check_iterator_outside_loop.c

   1 /*
   2  * Copyright (C) 2020 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_slist.h"
  20 #include "smatch_extra.h"
  21
  22 static int my_id;
  23
  24 STATE(iterator);
  25
  26 static void ok_to_use(struct sm_state *sm, struct expression *mod_expr)
  27 {
  28         set_state(my_id, sm->name, sm->sym, &undefined);
  29 }
  30
  31 static struct expression *get_iterator(struct statement *stmt)
  32 {
  33         struct expression *expr;
  34
  35         if (!stmt ||
  36             stmt->type != STMT_ITERATOR ||
  37             !stmt->iterator_pre_statement ||
  38             stmt->iterator_pre_statement->type != STMT_EXPRESSION)
  39                 return NULL;
  40
  41
  42         expr = strip_expr(stmt->iterator_pre_statement->expression);
  43         if (!expr || expr->type != EXPR_ASSIGNMENT)
  44                 return NULL;
  45
  46         return strip_expr(expr->left);
  47 }
  48
  49 static void match_loop(struct statement *stmt)
  50 {
  51         struct expression *pos;
  52         char *macro;
  53
  54         if (stmt->type != STMT_ITERATOR)
  55                 return;
  56         if (!stmt->iterator_pre_statement ||
  57             !stmt->iterator_pre_condition ||
  58             !stmt->iterator_post_statement)
  59                 return;
  60
  61         macro = get_macro_name(stmt->pos);
  62         if (!macro)
  63                 return;
  64         if (strncmp(macro, "list_for_each", strlen("list_for_each")) != 0)
  65                 return;
  66         pos = get_iterator(stmt);
  67         if (!pos)
  68                 return;
  69
  70         set_state_expr(my_id, pos, &iterator);
  71 }
  72
  73 static bool getting_prev_next(struct expression *expr)
  74 {
  75         struct expression *parent;
  76         int cnt = 0;
  77
  78         parent = expr;
  79         while ((parent = expr_get_parent_expr(parent))) {
  80                 if (parent->type == EXPR_PREOP && parent->op == '(')
  81                         continue;
  82                 if (parent->type == EXPR_DEREF &&
  83                     parent->member &&
  84                     (strcmp(parent->member->name, "prev") == 0 ||
  85                      strcmp(parent->member->name, "next") == 0))
  86                         return true;
  87                 if (cnt++ > 3)
  88                         break;
  89         }
  90
  91         return false;
  92 }
  93
  94 static void match_dereference(struct expression *expr)
  95 {
  96         struct expression *orig = expr;
  97         struct sm_state *sm;
  98         char *name;
  99
 100         if (expr->type == EXPR_PREOP && expr->op == '*')
 101                 expr = strip_expr(expr->unop);
 102
 103         sm = get_sm_state_expr(my_id, expr);
 104         if (!sm || !slist_has_state(sm->possible, &iterator))
 105                 return;
 106
 107         if (getting_prev_next(orig))
 108                 return;
 109
 110         name = expr_to_str(expr);
 111         sm_warning("iterator used outside loop: '%s'", name);
 112         free_string(name);
 113
 114         set_state_expr(my_id, expr, &undefined);
 115 }
 116
 117 void check_iterator_outside_loop(int id)
 118 {
 119         my_id = id;
 120
 121         if (option_project != PROJ_KERNEL)
 122                 return;
 123
 124         add_hook(match_loop, AFTER_LOOP_NO_BREAKS);
 125         add_modification_hook(my_id, &ok_to_use);
 126         add_hook(&match_dereference, DEREF_HOOK);
 127 }