Fix NativeAOT unhandled exception stack trace

src/coreclr/nativeaot/Runtime.Base/src/System/Runtime/ExceptionHandling.cs

@@ -708,14 +708,14 @@ private static void DispatchEx(scoped ref StackFrameIterator frameIter, ref ExIn
             uint startIdx = MaxTryRegionIdx;
             for (; isValid; isValid = frameIter.Next(&startIdx, &unwoundReversePInvoke))
             {
-                prevControlPC = frameIter.ControlPC;
-                prevOriginalPC = frameIter.OriginalControlPC;
-
                 // For GC stackwalking, we'll happily walk across native code blocks, but for EH dispatch, we
                 // disallow dispatching exceptions across native code.
                 if (unwoundReversePInvoke)
                     break;
 
+                prevControlPC = frameIter.ControlPC;
+                prevOriginalPC = frameIter.OriginalControlPC;
+
                 DebugScanCallFrame(exInfo._passNumber, frameIter.ControlPC, frameIter.SP);
 
                 UpdateStackTrace(exceptionObj, exInfo._frameIter.FramePointer, (IntPtr)frameIter.OriginalControlPC, frameIter.SP, ref isFirstRethrowFrame, ref prevFramePtr, ref isFirstFrame, ref exInfo);

src/coreclr/nativeaot/System.Private.CoreLib/src/System/RuntimeExceptionHelpers.cs

@@ -221,7 +221,7 @@ internal static unsafe void FailFast(string? message, Exception? exception, RhFa
                     string outputMessage;
                     if (exception != null)
                     {
-                        prefix = "Unhandled Exception: ";
+                        prefix = "Unhandled exception. ";
                         outputMessage = exception.ToString();
                     }
                     else

src/tests/baseservices/exceptions/unhandled/unhandled.cs

@@ -0,0 +1,101 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.Text;
+using System.Text.RegularExpressions;
+
+namespace TestUnhandledException
+{
+    class Program
+    {
+        static int Main(string[] args)
+        {
+            if (args.Length != 0)
+            {
+                throw new Exception("Test");
+            }
+
+            List<string> lines = new List<string>();
+
+            Process testProcess = new Process();
+
+            testProcess.StartInfo.FileName = Environment.ProcessPath;
+            testProcess.StartInfo.Arguments = Environment.CommandLine + " throw";
+            testProcess.StartInfo.RedirectStandardError = true;
+            testProcess.ErrorDataReceived += (sender, line) => 
+            {
+                Console.WriteLine($"\"{line.Data}\"");
+                if (!string.IsNullOrEmpty(line.Data))
+                {
+                    lines.Add(line.Data);
+                }
+            };
+
+            testProcess.Start();
+            testProcess.BeginErrorReadLine();
+            testProcess.WaitForExit();
+            testProcess.CancelErrorRead();
+
+            int expectedExitCode;
+            if (TestLibrary.Utilities.IsMonoRuntime)
+            {
+                expectedExitCode = 1;
+            }
+            else if (!OperatingSystem.IsWindows())
+            {
+                expectedExitCode = 128 + 6;
+            }
+            else if (TestLibrary.Utilities.IsNativeAot)
+            {
+                expectedExitCode = unchecked((int)0xC0000409);
+            }
+            else
+            {
+                expectedExitCode = unchecked((int)0xE0434352);
+            }
+
+            if (expectedExitCode != testProcess.ExitCode)
+            {
+                Console.WriteLine($"Wrong exit code 0x{testProcess.ExitCode:X8}");
+                return 101;
+            }
+
+            int exceptionStackFrameLine = 1;
+            if (TestLibrary.Utilities.IsMonoRuntime)
+            {
+                if (lines[0] != "Unhandled Exception:")
+                {
+                    Console.WriteLine("Missing Unhandled exception header");
+                    return 102;
+                }
+                if (lines[1] != "System.Exception: Test")
+                {
+                    Console.WriteLine("Missing exception type and message");
+                    return 103;
+                }
+
+                exceptionStackFrameLine = 2;
+            }
+            else
+            {
+                if (lines[0] != "Unhandled exception. System.Exception: Test")
+                {
+                    Console.WriteLine("Missing Unhandled exception header");
+                    return 102;
+                }
+
+            }
+
+            if (!lines[exceptionStackFrameLine].TrimStart().StartsWith("at TestUnhandledException.Program.Main"))
+            {
+                Console.WriteLine("Missing exception source frame");
+                return 103;
+            }
+
+            return 100;
+        }
+    }
+}

src/tests/baseservices/exceptions/unhandled/unhandled.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <Optimize>false</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="unhandled.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="$(TestSourceDir)Common/CoreCLRTestLibrary/CoreCLRTestLibrary.csproj" />
+  </ItemGroup>
+</Project>

src/tests/issues.targets

@@ -3230,6 +3230,9 @@
     </ItemGroup>
 
     <ItemGroup Condition="'$(TargetArchitecture)' == 'wasm'">
+        <ExcludeList Include = "$(XunitTestBinBase)/baseservices/exceptions/unhandled/unhandled/**">
+            <Issue>System.Diagnostics.Process is not supported</Issue>
+        </ExcludeList>
         <ExcludeList Include = "$(XunitTestBinBase)/tracing/eventcounter/incrementingeventcounter/**">
             <Issue>System.Threading.Thread.UnsafeStart not supported</Issue>
         </ExcludeList>