//
// Possible build modes are the same as those for the -buildmode flag
// in cmd/go, and are documented in 'go help buildmode'.
type BuildMode uint8

const (
	BuildModeUnset BuildMode = iota
	BuildModeExe
	BuildModePIE
	BuildModeCArchive
	BuildModeCShared
	BuildModeShared
	BuildModePlugin
)

// Set implements flag.Value to set the build mode based on the argument
// to the -buildmode flag.

	LinkMode  LinkMode
	BuildMode BuildMode

	linkShared    bool
	canUsePlugins bool
	IsELF         bool
}

//
// Target type functions
//

func (t *Target) IsExe() bool {
	return t.BuildMode == BuildModeExe
}

func (t *Target) IsShared() bool {
	return t.BuildMode == BuildModeShared
}

func (t *Target) IsPlugin() bool {
	return t.BuildMode == BuildModePlugin
}

func (t *Target) IsInternal() bool {

// records so that the order respects all the dependencies,
// and given that restriction, orders the inittasks in
// lexicographic order.
func (ctxt *Link) inittasks() {
	switch ctxt.BuildMode {
	case BuildModeExe, BuildModePIE, BuildModeCArchive, BuildModeCShared:
		// Normally the inittask list will be run on program startup.
		ctxt.mainInittasks = ctxt.inittaskSym([]string{"main..inittask"}, "go:main.inittasks")
	case BuildModePlugin:

	// functions and mark what is reachable from there.
	if d.ctxt.linkShared && (d.ctxt.BuildMode == BuildModeExe || d.ctxt.BuildMode == BuildModePIE) {
		names = append(names, "main.main", "main..inittask")
	} else {
		// The external linker refers main symbol directly.
		if d.ctxt.LinkMode == LinkExternal && (d.ctxt.BuildMode == BuildModeExe || d.ctxt.BuildMode == BuildModePIE) {

		moduledata.AddUint(ctxt.Arch, 0)
		moduledata.AddUint(ctxt.Arch, 0)
	}

	if len(ctxt.Shlibs) > 0 {
		thismodulename := filepath.Base(*flagOutfile)
		switch ctxt.BuildMode {
		case BuildModeExe, BuildModePIE:
			// When linking an executable, outfile is just "a.out". Make
			// it something slightly more comprehensible.
			thismodulename = "the executable"
		}

	f.xfhdr.Fnscns = uint16(len(f.sections))
	f.xfhdr.Ftimedat = 0

	if !*FlagS {
		f.xfhdr.Fsymptr = uint64(f.symtabOffset)
		f.xfhdr.Fnsyms = int32(f.symbolCount)
	}

	if ctxt.BuildMode == BuildModeExe && ctxt.LinkMode == LinkInternal {
		ldr := ctxt.loader
		f.xfhdr.Fopthdr = AOUTHSZ_EXEC64
		f.xfhdr.Fflags = F_EXEC

		// auxiliary header
		f.xahdr.Ovstamp = 1 // based on dump -o

	}

	if *flagEntrySymbol == "" {
		switch ctxt.BuildMode {
		case BuildModeCShared, BuildModeCArchive:
			*flagEntrySymbol = fmt.Sprintf("_rt0_%s_%s_lib", buildcfg.GOARCH, buildcfg.GOOS)
		case BuildModeExe, BuildModePIE:
			*flagEntrySymbol = fmt.Sprintf("_rt0_%s_%s", buildcfg.GOARCH, buildcfg.GOOS)
		case BuildModeShared, BuildModePlugin:
			// No *flagEntrySymbol for -buildmode=shared and plugin
		default:

	}

	pad := int64(cieReserve) + lengthFieldSize - int64(len(d.ldr.Data(fs)))

	if pad < 0 {
		Exitf("dwarf: cieReserve too small by %d bytes.", -pad)
	}

	internalExec := d.linkctxt.BuildMode == BuildModeExe && d.linkctxt.IsInternal()
	addAddrPlus := loader.GenAddAddrPlusFunc(internalExec)

	fsu.AddBytes(zeros[:pad])

	var deltaBuf []byte
	pcsp := obj.NewPCIter(uint32(d.arch.MinLC))