custom mutator: libfuzzer LLVMFuzzerMutate()

This uses the libfuzzer LLVMFuzzerMutate() function in llvm 12.

just type make to build

AFL_CUSTOM_MUTATOR_LIBRARY=custom_mutators/libfuzzer/libfuzzer-mutator.so afl-fuzz ...

Note that this is currently a simple implementation and it is missing two features:

• Splicing ("Crossover")
• Dictionary support

To update the source, all that is needed is that FuzzerDriver.cpp has to receive

#include "libfuzzer.inc"

before the closing namespace bracket.

It is also libfuzzer.inc where the configuration of the libfuzzer mutations are done.

Original repository: https://github.com/llvm/llvm-project Path: compiler-rt/lib/fuzzer/*.{h|cpp} Source commit: df3e903655e2499968fc7af64fb5fa52b2ee79bb