[libFuzzer] introduce LLVMFuzzerInitialize

llvm-svn: 257980
diff --git a/llvm/lib/Fuzzer/test/InitializeTest.cpp b/llvm/lib/Fuzzer/test/InitializeTest.cpp
new file mode 100644
index 0000000..1462747
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/InitializeTest.cpp
@@ -0,0 +1,23 @@
+// Make sure LLVMFuzzerInitialize is called.
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static char *argv0;
+
+extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv) {
+  assert(argc > 0);
+  argv0 = **argv;
+  return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (strncmp(reinterpret_cast<const char*>(Data), argv0, Size)) {
+    fprintf(stderr, "BINGO\n");
+    exit(1);
+  }
+  return 0;
+}