llvm-3.7 release and OpenMP

Thu Sep 3 10:10:40 PDT 2015

I'll defer on rewriting the portfile for cmake.

I guess I like having libomp separate for now as it's much quicker to
update (build) it stand-alone while it's still getting frequent
updates. Note that (apparently) llvm is also packaging the OpenMP
runtime separately for now -- see the pre-built binaries section of
http://llvm.org/releases/download.html

I like your patch to teach clang where to look -- I'll add that when I
have a chance.

On Thu, Sep 3, 2015 at 11:21 AM, Jack Howarth
<howarth.at.macports at gmail.com> wrote:
>    You really will want to rewrite the llvm37 Portfile to use a cmake
> build. The openmp 3.7 can be built in-tree using cmake (with the
> sources placed at projects/openmp. Also the default for -fopenmp is
> still left as -fopenmp=libgomp in 3.7.0 but this can be changed
> with...
>
> --- cfe-3.7.0.src/CMakeLists.txt.orig 2015-09-02 12:21:32.000000000 -0400
> +++ cfe-3.7.0.src/CMakeLists.txt 2015-09-02 12:21:51.000000000 -0400
> @@ -182,7 +182,7 @@
>  set(DEFAULT_SYSROOT "" CACHE PATH
>    "Default <path> to all compiler invocations for --sysroot=<path>." )
>
> -set(CLANG_DEFAULT_OPENMP_RUNTIME "libgomp" CACHE STRING
> +set(CLANG_DEFAULT_OPENMP_RUNTIME "libomp" CACHE STRING
>    "Default OpenMP runtime used by -fopenmp.")
>
>  set(CLANG_VENDOR "" CACHE STRING
>
> In fink, we set the explicit location of the buried libomp.dylib with...
>
> --- cfe-3.7.0.src/lib/Driver/Tools.cpp.orig     2015-07-02
> 09:10:45.000000000 -0400
> +++ cfe-3.7.0.src/lib/Driver/Tools.cpp  2015-07-03 21:43:42.000000000 -0400
> @@ -6368,12 +6368,18 @@
>                     options::OPT_fno_openmp, false)) {
>      switch (getOpenMPRuntime(getToolChain(), Args)) {
>      case OMPRT_OMP:
> +      // Help clang find libomp.dylib
> +      CmdArgs.push_back("-L at FINK_PREFIX@/opt/llvm- at BRV@/lib");
>        CmdArgs.push_back("-lomp");
>        break;
>      case OMPRT_GOMP:
> +      // Help clang find libgomp.dylib
> +      CmdArgs.push_back("-L at FINK_PREFIX@/opt/llvm- at BRV@/lib");
>        CmdArgs.push_back("-lgomp");
>        break;
>      case OMPRT_IOMP5:
> +      // Help clang find libiomp5.dylib
> +      CmdArgs.push_back("-L at FINK_PREFIX@/opt/llvm- at BRV@/lib");
>        CmdArgs.push_back("-liomp5");
>        break;
>      case OMPRT_Unknown:
> @@ -8079,9 +8085,13 @@
>          // Also link the particular OpenMP runtimes.
>          switch (getOpenMPRuntime(ToolChain, Args)) {
>          case OMPRT_OMP:
> +         // Help clang find libomp.dylib
> +         CmdArgs.push_back("-L at FINK_PREFIX@/opt/llvm- at BRV@/lib");
>            CmdArgs.push_back("-lomp");
>            break;
>          case OMPRT_GOMP:
> +          // Help clang find libgomp.dylib
> +          CmdArgs.push_back("-L at FINK_PREFIX@/opt/llvm- at BRV@/lib");
>            CmdArgs.push_back("-lgomp");
>
>            // FIXME: Exclude this for platforms with libgomp that don't require
> @@ -8089,6 +8099,8 @@
>            CmdArgs.push_back("-lrt");
>            break;
>          case OMPRT_IOMP5:
> +         // Help clang find libiomp5.dylib
> +         CmdArgs.push_back("-L at FINK_PREFIX@/opt/llvm- at BRV@/lib");
>            CmdArgs.push_back("-liomp5");
>            break;
>          case OMPRT_Unknown:
>
> to produce -L/sw/opt/llvm-3.7/lib on the linkage. Lastly, to build the
> fat binary of libomp,
> you need to pass cmake the flag -DLIBOMP_OSX_ARCHITECTURES="x86_64;i386".
>                Jack
> ps Note that the perl-based Makefile build is no longer functional in
> 3.7.0 and is in the process of being completely removed for the 3.8.0
> release.
>
> On Wed, Sep 2, 2015 at 9:59 PM, Jeremy Huddleston Sequoia
> <jeremyhu at macports.org> wrote:
>> Looks good to me.  Could you go ahead and push this to svn and also do similar changes to the llvm-3.8 port for your openmp variant?
>>
>> Thanks,
>> Jeremy
>>
>>> On Sep 2, 2015, at 15:34, Eric A. Borisch <eborisch at macports.org> wrote:
>>>
>>> Would have done a ticket, but with trac down....
>>>
>>> Attached is a patch to update to the released llvm/clang-3.7 (this comments out the svn fetch code, removes the default +assertions, and adds checksums)
>>>
>>> As OpenMP is one of the much discussed items that llvm-3.7 brings to the table, I've added a +openmp variant to clang-3.7. This variants pulls in port:libomp and sets up clang such that "-fopenmp" will use it by default. This makes it much more likely for tools like autoconf to detect OpenMP support. (Without the variant, openmp support is still there, but it requires -fopenmp=libomp, which isn't in the set of standard "can we do OpenMP" flags.) If people are supportive of it, I would suggest making it a default variant.
>>>
>>> Note that -I/opt/local/include and -L/opt/local/lib (assuming standard MacPorts install location) are required with -fopenmp for things to work and not complain about missing omp.h or -lomp.
>>>
>>> If there is someone more familiar with clang/llvm building (of the tools themselves), it might be interesting to consider baking in those -I/-L flags (or move the libomp include/lib install directories so they only have omp.h and the libomp*.dylib files and using those) so -fopenmp would "just work." (Without the extra -I and -L)... Let me know if there is interest and I can rework the libomp port to support this.
>>>
>>> Thanks,
>>>   - Eric
>>> <llvm-3.7.patch>
>>
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