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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 12:24:36 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 12:24:36 +0000
commit06eaf7232e9a920468c0f8d74dcf2fe8b555501c (patch)
treee2c7b5777f728320e5b5542b6213fd3591ba51e2 /include/my_atomic.h
parentInitial commit. (diff)
downloadmariadb-06eaf7232e9a920468c0f8d74dcf2fe8b555501c.tar.xz
mariadb-06eaf7232e9a920468c0f8d74dcf2fe8b555501c.zip
Adding upstream version 1:10.11.6.upstream/1%10.11.6
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+#ifndef MY_ATOMIC_INCLUDED
+#define MY_ATOMIC_INCLUDED
+
+/* Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
+ Copyright (c) 2018, 2022, MariaDB
+
+ This program 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; version 2 of the License.
+
+ This program 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 program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
+
+/*
+ This header defines five atomic operations:
+
+ my_atomic_add#(&var, what)
+ my_atomic_add#_explicit(&var, what, memory_order)
+ 'Fetch and Add'
+ add 'what' to *var, and return the old value of *var
+ All memory orders are valid.
+
+ my_atomic_fas#(&var, what)
+ my_atomic_fas#_explicit(&var, what, memory_order)
+ 'Fetch And Store'
+ store 'what' in *var, and return the old value of *var
+ All memory orders are valid.
+
+ my_atomic_cas#(&var, &old, new)
+ my_atomic_cas#_weak_explicit(&var, &old, new, succ, fail)
+ my_atomic_cas#_strong_explicit(&var, &old, new, succ, fail)
+ 'Compare And Swap'
+ if *var is equal to *old, then store 'new' in *var, and return TRUE
+ otherwise store *var in *old, and return FALSE
+ succ - the memory synchronization ordering for the read-modify-write
+ operation if the comparison succeeds. All memory orders are valid.
+ fail - the memory synchronization ordering for the load operation if the
+ comparison fails. Cannot be MY_MEMORY_ORDER_RELEASE or
+ MY_MEMORY_ORDER_ACQ_REL and cannot specify stronger ordering than succ.
+
+ The weak form is allowed to fail spuriously, that is, act as if *var != *old
+ even if they are equal. When a compare-and-exchange is in a loop, the weak
+ version will yield better performance on some platforms. When a weak
+ compare-and-exchange would require a loop and a strong one would not, the
+ strong one is preferable.
+
+ my_atomic_load#(&var)
+ my_atomic_load#_explicit(&var, memory_order)
+ return *var
+ Order must be one of MY_MEMORY_ORDER_RELAXED, MY_MEMORY_ORDER_CONSUME,
+ MY_MEMORY_ORDER_ACQUIRE, MY_MEMORY_ORDER_SEQ_CST.
+
+ my_atomic_store#(&var, what)
+ my_atomic_store#_explicit(&var, what, memory_order)
+ store 'what' in *var
+ Order must be one of MY_MEMORY_ORDER_RELAXED, MY_MEMORY_ORDER_RELEASE,
+ MY_MEMORY_ORDER_SEQ_CST.
+
+ '#' is substituted by a size suffix - 8, 16, 32, 64, or ptr
+ (e.g. my_atomic_add8, my_atomic_fas32, my_atomic_casptr).
+
+ The first version orders memory accesses according to MY_MEMORY_ORDER_SEQ_CST,
+ the second version (with _explicit suffix) orders memory accesses according to
+ given memory order.
+
+ memory_order specifies how non-atomic memory accesses are to be ordered around
+ an atomic operation:
+
+ MY_MEMORY_ORDER_RELAXED - there are no constraints on reordering of memory
+ accesses around the atomic variable.
+ MY_MEMORY_ORDER_CONSUME - no reads in the current thread dependent on the
+ value currently loaded can be reordered before this
+ load. This ensures that writes to dependent
+ variables in other threads that release the same
+ atomic variable are visible in the current thread.
+ On most platforms, this affects compiler
+ optimization only.
+ MY_MEMORY_ORDER_ACQUIRE - no reads in the current thread can be reordered
+ before this load. This ensures that all writes in
+ other threads that release the same atomic variable
+ are visible in the current thread.
+ MY_MEMORY_ORDER_RELEASE - no writes in the current thread can be reordered
+ after this store. This ensures that all writes in
+ the current thread are visible in other threads that
+ acquire the same atomic variable.
+ MY_MEMORY_ORDER_ACQ_REL - no reads in the current thread can be reordered
+ before this load as well as no writes in the current
+ thread can be reordered after this store. The
+ operation is read-modify-write operation. It is
+ ensured that all writes in another threads that
+ release the same atomic variable are visible before
+ the modification and the modification is visible in
+ other threads that acquire the same atomic variable.
+ MY_MEMORY_ORDER_SEQ_CST - The operation has the same semantics as
+ acquire-release operation, and additionally has
+ sequentially-consistent operation ordering.
+
+ We choose implementation as follows: on Windows using Visual C++ the native
+ implementation should be preferable. When using gcc we prefer the Solaris
+ implementation before the gcc because of stability preference, we choose gcc
+ builtins if available.
+*/
+
+#if defined(_MSC_VER)
+#include "atomic/generic-msvc.h"
+#elif defined(HAVE_SOLARIS_ATOMIC)
+#include "atomic/solaris.h"
+#elif defined(HAVE_GCC_C11_ATOMICS)
+#include "atomic/gcc_builtins.h"
+#endif
+
+#ifndef MY_MEMORY_ORDER_SEQ_CST
+#define MY_MEMORY_ORDER_RELAXED
+#define MY_MEMORY_ORDER_CONSUME
+#define MY_MEMORY_ORDER_ACQUIRE
+#define MY_MEMORY_ORDER_RELEASE
+#define MY_MEMORY_ORDER_ACQ_REL
+#define MY_MEMORY_ORDER_SEQ_CST
+
+#define my_atomic_store32_explicit(P, D, O) my_atomic_store32((P), (D))
+#define my_atomic_store64_explicit(P, D, O) my_atomic_store64((P), (D))
+#define my_atomic_storeptr_explicit(P, D, O) my_atomic_storeptr((P), (D))
+
+#define my_atomic_load32_explicit(P, O) my_atomic_load32((P))
+#define my_atomic_load64_explicit(P, O) my_atomic_load64((P))
+#define my_atomic_loadptr_explicit(P, O) my_atomic_loadptr((P))
+
+#define my_atomic_fas32_explicit(P, D, O) my_atomic_fas32((P), (D))
+#define my_atomic_fas64_explicit(P, D, O) my_atomic_fas64((P), (D))
+#define my_atomic_fasptr_explicit(P, D, O) my_atomic_fasptr((P), (D))
+
+#define my_atomic_add32_explicit(P, A, O) my_atomic_add32((P), (A))
+#define my_atomic_add64_explicit(P, A, O) my_atomic_add64((P), (A))
+#define my_atomic_addptr_explicit(P, A, O) my_atomic_addptr((P), (A))
+
+#define my_atomic_cas32_weak_explicit(P, E, D, S, F) \
+ my_atomic_cas32((P), (E), (D))
+#define my_atomic_cas64_weak_explicit(P, E, D, S, F) \
+ my_atomic_cas64((P), (E), (D))
+#define my_atomic_casptr_weak_explicit(P, E, D, S, F) \
+ my_atomic_casptr((P), (E), (D))
+
+#define my_atomic_cas32_strong_explicit(P, E, D, S, F) \
+ my_atomic_cas32((P), (E), (D))
+#define my_atomic_cas64_strong_explicit(P, E, D, S, F) \
+ my_atomic_cas64((P), (E), (D))
+#define my_atomic_casptr_strong_explicit(P, E, D, S, F) \
+ my_atomic_casptr((P), (E), (D))
+#endif
+#endif /* MY_ATOMIC_INCLUDED */