Index: lib/Fuzzer/FuzzerDriver.cpp =================================================================== --- lib/Fuzzer/FuzzerDriver.cpp +++ lib/Fuzzer/FuzzerDriver.cpp @@ -336,6 +336,7 @@ Options.PrintNewCovPcs = Flags.print_new_cov_pcs; Options.PrintFinalStats = Flags.print_final_stats; Options.TruncateUnits = Flags.truncate_units; + Options.PruneCorpus = Flags.prune_corpus; unsigned Seed = Flags.seed; // Initialize Seed. Index: lib/Fuzzer/FuzzerFlags.def =================================================================== --- lib/Fuzzer/FuzzerFlags.def +++ lib/Fuzzer/FuzzerFlags.def @@ -85,6 +85,8 @@ FUZZER_FLAG_INT(rss_limit_mb, 2048, "If non-zero, the fuzzer will exit upon" "reaching this limit of RSS memory usage.") FUZZER_FLAG_INT(truncate_units, 0, "Try truncated units when loading corpus.") +FUZZER_FLAG_INT(prune_corpus, 1, "Prune corpus items without new coverage when " + "loading corpus.") FUZZER_DEPRECATED_FLAG(exit_on_first) FUZZER_DEPRECATED_FLAG(save_minimized_corpus) Index: lib/Fuzzer/FuzzerInternal.h =================================================================== --- lib/Fuzzer/FuzzerInternal.h +++ lib/Fuzzer/FuzzerInternal.h @@ -331,6 +331,7 @@ bool PrintFinalStats = false; bool DetectLeaks = true; bool TruncateUnits = false; + bool PruneCorpus = true; }; // Aggregates all available coverage measurements. Index: lib/Fuzzer/FuzzerLoop.cpp =================================================================== --- lib/Fuzzer/FuzzerLoop.cpp +++ lib/Fuzzer/FuzzerLoop.cpp @@ -400,7 +400,8 @@ } for (const auto &U : Corpus) { - if (RunOne(U)) { + bool NewCoverage = RunOne(U); + if (!Options.PruneCorpus || NewCoverage) { NewCorpus.push_back(U); if (Options.Verbosity >= 2) Printf("NEW0: %zd L %zd\n", MaxCoverage.BlockCoverage, U.size()); Index: lib/Fuzzer/test/fuzzer-prunecorpus.test =================================================================== --- /dev/null +++ lib/Fuzzer/test/fuzzer-prunecorpus.test @@ -0,0 +1,13 @@ +RUN: rm -rf %t/PruneCorpus +RUN: mkdir -p %t/PruneCorpus +RUN: echo a > %t/PruneCorpus/a +RUN: echo b > %t/PruneCorpus/b +RUN: LLVMFuzzer-EmptyTest %t/PruneCorpus -prune_corpus=1 -runs=0 2>&1 | FileCheck %s --check-prefix=PRUNE +RUN: LLVMFuzzer-EmptyTest %t/PruneCorpus -prune_corpus=0 -runs=0 2>&1 | FileCheck %s --check-prefix=NOPRUNE +RUN: rm -rf %t/PruneCorpus + +PRUNE: READ units: 2 +PRUNE: INITED{{.*}}units: 1 +NOPRUNE: READ units: 2 +NOPRUNE: INITED{{.*}}units: 2 +