[llvm-dev] Critical XRay fixes for Arm32

[Serge Rogatch via llvm-dev]

There were no LLVM tests for presence of XRay instrumentation map in the
emitted assembly. You can see that https://reviews.llvm.org/D28624 adds
this check to the tests.
The tests in compiler-rt had been accidentally disabled.
https://reviews.llvm.org/D28623 enables them in
compiler-rt/test/xray/lit.cfg .

On 26 January 2017 at 22:37, Hans Wennborg <hans at chromium.org> wrote:

> 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
> >> >>
> >> >>
> >> >
> >
> >
>
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