Summary:
Namely, set the abort message, and allow to write the message to syslog if the
option is enabled.
Reviewers: alekseyshl
Reviewed By: alekseyshl
Subscribers: delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48902
llvm-svn: 336445
Summary:
This will make the behavior of __gcov_flush match the GCC behavior.
I would like to rename __gcov_flush to __llvm_gcov_flush (in case of programs linking to libraries built with different compilers), but I guess we can't for compatibility reasons.
Reviewers: davidxl
Reviewed By: davidxl
Subscribers: samsonov, vitalybuka, pcc, kcc, junbuml, glider, fhahn, eugenis, dvyukov, davidxl, srhines, chh, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D48538
llvm-svn: 336365
Summary:
The C interceptors were using `SIZE_T` defined in the interception library as
a `__sanitizer::uptr`. On some 32-bit platforms, this lead to the following
warning:
```
warning: declaration of ‘void* malloc(SIZE_T)’ conflicts with built-in declaration ‘void* malloc(unsigned int)’ [-Wbuiltin-declaration-mismatch]
INTERCEPTOR_ATTRIBUTE void *malloc(SIZE_T size) {
```
`__sanitizer::uptr` is indeed defined as an `unsigned long` on those.
So just include `stddef.h` and use `size_t` instead.
Reviewers: alekseyshl
Reviewed By: alekseyshl
Subscribers: delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D48885
llvm-svn: 336221
Summary:
In conjunction with the clang side change D48833, this will enable Scudo on
PPC64. I tested `check-scudo` on a powerpc64le box and everything passes.
Reviewers: eugenis, alekseyshl
Reviewed By: alekseyshl
Subscribers: mgorny, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48834
llvm-svn: 336213
Summary:
It would be useful for Flutter apps, especially, to be able to use
malloc hooks to debug memory leaks on Fuchsia. They're not able to do
this right now, so it'd be a nice bonus to throw in with the Scudo
switchover.
Reviewers: cryptoad, alekseyshl
Reviewed By: cryptoad
Differential Revision: https://reviews.llvm.org/D48618
llvm-svn: 336139
Summary:
Without this patch,
clang -fsanitize=address -xc =(printf 'int main(){}') -o a; ./a => deadlock in __asan_init>AsanInitInternal>AsanTSDInit>...>__getcontextx_size>_rtld_bind>rlock_acquire(rtld_bind_lock, &lockstate)
libexec/rtld-elf/rtld.c
wlock_acquire(rtld_bind_lock, &lockstate);
if (obj_main->crt_no_init)
preinit_main(); // unresolved PLT functions cannot be called here
lib/libthr/thread/thr_rtld.c
uc_len = __getcontextx_size(); // unresolved PLT function in libthr.so.3
check-xray tests currently rely on .preinit_array so we special case in
xray_init.cc
Subscribers: srhines, kubamracek, krytarowski, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D48806
llvm-svn: 336067
Currently in FreeBSD 12.0-CURRENT with trunk clang+compiler-rt, faulty -fsanitize=address executable hangs at 'urdlck' state.
Ka Ho Ng has verified that by backporting this to llvm 6.0.1, with use_madv_dontdump=1, shadow memory is not dumped.
ASAN_OPTIONS=abort_on_error=1:disable_coredump=0:use_madv_dontdump=1 ./a
Reviewers: dimitry, kcc, dvyukov, emaste, khng300
Subscribers: kubamracek, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D48257
llvm-svn: 336046
__gcov_flush is hidden.
For applications to dump profiling data of selected .so files,
they can use dlsym to find and call llvm_gcov_flush in each .so file.
Differential Revision: https://reviews.llvm.org/D45454
llvm-svn: 336019
The test checks that scs does NOT work correctly w/o runtime support.
That's a strange thing to test, and it is also flaky, because things
may just work if x18 happens to point to a writable page.
llvm-svn: 335982
Summary:
As well as some tests to ensure that various combinations of the clang command
line flags work (shared/static/minimal).
Reviewers: eugenis, alekseyshl, vitalybuka
Reviewed By: vitalybuka
Subscribers: srhines, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48553
llvm-svn: 335981
This change makes it pass both on libstdc++ and libc++-based toolchains.
The error was:
error: function-like macro '__GLIBC_PREREQ' is not defined
^
llvm-svn: 335936
NDK r16 provides glob.h, which makes this test pass.
Supporting different test outcomes depending on the version of NDK
add unnecessary complexity to the test harness. IMHO, it's OK to require
the latest stable release.
llvm-svn: 335935
Summary:
Report errno value on failed shadow memory madvise attempt and add a
hint message with the possible workaround.
Reviewers: eugenis
Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48668
llvm-svn: 335928
This change adds a support for multiarch style runtimes layout, so in
addition to the existing layout where runtimes get installed to:
lib/clang/$version/lib/$os
Clang now allows runtimes to be installed to:
lib/clang/$version/$target/lib
This also includes libc++, libc++abi and libunwind; today those are
assumed to be in Clang library directory built for host, with the
new layout it is possible to install libc++, libc++abi and libunwind
into the runtime directory built for different targets.
The use of new layout is enabled by setting the
LLVM_ENABLE_RUNTIME_TARGET_DIR CMake variable and is supported by both
projects and runtimes layouts. The runtimes CMake build has been further
modified to use the new layout when building runtimes for multiple
targets.
Differential Revision: https://reviews.llvm.org/D45604
llvm-svn: 335809
Under load, these tests tend to fail sporadically on our bots.
In my understanding, the signal handling is not guaranteed to happen
within 2 seconds, and the test is inherently flaky.
llvm-svn: 335792
The android buildbot moves the build outputs to a different directory
and rewrites the executable path, the DSO passed as an argument does not
get re-written. Use rpaths to load the DSO the same way the
test/cfi/cross-dso/ tests do and test the DSO name differently.
llvm-svn: 335777
Summary:
Setting UBSAN_OPTIONS=silence_unsigned_overflow=1 will silence all UIO
reports. This feature, combined with
-fsanitize-recover=unsigned-integer-overflow, is useful for providing
fuzzing signal without the excessive log output.
Helps with https://github.com/google/oss-fuzz/issues/910.
Reviewers: kcc, vsk
Reviewed By: vsk
Subscribers: vsk, kubamracek, Dor1s, llvm-commits
Differential Revision: https://reviews.llvm.org/D48660
llvm-svn: 335762
On Darwin/x86_64, asan may report the crashing line of NullDeref as line
19 (i.e the closing brace of the function), whereas on other targets we
see line 15 ("ptr[10]++").
The optimized debug info here isn't reliable enough to check.
rdar://problem/41526369
llvm-svn: 335747
On some ARM platforms this test depends on debug locations being
present on constant materialization code, which was eliminated in
r335497.
Relax the test to allow two outcomes: the backtrace either contains the
right line numbers, or no line numbers.
llvm-svn: 335741
build with an IDE (e.g. Xcode) as the generator.
Previously the global `USE_FOLDERS` property wasn't set in standalone
builds leading to existing settings of FOLDER not being respected.
In addition to this there were several targets that appeared at the top
level that were not interesting and clustered up the view. These have
been changed to be displayed in "Compiler-RT Misc".
Now when an Xcode project is generated from a standalone compiler-rt
build the project navigator is much less cluttered. The interesting
libraries should appear in "Compiler-RT Libraries" in the IDE.
Differential Revision: https://reviews.llvm.org/D48378
llvm-svn: 335728
Some warnings originating from googletest were causing bots to fail
while bulding unit tests. The sanitizers address this issue by not
using -Werror. We adopt this approach for libFuzzer.
llvm-svn: 335640
Similarly to CFI on virtual and indirect calls, this implementation
tries to use program type information to make the checks as precise
as possible. The basic way that it works is as follows, where `C`
is the name of the class being defined or the target of a call and
the function type is assumed to be `void()`.
For virtual calls:
- Attach type metadata to the addresses of function pointers in vtables
(not the functions themselves) of type `void (B::*)()` for each `B`
that is a recursive dynamic base class of `C`, including `C` itself.
This type metadata has an annotation that the type is for virtual
calls (to distinguish it from the non-virtual case).
- At the call site, check that the computed address of the function
pointer in the vtable has type `void (C::*)()`.
For non-virtual calls:
- Attach type metadata to each non-virtual member function whose address
can be taken with a member function pointer. The type of a function
in class `C` of type `void()` is each of the types `void (B::*)()`
where `B` is a most-base class of `C`. A most-base class of `C`
is defined as a recursive base class of `C`, including `C` itself,
that does not have any bases.
- At the call site, check that the function pointer has one of the types
`void (B::*)()` where `B` is a most-base class of `C`.
Differential Revision: https://reviews.llvm.org/D47567
llvm-svn: 335569
OpenBSD needs lld linker for sanitisers.
Disabling lint checking as some symbols cannot be defined and block the proper unit tests launch.
Reviewers: lebedev.ri, vitalybuka
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D48528
llvm-svn: 335524
__ubsan_on_report isn't defined as weak, and redefining it in a test is
not supported on Windows.
See the error message here: https://reviews.llvm.org/D48446
llvm-svn: 335523
Speculative fix for the interface definition of __ubsan_on_report for
the Windows bots:
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/30528
lib\ubsan\ubsan_interface.inc(55): error C2065: '__ubsan_on_report':
undeclared identifier
INTERCEPT_SANITIZER_WEAK_FUNCTION was the wrong macro to use to begin
with because __ubsan_on_report isn't weak. Reading through that macro,
it's still not clear to me why there is an undefined reference, though,
because it appears to define a dummy __ubsan_on_report shim.
llvm-svn: 335383
Add support to the ubsan runtime for reporting diagnostics to a monitor
process (e.g a debugger).
The Xcode IDE uses this by setting a breakpoint on __ubsan_on_report and
collecting diagnostic information via __ubsan_get_current_report_data,
which it then surfaces to users in the editor UI.
Testing for this functionality already exists in upstream lldb, here:
lldb/packages/Python/lldbsuite/test/functionalities/ubsan
Apart from that, this is `ninja check-{a,ub}san` clean.
Differential Revision: https://reviews.llvm.org/D48446
llvm-svn: 335371
MutexUnlock uses ReleaseStore on s->clock, which is the right thing to do.
However MutexReadOrWriteUnlock for writers uses Release on s->clock.
Make MutexReadOrWriteUnlock also use ReleaseStore for consistency and performance.
Unfortunately, I don't think any test can detect this as this only potentially
affects performance.
llvm-svn: 335322
Summary:
This patch follows D48373.
The point is to be able to use Scudo with `-fsanitize-minimal-runtime`. For that
we need a runtime that doesn't embed the UBSan one. This results in binaries
that can be compiled with `-fsanitize=scudo,integer -fsanitize-minimal-runtime`.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: mgorny, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D48377
llvm-svn: 335296
Similarly to Msan adding -pie provokes linkage issue, was spotted with pie_test.cc
Set to XFAIL for couple of unit tests.
Reviewers: vitalybuka, krytarowski, dim
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D48317
llvm-svn: 335166
Intercepts thr_exit call on FreeBSD.
Disable pthread key workflow.
The pthread key create approach does not function under FreeBSD as the libpthread is not initialised enough at this stage.
Reviewers: vitalybuka, krytarowski, dim
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D48268
llvm-svn: 335164
Summary:
Remove the generic error nadling policies and handle each allocator error
explicitly. Although more verbose, it allows for more comprehensive, precise
and actionable allocator related failure reports.
This finishes up the series of changes of the particular sanitizer
allocators, improves the internal allocator error reporting and removes
now unused policies.
Reviewers: vitalybuka, cryptoad
Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48328
llvm-svn: 335147
There's more platforms than just "ios" and "iossim" that we should support, and adding more lit config variables for each platform isn't great. Let's generalize and have a single value that determines what the platform under test is.
Differential Revision: https://reviews.llvm.org/D48309
llvm-svn: 335123
Summary:
Mark `isRssLimitExceeded` as `NOINLINE`, and move it's definition as well as
the one of `performSanityChecks` out of the class definition, as requested.
Reviewers: filcab, alekseyshl
Reviewed By: alekseyshl
Subscribers: delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48228
llvm-svn: 335054
Summary: `rm -f` does not write diagnostic message when there is no file argument.
Reviewers: dberris
Subscribers: delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D48311
llvm-svn: 335025
The initial implementaiton was using the C++ typeof keyword. This
causes the compiler to spew warnings unnecissarilly. This patch removes
the uses of typeof and replaces them with explicit typedefs of the
function types.
llvm-svn: 334981
Summary:
Following up on and complementing D44404 and other sanitizer allocators.
Currently many allocator specific errors (OOM, for example) are reported as
a text message and CHECK(0) termination, no stack, no details, not too
helpful nor informative. To improve the situation, detailed and structured
common errors were defined and reported under the appropriate conditions.
Common tests were generalized a bit to cover a slightly different TSan
stack reporting format, extended to verify errno value and returned
pointer value check is now explicit to facilitate debugging.
Reviewers: dvyukov
Subscribers: srhines, kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48087
llvm-svn: 334975
On targets that don't link internal libc++ (Fuchsia and Linux) but
use libc++ as their C++ library and libFuzzer is being built using
the just built compiler together with libc++ as part of runtimes, we
need an explicit dependency from libFuzzer object library to libc++ to
make sure the headers are available by the time we start building
libFuzzer.
Differential Revision: https://reviews.llvm.org/D48261
llvm-svn: 334928
This reverts commit r332924 and followup r332936 silencing a warning.
The change breaks the build on x86 if there is no 32-bit version of the
C++ libraries, see discussion in https://reviews.llvm.org/D47169.
llvm-svn: 334903
Summary: Otherwise if the file existed and was larger than the write size before the OpenFile call, the file will not be truncated and contain garbage in trailing bytes.
Reviewers: glider, kcc, vitalybuka
Subscribers: kubamracek, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D48250
llvm-svn: 334881
Summary:
Using associated metadata rather than llvm.used allows linkers to
perform dead stripping with -fsanitize-coverage=pc-table. Unfortunately
in my local tests, LLD was the only linker that made use of this metadata.
Partially addresses https://bugs.llvm.org/show_bug.cgi?id=34636 and fixes
https://github.com/google/sanitizers/issues/971.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: Dor1s, hiraditya, llvm-commits, kcc
Differential Revision: https://reviews.llvm.org/D48203
llvm-svn: 334858
Don't hardcode the architecture for Fuzzer tests which breaks when
compiler-rt is being compiled for architectures other than x86_64.
Differential Revision: https://reviews.llvm.org/D48207
llvm-svn: 334852
Summary:
The current `FailureHandler` mechanism was fairly opaque with regard to the
failure reason due to using `CHECK(0)`. Scudo is a bit different from the other
Sanitizers as it prefers to avoid spurious processing in its failure path. So
we just `dieWithMessage` using a somewhat explicit string.
Adapted the tests for the new strings.
While this takes care of the `OnBadRequest` & `OnOOM` failures, the next step
is probably to migrate the other Scudo failures in the same failes (header
corruption, invalid state and so on).
Reviewers: alekseyshl
Reviewed By: alekseyshl
Subscribers: filcab, mgorny, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48199
llvm-svn: 334843
The locks need to be implemented in a shared library to work correctly,
so they shouldn't be part of libclang_rt.builtins.a, except in
specialized scenarios where the user can prove it will only be linked
once.
Differential Revision: https://reviews.llvm.org/D47606
llvm-svn: 334779
Summary:
static fallback_mutex in msan_allocator.cc does not need the ctor
call and can be linker initialized.
Issue: https://github.com/google/sanitizers/issues/194
Reviewers: morehouse, eugenis
Subscribers: delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48145
llvm-svn: 334749
Summary:
Static ScopedInErrorReport::current_error_ can be linker initialized to
shave one global ctor call on application startup and be __asan_init-safe.
Global constructors in ASan runtime are bad because __asan_init runs
from preinit_array, before any such constructors.
Issue: https://github.com/google/sanitizers/issues/194
Reviewers: eugenis, morehouse
Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48141
llvm-svn: 334748
Glob patterns seem unsupported for commands executed by the emulated
shell (LIT_USE_INTERNAL_SHELL=1). Disable the test while that is being
addressed (a workaround such as "cd a-*" also does not work).
llvm-svn: 334719
Summary:
As a follow up to D48142 for Scudo, switch the `SpinMutex` to its static
counterpart, and ensure zero-initialization by memset'ing the whole class.
Reviewers: alekseyshl
Reviewed By: alekseyshl
Subscribers: delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48148
llvm-svn: 334716
Summary:
Error messages for dlsym used to be stored on the stack, but since
commit 2449ae7b ("ld.so: Introduce struct dl_exception") in glibc 2.27
these are now stored on the heap (and thus use the dlsym alloc pool).
Messages look like "undefined symbol: __isoc99_printf\0/path/to/a.out".
With many missing library functions and long object paths, the pool is
quickly exhausted. Implement a simple mechanism to return freed memory
to the pool (clear it in case it is used for calloc).
Fixes https://github.com/google/sanitizers/issues/957
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D47995
llvm-svn: 334703
In most of systems, this field is a signed type but in some it is an unsigned.
Reviewers: vitalybuka
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D48118
llvm-svn: 334686
On 32-bit macOS, "_fputs$UNIX2003" is called instead of "fputs" and the
"fgets_fputs" test fails. Apparently previous versions still passed the
test due to the internal implementation calling "strlen", but that does
not seem to be the case with macOS 10.13.3. Fixes r334450.
llvm-svn: 334670
Summary:
These four SpinMutex ctors was the only code executed in the ctor for
the static __asan::Allocator instance (same for the other sanitizers
allocators), which is supposed to be fully linker-initialized.
Also, when the global ctor for this allocator instance is executed,
this instance might already be initialized by __asan_init called from
.preinit_array.
Issue: https://github.com/google/sanitizers/issues/194
Reviewers: morehouse, eugenis, cryptoad
Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48142
llvm-svn: 334660
Respect a custom linker path provided by the user if one is present
(otherwise CMAKE_LINKER will have been set to the right value by CMake).
llvm-svn: 334654
Summary:
Move madvise(MADV_NOHUGEPAGE) for the meta shadow memory after the meta
shadow memory is mapped (currently it silently fails with ENOMEM).
Add a diagnostic message to detect similar problems in the future.
Reviewers: dvyukov
Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48097
llvm-svn: 334624
When XRay is being built as part of the just built compiler together
with libc++ as part of the runtimes build, we need an explicit
dependency from XRay to libc++ to make sure that the library is
available by the time we start building XRay.
Differential Revision: https://reviews.llvm.org/D48113
llvm-svn: 334575
aarch64/aosp_marlin-userdebug/OPR4.170623.016] builder unexpectedly
failed the fgets test (`assertion "fp" failed`). macOS unexpectedly
passes the fputs test without triggering ASAN.
llvm-svn: 334558
For paths without "%t" inside uniqueness is not guaranteed, and
potential collisions might be present.
Differential Revision: https://reviews.llvm.org/D47288
llvm-svn: 334546
Provide a buffer that the test harness can write into to provide
values for the environment variables. Format is a null-separated list
of VAR=value pairs; this is sufficent for our purpose.
Differential Revision: https://reviews.llvm.org/D47960
llvm-svn: 334522
Handling differently the iterations with the type limit and eventually an error message.
Reviewers: morehouse, kcc
Reviewed By: morehouse
Differential Revision: https://reviews.llvm.org/D47880
llvm-svn: 334510
Summary:
This CL adds support for aligned new/delete operators (C++17). Currently we
do not support alignment inconsistency detection on deallocation, as this
requires a header change, but the APIs are introduced and are functional.
Add a smoke test for the aligned version of the operators.
Reviewers: alekseyshl
Reviewed By: alekseyshl
Subscribers: delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D48031
llvm-svn: 334505
Summary:
This is part of the larger XRay Profiling Mode effort.
This patch implements the profile writing mechanism, to allow profiles
collected through the profiler mode to be persisted to files.
Follow-on patches would allow us to load these profiles and start
converting/analysing them through the `llvm-xray` tool.
Depends on D44620.
Reviewers: echristo, kpw, pelikan
Reviewed By: kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45998
llvm-svn: 334472
Summary:
This is part of the larger XRay Profiling Mode effort.
This patch implements the wiring required to enable us to actually
select the `xray-profiling` mode, and install the handlers to start
measuring the time and frequency of the function calls in call stacks.
The current way to get the profile information is by working with the
XRay API to `__xray_process_buffers(...)`.
In subsequent changes we'll implement profile saving to files, similar
to how the FDR and basic modes operate, as well as means for converting
this format into those that can be loaded/visualised as flame graphs. We
will also be extending the accounting tool in LLVM to support
stack-based function call accounting.
We also continue with the implementation to support building small
histograms of latencies for the `FunctionCallTrie::Node` type, to allow
us to actually approximate the distribution of latencies per function.
Depends on D45758 and D46998.
Reviewers: eizan, kpw, pelikan
Reviewed By: kpw
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D44620
llvm-svn: 334469
Summary:
With Android/Bionic, delay deallocation to round 2 of 4. It must run after
C++ thread_local destructors have been called, but before the final 2
rounds, because emutls calls free, and jemalloc then needs another 2
rounds to free its thread-specific data.
Fixes https://github.com/android-ndk/ndk/issues/687
Reviewers: cmtice, srhines, jyknight, chh, echristo
Reviewed By: srhines, chh, echristo
Subscribers: echristo, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D46978
llvm-svn: 334463
Summary:
Add fgets, fputs and puts to sanitizer_common. This adds ASAN coverage
for these functions, extends MSAN support from fgets to fputs/puts and
extends TSAN support from puts to fputs.
Fixes: https://github.com/google/sanitizers/issues/952
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D46545
llvm-svn: 334450
Summary:
Add allocator_returns_null.cc test to sanitizer_common and
remove all sanitizer-specific ones except:
- HWASan is not covered by sanitizer_common
- TSan allocator does not have comprehensive error reporting yet
Reviewers: vitalybuka
Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D47971
llvm-svn: 334433
Summary:
Now all sanitizers with improved allocator error reporting are covered
by these common tests.
Also, add pvalloc-specific checks to LSan.
HWASan is not covered by sanitizer_common, hence its own pvalloc
and other allocator tests.
Reviewers: vitalybuka
Subscribers: srhines, kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D47970
llvm-svn: 334424
Summary:
The shared TSD model in its current form doesn't scale. Here is an example of
rpc2-benchmark (with default parameters, which is threading heavy) on a 72-core
machines (defaulting to a `CompactSizeClassMap` and no Quarantine):
- with tcmalloc: 337K reqs/sec, peak RSS of 338MB;
- with scudo (exclusive): 321K reqs/sec, peak RSS of 637MB;
- with scudo (shared): 241K reqs/sec, peak RSS of 324MB.
This isn't great, since the exclusive model uses a lot of memory, while the
shared model doesn't even come close to be competitive.
This is mostly due to the fact that we are consistently scanning the TSD pool
starting at index 0 for an available TSD, which can result in a lot of failed
lock attempts, and touching some memory that needs not be touched.
This CL attempts to make things better in most situations:
- first, use a thread local variable on Linux (intead of pthread APIs) to store
the current TSD in the shared model;
- move the locking boolean out of the TSD: this allows the compiler to use a
register and potentially optimize out a branch instead of reading it from the
TSD everytime (we also save a tiny bit of memory per TSD);
- 64-bit atomic operations on 32-bit ARM platforms happen to be expensive: so
store the `Precedence` in a `uptr` instead of a `u64`. We lose some
nanoseconds of precision and we'll wrap around at some point, but the benefit
is worth it;
- change a `CHECK` to a `DCHECK`: this should never happen, but if something is
ever terribly wrong, we'll crash on a near null AV if the TSD happens to be
null;
- based on an idea by dvyukov@, we are implementing a bound random scan for
an available TSD. This requires computing the coprimes for the number of TSDs,
and attempting to lock up to 4 TSDs in an random order before falling back to
the current one. This is obviously slightly more expansive when we have just
2 TSDs (barely noticeable) but is otherwise beneficial. The `Precedence` still
basically corresponds to the moment of the first contention on a TSD. To seed
on random choice, we use the precedence of the current TSD since it is very
likely to be non-zero (since we are in the slow path after a failed `tryLock`)
With those modifications, the benchmark yields to:
- with scudo (shared): 330K reqs/sec, peak RSS of 327MB.
So the shared model for this specific situation not only becomes competitive but
outperforms the exclusive model. I experimented with some values greater than 4
for the number of TSDs to attempt to lock and it yielded a decrease in QPS. Just
sticking with the current TSD is also a tad slower. Numbers on platforms with
less cores (eg: Android) remain similar.
Reviewers: alekseyshl, dvyukov, javed.absar
Reviewed By: alekseyshl, dvyukov
Subscribers: srhines, kristof.beyls, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D47289
llvm-svn: 334410
Summary:
Running sanitized 32-bit x86 programs on glibc 2.27 crashes at startup, with:
ERROR: AddressSanitizer: SEGV on unknown address 0xf7a8a250 (pc 0xf7f807f4 bp 0xff969fc8 sp 0xff969f7c T16777215)
The signal is caused by a WRITE memory access.
#0 0xf7f807f3 in _dl_get_tls_static_info (/lib/ld-linux.so.2+0x127f3)
#1 0xf7a92599 (/lib/libasan.so.5+0x112599)
#2 0xf7a80737 (/lib/libasan.so.5+0x100737)
#3 0xf7f7e14f in _dl_init (/lib/ld-linux.so.2+0x1014f)
#4 0xf7f6eb49 (/lib/ld-linux.so.2+0xb49)
The problem is that glibc changed the calling convention for the GLIBC_PRIVATE
symbol that sanitizer uses (even when it should not, GLIBC_PRIVATE is exactly
for symbols that can change at any time, be removed etc.), see
https://sourceware.org/ml/libc-alpha/2017-08/msg00497.html
Fixes https://github.com/google/sanitizers/issues/954
Patch By: Jakub Jelinek
Reviewed By: vitalybuka, Lekensteyn
Differential Revison: https://reviews.llvm.org/D44623
llvm-svn: 334363
Summary:
Following up on and complementing D44404.
Currently many allocator specific errors (OOM, for example) are reported as
a text message and CHECK(0) termination, not stack, no details, not too
helpful nor informative. To improve the situation, detailed and
structured errors were defined and reported under the appropriate conditions.
Reviewers: eugenis
Subscribers: srhines, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D47793
llvm-svn: 334338
Summary:
Move the corresponding tests to the common folder (as all of the
sanitizer allocators will support this feature soon) and add the checks
specific to aligned_alloc to ASan and LSan allocators.
Reviewers: vitalybuka
Subscribers: srhines, kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D47924
llvm-svn: 334316
This change uses 'const' for the retryingWriteAll(...) API and removes
unnecessary 'static' local variables in getting the temporary filename.
llvm-svn: 334267
Summary:
This fixes http://llvm.org/PR32274.
This change adds a test to ensure that we're able to link XRay modes and
the runtime to binaries that don't need to depend on the C++ standard
library or a C++ ABI library. In particular, we ensure that this will work
with C programs compiled+linked with XRay.
To make the test pass, we need to change a few things in the XRay
runtime implementations to remove the reliance on C++ ABI features. In
particular, we change the thread-safe function-local-static
initialisation to use pthread_* instead of the C++ features that ensure
non-trivial thread-local/function-local-static initialisation.
Depends on D47696.
Reviewers: dblaikie, jfb, kpw, eizan
Reviewed By: kpw
Subscribers: echristo, eizan, kpw, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D46998
llvm-svn: 334262
Summary:
Currently many allocator specific errors (OOM, for example) are reported as
a text message and CHECK(0) termination, not stack, no details, not too
helpful nor informative. To improve the situation, detailed and
structured errors were defined and reported under the appropriate conditions.
Reviewers: eugenis
Subscribers: kubamracek, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D47798
llvm-svn: 334248
Summary: Otherwise we print things like [0/1] which is visually confusing.
Reviewers: kcc
Reviewed By: kcc
Subscribers: delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D47837
llvm-svn: 334234
When building the dylib, the C++ headers are fundamentally non-module.
They require special versions of the headers in order to provide C++03 and
legacy ABI definitions. This causes ODR issues when modules are enabled
during both the build and the usage of the libc++ headers.
This patch fixes the build error by disabling modules when building the
libc++ sources.
llvm-svn: 334220
-z,defs is incompatible with sanitizers so we need to filter it out
from the linker flags before passing them to the libc++ build.
Differential Revision: https://reviews.llvm.org/D47865
llvm-svn: 334212
Summary:
signal(3) on NetBSD calls internally sigaction(2).
Without disabling the recursive interceptor, there are
false positives about uninitialized memory reads inside libc.
This change fixes execution of such programs as sh(1) and
vmstat(1) in the NetBSD userland.
Sponsored by <The NetBSD Foundation>
Reviewers: eugenis, vitalybuka, joerg
Reviewed By: vitalybuka
Subscribers: llvm-commits, #sanitizers
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D47650
llvm-svn: 334168
On Fuchsia, we use libc++ compiled with ASan for our ASan built
executable which means we cannot use the same libc++ for libFuzzer when
building fuzz targets, instead we'll link a custom internal libc++ into
Fuchsia's build of libFuzzer like we already do on Linux.
Differential Revision: https://reviews.llvm.org/D47835
llvm-svn: 334144
Summary:
Added unit-test.
Fixed behavior of max_len argument.
Call read syscall with all available buffer, not just a page.
Reviewers: eugenis
Subscribers: kubamracek, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D46618
llvm-svn: 334130
By adding a ctor to create fuzzer_allocator<T> from fuzzer_allocator<U>.
This mimics construcotrs of std::allocator<T>.
Without the constructors, some versions of libstdc++ can't compile
`vector<bool, fuzzer_allocator<bool>>`.
llvm-svn: 334077
Summary:
This change extracts the recursion guard implementation from FDR Mode
and updates it to do the following:
- Do the atomic operation correctly to be signal-handler safe.
- Make it usable in both FDR and Basic Modes.
Before this change, the recursion guard relied on an unsynchronised read
and write on a volatile thread-local. A signal handler could then run in
between the read and the write, and then be able to run instrumented
code as part of the signal handling. Using an atomic exchange instead
fixes that by doing a proper mutual exclusion even in the presence of
signal handling.
Reviewers: kpw, eizan, jfb
Reviewed By: eizan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47696
llvm-svn: 334064
Summary:
Following up on and complementing D44404.
Currently many allocator specific errors (OOM, for example) are reported as
a text message and CHECK(0) termination, not stack, no details, not too
helpful nor informative. To improve the situation, detailed and
structured errors were defined and reported under the appropriate conditions.
Reviewers: eugenis
Subscribers: srhines, mgorny, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D47645
llvm-svn: 334034
We don't actually need to support multiple definitions of the functions
in FDR mode, but rather want to make sure that the implementation-detail
functions are marked as 'static' instead. This allows the inliner to do
its magic better for these functions too, since inline functions must
have a unique address across translation units.
llvm-svn: 334001
We planned to have FDR mode's internals unit-tested but it turns out
that we can just use end-to-end testing to verify the implementation.
We're going to move towards that approach more and more going forward,
so we're merging the implementation details of FDR mode into a single
.cc file.
We also avoid globbing in the XRay test helper macro, and instead list
down the files from the lib directory.
llvm-svn: 333986
Summary:
At least the ASan, MSan, TSan sanitizers require disabled ASLR on a NetBSD.
Introduce a generic CheckASLR() routine, that implements a check for the
current process. This flag depends on the global or per-process settings.
There is no simple way to disable ASLR in the build process from the
level of a sanitizer or during the runtime execution.
With ASLR enabled sanitizers that operate over the process virtual address
space can misbehave usually breaking with cryptic messages.
This check is dummy for !NetBSD.
Sponsored by <The NetBSD Foundation>
Reviewers: vitalybuka, joerg
Reviewed By: vitalybuka
Subscribers: cryptoad, kubamracek, llvm-commits, #sanitizers
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D47442
llvm-svn: 333985
Summary:
This is part of the work to address http://llvm.org/PR32274.
We remove the calls to array-placement-new and array-delete. This allows
us to rely on the internal memory management provided by
sanitizer_common/sanitizer_internal_allocator.h.
Reviewers: eizan, kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47695
llvm-svn: 333982
XRay doesn't use RTTI and doesn't need it. We disable it explicitly in
the CMake config, similar to how the other sanitizers already do it.
Part of the work to address http://llvm.org/PR32274.
llvm-svn: 333867
Summary:
This allows to build and link the code with e.g.
-fsanitize=dataflow -fsanitize-coverage=trace-pc-guard,pc-table,func,trace-cmp
w/o providing (all) the definitions of trace-cmp hooks.
This is similar to dummy hooks provided by asan/ubsan/msan for the same purpose,
except that some of the hooks need to have the __dfsw_ prefix
since we need dfsan to replace them.
Reviewers: pcc
Reviewed By: pcc
Subscribers: delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D47605
llvm-svn: 333796
Myriad only uses the platform interceptors for memory allocation
routines. Configure them properly.
Also add a missing guard around aligned alloc interceptor.
Differential Revision: https://reviews.llvm.org/D47641
llvm-svn: 333784
One test was marked as XFAIL for FreeBSD however still running when launching make check-xray
Reviewers: krytarowski, vitalybuka
Reviewed By: dberris
Differential Revision: https://reviews.llvm.org/D47622
llvm-svn: 333733
Address failures exhibited by ARMv8 bot in Thumb mode:
- Fix logic for fast unwinding support (i.e feature is not available for Thumb)
- Fix Unsupported and Requires rules to handle armv8 as well as soft and hard
float targets
- Un-xfail passing tests
Differential Revision: https://reviews.llvm.org/D47575
llvm-svn: 333729
Summary:
This is part of the larger XRay Profiling Mode effort.
This patch implements a centralised collector for `FunctionCallTrie`
instances, associated per thread. It maintains a global set of trie
instances which can be retrieved through the XRay API for processing
in-memory buffers (when registered). Future changes will include the
wiring to implement the actual profiling mode implementation.
This central service provides the following functionality:
* Posting a `FunctionCallTrie` associated with a thread, to the central
list of tries.
* Serializing all the posted `FunctionCallTrie` instances into
in-memory buffers.
* Resetting the global state of the serialized buffers and tries.
Depends on D45757.
Reviewers: echristo, pelikan, kpw
Reviewed By: kpw
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D45758
llvm-svn: 333624
We don't use the result of the query, and all tests pass if I remove it.
During startup, ASan spends a fair amount of time in this handler, and
the query is much more expensive than the call to commit the memory.
llvm-svn: 333595
On Myriad RTEMS, we don't need to treat the main thread differently.
The existing thread hooks will do the right thing, so get rid of all
the unneeded special logic.
Differential Revision: https://reviews.llvm.org/D47502
llvm-svn: 333504
Reset shadow memory during exit. Also update a cut-and-paste comment,
and do some minor refactoring of InitializeShadowMemory.
Differential Revision: https://reviews.llvm.org/D47501
llvm-svn: 333503
Fuchsia's _zx_port_wait no longer takes the count argument. This
change also updates all symbol uses to use the underscored versions.
Differential Revision: https://reviews.llvm.org/D47403
llvm-svn: 333328
The ordering of stderr/stdout writes might not be guaranteed,
and is irrelevant for this test.
Differential Revision: https://reviews.llvm.org/D47294
llvm-svn: 333245
With %run commands being present now, we want to make sure that they
stay present.
Differential Revision: https://reviews.llvm.org/D47293
llvm-svn: 333244
The bug was not previously exposed as only one architecture is currently
supported for libFuzzer.
Differential Revision: https://reviews.llvm.org/D47287
llvm-svn: 333242
LIT tests are used to test other cross-compiled architectures,
unit tests are only run on the host.
NFC now as currently only a single architecture is supported.
Differential Revision: https://reviews.llvm.org/D47286
llvm-svn: 333241
NFC now when libFuzzer supports only one architecture,
will stop being NFC after multiple architectures are supported.
Differential Revision: https://reviews.llvm.org/D47283
llvm-svn: 333239
Summary:
rL325492 disables FPU features when using soft floating point
(-mfloat-abi=soft), which is used internally when building for armv7. This
causes errors with builtins that utililize VFP instructions. With this change
we first check if VFP is enabled (by checking if the preprocessor macro
__VFP_FP__ is defined) before including such builtins.
Reviewers: rengolin, samsonov, compnerd, smeenai, javed.absar, peter.smith
Reviewed By: peter.smith
Subscribers: peter.smith, mgorny, kristof.beyls, chrib, llvm-commits
Differential Revision: https://reviews.llvm.org/D47217
llvm-svn: 333216
<sys/ustat.h> has been removed from glibc 2.28 by:
commit cf2478d53ad7071e84c724a986b56fe17f4f4ca7
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Sun Mar 18 11:28:59 2018 +0800
Deprecate ustat syscall interface
This patch uses pre-computed size of struct ustat for Linux to fix
https://bugs.llvm.org/show_bug.cgi?id=37418
Patch by H.J. Lu.
Differential Revision: https://reviews.llvm.org/D47281
llvm-svn: 333213
Summary:
The most common usecase for -runs=0 is for generating code coverage
over some corpus. Coverage reports based on sancov are about to be deprecated,
which means some external coverage solution will be used, e.g. Clang source
based code coverage, which does not use any sancov instrumentations and thus
libFuzzer would consider any input to be not interesting in that case.
Reviewers: kcc
Reviewed By: kcc
Subscribers: alex, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D47271
llvm-svn: 333116
Summary:
`sanitizer_internal_defs.h` didn't have this define, which will be useful in
an upcoming CL.
Reviewers: alekseyshl
Reviewed By: alekseyshl
Subscribers: kubamracek, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D47270
llvm-svn: 333109
Use compiler-rt builtins when selected as default Clang rtlib and avoid
explicitly passing -rtlib= flag to avoid the "argument unused during
compilation" warning.
This is a partial alternative to D47094 that does not rely on compiler
runtime checks.
Differential Revision: https://reviews.llvm.org/D47115
llvm-svn: 333037
Summary:
We need one library to support all of 39, 42 and 48 bit VMAs, and
there is no common address that works for all of them.
Reviewers: kcc, alekseyshl, javed.absar
Subscribers: rengolin, srhines, kubamracek, kristof.beyls, llvm-commits, cryptoad
Differential Revision: https://reviews.llvm.org/D47160
llvm-svn: 333025
Use libc++ when selected as default Clang stdlib and avoid checking
C++ compiler when using the in-tree version of libc++.
This is a partial alternative to D47094 that does not rely on compiler
runtime checks.
Differential Revision: https://reviews.llvm.org/D47100
llvm-svn: 333010
When using system C++ library, assume we have a working C++ compiler and
try to compile a complete C++ program. When using in tree C++ library,
only check the C compiler since the C++ library likely won't have been
built yet at time of running the check.
Differential Revision: https://reviews.llvm.org/D47169
llvm-svn: 332924
On RTEMS, system and user code all live in a single binary and address
space. There is no clean separation, and instrumented code may
execute before the ASan run-time is initialized (or after it has been
destroyed).
Currently, GetCurrentThread() may crash if it's called before ASan
run-time is initialized. Make it return nullptr instead.
Similarly, fix __asan_handle_no_return so that it gives up rather than
try something that may crash.
Differential Revision: https://reviews.llvm.org/D46459
llvm-svn: 332888
Summary:
The static TLS vector for the main thread on NetBSD/i386 can be
unaligned in terms of the shadow granularity. Align the start of it with
Round Down and end of it with Round Up operations for the shadow
granularity shift.
Example static TLS vector ranges on NetBSD/i386:
tls_begin_=0xfbee7244 tls_end_=0xfbee726c.
ClearShadowForThreadStackAndTLS() is called from the Main Thread
bootstrap functions.
This change restores the NetBSD x86 32-bit (i386) support.
Sponsored by <The NetBSD Foundation>
Reviewers: vitalybuka, joerg
Reviewed By: vitalybuka
Subscribers: kubamracek, llvm-commits, #sanitizers
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D46585
llvm-svn: 332792
Summary:
The changes allows building this file on NetBSD, mostly by
disabling the unsupported functions and adding OS-specific
system includes.
Sponsored by <The NetBSD Foundation>
Reviewers: joerg, kcc, vitalybuka
Reviewed By: vitalybuka
Subscribers: llvm-commits, #sanitizers
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D46712
llvm-svn: 332791
Summary:
Floating point division by zero or even undef does not have undefined
behavior and may occur due to optimizations.
Fixes https://bugs.llvm.org/show_bug.cgi?id=37523.
Reviewers: kcc
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D47085
llvm-svn: 332761
This is not needed after we've forked the Myriad version. Not to
mention it produces a compiler warning.
Differential Revision: https://reviews.llvm.org/D47054
llvm-svn: 332744
The Myriad RTEMS memory system has a few unique aspects that
require support in the ASan run-time.
- A limited amount of memory (currently 512M).
- No virtual memory, no memory protection.
- DRAM starts at address 0x80000000. Other parts of memory may be
used for MMIO, etc.
- The second highest address bit is the "cache" bit, and 0x80000000
and 0x84000000 alias to the same memory.
To support the above, we make the following changes:
- Use a ShadowScale of 5, to reduce shadow memory overhead.
- Adjust some existing macros to remove assumption that the lowest
memory address is 0.
- add a RawAddr macro that on Myriad strips the cache bit from the
input address, before using the address for shadow memory (for other
archs this does nothing).
- We must check that an address is in DRAM range before using it to
index into shadow memory.
Differential Revision: https://reviews.llvm.org/D46456
llvm-svn: 332690
Rather then requiring the user to specify runtime the compiler
runtime and C++ standard library, or trying to guess them which is
error-prone, use auto-detection by parsing the compiler link output.
Differential Revision: https://reviews.llvm.org/D46857
llvm-svn: 332683
This commit contains the trivial portion of the port of ASan to
Myriad RTEMS.
- Whitelist platform in sanitizer_platform.h, ubsan_platform.h
- Turn off general interception
- Use memset for FastPoisonShadow
- Define interception wrappers
- Set errno symbol correctly
- Enable ASAN_LOW_MEMORY
- Enable preinit array
- Disable slow unwinding
- Use fuchsia offline symbolizer
- Disable common code for: InitializeShadowMemory, CreateMainThread,
AsanThread::ThreadStart, StartReportDeadlySignal,
MaybeReportNonExecRegion.
Differential Revision: https://reviews.llvm.org/D46454
llvm-svn: 332681
The source being compiled is plain C, but using .cc extension forces it
to be compiled as C++ which requires a working C++ compiler including
C++ library which may not be the case when we're building compiler-rt
together with libcxx as part of runtimes build.
Differential Revision: https://reviews.llvm.org/D47031
llvm-svn: 332679
This gives us something to insert into the shadow gap for systems that
don't have memory protection turned on there (i.e. on Myriad).
Differential Revision: https://reviews.llvm.org/D46457
llvm-svn: 332557
Summary:
This can be solved just in seconds with KLEE. Current libFuzzer
is able to satistfy 101 constraints out of 410 constraints presented during
the first hour of running with -use_value_profile=1 and -max_len=20.
During the next 3 hours, libFuzzer is able to generate ~50 NEW inputs,
bot none of those solve any new constraint.
During the next 20 hours, it didn't find any NEW inputs.
This test might be interesting for experimenting with the data flow tracing
approach started in https://reviews.llvm.org/D46666.
For the solution with KLEE and other information, see
https://github.com/Dor1s/codegate2017-quals-angrybird
Reviewers: kcc
Reviewed By: kcc
Subscribers: delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D46924
llvm-svn: 332507
Summary:
It turns out that the previous code construct was not optimizing the allocation
and deallocation of batches. The class id was read as a class member (even
though a precomputed one) and nothing else was optimized. By changing the
construct this way, the compiler actually optimizes most of the allocation and
deallocation away to only work with a single class id, which not only saves some
CPU but also some code footprint.
Reviewers: alekseyshl, dvyukov
Reviewed By: dvyukov
Subscribers: dvyukov, delcypher, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D46961
llvm-svn: 332502
Summary:
For the 32-bit TransferBatch:
- `SetFromArray` callers have bounds `count`, so relax the `CHECK` to `DCHECK`;
- same for `Add`;
- mark `CopyToArray` as `const`;
For the 32-bit Primary:
- `{Dea,A}llocateBatch` are only called from places that check `class_id`,
relax the `CHECK` to `DCHECK`;
- same for `AllocateRegion`;
- remove `GetRegionBeginBySizeClass` that is not used;
- use a local variable for the random shuffle state, so that the compiler can
use a register instead of reading and writing to the `SizeClassInfo` at every
iteration;
For the 32-bit local cache:
- pass the count to drain instead of doing a `Min` everytime which is at times
superfluous.
Reviewers: alekseyshl
Reviewed By: alekseyshl
Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D46657
llvm-svn: 332478
Matt Morehouse