Re: [PATCH] Warning fixes

[Colin D Bennett <colin@gibibit.com>]

On Wed, 06 Aug 2008 10:32:26 -0400
Pavel Roskin <proski@gnu.org> wrote:

> Quoting Colin D Bennett <colin@gibibit.com>:
> 
> > Along these lines, can we use a gcc option to turn off the
> > "trampoline requires executable stack" warnings that are generated
> > by the dozens? I looked for the option in the gcc manual and could
> > not find it.
> 
> Please quote the exact message.  What platform is it?  I haven't seen
> it.

I have been using gcc 4.2.4 on x86 Linux.  However, I just upgraded a
machine to gcc 4.3.1, and it looks like the trampoline warnings are not
produced by gcc 4.3.1... interesting.  But they certainly are on 4.2.4:
there are 103 trampoline warnings in all (see the end of this message).

> > I think that the trampoline warning is the main thing left holding
> > us back from a warning-free build.  (IIRC there may be some
> > strict-aliasing warnings too... but those can be fixed by fixing the
> > code.)

Ok, I checked and there are no strict aliasing warnings.  Good.

> Yes, either we should make the build less noisy by default, or we  
> should treat warnings as errors.  Or maybe both.

I agree.

Regards,
Colin


system info
-----------

x86 Linux; glibc 2.8; gcc 4.2.4; Gentoo.

$ gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured
with: /var/tmp/portage/sys-devel/gcc-4.2.4/work/gcc-4.2.4/configure
--prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/4.2.4
--includedir=/usr/lib/gcc/i686-pc-linux-gnu/4.2.4/include
--datadir=/usr/share/gcc-data/i686-pc-linux-gnu/4.2.4
--mandir=/usr/share/gcc-data/i686-pc-linux-gnu/4.2.4/man
--infodir=/usr/share/gcc-data/i686-pc-linux-gnu/4.2.4/info
--with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/4.2.4/include/g++-v4
--host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec
--enable-nls --without-included-gettext --with-system-zlib
--disable-checking --disable-werror --enable-secureplt
--disable-multilib --enable-libmudflap --disable-libssp
--disable-libgcj --with-arch=i686
--enable-languages=c,c++,treelang,fortran --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
Thread model: posix gcc version 4.2.4 (Gentoo 4.2.4 p1.0)


trampoline warnings
-------------------

../util/i386/pc/grub-setup.c:93: warning: generating trampoline in
object (requires executable stack) ../util/i386/pc/grub-setup.c:93:
warning: generating trampoline in object (requires executable
stack) ../util/i386/pc/grub-setup.c:93: warning: generating trampoline
in object (requires executable stack) ../util/biosdisk.c:748: warning:
generating trampoline in object (requires executable
stack) ../kern/device.c:85: warning: generating trampoline in object
(requires executable stack) ../kern/device.c:85: warning: generating
trampoline in object (requires executable
stack) ../kern/partition.c:90: warning: generating trampoline in object
(requires executable stack) ../kern/partition.c:59: warning: generating
trampoline in object (requires executable stack) ../fs/fshelp.c:58:
warning: generating trampoline in object (requires executable
stack) ../fs/affs.c:460: warning: generating trampoline in object
(requires executable stack) ../fs/ext2.c:736: warning: generating
trampoline in object (requires executable stack) ../fs/hfs.c:578:
warning: generating trampoline in object (requires executable
stack) ../fs/hfs.c:578: warning: generating trampoline in object
(requires executable stack) ../fs/hfs.c:509: warning: generating
trampoline in object (requires executable stack) ../fs/hfs.c:725:
warning: generating trampoline in object (requires executable
stack) ../fs/hfsplus.c:699: warning: generating trampoline in object
(requires executable stack) ../fs/hfsplus.c:886: warning: generating
trampoline in object (requires executable stack) ../fs/iso9660.c:355:
warning: generating trampoline in object (requires executable
stack) ../fs/iso9660.c:229: warning: generating trampoline in object
(requires executable stack) ../fs/iso9660.c:466: warning: generating
trampoline in object (requires executable stack) ../fs/iso9660.c:655:
warning: generating trampoline in object (requires executable
stack) ../fs/udf.c:772: warning: generating trampoline in object
(requires executable stack) ../fs/ntfs.c:860: warning: generating
trampoline in object (requires executable stack) ../fs/reiserfs.c:1270:
warning: generating trampoline in object (requires executable
stack) ../fs/sfs.c:531: warning: generating trampoline in object
(requires executable stack) ../fs/xfs.c:624: warning: generating
trampoline in object (requires executable stack) ../fs/afs.c:566:
warning: generating trampoline in object (requires executable
stack) ../partmap/pc.c:232: warning: generating trampoline in object
(requires executable stack) ../partmap/gpt.c:123: warning: generating
trampoline in object (requires executable
stack) ../util/biosdisk.c:748: warning: generating trampoline in object
(requires executable stack) ../kern/device.c:85: warning: generating
trampoline in object (requires executable stack) ../kern/device.c:85:
warning: generating trampoline in object (requires executable
stack) ../kern/partition.c:90: warning: generating trampoline in object
(requires executable stack) ../kern/partition.c:59: warning: generating
trampoline in object (requires executable stack) ../fs/affs.c:460:
warning: generating trampoline in object (requires executable
stack) ../fs/ext2.c:736: warning: generating trampoline in object
(requires executable stack) ../fs/hfs.c:578: warning: generating
trampoline in object (requires executable stack) ../fs/hfs.c:578:
warning: generating trampoline in object (requires executable
stack) ../fs/hfs.c:509: warning: generating trampoline in object
(requires executable stack) ../fs/hfs.c:725: warning: generating
trampoline in object (requires executable stack) ../fs/hfsplus.c:699:
warning: generating trampoline in object (requires executable
stack) ../fs/hfsplus.c:886: warning: generating trampoline in object
(requires executable stack) ../fs/iso9660.c:355: warning: generating
trampoline in object (requires executable stack) ../fs/iso9660.c:229:
warning: generating trampoline in object (requires executable
stack) ../fs/iso9660.c:466: warning: generating trampoline in object
(requires executable stack) ../fs/iso9660.c:655: warning: generating
trampoline in object (requires executable stack) ../fs/udf.c:772:
warning: generating trampoline in object (requires executable
stack) ../fs/ntfs.c:860: warning: generating trampoline in object
(requires executable stack) ../fs/reiserfs.c:1270: warning: generating
trampoline in object (requires executable stack) ../fs/sfs.c:531:
warning: generating trampoline in object (requires executable
stack) ../fs/xfs.c:624: warning: generating trampoline in object
(requires executable stack) ../fs/afs.c:566: warning: generating
trampoline in object (requires executable stack) ../partmap/pc.c:232:
warning: generating trampoline in object (requires executable
stack) ../partmap/apple.c:182: warning: generating trampoline in object
(requires executable stack) ../partmap/gpt.c:123: warning: generating
trampoline in object (requires executable stack) ../fs/fshelp.c:58:
warning: generating trampoline in object (requires executable
stack) ../kern/device.c:85: warning: generating trampoline in object
(requires executable stack) ../kern/device.c:85: warning: generating
trampoline in object (requires executable
stack) ../kern/partition.c:90: warning: generating trampoline in object
(requires executable stack) ../kern/partition.c:59: warning: generating
trampoline in object (requires executable stack) ../normal/main.c:200:
warning: generating trampoline in object (requires executable
stack) ../normal/menu_entry.c:972: warning: generating trampoline in
object (requires executable stack) ../loader/i386/bsd.c:250: warning:
generating trampoline in object (requires executable
stack) ../fs/fshelp.c:58: warning: generating trampoline in object
(requires executable stack) ../fs/ext2.c:736: warning: generating
trampoline in object (requires executable stack) ../fs/ntfs.c:860:
warning: generating trampoline in object (requires executable
stack) ../fs/hfs.c:578: warning: generating trampoline in object
(requires executable stack) ../fs/hfs.c:578: warning: generating
trampoline in object (requires executable stack) ../fs/hfs.c:509:
warning: generating trampoline in object (requires executable
stack) ../fs/hfs.c:725: warning: generating trampoline in object
(requires executable stack) ../fs/iso9660.c:355: warning: generating
trampoline in object (requires executable stack) ../fs/iso9660.c:229:
warning: generating trampoline in object (requires executable
stack) ../fs/iso9660.c:466: warning: generating trampoline in object
(requires executable stack) ../fs/iso9660.c:655: warning: generating
trampoline in object (requires executable stack) ../fs/xfs.c:624:
warning: generating trampoline in object (requires executable
stack) ../fs/affs.c:460: warning: generating trampoline in object
(requires executable stack) ../fs/sfs.c:531: warning: generating
trampoline in object (requires executable stack) ../fs/hfsplus.c:699:
warning: generating trampoline in object (requires executable
stack) ../fs/hfsplus.c:886: warning: generating trampoline in object
(requires executable stack) ../fs/reiserfs.c:1270: warning: generating
trampoline in object (requires executable stack) ../fs/udf.c:772:
warning: generating trampoline in object (requires executable
stack) ../fs/afs.c:566: warning: generating trampoline in object
(requires executable stack) ../partmap/amiga.c:146: warning: generating
trampoline in object (requires executable
stack) ../partmap/apple.c:182: warning: generating trampoline in object
(requires executable stack) ../partmap/pc.c:232: warning: generating
trampoline in object (requires executable stack) ../partmap/sun.c:149:
warning: generating trampoline in object (requires executable
stack) ../partmap/gpt.c:123: warning: generating trampoline in object
(requires executable stack) ../commands/terminal.c:29: warning:
generating trampoline in object (requires executable
stack) ../commands/ls.c:45: warning: generating trampoline in object
(requires executable stack) ../commands/ls.c:66: warning: generating
trampoline in object (requires executable stack) ../commands/ls.c:66:
warning: generating trampoline in object (requires executable
stack) ../commands/help.c:30: warning: generating trampoline in object
(requires executable stack) ../commands/help.c:30: warning: generating
trampoline in object (requires executable
stack) ../commands/search.c:96: warning: generating trampoline in
object (requires executable stack) ../commands/search.c:42: warning:
generating trampoline in object (requires executable
stack) ../commands/search.c:150: warning: generating trampoline in
object (requires executable stack) ../disk/fs_uuid.c:31: warning:
generating trampoline in object (requires executable
stack) ../commands/blocklist.c:32: warning: generating trampoline in
object (requires executable stack) ../commands/loadenv.c:157: warning:
generating trampoline in object (requires executable
stack) ../kern/elf.c:399: warning: generating trampoline in object
(requires executable stack) ../kern/elf.c:355: warning: generating
trampoline in object (requires executable stack) ../kern/elf.c:221:
warning: generating trampoline in object (requires executable
stack) ../kern/elf.c:177: warning: generating trampoline in object
(requires executable stack)