Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 ========================= 2 GCC plugin infrastructure 3 ========================= 4 5 6 Introduction 7 ============ 8 9 GCC plugins are loadable modules that provide extra features to the 10 compiler [1]_. They are useful for runtime instrumentation and static analysis. 11 We can analyse, change and add further code during compilation via 12 callbacks [2]_, GIMPLE [3]_, IPA [4]_ and RTL passes [5]_. 13 14 The GCC plugin infrastructure of the kernel supports all gcc versions from 15 4.5 to 6.0, building out-of-tree modules, cross-compilation and building in a 16 separate directory. 17 Plugin source files have to be compilable by both a C and a C++ compiler as well 18 because gcc versions 4.5 and 4.6 are compiled by a C compiler, 19 gcc-4.7 can be compiled by a C or a C++ compiler, 20 and versions 4.8+ can only be compiled by a C++ compiler. 21 22 Currently the GCC plugin infrastructure supports only the x86, arm, arm64 and 23 powerpc architectures. 24 25 This infrastructure was ported from grsecurity [6]_ and PaX [7]_. 26 27 -- 28 29 .. [1] https://gcc.gnu.org/onlinedocs/gccint/Plugins.html 30 .. [2] https://gcc.gnu.org/onlinedocs/gccint/Plugin-API.html#Plugin-API 31 .. [3] https://gcc.gnu.org/onlinedocs/gccint/GIMPLE.html 32 .. [4] https://gcc.gnu.org/onlinedocs/gccint/IPA.html 33 .. [5] https://gcc.gnu.org/onlinedocs/gccint/RTL.html 34 .. [6] https://grsecurity.net/ 35 .. [7] https://pax.grsecurity.net/ 36 37 38 Files 39 ===== 40 41 **$(src)/scripts/gcc-plugins** 42 43 This is the directory of the GCC plugins. 44 45 **$(src)/scripts/gcc-plugins/gcc-common.h** 46 47 This is a compatibility header for GCC plugins. 48 It should be always included instead of individual gcc headers. 49 50 **$(src)/scripts/gcc-plugin.sh** 51 52 This script checks the availability of the included headers in 53 gcc-common.h and chooses the proper host compiler to build the plugins 54 (gcc-4.7 can be built by either gcc or g++). 55 56 **$(src)/scripts/gcc-plugins/gcc-generate-gimple-pass.h, 57 $(src)/scripts/gcc-plugins/gcc-generate-ipa-pass.h, 58 $(src)/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h, 59 $(src)/scripts/gcc-plugins/gcc-generate-rtl-pass.h** 60 61 These headers automatically generate the registration structures for 62 GIMPLE, SIMPLE_IPA, IPA and RTL passes. They support all gcc versions 63 from 4.5 to 6.0. 64 They should be preferred to creating the structures by hand. 65 66 67 Usage 68 ===== 69 70 You must install the gcc plugin headers for your gcc version, 71 e.g., on Ubuntu for gcc-4.9:: 72 73 apt-get install gcc-4.9-plugin-dev 74 75 Enable a GCC plugin based feature in the kernel config:: 76 77 CONFIG_GCC_PLUGIN_CYC_COMPLEXITY = y 78 79 To compile only the plugin(s):: 80 81 make gcc-plugins 82 83 or just run the kernel make and compile the whole kernel with 84 the cyclomatic complexity GCC plugin. 85 86 87 4. How to add a new GCC plugin 88 ============================== 89 90 The GCC plugins are in $(src)/scripts/gcc-plugins/. You can use a file or a directory 91 here. It must be added to $(src)/scripts/gcc-plugins/Makefile, 92 $(src)/scripts/Makefile.gcc-plugins and $(src)/arch/Kconfig. 93 See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin.