Golang程序
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// Inferno utils/5l/asm.c
// http://code.google.com/p/inferno-os/source/browse/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/obj"
"cmd/link/internal/ld"
"fmt"
"log"
)
func gentext() {
}
// Preserve highest 8 bits of a, and do addition to lower 24-bit
// of a and b; used to adjust ARM branch intruction's target
func braddoff(a int32, b int32) int32 {
return int32((uint32(a))&0xff000000 | 0x00ffffff&uint32(a+b))
}
func adddynrela(rel *ld.LSym, s *ld.LSym, r *ld.Reloc) {
ld.Addaddrplus(ld.Ctxt, rel, s, int64(r.Off))
ld.Adduint32(ld.Ctxt, rel, ld.R_ARM_RELATIVE)
}
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_ARM_PLT32:
r.Type = obj.R_CALLARM
if targ.Type == obj.SDYNIMPORT {
addpltsym(ld.Ctxt, targ)
r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
}
return
case 256 + ld.R_ARM_THM_PC22: // R_ARM_THM_CALL
ld.Exitf("R_ARM_THM_CALL, are you using -marm?")
return
case 256 + ld.R_ARM_GOT32: // R_ARM_GOT_BREL
if targ.Type != obj.SDYNIMPORT {
addgotsyminternal(ld.Ctxt, targ)
} else {
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_ARM_GOT_PREL: // GOT(nil) + A - nil
if targ.Type != obj.SDYNIMPORT {
addgotsyminternal(ld.Ctxt, targ)
} else {
addgotsym(ld.Ctxt, targ)
}
r.Type = obj.R_PCREL
r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
r.Add += int64(targ.Got) + 4
return
case 256 + ld.R_ARM_GOTOFF: // R_ARM_GOTOFF32
r.Type = obj.R_GOTOFF
return
case 256 + ld.R_ARM_GOTPC: // R_ARM_BASE_PREL
r.Type = obj.R_PCREL
r.Sym = ld.Linklookup(ld.Ctxt, ".got", 0)
r.Add += 4
return
case 256 + ld.R_ARM_CALL:
r.Type = obj.R_CALLARM
if targ.Type == obj.SDYNIMPORT {
addpltsym(ld.Ctxt, targ)
r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
}
return
case 256 + ld.R_ARM_REL32: // R_ARM_REL32
r.Type = obj.R_PCREL
r.Add += 4
return
case 256 + ld.R_ARM_ABS32:
if targ.Type == obj.SDYNIMPORT {
ld.Diag("unexpected R_ARM_ABS32 relocation for dynamic symbol %s", targ.Name)
}
r.Type = obj.R_ADDR
return
// we can just ignore this, because we are targeting ARM V5+ anyway
case 256 + ld.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
case 256 + ld.R_ARM_PC24,
256 + ld.R_ARM_JUMP24:
r.Type = obj.R_CALLARM
if targ.Type == obj.SDYNIMPORT {
addpltsym(ld.Ctxt, targ)
r.Sym = ld.Linklookup(ld.Ctxt, ".plt", 0)
r.Add = int64(braddoff(int32(r.Add), targ.Plt/4))
}
return
}
// Handle references to ELF symbols from our own object files.
if targ.Type != obj.SDYNIMPORT {
return
}
switch r.Type {
case obj.R_CALLARM:
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_ARM_GLOB_DAT)) // we need a nil + A dynamic reloc
r.Type = obj.R_CONST // write r->add during relocsym
r.Sym = nil
return
}
}
ld.Ctxt.Cursym = s
ld.Diag("unsupported relocation for dynamic symbol %s (type=%d stype=%d)", targ.Name, r.Type, targ.Type)
}
func elfreloc1(r *ld.Reloc, sectoff int64) int {
ld.Thearch.Lput(uint32(sectoff))
elfsym := r.Xsym.Elfsym
switch r.Type {
default:
return -1
case obj.R_ADDR:
if r.Siz == 4 {
ld.Thearch.Lput(ld.R_ARM_ABS32 | uint32(elfsym)<<8)
} else {
return -1
}
case obj.R_PCREL:
if r.Siz == 4 {
ld.Thearch.Lput(ld.R_ARM_REL32 | uint32(elfsym)<<8)
} else {
return -1
}
case obj.R_CALLARM:
if r.Siz == 4 {
if r.Add&0xff000000 == 0xeb000000 { // BL
ld.Thearch.Lput(ld.R_ARM_CALL | uint32(elfsym)<<8)
} else {
ld.Thearch.Lput(ld.R_ARM_JUMP24 | uint32(elfsym)<<8)
}
} else {
return -1
}
case obj.R_TLS:
if r.Siz == 4 {
if ld.Buildmode == ld.BuildmodeCShared {
ld.Thearch.Lput(ld.R_ARM_TLS_IE32 | uint32(elfsym)<<8)
} else {
ld.Thearch.Lput(ld.R_ARM_TLS_LE32 | uint32(elfsym)<<8)
}
} else {
return -1
}
}
return 0
}
func elfsetupplt() {
plt := ld.Linklookup(ld.Ctxt, ".plt", 0)
got := ld.Linklookup(ld.Ctxt, ".got.plt", 0)
if plt.Size == 0 {
// str lr, [sp, #-4]!
ld.Adduint32(ld.Ctxt, plt, 0xe52de004)
// ldr lr, [pc, #4]
ld.Adduint32(ld.Ctxt, plt, 0xe59fe004)
// add lr, pc, lr
ld.Adduint32(ld.Ctxt, plt, 0xe08fe00e)
// ldr pc, [lr, #8]!
ld.Adduint32(ld.Ctxt, plt, 0xe5bef008)
// .word &GLOBAL_OFFSET_TABLE[0] - .
ld.Addpcrelplus(ld.Ctxt, plt, got, 4)
// the first .plt entry requires 3 .plt.got entries
ld.Adduint32(ld.Ctxt, got, 0)
ld.Adduint32(ld.Ctxt, got, 0)
ld.Adduint32(ld.Ctxt, got, 0)
}
}
func machoreloc1(r *ld.Reloc, sectoff int64) int {
var v uint32
rs := r.Xsym
if rs.Type == obj.SHOSTOBJ || r.Type == obj.R_CALLARM {
if rs.Dynid < 0 {
ld.Diag("reloc %d to non-macho symbol %s type=%d", r.Type, rs.Name, rs.Type)
return -1
}
v = uint32(rs.Dynid)
v |= 1 << 27 // external relocation
} else {
v = uint32(rs.Sect.Extnum)
if v == 0 {
ld.Diag("reloc %d to symbol %s in non-macho section %s type=%d", r.Type, rs.Name, rs.Sect.Name, rs.Type)
return -1
}
}
switch r.Type {
default:
return -1
case obj.R_ADDR:
v |= ld.MACHO_GENERIC_RELOC_VANILLA << 28
case obj.R_CALLARM:
v |= 1 << 24 // pc-relative bit
v |= ld.MACHO_ARM_RELOC_BR24 << 28
}
switch r.Siz {
default:
return -1
case 1:
v |= 0 << 25
case 2:
v |= 1 << 25
case 4:
v |= 2 << 25
case 8:
v |= 3 << 25
}
ld.Thearch.Lput(uint32(sectoff))
ld.Thearch.Lput(v)
return 0
}
func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
if ld.Linkmode == ld.LinkExternal {
switch r.Type {
case obj.R_CALLARM:
r.Done = 0
// set up addend for eventual relocation via outer symbol.
rs := r.Sym
r.Xadd = r.Add
if r.Xadd&0x800000 != 0 {
r.Xadd |= ^0xffffff
}
r.Xadd *= 4
for rs.Outer != nil {
r.Xadd += ld.Symaddr(rs) - ld.Symaddr(rs.Outer)
rs = rs.Outer
}
if rs.Type != obj.SHOSTOBJ && rs.Sect == nil {
ld.Diag("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 ld.HEADTYPE == obj.Hdarwin {
r.Xadd -= ld.Symaddr(s) + int64(r.Off)
}
*val = int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&uint32(r.Xadd/4))))
return 0
}
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
// The following three arch specific relocations are only for generation of
// Linux/ARM ELF's PLT entry (3 assembler instruction)
case obj.R_PLT0: // add ip, pc, #0xXX00000
if ld.Symaddr(ld.Linklookup(ld.Ctxt, ".got.plt", 0)) < ld.Symaddr(ld.Linklookup(ld.Ctxt, ".plt", 0)) {
ld.Diag(".got.plt should be placed after .plt section.")
}
*val = 0xe28fc600 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ld.Linklookup(ld.Ctxt, ".plt", 0))+int64(r.Off))+r.Add)) >> 20))
return 0
case obj.R_PLT1: // add ip, ip, #0xYY000
*val = 0xe28cca00 + (0xff & (int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ld.Linklookup(ld.Ctxt, ".plt", 0))+int64(r.Off))+r.Add+4)) >> 12))
return 0
case obj.R_PLT2: // ldr pc, [ip, #0xZZZ]!
*val = 0xe5bcf000 + (0xfff & int64(uint32(ld.Symaddr(r.Sym)-(ld.Symaddr(ld.Linklookup(ld.Ctxt, ".plt", 0))+int64(r.Off))+r.Add+8)))
return 0
case obj.R_CALLARM: // bl XXXXXX or b YYYYYY
*val = int64(braddoff(int32(0xff000000&uint32(r.Add)), int32(0xffffff&uint32((ld.Symaddr(r.Sym)+int64((uint32(r.Add))*4)-(s.Value+int64(r.Off)))/4))))
return 0
}
return -1
}
func archrelocvariant(r *ld.Reloc, s *ld.LSym, t int64) int64 {
log.Fatalf("unexpected relocation variant")
return t
}
func addpltreloc(ctxt *ld.Link, plt *ld.LSym, got *ld.LSym, sym *ld.LSym, typ int) *ld.Reloc {
r := ld.Addrel(plt)
r.Sym = got
r.Off = int32(plt.Size)
r.Siz = 4
r.Type = int32(typ)
r.Add = int64(sym.Got) - 8
plt.Reachable = true
plt.Size += 4
ld.Symgrow(ctxt, plt, plt.Size)
return r
}
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()
}
// .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 {
ld.Diag("addpltsym: unsupported binary format")
}
}
func addgotsyminternal(ctxt *ld.Link, s *ld.LSym) {
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 {
ld.Diag("addgotsyminternal: unsupported binary format")
}
}
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_ARM_GLOB_DAT))
} else {
ld.Diag("addgotsym: unsupported binary format")
}
}
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())
}
/* 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.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))
}
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.Hdarwin:
if ld.Linkmode == ld.LinkExternal {
ld.Machoemitreloc()
}
}
}
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))
case obj.Hdarwin:
ld.Asmbmacho()
}
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))
}
}