An Approximate Compiler

This is the documentation for ACCEPT, an approximate compiler for C and C++ programs based on Clang. Think of it as your assistant in breaking your program in small ways to trade off correctness for performance.

This is also the home for ACCEPT’s benchmark suite of approximate C/C++ applications.

Please direct comments or questions to Adrian Sampson or to a GitHub issue.

Building

Here’s how to build the ACCEPT toolchain in four easy steps.

Clone

Clone the repository to your Unix-like system. Use the submodules flag to grab the project’s dependencies:

$ git clone --recurse-submodules https://github.com/uwsampa/accept.git

CMake, Ninja, and virtualenv

There are three dependencies you need to install yourself before getting started. How you install them depends on your OS:

• CMake, which the easiest route to building LLVM.
• Ninja, a nice companion to CMake.
• virtualenv, a Python packaging tool. You can usually get this just by typing pip install virtualenv. For OS X with homebrew installed, you need to first intall python: brew install python.

(If you prefer not to use Ninja, you can fairly easily edit the relevant scripts to have CMake write Makefiles instead.)

make setup

Inside this directory (the repository containing this README.md file), type make setup. This will do several things:

• Download and extract the LLVM source.
• Build LLVM and our modified Clang frontend using CMake and Ninja. (This can take a long time.) The programs and libraries are installed into the build/built/ subdirectory.
• Build the ACCEPT-specific extensions to LLVM and Clang.
• Create a Python virtual environment and install the driver’s dependencies therein. Take a look inside the Makefile if you’re curious about how to run any of these steps individually.

You should now be able to use the bin/enerclang and bin/enerclang++ programs to compile EnerC programs. You can type make test to make sure everything’s working.

Using

The main entry point to the ACCEPT toolchain is the bin/accept script. For convenience, you can put this on your $PATH by running source activate.sh. Or you can add something like this to your shell profile (.profile or .bashrc file):

accept=~/path/to/your/git/checkout
export PATH=$accept/bin:$PATH

Follow the tutorial to learn how to use ACCEPT to optimize your favorite program. If you get stuck, check out the command-line interface reference.