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Introduction#

Ubuntu 20.04 is the officially supported platform for p4c. There's also unofficial support for macOS 11. Other platforms are untested; you can try to use them, but YMMV.

A C++17 compiler. GCC 9.1 or later or Clang 6.0 or later is required.
git for version control
CMake 3.16.3 or higher
Boehm-Weiser garbage-collector C++ library
GNU Bison and Flex for the parser and lexical analyzer generators.
Google Protocol Buffers v3.25.3 or higher for control plane API generation
C++ boost library
Python 3 for scripting and running tests
Optional: Documentation generation (enabled when configuring with --enable-doxygen-doc) requires Doxygen (1.8.10 or higher) and Graphviz (2.38.0 or higher).

Backends may have additional dependencies. The dependencies for the backends included with p4c are documented here:

BMv2
eBPF
graphs

Ubuntu dependencies#

Most dependencies can be installed using apt-get install:

Bash Shell#

sudo apt-get install cmake g++ git automake libtool libgc-dev bison flex \

libfl-dev libboost-dev libboost-iostreams-dev \

libboost-graph-dev llvm pkg-config python3 python3-pip \

tcpdump

pip3 install --user -r requirements.txt

For documentation building: sudo apt-get install -y doxygen graphviz texlive-full

p4c also depends on Google Protocol Buffers (Protobuf). p4c requires version 3.0 or higher, so the packaged version provided in Ubuntu 20.04 should work. However, P4C typically installs its own version of Protobuf using CMake's FetchContent module (at the moment, 3.25.3). If you are experiencing issues with the Protobuf version shipped with your OS distribution, we recommend that to install Protobuf 3.25.3 from source. You can find instructions here. After cloning Protobuf and before you build, check-out version 3.25.3:

git checkout v3.25.3

Please note that while all Protobuf versions newer than 3.0 should work for p4c itself, you may run into trouble with some extensions and other p4lang projects unless you install version 3.25.3.

p4c also depends on Google Abseil library. This library is also a pre-requisite for Protobuf of any version newer than 3.21. Therefore the use of Protobuf of suitable version automatically fulfils Abseil dependency. P4C typically installs its own version of Abseil using CMake's FetchContent module (Abseil LTS 20240116.1 at the moment).

CMake#

p4c requires a CMake version of at least 3.16.3 or higher. On older systems, a newer version of CMake can be installed using pip3 install --user cmake==3.16.3. We have a CI test on Ubuntu 18.04 that uses this option, but there is no guarantee that this will lead to a successful build.

Fedora dependencies#

Bash Shell#

sudo dnf install -y cmake g++ git automake libtool gc-devel bison flex \

libfl-devel gmp-devel boost-devel boost-iostreams boost-graph llvm pkg-config \

python3 python3-pip tcpdump

sudo pip3 install -r requirements.txt

For documentation building:

sudo dnf install -y doxygen graphviz texlive-scheme-full

You can also look at the dependencies installation script for a fresh Fedora instance.

macOS dependencies#

Installing on macOS:

Enable XCode's command-line tools:
```
xcode-select --install
```

Install Homebrew:

/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
```
or with MacPorts
```
sudo port install autoconf automake coreutils libtool boehmgc boost bison pkg-config
```
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
```
Optional documentation building tools:
```
brew install doxygen graphviz
```
Homebrew offers a protobuf formula. It installs version 3.2, which should work for p4c itself but may cause problems with some extensions. It's preferable to use the version of Protobuf which is supplied with CMake's fetchcontent (3.25.3).

The protobuf formula requires the following CMake variables to be set, otherwise CMake does not find the libraries or fails in linking. It is likely that manually installed Protobuf will require similar treatment.

Terminal#

  PB_PREFIX="$(brew --prefix --installed protobuf)"
  ./bootstrap.sh \

    -DProtobuf_INCLUDE_DIR="${PB_PREFIX}/include/" \

    -DProtobuf_LIBRARY="${PB_PREFIX}/lib/libprotobuf.dylib" \

    -DENABLE_PROTOBUF_STATIC=OFF

Garbage collector#

P4c relies on BDW garbage collector to manage its memory. By default, the p4c executables are linked with the garbage collector library. When the GC causes problems, this can be disabled by setting ENABLE_GC cmake option to OFF. However, this will dramatically increase the memory usage by the compiler, and may become impractical for compiling large programs. Do not disable the GC, unless you really have to. We have noticed that this may be a problem on MacOS.

Crash dumps#

P4c will use libbacktrace to produce readable crash dumps if it is available. This is an optional dependency; if it is not available everything should build just fine, but crash dumps will not be very readable.