I'm working on adding support for __attribute__((__error__(""))) and
__attribute__((__warning__(""))) to Clang. To make use of these in
__compiletime_error and __compiletime_warning (as used by BUILD_BUG and
friends) for newer clang and detect/fallback for older versions of
clang, move these to compiler_attributes.h and guard them with
__has_attribute preprocessor guards.
Link: https://reviews.llvm.org/D106030
Link: https://bugs.llvm.org/show_bug.cgi?id=16428
Link: https://github.com/ClangBuiltLinux/linux/issues/1173
Signed-off-by: Nick Desaulniers <[email protected]>
---
Changes v1 -> v2:
* Use __warning__ rather than warning in __has_attribute check, as per
Nathan.
* Don't sort existing __GCC4_has_attribute_* defines.
include/linux/compiler-gcc.h | 3 ---
include/linux/compiler_attributes.h | 24 ++++++++++++++++++++++++
include/linux/compiler_types.h | 6 ------
3 files changed, 24 insertions(+), 9 deletions(-)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index cb9217fc60af..21c36b69eb06 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -43,9 +43,6 @@
#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
-#define __compiletime_warning(message) __attribute__((__warning__(message)))
-#define __compiletime_error(message) __attribute__((__error__(message)))
-
#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
#define __latent_entropy __attribute__((latent_entropy))
#endif
diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
index 67c5667f8042..fb08b843ab47 100644
--- a/include/linux/compiler_attributes.h
+++ b/include/linux/compiler_attributes.h
@@ -30,6 +30,7 @@
# define __GCC4_has_attribute___assume_aligned__ 1
# define __GCC4_has_attribute___copy__ 0
# define __GCC4_has_attribute___designated_init__ 0
+# define __GCC4_has_attribute___error__ 1
# define __GCC4_has_attribute___externally_visible__ 1
# define __GCC4_has_attribute___no_caller_saved_registers__ 0
# define __GCC4_has_attribute___noclone__ 1
@@ -39,6 +40,7 @@
# define __GCC4_has_attribute___no_sanitize_undefined__ 1
# define __GCC4_has_attribute___no_sanitize_coverage__ 0
# define __GCC4_has_attribute___fallthrough__ 0
+# define __GCC4_has_attribute___warning__ 1
#endif
/*
@@ -138,6 +140,17 @@
# define __designated_init
#endif
+/*
+ * Optional: only supported since clang >= 13.0
+ *
+ * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-error-function-attribute
+ */
+#if __has_attribute(__error__)
+# define __compiletime_error(msg) __attribute__((__error__(msg)))
+#else
+# define __compiletime_error(msg)
+#endif
+
/*
* Optional: not supported by clang
*
@@ -299,6 +312,17 @@
*/
#define __must_check __attribute__((__warn_unused_result__))
+/*
+ * Optional: only supported since clang >= 13.0
+ *
+ * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-warning-function-attribute
+ */
+#if __has_attribute(__warning__)
+# define __compiletime_warning(msg) __attribute__((__warning__(msg)))
+#else
+# define __compiletime_warning(msg)
+#endif
+
/*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index e4ea86fc584d..b6ff83a714ca 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -294,12 +294,6 @@ struct ftrace_likely_data {
#ifndef __compiletime_object_size
# define __compiletime_object_size(obj) -1
#endif
-#ifndef __compiletime_warning
-# define __compiletime_warning(message)
-#endif
-#ifndef __compiletime_error
-# define __compiletime_error(message)
-#endif
#ifdef __OPTIMIZE__
# define __compiletime_assert(condition, msg, prefix, suffix) \
--
2.32.0.554.ge1b32706d8-goog
On 8/2/2021 1:23 PM, 'Nick Desaulniers' via Clang Built Linux wrote:
> I'm working on adding support for __attribute__((__error__(""))) and
> __attribute__((__warning__(""))) to Clang. To make use of these in
> __compiletime_error and __compiletime_warning (as used by BUILD_BUG and
> friends) for newer clang and detect/fallback for older versions of
> clang, move these to compiler_attributes.h and guard them with
> __has_attribute preprocessor guards.
>
> Link: https://reviews.llvm.org/D106030
> Link: https://bugs.llvm.org/show_bug.cgi?id=16428
> Link: https://github.com/ClangBuiltLinux/linux/issues/1173
> Signed-off-by: Nick Desaulniers <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
One comment below, please carry my tag forward in further revisions
unless they are significant.
> ---
> Changes v1 -> v2:
> * Use __warning__ rather than warning in __has_attribute check, as per
> Nathan.
> * Don't sort existing __GCC4_has_attribute_* defines.
>
> include/linux/compiler-gcc.h | 3 ---
> include/linux/compiler_attributes.h | 24 ++++++++++++++++++++++++
> include/linux/compiler_types.h | 6 ------
> 3 files changed, 24 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index cb9217fc60af..21c36b69eb06 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -43,9 +43,6 @@
>
> #define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
>
> -#define __compiletime_warning(message) __attribute__((__warning__(message)))
> -#define __compiletime_error(message) __attribute__((__error__(message)))
> -
> #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
> #define __latent_entropy __attribute__((latent_entropy))
> #endif
> diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
> index 67c5667f8042..fb08b843ab47 100644
> --- a/include/linux/compiler_attributes.h
> +++ b/include/linux/compiler_attributes.h
> @@ -30,6 +30,7 @@
> # define __GCC4_has_attribute___assume_aligned__ 1
> # define __GCC4_has_attribute___copy__ 0
> # define __GCC4_has_attribute___designated_init__ 0
> +# define __GCC4_has_attribute___error__ 1
> # define __GCC4_has_attribute___externally_visible__ 1
> # define __GCC4_has_attribute___no_caller_saved_registers__ 0
> # define __GCC4_has_attribute___noclone__ 1
> @@ -39,6 +40,7 @@
> # define __GCC4_has_attribute___no_sanitize_undefined__ 1
> # define __GCC4_has_attribute___no_sanitize_coverage__ 0
> # define __GCC4_has_attribute___fallthrough__ 0
> +# define __GCC4_has_attribute___warning__ 1
> #endif
>
> /*
> @@ -138,6 +140,17 @@
> # define __designated_init
> #endif
>
> +/*
> + * Optional: only supported since clang >= 13.0
Are you planning on petitioning for D106030 to be applied to
release/13.x when it is merged into main? If not, this should be updated
to 14.0.0 since that is main's current version.
> + *
> + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-error-function-attribute
> + */
> +#if __has_attribute(__error__)
> +# define __compiletime_error(msg) __attribute__((__error__(msg)))
> +#else
> +# define __compiletime_error(msg)
> +#endif
> +
> /*
> * Optional: not supported by clang
> *
> @@ -299,6 +312,17 @@
> */
> #define __must_check __attribute__((__warn_unused_result__))
>
> +/*
> + * Optional: only supported since clang >= 13.0
> + *
> + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-warning-function-attribute
> + */
> +#if __has_attribute(__warning__)
> +# define __compiletime_warning(msg) __attribute__((__warning__(msg)))
> +#else
> +# define __compiletime_warning(msg)
> +#endif
> +
> /*
> * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute
> * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute
> diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> index e4ea86fc584d..b6ff83a714ca 100644
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -294,12 +294,6 @@ struct ftrace_likely_data {
> #ifndef __compiletime_object_size
> # define __compiletime_object_size(obj) -1
> #endif
> -#ifndef __compiletime_warning
> -# define __compiletime_warning(message)
> -#endif
> -#ifndef __compiletime_error
> -# define __compiletime_error(message)
> -#endif
>
> #ifdef __OPTIMIZE__
> # define __compiletime_assert(condition, msg, prefix, suffix) \
>
On Mon, Aug 02, 2021 at 01:23:20PM -0700, Nick Desaulniers wrote:
> I'm working on adding support for __attribute__((__error__(""))) and
> __attribute__((__warning__(""))) to Clang. To make use of these in
> __compiletime_error and __compiletime_warning (as used by BUILD_BUG and
> friends) for newer clang and detect/fallback for older versions of
> clang, move these to compiler_attributes.h and guard them with
> __has_attribute preprocessor guards.
>
> Link: https://reviews.llvm.org/D106030
> Link: https://bugs.llvm.org/show_bug.cgi?id=16428
> Link: https://github.com/ClangBuiltLinux/linux/issues/1173
> Signed-off-by: Nick Desaulniers <[email protected]>
I'm looking forward to having this working in Clang! :)
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
On Mon, Aug 2, 2021 at 1:29 PM Nathan Chancellor <[email protected]> wrote:
>
> On 8/2/2021 1:23 PM, 'Nick Desaulniers' via Clang Built Linux wrote:
> > I'm working on adding support for __attribute__((__error__(""))) and
> > __attribute__((__warning__(""))) to Clang. To make use of these in
> > __compiletime_error and __compiletime_warning (as used by BUILD_BUG and
> > friends) for newer clang and detect/fallback for older versions of
> > clang, move these to compiler_attributes.h and guard them with
> > __has_attribute preprocessor guards.
> >
> > Link: https://reviews.llvm.org/D106030
> > Link: https://bugs.llvm.org/show_bug.cgi?id=16428
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1173
> > Signed-off-by: Nick Desaulniers <[email protected]>
>
> Reviewed-by: Nathan Chancellor <[email protected]>
>
> One comment below, please carry my tag forward in further revisions
> unless they are significant.
>
> > ---
> > Changes v1 -> v2:
> > * Use __warning__ rather than warning in __has_attribute check, as per
> > Nathan.
> > * Don't sort existing __GCC4_has_attribute_* defines.
> >
> > include/linux/compiler-gcc.h | 3 ---
> > include/linux/compiler_attributes.h | 24 ++++++++++++++++++++++++
> > include/linux/compiler_types.h | 6 ------
> > 3 files changed, 24 insertions(+), 9 deletions(-)
> >
> > diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> > index cb9217fc60af..21c36b69eb06 100644
> > --- a/include/linux/compiler-gcc.h
> > +++ b/include/linux/compiler-gcc.h
> > @@ -43,9 +43,6 @@
> >
> > #define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
> >
> > -#define __compiletime_warning(message) __attribute__((__warning__(message)))
> > -#define __compiletime_error(message) __attribute__((__error__(message)))
> > -
> > #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
> > #define __latent_entropy __attribute__((latent_entropy))
> > #endif
> > diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
> > index 67c5667f8042..fb08b843ab47 100644
> > --- a/include/linux/compiler_attributes.h
> > +++ b/include/linux/compiler_attributes.h
> > @@ -30,6 +30,7 @@
> > # define __GCC4_has_attribute___assume_aligned__ 1
> > # define __GCC4_has_attribute___copy__ 0
> > # define __GCC4_has_attribute___designated_init__ 0
> > +# define __GCC4_has_attribute___error__ 1
> > # define __GCC4_has_attribute___externally_visible__ 1
> > # define __GCC4_has_attribute___no_caller_saved_registers__ 0
> > # define __GCC4_has_attribute___noclone__ 1
> > @@ -39,6 +40,7 @@
> > # define __GCC4_has_attribute___no_sanitize_undefined__ 1
> > # define __GCC4_has_attribute___no_sanitize_coverage__ 0
> > # define __GCC4_has_attribute___fallthrough__ 0
> > +# define __GCC4_has_attribute___warning__ 1
> > #endif
> >
> > /*
> > @@ -138,6 +140,17 @@
> > # define __designated_init
> > #endif
> >
> > +/*
> > + * Optional: only supported since clang >= 13.0
>
> Are you planning on petitioning for D106030 to be applied to
> release/13.x when it is merged into main? If not, this should be updated
> to 14.0.0 since that is main's current version.
Ah, I forgot the release/13.x branch was cut before I sent this. I'd
rather this feature "ride the trains" so that it gets more soak time.
Miguel, would you like a v3 updating the comment above (and the
comment below) to s/13.0/14.0/g, or can you simply fold that change
into this one when applying it?
>
> > + *
> > + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-error-function-attribute
> > + */
> > +#if __has_attribute(__error__)
> > +# define __compiletime_error(msg) __attribute__((__error__(msg)))
> > +#else
> > +# define __compiletime_error(msg)
> > +#endif
> > +
> > /*
> > * Optional: not supported by clang
> > *
> > @@ -299,6 +312,17 @@
> > */
> > #define __must_check __attribute__((__warn_unused_result__))
> >
> > +/*
> > + * Optional: only supported since clang >= 13.0
> > + *
> > + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-warning-function-attribute
> > + */
> > +#if __has_attribute(__warning__)
> > +# define __compiletime_warning(msg) __attribute__((__warning__(msg)))
> > +#else
> > +# define __compiletime_warning(msg)
> > +#endif
> > +
> > /*
> > * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute
> > * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute
> > diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> > index e4ea86fc584d..b6ff83a714ca 100644
> > --- a/include/linux/compiler_types.h
> > +++ b/include/linux/compiler_types.h
> > @@ -294,12 +294,6 @@ struct ftrace_likely_data {
> > #ifndef __compiletime_object_size
> > # define __compiletime_object_size(obj) -1
> > #endif
> > -#ifndef __compiletime_warning
> > -# define __compiletime_warning(message)
> > -#endif
> > -#ifndef __compiletime_error
> > -# define __compiletime_error(message)
> > -#endif
> >
> > #ifdef __OPTIMIZE__
> > # define __compiletime_assert(condition, msg, prefix, suffix) \
> >
--
Thanks,
~Nick Desaulniers
On Wed, Aug 4, 2021 at 7:44 PM Nick Desaulniers <[email protected]> wrote:
>
> Ah, I forgot the release/13.x branch was cut before I sent this. I'd
> rather this feature "ride the trains" so that it gets more soak time.
>
> Miguel, would you like a v3 updating the comment above (and the
> comment below) to s/13.0/14.0/g, or can you simply fold that change
> into this one when applying it?
I can do the replacements on my side, no worries!
Cheers,
Miguel
On Wed, Aug 4, 2021 at 10:49 AM Miguel Ojeda
<[email protected]> wrote:
>
> On Wed, Aug 4, 2021 at 7:44 PM Nick Desaulniers <[email protected]> wrote:
> >
> > Ah, I forgot the release/13.x branch was cut before I sent this. I'd
> > rather this feature "ride the trains" so that it gets more soak time.
> >
> > Miguel, would you like a v3 updating the comment above (and the
> > comment below) to s/13.0/14.0/g, or can you simply fold that change
> > into this one when applying it?
>
> I can do the replacements on my side, no worries!
Bump, this has landed in llvm 14 (so needs a fixup when applying locally).
--
Thanks,
~Nick Desaulniers