Revert "#1083: Add ArgumentToParameterMap to CallInstruction, in ILAst output call arguments are now prefixed with the parameter index they correspond to, if the mapping is different from the default."

This reverts commit 60ace84f26.

ICSharpCode.Decompiler/IL/Instructions/CallInstruction.cs

@@ -18,10 +18,8 @@
 
 using System;
 using System.Diagnostics;
-using System.Linq;
 using ICSharpCode.Decompiler.Disassembler;
 using ICSharpCode.Decompiler.TypeSystem;
-using ICSharpCode.Decompiler.Util;
 
 namespace ICSharpCode.Decompiler.IL
 {
@@ -60,21 +58,10 @@ namespace ICSharpCode.Decompiler.IL
 		/// </summary>
 		public bool ILStackWasEmpty;
 
-		/// <summary>
-		/// Gets the mapping of arguments to method parameters. Must be a 1-to-1 mapping.
-		/// Normally this is index == value for static calls and newobj, and value + 1 == index for instance method calls.
-		/// |ArgumentToParameterMap|  == |Arguments|.
-		/// </summary>
-		public int[] ArgumentToParameterMap;
-
 		protected CallInstruction(OpCode opCode, IMethod method) : base(opCode)
 		{
 			Debug.Assert(method != null);
 			this.Method = method;
-			int firstParameter = OpCode != OpCode.NewObj && !Method.IsStatic ? 1 : 0;
-			this.ArgumentToParameterMap = new int[method.Parameters.Count + firstParameter];
-			for (int i = 0; i < ArgumentToParameterMap.Length; i++)
-				ArgumentToParameterMap[i] = -firstParameter + i;
 			this.Arguments = new InstructionCollection<ILInstruction>(this, 0);
 		}
 
@@ -126,24 +113,13 @@ namespace ICSharpCode.Decompiler.IL
 			base.CheckInvariant(phase);
 			int firstArgument = (OpCode != OpCode.NewObj && !Method.IsStatic) ? 1 : 0;
 			Debug.Assert(Method.Parameters.Count + firstArgument == Arguments.Count);
-			Debug.Assert(Method.Parameters.Count + firstArgument == ArgumentToParameterMap.Length);
 			if (firstArgument == 1) {
 				Debug.Assert(Arguments[0].ResultType == ExpectedTypeForThisPointer(ConstrainedTo ?? Method.DeclaringType),
 					$"Stack type mismatch in 'this' argument in call to {Method.Name}()");
-				Debug.Assert(ArgumentToParameterMap[0] == -1, "'this' argument must always be mapped at position 0");
 			}
-			int paramCount = Method.Parameters.Count;
-			if (paramCount > 0) {
-				BitSet bitSet = new BitSet(paramCount);
-				for (int i = 0; i < paramCount; ++i) {
-					int mappedTo = ArgumentToParameterMap[firstArgument + i];
-					Debug.Assert(mappedTo >= 0 && mappedTo < paramCount, $"mapping out of [0..{paramCount}[, was: {mappedTo}");
-					Debug.Assert(!bitSet[mappedTo], $"argument {mappedTo} is already mapped to a different parameter");
-					bitSet.Set(mappedTo);
-					Debug.Assert(Arguments[firstArgument + i].ResultType == Method.Parameters[mappedTo].Type.GetStackType(),
-						$"Stack type mismatch in parameter {mappedTo} (argument {firstArgument + i}) in call to {Method.Name}()");
-				}
-				Debug.Assert(bitSet.All(0, paramCount - 1), "Not all arguments are mapped to a parameter");
+			for (int i = 0; i < Method.Parameters.Count; ++i) {
+				Debug.Assert(Arguments[firstArgument + i].ResultType == Method.Parameters[i].Type.GetStackType(),
+					$"Stack type mismatch in parameter {i} in call to {Method.Name}()");
 			}
 		}
 
@@ -161,12 +137,9 @@ namespace ICSharpCode.Decompiler.IL
 			output.Write(' ');
 			Method.WriteTo(output);
 			output.Write('(');
-			int firstIndex = (OpCode != OpCode.NewObj && !Method.IsStatic) ? -1 : 0;
 			for (int i = 0; i < Arguments.Count; i++) {
 				if (i > 0)
 					output.Write(", ");
-				if (ArgumentToParameterMap[i] != firstIndex + i)
-					output.Write($"{ArgumentToParameterMap[i]}: ");
 				Arguments[i].WriteTo(output, options);
 			}
 			output.Write(')');
@@ -177,8 +150,7 @@ namespace ICSharpCode.Decompiler.IL
 			CallInstruction o = other as CallInstruction;
 			return o != null && this.OpCode == o.OpCode && this.Method.Equals(o.Method) && this.IsTail == o.IsTail
 				&& object.Equals(this.ConstrainedTo, o.ConstrainedTo)
-				&& Patterns.ListMatch.DoMatch(this.Arguments, o.Arguments, ref match)
-				&& ArgumentToParameterMap.SequenceEqual(o.ArgumentToParameterMap);
+				&& Patterns.ListMatch.DoMatch(this.Arguments, o.Arguments, ref match);
 		}
 	}