source: trunk/sources/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.Cecil-5.5.0/CecilLoader.cs @ 13397

// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
// 
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// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
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// 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
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using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Threading;
using ICSharpCode.NRefactory.Documentation;
using ICSharpCode.NRefactory.Semantics;
using ICSharpCode.NRefactory.TypeSystem.Implementation;
using ICSharpCode.NRefactory.Utils;
using Mono.Cecil;


namespace ICSharpCode.NRefactory.TypeSystem
{
  /// <summary>
  /// Allows loading an IProjectContent from an already compiled assembly.
  /// </summary>
  /// <remarks>Instance methods are not thread-safe; you need to create multiple instances of CecilLoader
  /// if you want to load multiple project contents in parallel.</remarks>
  public sealed class CecilLoader : AssemblyLoader
  {
    /// <summary>
    /// Version number of the cecil loader.
    /// Should be incremented when fixing bugs in the cecil loader so that project contents cached on disk
    /// (which might be incorrect due to the bug) are re-created.
    /// </summary>
    const int cecilLoaderVersion = 1;
    
    #region Options
    // Most options are defined in the AssemblyLoader base class
    
    /// <summary>
    /// Specifies whether to use lazy loading. The default is false.
    /// If this property is set to true, the CecilLoader will not copy all the relevant information
    /// out of the Cecil object model, but will maintain references to the Cecil objects.
    /// This speeds up the loading process and avoids loading unnecessary information, but it causes
    /// the Cecil objects to stay in memory (which can significantly increase memory usage).
    /// It also prevents serialization of the Cecil-loaded type system.
    /// </summary>
    /// <remarks>
    /// Because the type system can be used on multiple threads, but Cecil is not
    /// thread-safe for concurrent read access, the CecilLoader will lock on the <see cref="ModuleDefinition"/> instance
    /// for every delay-loading operation.
    /// If you access the Cecil objects directly in your application, you may need to take the same lock.
    /// </remarks>
    public bool LazyLoad { get; set; }
    
    /// <summary>
    /// This delegate gets executed whenever an entity was loaded.
    /// </summary>
    /// <remarks>
    /// This callback may be to build a dictionary that maps between
    /// entities and cecil objects.
    /// Warning: if delay-loading is used and the type system is accessed by multiple threads,
    /// the callback may be invoked concurrently on multiple threads.
    /// </remarks>
    [CLSCompliant(false)]
    public Action<IUnresolvedEntity, MemberReference> OnEntityLoaded { get; set; }
    
    /// <summary>
    /// Gets a value indicating whether this instance stores references to the cecil objects.
    /// </summary>
    /// <value>
    /// <c>true</c> if this instance has references to the cecil objects; otherwise, <c>false</c>.
    /// </value>
    public bool HasCecilReferences { get { return typeSystemTranslationTable != null; } }
    #endregion
    
    ModuleDefinition currentModule;
    CecilUnresolvedAssembly currentAssembly;
    
    /// <summary>
    /// Initializes a new instance of the <see cref="ICSharpCode.NRefactory.TypeSystem.CecilLoader"/> class.
    /// </summary>
    public CecilLoader()
    {
    }
    
    /// <summary>
    /// Initializes a new instance of the <see cref="ICSharpCode.NRefactory.TypeSystem.CecilLoader"/> class.
    /// </summary>
    /// <param name='createCecilReferences'>
    /// If true references to the cecil objects are hold. In this case the cecil loader can do a type system -> cecil mapping.
    /// </param>
    [Obsolete("The built-in entity<->cecil mapping is obsolete. Use the OnEntityLoaded callback instead!")]
    public CecilLoader(bool createCecilReferences) : this()
    {
      if (createCecilReferences)
        typeSystemTranslationTable = new Dictionary<object, object> ();
    }
    
    /// <summary>
    /// Creates a nested CecilLoader for lazy-loading.
    /// </summary>
    private CecilLoader(CecilLoader loader)
    {
      // use a shared typeSystemTranslationTable
      this.typeSystemTranslationTable = loader.typeSystemTranslationTable;
      this.IncludeInternalMembers = loader.IncludeInternalMembers;
      this.LazyLoad = loader.LazyLoad;
      this.OnEntityLoaded = loader.OnEntityLoaded;
      this.currentModule = loader.currentModule;
      this.currentAssembly = loader.currentAssembly;
      // don't use interning - the interning provider is most likely not thread-safe
      this.interningProvider = InterningProvider.Dummy;
      // don't use cancellation for delay-loaded members
    }

    #region Load From AssemblyDefinition
    /// <summary>
    /// Loads the assembly definition into a project content.
    /// </summary>
    /// <returns>Unresolved type system representing the assembly</returns>
    [CLSCompliant(false)]
    public IUnresolvedAssembly LoadAssembly(AssemblyDefinition assemblyDefinition)
    {
      if (assemblyDefinition == null)
        throw new ArgumentNullException("assemblyDefinition");
      return LoadModule(assemblyDefinition.MainModule);
    }
    
    /// <summary>
    /// Loads the module definition into a project content.
    /// </summary>
    /// <returns>Unresolved type system representing the assembly</returns>
    [CLSCompliant(false)]
    public IUnresolvedAssembly LoadModule(ModuleDefinition moduleDefinition)
    {
      if (moduleDefinition == null)
        throw new ArgumentNullException("moduleDefinition");
      
      this.currentModule = moduleDefinition;
      
      // Read assembly and module attributes
      IList<IUnresolvedAttribute> assemblyAttributes = new List<IUnresolvedAttribute>();
      IList<IUnresolvedAttribute> moduleAttributes = new List<IUnresolvedAttribute>();
      AssemblyDefinition assemblyDefinition = moduleDefinition.Assembly;
      if (assemblyDefinition != null) {
        AddAttributes(assemblyDefinition, assemblyAttributes);
      }
      AddAttributes(moduleDefinition, moduleAttributes);
      
      assemblyAttributes = interningProvider.InternList(assemblyAttributes);
      moduleAttributes = interningProvider.InternList(moduleAttributes);
      
      this.currentAssembly = new CecilUnresolvedAssembly(assemblyDefinition != null ? assemblyDefinition.Name.FullName : moduleDefinition.Name, this.DocumentationProvider);
      currentAssembly.Location = moduleDefinition.FullyQualifiedName;
      currentAssembly.AssemblyAttributes.AddRange(assemblyAttributes);
      currentAssembly.ModuleAttributes.AddRange(assemblyAttributes);
      
      // Register type forwarders:
      foreach (ExportedType type in moduleDefinition.ExportedTypes) {
        if (type.IsForwarder) {
          int typeParameterCount;
          string ns = type.Namespace;
          string name = ReflectionHelper.SplitTypeParameterCountFromReflectionName(type.Name, out typeParameterCount);
          ns = interningProvider.Intern(ns);
          name = interningProvider.Intern(name);
          var typeRef = new GetClassTypeReference(GetAssemblyReference(type.Scope), ns, name, typeParameterCount);
          typeRef = interningProvider.Intern(typeRef);
          var key = new TopLevelTypeName(ns, name, typeParameterCount);
          currentAssembly.AddTypeForwarder(key, typeRef);
        }
      }
      
      // Create and register all types:
      CecilLoader cecilLoaderCloneForLazyLoading = LazyLoad ? new CecilLoader(this) : null;
      List<TypeDefinition> cecilTypeDefs = new List<TypeDefinition>();
      List<DefaultUnresolvedTypeDefinition> typeDefs = new List<DefaultUnresolvedTypeDefinition>();
      foreach (TypeDefinition td in moduleDefinition.Types) {
        this.CancellationToken.ThrowIfCancellationRequested();
        if (this.IncludeInternalMembers || (td.Attributes & TypeAttributes.VisibilityMask) == TypeAttributes.Public) {
          string name = td.Name;
          if (name.Length == 0)
            continue;
          
          if (this.LazyLoad) {
            var t = new LazyCecilTypeDefinition(cecilLoaderCloneForLazyLoading, td);
            currentAssembly.AddTypeDefinition(t);
            RegisterCecilObject(t, td);
          } else {
            var t = CreateTopLevelTypeDefinition(td);
            cecilTypeDefs.Add(td);
            typeDefs.Add(t);
            currentAssembly.AddTypeDefinition(t);
            // The registration will happen after the members are initialized
          }
        }
      }
      // Initialize the type's members:
      for (int i = 0; i < typeDefs.Count; i++) {
        InitTypeDefinition(cecilTypeDefs[i], typeDefs[i]);
      }
      
      AddToTypeSystemTranslationTable(this.currentAssembly, assemblyDefinition);
      // Freezing the assembly here is important:
      // otherwise it will be frozen when a compilation is first created
      // from it. But freezing has the effect of changing some collection instances
      // (to ReadOnlyCollection). This hidden mutation was causing a crash
      // when the FastSerializer was saving the assembly at the same time as
      // the first compilation was created from it.
      // By freezing the assembly now, we ensure it is usable on multiple
      // threads without issues.
      currentAssembly.Freeze();
      
      var result = this.currentAssembly;
      this.currentAssembly = null;
      this.currentModule = null;
      return result;
    }
    
    /// <summary>
    /// Sets the current module.
    /// This causes ReadTypeReference() to use <see cref="DefaultAssemblyReference.CurrentAssembly"/> for references
    /// in that module.
    /// </summary>
    [CLSCompliant(false)]
    public void SetCurrentModule(ModuleDefinition module)
    {
      this.currentModule = module;
    }
    
    /// <summary>
    /// Loads a type from Cecil.
    /// </summary>
    /// <param name="typeDefinition">The Cecil TypeDefinition.</param>
    /// <returns>ITypeDefinition representing the Cecil type.</returns>
    [CLSCompliant(false)]
    public IUnresolvedTypeDefinition LoadType(TypeDefinition typeDefinition)
    {
      if (typeDefinition == null)
        throw new ArgumentNullException("typeDefinition");
      var td = CreateTopLevelTypeDefinition(typeDefinition);
      InitTypeDefinition(typeDefinition, td);
      return td;
    }
    #endregion
    
    #region IUnresolvedAssembly implementation
    [Serializable, FastSerializerVersion(cecilLoaderVersion)]
    sealed class CecilUnresolvedAssembly : DefaultUnresolvedAssembly, IDocumentationProvider
    {
      readonly IDocumentationProvider documentationProvider;
      
      public CecilUnresolvedAssembly(string fullAssemblyName, IDocumentationProvider documentationProvider)
        : base(fullAssemblyName)
      {
        this.documentationProvider = documentationProvider;
      }
      
      DocumentationComment IDocumentationProvider.GetDocumentation(IEntity entity)
      {
        if (documentationProvider != null)
          return documentationProvider.GetDocumentation(entity);
        else
          return null;
      }
    }
    #endregion
    
    #region Load Assembly From Disk
    public override IUnresolvedAssembly LoadAssemblyFile(string fileName)
    {
      if (fileName == null)
        throw new ArgumentNullException("fileName");
      var param = new ReaderParameters { AssemblyResolver = new DummyAssemblyResolver() };
      ModuleDefinition module = ModuleDefinition.ReadModule(fileName, param);
      return LoadModule(module);
    }
    
    // used to prevent Cecil from loading referenced assemblies
    sealed class DummyAssemblyResolver : IAssemblyResolver
    {
      public AssemblyDefinition Resolve(AssemblyNameReference name)
      {
        return null;
      }
      
      public AssemblyDefinition Resolve(string fullName)
      {
        return null;
      }
      
      public AssemblyDefinition Resolve(AssemblyNameReference name, ReaderParameters parameters)
      {
        return null;
      }
      
      public AssemblyDefinition Resolve(string fullName, ReaderParameters parameters)
      {
        return null;
      }
    }
    #endregion
    
    #region Read Type Reference
    /// <summary>
    /// Reads a type reference.
    /// </summary>
    /// <param name="type">The Cecil type reference that should be converted into
    /// a type system type reference.</param>
    /// <param name="typeAttributes">Attributes associated with the Cecil type reference.
    /// This is used to support the 'dynamic' type.</param>
    [CLSCompliant(false)]
    public ITypeReference ReadTypeReference(TypeReference type, ICustomAttributeProvider typeAttributes = null)
    {
      int typeIndex = 0;
      return CreateType(type, typeAttributes, ref typeIndex);
    }
    
    ITypeReference CreateType(TypeReference type, ICustomAttributeProvider typeAttributes, ref int typeIndex)
    {
      while (type is OptionalModifierType || type is RequiredModifierType) {
        type = ((TypeSpecification)type).ElementType;
      }
      if (type == null) {
        return SpecialType.UnknownType;
      }
      
      if (type is Mono.Cecil.ByReferenceType) {
        typeIndex++;
        return interningProvider.Intern(
          new ByReferenceTypeReference(
            CreateType(
              (type as Mono.Cecil.ByReferenceType).ElementType,
              typeAttributes, ref typeIndex)));
      } else if (type is Mono.Cecil.PointerType) {
        typeIndex++;
        return interningProvider.Intern(
          new PointerTypeReference(
            CreateType(
              (type as Mono.Cecil.PointerType).ElementType,
              typeAttributes, ref typeIndex)));
      } else if (type is Mono.Cecil.ArrayType) {
        typeIndex++;
        return interningProvider.Intern(
          new ArrayTypeReference(
            CreateType(
              (type as Mono.Cecil.ArrayType).ElementType,
              typeAttributes, ref typeIndex),
            (type as Mono.Cecil.ArrayType).Rank));
      } else if (type is GenericInstanceType) {
        GenericInstanceType gType = (GenericInstanceType)type;
        ITypeReference baseType = CreateType(gType.ElementType, typeAttributes, ref typeIndex);
        ITypeReference[] para = new ITypeReference[gType.GenericArguments.Count];
        for (int i = 0; i < para.Length; ++i) {
          typeIndex++;
          para[i] = CreateType(gType.GenericArguments[i], typeAttributes, ref typeIndex);
        }
        return interningProvider.Intern(new ParameterizedTypeReference(baseType, para));
      } else if (type is GenericParameter) {
        GenericParameter typeGP = (GenericParameter)type;
        return TypeParameterReference.Create(typeGP.Owner is MethodDefinition ? SymbolKind.Method : SymbolKind.TypeDefinition, typeGP.Position);
      } else if (type.IsNested) {
        ITypeReference typeRef = CreateType(type.DeclaringType, typeAttributes, ref typeIndex);
        int partTypeParameterCount;
        string namepart = ReflectionHelper.SplitTypeParameterCountFromReflectionName(type.Name, out partTypeParameterCount);
        namepart = interningProvider.Intern(namepart);
        return interningProvider.Intern(new NestedTypeReference(typeRef, namepart, partTypeParameterCount));
      } else {
        string ns = interningProvider.Intern(type.Namespace ?? string.Empty);
        string name = type.Name;
        if (name == null)
          throw new InvalidOperationException("type.Name returned null. Type: " + type.ToString());
        
        if (name == "Object" && ns == "System" && HasDynamicAttribute(typeAttributes, typeIndex)) {
          return SpecialType.Dynamic;
        } else {
          int typeParameterCount;
          name = ReflectionHelper.SplitTypeParameterCountFromReflectionName(name, out typeParameterCount);
          name = interningProvider.Intern(name);
          if (currentAssembly != null) {
            IUnresolvedTypeDefinition c = currentAssembly.GetTypeDefinition(ns, name, typeParameterCount);
            if (c != null)
              return c;
          }
          return interningProvider.Intern(new GetClassTypeReference(GetAssemblyReference(type.Scope), ns, name, typeParameterCount));
        }
      }
    }
    
    IAssemblyReference GetAssemblyReference(IMetadataScope scope)
    {
      if (scope == null || scope == currentModule)
        return DefaultAssemblyReference.CurrentAssembly;
      else
        return interningProvider.Intern(new DefaultAssemblyReference(scope.Name));
    }
    
    static bool HasDynamicAttribute(ICustomAttributeProvider attributeProvider, int typeIndex)
    {
      if (attributeProvider == null || !attributeProvider.HasCustomAttributes)
        return false;
      foreach (CustomAttribute a in attributeProvider.CustomAttributes) {
        TypeReference type = a.AttributeType;
        if (type.Name == "DynamicAttribute" && type.Namespace == "System.Runtime.CompilerServices") {
          if (a.ConstructorArguments.Count == 1) {
            CustomAttributeArgument[] values = a.ConstructorArguments[0].Value as CustomAttributeArgument[];
            if (values != null && typeIndex < values.Length && values[typeIndex].Value is bool)
              return (bool)values[typeIndex].Value;
          }
          return true;
        }
      }
      return false;
    }
    #endregion
    
    #region Read Attributes
    #region Assembly Attributes
    static readonly ITypeReference assemblyVersionAttributeTypeRef = typeof(System.Reflection.AssemblyVersionAttribute).ToTypeReference();
    
    void AddAttributes(AssemblyDefinition assembly, IList<IUnresolvedAttribute> outputList)
    {
      if (assembly.HasCustomAttributes) {
        AddCustomAttributes(assembly.CustomAttributes, outputList);
      }
      if (assembly.HasSecurityDeclarations) {
        AddSecurityAttributes(assembly.SecurityDeclarations, outputList);
      }
      
      // AssemblyVersionAttribute
      if (assembly.Name.Version != null) {
        var assemblyVersion = new DefaultUnresolvedAttribute(assemblyVersionAttributeTypeRef, new[] { KnownTypeReference.String });
        assemblyVersion.PositionalArguments.Add(CreateSimpleConstantValue(KnownTypeReference.String, assembly.Name.Version.ToString()));
        outputList.Add(interningProvider.Intern(assemblyVersion));
      }
    }
    
    IConstantValue CreateSimpleConstantValue(ITypeReference type, object value)
    {
      return interningProvider.Intern(new SimpleConstantValue(type, interningProvider.InternValue(value)));
    }
    #endregion
    
    #region Module Attributes
    void AddAttributes(ModuleDefinition module, IList<IUnresolvedAttribute> outputList)
    {
      if (module.HasCustomAttributes) {
        AddCustomAttributes(module.CustomAttributes, outputList);
      }
    }
    #endregion
    
    #region Parameter Attributes
    static readonly IUnresolvedAttribute inAttribute = new DefaultUnresolvedAttribute(typeof(InAttribute).ToTypeReference());
    static readonly IUnresolvedAttribute outAttribute = new DefaultUnresolvedAttribute(typeof(OutAttribute).ToTypeReference());
    
    void AddAttributes(ParameterDefinition parameter, DefaultUnresolvedParameter targetParameter)
    {
      if (!targetParameter.IsOut) {
        if (parameter.IsIn)
          targetParameter.Attributes.Add(inAttribute);
        if (parameter.IsOut)
          targetParameter.Attributes.Add(outAttribute);
      }
      if (parameter.HasCustomAttributes) {
        AddCustomAttributes(parameter.CustomAttributes, targetParameter.Attributes);
      }
      if (parameter.HasMarshalInfo) {
        targetParameter.Attributes.Add(ConvertMarshalInfo(parameter.MarshalInfo));
      }
    }
    #endregion
    
    #region Method Attributes
    static readonly ITypeReference dllImportAttributeTypeRef = typeof(DllImportAttribute).ToTypeReference();
    static readonly SimpleConstantValue trueValue = new SimpleConstantValue(KnownTypeReference.Boolean, true);
    static readonly SimpleConstantValue falseValue = new SimpleConstantValue(KnownTypeReference.Boolean, false);
    static readonly ITypeReference callingConventionTypeRef = typeof(CallingConvention).ToTypeReference();
    static readonly IUnresolvedAttribute preserveSigAttribute = new DefaultUnresolvedAttribute(typeof(PreserveSigAttribute).ToTypeReference());
    static readonly ITypeReference methodImplAttributeTypeRef = typeof(MethodImplAttribute).ToTypeReference();
    static readonly ITypeReference methodImplOptionsTypeRef = typeof(MethodImplOptions).ToTypeReference();
    
    static bool HasAnyAttributes(MethodDefinition methodDefinition)
    {
      if (methodDefinition.HasPInvokeInfo)
        return true;
      if ((methodDefinition.ImplAttributes & ~MethodImplAttributes.CodeTypeMask) != 0)
        return true;
      if (methodDefinition.MethodReturnType.HasFieldMarshal)
        return true;
      return methodDefinition.HasCustomAttributes || methodDefinition.MethodReturnType.HasCustomAttributes;
    }
    
    void AddAttributes(MethodDefinition methodDefinition, IList<IUnresolvedAttribute> attributes, IList<IUnresolvedAttribute> returnTypeAttributes)
    {
      MethodImplAttributes implAttributes = methodDefinition.ImplAttributes & ~MethodImplAttributes.CodeTypeMask;
      
      #region DllImportAttribute
      if (methodDefinition.HasPInvokeInfo && methodDefinition.PInvokeInfo != null) {
        PInvokeInfo info = methodDefinition.PInvokeInfo;
        var dllImport = new DefaultUnresolvedAttribute(dllImportAttributeTypeRef, new[] { KnownTypeReference.String });
        dllImport.PositionalArguments.Add(CreateSimpleConstantValue(KnownTypeReference.String, info.Module.Name));
        
        if (info.IsBestFitDisabled)
          dllImport.AddNamedFieldArgument("BestFitMapping", falseValue);
        if (info.IsBestFitEnabled)
          dllImport.AddNamedFieldArgument("BestFitMapping", trueValue);
        
        CallingConvention callingConvention;
        switch (info.Attributes & PInvokeAttributes.CallConvMask) {
          case (PInvokeAttributes)0:
            Debug.WriteLine ("P/Invoke calling convention not set on:" + methodDefinition.FullName);
            callingConvention = 0;
            break;
          case PInvokeAttributes.CallConvCdecl:
            callingConvention = CallingConvention.Cdecl;
            break;
          case PInvokeAttributes.CallConvFastcall:
            callingConvention = CallingConvention.FastCall;
            break;
          case PInvokeAttributes.CallConvStdCall:
            callingConvention = CallingConvention.StdCall;
            break;
          case PInvokeAttributes.CallConvThiscall:
            callingConvention = CallingConvention.ThisCall;
            break;
          case PInvokeAttributes.CallConvWinapi:
            callingConvention = CallingConvention.Winapi;
            break;
          default:
            throw new NotSupportedException("unknown calling convention");
        }
        if (callingConvention != CallingConvention.Winapi)
          dllImport.AddNamedFieldArgument("CallingConvention", CreateSimpleConstantValue(callingConventionTypeRef, (int)callingConvention));
        
        CharSet charSet = CharSet.None;
        switch (info.Attributes & PInvokeAttributes.CharSetMask) {
          case PInvokeAttributes.CharSetAnsi:
            charSet = CharSet.Ansi;
            break;
          case PInvokeAttributes.CharSetAuto:
            charSet = CharSet.Auto;
            break;
          case PInvokeAttributes.CharSetUnicode:
            charSet = CharSet.Unicode;
            break;
        }
        if (charSet != CharSet.None)
          dllImport.AddNamedFieldArgument("CharSet", CreateSimpleConstantValue(charSetTypeRef, (int)charSet));
        
        if (!string.IsNullOrEmpty(info.EntryPoint) && info.EntryPoint != methodDefinition.Name)
          dllImport.AddNamedFieldArgument("EntryPoint", CreateSimpleConstantValue(KnownTypeReference.String, info.EntryPoint));
        
        if (info.IsNoMangle)
          dllImport.AddNamedFieldArgument("ExactSpelling", trueValue);
        
        if ((implAttributes & MethodImplAttributes.PreserveSig) == MethodImplAttributes.PreserveSig)
          implAttributes &= ~MethodImplAttributes.PreserveSig;
        else
          dllImport.AddNamedFieldArgument("PreserveSig", falseValue);
        
        if (info.SupportsLastError)
          dllImport.AddNamedFieldArgument("SetLastError", trueValue);
        
        if (info.IsThrowOnUnmappableCharDisabled)
          dllImport.AddNamedFieldArgument("ThrowOnUnmappableChar", falseValue);
        if (info.IsThrowOnUnmappableCharEnabled)
          dllImport.AddNamedFieldArgument("ThrowOnUnmappableChar", trueValue);
        
        attributes.Add(interningProvider.Intern(dllImport));
      }
      #endregion
      
      #region PreserveSigAttribute
      if (implAttributes == MethodImplAttributes.PreserveSig) {
        attributes.Add(preserveSigAttribute);
        implAttributes = 0;
      }
      #endregion
      
      #region MethodImplAttribute
      if (implAttributes != 0) {
        var methodImpl = new DefaultUnresolvedAttribute(methodImplAttributeTypeRef, new[] { methodImplOptionsTypeRef });
        methodImpl.PositionalArguments.Add(CreateSimpleConstantValue(methodImplOptionsTypeRef, (int)implAttributes));
        attributes.Add(interningProvider.Intern(methodImpl));
      }
      #endregion
      
      if (methodDefinition.HasCustomAttributes) {
        AddCustomAttributes(methodDefinition.CustomAttributes, attributes);
      }
      if (methodDefinition.HasSecurityDeclarations) {
        AddSecurityAttributes(methodDefinition.SecurityDeclarations, attributes);
      }
      if (methodDefinition.MethodReturnType.HasMarshalInfo) {
        returnTypeAttributes.Add(ConvertMarshalInfo(methodDefinition.MethodReturnType.MarshalInfo));
      }
      if (methodDefinition.MethodReturnType.HasCustomAttributes) {
        AddCustomAttributes(methodDefinition.MethodReturnType.CustomAttributes, returnTypeAttributes);
      }
    }
    #endregion
    
    #region Type Attributes
    static readonly DefaultUnresolvedAttribute serializableAttribute = new DefaultUnresolvedAttribute(typeof(SerializableAttribute).ToTypeReference());
    static readonly DefaultUnresolvedAttribute comImportAttribute = new DefaultUnresolvedAttribute(typeof(ComImportAttribute).ToTypeReference());
    static readonly ITypeReference structLayoutAttributeTypeRef = typeof(StructLayoutAttribute).ToTypeReference();
    static readonly ITypeReference layoutKindTypeRef = typeof(LayoutKind).ToTypeReference();
    static readonly ITypeReference charSetTypeRef = typeof(CharSet).ToTypeReference();
    
    void AddAttributes(TypeDefinition typeDefinition, IUnresolvedTypeDefinition targetEntity)
    {
      // SerializableAttribute
      if (typeDefinition.IsSerializable)
        targetEntity.Attributes.Add(serializableAttribute);
      
      // ComImportAttribute
      if (typeDefinition.IsImport)
        targetEntity.Attributes.Add(comImportAttribute);
      
      #region StructLayoutAttribute
      LayoutKind layoutKind = LayoutKind.Auto;
      switch (typeDefinition.Attributes & TypeAttributes.LayoutMask) {
        case TypeAttributes.SequentialLayout:
          layoutKind = LayoutKind.Sequential;
          break;
        case TypeAttributes.ExplicitLayout:
          layoutKind = LayoutKind.Explicit;
          break;
      }
      CharSet charSet = CharSet.None;
      switch (typeDefinition.Attributes & TypeAttributes.StringFormatMask) {
        case TypeAttributes.AnsiClass:
          charSet = CharSet.Ansi;
          break;
        case TypeAttributes.AutoClass:
          charSet = CharSet.Auto;
          break;
        case TypeAttributes.UnicodeClass:
          charSet = CharSet.Unicode;
          break;
      }
      LayoutKind defaultLayoutKind = (typeDefinition.IsValueType && !typeDefinition.IsEnum) ? LayoutKind.Sequential: LayoutKind.Auto;
      if (layoutKind != defaultLayoutKind || charSet != CharSet.Ansi || typeDefinition.PackingSize > 0 || typeDefinition.ClassSize > 0) {
        DefaultUnresolvedAttribute structLayout = new DefaultUnresolvedAttribute(structLayoutAttributeTypeRef, new[] { layoutKindTypeRef });
        structLayout.PositionalArguments.Add(CreateSimpleConstantValue(layoutKindTypeRef, (int)layoutKind));
        if (charSet != CharSet.Ansi) {
          structLayout.AddNamedFieldArgument("CharSet", CreateSimpleConstantValue(charSetTypeRef, (int)charSet));
        }
        if (typeDefinition.PackingSize > 0) {
          structLayout.AddNamedFieldArgument("Pack", CreateSimpleConstantValue(KnownTypeReference.Int32, (int)typeDefinition.PackingSize));
        }
        if (typeDefinition.ClassSize > 0) {
          structLayout.AddNamedFieldArgument("Size", CreateSimpleConstantValue(KnownTypeReference.Int32, (int)typeDefinition.ClassSize));
        }
        targetEntity.Attributes.Add(interningProvider.Intern(structLayout));
      }
      #endregion
      
      if (typeDefinition.HasCustomAttributes) {
        AddCustomAttributes(typeDefinition.CustomAttributes, targetEntity.Attributes);
      }
      if (typeDefinition.HasSecurityDeclarations) {
        AddSecurityAttributes(typeDefinition.SecurityDeclarations, targetEntity.Attributes);
      }
    }
    #endregion
    
    #region Field Attributes
    static readonly ITypeReference fieldOffsetAttributeTypeRef = typeof(FieldOffsetAttribute).ToTypeReference();
    static readonly IUnresolvedAttribute nonSerializedAttribute = new DefaultUnresolvedAttribute(typeof(NonSerializedAttribute).ToTypeReference());
    
    void AddAttributes(FieldDefinition fieldDefinition, IUnresolvedEntity targetEntity)
    {
      // FieldOffsetAttribute
      if (fieldDefinition.HasLayoutInfo) {
        DefaultUnresolvedAttribute fieldOffset = new DefaultUnresolvedAttribute(fieldOffsetAttributeTypeRef, new[] { KnownTypeReference.Int32 });
        fieldOffset.PositionalArguments.Add(CreateSimpleConstantValue(KnownTypeReference.Int32, fieldDefinition.Offset));
        targetEntity.Attributes.Add(interningProvider.Intern(fieldOffset));
      }
      
      // NonSerializedAttribute
      if (fieldDefinition.IsNotSerialized) {
        targetEntity.Attributes.Add(nonSerializedAttribute);
      }
      
      if (fieldDefinition.HasMarshalInfo) {
        targetEntity.Attributes.Add(ConvertMarshalInfo(fieldDefinition.MarshalInfo));
      }
      
      if (fieldDefinition.HasCustomAttributes) {
        AddCustomAttributes(fieldDefinition.CustomAttributes, targetEntity.Attributes);
      }
    }
    #endregion
    
    #region Event Attributes
    void AddAttributes(EventDefinition eventDefinition, IUnresolvedEntity targetEntity)
    {
      if (eventDefinition.HasCustomAttributes) {
        AddCustomAttributes(eventDefinition.CustomAttributes, targetEntity.Attributes);
      }
    }
    #endregion
    
    #region Property Attributes
    void AddAttributes(PropertyDefinition propertyDefinition, IUnresolvedEntity targetEntity)
    {
      if (propertyDefinition.HasCustomAttributes) {
        AddCustomAttributes(propertyDefinition.CustomAttributes, targetEntity.Attributes);
      }
    }
    #endregion
    
    #region MarshalAsAttribute (ConvertMarshalInfo)
    static readonly ITypeReference marshalAsAttributeTypeRef = typeof(MarshalAsAttribute).ToTypeReference();
    static readonly ITypeReference unmanagedTypeTypeRef = typeof(UnmanagedType).ToTypeReference();
    
    IUnresolvedAttribute ConvertMarshalInfo(MarshalInfo marshalInfo)
    {
      DefaultUnresolvedAttribute attr = new DefaultUnresolvedAttribute(marshalAsAttributeTypeRef, new[] { unmanagedTypeTypeRef });
      attr.PositionalArguments.Add(CreateSimpleConstantValue(unmanagedTypeTypeRef, (int)marshalInfo.NativeType));
      
      FixedArrayMarshalInfo fami = marshalInfo as FixedArrayMarshalInfo;
      if (fami != null) {
        attr.AddNamedFieldArgument("SizeConst", CreateSimpleConstantValue(KnownTypeReference.Int32, (int)fami.Size));
        if (fami.ElementType != NativeType.None)
          attr.AddNamedFieldArgument("ArraySubType", CreateSimpleConstantValue(unmanagedTypeTypeRef, (int)fami.ElementType));
      }
      SafeArrayMarshalInfo sami = marshalInfo as SafeArrayMarshalInfo;
      if (sami != null && sami.ElementType != VariantType.None) {
        attr.AddNamedFieldArgument("SafeArraySubType", CreateSimpleConstantValue(typeof(VarEnum).ToTypeReference(), (int)sami.ElementType));
      }
      ArrayMarshalInfo ami = marshalInfo as ArrayMarshalInfo;
      if (ami != null) {
        if (ami.ElementType != NativeType.Max)
          attr.AddNamedFieldArgument("ArraySubType", CreateSimpleConstantValue(unmanagedTypeTypeRef, (int)ami.ElementType));
        if (ami.Size >= 0)
          attr.AddNamedFieldArgument("SizeConst", CreateSimpleConstantValue(KnownTypeReference.Int32, (int)ami.Size));
        if (ami.SizeParameterMultiplier != 0 && ami.SizeParameterIndex >= 0)
          attr.AddNamedFieldArgument("SizeParamIndex", CreateSimpleConstantValue(KnownTypeReference.Int16, (short)ami.SizeParameterIndex));
      }
      CustomMarshalInfo cmi = marshalInfo as CustomMarshalInfo;
      if (cmi != null) {
        if (cmi.ManagedType != null)
          attr.AddNamedFieldArgument("MarshalType", CreateSimpleConstantValue(KnownTypeReference.String, cmi.ManagedType.FullName));
        if (!string.IsNullOrEmpty(cmi.Cookie))
          attr.AddNamedFieldArgument("MarshalCookie", CreateSimpleConstantValue(KnownTypeReference.String, cmi.Cookie));
      }
      FixedSysStringMarshalInfo fssmi = marshalInfo as FixedSysStringMarshalInfo;
      if (fssmi != null) {
        attr.AddNamedFieldArgument("SizeConst", CreateSimpleConstantValue(KnownTypeReference.Int32, (int)fssmi.Size));
      }
      
      return InterningProvider.Intern(attr);
    }
    #endregion
    
    #region Custom Attributes (ReadAttribute)
    void AddCustomAttributes(Mono.Collections.Generic.Collection<CustomAttribute> attributes, IList<IUnresolvedAttribute> targetCollection)
    {
      foreach (var cecilAttribute in attributes) {
        TypeReference type = cecilAttribute.AttributeType;
        if (type.Namespace == "System.Runtime.CompilerServices") {
          if (type.Name == "DynamicAttribute" || type.Name == "ExtensionAttribute" || type.Name == "DecimalConstantAttribute")
            continue;
        } else if (type.Name == "ParamArrayAttribute" && type.Namespace == "System") {
          continue;
        }
        targetCollection.Add(ReadAttribute(cecilAttribute));
      }
    }
    
    [CLSCompliant(false)]
    public IUnresolvedAttribute ReadAttribute(CustomAttribute attribute)
    {
      if (attribute == null)
        throw new ArgumentNullException("attribute");
      MethodReference ctor = attribute.Constructor;
      ITypeReference attributeType = ReadTypeReference(attribute.AttributeType);
      IList<ITypeReference> ctorParameterTypes = EmptyList<ITypeReference>.Instance;
      if (ctor.HasParameters) {
        ctorParameterTypes = new ITypeReference[ctor.Parameters.Count];
        for (int i = 0; i < ctorParameterTypes.Count; i++) {
          ctorParameterTypes[i] = ReadTypeReference(ctor.Parameters[i].ParameterType);
        }
        ctorParameterTypes = interningProvider.InternList(ctorParameterTypes);
      }
      return interningProvider.Intern(new UnresolvedAttributeBlob(attributeType, ctorParameterTypes, attribute.GetBlob()));
    }
    #endregion
    
    #region Security Attributes
    /// <summary>
    /// Reads a security declaration.
    /// </summary>
    [CLSCompliant(false)]
    public IList<IUnresolvedAttribute> ReadSecurityDeclaration(SecurityDeclaration secDecl)
    {
      if (secDecl == null)
        throw new ArgumentNullException("secDecl");
      var result = new List<IUnresolvedAttribute>();
      AddSecurityAttributes(secDecl, result);
      return result;
    }
    
    void AddSecurityAttributes(Mono.Collections.Generic.Collection<SecurityDeclaration> securityDeclarations, IList<IUnresolvedAttribute> targetCollection)
    {
      foreach (var secDecl in securityDeclarations) {
        AddSecurityAttributes(secDecl, targetCollection);
      }
    }
    
    void AddSecurityAttributes(SecurityDeclaration secDecl, IList<IUnresolvedAttribute> targetCollection)
    {
      byte[] blob;
      try {
        blob = secDecl.GetBlob();
      } catch (NotSupportedException) {
        return; // https://github.com/icsharpcode/SharpDevelop/issues/284
      }
      var blobSecDecl = new UnresolvedSecurityDeclarationBlob((int)secDecl.Action, blob);
      targetCollection.AddRange(blobSecDecl.UnresolvedAttributes);
    }
    #endregion
    #endregion
    
    #region Read Type Definition
    DefaultUnresolvedTypeDefinition CreateTopLevelTypeDefinition(TypeDefinition typeDefinition)
    {
      string name = ReflectionHelper.SplitTypeParameterCountFromReflectionName(typeDefinition.Name);
      var td = new DefaultUnresolvedTypeDefinition(typeDefinition.Namespace, name);
      if (typeDefinition.HasGenericParameters)
        InitTypeParameters(typeDefinition, td.TypeParameters);
      return td;
    }
    
    static void InitTypeParameters(TypeDefinition typeDefinition, IList<IUnresolvedTypeParameter> typeParameters)
    {
      // Type parameters are initialized within the constructor so that the class can be put into the type storage
      // before the rest of the initialization runs - this allows it to be available for early binding as soon as possible.
      for (int i = 0; i < typeDefinition.GenericParameters.Count; i++) {
        if (typeDefinition.GenericParameters[i].Position != i)
          throw new InvalidOperationException("g.Position != i");
        typeParameters.Add(new DefaultUnresolvedTypeParameter(
          SymbolKind.TypeDefinition, i, typeDefinition.GenericParameters[i].Name));
      }
    }
    
    void InitTypeParameterConstraints(TypeDefinition typeDefinition, IList<IUnresolvedTypeParameter> typeParameters)
    {
      for (int i = 0; i < typeParameters.Count; i++) {
        var tp = (DefaultUnresolvedTypeParameter)typeParameters[i];
        AddConstraints(tp, typeDefinition.GenericParameters[i]);
        tp.ApplyInterningProvider(interningProvider);
      }
    }
    
    void InitTypeDefinition(TypeDefinition typeDefinition, DefaultUnresolvedTypeDefinition td)
    {
      td.Kind = GetTypeKind(typeDefinition);
      InitTypeModifiers(typeDefinition, td);
      InitTypeParameterConstraints(typeDefinition, td.TypeParameters);
      
      // nested types can be initialized only after generic parameters were created
      InitNestedTypes(typeDefinition, td, td.NestedTypes);
      AddAttributes(typeDefinition, td);
      td.HasExtensionMethods = HasExtensionAttribute(typeDefinition);
      
      InitBaseTypes(typeDefinition, td.BaseTypes);
      
      td.AddDefaultConstructorIfRequired = (td.Kind == TypeKind.Struct || td.Kind == TypeKind.Enum);
      InitMembers(typeDefinition, td, td.Members);
      td.ApplyInterningProvider(interningProvider);
      td.Freeze();
      RegisterCecilObject(td, typeDefinition);
    }
    
    void InitBaseTypes(TypeDefinition typeDefinition, IList<ITypeReference> baseTypes)
    {
      // set base classes
      if (typeDefinition.IsEnum) {
        foreach (FieldDefinition enumField in typeDefinition.Fields) {
          if (!enumField.IsStatic) {
            baseTypes.Add(ReadTypeReference(enumField.FieldType));
            break;
          }
        }
      } else {
        if (typeDefinition.BaseType != null) {
          baseTypes.Add(ReadTypeReference(typeDefinition.BaseType));
        }
        if (typeDefinition.HasInterfaces) {
          foreach (TypeReference iface in typeDefinition.Interfaces) {
            baseTypes.Add(ReadTypeReference(iface));
          }
        }
      }
    }
    
    void InitNestedTypes(TypeDefinition typeDefinition, IUnresolvedTypeDefinition declaringTypeDefinition, IList<IUnresolvedTypeDefinition> nestedTypes)
    {
      if (!typeDefinition.HasNestedTypes)
        return;
      foreach (TypeDefinition nestedTypeDef in typeDefinition.NestedTypes) {
        TypeAttributes visibility = nestedTypeDef.Attributes & TypeAttributes.VisibilityMask;
        if (this.IncludeInternalMembers
            || visibility == TypeAttributes.NestedPublic
            || visibility == TypeAttributes.NestedFamily
            || visibility == TypeAttributes.NestedFamORAssem)
        {
          string name = nestedTypeDef.Name;
          int pos = name.LastIndexOf('/');
          if (pos > 0)
            name = name.Substring(pos + 1);
          name = ReflectionHelper.SplitTypeParameterCountFromReflectionName(name);
          var nestedType = new DefaultUnresolvedTypeDefinition(declaringTypeDefinition, name);
          InitTypeParameters(nestedTypeDef, nestedType.TypeParameters);
          nestedTypes.Add(nestedType);
          InitTypeDefinition(nestedTypeDef, nestedType);
        }
      }
    }
    
    static TypeKind GetTypeKind(TypeDefinition typeDefinition)
    {
      // set classtype
      if (typeDefinition.IsInterface) {
        return TypeKind.Interface;
      } else if (typeDefinition.IsEnum) {
        return TypeKind.Enum;
      } else if (typeDefinition.IsValueType) {
        return TypeKind.Struct;
      } else if (IsDelegate(typeDefinition)) {
        return TypeKind.Delegate;
      } else if (IsModule(typeDefinition)) {
        return TypeKind.Module;
      } else {
        return TypeKind.Class;
      }
    }
    
    static void InitTypeModifiers(TypeDefinition typeDefinition, AbstractUnresolvedEntity td)
    {
      td.IsSealed = typeDefinition.IsSealed;
      td.IsAbstract = typeDefinition.IsAbstract;
      switch (typeDefinition.Attributes & TypeAttributes.VisibilityMask) {
        case TypeAttributes.NotPublic:
        case TypeAttributes.NestedAssembly:
          td.Accessibility = Accessibility.Internal;
          break;
        case TypeAttributes.Public:
        case TypeAttributes.NestedPublic:
          td.Accessibility = Accessibility.Public;
          break;
        case TypeAttributes.NestedPrivate:
          td.Accessibility = Accessibility.Private;
          break;
        case TypeAttributes.NestedFamily:
          td.Accessibility = Accessibility.Protected;
          break;
        case TypeAttributes.NestedFamANDAssem:
          td.Accessibility = Accessibility.ProtectedAndInternal;
          break;
        case TypeAttributes.NestedFamORAssem:
          td.Accessibility = Accessibility.ProtectedOrInternal;
          break;
      }
    }
    
    static bool IsDelegate(TypeDefinition type)
    {
      if (type.BaseType != null && type.BaseType.Namespace == "System") {
        if (type.BaseType.Name == "MulticastDelegate")
          return true;
        if (type.BaseType.Name == "Delegate" && type.Name != "MulticastDelegate")
          return true;
      }
      return false;
    }
    
    static bool IsModule(TypeDefinition type)
    {
      if (!type.HasCustomAttributes)
        return false;
      foreach (var att in type.CustomAttributes) {
        if (att.AttributeType.FullName == "Microsoft.VisualBasic.CompilerServices.StandardModuleAttribute"
            || att.AttributeType.FullName == "System.Runtime.CompilerServices.CompilerGlobalScopeAttribute")
        {
          return true;
        }
      }
      return false;
    }
    
    void InitMembers(TypeDefinition typeDefinition, IUnresolvedTypeDefinition td, IList<IUnresolvedMember> members)
    {
      if (typeDefinition.HasMethods) {
        foreach (MethodDefinition method in typeDefinition.Methods) {
          if (IsVisible(method.Attributes) && !IsAccessor(method.SemanticsAttributes)) {
            SymbolKind type = SymbolKind.Method;
            if (method.IsSpecialName) {
              if (method.IsConstructor)
                type = SymbolKind.Constructor;
              else if (method.Name.StartsWith("op_", StringComparison.Ordinal))
                type = SymbolKind.Operator;
            }
            members.Add(ReadMethod(method, td, type));
          }
        }
      }
      if (typeDefinition.HasFields) {
        foreach (FieldDefinition field in typeDefinition.Fields) {
          if (IsVisible(field.Attributes) && !field.IsSpecialName) {
            members.Add(ReadField(field, td));
          }
        }
      }
      if (typeDefinition.HasProperties) {
        string defaultMemberName = null;
        var defaultMemberAttribute = typeDefinition.CustomAttributes.FirstOrDefault(
          a => a.AttributeType.FullName == typeof(System.Reflection.DefaultMemberAttribute).FullName);
        if (defaultMemberAttribute != null && defaultMemberAttribute.ConstructorArguments.Count == 1) {
          defaultMemberName = defaultMemberAttribute.ConstructorArguments[0].Value as string;
        }
        foreach (PropertyDefinition property in typeDefinition.Properties) {
          bool getterVisible = property.GetMethod != null && IsVisible(property.GetMethod.Attributes);
          bool setterVisible = property.SetMethod != null && IsVisible(property.SetMethod.Attributes);
          if (getterVisible || setterVisible) {
            SymbolKind type = SymbolKind.Property;
            if (property.HasParameters) {
              // Try to detect indexer:
              if (property.Name == defaultMemberName) {
                type = SymbolKind.Indexer; // normal indexer
              } else if (property.Name.EndsWith(".Item", StringComparison.Ordinal) && (property.GetMethod ?? property.SetMethod).HasOverrides) {
                // explicit interface implementation of indexer
                type = SymbolKind.Indexer;
                // We can't really tell parameterized properties and indexers apart in this case without
                // resolving the interface, so we rely on the "Item" naming convention instead.
              }
            }
            members.Add(ReadProperty(property, td, type));
          }
        }
      }
      if (typeDefinition.HasEvents) {
        foreach (EventDefinition ev in typeDefinition.Events) {
          if (ev.AddMethod != null && IsVisible(ev.AddMethod.Attributes)) {
            members.Add(ReadEvent(ev, td));
          }
        }
      }
    }
    
    static bool IsAccessor(MethodSemanticsAttributes semantics)
    {
      return !(semantics == MethodSemanticsAttributes.None || semantics == MethodSemanticsAttributes.Other);
    }
    #endregion
    
    #region Lazy-Loaded Type Definition
    /// <summary>
    /// Given an assembly that was created by the CecilLoader with lazy-loading enabled,
    /// this method will eagerly load all classes, and free any references to the source Cecil objects.
    /// 
    /// The intended usage pattern for this method is:
    /// 1. use lazy-loading to improve the latency when new assemblies have to be loaded
    /// 2. later, when the CPU is idle, call FinishLazyLoading() to free up the memory consumed by the Cecil objects
    /// </summary>
    public static void FinishLazyLoading(IUnresolvedAssembly assembly)
    {
      if (assembly == null)
        throw new ArgumentNullException("assembly");
      foreach (var type in assembly.TopLevelTypeDefinitions) {
        var lctd = type as LazyCecilTypeDefinition;
        if (lctd != null)
          lctd.InitAndReleaseReferences();
      }
    }
    
    sealed class LazyCecilTypeDefinition : AbstractUnresolvedEntity, IUnresolvedTypeDefinition
    {
      // loader + cecilTypeDef, used for lazy-loading; and set to null after lazy loading is complete
      CecilLoader loader;
      TypeDefinition cecilTypeDef;
      
      readonly string namespaceName;
      readonly TypeKind kind;
      readonly IList<IUnresolvedTypeParameter> typeParameters;
      
      // lazy-loaded fields
      IList<ITypeReference> baseTypes;
      IList<IUnresolvedTypeDefinition> nestedTypes;
      IList<IUnresolvedMember> members;
      
      public LazyCecilTypeDefinition(CecilLoader loader, TypeDefinition typeDefinition)
      {
        this.loader = loader;
        this.cecilTypeDef = typeDefinition;
        this.SymbolKind = SymbolKind.TypeDefinition;
        this.namespaceName = typeDefinition.Namespace;
        this.Name = ReflectionHelper.SplitTypeParameterCountFromReflectionName(typeDefinition.Name);
        var tps = new List<IUnresolvedTypeParameter>();
        InitTypeParameters(typeDefinition, tps);
        this.typeParameters = FreezableHelper.FreezeList(tps);
        
        this.kind = GetTypeKind(typeDefinition);
        InitTypeModifiers(typeDefinition, this);
        loader.InitTypeParameterConstraints(typeDefinition, typeParameters);
        
        loader.AddAttributes(typeDefinition, this);
        flags[FlagHasExtensionMethods] = HasExtensionAttribute(typeDefinition);
        
        this.ApplyInterningProvider(loader.interningProvider);
        this.Freeze();
      }
      
      public override string Namespace {
        get { return namespaceName; }
        set { throw new NotSupportedException(); }
      }
      
      public override string ReflectionName {
        get { return this.FullTypeName.ReflectionName; }
      }
      
      public FullTypeName FullTypeName {
        get {
          return new TopLevelTypeName(namespaceName, this.Name, typeParameters.Count);
        }
      }
      
      public TypeKind Kind {
        get { return kind; }
      }
      
      public IList<IUnresolvedTypeParameter> TypeParameters {
        get { return typeParameters; }
      }
      
      public IList<ITypeReference> BaseTypes {
        get {
          var result = LazyInit.VolatileRead(ref this.baseTypes);
          if (result != null) {
            return result;
          } else {
            return LazyInit.GetOrSet(ref this.baseTypes, TryInitBaseTypes());
          }
        }
      }
      
      IList<ITypeReference> TryInitBaseTypes()
      {
        var loader = LazyInit.VolatileRead(ref this.loader);
        var cecilTypeDef = LazyInit.VolatileRead(ref this.cecilTypeDef);
        if (loader == null || cecilTypeDef == null) {
          // Cannot initialize because the references to loader/cecilTypeDef
          // have already been cleared.
          // This can only happen if the class was loaded by another thread concurrently to the TryInitBaseTypes() call,
          // so the GetOrSet() call in the property will retrieve the value set by the other thread.
          return null;
        }
        lock (loader.currentModule) {
          var result = new List<ITypeReference>();
          loader.InitBaseTypes(cecilTypeDef, result);
          return FreezableHelper.FreezeList(result);
        }
      }
      
      public IList<IUnresolvedTypeDefinition> NestedTypes {
        get {
          var result = LazyInit.VolatileRead(ref this.nestedTypes);
          if (result != null) {
            return result;
          } else {
            return LazyInit.GetOrSet(ref this.nestedTypes, TryInitNestedTypes());
          }
        }
      }
      
      IList<IUnresolvedTypeDefinition> TryInitNestedTypes()
      {
        var loader = LazyInit.VolatileRead(ref this.loader);
        var cecilTypeDef = LazyInit.VolatileRead(ref this.cecilTypeDef);
        if (loader == null || cecilTypeDef == null) {
          // Cannot initialize because the references to loader/cecilTypeDef
          // have already been cleared.
          // This can only happen if the class was loaded by another thread concurrently to the TryInitNestedTypes() call,
          // so the GetOrSet() call in the property will retrieve the value set by the other thread.
          return null;
        }
        lock (loader.currentModule) {
          var result = new List<IUnresolvedTypeDefinition>();
          loader.InitNestedTypes(cecilTypeDef, this, result);
          return FreezableHelper.FreezeList(result);
        }
      }
      
      public IList<IUnresolvedMember> Members {
        get {
          var result = LazyInit.VolatileRead(ref this.members);
          if (result != null) {
            return result;
          } else {
            return LazyInit.GetOrSet(ref this.members, TryInitMembers());
          }
        }
      }
      
      IList<IUnresolvedMember> TryInitMembers()
      {
        var loader = LazyInit.VolatileRead(ref this.loader);
        var cecilTypeDef = LazyInit.VolatileRead(ref this.cecilTypeDef);
        if (loader == null || cecilTypeDef == null) {
          // Cannot initialize because the references to loader/cecilTypeDef
          // have already been cleared.
          // This can only happen if the class was loaded by another thread concurrently to the TryInitMembers() call,
          // so the GetOrSet() call in the property will retrieve the value set by the other thread.
          return null;
        }
        lock (loader.currentModule) {
          if (this.members != null)
            return this.members;
          var result = new List<IUnresolvedMember>();
          loader.InitMembers(cecilTypeDef, this, result);
          return FreezableHelper.FreezeList(result);
        }
      }
      
      public void InitAndReleaseReferences()
      {
        if (LazyInit.VolatileRead(ref this.baseTypes) == null)
          LazyInit.GetOrSet(ref this.baseTypes, TryInitBaseTypes());
        if (LazyInit.VolatileRead(ref this.nestedTypes) == null)
          LazyInit.GetOrSet(ref this.nestedTypes, TryInitNestedTypes());
        if (LazyInit.VolatileRead(ref this.members) == null)
          LazyInit.GetOrSet(ref this.members, TryInitMembers());
        Thread.MemoryBarrier(); // commit lazily-initialized fields to memory before nulling out the references
        // Allow the GC to collect the cecil type definition
        loader = null;
        cecilTypeDef = null;
      }
      
      public IEnumerable<IUnresolvedMethod> Methods {
        get { return Members.OfType<IUnresolvedMethod>(); }
      }
      
      public IEnumerable<IUnresolvedProperty> Properties {
        get { return Members.OfType<IUnresolvedProperty>(); }
      }
      
      public IEnumerable<IUnresolvedField> Fields {
        get { return Members.OfType<IUnresolvedField>(); }
      }
      
      public IEnumerable<IUnresolvedEvent> Events {
        get { return Members.OfType<IUnresolvedEvent>(); }
      }
      
      public bool AddDefaultConstructorIfRequired {
        get { return kind == TypeKind.Struct || kind == TypeKind.Enum; }
      }
      
      public bool? HasExtensionMethods {
        get { return flags[FlagHasExtensionMethods]; }
        // we always return true or false, never null.
        // FlagHasNoExtensionMethods is unused in LazyCecilTypeDefinition
      }
      
      public bool IsPartial {
        get { return false; }
      }
      
      public override object Clone()
      {
        throw new NotSupportedException();
      }
      
      public IType Resolve(ITypeResolveContext context)
      {
        if (context == null)
          throw new ArgumentNullException("context");
        if (context.CurrentAssembly == null)
          throw new ArgumentException("An ITypeDefinition cannot be resolved in a context without a current assembly.");
        return context.CurrentAssembly.GetTypeDefinition(this.FullTypeName)
          ?? (IType)new UnknownType(this.Namespace, this.Name, this.TypeParameters.Count);
      }
      
      public ITypeResolveContext CreateResolveContext(ITypeResolveContext parentContext)
      {
        return parentContext;
      }
    }
    #endregion
    
    #region Read Method
    [CLSCompliant(false)]
    public IUnresolvedMethod ReadMethod(MethodDefinition method, IUnresolvedTypeDefinition parentType, SymbolKind methodType = SymbolKind.Method)
    {
      return ReadMethod(method, parentType, methodType, null);
    }
    
    IUnresolvedMethod ReadMethod(MethodDefinition method, IUnresolvedTypeDefinition parentType, SymbolKind methodType, IUnresolvedMember accessorOwner)
    {
      if (method == null)
        return null;
      DefaultUnresolvedMethod m = new DefaultUnresolvedMethod(parentType, method.Name);
      m.SymbolKind = methodType;
      m.AccessorOwner = accessorOwner;
      m.HasBody = method.HasBody;
      if (method.HasGenericParameters) {
        for (int i = 0; i < method.GenericParameters.Count; i++) {
          if (method.GenericParameters[i].Position != i)
            throw new InvalidOperationException("g.Position != i");
          m.TypeParameters.Add(new DefaultUnresolvedTypeParameter(
            SymbolKind.Method, i, method.GenericParameters[i].Name));
        }
        for (int i = 0; i < method.GenericParameters.Count; i++) {
          var tp = (DefaultUnresolvedTypeParameter)m.TypeParameters[i];
          AddConstraints(tp, method.GenericParameters[i]);
          tp.ApplyInterningProvider(interningProvider);
        }
      }
      
      m.ReturnType = ReadTypeReference(method.ReturnType, typeAttributes: method.MethodReturnType);
      
      if (HasAnyAttributes(method))
        AddAttributes(method, m.Attributes, m.ReturnTypeAttributes);
      TranslateModifiers(method, m);
      
      if (method.HasParameters) {
        foreach (ParameterDefinition p in method.Parameters) {
          m.Parameters.Add(ReadParameter(p));
        }
      }
      
      // mark as extension method if the attribute is set
      if (method.IsStatic && HasExtensionAttribute(method)) {
        m.IsExtensionMethod = true;
      }

      int lastDot = method.Name.LastIndexOf('.');
      if (lastDot >= 0 && method.HasOverrides) {
        // To be consistent with the parser-initialized type system, shorten the method name:
        m.Name = method.Name.Substring(lastDot + 1);
        m.IsExplicitInterfaceImplementation = true;
        foreach (var or in method.Overrides) {
          m.ExplicitInterfaceImplementations.Add(new DefaultMemberReference(
            accessorOwner != null ? SymbolKind.Accessor : SymbolKind.Method,
            ReadTypeReference(or.DeclaringType),
            or.Name, or.GenericParameters.Count, m.Parameters.Select(p => p.Type).ToList()));
        }
      }

      FinishReadMember(m, method);
      return m;
    }
    
    static bool HasExtensionAttribute(ICustomAttributeProvider provider)
    {
      if (provider.HasCustomAttributes) {
        foreach (var attr in provider.CustomAttributes) {
          if (attr.AttributeType.Name == "ExtensionAttribute" && attr.AttributeType.Namespace == "System.Runtime.CompilerServices")
            return true;
        }
      }
      return false;
    }
    
    bool IsVisible(MethodAttributes att)
    {
      att &= MethodAttributes.MemberAccessMask;
      return IncludeInternalMembers
        || att == MethodAttributes.Public
        || att == MethodAttributes.Family
        || att == MethodAttributes.FamORAssem;
    }
    
    static Accessibility GetAccessibility(MethodAttributes attr)
    {
      switch (attr & MethodAttributes.MemberAccessMask) {
        case MethodAttributes.Public:
          return Accessibility.Public;
        case MethodAttributes.FamANDAssem:
          return Accessibility.ProtectedAndInternal;
        case MethodAttributes.Assembly:
          return Accessibility.Internal;
        case MethodAttributes.Family:
          return Accessibility.Protected;
        case MethodAttributes.FamORAssem:
          return Accessibility.ProtectedOrInternal;
        default:
          return Accessibility.Private;
      }
    }
    
    void TranslateModifiers(MethodDefinition method, AbstractUnresolvedMember m)
    {
      if (m.DeclaringTypeDefinition.Kind == TypeKind.Interface) {
        // interface members don't have modifiers, but we want to handle them as "public abstract"
        m.Accessibility = Accessibility.Public;
        m.IsAbstract = true;
      } else {
        m.Accessibility = GetAccessibility(method.Attributes);
        if (method.IsAbstract) {
          m.IsAbstract = true;
          m.IsOverride = !method.IsNewSlot;
        } else if (method.IsFinal) {
          if (!method.IsNewSlot) {
            m.IsSealed = true;
            m.IsOverride = true;
          }
        } else if (method.IsVirtual) {
          if (method.IsNewSlot)
            m.IsVirtual = true;
          else
            m.IsOverride = true;
        }
        m.IsStatic = method.IsStatic;
      }
    }
    #endregion
    
    #region Read Parameter
    [CLSCompliant(false)]
    public IUnresolvedParameter ReadParameter(ParameterDefinition parameter)
    {
      if (parameter == null)
        throw new ArgumentNullException("parameter");
      var type = ReadTypeReference(parameter.ParameterType, typeAttributes: parameter);
      var p = new DefaultUnresolvedParameter(type, interningProvider.Intern(parameter.Name));
      
      if (parameter.ParameterType is Mono.Cecil.ByReferenceType) {
        if (!parameter.IsIn && parameter.IsOut)
          p.IsOut = true;
        else
          p.IsRef = true;
      }
      AddAttributes(parameter, p);
      
      if (parameter.IsOptional) {
        p.DefaultValue = CreateSimpleConstantValue(type, parameter.Constant);
      }
      
      if (parameter.ParameterType is Mono.Cecil.ArrayType) {
        foreach (CustomAttribute att in parameter.CustomAttributes) {
          if (att.AttributeType.FullName == typeof(ParamArrayAttribute).FullName) {
            p.IsParams = true;
            break;
          }
        }
      }
      
      return interningProvider.Intern(p);
    }
    #endregion
    
    #region Read Field
    bool IsVisible(FieldAttributes att)
    {
      att &= FieldAttributes.FieldAccessMask;
      return IncludeInternalMembers
        || att == FieldAttributes.Public
        || att == FieldAttributes.Family
        || att == FieldAttributes.FamORAssem;
    }

    decimal? TryDecodeDecimalConstantAttribute(CustomAttribute attribute)
    {
      if (attribute.ConstructorArguments.Count != 5)
        return null;

      BlobReader reader = new BlobReader(attribute.GetBlob(), null);
      if (reader.ReadUInt16() != 0x0001) {
        Debug.WriteLine("Unknown blob prolog");
        return null;
      }

      // DecimalConstantAttribute has the arguments (byte scale, byte sign, uint hi, uint mid, uint low) or (byte scale, byte sign, int hi, int mid, int low)
      // Both of these invoke the Decimal constructor (int lo, int mid, int hi, bool isNegative, byte scale) with explicit argument conversions if required.
      var ctorArgs = new object[attribute.ConstructorArguments.Count];
      for (int i = 0; i < ctorArgs.Length; i++) {
        switch (attribute.ConstructorArguments[i].Type.FullName) {
          case "System.Byte":
            ctorArgs[i] = reader.ReadByte();
            break;
          case "System.Int32":
            ctorArgs[i] = reader.ReadInt32();
            break;
          case "System.UInt32":
            ctorArgs[i] = unchecked((int)reader.ReadUInt32());
            break;
          default:
            return null;
        }
      }

      if (!ctorArgs.Select(a => a.GetType()).SequenceEqual(new[] { typeof(byte), typeof(byte), typeof(int), typeof(int), typeof(int) }))
        return null;

      return new decimal((int)ctorArgs[4], (int)ctorArgs[3], (int)ctorArgs[2], (byte)ctorArgs[1] != 0, (byte)ctorArgs[0]);
    }
    
    [CLSCompliant(false)]
    public IUnresolvedField ReadField(FieldDefinition field, IUnresolvedTypeDefinition parentType)
    {
      if (field == null)
        throw new ArgumentNullException("field");
      if (parentType == null)
        throw new ArgumentNullException("parentType");
      
      DefaultUnresolvedField f = new DefaultUnresolvedField(parentType, field.Name);
      f.Accessibility = GetAccessibility(field.Attributes);
      f.IsReadOnly = field.IsInitOnly;
      f.IsStatic = field.IsStatic;
      f.ReturnType = ReadTypeReference(field.FieldType, typeAttributes: field);
      if (field.HasConstant) {
        f.ConstantValue = CreateSimpleConstantValue(f.ReturnType, field.Constant);
      }
      else {
        var decConstant = field.CustomAttributes.FirstOrDefault(a => a.AttributeType.FullName == "System.Runtime.CompilerServices.DecimalConstantAttribute");
        if (decConstant != null) {
          var constValue = TryDecodeDecimalConstantAttribute(decConstant);
          if (constValue != null)
            f.ConstantValue = CreateSimpleConstantValue(f.ReturnType, constValue);
        }
      }
      AddAttributes(field, f);
      
      RequiredModifierType modreq = field.FieldType as RequiredModifierType;
      if (modreq != null && modreq.ModifierType.FullName == typeof(IsVolatile).FullName) {
        f.IsVolatile = true;
      }
      
      FinishReadMember(f, field);
      return f;
    }
    
    static Accessibility GetAccessibility(FieldAttributes attr)
    {
      switch (attr & FieldAttributes.FieldAccessMask) {
        case FieldAttributes.Public:
          return Accessibility.Public;
        case FieldAttributes.FamANDAssem:
          return Accessibility.ProtectedAndInternal;
        case FieldAttributes.Assembly:
          return Accessibility.Internal;
        case FieldAttributes.Family:
          return Accessibility.Protected;
        case FieldAttributes.FamORAssem:
          return Accessibility.ProtectedOrInternal;
        default:
          return Accessibility.Private;
      }
    }
    #endregion
    
    #region Type Parameter Constraints
    void AddConstraints(DefaultUnresolvedTypeParameter tp, GenericParameter g)
    {
      switch (g.Attributes & GenericParameterAttributes.VarianceMask) {
        case GenericParameterAttributes.Contravariant:
          tp.Variance = VarianceModifier.Contravariant;
          break;
        case GenericParameterAttributes.Covariant:
          tp.Variance = VarianceModifier.Covariant;
          break;
      }
      
      tp.HasReferenceTypeConstraint = g.HasReferenceTypeConstraint;
      tp.HasValueTypeConstraint = g.HasNotNullableValueTypeConstraint;
      tp.HasDefaultConstructorConstraint = g.HasDefaultConstructorConstraint;
      
      if (g.HasConstraints) {
        foreach (TypeReference constraint in g.Constraints) {
          tp.Constraints.Add(ReadTypeReference(constraint));
        }
      }
    }
    #endregion
    
    #region Read Property

    Accessibility MergePropertyAccessibility (Accessibility left, Accessibility right)
    {
      if (left == Accessibility.Public || right == Accessibility.Public)
        return Accessibility.Public;

      if (left == Accessibility.ProtectedOrInternal || right == Accessibility.ProtectedOrInternal)
        return Accessibility.ProtectedOrInternal;

      if (left == Accessibility.Protected && right == Accessibility.Internal ||
          left == Accessibility.Internal && right == Accessibility.Protected)
        return Accessibility.ProtectedOrInternal;

      if (left == Accessibility.Protected || right == Accessibility.Protected)
        return Accessibility.Protected;

      if (left == Accessibility.Internal || right == Accessibility.Internal)
        return Accessibility.Internal;

      if (left == Accessibility.ProtectedAndInternal || right == Accessibility.ProtectedAndInternal)
        return Accessibility.ProtectedAndInternal;

      return left;
    }

    [CLSCompliant(false)]
    public IUnresolvedProperty ReadProperty(PropertyDefinition property, IUnresolvedTypeDefinition parentType, SymbolKind propertyType = SymbolKind.Property)
    {
      if (property == null)
        throw new ArgumentNullException("property");
      if (parentType == null)
        throw new ArgumentNullException("parentType");
      DefaultUnresolvedProperty p = new DefaultUnresolvedProperty(parentType, property.Name);
      p.SymbolKind = propertyType;
      TranslateModifiers(property.GetMethod ?? property.SetMethod, p);
      if (property.GetMethod != null && property.SetMethod != null)
        p.Accessibility = MergePropertyAccessibility (GetAccessibility (property.GetMethod.Attributes), GetAccessibility (property.SetMethod.Attributes));

      p.ReturnType = ReadTypeReference(property.PropertyType, typeAttributes: property);
      
      p.Getter = ReadMethod(property.GetMethod, parentType, SymbolKind.Accessor, p);
      p.Setter = ReadMethod(property.SetMethod, parentType, SymbolKind.Accessor, p);
      
      if (property.HasParameters) {
        foreach (ParameterDefinition par in property.Parameters) {
          p.Parameters.Add(ReadParameter(par));
        }
      }
      AddAttributes(property, p);

      var accessor = p.Getter ?? p.Setter;
      if (accessor != null && accessor.IsExplicitInterfaceImplementation) {
        p.Name = property.Name.Substring(property.Name.LastIndexOf('.') + 1);
        p.IsExplicitInterfaceImplementation = true;
        foreach (var mr in accessor.ExplicitInterfaceImplementations) {
          p.ExplicitInterfaceImplementations.Add(new AccessorOwnerMemberReference(mr));
        }
      }

      FinishReadMember(p, property);
      return p;
    }
    #endregion
    
    #region Read Event
    [CLSCompliant(false)]
    public IUnresolvedEvent ReadEvent(EventDefinition ev, IUnresolvedTypeDefinition parentType)
    {
      if (ev == null)
        throw new ArgumentNullException("ev");
      if (parentType == null)
        throw new ArgumentNullException("parentType");
      
      DefaultUnresolvedEvent e = new DefaultUnresolvedEvent(parentType, ev.Name);
      TranslateModifiers(ev.AddMethod, e);
      e.ReturnType = ReadTypeReference(ev.EventType, typeAttributes: ev);
      
      e.AddAccessor    = ReadMethod(ev.AddMethod,    parentType, SymbolKind.Accessor, e);
      e.RemoveAccessor = ReadMethod(ev.RemoveMethod, parentType, SymbolKind.Accessor, e);
      e.InvokeAccessor = ReadMethod(ev.InvokeMethod, parentType, SymbolKind.Accessor, e);
      
      AddAttributes(ev, e);
      
      var accessor = e.AddAccessor ?? e.RemoveAccessor ?? e.InvokeAccessor;
      if (accessor != null && accessor.IsExplicitInterfaceImplementation) {
        e.Name = ev.Name.Substring(ev.Name.LastIndexOf('.') + 1);
        e.IsExplicitInterfaceImplementation = true;
        foreach (var mr in accessor.ExplicitInterfaceImplementations) {
          e.ExplicitInterfaceImplementations.Add(new AccessorOwnerMemberReference(mr));
        }
      }

      FinishReadMember(e, ev);
      
      return e;
    }
    #endregion
    
    #region FinishReadMember / Interning
    void FinishReadMember(AbstractUnresolvedMember member, MemberReference cecilDefinition)
    {
      member.ApplyInterningProvider(interningProvider);
      member.Freeze();
      RegisterCecilObject(member, cecilDefinition);
    }
    #endregion
    
    #region Type system translation table
    readonly Dictionary<object, object> typeSystemTranslationTable;
    
    void RegisterCecilObject(IUnresolvedEntity typeSystemObject, MemberReference cecilObject)
    {
      if (OnEntityLoaded != null)
        OnEntityLoaded(typeSystemObject, cecilObject);
      
      AddToTypeSystemTranslationTable(typeSystemObject, cecilObject);
    }
    
    void AddToTypeSystemTranslationTable(object typeSystemObject, object cecilObject)
    {
      if (typeSystemTranslationTable != null) {
        // When lazy-loading, the dictionary might be shared between multiple cecil-loaders that are used concurrently
        lock (typeSystemTranslationTable) {
          typeSystemTranslationTable[typeSystemObject] = cecilObject;
        }
      }
    }
    
    T InternalGetCecilObject<T> (object typeSystemObject) where T : class
    {
      if (typeSystemObject == null)
        throw new ArgumentNullException ("typeSystemObject");
      if (!HasCecilReferences)
        throw new NotSupportedException ("This instance contains no cecil references.");
      object result;
      lock (typeSystemTranslationTable) {
        if (!typeSystemTranslationTable.TryGetValue (typeSystemObject, out result))
          return null;
      }
      return result as T;
    }
    
    [CLSCompliant(false)]
    public AssemblyDefinition GetCecilObject (IUnresolvedAssembly content)
    {
      return InternalGetCecilObject<AssemblyDefinition> (content);
    }
    
    [CLSCompliant(false)]
    public TypeDefinition GetCecilObject (IUnresolvedTypeDefinition type)
    {
      if (type == null)
        throw new ArgumentNullException ("type");
      return InternalGetCecilObject<TypeDefinition> (type);
    }
    
    [CLSCompliant(false)]
    public MethodDefinition GetCecilObject (IUnresolvedMethod method)
    {
      return InternalGetCecilObject<MethodDefinition> (method);
    }
    
    [CLSCompliant(false)]
    public FieldDefinition GetCecilObject (IUnresolvedField field)
    {
      return InternalGetCecilObject<FieldDefinition> (field);
    }
    
    [CLSCompliant(false)]
    public EventDefinition GetCecilObject (IUnresolvedEvent evt)
    {
      return InternalGetCecilObject<EventDefinition> (evt);
    }
    
    [CLSCompliant(false)]
    public PropertyDefinition GetCecilObject (IUnresolvedProperty property)
    {
      return InternalGetCecilObject<PropertyDefinition> (property);
    }
    #endregion
  }
}