Provide atomic pointer support.

This is initially used for TLS to make loading the engine pointer
faster, eliminating a much more expensive lock operation.

4 files changed, 58 insertions, 4 deletions

diff --git a/src/platform/posix/posix_atomic.c b/src/platform/posix/posix_atomic.c
index 57ef709a..e4da9e77 100644
--- a/src/platform/posix/posix_atomic.c
+++ b/src/platform/posix/posix_atomic.c
@@ -1,5 +1,5 @@
 //
-// Copyright 2020 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2021 Staysail Systems, Inc. <info@staysail.tech>
 // Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
@@ -81,7 +81,19 @@ nni_atomic_get(nni_atomic_int *v)
 void
 nni_atomic_set(nni_atomic_int *v, int i)
 {
-	return (atomic_store(&v->v, i));
+	 atomic_store(&v->v, i);
+}
+
+void *
+nni_atomic_get_ptr(nni_atomic_ptr *v)
+{
+	return ((void *) atomic_load(&v->v));
+}
+
+void
+nni_atomic_set_ptr(nni_atomic_ptr *v, void *p)
+{
+	atomic_store(&v->v, (uintptr_t) p);
 }
 
 int
@@ -363,6 +375,24 @@ nni_atomic_set(nni_atomic_int *v, int i)
 	pthread_mutex_unlock(&plat_atomic_lock);
 }
 
+void *
+nni_atomic_get_ptr(nni_atomic_atomic *v)
+{
+	void *p;
+	pthread_mutex_lock(&plat_atomic_lock);
+	p = v->v;
+	pthread_mutex_unlock(&plat_atomic_lock);
+	return (p);
+}
+
+void
+nni_atomic_set_ptr(nni_atomic_atomic *v, void *p)
+{
+	pthread_mutex_lock(&plat_atomic_lock);
+	v->v = p;
+	pthread_mutex_unlock(&plat_atomic_lock);
+}
+
 int
 nni_atomic_swap(nni_atomic_int *v, int i)
 {
diff --git a/src/platform/posix/posix_impl.h b/src/platform/posix/posix_impl.h
index 851c80dc..234d1501 100644
--- a/src/platform/posix/posix_impl.h
+++ b/src/platform/posix/posix_impl.h
@@ -64,7 +64,7 @@ struct nni_rwlock {
 
 struct nni_plat_cv {
 	pthread_cond_t cv;
-	nni_plat_mtx * mtx;
+	nni_plat_mtx  *mtx;
 };
 
 struct nni_plat_thr {
@@ -99,6 +99,10 @@ struct nni_atomic_bool {
 	atomic_bool v;
 };
 
+struct nni_atomic_ptr {
+	atomic_uintptr_t v;
+};
+
 #else // NNG_HAVE_C11_ATOMIC
 struct nni_atomic_flag {
 	bool f;
@@ -116,6 +120,10 @@ struct nni_atomic_u64 {
 	uint64_t v;
 };
 
+struct nni_atomic_ptr {
+	void *v;
+};
+
 #endif
 
 #endif
diff --git a/src/platform/windows/win_impl.h b/src/platform/windows/win_impl.h
index de4f8e5b..608a065e 100644
--- a/src/platform/windows/win_impl.h
+++ b/src/platform/windows/win_impl.h
@@ -1,5 +1,5 @@
 //
-// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2021 Staysail Systems, Inc. <info@staysail.tech>
 // Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
@@ -67,6 +67,10 @@ struct nni_atomic_u64 {
 	LONGLONG v;
 };
 
+struct nni_atomic_ptr {
+	LONGLONG v;
+};
+
 // nni_win_io is used with io completion ports.  This allows us to get
 // to a specific completion callback without requiring the poller (in the
 // completion port) to know anything about the event itself.
diff --git a/src/platform/windows/win_thread.c b/src/platform/windows/win_thread.c
index 9c7c09d3..31e783a3 100644
--- a/src/platform/windows/win_thread.c
+++ b/src/platform/windows/win_thread.c
@@ -223,6 +223,18 @@ nni_atomic_set64(nni_atomic_u64 *v, uint64_t u)
 	(void) InterlockedExchange64(&v->v, (LONGLONG) u);
 }
 
+void *
+nni_atomic_get_ptr(nni_atomic_ptr *v)
+{
+	return ((void *) (InterlockedExchangeAdd64(&v->v, 0)));
+}
+
+void
+nni_atomic_set_ptr(nni_atomic_ptr *v)
+{
+	(void) InterlockedExchange64(&v->v, (LONGLONG) (uintptr_t) v);
+}
+
 uint64_t
 nni_atomic_swap64(nni_atomic_u64 *v, uint64_t u)
 {