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Subject: |
_FORTIFY_SOURCE compilation error: Redefinition with GCC 4.7.3 under Gentoo |
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Date: |
Sun, 20 Oct 2013 17:54:51 +1030 |
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Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130911 Thunderbird/17.0.9 |
G'day,
I've been building the latest Git sources for GNU Grep on a Gentoo
system. Using GCC-4.6.3, the update/reload command:
git pull ; ./bootstrap ; ./configure ; make ; make check
works fine. However, if I switch to GCC-4.7.3, the compilation
fails when compiling lib/argmatch.o:
make all-am
make[3]: Entering directory `/home/grep-2.14/grep/lib'
CC argmatch.o
In file included from argmatch.c:22:0:
../config.h:72:0: error: "_FORTIFY_SOURCE" redefined [-Werror]
argmatch.c:1:0: note: this is the location of the previous definition
cc1: all warnings being treated as errors
make[3]: *** [argmatch.o] Error 1
make[3]: Leaving directory `/home/grep-2.14/grep/lib'
make[2]: *** [all] Error 2
Scrounging around on the 'net a bit, it seems that Debian and others are now
"#defining _FORTIFY_SOURCE 2" as a default preprocessor definition in the
latest releases of gcc, and this has flowed on to the Gentoo 4.7.3 version.
(I haven't checked intervening gcc versions.)
The collision happens because of a rule in configure.ac, where, if __OPTIMIZE__
is
defined and is true, then _FORTIFY_SOURCE=2 is defined. The code injected into
config.h does not expect that an earlier definition is present, and this causes
the conflict:
AH_VERBATIM([FORTIFY_SOURCE],
[/* Enable compile-time and run-time bounds-checking, and some
warnings,
without upsetting glibc 2.15+. */
#if defined __OPTIMIZE__ && __OPTIMIZE__
# define _FORTIFY_SOURCE 2
#endif
])
I can suggest two ways of dealing with this: Either respect any previous
definition:
#if defined __OPTIMIZE__ && __OPTIMIZE__ && ! defined _FORTIFY_SOURCE
# define _FORTIFY_SOURCE 2
#endif
or, discard any previous directive and enforce fortification regardless:
#if defined __OPTIMIZE__ && __OPTIMIZE__
# undef _FORTIFY_SOURCE
# define _FORTIFY_SOURCE 2
#endif
It's probably worth sorting this out before releasing 2.15.
cheers,
behoffski (Brenton Hoff)
Programmer, Grouse Software
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--- Begin Message ---
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Subject: |
Re: bug#15663: _FORTIFY_SOURCE compilation error: Redefinition with GCC 4.7.3 under Gentoo |
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Date: |
Sun, 20 Oct 2013 15:06:57 -0700 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.0 |
behoffski wrote:
> I can suggest two ways of dealing with this: Either respect any previous
> definition:
That's what Emacs does, so I changed 'grep' to do that, as follows.
Thanks for reporting the bug.
>From 15e16023b8318b6eece1325eb2ea9d3fcfbc77ad Mon Sep 17 00:00:00 2001
From: Paul Eggert <address@hidden>
Date: Sun, 20 Oct 2013 15:05:14 -0700
Subject: [PATCH] build: port to platforms that predefine _FORTIFY_SOURCE
Problem reported by Brenton Hoff (Bug#15663).
* configure.ac (_FORTIFY_SOURCE): Don't define if already defined.
This is what Emacs does.
---
configure.ac | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/configure.ac b/configure.ac
index 5c93d04..6ce7237 100644
--- a/configure.ac
+++ b/configure.ac
@@ -159,7 +159,7 @@ if test "$gl_gcc_warnings" = yes; then
AH_VERBATIM([FORTIFY_SOURCE],
[/* Enable compile-time and run-time bounds-checking, and some warnings,
without upsetting glibc 2.15+. */
- #if defined __OPTIMIZE__ && __OPTIMIZE__
+ #if !defined _FORTIFY_SOURCE && defined __OPTIMIZE__ && __OPTIMIZE__
# define _FORTIFY_SOURCE 2
#endif
])
--
1.8.3.1
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