[LLVMdev] asan coverage

[Bob Wilson]

I don’t know yet, but I will let you know as soon as I can.

On Nov 14, 2013, at 10:18 PM, Kostya Serebryany <kcc at google.com> wrote:

> On Fri, Nov 15, 2013 at 10:16 AM, Bob Wilson <bob.wilson at apple.com> wrote:
>> No, not that I am aware of.
> 
> So, if my commits did indeed trigger the failures it could be
> something like binary size change that caused different code alignment
> or some such
> and which triggered a latent memory bug somewhere else.
> 
> It's already late evening for you now. Will you have a chance to
> reapply changes today?
> 
> --kcc
> 
>> 
>> On Nov 14, 2013, at 10:15 PM, Kostya Serebryany <kcc at google.com> wrote:
>> 
>>> On Fri, Nov 15, 2013 at 10:14 AM, Bob Wilson <bob.wilson at apple.com> wrote:
>>>> The bit code file produced by the stage 1 compiler for one of the files in the clang driver is corrupt and causes the linker for stage 2 to crash.
>>> 
>>> Is AddressSanitizer involved in any of the stages of the LTO build?
>>> 
>>>> 
>>>> On Nov 14, 2013, at 10:13 PM, Kostya Serebryany <kcc at google.com> wrote:
>>>> 
>>>>> What are the symptoms?
>>>>> 
>>>>> On Fri, Nov 15, 2013 at 9:37 AM, Bob Wilson <bob.wilson at apple.com> wrote:
>>>>>> I’m waiting to see if this fixes the buildbots.  Unfortunately, because they were failing all day, there are a bunch of other regressions that have come up, and I’m still working through them.  It takes quite a while to run a bootstrapped LTO clang build, so it will take a while longer.
>>>>>> 
>>>>>> I don’t have any other useful information at this point, and I share your puzzlement about how your changes could possibly break the compiler.  My only hypothesis is some sort of memory corruption.
>>>>>> 
>>>>>> I will keep you posted.
>>>>>> 
>>>>>> On Nov 14, 2013, at 9:22 PM, Kostya Serebryany <kcc at google.com> wrote:
>>>>>> 
>>>>>>> Also, when are you planing to "reapply the changes or help debug"?
>>>>>>> 
>>>>>>> On Fri, Nov 15, 2013 at 9:15 AM, Kostya Serebryany <kcc at google.com> wrote:
>>>>>>>> On Fri, Nov 15, 2013 at 7:26 AM, Bob Wilson <bob.wilson at apple.com> wrote:
>>>>>>>>> Hi Kostya,
>>>>>>>>> 
>>>>>>>>> Thanks for the heads-up on this.  I haven’t had a chance to look into the
>>>>>>>>> details yet, but it looks like these patches may be breaking our
>>>>>>>>> bootstrapped LTO build.  Our buildbots have been failing all day, and we’re
>>>>>>>>> still trying to figure out the problem.  I’m going to speculatively revert
>>>>>>>>> those changes, since they were the only patches on the buildbot blame list.
>>>>>>>>> I will either reapply the changes or help debug the problem.
>>>>>>>> 
>>>>>>>> How could this possibly affect your LTO build?
>>>>>>>> The option is off by default.
>>>>>>>> Do you have any details, logs, etc?
>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> —Bob
>>>>>>>>> 
>>>>>>>>> On Nov 14, 2013, at 5:42 AM, Kostya Serebryany <kcc at google.com> wrote:
>>>>>>>>> 
>>>>>>>>> Bob, Justin,
>>>>>>>>> 
>>>>>>>>> I've just committed a poor man's coverage implementation that works with
>>>>>>>>> asan.
>>>>>>>>> http://llvm.org/viewvc/llvm-project?rev=194701&view=rev
>>>>>>>>> http://llvm.org/viewvc/llvm-project?rev=194702&view=rev
>>>>>>>>> It provides only function-level boolean coverage (i.e. no counters, just
>>>>>>>>> "visited or not"),
>>>>>>>>> but is very fast and very simple (no extra sections to the binary file, etc)
>>>>>>>>> I've tried it for Chrome's content_shell (huge and heavy binary) and the
>>>>>>>>> overhead
>>>>>>>>> is negligible at both run-time and shutdown-time.
>>>>>>>>> 
>>>>>>>>> We'll be evaluating this implementation and collecting usage stats.
>>>>>>>>> Maybe we want to implement something simple like this in the Clang coverage.
>>>>>>>>> 
>>>>>>>>> --kcc
>>>>>>>>> 
>>>>>>>>> 
>>>>>> 
>>>> 
>>