Move swift_task_alloc/dealloc into the Concurrency library.

Also, rename them to follow the general namespacing scheme.

Author: rjmccall

include/swift/Runtime/Concurrency.h

@@ -21,6 +21,22 @@
 
 namespace swift {
 
+/// Allocate memory in a task.
+///
+/// This must be called synchronously with the task.
+///
+/// All allocations will be rounded to a multiple of MAX_ALIGNMENT.
+SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
+void *swift_task_alloc(AsyncTask *task, size_t size);
+
+/// Deallocate memory in a task.
+///
+/// The pointer provided must be the last pointer allocated on
+/// this task that has not yet been deallocated; that is, memory
+/// must be allocated and deallocated in a strict stack discipline.
+SWIFT_EXPORT_FROM(swift_Concurrency) SWIFT_CC(swift)
+void swift_task_dealloc(AsyncTask *task, void *ptr);
+
 /// Cancel a task and all of its child tasks.
 ///
 /// This can be called from any thread.

include/swift/Runtime/RuntimeFunctions.def

@@ -1461,17 +1461,17 @@ FUNCTION(GetTypeByMangledNameInContextInMetadataState,
               Int8PtrPtrTy),
          ATTRS(NoUnwind, ArgMemOnly))
 
-// void *swift_taskAlloc(SwiftTask *task, size_t size);
+// void *swift_task_alloc(AsyncTask *task, size_t size);
 FUNCTION(TaskAlloc,
-         swift_taskAlloc, SwiftCC,
+         swift_task_alloc, SwiftCC,
          ConcurrencyAvailability,
          RETURNS(Int8PtrTy),
          ARGS(SwiftTaskPtrTy, SizeTy),
          ATTRS(NoUnwind, ArgMemOnly))
 
-// void swift_taskDealloc(SwiftTask *task, void *ptr);
+// void swift_task_dealloc(AsyncTask *task, void *ptr);
 FUNCTION(TaskDealloc,
-         swift_taskDealloc, SwiftCC,
+         swift_task_dealloc, SwiftCC,
          ConcurrencyAvailability,
          RETURNS(VoidTy),
          ARGS(SwiftTaskPtrTy, Int8PtrTy),

stdlib/public/Concurrency/CMakeLists.txt

@@ -13,6 +13,7 @@
 add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   Actor.swift
   PartialAsyncTask.swift
+  TaskAlloc.cpp
   TaskStatus.cpp
   Mutex.cpp
 

stdlib/public/runtime/Concurrency.cpp renamed to stdlib/public/Concurrency/TaskAlloc.cpp

@@ -1,4 +1,4 @@
-//===------------ Concurrency.cpp - Swift Concurrency Support ------------===//
+//===--- TaskAlloc.cpp - Task-local stack allocator -----------------------===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -10,28 +10,22 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// Implementations of the concurrency runtime functions.
+// A task-local allocator that obeys a stack discipline.
 //
-// void *swift_taskAlloc(SwiftTask *task, size_t size);
-// void swift_taskDealloc(SwiftTask *task, void *ptr);
+// Because allocation is task-local, and there's at most one thread
+// running a task at once, no synchronization is required.
 //
 //===----------------------------------------------------------------------===//
 
-#include "../SwiftShims/Visibility.h"
-#include "swift/Runtime/Config.h"
-#include <cstddef>
+#include "swift/Runtime/Concurrency.h"
 #include <stdlib.h>
 
-struct SwiftTask;
+using namespace swift;
 
-SWIFT_RUNTIME_EXPORT
-SWIFT_CC(swift)
-void *swift_taskAlloc(SwiftTask *task, size_t size) {
+void *swift::swift_task_alloc(AsyncTask *task, size_t size) {
   return malloc(size);
 }
 
-SWIFT_RUNTIME_EXPORT
-SWIFT_CC(swift)
-void swift_taskDealloc(SwiftTask *task, void *ptr) {
+void swift::swift_task_dealloc(AsyncTask *task, void *ptr) {
   free(ptr);
 }

stdlib/public/Concurrency/TaskStatus.cpp

@@ -1,4 +1,4 @@
-//===--- Metadata.cpp - Swift Language ABI Metadata Support ---------------===//
+//===--- TaskStatus.cpp - Asynchronous task status tracking ---------------===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -10,7 +10,8 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// Routines for cancelling tasks.
+// Routines for maintaining and interacting with the current state of a
+// task, including tracking child tasks, deadlines, and cancellation.
 //
 //===----------------------------------------------------------------------===//
 

stdlib/public/runtime/CMakeLists.txt

@@ -31,7 +31,6 @@ set(swift_runtime_sources
     BackDeployment.cpp
     Casting.cpp
     CompatibilityOverride.cpp
-    Concurrency.cpp
     CygwinPort.cpp
     Demangle.cpp
     DynamicCast.cpp