Files
swift-mirror/stdlib/toolchain/Compatibility56/Concurrency/TaskLocal.cpp
Evan Wilde 543c6a6bdc Remove unused functions from 5.6 backdeploy
Removing
 - swift_task_localValueGetImpl
 - swift_task_localValuePopImpl
 - swift_task_localsCopyToImpl
 - swift_task_reportIllegalTaskLocalBindingWithinWithTaskGroupImpl

These static functions are not used or exported from the 5.6 backdeploy
library.
2022-10-19 22:59:09 -07:00

266 lines
8.8 KiB
C++

//===--- TaskLocal.cpp - Task Local Values --------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2020 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 <cstdint>
#include "swift/Runtime/Atomic.h"
#include "swift/Runtime/Casting.h"
#include "swift/Runtime/Portability.h"
#include "Concurrency/Threading/Mutex.h"
#include "Runtime/Threading/ThreadLocal.h"
#include "Runtime/Concurrency.h"
#include "Concurrency/TaskLocal.h"
#include "Concurrency/Task.h"
#include "Concurrency/Actor.h"
/* #include "Concurrency/Metadata.h" */
#include "Concurrency/TaskPrivate.h"
#include "llvm/ADT/PointerIntPair.h"
/* #include "TaskPrivate.h" */
#include <set>
#if defined(__APPLE__)
#include <asl.h>
#elif defined(__ANDROID__)
#include <android/log.h>
#endif
#if HAVE_PTHREAD_H
#include <pthread.h>
#endif
#if defined(_WIN32)
#include <io.h>
#include <handleapi.h>
#include <processthreadsapi.h>
#endif
using namespace swift;
// =============================================================================
/// An extremely silly class which exists to make pointer
/// default-initialization constexpr.
template <class T> struct Pointer {
T *Value;
constexpr Pointer() : Value(nullptr) {}
constexpr Pointer(T *value) : Value(value) {}
operator T *() const { return Value; }
T *operator->() const { return Value; }
};
/// THIS IS RUNTIME INTERNAL AND NOT ABI.
class FallbackTaskLocalStorage {
static SWIFT_RUNTIME_DECLARE_THREAD_LOCAL(
Pointer<TaskLocal::Storage>, Value,
SWIFT_CONCURRENCY_FALLBACK_TASK_LOCAL_STORAGE_KEY);
public:
static void set(TaskLocal::Storage *task) { Value.set(task); }
static TaskLocal::Storage *get() { return Value.get(); }
};
/// Define the thread-locals.
SWIFT_RUNTIME_DECLARE_THREAD_LOCAL(
Pointer<TaskLocal::Storage>, FallbackTaskLocalStorage::Value,
SWIFT_CONCURRENCY_FALLBACK_TASK_LOCAL_STORAGE_KEY);
// =============================================================================
// ==== Initialization ---------------------------------------------------------
void TaskLocal::Storage::initializeLinkParent(AsyncTask* task,
AsyncTask* parent) {
assert(!head && "initial task local storage was already initialized");
assert(parent && "parent must be provided to link to it");
head = TaskLocal::Item::createParentLink(task, parent);
}
TaskLocal::Item*
TaskLocal::Item::createParentLink(AsyncTask *task, AsyncTask *parent) {
size_t amountToAllocate = Item::itemSize(/*valueType*/nullptr);
void *allocation = _swift_task_alloc_specific(task, amountToAllocate);
Item *item = new(allocation) Item();
auto parentHead = parent->_private().Local.head;
if (parentHead) {
if (parentHead->isEmpty()) {
switch (parentHead->getNextLinkType()) {
case NextLinkType::IsParent:
// it has no values, and just points to its parent,
// therefore skip also skip pointing to that parent and point
// to whichever parent it was pointing to as well, it may be its
// immediate parent, or some super-parent.
item->next = reinterpret_cast<uintptr_t>(parentHead->getNext()) |
static_cast<uintptr_t>(NextLinkType::IsParent);
break;
case NextLinkType::IsNext:
if (parentHead->getNext()) {
assert(false && "empty taskValue head in parent task, yet parent's 'head' is `IsNext`, "
"this should not happen, as it implies the parent must have stored some value.");
} else {
// is terminal pointer
item->next = reinterpret_cast<uintptr_t>(parentHead->getNext());
}
break;
}
} else {
item->next = reinterpret_cast<uintptr_t>(parentHead) |
static_cast<uintptr_t>(NextLinkType::IsParent);
}
} else {
item->next = reinterpret_cast<uintptr_t>(parentHead);
}
return item;
}
TaskLocal::Item*
TaskLocal::Item::createLink(AsyncTask *task,
const HeapObject *key,
const Metadata *valueType) {
size_t amountToAllocate = Item::itemSize(valueType);
void *allocation = task ? _swift_task_alloc_specific(task, amountToAllocate)
: malloc(amountToAllocate);
Item *item = new (allocation) Item(key, valueType);
auto next = task ? task->_private().Local.head
: FallbackTaskLocalStorage::get()->head;
item->next = reinterpret_cast<uintptr_t>(next) |
static_cast<uintptr_t>(NextLinkType::IsNext);
return item;
}
void TaskLocal::Item::copyTo(AsyncTask *target) {
assert(target && "TaskLocal item attempt to copy to null target task!");
// 'parent' pointers are signified by null valueType.
// We must not copy parent pointers, but rather perform a deep copy of all values,
// as such, we skip parent pointers here entirely.
if (isParentPointer())
return;
auto item = Item::createLink(target, key, valueType);
valueType->vw_initializeWithCopy(item->getStoragePtr(), getStoragePtr());
/// A `copyTo` may ONLY be invoked BEFORE the task is actually scheduled,
/// so right now we can safely copy the value into the task without additional
/// synchronization.
target->_private().Local.head = item;
}
// =============================================================================
// ==== destroy ----------------------------------------------------------------
void TaskLocal::Item::destroy(AsyncTask *task) {
// otherwise it was task-local allocated, so we can safely destroy it right away
if (valueType) {
valueType->vw_destroy(getStoragePtr());
}
// if task is available, we must have used the task allocator to allocate this item,
// so we must deallocate it using the same. Otherwise, we must have used malloc.
if (task) _swift_task_dealloc_specific(task, this);
else free(this);
}
void TaskLocal::Storage::destroy(AsyncTask *task) {
auto item = head;
head = nullptr;
TaskLocal::Item *next;
while (item) {
auto linkType = item->getNextLinkType();
switch (linkType) {
case TaskLocal::NextLinkType::IsNext:
next = item->getNext();
item->destroy(task);
item = next;
break;
case TaskLocal::NextLinkType::IsParent:
// we're done here; as we must not proceed into the parent owned values.
// we do have to destroy the item pointing at the parent/edge itself though.
item->destroy(task);
return;
}
}
}
// =============================================================================
// ==== Task Local Storage: operations -----------------------------------------
void TaskLocal::Storage::pushValue(AsyncTask *task,
const HeapObject *key,
/* +1 */ OpaqueValue *value,
const Metadata *valueType) {
assert(value && "Task local value must not be nil");
auto item = Item::createLink(task, key, valueType);
valueType->vw_initializeWithTake(item->getStoragePtr(), value);
head = item;
}
bool TaskLocal::Storage::popValue(AsyncTask *task) {
assert(head && "attempted to pop value off empty task-local stack");
auto old = head;
head = head->getNext();
old->destroy(task);
/// if pointing at not-null next item, there are remaining bindings.
return head != nullptr;
}
OpaqueValue* TaskLocal::Storage::getValue(AsyncTask *task,
const HeapObject *key) {
assert(key && "TaskLocal key must not be null.");
auto item = head;
while (item) {
if (item->key == key) {
return item->getStoragePtr();
}
item = item->getNext();
}
return nullptr;
}
void TaskLocal::Storage::copyTo(AsyncTask *target) {
assert(target && "task must not be null when copying values into it");
assert(!(target->_private().Local.head) &&
"Task must not have any task-local values bound before copying into it");
// Set of keys for which we already have copied to the new task.
// We only ever need to copy the *first* encounter of any given key,
// because it is the most "specific"/"recent" binding and any other binding
// of a key does not matter for the target task as it will never be able to
// observe it.
std::set<const HeapObject*> copied = {};
auto item = head;
while (item) {
// we only have to copy an item if it is the most recent binding of a key.
// i.e. if we've already seen an item for this key, we can skip it.
if (copied.emplace(item->key).second) {
item->copyTo(target);
}
item = item->getNext();
}
}