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Subject: Re: [OMPI devel] debugger changes
From: George Bosilca (bosilca_at_[hidden])
Date: 2011-11-08 18:29:16


On Nov 8, 2011, at 17:56 , Paul H. Hargrove wrote:

> In theory, might a sufficiently smart compiler and linker eliminate some MPIR_* variables after optimization?

Even if a compiler can optimize out symbols from an application, I doubt they are allowed to apply the same optimization on libraries. As our MPIR_ symbols are defined as externally visible in libopen-rte.so (and some in libmpi.so), so I guess we're safe.

However, this might be an issue when we compile statically … It is not an absolute proof, but I quickly checked with a static build and the MPIR_* symbols are still there with both gcc and icc.

> If that could potentially be true, then perhaps the volatile qualifier would prevent such a removal, which would break the existence check(s) by the debugger? Just a thought.

If we really want to have a clear answer to this, I guess we should ask a hard-core compiler guru about …

  george.

>
> -Paul
>
> On 11/8/2011 2:46 PM, George Bosilca wrote:
>> This value is not even read by the debugger. It only check for it's existence in the startup process, so I guess we're safe here as well.
>
> --
> Paul H. Hargrove PHHargrove_at_[hidden]
> Future Technologies Group
> HPC Research Department Tel: +1-510-495-2352
> Lawrence Berkeley National Laboratory Fax: +1-510-486-6900
>
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