Installing p4c from source#

Clone the repository. It includes submodules, so be sure to use --recursive to pull them in:
```
git clone --recursive https://github.com/p4lang/p4c.git
```
If you forgot --recursive, you can update the submodules at any time using:
```
git submodule update --init --recursive
```
Install dependencies. You can find specific instructions for Ubuntu 20.04 here and for macOS 11 here. You can also look at the CI installation script.
Build. Building should also take place in a subdirectory named build.
```
mkdir build
cd build
cmake .. <optional arguments>
make -j4
make -j4 check
```
The cmake command takes the following optional arguments to further customize the build:
- -DCMAKE_BUILD_TYPE=RELEASE|DEBUG -- set CMAKE_BUILD_TYPE to RELEASE or DEBUG to build with optimizations or with debug symbols to run in gdb. Default is RELEASE.
- -DCMAKE_INSTALL_PREFIX=<path> -- set the directory where make install installs the compiler. Defaults to /usr/local.
- -DENABLE_BMV2=ON|OFF. Enable the bmv2 backend. Default ON.
- -DENABLE_EBPF=ON|OFF. Enable the ebpf backend. Default ON.
- -DENABLE_UBPF=ON|OFF. Enable the ubpf backend. Default ON.
- -DENABLE_DPDK=ON|OFF. Enable the DPDK backend. Default ON.
- -DENABLE_P4C_GRAPHS=ON|OFF. Enable the p4c-graphs backend. Default ON.
- -DENABLE_P4TEST=ON|OFF. Enable the p4test backend. Default ON.
- -DENABLE_TEST_TOOLS=ON|OFF. Enable the p4tools backend. Default OFF.
- -DENABLE_DOCS=ON|OFF. Build documentation. Default is OFF.
- -DENABLE_GC=ON|OFF. Enable the use of the garbage collection library. Default is ON.
- -DENABLE_GTESTS=ON|OFF. Enable building and running GTest unit tests. Default is ON.
- -DP4C_USE_PREINSTALLED_ABSEIL=ON|OFF. Try to find a system version of Abseil instead of a fetched one. Default is OFF.
- -DP4C_USE_PREINSTALLED_PROTOBUF=ON|OFF. Try to find a system version of Protobuf instead of a CMake version. Default is OFF.
- -DENABLE_ABSEIL_STATIC=ON|OFF. Enable the use of static abseil libraries. Default is ON. Only has an effect when P4C_USE_PREINSTALLED_ABSEIL is enabled.
- -DENABLE_PROTOBUF_STATIC=ON|OFF. Enable the use of static protobuf libraries. Default is ON. Only has an effect when P4C_USE_PREINSTALLED_PROTOBUF is enabled.
- -DENABLE_MULTITHREAD=ON|OFF. Use multithreading. Default is OFF.
- -DBUILD_LINK_WITH_GOLD=ON|OFF. Use Gold linker for build if available.
- -DBUILD_LINK_WITH_LLD=ON|OFF. Use LLD linker for build if available (overrides BUILD_LINK_WITH_GOLD).
- -DENABLE_LTO=ON|OFF. Use Link Time Optimization (LTO). Default is OFF.
- -DENABLE_WERROR=ON|OFF. Treat warnings as errors. Default is OFF.
- -DCMAKE_UNITY_BUILD=ON|OFF . Enable unity builds for faster compilation. Default is OFF.
If adding new targets to this build system, please see instructions.
(Optional) Install the compiler and the P4 shared headers globally.
```
sudo make install
```
The compiler driver p4c and binaries for each of the backends are installed in /usr/local/bin by default; the P4 headers are placed in /usr/local/share/p4c.
You're ready to go! You should be able to compile a P4-16 program for BMV2 using:
```
p4c -b bmv2-ss-p4org program.p4 -o program.bmv2.json
```