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Diffstat (limited to 'docs/env_variables.md')
| -rw-r--r-- | docs/env_variables.md | 34 |
1 files changed, 23 insertions, 11 deletions
diff --git a/docs/env_variables.md b/docs/env_variables.md index 8c7510cd..98f27bdf 100644 --- a/docs/env_variables.md +++ b/docs/env_variables.md @@ -93,23 +93,26 @@ Then there are a few specific features that are only available in llvm_mode: ### LTO -This is a different kind way of instrumentation: first it compiles all -code in LTO (link time optimization) and then performs an edge inserting -instrumentation which is 100% collision free (collisions are a big issue -in afl and afl-like instrumentations). This is performed by using -afl-clang-lto/afl-clang-lto++ instead of afl-clang-fast, but is only -built if LLVM 9 or newer is used. - -None of these options are necessary to be used and are rather for manual -use (which only ever the author of this LTO implementation will use ;-) -These are used if several seperated instrumentation are performed which -are then later combined. + This is a different kind way of instrumentation: first it compiles all + code in LTO (link time optimization) and then performs an edge inserting + instrumentation which is 100% collision free (collisions are a big issue + in afl and afl-like instrumentations). This is performed by using + afl-clang-lto/afl-clang-lto++ instead of afl-clang-fast, but is only + built if LLVM 9 or newer is used. + + None of these options are necessary to be used and are rather for manual + use (which only ever the author of this LTO implementation will use ;-) + These are used if several seperated instrumentation are performed which + are then later combined. - AFL_LLVM_LTO_STARTID sets the starting location ID for the instrumentation. This defaults to 1 - AFL_LLVM_LTO_DONTWRITEID prevents that the highest location ID written into the instrumentation is set in a global variable + Instrim, LTO and ngram modes can not be used together. + See llvm_mode/README.LTO.md for more information. + ### LAF-INTEL This great feature will split compares to series of single byte comparisons @@ -149,8 +152,17 @@ are then later combined. functions with a single basic block. This is useful for most C and some C++ targets. + Instrim, LTO and ngram modes can not be used together. See llvm_mode/README.instrim.md +### NGRAM + + - Setting AFL_LLVM_NGRAM_SIZE activates ngram prev_loc coverage, good + values are 2, 4 or 8. + + Instrim, LTO and ngram modes can not be used together. + See llvm_mode/README.ngram.md + ### NOT_ZERO - Setting AFL_LLVM_NOT_ZERO=1 during compilation will use counters |