1 files changed, 140 insertions, 0 deletions
diff --git a/src/corelib/thread/qfutex_mac_p.h b/src/corelib/thread/qfutex_mac_p.h
new file mode 100644
index 0000000000..0de08954ab
--- /dev/null
+++ b/src/corelib/thread/qfutex_mac_p.h
@@ -0,0 +1,140 @@
+// Copyright (C) 2023 Intel Corporation.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QFUTEX_MAC_P_H
+#define QFUTEX_MAC_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <qdeadlinetimer.h>
+#include <qtsan_impl.h>
+#include <private/qglobal_p.h>
+
+// The Darwin kernel exposes a set of __ulock_{wait,wait2,wake} APIs in
+// https://github.com/apple-oss-distributions/xnu/blob/xnu-8792.81.2/bsd/sys/ulock.h,
+// but these APIs are marked as private, so we cannot rely on them being
+// stable, nor we can use these APIs in builds of Qt intended for
+// the Apple App Store. By wholesale disabling the use of the APIs
+// in App Store compliant builds, and runtime checking availability
+// of the APIs when we do build them in, we should be safe, unless
+// the semantics of the APIs change in ways we haven't accounted for,
+// but that's a risk we're willing to take.
+
+#if QT_CONFIG(appstore_compliant)
+QT_BEGIN_NAMESPACE
+namespace QtFutex = QtDummyFutex;
+QT_END_NAMESPACE
+#else
+
+extern "C" {
+// -------- BEGIN OS Declarations --------
+// Source: https://github.com/apple-oss-distributions/xnu/blob/xnu-8792.81.2/bsd/sys/ulock.h
+// Modification: added __attribute((__weak__))
+// Copyright (c) 2015 Apple Inc. All rights reserved.
+
+__attribute((__weak__))
+extern int __ulock_wait2(uint32_t operation, void *addr, uint64_t value,
+    uint64_t timeout, uint64_t value2);
+__attribute((__weak__))
+extern int __ulock_wake(uint32_t operation, void *addr, uint64_t wake_value);
+
+/*
+ * operation bits [7, 0] contain the operation code.
+ */
+#define UL_COMPARE_AND_WAIT             1
+#define UL_COMPARE_AND_WAIT_SHARED      3
+#define UL_COMPARE_AND_WAIT64           5
+#define UL_COMPARE_AND_WAIT64_SHARED    6
+
+/*
+ * operation bits [15, 8] contain the flags for __ulock_wake
+ */
+#define ULF_WAKE_ALL                    0x00000100
+#define ULF_WAKE_THREAD                 0x00000200
+#define ULF_WAKE_ALLOW_NON_OWNER        0x00000400
+
+/*
+ * operation bits [15, 8] contain the flags for __ulock_wake
+ */
+#define ULF_WAKE_ALL                    0x00000100
+#define ULF_WAKE_THREAD                 0x00000200
+#define ULF_WAKE_ALLOW_NON_OWNER        0x00000400
+
+/*
+ * operation bits [31, 24] contain the generic flags
+ */
+#define ULF_NO_ERRNO                    0x01000000
+
+// -------- END OS Declarations --------
+} // extern "C"
+
+QT_BEGIN_NAMESPACE
+
+namespace QtDarwinFutex {
+
+/*not constexpr*/ inline bool futexAvailable() { return __ulock_wake && __ulock_wait2; }
+
+template <typename Atomic>
+inline uint32_t baseOperation(Atomic &)
+{
+    static_assert(sizeof(Atomic) >= sizeof(quint32), "Can only operate on 32- or 64-bit atomics");
+
+    uint32_t operation = ULF_NO_ERRNO;
+    if (sizeof(Atomic) == sizeof(quint32))
+        operation |= UL_COMPARE_AND_WAIT;
+    else
+        operation |= UL_COMPARE_AND_WAIT64;
+    return operation;
+}
+
+template <typename Atomic> inline int
+do_wait(Atomic &futex, typename Atomic::Type expectedValue, QDeadlineTimer timer)
+{
+    // source code inspection shows __ulock_wait2 uses nanoseconds for timeout
+    QtTsan::futexRelease(&futex);
+    int ret = __ulock_wait2(baseOperation(futex), &futex, uint64_t(expectedValue),
+                            timer.remainingTimeNSecs(), 0);
+    QtTsan::futexAcquire(&futex);
+    return ret;
+}
+
+template <typename Atomic>
+inline void futexWait(Atomic &futex, typename Atomic::Type expectedValue)
+{
+    do_wait(futex, expectedValue, {});
+}
+
+template <typename Atomic>
+inline bool futexWait(Atomic &futex, typename Atomic::Type expectedValue, QDeadlineTimer timer)
+{
+    int r = do_wait(futex, expectedValue, timer);
+    return r == 0 || r != -ETIMEDOUT;
+}
+
+template <typename Atomic> inline void futexWakeAll(Atomic &futex)
+{
+    __ulock_wake(baseOperation(futex) | ULF_WAKE_ALL, &futex, 0);
+}
+
+template <typename Atomic> inline void futexWakeOne(Atomic &futex)
+{
+    __ulock_wake(baseOperation(futex), &futex, 0);
+}
+} //namespace QtDarwinMutex
+
+namespace QtFutex = QtDarwinFutex;
+
+QT_END_NAMESPACE
+
+#endif // QT_CONFIG(appstore_compliant)
+
+#endif // QFUTEX_MAC_P_H