bits/byteswap-common.h: import recent headers from glibc

On systems where uClibc doesn't provide an arch specific byteswap.h,
we fall back on bits/byteswap-common.h.  However, there is a bug
in this header in the __bswap_constant_64(x) macro.  If, for example,
a double is passed, we get 'invalid operands to binary &' in which we
mismatch a 'double' and 'long long unsigned int'.  The newer glibc
headers fix this and so we import them.  Also, since the inclusion of
byteswap.h is not appropriate for assembly code, we guard a portion
of endian.h which uses byteswap.h from inclusion in any assembly.

This is needed, for example, for f2fs-tools 1.6.0 on 32-bit big
endian PowerPC.

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>

2 files changed, 91 insertions, 52 deletions

diff --git a/libc/sysdeps/linux/common/bits/byteswap-16.h b/libc/sysdeps/linux/common/bits/byteswap-16.h
new file mode 100644
index 000000000..8063aa82d
--- /dev/null
+++ b/libc/sysdeps/linux/common/bits/byteswap-16.h
@@ -0,0 +1,34 @@
+/* Macros to swap the order of bytes in 16-bit integer values.
+   Copyright (C) 2012-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_BYTESWAP_H
+# error "Never use <bits/byteswap-16.h> directly; include <byteswap.h> instead."
+#endif
+
+#ifdef __GNUC__
+# define __bswap_16(x) \
+    (__extension__							      \
+     ({ unsigned short int __bsx = (unsigned short int) (x);		      \
+       __bswap_constant_16 (__bsx); }))
+#else
+static __inline unsigned short int
+__bswap_16 (unsigned short int __bsx)
+{
+  return __bswap_constant_16 (__bsx);
+}
+#endif
diff --git a/libc/sysdeps/linux/common/bits/byteswap-common.h b/libc/sysdeps/linux/common/bits/byteswap-common.h
index 4941d4768..0effea689 100644
--- a/libc/sysdeps/linux/common/bits/byteswap-common.h
+++ b/libc/sysdeps/linux/common/bits/byteswap-common.h
@@ -1,5 +1,5 @@
 /* Macros to swap the order of bytes in integer values.
-   Copyright (C) 1997,1998,2000,2001,2002,2005 Free Software Foundation, Inc.
+   Copyright (C) 1997-2016 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -16,54 +16,40 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if !defined _BYTESWAP_H && !defined _NETINET_IN_H
+#if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H
 # error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
 #endif
 
 #ifndef _BITS_BYTESWAP_H
 #define _BITS_BYTESWAP_H 1
 
+#include <features.h>
+#include <bits/types.h>
+
 /* Swap bytes in 16 bit value.  */
 #define __bswap_constant_16(x) \
-     ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))
+	((unsigned short int)((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))
 
-#ifndef __bswap_non_constant_16
-# define __bswap_non_constant_16(x) __bswap_constant_16(x)
-#endif
-#ifdef __GNUC__
-# define __bswap_16(x) \
-    (__extension__							      \
-     ({ unsigned short int __bsv, __bsx = (x);				      \
-	if (__builtin_constant_p (__bsx))				      \
-	  __bsv = __bswap_constant_16 (__bsx);				      \
-	else								      \
-	  __bsv = __bswap_non_constant_16 (__bsx);			      \
-	__bsv; }))
-#else
-static __inline unsigned short int
-__bswap_16 (unsigned short int __bsx)
-{
-  return __bswap_constant_16 (__bsx);
-}
-#endif
+/* Get __bswap_16.  */
+#include <bits/byteswap-16.h>
 
 /* Swap bytes in 32 bit value.  */
 #define __bswap_constant_32(x) \
      ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >>  8) |	      \
       (((x) & 0x0000ff00u) <<  8) | (((x) & 0x000000ffu) << 24))
 
-#ifndef __bswap_non_constant_32
-# define __bswap_non_constant_32(x) __bswap_constant_32(x)
-#endif
 #ifdef __GNUC__
-# define __bswap_32(x) \
-    (__extension__							      \
-     ({ unsigned int __bsv, __bsx = (x);				      \
-	if (__builtin_constant_p (__bsx))				      \
-	  __bsv = __bswap_constant_32 (__bsx);				      \
-	else								      \
-	  __bsv = __bswap_non_constant_32 (__bsx);			      \
-	__bsv; }))
+# if __GNUC_PREREQ (4, 3)
+static __inline unsigned int
+__bswap_32 (unsigned int __bsx)
+{
+  return __builtin_bswap32 (__bsx);
+}
+# else
+#  define __bswap_32(x) \
+  (__extension__							      \
+   ({ unsigned int __bsx = (x); __bswap_constant_32 (__bsx); }))
+# endif
 #else
 static __inline unsigned int
 __bswap_32 (unsigned int __bsx)
@@ -72,8 +58,40 @@ __bswap_32 (unsigned int __bsx)
 }
 #endif
 
-#if defined __GNUC__ && __GNUC__ >= 2
 /* Swap bytes in 64 bit value.  */
+#if __GNUC_PREREQ (2, 0)
+# define __bswap_constant_64(x) \
+     (__extension__ ((((x) & 0xff00000000000000ull) >> 56)		      \
+		     | (((x) & 0x00ff000000000000ull) >> 40)		      \
+		     | (((x) & 0x0000ff0000000000ull) >> 24)		      \
+		     | (((x) & 0x000000ff00000000ull) >> 8)		      \
+		     | (((x) & 0x00000000ff000000ull) << 8)		      \
+		     | (((x) & 0x0000000000ff0000ull) << 24)		      \
+		     | (((x) & 0x000000000000ff00ull) << 40)		      \
+		     | (((x) & 0x00000000000000ffull) << 56)))
+
+# if __GNUC_PREREQ (4, 3)
+static __inline __uint64_t
+__bswap_64 (__uint64_t __bsx)
+{
+  return __builtin_bswap64 (__bsx);
+}
+# else
+#  define __bswap_64(x) \
+     (__extension__							      \
+      ({ union { __extension__ __uint64_t __ll;				      \
+		 unsigned int __l[2]; } __w, __r;			      \
+	 if (__builtin_constant_p (x))					      \
+	   __r.__ll = __bswap_constant_64 (x);				      \
+	 else								      \
+	   {								      \
+	     __w.__ll = (x);						      \
+	     __r.__l[0] = __bswap_32 (__w.__l[1]);			      \
+	     __r.__l[1] = __bswap_32 (__w.__l[0]);			      \
+	   }								      \
+	 __r.__ll; }))
+# endif
+#else
 # define __bswap_constant_64(x) \
      ((((x) & 0xff00000000000000ull) >> 56)				      \
       | (((x) & 0x00ff000000000000ull) >> 40)				      \
@@ -84,24 +102,11 @@ __bswap_32 (unsigned int __bsx)
       | (((x) & 0x000000000000ff00ull) << 40)				      \
       | (((x) & 0x00000000000000ffull) << 56))
 
-# ifndef __bswap_non_constant_64
-#  define __bswap_non_constant_64(x) \
-     (__extension__							      \
-      ({ union { __extension__ unsigned long long int __ll;		      \
-		 unsigned int __l[2]; } __w, __r;			      \
-	 __w.__ll = (x);						      \
-	 __r.__l[0] = __bswap_non_constant_32 (__w.__l[1]);		      \
-	 __r.__l[1] = __bswap_non_constant_32 (__w.__l[0]);		      \
-	 __r.__ll; }))
-# endif
-# define __bswap_64(x) \
-     (__extension__							      \
-      ({ __extension__ unsigned long long int __ll;			      \
-         if (__builtin_constant_p (x))					      \
-	   __ll = __bswap_constant_64 (x);				      \
-	 else								      \
-	   __ll = __bswap_non_constant_64 (x);				      \
-	 __ll; }))
+static __inline __uint64_t
+__bswap_64 (__uint64_t __bsx)
+{
+  return __bswap_constant_64 (__bsx);
+}
 #endif
 
 #endif /* _BITS_BYTESWAP_H */