1 files changed, 13 insertions, 12 deletions
diff --git a/llvm/lib/Fuzzer/FuzzerMutate.cpp b/llvm/lib/Fuzzer/FuzzerMutate.cpp
index f537fa90fd8..66df98a66f5 100644
--- a/llvm/lib/Fuzzer/FuzzerMutate.cpp
+++ b/llvm/lib/Fuzzer/FuzzerMutate.cpp
@@ -15,8 +15,8 @@
 
 namespace fuzzer {
 
-static char FlipRandomBit(char X) {
-  int Bit = rand() % 8;
+static char FlipRandomBit(char X, FuzzerRandomBase &Rand) {
+  int Bit = Rand(8);
   char Mask = 1 << Bit;
   char R;
   if (X & (1 << Bit))
@@ -27,24 +27,25 @@ static char FlipRandomBit(char X) {
   return R;
 }
 
-static char RandCh() {
-  if (rand() % 2) return rand();
+static char RandCh(FuzzerRandomBase &Rand) {
+  if (Rand.RandBool()) return Rand(256);
   const char *Special = "!*'();:@&=+$,/?%#[]123ABCxyz-`~.";
-  return Special[rand() % (sizeof(Special) - 1)];
+  return Special[Rand(sizeof(Special) - 1)];
 }
 
 // Mutates Data in place, returns new size.
-size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
+size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize,
+              FuzzerRandomBase &Rand) {
   assert(MaxSize > 0);
   assert(Size <= MaxSize);
   if (Size == 0) {
     for (size_t i = 0; i < MaxSize; i++)
-      Data[i] = RandCh();
+      Data[i] = RandCh(Rand);
     return MaxSize;
   }
   assert(Size > 0);
-  size_t Idx = rand() % Size;
-  switch (rand() % 3) {
+  size_t Idx = Rand(Size);
+  switch (Rand(3)) {
   case 0:
     if (Size > 1) {
       // Erase Data[Idx].
@@ -56,12 +57,12 @@ size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
     if (Size < MaxSize) {
       // Insert new value at Data[Idx].
       memmove(Data + Idx + 1, Data + Idx, Size - Idx);
-      Data[Idx] = RandCh();
+      Data[Idx] = RandCh(Rand);
     }
-    Data[Idx] = RandCh();
+    Data[Idx] = RandCh(Rand);
     break;
   case 2:
-    Data[Idx] = FlipRandomBit(Data[Idx]);
+    Data[Idx] = FlipRandomBit(Data[Idx], Rand);
     break;
   }
   assert(Size > 0);