DACPP

DACPP is a source-to-source translation project built on top of LLVM/Clang. It translates DACPP C++ source files into C++/SYCL code, with separate paths for single-node translation and MPI-enabled translation.

The main translator lives in:

clang/tools/translator

The repository is based on the LLVM monorepo layout. Most upstream LLVM components are kept in place because the translator is built as a Clang tool.

Features

• Translates DACPP source files to SYCL buffer-mode C++.
• Uses a single-node translator path for normal non-MPI translation.
• Uses an MPI-capable translator path when --mpi is requested.
• Provides wrapper scripts for translation, compilation, and one-step translate-and-build workflows.
• Supports building generated SYCL code with AdaptiveCpp, Intel oneAPI icpx, or an MPI C++ wrapper such as mpicxx.

Dependencies

Build Dependencies

To build the translator from source, install:

• CMake 3.20 or newer.
• Ninja, or another CMake-supported build tool.
• A C++17-capable host compiler.
• Python 3, required by the LLVM/Clang build system.
• Git.

On macOS, install Xcode Command Line Tools:

xcode-select --install

Runtime And Compilation Dependencies

To compile translated C++/SYCL output, install at least one SYCL compiler:

• AdaptiveCpp, configured with ACPP_ROOT or ADAPTIVECPP_ROOT.
• Intel oneAPI DPC++/C++ Compiler, available as icpx.
• An MPI C++ wrapper such as mpicxx when compiling MPI output.

For MPI translation and execution, install an MPI implementation such as OpenMPI, MPICH, or Intel MPI. On macOS with Homebrew, open-mpi and libomp are detected automatically when present.

Build

Configure the LLVM/Clang build from the repository root:

cmake -S llvm -B build -G Ninja \
  -DLLVM_ENABLE_PROJECTS="clang" \
  -DLLVM_TARGETS_TO_BUILD="host" \
  -DCMAKE_BUILD_TYPE=Release

Then build the DACPP translator:

cmake --build build --target translator -j8

This builds both executables:

build/bin/translator/translator
build/bin/translator/translator_single

translator_single must stay in the same directory as translator, because the main executable dispatches to it for non-MPI translation.

If your build directory is not build, set DACPP_TRANSLATOR before using the wrapper scripts:

export DACPP_TRANSLATOR=/path/to/build/bin/translator/translator

Environment

The public scripts are in clang/tools/translator:

clang/tools/translator/setenv.sh
clang/tools/translator/dacpp.sh

For interactive use, source the environment:

source clang/tools/translator/setenv.sh

dacpp.sh sources setenv.sh automatically, so sourcing is optional when using the wrapper directly.

Common environment variables:

Variable	Purpose
DACPP_TRANSLATOR	Path to the built translator executable.
DACPP_SYCL_COMPILER	Build backend: auto, adaptivecpp, icpx, or mpicxx. Default is auto.
ACPP_ROOT / ADAPTIVECPP_ROOT	AdaptiveCpp installation prefix.
ONEAPI_SETVARS	Full path to oneAPI setvars.sh.
ONEAPI_ROOT / INTEL_ONEAPI_ROOT	oneAPI installation prefix.
ICPX	Explicit path to icpx.
MPICXX	Explicit path to mpicxx.
DACPP_TMP_ROOT	Default directory for compiled binaries. Defaults to ${TMPDIR:-/tmp}.

In auto mode, the compiler backend is selected in this order:

1. AdaptiveCpp.
2. oneAPI icpx.
3. mpicxx.

Translate

Translate a non-MPI DACPP source file:

clang/tools/translator/dacpp.sh translate /path/to/file.dac.cpp --mode=buffer

Translate with MPI enabled:

clang/tools/translator/dacpp.sh translate /path/to/file.mpi.dac.cpp --mode=buffer --mpi

Pass compiler include paths and definitions after --:

clang/tools/translator/dacpp.sh translate /path/to/file.dac.cpp --mode=buffer -- \
  -I/path/to/include -DMY_DEFINE=1

Translator options, including --mpi, must appear before --.

Generated source files are written next to the input source file:

Input	Generated output
/path/to/file.dac.cpp	/path/to/file.dac_sycl_buffer.cpp
/path/to/file.mpi.dac.cpp	/path/to/file.mpi.dac_sycl_buffer.cpp

The translator does not currently provide a separate output-source path option. To place generated source in another directory, put the input source there before translation or move the generated file afterward.

Compile Translated Code

Compile generated code with the automatically detected backend:

clang/tools/translator/dacpp.sh build /path/to/file.dac_sycl_buffer.cpp /tmp/file_app

Compile with AdaptiveCpp:

ADAPTIVECPP_ROOT=/path/to/adaptivecpp \
DACPP_SYCL_COMPILER=adaptivecpp \
  clang/tools/translator/dacpp.sh build /path/to/file.dac_sycl_buffer.cpp /tmp/file_app

Compile with oneAPI icpx:

ONEAPI_ROOT=/path/to/oneapi \
DACPP_SYCL_COMPILER=icpx \
  clang/tools/translator/dacpp.sh build /path/to/file.dac_sycl_buffer.cpp /tmp/file_app

Compile MPI output with mpicxx:

DACPP_SYCL_COMPILER=mpicxx \
  clang/tools/translator/dacpp.sh build /path/to/file.mpi.dac_sycl_buffer.cpp /tmp/file_mpi_app

If the output binary path is omitted, the wrapper writes it to:

$DACPP_TMP_ROOT/<generated-file-basename-without-.cpp>

Translate And Build

For a one-step workflow:

clang/tools/translator/dacpp.sh translate-build /path/to/file.dac.cpp /tmp/file_app

For MPI:

DACPP_SYCL_COMPILER=mpicxx \
  clang/tools/translator/dacpp.sh translate-build /path/to/file.mpi.dac.cpp /tmp/file_mpi_app --mpi

Run MPI binaries with your MPI launcher:

mpirun -np 4 /tmp/file_mpi_app

More Documentation

See the translator-specific README for detailed script behavior and command reference:

clang/tools/translator/README.md

Upstream LLVM documentation is still present in component subdirectories because DACPP is built on the LLVM/Clang source tree.

License

This repository follows the LLVM project license. See LICENSE.TXT.