[LLVMdev] LLVM ARM for shipped products?

Bob Wilson bob.wilson at apple.com
Fri Apr 17 14:07:01 PDT 2009

On Apr 17, 2009, at 1:39 PM, Robert Schuster wrote:
> I want to use llvm inside OpenJDK's runtime hotspot for which a  
> variant
> exists that uses llvm as a JIT compiler backend. Unfortunately the
> outstanding issues of the ARM backend in llvm make it crash often and
> not suitable for any real work.
> Some details here:
> http://rschuster.blogs.evolvis.org/2009/03/27/shark-bites-arm/

Hi Robert,

I read your blog entry.  The only specific problem you described was  
pr3877, which is that atomic intrinsics are not implemented for ARM.   
Versions of the ARM architecture prior to v6 do not support atomic  
operations very well, so depending on what kind of ARM processor  
you're using, you may need to solve this problem another way, e.g., by  
calling some external functions that can do things atomically.  It  
sounds like Xerxes already suggested that approach.  We should still  
fix pr3877, at least for ARM v6 and later, but I'm not sure about the  
priority of that.

Your comments above seem to indicate that you've run into many other  
problems with LLVM's ARM backend.  If any of those problems still  
exist in the latest version, could you be more specific about them?  I  
haven't experienced your problems with LLVM "crash[ing] often and not  
suitable for any real work".


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