Author: jhb Date: Mon Aug 6 23:51:08 2018 New Revision: 337399 URL: https://svnweb.freebsd.org/changeset/base/337399
Log: Make the system C11 atomics headers fully compatible with external GCC. The <sys/cdefs.h> and <stdatomic.h> headers already included support for C11 atomics via intrinsincs in modern versions of GCC, but these versions tried to "hide" atomic variables inside a wrapper structure. This wrapper is not compatible with GCC's internal <stdatomic.h> header, so that if GCC's <stdatomic.h> was used together with <sys/cdefs.h>, use of C11 atomics would fail to compile. Fix this by not hiding atomic variables in a structure for modern versions of GCC. The headers already avoid using a wrapper structure on clang. Note that this wrapper was only used if C11 was not enabled (e.g. via -std=c99), so this also fixes compile failures if a modern version of GCC was used with -std=c11 but with FreeBSD's <stdatomic.h> instead of GCC's <stdatomic.h> and this change fixes that case as well. Reported by: Mark Millard Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D16585 Modified: head/sys/sys/cdefs.h head/sys/sys/stdatomic.h Modified: head/sys/sys/cdefs.h ============================================================================== --- head/sys/sys/cdefs.h Mon Aug 6 23:21:13 2018 (r337398) +++ head/sys/sys/cdefs.h Mon Aug 6 23:51:08 2018 (r337399) @@ -268,7 +268,7 @@ #endif #if !defined(__cplusplus) && !__has_extension(c_atomic) && \ - !__has_extension(cxx_atomic) + !__has_extension(cxx_atomic) && !__GNUC_PREREQ__(4, 7) /* * No native support for _Atomic(). Place object in structure to prevent * most forms of direct non-atomic access. Modified: head/sys/sys/stdatomic.h ============================================================================== --- head/sys/sys/stdatomic.h Mon Aug 6 23:21:13 2018 (r337398) +++ head/sys/sys/stdatomic.h Mon Aug 6 23:51:08 2018 (r337399) @@ -171,12 +171,9 @@ atomic_signal_fence(memory_order __order __unused) /* Atomics in kernelspace are always lock-free. */ #define atomic_is_lock_free(obj) \ ((void)(obj), (_Bool)1) -#elif defined(__CLANG_ATOMICS) +#elif defined(__CLANG_ATOMICS) || defined(__GNUC_ATOMICS) #define atomic_is_lock_free(obj) \ __atomic_is_lock_free(sizeof(*(obj)), obj) -#elif defined(__GNUC_ATOMICS) -#define atomic_is_lock_free(obj) \ - __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val) #else #define atomic_is_lock_free(obj) \ ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) @@ -260,28 +257,28 @@ typedef _Atomic(__uintmax_t) atomic_uintmax_t; #elif defined(__GNUC_ATOMICS) #define atomic_compare_exchange_strong_explicit(object, expected, \ desired, success, failure) \ - __atomic_compare_exchange_n(&(object)->__val, expected, \ + __atomic_compare_exchange_n(object, expected, \ desired, 0, success, failure) #define atomic_compare_exchange_weak_explicit(object, expected, \ desired, success, failure) \ - __atomic_compare_exchange_n(&(object)->__val, expected, \ + __atomic_compare_exchange_n(object, expected, \ desired, 1, success, failure) #define atomic_exchange_explicit(object, desired, order) \ - __atomic_exchange_n(&(object)->__val, desired, order) + __atomic_exchange_n(object, desired, order) #define atomic_fetch_add_explicit(object, operand, order) \ - __atomic_fetch_add(&(object)->__val, operand, order) + __atomic_fetch_add(object, operand, order) #define atomic_fetch_and_explicit(object, operand, order) \ - __atomic_fetch_and(&(object)->__val, operand, order) + __atomic_fetch_and(object, operand, order) #define atomic_fetch_or_explicit(object, operand, order) \ - __atomic_fetch_or(&(object)->__val, operand, order) + __atomic_fetch_or(object, operand, order) #define atomic_fetch_sub_explicit(object, operand, order) \ - __atomic_fetch_sub(&(object)->__val, operand, order) + __atomic_fetch_sub(object, operand, order) #define atomic_fetch_xor_explicit(object, operand, order) \ - __atomic_fetch_xor(&(object)->__val, operand, order) + __atomic_fetch_xor(object, operand, order) #define atomic_load_explicit(object, order) \ - __atomic_load_n(&(object)->__val, order) + __atomic_load_n(object, order) #define atomic_store_explicit(object, desired, order) \ - __atomic_store_n(&(object)->__val, desired, order) + __atomic_store_n(object, desired, order) #else #define __atomic_apply_stride(object, operand) \ (((__typeof__((object)->__val))0) + (operand)) _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
