Define register_t using bits/typesizes.h macros.

Currently register_t is, unlike all other types in sys/types.h,
defined using a GCC extension (__attribute__((mode(word)))), falling
back to ‘int’ if the extension is unavailable.  This is a potential
ABI compatibility hazard for people using non-GNU compilers with
glibc.  It’s also unnecessary; the bits/typesizes.h mechanism can
handle all of the existing variation in the definition.  In most
cases, defining __REGISTER_T_TYPE as __SWORD_TYPE is sufficient.
Special handling is necessary for MIPS n32 and x86-64 x32, where
__SWORD_TYPE is ‘int’ and the appropriate type for register_t is
‘long long’.  Unfortunately, this means we need to create a new
bits/typesizes.h variant for linux/mips.  This variant is based
on the top-level bits/typesizes.h, not linux/generic/bits/typesizes.h,
to match the existing MIPS ABIs.

Tested using build-many-glibcs.  The c++-types test confirms that the
physical type of register_t does not change on any supported platform.

	* posix/sys/types.h: Typedef register_t as __register_t.
        * posix/bits/types.h: Typedef __register_t using __REGISTER_T_TYPE.

	* bits/typesizes.h
        * sysdeps/mach/hurd/bits/typesizes.h
        * sysdeps/unix/sysv/linux/alpha/bits/typesizes.h
        * sysdeps/unix/sysv/linux/generic/bits/typesizes.h
        * sysdeps/unix/sysv/linux/s390/bits/typesizes.h
        * sysdeps/unix/sysv/linux/sparc/bits/typesizes.h:
        Define __REGISTER_T_TYPE as __SWORD_TYPE.

        * sysdeps/unix/sysv/linux/mips/bits/typesizes.h:
        New file (copied from bits/typesizes.h).
        Define __REGISTER_T_TYPE as __SWORD_TYPE for o32 and n64 ABIs.
        Define __REGISTER_T_TYPE as __SQUAD_TYPE for n32.
        * sysdeps/unix/sysv/linux/x86/bits/typesizes.h:
        Define __REGISTER_T_TYPE as __SWORD_TYPE for o32 and 64-bit ABIs.
        Define __REGISTER_T_TYPE as __SQUAD_TYPE for x32.

10 files changed, 102 insertions, 5 deletions

diff --git a/bits/typesizes.h b/bits/typesizes.h
index 014c9aab21..f5c8161fc9 100644
--- a/bits/typesizes.h
+++ b/bits/typesizes.h
@@ -60,6 +60,7 @@
 #define __SYSCALL_SLONG_TYPE	__SLONGWORD_TYPE
 #define __SYSCALL_ULONG_TYPE	__ULONGWORD_TYPE
 #define __CPU_MASK_TYPE 	__ULONGWORD_TYPE
+#define __REGISTER_T_TYPE	__SWORD_TYPE
 
 #ifdef __LP64__
 /* Tell the libc code that off_t and off64_t are actually the same type
diff --git a/posix/bits/types.h b/posix/bits/types.h
index adba926b45..78c47ffa06 100644
--- a/posix/bits/types.h
+++ b/posix/bits/types.h
@@ -222,6 +222,9 @@ typedef int __sig_atomic_t;
 __STD_TYPE __TIME64_T_TYPE __time64_t;
 #endif
 
+/* BSD: Size of a general-purpose integer register.  */
+__STD_TYPE __REGISTER_T_TYPE __register_t;
+
 #undef __STD_TYPE
 
 #endif /* bits/types.h */
diff --git a/posix/sys/types.h b/posix/sys/types.h
index c9241e40b4..1838bdd851 100644
--- a/posix/sys/types.h
+++ b/posix/sys/types.h
@@ -160,11 +160,8 @@ typedef __uint16_t u_int16_t;
 typedef __uint32_t u_int32_t;
 typedef __uint64_t u_int64_t;
 
-#if __GNUC_PREREQ (2, 7)
-typedef int register_t __attribute__ ((__mode__ (__word__)));
-#else
-typedef int register_t;
-#endif
+/* Type of a general-purpose integer register (BSD).  */
+typedef __register_t register_t;
 
 /* Some code from BIND tests this macro to see if the types above are
    defined.  */
diff --git a/sysdeps/mach/hurd/bits/typesizes.h b/sysdeps/mach/hurd/bits/typesizes.h
index b429379d7d..f950bbf5d8 100644
--- a/sysdeps/mach/hurd/bits/typesizes.h
+++ b/sysdeps/mach/hurd/bits/typesizes.h
@@ -60,6 +60,7 @@
 #define __SYSCALL_SLONG_TYPE	__SLONGWORD_TYPE
 #define __SYSCALL_ULONG_TYPE	__ULONGWORD_TYPE
 #define __CPU_MASK_TYPE 	__ULONGWORD_TYPE
+#define __REGISTER_T_TYPE	__SWORD_TYPE
 
 /* Number of descriptors that can fit in an `fd_set'.  */
 #define	__FD_SETSIZE		256
diff --git a/sysdeps/unix/sysv/linux/alpha/bits/typesizes.h b/sysdeps/unix/sysv/linux/alpha/bits/typesizes.h
index 30356ba6d6..44e5381822 100644
--- a/sysdeps/unix/sysv/linux/alpha/bits/typesizes.h
+++ b/sysdeps/unix/sysv/linux/alpha/bits/typesizes.h
@@ -60,6 +60,7 @@
 #define __SYSCALL_ULONG_TYPE	__ULONGWORD_TYPE
 #define __CPU_MASK_TYPE 	__ULONGWORD_TYPE
 #define __FSWORD_T_TYPE		__S32_TYPE
+#define __REGISTER_T_TYPE	__SWORD_TYPE
 
 /* Tell the libc code that off_t and off64_t are actually the same type
    for all ABI purposes, even if possibly expressed as different base types
diff --git a/sysdeps/unix/sysv/linux/generic/bits/typesizes.h b/sysdeps/unix/sysv/linux/generic/bits/typesizes.h
index a916dea047..47b91568dd 100644
--- a/sysdeps/unix/sysv/linux/generic/bits/typesizes.h
+++ b/sysdeps/unix/sysv/linux/generic/bits/typesizes.h
@@ -61,6 +61,7 @@
 #define __SYSCALL_SLONG_TYPE	__SLONGWORD_TYPE
 #define __SYSCALL_ULONG_TYPE	__ULONGWORD_TYPE
 #define __CPU_MASK_TYPE 	__ULONGWORD_TYPE
+#define __REGISTER_T_TYPE	__SWORD_TYPE
 
 #ifdef __LP64__
 /* Tell the libc code that off_t and off64_t are actually the same type
diff --git a/sysdeps/unix/sysv/linux/mips/bits/typesizes.h b/sysdeps/unix/sysv/linux/mips/bits/typesizes.h
new file mode 100644
index 0000000000..1132670b1c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mips/bits/typesizes.h
@@ -0,0 +1,89 @@
+/* bits/typesizes.h -- underlying types for *_t.  For the MIPS Linux ABI.
+   Copyright (C) 2011-2019 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_TYPES_H
+# error "Never include <bits/typesizes.h> directly; use <sys/types.h> instead."
+#endif
+
+#ifndef	_BITS_TYPESIZES_H
+#define	_BITS_TYPESIZES_H	1
+
+/* See <bits/types.h> for the meaning of these macros.  This file exists so
+   that <bits/types.h> need not vary across different GNU platforms.  */
+
+#define __DEV_T_TYPE		__UQUAD_TYPE
+#define __UID_T_TYPE		__U32_TYPE
+#define __GID_T_TYPE		__U32_TYPE
+#define __INO_T_TYPE		__ULONGWORD_TYPE
+#define __INO64_T_TYPE		__UQUAD_TYPE
+#define __MODE_T_TYPE		__U32_TYPE
+#define __NLINK_T_TYPE		__UWORD_TYPE
+#define __OFF_T_TYPE		__SLONGWORD_TYPE
+#define __OFF64_T_TYPE		__SQUAD_TYPE
+#define __PID_T_TYPE		__S32_TYPE
+#define __RLIM_T_TYPE		__ULONGWORD_TYPE
+#define __RLIM64_T_TYPE		__UQUAD_TYPE
+#define	__BLKCNT_T_TYPE		__SLONGWORD_TYPE
+#define	__BLKCNT64_T_TYPE	__SQUAD_TYPE
+#define	__FSBLKCNT_T_TYPE	__ULONGWORD_TYPE
+#define	__FSBLKCNT64_T_TYPE	__UQUAD_TYPE
+#define	__FSFILCNT_T_TYPE	__ULONGWORD_TYPE
+#define	__FSFILCNT64_T_TYPE	__UQUAD_TYPE
+#define	__FSWORD_T_TYPE		__SWORD_TYPE
+#define	__ID_T_TYPE		__U32_TYPE
+#define __CLOCK_T_TYPE		__SLONGWORD_TYPE
+#define __TIME_T_TYPE		__SLONGWORD_TYPE
+#define __USECONDS_T_TYPE	__U32_TYPE
+#define __SUSECONDS_T_TYPE	__SLONGWORD_TYPE
+#define __DADDR_T_TYPE		__S32_TYPE
+#define __KEY_T_TYPE		__S32_TYPE
+#define __CLOCKID_T_TYPE	__S32_TYPE
+#define __TIMER_T_TYPE		void *
+#define __BLKSIZE_T_TYPE	__SLONGWORD_TYPE
+#define __FSID_T_TYPE		struct { int __val[2]; }
+#define __SSIZE_T_TYPE		__SWORD_TYPE
+#define __SYSCALL_SLONG_TYPE	__SLONGWORD_TYPE
+#define __SYSCALL_ULONG_TYPE	__ULONGWORD_TYPE
+#define __CPU_MASK_TYPE 	__ULONGWORD_TYPE
+
+#if defined _ABIN32 && _MIPS_SIM == _ABIN32
+#define __REGISTER_T_TYPE	__SQUAD_TYPE
+#else
+#define __REGISTER_T_TYPE	__SWORD_TYPE
+#endif
+
+#ifdef __LP64__
+/* Tell the libc code that off_t and off64_t are actually the same type
+   for all ABI purposes, even if possibly expressed as different base types
+   for C type-checking purposes.  */
+# define __OFF_T_MATCHES_OFF64_T	1
+
+/* Same for ino_t and ino64_t.  */
+# define __INO_T_MATCHES_INO64_T	1
+
+/* And for __rlim_t and __rlim64_t.  */
+# define __RLIM_T_MATCHES_RLIM64_T	1
+#else
+# define __RLIM_T_MATCHES_RLIM64_T	0
+#endif
+
+/* Number of descriptors that can fit in an `fd_set'.  */
+#define	__FD_SETSIZE		1024
+
+
+#endif /* bits/typesizes.h */
diff --git a/sysdeps/unix/sysv/linux/s390/bits/typesizes.h b/sysdeps/unix/sysv/linux/s390/bits/typesizes.h
index 45f70184ea..91c601d0fe 100644
--- a/sysdeps/unix/sysv/linux/s390/bits/typesizes.h
+++ b/sysdeps/unix/sysv/linux/s390/bits/typesizes.h
@@ -66,6 +66,7 @@
 #define __SYSCALL_SLONG_TYPE	__SLONGWORD_TYPE
 #define __SYSCALL_ULONG_TYPE	__ULONGWORD_TYPE
 #define __CPU_MASK_TYPE 	__ULONGWORD_TYPE
+#define __REGISTER_T_TYPE	__SWORD_TYPE
 
 #ifdef __s390x__
 /* Tell the libc code that off_t and off64_t are actually the same type
diff --git a/sysdeps/unix/sysv/linux/sparc/bits/typesizes.h b/sysdeps/unix/sysv/linux/sparc/bits/typesizes.h
index 1f3bbc8002..d19742d932 100644
--- a/sysdeps/unix/sysv/linux/sparc/bits/typesizes.h
+++ b/sysdeps/unix/sysv/linux/sparc/bits/typesizes.h
@@ -60,6 +60,7 @@
 #define __SYSCALL_SLONG_TYPE	__SLONGWORD_TYPE
 #define __SYSCALL_ULONG_TYPE	__ULONGWORD_TYPE
 #define __CPU_MASK_TYPE 	__ULONGWORD_TYPE
+#define __REGISTER_T_TYPE	__SWORD_TYPE
 
 #if defined __arch64__ || defined __sparcv9
 /* Tell the libc code that off_t and off64_t are actually the same type
diff --git a/sysdeps/unix/sysv/linux/x86/bits/typesizes.h b/sysdeps/unix/sysv/linux/x86/bits/typesizes.h
index d084145597..67ebbb2e17 100644
--- a/sysdeps/unix/sysv/linux/x86/bits/typesizes.h
+++ b/sysdeps/unix/sysv/linux/x86/bits/typesizes.h
@@ -30,9 +30,11 @@
 #if defined __x86_64__ && defined __ILP32__
 # define __SYSCALL_SLONG_TYPE	__SQUAD_TYPE
 # define __SYSCALL_ULONG_TYPE	__UQUAD_TYPE
+# define __REGISTER_T_TYPE	__SQUAD_TYPE
 #else
 # define __SYSCALL_SLONG_TYPE	__SLONGWORD_TYPE
 # define __SYSCALL_ULONG_TYPE	__ULONGWORD_TYPE
+# define __REGISTER_T_TYPE	__SWORD_TYPE
 #endif
 
 #define __DEV_T_TYPE		__UQUAD_TYPE