From 5eb8ce461ff596a0ba35e7ec7498056ef2e5b216 Mon Sep 17 00:00:00 2001
From: Yuta Saito <kateinoigakukun@gmail.com>
Date: Sun, 29 Aug 2021 18:07:28 +0000
Subject: [PATCH] [Concurrency] repair cooperative global executor

This patch guards some includes of libdispatch headers so that platforms
that doesn't support libdispatch can build cooperative executor runtime.
And fixed missing implementations for cooperative mode.
---
 stdlib/public/Concurrency/Executor.swift     |  2 ++
 stdlib/public/Concurrency/GlobalExecutor.cpp | 19 ++++++++++++++++++-
 stdlib/public/Concurrency/Task.cpp           |  6 ++++++
 stdlib/public/Concurrency/TaskGroup.cpp      |  2 ++
 stdlib/public/Concurrency/TaskPrivate.h      |  2 ++
 5 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/stdlib/public/Concurrency/Executor.swift b/stdlib/public/Concurrency/Executor.swift
index d4456fd6d7fa3..1daf120fee8fa 100644
--- a/stdlib/public/Concurrency/Executor.swift
+++ b/stdlib/public/Concurrency/Executor.swift
@@ -93,6 +93,7 @@ func _checkExpectedExecutor(_filenameStart: Builtin.RawPointer,
     _filenameStart, _filenameLength, _filenameIsASCII, _line, _executor)
 }
 
+#if !SWIFT_STDLIB_SINGLE_THREADED_RUNTIME
 // This must take a DispatchQueueShim, not something like AnyObject,
 // or else SILGen will emit a retain/release in unoptimized builds,
 // which won't work because DispatchQueues aren't actually
@@ -119,3 +120,4 @@ internal final class DispatchQueueShim: UnsafeSendable, SerialExecutor {
     return UnownedSerialExecutor(ordinary: self)
   }
 }
+#endif
\ No newline at end of file
diff --git a/stdlib/public/Concurrency/GlobalExecutor.cpp b/stdlib/public/Concurrency/GlobalExecutor.cpp
index 5fbdec4ac9f23..1e9214321b903 100644
--- a/stdlib/public/Concurrency/GlobalExecutor.cpp
+++ b/stdlib/public/Concurrency/GlobalExecutor.cpp
@@ -59,12 +59,15 @@
 #include "TaskPrivate.h"
 #include "Error.h"
 
+#if !SWIFT_CONCURRENCY_COOPERATIVE_GLOBAL_EXECUTOR
 #include <dispatch/dispatch.h>
 
 #if !defined(_WIN32)
 #include <dlfcn.h>
 #endif
 
+#endif
+
 using namespace swift;
 
 SWIFT_CC(swift)
@@ -180,7 +183,7 @@ void swift::donateThreadToGlobalExecutorUntil(bool (*condition)(void *),
   while (!condition(conditionContext)) {
     auto job = claimNextFromJobQueue();
     if (!job) return;
-    job->run(ExecutorRef::generic());
+    swift_job_run(job, ExecutorRef::generic());
   }
 }
 
@@ -405,21 +408,35 @@ void swift::swift_task_enqueueMainExecutor(Job *job) {
     swift_task_enqueueMainExecutorImpl(job);
 }
 
+#if !SWIFT_CONCURRENCY_COOPERATIVE_GLOBAL_EXECUTOR
 void swift::swift_task_enqueueOnDispatchQueue(Job *job,
                                               HeapObject *_queue) {
   JobPriority priority = job->getPriority();
   auto queue = reinterpret_cast<dispatch_queue_t>(_queue);
   dispatchEnqueue(queue, job, (dispatch_qos_class_t)priority, queue);
 }
+#endif
+
+#if SWIFT_CONCURRENCY_COOPERATIVE_GLOBAL_EXECUTOR
+static HeapObject _swift_mainExecutorIdentity;
+#endif
 
 ExecutorRef swift::swift_task_getMainExecutor() {
+#if SWIFT_CONCURRENCY_COOPERATIVE_GLOBAL_EXECUTOR
+  return ExecutorRef::forOrdinary(&_swift_mainExecutorIdentity, nullptr);
+#else
   return ExecutorRef::forOrdinary(
            reinterpret_cast<HeapObject*>(&_dispatch_main_q),
            _swift_task_getDispatchQueueSerialExecutorWitnessTable());
+#endif
 }
 
 bool ExecutorRef::isMainExecutor() const {
+#if SWIFT_CONCURRENCY_COOPERATIVE_GLOBAL_EXECUTOR
+  return Identity == &_swift_mainExecutorIdentity;
+#else
   return Identity == reinterpret_cast<HeapObject*>(&_dispatch_main_q);
+#endif
 }
 
 #define OVERRIDE_GLOBAL_EXECUTOR COMPATIBILITY_OVERRIDE
diff --git a/stdlib/public/Concurrency/Task.cpp b/stdlib/public/Concurrency/Task.cpp
index 860c0a831ccac..bc30b81103612 100644
--- a/stdlib/public/Concurrency/Task.cpp
+++ b/stdlib/public/Concurrency/Task.cpp
@@ -27,7 +27,9 @@
 #include "Debug.h"
 #include "Error.h"
 
+#if !SWIFT_CONCURRENCY_COOPERATIVE_GLOBAL_EXECUTOR
 #include <dispatch/dispatch.h>
+#endif
 
 #if !defined(_WIN32)
 #include <dlfcn.h>
@@ -242,12 +244,16 @@ static void destroyTask(SWIFT_CONTEXT HeapObject *obj) {
 }
 
 static ExecutorRef executorForEnqueuedJob(Job *job) {
+#if SWIFT_CONCURRENCY_COOPERATIVE_GLOBAL_EXECUTOR
+  return ExecutorRef::generic();
+#else
   void *jobQueue = job->SchedulerPrivate[Job::DispatchQueueIndex];
   if (jobQueue == DISPATCH_QUEUE_GLOBAL_EXECUTOR)
     return ExecutorRef::generic();
   else
     return ExecutorRef::forOrdinary(reinterpret_cast<HeapObject*>(jobQueue),
                     _swift_task_getDispatchQueueSerialExecutorWitnessTable());
+#endif
 }
 
 static void jobInvoke(void *obj, void *unused, uint32_t flags) {
diff --git a/stdlib/public/Concurrency/TaskGroup.cpp b/stdlib/public/Concurrency/TaskGroup.cpp
index 56dd88d91f9ef..e2ce5c0951ad2 100644
--- a/stdlib/public/Concurrency/TaskGroup.cpp
+++ b/stdlib/public/Concurrency/TaskGroup.cpp
@@ -34,7 +34,9 @@
 #include "queue" // TODO: remove and replace with usage of our mpsc queue
 #include <atomic>
 #include <assert.h>
+#if !SWIFT_CONCURRENCY_COOPERATIVE_GLOBAL_EXECUTOR
 #include <dispatch/dispatch.h>
+#endif
 
 #if !defined(_WIN32)
 #include <dlfcn.h>
diff --git a/stdlib/public/Concurrency/TaskPrivate.h b/stdlib/public/Concurrency/TaskPrivate.h
index 0984ac4b6a418..a605819e92133 100644
--- a/stdlib/public/Concurrency/TaskPrivate.h
+++ b/stdlib/public/Concurrency/TaskPrivate.h
@@ -112,12 +112,14 @@ void _swift_tsan_release(void *addr);
 /// executors.
 #define DISPATCH_QUEUE_GLOBAL_EXECUTOR (void *)1
 
+#if !defined(SWIFT_STDLIB_SINGLE_THREADED_RUNTIME)
 inline SerialExecutorWitnessTable *
 _swift_task_getDispatchQueueSerialExecutorWitnessTable() {
   extern SerialExecutorWitnessTable wtable
     SWIFT_ASM_LABEL_WITH_PREFIX("$ss17DispatchQueueShimCScfsWP");
   return &wtable;
 }
+#endif
 
 // ==== ------------------------------------------------------------------------