Golang Addr.Reg方法代码示例

func nacladdr(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) {
	if p.As == ALEAL || p.As == ALEAQ {
		return
	}

	if a.Reg == REG_BP {
		ctxt.Diag("invalid address: %v", p)
		return
	}

	if a.Reg == REG_TLS {
		a.Reg = REG_BP
	}
	if a.Type == obj.TYPE_MEM && a.Name == obj.NAME_NONE {
		switch a.Reg {
		// all ok
		case REG_BP, REG_SP, REG_R15:
			break

		default:
			if a.Index != REG_NONE {
				ctxt.Diag("invalid address %v", p)
			}
			a.Index = a.Reg
			if a.Index != REG_NONE {
				a.Scale = 1
			}
			a.Reg = REG_R15
		}
	}
}

func addreg(a *obj.Addr, rn int) {
	a.Sym = nil
	a.Node = nil
	a.Offset = 0
	a.Type = obj.TYPE_REG
	a.Reg = int16(rn)
	a.Name = 0

	Ostats.Ncvtreg++
}

/*
 * substitute s for v in a
 * return failure to substitute
 */
func copysub(a *obj.Addr, v *obj.Addr, s *obj.Addr, f int) int {
	if copyas(a, v) {
		reg := int(int(s.Reg))
		if reg >= x86.REG_AX && reg <= x86.REG_R15 || reg >= x86.REG_X0 && reg <= x86.REG_X0+15 {
			if f != 0 {
				a.Reg = int16(reg)
			}
		}

		return 0
	}

	if regtyp(v) {
		reg := int(int(v.Reg))
		if a.Type == obj.TYPE_MEM && int(a.Reg) == reg {
			if (s.Reg == x86.REG_BP || s.Reg == x86.REG_R13) && a.Index != x86.REG_NONE {
				return 1 /* can't use BP-base with index */
			}
			if f != 0 {
				a.Reg = s.Reg
			}
		}

		//			return 0;
		if int(a.Index) == reg {
			if f != 0 {
				a.Index = s.Reg
			}
			return 0
		}

		return 0
	}

	return 0
}

// Naddr rewrites a to refer to n.
// It assumes that a is zeroed on entry.
func Naddr(a *obj.Addr, n *Node) {
	if n == nil {
		return
	}

	if n.Type != nil && n.Type.Etype != TIDEAL {
		// TODO(rsc): This is undone by the selective clearing of width below,
		// to match architectures that were not as aggressive in setting width
		// during naddr. Those widths must be cleared to avoid triggering
		// failures in gins when it detects real but heretofore latent (and one
		// hopes innocuous) type mismatches.
		// The type mismatches should be fixed and the clearing below removed.
		dowidth(n.Type)

		a.Width = n.Type.Width
	}

	switch n.Op {
	default:
		a := a // copy to let escape into Ctxt.Dconv
		Debug['h'] = 1
		Dump("naddr", n)
		Fatal("naddr: bad %v %v", Oconv(int(n.Op), 0), Ctxt.Dconv(a))

	case OREGISTER:
		a.Type = obj.TYPE_REG
		a.Reg = n.Reg
		a.Sym = nil
		if Thearch.Thechar == '8' { // TODO(rsc): Never clear a->width.
			a.Width = 0
		}

	case OINDREG:
		a.Type = obj.TYPE_MEM
		a.Reg = n.Reg
		a.Sym = Linksym(n.Sym)
		a.Offset = n.Xoffset
		if a.Offset != int64(int32(a.Offset)) {
			Yyerror("offset %d too large for OINDREG", a.Offset)
		}
		if Thearch.Thechar == '8' { // TODO(rsc): Never clear a->width.
			a.Width = 0
		}

		// n->left is PHEAP ONAME for stack parameter.
	// compute address of actual parameter on stack.
	case OPARAM:
		a.Etype = Simtype[n.Left.Type.Etype]

		a.Width = n.Left.Type.Width
		a.Offset = n.Xoffset
		a.Sym = Linksym(n.Left.Sym)
		a.Type = obj.TYPE_MEM
		a.Name = obj.NAME_PARAM
		a.Node = n.Left.Orig

	case OCLOSUREVAR:
		if !Curfn.Func.Needctxt {
			Fatal("closurevar without needctxt")
		}
		a.Type = obj.TYPE_MEM
		a.Reg = int16(Thearch.REGCTXT)
		a.Sym = nil
		a.Offset = n.Xoffset

	case OCFUNC:
		Naddr(a, n.Left)
		a.Sym = Linksym(n.Left.Sym)

	case ONAME:
		a.Etype = 0
		if n.Type != nil {
			a.Etype = Simtype[n.Type.Etype]
		}
		a.Offset = n.Xoffset
		s := n.Sym
		a.Node = n.Orig

		//if(a->node >= (Node*)&n)
		//	fatal("stack node");
		if s == nil {
			s = Lookup(".noname")
		}
		if n.Method {
			if n.Type != nil {
				if n.Type.Sym != nil {
					if n.Type.Sym.Pkg != nil {
						s = Pkglookup(s.Name, n.Type.Sym.Pkg)
					}
				}
			}
		}

		a.Type = obj.TYPE_MEM
		switch n.Class {
		default:
			Fatal("naddr: ONAME class %v %d\n", n.Sym, n.Class)

//.........这里部分代码省略.........