Golang Link.Cursym方法代码示例

func follow(ctxt *liblink.Link, s *liblink.LSym) {
	var firstp *liblink.Prog
	var lastp *liblink.Prog
	ctxt.Cursym = s
	firstp = ctxt.Prg()
	lastp = firstp
	xfol(ctxt, s.Text, &lastp)
	lastp.Link = nil
	s.Text = firstp.Link
}

func addstacksplit(ctxt *liblink.Link, cursym *liblink.LSym) {
	var p *liblink.Prog
	var q *liblink.Prog
	var autoffset int64
	var deltasp int64
	var a int
	if ctxt.Symmorestack[0] == nil {
		ctxt.Symmorestack[0] = liblink.Linklookup(ctxt, "runtime.morestack", 0)
		ctxt.Symmorestack[1] = liblink.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
	}
	if ctxt.Headtype == liblink.Hplan9 && ctxt.Plan9privates == nil {
		ctxt.Plan9privates = liblink.Linklookup(ctxt, "_privates", 0)
	}
	ctxt.Cursym = cursym
	if cursym.Text == nil || cursym.Text.Link == nil {
		return
	}
	p = cursym.Text
	autoffset = p.To.Offset
	if autoffset < 0 {
		autoffset = 0
	}
	cursym.Locals = autoffset
	cursym.Args = p.To.Offset2
	q = nil
	if p.From.Scale&liblink.NOSPLIT == 0 || (p.From.Scale&liblink.WRAPPER != 0) {
		p = liblink.Appendp(ctxt, p)
		p = load_g_cx(ctxt, p) // load g into CX
	}
	if cursym.Text.From.Scale&liblink.NOSPLIT == 0 {
		p = stacksplit(ctxt, p, autoffset, bool2int(cursym.Text.From.Scale&liblink.NEEDCTXT == 0), &q) // emit split check
	}
	if autoffset != 0 {
		p = liblink.Appendp(ctxt, p)
		p.As = AADJSP
		p.From.Typ = D_CONST
		p.From.Offset = autoffset
		p.Spadj = autoffset
	} else {
		// zero-byte stack adjustment.
		// Insert a fake non-zero adjustment so that stkcheck can
		// recognize the end of the stack-splitting prolog.
		p = liblink.Appendp(ctxt, p)
		p.As = ANOP
		p.Spadj = -ctxt.Arch.Ptrsize
		p = liblink.Appendp(ctxt, p)
		p.As = ANOP
		p.Spadj = ctxt.Arch.Ptrsize
	}
	if q != nil {
		q.Pcond = p
	}
	deltasp = autoffset
	if cursym.Text.From.Scale&liblink.WRAPPER != 0 {
		// g->panicwrap += autoffset + ctxt->arch->ptrsize;
		p = liblink.Appendp(ctxt, p)
		p.As = AADDL
		p.From.Typ = D_CONST
		p.From.Offset = autoffset + ctxt.Arch.Ptrsize
		p.To.Typ = D_INDIR + D_CX
		p.To.Offset = 2 * ctxt.Arch.Ptrsize
	}
	if ctxt.Debugzerostack != 0 && autoffset != 0 && cursym.Text.From.Scale&liblink.NOSPLIT == 0 {
		// 8l -Z means zero the stack frame on entry.
		// This slows down function calls but can help avoid
		// false positives in garbage collection.
		p = liblink.Appendp(ctxt, p)
		p.As = AMOVL
		p.From.Typ = D_SP
		p.To.Typ = D_DI
		p = liblink.Appendp(ctxt, p)
		p.As = AMOVL
		p.From.Typ = D_CONST
		p.From.Offset = autoffset / 4
		p.To.Typ = D_CX
		p = liblink.Appendp(ctxt, p)
		p.As = AMOVL
		p.From.Typ = D_CONST
		p.From.Offset = 0
		p.To.Typ = D_AX
		p = liblink.Appendp(ctxt, p)
		p.As = AREP
		p = liblink.Appendp(ctxt, p)
		p.As = ASTOSL
	}
	for ; p != nil; p = p.Link {
		a = p.From.Typ
		if a == D_AUTO {
			p.From.Offset += deltasp
		}
		if a == D_PARAM {
			p.From.Offset += deltasp + 4
		}
		a = p.To.Typ
		if a == D_AUTO {
			p.To.Offset += deltasp
		}
		if a == D_PARAM {
			p.To.Offset += deltasp + 4
		}
//.........这里部分代码省略.........

func addstacksplit(ctxt *liblink.Link, cursym *liblink.LSym) {
	var p *liblink.Prog
	var pl *liblink.Prog
	var q *liblink.Prog
	var q1 *liblink.Prog
	var q2 *liblink.Prog
	var o int
	var autosize int64
	var autoffset int64
	autosize = 0
	if ctxt.Symmorestack[0] == nil {
		ctxt.Symmorestack[0] = liblink.Linklookup(ctxt, "runtime.morestack", 0)
		ctxt.Symmorestack[1] = liblink.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
	}
	q = nil
	ctxt.Cursym = cursym
	if cursym.Text == nil || cursym.Text.Link == nil {
		return
	}
	softfloat(ctxt, cursym)
	p = cursym.Text
	autoffset = p.To.Offset
	if autoffset < 0 {
		autoffset = 0
	}
	cursym.Locals = autoffset
	cursym.Args = p.To.Offset2
	if ctxt.Debugzerostack != 0 {
		if autoffset != 0 && p.Reg&liblink.NOSPLIT == 0 {
			// MOVW $4(R13), R1
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.From.Typ = D_CONST
			p.From.Reg = 13
			p.From.Offset = 4
			p.To.Typ = D_REG
			p.To.Reg = 1
			// MOVW $n(R13), R2
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.From.Typ = D_CONST
			p.From.Reg = 13
			p.From.Offset = 4 + autoffset
			p.To.Typ = D_REG
			p.To.Reg = 2
			// MOVW $0, R3
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.From.Typ = D_CONST
			p.From.Offset = 0
			p.To.Typ = D_REG
			p.To.Reg = 3
			// L:
			//	MOVW.nil R3, 0(R1) +4
			//	CMP R1, R2
			//	BNE L
			pl = liblink.Appendp(ctxt, p)
			p = pl
			p.As = AMOVW
			p.From.Typ = D_REG
			p.From.Reg = 3
			p.To.Typ = D_OREG
			p.To.Reg = 1
			p.To.Offset = 4
			p.Scond |= C_PBIT
			p = liblink.Appendp(ctxt, p)
			p.As = ACMP
			p.From.Typ = D_REG
			p.From.Reg = 1
			p.Reg = 2
			p = liblink.Appendp(ctxt, p)
			p.As = ABNE
			p.To.Typ = D_BRANCH
			p.Pcond = pl
		}
	}
	/*
	 * find leaf subroutines
	 * strip NOPs
	 * expand RET
	 * expand BECOME pseudo
	 */
	for p = cursym.Text; p != nil; p = p.Link {
		switch p.As {
		case ACASE:
			if ctxt.Flag_shared != 0 {
				linkcase(p)
			}
		case ATEXT:
			p.Mark |= LEAF
		case ARET:
			break
		case ADIV,
			ADIVU,
			AMOD,
			AMODU:
			q = p
			if ctxt.Sym_div == nil {
				initdiv(ctxt)
			}
//.........这里部分代码省略.........