--- /dev/null
+// Copyright 2013 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.
+
+// Except for this comment and the import path, this file is a verbatim copy of the file
+// with the same name in $GOROOT/src/go/internal/gccgoimporter.
+
+// Package gccgoimporter implements Import for gccgo-generated object files.
+package gccgoimporter // import "golang.org/x/tools/go/internal/gccgoimporter"
+
+import (
+ "debug/elf"
+ "fmt"
+ "go/types"
+ "io"
+ "os"
+ "path/filepath"
+ "strings"
+)
+
+// A PackageInit describes an imported package that needs initialization.
+type PackageInit struct {
+ Name string // short package name
+ InitFunc string // name of init function
+ Priority int // priority of init function, see InitData.Priority
+}
+
+// The gccgo-specific init data for a package.
+type InitData struct {
+ // Initialization priority of this package relative to other packages.
+ // This is based on the maximum depth of the package's dependency graph;
+ // it is guaranteed to be greater than that of its dependencies.
+ Priority int
+
+ // The list of packages which this package depends on to be initialized,
+ // including itself if needed. This is the subset of the transitive closure of
+ // the package's dependencies that need initialization.
+ Inits []PackageInit
+}
+
+// Locate the file from which to read export data.
+// This is intended to replicate the logic in gofrontend.
+func findExportFile(searchpaths []string, pkgpath string) (string, error) {
+ for _, spath := range searchpaths {
+ pkgfullpath := filepath.Join(spath, pkgpath)
+ pkgdir, name := filepath.Split(pkgfullpath)
+
+ for _, filepath := range [...]string{
+ pkgfullpath,
+ pkgfullpath + ".gox",
+ pkgdir + "lib" + name + ".so",
+ pkgdir + "lib" + name + ".a",
+ pkgfullpath + ".o",
+ } {
+ fi, err := os.Stat(filepath)
+ if err == nil && !fi.IsDir() {
+ return filepath, nil
+ }
+ }
+ }
+
+ return "", fmt.Errorf("%s: could not find export data (tried %s)", pkgpath, strings.Join(searchpaths, ":"))
+}
+
+const (
+ gccgov1Magic = "v1;\n"
+ gccgov2Magic = "v2;\n"
+ gccgov3Magic = "v3;\n"
+ goimporterMagic = "\n$$ "
+ archiveMagic = "!<ar"
+)
+
+// Opens the export data file at the given path. If this is an ELF file,
+// searches for and opens the .go_export section. If this is an archive,
+// reads the export data from the first member, which is assumed to be an ELF file.
+// This is intended to replicate the logic in gofrontend.
+func openExportFile(fpath string) (reader io.ReadSeeker, closer io.Closer, err error) {
+ f, err := os.Open(fpath)
+ if err != nil {
+ return
+ }
+ closer = f
+ defer func() {
+ if err != nil && closer != nil {
+ f.Close()
+ }
+ }()
+
+ var magic [4]byte
+ _, err = f.ReadAt(magic[:], 0)
+ if err != nil {
+ return
+ }
+
+ var elfreader io.ReaderAt
+ switch string(magic[:]) {
+ case gccgov1Magic, gccgov2Magic, gccgov3Magic, goimporterMagic:
+ // Raw export data.
+ reader = f
+ return
+
+ case archiveMagic:
+ reader, err = arExportData(f)
+ return
+
+ default:
+ elfreader = f
+ }
+
+ ef, err := elf.NewFile(elfreader)
+ if err != nil {
+ return
+ }
+
+ sec := ef.Section(".go_export")
+ if sec == nil {
+ err = fmt.Errorf("%s: .go_export section not found", fpath)
+ return
+ }
+
+ reader = sec.Open()
+ return
+}
+
+// An Importer resolves import paths to Packages. The imports map records
+// packages already known, indexed by package path.
+// An importer must determine the canonical package path and check imports
+// to see if it is already present in the map. If so, the Importer can return
+// the map entry. Otherwise, the importer must load the package data for the
+// given path into a new *Package, record it in imports map, and return the
+// package.
+type Importer func(imports map[string]*types.Package, path, srcDir string, lookup func(string) (io.ReadCloser, error)) (*types.Package, error)
+
+func GetImporter(searchpaths []string, initmap map[*types.Package]InitData) Importer {
+ return func(imports map[string]*types.Package, pkgpath, srcDir string, lookup func(string) (io.ReadCloser, error)) (pkg *types.Package, err error) {
+ // TODO(gri): Use srcDir.
+ // Or not. It's possible that srcDir will fade in importance as
+ // the go command and other tools provide a translation table
+ // for relative imports (like ./foo or vendored imports).
+ if pkgpath == "unsafe" {
+ return types.Unsafe, nil
+ }
+
+ var reader io.ReadSeeker
+ var fpath string
+ var rc io.ReadCloser
+ if lookup != nil {
+ if p := imports[pkgpath]; p != nil && p.Complete() {
+ return p, nil
+ }
+ rc, err = lookup(pkgpath)
+ if err != nil {
+ return nil, err
+ }
+ }
+ if rc != nil {
+ defer rc.Close()
+ rs, ok := rc.(io.ReadSeeker)
+ if !ok {
+ return nil, fmt.Errorf("gccgo importer requires lookup to return an io.ReadSeeker, have %T", rc)
+ }
+ reader = rs
+ fpath = "<lookup " + pkgpath + ">"
+ // Take name from Name method (like on os.File) if present.
+ if n, ok := rc.(interface{ Name() string }); ok {
+ fpath = n.Name()
+ }
+ } else {
+ fpath, err = findExportFile(searchpaths, pkgpath)
+ if err != nil {
+ return nil, err
+ }
+
+ r, closer, err := openExportFile(fpath)
+ if err != nil {
+ return nil, err
+ }
+ if closer != nil {
+ defer closer.Close()
+ }
+ reader = r
+ }
+
+ var magics string
+ magics, err = readMagic(reader)
+ if err != nil {
+ return
+ }
+
+ if magics == archiveMagic {
+ reader, err = arExportData(reader)
+ if err != nil {
+ return
+ }
+ magics, err = readMagic(reader)
+ if err != nil {
+ return
+ }
+ }
+
+ switch magics {
+ case gccgov1Magic, gccgov2Magic, gccgov3Magic:
+ var p parser
+ p.init(fpath, reader, imports)
+ pkg = p.parsePackage()
+ if initmap != nil {
+ initmap[pkg] = p.initdata
+ }
+
+ // Excluded for now: Standard gccgo doesn't support this import format currently.
+ // case goimporterMagic:
+ // var data []byte
+ // data, err = ioutil.ReadAll(reader)
+ // if err != nil {
+ // return
+ // }
+ // var n int
+ // n, pkg, err = importer.ImportData(imports, data)
+ // if err != nil {
+ // return
+ // }
+
+ // if initmap != nil {
+ // suffixreader := bytes.NewReader(data[n:])
+ // var p parser
+ // p.init(fpath, suffixreader, nil)
+ // p.parseInitData()
+ // initmap[pkg] = p.initdata
+ // }
+
+ default:
+ err = fmt.Errorf("unrecognized magic string: %q", magics)
+ }
+
+ return
+ }
+}
+
+// readMagic reads the four bytes at the start of a ReadSeeker and
+// returns them as a string.
+func readMagic(reader io.ReadSeeker) (string, error) {
+ var magic [4]byte
+ if _, err := reader.Read(magic[:]); err != nil {
+ return "", err
+ }
+ if _, err := reader.Seek(0, io.SeekStart); err != nil {
+ return "", err
+ }
+ return string(magic[:]), nil
+}
projects / dotfiles / .git / blobdiff