[compiler-rt] r269917 - [sanitizer] Fix a crash when demangling Swift symbols, take 3

[Kostya Serebryany via llvm-commits]

On Thu, May 19, 2016 at 4:02 AM, Kuba Brecka <jbrecka at apple.com> wrote:

>
> On 18 May 2016, at 20:00, Kostya Serebryany <kcc at google.com> wrote:
>
>
>
> On Wed, May 18, 2016 at 6:00 AM, Kuba Brecka via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: kuba.brecka
>> Date: Wed May 18 08:00:20 2016
>> New Revision: 269917
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=269917&view=rev
>> Log:
>> [sanitizer] Fix a crash when demangling Swift symbols, take 3
>>
>> The previous patch (r269291) was reverted (commented out) because the
>> patch caused leaks that
>> were detected by LSan and they broke some lit tests.  The actual reason
>> was that dlsym allocates
>> an error string buffer in TLS, and some LSan lit tests are intentionally
>> not scanning TLS for
>> root pointers.  This patch simply makes LSan ignore the allocation from
>> dlsym, because it's
>> not interesting anyway.
>>
>>
>> Modified:
>>     compiler-rt/trunk/lib/asan/asan_rtl.cc
>>     compiler-rt/trunk/lib/tsan/rtl/tsan_rtl.cc
>>
>> Modified: compiler-rt/trunk/lib/asan/asan_rtl.cc
>> URL:
>> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_rtl.cc?rev=269917&r1=269916&r2=269917&view=diff
>>
>> ==============================================================================
>> --- compiler-rt/trunk/lib/asan/asan_rtl.cc (original)
>> +++ compiler-rt/trunk/lib/asan/asan_rtl.cc Wed May 18 08:00:20 2016
>> @@ -553,8 +553,14 @@ static void AsanInitInternal() {
>>
>>    InitializeSuppressions();
>>
>> -  // TODO(kuba) Fix Me.
>> -  // Symbolizer::LateInitialize();
>> +  {
>> +#if CAN_SANITIZE_LEAKS
>>
>
> This adds one more #ifdef.
> Please, can we have fewer of those?
>
> if(CAN_SANITIZE_LEAKS) or similar would be much better!
>
>
> Again, I’d love to use regular ifs, but I thought doing so causes linker
> errors.  But, to my surprise, it seems that all my local builds work fine
> -- it seems that Clang just removes if(0) blocks even in debug builds.  Is
> that guaranteed?
>

I don't think this is really 100% guaranteed, but "if (0) code() " will
usually be deleted even at -O0.
If we see linker errors we should fix them by providing the stubs for
functions where they are missing.


> I committed r270038 to see how the other bots like this.
>

Thanks!


>
> Kuba
>
>
>
>
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