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authorLinus Torvalds <torvalds@linux-foundation.org>2018-11-02 04:34:46 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-11-02 04:34:46 +0300
commite468f5c06b5ebef3f6f3c187e51aa6daab667e57 (patch)
treebe59927a66ffdf5dec86154a2ccb4ea51602450e /include/linux/compiler.h
parentbaa888d25ea64d0c59344d474284ca99cfdd449a (diff)
parent1ff2fea5e30ca15752777441ecb64a169fe22e9e (diff)
downloadlinux-e468f5c06b5ebef3f6f3c187e51aa6daab667e57.tar.xz
Merge tag 'compiler-attributes-for-linus-4.20-rc1' of https://github.com/ojeda/linux
Pull compiler attribute updates from Miguel Ojeda: "This 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 a few 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. Finally, the __nonstring variable attribute series has been also applied on top; plus two related patches from Nick Desaulniers for unreachable() that came a bit afterwards" * tag 'compiler-attributes-for-linus-4.20-rc1' of https://github.com/ojeda/linux: compiler-gcc: remove comment about gcc 4.5 from unreachable() compiler.h: update definition of unreachable() Compiler Attributes: ext4: remove local __nonstring definition Compiler Attributes: auxdisplay: panel: use __nonstring Compiler Attributes: enable -Wstringop-truncation on W=1 (gcc >= 8) Compiler Attributes: add support for __nonstring (gcc >= 8) Compiler Attributes: add MAINTAINERS entry Compiler Attributes: add Doc/process/programming-language.rst Compiler Attributes: remove uses of __attribute__ from compiler.h Compiler Attributes: KENTRY used twice the "used" attribute Compiler Attributes: use feature checks instead of version checks Compiler Attributes: add missing SPDX ID in compiler_types.h Compiler Attributes: remove unneeded sparse (__CHECKER__) tests Compiler Attributes: homogenize __must_be_array Compiler Attributes: remove unneeded tests Compiler Attributes: always use the extra-underscores syntax Compiler Attributes: remove unused attributes
Diffstat (limited to 'include/linux/compiler.h')
-rw-r--r--include/linux/compiler.h24
1 files changed, 13 insertions, 11 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 4170fcee5adb..18c80cfa4fc4 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -23,8 +23,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
#define __branch_check__(x, expect, is_constant) ({ \
long ______r; \
static struct ftrace_likely_data \
- __attribute__((__aligned__(4))) \
- __attribute__((section("_ftrace_annotated_branch"))) \
+ __aligned(4) \
+ __section("_ftrace_annotated_branch") \
______f = { \
.data.func = __func__, \
.data.file = __FILE__, \
@@ -59,8 +59,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
({ \
int ______r; \
static struct ftrace_branch_data \
- __attribute__((__aligned__(4))) \
- __attribute__((section("_ftrace_branch"))) \
+ __aligned(4) \
+ __section("_ftrace_branch") \
______f = { \
.func = __func__, \
.file = __FILE__, \
@@ -115,7 +115,10 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
# define ASM_UNREACHABLE
#endif
#ifndef unreachable
-# define unreachable() do { annotate_reachable(); do { } while (1); } while (0)
+# define unreachable() do { \
+ annotate_unreachable(); \
+ __builtin_unreachable(); \
+} while (0)
#endif
/*
@@ -137,7 +140,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
extern typeof(sym) sym; \
static const unsigned long __kentry_##sym \
__used \
- __attribute__((section("___kentry" "+" #sym ), used)) \
+ __section("___kentry" "+" #sym ) \
= (unsigned long)&sym;
#endif
@@ -278,7 +281,7 @@ unsigned long read_word_at_a_time(const void *addr)
* visible to the compiler.
*/
#define __ADDRESSABLE(sym) \
- static void * __attribute__((section(".discard.addressable"), used)) \
+ static void * __section(".discard.addressable") __used \
__PASTE(__addressable_##sym, __LINE__) = (void *)&sym;
/**
@@ -331,10 +334,6 @@ static inline void *offset_to_ptr(const int *off)
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
-#ifndef __optimize
-# define __optimize(level)
-#endif
-
/* Compile time object size, -1 for unknown */
#ifndef __compiletime_object_size
# define __compiletime_object_size(obj) -1
@@ -376,4 +375,7 @@ static inline void *offset_to_ptr(const int *off)
compiletime_assert(__native_word(t), \
"Need native word sized stores/loads for atomicity.")
+/* &a[0] degrades to a pointer: a different type from an array */
+#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
+
#endif /* __LINUX_COMPILER_H */