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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227252 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 44 insertions, 0 deletions

diff --git a/lib/Fuzzer/FuzzerIO.cpp b/lib/Fuzzer/FuzzerIO.cpp
new file mode 100644
index 00000000000..172540c4603
--- /dev/null
+++ b/lib/Fuzzer/FuzzerIO.cpp
@@ -0,0 +1,44 @@
+//===- FuzzerIO.cpp - IO utils. -------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// IO functions.
+//===----------------------------------------------------------------------===//
+#include "FuzzerInternal.h"
+#include <fstream>
+#include <dirent.h>
+namespace fuzzer {
+
+std::vector<std::string> ListFilesInDir(const std::string &Dir) {
+  std::vector<std::string> V;
+  DIR *D = opendir(Dir.c_str());
+  if (!D) return V;
+  while (auto E = readdir(D)) {
+    if (E->d_type == DT_REG || E->d_type == DT_LNK)
+      V.push_back(E->d_name);
+  }
+  closedir(D);
+  return V;
+}
+
+Unit FileToVector(const std::string &Path) {
+  std::ifstream T(Path);
+  return Unit((std::istreambuf_iterator<char>(T)),
+              std::istreambuf_iterator<char>());
+}
+
+void WriteToFile(const Unit &U, const std::string &Path) {
+  std::ofstream OF(Path);
+  OF.write((const char*)U.data(), U.size());
+}
+
+void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V) {
+  for (auto &X : ListFilesInDir(Path))
+    V->push_back(FileToVector(std::string(Path) + "/" + X));
+}
+
+}  // namespace fuzzer