dotnet · stephentoub · May 30, 2018 · May 29, 2018
diff --git a/src/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncMethodBuilder.cs b/src/System.Private.CoreLib/src/System/Runtime/CompilerServices/AsyncMethodBuilder.cs
@@ -498,7 +498,7 @@ private IAsyncStateMachineBox GetStateMachineBox<TStateMachine>(
         /// event about the state machine if it's being finalized without having been completed.
         /// </summary>
         /// <typeparam name="TStateMachine">Specifies the type of the state machine.</typeparam>
-        private sealed class DebugFinalizableAsyncStateMachineBox<TStateMachine> :
+        private sealed class DebugFinalizableAsyncStateMachineBox<TStateMachine> : // SOS DumpAsync command depends on this name
             AsyncStateMachineBox<TStateMachine>
             where TStateMachine : IAsyncStateMachine
         {
@@ -517,7 +517,7 @@ private sealed class DebugFinalizableAsyncStateMachineBox<TStateMachine> :
         /// <summary>A strongly-typed box for Task-based async state machines.</summary>
         /// <typeparam name="TStateMachine">Specifies the type of the state machine.</typeparam>
         /// <typeparam name="TResult">Specifies the type of the Task's result.</typeparam>
-        private class AsyncStateMachineBox<TStateMachine> :
+        private class AsyncStateMachineBox<TStateMachine> : // SOS DumpAsync command depends on this name
             Task<TResult>, IAsyncStateMachineBox
             where TStateMachine : IAsyncStateMachine
         {
@@ -527,7 +527,7 @@ private class AsyncStateMachineBox<TStateMachine> :
             /// <summary>A delegate to the <see cref="MoveNext"/> method.</summary>
             private Action _moveNextAction;
             /// <summary>The state machine itself.</summary>
-            public TStateMachine StateMachine; // mutable struct; do not make this readonly
+            public TStateMachine StateMachine; // mutable struct; do not make this readonly. SOS DumpAsync command depends on this name.
             /// <summary>Captured ExecutionContext with which to invoke <see cref="MoveNextAction"/>; may be null.</summary>
             public ExecutionContext Context;
 

diff --git a/src/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs b/src/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs
@@ -193,7 +193,7 @@ public class Task : IThreadPoolWorkItem, IAsyncResult, IDisposable
 
         // Can be null, a single continuation, a list of continuations, or s_taskCompletionSentinel,
         // in that order. The logic arround this object assumes it will never regress to a previous state.
-        private volatile object m_continuationObject = null;
+        private volatile object m_continuationObject = null; // SOS DumpAsync command depends on this name
 
         // m_continuationObject is set to this when the task completes.
         private static readonly object s_taskCompletionSentinel = new object();

diff --git a/src/ToolBox/SOS/Strike/apollososdocs.txt b/src/ToolBox/SOS/Strike/apollososdocs.txt
@@ -25,16 +25,16 @@ Object Inspection                  Examining code and stacks
 -----------------------------      -----------------------------
 DumpObj (do)                       Threads
 DumpArray (da)                     ThreadState
-DumpStackObjects (dso)             IP2MD
-DumpHeap                           U
-DumpVC                             DumpStack
-GCRoot                             EEStack
-ObjSize                            CLRStack
-FinalizeQueue                      GCInfo
-PrintException (pe)                EHInfo
-TraverseHeap                       BPMD 
-Watch                              COMState
-                                   StopOnCatch
+DumpAsync                          IP2MD
+DumpStackObjects (dso)             U
+DumpHeap                           DumpStack
+DumpVC                             EEStack
+GCRoot                             CLRStack
+ObjSize                            GCInfo
+FinalizeQueue                      EHInfo
+PrintException (pe)                BPMD
+TraverseHeap                       COMState 
+Watch                              StopOnCatch
                                    SuppressJitOptimization
 
 Examining CLR data structures      Diagnostic Utilities
@@ -340,6 +340,62 @@ The arguments in detail:
 	    5b9a628c  4000002        4         System.Int32   instance        8 y
 	    5b9a628c  4000003        8         System.Int32   instance       12 z
 
+\\
+
+COMMAND: dumpasync.
+!DumpAsync [-mt <MethodTable address>] 
+           [-type <partial type name>]]
+
+!DumpAsync traverses the garbage collected heap, looking for objects representing
+async state machines as created when an async method's state is transferred to the
+heap.  This command recognizes async state machines defined as "async void", "async Task",
+"async Task<T>", "async ValueTask", and "async ValueTask<T>".
+
+The output includes a block of details for each async state machine object found.
+These details include:
+    - a line for the type of the async state machine object, including its MethodTable address,
+      its object address, its size, and its type name.
+    - a line for the state machine type name as contained in the object.
+    - a listing of each field on the state machine.
+    - a line for a continuation from this state machine object, if one or more has been registered.
+    - discovered GC roots for this async state machine object.
+
+For example:
+
+    0:011> !DumpAsync
+    #0
+    000001989f413de0 00007ff88c506ba8      112  System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodD>d__4, test]]
+    StateMachine: Program+<MethodD>d__4 (struct)
+                  MT    Field   Offset                 Type VT     Attr            Value Name
+    00007ff8d3df4b80  400000d        0         System.Int32  1 instance                0 <>1__state
+    00007ff8d3e082c0  400000e        8 ...TaskMethodBuilder  1 instance 000001989f413e38 <>t__builder
+    00007ff8d3dfea90  400000f       10 ...vices.TaskAwaiter  1 instance 000001989f413e40 <>u__1
+    Continuation: 000001989f413e50 (System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodC>d__3, test]])
+    GC roots:
+        Thread 2936c:
+            000000071a37e050 00007ff8d3ac1657 System.Threading.Tasks.Task.SpinThenBlockingWait(Int32, System.Threading.CancellationToken) [d:\repos\coreclr\src\System.Private.CoreLib\src\System\Threading\Tasks\Task.cs @ 2977]
+                rbp+10: 000000071a37e0c0
+                    ->  000001989f413fa0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<Main>d__0, test]]
+                    ->  000001989f413f30 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodA>d__1, test]]
+                    ->  000001989f413ec0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodB>d__2, test]]
+                    ->  000001989f413e50 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodC>d__3, test]]
+                    ->  000001989f413de0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodD>d__4, test]]
+        HandleTable:
+            000001989d8415f8 (pinned handle)
+            -> 00000198af3e1038 System.Object[]
+            -> 000001989f413410 System.Threading.TimerQueue[]
+            -> 000001989f413468 System.Threading.TimerQueue
+            -> 000001989f413330 System.Threading.TimerQueueTimer
+            -> 000001989f412e40 System.Threading.Tasks.Task+DelayPromise
+            -> 000001989f413de0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodD>d__4, test]]
+    ...
+
+
+The arguments in detail:
+
+-mt       List only those state machine objects with the MethodTable given.
+-type     List only those state machine objects whose type name is a
+          substring match of the string provided.
 
 \\
 

diff --git a/src/ToolBox/SOS/Strike/sos.def b/src/ToolBox/SOS/Strike/sos.def
@@ -15,6 +15,8 @@ EXPORTS
     dumparray=DumpArray
     DumpAssembly
     dumpassembly=DumpAssembly
+    DumpAsync
+    dumpasync=DumpAsync
     DumpClass
     dumpclass=DumpClass
     DumpDomain

diff --git a/src/ToolBox/SOS/Strike/sos_unixexports.src b/src/ToolBox/SOS/Strike/sos_unixexports.src
@@ -7,6 +7,7 @@ ClrStack
 CreateDump
 DumpArray
 DumpAssembly
+DumpAsync
 DumpClass
 DumpDomain
 DumpGCData

diff --git a/src/ToolBox/SOS/Strike/sosdocs.txt b/src/ToolBox/SOS/Strike/sosdocs.txt
@@ -25,15 +25,15 @@ Object Inspection                  Examining code and stacks
 -----------------------------      -----------------------------
 DumpObj (do)                       Threads
 DumpArray (da)                     ThreadState
-DumpStackObjects (dso)             IP2MD
-DumpHeap                           U
-DumpVC                             DumpStack
-GCRoot                             EEStack
-ObjSize                            CLRStack
-FinalizeQueue                      GCInfo
-PrintException (pe)                EHInfo
-TraverseHeap                       BPMD 
-                                   COMState
+DumpAsync                          IP2MD
+DumpStackObjects (dso)             U
+DumpHeap                           DumpStack
+DumpVC                             EEStack
+GCRoot                             CLRStack
+ObjSize                            GCInfo
+FinalizeQueue                      EHInfo
+PrintException (pe)                BPMD
+TraverseHeap                       COMState
 
 Examining CLR data structures      Diagnostic Utilities
 -----------------------------      -----------------------------
@@ -338,6 +338,62 @@ The arguments in detail:
 	    5b9a628c  4000002        4         System.Int32   instance        8 y
 	    5b9a628c  4000003        8         System.Int32   instance       12 z
 
+\\
+
+COMMAND: dumpasync.
+!DumpAsync [-mt <MethodTable address>] 
+           [-type <partial type name>]]
+
+!DumpAsync traverses the garbage collected heap, looking for objects representing
+async state machines as created when an async method's state is transferred to the
+heap.  This command recognizes async state machines defined as "async void", "async Task",
+"async Task<T>", "async ValueTask", and "async ValueTask<T>".
+
+The output includes a block of details for each async state machine object found.
+These details include:
+    - a line for the type of the async state machine object, including its MethodTable address,
+      its object address, its size, and its type name.
+    - a line for the state machine type name as contained in the object.
+    - a listing of each field on the state machine.
+    - a line for a continuation from this state machine object, if one or more has been registered.
+    - discovered GC roots for this async state machine object.
+
+For example:
+
+    0:011> !DumpAsync
+    #0
+    000001989f413de0 00007ff88c506ba8      112  System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodD>d__4, test]]
+    StateMachine: Program+<MethodD>d__4 (struct)
+                  MT    Field   Offset                 Type VT     Attr            Value Name
+    00007ff8d3df4b80  400000d        0         System.Int32  1 instance                0 <>1__state
+    00007ff8d3e082c0  400000e        8 ...TaskMethodBuilder  1 instance 000001989f413e38 <>t__builder
+    00007ff8d3dfea90  400000f       10 ...vices.TaskAwaiter  1 instance 000001989f413e40 <>u__1
+    Continuation: 000001989f413e50 (System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodC>d__3, test]])
+    GC roots:
+        Thread 2936c:
+            000000071a37e050 00007ff8d3ac1657 System.Threading.Tasks.Task.SpinThenBlockingWait(Int32, System.Threading.CancellationToken) [d:\repos\coreclr\src\System.Private.CoreLib\src\System\Threading\Tasks\Task.cs @ 2977]
+                rbp+10: 000000071a37e0c0
+                    ->  000001989f413fa0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<Main>d__0, test]]
+                    ->  000001989f413f30 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodA>d__1, test]]
+                    ->  000001989f413ec0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodB>d__2, test]]
+                    ->  000001989f413e50 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodC>d__3, test]]
+                    ->  000001989f413de0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodD>d__4, test]]
+        HandleTable:
+            000001989d8415f8 (pinned handle)
+            -> 00000198af3e1038 System.Object[]
+            -> 000001989f413410 System.Threading.TimerQueue[]
+            -> 000001989f413468 System.Threading.TimerQueue
+            -> 000001989f413330 System.Threading.TimerQueueTimer
+            -> 000001989f412e40 System.Threading.Tasks.Task+DelayPromise
+            -> 000001989f413de0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodD>d__4, test]]
+    ...
+
+
+The arguments in detail:
+
+-mt       List only those state machine objects with the MethodTable given.
+-type     List only those state machine objects whose type name is a
+          substring match of the string provided.
 
 \\
 

diff --git a/src/ToolBox/SOS/Strike/sosdocsunix.txt b/src/ToolBox/SOS/Strike/sosdocsunix.txt
@@ -25,12 +25,12 @@ Object Inspection                  Examining code and stacks
 -----------------------------      -----------------------------
 DumpObj (dumpobj)                  Threads (clrthreads)
 DumpArray                          ThreadState
-DumpStackObjects (dso)             IP2MD (ip2md)
-DumpHeap (dumpheap)                u (clru)
-DumpVC                             DumpStack (dumpstack)
-GCRoot (gcroot)                    EEStack (eestack)
-PrintException (pe)                ClrStack (clrstack) 
-                                   GCInfo
+DumpAsync (dumpasync)              IP2MD (ip2md)
+DumpStackObjects (dso)             u (clru)
+DumpHeap (dumpheap)                DumpStack (dumpstack)
+DumpVC                             EEStack (eestack)
+GCRoot (gcroot)                    CLRStack (clrstack)
+PrintException (pe)                GCInfo
                                    EHInfo
                                    bpmd (bpmd)
 
@@ -199,6 +199,62 @@ The arguments in detail:
 	    5b9a628c  4000002        4         System.Int32   instance        8 y
 	    5b9a628c  4000003        8         System.Int32   instance       12 z
 
+\\
+
+COMMAND: dumpasync.
+!DumpAsync [-mt <MethodTable address>] 
+           [-type <partial type name>]]
+
+!DumpAsync traverses the garbage collected heap, looking for objects representing
+async state machines as created when an async method's state is transferred to the
+heap.  This command recognizes async state machines defined as "async void", "async Task",
+"async Task<T>", "async ValueTask", and "async ValueTask<T>".
+
+The output includes a block of details for each async state machine object found.
+These details include:
+    - a line for the type of the async state machine object, including its MethodTable address,
+      its object address, its size, and its type name.
+    - a line for the state machine type name as contained in the object.
+    - a listing of each field on the state machine.
+    - a line for a continuation from this state machine object, if one or more has been registered.
+    - discovered GC roots for this async state machine object.
+
+For example:
+
+    (lldb) dumpasync
+    #0
+    000001989f413de0 00007ff88c506ba8      112  System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodD>d__4, test]]
+    StateMachine: Program+<MethodD>d__4 (struct)
+                  MT    Field   Offset                 Type VT     Attr            Value Name
+    00007ff8d3df4b80  400000d        0         System.Int32  1 instance                0 <>1__state
+    00007ff8d3e082c0  400000e        8 ...TaskMethodBuilder  1 instance 000001989f413e38 <>t__builder
+    00007ff8d3dfea90  400000f       10 ...vices.TaskAwaiter  1 instance 000001989f413e40 <>u__1
+    Continuation: 000001989f413e50 (System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodC>d__3, test]])
+    GC roots:
+        Thread 2936c:
+            000000071a37e050 00007ff8d3ac1657 System.Threading.Tasks.Task.SpinThenBlockingWait(Int32, System.Threading.CancellationToken) [d:\repos\coreclr\src\System.Private.CoreLib\src\System\Threading\Tasks\Task.cs @ 2977]
+                rbp+10: 000000071a37e0c0
+                    ->  000001989f413fa0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<Main>d__0, test]]
+                    ->  000001989f413f30 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodA>d__1, test]]
+                    ->  000001989f413ec0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodB>d__2, test]]
+                    ->  000001989f413e50 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodC>d__3, test]]
+                    ->  000001989f413de0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodD>d__4, test]]
+        HandleTable:
+            000001989d8415f8 (pinned handle)
+            -> 00000198af3e1038 System.Object[]
+            -> 000001989f413410 System.Threading.TimerQueue[]
+            -> 000001989f413468 System.Threading.TimerQueue
+            -> 000001989f413330 System.Threading.TimerQueueTimer
+            -> 000001989f412e40 System.Threading.Tasks.Task+DelayPromise
+            -> 000001989f413de0 System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[[System.Threading.Tasks.VoidTaskResult, System.Private.CoreLib],[Program+<MethodD>d__4, test]]
+    ...
+
+
+The arguments in detail:
+
+-mt       List only those state machine objects with the MethodTable given.
+-type     List only those state machine objects whose type name is a
+          substring match of the string provided.
 
 \\