From 9ba00949dd0045451afa677bd3cc6540b2da53d8 Mon Sep 17 00:00:00 2001
From: Luke Howard <lukeh@padl.com>
Date: Mon, 13 Jul 2020 09:57:18 +1000
Subject: [PATCH] base: add atomic init, load and store macros

Add new macros for atomic initialization, load and store, with ordering
semantics equivalent to <stdatomic.h>
---
 lib/base/heimbase-atomics.h | 80 ++++++++++++++++++++++++++++++++-------------
 1 file changed, 58 insertions(+), 22 deletions(-)

diff --git a/lib/base/heimbase-atomics.h b/lib/base/heimbase-atomics.h
index 86e4ab91f..7d55202fd 100644
--- a/lib/base/heimbase-atomics.h
+++ b/lib/base/heimbase-atomics.h
@@ -43,12 +43,18 @@
  */
 
 #if defined(HAVE_STDATOMIC_H)
- 
+
 #include <stdatomic.h>
 
+#define heim_base_atomic_init(t, v)	atomic_init(t, v)
+#define heim_base_atomic_load(x)	atomic_load((x))
+#define heim_base_atomic_store(t, v)	atomic_store((t), (v))
+
+#define heim_base_atomic(T)		_Atomic(T)
+
 #define heim_base_atomic_inc(x)		(atomic_fetch_add((x), 1) + 1)
 #define heim_base_atomic_dec(x)		(atomic_fetch_sub((x), 1) - 1)
-#define heim_base_atomic_type		atomic_uint
+#define heim_base_atomic_type		heim_base_atomic(unsigned int)
 #define heim_base_atomic_max	 	UINT_MAX
 
 #define heim_base_exchange_pointer(t,v) atomic_exchange((t), (v))
@@ -57,10 +63,12 @@
 
 #elif defined(__GNUC__) && defined(HAVE___SYNC_ADD_AND_FETCH)
 
-#define heim_base_atomic_inc(x) __sync_add_and_fetch((x), 1)
-#define heim_base_atomic_dec(x) __sync_sub_and_fetch((x), 1)
-#define heim_base_atomic_type	unsigned int
-#define heim_base_atomic_max    UINT_MAX
+#define heim_base_atomic_barrier()	__sync_synchronize()
+
+#define heim_base_atomic_inc(x)		__sync_add_and_fetch((x), 1)
+#define heim_base_atomic_dec(x)		__sync_sub_and_fetch((x), 1)
+#define heim_base_atomic_type		unsigned int
+#define heim_base_atomic_max		UINT_MAX
 
 #ifndef __has_builtin
 #define __has_builtin(x) 0
@@ -80,10 +88,12 @@
 
 #include <sys/atomic.h>
 
-#define heim_base_atomic_inc(x) atomic_inc_uint_nv((volatile uint_t *)(x))
-#define heim_base_atomic_dec(x) atomic_dec_uint_nv((volatile uint_t *)(x))
-#define heim_base_atomic_type	uint_t
-#define heim_base_atomic_max    UINT_MAX
+#define heim_base_atomic_barrier()	__machine_rw_barrier()
+
+#define heim_base_atomic_inc(x)		atomic_inc_uint_nv((volatile uint_t *)(x))
+#define heim_base_atomic_dec(x)		atomic_dec_uint_nv((volatile uint_t *)(x))
+#define heim_base_atomic_type		uint_t
+#define heim_base_atomic_max		UINT_MAX
 
 #define heim_base_exchange_pointer(t,v) atomic_swap_ptr((volatile void *)(t), (void *)(v))
 #define heim_base_exchange_32(t,v)	atomic_swap_32((volatile uint32_t *)(t), (v))
@@ -93,10 +103,12 @@
 
 #include <sys/atomic_op.h>
 
-#define heim_base_atomic_inc(x) (fetch_and_add((atomic_p)(x)) + 1)
-#define heim_base_atomic_dec(x) (fetch_and_add((atomic_p)(x)) - 1)
-#define heim_base_atomic_type   unsigned int
-#define heim_base_atomic_max    UINT_MAX
+#define heim_base_atomic_barrier()	__isync()
+
+#define heim_base_atomic_inc(x)		(fetch_and_add((atomic_p)(x)) + 1)
+#define heim_base_atomic_dec(x)		(fetch_and_add((atomic_p)(x)) - 1)
+#define heim_base_atomic_type		unsigned int
+#define heim_base_atomic_max		UINT_MAX
 
 static inline void *
 heim_base_exchange_pointer(void *p, void *newval)
@@ -133,10 +145,12 @@ heim_base_exchange_64(uint64_t *p, uint64_t newval)
 
 #elif defined(_WIN32)
 
-#define heim_base_atomic_inc(x) InterlockedIncrement(x)
-#define heim_base_atomic_dec(x) InterlockedDecrement(x)
-#define heim_base_atomic_type	LONG
-#define heim_base_atomic_max    MAXLONG
+#define heim_base_atomic_barrier()	MemoryBarrier()
+
+#define heim_base_atomic_inc(x)		InterlockedIncrement(x)
+#define heim_base_atomic_dec(x)		InterlockedDecrement(x)
+#define heim_base_atomic_type		LONG
+#define heim_base_atomic_max		MAXLONG
 
 #define heim_base_exchange_pointer(t,v) InterlockedExchangePointer((PVOID volatile *)(t), (PVOID)(v))
 #define heim_base_exchange_32(t,v)	((ULONG)InterlockedExchange((LONG volatile *)(t), (LONG)(v)))
@@ -144,12 +158,13 @@ heim_base_exchange_64(uint64_t *p, uint64_t newval)
 
 #else
 
-#include "heim_threads.h"
+#include <heim_threads.h>
 
 #define HEIM_BASE_NEED_ATOMIC_MUTEX 1
 extern HEIMDAL_MUTEX _heim_base_mutex;
 
-#define heim_base_atomic_type	unsigned int
+#define heim_base_atomic_type		unsigned int
+#define heim_base_atomic_max		UINT_MAX
 
 static inline heim_base_atomic_type
 heim_base_atomic_inc(heim_base_atomic_type *x)
@@ -171,8 +186,6 @@ heim_base_atomic_dec(heim_base_atomic_type *x)
     return t;
 }
 
-#define heim_base_atomic_max    UINT_MAX
-
 static inline void *
 heim_base_exchange_pointer(void *target, void *value)
 {
@@ -208,6 +221,29 @@ heim_base_exchange_64(uint64_t *p, uint64_t newval)
 
 #endif /* defined(__GNUC__) && defined(HAVE___SYNC_ADD_AND_FETCH) */
 
+#ifndef heim_base_atomic
+#define heim_base_atomic(T)		T
+#endif
+
+#ifndef heim_base_atomic_barrier
+#define heim_base_atomic_barrier()
+#endif
+
+#ifndef heim_base_atomic_load
+#define heim_base_atomic_load(x)	(heim_base_atomic_barrier(), *(x))
+#endif
+
+#ifndef heim_base_atomic_init
+#define heim_base_atomic_init(t, v)	do { (*(t) = (v)); } while (0)
+#endif
+
+#ifndef heim_base_atomic_store
+#define heim_base_atomic_store(t, v)	do {					\
+					    (*(t) = (v));			\
+					    heim_base_atomic_barrier();		\
+					} while (0)
+#endif
+
 #if SIZEOF_TIME_T == 8
 #define heim_base_exchange_time_t(t,v)	heim_base_exchange_64((t), (v))
 #elif SIZEOF_TIME_T == 4
-- 
2.11.4.GIT