[libFuzzer] Handle unstable edges by disregarding unstable edges
Summary:
Added a new mode within flag -handle_unstable for new unstable handling algorithm that does the following:
When an edge is shown as unstable, copy to UnstableCounters the value 0.
During ApplyUnstableCounters we copy back the value 0 to ModuleInline8bitCounters if the edge was unstable.
This way we would be ignoring completely features that were collected through non-determinism.
Unstable hits would be counted as if it never hit.
Reviewers: metzman, Dor1s, kcc, morehouse
Reviewed By: metzman, morehouse
Subscribers: delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D49684
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer@337853 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/FuzzerTracePC.cpp b/FuzzerTracePC.cpp
index 859ff63..29ffc8e 100644
--- a/FuzzerTracePC.cpp
+++ b/FuzzerTracePC.cpp
@@ -83,11 +83,14 @@
// and records differences as unstable edges.
void TracePC::UpdateUnstableCounters(int UnstableMode) {
IterateInline8bitCounters([&](int i, int j, int UnstableIdx) {
- if (ModuleCounters[i].Start[j] != UnstableCounters[UnstableIdx].Counter)
+ if (ModuleCounters[i].Start[j] != UnstableCounters[UnstableIdx].Counter) {
UnstableCounters[UnstableIdx].IsUnstable = true;
- if (UnstableMode &&
- ModuleCounters[i].Start[j] < UnstableCounters[UnstableIdx].Counter)
- UnstableCounters[UnstableIdx].Counter = ModuleCounters[i].Start[j];
+ if (UnstableMode == ZeroUnstable)
+ UnstableCounters[UnstableIdx].Counter = 0;
+ else if (UnstableMode == MinUnstable)
+ UnstableCounters[UnstableIdx].Counter = std::min(
+ ModuleCounters[i].Start[j], UnstableCounters[UnstableIdx].Counter);
+ }
});
}