Runtime: Add WASI Preview 1 proc_exit function

This function will normally call Environment.Exit(code), but an
integration point was added to WasmRuntime in order to facilitate unit
testing (or allow a user of the runtime to choose to do something else
upon this call).

WasmNet.Core/HostFunctionInstance.cs

@@ -1,16 +1,10 @@
 namespace WasmNet.Core;
 
-public class HostFunctionInstance : IFunctionInstance
+public class HostFunctionInstance(WasmType type, Delegate hostCode) : IFunctionInstance
 {
-    public HostFunctionInstance(WasmType type, Delegate hostCode)
-    {
-        Type = type;
-        HostCode = hostCode;
-    }
+    public WasmType Type { get; } = type;
 
-    public WasmType Type { get; }
-
-    public Delegate HostCode { get; }
+    public Delegate HostCode { get; } = hostCode;
 
     public Type ReturnType => HostCode.Method.ReturnType;
 

WasmNet.Core/Wasi/Preview1.ProcExit.cs

@@ -0,0 +1,6 @@
+namespace WasmNet.Core.Wasi;
+
+public static partial class Preview1
+{
+    public static void ProcExit(WasmRuntime runtime, int exitCode) => runtime.ExitHandler(exitCode);
+}

WasmNet.Core/Wasi/Preview1.cs

@@ -0,0 +1,20 @@
+namespace WasmNet.Core.Wasi;
+
+public static partial class Preview1
+{
+    public const string Namespace = "wasi_snapshot_preview1";
+
+    public static void RegisterWasiPreview1(this WasmRuntime runtime)
+    {
+        var actionIntType = new WasmType
+        {
+            Kind = WasmTypeKind.Function,
+            Parameters = new List<WasmValueType>
+            {
+                WasmNumberType.I32
+            }
+        };
+
+        runtime.RegisterImportable(Namespace, "proc_exit", (int exitCode) => ProcExit(runtime, exitCode));
+    }
+}

WasmNet.Core/WasmRuntime.cs

@@ -1,14 +1,22 @@
 using System.Reflection;
 using System.Reflection.Emit;
+using WasmNet.Core.Wasi;
 
 namespace WasmNet.Core;
 
 public class WasmRuntime
 {
-    public Store Store { get; } = new();
-
     private readonly IDictionary<string, IDictionary<string, object?>> _importables = new Dictionary<string, IDictionary<string, object?>>();
 
+    public WasmRuntime()
+    {
+        this.RegisterWasiPreview1();
+    }
+
+    public Action<int> ExitHandler { get; set; } = Environment.Exit;
+
+    public Store Store { get; } = new();
+
     public void RegisterImportable(string module, string name, object? value)
     {
         if (!_importables.TryGetValue(module, out var importables))

WasmNet.Tests/IntegrationTests.cs

@@ -22,7 +22,10 @@ public async Task IntegrationTest(string file)
             throw new Exception($"wat2wasm failed to produce {wasmFile}.");
         }
 
-        WasmRuntime runtime = new();
+        WasmRuntime runtime = new()
+        {
+            ExitHandler = code => throw new ExitCodeException(code),
+        };
 
         var externalCalls = new Dictionary<string, int>();
 
@@ -128,7 +131,7 @@ public async Task IntegrationTest(string file)
             }
             else if (op is ExpectTrapOperation expectTrap)
             {
-                if (exception is TargetInvocationException tie)
+                while (exception is TargetInvocationException tie)
                 {
                     exception = tie.InnerException;
                 }
@@ -137,6 +140,21 @@ public async Task IntegrationTest(string file)
                 Assert.Equal(expectTrap.ExceptionType, exception.GetType().Name);
                 testOutputHelper.WriteLine($"Exception is of type {exception.GetType().Name}: {exception.Message}");
             }
+            else if (op is ExitCodeOperation exitCode)
+            {
+                while (exception is TargetInvocationException tie)
+                {
+                    exception = tie.InnerException;
+                }
+
+                if (exception is not ExitCodeException ece)
+                {
+                    throw new Exception($"Expected exit code {exitCode.ExitCode} but the program did not exit");
+                }
+
+                Assert.Equal(exitCode.ExitCode, ece.ExitCode);
+                testOutputHelper.WriteLine($"Expected exit code {exitCode.ExitCode} and got {ece.ExitCode}");
+            }
             else
             {
                 throw new NotImplementedException($"Unknown operation: {op.GetType().Name}");
@@ -150,9 +168,34 @@ public static IEnumerable<object[]> GetWatFiles()
 
         return files.Select(i => new object[] { Path.GetFileName(i) });
     }
+
+    private class ExitCodeException : Exception
+    {
+        public ExitCodeException(int exitCode)
+        {
+            ExitCode = exitCode;
+        }
+
+        public int ExitCode { get; }
+    }
 
     private abstract class Operation;
 
+    private class ExitCodeOperation : Operation
+    {
+        public required int ExitCode { get; init; }
+
+        public static ExitCodeOperation Parse(string text)
+        {
+            var code = int.Parse(text);
+
+            return new ExitCodeOperation
+            {
+                ExitCode = code,
+            };
+        }
+    }
+
     private class ExpectTrapOperation : Operation
     {
         public required string ExceptionType { get; init; }
@@ -348,6 +391,10 @@ public static Header Parse(string text)
                 {
                     ops.Add(ExpectTrapOperation.Parse(line[13..]));
                 }
+                else if (line.StartsWith("exit_code: "))
+                {
+                    ops.Add(ExitCodeOperation.Parse(line[11..]));
+                }
                 else if (line.StartsWith("source: ") || line.StartsWith("TODO: ") || line.StartsWith("NOTE:"))
                 {
                     // ignore

WasmNet.Tests/IntegrationTests/0150-WasiPreview1ProcExit.wat

@@ -0,0 +1,12 @@
+;; invoke: proc-exit
+;; exit_code: 1
+
+(module
+    (type $t0 (func (param i32)))
+    (import "wasi_snapshot_preview1" "proc_exit" (func $exit (type $t0)))
+    (func (export "proc-exit")
+        (call $exit (i32.const 1))
+    )
+    (memory (;0;) 256 256)
+    (export "memory" (memory 0))
+)

WasmNet.sln.DotSettings

@@ -1,3 +1,4 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=importables/@EntryIndexedValue">True</s:Boolean>
-	<s:Boolean x:Key="/Default/UserDictionary/Words/=logmem/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=logmem/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=Wasi/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>