diff --git a/src/cmd/cgo/doc.go b/src/cmd/cgo/doc.go index b3aa9aded29..064725c1d5d 100644 --- a/src/cmd/cgo/doc.go +++ b/src/cmd/cgo/doc.go @@ -35,9 +35,17 @@ systems. For example: // #include import "C" -C identifiers or field names that are keywords in Go can be -accessed by prefixing them with an underscore: if x points at -a C struct with a field named "type", x._type accesses the field. +Alternatively, CFLAGS and LDFLAGS may be obtained via the pkg-config +tool using a '#cgo pkg-config:' directive followed by the package names. +For example: + + // #cgo pkg-config: png cairo + // #include + import "C" + +Within the Go file, C identifiers or field names that are keywords in Go +can be accessed by prefixing them with an underscore: if x points at a C +struct with a field named "type", x._type accesses the field. The standard C numeric types are available under the names C.char, C.schar (signed char), C.uchar (unsigned char), diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go index ac656134598..1fa8dd16611 100644 --- a/src/cmd/cgo/gcc.go +++ b/src/cmd/cgo/gcc.go @@ -100,27 +100,76 @@ NextLine: fatalf("%s: bad #cgo option: %s", srcfile, fields[0]) } - if k != "CFLAGS" && k != "LDFLAGS" { - fatalf("%s: unsupported #cgo option %s", srcfile, k) + args, err := splitQuoted(fields[1]) + if err != nil { + fatalf("%s: bad #cgo option %s: %s", srcfile, k, err) } - v := strings.TrimSpace(fields[1]) - args, err := splitQuoted(v) - if err != nil { - fatalf("%s: bad #cgo option %s: %s", srcfile, k, err.String()) - } - if oldv, ok := p.CgoFlags[k]; ok { - p.CgoFlags[k] = oldv + " " + v - } else { - p.CgoFlags[k] = v - } - if k == "CFLAGS" { - p.GccOptions = append(p.GccOptions, args...) + switch k { + + case "CFLAGS", "LDFLAGS": + p.addToFlag(k, args) + + case "pkg-config": + cflags, ldflags, err := pkgConfig(args) + if err != nil { + fatalf("%s: bad #cgo option %s: %s", srcfile, k, err) + } + p.addToFlag("CFLAGS", cflags) + p.addToFlag("LDFLAGS", ldflags) + + default: + fatalf("%s: unsupported #cgo option %s", srcfile, k) + } } f.Preamble = strings.Join(linesOut, "\n") } +// addToFlag appends args to flag. All flags are later written out onto the +// _cgo_flags file for the build system to use. +func (p *Package) addToFlag(flag string, args []string) { + if oldv, ok := p.CgoFlags[flag]; ok { + p.CgoFlags[flag] = oldv + " " + strings.Join(args, " ") + } else { + p.CgoFlags[flag] = strings.Join(args, " ") + } + if flag == "CFLAGS" { + // We'll also need these when preprocessing for dwarf information. + p.GccOptions = append(p.GccOptions, args...) + } +} + +// pkgConfig runs pkg-config and extracts --libs and --cflags information +// for packages. +func pkgConfig(packages []string) (cflags, ldflags []string, err os.Error) { + for _, name := range packages { + if len(name) == 0 || !safeName(name) || name[0] == '-' { + return nil, nil, os.NewError(fmt.Sprintf("invalid name: %q", name)) + } + } + + args := append([]string{"pkg-config", "--cflags"}, packages...) + stdout, stderr, ok := run(nil, args) + if !ok { + os.Stderr.Write(stderr) + return nil, nil, os.NewError("pkg-config failed") + } + cflags, err = splitQuoted(string(stdout)) + if err != nil { + return + } + + args = append([]string{"pkg-config", "--libs"}, packages...) + stdout, stderr, ok = run(nil, args) + if !ok { + os.Stderr.Write(stderr) + return nil, nil, os.NewError("pkg-config failed") + } + ldflags, err = splitQuoted(string(stdout)) + return +} + // splitQuoted splits the string s around each instance of one or more consecutive // white space characters while taking into account quotes and escaping, and // returns an array of substrings of s or an empty list if s contains only white space. @@ -182,6 +231,20 @@ func splitQuoted(s string) (r []string, err os.Error) { return args, err } +var safeBytes = []byte("+-./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz") + +func safeName(s string) bool { + if s == "" { + return false + } + for i := 0; i < len(s); i++ { + if c := s[i]; c < 0x80 && bytes.IndexByte(safeBytes, c) < 0 { + return false + } + } + return true +} + // Translate rewrites f.AST, the original Go input, to remove // references to the imported package C, replacing them with // references to the equivalent Go types, functions, and variables.