[Concurrency] Fix test failures, add struct layout checks.

We were missing a field in `SwiftJob`, which broke various things.  To
avoid that problem in future, this PR adds a set of static asserts to
check the layout of various structures and that we're using the same
values as well.

Also added some functions to the ABI, and fixed things so that if you
enable the debug logging the library still builds (there was an extra
`_` in `Actor.cpp` that caused a build failure).

Finally, renamed `Hooks.cpp` to `ConcurrencyHooks.cpp`.

rdar://135380149

Author: al45tair

stdlib/public/Concurrency/Actor.cpp

@@ -2240,7 +2240,7 @@ static void swift_task_enqueueImpl(Job *job, SerialExecutorRef serialExecutorRef
   }
   SWIFT_TASK_DEBUG_LOG("enqueue job %p on serial serialExecutor %p, taskExecutor = %p", job,
                        serialExecutorRef.getIdentity(),
-                       __taskExecutorRef.getIdentity());
+                       _taskExecutorRef.getIdentity());
 #endif
 
   assert(job && "no job provided");

stdlib/public/Concurrency/CMakeLists.txt

@@ -74,9 +74,10 @@ set(SWIFT_RUNTIME_CONCURRENCY_C_SOURCES
   AsyncLet.cpp
   Clock.cpp
   GlobalExecutor.cpp
-  Hooks.cpp
+  ConcurrencyHooks.cpp
   EmbeddedSupport.cpp
   Error.cpp
+  ExecutorChecks.cpp
   Setup.cpp
   Task.cpp
   TaskAlloc.cpp

stdlib/public/Concurrency/Hooks.cpp renamed to stdlib/public/Concurrency/ConcurrencyHooks.cpp

@@ -0,0 +1,67 @@
+///===--- ExecutorChecks.cpp - Static assertions to check struct layouts ---===///
+///
+/// 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
+///
+///===----------------------------------------------------------------------===///
+///
+/// This file is responsible for checking that the structures in ExecutorImpl.h
+/// are laid out exactly the same as those in the ABI headers.
+///
+///===----------------------------------------------------------------------===///
+
+#include "swift/Runtime/Concurrency.h"
+
+#include "swift/ABI/Executor.h"
+#include "swift/ABI/MetadataValues.h"
+#include "swift/ABI/Task.h"
+
+#include "ExecutorImpl.h"
+
+// JobFlags
+static_assert(sizeof(swift::JobFlags) == sizeof(SwiftJobFlags));
+
+// JobKind
+static_assert(sizeof(swift::JobKind) == sizeof(SwiftJobKind));
+static_assert((SwiftJobKind)swift::JobKind::Task == SwiftTaskJobKind);
+static_assert((SwiftJobKind)swift::JobKind::First_Reserved == SwiftFirstReservedJobKind);
+
+// JobPriority
+static_assert(sizeof(swift::JobPriority) == sizeof(SwiftJobPriority));
+static_assert((SwiftJobPriority)swift::JobPriority::UserInteractive
+              == SwiftUserInteractiveJobPriority);
+static_assert((SwiftJobPriority)swift::JobPriority::UserInteractive
+              == SwiftUserInteractiveJobPriority);
+static_assert((SwiftJobPriority)swift::JobPriority::UserInitiated
+              == SwiftUserInitiatedJobPriority);
+static_assert((SwiftJobPriority)swift::JobPriority::Default
+              == SwiftDefaultJobPriority);
+static_assert((SwiftJobPriority)swift::JobPriority::Utility
+              == SwiftUtilityJobPriority);
+static_assert((SwiftJobPriority)swift::JobPriority::Background
+              == SwiftBackgroundJobPriority);
+static_assert((SwiftJobPriority)swift::JobPriority::Unspecified
+              == SwiftUnspecifiedJobPriority);
+
+// Job (has additional fields not exposed via SwiftJob)
+static_assert(sizeof(swift::Job) >= sizeof(SwiftJob));
+static_assert(offsetof(swift::Job, metadata) == offsetof(SwiftJob, metadata));
+static_assert(offsetof(swift::Job, refCounts) == offsetof(SwiftJob, refCounts));
+static_assert(offsetof(swift::Job, SchedulerPrivate) == offsetof(SwiftJob, schedulerPrivate));
+static_assert(offsetof(swift::Job, SchedulerPrivate[0]) == offsetof(SwiftJob, schedulerPrivate[0]));
+static_assert(offsetof(swift::Job, SchedulerPrivate[1]) == offsetof(SwiftJob, schedulerPrivate[1]));
+static_assert(offsetof(swift::Job, Flags) == offsetof(SwiftJob, flags));
+
+// SerialExecutorRef
+static_assert(sizeof(swift::SerialExecutorRef) == sizeof(SwiftExecutorRef));
+
+// swift_clock_id
+static_assert((SwiftClockId)swift::swift_clock_id_continuous
+              == SwiftContinuousClock);
+static_assert((SwiftClockId)swift::swift_clock_id_suspending
+              == SwiftSuspendingClock);

stdlib/public/Concurrency/ExecutorChecks.cpp

@@ -93,6 +93,7 @@ static inline int swift_priority_getBucketIndex(SwiftJobPriority priority) {
 /// field may be freely used by the executor implementation.
 typedef struct {
   SwiftHeapMetadata const *__ptrauth_objc_isa_pointer metadata;
+  uintptr_t refCounts;
   void *schedulerPrivate[2];
   SwiftJobFlags flags;
 } __attribute__((aligned(2 * sizeof(void *)))) SwiftJob;

stdlib/public/Concurrency/ExecutorImpl.h

@@ -343,6 +343,12 @@ Added: _swift_task_invokeSwiftCheckIsolated
 Added: _swift_task_isMainExecutor
 Added: _swift_task_isMainExecutor_hook
 
+Added: __swift_task_isMainExecutor_c
+Added: _swift_task_donateThreadToGlobalExecutorUntil
+Added: _swift_task_donateThreadToGlobalExecutorUntil_hook
+Added: _swift_job_alloc
+Added: _swift_job_dealloc
+
 // Add property descriptors for static properties
 Added: _$sScM21sharedUnownedExecutorScevpZMV
 Added: _$sScM6sharedScMvpZMV

test/abi/macOS/arm64/concurrency.swift

@@ -344,6 +344,12 @@ Added: _swift_task_invokeSwiftCheckIsolated
 Added: _swift_task_isMainExecutor
 Added: _swift_task_isMainExecutor_hook
 
+Added: __swift_task_isMainExecutor_c
+Added: _swift_task_donateThreadToGlobalExecutorUntil
+Added: _swift_task_donateThreadToGlobalExecutorUntil_hook
+Added: _swift_job_alloc
+Added: _swift_job_dealloc
+
 // Add property descriptors for static properties
 Added: _$sScM21sharedUnownedExecutorScevpZMV
 Added: _$sScM6sharedScMvpZMV