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Clang UPC and OpenMP/Clang

The goal of this project is to allow interoperability of Clang UPC and OpenMP. For this purpose an OpenMP/Clang branch has been merged into the Clang UPC project.

Running the UPC code with OMP support requires Intel’s OpenMP Runtime Library.

Getting Clang UPC with OpenMP support

Follow these instructions to build Clang UPC with OpenMP.

  • Clone the following repositories
git clone git://github.com/Intrepid/llvm-upc.git llvm
git clone git://github.com/Intrepid/clang-upc.git llvm/tools/clang
  • Additionally, clone the Clang compiler runtime library
git clone https://github.com/clang-omp/compiler-rt_trunk llvm/projects/compiler-rt

  • Build the same way as building Clang UPC.

  • build and install Intel’s OpenMP Runtime Library.

UPC/OMP interoperability

The following restrictions apply when executing OMP code in UPC environment:

  • OMP worker threads are not allowed to execute UPC code. For example, code accessing shared scalars and arrays, UPC barriers, UPC locks, and UPC allocations is allowed on the OMP master thread only (UPC thread).

Configuration Options

There are no OpenMP specific options in Clang UPC. However, special check for UPC code inside the OMP code sections is added when compiler is built with -DLIBUPC_ENABLE_RUNTIME_OMP_CHECKS option enabled.

Compile Options

The following compile time option has been added:

  • -fopenmp

    Generate OpenMP specific code.

Also, as required by OpenMP/Clang, add the following to your environment as Clang UPC needs to fund omp.h, as well as OpenMP runtime library.

export PATH=/install/prefix/bin:$PATH
export C_INCLUDE_PATH=/install/prefix/include:OpenMP include path:$C_INCLUDE_PATH
export LIBRARY_PATH=/install/prefix/lib:OpenMP library path:$LIBRARY_PATH
export LD_LIBRARY_PATH=/install/prefix/lib:OpenMP library path:$LD_LIBRARY_PATH

Current Status

All the work done on this project is on a special clang-omp branch.

  • 05/25/2015 - clang-omp branch merged into the main development branch
  • 03/01/2015 - OpenMp/Clang branch merged into Clang UPC

References