Golang Node.Addable方法代碼示例

/*
 * call to n has already been generated.
 * generate:
 *	res = &return value from call.
 */
func cgen_aret(n *gc.Node, res *gc.Node) {
	t := n.Left.Type
	if gc.Isptr[t.Etype] {
		t = t.Type
	}

	var flist gc.Iter
	fp := gc.Structfirst(&flist, gc.Getoutarg(t))
	if fp == nil {
		gc.Fatal("cgen_aret: nil")
	}

	var nod1 gc.Node
	nod1.Op = gc.OINDREG
	nod1.Val.U.Reg = x86.REG_SP
	nod1.Addable = 1

	nod1.Xoffset = fp.Width
	nod1.Type = fp.Type

	if res.Op != gc.OREGISTER {
		var nod2 gc.Node
		regalloc(&nod2, gc.Types[gc.Tptr], res)
		gins(x86.ALEAL, &nod1, &nod2)
		gins(x86.AMOVL, &nod2, res)
		regfree(&nod2)
	} else {
		gins(x86.ALEAL, &nod1, res)
	}
}

/*
 * call to n has already been generated.
 * generate:
 *	res = return value from call.
 */
func cgen_callret(n *gc.Node, res *gc.Node) {
	t := n.Left.Type
	if t.Etype == gc.TPTR32 || t.Etype == gc.TPTR64 {
		t = t.Type
	}

	var flist gc.Iter
	fp := gc.Structfirst(&flist, gc.Getoutarg(t))
	if fp == nil {
		gc.Fatal("cgen_callret: nil")
	}

	var nod gc.Node
	nod.Op = gc.OINDREG
	nod.Val.U.Reg = x86.REG_SP
	nod.Addable = 1

	nod.Xoffset = fp.Width
	nod.Type = fp.Type
	gc.Cgen_as(res, &nod)
}

/*
 * generate:
 *	res = n;
 * simplifies and calls gmove.
 */
func cgen(n *gc.Node, res *gc.Node) {
	//print("cgen %N(%d) -> %N(%d)\n", n, n->addable, res, res->addable);
	if gc.Debug['g'] != 0 {
		gc.Dump("\ncgen-n", n)
		gc.Dump("cgen-res", res)
	}

	if n == nil || n.Type == nil {
		return
	}

	if res == nil || res.Type == nil {
		gc.Fatal("cgen: res nil")
	}

	for n.Op == gc.OCONVNOP {
		n = n.Left
	}

	switch n.Op {
	case gc.OSLICE,
		gc.OSLICEARR,
		gc.OSLICESTR,
		gc.OSLICE3,
		gc.OSLICE3ARR:
		if res.Op != gc.ONAME || res.Addable == 0 {
			var n1 gc.Node
			gc.Tempname(&n1, n.Type)
			gc.Cgen_slice(n, &n1)
			cgen(&n1, res)
		} else {
			gc.Cgen_slice(n, res)
		}
		return

	case gc.OEFACE:
		if res.Op != gc.ONAME || res.Addable == 0 {
			var n1 gc.Node
			gc.Tempname(&n1, n.Type)
			gc.Cgen_eface(n, &n1)
			cgen(&n1, res)
		} else {
			gc.Cgen_eface(n, res)
		}
		return
	}

	if n.Ullman >= gc.UINF {
		if n.Op == gc.OINDREG {
			gc.Fatal("cgen: this is going to misscompile")
		}
		if res.Ullman >= gc.UINF {
			var n1 gc.Node
			gc.Tempname(&n1, n.Type)
			cgen(n, &n1)
			cgen(&n1, res)
			return
		}
	}

	if gc.Isfat(n.Type) {
		if n.Type.Width < 0 {
			gc.Fatal("forgot to compute width for %v", gc.Tconv(n.Type, 0))
		}
		sgen(n, res, n.Type.Width)
		return
	}

	if res.Addable == 0 {
		if n.Ullman > res.Ullman {
			var n1 gc.Node
			regalloc(&n1, n.Type, res)
			cgen(n, &n1)
			if n1.Ullman > res.Ullman {
				gc.Dump("n1", &n1)
				gc.Dump("res", res)
				gc.Fatal("loop in cgen")
			}

			cgen(&n1, res)
			regfree(&n1)
			return
		}

		var f int
		if res.Ullman >= gc.UINF {
			goto gen
		}

		if gc.Complexop(n, res) {
			gc.Complexgen(n, res)
			return
		}

		f = 1 // gen thru register
//.........這裏部分代碼省略.........

/*
 * generate:
 *	newreg = &n;
 *	res = newreg
 *
 * on exit, a has been changed to be *newreg.
 * caller must regfree(a).
 * The generated code checks that the result is not *nil.
 */
func igen(n *gc.Node, a *gc.Node, res *gc.Node) {
	if gc.Debug['g'] != 0 {
		gc.Dump("\nigen-n", n)
	}

	switch n.Op {
	case gc.ONAME:
		if (n.Class&gc.PHEAP != 0) || n.Class == gc.PPARAMREF {
			break
		}
		*a = *n
		return

		// Increase the refcount of the register so that igen's caller
	// has to call regfree.
	case gc.OINDREG:
		if n.Val.U.Reg != ppc64.REGSP {
			reg[n.Val.U.Reg]++
		}
		*a = *n
		return

	case gc.ODOT:
		igen(n.Left, a, res)
		a.Xoffset += n.Xoffset
		a.Type = n.Type
		fixlargeoffset(a)
		return

	case gc.ODOTPTR:
		cgenr(n.Left, a, res)
		gc.Cgen_checknil(a)
		a.Op = gc.OINDREG
		a.Xoffset += n.Xoffset
		a.Type = n.Type
		fixlargeoffset(a)
		return

	case gc.OCALLFUNC,
		gc.OCALLMETH,
		gc.OCALLINTER:
		switch n.Op {
		case gc.OCALLFUNC:
			cgen_call(n, 0)

		case gc.OCALLMETH:
			gc.Cgen_callmeth(n, 0)

		case gc.OCALLINTER:
			cgen_callinter(n, nil, 0)
		}

		var flist gc.Iter
		fp := gc.Structfirst(&flist, gc.Getoutarg(n.Left.Type))
		*a = gc.Node{}
		a.Op = gc.OINDREG
		a.Val.U.Reg = ppc64.REGSP
		a.Addable = 1
		a.Xoffset = fp.Width + int64(gc.Widthptr) // +widthptr: saved lr at 0(SP)
		a.Type = n.Type
		return

		// Index of fixed-size array by constant can
	// put the offset in the addressing.
	// Could do the same for slice except that we need
	// to use the real index for the bounds checking.
	case gc.OINDEX:
		if gc.Isfixedarray(n.Left.Type) || (gc.Isptr[n.Left.Type.Etype] && gc.Isfixedarray(n.Left.Left.Type)) {
			if gc.Isconst(n.Right, gc.CTINT) {
				// Compute &a.
				if !gc.Isptr[n.Left.Type.Etype] {
					igen(n.Left, a, res)
				} else {
					var n1 gc.Node
					igen(n.Left, &n1, res)
					gc.Cgen_checknil(&n1)
					regalloc(a, gc.Types[gc.Tptr], res)
					gmove(&n1, a)
					regfree(&n1)
					a.Op = gc.OINDREG
				}

				// Compute &a[i] as &a + i*width.
				a.Type = n.Type

				a.Xoffset += gc.Mpgetfix(n.Right.Val.U.Xval) * n.Type.Width
				fixlargeoffset(a)
				return
			}
		}
	}
//.........這裏部分代碼省略.........