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