コード例 #1
0
ファイル: obj5.go プロジェクト: rsc/tmp
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
		}
	}
}
コード例 #2
0
ファイル: main.go プロジェクト: rsc/tmp
func input() {
	args := flag.Args()
	ctxt = liblink.Linknew(arch)
	ctxt.Debugasm = 1
	ctxt.Bso = liblink.Binitw(os.Stdout)
	defer liblink.Bflush(ctxt.Bso)
	ctxt.Diag = log.Fatalf
	f, err := os.Open(args[0])
	if err != nil {
		log.Fatal(err)
	}

	b := bufio.NewReaderSize(f, 1<<20)
	if rdstring(b) != "ctxt" {
		log.Fatal("invalid input - missing ctxt")
	}
	name := rdstring(b)
	if name != ctxt.Arch.Name {
		log.Fatalf("bad arch %s - want %s", name, ctxt.Arch.Name)
	}

	ctxt.Goarm = int32(rdint(b))
	ctxt.Debugasm = int32(rdint(b))
	ctxt.Trimpath = rdstring(b)
	ctxt.Plist = rdplist(b)
	ctxt.Plast = rdplist(b)
	ctxt.Hist = rdhist(b)
	ctxt.Ehist = rdhist(b)
	for {
		i := rdint(b)
		if i < 0 {
			break
		}
		hashed[rdsym(b)] = true
	}
	last := "ctxt"

Loop:
	for {
		s := rdstring(b)
		switch s {
		default:
			log.Fatalf("unexpected input after %s: %v", s, last)
		case "end":
			break Loop
		case "plist":
			readplist(b, rdplist(b))
		case "sym":
			readsym(b, rdsym(b))
		case "prog":
			readprog(b, rdprog(b))
		case "hist":
			readhist(b, rdhist(b))
		}
		last = s
	}

	if len(undef) > 0 {
		panic("missing definitions")
	}

	ctxt.Hash = make(map[liblink.NameVers]*liblink.LSym)
	for s := range hashed {
		if s == nil {
			continue
		}
		ctxt.Hash[liblink.NameVers{s.Name, int(s.Version)}] = s
	}

	var buf bytes.Buffer
	obuf := liblink.Binitw(&buf)
	liblink.Writeobjdirect(ctxt, obuf)
	liblink.Bflush(obuf)

	data, err := ioutil.ReadFile(args[1])
	if err != nil {
		log.Fatal(err)
	}

	offset, err := strconv.Atoi(args[2])
	if err != nil {
		log.Fatalf("bad offset: %v", err)
	}
	if offset > len(data) {
		log.Fatalf("offset too large: %v > %v", offset, len(data))
	}

	old := data[offset:]
	if len(old) > 0 && !bytes.Equal(old, buf.Bytes()) {
		out := strings.TrimSuffix(args[0], ".in") + ".out"
		if err := ioutil.WriteFile(out, append(data[:offset:offset], buf.Bytes()...), 0666); err != nil {
			log.Fatal(err)
		}
		log.Fatalf("goliblink produced different output:\n\toriginal: %s\n\tgoliblink: %s", args[1], out)
	}

	if len(old) == 0 {
		data = append(data, buf.Bytes()...)
		if err := ioutil.WriteFile(args[1], data, 0666); err != nil {
			log.Fatal(err)
		}
	}
}
コード例 #3
0
ファイル: obj9.go プロジェクト: rsc/tmp
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
		}
	}
}