llvm dev - Sep 2014 - [LLVMdev] Machine Code for different architectures

How does LLVM generate machine code for different architectures?
For example, the machine code for x86 and amd will vary.

How does LLVM convert its IR to machine code for different
architectures.Can you please explain the approach? Is it just write two
different programs for two different architectures and pass a flag to the
compiler based on which machine code you want to generate?

Thanks a lot for your explanations.

Thanks
Prakash
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http://llvm.org/docs/WritingAnLLVMBackend.html


On Tue, Sep 9, 2014 at 6:09 PM, Prakash Premkumar <prakash.prax at
gmail.com>
wrote:
> How does LLVM generate machine code for different architectures?
> For example, the machine code for x86 and amd will vary.
>
> How does LLVM convert its IR to machine code for different
> architectures.Can you please explain the approach? Is it just write two
> different programs for two different architectures and pass a flag to the
> compiler based on which machine code you want to generate?
>
> Thanks a lot for your explanations.
>
> Thanks
> Prakash
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
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Hi,

We have some DSP architectures (kalimba) which have 24-bits as their
"minimum addressable unit". So this means that the sizeof a char (and
an int and a short for that matter) is 24-bits.

I quickly read the posted link WritingAnLLVMBackend.html but did not
see an obvious answer to the following question:

Is it possible to write a backend that faithfully represents these
architectures or is sizeof_byte==8 bits baked into to llvm?

Does anyone have any views on the above?

thanks
Matthew Gardiner 


On Tue, 9 Sep 2014 18:21:01 +1200
Bruce Hoult <bruce at hoult.org> wrote:
> http://llvm.org/docs/WritingAnLLVMBackend.html
> 
> 
> On Tue, Sep 9, 2014 at 6:09 PM, Prakash Premkumar
> <prakash.prax at gmail.com> wrote:
> 
> > How does LLVM generate machine code for different architectures?
> > For example, the machine code for x86 and amd will vary.
> >
> > How does LLVM convert its IR to machine code for different
> > architectures.Can you please explain the approach? Is it just write
> > two different programs for two different architectures and pass a
> > flag to the compiler based on which machine code you want to
> > generate?
> >
> > Thanks a lot for your explanations.
> >
> > Thanks
> > Prakash
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
> >
> 
> 
>  To report this email as spam click
> https://www.mailcontrol.com/sr/MZbqvYs5QwJvpeaetUwhCQ== .


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