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authorvan Hauser <vh@thc.org>2019-07-05 11:28:08 +0200
committervan Hauser <vh@thc.org>2019-07-05 11:28:08 +0200
commit7f6aaa53147afd4feb549214f49d0f5f69e4af6c (patch)
tree9e99e541b9df310af959b4ac8d893ec24ab3fd11 /docs
parent9199967022284da0ee4d78459d8d34513540cf32 (diff)
downloadafl++-7f6aaa53147afd4feb549214f49d0f5f69e4af6c.tar.gz
final touches
Diffstat (limited to 'docs')
-rw-r--r--docs/ChangeLog2
-rw-r--r--docs/env_variables.txt7
2 files changed, 7 insertions, 2 deletions
diff --git a/docs/ChangeLog b/docs/ChangeLog
index 73c69196..a533de05 100644
--- a/docs/ChangeLog
+++ b/docs/ChangeLog
@@ -17,6 +17,8 @@ sending a mail to <afl-users+subscribe@googlegroups.com>.
 Version ++2.52d (tbd):
 -----------------------------
 
+  - added never zero counters for afl-gcc and optional (because of an
+    optimization issue in llvm < 9) for llvm_mode (AFL_LLVM_NEVER_ZERO=1)
   - added whitelist support for llvm_mode via AFL_LLVM_WHITELIST to allow
     only to instrument what is actually interesting. Gives more speed and less
     map pollution (originally by choller@mozilla)
diff --git a/docs/env_variables.txt b/docs/env_variables.txt
index 725dc82e..f8c6c86a 100644
--- a/docs/env_variables.txt
+++ b/docs/env_variables.txt
@@ -108,8 +108,11 @@ Then there are a few specific features that are only available in llvm_mode:
 
   OTHER
   =====
-    - Setting AFL_NZERO_COUNTS=1 during compilation will use counters
-      that skip zero on overflow.
+    - Setting export AFL_LLVM_NOT_ZERO=1 during compilation will use counters
+      that skip zero on overflow. This is the default for llvm >= 9,
+      however for llvm versions below that this will increase an unnecessary
+      slowdown due a performance issue that is only fixed in llvm 9+.
+      This feature increases path discovery by a little bit.
 
 Note that AFL_INST_RATIO will behave a bit differently than for afl-gcc,
 because functions are *not* instrumented unconditionally - so low values