The original `ExecuteCommand()` called `system()` from the C library.
The C library implementation of this on macOS contains a mutex which
serializes calls to `system()`. This prevented the `-jobs=` flag
from running copies of the fuzzing binary in parallel which is
the opposite of what is intended.
To fix this on macOS an alternative implementation of `ExecuteCommand()`
is provided that can be used concurrently. This is provided in
`FuzzerUtilDarwin.cpp` which is guarded to only compile code on Apple
platforms. The existing implementation has been moved to a new file
`FuzzerUtilLinux.cpp` which is guarded to only compile code on Linux.
This commit includes a simple test to check that LibFuzzer is being
executed in parallel when requested.
Differential Revision: https://reviews.llvm.org/D22742
llvm-svn: 278544
The motivation for this change is to fix linking issues on OSX.
However this only partially fixes linking issues (the uninstrumented
tests and a few others won't succesfully link yet).
This change introduces a struct of function pointers
(``fuzzer::ExternalFuntions``) which when initialised will point to the
optional functions if they are available. Currently these
``LLVMFuzzerInitialize`` and ``LLVMFuzzerCustomMutator`` functions.
Two implementations of ``fuzzer::ExternalFunctions`` constructor are
provided one for Linux and one for OSX.
The OSX implementation uses ``dlsym()`` because the prior implementation
using weak symbols does not work unless the additional flags are passed
to the linker.
The Linux implementation continues to use weak symbols because the
``dlsym()`` approach does not work unless additional flags are passed
to the linker.
Differential Revision: http://reviews.llvm.org/D20741
llvm-svn: 271491
Previously CMake would successfully configure and compile (with warnings
about ``-fsanitize-coverage=...`` being unused) but the tests LibFuzzer
tests would fail.
Differential Revision: http://reviews.llvm.org/D20662
llvm-svn: 270913
Previously the flags were only being set correctly when the
build type was "Release". Now the build should work properly
for all the supported build types. When building libFuzzer
the optimization level respects whatever is used for the
rest of LLVM but for the LibFuzzer tests we force -O0.
Differential Revision: http://reviews.llvm.org/D20558
llvm-svn: 270912
Newer versions of libstdc++ (4.9+), as well as libc++, depend directly on
libpthread from the standard library headers, so libfuzzer needs to declare
a standard library dependency.
llvm-svn: 255745
Summary:
This adds a SHA1 implementation taken from public domain code.
The change is trivial, but as it involves third-party code I'd like
a second pair of eyes before commit.
LibFuzzer can not use SHA1 from openssl because openssl may not be available
and because we may be fuzzing openssl itself.
Using sha1sum via a pipe is too slow.
Test Plan: n/a
Reviewers: chandlerc
Reviewed By: chandlerc
Subscribers: majnemer, llvm-commits
Differential Revision: http://reviews.llvm.org/D9733
llvm-svn: 237400
Summary:
This adds a simple DFSan-based (i.e. taint-guided) fuzzer mutator,
see the comments for details.
Test Plan: a test added
Reviewers: samsonov, pcc
Reviewed By: samsonov, pcc
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8669
llvm-svn: 233613
Summary: Add test targets and the lit-style runner.
Test Plan: Run the tests on bot.
Reviewers: samsonov
Reviewed By: samsonov
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7217
llvm-svn: 227389
Summary:
A simple genetic in-process coverage-guided fuzz testing library.
I've used this fuzzer to test clang-format
(it found 12+ bugs, thanks djasper@ for the fixes!)
and it may also help us test other parts of LLVM.
So why not keep it in the LLVM repository?
I plan to add the cmake build rules later (in a separate patch, if that's ok)
and also add a clang-format-fuzzer target.
See README.txt for details.
Test Plan: Tests will follow separately.
Reviewers: djasper, chandlerc, rnk
Reviewed By: rnk
Subscribers: majnemer, ygribov, dblaikie, llvm-commits
Differential Revision: http://reviews.llvm.org/D7184
llvm-svn: 227252
