[RemoteMirror][swift-inspect] Add a command to inspect the state of the concurrency runtime.

Most of the new inspection logic is in Remote Mirror. New code in swift-inspect calls the new Remote Mirror functions and formats the resulting information for display.

Specific Remote Mirror changes:

* Add a call to check if a given metadata is an actor.
* Add calls to get information about actors and tasks.
* Add a `readObj` call to MemoryReader that combines the read and the cast, greatly simplifying code chasing pointers in the remote process.
* Add a generalized facility to the C shims that can allocate a temporary object that remains valid until at least the next call, which is used to return various temporary arrays from the new calls. Remove the existing `lastString` and `lastChunks` member variables in favor of this new facility.

Swift-inspect changes:

* Add a new dump-concurrency command.
* Add a new `ConcurrencyDumper.swift` file with the implementation. The dumper needs to do some additional work with the results from Remote Mirror to build up the task tree and this keeps it all organized.
* Extend `Inspector` to query the target's threads and fetch each thread's current task.

Concurrency runtime changes:

* Add `_swift_concurrency_debug` variables pointing to the various future adapters. Remote Mirror uses these to provide a better view of a tasks's resume pointer.

rdar://85231338

include/swift/Reflection/ReflectionContext.h

@@ -101,6 +101,12 @@ class ReflectionContext
   std::vector<MemoryReader::ReadBytesResult> savedBuffers;
   std::vector<std::tuple<RemoteAddress, RemoteAddress>> imageRanges;
 
+  bool setupTargetPointers = false;
+  typename super::StoredPointer target_non_future_adapter = 0;
+  typename super::StoredPointer target_future_adapter = 0;
+  typename super::StoredPointer target_task_wait_throwing_resume_adapter = 0;
+  typename super::StoredPointer target_task_future_wait_resume_adapter = 0;
+
 public:
   using super::getBuilder;
   using super::readDemanglingForContextDescriptor;
@@ -137,6 +143,21 @@ public:
     std::vector<AsyncTaskAllocationChunk> Chunks;
   };
 
+  struct AsyncTaskInfo {
+    uint32_t JobFlags;
+    uint64_t TaskStatusFlags;
+    uint64_t Id;
+    StoredPointer RunJob;
+    StoredPointer AllocatorSlabPtr;
+    std::vector<StoredPointer> ChildTasks;
+    std::vector<StoredPointer> AsyncBacktraceFrames;
+  };
+
+  struct ActorInfo {
+    StoredSize Flags;
+    StoredPointer FirstJob;
+  };
+
   explicit ReflectionContext(std::shared_ptr<MemoryReader> reader)
     : super(std::move(reader), *this)
   {}
@@ -1067,6 +1088,31 @@ public:
     return dyn_cast_or_null<const RecordTypeInfo>(TypeInfo);
   }
 
+  bool metadataIsActor(StoredPointer MetadataAddress) {
+    auto Metadata = readMetadata(MetadataAddress);
+    if (!Metadata)
+      return false;
+
+    // Only classes can be actors.
+    if (Metadata->getKind() != MetadataKind::Class)
+      return false;
+
+    auto DescriptorAddress =
+        super::readAddressOfNominalTypeDescriptor(Metadata);
+    if (!DescriptorAddress)
+      return false;
+
+    auto DescriptorBytes =
+        getReader().readBytes(RemoteAddress(DescriptorAddress),
+                              sizeof(TargetTypeContextDescriptor<Runtime>));
+    if (!DescriptorBytes)
+      return false;
+    auto Descriptor =
+        reinterpret_cast<const TargetTypeContextDescriptor<Runtime> *>(
+            DescriptorBytes.get());
+    return Descriptor->getTypeContextDescriptorFlags().class_isActor();
+  }
+
   /// Iterate the protocol conformance cache tree rooted at NodePtr, calling
   /// Call with the type and protocol in each node.
   void iterateConformanceTree(StoredPointer NodePtr,
@@ -1378,22 +1424,179 @@ public:
     return {llvm::None, {Slab->Next, SlabSize, {Chunk}}};
   }
 
-  std::pair<llvm::Optional<std::string>, StoredPointer>
+  std::pair<llvm::Optional<std::string>, AsyncTaskInfo>
-  asyncTaskSlabPtr(StoredPointer AsyncTaskPtr) {
+  asyncTaskInfo(StoredPointer AsyncTaskPtr) {
-    using AsyncTask = AsyncTask<Runtime>;
+    auto AsyncTaskObj = readObj<AsyncTask<Runtime>>(AsyncTaskPtr);
-
-    auto AsyncTaskBytes =
-        getReader().readBytes(RemoteAddress(AsyncTaskPtr), sizeof(AsyncTask));
-    auto *AsyncTaskObj =
-        reinterpret_cast<const AsyncTask *>(AsyncTaskBytes.get());
     if (!AsyncTaskObj)
-      return {std::string("failure reading async task"), 0};
+      return {std::string("failure reading async task"), {}};
 
-    StoredPointer SlabPtr = AsyncTaskObj->PrivateStorage.Allocator.FirstSlab;
+    AsyncTaskInfo Info{};
-    return {llvm::None, SlabPtr};
+    Info.JobFlags = AsyncTaskObj->Flags;
+    Info.TaskStatusFlags = AsyncTaskObj->PrivateStorage.Status.Flags;
+    Info.Id =
+        AsyncTaskObj->Id | ((uint64_t)AsyncTaskObj->PrivateStorage.Id << 32);
+    Info.AllocatorSlabPtr = AsyncTaskObj->PrivateStorage.Allocator.FirstSlab;
+    Info.RunJob = getRunJob(AsyncTaskObj.get());
+
+    // Find all child tasks.
+    auto RecordPtr = AsyncTaskObj->PrivateStorage.Status.Record;
+    while (RecordPtr) {
+      auto RecordObj = readObj<TaskStatusRecord<Runtime>>(RecordPtr);
+      if (!RecordObj)
+        break;
+
+      // This cuts off high bits if our size_t doesn't match the target's. We
+      // only read the Kind bits which are at the bottom, so that's OK here.
+      // Beware of this when reading anything else.
+      TaskStatusRecordFlags Flags{RecordObj->Flags};
+      auto Kind = Flags.getKind();
+
+      StoredPointer ChildTask = 0;
+      if (Kind == TaskStatusRecordKind::ChildTask) {
+        auto RecordObj = readObj<ChildTaskStatusRecord<Runtime>>(RecordPtr);
+        if (RecordObj)
+          ChildTask = RecordObj->FirstChild;
+      } else if (Kind == TaskStatusRecordKind::TaskGroup) {
+        auto RecordObj = readObj<TaskGroupTaskStatusRecord<Runtime>>(RecordPtr);
+        if (RecordObj)
+          ChildTask = RecordObj->FirstChild;
+      }
+
+      while (ChildTask) {
+        Info.ChildTasks.push_back(ChildTask);
+
+        StoredPointer ChildFragmentAddr =
+            ChildTask + sizeof(AsyncTask<Runtime>);
+        auto ChildFragmentObj =
+            readObj<ChildFragment<Runtime>>(ChildFragmentAddr);
+        if (ChildFragmentObj)
+          ChildTask = ChildFragmentObj->NextChild;
+        else
+          ChildTask = 0;
+      }
+
+      RecordPtr = RecordObj->Parent;
+    }
+
+    // Walk the async backtrace if the task isn't running or cancelled.
+    // TODO: Use isEnqueued from https://github.com/apple/swift/pull/41088/ once
+    // that's available.
+    int IsCancelledFlag = 0x100;
+    int IsRunningFlag = 0x800;
+    if (!(AsyncTaskObj->PrivateStorage.Status.Flags & IsCancelledFlag) &&
+        !(AsyncTaskObj->PrivateStorage.Status.Flags & IsRunningFlag)) {
+      auto ResumeContext = AsyncTaskObj->ResumeContextAndReserved[0];
+      while (ResumeContext) {
+        auto ResumeContextObj = readObj<AsyncContext<Runtime>>(ResumeContext);
+        if (!ResumeContextObj)
+          break;
+        Info.AsyncBacktraceFrames.push_back(
+            stripSignedPointer(ResumeContextObj->ResumeParent));
+        ResumeContext = stripSignedPointer(ResumeContextObj->Parent);
+      }
+    }
+
+    return {llvm::None, Info};
+  }
+
+  std::pair<llvm::Optional<std::string>, ActorInfo>
+  actorInfo(StoredPointer ActorPtr) {
+    using DefaultActorImpl = DefaultActorImpl<Runtime>;
+
+    auto ActorObj = readObj<DefaultActorImpl>(ActorPtr);
+    if (!ActorObj)
+      return {std::string("failure reading actor"), {}};
+
+    ActorInfo Info{};
+    Info.Flags = ActorObj->Flags;
+
+    // Status is the low 3 bits of Flags. Status of 0 is Idle. Don't read
+    // FirstJob when idle.
+    auto Status = Info.Flags & 0x7;
+    if (Status != 0) {
+      // This is a JobRef which stores flags in the low bits.
+      Info.FirstJob = ActorObj->FirstJob & ~StoredPointer(0x3);
+    }
+    return {llvm::None, Info};
+  }
+
+  StoredPointer nextJob(StoredPointer JobPtr) {
+    using Job = Job<Runtime>;
+
+    auto JobBytes = getReader().readBytes(RemoteAddress(JobPtr), sizeof(Job));
+    auto *JobObj = reinterpret_cast<const Job *>(JobBytes.get());
+    if (!JobObj)
+      return 0;
+
+    // This is a JobRef which stores flags in the low bits.
+    return JobObj->SchedulerPrivate[0] & ~StoredPointer(0x3);
   }
 
 private:
+  // Get the most human meaningful "run job" function pointer from the task,
+  // like AsyncTask::getResumeFunctionForLogging does.
+  StoredPointer getRunJob(const AsyncTask<Runtime> *AsyncTaskObj) {
+    auto Fptr = stripSignedPointer(AsyncTaskObj->RunJob);
+
+    loadTargetPointers();
+    auto ResumeContextPtr = AsyncTaskObj->ResumeContextAndReserved[0];
+    if (target_non_future_adapter && Fptr == target_non_future_adapter) {
+      using Prefix = AsyncContextPrefix<Runtime>;
+      auto PrefixAddr = ResumeContextPtr - sizeof(Prefix);
+      auto PrefixBytes =
+          getReader().readBytes(RemoteAddress(PrefixAddr), sizeof(Prefix));
+      if (PrefixBytes) {
+        auto PrefixPtr = reinterpret_cast<const Prefix *>(PrefixBytes.get());
+        return stripSignedPointer(PrefixPtr->AsyncEntryPoint);
+      }
+    } else if (target_future_adapter && Fptr == target_future_adapter) {
+      using Prefix = FutureAsyncContextPrefix<Runtime>;
+      auto PrefixAddr = ResumeContextPtr - sizeof(Prefix);
+      auto PrefixBytes =
+          getReader().readBytes(RemoteAddress(PrefixAddr), sizeof(Prefix));
+      if (PrefixBytes) {
+        auto PrefixPtr = reinterpret_cast<const Prefix *>(PrefixBytes.get());
+        return stripSignedPointer(PrefixPtr->AsyncEntryPoint);
+      }
+    } else if ((target_task_wait_throwing_resume_adapter &&
+                Fptr == target_task_wait_throwing_resume_adapter) ||
+               (target_task_future_wait_resume_adapter &&
+                Fptr == target_task_future_wait_resume_adapter)) {
+      auto ContextBytes = getReader().readBytes(RemoteAddress(ResumeContextPtr),
+                                                sizeof(AsyncContext<Runtime>));
+      if (ContextBytes) {
+        auto ContextPtr =
+            reinterpret_cast<const AsyncContext<Runtime> *>(ContextBytes.get());
+        return stripSignedPointer(ContextPtr->ResumeParent);
+      }
+    }
+
+    return Fptr;
+  }
+
+  void loadTargetPointers() {
+    if (setupTargetPointers)
+      return;
+
+    auto getFunc = [&](const std::string &name) -> StoredPointer {
+      auto Symbol = getReader().getSymbolAddress(name);
+      if (!Symbol)
+        return 0;
+      auto Pointer = getReader().readPointer(Symbol, sizeof(StoredPointer));
+      if (!Pointer)
+        return 0;
+      return Pointer->getResolvedAddress().getAddressData();
+    };
+    target_non_future_adapter =
+        getFunc("_swift_concurrency_debug_non_future_adapter");
+    target_future_adapter = getFunc("_swift_concurrency_debug_future_adapter");
+    target_task_wait_throwing_resume_adapter =
+        getFunc("_swift_concurrency_debug_task_wait_throwing_resume_adapter");
+    target_task_future_wait_resume_adapter =
+        getFunc("_swift_concurrency_debug_task_future_wait_resume_adapter");
+    setupTargetPointers = true;
+  }
+
   const TypeInfo *
   getClosureContextInfo(StoredPointer Context, const ClosureContextInfo &Info,
                         remote::TypeInfoProvider *ExternalTypeInfo) {
@@ -1615,6 +1818,11 @@ private:
 
     return llvm::None;
   }
+
+  template <typename T>
+  MemoryReader::ReadObjResult<T> readObj(StoredPointer Ptr) {
+    return getReader().template readObj<T>(RemoteAddress(Ptr));
+  }
 };
 
 } // end namespace reflection

include/swift/Reflection/RuntimeInternals.h

@@ -75,7 +75,7 @@ struct Job {
   uint32_t Flags;
   uint32_t Id;
   typename Runtime::StoredPointer Reserved[2];
-  typename Runtime::StoredPointer RunJob;
+  typename Runtime::StoredSignedPointer RunJob;
 };
 
 template <typename Runtime>
@@ -104,6 +104,8 @@ struct AsyncTaskPrivateStorage {
   ActiveTaskStatus<Runtime> Status;
   StackAllocator<Runtime> Allocator;
   typename Runtime::StoredPointer Local;
+  typename Runtime::StoredPointer ExclusivityAccessSet[2];
+  uint32_t Id;
 };
 
 template <typename Runtime>
@@ -112,7 +114,61 @@ struct AsyncTask: Job<Runtime> {
   typename Runtime::StoredPointer ResumeContextAndReserved[
     sizeof(typename Runtime::StoredPointer) == 8 ? 2 : 1];
 
-  AsyncTaskPrivateStorage<Runtime> PrivateStorage;
+  union {
+    AsyncTaskPrivateStorage<Runtime> PrivateStorage;
+    typename Runtime::StoredPointer PrivateStorageRaw[14];
+  };
+};
+
+template <typename Runtime>
+struct AsyncContext {
+  typename Runtime::StoredSignedPointer Parent;
+  typename Runtime::StoredSignedPointer ResumeParent;
+  uint32_t Flags;
+};
+
+template <typename Runtime>
+struct AsyncContextPrefix {
+  typename Runtime::StoredSignedPointer AsyncEntryPoint;
+  typename Runtime::StoredPointer ClosureContext;
+  typename Runtime::StoredPointer ErrorResult;
+};
+
+template <typename Runtime>
+struct FutureAsyncContextPrefix {
+  typename Runtime::StoredPointer IndirectResult;
+  typename Runtime::StoredSignedPointer AsyncEntryPoint;
+  typename Runtime::StoredPointer ClosureContext;
+  typename Runtime::StoredPointer ErrorResult;
+};
+
+template <typename Runtime>
+struct DefaultActorImpl {
+  HeapObject<Runtime> HeapObject;
+  typename Runtime::StoredPointer FirstJob;
+  typename Runtime::StoredSize Flags;
+};
+
+template <typename Runtime>
+struct TaskStatusRecord {
+  typename Runtime::StoredSize Flags;
+  typename Runtime::StoredPointer Parent;
+};
+
+template <typename Runtime>
+struct ChildTaskStatusRecord : TaskStatusRecord<Runtime> {
+  typename Runtime::StoredPointer FirstChild;
+};
+
+template <typename Runtime>
+struct TaskGroupTaskStatusRecord : TaskStatusRecord<Runtime> {
+  typename Runtime::StoredPointer FirstChild;
+};
+
+template <typename Runtime>
+struct ChildFragment {
+  typename Runtime::StoredPointer Parent;
+  typename Runtime::StoredPointer NextChild;
 };
 
 } // end namespace reflection

include/swift/Remote/MemoryReader.h

@@ -40,6 +40,10 @@ public:
   using ReadBytesResult =
       std::unique_ptr<const void, std::function<void(const void *)>>;
 
+  template <typename T>
+  using ReadObjResult =
+      std::unique_ptr<const T, std::function<void(const void *)>>;
+
   virtual bool queryDataLayout(DataLayoutQueryType type, void *inBuffer,
                                void *outBuffer) = 0;
 
@@ -90,6 +94,15 @@ public:
     return true;
   }
 
+  template <typename T>
+  ReadObjResult<T> readObj(RemoteAddress address) {
+    auto bytes = readBytes(address, sizeof(T));
+    auto deleter = bytes.get_deleter();
+    auto ptr = bytes.get();
+    bytes.release();
+    return ReadObjResult<T>(reinterpret_cast<const T *>(ptr), deleter);
+  }
+
   /// Attempts to read 'size' bytes from the given address in the remote process.
   ///
   /// Returns a pointer to the requested data and a function that must be called to

include/swift/SwiftRemoteMirror/SwiftRemoteMirror.h

@@ -151,6 +151,11 @@ swift_reflection_metadataNominalTypeDescriptor(SwiftReflectionContextRef Context
 																							 swift_reflection_ptr_t Metadata);
 
 
+SWIFT_REMOTE_MIRROR_LINKAGE
+int
+swift_reflection_metadataIsActor(SwiftReflectionContextRef ContextRef,
+                                 swift_reflection_ptr_t Metadata);
+
 /// Returns an opaque type reference for a class or closure context
 /// instance pointer, or NULL if one can't be constructed.
 ///
@@ -435,6 +440,21 @@ swift_async_task_slab_allocations_return_t
 swift_reflection_asyncTaskSlabAllocations(SwiftReflectionContextRef ContextRef,
                                           swift_reflection_ptr_t SlabPtr);
 
+SWIFT_REMOTE_MIRROR_LINKAGE
+swift_async_task_info_t
+swift_reflection_asyncTaskInfo(SwiftReflectionContextRef ContextRef,
+                               swift_reflection_ptr_t AsyncTaskPtr);
+
+SWIFT_REMOTE_MIRROR_LINKAGE
+swift_actor_info_t
+swift_reflection_actorInfo(SwiftReflectionContextRef ContextRef,
+                           swift_reflection_ptr_t ActorPtr);
+
+SWIFT_REMOTE_MIRROR_LINKAGE
+swift_reflection_ptr_t
+swift_reflection_nextJob(SwiftReflectionContextRef ContextRef,
+                         swift_reflection_ptr_t JobPtr);
+
 #ifdef __cplusplus
 } // extern "C"
 #endif

include/swift/SwiftRemoteMirror/SwiftRemoteMirrorTypes.h

@@ -225,6 +225,35 @@ typedef struct swift_async_task_slab_allocations_return {
   swift_async_task_allocation_chunk_t *Chunks;
 } swift_async_task_slab_allocations_return_t;
 
+typedef struct swift_async_task_info {
+  /// On failure, a pointer to a string describing the error. On success, NULL.
+  /// This pointer remains valid until the next
+  /// swift_reflection call on the given context.
+  const char *Error;
+
+  uint32_t JobFlags;
+  uint64_t TaskStatusFlags;
+  uint64_t Id;
+  swift_reflection_ptr_t RunJob;
+  swift_reflection_ptr_t AllocatorSlabPtr;
+
+  unsigned ChildTaskCount;
+  swift_reflection_ptr_t *ChildTasks;
+
+  unsigned AsyncBacktraceFramesCount;
+  swift_reflection_ptr_t *AsyncBacktraceFrames;
+} swift_async_task_info_t;
+
+typedef struct swift_actor_info {
+  /// On failure, a pointer to a string describing the error. On success, NULL.
+  /// This pointer remains valid until the next
+  /// swift_reflection call on the given context.
+  const char *Error;
+
+  uint64_t Flags;
+  swift_reflection_ptr_t FirstJob;
+} swift_actor_info_t;
+
 /// An opaque pointer to a context which maintains state and
 /// caching of reflection structure for heap instances.
 typedef struct SwiftReflectionContext *SwiftReflectionContextRef;

stdlib/public/Concurrency/Debug.h

@@ -36,6 +36,15 @@ const void *const _swift_concurrency_debug_asyncTaskMetadata;
 SWIFT_EXPORT_FROM(swift_Concurrency)
 const void *const _swift_concurrency_debug_asyncTaskSlabMetadata;
 
+SWIFT_EXPORT_FROM(swift_Concurrency)
+const void *const _swift_concurrency_debug_non_future_adapter;
+SWIFT_EXPORT_FROM(swift_Concurrency)
+const void *const _swift_concurrency_debug_future_adapter;
+SWIFT_EXPORT_FROM(swift_Concurrency)
+const void *const _swift_concurrency_debug_task_wait_throwing_resume_adapter;
+SWIFT_EXPORT_FROM(swift_Concurrency)
+const void *const _swift_concurrency_debug_task_future_wait_resume_adapter;
+
 } // namespace swift
 
 #endif

stdlib/public/Concurrency/Task.cpp

@@ -450,6 +450,17 @@ task_future_wait_resume_adapter(SWIFT_ASYNC_CONTEXT AsyncContext *_context) {
   return _context->ResumeParent(_context->Parent);
 }
 
+const void *const swift::_swift_concurrency_debug_non_future_adapter =
+    reinterpret_cast<void *>(non_future_adapter);
+const void *const swift::_swift_concurrency_debug_future_adapter =
+    reinterpret_cast<void *>(future_adapter);
+const void
+    *const swift::_swift_concurrency_debug_task_wait_throwing_resume_adapter =
+        reinterpret_cast<void *>(task_wait_throwing_resume_adapter);
+const void
+    *const swift::_swift_concurrency_debug_task_future_wait_resume_adapter =
+        reinterpret_cast<void *>(task_future_wait_resume_adapter);
+
 const void *AsyncTask::getResumeFunctionForLogging() {
   if (ResumeTask == non_future_adapter) {
     auto asyncContextPrefix = reinterpret_cast<AsyncContextPrefix *>(

stdlib/public/SwiftRemoteMirror/CMakeLists.txt

@@ -12,6 +12,7 @@ if(SWIFT_BUILD_DYNAMIC_STDLIB)
                              ${SWIFT_RUNTIME_LINK_FLAGS}
                            INCORPORATE_OBJECT_LIBRARIES swiftLLVMSupport
                            SWIFT_COMPILE_FLAGS ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
+                           DARWIN_INSTALL_NAME_DIR "${SWIFTLIB_DARWIN_INSTALL_NAME_DIR}"
                            INSTALL_IN_COMPONENT
                              swift-remote-mirror)
 endif()

stdlib/public/SwiftRemoteMirror/SwiftRemoteMirror.cpp

@@ -47,8 +47,8 @@ struct SwiftReflectionContext {
   NativeReflectionContext *nativeContext;
   std::vector<std::function<void()>> freeFuncs;
   std::vector<std::tuple<swift_addr_t, swift_addr_t>> dataSegments;
-  std::string lastString;
+
-  std::vector<swift_async_task_allocation_chunk_t> lastChunks;
+  std::function<void(void)> freeTemporaryAllocation = [] {};
 
   SwiftReflectionContext(MemoryReaderImpl impl) {
     auto Reader = std::make_shared<CMemoryReader>(impl);
@@ -56,10 +56,38 @@ struct SwiftReflectionContext {
   }
   
   ~SwiftReflectionContext() {
+    freeTemporaryAllocation();
     delete nativeContext;
     for (auto f : freeFuncs)
       f();
   }
+
+  // Allocate a single temporary object that will stay allocated until the next
+  // call to this method, or until the context is destroyed.
+  template <typename T>
+  T *allocateTemporaryObject() {
+    freeTemporaryAllocation();
+    T *obj = new T;
+    freeTemporaryAllocation = [obj] { delete obj; };
+    return obj;
+  }
+
+  // Allocate a single temporary object that will stay allocated until the next
+  // call to allocateTemporaryObject, or until the context is destroyed. Does
+  // NOT free any existing objects created with allocateTemporaryObject or
+  // allocateSubsequentTemporaryObject. Use to allocate additional objects after
+  // a call to allocateTemporaryObject when muliple objects are needed
+  // simultaneously.
+  template <typename T>
+  T *allocateSubsequentTemporaryObject() {
+    T *obj = new T;
+    auto oldFree = freeTemporaryAllocation;
+    freeTemporaryAllocation = [obj, oldFree] {
+      delete obj;
+      oldFree();
+    };
+    return obj;
+  }
 };
 
 
@@ -297,6 +325,12 @@ swift_reflection_metadataNominalTypeDescriptor(SwiftReflectionContextRef Context
   return Context->nominalTypeDescriptorFromMetadata(MetadataAddress);
 }
 
+int swift_reflection_metadataIsActor(SwiftReflectionContextRef ContextRef,
+                                     swift_reflection_ptr_t Metadata) {
+  auto Context = ContextRef->nativeContext;
+  return Context->metadataIsActor(Metadata);
+}
+
 swift_typeref_t
 swift_reflection_typeRefForInstance(SwiftReflectionContextRef ContextRef,
                                     uintptr_t Object) {
@@ -505,8 +539,9 @@ static swift_layout_kind_t convertAllocationChunkKind(
 static const char *returnableCString(SwiftReflectionContextRef ContextRef,
                                       llvm::Optional<std::string> String) {
   if (String) {
-    ContextRef->lastString = *String;
+    auto *TmpStr = ContextRef->allocateTemporaryObject<std::string>();
-    return ContextRef->lastString.c_str();
+    *TmpStr = *String;
+    return TmpStr->c_str();
   }
   return nullptr;
 }
@@ -782,14 +817,10 @@ const char *swift_reflection_iterateMetadataAllocationBacktraces(
 swift_async_task_slab_return_t
 swift_reflection_asyncTaskSlabPointer(SwiftReflectionContextRef ContextRef,
                                       swift_reflection_ptr_t AsyncTaskPtr) {
-  auto Context = ContextRef->nativeContext;
+  auto Info = swift_reflection_asyncTaskInfo(ContextRef, AsyncTaskPtr);
-  llvm::Optional<std::string> Error;
-  NativeReflectionContext::StoredPointer SlabPtr;
-  std::tie(Error, SlabPtr) = Context->asyncTaskSlabPtr(AsyncTaskPtr);
-
   swift_async_task_slab_return_t Result = {};
-  Result.Error = returnableCString(ContextRef, Error);
+  Result.Error = Info.Error;
-  Result.SlabPtr = SlabPtr;
+  Result.SlabPtr = Info.AllocatorSlabPtr;
   return Result;
 }
 
@@ -802,23 +833,88 @@ swift_reflection_asyncTaskSlabAllocations(SwiftReflectionContextRef ContextRef,
   std::tie(Error, Info) = Context->asyncTaskSlabAllocations(SlabPtr);
 
   swift_async_task_slab_allocations_return_t Result = {};
-  Result.Error = returnableCString(ContextRef, Error);
+  if (Result.Error) {
+    Result.Error = returnableCString(ContextRef, Error);
+    return Result;
+  }
 
   Result.NextSlab = Info.NextSlab;
   Result.SlabSize = Info.SlabSize;
 
-  ContextRef->lastChunks.clear();
+  auto *Chunks = ContextRef->allocateTemporaryObject<
-  ContextRef->lastChunks.reserve(Info.Chunks.size());
+      std::vector<swift_async_task_allocation_chunk_t>>();
+  Chunks->reserve(Info.Chunks.size());
   for (auto &Chunk : Info.Chunks) {
     swift_async_task_allocation_chunk_t ConvertedChunk;
     ConvertedChunk.Start = Chunk.Start;
     ConvertedChunk.Length = Chunk.Length;
     ConvertedChunk.Kind = convertAllocationChunkKind(Chunk.Kind);
-    ContextRef->lastChunks.push_back(ConvertedChunk);
+    Chunks->push_back(ConvertedChunk);
   }
 
-  Result.ChunkCount = ContextRef->lastChunks.size();
+  Result.ChunkCount = Chunks->size();
-  Result.Chunks = ContextRef->lastChunks.data();
+  Result.Chunks = Chunks->data();
 
   return Result;
 }
+
+swift_async_task_info_t
+swift_reflection_asyncTaskInfo(SwiftReflectionContextRef ContextRef,
+                               swift_reflection_ptr_t AsyncTaskPtr) {
+  auto Context = ContextRef->nativeContext;
+  llvm::Optional<std::string> Error;
+  NativeReflectionContext::AsyncTaskInfo TaskInfo;
+  std::tie(Error, TaskInfo) = Context->asyncTaskInfo(AsyncTaskPtr);
+
+  swift_async_task_info_t Result = {};
+  if (Error) {
+    Result.Error = returnableCString(ContextRef, Error);
+    return Result;
+  }
+  Result.JobFlags = TaskInfo.JobFlags;
+  Result.TaskStatusFlags = TaskInfo.TaskStatusFlags;
+  Result.Id = TaskInfo.Id;
+  Result.RunJob = TaskInfo.RunJob;
+  Result.AllocatorSlabPtr = TaskInfo.AllocatorSlabPtr;
+
+  auto *ChildTasks =
+      ContextRef
+          ->allocateTemporaryObject<std::vector<swift_reflection_ptr_t>>();
+  std::copy(TaskInfo.ChildTasks.begin(), TaskInfo.ChildTasks.end(),
+            std::back_inserter(*ChildTasks));
+  Result.ChildTaskCount = ChildTasks->size();
+  Result.ChildTasks = ChildTasks->data();
+
+  auto *AsyncBacktraceFrames = ContextRef->allocateSubsequentTemporaryObject<
+      std::vector<swift_reflection_ptr_t>>();
+  std::copy(TaskInfo.AsyncBacktraceFrames.begin(),
+            TaskInfo.AsyncBacktraceFrames.end(),
+            std::back_inserter(*AsyncBacktraceFrames));
+  Result.AsyncBacktraceFramesCount = AsyncBacktraceFrames->size();
+  Result.AsyncBacktraceFrames = AsyncBacktraceFrames->data();
+
+  return Result;
+}
+
+swift_actor_info_t
+swift_reflection_actorInfo(SwiftReflectionContextRef ContextRef,
+                           swift_reflection_ptr_t ActorPtr) {
+  auto Context = ContextRef->nativeContext;
+  llvm::Optional<std::string> Error;
+  NativeReflectionContext::ActorInfo TaskInfo;
+  std::tie(Error, TaskInfo) = Context->actorInfo(ActorPtr);
+
+  swift_actor_info_t Result = {};
+  Result.Error = returnableCString(ContextRef, Error);
+  Result.Flags = TaskInfo.Flags;
+  Result.FirstJob = TaskInfo.FirstJob;
+
+  return Result;
+}
+
+swift_reflection_ptr_t
+swift_reflection_nextJob(SwiftReflectionContextRef ContextRef,
+                         swift_reflection_ptr_t JobPtr) {
+  auto Context = ContextRef->nativeContext;
+  return Context->nextJob(JobPtr);
+}

test/stdlib/symbol-visibility-linux.test-sh

@@ -44,6 +44,7 @@
 // RUN:             -e _ZNSt6vectorIjSaIjEE13_M_insert_auxIJRKjEEEvN9__gnu_cxx17__normal_iteratorIPjS1_EEDpOT_ \
 // RUN:             -e _ZNSt6vectorIjSaIjEE13_M_insert_auxIJjEEEvN9__gnu_cxx17__normal_iteratorIPjS1_EEDpOT_ \
 // RUN:             -e _ZNSt6vectorIjSaIjEE17_M_realloc_insertIJjEEEvN9__gnu_cxx17__normal_iteratorIPjS1_EEDpOT_ \
+// RUN:             -e _ZNSt6vectorImSaImEE17_M_realloc_insertIJRKmEEEvN9__gnu_cxx17__normal_iteratorIPmS1_EEDpOT_ \
 // RUN:             -e _ZNSt6vectorISt10unique_ptrIKvSt8functionIFvPS1_EEESaIS6_EE19_M_emplace_back_auxIJS6_EEEvDpOT_ \
 // RUN:             -e _ZNSt6vectorISt10unique_ptrIKvSt8functionIFvPS1_EEESaIS6_EE17_M_realloc_insertIJS6_EEEvN9__gnu_cxx17__normal_iteratorIPS6_S8_EEDpOT_ \
 // RUN:             -e _ZNSt10_HashtableImSt4pairIKmSt10unique_ptrIKvSt8functionIFvPS3_EEEESaIS9_ENSt8__detail10_Select1stESt8equal_toImESt4hashImENSB_18_Mod_range_hashingENSB_20_Default_ranged_hashENSB_20_Prime_rehash_policyENSB_17_Hashtable_traitsILb0ELb0ELb1EEEE10_M_emplaceIJS0_ImS8_EEEES0_INSB_14_Node_iteratorIS9_Lb0ELb0EEEbESt17integral_constantIbLb1EEDpOT_ \

tools/swift-inspect/Sources/swift-inspect/DumpConcurrency.swift

@@ -0,0 +1,401 @@
+import SwiftRemoteMirror
+
+func dumpConcurrency(
+  context: SwiftReflectionContextRef,
+  inspector: Inspector
+) throws {
+  let dumper = ConcurrencyDumper(context: context, inspector: inspector)
+  dumper.dumpTasks()
+  dumper.dumpActors()
+  dumper.dumpThreads()
+}
+
+fileprivate class ConcurrencyDumper {
+  let context: SwiftReflectionContextRef
+  let inspector: Inspector
+  let jobMetadata: swift_reflection_ptr_t?
+  let taskMetadata: swift_reflection_ptr_t?
+
+  struct TaskInfo {
+    var address: swift_reflection_ptr_t
+    var jobFlags: UInt32
+    var taskStatusFlags: UInt64
+    var id: UInt64
+    var runJob: swift_reflection_ptr_t
+    var allocatorSlabPtr: swift_reflection_ptr_t
+    var allocatorTotalSize: Int
+    var allocatorTotalChunks: Int
+    var childTasks: [swift_reflection_ptr_t]
+    var asyncBacktrace: [swift_reflection_ptr_t]
+    var parent: swift_reflection_ptr_t?
+  }
+
+  struct HeapInfo {
+    var tasks: [swift_reflection_ptr_t] = []
+    var jobs: [swift_reflection_ptr_t] = []
+    var actors: [swift_reflection_ptr_t] = []
+  }
+
+  lazy var heapInfo: HeapInfo = gatherHeapInfo()
+
+  lazy var threadCurrentTasks = inspector.threadCurrentTasks().filter{ $0.currentTask != 0 }
+
+  lazy var tasks: [swift_reflection_ptr_t: TaskInfo] = gatherTasks()
+
+  var actors: [swift_reflection_ptr_t] {
+    heapInfo.actors
+  }
+
+  var metadataIsActorCache: [swift_reflection_ptr_t: Bool] = [:]
+  var metadataNameCache: [swift_reflection_ptr_t: String?] = [:]
+
+  init(context: SwiftReflectionContextRef, inspector: Inspector) {
+    self.context = context
+    self.inspector = inspector
+
+    func getMetadata(symbolName: String) -> swift_reflection_ptr_t? {
+      let addr = inspector.getAddr(symbolName: symbolName)
+      if let ptr = inspector.read(address: addr, size: MemoryLayout<UInt>.size) {
+        return swift_reflection_ptr_t(ptr.load(as: UInt.self))
+      }
+      return nil
+    }
+    jobMetadata = getMetadata(symbolName: "_swift_concurrency_debug_jobMetadata")
+    taskMetadata = getMetadata(symbolName: "_swift_concurrency_debug_asyncTaskMetadata")
+  }
+
+  func gatherHeapInfo() -> HeapInfo {
+    var result = HeapInfo()
+    
+    inspector.enumerateMallocs { (pointer, size) in
+      let metadata = swift_reflection_ptr_t(swift_reflection_metadataForObject(context, UInt(pointer)))
+      if metadata == jobMetadata {
+        result.jobs.append(pointer)
+      } else if metadata == taskMetadata {
+        result.tasks.append(pointer)
+      } else if isActorMetadata(metadata) {
+        result.actors.append(pointer)
+      }
+    }
+
+    return result
+  }
+
+  func gatherTasks() -> [swift_reflection_ptr_t: TaskInfo] {
+    var map: [swift_reflection_ptr_t: TaskInfo] = [:]
+    var tasksToScan: Set<swift_reflection_ptr_t> = []
+    tasksToScan.formUnion(heapInfo.tasks)
+    tasksToScan.formUnion(threadCurrentTasks.map{ $0.currentTask }.filter{ $0 != 0 })
+
+    while !tasksToScan.isEmpty {
+      let taskToScan = tasksToScan.removeFirst()
+      if let info = info(forTask: taskToScan) {
+        map[taskToScan] = info
+        for child in info.childTasks {
+          let childMetadata = swift_reflection_metadataForObject(context, UInt(child))
+          if let taskMetadata = taskMetadata, childMetadata != taskMetadata {
+            print("Inconsistent data detected! Child task \(hex: child) has unknown metadata \(hex: taskMetadata)")
+          }
+          if map[child] == nil {
+            tasksToScan.insert(child)
+          }
+        }
+      }
+    }
+
+    for (task, info) in map {
+      for child in info.childTasks {
+        map[child]?.parent = task
+      }
+    }
+
+    return map
+  }
+
+  func isActorMetadata(_ metadata: swift_reflection_ptr_t) -> Bool {
+    if let cached = metadataIsActorCache[metadata] {
+      return cached
+    }
+    let result = swift_reflection_metadataIsActor(context, metadata) != 0
+    metadataIsActorCache[metadata] = result
+    return result
+  }
+
+  func name(metadata: swift_reflection_ptr_t) -> String? {
+    if let cached = metadataNameCache[metadata] {
+      return cached
+    }
+
+    let name = context.name(metadata: metadata)
+    metadataNameCache[metadata] = name
+    return name
+  }
+
+  func info(forTask task: swift_reflection_ptr_t) -> TaskInfo? {
+    let reflectionInfo = swift_reflection_asyncTaskInfo(context, task)
+    if let error = reflectionInfo.Error {
+      print("Error getting info for async task \(hex: task): \(String(cString: error))")
+      return nil
+    }
+
+    // These arrays are temporary pointers which we must copy out before we call
+    // into Remote Mirror again.
+    let children = Array(UnsafeBufferPointer(
+        start: reflectionInfo.ChildTasks,
+        count: Int(reflectionInfo.ChildTaskCount)))
+    let asyncBacktraceFrames = Array(UnsafeBufferPointer(
+        start: reflectionInfo.AsyncBacktraceFrames,
+        count: Int(reflectionInfo.AsyncBacktraceFramesCount)))
+
+    var allocatorSlab = reflectionInfo.AllocatorSlabPtr
+    var allocatorTotalSize = 0
+    var allocatorTotalChunks = 0
+    while allocatorSlab != 0 {
+      let allocations = swift_reflection_asyncTaskSlabAllocations(context,
+                                                                  allocatorSlab)
+      guard allocations.Error == nil else { break }
+      allocatorTotalSize += Int(allocations.SlabSize)
+      allocatorTotalChunks += Int(allocations.ChunkCount)
+
+      allocatorSlab = allocations.NextSlab
+    }
+
+    return TaskInfo(
+      address: task,
+      jobFlags: reflectionInfo.JobFlags,
+      taskStatusFlags: reflectionInfo.TaskStatusFlags,
+      id: reflectionInfo.Id,
+      runJob: reflectionInfo.RunJob,
+      allocatorSlabPtr: reflectionInfo.AllocatorSlabPtr,
+      allocatorTotalSize: allocatorTotalSize,
+      allocatorTotalChunks: allocatorTotalChunks,
+      childTasks: children,
+      asyncBacktrace: asyncBacktraceFrames
+    )
+  }
+
+  func taskHierarchy() -> [(level: Int, lastChild: Bool, task: TaskInfo)] {
+    var hierarchy: [(level: Int, lastChild: Bool, task: TaskInfo)] = []
+
+    let topLevelTasks = tasks.values.filter{ $0.parent == nil }
+    for top in topLevelTasks.sorted(by: { $0.id < $1.id }) {
+      var stack: [(index: Int, task: TaskInfo)] = [(0, top)]
+      hierarchy.append((0, true, top))
+
+      while let (index, task) = stack.popLast() {
+        if index < task.childTasks.count {
+          stack.append((index + 1, task))
+          let childPtr = task.childTasks[index]
+          let childTask = tasks[childPtr]!
+          hierarchy.append((stack.count, index == task.childTasks.count - 1, childTask))
+          stack.append((0, childTask))
+        }
+      }
+    }
+    return hierarchy
+  }
+
+  func remove(from: String, upTo: String) -> String {
+    from.withCString {
+      if let found = strstr($0, upTo) {
+        return String(cString: found + strlen(upTo))
+      }
+      return from
+    }
+  }
+
+  func symbolicateBacktracePointer(ptr: swift_reflection_ptr_t) -> String {
+    guard let name = inspector.getSymbol(address: ptr).name else {
+      return "<\(hex: ptr)>"
+    }
+
+    return remove(from: name, upTo: " resume partial function for ")
+  }
+
+  func flagsStrings<T: BinaryInteger>(flags: T, strings: [T: String]) -> [String] {
+    return strings.sorted{ $0.key < $1.key }
+                  .filter({ ($0.key & flags) != 0})
+                  .map{ $0.value }
+  }
+
+  func flagsString<T: BinaryInteger>(flags: T, strings: [T: String]) -> String {
+    let flagStrs = flagsStrings(flags: flags, strings: strings)
+    if flagStrs.isEmpty {
+      return "0"
+    }
+
+    let flagsStr = flagStrs.joined(separator: "|")
+    return flagsStr
+  }
+
+  func decodeTaskFlags(_ info: TaskInfo) -> (
+    priority: UInt32,
+    flags: String
+  ) {
+    let priority = (info.jobFlags >> 8) & 0xff
+    let jobFlags = flagsStrings(flags: info.jobFlags, strings: [
+      1 << 24: "childTask",
+      1 << 25: "future",
+      1 << 26: "groupChildTask",
+      1 << 28: "asyncLetTask"
+    ])
+    let taskFlags = flagsStrings(flags: info.taskStatusFlags, strings: [
+      0x100: "cancelled",
+      0x200: "locked",
+      0x400: "escalated",
+      0x800: "running"
+    ])
+    let allFlags = jobFlags + taskFlags
+    let flagsStr = allFlags.isEmpty ? "0" : allFlags.joined(separator: "|")
+    return (priority, flagsStr)
+  }
+
+  func decodeActorFlags(_ flags: UInt64) -> (
+    status: String,
+    flags: String,
+    maxPriority: UInt64
+  ) {
+    let statuses: [UInt64: String] = [
+      0: "idle",
+      1: "scheduled",
+      2: "running",
+      3: "zombie-latching",
+      4: "zombie-ready-for-deallocation"
+    ]
+    let flagsString = flagsString(flags: flags, strings: [
+      1 << 3: "hasActiveInlineJob",
+      1 << 4: "isDistributedRemote"
+    ])
+
+    let status = flags & 0x7
+    let maxPriority = (flags >> 8) & 0xff
+    return (
+      status: statuses[status] ?? "unknown(\(status))",
+      flags: flagsString,
+      maxPriority: maxPriority
+    )
+  }
+
+  func dumpTasks() {
+    print("TASKS")
+
+    var lastChilds: [Bool] = []
+
+    let hierarchy = taskHierarchy()
+    for (i, (level, lastChild, task)) in hierarchy.enumerated() {
+      lastChilds.removeSubrange(level...)
+      lastChilds.append(lastChild)
+
+      let nextEntry = i < hierarchy.count - 1 ? hierarchy[i + 1] : nil
+      let prevEntry = i > 0 ? hierarchy[i - 1] : nil
+
+      let levelWillDecrease = level > (nextEntry?.level ?? -1)
+      let levelDidIncrease = level > (prevEntry?.level ?? -1)
+
+      var prefix = ""
+      for lastChild in lastChilds {
+        prefix += lastChild ? "     " : "   | "
+      }
+      prefix += "   "
+      let firstPrefix = String(prefix.dropLast(5) + (
+          level == 0 ? "   " :
+          lastChild  ? "`--" :
+                       "+--"))
+      if levelDidIncrease {
+        print(prefix)
+      }
+
+      var firstLine = true
+      func output(_ str: String) {
+        print((firstLine ? firstPrefix : prefix) + str)
+        firstLine = false
+      }
+
+      let runJobSymbol = inspector.getSymbol(address: task.runJob)
+      let runJobLibrary = runJobSymbol.library ?? "<unknown>"
+
+      let symbolicatedBacktrace = task.asyncBacktrace.map(symbolicateBacktracePointer)
+
+      let flags = decodeTaskFlags(task)
+
+      output("Task \(hex: task.id) - flags=\(flags.flags) priority=\(hex: flags.priority) address=\(hex: task.address)")
+      if let parent = task.parent {
+        output("parent: \(hex: parent)")
+      }
+
+      if let first = symbolicatedBacktrace.first {
+        output("async backtrace: \(first)")
+        for entry in symbolicatedBacktrace.dropFirst() {
+          output("                 \(entry)")
+        }
+      }
+
+      output("resume function: \(symbolicateBacktracePointer(ptr: task.runJob)) in \(runJobLibrary)")
+      output("task allocator: \(task.allocatorTotalSize) bytes in \(task.allocatorTotalChunks) chunks")
+
+      if task.childTasks.count > 0 {
+        let s = task.childTasks.count > 1 ? "s" : ""
+        output("* \(task.childTasks.count) child task\(s)")
+      }
+
+      if (task.childTasks.isEmpty) && i < hierarchy.count - 1 {
+        print(prefix)
+      }
+    }
+
+    print("")
+  }
+
+  func dumpActors() {
+    print("ACTORS")
+
+    for actor in actors {
+      let metadata = swift_reflection_metadataForObject(context, UInt(actor))
+      let metadataName = name(metadata: swift_reflection_ptr_t(metadata)) ?? "<unknown class name>"
+      let info = swift_reflection_actorInfo(context, actor);
+
+      let flags = decodeActorFlags(info.Flags)
+
+      print("  \(hex: actor) \(metadataName) status=\(flags.status) flags=\(flags.flags) maxPriority=\(hex: flags.maxPriority)")
+
+      func jobStr(_ job: swift_reflection_ptr_t) -> String {
+        if let task = tasks[job] {
+          return "Task \(hex: task.id) \(symbolicateBacktracePointer(ptr: task.runJob))"
+        }
+        return "<internal job \(hex: job)>"
+      }
+
+      var job = info.FirstJob
+      if job == 0 {
+        print("    no jobs queued")
+      } else {
+        print("    job queue: \(jobStr(job))")
+        while job != 0 {
+          job = swift_reflection_nextJob(context, job);
+          if job != 0 {
+            print("               \(jobStr(job))")
+          }
+        }
+      }
+        print("")
+    }
+  }
+
+  func dumpThreads() {
+    print("THREADS")
+    if threadCurrentTasks.isEmpty {
+      print("  no threads with active tasks")
+      return
+    }
+
+    for (thread, task) in threadCurrentTasks {
+      let taskStr: String
+      if let info = tasks[task] {
+        taskStr = "\(hex: info.id)"
+      } else {
+        taskStr = "<unknown task \(hex: task)>"
+      }
+      print("  Thread \(hex: thread) - current task: \(taskStr)")
+    }
+  }
+}

tools/swift-inspect/Sources/swift-inspect/Inspector.swift

@@ -18,6 +18,7 @@ class Inspector {
   let task: task_t
   let symbolicator: CSTypeRef
   let swiftCore: CSTypeRef
+  let swiftConcurrency: CSTypeRef
   
   init?(pid: pid_t) {
     task = Self.findTask(pid, tryForkCorpse: false)
@@ -26,6 +27,8 @@ class Inspector {
     symbolicator = CSSymbolicatorCreateWithTask(task)
     swiftCore = CSSymbolicatorGetSymbolOwnerWithNameAtTime(
       symbolicator, "libswiftCore.dylib", kCSNow)
+    swiftConcurrency = CSSymbolicatorGetSymbolOwnerWithNameAtTime(
+      symbolicator, "libswift_Concurrency.dylib", kCSNow)
     _ = task_start_peeking(task)
   }
   
@@ -74,8 +77,11 @@ class Inspector {
   }
   
   func getAddr(symbolName: String) -> swift_addr_t {
-    let symbol = CSSymbolOwnerGetSymbolWithMangledName(swiftCore,
+    let fullName = "_" + symbolName
-                                                       "_" + symbolName)
+    var symbol = CSSymbolOwnerGetSymbolWithMangledName(swiftCore, fullName)
+    if CSIsNull(symbol) {
+      symbol = CSSymbolOwnerGetSymbolWithMangledName(swiftConcurrency, fullName)
+    }
     let range = CSSymbolGetRange(symbol)
     return swift_addr_t(range.location)
   }
@@ -106,6 +112,57 @@ class Inspector {
     return task_peek(task, address, mach_vm_size_t(size))
   }
 
+  func threadCurrentTasks() -> [(threadID: UInt64, currentTask: swift_addr_t)] {
+    var threadList: UnsafeMutablePointer<thread_t>? = nil
+    var threadCount: mach_msg_type_number_t = 0
+
+    var kr = task_threads(task, &threadList, &threadCount)
+    if kr != KERN_SUCCESS {
+      print("Unable to gather threads of remote process: \(machErrStr(kr))")
+      return []
+    }
+
+    defer {
+      // Deallocate the port rights for the threads.
+      for i in 0..<threadCount {
+        mach_port_deallocate(mach_task_self_, threadList![Int(i)]);
+      }
+
+      // Deallocate the thread list.
+      let ptr = vm_address_t(bitPattern: threadList)
+      let size = vm_size_t(MemoryLayout<thread_t>.size) * vm_size_t(threadCount)
+      vm_deallocate(mach_task_self_, ptr, size);
+    }
+
+    var results: [(threadID: UInt64, currentTask: swift_addr_t)] = []
+    for i in 0..<threadCount {
+      let THREAD_IDENTIFIER_INFO_COUNT = MemoryLayout<thread_identifier_info_data_t>.size / MemoryLayout<natural_t>.size
+      var info = thread_identifier_info_data_t()
+      var infoCount = mach_msg_type_number_t(THREAD_IDENTIFIER_INFO_COUNT)
+      withUnsafeMutablePointer(to: &info) {
+        $0.withMemoryRebound(to: integer_t.self, capacity: THREAD_IDENTIFIER_INFO_COUNT) {
+          kr = thread_info(threadList![Int(i)],
+                           thread_flavor_t(THREAD_IDENTIFIER_INFO), $0,
+                           &infoCount)
+        }
+      }
+      if (kr != KERN_SUCCESS) {
+        print("Unable to get info for thread \(i): \(machErrStr(kr))")
+      } else {
+        let tlsStart = info.thread_handle
+        if tlsStart != 0 {
+          let SWIFT_CONCURRENCY_TASK_KEY = 103
+          let currentTaskPointer = tlsStart + UInt64(SWIFT_CONCURRENCY_TASK_KEY * MemoryLayout<UnsafeRawPointer>.size)
+          if let ptr = read(address: currentTaskPointer, size: MemoryLayout<UnsafeRawPointer>.size) {
+            let currentTask = ptr.load(as: UInt.self)
+            results.append((threadID: info.thread_id, currentTask: swift_addr_t(currentTask)))
+          }
+        }
+      }
+    }
+    return results
+  }
+
   enum Callbacks {
     static let QueryDataLayout: @convention(c)
       (UnsafeMutableRawPointer?,

tools/swift-inspect/Sources/swift-inspect/InterpolationExtensions.swift

@@ -13,7 +13,7 @@
 import SwiftRemoteMirror
 
 extension DefaultStringInterpolation {
-  mutating func appendInterpolation(hex: swift_reflection_ptr_t) {
+  mutating func appendInterpolation<T>(hex: T) where T: BinaryInteger {
     appendInterpolation("0x")
     appendInterpolation(String(hex, radix: 16))
   }

tools/swift-inspect/Sources/swift-inspect/main.swift

@@ -169,6 +169,7 @@ struct SwiftInspect: ParsableCommand {
       DumpGenericMetadata.self,
       DumpCacheNodes.self,
       DumpArrays.self,
+      DumpConcurrency.self,
     ])
 }
 
@@ -260,7 +261,7 @@ struct DumpCacheNodes: ParsableCommand {
 
 struct DumpArrays: ParsableCommand {
   static let configuration = CommandConfiguration(
-    abstract: "Print the target's metadata cache nodes.")
+    abstract: "Print information about array objects in the target.")
 
   @OptionGroup()
   var options: UniversalOptions
@@ -272,4 +273,18 @@ struct DumpArrays: ParsableCommand {
   }
 }
 
+struct DumpConcurrency: ParsableCommand {
+  static let configuration = CommandConfiguration(
+    abstract: "Print information about the target's concurrency runtime.")
+
+  @OptionGroup()
+  var options: UniversalOptions
+
+  func run() throws {
+    try withReflectionContext(nameOrPid: options.nameOrPid) {
+      try dumpConcurrency(context: $0, inspector: $1)
+    }
+  }
+}
+
 SwiftInspect.main()

tools/swift-inspect/Sources/swift-inspect/symbolication.swift

@@ -58,6 +58,13 @@ enum Sym {
   static let CSSymbolicatorGetSymbolWithAddressAtTime: @convention(c)
     (CSSymbolicatorRef, mach_vm_address_t, CSMachineTime) -> CSSymbolRef =
     symbol(coreSymbolicationHandle, "CSSymbolicatorGetSymbolWithAddressAtTime")
+  static let CSSymbolicatorForeachSymbolOwnerAtTime:
+    @convention(c) (CSSymbolicatorRef, CSMachineTime, @convention(block) (CSSymbolOwnerRef) -> Void) -> UInt =
+      symbol(coreSymbolicationHandle, "CSSymbolicatorForeachSymbolOwnerAtTime")
+  static let CSSymbolOwnerGetBaseAddress: @convention(c) (CSSymbolOwnerRef) -> mach_vm_address_t =
+    symbol(symbolicationHandle, "CSSymbolOwnerGetBaseAddress")
+  static let CSIsNull: @convention(c) (CSTypeRef) -> CBool =
+    symbol(coreSymbolicationHandle, "CSIsNull")
   static let task_start_peeking: @convention(c) (task_t) -> kern_return_t =
     symbol(symbolicationHandle, "task_start_peeking")
   static let task_peek: @convention(c) (task_t, mach_vm_address_t, mach_vm_size_t,
@@ -77,13 +84,6 @@ enum Sym {
     @convention(c) (task_t, UnsafeMutableRawPointer?, CUnsignedInt, vm_range_recorder_t)
       -> Void =
     symbol(symbolicationHandle, "task_enumerate_malloc_blocks")
-
-  static let CSSymbolicatorForeachSymbolOwnerAtTime:
-    @convention(c) (CSSymbolicatorRef, CSMachineTime, @convention(block) (CSSymbolOwnerRef) -> Void) -> UInt =
-      symbol(coreSymbolicationHandle, "CSSymbolicatorForeachSymbolOwnerAtTime")
-
-  static let CSSymbolOwnerGetBaseAddress: @convention(c) (CSSymbolOwnerRef) -> mach_vm_address_t =
-    symbol(symbolicationHandle, "CSSymbolOwnerGetBaseAddress")
 }
 
 typealias CSMachineTime = UInt64
@@ -173,6 +173,10 @@ func CSSymbolOwnerGetBaseAddress(_ symbolOwner: CSSymbolOwnerRef) -> mach_vm_add
     return Sym.CSSymbolOwnerGetBaseAddress(symbolOwner)
 }
 
+func CSIsNull(_ symbol: CSTypeRef) -> Bool {
+  Sym.CSIsNull(symbol)
+}
+
 func task_start_peeking(_ task: task_t) -> Bool {
   let result = Sym.task_start_peeking(task)
   if result == KERN_SUCCESS {
@@ -189,7 +193,6 @@ func task_peek(
   var ptr: UnsafeRawPointer? = nil
   let result = Sym.task_peek(task, start, size, &ptr)
   if result != KERN_SUCCESS {
-    print("Unable to read (\(start), \(size)): \(machErrStr(result))", to: &Std.err)
     return nil
   }
   return ptr