Kostya Serebryany be5e0ed919 [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		2015-03-03 23:27:02 +00:00
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sanitizer	[sanitizer/coverage] Add AFL-style coverage counters (search heuristic for fuzzing).	2015-03-03 23:27:02 +00:00
CMakeLists.txt	[sanitizer] move the coverage interface into a separate header, <sanitizer/coverage_interface.h>. NFC, except for the header name change. This may break existing users, but in this case it's better this way (not too many users so far)	2015-02-03 19:40:53 +00:00