check_dereferences_param.c

   1 /*
   2  * sparse/check_dereferences_param.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 #include "smatch_extra.h"
  12 #include "smatch_slist.h"
  13
  14 static int my_id;
  15
  16 STATE(derefed);
  17 STATE(ignore);
  18 STATE(param);
  19
  20 static int is_arg(struct expression *expr)
  21 {
  22         struct symbol *arg;
  23
  24         if (expr->type != EXPR_SYMBOL)
  25                 return 0;
  26
  27         FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, arg) {
  28                 if (arg == expr->symbol)
  29                         return 1;
  30         } END_FOR_EACH_PTR(arg);
  31         return 0;
  32 }
  33
  34 static void set_ignore(struct sm_state *sm)
  35 {
  36         if (sm->state == &derefed)
  37                 return;
  38         set_state(my_id, sm->name, sm->sym, &ignore);
  39 }
  40
  41 static void match_function_def(struct symbol *sym)
  42 {
  43         struct symbol *arg;
  44         int i;
  45
  46         i = -1;
  47         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
  48                 i++;
  49                 if (!arg->ident)
  50                         continue;
  51                 set_state(my_id, arg->ident->name, arg, &param);
  52         } END_FOR_EACH_PTR(arg);
  53 }
  54
  55 static void check_deref(struct expression *expr)
  56 {
  57         struct sm_state *sm;
  58
  59         expr = strip_expr(expr);
  60
  61         if (!is_arg(expr))
  62                 return;
  63         if (implied_not_equal(expr, 0))
  64                 return;
  65
  66         sm = get_sm_state_expr(my_id, expr);
  67         if (sm && slist_has_state(sm->possible, &ignore))
  68                 return;
  69         set_state_expr(my_id, expr, &derefed);
  70 }
  71
  72 static void match_dereference(struct expression *expr)
  73 {
  74         if (expr->type != EXPR_PREOP)
  75                 return;
  76         if (getting_address())
  77                 return;
  78         check_deref(expr->unop);
  79 }
  80
  81 static void set_param_dereferenced(struct expression *arg, char *unused)
  82 {
  83         check_deref(arg);
  84 }
  85
  86 static void process_states(struct state_list *slist)
  87 {
  88         struct symbol *arg;
  89         int i;
  90
  91         i = -1;
  92         FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, arg) {
  93                 i++;
  94                 if (!arg->ident)
  95                         continue;
  96                 if (get_state_slist(slist, my_id, arg->ident->name, arg) == &derefed)
  97                         sm_msg("info: dereferences_param %d %s", i, global_static());
  98         } END_FOR_EACH_PTR(arg);
  99 }
 100
 101 void check_dereferences_param(int id)
 102 {
 103         if (!option_info)
 104                 return;
 105
 106         my_id = id;
 107
 108         add_hook(&match_function_def, FUNC_DEF_HOOK);
 109
 110         add_hook(&match_dereference, DEREF_HOOK);
 111         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
 112         add_modification_hook(my_id, &set_ignore);
 113
 114         all_return_states_hook(&process_states);
 115 }