cmd/compile: preserve pointerness when creating map key temp

When creating the temporary for map functions, if the key
contains pointer, we need to create pointer-typed temporary. So
if the temporary is live across a function call, the pointer is
live.

Change-Id: Id6e14ec9def8bc7987f0f8ce8423caf1e3754fcb
Reviewed-on: https://go-review.googlesource.com/c/go/+/311379
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/test/abi/map.go b/test/abi/map.go
new file mode 100644
index 0000000000..236655a3af
--- /dev/null
+++ b/test/abi/map.go
@@ -0,0 +1,34 @@
+// run
+
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "runtime"
+
+type T [10]int
+
+var m map[*T]int
+
+//go:noinline
+func F() {
+	m = map[*T]int{
+		K(): V(), // the key temp should be live across call to V
+	}
+}
+
+//go:noinline
+func V() int { runtime.GC(); runtime.GC(); runtime.GC(); return 123 }
+
+//go:noinline
+func K() *T {
+	p := new(T)
+	runtime.SetFinalizer(p, func(*T) { println("FAIL") })
+	return p
+}
+
+func main() {
+	F()
+}