[llvm-dev] Critical XRay fixes for Arm32

[Hans Wennborg via llvm-dev]

I'm wondering why the lit tests didn't catch this as part of testing rc1 on ARM.

On Thu, Jan 26, 2017 at 11:25 AM, Serge Rogatch <serge.rogatch at gmail.com> wrote:
> XRay is tested automatically on build-bots with tests in LLVM and
> compiler-rt . Or are you asking for manual testing instructions?
> Of these 2 patches, the compiler-rt patch depends on LLVM patch because the
> tests compiler-rt\test\xray\TestCases\Linux would fail without the fix in
> LLVM. The compiler-rt patch also enables the tests which were occasionally
> disabled.
>
> The XRay feature is quite isolated, so side-effects are not expected. I can
> only see a risk that some commit I took for granted when making&testing the
> fixes, somehow didn't get to 4.0 branch.
>
>
> On 26 January 2017 at 21:44, Hans Wennborg <hans at chromium.org> wrote:
>>
>> How is XRay tested? IIRC, Renato didn't see any test failures on ARM?
>>
>> Merging sounds reasonbaly, I'd just like to understand what's the risk
>> for the branch.
>>
>> On Thu, Jan 26, 2017 at 10:29 AM, Serge Rogatch <serge.rogatch at gmail.com>
>> wrote:
>> > Hans, these changes reached trunk in https://reviews.llvm.org/rL292516
>> > and
>> > https://reviews.llvm.org/rL292517 . Could you look?
>> >
>> > On 26 January 2017 at 03:29, Serge Rogatch <serge.rogatch at gmail.com>
>> > wrote:
>> >>
>> >> Sorry, I initially included LLVM-Commits rather than LLVM-Dev. Fixed.
>> >>
>> >> On 26 January 2017 at 03:26, Serge Rogatch <serge.rogatch at gmail.com>
>> >> wrote:
>> >>>
>> >>> Hi Dean, Renato,
>> >>>
>> >>> AFAIK, unfortunately, these critical Arm32 XRay fixes are not yet in
>> >>> 4.0:
>> >>> https://reviews.llvm.org/D28624 , https://reviews.llvm.org/D28623 .
>> >>> The
>> >>> first repairs XRay instrumentation map emission. Without this map XRay
>> >>> doesn't work at all: the runtime doesn't see anything to instrument.
>> >>> The
>> >>> second fixes the CPU cache incoherency problem. Without this patch,
>> >>> XRay
>> >>> will intermittently fail to patch or unpatch some sleds (depending on
>> >>> whether their code is in CPU cache or not).
>> >>>
>> >>> Is there any chance we can get these patches to 4.0? This page
>> >>> http://llvm.org/docs/HowToReleaseLLVM.html#release-patch-rules says
>> >>> that
>> >>> "release manager, the official release testers or the code owners" may
>> >>> approve cherry-picking to release branch from trunk. AFAIK, you are
>> >>> code
>> >>> owners for XRay and ARM. I don't know who are the release manager or
>> >>> official release testers.
>> >>>
>> >>> Cheers,
>> >>> Serge
>> >>
>> >>
>> >
>
>