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authorNick Desaulniers <ndesaulniers@google.com>2018-08-23 02:37:24 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-23 03:31:34 +0300
commit815f0ddb346c196018d4d8f8f55c12b83da1de3f (patch)
tree4805bf7e3cb7ec4e727aba8e62f9211e9001a760 /include/linux/compiler-clang.h
parent899fbc33fd775b9dfa363db28f322272920a2196 (diff)
downloadlinux-815f0ddb346c196018d4d8f8f55c12b83da1de3f.tar.xz
include/linux/compiler*.h: make compiler-*.h mutually exclusive
Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6") recently exposed a brittle part of the build for supporting non-gcc compilers. Both Clang and ICC define __GNUC__, __GNUC_MINOR__, and __GNUC_PATCHLEVEL__ for quick compatibility with code bases that haven't added compiler specific checks for __clang__ or __INTEL_COMPILER. This is brittle, as they happened to get compatibility by posing as a certain version of GCC. This broke when upgrading the minimal version of GCC required to build the kernel, to a version above what ICC and Clang claim to be. Rather than always including compiler-gcc.h then undefining or redefining macros in compiler-intel.h or compiler-clang.h, let's separate out the compiler specific macro definitions into mutually exclusive headers, do more proper compiler detection, and keep shared definitions in compiler_types.h. Fixes: cafa0010cd51 ("Raise the minimum required gcc version to 4.6") Reported-by: Masahiro Yamada <yamada.masahiro@socionext.com> Suggested-by: Eli Friedman <efriedma@codeaurora.org> Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/compiler-clang.h')
-rw-r--r--include/linux/compiler-clang.h20
1 files changed, 9 insertions, 11 deletions
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index 7087446c24c8..b1ce500fe8b3 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -6,11 +6,7 @@
/* Some compiler specific definitions are overwritten here
* for Clang compiler
*/
-
-#ifdef uninitialized_var
-#undef uninitialized_var
#define uninitialized_var(x) x = *(&(x))
-#endif
/* same as gcc, this was present in clang-2.6 so we can assume it works
* with any version that can compile the kernel
@@ -25,14 +21,8 @@
#define __SANITIZE_ADDRESS__
#endif
-#undef __no_sanitize_address
#define __no_sanitize_address __attribute__((no_sanitize("address")))
-/* Clang doesn't have a way to turn it off per-function, yet. */
-#ifdef __noretpoline
-#undef __noretpoline
-#endif
-
/*
* Not all versions of clang implement the the type-generic versions
* of the builtin overflow checkers. Fortunately, clang implements
@@ -40,9 +30,17 @@
* checks. Unfortunately, we don't know which version of gcc clang
* pretends to be, so the macro may or may not be defined.
*/
-#undef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW
#if __has_builtin(__builtin_mul_overflow) && \
__has_builtin(__builtin_add_overflow) && \
__has_builtin(__builtin_sub_overflow)
#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
#endif
+
+/* The following are for compatibility with GCC, from compiler-gcc.h,
+ * and may be redefined here because they should not be shared with other
+ * compilers, like ICC.
+ */
+#define barrier() __asm__ __volatile__("" : : : "memory")
+#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
+#define __assume_aligned(a, ...) \
+ __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))