func elfsetupplt() {
plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
if plt.Size == 0 {
// pushl got+4
ld.Adduint8(ld.Ctxt, plt, 0xff)
ld.Adduint8(ld.Ctxt, plt, 0x35)
ld.Addaddrplus(ld.Ctxt, plt, got, 4)
// jmp *got+8
ld.Adduint8(ld.Ctxt, plt, 0xff)
ld.Adduint8(ld.Ctxt, plt, 0x25)
ld.Addaddrplus(ld.Ctxt, plt, got, 8)
// zero pad
ld.Adduint32(ld.Ctxt, plt, 0)
// assume got->size == 0 too
ld.Addaddrplus(ld.Ctxt, got, ld.Linklookup(ld.Ctxt, ".dynamic", 0), 0)
ld.Adduint32(ld.Ctxt, got, 0)
ld.Adduint32(ld.Ctxt, got, 0)
}
}
func elfsetupplt() {
plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
if plt.Size == 0 {
// pushq got+8(IP)
ld.Adduint8(ld.Ctxt, plt, 0xff)
ld.Adduint8(ld.Ctxt, plt, 0x35)
ld.Addpcrelplus(ld.Ctxt, plt, got, 8)
// jmpq got+16(IP)
ld.Adduint8(ld.Ctxt, plt, 0xff)
ld.Adduint8(ld.Ctxt, plt, 0x25)
ld.Addpcrelplus(ld.Ctxt, plt, got, 16)
// nopl 0(AX)
ld.Adduint32(ld.Ctxt, plt, 0x00401f0f)
// assume got->size == 0 too
ld.Addaddrplus(ld.Ctxt, got, ld.Linklookup(ld.Ctxt, ".dynamic", 0), 0)
ld.Adduint64(ld.Ctxt, got, 0)
ld.Adduint64(ld.Ctxt, got, 0)
}
}
func adddynsym(ctxt *ld.Link, s *ld.LSym) {
if s.Dynid >= 0 {
return
}
if ld.Iself {
s.Dynid = int32(ld.Nelfsym)
ld.Nelfsym++
d := ld.Linklookup(ctxt, ".dynsym", 0)
name := s.Extname
ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name)))
/* type */
t := ld.STB_GLOBAL << 4
if s.Cgoexport != 0 && s.Type&ld.SMASK == ld.STEXT {
t |= ld.STT_FUNC
} else {
t |= ld.STT_OBJECT
}
ld.Adduint8(ctxt, d, uint8(t))
/* reserved */
ld.Adduint8(ctxt, d, 0)
/* section where symbol is defined */
if s.Type == ld.SDYNIMPORT {
ld.Adduint16(ctxt, d, ld.SHN_UNDEF)
} else {
ld.Adduint16(ctxt, d, 1)
}
/* value */
if s.Type == ld.SDYNIMPORT {
ld.Adduint64(ctxt, d, 0)
} else {
ld.Addaddr(ctxt, d, s)
}
/* size of object */
ld.Adduint64(ctxt, d, uint64(s.Size))
if s.Cgoexport&ld.CgoExportDynamic == 0 && s.Dynimplib != "" && needlib(s.Dynimplib) != 0 {
ld.Elfwritedynent(ld.Linklookup(ctxt, ".dynamic", 0), ld.DT_NEEDED, uint64(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), s.Dynimplib)))
}
} else if ld.HEADTYPE == ld.Hdarwin {
ld.Diag("adddynsym: missed symbol %s (%s)", s.Name, s.Extname)
} else if ld.HEADTYPE == ld.Hwindows {
} else // already taken care of
{
ld.Diag("adddynsym: unsupported binary format")
}
}
func adddynsym(ctxt *ld.Link, s *ld.LSym) {
if s.Dynid >= 0 {
return
}
if ld.Iself {
s.Dynid = int32(ld.Nelfsym)
ld.Nelfsym++
d := ld.Linklookup(ctxt, ".dynsym", 0)
/* name */
name := s.Extname
ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name)))
/* value */
if s.Type == ld.SDYNIMPORT {
ld.Adduint32(ctxt, d, 0)
} else {
ld.Addaddr(ctxt, d, s)
}
/* size */
ld.Adduint32(ctxt, d, 0)
/* type */
t := ld.STB_GLOBAL << 4
if s.Cgoexport != 0 && s.Type&ld.SMASK == ld.STEXT {
t |= ld.STT_FUNC
} else {
t |= ld.STT_OBJECT
}
ld.Adduint8(ctxt, d, uint8(t))
ld.Adduint8(ctxt, d, 0)
/* shndx */
if s.Type == ld.SDYNIMPORT {
ld.Adduint16(ctxt, d, ld.SHN_UNDEF)
} else {
ld.Adduint16(ctxt, d, 1)
}
} else if ld.HEADTYPE == ld.Hdarwin {
ld.Diag("adddynsym: missed symbol %s (%s)", s.Name, s.Extname)
} else if ld.HEADTYPE == ld.Hwindows {
} else // already taken care of
{
ld.Diag("adddynsym: unsupported binary format")
}
}
func adddynsym(ctxt *ld.Link, s *ld.LSym) {
if s.Dynid >= 0 {
return
}
if ld.Iself {
s.Dynid = int32(ld.Nelfsym)
ld.Nelfsym++
d := ld.Linklookup(ctxt, ".dynsym", 0)
/* name */
name := s.Extname
ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name)))
/* value */
if s.Type == ld.SDYNIMPORT {
ld.Adduint32(ctxt, d, 0)
} else {
ld.Addaddr(ctxt, d, s)
}
/* size */
ld.Adduint32(ctxt, d, 0)
/* type */
t := ld.STB_GLOBAL << 4
if (s.Cgoexport&ld.CgoExportDynamic != 0) && s.Type&ld.SMASK == ld.STEXT {
t |= ld.STT_FUNC
} else {
t |= ld.STT_OBJECT
}
ld.Adduint8(ctxt, d, uint8(t))
ld.Adduint8(ctxt, d, 0)
/* shndx */
if s.Type == ld.SDYNIMPORT {
ld.Adduint16(ctxt, d, ld.SHN_UNDEF)
} else {
ld.Adduint16(ctxt, d, 1)
}
} else {
ld.Diag("adddynsym: unsupported binary format")
}
}
func adddynsym(ctxt *ld.Link, s *ld.LSym) {
if s.Dynid >= 0 {
return
}
if ld.Iself {
s.Dynid = int32(ld.Nelfsym)
ld.Nelfsym++
d := ld.Linklookup(ctxt, ".dynsym", 0)
name := s.Extname
ld.Adduint32(ctxt, d, uint32(ld.Addstring(ld.Linklookup(ctxt, ".dynstr", 0), name)))
/* type */
t := ld.STB_GLOBAL << 4
if s.Cgoexport != 0 && s.Type&ld.SMASK == ld.STEXT {
t |= ld.STT_FUNC
} else {
t |= ld.STT_OBJECT
}
ld.Adduint8(ctxt, d, uint8(t))
/* reserved */
ld.Adduint8(ctxt, d, 0)
/* section where symbol is defined */
if s.Type == ld.SDYNIMPORT {
ld.Adduint16(ctxt, d, ld.SHN_UNDEF)
} else {
ld.Adduint16(ctxt, d, 1)
}
/* value */
if s.Type == ld.SDYNIMPORT {
ld.Adduint64(ctxt, d, 0)
} else {
ld.Addaddr(ctxt, d, s)
}
/* size of object */
ld.Adduint64(ctxt, d, uint64(s.Size))
} else {
ld.Diag("adddynsym: unsupported binary format")
}
}
func addpltsym(ctxt *ld.Link, s *ld.LSym) {
if s.Plt >= 0 {
return
}
adddynsym(ctxt, s)
if ld.Iself {
plt := ld.Linklookup(ctxt, ".plt", 0)
got := ld.Linklookup(ctxt, ".got.plt", 0)
rel := ld.Linklookup(ctxt, ".rel.plt", 0)
if plt.Size == 0 {
elfsetupplt()
}
// jmpq *got+size
ld.Adduint8(ctxt, plt, 0xff)
ld.Adduint8(ctxt, plt, 0x25)
ld.Addaddrplus(ctxt, plt, got, got.Size)
// add to got: pointer to current pos in plt
ld.Addaddrplus(ctxt, got, plt, plt.Size)
// pushl $x
ld.Adduint8(ctxt, plt, 0x68)
ld.Adduint32(ctxt, plt, uint32(rel.Size))
// jmp .plt
ld.Adduint8(ctxt, plt, 0xe9)
ld.Adduint32(ctxt, plt, uint32(-(plt.Size + 4)))
// rel
ld.Addaddrplus(ctxt, rel, got, got.Size-4)
ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_386_JMP_SLOT))
s.Plt = int32(plt.Size - 16)
} else if ld.HEADTYPE == ld.Hdarwin {
// Same laziness as in 6l.
plt := ld.Linklookup(ctxt, ".plt", 0)
addgotsym(ctxt, s)
ld.Adduint32(ctxt, ld.Linklookup(ctxt, ".linkedit.plt", 0), uint32(s.Dynid))
// jmpq *got+size(IP)
s.Plt = int32(plt.Size)
ld.Adduint8(ctxt, plt, 0xff)
ld.Adduint8(ctxt, plt, 0x25)
ld.Addaddrplus(ctxt, plt, ld.Linklookup(ctxt, ".got", 0), int64(s.Got))
} else {
ld.Diag("addpltsym: unsupported binary format")
}
}
func gentext() {
if !ld.DynlinkingGo() {
return
}
addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
if addmoduledata.Type == ld.STEXT {
// we're linking a module containing the runtime -> no need for
// an init function
return
}
addmoduledata.Reachable = true
initfunc := ld.Linklookup(ld.Ctxt, "go.link.addmoduledata", 0)
initfunc.Type = ld.STEXT
initfunc.Local = true
initfunc.Reachable = true
o := func(op ...uint8) {
for _, op1 := range op {
ld.Adduint8(ld.Ctxt, initfunc, op1)
}
}
// 0000000000000000 <local.dso_init>:
// 0: 48 8d 3d 00 00 00 00 lea 0x0(%rip),%rdi # 7 <local.dso_init+0x7>
// 3: R_X86_64_PC32 runtime.firstmoduledata-0x4
o(0x48, 0x8d, 0x3d)
ld.Addpcrelplus(ld.Ctxt, initfunc, ld.Linklookup(ld.Ctxt, "runtime.firstmoduledata", 0), 0)
// 7: e8 00 00 00 00 callq c <local.dso_init+0xc>
// 8: R_X86_64_PLT32 runtime.addmoduledata-0x4
o(0xe8)
Addcall(ld.Ctxt, initfunc, addmoduledata)
// c: c3 retq
o(0xc3)
if ld.Ctxt.Etextp != nil {
ld.Ctxt.Etextp.Next = initfunc
} else {
ld.Ctxt.Textp = initfunc
}
ld.Ctxt.Etextp = initfunc
initarray_entry := ld.Linklookup(ld.Ctxt, "go.link.addmoduledatainit", 0)
initarray_entry.Reachable = true
initarray_entry.Local = true
initarray_entry.Type = ld.SINITARR
ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
func addpltsym(s *ld.LSym) {
if s.Plt >= 0 {
return
}
adddynsym(ld.Ctxt, s)
if ld.Iself {
plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
rela := ld.Linklookup(ld.Ctxt, ".rela.plt", 0)
if plt.Size == 0 {
elfsetupplt()
}
// jmpq *got+size(IP)
ld.Adduint8(ld.Ctxt, plt, 0xff)
ld.Adduint8(ld.Ctxt, plt, 0x25)
ld.Addpcrelplus(ld.Ctxt, plt, got, got.Size)
// add to got: pointer to current pos in plt
ld.Addaddrplus(ld.Ctxt, got, plt, plt.Size)
// pushq $x
ld.Adduint8(ld.Ctxt, plt, 0x68)
ld.Adduint32(ld.Ctxt, plt, uint32((got.Size-24-8)/8))
// jmpq .plt
ld.Adduint8(ld.Ctxt, plt, 0xe9)
ld.Adduint32(ld.Ctxt, plt, uint32(-(plt.Size + 4)))
// rela
ld.Addaddrplus(ld.Ctxt, rela, got, got.Size-8)
ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_X86_64_JMP_SLOT))
ld.Adduint64(ld.Ctxt, rela, 0)
s.Plt = int32(plt.Size - 16)
} else if ld.HEADTYPE == ld.Hdarwin {
// To do lazy symbol lookup right, we're supposed
// to tell the dynamic loader which library each
// symbol comes from and format the link info
// section just so. I'm too lazy (ha!) to do that
// so for now we'll just use non-lazy pointers,
// which don't need to be told which library to use.
//
// http://networkpx.blogspot.com/2009/09/about-lcdyldinfoonly-command.html
// has details about what we're avoiding.
addgotsym(s)
plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
ld.Adduint32(ld.Ctxt, ld.Linklookup(ld.Ctxt, ".linkedit.plt", 0), uint32(s.Dynid))
// jmpq *got+size(IP)
s.Plt = int32(plt.Size)
ld.Adduint8(ld.Ctxt, plt, 0xff)
ld.Adduint8(ld.Ctxt, plt, 0x25)
ld.Addpcrelplus(ld.Ctxt, plt, ld.Linklookup(ld.Ctxt, ".got", 0), int64(s.Got))
} else {
ld.Diag("addpltsym: unsupported binary format")
}
}
func archinit() {
// getgoextlinkenabled is based on GO_EXTLINK_ENABLED when
// Go was built; see ../../make.bash.
if ld.Linkmode == ld.LinkAuto && obj.Getgoextlinkenabled() == "0" {
ld.Linkmode = ld.LinkInternal
}
switch ld.HEADTYPE {
default:
if ld.Linkmode == ld.LinkAuto {
ld.Linkmode = ld.LinkInternal
}
if ld.Linkmode == ld.LinkExternal && obj.Getgoextlinkenabled() != "1" {
log.Fatalf("cannot use -linkmode=external with -H %s", ld.Headstr(int(ld.HEADTYPE)))
}
case ld.Hlinux,
ld.Hfreebsd,
ld.Hnacl,
ld.Hdarwin:
break
}
switch ld.HEADTYPE {
default:
ld.Diag("unknown -H option")
ld.Errorexit()
fallthrough
case ld.Hplan9: /* plan 9 */
ld.HEADR = 32
if ld.INITTEXT == -1 {
ld.INITTEXT = 4128
}
if ld.INITDAT == -1 {
ld.INITDAT = 0
}
if ld.INITRND == -1 {
ld.INITRND = 4096
}
case ld.Hlinux, /* arm elf */
ld.Hfreebsd,
ld.Hnetbsd,
ld.Hopenbsd:
ld.Debug['d'] = 0
// with dynamic linking
ld.Elfinit()
ld.HEADR = ld.ELFRESERVE
if ld.INITTEXT == -1 {
ld.INITTEXT = 0x10000 + int64(ld.HEADR)
}
if ld.INITDAT == -1 {
ld.INITDAT = 0
}
if ld.INITRND == -1 {
ld.INITRND = 4096
}
case ld.Hnacl:
ld.Elfinit()
ld.HEADR = 0x10000
ld.Funcalign = 16
if ld.INITTEXT == -1 {
ld.INITTEXT = 0x20000
}
if ld.INITDAT == -1 {
ld.INITDAT = 0
}
if ld.INITRND == -1 {
ld.INITRND = 0x10000
}
case ld.Hdarwin: /* apple MACH */
ld.Debug['w'] = 1 // disable DWARF generataion
ld.Machoinit()
ld.HEADR = ld.INITIAL_MACHO_HEADR
if ld.INITTEXT == -1 {
ld.INITTEXT = 4096 + int64(ld.HEADR)
}
if ld.INITDAT == -1 {
ld.INITDAT = 0
}
if ld.INITRND == -1 {
ld.INITRND = 4096
}
}
if ld.INITDAT != 0 && ld.INITRND != 0 {
fmt.Printf("warning: -D0x%x is ignored because of -R0x%x\n", uint64(ld.INITDAT), uint32(ld.INITRND))
}
// embed goarm to runtime.goarm
s := ld.Linklookup(ld.Ctxt, "runtime.goarm", 0)
s.Type = ld.SRODATA
ld.Adduint8(ld.Ctxt, s, uint8(ld.Ctxt.Goarm))
}