Commit Graph

6395 Commits

Author SHA1 Message Date
Dean Michael Berris e7dbebf182 [XRay][compiler-rt] XRay Flight Data Recorder Mode
Summary:
In this change we introduce the notion of a "flight data recorder" mode
for XRay logging, where XRay logs in-memory first, and write out data
on-demand as required (as opposed to the naive implementation that keeps
logging while tracing is "on"). This depends on D26232 where we
implement the core data structure for holding the buffers that threads
will be using to write out records of operation.

This implementation only currently works on x86_64 and depends heavily
on the TSC math to write out smaller records to the inmemory buffers.

Also, this implementation defines two different kinds of records with
different sizes (compared to the current naive implementation): a
MetadataRecord (16 bytes) and a FunctionRecord (8 bytes). MetadataRecord
entries are meant to write out information like the thread ID for which
the metadata record is defined for, whether the execution of a thread
moved to a different CPU, etc. while a FunctionRecord represents the
different kinds of function call entry/exit records we might encounter
in the course of a thread's execution along with a delta from the last
time the logging handler was called.

While this implementation is not exactly what is described in the
original XRay whitepaper, this one gives us an initial implementation
that we can iterate and build upon.

Reviewers: echristo, rSerge, majnemer

Subscribers: mehdi_amini, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D27038

llvm-svn: 293015
2017-01-25 03:50:46 +00:00
Kostya Serebryany 99259ee40c [asan] fix __sanitizer_cov_with_check to get the correct caller PC. Before this fix the code relied on the fact that the other function (__sanitizer_cov) is inlined. This was true with clang builds on x86, but not true with gcc builds on x86 and on PPC. This caused bot redness after r292862
llvm-svn: 292998
2017-01-25 01:14:24 +00:00
Kuba Mracek e4c1dd2c08 [tsan] Enable ignore_noninstrumented_modules=1 on Darwin by default
TSan recently got the "ignore_noninstrumented_modules" flag, which disables tracking of read and writes that come from noninstrumented modules (via interceptors). This is a way of suppressing false positives coming from system libraries and other noninstrumented code. This patch turns this on by default on Darwin, where it's supposed to replace the previous solution, "ignore_interceptors_accesses", which disables tracking in *all* interceptors. The new approach should re-enable TSan's ability to find races via interceptors on Darwin.

Differential Revision: https://reviews.llvm.org/D29041

llvm-svn: 292981
2017-01-24 21:37:50 +00:00
Reid Kleckner 310c3d3d26 Fix pc_array bounds check to use elements instead of bytes
pc_array_size and kPcArrayMaxSize appear to be measured in elements, not
bytes, so we shouldn't multiply idx by sizeof(uptr) in this bounds
check.  32-bit Chrome was tripping this assertion because it has 64
million coverage points. I don't think it's worth adding a test that has
that many coverage points.

llvm-svn: 292955
2017-01-24 17:45:35 +00:00
Bill Seurer f7e822534e [powerpc] deactivate ThreadedMallocStressTest asan test on powerpc64
This has not reliably worked on powerpc since r279664.  Re-enable this
once the problem is tracked down and fixed.

llvm-svn: 292945
2017-01-24 16:51:16 +00:00
Evgeniy Stepanov 0f550c8176 Revert "[lsan] Enable LSan for x86 Linux."
Breaks tests on i686/Linux due to missing clang driver support:
  error: unsupported option '-fsanitize=leak' for target 'i386-unknown-linux-gnu'

llvm-svn: 292844
2017-01-23 22:52:31 +00:00
Maxim Ostapenko 2523faf677 [lsan] Enable LSan for x86 Linux.
People keep asking LSan to be available on 32 bit targets (e.g. https://github.com/google/sanitizers/issues/403)
despite the fact that false negative ratio might be huge (up to 85%). This happens for big real world applications
that may contain random binary data (e.g. browser), but for smaller apps situation is not so terrible and LSan still might be useful.
This patch adds initial support for x86 Linux (disabled by default), ARM32 is in TODO list.
We used this patch (well, ported to GCC) on our 32 bit mobile emulators and it worked pretty fine
thus I'm posting it here to initiate further discussion.

Differential Revision: https://reviews.llvm.org/D28609

llvm-svn: 292775
2017-01-23 08:45:17 +00:00
Marcos Pividori 440e641566 Revert "[interception] Check for export table's size before referring to its elements."
This reverts commit r292747 because cmake fails for some archs.

llvm-svn: 292751
2017-01-22 03:30:14 +00:00
Marcos Pividori 4e12600c90 [interception] Check for export table's size before referring to its elements.
This fix a bug, when calling InternalGetProcAddress() for an executable that
doesn't export any symbol. So the table is empty.
If we don't check for this condition, the program fails with Error 0xc0000142.

Also, I add a regression test for Windows.

Differential Revision: https://reviews.llvm.org/D28502

llvm-svn: 292747
2017-01-22 02:14:57 +00:00
Weiming Zhao 19f47ace40 [Bultin][ARM] Make aeabi_memset be Thumb1 compatible and other asm
syntax fix

Summary:
Make the asm of  aeabi_memset be assembled for thumb1.
Also fix some instructions to conform with the syntax of ARM reference manual.
For example, muls requires the form of "Rd, Rn, Rd" and orrs requires
the form of "Rd, Rm". Clang-as is benign but it may fail other assembler
if not in the exact form.

Reviewers: rengolin, compnerd, kubamracek

Reviewed By: rengolin, compnerd

Subscribers: aemerson, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D28971

llvm-svn: 292727
2017-01-21 18:24:55 +00:00
Marcos Pividori 74694b19e0 [sanitizer] [asan] Use macros to simplify weak aliases on Windows.
This patch adds some useful macros for dealing with pragma directives on
Windows. Also, I add appropriate documentation for future users.

Differential Revision: https://reviews.llvm.org/D28525

llvm-svn: 292650
2017-01-20 21:09:36 +00:00
Kostya Kortchinsky a00b9229c3 [scudo] Replacing std::atomic with Sanitizer's atomics
Summary:
In an effort to getting rid of dependencies to external libraries, we are
replacing atomic PackedHeader use of std::atomic with Sanitizer's
atomic_uint64_t, which allows us to avoid -latomic.

Reviewers: kcc, phosek, alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28864

llvm-svn: 292630
2017-01-20 18:32:18 +00:00
Alex Shlyapnikov a8ba9c8e66 Whenever reasonable, merge ASAN quarantine batches to save memory.
Summary:
There are cases when thread local quarantine drains almost empty
quarantine batches into the global quarantine. The current approach leaves
them almost empty, which might create a huge memory overhead (each batch
is 4K/8K, depends on bitness).

Reviewers: eugenis

Subscribers: kubabrecka, llvm-commits

Differential Revision: https://reviews.llvm.org/D28068

llvm-svn: 292525
2017-01-19 22:15:54 +00:00
Serge Rogatch 9bce1e7553 [XRay][Arm] Enable back XRay testing on Arm32 and fix the failing tests
Summary:
Testing of XRay was occasionally disabled on 32-bit Arm targets (someone assumed that XRay was supported on 64-bit targets only). This patch should fix that problem. Also here the instruction&data cache incoherency problem is fixed, because it may be causing a test to fail.
This patch is one of a series: see also
- https://reviews.llvm.org/D28624

Reviewers: dberris, rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, aemerson, rengolin, dberris, iid_iunknown

Differential Revision: https://reviews.llvm.org/D28623

llvm-svn: 292517
2017-01-19 20:27:11 +00:00
Weiming Zhao 93b558a486 [Builtin] [ARM] Update CMake to support the build of armv6m
Summary:
Setting -DCOMPILER_RT_TEST_TARGET_TRIPLE=armv6m-none-eabi  will enable the build of builtin functions ARMv6m.
Currently, only those asms that support armv6m are added.

TODO:All asm sin ARM_EABI_Sources are ported for thumb1 so Thumb1_EABI_Sources will be deprecated.

Reviewers: rengolin, compnerd

Reviewed By: compnerd

Subscribers: aemerson, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D28463

llvm-svn: 292504
2017-01-19 18:46:11 +00:00
Kostya Kortchinsky b39dff4551 [scudo] Refactor of CRC32 and ARM runtime CRC32 detection
Summary:
ARM & AArch64 runtime detection for hardware support of CRC32 has been added
via check of the AT_HWVAL auxiliary vector.

Following Michal's suggestions in D28417, the CRC32 code has been further
changed and looks better now. When compiled with full relro (which is strongly
suggested to benefit from additional hardening), the weak symbol for
computeHardwareCRC32 is read-only and the assembly generated is fairly clean
and straight forward. As suggested, an additional optimization is to skip
the runtime check if SSE 4.2 has been enabled globally, as opposed to only
for scudo_crc32.cpp.

scudo_crc32.h has no purpose anymore and was removed.

Reviewers: alekseyshl, kcc, rengolin, mgorny, phosek

Reviewed By: rengolin, mgorny

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: https://reviews.llvm.org/D28574

llvm-svn: 292409
2017-01-18 17:11:17 +00:00
Renato Golin 8f03fbe678 Revert "[XRay][Arm] Enable back XRay testing on Arm32 and fix the failing tests"
This reverts commit r292211, as it broke the Thumb buldbot with:

clang-5.0: error: the clang compiler does not support '-fxray-instrument
on thumbv7-unknown-linux-gnueabihf'

llvm-svn: 292356
2017-01-18 09:07:35 +00:00
Petr Hosek 97ab7fe6b7 [scudo] Eliminate the runtime dependency on libc++abi
Making this variable non-static avoids the need for locking to ensure
that the initialization is thread-safe which in turns eliminates the
runtime dependency on libc++abi library (for __cxa_guard_acquire and
__cxa_guard_release) which makes it possible to link scudo against
pure C programs.

Differential Revision: https://reviews.llvm.org/D28757

llvm-svn: 292253
2017-01-17 20:41:04 +00:00
Serge Rogatch 1bcd53f0e7 [XRay][Arm] Enable back XRay testing on Arm32 and fix the failing tests
Summary:
Testing of XRay was occasionally disabled on 32-bit Arm targets (someone assumed that XRay was supported on 64-bit targets only). This patch should fix that problem. Also here the instruction&data cache incoherency problem is fixed, because it may be causing a test to fail.
This patch is one of a series: see also
- https://reviews.llvm.org/D28624

Reviewers: dberris, rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, aemerson, rengolin, dberris, iid_iunknown

Differential Revision: https://reviews.llvm.org/D28623

llvm-svn: 292211
2017-01-17 11:53:38 +00:00
Reid Kleckner c397aff091 Remove SANITIZER_LINUX ifdefs
Somehow this causes lots of test failures on Windows. These appear to
have been accidentally added back in r291736.

llvm-svn: 291947
2017-01-13 19:25:58 +00:00
Alex Shlyapnikov c4427a3976 ASAN activate/deactive controls thread_local_quarantine_size_kb option.
Summary:
Bypass quarantine altogether when quarantine size is set ot zero.
Also, relax atomic load/store of quarantine parameters, the
release/acquire semantics is an overkill here.

Reviewers: eugenis

Subscribers: kubabrecka, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D28586

llvm-svn: 291791
2017-01-12 18:51:25 +00:00
Mike Aizatsky 9700acba11 Revert "[sancov] moving sancov rt to sancov/ directory"
This reverts commit https://reviews.llvm.org/rL291734
Reason: mac breakage
http://lab.llvm.org:8080/green//job/clang-stage1-configure-RA_build/28798/consoleFull#1657087648e9a0fee5-ebcc-4238-a641-c5aa112c323e

llvm-svn: 291736
2017-01-12 01:37:35 +00:00
Mike Aizatsky fc05471ec2 [sancov] there are windows tests that check linker symbols
llvm-svn: 291735
2017-01-12 01:35:26 +00:00
Mike Aizatsky 875572f358 [sancov] moving sancov rt to sancov/ directory
Subscribers: kubabrecka, mgorny

Differential Revision: https://reviews.llvm.org/D28541

llvm-svn: 291734
2017-01-12 01:19:34 +00:00
Alex Shlyapnikov c83efa85e2 Repoison the entire ASan chunk if it is not in active use.
Summary:
Repoisoning just the minimal redzones might leave an unpoisoned
gap of the size of the actual redzone minus minimal redzone size.
After ASan activation the actual redzone might be bigger than the minimal
size and ASan allocator assumes that the chunk returned by the common
allocator is either entirely poisoned or entirely not poisoned (it's too
expensive to check the entire chunk or always poison one).

Reviewers: eugenis

Subscribers: kubabrecka, llvm-commits

Differential Revision: https://reviews.llvm.org/D28577

llvm-svn: 291714
2017-01-11 22:10:35 +00:00
Saleem Abdulrasool 9c287bca23 builtins: support building ARM builtins for a HF target
The `-target` impacts the CC for the builtins.  HF targets (with either
floating point ABI) always use AAPCS VFP for the builtins unless they
are AEABI builtins, in which case they use AAPCS.  Non-HF targets (with
either floating point ABI) always use AAPCS for the builtins and AAPCS
for the AEABI builtins.  This introduces the thunks necessary to switch
CC for the floating point operations.  This is not currently enabled,
and should be dependent on the target being used to build compiler-rt.
However, as a stop-gap, a define can be added for ASFLAGS to get the
thunks.

llvm-svn: 291677
2017-01-11 16:19:25 +00:00
Kuba Mracek 14cabdd2c3 Follow-up for r291277: Add a return to silence GCC's "control reaches end of non-void function" warning.
llvm-svn: 291639
2017-01-11 01:12:53 +00:00
Kuba Mracek e7709560ea [tsan] Implement a 'ignore_noninstrumented_modules' flag to better suppress false positive races
On Darwin, we currently use 'ignore_interceptors_accesses', which is a heavy-weight solution that simply turns of race detection in all interceptors. This was done to suppress false positives coming from system libraries (non-instrumented code), but it also silences a lot of real races. This patch implements an alternative approach that should allow us to enable interceptors and report races coming from them, but only if they are called directly from instrumented code.

The patch matches the caller PC in each interceptors. For non-instrumented code, we call ThreadIgnoreBegin.

The assumption here is that the number of instrumented modules is low. Most likely there's only one (the instrumented main executable) and all the other modules are system libraries (non-instrumented).

Differential Revision: https://reviews.llvm.org/D28264

llvm-svn: 291631
2017-01-11 00:54:26 +00:00
Saleem Abdulrasool 7a0838b9b6 builtins: repair __gtsf2 after SVN r291396
The argument adjustment was accidentally removed, resulting in the use
of stale register values.

llvm-svn: 291591
2017-01-10 19:48:50 +00:00
Kostya Kortchinsky c4d6c938e3 [scudo] Separate hardware CRC32 routines
Summary:
As raised in D28304, enabling SSE 4.2 for the whole Scudo tree leads to the
emission of SSE 4.2 instructions everywhere, while the runtime checks only
applied to the CRC32 computing function.

This patch separates the CRC32 function taking advantage of the hardware into
its own file, and only enabled -msse4.2 for that file, if detected to be
supported by the compiler.

Another consequence of removing SSE4.2 globally is realizing that memcpy were
not being optimized, which turned out to be due to the -fno-builtin in
SANITIZER_COMMON_CFLAGS. So we now explicitely enable builtins for Scudo.

The resulting assembly looks good, with some CALLs are introduced instead of
the CRC32 code being inlined.

Reviewers: kcc, mgorny, alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28417

llvm-svn: 291570
2017-01-10 16:39:36 +00:00
Serge Rogatch 4ab7a30538 [XRay][AArch64] An attempt to fix test patching-unpatching.cc by flushing the instruction cache after code modification
Summary: This patch attempts to fix test patching-unpatching.cc . The new code flushes the instruction cache after modifying the program at runtime.

Reviewers: dberris, rengolin, pelikan, rovka

Subscribers: rovka, llvm-commits, iid_iunknown, aemerson

Differential Revision: https://reviews.llvm.org/D27996

llvm-svn: 291568
2017-01-10 16:16:33 +00:00
Maxim Ostapenko 0f0407331e [sanitizer] Fix sigaction definition on 32-bit sparc
Patch by James Clarke.

Differential Revision: https://reviews.llvm.org/D28309

llvm-svn: 291561
2017-01-10 12:41:18 +00:00
Diana Picus c1e2ab3626 Revert r291509, 291510 and 291511
Revert "ASAN activate/deactive controls thread_local_quarantine_size_kb option."
Revert "Bypass quarantine when quarantine size is set ot zero."
Revert "ASAN activate/deactive controls thread_local_quarantine_size_kb option."

One of these commits broke some of the ARM / AArch64 buildbots:
TEST 'AddressSanitizer-aarch64-linux :: TestCases/Posix/start-deactivated.cc' FAILED

Command Output (stderr):
--
/home/buildslave/buildslave/clang-cmake-aarch64-42vma/llvm/projects/compiler-rt/test/asan/TestCases/Posix/start-deactivated.cc:85:12: error: expected string not found in input
 // CHECK: WARNING: AddressSanitizer failed to allocate 0xfff{{.*}} bytes
           ^
<stdin>:1:1: note: scanning from here
start-deactivated.cc.tmp: /home/buildslave/buildslave/clang-cmake-aarch64-42vma/llvm/projects/compiler-rt/test/asan/TestCases/Posix/start-deactivated.cc:40: void test_malloc_shadow(char *, size_t, bool): Assertion `(char *)__asan_region_is_poisoned(p - 1, sz + 1) == (expect_redzones ? p - 1 : nullptr)' failed.
^
<stdin>:2:1: note: possible intended match here
Error: Aborted (core dumped)
^

llvm-svn: 291560
2017-01-10 11:14:44 +00:00
Francis Ricci 17781c71b0 Make cmake link flag naming consistent
Summary:
The build system was inconsistent in its naming conventions for
link flags. This patch changes all uses of LINKFLAGS to LINK_FLAGS,
for consistency with cmake's LINK_FLAGS property.

This patch should make it easier to search the source code for
uses of link flags, as well as providing the benefit of improved
style and consistency.

Reviewers: compnerd, beanz

Subscribers: kubabrecka, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D28506

llvm-svn: 291539
2017-01-10 04:33:04 +00:00
Alex Shlyapnikov 0e93c3932a ASAN activate/deactive controls thread_local_quarantine_size_kb option.
Summary: Also, bypass quarantine altogether when quarantine size is set ot zero.

Reviewers: eugenis

Subscribers: kubabrecka, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D28480

llvm-svn: 291511
2017-01-09 23:49:17 +00:00
Alex Shlyapnikov 518acec990 Bypass quarantine when quarantine size is set ot zero.
llvm-svn: 291510
2017-01-09 23:49:15 +00:00
Alex Shlyapnikov ae8e9bbb2c ASAN activate/deactive controls thread_local_quarantine_size_kb option.
llvm-svn: 291509
2017-01-09 23:49:13 +00:00
Kuba Mracek ca6d868f14 [compiler-rt] Include <dlfcn.h> unconditionally
This fixes a build issue with musl-libc.

Differential Revision: https://reviews.llvm.org/D21656

llvm-svn: 291454
2017-01-09 17:39:31 +00:00
Francis Ricci ff567a8ba2 Enable weak hooks on darwin
Summary:
By default, darwin requires a definition for weak interface functions at
link time. Adding the '-U' link flag with each weak function allows these
weak interface functions to be used without definitions, which mirrors
behavior on linux and windows.

Reviewers: compnerd, eugenis

Subscribers: kubabrecka, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D28203

llvm-svn: 291417
2017-01-09 03:51:42 +00:00
Weiming Zhao ccd3e6803c [Builtins] [ARM] Adding Thumb1 support for fcmp
Summary: Mainly translate IT block into cmp/branch for functions in comparesf2.S

Reviewers: rengolin, compnerd

Subscribers: aemerson, llvm-commits

Differential Revision: https://reviews.llvm.org/D28016

llvm-svn: 291396
2017-01-08 18:51:12 +00:00
Dmitry Vyukov ffff5f16a4 tsan: Introducing a function to flush the shadow memory from third-party libraries
As discussed with Dmitry (https://goo.gl/SA4izd), I would like to introduce a function to be called from a third-party library to flush the shadow memory.
In particular, we ran some experiments with our tool Archer (an OpenMP data race detector based on Tsan, https://github.com/PRUNER/archer) and flushing the memory at the end of an outer parallel region, slightly increase the runtime overhead, but reduce the memory overhead of about 30%. This feature would come very handy in case of very large OpenMP applications that may cause an "out of memory" exception when checked with Tsan.

Reviewed in: https://reviews.llvm.org/D28443
Author: Simone Atzeni (simoatze)

llvm-svn: 291346
2017-01-07 11:27:33 +00:00
Francis Ricci fcde2a708f Revert "Enable weak hooks on darwin"
Reverts accidental upload.

This reverts commit 421408c0f2cc811bcf9a945be6e95e46f76cb358.

llvm-svn: 291316
2017-01-07 00:38:24 +00:00
Francis Ricci 1d35775379 Enable weak hooks on darwin
Summary:
By default, darwin requires a definition for weak interface functions at
link time. Adding the '-U' link flag with each weak function allows these
weak interface functions to be used without definitions, which mirrors
behavior on linux and windows.

Reviewers: compnerd, eugenis

Subscribers: kubabrecka, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D28203

llvm-svn: 291314
2017-01-07 00:31:24 +00:00
Francis Ricci 9a2a9922ca Provide default implementations for sanitizer interface functions
Summary:
Adds a few default implementations for weak
interface functions on platforms where weak hooks are not supported.

Reviewers: eugenis, samsonov, timurrrr

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28201

llvm-svn: 291313
2017-01-07 00:31:20 +00:00
Francis Ricci 1fb895e890 Ensure that only one compiler-rt component is created for lsan
Summary:
The lsan cmake configuration failed when targeting more
than one architecture, because it would attempt to create multiple
components with the same name. Ensure that only one lsan component
is ever created.

Reviewers: beanz, bogner

Subscribers: dberris, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D28151

llvm-svn: 291294
2017-01-06 22:45:49 +00:00
Kuba Mracek b38f1ca2d5 [sanitizer] Use architecture/slice information when symbolizing fat Mach-O files on Darwin
This patch starts passing architecture information about a module to llvm-symbolizer and into text reports. This fixes the longstanding x86_64/x86_64h mismatch issue on Darwin.

Differential Revision: https://reviews.llvm.org/D27390

llvm-svn: 291287
2017-01-06 21:45:05 +00:00
Kuba Mracek 218ecacbf1 [asan] Teach asan_symbolize.py to use :arch with atos and llvm-symbolizer on Darwin
This patch teaches asan_symbolize.py to read an architecture suffix on module names (e.g. ":x86_64") and pass that option to atos and llvm-symbolizer.

Differential Revision: https://reviews.llvm.org/D27378

llvm-svn: 291280
2017-01-06 21:02:50 +00:00
Kuba Mracek b6c6eaf226 [sanitizer] Add a 'print_module_map' flag which prints modules with UUIDs on Darwin
This patch add a new sanitizer flag, print_module_map, which enables printing a module map when the process exits, or after each report (for TSan). The output format is very similar to what Crash Reporter produces on Darwin (e.g. the format of module UUIDs). This enables users to use the existing symbol servers to offline symbolicate and aggregate reports.

Differential Revision: https://reviews.llvm.org/D27400

llvm-svn: 291277
2017-01-06 20:57:47 +00:00
Kuba Mracek 43d287e04e [sanitizer] Track which modules are instrumented in LoadedModule objects
This patch adds tracking which modules are instrumented and which are not. On macOS, instrumented modules link against the ASan/TSan/... dylib, so we can just check if such a load command exists or not.

Differential Revision: https://reviews.llvm.org/D28263

llvm-svn: 291268
2017-01-06 19:34:54 +00:00
Mike Aizatsky fb96e04efb [sancov] introducing SANCOV_OPTIONS
Reintroducing https://reviews.llvm.org/rL291068
Define options function everywhere but linux.

llvm-svn: 291267
2017-01-06 19:22:50 +00:00