[llvm-dev] Debugging JIT'ed code with ORC JIT?

[Lang Hames via llvm-dev]

HI Yichao,

RTDyldObjectLinkingLayer has a NotifyObjectLoaded hook that you can use to
call NotifyObjectEmitted on your GDBRegistrationListener.

If code is going to be unloaded we would have to add an extra hook to call
NotifyFreeingObject -- that seems totally reasonable to add.

-- Lang.


On Wed, Oct 11, 2017 at 10:44 AM, Yichao Yu <yyc1992 at gmail.com> wrote:

> > What debugging support MCJIT has is provided by the RuntimeDyld utility,
> > which ORC shares. I would expect anything in that document to apply to
> ORC
> > as well, though I haven't tested it personally.
>
> I'm pretty sure that's not the case, at least not with any simple
> orcjit tutorials I've seen.
>
> The GDB support is provided by `GDBJITRegistrationListener` which is
> registered to MCJIT directly in the constructor and AFAICT no where
> else. Also, since there doesn't seem to be a default (non-noop)
> implementation of `ExecutionEngine::RegisterJITEventListener` I
> believe you can't just call `RegisterJITEventListener` on non-MCJIT
> and expect it to work.
>
> So while I totally believe one can use
> `JITEventListener::createGDBRegistrationListener()` to hook the JIT
> with the the gdb registration function, it won't work without writing
> code to explicitly do that (in additional to actually writing code to
> interface with the event listener directly). OTOH though when using
> MCJIT, this is done by default and one don't need to write any code
> for it to work.
>
> >
> > For what it's worth, this is something I'm interested in and hope to make
> > some progress on in tree in the not too distant future.
> >
> > -- Lang.
> >
> > On Mon, Oct 9, 2017 at 12:27 PM, Jameson Nash via llvm-dev
> > <llvm-dev at lists.llvm.org> wrote:
> >>
> >> That is correct – there is no built-in support. You have to provide your
> >> own Registrar to the ObjectLinkingLayer to provide this sort of
> >> functionality. (For example JuliaLang does that at
> >> https://github.com/JuliaLang/julia/blob/1216e5f60cd2b23e29856b5227399a
> b0f3abef76/src/jitlayers.cpp#L437,
> >> in addition to registering the function pointer and object file info in
> >> several other places).
> >>
> >>
> >> On Sun, Oct 8, 2017 at 11:48 PM Connor Gray via llvm-dev
> >> <llvm-dev at lists.llvm.org> wrote:
> >>>
> >>> Hi,
> >>>
> >>> I’m wondering if it’s possible to debug code JIT’ed with the newer ORC
> >>> JIT. The LLVM documentation has a page at
> >>>
> >>>     llvm.org/docs/DebuggingJITedCode.html
> >>>
> >>> showing an example of using gdb to debug MCJIT’ed code, but has no
> >>> mention of ORC JIT.
> >>>
> >>> From searching around online I’ve gotten the impression that ORC JIT
> does
> >>> *not* support providing debugging information to attached debuggers,
> but no
> >>> definitive source. Is it the case that ORC JIT in fact does support
> >>> debugging, and if so, are there examples available; or is my initial
> >>> impression correct?
> >>>
> >>> Thanks,
> >>> Connor
> >>> _______________________________________________
> >>> LLVM Developers mailing list
> >>> llvm-dev at lists.llvm.org
> >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >>
> >>
> >> _______________________________________________
> >> LLVM Developers mailing list
> >> llvm-dev at lists.llvm.org
> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >>
> >
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > llvm-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >
>
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