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* [PATCH bpf-next v4 6/8] compiler_types.h: Add unified __diag_ignore_all for GCC/LLVM
       [not found] <20220304224645.3677453-1-memxor@gmail.com>
@ 2022-03-04 22:46 ` Kumar Kartikeya Dwivedi
  2022-03-07 19:30   ` Nick Desaulniers
  0 siblings, 1 reply; 3+ messages in thread
From: Kumar Kartikeya Dwivedi @ 2022-03-04 22:46 UTC (permalink / raw)
  To: bpf
  Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
	Martin KaFai Lau, linux-kernel

Add a __diag_ignore_all macro, to ignore warnings for both GCC and LLVM,
without having to specify the compiler type and version. By default, GCC
8 and clang 11 are used. This will be used by bpf subsystem to ignore
-Wmissing-prototypes warning for functions that are meant to be global
functions so that they are in vmlinux BTF, but don't have a prototype.

Cc: linux-kernel@vger.kernel.org
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 include/linux/compiler-clang.h | 3 +++
 include/linux/compiler-gcc.h   | 3 +++
 include/linux/compiler_types.h | 4 ++++
 3 files changed, 10 insertions(+)

diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index f1aa41d520bd..babb1347148c 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -90,3 +90,6 @@
 #else
 #define __diag_clang_11(s)
 #endif
+
+#define __diag_ignore_all(option, comment) \
+	__diag_clang(11, ignore, option)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index ccbbd31b3aae..d364c98a4a80 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -151,6 +151,9 @@
 #define __diag_GCC_8(s)
 #endif
 
+#define __diag_ignore_all(option, comment) \
+	__diag_GCC(8, ignore, option)
+
 /*
  * Prior to 9.1, -Wno-alloc-size-larger-than (and therefore the "alloc_size"
  * attribute) do not work, and must be disabled.
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 3f31ff400432..8e5d2f50f951 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -371,4 +371,8 @@ struct ftrace_likely_data {
 #define __diag_error(compiler, version, option, comment) \
 	__diag_ ## compiler(version, error, option)
 
+#ifndef __diag_ignore_all
+#define __diag_ignore_all(option, comment)
+#endif
+
 #endif /* __LINUX_COMPILER_TYPES_H */
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH bpf-next v4 6/8] compiler_types.h: Add unified __diag_ignore_all for GCC/LLVM
  2022-03-04 22:46 ` [PATCH bpf-next v4 6/8] compiler_types.h: Add unified __diag_ignore_all for GCC/LLVM Kumar Kartikeya Dwivedi
@ 2022-03-07 19:30   ` Nick Desaulniers
  2022-03-07 20:51     ` Kumar Kartikeya Dwivedi
  0 siblings, 1 reply; 3+ messages in thread
From: Nick Desaulniers @ 2022-03-07 19:30 UTC (permalink / raw)
  To: Kumar Kartikeya Dwivedi
  Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
	Martin KaFai Lau, linux-kernel

On Sat, Mar 05, 2022 at 04:16:43AM +0530, Kumar Kartikeya Dwivedi wrote:
> Add a __diag_ignore_all macro, to ignore warnings for both GCC and LLVM,
> without having to specify the compiler type and version. By default, GCC
> 8 and clang 11 are used. This will be used by bpf subsystem to ignore
> -Wmissing-prototypes warning for functions that are meant to be global
> functions so that they are in vmlinux BTF, but don't have a prototype.
> 
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> ---
>  include/linux/compiler-clang.h | 3 +++
>  include/linux/compiler-gcc.h   | 3 +++
>  include/linux/compiler_types.h | 4 ++++
>  3 files changed, 10 insertions(+)
> 
> diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> index f1aa41d520bd..babb1347148c 100644
> --- a/include/linux/compiler-clang.h
> +++ b/include/linux/compiler-clang.h
> @@ -90,3 +90,6 @@
>  #else
>  #define __diag_clang_11(s)
>  #endif
> +
> +#define __diag_ignore_all(option, comment) \
> +	__diag_clang(11, ignore, option)
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index ccbbd31b3aae..d364c98a4a80 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -151,6 +151,9 @@
>  #define __diag_GCC_8(s)
>  #endif
>  
> +#define __diag_ignore_all(option, comment) \
> +	__diag_GCC(8, ignore, option)

While this approach will work for clang, it doesn't seem scalable for
GCC. Documentation/process/changes.rst documents that we support gcc
5.1+. This approach will only disable diagnostics for gcc 8+.

> +
>  /*
>   * Prior to 9.1, -Wno-alloc-size-larger-than (and therefore the "alloc_size"
>   * attribute) do not work, and must be disabled.
> diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> index 3f31ff400432..8e5d2f50f951 100644
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -371,4 +371,8 @@ struct ftrace_likely_data {
>  #define __diag_error(compiler, version, option, comment) \
>  	__diag_ ## compiler(version, error, option)
>  
> +#ifndef __diag_ignore_all
> +#define __diag_ignore_all(option, comment)
> +#endif
> +
>  #endif /* __LINUX_COMPILER_TYPES_H */
> -- 
> 2.35.1
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH bpf-next v4 6/8] compiler_types.h: Add unified __diag_ignore_all for GCC/LLVM
  2022-03-07 19:30   ` Nick Desaulniers
@ 2022-03-07 20:51     ` Kumar Kartikeya Dwivedi
  0 siblings, 0 replies; 3+ messages in thread
From: Kumar Kartikeya Dwivedi @ 2022-03-07 20:51 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
	Martin KaFai Lau, linux-kernel

On Tue, Mar 08, 2022 at 01:00:18AM IST, Nick Desaulniers wrote:
> On Sat, Mar 05, 2022 at 04:16:43AM +0530, Kumar Kartikeya Dwivedi wrote:
> > Add a __diag_ignore_all macro, to ignore warnings for both GCC and LLVM,
> > without having to specify the compiler type and version. By default, GCC
> > 8 and clang 11 are used. This will be used by bpf subsystem to ignore
> > -Wmissing-prototypes warning for functions that are meant to be global
> > functions so that they are in vmlinux BTF, but don't have a prototype.
> >
> > Cc: linux-kernel@vger.kernel.org
> > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> > ---
> >  include/linux/compiler-clang.h | 3 +++
> >  include/linux/compiler-gcc.h   | 3 +++
> >  include/linux/compiler_types.h | 4 ++++
> >  3 files changed, 10 insertions(+)
> >
> > diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> > index f1aa41d520bd..babb1347148c 100644
> > --- a/include/linux/compiler-clang.h
> > +++ b/include/linux/compiler-clang.h
> > @@ -90,3 +90,6 @@
> >  #else
> >  #define __diag_clang_11(s)
> >  #endif
> > +
> > +#define __diag_ignore_all(option, comment) \
> > +	__diag_clang(11, ignore, option)
> > diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> > index ccbbd31b3aae..d364c98a4a80 100644
> > --- a/include/linux/compiler-gcc.h
> > +++ b/include/linux/compiler-gcc.h
> > @@ -151,6 +151,9 @@
> >  #define __diag_GCC_8(s)
> >  #endif
> >
> > +#define __diag_ignore_all(option, comment) \
> > +	__diag_GCC(8, ignore, option)
>
> While this approach will work for clang, it doesn't seem scalable for
> GCC. Documentation/process/changes.rst documents that we support gcc
> 5.1+. This approach will only disable diagnostics for gcc 8+.
>

ISTM the original commit adding these macros only defined them for GCC 8+, so
coverage for previous versions is already not there, unrelated to this change.
I am not sure what the reason for that was, though.

> > +
> >  /*
> >   * Prior to 9.1, -Wno-alloc-size-larger-than (and therefore the "alloc_size"
> >   * attribute) do not work, and must be disabled.
> > diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> > index 3f31ff400432..8e5d2f50f951 100644
> > --- a/include/linux/compiler_types.h
> > +++ b/include/linux/compiler_types.h
> > @@ -371,4 +371,8 @@ struct ftrace_likely_data {
> >  #define __diag_error(compiler, version, option, comment) \
> >  	__diag_ ## compiler(version, error, option)
> >
> > +#ifndef __diag_ignore_all
> > +#define __diag_ignore_all(option, comment)
> > +#endif
> > +
> >  #endif /* __LINUX_COMPILER_TYPES_H */
> > --
> > 2.35.1
> >

--
Kartikeya

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2022-03-07 20:52 UTC | newest]

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     [not found] <20220304224645.3677453-1-memxor@gmail.com>
2022-03-04 22:46 ` [PATCH bpf-next v4 6/8] compiler_types.h: Add unified __diag_ignore_all for GCC/LLVM Kumar Kartikeya Dwivedi
2022-03-07 19:30   ` Nick Desaulniers
2022-03-07 20:51     ` Kumar Kartikeya Dwivedi

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