ccache is a compiler cache. It speeds up recompilation of C/C++ code by caching previous compilations and detecting when the same compilation is being done again. This often results in a significant speedup in common compilations, especially when switching between branches. This page is about using ccache on Mac with clang and the NinjaBuild system.
In order to use ccache with clang, you need to use the current git HEAD, since the most recent version (3.1.9) doesn't contain the patch needed for using the chromium style plugin.
To install ccache with homebrew, use the following command:
brew install --HEAD ccache
You can also download and install yourself (with GNU automake, autoconf and libtool installed):
git clone git://git.samba.org/ccache.git cd ccache ./autogen.sh ./configure && make && make install
Make sure ccache can be found in your $PATH.
You can also just use the current released version of ccache (3.1.8 or 3.1.9) and disable the chromium style plugin with clang_use_chrome_plugins = false in your args.gn.
You just need to set the use_ccache variable. Do so like the following:
gn gen out-gn --args='cc_wrapper="ccache"'
In the build phase, the following environment variables must be set (assuming you are in chromium/src):
export CCACHE_CPP2=yes export CCACHE_SLOPPINESS=time_macros export PATH=`pwd`/third_party/llvm-build/Release+Asserts/bin:$PATH
Then you can just run ninja as normal:
ninja -C out/Release chrome
ccache -M <max size>. You can see a list of configuration options by calling ccache alone. * The default ccache directory is ~/.ccache. You might want to symlink it to another directory (for example, when using FileVault for your home directory).