Module Name: src
Committed By: rillig
Date: Sat Jan 15 23:21:34 UTC 2022
Modified Files:
src/tests/usr.bin/xlint/lint1: msg_193.c msg_193.exp msg_249.c
msg_249.exp
src/usr.bin/xlint/lint1: cgram.y
Log Message:
lint: warn about unreachable null statements
This warning flags the second semicolon of 'return;;' as being
unreachable. It does not warn about these superfluous semicolons in
general though.
Seen in usr.bin/make/bmake_malloc.c.
To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 src/tests/usr.bin/xlint/lint1/msg_193.c
cvs rdiff -u -r1.14 -r1.15 src/tests/usr.bin/xlint/lint1/msg_193.exp
cvs rdiff -u -r1.8 -r1.9 src/tests/usr.bin/xlint/lint1/msg_249.c
cvs rdiff -u -r1.6 -r1.7 src/tests/usr.bin/xlint/lint1/msg_249.exp
cvs rdiff -u -r1.378 -r1.379 src/usr.bin/xlint/lint1/cgram.y
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/tests/usr.bin/xlint/lint1/msg_193.c
diff -u src/tests/usr.bin/xlint/lint1/msg_193.c:1.15 src/tests/usr.bin/xlint/lint1/msg_193.c:1.16
--- src/tests/usr.bin/xlint/lint1/msg_193.c:1.15 Sat Jan 15 22:12:35 2022
+++ src/tests/usr.bin/xlint/lint1/msg_193.c Sat Jan 15 23:21:34 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: msg_193.c,v 1.15 2022/01/15 22:12:35 rillig Exp $ */
+/* $NetBSD: msg_193.c,v 1.16 2022/01/15 23:21:34 rillig Exp $ */
# 3 "msg_193.c"
// Test for message: statement not reached [193]
@@ -658,12 +658,27 @@ lint_annotation_NOTREACHED(void)
}
/*
- * Since at least 2002, lint does not detect a double semicolon. See
- * cgram.y, expression_statement, T_SEMI.
+ * Since at least 2002 and before cgram.y 1.379 from 2022-01-16, lint did not
+ * detect a double semicolon. See cgram.y, expression_statement, T_SEMI.
*/
int
-test_empty_statement(int x)
+test_null_statement(void)
{
- /* TODO: expect+1: warning: statement not reachable [193] */
- return x > 0 ? x : -x;;
+ /*
+ * The following 2 semicolons are superfluous but lint doesn't warn
+ * about them. Probably it should. A null statement as part of a
+ * block-list has no use.
+ */
+ ;;
+
+ /*
+ * A stand-alone null statement, on the other hand, has its purpose.
+ * Without it, the 'for' loop would not be complete. The NetBSD
+ * style is to use 'continue;' instead of a simple ';'.
+ */
+ for (int i = 0; i < 10; i++)
+ ;
+
+ /* expect+1: warning: statement not reached [193] */
+ return 0;;
}
Index: src/tests/usr.bin/xlint/lint1/msg_193.exp
diff -u src/tests/usr.bin/xlint/lint1/msg_193.exp:1.14 src/tests/usr.bin/xlint/lint1/msg_193.exp:1.15
--- src/tests/usr.bin/xlint/lint1/msg_193.exp:1.14 Sun Aug 15 21:51:56 2021
+++ src/tests/usr.bin/xlint/lint1/msg_193.exp Sat Jan 15 23:21:34 2022
@@ -87,3 +87,4 @@ msg_193.c(597): warning: statement not r
msg_193.c(606): warning: statement not reached [193]
msg_193.c(627): warning: statement not reached [193]
msg_193.c(655): warning: statement not reached [193]
+msg_193.c(683): warning: statement not reached [193]
Index: src/tests/usr.bin/xlint/lint1/msg_249.c
diff -u src/tests/usr.bin/xlint/lint1/msg_249.c:1.8 src/tests/usr.bin/xlint/lint1/msg_249.c:1.9
--- src/tests/usr.bin/xlint/lint1/msg_249.c:1.8 Sat Jul 10 17:35:54 2021
+++ src/tests/usr.bin/xlint/lint1/msg_249.c Sat Jan 15 23:21:34 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: msg_249.c,v 1.8 2021/07/10 17:35:54 rillig Exp $ */
+/* $NetBSD: msg_249.c,v 1.9 2022/01/15 23:21:34 rillig Exp $ */
# 3 "msg_249.c"
// Test for message: syntax error '%s' [249]
@@ -28,6 +28,7 @@ int recover_from_rbrace;
void
function(void)
{
+ /* expect+2: warning: statement not reached [193] */
if (0)
;
); /* expect: syntax error ')' */
Index: src/tests/usr.bin/xlint/lint1/msg_249.exp
diff -u src/tests/usr.bin/xlint/lint1/msg_249.exp:1.6 src/tests/usr.bin/xlint/lint1/msg_249.exp:1.7
--- src/tests/usr.bin/xlint/lint1/msg_249.exp:1.6 Sat Jul 10 11:22:19 2021
+++ src/tests/usr.bin/xlint/lint1/msg_249.exp Sat Jan 15 23:21:34 2022
@@ -1,4 +1,5 @@
msg_249.c(10): error: syntax error '"' [249]
msg_249.c(19): error: syntax error '"' [249]
-msg_249.c(33): error: syntax error ')' [249]
-msg_249.c(58): error: syntax error 'member without type' [249]
+msg_249.c(33): warning: statement not reached [193]
+msg_249.c(34): error: syntax error ')' [249]
+msg_249.c(59): error: syntax error 'member without type' [249]
Index: src/usr.bin/xlint/lint1/cgram.y
diff -u src/usr.bin/xlint/lint1/cgram.y:1.378 src/usr.bin/xlint/lint1/cgram.y:1.379
--- src/usr.bin/xlint/lint1/cgram.y:1.378 Sun Dec 26 18:16:41 2021
+++ src/usr.bin/xlint/lint1/cgram.y Sat Jan 15 23:21:34 2022
@@ -1,5 +1,5 @@
%{
-/* $NetBSD: cgram.y,v 1.378 2021/12/26 18:16:41 christos Exp $ */
+/* $NetBSD: cgram.y,v 1.379 2022/01/15 23:21:34 rillig Exp $ */
/*
* Copyright (c) 1996 Christopher G. Demetriou. All Rights Reserved.
@@ -35,7 +35,7 @@
#include <sys/cdefs.h>
#if defined(__RCSID) && !defined(lint)
-__RCSID("$NetBSD: cgram.y,v 1.378 2021/12/26 18:16:41 christos Exp $");
+__RCSID("$NetBSD: cgram.y,v 1.379 2022/01/15 23:21:34 rillig Exp $");
#endif
#include <limits.h>
@@ -1731,6 +1731,7 @@ expression_statement: /* C99 6.8.3 */
seen_fallthrough = false;
}
| T_SEMI {
+ check_statement_reachable();
seen_fallthrough = false;
}
;
