[libFuzzer] suggest a dictionary to the user of some of the trace-based dictionary entries were successful

llvm-svn: 257736

1 files changed, 19 insertions, 0 deletions

diff --git a/llvm/lib/Fuzzer/test/RepeatedMemcmp.cpp b/llvm/lib/Fuzzer/test/RepeatedMemcmp.cpp
new file mode 100644
index 00000000000..cb5e130003b
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/RepeatedMemcmp.cpp
@@ -0,0 +1,19 @@
+
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  int Matches = 0;
+  for (size_t i = 0; i + 2 < Size; i += 3) {
+    const char *Pat = i % 2 ? "foo" : "bar";
+    if (!memcmp(Data + i, Pat, 3))
+      Matches++;
+  }
+  if (Matches > 20) {
+    fprintf(stderr, "BINGO!\n");
+    exit(1);
+  }
+  return 0;
+}