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Re: [PATCH] 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

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 */


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