667579-DebuggerHidden iterator methods should hide MoveNext (changeset 1310286)

Src/Compilers/CSharp/Portable/Lowering/AsyncRewriter/AsyncRewriter.cs

@@ -90,13 +90,13 @@ protected override void GenerateMethodImplementations()
             var IAsyncStateMachine_SetStateMachine = F.WellKnownMethod(WellKnownMember.System_Runtime_CompilerServices_IAsyncStateMachine_SetStateMachine);
 
             // Add IAsyncStateMachine.MoveNext()
-            
-            var moveNextMethod = OpenMethodImplementation(IAsyncStateMachine_MoveNext, "MoveNext", asyncKickoffMethod: this.method, hasMethodBodyDependency: true);
+
+            var moveNextMethod = OpenMethodImplementation(IAsyncStateMachine_MoveNext, "MoveNext", asyncKickoffMethod: this.method, hasMethodBodyDependency: true, debuggerHidden: IsDebuggerHidden(this.method), generateDebugInfo: true);
             GenerateMoveNext(moveNextMethod);
 
             // Add IAsyncStateMachine.SetStateMachine()
             
-            OpenMethodImplementation(IAsyncStateMachine_SetStateMachine, "SetStateMachine", debuggerHidden: true, hasMethodBodyDependency: false);
+            OpenMethodImplementation(IAsyncStateMachine_SetStateMachine, "SetStateMachine", debuggerHidden: true, generateDebugInfo: false, hasMethodBodyDependency: false);
 
             // SetStateMachine is used to initialize the underlying AsyncMethodBuilder's reference to the boxed copy of the state machine.
             // If the state machine is a class there is no copy made and thus the initialization is not necessary. 

Src/Compilers/CSharp/Portable/Lowering/IteratorRewriter/IteratorRewriter.cs

@@ -134,8 +134,8 @@ private void GenerateEnumeratorImplementation()
 
             // Add bool IEnumerator.MoveNext() and void IDisposable.Dispose()
             {
-                var disposeMethod = OpenMethodImplementation(IDisposable_Dispose, debuggerHidden: true, hasMethodBodyDependency: true);
-                var moveNextMethod = OpenMethodImplementation(IEnumerator_MoveNext, methodName: WellKnownMemberNames.MoveNextMethodName, hasMethodBodyDependency: true);
+                var disposeMethod = OpenMethodImplementation(IDisposable_Dispose, debuggerHidden: true, generateDebugInfo: false, hasMethodBodyDependency: true);
+                var moveNextMethod = OpenMethodImplementation(IEnumerator_MoveNext, methodName: WellKnownMemberNames.MoveNextMethodName, hasMethodBodyDependency: true, debuggerHidden: IsDebuggerHidden(this.method));
                 GenerateMoveNextAndDispose(moveNextMethod, disposeMethod);
             }
 
@@ -147,7 +147,7 @@ private void GenerateEnumeratorImplementation()
 
             // Add void IEnumerator.Reset()
             {
-                OpenMethodImplementation(IEnumerator_Reset, debuggerHidden: true, hasMethodBodyDependency: false);
+                OpenMethodImplementation(IEnumerator_Reset, debuggerHidden: true, generateDebugInfo: false, hasMethodBodyDependency: false);
                 F.CloseMethod(F.Throw(F.New(F.WellKnownType(WellKnownType.System_NotSupportedException))));
             }
 
@@ -184,7 +184,7 @@ private void GenerateEnumerableImplementation(ref BoundExpression managedThreadI
              
             // The implementation doesn't depend on the method body of the iterator method.
             // Only on it's parameters and staticness.
-            var getEnumeratorGeneric = OpenMethodImplementation(IEnumerableOfElementType_GetEnumerator, debuggerHidden: true, hasMethodBodyDependency: false);
+            var getEnumeratorGeneric = OpenMethodImplementation(IEnumerableOfElementType_GetEnumerator, debuggerHidden: true, generateDebugInfo: false, hasMethodBodyDependency: false);
 
             var bodyBuilder = ArrayBuilder<BoundStatement>.GetInstance();
             var resultVariable = F.SynthesizedLocal(stateMachineClass, null);      // iteratorClass result;
@@ -263,7 +263,7 @@ private void GenerateEnumerableImplementation(ref BoundExpression managedThreadI
             F.CloseMethod(F.Block(ImmutableArray.Create(resultVariable), bodyBuilder.ToImmutableAndFree()));
 
             // Generate IEnumerable.GetEnumerator
-            var getEnumerator = OpenMethodImplementation(IEnumerable_GetEnumerator, debuggerHidden: true);
+            var getEnumerator = OpenMethodImplementation(IEnumerable_GetEnumerator, debuggerHidden: true, generateDebugInfo: false);
             F.CloseMethod(F.Return(F.Call(F.This(), getEnumeratorGeneric)));
         }
 

Src/Compilers/CSharp/Portable/Lowering/StateMachineRewriter/StateMachineRewriter.cs

@@ -247,11 +247,12 @@ private BoundStatement ReplaceOriginalMethod()
         protected SynthesizedImplementationMethod OpenMethodImplementation(
             MethodSymbol methodToImplement,
             string methodName = null,
-            bool debuggerHidden = false, 
+            bool debuggerHidden = false,
+            bool generateDebugInfo = true,
             bool hasMethodBodyDependency = false,
             MethodSymbol asyncKickoffMethod = null)
         {
-            var result = new SynthesizedStateMachineMethod(methodName, methodToImplement, F.CurrentClass, asyncKickoffMethod, null, debuggerHidden, hasMethodBodyDependency);
+            var result = new SynthesizedStateMachineMethod(methodName, methodToImplement, F.CurrentClass, asyncKickoffMethod, null, debuggerHidden, generateDebugInfo, hasMethodBodyDependency);
             F.ModuleBuilderOpt.AddSynthesizedDefinition(F.CurrentClass, result);
             F.CurrentMethod = result;
             return result;
@@ -271,5 +272,16 @@ private BoundStatement ReplaceOriginalMethod()
             F.CurrentMethod = getter;
             return getter;
         }
+
+        protected bool IsDebuggerHidden(MethodSymbol method)
+        {
+            var debuggerHiddenAttribute = this.compilationState.Compilation.GetWellKnownType(WellKnownType.System_Diagnostics_DebuggerHiddenAttribute);
+            foreach (var a in this.method.GetAttributes())
+            {
+                if (a.AttributeClass == debuggerHiddenAttribute) return true;
+            }
+
+            return false;
+        }
     }
 }
\ No newline at end of file

Src/Compilers/CSharp/Portable/Lowering/StateMachineRewriter/SynthesizedStateMachineMethod.cs

@@ -19,8 +19,9 @@ internal sealed class SynthesizedStateMachineMethod : SynthesizedImplementationM
             MethodSymbol asyncKickoffMethod,
             PropertySymbol associatedProperty,
             bool debuggerHidden,
+            bool generateDebugInfo,
             bool hasMethodBodyDependency)
-            : base(interfaceMethod, implementingType,  name, debuggerHidden, associatedProperty, asyncKickoffMethod)
+            : base(interfaceMethod, implementingType,  name, debuggerHidden, generateDebugInfo, associatedProperty, asyncKickoffMethod)
         {
             this.hasMethodBodyDependency = hasMethodBodyDependency;
         }

Src/Compilers/CSharp/Portable/Lowering/StateMachineRewriter/SynthesizedStateMachineProperty.cs

@@ -29,6 +29,7 @@ internal class SynthesizedStateMachineProperty : PropertySymbol, ISynthesizedMet
                 asyncKickoffMethod: null,
                 associatedProperty: this,
                 debuggerHidden: debuggerHidden,
+                generateDebugInfo: !debuggerHidden,
                 hasMethodBodyDependency: hasMethodBodyDependency);
         }
 

Src/Compilers/CSharp/Portable/Symbols/Synthesized/SynthesizedImplementationMethod.cs

@@ -14,6 +14,7 @@ internal class SynthesizedImplementationMethod : SynthesizedInstanceMethodSymbol
         private readonly MethodSymbol interfaceMethod;
         private readonly NamedTypeSymbol implementingType;
         private readonly bool debuggerHidden;
+        private readonly bool generateDebugInfo;
         private readonly PropertySymbol associatedProperty;
         private readonly MethodSymbol asyncKickoffMethod;
 
@@ -29,6 +30,7 @@ internal class SynthesizedImplementationMethod : SynthesizedInstanceMethodSymbol
             NamedTypeSymbol implementingType,
             string name = null,
             bool debuggerHidden = false,
+            bool generateDebugInfo = true,
             PropertySymbol associatedProperty = null,
             MethodSymbol asyncKickoffMethod = null)
         {
@@ -39,6 +41,7 @@ internal class SynthesizedImplementationMethod : SynthesizedInstanceMethodSymbol
             this.interfaceMethod = interfaceMethod;
             this.implementingType = implementingType;
             this.debuggerHidden = debuggerHidden;
+            this.generateDebugInfo = generateDebugInfo;
             this.associatedProperty = associatedProperty;
             this.explicitInterfaceImplementations = ImmutableArray.Create<MethodSymbol>(interfaceMethod);
             this.asyncKickoffMethod = asyncKickoffMethod;
@@ -100,7 +103,7 @@ internal sealed override void AddSynthesizedAttributes(ModuleCompilationState co
 
         internal override bool GenerateDebugInfo
         {
-            get { return !debuggerHidden; }
+            get { return generateDebugInfo; }
         }
 
         public sealed override ImmutableArray<TypeParameterSymbol> TypeParameters

Src/Compilers/CSharp/Test/Emit/PDB/PDBIteratorTests.cs

@@ -1009,6 +1009,54 @@ static IEnumerable<int> M()
       </scope>
     </method>
   </methods>
+</symbols>";
+            AssertXmlEqual(expected, actual);
+        }
+
+        [Fact, WorkItem(667579, "DevDiv")]
+        public void DebuggerHiddenIterator()
+        {
+            var text = @"
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+
+class C
+{
+    static void Main(string[] args)
+    {
+        foreach (var x in F()) ;
+    }
+
+    [DebuggerHidden]
+    static IEnumerable<int> F()
+    {
+        throw new Exception();
+        yield break;
+    }
+}";
+            string actual = GetPdbXml(text, TestOptions.DebugDll, "C+<F>d__0.MoveNext");
+            string expected =
+@"<?xml version=""1.0"" encoding=""utf-16""?>
+<symbols>
+  <methods>
+    <method containingType=""C+&lt;F&gt;d__0"" name=""MoveNext"" parameterNames="""">
+      <customDebugInfo version=""4"" count=""1"">
+        <forward version=""4"" kind=""ForwardInfo"" size=""12"" declaringType=""C"" methodName=""Main"" parameterNames=""args"" />
+      </customDebugInfo>
+      <sequencepoints total=""3"">
+        <entry il_offset=""0x0"" hidden=""true"" start_row=""16707566"" start_column=""0"" end_row=""16707566"" end_column=""0"" file_ref=""0"" />
+        <entry il_offset=""0x19"" start_row=""15"" start_column=""5"" end_row=""15"" end_column=""6"" file_ref=""0"" />
+        <entry il_offset=""0x1a"" start_row=""16"" start_column=""9"" end_row=""16"" end_column=""31"" file_ref=""0"" />
+      </sequencepoints>
+      <locals>
+        <local name=""CS$524$0000"" il_index=""0"" il_start=""0x0"" il_end=""0x20"" attributes=""1"" />
+      </locals>
+      <scope startOffset=""0x0"" endOffset=""0x20"">
+        <local name=""CS$524$0000"" il_index=""0"" il_start=""0x0"" il_end=""0x20"" attributes=""1"" />
+      </scope>
+    </method>
+  </methods>
 </symbols>";
             AssertXmlEqual(expected, actual);
         }

Src/Compilers/VisualBasic/Portable/Lowering/AsyncRewriter/AsyncRewriter.vb

@@ -30,7 +30,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                        asyncKind As AsyncMethodKind,
                        compilationState As TypeCompilationState,
                        diagnostics As DiagnosticBag,
-                       generateDebugInfo As boolean)
+                       generateDebugInfo As Boolean)
 
             MyBase.New(body, method, compilationState, diagnostics, generateDebugInfo)
 
@@ -62,10 +62,10 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
         End Sub
 
         Friend Shared Function CreateAsyncStateMachine(method As MethodSymbol,
-                                                       typeIndex As Integer,
+                                                                 typeIndex As Integer,
                                                        typeKind As TypeKind,
-                                                       valueTypeSymbol As NamedTypeSymbol,
-                                                       iAsyncStateMachine As NamedTypeSymbol) As NamedTypeSymbol
+                                                                 valueTypeSymbol As NamedTypeSymbol,
+                                                                 iAsyncStateMachine As NamedTypeSymbol) As NamedTypeSymbol
 
             Return New AsyncStateMachine(method, typeIndex, typeKind, valueTypeSymbol, iAsyncStateMachine)
         End Function
@@ -133,14 +133,14 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                                                  method As MethodSymbol,
                                                  compilationState As TypeCompilationState,
                                                  diagnostics As DiagnosticBag,
-                                                 generateDebugInfo As boolean) As BoundBlock
+                                                 generateDebugInfo As Boolean) As BoundBlock
 
             If body.HasErrors Then
                 Return body
             End If
 
             Dim asyncMethodKind As AsyncMethodKind = GetAsyncMethodKind(method)
-            If asyncMethodKind = asyncMethodKind.None Then
+            If asyncMethodKind = AsyncMethodKind.None Then
                 Return body
             End If
 
@@ -156,10 +156,13 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
 
         Protected Overrides Sub GenerateMethodImplementations()
             ' Add IAsyncStateMachine.MoveNext()
+            Dim debuggerHidden = IsDebuggerHidden(Me.Method)
+            Dim moveNextAttrs As DebugAttributes = DebugAttributes.CompilerGeneratedAttribute
+            If debuggerHidden Then moveNextAttrs = moveNextAttrs Or DebugAttributes.DebuggerHiddenAttribute
             GenerateMoveNext(Me.StartMethodImplementation(
                     WellKnownMember.System_Runtime_CompilerServices_IAsyncStateMachine_MoveNext,
                     "MoveNext",
-                    DebugAttributes.CompilerGeneratedAttribute, Accessibility.Friend, True, asyncKickoffMethod:=Me.Method))
+                    moveNextAttrs, Accessibility.Friend, True, asyncKickoffMethod:=Me.Method))
 
             'Add IAsyncStateMachine.SetStateMachine()
             Me.StartMethodImplementation(

Src/Compilers/VisualBasic/Portable/Lowering/IteratorRewriter/IteratorRewriter.vb

@@ -144,9 +144,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                                                              Accessibility.Private,
                                                              False)
 
+            Dim debuggerHidden = IsDebuggerHidden(Me.Method)
+            Dim moveNextAttrs As DebugAttributes = DebugAttributes.CompilerGeneratedAttribute
+            If debuggerHidden Then moveNextAttrs = moveNextAttrs Or DebugAttributes.DebuggerHiddenAttribute
             Dim moveNextMethod = Me.StartMethodImplementation(SpecialMember.System_Collections_IEnumerator__MoveNext,
                                                              "MoveNext",
-                                                             DebugAttributes.CompilerGeneratedAttribute,
+                                                             moveNextAttrs,
                                                              Accessibility.Private,
                                                              True)
 

Src/Compilers/VisualBasic/Portable/Lowering/StateMachineRewriter/StateMachineRewriter.vb

@@ -435,6 +435,14 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             Return body
         End Function
 
+        Protected Function IsDebuggerHidden(method As MethodSymbol) As Boolean
+            Dim debuggerHiddenAttribute = Me.CompilationState.Compilation.GetWellKnownType(WellKnownType.System_Diagnostics_DebuggerHiddenAttribute)
+            For Each a In Me.Method.GetAttributes()
+                If a.AttributeClass = debuggerHiddenAttribute Then Return True
+            Next
+
+            Return False
+        End Function
     End Class
 
 End Namespace

Src/Compilers/VisualBasic/Test/Emit/PDB/PDBIteratorTests.vb

@@ -410,5 +410,69 @@ End Class
             PDBTests.AssertXmlEqual(expected, actual)
         End Sub
 
+        <Fact, WorkItem(667579, "DevDiv")>
+        Public Sub DebuggerHiddenIterator()
+            Dim source =
+<compilation>
+    <file>
+Imports System
+Imports System.Collections.Generic
+Imports System.Diagnostics
+Module Module1
+
+    Sub Main()
+        For Each i In Foo
+            Console.Write(i)
+        Next
+    End Sub
+
+    &lt;DebuggerHidden&gt;
+    Iterator Function Foo() As IEnumerable(Of Integer)
+        Yield 1
+        Yield 2
+    End Function
+
+End Module
+    </file>
+</compilation>
+
+            Dim compilation = CompilationUtils.CreateCompilationWithMscorlibAndVBRuntime(
+                    source,
+                    OptionsExe.WithOptimizations(False))
+
+            Dim actual = PDBTests.GetPdbXml(compilation, "Module1+VB$StateMachine_1_Foo.MoveNext")
+
+            Dim expected =
+<symbols>
+    <entryPoint declaringType="Module1" methodName="Main" parameterNames=""/>
+    <methods>
+        <method containingType="Module1+VB$StateMachine_1_Foo" name="MoveNext" parameterNames="">
+            <sequencepoints total="6">
+                <entry il_offset="0x0" hidden="true" start_row="16707566" start_column="0" end_row="16707566" end_column="0" file_ref="0"/>
+                <entry il_offset="0x2c" start_row="12" start_column="5" end_row="13" end_column="55" file_ref="0"/>
+                <entry il_offset="0x2d" start_row="13" start_column="5" end_row="13" end_column="55" file_ref="0"/>
+                <entry il_offset="0x2e" start_row="14" start_column="9" end_row="14" end_column="16" file_ref="0"/>
+                <entry il_offset="0x49" start_row="15" start_column="9" end_row="15" end_column="16" file_ref="0"/>
+                <entry il_offset="0x64" start_row="16" start_column="5" end_row="16" end_column="17" file_ref="0"/>
+            </sequencepoints>
+            <locals>
+                <local name="VB$returnTemp" il_index="0" il_start="0x0" il_end="0x66" attributes="1"/>
+                <local name="VB$cachedState" il_index="1" il_start="0x0" il_end="0x66" attributes="1"/>
+                <local name="MoveNext" il_index="2" il_start="0x2d" il_end="0x65" attributes="0"/>
+            </locals>
+            <scope startOffset="0x0" endOffset="0x66">
+                <importsforward declaringType="Module1" methodName="Main" parameterNames=""/>
+                <local name="VB$returnTemp" il_index="0" il_start="0x0" il_end="0x66" attributes="1"/>
+                <local name="VB$cachedState" il_index="1" il_start="0x0" il_end="0x66" attributes="1"/>
+                <scope startOffset="0x2d" endOffset="0x65">
+                    <local name="MoveNext" il_index="2" il_start="0x2d" il_end="0x65" attributes="0"/>
+                </scope>
+            </scope>
+        </method>
+    </methods>
+</symbols>
+            PDBTests.AssertXmlEqual(expected, actual)
+        End Sub
+
     End Class
 End Namespace