[Openmp-dev] Getting Architecture Patch

[C Bergström]

Ok looks good to me. If no objections from Carlo or others feel free to
push.

In the other thread I sent an updated patch which would apply over top this
change.

Thanks

On Thu, Dec 18, 2014 at 7:27 AM, Peyton, Jonathan L <
jonathan.l.peyton at intel.com> wrote:
>
>  New patch is attached.
>
>
>
> 1) No and no.  You can’t use #warn or #warning or the #pragma ways of
> doing a preprocessor warn/message/info because it isn’t standard (MSVC
> doesn’t have either #warn or #warning), #error is standard.  Also, you
> can’t rely on running a small program, and EVERYTHING I’ve seen emphasizes
> this point.  You can link but not actually run.  There is a specific
> reason, cross-compiling.  For example, if you relied on printf and are
> cross-compiling arm on an x86 host, then it won’t run on the x86 host
> system.
>
>
>
> Since you asked what others do, I had looked at what CMake does
> specifically when detecting the compiler:
>
> * Creates and links a small executable that has a main() function in it
> with a few global variables defined like
>
>      char cmake_compiler_name[] = “COMPILER_NAME=[gcc]”;
>
>      char cmake_compiler_version_major[] =
> “COMPILER_VERISON_MAJOR=[00000004]”
>
>      char cmake_compiler_version_minor[] =
> “COMPILER_VERISON_MINOR=[00000008]”
>
>      etc.
>
>      These variables are set through an extensive search through compiler
> predefined macros and some clever preprocessing macros/tricks.
>
> * Searches through the executable via regex to find something like
> “COMPILER_NAME=[gcc]” and extracts gcc, then 4, then 8 etc.
>
> * An aside: because not every compiler produces a.out as default
> executable and not every compiler has –o flag to redirect output, it
> searches every file that was produced in the temporary work space besides
> the temporary.c file.
>
> If you look at how LLVM does it, just look at GetHostTriple.cmake in
> llvm_root/cmake/modules/GetHostTriple.cmake.  It calls config.guess on
> non-Windows platforms J.
>
>
>
> 2) I personally don’t know about his one.  32e is embedded in lots of
> places including our internal tools and commercial product.  I can check
> with everybody else of course and see what they think, but you would have
> to wait till after the holiday season for anything to happen about it.
>
>
>
> 3) I did this in the new patch along with ppc64le
>
>
>
> -- Johnny
>
>
>
> *From:* C Bergström [mailto:cbergstrom at pathscale.com]
> *Sent:* Wednesday, December 17, 2014 1:24 PM
> *To:* Carlo Bertolli
> *Cc:* Peyton, Jonathan L; openmp-dev at dcs-maillist2.engr.illinois.edu
> *Subject:* Re: Getting Architecture Patch
>
>
>
> 3 nits
>
>
>
> 1) I think you can change it to #warn and avoid the compiler failure
> (please see what others are doing with similar approach and let me know).
> There's also possibility of actually linking and doing a printf which would
> avoid the whole regex mess.. Is there a strong reason for #error? (maybe
> faster?)
>
>
>
> 2) Would anyone @Intel strongly oppose a global rename of 32e to something
> which is more commonly used (x86_64, amd64 /* joking */ or x8664)
>
>
>
> 3) Can you include ARM64
>
>
>
> Thanks
>
>
>
> On Thu, Dec 18, 2014 at 1:53 AM, Carlo Bertolli <cbertol at us.ibm.com>
> wrote:
>
>  Hi Johnny
>
>
> Thanks for this patch. I will give it a try on our machines and let you
> know.
>
>
> Cheers
>
> -- Carlo
>
>
> [image: Inactive hide details for "Peyton, Jonathan L" ---12/17/2014
> 01:18:14 PM---Due to recent aarch64 and ppc64le port patches that]"Peyton,
> Jonathan L" ---12/17/2014 01:18:14 PM---Due to recent aarch64 and ppc64le
> port patches that have been sent, I have finished up this bit of c
>
> From: "Peyton, Jonathan L" <jonathan.l.peyton at intel.com>
> To: "openmp-dev at dcs-maillist2.engr.illinois.edu" <
> openmp-dev at dcs-maillist2.engr.illinois.edu>
> Cc: Carlo Bertolli/Watson/IBM at IBMUS, C Bergström <cbergstrom at pathscale.com
> >
> Date: 12/17/2014 01:18 PM
> Subject: Getting Architecture Patch
>  ------------------------------
>
>
>
>
> Due to recent aarch64 and ppc64le port patches that have been sent, I have
> finished up this bit of code for CMake which detects the architecture by
> probing the compiler.
>
> Carlo and C. Bergström can you two look at this patch and see if it
> adequately solves the detecting architecture problem for you both and add
> the proper macro into the GetArchitecture.cmake (this will make sense once
> you look at the patch)?  I would like this to be committed before either
> port so both ports can use this new patch.
>
> -- Johnny
>  [attachment "cmake_get_arch.patch" deleted by Carlo Bertolli/Watson/IBM]
>
>
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