Fix #1189: Avoid crashing on invalid IL bytes.

ICSharpCode.Decompiler/CSharp/OutputVisitor/InsertMissingTokensDecorator.cs

@@ -68,13 +68,18 @@ namespace ICSharpCode.Decompiler.CSharp.OutputVisitor
 		
 		public override void WriteToken(Role role, string token)
 		{
-			EmptyStatement node = nodes.Peek().LastOrDefault() as EmptyStatement;
-			if (node == null) {
-				CSharpTokenNode t = new CSharpTokenNode(locationProvider.Location, (TokenRole)role);
-				t.Role = role;
-				currentList.Add(t);
-			} else {
-				node.Location = locationProvider.Location;
+			switch (nodes.Peek().LastOrDefault()) {
+				case EmptyStatement emptyStatement:
+					emptyStatement.Location = locationProvider.Location;
+					break;
+				case ErrorExpression errorExpression:
+					errorExpression.Location = locationProvider.Location;
+					break;
+				default:
+					CSharpTokenNode t = new CSharpTokenNode(locationProvider.Location, (TokenRole)role);
+					t.Role = role;
+					currentList.Add(t);
+					break;
 			}
 			base.WriteToken(role, token);
 		}

ICSharpCode.Decompiler/CSharp/RequiredNamespaceCollector.cs

@@ -188,12 +188,24 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 
 			foreach (var region in method.ExceptionRegions) {
-				if (region.CatchType.IsNil) continue;
-				CollectNamespacesForTypeReference(module.ResolveType(region.CatchType, genericContext), namespaces);
+				if (region.CatchType.IsNil)
+					continue;
+				IType ty;
+				try {
+					ty = module.ResolveType(region.CatchType, genericContext);
+				} catch (BadImageFormatException) {
+					continue;
+				}
+				CollectNamespacesForTypeReference(ty, namespaces);
 			}
 
 			while (instructions.RemainingBytes > 0) {
-				var opCode = instructions.DecodeOpCode();
+				ILOpCode opCode;
+				try {
+					opCode = instructions.DecodeOpCode();
+				} catch (BadImageFormatException) {
+					return;
+				}
 				switch (opCode.GetOperandType()) {
 					case Metadata.OperandType.Field:
 					case Metadata.OperandType.Method:
@@ -201,24 +213,46 @@ namespace ICSharpCode.Decompiler.CSharp
 					case Metadata.OperandType.Tok:
 					case Metadata.OperandType.Type:
 						var handle = MetadataTokenHelpers.EntityHandleOrNil(instructions.ReadInt32());
-						if (handle.IsNil) break;
+						if (handle.IsNil)
+							break;
 						switch (handle.Kind) {
 							case HandleKind.TypeDefinition:
 							case HandleKind.TypeReference:
 							case HandleKind.TypeSpecification:
-								CollectNamespacesForTypeReference(module.ResolveType(handle, genericContext), namespaces);
+								IType type;
+								try {
+									type = module.ResolveType(handle, genericContext);
+								} catch (BadImageFormatException) {
+									break;
+								}
+								CollectNamespacesForTypeReference(type, namespaces);
 								break;
 							case HandleKind.FieldDefinition:
 							case HandleKind.MethodDefinition:
 							case HandleKind.MethodSpecification:
 							case HandleKind.MemberReference:
-								CollectNamespacesForMemberReference(module.ResolveEntity(handle, genericContext) as IMember,
-									module, namespaces);
+								IMember member;
+								try {
+									member = module.ResolveEntity(handle, genericContext) as IMember;
+								} catch (BadImageFormatException) {
+									break;
+								}
+								CollectNamespacesForMemberReference(member, module, namespaces);
 								break;
 							case HandleKind.StandaloneSignature:
-								var sig = metadata.GetStandaloneSignature((StandaloneSignatureHandle)handle);
+								StandaloneSignature sig;
+								try {
+									sig = metadata.GetStandaloneSignature((StandaloneSignatureHandle)handle);
+								} catch (BadImageFormatException) {
+									break;
+								}
 								if (sig.GetKind() == StandaloneSignatureKind.Method) {
-									var methodSig = module.DecodeMethodSignature((StandaloneSignatureHandle)handle, genericContext);
+									MethodSignature<IType> methodSig;
+									try {
+										methodSig = module.DecodeMethodSignature((StandaloneSignatureHandle)handle, genericContext);
+									} catch (BadImageFormatException) {
+										break;
+									}
 									CollectNamespacesForTypeReference(methodSig.ReturnType, namespaces);
 									foreach (var paramType in methodSig.ParameterTypes) {
 										CollectNamespacesForTypeReference(paramType, namespaces);
@@ -228,7 +262,11 @@ namespace ICSharpCode.Decompiler.CSharp
 						}
 						break;
 					default:
-						instructions.SkipOperand(opCode);
+						try {
+							instructions.SkipOperand(opCode);
+						} catch (BadImageFormatException) {
+							return;
+						}
 						break;
 				}
 			}

ICSharpCode.Decompiler/CSharp/Syntax/Expressions/ErrorExpression.cs

@@ -29,17 +29,17 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 {
 	public class ErrorExpression : Expression
 	{
-		TextLocation location;
+		public TextLocation Location { get; set; }
 
 		public override TextLocation StartLocation {
 			get {
-				return location;
+				return Location;
 			}
 		}
 		
 		public override TextLocation EndLocation {
 			get {
-				return location;
+				return Location;
 			}
 		}
 
@@ -54,7 +54,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 
 		public ErrorExpression (TextLocation location)
 		{
-			this.location = location;
+			this.Location = location;
 		}
 
 		public ErrorExpression (string error)
@@ -64,7 +64,7 @@ namespace ICSharpCode.Decompiler.CSharp.Syntax
 
 		public ErrorExpression (string error, TextLocation location)
 		{
-			this.location = location;
+			this.Location = location;
 			this.Error = error;
 		}
 

ICSharpCode.Decompiler/IL/ILReader.cs

@@ -388,7 +388,7 @@ namespace ICSharpCode.Decompiler.IL
 				} catch (BadImageFormatException ex) {
 					decodedInstruction = new InvalidBranch(ex.Message);
 				}
-				if (decodedInstruction.ResultType == StackType.Unknown)
+				if (decodedInstruction.ResultType == StackType.Unknown && decodedInstruction.OpCode != OpCode.InvalidBranch && UnpackPush(decodedInstruction).OpCode != OpCode.InvalidExpression)
 					Warn("Unknown result type (might be due to invalid IL or missing references)");
 				decodedInstruction.CheckInvariant(ILPhase.InILReader);
 				int end = reader.Offset;

ICSharpCode.Decompiler/TypeSystem/MetadataModule.cs

@@ -278,9 +278,7 @@ namespace ICSharpCode.Decompiler.TypeSystem
 				case HandleKind.ExportedType:
 					return ResolveForwardedType(metadata.GetExportedType((ExportedTypeHandle)typeRefDefSpec));
 				default:
-					Debug.Fail("Not a type handle");
-					ty = SpecialType.UnknownType;
-					break;
+					throw new BadImageFormatException("Not a type handle");
 			}
 			ty = ApplyAttributeTypeVisitor.ApplyAttributesToType(ty, Compilation, typeAttributes, metadata, customOptions);
 			return ty;