func readsym(b *bufio.Reader, s *liblink.LSym) {
if !undef[s] {
panic("double-def")
}
delete(undef, s)
s.Name = rdstring(b)
s.Extname = rdstring(b)
s.Type_ = int16(rdint(b))
s.Version = int16(rdint(b))
s.Dupok = uint8(rdint(b))
s.External = uint8(rdint(b))
s.Nosplit = uint8(rdint(b))
s.Reachable = uint8(rdint(b))
s.Cgoexport = uint8(rdint(b))
s.Special = uint8(rdint(b))
s.Stkcheck = uint8(rdint(b))
s.Hide = uint8(rdint(b))
s.Leaf = uint8(rdint(b))
s.Fnptr = uint8(rdint(b))
s.Seenglobl = uint8(rdint(b))
s.Onlist = uint8(rdint(b))
s.Symid = int16(rdint(b))
s.Dynid = int32(rdint(b))
s.Sig = int32(rdint(b))
s.Plt = int32(rdint(b))
s.Got = int32(rdint(b))
s.Align = int32(rdint(b))
s.Elfsym = int32(rdint(b))
s.Args = int32(rdint(b))
s.Locals = int32(rdint(b))
s.Value = rdint(b)
s.Size = rdint(b)
hashed[rdsym(b)] = true
s.Allsym = rdsym(b)
s.Next = rdsym(b)
s.Sub = rdsym(b)
s.Outer = rdsym(b)
s.Gotype = rdsym(b)
s.Reachparent = rdsym(b)
s.Queue = rdsym(b)
s.File = rdstring(b)
s.Dynimplib = rdstring(b)
s.Dynimpvers = rdstring(b)
s.Text = rdprog(b)
s.Etext = rdprog(b)
n := int(rdint(b))
if n > 0 {
s.P = make([]byte, n)
io.ReadFull(b, s.P)
}
s.R = make([]liblink.Reloc, int(rdint(b)))
for i := range s.R {
r := &s.R[i]
r.Off = int32(rdint(b))
r.Siz = uint8(rdint(b))
r.Done = uint8(rdint(b))
r.Type_ = int32(rdint(b))
r.Add = rdint(b)
r.Xadd = rdint(b)
r.Sym = rdsym(b)
r.Xsym = rdsym(b)
}
}
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 q1 *liblink.Prog
var o int
var mov int
var aoffset int
var textstksiz int64
var textarg int64
var autosize int32
if ctxt.Symmorestack[0] == nil {
ctxt.Symmorestack[0] = liblink.Linklookup(ctxt, "runtime.morestack", 0)
ctxt.Symmorestack[1] = liblink.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
}
// TODO(minux): add morestack short-cuts with small fixed frame-size.
ctxt.Cursym = cursym
if cursym.Text == nil || cursym.Text.Link == nil {
return
}
p = cursym.Text
parsetextconst(p.To.Offset, &textstksiz, &textarg)
cursym.Args = int32(p.To.Offset >> 32)
cursym.Locals = int32(textstksiz)
/*
* find leaf subroutines
* strip NOPs
* expand RET
* expand BECOME pseudo
*/
if ctxt.Debugvlog != 0 {
fmt.Fprintf(ctxt.Bso, "%5.2f noops\n", liblink.Cputime())
}
liblink.Bflush(ctxt.Bso)
q = nil
for p = cursym.Text; p != nil; p = p.Link {
switch p.As {
/* too hard, just leave alone */
case ATEXT:
q = p
p.Mark |= LABEL | LEAF | SYNC
if p.Link != nil {
p.Link.Mark |= LABEL
}
case ANOR:
q = p
if p.To.Type_ == D_REG {
if p.To.Reg == REGZERO {
p.Mark |= LABEL | SYNC
}
}
case ALWAR,
ASTWCCC,
AECIWX,
AECOWX,
AEIEIO,
AICBI,
AISYNC,
ATLBIE,
ATLBIEL,
ASLBIA,
ASLBIE,
ASLBMFEE,
ASLBMFEV,
ASLBMTE,
ADCBF,
ADCBI,
ADCBST,
ADCBT,
ADCBTST,
ADCBZ,
ASYNC,
ATLBSYNC,
APTESYNC,
ATW,
AWORD,
ARFI,
ARFCI,
ARFID,
AHRFID:
q = p
p.Mark |= LABEL | SYNC
continue
case AMOVW,
AMOVWZ,
AMOVD:
q = p
switch p.From.Type_ {
case D_MSR,
D_SPR,
D_FPSCR,
D_CREG,
D_DCR:
p.Mark |= LABEL | SYNC
}
switch p.To.Type_ {
case D_MSR,
D_SPR,
D_FPSCR,
D_CREG,
D_DCR:
p.Mark |= LABEL | SYNC
}
continue
case AFABS,
AFABSCC,
AFADD,
AFADDCC,
AFCTIW,
AFCTIWCC,
AFCTIWZ,
AFCTIWZCC,
AFDIV,
AFDIVCC,
AFMADD,
AFMADDCC,
AFMOVD,
AFMOVDU,
/* case AFMOVDS: */
AFMOVS,
AFMOVSU,
/* case AFMOVSD: */
AFMSUB,
AFMSUBCC,
AFMUL,
AFMULCC,
AFNABS,
AFNABSCC,
AFNEG,
AFNEGCC,
AFNMADD,
AFNMADDCC,
AFNMSUB,
AFNMSUBCC,
AFRSP,
AFRSPCC,
AFSUB,
AFSUBCC:
q = p
p.Mark |= FLOAT
continue
case ABL,
ABCL,
ADUFFZERO,
ADUFFCOPY:
cursym.Text.Mark &^= LEAF
fallthrough
case ABC,
ABEQ,
ABGE,
ABGT,
ABLE,
ABLT,
ABNE,
ABR,
ABVC,
ABVS:
p.Mark |= BRANCH
q = p
q1 = p.Pcond
if q1 != nil {
for q1.As == ANOP {
q1 = q1.Link
p.Pcond = q1
}
if !(q1.Mark&LEAF != 0) {
q1.Mark |= LABEL
}
} else {
p.Mark |= LABEL
}
q1 = p.Link
if q1 != nil {
q1.Mark |= LABEL
}
continue
case AFCMPO,
AFCMPU:
q = p
p.Mark |= FCMP | FLOAT
continue
case ARETURN:
q = p
if p.Link != nil {
p.Link.Mark |= LABEL
}
continue
case ANOP:
q1 = p.Link
q.Link = q1 /* q is non-nop */
q1.Mark |= p.Mark
continue
default:
q = p
continue
}
}
autosize = 0
for p = cursym.Text; p != nil; p = p.Link {
o = int(p.As)
switch o {
case ATEXT:
mov = AMOVD
aoffset = 0
autosize = int32(textstksiz + 8)
if (p.Mark&LEAF != 0) && autosize <= 8 {
autosize = 0
} else if autosize&4 != 0 {
autosize += 4
}
p.To.Offset = int64(uint64(p.To.Offset)&(0xffffffff<<32) | uint64(uint32(autosize-8)))
if !(p.Reg&liblink.NOSPLIT != 0) {
p = stacksplit(ctxt, p, autosize, bool2int(!(cursym.Text.Reg&liblink.NEEDCTXT != 0))) // emit split check
}
q = p
if autosize != 0 {
/* use MOVDU to adjust R1 when saving R31, if autosize is small */
if !(cursym.Text.Mark&LEAF != 0) && autosize >= -BIG && autosize <= BIG {
mov = AMOVDU
aoffset = int(-autosize)
} else {
q = liblink.Appendp(ctxt, p)
q.As = AADD
q.Lineno = p.Lineno
q.From.Type_ = D_CONST
q.From.Offset = int64(-autosize)
q.To.Type_ = D_REG
q.To.Reg = REGSP
q.Spadj = +autosize
}
} else if !(cursym.Text.Mark&LEAF != 0) {
if ctxt.Debugvlog != 0 {
fmt.Fprintf(ctxt.Bso, "save suppressed in: %s\n", cursym.Name)
liblink.Bflush(ctxt.Bso)
}
cursym.Text.Mark |= LEAF
}
if cursym.Text.Mark&LEAF != 0 {
cursym.Leaf = 1
break
}
q = liblink.Appendp(ctxt, q)
q.As = AMOVD
q.Lineno = p.Lineno
q.From.Type_ = D_SPR
q.From.Offset = D_LR
q.To.Type_ = D_REG
q.To.Reg = REGTMP
q = liblink.Appendp(ctxt, q)
q.As = int16(mov)
q.Lineno = p.Lineno
q.From.Type_ = D_REG
q.From.Reg = REGTMP
q.To.Type_ = D_OREG
q.To.Offset = int64(aoffset)
q.To.Reg = REGSP
if q.As == AMOVDU {
q.Spadj = int32(-aoffset)
}
if cursym.Text.Reg&liblink.WRAPPER != 0 {
// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
//
// MOVD g_panic(g), R3
// CMP R0, R3
// BEQ end
// MOVD panic_argp(R3), R4
// ADD $(autosize+8), R1, R5
// CMP R4, R5
// BNE end
// ADD $8, R1, R6
// MOVD R6, panic_argp(R3)
// end:
// NOP
//
// The NOP is needed to give the jumps somewhere to land.
// It is a liblink NOP, not a ppc64 NOP: it encodes to 0 instruction bytes.
q = liblink.Appendp(ctxt, q)
q.As = AMOVD
q.From.Type_ = D_OREG
q.From.Reg = REGG
q.From.Offset = 4 * int64(ctxt.Arch.Ptrsize) // G.panic
q.To.Type_ = D_REG
q.To.Reg = 3
q = liblink.Appendp(ctxt, q)
q.As = ACMP
q.From.Type_ = D_REG
q.From.Reg = 0
q.To.Type_ = D_REG
q.To.Reg = 3
q = liblink.Appendp(ctxt, q)
q.As = ABEQ
q.To.Type_ = D_BRANCH
p1 = q
q = liblink.Appendp(ctxt, q)
q.As = AMOVD
q.From.Type_ = D_OREG
q.From.Reg = 3
q.From.Offset = 0 // Panic.argp
q.To.Type_ = D_REG
q.To.Reg = 4
q = liblink.Appendp(ctxt, q)
q.As = AADD
q.From.Type_ = D_CONST
q.From.Offset = int64(autosize) + 8
q.Reg = REGSP
q.To.Type_ = D_REG
q.To.Reg = 5
q = liblink.Appendp(ctxt, q)
q.As = ACMP
q.From.Type_ = D_REG
q.From.Reg = 4
q.To.Type_ = D_REG
q.To.Reg = 5
q = liblink.Appendp(ctxt, q)
q.As = ABNE
q.To.Type_ = D_BRANCH
p2 = q
q = liblink.Appendp(ctxt, q)
q.As = AADD
q.From.Type_ = D_CONST
q.From.Offset = 8
q.Reg = REGSP
q.To.Type_ = D_REG
q.To.Reg = 6
q = liblink.Appendp(ctxt, q)
q.As = AMOVD
q.From.Type_ = D_REG
q.From.Reg = 6
q.To.Type_ = D_OREG
q.To.Reg = 3
q.To.Offset = 0 // Panic.argp
q = liblink.Appendp(ctxt, q)
q.As = ANOP
p1.Pcond = q
p2.Pcond = q
}
case ARETURN:
if p.From.Type_ == D_CONST {
ctxt.Diag("using BECOME (%P) is not supported!", p)
break
}
if p.To.Sym != nil { // retjmp
p.As = ABR
p.To.Type_ = D_BRANCH
break
}
if cursym.Text.Mark&LEAF != 0 {
if !(autosize != 0) {
p.As = ABR
p.From = zprg.From
p.To.Type_ = D_SPR
p.To.Offset = D_LR
p.Mark |= BRANCH
break
}
p.As = AADD
p.From.Type_ = D_CONST
p.From.Offset = int64(autosize)
p.To.Type_ = D_REG
p.To.Reg = REGSP
p.Spadj = -autosize
q = ctxt.Arch.Prg()
q.As = ABR
q.Lineno = p.Lineno
q.To.Type_ = D_SPR
q.To.Offset = D_LR
q.Mark |= BRANCH
q.Spadj = +autosize
q.Link = p.Link
p.Link = q
break
}
p.As = AMOVD
p.From.Type_ = D_OREG
p.From.Offset = 0
p.From.Reg = REGSP
p.To.Type_ = D_REG
p.To.Reg = REGTMP
q = ctxt.Arch.Prg()
q.As = AMOVD
q.Lineno = p.Lineno
q.From.Type_ = D_REG
q.From.Reg = REGTMP
q.To.Type_ = D_SPR
q.To.Offset = D_LR
q.Link = p.Link
p.Link = q
p = q
if false {
// Debug bad returns
q = ctxt.Arch.Prg()
q.As = AMOVD
q.Lineno = p.Lineno
q.From.Type_ = D_OREG
q.From.Offset = 0
q.From.Reg = REGTMP
q.To.Type_ = D_REG
q.To.Reg = REGTMP
q.Link = p.Link
p.Link = q
p = q
}
if autosize != 0 {
q = ctxt.Arch.Prg()
q.As = AADD
q.Lineno = p.Lineno
q.From.Type_ = D_CONST
q.From.Offset = int64(autosize)
q.To.Type_ = D_REG
q.To.Reg = REGSP
q.Spadj = -autosize
q.Link = p.Link
p.Link = q
}
q1 = ctxt.Arch.Prg()
q1.As = ABR
q1.Lineno = p.Lineno
q1.To.Type_ = D_SPR
q1.To.Offset = D_LR
q1.Mark |= BRANCH
q1.Spadj = +autosize
q1.Link = q.Link
q.Link = q1
case AADD:
if p.To.Type_ == D_REG && p.To.Reg == REGSP && p.From.Type_ == D_CONST {
p.Spadj = int32(-p.From.Offset)
}
break
}
}
}
func addstacksplit(ctxt *liblink.Link, cursym *liblink.LSym) {
var p *liblink.Prog
var pl *liblink.Prog
var p1 *liblink.Prog
var p2 *liblink.Prog
var q *liblink.Prog
var q1 *liblink.Prog
var q2 *liblink.Prog
var o int
var autosize int32
var autoffset int32
autosize = 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)
}
q = nil
ctxt.Cursym = cursym
if cursym.Text == nil || cursym.Text.Link == nil {
return
}
softfloat(ctxt, cursym)
p = cursym.Text
autoffset = int32(p.To.Offset)
if autoffset < 0 {
autoffset = 0
}
cursym.Locals = autoffset
cursym.Args = p.To.Offset2
if ctxt.Debugzerostack != 0 {
if autoffset != 0 && !(p.Reg&liblink.NOSPLIT != 0) {
// MOVW $4(R13), R1
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type_ = D_CONST
p.From.Reg = 13
p.From.Offset = 4
p.To.Type_ = D_REG
p.To.Reg = 1
// MOVW $n(R13), R2
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type_ = D_CONST
p.From.Reg = 13
p.From.Offset = 4 + int64(autoffset)
p.To.Type_ = D_REG
p.To.Reg = 2
// MOVW $0, R3
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type_ = D_CONST
p.From.Offset = 0
p.To.Type_ = D_REG
p.To.Reg = 3
// L:
// MOVW.nil R3, 0(R1) +4
// CMP R1, R2
// BNE L
pl = liblink.Appendp(ctxt, p)
p = pl
p.As = AMOVW
p.From.Type_ = D_REG
p.From.Reg = 3
p.To.Type_ = D_OREG
p.To.Reg = 1
p.To.Offset = 4
p.Scond |= C_PBIT
p = liblink.Appendp(ctxt, p)
p.As = ACMP
p.From.Type_ = D_REG
p.From.Reg = 1
p.Reg = 2
p = liblink.Appendp(ctxt, p)
p.As = ABNE
p.To.Type_ = D_BRANCH
p.Pcond = pl
}
}
/*
* find leaf subroutines
* strip NOPs
* expand RET
* expand BECOME pseudo
*/
for p = cursym.Text; p != nil; p = p.Link {
switch p.As {
case ACASE:
if ctxt.Flag_shared != 0 {
linkcase(p)
}
case ATEXT:
p.Mark |= LEAF
case ARET:
break
case ADIV,
ADIVU,
AMOD,
AMODU:
q = p
if ctxt.Sym_div == nil {
initdiv(ctxt)
}
cursym.Text.Mark &^= LEAF
continue
case ANOP:
q1 = p.Link
q.Link = q1 /* q is non-nop */
if q1 != nil {
q1.Mark |= p.Mark
}
continue
case ABL,
ABX,
ADUFFZERO,
ADUFFCOPY:
cursym.Text.Mark &^= LEAF
fallthrough
case ABCASE,
AB,
ABEQ,
ABNE,
ABCS,
ABHS,
ABCC,
ABLO,
ABMI,
ABPL,
ABVS,
ABVC,
ABHI,
ABLS,
ABGE,
ABLT,
ABGT,
ABLE:
q1 = p.Pcond
if q1 != nil {
for q1.As == ANOP {
q1 = q1.Link
p.Pcond = q1
}
}
break
}
q = p
}
for p = cursym.Text; p != nil; p = p.Link {
o = int(p.As)
switch o {
case ATEXT:
autosize = int32(p.To.Offset + 4)
if autosize <= 4 {
if cursym.Text.Mark&LEAF != 0 {
p.To.Offset = -4
autosize = 0
}
}
if !(autosize != 0) && !(cursym.Text.Mark&LEAF != 0) {
if ctxt.Debugvlog != 0 {
fmt.Fprintf(ctxt.Bso, "save suppressed in: %s\n", cursym.Name)
liblink.Bflush(ctxt.Bso)
}
cursym.Text.Mark |= LEAF
}
if cursym.Text.Mark&LEAF != 0 {
cursym.Leaf = 1
if !(autosize != 0) {
break
}
}
if !(p.Reg&liblink.NOSPLIT != 0) {
p = stacksplit(ctxt, p, autosize, bool2int(!(cursym.Text.Reg&liblink.NEEDCTXT != 0))) // emit split check
}
// MOVW.W R14,$-autosize(SP)
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.Scond |= C_WBIT
p.From.Type_ = D_REG
p.From.Reg = REGLINK
p.To.Type_ = D_OREG
p.To.Offset = int64(-autosize)
p.To.Reg = REGSP
p.Spadj = autosize
if cursym.Text.Reg&liblink.WRAPPER != 0 {
// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
//
// MOVW g_panic(g), R1
// CMP $0, R1
// B.EQ end
// MOVW panic_argp(R1), R2
// ADD $(autosize+4), R13, R3
// CMP R2, R3
// B.NE end
// ADD $4, R13, R4
// MOVW R4, panic_argp(R1)
// end:
// NOP
//
// The NOP is needed to give the jumps somewhere to land.
// It is a liblink NOP, not an ARM NOP: it encodes to 0 instruction bytes.
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type_ = D_OREG
p.From.Reg = REGG
p.From.Offset = 4 * int64(ctxt.Arch.Ptrsize) // G.panic
p.To.Type_ = D_REG
p.To.Reg = 1
p = liblink.Appendp(ctxt, p)
p.As = ACMP
p.From.Type_ = D_CONST
p.From.Offset = 0
p.Reg = 1
p = liblink.Appendp(ctxt, p)
p.As = ABEQ
p.To.Type_ = D_BRANCH
p1 = p
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type_ = D_OREG
p.From.Reg = 1
p.From.Offset = 0 // Panic.argp
p.To.Type_ = D_REG
p.To.Reg = 2
p = liblink.Appendp(ctxt, p)
p.As = AADD
p.From.Type_ = D_CONST
p.From.Offset = int64(autosize) + 4
p.Reg = 13
p.To.Type_ = D_REG
p.To.Reg = 3
p = liblink.Appendp(ctxt, p)
p.As = ACMP
p.From.Type_ = D_REG
p.From.Reg = 2
p.Reg = 3
p = liblink.Appendp(ctxt, p)
p.As = ABNE
p.To.Type_ = D_BRANCH
p2 = p
p = liblink.Appendp(ctxt, p)
p.As = AADD
p.From.Type_ = D_CONST
p.From.Offset = 4
p.Reg = 13
p.To.Type_ = D_REG
p.To.Reg = 4
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.From.Type_ = D_REG
p.From.Reg = 4
p.To.Type_ = D_OREG
p.To.Reg = 1
p.To.Offset = 0 // Panic.argp
p = liblink.Appendp(ctxt, p)
p.As = ANOP
p1.Pcond = p
p2.Pcond = p
}
case ARET:
nocache5(p)
if cursym.Text.Mark&LEAF != 0 {
if !(autosize != 0) {
p.As = AB
p.From = zprg5.From
if p.To.Sym != nil { // retjmp
p.To.Type_ = D_BRANCH
} else {
p.To.Type_ = D_OREG
p.To.Offset = 0
p.To.Reg = REGLINK
}
break
}
}
p.As = AMOVW
p.Scond |= C_PBIT
p.From.Type_ = D_OREG
p.From.Offset = int64(autosize)
p.From.Reg = REGSP
p.To.Type_ = D_REG
p.To.Reg = REGPC
// If there are instructions following
// this ARET, they come from a branch
// with the same stackframe, so no spadj.
if p.To.Sym != nil { // retjmp
p.To.Reg = REGLINK
q2 = liblink.Appendp(ctxt, p)
q2.As = AB
q2.To.Type_ = D_BRANCH
q2.To.Sym = p.To.Sym
p.To.Sym = nil
p = q2
}
case AADD:
if p.From.Type_ == D_CONST && p.From.Reg == NREG && p.To.Type_ == D_REG && p.To.Reg == REGSP {
p.Spadj = int32(-p.From.Offset)
}
case ASUB:
if p.From.Type_ == D_CONST && p.From.Reg == NREG && p.To.Type_ == D_REG && p.To.Reg == REGSP {
p.Spadj = int32(p.From.Offset)
}
case ADIV,
ADIVU,
AMOD,
AMODU:
if ctxt.Debugdivmod != 0 {
break
}
if p.From.Type_ != D_REG {
break
}
if p.To.Type_ != D_REG {
break
}
q1 = p
/* MOV a,4(SP) */
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.Lineno = q1.Lineno
p.From.Type_ = D_REG
p.From.Reg = q1.From.Reg
p.To.Type_ = D_OREG
p.To.Reg = REGSP
p.To.Offset = 4
/* MOV b,REGTMP */
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.Lineno = q1.Lineno
p.From.Type_ = D_REG
p.From.Reg = int8(q1.Reg)
if q1.Reg == NREG {
p.From.Reg = q1.To.Reg
}
p.To.Type_ = D_REG
p.To.Reg = REGTMP
p.To.Offset = 0
/* CALL appropriate */
p = liblink.Appendp(ctxt, p)
p.As = ABL
p.Lineno = q1.Lineno
p.To.Type_ = D_BRANCH
switch o {
case ADIV:
p.To.Sym = ctxt.Sym_div
case ADIVU:
p.To.Sym = ctxt.Sym_divu
case AMOD:
p.To.Sym = ctxt.Sym_mod
case AMODU:
p.To.Sym = ctxt.Sym_modu
break
}
/* MOV REGTMP, b */
p = liblink.Appendp(ctxt, p)
p.As = AMOVW
p.Lineno = q1.Lineno
p.From.Type_ = D_REG
p.From.Reg = REGTMP
p.From.Offset = 0
p.To.Type_ = D_REG
p.To.Reg = q1.To.Reg
/* ADD $8,SP */
p = liblink.Appendp(ctxt, p)
p.As = AADD
p.Lineno = q1.Lineno
p.From.Type_ = D_CONST
p.From.Reg = NREG
p.From.Offset = 8
p.Reg = NREG
p.To.Type_ = D_REG
p.To.Reg = REGSP
p.Spadj = -8
/* Keep saved LR at 0(SP) after SP change. */
/* MOVW 0(SP), REGTMP; MOVW REGTMP, -8!(SP) */
/* TODO: Remove SP adjustments; see issue 6699. */
q1.As = AMOVW
q1.From.Type_ = D_OREG
q1.From.Reg = REGSP
q1.From.Offset = 0
q1.Reg = NREG
q1.To.Type_ = D_REG
q1.To.Reg = REGTMP
/* SUB $8,SP */
q1 = liblink.Appendp(ctxt, q1)
q1.As = AMOVW
q1.From.Type_ = D_REG
q1.From.Reg = REGTMP
q1.Reg = NREG
q1.To.Type_ = D_OREG
q1.To.Reg = REGSP
q1.To.Offset = -8
q1.Scond |= C_WBIT
q1.Spadj = 8
case AMOVW:
if (p.Scond&C_WBIT != 0) && p.To.Type_ == D_OREG && p.To.Reg == REGSP {
p.Spadj = int32(-p.To.Offset)
}
if (p.Scond&C_PBIT != 0) && p.From.Type_ == D_OREG && p.From.Reg == REGSP && p.To.Reg != REGPC {
p.Spadj = int32(-p.From.Offset)
}
if p.From.Type_ == D_CONST && p.From.Reg == REGSP && p.To.Type_ == D_REG && p.To.Reg == REGSP {
p.Spadj = int32(-p.From.Offset)
}
break
}
}
}
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
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
autoffset = int32(p.To.Offset)
if autoffset < 0 {
autoffset = 0
}
cursym.Locals = autoffset
cursym.Args = p.To.Offset2
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, bool2int(!(cursym.Text.From.Scale&liblink.NEEDCTXT != 0)), &q) // emit split check
}
if autoffset != 0 {
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
//
// MOVL g_panic(CX), BX
// TESTL BX, BX
// JEQ end
// LEAL (autoffset+4)(SP), DI
// CMPL panic_argp(BX), DI
// JNE end
// MOVL 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 = AMOVL
p.From.Type_ = D_INDIR + D_CX
p.From.Offset = 4 * int64(ctxt.Arch.Ptrsize) // G.panic
p.To.Type_ = D_BX
p = liblink.Appendp(ctxt, p)
p.As = ATESTL
p.From.Type_ = D_BX
p.To.Type_ = D_BX
p = liblink.Appendp(ctxt, p)
p.As = AJEQ
p.To.Type_ = D_BRANCH
p1 = p
p = liblink.Appendp(ctxt, p)
p.As = ALEAL
p.From.Type_ = D_INDIR + D_SP
p.From.Offset = int64(autoffset) + 4
p.To.Type_ = D_DI
p = liblink.Appendp(ctxt, p)
p.As = ACMPL
p.From.Type_ = D_INDIR + D_BX
p.From.Offset = 0 // Panic.argp
p.To.Type_ = D_DI
p = liblink.Appendp(ctxt, p)
p.As = AJNE
p.To.Type_ = D_BRANCH
p2 = p
p = liblink.Appendp(ctxt, p)
p.As = AMOVL
p.From.Type_ = D_SP
p.To.Type_ = D_INDIR + D_BX
p.To.Offset = 0 // Panic.argp
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) {
// 8l -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 = AMOVL
p.From.Type_ = D_SP
p.To.Type_ = D_DI
p = liblink.Appendp(ctxt, p)
p.As = AMOVL
p.From.Type_ = D_CONST
p.From.Offset = int64(autoffset) / 4
p.To.Type_ = D_CX
p = liblink.Appendp(ctxt, p)
p.As = AMOVL
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 = ASTOSL
}
for ; p != nil; p = p.Link {
a = int(p.From.Type_)
if a == D_AUTO {
p.From.Offset += int64(deltasp)
}
if a == D_PARAM {
p.From.Offset += int64(deltasp) + 4
}
a = int(p.To.Type_)
if a == D_AUTO {
p.To.Offset += int64(deltasp)
}
if a == D_PARAM {
p.To.Offset += int64(deltasp) + 4
}
switch p.As {
default:
continue
case APUSHL,
APUSHFL:
deltasp += 4
p.Spadj = 4
continue
case APUSHW,
APUSHFW:
deltasp += 2
p.Spadj = 2
continue
case APOPL,
APOPFL:
deltasp -= 4
p.Spadj = -4
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
}
}
}