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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package loader
import (
"cmd/internal/goobj2"
"cmd/internal/objabi"
"cmd/internal/sys"
"cmd/link/internal/sym"
"fmt"
)
// SymbolBuilder is a helper designed to help with the construction
// of new symbol contents.
type SymbolBuilder struct {
*extSymPayload // points to payload being updated
symIdx Sym // index of symbol being updated/constructed
l *Loader // loader
}
// MakeSymbolBuilder creates a symbol builder for use in constructing
// an entirely new symbol.
func (l *Loader) MakeSymbolBuilder(name string) *SymbolBuilder {
// for now assume that any new sym is intended to be static
symIdx := l.CreateStaticSym(name)
if l.Syms[symIdx] != nil {
panic("can't build if sym.Symbol already present")
}
sb := &SymbolBuilder{l: l, symIdx: symIdx}
sb.extSymPayload = l.getPayload(symIdx)
return sb
}
// MakeSymbolUpdater creates a symbol builder helper for an existing
// symbol 'symIdx'. If 'symIdx' is not an external symbol, then create
// a clone of it (copy name, properties, etc) fix things up so that
// the lookup tables and caches point to the new version, not the old
// version.
func (l *Loader) MakeSymbolUpdater(symIdx Sym) *SymbolBuilder {
if symIdx == 0 {
panic("can't update the null symbol")
}
if !l.IsExternal(symIdx) {
// Create a clone with the same name/version/kind etc.
l.cloneToExternal(symIdx)
}
// Now that we're doing phase 2 DWARF generation using the loader
// but before the wavefront has reached dodata(), we can't have this
// assertion here. Commented out for now.
if false {
if l.Syms[symIdx] != nil {
panic(fmt.Sprintf("can't build if sym.Symbol %q already present", l.RawSymName(symIdx)))
}
}
// Construct updater and return.
sb := &SymbolBuilder{l: l, symIdx: symIdx}
sb.extSymPayload = l.getPayload(symIdx)
return sb
}
// CreateSymForUpdate creates a symbol with given name and version,
// returns a CreateSymForUpdate for update. If the symbol already
// exists, it will update in-place.
func (l *Loader) CreateSymForUpdate(name string, version int) *SymbolBuilder {
return l.MakeSymbolUpdater(l.LookupOrCreateSym(name, version))
}
// Getters for properties of the symbol we're working on.
func (sb *SymbolBuilder) Sym() Sym { return sb.symIdx }
func (sb *SymbolBuilder) Name() string { return sb.name }
func (sb *SymbolBuilder) Version() int { return sb.ver }
func (sb *SymbolBuilder) Type() sym.SymKind { return sb.kind }
func (sb *SymbolBuilder) Size() int64 { return sb.size }
func (sb *SymbolBuilder) Data() []byte { return sb.data }
func (sb *SymbolBuilder) Value() int64 { return sb.l.SymValue(sb.symIdx) }
func (sb *SymbolBuilder) Align() int32 { return sb.l.SymAlign(sb.symIdx) }
func (sb *SymbolBuilder) Localentry() uint8 { return sb.l.SymLocalentry(sb.symIdx) }
func (sb *SymbolBuilder) OnList() bool { return sb.l.AttrOnList(sb.symIdx) }
func (sb *SymbolBuilder) External() bool { return sb.l.AttrExternal(sb.symIdx) }
func (sb *SymbolBuilder) Extname() string { return sb.l.SymExtname(sb.symIdx) }
func (sb *SymbolBuilder) CgoExportDynamic() bool { return sb.l.AttrCgoExportDynamic(sb.symIdx) }
func (sb *SymbolBuilder) Dynimplib() string { return sb.l.SymDynimplib(sb.symIdx) }
func (sb *SymbolBuilder) Dynimpvers() string { return sb.l.SymDynimpvers(sb.symIdx) }
func (sb *SymbolBuilder) SubSym() Sym { return sb.l.SubSym(sb.symIdx) }
func (sb *SymbolBuilder) GoType() Sym { return sb.l.SymGoType(sb.symIdx) }
func (sb *SymbolBuilder) VisibilityHidden() bool { return sb.l.AttrVisibilityHidden(sb.symIdx) }
// Setters for symbol properties.
func (sb *SymbolBuilder) SetType(kind sym.SymKind) { sb.kind = kind }
func (sb *SymbolBuilder) SetSize(size int64) { sb.size = size }
func (sb *SymbolBuilder) SetData(data []byte) { sb.data = data }
func (sb *SymbolBuilder) SetOnList(v bool) { sb.l.SetAttrOnList(sb.symIdx, v) }
func (sb *SymbolBuilder) SetExternal(v bool) { sb.l.SetAttrExternal(sb.symIdx, v) }
func (sb *SymbolBuilder) SetValue(v int64) { sb.l.SetSymValue(sb.symIdx, v) }
func (sb *SymbolBuilder) SetAlign(align int32) { sb.l.SetSymAlign(sb.symIdx, align) }
func (sb *SymbolBuilder) SetLocalentry(value uint8) { sb.l.SetSymLocalentry(sb.symIdx, value) }
func (sb *SymbolBuilder) SetExtname(value string) { sb.l.SetSymExtname(sb.symIdx, value) }
func (sb *SymbolBuilder) SetDynimplib(value string) { sb.l.SetSymDynimplib(sb.symIdx, value) }
func (sb *SymbolBuilder) SetDynimpvers(value string) { sb.l.SetSymDynimpvers(sb.symIdx, value) }
func (sb *SymbolBuilder) SetPlt(value int32) { sb.l.SetPlt(sb.symIdx, value) }
func (sb *SymbolBuilder) SetGot(value int32) { sb.l.SetGot(sb.symIdx, value) }
func (sb *SymbolBuilder) SetSpecial(value bool) { sb.l.SetAttrSpecial(sb.symIdx, value) }
func (sb *SymbolBuilder) SetVisibilityHidden(value bool) {
sb.l.SetAttrVisibilityHidden(sb.symIdx, value)
}
func (sb *SymbolBuilder) SetNotInSymbolTable(value bool) {
sb.l.SetAttrNotInSymbolTable(sb.symIdx, value)
}
func (sb *SymbolBuilder) AddBytes(data []byte) {
sb.setReachable()
if sb.kind == 0 {
sb.kind = sym.SDATA
}
sb.data = append(sb.data, data...)
sb.size = int64(len(sb.data))
}
func (sb *SymbolBuilder) Relocs() Relocs {
return sb.l.Relocs(sb.symIdx)
}
func (sb *SymbolBuilder) SetRelocs(rslice []Reloc) {
n := len(rslice)
if cap(sb.relocs) < n {
sb.relocs = make([]goobj2.Reloc2, n)
sb.reltypes = make([]objabi.RelocType, n)
} else {
sb.relocs = sb.relocs[:n]
sb.reltypes = sb.reltypes[:n]
}
for i := range rslice {
sb.SetReloc(i, rslice[i])
}
}
func (sb *SymbolBuilder) AddReloc(r Reloc) {
// Populate a goobj2.Reloc from external reloc record.
var b goobj2.Reloc2
b.Set(r.Off, r.Size, 0, r.Add, goobj2.SymRef{PkgIdx: 0, SymIdx: uint32(r.Sym)})
sb.relocs = append(sb.relocs, b)
sb.reltypes = append(sb.reltypes, r.Type)
}
// Update the j-th relocation in place.
func (sb *SymbolBuilder) SetReloc(j int, r Reloc) {
// Populate a goobj2.Reloc from external reloc record.
sb.relocs[j].Set(r.Off, r.Size, 0, r.Add, goobj2.SymRef{PkgIdx: 0, SymIdx: uint32(r.Sym)})
sb.reltypes[j] = r.Type
}
func (sb *SymbolBuilder) Reachable() bool {
return sb.l.AttrReachable(sb.symIdx)
}
func (sb *SymbolBuilder) SetReachable(v bool) {
sb.l.SetAttrReachable(sb.symIdx, v)
}
func (sb *SymbolBuilder) setReachable() {
sb.SetReachable(true)
}
func (sb *SymbolBuilder) ReadOnly() bool {
return sb.l.AttrReadOnly(sb.symIdx)
}
func (sb *SymbolBuilder) SetReadOnly(v bool) {
sb.l.SetAttrReadOnly(sb.symIdx, v)
}
func (sb *SymbolBuilder) DuplicateOK() bool {
return sb.l.AttrDuplicateOK(sb.symIdx)
}
func (sb *SymbolBuilder) SetDuplicateOK(v bool) {
sb.l.SetAttrDuplicateOK(sb.symIdx, v)
}
func (sb *SymbolBuilder) Outer() Sym {
return sb.l.OuterSym(sb.symIdx)
}
func (sb *SymbolBuilder) Sub() Sym {
return sb.l.SubSym(sb.symIdx)
}
func (sb *SymbolBuilder) SortSub() {
sb.l.SortSub(sb.symIdx)
}
func (sb *SymbolBuilder) PrependSub(sub Sym) {
sb.l.PrependSub(sb.symIdx, sub)
}
func (sb *SymbolBuilder) AddUint8(v uint8) int64 {
off := sb.size
if sb.kind == 0 {
sb.kind = sym.SDATA
}
sb.setReachable()
sb.size++
sb.data = append(sb.data, v)
return off
}
func (sb *SymbolBuilder) AddUintXX(arch *sys.Arch, v uint64, wid int) int64 {
off := sb.size
sb.setReachable()
sb.setUintXX(arch, off, v, int64(wid))
return off
}
func (sb *SymbolBuilder) setUintXX(arch *sys.Arch, off int64, v uint64, wid int64) int64 {
if sb.kind == 0 {
sb.kind = sym.SDATA
}
if sb.size < off+wid {
sb.size = off + wid
sb.Grow(sb.size)
}
switch wid {
case 1:
sb.data[off] = uint8(v)
case 2:
arch.ByteOrder.PutUint16(sb.data[off:], uint16(v))
case 4:
arch.ByteOrder.PutUint32(sb.data[off:], uint32(v))
case 8:
arch.ByteOrder.PutUint64(sb.data[off:], v)
}
return off + wid
}
func (sb *SymbolBuilder) AddUint16(arch *sys.Arch, v uint16) int64 {
return sb.AddUintXX(arch, uint64(v), 2)
}
func (sb *SymbolBuilder) AddUint32(arch *sys.Arch, v uint32) int64 {
return sb.AddUintXX(arch, uint64(v), 4)
}
func (sb *SymbolBuilder) AddUint64(arch *sys.Arch, v uint64) int64 {
return sb.AddUintXX(arch, v, 8)
}
func (sb *SymbolBuilder) AddUint(arch *sys.Arch, v uint64) int64 {
return sb.AddUintXX(arch, v, arch.PtrSize)
}
func (sb *SymbolBuilder) SetUint8(arch *sys.Arch, r int64, v uint8) int64 {
sb.setReachable()
return sb.setUintXX(arch, r, uint64(v), 1)
}
func (sb *SymbolBuilder) SetUint16(arch *sys.Arch, r int64, v uint16) int64 {
sb.setReachable()
return sb.setUintXX(arch, r, uint64(v), 2)
}
func (sb *SymbolBuilder) SetUint32(arch *sys.Arch, r int64, v uint32) int64 {
sb.setReachable()
return sb.setUintXX(arch, r, uint64(v), 4)
}
func (sb *SymbolBuilder) SetUint(arch *sys.Arch, r int64, v uint64) int64 {
sb.setReachable()
return sb.setUintXX(arch, r, v, int64(arch.PtrSize))
}
func (sb *SymbolBuilder) Addstring(str string) int64 {
sb.setReachable()
if sb.kind == 0 {
sb.kind = sym.SNOPTRDATA
}
r := sb.size
if sb.name == ".shstrtab" {
// FIXME: find a better mechanism for this
sb.l.elfsetstring(nil, str, int(r))
}
sb.data = append(sb.data, str...)
sb.data = append(sb.data, 0)
sb.size = int64(len(sb.data))
return r
}
func (sb *SymbolBuilder) addSymRef(tgt Sym, add int64, typ objabi.RelocType, rsize int) int64 {
if sb.kind == 0 {
sb.kind = sym.SDATA
}
i := sb.size
sb.size += int64(rsize)
sb.Grow(sb.size)
var r Reloc
r.Sym = tgt
r.Off = int32(i)
r.Size = uint8(rsize)
r.Type = typ
r.Add = add
sb.AddReloc(r)
return i + int64(r.Size)
}
// Add a symbol reference (relocation) with given type, addend, and size
// (the most generic form).
func (sb *SymbolBuilder) AddSymRef(arch *sys.Arch, tgt Sym, add int64, typ objabi.RelocType, rsize int) int64 {
sb.setReachable()
return sb.addSymRef(tgt, add, typ, rsize)
}
func (sb *SymbolBuilder) AddAddrPlus(arch *sys.Arch, tgt Sym, add int64) int64 {
sb.setReachable()
return sb.addSymRef(tgt, add, objabi.R_ADDR, arch.PtrSize)
}
func (sb *SymbolBuilder) AddAddrPlus4(arch *sys.Arch, tgt Sym, add int64) int64 {
sb.setReachable()
return sb.addSymRef(tgt, add, objabi.R_ADDR, 4)
}
func (sb *SymbolBuilder) AddAddr(arch *sys.Arch, tgt Sym) int64 {
return sb.AddAddrPlus(arch, tgt, 0)
}
func (sb *SymbolBuilder) AddPCRelPlus(arch *sys.Arch, tgt Sym, add int64) int64 {
sb.setReachable()
return sb.addSymRef(tgt, add, objabi.R_PCREL, 4)
}
func (sb *SymbolBuilder) AddCURelativeAddrPlus(arch *sys.Arch, tgt Sym, add int64) int64 {
sb.setReachable()
return sb.addSymRef(tgt, add, objabi.R_ADDRCUOFF, arch.PtrSize)
}
func (sb *SymbolBuilder) AddSize(arch *sys.Arch, tgt Sym) int64 {
sb.setReachable()
return sb.addSymRef(tgt, 0, objabi.R_SIZE, arch.PtrSize)
}
|
