[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAGXu5jJb4aJKQDTscJqUve6tO4S=5zU+X7ZGw87MfDoFMQSxLw@mail.gmail.com>
Date: Mon, 8 Feb 2016 20:23:12 -0800
From: Kees Cook <keescook@...omium.org>
To: Emese Revfy <re.emese@...il.com>
Cc: linux-kbuild <linux-kbuild@...r.kernel.org>, PaX Team <pageexec@...email.hu>,
Brad Spengler <spender@...ecurity.net>,
"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>, Michal Marek <mmarek@...e.com>
Subject: Re: [PATCH 2/3] Add Cyclomatic complexity GCC plugin
On Sun, Feb 7, 2016 at 1:31 PM, Emese Revfy <re.emese@...il.com> wrote:
> 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).
>
> ---
> Makefile | 6 +-
> arch/Kconfig | 16 +++++
> tools/gcc/Makefile | 4 ++
> tools/gcc/cyc_complexity_plugin.c | 120 ++++++++++++++++++++++++++++++++++++++
> 4 files changed, 145 insertions(+), 1 deletion(-)
> create mode 100644 tools/gcc/cyc_complexity_plugin.c
>
> diff --git a/Makefile b/Makefile
> index 96ce015..9f76c26 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -628,7 +628,11 @@ 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 -DGCC_PLUGIN_CYC_COMPLEXITY
> +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) $(build)=tools/gcc
> diff --git a/arch/Kconfig b/arch/Kconfig
> index a95e5b1..6b7d4de 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -365,6 +365,22 @@ config HAVE_GCC_PLUGINS
> An arch should select this symbol if it supports building with
> gcc plugins.
>
> +if HAVE_GCC_PLUGINS
> +
> +config GCC_PLUGIN_CYC_COMPLEXITY
> + bool "Compute the cyclomatic complexity of a function"
> + help
Rather than the "if HAVE_GCC_PLUGINS" / endif section, I would add
"depends HAVE_GCC_PLUGINS" to the config, which makes things more
discoverable.
> + The complexity M of a function's control flow graph is defined as:
> + M = E - N + 2P
> + where
> +
> + E = the number of edges
> + N = the number of nodes
> + P = the number of connected components (exit nodes).
> +
> + See Documentation/gcc-plugins.txt for details.
Is this plugin documented there? I don't see a chunk for that in this patch.
> +
> +endif # HAVE_GCC_PLUGINS
> endmenu # "GCC plugins"
>
> config HAVE_CC_STACKPROTECTOR
> diff --git a/tools/gcc/Makefile b/tools/gcc/Makefile
> index b2d64af..31c72bf 100644
> --- a/tools/gcc/Makefile
> +++ b/tools/gcc/Makefile
> @@ -12,4 +12,8 @@ endif
>
> export GCCPLUGINS_DIR HOSTLIBS
>
> +$(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..c6f0d58
> --- /dev/null
> +++ b/tools/gcc/cyc_complexity_plugin.c
> @@ -0,0 +1,120 @@
> +/*
> + * Copyright 2011-2016 by Emese Revfy <re.emese@...il.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 = "20150523",
> + .help = "Cyclomatic Complexity\n",
> +};
> +
> +static unsigned int handle_function(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;
> +}
> +
> +#if BUILDING_GCC_VERSION >= 4009
> +namespace {
> +static const struct pass_data cyc_complexity_pass_data = {
> +#else
> +static struct gimple_opt_pass cyc_complexity_pass = {
> + .pass = {
> +#endif
> + .type = GIMPLE_PASS,
> + .name = "cyc_complexity",
> +#if BUILDING_GCC_VERSION >= 4008
> + .optinfo_flags = OPTGROUP_NONE,
> +#endif
> +#if BUILDING_GCC_VERSION >= 5000
> +#elif BUILDING_GCC_VERSION >= 4009
> + .has_gate = false,
> + .has_execute = true,
> +#else
> + .gate = NULL,
> + .execute = handle_function,
> + .sub = NULL,
> + .next = NULL,
> + .static_pass_number = 0,
> +#endif
> + .tv_id = TV_NONE,
> + .properties_required = 0,
> + .properties_provided = 0,
> + .properties_destroyed = 0,
> + .todo_flags_start = 0,
> + .todo_flags_finish = TODO_dump_func
> +#if BUILDING_GCC_VERSION < 4009
> + }
> +#endif
> +};
> +
> +#if BUILDING_GCC_VERSION >= 4009
> +class cyc_complexity_pass : public gimple_opt_pass {
> +public:
> + cyc_complexity_pass() : gimple_opt_pass(cyc_complexity_pass_data, g) {}
> +#if BUILDING_GCC_VERSION >= 5000
> + virtual unsigned int execute(function *) { return handle_function(); }
> +#else
> + unsigned int execute() { return handle_function(); }
> +#endif
> +};
> +}
> +
> +static struct opt_pass *make_cyc_complexity_pass(void)
> +{
> + return new cyc_complexity_pass();
> +}
> +#else
> +static struct opt_pass *make_cyc_complexity_pass(void)
> +{
> + return &cyc_complexity_pass.pass;
> +}
> +#endif
> +
> +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;
> +}
>
--
Kees Cook
Chrome OS & Brillo Security
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
