Re: [PATCH v9 3/4] Add Cyclomatic complexity GCC plugin
From: Laura Abbott
Date: Tue Jun 14 2016 - 15:30:11 EST
On 05/23/2016 03:10 PM, Emese Revfy 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).
This has some weird interaction with ftrace. On x86
1) make mrproper
2) make defconfig
3) enable GCC_PLUGINS, GCC_PLUGIN_CYC_COMPLEXITY
4) enable FUNCTION_TRACER (it will select other options as well)
5) make && make modules
MODPOST 18 modules
ERROR: "__fentry__" [net/netfilter/xt_nat.ko] undefined!
ERROR: "__fentry__" [net/netfilter/xt_mark.ko] undefined!
ERROR: "__fentry__" [net/netfilter/xt_addrtype.ko] undefined!
ERROR: "__fentry__" [net/netfilter/xt_LOG.ko] undefined!
ERROR: "__fentry__" [net/netfilter/nf_nat_sip.ko] undefined!
ERROR: "__fentry__" [net/netfilter/nf_nat_irc.ko] undefined!
ERROR: "__fentry__" [net/netfilter/nf_nat_ftp.ko] undefined!
ERROR: "__fentry__" [net/netfilter/nf_nat.ko] undefined!
ERROR: "__fentry__" [net/netfilter/nf_log_common.ko] undefined!
ERROR: "__fentry__" [net/ipv6/netfilter/nf_log_ipv6.ko] undefined!
ERROR: "__fentry__" [net/ipv4/netfilter/nf_nat_masquerade_ipv4.ko] undefined!
ERROR: "__fentry__" [net/ipv4/netfilter/nf_nat_ipv4.ko] undefined!
ERROR: "__fentry__" [net/ipv4/netfilter/nf_log_ipv4.ko] undefined!
ERROR: "__fentry__" [net/ipv4/netfilter/nf_log_arp.ko] undefined!
ERROR: "__fentry__" [net/ipv4/netfilter/iptable_nat.ko] undefined!
ERROR: "__fentry__" [net/ipv4/netfilter/ipt_MASQUERADE.ko] undefined!
ERROR: "__fentry__" [fs/efivarfs/efivarfs.ko] undefined!
ERROR: "__fentry__" [drivers/thermal/x86_pkg_temp_thermal.ko] undefined!
scripts/Makefile.modpost:91: recipe for target '__modpost' failed
make[1]: *** [__modpost] Error 1
Verified with gcc-5.3.1 and gcc-6.1.1. You need to do a clean build
with 'make mrproper' first to see this. Subsequent builds will
succeed oddly enough. I suspect this
Thanks,
Laura
Signed-off-by: Emese Revfy <re.emese@xxxxxxxxx>
---
arch/Kconfig | 12 +++++
scripts/Makefile.gcc-plugins | 1 +
scripts/gcc-plugins/Makefile | 1 +
scripts/gcc-plugins/cyc_complexity_plugin.c | 73 +++++++++++++++++++++++++++++
4 files changed, 87 insertions(+)
create mode 100644 scripts/gcc-plugins/cyc_complexity_plugin.c
diff --git a/arch/Kconfig b/arch/Kconfig
index 2821cfe..74f0d63 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -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
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index bcc373d..b4a189c 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -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
diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
index a4c9341..c60ba4b 100644
--- a/scripts/gcc-plugins/Makefile
+++ b/scripts/gcc-plugins/Makefile
@@ -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
diff --git a/scripts/gcc-plugins/cyc_complexity_plugin.c b/scripts/gcc-plugins/cyc_complexity_plugin.c
new file mode 100644
index 0000000..34df974
--- /dev/null
+++ b/scripts/gcc-plugins/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;
+}