smatch_capped.c

   1 /*
   2  * smatch/smatch_capped.c
   3  *
   4  * Copyright (C) 2011 Oracle.  All rights reserved.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * This is trying to make a list of the variables which
  12  * have capped values.  Sometimes we don't know what the
  13  * cap is, for example if we are comparing variables but
  14  * we don't know the values of the variables.  In that
  15  * case we only know that our variable is capped and we
  16  * sort that information here.
  17  */
  18
  19 #include "smatch.h"
  20 #include "smatch_slist.h"
  21
  22 static int my_id;
  23
  24 STATE(capped);
  25 STATE(uncapped);
  26
  27 int is_capped(struct expression *expr)
  28 {
  29         long long val;
  30
  31         if (expr->type == EXPR_BINOP) {
  32                 if (expr->op == '&')
  33                         return 1;
  34                 if (expr->op == SPECIAL_RIGHTSHIFT)
  35                         return 1;
  36                 if (expr->op == '%')
  37                         return is_capped(expr->right);
  38                 if (!is_capped(expr->left))
  39                         return 0;
  40                 if (expr->op == '/')
  41                         return 1;
  42                 if (!is_capped(expr->right))
  43                         return 0;
  44                 return 1;
  45         }
  46         if (get_implied_max(expr, &val))
  47                 return 1;
  48         if (get_state_expr(my_id, expr) == &capped)
  49                 return 1;
  50         return 0;
  51 }
  52
  53 void set_param_capped_data(const char *name, struct symbol *sym, char *key, char *value)
  54 {
  55         char fullname[256];
  56
  57         if (strncmp(key, "$$", 2))
  58                 return;
  59         snprintf(fullname, 256, "%s%s", name, key + 2);
  60         set_state(my_id, fullname, sym, &capped);
  61 }
  62
  63 static void match_condition(struct expression *expr)
  64 {
  65         struct smatch_state *left_true = NULL;
  66         struct smatch_state *left_false = NULL;
  67         struct smatch_state *right_true = NULL;
  68         struct smatch_state *right_false = NULL;
  69
  70
  71         if (expr->type != EXPR_COMPARE)
  72                 return;
  73
  74         switch (expr->op) {
  75         case '<':
  76         case SPECIAL_LTE:
  77         case SPECIAL_UNSIGNED_LT:
  78         case SPECIAL_UNSIGNED_LTE:
  79                 left_true = &capped;
  80                 right_false = &capped;
  81                 break;
  82         case '>':
  83         case SPECIAL_GTE:
  84         case SPECIAL_UNSIGNED_GT:
  85         case SPECIAL_UNSIGNED_GTE:
  86                 left_false = &capped;
  87                 right_true = &capped;
  88                 break;
  89         case SPECIAL_EQUAL:
  90                 left_true = &capped;
  91                 right_true = &capped;
  92                 break;
  93         case SPECIAL_NOTEQUAL:
  94                 left_false = &capped;
  95                 right_false = &capped;
  96                 break;
  97
  98         default:
  99                 return;
 100         }
 101
 102         set_true_false_states_expr(my_id, expr->right, right_true, right_false);
 103         set_true_false_states_expr(my_id, expr->left, left_true, left_false);
 104 }
 105
 106 static void match_min_assign(const char *fn, struct expression *expr, void *unused)
 107 {
 108         set_state_expr(my_id, expr->left, &capped);
 109 }
 110
 111 static void match_assign(struct expression *expr)
 112 {
 113         if (is_capped(expr->right)) {
 114                 set_state_expr(my_id, expr->left, &capped);
 115         } else {
 116                 if (get_state_expr(my_id, expr->left))
 117                         set_state_expr(my_id, expr->left, &uncapped);
 118         }
 119 }
 120
 121 static void match_caller_info(struct expression *expr)
 122 {
 123         struct expression *tmp;
 124         char *func;
 125         int i;
 126
 127         func = get_fnptr_name(expr->fn);
 128         if (!func)
 129                 return;
 130
 131         i = 0;
 132         FOR_EACH_PTR(expr->args, tmp) {
 133                 if (is_capped(tmp))
 134                         sm_msg("info: passes capped_data %s %d '$$'", func, i);
 135                 i++;
 136         } END_FOR_EACH_PTR(tmp);
 137 }
 138
 139 static void struct_member_callback(char *fn, int param, char *printed_name, struct smatch_state *state)
 140 {
 141         if (state != &capped)
 142                 return;
 143         sm_msg("info: passes capped_data '%s' %d '%s'", fn, param, printed_name);
 144 }
 145
 146 void register_capped(int id)
 147 {
 148         my_id = id;
 149
 150         add_definition_db_callback(set_param_capped_data, CAPPED_DATA);
 151         add_hook(&match_condition, CONDITION_HOOK);
 152         add_hook(&match_assign, ASSIGNMENT_HOOK);
 153         add_macro_assign_hook("min", &match_min_assign, NULL);
 154         add_macro_assign_hook("min_t", &match_min_assign, NULL);
 155         if (option_info) {
 156                 add_hook(&match_caller_info, FUNCTION_CALL_HOOK);
 157                 add_member_info_callback(my_id, struct_member_callback);
 158         }
 159 }