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Commit 0dae776c authored by Emese Revfy's avatar Emese Revfy Committed by Michal Marek
Browse files

Add Cyclomatic complexity GCC plugin 



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: default avatarEmese Revfy <re.emese@gmail.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
parent 6b90bd4b

arch/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -372,6 +372,18 @@ menuconfig GCC_PLUGINS 


	  See Documentation/gcc-plugins.txt for details.



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

scripts/Makefile.gcc-plugins

+1 −0
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ ifdef CONFIG_GCC_PLUGINS 
  __PLUGINCC := $(call cc-ifversion, -ge, 0408, $(HOSTCXX), $(HOSTCC))

  PLUGINCC := $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-plugin.sh "$(__PLUGINCC)" "$(HOSTCXX)" "$(CC)")



  gcc-plugin-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY)	+= cyc_complexity_plugin.so

  GCC_PLUGINS_CFLAGS := $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y))



  export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN

scripts/gcc-plugins/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -17,4 +17,5 @@ export GCCPLUGINS_DIR HOSTLIBS 
$(HOSTLIBS)-y := $(GCC_PLUGIN)

always := $($(HOSTLIBS)-y)



cyc_complexity_plugin-objs := cyc_complexity_plugin.o

clean-files += *.so

scripts/gcc-plugins/cyc_complexity_plugin.c

0 → 100644
+73 −0
Original line number Diff line number Diff line 
/*

 * Copyright 2011-2016 by Emese Revfy <re.emese@gmail.com>

 * 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;

}