diff --git a/cmake/modules/SwiftSupport.cmake b/cmake/modules/SwiftSupport.cmake
index 4310b54c9..b67de9ced 100644
--- a/cmake/modules/SwiftSupport.cmake
+++ b/cmake/modules/SwiftSupport.cmake
@@ -23,6 +23,8 @@ function(get_swift_host_arch result_var_name)
     set("${result_var_name}" "armv7" PARENT_SCOPE)
   elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "armv7l")
     set("${result_var_name}" "armv7" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "amd64")
+    set("${result_var_name}" "x86_64" PARENT_SCOPE)
   elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "AMD64")
     set("${result_var_name}" "x86_64" PARENT_SCOPE)
   elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "IA64")
diff --git a/src/event/event_kevent.c b/src/event/event_kevent.c
index 16b69b37d..16cc6cbf4 100644
--- a/src/event/event_kevent.c
+++ b/src/event/event_kevent.c
@@ -389,8 +389,13 @@ _dispatch_kevent_print_error(dispatch_kevent_t ke)
 	case 0:
 		return;
 	case ERANGE: /* A broken QoS was passed to kevent_id() */
+#if defined(__APPLE__)
 		DISPATCH_INTERNAL_CRASH(ke->qos, "Invalid kevent priority");
+#else
+		DISPATCH_INTERNAL_CRASH(0, "Invalid kevent priority");
+#endif
 	default:
+#if HAVE_MACH
 		// log the unexpected error
 		_dispatch_bug_kevent_client("kevent", _evfiltstr(ke->filter),
 				!ke->udata ? NULL :
@@ -398,6 +403,9 @@ _dispatch_kevent_print_error(dispatch_kevent_t ke)
 				ke->flags & EV_ADD ? "add" :
 				ke->flags & EV_ENABLE ? "enable" : "monitor",
 				(int)ke->data, ke->ident, ke->udata, du);
+#else
+		break;
+#endif
 	}
 }
 
@@ -591,7 +599,6 @@ _dispatch_kq_create(intptr_t *fd_ptr)
 	guardid_t guard = (uintptr_t)fd_ptr;
 	kqfd = guarded_kqueue_np(&guard, GUARD_CLOSE | GUARD_DUP);
 #else
-	(void)guard_ptr;
 	kqfd = kqueue();
 #endif
 	if (kqfd == -1) {
@@ -743,7 +750,7 @@ _dispatch_kq_poll(dispatch_wlh_t wlh, dispatch_kevent_t ke, int n,
 		switch (err) {
 		case ENOMEM:
 			_dispatch_temporary_resource_shortage();
-			/* FALLTHROUGH */
+			DISPATCH_FALLTHROUGH;
 		case EINTR:
 			goto retry;
 		case EBADF:
@@ -754,7 +761,7 @@ _dispatch_kq_poll(dispatch_wlh_t wlh, dispatch_kevent_t ke, int n,
 					(flags & KEVENT_FLAG_DYNAMIC_KQ_MUST_EXIST)) {
 				return 0;
 			}
-			/* FALLTHROUGH */
+			DISPATCH_FALLTHROUGH;
 #endif // DISPATCH_USE_KEVENT_WORKLOOP
 		default:
 			DISPATCH_CLIENT_CRASH(err, "Unexpected error from kevent");
@@ -860,7 +867,6 @@ _dispatch_kq_unote_set_kevent(dispatch_unote_t _du, dispatch_kevent_t dk,
 				du->du_priority),
 #endif
 	};
-	(void)pp; // if DISPATCH_USE_KEVENT_QOS == 0
 }
 
 DISPATCH_ALWAYS_INLINE
@@ -985,6 +991,7 @@ _dispatch_sync_ipc_handoff_end(dispatch_wlh_t wlh, mach_port_t port)
 }
 #endif
 
+#if DISPATCH_HAVE_DIRECT_KNOTES
 DISPATCH_NOINLINE
 static bool
 _dispatch_kq_unote_update(dispatch_wlh_t wlh, dispatch_unote_t _du,
@@ -1055,6 +1062,7 @@ _dispatch_kq_unote_update(dispatch_wlh_t wlh, dispatch_unote_t _du,
 	dispatch_assume_zero(r);
 	return true;
 }
+#endif // DISPATCH_HAVE_DIRECT_KNOTES
 
 #pragma mark dispatch_muxnote_t
 
@@ -1300,6 +1308,7 @@ enum {
 	DISPATCH_WORKLOOP_SYNC_END,
 };
 
+#if DISPATCH_USE_KEVENT_WORKLOOP
 static char const * const _dispatch_workloop_actions[] = {
 	[DISPATCH_WORKLOOP_ASYNC]                       = "async",
 	[DISPATCH_WORKLOOP_ASYNC_FROM_SYNC]             = "async (from sync)",
@@ -1316,6 +1325,7 @@ static char const * const _dispatch_workloop_actions[] = {
 	[DISPATCH_WORKLOOP_SYNC_WAKE]                   = "sync-wake",
 	[DISPATCH_WORKLOOP_SYNC_END]                    = "sync-end",
 };
+#endif // DISPATCH_USE_KEVENT_WORKLOOP
 
 void
 _dispatch_event_loop_atfork_child(void)
diff --git a/src/init.c b/src/init.c
index f4c3bae4c..e14e6eb38 100644
--- a/src/init.c
+++ b/src/init.c
@@ -1048,7 +1048,7 @@ _dispatch_bug_kevent_vanished(dispatch_unote_t du)
 			"{ %p[%s], ident: %" PRIdPTR " / 0x%" PRIxPTR ", handler: %p }",
 			dux_type(du._du)->dst_kind, dou._dq,
 			dou._dq->dq_label ? dou._dq->dq_label : "<unknown>",
-			du._du->du_ident, du._du->du_ident, func);
+			(intptr_t)du._du->du_ident, (intptr_t)du._du->du_ident, func);
 }
 
 #endif // RDAR_49023449
diff --git a/src/internal.h b/src/internal.h
index cf4ccfe84..6f1ba1a96 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -36,7 +36,7 @@
 #define __DISPATCH_BUILDING_DISPATCH__
 #define __DISPATCH_INDIRECT__
 
-#ifdef __APPLE__
+#ifdef __APPLE__DISPATCH_USE_KEVENT_WORKLOOP
 #include <Availability.h>
 #include <os/availability.h>
 #include <TargetConditionals.h>
@@ -277,6 +277,9 @@ upcast(dispatch_object_t dou)
 #include <sys/sysctl.h>
 #include <sys/queue.h>
 #endif
+#if defined(__FreeBSD__)
+#include <sys/eventfd.h>
+#endif // __FreeBSD__
 #include <sys/socket.h>
 #include <sys/time.h>
 #include <sys/mman.h>
diff --git a/src/io.c b/src/io.c
index cbea654cb..ab247037c 100644
--- a/src/io.c
+++ b/src/io.c
@@ -22,7 +22,6 @@
 
 #if defined(__FreeBSD__)
 #include <fcntl.h>
-#define F_RDADVISE F_RDAHEAD
 #endif
 
 #ifndef DISPATCH_IO_DEBUG
diff --git a/src/queue.c b/src/queue.c
index 493de3f21..a5bdbb6ad 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -6467,7 +6467,7 @@ _dispatch_runloop_handle_is_valid(dispatch_runloop_handle_t handle)
 {
 #if TARGET_OS_MAC
 	return MACH_PORT_VALID(handle);
-#elif defined(__linux__)
+#elif defined(__linux__) || defined(__FreeBSD__)
 	return handle >= 0;
 #elif defined(_WIN32)
 	return handle != NULL;
@@ -6482,7 +6482,7 @@ _dispatch_runloop_queue_get_handle(dispatch_lane_t dq)
 {
 #if TARGET_OS_MAC
 	return ((dispatch_runloop_handle_t)(uintptr_t)dq->do_ctxt);
-#elif defined(__linux__)
+#elif defined(__linux__) || defined(__FreeBSD__)
 	// decode: 0 is a valid fd, so offset by 1 to distinguish from NULL
 	return ((dispatch_runloop_handle_t)(uintptr_t)dq->do_ctxt) - 1;
 #elif defined(_WIN32)
@@ -6499,7 +6499,7 @@ _dispatch_runloop_queue_set_handle(dispatch_lane_t dq,
 {
 #if TARGET_OS_MAC
 	dq->do_ctxt = (void *)(uintptr_t)handle;
-#elif defined(__linux__)
+#elif defined(__linux__) || defined(__FreeBSD__)
 	// encode: 0 is a valid fd, so offset by 1 to distinguish from NULL
 	dq->do_ctxt = (void *)(uintptr_t)(handle + 1);
 #elif defined(_WIN32)
@@ -6535,7 +6535,7 @@ _dispatch_runloop_queue_handle_init(void *ctxt)
 	(void)dispatch_assume_zero(kr);
 
 	handle = mp;
-#elif defined(__linux__)
+#elif defined(__linux__) || defined(__FreeBSD__)
 	int fd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
 	if (fd == -1) {
 		int err = errno;
@@ -6589,7 +6589,7 @@ _dispatch_runloop_queue_handle_dispose(dispatch_lane_t dq)
 	kr = mach_port_destruct(mach_task_self(), mp, -1, guard);
 	DISPATCH_VERIFY_MIG(kr);
 	(void)dispatch_assume_zero(kr);
-#elif defined(__linux__)
+#elif defined(__linux__) || defined(__FreeBSD__)
 	int rc = close(handle);
 	(void)dispatch_assume_zero(rc);
 #elif defined(_WIN32)
@@ -6622,7 +6622,7 @@ _dispatch_runloop_queue_class_poke(dispatch_lane_t dq)
 		(void)dispatch_assume_zero(kr);
 		break;
 	}
-#elif defined(__linux__)
+#elif defined(__linux__) || defined(__FreeBSD__)
 	int result;
 	do {
 		result = eventfd_write(handle, 1);
diff --git a/src/shims/lock.c b/src/shims/lock.c
index d4d63134a..07ea96cdd 100644
--- a/src/shims/lock.c
+++ b/src/shims/lock.c
@@ -56,6 +56,21 @@ _dispatch_thread_switch(dispatch_lock value, dispatch_lock_options_t flags,
 #endif
 #endif
 
+#if defined(__FreeBSD__)
+#if !HAVE_UL_UNFAIR_LOCK
+DISPATCH_ALWAYS_INLINE
+static inline void
+_dispatch_thread_switch(dispatch_lock value, dispatch_lock_options_t flags,
+		uint32_t timeout)
+{
+	(void)value;
+	(void)flags;
+	(void)timeout;
+	sched_yield();
+}
+#endif
+#endif
+
 #pragma mark - semaphores
 
 #if USE_MACH_SEM
@@ -509,6 +524,16 @@ _dispatch_wait_on_address(uint32_t volatile *_address, uint32_t value,
 	return _dispatch_futex_wait(address, value, NULL, FUTEX_PRIVATE_FLAG);
 #elif defined(_WIN32)
 	return WaitOnAddress(address, &value, sizeof(value), INFINITE) == TRUE;
+#elif defined(__FreeBSD__)
+  (void)flags;
+  if (nsecs != DISPATCH_TIME_FOREVER) {
+		struct timespec ts = {
+			.tv_sec = (__typeof__(ts.tv_sec))(nsecs / NSEC_PER_SEC),
+			.tv_nsec = (__typeof__(ts.tv_nsec))(nsecs % NSEC_PER_SEC),
+		};
+		return _umtx_op((void*)address, UMTX_OP_WAIT_UINT, value, (void*)(uintptr_t)sizeof(struct timespec), (void*)&ts);
+	}
+	return _umtx_op((void*)address, UMTX_OP_WAIT_UINT, value, 0, 0);
 #else
 #error _dispatch_wait_on_address unimplemented for this platform
 #endif
@@ -523,6 +548,8 @@ _dispatch_wake_by_address(uint32_t volatile *address)
 	_dispatch_futex_wake((uint32_t *)address, INT_MAX, FUTEX_PRIVATE_FLAG);
 #elif defined(_WIN32)
 	WakeByAddressAll((uint32_t *)address);
+#elif defined(__FreeBSD__)
+  _umtx_op((void*)address, UMTX_OP_WAKE, INT_MAX, 0, 0);
 #else
 	(void)address;
 #endif
@@ -682,7 +709,7 @@ _dispatch_once_wait(dispatch_once_gate_t dgo)
 		_dispatch_futex_wait(lock, (dispatch_lock)new_v, NULL,
 				FUTEX_PRIVATE_FLAG);
 #else
-		_dispatch_thread_switch(new_v, 0, timeout++);
+		_dispatch_thread_switch((dispatch_lock)new_v, 0, timeout++);
 #endif
 		(void)timeout;
 	}
diff --git a/src/shims/lock.h b/src/shims/lock.h
index 6bf825aa7..3ea77250e 100644
--- a/src/shims/lock.h
+++ b/src/shims/lock.h
@@ -67,7 +67,7 @@ typedef uint32_t dispatch_lock;
 
 #define DLOCK_OWNER_MASK			((dispatch_lock)FUTEX_TID_MASK)
 #define DLOCK_WAITERS_BIT			((dispatch_lock)FUTEX_WAITERS)
-#define DLOCK_FAILED_TRYLOCK_BIT	((dispatch_lock)FUTEX_OWNER_DIED)
+#define DLOCK_FAILED_TRYLOCK_BIT	((dispatch_lock)FUTEX_OWNER_DIED)HAVE_UL_COMPARE_AND_WAIT
 
 #define DLOCK_OWNER_NULL			((dispatch_tid)0)
 #define _dispatch_tid_self()        ((dispatch_tid)(_dispatch_get_tsd_base()->tid))
@@ -79,6 +79,29 @@ _dispatch_lock_owner(dispatch_lock lock_value)
 	return lock_value & DLOCK_OWNER_MASK;
 }
 
+#elif defined(__FreeBSD__)
+
+#include <sys/types.h>
+#include <sys/umtx.h>
+#include <sched.h>
+
+typedef uint32_t dispatch_tid;
+typedef uint32_t dispatch_lock;
+
+#define DLOCK_OWNER_MASK			((dispatch_lock)0x3fffffff)
+#define DLOCK_WAITERS_BIT			((dispatch_lock)UMUTEX_CONTESTED)
+#define DLOCK_FAILED_TRYLOCK_BIT	((dispatch_lock)UMUTEX_RB_OWNERDEAD)
+
+#define DLOCK_OWNER_NULL			((dispatch_tid)UMUTEX_UNOWNED)
+#define _dispatch_tid_self()        ((dispatch_tid)(_dispatch_get_tsd_base()->tid))
+
+DISPATCH_ALWAYS_INLINE
+static inline dispatch_tid
+_dispatch_lock_owner(dispatch_lock lock_value)
+{
+	return lock_value & DLOCK_OWNER_MASK;
+}
+
 #elif defined(_WIN32)
 
 #include <Windows.h>
diff --git a/src/swift/CMakeLists.txt b/src/swift/CMakeLists.txt
index 53924723e..57dd5e2cc 100644
--- a/src/swift/CMakeLists.txt
+++ b/src/swift/CMakeLists.txt
@@ -32,6 +32,7 @@ target_compile_options(swiftDispatch PRIVATE
   "SHELL:-Xcc -fblocks"
   "SHELL:-Xcc -fmodule-map-file=${PROJECT_SOURCE_DIR}/dispatch/module.modulemap"
   "SHELL:-Xcc -I${PROJECT_SOURCE_DIR}")
+
 set_target_properties(swiftDispatch PROPERTIES
   Swift_MODULE_NAME Dispatch
   Swift_MODULE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/swift
diff --git a/src/swift/Source.swift b/src/swift/Source.swift
index b4315c6cf..3a9fb779b 100644
--- a/src/swift/Source.swift
+++ b/src/swift/Source.swift
@@ -174,7 +174,7 @@ extension DispatchSource {
 	}
 #endif
 
-#if !os(Linux) && !os(Android) && !os(Windows)
+#if !os(Linux) && !os(Android) && !os(Windows) && !os(FreeBSD)
 	public class func makeProcessSource(identifier: pid_t, eventMask: ProcessEvent, queue: DispatchQueue? = nil) -> DispatchSourceProcess {
 		let source = dispatch_source_create(_swift_dispatch_source_type_PROC(), UInt(identifier), eventMask.rawValue, queue?.__wrapped)
 		return DispatchSource(source: source) as DispatchSourceProcess
@@ -224,7 +224,7 @@ extension DispatchSource {
 		return DispatchSource(source: source) as DispatchSourceUserDataReplace
 	}
 
-#if !os(Linux) && !os(Android) && !os(Windows)
+#if !os(Linux) && !os(Android) && !os(Windows) && !os(FreeBSD)
 	public class func makeFileSystemObjectSource(fileDescriptor: Int32, eventMask: FileSystemEvent, queue: DispatchQueue? = nil) -> DispatchSourceFileSystemObject {
 		let source = dispatch_source_create(_swift_dispatch_source_type_VNODE(), UInt(fileDescriptor), eventMask.rawValue, queue?.__wrapped)
 		return DispatchSource(source: source) as DispatchSourceFileSystemObject
@@ -290,7 +290,7 @@ extension DispatchSourceMemoryPressure {
 }
 #endif
 
-#if !os(Linux) && !os(Android) && !os(Windows)
+#if !os(Linux) && !os(Android) && !os(Windows) && !os(FreeBSD)
 extension DispatchSourceProcess {
 	public var handle: pid_t {
 		return pid_t(dispatch_source_get_handle(self as! DispatchSource))
diff --git a/src/swift/Wrapper.swift b/src/swift/Wrapper.swift
index 1bf26b184..d9af9d703 100644
--- a/src/swift/Wrapper.swift
+++ b/src/swift/Wrapper.swift
@@ -181,7 +181,7 @@ extension DispatchSource : DispatchSourceMachSend,
 }
 #endif
 
-#if !os(Linux) && !os(Android) && !os(Windows)
+#if !os(Linux) && !os(Android) && !os(Windows) && !os(FreeBSD)
 extension DispatchSource : DispatchSourceProcess,
 	DispatchSourceFileSystemObject {
 }
diff --git a/tests/bsdtestharness.c b/tests/bsdtestharness.c
index ca52d6e97..30a2cddc4 100644
--- a/tests/bsdtestharness.c
+++ b/tests/bsdtestharness.c
@@ -151,7 +151,7 @@ main(int argc, char *argv[])
 	//fprintf(stderr, "pid = %d\n", pid);
 	assert(pid > 0);
 
-#if defined(__linux__)
+#if defined(__linux__) || defined(__FreeBSD__)
 	int status;
 	struct rusage usage;
 	struct timeval tv_stop, tv_wall;
@@ -218,7 +218,7 @@ main(int argc, char *argv[])
 #else
 	dispatch_queue_t main_q = dispatch_get_main_queue();
 
-	dispatch_source_t tmp_ds = dispatch_source_create(DISPATCH_SOURCE_TYPE_PROC, pid, DISPATCH_PROC_EXIT, main_q);
+	dispatch_source_t tmp_ds = dispatch_source_create(DISPATCH_SOURCE_TYPE_PROC, (uintptr_t)pid, DISPATCH_PROC_EXIT, main_q);
 	assert(tmp_ds);
 	dispatch_source_set_event_handler(tmp_ds, ^{
 		int status;
diff --git a/tests/dispatch_apply.c b/tests/dispatch_apply.c
index fa7fab53f..2b0ad4d03 100644
--- a/tests/dispatch_apply.c
+++ b/tests/dispatch_apply.c
@@ -80,7 +80,7 @@ static void busythread(void *ignored)
 static void test_apply_contended(dispatch_queue_t dq)
 {
 	uint32_t activecpu;
-#if defined(__linux__) || defined(__OpenBSD__)
+#if defined(__linux__) || defined(__OpenBSD__) || defined(__FreeBSD__)
 	activecpu = (uint32_t)sysconf(_SC_NPROCESSORS_ONLN);
 #elif defined(_WIN32)
 	SYSTEM_INFO si;
diff --git a/tests/dispatch_io_pipe.c b/tests/dispatch_io_pipe.c
index f94438483..90c212236 100644
--- a/tests/dispatch_io_pipe.c
+++ b/tests/dispatch_io_pipe.c
@@ -90,6 +90,10 @@ test_get_pipe_buffer_size(int kind)
 		CloseHandle(write_handle);
 	});
 	return size;
+#elif defined(__FreeBSD__)
+	// buffer size of blocking and non-blocking pipes is different on FreeBSD
+	(void)kind;
+	return PIPE_BUF;
 #else
 	(void)kind;
 	static dispatch_once_t once;
diff --git a/tests/dispatch_select.c b/tests/dispatch_select.c
index 6202711cb..b0758707d 100644
--- a/tests/dispatch_select.c
+++ b/tests/dispatch_select.c
@@ -39,7 +39,7 @@ void finish(void* cxt);
 void
 stage1(int stage)
 {
-#if defined(_WIN32)
+#if defined(_WIN32) || defined(__FreeBSD__)
 	char *path = dispatch_test_get_large_file();
 	dispatch_fd_t fd = dispatch_test_fd_open(path, O_RDONLY);
 	if (fd == -1)