GCC plugin infrastructure


GCC plugins are loadable modules that provide extra features to the compiler [1]. They are useful for runtime instrumentation and static analysis. We can analyse, change and add further code during compilation via callbacks [2], GIMPLE [3], IPA [4] and RTL passes [5].

The GCC plugin infrastructure of the kernel supports building out-of-tree modules, cross-compilation and building in a separate directory. Plugin source files have to be compilable by a C++ compiler.

Currently the GCC plugin infrastructure supports only some architectures. Grep “select HAVE_GCC_PLUGINS” to find out which architectures support GCC plugins.

This infrastructure was ported from grsecurity [6] and PaX [7].




This is the directory of the GCC plugins.


This is a compatibility header for GCC plugins. It should be always included instead of individual gcc headers.

$(src)/scripts/gcc-plugins/gcc-generate-gimple-pass.h, $(src)/scripts/gcc-plugins/gcc-generate-ipa-pass.h, $(src)/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h, $(src)/scripts/gcc-plugins/gcc-generate-rtl-pass.h

These headers automatically generate the registration structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes. They should be preferred to creating the structures by hand.


You must install the gcc plugin headers for your gcc version, e.g., on Ubuntu for gcc-10:

apt-get install gcc-10-plugin-dev

Or on Fedora:

dnf install gcc-plugin-devel

Enable the GCC plugin infrastructure and some plugin(s) you want to use in the kernel config:


To compile the minimum tool set including the plugin(s):

make scripts

or just run the kernel make and compile the whole kernel with the cyclomatic complexity GCC plugin.

4. How to add a new GCC plugin

The GCC plugins are in scripts/gcc-plugins/. You need to put plugin source files right under scripts/gcc-plugins/. Creating subdirectories is not supported. It must be added to scripts/gcc-plugins/Makefile, scripts/Makefile.gcc-plugins and a relevant Kconfig file. See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin.