Development Reference Guides

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Use a Third-Party Compiler as a Host Compiler for SYCL Code

This content describes the steps needed to use an external host compiler (G++) along with the
Intel® oneAPI
DPC++/C++
Compiler
.
In this example, you will use a host compiler to generate the host objects and perform the final link. The host compiler needs to know where to find the required headers and libraries. Follow the example instructions to build a SYCL program using a G++ Compiler (
g++
) for host code and an
Intel® oneAPI
DPC++/C++
Compiler
(
dpcpp
) for SYCL code.

For Linux

This example includes the following:
  • a.cpp
    : SYCL code
  • b.cpp
    : SYCL code
  • main.cpp
    : C++ code
  1. Follow the Get Started with the Intel® oneAPI Base Toolkit for Linux guide to set up the build environment:
    The build environment requires GCC version 5.1 or above to be installed and accessible.
    source /opt/intel/oneapi/setvars.sh
  2. Set up the headers and library locations:
    export LIBDIR=<Location of libsycl.so> export INCLUDEDIR=<Location of SYCL headers>
  3. Build the objects for your device:
    dpcpp -c a.cpp -fPIC -o a.o dpcpp -c b.cpp -fPIC -o b.o
  4. Create the integration header files (used by the host compiler):
    dpcpp -fsycl-device-only -Xclang -fsycl-int-header=a_host.h a.cpp dpcpp -fsycl-device-only -Xclang -fsycl-int-header=b_host.h b.cpp
  5. Create the host objects:
    g++ -std=c++17 -c a.cpp -o a_host.o -include a_host.h -fPIC -I$INCLUDEDIR g++ -std=c++17 -c b.cpp -o b_host.o -include b_host.h -fPIC -I$INCLUDEDIR
  6. Compile other C++ code (or non-SYCL code) using G++:
    g++ -std=c++17 main.cpp -c -fPIC -I$INCLUDEDIR
  7. Create a device object:
    dpcpp -fPIC -fsycl -fsycl-link a.o b.o -o device.o
  8. Create an archive
    libuser.a
    that contains the necessary host and device objects:
    This step is optional.
    ar -rcs libuser.a a_host.o b_host.o device.o
  9. Perform the final link to create a
    final.exe
    executable:
    g++ main.o a_host.o b_host.o device.o -L$LIBDIR -lOpenCL -lsycl -o finalexe.exe
  10. Build the
    final.exe
    with an archive:
    This step is optional.
    g++ main.o -Wl,--whole-archive libuser.a -Wl,--no-whole-archive -L$LIBDIR -lOpenCL -lsycl -o finalexe.exe

For Windows

Windows is not supported in this release.

Options

The compiler has two options that let you use an external compiler to perform host side compilation. The options are:
  • fsycl-host-compiler
    : Tells the compiler to use the specified compiler for host compilation of the performed offloading compilation.
  • fsycl-host-compiler-options
    : Passes options to the compiler specified by the option
    fsycl-host-compiler
    .

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.