[libFuzzer] Add INFO output when LLVMFuzzerCustomMutator is found.
Summary:
there is an ongoing work on interchangeable custom mutators
(https://github.com/google/clusterfuzz/pull/1333/files#r367706283)
and having some sort of signalling from libFuzzer that it has loaded
a custom mutator would be helpful.
The initial idea was to make the mutator to print something, but given
the anticipated variety of different mutators, it does not seem possible
to make all of them print the same message to signal their execution.
Reviewers: kcc, metzman
Reviewed By: metzman
Subscribers: #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D73136
GitOrigin-RevId: 15f1d5d14425528540e1cc4aa776b195a2e1e7e0
diff --git a/FuzzerDriver.cpp b/FuzzerDriver.cpp
index dd3cab0..0063cde 100644
--- a/FuzzerDriver.cpp
+++ b/FuzzerDriver.cpp
@@ -195,8 +195,11 @@
}
// Disable len_control by default, if LLVMFuzzerCustomMutator is used.
- if (EF->LLVMFuzzerCustomMutator)
+ if (EF->LLVMFuzzerCustomMutator) {
Flags.len_control = 0;
+ Printf("INFO: found LLVMFuzzerCustomMutator (%p). "
+ "Disabling -len_control by default.\n", EF->LLVMFuzzerCustomMutator);
+ }
Inputs = new Vector<std::string>;
for (size_t A = 1; A < Args.size(); A++) {
