Merge branch 'master' into shared_memory_mmap_refactor

2025-06-08 16:21:32 +00:00 · 2019-07-14 20:02:20 +02:00 · 2019-07-14 20:02:20 +02:00 · da8e03e18a
commit da8e03e18a
parent 5c0830f628 4a80dbdd10
26 changed files with 5411 additions and 92 deletions
--- a/6
+++ b/6
@ -181,8 +181,8 @@ all_done: test_build
 .NOTPARALLEL: clean

 clean:
-	rm -f $(PROGS) afl-as as afl-g++ afl-clang afl-clang++ *.o *~ a.out core core.[1-9][0-9]* *.stackdump test .test .test1 .test2 test-instr .test-instr0 .test-instr1 qemu_mode/qemu-2.10.0.tar.bz2 afl-qemu-trace
-	rm -rf out_dir qemu_mode/qemu-2.10.0
+	rm -f $(PROGS) afl-as as afl-g++ afl-clang afl-clang++ *.o *~ a.out core core.[1-9][0-9]* *.stackdump test .test .test1 .test2 test-instr .test-instr0 .test-instr1 qemu_mode/qemu-3.1.0.tar.xz afl-qemu-trace
+	rm -rf out_dir qemu_mode/qemu-3.1.0
 	$(MAKE) -C llvm_mode clean
 	$(MAKE) -C libdislocator clean
 	$(MAKE) -C libtokencap clean
@ -194,7 +194,7 @@ install: all
 	rm -f $${DESTDIR}$(BIN_PATH)/afl-as
 	if [ -f afl-qemu-trace ]; then install -m 755 afl-qemu-trace $${DESTDIR}$(BIN_PATH); fi
 ifndef AFL_TRACE_PC
-	if [ -f afl-clang-fast -a -f afl-llvm-pass.so -a -f afl-llvm-rt.o ]; then set -e; install -m 755 afl-clang-fast $${DESTDIR}$(BIN_PATH); ln -sf afl-clang-fast $${DESTDIR}$(BIN_PATH)/afl-clang-fast++; install -m 755 afl-llvm-pass.so afl-llvm-rt.o $${DESTDIR}$(HELPER_PATH); fi
+	if [ -f afl-clang-fast -a -f libLLVMInsTrim.so -a -f afl-llvm-rt.o ]; then set -e; install -m 755 afl-clang-fast $${DESTDIR}$(BIN_PATH); ln -sf afl-clang-fast $${DESTDIR}$(BIN_PATH)/afl-clang-fast++; install -m 755 libLLVMInsTrim.so afl-llvm-rt.o $${DESTDIR}$(HELPER_PATH); fi
 else
 	if [ -f afl-clang-fast -a -f afl-llvm-rt.o ]; then set -e; install -m 755 afl-clang-fast $${DESTDIR}$(BIN_PATH); ln -sf afl-clang-fast $${DESTDIR}$(BIN_PATH)/afl-clang-fast++; install -m 755 afl-llvm-rt.o $${DESTDIR}$(HELPER_PATH); fi
 endif
--- a/afl-as.h
+++ b/afl-as.h
@ -189,6 +189,7 @@ static const u8* main_payload_32 =
  "  orb  $1, (%edx, %edi, 1)\n"
 #else
  "  incb (%edx, %edi, 1)\n"
+  "  adcb $0, (%edx, %edi, 1)\n" // never zero counter implementation. slightly better path discovery and little performance impact
 #endif /* ^SKIP_COUNTS */
  "\n"
  "__afl_return:\n"
@ -441,6 +442,7 @@ static const u8* main_payload_64 =
  "  orb  $1, (%rdx, %rcx, 1)\n"
 #else
  "  incb (%rdx, %rcx, 1)\n"
+  "  adcb $0, (%rdx, %rcx, 1)\n" // never zero counter implementation. slightly better path discovery and little performance impact
 #endif /* ^SKIP_COUNTS */
  "\n"
  "__afl_return:\n"
--- a/afl-fuzz.c
+++ b/afl-fuzz.c
--- a/alloc-inl.h
+++ b/alloc-inl.h
@ -76,6 +76,17 @@

 /* Sanity-checking macros for pointers. */

+#define CHECK_PTR(_p) do { \
+    if (_p) { \
+      if (ALLOC_C1(_p) ^ ALLOC_MAGIC_C1) {\
+        if (ALLOC_C1(_p) == ALLOC_MAGIC_F) \
+          ABORT("Use after free."); \
+        else ABORT("Corrupted head alloc canary."); \
+      } \
+   } \
+  } while (0)
+
+/*
 #define CHECK_PTR(_p) do { \
    if (_p) { \
      if (ALLOC_C1(_p) ^ ALLOC_MAGIC_C1) {\
@ -87,6 +98,7 @@
        ABORT("Corrupted tail alloc canary."); \
    } \
  } while (0)
+*/

 #define CHECK_PTR_EXPR(_p) ({ \
    typeof (_p) _tmp = (_p); \
--- a/config.h
+++ b/config.h
@ -83,6 +83,7 @@
   of 32-bit int overflows): */

 #define HAVOC_MAX_MULT      16
+#define HAVOC_MAX_MULT_MOPT 32

 /* Absolute minimum number of havoc cycles (after all adjustments): */

--- a/docs/ChangeLog
+++ b/docs/ChangeLog
@ -17,6 +17,10 @@ sending a mail to <afl-users+subscribe@googlegroups.com>.
 Version ++2.52d (tbd):
 -----------------------------

+  - added MOpt (github.com/puppet-meteor/MOpt-AFL) mode
+  - 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 a new doc about binary only fuzzing: docs/binaryonly_fuzzing.txt
  - more cpu power for afl-system-config
  - added forkserver patch to afl-tmin, makes it much faster (originally from
    github.com/nccgroup/TriforceAFL)
@ -27,9 +31,13 @@ Version ++2.52d (tbd):
    see docs/python_mutators.txt (originally by choller@mozilla)
  - added AFL_CAL_FAST for slow applications and AFL_DEBUG_CHILD_OUTPUT for
    debugging
+  - added -V time and -E execs option to better comparison runs, runs afl-fuzz
+    for a specific time/executions.
  - added a  -s seed  switch to allow afl run with a fixed initial
    seed that is not updated. this is good for performance and path discovery
    tests as the random numbers are deterministic then
+  - llvm_mode LAF_... env variables can now be specified as AFL_LLVM_LAF_...
+    that is longer but in line with other llvm specific env vars
  - ... your idea or patch?


--- a/docs/PATCHES
+++ b/docs/PATCHES
@ -17,10 +17,12 @@ afl-qemu-optimize-entrypoint.diff	by mh(at)mh-sec(dot)de
 afl-qemu-speed.diff			by abiondo on github
 afl-qemu-optimize-map.diff		by mh(at)mh-sec(dot)de

+ instrim (https://github.com/csienslab/instrim) was integrated
+ MOpt (github.com/puppet-meteor/MOpt-AFL) was imported
 + AFLfast additions (github.com/mboehme/aflfast) were incorporated.
 + Qemu 3.1 upgrade with enhancement patches (github.com/andreafioraldi/afl)
-+ Python mutator modules support (github.com/choeller/afl)
-+ Whitelisting in LLVM mode (github.com/choeller/afl)
+ Python mutator modules support (github.com/choller/afl)
+ Whitelisting in LLVM mode (github.com/choller/afl)
 + forkserver patch for afl-tmin (github.com/nccgroup/TriforceAFL)


--- a/docs/README
+++ b/docs/README
@ -2,27 +2,31 @@
 american fuzzy lop plus plus
 ============================

-  Written by Michal Zalewski <lcamtuf@google.com>
+  Originally written by Michal Zalewski <lcamtuf@google.com>

  Repository: https://github.com/vanhauser-thc/AFLplusplus

-  afl++ is maintained by Marc Heuse <mh@mh-sec.de> and Heiko Eissfeldt
-  <heiko.eissfeldt@hexco.de> as there have been no updates to afl since
-  November 2017.
+  afl++ is maintained by Marc Heuse <mh@mh-sec.de>, Heiko Eissfeldt
+  <heiko.eissfeldt@hexco.de> and Andrea Fioraldi as there have been no
+  updates to afl since November 2017.

-  This version has several bug fixes, new features and speed enhancements
-  based on community patches from https://github.com/vanhauser-thc/afl-patches
-  To see the list of which patches have been applied, see the PATCHES file.
+  Many improvements were made, e.g. more performant llvm_mode, supporting
+  llvm up to version 8, Qemu 3.1, more speed for Qemu, etc.

  Additionally AFLfast's power schedules by Marcel Boehme from
-  github.com/mboehme/aflfast have been incorporated.
+  https://github.com/mboehme/aflfast have been incorporated.

-  Plus it was upgraded to qemu 3.1 from 2.1 with the work of 
-  https://github.com/andreafioraldi/afl and got the community patches applied
-  to it.
+  C. Hollers afl-fuzz Python mutator module and llvm_mode whitelist support
+  was added too (https://github.com/choller/afl)

-  C. Hoellers afl-fuzz Python mutator module and llvm_mode whitelist support
-  was added too (https://github.com/choeller/afl)
+  New is the excellent MOpt mutator from
+  https://github.com/puppet-meteor/MOpt-AFL  
+
+  Also newly integrated is instrim, a very effective CFG llvm_mode
+  instrumentation implementation which replaced the original afl one and is
+  from https://github.com/csienslab/instrim
+
+  A more thorough list is available in the PATCHES file.

  So all in all this is the best-of AFL that is currently out there :-)

--- a/docs/README.MOpt
+++ b/docs/README.MOpt
@ -0,0 +1,43 @@
+# MOpt(imized) AFL by <puppet@zju.edu.cn>
+
+### 1. Description
+MOpt-AFL is a AFL-based fuzzer that utilizes a customized Particle Swarm
+Optimization (PSO) algorithm to find the optimal selection probability
+distribution of operators with respect to fuzzing effectiveness.
+More details can be found in the technical report.
+
+### 2. Cite Information
+Chenyang Lv, Shouling Ji, Chao Zhang, Yuwei Li, Wei-Han Lee, Yu Song and
+Raheem Beyah, MOPT: Optimized Mutation Scheduling for Fuzzers,
+USENIX Security 2019. 
+
+### 3. Seed Sets
+We open source all the seed sets used in the paper 
+"MOPT: Optimized Mutation Scheduling for Fuzzers".
+
+### 4. Experiment Results
+The experiment results can be found in 
+https://drive.google.com/drive/folders/184GOzkZGls1H2NuLuUfSp9gfqp1E2-lL?usp=sharing.  We only open source the crash files since the space is limited. 
+
+### 5. Technical Report
+MOpt_TechReport.pdf is the technical report of the paper 
+"MOPT: Optimized Mutation Scheduling for Fuzzers", which contains more deatails.
+
+### 6. Parameter Introduction
+Most important, you must add the parameter `-L` (e.g., `-L 0`) to launch the
+MOpt scheme. 
+<br>`-L` controls the time to move on to the pacemaker fuzzing mode.
+<br>`-L t:` when MOpt-AFL finishes the mutation of one input, if it has not
+discovered any new unique crash or path for more than t min, MOpt-AFL will
+enter the pacemaker fuzzing mode. 
+<br>Setting 0 will enter the pacemaker fuzzing mode at first, which is
+recommended in a short time-scale evaluation. 
+
+Other important parameters can be found in afl-fuzz.c, for instance, 
+<br>`swarm_num:` the number of the PSO swarms used in the fuzzing process.
+<br>`period_pilot:` how many times MOpt-AFL will execute the target program in the pilot fuzzing module, then it will enter the core fuzzing module. 
+<br>`period_core:` how many times MOpt-AFL will execute the target program in the core fuzzing module, then it will enter the PSO updating module. 
+<br>`limit_time_bound:` control how many interesting test cases need to be found before MOpt-AFL quits the pacemaker fuzzing mode and reuses the deterministic stage. 
+0 < `limit_time_bound` < 1, MOpt-AFL-tmp.  `limit_time_bound` >= 1, MOpt-AFL-ever. 
+
+Having fun with MOpt in AFL!
--- a/docs/binaryonly_fuzzing.txt
+++ b/docs/binaryonly_fuzzing.txt
@ -0,0 +1,115 @@
+
+Fuzzing binary-only programs with afl++
+=======================================
+
+afl++, libfuzzer and others are great if you have the source code, and
+it allows for very fast and coverage guided fuzzing.
+
+However, if there is only the binary program and not source code available,
+then standard afl++ (dumb mode) is not effective.
+
+The following is a description of how these can be fuzzed with afl++
+
+!!!!!
+DTLR: try DYNINST with afl-dyninst. If it produces too many crashes then
+      use afl -Q qemu_mode.
+!!!!!
+
+
+QEMU
+----
+Qemu is the "native" solution to the program.
+It is available in the ./qemu_mode/ directory and once compiled it can
+be accessed by the afl-fuzz -Q command line option.
+The speed decrease is at about 50%
+It the easiest to use alternative and even works for cross-platform binaries.
+
+As it is included in afl++ this needs no URL.
+
+
+DYNINST
+-------
+Dyninst is a binary instrumentation framework similar to Pintool and Dynamorio
+(see far below). Howver whereas Pintool and Dynamorio work at runtime, dyninst
+instruments the target at load time, and then let it run.
+This is great for some things, e.g. fuzzing, and not so effective for others,
+e.g. malware analysis.
+
+So what we can do with dyninst is taking every basic block, and put afl's
+instrumention code in there - and then save the binary.
+Afterwards we can just fuzz the newly saved target binary with afl-fuzz.
+Sounds great? It is. The issue though - this is a non-trivial problem to
+insert instructions, which changes addresses in the process space and that
+everything still works afterwards. Hence more often than not binaries
+crash when they are run.
+
+The speed decrease is about 15-35%, depending on the optimization options
+used with afl-dyninst.
+
+So if dyninst works, its the best option available. Otherwise it just doesn't
+work well.
+
+https://github.com/vanhauser-thc/afl-dyninst
+
+
+INTEL-PT
+--------
+The big issue with Intel's PT is the small buffer size and the complex
+encoding of the debug information collected through PT.
+This makes the decoding very CPU intensive and hence slow.
+As a result, the overall speed decrease is about 70-90% (depending on
+the implementation and other factors)
+
+there are two afl intel-pt implementations:
+
+1. https://github.com/junxzm1990/afl-pt
+ => this needs Ubuntu 14.04.05 without any updates and the 4.4 kernel.
+
+2. https://github.com/hunter-ht-2018/ptfuzzer
+ => this needs a 4.14 or 4.15 kernel. the "nopti" kernel boot option must
+    be used. This one is faster than the other.
+
+
+CORESIGHT
+---------
+
+Coresight is the ARM answer to Intel's PT.
+There is no implementation so far which handle coresight and getting
+it working on an ARM Linux is very difficult due custom kernel building
+on embedded systems is difficult. And finding one that has coresight in
+the ARM chip is difficult too.
+My guess is that it is slower than Qemu, but faster than Intel PT.
+If anyone finds any coresight implemention for afl please ping me:
+vh@thc.org
+
+
+PIN & DYNAMORIO
+---------------
+
+Pintool and Dynamorio are dynamic instrumentation engines, and they can be
+used for getting basic block information at runtime.
+Pintool is only available for Intel x32/x64 on Linux, Mac OS and Windows
+whereas Dynamorio is additionally available for ARM and AARCH64.
+Dynamorio is also 10x faster than Pintool.
+
+The big issue with Dynamorio (and therefore Pintool too) is speed.
+Dynamorio has a speed decrease of 98-99%
+Pintool has a speed decrease of 99.5%
+
+Hence Dynamorio is the option to go for if everything fails, and Pintool
+only if Dynamorio fails too.
+
+Dynamorio solutions:
+  https://github.com/vanhauser-thc/afl-dynamorio
+  https://github.com/mxmssh/drAFL
+  https://github.com/googleprojectzero/winafl/ <= very good but windows only
+
+Pintool solutions:
+  https://github.com/vanhauser-thc/afl-pin
+  https://github.com/mothran/aflpin
+  https://github.com/spinpx/afl_pin_mode  <= only old Pintool version supported
+
+
+That's it!
+News, corrections, updates?
+Email vh@thc.org
--- a/docs/env_variables.txt
+++ b/docs/env_variables.txt
@ -82,6 +82,9 @@ discussed in section #1, with the exception of:
  - TMPDIR and AFL_KEEP_ASSEMBLY, since no temporary assembly files are
    created.

+  - AFL_INST_RATIO, as we switched for instrim instrumentation which
+    is more effective but makes not much sense together with this option.
+
 Then there are a few specific features that are only available in llvm_mode:

  LAF-INTEL
@ -89,11 +92,11 @@ Then there are a few specific features that are only available in llvm_mode:
    This great feature will split compares to series of single byte comparisons
    to allow afl-fuzz to find otherwise rather impossible paths.

-    - Setting LAF_SPLIT_SWITCHES will split switch()es
+    - Setting AFL_LLVM_LAF_SPLIT_SWITCHES will split switch()es

-    - Setting LAF_TRANSFORM_COMPARES will split string compare functions
+    - Setting AFL_LLVM_LAF_TRANSFORM_COMPARES will split string compare functions

-    - Setting LAF_SPLIT_COMPARES will split > 8 bit CMP instructions
+    - Setting AFL_LLVM_LAF_SPLIT_COMPARES will split > 8 bit CMP instructions

    See llvm_mode/README.laf-intel for more information. 

@ -106,9 +109,17 @@ Then there are a few specific features that are only available in llvm_mode:

    See llvm_mode/README.whitelist for more information.

-Note that AFL_INST_RATIO will behave a bit differently than for afl-gcc,
-because functions are *not* instrumented unconditionally - so low values
-will have a more striking effect. For this tool, 0 is not a valid choice.
+  OTHER
+  =====
+    - Setting LOOPHEAD=1 optimized loops. afl-fuzz will only be able to
+      see the path the loop took, but not how many times it was called
+      (unless its a complex loop).
+
+    - Setting 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.

 3) Settings for afl-fuzz
 ------------------------
--- a/llvm_mode/LLVMInsTrim.so.cc
+++ b/llvm_mode/LLVMInsTrim.so.cc
@ -0,0 +1,350 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <unistd.h>
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/IPO/PassManagerBuilder.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/CFG.h"
+#include <unordered_set>
+#include <random>
+#include <list>
+#include <string>
+#include <fstream>
+
+#include "../config.h"
+#include "../debug.h"
+
+#include "MarkNodes.h"
+
+using namespace llvm;
+
+static cl::opt<bool> MarkSetOpt("markset", cl::desc("MarkSet"),
+                                cl::init(false));
+static cl::opt<bool> LoopHeadOpt("loophead", cl::desc("LoopHead"),
+                                 cl::init(false));
+
+namespace {
+  struct InsTrim : public ModulePass {
+
+  protected:
+    std::list<std::string> myWhitelist;
+
+  private:
+    std::mt19937 generator;
+    int total_instr = 0;
+
+    unsigned genLabel() {
+      return generator() % 65536;
+    }
+
+  public:
+    static char ID;
+    InsTrim() : ModulePass(ID), generator(0) {//}
+    
+//    AFLCoverage() : ModulePass(ID) {
+      char* instWhiteListFilename = getenv("AFL_LLVM_WHITELIST");
+      if (instWhiteListFilename) {
+        std::string line;
+        std::ifstream fileStream;
+        fileStream.open(instWhiteListFilename);
+        if (!fileStream)
+          report_fatal_error("Unable to open AFL_LLVM_WHITELIST");
+        getline(fileStream, line);
+        while (fileStream) {
+          myWhitelist.push_back(line);
+          getline(fileStream, line);
+        }
+      }
+    }
+
+    void getAnalysisUsage(AnalysisUsage &AU) const override {
+      AU.addRequired<DominatorTreeWrapperPass>();
+    }
+
+#if LLVM_VERSION_MAJOR < 4
+    const char *
+#else
+    StringRef
+#endif
+              getPassName() const override {
+      return "InstTrim Instrumentation";
+    }
+
+    bool runOnModule(Module &M) override {
+      char be_quiet = 0;
+      
+      if (isatty(2) && !getenv("AFL_QUIET")) {
+        SAYF(cCYA "LLVMInsTrim" VERSION cRST " by csienslab\n");
+      } else be_quiet = 1;
+    
+#if LLVM_VERSION_MAJOR < 9
+      char* neverZero_counters_str;
+      if ((neverZero_counters_str = getenv("AFL_LLVM_NOT_ZERO")) != NULL)
+        OKF("LLVM neverZero activated (by hexcoder)\n");
+#endif
+    
+      if (getenv("LOOPHEAD")) {
+        LoopHeadOpt = true;
+      }
+
+      // this is our default
+      MarkSetOpt = true;
+      
+/*    // I dont think this makes sense to port into LLVMInsTrim
+      char* inst_ratio_str = getenv("AFL_INST_RATIO");
+      unsigned int inst_ratio = 100;
+      if (inst_ratio_str) {
+       if (sscanf(inst_ratio_str, "%u", &inst_ratio) != 1 || !inst_ratio || inst_ratio > 100)
+         FATAL("Bad value of AFL_INST_RATIO (must be between 1 and 100)");
+      }
+*/
+
+      LLVMContext &C = M.getContext();
+      IntegerType *Int8Ty  = IntegerType::getInt8Ty(C);
+      IntegerType *Int32Ty = IntegerType::getInt32Ty(C);
+
+      GlobalVariable *CovMapPtr = new GlobalVariable(
+        M, PointerType::getUnqual(Int8Ty), false, GlobalValue::ExternalLinkage,
+        nullptr, "__afl_area_ptr");
+
+      GlobalVariable *OldPrev = new GlobalVariable(
+        M, Int32Ty, false, GlobalValue::ExternalLinkage, 0, "__afl_prev_loc",
+        0, GlobalVariable::GeneralDynamicTLSModel, 0, false);
+
+      u64 total_rs = 0;
+      u64 total_hs = 0;
+
+      for (Function &F : M) {
+        if (!F.size()) {
+          continue;
+        }
+
+        if (!myWhitelist.empty()) {
+          bool instrumentBlock = false;
+          DebugLoc Loc;
+          StringRef instFilename;
+
+          for (auto &BB : F) {
+            BasicBlock::iterator IP = BB.getFirstInsertionPt();
+            IRBuilder<> IRB(&(*IP));
+            if (!Loc)
+              Loc = IP->getDebugLoc();
+          }
+
+          if ( Loc ) {
+              DILocation *cDILoc = dyn_cast<DILocation>(Loc.getAsMDNode());
+
+              unsigned int instLine = cDILoc->getLine();
+              instFilename = cDILoc->getFilename();
+
+              if (instFilename.str().empty()) {
+                  /* If the original location is empty, try using the inlined location */
+                  DILocation *oDILoc = cDILoc->getInlinedAt();
+                  if (oDILoc) {
+                      instFilename = oDILoc->getFilename();
+                      instLine = oDILoc->getLine();
+                  }
+              }
+
+              /* Continue only if we know where we actually are */
+              if (!instFilename.str().empty()) {
+                  for (std::list<std::string>::iterator it = myWhitelist.begin(); it != myWhitelist.end(); ++it) {
+                      if (instFilename.str().length() >= it->length()) {
+                          if (instFilename.str().compare(instFilename.str().length() - it->length(), it->length(), *it) == 0) {
+                              instrumentBlock = true;
+                              break;
+                          }
+                      }
+                  }
+              }
+          }
+
+          /* Either we couldn't figure out our location or the location is
+           * not whitelisted, so we skip instrumentation. */
+          if (!instrumentBlock) {
+            if (!instFilename.str().empty())
+              SAYF(cYEL "[!] " cBRI "Not in whitelist, skipping %s ...\n", instFilename.str().c_str());
+            else
+              SAYF(cYEL "[!] " cBRI "No filename information found, skipping it");
+            continue;
+          }
+        }
+
+        std::unordered_set<BasicBlock *> MS;
+        if (!MarkSetOpt) {
+          for (auto &BB : F) {
+            MS.insert(&BB);
+          }
+          total_rs += F.size();
+        } else {
+          auto Result = markNodes(&F);
+          auto RS = Result.first;
+          auto HS = Result.second;
+
+          MS.insert(RS.begin(), RS.end());
+          if (!LoopHeadOpt) {
+            MS.insert(HS.begin(), HS.end());
+            total_rs += MS.size();
+          } else {
+            DenseSet<std::pair<BasicBlock *, BasicBlock *>> EdgeSet;
+            DominatorTreeWrapperPass *DTWP = &getAnalysis<DominatorTreeWrapperPass>(F);
+            auto DT = &DTWP->getDomTree();
+
+            total_rs += RS.size();
+            total_hs += HS.size();
+
+            for (BasicBlock *BB : HS) {
+              bool Inserted = false;
+              for (auto BI = pred_begin(BB), BE = pred_end(BB);
+                   BI != BE; ++BI
+              ) {
+                auto Edge = BasicBlockEdge(*BI, BB);
+                if (Edge.isSingleEdge() && DT->dominates(Edge, BB)) {
+                  EdgeSet.insert({*BI, BB});
+                  Inserted = true;
+                  break;
+                }
+              }
+              if (!Inserted) {
+                MS.insert(BB);
+                total_rs += 1;
+                total_hs -= 1;
+              }
+            }
+            for (auto I = EdgeSet.begin(), E = EdgeSet.end(); I != E; ++I) {
+              auto PredBB = I->first;
+              auto SuccBB = I->second;
+              auto NewBB = SplitBlockPredecessors(SuccBB, {PredBB}, ".split",
+                                                  DT, nullptr,
+#if LLVM_VERSION_MAJOR >= 8
+                                                  nullptr,
+#endif
+                                                  false);
+              MS.insert(NewBB);
+            }
+          }
+
+          auto *EBB = &F.getEntryBlock();
+          if (succ_begin(EBB) == succ_end(EBB)) {
+            MS.insert(EBB);
+            total_rs += 1;
+          }
+
+          for (BasicBlock &BB : F) {
+            if (MS.find(&BB) == MS.end()) {
+              continue;
+            }
+            IRBuilder<> IRB(&*BB.getFirstInsertionPt());
+            IRB.CreateStore(ConstantInt::get(Int32Ty, genLabel()), OldPrev);
+          }
+        }
+
+        for (BasicBlock &BB : F) {
+          auto PI = pred_begin(&BB);
+          auto PE = pred_end(&BB);
+          if (MarkSetOpt && MS.find(&BB) == MS.end()) {
+            continue;
+          }
+
+          IRBuilder<> IRB(&*BB.getFirstInsertionPt());
+          Value *L = NULL;
+          if (PI == PE) {
+            L = ConstantInt::get(Int32Ty, genLabel());
+          } else {
+            auto *PN = PHINode::Create(Int32Ty, 0, "", &*BB.begin());
+            DenseMap<BasicBlock *, unsigned> PredMap;
+            for (auto PI = pred_begin(&BB), PE = pred_end(&BB);
+                 PI != PE; ++PI
+            ) {
+              BasicBlock *PBB = *PI;
+              auto It = PredMap.insert({PBB, genLabel()});
+              unsigned Label = It.first->second;
+              PN->addIncoming(ConstantInt::get(Int32Ty, Label), PBB);
+            }
+            L = PN;
+          }
+
+          /* Load prev_loc */
+          LoadInst *PrevLoc = IRB.CreateLoad(OldPrev);
+          PrevLoc->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+          Value *PrevLocCasted = IRB.CreateZExt(PrevLoc, IRB.getInt32Ty());
+
+          /* Load SHM pointer */
+          LoadInst *MapPtr = IRB.CreateLoad(CovMapPtr);
+          MapPtr->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+          Value *MapPtrIdx = IRB.CreateGEP(MapPtr, IRB.CreateXor(PrevLocCasted, L));
+
+          /* Update bitmap */
+          LoadInst *Counter = IRB.CreateLoad(MapPtrIdx);
+          Counter->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+          
+          Value *Incr = IRB.CreateAdd(Counter, ConstantInt::get(Int8Ty, 1));
+
+#if LLVM_VERSION_MAJOR < 9
+          if (neverZero_counters_str != NULL) { // with llvm 9 we make this the default as the bug in llvm is then fixed
+#else
+  #warning "neverZero implementation needs to be reviewed!"
+#endif
+          /* hexcoder: Realize a counter that skips zero during overflow.
+           * Once this counter reaches its maximum value, it next increments to 1
+           *
+           * Instead of
+           * Counter + 1 -> Counter
+           * we inject now this
+           * Counter + 1 -> {Counter, OverflowFlag}
+           * Counter + OverflowFlag -> Counter
+           */
+            auto cf = IRB.CreateICmpEQ(Incr, ConstantInt::get(Int8Ty, 0));
+            auto carry = IRB.CreateZExt(cf, Int8Ty);
+            Incr = IRB.CreateAdd(Incr, carry);
+#if LLVM_VERSION_MAJOR < 9
+          }
+#endif
+   
+          IRB.CreateStore(Incr, MapPtrIdx)->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+   
+          /* Set prev_loc to cur_loc >> 1 */
+          /*
+          StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int32Ty, cur_loc >> 1), AFLPrevLoc);
+          Store->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+          */
+
+          total_instr++;
+        }
+      }
+
+      OKF("Instrumented %u locations (%llu, %llu) (%s mode)\n"/*", ratio %u%%)."*/,
+          total_instr, total_rs, total_hs,
+          getenv("AFL_HARDEN") ? "hardened" :
+          ((getenv("AFL_USE_ASAN") || getenv("AFL_USE_MSAN")) ?
+          "ASAN/MSAN" : "non-hardened")/*, inst_ratio*/);
+      return false;
+    }
+  }; // end of struct InsTrim
+}  // end of anonymous namespace
+
+char InsTrim::ID = 0;
+
+static void registerAFLPass(const PassManagerBuilder &,
+                            legacy::PassManagerBase &PM) {
+  PM.add(new InsTrim());
+}
+
+static RegisterStandardPasses RegisterAFLPass(
+    PassManagerBuilder::EP_OptimizerLast, registerAFLPass);
+
+static RegisterStandardPasses RegisterAFLPass0(
+    PassManagerBuilder::EP_EnabledOnOptLevel0, registerAFLPass);
--- a/llvm_mode/Makefile
+++ b/llvm_mode/Makefile
@ -27,13 +27,18 @@ VERSION     = $(shell grep '^\#define VERSION ' ../config.h | cut -d '"' -f2)

 LLVM_CONFIG ?= llvm-config
 LLVMVER  = $(shell $(LLVM_CONFIG) --version)
-#LLVM_OK = $(shell $(LLVM_CONFIG) --version | egrep -q '^[5-6]' && echo 0 || echo 1 )
-LLVM_UNSUPPORTED = $(shell echo $(LLVMVER) | egrep -q '^9|3.0' && echo 1 || echo 1 )
+LLVM_UNSUPPORTED = $(shell $(LLVM_CONFIG) --version | egrep -q '^9|3.0' && echo 1 || echo 0 )
+LLVM_MAJOR = ($shell $(LLVM_CONFIG) --version | sed 's/\..*//')

 ifeq "$(LLVM_UNSUPPORTED)" "1"
  $(warn llvm_mode only supports versions 3.8.0 up to 8.x )
 endif

+# this is not visible yet:
+ifeq "$(LLVM_MAJOR)" "9"
+  $(info llvm_mode deteted llvm 9, enabling neverZero implementation)
+endif
+
 CFLAGS      ?= -O3 -funroll-loops
 CFLAGS      += -Wall -D_FORTIFY_SOURCE=2 -g -Wno-pointer-sign \
               -DAFL_PATH=\"$(HELPER_PATH)\" -DBIN_PATH=\"$(BIN_PATH)\" \
@ -89,7 +94,7 @@ endif


 ifndef AFL_TRACE_PC
-  PROGS      = ../afl-clang-fast ../afl-llvm-pass.so ../afl-llvm-rt.o ../afl-llvm-rt-32.o ../afl-llvm-rt-64.o ../compare-transform-pass.so ../split-compares-pass.so ../split-switches-pass.so
+  PROGS      = ../afl-clang-fast ../libLLVMInsTrim.so ../afl-llvm-rt.o ../afl-llvm-rt-32.o ../afl-llvm-rt-64.o ../compare-transform-pass.so ../split-compares-pass.so ../split-switches-pass.so
 else
  PROGS      = ../afl-clang-fast ../afl-llvm-rt.o ../afl-llvm-rt-32.o ../afl-llvm-rt-64.o ../compare-transform-pass.so ../split-compares-pass.so ../split-switches-pass.so
 endif
@ -140,8 +145,8 @@ endif
 	$(CC) $(CFLAGS) $< -o $@ $(LDFLAGS)
 	ln -sf afl-clang-fast ../afl-clang-fast++

-../afl-llvm-pass.so: afl-llvm-pass.so.cc | test_deps
-	$(CXX) $(CLANG_CFL) -shared $< -o $@ $(CLANG_LFL)
+../libLLVMInsTrim.so: LLVMInsTrim.so.cc MarkNodes.cc | test_deps
+	$(CXX) $(CLANG_CFL) -DLLVMInsTrim_EXPORTS -fno-rtti -fPIC -std=gnu++11 -shared $< MarkNodes.cc -o $@ $(CLANG_LFL)

 # laf
 ../split-switches-pass.so:	split-switches-pass.so.cc | test_deps
@ -165,7 +170,7 @@ endif

 test_build: $(PROGS)
 	@echo "[*] Testing the CC wrapper and instrumentation output..."
-	unset AFL_USE_ASAN AFL_USE_MSAN AFL_INST_RATIO; AFL_QUIET=1 AFL_PATH=. AFL_CC=$(CC) LAF_SPLIT_SWITCHES=1 LAF_TRANSFORM_COMPARES=1 LAF_SPLIT_COMPARES=1 ../afl-clang-fast $(CFLAGS) ../test-instr.c -o test-instr $(LDFLAGS)
+	unset AFL_USE_ASAN AFL_USE_MSAN AFL_INST_RATIO; AFL_QUIET=1 AFL_PATH=. AFL_CC=$(CC) AFL_LLVM_LAF_SPLIT_SWITCHES=1 AFL_LLVM_LAF_TRANSFORM_COMPARES=1 AFL_LLVM_LAF_SPLIT_COMPARES=1 ../afl-clang-fast $(CFLAGS) ../test-instr.c -o test-instr $(LDFLAGS)
 	echo 0 | ../afl-showmap -m none -q -o .test-instr0 ./test-instr
 	echo 1 | ../afl-showmap -m none -q -o .test-instr1 ./test-instr
 	@rm -f test-instr
--- a/llvm_mode/MarkNodes.cc
+++ b/llvm_mode/MarkNodes.cc
@ -0,0 +1,355 @@
+#include <algorithm>
+#include <map>
+#include <queue>
+#include <set>
+#include <vector>
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+DenseMap<BasicBlock *, uint32_t> LMap;
+std::vector<BasicBlock *> Blocks;
+std::set<uint32_t> Marked , Markabove;
+std::vector< std::vector<uint32_t> > Succs , Preds;
+
+void reset(){
+  LMap.clear();
+  Blocks.clear();
+  Marked.clear();
+  Markabove.clear();
+}
+
+uint32_t start_point;
+
+void labelEachBlock(Function *F) {
+  // Fake single endpoint;
+  LMap[NULL] = Blocks.size();
+  Blocks.push_back(NULL);
+ 
+  // Assign the unique LabelID to each block;
+  for (auto I = F->begin(), E = F->end(); I != E; ++I) {
+    BasicBlock *BB = &*I;
+    LMap[BB] = Blocks.size();
+    Blocks.push_back(BB);
+  }
+  
+  start_point = LMap[&F->getEntryBlock()];
+}
+
+void buildCFG(Function *F) {
+  Succs.resize( Blocks.size() );
+  Preds.resize( Blocks.size() );
+  for( size_t i = 0 ; i < Succs.size() ; i ++ ){
+    Succs[ i ].clear();
+    Preds[ i ].clear();
+  }
+
+  //uint32_t FakeID = 0;
+  for (auto S = F->begin(), E = F->end(); S != E; ++S) {
+    BasicBlock *BB = &*S;
+    uint32_t MyID = LMap[BB];
+    //if (succ_begin(BB) == succ_end(BB)) {
+      //Succs[MyID].push_back(FakeID);
+      //Marked.insert(MyID);
+    //}
+    for (auto I = succ_begin(BB), E = succ_end(BB); I != E; ++I) {
+      Succs[MyID].push_back(LMap[*I]);
+    }
+  }
+}
+
+std::vector< std::vector<uint32_t> > tSuccs;
+std::vector<bool> tag , indfs;
+
+void DFStree(size_t now_id) {
+  if(tag[now_id]) return;
+  tag[now_id]=true;
+  indfs[now_id]=true;
+  for (auto succ: tSuccs[now_id]) {
+    if(tag[succ] and indfs[succ]) {
+      Marked.insert(succ);
+      Markabove.insert(succ);
+      continue;
+    }
+    Succs[now_id].push_back(succ);
+    Preds[succ].push_back(now_id);
+    DFStree(succ);
+  }
+  indfs[now_id]=false;
+}
+void turnCFGintoDAG(Function *F) {
+  tSuccs = Succs;
+  tag.resize(Blocks.size());
+  indfs.resize(Blocks.size());
+  for (size_t i = 0; i < Blocks.size(); ++ i) {
+    Succs[i].clear();
+    tag[i]=false;
+    indfs[i]=false;
+  }
+  DFStree(start_point);
+  for (size_t i = 0; i < Blocks.size(); ++ i) 
+    if( Succs[i].empty() ){
+      Succs[i].push_back(0);
+      Preds[0].push_back(i);
+    }
+}
+
+uint32_t timeStamp;
+namespace DominatorTree{
+  std::vector< std::vector<uint32_t> > cov;
+  std::vector<uint32_t> dfn, nfd, par, sdom, idom, mom, mn;
+
+  bool Compare(uint32_t u, uint32_t v) {
+    return dfn[u] < dfn[v];
+  }
+  uint32_t eval(uint32_t u) {
+    if( mom[u] == u ) return u;
+    uint32_t res = eval( mom[u] );
+    if(Compare(sdom[mn[mom[u]]] , sdom[mn[u]])) {
+      mn[u] = mn[mom[u]];
+    }
+    return mom[u] = res;
+  }
+
+  void DFS(uint32_t now) {
+    timeStamp += 1;
+    dfn[now] = timeStamp;
+    nfd[timeStamp - 1] = now;
+    for( auto succ : Succs[now] ) {
+      if( dfn[succ] == 0 ) {
+        par[succ] = now;
+        DFS(succ);
+      }
+    }
+  }
+
+  void DominatorTree(Function *F) {
+    if( Blocks.empty() ) return;
+    uint32_t s = start_point;
+
+    // Initialization
+    mn.resize(Blocks.size());
+    cov.resize(Blocks.size());
+    dfn.resize(Blocks.size());
+    nfd.resize(Blocks.size());
+    par.resize(Blocks.size());
+    mom.resize(Blocks.size());
+    sdom.resize(Blocks.size());
+    idom.resize(Blocks.size());
+
+    for( uint32_t i = 0 ; i < Blocks.size() ; i ++ ) {
+      dfn[i] = 0;
+      nfd[i] = Blocks.size();
+      cov[i].clear();
+      idom[i] = mom[i] = mn[i] = sdom[i] = i;
+    }
+
+    timeStamp = 0;
+    DFS(s);
+
+    for( uint32_t i = Blocks.size() - 1 ; i >= 1u ; i -- ) {
+      uint32_t now = nfd[i];
+      if( now == Blocks.size() ) {
+        continue;
+      }
+      for( uint32_t pre : Preds[ now ] ) {
+        if( dfn[ pre ] ) {
+          eval(pre);
+          if( Compare(sdom[mn[pre]], sdom[now]) ) {
+            sdom[now] = sdom[mn[pre]];
+          }
+        }
+      }
+      cov[sdom[now]].push_back(now);
+      mom[now] = par[now];
+      for( uint32_t x : cov[par[now]] ) {
+        eval(x);
+        if( Compare(sdom[mn[x]], par[now]) ) {
+          idom[x] = mn[x];
+        } else {
+          idom[x] = par[now];
+        }
+      }
+    }
+
+    for( uint32_t i = 1 ; i < Blocks.size() ; i += 1 ) {
+      uint32_t now = nfd[i];
+      if( now == Blocks.size() ) {
+        continue;
+      }
+      if(idom[now] != sdom[now])
+        idom[now] = idom[idom[now]];
+    }
+  }
+}; // End of DominatorTree
+
+std::vector<uint32_t> Visited, InStack;
+std::vector<uint32_t> TopoOrder, InDeg;
+std::vector< std::vector<uint32_t> > t_Succ , t_Pred;
+
+void Go(uint32_t now, uint32_t tt) {
+  if( now == tt ) return;
+  Visited[now] = InStack[now] = timeStamp;
+
+  for(uint32_t nxt : Succs[now]) {
+    if(Visited[nxt] == timeStamp and InStack[nxt] == timeStamp) {
+      Marked.insert(nxt);
+    }
+    t_Succ[now].push_back(nxt);
+    t_Pred[nxt].push_back(now);
+    InDeg[nxt] += 1;
+    if(Visited[nxt] == timeStamp) {
+      continue;
+    }
+    Go(nxt, tt);
+  }
+
+  InStack[now] = 0;
+}
+
+void TopologicalSort(uint32_t ss, uint32_t tt) {
+  timeStamp += 1;
+
+  Go(ss, tt);
+
+  TopoOrder.clear();
+  std::queue<uint32_t> wait;
+  wait.push(ss);
+  while( not wait.empty() ) {
+    uint32_t now = wait.front(); wait.pop();
+    TopoOrder.push_back(now);
+    for(uint32_t nxt : t_Succ[now]) {
+      InDeg[nxt] -= 1;
+      if(InDeg[nxt] == 0u) {
+        wait.push(nxt);
+      }
+    }
+  }
+}
+
+std::vector< std::set<uint32_t> > NextMarked;
+bool Indistinguish(uint32_t node1, uint32_t node2) {
+  if(NextMarked[node1].size() > NextMarked[node2].size()){
+    uint32_t _swap = node1;
+    node1 = node2;
+    node2 = _swap;
+  }
+  for(uint32_t x : NextMarked[node1]) {
+    if( NextMarked[node2].find(x) != NextMarked[node2].end() ) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void MakeUniq(uint32_t now) {
+  bool StopFlag = false;
+  if (Marked.find(now) == Marked.end()) {
+    for(uint32_t pred1 : t_Pred[now]) {
+      for(uint32_t pred2 : t_Pred[now]) {
+        if(pred1 == pred2) continue;
+        if(Indistinguish(pred1, pred2)) {
+          Marked.insert(now);
+          StopFlag = true;
+          break;
+        }
+      }
+      if (StopFlag) {
+        break;
+      }
+    }
+  }
+  if(Marked.find(now) != Marked.end()) {
+    NextMarked[now].insert(now);
+  } else {
+    for(uint32_t pred : t_Pred[now]) {
+      for(uint32_t x : NextMarked[pred]) {
+        NextMarked[now].insert(x);
+      }
+    }
+  }
+}
+
+void MarkSubGraph(uint32_t ss, uint32_t tt) {
+  TopologicalSort(ss, tt);
+  if(TopoOrder.empty()) return;
+
+  for(uint32_t i : TopoOrder) {
+    NextMarked[i].clear();
+  }
+
+  NextMarked[TopoOrder[0]].insert(TopoOrder[0]);
+  for(uint32_t i = 1 ; i < TopoOrder.size() ; i += 1) {
+    MakeUniq(TopoOrder[i]);
+  }
+}
+
+void MarkVertice(Function *F) {
+  uint32_t s = start_point;
+
+  InDeg.resize(Blocks.size());
+  Visited.resize(Blocks.size());
+  InStack.resize(Blocks.size());
+  t_Succ.resize(Blocks.size());
+  t_Pred.resize(Blocks.size());
+  NextMarked.resize(Blocks.size());
+
+  for( uint32_t i = 0 ; i < Blocks.size() ; i += 1 ) {
+    Visited[i] = InStack[i] = InDeg[i] = 0;
+    t_Succ[i].clear();
+    t_Pred[i].clear();
+  }
+  timeStamp = 0;
+  uint32_t t = 0;
+  //MarkSubGraph(s, t);
+  //return;
+
+  while( s != t ) {
+    MarkSubGraph(DominatorTree::idom[t], t);
+    t = DominatorTree::idom[t];
+  }
+
+}
+
+// return {marked nodes}
+std::pair<std::vector<BasicBlock *>,
+          std::vector<BasicBlock *> >markNodes(Function *F) {
+  assert(F->size() > 0 && "Function can not be empty");
+
+  reset();
+  labelEachBlock(F);
+  buildCFG(F);
+  turnCFGintoDAG(F);
+  DominatorTree::DominatorTree(F);
+  MarkVertice(F);
+
+  std::vector<BasicBlock *> Result , ResultAbove;
+  for( uint32_t x : Markabove ) {
+    auto it = Marked.find( x );
+    if( it != Marked.end() )
+      Marked.erase( it );
+    if( x )
+      ResultAbove.push_back(Blocks[x]);
+  }
+  for( uint32_t x : Marked ) {
+    if (x == 0) {
+      continue;
+    } else {
+      Result.push_back(Blocks[x]);
+    }
+  }
+
+  return { Result , ResultAbove };
+}
--- a/llvm_mode/MarkNodes.h
+++ b/llvm_mode/MarkNodes.h
@ -0,0 +1,11 @@
+#ifndef __MARK_NODES__
+#define __MARK_NODES__
+
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Function.h"
+#include<vector>
+
+std::pair<std::vector<llvm::BasicBlock *>,
+          std::vector<llvm::BasicBlock *>> markNodes(llvm::Function *F);
+
+#endif
--- a/llvm_mode/README.laf-intel
+++ b/llvm_mode/README.laf-intel
@ -8,13 +8,13 @@ compile the target project.

 The following options exist:

-export LAF_SPLIT_SWITCHES=1     Enables the split-switches pass.
+export AFL_LLVM_LAF_SPLIT_SWITCHES=1     Enables the split-switches pass.

-export LAF_TRANSFORM_COMPARES=1 Enables the transform-compares pass
+export AFL_LLVM_LAF_TRANSFORM_COMPARES=1 Enables the transform-compares pass
                             (strcmp, memcmp, strncmp, strcasecmp, strncasecmp).

-export LAF_SPLIT_COMPARES=1     Enables the split-compares pass.
+export AFL_LLVM_LAF_SPLIT_COMPARES=1     Enables the split-compares pass.
      By default it will split all compares with a bit width <= 64 bits.
      You can change this behaviour by setting 
-          export LAF_SPLIT_COMPARES_BITW=<bit_width>.
+          export AFL_LLVM_LAF_SPLIT_COMPARES_BITW=<bit_width>.

--- a/llvm_mode/README.llvm
+++ b/llvm_mode/README.llvm
@ -38,8 +38,8 @@ co-exists with the original code.

 The idea and much of the implementation comes from Laszlo Szekeres.

-2) How to use
-------------
+2) How to use this
+------------------

 In order to leverage this mechanism, you need to have clang installed on your
 system. You should also make sure that the llvm-config tool is in your path
@ -69,20 +69,41 @@ operating mode of AFL, e.g.:
 Be sure to also include CXX set to afl-clang-fast++ for C++ code.

 The tool honors roughly the same environmental variables as afl-gcc (see
-../docs/env_variables.txt). This includes AFL_INST_RATIO, AFL_USE_ASAN,
-AFL_HARDEN, and AFL_DONT_OPTIMIZE.
+../docs/env_variables.txt). This includes AFL_USE_ASAN,
+AFL_HARDEN, and AFL_DONT_OPTIMIZE. However AFL_INST_RATIO is not honored
+as it does not serve a good purpose with the more effective instrim CFG
+analysis.

 Note: if you want the LLVM helper to be installed on your system for all
 users, you need to build it before issuing 'make install' in the parent
 directory.

-3) Gotchas, feedback, bugs
+3) Options
+
+Several options are present to make llvm_mode faster or help it rearrange
+the code to make afl-fuzz path discovery easier.
+
+If you need just to instrument specific parts of the code, you can whitelist
+which C/C++ files to actually intrument. See README.whitelist
+
+For splitting memcmp, strncmp, etc. please see README.laf-intel
+
+As the original afl llvm_mode implementation has been replaced with
+then much more effective instrim (https://github.com/csienslab/instrim/) 
+there is an option for optimizing loops. This optimization shows which
+part of the loop has been selected, but not how many time a loop has been
+called in a row (unless its a complex loop and a block inside was
+instrumented). If you want to enable this set the environment variable
+LOOPHEAD=1
+
+
+4) Gotchas, feedback, bugs
 --------------------------

 This is an early-stage mechanism, so field reports are welcome. You can send bug
 reports to <afl-users@googlegroups.com>.

-4) Bonus feature #1: deferred instrumentation
+5) Bonus feature #1: deferred instrumentation
 ---------------------------------------------

 AFL tries to optimize performance by executing the targeted binary just once,
@ -129,7 +150,7 @@ will keep working normally when compiled with a tool other than afl-clang-fast.
 Finally, recompile the program with afl-clang-fast (afl-gcc or afl-clang will
 *not* generate a deferred-initialization binary) - and you should be all set!

-5) Bonus feature #2: persistent mode
+6) Bonus feature #2: persistent mode
 ------------------------------------

 Some libraries provide APIs that are stateless, or whose state can be reset in
@ -169,7 +190,7 @@ PS. Because there are task switches still involved, the mode isn't as fast as
 faster than the normal fork() model, and compared to in-process fuzzing,
 should be a lot more robust.

-6) Bonus feature #3: new 'trace-pc-guard' mode
+8) Bonus feature #3: new 'trace-pc-guard' mode
 ----------------------------------------------

 Recent versions of LLVM are shipping with a built-in execution tracing feature
--- a/llvm_mode/README.neverzero
+++ b/llvm_mode/README.neverzero
@ -0,0 +1,22 @@
+Usage
+=====
+
+In larger, complex or reiterative programs the map that collects the edge pairs
+can easily fill up and wrap.
+This is not that much of an issue - unless by chance it wraps just to a 0
+when the program execution ends.
+In this case afl-fuzz is not able to see that the pair has been accessed and
+will ignore it.
+
+NeverZero prevents this behaviour. If a counter wraps, it jumps over the 0
+directly to a 1. This improves path discovery (by a very little amount)
+at a very little cost (one instruction per edge).
+
+This is implemented in afl-gcc, however for llvm_mode this is optional if
+the llvm version is below 9 - as there is a perfomance bug that is only fixed
+in version 9 and onwards.
+
+If you want to enable this for llvm < 9 then set
+
+export AFL_LLVM_NOT_ZERO=1
+
--- a/llvm_mode/afl-clang-fast.c
+++ b/llvm_mode/afl-clang-fast.c
@ -32,6 +32,7 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
+#include <assert.h>

 static u8*  obj_path;               /* Path to runtime libraries         */
 static u8** cc_params;              /* Parameters passed to the real CC  */
@ -87,7 +88,7 @@ static void find_obj(u8* argv0) {
    return;
  }

-  FATAL("Unable to find 'afl-llvm-rt.o' or 'afl-llvm-pass.so'. Please set AFL_PATH");
+  FATAL("Unable to find 'afl-llvm-rt.o' or 'libLLVMInsTrim.so'. Please set AFL_PATH");
 
 }

@ -113,28 +114,28 @@ static void edit_params(u32 argc, char** argv) {
  }

  /* There are two ways to compile afl-clang-fast. In the traditional mode, we
-     use afl-llvm-pass.so to inject instrumentation. In the experimental
+     use libLLVMInsTrim.so to inject instrumentation. In the experimental
     'trace-pc-guard' mode, we use native LLVM instrumentation callbacks
     instead. The latter is a very recent addition - see:

     http://clang.llvm.org/docs/SanitizerCoverage.html#tracing-pcs-with-guards */

  // laf
-  if (getenv("LAF_SPLIT_SWITCHES")) {
+  if (getenv("LAF_SPLIT_SWITCHES")||getenv("AFL_LLVM_LAF_SPLIT_SWITCHES")) {
    cc_params[cc_par_cnt++] = "-Xclang";
    cc_params[cc_par_cnt++] = "-load";
    cc_params[cc_par_cnt++] = "-Xclang";
    cc_params[cc_par_cnt++] = alloc_printf("%s/split-switches-pass.so", obj_path);
  }

-  if (getenv("LAF_TRANSFORM_COMPARES")) {
+  if (getenv("LAF_TRANSFORM_COMPARES")||getenv("AFL_LLVM_LAF_TRANSFORM_COMPARES")) {
    cc_params[cc_par_cnt++] = "-Xclang";
    cc_params[cc_par_cnt++] = "-load";
    cc_params[cc_par_cnt++] = "-Xclang";
    cc_params[cc_par_cnt++] = alloc_printf("%s/compare-transform-pass.so", obj_path);
  }

-  if (getenv("LAF_SPLIT_COMPARES")) {
+  if (getenv("LAF_SPLIT_COMPARES")||getenv("AFL_LLVM_LAF_SPLIT_COMPARES")) {
    cc_params[cc_par_cnt++] = "-Xclang";
    cc_params[cc_par_cnt++] = "-load";
    cc_params[cc_par_cnt++] = "-Xclang";
@ -150,7 +151,8 @@ static void edit_params(u32 argc, char** argv) {
  cc_params[cc_par_cnt++] = "-Xclang";
  cc_params[cc_par_cnt++] = "-load";
  cc_params[cc_par_cnt++] = "-Xclang";
-  cc_params[cc_par_cnt++] = alloc_printf("%s/afl-llvm-pass.so", obj_path);
+  cc_params[cc_par_cnt++] = alloc_printf("%s/libLLVMInsTrim.so", obj_path);
+//  cc_params[cc_par_cnt++] = alloc_printf("%s/afl-llvm-pass.so", obj_path);
 #endif /* ^USE_TRACE_PC */

  cc_params[cc_par_cnt++] = "-Qunused-arguments";
--- a/llvm_mode/afl-llvm-pass.so.cc
+++ b/llvm_mode/afl-llvm-pass.so.cc
@ -118,6 +118,10 @@ bool AFLCoverage::runOnModule(Module &M) {

  }

+#if LLVM_VERSION_MAJOR < 9
+  char* neverZero_counters_str = getenv("AFL_LLVM_NOT_ZERO");
+#endif
+
  /* Get globals for the SHM region and the previous location. Note that
     __afl_prev_loc is thread-local. */

@ -227,21 +231,69 @@ bool AFLCoverage::runOnModule(Module &M) {

      LoadInst *MapPtr = IRB.CreateLoad(AFLMapPtr);
      MapPtr->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
-      Value *MapPtrIdx =
-          IRB.CreateGEP(MapPtr, IRB.CreateXor(PrevLocCasted, CurLoc));
+      Value *MapPtrIdx = IRB.CreateGEP(MapPtr, IRB.CreateXor(PrevLocCasted, CurLoc));

      /* Update bitmap */

      LoadInst *Counter = IRB.CreateLoad(MapPtrIdx);
      Counter->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+
      Value *Incr = IRB.CreateAdd(Counter, ConstantInt::get(Int8Ty, 1));
-      IRB.CreateStore(Incr, MapPtrIdx)
-          ->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+
+#if LLVM_VERSION_MAJOR < 9
+      if (neverZero_counters_str != NULL) { // with llvm 9 we make this the default as the bug in llvm is then fixed
+#endif
+        /* hexcoder: Realize a counter that skips zero during overflow.
+         * Once this counter reaches its maximum value, it next increments to 1
+         *
+         * Instead of
+         * Counter + 1 -> Counter
+         * we inject now this
+         * Counter + 1 -> {Counter, OverflowFlag}
+         * Counter + OverflowFlag -> Counter
+         */
+/*       // we keep the old solutions just in case
+         // Solution #1
+         if (neverZero_counters_str[0] == '1') {
+           CallInst *AddOv = IRB.CreateBinaryIntrinsic(Intrinsic::uadd_with_overflow, Counter, ConstantInt::get(Int8Ty, 1));
+           AddOv->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));
+           Value *SumWithOverflowBit = AddOv;
+           Incr = IRB.CreateAdd(IRB.CreateExtractValue(SumWithOverflowBit, 0),  // sum 
+                                IRB.CreateZExt( // convert from one bit type to 8 bits type 
+                                               IRB.CreateExtractValue(SumWithOverflowBit, 1), // overflow
+                                               Int8Ty));
+          // Solution #2
+          } else if (neverZero_counters_str[0] == '2') {
+             auto cf = IRB.CreateICmpEQ(Counter, ConstantInt::get(Int8Ty, 255));
+             Value *HowMuch = IRB.CreateAdd(ConstantInt::get(Int8Ty, 1), cf);
+             Incr = IRB.CreateAdd(Counter, HowMuch);
+          // Solution #3
+          } else if (neverZero_counters_str[0] == '3') {
+*/
+          // this is the solution we choose because llvm9 should do the right thing here
+            auto cf = IRB.CreateICmpEQ(Incr, ConstantInt::get(Int8Ty, 0));
+            auto carry = IRB.CreateZExt(cf, Int8Ty);
+            Incr = IRB.CreateAdd(Incr, carry);
+/*
+         // Solution #4
+         } else if (neverZero_counters_str[0] == '4') {
+            auto cf = IRB.CreateICmpULT(Incr, ConstantInt::get(Int8Ty, 1));
+            auto carry = IRB.CreateZExt(cf, Int8Ty);
+            Incr = IRB.CreateAdd(Incr, carry);
+         } else {
+            fprintf(stderr, "Error: unknown value for AFL_NZERO_COUNTS: %s (valid is 1-4)\n", neverZero_counters_str);
+            exit(-1);
+         }
+*/
+#if LLVM_VERSION_MAJOR < 9
+      }
+#endif
+
+      IRB.CreateStore(Incr, MapPtrIdx)->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));

      /* Set prev_loc to cur_loc >> 1 */

-      StoreInst *Store =
-          IRB.CreateStore(ConstantInt::get(Int32Ty, cur_loc >> 1), AFLPrevLoc);
+      StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int32Ty, cur_loc >> 1), AFLPrevLoc);
      Store->setMetadata(M.getMDKindID("nosanitize"), MDNode::get(C, None));

      inst_blocks++;
--- a/llvm_mode/compare-transform-pass.so.cc
+++ b/llvm_mode/compare-transform-pass.so.cc
@ -304,6 +304,7 @@ bool CompareTransform::transformCmps(Module &M, const bool processStrcmp, const

 bool CompareTransform::runOnModule(Module &M) {

+  if (getenv("AFL_QUIET") == NULL)
    llvm::errs() << "Running compare-transform-pass by laf.intel@gmail.com, extended by heiko@hexco.de\n";
  transformCmps(M, true, true, true, true, true);
  verifyModule(M);
--- a/llvm_mode/split-compares-pass.so.cc
+++ b/llvm_mode/split-compares-pass.so.cc
@ -477,6 +477,8 @@ bool SplitComparesTransform::runOnModule(Module &M) {
  int bitw = 64;

  char* bitw_env = getenv("LAF_SPLIT_COMPARES_BITW");
+  if (!bitw_env)
+    bitw_env = getenv("AFL_LLVM_LAF_SPLIT_COMPARES_BITW");
  if (bitw_env) {
    bitw = atoi(bitw_env);
  }
@ -485,6 +487,7 @@ bool SplitComparesTransform::runOnModule(Module &M) {

  simplifySignedness(M);

+  if (getenv("AFL_QUIET") == NULL)
    errs() << "Split-compare-pass by laf.intel@gmail.com\n"; 

  switch (bitw) {
--- a/llvm_mode/split-switches-pass.so.cc
+++ b/llvm_mode/split-switches-pass.so.cc
@ -244,6 +244,7 @@ bool SplitSwitchesTransform::splitSwitches(Module &M) {

    /* If there is only the default destination or the condition checks 8 bit or less, don't bother with the code below. */
    if (!SI->getNumCases() || bitw <= 8) {
+      if (getenv("AFL_QUIET") == NULL)
        errs() << "skip trivial switch..\n";
      continue;
    }
@ -302,6 +303,7 @@ bool SplitSwitchesTransform::splitSwitches(Module &M) {

 bool SplitSwitchesTransform::runOnModule(Module &M) {

+  if (getenv("AFL_QUIET") == NULL)
    llvm::errs() << "Running split-switches-pass by laf.intel@gmail.com\n"; 
  splitSwitches(M);
  verifyModule(M);
--- a/python_mutators/README
+++ b/python_mutators/README
@ -9,3 +9,7 @@ simple-chunk-replace.py - this is a simple example where chunks are replaced

 common.py 	- this can be used for common functions and helpers.
 		  the examples do not use this though. But you can :)
+
+wrapper_afl_min.py - mutation of XML documents, loads XmlMutatorMin.py
+
+XmlMutatorMin.py - module for XML mutation
--- a/python_mutators/XmlMutatorMin.py
+++ b/python_mutators/XmlMutatorMin.py
@ -0,0 +1,331 @@
+#!/usr/bin/python
+
+""" Mutation of XML documents, should be called from one of its wrappers (CLI, AFL, ...) """
+
+from __future__ import print_function
+from copy import deepcopy
+from lxml import etree as ET
+import random, re, io
+
+###########################
+# The XmlMutatorMin class #
+###########################
+
+class XmlMutatorMin:
+
+    """
+        Optionals parameters:
+            seed        Seed used by the PRNG (default: "RANDOM")
+            verbose     Verbosity (default: False)
+    """
+
+    def __init__(self, seed="RANDOM", verbose=False):
+
+        """ Initialize seed, database and mutators """
+
+        # Verbosity
+        self.verbose = verbose
+
+        # Initialize PRNG
+        self.seed = str(seed)
+        if self.seed == "RANDOM":
+            random.seed()
+        else:
+            if self.verbose:
+                print("Static seed '%s'" % self.seed)
+            random.seed(self.seed)
+
+        # Initialize input and output documents
+        self.input_tree = None
+        self.tree = None
+
+        # High-level mutators (no database needed)
+        hl_mutators_delete = [ "del_node_and_children", "del_node_but_children", "del_attribute", "del_content" ] # Delete items
+        hl_mutators_fuzz = ["fuzz_attribute"] # Randomly change attribute values
+
+        # Exposed mutators
+        self.hl_mutators_all = hl_mutators_fuzz + hl_mutators_delete
+        
+    def __parse_xml (self, xml):
+
+        """ Parse an XML string. Basic wrapper around lxml.parse() """
+
+        try:
+            # Function parse() takes care of comments / DTD / processing instructions / ...
+        	tree = ET.parse(io.BytesIO(xml))
+        except ET.ParseError:
+            raise RuntimeError("XML isn't well-formed!")
+        except LookupError as e:
+            raise RuntimeError(e)
+
+        # Return a document wrapper
+        return tree
+
+    def __exec_among (self, module, functions, min_times, max_times):
+
+        """ Randomly execute $functions between $min and $max times """
+
+        for i in xrange (random.randint (min_times, max_times)):
+            # Function names are mangled because they are "private"
+            getattr (module, "_XmlMutatorMin__" + random.choice(functions)) ()
+
+    def __serialize_xml (self, tree):
+
+        """ Serialize a XML document. Basic wrapper around lxml.tostring() """
+
+        return ET.tostring(tree, with_tail=False, xml_declaration=True, encoding=tree.docinfo.encoding)
+
+    def __ver (self, version):
+
+        """ Helper for displaying lxml version numbers """
+
+        return ".".join(map(str, version))
+
+    def reset (self):
+    
+        """ Reset the mutator """
+
+        self.tree = deepcopy(self.input_tree)
+
+    def init_from_string (self, input_string):
+    
+        """ Initialize the mutator from a XML string """
+
+        # Get a pointer to the top-element
+        self.input_tree = self.__parse_xml(input_string)
+
+        # Get a working copy
+        self.tree = deepcopy(self.input_tree)
+
+    def save_to_string (self):
+    
+        """ Return the current XML document as UTF-8 string """
+
+        # Return a text version of the tree
+        return self.__serialize_xml(self.tree)
+
+    def __pick_element (self, exclude_root_node = False):
+    
+        """ Pick a random element from the current document """
+
+        # Get a list of all elements, but nodes like PI and comments
+        elems = list(self.tree.getroot().iter(tag=ET.Element))
+
+        # Is the root node excluded?
+        if exclude_root_node:
+            start = 1
+        else:
+            start = 0
+
+        # Pick a random element
+        try:
+            elem_id = random.randint (start, len(elems) - 1)
+            elem = elems[elem_id]
+        except ValueError:
+            # Should only occurs if "exclude_root_node = True"
+            return (None, None)
+
+        return (elem_id, elem)
+
+    def __fuzz_attribute (self):
+    
+        """ Fuzz (part of) an attribute value """
+
+        # Select a node to modify
+        (rand_elem_id, rand_elem) = self.__pick_element()
+
+        # Get all the attributes
+        attribs = rand_elem.keys()
+
+        # Is there attributes?
+        if len(attribs) < 1:
+            if self.verbose:
+                print("No attribute: can't replace!")
+            return
+
+        # Pick a random attribute
+        rand_attrib_id = random.randint (0, len(attribs) - 1)
+        rand_attrib = attribs[rand_attrib_id]
+
+        # We have the attribute to modify
+        # Get its value
+        attrib_value = rand_elem.get(rand_attrib);
+        # print("- Value: " + attrib_value)
+
+        # Should we work on the whole value?
+        func_call = "(?P<func>[a-zA-Z:\-]+)\((?P<args>.*?)\)"
+        p = re.compile(func_call)
+        l = p.findall(attrib_value)
+        if random.choice((True,False)) and l:
+            # Randomly pick one the function calls
+            (func, args) = random.choice(l)
+            # Split by "," and randomly pick one of the arguments
+            value = random.choice(args.split(','))
+            # Remove superfluous characters
+            unclean_value = value
+            value = value.strip(" ").strip("'")
+            # print("Selected argument: [%s]" % value)
+        else:
+            value = attrib_value
+
+        # For each type, define some possible replacement values
+        choices_number =    ( \
+                                "0", \
+                                "11111", \
+                                "-128", \
+                                "2", \
+                                "-1", \
+                                "1/3", \
+                                "42/0", \
+                                "1094861636 idiv 1.0", \
+                                "-1123329771506872 idiv 3.8", \
+                                "17=$numericRTF", \
+                                str(3 + random.randrange(0, 100)), \
+                            )
+
+        choices_letter =    ( \
+                                "P" * (25 * random.randrange(1, 100)), \
+                                "%s%s%s%s%s%s", \
+                                "foobar", \
+                            )
+
+        choices_alnum =     ( \
+                                "Abc123", \
+                                "020F0302020204030204", \
+                                "020F0302020204030204" * (random.randrange(5, 20)), \
+                            )
+
+        # Fuzz the value
+        if random.choice((True,False)) and value == "":
+
+            # Empty
+            new_value = value
+
+        elif random.choice((True,False)) and value.isdigit():
+
+            # Numbers
+            new_value = random.choice(choices_number)
+
+        elif random.choice((True,False)) and value.isalpha():
+
+            # Letters
+            new_value = random.choice(choices_letter)
+
+        elif random.choice((True,False)) and value.isalnum():
+
+            # Alphanumeric
+            new_value = random.choice(choices_alnum)
+
+        else:
+
+            # Default type
+            new_value = random.choice(choices_alnum + choices_letter + choices_number)
+
+        # If we worked on a substring, apply changes to the whole string
+        if value != attrib_value:
+            # No ' around empty values
+            if new_value != "" and value != "":
+                new_value = "'" + new_value + "'"
+            # Apply changes
+            new_value = attrib_value.replace(unclean_value, new_value)
+
+        # Log something
+        if self.verbose:
+            print("Fuzzing attribute #%i '%s' of tag #%i '%s'" % (rand_attrib_id, rand_attrib, rand_elem_id, rand_elem.tag))
+
+        # Modify the attribute
+        rand_elem.set(rand_attrib, new_value.decode("utf-8"))
+
+    def __del_node_and_children (self):
+
+        """ High-level minimizing mutator
+            Delete a random node and its children (i.e. delete a random tree) """
+
+        self.__del_node(True)
+
+    def __del_node_but_children (self):
+
+        """ High-level minimizing mutator
+            Delete a random node but its children (i.e. link them to the parent of the deleted node) """
+
+        self.__del_node(False)
+
+    def __del_node (self, delete_children):
+    
+        """ Called by the __del_node_* mutators """
+
+        # Select a node to modify (but the root one)
+        (rand_elem_id, rand_elem) = self.__pick_element (exclude_root_node = True)
+
+        # If the document includes only a top-level element
+        # Then we can't pick a element (given that "exclude_root_node = True") 
+
+        # Is the document deep enough?
+        if rand_elem is None:
+            if self.verbose:
+                print("Can't delete a node: document not deep enough!")
+            return
+
+        # Log something
+        if self.verbose:
+            but_or_and = "and" if delete_children else "but"
+            print("Deleting tag #%i '%s' %s its children" % (rand_elem_id, rand_elem.tag, but_or_and))
+
+        if delete_children is False:
+            # Link children of the random (soon to be deleted) node to its parent
+            for child in rand_elem:
+                rand_elem.getparent().append(child)
+            
+        # Remove the node
+        rand_elem.getparent().remove(rand_elem)
+
+    def __del_content (self):
+    
+        """ High-level minimizing mutator
+            Delete the attributes and children of a random node """
+
+        # Select a node to modify
+        (rand_elem_id, rand_elem) = self.__pick_element()
+
+        # Log something
+        if self.verbose:
+            print("Reseting tag #%i '%s'" % (rand_elem_id, rand_elem.tag))
+
+        # Reset the node
+        rand_elem.clear()
+
+    def __del_attribute (self):
+     
+        """ High-level minimizing mutator
+            Delete a random attribute from a random node """
+
+        # Select a node to modify
+        (rand_elem_id, rand_elem) = self.__pick_element()
+
+        # Get all the attributes
+        attribs = rand_elem.keys()
+
+        # Is there attributes?
+        if len(attribs) < 1:
+            if self.verbose:
+                print("No attribute: can't delete!")
+            return
+
+        # Pick a random attribute
+        rand_attrib_id = random.randint (0, len(attribs) - 1)
+        rand_attrib = attribs[rand_attrib_id]
+
+        # Log something
+        if self.verbose:
+            print("Deleting attribute #%i '%s' of tag #%i '%s'" % (rand_attrib_id, rand_attrib, rand_elem_id, rand_elem.tag))
+
+        # Delete the attribute
+        rand_elem.attrib.pop(rand_attrib)
+
+    def mutate (self, min=1, max=5):
+    
+        """ Execute some high-level mutators between $min and $max times, then some medium-level ones """
+
+        # High-level mutation
+        self.__exec_among(self, self.hl_mutators_all, min, max)
+
--- a/python_mutators/wrapper_afl_min.py
+++ b/python_mutators/wrapper_afl_min.py
@ -0,0 +1,117 @@
+#!/usr/bin/env python
+
+from XmlMutatorMin import XmlMutatorMin
+
+# Default settings (production mode)
+
+__mutator__ = None
+__seed__ = "RANDOM"
+__log__ = False
+__log_file__ = "wrapper.log"
+
+# AFL functions
+
+def log(text):
+    """
+          Logger
+    """
+
+    global __seed__
+    global __log__
+    global __log_file__
+
+    if __log__:
+        with open(__log_file__, "a") as logf:
+            logf.write("[%s] %s\n" % (__seed__, text))
+
+def init(seed):
+    """
+          Called once when AFL starts up. Seed is used to identify the AFL instance in log files
+    """
+
+    global __mutator__
+    global __seed__
+
+    # Get the seed
+    __seed__ = seed
+
+    # Create a global mutation class
+    try:
+	__mutator__ = XmlMutatorMin(__seed__, verbose=__log__)
+        log("init(): Mutator created")
+    except RuntimeError as e:
+        log("init(): Can't create mutator: %s" % e.message)
+
+def fuzz(buf, add_buf):
+    """
+          Called for each fuzzing iteration.
+    """
+
+    global __mutator__ 
+
+    # Do we have a working mutator object?
+    if __mutator__ is None:
+        log("fuzz(): Can't fuzz, no mutator available")
+        return buf
+
+    # Try to use the AFL buffer
+    via_buffer = True
+
+    # Interpret the AFL buffer (an array of bytes) as a string
+    if via_buffer:
+        try:
+            buf_str = str(buf)
+            log("fuzz(): AFL buffer converted to a string")
+        except:
+            via_buffer = False
+            log("fuzz(): Can't convert AFL buffer to a string")
+
+    # Load XML from the AFL string
+    if via_buffer:
+        try:
+            __mutator__.init_from_string(buf_str)
+            log("fuzz(): Mutator successfully initialized with AFL buffer (%d bytes)" % len(buf_str))
+        except:
+            via_buffer = False
+            log("fuzz(): Can't initialize mutator with AFL buffer")
+
+    # If init from AFL buffer wasn't succesful
+    if not via_buffer:
+         log("fuzz(): Returning unmodified AFL buffer")
+         return buf
+
+    # Sucessful initialization -> mutate
+    try:
+        __mutator__.mutate(max=5)
+        log("fuzz(): Input mutated")
+    except:
+        log("fuzz(): Can't mutate input => returning buf")
+        return buf
+            
+    # Convert mutated data to a array of bytes
+    try:
+        data = bytearray(__mutator__.save_to_string())
+        log("fuzz(): Mutated data converted as bytes")
+    except:
+        log("fuzz(): Can't convert mutated data to bytes => returning buf")
+        return buf
+
+    # Everything went fine, returning mutated content
+    log("fuzz(): Returning %d bytes" % len(data))
+    return data
+
+# Main (for debug)
+
+if __name__ == '__main__':
+
+    __log__ = True
+    __log_file__ = "/dev/stdout"
+    __seed__ = "RANDOM"
+
+    init(__seed__)
+
+    in_1 = bytearray("<foo ddd='eeee'>ffff<a b='c' d='456' eee='ffffff'>zzzzzzzzzzzz</a><b yyy='YYY' zzz='ZZZ'></b></foo>")
+    in_2 = bytearray("<abc abc123='456' abcCBA='ppppppppppppppppppppppppppppp'/>")
+    out = fuzz(in_1, in_2)
+    print(out)
+