[libc-commits] [libc] [libc] add hashtable fuzzing (PR #87949)

[Michael Jones via libc-commits]

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@@ -0,0 +1,182 @@
+//===-- hashtable_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 hashtable implementations.
+///
+//===----------------------------------------------------------------------===//
+#include "include/llvm-libc-types/ENTRY.h"
+#include "src/__support/CPP/string_view.h"
+#include "src/__support/HashTable/table.h"
+
+namespace LIBC_NAMESPACE {
+
+// A fuzzing payload starts with
+// - uint16_t: initial capacity for table A
+// - uint64_t: seed for table A
+// - uint16_t: initial capacity for table B
+// - uint64_t: seed for table B
+// Followed by a sequence of actions:
+// - CrossCheck: only a single byte valued (4 mod 5)
+// - Find: a single byte valued (3 mod 5) followed by a null-terminated string
+// - Insert: a single byte valued (0,1,2 mod 5) followed by a null-terminated
+// string
+static constexpr size_t INITIAL_HEADER_SIZE =
+    2 * (sizeof(uint16_t) + sizeof(uint64_t));
+extern "C" size_t LLVMFuzzerMutate(uint8_t *data, size_t size, size_t max_size);
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michaelrj-google wrote:

I've been looking into moving to https://github.com/google/fuzztest as the fuzzing framework for our fuzz tests in future. It seems like this might be easier with that framework, if you are interested in trying it.

https://github.com/llvm/llvm-project/pull/87949