Compilation Unit Addon

Compilation Units is a technique used to speed up compilation of huge projects, by regrouping compilation unit files (basically the .cpp and .c files) into a few big ones. Basically, instead of compiling foo.cpp and bar.cpp you compile a single foobaz.cpp one which contains the following :

#include "foo.cpp"
#include "bar.cpp"

This technique is based on the one known as Single Compilation Unit, but it allows creating N big compilation units, where N usually is the number of cores of your CPU. This allows you to take advantage of parallel compilation, while retaining the huge speed up introduced by the SCU technique.

How to use

Clone this repository some place where Premake will be able to locate. Then in your project's Premake script, include the main file like this :

require( "premake-compilationunit/compilationunit.lua" )

Then in the projects where you want to enable support for compilation units :

compilationunitenabled ( true )

The final step is to invoke Premake using the compilationunit option:

premake5 --compilationunit=8 <action>

Here I tell the module to use 8 compilation unit files, for projects where it has been enabled.

API

Most of the API commands of this addon are scoped to the current configuration, so unless specified otherwise, assume that the documented command only applies to the current configuration block.

compilationunitenabled enabled

Enable or disable the compilation unit generation for the current filter. enabled is a boolean.

compilationunitdir "path"

The path where the compilation unit files will be generated. If not specified, the obj dir will be used. This is a per-project configuration. The addon takes care of handling the various configurations for you.