Merge pull request #84528 from rjmccall/async-let-runtime-realism

Model async let begin/finish as builtins in SIL

Author: rjmccall

include/swift/ABI/MetadataValues.h

@@ -2910,9 +2910,9 @@ enum class TaskOptionRecordKind : uint8_t {
   InitialSerialExecutor = 0,
   /// Request a child task to be part of a specific task group.
   TaskGroup = 1,
-  /// DEPRECATED. AsyncLetWithBuffer is used instead.
+  /// UNUSED. AsyncLetWithBuffer is used instead.
   /// Request a child task for an 'async let'.
-  AsyncLet = 2,
+  // AsyncLet = 2,
   /// Request a child task for an 'async let'.
   AsyncLetWithBuffer = 3,
   /// Information about the result type of the task, used in embedded Swift.

include/swift/ABI/TaskOptions.h

@@ -166,25 +166,6 @@ class InitialSerialExecutorTaskOptionRecord : public TaskOptionRecord {
   }
 };
 
-/// DEPRECATED. AsyncLetWithBufferTaskOptionRecord is used instead.
-/// Task option to specify that the created task is for an 'async let'.
-class AsyncLetTaskOptionRecord : public TaskOptionRecord {
-  AsyncLet *asyncLet;
-
-public:
-  AsyncLetTaskOptionRecord(AsyncLet *asyncLet)
-    : TaskOptionRecord(TaskOptionRecordKind::AsyncLet),
-      asyncLet(asyncLet) {}
-
-  AsyncLet *getAsyncLet() const {
-    return asyncLet;
-  }
-
-  static bool classof(const TaskOptionRecord *record) {
-    return record->getKind() == TaskOptionRecordKind::AsyncLet;
-  }
-};
-
 class AsyncLetWithBufferTaskOptionRecord : public TaskOptionRecord {
   AsyncLet *asyncLet;
   void *resultBuffer;

include/swift/AST/Builtins.def

@@ -885,17 +885,7 @@ BUILTIN_MISC_OPERATION_WITH_SILGEN(GetCurrentAsyncTask, "getCurrentAsyncTask", "
 /// Cancel the given asynchronous task.
 BUILTIN_MISC_OPERATION_WITH_SILGEN(CancelAsyncTask, "cancelAsyncTask", "", Special)
 
-/// startAsyncLet()<T>: (
-///     __owned @escaping () async throws -> sending T
-/// ) -> Builtin.RawPointer
-///
-/// DEPRECATED. startAsyncLetWithLocalBuffer is used instead.
-///
-/// Create, initialize and start a new async-let and associated task.
-/// Returns an AsyncLet* that must be passed to endAsyncLet for destruction.
-BUILTIN_MISC_OPERATION(StartAsyncLet, "startAsyncLet", "", Special)
-
-/// startAsyncLetWithLocalBuffer()<T>: (
+/// startAsyncLetWithLocalBuffer: <T> (
 ///     __owned @escaping () async throws -> sending T,
 ///     _ resultBuf: Builtin.RawPointer
 /// ) -> Builtin.RawPointer
@@ -936,16 +926,11 @@ BUILTIN_MISC_OPERATION(FlowSensitiveSelfIsolation, "flowSensitiveSelfIsolation",
 BUILTIN_MISC_OPERATION(FlowSensitiveDistributedSelfIsolation,
                        "flowSensitiveDistributedSelfIsolation", "", Special)
 
-/// endAsyncLet(): (Builtin.RawPointer) -> Void
+/// finishAsyncLet(Builtin.RawPointer, Builtin.RawPointer) -> Void
 ///
-/// DEPRECATED. The swift_asyncLet_finish intrinsic and endAsyncLetLifetime
-/// builtin are used instead.
-///
-/// Ends and destroys an async-let.
-/// The ClosureLifetimeFixup pass adds a second operand to the builtin to
-/// ensure that optimizations keep the stack-allocated closure arguments alive
-/// until the endAsyncLet.
-BUILTIN_MISC_OPERATION_WITH_SILGEN(EndAsyncLet, "endAsyncLet", "", Special)
+/// End the scope of an async let. An async operation. Deallocates stack
+/// memory that was allocated by startAsyncLetWithLocalBuffer.
+BUILTIN_MISC_OPERATION(FinishAsyncLet, "finishAsyncLet", "", Special)
 
 /// endAsyncLetLifetime(): (Builtin.RawPointer) -> Void
 ///

include/swift/AST/Builtins.h

@@ -77,7 +77,7 @@ enum class OverloadedBuiltinKind : uint8_t {
 };
 
 /// BuiltinValueKind - The set of (possibly overloaded) builtin functions.
-enum class BuiltinValueKind {
+enum class BuiltinValueKind : unsigned {
   None = 0,
 #define BUILTIN(Id, Name, Attrs) Id,
 #include "swift/AST/Builtins.def"