[LLVMdev] Set up ExecutionEngine according to actual machine capabilities

[Yaron Keren]

That's odd. getHostCPUName uses cpuid to get the actual capabilities of the
CPU before selecting the name.
Does cpuid reports incorrect information in these virtual machines?

In any case you can further tune CPU capabilities with
EngineBuilder::setMAttrs.


2015-05-11 11:59 GMT+03:00 Mueller-Roemer, Johannes Sebastian <
Johannes.Sebastian.Mueller-Roemer at igd.fraunhofer.de>:

>  I am currently setting up my Module with
>
>
>
> module->setTargetTriple(llvm::sys::getProcessTriple()
>
> #ifdef _WIN32
>
>                                + "-elf"
>
> #endif
>
> );
>
>
>
> And my ExecutionEngine with
>
>
>
> llvm::EngineBuilder(std::move(module))
>
>                                                .setErrorStr(&err)
>
>
> .setMCPU(llvm::sys::getHostCPUName())
>
>                                                .create()
>
>
>
> This works fine on most machines, however on some virtualized machines
> this fails because the host CPU name implies AVX, however AVX is in fact
> disabled, leading to an illegal instruction when running JIT-compiled
> functions.
>
>
>
> Is there a better way to set up the executionengine so that such failure
> do not occur (but all available features are used)?
>
>
>
> --
>
> Johannes S. Mueller-Roemer, MSc
>
> Wiss. Mitarbeiter - Interactive Engineering Technologies (IET)
>
>
>
> Fraunhofer-Institut für Graphische Datenverarbeitung IGD
>
> Fraunhoferstr. 5  |  64283 Darmstadt  |  Germany
>
> Tel +49 6151 155-606  |  Fax +49 6151 155-139
>
> johannes.mueller-roemer at igd.fraunhofer.de  |  www.igd.fraunhofer.de
>
>
>
> _______________________________________________
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>
>
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