Golang gc.Tempname函數代碼示例

/*
 * generate an addressable node in res, containing the value of n.
 * n is an array index, and might be any size; res width is <= 32-bit.
 * returns Prog* to patch to panic call.
 */
func igenindex(n *gc.Node, res *gc.Node, bounded bool) *obj.Prog {
	if !gc.Is64(n.Type) {
		if n.Addable != 0 {
			// nothing to do.
			*res = *n
		} else {
			gc.Tempname(res, gc.Types[gc.TUINT32])
			gc.Cgen(n, res)
		}

		return nil
	}

	var tmp gc.Node
	gc.Tempname(&tmp, gc.Types[gc.TINT64])
	gc.Cgen(n, &tmp)
	var lo gc.Node
	var hi gc.Node
	split64(&tmp, &lo, &hi)
	gc.Tempname(res, gc.Types[gc.TUINT32])
	gmove(&lo, res)
	if bounded {
		splitclean()
		return nil
	}

	var zero gc.Node
	gc.Nodconst(&zero, gc.Types[gc.TINT32], 0)
	gins(x86.ACMPL, &hi, &zero)
	splitclean()
	return gc.Gbranch(x86.AJNE, nil, +1)
}

/*
 * generate array index into res.
 * n might be any size; res is 32-bit.
 * returns Prog* to patch to panic call.
 */
func cgenindex(n *gc.Node, res *gc.Node, bounded bool) *obj.Prog {
	if !gc.Is64(n.Type) {
		gc.Cgen(n, res)
		return nil
	}

	var tmp gc.Node
	gc.Tempname(&tmp, gc.Types[gc.TINT64])
	gc.Cgen(n, &tmp)
	var lo gc.Node
	var hi gc.Node
	split64(&tmp, &lo, &hi)
	gmove(&lo, res)
	if bounded {
		splitclean()
		return nil
	}

	var n1 gc.Node
	gc.Regalloc(&n1, gc.Types[gc.TINT32], nil)
	var n2 gc.Node
	gc.Regalloc(&n2, gc.Types[gc.TINT32], nil)
	var zero gc.Node
	gc.Nodconst(&zero, gc.Types[gc.TINT32], 0)
	gmove(&hi, &n1)
	gmove(&zero, &n2)
	gins(arm.ACMP, &n1, &n2)
	gc.Regfree(&n2)
	gc.Regfree(&n1)
	splitclean()
	return gc.Gbranch(arm.ABNE, nil, -1)
}

/*
 * generate byte multiply:
 *	res = nl * nr
 * there is no 2-operand byte multiply instruction so
 * we do a full-width multiplication and truncate afterwards.
 */
func cgen_bmul(op int, nl *gc.Node, nr *gc.Node, res *gc.Node) {
	// copy from byte to full registers
	t := gc.Types[gc.TUINT32]

	if gc.Issigned[nl.Type.Etype] {
		t = gc.Types[gc.TINT32]
	}

	// largest ullman on left.
	if nl.Ullman < nr.Ullman {
		tmp := nl
		nl = nr
		nr = tmp
	}

	var nt gc.Node
	gc.Tempname(&nt, nl.Type)
	cgen(nl, &nt)
	var n1 gc.Node
	regalloc(&n1, t, res)
	cgen(nr, &n1)
	var n2 gc.Node
	regalloc(&n2, t, nil)
	gmove(&nt, &n2)
	a := optoas(op, t)
	gins(a, &n2, &n1)
	regfree(&n2)
	gmove(&n1, res)
	regfree(&n1)
}

func savex(dr int, x *gc.Node, oldx *gc.Node, res *gc.Node, t *gc.Type) {
	r := int(reg[dr])
	gc.Nodreg(x, gc.Types[gc.TINT32], dr)

	// save current ax and dx if they are live
	// and not the destination
	*oldx = gc.Node{}

	if r > 0 && !gc.Samereg(x, res) {
		gc.Tempname(oldx, gc.Types[gc.TINT32])
		gmove(x, oldx)
	}

	gc.Regalloc(x, t, x)
}

/*
 * generate function call;
 *	proc=0	normal call
 *	proc=1	goroutine run in new proc
 *	proc=2	defer call save away stack
 */
func cgen_call(n *gc.Node, proc int) {
	if n == nil {
		return
	}

	var afun gc.Node
	if n.Left.Ullman >= gc.UINF {
		// if name involves a fn call
		// precompute the address of the fn
		gc.Tempname(&afun, gc.Types[gc.Tptr])

		cgen(n.Left, &afun)
	}

	gc.Genlist(n.List) // assign the args
	t := n.Left.Type

	// call tempname pointer
	if n.Left.Ullman >= gc.UINF {
		var nod gc.Node
		regalloc(&nod, gc.Types[gc.Tptr], nil)
		gc.Cgen_as(&nod, &afun)
		nod.Type = t
		ginscall(&nod, proc)
		regfree(&nod)
		return
	}

	// call pointer
	if n.Left.Op != gc.ONAME || n.Left.Class != gc.PFUNC {
		var nod gc.Node
		regalloc(&nod, gc.Types[gc.Tptr], nil)
		gc.Cgen_as(&nod, n.Left)
		nod.Type = t
		ginscall(&nod, proc)
		regfree(&nod)
		return
	}

	// call direct
	n.Left.Method = 1

	ginscall(n.Left, proc)
}

/*
 * generate floating-point operation.
 */
func cgen_float(n *gc.Node, res *gc.Node) {
	nl := n.Left
	switch n.Op {
	case gc.OEQ,
		gc.ONE,
		gc.OLT,
		gc.OLE,
		gc.OGE:
		p1 := gc.Gbranch(obj.AJMP, nil, 0)
		p2 := gc.Pc
		gmove(gc.Nodbool(true), res)
		p3 := gc.Gbranch(obj.AJMP, nil, 0)
		gc.Patch(p1, gc.Pc)
		gc.Bgen(n, true, 0, p2)
		gmove(gc.Nodbool(false), res)
		gc.Patch(p3, gc.Pc)
		return

	case gc.OPLUS:
		gc.Cgen(nl, res)
		return

	case gc.OCONV:
		if gc.Eqtype(n.Type, nl.Type) || gc.Noconv(n.Type, nl.Type) {
			gc.Cgen(nl, res)
			return
		}

		var n2 gc.Node
		gc.Tempname(&n2, n.Type)
		var n1 gc.Node
		gc.Mgen(nl, &n1, res)
		gmove(&n1, &n2)
		gmove(&n2, res)
		gc.Mfree(&n1)
		return
	}

	if gc.Thearch.Use387 {
		cgen_float387(n, res)
	} else {
		cgen_floatsse(n, res)
	}
}

/*
 * peep.c
 */
func mgen(n *gc.Node, n1 *gc.Node, rg *gc.Node) {
	n1.Op = gc.OEMPTY

	if n.Addable != 0 {
		*n1 = *n
		if n1.Op == gc.OREGISTER || n1.Op == gc.OINDREG {
			reg[n.Val.U.Reg]++
		}
		return
	}

	gc.Tempname(n1, n.Type)
	cgen(n, n1)
	if n.Type.Width <= int64(gc.Widthptr) || gc.Isfloat[n.Type.Etype] {
		n2 := *n1
		regalloc(n1, n.Type, rg)
		gmove(&n2, n1)
	}
}

/*
 * generate high multiply:
 *   res = (nl*nr) >> width
 */
func cgen_hmul(nl *gc.Node, nr *gc.Node, res *gc.Node) {
	var n1 gc.Node
	var n2 gc.Node
	var ax gc.Node
	var dx gc.Node

	t := nl.Type
	a := optoas(gc.OHMUL, t)

	// gen nl in n1.
	gc.Tempname(&n1, t)

	gc.Cgen(nl, &n1)

	// gen nr in n2.
	gc.Regalloc(&n2, t, res)

	gc.Cgen(nr, &n2)

	// multiply.
	gc.Nodreg(&ax, t, x86.REG_AX)

	gmove(&n2, &ax)
	gins(a, &n1, nil)
	gc.Regfree(&n2)

	if t.Width == 1 {
		// byte multiply behaves differently.
		gc.Nodreg(&ax, t, x86.REG_AH)

		gc.Nodreg(&dx, t, x86.REG_DX)
		gmove(&ax, &dx)
	}

	gc.Nodreg(&dx, t, x86.REG_DX)
	gmove(&dx, res)
}

func memname(n *gc.Node, t *gc.Type) {
	gc.Tempname(n, t)
	n.Sym = gc.Lookup("." + n.Sym.Name[1:]) // keep optimizer from registerizing
	n.Orig.Sym = n.Sym
}

//.........這裏部分代碼省略.........
		gc.TFLOAT64<<16 | gc.TINT8,
		gc.TFLOAT64<<16 | gc.TUINT16,
		gc.TFLOAT64<<16 | gc.TUINT8:
		cvt = gc.Types[gc.TINT32]

		goto hard

		// convert via int64.
	case gc.TFLOAT32<<16 | gc.TUINT32,
		gc.TFLOAT64<<16 | gc.TUINT32:
		cvt = gc.Types[gc.TINT64]

		goto hardmem

	case gc.TFLOAT32<<16 | gc.TINT32:
		a = x86.ACVTTSS2SL
		goto rdst

	case gc.TFLOAT64<<16 | gc.TINT32:
		a = x86.ACVTTSD2SL
		goto rdst

		// convert via int32 memory
	/*
	 * integer to float
	 */
	case gc.TINT8<<16 | gc.TFLOAT32,
		gc.TINT8<<16 | gc.TFLOAT64,
		gc.TINT16<<16 | gc.TFLOAT32,
		gc.TINT16<<16 | gc.TFLOAT64,
		gc.TUINT16<<16 | gc.TFLOAT32,
		gc.TUINT16<<16 | gc.TFLOAT64,
		gc.TUINT8<<16 | gc.TFLOAT32,
		gc.TUINT8<<16 | gc.TFLOAT64:
		cvt = gc.Types[gc.TINT32]

		goto hard

		// convert via int64 memory
	case gc.TUINT32<<16 | gc.TFLOAT32,
		gc.TUINT32<<16 | gc.TFLOAT64:
		cvt = gc.Types[gc.TINT64]

		goto hardmem

	case gc.TINT32<<16 | gc.TFLOAT32:
		a = x86.ACVTSL2SS
		goto rdst

	case gc.TINT32<<16 | gc.TFLOAT64:
		a = x86.ACVTSL2SD
		goto rdst

		/*
		 * float to float
		 */
	case gc.TFLOAT32<<16 | gc.TFLOAT32:
		a = x86.AMOVSS

	case gc.TFLOAT64<<16 | gc.TFLOAT64:
		a = x86.AMOVSD

	case gc.TFLOAT32<<16 | gc.TFLOAT64:
		a = x86.ACVTSS2SD
		goto rdst

	case gc.TFLOAT64<<16 | gc.TFLOAT32:
		a = x86.ACVTSD2SS
		goto rdst
	}

	gins(a, f, t)
	return

	// requires register intermediate
hard:
	gc.Regalloc(&r1, cvt, t)

	gmove(f, &r1)
	gmove(&r1, t)
	gc.Regfree(&r1)
	return

	// requires memory intermediate
hardmem:
	gc.Tempname(&r1, cvt)

	gmove(f, &r1)
	gmove(&r1, t)
	return

	// requires register destination
rdst:
	gc.Regalloc(&r1, t.Type, t)

	gins(a, f, &r1)
	gmove(&r1, t)
	gc.Regfree(&r1)
	return
}

func floatmove_387(f *gc.Node, t *gc.Node) {
	var r1 gc.Node
	var a int

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

	switch uint32(ft)<<16 | uint32(tt) {
	default:
		goto fatal

		/*
		* float to integer
		 */
	case gc.TFLOAT32<<16 | gc.TINT16,
		gc.TFLOAT32<<16 | gc.TINT32,
		gc.TFLOAT32<<16 | gc.TINT64,
		gc.TFLOAT64<<16 | gc.TINT16,
		gc.TFLOAT64<<16 | gc.TINT32,
		gc.TFLOAT64<<16 | gc.TINT64:
		if t.Op == gc.OREGISTER {
			goto hardmem
		}
		var r1 gc.Node
		gc.Nodreg(&r1, gc.Types[ft], x86.REG_F0)
		if f.Op != gc.OREGISTER {
			if ft == gc.TFLOAT32 {
				gins(x86.AFMOVF, f, &r1)
			} else {
				gins(x86.AFMOVD, f, &r1)
			}
		}

		// set round to zero mode during conversion
		var t1 gc.Node
		memname(&t1, gc.Types[gc.TUINT16])

		var t2 gc.Node
		memname(&t2, gc.Types[gc.TUINT16])
		gins(x86.AFSTCW, nil, &t1)
		gins(x86.AMOVW, ncon(0xf7f), &t2)
		gins(x86.AFLDCW, &t2, nil)
		if tt == gc.TINT16 {
			gins(x86.AFMOVWP, &r1, t)
		} else if tt == gc.TINT32 {
			gins(x86.AFMOVLP, &r1, t)
		} else {
			gins(x86.AFMOVVP, &r1, t)
		}
		gins(x86.AFLDCW, &t1, nil)
		return

		// convert via int32.
	case gc.TFLOAT32<<16 | gc.TINT8,
		gc.TFLOAT32<<16 | gc.TUINT16,
		gc.TFLOAT32<<16 | gc.TUINT8,
		gc.TFLOAT64<<16 | gc.TINT8,
		gc.TFLOAT64<<16 | gc.TUINT16,
		gc.TFLOAT64<<16 | gc.TUINT8:
		var t1 gc.Node
		gc.Tempname(&t1, gc.Types[gc.TINT32])

		gmove(f, &t1)
		switch tt {
		default:
			gc.Fatal("gmove %v", gc.Nconv(t, 0))

		case gc.TINT8:
			gins(x86.ACMPL, &t1, ncon(-0x80&(1<<32-1)))
			p1 := gc.Gbranch(optoas(gc.OLT, gc.Types[gc.TINT32]), nil, -1)
			gins(x86.ACMPL, &t1, ncon(0x7f))
			p2 := gc.Gbranch(optoas(gc.OGT, gc.Types[gc.TINT32]), nil, -1)
			p3 := gc.Gbranch(obj.AJMP, nil, 0)
			gc.Patch(p1, gc.Pc)
			gc.Patch(p2, gc.Pc)
			gmove(ncon(-0x80&(1<<32-1)), &t1)
			gc.Patch(p3, gc.Pc)
			gmove(&t1, t)

		case gc.TUINT8:
			gins(x86.ATESTL, ncon(0xffffff00), &t1)
			p1 := gc.Gbranch(x86.AJEQ, nil, +1)
			gins(x86.AMOVL, ncon(0), &t1)
			gc.Patch(p1, gc.Pc)
			gmove(&t1, t)

		case gc.TUINT16:
			gins(x86.ATESTL, ncon(0xffff0000), &t1)
			p1 := gc.Gbranch(x86.AJEQ, nil, +1)
			gins(x86.AMOVL, ncon(0), &t1)
			gc.Patch(p1, gc.Pc)
			gmove(&t1, t)
		}

		return

		// convert via int64.
	case gc.TFLOAT32<<16 | gc.TUINT32,
		gc.TFLOAT64<<16 | gc.TUINT32:
//.........這裏部分代碼省略.........

//.........這裏部分代碼省略.........
		return

		/*
		 * integer to float
		 */
	case gc.TINT64<<16 | gc.TFLOAT32,
		gc.TINT64<<16 | gc.TFLOAT64:
		if t.Op == gc.OREGISTER {
			goto hardmem
		}
		var f0 gc.Node
		gc.Nodreg(&f0, t.Type, x86.REG_F0)
		gins(x86.AFMOVV, f, &f0)
		if tt == gc.TFLOAT32 {
			gins(x86.AFMOVFP, &f0, t)
		} else {
			gins(x86.AFMOVDP, &f0, t)
		}
		return

		// algorithm is:
	//	if small enough, use native int64 -> float64 conversion.
	//	otherwise, halve (rounding to odd?), convert, and double.
	case gc.TUINT64<<16 | gc.TFLOAT32,
		gc.TUINT64<<16 | gc.TFLOAT64:
		var ax gc.Node
		gc.Nodreg(&ax, gc.Types[gc.TUINT32], x86.REG_AX)

		var dx gc.Node
		gc.Nodreg(&dx, gc.Types[gc.TUINT32], x86.REG_DX)
		var cx gc.Node
		gc.Nodreg(&cx, gc.Types[gc.TUINT32], x86.REG_CX)
		var t1 gc.Node
		gc.Tempname(&t1, f.Type)
		var tlo gc.Node
		var thi gc.Node
		split64(&t1, &tlo, &thi)
		gmove(f, &t1)
		gins(x86.ACMPL, &thi, ncon(0))
		p1 := gc.Gbranch(x86.AJLT, nil, 0)

		// native
		var r1 gc.Node
		gc.Nodreg(&r1, gc.Types[tt], x86.REG_F0)

		gins(x86.AFMOVV, &t1, &r1)
		if tt == gc.TFLOAT32 {
			gins(x86.AFMOVFP, &r1, t)
		} else {
			gins(x86.AFMOVDP, &r1, t)
		}
		p2 := gc.Gbranch(obj.AJMP, nil, 0)

		// simulated
		gc.Patch(p1, gc.Pc)

		gmove(&tlo, &ax)
		gmove(&thi, &dx)
		p1 = gins(x86.ASHRL, ncon(1), &ax)
		p1.From.Index = x86.REG_DX // double-width shift DX -> AX
		p1.From.Scale = 0
		gins(x86.AMOVL, ncon(0), &cx)
		gins(x86.ASETCC, nil, &cx)
		gins(x86.AORL, &cx, &ax)
		gins(x86.ASHRL, ncon(1), &dx)
		gmove(&dx, &thi)

func igenindex(n *gc.Node, res *gc.Node, bounded bool) *obj.Prog {
	gc.Tempname(res, n.Type)
	return cgenindex(n, res, bounded)
}

func cgen_floatsse(n *gc.Node, res *gc.Node) {
	var a int

	nl := n.Left
	nr := n.Right
	switch n.Op {
	default:
		gc.Dump("cgen_floatsse", n)
		gc.Fatal("cgen_floatsse %v", gc.Oconv(int(n.Op), 0))
		return

	case gc.OMINUS,
		gc.OCOM:
		nr = gc.Nodintconst(-1)
		gc.Convlit(&nr, n.Type)
		a = foptoas(gc.OMUL, nl.Type, 0)
		goto sbop

		// symmetric binary
	case gc.OADD,
		gc.OMUL:
		a = foptoas(int(n.Op), nl.Type, 0)

		goto sbop

		// asymmetric binary
	case gc.OSUB,
		gc.OMOD,
		gc.ODIV:
		a = foptoas(int(n.Op), nl.Type, 0)

		goto abop
	}

sbop: // symmetric binary
	if nl.Ullman < nr.Ullman || nl.Op == gc.OLITERAL {
		r := nl
		nl = nr
		nr = r
	}

abop: // asymmetric binary
	if nl.Ullman >= nr.Ullman {
		var nt gc.Node
		gc.Tempname(&nt, nl.Type)
		gc.Cgen(nl, &nt)
		var n2 gc.Node
		gc.Mgen(nr, &n2, nil)
		var n1 gc.Node
		gc.Regalloc(&n1, nl.Type, res)
		gmove(&nt, &n1)
		gins(a, &n2, &n1)
		gmove(&n1, res)
		gc.Regfree(&n1)
		gc.Mfree(&n2)
	} else {
		var n2 gc.Node
		gc.Regalloc(&n2, nr.Type, res)
		gc.Cgen(nr, &n2)
		var n1 gc.Node
		gc.Regalloc(&n1, nl.Type, nil)
		gc.Cgen(nl, &n1)
		gins(a, &n2, &n1)
		gc.Regfree(&n2)
		gmove(&n1, res)
		gc.Regfree(&n1)
	}

	return
}

/*
 * generate shift according to op, one of:
 *	res = nl << nr
 *	res = nl >> nr
 */
func cgen_shift(op int, bounded bool, nl *gc.Node, nr *gc.Node, res *gc.Node) {
	a := int(optoas(op, nl.Type))

	if nr.Op == gc.OLITERAL {
		var n1 gc.Node
		regalloc(&n1, nl.Type, res)
		cgen(nl, &n1)
		sc := uint64(uint64(gc.Mpgetfix(nr.Val.U.Xval)))
		if sc >= uint64(nl.Type.Width*8) {
			// large shift gets 2 shifts by width-1
			var n3 gc.Node
			gc.Nodconst(&n3, gc.Types[gc.TUINT32], nl.Type.Width*8-1)

			gins(a, &n3, &n1)
			gins(a, &n3, &n1)
		} else {
			gins(a, nr, &n1)
		}
		gmove(&n1, res)
		regfree(&n1)
		return
	}

	if nl.Ullman >= gc.UINF {
		var n4 gc.Node
		gc.Tempname(&n4, nl.Type)
		cgen(nl, &n4)
		nl = &n4
	}

	if nr.Ullman >= gc.UINF {
		var n5 gc.Node
		gc.Tempname(&n5, nr.Type)
		cgen(nr, &n5)
		nr = &n5
	}

	// Allow either uint32 or uint64 as shift type,
	// to avoid unnecessary conversion from uint32 to uint64
	// just to do the comparison.
	tcount := gc.Types[gc.Simtype[nr.Type.Etype]]

	if tcount.Etype < gc.TUINT32 {
		tcount = gc.Types[gc.TUINT32]
	}

	var n1 gc.Node
	regalloc(&n1, nr.Type, nil) // to hold the shift type in CX
	var n3 gc.Node
	regalloc(&n3, tcount, &n1) // to clear high bits of CX

	var n2 gc.Node
	regalloc(&n2, nl.Type, res)

	if nl.Ullman >= nr.Ullman {
		cgen(nl, &n2)
		cgen(nr, &n1)
		gmove(&n1, &n3)
	} else {
		cgen(nr, &n1)
		gmove(&n1, &n3)
		cgen(nl, &n2)
	}

	regfree(&n3)

	// test and fix up large shifts
	if !bounded {
		gc.Nodconst(&n3, tcount, nl.Type.Width*8)
		gins(optoas(gc.OCMP, tcount), &n1, &n3)
		p1 := (*obj.Prog)(gc.Gbranch(optoas(gc.OLT, tcount), nil, +1))
		if op == gc.ORSH && gc.Issigned[nl.Type.Etype] {
			gc.Nodconst(&n3, gc.Types[gc.TUINT32], nl.Type.Width*8-1)
			gins(a, &n3, &n2)
		} else {
			gc.Nodconst(&n3, nl.Type, 0)
			gmove(&n3, &n2)
		}

		gc.Patch(p1, gc.Pc)
	}

	gins(a, &n1, &n2)

	gmove(&n2, res)

	regfree(&n1)
	regfree(&n2)
}