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| author | Kostya Serebryany <kcc@google.com> | 2015-03-03 23:27:02 +0000 |
|---|---|---|
| committer | Kostya Serebryany <kcc@google.com> | 2015-03-03 23:27:02 +0000 |
| commit | be5e0ed919e20bf6b1d0c8b7d96188a00f686738 (patch) | |
| tree | 6559b1628040f2a99cd78421dbe65ae26d4f44cc /llvm/cmake/modules | |
| parent | 6f1e5680f64c3313561128b4f2a24275fa635b9c (diff) | |
| download | bcm5719-llvm-be5e0ed919e20bf6b1d0c8b7d96188a00f686738.tar.gz bcm5719-llvm-be5e0ed919e20bf6b1d0c8b7d96188a00f686738.zip | |
[sanitizer/coverage] Add AFL-style coverage counters (search heuristic for fuzzing).
Introduce -mllvm -sanitizer-coverage-8bit-counters=1
which adds imprecise thread-unfriendly 8-bit coverage counters.
The run-time library maps these 8-bit counters to 8-bit bitsets in the same way
AFL (http://lcamtuf.coredump.cx/afl/technical_details.txt) does:
counter values are divided into 8 ranges and based on the counter
value one of the bits in the bitset is set.
The AFL ranges are used here: 1, 2, 3, 4-7, 8-15, 16-31, 32-127, 128+.
These counters provide a search heuristic for single-threaded
coverage-guided fuzzers, we do not expect them to be useful for other purposes.
Depending on the value of -fsanitize-coverage=[123] flag,
these counters will be added to the function entry blocks (=1),
every basic block (=2), or every edge (=3).
Use these counters as an optional search heuristic in the Fuzzer library.
Add a test where this heuristic is critical.
llvm-svn: 231166
Diffstat (limited to 'llvm/cmake/modules')
| -rw-r--r-- | llvm/cmake/modules/HandleLLVMOptions.cmake | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake index fdc4ea0b4ac..45b4d3278cb 100644 --- a/llvm/cmake/modules/HandleLLVMOptions.cmake +++ b/llvm/cmake/modules/HandleLLVMOptions.cmake @@ -424,7 +424,7 @@ if(LLVM_USE_SANITIZER) message(WARNING "LLVM_USE_SANITIZER is not supported on this platform.") endif() if (LLVM_USE_SANITIZE_COVERAGE) - append("-fsanitize-coverage=4" CMAKE_C_FLAGS CMAKE_CXX_FLAGS) + append("-fsanitize-coverage=4 -mllvm -sanitizer-coverage-8bit-counters=1" CMAKE_C_FLAGS CMAKE_CXX_FLAGS) endif() endif() |
