Commit Graph

128 Commits

Author SHA1 Message Date
Dmitry Vyukov 5dc443619e tsan: always define SANITIZER_GO
Currently we either define SANITIZER_GO for Go or don't define it at all for C++.
This works fine with preprocessor (ifdef/ifndef/defined), but does not work
for C++ if statements (e.g. if (SANITIZER_GO) {...}). Also this is different
from majority of SANITIZER_FOO macros which are always defined to either 0 or 1.

Always define SANITIZER_GO to either 0 or 1.
This allows to use SANITIZER_GO in expressions and in flag default values.

Also remove kGoMode and kCppMode, which were meant to be used in expressions,
but they are not defined in sanitizer_common code, so SANITIZER_GO become prevalent.

Also convert some preprocessor checks to C++ if's or ternary expressions.

Majority of this change is done mechanically with:
sed "s#ifdef SANITIZER_GO#if SANITIZER_GO#g"
sed "s#ifndef SANITIZER_GO#if \!SANITIZER_GO#g"
sed "s#defined(SANITIZER_GO)#SANITIZER_GO#g"

llvm-svn: 285443
2016-10-28 20:14:18 +00:00
Dmitry Vyukov a386ac6367 tsan: make CHECK more robust
Enable more ignores when we start crashing.
Unwind in CHECK SIGSEGVs if happens early:

FATAL: ThreadSanitizer CHECK failed: ../projects/compiler-rt/lib/tsan/rtl/tsan_platform_posix.cc:105 "((beg)) <= ((end))" (0x8000000000, 0x4000000000)
Program received signal SIGSEGV, Segmentation fault.
__tsan::MetaMap::GetAndLock (this=0x1337c88 <__tsan::ctx_placeholder+8>, thr=thr@entry=0x7ffff7f91800, pc=pc@entry=4639488, addr=addr@entry=140737339086992, write_lock=write_lock@entry=true, 
    create=create@entry=true) at ../projects/compiler-rt/lib/tsan/rtl/tsan_sync.cc:208
208	  u32 idx0 = *meta;
(gdb) bt
#0  __tsan::MetaMap::GetAndLock (this=0x1337c88 <__tsan::ctx_placeholder+8>, thr=thr@entry=0x7ffff7f91800, pc=pc@entry=4639488, addr=addr@entry=140737339086992, write_lock=write_lock@entry=true, 
    create=create@entry=true) at ../projects/compiler-rt/lib/tsan/rtl/tsan_sync.cc:208
#1  0x00000000004a965f in __tsan::MetaMap::GetOrCreateAndLock (this=<optimized out>, thr=thr@entry=0x7ffff7f91800, pc=pc@entry=4639488, addr=addr@entry=140737339086992, write_lock=write_lock@entry=true)
    at ../projects/compiler-rt/lib/tsan/rtl/tsan_sync.cc:198
#2  0x00000000004a162a in __tsan::Release (thr=0x7ffff7f91800, pc=pc@entry=4639488, addr=addr@entry=140737339086992) at ../projects/compiler-rt/lib/tsan/rtl/tsan_rtl_mutex.cc:395
#3  0x000000000046cc40 in __interceptor_pthread_once (o=0x7ffff71a5890 <once_regsizes>, f=0x7ffff6f9d9c0 <init_dwarf_reg_size_table>) at ../projects/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc:1334
#4  0x00007ffff6f9fe86 in __gthread_once (__func=0x7ffff6f9d9c0 <init_dwarf_reg_size_table>, __once=0x7ffff71a5890 <once_regsizes>) at ./gthr-default.h:699
#5  uw_init_context_1 (context=context@entry=0x7fffffffd6d0, outer_cfa=outer_cfa@entry=0x7fffffffd980, outer_ra=0x437d13 <__sanitizer::BufferedStackTrace::SlowUnwindStack(unsigned long, unsigned int)+67>)
    at ../../../src/libgcc/unwind-dw2.c:1572
#6  0x00007ffff6fa06a8 in _Unwind_Backtrace (trace=0x437c30 <__sanitizer::Unwind_Trace(_Unwind_Context*, void*)>, trace_argument=0x7fffffffd980) at ../../../src/libgcc/unwind.inc:283
#7  0x0000000000437d13 in __sanitizer::BufferedStackTrace::SlowUnwindStack (this=0x7ffff6103208, pc=pc@entry=4863574, max_depth=max_depth@entry=256)
    at ../projects/compiler-rt/lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc:125
#8  0x0000000000434f4a in __sanitizer::BufferedStackTrace::Unwind (this=this@entry=0x7ffff6103208, max_depth=max_depth@entry=256, pc=pc@entry=4863574, bp=bp@entry=0, context=context@entry=0x0, 
    stack_top=stack_top@entry=0, stack_bottom=stack_bottom@entry=0, request_fast_unwind=request_fast_unwind@entry=false) at ../projects/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_libcdep.cc:76
#9  0x00000000004a36b3 in PrintCurrentStackSlow (pc=4863574) at ../projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cc:696
#10 __tsan::TsanCheckFailed (file=<optimized out>, line=<optimized out>, cond=<optimized out>, v1=<optimized out>, v2=<optimized out>) at ../projects/compiler-rt/lib/tsan/rtl/tsan_rtl_report.cc:44
#11 0x000000000042dfd6 in __sanitizer::CheckFailed (file=file@entry=0x4b9fd0 "../projects/compiler-rt/lib/tsan/rtl/tsan_platform_posix.cc", line=line@entry=105, 
    cond=cond@entry=0x4ba049 "((beg)) <= ((end))", v1=v1@entry=549755813888, v2=v2@entry=274877906944) at ../projects/compiler-rt/lib/sanitizer_common/sanitizer_termination.cc:79
#12 0x00000000004aa36c in ProtectRange (end=274877906944, beg=549755813888) at ../projects/compiler-rt/lib/tsan/rtl/tsan_platform_posix.cc:105
#13 __tsan::CheckAndProtect () at ../projects/compiler-rt/lib/tsan/rtl/tsan_platform_posix.cc:133
#14 0x00000000004a9e95 in __tsan::InitializePlatform () at ../projects/compiler-rt/lib/tsan/rtl/tsan_platform_linux.cc:280
#15 0x0000000000497e73 in __tsan::Initialize (thr=0x7ffff7f91800) at ../projects/compiler-rt/lib/tsan/rtl/tsan_rtl.cc:343
#16 0x00007ffff7dea25a in _dl_init (main_map=0x7ffff7ffe1c8, argc=1, argv=0x7fffffffdb88, env=0x7fffffffdb98) at dl-init.c:111
#17 0x00007ffff7ddb30a in _dl_start_user () at rtld.c:871

llvm-svn: 281969
2016-09-20 13:28:20 +00:00
Dmitry Vyukov b3a51bdcd7 tsan: don't create sync objects on acquire
Creating sync objects on acquire is pointless:
acquire of a just created sync object if a no-op.

llvm-svn: 273862
2016-06-27 11:14:59 +00:00
Kuba Brecka bf8b5f8dd2 [tsan] Rename ReportThread->pid to ReportThread->os_id
The field "pid" in ReportThread is used to store the OS-provided thread ID (pthread_self or gettid). The name "pid" suggests it's a process ID, which it isn't. Let's rename it.

Differential Revision: http://reviews.llvm.org/D19365

llvm-svn: 266994
2016-04-21 14:49:25 +00:00
Chuang-Yu Cheng e480455fd6 Always inlining PrintCurrentStackSlow of tsan library to fix tail-call issue
The real problem is that sanitizer_print_stack_trace obtains current PC and
expects the PC to be in the stack trace after function calls. We don't
prevent tail calls in sanitizer runtimes, so this assumption does not
necessary hold.

We add "always inline" attribute on PrintCurrentStackSlow to address this
issue, however this solution is not reliable enough, but unfortunately, we
don't see any simple, reliable solution.

Reviewers: samsonov hfinkel kbarton tjablin dvyukov kcc

http://reviews.llvm.org/D19148

Thanks Hal, dvyukov, and kcc for invaluable discussion, I have even borrowed
part of dvyukov's summary as my commit message!

llvm-svn: 266869
2016-04-20 10:28:41 +00:00
Kuba Brecka a1496f7c37 [tsan] Add TSan debugger APIs
Currently, TSan only reports everything in a formatted textual form. The idea behind this patch is to provide a consistent API that can be used to query information contained in a TSan-produced report. User can use these APIs either in a debugger (via a script or directly), or they can use it directly from the process (e.g. in the __tsan_on_report callback). ASan already has a similar API, see http://reviews.llvm.org/D4466.

Differential Revision: http://reviews.llvm.org/D16191

llvm-svn: 263126
2016-03-10 17:00:29 +00:00
Dmitry Vyukov a029b79e1a tsan: describe heap/data locations in Go
llvm-svn: 262343
2016-03-01 15:38:12 +00:00
Alexey Samsonov 9c54984d43 [TSan] Try harder to avoid compiler-generated memset calls.
check_memcpy test added in r254959 fails on some configurations due to
memset() calls inserted by Clang. Try harder to avoid them:
* Explicitly use internal_memset() instead of empty braced-initializer.
* Replace "new T()" with "new T", as the former generates zero-initialization
  for structs in C++11.

llvm-svn: 255136
2015-12-09 18:48:10 +00:00
Kuba Brecka 6fd0675925 [tsan] Fix weakly imported functions on OS X
On OS X, for weak function (that user can override by providing their own implementation in the main binary), we need extern `"C" SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE NOINLINE`.

Fixes a broken test case on OS X, java_symbolization.cc, which uses a weak function __tsan_symbolize_external.

Differential Revision: http://reviews.llvm.org/D14907

llvm-svn: 254298
2015-11-30 13:27:18 +00:00
Kuba Brecka 11d8c1f8dd [tsan] Fix an assertion failure in FindThreadByUidLocked with recycled threads
When a race on file descriptors is detected, `FindThreadByUidLocked()` is called to retrieve ThreadContext with a specific unique_id. However, this ThreadContext might not exist in the thread registry anymore (it may have been recycled), in which case `FindThreadByUidLocked` will cause an assertion failure in `GetThreadLocked`. Adding a test case that reproduces this, producing:

    FATAL: ThreadSanitizer CHECK failed: sanitizer_common/sanitizer_thread_registry.h:92 "((tid)) < ((n_contexts_))" (0x34, 0x34)

This patch fixes this by replacing the loop with `FindThreadContextLocked`.

Differential Revision: http://reviews.llvm.org/D14984

llvm-svn: 254223
2015-11-28 09:16:34 +00:00
Dmitry Vyukov 3464dac0ca tsan: speed up race deduplication
Race deduplication code proved to be a performance bottleneck in the past if suppressions/annotations are used, or just some races left unaddressed. And we still get user complaints about this:
https://groups.google.com/forum/#!topic/thread-sanitizer/hB0WyiTI4e4
ReportRace already has several layers of caching for racy pcs/addresses to make deduplication faster. However, ReportRace still takes a global mutex (ThreadRegistry and ReportMutex) during deduplication and also calls mmap/munmap (which take process-wide semaphore in kernel), this makes deduplication non-scalable.

This patch moves race deduplication outside of global mutexes and also removes all mmap/munmap calls.
As the result, race_stress.cc with 100 threads and 10000 iterations become 30x faster:

before:
real	0m21.673s
user	0m5.932s
sys	0m34.885s

after:
real	0m0.720s
user	0m23.646s
sys	0m1.254s

http://reviews.llvm.org/D12554

llvm-svn: 246758
2015-09-03 11:20:46 +00:00
Alexey Samsonov eb4fe7883f [TSan] Support __sanitizer_set_death_callback().
llvm-svn: 245776
2015-08-22 01:07:02 +00:00
Alexey Samsonov bb79b06f4e [Sanitizers] Unify the semantics and usage of "exitcode" runtime flag across all sanitizers.
Summary:
Merge "exitcode" flag from ASan, LSan, TSan and "exit_code" from MSan
into one entity. Additionally, make sure sanitizer_common now uses the
value of common_flags()->exitcode when dying on error, so that this
flag will automatically work for other sanitizers (UBSan and DFSan) as
well.

User-visible changes:
* "exit_code" MSan runtime flag is now deprecated. If explicitly
  specified, this flag will take precedence over "exitcode".
  The users are encouraged to migrate to the new version.
* __asan_set_error_exit_code() and __msan_set_exit_code() functions
  are removed. With few exceptions, we don't support changing runtime
  flags during program execution - we can't make them thread-safe.
  The users should use __sanitizer_set_death_callback()
  that would call _exit() with proper exit code instead.
* Plugin tools (LSan and UBSan) now inherit the exit code of the parent
  tool. In particular, this means that ASan would now crash the program
  with exit code "1" instead of "23" if it detects leaks.

Reviewers: kcc, eugenis

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12120

llvm-svn: 245734
2015-08-21 20:49:37 +00:00
Dmitry Vyukov 7830c2d726 tsan: don't report any bugs when report_bugs=0 flag is set
llvm-svn: 245720
2015-08-21 18:21:24 +00:00
Dmitry Vyukov 6aaedb0829 tsan: always subtract one from program counters
Go has a pending change to pass proper PCs to tsan:
https://go-review.googlesource.com/#/c/4902/
So now we can always subtract one from PCs.

llvm-svn: 229262
2015-02-14 16:06:22 +00:00
Dmitry Vyukov 10070626b7 tsan: fix style
Usually we roll the variable declaration into the condition in cases like this.

llvm-svn: 224755
2014-12-23 07:21:23 +00:00
Dmitry Vyukov 8f9911b571 tsan: fix debugging output
llvm-svn: 224701
2014-12-22 12:31:32 +00:00
Dmitry Vyukov e1881269f8 tsan: don't crash with NULL deref during reporting
tctx==NULL crash observed during deadlock reporting.
There seems to be some bugs in the deadlock detector,
but it is still useful to be more robust during reporting.

llvm-svn: 224508
2014-12-18 10:19:32 +00:00
Dmitry Vyukov 4bde5c42b0 tsan: don't subtract one from fake PCs
These are fake and not actual PCs, more like function IDs.
Pass them to external symbolizer untouched.

llvm-svn: 224022
2014-12-11 16:12:16 +00:00
Kostya Serebryany 83ed889bbd [tsan] remove TSAN_GO in favor of SANITIZER_GO
llvm-svn: 223732
2014-12-09 01:31:14 +00:00
Alexey Samsonov 0e90668f14 Simplify Symbolizer::SymbolizePC() interface.
Return a linked list of AddressInfo objects, instead of using an array of
these objects as an output parameter. This simplifies the code in callers
of this function (especially TSan).

Fix a few memory leaks from internal allocator, when the returned
AddressInfo objects were not properly cleared.

llvm-svn: 223145
2014-12-02 19:48:40 +00:00
Alexey Samsonov fbaaed6b58 [Sanitizer] Introduce "stack_trace_format" runtime flag.
This flag can be used to specify the format of stack frames - user
can now provide a string with placeholders, which should be printed
for each stack frame with placeholders replaced with actual data.
For example "%p" will be replaced by PC, "%s" will be replaced by
the source file name etc.

"DEFAULT" value enforces default stack trace format currently used in
all the sanitizers except TSan.

This change also implements __sanitizer_print_stack_trace interface
function in TSan.

llvm-svn: 221469
2014-11-06 18:43:45 +00:00
Alexey Samsonov 860a1abf1d [TSan] Refactor/simplify ReportLocation structure.
# Make DataInfo (describing a global) a member of ReportLocation
    to avoid unnecessary copies and allocations.
  # Introduce a constructor and a factory method, so that
    all structure users don't have to go to internal allocator directly.
  # Remove unused fields (file/line).

No functionality change.

llvm-svn: 221302
2014-11-04 22:07:57 +00:00
Alexey Samsonov e3754634c0 [TSan] Make ReportStack contain __sanitizer::AddressInfo object.
AddressInfo contains the results of symbolization. Store this object
directly in the symbolized stack, instead of copying data around and
making unnecessary memory allocations.

No functionality change.

llvm-svn: 221294
2014-11-04 20:52:37 +00:00
Alexey Samsonov 3931dca7ec [TSan] Keep original function and filename in ReportStack.
TSan used to do the following transformations with data obtained
from the symbolizer:
1) Strip "__interceptor_" prefix from function name.
2) Use "strip_path_prefix" runtime flag to strip filepath.

Now these transformations are performed right before the stack trace
is printed, and ReportStack structure contains original information.

This seems like a right thing to do - stripping is a detail of report
formatting implementation, and should belong there. We should, for
example, use original path to source file when we apply suppressions.

This change also make "strip_path_prefix" flag behavior in TSan
consistent with all the other sanitizers - now it should actually
match *the prefix* of path, not some substring. E.g. earlier TSan
would turn "/usr/lib/libfoo.so" into "libfoo.so" even if strip_path_prefix
was "/lib/".

Finally, strings obtained from symbolizer come from internal allocator,
and "stripping" them early by incrementing a "char*" ensures they can
never be properly deallocated, which is a bug.

llvm-svn: 221283
2014-11-04 18:41:38 +00:00
Alexey Samsonov 40733a8024 [TSan] Use StackTrace from sanitizer_common where applicable
Summary:
This change removes `__tsan::StackTrace` class. There are
now three alternatives:
  # Lightweight `__sanitizer::StackTrace`, which doesn't own a buffer
  of PCs. It is used in functions that need stack traces in read-only
  mode, and helps to prevent unnecessary allocations/copies (e.g.
  for StackTraces fetched from StackDepot).
  # `__sanitizer::BufferedStackTrace`, which stores buffer of PCs in
  a constant array. It is used in TraceHeader (non-Go version)
  # `__tsan::VarSizeStackTrace`, which owns buffer of PCs, dynamically
  allocated via TSan internal allocator.

Test Plan: compiler-rt test suite

Reviewers: dvyukov, kcc

Reviewed By: kcc

Subscribers: llvm-commits, kcc

Differential Revision: http://reviews.llvm.org/D6004

llvm-svn: 221194
2014-11-03 22:23:44 +00:00
Alexey Samsonov 9c85927012 [Sanitizer] Make StackTrace a lightweight reference to array of PCs, and
introduce a BufferedStackTrace class, which owns this array.

Summary:
This change splits __sanitizer::StackTrace class into a lightweight
__sanitizer::StackTrace, which doesn't own array of PCs, and BufferedStackTrace,
which owns it. This would allow us to simplify the interface of StackDepot,
and eventually merge __sanitizer::StackTrace with __tsan::StackTrace.

Test Plan: regression test suite.

Reviewers: kcc, dvyukov

Reviewed By: dvyukov

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5985

llvm-svn: 220635
2014-10-26 03:35:14 +00:00
Dmitry Vyukov 02ff8bb986 tsan: better reporting for virtual-call-after-free
Previously we said that it's a data race, which is confusing
if it happens in the same thread.

llvm-svn: 219600
2014-10-13 08:46:25 +00:00
Alexey Samsonov 5c825967ea [TSan] Use common flags in the same way as all the other sanitizers
llvm-svn: 217559
2014-09-10 23:08:06 +00:00
Dmitry Vyukov 1015f8d753 tsan: remove special handling of false reports coming from JVM
There is now a more common functionality in the form of called_from_lib suppressions.

llvm-svn: 213057
2014-07-15 09:38:30 +00:00
Dmitry Vyukov 48b00fe8f9 tsan: remove compat mapping
There are no known usages anymore, so one less thing to support.

llvm-svn: 213056
2014-07-15 09:31:29 +00:00
Dmitry Vyukov bde4c9c773 tsan: refactor storage of meta information for heap blocks and sync objects
The new storage (MetaMap) is based on direct shadow (instead of a hashmap + per-block lists).
This solves a number of problems:
 - eliminates quadratic behaviour in SyncTab::GetAndLock (https://code.google.com/p/thread-sanitizer/issues/detail?id=26)
 - eliminates contention in SyncTab
 - eliminates contention in internal allocator during allocation of sync objects
 - removes a bunch of ad-hoc code in java interface
 - reduces java shadow from 2x to 1/2x
 - allows to memorize heap block meta info for Java and Go
 - allows to cleanup sync object meta info for Go
 - which in turn enabled deadlock detector for Go

llvm-svn: 209810
2014-05-29 13:50:54 +00:00
Dmitry Vyukov a43e98cc74 tsan: refactor suppressions machinery
The refactoring makes suppressions more flexible
and allow to suppress based on arbitrary number of stacks.
In particular it fixes:
https://code.google.com/p/thread-sanitizer/issues/detail?id=64
"Make it possible to suppress deadlock reports by any stack (not just first)"

llvm-svn: 209757
2014-05-28 18:03:32 +00:00
Kostya Serebryany 3df5d87da4 [sanitizer] print threads in deadlock report
llvm-svn: 204461
2014-03-21 13:00:18 +00:00
Dmitry Vyukov c9e12aa323 tsan: deobfuscate global ctx variable
llvm-svn: 204327
2014-03-20 10:36:20 +00:00
Dmitry Vyukov 6e2557769c tsan: use stack depot for goroutine creation stacks (as C++ threads do)
llvm-svn: 204326
2014-03-20 10:19:02 +00:00
Dmitry Vyukov 6cfab724ec tsan: refactor deadlock detector
Introduce DDetector interface between the tool and the DD itself.
It will help to experiment with other DD implementation,
as well as reuse DD in other tools.

llvm-svn: 202485
2014-02-28 10:48:13 +00:00
Dmitry Vyukov 249cd9af9c tsan: fix compiler warning
error: address of array 'tctx->name' will always evaluate to 'true'

llvm-svn: 202008
2014-02-24 08:19:53 +00:00
Kostya Serebryany b51f8d4990 [tsan] when printing a mutex, also print its address. Properly print the deadlock report.
llvm-svn: 201675
2014-02-19 14:17:25 +00:00
Evgeniy Stepanov 769d46f373 [sanitizer] Use system unwinder in signal handlers on Android.
Because of the way Bionic sets up signal stack frames, libc unwinder is unable
to step through it, resulting in broken SEGV stack traces.

Luckily, libcorkscrew.so on Android implements an unwinder that can start with
a signal context, thus sidestepping the issue.

llvm-svn: 201151
2014-02-11 13:38:57 +00:00
Dmitry Vyukov ce3721057d tsan: remove in_rtl counter
This is intended to address the following problem.
Episodically we see CHECK-failures when recursive interceptors call back into user code. Effectively we are not "in_rtl" at this point, but it's very complicated and fragile to properly maintain in_rtl property. Instead get rid of it. It was used mostly for sanity CHECKs, which basically never uncover real problems.
Instead introduce ignore_interceptors flag, which is used in very few narrow places to disable recursive interceptors (e.g. during runtime initialization).

llvm-svn: 197979
2013-12-24 12:55:56 +00:00
Dmitry Vyukov 3238e1c913 tsan: better diagnostics if thread finishes with ignores enabled
print thread creation stack
and stacks where ignores were enabled.

llvm-svn: 195836
2013-11-27 11:30:28 +00:00
Alexey Samsonov b3d939902a [Sanitizer] Make StackTrace::Unwind the only public way to unwind a stack trace.
llvm-svn: 194196
2013-11-07 07:28:33 +00:00
Dmitry Vyukov 464ebbd67b tsan: move shadow stack from thread descriptors to fixed addresses
This allows to increase max shadow stack size to 64K,
and reliably catch shadow stack overflows instead of silently
corrupting memory.

llvm-svn: 192797
2013-10-16 15:35:12 +00:00
Dmitry Vyukov 97f0eae0a5 tsan/msan: add halt_on_error flag
If halt_on_error==true, program terminates after reporting first error.

llvm-svn: 188279
2013-08-13 15:33:00 +00:00
Dmitry Vyukov 5cf581a8d4 tsan: consistently use return pc as top frame pc
always substract 1 from the top pc
this allows to get correct stacks with -O2

llvm-svn: 184112
2013-06-17 19:57:03 +00:00
Alexey Samsonov 0d7012debb [TSan] use InternalMmapVector to store fired suppressions
llvm-svn: 183974
2013-06-14 11:18:58 +00:00
Dmitry Vyukov a8570d38fe tsan: add -Wno-maybe-uninitialized to Go build script
this is how the rest of the codebase is built

llvm-svn: 183738
2013-06-11 11:44:43 +00:00
Dmitry Vyukov 315bb0e687 tsan: allows to suppress races on global variables
llvm-svn: 183672
2013-06-10 15:38:44 +00:00
Dmitry Vyukov ddb0294dd8 tsan: fix old gcc warnings
llvm-svn: 183645
2013-06-10 10:30:19 +00:00