summaryrefslogtreecommitdiffstats
path: root/test/fixedbugs/issue16249.go
diff options
context:
space:
mode:
Diffstat (limited to 'test/fixedbugs/issue16249.go')
-rw-r--r--test/fixedbugs/issue16249.go58
1 files changed, 58 insertions, 0 deletions
diff --git a/test/fixedbugs/issue16249.go b/test/fixedbugs/issue16249.go
new file mode 100644
index 0000000..723d5d9
--- /dev/null
+++ b/test/fixedbugs/issue16249.go
@@ -0,0 +1,58 @@
+// 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.
+
+// Liveness calculations were wrong for a result parameter pushed onto
+// the heap in a function that used defer. Program would crash with
+// runtime: bad pointer in frame main.A at 0xc4201e6838: 0x1
+
+package main
+
+import "errors"
+
+var sink interface{}
+
+//go:noinline
+func f(err *error) {
+ if err != nil {
+ sink = err
+ }
+}
+
+//go:noinline
+func A(n, m int64) (res int64, err error) {
+ defer f(&err) // output parameter's address escapes to a defer.
+ if n < 0 {
+ err = errors.New("No negative")
+ return
+ }
+ if n <= 1 {
+ res = n
+ return
+ }
+ res = B(m) // This call to B drizzles a little junk on the stack.
+ res, err = A(n-1, m)
+ res++
+ return
+}
+
+// B does a little bit of recursion dribbling not-zero onto the stack.
+//go:noinline
+func B(n int64) (res int64) {
+ if n <= 1 { // Prefer to leave a 1 on the stack.
+ return n
+ }
+ return 1 + B(n-1)
+}
+
+func main() {
+ x, e := A(0, 0)
+ for j := 0; j < 4; j++ { // j controls amount of B's stack dribble
+ for i := 0; i < 1000; i++ { // try more and more recursion until stack growth occurs in newobject in prologue
+ x, e = A(int64(i), int64(j))
+ }
+ }
+ _, _ = x, e
+}