Golang obj.Linklookup函數代碼示例

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
}

func initdiv(ctxt *obj.Link) {
	if ctxt.Sym_div != nil {
		return
	}
	ctxt.Sym_div = obj.Linklookup(ctxt, "_div", 0)
	ctxt.Sym_divu = obj.Linklookup(ctxt, "_divu", 0)
	ctxt.Sym_mod = obj.Linklookup(ctxt, "_mod", 0)
	ctxt.Sym_modu = obj.Linklookup(ctxt, "_modu", 0)
}

func stacksplitPost(ctxt *obj.Link, p *obj.Prog, pPre *obj.Prog, pPreempt *obj.Prog, framesize int32) *obj.Prog {
	// Now we are at the end of the function, but logically
	// we are still in function prologue. We need to fix the
	// SP data and PCDATA.
	spfix := obj.Appendp(ctxt, p)
	spfix.As = obj.ANOP
	spfix.Spadj = -framesize

	pcdata := obj.Appendp(ctxt, spfix)
	pcdata.Lineno = ctxt.Cursym.Text.Lineno
	pcdata.Mode = ctxt.Cursym.Text.Mode
	pcdata.As = obj.APCDATA
	pcdata.From.Type = obj.TYPE_CONST
	pcdata.From.Offset = obj.PCDATA_StackMapIndex
	pcdata.To.Type = obj.TYPE_CONST
	pcdata.To.Offset = -1 // pcdata starts at -1 at function entry

	// MOVD	LR, R5
	p = obj.Appendp(ctxt, pcdata)
	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
}

func stringsym(s string) (data *obj.LSym) {
	var symname string
	if len(s) > 100 {
		// Huge strings are hashed to avoid long names in object files.
		// Indulge in some paranoia by writing the length of s, too,
		// as protection against length extension attacks.
		h := sha256.New()
		io.WriteString(h, s)
		symname = fmt.Sprintf(".gostring.%d.%x", len(s), h.Sum(nil))
	} else {
		// Small strings get named directly by their contents.
		symname = strconv.Quote(s)
	}

	const prefix = "go.string."
	symdataname := prefix + symname

	symdata := obj.Linklookup(Ctxt, symdataname, 0)

	if !symdata.SeenGlobl() {
		// string data
		off := dsnameLSym(symdata, 0, s)
		ggloblLSym(symdata, int32(off), obj.DUPOK|obj.RODATA|obj.LOCAL)
	}

	return symdata
}

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 dimportpath(p *Pkg) {
	if p.Pathsym != nil {
		return
	}

	// If we are compiling the runtime package, there are two runtime packages around
	// -- localpkg and Runtimepkg. We don't want to produce import path symbols for
	// both of them, so just produce one for localpkg.
	if myimportpath == "runtime" && p == Runtimepkg {
		return
	}

	var str string
	if p == localpkg {
		// Note: myimportpath != "", or else dgopkgpath won't call dimportpath.
		str = myimportpath
	} else {
		str = p.Path
	}

	s := obj.Linklookup(Ctxt, "type..importpath."+p.Prefix+".", 0)
	ot := dnameData(s, 0, str, "", nil, false)
	ggloblLSym(s, int32(ot), obj.DUPOK|obj.RODATA)
	p.Pathsym = s
}

// dname creates a reflect.name for a struct field or method.
func dname(name, tag string, pkg *Pkg, exported bool) *obj.LSym {
	// Write out data as "type.." to signal two things to the
	// linker, first that when dynamically linking, the symbol
	// should be moved to a relro section, and second that the
	// contents should not be decoded as a type.
	sname := "type..namedata."
	if pkg == nil {
		// In the common case, share data with other packages.
		if name == "" {
			if exported {
				sname += "-noname-exported." + tag
			} else {
				sname += "-noname-unexported." + tag
			}
		} else {
			sname += name + "." + tag
		}
	} else {
		sname = fmt.Sprintf(`%s"".%d`, sname, dnameCount)
		dnameCount++
	}
	s := obj.Linklookup(Ctxt, sname, 0)
	if len(s.P) > 0 {
		return s
	}
	ot := dnameData(s, 0, name, tag, pkg, exported)
	ggloblLSym(s, int32(ot), obj.DUPOK|obj.RODATA)
	return s
}

// dname dumps a reflect.name for a struct field or method.
func dname(s *Sym, ot int, name, tag string, pkg *Pkg, exported bool) int {
	if len(name) > 1<<16-1 {
		Fatalf("name too long: %s", name)
	}
	if len(tag) > 1<<16-1 {
		Fatalf("tag too long: %s", tag)
	}

	// Encode name and tag. See reflect/type.go for details.
	var bits byte
	l := 1 + 2 + len(name)
	if exported {
		bits |= 1 << 0
	}
	if len(tag) > 0 {
		l += 2 + len(tag)
		bits |= 1 << 1
	}
	if pkg != nil {
		bits |= 1 << 2
	}
	b := make([]byte, l)
	b[0] = bits
	b[1] = uint8(len(name) >> 8)
	b[2] = uint8(len(name))
	copy(b[3:], name)
	if len(tag) > 0 {
		tb := b[3+len(name):]
		tb[0] = uint8(len(tag) >> 8)
		tb[1] = uint8(len(tag))
		copy(tb[2:], tag)
	}

	// Very few names require a pkgPath *string (only those
	// defined in a different package than their type). So if
	// there is no pkgPath, we treat the name contents as string
	// data that duplicates across packages.
	var bsym *obj.LSym
	if pkg == nil {
		_, bsym = stringsym(string(b))
	} else {
		// Write out data as "type.." to signal two things to the
		// linker, first that when dynamically linking, the symbol
		// should be moved to a relro section, and second that the
		// contents should not be decoded as a type.
		bsymname := fmt.Sprintf(`type..methodname."".%d`, dnameCount)
		dnameCount++
		bsym = obj.Linklookup(Ctxt, bsymname, 0)
		bsym.P = b
		boff := len(b)
		boff = int(Rnd(int64(boff), int64(Widthptr)))
		boff = dgopkgpathLSym(bsym, boff, pkg)
		ggloblLSym(bsym, int32(boff), obj.RODATA|obj.LOCAL)
	}

	ot = dsymptrLSym(Linksym(s), ot, bsym, 0)

	return ot
}

func stringsym(s string) (hdr, data *obj.LSym) {
	var symname string
	if len(s) > 100 {
		// Huge strings are hashed to avoid long names in object files.
		// Indulge in some paranoia by writing the length of s, too,
		// as protection against length extension attacks.
		h := sha256.New()
		io.WriteString(h, s)
		symname = fmt.Sprintf(".gostring.%d.%x", len(s), h.Sum(nil))
	} else {
		// Small strings get named directly by their contents.
		symname = strconv.Quote(s)
	}

	const prefix = "go.string."
	symdataname := prefix + symname

	// All the strings have the same prefix, so ignore it for map
	// purposes, but use a slice of the symbol name string to
	// reduce long-term memory overhead.
	key := symdataname[len(prefix):]

	if syms, ok := stringConstants[key]; ok {
		return syms.hdr, syms.data
	}

	symhdrname := "go.string.hdr." + symname

	symhdr := obj.Linklookup(Ctxt, symhdrname, 0)
	symdata := obj.Linklookup(Ctxt, symdataname, 0)

	stringConstants[key] = stringConstantSyms{symhdr, symdata}

	// string header
	off := 0
	off = dsymptrLSym(symhdr, off, symdata, 0)
	off = duintxxLSym(symhdr, off, uint64(len(s)), Widthint)
	ggloblLSym(symhdr, int32(off), obj.DUPOK|obj.RODATA|obj.LOCAL)

	// string data
	off = dsnameLSym(symdata, 0, s)
	ggloblLSym(symdata, int32(off), obj.DUPOK|obj.RODATA|obj.LOCAL)

	return symhdr, symdata
}

// dgopkgpathOffLSym writes an offset relocation in s at offset ot to the pkg path symbol.
func dgopkgpathOffLSym(s *obj.LSym, ot int, pkg *Pkg) int {
	if pkg == nil {
		return duintxxLSym(s, ot, 0, 4)
	}
	if pkg == localpkg && myimportpath == "" {
		// If we don't know the full import path of the package being compiled
		// (i.e. -p was not passed on the compiler command line), emit a reference to
		// type..importpath.""., which the linker will rewrite using the correct import path.
		// Every package that imports this one directly defines the symbol.
		// See also https://groups.google.com/forum/#!topic/golang-dev/myb9s53HxGQ.
		ns := obj.Linklookup(Ctxt, `type..importpath."".`, 0)
		return dsymptrOffLSym(s, ot, ns, 0)
	}

	dimportpath(pkg)
	return dsymptrOffLSym(s, ot, pkg.Pathsym, 0)
}

func Linksym(s *Sym) *obj.LSym {
	if s == nil {
		return nil
	}
	if s.Lsym != nil {
		return s.Lsym
	}
	var name string
	if isblanksym(s) {
		name = "_"
	} else if s.Linkname != "" {
		name = s.Linkname
	} else {
		name = s.Pkg.Prefix + "." + s.Name
	}

	ls := obj.Linklookup(Ctxt, name, 0)
	s.Lsym = ls
	return ls
}

//.........這裏部分代碼省略.........
		}
	}

	order(Curfn)
	if nerrors != 0 {
		return
	}

	hasdefer = false
	walk(Curfn)
	if nerrors != 0 {
		return
	}
	if instrumenting {
		instrument(Curfn)
	}
	if nerrors != 0 {
		return
	}

	// Build an SSA backend function.
	ssafn := buildssa(Curfn)
	if nerrors != 0 {
		return
	}

	newplist()

	setlineno(Curfn)

	nam := Curfn.Func.Nname
	if isblank(nam) {
		nam = nil
	}
	ptxt := Gins(obj.ATEXT, nam, nil)
	ptxt.From3 = new(obj.Addr)
	if fn.Func.Dupok {
		ptxt.From3.Offset |= obj.DUPOK
	}
	if fn.Func.Wrapper {
		ptxt.From3.Offset |= obj.WRAPPER
	}
	if fn.Func.Needctxt {
		ptxt.From3.Offset |= obj.NEEDCTXT
	}
	if fn.Func.Pragma&Nosplit != 0 {
		ptxt.From3.Offset |= obj.NOSPLIT
	}
	if fn.Func.ReflectMethod {
		ptxt.From3.Offset |= obj.REFLECTMETHOD
	}
	if fn.Func.Pragma&Systemstack != 0 {
		ptxt.From.Sym.Set(obj.AttrCFunc, true)
	}

	// Clumsy but important.
	// See test/recover.go for test cases and src/reflect/value.go
	// for the actual functions being considered.
	if myimportpath == "reflect" {
		if Curfn.Func.Nname.Sym.Name == "callReflect" || Curfn.Func.Nname.Sym.Name == "callMethod" {
			ptxt.From3.Offset |= obj.WRAPPER
		}
	}

	gcargs := makefuncdatasym("gcargs·", obj.FUNCDATA_ArgsPointerMaps)
	gclocals := makefuncdatasym("gclocals·", obj.FUNCDATA_LocalsPointerMaps)

	if obj.Fieldtrack_enabled != 0 && len(Curfn.Func.FieldTrack) > 0 {
		trackSyms := make([]*Sym, 0, len(Curfn.Func.FieldTrack))
		for sym := range Curfn.Func.FieldTrack {
			trackSyms = append(trackSyms, sym)
		}
		sort.Sort(symByName(trackSyms))
		for _, sym := range trackSyms {
			gtrack(sym)
		}
	}

	for _, n := range fn.Func.Dcl {
		if n.Op != ONAME { // might be OTYPE or OLITERAL
			continue
		}
		switch n.Class {
		case PAUTO:
			if !n.Used {
				continue
			}
			fallthrough
		case PPARAM, PPARAMOUT:
			p := Gins(obj.ATYPE, n, nil)
			p.From.Sym = obj.Linklookup(Ctxt, n.Sym.Name, 0)
			p.To.Type = obj.TYPE_MEM
			p.To.Name = obj.NAME_EXTERN
			p.To.Sym = Linksym(ngotype(n))
		}
	}

	genssa(ssafn, ptxt, gcargs, gclocals)
	ssafn.Free()
}

//.........這裏部分代碼省略.........
	case 104:
		yyDollar = yyS[yypt-1 : yypt+1]
		//line a.y:665
		{
			yyVAL.addr = nullgen
			yyVAL.addr.Type = obj.TYPE_REG
			yyVAL.addr.Reg = int16(yyDollar[1].lval)
		}
	case 105:
		yyDollar = yyS[yypt-4 : yypt+1]
		//line a.y:671
		{
			yyVAL.addr = nullgen
			yyVAL.addr.Type = obj.TYPE_REG
			yyVAL.addr.Reg = int16(REG_F0 + yyDollar[3].lval)
		}
	case 106:
		yyDollar = yyS[yypt-4 : yypt+1]
		//line a.y:679
		{
			yyVAL.addr = nullgen
			yyVAL.addr.Type = obj.TYPE_MEM
			yyVAL.addr.Name = int8(yyDollar[3].lval)
			yyVAL.addr.Sym = nil
			yyVAL.addr.Offset = int64(yyDollar[1].lval)
		}
	case 107:
		yyDollar = yyS[yypt-5 : yypt+1]
		//line a.y:687
		{
			yyVAL.addr = nullgen
			yyVAL.addr.Type = obj.TYPE_MEM
			yyVAL.addr.Name = int8(yyDollar[4].lval)
			yyVAL.addr.Sym = obj.Linklookup(asm.Ctxt, yyDollar[1].sym.Name, 0)
			yyVAL.addr.Offset = int64(yyDollar[2].lval)
		}
	case 108:
		yyDollar = yyS[yypt-7 : yypt+1]
		//line a.y:695
		{
			yyVAL.addr = nullgen
			yyVAL.addr.Type = obj.TYPE_MEM
			yyVAL.addr.Name = obj.NAME_STATIC
			yyVAL.addr.Sym = obj.Linklookup(asm.Ctxt, yyDollar[1].sym.Name, 1)
			yyVAL.addr.Offset = int64(yyDollar[4].lval)
		}
	case 109:
		yyDollar = yyS[yypt-0 : yypt+1]
		//line a.y:704
		{
			yyVAL.lval = 0
		}
	case 110:
		yyDollar = yyS[yypt-2 : yypt+1]
		//line a.y:708
		{
			yyVAL.lval = yyDollar[2].lval
		}
	case 111:
		yyDollar = yyS[yypt-2 : yypt+1]
		//line a.y:712
		{
			yyVAL.lval = -yyDollar[2].lval
		}
	case 116:
		yyDollar = yyS[yypt-1 : yypt+1]

func dumptypestructs() {
	// copy types from externdcl list to signatlist
	for _, n := range externdcl {
		if n.Op != OTYPE {
			continue
		}
		signatlist = append(signatlist, n)
	}

	// Process signatlist.  This can't use range, as entries are
	// added to the list while it is being processed.
	for i := 0; i < len(signatlist); i++ {
		n := signatlist[i]
		if n.Op != OTYPE {
			continue
		}
		t := n.Type
		dtypesym(t)
		if t.Sym != nil {
			dtypesym(ptrto(t))
		}
	}

	// process itabs
	for _, i := range itabs {
		// dump empty itab symbol into i.sym
		// type itab struct {
		//   inter  *interfacetype
		//   _type  *_type
		//   link   *itab
		//   bad    int32
		//   unused int32
		//   fun    [1]uintptr // variable sized
		// }
		o := dsymptr(i.sym, 0, dtypesym(i.itype), 0)
		o = dsymptr(i.sym, o, dtypesym(i.t), 0)
		o += Widthptr + 8                      // skip link/bad/unused fields
		o += len(imethods(i.itype)) * Widthptr // skip fun method pointers
		// at runtime the itab will contain pointers to types, other itabs and
		// method functions. None are allocated on heap, so we can use obj.NOPTR.
		ggloblsym(i.sym, int32(o), int16(obj.DUPOK|obj.NOPTR|obj.LOCAL))

		ilink := Pkglookup(i.t.tconv(FmtLeft)+","+i.itype.tconv(FmtLeft), itablinkpkg)
		dsymptr(ilink, 0, i.sym, 0)
		ggloblsym(ilink, int32(Widthptr), int16(obj.DUPOK|obj.RODATA|obj.LOCAL))
	}

	// process ptabs
	if localpkg.Name == "main" && len(ptabs) > 0 {
		ot := 0
		s := obj.Linklookup(Ctxt, "go.plugin.tabs", 0)
		for _, p := range ptabs {
			// Dump ptab symbol into go.pluginsym package.
			//
			// type ptab struct {
			//	name nameOff
			//	typ  typeOff // pointer to symbol
			// }
			nsym := dname(p.s.Name, "", nil, true)
			ot = dsymptrOffLSym(s, ot, nsym, 0)
			ot = dsymptrOffLSym(s, ot, Linksym(dtypesym(p.t)), 0)
		}
		ggloblLSym(s, int32(ot), int16(obj.RODATA))

		ot = 0
		s = obj.Linklookup(Ctxt, "go.plugin.exports", 0)
		for _, p := range ptabs {
			ot = dsymptrLSym(s, ot, Linksym(p.s), 0)
		}
		ggloblLSym(s, int32(ot), int16(obj.RODATA))
	}

	// generate import strings for imported packages
	if forceObjFileStability {
		// Sorting the packages is not necessary but to compare binaries created
		// using textual and binary format we sort by path to reduce differences.
		sort.Sort(pkgByPath(pkgs))
	}
	for _, p := range pkgs {
		if p.Direct {
			dimportpath(p)
		}
	}

	// do basic types if compiling package runtime.
	// they have to be in at least one package,
	// and runtime is always loaded implicitly,
	// so this is as good as any.
	// another possible choice would be package main,
	// but using runtime means fewer copies in .6 files.
	if myimportpath == "runtime" {
		for i := EType(1); i <= TBOOL; i++ {
			dtypesym(ptrto(Types[i]))
		}
		dtypesym(ptrto(Types[TSTRING]))
		dtypesym(ptrto(Types[TUNSAFEPTR]))

		// emit type structs for error and func(error) string.
		// The latter is the type of an auto-generated wrapper.
		dtypesym(ptrto(errortype))
//.........這裏部分代碼省略.........

func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
	if ctxt.Headtype == obj.Hplan9 && ctxt.Plan9privates == nil {
		ctxt.Plan9privates = obj.Linklookup(ctxt, "_privates", 0)
	}

	ctxt.Cursym = cursym

	if cursym.Text == nil || cursym.Text.Link == nil {
		return
	}

	p := cursym.Text
	autoffset := int32(p.To.Offset)
	if autoffset < 0 {
		autoffset = 0
	}

	var bpsize int
	if p.Mode == 64 && obj.Framepointer_enabled != 0 && autoffset > 0 {
		// Make room for to save a base pointer. If autoffset == 0,
		// this might do something special like a tail jump to
		// another function, so in that case we omit this.
		bpsize = ctxt.Arch.Ptrsize

		autoffset += int32(bpsize)
		p.To.Offset += int64(bpsize)
	} else {
		bpsize = 0
	}

	textarg := int64(p.To.Val.(int32))
	cursym.Args = int32(textarg)
	cursym.Locals = int32(p.To.Offset)

	// TODO(rsc): Remove.
	if p.Mode == 32 && cursym.Locals < 0 {
		cursym.Locals = 0
	}

	// TODO(rsc): Remove 'p.Mode == 64 &&'.
	if p.Mode == 64 && autoffset < obj.StackSmall && p.From3Offset()&obj.NOSPLIT == 0 {
		for q := p; q != nil; q = q.Link {
			if q.As == obj.ACALL {
				goto noleaf
			}
			if (q.As == obj.ADUFFCOPY || q.As == obj.ADUFFZERO) && autoffset >= obj.StackSmall-8 {
				goto noleaf
			}
		}

		p.From3.Offset |= obj.NOSPLIT
	noleaf:
	}

	if p.From3Offset()&obj.NOSPLIT == 0 || p.From3Offset()&obj.WRAPPER != 0 {
		p = obj.Appendp(ctxt, p)
		p = load_g_cx(ctxt, p) // load g into CX
	}

	if cursym.Text.From3Offset()&obj.NOSPLIT == 0 {
		p = stacksplit(ctxt, p, autoffset, int32(textarg)) // emit split check
	}

	if autoffset != 0 {
		if autoffset%int32(ctxt.Arch.Regsize) != 0 {
			ctxt.Diag("unaligned stack size %d", autoffset)
		}
		p = obj.Appendp(ctxt, p)
		p.As = AADJSP
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = int64(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 = obj.Appendp(ctxt, p)

		p.As = obj.ANOP
		p.Spadj = int32(-ctxt.Arch.Ptrsize)
		p = obj.Appendp(ctxt, p)
		p.As = obj.ANOP
		p.Spadj = int32(ctxt.Arch.Ptrsize)
	}

	deltasp := autoffset

	if bpsize > 0 {
		// Save caller's BP
		p = obj.Appendp(ctxt, p)

		p.As = AMOVQ
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_BP
		p.To.Type = obj.TYPE_MEM
		p.To.Reg = REG_SP
		p.To.Scale = 1
		p.To.Offset = int64(autoffset) - int64(bpsize)

		// Move current frame to BP
//.........這裏部分代碼省略.........