From: John Levon <john.levon@joyent.com>
To: smatch@vger.kernel.org
Cc: John Levon <john.levon@joyent.com>
Subject: [PATCH] Add check_all_func_returns
Date: Tue, 12 Nov 2019 22:56:52 +0000 [thread overview]
Message-ID: <1573599412-21404-1-git-send-email-john.levon@joyent.com> (raw)
This replaces functionality in "lint" that checked every function with a
non-void return is handled.
We cannot use GCC's functionality for this, since a "(void)" cast is not
sufficient to turn it off, and besides, we want this to be the default for
everything.
---
check_all_func_returns.c | 88 ++++++++++++++++++++++++++++++++++++++++
check_list.h | 3 ++
2 files changed, 91 insertions(+)
create mode 100644 check_all_func_returns.c
diff --git a/check_all_func_returns.c b/check_all_func_returns.c
new file mode 100644
index 00000000..f9d77449
--- /dev/null
+++ b/check_all_func_returns.c
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2018 Joyent, Inc.
+ *
+ * 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
+ */
+
+/*
+ * Like lint of old, check that every return value from every function is used.
+ * Casting to (void) will silence this check.
+ */
+
+#include "smatch.h"
+#include "smatch_slist.h"
+
+static void check_func_return(struct expression *expr)
+{
+ struct symbol *sym = get_real_base_type(get_type(expr->fn));
+ const char *func = expr_to_str(expr->fn);
+ struct statement *stmt;
+
+ if (sym == NULL) {
+ sm_error("unknown type for func '%s'", func);
+ return;
+ }
+
+ if (expr->type != EXPR_CALL) {
+ sm_error("func '%s' is not a call site", func);
+ return;
+ }
+
+ /*
+ * There is never any need to check these returns.
+ */
+ if (strcmp(func, "memcpy") == 0 ||
+ strcmp(func, "memmove") == 0 ||
+ strcmp(func, "memset") == 0)
+ return;
+
+ /*
+ * Closer to a policy here, but there seems very few cases where it's
+ * useful to check the return value of the standard printf() family
+ * outputting to stdout or stderr.
+ */
+ if (strcmp(func, "printf") == 0 || strcmp(func, "vprintf") == 0)
+ return;
+
+ if (strcmp(func, "fprintf") == 0 || strcmp(func, "vfprintf")) {
+ const char *arg0 = expr_to_str(get_argument_from_call_expr(expr->args, 0));
+
+ if (arg0 != NULL &&
+ (strcmp(arg0, "(&__iob[1])") == 0 ||
+ strcmp(arg0, "(&__iob[2])") == 0))
+ return;
+ }
+
+ /*
+ * Either we got the return type already (direct call),
+ * or we need to go one further (function pointer call)
+ */
+ if (sym == &void_ctype || (sym->type == SYM_FN &&
+ get_real_base_type(sym) == &void_ctype))
+ return;
+
+ stmt = last_ptr_list((struct ptr_list *)big_statement_stack);
+
+ if (stmt->type == STMT_EXPRESSION && stmt->expression == expr)
+ sm_error("unchecked function return '%s'", expr_to_str(expr->fn));
+}
+
+void check_all_func_returns(int id)
+{
+ if (option_project != PROJ_ILLUMOS_KERNEL &&
+ option_project != PROJ_ILLUMOS_USER)
+ return;
+
+ add_hook(&check_func_return, FUNCTION_CALL_HOOK);
+}
diff --git a/check_list.h b/check_list.h
index 564bd1c2..cc3ce853 100644
--- a/check_list.h
+++ b/check_list.h
@@ -198,6 +198,9 @@ CK(check_wine_WtoA)
CK(check_arm64_tagged)
+/* illumos specific */
+CK(check_all_func_returns)
+
#include "check_list_local.h"
CK(register_scope)
--
2.17.1
reply other threads:[~2019-11-12 23:15 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1573599412-21404-1-git-send-email-john.levon@joyent.com \
--to=john.levon@joyent.com \
--cc=smatch@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).