Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/test/fixedbugs/issue19078.go b/test/fixedbugs/issue19078.go
new file mode 100644
index 0000000..b19e874
--- /dev/null
+++ b/test/fixedbugs/issue19078.go
@@ -0,0 +1,42 @@
+// run
+
+// Copyright 2017 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.
+
+// Issue 19078: liveness & zero-initialization of results
+// when there is a defer.
+package main
+
+import "unsafe"
+
+func main() {
+	// Construct an invalid pointer.  We do this by
+	// making a pointer which points to the unused space
+	// between the last 48-byte object in a span and the
+	// end of the span (there are 32 unused bytes there).
+	p := new([48]byte)              // make a 48-byte object
+	sink = &p                       // escape it, so it allocates for real
+	u := uintptr(unsafe.Pointer(p)) // get its address
+	u = u >> 13 << 13               // round down to page size
+	u += 1<<13 - 1                  // add almost a page
+
+	for i := 0; i < 1000000; i++ {
+		_ = identity(u)         // installs u at return slot
+		_ = liveReturnSlot(nil) // incorrectly marks return slot as live
+	}
+}
+
+//go:noinline
+func liveReturnSlot(x *int) *int {
+	defer func() {}() // causes return slot to be marked live
+	sink = &x         // causes x to be moved to the heap, triggering allocation
+	return x
+}
+
+//go:noinline
+func identity(x uintptr) uintptr {
+	return x
+}
+
+var sink interface{}