Esempio n. 1
0
File: asm0.go Progetto: ckeyer/gosrc
func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
	o1 := uint32(0)
	o2 := uint32(0)
	o3 := uint32(0)
	o4 := uint32(0)

	switch o.type_ {
	default:
		ctxt.Diag("unknown type %d %v", o.type_)
		prasm(p)

	case 0: /* pseudo ops */
		break

	case 1: /* mov r1,r2 ==> OR r1,r0,r2 */
		o1 = OP_RRR(oprrr(ctxt, AOR), uint32(p.From.Reg), uint32(REGZERO), uint32(p.To.Reg))

	case 2: /* add/sub r1,[r2],r3 */
		r := int(p.Reg)

		if r == 0 {
			r = int(p.To.Reg)
		}
		o1 = OP_RRR(oprrr(ctxt, int(p.As)), uint32(p.From.Reg), uint32(r), uint32(p.To.Reg))

	case 3: /* mov $soreg, r ==> or/add $i,o,r */
		v := regoff(ctxt, &p.From)

		r := int(p.From.Reg)
		if r == 0 {
			r = int(o.param)
		}
		a := AADDVU
		if o.a1 == C_ANDCON {
			a = AOR
		}

		o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(r), uint32(p.To.Reg))

	case 4: /* add $scon,[r1],r2 */
		v := regoff(ctxt, &p.From)

		r := int(p.Reg)
		if r == 0 {
			r = int(p.To.Reg)
		}

		o1 = OP_IRR(opirr(ctxt, int(p.As)), uint32(v), uint32(r), uint32(p.To.Reg))

	case 5: /* syscall */
		o1 = uint32(oprrr(ctxt, int(p.As)))

	case 6: /* beq r1,[r2],sbra */
		v := int32(0)
		if p.Pcond == nil {
			v = int32(-4) >> 2
		} else {
			v = int32(p.Pcond.Pc-p.Pc-4) >> 2
		}
		if (v<<16)>>16 != v {
			ctxt.Diag("short branch too far\n%v", p)
		}
		o1 = OP_IRR(opirr(ctxt, int(p.As)), uint32(v), uint32(p.From.Reg), uint32(p.Reg))
		// for ABFPT and ABFPF only: always fill delay slot with 0
		// see comments in func preprocess for details.
		o2 = 0

	case 7: /* mov r, soreg ==> sw o(r) */
		r := int(p.To.Reg)
		if r == 0 {
			r = int(o.param)
		}
		v := regoff(ctxt, &p.To)
		o1 = OP_IRR(opirr(ctxt, int(p.As)), uint32(v), uint32(r), uint32(p.From.Reg))

	case 8: /* mov soreg, r ==> lw o(r) */
		r := int(p.From.Reg)
		if r == 0 {
			r = int(o.param)
		}
		v := regoff(ctxt, &p.From)
		o1 = OP_IRR(opirr(ctxt, int(p.As)+ALAST), uint32(v), uint32(r), uint32(p.To.Reg))

	case 9: /* sll r1,[r2],r3 */
		r := int(p.Reg)

		if r == 0 {
			r = int(p.To.Reg)
		}
		o1 = OP_RRR(oprrr(ctxt, int(p.As)), uint32(r), uint32(p.From.Reg), uint32(p.To.Reg))

	case 10: /* add $con,[r1],r2 ==> mov $con, t; add t,[r1],r2 */
		v := regoff(ctxt, &p.From)
		a := AOR
		if v < 0 {
			a = AADDU
		}
		o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(0), uint32(REGTMP))
		r := int(p.Reg)
		if r == 0 {
			r = int(p.To.Reg)
		}
		o2 = OP_RRR(oprrr(ctxt, int(p.As)), uint32(REGTMP), uint32(r), uint32(p.To.Reg))

	case 11: /* jmp lbra */
		v := int32(0)
		if aclass(ctxt, &p.To) == C_SBRA && p.To.Sym == nil && p.As == AJMP {
			// use PC-relative branch for short branches
			// BEQ	R0, R0, sbra
			if p.Pcond == nil {
				v = int32(-4) >> 2
			} else {
				v = int32(p.Pcond.Pc-p.Pc-4) >> 2
			}
			if (v<<16)>>16 == v {
				o1 = OP_IRR(opirr(ctxt, ABEQ), uint32(v), uint32(REGZERO), uint32(REGZERO))
				break
			}
		}
		if p.Pcond == nil {
			v = int32(p.Pc) >> 2
		} else {
			v = int32(p.Pcond.Pc) >> 2
		}
		o1 = OP_JMP(opirr(ctxt, int(p.As)), uint32(v))
		if p.To.Sym == nil {
			p.To.Sym = ctxt.Cursym.Text.From.Sym
			p.To.Offset = p.Pcond.Pc
		}
		rel := obj.Addrel(ctxt.Cursym)
		rel.Off = int32(ctxt.Pc)
		rel.Siz = 4
		rel.Sym = p.To.Sym
		rel.Add = p.To.Offset
		if p.As == AJAL {
			rel.Type = obj.R_CALLMIPS
		} else {
			rel.Type = obj.R_JMPMIPS
		}

	case 12: /* movbs r,r */
		v := 16
		if p.As == AMOVB {
			v = 24
		}
		o1 = OP_SRR(opirr(ctxt, ASLL), uint32(v), uint32(p.From.Reg), uint32(p.To.Reg))
		o2 = OP_SRR(opirr(ctxt, ASRA), uint32(v), uint32(p.To.Reg), uint32(p.To.Reg))

	case 13: /* movbu r,r */
		if p.As == AMOVBU {
			o1 = OP_IRR(opirr(ctxt, AAND), uint32(0xff), uint32(p.From.Reg), uint32(p.To.Reg))
		} else {
			o1 = OP_IRR(opirr(ctxt, AAND), uint32(0xffff), uint32(p.From.Reg), uint32(p.To.Reg))
		}

	case 14: /* movwu r,r */
		o1 = OP_SRR(opirr(ctxt, ASLLV+ALAST), uint32(0), uint32(p.From.Reg), uint32(p.To.Reg))
		if p.As == AMOVWU {
			o2 = OP_SRR(opirr(ctxt, ASRLV+ALAST), uint32(0), uint32(p.To.Reg), uint32(p.To.Reg))
		} else {
			o2 = OP_SRR(opirr(ctxt, ASRAV+ALAST), uint32(0), uint32(p.To.Reg), uint32(p.To.Reg))
		}

	case 16: /* sll $c,[r1],r2 */
		v := regoff(ctxt, &p.From)
		r := int(p.Reg)
		if r == 0 {
			r = int(p.To.Reg)
		}

		/* OP_SRR will use only the low 5 bits of the shift value */
		if v >= 32 && vshift(p.As) {
			o1 = OP_SRR(opirr(ctxt, int(p.As)+ALAST), uint32(v-32), uint32(r), uint32(p.To.Reg))
		} else {
			o1 = OP_SRR(opirr(ctxt, int(p.As)), uint32(v), uint32(r), uint32(p.To.Reg))
		}

	case 18: /* jmp [r1],0(r2) */
		r := int(p.Reg)
		if r == 0 {
			r = int(o.param)
		}
		o1 = OP_RRR(oprrr(ctxt, int(p.As)), uint32(0), uint32(p.To.Reg), uint32(r))
		rel := obj.Addrel(ctxt.Cursym)
		rel.Off = int32(ctxt.Pc)
		rel.Siz = 0
		rel.Type = obj.R_CALLIND

	case 19: /* mov $lcon,r ==> lu+or */
		v := regoff(ctxt, &p.From)
		o1 = OP_IRR(opirr(ctxt, ALAST), uint32(v>>16), uint32(REGZERO), uint32(p.To.Reg))
		o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(p.To.Reg), uint32(p.To.Reg))
		if p.From.Sym != nil {
			rel := obj.Addrel(ctxt.Cursym)
			rel.Off = int32(ctxt.Pc)
			rel.Siz = 8
			rel.Sym = p.From.Sym
			rel.Add = p.From.Offset
			rel.Type = obj.R_ADDRMIPS
		}

	case 20: /* mov lo/hi,r */
		a := OP(2, 0) /* mfhi */
		if p.From.Reg == REG_LO {
			a = OP(2, 2) /* mflo */
		}
		o1 = OP_RRR(a, uint32(REGZERO), uint32(REGZERO), uint32(p.To.Reg))

	case 21: /* mov r,lo/hi */
		a := OP(2, 1) /* mthi */
		if p.To.Reg == REG_LO {
			a = OP(2, 3) /* mtlo */
		}
		o1 = OP_RRR(a, uint32(REGZERO), uint32(p.From.Reg), uint32(REGZERO))

	case 22: /* mul r1,r2 */
		o1 = OP_RRR(oprrr(ctxt, int(p.As)), uint32(p.From.Reg), uint32(p.Reg), uint32(REGZERO))

	case 23: /* add $lcon,r1,r2 ==> lu+or+add */
		v := regoff(ctxt, &p.From)
		o1 = OP_IRR(opirr(ctxt, ALAST), uint32(v>>16), uint32(REGZERO), uint32(REGTMP))
		o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(REGTMP), uint32(REGTMP))
		r := int(p.Reg)
		if r == 0 {
			r = int(p.To.Reg)
		}
		o3 = OP_RRR(oprrr(ctxt, int(p.As)), uint32(REGTMP), uint32(r), uint32(p.To.Reg))

	case 24: /* mov $ucon,r ==> lu r */
		v := regoff(ctxt, &p.From)
		o1 = OP_IRR(opirr(ctxt, ALAST), uint32(v>>16), uint32(REGZERO), uint32(p.To.Reg))

	case 25: /* add/and $ucon,[r1],r2 ==> lu $con,t; add t,[r1],r2 */
		v := regoff(ctxt, &p.From)
		o1 = OP_IRR(opirr(ctxt, ALAST), uint32(v>>16), uint32(REGZERO), uint32(REGTMP))
		r := int(p.Reg)
		if r == 0 {
			r = int(p.To.Reg)
		}
		o2 = OP_RRR(oprrr(ctxt, int(p.As)), uint32(REGTMP), uint32(r), uint32(p.To.Reg))

	case 26: /* mov $lsext/auto/oreg,r ==> lu+or+add */
		v := regoff(ctxt, &p.From)
		o1 = OP_IRR(opirr(ctxt, ALAST), uint32(v>>16), uint32(REGZERO), uint32(REGTMP))
		o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(REGTMP), uint32(REGTMP))
		r := int(p.From.Reg)
		if r == 0 {
			r = int(o.param)
		}
		o3 = OP_RRR(oprrr(ctxt, AADDVU), uint32(REGTMP), uint32(r), uint32(p.To.Reg))

	case 27: /* mov [sl]ext/auto/oreg,fr ==> lwc1 o(r) */
		v := regoff(ctxt, &p.From)
		r := int(p.From.Reg)
		if r == 0 {
			r = int(o.param)
		}
		a := AMOVF + ALAST
		if p.As == AMOVD {
			a = AMOVD + ALAST
		}
		switch o.size {
		case 16:
			o1 = OP_IRR(opirr(ctxt, ALAST), uint32(v>>16), uint32(REGZERO), uint32(REGTMP))
			o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(REGTMP), uint32(REGTMP))
			o3 = OP_RRR(opirr(ctxt, AADDVU), uint32(r), uint32(REGTMP), uint32(REGTMP))
			o4 = OP_IRR(opirr(ctxt, a), uint32(0), uint32(r), uint32(p.To.Reg))

		case 4:
			o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(r), uint32(p.To.Reg))
		}

	case 28: /* mov fr,[sl]ext/auto/oreg ==> swc1 o(r) */
		v := regoff(ctxt, &p.To)
		r := int(p.To.Reg)
		if r == 0 {
			r = int(o.param)
		}
		a := AMOVF
		if p.As == AMOVD {
			a = AMOVD
		}
		switch o.size {
		case 16:
			o1 = OP_IRR(opirr(ctxt, ALAST), uint32(v>>16), uint32(REGZERO), uint32(REGTMP))
			o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(REGTMP), uint32(REGTMP))
			o3 = OP_RRR(opirr(ctxt, AADDVU), uint32(r), uint32(REGTMP), uint32(REGTMP))
			o4 = OP_IRR(opirr(ctxt, a), uint32(0), uint32(REGTMP), uint32(p.From.Reg))

		case 4:
			o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(r), uint32(p.From.Reg))
		}

	case 30: /* movw r,fr */
		a := SP(2, 1) | (4 << 21) /* mtc1 */
		o1 = OP_RRR(a, uint32(p.From.Reg), uint32(0), uint32(p.To.Reg))

	case 31: /* movw fr,r */
		a := SP(2, 1) | (0 << 21) /* mtc1 */
		o1 = OP_RRR(a, uint32(p.To.Reg), uint32(0), uint32(p.From.Reg))

	case 32: /* fadd fr1,[fr2],fr3 */
		r := int(p.Reg)
		if r == 0 {
			r = int(p.To.Reg)
		}
		o1 = OP_FRRR(oprrr(ctxt, int(p.As)), uint32(p.From.Reg), uint32(r), uint32(p.To.Reg))

	case 33: /* fabs fr1, fr3 */
		o1 = OP_FRRR(oprrr(ctxt, int(p.As)), uint32(0), uint32(p.From.Reg), uint32(p.To.Reg))

	case 34: /* mov $con,fr ==> or/add $i,t; mov t,fr */
		v := regoff(ctxt, &p.From)
		a := AADDU
		if o.a1 == C_ANDCON {
			a = AOR
		}
		o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(0), uint32(REGTMP))
		o2 = OP_RRR(SP(2, 1)|(4<<21), uint32(REGTMP), uint32(0), uint32(p.To.Reg)) /* mtc1 */

	case 35: /* mov r,lext/auto/oreg ==> sw o(r) */
		v := regoff(ctxt, &p.To)
		r := int(p.To.Reg)
		if r == 0 {
			r = int(o.param)
		}
		o1 = OP_IRR(opirr(ctxt, ALAST), uint32(v>>16), uint32(REGZERO), uint32(REGTMP))
		o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(REGTMP), uint32(REGTMP))
		o3 = OP_RRR(oprrr(ctxt, AADDVU), uint32(r), uint32(REGTMP), uint32(REGTMP))
		o4 = OP_IRR(opirr(ctxt, int(p.As)), uint32(0), uint32(REGTMP), uint32(p.From.Reg))

	case 36: /* mov lext/auto/oreg,r ==> lw o(r30) */
		v := regoff(ctxt, &p.From)
		r := int(p.From.Reg)
		if r == 0 {
			r = int(o.param)
		}
		o1 = OP_IRR(opirr(ctxt, ALAST), uint32(v>>16), uint32(REGZERO), uint32(REGTMP))
		o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(REGTMP), uint32(REGTMP))
		o3 = OP_RRR(oprrr(ctxt, AADDVU), uint32(r), uint32(REGTMP), uint32(REGTMP))
		o4 = OP_IRR(opirr(ctxt, int(p.As)+ALAST), uint32(0), uint32(REGTMP), uint32(p.To.Reg))

	case 37: /* movw r,mr */
		a := SP(2, 0) | (4 << 21) /* mtc0 */
		if p.As == AMOVV {
			a = SP(2, 0) | (5 << 21) /* dmtc0 */
		}
		o1 = OP_RRR(a, uint32(p.From.Reg), uint32(0), uint32(p.To.Reg))

	case 38: /* movw mr,r */
		a := SP(2, 0) | (0 << 21) /* mfc0 */
		if p.As == AMOVV {
			a = SP(2, 0) | (1 << 21) /* dmfc0 */
		}
		o1 = OP_RRR(a, uint32(p.To.Reg), uint32(0), uint32(p.From.Reg))

	case 40: /* word */
		o1 = uint32(regoff(ctxt, &p.From))

	case 41: /* movw f,fcr */
		o1 = OP_RRR(SP(2, 1)|(2<<21), uint32(REGZERO), uint32(0), uint32(p.To.Reg))    /* mfcc1 */
		o2 = OP_RRR(SP(2, 1)|(6<<21), uint32(p.From.Reg), uint32(0), uint32(p.To.Reg)) /* mtcc1 */

	case 42: /* movw fcr,r */
		o1 = OP_RRR(SP(2, 1)|(2<<21), uint32(p.To.Reg), uint32(0), uint32(p.From.Reg)) /* mfcc1 */

	case 47: /* movv r,fr */
		a := SP(2, 1) | (5 << 21) /* dmtc1 */
		o1 = OP_RRR(a, uint32(p.From.Reg), uint32(0), uint32(p.To.Reg))

	case 48: /* movv fr,r */
		a := SP(2, 1) | (1 << 21) /* dmtc1 */
		o1 = OP_RRR(a, uint32(p.To.Reg), uint32(0), uint32(p.From.Reg))

	case 49: /* undef */
		o1 = 8 /* JMP (R0) */

	/* relocation operations */
	case 50: /* mov r,addr ==> lu + or + sw (REGTMP) */
		o1 = OP_IRR(opirr(ctxt, ALAST), uint32(0), uint32(REGZERO), uint32(REGTMP))
		o2 = OP_IRR(opirr(ctxt, AOR), uint32(0), uint32(REGTMP), uint32(REGTMP))
		rel := obj.Addrel(ctxt.Cursym)
		rel.Off = int32(ctxt.Pc)
		rel.Siz = 8
		rel.Sym = p.To.Sym
		rel.Add = p.To.Offset
		rel.Type = obj.R_ADDRMIPS
		o3 = OP_IRR(opirr(ctxt, int(p.As)), uint32(0), uint32(REGTMP), uint32(p.From.Reg))

	case 51: /* mov addr,r ==> lu + or + lw (REGTMP) */
		o1 = OP_IRR(opirr(ctxt, ALAST), uint32(0), uint32(REGZERO), uint32(REGTMP))
		o2 = OP_IRR(opirr(ctxt, AOR), uint32(0), uint32(REGTMP), uint32(REGTMP))
		rel := obj.Addrel(ctxt.Cursym)
		rel.Off = int32(ctxt.Pc)
		rel.Siz = 8
		rel.Sym = p.From.Sym
		rel.Add = p.From.Offset
		rel.Type = obj.R_ADDRMIPS
		o3 = OP_IRR(opirr(ctxt, int(p.As)+ALAST), uint32(0), uint32(REGTMP), uint32(p.To.Reg))
	}

	out[0] = o1
	out[1] = o2
	out[2] = o3
	out[3] = o4
	return
}
Esempio n. 2
0
File: obj9.go Progetto: ckeyer/gosrc
func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
	// 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
	textstksiz := p.To.Offset
	if textstksiz == -8 {
		// Compatibility hack.
		p.From3.Offset |= obj.NOFRAME
		textstksiz = 0
	}
	if textstksiz%8 != 0 {
		ctxt.Diag("frame size %d not a multiple of 8", textstksiz)
	}
	if p.From3.Offset&obj.NOFRAME != 0 {
		if textstksiz != 0 {
			ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz)
		}
	}

	cursym.Args = p.To.Val.(int32)
	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", obj.Cputime())
	}
	ctxt.Bso.Flush()

	var q *obj.Prog
	var q1 *obj.Prog
	for p := cursym.Text; p != nil; p = p.Link {
		switch p.As {
		/* too hard, just leave alone */
		case obj.ATEXT:
			q = p

			p.Mark |= LABEL | LEAF | SYNC
			if p.Link != nil {
				p.Link.Mark |= LABEL
			}

		case ANOR:
			q = p
			if p.To.Type == obj.TYPE_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
			if p.From.Reg >= REG_SPECIAL || p.To.Reg >= REG_SPECIAL {
				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,
			obj.ADUFFZERO,
			obj.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 == obj.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 obj.ARET:
			q = p
			if p.Link != nil {
				p.Link.Mark |= LABEL
			}
			continue

		case obj.ANOP:
			q1 = p.Link
			q.Link = q1 /* q is non-nop */
			q1.Mark |= p.Mark
			continue

		default:
			q = p
			continue
		}
	}

	autosize := int32(0)
	var aoffset int
	var mov int
	var o int
	var p1 *obj.Prog
	var p2 *obj.Prog
	for p := cursym.Text; p != nil; p = p.Link {
		o = int(p.As)
		switch o {
		case obj.ATEXT:
			mov = AMOVD
			aoffset = 0
			autosize = int32(textstksiz)

			if p.Mark&LEAF != 0 && autosize == 0 && p.From3.Offset&obj.NOFRAME == 0 {
				// A leaf function with no locals has no frame.
				p.From3.Offset |= obj.NOFRAME
			}

			if p.From3.Offset&obj.NOFRAME == 0 {
				// If there is a stack frame at all, it includes
				// space to save the LR.
				autosize += int32(ctxt.FixedFrameSize())
			}

			p.To.Offset = int64(autosize)

			q = p

			if ctxt.Flag_shared != 0 && cursym.Name != "runtime.duffzero" && cursym.Name != "runtime.duffcopy" && cursym.Name != "runtime.stackBarrier" {
				// When compiling Go into PIC, all functions must start
				// with instructions to load the TOC pointer into r2:
				//
				//	addis r2, r12, .TOC.-func@ha
				//	addi r2, r2, .TOC.-func@l+4
				//
				// We could probably skip this prologue in some situations
				// but it's a bit subtle. However, it is both safe and
				// necessary to leave the prologue off duffzero and
				// duffcopy as we rely on being able to jump to a specific
				// instruction offset for them, and stackBarrier is only
				// ever called from an overwritten LR-save slot on the
				// stack (when r12 will not be remotely the right thing)
				// but fortunately does not access global data.
				//
				// These are AWORDS because there is no (afaict) way to
				// generate the addis instruction except as part of the
				// load of a large constant, and in that case there is no
				// way to use r12 as the source.
				q = obj.Appendp(ctxt, q)
				q.As = AWORD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = 0x3c4c0000
				q = obj.Appendp(ctxt, q)
				q.As = AWORD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = 0x38420000
				rel := obj.Addrel(ctxt.Cursym)
				rel.Off = 0
				rel.Siz = 8
				rel.Sym = obj.Linklookup(ctxt, ".TOC.", 0)
				rel.Type = obj.R_ADDRPOWER_PCREL
			}

			if cursym.Text.From3.Offset&obj.NOSPLIT == 0 {
				q = stacksplit(ctxt, q, autosize) // emit split check
			}

			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 = obj.Appendp(ctxt, q)
					q.As = AADD
					q.Lineno = p.Lineno
					q.From.Type = obj.TYPE_CONST
					q.From.Offset = int64(-autosize)
					q.To.Type = obj.TYPE_REG
					q.To.Reg = REGSP
					q.Spadj = +autosize
				}
			} else if cursym.Text.Mark&LEAF == 0 {
				// A very few functions that do not return to their caller
				// (e.g. gogo) are not identified as leaves but still have
				// no frame.
				cursym.Text.Mark |= LEAF
			}

			if cursym.Text.Mark&LEAF != 0 {
				cursym.Leaf = 1
				break
			}

			q = obj.Appendp(ctxt, q)
			q.As = AMOVD
			q.Lineno = p.Lineno
			q.From.Type = obj.TYPE_REG
			q.From.Reg = REG_LR
			q.To.Type = obj.TYPE_REG
			q.To.Reg = REGTMP

			q = obj.Appendp(ctxt, q)
			q.As = int16(mov)
			q.Lineno = p.Lineno
			q.From.Type = obj.TYPE_REG
			q.From.Reg = REGTMP
			q.To.Type = obj.TYPE_MEM
			q.To.Offset = int64(aoffset)
			q.To.Reg = REGSP
			if q.As == AMOVDU {
				q.Spadj = int32(-aoffset)
			}

			if ctxt.Flag_shared != 0 {
				q = obj.Appendp(ctxt, q)
				q.As = AMOVD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R2
				q.To.Type = obj.TYPE_MEM
				q.To.Reg = REGSP
				q.To.Offset = 24
			}

			if cursym.Text.From3.Offset&obj.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 = obj.Appendp(ctxt, q)

				q.As = AMOVD
				q.From.Type = obj.TYPE_MEM
				q.From.Reg = REGG
				q.From.Offset = 4 * int64(ctxt.Arch.Ptrsize) // G.panic
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R3

				q = obj.Appendp(ctxt, q)
				q.As = ACMP
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R0
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R3

				q = obj.Appendp(ctxt, q)
				q.As = ABEQ
				q.To.Type = obj.TYPE_BRANCH
				p1 = q

				q = obj.Appendp(ctxt, q)
				q.As = AMOVD
				q.From.Type = obj.TYPE_MEM
				q.From.Reg = REG_R3
				q.From.Offset = 0 // Panic.argp
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R4

				q = obj.Appendp(ctxt, q)
				q.As = AADD
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = int64(autosize) + ctxt.FixedFrameSize()
				q.Reg = REGSP
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R5

				q = obj.Appendp(ctxt, q)
				q.As = ACMP
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R4
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R5

				q = obj.Appendp(ctxt, q)
				q.As = ABNE
				q.To.Type = obj.TYPE_BRANCH
				p2 = q

				q = obj.Appendp(ctxt, q)
				q.As = AADD
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = ctxt.FixedFrameSize()
				q.Reg = REGSP
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R6

				q = obj.Appendp(ctxt, q)
				q.As = AMOVD
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_R6
				q.To.Type = obj.TYPE_MEM
				q.To.Reg = REG_R3
				q.To.Offset = 0 // Panic.argp

				q = obj.Appendp(ctxt, q)

				q.As = obj.ANOP
				p1.Pcond = q
				p2.Pcond = q
			}

		case obj.ARET:
			if p.From.Type == obj.TYPE_CONST {
				ctxt.Diag("using BECOME (%v) is not supported!", p)
				break
			}

			retTarget := p.To.Sym

			if cursym.Text.Mark&LEAF != 0 {
				if autosize == 0 {
					p.As = ABR
					p.From = obj.Addr{}
					if retTarget == nil {
						p.To.Type = obj.TYPE_REG
						p.To.Reg = REG_LR
					} else {
						p.To.Type = obj.TYPE_BRANCH
						p.To.Sym = retTarget
					}
					p.Mark |= BRANCH
					break
				}

				p.As = AADD
				p.From.Type = obj.TYPE_CONST
				p.From.Offset = int64(autosize)
				p.To.Type = obj.TYPE_REG
				p.To.Reg = REGSP
				p.Spadj = -autosize

				q = ctxt.NewProg()
				q.As = ABR
				q.Lineno = p.Lineno
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_LR
				q.Mark |= BRANCH
				q.Spadj = +autosize

				q.Link = p.Link
				p.Link = q
				break
			}

			p.As = AMOVD
			p.From.Type = obj.TYPE_MEM
			p.From.Offset = 0
			p.From.Reg = REGSP
			p.To.Type = obj.TYPE_REG
			p.To.Reg = REGTMP

			q = ctxt.NewProg()
			q.As = AMOVD
			q.Lineno = p.Lineno
			q.From.Type = obj.TYPE_REG
			q.From.Reg = REGTMP
			q.To.Type = obj.TYPE_REG
			q.To.Reg = REG_LR

			q.Link = p.Link
			p.Link = q
			p = q

			if false {
				// Debug bad returns
				q = ctxt.NewProg()

				q.As = AMOVD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_MEM
				q.From.Offset = 0
				q.From.Reg = REGTMP
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REGTMP

				q.Link = p.Link
				p.Link = q
				p = q
			}

			if autosize != 0 {
				q = ctxt.NewProg()
				q.As = AADD
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = int64(autosize)
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REGSP
				q.Spadj = -autosize

				q.Link = p.Link
				p.Link = q
			}

			q1 = ctxt.NewProg()
			q1.As = ABR
			q1.Lineno = p.Lineno
			if retTarget == nil {
				q1.To.Type = obj.TYPE_REG
				q1.To.Reg = REG_LR
			} else {
				q1.To.Type = obj.TYPE_BRANCH
				q1.To.Sym = retTarget
			}
			q1.Mark |= BRANCH
			q1.Spadj = +autosize

			q1.Link = q.Link
			q.Link = q1
		case AADD:
			if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
				p.Spadj = int32(-p.From.Offset)
			}
		}
	}
}