[libc-commits] [libc] [libc] Add memcmp / bcmp fuzzers (PR #77741)

[Clement Courbet via libc-commits]

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@@ -0,0 +1,52 @@
+//===-- bcmp_fuzz.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// Fuzzing test for llvm-libc bcmp implementation.
+///
+//===----------------------------------------------------------------------===//
+#include "src/string/bcmp.h"
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+static int reference_bcmp(const void *pa, const void *pb, size_t count)
+    __attribute__((no_builtin)) {
+  const auto *a = reinterpret_cast<const unsigned char *>(pa);
+  const auto *b = reinterpret_cast<const unsigned char *>(pb);
+  for (size_t i = 0; i < count; ++i, ++a, ++b)
+    if (*a != *b)
+      return 1;
+  return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  const auto normalize = [](int value) -> int {
+    if (value == 0)
+      return 0;
+    return 1;
+  };
+  const auto count = size / 2;
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legrosbuffle wrote:

`// We ignore the last byte is size is odd.`

https://github.com/llvm/llvm-project/pull/77741