Require C11 Atomic Operations via <stdatomic.h>

Make the C11 Atomic Operations mandatory and drop the Gcc __atomic builtin shims.
2025-08-30 22:15:20 +00:00 · 2023-01-10 13:06:13 +01:00
parent 1c456c0284
commit baced007af
4 changed files with 37 additions and 198 deletions
--- a/configure.ac
+++ b/configure.ac
@@ -309,12 +309,48 @@ AC_CHECK_HEADERS([fcntl.h regex.h sys/time.h unistd.h sys/mman.h sys/sockio.h sy
 		 ])

 #
-# Check for thread local storage
+# Check for C11 thread local storage
 #
 # NOTE: OpenBSD doesn't ship <threads.h>, so we can't require it (yet).
 #
 AC_CHECK_HEADERS([threads.h])

+#
+# C11 Atomic Operations
+#
+
+AC_CHECK_HEADERS([stdatomic.h],
+		 [],
+		 [AC_MSG_ERROR([C11 Atomic Operations required, update your toolchain to build BIND 9])])
+
+AC_COMPILE_IFELSE(
+  [AC_LANG_PROGRAM(
+     [[#include <stdatomic.h>]],
+     [[atomic_int_fast32_t val = 0; atomic_fetch_add_explicit(&val, 1, memory_order_relaxed);]]
+   )],
+  [AC_MSG_CHECKING([whether -latomic is needed for 64-bit stdatomic.h functions])
+   AC_LINK_IFELSE(
+     [AC_LANG_PROGRAM(
+	[[#include <stdatomic.h>]],
+	[[atomic_int_fast64_t val = 0; atomic_fetch_add_explicit(&val, 1, memory_order_relaxed);]]
+      )],
+     [AC_MSG_RESULT([no])],
+     [LIBS="$LIBS -latomic"
+      AC_LINK_IFELSE(
+	[AC_LANG_PROGRAM(
+	   [[#include <stdatomic.h>]],
+	   [[atomic_int_fast64_t val = 0; atomic_fetch_add_explicit(&val, 1, memory_order_relaxed);]]
+	 )],
+	[AC_MSG_RESULT([yes])],
+	[AC_MSG_FAILURE([libatomic needed, but linking with -latomic failed, please fix your toolchain.])])
+     ])
+  ],
+  [AC_MSG_FAILURE([stdatomic.h header found, but compilation failed, please fix your toolchain.])])
+
+AC_CHECK_HEADERS([stdalign.h stdnoreturn.h],
+		 [],
+		 [AC_MSG_ERROR([C11 standard headers not found, update your toolchain.])])
+
 AC_C_CONST
 AC_C_INLINE
 AC_C_VOLATILE
@@ -1099,73 +1135,6 @@ AC_COMPILE_IFELSE(
 #
 AC_CHECK_FUNCS([if_nametoindex])

-ISC_ATOMIC_LIBS=""
-AC_CHECK_HEADERS(
-  [stdatomic.h],
-  [AC_MSG_CHECKING([for memory model aware atomic operations])
-   AC_COMPILE_IFELSE(
-     [AC_LANG_PROGRAM(
-	[[#include <stdatomic.h>]],
-	[[atomic_int_fast32_t val = 0; atomic_fetch_add_explicit(&val, 1, memory_order_relaxed);]]
-      )],
-     [AC_MSG_RESULT([stdatomic.h])
-      AC_MSG_CHECKING([whether -latomic is needed for 64-bit stdatomic.h functions])
-      AC_LINK_IFELSE(
-	[AC_LANG_PROGRAM(
-	   [[#include <stdatomic.h>]],
-	   [[atomic_int_fast64_t val = 0; atomic_fetch_add_explicit(&val, 1, memory_order_relaxed);]]
-	 )],
-	[AC_MSG_RESULT([no])],
-	[ISC_ATOMIC_LIBS="-latomic"
-	 AX_SAVE_FLAGS([atomic])
-	 LIBS="$LIBS $ISC_ATOMIC_LIBS"
-	 AC_LINK_IFELSE(
-	   [AC_LANG_PROGRAM(
-	      [[#include <stdatomic.h>]],
-	      [[atomic_int_fast64_t val = 0; atomic_fetch_add_explicit(&val, 1, memory_order_relaxed);]]
-	    )],
-	   [AC_MSG_RESULT([yes])],
-	   [AC_MSG_FAILURE([libatomic needed, but linking with -latomic failed, please fix your toolchain.])])
-	 AX_RESTORE_FLAGS([atomic])
-	])
-     ],
-     [AC_MSG_FAILURE([stdatomic.h header found, but compilation failed, please fix your toolchain.])]
-   )],
-  [AC_MSG_CHECKING([for memory model aware atomic operations])
-   AC_COMPILE_IFELSE(
-     [AC_LANG_PROGRAM(
-	[[#include <inttypes.h>]],
-	[[int32_t val = 0; __atomic_fetch_add(&val, 1, __ATOMIC_RELAXED);]]
-      )],
-     [AC_MSG_RESULT([__atomic builtins])
-      AC_DEFINE([HAVE___ATOMIC], [1], [define if __atomic builtins are not available])
-      AC_MSG_CHECKING([whether -latomic is needed for 64-bit __atomic builtins])
-      AC_LINK_IFELSE(
-	[AC_LANG_PROGRAM(
-	   [[#include <inttypes.h>]],
-	   [[int64_t val = 0; __atomic_fetch_add(&val, 1, __ATOMIC_RELAXED);]]
-	 )],
-	[AC_MSG_RESULT([no])],
-	[ISC_ATOMIC_LIBS="-latomic"
-	 AX_SAVE_FLAGS([atomic])
-	 LIBS="$LIBS $ISC_ATOMIC_LIBS"
-	 AC_LINK_IFELSE(
-	   [AC_LANG_PROGRAM(
-	      [[#include <inttypes.h>]],
-	      [[int64_t val = 0; __atomic_fetch_add(&val, 1, __ATOMIC_RELAXED);]]
-	    )],
-	   [AC_MSG_RESULT([yes])],
-	   [AC_MSG_FAILURE([libatomic needed, but linking with -latomic failed, please fix your toolchain.])])
-	 AX_RESTORE_FLAGS([atomic])
-	])
-     ],
-     [AC_MSG_FAILURE([not found])
-     ])
-  ])
-LIBS="$LIBS $ISC_ATOMIC_LIBS"
-
-AC_CHECK_HEADERS([stdalign.h stdnoreturn.h])
-
 AC_CHECK_HEADERS([uchar.h])

 #
--- a/lib/isc/Makefile.am
+++ b/lib/isc/Makefile.am
@@ -86,7 +86,6 @@ libisc_la_HEADERS =			\
 	include/isc/sockaddr.h		\
 	include/isc/stat.h		\
 	include/isc/stats.h		\
-	include/isc/stdatomic.h		\
 	include/isc/stdio.h		\
 	include/isc/stdtime.h		\
 	include/isc/strerr.h		\
--- a/lib/isc/include/isc/atomic.h
+++ b/lib/isc/include/isc/atomic.h
@@ -13,11 +13,7 @@

 #pragma once

-#if __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_ATOMICS__)
 #include <stdatomic.h>
-#else
-#include <isc/stdatomic.h>
-#endif

 #include <isc/util.h>

--- a/lib/isc/include/isc/stdatomic.h
+++ b/lib/isc/include/isc/stdatomic.h
@@ -1,125 +0,0 @@
-/*
- * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
- *
- * SPDX-License-Identifier: MPL-2.0
- *
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, you can obtain one at https://mozilla.org/MPL/2.0/.
- *
- * See the COPYRIGHT file distributed with this work for additional
- * information regarding copyright ownership.
- */
-
-#pragma once
-
-#include <inttypes.h>
-#include <stdbool.h>
-#include <stddef.h>
-#if HAVE_UCHAR_H
-#include <uchar.h>
-#endif /* HAVE_UCHAR_H */
-
-/* GCC 4.7.0 introduced __atomic builtins, but not the __GNUC_ATOMICS define */
-#if !defined(__GNUC_ATOMICS) && __GNUC__ == 4 && __GNUC_MINOR__ >= 7
-#define __GNUC_ATOMICS
-#endif
-
-#if !defined(__GNUC_ATOMICS)
-#error "isc/stdatomic.h does not support your compiler"
-#endif /* if !defined(__GNUC_ATOMICS) */
-
-typedef enum memory_order {
-	memory_order_relaxed = __ATOMIC_RELAXED,
-	memory_order_consume = __ATOMIC_CONSUME,
-	memory_order_acquire = __ATOMIC_ACQUIRE,
-	memory_order_release = __ATOMIC_RELEASE,
-	memory_order_acq_rel = __ATOMIC_ACQ_REL,
-	memory_order_seq_cst = __ATOMIC_SEQ_CST
-} memory_order;
-
-#ifndef HAVE_UCHAR_H
-typedef uint_least16_t char16_t;
-typedef uint_least32_t char32_t;
-#endif /* HAVE_UCHAR_H */
-
-typedef bool		   atomic_bool;
-typedef char		   atomic_char;
-typedef signed char	   atomic_schar;
-typedef unsigned char	   atomic_uchar;
-typedef short		   atomic_short;
-typedef unsigned short	   atomic_ushort;
-typedef int		   atomic_int;
-typedef unsigned int	   atomic_uint;
-typedef long		   atomic_long;
-typedef unsigned long	   atomic_ulong;
-typedef long long	   atomic_llong;
-typedef unsigned long long atomic_ullong;
-typedef char16_t	   atomic_char16_t;
-typedef char32_t	   atomic_char32_t;
-typedef wchar_t		   atomic_wchar_t;
-typedef int_least8_t	   atomic_int_least8_t;
-typedef uint_least8_t	   atomic_uint_least8_t;
-typedef int_least16_t	   atomic_int_least16_t;
-typedef uint_least16_t	   atomic_uint_least16_t;
-typedef int_least32_t	   atomic_int_least32_t;
-typedef uint_least32_t	   atomic_uint_least32_t;
-typedef int_least64_t	   atomic_int_least64_t;
-typedef uint_least64_t	   atomic_uint_least64_t;
-typedef int_fast8_t	   atomic_int_fast8_t;
-typedef uint_fast8_t	   atomic_uint_fast8_t;
-typedef int_fast16_t	   atomic_int_fast16_t;
-typedef uint_fast16_t	   atomic_uint_fast16_t;
-typedef int_fast32_t	   atomic_int_fast32_t;
-typedef uint_fast32_t	   atomic_uint_fast32_t;
-typedef int_fast64_t	   atomic_int_fast64_t;
-typedef uint_fast64_t	   atomic_uint_fast64_t;
-typedef intptr_t	   atomic_intptr_t;
-typedef uintptr_t	   atomic_uintptr_t;
-typedef size_t		   atomic_size_t;
-typedef ptrdiff_t	   atomic_ptrdiff_t;
-typedef intmax_t	   atomic_intmax_t;
-typedef uintmax_t	   atomic_uintmax_t;
-
-#define atomic_init(obj, desired)	 (*obj = desired)
-#define atomic_load_explicit(obj, order) __atomic_load_n(obj, order)
-#define atomic_store_explicit(obj, desired, order) \
-	__atomic_store_n(obj, desired, order)
-#define atomic_fetch_add_explicit(obj, arg, order) \
-	__atomic_fetch_add(obj, arg, order)
-#define atomic_fetch_sub_explicit(obj, arg, order) \
-	__atomic_fetch_sub(obj, arg, order)
-#define atomic_fetch_and_explicit(obj, arg, order) \
-	__atomic_fetch_and(obj, arg, order)
-#define atomic_fetch_or_explicit(obj, arg, order) \
-	__atomic_fetch_or(obj, arg, order)
-#define atomic_compare_exchange_strong_explicit(obj, expected, desired, succ, \
-						fail)                         \
-	__atomic_compare_exchange_n(obj, expected, desired, 0, succ, fail)
-#define atomic_compare_exchange_weak_explicit(obj, expected, desired, succ, \
-					      fail)                         \
-	__atomic_compare_exchange_n(obj, expected, desired, 1, succ, fail)
-#define atomic_exchange_explicit(obj, desired, order) \
-	__atomic_exchange_n(obj, desired, order)
-
-#define atomic_load(obj) atomic_load_explicit(obj, memory_order_seq_cst)
-#define atomic_store(obj, arg) \
-	atomic_store_explicit(obj, arg, memory_order_seq_cst)
-#define atomic_fetch_add(obj, arg) \
-	atomic_fetch_add_explicit(obj, arg, memory_order_seq_cst)
-#define atomic_fetch_sub(obj, arg) \
-	atomic_fetch_sub_explicit(obj, arg, memory_order_seq_cst)
-#define atomic_fetch_and(obj, arg) \
-	atomic_fetch_and_explicit(obj, arg, memory_order_seq_cst)
-#define atomic_fetch_or(obj, arg) \
-	atomic_fetch_or_explicit(obj, arg, memory_order_seq_cst)
-#define atomic_compare_exchange_strong(obj, expected, desired)          \
-	atomic_compare_exchange_strong_explicit(obj, expected, desired, \
-						memory_order_seq_cst,   \
-						memory_order_seq_cst)
-#define atomic_compare_exchange_weak(obj, expected, desired)          \
-	atomic_compare_exchange_weak_explicit(obj, expected, desired, \
-					      memory_order_seq_cst,   \
-					      memory_order_seq_cst)
-#define atomic_exchange(obj, desired) \
-	atomic_exchange_explicit(obj, desired, memory_order_seq_cst)