cmd/compile/internal/inline: fix latent CalleeEffects issue

ir.ClosureExpr implements ir.InitNode, so ir.InitExpr can prepend init
statements to it. However, CalleeEffects wasn't aware of this and
could cause the init statements to get dropped when inlining a call to
a closure.

This isn't an issue today, because we don't create closures with init
statements. But I ran into this within unified IR.

Easy and robust solution: just take advantage that ir.TakeInit can
handle any node.

Change-Id: Ica05fbf6a8c5be4b11927daf84491a1140da5431
Reviewed-on: https://go-review.googlesource.com/c/go/+/422196
Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>

diff --git a/src/cmd/compile/internal/inline/inl.go b/src/cmd/compile/internal/inline/inl.go
index 77848577c6b5ced3690565055d09b12426e3d20a..795486f7a2c992b9b9ffa110451347236c120f25 100644 (file)
--- a/src/cmd/compile/internal/inline/inl.go
+++ b/src/cmd/compile/internal/inline/inl.go
@@ -827,18 +827,18 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b
 // CalleeEffects appends any side effects from evaluating callee to init.
 func CalleeEffects(init *ir.Nodes, callee ir.Node) {
        for {
+               init.Append(ir.TakeInit(callee)...)
+
                switch callee.Op() {
                case ir.ONAME, ir.OCLOSURE, ir.OMETHEXPR:
                        return // done
 
                case ir.OCONVNOP:
                        conv := callee.(*ir.ConvExpr)
-                       init.Append(ir.TakeInit(conv)...)
                        callee = conv.X
 
                case ir.OINLCALL:
                        ic := callee.(*ir.InlinedCallExpr)
-                       init.Append(ir.TakeInit(ic)...)
                        init.Append(ic.Body.Take()...)
                        callee = ic.SingleResult()