From 815f0ddb346c196018d4d8f8f55c12b83da1de3f Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Wed, 22 Aug 2018 16:37:24 -0700 Subject: 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 Suggested-by: Eli Friedman Suggested-by: Joe Perches Signed-off-by: Nick Desaulniers Signed-off-by: Linus Torvalds --- include/linux/compiler-intel.h | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) (limited to 'include/linux/compiler-intel.h') diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h index 547cdc920a3c..4c7f9befa9f6 100644 --- a/include/linux/compiler-intel.h +++ b/include/linux/compiler-intel.h @@ -14,10 +14,6 @@ /* Intel ECC compiler doesn't support gcc specific asm stmts. * It uses intrinsics to do the equivalent things. */ -#undef barrier -#undef barrier_data -#undef RELOC_HIDE -#undef OPTIMIZER_HIDE_VAR #define barrier() __memory_barrier() #define barrier_data(ptr) barrier() @@ -38,13 +34,12 @@ #endif -#ifndef __HAVE_BUILTIN_BSWAP16__ /* icc has this, but it's called _bswap16 */ #define __HAVE_BUILTIN_BSWAP16__ #define __builtin_bswap16 _bswap16 -#endif -/* - * icc defines __GNUC__, but does not implement the builtin overflow checkers. +/* 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 clang. */ -#undef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW +#define __visible __attribute__((externally_visible)) -- cgit v1.2.3