From a85a65f96eba4ed12e69ca0f539b29713549feab Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Witold=20Kr=C4=99cicki?= <wpk@isc.org>
Date: Thu, 24 Oct 2019 10:55:54 +0200
Subject: [PATCH] add atomic_exchange operations to mutexatomic.h and win32
 stdatomic.h

---
 lib/isc/include/isc/mutexatomic.h     | 16 ++++++++++++++++
 lib/isc/unix/include/isc/stdatomic.h  | 11 +++++++++++
 lib/isc/win32/include/isc/stdatomic.h | 23 +++++++++++++++++++++--
 3 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/lib/isc/include/isc/mutexatomic.h b/lib/isc/include/isc/mutexatomic.h
index c111081ee9..94d8998822 100644
--- a/lib/isc/include/isc/mutexatomic.h
+++ b/lib/isc/include/isc/mutexatomic.h
@@ -93,6 +93,11 @@ typedef struct atomic_uint_fast64 {
 	uint64_t v;
 } atomic_uint_fast64_t;
 
+typedef struct atomic_uintptr {
+	isc_mutex_t m;
+	uintptr_t v;
+} atomic_uintptr_t;
+
 typedef struct atomic_bool_s {
 	isc_mutex_t m;
 	bool v;
@@ -198,3 +203,14 @@ typedef struct atomic_bool_s {
 	atomic_compare_exchange_weak_explicit(obj, expected, desired, \
 					      memory_order_seq_cst,   \
 					      memory_order_seq_cst)
+#define atomic_exchange_explicit(obj, desired, order)			\
+	({								\
+		typeof((obj)->v) ___v;					\
+		REQUIRE(isc_mutex_lock(&(obj)->m) == ISC_R_SUCCESS);	\
+		___v = (obj)->v;					\
+		(obj)->v = desired;					\
+		REQUIRE(isc_mutex_unlock(&(obj)->m) == ISC_R_SUCCESS);	\
+		___v;							\
+	})
+#define atomic_exchange(obj, desired) \
+	atomic_exchange_explicit(obj, desired, memory_order_seq_cst)
diff --git a/lib/isc/unix/include/isc/stdatomic.h b/lib/isc/unix/include/isc/stdatomic.h
index f0909d232b..8e423a961b 100644
--- a/lib/isc/unix/include/isc/stdatomic.h
+++ b/lib/isc/unix/include/isc/stdatomic.h
@@ -80,6 +80,8 @@ typedef int_fast64_t	atomic_int_fast64_t;
 typedef uint_fast64_t	atomic_uint_fast64_t;
 typedef bool		atomic_bool;
 
+typedef uint_fast64_t	atomic_uintptr_t;
+
 #if defined(__CLANG_ATOMICS) /* __c11_atomic builtins */
 #define atomic_init(obj, desired)		\
 	__c11_atomic_init(obj, desired)
@@ -99,6 +101,8 @@ typedef bool		atomic_bool;
 	__c11_atomic_compare_exchange_strong_explicit(obj, expected, desired, succ, fail)
 #define atomic_compare_exchange_weak_explicit(obj, expected, desired, succ, fail)	\
 	__c11_atomic_compare_exchange_weak_explicit(obj, expected, desired, succ, fail)
+#define atomic_exchange_explicit(obj, desired, order)	\
+	__c11_atomic_exchange_explicit(obj, expected, order)
 #elif defined(__GNUC_ATOMICS) /* __atomic builtins */
 #define atomic_init(obj, desired)			\
 	(*obj = desired)
@@ -118,6 +122,8 @@ typedef bool		atomic_bool;
 	__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)
 #else /* __sync builtins */
 #define atomic_init(obj, desired)			\
 	(*obj = desired)
@@ -150,6 +156,9 @@ typedef bool		atomic_bool;
 	})
 #define atomic_compare_exchange_weak_explicit(obj, expected, desired, succ, fail)	\
 	atomic_compare_exchange_strong_explicit(obj, expected, desired, succ, fail)
+#define atomic_exchange_explicit(obj, desired, order) \
+	__sync_lock_test_and_set(obj, desired)
+
 #endif
 
 #define atomic_load(obj) \
@@ -168,3 +177,5 @@ typedef bool		atomic_bool;
 	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)
diff --git a/lib/isc/win32/include/isc/stdatomic.h b/lib/isc/win32/include/isc/stdatomic.h
index 62c2de14be..60ac199af2 100644
--- a/lib/isc/win32/include/isc/stdatomic.h
+++ b/lib/isc/win32/include/isc/stdatomic.h
@@ -397,8 +397,7 @@ atomic_compare_exchange_strong_explicit64(atomic_int_fast64_t *obj,
 	return (__r);
 }
 
-static inline
-bool
+static inline bool
 atomic_compare_exchange_abort() {
 	INSIST(0);
 	ISC_UNREACHABLE();
@@ -434,3 +433,23 @@ atomic_compare_exchange_abort() {
 	atomic_compare_exchange_weak_explicit(obj, expected, desired,	\
 					      memory_order_seq_cst,	\
 					      memory_order_seq_cst)
+
+static inline
+bool
+atomic_exchange_abort() {
+	INSIST(0);
+	ISC_UNREACHABLE();
+}
+
+
+#define atomic_exchange_explicit(obj, desired, order)	\
+	(sizeof(*(obj)) == 8				\
+	 ? InterlockedExchange64(obj, desired) 		\
+	 : (sizeof(*(obj)) == 4				\
+	    ? InterlockedExchange(obj, desired)		\
+		: (sizeof(*(obj)) == 1			\
+		? InterlockedExchange8(obj, desired)	\
+		    : atomic_exchange_abort())))
+
+#define atomic_exchange(obj, desired)					\
+	atomic_exchange_explicit(obj, desired, memory_order_seq_cst)	\