文章目錄
需要在 return 前自行 new ValueTask 嗎？
上個月黑大的 閱讀筆記 - 使用 .NET Async/Await 的常見錯誤 跟同事討論起 ValueTask 的用法，大意是 ValueTask 在使用上只需要將方法簽章改為 ValueTask<T> 就好嗎？ 還是應該在回傳時 new ValueTask<T>()
網路上的文章兩種寫法都有，但較有公信心的內容看似都有 new 的動作，雖然有用過 ValueTask 但我就是勉強稱得上用過的程度，經不起強大同事針針見血地的問題，為了避免錯誤的意見，我重新檢視了相關文章跟資料，覺得好像應該要 new 才對？？ 不過想要搞清楚的想法還是在我心裡悄悄地發芽了，只是左思右想還是沒有非常確定答案，乾脆先紀錄一下目前發現，待其他高手提點再來補充囉
基本環境說明
- macOS Mojave 10.14.6
- .NET Core SDK 2.2.301 (.NET Core Runtime 2.2.6)
測試程式碼
static async Task Main() { await TestTask(); await TestValueTask(); await TestValueTaskWithNew(); } private static async Task<int> TestTask() { await Task.Delay(100); return 100; } private static async ValueTask<int> TestValueTask() { await Task.Delay(100); return 10; } private static ValueTask<int> TestValueTaskWithNew() { return new ValueTask<int>(0); }
IL - Intermediate Language
先說個人發現，有興趣的朋友可以再看看詳細 IL 內容
Task<int>與async ValueTask<int>Task<int>使用 TaskAwaiter; 而async ValueTask<int>使用 ValueTaskAwaiterTask<int>回傳 class ;async ValueTask<int>回傳 valuetype
async ValueTask<int>與ValueTask<int>的差異- 僅
async ValueTask<int>實作 IAsyncStateMachine;ValueTask<int>未實作 IAsyncStateMachine - 僅
async ValueTask<int>存在 MoveNext() 方法
- 僅
Task<int>Collapse or Expand
// Type: ValueTaskResearch.Program // Assembly: ValueTaskResearch, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null // MVID: 99E6E072-258E-433E-84E8-C626124D37C8 // Location: /Users/yowko.tsai/ValueTaskResearch/ValueTaskResearch/bin/Debug/netcoreapp2.2/ValueTaskResearch.dll // Sequence point data from /Users/yowko.tsai/ValueTaskResearch/ValueTaskResearch/bin/Debug/netcoreapp2.2/ValueTaskResearch.pdb .class private auto ansi beforefieldinit ValueTaskResearch.Program extends [System.Runtime]System.Object { .class nested private sealed auto ansi beforefieldinit '<Main>d__0' extends [System.Runtime]System.Object implements [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine { .custom instance void [System.Runtime]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = (01 00 00 00 ) .field public int32 '<>1__state' .field public valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder '<>t__builder' .field private valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32> '<>u__1' .method public hidebysig specialname rtspecialname instance void .ctor() cil managed { .maxstack 8 IL_0000: ldarg.0 // this IL_0001: call instance void [System.Runtime]System.Object::.ctor() IL_0006: nop IL_0007: ret } // end of method '<Main>d__0'::.ctor .method private final hidebysig virtual newslot instance void MoveNext() cil managed { .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::MoveNext() .maxstack 3 .locals init ( [0] int32 V_0, [1] valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32> V_1, [2] class ValueTaskResearch.Program/'<Main>d__0' V_2, [3] class [System.Runtime]System.Exception V_3 ) IL_0000: ldarg.0 // this IL_0001: ldfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0006: stloc.0 // V_0 .try { IL_0007: ldloc.0 // V_0 IL_0008: brfalse.s IL_000c IL_000a: br.s IL_000e IL_000c: br.s IL_0047 // [8 9 - 8 10] IL_000e: nop // [9 13 - 9 30] IL_000f: call class [System.Runtime]System.Threading.Tasks.Task`1<int32> ValueTaskResearch.Program::TestTask() IL_0014: callvirt instance valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<!0/*int32*/> class [System.Runtime]System.Threading.Tasks.Task`1<int32>::GetAwaiter() IL_0019: stloc.1 // V_1 IL_001a: ldloca.s V_1 IL_001c: call instance bool valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32>::get_IsCompleted() IL_0021: brtrue.s IL_0063 IL_0023: ldarg.0 // this IL_0024: ldc.i4.0 IL_0025: dup IL_0026: stloc.0 // V_0 IL_0027: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_002c: ldarg.0 // this IL_002d: ldloc.1 // V_1 IL_002e: stfld valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32> ValueTaskResearch.Program/'<Main>d__0'::'<>u__1' IL_0033: ldarg.0 // this IL_0034: stloc.2 // V_2 IL_0035: ldarg.0 // this IL_0036: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_003b: ldloca.s V_1 IL_003d: ldloca.s V_2 IL_003f: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::AwaitUnsafeOnCompleted<valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32>, class ValueTaskResearch.Program/'<Main>d__0'>(!!0/*valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32>*/&, !!1/*class ValueTaskResearch.Program/'<Main>d__0'*/&) IL_0044: nop IL_0045: leave.s IL_0099 IL_0047: ldarg.0 // this IL_0048: ldfld valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32> ValueTaskResearch.Program/'<Main>d__0'::'<>u__1' IL_004d: stloc.1 // V_1 IL_004e: ldarg.0 // this IL_004f: ldflda valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32> ValueTaskResearch.Program/'<Main>d__0'::'<>u__1' IL_0054: initobj valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32> IL_005a: ldarg.0 // this IL_005b: ldc.i4.m1 IL_005c: dup IL_005d: stloc.0 // V_0 IL_005e: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0063: ldloca.s V_1 IL_0065: call instance !0/*int32*/ valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter`1<int32>::GetResult() IL_006a: pop IL_006b: leave.s IL_0085 } // end of .try catch [System.Runtime]System.Exception { IL_006d: stloc.3 // V_3 IL_006e: ldarg.0 // this IL_006f: ldc.i4.s -2 // 0xfe IL_0071: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0076: ldarg.0 // this IL_0077: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_007c: ldloc.3 // V_3 IL_007d: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::SetException(class [System.Runtime]System.Exception) IL_0082: nop IL_0083: leave.s IL_0099 } // end of catch // [13 9 - 13 10] IL_0085: ldarg.0 // this IL_0086: ldc.i4.s -2 // 0xfe IL_0088: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_008d: ldarg.0 // this IL_008e: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_0093: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::SetResult() IL_0098: nop IL_0099: ret } // end of method '<Main>d__0'::MoveNext .method private final hidebysig virtual newslot instance void SetStateMachine( class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine stateMachine ) cil managed { .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerHiddenAttribute::.ctor() = (01 00 00 00 ) .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::SetStateMachine(class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine) .maxstack 8 IL_0000: ret } // end of method '<Main>d__0'::SetStateMachine } // end of class '<Main>d__0' .class nested private sealed auto ansi beforefieldinit '<TestTask>d__1' extends [System.Runtime]System.Object implements [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine { .custom instance void [System.Runtime]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = (01 00 00 00 ) .field public int32 '<>1__state' .field public valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32> '<>t__builder' .field private valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter '<>u__1' .method public hidebysig specialname rtspecialname instance void .ctor() cil managed { .maxstack 8 IL_0000: ldarg.0 // this IL_0001: call instance void [System.Runtime]System.Object::.ctor() IL_0006: nop IL_0007: ret } // end of method '<TestTask>d__1'::.ctor .method private final hidebysig virtual newslot instance void MoveNext() cil managed { .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::MoveNext() .maxstack 3 .locals init ( [0] int32 V_0, [1] int32 V_1, [2] valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter V_2, [3] class ValueTaskResearch.Program/'<TestTask>d__1' V_3, [4] class [System.Runtime]System.Exception V_4 ) IL_0000: ldarg.0 // this IL_0001: ldfld int32 ValueTaskResearch.Program/'<TestTask>d__1'::'<>1__state' IL_0006: stloc.0 // V_0 .try { IL_0007: ldloc.0 // V_0 IL_0008: brfalse.s IL_000c IL_000a: br.s IL_000e IL_000c: br.s IL_0049 // [16 9 - 16 10] IL_000e: nop // [17 13 - 17 35] IL_000f: ldc.i4.s 100 // 0x64 IL_0011: call class [System.Runtime]System.Threading.Tasks.Task [System.Runtime]System.Threading.Tasks.Task::Delay(int32) IL_0016: callvirt instance valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter [System.Runtime]System.Threading.Tasks.Task::GetAwaiter() IL_001b: stloc.2 // V_2 IL_001c: ldloca.s V_2 IL_001e: call instance bool [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter::get_IsCompleted() IL_0023: brtrue.s IL_0065 IL_0025: ldarg.0 // this IL_0026: ldc.i4.0 IL_0027: dup IL_0028: stloc.0 // V_0 IL_0029: stfld int32 ValueTaskResearch.Program/'<TestTask>d__1'::'<>1__state' IL_002e: ldarg.0 // this IL_002f: ldloc.2 // V_2 IL_0030: stfld valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter ValueTaskResearch.Program/'<TestTask>d__1'::'<>u__1' IL_0035: ldarg.0 // this IL_0036: stloc.3 // V_3 IL_0037: ldarg.0 // this IL_0038: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestTask>d__1'::'<>t__builder' IL_003d: ldloca.s V_2 IL_003f: ldloca.s V_3 IL_0041: call instance void valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32>::AwaitUnsafeOnCompleted<valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter, class ValueTaskResearch.Program/'<TestTask>d__1'>(!!0/*valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter*/&, !!1/*class ValueTaskResearch.Program/'<TestTask>d__1'*/&) IL_0046: nop IL_0047: leave.s IL_00a1 IL_0049: ldarg.0 // this IL_004a: ldfld valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter ValueTaskResearch.Program/'<TestTask>d__1'::'<>u__1' IL_004f: stloc.2 // V_2 IL_0050: ldarg.0 // this IL_0051: ldflda valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter ValueTaskResearch.Program/'<TestTask>d__1'::'<>u__1' IL_0056: initobj [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter IL_005c: ldarg.0 // this IL_005d: ldc.i4.m1 IL_005e: dup IL_005f: stloc.0 // V_0 IL_0060: stfld int32 ValueTaskResearch.Program/'<TestTask>d__1'::'<>1__state' IL_0065: ldloca.s V_2 IL_0067: call instance void [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter::GetResult() IL_006c: nop // [19 13 - 19 24] IL_006d: ldc.i4.s 100 // 0x64 IL_006f: stloc.1 // V_1 IL_0070: leave.s IL_008c } // end of .try catch [System.Runtime]System.Exception { IL_0072: stloc.s V_4 IL_0074: ldarg.0 // this IL_0075: ldc.i4.s -2 // 0xfe IL_0077: stfld int32 ValueTaskResearch.Program/'<TestTask>d__1'::'<>1__state' IL_007c: ldarg.0 // this IL_007d: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestTask>d__1'::'<>t__builder' IL_0082: ldloc.s V_4 IL_0084: call instance void valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32>::SetException(class [System.Runtime]System.Exception) IL_0089: nop IL_008a: leave.s IL_00a1 } // end of catch // [20 9 - 20 10] IL_008c: ldarg.0 // this IL_008d: ldc.i4.s -2 // 0xfe IL_008f: stfld int32 ValueTaskResearch.Program/'<TestTask>d__1'::'<>1__state' IL_0094: ldarg.0 // this IL_0095: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestTask>d__1'::'<>t__builder' IL_009a: ldloc.1 // V_1 IL_009b: call instance void valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32>::SetResult(!0/*int32*/) IL_00a0: nop IL_00a1: ret } // end of method '<TestTask>d__1'::MoveNext .method private final hidebysig virtual newslot instance void SetStateMachine( class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine stateMachine ) cil managed { .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerHiddenAttribute::.ctor() = (01 00 00 00 ) .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::SetStateMachine(class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine) .maxstack 8 IL_0000: ret } // end of method '<TestTask>d__1'::SetStateMachine } // end of class '<TestTask>d__1' .method private hidebysig static class [System.Runtime]System.Threading.Tasks.Task Main() cil managed { .custom instance void [System.Runtime]System.Runtime.CompilerServices.AsyncStateMachineAttribute::.ctor(class [System.Runtime]System.Type) = ( 01 00 24 56 61 6c 75 65 54 61 73 6b 52 65 73 65 // ..$ValueTaskRese 61 72 63 68 2e 50 72 6f 67 72 61 6d 2b 3c 4d 61 // arch.Program+<Ma 69 6e 3e 64 5f 5f 30 00 00 // in>d__0.. ) // type(class ValueTaskResearch.Program/'<Main>d__0') .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerStepThroughAttribute::.ctor() = (01 00 00 00 ) .maxstack 2 .locals init ( [0] class ValueTaskResearch.Program/'<Main>d__0' V_0, [1] valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder V_1 ) IL_0000: newobj instance void ValueTaskResearch.Program/'<Main>d__0'::.ctor() IL_0005: stloc.0 // V_0 IL_0006: ldloc.0 // V_0 IL_0007: call valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::Create() IL_000c: stfld valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_0011: ldloc.0 // V_0 IL_0012: ldc.i4.m1 IL_0013: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0018: ldloc.0 // V_0 IL_0019: ldfld valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_001e: stloc.1 // V_1 IL_001f: ldloca.s V_1 IL_0021: ldloca.s V_0 IL_0023: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::Start<class ValueTaskResearch.Program/'<Main>d__0'>(!!0/*class ValueTaskResearch.Program/'<Main>d__0'*/&) IL_0028: ldloc.0 // V_0 IL_0029: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_002e: call instance class [System.Runtime]System.Threading.Tasks.Task [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::get_Task() IL_0033: ret } // end of method Program::Main .method private hidebysig static class [System.Runtime]System.Threading.Tasks.Task`1<int32> TestTask() cil managed { .custom instance void [System.Runtime]System.Runtime.CompilerServices.AsyncStateMachineAttribute::.ctor(class [System.Runtime]System.Type) = ( 01 00 28 56 61 6c 75 65 54 61 73 6b 52 65 73 65 // ..(ValueTaskRese 61 72 63 68 2e 50 72 6f 67 72 61 6d 2b 3c 54 65 // arch.Program+<Te 73 74 54 61 73 6b 3e 64 5f 5f 31 00 00 // stTask>d__1.. ) // type(class ValueTaskResearch.Program/'<TestTask>d__1') .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerStepThroughAttribute::.ctor() = (01 00 00 00 ) .maxstack 2 .locals init ( [0] class ValueTaskResearch.Program/'<TestTask>d__1' V_0, [1] valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32> V_1 ) IL_0000: newobj instance void ValueTaskResearch.Program/'<TestTask>d__1'::.ctor() IL_0005: stloc.0 // V_0 IL_0006: ldloc.0 // V_0 IL_0007: call valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<!0/*int32*/> valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32>::Create() IL_000c: stfld valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestTask>d__1'::'<>t__builder' IL_0011: ldloc.0 // V_0 IL_0012: ldc.i4.m1 IL_0013: stfld int32 ValueTaskResearch.Program/'<TestTask>d__1'::'<>1__state' IL_0018: ldloc.0 // V_0 IL_0019: ldfld valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestTask>d__1'::'<>t__builder' IL_001e: stloc.1 // V_1 IL_001f: ldloca.s V_1 IL_0021: ldloca.s V_0 IL_0023: call instance void valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32>::Start<class ValueTaskResearch.Program/'<TestTask>d__1'>(!!0/*class ValueTaskResearch.Program/'<TestTask>d__1'*/&) IL_0028: ldloc.0 // V_0 IL_0029: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestTask>d__1'::'<>t__builder' IL_002e: call instance class [System.Runtime]System.Threading.Tasks.Task`1<!0/*int32*/> valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<int32>::get_Task() IL_0033: ret } // end of method Program::TestTask .method public hidebysig specialname rtspecialname instance void .ctor() cil managed { .maxstack 8 IL_0000: ldarg.0 // this IL_0001: call instance void [System.Runtime]System.Object::.ctor() IL_0006: nop IL_0007: ret } // end of method Program::.ctor .method private hidebysig static specialname void '<Main>'() cil managed { .entrypoint .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerStepThroughAttribute::.ctor() = (01 00 00 00 ) .maxstack 1 .locals init ( [0] valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter V_0 ) IL_0000: call class [System.Runtime]System.Threading.Tasks.Task ValueTaskResearch.Program::Main() IL_0005: callvirt instance valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter [System.Runtime]System.Threading.Tasks.Task::GetAwaiter() IL_000a: stloc.0 // V_0 IL_000b: ldloca.s V_0 IL_000d: call instance void [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter::GetResult() IL_0012: ret } // end of method Program::'<Main>' } // end of class ValueTaskResearch.Programasync ValueTask<int>Collapse or Expand
// Type: ValueTaskResearch.Program // Assembly: ValueTaskResearch, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null // MVID: EA74DFC9-6E5E-4DC8-B7FC-A47B369C42E7 // Location: /Users/yowko.tsai/ValueTaskResearch/ValueTaskResearch/bin/Debug/netcoreapp2.2/ValueTaskResearch.dll // Sequence point data from /Users/yowko.tsai/ValueTaskResearch/ValueTaskResearch/bin/Debug/netcoreapp2.2/ValueTaskResearch.pdb .class private auto ansi beforefieldinit ValueTaskResearch.Program extends [System.Runtime]System.Object { .class nested private sealed auto ansi beforefieldinit '<Main>d__0' extends [System.Runtime]System.Object implements [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine { .custom instance void [System.Runtime]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = (01 00 00 00 ) .field public int32 '<>1__state' .field public valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder '<>t__builder' .field private valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> '<>u__1' .method public hidebysig specialname rtspecialname instance void .ctor() cil managed { .maxstack 8 IL_0000: ldarg.0 // this IL_0001: call instance void [System.Runtime]System.Object::.ctor() IL_0006: nop IL_0007: ret } // end of method '<Main>d__0'::.ctor .method private final hidebysig virtual newslot instance void MoveNext() cil managed { .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::MoveNext() .maxstack 3 .locals init ( [0] int32 V_0, [1] valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> V_1, [2] valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32> V_2, [3] class ValueTaskResearch.Program/'<Main>d__0' V_3, [4] class [System.Runtime]System.Exception V_4 ) IL_0000: ldarg.0 // this IL_0001: ldfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0006: stloc.0 // V_0 .try { IL_0007: ldloc.0 // V_0 IL_0008: brfalse.s IL_000c IL_000a: br.s IL_000e IL_000c: br.s IL_004a // [8 9 - 8 10] IL_000e: nop // [10 13 - 10 35] IL_000f: call valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32> ValueTaskResearch.Program::TestValueTask() IL_0014: stloc.2 // V_2 IL_0015: ldloca.s V_2 IL_0017: call instance valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<!0/*int32*/> valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32>::GetAwaiter() IL_001c: stloc.1 // V_1 IL_001d: ldloca.s V_1 IL_001f: call instance bool valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32>::get_IsCompleted() IL_0024: brtrue.s IL_0066 IL_0026: ldarg.0 // this IL_0027: ldc.i4.0 IL_0028: dup IL_0029: stloc.0 // V_0 IL_002a: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_002f: ldarg.0 // this IL_0030: ldloc.1 // V_1 IL_0031: stfld valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> ValueTaskResearch.Program/'<Main>d__0'::'<>u__1' IL_0036: ldarg.0 // this IL_0037: stloc.3 // V_3 IL_0038: ldarg.0 // this IL_0039: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_003e: ldloca.s V_1 IL_0040: ldloca.s V_3 IL_0042: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::AwaitUnsafeOnCompleted<valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32>, class ValueTaskResearch.Program/'<Main>d__0'>(!!0/*valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32>*/&, !!1/*class ValueTaskResearch.Program/'<Main>d__0'*/&) IL_0047: nop IL_0048: leave.s IL_009e IL_004a: ldarg.0 // this IL_004b: ldfld valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> ValueTaskResearch.Program/'<Main>d__0'::'<>u__1' IL_0050: stloc.1 // V_1 IL_0051: ldarg.0 // this IL_0052: ldflda valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> ValueTaskResearch.Program/'<Main>d__0'::'<>u__1' IL_0057: initobj valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> IL_005d: ldarg.0 // this IL_005e: ldc.i4.m1 IL_005f: dup IL_0060: stloc.0 // V_0 IL_0061: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0066: ldloca.s V_1 IL_0068: call instance !0/*int32*/ valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32>::GetResult() IL_006d: pop IL_006e: leave.s IL_008a } // end of .try catch [System.Runtime]System.Exception { IL_0070: stloc.s V_4 IL_0072: ldarg.0 // this IL_0073: ldc.i4.s -2 // 0xfe IL_0075: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_007a: ldarg.0 // this IL_007b: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_0080: ldloc.s V_4 IL_0082: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::SetException(class [System.Runtime]System.Exception) IL_0087: nop IL_0088: leave.s IL_009e } // end of catch // [12 9 - 12 10] IL_008a: ldarg.0 // this IL_008b: ldc.i4.s -2 // 0xfe IL_008d: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0092: ldarg.0 // this IL_0093: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_0098: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::SetResult() IL_009d: nop IL_009e: ret } // end of method '<Main>d__0'::MoveNext .method private final hidebysig virtual newslot instance void SetStateMachine( class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine stateMachine ) cil managed { .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerHiddenAttribute::.ctor() = (01 00 00 00 ) .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::SetStateMachine(class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine) .maxstack 8 IL_0000: ret } // end of method '<Main>d__0'::SetStateMachine } // end of class '<Main>d__0' .class nested private sealed auto ansi beforefieldinit '<TestValueTask>d__1' extends [System.Runtime]System.Object implements [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine { .custom instance void [System.Runtime]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = (01 00 00 00 ) .field public int32 '<>1__state' .field public valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32> '<>t__builder' .field private valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter '<>u__1' .method public hidebysig specialname rtspecialname instance void .ctor() cil managed { .maxstack 8 IL_0000: ldarg.0 // this IL_0001: call instance void [System.Runtime]System.Object::.ctor() IL_0006: nop IL_0007: ret } // end of method '<TestValueTask>d__1'::.ctor .method private final hidebysig virtual newslot instance void MoveNext() cil managed { .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::MoveNext() .maxstack 3 .locals init ( [0] int32 V_0, [1] int32 V_1, [2] valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter V_2, [3] class ValueTaskResearch.Program/'<TestValueTask>d__1' V_3, [4] class [System.Runtime]System.Exception V_4 ) IL_0000: ldarg.0 // this IL_0001: ldfld int32 ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>1__state' IL_0006: stloc.0 // V_0 .try { IL_0007: ldloc.0 // V_0 IL_0008: brfalse.s IL_000c IL_000a: br.s IL_000e IL_000c: br.s IL_0049 // [22 9 - 22 10] IL_000e: nop // [23 13 - 23 35] IL_000f: ldc.i4.s 100 // 0x64 IL_0011: call class [System.Runtime]System.Threading.Tasks.Task [System.Runtime]System.Threading.Tasks.Task::Delay(int32) IL_0016: callvirt instance valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter [System.Runtime]System.Threading.Tasks.Task::GetAwaiter() IL_001b: stloc.2 // V_2 IL_001c: ldloca.s V_2 IL_001e: call instance bool [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter::get_IsCompleted() IL_0023: brtrue.s IL_0065 IL_0025: ldarg.0 // this IL_0026: ldc.i4.0 IL_0027: dup IL_0028: stloc.0 // V_0 IL_0029: stfld int32 ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>1__state' IL_002e: ldarg.0 // this IL_002f: ldloc.2 // V_2 IL_0030: stfld valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>u__1' IL_0035: ldarg.0 // this IL_0036: stloc.3 // V_3 IL_0037: ldarg.0 // this IL_0038: ldflda valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>t__builder' IL_003d: ldloca.s V_2 IL_003f: ldloca.s V_3 IL_0041: call instance void valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32>::AwaitUnsafeOnCompleted<valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter, class ValueTaskResearch.Program/'<TestValueTask>d__1'>(!!0/*valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter*/&, !!1/*class ValueTaskResearch.Program/'<TestValueTask>d__1'*/&) IL_0046: nop IL_0047: leave.s IL_00a1 IL_0049: ldarg.0 // this IL_004a: ldfld valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>u__1' IL_004f: stloc.2 // V_2 IL_0050: ldarg.0 // this IL_0051: ldflda valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>u__1' IL_0056: initobj [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter IL_005c: ldarg.0 // this IL_005d: ldc.i4.m1 IL_005e: dup IL_005f: stloc.0 // V_0 IL_0060: stfld int32 ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>1__state' IL_0065: ldloca.s V_2 IL_0067: call instance void [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter::GetResult() IL_006c: nop // [25 13 - 25 23] IL_006d: ldc.i4.s 10 // 0x0a IL_006f: stloc.1 // V_1 IL_0070: leave.s IL_008c } // end of .try catch [System.Runtime]System.Exception { IL_0072: stloc.s V_4 IL_0074: ldarg.0 // this IL_0075: ldc.i4.s -2 // 0xfe IL_0077: stfld int32 ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>1__state' IL_007c: ldarg.0 // this IL_007d: ldflda valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>t__builder' IL_0082: ldloc.s V_4 IL_0084: call instance void valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32>::SetException(class [System.Runtime]System.Exception) IL_0089: nop IL_008a: leave.s IL_00a1 } // end of catch // [26 9 - 26 10] IL_008c: ldarg.0 // this IL_008d: ldc.i4.s -2 // 0xfe IL_008f: stfld int32 ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>1__state' IL_0094: ldarg.0 // this IL_0095: ldflda valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>t__builder' IL_009a: ldloc.1 // V_1 IL_009b: call instance void valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32>::SetResult(!0/*int32*/) IL_00a0: nop IL_00a1: ret } // end of method '<TestValueTask>d__1'::MoveNext .method private final hidebysig virtual newslot instance void SetStateMachine( class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine stateMachine ) cil managed { .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerHiddenAttribute::.ctor() = (01 00 00 00 ) .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::SetStateMachine(class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine) .maxstack 8 IL_0000: ret } // end of method '<TestValueTask>d__1'::SetStateMachine } // end of class '<TestValueTask>d__1' .method private hidebysig static class [System.Runtime]System.Threading.Tasks.Task Main() cil managed { .custom instance void [System.Runtime]System.Runtime.CompilerServices.AsyncStateMachineAttribute::.ctor(class [System.Runtime]System.Type) = ( 01 00 24 56 61 6c 75 65 54 61 73 6b 52 65 73 65 // ..$ValueTaskRese 61 72 63 68 2e 50 72 6f 67 72 61 6d 2b 3c 4d 61 // arch.Program+<Ma 69 6e 3e 64 5f 5f 30 00 00 // in>d__0.. ) // type(class ValueTaskResearch.Program/'<Main>d__0') .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerStepThroughAttribute::.ctor() = (01 00 00 00 ) .maxstack 2 .locals init ( [0] class ValueTaskResearch.Program/'<Main>d__0' V_0, [1] valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder V_1 ) IL_0000: newobj instance void ValueTaskResearch.Program/'<Main>d__0'::.ctor() IL_0005: stloc.0 // V_0 IL_0006: ldloc.0 // V_0 IL_0007: call valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::Create() IL_000c: stfld valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_0011: ldloc.0 // V_0 IL_0012: ldc.i4.m1 IL_0013: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0018: ldloc.0 // V_0 IL_0019: ldfld valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_001e: stloc.1 // V_1 IL_001f: ldloca.s V_1 IL_0021: ldloca.s V_0 IL_0023: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::Start<class ValueTaskResearch.Program/'<Main>d__0'>(!!0/*class ValueTaskResearch.Program/'<Main>d__0'*/&) IL_0028: ldloc.0 // V_0 IL_0029: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_002e: call instance class [System.Runtime]System.Threading.Tasks.Task [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::get_Task() IL_0033: ret } // end of method Program::Main .method private hidebysig static valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32> TestValueTask() cil managed { .custom instance void [System.Runtime]System.Runtime.CompilerServices.AsyncStateMachineAttribute::.ctor(class [System.Runtime]System.Type) = ( 01 00 2d 56 61 6c 75 65 54 61 73 6b 52 65 73 65 // ..-ValueTaskRese 61 72 63 68 2e 50 72 6f 67 72 61 6d 2b 3c 54 65 // arch.Program+<Te 73 74 56 61 6c 75 65 54 61 73 6b 3e 64 5f 5f 31 // stValueTask>d__1 00 00 // .. ) // type(class ValueTaskResearch.Program/'<TestValueTask>d__1') .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerStepThroughAttribute::.ctor() = (01 00 00 00 ) .maxstack 2 .locals init ( [0] class ValueTaskResearch.Program/'<TestValueTask>d__1' V_0, [1] valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32> V_1 ) IL_0000: newobj instance void ValueTaskResearch.Program/'<TestValueTask>d__1'::.ctor() IL_0005: stloc.0 // V_0 IL_0006: ldloc.0 // V_0 IL_0007: call valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<!0/*int32*/> valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32>::Create() IL_000c: stfld valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>t__builder' IL_0011: ldloc.0 // V_0 IL_0012: ldc.i4.m1 IL_0013: stfld int32 ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>1__state' IL_0018: ldloc.0 // V_0 IL_0019: ldfld valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>t__builder' IL_001e: stloc.1 // V_1 IL_001f: ldloca.s V_1 IL_0021: ldloca.s V_0 IL_0023: call instance void valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32>::Start<class ValueTaskResearch.Program/'<TestValueTask>d__1'>(!!0/*class ValueTaskResearch.Program/'<TestValueTask>d__1'*/&) IL_0028: ldloc.0 // V_0 IL_0029: ldflda valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32> ValueTaskResearch.Program/'<TestValueTask>d__1'::'<>t__builder' IL_002e: call instance valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<!0/*int32*/> valuetype [System.Runtime]System.Runtime.CompilerServices.AsyncValueTaskMethodBuilder`1<int32>::get_Task() IL_0033: ret } // end of method Program::TestValueTask .method public hidebysig specialname rtspecialname instance void .ctor() cil managed { .maxstack 8 IL_0000: ldarg.0 // this IL_0001: call instance void [System.Runtime]System.Object::.ctor() IL_0006: nop IL_0007: ret } // end of method Program::.ctor .method private hidebysig static specialname void '<Main>'() cil managed { .entrypoint .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerStepThroughAttribute::.ctor() = (01 00 00 00 ) .maxstack 1 .locals init ( [0] valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter V_0 ) IL_0000: call class [System.Runtime]System.Threading.Tasks.Task ValueTaskResearch.Program::Main() IL_0005: callvirt instance valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter [System.Runtime]System.Threading.Tasks.Task::GetAwaiter() IL_000a: stloc.0 // V_0 IL_000b: ldloca.s V_0 IL_000d: call instance void [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter::GetResult() IL_0012: ret } // end of method Program::'<Main>' } // end of class ValueTaskResearch.ProgramValueTask<int>Collapse or Expand
// Type: ValueTaskResearch.Program // Assembly: ValueTaskResearch, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null // MVID: 16376FF2-3379-4D36-AE5C-65DF961109C2 // Location: /Users/yowko.tsai/ValueTaskResearch/ValueTaskResearch/bin/Debug/netcoreapp2.2/ValueTaskResearch.dll // Sequence point data from /Users/yowko.tsai/ValueTaskResearch/ValueTaskResearch/bin/Debug/netcoreapp2.2/ValueTaskResearch.pdb .class private auto ansi beforefieldinit ValueTaskResearch.Program extends [System.Runtime]System.Object { .class nested private sealed auto ansi beforefieldinit '<Main>d__0' extends [System.Runtime]System.Object implements [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine { .custom instance void [System.Runtime]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = (01 00 00 00 ) .field public int32 '<>1__state' .field public valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder '<>t__builder' .field private valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> '<>u__1' .method public hidebysig specialname rtspecialname instance void .ctor() cil managed { .maxstack 8 IL_0000: ldarg.0 // this IL_0001: call instance void [System.Runtime]System.Object::.ctor() IL_0006: nop IL_0007: ret } // end of method '<Main>d__0'::.ctor .method private final hidebysig virtual newslot instance void MoveNext() cil managed { .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::MoveNext() .maxstack 3 .locals init ( [0] int32 V_0, [1] valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> V_1, [2] valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32> V_2, [3] class ValueTaskResearch.Program/'<Main>d__0' V_3, [4] class [System.Runtime]System.Exception V_4 ) IL_0000: ldarg.0 // this IL_0001: ldfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0006: stloc.0 // V_0 .try { IL_0007: ldloc.0 // V_0 IL_0008: brfalse.s IL_000c IL_000a: br.s IL_000e IL_000c: br.s IL_004a // [8 9 - 8 10] IL_000e: nop // [11 13 - 11 42] IL_000f: call valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32> ValueTaskResearch.Program::TestValueTaskWithNew() IL_0014: stloc.2 // V_2 IL_0015: ldloca.s V_2 IL_0017: call instance valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<!0/*int32*/> valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32>::GetAwaiter() IL_001c: stloc.1 // V_1 IL_001d: ldloca.s V_1 IL_001f: call instance bool valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32>::get_IsCompleted() IL_0024: brtrue.s IL_0066 IL_0026: ldarg.0 // this IL_0027: ldc.i4.0 IL_0028: dup IL_0029: stloc.0 // V_0 IL_002a: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_002f: ldarg.0 // this IL_0030: ldloc.1 // V_1 IL_0031: stfld valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> ValueTaskResearch.Program/'<Main>d__0'::'<>u__1' IL_0036: ldarg.0 // this IL_0037: stloc.3 // V_3 IL_0038: ldarg.0 // this IL_0039: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_003e: ldloca.s V_1 IL_0040: ldloca.s V_3 IL_0042: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::AwaitUnsafeOnCompleted<valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32>, class ValueTaskResearch.Program/'<Main>d__0'>(!!0/*valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32>*/&, !!1/*class ValueTaskResearch.Program/'<Main>d__0'*/&) IL_0047: nop IL_0048: leave.s IL_009e IL_004a: ldarg.0 // this IL_004b: ldfld valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> ValueTaskResearch.Program/'<Main>d__0'::'<>u__1' IL_0050: stloc.1 // V_1 IL_0051: ldarg.0 // this IL_0052: ldflda valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> ValueTaskResearch.Program/'<Main>d__0'::'<>u__1' IL_0057: initobj valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32> IL_005d: ldarg.0 // this IL_005e: ldc.i4.m1 IL_005f: dup IL_0060: stloc.0 // V_0 IL_0061: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0066: ldloca.s V_1 IL_0068: call instance !0/*int32*/ valuetype [System.Runtime]System.Runtime.CompilerServices.ValueTaskAwaiter`1<int32>::GetResult() IL_006d: pop IL_006e: leave.s IL_008a } // end of .try catch [System.Runtime]System.Exception { IL_0070: stloc.s V_4 IL_0072: ldarg.0 // this IL_0073: ldc.i4.s -2 // 0xfe IL_0075: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_007a: ldarg.0 // this IL_007b: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_0080: ldloc.s V_4 IL_0082: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::SetException(class [System.Runtime]System.Exception) IL_0087: nop IL_0088: leave.s IL_009e } // end of catch // [12 9 - 12 10] IL_008a: ldarg.0 // this IL_008b: ldc.i4.s -2 // 0xfe IL_008d: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0092: ldarg.0 // this IL_0093: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_0098: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::SetResult() IL_009d: nop IL_009e: ret } // end of method '<Main>d__0'::MoveNext .method private final hidebysig virtual newslot instance void SetStateMachine( class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine stateMachine ) cil managed { .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerHiddenAttribute::.ctor() = (01 00 00 00 ) .override method instance void [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine::SetStateMachine(class [System.Runtime]System.Runtime.CompilerServices.IAsyncStateMachine) .maxstack 8 IL_0000: ret } // end of method '<Main>d__0'::SetStateMachine } // end of class '<Main>d__0' .method private hidebysig static class [System.Runtime]System.Threading.Tasks.Task Main() cil managed { .custom instance void [System.Runtime]System.Runtime.CompilerServices.AsyncStateMachineAttribute::.ctor(class [System.Runtime]System.Type) = ( 01 00 24 56 61 6c 75 65 54 61 73 6b 52 65 73 65 // ..$ValueTaskRese 61 72 63 68 2e 50 72 6f 67 72 61 6d 2b 3c 4d 61 // arch.Program+<Ma 69 6e 3e 64 5f 5f 30 00 00 // in>d__0.. ) // type(class ValueTaskResearch.Program/'<Main>d__0') .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerStepThroughAttribute::.ctor() = (01 00 00 00 ) .maxstack 2 .locals init ( [0] class ValueTaskResearch.Program/'<Main>d__0' V_0, [1] valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder V_1 ) IL_0000: newobj instance void ValueTaskResearch.Program/'<Main>d__0'::.ctor() IL_0005: stloc.0 // V_0 IL_0006: ldloc.0 // V_0 IL_0007: call valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::Create() IL_000c: stfld valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_0011: ldloc.0 // V_0 IL_0012: ldc.i4.m1 IL_0013: stfld int32 ValueTaskResearch.Program/'<Main>d__0'::'<>1__state' IL_0018: ldloc.0 // V_0 IL_0019: ldfld valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_001e: stloc.1 // V_1 IL_001f: ldloca.s V_1 IL_0021: ldloca.s V_0 IL_0023: call instance void [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::Start<class ValueTaskResearch.Program/'<Main>d__0'>(!!0/*class ValueTaskResearch.Program/'<Main>d__0'*/&) IL_0028: ldloc.0 // V_0 IL_0029: ldflda valuetype [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder ValueTaskResearch.Program/'<Main>d__0'::'<>t__builder' IL_002e: call instance class [System.Runtime]System.Threading.Tasks.Task [System.Threading.Tasks]System.Runtime.CompilerServices.AsyncTaskMethodBuilder::get_Task() IL_0033: ret } // end of method Program::Main .method private hidebysig static valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32> TestValueTaskWithNew() cil managed { .maxstack 1 .locals init ( [0] valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32> V_0 ) // [29 9 - 29 10] IL_0000: nop // [30 13 - 30 42] IL_0001: ldc.i4.0 IL_0002: newobj instance void valuetype [System.Runtime]System.Threading.Tasks.ValueTask`1<int32>::.ctor(!0/*int32*/) IL_0007: stloc.0 // V_0 IL_0008: br.s IL_000a // [31 9 - 31 10] IL_000a: ldloc.0 // V_0 IL_000b: ret } // end of method Program::TestValueTaskWithNew .method public hidebysig specialname rtspecialname instance void .ctor() cil managed { .maxstack 8 IL_0000: ldarg.0 // this IL_0001: call instance void [System.Runtime]System.Object::.ctor() IL_0006: nop IL_0007: ret } // end of method Program::.ctor .method private hidebysig static specialname void '<Main>'() cil managed { .entrypoint .custom instance void [System.Diagnostics.Debug]System.Diagnostics.DebuggerStepThroughAttribute::.ctor() = (01 00 00 00 ) .maxstack 1 .locals init ( [0] valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter V_0 ) IL_0000: call class [System.Runtime]System.Threading.Tasks.Task ValueTaskResearch.Program::Main() IL_0005: callvirt instance valuetype [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter [System.Runtime]System.Threading.Tasks.Task::GetAwaiter() IL_000a: stloc.0 // V_0 IL_000b: ldloca.s V_0 IL_000d: call instance void [System.Runtime]System.Runtime.CompilerServices.TaskAwaiter::GetResult() IL_0012: ret } // end of method Program::'<Main>' } // end of class ValueTaskResearch.Program
心得
看完 IL 後是不是一切豁然開朗 ？！ 說實話我個人是沒有這種感覺啦 XD
所幸在 C# Language ValueTask 找到我個人可以接受的說明：
過去的在實作 async 卻希望使用同步呼叫時會需要使用
Task.Run或Task.FromResult，無形之中就造成效能耗損，而ValueTask可同時用於 同步實作 (Synchronous implementation) 與 非同步實作 (Asynchronous implementation)
同步實作 (Synchronous implementation)同步方法適用，方法簽章中沒有
async，方法中沒有用到await，就需要new ValueTask來傳遞回傳值private static ValueTask<int> TestValueTaskWithNew() { return new ValueTask<int>(0); }非同步實作 (Asynchronous implementation)非同步方法適用，方法簽章中有
async，方法中有用到await，可以直傳回傳 value type，不需要new ValueTaskprivate static async ValueTask<int> TestValueTask() { await Task.Delay(100); return 10; }
記了這麼多，好像都是廢話，但小弟資質駑鈍，就麻煩各位大大提點了 ~~~~
參考資訊
文章作者 Yowko Tsai
上次更新 2021-11-02
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