Re: [PATCH] check_do_while_loop_limit: implements checker for do_while loops

[Dan Carpenter <dan.carpenter@oracle.com>]

On Mon, Jul 26, 2021 at 07:13:19PM +0530, Harshvardhan Jha wrote:
> do{} while(n--) loops end at n=-1 but programmers sometimes assume that
> they end at n=0. This checker sends a warning in these scenarios.
> 
> Signed-off-by: Harshvardhan Jha <harshvardhan.jha@oracle.com>
> ---
>  check_do_while_loop_limit.c | 67 +++++++++++++++++++++++++++++++++++++
>  check_list.h                |  1 +
>  2 files changed, 68 insertions(+)
>  create mode 100644 check_do_while_loop_limit.c
> 
> diff --git a/check_do_while_loop_limit.c b/check_do_while_loop_limit.c
> new file mode 100644
> index 00000000..9a492725
> --- /dev/null
> +++ b/check_do_while_loop_limit.c
> @@ -0,0 +1,67 @@
> +/*
> + * Copyright (C) 2021 Harshvardhan Jha.
                         ^^^^^^^^^^^^^^^^
This should be copyright Oracle (Harshvardhan has been working for
Oracle as an intern this summer).

> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
> + */
> +
> +#include "smatch.h"
> +#include "smatch_slist.h"
> +#include "smatch_extra.h"
> +
> +static int my_id;
> +
> +STATE(post_minus);
> +
> +static bool is_post_minus(struct expression *expr)
> +{
> +	expr = strip_expr(expr);
> +	if (!expr)
> +		return false;
> +	if (expr->type != EXPR_POSTOP)
> +		return false;
> +	if (expr->op != SPECIAL_DECREMENT)
> +		return false;
> +	return true;
> +}
> +
> +static void match_post_loop(struct expression *expr)
> +{
> +	struct statement *stmt;
> +
> +	expr = strip_expr(expr);
> +	stmt = expr_get_parent_stmt(expr);
> +
> +	if (!stmt)
> +		return;
> +	if (stmt->type != STMT_ITERATOR)
> +		return;
> +	if (!is_post_minus(stmt->iterator_post_condition))
> +		return;
> +	if (is_post_minus(stmt->iterator_post_condition))
> +		set_state_expr(my_id, stmt->iterator_post_condition->left, &post_minus);
> +}
> +
> +static void match_condition(struct expression *expr)
> +{
> +	if (get_state_expr(my_id, expr) != &post_minus)
> +		return;
> +	sm_warning("do while ends on '%s == -1'",expr_to_str(expr));
                                                 ^
Add a space after the comma.

> +}

regards,
dan carpenter