private static void ChainStateMachinesBasedOnJointableTasks(DebuggerContext context, List <AsyncStateMachine> allStateMachines)
{
foreach (AsyncStateMachine?stateMachine in allStateMachines)
{
if (stateMachine.Previous is null)
{
try
{
ClrObject joinableTask = stateMachine.StateMachine.TryGetObjectField("<>4__this");
ClrObject wrappedTask = joinableTask.TryGetObjectField("wrappedTask");
if (!wrappedTask.IsNull)
{
AsyncStateMachine?previousStateMachine = allStateMachines
.FirstOrDefault(s => s.Task.Address == wrappedTask.Address);
if (previousStateMachine is object && stateMachine != previousStateMachine)
{
stateMachine.Previous = previousStateMachine;
previousStateMachine.Next = stateMachine;
previousStateMachine.DependentCount++;
}
}
}
#pragma warning disable CA1031 // Do not catch general exception types
catch (Exception ex)
#pragma warning restore CA1031 // Do not catch general exception types
{
context.Output.WriteLine($"Fail to fix continuation of state {stateMachine.StateMachine.Address:x} Error: {ex.Message}");
}
}
}
}
private static void ChainStateMachinesBasedOnTaskContinuations(DebuggerContext context, Dictionary <ulong, AsyncStateMachine> knownStateMachines)
{
foreach (AsyncStateMachine?stateMachine in knownStateMachines.Values)
{
ClrObject taskObject = stateMachine.Task;
try
{
while (!taskObject.IsNull)
{
// 3 cases in order to get the _target:
// 1. m_continuationObject.m_action._target
// 2. m_continuationObject._target
// 3. m_continuationObject.m_task.m_stateObject._target
ClrObject continuationObject = taskObject.TryGetObjectField("m_continuationObject");
if (continuationObject.IsNull)
{
break;
}
ChainStateMachineBasedOnTaskContinuations(knownStateMachines, stateMachine, continuationObject);
taskObject = continuationObject;
}
}
#pragma warning disable CA1031 // Do not catch general exception types
catch (Exception ex)
#pragma warning restore CA1031 // Do not catch general exception types
{
context.Output.WriteLine($"Fail to fix continuation of state {stateMachine.StateMachine.Address:x} Error: {ex.Message}");
}
}
}
private static void MarkThreadingBlockTasks(DebuggerContext context, List <AsyncStateMachine> allStateMachines)
{
foreach (var thread in context.Runtime.Threads)
{
var stackFrame = thread.EnumerateStackTrace().Take(50).FirstOrDefault(
f => f.Method is { } method &&
string.Equals(f.Method.Name, "CompleteOnCurrentThread", StringComparison.Ordinal) &&
string.Equals(f.Method.Type?.Name, "Microsoft.VisualStudio.Threading.JoinableTask", StringComparison.Ordinal));
if (stackFrame is object)
{
var visitedObjects = new HashSet <ulong>();
foreach (IClrStackRoot stackRoot in thread.EnumerateStackRoots())
{
ClrObject stackObject = stackRoot.Object;
if (string.Equals(stackObject.Type?.Name, "Microsoft.VisualStudio.Threading.JoinableTask", StringComparison.Ordinal) ||
string.Equals(stackObject.Type?.BaseType?.Name, "Microsoft.VisualStudio.Threading.JoinableTask", StringComparison.Ordinal))
{
if (visitedObjects.Add(stackObject.Address))
{
var joinableTaskObject = new ClrObject(stackObject.Address, stackObject.Type);
int state = joinableTaskObject.ReadField <int>("state");
if ((state & 0x10) == 0x10)
{
// This flag indicates the JTF is blocking the thread
var wrappedTask = joinableTaskObject.TryGetObjectField("wrappedTask");
if (!wrappedTask.IsNull)
{
var blockingStateMachine = allStateMachines
.FirstOrDefault(s => s.Task.Address == wrappedTask.Address);
if (blockingStateMachine is object)
{
blockingStateMachine.BlockedThread = thread.OSThreadId;
blockingStateMachine.BlockedJoinableTask = joinableTaskObject;
}
}
break;
}
}
}
}
}
}
}
private static void ChainStateMachineBasedOnTaskContinuations(Dictionary <ulong, AsyncStateMachine> knownStateMachines, AsyncStateMachine stateMachine, ClrObject continuationObject)
{
var continuationAction = continuationObject.TryGetObjectField("m_action");
// case 1
var continuationTarget = continuationAction.TryGetObjectField("_target");
if (continuationTarget.IsNull)
{
// case 2
continuationTarget = continuationObject.TryGetObjectField("_target");
if (continuationTarget.IsNull)
{
// case 3
continuationTarget = continuationObject.TryGetObjectField("m_task").TryGetObjectField("m_stateObject").TryGetObjectField("_target");
}
}
while (!continuationTarget.IsNull)
{
// now get the continuation from the target
var continuationTargetStateMachine = continuationTarget.TryGetObjectField("m_stateMachine");
if (!continuationTargetStateMachine.IsNull)
{
AsyncStateMachine targetAsyncState;
if (knownStateMachines.TryGetValue(continuationTargetStateMachine.Address, out targetAsyncState) && targetAsyncState != stateMachine)
{
stateMachine.Next = targetAsyncState;
stateMachine.DependentCount++;
targetAsyncState.Previous = stateMachine;
}
break;
}
else
{
var nextContinuation = continuationTarget.TryGetObjectField("m_continuation");
continuationTarget = nextContinuation.TryGetObjectField("_target");
}
}
var items = continuationObject.TryGetObjectField("_items");
if (!items.IsNull && items.IsArray && items.ContainsPointers)
{
foreach (var promise in items.EnumerateReferences(true))
{
if (!promise.IsNull)
{
var innerContinuationObject = promise.TryGetObjectField("m_continuationObject");
if (!innerContinuationObject.IsNull)
{
ChainStateMachineBasedOnTaskContinuations(knownStateMachines, stateMachine, innerContinuationObject);
}
else
{
ChainStateMachineBasedOnTaskContinuations(knownStateMachines, stateMachine, promise);
}
}
}
}
}
