[libfuzzer] custom crossover interface function.

Differential Revision: http://reviews.llvm.org/D21089

llvm-svn: 272054

3 files changed, 68 insertions, 0 deletions

diff --git a/llvm/lib/Fuzzer/test/CMakeLists.txt b/llvm/lib/Fuzzer/test/CMakeLists.txt
index 6d05ec1dedf..85fb62e3345 100644
--- a/llvm/lib/Fuzzer/test/CMakeLists.txt
+++ b/llvm/lib/Fuzzer/test/CMakeLists.txt
@@ -66,6 +66,7 @@ set(Tests
   BufferOverflowOnInput
   CallerCalleeTest
   CounterTest
+  CustomCrossOverTest
   CustomMutatorTest
   EmptyTest
   FourIndependentBranchesTest
diff --git a/llvm/lib/Fuzzer/test/CustomCrossOverTest.cpp b/llvm/lib/Fuzzer/test/CustomCrossOverTest.cpp
new file mode 100644
index 00000000000..2ab5781155f
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/CustomCrossOverTest.cpp
@@ -0,0 +1,57 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a cutom mutator.
+#include <assert.h>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+#include <random>
+#include <string.h>
+
+#include "FuzzerInterface.h"
+
+static const char *Separator = "-_^_-";
+static const char *Target = "012-_^_-abc";
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  std::string Str(reinterpret_cast<const char *>(Data), Size);
+
+  if (Str.find(Target) != std::string::npos) {
+    std::cout << "BINGO; Found the target, exiting\n";
+    exit(1);
+  }
+  return 0;
+}
+
+extern "C" size_t LLVMFuzzerCustomCrossOver(const uint8_t *Data1, size_t Size1,
+                                            const uint8_t *Data2, size_t Size2,
+                                            uint8_t *Out, size_t MaxOutSize,
+                                            unsigned int Seed) {
+  static bool Printed;
+  static size_t SeparatorLen = strlen(Separator);
+
+  if (!Printed) {
+    std::cerr << "In LLVMFuzzerCustomCrossover\n";
+    Printed = true;
+  }
+
+  std::mt19937 R(Seed);
+
+  size_t Offset1 = 0;
+  size_t Len1 = R() % (Size1 - Offset1);
+  size_t Offset2 = 0;
+  size_t Len2 = R() % (Size2 - Offset2);
+  size_t Size = Len1 + Len2 + SeparatorLen;
+
+  if (Size > MaxOutSize)
+    return 0;
+
+  memcpy(Out, Data1 + Offset1, Len1);
+  memcpy(Out + Len1, Separator, SeparatorLen);
+  memcpy(Out + Len1 + SeparatorLen, Data2 + Offset2, Len2);
+
+  return Len1 + Len2 + SeparatorLen;
+}
diff --git a/llvm/lib/Fuzzer/test/fuzzer-customcrossover.test b/llvm/lib/Fuzzer/test/fuzzer-customcrossover.test
new file mode 100644
index 00000000000..4be54d3f799
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/fuzzer-customcrossover.test
@@ -0,0 +1,10 @@
+RUN: rm -rf %t/CustomCrossover
+RUN: mkdir -p %t/CustomCrossover
+RUN: echo "0123456789" > %t/CustomCrossover/digits
+RUN: echo "abcdefghij" > %t/CustomCrossover/chars
+RUN: not LLVMFuzzer-CustomCrossOverTest -seed=1 -use_memcmp=0 -runs=100000 -prune_corpus=0 %t/CustomCrossover 2>&1 | FileCheck %s --check-prefix=LLVMFuzzerCustomCrossover
+RUN: rm -rf %t/CustomCrossover
+
+LLVMFuzzerCustomCrossover: In LLVMFuzzerCustomCrossover
+LLVMFuzzerCustomCrossover: BINGO
+