When trying to debug some `compiler-rt` unittests, I initially had a hard
time because
- even in a `Debug` build one needs to set `COMPILER_RT_DEBUG` to get
debugging info for some of the code and
- even so the unittests used a hardcoded `-O2` which often makes debugging
impossible.
This patch addresses this by instead using `-O0` if `COMPILER_RT_DEBUG`.
Two tests in `sanitizer_type_traits_test.cpp` need to be disabled since
they have undefined references to `__sanitizer::integral_constant<bool,
true>::value`.
Tested on `sparcv9-sun-solaris2.11`, `amd64-pc-solaris2.11`, and
`x86_64-pc-linux-gnu`.
Differential Revision: https://reviews.llvm.org/D91620
We no longer support the use of LLVM_ENABLE_PROJECTS for libcxx and
libcxxabi. We don't use paths to libcxx and libcxxabi in compiler-rt.
Differential Revision: https://reviews.llvm.org/D126905
We no longer support the use of LLVM_ENABLE_PROJECTS for libcxx and
libcxxabi. We don't use paths to libcxx and libcxxabi in compiler-rt.
Differential Revision: https://reviews.llvm.org/D126905
The upstream project ships CMake rules for building vanilla gtest/gmock which conflict with the names chosen by LLVM. Since LLVM's build rules here are quite specific to LLVM, prefixing them to avoid collision is the right thing (i.e. there does not appear to be a path to letting someone *replace* LLVM's googletest with one they bring, so co-existence should be the goal).
This allows LLVM to be included with testing enabled within projects that themselves have a dependency on an official gtest release.
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D120789
Previously, when the fuzzing loop replaced an input in the corpus, it didn't update the execution time of the input. Therefore, some schedulers (e.g. Entropic) would adjust weights based on the incorrect execution time.
This patch updates the execution time of the input when replacing it.
Reviewed By: morehouse
Differential Revision: https://reviews.llvm.org/D111479
Previously, PrintASCII would print the string "\ta" as "\x09a". However,
in C/C++ those strings are not the same: the trailing 'a' is part of the
escape sequence, which means it's equivalent to "\x9a". This is an
annoying quirk of the standard. (See
https://eel.is/c++draft/lex.ccon#nt:hexadecimal-escape-sequence)
To fix this, output three-digit octal escape sequences instead. Since
octal escapes are limited to max three digits, this avoids the problem
of subsequent characters unintentionally becoming part of the escape
sequence.
Dictionary files still use the non-C-compatible hex escapes, but I
believe we can't change the format since it comes from AFL, and
libfuzzer never writes such files, it only has to read them, so they're
not affected by this change.
Differential revision: https://reviews.llvm.org/D110920
Extend the existing single-pass algorithm for `Merger::Merge` with an algorithm that gives better results. This new implementation can be used with a new **set_cover_merge=1** flag.
This greedy set cover implementation gives a substantially smaller final corpus (40%-80% less testcases) while preserving the same features/coverage. At the same time, the execution time penalty is not that significant (+50% for ~1M corpus files and far less for smaller corpora). These results were obtained by comparing several targets with varying size corpora.
Change `Merger::CrashResistantMergeInternalStep` to collect all features from each file and not just unique ones. This is needed for the set cover algorithm to work correctly. The implementation of the algorithm in `Merger::SetCoverMerge` uses a bitvector to store features that are covered by a file while performing the pass. Collisions while indexing the bitvector are ignored similarly to the fuzzer.
Reviewed By: morehouse
Differential Revision: https://reviews.llvm.org/D105284
This change introduces libMutagen/libclang_rt.mutagen.a as a subset of libFuzzer/libclang_rt.fuzzer.a. This library contains only the fuzzing strategies used by libFuzzer to produce new test inputs from provided inputs, dictionaries, and SanitizerCoverage feedback.
Most of this change is simply moving sections of code to one side or the other of the library boundary. The only meaningful new code is:
* The Mutagen.h interface and its implementation in Mutagen.cpp.
* The following methods in MutagenDispatcher.cpp:
* UseCmp
* UseMemmem
* SetCustomMutator
* SetCustomCrossOver
* LateInitialize (similar to the MutationDispatcher's original constructor)
* Mutate_AddWordFromTORC (uses callbacks instead of accessing TPC directly)
* StartMutationSequence
* MutationSequence
* DictionaryEntrySequence
* RecommendDictionary
* RecommendDictionaryEntry
* FuzzerMutate.cpp (which now justs sets callbacks and handles printing)
* MutagenUnittest.cpp (which adds tests of Mutagen.h)
A note on performance: This change was tested with a 100 passes of test/fuzzer/LargeTest.cpp with 1000 runs per pass, both with and without the change. The running time distribution was qualitatively similar both with and without the change, and the average difference was within 30 microseconds (2.240 ms/run vs 2.212 ms/run, respectively). Both times were much higher than observed with the fully optimized system clang (~0.38 ms/run), most likely due to the combination of CMake "dev mode" settings (e.g. CMAKE_BUILD_TYPE="Debug", LLVM_ENABLE_LTO=OFF, etc.). The difference between the two versions built similarly seems to be "in the noise" and suggests no meaningful performance degradation.
Reviewed By: morehouse
Differential Revision: https://reviews.llvm.org/D102447
This change introduces libMutagen/libclang_rt.mutagen.a as a subset of libFuzzer/libclang_rt.fuzzer.a. This library contains only the fuzzing strategies used by libFuzzer to produce new test inputs from provided inputs, dictionaries, and SanitizerCoverage feedback.
Most of this change is simply moving sections of code to one side or the other of the library boundary. The only meaningful new code is:
* The Mutagen.h interface and its implementation in Mutagen.cpp.
* The following methods in MutagenDispatcher.cpp:
* UseCmp
* UseMemmem
* SetCustomMutator
* SetCustomCrossOver
* LateInitialize (similar to the MutationDispatcher's original constructor)
* Mutate_AddWordFromTORC (uses callbacks instead of accessing TPC directly)
* StartMutationSequence
* MutationSequence
* DictionaryEntrySequence
* RecommendDictionary
* RecommendDictionaryEntry
* FuzzerMutate.cpp (which now justs sets callbacks and handles printing)
* MutagenUnittest.cpp (which adds tests of Mutagen.h)
A note on performance: This change was tested with a 100 passes of test/fuzzer/LargeTest.cpp with 1000 runs per pass, both with and without the change. The running time distribution was qualitatively similar both with and without the change, and the average difference was within 30 microseconds (2.240 ms/run vs 2.212 ms/run, respectively). Both times were much higher than observed with the fully optimized system clang (~0.38 ms/run), most likely due to the combination of CMake "dev mode" settings (e.g. CMAKE_BUILD_TYPE="Debug", LLVM_ENABLE_LTO=OFF, etc.). The difference between the two versions built similarly seems to be "in the noise" and suggests no meaningful performance degradation.
Reviewed By: morehouse
Differential Revision: https://reviews.llvm.org/D102447
This change adds additional unit tests for fuzzer::Merger::Parse and fuzzer::Merger::Merge in anticipation of additional changes to the merge control file format to support cross-process fuzzing.
It modifies the parameter handling of Merge slightly in order to make NewFeatures and NewCov consistent with NewFiles; namely, Merge *replaces* the contents of these output parameters rather than accumulating them (thereby fixing a buggy return value).
This is change 1 of (at least) 18 for cross-process fuzzing support.
Reviewed By: morehouse
Differential Revision: https://reviews.llvm.org/D94506
This makes `PickValueInArray` work for `std::array<T, s>` (C++11). I've also tested the C++17 `std::array` (with compiler-deduced template parameters)
```
Author:
MarcoFalke <falke.marco@gmail.com>
```
Reviewed By: Dor1s
Differential Revision: https://reviews.llvm.org/D93412
This patch scales the energy computed by the Entropic schedule based on the
execution time of each input. The input execution time is compared with the
average execution time of inputs in the corpus, and, based on the amount by
which they differ, the energy is scaled from 0.1x (for inputs executing slow) to
3x (for inputs executing fast). Note that the exact scaling criteria and formula
is borrowed from AFL.
On FuzzBench, this gives a sizeable throughput increase, which in turn leads to
more coverage on several benchmarks. For details, see the following report.
https://storage.googleapis.com/fuzzer-test-suite-public/exectime-report/index.html
Differential Revision: https://reviews.llvm.org/D86092
This patch adds an option "keep_seed" to keep all initial seed inputs in the
corpus. Previously, only the initial seed inputs that find new coverage were
added to the corpus, and all the other initial inputs were discarded. We
observed in some circumstances that useful initial seed inputs are discarded as
they find no new coverage, even though they contain useful fragments in them
(e.g., SQLITE3 FuzzBench benchmark). This newly added option provides a way to
keeping seed inputs in the corpus for those circumstances. With this patch, and
with -keep_seed=1, all initial seed inputs are kept in the corpus regardless of
whether they find new coverage or not. Further, these seed inputs are not
replaced with smaller inputs even if -reduce_inputs=1.
Differential Revision: https://reviews.llvm.org/D86577
Summary:
This is collaboration between Marcel Boehme @ Monash, Australia and Valentin Manès plus Sang Kil Cha @ KAIST, South Korea.
We have made a few modifications to boost LibFuzzer performance by changing how weights are assigned to the seeds in the corpus. Essentially, seeds that reveal more "information" about globally rare features are assigned a higher weight. Our results on the Fuzzer Test Suite seem quite promising. In terms of bug finding, our Entropic patch usually finds the same errors much faster and in more runs. In terms of coverage, our version Entropic achieves the same coverage in less than half the time for the majority of subjects. For the lack of space, we shared more detailed performance results directly with @kcc. We'll publish the preprint with all the technical details as soon as it is accepted. Happy to share if you drop us an email.
There should be plenty of opportunities to optimise further. For instance, while Entropic achieves the same coverage in less than half the time, Entropic has a much lower #execs per second. We ran the perf-tool and found a few performance bottlenecks.
Thanks for open-sourcing LibFuzzer (and the entire LLVM Compiler Infrastructure)! This has been such a tremendous help to my research.
Patch By: Marcel Boehme
Reviewers: kcc, metzman, morehouse, Dor1s, vitalybuka
Reviewed By: kcc
Subscribers: dgg5503, Valentin, llvm-commits, kcc
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73776
Renames GTEST_NO_LLVM_RAW_OSTREAM -> GTEST_NO_LLVM_SUPPORT and guards
the new features behind it.
This reverts commit a063bcf3ef5a879adbe9639a3c187d876eee0e66.
llvm-svn: 369527
Summary:
Also slightly cleaned up the comments and changed the header's extension
back to `.h` as per comments on https://reviews.llvm.org/D65812.
New methods added:
* `ConsumeProbability` returns [0.0, 1.0] by consuming an unsigned integer value
from the input data and dividing that value by the integer's max value.
* `ConsumeFloatingPointInRange` returns a floating point value in the given
range. Relies on `ConsumeProbability` method. This method does not have the
limitation of `std::uniform_real_distribution` that requires the given range
to be <= the floating point type's max. If the range is too large, this
implementation will additionally call `ConsumeBool` to decide whether the
result will be in the first or the second half of the range.
* `ConsumeFloatingPoint` returns a floating point value in the range
`[std::numeric_limits<T>::lowest(), std::numeric_limits<T>::min()]`.
Tested on Linux, Mac, Windows.
Reviewers: morehouse
Reviewed By: morehouse
Subscribers: kubamracek, mgorny, dberris, delcypher, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D65905
llvm-svn: 368331
Summary:
.hpp makes more sense for this header as it's C++ only, plus it
contains the actual implementation.
Reviewers: Dor1s
Reviewed By: Dor1s
Subscribers: kubamracek, dberris, mgorny, delcypher, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D65812
llvm-svn: 368054
Summary:
FuzzedDataProvider is a helper class for writing fuzz targets that fuzz
multple inputs simultaneously. The header is supposed to be used for fuzzing
engine agnostic fuzz targets (i.e. the same target can be used with libFuzzer,
AFL, honggfuzz, and other engines). The common thing though is that fuzz targets
are typically compiled with clang, as it provides all sanitizers as well as
different coverage instrumentation modes. Therefore, making this FDP class a
part of the compiler-rt installation package would make it easier to develop
and distribute fuzz targets across different projects, build systems, etc.
Some context also available in https://github.com/google/oss-fuzz/pull/2547.
This CL does not delete the header from `lib/fuzzer/utils` directory in order to
provide the downstream users some time for a smooth migration to the new
header location.
Reviewers: kcc, morehouse
Reviewed By: morehouse
Subscribers: lebedev.ri, kubamracek, dberris, mgorny, delcypher, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D65661
llvm-svn: 367917
Summary:
This way the test would better match the intended usage of the header,
plus it makes some additional testing (e.g. in CI) a bit easier to set up.
Reviewers: morehouse
Reviewed By: morehouse
Subscribers: mgorny, delcypher, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D64440
llvm-svn: 365544
Summary:
The following changes are made based on the feedback from Tim King:
- Removed default template parameters, to have less assumptions.
- Implemented `ConsumeBytesWithTerminator` method.
- Made `PickValueInArray` method work with `initializer_list` argument.
- Got rid of `data_type` type alias, that was redundant.
- Refactored `ConsumeBytes` logic into a private method for better code reuse.
- Replaced implementation defined unsigned to signed conversion.
- Fixed `ConsumeRandomLengthString` to always call `shrink_to_fit`.
- Clarified and fixed some commments.
- Applied clang-format to both the library and the unittest source.
Tested on Linux, Mac, Windows.
Reviewers: morehouse, metzman
Reviewed By: morehouse
Subscribers: delcypher, #sanitizers, llvm-commits, kcc
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D63348
llvm-svn: 363735
Summary:
This class is useful for writing fuzz target that have multiple inputs.
Current CL imports the existing `FuzzedDataProvider` from Chromium
without any modifications. Feel free to review it thoroughly, if you're
interested, but I'd prefer changing the class in a follow up CL.
The CL also introduces an exhaustive test for the library, as the behavior
of `FuzzedDataProvider` must not change over time.
In follow up CLs I'm planning on changing some implementation details
(I can share a doc with some comments to be addressed). After that, we
will document how `FuzzedDataProvider` should be used.
I have tested this on Linux, Windows and Mac platforms.
Reviewers: morehouse, metzman, kcc
Reviewed By: morehouse
Subscribers: metzman, thakis, rnk, mgorny, ormris, delcypher, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D62733
llvm-svn: 363071
Summary:
This fixes inconsistent symbol visibility. This shows up as a linker
warning if r336238 (43f633564e338a6dde83d49a48e5bfcbfdce292c) is
reverted.
```
ld: warning: direct access in function 'fuzzer::CleanseCrashInput(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, fuzzer::fuzzer_allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&, fuzzer::FuzzingOptions const&)' from file '/Volumes/data/dev/llvm/upstream/master/builds/projects/compiler-rt/lib/fuzzer/tests/libRTFuzzerTest.x86_64.a(FuzzerDriver.cpp.o)' to global weak symbol 'fuzzer::Command::ignoreRemainingArgs()::kIgnoreRemaining' from file 'FuzzerTestObjects.FuzzerUnittest.cpp.x86_64.o' means the weak symbol cannot be overridden
at runtime. This was likely caused by different translation units being compiled with different visibility settings.
```
r336238 just hid the issue rather than fixing the real issue. On macOS
and other platforms we usually compile with `-fvisibility=hidden` but
the unit tests were compiled without this flag.
Reviewers: george.karpenkov, kubamracek, kcc, yln
Subscribers: mgorny, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D58055
llvm-svn: 355143
According to the logs and local debugging there were two issues:
1) tsan tests listed libc++.a before the source file. That's usually
ok for shared libraries, but the linker will not add symbols from
a static library unless needed at that time. As a result the tests
that rely upon symbols from the library (and not only include the
headers) had undefined references.
To solve this I'm adding a new substitution %link_libcxx_tsan which
expands to libc++.a if available.
2) The target Fuzzer-x86_64-Test linked in SANITIZER_TEST_CXX_LIBRARIES
which defaults to -lstdc++. This resulted in error messages like
hidden symbol '_ZdlPv' is not defined locally
hidden symbol '_Znwm' is not defined locally
when using GNU gold (ld.bfd and lld are fine). Removing the linkage
is fine because we build a custom libc++ for that purpose.
llvm-svn: 354231
This changes add_custom_libcxx to also build libcxxabi and merges
the two into a static and hermetic library.
There are multiple advantages:
1) The resulting libFuzzer doesn't expose C++ internals and looks
like a plain C library.
2) We don't have to manually link in libstdc++ to provide cxxabi.
3) The sanitizer tests cannot interfere with an installed version
of libc++.so in LD_LIBRARY_PATH.
Differential Revision: https://reviews.llvm.org/D58013
llvm-svn: 354212
Add missed value "libcxxabi" and introduce SANITIZER_TEST_CXX for linking
unit tests. This needs to be a full C++ library and cannot be libcxxabi.
Recommit r354132 which I reverted in r354153 because it broke a sanitizer
bot. This was because of the "fixes" for pthread linking, so I've removed
these changes.
Differential Revision: https://reviews.llvm.org/D58012
llvm-svn: 354198
Add missed value "libcxxabi" and introduce SANITIZER_TEST_CXX for linking
unit tests. This needs to be a full C++ library and cannot be libcxxabi.
Differential Revision: https://reviews.llvm.org/D58012
llvm-svn: 354132
Vitaly Buka