Intel® Cilk™ Plus is an open source project now. It is supported in GCC* 4.7 but still not merged into the released GCC* 4.7.0 version. We can build the 'cilkplus' branch of GCC* to make it support the Intel® Cilk™ Plus extensions. The steps are exact same with building GCC* upstream code, so this article is targeted for those who are not familiar with building GCC and want to use Cilk Plus with GCC.

(1) Preparation

OS: Ubuntu* 12.04 LTS beta2 64bit.

Install following packages before building GCC Cilk Plus:

sudo apt-get install binutils
sudo apt-get install build-essential
sudo apt-get install m4
sudo apt-get install autogen
sudo apt-get install bison

(2) Install gmp

1. download gmp (gmp-4.3.2.tar.bz2) from: ftp://gcc.gnu.org/pub/gcc/infrastructure/

2. compile and install gmp:

sudo mkdir -p /opt/gmp-4.3.2
tar -jxvf gmp-4.3.2.tar.bz2
cd gmp-4.3.2
./configure --prefix=/opt/gmp-4.3.2
make && make check && sudo make install

Notes: It is recommended to run 'make check'.

(3) Install mpfr

1. download mpfr (mpfr-2.4.2.tar.bz2) from same link as above.

2. compile and install mpfr:

sudo mkdir -p /opt/mpfr-2.4.2
tar -jxvf mpfr-2.4.2.tar.bz2
cd mpfr-2.4.2
./configure --prefix=/opt/mpfr-2.4.2 --with-gmp=/opt/gmp-4.3.2
make && make check && sudo make install

Notes: You must install gmp before installing 'mpfr' as 'mpfr' depends on 'gmp'.

(4) install mpc

1. download mpc (mpc-0.8.1.tar.gz) from same link as above.

2. compile and install mpc:

sudo mkdir -p /opt/mpc-0.8.1
tar -zxvf mpc-0.8.1.tar.gz
cd mpc-0.8.1
./configure --prefix=/opt/mpc-0.8.1 --with-gmp=/opt/gmp-4.3.2 --with-mpfr=/opt/mpfr-2.4.2
make && make check && sudo make install

Notes: 'mpc' depends on 'gmp' and 'mpfr'.

(5) build and install GCC with Cilk Plus

1. download the source code of 'cilkplus' branch. There are various ways to download it.

SVN:

The cilkplus-4_7-branch: http://gcc.gnu.org/svn/gcc/branches/cilkplus-4_7-branch/

The cilkplus branch: http://gcc.gnu.org/svn/gcc/branches/cilkplus/

GIT:

The GIT mirror: http://gcc.gnu.org/git/?p=gcc.git;a=shortlog;h=refs/heads/cilkplus

Here, I download the git mirror for cilkplus branch through browser directly. (The snapshot is 'gcc-0dfa790.tar.gz')

2. compile and install gcc cilkplus branch:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/gmp-4.3.2/lib:/opt/mpfr-2.4.2/lib:/opt/mpc-0.8.1/lib
export C_INCLUDE_PATH=/usr/include/x86_64-linux-gnu && export CPLUS_INCLUDE_PATH=$C_INCLUDE_PATH && export OBJC_INCLUDE_PATH=$C_INCLUDE_PATH
export LIBRARY_PATH=/usr/lib/x86_64-linux-gnu

tar -zxvf gcc-0dfa790.tar.gz
sudo mkdir -p /opt/gcc-4.7-cilkplus
mkdir gcc_cilkplu_build && cd gcc_cilkplu_build
../gcc-0dfa790/configure --prefix=/opt/gcc-4.7-cilkplus --with-gmp=/opt/gmp-4.3.2 --with-mpfr=/opt/mpfr-2.4.2 --with-mpc=/opt/mpc-0.8.1 --disable-multilib --enable-languages=c,c++
make -j8
sudo make install

Notes:

(1) It is suggested to run 'configure' in a standalone foler instead of running it in the source tree of gcc cilkplus.

(2) 'make -j8', this step will build the source code, it will take quite a long time, you may change the argument of '-j' according to your system.

(6) Create the 'gccvars.sh' script

This is optional, you may create a script to help to set the environment of the built gcc. Following is a reference for 'gccvars.sh':

# filename: gccvars.sh
# 'source gccvars.sh' to set the environment of gcc
export C_INCLUDE_PATH=/usr/include/x86_64-linux-gnu:$C_INCLUDE_PATH
export CPLUS_INCLUDE_PATH=$C_INCLUDE_PATH
export OBJC_INCLUDE_PATH=$C_INCLUDE_PATH
export LIBRARY_PATH=/usr/lib/x86_64-linux-gnu:$LIBRARY_PATH

export GCCDIR=/opt/gcc-4.7-cilkplus
export PATH=$GCCDIR/bin:$PATH
export LD_LIBRARY_PATH=$GCCDIR/lib:$GCCDIR/lib64:/opt/gmp-4.3.2/lib:/opt/mpfr-2.4.2/lib:/opt/mpc-0.8.1/lib:$LD_LIBRARY_PATH
export MANPATH=$GCCDIR/share/man:$MANPATH

Notes: GCCDIR is the installed path of the built gcc.

(7) Test Cilk Plus with GCC

To use cilk plus with gcc, you need to add '-lcilkrts' flag to the command line. See below test case for more details (it contains how to compile and the results):

// filename: test_cilkplus.cpp
// compile: g++ test_cilkplus.cpp -lcilkrts

#include <stdio.h>
#include <unistd.h>

#include <cilk/cilk.h>
#include <cilk/cilk_api.h>

void task(int i) {
    printf("task: %d, workder id: %d\n", i, __cilkrts_get_worker_number());
    sleep(1);
}

int main() {
    for(int i=0;i<10;i++)
	    cilk_spawn task(i);
    cilk_spawn task(-1);
    cilk_sync;
    return 0;
}

/* compile and result:
#g++ test_cilkplus.cpp -lcilkrts
#./a.out 
task: 0, workder id: 0
task: 1, workder id: 1
task: 2, workder id: 2
task: 3, workder id: 0
task: 4, workder id: 1
task: 5, workder id: 2
task: 6, workder id: 0
task: 7, workder id: 1
task: 8, workder id: 2
task: 9, workder id: 0
task: -1, workder id: 1
#
notes: you can use 'export CILK_NWORKERS=N' to set the max workders of cilk plus runtime.
*/

(8) Resources for the Cilk Plus Open Source Project