[libFuzzer] make sure the input data is not overwritten in the fuzz target (if it is -- report an error)

llvm-svn: 302494

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/Fuzzer/test/OverwriteInputTest.cpp b/llvm/lib/Fuzzer/test/OverwriteInputTest.cpp
new file mode 100644
index 00000000000..e688682346a
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/OverwriteInputTest.cpp
@@ -0,0 +1,13 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. Make sure we abort if Data is overwritten.
+#include <cstdint>
+#include <iostream>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size)
+    *const_cast<uint8_t*>(Data) = 1;
+  return 0;
+}
+