Adding upstream version 5:7.2.4.upstream/5%7.2.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 158 insertions, 0 deletions

diff --git a/src/atomicvar.h b/src/atomicvar.h
new file mode 100644
index 0000000..2c2969c
--- /dev/null
+++ b/src/atomicvar.h
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+/* This file implements atomic counters using c11 _Atomic, __atomic or __sync
+ * macros if available, otherwise we will throw an error when compile.
+ *
+ * The exported interface is composed of three macros:
+ *
+ * atomicIncr(var,count) -- Increment the atomic counter
+ * atomicGetIncr(var,oldvalue_var,count) -- Get and increment the atomic counter
+ * atomicDecr(var,count) -- Decrement the atomic counter
+ * atomicGet(var,dstvar) -- Fetch the atomic counter value
+ * atomicSet(var,value)  -- Set the atomic counter value
+ * atomicGetWithSync(var,value)  -- 'atomicGet' with inter-thread synchronization
+ * atomicSetWithSync(var,value)  -- 'atomicSet' with inter-thread synchronization
+ *
+ * Never use return value from the macros, instead use the AtomicGetIncr()
+ * if you need to get the current value and increment it atomically, like
+ * in the following example:
+ *
+ *  long oldvalue;
+ *  atomicGetIncr(myvar,oldvalue,1);
+ *  doSomethingWith(oldvalue);
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * Copyright (c) 2015, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <pthread.h>
+#include "config.h"
+
+#ifndef __ATOMIC_VAR_H
+#define __ATOMIC_VAR_H
+
+/* Define redisAtomic for atomic variable. */
+#define redisAtomic
+
+/* To test Redis with Helgrind (a Valgrind tool) it is useful to define
+ * the following macro, so that __sync macros are used: those can be detected
+ * by Helgrind (even if they are less efficient) so that no false positive
+ * is reported. */
+// #define __ATOMIC_VAR_FORCE_SYNC_MACROS
+
+/* There will be many false positives if we test Redis with Helgrind, since
+ * Helgrind can't understand we have imposed ordering on the program, so
+ * we use macros in helgrind.h to tell Helgrind inter-thread happens-before
+ * relationship explicitly for avoiding false positives.
+ *
+ * For more details, please see: valgrind/helgrind.h and
+ * https://www.valgrind.org/docs/manual/hg-manual.html#hg-manual.effective-use
+ *
+ * These macros take effect only when 'make helgrind', and you must first
+ * install Valgrind in the default path configuration. */
+#ifdef __ATOMIC_VAR_FORCE_SYNC_MACROS
+#include <valgrind/helgrind.h>
+#else
+#define ANNOTATE_HAPPENS_BEFORE(v) ((void) v)
+#define ANNOTATE_HAPPENS_AFTER(v)  ((void) v)
+#endif
+
+#if !defined(__ATOMIC_VAR_FORCE_SYNC_MACROS) && defined(__STDC_VERSION__) && \
+    (__STDC_VERSION__ >= 201112L) && !defined(__STDC_NO_ATOMICS__)
+/* Use '_Atomic' keyword if the compiler supports. */
+#undef  redisAtomic
+#define redisAtomic _Atomic
+/* Implementation using _Atomic in C11. */
+
+#include <stdatomic.h>
+#define atomicIncr(var,count) atomic_fetch_add_explicit(&var,(count),memory_order_relaxed)
+#define atomicGetIncr(var,oldvalue_var,count) do { \
+    oldvalue_var = atomic_fetch_add_explicit(&var,(count),memory_order_relaxed); \
+} while(0)
+#define atomicDecr(var,count) atomic_fetch_sub_explicit(&var,(count),memory_order_relaxed)
+#define atomicGet(var,dstvar) do { \
+    dstvar = atomic_load_explicit(&var,memory_order_relaxed); \
+} while(0)
+#define atomicSet(var,value) atomic_store_explicit(&var,value,memory_order_relaxed)
+#define atomicGetWithSync(var,dstvar) do { \
+    dstvar = atomic_load_explicit(&var,memory_order_seq_cst); \
+} while(0)
+#define atomicSetWithSync(var,value) \
+    atomic_store_explicit(&var,value,memory_order_seq_cst)
+#define REDIS_ATOMIC_API "c11-builtin"
+
+#elif !defined(__ATOMIC_VAR_FORCE_SYNC_MACROS) && \
+    (!defined(__clang__) || !defined(__APPLE__) || __apple_build_version__ > 4210057) && \
+    defined(__ATOMIC_RELAXED) && defined(__ATOMIC_SEQ_CST)
+/* Implementation using __atomic macros. */
+
+#define atomicIncr(var,count) __atomic_add_fetch(&var,(count),__ATOMIC_RELAXED)
+#define atomicGetIncr(var,oldvalue_var,count) do { \
+    oldvalue_var = __atomic_fetch_add(&var,(count),__ATOMIC_RELAXED); \
+} while(0)
+#define atomicDecr(var,count) __atomic_sub_fetch(&var,(count),__ATOMIC_RELAXED)
+#define atomicGet(var,dstvar) do { \
+    dstvar = __atomic_load_n(&var,__ATOMIC_RELAXED); \
+} while(0)
+#define atomicSet(var,value) __atomic_store_n(&var,value,__ATOMIC_RELAXED)
+#define atomicGetWithSync(var,dstvar) do { \
+    dstvar = __atomic_load_n(&var,__ATOMIC_SEQ_CST); \
+} while(0)
+#define atomicSetWithSync(var,value) \
+    __atomic_store_n(&var,value,__ATOMIC_SEQ_CST)
+#define REDIS_ATOMIC_API "atomic-builtin"
+
+#elif defined(HAVE_ATOMIC)
+/* Implementation using __sync macros. */
+
+#define atomicIncr(var,count) __sync_add_and_fetch(&var,(count))
+#define atomicGetIncr(var,oldvalue_var,count) do { \
+    oldvalue_var = __sync_fetch_and_add(&var,(count)); \
+} while(0)
+#define atomicDecr(var,count) __sync_sub_and_fetch(&var,(count))
+#define atomicGet(var,dstvar) do { \
+    dstvar = __sync_sub_and_fetch(&var,0); \
+} while(0)
+#define atomicSet(var,value) do { \
+    while(!__sync_bool_compare_and_swap(&var,var,value)); \
+} while(0)
+/* Actually the builtin issues a full memory barrier by default. */
+#define atomicGetWithSync(var,dstvar) do { \
+    dstvar = __sync_sub_and_fetch(&var,0,__sync_synchronize); \
+    ANNOTATE_HAPPENS_AFTER(&var); \
+} while(0)
+#define atomicSetWithSync(var,value) do { \
+    ANNOTATE_HAPPENS_BEFORE(&var);  \
+    while(!__sync_bool_compare_and_swap(&var,var,value,__sync_synchronize)); \
+} while(0)
+#define REDIS_ATOMIC_API "sync-builtin"
+
+#else
+#error "Unable to determine atomic operations for your platform"
+
+#endif
+#endif /* __ATOMIC_VAR_H */