Add a very simple plugin to demonstrate the GCC plugin infrastructure. This GCC plugin computes the cyclomatic complexity of each function. The complexity M of a function's control flow graph is defined as: M = E - N + 2P where E = the number of edges N = the number of nodes P = the number of connected components (exit nodes). Signed-off-by: Emese Revfy <re.emese@xxxxxxxxx> --- arch/Kconfig | 12 +++++++ scripts/Makefile.gcc-plugins | 6 +++- tools/gcc/Makefile | 4 +++ tools/gcc/cyc_complexity_plugin.c | 73 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 94 insertions(+), 1 deletion(-) create mode 100644 tools/gcc/cyc_complexity_plugin.c diff --git a/arch/Kconfig b/arch/Kconfig index 4c54ef0..fa158b2 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -370,6 +370,18 @@ menuconfig GCC_PLUGINS GCC plugins are loadable modules that provide extra features to the compiler. They are useful for runtime instrumentation and static analysis. +config GCC_PLUGIN_CYC_COMPLEXITY + bool "Compute the cyclomatic complexity of a function" + depends on GCC_PLUGINS + help + The complexity M of a function's control flow graph is defined as: + M = E - N + 2P + where + + E = the number of edges + N = the number of nodes + P = the number of connected components (exit nodes). + config HAVE_CC_STACKPROTECTOR bool help diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index 7c85bf2..dd7b56d 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -5,7 +5,11 @@ else PLUGINCC := $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-plugin.sh "$(HOSTCC)" "$(HOSTCXX)" "$(CC)") endif ifneq ($(PLUGINCC),) -export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGINS_AFLAGS +ifdef CONFIG_GCC_PLUGIN_CYC_COMPLEXITY +GCC_PLUGIN_CYC_COMPLEXITY_CFLAGS := -fplugin=$(objtree)/tools/gcc/cyc_complexity_plugin.so +endif +GCC_PLUGINS_CFLAGS := $(GCC_PLUGIN_CYC_COMPLEXITY_CFLAGS) +export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGINS_AFLAGS GCC_PLUGIN_CYC_COMPLEXITY ifeq ($(KBUILD_EXTMOD),) gcc-plugins: $(Q)$(MAKE) $(build)=tools/gcc diff --git a/tools/gcc/Makefile b/tools/gcc/Makefile index b2d64af..31c72bf 100644 --- a/tools/gcc/Makefile +++ b/tools/gcc/Makefile @@ -12,4 +12,8 @@ endif export GCCPLUGINS_DIR HOSTLIBS +$(HOSTLIBS)-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) := cyc_complexity_plugin.so + always := $($(HOSTLIBS)-y) + +cyc_complexity_plugin-objs := cyc_complexity_plugin.o diff --git a/tools/gcc/cyc_complexity_plugin.c b/tools/gcc/cyc_complexity_plugin.c new file mode 100644 index 0000000..34df974 --- /dev/null +++ b/tools/gcc/cyc_complexity_plugin.c @@ -0,0 +1,73 @@ +/* + * Copyright 2011-2016 by Emese Revfy <re.emese@xxxxxxxxx> + * Licensed under the GPL v2, or (at your option) v3 + * + * Homepage: + * https://github.com/ephox-gcc-plugins/cyclomatic_complexity + * + * http://en.wikipedia.org/wiki/Cyclomatic_complexity + * The complexity M is then defined as: + * M = E - N + 2P + * where + * + * E = the number of edges of the graph + * N = the number of nodes of the graph + * P = the number of connected components (exit nodes). + * + * Usage (4.5 - 5): + * $ make clean; make run + */ + +#include "gcc-common.h" + +int plugin_is_GPL_compatible; + +static struct plugin_info cyc_complexity_plugin_info = { + .version = "20160225", + .help = "Cyclomatic Complexity\n", +}; + +static unsigned int cyc_complexity_execute(void) +{ + int complexity; + expanded_location xloc; + + /* M = E - N + 2P */ + complexity = n_edges_for_fn(cfun) - n_basic_blocks_for_fn(cfun) + 2; + + xloc = expand_location(DECL_SOURCE_LOCATION(current_function_decl)); + fprintf(stderr, "Cyclomatic Complexity %d %s:%s\n", complexity, + xloc.file, DECL_NAME_POINTER(current_function_decl)); + + return 0; +} + +#define PASS_NAME cyc_complexity + +#define NO_GATE +#define TODO_FLAGS_FINISH TODO_dump_func + +#include "gcc-generate-gimple-pass.h" + +int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version) +{ + const char * const plugin_name = plugin_info->base_name; + struct register_pass_info cyc_complexity_pass_info; + + cyc_complexity_pass_info.pass = make_cyc_complexity_pass(); + cyc_complexity_pass_info.reference_pass_name = "ssa"; + cyc_complexity_pass_info.ref_pass_instance_number = 1; + cyc_complexity_pass_info.pos_op = PASS_POS_INSERT_AFTER; + + if (!plugin_default_version_check(version, &gcc_version)) { + error(G_("incompatible gcc/plugin versions")); + return 1; + } + + register_callback(plugin_name, PLUGIN_INFO, NULL, + &cyc_complexity_plugin_info); + register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, + &cyc_complexity_pass_info); + + return 0; +} -- 2.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
