[PATCH] meson.build: Refuse XCode versions < v15.0

[PATCH] meson.build: Refuse XCode versions < v15.0

[Thomas Huth]

According to our support policy, we only support the two latest
major versions of macOS, and we already removed compatibility code
for older versions. However, it's still possible that people install
an older version of XCode on a recent version of macOS - which won't
be able to compile QEMU anymore, see for example the ticket here:

 https://gitlab.com/qemu-project/qemu/-/issues/2694

Thus let's set the expectations right and refuse older versions of
XCode that do not match the two latest versions of macOS anymore.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 meson.build | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/meson.build b/meson.build
index e0b880e4e1..a290dbfa33 100644
--- a/meson.build
+++ b/meson.build
@@ -315,8 +315,8 @@ foreach lang : all_languages
     # ok
   elif compiler.get_id() == 'clang' and compiler.compiles('''
       #ifdef __apple_build_version__
-      # if __clang_major__ < 12 || (__clang_major__ == 12 && __clang_minor__ < 0)
-      #  error You need at least XCode Clang v12.0 to compile QEMU
+      # if __clang_major__ < 15 || (__clang_major__ == 15 && __clang_minor__ < 0)
+      #  error You need at least XCode Clang v15.0 to compile QEMU
       # endif
       #else
       # if __clang_major__ < 10 || (__clang_major__ == 10 && __clang_minor__ < 0)
@@ -325,7 +325,7 @@ foreach lang : all_languages
       #endif''')
     # ok
   else
-    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v12.0) to compile QEMU')
+    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v15.0) to compile QEMU')
   endif
 endforeach
 
-- 
2.47.0

Re: [PATCH] meson.build: Refuse XCode versions < v15.0

[Philippe Mathieu-Daudé]

On 26/11/24 09:10, Thomas Huth wrote:
> According to our support policy, we only support the two latest
> major versions of macOS, and we already removed compatibility code
> for older versions. However, it's still possible that people install
> an older version of XCode on a recent version of macOS - which won't
> be able to compile QEMU anymore, see for example the ticket here:
> 
>   https://gitlab.com/qemu-project/qemu/-/issues/2694

Wondering about this issue, it is possible to install concurrent
XCode versions, which is useful i.e. when you build an application
targeting multiple (and older) App Store releases. See:
https://xcodereleases.com/

Maybe we need to clarify our support policy that we only support
the XCode released with the 2 latest major macOS versions?

> Thus let's set the expectations right and refuse older versions of
> XCode that do not match the two latest versions of macOS anymore.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>   meson.build | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/meson.build b/meson.build
> index e0b880e4e1..a290dbfa33 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -315,8 +315,8 @@ foreach lang : all_languages
>       # ok
>     elif compiler.get_id() == 'clang' and compiler.compiles('''
>         #ifdef __apple_build_version__
> -      # if __clang_major__ < 12 || (__clang_major__ == 12 && __clang_minor__ < 0)
> -      #  error You need at least XCode Clang v12.0 to compile QEMU
> +      # if __clang_major__ < 15 || (__clang_major__ == 15 && __clang_minor__ < 0)
> +      #  error You need at least XCode Clang v15.0 to compile QEMU
>         # endif
>         #else
>         # if __clang_major__ < 10 || (__clang_major__ == 10 && __clang_minor__ < 0)
> @@ -325,7 +325,7 @@ foreach lang : all_languages
>         #endif''')
>       # ok
>     else
> -    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v12.0) to compile QEMU')
> +    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v15.0) to compile QEMU')

BTW apparently CentOS 8 (which we don't support anymore IIRC)
provides Clang 12.0.1, and also Ubuntu 22.04, Alpine 3.16.

I wonder if the relation with XCode __apple_build_version__ is
always __clang_major__ + 3...

>     endif
>   endforeach
>   

Re: [PATCH] meson.build: Refuse XCode versions < v15.0

[Daniel P. Berrangé]

On Tue, Nov 26, 2024 at 09:57:15AM +0100, Philippe Mathieu-Daudé wrote:
> On 26/11/24 09:10, Thomas Huth wrote:
> > According to our support policy, we only support the two latest
> > major versions of macOS, and we already removed compatibility code
> > for older versions. However, it's still possible that people install
> > an older version of XCode on a recent version of macOS - which won't
> > be able to compile QEMU anymore, see for example the ticket here:
> > 
> >   https://gitlab.com/qemu-project/qemu/-/issues/2694
> 
> Wondering about this issue, it is possible to install concurrent
> XCode versions, which is useful i.e. when you build an application
> targeting multiple (and older) App Store releases. See:
> https://xcodereleases.com/

That's true of any platform. You can get many GCC versions for Debian
and Fedora too.

> Maybe we need to clarify our support policy that we only support
> the XCode released with the 2 latest major macOS versions?

We implicitly support the XCode versions that are the "default" with
the latest 2 macOS versions.

> > @@ -315,8 +315,8 @@ foreach lang : all_languages
> >       # ok
> >     elif compiler.get_id() == 'clang' and compiler.compiles('''
> >         #ifdef __apple_build_version__
> > -      # if __clang_major__ < 12 || (__clang_major__ == 12 && __clang_minor__ < 0)
> > -      #  error You need at least XCode Clang v12.0 to compile QEMU
> > +      # if __clang_major__ < 15 || (__clang_major__ == 15 && __clang_minor__ < 0)
> > +      #  error You need at least XCode Clang v15.0 to compile QEMU
> >         # endif
> >         #else
> >         # if __clang_major__ < 10 || (__clang_major__ == 10 && __clang_minor__ < 0)
> > @@ -325,7 +325,7 @@ foreach lang : all_languages
> >         #endif''')
> >       # ok
> >     else
> > -    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v12.0) to compile QEMU')
> > +    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v15.0) to compile QEMU')
> 
> BTW apparently CentOS 8 (which we don't support anymore IIRC)
> provides Clang 12.0.1, and also Ubuntu 22.04, Alpine 3.16.
> 
> I wonder if the relation with XCode __apple_build_version__ is
> always __clang_major__ + 3...

No, it isn't. It varies all over the place -

eg

From xcode 11.3 to 11.4 they bump from llvm 8.0.0 to 9.0.0, while the
clang version goes from 11.0.0 to 11.0.3.

From xcode 15.4 to 16.0 they from llmvm 16.0.0 to 17.0.6, while the
clang version goes from 15.0.0 to 16.0.0.

I can just about interpret a rule they're following, but relating that
to the upstream clang versions algorithmically is impossible.

  https://en.wikipedia.org/wiki/Xcode#Toolchain_versions

With regards,
Daniel
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Re: [PATCH] meson.build: Refuse XCode versions < v15.0

[Philippe Mathieu-Daudé]

On 26/11/24 10:23, Daniel P. Berrangé wrote:
> On Tue, Nov 26, 2024 at 09:57:15AM +0100, Philippe Mathieu-Daudé wrote:
>> On 26/11/24 09:10, Thomas Huth wrote:
>>> According to our support policy, we only support the two latest
>>> major versions of macOS, and we already removed compatibility code
>>> for older versions. However, it's still possible that people install
>>> an older version of XCode on a recent version of macOS - which won't
>>> be able to compile QEMU anymore, see for example the ticket here:
>>>
>>>    https://gitlab.com/qemu-project/qemu/-/issues/2694
>>
>> Wondering about this issue, it is possible to install concurrent
>> XCode versions, which is useful i.e. when you build an application
>> targeting multiple (and older) App Store releases. See:
>> https://xcodereleases.com/
> 
> That's true of any platform. You can get many GCC versions for Debian
> and Fedora too.
> 
>> Maybe we need to clarify our support policy that we only support
>> the XCode released with the 2 latest major macOS versions?
> 
> We implicitly support the XCode versions that are the "default" with
> the latest 2 macOS versions.

Implicit might not be sufficient for users, see #2694.

>>> @@ -315,8 +315,8 @@ foreach lang : all_languages
>>>        # ok
>>>      elif compiler.get_id() == 'clang' and compiler.compiles('''
>>>          #ifdef __apple_build_version__
>>> -      # if __clang_major__ < 12 || (__clang_major__ == 12 && __clang_minor__ < 0)
>>> -      #  error You need at least XCode Clang v12.0 to compile QEMU
>>> +      # if __clang_major__ < 15 || (__clang_major__ == 15 && __clang_minor__ < 0)
>>> +      #  error You need at least XCode Clang v15.0 to compile QEMU
>>>          # endif
>>>          #else
>>>          # if __clang_major__ < 10 || (__clang_major__ == 10 && __clang_minor__ < 0)
>>> @@ -325,7 +325,7 @@ foreach lang : all_languages
>>>          #endif''')
>>>        # ok
>>>      else
>>> -    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v12.0) to compile QEMU')
>>> +    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v15.0) to compile QEMU')
>>
>> BTW apparently CentOS 8 (which we don't support anymore IIRC)
>> provides Clang 12.0.1, and also Ubuntu 22.04, Alpine 3.16.
>>
>> I wonder if the relation with XCode __apple_build_version__ is
>> always __clang_major__ + 3...
> 
> No, it isn't. It varies all over the place -
> 
> eg
> 
>  From xcode 11.3 to 11.4 they bump from llvm 8.0.0 to 9.0.0, while the
> clang version goes from 11.0.0 to 11.0.3.
> 
>  From xcode 15.4 to 16.0 they from llmvm 16.0.0 to 17.0.6, while the
> clang version goes from 15.0.0 to 16.0.0.
> 
> I can just about interpret a rule they're following, but relating that
> to the upstream clang versions algorithmically is impossible.
> 
>    https://en.wikipedia.org/wiki/Xcode#Toolchain_versions

Doh...

Anyway, for this patch:

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Re: [PATCH] meson.build: Refuse XCode versions < v15.0

[Daniel P. Berrangé]

On Tue, Nov 26, 2024 at 12:11:43PM +0100, Philippe Mathieu-Daudé wrote:
> On 26/11/24 10:23, Daniel P. Berrangé wrote:
> > On Tue, Nov 26, 2024 at 09:57:15AM +0100, Philippe Mathieu-Daudé wrote:
> > > On 26/11/24 09:10, Thomas Huth wrote:
> > > > According to our support policy, we only support the two latest
> > > > major versions of macOS, and we already removed compatibility code
> > > > for older versions. However, it's still possible that people install
> > > > an older version of XCode on a recent version of macOS - which won't
> > > > be able to compile QEMU anymore, see for example the ticket here:
> > > > 
> > > >    https://gitlab.com/qemu-project/qemu/-/issues/2694
> > > 
> > > Wondering about this issue, it is possible to install concurrent
> > > XCode versions, which is useful i.e. when you build an application
> > > targeting multiple (and older) App Store releases. See:
> > > https://xcodereleases.com/
> > 
> > That's true of any platform. You can get many GCC versions for Debian
> > and Fedora too.
> > 
> > > Maybe we need to clarify our support policy that we only support
> > > the XCode released with the 2 latest major macOS versions?
> > 
> > We implicitly support the XCode versions that are the "default" with
> > the latest 2 macOS versions.
> 
> Implicit might not be sufficient for users, see #2694.

Well I'm not convinced the persno in that bug report would have
read the docs regardless. 

This patch takes care of making it explicit in a way that can't
be missed though.

> 
> > > > @@ -315,8 +315,8 @@ foreach lang : all_languages
> > > >        # ok
> > > >      elif compiler.get_id() == 'clang' and compiler.compiles('''
> > > >          #ifdef __apple_build_version__
> > > > -      # if __clang_major__ < 12 || (__clang_major__ == 12 && __clang_minor__ < 0)
> > > > -      #  error You need at least XCode Clang v12.0 to compile QEMU
> > > > +      # if __clang_major__ < 15 || (__clang_major__ == 15 && __clang_minor__ < 0)
> > > > +      #  error You need at least XCode Clang v15.0 to compile QEMU
> > > >          # endif
> > > >          #else
> > > >          # if __clang_major__ < 10 || (__clang_major__ == 10 && __clang_minor__ < 0)
> > > > @@ -325,7 +325,7 @@ foreach lang : all_languages
> > > >          #endif''')
> > > >        # ok
> > > >      else
> > > > -    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v12.0) to compile QEMU')
> > > > +    error('You either need GCC v7.4 or Clang v10.0 (or XCode Clang v15.0) to compile QEMU')
> > > 
> > > BTW apparently CentOS 8 (which we don't support anymore IIRC)
> > > provides Clang 12.0.1, and also Ubuntu 22.04, Alpine 3.16.
> > > 
> > > I wonder if the relation with XCode __apple_build_version__ is
> > > always __clang_major__ + 3...
> > 
> > No, it isn't. It varies all over the place -
> > 
> > eg
> > 
> >  From xcode 11.3 to 11.4 they bump from llvm 8.0.0 to 9.0.0, while the
> > clang version goes from 11.0.0 to 11.0.3.
> > 
> >  From xcode 15.4 to 16.0 they from llmvm 16.0.0 to 17.0.6, while the
> > clang version goes from 15.0.0 to 16.0.0.
> > 
> > I can just about interpret a rule they're following, but relating that
> > to the upstream clang versions algorithmically is impossible.
> > 
> >    https://en.wikipedia.org/wiki/Xcode#Toolchain_versions
> 
> Doh...
> 
> Anyway, for this patch:
> 
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> 

With regards,
Daniel
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