Upstream icsharpcode/ILSpy state of the touched files before bf9e4c8951

ICSharpCode.Decompiler.Tests/TestCases/Pretty/TypeAnalysisTests.cs

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+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Reflection;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
+{
+	public class TypeAnalysisTests
+	{
+		private class @_
+		{
+		}
+
+		private byte[] byteArray;
+		private ulong uint64Field;
+
+		public int Issue1796a {
+			get {
+				return (int)(uint64Field & 0x7FFFFFFF);
+			}
+			set {
+				uint64Field = (uint64Field & 0xFFFFFFFF80000000uL) | (ulong)value;
+			}
+		}
+
+		public ushort Issue1796b {
+			get {
+				return (ushort)((uint64Field & 0xFFFF000000000000uL) >> 48);
+			}
+			set {
+				uint64Field = (uint64Field & 0xFFFFFFFFFFFFL) | ((ulong)value << 48);
+			}
+		}
+
+		public byte SubtractFrom256(byte b)
+		{
+			return (byte)(256 - b);
+		}
+
+		#region Shift
+		public int LShiftInteger(int num1, int num2)
+		{
+			return num1 << num2;
+		}
+
+		public uint LShiftUnsignedInteger(uint num1, uint num2)
+		{
+			return num1 << (int)num2;
+		}
+
+		public long LShiftLong(long num1, long num2)
+		{
+			return num1 << (int)num2;
+		}
+
+		public ulong LShiftUnsignedLong(ulong num1, ulong num2)
+		{
+			return num1 << (int)num2;
+		}
+
+		public int RShiftInteger(int num1, int num2)
+		{
+			return num1 >> num2;
+		}
+
+		public uint RShiftUnsignedInteger(uint num1, int num2)
+		{
+			return num1 >> num2;
+		}
+
+		public long RShiftLong(long num1, long num2)
+		{
+			return num1 >> (int)num2;
+		}
+
+		public ulong RShiftUnsignedLong(ulong num1, ulong num2)
+		{
+			return num1 >> (int)num2;
+		}
+
+		public int ShiftByte(byte num)
+		{
+			return num << 8;
+		}
+
+		public int RShiftByte(byte num)
+		{
+			return num >> 8;
+		}
+
+		public uint RShiftByteWithZeroExtension(byte num)
+		{
+			// zero extend -> cast to unsigned -> unsigned shift
+			return (uint)num >> 8;
+		}
+
+		public int RShiftByteWithZeroExtensionReturnAsSigned(byte num)
+		{
+#if CS110
+			// zero extend -> unsigned shift
+			return num >>> 8;
+#else
+			// zero extend -> cast to unsigned -> unsigned shift -> cast to signed
+			return (int)((uint)num >> 8);
+#endif
+		}
+
+		public int RShiftByteAsSByte(byte num)
+		{
+			return (sbyte)num >> 8;
+		}
+
+		public int RShiftSByte(sbyte num)
+		{
+			return num >> 8;
+		}
+
+		public uint RShiftSByteWithZeroExtension(sbyte num)
+		{
+			return (uint)((byte)num >> 4);
+		}
+
+		public uint RShiftSByteWithSignExtension(sbyte num)
+		{
+			// sign extend -> cast to unsigned -> unsigned shift
+			return (uint)num >> 4;
+		}
+
+		public int RShiftSByteWithSignExtensionReturnAsSigned(sbyte num)
+		{
+#if CS110
+			// sign extend -> unsigned shift
+			return num >>> 4;
+#else
+			// sign extend -> cast to unsigned -> unsigned shift -> cast to signed
+			return (int)((uint)num >> 4);
+#endif
+		}
+		public int RShiftSByteAsByte(sbyte num)
+		{
+			return (byte)num >> 8;
+		}
+		#endregion
+
+		public int GetHashCode(long num)
+		{
+			return (int)num ^ (int)(num >> 32);
+		}
+
+		public void TernaryOp(Random a, Random b, bool c)
+		{
+			if ((c ? a : b) == null)
+			{
+				Console.WriteLine();
+			}
+		}
+
+		public void OperatorIs(object o)
+		{
+			Console.WriteLine(o is Random);
+			Console.WriteLine(!(o is Random));
+			// If we didn't escape the '_' identifier here, this would look like a discard pattern
+			Console.WriteLine(o is @_);
+		}
+
+		public byte[] CreateArrayWithInt(int length)
+		{
+			return new byte[length];
+		}
+
+		public byte[] CreateArrayWithLong(long length)
+		{
+			return new byte[length];
+		}
+
+		public byte[] CreateArrayWithUInt(uint length)
+		{
+			return new byte[length];
+		}
+
+		public byte[] CreateArrayWithULong(ulong length)
+		{
+			return new byte[length];
+		}
+
+		public byte[] CreateArrayWithShort(short length)
+		{
+			return new byte[length];
+		}
+
+		public byte[] CreateArrayWithUShort(ushort length)
+		{
+			return new byte[length];
+		}
+
+		public byte UseArrayWithInt(int i)
+		{
+			return byteArray[i];
+		}
+
+		public byte UseArrayWithUInt(uint i)
+		{
+			return byteArray[i];
+		}
+
+		public byte UseArrayWithLong(long i)
+		{
+			return byteArray[i];
+		}
+
+		public byte UseArrayWithULong(ulong i)
+		{
+			return byteArray[i];
+		}
+
+		public byte UseArrayWithShort(short i)
+		{
+			return byteArray[i];
+		}
+
+		public byte UseArrayWithUShort(ushort i)
+		{
+			return byteArray[i];
+		}
+
+		public byte UseArrayWithCastToUShort(int i)
+		{
+			// Unchecked cast = truncate to 16 bits
+			return byteArray[(ushort)i];
+		}
+
+		public void EnumSubtractionWithHighBitValues(UIntEnum value)
+		{
+			if (value - UIntEnum.Val1 <= 4)
+			{
+				Console.WriteLine(value - UIntEnum.Val1);
+			}
+		}
+
+		public void EnumSubtractionWithHighBitValues16(UShortEnum value)
+		{
+			// A 16-bit enum member always fits its underlying type as a positive constant,
+			// so the compiler emits it as such and enum-minus-underlying resolves right away.
+			if ((int)(value - 65035) <= 4)
+			{
+				Console.WriteLine((int)(value - 65035));
+			}
+		}
+
+		public void EnumSubtractionWithHighBitValues64(ULongEnum value)
+		{
+			if (value - ULongEnum.Val1 <= 4)
+			{
+				Console.WriteLine(value - ULongEnum.Val1);
+			}
+		}
+
+		public void EnumSubtractionWithZeroExtendedValue(ULongEnum value)
+		{
+			// Val3 is emitted as a zero-extended uint constant (ldc.i4.m1 + conv.u8), so it
+			// must not be reinterpreted as the sign-extended long -1.
+			Console.WriteLine((ulong)(value - uint.MaxValue));
+		}
+
+		public StringComparison EnumDiffNumber(StringComparison data)
+		{
+			return data - 1;
+		}
+
+		public int EnumDiff(StringComparison a, StringComparison b)
+		{
+			return Math.Abs(a - b);
+		}
+
+		public bool CompareDelegatesByValue(Action a, Action b)
+		{
+			return a == b;
+		}
+
+		public bool CompareDelegatesByReference(Action a, Action b)
+		{
+			return (object)a == b;
+		}
+
+		public bool CompareDelegateWithNull(Action a)
+		{
+			return a == null;
+		}
+
+		public bool CompareStringsByValue(string a, string b)
+		{
+			return a == b;
+		}
+
+		public bool CompareStringsByReference(string a, string b)
+		{
+			return (object)a == b;
+		}
+
+		public bool CompareStringWithNull(string a)
+		{
+			return a == null;
+		}
+
+		public bool CompareType(Type a, Type b)
+		{
+			return a == b;
+		}
+
+		public bool CompareTypeByReference(Type a, Type b)
+		{
+			return (object)a == b;
+		}
+
+		public bool CompareTypeWithNull(Type t)
+		{
+			return t == null;
+		}
+
+		public Attribute CallExtensionMethodViaBaseClass(Type type)
+		{
+			return type.GetCustomAttribute<AttributeUsageAttribute>();
+		}
+
+		public decimal ImplicitConversionToDecimal(byte v)
+		{
+			return v;
+		}
+
+		public decimal ImplicitConversionToDecimal(ulong v)
+		{
+			return v;
+		}
+
+		public bool EnumInConditionalOperator(bool b)
+		{
+			return string.Equals("", "", b ? StringComparison.Ordinal : StringComparison.OrdinalIgnoreCase);
+		}
+
+		public bool MethodCallOnEnumConstant()
+		{
+			return AttributeTargets.All.HasFlag(AttributeTargets.Assembly);
+		}
+
+		public static string ImpossibleCast1(int i)
+		{
+			return (string)(object)i;
+		}
+
+		public static string ImpossibleCast2(Action a)
+		{
+			return (string)(object)a;
+		}
+
+		public static bool CompareLast32Bits(long a, long b)
+		{
+			return (int)a == (int)b;
+		}
+
+		public static bool Last32BitsAreZero(long a)
+		{
+			return (int)a == 0;
+		}
+	}
+
+	public enum UIntEnum : uint
+	{
+		Val1 = 4294966795u,
+		Val2 = 4294966799u
+	}
+
+	public enum ULongEnum : ulong
+	{
+		Val1 = 18446744073709551115uL,
+		Val2 = 18446744073709551119uL,
+		Val3 = 4294967295uL
+	}
+
+	public enum UShortEnum : ushort
+	{
+		Val1 = 65035,
+		Val2 = 65039
+	}
+}

ICSharpCode.Decompiler/IL/Transforms/CopyPropagation.cs

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+// Copyright (c) 2011-2015 Daniel Grunwald
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+
+using ICSharpCode.Decompiler.TypeSystem;
+using ICSharpCode.Decompiler.Util;
+
+namespace ICSharpCode.Decompiler.IL.Transforms
+{
+	/// <summary>
+	/// Runs a very simple form of copy propagation.
+	/// Copy propagation is used in two cases:
+	/// 1) assignments from arguments to local variables
+	///    If the target variable is assigned to only once (so always is that argument) and the argument is never changed (no ldarga/starg),
+	///    then we can replace the variable with the argument.
+	/// 2) assignments of address-loading instructions to local variables
+	/// </summary>
+	public class CopyPropagation : IILTransform
+	{
+		public static void Propagate(StLoc store, ILTransformContext context)
+		{
+			Debug.Assert(store.Variable.IsSingleDefinition);
+			Block block = (Block)store.Parent;
+			int i = store.ChildIndex;
+			DoPropagate(store.Variable, store.Value, block, ref i, context);
+		}
+
+		public void Run(ILFunction function, ILTransformContext context)
+		{
+			var splitVariables = new HashSet<ILVariable>(ILVariableEqualityComparer.Instance);
+			foreach (var g in function.Variables.GroupBy(v => v, ILVariableEqualityComparer.Instance))
+			{
+				if (g.Count() > 1)
+				{
+					splitVariables.Add(g.Key);
+				}
+			}
+			foreach (var block in function.Descendants.OfType<Block>())
+			{
+				if (block.Kind != BlockKind.ControlFlow)
+					continue;
+				RunOnBlock(block, context, splitVariables);
+			}
+		}
+
+		static void RunOnBlock(Block block, ILTransformContext context, HashSet<ILVariable> splitVariables = null)
+		{
+			for (int i = 0; i < block.Instructions.Count; i++)
+			{
+				if (block.Instructions[i].MatchStLoc(out ILVariable v, out ILInstruction copiedExpr))
+				{
+					if (v.IsSingleDefinition && v.LoadCount == 0 && v.Kind == VariableKind.StackSlot)
+					{
+						// dead store to stack
+						if (SemanticHelper.IsPure(copiedExpr.Flags))
+						{
+							// no-op -> delete
+							context.Step("remove dead store to stack: no-op -> delete", block.Instructions[i]);
+							block.Instructions.RemoveAt(i);
+							// This can open up new inlining opportunities:
+							int c = ILInlining.InlineInto(block, i, InliningOptions.None, context: context);
+							i -= c + 1;
+						}
+						else
+						{
+							// evaluate the value for its side-effects
+							context.Step("remove dead store to stack: evaluate the value for its side-effects", block.Instructions[i]);
+							copiedExpr.AddILRange(block.Instructions[i]);
+							block.Instructions[i] = copiedExpr;
+							context.EndStep(copiedExpr);
+						}
+					}
+					else if (v.IsSingleDefinition && CanPerformCopyPropagation(v, copiedExpr, splitVariables, context.Settings))
+					{
+						DoPropagate(v, copiedExpr, block, ref i, context);
+					}
+				}
+			}
+		}
+
+		static bool CanPerformCopyPropagation(ILVariable target, ILInstruction value, HashSet<ILVariable> splitVariables, DecompilerSettings settings)
+		{
+			Debug.Assert(target.StackType == value.ResultType);
+			if (target.Type.IsSmallIntegerType())
+				return false;
+			if (splitVariables != null && splitVariables.Contains(target))
+			{
+				return false; // non-local code move might change semantics when there's split variables
+			}
+			switch (value.OpCode)
+			{
+				case OpCode.LdLoca:
+				case OpCode.LdsFlda:
+					// All address-loading instructions always return the same value for a given operand/argument combination,
+					// so they can be safely copied.
+					// ... except for LdElema and LdFlda, because those might throw an exception, and we don't want to
+					// change the place where the exception is thrown.
+					return true;
+				case OpCode.LdElema:
+				case OpCode.LdFlda:
+					return !settings.UseRefLocalsForAccurateOrderOfEvaluation;
+				case OpCode.LdLoc:
+					var v = ((LdLoc)value).Variable;
+					if (splitVariables != null && splitVariables.Contains(v))
+					{
+						return false; // non-local code move might change semantics when there's split variables
+					}
+					switch (v.Kind)
+					{
+						case VariableKind.Parameter:
+							// Parameters can be copied only if they aren't assigned to (directly or indirectly via ldarga)
+							// note: the initialization by the caller is the first store -> StoreCount must be 1
+							return v.IsSingleDefinition;
+						default:
+							// Variables can be copied if both are single-definition.
+							// To avoid removing too many variables, we do this only if the target
+							// is either a stackslot or a ref local.
+							Debug.Assert(target.IsSingleDefinition);
+							return v.IsSingleDefinition && (target.Kind == VariableKind.StackSlot || target.StackType == StackType.Ref);
+					}
+				default:
+					// All instructions without special behavior that target a stack-variable can be copied.
+					return value.Flags == InstructionFlags.None && value.Children.Count == 0 && target.Kind == VariableKind.StackSlot;
+			}
+		}
+
+		static void DoPropagate(ILVariable v, ILInstruction copiedExpr, Block block, ref int i, ILTransformContext context)
+		{
+			context.Step($"Copy propagate {v.Name}", copiedExpr);
+			int firstUninlinedArg = i;
+			// un-inline the arguments of the ldArg instruction
+			ILVariable[] uninlinedArgs = new ILVariable[copiedExpr.Children.Count];
+			for (int j = 0; j < uninlinedArgs.Length; j++)
+			{
+				var arg = copiedExpr.Children[j];
+				var type = arg.InferType(context.TypeSystem);
+				uninlinedArgs[j] = new ILVariable(VariableKind.StackSlot, type, arg.ResultType) {
+					Name = "C_" + arg.StartILOffset,
+					HasGeneratedName = true,
+				};
+				block.Instructions.Insert(i++, new StLoc(uninlinedArgs[j], arg));
+			}
+			v.Function.Variables.AddRange(uninlinedArgs);
+			// perform copy propagation:
+			foreach (var expr in v.LoadInstructions.ToArray())
+			{
+				var clone = copiedExpr.Clone();
+				for (int j = 0; j < uninlinedArgs.Length; j++)
+				{
+					clone.Children[j].ReplaceWith(new LdLoc(uninlinedArgs[j]));
+				}
+				// We are copying an expression from far away, reusing the ILRange would result in incorrect sequence points.
+				clone.SetILRange(new Interval());
+				if (expr.SlotInfo == StObj.TargetSlot && clone.HasDirectFlag(InstructionFlags.MayThrow)
+					&& !expr.Parent.SatisfiesSlotRestrictionForInlining(expr.ChildIndex, clone))
+				{
+					// A LdFlda/LdElema used as StObj target has to delay its exception, because C#
+					// computes the value to be stored before dereferencing the target. Accept the
+					// changed point at which the exception is thrown, mirroring
+					// InliningOptions.AllowChangingOrderOfEvaluationForExceptions in ILInlining.
+					// Unlike inlining, copy propagation has no third option of just giving up: the
+					// defining store is gone by the end of this loop, so every load must be replaced.
+					// Refusing the copy is only possible before propagation starts, which is what
+					// CanPerformCopyPropagation does when ref locals are requested; the assert
+					// guards the public Propagate() entry point, which bypasses that check.
+					Debug.Assert(!context.Settings.UseRefLocalsForAccurateOrderOfEvaluation);
+					if (clone is LdFlda ldflda)
+						ldflda.DelayExceptions = true;
+					else if (clone is LdElema ldelema)
+						ldelema.DelayExceptions = true;
+				}
+				expr.ReplaceWith(clone);
+			}
+			block.Instructions.RemoveAt(i);
+			int c = ILInlining.InlineInto(block, i, InliningOptions.None, context: context);
+			i -= c + 1;
+			if (uninlinedArgs.Length > 0)
+			{
+				// The stores holding the un-inlined arguments are themselves copy-propagation
+				// candidates: copying an ldflda leaves its target address behind in a stack slot,
+				// and if that address is e.g. an ldloca it can be copied as well. They sit before
+				// the current position, so rewind far enough for the caller's loop to visit them;
+				// otherwise a multiply-loaded stack slot survives as a spurious ref local.
+				i = Math.Min(i, firstUninlinedArg - 1);
+			}
+		}
+	}
+}
+