Golang obj.Prog類代碼示例

func zerorange(p *obj.Prog, frame int64, lo int64, hi int64) *obj.Prog {
	cnt := hi - lo
	if cnt == 0 {
		return p
	}
	if cnt < int64(4*gc.Widthptr) {
		for i := int64(0); i < cnt; i += int64(gc.Widthptr) {
			p = appendpp(p, ppc64.AMOVD, obj.TYPE_REG, ppc64.REGZERO, 0, obj.TYPE_MEM, ppc64.REGSP, gc.Ctxt.FixedFrameSize()+frame+lo+i)
		}
	} else if cnt <= int64(128*gc.Widthptr) {
		p = appendpp(p, ppc64.AADD, obj.TYPE_CONST, 0, gc.Ctxt.FixedFrameSize()+frame+lo-8, obj.TYPE_REG, ppc64.REGRT1, 0)
		p.Reg = ppc64.REGSP
		p = appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
		f := gc.Sysfunc("duffzero")
		gc.Naddr(&p.To, f)
		gc.Afunclit(&p.To, f)
		p.To.Offset = 4 * (128 - cnt/int64(gc.Widthptr))
	} else {
		p = appendpp(p, ppc64.AMOVD, obj.TYPE_CONST, 0, gc.Ctxt.FixedFrameSize()+frame+lo-8, obj.TYPE_REG, ppc64.REGTMP, 0)
		p = appendpp(p, ppc64.AADD, obj.TYPE_REG, ppc64.REGTMP, 0, obj.TYPE_REG, ppc64.REGRT1, 0)
		p.Reg = ppc64.REGSP
		p = appendpp(p, ppc64.AMOVD, obj.TYPE_CONST, 0, cnt, obj.TYPE_REG, ppc64.REGTMP, 0)
		p = appendpp(p, ppc64.AADD, obj.TYPE_REG, ppc64.REGTMP, 0, obj.TYPE_REG, ppc64.REGRT2, 0)
		p.Reg = ppc64.REGRT1
		p = appendpp(p, ppc64.AMOVDU, obj.TYPE_REG, ppc64.REGZERO, 0, obj.TYPE_MEM, ppc64.REGRT1, int64(gc.Widthptr))
		p1 := p
		p = appendpp(p, ppc64.ACMP, obj.TYPE_REG, ppc64.REGRT1, 0, obj.TYPE_REG, ppc64.REGRT2, 0)
		p = appendpp(p, ppc64.ABNE, obj.TYPE_NONE, 0, 0, obj.TYPE_BRANCH, 0, 0)
		gc.Patch(p, p1)
	}

	return p
}

func Prog(as obj.As) *obj.Prog {
	var p *obj.Prog

	if as == obj.AGLOBL {
		if ddumped {
			Fatalf("already dumped data")
		}
		if dpc == nil {
			dpc = Ctxt.NewProg()
			dfirst = dpc
		}

		p = dpc
		dpc = Ctxt.NewProg()
		p.Link = dpc
	} else {
		p = Pc
		Pc = Ctxt.NewProg()
		Clearp(Pc)
		p.Link = Pc
	}

	if lineno == 0 && Debug['K'] != 0 {
		Warn("prog: line 0")
	}

	p.As = as
	p.Lineno = lineno
	return p
}

// 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
	var p2 *obj.Prog

	for p := firstp; p != nil; p = p.Link {
		if p.As != obj.ACHECKNIL {
			continue
		}
		if gc.Debug_checknil != 0 && p.Lineno > 1 { // p->lineno==1 in generated wrappers
			gc.Warnl(p.Lineno, "generated nil check")
		}

		// check is
		//	CMP arg, $0
		//	JNE 2(PC) (likely)
		//	MOV AX, 0
		p1 = gc.Ctxt.NewProg()

		p2 = gc.Ctxt.NewProg()
		gc.Clearp(p1)
		gc.Clearp(p2)
		p1.Link = p2
		p2.Link = p.Link
		p.Link = p1
		p1.Lineno = p.Lineno
		p2.Lineno = p.Lineno
		p1.Pc = 9999
		p2.Pc = 9999
		p.As = cmpptr
		p.To.Type = obj.TYPE_CONST
		p.To.Offset = 0
		p1.As = x86.AJNE
		p1.From.Type = obj.TYPE_CONST
		p1.From.Offset = 1 // likely
		p1.To.Type = obj.TYPE_BRANCH
		p1.To.Val = p2.Link

		// crash by write to memory address 0.
		// if possible, since we know arg is 0, use 0(arg),
		// which will be shorter to encode than plain 0.
		p2.As = x86.AMOVL

		p2.From.Type = obj.TYPE_REG
		p2.From.Reg = x86.REG_AX
		if regtyp(&p.From) {
			p2.To.Type = obj.TYPE_MEM
			p2.To.Reg = p.From.Reg
		} else {
			p2.To.Type = obj.TYPE_MEM
			p2.To.Reg = x86.REG_NONE
		}

		p2.To.Offset = 0
	}
}

/*
 * 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", n.Op)
		} else {
			gc.Fatalf("bad in raddr: <null>")
		}
		p.Reg = 0
	} else {
		p.Reg = a.Reg
	}
}

/*
 * generate high multiply
 *  res = (nl * nr) >> wordsize
 */
func cgen_hmul(nl *gc.Node, nr *gc.Node, res *gc.Node) {
	if nl.Ullman < nr.Ullman {
		nl, nr = nr, nl
	}

	t := nl.Type
	w := t.Width * 8
	var n1 gc.Node
	gc.Regalloc(&n1, t, res)
	gc.Cgen(nl, &n1)
	var n2 gc.Node
	gc.Regalloc(&n2, t, nil)
	gc.Cgen(nr, &n2)
	switch gc.Simtype[t.Etype] {
	case gc.TINT8,
		gc.TINT16:
		gins(optoas(gc.OMUL, t), &n2, &n1)
		gshift(arm.AMOVW, &n1, arm.SHIFT_AR, int32(w), &n1)

	case gc.TUINT8,
		gc.TUINT16:
		gins(optoas(gc.OMUL, t), &n2, &n1)
		gshift(arm.AMOVW, &n1, arm.SHIFT_LR, int32(w), &n1)

		// perform a long multiplication.
	case gc.TINT32,
		gc.TUINT32:
		var p *obj.Prog
		if t.IsSigned() {
			p = gins(arm.AMULL, &n2, nil)
		} else {
			p = gins(arm.AMULLU, &n2, nil)
		}

		// n2 * n1 -> (n1 n2)
		p.Reg = n1.Reg

		p.To.Type = obj.TYPE_REGREG
		p.To.Reg = n1.Reg
		p.To.Offset = int64(n2.Reg)

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

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

func rewriteToPcrel(ctxt *obj.Link, p *obj.Prog) {
	// RegTo2 is set on the instructions we insert here so they don't get
	// processed twice.
	if p.RegTo2 != 0 {
		return
	}
	if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
		return
	}
	// Any Prog (aside from the above special cases) with an Addr with Name ==
	// NAME_EXTERN, NAME_STATIC or NAME_GOTREF has a CALL __x86.get_pc_thunk.cx
	// inserted before it.
	isName := func(a *obj.Addr) bool {
		if a.Sym == nil || (a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR) || a.Reg != 0 {
			return false
		}
		if a.Sym.Type == obj.STLSBSS {
			return false
		}
		return a.Name == obj.NAME_EXTERN || a.Name == obj.NAME_STATIC || a.Name == obj.NAME_GOTREF
	}

	if isName(&p.From) && p.From.Type == obj.TYPE_ADDR {
		// Handle things like "MOVL $sym, (SP)" or "PUSHL $sym" by rewriting
		// to "MOVL $sym, CX; MOVL CX, (SP)" or "MOVL $sym, CX; PUSHL CX"
		// respectively.
		if p.To.Type != obj.TYPE_REG {
			q := obj.Appendp(ctxt, p)
			q.As = p.As
			q.From.Type = obj.TYPE_REG
			q.From.Reg = REG_CX
			q.To = p.To
			p.As = AMOVL
			p.To.Type = obj.TYPE_REG
			p.To.Reg = REG_CX
			p.To.Sym = nil
			p.To.Name = obj.NAME_NONE
		}
	}

	if !isName(&p.From) && !isName(&p.To) && (p.From3 == nil || !isName(p.From3)) {
		return
	}
	q := obj.Appendp(ctxt, p)
	q.RegTo2 = 1
	r := obj.Appendp(ctxt, q)
	r.RegTo2 = 1
	q.As = obj.ACALL
	q.To.Sym = obj.Linklookup(ctxt, "__x86.get_pc_thunk.cx", 0)
	q.To.Type = obj.TYPE_MEM
	q.To.Name = obj.NAME_EXTERN
	q.To.Sym.Local = true
	r.As = p.As
	r.Scond = p.Scond
	r.From = p.From
	r.From3 = p.From3
	r.Reg = p.Reg
	r.To = p.To
	obj.Nopout(p)
}

func stacksplitPost(ctxt *obj.Link, p *obj.Prog, pPre *obj.Prog, pPreempt *obj.Prog) *obj.Prog {

	// MOVD	LR, R5
	p = obj.Appendp(ctxt, p)
	pPre.Pcond = p
	p.As = AMOVD
	p.From.Type = obj.TYPE_REG
	p.From.Reg = REG_LR
	p.To.Type = obj.TYPE_REG
	p.To.Reg = REG_R5
	if pPreempt != nil {
		pPreempt.Pcond = p
	}

	// BL	runtime.morestack(SB)
	p = obj.Appendp(ctxt, p)

	p.As = ABL
	p.To.Type = obj.TYPE_BRANCH
	if ctxt.Cursym.Cfunc {
		p.To.Sym = obj.Linklookup(ctxt, "runtime.morestackc", 0)
	} else if ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0 {
		p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
	} else {
		p.To.Sym = obj.Linklookup(ctxt, "runtime.morestack", 0)
	}

	// BR	start
	p = obj.Appendp(ctxt, p)

	p.As = ABR
	p.To.Type = obj.TYPE_BRANCH
	p.Pcond = ctxt.Cursym.Text.Link
	return p
}

/*
 * The idea is to remove redundant constants.
 *	$c1->v1
 *	($c1->v2 s/$c1/v1)*
 *	set v1  return
 * The v1->v2 should be eliminated by copy propagation.
 */
func constprop(c1 *obj.Addr, v1 *obj.Addr, r *gc.Flow) {
	if gc.Debug['P'] != 0 {
		fmt.Printf("constprop %v->%v\n", gc.Ctxt.Dconv(c1), gc.Ctxt.Dconv(v1))
	}
	var p *obj.Prog
	for ; r != nil; r = r.S1 {
		p = r.Prog
		if gc.Debug['P'] != 0 {
			fmt.Printf("%v", p)
		}
		if gc.Uniqp(r) == nil {
			if gc.Debug['P'] != 0 {
				fmt.Printf("; merge; return\n")
			}
			return
		}

		if p.As == arm.AMOVW && copyas(&p.From, c1) {
			if gc.Debug['P'] != 0 {
				fmt.Printf("; sub%v/%v", gc.Ctxt.Dconv(&p.From), gc.Ctxt.Dconv(v1))
			}
			p.From = *v1
		} else if copyu(p, v1, nil) > 1 {
			if gc.Debug['P'] != 0 {
				fmt.Printf("; %vset; return\n", gc.Ctxt.Dconv(v1))
			}
			return
		}

		if gc.Debug['P'] != 0 {
			fmt.Printf("\n")
		}
		if r.S2 != nil {
			constprop(c1, v1, r.S2)
		}
	}
}

func appendpp(p *obj.Prog, as obj.As, ftype obj.AddrType, freg int, foffset int32, ttype obj.AddrType, treg int, toffset int32) *obj.Prog {
	q := gc.Ctxt.NewProg()
	gc.Clearp(q)
	q.As = as
	q.Lineno = p.Lineno
	q.From.Type = ftype
	q.From.Reg = int16(freg)
	q.From.Offset = int64(foffset)
	q.To.Type = ttype
	q.To.Reg = int16(treg)
	q.To.Offset = int64(toffset)
	q.Link = p.Link
	p.Link = q
	return q
}

func addnop(ctxt *obj.Link, p *obj.Prog) {
	q := ctxt.NewProg()
	// we want to use the canonical NOP (SLL $0,R0,R0) here,
	// however, as the assembler will always replace $0
	// as R0, we have to resort to manually encode the SLL
	// instruction as WORD $0.
	q.As = AWORD
	q.Lineno = p.Lineno
	q.From.Type = obj.TYPE_CONST
	q.From.Name = obj.NAME_NONE
	q.From.Offset = 0

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

func oplook(ctxt *obj.Link, p *obj.Prog) *Optab {
	if oprange[AOR&obj.AMask] == nil {
		buildop(ctxt)
	}

	a1 := int(p.Optab)
	if a1 != 0 {
		return &optab[a1-1]
	}
	a1 = int(p.From.Class)
	if a1 == 0 {
		a1 = aclass(ctxt, &p.From) + 1
		p.From.Class = int8(a1)
	}

	a1--
	a3 := int(p.To.Class)
	if a3 == 0 {
		a3 = aclass(ctxt, &p.To) + 1
		p.To.Class = int8(a3)
	}

	a3--
	a2 := C_NONE
	if p.Reg != 0 {
		a2 = C_REG
	}

	//print("oplook %P %d %d %d\n", p, a1, a2, a3);

	ops := oprange[p.As&obj.AMask]
	c1 := &xcmp[a1]
	c3 := &xcmp[a3]
	for i := range ops {
		op := &ops[i]
		if int(op.a2) == a2 && c1[op.a1] && c3[op.a3] {
			p.Optab = uint16(cap(optab) - cap(ops) + i + 1)
			return op
		}
	}

	ctxt.Diag("illegal combination %v %v %v %v", obj.Aconv(p.As), DRconv(a1), DRconv(a2), DRconv(a3))
	prasm(p)
	if ops == nil {
		ops = optab
	}
	return &ops[0]
}

// movb elimination.
// movb is simulated by the linker
// when a register other than ax, bx, cx, dx
// is used, so rewrite to other instructions
// when possible.  a movb into a register
// can smash the entire 64-bit register without
// causing any trouble.
func elimshortmov(g *gc.Graph) {
	var p *obj.Prog

	for r := g.Start; r != nil; r = r.Link {
		p = r.Prog
		if regtyp(&p.To) {
			switch p.As {
			case x86.AINCB,
				x86.AINCW:
				p.As = x86.AINCL

			case x86.ADECB,
				x86.ADECW:
				p.As = x86.ADECL

			case x86.ANEGB,
				x86.ANEGW:
				p.As = x86.ANEGL

			case x86.ANOTB,
				x86.ANOTW:
				p.As = x86.ANOTL
			}

			if regtyp(&p.From) || p.From.Type == obj.TYPE_CONST {
				// move or arithmetic into partial register.
				// from another register or constant can be movl.
				// we don't switch to 32-bit arithmetic if it can
				// change how the carry bit is set (and the carry bit is needed).
				switch p.As {
				case x86.AMOVB,
					x86.AMOVW:
					p.As = x86.AMOVL

				case x86.AADDB,
					x86.AADDW:
					if !needc(p.Link) {
						p.As = x86.AADDL
					}

				case x86.ASUBB,
					x86.ASUBW:
					if !needc(p.Link) {
						p.As = x86.ASUBL
					}

				case x86.AMULB,
					x86.AMULW:
					p.As = x86.AMULL

				case x86.AIMULB,
					x86.AIMULW:
					p.As = x86.AIMULL

				case x86.AANDB,
					x86.AANDW:
					p.As = x86.AANDL

				case x86.AORB,
					x86.AORW:
					p.As = x86.AORL

				case x86.AXORB,
					x86.AXORW:
					p.As = x86.AXORL

				case x86.ASHLB,
					x86.ASHLW:
					p.As = x86.ASHLL
				}
			} else {
				// explicit zero extension
				switch p.As {
				case x86.AMOVB:
					p.As = x86.AMOVBLZX

				case x86.AMOVW:
					p.As = x86.AMOVWLZX
				}
			}
		}
	}
}

func Clearp(p *obj.Prog) {
	obj.Nopout(p)
	p.As = obj.AEND
	p.Pc = int64(pcloc)
	pcloc++
}

func peep(firstp *obj.Prog) {
	g := gc.Flowstart(firstp, nil)
	if g == nil {
		return
	}
	gactive = 0

	var p *obj.Prog
	var r *gc.Flow
	var t obj.As
loop1:
	if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
		gc.Dumpit("loop1", g.Start, 0)
	}

	t = 0
	for r = g.Start; r != nil; r = r.Link {
		p = r.Prog

		// TODO(austin) Handle smaller moves.  arm and amd64
		// distinguish between moves that moves that *must*
		// sign/zero extend and moves that don't care so they
		// can eliminate moves that don't care without
		// breaking moves that do care. This might let us
		// simplify or remove the next peep loop, too.
		if p.As == ppc64.AMOVD || p.As == ppc64.AFMOVD {
			if regtyp(&p.To) {
				// Try to eliminate reg->reg moves
				if regtyp(&p.From) {
					if p.From.Type == p.To.Type {
						if copyprop(r) {
							excise(r)
							t++
						} else if subprop(r) && copyprop(r) {
							excise(r)
							t++
						}
					}
				}

				// Convert uses to $0 to uses of R0 and
				// propagate R0
				if regzer(&p.From) {
					if p.To.Type == obj.TYPE_REG {
						p.From.Type = obj.TYPE_REG
						p.From.Reg = ppc64.REGZERO
						if copyprop(r) {
							excise(r)
							t++
						} else if subprop(r) && copyprop(r) {
							excise(r)
							t++
						}
					}
				}
			}
		}
	}

	if t != 0 {
		goto loop1
	}

	/*
	 * look for MOVB x,R; MOVB R,R (for small MOVs not handled above)
	 */
	var p1 *obj.Prog
	var r1 *gc.Flow
	for r := g.Start; r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		default:
			continue

		case ppc64.AMOVH,
			ppc64.AMOVHZ,
			ppc64.AMOVB,
			ppc64.AMOVBZ,
			ppc64.AMOVW,
			ppc64.AMOVWZ:
			if p.To.Type != obj.TYPE_REG {
				continue
			}
		}

		r1 = r.Link
		if r1 == nil {
			continue
		}
		p1 = r1.Prog
		if p1.As != p.As {
			continue
		}
		if p1.From.Type != obj.TYPE_REG || p1.From.Reg != p.To.Reg {
			continue
		}
		if p1.To.Type != obj.TYPE_REG || p1.To.Reg != p.To.Reg {
			continue
		}
		excise(r1)
//.........這裏部分代碼省略.........

func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) {
	var q *obj.Prog
	var r *obj.Prog
	var i int

loop:
	if p == nil {
		return
	}
	a := p.As
	if a == AB {
		q = p.Pcond
		if q != nil && q.As != obj.ATEXT {
			p.Mark |= FOLL
			p = q
			if p.Mark&FOLL == 0 {
				goto loop
			}
		}
	}

	if p.Mark&FOLL != 0 {
		i = 0
		q = p
		for ; i < 4; i, q = i+1, q.Link {
			if q == *last || q == nil {
				break
			}
			a = q.As
			if a == obj.ANOP {
				i--
				continue
			}

			if a == AB || (a == obj.ARET && q.Scond == C_SCOND_NONE) || a == ARFE || a == obj.AUNDEF {
				goto copy
			}
			if q.Pcond == nil || (q.Pcond.Mark&FOLL != 0) {
				continue
			}
			if a != ABEQ && a != ABNE {
				continue
			}

		copy:
			for {
				r = ctxt.NewProg()
				*r = *p
				if r.Mark&FOLL == 0 {
					fmt.Printf("can't happen 1\n")
				}
				r.Mark |= FOLL
				if p != q {
					p = p.Link
					(*last).Link = r
					*last = r
					continue
				}

				(*last).Link = r
				*last = r
				if a == AB || (a == obj.ARET && q.Scond == C_SCOND_NONE) || a == ARFE || a == obj.AUNDEF {
					return
				}
				r.As = ABNE
				if a == ABNE {
					r.As = ABEQ
				}
				r.Pcond = p.Link
				r.Link = p.Pcond
				if r.Link.Mark&FOLL == 0 {
					xfol(ctxt, r.Link, last)
				}
				if r.Pcond.Mark&FOLL == 0 {
					fmt.Printf("can't happen 2\n")
				}
				return
			}
		}

		a = AB
		q = ctxt.NewProg()
		q.As = a
		q.Lineno = p.Lineno
		q.To.Type = obj.TYPE_BRANCH
		q.To.Offset = p.Pc
		q.Pcond = p
		p = q
	}

	p.Mark |= FOLL
	(*last).Link = p
	*last = p
	if a == AB || (a == obj.ARET && p.Scond == C_SCOND_NONE) || a == ARFE || a == obj.AUNDEF {
		return
	}

	if p.Pcond != nil {
		if a != ABL && a != ABX && p.Link != nil {
			q = obj.Brchain(ctxt, p.Link)
//.........這裏部分代碼省略.........