cmd/internal/obj: unexport Link.Hash

A prior CL eliminated the last reference to Ctxt.Hash
from the compiler.

Change-Id: Ic97ff84ed1a14e0c93fb0e8ec0b2617c3397c0e8
Reviewed-on: https://go-review.googlesource.com/40699
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/plive.go

@@ -1135,7 +1135,7 @@ func livenessemit(lv *Liveness, argssym, livesym *obj.LSym) {
 	// so that they can be de-duplicated.
 	// This provides significant binary size savings.
 	// It is safe to rename these LSyms because
-	// they are tracked separately from ctxt.Hash.
+	// they are tracked separately from ctxt.hash.
 	argssym.Name = fmt.Sprintf("gclocals·%x", md5.Sum(argssym.P))
 	livesym.Name = fmt.Sprintf("gclocals·%x", md5.Sum(livesym.P))
 }

src/cmd/internal/obj/line_test.go

@@ -12,7 +12,7 @@ import (
 
 func TestLinkgetlineFromPos(t *testing.T) {
 	ctxt := new(Link)
-	ctxt.Hash = make(map[SymVer]*LSym)
+	ctxt.hash = make(map[SymVer]*LSym)
 
 	afile := src.NewFileBase("a.go", "a.go")
 	bfile := src.NewFileBase("b.go", "/foo/bar/b.go")

src/cmd/internal/obj/link.go

@@ -761,7 +761,7 @@ type Link struct {
 	Flag_optimize bool
 	Bso           *bufio.Writer
 	Pathname      string
-	Hash          map[SymVer]*LSym
+	hash          map[SymVer]*LSym
 	PosTable      src.PosTable
 	InlTree       InlTree // global inlining tree used by gc/inl.go
 	Imports       []string

src/cmd/internal/obj/sym.go

@@ -53,7 +53,7 @@ func WorkingDir() string {
 
 func Linknew(arch *LinkArch) *Link {
 	ctxt := new(Link)
-	ctxt.Hash = make(map[SymVer]*LSym)
+	ctxt.hash = make(map[SymVer]*LSym)
 	ctxt.Arch = arch
 	ctxt.Pathname = WorkingDir()
 
@@ -76,13 +76,13 @@ func (ctxt *Link) Lookup(name string, v int) *LSym {
 // LookupInit looks up the symbol with name name and version v.
 // If it does not exist, it creates it and passes it to initfn for one-time initialization.
 func (ctxt *Link) LookupInit(name string, v int, init func(s *LSym)) *LSym {
-	s := ctxt.Hash[SymVer{name, v}]
+	s := ctxt.hash[SymVer{name, v}]
 	if s != nil {
 		return s
 	}
 
 	s = &LSym{Name: name, Version: int16(v)}
-	ctxt.Hash[SymVer{name, v}] = s
+	ctxt.hash[SymVer{name, v}] = s
 	if init != nil {
 		init(s)
 	}