2010-05-27 Jb Evain <jbevain@novell.com>

[mcs.git] / mcs / attribute.cs

//
// attribute.cs: Attribute Handler
//
// Author: Ravi Pratap (ravi@ximian.com)
//         Marek Safar (marek.safar@seznam.cz)
//
// Dual licensed under the terms of the MIT X11 or GNU GPL
//
// Copyright 2001-2003 Ximian, Inc (http://www.ximian.com)
// Copyright 2003-2008 Novell, Inc.
//

using System;
using System.Diagnostics;
using System.Collections.Generic;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;
using System.Security; 
using System.Security.Permissions;
using System.Text;
using System.IO;

namespace Mono.CSharp {

        /// <summary>
        ///   Base class for objects that can have Attributes applied to them.
        /// </summary>
        public abstract class Attributable {
                //
                // Holds all attributes attached to this element
                //
                protected Attributes attributes;

                public void AddAttributes (Attributes attrs, IMemberContext context)
                {
                        if (attrs == null)
                                return;

                        if (attributes == null)
                                attributes = attrs;
                        else
                                throw new NotImplementedException ();

                        attributes.AttachTo (this, context);
                }

                public Attributes OptAttributes {
                        get {
                                return attributes;
                        }
                        set {
                                attributes = value;
                        }
                }

                /// <summary>
                /// Use member-specific procedure to apply attribute @a in @cb to the entity being built in @builder
                /// </summary>
                public abstract void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa);

                /// <summary>
                /// Returns one AttributeTarget for this element.
                /// </summary>
                public abstract AttributeTargets AttributeTargets { get; }

                public abstract bool IsClsComplianceRequired ();

                /// <summary>
                /// Gets list of valid attribute targets for explicit target declaration.
                /// The first array item is default target. Don't break this rule.
                /// </summary>
                public abstract string[] ValidAttributeTargets { get; }
        };

        public class Attribute : Expression
        {
                public readonly string ExplicitTarget;
                public AttributeTargets Target;
                readonly ATypeNameExpression expression;

                Arguments PosArguments;
                Arguments NamedArguments;

                bool resolve_error;
                bool arg_resolved;
                readonly bool nameEscaped;

                //
                // An attribute can be attached to multiple targets (e.g. multiple fields)
                //
                protected Attributable[] targets;

                //
                // A member context for the attribute, it's much easier to hold it here
                // than trying to pull it during resolve
                //
                IMemberContext context;

                public static readonly AttributeUsageAttribute DefaultUsageAttribute = new AttributeUsageAttribute (AttributeTargets.All);
                static Assembly orig_sec_assembly;
                public static readonly object[] EmptyObject = new object [0];

                IList<KeyValuePair<MemberExpr, NamedArgument>> named_values;

                // Cache for parameter-less attributes
                static Dictionary<TypeSpec, MethodSpec> att_cache;

                public Attribute (string target, ATypeNameExpression expr, Arguments[] args, Location loc, bool nameEscaped)
                {
                        this.expression = expr;
                        if (args != null) {
                                PosArguments = args [0];
                                NamedArguments = args [1];                              
                        }
                        this.loc = loc;
                        ExplicitTarget = target;
                        this.nameEscaped = nameEscaped;
                }

                public Attribute Clone ()
                {
                        Attribute a = new Attribute (ExplicitTarget, expression, null, loc, nameEscaped);
                        a.PosArguments = PosArguments;
                        a.NamedArguments = NamedArguments;
                        return a;
                }

                static Attribute ()
                {
                        Reset ();
                }

                public static void Reset ()
                {
                        att_cache = new Dictionary<TypeSpec, MethodSpec> ();
                }

                //
                // When the same attribute is attached to multiple fiels
                // we use @target field as a list of targets. The attribute
                // has to be resolved only once but emitted for each target.
                //
                public virtual void AttachTo (Attributable target, IMemberContext context)
                {
                        if (this.targets == null) {
                                this.targets = new Attributable[] { target };
                                this.context = context;
                                return;
                        }

                        // Resize target array
                        Attributable[] new_array = new Attributable [this.targets.Length + 1];
                        targets.CopyTo (new_array, 0);
                        new_array [targets.Length] = target;
                        this.targets = new_array;

                        // No need to update context, different targets cannot have
                        // different contexts, it's enough to remove same attributes
                        // from secondary members.

                        target.OptAttributes = null;
                }

                static void Error_InvalidNamedArgument (ResolveContext rc, NamedArgument name)
                {
                        rc.Report.Error (617, name.Location, "`{0}' is not a valid named attribute argument. Named attribute arguments " +
                                      "must be fields which are not readonly, static, const or read-write properties which are " +
                                      "public and not static",
                              name.Name);
                }

                static void Error_InvalidNamedArgumentType (ResolveContext rc, NamedArgument name)
                {
                        rc.Report.Error (655, name.Location,
                                "`{0}' is not a valid named attribute argument because it is not a valid attribute parameter type",
                                name.Name);
                }

                public static void Error_AttributeArgumentNotValid (IMemberContext rc, Location loc)
                {
                        rc.Compiler.Report.Error (182, loc,
                                      "An attribute argument must be a constant expression, typeof " +
                                      "expression or array creation expression");
                }
                
                public void Error_MissingGuidAttribute ()
                {
                        Report.Error (596, Location, "The Guid attribute must be specified with the ComImport attribute");
                }

                public void Error_MisusedExtensionAttribute ()
                {
                        Report.Error (1112, Location, "Do not use `{0}' directly. Use parameter modifier `this' instead", GetSignatureForError ());
                }

                public void Error_MisusedDynamicAttribute ()
                {
                        Report.Error (1970, loc, "Do not use `{0}' directly. Use `dynamic' keyword instead", GetSignatureForError ());
                }

                /// <summary>
                /// This is rather hack. We report many emit attribute error with same error to be compatible with
                /// csc. But because csc has to report them this way because error came from ilasm we needn't.
                /// </summary>
                public void Error_AttributeEmitError (string inner)
                {
                        Report.Error (647, Location, "Error during emitting `{0}' attribute. The reason is `{1}'",
                                      TypeManager.CSharpName (Type), inner);
                }

                public void Error_InvalidSecurityParent ()
                {
                        Error_AttributeEmitError ("it is attached to invalid parent");
                }

                Attributable Owner {
                        get {
                                return targets [0];
                        }
                }

                protected virtual TypeExpr ResolveAsTypeTerminal (Expression expr, IMemberContext ec)
                {
                        return expr.ResolveAsTypeTerminal (ec, false);
                }

                TypeSpec ResolvePossibleAttributeType (ATypeNameExpression expr, ref bool is_attr)
                {
                        TypeExpr te = ResolveAsTypeTerminal (expr, context);
                        if (te == null)
                                return null;

                        TypeSpec t = te.Type;
                        if (t.IsAttribute) {
                                is_attr = true;
                        } else {
                                Report.SymbolRelatedToPreviousError (t);
                                Report.Error (616, Location, "`{0}': is not an attribute class", TypeManager.CSharpName (t));
                        }
                        return t;
                }

                /// <summary>
                ///   Tries to resolve the type of the attribute. Flags an error if it can't, and complain is true.
                /// </summary>
                void ResolveAttributeType ()
                {
                        SessionReportPrinter resolve_printer = new SessionReportPrinter ();
                        ReportPrinter prev_recorder = context.Compiler.Report.SetPrinter (resolve_printer);

                        bool t1_is_attr = false;
                        bool t2_is_attr = false;
                        TypeSpec t1, t2;
                        ATypeNameExpression expanded = null;

                        try {
                                t1 = ResolvePossibleAttributeType (expression, ref t1_is_attr);

                                if (nameEscaped) {
                                        t2 = null;
                                } else {
                                        expanded = (ATypeNameExpression) expression.Clone (null);
                                        expanded.Name += "Attribute";

                                        t2 = ResolvePossibleAttributeType (expanded, ref t2_is_attr);
                                }

                                resolve_printer.EndSession ();
                        } finally {
                                context.Compiler.Report.SetPrinter (prev_recorder);
                        }

                        if (t1_is_attr && t2_is_attr) {
                                Report.Error (1614, Location, "`{0}' is ambiguous between `{1}' and `{2}'. Use either `@{0}' or `{0}Attribute'",
                                        GetSignatureForError (), expression.GetSignatureForError (), expanded.GetSignatureForError ());
                                resolve_error = true;
                                return;
                        }

                        if (t1_is_attr) {
                                Type = t1;
                                return;
                        }

                        if (t2_is_attr) {
                                Type = t2;
                                return;
                        }

                        resolve_printer.Merge (prev_recorder);
                        resolve_error = true;
                }

                public virtual TypeSpec ResolveType ()
                {
                        if (Type == null && !resolve_error)
                                ResolveAttributeType ();
                        return Type;
                }

                public override string GetSignatureForError ()
                {
                        if (Type != null)
                                return TypeManager.CSharpName (Type);

                        return expression.GetSignatureForError ();
                }

                public bool HasSecurityAttribute {
                        get {
                                PredefinedAttribute pa = PredefinedAttributes.Get.Security;
                                return pa.IsDefined && TypeManager.IsSubclassOf (type, pa.Type);
                        }
                }

                public bool IsValidSecurityAttribute ()
                {
                        return HasSecurityAttribute && IsSecurityActionValid (false);
                }

                static bool IsValidArgumentType (TypeSpec t)
                {
                        if (t.IsArray)
                                t = TypeManager.GetElementType (t);

                        return t == TypeManager.string_type ||
                                TypeManager.IsPrimitiveType (t) ||
                                TypeManager.IsEnumType (t) ||
                                t == TypeManager.object_type ||
                                t == TypeManager.type_type;
                }

                // TODO: Don't use this ambiguous value
                public string Name {
                        get { return expression.Name; }
                }

                void ApplyModuleCharSet (ResolveContext rc)
                {
                        if (Type != PredefinedAttributes.Get.DllImport)
                                return;

                        if (!RootContext.ToplevelTypes.HasDefaultCharSet)
                                return;

                        const string CharSetEnumMember = "CharSet";
                        if (NamedArguments == null) {
                                NamedArguments = new Arguments (1);
                        } else {
                                foreach (NamedArgument a in NamedArguments) {
                                        if (a.Name == CharSetEnumMember)
                                                return;
                                }
                        }

                        var char_set = Import.ImportType (typeof (CharSet));
                        NamedArguments.Add (new NamedArgument (CharSetEnumMember, loc,
                                Constant.CreateConstant (rc, char_set, RootContext.ToplevelTypes.DefaultCharSet, Location)));
                }

                public Report Report {
                        get { return context.Compiler.Report; }
                }

                public MethodSpec Resolve ()
                {
                        if (resolve_error)
                                return null;

                        resolve_error = true;
                        arg_resolved = true;

                        if (Type == null) {
                                ResolveAttributeType ();
                                if (Type == null)
                                        return null;
                        }

                        if (Type.IsAbstract) {
                                Report.Error (653, Location, "Cannot apply attribute class `{0}' because it is abstract", GetSignatureForError ());
                                return null;
                        }

                        ObsoleteAttribute obsolete_attr = Type.GetAttributeObsolete ();
                        if (obsolete_attr != null) {
                                AttributeTester.Report_ObsoleteMessage (obsolete_attr, TypeManager.CSharpName (Type), Location, Report);
                        }

                        MethodSpec ctor;
                        // Try if the attribute is simple has been resolved before
                        if (PosArguments == null && NamedArguments == null) {
                                if (att_cache.TryGetValue (Type, out ctor)) {
                                        resolve_error = false;
                                        return ctor;
                                }
                        }

                        ResolveContext rc = new ResolveContext (context, ResolveContext.Options.ConstantScope);
                        ctor = ResolveConstructor (rc);
                        if (ctor == null) {
                                return null;
                        }

                        ApplyModuleCharSet (rc);

                        if (NamedArguments != null && !ResolveNamedArguments (rc)) {
                                return null;
                        }

                        resolve_error = false;
                        return ctor;
                }

                protected virtual MethodSpec ResolveConstructor (ResolveContext ec)
                {
                        if (PosArguments != null) {
                                bool dynamic;
                                PosArguments.Resolve (ec, out dynamic);
                                if (dynamic) {
                                        Error_AttributeArgumentNotValid (ec, loc);
                                        return null;
                                }
                        }

                        MethodGroupExpr mg = MemberLookupFinal (ec, ec.CurrentType,
                                Type, ConstructorInfo.ConstructorName, 0, MemberKind.Constructor,
                                BindingRestriction.AccessibleOnly | BindingRestriction.DeclaredOnly,
                                Location) as MethodGroupExpr;

                        if (mg == null)
                                throw new NotImplementedException ();

                        mg = mg.OverloadResolve (ec, ref PosArguments, false, Location);
                        if (mg == null)
                                return null;
                        
                        var constructor = (MethodSpec) mg;
                        return constructor;
                }

                protected virtual bool ResolveNamedArguments (ResolveContext ec)
                {
                        int named_arg_count = NamedArguments.Count;
                        var seen_names = new List<string> (named_arg_count);

                        named_values = new List<KeyValuePair<MemberExpr, NamedArgument>> (named_arg_count);
                        
                        foreach (NamedArgument a in NamedArguments) {
                                string name = a.Name;
                                if (seen_names.Contains (name)) {
                                        ec.Report.Error (643, a.Location, "Duplicate named attribute `{0}' argument", name);
                                        continue;
                                }                       
        
                                seen_names.Add (name);

                                a.Resolve (ec);

                                Expression member = Expression.MemberLookup (ec.Compiler,
                                        ec.CurrentType, Type, name, 0,
                                        MemberKind.All,
                                        BindingRestriction.AccessibleOnly,
                                        Location);

                                if (member == null) {
                                        member = Expression.MemberLookup (ec.Compiler, ec.CurrentType, Type, name, 0,
                                                MemberKind.All, BindingRestriction.None,
                                                Location);

                                        if (member != null) {
                                                ec.Report.SymbolRelatedToPreviousError (member.Type);
                                                Expression.ErrorIsInaccesible (Location, member.GetSignatureForError (), ec.Report);
                                                return false;
                                        }
                                }

                                if (member == null){
                                        Expression.Error_TypeDoesNotContainDefinition (ec, Location, Type, name);
                                        return false;
                                }
                                
                                if (!(member is PropertyExpr || member is FieldExpr)) {
                                        Error_InvalidNamedArgument (ec, a);
                                        return false;
                                }

                                ObsoleteAttribute obsolete_attr;

                                if (member is PropertyExpr) {
                                        var pi = ((PropertyExpr) member).PropertyInfo;

                                        if (!pi.HasSet || !pi.HasGet || pi.IsStatic) {
                                                ec.Report.SymbolRelatedToPreviousError (pi);
                                                Error_InvalidNamedArgument (ec, a);
                                                return false;
                                        }

                                        if (!IsValidArgumentType (member.Type)) {
                                                ec.Report.SymbolRelatedToPreviousError (pi);
                                                Error_InvalidNamedArgumentType (ec, a);
                                                return false;
                                        }

                                        obsolete_attr = pi.GetAttributeObsolete ();
                                } else {
                                        var fi = ((FieldExpr) member).Spec;

                                        if (fi.IsReadOnly || fi.IsStatic) {
                                                Error_InvalidNamedArgument (ec, a);
                                                return false;
                                        }

                                        if (!IsValidArgumentType (member.Type)) {
                                                ec.Report.SymbolRelatedToPreviousError (fi);
                                                Error_InvalidNamedArgumentType (ec, a);
                                                return false;
                                        }

                                        obsolete_attr = fi.GetAttributeObsolete ();
                                }

                                if (obsolete_attr != null && !context.IsObsolete)
                                        AttributeTester.Report_ObsoleteMessage (obsolete_attr, member.GetSignatureForError (), member.Location, Report);

                                if (a.Type != member.Type) {
                                        a.Expr = Convert.ImplicitConversionRequired (ec, a.Expr, member.Type, a.Expr.Location);
                                }

                                if (a.Expr != null)
                                        named_values.Add (new KeyValuePair<MemberExpr, NamedArgument> ((MemberExpr) member, a));
                        }

                        return true;
                }

                /// <summary>
                ///   Get a string containing a list of valid targets for the attribute 'attr'
                /// </summary>
                public string GetValidTargets ()
                {
                        StringBuilder sb = new StringBuilder ();
                        AttributeTargets targets = Type.GetAttributeUsage (PredefinedAttributes.Get.AttributeUsage).ValidOn;

                        if ((targets & AttributeTargets.Assembly) != 0)
                                sb.Append ("assembly, ");

                        if ((targets & AttributeTargets.Module) != 0)
                                sb.Append ("module, ");

                        if ((targets & AttributeTargets.Class) != 0)
                                sb.Append ("class, ");

                        if ((targets & AttributeTargets.Struct) != 0)
                                sb.Append ("struct, ");

                        if ((targets & AttributeTargets.Enum) != 0)
                                sb.Append ("enum, ");

                        if ((targets & AttributeTargets.Constructor) != 0)
                                sb.Append ("constructor, ");

                        if ((targets & AttributeTargets.Method) != 0)
                                sb.Append ("method, ");

                        if ((targets & AttributeTargets.Property) != 0)
                                sb.Append ("property, indexer, ");

                        if ((targets & AttributeTargets.Field) != 0)
                                sb.Append ("field, ");

                        if ((targets & AttributeTargets.Event) != 0)
                                sb.Append ("event, ");

                        if ((targets & AttributeTargets.Interface) != 0)
                                sb.Append ("interface, ");

                        if ((targets & AttributeTargets.Parameter) != 0)
                                sb.Append ("parameter, ");

                        if ((targets & AttributeTargets.Delegate) != 0)
                                sb.Append ("delegate, ");

                        if ((targets & AttributeTargets.ReturnValue) != 0)
                                sb.Append ("return, ");

                        if ((targets & AttributeTargets.GenericParameter) != 0)
                                sb.Append ("type parameter, ");

                        return sb.Remove (sb.Length - 2, 2).ToString ();
                }

                public AttributeUsageAttribute GetAttributeUsageAttribute ()
                {
                        if (!arg_resolved)
                                // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
                                // But because a lot of attribute class code must be rewritten will be better to wait...
                                Resolve ();

                        if (resolve_error)
                                return DefaultUsageAttribute;

                        AttributeUsageAttribute usage_attribute = new AttributeUsageAttribute ((AttributeTargets)((Constant) PosArguments [0].Expr).GetValue ());

                        var field = GetPropertyValue ("AllowMultiple") as BoolConstant;
                        if (field != null)
                                usage_attribute.AllowMultiple = field.Value;

                        field = GetPropertyValue ("Inherited") as BoolConstant;
                        if (field != null)
                                usage_attribute.Inherited = field.Value;

                        return usage_attribute;
                }

                /// <summary>
                /// Returns custom name of indexer
                /// </summary>
                public string GetIndexerAttributeValue ()
                {
                        if (!arg_resolved)
                                // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
                                // But because a lot of attribute class code must be rewritten will be better to wait...
                                Resolve ();

                        if (resolve_error)
                                return null;

                        return ((Constant) PosArguments [0].Expr).GetValue () as string;
                }

                /// <summary>
                /// Returns condition of ConditionalAttribute
                /// </summary>
                public string GetConditionalAttributeValue ()
                {
                        if (!arg_resolved)
                                // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
                                // But because a lot of attribute class code must be rewritten will be better to wait...
                                Resolve ();

                        if (resolve_error)
                                return null;

                        return ((Constant) PosArguments[0].Expr).GetValue () as string;
                }

                /// <summary>
                /// Creates the instance of ObsoleteAttribute from this attribute instance
                /// </summary>
                public ObsoleteAttribute GetObsoleteAttribute ()
                {
                        if (!arg_resolved) {
                                // corlib only case when obsolete is used before is resolved
                                var c = type.MemberDefinition as Class;
                                if (c != null && !c.HasMembersDefined)
                                        c.Define ();
                                
                                // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
                                // But because a lot of attribute class code must be rewritten will be better to wait...
                                Resolve ();
                        }

                        if (resolve_error)
                                return null;

                        if (PosArguments == null)
                                return new ObsoleteAttribute ();

                        string msg = ((Constant) PosArguments[0].Expr).GetValue () as string;
                        if (PosArguments.Count == 1)
                                return new ObsoleteAttribute (msg);

                        return new ObsoleteAttribute (msg, ((BoolConstant) PosArguments[1].Expr).Value);
                }

                /// <summary>
                /// Returns value of CLSCompliantAttribute contructor parameter but because the method can be called
                /// before ApplyAttribute. We need to resolve the arguments.
                /// This situation occurs when class deps is differs from Emit order.  
                /// </summary>
                public bool GetClsCompliantAttributeValue ()
                {
                        if (!arg_resolved)
                                // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
                                // But because a lot of attribute class code must be rewritten will be better to wait...
                                Resolve ();

                        if (resolve_error)
                                return false;

                        return ((BoolConstant) PosArguments[0].Expr).Value;
                }

                public TypeSpec GetCoClassAttributeValue ()
                {
                        if (!arg_resolved)
                                Resolve ();

                        if (resolve_error)
                                return null;

                        return GetArgumentType ();
                }

                public bool CheckTarget ()
                {
                        string[] valid_targets = Owner.ValidAttributeTargets;
                        if (ExplicitTarget == null || ExplicitTarget == valid_targets [0]) {
                                Target = Owner.AttributeTargets;
                                return true;
                        }

                        // TODO: we can skip the first item
                        if (Array.Exists (valid_targets, i => i == ExplicitTarget)) {
                                switch (ExplicitTarget) {
                                case "return": Target = AttributeTargets.ReturnValue; return true;
                                case "param": Target = AttributeTargets.Parameter; return true;
                                case "field": Target = AttributeTargets.Field; return true;
                                case "method": Target = AttributeTargets.Method; return true;
                                case "property": Target = AttributeTargets.Property; return true;
                                }
                                throw new InternalErrorException ("Unknown explicit target: " + ExplicitTarget);
                        }
                                
                        StringBuilder sb = new StringBuilder ();
                        foreach (string s in valid_targets) {
                                sb.Append (s);
                                sb.Append (", ");
                        }
                        sb.Remove (sb.Length - 2, 2);
                        Report.Error (657, Location, "`{0}' is not a valid attribute location for this declaration. " +
                                "Valid attribute locations for this declaration are `{1}'", ExplicitTarget, sb.ToString ());
                        return false;
                }

                /// <summary>
                /// Tests permitted SecurityAction for assembly or other types
                /// </summary>
                protected virtual bool IsSecurityActionValid (bool for_assembly)
                {
                        SecurityAction action = GetSecurityActionValue ();

                        switch (action) {
                        case SecurityAction.Demand:
                        case SecurityAction.Assert:
                        case SecurityAction.Deny:
                        case SecurityAction.PermitOnly:
                        case SecurityAction.LinkDemand:
                        case SecurityAction.InheritanceDemand:
                                if (!for_assembly)
                                        return true;
                                break;

                        case SecurityAction.RequestMinimum:
                        case SecurityAction.RequestOptional:
                        case SecurityAction.RequestRefuse:
                                if (for_assembly)
                                        return true;
                                break;

                        default:
                                Error_AttributeEmitError ("SecurityAction is out of range");
                                return false;
                        }

                        Error_AttributeEmitError (String.Concat ("SecurityAction `", action, "' is not valid for this declaration"));
                        return false;
                }

                System.Security.Permissions.SecurityAction GetSecurityActionValue ()
                {
                        return (SecurityAction) ((Constant) PosArguments[0].Expr).GetTypedValue ();
                }

                /// <summary>
                /// Creates instance of SecurityAttribute class and add result of CreatePermission method to permission table.
                /// </summary>
                /// <returns></returns>
                public void ExtractSecurityPermissionSet (Dictionary<SecurityAction, PermissionSet> permissions)
                {
                        Type orig_assembly_type = null;

                        if (Type.MemberDefinition is TypeContainer) {
                                if (!RootContext.StdLib) {
                                        orig_assembly_type = System.Type.GetType (Type.GetMetaInfo ().FullName);
                                } else {
                                        string orig_version_path = Environment.GetEnvironmentVariable ("__SECURITY_BOOTSTRAP_DB");
                                        if (orig_version_path == null) {
                                                Error_AttributeEmitError ("security custom attributes can not be referenced from defining assembly");
                                                return;
                                        }

                                        if (orig_sec_assembly == null) {
                                                string file = Path.Combine (orig_version_path, Driver.OutputFile);
                                                orig_sec_assembly = Assembly.LoadFile (file);
                                        }

                                        orig_assembly_type = orig_sec_assembly.GetType (Type.GetMetaInfo ().FullName, true);
                                        if (orig_assembly_type == null) {
                                                Report.Warning (-112, 1, Location, "Self-referenced security attribute `{0}' " +
                                                                "was not found in previous version of assembly");
                                                return;
                                        }
                                }
                        }

                        SecurityAttribute sa;
                        object[] args;

                        // For all non-selfreferencing security attributes we can avoid all hacks
                        if (orig_assembly_type == null) {
                                args = new object[PosArguments.Count];
                                for (int j = 0; j < args.Length; ++j) {
                                        args[j] = ((Constant) PosArguments[j].Expr).GetTypedValue ();
                                }

                                sa = (SecurityAttribute) Activator.CreateInstance (Type.GetMetaInfo (), args);

                                if (named_values != null) {
                                        for (int i = 0; i < named_values.Count; ++i) {
                                                PropertyInfo pi = ((PropertyExpr) named_values[i].Key).PropertyInfo.MetaInfo;
                                                pi.SetValue (sa, ((Constant) named_values [i].Value.Expr).GetTypedValue (), null);
                                        }
                                }
                        } else {
                                // HACK: All security attributes have same ctor syntax
                                args = new object[] { GetSecurityActionValue () };
                                sa = (SecurityAttribute) Activator.CreateInstance (orig_assembly_type, args);

                                // All types are from newly created assembly but for invocation with old one we need to convert them
                                if (named_values != null) {
                                        for (int i = 0; i < named_values.Count; ++i) {
                                                PropertyInfo emited_pi = ((PropertyExpr) named_values[i].Key).PropertyInfo.MetaInfo;
                                                // FIXME: We are missing return type filter
                                                // TODO: pi can be null
                                                PropertyInfo pi = orig_assembly_type.GetProperty (emited_pi.Name);

                                                pi.SetValue (sa, ((Constant) named_values[i].Value.Expr).GetTypedValue (), null);
                                        }
                                }
                        }

                        IPermission perm;
                        perm = sa.CreatePermission ();
                        SecurityAction action = (SecurityAction) args [0];

                        // IS is correct because for corlib we are using an instance from old corlib
                        if (!(perm is System.Security.CodeAccessPermission)) {
                                switch (action) {
                                case SecurityAction.Demand:
                                        action = (SecurityAction)13;
                                        break;
                                case SecurityAction.LinkDemand:
                                        action = (SecurityAction)14;
                                        break;
                                case SecurityAction.InheritanceDemand:
                                        action = (SecurityAction)15;
                                        break;
                                }
                        }

                        PermissionSet ps;
                        if (!permissions.TryGetValue (action, out ps)) {
                                if (sa is PermissionSetAttribute)
                                        ps = new PermissionSet (sa.Unrestricted ? PermissionState.Unrestricted : PermissionState.None);
                                else
                                        ps = new PermissionSet (PermissionState.None);

                                permissions.Add (action, ps);
                        } else if (!ps.IsUnrestricted () && (sa is PermissionSetAttribute) && sa.Unrestricted) {
                                ps = ps.Union (new PermissionSet (PermissionState.Unrestricted));
                                permissions [action] = ps;
                        }
                        ps.AddPermission (perm);
                }

                public Constant GetPropertyValue (string name)
                {
                        if (named_values == null)
                                return null;

                        for (int i = 0; i < named_values.Count; ++i) {
                                if (named_values [i].Value.Name == name)
                                        return named_values [i].Value.Expr as Constant;
                        }

                        return null;
                }

                //
                // Theoretically, we can get rid of this, since FieldBuilder.SetCustomAttribute()
                // and ParameterBuilder.SetCustomAttribute() are supposed to handle this attribute.
                // However, we can't, since it appears that the .NET 1.1 SRE hangs when given a MarshalAsAttribute.
                //
#if false
                public UnmanagedMarshal GetMarshal (Attributable attr)
                {
                        UnmanagedType UnmanagedType;
                        if (!RootContext.StdLib || pos_values [0].GetType () != typeof (UnmanagedType))
                                UnmanagedType = (UnmanagedType) System.Enum.ToObject (typeof (UnmanagedType), pos_values [0]);
                        else
                                UnmanagedType = (UnmanagedType) pos_values [0];

                        object value = GetFieldValue ("SizeParamIndex");
                        if (value != null && UnmanagedType != UnmanagedType.LPArray) {
                                Error_AttributeEmitError ("SizeParamIndex field is not valid for the specified unmanaged type");
                                return null;
                        }

                        object o = GetFieldValue ("ArraySubType");
                        UnmanagedType array_sub_type = o == null ? (UnmanagedType) 0x50 /* NATIVE_MAX */ : (UnmanagedType) o;

                        switch (UnmanagedType) {
                        case UnmanagedType.CustomMarshaler: {
                                MethodInfo define_custom = typeof (UnmanagedMarshal).GetMethod ("DefineCustom",
                                        BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
                                if (define_custom == null) {
                                        Report.RuntimeMissingSupport (Location, "set marshal info");
                                        return null;
                                }
                                
                                object [] args = new object [4];
                                args [0] = GetFieldValue ("MarshalTypeRef");
                                args [1] = GetFieldValue ("MarshalCookie");
                                args [2] = GetFieldValue ("MarshalType");
                                args [3] = Guid.Empty;
                                return (UnmanagedMarshal) define_custom.Invoke (null, args);
                        }
                        case UnmanagedType.LPArray: {
                                object size_const = GetFieldValue ("SizeConst");
                                object size_param_index = GetFieldValue ("SizeParamIndex");

                                if ((size_const != null) || (size_param_index != null)) {
                                        MethodInfo define_array = typeof (UnmanagedMarshal).GetMethod ("DefineLPArrayInternal",
                                                BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
                                        if (define_array == null) {
                                                Report.RuntimeMissingSupport (Location, "set marshal info");
                                                return null;
                                        }
                                
                                        object [] args = new object [3];
                                        args [0] = array_sub_type;
                                        args [1] = size_const == null ? -1 : size_const;
                                        args [2] = size_param_index == null ? -1 : size_param_index;
                                        return (UnmanagedMarshal) define_array.Invoke (null, args);
                                }
                                else
                                        return UnmanagedMarshal.DefineLPArray (array_sub_type);
                        }
                        case UnmanagedType.SafeArray:
                                return UnmanagedMarshal.DefineSafeArray (array_sub_type);

                        case UnmanagedType.ByValArray:
                                FieldBase fm = attr as FieldBase;
                                if (fm == null) {
                                        Error_AttributeEmitError ("Specified unmanaged type is only valid on fields");
                                        return null;
                                }
                                return UnmanagedMarshal.DefineByValArray ((int) GetFieldValue ("SizeConst"));

                        case UnmanagedType.ByValTStr:
                                return UnmanagedMarshal.DefineByValTStr ((int) GetFieldValue ("SizeConst"));

                        default:
                                return UnmanagedMarshal.DefineUnmanagedMarshal (UnmanagedType);
                        }
                }

                object GetFieldValue (string name)
                {
                        int i;
                        if (field_info_arr == null)
                                return null;
                        i = 0;
                        foreach (FieldInfo fi in field_info_arr) {
                                if (fi.Name == name)
                                        return GetValue (field_values_arr [i]);
                                i++;
                        }
                        return null;
                }

                static object GetValue (object value)
                {
                        if (value is EnumConstant)
                                return ((EnumConstant) value).GetValue ();
                        else
                                return value;                           
                }
                
#endif

                public CharSet GetCharSetValue ()
                {
                        return (CharSet)System.Enum.Parse (typeof (CharSet), ((Constant) PosArguments [0].Expr).GetValue ().ToString ());
                }

                public bool HasField (string fieldName)
                {
                        if (named_values == null)
                                return false;

                        foreach (var na in named_values) {
                                if (na.Value.Name == fieldName)
                                        return true;
                        }

                        return false;
                }

                public bool IsInternalMethodImplAttribute {
                        get {
                                if (Type != PredefinedAttributes.Get.MethodImpl)
                                        return false;

                                MethodImplOptions options;
                                if (PosArguments[0].Type.GetMetaInfo () != typeof (MethodImplOptions))
                                        options = (MethodImplOptions) System.Enum.ToObject (typeof (MethodImplOptions), ((Constant) PosArguments[0].Expr).GetValue ());
                                else
                                        options = (MethodImplOptions) ((Constant) PosArguments [0].Expr).GetValue ();

                                return (options & MethodImplOptions.InternalCall) != 0;
                        }
                }

                public LayoutKind GetLayoutKindValue ()
                {
                        if (!RootContext.StdLib || PosArguments[0].Type.GetMetaInfo () != typeof (LayoutKind))
                                return (LayoutKind) System.Enum.ToObject (typeof (LayoutKind), ((Constant) PosArguments[0].Expr).GetValue ());

                        return (LayoutKind) ((Constant) PosArguments[0].Expr).GetValue ();
                }

                public Constant GetParameterDefaultValue (out TypeSpec type)
                {
                        var expr = PosArguments[0].Expr;

                        if (expr is TypeCast)
                                expr = ((TypeCast) expr).Child;

                        type = expr.Type;
                        return expr as Constant;
                }

                public override bool Equals (object obj)
                {
                        Attribute a = obj as Attribute;
                        if (a == null)
                                return false;

                        return Type == a.Type && Target == a.Target;
                }

                public override int GetHashCode ()
                {
                        return type.GetHashCode () ^ Target.GetHashCode ();
                }

                /// <summary>
                /// Emit attribute for Attributable symbol
                /// </summary>
                public void Emit (Dictionary<Attribute, List<Attribute>> allEmitted)
                {
                        var ctor = Resolve ();
                        if (ctor == null)
                                return;

                        AttributeUsageAttribute usage_attr = Type.GetAttributeUsage (PredefinedAttributes.Get.AttributeUsage);
                        if ((usage_attr.ValidOn & Target) == 0) {
                                Report.Error (592, Location, "The attribute `{0}' is not valid on this declaration type. " +
                                              "It is valid on `{1}' declarations only",
                                        GetSignatureForError (), GetValidTargets ());
                                return;
                        }

                        var predefined = PredefinedAttributes.Get;

                        AttributeEncoder encoder = new AttributeEncoder (false);

                        if (PosArguments != null) {
                                var param_types = ctor.Parameters.Types;
                                for (int j = 0; j < PosArguments.Count; ++j) {
                                        var pt = param_types[j];
                                        if (!IsValidArgumentType (pt)) {
                                                Error_AttributeArgumentNotValid (context, loc);
                                                return;
                                        }

                                        var arg_expr = PosArguments[j].Expr;
                                        if (j == 0) {
                                                if (Type == predefined.IndexerName || Type == predefined.Conditional) {
                                                        string v = ((StringConstant) arg_expr).Value;
                                                        if (!Tokenizer.IsValidIdentifier (v) || Tokenizer.IsKeyword (v)) {
                                                                context.Compiler.Report.Error (633, arg_expr.Location,
                                                                        "The argument to the `{0}' attribute must be a valid identifier", GetSignatureForError ());
                                                        }
                                                } else if (Type == predefined.Guid) {
                                                        try {
                                                                string v = ((StringConstant) arg_expr).Value;
                                                                new Guid (v);
                                                        } catch (Exception e) {
                                                                Error_AttributeEmitError (e.Message);
                                                                return;
                                                        }
                                                } else if (Type == predefined.AttributeUsage) {
                                                        int v = ((IntConstant)((EnumConstant) arg_expr).Child).Value;
                                                        if (v == 0) {
                                                                context.Compiler.Report.Error (591, Location, "Invalid value for argument to `{0}' attribute",
                                                                        "System.AttributeUsage");
                                                        }
                                                } else if (Type == predefined.MethodImpl && pt == TypeManager.short_type &&
                                                        !System.Enum.IsDefined (typeof (MethodImplOptions), ((Constant) arg_expr).GetValue ().ToString ())) {
                                                        Error_AttributeEmitError ("Incorrect argument value.");
                                                        return;
                                                }
                                        }

                                        arg_expr.EncodeAttributeValue (context, encoder, pt);
                                }
                        }

                        if (named_values != null) {
                                encoder.Stream.Write ((ushort) named_values.Count);
                                foreach (var na in named_values) {
                                        if (na.Key is FieldExpr)
                                                encoder.Stream.Write ((byte) 0x53);
                                        else
                                                encoder.Stream.Write ((byte) 0x54);

                                        encoder.Encode (na.Key.Type);
                                        encoder.Encode (na.Value.Name);
                                        na.Value.Expr.EncodeAttributeValue (context, encoder, na.Key.Type);
                                }
                        } else {
                                encoder.Stream.Write ((ushort) 0);
                        }

                        byte[] cdata = encoder.ToArray ();

                        try {
                                foreach (Attributable target in targets)
                                        target.ApplyAttributeBuilder (this, ctor, cdata, predefined);
                        } catch (Exception e) {
                                Error_AttributeEmitError (e.Message);
                                return;
                        }

                        if (!usage_attr.AllowMultiple && allEmitted != null) {
                                if (allEmitted.ContainsKey (this)) {
                                        var a = allEmitted [this];
                                        if (a == null) {
                                                a = new List<Attribute> (2);
                                                allEmitted [this] = a;
                                        }
                                        a.Add (this);
                                } else {
                                        allEmitted.Add (this, null);
                                }
                        }

                        if (!RootContext.VerifyClsCompliance)
                                return;

                        // Here we are testing attribute arguments for array usage (error 3016)
                        if (Owner.IsClsComplianceRequired ()) {
                                if (PosArguments != null)
                                        PosArguments.CheckArrayAsAttribute (context.Compiler);
                        
                                if (NamedArguments == null)
                                        return;

                                NamedArguments.CheckArrayAsAttribute (context.Compiler);
                        }
                }

                private Expression GetValue () 
                {
                        if (PosArguments == null || PosArguments.Count < 1)
                                return null;

                        return PosArguments [0].Expr;
                }

                public string GetString () 
                {
                        Expression e = GetValue ();
                        if (e is StringConstant)
                                return ((StringConstant)e).Value;
                        return null;
                }

                public bool GetBoolean () 
                {
                        Expression e = GetValue ();
                        if (e is BoolConstant)
                                return ((BoolConstant)e).Value;
                        return false;
                }

                public TypeSpec GetArgumentType ()
                {
                        TypeOf e = GetValue () as TypeOf;
                        if (e == null)
                                return null;
                        return e.TypeArgument;
                }

                public override Expression CreateExpressionTree (ResolveContext ec)
                {
                        throw new NotSupportedException ("ET");
                }

                protected override Expression DoResolve (ResolveContext ec)
                {
                        throw new NotImplementedException ();
                }

                public override void Emit (EmitContext ec)
                {
                        throw new NotImplementedException ();
                }
        }
        

        /// <summary>
        /// For global attributes (assembly, module) we need special handling.
        /// Attributes can be located in the several files
        /// </summary>
        public class GlobalAttribute : Attribute
        {
                public readonly NamespaceEntry ns;

                public GlobalAttribute (NamespaceEntry ns, string target, ATypeNameExpression expression,
                                        Arguments[] args, Location loc, bool nameEscaped):
                        base (target, expression, args, loc, nameEscaped)
                {
                        this.ns = ns;
                }
                
                public override void AttachTo (Attributable target, IMemberContext context)
                {
                        if (ExplicitTarget == "assembly") {
                                base.AttachTo (CodeGen.Assembly, context);
                                return;
                        }

                        if (ExplicitTarget == "module") {
                                base.AttachTo (RootContext.ToplevelTypes, context);
                                return;
                        }

                        throw new NotImplementedException ("Unknown global explicit target " + ExplicitTarget);
                }

                void Enter ()
                {
                        // RootContext.ToplevelTypes has a single NamespaceEntry which gets overwritten
                        // each time a new file is parsed.  However, we need to use the NamespaceEntry
                        // in effect where the attribute was used.  Since code elsewhere cannot assume
                        // that the NamespaceEntry is right, just overwrite it.
                        //
                        // Precondition: RootContext.ToplevelTypes == null

                        if (RootContext.ToplevelTypes.NamespaceEntry != null)
                                throw new InternalErrorException (Location + " non-null NamespaceEntry");

                        RootContext.ToplevelTypes.NamespaceEntry = ns;
                }

                protected override bool IsSecurityActionValid (bool for_assembly)
                {
                        return base.IsSecurityActionValid (true);
                }

                void Leave ()
                {
                        RootContext.ToplevelTypes.NamespaceEntry = null;
                }

                protected override TypeExpr ResolveAsTypeTerminal (Expression expr, IMemberContext ec)
                {
                        try {
                                Enter ();
                                return base.ResolveAsTypeTerminal (expr, ec);
                        }
                        finally {
                                Leave ();
                        }
                }

                protected override MethodSpec ResolveConstructor (ResolveContext ec)
                {
                        try {
                                Enter ();
                                return base.ResolveConstructor (ec);
                        }
                        finally {
                                Leave ();
                        }
                }

                protected override bool ResolveNamedArguments (ResolveContext ec)
                {
                        try {
                                Enter ();
                                return base.ResolveNamedArguments (ec);
                        }
                        finally {
                                Leave ();
                        }
                }
        }

        public class Attributes {
                public readonly List<Attribute> Attrs;

                public Attributes (Attribute a)
                {
                        Attrs = new List<Attribute> ();
                        Attrs.Add (a);
                }

                public Attributes (List<Attribute> attrs)
                {
                        Attrs = attrs;
                }

                public void AddAttributes (List<Attribute> attrs)
                {
                        Attrs.AddRange (attrs);
                }

                public void AttachTo (Attributable attributable, IMemberContext context)
                {
                        foreach (Attribute a in Attrs)
                                a.AttachTo (attributable, context);
                }

                public Attributes Clone ()
                {
                        var al = new List<Attribute> (Attrs.Count);
                        foreach (Attribute a in Attrs)
                                al.Add (a.Clone ());

                        return new Attributes (al);
                }

                /// <summary>
                /// Checks whether attribute target is valid for the current element
                /// </summary>
                public bool CheckTargets ()
                {
                        foreach (Attribute a in Attrs) {
                                if (!a.CheckTarget ())
                                        return false;
                        }
                        return true;
                }

                public Attribute Search (PredefinedAttribute t)
                {
                        foreach (Attribute a in Attrs) {
                                if (a.ResolveType () == t)
                                        return a;
                        }
                        return null;
                }

                /// <summary>
                /// Returns all attributes of type 't'. Use it when attribute is AllowMultiple = true
                /// </summary>
                public Attribute[] SearchMulti (PredefinedAttribute t)
                {
                        List<Attribute> ar = null;

                        foreach (Attribute a in Attrs) {
                                if (a.ResolveType () == t) {
                                        if (ar == null)
                                                ar = new List<Attribute> (Attrs.Count);
                                        ar.Add (a);
                                }
                        }

                        return ar == null ? null : ar.ToArray ();
                }

                public void Emit ()
                {
                        CheckTargets ();

                        Dictionary<Attribute, List<Attribute>> ld = Attrs.Count > 1 ? new Dictionary<Attribute, List<Attribute>> () : null;

                        foreach (Attribute a in Attrs)
                                a.Emit (ld);

                        if (ld == null || ld.Count == 0)
                                return;

                        foreach (var d in ld) {
                                if (d.Value == null)
                                        continue;

                                Attribute a = d.Key;

                                foreach (Attribute collision in d.Value)
                                        a.Report.SymbolRelatedToPreviousError (collision.Location, "");

                                a.Report.Error (579, a.Location, "The attribute `{0}' cannot be applied multiple times",
                                        a.GetSignatureForError ());
                        }
                }

                public bool Contains (PredefinedAttribute t)
                {
                        return Search (t) != null;
                }
        }

        public struct AttributeEncoder
        {
                public readonly BinaryWriter Stream;

                public AttributeEncoder (bool empty)
                {
                        if (empty) {
                                Stream = null;
                                return;
                        }

                        Stream = new BinaryWriter (new MemoryStream ());
                        const ushort version = 1;
                        Stream.Write (version);
                }

                public void Encode (string value)
                {
                        if (value == null)
                                throw new ArgumentNullException ();

                        var buf = Encoding.UTF8.GetBytes(value);
                        WriteCompressedValue (buf.Length);
                        Stream.Write (buf);
                }

                public void Encode (TypeSpec type)
                {
                        if (type == TypeManager.bool_type) {
                                Stream.Write ((byte) 0x02);
                        } else if (type == TypeManager.char_type) {
                                Stream.Write ((byte) 0x03);
                        } else if (type == TypeManager.sbyte_type) {
                                Stream.Write ((byte) 0x04);
                        } else if (type == TypeManager.byte_type) {
                                Stream.Write ((byte) 0x05);
                        } else if (type == TypeManager.short_type) {
                                Stream.Write ((byte) 0x06);
                        } else if (type == TypeManager.ushort_type) {
                                Stream.Write ((byte) 0x07);
                        } else if (type == TypeManager.int32_type) {
                                Stream.Write ((byte) 0x08);
                        } else if (type == TypeManager.uint32_type) {
                                Stream.Write ((byte) 0x09);
                        } else if (type == TypeManager.int64_type) {
                                Stream.Write ((byte) 0x0A);
                        } else if (type == TypeManager.uint64_type) {
                                Stream.Write ((byte) 0x0B);
                        } else if (type == TypeManager.float_type) {
                                Stream.Write ((byte) 0x0C);
                        } else if (type == TypeManager.double_type) {
                                Stream.Write ((byte) 0x0D);
                        } else if (type == TypeManager.string_type) {
                                Stream.Write ((byte) 0x0E);
                        } else if (type == TypeManager.type_type) {
                                Stream.Write ((byte) 0x50);
                        } else if (type == TypeManager.object_type) {
                                Stream.Write ((byte) 0x51);
                        } else if (TypeManager.IsEnumType (type)) {
                                Stream.Write ((byte) 0x55);
                                EncodeTypeName (type);
                        } else if (type.IsArray) {
                                Stream.Write ((byte) 0x1D);
                                Encode (TypeManager.GetElementType (type));
                        } else {
                                throw new NotImplementedException (type.ToString ());
                        }
                }

                public bool EncodeTypeName (TypeSpec type)
                {
//                      if (TypeManager.ContainsGenericParameters (type) && !TypeManager.IsGenericTypeDefinition (type))
//                              return false;

                        var old_type = type.GetMetaInfo ();
                        Encode (type.MemberDefinition.IsImported ? old_type.AssemblyQualifiedName : old_type.FullName);
                        return true;
                }

                void WriteCompressedValue (int value)
                {
                        if (value < 0x80) {
                                Stream.Write ((byte) value);
                                return;
                        }

                        if (value < 0x4000) {
                                Stream.Write ((byte) (0x80 | (value >> 8)));
                                Stream.Write ((byte) value);
                                return;
                        }

                        Stream.Write (value);
                }

                public byte[] ToArray ()
                {
                        return ((MemoryStream) Stream.BaseStream).ToArray ();
                }
        }


        /// <summary>
        /// Helper class for attribute verification routine.
        /// </summary>
        static class AttributeTester
        {
                public enum Result {
                        Ok,
                        RefOutArrayError,
                        ArrayArrayError
                }

                /// <summary>
                /// Returns true if parameters of two compared methods are CLS-Compliant.
                /// It tests differing only in ref or out, or in array rank.
                /// </summary>
                public static Result AreOverloadedMethodParamsClsCompliant (AParametersCollection pa, AParametersCollection pb) 
                {
                        TypeSpec [] types_a = pa.Types;
                        TypeSpec [] types_b = pb.Types;
                        if (types_a == null || types_b == null)
                                return Result.Ok;

                        if (types_a.Length != types_b.Length)
                                return Result.Ok;

                        Result result = Result.Ok;
                        for (int i = 0; i < types_b.Length; ++i) {
                                TypeSpec aType = types_a [i];
                                TypeSpec bType = types_b [i];

                                var ac_a = aType as ArrayContainer;
                                var ac_b = aType as ArrayContainer;

                                if (ac_a != null && ac_b != null) {
                                        if (ac_a.Rank != ac_b.Rank && ac_a.Element == ac_b.Element) {
                                                result = Result.RefOutArrayError;
                                                continue;
                                        }

                                        if (ac_a.Element.IsArray || ac_b.Element.IsArray) {
                                                result = Result.ArrayArrayError;
                                                continue;
                                        }
                                }

                                if (aType != bType)
                                        return Result.Ok;

                                const Parameter.Modifier out_ref_mod = (Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
                                if ((pa.FixedParameters[i].ModFlags & out_ref_mod) != (pb.FixedParameters[i].ModFlags & out_ref_mod))
                                        result = Result.RefOutArrayError;
                        }
                        return result;
                }

                public static void VerifyModulesClsCompliance (CompilerContext ctx)
                {
                        Module[] modules = GlobalRootNamespace.Instance.Modules;
                        if (modules == null)
                                return;

                        // The first module is generated assembly
                        for (int i = 1; i < modules.Length; ++i) {
                                Module module = modules [i];
                                if (!GetClsCompliantAttributeValue (module, null)) {
                                        ctx.Report.Error (3013, "Added modules must be marked with the CLSCompliant attribute " +
                                                      "to match the assembly", module.Name);
                                        return;
                                }
                        }
                }

                static bool GetClsCompliantAttributeValue (ICustomAttributeProvider attribute_provider, Assembly a) 
                {
                        object[] cls_attr = attribute_provider.GetCustomAttributes (typeof (CLSCompliantAttribute), false);
                        if (cls_attr.Length == 0) {
                                if (a == null)
                                        return false;

                                return GetClsCompliantAttributeValue (a, null);
                        }
                        
                        return ((CLSCompliantAttribute)cls_attr [0]).IsCompliant;
                }

                /// <summary>
                /// Common method for Obsolete error/warning reporting.
                /// </summary>
                public static void Report_ObsoleteMessage (ObsoleteAttribute oa, string member, Location loc, Report Report)
                {
                        if (oa.IsError) {
                                Report.Error (619, loc, "`{0}' is obsolete: `{1}'", member, oa.Message);
                                return;
                        }

                        if (oa.Message == null || oa.Message.Length == 0) {
                                Report.Warning (612, 1, loc, "`{0}' is obsolete", member);
                                return;
                        }
                        Report.Warning (618, 2, loc, "`{0}' is obsolete: `{1}'", member, oa.Message);
                }
        }

        public class PredefinedAttributes
        {
                // Core types
                public readonly PredefinedAttribute ParamArray;
                public readonly PredefinedAttribute Out;

                // Optional types
                public readonly PredefinedAttribute Obsolete;
                public readonly PredefinedAttribute DllImport;
                public readonly PredefinedAttribute MethodImpl;
                public readonly PredefinedAttribute MarshalAs;
                public readonly PredefinedAttribute In;
                public readonly PredefinedAttribute IndexerName;
                public readonly PredefinedAttribute Conditional;
                public readonly PredefinedAttribute CLSCompliant;
                public readonly PredefinedAttribute Security;
                public readonly PredefinedAttribute Required;
                public readonly PredefinedAttribute Guid;
                public readonly PredefinedAttribute AssemblyCulture;
                public readonly PredefinedAttribute AssemblyVersion;
                public readonly PredefinedAttribute AssemblyAlgorithmId;
                public readonly PredefinedAttribute AssemblyFlags;
                public readonly PredefinedAttribute ComImport;
                public readonly PredefinedAttribute CoClass;
                public readonly PredefinedAttribute AttributeUsage;
                public readonly PredefinedAttribute DefaultParameterValue;
                public readonly PredefinedAttribute OptionalParameter;

                // New in .NET 2.0
                public readonly PredefinedAttribute DefaultCharset;
                public readonly PredefinedAttribute TypeForwarder;
                public readonly PredefinedAttribute FixedBuffer;
                public readonly PredefinedAttribute CompilerGenerated;
                public readonly PredefinedAttribute InternalsVisibleTo;
                public readonly PredefinedAttribute RuntimeCompatibility;
                public readonly PredefinedAttribute DebuggerHidden;
                public readonly PredefinedAttribute UnsafeValueType;

                // New in .NET 3.5
                public readonly PredefinedAttribute Extension;

                // New in .NET 4.0
                public readonly PredefinedAttribute Dynamic;
                public readonly PredefinedAttribute DynamicTransform;   // DynamicAttribute with transform arguments

                //
                // Optional types which are used as types and for member lookup
                //
                public readonly PredefinedAttribute DefaultMember;
                public readonly PredefinedAttribute DecimalConstant;
                public readonly PredefinedAttribute StructLayout;
                public readonly PredefinedAttribute FieldOffset;

                public static PredefinedAttributes Get = new PredefinedAttributes ();

                private PredefinedAttributes ()
                {
                        ParamArray = new PredefinedAttribute ("System", "ParamArrayAttribute");
                        Out = new PredefinedAttribute ("System.Runtime.InteropServices", "OutAttribute");

                        Obsolete = new PredefinedAttribute ("System", "ObsoleteAttribute");
                        DllImport = new PredefinedAttribute ("System.Runtime.InteropServices", "DllImportAttribute");
                        MethodImpl = new PredefinedAttribute ("System.Runtime.CompilerServices", "MethodImplAttribute");
                        MarshalAs = new PredefinedAttribute ("System.Runtime.InteropServices", "MarshalAsAttribute");
                        In = new PredefinedAttribute ("System.Runtime.InteropServices", "InAttribute");
                        IndexerName = new PredefinedAttribute ("System.Runtime.CompilerServices", "IndexerNameAttribute");
                        Conditional = new PredefinedAttribute ("System.Diagnostics", "ConditionalAttribute");
                        CLSCompliant = new PredefinedAttribute ("System", "CLSCompliantAttribute");
                        Security = new PredefinedAttribute ("System.Security.Permissions", "SecurityAttribute");
                        Required = new PredefinedAttribute ("System.Runtime.CompilerServices", "RequiredAttributeAttribute");
                        Guid = new PredefinedAttribute ("System.Runtime.InteropServices", "GuidAttribute");
                        AssemblyCulture = new PredefinedAttribute ("System.Reflection", "AssemblyCultureAttribute");
                        AssemblyVersion = new PredefinedAttribute ("System.Reflection", "AssemblyVersionAttribute");
                        AssemblyAlgorithmId = new PredefinedAttribute ("System.Reflection", "AssemblyAlgorithmIdAttribute");
                        AssemblyFlags = new PredefinedAttribute ("System.Reflection", "AssemblyFlagsAttribute");
                        ComImport = new PredefinedAttribute ("System.Runtime.InteropServices", "ComImportAttribute");
                        CoClass = new PredefinedAttribute ("System.Runtime.InteropServices", "CoClassAttribute");
                        AttributeUsage = new PredefinedAttribute ("System", "AttributeUsageAttribute");
                        DefaultParameterValue = new PredefinedAttribute ("System.Runtime.InteropServices", "DefaultParameterValueAttribute");
                        OptionalParameter = new PredefinedAttribute ("System.Runtime.InteropServices", "OptionalAttribute");

                        DefaultCharset = new PredefinedAttribute ("System.Runtime.InteropServices", "DefaultCharSetAttribute");
                        TypeForwarder = new PredefinedAttribute ("System.Runtime.CompilerServices", "TypeForwardedToAttribute");
                        FixedBuffer = new PredefinedAttribute ("System.Runtime.CompilerServices", "FixedBufferAttribute");
                        CompilerGenerated = new PredefinedAttribute ("System.Runtime.CompilerServices", "CompilerGeneratedAttribute");
                        InternalsVisibleTo = new PredefinedAttribute ("System.Runtime.CompilerServices", "InternalsVisibleToAttribute");
                        RuntimeCompatibility = new PredefinedAttribute ("System.Runtime.CompilerServices", "RuntimeCompatibilityAttribute");
                        DebuggerHidden = new PredefinedAttribute ("System.Diagnostics", "DebuggerHiddenAttribute");
                        UnsafeValueType = new PredefinedAttribute ("System.Runtime.CompilerServices", "UnsafeValueTypeAttribute");

                        Extension = new PredefinedAttribute ("System.Runtime.CompilerServices", "ExtensionAttribute");

                        Dynamic = new PredefinedAttribute ("System.Runtime.CompilerServices", "DynamicAttribute");
                        DynamicTransform = new PredefinedAttribute ("System.Runtime.CompilerServices", "DynamicAttribute");

                        DefaultMember = new PredefinedAttribute ("System.Reflection", "DefaultMemberAttribute");
                        DecimalConstant = new PredefinedAttribute ("System.Runtime.CompilerServices", "DecimalConstantAttribute");
                        StructLayout = new PredefinedAttribute ("System.Runtime.InteropServices", "StructLayoutAttribute");
                        FieldOffset = new PredefinedAttribute ("System.Runtime.InteropServices", "FieldOffsetAttribute");
                }

                public void Initialize (CompilerContext ctx)
                {
                        foreach (FieldInfo fi in GetType ().GetFields (BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly)) {
                                ((PredefinedAttribute) fi.GetValue (this)).Initialize (ctx, true);
                        }
                }

                public static void Reset ()
                {
                        Get = new PredefinedAttributes ();
                }
        }

        public class PredefinedAttribute
        {
                TypeSpec type;
                CustomAttributeBuilder cab;
                MethodSpec ctor;
                readonly string ns, name;
                CompilerContext compiler;

                static readonly TypeSpec NotFound = InternalType.Null;

                public PredefinedAttribute (string ns, string name)
                {
                        this.ns = ns;
                        this.name = name;
                }

                public static bool operator == (TypeSpec type, PredefinedAttribute pa)
                {
                        return type == pa.type;
                }

                public static bool operator != (TypeSpec type, PredefinedAttribute pa)
                {
                        return type != pa.type;
                }

                public ConstructorInfo Constructor {
                        get { return ctor == null ? null : (ConstructorInfo) ctor.GetMetaInfo (); }
                }

                public override int GetHashCode ()
                {
                        return base.GetHashCode ();
                }

                public string GetSignatureForError ()
                {
                        return ns + "." + name;
                }

                public override bool Equals (object obj)
                {
                        throw new NotSupportedException ();
                }

                public void EmitAttribute (ConstructorBuilder builder)
                {
                        if (ResolveBuilder ())
                                builder.SetCustomAttribute (cab);
                }

                public void EmitAttribute (MethodBuilder builder)
                {
                        if (ResolveBuilder ())
                                builder.SetCustomAttribute (cab);
                }

                public void EmitAttribute (PropertyBuilder builder)
                {
                        if (ResolveBuilder ())
                                builder.SetCustomAttribute (cab);
                }

                public void EmitAttribute (FieldBuilder builder)
                {
                        if (ResolveBuilder ())
                                builder.SetCustomAttribute (cab);
                }

                public void EmitAttribute (TypeBuilder builder)
                {
                        if (ResolveBuilder ())
                                builder.SetCustomAttribute (cab);
                }

                public void EmitAttribute (AssemblyBuilder builder)
                {
                        if (ResolveBuilder ())
                                builder.SetCustomAttribute (cab);
                }

                public void EmitAttribute (ParameterBuilder builder)
                {
                        if (ResolveBuilder ())
                                builder.SetCustomAttribute (cab);
                }

                public bool IsDefined {
                        get { return type != null && type != NotFound; }
                }

                public void Initialize (CompilerContext ctx, bool canFail)
                {
                        this.compiler = ctx;
                        Resolve (canFail);
                }

                public bool Resolve (bool canFail)
                {
                        if (type != null) {
                                if (IsDefined)
                                        return true;
                                if (canFail)
                                        return false;
                        }

                        type = TypeManager.CoreLookupType (compiler, ns, name, MemberKind.Class, !canFail);
                        if (type == null) {
                                type = NotFound;
                                return false;
                        }

                        return true;
                }

                bool ResolveBuilder ()
                {
                        if (cab != null)
                                return true;

                        //
                        // Handle all parameter-less attributes as optional
                        //
                        if (!Resolve (true))
                                return false;

                        var ci = TypeManager.GetPredefinedConstructor (type, Location.Null, TypeSpec.EmptyTypes);
                        if (ci == null)
                                return false;

                        cab = new CustomAttributeBuilder ((ConstructorInfo) ci.GetMetaInfo (), new object[0]);
                        return true;
                }

                public bool ResolveConstructor (Location loc, params TypeSpec[] argType)
                {
                        if (ctor != null)
                                throw new InternalErrorException ("Predefined ctor redefined");

                        if (!Resolve (false))
                                return false;

                        ctor = TypeManager.GetPredefinedConstructor (type, loc, argType);
                        return ctor != null;
                }

                public TypeSpec Type {
                        get { return type; }
                }
        }
}