Merge pull request #62 from jcowgill/atomics-cleanup

Atomics cleanup

config/Makefile.am

@@ -1,7 +1,7 @@
 # We don't actually build anything in the `cpu' and `os'
 # subdirectories.
 
-DIST_SUBDIRS = cpu os sysdeps
+DIST_SUBDIRS = os sysdeps
 
 EXTRA_DIST = depcomp
 MAINTAINERCLEANFILES = Makefile.in config.guess config.sub \

config/cpu/Makefile.am

@@ -1,2 +0,0 @@
-MAINTAINERCLEANFILES = Makefile.in
-DIST_SUBDIRS = generic i386 powerpc

config/cpu/generic/Makefile.am

@@ -1,3 +0,0 @@
-MAINTAINERCLEANFILES = Makefile.in
-noinst_HEADERS = atomicity.h
-

config/cpu/generic/atomicity.h

@@ -1,39 +0,0 @@
-/* Low-level functions for atomic operations.  Stub version.
-   Copyright (C) 1997,2001 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, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
-
-#ifndef _ATOMICITY_H
-#define _ATOMICITY_H    1
-
-typedef int _Atomic_word;
-
-static inline _Atomic_word
-__attribute__ ((__unused__))
-__exchange_and_add (volatile _Atomic_word* mem, int val)
-{
-	return __sync_fetch_and_add (mem, val);
-}
-
-static inline void
-__attribute__ ((__unused__))
-__atomic_add (volatile _Atomic_word* mem, int val)
-{
-	__sync_add_and_fetch (mem, val);
-}
-
-#endif /* atomicity.h */

config/cpu/i386/Makefile.am

@@ -1,3 +0,0 @@
-MAINTAINERCLEANFILES = Makefile.in
-noinst_HEADERS = atomicity.h
-

config/cpu/i386/atomicity.h

@@ -1,53 +0,0 @@
-// Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 2, or (at your option)
-// any later version.
-
-// This 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 General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING.  If not, write to the Free
-// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
-// USA.
-
-// As a special exception, you may use this file as part of a free software
-// library without restriction.  Specifically, if other files instantiate
-// templates or use macros or inline functions from this file, or you compile
-// this file and link it with other files to produce an executable, this
-// file does not by itself cause the resulting executable to be covered by
-// the GNU General Public License.  This exception does not however
-// invalidate any other reasons why the executable file might be covered by
-// the GNU General Public License.
-
-#ifndef _GLIBCXX_ATOMICITY_H
-#define _GLIBCXX_ATOMICITY_H    1
-
-typedef int _Atomic_word;
-
-static inline _Atomic_word
-__attribute__ ((__unused__))
-__exchange_and_add (volatile _Atomic_word* __mem, int __val)
-{
-	register _Atomic_word __result;
-
-	__asm__ __volatile__ ("lock; xaddl %0,%1"
-			      : "=r" (__result), "=m" (*__mem)
-			      : "0" (__val), "m" (*__mem));
-	return __result;
-}
-
-static inline void
-__attribute__ ((__unused__))
-__atomic_add (volatile _Atomic_word* __mem, int __val)
-{
-	__asm__ __volatile__ ("lock; addl %1,%0"
-			      : "=m" (*__mem) : "ir" (__val), "m" (*__mem));
-}
-
-#endif /* atomicity.h */

config/cpu/powerpc/Makefile.am

@@ -1,3 +0,0 @@
-MAINTAINERCLEANFILES = Makefile.in
-noinst_HEADERS = atomicity.h
-

config/cpu/powerpc/atomicity.h

@@ -1,80 +0,0 @@
-// Low-level functions for atomic operations: PowerPC version  -*- C++ -*-
-
-// Copyright (C) 1999, 2000, 2001, 2003 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 2, or (at your option)
-// any later version.
-
-// This 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 General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING.  If not, write to the Free
-// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
-// USA.
-
-// As a special exception, you may use this file as part of a free software
-// library without restriction.  Specifically, if other files instantiate
-// templates or use macros or inline functions from this file, or you compile
-// this file and link it with other files to produce an executable, this
-// file does not by itself cause the resulting executable to be covered by
-// the GNU General Public License.  This exception does not however
-// invalidate any other reasons why the executable file might be covered by
-// the GNU General Public License.
-
-#ifndef _GLIBCXX_ATOMICITY_H
-#define _GLIBCXX_ATOMICITY_H    1
-
-#ifdef __PPC405__
-#define _STWCX "sync \n\tstwcx. "
-#else
-#define _STWCX "stwcx. "
-#endif
-
-typedef int _Atomic_word;
-
-static inline _Atomic_word
-__attribute__ ((__unused__))
-__exchange_and_add (volatile _Atomic_word* __mem, int __val)
-{
-	_Atomic_word __tmp, __res;
-
-	__asm__ __volatile__ (
-		"/* Inline exchange & add */\n"
-		"0:\t"
-		"lwarx    %0,0,%3 \n\t"
-		"add%I4   %1,%0,%4 \n\t"
-		_STWCX "  %1,0,%3 \n\t"
-		"bne-     0b \n\t"
-		"/* End exchange & add */"
-		: "=&b" (__res), "=&r" (__tmp), "=m" (*__mem)
-		: "r" (__mem), "Ir" (__val), "m" (*__mem)
-		: "cr0");
-	return __res;
-}
-
-static inline void
-__attribute__ ((__unused__))
-__atomic_add (volatile _Atomic_word* __mem, int __val)
-{
-	_Atomic_word __tmp;
-
-	__asm__ __volatile__ (
-		"/* Inline atomic add */\n"
-		"0:\t"
-		"lwarx    %0,0,%2 \n\t"
-		"add%I3   %0,%0,%3 \n\t"
-		_STWCX "  %0,0,%2 \n\t"
-		"bne-     0b \n\t"
-		"/* End atomic add */"
-		: "=&b" (__tmp), "=m" (*__mem)
-		: "r" (__mem), "Ir" (__val), "m" (*__mem)
-		: "cr0");
-}
-
-#endif /* atomicity.h */

config/sysdeps/Makefile.am

@@ -7,7 +7,6 @@ MAINTAINERCLEANFILES = Makefile.in
 noinst_HEADERS =		\
         systemtest.c            \
         sanitycheck.c           \
-	atomicity.h		\
 	getopt.h		\
 	ipc.h			\
 	mach_port.h		\

config/sysdeps/atomicity.h

@@ -1,24 +0,0 @@
-#ifndef _jack_sysdep_atomicity_h_
-#define _jack_sysdep_atomicity_h_
-
-#if defined(__i386__)
-
-#include <config/cpu/i386/atomicity.h>
-
-#elif defined(__x86_64)
-
-/* x86_64 can use rdtsc just like i[456]86 */
-
-#include <config/cpu/i386/atomicity.h>
-
-#elif defined(__powerpc__) || defined(__ppc__) /* linux and OSX use different tokens */
-
-#include <config/cpu/powerpc/atomicity.h>
-
-#else
-
-#include <config/cpu/generic/atomicity.h>
-
-#endif  /* processor selection */
-
-#endif  /* _jack_sysdep_atomicity_h_ */

configure.ac

@@ -964,10 +964,6 @@ AM_CONDITIONAL(HAVE_ZITA_BRIDGE_DEPS, $HAVE_ZITA_BRIDGE_DEPS)
 AC_OUTPUT(
 Makefile
 config/Makefile
-config/cpu/Makefile
-config/cpu/generic/Makefile
-config/cpu/i386/Makefile
-config/cpu/powerpc/Makefile
 config/os/Makefile
 config/os/generic/Makefile
 config/os/gnu-linux/Makefile

doc/porting.dox

@@ -88,25 +88,6 @@ Be sure to place any generic implementation alternative in the @c
 \#else or use an @c \#ifndef, so no other code needs to know your
 conditional labels.
 
-@section portcpu Processor Dependencies
-
-JACK uses some low-level machine operations for thread-safe updates to
-shared memory.  A low-level implementation of @c <sysdeps/atomicity.h>
-is provided for every target processor architecture.  There is also a
-generic implementation using POSIX spin locks, but that is not a good
-enough solution for serious use.
-
-The GCC package provides versions that work on most modern hardware.
-We've tried to keep things as close to the original as possible, while
-removing a bunch of os-specific files that didn't seem relevant.  A
-primary goal has been to avoid changing the CPU-dependent @c
-<sysdeps/atomicity.h> headers.
-
-The relevant GCC documentation provides some helpful background,
-especially the @c atomicity.h discussion at
-<http://gcc.gnu.org/onlinedocs/porting/Thread-safety.html>.
-
-
 @section portissues Issues Not Addressed
 
   - Cross-compilation has not been tested, or even thought through in

include/atomicity.h

@@ -20,19 +20,26 @@
 #ifndef __jack_atomicity_h__
 #define __jack_atomicity_h__
 
-/*
- * Interface with various machine-dependent headers derived from the
- * gcc/libstdc++.v3 sources.  We try to modify the GCC sources as
- * little as possible.  The following include is resolved using the
- * config/configure.hosts mechanism.  It will use an OS-dependent
- * version if available, otherwise the one for this CPU.  Some of
- * these files might not work with older GCC compilers.
- */
-#include <sysdeps/atomicity.h>
+#if __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_ATOMICS__)
+
+#include <stdatomic.h>
+
+typedef atomic_int _Atomic_word;
+
+static inline int exchange_and_add(volatile _Atomic_word* obj, int value)
+{
+    return atomic_fetch_add_explicit(obj, value, memory_order_relaxed);
+}
+
+#else
+
+typedef int _Atomic_word;
+
+static inline int exchange_and_add(volatile _Atomic_word* obj, int value)
+{
+    return __atomic_fetch_add(obj, value, __ATOMIC_RELAXED);
+}
 
-/* These functions are defined for each platform.  The C++ library
- * function names start with "__" to avoid namespace pollution. */
-#define exchange_and_add __exchange_and_add
-#define atomic_add __atomic_add
+#endif
 
 #endif /* __jack_atomicity_h__ */

include/internal.h

@@ -60,7 +60,7 @@ void jack_set_clock_source (jack_timer_type_t);
 const char* jack_clock_source_name (jack_timer_type_t);
 
 #include <sysdeps/time.h>
-#include <sysdeps/atomicity.h>
+#include "atomicity.h"
 
 #ifdef JACK_USE_MACH_THREADS
 #include <sysdeps/mach_port.h>

libjack/messagebuffer.c

@@ -161,7 +161,7 @@ jack_messagebuffer_add (const char *fmt, ...)
 		pthread_cond_signal (&mb_ready_cond);
 		pthread_mutex_unlock (&mb_write_lock);
 	} else {                        /* lock collision */
-		atomic_add (&mb_overruns, 1);
+		exchange_and_add (&mb_overruns, 1);
 	}
 }