llvm dev - Jul 2019 - JIT crashing when compiling source code with Clang and -mretpoline flag

Heyho both Mailinglists,

I'm not sure if I encountered a bug or if I'm doing something wrong. I
compiled a "Hello World"-function with Clang to LLVM-IR code, while
passing the "-mretpoline" flag.

I tried jitting and calling that function with the KaleidoscopeJIT code, but
when calling "lookup" for that function the application crashed.
I also tried that file in an old MCJIT implementation I had - there the
application crashed when calling the function (but it does find the address for
the function first).

If I recompile my code without the "-mretpoline" flag, everything
works fine again.
I compiled Clang and the LLVM files from the LLVM8 source files, I run them
under Windows7 64bit. Any ideas what might went wrong?

Kind greetings
Björn
Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr.
DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus
Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima. Junichi Tajika
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No experiences, opinions or thoughts on this? :c


From: cfe-dev <cfe-dev-bounces at lists.llvm.org> On Behalf Of Gaier,
Bjoern via cfe-dev
Sent: Freitag, 28. Juni 2019 07:52
To: llvm-dev <llvm-dev at lists.llvm.org>; cfe-dev at lists.llvm.org
Subject: [cfe-dev] JIT crashing when compiling source code with Clang and
-mretpoline flag

Heyho both Mailinglists,

I'm not sure if I encountered a bug or if I'm doing something wrong. I
compiled a "Hello World"-function with Clang to LLVM-IR code, while
passing the "-mretpoline" flag.

I tried jitting and calling that function with the KaleidoscopeJIT code, but
when calling "lookup" for that function the application crashed.
I also tried that file in an old MCJIT implementation I had - there the
application crashed when calling the function (but it does find the address for
the function first).

If I recompile my code without the "-mretpoline" flag, everything
works fine again.
I compiled Clang and the LLVM files from the LLVM8 source files, I run them
under Windows7 64bit. Any ideas what might went wrong?

Kind greetings
Björn

Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr.
DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus
Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima. Junichi Tajika
Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr.
DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus
Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima. Junichi Tajika
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You are also doing two things that are novel:
- using retpoline on JITed code (I think)
- doing it on Windows

So far as I know, you are the first person to do either of those things, so
no one is going to have any experience to share. I believe retpoline has
primarily been used in the kernel space, mainly for Linux, which uses ELF.

Finally, you haven't provided much info beyond "the application
crashed",
so even if someone was generous enough to try to diagnose the problem
remotely over email, there are no clues to analyze. I think you'll have to
debug things much further to get a useful response.

On Mon, Jul 15, 2019 at 1:48 AM Gaier, Bjoern via cfe-dev <
cfe-dev at lists.llvm.org> wrote:
> No experiences, opinions or thoughts on this? :c
>
>
>
>
>
> *From:* cfe-dev <cfe-dev-bounces at lists.llvm.org> *On Behalf Of
*Gaier,
> Bjoern via cfe-dev
> *Sent:* Freitag, 28. Juni 2019 07:52
> *To:* llvm-dev <llvm-dev at lists.llvm.org>; cfe-dev at
lists.llvm.org
> *Subject:* [cfe-dev] JIT crashing when compiling source code with Clang
> and -mretpoline flag
>
>
>
> Heyho both Mailinglists,
>
>
>
> I'm not sure if I encountered a bug or if I'm doing something
wrong. I
> compiled a "Hello World"-function with Clang to LLVM-IR code,
while passing
> the "-mretpoline" flag.
>
>
>
> I tried jitting and calling that function with the KaleidoscopeJIT code,
> but when calling "lookup" for that function the application
crashed.
>
> I also tried that file in an old MCJIT implementation I had - there the
> application crashed when calling the function (but it does find the address
> for the function first).
>
>
>
> If I recompile my code without the "-mretpoline" flag, everything
works
> fine again.
>
> I compiled Clang and the LLVM files from the LLVM8 source files, I run
> them under Windows7 64bit. Any ideas what might went wrong?
>
>
>
> Kind greetings
>
> Björn
>
>
>
> Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816,
> USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert
> Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima.
> Junichi Tajika
> Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816,
> USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert
> Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima.
> Junichi Tajika
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
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