Merge pull request #48066 from 333fred/func-ptr-in-ref

Rewrite function pointer arguments during local rewrite

src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_FunctionPointerInvocation.cs

@@ -0,0 +1,43 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#nullable enable
+
+using System.Collections.Immutable;
+using Microsoft.CodeAnalysis.CSharp.Symbols;
+
+namespace Microsoft.CodeAnalysis.CSharp
+{
+    internal sealed partial class LocalRewriter
+    {
+        public override BoundNode? VisitFunctionPointerInvocation(BoundFunctionPointerInvocation node)
+        {
+            var rewrittenExpression = VisitExpression(node.InvokedExpression);
+            var rewrittenArgs = VisitList(node.Arguments);
+
+            MethodSymbol functionPointer = node.FunctionPointer.Signature;
+            var argumentRefKindsOpt = node.ArgumentRefKindsOpt;
+            rewrittenArgs = MakeArguments(
+                node.Syntax,
+                rewrittenArgs,
+                functionPointer,
+                functionPointer,
+                expanded: false,
+                argsToParamsOpt: default,
+                ref argumentRefKindsOpt,
+                out ImmutableArray<LocalSymbol> temps,
+                invokedAsExtensionMethod: false,
+                enableCallerInfo: ThreeState.False);
+
+            node = node.Update(rewrittenExpression, rewrittenArgs, argumentRefKindsOpt, node.ResultKind, node.Type);
+
+            if (temps.IsDefaultOrEmpty)
+            {
+                return node;
+            }
+
+            return new BoundSequence(node.Syntax, temps, sideEffects: ImmutableArray<BoundExpression>.Empty, node, node.Type);
+        }
+    }
+}

src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenFunctionPointersTests.cs

@@ -10778,6 +10778,96 @@ public static void M2()
             Assert.Equal(ConversionKind.AnonymousFunction, conversion.Kind);
         }
 
+        [Fact, WorkItem(47487, "https://github.com/dotnet/roslyn/issues/47487")]
+        public void InAndRefParameter()
+        {
+            var verifier = CompileAndVerifyFunctionPointers(@"
+using System;
+unsafe
+{
+    delegate*<in int, ref char, void> F = &Test;
+    char c = 'a';
+    F(int.MaxValue, ref c);
+}
+
+static void Test(in int b, ref char c)
+{
+    Console.WriteLine($""b = {b}, c = {c}"");
+}
+", expectedOutput: "b = 2147483647, c = a");
+
+            verifier.VerifyIL("<top-level-statements-entry-point>", @"
+{
+  // Code size       27 (0x1b)
+  .maxstack  3
+  .locals init (char V_0, //c
+                delegate*<in int, ref char, void> V_1,
+                int V_2)
+  IL_0000:  ldftn      ""void <Program>$.<<Main>$>g__Test|0_0(in int, ref char)""
+  IL_0006:  ldc.i4.s   97
+  IL_0008:  stloc.0
+  IL_0009:  stloc.1
+  IL_000a:  ldc.i4     0x7fffffff
+  IL_000f:  stloc.2
+  IL_0010:  ldloca.s   V_2
+  IL_0012:  ldloca.s   V_0
+  IL_0014:  ldloc.1
+  IL_0015:  calli      ""delegate*<in int, ref char, void>""
+  IL_001a:  ret
+}
+");
+        }
+
+        [Fact, WorkItem(47487, "https://github.com/dotnet/roslyn/issues/47487")]
+        public void OutDiscard()
+        {
+            var verifier = CompileAndVerifyFunctionPointers(@"
+using System;
+unsafe
+{
+    delegate*<out int, out int, void> F = &Test;
+    F(out var i1, out _);
+    F(out _, out var i2);
+    Console.Write(i1);
+    Console.Write(i2);
+}
+
+static void Test(out int i1, out int i2)
+{
+    i1 = 1;
+    i2 = 2;
+}
+", expectedOutput: "12");
+
+            verifier.VerifyIL("<top-level-statements-entry-point>", @"
+{
+  // Code size       42 (0x2a)
+  .maxstack  4
+  .locals init (int V_0, //i1
+                int V_1, //i2
+                int V_2,
+                delegate*<out int, out int, void> V_3)
+  IL_0000:  ldftn      ""void <Program>$.<<Main>$>g__Test|0_0(out int, out int)""
+  IL_0006:  dup
+  IL_0007:  stloc.3
+  IL_0008:  ldloca.s   V_0
+  IL_000a:  ldloca.s   V_2
+  IL_000c:  ldloc.3
+  IL_000d:  calli      ""delegate*<out int, out int, void>""
+  IL_0012:  stloc.3
+  IL_0013:  ldloca.s   V_2
+  IL_0015:  ldloca.s   V_1
+  IL_0017:  ldloc.3
+  IL_0018:  calli      ""delegate*<out int, out int, void>""
+  IL_001d:  ldloc.0
+  IL_001e:  call       ""void System.Console.Write(int)""
+  IL_0023:  ldloc.1
+  IL_0024:  call       ""void System.Console.Write(int)""
+  IL_0029:  ret
+}
+");
+        }
+
         private static readonly Guid s_guid = new Guid("97F4DBD4-F6D1-4FAD-91B3-1001F92068E5");
         private static readonly BlobContentId s_contentId = new BlobContentId(s_guid, 0x04030201);