Re: [PATCH] Remove __PTHREAD_MUTEX_HAVE_ELISION undefined warning

[Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>]

On 26-03-2014 13:36, Roland McGrath wrote:
>> +#if !defined _PTHREAD_H
> This is OK but there is no reason not to use #ifndef.
>
>> +# error "Never include this file directly. Use <pthread.h> instead"
> Two spaces between the sentences, and a period at the end of each.
>
> (Those two also apply to the sysdeps variant files you're adding, of course.)
>
>> +#define __PTHREAD_MUTEX_HAVE_ELISION 0
> As Joseph also requested, add an explanatory comment describing the
> protocol for this macro and how other sysdeps variant files might define
> it.
>
>> +#endif
>> diff --git a/nptl/sysdeps/pthread/pthread.h b/nptl/sysdeps/pthread/pthread.h
>> index 1e0c5dc..39d6b91 100644
>> --- a/nptl/sysdeps/pthread/pthread.h
>> +++ b/nptl/sysdeps/pthread/pthread.h
>> @@ -26,6 +26,7 @@
>>  #include <bits/pthreadtypes.h>
>>  #include <bits/setjmp.h>
>>  #include <bits/wordsize.h>
>> +#include <bits/pthread-elision.h>
> I'd put it right after bits/pthreadtypes.h.
>
>> --- a/posix/Makefile
>> +++ b/posix/Makefile
>> @@ -29,7 +29,7 @@ headers	:= sys/utsname.h sys/times.h sys/wait.h sys/types.h unistd.h	      \
>>  	   bits/local_lim.h tar.h bits/utsname.h bits/confname.h	      \
>>  	   bits/waitflags.h bits/waitstatus.h sys/unistd.h sched.h	      \
>>  	   bits/sched.h re_comp.h wait.h bits/environments.h cpio.h	      \
>> -	   sys/sysmacros.h spawn.h bits/unistd.h
>> +	   sys/sysmacros.h spawn.h bits/unistd.h bits/pthread-elision.h
> That belongs in nptl/Makefile.
>
>
> Thanks,
> Roland
>
Thanks for the review, what about this version (fixed all the comments):

--

	* nptl/sysdeps/pthread/bits/pthread-elision.h: New header: define
	default lock elision support and defines.
	* nptl/sysdeps/pthread/pthread.h: Include pthread-elision.h.
	* nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
	(__PTHREAD_MUTEX_HAVE_ELISION): Undefine.
	* nptl/sysdeps/unix/sysv/linux/x86/bits/pthread-elision.h: New
	header: x86 specific lock elision support.
	* nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h:
	(__PTHREAD_MUTEX_HAVE_ELISION): Definition moved to specific lock
	elision header.
	* nptl/Makefile: Add bits/pthread-elision.h to install.

---

diff --git a/nptl/Makefile b/nptl/Makefile
index 897ac96..2c79023 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -22,7 +22,7 @@ subdir	:= nptl
 
 include ../Makeconfig
 
-headers := pthread.h semaphore.h bits/semaphore.h
+headers := pthread.h semaphore.h bits/semaphore.h bits/pthread-elision.h
 
 extra-libs := libpthread
 extra-libs-others := $(extra-libs)
diff --git a/nptl/sysdeps/pthread/bits/pthread-elision.h b/nptl/sysdeps/pthread/bits/pthread-elision.h
new file mode 100644
index 0000000..c2ea989
--- /dev/null
+++ b/nptl/sysdeps/pthread/bits/pthread-elision.h
@@ -0,0 +1,34 @@
+/* Lock elision default definitions.
+   Copyright (C) 2014 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 _PTHREAD_ELISION_H
+#define _PTHREAD_ELISION_H	1
+
+#ifndef _PTHREAD_H
+# error "Never include this file directly.  Use <pthread.h> instead"
+#endif
+
+/* Define it if the architecture supports lock elision using transactional
+   memory or a similar facility.  It changes the mutex initializers to add
+   the required elision fields.  Currently, three value are possible:
+   * 0: No elision support, default value.
+   * 1: Elision support for 64 bits.
+   * 2: Elision support for 32 bits.  */
+#define __PTHREAD_MUTEX_HAVE_ELISION 0
+
+#endif
diff --git a/nptl/sysdeps/pthread/pthread.h b/nptl/sysdeps/pthread/pthread.h
index 1e0c5dc..47e42c6 100644
--- a/nptl/sysdeps/pthread/pthread.h
+++ b/nptl/sysdeps/pthread/pthread.h
@@ -24,6 +24,7 @@
 #include <time.h>
 
 #include <bits/pthreadtypes.h>
+#include <bits/pthread-elision.h>
 #include <bits/setjmp.h>
 #include <bits/wordsize.h>
 
diff --git a/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
index 23a1698..a361db6 100644
--- a/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/s390/bits/pthreadtypes.h
@@ -20,8 +20,6 @@
 
 #include <bits/wordsize.h>
 
-# define __PTHREAD_MUTEX_HAVE_ELISION   0
-
 #if __WORDSIZE == 64
 # define __SIZEOF_PTHREAD_ATTR_T 56
 # define __SIZEOF_PTHREAD_MUTEX_T 40
diff --git a/nptl/sysdeps/unix/sysv/linux/x86/bits/pthread-elision.h b/nptl/sysdeps/unix/sysv/linux/x86/bits/pthread-elision.h
new file mode 100644
index 0000000..3ab29c4
--- /dev/null
+++ b/nptl/sysdeps/unix/sysv/linux/x86/bits/pthread-elision.h
@@ -0,0 +1,32 @@
+/* x86 lock elision definitions.
+   Copyright (C) 2014 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 _PTHREAD_ELISION_H
+#define _PTHREAD_ELISION_H	1
+
+#ifndef _PTHREAD_H
+# error "Never include this file directly.  Use <pthread.h> instead"
+#endif
+
+#ifdef __x86_64__
+# define __PTHREAD_MUTEX_HAVE_ELISION   1
+#else
+# define __PTHREAD_MUTEX_HAVE_ELISION   2
+#endif
+
+#endif
diff --git a/nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h b/nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h
index 28e5144..a5363ec 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h
+++ b/nptl/sysdeps/unix/sysv/linux/x86/bits/pthreadtypes.h
@@ -105,7 +105,6 @@ typedef union
     short __elision;
     __pthread_list_t __list;
 # define __PTHREAD_MUTEX_HAVE_PREV	1
-# define __PTHREAD_MUTEX_HAVE_ELISION   1
 #else
     unsigned int __nusers;
     __extension__ union
@@ -116,7 +115,6 @@ typedef union
 	short __elision;
 # define __spins d.__espins
 # define __elision d.__elision
-# define __PTHREAD_MUTEX_HAVE_ELISION   2
       } d;
       __pthread_slist_t __list;
     };