cmd/compile: fix defer/deferreturn
Make sure we do any just-before-return cleanup on all paths out of a
function, including when recovering. Each exit path should include
deferreturn (if there are any defers) and then the exit
code (e.g. copying heap-escaping return values back to the stack).
Introduce a Defer SSA block type which has two outgoing edges - one the
fallthrough edge (the defer was queued successfully) and one which
immediately returns (the defer had a successful recover() call and
normal execution should resume at the return point).
Fixes #14725
Change-Id: Iad035c9fd25ef8b7a74dafbd7461cf04833d981f
Reviewed-on: https://go-review.googlesource.com/20486
Reviewed-by: David Chase <drchase@google.com>
diff --git a/test/fixedbugs/issue14725.go b/test/fixedbugs/issue14725.go
new file mode 100644
index 0000000..cbdf5a3
--- /dev/null
+++ b/test/fixedbugs/issue14725.go
@@ -0,0 +1,57 @@
+// run
+
+// Copyright 2016 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 "fmt"
+
+func f1() (x int) {
+ for {
+ defer func() {
+ recover()
+ x = 1
+ }()
+ panic(nil)
+ }
+}
+
+var sink *int
+
+func f2() (x int) {
+ sink = &x
+ defer func() {
+ recover()
+ x = 1
+ }()
+ panic(nil)
+}
+
+func f3(b bool) (x int) {
+ sink = &x
+ defer func() {
+ recover()
+ x = 1
+ }()
+ if b {
+ panic(nil)
+ }
+ return
+}
+
+func main() {
+ if x := f1(); x != 1 {
+ panic(fmt.Sprintf("f1 returned %d, wanted 1", x))
+ }
+ if x := f2(); x != 1 {
+ panic(fmt.Sprintf("f2 returned %d, wanted 1", x))
+ }
+ if x := f3(true); x != 1 {
+ panic(fmt.Sprintf("f3(true) returned %d, wanted 1", x))
+ }
+ if x := f3(false); x != 1 {
+ panic(fmt.Sprintf("f3(false) returned %d, wanted 1", x))
+ }
+}
