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[dev.link] cmd/link: simplify DWARF DIE symbol payload

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Get rid of of the linker's dwSym struct (which wraps a loader.Loader
and a loader.Sym) in favor of just loader.Sym. This requires some minor
tweaks to the cmd/internal/dwarf interfaces.

Change-Id: Id3ffd7c41b2433ea04417040368700334bb0e611
Reviewed-on: https://go-review.googlesource.com/c/go/+/220982
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
This commit is contained in:
Than McIntosh 2020-02-19 16:16:17 -05:00
parent 23c52de5fc
commit 48c79db07f
4 changed files with 70 additions and 73 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/cmd/internal/dwarf/dwarf.go
View File

@ -48,7 +48,7 @@ var logDwarf bool
// Sym represents a symbol.
type Sym interface {
Len() int64
Length(dwarfContext interface{}) int64
}
// A Var represents a local variable or a function parameter.
@ -1279,7 +1279,7 @@ func PutInlinedFunc(ctxt Context, s *FnState, callersym Sym, callIdx int) error
putattr(ctxt, s.Info, abbrev, DW_FORM_ref_addr, DW_CLS_REFERENCE, 0, callee)
if abbrev == DW_ABRV_INLINED_SUBROUTINE_RANGES {
putattr(ctxt, s.Info, abbrev, DW_FORM_sec_offset, DW_CLS_PTR, s.Ranges.Len(), s.Ranges)
putattr(ctxt, s.Info, abbrev, DW_FORM_sec_offset, DW_CLS_PTR, s.Ranges.Length(ctxt), s.Ranges)
s.PutRanges(ctxt, ic.Ranges)
} else {
st := ic.Ranges[0].Start
@ -1440,7 +1440,7 @@ func putscope(ctxt Context, s *FnState, scopes []Scope, curscope int32, fnabbrev
putattr(ctxt, s.Info, DW_ABRV_LEXICAL_BLOCK_SIMPLE, DW_FORM_addr, DW_CLS_ADDRESS, scope.Ranges[0].End, s.StartPC)
} else {
Uleb128put(ctxt, s.Info, DW_ABRV_LEXICAL_BLOCK_RANGES)
putattr(ctxt, s.Info, DW_ABRV_LEXICAL_BLOCK_RANGES, DW_FORM_sec_offset, DW_CLS_PTR, s.Ranges.Len(), s.Ranges)
putattr(ctxt, s.Info, DW_ABRV_LEXICAL_BLOCK_RANGES, DW_FORM_sec_offset, DW_CLS_PTR, s.Ranges.Length(ctxt), s.Ranges)
s.PutRanges(ctxt, scope.Ranges)
}
@ -1585,7 +1585,7 @@ func putvar(ctxt Context, s *FnState, v *Var, absfn Sym, fnabbrev, inlIndex int,
}
if abbrevUsesLoclist(abbrev) {
putattr(ctxt, s.Info, abbrev, DW_FORM_sec_offset, DW_CLS_PTR, s.Loc.Len(), s.Loc)
putattr(ctxt, s.Info, abbrev, DW_FORM_sec_offset, DW_CLS_PTR, s.Loc.Length(ctxt), s.Loc)
v.PutLocationList(s.Loc, s.StartPC)
} else {
loc := encbuf[:0]

2
src/cmd/internal/obj/objfile.go
View File

@ -216,7 +216,7 @@ func (ctxt *Link) dwarfSym(s *LSym) (dwarfInfoSym, dwarfLocSym, dwarfRangesSym,
return s.Func.dwarfInfoSym, s.Func.dwarfLocSym, s.Func.dwarfRangesSym, s.Func.dwarfAbsFnSym, s.Func.dwarfDebugLinesSym
}
func (s *LSym) Len() int64 {
func (s *LSym) Length(dwarfContext interface{}) int64 {
return s.Size
}

129
src/cmd/link/internal/ld/dwarf.go
View File

@ -70,60 +70,70 @@ func newdwctxt2(linkctxt *Link, forTypeGen bool) dwctxt2 {
return d
}
// dwSym wraps a loader.Sym; this type is meant to obey the interface
// rules for dwarf.Sym from the cmd/internal/dwarf package. DwDie and
// DwAttr objects contain references to symbols via this type.
type dwSym loader.Sym
func (s dwSym) Length(dwarfContext interface{}) int64 {
l := dwarfContext.(dwctxt2).ldr
return int64(len(l.Data(loader.Sym(s))))
}
func (c dwctxt2) PtrSize() int {
return c.arch.PtrSize
}
func (c dwctxt2) AddInt(s dwarf.Sym, size int, i int64) {
ds := s.(dwSym)
dsu := ds.l.MakeSymbolUpdater(ds.s)
ds := loader.Sym(s.(dwSym))
dsu := c.ldr.MakeSymbolUpdater(ds)
dsu.AddUintXX(c.arch, uint64(i), size)
}
func (c dwctxt2) AddBytes(s dwarf.Sym, b []byte) {
ds := s.(dwSym)
dsu := ds.l.MakeSymbolUpdater(ds.s)
ds := loader.Sym(s.(dwSym))
dsu := c.ldr.MakeSymbolUpdater(ds)
dsu.AddBytes(b)
}
func (c dwctxt2) AddString(s dwarf.Sym, v string) {
ds := s.(dwSym)
dsu := ds.l.MakeSymbolUpdater(ds.s)
ds := loader.Sym(s.(dwSym))
dsu := c.ldr.MakeSymbolUpdater(ds)
dsu.Addstring(v)
}
func (c dwctxt2) AddAddress(s dwarf.Sym, data interface{}, value int64) {
ds := s.(dwSym)
dsu := ds.l.MakeSymbolUpdater(ds.s)
ds := loader.Sym(s.(dwSym))
dsu := c.ldr.MakeSymbolUpdater(ds)
if value != 0 {
value -= dsu.Value()
}
tgtds := data.(dwSym)
dsu.AddAddrPlus(c.arch, tgtds.s, value)
tgtds := loader.Sym(data.(dwSym))
dsu.AddAddrPlus(c.arch, tgtds, value)
}
func (c dwctxt2) AddCURelativeAddress(s dwarf.Sym, data interface{}, value int64) {
ds := s.(dwSym)
dsu := ds.l.MakeSymbolUpdater(ds.s)
ds := loader.Sym(s.(dwSym))
dsu := c.ldr.MakeSymbolUpdater(ds)
if value != 0 {
value -= dsu.Value()
}
tgtds := data.(dwSym)
dsu.AddCURelativeAddrPlus(c.arch, tgtds.s, value)
tgtds := loader.Sym(data.(dwSym))
dsu.AddCURelativeAddrPlus(c.arch, tgtds, value)
}
func (c dwctxt2) AddSectionOffset(s dwarf.Sym, size int, t interface{}, ofs int64) {
ds := s.(dwSym)
dsu := ds.l.MakeSymbolUpdater(ds.s)
tds := t.(dwSym)
ds := loader.Sym(s.(dwSym))
dsu := c.ldr.MakeSymbolUpdater(ds)
tds := loader.Sym(t.(dwSym))
switch size {
default:
c.linkctxt.Errorf(ds.s, "invalid size %d in adddwarfref\n", size)
c.linkctxt.Errorf(ds, "invalid size %d in adddwarfref\n", size)
fallthrough
case c.arch.PtrSize:
dsu.AddAddrPlus(c.arch, tds.s, 0)
dsu.AddAddrPlus(c.arch, tds, 0)
case 4:
dsu.AddAddrPlus4(c.arch, tds.s, 0)
dsu.AddAddrPlus4(c.arch, tds, 0)
}
rsl := dsu.Relocs()
r := &rsl[len(rsl)-1]
@ -139,8 +149,8 @@ func (c dwctxt2) AddDWARFAddrSectionOffset(s dwarf.Sym, t interface{}, ofs int64
c.AddSectionOffset(s, size, t, ofs)
ds := s.(dwSym)
dsu := ds.l.MakeSymbolUpdater(ds.s)
ds := loader.Sym(s.(dwSym))
dsu := c.ldr.MakeSymbolUpdater(ds)
rsl := dsu.Relocs()
r := &rsl[len(rsl)-1]
r.Type = objabi.R_DWARFSECREF
@ -168,23 +178,6 @@ func (c dwctxt2) RecordChildDieOffsets(s dwarf.Sym, vars []*dwarf.Var, offsets [
panic("should be used only in the compiler")
}
// dwSym wraps a loader.Sym; objects of this type are stored
// in the 'Sym' field of dwarf.DIE objects.
//
// FIXME: the main reason we need the loader.Loader pointer field is
// that the dwarf.Sym interface has a Len() method with no parameters.
// If we changed this method to accept a dwxtxt (from which we could
// access the loader) then we could get rid of this field and/or avoid
// using a struct.
type dwSym struct {
s loader.Sym
l *loader.Loader
}
func (s dwSym) Len() int64 {
return int64(len(s.l.Data(s.s)))
}
var gdbscript string
var dwarfp2 []loader.Sym
@ -264,7 +257,7 @@ func (d *dwctxt2) newdie(parent *dwarf.DWDie, abbrev int, name string, version i
dsu.SetType(sym.SDWARFINFO)
d.ldr.SetAttrNotInSymbolTable(ds, true)
d.ldr.SetAttrReachable(ds, true)
die.Sym = dwSym{s: ds, l: d.ldr}
die.Sym = dwSym(ds)
if abbrev >= dwarf.DW_ABRV_NULLTYPE && abbrev <= dwarf.DW_ABRV_TYPEDECL {
d.tmap[name] = ds
}
@ -361,15 +354,15 @@ func (d *dwctxt2) newrefattr(die *dwarf.DWDie, attr uint16, ref loader.Sym) *dwa
if ref == 0 {
return nil
}
return newattr(die, attr, dwarf.DW_CLS_REFERENCE, 0, dwSym{s: ref, l: d.ldr})
return newattr(die, attr, dwarf.DW_CLS_REFERENCE, 0, dwSym(ref))
}
func (d *dwctxt2) dtolsym(s dwarf.Sym) loader.Sym {
if s == nil {
return 0
}
dws := s.(dwSym)
return dws.s
dws := loader.Sym(s.(dwSym))
return dws
}
func (d *dwctxt2) putdie(syms []loader.Sym, die *dwarf.DWDie) []loader.Sym {
@ -405,7 +398,7 @@ func newmemberoffsetattr(die *dwarf.DWDie, offs int32) {
// GDB doesn't like FORM_addr for AT_location, so emit a
// location expression that evals to a const.
func (d *dwctxt2) newabslocexprattr(die *dwarf.DWDie, addr int64, symIdx loader.Sym) {
newattr(die, dwarf.DW_AT_location, dwarf.DW_CLS_ADDRESS, addr, dwSym{s: symIdx, l: d.ldr})
newattr(die, dwarf.DW_AT_location, dwarf.DW_CLS_ADDRESS, addr, dwSym(symIdx))
}
func (d *dwctxt2) lookupOrDiag(n string) loader.Sym {
@ -444,7 +437,7 @@ func (d *dwctxt2) dotypedef(parent *dwarf.DWDie, gotype loader.Sym, name string,
tds := d.ldr.CreateExtSym("")
tdsu := d.ldr.MakeSymbolUpdater(tds)
tdsu.SetType(sym.SDWARFINFO)
def.Sym = dwSym{s: tds, l: d.ldr}
def.Sym = dwSym(tds)
d.ldr.SetAttrNotInSymbolTable(tds, true)
d.ldr.SetAttrReachable(tds, true)
@ -483,8 +476,8 @@ func (d *dwctxt2) defgotype(gotype loader.Sym) loader.Sym {
}
gtdwSym := d.newtype(gotype)
d.tdmap[gotype] = gtdwSym.Sym.(dwSym).s
return gtdwSym.Sym.(dwSym).s
d.tdmap[gotype] = loader.Sym(gtdwSym.Sym.(dwSym))
return loader.Sym(gtdwSym.Sym.(dwSym))
}
func (d *dwctxt2) newtype(gotype loader.Sym) *dwarf.DWDie {
@ -654,7 +647,7 @@ func (d *dwctxt2) newtype(gotype loader.Sym) *dwarf.DWDie {
newattr(die, dwarf.DW_AT_go_kind, dwarf.DW_CLS_CONSTANT, int64(kind), 0)
if d.ldr.AttrReachable(gotype) {
newattr(die, dwarf.DW_AT_go_runtime_type, dwarf.DW_CLS_GO_TYPEREF, 0, dwSym{s: gotype, l: d.ldr})
newattr(die, dwarf.DW_AT_go_runtime_type, dwarf.DW_CLS_GO_TYPEREF, 0, dwSym(gotype))
}
// Sanity check.
@ -662,11 +655,11 @@ func (d *dwctxt2) newtype(gotype loader.Sym) *dwarf.DWDie {
log.Fatalf("internal error: rtmap entry already installed\n")
}
ds := die.Sym.(dwSym)
ds := loader.Sym(die.Sym.(dwSym))
if typedefdie != nil {
ds = typedefdie.Sym.(dwSym)
ds = loader.Sym(typedefdie.Sym.(dwSym))
}
d.rtmap[ds.s] = gotype
d.rtmap[ds] = gotype
if _, ok := prototypedies[sn]; ok {
prototypedies[sn] = die
@ -702,13 +695,13 @@ func (d *dwctxt2) defptrto(dwtype loader.Sym) loader.Sym {
// pointers of slices. Link to the ones we can find.
gts := d.ldr.Lookup("type."+ptrname, 0)
if gts != 0 && d.ldr.AttrReachable(gts) {
newattr(pdie, dwarf.DW_AT_go_runtime_type, dwarf.DW_CLS_GO_TYPEREF, 0, dwSym{s: gts, l: d.ldr})
newattr(pdie, dwarf.DW_AT_go_runtime_type, dwarf.DW_CLS_GO_TYPEREF, 0, dwSym(gts))
}
if gts != 0 {
ds := pdie.Sym.(dwSym)
d.rtmap[ds.s] = gts
d.tdmap[gts] = ds.s
ds := loader.Sym(pdie.Sym.(dwSym))
d.rtmap[ds] = gts
d.tdmap[gts] = ds
}
return d.dtolsym(pdie.Sym)
@ -748,7 +741,7 @@ func (d *dwctxt2) substitutetype(structdie *dwarf.DWDie, field string, dwtype lo
a := getattr(child, dwarf.DW_AT_type)
if a != nil {
a.Data = dwSym{s: dwtype, l: d.ldr}
a.Data = dwSym(dwtype)
} else {
d.newrefattr(child, dwarf.DW_AT_type, dwtype)
}
@ -791,7 +784,7 @@ func (d *dwctxt2) synthesizeslicetypes(ctxt *Link, die *dwarf.DWDie) {
continue
}
d.copychildren(ctxt, die, prototype)
elem := getattr(die, dwarf.DW_AT_go_elem).Data.(dwSym).s
elem := loader.Sym(getattr(die, dwarf.DW_AT_go_elem).Data.(dwSym))
d.substitutetype(die, "array", d.defptrto(elem))
}
}
@ -834,7 +827,7 @@ func (d *dwctxt2) synthesizemaptypes(ctxt *Link, die *dwarf.DWDie) {
if die.Abbrev != dwarf.DW_ABRV_MAPTYPE {
continue
}
gotype := getattr(die, dwarf.DW_AT_type).Data.(dwSym).s
gotype := loader.Sym(getattr(die, dwarf.DW_AT_type).Data.(dwSym))
keytype := decodetypeMapKey2(d.ldr, d.arch, gotype)
valtype := decodetypeMapValue2(d.ldr, d.arch, gotype)
keydata := d.ldr.Data(keytype)
@ -932,7 +925,7 @@ func (d *dwctxt2) synthesizechantypes(ctxt *Link, die *dwarf.DWDie) {
if die.Abbrev != dwarf.DW_ABRV_CHANTYPE {
continue
}
elemgotype := getattr(die, dwarf.DW_AT_type).Data.(dwSym).s
elemgotype := loader.Sym(getattr(die, dwarf.DW_AT_type).Data.(dwSym))
tname := d.ldr.SymName(elemgotype)
elemname := tname[5:]
elemtype := d.walksymtypedef(d.defgotype(d.lookupOrDiag(tname)))
@ -1200,11 +1193,11 @@ func (d *dwctxt2) mkBuiltinType(ctxt *Link, abrv int, tname string) *dwarf.DWDie
gotype := d.lookupOrDiag("type." + tname)
// Map from die sym to type sym
ds := die.Sym.(dwSym)
d.rtmap[ds.s] = gotype
ds := loader.Sym(die.Sym.(dwSym))
d.rtmap[ds] = gotype
// Map from type to def sym
d.tdmap[gotype] = ds.s
d.tdmap[gotype] = ds
return die
}
@ -1241,7 +1234,7 @@ func dwarfGenerateDebugInfo2(ctxt *Link) {
newattr(die, dwarf.DW_AT_encoding, dwarf.DW_CLS_CONSTANT, dwarf.DW_ATE_unsigned, 0)
newattr(die, dwarf.DW_AT_byte_size, dwarf.DW_CLS_CONSTANT, int64(d.arch.PtrSize), 0)
newattr(die, dwarf.DW_AT_go_kind, dwarf.DW_CLS_CONSTANT, objabi.KindUintptr, 0)
newattr(die, dwarf.DW_AT_go_runtime_type, dwarf.DW_CLS_ADDRESS, 0, dwSym{s: d.lookupOrDiag("type.uintptr"), l: d.ldr})
newattr(die, dwarf.DW_AT_go_runtime_type, dwarf.DW_CLS_ADDRESS, 0, dwSym(d.lookupOrDiag("type.uintptr")))
d.uintptrInfoSym = d.mustFind("uintptr")
@ -1515,19 +1508,19 @@ func convertSymbolsInDIE(ctxt *Link, die *dwarf.DWDie, convdies map[*dwarf.DWDie
}
convdies[die] = true
if die.Sym != nil {
symIdx, ok := die.Sym.(dwSym)
ds, ok := die.Sym.(dwSym)
if !ok {
panic("bad die sym field")
}
ls := symIdx.s
if ls == 0 {
symIdx := loader.Sym(ds)
if symIdx == 0 {
panic("zero loader sym for die")
}
die.Sym = ctxt.loader.Syms[symIdx.s]
die.Sym = ctxt.loader.Syms[symIdx]
}
for a := die.Attr; a != nil; a = a.Link {
if attrSym, ok := a.Data.(dwSym); ok {
a.Data = ctxt.loader.Syms[attrSym.s]
a.Data = ctxt.loader.Syms[loader.Sym(attrSym)]
}
}
convertSymbolsInDIE(ctxt, die.Child, convdies)

4
src/cmd/link/internal/sym/symbol.go
View File

@ -103,6 +103,10 @@ func (s *Symbol) Len() int64 {
return s.Size
}
func (s *Symbol) Length(dwarfContext interface{}) int64 {
return s.Size
}
func (s *Symbol) Grow(siz int64) {
if int64(int(siz)) != siz {
log.Fatalf("symgrow size %d too long", siz)