Files
swift-mirror/stdlib/public/runtime/SwiftTLSContext.cpp
Michael Gottesman 3e64d03a52 [exclusivity] Split out of Exclusivity.cpp FunctionReplacement and the Global TLSContext.
Some notes:

1. Even though I refactored out AccessSet/Access from Exclusivity.cpp ->
ExclusivityPrivate.h, I left the actual implementations of insert/remove in
Exclusivity.cpp to allow for the most aggressive optimization for use in
Exclusivity.cpp without exposing a bunch of internal details to other parts of
the runtime. Smaller routines like getHead() and manipulating the linked list
directly I left as methods that can be used by other parts of the runtime. I am
going to use these methods to enable backwards deployment of exclusivity support
for concurrency.

2. I moved function replacements out of the Exclusivity header/cpp files since
it has nothing to do with Exclusivity beyond taking advantage of the TLS context
that we are already using.
2021-07-26 12:26:08 -07:00

92 lines
2.4 KiB
C++

//===--- SwiftTLSContext.cpp ----------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#include "SwiftTLSContext.h"
#include "swift/Basic/Lazy.h"
#include "swift/Runtime/Once.h"
#include "swift/Runtime/ThreadLocalStorage.h"
using namespace swift;
using namespace swift::runtime;
#ifdef SWIFT_STDLIB_SINGLE_THREADED_RUNTIME
SwiftTLSContext &SwiftTLSContext::get() {
static SwiftTLSContext TLSContext;
return TLSContext;
}
#elif SWIFT_TLS_HAS_RESERVED_PTHREAD_SPECIFIC
// Use the reserved TSD key if possible.
SwiftTLSContext &SwiftTLSContext::get() {
SwiftTLSContext *ctx = static_cast<SwiftTLSContext *>(
SWIFT_THREAD_GETSPECIFIC(SWIFT_RUNTIME_TLS_KEY));
if (ctx)
return *ctx;
static OnceToken_t setupToken;
SWIFT_ONCE_F(
setupToken,
[](void *) {
pthread_key_init_np(SWIFT_RUNTIME_TLS_KEY, [](void *pointer) {
delete static_cast<SwiftTLSContext *>(pointer);
});
},
nullptr);
ctx = new SwiftTLSContext();
SWIFT_THREAD_SETSPECIFIC(SWIFT_RUNTIME_TLS_KEY, ctx);
return *ctx;
}
#elif __has_feature(cxx_thread_local)
// Second choice is direct language support for thread-locals.
namespace {
static thread_local SwiftTLSContext TLSContext;
} // anonymous namespace
SwiftTLSContext &SwiftTLSContext::get() { return TLSContext; }
#else
// Use the platform thread-local data API.
static __swift_thread_key_t createSwiftThreadKey() {
__swift_thread_key_t key;
int result = SWIFT_THREAD_KEY_CREATE(&key, [](void *pointer) {
delete static_cast<SwiftTLSContext *>(pointer);
});
if (result != 0) {
fatalError(0, "couldn't create thread key for exclusivity: %s\n",
strerror(result));
}
return key;
}
static SwiftTLSContext &getTLSContext() {
static __swift_thread_key_t key = createSwiftThreadKey();
SwiftTLSContext *ctx =
static_cast<SwiftTLSContext *>(SWIFT_THREAD_GETSPECIFIC(key));
if (!ctx) {
ctx = new SwiftTLSContext();
SWIFT_THREAD_SETSPECIFIC(key, ctx);
}
return *ctx;
}
#endif