linux-stable/include/linux/compiler-intel.h
Nick Desaulniers 815f0ddb34 include/linux/compiler*.h: make compiler-*.h mutually exclusive
Commit cafa0010cd ("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: cafa0010cd ("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>
2018-08-22 17:31:34 -07:00

45 lines
1.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_COMPILER_TYPES_H
#error "Please don't include <linux/compiler-intel.h> directly, include <linux/compiler.h> instead."
#endif
#ifdef __ECC
/* Some compiler specific definitions are overwritten here
* for Intel ECC compiler
*/
#include <asm/intrinsics.h>
/* Intel ECC compiler doesn't support gcc specific asm stmts.
* It uses intrinsics to do the equivalent things.
*/
#define barrier() __memory_barrier()
#define barrier_data(ptr) barrier()
#define RELOC_HIDE(ptr, off) \
({ unsigned long __ptr; \
__ptr = (unsigned long) (ptr); \
(typeof(ptr)) (__ptr + (off)); })
/* This should act as an optimization barrier on var.
* Given that this compiler does not have inline assembly, a compiler barrier
* is the best we can do.
*/
#define OPTIMIZER_HIDE_VAR(var) barrier()
/* Intel ECC compiler doesn't support __builtin_types_compatible_p() */
#define __must_be_array(a) 0
#endif
/* icc has this, but it's called _bswap16 */
#define __HAVE_BUILTIN_BSWAP16__
#define __builtin_bswap16 _bswap16
/* 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.
*/
#define __visible __attribute__((externally_visible))