Conan Recipe and SYCL as a CMake Language for ComputeCpp

This repository contains a recipe for repackaging ComputeCpp as a conan package together with a set of CMake modules that allow the use SYCL without any usage of macros.

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WARNING: Both the Conan recipe and the CMake modules are highly experimental. They are likely to break as development of both ComputeCpp and the scripts themselves progress.

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Prerequisites

• CMake 3.7 or greater
• Conan

Both CMake and Conan are also available on pip:

pip install --user cmake conan

Creating a Conan package

The conan recipe won't download ComputeCpp by itself. You need to download it from the Codeplay website and place the tarball into the same directory as conanfile.py. After that, you can create your package as usual:

cd conan-computecpp
conan create . codeplay/testing

Using ComputeCpp with CMake

Note that the FindComputeCpp.cmake module from the SDK will still work with the conan package.

The recipe also installs an experimental set of CMake modules that integrate SYCL tightly into CMake such that enabling SYCL is as simple as find_package(ComputeCpp):

CMakeLists.txt

cmake_minimum_required(VERSION 3.7)
project(hello_sycl)

# This will enable SYCL as a CMake language and set compute++ to be its compiler
find_package(ComputeCpp REQUIRED)

# The device compiler will be automatically invoked on each .cpp file.
# Every target containing SYCL code will implicitly link against ComputeCpp
add_executable(app my_parallel_code.cpp)

conanfile.txt

[requires]
computecpp/0.8.0@codeplay/testing

[generators]
cmake_paths

Build process:

mkdir build
cd build
conan install ..
cmake .. -DCMAKE_TOOLCHAIN_FILE=conan_paths.cmake [-GNinja]
ninja

When invoking CMake, the configuration log should print out something similar to this:

-- The C compiler identification is GNU 8.1.0
-- The CXX compiler identification is GNU 8.1.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Current conanbuildinfo.cmake directory: /home/morris/Projects/hello_sycl/build
-- Conan: Compiler GCC>=5, checking major version 8.1
-- Conan: Checking correct version: 8.1
-- Conan: Using cmake global configuration
-- Conan: Adjusting language standard
-- Found SYCL: /home/morris/.conan/data/computecpp/0.8.0/codeplay/testing/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/bin/compute++ (found version "CE 0.8.0")
-- The SYCL compiler identification is ComputeCpp CE 0.8.0
-- Check for working SYCL compiler: /home/morris/.conan/data/computecpp/0.8.0/codeplay/testing/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/bin/compute++
-- Check for working SYCL compiler: /home/morris/.conan/data/computecpp/0.8.0/codeplay/testing/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/bin/compute++ -- works
-- Detecting SYCL compiler ABI info
-- Detecting SYCL compiler ABI info - done
-- Configuring done
-- Generating done
-- Build files have been written to: /home/morris/Projects/hello_sycl/build

Opting out of SYCL

To exclude just a couple of files, use set_source_files_properties:

add_executable(app my_parallel_code.cpp cpu_only.cpp more_cpu_only_code.cpp)
set_source_files_properties(cpu_only.cpp more_cpu_only_code.cpp PROPERTIES LANGUAGE CXX)

To make SYCL opt-in, you have to enable the CXX language after the find_package(ComputeCpp) call:

cmake_minimum_required(VERSION 3.4)
project(hello_sycl LANGUAGES C)

find_package(ComputeCpp REQUIRED)
enable_language(CXX)

# The host compiler will be invoked for each .cpp file unless overridden by set_source_files_properties
add_executable(app my_parallel_code.cpp cpu_only.cpp more_cpu_only_code.cpp)
set_source_files_properties(my_parallel_code.cpp PROPERTIES LANGUAGE SYCL)

Current Limitations

• This is completely untested on Windows
• Currently only the SYCL driver mode is supported. Using a separate compiler for the host code might be feasible
• The rpath won't be set correctly unless the LINKER_LANGUAGE of the target is forced to CXX
• CMAKE_CXX_STANDARD, CMAKE_SYCL_STANDARD and compile features are not supported. This will probably require an upstream change to CMake.
• TriSYCL is not supported yet

License

The build scripts are license under the Apache 2.0 license. Check the ComputeCpp end user agreement for the license of ComputeCpp itself.

The CMake modules are based on upstream CMake modules. Please see the files for their respective licences.