[dev.link] cmd/link: store external relocations in Reloc2 format
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>
diff --git a/src/cmd/internal/goobj2/objfile.go b/src/cmd/internal/goobj2/objfile.go
index 2f275f3..c0d47b4 100644
--- a/src/cmd/internal/goobj2/objfile.go
+++ b/src/cmd/internal/goobj2/objfile.go
@@ -321,13 +321,21 @@
return SymRef{binary.LittleEndian.Uint32(r[14:]), binary.LittleEndian.Uint32(r[18:])}
}
+func (r *Reloc2) SetOff(x int32) { binary.LittleEndian.PutUint32(r[:], uint32(x)) }
+func (r *Reloc2) SetSiz(x uint8) { r[4] = x }
+func (r *Reloc2) SetType(x uint8) { r[5] = x }
+func (r *Reloc2) SetAdd(x int64) { binary.LittleEndian.PutUint64(r[6:], uint64(x)) }
+func (r *Reloc2) SetSym(x SymRef) {
+ binary.LittleEndian.PutUint32(r[14:], x.PkgIdx)
+ binary.LittleEndian.PutUint32(r[18:], x.SymIdx)
+}
+
func (r *Reloc2) Set(off int32, size uint8, typ uint8, add int64, sym SymRef) {
- binary.LittleEndian.PutUint32(r[:], uint32(off))
- r[4] = size
- r[5] = typ
- binary.LittleEndian.PutUint64(r[6:], uint64(add))
- binary.LittleEndian.PutUint32(r[14:], sym.PkgIdx)
- binary.LittleEndian.PutUint32(r[18:], sym.SymIdx)
+ r.SetOff(off)
+ r.SetSiz(size)
+ r.SetType(typ)
+ r.SetAdd(add)
+ r.SetSym(sym)
}
// Aux symbol info.
diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index f7d8d13..8ab67ef 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -602,7 +602,6 @@
func windynrelocsym(ctxt *Link, rel *loader.SymbolBuilder, s loader.Sym) {
var su *loader.SymbolBuilder
- var rslice []loader.Reloc
relocs := ctxt.loader.Relocs(s)
for ri := 0; ri < relocs.Count; ri++ {
r := relocs.At2(ri)
@@ -627,11 +626,9 @@
if su == nil {
su = ctxt.loader.MakeSymbolUpdater(s)
- rslice = su.Relocs()
}
- r := &rslice[ri]
- r.Sym = rel.Sym()
- r.Add = int64(tplt)
+ r.SetSym(rel.Sym())
+ r.SetAdd(int64(tplt))
// jmp *addr
switch ctxt.Arch.Family {
@@ -654,11 +651,9 @@
} else if tplt >= 0 {
if su == nil {
su = ctxt.loader.MakeSymbolUpdater(s)
- rslice = su.Relocs()
}
- r := &rslice[ri]
- r.Sym = rel.Sym()
- r.Add = int64(tplt)
+ r.SetSym(rel.Sym())
+ r.SetAdd(int64(tplt))
}
}
}
diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go
index 9f67a15..41dfa4f 100644
--- a/src/cmd/link/internal/ld/dwarf.go
+++ b/src/cmd/link/internal/ld/dwarf.go
@@ -132,16 +132,9 @@
switch size {
default:
c.linkctxt.Errorf(ds, "invalid size %d in adddwarfref\n", size)
- fallthrough
- case c.arch.PtrSize:
- dsu.AddAddrPlus(c.arch, tds, 0)
- case 4:
- dsu.AddAddrPlus4(c.arch, tds, 0)
+ case c.arch.PtrSize, 4:
}
- rsl := dsu.Relocs()
- r := &rsl[len(rsl)-1]
- r.Type = objabi.R_ADDROFF
- r.Add = ofs
+ dsu.AddSymRef(c.arch, tds, ofs, objabi.R_ADDROFF, size)
}
func (c dwctxt2) AddDWARFAddrSectionOffset(s dwarf.Sym, t interface{}, ofs int64) {
@@ -149,14 +142,15 @@
if isDwarf64(c.linkctxt) {
size = 8
}
-
- c.AddSectionOffset(s, size, t, ofs)
-
ds := loader.Sym(s.(dwSym))
dsu := c.ldr.MakeSymbolUpdater(ds)
- rsl := dsu.Relocs()
- r := &rsl[len(rsl)-1]
- r.Type = objabi.R_DWARFSECREF
+ tds := loader.Sym(t.(dwSym))
+ switch size {
+ default:
+ c.linkctxt.Errorf(ds, "invalid size %d in adddwarfref\n", size)
+ case c.arch.PtrSize, 4:
+ }
+ dsu.AddSymRef(c.arch, tds, ofs, objabi.R_DWARFSECREF, size)
}
func (c dwctxt2) Logf(format string, args ...interface{}) {
@@ -345,15 +339,9 @@
switch size {
default:
d.linkctxt.Errorf(sb.Sym(), "invalid size %d in adddwarfref\n", size)
- fallthrough
- case d.arch.PtrSize:
- result = sb.AddAddrPlus(d.arch, t, 0)
- case 4:
- result = sb.AddAddrPlus4(d.arch, t, 0)
+ case d.arch.PtrSize, 4:
}
- rsl := sb.Relocs()
- r := &rsl[len(rsl)-1]
- r.Type = objabi.R_DWARFSECREF
+ result = sb.AddSymRef(d.arch, t, 0, objabi.R_DWARFSECREF, size)
return result
}
diff --git a/src/cmd/link/internal/loader/loader.go b/src/cmd/link/internal/loader/loader.go
index f012648..9b71db6 100644
--- a/src/cmd/link/internal/loader/loader.go
+++ b/src/cmd/link/internal/loader/loader.go
@@ -68,6 +68,14 @@
func (rel Reloc2) Type() objabi.RelocType { return objabi.RelocType(rel.Reloc2.Type()) + rel.typ }
func (rel Reloc2) Sym() Sym { return rel.l.resolve(rel.r, rel.Reloc2.Sym()) }
+func (rel Reloc2) SetSym(s Sym) { rel.Reloc2.SetSym(goobj2.SymRef{PkgIdx: 0, SymIdx: uint32(s)}) }
+
+func (rel Reloc2) SetType(t objabi.RelocType) {
+ if t != objabi.RelocType(uint8(t)) {
+ panic("SetType: type doesn't fit into Reloc2")
+ }
+ rel.Reloc2.SetType(uint8(t))
+}
// Aux2 holds a "handle" to access an aux symbol record from an
// object file.
@@ -269,14 +277,15 @@
// extSymPayload holds the payload (data + relocations) for linker-synthesized
// external symbols (note that symbol value is stored in a separate slice).
type extSymPayload struct {
- name string // TODO: would this be better as offset into str table?
- size int64
- ver int
- kind sym.SymKind
- objidx uint32 // index of original object if sym made by cloneToExternal
- gotype Sym // Gotype (0 if not present)
- relocs []Reloc
- data []byte
+ name string // TODO: would this be better as offset into str table?
+ size int64
+ ver int
+ kind sym.SymKind
+ objidx uint32 // index of original object if sym made by cloneToExternal
+ gotype Sym // Gotype (0 if not present)
+ relocs []goobj2.Reloc2
+ reltypes []objabi.RelocType // relocation types
+ data []byte
}
const (
@@ -1468,91 +1477,15 @@
}
}
-// At method returns the j-th reloc for a global symbol.
-func (relocs *Relocs) At(j int) Reloc {
- if relocs.l.isExtReader(relocs.r) {
- pp := relocs.l.payloads[relocs.li]
- return pp.relocs[j]
- }
- rel := goobj2.Reloc{}
- rel.Read(relocs.r.Reader, relocs.r.RelocOff(relocs.li, j))
- target := relocs.l.resolve(relocs.r, rel.Sym)
- return Reloc{
- Off: rel.Off,
- Size: rel.Siz,
- Type: objabi.RelocType(rel.Type),
- Add: rel.Add,
- Sym: target,
- }
-}
-
+// At2 returns the j-th reloc for a global symbol.
func (relocs *Relocs) At2(j int) Reloc2 {
if relocs.l.isExtReader(relocs.r) {
pp := relocs.l.payloads[relocs.li]
- r := pp.relocs[j]
- // XXX populate a goobj2.Reloc from external reloc record.
- // Ugly. Maybe we just want to use this format to store the
- // reloc record in the first place?
- // Also there is more speedup if we could remove the
- // conditional here.
- var b goobj2.Reloc2
- b.Set(r.Off, r.Size, 0, r.Add, goobj2.SymRef{PkgIdx: 0, SymIdx: uint32(r.Sym)})
- return Reloc2{&b, relocs.r, relocs.l, r.Type}
+ return Reloc2{&relocs.rs[j], relocs.r, relocs.l, pp.reltypes[j]}
}
return Reloc2{&relocs.rs[j], relocs.r, relocs.l, 0}
}
-// ReadAll method reads all relocations for a symbol into the
-// specified slice. If the slice capacity is not large enough, a new
-// larger slice will be allocated. Final slice is returned.
-func (relocs *Relocs) ReadAll(dst []Reloc) []Reloc {
- return relocs.readAll(dst, false)
-}
-
-// ReadSyms method reads all relocation target symbols and reloc types
-// for a symbol into the specified slice. It is like ReadAll but only
-// fill in the Sym and Type fields.
-func (relocs *Relocs) ReadSyms(dst []Reloc) []Reloc {
- return relocs.readAll(dst, true)
-}
-
-func (relocs *Relocs) readAll(dst []Reloc, onlySymType bool) []Reloc {
- if relocs.Count == 0 {
- return dst[:0]
- }
-
- if cap(dst) < relocs.Count {
- dst = make([]Reloc, relocs.Count)
- }
- dst = dst[:0]
-
- if relocs.l.isExtReader(relocs.r) {
- pp := relocs.l.payloads[relocs.li]
- dst = append(dst, pp.relocs...)
- return dst
- }
-
- off := relocs.r.RelocOff(relocs.li, 0)
- rel := goobj2.Reloc{}
- for i := 0; i < relocs.Count; i++ {
- if onlySymType {
- rel.ReadSymType(relocs.r.Reader, off)
- } else {
- rel.Read(relocs.r.Reader, off)
- }
- off += uint32(rel.Size())
- target := relocs.l.resolve(relocs.r, rel.Sym)
- dst = append(dst, Reloc{
- Off: rel.Off,
- Size: rel.Siz,
- Type: objabi.RelocType(rel.Type),
- Add: rel.Add,
- Sym: target,
- })
- }
- return dst
-}
-
// Relocs returns a Relocs object for the given global sym.
func (l *Loader) Relocs(i Sym) Relocs {
r, li := l.toLocal(i)
@@ -1569,6 +1502,7 @@
if l.isExtReader(r) {
pp := l.payloads[li]
n = len(pp.relocs)
+ rs = pp.relocs
} else {
rs = r.Relocs2(li)
n = len(rs)
@@ -2237,7 +2171,15 @@
// Copy relocations
relocs := l.Relocs(symIdx)
- pp.relocs = relocs.ReadAll(nil)
+ pp.relocs = make([]goobj2.Reloc2, relocs.Count)
+ pp.reltypes = make([]objabi.RelocType, relocs.Count)
+ for i := range pp.relocs {
+ // Copy the relocs slice.
+ // Convert local reference to global reference.
+ rel := relocs.At2(i)
+ pp.relocs[i].Set(rel.Off(), rel.Siz(), 0, rel.Add(), goobj2.SymRef{PkgIdx: 0, SymIdx: uint32(rel.Sym())})
+ pp.reltypes[i] = rel.Type()
+ }
// Copy data
pp.data = r.Data(li)
@@ -2634,7 +2576,7 @@
}
if rs != 0 && l.Syms[rs] != nil && l.Syms[rs].Type == sym.SABIALIAS {
rsrelocs := l.Relocs(rs)
- rs = rsrelocs.At(0).Sym
+ rs = rsrelocs.At2(0).Sym()
}
if strict && rs != 0 && l.Syms[rs] == nil && rt != objabi.R_USETYPE {
panic("nil reloc target in convertRelocations")
@@ -2659,14 +2601,13 @@
// 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)
+ r := relocs.At2(ri)
+ rs := r.Sym()
+ if rs != 0 && l.SymType(rs) == sym.SXREF && l.RawSymName(rs) != ".got" {
+ result = append(result, rs)
if limit != -1 && len(result) >= limit {
break
}
diff --git a/src/cmd/link/internal/loader/loader_test.go b/src/cmd/link/internal/loader/loader_test.go
index b384c75..8c9f7cf 100644
--- a/src/cmd/link/internal/loader/loader_test.go
+++ b/src/cmd/link/internal/loader/loader_test.go
@@ -173,14 +173,9 @@
for k, sb := range []*SymbolBuilder{sb1, sb2} {
rsl := sb.Relocs()
exp := expRel[k]
- if !sameRelocSlice(rsl, exp) {
+ if !sameRelocSlice(&rsl, exp) {
t.Errorf("expected relocs %v, got %v", exp, rsl)
}
- relocs := ldr.Relocs(sb.Sym())
- r0 := relocs.At(0)
- if r0 != exp[0] {
- t.Errorf("expected reloc %v, got %v", exp[0], r0)
- }
}
// ... then data.
@@ -213,12 +208,18 @@
}
}
-func sameRelocSlice(s1 []Reloc, s2 []Reloc) bool {
- if len(s1) != len(s2) {
+func sameRelocSlice(s1 *Relocs, s2 []Reloc) bool {
+ if s1.Count != len(s2) {
return false
}
- for i := 0; i < len(s1); i++ {
- if s1[i] != s2[i] {
+ for i := 0; i < s1.Count; i++ {
+ r1 := s1.At2(i)
+ r2 := &s2[i]
+ if r1.Sym() != r2.Sym ||
+ r1.Type() != r2.Type ||
+ r1.Off() != r2.Off ||
+ r1.Add() != r2.Add ||
+ r1.Siz() != r2.Size {
return false
}
}
@@ -342,10 +343,9 @@
t.Fatalf("testing Loader.%s: sym updated should be reachable", tp.which)
}
relocs := ldr.Relocs(mi)
- rsl := relocs.ReadAll(nil)
- if !sameRelocSlice(rsl, tp.expRel) {
+ if !sameRelocSlice(&relocs, tp.expRel) {
t.Fatalf("testing Loader.%s: got relocslice %+v wanted %+v",
- tp.which, rsl, tp.expRel)
+ tp.which, relocs, tp.expRel)
}
pmi = mi
}
diff --git a/src/cmd/link/internal/loader/symbolbuilder.go b/src/cmd/link/internal/loader/symbolbuilder.go
index c26646c..0ce5c6b 100644
--- a/src/cmd/link/internal/loader/symbolbuilder.go
+++ b/src/cmd/link/internal/loader/symbolbuilder.go
@@ -5,6 +5,7 @@
package loader
import (
+ "cmd/internal/goobj2"
"cmd/internal/objabi"
"cmd/internal/sys"
"cmd/link/internal/sym"
@@ -121,23 +122,37 @@
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
-}
-
-func (sb *SymbolBuilder) WriteRelocs(rslice []Reloc) {
- if len(sb.relocs) != len(rslice) {
- panic("src/dest length mismatch")
+ 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]
}
- copy(sb.relocs, rslice)
+ for i := range rslice {
+ sb.SetReloc(i, rslice[i])
+ }
}
func (sb *SymbolBuilder) AddReloc(r Reloc) {
- sb.relocs = append(sb.relocs, r)
+ // 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 {
@@ -277,11 +292,6 @@
return r
}
-func (sb *SymbolBuilder) addRel() *Reloc {
- sb.relocs = append(sb.relocs, Reloc{})
- return &sb.relocs[len(sb.relocs)-1]
-}
-
func (sb *SymbolBuilder) addSymRef(tgt Sym, add int64, typ objabi.RelocType, rsize int) int64 {
if sb.kind == 0 {
sb.kind = sym.SDATA
@@ -291,12 +301,13 @@
sb.size += int64(rsize)
sb.Grow(sb.size)
- r := sb.addRel()
+ 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)
}
