On Wed, Mar 3, 2021 at 2:35 PM Stefan Gränitz <stefan.graenitz at
gmail.com>
wrote:
> Yes, got it and I also wonder if there's a better low hanging solution.
>
> The underlying question that I wanted to point out was: Would the escape
> to Support be a one-time solution for JITSymbol or will we see more of the
> same soon. GDB JIT interface seems to be the next candidate, but OTOH
it's
> quite a special case again. I will have a look at OProfile and Perf
> implementations for RuntimeDyld to make a better estimation.
>
> I guess you'd prefer us to act on it soon now?
>
I'm not too pressed - Google's unblocked by lumping JITSymbol into
Support
(we can do this just in the build files without having to move the file
around), but the sooner these things are resolved the better to avoid other
things layering on top of them, etc.
> What time frame are you having in mind? Is next week acceptable? (I am
> more or less ooo for the rest of the week.)
>
Sure
>
> @Peter, @Nico: I've noticed your post-review comments. I will have a
look
> tonight (~10h from now).
>
> These should be fixed now. Thanks again for reporting your issues and
> sorry for the inconvenience.
>
> On 03/03/2021 19:40, David Blaikie wrote:
>
> To clarify, I'm not sure JITSymbol should be in llvmSupport, but that
it's
> the only place it can be right now that would be correct. Maybe there's
> some other layering changes (not necessarily introducing a new library, but
> possibly changing other dependency edges, etc) - but maybe there's
already
> some JIT Stuff in llvmSupport and that's where it should go. It's a
simple
> enough header/wouldn't come at a great cost to include it in Support.
>
> On Wed, Mar 3, 2021 at 1:51 AM Stefan Gränitz <stefan.graenitz at
gmail.com>
> wrote:
>
>> Hi David
>>
>> Thanks for the details. Yes, the layering issue is something we should
>> take care of soon. It also makes trouble for the modules build (see:
>> https://reviews.llvm.org/D95747).
>>
>> I think we should split up the JITSymbol.h and move JITTargetAddress
into
>> OrcShared. What remains would be the JITSymbol class. Moving this one
to
>> Support sounds like a nice solution to me.
>>
>> However, we have a similar situation with the GDB JIT interface
>> declarations. They should have their own header, yes, but where would
we
>> put it? Support too? Not sure about it. Having the definition only in
>> OrcTargetProcess would be acceptable IMHO. The only alternative seems
to be
>> an entirely new library (as discussed in the review
>> https://reviews.llvm.org/D97339).
>>
>> What do you think?
>>
>> @Peter, @Nico: I've noticed your post-review comments. I will have
a look
>> tonight (~10h from now).
>>
>> Best,
>> Stefan
>>
>> On 03/03/2021 04:57, David Blaikie wrote:
>>
>> Seems one of the latest Orc changes (
>>
https://github.com/llvm/llvm-project/commit/99a6d003edbe97fcb94854547276ffad3382ec1d
>> ) while not itself changing/breaking the layering in LLVM's own
build, it
>> has revealed some pre-existing problems with the layering that we'd
worked
>> around at Google in a way that isn't viable after this recent
change.
>>
>> One immediate/easily observed issue: lib/ExecutionEngine's
CMakeLists.txt
>> says it depends on OrcTargetProcess, but OrcTargetProcess includes
>> lib/ExecutionEngine/JITSymbol.h
>>
>> The only common dependency for all the uses of JITSymbol.h seems to be
>> llvm/Support (ie: without introducing new dependencies or new
libraries,
>> JITSymbol.h would need to be moved to llvm/Support to fix this
particular
>> dependency cycle/issue)
>>
>> We do have a bunch of other workarounds for Orc layering in the Google
>> internal build system too - so perhaps I can enumerate some/all of the
>> issues here, as it might be best to take a holistic approach to fixing
>> these issues.
>>
>> Let's see what I can document/figure out...
>>
>> ExecutionEngine/Orc -> ExecutionEngine
>> ExecutionEngine/Interpreter -> ExecutionEngine
>> ExecutionEngine/RuntimeDyld -> ExecutionEngine
>> ExecutionEngine/IntelJITEvents -> ExecutionEngine
>> ExecutionEngine/OProfileJIT -> ExecutionEngine
>> ExecutionEngine/PerfJITEvents -> ExecutionEngine
>> ExecutionEngine/MCJIT -> ExecutionEngine
>>
>> And there's actually no #includes in ExecutionEngine that reference
those
>> libraries, so that's pretty good.
>>
>> It is this CMakeLists.txt dependency from ExecutionEngine to
>> OrcTargetProcess. Which happens without a #include:
>>
>> $ grep -r "void __jit_debug_register_code" llvm/
>>
>> llvm/lib/ExecutionEngine/GDBRegistrationListener.cpp: extern
"C" *void
>> __jit_debug_register_code*();
>>
>>
llvm/lib/ExecutionEngine/Orc/TargetProcess/JITLoaderGDB.cpp:LLVM_ATTRIBUTE_NOINLINE
>> *void __jit_debug_register_code*() {
>>
>> Would be better if this wasn't declared arbitrarily (instead, if it
was
>> declared in a header and defined as usual, the circular dependence
would be
>> more clear, I think?) - but either way, the circular dependency needs
to be
>> fixed.
>>
>> - Dave
>>
>>
>>
>> -- https://flowcrypt.com/pub/stefan.graenitz at gmail.com
>>
>> -- https://flowcrypt.com/pub/stefan.graenitz at gmail.com
>
>
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