Golang obj.Cputime函數代碼示例

func reloc() {
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f reloc\n", obj.Cputime())
	}
	Bflush(&Bso)

	for s := Ctxt.Textp; s != nil; s = s.Next {
		relocsym(s)
	}
	for s := datap; s != nil; s = s.Next {
		relocsym(s)
	}
}

func dynreloc() {
	// -d suppresses dynamic loader format, so we may as well not
	// compute these sections or mark their symbols as reachable.
	if Debug['d'] != 0 && HEADTYPE != Hwindows {
		return
	}
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f reloc\n", obj.Cputime())
	}
	Bflush(&Bso)

	for s := Ctxt.Textp; s != nil; s = s.Next {
		dynrelocsym(s)
	}
	for s := datap; s != nil; s = s.Next {
		dynrelocsym(s)
	}
	if Iself {
		elfdynhash()
	}
}

//.........這裏部分代碼省略.........
	if Buildmode != BuildmodeShared && flag.NArg() != 1 {
		usage()
	}

	if outfile == "" {
		outfile = "a.out"
		if HEADTYPE == obj.Hwindows {
			outfile += ".exe"
		}
	}

	libinit() // creates outfile

	if HEADTYPE == -1 {
		HEADTYPE = int32(headtype(goos))
	}
	Ctxt.Headtype = int(HEADTYPE)
	if headstring == "" {
		headstring = Headstr(int(HEADTYPE))
	}
	if HEADTYPE == obj.Hhaiku {
		Linkmode = LinkExternal
	}

	Thearch.Archinit()

	if Linkshared && !Iself {
		Exitf("-linkshared can only be used on elf systems")
	}

	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "HEADER = -H%d -T0x%x -D0x%x -R0x%x\n", HEADTYPE, uint64(INITTEXT), uint64(INITDAT), uint32(INITRND))
	}
	Bso.Flush()

	if Buildmode == BuildmodeShared {
		for i := 0; i < flag.NArg(); i++ {
			arg := flag.Arg(i)
			parts := strings.SplitN(arg, "=", 2)
			var pkgpath, file string
			if len(parts) == 1 {
				pkgpath, file = "main", arg
			} else {
				pkgpath, file = parts[0], parts[1]
			}
			pkglistfornote = append(pkglistfornote, pkgpath...)
			pkglistfornote = append(pkglistfornote, '\n')
			addlibpath(Ctxt, "command line", "command line", file, pkgpath, "")
		}
	} else {
		addlibpath(Ctxt, "command line", "command line", flag.Arg(0), "main", "")
	}
	loadlib()

	if Thearch.Thechar == '5' {
		// mark some functions that are only referenced after linker code editing
		if Ctxt.Goarm == 5 {
			mark(Linkrlookup(Ctxt, "_sfloat", 0))
		}
		mark(Linklookup(Ctxt, "runtime.read_tls_fallback", 0))
	}

	checkgo()
	checkstrdata()
	deadcode()
	callgraph()

	doelf()
	if HEADTYPE == obj.Hdarwin {
		domacho()
	}
	dostkcheck()
	if HEADTYPE == obj.Hwindows {
		dope()
	}
	addexport()
	Thearch.Gentext() // trampolines, call stubs, etc.
	textbuildid()
	textaddress()
	pclntab()
	findfunctab()
	symtab()
	dodata()
	address()
	doweak()
	reloc()
	Thearch.Asmb()
	undef()
	hostlink()
	archive()
	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f cpu time\n", obj.Cputime())
		fmt.Fprintf(&Bso, "%d symbols\n", Ctxt.Nsymbol)
		fmt.Fprintf(&Bso, "%d liveness data\n", liveness)
	}

	Bso.Flush()

	errorexit()
}

func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
	// TODO(minux): add morestack short-cuts with small fixed frame-size.
	ctxt.Cursym = cursym

	// a switch for enabling/disabling instruction scheduling
	nosched := true

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

	p := cursym.Text
	textstksiz := p.To.Offset

	cursym.Args = p.To.Val.(int32)
	cursym.Locals = int32(textstksiz)

	/*
	 * find leaf subroutines
	 * strip NOPs
	 * expand RET
	 * expand BECOME pseudo
	 */
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f noops\n", obj.Cputime())
	}

	var q *obj.Prog
	var q1 *obj.Prog
	for p := cursym.Text; p != nil; p = p.Link {
		switch p.As {
		/* too hard, just leave alone */
		case obj.ATEXT:
			q = p

			p.Mark |= LABEL | LEAF | SYNC
			if p.Link != nil {
				p.Link.Mark |= LABEL
			}

		/* too hard, just leave alone */
		case AMOVW,
			AMOVV:
			q = p
			if p.To.Type == obj.TYPE_REG && p.To.Reg >= REG_SPECIAL {
				p.Mark |= LABEL | SYNC
				break
			}
			if p.From.Type == obj.TYPE_REG && p.From.Reg >= REG_SPECIAL {
				p.Mark |= LABEL | SYNC
			}

		/* too hard, just leave alone */
		case ASYSCALL,
			AWORD,
			ATLBWR,
			ATLBWI,
			ATLBP,
			ATLBR:
			q = p
			p.Mark |= LABEL | SYNC

		case ANOR:
			q = p
			if p.To.Type == obj.TYPE_REG {
				if p.To.Reg == REGZERO {
					p.Mark |= LABEL | SYNC
				}
			}

		case ABGEZAL,
			ABLTZAL,
			AJAL,
			obj.ADUFFZERO,
			obj.ADUFFCOPY:
			cursym.Text.Mark &^= LEAF
			fallthrough

		case AJMP,
			ABEQ,
			ABGEZ,
			ABGTZ,
			ABLEZ,
			ABLTZ,
			ABNE,
			ABFPT, ABFPF:
			if p.As == ABFPT || p.As == ABFPF {
				// We don't treat ABFPT and ABFPF as branches here,
				// so that we will always fill nop (0x0) in their
				// delay slot during assembly.
				// This is to workaround a kernel FPU emulator bug
				// where it uses the user stack to simulate the
				// instruction in the delay slot if it's not 0x0,
				// and somehow that leads to SIGSEGV when the kernel
				// jump to the stack.
				p.Mark |= SYNC
			} else {
				p.Mark |= BRANCH
			}
			q = p
//.........這裏部分代碼省略.........

func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f ldelf %s\n", obj.Cputime(), pn)
	}

	localSymVersion := ctxt.Syms.IncVersion()
	base := f.Offset()

	var add uint64
	var e binary.ByteOrder
	var elfobj *ElfObj
	var err error
	var flag int
	var hdr *ElfHdrBytes
	var hdrbuf [64]uint8
	var info uint64
	var is64 int
	var j int
	var n int
	var name string
	var p []byte
	var r []Reloc
	var rela int
	var rp *Reloc
	var rsect *ElfSect
	var s *Symbol
	var sect *ElfSect
	var sym ElfSym
	var symbols []*Symbol
	if _, err := io.ReadFull(f, hdrbuf[:]); err != nil {
		goto bad
	}
	hdr = new(ElfHdrBytes)
	binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter
	if string(hdr.Ident[:4]) != "\x7FELF" {
		goto bad
	}
	switch hdr.Ident[5] {
	case ElfDataLsb:
		e = binary.LittleEndian

	case ElfDataMsb:
		e = binary.BigEndian

	default:
		goto bad
	}

	// read header
	elfobj = new(ElfObj)

	elfobj.e = e
	elfobj.f = f
	elfobj.base = base
	elfobj.length = length
	elfobj.name = pn

	is64 = 0
	if hdr.Ident[4] == ElfClass64 {
		is64 = 1
		hdr := new(ElfHdrBytes64)
		binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter
		elfobj.type_ = uint32(e.Uint16(hdr.Type[:]))
		elfobj.machine = uint32(e.Uint16(hdr.Machine[:]))
		elfobj.version = e.Uint32(hdr.Version[:])
		elfobj.phoff = e.Uint64(hdr.Phoff[:])
		elfobj.shoff = e.Uint64(hdr.Shoff[:])
		elfobj.flags = e.Uint32(hdr.Flags[:])
		elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:]))
		elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:]))
		elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:]))
		elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:]))
		elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:]))
		elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:]))
	} else {
		elfobj.type_ = uint32(e.Uint16(hdr.Type[:]))
		elfobj.machine = uint32(e.Uint16(hdr.Machine[:]))
		elfobj.version = e.Uint32(hdr.Version[:])
		elfobj.entry = uint64(e.Uint32(hdr.Entry[:]))
		elfobj.phoff = uint64(e.Uint32(hdr.Phoff[:]))
		elfobj.shoff = uint64(e.Uint32(hdr.Shoff[:]))
		elfobj.flags = e.Uint32(hdr.Flags[:])
		elfobj.ehsize = uint32(e.Uint16(hdr.Ehsize[:]))
		elfobj.phentsize = uint32(e.Uint16(hdr.Phentsize[:]))
		elfobj.phnum = uint32(e.Uint16(hdr.Phnum[:]))
		elfobj.shentsize = uint32(e.Uint16(hdr.Shentsize[:]))
		elfobj.shnum = uint32(e.Uint16(hdr.Shnum[:]))
		elfobj.shstrndx = uint32(e.Uint16(hdr.Shstrndx[:]))
	}

	elfobj.is64 = is64

	if uint32(hdr.Ident[6]) != elfobj.version {
		goto bad
	}

	if e.Uint16(hdr.Type[:]) != ElfTypeRelocatable {
		Errorf(nil, "%s: elf but not elf relocatable object", pn)
		return
	}
//.........這裏部分代碼省略.........

//.........這裏部分代碼省略.........
	if flagShared {
		if Buildmode == BuildmodeUnset {
			Buildmode = BuildmodeCShared
		} else if Buildmode != BuildmodeCShared {
			Exitf("-shared and -buildmode=%s are incompatible", Buildmode.String())
		}
	}
	if Buildmode == BuildmodeUnset {
		Buildmode = BuildmodeExe
	}

	if Buildmode != BuildmodeShared && flag.NArg() != 1 {
		usage()
	}

	if *flagOutfile == "" {
		*flagOutfile = "a.out"
		if HEADTYPE == obj.Hwindows {
			*flagOutfile += ".exe"
		}
	}

	interpreter = *flagInterpreter

	libinit(ctxt) // creates outfile

	if HEADTYPE == -1 {
		HEADTYPE = int32(headtype(goos))
	}
	ctxt.Headtype = int(HEADTYPE)
	if headstring == "" {
		headstring = Headstr(int(HEADTYPE))
	}

	Thearch.Archinit(ctxt)

	if *FlagLinkshared && !Iself {
		Exitf("-linkshared can only be used on elf systems")
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("HEADER = -H%d -T0x%x -D0x%x -R0x%x\n", HEADTYPE, uint64(*FlagTextAddr), uint64(*FlagDataAddr), uint32(*FlagRound))
	}

	if Buildmode == BuildmodeShared {
		for i := 0; i < flag.NArg(); i++ {
			arg := flag.Arg(i)
			parts := strings.SplitN(arg, "=", 2)
			var pkgpath, file string
			if len(parts) == 1 {
				pkgpath, file = "main", arg
			} else {
				pkgpath, file = parts[0], parts[1]
			}
			pkglistfornote = append(pkglistfornote, pkgpath...)
			pkglistfornote = append(pkglistfornote, '\n')
			addlibpath(ctxt, "command line", "command line", file, pkgpath, "")
		}
	} else {
		addlibpath(ctxt, "command line", "command line", flag.Arg(0), "main", "")
	}
	ctxt.loadlib()

	ctxt.checkstrdata()
	deadcode(ctxt)
	fieldtrack(ctxt)
	ctxt.callgraph()

	ctxt.doelf()
	if HEADTYPE == obj.Hdarwin {
		ctxt.domacho()
	}
	ctxt.dostkcheck()
	if HEADTYPE == obj.Hwindows {
		ctxt.dope()
	}
	ctxt.addexport()
	Thearch.Gentext(ctxt) // trampolines, call stubs, etc.
	ctxt.textbuildid()
	ctxt.textaddress()
	ctxt.pclntab()
	ctxt.findfunctab()
	ctxt.symtab()
	ctxt.dodata()
	ctxt.address()
	ctxt.reloc()
	Thearch.Asmb(ctxt)
	ctxt.undef()
	ctxt.hostlink()
	ctxt.archive()
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f cpu time\n", obj.Cputime())
		ctxt.Logf("%d symbols\n", len(ctxt.Allsym))
		ctxt.Logf("%d liveness data\n", liveness)
	}

	ctxt.Bso.Flush()

	errorexit()
}

func span0(ctxt *obj.Link, cursym *obj.LSym) {
	p := cursym.Text
	if p == nil || p.Link == nil { // handle external functions and ELF section symbols
		return
	}
	ctxt.Cursym = cursym
	ctxt.Autosize = int32(p.To.Offset + 8)

	if oprange[AOR&obj.AMask].start == nil {
		buildop(ctxt)
	}

	c := int64(0)
	p.Pc = c

	var m int
	var o *Optab
	for p = p.Link; p != nil; p = p.Link {
		ctxt.Curp = p
		p.Pc = c
		o = oplook(ctxt, p)
		m = int(o.size)
		if m == 0 {
			if p.As != obj.ANOP && p.As != obj.AFUNCDATA && p.As != obj.APCDATA && p.As != obj.AUSEFIELD {
				ctxt.Diag("zero-width instruction\n%v", p)
			}
			continue
		}

		c += int64(m)
	}

	cursym.Size = c

	/*
	 * if any procedure is large enough to
	 * generate a large SBRA branch, then
	 * generate extra passes putting branches
	 * around jmps to fix. this is rare.
	 */
	bflag := 1

	var otxt int64
	var q *obj.Prog
	for bflag != 0 {
		if ctxt.Debugvlog != 0 {
			fmt.Fprintf(ctxt.Bso, "%5.2f span1\n", obj.Cputime())
		}
		bflag = 0
		c = 0
		for p = cursym.Text.Link; p != nil; p = p.Link {
			p.Pc = c
			o = oplook(ctxt, p)

			// very large conditional branches
			if o.type_ == 6 && p.Pcond != nil {
				otxt = p.Pcond.Pc - c
				if otxt < -(1<<17)+10 || otxt >= (1<<17)-10 {
					q = ctxt.NewProg()
					q.Link = p.Link
					p.Link = q
					q.As = AJMP
					q.Lineno = p.Lineno
					q.To.Type = obj.TYPE_BRANCH
					q.Pcond = p.Pcond
					p.Pcond = q
					q = ctxt.NewProg()
					q.Link = p.Link
					p.Link = q
					q.As = AJMP
					q.Lineno = p.Lineno
					q.To.Type = obj.TYPE_BRANCH
					q.Pcond = q.Link.Link

					addnop(ctxt, p.Link)
					addnop(ctxt, p)
					bflag = 1
				}
			}

			m = int(o.size)
			if m == 0 {
				if p.As != obj.ANOP && p.As != obj.AFUNCDATA && p.As != obj.APCDATA && p.As != obj.AUSEFIELD {
					ctxt.Diag("zero-width instruction\n%v", p)
				}
				continue
			}

			c += int64(m)
		}

		cursym.Size = c
	}

	c += -c & (FuncAlign - 1)
	cursym.Size = c

	/*
	 * lay out the code, emitting code and data relocations.
	 */
//.........這裏部分代碼省略.........

//.........這裏部分代碼省略.........
	obj.Flagcount("v", "print link trace", &ctxt.Debugvlog)

	obj.Flagparse(usage)

	startProfile()
	if Buildmode == BuildmodeUnset {
		Buildmode = BuildmodeExe
	}

	if Buildmode != BuildmodeShared && flag.NArg() != 1 {
		usage()
	}

	if *flagOutfile == "" {
		*flagOutfile = "a.out"
		if Headtype == obj.Hwindows || Headtype == obj.Hwindowsgui {
			*flagOutfile += ".exe"
		}
	}

	interpreter = *flagInterpreter

	libinit(ctxt) // creates outfile

	if Headtype == obj.Hunknown {
		Headtype.Set(obj.GOOS)
	}

	ctxt.computeTLSOffset()
	Thearch.Archinit(ctxt)

	if *FlagLinkshared && !Iself {
		Exitf("-linkshared can only be used on elf systems")
	}

	if ctxt.Debugvlog != 0 {
		ctxt.Logf("HEADER = -H%d -T0x%x -D0x%x -R0x%x\n", Headtype, uint64(*FlagTextAddr), uint64(*FlagDataAddr), uint32(*FlagRound))
	}

	switch Buildmode {
	case BuildmodeShared:
		for i := 0; i < flag.NArg(); i++ {
			arg := flag.Arg(i)
			parts := strings.SplitN(arg, "=", 2)
			var pkgpath, file string
			if len(parts) == 1 {
				pkgpath, file = "main", arg
			} else {
				pkgpath, file = parts[0], parts[1]
			}
			pkglistfornote = append(pkglistfornote, pkgpath...)
			pkglistfornote = append(pkglistfornote, '\n')
			addlibpath(ctxt, "command line", "command line", file, pkgpath, "")
		}
	case BuildmodePlugin:
		pluginName := strings.TrimSuffix(filepath.Base(flag.Arg(0)), ".a")
		addlibpath(ctxt, "command line", "command line", flag.Arg(0), pluginName, "")
	default:
		addlibpath(ctxt, "command line", "command line", flag.Arg(0), "main", "")
	}
	ctxt.loadlib()

	ctxt.checkstrdata()
	deadcode(ctxt)
	fieldtrack(ctxt)
	ctxt.callgraph()

	ctxt.doelf()
	if Headtype == obj.Hdarwin {
		ctxt.domacho()
	}
	ctxt.dostkcheck()
	if Headtype == obj.Hwindows || Headtype == obj.Hwindowsgui {
		ctxt.dope()
	}
	ctxt.addexport()
	Thearch.Gentext(ctxt) // trampolines, call stubs, etc.
	ctxt.textbuildid()
	ctxt.textaddress()
	ctxt.pclntab()
	ctxt.findfunctab()
	ctxt.typelink()
	ctxt.symtab()
	ctxt.dodata()
	ctxt.address()
	ctxt.reloc()
	Thearch.Asmb(ctxt)
	ctxt.undef()
	ctxt.hostlink()
	ctxt.archive()
	if ctxt.Debugvlog != 0 {
		ctxt.Logf("%5.2f cpu time\n", obj.Cputime())
		ctxt.Logf("%d symbols\n", len(ctxt.Syms.Allsym))
		ctxt.Logf("%d liveness data\n", liveness)
	}

	ctxt.Bso.Flush()

	errorexit()
}

func ldshlibsyms(shlib string) {
	libpath := findshlib(shlib)
	if libpath == "" {
		return
	}
	for _, processedlib := range Ctxt.Shlibs {
		if processedlib.Path == libpath {
			return
		}
	}
	if Ctxt.Debugvlog > 1 && Ctxt.Bso != nil {
		fmt.Fprintf(Ctxt.Bso, "%5.2f ldshlibsyms: found library with name %s at %s\n", obj.Cputime(), shlib, libpath)
		Ctxt.Bso.Flush()
	}

	f, err := elf.Open(libpath)
	if err != nil {
		Diag("cannot open shared library: %s", libpath)
		return
	}

	hash, err := readnote(f, ELF_NOTE_GO_NAME, ELF_NOTE_GOABIHASH_TAG)
	if err != nil {
		Diag("cannot read ABI hash from shared library %s: %v", libpath, err)
		return
	}

	depsbytes, err := readnote(f, ELF_NOTE_GO_NAME, ELF_NOTE_GODEPS_TAG)
	if err != nil {
		Diag("cannot read dep list from shared library %s: %v", libpath, err)
		return
	}
	deps := strings.Split(string(depsbytes), "\n")

	syms, err := f.DynamicSymbols()
	if err != nil {
		Diag("cannot read symbols from shared library: %s", libpath)
		return
	}
	for _, elfsym := range syms {
		if elf.ST_TYPE(elfsym.Info) == elf.STT_NOTYPE || elf.ST_TYPE(elfsym.Info) == elf.STT_SECTION {
			continue
		}
		lsym := Linklookup(Ctxt, elfsym.Name, 0)
		if lsym.Type != 0 && lsym.Type != obj.SDYNIMPORT && lsym.Dupok == 0 {
			if (lsym.Type != obj.SBSS && lsym.Type != obj.SNOPTRBSS) || len(lsym.R) != 0 || len(lsym.P) != 0 || f.Sections[elfsym.Section].Type != elf.SHT_NOBITS {
				Diag("Found duplicate symbol %s reading from %s, first found in %s", elfsym.Name, shlib, lsym.File)
			}
			if lsym.Size > int64(elfsym.Size) {
				// If the existing symbol is a BSS value that is
				// larger than the one read from the shared library,
				// keep references to that.  Conversely, if the
				// version from the shared libray is larger, we want
				// to make all references be to that.
				continue
			}
		}
		lsym.Type = obj.SDYNIMPORT
		lsym.ElfType = elf.ST_TYPE(elfsym.Info)
		lsym.Size = int64(elfsym.Size)
		if elfsym.Section != elf.SHN_UNDEF {
			// Set .File for the library that actually defines the symbol.
			lsym.File = libpath
			// The decodetype_* functions in decodetype.go need access to
			// the type data.
			if strings.HasPrefix(lsym.Name, "type.") && !strings.HasPrefix(lsym.Name, "type..") {
				lsym.P = readelfsymboldata(f, &elfsym)
			}
		}
	}

	// We might have overwritten some functions above (this tends to happen for the
	// autogenerated type equality/hashing functions) and we don't want to generated
	// pcln table entries for these any more so unstitch them from the Textp linked
	// list.
	var last *LSym

	for s := Ctxt.Textp; s != nil; s = s.Next {
		if s.Type == obj.SDYNIMPORT {
			continue
		}

		if last == nil {
			Ctxt.Textp = s
		} else {
			last.Next = s
		}
		last = s
	}

	if last == nil {
		Ctxt.Textp = nil
		Ctxt.Etextp = nil
	} else {
		last.Next = nil
		Ctxt.Etextp = last
	}

	Ctxt.Shlibs = append(Ctxt.Shlibs, Shlib{Path: libpath, Hash: hash, Deps: deps, File: f})
}

func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
	// TODO(minux): add morestack short-cuts with small fixed frame-size.
	ctxt.Cursym = cursym

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

	p := cursym.Text
	textstksiz := p.To.Offset
	if textstksiz == -8 {
		// Compatibility hack.
		p.From3.Offset |= obj.NOFRAME
		textstksiz = 0
	}
	if textstksiz%8 != 0 {
		ctxt.Diag("frame size %d not a multiple of 8", textstksiz)
	}
	if p.From3.Offset&obj.NOFRAME != 0 {
		if textstksiz != 0 {
			ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz)
		}
	}

	cursym.Args = p.To.Val.(int32)
	cursym.Locals = int32(textstksiz)

	/*
	 * find leaf subroutines
	 * strip NOPs
	 * expand RET
	 * expand BECOME pseudo
	 */
	if ctxt.Debugvlog != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f noops\n", obj.Cputime())
	}
	ctxt.Bso.Flush()

	var q *obj.Prog
	var q1 *obj.Prog
	for p := cursym.Text; p != nil; p = p.Link {
		switch p.As {
		/* too hard, just leave alone */
		case obj.ATEXT:
			q = p

			p.Mark |= LABEL | LEAF | SYNC
			if p.Link != nil {
				p.Link.Mark |= LABEL
			}

		case ANOR:
			q = p
			if p.To.Type == obj.TYPE_REG {
				if p.To.Reg == REGZERO {
					p.Mark |= LABEL | SYNC
				}
			}

		case ALWAR,
			ASTWCCC,
			AECIWX,
			AECOWX,
			AEIEIO,
			AICBI,
			AISYNC,
			ATLBIE,
			ATLBIEL,
			ASLBIA,
			ASLBIE,
			ASLBMFEE,
			ASLBMFEV,
			ASLBMTE,
			ADCBF,
			ADCBI,
			ADCBST,
			ADCBT,
			ADCBTST,
			ADCBZ,
			ASYNC,
			ATLBSYNC,
			APTESYNC,
			ATW,
			AWORD,
			ARFI,
			ARFCI,
			ARFID,
			AHRFID:
			q = p
			p.Mark |= LABEL | SYNC
			continue

		case AMOVW, AMOVWZ, AMOVD:
			q = p
			if p.From.Reg >= REG_SPECIAL || p.To.Reg >= REG_SPECIAL {
				p.Mark |= LABEL | SYNC
			}
			continue

		case AFABS,
//.........這裏部分代碼省略.........

func asmb() {
	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f asmb\n", obj.Cputime())
	}
	ld.Bso.Flush()

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f codeblk\n", obj.Cputime())
	}
	ld.Bso.Flush()

	if ld.Iself {
		ld.Asmbelfsetup()
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	ld.Codeblk(int64(sect.Vaddr), int64(sect.Length))
	for sect = sect.Next; sect != nil; sect = sect.Next {
		ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
		ld.Datblk(int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f rodatblk\n", obj.Cputime())
		}
		ld.Bso.Flush()

		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}

	if ld.Debug['v'] != 0 {
		fmt.Fprintf(&ld.Bso, "%5.2f datblk\n", obj.Cputime())
	}
	ld.Bso.Flush()

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	machlink := int64(0)
	if ld.HEADTYPE == obj.Hdarwin {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f dwarf\n", obj.Cputime())
		}

		dwarfoff := ld.Rnd(int64(uint64(ld.HEADR)+ld.Segtext.Length), int64(ld.INITRND)) + ld.Rnd(int64(ld.Segdata.Filelen), int64(ld.INITRND))
		ld.Cseek(dwarfoff)

		ld.Segdwarf.Fileoff = uint64(ld.Cpos())
		ld.Dwarfemitdebugsections()
		ld.Segdwarf.Filelen = uint64(ld.Cpos()) - ld.Segdwarf.Fileoff

		machlink = ld.Domacholink()
	}

	switch ld.HEADTYPE {
	default:
		ld.Diag("unknown header type %d", ld.HEADTYPE)
		fallthrough

	case obj.Hplan9,
		obj.Helf:
		break

	case obj.Hdarwin:
		ld.Debug['8'] = 1 /* 64-bit addresses */

	case obj.Hlinux,
		obj.Hfreebsd,
		obj.Hnetbsd,
		obj.Hopenbsd,
		obj.Hdragonfly,
		obj.Hsolaris:
		ld.Debug['8'] = 1 /* 64-bit addresses */

	case obj.Hnacl,
		obj.Hwindows:
		break
	}

	ld.Symsize = 0
	ld.Spsize = 0
	ld.Lcsize = 0
	symo := int64(0)
	if ld.Debug['s'] == 0 {
		if ld.Debug['v'] != 0 {
			fmt.Fprintf(&ld.Bso, "%5.2f sym\n", obj.Cputime())
		}
		ld.Bso.Flush()
		switch ld.HEADTYPE {
		default:
		case obj.Hplan9,
			obj.Helf:
			ld.Debug['s'] = 1
			symo = int64(ld.Segdata.Fileoff + ld.Segdata.Filelen)

		case obj.Hdarwin:
			symo = int64(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(ld.INITRND))) + uint64(machlink))
//.........這裏部分代碼省略.........

func asmb(ctxt *ld.Link) {
	if ctxt.Debugvlog != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f asmb\n", obj.Cputime())
	}
	ctxt.Bso.Flush()

	if ld.Iself {
		ld.Asmbelfsetup(ctxt)
	}

	sect := ld.Segtext.Sect
	ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
	// 0xCC is INT $3 - breakpoint instruction
	ld.CodeblkPad(ctxt, int64(sect.Vaddr), int64(sect.Length), []byte{0xCC})
	for sect = sect.Next; sect != nil; sect = sect.Next {
		ld.Cseek(int64(sect.Vaddr - ld.Segtext.Vaddr + ld.Segtext.Fileoff))
		ld.Datblk(ctxt, int64(sect.Vaddr), int64(sect.Length))
	}

	if ld.Segrodata.Filelen > 0 {
		if ctxt.Debugvlog != 0 {
			fmt.Fprintf(ctxt.Bso, "%5.2f rodatblk\n", obj.Cputime())
		}
		ctxt.Bso.Flush()

		ld.Cseek(int64(ld.Segrodata.Fileoff))
		ld.Datblk(ctxt, int64(ld.Segrodata.Vaddr), int64(ld.Segrodata.Filelen))
	}

	if ctxt.Debugvlog != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f datblk\n", obj.Cputime())
	}
	ctxt.Bso.Flush()

	ld.Cseek(int64(ld.Segdata.Fileoff))
	ld.Datblk(ctxt, int64(ld.Segdata.Vaddr), int64(ld.Segdata.Filelen))

	ld.Cseek(int64(ld.Segdwarf.Fileoff))
	ld.Dwarfblk(ctxt, int64(ld.Segdwarf.Vaddr), int64(ld.Segdwarf.Filelen))

	machlink := uint32(0)
	if ld.HEADTYPE == obj.Hdarwin {
		machlink = uint32(ld.Domacholink(ctxt))
	}

	ld.Symsize = 0
	ld.Spsize = 0
	ld.Lcsize = 0
	symo := uint32(0)
	if !*ld.FlagS {
		// TODO: rationalize
		if ctxt.Debugvlog != 0 {
			fmt.Fprintf(ctxt.Bso, "%5.2f sym\n", obj.Cputime())
		}
		ctxt.Bso.Flush()
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
				symo = uint32(ld.Rnd(int64(symo), int64(*ld.FlagRound)))
			}

		case obj.Hplan9:
			symo = uint32(ld.Segdata.Fileoff + ld.Segdata.Filelen)

		case obj.Hdarwin:
			symo = uint32(ld.Segdwarf.Fileoff + uint64(ld.Rnd(int64(ld.Segdwarf.Filelen), int64(*ld.FlagRound))) + uint64(machlink))

		case obj.Hwindows:
			symo = uint32(ld.Segdwarf.Fileoff + ld.Segdwarf.Filelen)
			symo = uint32(ld.Rnd(int64(symo), ld.PEFILEALIGN))
		}

		ld.Cseek(int64(symo))
		switch ld.HEADTYPE {
		default:
			if ld.Iself {
				if ctxt.Debugvlog != 0 {
					fmt.Fprintf(ctxt.Bso, "%5.2f elfsym\n", obj.Cputime())
				}
				ld.Asmelfsym(ctxt)
				ld.Cflush()
				ld.Cwrite(ld.Elfstrdat)

				if ld.Linkmode == ld.LinkExternal {
					ld.Elfemitreloc(ctxt)
				}
			}

		case obj.Hplan9:
			ld.Asmplan9sym(ctxt)
			ld.Cflush()

			sym := ld.Linklookup(ctxt, "pclntab", 0)
			if sym != nil {
				ld.Lcsize = int32(len(sym.P))
				for i := 0; int32(i) < ld.Lcsize; i++ {
					ld.Cput(sym.P[i])
				}

//.........這裏部分代碼省略.........

func ldshlibsyms(shlib string) {
	found := false
	libpath := ""
	for _, libdir := range Ctxt.Libdir {
		libpath = filepath.Join(libdir, shlib)
		if _, err := os.Stat(libpath); err == nil {
			found = true
			break
		}
	}
	if !found {
		Diag("cannot find shared library: %s", shlib)
		return
	}
	for _, processedname := range Ctxt.Shlibs {
		if processedname == libpath {
			return
		}
	}
	if Ctxt.Debugvlog > 1 && Ctxt.Bso != nil {
		fmt.Fprintf(Ctxt.Bso, "%5.2f ldshlibsyms: found library with name %s at %s\n", obj.Cputime(), shlib, libpath)
		Bflush(Ctxt.Bso)
	}

	f, err := elf.Open(libpath)
	if err != nil {
		Diag("cannot open shared library: %s", libpath)
		return
	}
	defer f.Close()
	syms, err := f.DynamicSymbols()
	if err != nil {
		Diag("cannot read symbols from shared library: %s", libpath)
		return
	}
	for _, s := range syms {
		if elf.ST_TYPE(s.Info) == elf.STT_NOTYPE || elf.ST_TYPE(s.Info) == elf.STT_SECTION {
			continue
		}
		if s.Section == elf.SHN_UNDEF {
			continue
		}
		if strings.HasPrefix(s.Name, "_") {
			continue
		}
		lsym := Linklookup(Ctxt, s.Name, 0)
		if lsym.Type != 0 && lsym.Dupok == 0 {
			Diag(
				"Found duplicate symbol %s reading from %s, first found in %s",
				s.Name, shlib, lsym.File)
		}
		lsym.Type = SDYNIMPORT
		lsym.File = libpath
	}

	// We might have overwritten some functions above (this tends to happen for the
	// autogenerated type equality/hashing functions) and we don't want to generated
	// pcln table entries for these any more so unstitch them from the Textp linked
	// list.
	var last *LSym

	for s := Ctxt.Textp; s != nil; s = s.Next {
		if s.Type == SDYNIMPORT {
			continue
		}

		if last == nil {
			Ctxt.Textp = s
		} else {
			last.Next = s
		}
		last = s
	}

	if last == nil {
		Ctxt.Textp = nil
		Ctxt.Etextp = nil
	} else {
		last.Next = nil
		Ctxt.Etextp = last
	}

	Ctxt.Shlibs = append(Ctxt.Shlibs, libpath)
}

//.........這裏部分代碼省略.........
		off = funcstart

		end = funcstart + int32(Thearch.Ptrsize) + 3*4 + 5*4 + int32(pcln.Npcdata)*4 + int32(pcln.Nfuncdata)*int32(Thearch.Ptrsize)
		if pcln.Nfuncdata > 0 && (end&int32(Thearch.Ptrsize-1) != 0) {
			end += 4
		}
		Symgrow(Ctxt, ftab, int64(end))

		// entry uintptr
		off = int32(setaddr(Ctxt, ftab, int64(off), Ctxt.Cursym))

		// name int32
		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(ftabaddstring(ftab, Ctxt.Cursym.Name))))

		// args int32
		// TODO: Move into funcinfo.
		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(Ctxt.Cursym.Args)))

		// frame int32
		// This has been removed (it was never set quite correctly anyway).
		// Nothing should use it.
		// Leave an obviously incorrect value.
		// TODO: Remove entirely.
		off = int32(setuint32(Ctxt, ftab, int64(off), 0x1234567))

		if pcln != &pclntab_zpcln {
			renumberfiles(Ctxt, pcln.File, &pcln.Pcfile)
			if false {
				// Sanity check the new numbering
				for pciterinit(Ctxt, &it, &pcln.Pcfile); it.done == 0; pciternext(&it) {
					if it.value < 1 || it.value > Ctxt.Nhistfile {
						Diag("bad file number in pcfile: %d not in range [1, %d]\n", it.value, Ctxt.Nhistfile)
						errorexit()
					}
				}
			}
		}

		// pcdata
		off = addpctab(ftab, off, &pcln.Pcsp)

		off = addpctab(ftab, off, &pcln.Pcfile)
		off = addpctab(ftab, off, &pcln.Pcline)
		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(pcln.Npcdata)))
		off = int32(setuint32(Ctxt, ftab, int64(off), uint32(pcln.Nfuncdata)))
		for i = 0; i < int32(pcln.Npcdata); i++ {
			off = addpctab(ftab, off, &pcln.Pcdata[i])
		}

		// funcdata, must be pointer-aligned and we're only int32-aligned.
		// Missing funcdata will be 0 (nil pointer).
		if pcln.Nfuncdata > 0 {
			if off&int32(Thearch.Ptrsize-1) != 0 {
				off += 4
			}
			for i = 0; i < int32(pcln.Nfuncdata); i++ {
				if pcln.Funcdata[i] == nil {
					setuintxx(Ctxt, ftab, int64(off)+int64(Thearch.Ptrsize)*int64(i), uint64(pcln.Funcdataoff[i]), int64(Thearch.Ptrsize))
				} else {
					// TODO: Dedup.
					funcdata_bytes += pcln.Funcdata[i].Size

					setaddrplus(Ctxt, ftab, int64(off)+int64(Thearch.Ptrsize)*int64(i), pcln.Funcdata[i], pcln.Funcdataoff[i])
				}
			}

			off += int32(pcln.Nfuncdata) * int32(Thearch.Ptrsize)
		}

		if off != end {
			Diag("bad math in functab: funcstart=%d off=%d but end=%d (npcdata=%d nfuncdata=%d ptrsize=%d)", funcstart, off, end, pcln.Npcdata, pcln.Nfuncdata, Thearch.Ptrsize)
			errorexit()
		}

		nfunc++
	}

	pclntabLastFunc = last
	// Final entry of table is just end pc.
	setaddrplus(Ctxt, ftab, 8+int64(Thearch.Ptrsize)+int64(nfunc)*2*int64(Thearch.Ptrsize), last, last.Size)

	// Start file table.
	start := int32(len(ftab.P))

	start += int32(-len(ftab.P)) & (int32(Thearch.Ptrsize) - 1)
	pclntabFiletabOffset = start
	setuint32(Ctxt, ftab, 8+int64(Thearch.Ptrsize)+int64(nfunc)*2*int64(Thearch.Ptrsize)+int64(Thearch.Ptrsize), uint32(start))

	Symgrow(Ctxt, ftab, int64(start)+(int64(Ctxt.Nhistfile)+1)*4)
	setuint32(Ctxt, ftab, int64(start), uint32(Ctxt.Nhistfile))
	for s := Ctxt.Filesyms; s != nil; s = s.Next {
		setuint32(Ctxt, ftab, int64(start)+s.Value*4, uint32(ftabaddstring(ftab, s.Name)))
	}

	ftab.Size = int64(len(ftab.P))

	if Debug['v'] != 0 {
		fmt.Fprintf(&Bso, "%5.2f pclntab=%d bytes, funcdata total %d bytes\n", obj.Cputime(), int64(ftab.Size), int64(funcdata_bytes))
	}
}

/*
 * This is the main entry point for generating dwarf.  After emitting
 * the mandatory debug_abbrev section, it calls writelines() to set up
 * the per-compilation unit part of the DIE tree, while simultaneously
 * emitting the debug_line section.  When the final tree contains
 * forward references, it will write the debug_info section in 2
 * passes.
 *
 */
func dwarfgeneratedebugsyms(ctxt *Link) {
	if *FlagW { // disable dwarf
		return
	}
	if *FlagS && HEADTYPE != obj.Hdarwin {
		return
	}
	if HEADTYPE == obj.Hplan9 {
		return
	}

	if Linkmode == LinkExternal {
		if !Iself && HEADTYPE != obj.Hdarwin {
			return
		}
	}

	if ctxt.Debugvlog != 0 {
		fmt.Fprintf(ctxt.Bso, "%5.2f dwarf\n", obj.Cputime())
	}

	// Forctxt.Diagnostic messages.
	newattr(&dwtypes, dwarf.DW_AT_name, dwarf.DW_CLS_STRING, int64(len("dwtypes")), "dwtypes")

	// Some types that must exist to define other ones.
	newdie(ctxt, &dwtypes, dwarf.DW_ABRV_NULLTYPE, "<unspecified>", 0)

	newdie(ctxt, &dwtypes, dwarf.DW_ABRV_NULLTYPE, "void", 0)
	newdie(ctxt, &dwtypes, dwarf.DW_ABRV_BARE_PTRTYPE, "unsafe.Pointer", 0)

	die := newdie(ctxt, &dwtypes, dwarf.DW_ABRV_BASETYPE, "uintptr", 0) // needed for array size
	newattr(die, dwarf.DW_AT_encoding, dwarf.DW_CLS_CONSTANT, dwarf.DW_ATE_unsigned, 0)
	newattr(die, dwarf.DW_AT_byte_size, dwarf.DW_CLS_CONSTANT, int64(SysArch.PtrSize), 0)
	newattr(die, dwarf.DW_AT_go_kind, dwarf.DW_CLS_CONSTANT, obj.KindUintptr, 0)

	// Prototypes needed for type synthesis.
	prototypedies = map[string]*dwarf.DWDie{
		"type.runtime.stringStructDWARF": nil,
		"type.runtime.slice":             nil,
		"type.runtime.hmap":              nil,
		"type.runtime.bmap":              nil,
		"type.runtime.sudog":             nil,
		"type.runtime.waitq":             nil,
		"type.runtime.hchan":             nil,
	}

	// Needed by the prettyprinter code for interface inspection.
	defgotype(ctxt, lookup_or_diag(ctxt, "type.runtime._type"))

	defgotype(ctxt, lookup_or_diag(ctxt, "type.runtime.interfacetype"))
	defgotype(ctxt, lookup_or_diag(ctxt, "type.runtime.itab"))

	genasmsym(ctxt, defdwsymb)

	syms := writeabbrev(ctxt, nil)
	syms, funcs := writelines(ctxt, syms)
	syms = writeframes(ctxt, syms)

	synthesizestringtypes(ctxt, dwtypes.Child)
	synthesizeslicetypes(ctxt, dwtypes.Child)
	synthesizemaptypes(ctxt, dwtypes.Child)
	synthesizechantypes(ctxt, dwtypes.Child)

	reversetree(&dwroot.Child)
	reversetree(&dwtypes.Child)
	reversetree(&dwglobals.Child)

	movetomodule(&dwtypes)
	movetomodule(&dwglobals)

	// Need to reorder symbols so SDWARFINFO is after all SDWARFSECT
	// (but we need to generate dies before writepub)
	infosyms := writeinfo(ctxt, nil, funcs)

	syms = writepub(ctxt, ".debug_pubnames", ispubname, syms)
	syms = writepub(ctxt, ".debug_pubtypes", ispubtype, syms)
	syms = writearanges(ctxt, syms)
	syms = writegdbscript(ctxt, syms)
	syms = append(syms, infosyms...)
	dwarfp = syms
}