Fix C11 conformance issues

  On 25/07/2018 12:40, Joseph Myers wrote:
> On Wed, 25 Jul 2018, Adhemerval Zanella wrote:
> 
>> Checked on i686-linux-gnu and i686-gnu.
>>
>> 	* include/threads.h: Move to ...
>> 	* sysdeps/nptl/threads.h: ... here.
>> 	* sysdeps/htl/threads.h: New file.
> 
> To confirm: nptl/threads.h, not the wrapper you're moving, still gets 
> correctly installed as threads.h after this patch, while it remains the 
> case that no threads.h is installed for Hurd?
> 
> I think you need two separate versions of stdc-predef.h as well, so that 
> Hurd gets a version that defines __STDC_NO_THREADS__.  Then once there is 
> a C11 threads implementation for HTL, we can move back to just having a 
> single version of stdc-predef.h.  (There should also be a single version 
> of threads.h in that case, and we should aim to move towards a single 
> pthread.h shared between NPTL and HTL as well.)
> 

The patch below should fix it and the hurd specific stdc-predef.h with
__STDC_NO_THREADS__ defined. I would like to avoid duplicating a file
contents, but the other possible alternative which I can think of would
add a platform specific file (empty for nptl case and defining 
__STDC_NO_THREADS__ for htl) with the drawback of adding another
include on every compilation (due extra include). I think we can
live with a hurd specific stdc-predef.h for now.

---

[PATCH] Fix ISO C threads installed header and HURD assumption

Checked on both i686-linux-gnu and i686-gnu that both threads.h
and stdc-predef.h are the expected ones.

	* nptl/threads.h: Move to ...
	* sysdeps/nptl/threads.h: ... here.
	* sysdeps/hurd/stdc-predef.h: New file.
---
 ChangeLog                  |   6 ++
 nptl/threads.h             | 207 --------------------------------------------
 sysdeps/hurd/stdc-predef.h |  63 ++++++++++++++
 sysdeps/nptl/threads.h     | 208 ++++++++++++++++++++++++++++++++++++++++++++-
 4 files changed, 276 insertions(+), 208 deletions(-)
 delete mode 100644 nptl/threads.h
 create mode 100644 sysdeps/hurd/stdc-predef.h
  

On Wed, 25 Jul 2018, Adhemerval Zanella wrote:

> The patch below should fix it and the hurd specific stdc-predef.h with
> __STDC_NO_THREADS__ defined. I would like to avoid duplicating a file
> contents, but the other possible alternative which I can think of would
> add a platform specific file (empty for nptl case and defining 
> __STDC_NO_THREADS__ for htl) with the drawback of adding another
> include on every compilation (due extra include). I think we can
> live with a hurd specific stdc-predef.h for now.

This patch is OK.  The handling of precompiled headers in GCC is very 
fragile with regard to implicitly preincluded files and if stdc-predef.h 
were to include another header, there would be a significant chance of 
this breaking PCH.
  

On 07/25/2018 02:28 PM, Adhemerval Zanella wrote:
> [PATCH] Fix ISO C threads installed header and HURD assumption
> 
> Checked on both i686-linux-gnu and i686-gnu that both threads.h
> and stdc-predef.h are the expected ones.
> 
> 	* nptl/threads.h: Move to ...
> 	* sysdeps/nptl/threads.h: ... here.
> 	* sysdeps/hurd/stdc-predef.h: New file.

This is OK for 2.28. It is just movement of the normal threads.h to nptl
(not generic anymore), and the new stdc-predef.h for hurd. With the other
fixes that you and Joseph discussed coming in 2.29 or later.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

> ---
>  ChangeLog                  |   6 ++
>  nptl/threads.h             | 207 --------------------------------------------
>  sysdeps/hurd/stdc-predef.h |  63 ++++++++++++++
>  sysdeps/nptl/threads.h     | 208 ++++++++++++++++++++++++++++++++++++++++++++-
>  4 files changed, 276 insertions(+), 208 deletions(-)
>  delete mode 100644 nptl/threads.h
>  create mode 100644 sysdeps/hurd/stdc-predef.h
> 
> diff --git a/nptl/threads.h b/nptl/threads.h
> deleted file mode 100644
> index 9800f93..0000000
> --- a/nptl/threads.h
> +++ /dev/null
> @@ -1,207 +0,0 @@
> -/* ISO C11 Standard: 7.26 - Thread support library  <threads.h>.
> -   Copyright (C) 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 _THREADS_H
> -#define _THREADS_H	1
> -
> -#include <features.h>
> -#include <time.h>
> -
> -__BEGIN_DECLS
> -
> -#include <bits/pthreadtypes-arch.h>
> -#include <bits/types/struct_timespec.h>
> -
> -#ifndef __cplusplus
> -# define thread_local _Thread_local
> -#endif
> -
> -#define TSS_DTOR_ITERATIONS 4
> -typedef unsigned int tss_t;
> -typedef void (*tss_dtor_t) (void*);
> -
> -typedef unsigned long int thrd_t;
> -typedef int (*thrd_start_t) (void*);
> -
> -/* Exit and error codes.  */
> -enum
> -{
> -  thrd_success  = 0,
> -  thrd_busy     = 1,
> -  thrd_error    = 2,
> -  thrd_nomem    = 3,
> -  thrd_timedout = 4
> -};
> -
> -/* Mutex types.  */
> -enum
> -{
> -  mtx_plain     = 0,
> -  mtx_recursive = 1,
> -  mtx_timed     = 2
> -};
> -
> -typedef struct
> -{
> -  int __data __ONCE_ALIGNMENT;
> -} once_flag;
> -#define ONCE_FLAG_INIT { 0 }
> -
> -typedef union
> -{
> -  char __size[__SIZEOF_PTHREAD_MUTEX_T];
> -  long int __align __LOCK_ALIGNMENT;
> -} mtx_t;
> -
> -typedef union
> -{
> -  char __size[__SIZEOF_PTHREAD_COND_T];
> -  __extension__ long long int __align __LOCK_ALIGNMENT;
> -} cnd_t;
> -
> -/* Threads functions.  */
> -
> -/* Create a new thread executing the function __FUNC.  Arguments for __FUNC
> -   are passed through __ARG.  If succesful, __THR is set to new thread
> -   identifier.  */
> -extern int thrd_create (thrd_t *__thr, thrd_start_t __func, void *__arg);
> -
> -/* Check if __LHS and __RHS point to the same thread.  */
> -extern int thrd_equal (thrd_t __lhs, thrd_t __rhs);
> -
> -/* Return current thread identifier.  */
> -extern thrd_t thrd_current (void);
> -
> -/* Block current thread execution for at least the time pointed by
> -   __TIME_POINT.  The current thread may resume if receives a signal.  In
> -   that case, if __REMAINING is not NULL, the remaining time is stored in
> -   the object pointed by it.  */
> -extern int thrd_sleep (const struct timespec *__time_point,
> -		       struct timespec *__remaining);
> -
> -/* Terminate current thread execution, cleaning up any thread local
> -   storage and freeing resources.  Returns the value specified in __RES.  */
> -extern void thrd_exit (int __res) __attribute__ ((__noreturn__));
> -
> -/* Detach the thread identified by __THR from the current environment
> -   (it does not allow join or wait for it).  */
> -extern int thrd_detach (thrd_t __thr);
> -
> -/* Block current thread until execution of __THR is complete.  In case that
> -   __RES is not NULL, will store the return value of __THR when exiting.  */
> -extern int thrd_join (thrd_t __thr, int *__res);
> -
> -/* Stop current thread execution and call the scheduler to decide which
> -   thread should execute next.  The current thread may be selected by the
> -   scheduler to keep running.  */
> -extern void thrd_yield (void);
> -
> -#ifdef __USE_EXTERN_INLINES
> -/* Optimizations.  */
> -__extern_inline int
> -thrd_equal (thrd_t __thread1, thrd_t __thread2)
> -{
> -  return __thread1 == __thread2;
> -}
> -#endif
> -
> -
> -/* Mutex functions.  */
> -
> -/* Creates a new mutex object with type __TYPE.  If successful the new
> -   object is pointed by __MUTEX.  */
> -extern int mtx_init (mtx_t *__mutex, int __type);
> -
> -/* Block the current thread until the mutex pointed to by __MUTEX is
> -   unlocked.  In that case current thread will not be blocked.  */
> -extern int mtx_lock (mtx_t *__mutex);
> -
> -/* Block the current thread until the mutex pointed by __MUTEX is unlocked
> -   or time pointed by __TIME_POINT is reached.  In case the mutex is unlock,
> -   the current thread will not be blocked.  */
> -extern int mtx_timedlock (mtx_t *__restrict __mutex,
> -			  const struct timespec *__restrict __time_point);
> -
> -/* Try to lock the mutex pointed by __MUTEX without blocking.  If the mutex
> -   is free the current threads takes control of it, otherwise it returns
> -   immediately.  */
> -extern int mtx_trylock (mtx_t *__mutex);
> -
> -/* Unlock the mutex pointed by __MUTEX.  It may potentially awake other
> -   threads waiting on this mutex.  */
> -extern int mtx_unlock (mtx_t *__mutex);
> -
> -/* Destroy the mutex object pointed by __MUTEX.  */
> -extern void mtx_destroy (mtx_t *__mutex);
> -
> -
> -/* Call function __FUNC exactly once, even if invoked from several threads.
> -   All calls must be made with the same __FLAGS object.  */
> -extern void call_once (once_flag *__flag, void (*__func)(void));
> -
> -
> -/* Condition variable functions.  */
> -
> -/* Initialize new condition variable pointed by __COND.  */
> -extern int cnd_init (cnd_t *__cond);
> -
> -/* Unblock one thread that currently waits on condition variable pointed
> -   by __COND.  */
> -extern int cnd_signal (cnd_t *__cond);
> -
> -/* Unblock all threads currently waiting on condition variable pointed by
> -   __COND.  */
> -extern int cnd_broadcast (cnd_t *__cond);
> -
> -/* Block current thread on the condition variable pointed by __COND.  */
> -extern int cnd_wait (cnd_t *__cond, mtx_t *__mutex);
> -
> -/* Block current thread on the condition variable until condition variable
> -   pointed by __COND is signaled or time pointed by __TIME_POINT is
> -   reached.  */
> -extern int cnd_timedwait (cnd_t *__restrict __cond,
> -			  mtx_t *__restrict __mutex,
> -			  const struct timespec *__restrict __time_point);
> -
> -/* Destroy condition variable pointed by __cond and free all of its
> -   resources.  */
> -extern void cnd_destroy (cnd_t *__COND);
> -
> -
> -/* Thread specific storage functions.  */
> -
> -/* Create new thread-specific storage key and stores it in the object pointed
> -   by __TSS_ID.  If __DESTRUCTOR is not NULL, the function will be called when
> -   the thread terminates.  */
> -extern int tss_create (tss_t *__tss_id, tss_dtor_t __destructor);
> -
> -/* Return the value held in thread-specific storage for the current thread
> -   identified by __TSS_ID.  */
> -extern void *tss_get (tss_t __tss_id);
> -
> -/* Sets the value of the thread-specific storage identified by __TSS_ID for
> -   the current thread to __VAL.  */
> -extern int tss_set (tss_t __tss_id, void *__val);
> -
> -/* Destroys the thread-specific storage identified by __TSS_ID.  The
> -   destructor is not called until thrd_exit is called.  */
> -extern void tss_delete (tss_t __tss_id);
> -
> -__END_DECLS
> -
> -#endif /* _THREADS_H */
> diff --git a/sysdeps/hurd/stdc-predef.h b/sysdeps/hurd/stdc-predef.h
> new file mode 100644
> index 0000000..4c11188
> --- /dev/null
> +++ b/sysdeps/hurd/stdc-predef.h
> @@ -0,0 +1,63 @@
> +/* Copyright (C) 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	_STDC_PREDEF_H
> +#define	_STDC_PREDEF_H	1
> +
> +/* This header is separate from features.h so that the compiler can
> +   include it implicitly at the start of every compilation.  It must
> +   not itself include <features.h> or any other header that includes
> +   <features.h> because the implicit include comes before any feature
> +   test macros that may be defined in a source file before it first
> +   explicitly includes a system header.  GCC knows the name of this
> +   header in order to preinclude it.  */
> +
> +/* glibc's intent is to support the IEC 559 math functionality, real
> +   and complex.  If the GCC (4.9 and later) predefined macros
> +   specifying compiler intent are available, use them to determine
> +   whether the overall intent is to support these features; otherwise,
> +   presume an older compiler has intent to support these features and
> +   define these macros by default.  */
> +
> +#ifdef __GCC_IEC_559
> +# if __GCC_IEC_559 > 0
> +#  define __STDC_IEC_559__		1
> +# endif
> +#else
> +# define __STDC_IEC_559__		1
> +#endif
> +
> +#ifdef __GCC_IEC_559_COMPLEX
> +# if __GCC_IEC_559_COMPLEX > 0
> +#  define __STDC_IEC_559_COMPLEX__	1
> +# endif
> +#else
> +# define __STDC_IEC_559_COMPLEX__	1
> +#endif
> +
> +/* wchar_t uses Unicode 10.0.0.  Version 10.0 of the Unicode Standard is
> +   synchronized with ISO/IEC 10646:2017, fifth edition, plus
> +   the following additions from Amendment 1 to the fifth edition:
> +   - 56 emoji characters
> +   - 285 hentaigana
> +   - 3 additional Zanabazar Square characters */
> +#define __STDC_ISO_10646__		201706L
> +
> +/* We do not support C11 <threads.h>.  */
> +#define __STDC_NO_THREADS__		1
> +
> +#endif
> diff --git a/sysdeps/nptl/threads.h b/sysdeps/nptl/threads.h
> index 1090612..9800f93 100644
> --- a/sysdeps/nptl/threads.h
> +++ b/sysdeps/nptl/threads.h
> @@ -1 +1,207 @@
> -#include <nptl/threads.h>
> +/* ISO C11 Standard: 7.26 - Thread support library  <threads.h>.
> +   Copyright (C) 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 _THREADS_H
> +#define _THREADS_H	1
> +
> +#include <features.h>
> +#include <time.h>
> +
> +__BEGIN_DECLS
> +
> +#include <bits/pthreadtypes-arch.h>
> +#include <bits/types/struct_timespec.h>
> +
> +#ifndef __cplusplus
> +# define thread_local _Thread_local
> +#endif
> +
> +#define TSS_DTOR_ITERATIONS 4
> +typedef unsigned int tss_t;
> +typedef void (*tss_dtor_t) (void*);
> +
> +typedef unsigned long int thrd_t;
> +typedef int (*thrd_start_t) (void*);
> +
> +/* Exit and error codes.  */
> +enum
> +{
> +  thrd_success  = 0,
> +  thrd_busy     = 1,
> +  thrd_error    = 2,
> +  thrd_nomem    = 3,
> +  thrd_timedout = 4
> +};
> +
> +/* Mutex types.  */
> +enum
> +{
> +  mtx_plain     = 0,
> +  mtx_recursive = 1,
> +  mtx_timed     = 2
> +};
> +
> +typedef struct
> +{
> +  int __data __ONCE_ALIGNMENT;
> +} once_flag;
> +#define ONCE_FLAG_INIT { 0 }
> +
> +typedef union
> +{
> +  char __size[__SIZEOF_PTHREAD_MUTEX_T];
> +  long int __align __LOCK_ALIGNMENT;
> +} mtx_t;
> +
> +typedef union
> +{
> +  char __size[__SIZEOF_PTHREAD_COND_T];
> +  __extension__ long long int __align __LOCK_ALIGNMENT;
> +} cnd_t;
> +
> +/* Threads functions.  */
> +
> +/* Create a new thread executing the function __FUNC.  Arguments for __FUNC
> +   are passed through __ARG.  If succesful, __THR is set to new thread
> +   identifier.  */
> +extern int thrd_create (thrd_t *__thr, thrd_start_t __func, void *__arg);
> +
> +/* Check if __LHS and __RHS point to the same thread.  */
> +extern int thrd_equal (thrd_t __lhs, thrd_t __rhs);
> +
> +/* Return current thread identifier.  */
> +extern thrd_t thrd_current (void);
> +
> +/* Block current thread execution for at least the time pointed by
> +   __TIME_POINT.  The current thread may resume if receives a signal.  In
> +   that case, if __REMAINING is not NULL, the remaining time is stored in
> +   the object pointed by it.  */
> +extern int thrd_sleep (const struct timespec *__time_point,
> +		       struct timespec *__remaining);
> +
> +/* Terminate current thread execution, cleaning up any thread local
> +   storage and freeing resources.  Returns the value specified in __RES.  */
> +extern void thrd_exit (int __res) __attribute__ ((__noreturn__));
> +
> +/* Detach the thread identified by __THR from the current environment
> +   (it does not allow join or wait for it).  */
> +extern int thrd_detach (thrd_t __thr);
> +
> +/* Block current thread until execution of __THR is complete.  In case that
> +   __RES is not NULL, will store the return value of __THR when exiting.  */
> +extern int thrd_join (thrd_t __thr, int *__res);
> +
> +/* Stop current thread execution and call the scheduler to decide which
> +   thread should execute next.  The current thread may be selected by the
> +   scheduler to keep running.  */
> +extern void thrd_yield (void);
> +
> +#ifdef __USE_EXTERN_INLINES
> +/* Optimizations.  */
> +__extern_inline int
> +thrd_equal (thrd_t __thread1, thrd_t __thread2)
> +{
> +  return __thread1 == __thread2;
> +}
> +#endif
> +
> +
> +/* Mutex functions.  */
> +
> +/* Creates a new mutex object with type __TYPE.  If successful the new
> +   object is pointed by __MUTEX.  */
> +extern int mtx_init (mtx_t *__mutex, int __type);
> +
> +/* Block the current thread until the mutex pointed to by __MUTEX is
> +   unlocked.  In that case current thread will not be blocked.  */
> +extern int mtx_lock (mtx_t *__mutex);
> +
> +/* Block the current thread until the mutex pointed by __MUTEX is unlocked
> +   or time pointed by __TIME_POINT is reached.  In case the mutex is unlock,
> +   the current thread will not be blocked.  */
> +extern int mtx_timedlock (mtx_t *__restrict __mutex,
> +			  const struct timespec *__restrict __time_point);
> +
> +/* Try to lock the mutex pointed by __MUTEX without blocking.  If the mutex
> +   is free the current threads takes control of it, otherwise it returns
> +   immediately.  */
> +extern int mtx_trylock (mtx_t *__mutex);
> +
> +/* Unlock the mutex pointed by __MUTEX.  It may potentially awake other
> +   threads waiting on this mutex.  */
> +extern int mtx_unlock (mtx_t *__mutex);
> +
> +/* Destroy the mutex object pointed by __MUTEX.  */
> +extern void mtx_destroy (mtx_t *__mutex);
> +
> +
> +/* Call function __FUNC exactly once, even if invoked from several threads.
> +   All calls must be made with the same __FLAGS object.  */
> +extern void call_once (once_flag *__flag, void (*__func)(void));
> +
> +
> +/* Condition variable functions.  */
> +
> +/* Initialize new condition variable pointed by __COND.  */
> +extern int cnd_init (cnd_t *__cond);
> +
> +/* Unblock one thread that currently waits on condition variable pointed
> +   by __COND.  */
> +extern int cnd_signal (cnd_t *__cond);
> +
> +/* Unblock all threads currently waiting on condition variable pointed by
> +   __COND.  */
> +extern int cnd_broadcast (cnd_t *__cond);
> +
> +/* Block current thread on the condition variable pointed by __COND.  */
> +extern int cnd_wait (cnd_t *__cond, mtx_t *__mutex);
> +
> +/* Block current thread on the condition variable until condition variable
> +   pointed by __COND is signaled or time pointed by __TIME_POINT is
> +   reached.  */
> +extern int cnd_timedwait (cnd_t *__restrict __cond,
> +			  mtx_t *__restrict __mutex,
> +			  const struct timespec *__restrict __time_point);
> +
> +/* Destroy condition variable pointed by __cond and free all of its
> +   resources.  */
> +extern void cnd_destroy (cnd_t *__COND);
> +
> +
> +/* Thread specific storage functions.  */
> +
> +/* Create new thread-specific storage key and stores it in the object pointed
> +   by __TSS_ID.  If __DESTRUCTOR is not NULL, the function will be called when
> +   the thread terminates.  */
> +extern int tss_create (tss_t *__tss_id, tss_dtor_t __destructor);
> +
> +/* Return the value held in thread-specific storage for the current thread
> +   identified by __TSS_ID.  */
> +extern void *tss_get (tss_t __tss_id);
> +
> +/* Sets the value of the thread-specific storage identified by __TSS_ID for
> +   the current thread to __VAL.  */
> +extern int tss_set (tss_t __tss_id, void *__val);
> +
> +/* Destroys the thread-specific storage identified by __TSS_ID.  The
> +   destructor is not called until thrd_exit is called.  */
> +extern void tss_delete (tss_t __tss_id);
> +
> +__END_DECLS
> +
> +#endif /* _THREADS_H */
>