func xfol(ctxt *liblink.Link, p *liblink.Prog, last **liblink.Prog) {
var q *liblink.Prog
var i int
var a int
loop:
if p == nil {
return
}
if p.As == AJMP {
q = p.Pcond
if q != nil && q.As != ATEXT {
/* mark instruction as done and continue layout at target of jump */
p.Mark = 1
p = q
if p.Mark == 0 {
goto loop
}
}
}
if p.Mark != 0 {
/*
* p goes here, but already used it elsewhere.
* copy up to 4 instructions or else branch to other copy.
*/
i = 0
q = p
for ; i < 4; (func() { i++; q = q.Link })() {
if q == nil {
break
}
if q == *last {
break
}
a = int(q.As)
if a == ANOP {
i--
continue
}
if nofollow(a) != 0 || pushpop(a) != 0 {
break // NOTE(rsc): arm does goto copy
}
if q.Pcond == nil || q.Pcond.Mark != 0 {
continue
}
if a == ACALL || a == ALOOP {
continue
}
for {
if p.As == ANOP {
p = p.Link
continue
}
q = liblink.Copyp(ctxt, p)
p = p.Link
q.Mark = 1
(*last).Link = q
*last = q
if int(q.As) != a || q.Pcond == nil || q.Pcond.Mark != 0 {
continue
}
q.As = int16(relinv(int(q.As)))
p = q.Pcond
q.Pcond = q.Link
q.Link = p
xfol(ctxt, q.Link, last)
p = q.Link
if p.Mark != 0 {
return
}
goto loop
/* */
}
}
q = ctxt.Arch.Prg()
q.As = AJMP
q.Lineno = p.Lineno
q.To.Type_ = D_BRANCH
q.To.Offset = p.Pc
q.Pcond = p
p = q
}
/* emit p */
p.Mark = 1
(*last).Link = p
*last = p
a = int(p.As)
/* continue loop with what comes after p */
if nofollow(a) != 0 {
return
}
if p.Pcond != nil && a != ACALL {
/*
* some kind of conditional branch.
* recurse to follow one path.
* continue loop on the other.
*/
q = liblink.Brchain(ctxt, p.Pcond)
if q != nil {
p.Pcond = q
}
q = liblink.Brchain(ctxt, p.Link)
if q != nil {
p.Link = q
}
if p.From.Type_ == D_CONST {
if p.From.Offset == 1 {
/*
* expect conditional jump to be taken.
* rewrite so that's the fall-through case.
*/
p.As = int16(relinv(a))
q = p.Link
p.Link = p.Pcond
p.Pcond = q
}
} else {
q = p.Link
if q.Mark != 0 {
if a != ALOOP {
p.As = int16(relinv(a))
p.Link = p.Pcond
p.Pcond = q
}
}
}
xfol(ctxt, p.Link, last)
if p.Pcond.Mark != 0 {
return
}
p = p.Pcond
goto loop
}
p = p.Link
goto loop
}
func addstacksplit(ctxt *liblink.Link, cursym *liblink.LSym) {
var p *liblink.Prog
var q *liblink.Prog
var p1 *liblink.Prog
var p2 *liblink.Prog
var autoffset int32
var deltasp int32
var a int
var pcsize int
var textstksiz int64
var textarg int64
if ctxt.Tlsg == nil {
ctxt.Tlsg = liblink.Linklookup(ctxt, "runtime.tlsg", 0)
}
if ctxt.Symmorestack[0] == nil {
ctxt.Symmorestack[0] = liblink.Linklookup(ctxt, "runtime.morestack", 0)
ctxt.Symmorestack[1] = liblink.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
}
if ctxt.Headtype == liblink.Hplan9 && ctxt.Plan9privates == nil {
ctxt.Plan9privates = liblink.Linklookup(ctxt, "_privates", 0)
}
ctxt.Cursym = cursym
if cursym.Text == nil || cursym.Text.Link == nil {
return
}
p = cursym.Text
parsetextconst(p.To.Offset, &textstksiz, &textarg)
autoffset = int32(textstksiz)
if autoffset < 0 {
autoffset = 0
}
cursym.Args = int32(p.To.Offset >> 32)
cursym.Locals = int32(textstksiz)
if autoffset < liblink.StackSmall && !(p.From.Scale&liblink.NOSPLIT != 0) {
for q = p; q != nil; q = q.Link {
if q.As == ACALL {
goto noleaf
}
if (q.As == ADUFFCOPY || q.As == ADUFFZERO) && autoffset >= liblink.StackSmall-8 {
goto noleaf
}
}
p.From.Scale |= liblink.NOSPLIT
noleaf:
}
q = nil
if !(p.From.Scale&liblink.NOSPLIT != 0) || (p.From.Scale&liblink.WRAPPER != 0) {
p = liblink.Appendp(ctxt, p)
p = load_g_cx(ctxt, p) // load g into CX
}
if !(cursym.Text.From.Scale&liblink.NOSPLIT != 0) {
p = stacksplit(ctxt, p, autoffset, int32(textarg), bool2int(!(cursym.Text.From.Scale&liblink.NEEDCTXT != 0)), &q) // emit split check
}
if autoffset != 0 {
if autoffset%int32(ctxt.Arch.Regsize) != 0 {
ctxt.Diag("unaligned stack size %d", autoffset)
}
p = liblink.Appendp(ctxt, p)
p.As = AADJSP
p.From.Type_ = D_CONST
p.From.Offset = int64(autoffset)
p.Spadj = autoffset
} else {
// zero-byte stack adjustment.
// Insert a fake non-zero adjustment so that stkcheck can
// recognize the end of the stack-splitting prolog.
p = liblink.Appendp(ctxt, p)
p.As = ANOP
p.Spadj = int32(-ctxt.Arch.Ptrsize)
p = liblink.Appendp(ctxt, p)
p.As = ANOP
p.Spadj = int32(ctxt.Arch.Ptrsize)
}
if q != nil {
q.Pcond = p
}
deltasp = autoffset
if cursym.Text.From.Scale&liblink.WRAPPER != 0 {
// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
//
// MOVQ g_panic(CX), BX
// TESTQ BX, BX
// JEQ end
// LEAQ (autoffset+8)(SP), DI
// CMPQ panic_argp(BX), DI
// JNE end
// MOVQ SP, panic_argp(BX)
// end:
// NOP
//
// The NOP is needed to give the jumps somewhere to land.
// It is a liblink NOP, not an x86 NOP: it encodes to 0 instruction bytes.
p = liblink.Appendp(ctxt, p)
p.As = AMOVQ
p.From.Type_ = D_INDIR + D_CX
p.From.Offset = 4 * int64(ctxt.Arch.Ptrsize) // G.panic
p.To.Type_ = D_BX
if ctxt.Headtype == liblink.Hnacl {
p.As = AMOVL
p.From.Type_ = D_INDIR + D_R15
p.From.Scale = 1
p.From.Index = D_CX
}
p = liblink.Appendp(ctxt, p)
p.As = ATESTQ
p.From.Type_ = D_BX
p.To.Type_ = D_BX
if ctxt.Headtype == liblink.Hnacl {
p.As = ATESTL
}
p = liblink.Appendp(ctxt, p)
p.As = AJEQ
p.To.Type_ = D_BRANCH
p1 = p
p = liblink.Appendp(ctxt, p)
p.As = ALEAQ
p.From.Type_ = D_INDIR + D_SP
p.From.Offset = int64(autoffset) + 8
p.To.Type_ = D_DI
if ctxt.Headtype == liblink.Hnacl {
p.As = ALEAL
}
p = liblink.Appendp(ctxt, p)
p.As = ACMPQ
p.From.Type_ = D_INDIR + D_BX
p.From.Offset = 0 // Panic.argp
p.To.Type_ = D_DI
if ctxt.Headtype == liblink.Hnacl {
p.As = ACMPL
p.From.Type_ = D_INDIR + D_R15
p.From.Scale = 1
p.From.Index = D_BX
}
p = liblink.Appendp(ctxt, p)
p.As = AJNE
p.To.Type_ = D_BRANCH
p2 = p
p = liblink.Appendp(ctxt, p)
p.As = AMOVQ
p.From.Type_ = D_SP
p.To.Type_ = D_INDIR + D_BX
p.To.Offset = 0 // Panic.argp
if ctxt.Headtype == liblink.Hnacl {
p.As = AMOVL
p.To.Type_ = D_INDIR + D_R15
p.To.Scale = 1
p.To.Index = D_BX
}
p = liblink.Appendp(ctxt, p)
p.As = ANOP
p1.Pcond = p
p2.Pcond = p
}
if ctxt.Debugzerostack != 0 && autoffset != 0 && !(cursym.Text.From.Scale&liblink.NOSPLIT != 0) {
// 6l -Z means zero the stack frame on entry.
// This slows down function calls but can help avoid
// false positives in garbage collection.
p = liblink.Appendp(ctxt, p)
p.As = AMOVQ
p.From.Type_ = D_SP
p.To.Type_ = D_DI
p = liblink.Appendp(ctxt, p)
p.As = AMOVQ
p.From.Type_ = D_CONST
p.From.Offset = int64(autoffset) / 8
p.To.Type_ = D_CX
p = liblink.Appendp(ctxt, p)
p.As = AMOVQ
p.From.Type_ = D_CONST
p.From.Offset = 0
p.To.Type_ = D_AX
p = liblink.Appendp(ctxt, p)
p.As = AREP
p = liblink.Appendp(ctxt, p)
p.As = ASTOSQ
}
for ; p != nil; p = p.Link {
pcsize = int(p.Mode) / 8
a = int(p.From.Type_)
if a == D_AUTO {
p.From.Offset += int64(deltasp)
}
if a == D_PARAM {
p.From.Offset += int64(deltasp) + int64(pcsize)
}
a = int(p.To.Type_)
if a == D_AUTO {
p.To.Offset += int64(deltasp)
}
if a == D_PARAM {
p.To.Offset += int64(deltasp) + int64(pcsize)
}
switch p.As {
default:
continue
case APUSHL,
APUSHFL:
deltasp += 4
p.Spadj = 4
continue
case APUSHQ,
APUSHFQ:
deltasp += 8
p.Spadj = 8
continue
case APUSHW,
APUSHFW:
deltasp += 2
p.Spadj = 2
continue
case APOPL,
APOPFL:
deltasp -= 4
p.Spadj = -4
continue
case APOPQ,
APOPFQ:
deltasp -= 8
p.Spadj = -8
continue
case APOPW,
APOPFW:
deltasp -= 2
p.Spadj = -2
continue
case ARET:
break
}
if autoffset != deltasp {
ctxt.Diag("unbalanced PUSH/POP")
}
if autoffset != 0 {
p.As = AADJSP
p.From.Type_ = D_CONST
p.From.Offset = int64(-autoffset)
p.Spadj = -autoffset
p = liblink.Appendp(ctxt, p)
p.As = ARET
// If there are instructions following
// this ARET, they come from a branch
// with the same stackframe, so undo
// the cleanup.
p.Spadj = +autoffset
}
if p.To.Sym != nil { // retjmp
p.As = AJMP
}
}
}
func indir_cx(ctxt *liblink.Link, a *liblink.Addr) {
if ctxt.Headtype == liblink.Hnacl {
a.Type_ = D_INDIR + D_R15
a.Index = D_CX
a.Scale = 1
return
}
a.Type_ = D_INDIR + D_CX
}
// Append code to p to load g into cx.
// Overwrites p with the first instruction (no first appendp).
// Overwriting p is unusual but it lets use this in both the
// prologue (caller must call appendp first) and in the epilogue.
// Returns last new instruction.
func load_g_cx(ctxt *liblink.Link, p *liblink.Prog) *liblink.Prog {
var next *liblink.Prog
p.As = AMOVQ
if ctxt.Arch.Ptrsize == 4 {
p.As = AMOVL
}
p.From.Type_ = D_INDIR + D_TLS
p.From.Offset = 0
p.To.Type_ = D_CX
next = p.Link
progedit(ctxt, p)
for p.Link != next {
p = p.Link
}
if p.From.Index == D_TLS {
p.From.Scale = 2
}
return p
}
// Append code to p to check for stack split.
// Appends to (does not overwrite) p.
// Assumes g is in CX.
// Returns last new instruction.
// On return, *jmpok is the instruction that should jump
// to the stack frame allocation if no split is needed.
func stacksplit(ctxt *liblink.Link, p *liblink.Prog, framesize int32, textarg int32, noctxt int, jmpok **liblink.Prog) *liblink.Prog {
var q *liblink.Prog
var q1 *liblink.Prog
var cmp int
var lea int
var mov int
var sub int
cmp = ACMPQ
lea = ALEAQ
mov = AMOVQ
sub = ASUBQ
if ctxt.Headtype == liblink.Hnacl {
cmp = ACMPL
lea = ALEAL
mov = AMOVL
sub = ASUBL
}
q1 = nil
if framesize <= liblink.StackSmall {
// small stack: SP <= stackguard
// CMPQ SP, stackguard
p = liblink.Appendp(ctxt, p)
p.As = int16(cmp)
p.From.Type_ = D_SP
indir_cx(ctxt, &p.To)
p.To.Offset = 2 * int64(ctxt.Arch.Ptrsize) // G.stackguard0
if ctxt.Cursym.Cfunc != 0 {
p.To.Offset = 3 * int64(ctxt.Arch.Ptrsize) // G.stackguard1
}
} else if framesize <= liblink.StackBig {
// large stack: SP-framesize <= stackguard-StackSmall
// LEAQ -xxx(SP), AX
// CMPQ AX, stackguard
p = liblink.Appendp(ctxt, p)
p.As = int16(lea)
p.From.Type_ = D_INDIR + D_SP
p.From.Offset = -(int64(framesize) - liblink.StackSmall)
p.To.Type_ = D_AX
p = liblink.Appendp(ctxt, p)
p.As = int16(cmp)
p.From.Type_ = D_AX
indir_cx(ctxt, &p.To)
p.To.Offset = 2 * int64(ctxt.Arch.Ptrsize) // G.stackguard0
if ctxt.Cursym.Cfunc != 0 {
p.To.Offset = 3 * int64(ctxt.Arch.Ptrsize) // G.stackguard1
}
} else {
// Such a large stack we need to protect against wraparound.
// If SP is close to zero:
// SP-stackguard+StackGuard <= framesize + (StackGuard-StackSmall)
// The +StackGuard on both sides is required to keep the left side positive:
// SP is allowed to be slightly below stackguard. See stack.h.
//
// Preemption sets stackguard to StackPreempt, a very large value.
// That breaks the math above, so we have to check for that explicitly.
// MOVQ stackguard, CX
// CMPQ CX, $StackPreempt
// JEQ label-of-call-to-morestack
// LEAQ StackGuard(SP), AX
// SUBQ CX, AX
// CMPQ AX, $(framesize+(StackGuard-StackSmall))
p = liblink.Appendp(ctxt, p)
p.As = int16(mov)
indir_cx(ctxt, &p.From)
p.From.Offset = 2 * int64(ctxt.Arch.Ptrsize) // G.stackguard0
if ctxt.Cursym.Cfunc != 0 {
p.From.Offset = 3 * int64(ctxt.Arch.Ptrsize) // G.stackguard1
}
p.To.Type_ = D_SI
p = liblink.Appendp(ctxt, p)
p.As = int16(cmp)
p.From.Type_ = D_SI
p.To.Type_ = D_CONST
p.To.Offset = liblink.StackPreempt
p = liblink.Appendp(ctxt, p)
p.As = AJEQ
p.To.Type_ = D_BRANCH
q1 = p
p = liblink.Appendp(ctxt, p)
p.As = int16(lea)
p.From.Type_ = D_INDIR + D_SP
p.From.Offset = liblink.StackGuard
p.To.Type_ = D_AX
p = liblink.Appendp(ctxt, p)
p.As = int16(sub)
p.From.Type_ = D_SI
p.To.Type_ = D_AX
p = liblink.Appendp(ctxt, p)
p.As = int16(cmp)
p.From.Type_ = D_AX
p.To.Type_ = D_CONST
p.To.Offset = int64(framesize) + (liblink.StackGuard - liblink.StackSmall)
}
// common
p = liblink.Appendp(ctxt, p)
p.As = AJHI
p.To.Type_ = D_BRANCH
q = p
p = liblink.Appendp(ctxt, p)
p.As = ACALL
p.To.Type_ = D_BRANCH
if ctxt.Cursym.Cfunc != 0 {
p.To.Sym = liblink.Linklookup(ctxt, "runtime.morestackc", 0)
} else {
p.To.Sym = ctxt.Symmorestack[noctxt]
}
p = liblink.Appendp(ctxt, p)
p.As = AJMP
p.To.Type_ = D_BRANCH
p.Pcond = ctxt.Cursym.Text.Link
if q != nil {
q.Pcond = p.Link
}
if q1 != nil {
q1.Pcond = q.Link
}
*jmpok = q
return p
}
func follow(ctxt *liblink.Link, s *liblink.LSym) {
var firstp *liblink.Prog
var lastp *liblink.Prog
ctxt.Cursym = s
firstp = ctxt.Arch.Prg()
lastp = firstp
xfol(ctxt, s.Text, &lastp)
lastp.Link = nil
s.Text = firstp.Link
}
func nofollow(a int) int {
switch a {
case AJMP,
ARET,
AIRETL,
AIRETQ,
AIRETW,
ARETFL,
ARETFQ,
ARETFW,
AUNDEF:
return 1
}
return 0
}
func pushpop(a int) int {
switch a {
case APUSHL,
APUSHFL,
APUSHQ,
APUSHFQ,
APUSHW,
APUSHFW,
APOPL,
APOPFL,
APOPQ,
APOPFQ,
APOPW,
APOPFW:
return 1
}
return 0
}
func relinv(a int) int {
switch a {
case AJEQ:
return AJNE
case AJNE:
return AJEQ
case AJLE:
return AJGT
case AJLS:
return AJHI
case AJLT:
return AJGE
case AJMI:
return AJPL
case AJGE:
return AJLT
case AJPL:
return AJMI
case AJGT:
return AJLE
case AJHI:
return AJLS
case AJCS:
return AJCC
case AJCC:
return AJCS
case AJPS:
return AJPC
case AJPC:
return AJPS
case AJOS:
return AJOC
case AJOC:
return AJOS
}
log.Fatalf("unknown relation: %s", anames6[a])
return 0
}
func xfol(ctxt *liblink.Link, p *liblink.Prog, last **liblink.Prog) {
var q *liblink.Prog
var i int
var a int
loop:
if p == nil {
return
}
if p.As == AJMP {
q = p.Pcond
if q != nil && q.As != ATEXT {
/* mark instruction as done and continue layout at target of jump */
p.Mark = 1
p = q
if p.Mark == 0 {
goto loop
}
}
}
if p.Mark != 0 {
/*
* p goes here, but already used it elsewhere.
* copy up to 4 instructions or else branch to other copy.
*/
i = 0
q = p
for ; i < 4; (func() { i++; q = q.Link })() {
if q == nil {
break
}
if q == *last {
break
}
a = int(q.As)
if a == ANOP {
i--
continue
}
if nofollow(a) != 0 || pushpop(a) != 0 {
break // NOTE(rsc): arm does goto copy
}
if q.Pcond == nil || q.Pcond.Mark != 0 {
continue
}
if a == ACALL || a == ALOOP {
continue
}
for {
if p.As == ANOP {
p = p.Link
continue
}
q = liblink.Copyp(ctxt, p)
p = p.Link
q.Mark = 1
(*last).Link = q
*last = q
if int(q.As) != a || q.Pcond == nil || q.Pcond.Mark != 0 {
continue
}
q.As = int16(relinv(int(q.As)))
p = q.Pcond
q.Pcond = q.Link
q.Link = p
xfol(ctxt, q.Link, last)
p = q.Link
if p.Mark != 0 {
return
}
goto loop
/* */
}
}
q = ctxt.Arch.Prg()
q.As = AJMP
q.Lineno = p.Lineno
q.To.Type_ = D_BRANCH
q.To.Offset = p.Pc
q.Pcond = p
p = q
}
/* emit p */
p.Mark = 1
(*last).Link = p
*last = p
a = int(p.As)
/* continue loop with what comes after p */
if nofollow(a) != 0 {
return
}
if p.Pcond != nil && a != ACALL {
/*
* some kind of conditional branch.
* recurse to follow one path.
* continue loop on the other.
*/
q = liblink.Brchain(ctxt, p.Pcond)
if q != nil {
p.Pcond = q
}
q = liblink.Brchain(ctxt, p.Link)
if q != nil {
p.Link = q
}
if p.From.Type_ == D_CONST {
if p.From.Offset == 1 {
/*
* expect conditional jump to be taken.
* rewrite so that's the fall-through case.
*/
p.As = int16(relinv(a))
q = p.Link
p.Link = p.Pcond
p.Pcond = q
}
} else {
q = p.Link
if q.Mark != 0 {
if a != ALOOP {
p.As = int16(relinv(a))
p.Link = p.Pcond
p.Pcond = q
}
}
}
xfol(ctxt, p.Link, last)
if p.Pcond.Mark != 0 {
return
}
p = p.Pcond
goto loop
}
p = p.Link
goto loop
}
func prg() *liblink.Prog {
var p *liblink.Prog
p = new(liblink.Prog)
*p = zprg
return p
}
var Linkamd64 = liblink.LinkArch{
ByteOrder: binary.LittleEndian,
Pconv: Pconv,
Name: "amd64",
Thechar: '6',
Endian: liblink.LittleEndian,
Addstacksplit: addstacksplit,
Assemble: span6,
Datasize: datasize,
Follow: follow,
Iscall: iscall,
Isdata: isdata,
Prg: prg,
Progedit: progedit,
Settextflag: settextflag,
Symtype: symtype,
Textflag: textflag,
Minlc: 1,
Ptrsize: 8,
Regsize: 8,
D_ADDR: D_ADDR,
D_AUTO: D_AUTO,
D_BRANCH: D_BRANCH,
D_CONST: D_CONST,
D_EXTERN: D_EXTERN,
D_FCONST: D_FCONST,
D_NONE: D_NONE,
D_PARAM: D_PARAM,
D_SCONST: D_SCONST,
D_STATIC: D_STATIC,
ACALL: ACALL,
ADATA: ADATA,
AEND: AEND,
AFUNCDATA: AFUNCDATA,
AGLOBL: AGLOBL,
AJMP: AJMP,
ANOP: ANOP,
APCDATA: APCDATA,
ARET: ARET,
ATEXT: ATEXT,
ATYPE: ATYPE,
AUSEFIELD: AUSEFIELD,
}
var Linkamd64p32 = liblink.LinkArch{
ByteOrder: binary.LittleEndian,
Pconv: Pconv,
Name: "amd64p32",
Thechar: '6',
Endian: liblink.LittleEndian,
Addstacksplit: addstacksplit,
Assemble: span6,
Datasize: datasize,
Follow: follow,
Iscall: iscall,
Isdata: isdata,
Prg: prg,
Progedit: progedit,
Settextflag: settextflag,
Symtype: symtype,
Textflag: textflag,
Minlc: 1,
Ptrsize: 4,
Regsize: 8,
D_ADDR: D_ADDR,
D_AUTO: D_AUTO,
D_BRANCH: D_BRANCH,
D_CONST: D_CONST,
D_EXTERN: D_EXTERN,
D_FCONST: D_FCONST,
D_NONE: D_NONE,
D_PARAM: D_PARAM,
D_SCONST: D_SCONST,
D_STATIC: D_STATIC,
ACALL: ACALL,
ADATA: ADATA,
AEND: AEND,
AFUNCDATA: AFUNCDATA,
AGLOBL: AGLOBL,
AJMP: AJMP,
ANOP: ANOP,
APCDATA: APCDATA,
ARET: ARET,
ATEXT: ATEXT,
ATYPE: ATYPE,
AUSEFIELD: AUSEFIELD,
}