cmd/compile: move lexn and lexname into lex.go (cleanup)

Missed these two declarations in the previous cleanup.

Change-Id: I54ff3accd387dd90e12847daccf4477169797f81
Reviewed-on: https://go-review.googlesource.com/20603
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

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

@@ -137,6 +137,54 @@ const (
 	LIGNORE
 )
 
+var lexn = map[rune]string{
+	LNAME:    "NAME",
+	LLITERAL: "LITERAL",
+
+	LOPER:  "OPER",
+	LASOP:  "ASOP",
+	LINCOP: "INCOP",
+
+	LCOLAS: "COLAS",
+	LCOMM:  "COMM",
+	LDDD:   "DDD",
+
+	LBREAK:     "BREAK",
+	LCASE:      "CASE",
+	LCHAN:      "CHAN",
+	LCONST:     "CONST",
+	LCONTINUE:  "CONTINUE",
+	LDEFAULT:   "DEFAULT",
+	LDEFER:     "DEFER",
+	LELSE:      "ELSE",
+	LFALL:      "FALL",
+	LFOR:       "FOR",
+	LFUNC:      "FUNC",
+	LGO:        "GO",
+	LGOTO:      "GOTO",
+	LIF:        "IF",
+	LIMPORT:    "IMPORT",
+	LINTERFACE: "INTERFACE",
+	LMAP:       "MAP",
+	LPACKAGE:   "PACKAGE",
+	LRANGE:     "RANGE",
+	LRETURN:    "RETURN",
+	LSELECT:    "SELECT",
+	LSTRUCT:    "STRUCT",
+	LSWITCH:    "SWITCH",
+	LTYPE:      "TYPE",
+	LVAR:       "VAR",
+
+	// LIGNORE is never escaping lexer.next
+}
+
+func lexname(lex rune) string {
+	if s, ok := lexn[lex]; ok {
+		return s
+	}
+	return fmt.Sprintf("LEX-%d", lex)
+}
+
 func (l *lexer) next() {
 	nlsemi := l.nlsemi
 	l.nlsemi = false

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

@@ -1057,52 +1057,6 @@ func lexfini() {
 	nodfp.Sym = Lookup(".fp")
 }
 
-var lexn = map[rune]string{
-	LNAME:    "NAME",
-	LLITERAL: "LITERAL",
-
-	LOPER:  "OPER",
-	LASOP:  "ASOP",
-	LINCOP: "INCOP",
-
-	LCOLAS: "COLAS",
-	LCOMM:  "COMM",
-	LDDD:   "DDD",
-
-	LBREAK:     "BREAK",
-	LCASE:      "CASE",
-	LCHAN:      "CHAN",
-	LCONST:     "CONST",
-	LCONTINUE:  "CONTINUE",
-	LDEFAULT:   "DEFAULT",
-	LDEFER:     "DEFER",
-	LELSE:      "ELSE",
-	LFALL:      "FALL",
-	LFOR:       "FOR",
-	LFUNC:      "FUNC",
-	LGO:        "GO",
-	LGOTO:      "GOTO",
-	LIF:        "IF",
-	LIMPORT:    "IMPORT",
-	LINTERFACE: "INTERFACE",
-	LMAP:       "MAP",
-	LPACKAGE:   "PACKAGE",
-	LRANGE:     "RANGE",
-	LRETURN:    "RETURN",
-	LSELECT:    "SELECT",
-	LSTRUCT:    "STRUCT",
-	LSWITCH:    "SWITCH",
-	LTYPE:      "TYPE",
-	LVAR:       "VAR",
-}
-
-func lexname(lex rune) string {
-	if s, ok := lexn[lex]; ok {
-		return s
-	}
-	return fmt.Sprintf("LEX-%d", lex)
-}
-
 func pkgnotused(lineno int32, path string, name string) {
 	// If the package was imported with a name other than the final
 	// import path element, show it explicitly in the error message.