smatch_dereference.c

   1 /*
   2  * Copyright (C) 2021 Oracle.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 #include "smatch.h"
  19 #include "smatch_extra.h"
  20
  21 static int my_id;
  22 static struct expr_fn_list *deref_hooks;
  23
  24 void add_dereference_hook(expr_func *fn)
  25 {
  26         add_ptr_list(&deref_hooks, fn);
  27 }
  28
  29 static void call_deref_hooks(struct expression *expr)
  30 {
  31         if (__in_fake_assign || __in_fake_parameter_assign)
  32                 return;
  33         if (!expr)
  34                 return;
  35
  36         call_expr_fns(deref_hooks, expr);
  37 }
  38
  39 static void match_dereference(struct expression *expr)
  40 {
  41         if (expr->type != EXPR_PREOP ||
  42             expr->op != '*')
  43                 return;
  44         expr = strip_expr(expr->unop);
  45         if (!is_pointer(expr))
  46                 return;
  47         call_deref_hooks(expr);
  48 }
  49
  50 static void match_pointer_as_array(struct expression *expr)
  51 {
  52         if (!is_array(expr))
  53                 return;
  54         call_deref_hooks(get_array_base(expr));
  55 }
  56
  57 static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
  58 {
  59         struct expression *deref;
  60
  61         deref = gen_expression_from_key(arg, key);
  62         if (!deref)
  63                 return;
  64
  65         call_deref_hooks(deref);
  66 }
  67
  68 void register_dereferences(int id)
  69 {
  70         my_id = id;
  71
  72         add_hook(&match_dereference, DEREF_HOOK);
  73         add_hook(&match_pointer_as_array, OP_HOOK);
  74         select_return_implies_hook_early(DEREFERENCE, &set_param_dereferenced);
  75 }
  76