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-rw-r--r--test/fixedbugs/issue27695b.go64
1 files changed, 64 insertions, 0 deletions
diff --git a/test/fixedbugs/issue27695b.go b/test/fixedbugs/issue27695b.go
new file mode 100644
index 0000000..d80acfb
--- /dev/null
+++ b/test/fixedbugs/issue27695b.go
@@ -0,0 +1,64 @@
+// run
+
+// Copyright 2018 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.
+
+// Make sure return values aren't scanned until they
+// are initialized, when calling functions and methods
+// via reflect.
+
+package main
+
+import (
+ "reflect"
+ "runtime"
+ "unsafe"
+)
+
+var badPtr uintptr
+
+var sink []byte
+
+func init() {
+ // Allocate large enough to use largeAlloc.
+ b := make([]byte, 1<<16-1)
+ sink = b // force heap allocation
+ // Any space between the object and the end of page is invalid to point to.
+ badPtr = uintptr(unsafe.Pointer(&b[len(b)-1])) + 1
+}
+
+func f(d func() *byte) *byte {
+ // Initialize callee args section with a bad pointer.
+ g(badPtr)
+
+ // Then call a function which returns a pointer.
+ // That return slot starts out holding a bad pointer.
+ return d()
+}
+
+//go:noinline
+func g(x uintptr) {
+}
+
+type T struct {
+}
+
+func (t *T) Foo() *byte {
+ runtime.GC()
+ return nil
+}
+
+func main() {
+ // Functions
+ d := reflect.MakeFunc(reflect.TypeOf(func() *byte { return nil }),
+ func(args []reflect.Value) []reflect.Value {
+ runtime.GC()
+ return []reflect.Value{reflect.ValueOf((*byte)(nil))}
+ }).Interface().(func() *byte)
+ f(d)
+
+ // Methods
+ e := reflect.ValueOf(&T{}).Method(0).Interface().(func() *byte)
+ f(e)
+}