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Subject[PATCH v3 00/12] Compiler Attributes
The Compiler Attributes series is an effort to disentangle
the include/linux/compiler*.h headers and bring them up to date.

The main idea behind the series is to use feature checking macros
(i.e. __has_attribute) instead of compiler version checks (e.g. GCC_VERSION),
which are compiler-agnostic (so they can be shared, reducing the size
of compiler-specific headers) and version-agnostic.

Other related improvements have been performed in the headers as well,
which on top of the use of __has_attribute it has amounted to a significant
simplification of these headers (e.g. GCC_VERSION is now only guarding 4
non-attribute macros).

This series should also help the efforts to support compiling the kernel
with clang and icc. A fair amount of documentation and comments have also
been added, clarified or removed; and the headers are now more readable,
which should help kernel developers in general.

The series was triggered due to the move to gcc >= 4.6. In turn, this series
has also triggered Sparse to gain the ability to recognize __has_attribute
on its own.

You can also fetch it from:



Cc: Jonathan Corbet <>
Cc: Rasmus Villemoes <>
Cc: Luc Van Oostenryck <>
Cc: Eli Friedman <>
Cc: Christopher Li <>
Cc: Kees Cook <>
Cc: Ingo Molnar <>
Cc: Geert Uytterhoeven <>
Cc: Arnd Bergmann <>
Cc: Greg Kroah-Hartman <>
Cc: Masahiro Yamada <>
Cc: Joe Perches <>
Cc: Dominique Martinet <>
Cc: Nick Desaulniers <>
Cc: Linus Torvalds <>
Signed-off-by: Miguel Ojeda <>

v2 -> v3:


* Remove duplicated "used" attribute in KENTRY
* Silence sparse warnings on __has_attribute & simplify the macro block
* Add Documentation/process/programming-language.rst
* Improve _attribute.h description
* Improve some commit descriptions
* Add Reviewed-by's/Acked-by's/Suggested-by's
(hopefully I didn't miss anybody!)
* Rebase on top of v4.19-rc2
* Cc Rasmus, Luc

From reviews:

* Fix __attribute_const__ rename typo (Nick)
* Add SPDX identifier to _attributes.h (Nick)
* Add SPDX identifier to _types.h (Greg)
* Remove __attribute__ uses from compiler.h (Nick)
* Tweak clang doc comments (Nick)
* Move __naked out of -gcc.h to be shared (Arnd)
* Use __name__ syntax instead (Rasmus)
* Update sparse description (Luc)
* Remove __CHECKER__ test from __must_be_array (Luc)
* Add note on __has_attribute regarding sparse (Luc)
* Cc linux-sparse (Luc)

It is quite a lot of stuff changed this time around, I hope I haven't missed
anything said in the emails. Please take a look!

Compile-tested for a while on (x86_64, gcc-7.3, allmodconfig).

Miguel Ojeda (12):
Compiler Attributes: remove unused attributes
Compiler Attributes: always use the extra-underscores syntax
Compiler Attributes: remove unneeded tests
Compiler Attributes: homogenize __must_be_array
Compiler Attributes: naked was fixed in gcc 4.6
Compiler Attributes: naked can be shared
Compiler Attributes: remove unneeded sparse (__CHECKER__) tests
Compiler Attributes: add missing SPDX ID in compiler_types.h
Compiler Attributes: use feature checks instead of version checks
Compiler Attributes: KENTRY used twice the "used" attribute
Compiler Attributes: remove uses of __attribute__ from compiler.h
Compiler Attributes: add Doc/process/programming-language.rst

Documentation/process/index.rst | 1 +
.../process/programming-language.rst | 44 ++++
include/linux/compiler-clang.h | 5 -
include/linux/compiler-gcc.h | 84 +-----
include/linux/compiler-intel.h | 9 -
include/linux/compiler.h | 19 +-
include/linux/compiler_attributes.h | 239 ++++++++++++++++++
include/linux/compiler_types.h | 101 ++------
8 files changed, 314 insertions(+), 188 deletions(-)
create mode 100644 Documentation/process/programming-language.rst
create mode 100644 include/linux/compiler_attributes.h


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