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d0017555c7
Replace C++ implementation of swift_beginAccess and swift_endAccess with (almost) pure Swift implementation. Helpers remain in C++ for TLS, getting return addresses, and raising a fatal error on violations. This change also moves the exclusivity access set head from the shared SwiftTLSContext structure to a dedicated TLS key. This improves performance, which is important for exclusivity checking. This is particularly the case where we can inline TLS access with a constant key, as on Darwin ARM64. The code that bridges exclusivity tracking into Concurrency remains in C++. The new Swift implementation exposes a few helpers for it to use as a replacement for directly manipulating the C++ implementation. rdar://161122309
69 lines
1.9 KiB
C++
69 lines
1.9 KiB
C++
//===--- SwiftTLSContext.cpp ----------------------------------------------===//
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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 - 2021 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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#include "SwiftTLSContext.h"
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#include "swift/Runtime/Heap.h"
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#include "swift/Threading/Once.h"
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#include "swift/Threading/ThreadLocalStorage.h"
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using namespace swift;
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using namespace swift::runtime;
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SwiftTLSContext &SwiftTLSContext::get() {
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#if SWIFT_THREADING_USE_RESERVED_TLS_KEYS
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// If we have reserved keys, use those
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SwiftTLSContext *ctx =
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static_cast<SwiftTLSContext *>(swift::tls_get(swift::tls_key::runtime));
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if (ctx)
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return *ctx;
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static swift::once_t token;
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swift::tls_init_once(token, swift::tls_key::runtime, [](void *pointer) {
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swift_cxx_deleteObject(static_cast<SwiftTLSContext *>(pointer));
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});
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ctx = swift_cxx_newObject<SwiftTLSContext>();
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swift::tls_set(swift::tls_key::runtime, ctx);
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return *ctx;
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#elif defined(SWIFT_THREAD_LOCAL)
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// If we have the thread local attribute, use that
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// (note that this happens for the no-threads case too)
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static SWIFT_THREAD_LOCAL SwiftTLSContext TLSContext;
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return TLSContext;
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#else
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// Otherwise, allocate ourselves a key and use that
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static swift::tls_key_t runtimeKey;
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static swift::once_t token;
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swift::tls_alloc_once(token, runtimeKey, [](void *pointer) {
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swift_cxx_deleteObject(static_cast<SwiftTLSContext *>(pointer));
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});
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SwiftTLSContext *ctx =
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static_cast<SwiftTLSContext *>(swift::tls_get(runtimeKey));
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if (ctx)
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return *ctx;
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ctx = swift_cxx_newObject<SwiftTLSContext>();
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swift::tls_set(runtimeKey, ctx);
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return *ctx;
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#endif
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}
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