compiler*.h: sync include/linux/compiler*.h with Linux 4.5-rc6

Copy these from Linux v4.5-rc6 tag.

This is needed so that we can keep up with newer gcc versions.  Note
that we don't have the uapi/ hierarchy from the kernel so continue to
use <linux/types.h>

Signed-off-by: Tom Rini <[email protected]>

Author: trini

include/linux/compiler-gcc.h

@@ -5,14 +5,28 @@
 /*
  * Common definitions for all gcc versions go here.
  */
-#define GCC_VERSION (__GNUC__ * 10000 \
-		   + __GNUC_MINOR__ * 100 \
-		   + __GNUC_PATCHLEVEL__)
-
+#define GCC_VERSION (__GNUC__ * 10000		\
+		     + __GNUC_MINOR__ * 100	\
+		     + __GNUC_PATCHLEVEL__)
 
 /* Optimization barrier */
+
 /* The "volatile" is due to gcc bugs */
 #define barrier() __asm__ __volatile__("": : :"memory")
+/*
+ * This version is i.e. to prevent dead stores elimination on @ptr
+ * where gcc and llvm may behave differently when otherwise using
+ * normal barrier(): while gcc behavior gets along with a normal
+ * barrier(), llvm needs an explicit input variable to be assumed
+ * clobbered. The issue is as follows: while the inline asm might
+ * access any memory it wants, the compiler could have fit all of
+ * @ptr into memory registers instead, and since @ptr never escaped
+ * from that, it proofed that the inline asm wasn't touching any of
+ * it. This version works well with both compilers, i.e. we're telling
+ * the compiler that the inline asm absolutely may see the contents
+ * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
+ */
+#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
 
 /*
  * This macro obfuscates arithmetic on a variable address so that gcc
@@ -32,58 +46,63 @@
  * the inline assembly constraint from =g to =r, in this particular
  * case either is valid.
  */
-#define RELOC_HIDE(ptr, off)					\
-  ({ unsigned long __ptr;					\
-    __asm__ ("" : "=r"(__ptr) : "0"(ptr));		\
-    (typeof(ptr)) (__ptr + (off)); })
+#define RELOC_HIDE(ptr, off)						\
+({									\
+	unsigned long __ptr;						\
+	__asm__ ("" : "=r"(__ptr) : "0"(ptr));				\
+	(typeof(ptr)) (__ptr + (off));					\
+})
 
 /* Make the optimizer believe the variable can be manipulated arbitrarily. */
-#define OPTIMIZER_HIDE_VAR(var) __asm__ ("" : "=r" (var) : "0" (var))
+#define OPTIMIZER_HIDE_VAR(var)						\
+	__asm__ ("" : "=r" (var) : "0" (var))
 
 #ifdef __CHECKER__
-#define __must_be_array(arr) 0
+#define __must_be_array(a)	0
 #else
 /* &a[0] degrades to a pointer: a different type from an array */
-#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
+#define __must_be_array(a)	BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
 #endif
 
 /*
  * Force always-inline if the user requests it so via the .config,
  * or if gcc is too old:
  */
-#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
+#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) ||		\
     !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
-# define inline		inline		__attribute__((always_inline)) notrace
-# define __inline__	__inline__	__attribute__((always_inline)) notrace
-# define __inline	__inline	__attribute__((always_inline)) notrace
+#define inline		inline		__attribute__((always_inline)) notrace
+#define __inline__	__inline__	__attribute__((always_inline)) notrace
+#define __inline	__inline	__attribute__((always_inline)) notrace
 #else
 /* A lot of inline functions can cause havoc with function tracing */
-# define inline		inline		notrace
-# define __inline__	__inline__	notrace
-# define __inline	__inline	notrace
+#define inline		inline		notrace
+#define __inline__	__inline__	notrace
+#define __inline	__inline	notrace
 #endif
 
-#define __deprecated			__attribute__((deprecated))
-#ifndef __packed
-#define __packed			__attribute__((packed))
-#endif
-#ifndef __weak
-#define __weak				__attribute__((weak))
-#endif
+#define __always_inline	inline __attribute__((always_inline))
+#define  noinline	__attribute__((noinline))
+
+#define __deprecated	__attribute__((deprecated))
+#define __packed	__attribute__((packed))
+#define __weak		__attribute__((weak))
+#define __alias(symbol)	__attribute__((alias(#symbol)))
 
 /*
- * it doesn't make sense on ARM (currently the only user of __naked) to trace
- * naked functions because then mcount is called without stack and frame pointer
- * being set up and there is no chance to restore the lr register to the value
- * before mcount was called.
+ * it doesn't make sense on ARM (currently the only user of __naked)
+ * to trace naked functions because then mcount is called without
+ * stack and frame pointer being set up and there is no chance to
+ * restore the lr register to the value before mcount was called.
+ *
+ * The asm() bodies of naked functions often depend on standard calling
+ * conventions, therefore they must be noinline and noclone.
  *
- * The asm() bodies of naked functions often depend on standard calling conventions,
- * therefore they must be noinline and noclone.  GCC 4.[56] currently fail to enforce
- * this, so we must do so ourselves.  See GCC PR44290.
+ * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
+ * See GCC PR44290.
  */
-#define __naked				__attribute__((naked)) noinline __noclone notrace
+#define __naked		__attribute__((naked)) noinline __noclone notrace
 
-#define __noreturn			__attribute__((noreturn))
+#define __noreturn	__attribute__((noreturn))
 
 /*
  * From the GCC manual:
@@ -95,34 +114,170 @@
  * would be.
  * [...]
  */
-#ifndef __pure
-#define __pure				__attribute__((pure))
+#define __pure			__attribute__((pure))
+#define __aligned(x)		__attribute__((aligned(x)))
+#define __printf(a, b)		__attribute__((format(printf, a, b)))
+#define __scanf(a, b)		__attribute__((format(scanf, a, b)))
+#define __attribute_const__	__attribute__((__const__))
+#define __maybe_unused		__attribute__((unused))
+#define __always_unused		__attribute__((unused))
+
+/* 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
+/*
+ * When used with Link Time Optimization, gcc can optimize away C functions or
+ * variables which are referenced only from assembly code.  __visible tells the
+ * optimizer that something else uses this function or variable, thus preventing
+ * this.
+ */
+#define __visible	__attribute__((externally_visible))
 #endif
-#ifndef __aligned
-#define __aligned(x)			__attribute__((aligned(x)))
+
+
+#if GCC_VERSION >= 40900 && !defined(__CHECKER__)
+/*
+ * __assume_aligned(n, k): Tell the optimizer that the returned
+ * pointer can be assumed to be k modulo n. The second argument is
+ * optional (default 0), so we use a variadic macro to make the
+ * shorthand.
+ *
+ * Beware: Do not apply this to functions which may return
+ * ERR_PTRs. Also, it is probably unwise to apply it to functions
+ * returning extra information in the low bits (but in that case the
+ * compiler should see some alignment anyway, when the return value is
+ * massaged by 'flags = ptr & 3; ptr &= ~3;').
+ */
+#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
 #endif
-#define __printf(a, b)			__attribute__((format(printf, a, b)))
-#define __scanf(a, b)			__attribute__((format(scanf, a, b)))
-#define  noinline			__attribute__((noinline))
-#define __attribute_const__		__attribute__((__const__))
-#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 '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 */
+
+#if GCC_VERSION >= 50000
+#define KASAN_ABI_VERSION 4
+#elif GCC_VERSION >= 40902
+#define KASAN_ABI_VERSION 3
+#endif
+
+#if GCC_VERSION >= 40902
+/*
+ * Tell the compiler that address safety instrumentation (KASAN)
+ * should not be applied to that function.
+ * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
+ */
+#define __no_sanitize_address __attribute__((no_sanitize_address))
+#endif
+
+#endif	/* gcc version >= 40000 specific checks */
 
 #if !defined(__noclone)
 #define __noclone	/* not needed */
 #endif
 
+#if !defined(__no_sanitize_address)
+#define __no_sanitize_address
+#endif
+
 /*
  * A trick to suppress uninitialized variable warning without generating any
  * code
  */
 #define uninitialized_var(x) x = x
-
-#ifndef __always_inline
-#define __always_inline		inline __attribute__((always_inline))
-#endif