From: Nick Desaulniers <ndesaulniers@google.com>
To: Miguel Ojeda <ojeda@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
Nathan Chancellor <nathan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Kees Cook <keescook@chromium.org>, Marco Elver <elver@google.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
Will Deacon <will@kernel.org>,
Sami Tolvanen <samitolvanen@google.com>,
Arnd Bergmann <arnd@arndb.de>, Ard Biesheuvel <ardb@kernel.org>,
linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: [PATCH v2] compiler_attributes.h: move __compiletime_{error|warning}
Date: Mon, 2 Aug 2021 13:23:20 -0700 [thread overview]
Message-ID: <20210802202326.1817503-1-ndesaulniers@google.com> (raw)
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 <ndesaulniers@google.com>
---
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
next reply other threads:[~2021-08-02 20:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-02 20:23 Nick Desaulniers [this message]
2021-08-02 20:29 ` [PATCH v2] compiler_attributes.h: move __compiletime_{error|warning} Nathan Chancellor
2021-08-04 17:43 ` Nick Desaulniers
2021-08-04 17:48 ` Miguel Ojeda
2021-09-02 18:26 ` Nick Desaulniers
2021-08-03 6:42 ` Kees Cook
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