linux/scripts/gcc-plugins/cyc_complexity_plugin.c
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   1/*
   2 * Copyright 2011-2016 by Emese Revfy <re.emese@gmail.com>
   3 * Licensed under the GPL v2, or (at your option) v3
   4 *
   5 * Homepage:
   6 * https://github.com/ephox-gcc-plugins/cyclomatic_complexity
   7 *
   8 * https://en.wikipedia.org/wiki/Cyclomatic_complexity
   9 * The complexity M is then defined as:
  10 * M = E - N + 2P
  11 * where
  12 *
  13 *  E = the number of edges of the graph
  14 *  N = the number of nodes of the graph
  15 *  P = the number of connected components (exit nodes).
  16 *
  17 * Usage (4.5 - 5):
  18 * $ make clean; make run
  19 */
  20
  21#include "gcc-common.h"
  22
  23__visible int plugin_is_GPL_compatible;
  24
  25static struct plugin_info cyc_complexity_plugin_info = {
  26        .version        = "20160225",
  27        .help           = "Cyclomatic Complexity\n",
  28};
  29
  30static unsigned int cyc_complexity_execute(void)
  31{
  32        int complexity;
  33        expanded_location xloc;
  34
  35        /* M = E - N + 2P */
  36        complexity = n_edges_for_fn(cfun) - n_basic_blocks_for_fn(cfun) + 2;
  37
  38        xloc = expand_location(DECL_SOURCE_LOCATION(current_function_decl));
  39        fprintf(stderr, "Cyclomatic Complexity %d %s:%s\n", complexity,
  40                xloc.file, DECL_NAME_POINTER(current_function_decl));
  41
  42        return 0;
  43}
  44
  45#define PASS_NAME cyc_complexity
  46
  47#define NO_GATE
  48#define TODO_FLAGS_FINISH TODO_dump_func
  49
  50#include "gcc-generate-gimple-pass.h"
  51
  52__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
  53{
  54        const char * const plugin_name = plugin_info->base_name;
  55
  56        PASS_INFO(cyc_complexity, "ssa", 1, PASS_POS_INSERT_AFTER);
  57
  58        if (!plugin_default_version_check(version, &gcc_version)) {
  59                error(G_("incompatible gcc/plugin versions"));
  60                return 1;
  61        }
  62
  63        register_callback(plugin_name, PLUGIN_INFO, NULL,
  64                                &cyc_complexity_plugin_info);
  65        register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL,
  66                                &cyc_complexity_pass_info);
  67
  68        return 0;
  69}
  70