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dadcb04ae2
SWIFT_STDLIB_SINGLE_THREADED_RUNTIME is too much of a blunt instrument here. It covers both the Concurrency runtime and the rest of the runtime, but we'd like to be able to have e.g. a single-threaded Concurrency runtime while the rest of the runtime is still thread safe (for instance). So: rename it to SWIFT_STDLIB_SINGLE_THREADED_CONCURRENCY and make it just control the Concurrency runtime, then add a SWIFT_STDLIB_THREADING_PACKAGE setting at the CMake/build-script level, which defines SWIFT_STDLIB_THREADING_xxx where xxx depends on the chosen threading package. This is especially useful on systems where there may be a choice of threading package that you could use. rdar://90776105
60 lines
1.6 KiB
C++
60 lines
1.6 KiB
C++
//===--- Once.h - Runtime support for lazy initialization -------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// Swift runtime functions in support of lazy initialization.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_RUNTIME_ONCE_H
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#define SWIFT_RUNTIME_ONCE_H
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#include "swift/Runtime/HeapObject.h"
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#if SWIFT_STDLIB_THREADING_DARWIN
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#include <dispatch/dispatch.h>
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#else
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#include <mutex>
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#endif
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namespace swift {
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#ifdef SWIFT_STDLIB_THREADING_NONE
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typedef bool swift_once_t;
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#elif SWIFT_STDLIB_THREADING_DARWIN
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// On OS X and iOS, swift_once_t is really a dispatch_once_t.
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typedef dispatch_once_t swift_once_t;
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#elif defined(__CYGWIN__)
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// On Cygwin, std::once_flag can not be used because it is larger than the
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// platform word.
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typedef uintptr_t swift_once_t;
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#else
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// On other platforms swift_once_t is std::once_flag
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typedef std::once_flag swift_once_t;
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#endif
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/// Runs the given function with the given context argument exactly once.
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/// The predicate argument must point to a global or static variable of static
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/// extent of type swift_once_t.
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SWIFT_RUNTIME_EXPORT
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void swift_once(swift_once_t *predicate, void (*fn)(void *), void *context);
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}
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#endif
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