Add Redis source code for testing

1 files changed, 186 insertions, 0 deletions

diff --git a/examples/redis-unstable/src/atomicvar.h b/examples/redis-unstable/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 the following macros:
+ *
+ * atomicIncr(var,count) -- Increment the atomic counter
+ * atomicGetIncr(var,oldvalue_var,count) -- Get and increment the atomic counter
+ * atomicIncrGet(var,newvalue_var,count) -- Increment and get the atomic counter new value
+ * 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
+ * atomicCompareExchange(type,var,expected_var,desired)  --  Compare and exchange (CAS) operation
+ * 
+ * Atomic operations on flags. 
+ * Flag type can be int, long, long long or their unsigned counterparts.
+ * The value of the flag can be 1 or 0.
+ * 
+ * atomicFlagGetSet(var,oldvalue_var) -- Get and set the atomic counter value
+ * 
+ * NOTE1: __atomic* and _Atomic implementations can be actually elaborated to support any value by changing the 
+ * hardcoded new value passed to __atomic_exchange* from 1 to @param count
+ * i.e oldvalue_var = atomic_exchange_explicit(&var, count).
+ * However, in order to be compatible with the __sync functions family, we can use only 0 and 1.
+ * The only exchange alternative suggested by __sync is __sync_lock_test_and_set, 
+ * But as described by the gnu manual for __sync_lock_test_and_set():
+ * https://gcc.gnu.org/onlinedocs/gcc/_005f_005fsync-Builtins.html
+ * "A target may support reduced functionality here by which the only valid value to store is the immediate constant 1. The exact value
+ * actually stored in *ptr is implementation defined."
+ * Hence, we can't rely on it for a any value other than 1.
+ * We eventually chose to implement this method with __sync_val_compare_and_swap since it satisfies functionality needed for atomicFlagGetSet
+ * (if the flag was 0 -> set to 1, if it's already 1 -> do nothing, but the final result is that the flag is set), 
+ * and also it has a full barrier (__sync_lock_test_and_set has acquire barrier).
+ * 
+ * NOTE2: Unlike other atomic type, which aren't guaranteed to be lock free, c11 atomic_flag does.
+ * To check whether a type is lock free, atomic_is_lock_free() can be used. 
+ * It can be considered to limit the flag type to atomic_flag to improve performance.
+ * 
+ * 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-Present, Redis Ltd.
+ * All rights reserved.
+ *
+ * Licensed under your choice of (a) the Redis Source Available License 2.0
+ * (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the
+ * GNU Affero General Public License v3 (AGPLv3).
+ */
+
+#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 atomicIncrGet(var, newvalue_var, count) \
+    newvalue_var = atomicIncr(var,count) + count
+#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 atomicCompareExchange(type,var,expected_var,desired) \
+    atomic_compare_exchange_weak_explicit(&var,&expected_var,desired,memory_order_relaxed,memory_order_relaxed)
+#define atomicFlagGetSet(var,oldvalue_var) \
+    oldvalue_var = atomic_exchange_explicit(&var,1,memory_order_relaxed)
+#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 atomicIncrGet(var, newvalue_var, count) \
+    newvalue_var = __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 atomicCompareExchange(type,var,expected_var,desired) \
+    __atomic_compare_exchange_n(&var,&expected_var,desired,1,__ATOMIC_RELAXED,__ATOMIC_RELAXED)
+#define atomicFlagGetSet(var,oldvalue_var) \
+    oldvalue_var = __atomic_exchange_n(&var,1,__ATOMIC_RELAXED)
+#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 atomicIncrGet(var, newvalue_var, count) \
+    newvalue_var = __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 atomicCompareExchange(type,var,expected_var,desired) ({ \
+    type _old = __sync_val_compare_and_swap(&var,expected_var,desired); \
+    int _success = (_old == expected_var); \
+    if (!_success) expected_var = _old; \
+    _success; \
+})
+#define atomicFlagGetSet(var,oldvalue_var) \
+    oldvalue_var = __sync_val_compare_and_swap(&var,0,1)
+#define REDIS_ATOMIC_API "sync-builtin"
+
+#else
+#error "Unable to determine atomic operations for your platform"
+
+#endif
+#endif /* __ATOMIC_VAR_H */