X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FFuzzer%2FFuzzerMutate.cpp;h=f537fa90fd8506f13bdcab44f70fffd3ec78058b;hb=00552e3875ee5f382db6c98286a241a7d0efe1b8;hp=2db8fac9bc69ff05adc734b68d4e5ee0fa02608b;hpb=c9baf3befbdbfd43da91d99929cebe4f2266b32d;p=oota-llvm.git

diff --git a/lib/Fuzzer/FuzzerMutate.cpp b/lib/Fuzzer/FuzzerMutate.cpp
index 2db8fac9bc6..f537fa90fd8 100644
--- a/lib/Fuzzer/FuzzerMutate.cpp
+++ b/lib/Fuzzer/FuzzerMutate.cpp
@@ -9,6 +9,8 @@
 // Mutate a test input.
 //===----------------------------------------------------------------------===//
 
+#include <cstring>
+
 #include "FuzzerInternal.h"
 
 namespace fuzzer {
@@ -31,32 +33,39 @@ static char RandCh() {
   return Special[rand() % (sizeof(Special) - 1)];
 }
 
-void Mutate(Unit *U, size_t MaxLen) {
-  assert(MaxLen > 0);
-  assert(U->size() <= MaxLen);
+// Mutates Data in place, returns new size.
+size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
+  assert(MaxSize > 0);
+  assert(Size <= MaxSize);
+  if (Size == 0) {
+    for (size_t i = 0; i < MaxSize; i++)
+      Data[i] = RandCh();
+    return MaxSize;
+  }
+  assert(Size > 0);
+  size_t Idx = rand() % Size;
   switch (rand() % 3) {
   case 0:
-    if (U->size())
-      U->erase(U->begin() + rand() % U->size());
-    break;
+    if (Size > 1) {
+      // Erase Data[Idx].
+      memmove(Data + Idx, Data + Idx + 1, Size - Idx - 1);
+      Size = Size - 1;
+    }
+    [[clang::fallthrough]];
   case 1:
-    if (U->empty()) {
-      U->push_back(RandCh());
-    } else if (U->size() < MaxLen) {
-      U->insert(U->begin() + rand() % U->size(), RandCh());
-    } else { // At MaxLen.
-      uint8_t Ch = RandCh();
-      size_t Idx = rand() % U->size();
-      (*U)[Idx] = Ch;
+    if (Size < MaxSize) {
+      // Insert new value at Data[Idx].
+      memmove(Data + Idx + 1, Data + Idx, Size - Idx);
+      Data[Idx] = RandCh();
     }
+    Data[Idx] = RandCh();
     break;
-  default:
-    if (!U->empty()) {
-      size_t idx = rand() % U->size();
-      (*U)[idx] = FlipRandomBit((*U)[idx]);
-    }
+  case 2:
+    Data[Idx] = FlipRandomBit(Data[Idx]);
     break;
   }
+  assert(Size > 0);
+  return Size;
 }
 
 }  // namespace fuzzer