cmd/yacc: generate arrays instead of slices where possible

Yacc generates a bunch of global variables of the form

    var yyFoo = []int{...}

where yyFoo is never subsequently modified to point to a different
slice.  Since these variables are implicitly compiled as

    var yyFoo = ([...]int{...})[:]

anyway, by simply converting them all to

    var yyFoo = [...]int{...}

we save sizeof(sliceStruct) bytes of data memory for each variable and
also make len(yyFoo) into compile-time constant expressions, which
shaves some bytes off text size:

    $ size 6g.before 6g.after
       text	   data	    bss	    dec	    hex	filename
    4598019	 605968	 342700	5546687	 54a2bf	6g.before
    4597810	 605552	 342700	5546062	 54a04e	6g.after

Change-Id: I53c7aa6efdb2d52738013e9d337a59afbfcb2494
Reviewed-on: https://go-review.googlesource.com/7520
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/internal/gc/go.y

@@ -2240,7 +2240,6 @@ hidden_interfacedcl_list:
 	}
 
 %%
-
 func fixlbrace(lbr int) {
 	// If the opening brace was an LBODY,
 	// set up for another one now that we're done.
@@ -2249,4 +2248,3 @@ func fixlbrace(lbr int) {
 		loophack = 1
 	}
 }
-

src/cmd/internal/gc/y.go

@@ -69,7 +69,7 @@ const NotPackage = 57392
 const NotParen = 57393
 const PreferToRightParen = 57394
 
-var yyToknames = []string{
+var yyToknames = [...]string{
 	"LLITERAL",
 	"LASOP",
 	"LCOLAS",
@@ -130,7 +130,7 @@ var yyToknames = []string{
 	"')'",
 	"PreferToRightParen",
 }
-var yyStatenames = []string{}
+var yyStatenames = [...]string{}
 
 const yyEofCode = 1
 const yyErrCode = 2
@@ -147,7 +147,7 @@ func fixlbrace(lbr int) {
 }
 
 //line yacctab:1
-var yyExca = []int{
+var yyExca = [...]int{
 	-1, 1,
 	1, -1,
 	-2, 0,
@@ -272,7 +272,7 @@ var yyStates []string
 
 const yyLast = 2282
 
-var yyAct = []int{
+var yyAct = [...]int{
 
 	74, 381, 304, 285, 291, 486, 610, 398, 545, 478,
 	549, 296, 186, 75, 400, 229, 302, 401, 103, 389,
@@ -504,7 +504,7 @@ var yyAct = []int{
 	137, 136, 0, 151, 141, 142, 143, 144, 145, 146,
 	147, 148,
 }
-var yyPact = []int{
+var yyPact = [...]int{
 
 	-1000, -1000, 542, 536, -1000, 164, -1000, 550, 555, 318,
 	-1000, -1000, -1000, 588, -1000, -1000, 549, 1340, 316, 155,
@@ -574,7 +574,7 @@ var yyPact = []int{
 	110, -1000, 37, 2017, -1000, -1000, 2017, -1000, -1000, -1000,
 	-1000, -1000, -1000, -1000, -1000, 1689, 518, -1000,
 }
-var yyPgo = []int{
+var yyPgo = [...]int{
 
 	0, 57, 771, 774, 45, 150, 26, 540, 29, 770,
 	768, 2, 28, 61, 322, 766, 17, 4, 765, 761,
@@ -592,7 +592,7 @@ var yyPgo = []int{
 	648, 647, 642, 639, 637, 634, 631, 627, 38, 623,
 	596, 593,
 }
-var yyR1 = []int{
+var yyR1 = [...]int{
 
 	0, 112, 114, 114, 116, 113, 115, 115, 119, 119,
 	119, 120, 120, 121, 121, 2, 2, 2, 117, 123,
@@ -631,7 +631,7 @@ var yyR1 = []int{
 	94, 94, 93, 93, 125, 125, 100, 100, 104, 104,
 	102, 102,
 }
-var yyR2 = []int{
+var yyR2 = [...]int{
 
 	0, 4, 0, 3, 0, 3, 0, 3, 2, 5,
 	3, 3, 2, 1, 3, 1, 2, 2, 4, 0,
@@ -670,7 +670,7 @@ var yyR2 = []int{
 	2, 1, 1, 5, 0, 2, 1, 3, 1, 3,
 	1, 3,
 }
-var yyChk = []int{
+var yyChk = [...]int{
 
 	-1000, -112, -113, -116, -114, 26, -117, 26, -115, -3,
 	25, -91, 74, 75, -118, -124, 25, -60, -119, 22,
@@ -740,7 +740,7 @@ var yyChk = []int{
 	15, 73, -58, 61, 61, 61, 61, -52, 67, 67,
 	21, -11, 69, -99, -99, -134, -24, -53,
 }
-var yyDef = []int{
+var yyDef = [...]int{
 
 	4, -2, 2, 0, 6, 0, 21, 0, 218, 0,
 	157, 158, 159, 0, 5, 344, 19, -2, 0, 0,
@@ -810,7 +810,7 @@ var yyDef = []int{
 	0, 133, 0, 335, 343, 337, 335, 206, 56, 57,
 	82, 87, 145, 333, 208, 294, 0, 83,
 }
-var yyTok1 = []int{
+var yyTok1 = [...]int{
 
 	1, 3, 3, 3, 3, 3, 3, 3, 3, 3,
 	3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
@@ -826,7 +826,7 @@ var yyTok1 = []int{
 	3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
 	3, 3, 3, 68, 52, 69, 71,
 }
-var yyTok2 = []int{
+var yyTok2 = [...]int{
 
 	2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
 	12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
@@ -835,7 +835,7 @@ var yyTok2 = []int{
 	42, 43, 44, 45, 46, 47, 48, 49, 58, 59,
 	62,
 }
-var yyTok3 = []int{
+var yyTok3 = [...]int{
 	0,
 }
 

src/cmd/yacc/yacc.go

@@ -517,14 +517,14 @@ outer:
 
 	// put out names of token names
 	ftable.WriteRune('\n')
-	fmt.Fprintf(ftable, "var %sToknames = []string{\n", prefix)
+	fmt.Fprintf(ftable, "var %sToknames = [...]string{\n", prefix)
 	for i := TOKSTART; i <= ntokens; i++ {
 		fmt.Fprintf(ftable, "\t\"%v\",\n", tokset[i].name)
 	}
 	fmt.Fprintf(ftable, "}\n")
 
 	// put out names of state names
-	fmt.Fprintf(ftable, "var %sStatenames = []string{", prefix)
+	fmt.Fprintf(ftable, "var %sStatenames = [...]string{", prefix)
 	//	for i:=TOKSTART; i<=ntokens; i++ {
 	//		fmt.Fprintf(ftable, "\t\"%v\",\n", tokset[i].name);
 	//	}
@@ -2156,7 +2156,7 @@ func output() {
 	if !lflag {
 		fmt.Fprintf(ftable, "\n//line yacctab:1")
 	}
-	fmt.Fprintf(ftable, "\nvar %sExca = []int{\n", prefix)
+	fmt.Fprintf(ftable, "\nvar %sExca = [...]int{\n", prefix)
 
 	noset := mkset()
 
@@ -2892,7 +2892,7 @@ func others() {
 	arout("Tok2", temp1, c+1)
 
 	// table 3 has everything else
-	fmt.Fprintf(ftable, "var %sTok3 = []int{\n\t", prefix)
+	fmt.Fprintf(ftable, "var %sTok3 = [...]int{\n\t", prefix)
 	c = 0
 	for i = 1; i <= ntokens; i++ {
 		j = tokset[i].value
@@ -2937,7 +2937,7 @@ func others() {
 
 func arout(s string, v []int, n int) {
 	s = prefix + s
-	fmt.Fprintf(ftable, "var %v = []int{\n", s)
+	fmt.Fprintf(ftable, "var %v = [...]int{\n", s)
 	for i := 0; i < n; i++ {
 		if i%10 == 0 {
 			fmt.Fprintf(ftable, "\n\t")