Add a Fuzzer library

Summary:
A simple genetic in-process coverage-guided fuzz testing library.

I've used this fuzzer to test clang-format
(it found 12+ bugs, thanks djasper@ for the fixes!)
and it may also help us test other parts of LLVM.
So why not keep it in the LLVM repository?

I plan to add the cmake build rules later (in a separate patch, if that's ok)
and also add a clang-format-fuzzer target.

See README.txt for details.

Test Plan: Tests will follow separately.

Reviewers: djasper, chandlerc, rnk

Reviewed By: rnk

Subscribers: majnemer, ygribov, dblaikie, llvm-commits

Differential Revision: http://reviews.llvm.org/D7184

llvm-svn: 227252

1 files changed, 21 insertions, 0 deletions

diff --git a/llvm/lib/Fuzzer/test/ExactTest.cpp b/llvm/lib/Fuzzer/test/ExactTest.cpp
new file mode 100644
index 00000000000..662dd333eea
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/ExactTest.cpp
@@ -0,0 +1,21 @@
+// Simple test for a fuzzer. The fuzzer must find the string "FUZZER".
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+static volatile int Sink;
+
+extern "C" void TestOneInput(const uint8_t *Data, size_t Size) {
+  int bits = 0;
+  if (Size > 0 && Data[0] == 'F') bits |= 1;
+  if (Size > 1 && Data[1] == 'U') bits |= 2;
+  if (Size > 2 && Data[2] == 'Z') bits |= 4;
+  if (Size > 3 && Data[3] == 'Z') bits |= 8;
+  if (Size > 4 && Data[4] == 'E') bits |= 16;
+  if (Size > 5 && Data[5] == 'R') bits |= 32;
+  if (bits == 63) {
+    std::cerr <<  "BINGO!\n";
+    abort();
+  }
+}
+