cmd/compile: pack bool fields in Node, Name, Func and Type structs to bitsets

This reduces compiler memory usage by up to 4% - see compilebench
results below.

name       old time/op     new time/op     delta
Template       245ms ± 4%      241ms ± 2%  -1.88%  (p=0.029 n=10+10)
Unicode        126ms ± 3%      124ms ± 3%    ~     (p=0.105 n=10+10)
GoTypes        805ms ± 2%      813ms ± 3%    ~     (p=0.515 n=8+10)
Compiler       3.95s ± 2%      3.83s ± 1%  -2.96%  (p=0.000 n=9+10)
MakeBash       47.4s ± 4%      46.6s ± 1%  -1.59%  (p=0.028 n=9+10)

name       old user-ns/op  new user-ns/op  delta
Template        324M ± 5%       326M ± 3%    ~     (p=0.935 n=10+10)
Unicode         186M ± 5%       178M ±10%    ~     (p=0.067 n=9+10)
GoTypes        1.08G ± 7%      1.09G ± 4%    ~     (p=0.956 n=10+10)
Compiler       5.34G ± 4%      5.31G ± 1%    ~     (p=0.501 n=10+8)

name       old alloc/op    new alloc/op    delta
Template      41.0MB ± 0%     39.8MB ± 0%  -3.03%  (p=0.000 n=10+10)
Unicode       32.3MB ± 0%     31.0MB ± 0%  -4.13%  (p=0.000 n=10+10)
GoTypes        119MB ± 0%      116MB ± 0%  -2.39%  (p=0.000 n=10+10)
Compiler       499MB ± 0%      487MB ± 0%  -2.48%  (p=0.000 n=10+10)

name       old allocs/op   new allocs/op   delta
Template        380k ± 1%       379k ± 1%    ~     (p=0.436 n=10+10)
Unicode         324k ± 1%       324k ± 0%    ~     (p=0.853 n=10+10)
GoTypes        1.15M ± 0%      1.15M ± 0%    ~     (p=0.481 n=10+10)
Compiler       4.41M ± 0%      4.41M ± 0%  -0.12%  (p=0.007 n=10+10)

name       old text-bytes  new text-bytes  delta
HelloSize       623k ± 0%       623k ± 0%    ~     (all equal)
CmdGoSize      6.64M ± 0%      6.64M ± 0%    ~     (all equal)

name       old data-bytes  new data-bytes  delta
HelloSize      5.81k ± 0%      5.81k ± 0%    ~     (all equal)
CmdGoSize       238k ± 0%       238k ± 0%    ~     (all equal)

name       old bss-bytes   new bss-bytes   delta
HelloSize       134k ± 0%       134k ± 0%    ~     (all equal)
CmdGoSize       152k ± 0%       152k ± 0%    ~     (all equal)

name       old exe-bytes   new exe-bytes   delta
HelloSize       967k ± 0%       967k ± 0%    ~     (all equal)
CmdGoSize      10.2M ± 0%      10.2M ± 0%    ~     (all equal)

Change-Id: I1f40af738254892bd6c8ba2eb43390b175753d52
Reviewed-on: https://go-review.googlesource.com/37445
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

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

@@ -38,7 +38,7 @@ func addrescapes(n *Node) {
 		}
 
 		// If a closure reference escapes, mark the outer variable as escaping.
-		if n.isClosureVar() {
+		if n.IsClosureVar() {
 			addrescapes(n.Name.Defn)
 			break
 		}
@@ -119,7 +119,7 @@ func moveToHeap(n *Node) {
 	// Unset AutoTemp to persist the &foo variable name through SSA to
 	// liveness analysis.
 	// TODO(mdempsky/drchase): Cleaner solution?
-	heapaddr.Name.AutoTemp = false
+	heapaddr.Name.SetAutoTemp(false)
 
 	// Parameters have a local stack copy used at function start/end
 	// in addition to the copy in the heap that may live longer than
@@ -145,7 +145,7 @@ func moveToHeap(n *Node) {
 			// Thus, we need the pointer to the heap copy always available so the
 			// post-deferreturn code can copy the return value back to the stack.
 			// See issue 16095.
-			heapaddr.setIsOutputParamHeapAddr(true)
+			heapaddr.SetIsOutputParamHeapAddr(true)
 		}
 		n.Name.Param.Stackcopy = stackcopy
 
@@ -207,11 +207,11 @@ func tempname(nn *Node, t *Type) {
 	s.Def = n
 	n.Type = t
 	n.Class = PAUTO
-	n.Addable = true
+	n.SetAddable(true)
 	n.Ullman = 1
 	n.Esc = EscNever
 	n.Name.Curfn = Curfn
-	n.Name.AutoTemp = true
+	n.Name.SetAutoTemp(true)
 	Curfn.Func.Dcl = append(Curfn.Func.Dcl, n)
 
 	dowidth(t)
@@ -222,6 +222,6 @@ func tempname(nn *Node, t *Type) {
 func temp(t *Type) *Node {
 	var n Node
 	tempname(&n, t)
-	n.Sym.Def.Used = true
+	n.Sym.Def.SetUsed(true)
 	return n.Orig
 }