This folder contains the C++ source code for the P4-16 compiler. This is a reference implementation of a compiler for the 2016 version of the P4 programming language, also called P4-16. The P4-16 draft spec is available at http://p4.org/wp-content/uploads/2016/12/P4_16-prerelease-Dec_16.html. For the P4 programming language see http://p4.org.

The code contains three sample compiler back-ends:

• p4c-bm2-ss: can be used to target the P4 simple_switch written using the BMv2 behavioral model https://github.com/p4lang/behavioral-model
• p4c-ebpf: can be used to generate C code which can be compiled to EBPF https://en.wikipedia.org/wiki/Berkeley_Packet_Filter and then loaded in the Linux kernel for packet filtering
• p4test: a source-to-source P4 translator which can be used for testing, learning compiler internals and debugging.

Some of these compilers can accept both P4-14 (i.e., P4 v1.0, v1.1) and P4-16 programs.

The code and documentation are hosted in the following git repository: https://github.com/p4lang/p4c

The code is currently alpha quality. Currently there is no way to install the compiler.

Dependences

We have tested the compiler on U*X systems (MacOS and Ubuntu). The following tools are required to build and run the compiler and tests:

• A C++11 compiler E.g., gcc 4.8 or later, or clang++

• git for version control

• GNU autotools for the build process

• Boehm-Weiser garbage-collector C++ library

• GNU Bison and Flex (parser and lexical analyzer generators)

• GNU multiple precision library GMP

• C++ boost library (minimally used)

• Python 2.7 for scripting (especially for running tests)

The compiler is modular, and it contains multiple back-ends. New ones can be added easily. Each back-end may have additional dependences. This repository contains the following two back-ends; please read the following documents for installing more dependences:

• BMv2
• eBPF

Ubuntu dependences

Most dependences can be installed using apt-get install:

sudo apt-get install g++ git automake libtool libgc-dev bison flex libgmp-dev libboost-dev python2.7 python-scapy python-ipaddr

macOS dependences

Installing on macOS:

• Enable XCode's command-line tools:

  xcode-select --install
  

• Install Homebrew:

  sudo /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
  

  Be sure to add /usr/local/bin/ to your $PATH.

• Install dependencies using Homebrew:

  brew install autoconf automake libtool bdw-gc boost bison pkg-config
  

  Install GMP built in C++11 mode:

  brew install gmp --c++11
  

  By default, Homebrew doesn't link programs into /usr/local/bin if they would conflict with a version provided by the base system. This includes Bison, since an older version ships with macOS. make check depends on the newer Bison we just installed from Homebrew (see #83), so you'll want to add it to your $PATH one way or another. One simple way to do that is to request that Homebrew link it into /usr/local/bin:

  brew link --force bison
  

Development tools

• We recommend installing a new version of gdb, because older gdb versions do not always handle C++11 correctly. See http://ftp.gnu.org/gnu/gdb.

• We recommend exuberant ctags for navigating source code in Emacs and vi. sudo apt-get install exuberant-ctags. The Makefile targets make ctags and make etags generate tags for vi and Emacs respectively. (Make sure that you are using the correct version of ctags; there are several competing programs with the same name in existence.)

• Steps for setting up Eclipse under Ubuntu Linux 14.04 can be found in Eclipse-readme.

Building

By default the build is performed in a separate folder build.

./bootstrap.sh
cd build
make -j4
make check -j4

We recommend using clang++ with no optimizations for speeding up compilation and simplifying debugging.

Additional documentation

More documentation is in docs/README.md