// Generate the glink resolver stub if necessary and return the .glink section
func ensureglinkresolver() *ld.LSym {
glink := ld.Linklookup(ld.Ctxt, ".glink", 0)
if glink.Size != 0 {
return glink
}
// This is essentially the resolver from the ppc64 ELF ABI.
// At entry, r12 holds the address of the symbol resolver stub
// for the target routine and the argument registers hold the
// arguments for the target routine.
//
// This stub is PIC, so first get the PC of label 1 into r11.
// Other things will be relative to this.
ld.Adduint32(ld.Ctxt, glink, 0x7c0802a6) // mflr r0
ld.Adduint32(ld.Ctxt, glink, 0x429f0005) // bcl 20,31,1f
ld.Adduint32(ld.Ctxt, glink, 0x7d6802a6) // 1: mflr r11
ld.Adduint32(ld.Ctxt, glink, 0x7c0803a6) // mtlf r0
// Compute the .plt array index from the entry point address.
// Because this is PIC, everything is relative to label 1b (in
// r11):
// r0 = ((r12 - r11) - (res_0 - r11)) / 4 = (r12 - res_0) / 4
ld.Adduint32(ld.Ctxt, glink, 0x3800ffd0) // li r0,-(res_0-1b)=-48
ld.Adduint32(ld.Ctxt, glink, 0x7c006214) // add r0,r0,r12
ld.Adduint32(ld.Ctxt, glink, 0x7c0b0050) // sub r0,r0,r11
ld.Adduint32(ld.Ctxt, glink, 0x7800f082) // srdi r0,r0,2
// r11 = address of the first byte of the PLT
r := ld.Addrel(glink)
r.Off = int32(glink.Size)
r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
r.Siz = 8
r.Type = obj.R_ADDRPOWER
// addis r11,0,.plt@ha; addi r11,r11,.plt@l
r.Add = 0x3d600000<<32 | 0x396b0000
glink.Size += 8
// Load r12 = dynamic resolver address and r11 = DSO
// identifier from the first two doublewords of the PLT.
ld.Adduint32(ld.Ctxt, glink, 0xe98b0000) // ld r12,0(r11)
ld.Adduint32(ld.Ctxt, glink, 0xe96b0008) // ld r11,8(r11)
// Jump to the dynamic resolver
ld.Adduint32(ld.Ctxt, glink, 0x7d8903a6) // mtctr r12
ld.Adduint32(ld.Ctxt, glink, 0x4e800420) // bctr
// The symbol resolvers must immediately follow.
// res_0:
// Add DT_PPC64_GLINK .dynamic entry, which points to 32 bytes
// before the first symbol resolver stub.
s := ld.Linklookup(ld.Ctxt, ".dynamic", 0)
ld.Elfwritedynentsymplus(s, ld.DT_PPC64_GLINK, glink, glink.Size-32)
return glink
}
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 elfsetupplt(ctxt *ld.Link) {
plt := ld.Linklookup(ctxt, ".plt", 0)
got := ld.Linklookup(ctxt, ".got.plt", 0)
if plt.Size == 0 {
// str lr, [sp, #-4]!
ld.Adduint32(ctxt, plt, 0xe52de004)
// ldr lr, [pc, #4]
ld.Adduint32(ctxt, plt, 0xe59fe004)
// add lr, pc, lr
ld.Adduint32(ctxt, plt, 0xe08fe00e)
// ldr pc, [lr, #8]!
ld.Adduint32(ctxt, plt, 0xe5bef008)
// .word &GLOBAL_OFFSET_TABLE[0] - .
ld.Addpcrelplus(ctxt, plt, got, 4)
// the first .plt entry requires 3 .plt.got entries
ld.Adduint32(ctxt, got, 0)
ld.Adduint32(ctxt, got, 0)
ld.Adduint32(ctxt, got, 0)
}
}
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 genaddmoduledata() {
addmoduledata := ld.Linkrlookup(ld.Ctxt, "runtime.addmoduledata", 0)
if addmoduledata.Type == obj.STEXT {
return
}
addmoduledata.Attr |= ld.AttrReachable
initfunc := ld.Linklookup(ld.Ctxt, "go.link.addmoduledata", 0)
initfunc.Type = obj.STEXT
initfunc.Attr |= ld.AttrLocal
initfunc.Attr |= ld.AttrReachable
o := func(op uint32) {
ld.Adduint32(ld.Ctxt, initfunc, op)
}
// addis r2, r12, .TOC.-func@ha
rel := ld.Addrel(initfunc)
rel.Off = int32(initfunc.Size)
rel.Siz = 8
rel.Sym = ld.Linklookup(ld.Ctxt, ".TOC.", 0)
rel.Type = obj.R_ADDRPOWER_PCREL
o(0x3c4c0000)
// addi r2, r2, .TOC.-func@l
o(0x38420000)
// mflr r31
o(0x7c0802a6)
// stdu r31, -32(r1)
o(0xf801ffe1)
// addis r3, r2, local.moduledata@got@ha
rel = ld.Addrel(initfunc)
rel.Off = int32(initfunc.Size)
rel.Siz = 8
rel.Sym = ld.Linklookup(ld.Ctxt, "local.moduledata", 0)
rel.Type = obj.R_ADDRPOWER_GOT
o(0x3c620000)
// ld r3, local.moduledata@got@l(r3)
o(0xe8630000)
// bl runtime.addmoduledata
rel = ld.Addrel(initfunc)
rel.Off = int32(initfunc.Size)
rel.Siz = 4
rel.Sym = addmoduledata
rel.Type = obj.R_CALLPOWER
o(0x48000001)
// nop
o(0x60000000)
// ld r31, 0(r1)
o(0xe8010000)
// mtlr r31
o(0x7c0803a6)
// addi r1,r1,32
o(0x38210020)
// blr
o(0x4e800020)
ld.Ctxt.Textp = append(ld.Ctxt.Textp, initfunc)
initarray_entry := ld.Linklookup(ld.Ctxt, "go.link.addmoduledatainit", 0)
initarray_entry.Attr |= ld.AttrReachable
initarray_entry.Attr |= ld.AttrLocal
initarray_entry.Type = obj.SINITARR
ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
func gentext() {
if !ld.DynlinkingGo() {
return
}
addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
if addmoduledata.Type == obj.STEXT {
// we're linking a module containing the runtime -> no need for
// an init function
return
}
addmoduledata.Attr |= ld.AttrReachable
initfunc := ld.Linklookup(ld.Ctxt, "go.link.addmoduledata", 0)
initfunc.Type = obj.STEXT
initfunc.Attr |= ld.AttrLocal
initfunc.Attr |= ld.AttrReachable
o := func(op uint32) {
ld.Adduint32(ld.Ctxt, initfunc, op)
}
// 0000000000000000 <local.dso_init>:
// 0: 90000000 adrp x0, 0 <runtime.firstmoduledata>
// 0: R_AARCH64_ADR_PREL_PG_HI21 local.moduledata
// 4: 91000000 add x0, x0, #0x0
// 4: R_AARCH64_ADD_ABS_LO12_NC local.moduledata
o(0x90000000)
o(0x91000000)
rel := ld.Addrel(initfunc)
rel.Off = 0
rel.Siz = 8
rel.Sym = ld.Ctxt.Moduledata
rel.Type = obj.R_ADDRARM64
// 8: 14000000 bl 0 <runtime.addmoduledata>
// 8: R_AARCH64_CALL26 runtime.addmoduledata
o(0x14000000)
rel = ld.Addrel(initfunc)
rel.Off = 8
rel.Siz = 4
rel.Sym = ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
rel.Type = obj.R_CALLARM64 // Really should be R_AARCH64_JUMP26 but doesn't seem to make any difference
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.Attr |= ld.AttrReachable
initarray_entry.Attr |= ld.AttrLocal
initarray_entry.Type = obj.SINITARR
ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
// gentext generates assembly to append the local moduledata to the global
// moduledata linked list at initialization time. This is only done if the runtime
// is in a different module.
//
// <go.link.addmoduledata>:
// larl %r2, <local.moduledata>
// jg <runtime.addmoduledata@plt>
// undef
//
// The job of appending the moduledata is delegated to runtime.addmoduledata.
func gentext(ctxt *ld.Link) {
if !ld.DynlinkingGo() {
return
}
addmoduledata := ld.Linklookup(ctxt, "runtime.addmoduledata", 0)
if addmoduledata.Type == obj.STEXT {
// we're linking a module containing the runtime -> no need for
// an init function
return
}
addmoduledata.Attr |= ld.AttrReachable
initfunc := ld.Linklookup(ctxt, "go.link.addmoduledata", 0)
initfunc.Type = obj.STEXT
initfunc.Attr |= ld.AttrLocal
initfunc.Attr |= ld.AttrReachable
// larl %r2, <local.moduledata>
ld.Adduint8(ctxt, initfunc, 0xc0)
ld.Adduint8(ctxt, initfunc, 0x20)
lmd := ld.Addrel(initfunc)
lmd.Off = int32(initfunc.Size)
lmd.Siz = 4
lmd.Sym = ctxt.Moduledata
lmd.Type = obj.R_PCREL
lmd.Variant = ld.RV_390_DBL
lmd.Add = 2 + int64(lmd.Siz)
ld.Adduint32(ctxt, initfunc, 0)
// jg <runtime.addmoduledata[@plt]>
ld.Adduint8(ctxt, initfunc, 0xc0)
ld.Adduint8(ctxt, initfunc, 0xf4)
rel := ld.Addrel(initfunc)
rel.Off = int32(initfunc.Size)
rel.Siz = 4
rel.Sym = ld.Linklookup(ctxt, "runtime.addmoduledata", 0)
rel.Type = obj.R_CALL
rel.Variant = ld.RV_390_DBL
rel.Add = 2 + int64(rel.Siz)
ld.Adduint32(ctxt, initfunc, 0)
// undef (for debugging)
ld.Adduint32(ctxt, initfunc, 0)
ctxt.Textp = append(ctxt.Textp, initfunc)
initarray_entry := ld.Linklookup(ctxt, "go.link.addmoduledatainit", 0)
initarray_entry.Attr |= ld.AttrLocal
initarray_entry.Attr |= ld.AttrReachable
initarray_entry.Type = obj.SINITARR
ld.Addaddr(ctxt, initarray_entry, initfunc)
}
func elfsetupplt(ctxt *ld.Link) {
plt := ld.Linklookup(ctxt, ".plt", 0)
got := ld.Linklookup(ctxt, ".got", 0)
if plt.Size == 0 {
// stg %r1,56(%r15)
ld.Adduint8(ctxt, plt, 0xe3)
ld.Adduint8(ctxt, plt, 0x10)
ld.Adduint8(ctxt, plt, 0xf0)
ld.Adduint8(ctxt, plt, 0x38)
ld.Adduint8(ctxt, plt, 0x00)
ld.Adduint8(ctxt, plt, 0x24)
// larl %r1,_GLOBAL_OFFSET_TABLE_
ld.Adduint8(ctxt, plt, 0xc0)
ld.Adduint8(ctxt, plt, 0x10)
ld.Addpcrelplus(ctxt, plt, got, 6)
// mvc 48(8,%r15),8(%r1)
ld.Adduint8(ctxt, plt, 0xd2)
ld.Adduint8(ctxt, plt, 0x07)
ld.Adduint8(ctxt, plt, 0xf0)
ld.Adduint8(ctxt, plt, 0x30)
ld.Adduint8(ctxt, plt, 0x10)
ld.Adduint8(ctxt, plt, 0x08)
// lg %r1,16(%r1)
ld.Adduint8(ctxt, plt, 0xe3)
ld.Adduint8(ctxt, plt, 0x10)
ld.Adduint8(ctxt, plt, 0x10)
ld.Adduint8(ctxt, plt, 0x10)
ld.Adduint8(ctxt, plt, 0x00)
ld.Adduint8(ctxt, plt, 0x04)
// br %r1
ld.Adduint8(ctxt, plt, 0x07)
ld.Adduint8(ctxt, plt, 0xf1)
// nopr %r0
ld.Adduint8(ctxt, plt, 0x07)
ld.Adduint8(ctxt, plt, 0x00)
// nopr %r0
ld.Adduint8(ctxt, plt, 0x07)
ld.Adduint8(ctxt, plt, 0x00)
// nopr %r0
ld.Adduint8(ctxt, plt, 0x07)
ld.Adduint8(ctxt, plt, 0x00)
// assume got->size == 0 too
ld.Addaddrplus(ctxt, got, ld.Linklookup(ctxt, ".dynamic", 0), 0)
ld.Adduint64(ctxt, got, 0)
ld.Adduint64(ctxt, got, 0)
}
}
func gentext() {
if !ld.DynlinkingGo() {
return
}
addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
if addmoduledata.Type == obj.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 = obj.STEXT
initfunc.Local = true
initfunc.Reachable = true
o := func(op uint32) {
ld.Adduint32(ld.Ctxt, initfunc, op)
}
o(0xe59f0004)
o(0xe08f0000)
o(0xeafffffe)
rel := ld.Addrel(initfunc)
rel.Off = 8
rel.Siz = 4
rel.Sym = ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
rel.Type = obj.R_CALLARM
rel.Add = 0xeafffffe // vomit
o(0x00000000)
rel = ld.Addrel(initfunc)
rel.Off = 12
rel.Siz = 4
rel.Sym = ld.Ctxt.Moduledata
rel.Type = obj.R_PCREL
rel.Add = 4
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 = obj.SINITARR
ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
func gentext() {
if !ld.DynlinkingGo() && ld.Buildmode != ld.BuildmodePIE {
return
}
thunkfunc := ld.Linklookup(ld.Ctxt, "__x86.get_pc_thunk.cx", 0)
thunkfunc.Type = obj.STEXT
thunkfunc.Local = true
thunkfunc.Reachable = true
o := func(op ...uint8) {
for _, op1 := range op {
ld.Adduint8(ld.Ctxt, thunkfunc, op1)
}
}
// 8b 0c 24 mov (%esp),%ecx
o(0x8b, 0x0c, 0x24)
// c3 ret
o(0xc3)
if ld.Ctxt.Etextp != nil {
ld.Ctxt.Etextp.Next = thunkfunc
} else {
ld.Ctxt.Textp = thunkfunc
}
ld.Ctxt.Etextp = thunkfunc
}
func addgotsym(ctxt *ld.Link, s *ld.Symbol) {
if s.Got >= 0 {
return
}
ld.Adddynsym(ctxt, s)
got := ld.Linklookup(ctxt, ".got", 0)
s.Got = int32(got.Size)
ld.Adduint32(ctxt, got, 0)
if ld.Iself {
rel := ld.Linklookup(ctxt, ".rel", 0)
ld.Addaddrplus(ctxt, rel, got, int64(s.Got))
ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_ARM_GLOB_DAT))
} else {
ctxt.Diag("addgotsym: unsupported binary format")
}
}
func gentext(ctxt *ld.Link) {
if !ld.DynlinkingGo() {
return
}
addmoduledata := ld.Linklookup(ctxt, "runtime.addmoduledata", 0)
if addmoduledata.Type == obj.STEXT {
// we're linking a module containing the runtime -> no need for
// an init function
return
}
addmoduledata.Attr |= ld.AttrReachable
initfunc := ld.Linklookup(ctxt, "go.link.addmoduledata", 0)
initfunc.Type = obj.STEXT
initfunc.Attr |= ld.AttrLocal
initfunc.Attr |= ld.AttrReachable
o := func(op uint32) {
ld.Adduint32(ctxt, initfunc, op)
}
o(0xe59f0004)
o(0xe08f0000)
o(0xeafffffe)
rel := ld.Addrel(initfunc)
rel.Off = 8
rel.Siz = 4
rel.Sym = ld.Linklookup(ctxt, "runtime.addmoduledata", 0)
rel.Type = obj.R_CALLARM
rel.Add = 0xeafffffe // vomit
o(0x00000000)
rel = ld.Addrel(initfunc)
rel.Off = 12
rel.Siz = 4
rel.Sym = ctxt.Moduledata
rel.Type = obj.R_PCREL
rel.Add = 4
ctxt.Textp = append(ctxt.Textp, initfunc)
initarray_entry := ld.Linklookup(ctxt, "go.link.addmoduledatainit", 0)
initarray_entry.Attr |= ld.AttrReachable
initarray_entry.Attr |= ld.AttrLocal
initarray_entry.Type = obj.SINITARR
ld.Addaddr(ctxt, initarray_entry, initfunc)
}
func addpltsym(ctxt *ld.Link, s *ld.Symbol) {
if s.Plt >= 0 {
return
}
ld.Adddynsym(ctxt, s)
if ld.Iself {
plt := ld.Linklookup(ctxt, ".plt", 0)
rela := ld.Linklookup(ctxt, ".rela.plt", 0)
if plt.Size == 0 {
elfsetupplt()
}
// Create the glink resolver if necessary
glink := ensureglinkresolver()
// Write symbol resolver stub (just a branch to the
// glink resolver stub)
r := ld.Addrel(glink)
r.Sym = glink
r.Off = int32(glink.Size)
r.Siz = 4
r.Type = obj.R_CALLPOWER
ld.Adduint32(ctxt, glink, 0x48000000) // b .glink
// In the ppc64 ABI, the dynamic linker is responsible
// for writing the entire PLT. We just need to
// reserve 8 bytes for each PLT entry and generate a
// JMP_SLOT dynamic relocation for it.
//
// TODO(austin): ABI v1 is different
s.Plt = int32(plt.Size)
plt.Size += 8
ld.Addaddrplus(ctxt, rela, plt, int64(s.Plt))
ld.Adduint64(ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_PPC64_JMP_SLOT))
ld.Adduint64(ctxt, rela, 0)
} else {
ld.Diag("addpltsym: unsupported binary format")
}
}
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
if ld.Linkmode == ld.LinkExternal {
// TODO(minux): translate R_ADDRPOWER and R_CALLPOWER into standard ELF relocations.
// R_ADDRPOWER corresponds to R_PPC_ADDR16_HA and R_PPC_ADDR16_LO.
// R_CALLPOWER corresponds to R_PPC_REL24.
return -1
}
switch r.Type {
case obj.R_CONST:
*val = r.Add
return 0
case obj.R_GOTOFF:
*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ld.Linklookup(ld.Ctxt, ".got", 0))
return 0
case obj.R_ADDRPOWER, obj.R_ADDRPOWER_DS:
return archrelocaddr(r, s, val)
case obj.R_CALLPOWER:
// Bits 6 through 29 = (S + A - P) >> 2
t := ld.Symaddr(r.Sym) + r.Add - (s.Value + int64(r.Off))
if t&3 != 0 {
ld.Ctxt.Diag("relocation for %s+%d is not aligned: %d", r.Sym.Name, r.Off, t)
}
if int64(int32(t<<6)>>6) != t {
// TODO(austin) This can happen if text > 32M.
// Add a call trampoline to .text in that case.
ld.Ctxt.Diag("relocation for %s+%d is too big: %d", r.Sym.Name, r.Off, t)
}
*val |= int64(uint32(t) &^ 0xfc000003)
return 0
case obj.R_POWER_TOC: // S + A - .TOC.
*val = ld.Symaddr(r.Sym) + r.Add - symtoc(s)
return 0
case obj.R_POWER_TLS_LE:
// The thread pointer points 0x7000 bytes after the start of the the
// thread local storage area as documented in section "3.7.2 TLS
// Runtime Handling" of "Power Architecture 64-Bit ELF V2 ABI
// Specification".
v := r.Sym.Value - 0x7000
if int64(int16(v)) != v {
ld.Diag("TLS offset out of range %d", v)
}
*val = (*val &^ 0xffff) | (v & 0xffff)
return 0
}
return -1
}
func addgotsym(s *ld.Symbol) {
if s.Got >= 0 {
return
}
ld.Adddynsym(ld.Ctxt, s)
got := ld.Linklookup(ld.Ctxt, ".got", 0)
s.Got = int32(got.Size)
ld.Adduint64(ld.Ctxt, got, 0)
if ld.Iself {
rela := ld.Linklookup(ld.Ctxt, ".rela", 0)
ld.Addaddrplus(ld.Ctxt, rela, got, int64(s.Got))
ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(s.Dynid), ld.R_390_GLOB_DAT))
ld.Adduint64(ld.Ctxt, rela, 0)
} else {
ld.Diag("addgotsym: unsupported binary format")
}
}
func gentext() {
if !ld.DynlinkingGo() {
return
}
addmoduledata := ld.Linklookup(ld.Ctxt, "runtime.addmoduledata", 0)
if addmoduledata.Type == obj.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 = obj.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.Ctxt.Moduledata, 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 = obj.SINITARR
ld.Addaddr(ld.Ctxt, initarray_entry, initfunc)
}
func elfsetupplt() {
plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
if plt.Size == 0 {
// The dynamic linker stores the address of the
// dynamic resolver and the DSO identifier in the two
// doublewords at the beginning of the .plt section
// before the PLT array. Reserve space for these.
plt.Size = 16
}
}
func addgotsym(ctxt *ld.Link, s *ld.LSym) {
if s.Got >= 0 {
return
}
ld.Adddynsym(ctxt, s)
got := ld.Linklookup(ctxt, ".got", 0)
s.Got = int32(got.Size)
ld.Adduint32(ctxt, got, 0)
if ld.Iself {
rel := ld.Linklookup(ctxt, ".rel", 0)
ld.Addaddrplus(ctxt, rel, got, int64(s.Got))
ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_386_GLOB_DAT))
} else if ld.HEADTYPE == obj.Hdarwin {
ld.Adduint32(ctxt, ld.Linklookup(ctxt, ".linkedit.got", 0), uint32(s.Dynid))
} else {
ld.Diag("addgotsym: unsupported binary format")
}
}
func addpltsym(ctxt *ld.Link, s *ld.LSym) {
if s.Plt >= 0 {
return
}
ld.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 == obj.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 addpltsym(ctxt *ld.Link, s *ld.Symbol) {
if s.Plt >= 0 {
return
}
ld.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(ctxt)
}
// .got entry
s.Got = int32(got.Size)
// In theory, all GOT should point to the first PLT entry,
// Linux/ARM's dynamic linker will do that for us, but FreeBSD/ARM's
// dynamic linker won't, so we'd better do it ourselves.
ld.Addaddrplus(ctxt, got, plt, 0)
// .plt entry, this depends on the .got entry
s.Plt = int32(plt.Size)
addpltreloc(ctxt, plt, got, s, obj.R_PLT0) // add lr, pc, #0xXX00000
addpltreloc(ctxt, plt, got, s, obj.R_PLT1) // add lr, lr, #0xYY000
addpltreloc(ctxt, plt, got, s, obj.R_PLT2) // ldr pc, [lr, #0xZZZ]!
// rel
ld.Addaddrplus(ctxt, rel, got, int64(s.Got))
ld.Adduint32(ctxt, rel, ld.ELF32_R_INFO(uint32(s.Dynid), ld.R_ARM_JUMP_SLOT))
} else {
ctxt.Diag("addpltsym: unsupported binary format")
}
}
func addgotsyminternal(ctxt *ld.Link, s *ld.Symbol) {
if s.Got >= 0 {
return
}
got := ld.Linklookup(ctxt, ".got", 0)
s.Got = int32(got.Size)
ld.Addaddrplus(ctxt, got, s, 0)
if ld.Iself {
} else {
ctxt.Diag("addgotsyminternal: unsupported binary format")
}
}
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
if ld.Linkmode == ld.LinkExternal {
return -1
}
switch r.Type {
case obj.R_CONST:
*val = r.Add
return 0
case obj.R_GOTOFF:
*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ld.Linklookup(ld.Ctxt, ".got", 0))
return 0
}
return -1
}
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
if ld.Linkmode == ld.LinkExternal {
return -1
}
switch r.Type {
case obj.R_CONST:
*val = r.Add
return 0
case obj.R_GOTOFF:
*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ld.Linklookup(ld.Ctxt, ".got", 0))
return 0
case obj.R_ADDRMIPS:
t := ld.Symaddr(r.Sym) + r.Add
if t >= 1<<32 || t < -1<<32 {
ld.Diag("program too large, address relocation = %v", t)
}
// the first instruction is always at the lower address, this is endian neutral;
// but note that o1 and o2 should still use the target endian.
o1 := ld.Thelinkarch.ByteOrder.Uint32(s.P[r.Off:])
o2 := ld.Thelinkarch.ByteOrder.Uint32(s.P[r.Off+4:])
o1 = o1&0xffff0000 | uint32(t>>16)&0xffff
o2 = o2&0xffff0000 | uint32(t)&0xffff
// when laid out, the instruction order must always be o1, o2.
if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
*val = int64(o1)<<32 | int64(o2)
} else {
*val = int64(o2)<<32 | int64(o1)
}
return 0
case obj.R_CALLMIPS,
obj.R_JMPMIPS:
// Low 26 bits = (S + A) >> 2
t := ld.Symaddr(r.Sym) + r.Add
o1 := ld.Thelinkarch.ByteOrder.Uint32(s.P[r.Off:])
*val = int64(o1&0xfc000000 | uint32(t>>2)&^0xfc000000)
return 0
}
return -1
}
// Construct a call stub in stub that calls symbol targ via its PLT
// entry.
func gencallstub(abicase int, stub *ld.Symbol, targ *ld.Symbol) {
if abicase != 1 {
// If we see R_PPC64_TOCSAVE or R_PPC64_REL24_NOTOC
// relocations, we'll need to implement cases 2 and 3.
log.Fatalf("gencallstub only implements case 1 calls")
}
plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
stub.Type = obj.STEXT
// Save TOC pointer in TOC save slot
ld.Adduint32(ld.Ctxt, stub, 0xf8410018) // std r2,24(r1)
// Load the function pointer from the PLT.
r := ld.Addrel(stub)
r.Off = int32(stub.Size)
r.Sym = plt
r.Add = int64(targ.Plt)
r.Siz = 2
if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
r.Off += int32(r.Siz)
}
r.Type = obj.R_POWER_TOC
r.Variant = ld.RV_POWER_HA
ld.Adduint32(ld.Ctxt, stub, 0x3d820000) // addis r12,r2,targ@plt@toc@ha
r = ld.Addrel(stub)
r.Off = int32(stub.Size)
r.Sym = plt
r.Add = int64(targ.Plt)
r.Siz = 2
if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
r.Off += int32(r.Siz)
}
r.Type = obj.R_POWER_TOC
r.Variant = ld.RV_POWER_LO
ld.Adduint32(ld.Ctxt, stub, 0xe98c0000) // ld r12,targ@plt@toc@l(r12)
// Jump to the loaded pointer
ld.Adduint32(ld.Ctxt, stub, 0x7d8903a6) // mtctr r12
ld.Adduint32(ld.Ctxt, stub, 0x4e800420) // bctr
}
func adddynrel(s *ld.LSym, r *ld.Reloc) {
targ := r.Sym
ld.Ctxt.Cursym = s
switch r.Type {
default:
if r.Type >= 256 {
ld.Diag("unexpected relocation type %d", r.Type)
return
}
// Handle relocations found in ELF object files.
case 256 + ld.R_386_PC32:
if targ.Type == obj.SDYNIMPORT {
ld.Diag("unexpected R_386_PC32 relocation for dynamic symbol %s", targ.Name)
}
if targ.Type == 0 || targ.Type == obj.SXREF {
ld.Diag("unknown symbol %s in pcrel", targ.Name)
}
r.Type = obj.R_PCREL
r.Add += 4
return
case 256 + ld.R_386_PLT32:
r.Type = obj.R_PCREL
r.Add += 4
if targ.Type == obj.SDYNIMPORT {
addpltsym(ld.Ctxt, targ)
r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
r.Add += int64(targ.Plt)
}
return
case 256 + ld.R_386_GOT32, 256 + ld.R_386_GOT32X:
if targ.Type != obj.SDYNIMPORT {
// have symbol
if r.Off >= 2 && s.P[r.Off-2] == 0x8b {
// turn MOVL of GOT entry into LEAL of symbol address, relative to GOT.
s.P[r.Off-2] = 0x8d
r.Type = obj.R_GOTOFF
return
}
if r.Off >= 2 && s.P[r.Off-2] == 0xff && s.P[r.Off-1] == 0xb3 {
// turn PUSHL of GOT entry into PUSHL of symbol itself.
// use unnecessary SS prefix to keep instruction same length.
s.P[r.Off-2] = 0x36
s.P[r.Off-1] = 0x68
r.Type = obj.R_ADDR
return
}
ld.Diag("unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
return
}
addgotsym(ld.Ctxt, targ)
r.Type = obj.R_CONST // write r->add during relocsym
r.Sym = nil
r.Add += int64(targ.Got)
return
case 256 + ld.R_386_GOTOFF:
r.Type = obj.R_GOTOFF
return
case 256 + ld.R_386_GOTPC:
r.Type = obj.R_PCREL
r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
r.Add += 4
return
case 256 + ld.R_386_32:
if targ.Type == obj.SDYNIMPORT {
ld.Diag("unexpected R_386_32 relocation for dynamic symbol %s", targ.Name)
}
r.Type = obj.R_ADDR
return
case 512 + ld.MACHO_GENERIC_RELOC_VANILLA*2 + 0:
r.Type = obj.R_ADDR
if targ.Type == obj.SDYNIMPORT {
ld.Diag("unexpected reloc for dynamic symbol %s", targ.Name)
}
return
case 512 + ld.MACHO_GENERIC_RELOC_VANILLA*2 + 1:
if targ.Type == obj.SDYNIMPORT {
addpltsym(ld.Ctxt, targ)
r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
r.Add = int64(targ.Plt)
r.Type = obj.R_PCREL
return
}
r.Type = obj.R_PCREL
return
case 512 + ld.MACHO_FAKE_GOTPCREL:
if targ.Type != obj.SDYNIMPORT {
// have symbol
// turn MOVL of GOT entry into LEAL of symbol itself
if r.Off < 2 || s.P[r.Off-2] != 0x8b {
ld.Diag("unexpected GOT reloc for non-dynamic symbol %s", targ.Name)
return
}
s.P[r.Off-2] = 0x8d
r.Type = obj.R_PCREL
return
}
addgotsym(ld.Ctxt, targ)
r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
r.Add += int64(targ.Got)
r.Type = obj.R_PCREL
return
}
// Handle references to ELF symbols from our own object files.
if targ.Type != obj.SDYNIMPORT {
return
}
switch r.Type {
case obj.R_CALL,
obj.R_PCREL:
addpltsym(ld.Ctxt, targ)
r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
r.Add = int64(targ.Plt)
return
case obj.R_ADDR:
if s.Type != obj.SDATA {
break
}
if ld.Iself {
ld.Adddynsym(ld.Ctxt, targ)
rel := ld.Linklookup(ld.Ctxt, ".rel", 0)
ld.Addaddrplus(ld.Ctxt, rel, s, int64(r.Off))
ld.Adduint32(ld.Ctxt, rel, ld.ELF32_R_INFO(uint32(targ.Dynid), ld.R_386_32))
r.Type = obj.R_CONST // write r->add during relocsym
r.Sym = nil
return
}
if ld.HEADTYPE == obj.Hdarwin && s.Size == PtrSize && r.Off == 0 {
// Mach-O relocations are a royal pain to lay out.
// They use a compact stateful bytecode representation
// that is too much bother to deal with.
// Instead, interpret the C declaration
// void *_Cvar_stderr = &stderr;
// as making _Cvar_stderr the name of a GOT entry
// for stderr. This is separate from the usual GOT entry,
// just in case the C code assigns to the variable,
// and of course it only works for single pointers,
// but we only need to support cgo and that's all it needs.
ld.Adddynsym(ld.Ctxt, targ)
got := ld.Linklookup(ld.Ctxt, ".got", 0)
s.Type = got.Type | obj.SSUB
s.Outer = got
s.Sub = got.Sub
got.Sub = s
s.Value = got.Size
ld.Adduint32(ld.Ctxt, got, 0)
ld.Adduint32(ld.Ctxt, ld.Linklookup(ld.Ctxt, ".linkedit.got", 0), uint32(targ.Dynid))
r.Type = 256 // ignore during relocsym
return
}
if ld.HEADTYPE == obj.Hwindows && s.Size == PtrSize {
// nothing to do, the relocation will be laid out in pereloc1
return
}
}
ld.Ctxt.Cursym = s
ld.Diag("unsupported relocation for dynamic symbol %s (type=%d stype=%d)", targ.Name, r.Type, targ.Type)
}
func asmb() {
if ld.Debug['v'] != 0 {
fmt.Fprintf(&ld.Bso, "%5.2f asmb\n", obj.Cputime())
}
ld.Bso.Flush()
if ld.Iself {
ld.Asmbelfsetup()
}
sect := ld.Segtext.Sect
ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
ld.Codeblk(int64(sect.Vaddr), int64(sect.Length))
for sect = sect.Next; sect != nil; sect = sect.Next {
ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
ld.Datblk(int64(sect.Vaddr), int64(sect.Length))
}
if ld.Segrodata.Filelen > 0 {
if ld.Debug['v'] != 0 {
fmt.Fprintf(&ld.Bso, "%5.2f rodatblk\n", obj.Cputime())
}
ld.Bso.Flush()
ld.Cseek(int64(ld.Segrodata.Fileoff))
ld.Datblk(int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
}
if ld.Debug['v'] != 0 {
fmt.Fprintf(&ld.Bso, "%5.2f datblk\n", obj.Cputime())
}
ld.Bso.Flush()
ld.Cseek(int64(ld.Segdata.Fileoff))
ld.Datblk(int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))
machlink := uint32(0)
if ld.HEADTYPE == obj.Hdarwin {
if ld.Debug['v'] != 0 {
fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
}
dwarfoff := uint32(ld.Rnd(int64(uint64(ld.HEADR)+ld.Segtext.Length), int64(ld.INITRND)) + ld.Rnd(int64(ld.Segdata.Filelen), int64(ld.INITRND)))
ld.Cseek(int64(dwarfoff))
ld.Segdwarf.Fileoff = uint64(ld.Cpos())
ld.Dwarfemitdebugsections()
ld.Segdwarf.Filelen = uint64(ld.Cpos()) - ld.Segdwarf.Fileoff
machlink = uint32(ld.Domacholink())
}
ld.Symsize = 0
ld.Spsize = 0
ld.Lcsize = 0
symo := uint32(0)
if ld.Debug['s'] == 0 {
// TODO: rationalize
if ld.Debug['v'] != 0 {
fmt.Fprintf(&ld.Bso, "%5.2f sym\n", obj.Cputime())
}
ld.Bso.Flush()
switch ld.HEADTYPE {
default:
if ld.Iself {
symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
symo = uint32(ld.Rnd(int64(symo), int64(ld.INITRND)))
}
case obj.Hplan9:
symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
case obj.Hdarwin:
symo = uint32(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(ld.INITRND))) + uint64(machlink))
case obj.Hwindows:
symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
symo = uint32(ld.Rnd(int64(symo), ld.PEFILEALIGN))
}
ld.Cseek(int64(symo))
switch ld.HEADTYPE {
default:
if ld.Iself {
if ld.Debug['v'] != 0 {
fmt.Fprintf(&ld.Bso, "%5.2f elfsym\n", obj.Cputime())
}
ld.Asmelfsym()
ld.Cflush()
ld.Cwrite(ld.Elfstrdat)
if ld.Debug['v'] != 0 {
fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
}
ld.Dwarfemitdebugsections()
if ld.Linkmode == ld.LinkExternal {
ld.Elfemitreloc()
}
}
case obj.Hplan9:
ld.Asmplan9sym()
ld.Cflush()
sym := ld.Linklookup(ld.Ctxt, "pclntab", 0)
if sym != nil {
ld.Lcsize = int32(len(sym.P))
for i := 0; int32(i) < ld.Lcsize; i++ {
ld.Cput(uint8(sym.P[i]))
}
ld.Cflush()
}
case obj.Hwindows:
if ld.Debug['v'] != 0 {
fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
}
ld.Dwarfemitdebugsections()
case obj.Hdarwin:
if ld.Linkmode == ld.LinkExternal {
ld.Machoemitreloc()
}
}
}
if ld.Debug['v'] != 0 {
fmt.Fprintf(&ld.Bso, "%5.2f headr\n", obj.Cputime())
}
ld.Bso.Flush()
ld.Cseek(0)
switch ld.HEADTYPE {
default:
case obj.Hplan9: /* plan9 */
magic := int32(4*11*11 + 7)
ld.Lputb(uint32(magic)) /* magic */
ld.Lputb(uint32(ld.Segtext.Filelen)) /* sizes */
ld.Lputb(uint32(ld.Segdata.Filelen))
ld.Lputb(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
ld.Lputb(uint32(ld.Symsize)) /* nsyms */
ld.Lputb(uint32(ld.Entryvalue())) /* va of entry */
ld.Lputb(uint32(ld.Spsize)) /* sp offsets */
ld.Lputb(uint32(ld.Lcsize)) /* line offsets */
case obj.Hdarwin:
ld.Asmbmacho()
case obj.Hlinux,
obj.Hfreebsd,
obj.Hnetbsd,
obj.Hopenbsd,
obj.Hnacl:
ld.Asmbelf(int64(symo))
case obj.Hwindows:
ld.Asmbpe()
}
ld.Cflush()
}
func asmb() {
if ld.Debug['v'] != 0 {
fmt.Fprintf(ld.Bso, "%5.2f asmb\n", obj.Cputime())
}
ld.Bso.Flush()
if ld.Iself {
ld.Asmbelfsetup()
}
sect := ld.Segtext.Sect
ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
ld.Codeblk(int64(sect.Vaddr), int64(sect.Length))
for sect = sect.Next; sect != nil; sect = sect.Next {
ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
ld.Datblk(int64(sect.Vaddr), int64(sect.Length))
}
if ld.Segrodata.Filelen > 0 {
if ld.Debug['v'] != 0 {
fmt.Fprintf(ld.Bso, "%5.2f rodatblk\n", obj.Cputime())
}
ld.Bso.Flush()
ld.Cseek(int64(ld.Segrodata.Fileoff))
ld.Datblk(int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
}
if ld.Debug['v'] != 0 {
fmt.Fprintf(ld.Bso, "%5.2f datblk\n", obj.Cputime())
}
ld.Bso.Flush()
ld.Cseek(int64(ld.Segdata.Fileoff))
ld.Datblk(int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))
ld.Cseek(int64(ld.Segdwarf.Fileoff))
ld.Dwarfblk(int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))
/* output symbol table */
ld.Symsize = 0
ld.Lcsize = 0
symo := uint32(0)
if ld.Debug['s'] == 0 {
// TODO: rationalize
if ld.Debug['v'] != 0 {
fmt.Fprintf(ld.Bso, "%5.2f sym\n", obj.Cputime())
}
ld.Bso.Flush()
switch ld.HEADTYPE {
default:
if ld.Iself {
symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
symo = uint32(ld.Rnd(int64(symo), int64(ld.INITRND)))
}
case obj.Hplan9:
symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
}
ld.Cseek(int64(symo))
switch ld.HEADTYPE {
default:
if ld.Iself {
if ld.Debug['v'] != 0 {
fmt.Fprintf(ld.Bso, "%5.2f elfsym\n", obj.Cputime())
}
ld.Asmelfsym()
ld.Cflush()
ld.Cwrite(ld.Elfstrdat)
if ld.Linkmode == ld.LinkExternal {
ld.Elfemitreloc()
}
}
case obj.Hplan9:
ld.Asmplan9sym()
ld.Cflush()
sym := ld.Linklookup(ld.Ctxt, "pclntab", 0)
if sym != nil {
ld.Lcsize = int32(len(sym.P))
for i := 0; int32(i) < ld.Lcsize; i++ {
ld.Cput(sym.P[i])
}
ld.Cflush()
}
}
}
ld.Ctxt.Cursym = nil
if ld.Debug['v'] != 0 {
fmt.Fprintf(ld.Bso, "%5.2f header\n", obj.Cputime())
}
ld.Bso.Flush()
ld.Cseek(0)
switch ld.HEADTYPE {
default:
case obj.Hplan9: /* plan 9 */
ld.Thearch.Lput(0x647) /* magic */
ld.Thearch.Lput(uint32(ld.Segtext.Filelen)) /* sizes */
ld.Thearch.Lput(uint32(ld.Segdata.Filelen))
ld.Thearch.Lput(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
ld.Thearch.Lput(uint32(ld.Symsize)) /* nsyms */
ld.Thearch.Lput(uint32(ld.Entryvalue())) /* va of entry */
ld.Thearch.Lput(0)
ld.Thearch.Lput(uint32(ld.Lcsize))
case obj.Hlinux,
obj.Hfreebsd,
obj.Hnetbsd,
obj.Hopenbsd,
obj.Hnacl:
ld.Asmbelf(int64(symo))
}
ld.Cflush()
if ld.Debug['c'] != 0 {
fmt.Printf("textsize=%d\n", ld.Segtext.Filelen)
fmt.Printf("datsize=%d\n", ld.Segdata.Filelen)
fmt.Printf("bsssize=%d\n", ld.Segdata.Length-ld.Segdata.Filelen)
fmt.Printf("symsize=%d\n", ld.Symsize)
fmt.Printf("lcsize=%d\n", ld.Lcsize)
fmt.Printf("total=%d\n", ld.Segtext.Filelen+ld.Segdata.Length+uint64(ld.Symsize)+uint64(ld.Lcsize))
}
}
func archreloc(r *ld.Reloc, s *ld.Symbol, val *int64) int {
if ld.Linkmode == ld.LinkExternal {
switch r.Type {
default:
return -1
case obj.R_POWER_TLS, obj.R_POWER_TLS_LE, obj.R_POWER_TLS_IE:
r.Done = 0
// check Outer is nil, Type is TLSBSS?
r.Xadd = r.Add
r.Xsym = r.Sym
return 0
case obj.R_ADDRPOWER,
obj.R_ADDRPOWER_DS,
obj.R_ADDRPOWER_TOCREL,
obj.R_ADDRPOWER_TOCREL_DS,
obj.R_ADDRPOWER_GOT,
obj.R_ADDRPOWER_PCREL:
r.Done = 0
// set up addend for eventual relocation via outer symbol.
rs := r.Sym
r.Xadd = r.Add
for rs.Outer != nil {
r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
rs = rs.Outer
}
if rs.Type != obj.SHOSTOBJ && rs.Type != obj.SDYNIMPORT && rs.Sect == nil {
ld.Diag("missing section for %s", rs.Name)
}
r.Xsym = rs
return 0
case obj.R_CALLPOWER:
r.Done = 0
r.Xsym = r.Sym
r.Xadd = r.Add
return 0
}
}
switch r.Type {
case obj.R_CONST:
*val = r.Add
return 0
case obj.R_GOTOFF:
*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ld.Linklookup(ld.Ctxt, ".got", 0))
return 0
case obj.R_ADDRPOWER, obj.R_ADDRPOWER_DS:
return archrelocaddr(r, s, val)
case obj.R_CALLPOWER:
// Bits 6 through 29 = (S + A - P) >> 2
t := ld.Symaddr(r.Sym) + r.Add - (s.Value + int64(r.Off))
if t&3 != 0 {
ld.Ctxt.Diag("relocation for %s+%d is not aligned: %d", r.Sym.Name, r.Off, t)
}
if int64(int32(t<<6)>>6) != t {
// TODO(austin) This can happen if text > 32M.
// Add a call trampoline to .text in that case.
ld.Ctxt.Diag("relocation for %s+%d is too big: %d", r.Sym.Name, r.Off, t)
}
*val |= int64(uint32(t) &^ 0xfc000003)
return 0
case obj.R_POWER_TOC: // S + A - .TOC.
*val = ld.Symaddr(r.Sym) + r.Add - symtoc(s)
return 0
case obj.R_POWER_TLS_LE:
// The thread pointer points 0x7000 bytes after the start of the the
// thread local storage area as documented in section "3.7.2 TLS
// Runtime Handling" of "Power Architecture 64-Bit ELF V2 ABI
// Specification".
v := r.Sym.Value - 0x7000
if int64(int16(v)) != v {
ld.Diag("TLS offset out of range %d", v)
}
*val = (*val &^ 0xffff) | (v & 0xffff)
return 0
}
return -1
}
func genplt() {
// The ppc64 ABI PLT has similar concepts to other
// architectures, but is laid out quite differently. When we
// see an R_PPC64_REL24 relocation to a dynamic symbol
// (indicating that the call needs to go through the PLT), we
// generate up to three stubs and reserve a PLT slot.
//
// 1) The call site will be bl x; nop (where the relocation
// applies to the bl). We rewrite this to bl x_stub; ld
// r2,24(r1). The ld is necessary because x_stub will save
// r2 (the TOC pointer) at 24(r1) (the "TOC save slot").
//
// 2) We reserve space for a pointer in the .plt section (once
// per referenced dynamic function). .plt is a data
// section filled solely by the dynamic linker (more like
// .plt.got on other architectures). Initially, the
// dynamic linker will fill each slot with a pointer to the
// corresponding x@plt entry point.
//
// 3) We generate the "call stub" x_stub (once per dynamic
// function/object file pair). This saves the TOC in the
// TOC save slot, reads the function pointer from x's .plt
// slot and calls it like any other global entry point
// (including setting r12 to the function address).
//
// 4) We generate the "symbol resolver stub" x@plt (once per
// dynamic function). This is solely a branch to the glink
// resolver stub.
//
// 5) We generate the glink resolver stub (only once). This
// computes which symbol resolver stub we came through and
// invokes the dynamic resolver via a pointer provided by
// the dynamic linker. This will patch up the .plt slot to
// point directly at the function so future calls go
// straight from the call stub to the real function, and
// then call the function.
// NOTE: It's possible we could make ppc64 closer to other
// architectures: ppc64's .plt is like .plt.got on other
// platforms and ppc64's .glink is like .plt on other
// platforms.
// Find all R_PPC64_REL24 relocations that reference dynamic
// imports. Reserve PLT entries for these symbols and
// generate call stubs. The call stubs need to live in .text,
// which is why we need to do this pass this early.
//
// This assumes "case 1" from the ABI, where the caller needs
// us to save and restore the TOC pointer.
for _, s := range ld.Ctxt.Textp {
for i := range s.R {
r := &s.R[i]
if r.Type != 256+ld.R_PPC64_REL24 || r.Sym.Type != obj.SDYNIMPORT {
continue
}
// Reserve PLT entry and generate symbol
// resolver
addpltsym(ld.Ctxt, r.Sym)
// Generate call stub
n := fmt.Sprintf("%s.%s", s.Name, r.Sym.Name)
stub := ld.Linklookup(ld.Ctxt, n, 0)
if s.Attr.Reachable() {
stub.Attr |= ld.AttrReachable
}
if stub.Size == 0 {
// Need outer to resolve .TOC.
stub.Outer = s
ld.Ctxt.Textp = append(ld.Ctxt.Textp, stub)
gencallstub(1, stub, r.Sym)
}
// Update the relocation to use the call stub
r.Sym = stub
// Restore TOC after bl. The compiler put a
// nop here for us to overwrite.
const o1 = 0xe8410018 // ld r2,24(r1)
ld.Ctxt.Arch.ByteOrder.PutUint32(s.P[r.Off+4:], o1)
}
}
}
func adddynrel(s *ld.Symbol, r *ld.Reloc) {
targ := r.Sym
ld.Ctxt.Cursym = s
switch r.Type {
default:
if r.Type >= 256 {
ld.Diag("unexpected relocation type %d", r.Type)
return
}
// Handle relocations found in ELF object files.
case 256 + ld.R_PPC64_REL24:
r.Type = obj.R_CALLPOWER
// This is a local call, so the caller isn't setting
// up r12 and r2 is the same for the caller and
// callee. Hence, we need to go to the local entry
// point. (If we don't do this, the callee will try
// to use r12 to compute r2.)
r.Add += int64(r.Sym.Localentry) * 4
if targ.Type == obj.SDYNIMPORT {
// Should have been handled in elfsetupplt
ld.Diag("unexpected R_PPC64_REL24 for dyn import")
}
return
case 256 + ld.R_PPC_REL32:
r.Type = obj.R_PCREL
r.Add += 4
if targ.Type == obj.SDYNIMPORT {
ld.Diag("unexpected R_PPC_REL32 for dyn import")
}
return
case 256 + ld.R_PPC64_ADDR64:
r.Type = obj.R_ADDR
if targ.Type == obj.SDYNIMPORT {
// These happen in .toc sections
ld.Adddynsym(ld.Ctxt, targ)
rela := ld.Linklookup(ld.Ctxt, ".rela", 0)
ld.Addaddrplus(ld.Ctxt, rela, s, int64(r.Off))
ld.Adduint64(ld.Ctxt, rela, ld.ELF64_R_INFO(uint32(targ.Dynid), ld.R_PPC64_ADDR64))
ld.Adduint64(ld.Ctxt, rela, uint64(r.Add))
r.Type = 256 // ignore during relocsym
}
return
case 256 + ld.R_PPC64_TOC16:
r.Type = obj.R_POWER_TOC
r.Variant = ld.RV_POWER_LO | ld.RV_CHECK_OVERFLOW
return
case 256 + ld.R_PPC64_TOC16_LO:
r.Type = obj.R_POWER_TOC
r.Variant = ld.RV_POWER_LO
return
case 256 + ld.R_PPC64_TOC16_HA:
r.Type = obj.R_POWER_TOC
r.Variant = ld.RV_POWER_HA | ld.RV_CHECK_OVERFLOW
return
case 256 + ld.R_PPC64_TOC16_HI:
r.Type = obj.R_POWER_TOC
r.Variant = ld.RV_POWER_HI | ld.RV_CHECK_OVERFLOW
return
case 256 + ld.R_PPC64_TOC16_DS:
r.Type = obj.R_POWER_TOC
r.Variant = ld.RV_POWER_DS | ld.RV_CHECK_OVERFLOW
return
case 256 + ld.R_PPC64_TOC16_LO_DS:
r.Type = obj.R_POWER_TOC
r.Variant = ld.RV_POWER_DS
return
case 256 + ld.R_PPC64_REL16_LO:
r.Type = obj.R_PCREL
r.Variant = ld.RV_POWER_LO
r.Add += 2 // Compensate for relocation size of 2
return
case 256 + ld.R_PPC64_REL16_HI:
r.Type = obj.R_PCREL
r.Variant = ld.RV_POWER_HI | ld.RV_CHECK_OVERFLOW
r.Add += 2
return
case 256 + ld.R_PPC64_REL16_HA:
r.Type = obj.R_PCREL
r.Variant = ld.RV_POWER_HA | ld.RV_CHECK_OVERFLOW
r.Add += 2
return
}
// Handle references to ELF symbols from our own object files.
if targ.Type != obj.SDYNIMPORT {
return
}
// TODO(austin): Translate our relocations to ELF
ld.Diag("unsupported relocation for dynamic symbol %s (type=%d stype=%d)", targ.Name, r.Type, targ.Type)
}