mirror of
https://github.com/golang/go.git
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6e3bde5f30
Store external relocations in (almost) the same format as the Go objects, so we can handle them more uniformly. There is a small speedup: (linking cmd/compile) Deadcode 67.8ms ± 3% 61.1ms ± 3% -9.94% (p=0.008 n=5+5) Dostkcheck 41.2ms ± 2% 38.8ms ± 3% -5.99% (p=0.008 n=5+5) Change-Id: I8616e10b26235904201d6c9465f5ae32a49c9949 Reviewed-on: https://go-review.googlesource.com/c/go/+/226365 Run-TryBot: Cherry Zhang <cherryyz@google.com> Reviewed-by: Than McIntosh <thanm@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
350 lines
11 KiB
Go
350 lines
11 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package loader
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import (
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"cmd/internal/goobj2"
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"cmd/internal/objabi"
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"cmd/internal/sys"
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"cmd/link/internal/sym"
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"fmt"
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)
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// SymbolBuilder is a helper designed to help with the construction
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// of new symbol contents.
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type SymbolBuilder struct {
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*extSymPayload // points to payload being updated
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symIdx Sym // index of symbol being updated/constructed
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l *Loader // loader
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}
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// MakeSymbolBuilder creates a symbol builder for use in constructing
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// an entirely new symbol.
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func (l *Loader) MakeSymbolBuilder(name string) *SymbolBuilder {
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// for now assume that any new sym is intended to be static
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symIdx := l.CreateStaticSym(name)
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if l.Syms[symIdx] != nil {
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panic("can't build if sym.Symbol already present")
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}
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sb := &SymbolBuilder{l: l, symIdx: symIdx}
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sb.extSymPayload = l.getPayload(symIdx)
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return sb
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}
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// MakeSymbolUpdater creates a symbol builder helper for an existing
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// symbol 'symIdx'. If 'symIdx' is not an external symbol, then create
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// a clone of it (copy name, properties, etc) fix things up so that
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// the lookup tables and caches point to the new version, not the old
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// version.
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func (l *Loader) MakeSymbolUpdater(symIdx Sym) *SymbolBuilder {
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if symIdx == 0 {
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panic("can't update the null symbol")
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}
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if !l.IsExternal(symIdx) {
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// Create a clone with the same name/version/kind etc.
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l.cloneToExternal(symIdx)
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}
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// Now that we're doing phase 2 DWARF generation using the loader
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// but before the wavefront has reached dodata(), we can't have this
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// assertion here. Commented out for now.
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if false {
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if l.Syms[symIdx] != nil {
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panic(fmt.Sprintf("can't build if sym.Symbol %q already present", l.RawSymName(symIdx)))
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}
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}
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// Construct updater and return.
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sb := &SymbolBuilder{l: l, symIdx: symIdx}
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sb.extSymPayload = l.getPayload(symIdx)
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return sb
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}
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// CreateSymForUpdate creates a symbol with given name and version,
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// returns a CreateSymForUpdate for update. If the symbol already
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// exists, it will update in-place.
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func (l *Loader) CreateSymForUpdate(name string, version int) *SymbolBuilder {
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return l.MakeSymbolUpdater(l.LookupOrCreateSym(name, version))
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}
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// Getters for properties of the symbol we're working on.
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func (sb *SymbolBuilder) Sym() Sym { return sb.symIdx }
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func (sb *SymbolBuilder) Name() string { return sb.name }
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func (sb *SymbolBuilder) Version() int { return sb.ver }
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func (sb *SymbolBuilder) Type() sym.SymKind { return sb.kind }
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func (sb *SymbolBuilder) Size() int64 { return sb.size }
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func (sb *SymbolBuilder) Data() []byte { return sb.data }
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func (sb *SymbolBuilder) Value() int64 { return sb.l.SymValue(sb.symIdx) }
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func (sb *SymbolBuilder) Align() int32 { return sb.l.SymAlign(sb.symIdx) }
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func (sb *SymbolBuilder) Localentry() uint8 { return sb.l.SymLocalentry(sb.symIdx) }
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func (sb *SymbolBuilder) OnList() bool { return sb.l.AttrOnList(sb.symIdx) }
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func (sb *SymbolBuilder) External() bool { return sb.l.AttrExternal(sb.symIdx) }
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func (sb *SymbolBuilder) Extname() string { return sb.l.SymExtname(sb.symIdx) }
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func (sb *SymbolBuilder) CgoExportDynamic() bool { return sb.l.AttrCgoExportDynamic(sb.symIdx) }
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func (sb *SymbolBuilder) Dynimplib() string { return sb.l.SymDynimplib(sb.symIdx) }
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func (sb *SymbolBuilder) Dynimpvers() string { return sb.l.SymDynimpvers(sb.symIdx) }
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func (sb *SymbolBuilder) SubSym() Sym { return sb.l.SubSym(sb.symIdx) }
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func (sb *SymbolBuilder) GoType() Sym { return sb.l.SymGoType(sb.symIdx) }
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func (sb *SymbolBuilder) VisibilityHidden() bool { return sb.l.AttrVisibilityHidden(sb.symIdx) }
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// Setters for symbol properties.
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func (sb *SymbolBuilder) SetType(kind sym.SymKind) { sb.kind = kind }
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func (sb *SymbolBuilder) SetSize(size int64) { sb.size = size }
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func (sb *SymbolBuilder) SetData(data []byte) { sb.data = data }
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func (sb *SymbolBuilder) SetOnList(v bool) { sb.l.SetAttrOnList(sb.symIdx, v) }
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func (sb *SymbolBuilder) SetExternal(v bool) { sb.l.SetAttrExternal(sb.symIdx, v) }
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func (sb *SymbolBuilder) SetValue(v int64) { sb.l.SetSymValue(sb.symIdx, v) }
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func (sb *SymbolBuilder) SetAlign(align int32) { sb.l.SetSymAlign(sb.symIdx, align) }
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func (sb *SymbolBuilder) SetLocalentry(value uint8) { sb.l.SetSymLocalentry(sb.symIdx, value) }
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func (sb *SymbolBuilder) SetExtname(value string) { sb.l.SetSymExtname(sb.symIdx, value) }
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func (sb *SymbolBuilder) SetDynimplib(value string) { sb.l.SetSymDynimplib(sb.symIdx, value) }
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func (sb *SymbolBuilder) SetDynimpvers(value string) { sb.l.SetSymDynimpvers(sb.symIdx, value) }
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func (sb *SymbolBuilder) SetPlt(value int32) { sb.l.SetPlt(sb.symIdx, value) }
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func (sb *SymbolBuilder) SetGot(value int32) { sb.l.SetGot(sb.symIdx, value) }
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func (sb *SymbolBuilder) SetSpecial(value bool) { sb.l.SetAttrSpecial(sb.symIdx, value) }
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func (sb *SymbolBuilder) SetVisibilityHidden(value bool) {
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sb.l.SetAttrVisibilityHidden(sb.symIdx, value)
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}
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func (sb *SymbolBuilder) SetNotInSymbolTable(value bool) {
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sb.l.SetAttrNotInSymbolTable(sb.symIdx, value)
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}
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func (sb *SymbolBuilder) AddBytes(data []byte) {
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sb.setReachable()
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if sb.kind == 0 {
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sb.kind = sym.SDATA
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}
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sb.data = append(sb.data, data...)
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sb.size = int64(len(sb.data))
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}
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func (sb *SymbolBuilder) Relocs() Relocs {
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return sb.l.Relocs(sb.symIdx)
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}
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func (sb *SymbolBuilder) SetRelocs(rslice []Reloc) {
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n := len(rslice)
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if cap(sb.relocs) < n {
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sb.relocs = make([]goobj2.Reloc2, n)
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sb.reltypes = make([]objabi.RelocType, n)
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} else {
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sb.relocs = sb.relocs[:n]
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sb.reltypes = sb.reltypes[:n]
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}
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for i := range rslice {
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sb.SetReloc(i, rslice[i])
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}
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}
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func (sb *SymbolBuilder) AddReloc(r Reloc) {
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// Populate a goobj2.Reloc from external reloc record.
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var b goobj2.Reloc2
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b.Set(r.Off, r.Size, 0, r.Add, goobj2.SymRef{PkgIdx: 0, SymIdx: uint32(r.Sym)})
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sb.relocs = append(sb.relocs, b)
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sb.reltypes = append(sb.reltypes, r.Type)
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}
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// Update the j-th relocation in place.
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func (sb *SymbolBuilder) SetReloc(j int, r Reloc) {
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// Populate a goobj2.Reloc from external reloc record.
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sb.relocs[j].Set(r.Off, r.Size, 0, r.Add, goobj2.SymRef{PkgIdx: 0, SymIdx: uint32(r.Sym)})
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sb.reltypes[j] = r.Type
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}
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func (sb *SymbolBuilder) Reachable() bool {
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return sb.l.AttrReachable(sb.symIdx)
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}
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func (sb *SymbolBuilder) SetReachable(v bool) {
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sb.l.SetAttrReachable(sb.symIdx, v)
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}
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func (sb *SymbolBuilder) setReachable() {
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sb.SetReachable(true)
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}
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func (sb *SymbolBuilder) ReadOnly() bool {
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return sb.l.AttrReadOnly(sb.symIdx)
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}
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func (sb *SymbolBuilder) SetReadOnly(v bool) {
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sb.l.SetAttrReadOnly(sb.symIdx, v)
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}
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func (sb *SymbolBuilder) DuplicateOK() bool {
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return sb.l.AttrDuplicateOK(sb.symIdx)
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}
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func (sb *SymbolBuilder) SetDuplicateOK(v bool) {
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sb.l.SetAttrDuplicateOK(sb.symIdx, v)
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}
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func (sb *SymbolBuilder) Outer() Sym {
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return sb.l.OuterSym(sb.symIdx)
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}
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func (sb *SymbolBuilder) Sub() Sym {
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return sb.l.SubSym(sb.symIdx)
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}
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func (sb *SymbolBuilder) SortSub() {
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sb.l.SortSub(sb.symIdx)
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}
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func (sb *SymbolBuilder) PrependSub(sub Sym) {
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sb.l.PrependSub(sb.symIdx, sub)
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}
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func (sb *SymbolBuilder) AddUint8(v uint8) int64 {
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off := sb.size
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if sb.kind == 0 {
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sb.kind = sym.SDATA
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}
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sb.setReachable()
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sb.size++
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sb.data = append(sb.data, v)
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return off
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}
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func (sb *SymbolBuilder) AddUintXX(arch *sys.Arch, v uint64, wid int) int64 {
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off := sb.size
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sb.setReachable()
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sb.setUintXX(arch, off, v, int64(wid))
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return off
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}
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func (sb *SymbolBuilder) setUintXX(arch *sys.Arch, off int64, v uint64, wid int64) int64 {
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if sb.kind == 0 {
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sb.kind = sym.SDATA
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}
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if sb.size < off+wid {
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sb.size = off + wid
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sb.Grow(sb.size)
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}
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switch wid {
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case 1:
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sb.data[off] = uint8(v)
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case 2:
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arch.ByteOrder.PutUint16(sb.data[off:], uint16(v))
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case 4:
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arch.ByteOrder.PutUint32(sb.data[off:], uint32(v))
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case 8:
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arch.ByteOrder.PutUint64(sb.data[off:], v)
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}
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return off + wid
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}
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func (sb *SymbolBuilder) AddUint16(arch *sys.Arch, v uint16) int64 {
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return sb.AddUintXX(arch, uint64(v), 2)
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}
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func (sb *SymbolBuilder) AddUint32(arch *sys.Arch, v uint32) int64 {
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return sb.AddUintXX(arch, uint64(v), 4)
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}
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func (sb *SymbolBuilder) AddUint64(arch *sys.Arch, v uint64) int64 {
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return sb.AddUintXX(arch, v, 8)
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}
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func (sb *SymbolBuilder) AddUint(arch *sys.Arch, v uint64) int64 {
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return sb.AddUintXX(arch, v, arch.PtrSize)
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}
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func (sb *SymbolBuilder) SetUint8(arch *sys.Arch, r int64, v uint8) int64 {
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sb.setReachable()
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return sb.setUintXX(arch, r, uint64(v), 1)
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}
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func (sb *SymbolBuilder) SetUint16(arch *sys.Arch, r int64, v uint16) int64 {
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sb.setReachable()
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return sb.setUintXX(arch, r, uint64(v), 2)
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}
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func (sb *SymbolBuilder) SetUint32(arch *sys.Arch, r int64, v uint32) int64 {
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sb.setReachable()
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return sb.setUintXX(arch, r, uint64(v), 4)
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}
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func (sb *SymbolBuilder) SetUint(arch *sys.Arch, r int64, v uint64) int64 {
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sb.setReachable()
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return sb.setUintXX(arch, r, v, int64(arch.PtrSize))
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}
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func (sb *SymbolBuilder) Addstring(str string) int64 {
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sb.setReachable()
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if sb.kind == 0 {
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sb.kind = sym.SNOPTRDATA
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}
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r := sb.size
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if sb.name == ".shstrtab" {
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// FIXME: find a better mechanism for this
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sb.l.elfsetstring(nil, str, int(r))
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}
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sb.data = append(sb.data, str...)
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sb.data = append(sb.data, 0)
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sb.size = int64(len(sb.data))
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return r
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}
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func (sb *SymbolBuilder) addSymRef(tgt Sym, add int64, typ objabi.RelocType, rsize int) int64 {
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if sb.kind == 0 {
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sb.kind = sym.SDATA
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}
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i := sb.size
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sb.size += int64(rsize)
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sb.Grow(sb.size)
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var r Reloc
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r.Sym = tgt
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r.Off = int32(i)
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r.Size = uint8(rsize)
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r.Type = typ
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r.Add = add
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sb.AddReloc(r)
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return i + int64(r.Size)
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}
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// Add a symbol reference (relocation) with given type, addend, and size
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// (the most generic form).
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func (sb *SymbolBuilder) AddSymRef(arch *sys.Arch, tgt Sym, add int64, typ objabi.RelocType, rsize int) int64 {
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sb.setReachable()
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return sb.addSymRef(tgt, add, typ, rsize)
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}
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func (sb *SymbolBuilder) AddAddrPlus(arch *sys.Arch, tgt Sym, add int64) int64 {
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sb.setReachable()
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return sb.addSymRef(tgt, add, objabi.R_ADDR, arch.PtrSize)
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}
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func (sb *SymbolBuilder) AddAddrPlus4(arch *sys.Arch, tgt Sym, add int64) int64 {
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sb.setReachable()
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return sb.addSymRef(tgt, add, objabi.R_ADDR, 4)
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}
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func (sb *SymbolBuilder) AddAddr(arch *sys.Arch, tgt Sym) int64 {
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return sb.AddAddrPlus(arch, tgt, 0)
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}
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func (sb *SymbolBuilder) AddPCRelPlus(arch *sys.Arch, tgt Sym, add int64) int64 {
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sb.setReachable()
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return sb.addSymRef(tgt, add, objabi.R_PCREL, 4)
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}
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func (sb *SymbolBuilder) AddCURelativeAddrPlus(arch *sys.Arch, tgt Sym, add int64) int64 {
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sb.setReachable()
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return sb.addSymRef(tgt, add, objabi.R_ADDRCUOFF, arch.PtrSize)
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}
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func (sb *SymbolBuilder) AddSize(arch *sys.Arch, tgt Sym) int64 {
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sb.setReachable()
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return sb.addSymRef(tgt, 0, objabi.R_SIZE, arch.PtrSize)
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}
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