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 <[email protected]>
Suggested-by: Eli Friedman <[email protected]>
Suggested-by: Joe Perches <[email protected]>
Signed-off-by: Nick Desaulniers <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Nick Desaulniers 2018-08-22 16:37:24 -07:00 • committed by Linus Torvalds
commit 815f0ddb34
9 changed files with 133 additions and 253 deletions

View file

@ -652,9 +652,9 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node)
* list_head to stay clear from the rb_parent_color union
* (aligned and different than any node) and also different
* from &migrate_nodes. This will verify that future list.h changes
* don't break STABLE_NODE_DUP_HEAD.
* don't break STABLE_NODE_DUP_HEAD. Only recent gcc can handle it.
*/
#if GCC_VERSION >= 40903 /* only recent gcc can handle it */
#if defined(GCC_VERSION) && GCC_VERSION >= 40903
BUILD_BUG_ON(STABLE_NODE_DUP_HEAD <= &migrate_nodes);
BUILD_BUG_ON(STABLE_NODE_DUP_HEAD >= &migrate_nodes + 1);
#endif

View file

@ -1131,7 +1131,8 @@ out:
* gcc 4.7 and 4.8 on arm get an ICEs when inlining unmap_and_move(). Work
* around it.
*/
#if (GCC_VERSION >= 40700 && GCC_VERSION < 40900) && defined(CONFIG_ARM)
#if defined(CONFIG_ARM) && \
defined(GCC_VERSION) && GCC_VERSION < 40900 && GCC_VERSION >= 40700
#define ICE_noinline noinline
#else
#define ICE_noinline