smatch_param_used.c

   1 /*
   2  * Copyright (C) 2015 Oracle.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 #include "smatch.h"
  19 #include "smatch_slist.h"
  20
  21 static int my_id;
  22 int __ignore_param_used;
  23
  24 static struct stree *used_stree;
  25
  26 STATE(used);
  27
  28 static void get_state_hook(int owner, const char *name, struct symbol *sym)
  29 {
  30         static const char *prev;
  31         int arg;
  32
  33         if (!option_info)
  34                 return;
  35
  36         if (__ignore_param_used ||
  37             __in_fake_assign ||
  38             __in_fake_parameter_assign ||
  39             __in_function_def ||
  40             __in_unmatched_hook)
  41                 return;
  42
  43         if (!name || name[0] == '&')
  44                 return;
  45
  46         if (name == prev)
  47                 return;
  48         prev = name;
  49
  50         arg = get_param_num_from_sym(sym);
  51         if (arg < 0)
  52                 return;
  53         if (param_was_set_var_sym(name, sym))
  54                 return;
  55         if (parent_was_PARAM_CLEAR(name, sym))
  56                 return;
  57
  58         set_state_stree(&used_stree, my_id, name, sym, &used);
  59 }
  60
  61 static void set_param_used(struct expression *call, struct expression *arg, char *key, char *unused)
  62 {
  63         struct symbol *sym;
  64         char *name;
  65         int arg_nr;
  66
  67         if (!option_info)
  68                 return;
  69
  70         if (key[0] == '&')
  71                 return;
  72
  73         name = get_variable_from_key(arg, key, &sym);
  74         if (!name || !sym)
  75                 goto free;
  76
  77         arg_nr = get_param_num_from_sym(sym);
  78         if (arg_nr < 0)
  79                 goto free;
  80         if (param_was_set_var_sym(name, sym))
  81                 goto free;
  82         set_state_stree(&used_stree, my_id, name, sym, &used);
  83 free:
  84         free_string(name);
  85 }
  86
  87 static void process_states(void)
  88 {
  89         struct sm_state *tmp;
  90         int arg;
  91         const char *name;
  92
  93         FOR_EACH_SM(used_stree, tmp) {
  94                 arg = get_param_num_from_sym(tmp->sym);
  95                 if (arg < 0)
  96                         continue;
  97                 name = get_param_name(tmp);
  98                 if (!name)
  99                         continue;
 100                 if (strcmp(name, "$") == 0 ||
 101                     strcmp(name, "*$") == 0)
 102                         continue;
 103                 if (is_recursive_member(name))
 104                         continue;
 105
 106                 if (is_ignored_kernel_data(name))
 107                         continue;
 108
 109                 sql_insert_return_implies(PARAM_USED, arg, name, "");
 110         } END_FOR_EACH_SM(tmp);
 111
 112         free_stree(&used_stree);
 113 }
 114
 115 static void match_function_def(struct symbol *sym)
 116 {
 117         free_stree(&used_stree);
 118 }
 119
 120 void register_param_used(int id)
 121 {
 122         my_id = id;
 123
 124         add_hook(&match_function_def, AFTER_FUNC_HOOK);
 125         add_function_data((unsigned long *)&used_stree);
 126
 127         add_get_state_hook(&get_state_hook);
 128
 129         select_return_implies_hook(PARAM_USED, &set_param_used);
 130         all_return_states_hook(&process_states);
 131 }