check_deref_check.c

   1 /*
   2  * sparse/check_deref_check.c
   3  *
   4  * Copyright (C) 2009 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include "smatch.h"
  11 #include "smatch_extra.h"
  12
  13 static int my_id;
  14
  15 STATE(derefed);
  16
  17 static void underef(struct sm_state *sm, struct expression *mod_expr)
  18 {
  19         set_state(my_id, sm->name, sm->sym, &undefined);
  20 }
  21
  22 static void match_dereference(struct expression *expr)
  23 {
  24         if (expr->type != EXPR_PREOP)
  25                 return;
  26         if (getting_address())
  27                 return;
  28         expr = strip_expr(expr->unop);
  29         if (implied_not_equal(expr, 0))
  30                 return;
  31
  32         set_state_expr(my_id, expr, &derefed);
  33 }
  34
  35 static void set_param_dereferenced(struct expression *arg, char *unused)
  36 {
  37         if (implied_not_equal(arg, 0))
  38                 return;
  39         set_state_expr(my_id, arg, &derefed);
  40 }
  41
  42 static void match_condition(struct expression *expr)
  43 {
  44         struct sm_state *sm;
  45
  46         if (__in_pre_condition)
  47                 return;
  48
  49         if (get_macro_name(expr->pos))
  50                 return;
  51
  52         sm = get_sm_state_expr(my_id, expr);
  53         if (!sm || sm->state != &derefed)
  54                 return;
  55
  56         sm_msg("warn: variable dereferenced before check '%s' (see line %d)", sm->name, sm->line);
  57         set_state_expr(my_id, expr, &undefined);
  58 }
  59
  60 void check_deref_check(int id)
  61 {
  62         my_id = id;
  63         add_hook(&match_dereference, DEREF_HOOK);
  64         add_hook(&match_condition, CONDITION_HOOK);
  65         select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
  66         add_modification_hook(my_id, &underef);
  67 }