Add transform for new T().

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

@@ -1,4 +1,20 @@
-using System;
+// 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.
 
 namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 {

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Generics.il

@@ -10,7 +10,7 @@
   .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
   .ver 4:0:0:0
 }
-.assembly org2btap
+.assembly lb3mdocq
 {
   .custom instance void [mscorlib]System.Runtime.CompilerServices.CompilationRelaxationsAttribute::.ctor(int32) = ( 01 00 08 00 00 00 00 00 ) 
   .custom instance void [mscorlib]System.Runtime.CompilerServices.RuntimeCompatibilityAttribute::.ctor() = ( 01 00 01 00 54 02 16 57 72 61 70 4E 6F 6E 45 78   // ....T..WrapNonEx
@@ -20,15 +20,15 @@
   .hash algorithm 0x00008004
   .ver 0:0:0:0
 }
-.module org2btap.dll
-// MVID: {C17EE898-3151-4FD3-9C62-06322F89471A}
+.module lb3mdocq.dll
+// MVID: {4412C112-CBEB-40EB-BC42-5C82526C8657}
 .custom instance void [mscorlib]System.Security.UnverifiableCodeAttribute::.ctor() = ( 01 00 00 00 ) 
 .imagebase 0x10000000
 .file alignment 0x00000200
 .stackreserve 0x00100000
 .subsystem 0x0003       // WINDOWS_CUI
 .corflags 0x00000001    //  ILONLY
-// Image base: 0x02570000
+// Image base: 0x03060000
 
 
 // =============== CLASS MEMBERS DECLARATION ===================
@@ -135,13 +135,14 @@
     IL_0026:  ret
   } // end of method Generics::New
 
-  .method public hidebysig static bool  IsNull<T>(!!T t) cil managed
+  .method public hidebysig instance bool 
+          IsNull<T>(!!T t) cil managed
   {
     // Code size       15 (0xf)
     .maxstack  2
     .locals init (bool V_0)
     IL_0000:  nop
-    IL_0001:  ldarg.0
+    IL_0001:  ldarg.1
     IL_0002:  box        !!T
     IL_0007:  ldnull
     IL_0008:  ceq

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Generics.opt.il

@@ -10,7 +10,7 @@
   .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
   .ver 4:0:0:0
 }
-.assembly '4ebood3j'
+.assembly sxsfxc4c
 {
   .custom instance void [mscorlib]System.Runtime.CompilerServices.CompilationRelaxationsAttribute::.ctor(int32) = ( 01 00 08 00 00 00 00 00 ) 
   .custom instance void [mscorlib]System.Runtime.CompilerServices.RuntimeCompatibilityAttribute::.ctor() = ( 01 00 01 00 54 02 16 57 72 61 70 4E 6F 6E 45 78   // ....T..WrapNonEx
@@ -20,15 +20,15 @@
   .hash algorithm 0x00008004
   .ver 0:0:0:0
 }
-.module '4ebood3j.dll'
-// MVID: {EFF51081-05A0-430F-B639-218464AEAF1E}
+.module sxsfxc4c.dll
+// MVID: {4BDFEFB1-623B-4D1C-B489-AE8EC4D00CF2}
 .custom instance void [mscorlib]System.Security.UnverifiableCodeAttribute::.ctor() = ( 01 00 00 00 ) 
 .imagebase 0x10000000
 .file alignment 0x00000200
 .stackreserve 0x00100000
 .subsystem 0x0003       // WINDOWS_CUI
 .corflags 0x00000001    //  ILONLY
-// Image base: 0x00C40000
+// Image base: 0x02FA0000
 
 
 // =============== CLASS MEMBERS DECLARATION ===================
@@ -122,11 +122,12 @@
     IL_001f:  ret
   } // end of method Generics::New
 
-  .method public hidebysig static bool  IsNull<T>(!!T t) cil managed
+  .method public hidebysig instance bool 
+          IsNull<T>(!!T t) cil managed
   {
     // Code size       10 (0xa)
     .maxstack  8
-    IL_0000:  ldarg.0
+    IL_0000:  ldarg.1
     IL_0001:  box        !!T
     IL_0006:  ldnull
     IL_0007:  ceq

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Generics.opt.roslyn.il

@@ -25,14 +25,14 @@
   .ver 0:0:0:0
 }
 .module Generics.dll
-// MVID: {A68CE966-2788-410B-9ADC-67827754D69A}
+// MVID: {6515FC2D-ED0B-41CF-9FD2-8CD5192CF5A1}
 .custom instance void [mscorlib]System.Security.UnverifiableCodeAttribute::.ctor() = ( 01 00 00 00 ) 
 .imagebase 0x10000000
 .file alignment 0x00000200
 .stackreserve 0x00100000
 .subsystem 0x0003       // WINDOWS_CUI
 .corflags 0x00000001    //  ILONLY
-// Image base: 0x007F0000
+// Image base: 0x01880000
 
 
 // =============== CLASS MEMBERS DECLARATION ===================
@@ -113,11 +113,12 @@
     IL_0005:  ret
   } // end of method Generics::New
 
-  .method public hidebysig static bool  IsNull<T>(!!T t) cil managed
+  .method public hidebysig instance bool 
+          IsNull<T>(!!T t) cil managed
   {
     // Code size       10 (0xa)
     .maxstack  8
-    IL_0000:  ldarg.0
+    IL_0000:  ldarg.1
     IL_0001:  box        !!T
     IL_0006:  ldnull
     IL_0007:  ceq

ICSharpCode.Decompiler.Tests/TestCases/Pretty/Generics.roslyn.il

@@ -25,14 +25,14 @@
   .ver 0:0:0:0
 }
 .module Generics.dll
-// MVID: {ADEAC82A-8D93-4D9A-B37E-3FC39CBDC54B}
+// MVID: {9BC41AF0-27DC-4022-8C9C-4D7039122350}
 .custom instance void [mscorlib]System.Security.UnverifiableCodeAttribute::.ctor() = ( 01 00 00 00 ) 
 .imagebase 0x10000000
 .file alignment 0x00000200
 .stackreserve 0x00100000
 .subsystem 0x0003       // WINDOWS_CUI
 .corflags 0x00000001    //  ILONLY
-// Image base: 0x007E0000
+// Image base: 0x03030000
 
 
 // =============== CLASS MEMBERS DECLARATION ===================
@@ -129,13 +129,14 @@
     IL_000a:  ret
   } // end of method Generics::New
 
-  .method public hidebysig static bool  IsNull<T>(!!T t) cil managed
+  .method public hidebysig instance bool 
+          IsNull<T>(!!T t) cil managed
   {
     // Code size       15 (0xf)
     .maxstack  2
     .locals init (bool V_0)
     IL_0000:  nop
-    IL_0001:  ldarg.0
+    IL_0001:  ldarg.1
     IL_0002:  box        !!T
     IL_0007:  ldnull
     IL_0008:  ceq

ICSharpCode.Decompiler/CSharp/Transforms/ReplaceMethodCallsWithOperators.cs

@@ -98,6 +98,11 @@ namespace ICSharpCode.Decompiler.CSharp.Transforms
 						}
 					}
 					break;
+				case "System.Activator.CreateInstance":
+					if (method.TypeArguments.Count == 1 && arguments.Length == 0 && method.TypeArguments[0].Kind == TypeKind.TypeParameter) {
+						invocationExpression.ReplaceWith(new ObjectCreateExpression(context.TypeSystemAstBuilder.ConvertType(method.TypeArguments.First())));
+					}
+					break;
 			}
 			
 			BinaryOperatorType? bop = GetBinaryOperatorTypeFromMetadataName(method.Name);

ICSharpCode.Decompiler/IL/Transforms/NullableLiftingTransform.cs

@@ -143,6 +143,10 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 						// (a.GetValueOrDefault() == b.GetValueOrDefault()) ? (a.HasValue != b.HasValue) : true
 						// => a != b
 						return LiftCSharpEqualityComparison(comp, ComparisonKind.Inequality, trueInst);
+					} else if (IsGenericNewPattern(condition, trueInst, falseInst)) {
+						// (default(T) == null) ? Activator.CreateInstance<T>() : default(T)
+						// => Activator.CreateInstance<T>()
+						return trueInst;
 					}
 				} else {
 					// Not (in)equality, but one of < <= > >=.
@@ -233,6 +237,18 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			return null;
 		}
 
+		private bool IsGenericNewPattern(ILInstruction condition, ILInstruction trueInst, ILInstruction falseInst)
+		{
+			// (default(T) == null) ? Activator.CreateInstance<T>() : default(T)
+			return falseInst.MatchDefaultValue(out var type) &&
+				(trueInst is Call c && c.Method.FullName == "System.Activator.CreateInstance" && c.Method.TypeArguments.Count == 1) &&
+				type.Kind == TypeKind.TypeParameter &&
+				condition.MatchCompEquals(out var left, out var right) &&
+				left.MatchDefaultValue(out var type2) &&
+				type.Equals(type2) &&
+				right.MatchLdNull();
+		}
+
 		private bool MatchThreeValuedLogicConditionPattern(ILInstruction condition, out ILVariable nullable1, out ILVariable nullable2)
 		{
 			// Try to match: nullable1.GetValueOrDefault() || (!nullable2.GetValueOrDefault() && !nullable1.HasValue)