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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Cgo; see gmp.go for an overview.
// TODO(rsc):
// Emit correct line number annotations.
// Make gc understand the annotations.
package main
import (
"crypto/md5"
"flag"
"fmt"
"go/ast"
"go/printer"
"go/token"
"io"
"os"
"path/filepath"
"reflect"
"runtime"
"sort"
"strings"
)
// A Package collects information about the package we're going to write.
type Package struct {
PackageName string // name of package
PackagePath string
PtrSize int64
IntSize int64
GccOptions []string
GccIsClang bool
CgoFlags map[string][]string // #cgo flags (CFLAGS, LDFLAGS)
Written map[string]bool
Name map[string]*Name // accumulated Name from Files
ExpFunc []*ExpFunc // accumulated ExpFunc from Files
Decl []ast.Decl
GoFiles []string // list of Go files
GccFiles []string // list of gcc output files
Preamble string // collected preamble for _cgo_export.h
}
// A File collects information about a single Go input file.
type File struct {
AST *ast.File // parsed AST
Comments []*ast.CommentGroup // comments from file
Package string // Package name
Preamble string // C preamble (doc comment on import "C")
Ref []*Ref // all references to C.xxx in AST
ExpFunc []*ExpFunc // exported functions for this file
Name map[string]*Name // map from Go name to Name
}
func nameKeys(m map[string]*Name) []string {
var ks []string
for k := range m {
ks = append(ks, k)
}
sort.Strings(ks)
return ks
}
// A Ref refers to an expression of the form C.xxx in the AST.
type Ref struct {
Name *Name
Expr *ast.Expr
Context string // "type", "expr", "call", or "call2"
}
func (r *Ref) Pos() token.Pos {
return (*r.Expr).Pos()
}
// A Name collects information about C.xxx.
type Name struct {
Go string // name used in Go referring to package C
Mangle string // name used in generated Go
C string // name used in C
Define string // #define expansion
Kind string // "const", "type", "var", "fpvar", "func", "not-type"
Type *Type // the type of xxx
FuncType *FuncType
AddError bool
Const string // constant definition
}
// IsVar reports whether Kind is either "var" or "fpvar"
func (n *Name) IsVar() bool {
return n.Kind == "var" || n.Kind == "fpvar"
}
// A ExpFunc is an exported function, callable from C.
// Such functions are identified in the Go input file
// by doc comments containing the line //export ExpName
type ExpFunc struct {
Func *ast.FuncDecl
ExpName string // name to use from C
Doc string
}
// A TypeRepr contains the string representation of a type.
type TypeRepr struct {
Repr string
FormatArgs []interface{}
}
// A Type collects information about a type in both the C and Go worlds.
type Type struct {
Size int64
Align int64
C *TypeRepr
Go ast.Expr
EnumValues map[string]int64
Typedef string
}
// A FuncType collects information about a function type in both the C and Go worlds.
type FuncType struct {
Params []*Type
Result *Type
Go *ast.FuncType
}
func usage() {
fmt.Fprint(os.Stderr, "usage: cgo -- [compiler options] file.go ...\n")
flag.PrintDefaults()
os.Exit(2)
}
var ptrSizeMap = map[string]int64{
"386": 4,
"alpha": 8,
"amd64": 8,
"arm": 4,
"arm64": 8,
"m68k": 4,
"mipso32": 4,
"mipsn32": 4,
"mipso64": 8,
"mipsn64": 8,
"ppc": 4,
"ppc64": 8,
"ppc64le": 8,
"s390": 4,
"s390x": 8,
"sparc": 4,
"sparc64": 8,
}
var intSizeMap = map[string]int64{
"386": 4,
"alpha": 8,
"amd64": 8,
"arm": 4,
"arm64": 8,
"m68k": 4,
"mipso32": 4,
"mipsn32": 4,
"mipso64": 8,
"mipsn64": 8,
"ppc": 4,
"ppc64": 8,
"ppc64le": 8,
"s390": 4,
"s390x": 8,
"sparc": 4,
"sparc64": 8,
}
var cPrefix string
var fset = token.NewFileSet()
var dynobj = flag.String("dynimport", "", "if non-empty, print dynamic import data for that file")
var dynout = flag.String("dynout", "", "write -dynimport output to this file")
var dynpackage = flag.String("dynpackage", "main", "set Go package for -dynimport output")
var dynlinker = flag.Bool("dynlinker", false, "record dynamic linker information in -dynimport mode")
// This flag is for bootstrapping a new Go implementation,
// to generate Go types that match the data layout and
// constant values used in the host's C libraries and system calls.
var godefs = flag.Bool("godefs", false, "for bootstrap: write Go definitions for C file to standard output")
var objDir = flag.String("objdir", "", "object directory")
var importPath = flag.String("importpath", "", "import path of package being built (for comments in generated files)")
var exportHeader = flag.String("exportheader", "", "where to write export header if any exported functions")
var gccgo = flag.Bool("gccgo", false, "generate files for use with gccgo")
var gccgoprefix = flag.String("gccgoprefix", "", "-fgo-prefix option used with gccgo")
var gccgopkgpath = flag.String("gccgopkgpath", "", "-fgo-pkgpath option used with gccgo")
var importRuntimeCgo = flag.Bool("import_runtime_cgo", true, "import runtime/cgo in generated code")
var importSyscall = flag.Bool("import_syscall", true, "import syscall in generated code")
var goarch, goos string
func main() {
flag.Usage = usage
flag.Parse()
if *dynobj != "" {
// cgo -dynimport is essentially a separate helper command
// built into the cgo binary. It scans a gcc-produced executable
// and dumps information about the imported symbols and the
// imported libraries. The 'go build' rules for cgo prepare an
// appropriate executable and then use its import information
// instead of needing to make the linkers duplicate all the
// specialized knowledge gcc has about where to look for imported
// symbols and which ones to use.
dynimport(*dynobj)
return
}
if *godefs {
// Generating definitions pulled from header files,
// to be checked into Go repositories.
// Line numbers are just noise.
conf.Mode &^= printer.SourcePos
}
args := flag.Args()
if len(args) < 1 {
usage()
}
// Find first arg that looks like a go file and assume everything before
// that are options to pass to gcc.
var i int
for i = len(args); i > 0; i-- {
if !strings.HasSuffix(args[i-1], ".go") {
break
}
}
if i == len(args) {
usage()
}
goFiles := args[i:]
p := newPackage(args[:i])
// Record CGO_LDFLAGS from the environment for external linking.
if ldflags := os.Getenv("CGO_LDFLAGS"); ldflags != "" {
args, err := splitQuoted(ldflags)
if err != nil {
fatalf("bad CGO_LDFLAGS: %q (%s)", ldflags, err)
}
p.addToFlag("LDFLAGS", args)
}
// Need a unique prefix for the global C symbols that
// we use to coordinate between gcc and ourselves.
// We already put _cgo_ at the beginning, so the main
// concern is other cgo wrappers for the same functions.
// Use the beginning of the md5 of the input to disambiguate.
h := md5.New()
for _, input := range goFiles {
f, err := os.Open(input)
if err != nil {
fatalf("%s", err)
}
io.Copy(h, f)
f.Close()
}
cPrefix = fmt.Sprintf("_%x", h.Sum(nil)[0:6])
fs := make([]*File, len(goFiles))
for i, input := range goFiles {
f := new(File)
f.ReadGo(input)
f.DiscardCgoDirectives()
fs[i] = f
}
if *objDir == "" {
// make sure that _obj directory exists, so that we can write
// all the output files there.
os.Mkdir("_obj", 0777)
*objDir = "_obj"
}
*objDir += string(filepath.Separator)
for i, input := range goFiles {
f := fs[i]
p.Translate(f)
for _, cref := range f.Ref {
switch cref.Context {
case "call", "call2":
if cref.Name.Kind != "type" {
break
}
*cref.Expr = cref.Name.Type.Go
}
}
if nerrors > 0 {
os.Exit(2)
}
pkg := f.Package
if dir := os.Getenv("CGOPKGPATH"); dir != "" {
pkg = filepath.Join(dir, pkg)
}
p.PackagePath = pkg
p.Record(f)
if *godefs {
os.Stdout.WriteString(p.godefs(f, input))
} else {
p.writeOutput(f, input)
}
}
if !*godefs {
p.writeDefs()
}
if nerrors > 0 {
os.Exit(2)
}
}
// newPackage returns a new Package that will invoke
// gcc with the additional arguments specified in args.
func newPackage(args []string) *Package {
goarch = runtime.GOARCH
if s := os.Getenv("GOARCH"); s != "" {
goarch = s
}
goos = runtime.GOOS
if s := os.Getenv("GOOS"); s != "" {
goos = s
}
ptrSize := ptrSizeMap[goarch]
if ptrSize == 0 {
fatalf("unknown ptrSize for $GOARCH %q", goarch)
}
intSize := intSizeMap[goarch]
if intSize == 0 {
fatalf("unknown intSize for $GOARCH %q", goarch)
}
// Reset locale variables so gcc emits English errors [sic].
os.Setenv("LANG", "en_US.UTF-8")
os.Setenv("LC_ALL", "C")
p := &Package{
PtrSize: ptrSize,
IntSize: intSize,
CgoFlags: make(map[string][]string),
Written: make(map[string]bool),
}
p.addToFlag("CFLAGS", args)
return p
}
// Record what needs to be recorded about f.
func (p *Package) Record(f *File) {
if p.PackageName == "" {
p.PackageName = f.Package
} else if p.PackageName != f.Package {
error_(token.NoPos, "inconsistent package names: %s, %s", p.PackageName, f.Package)
}
if p.Name == nil {
p.Name = f.Name
} else {
for k, v := range f.Name {
if p.Name[k] == nil {
p.Name[k] = v
} else if !reflect.DeepEqual(p.Name[k], v) {
error_(token.NoPos, "inconsistent definitions for C.%s", fixGo(k))
}
}
}
if f.ExpFunc != nil {
p.ExpFunc = append(p.ExpFunc, f.ExpFunc...)
p.Preamble += "\n" + f.Preamble
}
p.Decl = append(p.Decl, f.AST.Decls...)
}