cmd/internal/obj: remove dead fields and code

A quick pass through link.go, mostly removing fields that are not
used on the "creating a single object file" side of the fence.

Change-Id: I35ba41378c2c418f7df2f2f88dce65bc64a1a45d
Reviewed-on: https://go-review.googlesource.com/7672
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/internal/obj/arm/asm5.go

@@ -1524,7 +1524,7 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
 
 	case 0: /* pseudo ops */
 		if false { /*debug['G']*/
-			fmt.Printf("%x: %s: arm %d\n", uint32(p.Pc), p.From.Sym.Name, p.From.Sym.Fnptr)
+			fmt.Printf("%x: %s: arm\n", uint32(p.Pc), p.From.Sym.Name)
 		}
 
 	case 1: /* op R,[R],R */

src/cmd/internal/obj/arm/obj5.go

@@ -115,7 +115,6 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 			if s.Type == 0 {
 				s.Type = obj.SRODATA
 				obj.Adduint32(ctxt, s, i32)
-				s.Reachable = 0
 			}
 
 			p.From.Type = obj.TYPE_MEM
@@ -132,7 +131,6 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 			if s.Type == 0 {
 				s.Type = obj.SRODATA
 				obj.Adduint64(ctxt, s, i64)
-				s.Reachable = 0
 			}
 
 			p.From.Type = obj.TYPE_MEM

src/cmd/internal/obj/data.go

@@ -121,7 +121,6 @@ func Setuintxx(ctxt *Link, s *LSym, off int64, v uint64, wid int64) int64 {
 	if s.Type == 0 {
 		s.Type = SDATA
 	}
-	s.Reachable = 1
 	if s.Size < off+wid {
 		s.Size = off + wid
 		Symgrow(ctxt, s, s.Size)
@@ -183,7 +182,6 @@ func addaddrplus(ctxt *Link, s *LSym, t *LSym, add int64) int64 {
 	if s.Type == 0 {
 		s.Type = SDATA
 	}
-	s.Reachable = 1
 	i := s.Size
 	s.Size += int64(ctxt.Arch.Ptrsize)
 	Symgrow(ctxt, s, s.Size)
@@ -200,7 +198,6 @@ func addpcrelplus(ctxt *Link, s *LSym, t *LSym, add int64) int64 {
 	if s.Type == 0 {
 		s.Type = SDATA
 	}
-	s.Reachable = 1
 	i := s.Size
 	s.Size += 4
 	Symgrow(ctxt, s, s.Size)
@@ -221,7 +218,6 @@ func setaddrplus(ctxt *Link, s *LSym, off int64, t *LSym, add int64) int64 {
 	if s.Type == 0 {
 		s.Type = SDATA
 	}
-	s.Reachable = 1
 	if off+int64(ctxt.Arch.Ptrsize) > s.Size {
 		s.Size = off + int64(ctxt.Arch.Ptrsize)
 		Symgrow(ctxt, s, s.Size)
@@ -244,7 +240,6 @@ func addsize(ctxt *Link, s *LSym, t *LSym) int64 {
 	if s.Type == 0 {
 		s.Type = SDATA
 	}
-	s.Reachable = 1
 	i := s.Size
 	s.Size += int64(ctxt.Arch.Ptrsize)
 	Symgrow(ctxt, s, s.Size)
@@ -260,7 +255,6 @@ func addaddrplus4(ctxt *Link, s *LSym, t *LSym, add int64) int64 {
 	if s.Type == 0 {
 		s.Type = SDATA
 	}
-	s.Reachable = 1
 	i := s.Size
 	s.Size += 4
 	Symgrow(ctxt, s, s.Size)

src/cmd/internal/obj/link.go

@@ -272,45 +272,20 @@ const (
 
 type LSym struct {
 	Name      string
-	Extname     string
 	Type      int16
 	Version   int16
 	Dupok     uint8
 	Cfunc     uint8
-	External    uint8
 	Nosplit   uint8
-	Reachable   uint8
-	Cgoexport   uint8
-	Special     uint8
-	Stkcheck    uint8
-	Hide        uint8
 	Leaf      uint8
-	Fnptr       uint8
-	Localentry  uint8
 	Seenglobl uint8
 	Onlist    uint8
-	Printed     uint8
-	Symid       int16
-	Dynid       int32
-	Plt         int32
-	Got         int32
-	Align       int32
-	Elfsym      int32
 	Args      int32
 	Locals    int32
 	Value     int64
 	Size      int64
-	Allsym      *LSym
 	Next      *LSym
-	Sub         *LSym
-	Outer       *LSym
 	Gotype    *LSym
-	Reachparent *LSym
-	Queue       *LSym
-	File        string
-	Dynimplib   string
-	Dynimpvers  string
-	Sect        *struct{}
 	Autom     *Auto
 	Text      *Prog
 	Etext     *Prog
@@ -376,9 +351,7 @@ const (
 type Reloc struct {
 	Off  int32
 	Siz  uint8
-	Done    uint8
 	Type int32
-	Variant int32
 	Add  int64
 	Xadd int64
 	Sym  *LSym
@@ -408,17 +381,6 @@ const (
 	R_POWER_TOC
 )
 
-// Reloc.variant
-const (
-	RV_NONE = iota
-	RV_POWER_LO
-	RV_POWER_HI
-	RV_POWER_HA
-	RV_POWER_DS
-	RV_CHECK_OVERFLOW = 1 << 8
-	RV_TYPE_MASK      = RV_CHECK_OVERFLOW - 1
-)
-
 type Auto struct {
 	Asym    *LSym
 	Link    *Auto
@@ -459,24 +421,15 @@ const (
 // Link holds the context for writing object code from a compiler
 // to be linker input or for reading that input into the linker.
 type Link struct {
-	Thechar            int32
-	Thestring          string
 	Goarm              int32
 	Headtype           int
 	Arch               *LinkArch
-	Ignore             func(string) int32
 	Debugasm           int32
-	Debugline          int32
-	Debughist          int32
-	Debugread          int32
 	Debugvlog          int32
-	Debugstack         int32
 	Debugzerostack     int32
 	Debugdivmod        int32
-	Debugfloat         int32
 	Debugpcln          int32
 	Flag_shared        int32
-	Iself              int32
 	Bso                *Biobuf
 	Pathname           string
 	Windows            int32
@@ -485,8 +438,6 @@ type Link struct {
 	Goroot_final       string
 	Enforce_data_order int32
 	Hash               map[SymVer]*LSym
-	Allsym             *LSym
-	Nsymbol            int32
 	LineHist           LineHist
 	Imports            []string
 	Plist              *Plist
@@ -513,20 +464,13 @@ type Link struct {
 	Autosize           int32
 	Armsize            int32
 	Pc                 int64
-	Libdir             []string
-	Library            []Library
 	Tlsoffset          int
 	Diag               func(string, ...interface{})
 	Mode               int
-	Curauto            *Auto
-	Curhist            *Auto
 	Cursym             *LSym
 	Version            int
 	Textp              *LSym
 	Etextp             *LSym
-	Histdepth          int32
-	Nhistfile          int32
-	Filesyms           *LSym
 }
 
 type SymVer struct {
@@ -534,13 +478,6 @@ type SymVer struct {
 	Version int
 }
 
-type Library struct {
-	Objref string
-	Srcref string
-	File   string
-	Pkg    string
-}
-
 // LinkArch is the definition of a single architecture.
 type LinkArch struct {
 	ByteOrder  binary.ByteOrder
@@ -572,14 +509,6 @@ const (
 	Hwindows
 )
 
-const (
-	LinkAuto = 0 + iota
-	LinkInternal
-	LinkExternal
-)
-
-var linkbasepointer int
-
 type Plist struct {
 	Name    *LSym
 	Firstpc *Prog

src/cmd/internal/obj/sym.go

@@ -225,18 +225,11 @@ func linknewsym(ctxt *Link, symb string, v int) *LSym {
 	s := new(LSym)
 	*s = LSym{}
 
-	s.Dynid = -1
-	s.Plt = -1
-	s.Got = -1
 	s.Name = symb
 	s.Type = 0
 	s.Version = int16(v)
 	s.Value = 0
 	s.Size = 0
-	ctxt.Nsymbol++
-
-	s.Allsym = ctxt.Allsym
-	ctxt.Allsym = s
 
 	return s
 }
@@ -248,7 +241,6 @@ func _lookup(ctxt *Link, symb string, v int, creat int) *LSym {
 	}
 
 	s = linknewsym(ctxt, symb, v)
-	s.Extname = s.Name
 	ctxt.Hash[SymVer{symb, v}] = s
 
 	return s

src/cmd/internal/obj/x86/obj6.go

@@ -246,7 +246,6 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 			if s.Type == 0 {
 				s.Type = obj.SRODATA
 				obj.Adduint32(ctxt, s, i32)
-				s.Reachable = 0
 			}
 
 			p.From.Type = obj.TYPE_MEM
@@ -290,7 +289,6 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
 			if s.Type == 0 {
 				s.Type = obj.SRODATA
 				obj.Adduint64(ctxt, s, i64)
-				s.Reachable = 0
 			}
 
 			p.From.Type = obj.TYPE_MEM