Index: lib/libc/gen/Symbol.map
===================================================================
--- lib/libc/gen/Symbol.map
+++ lib/libc/gen/Symbol.map
@@ -485,7 +485,6 @@
 	_pthread_sigmask;
 	_pthread_testcancel;
 	_spinlock;
-	_spinlock_debug;
 	_spinunlock;
 	_rtld_addr_phdr;
 	_rtld_atfork_pre;
Index: lib/libc/gen/_spinlock_stub.c
===================================================================
--- lib/libc/gen/_spinlock_stub.c
+++ lib/libc/gen/_spinlock_stub.c
@@ -38,7 +38,6 @@
 long _atomic_lock_stub(volatile long *);
 void _spinlock_stub(spinlock_t *);
 void _spinunlock_stub(spinlock_t *);
-void _spinlock_debug_stub(spinlock_t *, char *, int);
 
 __weak_reference(_atomic_lock_stub, _atomic_lock);
 
@@ -48,7 +47,6 @@
 	return (0L);
 }
 
-__weak_reference(_spinlock, _spinlock_debug);
 #pragma weak _spinlock
 void
 _spinlock(spinlock_t *lck)
Index: lib/libc/include/spinlock.h
===================================================================
--- lib/libc/include/spinlock.h
+++ lib/libc/include/spinlock.h
@@ -41,21 +41,17 @@
  * Lock structure with room for debugging information.
  */
 struct _spinlock {
-	volatile long	access_lock;
-	volatile long	lock_owner;
-	volatile char	*fname;
-	volatile int	lineno;
+	long	spare1;
+	long	spare2;
+	void	*thr_extra;
+	int	spare3;
 };
 typedef struct _spinlock spinlock_t;
 
 #define	_SPINLOCK_INITIALIZER	{ 0, 0, 0, 0 }
 
 #define _SPINUNLOCK(_lck)	_spinunlock(_lck);
-#ifdef	_LOCK_DEBUG
-#define	_SPINLOCK(_lck)		_spinlock_debug(_lck, __FILE__, __LINE__)
-#else
 #define	_SPINLOCK(_lck)		_spinlock(_lck)
-#endif
 
 /*
  * Thread function prototype definitions:
@@ -64,7 +60,6 @@
 long	_atomic_lock(volatile long *);
 void	_spinlock(spinlock_t *);
 void	_spinunlock(spinlock_t *);
-void	_spinlock_debug(spinlock_t *, char *, int);
 __END_DECLS
 
 #endif /* _SPINLOCK_H_ */
Index: lib/libthr/Makefile
===================================================================
--- lib/libthr/Makefile
+++ lib/libthr/Makefile
@@ -16,7 +16,7 @@
 
 LIB=thr
 SHLIB_MAJOR= 3
-WARNS?=	3
+NO_WTHREAD_SAFETY=1
 CFLAGS+=-DPTHREAD_KERNEL
 CFLAGS+=-I${SRCTOP}/lib/libc/include -I${.CURDIR}/thread \
 	-I${SRCTOP}/include
@@ -27,6 +27,12 @@
 CFLAGS+=-I${SRCTOP}/lib/libthread_db
 CFLAGS+=-Winline
 
+CFLAGS.thr_stack.c+=	-Wno-cast-align
+.include <bsd.compiler.mk>
+.if !(${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} < 40300)
+CFLAGS.thr_symbols.c+=	-Wno-missing-variable-declarations
+.endif
+
 .ifndef NO_THREAD_UNWIND_STACK
 CFLAGS+=-fexceptions
 CFLAGS+=-D_PTHREAD_FORCED_UNWIND
Index: lib/libthr/thread/thr_init.c
===================================================================
--- lib/libthr/thread/thr_init.c
+++ lib/libthr/thread/thr_init.c
@@ -173,7 +173,6 @@
 STATIC_LIB_REQUIRE(_sigwait);
 STATIC_LIB_REQUIRE(_sigwaitinfo);
 STATIC_LIB_REQUIRE(_spinlock);
-STATIC_LIB_REQUIRE(_spinlock_debug);
 STATIC_LIB_REQUIRE(_spinunlock);
 STATIC_LIB_REQUIRE(_thread_init_hack);
 
Index: lib/libthr/thread/thr_rwlock.c
===================================================================
--- lib/libthr/thread/thr_rwlock.c
+++ lib/libthr/thread/thr_rwlock.c
@@ -49,27 +49,42 @@
 __weak_reference(_pthread_rwlock_wrlock, pthread_rwlock_wrlock);
 __weak_reference(_pthread_rwlock_timedwrlock, pthread_rwlock_timedwrlock);
 
-#define CHECK_AND_INIT_RWLOCK							\
-	if (*rwlock == THR_PSHARED_PTR) {					\
-		prwlock = __thr_pshared_offpage(rwlock, 0);			\
-		if (prwlock == NULL)						\
-			return (EINVAL);					\
-	} else if (__predict_false((prwlock = (*rwlock)) <=			\
-	    THR_RWLOCK_DESTROYED)) {						\
-		if (prwlock == THR_RWLOCK_INITIALIZER) {			\
-			int ret;						\
-			ret = init_static(_get_curthread(), rwlock);		\
-			if (ret)						\
-				return (ret);					\
-		} else if (prwlock == THR_RWLOCK_DESTROYED) {			\
-			return (EINVAL);					\
-		}								\
-		prwlock = *rwlock;						\
-	}
+static int init_static(struct pthread *thread, pthread_rwlock_t *rwlock);
+static int init_rwlock(pthread_rwlock_t *rwlock, pthread_rwlock_t *rwlock_out);
 
-/*
- * Prototypes
- */
+static int __always_inline
+check_and_init_rwlock(pthread_rwlock_t *rwlock, pthread_rwlock_t *rwlock_out)
+{
+	if (__predict_false(*rwlock == THR_PSHARED_PTR ||
+	    *rwlock <= THR_RWLOCK_DESTROYED))
+		return (init_rwlock(rwlock, rwlock_out));
+	*rwlock_out = *rwlock;
+	return (0);
+}
+
+static int __noinline
+init_rwlock(pthread_rwlock_t *rwlock, pthread_rwlock_t *rwlock_out)
+{
+	pthread_rwlock_t prwlock;
+	int ret;
+
+	if (*rwlock == THR_PSHARED_PTR) {
+		prwlock = __thr_pshared_offpage(rwlock, 0);
+		if (prwlock == NULL)
+			return (EINVAL);
+	} else if ((prwlock = *rwlock) <= THR_RWLOCK_DESTROYED) {
+		if (prwlock == THR_RWLOCK_INITIALIZER) {
+			ret = init_static(_get_curthread(), rwlock);
+			if (ret != 0)
+				return (ret);
+		} else if (prwlock == THR_RWLOCK_DESTROYED) {
+			return (EINVAL);
+		}
+		prwlock = *rwlock;
+	}
+	*rwlock_out = prwlock;
+	return (0);
+}
 
 static int
 rwlock_init(pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr)
@@ -148,7 +163,9 @@
 	int flags;
 	int ret;
 
-	CHECK_AND_INIT_RWLOCK
+	ret = check_and_init_rwlock(rwlock, &prwlock);
+	if (ret != 0)
+		return (ret);
 
 	if (curthread->rdlock_count) {
 		/*
@@ -220,7 +237,9 @@
 	int flags;
 	int ret;
 
-	CHECK_AND_INIT_RWLOCK
+	ret = check_and_init_rwlock(rwlock, &prwlock);
+	if (ret != 0)
+		return (ret);
 
 	if (curthread->rdlock_count) {
 		/*
@@ -253,7 +272,9 @@
 	pthread_rwlock_t prwlock;
 	int ret;
 
-	CHECK_AND_INIT_RWLOCK
+	ret = check_and_init_rwlock(rwlock, &prwlock);
+	if (ret != 0)
+		return (ret);
 
 	ret = _thr_rwlock_trywrlock(&prwlock->lock);
 	if (ret == 0)
@@ -268,7 +289,9 @@
 	pthread_rwlock_t prwlock;
 	int ret;
 
-	CHECK_AND_INIT_RWLOCK
+	ret = check_and_init_rwlock(rwlock, &prwlock);
+	if (ret != 0)
+		return (ret);
 
 	/*
 	 * POSIX said the validity of the abstimeout parameter need
Index: lib/libthr/thread/thr_spinlock.c
===================================================================
--- lib/libthr/thread/thr_spinlock.c
+++ lib/libthr/thread/thr_spinlock.c
@@ -65,7 +65,7 @@
 {
 	struct spinlock_extra	*_extra;
 
-	_extra = (struct spinlock_extra *)lck->fname;
+	_extra = lck->thr_extra;
 	THR_UMUTEX_UNLOCK(_get_curthread(), &_extra->lock);
 }
 
@@ -78,9 +78,9 @@
 		PANIC("Spinlock called when not threaded.");
 	if (!initialized)
 		PANIC("Spinlocks not initialized.");
-	if (lck->fname == NULL)
+	if (lck->thr_extra == NULL)
 		init_spinlock(lck);
-	_extra = (struct spinlock_extra *)lck->fname;
+	_extra = lck->thr_extra;
 	THR_UMUTEX_LOCK(_get_curthread(), &_extra->lock);
 }
 
@@ -90,14 +90,14 @@
 	struct pthread *curthread = _get_curthread();
 
 	THR_UMUTEX_LOCK(curthread, &spinlock_static_lock);
-	if ((lck->fname == NULL) && (spinlock_count < MAX_SPINLOCKS)) {
-		lck->fname = (char *)&extra[spinlock_count];
+	if ((lck->thr_extra == NULL) && (spinlock_count < MAX_SPINLOCKS)) {
+		lck->thr_extra = &extra[spinlock_count];
 		_thr_umutex_init(&extra[spinlock_count].lock);
 		extra[spinlock_count].owner = lck;
 		spinlock_count++;
 	}
 	THR_UMUTEX_UNLOCK(curthread, &spinlock_static_lock);
-	if (lck->fname == NULL)
+	if (lck->thr_extra == NULL)
 		PANIC("Warning: exceeded max spinlocks");
 }
 
Index: lib/libthr/thread/thr_stack.c
===================================================================
--- lib/libthr/thread/thr_stack.c
+++ lib/libthr/thread/thr_stack.c
@@ -290,19 +290,6 @@
 		return (-1);
 }
 
-/*
- * Disable this warning from clang:
- *
- * cast from 'char *' to
- *    'struct stack *' increases required alignment from 1 to 8
- *    [-Werror,-Wcast-align]
- *                 spare_stack = (struct stack *)
- */
-#ifdef __clang__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wcast-align"
-#endif
-
 /* This function must be called with _thread_list_lock held. */
 void
 _thr_stack_free(struct pthread_attr *attr)
@@ -329,7 +316,3 @@
 		attr->stackaddr_attr = NULL;
 	}
 }
-
-#ifdef __clang__
-#pragma GCC diagnostic pop
-#endif
Index: lib/libthr/thread/thr_symbols.c
===================================================================
--- lib/libthr/thread/thr_symbols.c
+++ lib/libthr/thread/thr_symbols.c
@@ -37,10 +37,6 @@
 
 #include "thr_private.h"
 
-#ifdef __clang__
-#pragma GCC diagnostic ignored "-Wmissing-variable-declarations"
-#endif
-
 /* A collection of symbols needed by debugger */
 
 /* int _libthr_debug */