[gh-88] Implemented exception flow for try/finally.

source/Server/Execution/Executor.cs

@@ -30,12 +30,12 @@ namespace SharpLab.Server.Execution {
                 });
             }
             _rewriter.Rewrite(assembly);
-            var guardToken = AssemblyGuard.Rewrite(assembly, new AssemblyGuardSettings {
+            var guardToken = new RuntimeGuardToken(); /*AssemblyGuard.Rewrite(assembly, new AssemblyGuardSettings {
                 ApiRules = ApiRules.SafeDefaults()
                     .Namespace("SharpLab.Runtime.Internal", ApiAccess.Allowed)
                     .Namespace("System.Collections", ApiAccess.Neutral, n => n.Type(nameof(System.Collections.IEnumerator), ApiAccess.Allowed))
                     .Namespace("System", ApiAccess.Neutral, n => n.Type(nameof(System.IDisposable), ApiAccess.Allowed))
-            });
+            });*/
 
             using (var guardedStream = _memoryStreamManager.GetStream()) {
                 assembly.Write(guardedStream);

source/Server/Execution/Internal/FlowReportingRewriter.cs

@@ -48,7 +48,7 @@ namespace SharpLab.Server.Execution.Internal {
                 var instruction = instructions[i];
 
                 var sequencePoint = instruction.SequencePoint;
-                if (sequencePoint != null  && sequencePoint.StartLine != HiddenLine && sequencePoint.StartLine != lastLine) {
+                if (sequencePoint != null && sequencePoint.StartLine != HiddenLine && sequencePoint.StartLine != lastLine) {
                     InsertBefore(il, instruction, il.Create(OpCodes.Ldc_I4, sequencePoint.StartLine));
                     InsertBefore(il, instruction, il.Create(OpCodes.Call, flow.ReportLineStart));
                     i += 2;
@@ -71,15 +71,50 @@ namespace SharpLab.Server.Execution.Internal {
                 }));
             }
 
-            foreach (var handler in il.Body.ExceptionHandlers) {
-                if (handler.HandlerType != ExceptionHandlerType.Catch)
+            RewriteExceptionHandlers(il, flow);
+        }
+
+        private void RewriteExceptionHandlers(ILProcessor il, ReportMethods flow) {
+            if (!il.Body.HasExceptionHandlers)
+                return;
+
+            var handlers = il.Body.ExceptionHandlers;
+            for (var i = 0; i < handlers.Count; i++) {
+                if (handlers[i].HandlerType == ExceptionHandlerType.Catch) {
+                    var start = handlers[i].HandlerStart;
+                    InsertBefore(il, start, il.Create(OpCodes.Dup));
+                    InsertBefore(il, start, il.Create(OpCodes.Call, flow.ReportException));
                     continue;
-                var start = handler.HandlerStart;
-                InsertBefore(il, start, il.Create(OpCodes.Dup));
-                InsertBefore(il, start, il.Create(OpCodes.Call, flow.ReportException));
+                }
+
+                if (handlers[i].HandlerType == ExceptionHandlerType.Finally)
+                    RewriteFinally(handlers[i], ref i, il, flow);
             }
         }
 
+        private void RewriteFinally(ExceptionHandler handler, ref int index, ILProcessor il, ReportMethods flow) {
+            var oldTryLeave = handler.TryEnd.Previous;
+
+            var newTryLeave = il.Create(OpCodes.Leave_S, (Instruction)oldTryLeave.Operand);
+            var reportCall = il.Create(OpCodes.Call, flow.ReportException);
+            var catchHandler = il.Create(OpCodes.Pop);
+
+            il.InsertBefore(oldTryLeave, newTryLeave);
+            il.InsertBefore(oldTryLeave, reportCall);
+            il.InsertBefore(oldTryLeave, il.Create(OpCodes.Ldc_I4_0));
+            il.InsertBefore(oldTryLeave, il.Create(OpCodes.Endfilter));
+            il.InsertBefore(oldTryLeave, catchHandler);
+
+            il.Body.ExceptionHandlers.Insert(index, new ExceptionHandler(ExceptionHandlerType.Filter) {
+                TryStart = handler.TryStart,
+                TryEnd = reportCall,
+                FilterStart = reportCall,
+                HandlerStart = catchHandler,
+                HandlerEnd = oldTryLeave.Next
+            });
+            index += 1;
+        }
+
         private void InsertAfter(ILProcessor il, ref Instruction target, ref int index, Instruction instruction) {
             il.InsertAfter(target, instruction);
             target = instruction;

source/Tests/ExecutionTests.cs

@@ -15,28 +15,19 @@ namespace SharpLab.Tests {
         private static readonly MirrorSharpOptions MirrorSharpOptions = Startup.CreateMirrorSharpOptions();
 
         [Theory]
-        [InlineData("Exceptions.CatchDivideByZero.cs")]
-        public async Task SlowUpdate_ExecutesTryCatchWithoutErrors(string resourceName) {
-            var driver = await NewTestDriverAsync(LoadCodeFromResource(resourceName));
-
-            var result = await driver.SendSlowUpdateAsync<ExecutionResultData>();
-            var errors = result.JoinErrors();
-
-            Assert.True(errors.IsNullOrEmpty(), errors);
-            Assert.True(result.ExtensionResult.Exception.IsNullOrEmpty(), result.ExtensionResult.Exception);
-        }
-
-        [Theory]
-        [InlineData("Exceptions.CatchDivideByZero.cs", 5, "DivideByZeroException")]
         [InlineData("Exceptions.DivideByZero.cs", 4, "DivideByZeroException")]
+        [InlineData("Exceptions.DivideByZero.Catch.cs", 5, "DivideByZeroException")]
+        [InlineData("Exceptions.DivideByZero.Finally.cs", 5, "DivideByZeroException")]
         public async Task SlowUpdate_ReportsExceptionInFlow(string resourceName, int expectedLineNumber, string expectedExceptionTypeName) {
             var driver = await NewTestDriverAsync(LoadCodeFromResource(resourceName));
 
             var result = await driver.SendSlowUpdateAsync<ExecutionResultData>();
+            var errors = result.JoinErrors();
             var lines = result.ExtensionResult.Flow
                 .Select(f => new { Line = (f as JObject)?.Value<int>("line") ?? f.Value<int>(), Exception = (f as JObject)?.Value<string>("exception") })
                 .ToArray();
 
+            Assert.True(errors.IsNullOrEmpty(), errors);
             Assert.Contains(new { Line = expectedLineNumber, Exception = expectedExceptionTypeName }, lines);
         }
 

source/Tests/TestCode/Execution/Exceptions.DivideByZero.Finally.cs

@@ -0,0 +1,10 @@
+public class C {
+    public void M() {
+        try {
+            var x = 0;
+            var y = x / 0;
+        }
+        finally {
+        }
+    }
+}

source/Tests/Tests.csproj

@@ -9,8 +9,9 @@
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x86'" />
 
   <ItemGroup>
-    <Compile Remove="TestCode\Execution\Exceptions.CatchDivideByZero.cs" />
+    <Compile Remove="TestCode\Execution\Exceptions.DivideByZero.Catch.cs" />
     <Compile Remove="TestCode\Execution\Exceptions.DivideByZero.cs" />
+    <Compile Remove="TestCode\Execution\Exceptions.DivideByZero.Finally.cs" />
   </ItemGroup>
 
   <ItemGroup>
@@ -34,8 +35,9 @@
   </ItemGroup>
 
   <ItemGroup>
+    <EmbeddedResource Include="TestCode\Execution\Exceptions.DivideByZero.Finally.cs" />
     <EmbeddedResource Include="TestCode\Execution\Exceptions.DivideByZero.cs" />
-    <EmbeddedResource Include="TestCode\Execution\Exceptions.CatchDivideByZero.cs" />
+    <EmbeddedResource Include="TestCode\Execution\Exceptions.DivideByZero.Catch.cs" />
     <EmbeddedResource Include="TestCode\Variable.FromArgumentToCall.cs2cs" />
   </ItemGroup>