package loader
import (
+ "cmd/internal/goobj"
"cmd/internal/objabi"
"cmd/internal/sys"
"cmd/link/internal/sym"
- "fmt"
+ "sort"
)
// SymbolBuilder is a helper designed to help with the construction
// 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.CreateExtSym(name)
- if l.Syms[symIdx] != nil {
- panic("can't build if sym.Symbol already present")
- }
+ symIdx := l.CreateStaticSym(name)
sb := &SymbolBuilder{l: l, symIdx: symIdx}
sb.extSymPayload = l.getPayload(symIdx)
return sb
// 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. Returns a SymbolBuilder and a Sym (which may be different
-// from the original if we had to clone).
-func (l *Loader) MakeSymbolUpdater(symIdx Sym) (*SymbolBuilder, Sym) {
+// version.
+func (l *Loader) MakeSymbolUpdater(symIdx Sym) *SymbolBuilder {
if symIdx == 0 {
panic("can't update the null symbol")
}
// Create a clone with the same name/version/kind etc.
l.cloneToExternal(symIdx)
}
- 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, 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 {
+ s := l.LookupOrCreateSym(name, version)
+ l.SetAttrReachable(s, true)
+ return l.MakeSymbolUpdater(s)
}
// Getters for properties of the symbol we're working on.
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) }
+func (sb *SymbolBuilder) Sect() *sym.Section { return sb.l.SymSect(sb.symIdx) }
// Setters for symbol properties.
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) SetLocal(value bool) { sb.l.SetAttrLocal(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) SetSect(sect *sym.Section) { sb.l.SetSymSect(sb.symIdx, sect) }
func (sb *SymbolBuilder) AddBytes(data []byte) {
- sb.setReachable()
if sb.kind == 0 {
sb.kind = sym.SDATA
}
sb.size = int64(len(sb.data))
}
-func (sb *SymbolBuilder) Relocs() []Reloc {
- return sb.relocs
+func (sb *SymbolBuilder) Relocs() Relocs {
+ return sb.l.Relocs(sb.symIdx)
}
-func (sb *SymbolBuilder) SetRelocs(rslice []Reloc) {
- sb.relocs = rslice
+// ResetRelocs removes all relocations on this symbol.
+func (sb *SymbolBuilder) ResetRelocs() {
+ sb.relocs = sb.relocs[:0]
}
-func (sb *SymbolBuilder) AddReloc(r Reloc) {
- sb.relocs = append(sb.relocs, r)
+// SetRelocType sets the type of the 'i'-th relocation on this sym to 't'
+func (sb *SymbolBuilder) SetRelocType(i int, t objabi.RelocType) {
+ sb.relocs[i].SetType(uint16(t))
+}
+
+// SetRelocSym sets the target sym of the 'i'-th relocation on this sym to 's'
+func (sb *SymbolBuilder) SetRelocSym(i int, tgt Sym) {
+ sb.relocs[i].SetSym(goobj.SymRef{PkgIdx: 0, SymIdx: uint32(tgt)})
+}
+
+// SetRelocAdd sets the addend of the 'i'-th relocation on this sym to 'a'
+func (sb *SymbolBuilder) SetRelocAdd(i int, a int64) {
+ sb.relocs[i].SetAdd(a)
+}
+
+// Add n relocations, return a handle to the relocations.
+func (sb *SymbolBuilder) AddRelocs(n int) Relocs {
+ sb.relocs = append(sb.relocs, make([]goobj.Reloc, n)...)
+ return sb.l.Relocs(sb.symIdx)
+}
+
+// Add a relocation with given type, return its handle and index
+// (to set other fields).
+func (sb *SymbolBuilder) AddRel(typ objabi.RelocType) (Reloc, int) {
+ j := len(sb.relocs)
+ sb.relocs = append(sb.relocs, goobj.Reloc{})
+ sb.relocs[j].SetType(uint16(typ))
+ relocs := sb.Relocs()
+ return relocs.At(j), j
+}
+
+// Sort relocations by offset.
+func (sb *SymbolBuilder) SortRelocs() {
+ sort.Sort((*relocsByOff)(sb.extSymPayload))
+}
+
+// Implement sort.Interface
+type relocsByOff extSymPayload
+
+func (p *relocsByOff) Len() int { return len(p.relocs) }
+func (p *relocsByOff) Less(i, j int) bool { return p.relocs[i].Off() < p.relocs[j].Off() }
+func (p *relocsByOff) Swap(i, j int) {
+ p.relocs[i], p.relocs[j] = p.relocs[j], p.relocs[i]
}
func (sb *SymbolBuilder) Reachable() bool {
return sb.l.AttrReachable(sb.symIdx)
}
-func (sb *SymbolBuilder) setReachable() {
- sb.l.SetAttrReachable(sb.symIdx, true)
+func (sb *SymbolBuilder) SetReachable(v bool) {
+ sb.l.SetAttrReachable(sb.symIdx, v)
}
func (sb *SymbolBuilder) ReadOnly() bool {
sb.l.SortSub(sb.symIdx)
}
-func (sb *SymbolBuilder) PrependSub(sub Sym) {
- sb.l.PrependSub(sb.symIdx, sub)
+func (sb *SymbolBuilder) AddInteriorSym(sub Sym) {
+ sb.l.AddInteriorSym(sb.symIdx, sub)
}
func (sb *SymbolBuilder) AddUint8(v uint8) int64 {
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) 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) SetUintptr(arch *sys.Arch, r int64, v uintptr) int64 {
+ return sb.setUintXX(arch, r, uint64(v), int64(arch.PtrSize))
+}
+
+func (sb *SymbolBuilder) SetAddrPlus(arch *sys.Arch, off int64, tgt Sym, add int64) int64 {
+ if sb.Type() == 0 {
+ sb.SetType(sym.SDATA)
+ }
+ if off+int64(arch.PtrSize) > sb.size {
+ sb.size = off + int64(arch.PtrSize)
+ sb.Grow(sb.size)
+ }
+ r, _ := sb.AddRel(objabi.R_ADDR)
+ r.SetSym(tgt)
+ r.SetOff(int32(off))
+ r.SetSiz(uint8(arch.PtrSize))
+ r.SetAdd(add)
+ return off + int64(r.Siz())
+}
+
+func (sb *SymbolBuilder) SetAddr(arch *sys.Arch, off int64, tgt Sym) int64 {
+ return sb.SetAddrPlus(arch, off, tgt, 0)
+}
+
+func (sb *SymbolBuilder) AddStringAt(off int64, str string) int64 {
+ strLen := int64(len(str))
+ if off+strLen > int64(len(sb.data)) {
+ panic("attempt to write past end of buffer")
+ }
+ copy(sb.data[off:off+strLen], str)
+ return off + strLen
+}
+
+// AddCStringAt adds str plus a null terminating byte.
+func (sb *SymbolBuilder) AddCStringAt(off int64, str string) int64 {
+ strLen := int64(len(str))
+ if off+strLen+1 > int64(len(sb.data)) {
+ panic("attempt to write past end of buffer")
+ }
+ copy(sb.data[off:off+strLen], str)
+ sb.data[off+strLen] = 0
+ return off + strLen + 1
+}
+
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) addRel() *Reloc {
- sb.relocs = append(sb.relocs, Reloc{})
- return &sb.relocs[len(sb.relocs)-1]
+func (sb *SymbolBuilder) SetBytesAt(off int64, b []byte) int64 {
+ datLen := int64(len(b))
+ if off+datLen > int64(len(sb.data)) {
+ panic("attempt to write past end of buffer")
+ }
+ copy(sb.data[off:off+datLen], b)
+ return off + datLen
}
-func (sb *SymbolBuilder) addAddrPlus(tgt Sym, add int64, typ objabi.RelocType, rsize int) int64 {
+func (sb *SymbolBuilder) addSymRef(tgt Sym, add int64, typ objabi.RelocType, rsize int) int64 {
if sb.kind == 0 {
sb.kind = sym.SDATA
}
sb.size += int64(rsize)
sb.Grow(sb.size)
- r := sb.addRel()
- r.Sym = tgt
- r.Off = int32(i)
- r.Size = uint8(rsize)
- r.Type = typ
- r.Add = add
+ r, _ := sb.AddRel(typ)
+ r.SetSym(tgt)
+ r.SetOff(int32(i))
+ r.SetSiz(uint8(rsize))
+ r.SetAdd(add)
- return i + int64(r.Size)
+ return i + int64(rsize)
+}
+
+// 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 {
+ return sb.addSymRef(tgt, add, typ, rsize)
}
func (sb *SymbolBuilder) AddAddrPlus(arch *sys.Arch, tgt Sym, add int64) int64 {
- sb.setReachable()
- return sb.addAddrPlus(tgt, add, objabi.R_ADDR, arch.PtrSize)
+ 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.addAddrPlus(tgt, add, objabi.R_ADDR, 4)
+ 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) AddPEImageRelativeAddrPlus(arch *sys.Arch, tgt Sym, add int64) int64 {
+ return sb.addSymRef(tgt, add, objabi.R_PEIMAGEOFF, 4)
+}
+
+func (sb *SymbolBuilder) AddPCRelPlus(arch *sys.Arch, tgt Sym, add int64) int64 {
+ 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.addAddrPlus(tgt, add, objabi.R_ADDRCUOFF, arch.PtrSize)
+ return sb.addSymRef(tgt, add, objabi.R_ADDRCUOFF, arch.PtrSize)
+}
+
+func (sb *SymbolBuilder) AddSize(arch *sys.Arch, tgt Sym) int64 {
+ return sb.addSymRef(tgt, 0, objabi.R_SIZE, arch.PtrSize)
+}
+
+// GenAddAddrPlusFunc returns a function to be called when capturing
+// a function symbol's address. In later stages of the link (when
+// address assignment is done) when doing internal linking and
+// targeting an executable, we can just emit the address of a function
+// directly instead of generating a relocation. Clients can call
+// this function (setting 'internalExec' based on build mode and target)
+// and then invoke the returned function in roughly the same way that
+// loader.*SymbolBuilder.AddAddrPlus would be used.
+func GenAddAddrPlusFunc(internalExec bool) func(s *SymbolBuilder, arch *sys.Arch, tgt Sym, add int64) int64 {
+ if internalExec {
+ return func(s *SymbolBuilder, arch *sys.Arch, tgt Sym, add int64) int64 {
+ if v := s.l.SymValue(tgt); v != 0 {
+ return s.AddUint(arch, uint64(v+add))
+ }
+ return s.AddAddrPlus(arch, tgt, add)
+ }
+ } else {
+ return (*SymbolBuilder).AddAddrPlus
+ }
+}
+
+func (sb *SymbolBuilder) MakeWritable() {
+ if sb.ReadOnly() {
+ sb.data = append([]byte(nil), sb.data...)
+ sb.l.SetAttrReadOnly(sb.symIdx, false)
+ }
+}
+
+func (sb *SymbolBuilder) AddUleb(v uint64) {
+ if v < 128 { // common case: 1 byte
+ sb.AddUint8(uint8(v))
+ return
+ }
+ for {
+ c := uint8(v & 0x7f)
+ v >>= 7
+ if v != 0 {
+ c |= 0x80
+ }
+ sb.AddUint8(c)
+ if c&0x80 == 0 {
+ break
+ }
+ }
}