[dev.regabi] cmd/compile: simplify some tree traversal code

When looking for referenced functions within bottomUpVisitor and
initDeps, the logic for ODOTMETH, OCALLPART, and OMETHEXPR are
basically identical, especially after previous refactorings to make
them use MethodExprName. This CL makes them exactly identical.

Passes toolstash -cmp.

Change-Id: I1f59c9be99aa9484d0397a0a6fb8ddd894a31c68
Reviewed-on: https://go-review.googlesource.com/c/go/+/280441
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>

1 files changed, 14 insertions, 35 deletions

diff --git a/src/cmd/compile/internal/ir/scc.go b/src/cmd/compile/internal/ir/scc.go
index 4f646e22b5..f35c4d44e9 100644
--- a/src/cmd/compile/internal/ir/scc.go
+++ b/src/cmd/compile/internal/ir/scc.go
@@ -76,48 +76,27 @@ func (v *bottomUpVisitor) visit(n *Func) uint32 {
 	min := v.visitgen
 	v.stack = append(v.stack, n)
 
+	do := func(defn Node) {
+		if defn != nil {
+			if m := v.visit(defn.(*Func)); m < min {
+				min = m
+			}
+		}
+	}
+
 	Visit(n, func(n Node) {
 		switch n.Op() {
 		case ONAME:
-			n := n.(*Name)
-			if n.Class_ == PFUNC {
-				if n != nil && n.Name().Defn != nil {
-					if m := v.visit(n.Name().Defn.(*Func)); m < min {
-						min = m
-					}
-				}
+			if n := n.(*Name); n.Class_ == PFUNC {
+				do(n.Defn)
 			}
-		case OMETHEXPR:
-			n := n.(*MethodExpr)
-			fn := MethodExprName(n)
-			if fn != nil && fn.Defn != nil {
-				if m := v.visit(fn.Defn.(*Func)); m < min {
-					min = m
-				}
-			}
-		case ODOTMETH:
-			n := n.(*SelectorExpr)
-			fn := MethodExprName(n)
-			if fn != nil && fn.Op() == ONAME && fn.Class_ == PFUNC && fn.Defn != nil {
-				if m := v.visit(fn.Defn.(*Func)); m < min {
-					min = m
-				}
-			}
-		case OCALLPART:
-			n := n.(*CallPartExpr)
-			fn := AsNode(n.Method.Nname)
-			if fn != nil && fn.Op() == ONAME {
-				if fn := fn.(*Name); fn.Class_ == PFUNC && fn.Name().Defn != nil {
-					if m := v.visit(fn.Name().Defn.(*Func)); m < min {
-						min = m
-					}
-				}
+		case ODOTMETH, OCALLPART, OMETHEXPR:
+			if fn := MethodExprName(n); fn != nil {
+				do(fn.Defn)
 			}
 		case OCLOSURE:
 			n := n.(*ClosureExpr)
-			if m := v.visit(n.Func); m < min {
-				min = m
-			}
+			do(n.Func)
 		}
 	})