check_logical_instead_of_bitwise.c

   1 /*
   2  * sparse/check_logical_instead_of_bitwise.c
   3  *
   4  * Copyright (C) 2012 Oracle.
   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_bitshift(struct expression *expr)
  15 {
  16         expr = strip_expr(expr);
  17
  18         if (expr->type != EXPR_BINOP)
  19                 return 0;
  20         if (expr->op == SPECIAL_LEFTSHIFT || expr->op == SPECIAL_RIGHTSHIFT)
  21                 return 1;
  22         return 0;
  23 }
  24
  25 static void match_logic(struct expression *expr)
  26 {
  27         sval_t sval;
  28
  29         if (expr->type != EXPR_LOGICAL)
  30                 return;
  31
  32         if (get_macro_name(expr->pos))
  33                 return;
  34
  35         if (!get_value_sval(expr->right, &sval)) {
  36                 if (!get_value_sval(expr->left, &sval))
  37                         return;
  38         }
  39
  40         if (sval.value == 0 || sval.value == 1)
  41                 return;
  42
  43         sm_msg("warn: should this be a bitwise op?");
  44 }
  45
  46 static void match_assign(struct expression *expr)
  47 {
  48         struct expression *right;
  49
  50         right = strip_expr(expr->right);
  51         if (right->type != EXPR_LOGICAL)
  52                 return;
  53         if (is_bitshift(right->left) || is_bitshift(right->right))
  54                 sm_msg("warn: should this be a bitwise op?");
  55 }
  56
  57 void check_logical_instead_of_bitwise(int id)
  58 {
  59         my_id = id;
  60
  61         add_hook(&match_logic, LOGIC_HOOK);
  62         add_hook(&match_assign, ASSIGNMENT_HOOK);
  63 }