Joe,
Since commit 294f69e662d1("compiler_attributes.h: Add 'fallthrough' pseudo
keyword for switch/case use"), builds of VirtualBox are failing with the
following errors:
1954s] In file included from
/usr/src/linux-5.4.0-rc3-1.g2309d7d/include/linux/compiler_types.h:59,
[ 1954s] from <command-line>:
[ 1954s]
/home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/SUPDrvGip.c:
In function 'supdrvTscDeltaThread':
[ 1954s]
/usr/src/linux-5.4.0-rc3-1.g2309d7d/include/linux/compiler_attributes.h:200:41:
error: expected ')' before '__attribute__'
[ 1954s] 200 | # define fallthrough
__attribute__((__fallthrough__))
[ 1954s] | ^~~~~~~~~~~~~
[ 1954s]
/home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/include/iprt/cdefs.h:1169:44:
note: in expansion of macro 'fallthrough'
[ 1954s] 1169 | # define FALL_THROUGH __attribute__ ((fallthrough))
[ 1954s] | ^~~~~~~~~~~
[ 1954s]
/home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/include/iprt/cdefs.h:1176:33:
note: in expansion of macro 'FALL_THROUGH'
[ 1954s] 1176 | #define RT_FALL_THRU() FALL_THROUGH
[ 1954s] | ^~~~~~~~~~~~
[ 1954s]
/home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/SUPDrvGip.c:4192:17:
note: in expansion of macro 'RT_FALL_THRU'
[ 1954s] 4192 | RT_FALL_THRU();
[ 1954s] | ^~~~~~~~~~~~
[ 1954s] In file included from
/home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/include/VBox/cdefs.h:32,
[ 1954s] from
/home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/SUPDrvInternal.h:37,
[ 1954s] from
/home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/SUPDrvGip.c:33:
[ 1954s]
/home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/include/iprt/cdefs.h:1169:56:
error: expected identifier or '(' before ')' token
[ 1954s] 1169 | # define FALL_THROUGH __attribute__ ((fallthrough))
[ 1954s] | ^
[ 1954s]
/home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/include/iprt/cdefs.h:1176:33:
note: in expansion of macro 'FALL_THROUGH'
[ 1954s] 1176 | #define RT_FALL_THRU() FALL_THROUGH
[ 1954s] | ^~~~~~~~~~~~
I think the internal macros in the Oracle code are correct - at least they
worked before the patch in question was applied.
I would appreciate any suggestions.
Thanks,
Larry
On Tue, 2019-10-15 at 14:09 -0500, Larry Finger wrote:
> Joe,
Hey Larry.
> Since commit 294f69e662d1("compiler_attributes.h: Add 'fallthrough' pseudo
> keyword for switch/case use"), builds of VirtualBox are failing with the
> following errors:
>
> 1954s] In file included from
> /usr/src/linux-5.4.0-rc3-1.g2309d7d/include/linux/compiler_types.h:59,
> [ 1954s] from <command-line>:
> [ 1954s]
> /home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/SUPDrvGip.c:
> In function 'supdrvTscDeltaThread':
> [ 1954s]
> /usr/src/linux-5.4.0-rc3-1.g2309d7d/include/linux/compiler_attributes.h:200:41:
> error: expected ')' before '__attribute__'
> [ 1954s] 200 | # define fallthrough
> __attribute__((__fallthrough__))
> [ 1954s] | ^~~~~~~~~~~~~
> [ 1954s]
> /home/abuild/rpmbuild/BUILD/VirtualBox-6.0.12/modules_build_dir/default/vboxdrv/include/iprt/cdefs.h:1169:44:
> note: in expansion of macro 'fallthrough'
> [ 1954s] 1169 | # define FALL_THROUGH __attribute__ ((fallthrough))
Looks like this should be:
#define FALL_THROUGH __attribute__((__fallthrough__))
and there appear to be many of these #defines that
use __attribute__((foo)) where foo does not use the
double underscored prefix and suffix form
I also downloaded and trivially attempted to build vbox
without success, but I don't find this #define anywhere
in the sources. Clues?
$ git clone git://github.com/mirror/vbox.git
$ cd vbox
$ git grep FALL_THROUGH
$
$ ./configure
Checking for environment: Determined build machine: linux.amd64, target machine: linux.amd64, OK.
Checking for kBuild:
** kmk (variable KBUILDDIR) not found!
Check /home/joe/vbox/configure.log for details
$ cat configure.log
# Log file generated by
#
# './configure '
#
***** Checking environment *****
Determined build machine: linux.amd64, target machine: linux.amd64
***** Checking kBuild *****
** kmk (variable KBUILDDIR) not found!
$
On 10/15/19 2:32 PM, Joe Perches wrote:
>
> Hey Larry.
>
>
> Looks like this should be:
>
> #define FALL_THROUGH __attribute__((__fallthrough__))
>
> and there appear to be many of these #defines that
> use __attribute__((foo)) where foo does not use the
> double underscored prefix and suffix form
>
> I also downloaded and trivially attempted to build vbox
> without success, but I don't find this #define anywhere
> in the sources. Clues?
>
> $ git clone git://github.com/mirror/vbox.git
> $ cd vbox
>
> $ git grep FALL_THROUGH
> $
>
> $ ./configure
> Checking for environment: Determined build machine: linux.amd64, target machine: linux.amd64, OK.
> Checking for kBuild:
> ** kmk (variable KBUILDDIR) not found!
> Check /home/joe/vbox/configure.log for details
>
>
> $ cat configure.log
> # Log file generated by
> #
> # './configure '
> #
>
> ***** Checking environment *****
> Determined build machine: linux.amd64, target machine: linux.amd64
>
>
> ***** Checking kBuild *****
> ** kmk (variable KBUILDDIR) not found!
>
> $
I am the maintainer of VirtualBox for openSUSE, and it is their version that has
the problem.
The original code had the following macro definitions:
# define RT_FALL_THROUGH() __attribute__((fallthrough))
#define RT_FALL_THRU() RT_FALL_THROUGH()
The code uses both forms interchangeably. That failed - I think the () fooled
the compiler.
I replaced those with
#define FALL_THROUGH __attribute__((__fallthrough__))
#define RT_FALL_THRU() FALL_THROUGH
#define RT_FALL_THROUGH() FALL_THROUGH
My initial try was without the underscores around fallthrough, which caused a
conflict with the one in your changes. Putting them back resulted in code that
builds fine. Thanks for the help.
Larry