cmd/compile: merge Node.Opt and Node.Val behind access methods
$ sizeof -p cmd/compile/internal/gc Node
Node 144
$
Change-Id: I688e3790964fe42f48c19f697ec38094a92fe1c1
Reviewed-on: https://go-review.googlesource.com/10531
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/cmd/compile/internal/gc/syntax.go b/src/cmd/compile/internal/gc/syntax.go
index 773de8b..b66ab2e 100644
--- a/src/cmd/compile/internal/gc/syntax.go
+++ b/src/cmd/compile/internal/gc/syntax.go
@@ -30,12 +30,8 @@
// ONAME
Name *Name
- Sym *Sym // various
-
- Opt interface{} // for optimization passes
-
- // OLITERAL
- Val Val
+ Sym *Sym // various
+ E interface{} // Opt or Val, see methods below
Xoffset int64
@@ -69,6 +65,49 @@
Assigned bool // is the variable ever assigned to
Likely int8 // likeliness of if statement
Hasbreak bool // has break statement
+ hasVal int8 // +1 for Val, -1 for Opt, 0 for not yet set
+}
+
+// Val returns the Val for the node.
+func (n *Node) Val() Val {
+ if n.hasVal != +1 {
+ return Val{}
+ }
+ return Val{n.E}
+}
+
+// SetVal sets the Val for the node, which must not have been used with SetOpt.
+func (n *Node) SetVal(v Val) {
+ if n.hasVal == -1 {
+ Debug['h'] = 1
+ Dump("have Opt", n)
+ Fatal("have Opt")
+ }
+ n.hasVal = +1
+ n.E = v.U
+}
+
+// Opt returns the optimizer data for the node.
+func (n *Node) Opt() interface{} {
+ if n.hasVal != -1 {
+ return nil
+ }
+ return n.E
+}
+
+// SetOpt sets the optimizer data for the node, which must not have been used with SetVal.
+// SetOpt(nil) is ignored for Vals to simplify call sites that are clearing Opts.
+func (n *Node) SetOpt(x interface{}) {
+ if x == nil && n.hasVal >= 0 {
+ return
+ }
+ if n.hasVal == +1 {
+ Debug['h'] = 1
+ Dump("have Val", n)
+ Fatal("have Val")
+ }
+ n.hasVal = -1
+ n.E = x
}
// Name holds Node fields used only by named nodes (ONAME, OPACK, some OLITERAL).
