Date: Sun, 4 Dec 2005 01:04:31 +0200 From: Ruslan Ermilov <ru@FreeBSD.org> To: current@FreeBSD.org Cc: re@FreeBSD.org Subject: Re: Beware of subtle bugs due to cpp(1) limitations! Message-ID: <20051203230431.GL960@ip.net.ua> In-Reply-To: <20051203225517.GK960@ip.net.ua> References: <20051203224518.GJ960@ip.net.ua> <20051203225517.GK960@ip.net.ua>
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On Sun, Dec 04, 2005 at 12:55:17AM +0200, Ruslan Ermilov wrote:
> On Sun, Dec 04, 2005 at 12:45:18AM +0200, Ruslan Ermilov wrote:
> > Hi there,
> >
> > cpp(1) only supports integer expressions, so the following
> >
> > #define FOO foo
> > #if FOO == bar
> >
> > will always evaluate to true, because "foo" and "bar" will
> > be treated as zeroes, as explained in cpp.info.
[...]
> > The season for more bugs of this type is declared open! :-)
> >
> ``cpp -Wundef'' will allow us to find all these bugs.
>
Here we go:
%%%
Index: share/mk/bsd.sys.mk
===================================================================
RCS file: /home/ncvs/src/share/mk/bsd.sys.mk,v
retrieving revision 1.37
diff -u -r1.37 bsd.sys.mk
--- share/mk/bsd.sys.mk 16 Jan 2005 21:18:16 -0000 1.37
+++ share/mk/bsd.sys.mk 3 Dec 2005 22:57:36 -0000
@@ -11,7 +11,7 @@
.if !defined(NO_WARNS) && ${CC} != "icc"
. if defined(WARNS)
. if ${WARNS} >= 1
-CWARNFLAGS += -Wsystem-headers
+CWARNFLAGS += -Wsystem-headers -Wundef
. if !defined(NO_WERROR)
CWARNFLAGS += -Werror
. endif
Index: sys/conf/kern.mk
===================================================================
RCS file: /home/ncvs/src/sys/conf/kern.mk,v
retrieving revision 1.46
diff -u -r1.46 kern.mk
--- sys/conf/kern.mk 15 Jul 2005 11:45:30 -0000 1.46
+++ sys/conf/kern.mk 3 Dec 2005 22:58:41 -0000
@@ -12,7 +12,7 @@
.else
CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
-Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
- -fformat-extensions -std=c99
+ -Wundef -fformat-extensions -std=c99
.endif
#
# The following flags are next up for working on:
%%%
Should I commit it to force a thorough fixing?
(The #ifdef notdef/notyet are not affected by this change.)
Cheers,
--
Ruslan Ermilov
ru@FreeBSD.org
FreeBSD committer
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