Remove __PTHREAD_MUTEX_HAVE_ELISION undefined warning
Commit Message
This is a respin of the original attempt of remove __PTHREAD_MUTEX_HAVE_ELISION
compile warnings on arch that does not define it. Following Joseph suggestion
I changed to use a bits header.
This patch adds new installed header bits/pthread-elision.h that defines
__PTHREAD_MUTEX_HAVE_ELISION to an appropriated value depending of the
architecture support.
Tested on PPC64 (no warnings) and x86_64 (with --lock-elision=yes/no). On X86_64
I don't have a TM capable chip, however the defines by checking the -E output
is as expected. I didn't check the s390 build, however since it also does not
define __PTHREAD_MUTEX_HAVE_ELISION I expect to follow PPC64 way.
--
* 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.
* posix/Makefile: Add bits/pthread-elision.h to install.
---
Comments
On Wed, 26 Mar 2014, Adhemerval Zanella wrote:
> +#define __PTHREAD_MUTEX_HAVE_ELISION 0
I think the default file should have a comment explaining what the
semantics of the possible values for this macro (0, 1 and 2) are.
> On Wed, 26 Mar 2014, Adhemerval Zanella wrote:
>
> > +#define __PTHREAD_MUTEX_HAVE_ELISION 0
>
> I think the default file should have a comment explaining what the
> semantics of the possible values for this macro (0, 1 and 2) are.
Absolutely. This is a general rule for any sysdeps/generic or similar file
that sets the terms of what identifiers sysdeps variants are required to
define and what their definitions mean.
> +#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
new file mode 100644
@@ -0,0 +1,28 @@
+/* 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
+
+#if !defined _PTHREAD_H
+# error "Never include this file directly. Use <pthread.h> instead"
+#endif
+
+#define __PTHREAD_MUTEX_HAVE_ELISION 0
+
+#endif
@@ -26,6 +26,7 @@
#include <bits/pthreadtypes.h>
#include <bits/setjmp.h>
#include <bits/wordsize.h>
+#include <bits/pthread-elision.h>
/* Detach state. */
@@ -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
new file mode 100644
@@ -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
+
+#if !defined _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
@@ -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;
};
@@ -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
routines := \
uname \