loader.go

			return s
		}
		s := l.allocSym(name, ver)
		l.installSym(i, s)
		syms.Allsym = append(syms.Allsym, s) // XXX see above
		return s
	}
	syms.ROLookup = func(name string, ver int) *sym.Symbol {
		i := l.Lookup(name, ver)
		return l.Syms[i]
	}
	syms.Rename = func(old, new string, ver int) {
		// annoying... maybe there is a better way to do this
		if ver >= 2 {
			panic("cannot rename static symbol")
		}
		i := l.Lookup(old, ver)
		s := l.Syms[i]
		s.Name = new
		if s.Extname() == old {
			s.SetExtname(new)
		}
		delete(l.symsByName[ver], old)

		// This mirrors the old code. But I'm not sure if the logic of
		// handling dup in the old code actually works, or necessary.
		dupi := l.symsByName[ver][new]
		dup := l.Syms[dupi]
		if dup == nil {
			l.symsByName[ver][new] = i
		} else {
			if s.Type == 0 {
				dup.Attr |= s.Attr
				*s = *dup
			} else if dup.Type == 0 {
				s.Attr |= dup.Attr
				*dup = *s
				l.symsByName[ver][new] = i
			}
		}
	}
}

// allocSym allocates a new symbol backing.
func (l *Loader) allocSym(name string, version int) *sym.Symbol {
	batch := l.symBatch
	if len(batch) == 0 {
		batch = make([]sym.Symbol, 1000)
	}
	s := &batch[0]
	l.symBatch = batch[1:]

	s.Dynid = -1
	s.Name = name
	s.Version = int16(version)

	return s
}

// installSym sets the underlying sym.Symbol for the specified sym index.
func (l *Loader) installSym(i Sym, s *sym.Symbol) {
	if s == nil {
		panic("installSym nil symbol")
	}
	if l.Syms[i] != nil {
		panic("sym already present in installSym")
	}
	l.Syms[i] = s
}

// addNewSym adds a new sym.Symbol to the i-th index in the list of symbols.
func (l *Loader) addNewSym(i Sym, name string, ver int, unit *sym.CompilationUnit, t sym.SymKind) *sym.Symbol {
	s := l.allocSym(name, ver)
	if s.Type != 0 && s.Type != sym.SXREF {
		fmt.Println("symbol already processed:", unit.Lib, i, s)
		panic("symbol already processed")
	}
	if t == sym.SBSS && (s.Type == sym.SRODATA || s.Type == sym.SNOPTRBSS) {
		t = s.Type
	}
	s.Type = t
	s.Unit = unit
	l.growSyms(int(i))
	l.installSym(i, s)
	return s
}

// loadObjSyms creates sym.Symbol objects for the live Syms in the
// object corresponding to object reader "r". Return value is the
// number of sym.Reloc entries required for all the new symbols.
func loadObjSyms(l *Loader, syms *sym.Symbols, r *oReader) int {
	nr := 0
	for i, n := 0, r.NSym()+r.NNonpkgdef(); i < n; i++ {
		gi := r.syms[i]
		if r2, i2 := l.toLocal(gi); r2 != r || i2 != i {
			continue // come from a different object
		}
		osym := goobj2.Sym{}
		osym.Read(r.Reader, r.SymOff(i))
		name := strings.Replace(osym.Name, "\"\".", r.pkgprefix, -1)
		if name == "" {
			continue
		}
		ver := abiToVer(osym.ABI, r.version)
		t := sym.AbiSymKindToSymKind[objabi.SymKind(osym.Type)]
		if t == sym.SXREF {
			log.Fatalf("bad sxref")
		}
		if t == 0 {
			log.Fatalf("missing type for %s in %s", name, r.unit.Lib)
		}
		if !l.attrReachable.Has(gi) && name != "runtime.addmoduledata" && name != "runtime.lastmoduledatap" {
			// No need to load unreachable symbols.
			// XXX reference to runtime.addmoduledata may be generated later by the linker in plugin mode.
			continue
		}

		s := l.addNewSym(gi, name, ver, r.unit, t)
		l.migrateAttributes(gi, s)
		nr += r.NReloc(i)
	}
	return nr
}

// funcInfoSym records the sym.Symbol for a function, along with a copy
// of the corresponding goobj2.Sym and the index of its FuncInfo aux sym.
// We use this to delay populating FuncInfo until we can batch-allocate
// slices for their sub-objects.
type funcInfoSym struct {
	s    *sym.Symbol // sym.Symbol for a live function
	osym goobj2.Sym  // object file symbol data for that function
	isym int         // global symbol index of FuncInfo aux sym for func
}

// funcAllocInfo records totals/counts for all functions in an objfile;
// used to help with bulk allocation of sym.Symbol sub-objects.
type funcAllocInfo struct {
	symPtr  uint32 // number of *sym.Symbol's needed in file slices
	inlCall uint32 // number of sym.InlinedCall's needed in inltree slices
	pcData  uint32 // number of sym.Pcdata's needed in pdata slices
	fdOff   uint32 // number of int64's needed in all Funcdataoff slices
}

// cloneToExternal takes the existing object file symbol (symIdx)
// and creates a new external symbol payload that is a clone with
// respect to name, version, type, relocations, etc. The idea here
// is that if the linker decides it wants to update the contents of
// a symbol originally discovered as part of an object file, it's
// easier to do this if we make the updates to an external symbol
// payload.
// XXX maybe rename? makeExtPayload?
func (l *Loader) cloneToExternal(symIdx Sym) {
	if l.IsExternal(symIdx) {
		panic("sym is already external, no need for clone")
	}
	l.growSyms(int(symIdx))

	// Read the particulars from object.
	osym := goobj2.Sym{}
	r, li := l.toLocal(symIdx)
	osym.Read(r.Reader, r.SymOff(li))
	sname := strings.Replace(osym.Name, "\"\".", r.pkgprefix, -1)
	sver := abiToVer(osym.ABI, r.version)
	skind := sym.AbiSymKindToSymKind[objabi.SymKind(osym.Type)]

	// Create new symbol, update version and kind.
	pi := l.newPayload(sname, sver)
	pp := l.payloads[pi]
	pp.kind = skind
	pp.ver = sver
	pp.size = int64(osym.Siz)
	pp.objidx = r.objidx

	// If this is a def, then copy the guts. We expect this case
	// to be very rare (one case it may come up is with -X).
	if li < (r.NSym() + r.NNonpkgdef()) {

		// Copy relocations
		relocs := l.Relocs(symIdx)
		pp.relocs = relocs.ReadAll(nil)

		// Copy data
		pp.data = r.Data(li)
	}

	// If we're overriding a data symbol, collect the associated
	// Gotype, so as to propagate it to the new symbol.
	naux := r.NAux(li)
	for j := 0; j < naux; j++ {
		a := goobj2.Aux{}
		a.Read(r.Reader, r.AuxOff(li, j))
		switch a.Type {
		case goobj2.AuxGotype:
			pp.gotype = l.resolve(r, a.Sym)
		default:
			log.Fatalf("internal error: cloneToExternal applied to %s symbol %s with non-gotype aux data %d", skind.String(), sname, a.Type)
		}
	}

	// Install new payload to global index space.
	// (This needs to happen at the end, as the accessors above
	// need to access the old symbol content.)
	l.objSyms[symIdx] = objSym{l.extReader, pi}
	l.extReader.syms = append(l.extReader.syms, symIdx)
}

// copyAttributes copies over all of the attributes of symbol 'src' to
// symbol 'dst'. The assumption is that 'dst' is an external symbol.
func (l *Loader) copyAttributes(src Sym, dst Sym) {
	l.SetAttrReachable(dst, l.AttrReachable(src))
	l.SetAttrOnList(dst, l.AttrOnList(src))
	l.SetAttrLocal(dst, l.AttrLocal(src))
	l.SetAttrNotInSymbolTable(dst, l.AttrNotInSymbolTable(src))
	l.SetAttrVisibilityHidden(dst, l.AttrVisibilityHidden(src))
	l.SetAttrDuplicateOK(dst, l.AttrDuplicateOK(src))
	l.SetAttrShared(dst, l.AttrShared(src))
	l.SetAttrExternal(dst, l.AttrExternal(src))
	l.SetAttrTopFrame(dst, l.AttrTopFrame(src))
	l.SetAttrSpecial(dst, l.AttrSpecial(src))
	l.SetAttrCgoExportDynamic(dst, l.AttrCgoExportDynamic(src))
	l.SetAttrCgoExportStatic(dst, l.AttrCgoExportStatic(src))
	l.SetAttrReadOnly(dst, l.AttrReadOnly(src))
}

// migrateAttributes copies over all of the attributes of symbol 'src' to
// sym.Symbol 'dst'.
func (l *Loader) migrateAttributes(src Sym, dst *sym.Symbol) {
	dst.Attr.Set(sym.AttrReachable, l.AttrReachable(src))
	dst.Attr.Set(sym.AttrOnList, l.AttrOnList(src))
	dst.Attr.Set(sym.AttrLocal, l.AttrLocal(src))
	dst.Attr.Set(sym.AttrNotInSymbolTable, l.AttrNotInSymbolTable(src))
	dst.Attr.Set(sym.AttrNoSplit, l.IsNoSplit(src))
	dst.Attr.Set(sym.AttrVisibilityHidden, l.AttrVisibilityHidden(src))
	dst.Attr.Set(sym.AttrDuplicateOK, l.AttrDuplicateOK(src))
	dst.Attr.Set(sym.AttrShared, l.AttrShared(src))
	dst.Attr.Set(sym.AttrExternal, l.AttrExternal(src))
	dst.Attr.Set(sym.AttrTopFrame, l.AttrTopFrame(src))
	dst.Attr.Set(sym.AttrSpecial, l.AttrSpecial(src))
	dst.Attr.Set(sym.AttrCgoExportDynamic, l.AttrCgoExportDynamic(src))
	dst.Attr.Set(sym.AttrCgoExportStatic, l.AttrCgoExportStatic(src))
	dst.Attr.Set(sym.AttrReadOnly, l.AttrReadOnly(src))

	// Convert outer/sub relationships
	if outer, ok := l.outer[src]; ok {
		dst.Outer = l.Syms[outer]
	}
	if sub, ok := l.sub[src]; ok {
		dst.Sub = l.Syms[sub]
	}

	// Set sub-symbol attribute. FIXME: would be better to do away
	// with this and just use l.OuterSymbol() != 0 elsewhere within
	// the linker.
	dst.Attr.Set(sym.AttrSubSymbol, dst.Outer != nil)

	// Copy over dynimplib, dynimpvers, extname.
	if l.SymExtname(src) != "" {
		dst.SetExtname(l.SymExtname(src))
	}
	if l.SymDynimplib(src) != "" {
		dst.SetDynimplib(l.SymDynimplib(src))
	}
	if l.SymDynimpvers(src) != "" {
		dst.SetDynimpvers(l.SymDynimpvers(src))
	}

	// Copy ELF type if set.
	if et, ok := l.elfType[src]; ok {
		dst.SetElfType(et)
	}

	// Copy pe objects values if set.
	if plt, ok := l.plt[src]; ok {
		dst.SetPlt(plt)
	}
	if got, ok := l.got[src]; ok {
		dst.SetGot(got)
	}
}

// CreateExtSym creates a new external symbol with the specified name
// without adding it to any lookup tables, returning a Sym index for it.
func (l *Loader) CreateExtSym(name string) Sym {
	// Assign a new unique negative version -- this is to mark the
	// symbol so that it can be skipped when ExtractSymbols is adding
	// ext syms to the sym.Symbols hash.
	l.anonVersion--
	return l.newExtSym(name, l.anonVersion)
}

func loadObjFull(l *Loader, r *oReader) {
	lib := r.unit.Lib
	resolveSymRef := func(s goobj2.SymRef) *sym.Symbol {
		i := l.resolve(r, s)
		return l.Syms[i]
	}

	funcs := []funcInfoSym{}
	fdsyms := []*sym.Symbol{}
	var funcAllocCounts funcAllocInfo
	pcdataBase := r.PcdataBase()
	rslice := []Reloc{}
	for i, n := 0, r.NSym()+r.NNonpkgdef(); i < n; i++ {
		// A symbol may be a dup or overwritten. In this case, its
		// content will actually be provided by a different object
		// (to which its global index points). Skip those symbols.
		gi := l.toGlobal(r, i)
		var isdup bool
		if r2, i2 := l.toLocal(gi); r2 != r || i2 != i {
			isdup = true
		}

		osym := goobj2.Sym{}
		osym.ReadWithoutName(r.Reader, r.SymOff(i))
		dupok := osym.Dupok()
		if dupok && isdup {
			if l.attrReachable.Has(gi) {
				// A dupok symbol is resolved to another package. We still need
				// to record its presence in the current package, as the trampoline
				// pass expects packages are laid out in dependency order.
				s := l.Syms[gi]
				if s.Type == sym.STEXT {
					lib.DupTextSyms = append(lib.DupTextSyms, s)
				}
			}
			continue
		}

		if isdup {
			continue // come from a different object
		}
		s := l.Syms[gi]
		if s == nil {
			continue
		}

		local := osym.Local()
		makeTypelink := osym.Typelink()
		size := osym.Siz

		// Symbol data
		s.P = r.Data(i)
		s.Attr.Set(sym.AttrReadOnly, r.ReadOnly())

		// Relocs
		relocs := l.relocs(r, i)
		rslice = relocs.ReadAll(rslice)
		batch := l.relocBatch
		s.R = batch[:relocs.Count:relocs.Count]
		l.relocBatch = batch[relocs.Count:]
		l.convertRelocations(rslice, s, false)

		// Aux symbol info
		isym := -1
		naux := r.NAux(i)
		for j := 0; j < naux; j++ {
			a := goobj2.Aux{}
			a.Read(r.Reader, r.AuxOff(i, j))
			switch a.Type {
			case goobj2.AuxGotype:
				typ := resolveSymRef(a.Sym)
				if typ != nil {
					s.Gotype = typ
				}
			case goobj2.AuxFuncdata:
				fdsyms = append(fdsyms, resolveSymRef(a.Sym))
			case goobj2.AuxFuncInfo:
				if a.Sym.PkgIdx != goobj2.PkgIdxSelf {
					panic("funcinfo symbol not defined in current package")
				}
				isym = int(a.Sym.SymIdx)
			case goobj2.AuxDwarfInfo, goobj2.AuxDwarfLoc, goobj2.AuxDwarfRanges, goobj2.AuxDwarfLines:
				// ignored for now
			default:
				panic("unknown aux type")
			}
		}

		s.File = r.pkgprefix[:len(r.pkgprefix)-1]
		if dupok {
			s.Attr |= sym.AttrDuplicateOK
		}
		if s.Size < int64(size) {
			s.Size = int64(size)
		}
		s.Attr.Set(sym.AttrLocal, local)
		s.Attr.Set(sym.AttrMakeTypelink, makeTypelink)

		if s.Type != sym.STEXT {
			continue
		}

		if isym == -1 {
			continue
		}

		// Record function sym and associated info for additional
		// processing in the loop below.
		fwis := funcInfoSym{s: s, isym: isym, osym: osym}
		funcs = append(funcs, fwis)

		// Read the goobj2.FuncInfo for this text symbol so that we can
		// collect allocation counts. We'll read it again in the loop
		// below.
		b := r.Data(isym)
		info := goobj2.FuncInfo{}
		info.Read(b)
		funcAllocCounts.symPtr += uint32(len(info.File))
		funcAllocCounts.pcData += uint32(len(info.Pcdata))
		funcAllocCounts.inlCall += uint32(len(info.InlTree))
		funcAllocCounts.fdOff += uint32(len(info.Funcdataoff))
	}

	// At this point we can do batch allocation of the sym.FuncInfo's,
	// along with the slices of sub-objects they use.
	fiBatch := make([]sym.FuncInfo, len(funcs))
	inlCallBatch := make([]sym.InlinedCall, funcAllocCounts.inlCall)
	symPtrBatch := make([]*sym.Symbol, funcAllocCounts.symPtr)
	pcDataBatch := make([]sym.Pcdata, funcAllocCounts.pcData)
	fdOffBatch := make([]int64, funcAllocCounts.fdOff)

	// Populate FuncInfo contents for func symbols.
	for fi := 0; fi < len(funcs); fi++ {
		s := funcs[fi].s
		isym := funcs[fi].isym
		osym := funcs[fi].osym

		s.FuncInfo = &fiBatch[0]
		fiBatch = fiBatch[1:]

		b := r.Data(isym)
		info := goobj2.FuncInfo{}
		info.Read(b)

		if osym.NoSplit() {
			s.Attr |= sym.AttrNoSplit
		}
		if osym.ReflectMethod() {
			s.Attr |= sym.AttrReflectMethod
		}
		if r.Flags()&goobj2.ObjFlagShared != 0 {
			s.Attr |= sym.AttrShared
		}
		if osym.TopFrame() {
			s.Attr |= sym.AttrTopFrame
		}

		pc := s.FuncInfo

		if len(info.Funcdataoff) != 0 {
			nfd := len(info.Funcdataoff)
			pc.Funcdata = fdsyms[:nfd:nfd]
			fdsyms = fdsyms[nfd:]
		}

		info.Pcdata = append(info.Pcdata, info.PcdataEnd) // for the ease of knowing where it ends
		pc.Args = int32(info.Args)
		pc.Locals = int32(info.Locals)

		npc := len(info.Pcdata) - 1 // -1 as we appended one above
		pc.Pcdata = pcDataBatch[:npc:npc]
		pcDataBatch = pcDataBatch[npc:]

		nfd := len(info.Funcdataoff)
		pc.Funcdataoff = fdOffBatch[:nfd:nfd]
		fdOffBatch = fdOffBatch[nfd:]

		nsp := len(info.File)
		pc.File = symPtrBatch[:nsp:nsp]
		symPtrBatch = symPtrBatch[nsp:]

		nic := len(info.InlTree)
		pc.InlTree = inlCallBatch[:nic:nic]
		inlCallBatch = inlCallBatch[nic:]

		pc.Pcsp.P = r.BytesAt(pcdataBase+info.Pcsp, int(info.Pcfile-info.Pcsp))
		pc.Pcfile.P = r.BytesAt(pcdataBase+info.Pcfile, int(info.Pcline-info.Pcfile))
		pc.Pcline.P = r.BytesAt(pcdataBase+info.Pcline, int(info.Pcinline-info.Pcline))
		pc.Pcinline.P = r.BytesAt(pcdataBase+info.Pcinline, int(info.Pcdata[0]-info.Pcinline))
		for k := range pc.Pcdata {
			pc.Pcdata[k].P = r.BytesAt(pcdataBase+info.Pcdata[k], int(info.Pcdata[k+1]-info.Pcdata[k]))
		}
		for k := range pc.Funcdataoff {
			pc.Funcdataoff[k] = int64(info.Funcdataoff[k])
		}
		for k := range pc.File {
			pc.File[k] = resolveSymRef(info.File[k])
		}
		for k := range pc.InlTree {
			inl := &info.InlTree[k]
			pc.InlTree[k] = sym.InlinedCall{
				Parent:   inl.Parent,
				File:     resolveSymRef(inl.File),
				Line:     inl.Line,
				Func:     l.SymName(l.resolve(r, inl.Func)),
				ParentPC: inl.ParentPC,
			}
		}

		dupok := osym.Dupok()
		if !dupok {
			if s.Attr.OnList() {
				log.Fatalf("symbol %s listed multiple times", s.Name)
			}
			s.Attr.Set(sym.AttrOnList, true)
			lib.Textp = append(lib.Textp, s)
		} else {
			// there may be a dup in another package
			// put into a temp list and add to text later
			lib.DupTextSyms = append(lib.DupTextSyms, s)
		}
	}
}

// convertRelocations takes a vector of loader.Reloc relocations and
// translates them into an equivalent set of sym.Reloc relocations on
// the symbol "dst", performing fixups along the way for ABI aliases,
// etc. It is assumed that the caller has pre-allocated the dst symbol
// relocations slice. If 'strict' is set, then this method will
// panic if it finds a relocation targeting a nil symbol.
func (l *Loader) convertRelocations(src []Reloc, dst *sym.Symbol, strict bool) {
	for j := range dst.R {
		r := src[j]
		rs := r.Sym
		sz := r.Size
		rt := r.Type
		if rt == objabi.R_METHODOFF {
			if l.attrReachable.Has(rs) {
				rt = objabi.R_ADDROFF
			} else {
				sz = 0
				rs = 0
			}
		}
		if rt == objabi.R_WEAKADDROFF && !l.attrReachable.Has(rs) {
			rs = 0
			sz = 0
		}
		if rs != 0 && l.Syms[rs] != nil && l.Syms[rs].Type == sym.SABIALIAS {
			rsrelocs := l.Relocs(rs)
			rs = rsrelocs.At(0).Sym
		}
		if strict && rs != 0 && l.Syms[rs] == nil && rt != objabi.R_USETYPE {
			panic("nil reloc target in convertRelocations")
		}
		dst.R[j] = sym.Reloc{
			Off:  r.Off,
			Siz:  sz,
			Type: rt,
			Add:  r.Add,
			Sym:  l.Syms[rs],
		}
	}
}

// UndefinedRelocTargets iterates through the global symbol index
// space, looking for symbols with relocations targeting undefined
// references. The linker's loadlib method uses this to determine if
// there are unresolved references to functions in system libraries
// (for example, libgcc.a), presumably due to CGO code. Return
// value is a list of loader.Sym's corresponding to the undefined
// cross-refs. The "limit" param controls the maximum number of
// results returned; if "limit" is -1, then all undefs are returned.
func (l *Loader) UndefinedRelocTargets(limit int) []Sym {
	result := []Sym{}
	rslice := []Reloc{}
	for si := Sym(1); si < Sym(len(l.objSyms)); si++ {
		relocs := l.Relocs(si)
		rslice = relocs.ReadSyms(rslice)
		for ri := 0; ri < relocs.Count; ri++ {
			r := &rslice[ri]
			if r.Sym != 0 && l.SymType(r.Sym) == sym.SXREF && l.RawSymName(r.Sym) != ".got" {
				result = append(result, r.Sym)
				if limit != -1 && len(result) >= limit {
					break
				}
			}
		}
	}
	return result
}

// AssignTextSymbolOrder populates the Textp2 slices within each
// library and compilation unit, insuring that packages are laid down
// in dependency order (internal first, then everything else). Return value
// is a slice of all text syms.
func (l *Loader) AssignTextSymbolOrder(libs []*sym.Library, intlibs []bool, extsyms []Sym) []Sym {

	// Library Textp2 lists should be empty at this point.
	for _, lib := range libs {
		if len(lib.Textp2) != 0 {
			panic("expected empty Textp2 slice for library")
		}
		if len(lib.DupTextSyms2) != 0 {
			panic("expected empty DupTextSyms2 slice for library")
		}
	}

	// Used to record which dupok symbol we've assigned to a unit.
	// Can't use the onlist attribute here because it will need to
	// clear for the later assignment of the sym.Symbol to a unit.
	// NB: we can convert to using onList once we no longer have to
	// call the regular addToTextp.
	assignedToUnit := MakeBitmap(l.NSym() + 1)

	// Start off textp2 with reachable external syms.
	textp2 := []Sym{}
	for _, sym := range extsyms {
		if !l.attrReachable.Has(sym) {
			continue
		}
		textp2 = append(textp2, sym)
	}

	// Walk through all text symbols from Go object files and append
	// them to their corresponding library's textp2 list.
	for _, o := range l.objs[1:] {
		r := o.r
		lib := r.unit.Lib
		for i, n := 0, r.NSym()+r.NNonpkgdef(); i < n; i++ {
			gi := l.toGlobal(r, i)
			if !l.attrReachable.Has(gi) {
				continue
			}
			osym := goobj2.Sym{}
			osym.ReadWithoutName(r.Reader, r.SymOff(i))
			st := sym.AbiSymKindToSymKind[objabi.SymKind(osym.Type)]
			if st != sym.STEXT {
				continue
			}
			dupok := osym.Dupok()
			if r2, i2 := l.toLocal(gi); r2 != r || i2 != i {
				// A dupok text symbol is resolved to another package.
				// We still need to record its presence in the current
				// package, as the trampoline pass expects packages
				// are laid out in dependency order.
				lib.DupTextSyms2 = append(lib.DupTextSyms2, sym.LoaderSym(gi))
				continue // symbol in different object
			}
			if dupok {
				lib.DupTextSyms2 = append(lib.DupTextSyms2, sym.LoaderSym(gi))
			}

			lib.Textp2 = append(lib.Textp2, sym.LoaderSym(gi))
		}
	}

	// Now redo the assignment of text symbols to libs/units.
	for _, doInternal := range [2]bool{true, false} {
		for idx, lib := range libs {
			if intlibs[idx] != doInternal {
				continue
			}
			libtextp2 := []sym.LoaderSym{}
			lists := [2][]sym.LoaderSym{lib.Textp2, lib.DupTextSyms2}
			for _, list := range lists {
				for _, s := range list {
					sym := Sym(s)
					if l.attrReachable.Has(sym) && !assignedToUnit.Has(sym) {
						libtextp2 = append(libtextp2, s)
						textp2 = append(textp2, sym)
						unit := l.SymUnit(sym)
						if unit != nil {
							unit.Textp2 = append(unit.Textp2, s)
							assignedToUnit.Set(sym)
						}
					}
				}
			}
			lib.Textp2 = libtextp2
		}
	}

	return textp2
}

// For debugging.
func (l *Loader) Dump() {
	fmt.Println("objs")
	for _, obj := range l.objs {
		if obj.r != nil {
			fmt.Println(obj.i, obj.r.unit.Lib)
		}
	}
	fmt.Println("extStart:", l.extStart)
	fmt.Println("Nsyms:", len(l.objSyms))
	fmt.Println("syms")
	for i := Sym(1); i < Sym(len(l.objSyms)); i++ {
		pi := interface{}("")
		if l.IsExternal(i) {
			pi = fmt.Sprintf("<ext %d>", l.extIndex(i))
		}
		var s *sym.Symbol
		if int(i) < len(l.Syms) {
			s = l.Syms[i]
		}
		if s != nil {
			fmt.Println(i, s, s.Type, pi)
		} else {
			fmt.Println(i, l.SymName(i), "<not loaded>", pi)
		}
	}
	fmt.Println("symsByName")
	for name, i := range l.symsByName[0] {
		fmt.Println(i, name, 0)
	}
	for name, i := range l.symsByName[1] {
		fmt.Println(i, name, 1)
	}
	fmt.Println("payloads:")
	for i := range l.payloads {
		pp := l.payloads[i]
		fmt.Println(i, pp.name, pp.ver, pp.kind)
	}
}