cmd/link: add a test to test RODATA is indeed read-only

Updates #38830.

Change-Id: Ie1f6ccef40a773f038aac587dfc26bf70a1a8536
Reviewed-on: https://go-review.googlesource.com/c/go/+/253921
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/src/cmd/link/testdata/testRO/x.go b/src/cmd/link/testdata/testRO/x.go
new file mode 100644
index 0000000000..d77db6d563
--- /dev/null
+++ b/src/cmd/link/testdata/testRO/x.go
@@ -0,0 +1,22 @@
+// Copyright 2020 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.
+
+// Test that read-only data is indeed read-only. This
+// program attempts to modify read-only data, and it
+// should fail.
+
+package main
+
+import "unsafe"
+
+var s = "hello"
+
+func main() {
+	println(s)
+	*(*struct {
+		p *byte
+		l int
+	})(unsafe.Pointer(&s)).p = 'H'
+	println(s)
+}