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Diffstat (limited to 'src/cmd/link/internal/loader/symbolbuilder.go')
| -rw-r--r-- | src/cmd/link/internal/loader/symbolbuilder.go | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/src/cmd/link/internal/loader/symbolbuilder.go b/src/cmd/link/internal/loader/symbolbuilder.go new file mode 100644 index 0000000000..0ce5c6bde8 --- /dev/null +++ b/src/cmd/link/internal/loader/symbolbuilder.go @@ -0,0 +1,349 @@ +// 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) +} |