[llvm-demangle-fuzzer] Add a fuzz target for ItaniumDemangler.

Patch By: hctim

Reviewers: morehouse, bogner

Reviewed By: bogner

Subscribers: bogner, kcc, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D38855

llvm-svn: 315716
diff --git a/llvm/tools/llvm-demangle-fuzzer/llvm-demangle-fuzzer.cpp b/llvm/tools/llvm-demangle-fuzzer/llvm-demangle-fuzzer.cpp
new file mode 100644
index 0000000..07c290a
--- /dev/null
+++ b/llvm/tools/llvm-demangle-fuzzer/llvm-demangle-fuzzer.cpp
@@ -0,0 +1,24 @@
+//===--- llvm-demangle-fuzzer.cpp - Fuzzer for the Itanium Demangler ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Demangle/Demangle.h"
+
+#include <cstdint>
+#include <cstdlib>
+#include <string>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  std::string NullTerminatedString((const char *)Data, Size);
+  int status = 0;
+  if (char *demangle = llvm::itaniumDemangle(NullTerminatedString.c_str(), nullptr,
+                                         nullptr, &status))
+    free(demangle);
+
+  return 0;
+}