "main", "set Go package for -dynimport output")
   234  var dynlinker = flag.Bool("dynlinker", false, "record dynamic linker information in -dynimport mode")
   235  
   236  // This flag is for bootstrapping a new Go implementation,
   237  // to generate Go types that match the data layout and
   238  // constant values used in the host's C libraries and system calls.
   239  var godefs = flag.Bool("godefs", false, "for bootstrap: write Go definitions for C file to standard output")
   240  
   241  var srcDir = flag.String("srcdir", "", "source directory")
   242  var objDir = flag.String("objdir", "", "object directory")
   243  var importPath = flag.String("importpath", "", "import path of package being built (for comments in generated files)")
   244  var exportHeader = flag.String("exportheader", "", "where to write export header if any exported functions")
   245  
   246  var gccgo = flag.Bool("gccgo", false, "generate files for use with gccgo")
   247  var gccgoprefix = flag.String("gccgoprefix", "", "-fgo-prefix option used with gccgo")
   248  var gccgopkgpath = flag.String("gccgopkgpath", "", "-fgo-pkgpath option used with gccgo")
   249  var gccgoMangler func(string) string
   250  var gccgoDefineCgoIncomplete = flag.Bool("gccgo_define_cgoincomplete", false, "define cgo.Incomplete for older gccgo/GoLLVM")
   251  var importRuntimeCgo = flag.Bool("import_runtime_cgo", true, "import runtime/cgo in generated code")
   252  var importSyscall = flag.Bool("import_syscall", true, "import syscall in generated code")
   253  var trimpath = flag.String("trimpath", "", "applies supplied rewrites or trims prefixes to recorded source file paths")
   254  
   255  var goarch, goos, gomips, gomips64 string
   256  var gccBaseCmd []string
   257  
   258  func Main() {
   259  	flag_objabi.AddVersionFlag()	// -V
   260  	flag_objabi.Flagparse(usage)
   261  
   262  	if *gccgoDefineCgoIncomplete {
   263  		if !*gccgo {
   264  			fmt.Fprintf(os.Stderr, "cgo: -gccgo_define_cgoincomplete without -gccgo\n")
   265  			os.Exit(2)
   266  		}
   267  		incomplete = "_cgopackage_Incomplete"
   268  	}
   269  
   270  	if *dynobj != "" {
   271  		// cgo -dynimport is essentially a separate helper command
   272  		// built into the cgo binary. It scans a gcc-produced executable
   273  		// and dumps information about the imported symbols and the
   274  		// imported libraries. The 'go build' rules for cgo prepare an
   275  		// appropriate executable and then use its import information
   276  		// instead of needing to make the linkers duplicate all the
   277  		// specialized knowledge gcc has about where to look for imported
   278  		// symbols and which ones to use.
   279  		dynimport(*dynobj)
   280  		return
   281  	}
   282  
   283  	if *godefs {
   284  		// Generating definitions pulled from header files,
   285  		// to be checked into Go repositories.
   286  		// Line numbers are just noise.
   287  		conf.Mode &^= printer.SourcePos
   288  	}
   289  
   290  	args := flag.Args()
   291  	if len(args) < 1 {
   292  		usage()
   293  	}
   294  
   295  	// Find first arg that looks like a go file and assume everything before
   296  	// that are options to pass to gcc.
   297  	var i int
   298  	for i = len(args); i > 0; i-- {
   299  		if !strings.HasSuffix(args[i-1], ".go") {
   300  			break
   301  		}
   302  	}
   303  	if i == len(args) {
   304  		usage()
   305  	}
   306  
   307  	// Save original command line arguments for the godefs generated comment. Relative file
   308  	// paths in os.Args will be rewritten to absolute file paths in the loop below.
   309  	osArgs := make([]string, len(os.Args))
   310  	copy(osArgs, os.Args[:])
   311  	goFiles := args[i:]
   312  
   313  	for _, arg := range args[:i] {
   314  		if arg == "-fsanitize=thread" {
   315  			tsanProlog = yesTsanProlog
   316  		}
   317  		if arg == "-fsanitize=memory" {
   318  			msanProlog = yesMsanProlog
   319  		}
   320  	}
   321  
   322  	p := newPackage(args[:i])
   323  
   324  	// We need a C compiler to be available. Check this.
   325  	var err error
   326  	gccBaseCmd, err = checkGCCBaseCmd()
   327  	if err != nil {
   328  		fatalf("%v", err)
   329  		os.Exit(2)
   330  	}
   331  
   332  	// Record CGO_LDFLAGS from the environment for external linking.
   333  	if ldflags := os.Getenv("CGO_LDFLAGS"); ldflags != "" {
   334  		args, err := splitQuoted(ldflags)
   335  		if err != nil {
   336  			fatalf("bad CGO_LDFLAGS: %q (%s)", ldflags, err)
   337  		}
   338  		p.addToFlag("LDFLAGS", args)
   339  	}
   340  
   341  	// Need a unique prefix for the global C symbols that
   342  	// we use to coordinate between gcc and ourselves.
   343  	// We already put _cgo_ at the beginning, so the main
   344  	// concern is other cgo wrappers for the same functions.
   345  	// Use the beginning of the notsha256 of the input to disambiguate.
   346  	h := notsha256.New()
   347  	io.WriteString(h, *importPath)
   348  	fs := make([]*File, len(goFiles))
   349  	for i, input := range goFiles {
   350  		if *srcDir != "" {
   351  			input = filepath.Join(*srcDir, input)
   352  		}
   353  
   354  		// Create absolute path for file, so that it will be used in error
   355  		// messages and recorded in debug line number information.
   356  		// This matches the rest of the toolchain. See golang.org/issue/5122.
   357  		if aname, err := filepath.Abs(input); err == nil {
   358  			input = aname
   359  		}
   360  
   361  		b, err := os.ReadFile(input)
   362  		if err != nil {
   363  			fatalf("%s", err)
   364  		}
   365  		if _, err = h.Write(b); err != nil {
   366  			fatalf("%s", err)
   367  		}
   368  
   369  		// Apply trimpath to the file path. The path won't be read from after this point.
   370  		input, _ = objabi.ApplyRewrites(input, *trimpath)
   371  		if strings.ContainsAny(input, "\r\n") {
   372  			// ParseGo, (*Package).writeOutput, and printer.Fprint in SourcePos mode
   373  			// all emit line directives, which don't permit newlines in the file path.
   374  			// Bail early if we see anything newline-like in the trimmed path.
   375  			fatalf("input path contains newline character: %q", input)
   376  		}
   377  		goFiles[i] = input
   378  
   379  		f := new(File)
   380  		f.Edit = edit.NewBuffer(b)
   381  		f.ParseGo(input, b)
   382  		f.ProcessCgoDirectives()
   383  		fs[i] = f
   384  	}
   385  
   386  	cPrefix = fmt.Sprintf("_%x", h.Sum(nil)[0:6])
   387  
   388  	if *objDir == "" {
   389  		// make sure that _obj directory exists, so that we can write
   390  		// all the output files there.
   391  		os.Mkdir("_obj", 0777)
   392  		*objDir = "_obj"
   393  	}
   394  	*objDir += string(filepath.Separator)
   395  
   396  	for i, input := range goFiles {
   397  		f := fs[i]
   398  		p.Translate(f)
   399  		for _, cref := range f.Ref {
   400  			switch cref.Context {
   401  			case ctxCall, ctxCall2:
   402  				if cref.Name.Kind != "type" {
   403  					break
   404  				}
   405  				old := *cref.Expr
   406  				*cref.Expr = cref.Name.Type.Go
   407  				f.Edit.Replace(f.offset(old.Pos()), f.offset(old.End()), gofmt(cref.Name.Type.Go))
   408  			}
   409  		}
   410  		if nerrors > 0 {
   411  			os.Exit(2)
   412  		}
   413  		p.PackagePath = f.Package
   414  		p.Record(f)
   415  		if *godefs {
   416  			os.Stdout.WriteString(p.godefs(f, osArgs))
   417  		} else {
   418  			p.writeOutput(f, input)
   419  		}
   420  	}
   421  	cFunctions := make(map[string]bool)
   422  	for _, key := range nameKeys(p.Name) {
   423  		n := p.Name[key]
   424  		if n.FuncType != nil {
   425  			cFunctions[n.C] = true
   426  		}
   427  	}
   428  
   429  	for funcName := range p.noEscapes {
   430  		if _, found := cFunctions[funcName]; !found {
   431  			error_(token.NoPos, "#cgo noescape %s: no matched C function", funcName)
   432  		}
   433  	}
   434  
   435  	for funcName := range p.noCallbacks {
   436  		if _, found := cFunctions[funcName]; !found {
   437  			error_(token.NoPos, "#cgo nocallback %s: no matched C function", funcName)
   438  		}
   439  	}
   440  
   441  	if !*godefs {
   442  		p.writeDefs()
   443  	}
   444  	if nerrors > 0 {
   445  		os.Exit(2)
   446  	}
   447  }
   448  
   449  // newPackage returns a new Package that will invoke
   450  // gcc with the additional arguments specified in args.
   451  func newPackage(args []string) *Package {
   452  	goarch = runtime.GOARCH
   453  	if s := os.Getenv("GOARCH"); s != "" {
   454  		goarch = s
   455  	}
   456  	goos = runtime.GOOS
   457  	if s := os.Getenv("GOOS"); s != "" {
   458  		goos = s
   459  	}
   460  	buildcfg.Check()
   461  	gomips = buildcfg.GOMIPS
   462  	gomips64 = buildcfg.GOMIPS64
   463  	ptrSize := ptrSizeMap[goarch]
   464  	if ptrSize == 0 {
   465  		fatalf("unknown ptrSize for $GOARCH %q", goarch)
   466  	}
   467  	intSize := intSizeMap[goarch]
   468  	if intSize == 0 {
   469  		fatalf("unknown intSize for $GOARCH %q", goarch)
   470  	}
   471  
   472  	// Reset locale variables so gcc emits English errors [sic].
   473  	os.Setenv("LANG", "en_US.UTF-8")
   474  	os.Setenv("LC_ALL", "C")
   475  
   476  	p := &Package{
   477  		PtrSize:	ptrSize,
   478  		IntSize:	intSize,
   479  		Written:	make(map[string]bool),
   480  		noCallbacks:	make(map[string]bool),
   481  		noEscapes:	make(map[string]bool),
   482  	}
   483  	p.addToFlag("CFLAGS", args)
   484  	return p
   485  }
   486  
   487  // Record what needs to be recorded about f.
   488  func (p *Package) Record(f *File) {
   489  	if p.PackageName == "" {
   490  		p.PackageName = f.Package
   491  	} else if p.PackageName != f.Package {
   492  		error_(token.NoPos, "inconsistent package names: %s, %s", p.PackageName, f.Package)
   493  	}
   494  
   495  	if p.Name == nil {
   496  		p.Name = f.Name
   497  	} else {
   498  		for k, v := range f.Name {
   499  			if p.Name[k] == nil {
   500  				p.Name[k] = v
   501  			} else if p.incompleteTypedef(p.Name[k].Type) {
   502  				p.Name[k] = v
   503  			} else if p.incompleteTypedef(v.Type) {
   504  				// Nothing to do.
   505  			} else if _, ok := nameToC[k]; ok {
   506  				// Names we predefine may appear inconsistent
   507  				// if some files typedef them and some don't.
   508  				// Issue 26743.
   509  			} else if !reflect.DeepEqual(p.Name[k], v) {
   510  				error_(token.NoPos, "inconsistent definitions for C.%s", fixGo(k))
   511  			}
   512  		}
   513  	}
   514  
   515  	// merge nocallback & noescape
   516  	for k, v := range f.NoCallbacks {
   517  		p.noCallbacks[k] = v
   518  	}
   519  	for k, v := range f.NoEscapes {
   520  		p.noEscapes[k] = v
   521  	}
   522  
   523  	if f.ExpFunc != nil {
   524  		p.ExpFunc = append(p.ExpFunc, f.ExpFunc...)
   525  		p.Preamble += "\n" + f.Preamble
   526  	}
   527  	p.Decl = append(p.Decl, f.AST.Decls...)
   528  }
   529  
   530  // incompleteTypedef reports whether t appears to be an incomplete
   531  // typedef definition.
   532  func (p *Package) incompleteTypedef(t *Type) bool {
   533  	return t == nil || (t.Size == 0 && t.Align == -1)
   534  }