mirror of
https://github.com/golang/go
synced 2024-11-06 08:16:11 -07:00
[dev.link] cmd/link: remove old host object loader vestiges
Change-Id: Ic27d1d62d1b411fa7cdf66af44f9843aa644e776 Reviewed-on: https://go-review.googlesource.com/c/go/+/217558 Run-TryBot: Jeremy Faller <jeremy@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Jeremy Faller
parent
9857e5c815
commit
1152c6d3f0
@ -151,153 +151,8 @@ func loadcgo(ctxt *Link, file string, pkg string, p string) {
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}
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// Set symbol attributes or flags based on cgo directives.
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func setCgoAttr(ctxt *Link, lookup func(string, int) *sym.Symbol, file string, pkg string, directives [][]string) {
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for _, f := range directives {
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switch f[0] {
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case "cgo_import_dynamic":
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if len(f) < 2 || len(f) > 4 {
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break
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}
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local := f[1]
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remote := local
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if len(f) > 2 {
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remote = f[2]
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}
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lib := ""
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if len(f) > 3 {
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lib = f[3]
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}
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if *FlagD {
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fmt.Fprintf(os.Stderr, "%s: %s: cannot use dynamic imports with -d flag\n", os.Args[0], file)
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nerrors++
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return
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}
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if local == "_" && remote == "_" {
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// allow #pragma dynimport _ _ "foo.so"
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// to force a link of foo.so.
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havedynamic = 1
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if ctxt.HeadType == objabi.Hdarwin {
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machoadddynlib(lib, ctxt.LinkMode)
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} else {
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dynlib = append(dynlib, lib)
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}
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continue
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}
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local = expandpkg(local, pkg)
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q := ""
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if i := strings.Index(remote, "#"); i >= 0 {
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remote, q = remote[:i], remote[i+1:]
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}
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s := lookup(local, 0)
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if s.Type == 0 || s.Type == sym.SXREF || s.Type == sym.SBSS || s.Type == sym.SNOPTRBSS || s.Type == sym.SHOSTOBJ {
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s.SetDynimplib(lib)
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s.SetExtname(remote)
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s.SetDynimpvers(q)
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if s.Type != sym.SHOSTOBJ {
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s.Type = sym.SDYNIMPORT
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}
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havedynamic = 1
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}
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continue
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case "cgo_import_static":
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if len(f) != 2 {
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break
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}
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local := f[1]
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s := lookup(local, 0)
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s.Type = sym.SHOSTOBJ
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s.Size = 0
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continue
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case "cgo_export_static", "cgo_export_dynamic":
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if len(f) < 2 || len(f) > 3 {
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break
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}
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local := f[1]
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remote := local
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if len(f) > 2 {
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remote = f[2]
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}
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local = expandpkg(local, pkg)
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// The compiler arranges for an ABI0 wrapper
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// to be available for all cgo-exported
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// functions. Link.loadlib will resolve any
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// ABI aliases we find here (since we may not
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// yet know it's an alias).
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s := lookup(local, 0)
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switch ctxt.BuildMode {
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case BuildModeCShared, BuildModeCArchive, BuildModePlugin:
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if s == lookup("main", 0) {
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continue
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}
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}
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// export overrides import, for openbsd/cgo.
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// see issue 4878.
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if s.Dynimplib() != "" {
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s.ResetDyninfo()
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s.SetExtname("")
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s.Type = 0
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}
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if !s.Attr.CgoExport() {
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s.SetExtname(remote)
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} else if s.Extname() != remote {
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fmt.Fprintf(os.Stderr, "%s: conflicting cgo_export directives: %s as %s and %s\n", os.Args[0], s.Name, s.Extname(), remote)
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nerrors++
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return
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}
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if f[0] == "cgo_export_static" {
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s.Attr |= sym.AttrCgoExportStatic
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} else {
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s.Attr |= sym.AttrCgoExportDynamic
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}
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continue
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case "cgo_dynamic_linker":
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if len(f) != 2 {
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break
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}
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if *flagInterpreter == "" {
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if interpreter != "" && interpreter != f[1] {
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fmt.Fprintf(os.Stderr, "%s: conflict dynlinker: %s and %s\n", os.Args[0], interpreter, f[1])
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nerrors++
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return
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}
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interpreter = f[1]
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}
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continue
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case "cgo_ldflag":
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if len(f) != 2 {
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break
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}
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ldflag = append(ldflag, f[1])
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continue
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}
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fmt.Fprintf(os.Stderr, "%s: %s: invalid cgo directive: %q\n", os.Args[0], file, f)
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nerrors++
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}
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}
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// Set symbol attributes or flags based on cgo directives.
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// This version works with loader.Sym and not sym.Symbol.
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// Any newly discovered HOSTOBJ syms are added to 'hostObjSyms'.
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func setCgoAttr2(ctxt *Link, lookup func(string, int) loader.Sym, file string, pkg string, directives [][]string, hostObjSyms map[loader.Sym]struct{}) {
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func setCgoAttr(ctxt *Link, lookup func(string, int) loader.Sym, file string, pkg string, directives [][]string, hostObjSyms map[loader.Sym]struct{}) {
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l := ctxt.loader
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for _, f := range directives {
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switch f[0] {
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@ -459,7 +459,7 @@ func (ctxt *Link) loadlib() {
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ctxt.loader.LoadRefs(ctxt.Arch, ctxt.Syms)
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// Process cgo directives (has to be done before host object loading).
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ctxt.loadcgodirectives(ctxt.loaderSupport())
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ctxt.loadcgodirectives()
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// Conditionally load host objects, or setup for external linking.
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hostobjs(ctxt)
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@ -469,25 +469,10 @@ func (ctxt *Link) loadlib() {
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// If we have any undefined symbols in external
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// objects, try to read them from the libgcc file.
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any := false
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if ctxt.loaderSupport() {
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undefs := ctxt.loader.UndefinedRelocTargets(1)
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if len(undefs) > 0 {
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any = true
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}
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} else {
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for _, s := range ctxt.loader.Syms {
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if s == nil {
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continue
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}
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for i := range s.R {
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r := &s.R[i] // Copying sym.Reloc has measurable impact on performance
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if r.Sym != nil && r.Sym.Type == sym.SXREF && r.Sym.Name != ".got" {
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any = true
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break
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}
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}
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}
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}
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if any {
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if *flagLibGCC == "" {
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*flagLibGCC = ctxt.findLibPathCmd("--print-libgcc-file-name", "libgcc")
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@ -563,15 +548,13 @@ func setupdynexp(ctxt *Link) {
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ctxt.cgo_export_dynamic = nil
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}
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// loadcgodirectives reads the previously discovered cgo directives,
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// creating symbols (either sym.Symbol or loader.Sym) in preparation
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// for host object loading or use later in the link.
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func (ctxt *Link) loadcgodirectives(useLoader bool) {
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if useLoader {
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// loadcgodirectives reads the previously discovered cgo directives, creating
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// symbols in preparation for host object loading or use later in the link.
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func (ctxt *Link) loadcgodirectives() {
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l := ctxt.loader
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hostObjSyms := make(map[loader.Sym]struct{})
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for _, d := range ctxt.cgodata {
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setCgoAttr2(ctxt, ctxt.loader.LookupOrCreateSym, d.file, d.pkg, d.directives, hostObjSyms)
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setCgoAttr(ctxt, ctxt.loader.LookupOrCreateSym, d.file, d.pkg, d.directives, hostObjSyms)
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}
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ctxt.cgodata = nil
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@ -593,35 +576,6 @@ func (ctxt *Link) loadcgodirectives(useLoader bool) {
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}
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}
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}
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} else {
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// In newobj mode, we typically create sym.Symbols later therefore
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// also set cgo attributes later. However, for internal cgo linking,
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// the host object loaders still work with sym.Symbols (for now),
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// and they need cgo attributes set to work properly. So process
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// them now.
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for _, d := range ctxt.cgodata {
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setCgoAttr(ctxt, ctxt.loader.LookupOrCreate, d.file, d.pkg, d.directives)
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}
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ctxt.cgodata = nil
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if ctxt.LinkMode == LinkInternal {
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// Drop all the cgo_import_static declarations.
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// Turns out we won't be needing them.
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for _, s := range ctxt.loader.Syms {
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if s != nil && s.Type == sym.SHOSTOBJ {
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// If a symbol was marked both
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// cgo_import_static and cgo_import_dynamic,
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// then we want to make it cgo_import_dynamic
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// now.
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if s.Extname() != "" && s.Dynimplib() != "" && !s.Attr.CgoExport() {
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s.Type = sym.SDYNIMPORT
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} else {
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s.Type = 0
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}
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}
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}
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}
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}
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}
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// Set up flags and special symbols depending on the platform build mode.
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@ -758,130 +712,6 @@ func (ctxt *Link) linksetup() {
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}
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}
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// Set up flags and special symbols depending on the platform build mode.
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func (ctxt *Link) linksetupold() {
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switch ctxt.BuildMode {
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case BuildModeCShared, BuildModePlugin:
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s := ctxt.Syms.Lookup("runtime.islibrary", 0)
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s.Type = sym.SNOPTRDATA
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s.Attr |= sym.AttrDuplicateOK
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s.AddUint8(1)
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case BuildModeCArchive:
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s := ctxt.Syms.Lookup("runtime.isarchive", 0)
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s.Type = sym.SNOPTRDATA
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s.Attr |= sym.AttrDuplicateOK
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s.AddUint8(1)
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}
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// Recalculate pe parameters now that we have ctxt.LinkMode set.
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if ctxt.HeadType == objabi.Hwindows {
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Peinit(ctxt)
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}
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if ctxt.HeadType == objabi.Hdarwin && ctxt.LinkMode == LinkExternal {
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*FlagTextAddr = 0
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}
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// If there are no dynamic libraries needed, gcc disables dynamic linking.
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// Because of this, glibc's dynamic ELF loader occasionally (like in version 2.13)
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// assumes that a dynamic binary always refers to at least one dynamic library.
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// Rather than be a source of test cases for glibc, disable dynamic linking
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// the same way that gcc would.
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//
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// Exception: on OS X, programs such as Shark only work with dynamic
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// binaries, so leave it enabled on OS X (Mach-O) binaries.
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// Also leave it enabled on Solaris which doesn't support
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// statically linked binaries.
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if ctxt.BuildMode == BuildModeExe {
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if havedynamic == 0 && ctxt.HeadType != objabi.Hdarwin && ctxt.HeadType != objabi.Hsolaris {
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*FlagD = true
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}
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}
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if ctxt.LinkMode == LinkExternal && ctxt.Arch.Family == sys.PPC64 && objabi.GOOS != "aix" {
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toc := ctxt.Syms.Lookup(".TOC.", 0)
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toc.Type = sym.SDYNIMPORT
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}
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// The Android Q linker started to complain about underalignment of the our TLS
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// section. We don't actually use the section on android, so dont't
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// generate it.
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if objabi.GOOS != "android" {
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tlsg := ctxt.Syms.Lookup("runtime.tlsg", 0)
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// runtime.tlsg is used for external linking on platforms that do not define
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// a variable to hold g in assembly (currently only intel).
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if tlsg.Type == 0 {
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tlsg.Type = sym.STLSBSS
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tlsg.Size = int64(ctxt.Arch.PtrSize)
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} else if tlsg.Type != sym.SDYNIMPORT {
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Errorf(nil, "runtime declared tlsg variable %v", tlsg.Type)
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}
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tlsg.Attr |= sym.AttrReachable
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ctxt.Tlsg = tlsg
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}
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var moduledata *sym.Symbol
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if ctxt.BuildMode == BuildModePlugin {
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moduledata = ctxt.Syms.Lookup("local.pluginmoduledata", 0)
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moduledata.Attr |= sym.AttrLocal
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} else {
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moduledata = ctxt.Syms.Lookup("runtime.firstmoduledata", 0)
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}
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if moduledata.Type != 0 && moduledata.Type != sym.SDYNIMPORT {
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// If the module (toolchain-speak for "executable or shared
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// library") we are linking contains the runtime package, it
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// will define the runtime.firstmoduledata symbol and we
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// truncate it back to 0 bytes so we can define its entire
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// contents in symtab.go:symtab().
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moduledata.Size = 0
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// In addition, on ARM, the runtime depends on the linker
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// recording the value of GOARM.
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if ctxt.Arch.Family == sys.ARM {
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s := ctxt.Syms.Lookup("runtime.goarm", 0)
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s.Type = sym.SDATA
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s.Size = 0
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s.AddUint8(uint8(objabi.GOARM))
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}
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if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) {
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s := ctxt.Syms.Lookup("runtime.framepointer_enabled", 0)
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s.Type = sym.SDATA
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s.Size = 0
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s.AddUint8(1)
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}
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} else {
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// If OTOH the module does not contain the runtime package,
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// create a local symbol for the moduledata.
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moduledata = ctxt.Syms.Lookup("local.moduledata", 0)
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moduledata.Attr |= sym.AttrLocal
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}
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// In all cases way we mark the moduledata as noptrdata to hide it from
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// the GC.
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moduledata.Type = sym.SNOPTRDATA
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moduledata.Attr |= sym.AttrReachable
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ctxt.Moduledata = moduledata
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// If package versioning is required, generate a hash of the
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// packages used in the link.
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if ctxt.BuildMode == BuildModeShared || ctxt.BuildMode == BuildModePlugin || ctxt.CanUsePlugins() {
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for _, lib := range ctxt.Library {
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if lib.Shlib == "" {
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genhash(ctxt, lib)
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}
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}
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}
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if ctxt.Arch == sys.Arch386 && ctxt.HeadType != objabi.Hwindows {
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if (ctxt.BuildMode == BuildModeCArchive && ctxt.IsELF) || ctxt.BuildMode == BuildModeCShared || ctxt.BuildMode == BuildModePIE || ctxt.DynlinkingGo() {
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got := ctxt.Syms.Lookup("_GLOBAL_OFFSET_TABLE_", 0)
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got.Type = sym.SDYNIMPORT
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got.Attr |= sym.AttrReachable
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}
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}
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}
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// mangleTypeSym shortens the names of symbols that represent Go types
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// if they are visible in the symbol table.
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//
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@ -100,10 +100,6 @@ var (
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benchmarkFlag = flag.String("benchmark", "", "set to 'mem' or 'cpu' to enable phase benchmarking")
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)
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func (ctxt *Link) loaderSupport() bool {
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return true //ctxt.IsELF || ctxt.HeadType == objabi.Hdarwin || ctxt.HeadType == objabi.Haix
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}
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// Main is the main entry point for the linker code.
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func Main(arch *sys.Arch, theArch Arch) {
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thearch = theArch
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@ -235,18 +231,12 @@ func Main(arch *sys.Arch, theArch Arch) {
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bench.Start("deadcode")
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deadcode(ctxt)
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if ctxt.loaderSupport() {
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bench.Start("linksetup")
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ctxt.linksetup()
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}
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bench.Start("loadlibfull")
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ctxt.loadlibfull() // XXX do it here for now
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if !ctxt.loaderSupport() {
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bench.Start("linksetupold")
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ctxt.linksetupold()
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}
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bench.Start("dostrdata")
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ctxt.dostrdata()
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bench.Start("dwarfGenerateDebugInfo")
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