From owner-svn-src-all@FreeBSD.ORG Wed Sep 26 19:49:23 2012 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 96D30106564A; Wed, 26 Sep 2012 19:49:23 +0000 (UTC) (envelope-from tijl@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 774598FC0A; Wed, 26 Sep 2012 19:49:23 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.4/8.14.4) with ESMTP id q8QJnNnr082764; Wed, 26 Sep 2012 19:49:23 GMT (envelope-from tijl@svn.freebsd.org) Received: (from tijl@localhost) by svn.freebsd.org (8.14.4/8.14.4/Submit) id q8QJnN95082762; Wed, 26 Sep 2012 19:49:23 GMT (envelope-from tijl@svn.freebsd.org) Message-Id: <201209261949.q8QJnN95082762@svn.freebsd.org> From: Tijl Coosemans Date: Wed, 26 Sep 2012 19:49:23 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r240970 - head/include X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Sep 2012 19:49:23 -0000 Author: tijl Date: Wed Sep 26 19:49:22 2012 New Revision: 240970 URL: http://svn.freebsd.org/changeset/base/240970 Log: - Make C11 atomic macros usable in expressions: - Replace do-while statements with void expressions. - Wrap __asm statements in statement expressions. - Make the macros function-like: - Evaluate all arguments exactly once. - Make sure there's a sequence point between evaluation of the arguments and the function body. Arguments should be evaluated before any memory barriers. - Fix use of __atomic_is_lock_free built-in. It requires the address of an atomic variable as second argument. Use this built-in on clang as well because clang's __c11_atomic_is_lock_free only takes the size of the variable into account. - In atomic_exchange_explicit put the barrier before instead of after the __sync_lock_test_and_set call. Reviewed by: theraven Modified: head/include/stdatomic.h Modified: head/include/stdatomic.h ============================================================================== --- head/include/stdatomic.h Wed Sep 26 18:59:20 2012 (r240969) +++ head/include/stdatomic.h Wed Sep 26 19:49:22 2012 (r240970) @@ -54,9 +54,7 @@ #define atomic_init(obj, value) __c11_atomic_init(obj, value) #else #define ATOMIC_VAR_INIT(value) { .__val = (value) } -#define atomic_init(obj, value) do { \ - (obj)->__val = (value); \ -} while (0) +#define atomic_init(obj, value) ((void)((obj)->__val = (value))) #endif /* @@ -111,23 +109,24 @@ enum memory_order { #define atomic_thread_fence(order) __atomic_thread_fence(order) #define atomic_signal_fence(order) __atomic_signal_fence(order) #else -#define atomic_thread_fence(order) __sync_synchronize() -#define atomic_signal_fence(order) __asm volatile ("" : : : "memory") +#define atomic_thread_fence(order) ((void)(order), __sync_synchronize()) +#define atomic_signal_fence(order) __extension__ ({ \ + (void)(order); \ + __asm volatile ("" ::: "memory"); \ + (void)0; \ +}) #endif /* * 7.17.5 Lock-free property. */ -#if defined(__CLANG_ATOMICS) -#define atomic_is_lock_free(obj) \ - __c11_atomic_is_lock_free(sizeof(obj)) -#elif defined(__GNUC_ATOMICS) +#if defined(__CLANG_ATOMICS) || defined(__GNUC_ATOMICS) #define atomic_is_lock_free(obj) \ - __atomic_is_lock_free(sizeof((obj)->__val)) + __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->val) #else #define atomic_is_lock_free(obj) \ - (sizeof((obj)->__val) <= sizeof(void *)) + ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) #endif /* @@ -234,13 +233,17 @@ typedef _Atomic(__uintmax_t) atomic_uin __atomic_store_n(&(object)->__val, desired, order) #else #define atomic_compare_exchange_strong_explicit(object, expected, \ - desired, success, failure) ({ \ + desired, success, failure) __extension__ ({ \ __typeof__((object)->__val) __v; \ + __typeof__(expected) __e; \ _Bool __r; \ + __e = (expected); \ + (void)(success); \ + (void)(failure); \ __v = __sync_val_compare_and_swap(&(object)->__val, \ - *(expected), desired); \ - __r = *(expected) == __v; \ - *(expected) = __v; \ + *__e, (desired)); \ + __r = (*__e == __v); \ + *__e = __v; \ __r; \ }) @@ -250,19 +253,21 @@ typedef _Atomic(__uintmax_t) atomic_uin desired, success, failure) #if __has_builtin(__sync_swap) /* Clang provides a full-barrier atomic exchange - use it if available. */ -#define atomic_exchange_explicit(object, desired, order) \ - __sync_swap(&(object)->__val, desired) +#define atomic_exchange_explicit(object, desired, order) \ + ((void)(order), __sync_swap(&(object)->__val, desired)) #else /* * __sync_lock_test_and_set() is only an acquire barrier in theory (although in - * practice it is usually a full barrier) so we need an explicit barrier after + * practice it is usually a full barrier) so we need an explicit barrier before * it. */ -#define atomic_exchange_explicit(object, desired, order) ({ \ - __typeof__((object)->__val) __v; \ - __v = __sync_lock_test_and_set(&(object)->__val, desired); \ +#define atomic_exchange_explicit(object, desired, order) \ +__extension__ ({ \ + __typeof__(object) __o = (object); \ + __typeof__(desired) __d = (desired); \ + (void)(order); \ __sync_synchronize(); \ - __v; \ + __sync_lock_test_and_set(&(__o)->__val, __d); \ }) #endif #define atomic_fetch_add_explicit(object, operand, order) \ @@ -277,11 +282,14 @@ typedef _Atomic(__uintmax_t) atomic_uin __sync_fetch_and_xor(&(object)->__val, operand) #define atomic_load_explicit(object, order) \ __sync_fetch_and_add(&(object)->__val, 0) -#define atomic_store_explicit(object, desired, order) do { \ +#define atomic_store_explicit(object, desired, order) __extension__ ({ \ + __typeof__(object) __o = (object); \ + __typeof__(desired) __d = (desired); \ + (void)(order); \ __sync_synchronize(); \ - (object)->__val = (desired); \ + __o->__val = __d; \ __sync_synchronize(); \ -} while (0) +}) #endif /*