check_units.c

   1 /*
   2  * Copyright (C) 2018 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
  23 static void check_mult(struct expression *expr)
  24 {
  25         struct smatch_state *left, *right;
  26         int bit_found = 0, byte_found = 0;
  27         char *name;
  28
  29         left = get_units(expr->left);
  30         right = get_units(expr->right);
  31
  32         if (left == &unit_bit || right == &unit_bit)
  33                 bit_found++;
  34         if (left == &unit_byte || right == &unit_byte)
  35                 byte_found++;
  36
  37         if (bit_found && byte_found) {
  38                 name = expr_to_str(expr);
  39                 sm_warning("multiplying bits * bytes '%s'", name);
  40                 free_string(name);
  41         }
  42 }
  43
  44 static void check_add_sub(struct expression *expr)
  45 {
  46         struct smatch_state *left, *right;
  47         struct symbol *type;
  48         char *str;
  49
  50         type = get_type(expr->left);
  51         if (type && (type->type == SYM_PTR || type->type == SYM_ARRAY))
  52                 return;
  53
  54         left = get_units(expr->left);
  55         right = get_units(expr->right);
  56
  57         if (!left || !right || left == right)
  58                 return;
  59         str = expr_to_str(expr);
  60         sm_warning("missing conversion: '%s' '%s %s %s'", str, left->name, show_special(expr->op), right->name);
  61         free_string(str);
  62 }
  63
  64 static void match_binop_check(struct expression *expr)
  65 {
  66         switch (expr->op) {
  67         case '+':
  68         case '-':
  69                 check_add_sub(expr);
  70                 return;
  71         case '*':
  72                 check_mult(expr);
  73                 return;
  74         }
  75 }
  76
  77 static void match_condition_check(struct expression *expr)
  78 {
  79         struct smatch_state *left, *right;
  80         char *str;
  81
  82         if (expr->type != EXPR_COMPARE)
  83                 return;
  84
  85         left = get_units(expr->left);
  86         right = get_units(expr->right);
  87
  88         if (!left || !right)
  89                 return;
  90         if (left == right)
  91                 return;
  92
  93         str = expr_to_str(expr);
  94         sm_msg("warn: comparing different units: '%s' '%s %s %s'", str, left->name, show_special(expr->op), right->name);
  95         free_string(str);
  96 }
  97
  98 void check_units(int id)
  99 {
 100         my_id = id;
 101
 102         if (!option_spammy)
 103                 return;
 104
 105         add_hook(&match_binop_check, BINOP_HOOK);
 106         add_hook(&match_condition_check, CONDITION_HOOK);
 107 }