commit 1b4a701c1618bdda331f3ee506c7e8fc177a1c8f
author Matt Morehouse <mascasa@google.com> Fri Aug 17 01:30:27 2018 +0000
committer Copybara-Service <copybara-worker@google.com> Thu Mar 25 23:17:56 2021 -0700
tree a73e5ae2ace87a1fd75356f861df1db06f1a1a21
parent dd6dde65f145e08e49bb4ba64e7c518520c8e23b

Revert "[libFuzzer] Use std::discrete_distribution for input selection."

This reverts r339973 due to msan.test failing on
sanitizer-x86_64-linux-fuzzer bot.

llvm-svn: 339976
GitOrigin-RevId: be57e8e328696870abf4cf168e80114710476552

FuzzerCorpus.h

diff --git a/FuzzerCorpus.h b/FuzzerCorpus.h
index 11f5f1b..8ad1465 100644
--- a/FuzzerCorpus.h
+++ b/FuzzerCorpus.h
@@ -174,7 +174,7 @@
 
   // Returns an index of random unit from the corpus to mutate.
   size_t ChooseUnitIdxToMutate(Random &Rand) {
-    size_t Idx = CorpusDistribution(Rand);
+    size_t Idx = static_cast<size_t>(CorpusDistribution(Rand));
     assert(Idx < Inputs.size());
     return Idx;
   }
@@ -276,7 +276,9 @@
   void UpdateCorpusDistribution() {
     size_t N = Inputs.size();
     assert(N);
+    Intervals.resize(N + 1);
     Weights.resize(N);
+    std::iota(Intervals.begin(), Intervals.end(), 0);
     for (size_t i = 0; i < N; i++)
       Weights[i] = Inputs[i]->NumFeatures
                        ? (i + 1) * (Inputs[i]->HasFocusFunction ? 1000 : 1)
@@ -289,11 +291,12 @@
         Printf("%f ", Weights[i]);
       Printf("Weights\n");
     }
-    CorpusDistribution =
-        std::discrete_distribution<size_t>(Weights.begin(), Weights.end());
+    CorpusDistribution = std::piecewise_constant_distribution<double>(
+        Intervals.begin(), Intervals.end(), Weights.begin());
   }
-  std::discrete_distribution<size_t> CorpusDistribution;
+  std::piecewise_constant_distribution<double> CorpusDistribution;
 
+  Vector<double> Intervals;
   Vector<double> Weights;
 
   std::unordered_set<std::string> Hashes;