compiler-gcc: integrate the various compiler-gcc[345].h files

commit cb984d101b30eb7478d32df56a0023e4603cba7f upstream.

As gcc major version numbers are going to advance rather rapidly in the
future, there's no real value in separate files for each compiler
version.

Deduplicate some of the macros #defined in each file too.

Neaten comments using normal kernel commenting style.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Alan Modra <amodra@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ philm: backport to 3.10-stable ]
Signed-off-by: Philip Müller <philm@manjaro.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

(cherry picked from commit a4a4f1cd733fe5b345db4e8cc19bb8868d562a8a)

4 files changed, 110 insertions, 181 deletions

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 24545cd90a25..36402e27b016 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -97,10 +97,116 @@
 #define __maybe_unused			__attribute__((unused))
 #define __always_unused			__attribute__((unused))
 
-#define __gcc_header(x) #x
-#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
-#define gcc_header(x) _gcc_header(x)
-#include gcc_header(__GNUC__)
+/* gcc version specific checks */
+
+#if GCC_VERSION < 30200
+# error Sorry, your compiler is too old - please upgrade it.
+#endif
+
+#if GCC_VERSION < 30300
+# define __used			__attribute__((__unused__))
+#else
+# define __used			__attribute__((__used__))
+#endif
+
+#ifdef CONFIG_GCOV_KERNEL
+# if GCC_VERSION < 30400
+#   error "GCOV profiling support for gcc versions below 3.4 not included"
+# endif /* __GNUC_MINOR__ */
+#endif /* CONFIG_GCOV_KERNEL */
+
+#if GCC_VERSION >= 30400
+#define __must_check		__attribute__((warn_unused_result))
+#endif
+
+#if GCC_VERSION >= 40000
+
+/* GCC 4.1.[01] miscompiles __weak */
+#ifdef __KERNEL__
+# if GCC_VERSION >= 40100 &&  GCC_VERSION <= 40101
+#  error Your version of gcc miscompiles the __weak directive
+# endif
+#endif
+
+#define __used			__attribute__((__used__))
+#define __compiler_offsetof(a, b)					\
+	__builtin_offsetof(a, b)
+
+#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
+# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
+#endif
+
+#if GCC_VERSION >= 40300
+/* Mark functions as cold. gcc will assume any path leading to a call
+ * to them will be unlikely.  This means a lot of manual unlikely()s
+ * are unnecessary now for any paths leading to the usual suspects
+ * like BUG(), printk(), panic() etc. [but let's keep them for now for
+ * older compilers]
+ *
+ * Early snapshots of gcc 4.3 don't support this and we can't detect this
+ * in the preprocessor, but we can live with this because they're unreleased.
+ * Maketime probing would be overkill here.
+ *
+ * gcc also has a __attribute__((__hot__)) to move hot functions into
+ * a special section, but I don't see any sense in this right now in
+ * the kernel context
+ */
+#define __cold			__attribute__((__cold__))
+
+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+
+#ifndef __CHECKER__
+# define __compiletime_warning(message) __attribute__((warning(message)))
+# define __compiletime_error(message) __attribute__((error(message)))
+#endif /* __CHECKER__ */
+#endif /* GCC_VERSION >= 40300 */
+
+#if GCC_VERSION >= 40500
+/*
+ * Mark a position in code as unreachable.  This can be used to
+ * suppress control flow warnings after asm blocks that transfer
+ * control elsewhere.
+ *
+ * Early snapshots of gcc 4.5 don't support this and we can't detect
+ * this in the preprocessor, but we can live with this because they're
+ * unreleased.  Really, we need to have autoconf for the kernel.
+ */
+#define unreachable() __builtin_unreachable()
+
+/* Mark a function definition as prohibited from being cloned. */
+#define __noclone	__attribute__((__noclone__))
+
+#endif /* GCC_VERSION >= 40500 */
+
+#if GCC_VERSION >= 40600
+/*
+ * Tell the optimizer that something else uses this function or variable.
+ */
+#define __visible	__attribute__((externally_visible))
+#endif
+
+/*
+ * GCC 'asm goto' miscompiles certain code sequences:
+ *
+ *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
+ *
+ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
+ *
+ * (asm goto is automatically volatile - the naming reflects this.)
+ */
+#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
+
+#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
+#if GCC_VERSION >= 40400
+#define __HAVE_BUILTIN_BSWAP32__
+#define __HAVE_BUILTIN_BSWAP64__
+#endif
+#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
+#define __HAVE_BUILTIN_BSWAP16__
+#endif
+#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
+
+#endif	/* gcc version >= 40000 specific checks */
 
 #if !defined(__noclone)
 #define __noclone	/* not needed */
diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
deleted file mode 100644
index 7d89febe4d79..000000000000
--- a/include/linux/compiler-gcc3.h
+++ /dev/null
@@ -1,23 +0,0 @@
-#ifndef __LINUX_COMPILER_H
-#error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
-#endif
-
-#if GCC_VERSION < 30200
-# error Sorry, your compiler is too old - please upgrade it.
-#endif
-
-#if GCC_VERSION >= 30300
-# define __used			__attribute__((__used__))
-#else
-# define __used			__attribute__((__unused__))
-#endif
-
-#if GCC_VERSION >= 30400
-#define __must_check		__attribute__((warn_unused_result))
-#endif
-
-#ifdef CONFIG_GCOV_KERNEL
-# if GCC_VERSION < 30400
-#   error "GCOV profiling support for gcc versions below 3.4 not included"
-# endif /* __GNUC_MINOR__ */
-#endif /* CONFIG_GCOV_KERNEL */
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
deleted file mode 100644
index 2507fd2a1eb4..000000000000
--- a/include/linux/compiler-gcc4.h
+++ /dev/null
@@ -1,88 +0,0 @@
-#ifndef __LINUX_COMPILER_H
-#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
-#endif
-
-/* GCC 4.1.[01] miscompiles __weak */
-#ifdef __KERNEL__
-# if GCC_VERSION >= 40100 &&  GCC_VERSION <= 40101
-#  error Your version of gcc miscompiles the __weak directive
-# endif
-#endif
-
-#define __used			__attribute__((__used__))
-#define __must_check 		__attribute__((warn_unused_result))
-#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
-
-#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
-# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
-#endif
-
-#if GCC_VERSION >= 40300
-/* Mark functions as cold. gcc will assume any path leading to a call
-   to them will be unlikely.  This means a lot of manual unlikely()s
-   are unnecessary now for any paths leading to the usual suspects
-   like BUG(), printk(), panic() etc. [but let's keep them for now for
-   older compilers]
-
-   Early snapshots of gcc 4.3 don't support this and we can't detect this
-   in the preprocessor, but we can live with this because they're unreleased.
-   Maketime probing would be overkill here.
-
-   gcc also has a __attribute__((__hot__)) to move hot functions into
-   a special section, but I don't see any sense in this right now in
-   the kernel context */
-#define __cold			__attribute__((__cold__))
-
-#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
-
-#ifndef __CHECKER__
-# define __compiletime_warning(message) __attribute__((warning(message)))
-# define __compiletime_error(message) __attribute__((error(message)))
-#endif /* __CHECKER__ */
-#endif /* GCC_VERSION >= 40300 */
-
-#if GCC_VERSION >= 40500
-/*
- * Mark a position in code as unreachable.  This can be used to
- * suppress control flow warnings after asm blocks that transfer
- * control elsewhere.
- *
- * Early snapshots of gcc 4.5 don't support this and we can't detect
- * this in the preprocessor, but we can live with this because they're
- * unreleased.  Really, we need to have autoconf for the kernel.
- */
-#define unreachable() __builtin_unreachable()
-
-/* Mark a function definition as prohibited from being cloned. */
-#define __noclone	__attribute__((__noclone__))
-
-#endif /* GCC_VERSION >= 40500 */
-
-#if GCC_VERSION >= 40600
-/*
- * Tell the optimizer that something else uses this function or variable.
- */
-#define __visible __attribute__((externally_visible))
-#endif
-
-/*
- * GCC 'asm goto' miscompiles certain code sequences:
- *
- *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
- *
- * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
- * Fixed in GCC 4.8.2 and later versions.
- *
- * (asm goto is automatically volatile - the naming reflects this.)
- */
-#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
-
-#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
-#if GCC_VERSION >= 40400
-#define __HAVE_BUILTIN_BSWAP32__
-#define __HAVE_BUILTIN_BSWAP64__
-#endif
-#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
-#define __HAVE_BUILTIN_BSWAP16__
-#endif
-#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
diff --git a/include/linux/compiler-gcc5.h b/include/linux/compiler-gcc5.h
deleted file mode 100644
index cdd1cc202d51..000000000000
--- a/include/linux/compiler-gcc5.h
+++ /dev/null
@@ -1,66 +0,0 @@
-#ifndef __LINUX_COMPILER_H
-#error "Please don't include <linux/compiler-gcc5.h> directly, include <linux/compiler.h> instead."
-#endif
-
-#define __used				__attribute__((__used__))
-#define __must_check			__attribute__((warn_unused_result))
-#define __compiler_offsetof(a, b)	__builtin_offsetof(a, b)
-
-/* Mark functions as cold. gcc will assume any path leading to a call
-   to them will be unlikely.  This means a lot of manual unlikely()s
-   are unnecessary now for any paths leading to the usual suspects
-   like BUG(), printk(), panic() etc. [but let's keep them for now for
-   older compilers]
-
-   Early snapshots of gcc 4.3 don't support this and we can't detect this
-   in the preprocessor, but we can live with this because they're unreleased.
-   Maketime probing would be overkill here.
-
-   gcc also has a __attribute__((__hot__)) to move hot functions into
-   a special section, but I don't see any sense in this right now in
-   the kernel context */
-#define __cold			__attribute__((__cold__))
-
-#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
-
-#ifndef __CHECKER__
-# define __compiletime_warning(message) __attribute__((warning(message)))
-# define __compiletime_error(message) __attribute__((error(message)))
-#endif /* __CHECKER__ */
-
-/*
- * Mark a position in code as unreachable.  This can be used to
- * suppress control flow warnings after asm blocks that transfer
- * control elsewhere.
- *
- * Early snapshots of gcc 4.5 don't support this and we can't detect
- * this in the preprocessor, but we can live with this because they're
- * unreleased.  Really, we need to have autoconf for the kernel.
- */
-#define unreachable() __builtin_unreachable()
-
-/* Mark a function definition as prohibited from being cloned. */
-#define __noclone	__attribute__((__noclone__))
-
-/*
- * Tell the optimizer that something else uses this function or variable.
- */
-#define __visible __attribute__((externally_visible))
-
-/*
- * GCC 'asm goto' miscompiles certain code sequences:
- *
- *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
- *
- * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
- * Fixed in GCC 4.8.2 and later versions.
- *
- * (asm goto is automatically volatile - the naming reflects this.)
- */
-#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
-
-#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
-#define __HAVE_BUILTIN_BSWAP32__
-#define __HAVE_BUILTIN_BSWAP64__
-#define __HAVE_BUILTIN_BSWAP16__
-#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */