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// Inferno utils/5l/asm.c
// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/5l/asm.c
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
// Portions Copyright © 1997-1999 Vita Nuova Limited
// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
// Portions Copyright © 2004,2006 Bruce Ellis
// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
// Portions Copyright © 2009 The Go Authors. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package arm
import (
"cmd/internal/objabi"
"cmd/internal/sys"
"cmd/link/internal/ld"
"cmd/link/internal/sym"
"debug/elf"
"fmt"
"log"
)
// This assembler:
//
// .align 2
// local.dso_init:
// ldr r0, .Lmoduledata
// .Lloadfrom:
// ldr r0, [r0]
// b runtime.addmoduledata@plt
// .align 2
// .Lmoduledata:
// .word local.moduledata(GOT_PREL) + (. - (.Lloadfrom + 4))
// assembles to:
//
// 00000000 <local.dso_init>:
// 0: e59f0004 ldr r0, [pc, #4] ; c <local.dso_init+0xc>
// 4: e5900000 ldr r0, [r0]
// 8: eafffffe b 0 <runtime.addmoduledata>
// 8: R_ARM_JUMP24 runtime.addmoduledata
// c: 00000004 .word 0x00000004
// c: R_ARM_GOT_PREL local.moduledata
func gentext(ctxt *ld.Link) {
if !ctxt.DynlinkingGo() {
return
}
addmoduledata := ctxt.Syms.Lookup("runtime.addmoduledata", 0)
if addmoduledata.Type == sym.STEXT && ctxt.BuildMode != ld.BuildModePlugin {
// we're linking a module containing the runtime -> no need for
// an init function
return
}
addmoduledata.Attr |= sym.AttrReachable
initfunc := ctxt.Syms.Lookup("go.link.addmoduledata", 0)
initfunc.Type = sym.STEXT
initfunc.Attr |= sym.AttrLocal
initfunc.Attr |= sym.AttrReachable
o := func(op uint32) {
initfunc.AddUint32(ctxt.Arch, op)
}
o(0xe59f0004)
o(0xe08f0000)
o(0xeafffffe)
rel := initfunc.AddRel()
rel.Off = 8
rel.Siz = 4
rel.Sym = ctxt.Syms.Lookup("runtime.addmoduledata", 0)
rel.Type = objabi.R_CALLARM
rel.Add = 0xeafffffe // vomit
o(0x00000000)
rel = initfunc.AddRel()
rel.Off = 12
rel.Siz = 4
rel.Sym = ctxt.Moduledata
rel.Type = objabi.R_PCREL
rel.Add = 4
if ctxt.BuildMode == ld.BuildModePlugin {
ctxt.Textp = append(ctxt.Textp, addmoduledata)
}
ctxt.Textp = append(ctxt.Textp, initfunc)
initarray_entry := ctxt.Syms.Lookup("go.link.addmoduledatainit", 0)
initarray_entry.Attr |= sym.AttrReachable
initarray_entry.Attr |= sym.AttrLocal
initarray_entry.Type = sym.SINITARR
initarray_entry.AddAddr(ctxt.Arch, initfunc)
}
// Preserve highest 8 bits of a, and do addition to lower 24-bit
// of a and b; used to adjust ARM branch instruction's target
func braddoff(a int32, b int32) int32 {
return int32((uint32(a))&0xff000000 | 0x00ffffff&uint32(a+b))
}
func adddynrel(ctxt *ld.Link, s *sym.Symbol, r *sym.Reloc) bool {
targ := r.Sym
switch r.Type {
default:
if r.Type >= 256 {
ld.Errorf(s, "unexpected relocation type %d (%s)", r.Type, sym.RelocName(ctxt.Arch, r.Type))
return false
}
// Handle relocations found in ELF object files.
case 256 + objabi.RelocType(elf.R_ARM_PLT32):
r.Type = objabi.R_CALLARM
if targ.Type == sym.SDYNIMPORT {
addpltsym(ctxt, targ)
r.Sym = ctxt.Syms.Lookup(".plt", 0)
r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
}
return true
case 256 + objabi.RelocType(elf.R_ARM_THM_PC22): // R_ARM_THM_CALL
ld.Exitf("R_ARM_THM_CALL, are you using -marm?")
return false
case 256 + objabi.RelocType(elf.R_ARM_GOT32): // R_ARM_GOT_BREL
if targ.Type != sym.SDYNIMPORT {
addgotsyminternal(ctxt, targ)
} else {
addgotsym(ctxt, targ)
}
r.Type = objabi.R_CONST // write r->add during relocsym
r.Sym = nil
r.Add += int64(targ.Got)
return true
case 256 + objabi.RelocType(elf.R_ARM_GOT_PREL): // GOT(nil) + A - nil
if targ.Type != sym.SDYNIMPORT {
addgotsyminternal(ctxt, targ)
} else {
addgotsym(ctxt, targ)
}
r.Type = objabi.R_PCREL
r.Sym = ctxt.Syms.Lookup(".got", 0)
r.Add += int64(targ.Got) + 4
return true
case 256 + objabi.RelocType(elf.R_ARM_GOTOFF): // R_ARM_GOTOFF32
r.Type = objabi.R_GOTOFF
return true
case 256 + objabi.RelocType(elf.R_ARM_GOTPC): // R_ARM_BASE_PREL
r.Type = objabi.R_PCREL
r.Sym = ctxt.Syms.Lookup(".got", 0)
r.Add += 4
return true
case 256 + objabi.RelocType(elf.R_ARM_CALL):
r.Type = objabi.R_CALLARM
if targ.Type == sym.SDYNIMPORT {
addpltsym(ctxt, targ)
r.Sym = ctxt.Syms.Lookup(".plt", 0)
r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
}
return true
case 256 + objabi.RelocType(elf.R_ARM_REL32): // R_ARM_REL32
r.Type = objabi.R_PCREL
r.Add += 4
return true
case 256 + objabi.RelocType(elf.R_ARM_ABS32):
if targ.Type == sym.SDYNIMPORT {
ld.Errorf(s, "unexpected R_ARM_ABS32 relocation for dynamic symbol %s", targ.Name)
}
r.Type = objabi.R_ADDR
return true
// we can just ignore this, because we are targeting ARM V5+ anyway
case 256 + objabi.RelocType(elf.R_ARM_V4BX):
if r.Sym != nil {
// R_ARM_V4BX is ABS relocation, so this symbol is a dummy symbol, ignore it
r.Sym.Type = 0
}
r.Sym = nil
return true
case 256 + objabi.RelocType(elf.R_ARM_PC24),
256 + objabi.RelocType(elf.R_ARM_JUMP24):
r.Type = objabi.R_CALLARM
if targ.Type == sym.SDYNIMPORT {
addpltsym(ctxt, targ)
r.Sym = ctxt.Syms.Lookup(".plt", 0)
r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
}
return true
}
// Handle references to ELF symbols from our own object files.
if targ.Type != sym.SDYNIMPORT {
return true
}
switch r.Type {
case objabi.R_CALLARM:
addpltsym(ctxt, targ)
r.Sym = ctxt.Syms.Lookup(".plt", 0)
r.Add = int64(targ.Plt)
return true
case objabi.R_ADDR:
if s.Type != sym.SDATA {
break
}
if ctxt.IsELF {
ld.Adddynsym(ctxt, targ)
rel := ctxt.Syms.Lookup(".rel", 0)
rel.AddAddrPlus(ctxt.Arch, s, int64(r.Off))
rel.AddUint32(ctxt.Arch, ld.ELF32_R_INFO(uint32(targ.Dynid), uint32(elf.R_ARM_GLOB_DAT))) // we need a nil + A dynamic reloc
r.Type = objabi.R_CONST // write r->add during relocsym
r.Sym = nil
return true
}
}
return false
}
func elfreloc1(ctxt *ld.Link, r *sym.Reloc, sectoff int64) bool {
ctxt.Out.Write32(uint32(sectoff))
elfsym := r.Xsym.ElfsymForReloc()
switch r.Type {
default:
return false
case objabi.R_ADDR:
if r.Siz == 4 {
ctxt.Out.Write32(uint32(elf.R_ARM_ABS32) | uint32(elfsym)<<8)
} else {
return false
}
case objabi.R_PCREL:
if r.Siz == 4 {
ctxt.Out.Write32(uint32(elf.R_ARM_REL32) | uint32(elfsym)<<8)
} else {
return false
}
case objabi.R_CALLARM:
if r.Siz == 4 {
if r.Add&0xff000000 == 0xeb000000 { // BL
ctxt.Out.Write32(uint32(elf.R_ARM_CALL) | uint32(elfsym)<<8)
} else {
ctxt.Out.Write32(uint32(elf.R_ARM_JUMP24) | uint32(elfsym)<<8)
}
} else {
return false
}
case objabi.R_TLS_LE:
ctxt.Out.Write32(uint32(elf.R_ARM_TLS_LE32) | uint32(elfsym)<<8)
case objabi.R_TLS_IE:
ctxt.Out.Write32(uint32(elf.R_ARM_TLS_IE32) | uint32(elfsym)<<8)
case objabi.R_GOTPCREL:
if r.Siz == 4 {
ctxt.Out.Write32(uint32(elf.R_ARM_GOT_PREL) | uint32(elfsym)<<8)
} else {
return false
}
}
return true
}
func elfsetupplt(ctxt *ld.Link) {
plt := ctxt.Syms.Lookup(".plt", 0)
got := ctxt.Syms.Lookup(".got.plt", 0)
if plt.Size == 0 {
// str lr, [sp, #-4]!
plt.AddUint32(ctxt.Arch, 0xe52de004)
// ldr lr, [pc, #4]
plt.AddUint32(ctxt.Arch, 0xe59fe004)
// add lr, pc, lr
plt.AddUint32(ctxt.Arch, 0xe08fe00e)
// ldr pc, [lr, #8]!
plt.AddUint32(ctxt.Arch, 0xe5bef008)
// .word &GLOBAL_OFFSET_TABLE[0] - .
plt.AddPCRelPlus(ctxt.Arch, got, 4)
// the first .plt entry requires 3 .plt.got entries
got.AddUint32(ctxt.Arch, 0)
got.AddUint32(ctxt.Arch, 0)
got.AddUint32(ctxt.Arch, 0)
}
}
func machoreloc1(arch *sys.Arch, out *ld.OutBuf, s *sym.Symbol, r *sym.Reloc, sectoff int64) bool {
var v uint32
rs := r.Xsym
if r.Type == objabi.R_PCREL {
if rs.Type == sym.SHOSTOBJ {
ld.Errorf(s, "pc-relative relocation of external symbol is not supported")
return false
}
if r.Siz != 4 {
return false
}
// emit a pair of "scattered" relocations that
// resolve to the difference of section addresses of
// the symbol and the instruction
// this value is added to the field being relocated
o1 := uint32(sectoff)
o1 |= 1 << 31 // scattered bit
o1 |= ld.MACHO_ARM_RELOC_SECTDIFF << 24
o1 |= 2 << 28 // size = 4
o2 := uint32(0)
o2 |= 1 << 31 // scattered bit
o2 |= ld.MACHO_ARM_RELOC_PAIR << 24
o2 |= 2 << 28 // size = 4
out.Write32(o1)
out.Write32(uint32(ld.Symaddr(rs)))
out.Write32(o2)
out.Write32(uint32(s.Value + int64(r.Off)))
return true
}
if rs.Type == sym.SHOSTOBJ || r.Type == objabi.R_CALLARM {
if rs.Dynid < 0 {
ld.Errorf(s, "reloc %d (%s) to non-macho symbol %s type=%d (%s)", r.Type, sym.RelocName(arch, r.Type), rs.Name, rs.Type, rs.Type)
return false
}
v = uint32(rs.Dynid)
v |= 1 << 27 // external relocation
} else {
v = uint32(rs.Sect.Extnum)
if v == 0 {
ld.Errorf(s, "reloc %d (%s) to symbol %s in non-macho section %s type=%d (%s)", r.Type, sym.RelocName(arch, r.Type), rs.Name, rs.Sect.Name, rs.Type, rs.Type)
return false
}
}
switch r.Type {
default:
return false
case objabi.R_ADDR:
v |= ld.MACHO_GENERIC_RELOC_VANILLA << 28
case objabi.R_CALLARM:
v |= 1 << 24 // pc-relative bit
v |= ld.MACHO_ARM_RELOC_BR24 << 28
}
switch r.Siz {
default:
return false
case 1:
v |= 0 << 25
case 2:
v |= 1 << 25
case 4:
v |= 2 << 25
case 8:
v |= 3 << 25
}
out.Write32(uint32(sectoff))
out.Write32(v)
return true
}
// sign extend a 24-bit integer
func signext24(x int64) int32 {
return (int32(x) << 8) >> 8
}
// encode an immediate in ARM's imm12 format. copied from ../../../internal/obj/arm/asm5.go
func immrot(v uint32) uint32 {
for i := 0; i < 16; i++ {
if v&^0xff == 0 {
return uint32(i<<8) | v | 1<<25
}
v = v<<2 | v>>30
}
return 0
}
// Convert the direct jump relocation r to refer to a trampoline if the target is too far
func trampoline(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol) {
switch r.Type {
case objabi.R_CALLARM:
// r.Add is the instruction
// low 24-bit encodes the target address
t := (ld.Symaddr(r.Sym) + int64(signext24(r.Add&0xffffff)*4) - (s.Value + int64(r.Off))) / 4
if t > 0x7fffff || t < -0x800000 || (*ld.FlagDebugTramp > 1 && s.File != r.Sym.File) {
// direct call too far, need to insert trampoline.
// look up existing trampolines first. if we found one within the range
// of direct call, we can reuse it. otherwise create a new one.
offset := (signext24(r.Add&0xffffff) + 2) * 4
var tramp *sym.Symbol
for i := 0; ; i++ {
name := r.Sym.Name + fmt.Sprintf("%+d-tramp%d", offset, i)
tramp = ctxt.Syms.Lookup(name, int(r.Sym.Version))
if tramp.Type == sym.SDYNIMPORT {
// don't reuse trampoline defined in other module
continue
}
if tramp.Value == 0 {
// either the trampoline does not exist -- we need to create one,
// or found one the address which is not assigned -- this will be
// laid down immediately after the current function. use this one.
break
}
t = (ld.Symaddr(tramp) - 8 - (s.Value + int64(r.Off))) / 4
if t >= -0x800000 && t < 0x7fffff {
// found an existing trampoline that is not too far
// we can just use it
break
}
}
if tramp.Type == 0 {
// trampoline does not exist, create one
ctxt.AddTramp(tramp)
if ctxt.DynlinkingGo() {
if immrot(uint32(offset)) == 0 {
ld.Errorf(s, "odd offset in dynlink direct call: %v+%d", r.Sym, offset)
}
gentrampdyn(ctxt.Arch, tramp, r.Sym, int64(offset))
} else if ctxt.BuildMode == ld.BuildModeCArchive || ctxt.BuildMode == ld.BuildModeCShared || ctxt.BuildMode == ld.BuildModePIE {
gentramppic(ctxt.Arch, tramp, r.Sym, int64(offset))
} else {
gentramp(ctxt.Arch, ctxt.LinkMode, tramp, r.Sym, int64(offset))
}
}
// modify reloc to point to tramp, which will be resolved later
r.Sym = tramp
r.Add = r.Add&0xff000000 | 0xfffffe // clear the offset embedded in the instruction
r.Done = false
}
default:
ld.Errorf(s, "trampoline called with non-jump reloc: %d (%s)", r.Type, sym.RelocName(ctxt.Arch, r.Type))
}
}
// generate a trampoline to target+offset
func gentramp(arch *sys.Arch, linkmode ld.LinkMode, tramp, target *sym.Symbol, offset int64) {
tramp.Size = 12 // 3 instructions
tramp.P = make([]byte, tramp.Size)
t := ld.Symaddr(target) + int64(offset)
o1 := uint32(0xe5900000 | 11<<12 | 15<<16) // MOVW (R15), R11 // R15 is actual pc + 8
o2 := uint32(0xe12fff10 | 11) // JMP (R11)
o3 := uint32(t) // WORD $target
arch.ByteOrder.PutUint32(tramp.P, o1)
arch.ByteOrder.PutUint32(tramp.P[4:], o2)
arch.ByteOrder.PutUint32(tramp.P[8:], o3)
if linkmode == ld.LinkExternal {
r := tramp.AddRel()
r.Off = 8
r.Type = objabi.R_ADDR
r.Siz = 4
r.Sym = target
r.Add = offset
}
}
// generate a trampoline to target+offset in position independent code
func gentramppic(arch *sys.Arch, tramp, target *sym.Symbol, offset int64) {
tramp.Size = 16 // 4 instructions
tramp.P = make([]byte, tramp.Size)
o1 := uint32(0xe5900000 | 11<<12 | 15<<16 | 4) // MOVW 4(R15), R11 // R15 is actual pc + 8
o2 := uint32(0xe0800000 | 11<<12 | 15<<16 | 11) // ADD R15, R11, R11
o3 := uint32(0xe12fff10 | 11) // JMP (R11)
o4 := uint32(0) // WORD $(target-pc) // filled in with relocation
arch.ByteOrder.PutUint32(tramp.P, o1)
arch.ByteOrder.PutUint32(tramp.P[4:], o2)
arch.ByteOrder.PutUint32(tramp.P[8:], o3)
arch.ByteOrder.PutUint32(tramp.P[12:], o4)
r := tramp.AddRel()
r.Off = 12
r.Type = objabi.R_PCREL
r.Siz = 4
r.Sym = target
r.Add = offset + 4
}
// generate a trampoline to target+offset in dynlink mode (using GOT)
func gentrampdyn(arch *sys.Arch, tramp, target *sym.Symbol, offset int64) {
tramp.Size = 20 // 5 instructions
o1 := uint32(0xe5900000 | 11<<12 | 15<<16 | 8) // MOVW 8(R15), R11 // R15 is actual pc + 8
o2 := uint32(0xe0800000 | 11<<12 | 15<<16 | 11) // ADD R15, R11, R11
o3 := uint32(0xe5900000 | 11<<12 | 11<<16) // MOVW (R11), R11
o4 := uint32(0xe12fff10 | 11) // JMP (R11)
o5 := uint32(0) // WORD $target@GOT // filled in with relocation
o6 := uint32(0)
if offset != 0 {
// insert an instruction to add offset
tramp.Size = 24 // 6 instructions
o6 = o5
o5 = o4
o4 = uint32(0xe2800000 | 11<<12 | 11<<16 | immrot(uint32(offset))) // ADD $offset, R11, R11
o1 = uint32(0xe5900000 | 11<<12 | 15<<16 | 12) // MOVW 12(R15), R11
}
tramp.P = make([]byte, tramp.Size)
arch.ByteOrder.PutUint32(tramp.P, o1)
arch.ByteOrder.PutUint32(tramp.P[4:], o2)
arch.ByteOrder.PutUint32(tramp.P[8:], o3)
arch.ByteOrder.PutUint32(tramp.P[12:], o4)
arch.ByteOrder.PutUint32(tramp.P[16:], o5)
if offset != 0 {
arch.ByteOrder.PutUint32(tramp.P[20:], o6)
}
r := tramp.AddRel()
r.Off = 16
r.Type = objabi.R_GOTPCREL
r.Siz = 4
r.Sym = target
r.Add = 8
if offset != 0 {
// increase reloc offset by 4 as we inserted an ADD instruction
r.Off = 20
r.Add = 12
}
}
func archreloc(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, val *int64) bool {
if ctxt.LinkMode == ld.LinkExternal {
switch r.Type {
case objabi.R_CALLARM:
r.Done = false
// set up addend for eventual relocation via outer symbol.
rs := r.Sym
r.Xadd = int64(signext24(r.Add & 0xffffff))
r.Xadd *= 4
for rs.Outer != nil {
r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
rs = rs.Outer
}
if rs.Type != sym.SHOSTOBJ && rs.Type != sym.SDYNIMPORT && rs.Sect == nil {
ld.Errorf(s, "missing section for %s", rs.Name)
}
r.Xsym = rs
// ld64 for arm seems to want the symbol table to contain offset
// into the section rather than pseudo virtual address that contains
// the section load address.
// we need to compensate that by removing the instruction's address
// from addend.
if ctxt.HeadType == objabi.Hdarwin {
r.Xadd -= ld.Symaddr(s) + int64(r.Off)
}
if r.Xadd/4 > 0x7fffff || r.Xadd/4 < -0x800000 {
ld.Errorf(s, "direct call too far %d", r.Xadd/4)
}
*val = int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&uint32(r.Xadd/4))))
return true
}
return false
}
switch r.Type {
case objabi.R_CONST:
*val = r.Add
return true
case objabi.R_GOTOFF:
*val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ctxt.Syms.Lookup(".got", 0))
return true
// The following three arch specific relocations are only for generation of
// Linux/ARM ELF's PLT entry (3 assembler instruction)
case objabi.R_PLT0: // add ip, pc, #0xXX00000
if ld.Symaddr(ctxt.Syms.Lookup(".got.plt", 0)) < ld.Symaddr(ctxt.Syms.Lookup(".plt", 0)) {
ld.Errorf(s, ".got.plt should be placed after .plt section.")
}
*val = 0xe28fc600 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ctxt.Syms.Lookup(".plt", 0))+int64(r.Off))+r.Add)) >> 20))
return true
case objabi.R_PLT1: // add ip, ip, #0xYY000
*val = 0xe28cca00 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ctxt.Syms.Lookup(".plt", 0))+int64(r.Off))+r.Add+4)) >> 12))
return true
case objabi.R_PLT2: // ldr pc, [ip, #0xZZZ]!
*val = 0xe5bcf000 + (0xfff & int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ctxt.Syms.Lookup(".plt", 0))+int64(r.Off))+r.Add+8)))
return true
case objabi.R_CALLARM: // bl XXXXXX or b YYYYYY
// r.Add is the instruction
// low 24-bit encodes the target address
t := (ld.Symaddr(r.Sym) + int64(signext24(r.Add&0xffffff)*4) - (s.Value + int64(r.Off))) / 4
if t > 0x7fffff || t < -0x800000 {
ld.Errorf(s, "direct call too far: %s %x", r.Sym.Name, t)
}
*val = int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&t)))
return true
}
return false
}
func archrelocvariant(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, t int64) int64 {
log.Fatalf("unexpected relocation variant")
return t
}
func addpltreloc(ctxt *ld.Link, plt *sym.Symbol, got *sym.Symbol, s *sym.Symbol, typ objabi.RelocType) *sym.Reloc {
r := plt.AddRel()
r.Sym = got
r.Off = int32(plt.Size)
r.Siz = 4
r.Type = typ
r.Add = int64(s.Got) - 8
plt.Attr |= sym.AttrReachable
plt.Size += 4
plt.Grow(plt.Size)
return r
}
func addpltsym(ctxt *ld.Link, s *sym.Symbol) {
if s.Plt >= 0 {
return
}
ld.Adddynsym(ctxt, s)
if ctxt.IsELF {
plt := ctxt.Syms.Lookup(".plt", 0)
got := ctxt.Syms.Lookup(".got.plt", 0)
rel := ctxt.Syms.Lookup(".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.
got.AddAddrPlus(ctxt.Arch, plt, 0)
// .plt entry, this depends on the .got entry
s.Plt = int32(plt.Size)
addpltreloc(ctxt, plt, got, s, objabi.R_PLT0) // add lr, pc, #0xXX00000
addpltreloc(ctxt, plt, got, s, objabi.R_PLT1) // add lr, lr, #0xYY000
addpltreloc(ctxt, plt, got, s, objabi.R_PLT2) // ldr pc, [lr, #0xZZZ]!
// rel
rel.AddAddrPlus(ctxt.Arch, got, int64(s.Got))
rel.AddUint32(ctxt.Arch, ld.ELF32_R_INFO(uint32(s.Dynid), uint32(elf.R_ARM_JUMP_SLOT)))
} else {
ld.Errorf(s, "addpltsym: unsupported binary format")
}
}
func addgotsyminternal(ctxt *ld.Link, s *sym.Symbol) {
if s.Got >= 0 {
return
}
got := ctxt.Syms.Lookup(".got", 0)
s.Got = int32(got.Size)
got.AddAddrPlus(ctxt.Arch, s, 0)
if ctxt.IsELF {
} else {
ld.Errorf(s, "addgotsyminternal: unsupported binary format")
}
}
func addgotsym(ctxt *ld.Link, s *sym.Symbol) {
if s.Got >= 0 {
return
}
ld.Adddynsym(ctxt, s)
got := ctxt.Syms.Lookup(".got", 0)
s.Got = int32(got.Size)
got.AddUint32(ctxt.Arch, 0)
if ctxt.IsELF {
rel := ctxt.Syms.Lookup(".rel", 0)
rel.AddAddrPlus(ctxt.Arch, got, int64(s.Got))
rel.AddUint32(ctxt.Arch, ld.ELF32_R_INFO(uint32(s.Dynid), uint32(elf.R_ARM_GLOB_DAT)))
} else {
ld.Errorf(s, "addgotsym: unsupported binary format")
}
}
func asmb(ctxt *ld.Link) {
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f asmb\n", ld.Cputime())
}
if ctxt.IsELF {
ld.Asmbelfsetup()
}
sect := ld.Segtext.Sections[0]
ctxt.Out.SeekSet(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
ld.Codeblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
for _, sect = range ld.Segtext.Sections[1:] {
ctxt.Out.SeekSet(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
ld.Datblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
}
if ld.Segrodata.Filelen > 0 {
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f rodatblk\n", ld.Cputime())
}
ctxt.Out.SeekSet(int64(ld.Segrodata.Fileoff))
ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
}
if ld.Segrelrodata.Filelen > 0 {
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f relrodatblk\n", ld.Cputime())
}
ctxt.Out.SeekSet(int64(ld.Segrelrodata.Fileoff))
ld.Datblk(ctxt, int64(ld.Segrelrodata.Vaddr), int64(ld.Segrelrodata.Filelen))
}
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f datblk\n", ld.Cputime())
}
ctxt.Out.SeekSet(int64(ld.Segdata.Fileoff))
ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))
ctxt.Out.SeekSet(int64(ld.Segdwarf.Fileoff))
ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))
machlink := uint32(0)
if ctxt.HeadType == objabi.Hdarwin {
machlink = uint32(ld.Domacholink(ctxt))
}
/* output symbol table */
ld.Symsize = 0
ld.Lcsize = 0
symo := uint32(0)
if !*ld.FlagS {
// TODO: rationalize
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f sym\n", ld.Cputime())
}
switch ctxt.HeadType {
default:
if ctxt.IsELF {
symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound)))
}
case objabi.Hplan9:
symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)
case objabi.Hdarwin:
symo = uint32(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(*ld.FlagRound))) + uint64(machlink))
}
ctxt.Out.SeekSet(int64(symo))
switch ctxt.HeadType {
default:
if ctxt.IsELF {
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f elfsym\n", ld.Cputime())
}
ld.Asmelfsym(ctxt)
ctxt.Out.Flush()
ctxt.Out.Write(ld.Elfstrdat)
if ctxt.LinkMode == ld.LinkExternal {
ld.Elfemitreloc(ctxt)
}
}
case objabi.Hplan9:
ld.Asmplan9sym(ctxt)
ctxt.Out.Flush()
sym := ctxt.Syms.Lookup("pclntab", 0)
if sym != nil {
ld.Lcsize = int32(len(sym.P))
ctxt.Out.Write(sym.P)
ctxt.Out.Flush()
}
case objabi.Hdarwin:
if ctxt.LinkMode == ld.LinkExternal {
ld.Machoemitreloc(ctxt)
}
}
}
if ctxt.Debugvlog != 0 {
ctxt.Logf("%5.2f header\n", ld.Cputime())
}
ctxt.Out.SeekSet(0)
switch ctxt.HeadType {
default:
case objabi.Hplan9: /* plan 9 */
ctxt.Out.Write32b(0x647) /* magic */
ctxt.Out.Write32b(uint32(ld.Segtext.Filelen)) /* sizes */
ctxt.Out.Write32b(uint32(ld.Segdata.Filelen))
ctxt.Out.Write32b(uint32(ld.Segdata.Length - ld.Segdata.Filelen))
ctxt.Out.Write32b(uint32(ld.Symsize)) /* nsyms */
ctxt.Out.Write32b(uint32(ld.Entryvalue(ctxt))) /* va of entry */
ctxt.Out.Write32b(0)
ctxt.Out.Write32b(uint32(ld.Lcsize))
case objabi.Hlinux,
objabi.Hfreebsd,
objabi.Hnetbsd,
objabi.Hopenbsd,
objabi.Hnacl:
ld.Asmbelf(ctxt, int64(symo))
case objabi.Hdarwin:
ld.Asmbmacho(ctxt)
}
ctxt.Out.Flush()
if *ld.FlagC {
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))
}
}