Bug 1334062 - Remove libFuzzer dependencies from fuzzers r=franziskus

Differential Revision: https://nss-review.dev.mozaws.net/D177

1 files changed, 15 insertions, 14 deletions

diff --git a/fuzz/shared.h b/fuzz/shared.h
index bfa4e8f52..24ca51f85 100644
--- a/fuzz/shared.h
+++ b/fuzz/shared.h
@@ -7,33 +7,34 @@
 #ifndef shared_h__
 #define shared_h__
 
-#include "FuzzerRandom.h"
+#include <assert.h>
+#include <random>
 #include "cert.h"
 #include "nss.h"
 
+extern "C" size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize);
+extern "C" size_t LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size,
+                                          size_t MaxSize, unsigned int Seed);
+
 class NSSDatabase {
  public:
   NSSDatabase() { assert(NSS_NoDB_Init(nullptr) == SECSuccess); }
   ~NSSDatabase() { assert(NSS_Shutdown() == SECSuccess); }
 };
 
-size_t CustomMutate(std::vector<decltype(LLVMFuzzerCustomMutator) *> mutators,
-                    uint8_t *Data, size_t Size, size_t MaxSize,
-                    unsigned int Seed) {
-  fuzzer::Random R(Seed);
+typedef std::vector<decltype(LLVMFuzzerCustomMutator) *> Mutators;
+
+size_t CustomMutate(Mutators &mutators, uint8_t *Data, size_t Size,
+                    size_t MaxSize, unsigned int Seed) {
+  std::mt19937 rng(Seed);
+  static std::bernoulli_distribution bdist;
 
-  if (R.RandBool()) {
-    auto idx = R(mutators.size());
-    return mutators.at(idx)(Data, Size, MaxSize, Seed);
+  if (bdist(rng)) {
+    std::uniform_int_distribution<size_t> idist(0, mutators.size() - 1);
+    return mutators.at(idist(rng))(Data, Size, MaxSize, Seed);
   }
 
   return LLVMFuzzerMutate(Data, Size, MaxSize);
 }
 
-#define ADD_CUSTOM_MUTATORS(...)                                       \
-  extern "C" size_t LLVMFuzzerCustomMutator(                           \
-      uint8_t *Data, size_t Size, size_t MaxSize, unsigned int Seed) { \
-    return CustomMutate(__VA_ARGS__, Data, Size, MaxSize, Seed);       \
-  }
-
 #endif  // shared_h__