llvm dev - Oct 2015 - Can JIT be targeted to 32-bit in a 64-bit Wndows environment?

Hi

On 64-bit Windows the lack of proper stack unwinding support causes
crashes in JIT code generated by LLVM. I was wondering if it is
possible to ask LLVM to generate 32-bit code - and if that would work
within a 64-bit Windows application - i.e. the rest of the system will
be 64-bit only the generated code will be 32-bit. I was also wondering
if this would allow me to workaround the crashes due to stack
unwinding problems.

Thanks and Regards
Dibyendu

Hi Dibyendu,

I'm not familiar with Windows at all, but I assume you can't mix 64-bit
and
32-bit code in the one process.

Reid - Are we generating correct call frame information for windows yet (
https://llvm.org/PR24233) ? If so, I think Dibyendu would just have to
override registerEHFrames/deregisterEHFrames and have them call
RtlInstallFunctionTableCallback/RtlAddFunctionTable, right?

- Lang.

On Sun, Oct 25, 2015 at 5:30 AM, Dibyendu Majumdar via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi
>
> On 64-bit Windows the lack of proper stack unwinding support causes
> crashes in JIT code generated by LLVM. I was wondering if it is
> possible to ask LLVM to generate 32-bit code - and if that would work
> within a 64-bit Windows application - i.e. the rest of the system will
> be 64-bit only the generated code will be 32-bit. I was also wondering
> if this would allow me to workaround the crashes due to stack
> unwinding problems.
>
> Thanks and Regards
> Dibyendu
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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You actually can mix 32 and 64 bit code in the same Windows process, but
only with great effort. Fixing PR24233 is probably easier. :)

We know how to generate the info, but we still have to get it registered...

On Thu, Oct 29, 2015 at 2:19 PM, Lang Hames via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi Dibyendu,
>
> I'm not familiar with Windows at all, but I assume you can't mix
64-bit
> and 32-bit code in the one process.
>
> Reid - Are we generating correct call frame information for windows yet (
> https://llvm.org/PR24233) ? If so, I think Dibyendu would just have to
> override registerEHFrames/deregisterEHFrames and have them call
> RtlInstallFunctionTableCallback/RtlAddFunctionTable, right?
>
> - Lang.
>
> On Sun, Oct 25, 2015 at 5:30 AM, Dibyendu Majumdar via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Hi
>>
>> On 64-bit Windows the lack of proper stack unwinding support causes
>> crashes in JIT code generated by LLVM. I was wondering if it is
>> possible to ask LLVM to generate 32-bit code - and if that would work
>> within a 64-bit Windows application - i.e. the rest of the system will
>> be 64-bit only the generated code will be 32-bit. I was also wondering
>> if this would allow me to workaround the crashes due to stack
>> unwinding problems.
>>
>> Thanks and Regards
>> Dibyendu
>> _______________________________________________
>> 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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