[libFuzzer] extend the -fork=1 functionality. Still not fully usable, but good enough for the first unit test

llvm-svn: 353775

1 files changed, 5 insertions, 0 deletions

diff --git a/compiler-rt/lib/fuzzer/FuzzerRandom.h b/compiler-rt/lib/fuzzer/FuzzerRandom.h
index f475797871c..af8e1a4eb71 100644
--- a/compiler-rt/lib/fuzzer/FuzzerRandom.h
+++ b/compiler-rt/lib/fuzzer/FuzzerRandom.h
@@ -20,6 +20,11 @@ class Random : public std::mt19937 {
   result_type operator()() { return this->std::mt19937::operator()(); }
   size_t Rand() { return this->operator()(); }
   size_t RandBool() { return Rand() % 2; }
+  size_t SkewTowardsLast(size_t n) {
+    size_t T = this->operator()(n * n);
+    size_t Res = sqrt(T);
+    return Res;
+  }
   size_t operator()(size_t n) { return n ? Rand() % n : 0; }
   intptr_t operator()(intptr_t From, intptr_t To) {
     assert(From < To);