Add retargeting switch labels to ILProcessor (#2801)

Fixes #2799

2 files changed, 82 insertions, 0 deletions

diff --git a/test/Mono.Linker.Tests.Cases/UnreachableBlock/ReplacedJumpTarget.cs b/test/Mono.Linker.Tests.Cases/UnreachableBlock/ReplacedJumpTarget.cs
new file mode 100644
index 000000000..5c7ee375f
--- /dev/null
+++ b/test/Mono.Linker.Tests.Cases/UnreachableBlock/ReplacedJumpTarget.cs
@@ -0,0 +1,77 @@
+using System;
+using System.Reflection.Emit;
+using Mono.Linker.Tests.Cases.Expectations.Assertions;
+using Mono.Linker.Tests.Cases.Expectations.Metadata;
+
+namespace Mono.Linker.Tests.Cases.UnreachableBlock
+{
+	[SetupCompileArgument ("/optimize+")]
+	[SetupLinkerArgument ("--enable-opt", "ipconstprop")]
+	public class ReplacedJumpTarget
+	{
+		public static void Main ()
+		{
+			Test_1 (int.Parse ("91"));
+		}
+
+		[Kept]
+		[ExpectedInstructionSequence (new[] {
+			"ldarg.0",
+			"ldc.i4.2",
+			"sub",
+			"switch (il_2a, il_2c, il_2e, il_30, il_32)",
+			"ldarg.0",
+			"ldc.i4.s 0x32",
+			"sub",
+			"ldc.i4.5",
+			"ble.un.s il_34",
+			"ldarg.0",
+			"ldc.i4.s 0x64",
+			"bne.un.s il_36",
+			"ldc.i4.1",
+			"ret",
+			"ldc.i4.2",
+			"ret",
+			"ldc.i4.2",
+			"ret",
+			"ldc.i4.2",
+			"ret",
+			"ldc.i4.5",
+			"ret",
+			"ldc.i4.5",
+			"ret",
+			"ldc.i4.5",
+			"ret",
+			"ldc.i4.2",
+			"ret",
+			})]
+		static int Test_1 (int value)
+		{
+			switch (value) {
+			case 100:
+				return 1;
+			case 2:
+				return Value;
+			case 3:
+				return Value;
+			case 4:
+				return Value;
+			case 5:
+				return 5;
+			case 6:
+				return 5;
+			case 50:
+			case 51:
+			case 52:
+			case 53:
+			case 54:
+			case 55:
+				return 5;
+			}
+
+			return 2;
+		}
+
+		static int Value => 2;
+	}
+}
\ No newline at end of file
diff --git a/test/Mono.Linker.Tests/TestCasesRunner/AssemblyChecker.cs b/test/Mono.Linker.Tests/TestCasesRunner/AssemblyChecker.cs
index e6a9a6012..630dfef12 100644
--- a/test/Mono.Linker.Tests/TestCasesRunner/AssemblyChecker.cs
+++ b/test/Mono.Linker.Tests/TestCasesRunner/AssemblyChecker.cs
@@ -490,6 +490,11 @@ namespace Mono.Linker.Tests.TestCasesRunner
 				if (instr.Operand is Instruction target)
 					return $"{instr.OpCode.ToString ()} il_{target.Offset.ToString ("x")}";
 
+				if (instr.Operand is Instruction[] targets) {
+					string stargets = string.Join (", ", targets.Select (l => $"il_{l.Offset.ToString ("x")}"));
+					return $"{instr.OpCode.ToString ()} ({stargets})";
+				}
+
 				break;
 			}