Golang bootstrap-compile-internal-gc.Fatalf类(方法)实例源码

/*
 * n is a 64-bit value.  fill in lo and hi to refer to its 32-bit halves.
 */
func split64(n *gc.Node, lo *gc.Node, hi *gc.Node) {
	if !gc.Is64(n.Type) {
		gc.Fatalf("split64 %v", n.Type)
	}

	if nsclean >= len(sclean) {
		gc.Fatalf("split64 clean")
	}
	sclean[nsclean].Op = gc.OEMPTY
	nsclean++
	switch n.Op {
	default:
		switch n.Op {
		default:
			var n1 gc.Node
			if !dotaddable(n, &n1) {
				gc.Igen(n, &n1, nil)
				sclean[nsclean-1] = n1
			}

			n = &n1

		case gc.ONAME:
			if n.Class == gc.PPARAMREF {
				var n1 gc.Node
				gc.Cgen(n.Name.Heapaddr, &n1)
				sclean[nsclean-1] = n1
				n = &n1
			}

			// nothing
		case gc.OINDREG:
			break
		}

		*lo = *n
		*hi = *n
		lo.Type = gc.Types[gc.TUINT32]
		if n.Type.Etype == gc.TINT64 {
			hi.Type = gc.Types[gc.TINT32]
		} else {
			hi.Type = gc.Types[gc.TUINT32]
		}
		hi.Xoffset += 4

	case gc.OLITERAL:
		var n1 gc.Node
		n.Convconst(&n1, n.Type)
		i := n1.Int()
		gc.Nodconst(lo, gc.Types[gc.TUINT32], int64(uint32(i)))
		i >>= 32
		if n.Type.Etype == gc.TINT64 {
			gc.Nodconst(hi, gc.Types[gc.TINT32], int64(int32(i)))
		} else {
			gc.Nodconst(hi, gc.Types[gc.TUINT32], int64(uint32(i)))
		}
	}
}

func defframe(ptxt *obj.Prog) {
	var n *gc.Node

	// fill in argument size, stack size
	ptxt.To.Type = obj.TYPE_TEXTSIZE

	ptxt.To.Val = int32(gc.Rnd(gc.Curfn.Type.Argwid, int64(gc.Widthptr)))
	frame := uint32(gc.Rnd(gc.Stksize+gc.Maxarg, int64(gc.Widthreg)))

	// arm64 requires that the frame size (not counting saved LR)
	// be empty or be 8 mod 16. If not, pad it.
	if frame != 0 && frame%16 != 8 {
		frame += 8
	}

	ptxt.To.Offset = int64(frame)

	// insert code to zero ambiguously live variables
	// so that the garbage collector only sees initialized values
	// when it looks for pointers.
	p := ptxt

	hi := int64(0)
	lo := hi

	// iterate through declarations - they are sorted in decreasing xoffset order.
	for l := gc.Curfn.Func.Dcl; l != nil; l = l.Next {
		n = l.N
		if !n.Name.Needzero {
			continue
		}
		if n.Class != gc.PAUTO {
			gc.Fatalf("needzero class %d", n.Class)
		}
		if n.Type.Width%int64(gc.Widthptr) != 0 || n.Xoffset%int64(gc.Widthptr) != 0 || n.Type.Width == 0 {
			gc.Fatalf("var %v has size %d offset %d", gc.Nconv(n, obj.FmtLong), int(n.Type.Width), int(n.Xoffset))
		}

		if lo != hi && n.Xoffset+n.Type.Width >= lo-int64(2*gc.Widthreg) {
			// merge with range we already have
			lo = n.Xoffset

			continue
		}

		// zero old range
		p = zerorange(p, int64(frame), lo, hi)

		// set new range
		hi = n.Xoffset + n.Type.Width

		lo = n.Xoffset
	}

	// zero final range
	zerorange(p, int64(frame), lo, hi)
}

/*
 * insert n into reg slot of p
 */
func raddr(n *gc.Node, p *obj.Prog) {
	var a obj.Addr
	gc.Naddr(&a, n)
	if a.Type != obj.TYPE_REG {
		if n != nil {
			gc.Fatalf("bad in raddr: %v", gc.Oconv(int(n.Op), 0))
		} else {
			gc.Fatalf("bad in raddr: <null>")
		}
		p.Reg = 0
	} else {
		p.Reg = a.Reg
	}
}

/*
 * generate
 *	as n, $c (CMP/CMPU)
 */
func ginscon2(as int, n2 *gc.Node, c int64) {
	var n1 gc.Node

	gc.Nodconst(&n1, gc.Types[gc.TINT64], c)

	switch as {
	default:
		gc.Fatalf("ginscon2")

	case ppc64.ACMP:
		if -ppc64.BIG <= c && c <= ppc64.BIG {
			rawgins(as, n2, &n1)
			return
		}

	case ppc64.ACMPU:
		if 0 <= c && c <= 2*ppc64.BIG {
			rawgins(as, n2, &n1)
			return
		}
	}

	// MOV n1 into register first
	var ntmp gc.Node
	gc.Regalloc(&ntmp, gc.Types[gc.TINT64], nil)

	rawgins(ppc64.AMOVD, &n1, &ntmp)
	rawgins(as, n2, &ntmp)
	gc.Regfree(&ntmp)
}

func proginfo(p *obj.Prog) {
	info := &p.Info
	*info = progtable[p.As]
	if info.Flags == 0 {
		gc.Fatalf("unknown instruction %v", p)
	}

	if p.From.Type == obj.TYPE_ADDR && p.From.Sym != nil && (info.Flags&gc.LeftRead != 0) {
		info.Flags &^= gc.LeftRead
		info.Flags |= gc.LeftAddr
	}

	if (info.Flags&gc.RegRead != 0) && p.Reg == 0 {
		info.Flags &^= gc.RegRead
		info.Flags |= gc.CanRegRead | gc.RightRead
	}

	if (p.Scond&arm.C_SCOND != arm.C_SCOND_NONE) && (info.Flags&gc.RightWrite != 0) {
		info.Flags |= gc.RightRead
	}

	switch p.As {
	case arm.ADIV,
		arm.ADIVU,
		arm.AMOD,
		arm.AMODU:
		info.Regset |= RtoB(arm.REG_R12)
	}
}

func splitclean() {
	if nsclean <= 0 {
		gc.Fatalf("splitclean")
	}
	nsclean--
	if sclean[nsclean].Op != gc.OEMPTY {
		gc.Regfree(&sclean[nsclean])
	}
}

func gcmp(as int, lhs *gc.Node, rhs *gc.Node) *obj.Prog {
	if lhs.Op != gc.OREGISTER {
		gc.Fatalf("bad operands to gcmp: %v %v", gc.Oconv(int(lhs.Op), 0), gc.Oconv(int(rhs.Op), 0))
	}

	p := rawgins(as, rhs, nil)
	raddr(lhs, p)
	return p
}

// as2variant returns the variant (V_*) flags of instruction as.
func as2variant(as int) int {
	initvariants()
	for i := int(0); i < len(varianttable[as]); i++ {
		if varianttable[as][i] == as {
			return i
		}
	}
	gc.Fatalf("as2variant: instruction %v is not a variant of itself", obj.Aconv(as))
	return 0
}

/*
 * generate high multiply:
 *   res = (nl*nr) >> width
 */
func cgen_hmul(nl *gc.Node, nr *gc.Node, res *gc.Node) {
	// largest ullman on left.
	if nl.Ullman < nr.Ullman {
		nl, nr = nr, nl
	}

	t := (*gc.Type)(nl.Type)
	w := int(int(t.Width * 8))
	var n1 gc.Node
	gc.Cgenr(nl, &n1, res)
	var n2 gc.Node
	gc.Cgenr(nr, &n2, nil)
	switch gc.Simtype[t.Etype] {
	case gc.TINT8,
		gc.TINT16,
		gc.TINT32:
		gins3(optoas(gc.OMUL, t), &n2, &n1, nil)
		var lo gc.Node
		gc.Nodreg(&lo, gc.Types[gc.TUINT64], mips.REG_LO)
		gins(mips.AMOVV, &lo, &n1)
		p := (*obj.Prog)(gins(mips.ASRAV, nil, &n1))
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = int64(w)

	case gc.TUINT8,
		gc.TUINT16,
		gc.TUINT32:
		gins3(optoas(gc.OMUL, t), &n2, &n1, nil)
		var lo gc.Node
		gc.Nodreg(&lo, gc.Types[gc.TUINT64], mips.REG_LO)
		gins(mips.AMOVV, &lo, &n1)
		p := (*obj.Prog)(gins(mips.ASRLV, nil, &n1))
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = int64(w)

	case gc.TINT64,
		gc.TUINT64:
		if gc.Issigned[t.Etype] {
			gins3(mips.AMULV, &n2, &n1, nil)
		} else {
			gins3(mips.AMULVU, &n2, &n1, nil)
		}
		var hi gc.Node
		gc.Nodreg(&hi, gc.Types[gc.TUINT64], mips.REG_HI)
		gins(mips.AMOVV, &hi, &n1)

	default:
		gc.Fatalf("cgen_hmul %v", t)
	}

	gc.Cgen(&n1, res)
	gc.Regfree(&n1)
	gc.Regfree(&n2)
}

/*
 * direct reference,
 * could be set/use depending on
 * semantics
 */
func copyas(a *obj.Addr, v *obj.Addr) bool {
	if x86.REG_AL <= a.Reg && a.Reg <= x86.REG_R15B {
		gc.Fatalf("use of byte register")
	}
	if x86.REG_AL <= v.Reg && v.Reg <= x86.REG_R15B {
		gc.Fatalf("use of byte register")
	}

	if a.Type != v.Type || a.Name != v.Name || a.Reg != v.Reg {
		return false
	}
	if regtyp(v) {
		return true
	}
	if v.Type == obj.TYPE_MEM && (v.Name == obj.NAME_AUTO || v.Name == obj.NAME_PARAM) {
		if v.Offset == a.Offset {
			return true
		}
	}
	return false
}

/* generate a constant shift
 * arm encodes a shift by 32 as 0, thus asking for 0 shift is illegal.
 */
func gshift(as int, lhs *gc.Node, stype int32, sval int32, rhs *gc.Node) *obj.Prog {
	if sval <= 0 || sval > 32 {
		gc.Fatalf("bad shift value: %d", sval)
	}

	sval = sval & 0x1f

	p := gins(as, nil, rhs)
	p.From.Type = obj.TYPE_SHIFT
	p.From.Offset = int64(stype) | int64(sval)<<7 | int64(lhs.Reg)&15
	return p
}

/*
 * generate division according to op, one of:
 *	res = nl / nr
 *	res = nl % nr
 */
func cgen_div(op gc.Op, nl *gc.Node, nr *gc.Node, res *gc.Node) {
	if gc.Is64(nl.Type) {
		gc.Fatalf("cgen_div %v", nl.Type)
	}

	var t *gc.Type
	if gc.Issigned[nl.Type.Etype] {
		t = gc.Types[gc.TINT32]
	} else {
		t = gc.Types[gc.TUINT32]
	}
	var ax gc.Node
	var oldax gc.Node
	savex(x86.REG_AX, &ax, &oldax, res, t)
	var olddx gc.Node
	var dx gc.Node
	savex(x86.REG_DX, &dx, &olddx, res, t)
	dodiv(op, nl, nr, res, &ax, &dx)
	restx(&dx, &olddx)
	restx(&ax, &oldax)
}

// Called after regopt and peep have run.
// Expand CHECKNIL pseudo-op into actual nil pointer check.
func expandchecks(firstp *obj.Prog) {
	var p1 *obj.Prog

	for p := (*obj.Prog)(firstp); p != nil; p = p.Link {
		if gc.Debug_checknil != 0 && gc.Ctxt.Debugvlog != 0 {
			fmt.Printf("expandchecks: %v\n", p)
		}
		if p.As != obj.ACHECKNIL {
			continue
		}
		if gc.Debug_checknil != 0 && p.Lineno > 1 { // p->lineno==1 in generated wrappers
			gc.Warnl(int(p.Lineno), "generated nil check")
		}
		if p.From.Type != obj.TYPE_REG {
			gc.Fatalf("invalid nil check %v\n", p)
		}

		// check is
		//	CBNZ arg, 2(PC)
		//	MOVD ZR, 0(arg)
		p1 = gc.Ctxt.NewProg()
		gc.Clearp(p1)
		p1.Link = p.Link
		p.Link = p1
		p1.Lineno = p.Lineno
		p1.Pc = 9999

		p.As = arm64.ACBNZ
		p.To.Type = obj.TYPE_BRANCH
		p.To.Val = p1.Link

		// crash by write to memory address 0.
		p1.As = arm64.AMOVD
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = arm64.REGZERO
		p1.To.Type = obj.TYPE_MEM
		p1.To.Reg = p.From.Reg
		p1.To.Offset = 0
	}
}

// jmptoset returns ASETxx for AJxx.
func jmptoset(jmp int) int {
	switch jmp {
	case x86.AJEQ:
		return x86.ASETEQ
	case x86.AJNE:
		return x86.ASETNE
	case x86.AJLT:
		return x86.ASETLT
	case x86.AJCS:
		return x86.ASETCS
	case x86.AJLE:
		return x86.ASETLE
	case x86.AJLS:
		return x86.ASETLS
	case x86.AJGT:
		return x86.ASETGT
	case x86.AJHI:
		return x86.ASETHI
	case x86.AJGE:
		return x86.ASETGE
	case x86.AJCC:
		return x86.ASETCC
	case x86.AJMI:
		return x86.ASETMI
	case x86.AJOC:
		return x86.ASETOC
	case x86.AJOS:
		return x86.ASETOS
	case x86.AJPC:
		return x86.ASETPC
	case x86.AJPL:
		return x86.ASETPL
	case x86.AJPS:
		return x86.ASETPS
	}
	gc.Fatalf("jmptoset: no entry for %v", gc.Oconv(jmp, 0))
	panic("unreachable")
}

func zerorange(p *obj.Prog, frame int64, lo int64, hi int64, ax *uint32, x0 *uint32) *obj.Prog {
	cnt := hi - lo
	if cnt == 0 {
		return p
	}

	if cnt%int64(gc.Widthreg) != 0 {
		// should only happen with nacl
		if cnt%int64(gc.Widthptr) != 0 {
			gc.Fatalf("zerorange count not a multiple of widthptr %d", cnt)
		}
		if *ax == 0 {
			p = appendpp(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_AX, 0)
			*ax = 1
		}
		p = appendpp(p, x86.AMOVL, obj.TYPE_REG, x86.REG_AX, 0, obj.TYPE_MEM, x86.REG_SP, frame+lo)
		lo += int64(gc.Widthptr)
		cnt -= int64(gc.Widthptr)
	}

	if cnt == 8 {
		if *ax == 0 {
			p = appendpp(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_AX, 0)
			*ax = 1
		}
		p = appendpp(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_AX, 0, obj.TYPE_MEM, x86.REG_SP, frame+lo)
	} else if cnt <= int64(8*gc.Widthreg) {
		if *x0 == 0 {
			p = appendpp(p, x86.AXORPS, obj.TYPE_REG, x86.REG_X0, 0, obj.TYPE_REG, x86.REG_X0, 0)
			*x0 = 1
		}

		for i := int64(0); i < cnt/16; i++ {
			p = appendpp(p, x86.AMOVUPS, obj.TYPE_REG, x86.REG_X0, 0, obj.TYPE_MEM, x86.REG_SP, frame+lo+i*16)
		}

		if cnt%16 != 0 {
			p = appendpp(p, x86.AMOVUPS, obj.TYPE_REG, x86.REG_X0, 0, obj.TYPE_MEM, x86.REG_SP, frame+lo+cnt-int64(16))
		}
	} else if !gc.Nacl && (cnt <= int64(128*gc.Widthreg)) {
		if *x0 == 0 {
			p = appendpp(p, x86.AXORPS, obj.TYPE_REG, x86.REG_X0, 0, obj.TYPE_REG, x86.REG_X0, 0)
			*x0 = 1
		}

		p = appendpp(p, leaptr, obj.TYPE_MEM, x86.REG_SP, frame+lo+dzDI(cnt), obj.TYPE_REG, x86.REG_DI, 0)
		p = appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_ADDR, 0, dzOff(cnt))
		p.To.Sym = gc.Linksym(gc.Pkglookup("duffzero", gc.Runtimepkg))

		if cnt%16 != 0 {
			p = appendpp(p, x86.AMOVUPS, obj.TYPE_REG, x86.REG_X0, 0, obj.TYPE_MEM, x86.REG_DI, -int64(8))
		}
	} else {
		if *ax == 0 {
			p = appendpp(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_AX, 0)
			*ax = 1
		}

		p = appendpp(p, x86.AMOVQ, obj.TYPE_CONST, 0, cnt/int64(gc.Widthreg), obj.TYPE_REG, x86.REG_CX, 0)
		p = appendpp(p, leaptr, obj.TYPE_MEM, x86.REG_SP, frame+lo, obj.TYPE_REG, x86.REG_DI, 0)
		p = appendpp(p, x86.AREP, obj.TYPE_NONE, 0, 0, obj.TYPE_NONE, 0, 0)
		p = appendpp(p, x86.ASTOSQ, obj.TYPE_NONE, 0, 0, obj.TYPE_NONE, 0, 0)
	}

	return p
}

/*
 * return Axxx for Oxxx on type t.
 */
func optoas(op gc.Op, t *gc.Type) int {
	if t == nil {
		gc.Fatalf("optoas: t is nil")
	}

	// avoid constant conversions in switches below
	const (
		OMINUS_ = uint32(gc.OMINUS) << 16
		OLSH_   = uint32(gc.OLSH) << 16
		ORSH_   = uint32(gc.ORSH) << 16
		OADD_   = uint32(gc.OADD) << 16
		OSUB_   = uint32(gc.OSUB) << 16
		OMUL_   = uint32(gc.OMUL) << 16
		ODIV_   = uint32(gc.ODIV) << 16
		OOR_    = uint32(gc.OOR) << 16
		OAND_   = uint32(gc.OAND) << 16
		OXOR_   = uint32(gc.OXOR) << 16
		OEQ_    = uint32(gc.OEQ) << 16
		ONE_    = uint32(gc.ONE) << 16
		OLT_    = uint32(gc.OLT) << 16
		OLE_    = uint32(gc.OLE) << 16
		OGE_    = uint32(gc.OGE) << 16
		OGT_    = uint32(gc.OGT) << 16
		OCMP_   = uint32(gc.OCMP) << 16
		OAS_    = uint32(gc.OAS) << 16
		OHMUL_  = uint32(gc.OHMUL) << 16
	)

	a := int(obj.AXXX)
	switch uint32(op)<<16 | uint32(gc.Simtype[t.Etype]) {
	default:
		gc.Fatalf("optoas: no entry for op=%v type=%v", gc.Oconv(int(op), 0), t)

	case OEQ_ | gc.TBOOL,
		OEQ_ | gc.TINT8,
		OEQ_ | gc.TUINT8,
		OEQ_ | gc.TINT16,
		OEQ_ | gc.TUINT16,
		OEQ_ | gc.TINT32,
		OEQ_ | gc.TUINT32,
		OEQ_ | gc.TINT64,
		OEQ_ | gc.TUINT64,
		OEQ_ | gc.TPTR32,
		OEQ_ | gc.TPTR64,
		OEQ_ | gc.TFLOAT32,
		OEQ_ | gc.TFLOAT64:
		a = ppc64.ABEQ

	case ONE_ | gc.TBOOL,
		ONE_ | gc.TINT8,
		ONE_ | gc.TUINT8,
		ONE_ | gc.TINT16,
		ONE_ | gc.TUINT16,
		ONE_ | gc.TINT32,
		ONE_ | gc.TUINT32,
		ONE_ | gc.TINT64,
		ONE_ | gc.TUINT64,
		ONE_ | gc.TPTR32,
		ONE_ | gc.TPTR64,
		ONE_ | gc.TFLOAT32,
		ONE_ | gc.TFLOAT64:
		a = ppc64.ABNE

	case OLT_ | gc.TINT8, // ACMP
		OLT_ | gc.TINT16,
		OLT_ | gc.TINT32,
		OLT_ | gc.TINT64,
		OLT_ | gc.TUINT8,
		// ACMPU
		OLT_ | gc.TUINT16,
		OLT_ | gc.TUINT32,
		OLT_ | gc.TUINT64,
		OLT_ | gc.TFLOAT32,
		// AFCMPU
		OLT_ | gc.TFLOAT64:
		a = ppc64.ABLT

	case OLE_ | gc.TINT8, // ACMP
		OLE_ | gc.TINT16,
		OLE_ | gc.TINT32,
		OLE_ | gc.TINT64,
		OLE_ | gc.TUINT8,
		// ACMPU
		OLE_ | gc.TUINT16,
		OLE_ | gc.TUINT32,
		OLE_ | gc.TUINT64:
		// No OLE for floats, because it mishandles NaN.
		// Front end must reverse comparison or use OLT and OEQ together.
		a = ppc64.ABLE

	case OGT_ | gc.TINT8,
		OGT_ | gc.TINT16,
		OGT_ | gc.TINT32,
		OGT_ | gc.TINT64,
		OGT_ | gc.TUINT8,
		OGT_ | gc.TUINT16,
		OGT_ | gc.TUINT32,
//.........这里部分代码省略.........

/*
 * generate one instruction:
 *	as f, t
 */
func rawgins(as int, f *gc.Node, t *gc.Node) *obj.Prog {
	// TODO(austin): Add self-move test like in 6g (but be careful
	// of truncation moves)

	p := gc.Prog(as)
	gc.Naddr(&p.From, f)
	gc.Naddr(&p.To, t)

	switch as {
	case obj.ACALL:
		if p.To.Type == obj.TYPE_REG && p.To.Reg != ppc64.REG_CTR {
			// Allow front end to emit CALL REG, and rewrite into MOV REG, CTR; CALL CTR.
			if gc.Ctxt.Flag_shared != 0 {
				// Make sure function pointer is in R12 as well when
				// compiling Go into PIC.
				// TODO(mwhudson): it would obviously be better to
				// change the register allocation to put the value in
				// R12 already, but I don't know how to do that.
				q := gc.Prog(as)
				q.As = ppc64.AMOVD
				q.From = p.To
				q.To.Type = obj.TYPE_REG
				q.To.Reg = ppc64.REG_R12
			}
			pp := gc.Prog(as)
			pp.From = p.From
			pp.To.Type = obj.TYPE_REG
			pp.To.Reg = ppc64.REG_CTR

			p.As = ppc64.AMOVD
			p.From = p.To
			p.To.Type = obj.TYPE_REG
			p.To.Reg = ppc64.REG_CTR

			if gc.Ctxt.Flag_shared != 0 {
				// When compiling Go into PIC, the function we just
				// called via pointer might have been implemented in
				// a separate module and so overwritten the TOC
				// pointer in R2; reload it.
				q := gc.Prog(ppc64.AMOVD)
				q.From.Type = obj.TYPE_MEM
				q.From.Offset = 24
				q.From.Reg = ppc64.REGSP
				q.To.Type = obj.TYPE_REG
				q.To.Reg = ppc64.REG_R2
			}

			if gc.Debug['g'] != 0 {
				fmt.Printf("%v\n", p)
				fmt.Printf("%v\n", pp)
			}

			return pp
		}

	// Bad things the front end has done to us. Crash to find call stack.
	case ppc64.AAND, ppc64.AMULLD:
		if p.From.Type == obj.TYPE_CONST {
			gc.Debug['h'] = 1
			gc.Fatalf("bad inst: %v", p)
		}
	case ppc64.ACMP, ppc64.ACMPU:
		if p.From.Type == obj.TYPE_MEM || p.To.Type == obj.TYPE_MEM {
			gc.Debug['h'] = 1
			gc.Fatalf("bad inst: %v", p)
		}
	}

	if gc.Debug['g'] != 0 {
		fmt.Printf("%v\n", p)
	}

	w := int32(0)
	switch as {
	case ppc64.AMOVB,
		ppc64.AMOVBU,
		ppc64.AMOVBZ,
		ppc64.AMOVBZU:
		w = 1

	case ppc64.AMOVH,
		ppc64.AMOVHU,
		ppc64.AMOVHZ,
		ppc64.AMOVHZU:
		w = 2

	case ppc64.AMOVW,
		ppc64.AMOVWU,
		ppc64.AMOVWZ,
		ppc64.AMOVWZU:
		w = 4

	case ppc64.AMOVD,
		ppc64.AMOVDU:
		if p.From.Type == obj.TYPE_CONST || p.From.Type == obj.TYPE_ADDR {
			break
//.........这里部分代码省略.........

/*
 * generate move:
 *	t = f
 * hard part is conversions.
 */
func gmove(f *gc.Node, t *gc.Node) {
	if gc.Debug['M'] != 0 {
		fmt.Printf("gmove %v -> %v\n", gc.Nconv(f, obj.FmtLong), gc.Nconv(t, obj.FmtLong))
	}

	ft := int(gc.Simsimtype(f.Type))
	tt := int(gc.Simsimtype(t.Type))
	cvt := (*gc.Type)(t.Type)

	if gc.Iscomplex[ft] || gc.Iscomplex[tt] {
		gc.Complexmove(f, t)
		return
	}

	// cannot have two memory operands
	var r2 gc.Node
	var r1 gc.Node
	var a int
	if gc.Ismem(f) && gc.Ismem(t) {
		goto hard
	}

	// convert constant to desired type
	if f.Op == gc.OLITERAL {
		var con gc.Node
		switch tt {
		default:
			f.Convconst(&con, t.Type)

		case gc.TINT32,
			gc.TINT16,
			gc.TINT8:
			var con gc.Node
			f.Convconst(&con, gc.Types[gc.TINT64])
			var r1 gc.Node
			gc.Regalloc(&r1, con.Type, t)
			gins(ppc64.AMOVD, &con, &r1)
			gmove(&r1, t)
			gc.Regfree(&r1)
			return

		case gc.TUINT32,
			gc.TUINT16,
			gc.TUINT8:
			var con gc.Node
			f.Convconst(&con, gc.Types[gc.TUINT64])
			var r1 gc.Node
			gc.Regalloc(&r1, con.Type, t)
			gins(ppc64.AMOVD, &con, &r1)
			gmove(&r1, t)
			gc.Regfree(&r1)
			return
		}

		f = &con
		ft = tt // so big switch will choose a simple mov

		// constants can't move directly to memory.
		if gc.Ismem(t) {
			goto hard
		}
	}

	// float constants come from memory.
	//if(isfloat[tt])
	//	goto hard;

	// 64-bit immediates are also from memory.
	//if(isint[tt])
	//	goto hard;
	//// 64-bit immediates are really 32-bit sign-extended
	//// unless moving into a register.
	//if(isint[tt]) {
	//	if(mpcmpfixfix(con.val.u.xval, minintval[TINT32]) < 0)
	//		goto hard;
	//	if(mpcmpfixfix(con.val.u.xval, maxintval[TINT32]) > 0)
	//		goto hard;
	//}

	// value -> value copy, only one memory operand.
	// figure out the instruction to use.
	// break out of switch for one-instruction gins.
	// goto rdst for "destination must be register".
	// goto hard for "convert to cvt type first".
	// otherwise handle and return.

	switch uint32(ft)<<16 | uint32(tt) {
	default:
		gc.Fatalf("gmove %v -> %v", gc.Tconv(f.Type, obj.FmtLong), gc.Tconv(t.Type, obj.FmtLong))

		/*
		 * integer copy and truncate
		 */
	case gc.TINT8<<16 | gc.TINT8, // same size
		gc.TUINT8<<16 | gc.TINT8,
//.........这里部分代码省略.........

func clearfat(nl *gc.Node) {
	/* clear a fat object */
	if gc.Debug['g'] != 0 {
		fmt.Printf("clearfat %v (%v, size: %d)\n", nl, nl.Type, nl.Type.Width)
	}

	w := uint64(uint64(nl.Type.Width))

	// Avoid taking the address for simple enough types.
	if gc.Componentgen(nil, nl) {
		return
	}

	c := uint64(w % 8) // bytes
	q := uint64(w / 8) // dwords

	if gc.Reginuse(ppc64.REGRT1) {
		gc.Fatalf("%v in use during clearfat", obj.Rconv(ppc64.REGRT1))
	}

	var r0 gc.Node
	gc.Nodreg(&r0, gc.Types[gc.TUINT64], ppc64.REGZERO)
	var dst gc.Node
	gc.Nodreg(&dst, gc.Types[gc.Tptr], ppc64.REGRT1)
	gc.Regrealloc(&dst)
	gc.Agen(nl, &dst)

	var boff uint64
	if q > 128 {
		p := gins(ppc64.ASUB, nil, &dst)
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = 8

		var end gc.Node
		gc.Regalloc(&end, gc.Types[gc.Tptr], nil)
		p = gins(ppc64.AMOVD, &dst, &end)
		p.From.Type = obj.TYPE_ADDR
		p.From.Offset = int64(q * 8)

		p = gins(ppc64.AMOVDU, &r0, &dst)
		p.To.Type = obj.TYPE_MEM
		p.To.Offset = 8
		pl := (*obj.Prog)(p)

		p = gins(ppc64.ACMP, &dst, &end)
		gc.Patch(gc.Gbranch(ppc64.ABNE, nil, 0), pl)

		gc.Regfree(&end)

		// The loop leaves R3 on the last zeroed dword
		boff = 8
	} else if q >= 4 {
		p := gins(ppc64.ASUB, nil, &dst)
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = 8
		f := (*gc.Node)(gc.Sysfunc("duffzero"))
		p = gins(obj.ADUFFZERO, nil, f)
		gc.Afunclit(&p.To, f)

		// 4 and 128 = magic constants: see ../../runtime/asm_ppc64x.s
		p.To.Offset = int64(4 * (128 - q))

		// duffzero leaves R3 on the last zeroed dword
		boff = 8
	} else {
		var p *obj.Prog
		for t := uint64(0); t < q; t++ {
			p = gins(ppc64.AMOVD, &r0, &dst)
			p.To.Type = obj.TYPE_MEM
			p.To.Offset = int64(8 * t)
		}

		boff = 8 * q
	}

	var p *obj.Prog
	for t := uint64(0); t < c; t++ {
		p = gins(ppc64.AMOVB, &r0, &dst)
		p.To.Type = obj.TYPE_MEM
		p.To.Offset = int64(t + boff)
	}

	gc.Regfree(&dst)
}

/*
 * attempt to generate 64-bit
 *	res = n
 * return 1 on success, 0 if op not handled.
 */
func cgen64(n *gc.Node, res *gc.Node) {
	if res.Op != gc.OINDREG && res.Op != gc.ONAME {
		gc.Dump("n", n)
		gc.Dump("res", res)
		gc.Fatalf("cgen64 %v of %v", gc.Oconv(int(n.Op), 0), gc.Oconv(int(res.Op), 0))
	}

	l := n.Left
	var t1 gc.Node
	if !l.Addable {
		gc.Tempname(&t1, l.Type)
		gc.Cgen(l, &t1)
		l = &t1
	}

	var hi1 gc.Node
	var lo1 gc.Node
	split64(l, &lo1, &hi1)
	switch n.Op {
	default:
		gc.Fatalf("cgen64 %v", gc.Oconv(int(n.Op), 0))

	case gc.OMINUS:
		var lo2 gc.Node
		var hi2 gc.Node
		split64(res, &lo2, &hi2)

		gc.Regalloc(&t1, lo1.Type, nil)
		var al gc.Node
		gc.Regalloc(&al, lo1.Type, nil)
		var ah gc.Node
		gc.Regalloc(&ah, hi1.Type, nil)

		gins(arm.AMOVW, &lo1, &al)
		gins(arm.AMOVW, &hi1, &ah)

		gmove(ncon(0), &t1)
		p1 := gins(arm.ASUB, &al, &t1)
		p1.Scond |= arm.C_SBIT
		gins(arm.AMOVW, &t1, &lo2)

		gmove(ncon(0), &t1)
		gins(arm.ASBC, &ah, &t1)
		gins(arm.AMOVW, &t1, &hi2)

		gc.Regfree(&t1)
		gc.Regfree(&al)
		gc.Regfree(&ah)
		splitclean()
		splitclean()
		return

	case gc.OCOM:
		gc.Regalloc(&t1, lo1.Type, nil)
		gmove(ncon(^uint32(0)), &t1)

		var lo2 gc.Node
		var hi2 gc.Node
		split64(res, &lo2, &hi2)
		var n1 gc.Node
		gc.Regalloc(&n1, lo1.Type, nil)

		gins(arm.AMOVW, &lo1, &n1)
		gins(arm.AEOR, &t1, &n1)
		gins(arm.AMOVW, &n1, &lo2)

		gins(arm.AMOVW, &hi1, &n1)
		gins(arm.AEOR, &t1, &n1)
		gins(arm.AMOVW, &n1, &hi2)

		gc.Regfree(&t1)
		gc.Regfree(&n1)
		splitclean()
		splitclean()
		return

		// binary operators.
	// common setup below.
	case gc.OADD,
		gc.OSUB,
		gc.OMUL,
		gc.OLSH,
		gc.ORSH,
		gc.OAND,
		gc.OOR,
		gc.OXOR,
		gc.OLROT:
		break
	}

	// setup for binary operators
	r := n.Right

	if r != nil && !r.Addable {
		var t2 gc.Node
//.........这里部分代码省略.........