check_precedence.c

   1 /*
   2  * sparse/check_precedence.c
   3  *
   4  * Copyright (C) 2010 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include "smatch.h"
  11
  12 static int my_id;
  13
  14 static int is_bool(struct expression *expr)
  15 {
  16         struct symbol *type;
  17
  18         type = get_type(expr);
  19         if (!type)
  20                 return 0;
  21         if (type->bit_size == 1 && type->ctype.modifiers & MOD_UNSIGNED)
  22                 return 1;
  23         return 0;
  24 }
  25
  26 static int is_bool_op(struct expression *expr)
  27 {
  28         expr = strip_expr(expr);
  29
  30         if (expr->type == EXPR_PREOP && expr->op == '!')
  31                 return 1;
  32         if (expr->type == EXPR_COMPARE)
  33                 return 1;
  34         if (expr->type == EXPR_LOGICAL)
  35                 return 1;
  36         return is_bool(expr);
  37 }
  38
  39 static void match_condition(struct expression *expr)
  40 {
  41         int print = 0;
  42
  43         if (expr->type == EXPR_COMPARE) {
  44                 if (expr->left->type == EXPR_COMPARE || expr->right->type == EXPR_COMPARE)
  45                         print = 1;
  46                 if (expr->left->op == '!') {
  47                         if (expr->left->type == EXPR_PREOP && expr->left->unop->op == '!')
  48                                 return;
  49                         if (expr->right->op == '!')
  50                                 return;
  51                         if (is_bool(expr->right))
  52                                 return;
  53                         if (is_bool(expr->left->unop))
  54                                 return;
  55                         print = 1;
  56                 }
  57         }
  58
  59         if (expr->type == EXPR_BINOP) {
  60                 if (expr->left->type == EXPR_COMPARE || expr->right->type == EXPR_COMPARE)
  61                         print = 1;
  62         }
  63
  64         if (print) {
  65                 sm_msg("warn: add some parenthesis here?");
  66                 return;
  67         }
  68
  69         if (expr->type == EXPR_BINOP && expr->op == '&') {
  70                 int i = 0;
  71
  72                 if (is_bool_op(expr->left))
  73                         i++;
  74                 if (is_bool_op(expr->right))
  75                         i++;
  76                 if (i == 1)
  77                         sm_msg("warn: maybe use && instead of &");
  78         }
  79 }
  80
  81 static void match_binop(struct expression *expr)
  82 {
  83         if (expr->op != '&')
  84                 return;
  85         if (expr->left->op == '!')
  86                 sm_msg("warn: add some parenthesis here?");
  87 }
  88
  89 void check_precedence(int id)
  90 {
  91         my_id = id;
  92
  93         add_hook(&match_condition, CONDITION_HOOK);
  94         add_hook(&match_binop, BINOP_HOOK);
  95 }