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