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)
  32                 return 0;
  33
  34         if (expr->type == EXPR_BINOP) {
  35                 if (expr->op == '&')
  36                         return 1;
  37                 if (expr->op == SPECIAL_RIGHTSHIFT)
  38                         return 1;
  39                 if (expr->op == '%')
  40                         return is_capped(expr->right);
  41                 if (!is_capped(expr->left))
  42                         return 0;
  43                 if (expr->op == '/')
  44                         return 1;
  45                 if (!is_capped(expr->right))
  46                         return 0;
  47                 return 1;
  48         }
  49         if (get_implied_max(expr, &val))
  50                 return 1;
  51         if (get_state_expr(my_id, expr) == &capped)
  52                 return 1;
  53         return 0;
  54 }
  55
  56 void set_param_capped_data(const char *name, struct symbol *sym, char *key, char *value)
  57 {
  58         char fullname[256];
  59
  60         if (strncmp(key, "$$", 2))
  61                 return;
  62         snprintf(fullname, 256, "%s%s", name, key + 2);
  63         set_state(my_id, fullname, sym, &capped);
  64 }
  65
  66 static void match_condition(struct expression *expr)
  67 {
  68         struct smatch_state *left_true = NULL;
  69         struct smatch_state *left_false = NULL;
  70         struct smatch_state *right_true = NULL;
  71         struct smatch_state *right_false = NULL;
  72
  73
  74         if (expr->type != EXPR_COMPARE)
  75                 return;
  76
  77         switch (expr->op) {
  78         case '<':
  79         case SPECIAL_LTE:
  80         case SPECIAL_UNSIGNED_LT:
  81         case SPECIAL_UNSIGNED_LTE:
  82                 left_true = &capped;
  83                 right_false = &capped;
  84                 break;
  85         case '>':
  86         case SPECIAL_GTE:
  87         case SPECIAL_UNSIGNED_GT:
  88         case SPECIAL_UNSIGNED_GTE:
  89                 left_false = &capped;
  90                 right_true = &capped;
  91                 break;
  92         case SPECIAL_EQUAL:
  93                 left_true = &capped;
  94                 right_true = &capped;
  95                 break;
  96         case SPECIAL_NOTEQUAL:
  97                 left_false = &capped;
  98                 right_false = &capped;
  99                 break;
 100
 101         default:
 102                 return;
 103         }
 104
 105         set_true_false_states_expr(my_id, expr->right, right_true, right_false);
 106         set_true_false_states_expr(my_id, expr->left, left_true, left_false);
 107 }
 108
 109 static void match_min_assign(const char *fn, struct expression *expr, void *unused)
 110 {
 111         set_state_expr(my_id, expr->left, &capped);
 112 }
 113
 114 static void match_assign(struct expression *expr)
 115 {
 116         if (is_capped(expr->right)) {
 117                 set_state_expr(my_id, expr->left, &capped);
 118         } else {
 119                 if (get_state_expr(my_id, expr->left))
 120                         set_state_expr(my_id, expr->left, &uncapped);
 121         }
 122 }
 123
 124 static void match_caller_info(struct expression *expr)
 125 {
 126         struct expression *tmp;
 127         char *func;
 128         int i;
 129
 130         func = get_fnptr_name(expr->fn);
 131         if (!func)
 132                 return;
 133
 134         i = 0;
 135         FOR_EACH_PTR(expr->args, tmp) {
 136                 if (is_capped(tmp))
 137                         sm_msg("info: passes capped_data %s %d '$$'", func, i);
 138                 i++;
 139         } END_FOR_EACH_PTR(tmp);
 140 }
 141
 142 static void struct_member_callback(char *fn, int param, char *printed_name, struct smatch_state *state)
 143 {
 144         if (state != &capped)
 145                 return;
 146         sm_msg("info: passes capped_data '%s' %d '%s'", fn, param, printed_name);
 147 }
 148
 149 void register_capped(int id)
 150 {
 151         my_id = id;
 152
 153         add_definition_db_callback(set_param_capped_data, CAPPED_DATA);
 154         add_hook(&match_condition, CONDITION_HOOK);
 155         add_hook(&match_assign, ASSIGNMENT_HOOK);
 156         add_macro_assign_hook("min", &match_min_assign, NULL);
 157         add_macro_assign_hook("min_t", &match_min_assign, NULL);
 158         if (option_info) {
 159                 add_hook(&match_caller_info, FUNCTION_CALL_HOOK);
 160                 add_member_info_callback(my_id, struct_member_callback);
 161         }
 162 }