[llvm-dev] Critical XRay fixes for Arm32

[Serge Rogatch via llvm-dev]

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
> >>
> >>
> >
>
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