What is the best practice to use both gcc and clang flags macros in %check?

[Jun Aruga]

In my case on rpms/simde, I want to compile the testing source in
"both" gcc and clang changing the toolchain macro in the %check
section.

I am seeing this file to use toolchain macro.
https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/macros#_4...
> # %global toolchain clang

In this case what is the best practice to use %{optflags},
%{build_cflags}, %{build_cxxflags} macros?
Because after setting `%global toolchain clang` in the %check section,
these macros are empty.

Here is the simde.spec having both gcc and clang built test cases in
the%check section.
https://src.fedoraproject.org/fork/jaruga/rpms/simde/blob/wip/clang-flto-ftb...

```
%check
...
echo "=== 1.2. tests on gcc with flags ==="
mkdir test/build-gcc-with-flags
pushd test/build-gcc-with-flags
CC=gcc CXX=g++ cmake \
  -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON \
  -DCMAKE_C_FLAGS="%{build_cflags}" \
  -DCMAKE_CXX_FLAGS="%{build_cxxflags}" \
  ..
...
%global toolchain clang
...
echo "=== 2.2. tests on clang with flags ==="
mkdir test/build-clang-with-flags
pushd test/build-clang-with-flags
CC=clang CXX=clang++ cmake \
  -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON \
  -DCMAKE_C_FLAGS="${build_cflags}" \ # <= ${build_cflags} is empty!
  -DCMAKE_CXX_FLAGS="${build_cxxflags}" \ # <= ${build_cxxflags} is empty!
  ..
```

The scratch build: https://koji.fedoraproject.org/koji/taskinfo?taskID=48755502

Thanks.

[Jun Aruga]

As a reference, the following case works as expected on Fedora rawhide.

```
<mock-chroot> sh-5.0# rpm -q rpm
rpm-4.16.0-0.beta3.2.fc33.3.x86_64

<mock-chroot> sh-5.0# rpm -q redhat-rpm-config
redhat-rpm-config-166-1.fc33.noarch

<mock-chroot> sh-5.0# rpm --define 'toolchain gcc' --eval '%{optflags}'
-O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches
-pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
-Wp,-D_GLIBCXX_ASSERTIONS
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
-fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1
 -m64 -mtune=generic -fasynchronous-unwind-tables
-fstack-clash-protection -fcf-protection

<mock-chroot> sh-5.0# rpm --define 'toolchain clang' --eval '%{optflags}'
-O2 -flto -fexceptions -g -grecord-gcc-switches -pipe -Wall
-Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
-Wp,-D_GLIBCXX_ASSERTIONS --config
/usr/lib/rpm/redhat/redhat-hardened-clang.cfg -fstack-protector-strong
  -m64 -mtune=generic -fasynchronous-unwind-tables  -fcf-protection
```

[Fabio Valentini]

On Wed, Aug 5, 2020 at 7:36 PM Jun Aruga  wrote:
> In my case on rpms/simde, I want to compile the testing source in
> "both" gcc and clang changing the toolchain macro in the %check
> section.
>
> I am seeing this file to use toolchain macro.
> https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/macros#_4...
> > # %global toolchain clang
>
> In this case what is the best practice to use %{optflags},
> %{build_cflags}, %{build_cxxflags} macros?
> Because after setting `%global toolchain clang` in the %check section,
> these macros are empty.
>
> Here is the simde.spec having both gcc and clang built test cases in
> the%check section.
> https://src.fedoraproject.org/fork/jaruga/rpms/simde/blob/wip/clang-flto-ftb...
> %check
> ...
> echo "=== 1.2. tests on gcc with flags ==="
> mkdir test/build-gcc-with-flags
> pushd test/build-gcc-with-flags
> CC=gcc CXX=g++ cmake \
>   -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON \
>   -DCMAKE_C_FLAGS="%{build_cflags}" \
>   -DCMAKE_CXX_FLAGS="%{build_cxxflags}" \
>   ..
> ...
> %global toolchain clang
> ...
> echo "=== 2.2. tests on clang with flags ==="
> mkdir test/build-clang-with-flags
> pushd test/build-clang-with-flags
> CC=clang CXX=clang++ cmake \
>   -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON \
>   -DCMAKE_C_FLAGS="${build_cflags}" \ # <= ${build_cflags} is empty!
>   -DCMAKE_CXX_FLAGS="${build_cxxflags}" \ # <= ${build_cxxflags} is empty!
>   ..

I see no way this can actually work.

For one, there's typos in the second part ($ instead of %, which of
course makes them empty when those environment variables aren't
defined).

Also I don't think you can set RPM .spec macros *within* a %check
script (which is executed by bash), so `%global toolchain clang` would
get passed to bash in this case, instead of getting parsed by RPM, no?
So the errors after this line are understandable to me.

I also wonder why you are trying to override `toolchain` manually in
this case, which I don't think is necessary at all. Reading the docs
for those macros, it looks like using %set_build_flags and setting CC
and CXX correctly should do what you want to do (unless CMake doesn't
read those environment variables correctly, then you need to use
%build_cflags, %build_cxxflags, %build_ldflags as you did before).

Fabio

[Jun Aruga]

> I see no way this can actually work.
>
> For one, there's typos in the second part ($ instead of %, which of
> course makes them empty when those environment variables aren't
> defined).

Ahh, sorry for my mistakes. Thank you for finding my mistakes.
> Also I don't think you can set RPM .spec macros *within* a %check
> script (which is executed by bash), so `%global toolchain clang` would
> get passed to bash in this case, instead of getting parsed by RPM, no?
> So the errors after this line are understandable to me.

After fixing the typos, then the lines after setting `%global
toolchain clang` in %check section, it seems that the macros are used
as clang values.

The scratch build: https://koji.fedoraproject.org/koji/taskinfo?taskID=48762229

```
+ CC=clang
+ CXX=clang++
+ cmake -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON '-DCMAKE_C_FLAGS=-O2 -flto
-fexceptions -g -grecord-gcc-switches -pipe -Wall
-Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
-Wp,-D_GLIBCXX_ASSERTIONS --config
/usr/lib/rpm/redhat/redhat-hardened-clang.cfg -fstack-protector-strong
  -m64 -mtune=generic -fasynchronous-unwind-tables  -fcf-protection'
'-DCMAKE_CXX_FLAGS=-O2 -flto -fexceptions -g -grecord-gcc-switches
-pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
-Wp,-D_GLIBCXX_ASSERTIONS --config
/usr/lib/rpm/redhat/redhat-hardened-clang.cfg -fstack-protector-strong
  -m64 -mtune=generic -fasynchronous-unwind-tables  -fcf-protection'
..
```
> I also wonder why you are trying to override `toolchain` manually in
> this case, which I don't think is necessary at all. Reading the docs
> for those macros, it looks like using %set_build_flags and setting CC
> and CXX correctly should do what you want to do (unless CMake doesn't
> read those environment variables correctly, then you need to use
> %build_cflags, %build_cxxflags, %build_ldflags as you did before).

Let me check how to use %set_build_flags with CC=clang CXX=clang++.

Thanks!

[Jun Aruga]

> Let me check how to use %set_build_flags with CC=clang CXX=clang++.

Maybe my intent using the cmake options -DCMAKE_C_FLAGS
-DCMAKE_CXX_FLAGS was I wanted to align with the usage in the upstream
[1].
I have a resistance to use %set_build_flags in this case, as it has
the exported environment variables [2] with the wider scope in %check
where I want to run 4 test cases changing the environment variables
for each test case.

Though I still do not know how to use %set_build_flags for clang, I
can go ahead with the current spec file.

[1] https://github.com/simd-everywhere/simde/blob/0f4bc1a2e0ee28e8eeea9a5c5de9c4...
[2] https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/macros#_9...

[Fabio Valentini]

On Wed, Aug 5, 2020 at 9:36 PM Jun Aruga  wrote:
> > Let me check how to use %set_build_flags with CC=clang CXX=clang++.
>
> Maybe my intent using the cmake options -DCMAKE_C_FLAGS
> -DCMAKE_CXX_FLAGS was I wanted to align with the usage in the upstream
> [1].
> I have a resistance to use %set_build_flags in this case, as it has
> the exported environment variables [2] with the wider scope in %check
> where I want to run 4 test cases changing the environment variables
> for each test case.

If you want to make things more complicated, you can always use subshells :)
> Though I still do not know how to use %set_build_flags for clang, I
> can go ahead with the current spec file.
>
> [1] https://github.com/simd-everywhere/simde/blob/0f4bc1a2e0ee28e8eeea9a5c5de9c4...
> [2] https://src.fedoraproject.org/rpms/redhat-rpm-config/blob/master/f/macros#_9...
>
> --
> Jun | He - His - Him
> _______________________________________________
> packaging mailing list -- [e-mail]
> To unsubscribe send an email to [e-mail]
> Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/
> List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
> List Archives: https://lists.fedoraproject.org/archives/list/[e-mail]....