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Diffstat (limited to 'instrumentation/README.out_of_line.md')
-rw-r--r-- | instrumentation/README.out_of_line.md | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/instrumentation/README.out_of_line.md b/instrumentation/README.out_of_line.md new file mode 100644 index 00000000..aad215b6 --- /dev/null +++ b/instrumentation/README.out_of_line.md @@ -0,0 +1,21 @@ +=========================================== +Using afl++ without inlined instrumentation +=========================================== + + This file describes how you can disable inlining of instrumentation. + + +By default, the GCC plugin will duplicate the effects of calling +__afl_trace (see afl-gcc-rt.o.c) in instrumented code, instead of +issuing function calls. + +The calls are presumed to be slower, more so because the rt file +itself is not optimized by the compiler. + +Setting AFL_GCC_OUT_OF_LINE=1 in the environment while compiling code +with the plugin will disable this inlining, issuing calls to the +unoptimized runtime instead. + +You probably don't want to do this, but it might be useful in certain +AFL debugging scenarios, and it might work as a fallback in case +something goes wrong with the inlined instrumentation. |