OpenMP support for LLVM/Clang compiler
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OpenMP support for LLVM/Clang compiler


Clomp is based on LLVM version 3.2 source. In order to work Clomp needs a patch to be applyed to the Clang source, therefore it is not compatible with later versions of LLVM.

In order to install Clomp the following libraries are needed:

Install patched LLVM-3.2

In order to install the required patched version of LLVM a script is provided in the script folder called

In order for the script to find patched, it needs to be executed from the script directory.

cd script/
PREFIX=/my/llvm/installation/path sh 

The script will download and install LLVM in the given PREFIX path.

Create Project Makefile

Clomp is based on cmake. In order to build the makefile for the entire project run the following command from the root folder:

LLVM_HOME=/my/llvm/installation/path GTEST_ROOT=/gtest/build/path cmake .

Make sure that the LLVM_HOME enviroment variable points to the previously installed patched version of LLVM and that the C/C++ compiler seen by cmake is a c++0x capable compiler. If the compiler is installed in a non-standard location then provide the correct path to the cmake using the CC and CXX environment variables.


If the cmake run through without errors, then you are all set to compiler Clomp. Just run


and cross your fingers. Make file should produce two executables, one test case called ut_pragma_matcher and a second executable called clomp.

These are both programs to check basic functionalities of Clomp. Expecially the clomp executable can be used to list (on standard output) the list of OpenMP pragmas being recongnized from an input program. The program will print the location at which the pragmas are recognized and to which statements/declaration they are being applied.

./clomp-driver my_omp_test.c

Have fun and please contributed!


Clomp is released under the University of Illinois/NCSA Open Source License

What is missing?

Clomp takes care of parsing and attaching OpenMP pragmas to Clang's AST nodes. Clomp is currently uded in the Insieme compiler ( which maps OpenMP concepts into calls to a runtime designed for heterogenous systems. I was able to open the source of the OpenMP parser but not the runtime, furthermore I expected people to be more interested on having a runtime based on LLVM therefore I hope with this project to open the street to who-ever wants to provide OpenMP capabilities to LLVM. Drop me a line if you are interested in using Clomp.