Cppless

Cppless is a single-source programming model for high-performance serverless. It enables you to write applications that offload work to serverless services, without the need to write the glue code needed to connect them.

The architecture of the compiler, including benchmark evaluation, details can be found in the thesis Cppless: A single-source programming model for high-performance serverless.

When using Cppless, please cite our ACM TACO paper (to appear). An extended version of our paper is available on arXiv.

@misc{cppless2025,
  title={Cppless: Single-Source and High-Performance Serverless Programming in C++}, 
  author={Marcin Copik and Lukas Möller and Alexandru Calotoiu and Torsten Hoefler},
  year={2025},
  eprint={2401.10834},
  archivePrefix={arXiv},
  primaryClass={cs.DC},
  url={https://arxiv.org/abs/2401.10834}, 
}

Building and installing

Building applications that use cppless requires using a custom fork of the clang compiler. The modified version of the llvm-project is included as a submodule in the repository, it can be built by following these steps:

• fetch the submodule
  • git submodule update --init --recursive (this will fetch only the latest revision, but will sped up the download)
  • Shallow clones cannot be used for contributing, you'll need to unshallow the clone in order to be able to commit changes to the submodule.
• run mkdir build && cd build in the root of the repository (llvm-project doesn't support in-tree builds)
• run cmake -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release -G "Unix Makefiles" ../llvm
  • This will build the modified clang compiler in a release configuration
• run make clang (or make clang -j <concurrency> if you want multiple tasks to run in parallel)
• this should produce a clang (and clang++) executable in the build/bin directory

The cmake configuration of this project will automatically use the clang executable from the build/bin directory, if you want to use cppless in your own project you'll have to instruct your build tool to use that version of clang accordingly

See the BUILDING document.

ARM Cross-compilation

To deploy ARM functions from an x86 system, check the documentation on setting up sysroot and toolchain in cmake/toolchains/aarch64.

Compatibility issues with stdlibc++

The Clang's verison, on which Cppless is based, should work with the gcc-based libstdc++ toolchain until version 11. If your OS has a new version, you need tell CMake to use a different toolchain to avoid potential incompatibilities.

Easiest way to do this:

mkdir -p toolchain/lib/gcc/x86_64-linux-gnu
cd toolchain/lib/gcc/x86_64-linux-gnu
ln -sfn /usr/lib/gcc/x86_64-linux-gnu/11 .

And in CMakeLists.txt add the following line:

set(CMAKE_CXX_FLAGS "--gcc-toolchain=/absolute/path/to/toolchain_root ${CMAKE_CXX_FLAGS}")

Benchmarks

Implementations:

• Fib
• Floorplan
• Knapsack
• NQueens
• Raycasting

Contributing

See the CONTRIBUTING document.