4:40 p.m.
I am trying to run the unit tests for an application (that is only
header files) in the%check section of the RPM spec file, running cmake
on both gcc and clang with %optflags macro on Fedora rawhide.
According to the guideline
https://docs.fedoraproject.org/en-US/packaging-guidelines/#_compiler_flags
, it seems %optflags macro works with both gcc and clang without the
restriction for a specific compiler.
This cmake command for gcc works.
```
CC=gcc CXX=g++ cmake .. \
-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON \
-DCMAKE_C_FLAGS="%{optflags}" \
-DCMAKE_CXX_FLAGS="%{optflags}"
%make_build
```
But this cmake command for clang does not work with the error
"clang-10: error: unknown argument: '-fstack-clash-protection'". The
used clang version is 10.0.0.
Should %{optflags} work for both gcc and clang? Is it a bug of the
%optflags macro?
```
CC=clang CXX=clang++ cmake .. \
-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON \
-DCMAKE_C_FLAGS="%{optflags}" \
-DCMAKE_CXX_FLAGS="%{optflags}"
%make_build
```
The log is here.
```
+ CC=clang
+ CXX=clang++
+ cmake .. -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON '-DCMAKE_C_FLAGS=-O2 -g
-pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
-Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong
-grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
-fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection'
'-DCMAKE_CXX_FLAGS=-O2 -g -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
-fstack-protector-strong -grecord-gcc-switches
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
-fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection'
-- The C compiler identification is Clang 10.0.0
-- The CXX compiler identification is Clang 10.0.0
-- Check for working C compiler: /usr/bin/clang
-- Check for working C compiler: /usr/bin/clang - broken
CMake Error at /usr/share/cmake/Modules/CMakeTestCCompiler.cmake:60 (message):
The C compiler
"/usr/bin/clang"
is not able to compile a simple test program.
It fails with the following output:
Change Dir:
/builddir/build/BUILD/simde-0d632e1e0bd0a258ce3d3e240fbec4dd71234819/test/build-clang/CMakeFiles/CMakeTmp
----
Run Build Command(s):/usr/bin/gmake cmTC_686bc/fast &&
/usr/bin/gmake -f CMakeFiles/cmTC_686bc.dir/build.make
CMakeFiles/cmTC_686bc.dir/build
gmake[1]: Entering directory
'/builddir/build/BUILD/simde-0d632e1e0bd0a258ce3d3e240fbec4dd71234819/test/build-clang/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_686bc.dir/testCCompiler.c.o
/usr/bin/clang -O2 -g -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
-fstack-protector-strong -grecord-gcc-switches
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
-fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection
-o CMakeFiles/cmTC_686bc.dir/testCCompiler.c.o -c
/builddir/build/BUILD/simde-0d632e1e0bd0a258ce3d3e240fbec4dd71234819/test/build-clang/CMakeFiles/CMakeTmp/testCCompiler.c
clang-10: error: unknown argument: '-fstack-clash-protection'
gmake[1]: *** [CMakeFiles/cmTC_686bc.dir/build.make:83:
CMakeFiles/cmTC_686bc.dir/testCCompiler.c.o] Error 1
gmake[1]: Leaving directory
'/builddir/build/BUILD/simde-0d632e1e0bd0a258ce3d3e240fbec4dd71234819/test/build-clang/CMakeFiles/CMakeTmp'
gmake: *** [Makefile:138: cmTC_686bc/fast] Error 2
```
Thanks.
--
Jun | He - His - Him
4:45 p.m.
On Sat, Apr 4, 2020 at 5:41 PM Jun Aruga <jaruga(a)redhat.com> wrote:
I am trying to run the unit tests for an application (that is only
header files) in the%check section of the RPM spec file, running cmake
on both gcc and clang with %optflags macro on Fedora rawhide.
According to the guideline
https://docs.fedoraproject.org/en-US/packaging-guidelines/#_compiler_flags
, it seems %optflags macro works with both gcc and clang without the
restriction for a specific compiler.
The compiler flags Fedora sets are not compatible with Clang without
you doing filtering. Unfortunately, Clang hasn't been very good at
implementing some of the security features that we rely on in Fedora
from the system compiler, and it also does not support the specs we
pass to force certain build and link behaviors. Finally, of course it
doesn't support annobin.
The specific flags enabled are documented here:
https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/buildf...
--
真実はいつも一つ！/ Always, there's only one truth!
11:59 a.m.
The compiler flags Fedora sets are not compatible with Clang without
you doing filtering. Unfortunately, Clang hasn't been very good at
implementing some of the security features that we rely on in Fedora
from the system compiler, and it also does not support the specs we
pass to force certain build and link behaviors. Finally, of course it
doesn't support annobin.
The specific flags enabled are documented here:
https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/buildf...
Thanks for sharing the info.
I confirmed that the following commands worked by filtering %optflags.
```
optflags_clang=$(echo "%{optflags}" | sed -e 's|
-fstack-clash-protection||' -e 's| -specs=[^ ]*||g')
CC=clang CXX=clang++ cmake .. \
-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON \
-DCMAKE_C_FLAGS="${optflags_clang}" \
-DCMAKE_CXX_FLAGS="${optflags_clang}"
%make_build
```
What do you think about adding the following macros in rpms/redhat-rpm-config?
I think it's useful for people who want to build their RPM package not
by gcc but for some reasons.
rpms/ruby might be the case to build with clang near feature, because
gcc's PIE is not compatible with Ruby's just-in-time (JIT) feature
using pre-compiler-header (PCH) [1].
```
%{build_clang_cflags}
%{build_clang_cxxflags}
%{clang_optflags}
```
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1721553#c34
--
Jun | He - His - Him
4:36 a.m.
* Jun Aruga:
What do you think about adding the following macros in
rpms/redhat-rpm-config?
I think it's useful for people who want to build their RPM package not
by gcc but for some reasons.
rpms/ruby might be the case to build with clang near feature, because
gcc's PIE is not compatible with Ruby's just-in-time (JIT) feature
using pre-compiler-header (PCH) [1].
```
%{build_clang_cflags}
%{build_clang_cxxflags}
%{clang_optflags}
```
I don't think the flag-based approach can be made to work if we support
different system compilers. We will need something else instead. While
the flag names largely overlap, their behavior differs. And due to lack
of compiler specs file support in Clang, the PIE flag handling simply
cannot be implemented in Clang directly, while still having Clang to
default to non-PIE.
I don't know what the current state of Fedora multi-compiler support is.
Has there been a change that allows packages to build with Clang instead
of Clang even if there is no immediate technical requirement to do so?
(If yes, it has not been reflected in the packaging guidelines.)
Thanks,
Florian
5:50 a.m.
Hi Guys,
FYI: I have already opened a pull request to enhance redhat-rpm-config
to allow packages to build with clang instead of gcc if they so wish:
https://src.fedoraproject.org/rpms/redhat-rpm-config/pull-request/82
The patch makes use of clang's CCC_OVERIDE_OPTIONS to process the options
that are normally passed to gcc as well loading clang specific options
from a configuration file. The patch also creates variables called __cc,
__cxx and __cpp which are initialised as might be expected, but which
a package could override to point to some other compiler should it wish
to do so.
Cheers
Nick
1:26 p.m.
On Mon, Apr 06, 2020 at 11:50:53AM +0100, Nick Clifton wrote:
Hi Guys,
FYI: I have already opened a pull request to enhance redhat-rpm-config
to allow packages to build with clang instead of gcc if they so wish:
https://src.fedoraproject.org/rpms/redhat-rpm-config/pull-request/82
The patch makes use of clang's CCC_OVERIDE_OPTIONS to process the options
that are normally passed to gcc as well loading clang specific options
from a configuration file. The patch also creates variables called __cc,
__cxx and __cpp which are initialised as might be expected, but which
a package could override to point to some other compiler should it wish
to do so.
keep in mind https://docs.fedoraproject.org/en-US/packaging-guidelines/#compiler
kevin
3:45 a.m.
> FYI: I have already opened a pull request to enhance
redhat-rpm-config
> to allow packages to build with clang instead of gcc if they so wish:
>
> https://src.fedoraproject.org/rpms/redhat-rpm-config/pull-request/82
The `%define with_cc_clang 1` approach in the PR looks better than the
flag-based approach.
Thanks for work!
We might also need to add the note about %{build_cflags},
%{build_cxxflags} and etc in the guidelines that are written
in https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/buildf...
.
Cheers,
Jun
--
Jun | He - His - Him
3:51 a.m.
* Jun Aruga:
We might also need to add the note about %{build_cflags},
%{build_cxxflags} and etc in the guidelines that are written
in https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/buildf...
.
Please do. It's been more than two years:
<https://pagure.io/packaging-committee/issue/743>
Thanks,
Florian
4:02 a.m.
On Mon, Apr 20, 2020 at 10:51 AM Florian Weimer <fweimer(a)redhat.com> wrote:
* Jun Aruga:
> We might also need to add the note about %{build_cflags},
> %{build_cxxflags} and etc in the guidelines that are written
> in https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/buildf...
> .
Please do. It's been more than two years:
<https://pagure.io/packaging-committee/issue/743>
Note that I included a link to buildflags.md when I rewrote the
RPMMacros page in the Packaging Guidelines a while back:
https://docs.fedoraproject.org/en-US/packaging-guidelines/RPMMacros/#_mac...
The section about compiler flags in the general Packaging Guidelines
seems to be outdated, though:
https://docs.fedoraproject.org/en-US/packaging-guidelines/#_compiler_flags
Without any concrete proposals for changes it's hard for FPC to "just
know" what needs to be done, or how.
If you could open a PR against the Packaging Guidelines for the
changes you want, that would be great.
Thanks,
Fabio
> Thanks,
> Florian
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8 comments
6 participants
participants (6)
-
Fabio Valentini -
Florian Weimer -
Jun Aruga -
Kevin Fenzi -
Neal Gompa -
Nick Clifton