cmd/internal/gc: remove unused fields

Change-Id: I3096a7497955bc475739739ee23be387e9162867
Reviewed-on: https://go-review.googlesource.com/7210
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/gc/go.go

@@ -112,7 +112,6 @@ type Pkg struct {
 type Sym struct {
 	Lexical   uint16
 	Flags     uint8
-	Sym       uint8 // huffman encoding in object file
 	Link      *Sym
 	Uniqgen   uint32
 	Importdef *Pkg   // where imported definition was found
@@ -399,7 +398,6 @@ type Sig struct {
 type Io struct {
 	infile     string
 	bin        *obj.Biobuf
-	ilineno    int32
 	nlsemi     int
 	eofnl      int
 	last       int

src/cmd/internal/gc/syntax.go

@@ -27,7 +27,6 @@ type Node struct {
 	Nointerface    bool
 	Ullman         uint8 // sethi/ullman number
 	Addable        uint8 // type of addressability - 0 is not addressable
-	Trecur         uint8 // to detect loops
 	Etype          uint8 // op for OASOP, etype for OTYPE, exclam for export
 	Bounded        bool  // bounds check unnecessary
 	Class          uint8 // PPARAM, PAUTO, PEXTERN, etc