Post-cleanup 1: move libio.h back out of bits/.

We can't go very far with libio cleanups as long as we still have
_IO_MTSAFE_IO, and I am not tackling that in this patch series,
but we can at least make the maze of stdio-related headers a
little less complicated.

In this patch, libio.h moves back out of bits/ into the top level of
the libio subdirectory, and is merged with libio/bits/libio-ldbl.h
(which also used to be installed) and include/libio.h.  Since almost
no files include libio.h directly, this is quite straightforward.

libio.h is now always used with _LIBC defined, so all of the _LIBC ||
_GLIBCPP_USE_WCHAR_T conditionals are unnecessary.  Similarly, the
ifdef nest surrounding the definition of _IO_fwide_maybe_incompatible
can collapse down to a single SHLIB_COMPAT check.  I also took the
opportunity to add some checks for configuration botches to libio.h.

Installed stripped libraries are unchanged by this patch.

        * libio/bits/libio.h: Move back to libio/libio.h and adjust
        multiple-include guard to match.
        Merge contents of libio/bits/libio-ldbl.h and include/libio.h
        into this file.
        Remove preprocessor conditionals that are always true and/or
        redundant to other preprocessor conditionals in the same nest.
        Include shlib-compat.h unconditionally.
        Error out if _LIBC is not defined, or if _ISOMAC is defined,
        or if _IO_MTSAFE_IO is defined but _IO_lock_t_defined is not
        defined after including stdio.h.
        Use __BEGIN_DECLS/__END_DECLS.

        * libio/bits/libio-ldbl.h, include/bits/libio.h: Delete file.
        * include/stdio.h, libio/iolibio.h, libio/libioP.h: Include
        libio.h as <libio/libio.h> rather than as <bits/libio.h>.

4 files changed, 66 insertions, 63 deletions

diff --git a/libio/bits/libio-ldbl.h b/libio/bits/libio-ldbl.h
deleted file mode 100644
index aa39353ca5..0000000000
--- a/libio/bits/libio-ldbl.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/* -mlong-double-64 compatibility mode for libio functions.
-   Copyright (C) 2006-2018 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_LIBIO_LDBL_H
-#define _BITS_LIBIO_LDBL_H 1
-
-#ifndef _BITS_LIBIO_H
-# error "Never include <bits/libio-ldbl.h> directly; use <libio.h> instead."
-#endif
-
-__LDBL_REDIR_DECL (_IO_vfscanf)
-__LDBL_REDIR_DECL (_IO_vfprintf)
-
-#endif
diff --git a/libio/iolibio.h b/libio/iolibio.h
index 7814b1d4e5..52731b65f9 100644
--- a/libio/iolibio.h
+++ b/libio/iolibio.h
@@ -2,7 +2,7 @@
 #define _IOLIBIO_H 1
 
 #include <stdio.h>
-#include <bits/libio.h>
+#include <libio/libio.h>
 
 /* These emulate stdio functionality, but with a different name
    (_IO_ungetc instead of ungetc), and using _IO_FILE instead of FILE. */
diff --git a/libio/bits/libio.h b/libio/libio.h
index cefc2c855b..ff67e18c18 100644
--- a/libio/bits/libio.h
+++ b/libio/libio.h
@@ -25,11 +25,22 @@
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#ifndef _BITS_LIBIO_H
-#define _BITS_LIBIO_H 1
+#ifndef _LIBIO_H
+#define _LIBIO_H 1
+
+#ifndef _LIBC
+# error "libio.h should only be included when building glibc itself"
+#endif
+#ifdef _ISOMAC
+# error "libio.h should not be included under _ISOMAC"
+#endif
 
 #include <stdio.h>
 
+#if defined _IO_MTSAFE_IO && !defined _IO_lock_t_defined
+# error "Someone forgot to include stdio-lock.h"
+#endif
+
 #include <bits/_G_config.h>
 /* ALL of these should be defined in _G_config.h */
 #define _IO_fpos_t __fpos_t
@@ -46,6 +57,10 @@
 #define _IO_wint_t wint_t
 #define _IO_va_list __gnuc_va_list
 
+#include <shlib-compat.h>
+
+__BEGIN_DECLS
+
 /* compatibility defines */
 #define _STDIO_USES_IOSTREAM
 #define _IO_UNIFIED_JUMPTABLES 1
@@ -143,7 +158,6 @@ enum __codecvt_result
   __codecvt_noconv
 };
 
-#if defined _LIBC || defined _GLIBCPP_USE_WCHAR_T
 /* The order of the elements in the following struct must match the order
    of the virtual functions in the libstdc++ codecvt class.  */
 struct _IO_codecvt
@@ -198,7 +212,6 @@ struct _IO_wide_data
 
   const struct _IO_jump_t *_wide_vtable;
 };
-#endif
 
 
 #ifndef __cplusplus
@@ -236,17 +249,10 @@ extern void _IO_cookie_init (struct _IO_cookie_file *__cfile, int __read_write,
 			     void *__cookie, _IO_cookie_io_functions_t __fns);
 #endif
 
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 extern int __underflow (_IO_FILE *);
-#if defined _LIBC || defined _GLIBCPP_USE_WCHAR_T
 extern _IO_wint_t __wunderflow (_IO_FILE *);
 extern _IO_wint_t __wuflow (_IO_FILE *);
 extern _IO_wint_t __woverflow (_IO_FILE *, _IO_wint_t);
-#endif
 
 #if  __GNUC__ >= 3
 # define _IO_BE(expr, res) __builtin_expect ((expr), res)
@@ -261,7 +267,6 @@ extern _IO_wint_t __woverflow (_IO_FILE *, _IO_wint_t);
 	: *(unsigned char *) (_fp)->_IO_read_ptr)
 #define _IO_putc_unlocked(_ch, _fp) __putc_unlocked_body (_ch, _fp)
 
-#if defined _LIBC || defined _GLIBCPP_USE_WCHAR_T
 # define _IO_getwc_unlocked(_fp) \
   (_IO_BE ((_fp)->_wide_data == NULL					\
 	   || ((_fp)->_wide_data->_IO_read_ptr				\
@@ -273,7 +278,6 @@ extern _IO_wint_t __woverflow (_IO_FILE *, _IO_wint_t);
 	       >= (_fp)->_wide_data->_IO_write_end), 0)			\
    ? __woverflow (_fp, _wch)						\
    : (_IO_wint_t) (*(_fp)->_wide_data->_IO_write_ptr++ = (_wch)))
-#endif
 
 #define _IO_feof_unlocked(_fp) __feof_unlocked_body (_fp)
 #define _IO_ferror_unlocked(_fp) __ferror_unlocked_body (_fp)
@@ -319,28 +323,25 @@ extern _IO_off64_t _IO_seekpos (_IO_FILE *, _IO_off64_t, int);
 
 extern void _IO_free_backup_area (_IO_FILE *) __THROW;
 
-#if defined _LIBC || defined _GLIBCPP_USE_WCHAR_T
+
 extern _IO_wint_t _IO_getwc (_IO_FILE *__fp);
 extern _IO_wint_t _IO_putwc (wchar_t __wc, _IO_FILE *__fp);
 extern int _IO_fwide (_IO_FILE *__fp, int __mode) __THROW;
-# if __GNUC__ >= 2
+
 /* While compiling glibc we have to handle compatibility with very old
    versions.  */
-#  if defined _LIBC && defined SHARED
-#   include <shlib-compat.h>
-#   if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
-#    define _IO_fwide_maybe_incompatible \
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
+#  define _IO_fwide_maybe_incompatible \
   (__builtin_expect (&_IO_stdin_used == NULL, 0))
 extern const int _IO_stdin_used;
 weak_extern (_IO_stdin_used);
-#   endif
-#  endif
-#  ifndef _IO_fwide_maybe_incompatible
-#   define _IO_fwide_maybe_incompatible (0)
-#  endif
+#else
+# define _IO_fwide_maybe_incompatible (0)
+#endif
+
 /* A special optimized version of the function above.  It optimizes the
    case of initializing an unoriented byte stream.  */
-#  define _IO_fwide(__fp, __mode) \
+#define _IO_fwide(__fp, __mode) \
   ({ int __result = (__mode);						      \
      if (__result < 0 && ! _IO_fwide_maybe_incompatible)		      \
        {								      \
@@ -354,7 +355,6 @@ weak_extern (_IO_stdin_used);
      else								      \
        __result = _IO_fwide (__fp, __result);				      \
      __result; })
-# endif
 
 extern int _IO_vfwscanf (_IO_FILE * __restrict, const wchar_t * __restrict,
 			 _IO_va_list, int *__restrict);
@@ -362,14 +362,46 @@ extern int _IO_vfwprintf (_IO_FILE *__restrict, const wchar_t *__restrict,
 			  _IO_va_list);
 extern _IO_ssize_t _IO_wpadn (_IO_FILE *, wint_t, _IO_ssize_t);
 extern void _IO_free_wbackup_area (_IO_FILE *) __THROW;
-#endif
 
 #ifdef __LDBL_COMPAT
-# include <bits/libio-ldbl.h>
+__LDBL_REDIR_DECL (_IO_vfscanf)
+__LDBL_REDIR_DECL (_IO_vfprintf)
 #endif
 
-#ifdef __cplusplus
-}
-#endif
+libc_hidden_proto (__overflow)
+libc_hidden_proto (__underflow)
+libc_hidden_proto (__uflow)
+libc_hidden_proto (__woverflow)
+libc_hidden_proto (__wunderflow)
+libc_hidden_proto (__wuflow)
+libc_hidden_proto (_IO_free_backup_area)
+libc_hidden_proto (_IO_free_wbackup_area)
+libc_hidden_proto (_IO_padn)
+libc_hidden_proto (_IO_putc)
+libc_hidden_proto (_IO_sgetn)
+libc_hidden_proto (_IO_vfprintf)
+libc_hidden_proto (_IO_vfscanf)
+
+#ifdef _IO_MTSAFE_IO
+# undef _IO_peekc
+# undef _IO_flockfile
+# undef _IO_funlockfile
+# undef _IO_ftrylockfile
+
+# define _IO_peekc(_fp) _IO_peekc_locked (_fp)
+# if _IO_lock_inexpensive
+#  define _IO_flockfile(_fp) \
+  if (((_fp)->_flags & _IO_USER_LOCK) == 0) _IO_lock_lock (*(_fp)->_lock)
+#  define _IO_funlockfile(_fp) \
+  if (((_fp)->_flags & _IO_USER_LOCK) == 0) _IO_lock_unlock (*(_fp)->_lock)
+# else
+#  define _IO_flockfile(_fp) \
+  if (((_fp)->_flags & _IO_USER_LOCK) == 0) _IO_flockfile (_fp)
+#  define _IO_funlockfile(_fp) \
+  if (((_fp)->_flags & _IO_USER_LOCK) == 0) _IO_funlockfile (_fp)
+# endif
+#endif /* _IO_MTSAFE_IO */
+
+__END_DECLS
 
-#endif /* _BITS_LIBIO_H */
+#endif /* _LIBIO_H */
diff --git a/libio/libioP.h b/libio/libioP.h
index ac66f95f8d..8edc207277 100644
--- a/libio/libioP.h
+++ b/libio/libioP.h
@@ -43,7 +43,7 @@
 #include <math_ldbl_opt.h>
 
 #include <stdio.h>
-#include <bits/libio.h>
+#include <libio/libio.h>
 #include "iolibio.h"
 
 #ifdef __cplusplus