[dev.regabi] cmd/compile: refactor temp construction in walk

This CL adds a few new helper functions for constructing and
initializing temporary variables during walk.

Passes toolstash -cmp.

Change-Id: I54965d992cd8dfef7cb7dc92a17c88372e52a0d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/284224
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, 7 insertions, 24 deletions

diff --git a/src/cmd/compile/internal/walk/complit.go b/src/cmd/compile/internal/walk/complit.go
index f82ef69ca99..a7db4535501 100644
--- a/src/cmd/compile/internal/walk/complit.go
+++ b/src/cmd/compile/internal/walk/complit.go
@@ -344,30 +344,14 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)
 		if !types.Identical(t, x.Type()) {
 			panic("dotdotdot base type does not match order's assigned type")
 		}
-
-		if vstat == nil {
-			a = ir.NewAssignStmt(base.Pos, x, nil)
-			a = typecheck.Stmt(a)
-			init.Append(a) // zero new temp
-		} else {
-			// Declare that we're about to initialize all of x.
-			// (Which happens at the *vauto = vstat below.)
-			init.Append(ir.NewUnaryExpr(base.Pos, ir.OVARDEF, x))
-		}
-
-		a = typecheck.NodAddr(x)
+		a = initStackTemp(init, x, vstat != nil)
 	} else if n.Esc() == ir.EscNone {
-		a = typecheck.Temp(t)
 		if vstat == nil {
-			a = ir.NewAssignStmt(base.Pos, typecheck.Temp(t), nil)
-			a = typecheck.Stmt(a)
-			init.Append(a) // zero new temp
-			a = a.(*ir.AssignStmt).X
-		} else {
-			init.Append(ir.NewUnaryExpr(base.Pos, ir.OVARDEF, a))
+			// TODO(mdempsky): Remove this useless temporary.
+			// It's only needed to keep toolstash happy.
+			typecheck.Temp(t)
 		}
-
-		a = typecheck.NodAddr(a)
+		a = initStackTemp(init, typecheck.Temp(t), vstat != nil)
 	} else {
 		a = ir.NewUnaryExpr(base.Pos, ir.ONEW, ir.TypeNode(t))
 	}
@@ -550,9 +534,8 @@ func anylit(n ir.Node, var_ ir.Node, init *ir.Nodes) {
 
 		var r ir.Node
 		if n.Prealloc != nil {
-			// n.Right is stack temporary used as backing store.
-			appendWalkStmt(init, ir.NewAssignStmt(base.Pos, n.Prealloc, nil)) // zero backing store, just in case (#18410)
-			r = typecheck.NodAddr(n.Prealloc)
+			// n.Prealloc is stack temporary used as backing store.
+			r = initStackTemp(init, n.Prealloc, false)
 		} else {
 			r = ir.NewUnaryExpr(base.Pos, ir.ONEW, ir.TypeNode(n.X.Type()))
 			r.SetEsc(n.Esc())