In ilasm/tests:

[mcs.git] / mcs / typemanager.cs

//
// typemanager.cs: C# type manager
//
// Author: Miguel de Icaza (miguel@gnu.org)
//         Ravi Pratap     (ravi@ximian.com)
//         Marek Safar     (marek.safar@seznam.cz)
//
// Licensed under the terms of the GNU GPL
//
// (C) 2001 Ximian, Inc (http://www.ximian.com)
//
//

//
// We will eventually remove the SIMPLE_SPEEDUP, and should never change 
// the behavior of the compilation.  This can be removed if we rework
// the code to get a list of namespaces available.
//
#define SIMPLE_SPEEDUP

using System;
using System.IO;
using System.Globalization;
using System.Collections;
using System.Reflection;
using System.Reflection.Emit;
using System.Text;
using System.Text.RegularExpressions;
using System.Runtime.CompilerServices;
using System.Diagnostics;

namespace Mono.CSharp {

public class TypeManager {
        //
        // A list of core types that the compiler requires or uses
        //
        static public Type object_type;
        static public Type value_type;
        static public Type string_type;
        static public Type int32_type;
        static public Type uint32_type;
        static public Type int64_type;
        static public Type uint64_type;
        static public Type float_type;
        static public Type double_type;
        static public Type char_type;
        static public Type char_ptr_type;
        static public Type short_type;
        static public Type decimal_type;
        static public Type bool_type;
        static public Type sbyte_type;
        static public Type byte_type;
        static public Type ushort_type;
        static public Type enum_type;
        static public Type delegate_type;
        static public Type multicast_delegate_type;
        static public Type void_type;
        static public Type null_type;
        static public Type enumeration_type;
        static public Type array_type;
        static public Type runtime_handle_type;
        static public Type icloneable_type;
        static public Type type_type;
        static public Type ienumerator_type;
        static public Type ienumerable_type;
        static public Type idisposable_type;
        static public Type iconvertible_type;
        static public Type default_member_type;
        static public Type iasyncresult_type;
        static public Type asynccallback_type;
        static public Type intptr_type;
        static public Type monitor_type;
        static public Type runtime_field_handle_type;
        static public Type runtime_argument_handle_type;
        static public Type attribute_type;
        static public Type attribute_usage_type;
        static public Type decimal_constant_attribute_type;
        static public Type dllimport_type;
        static public Type unverifiable_code_type;
        static public Type methodimpl_attr_type;
        static public Type marshal_as_attr_type;
        static public Type param_array_type;
        static public Type void_ptr_type;
        static public Type indexer_name_type;
        static public Type exception_type;
        static public Type invalid_operation_exception_type;
        static public Type not_supported_exception_type;
        static public Type obsolete_attribute_type;
        static public Type conditional_attribute_type;
        static public Type in_attribute_type;
        static public Type out_attribute_type;
        static public Type anonymous_method_type;
        static public Type cls_compliant_attribute_type;
        static public Type typed_reference_type;
        static public Type arg_iterator_type;
        static public Type mbr_type;
        static public Type struct_layout_attribute_type;
        static public Type field_offset_attribute_type;
        static public Type security_attr_type;
        static public Type required_attr_type;
        static public Type guid_attr_type;
        static public Type assembly_culture_attribute_type;
        static public Type coclass_attr_type;
        static public Type comimport_attr_type;

        /// 
        /// .NET 2.0
        ///
#if NET_2_0
        static internal Type runtime_compatibility_attr_type;
        static internal Type compiler_generated_attr_type;
        static internal Type fixed_buffer_attr_type;
        static internal Type default_charset_type;
#endif

        //
        // An empty array of types
        //
        static public Type [] NoTypes;
        static public TypeExpr [] NoTypeExprs;


        // 
        // Expressions representing the internal types.  Used during declaration
        // definition.
        //
        static public TypeExpr system_object_expr, system_string_expr; 
        static public TypeExpr system_boolean_expr, system_decimal_expr;
        static public TypeExpr system_single_expr, system_double_expr;
        static public TypeExpr system_sbyte_expr, system_byte_expr;
        static public TypeExpr system_int16_expr, system_uint16_expr;
        static public TypeExpr system_int32_expr, system_uint32_expr;
        static public TypeExpr system_int64_expr, system_uint64_expr;
        static public TypeExpr system_char_expr, system_void_expr;
        static public TypeExpr system_asynccallback_expr;
        static public TypeExpr system_iasyncresult_expr;
        static public TypeExpr system_valuetype_expr;
        static public TypeExpr system_intptr_expr;

        //
        // This is only used when compiling corlib
        //
        static public Type system_int32_type;
        static public Type system_array_type;
        static public Type system_type_type;
        static public Type system_assemblybuilder_type;
        static public MethodInfo system_int_array_get_length;
        static public MethodInfo system_int_array_get_rank;
        static public MethodInfo system_object_array_clone;
        static public MethodInfo system_int_array_get_length_int;
        static public MethodInfo system_int_array_get_lower_bound_int;
        static public MethodInfo system_int_array_get_upper_bound_int;
        static public MethodInfo system_void_array_copyto_array_int;

        
        //
        // Internal, not really used outside
        //
        static Type runtime_helpers_type;
        
        //
        // These methods are called by code generated by the compiler
        //
        static public MethodInfo string_concat_string_string;
        static public MethodInfo string_concat_string_string_string;
        static public MethodInfo string_concat_string_string_string_string;
        static public MethodInfo string_concat_string_dot_dot_dot;
        static public MethodInfo string_concat_object_object;
        static public MethodInfo string_concat_object_object_object;
        static public MethodInfo string_concat_object_dot_dot_dot;
        static public MethodInfo string_isinterneted_string;
        static public MethodInfo system_type_get_type_from_handle;
        static public MethodInfo bool_movenext_void;
        static public MethodInfo ienumerable_getenumerator_void;
        static public MethodInfo void_reset_void;
        static public MethodInfo void_dispose_void;
        static public MethodInfo void_monitor_enter_object;
        static public MethodInfo void_monitor_exit_object;
        static public MethodInfo void_initializearray_array_fieldhandle;
        static public MethodInfo int_getlength_int;
        static public MethodInfo delegate_combine_delegate_delegate;
        static public MethodInfo delegate_remove_delegate_delegate;
        static public MethodInfo int_get_offset_to_string_data;
        static public MethodInfo int_array_get_length;
        static public MethodInfo int_array_get_rank;
        static public MethodInfo object_array_clone;
        static public MethodInfo int_array_get_length_int;
        static public MethodInfo int_array_get_lower_bound_int;
        static public MethodInfo int_array_get_upper_bound_int;
        static public MethodInfo void_array_copyto_array_int;
        static public PropertyInfo ienumerator_getcurrent;
        
        //
        // The attribute constructors.
        //
        static public ConstructorInfo object_ctor;
        static public ConstructorInfo cons_param_array_attribute;
        static public ConstructorInfo void_decimal_ctor_five_args;
        static public ConstructorInfo void_decimal_ctor_int_arg;
        static public ConstructorInfo unverifiable_code_ctor;
        static public ConstructorInfo default_member_ctor;
        static public ConstructorInfo decimal_constant_attribute_ctor;
        static internal ConstructorInfo struct_layout_attribute_ctor;
        static public ConstructorInfo field_offset_attribute_ctor;
        
        ///
        /// A new in C# 2.0
        /// 
#if NET_2_0
        static internal CustomAttributeBuilder compiler_generated_attr;
        static internal ConstructorInfo fixed_buffer_attr_ctor;
#endif

        static PtrHashtable builder_to_declspace;

        static PtrHashtable builder_to_member_cache;

        // <remarks>
        //   Tracks the interfaces implemented by typebuilders.  We only
        //   enter those who do implement or or more interfaces
        // </remarks>
        static PtrHashtable builder_to_ifaces;

        // <remarks>
        //   Maps PropertyBuilder to a Type array that contains
        //   the arguments to the indexer
        // </remarks>
        static Hashtable indexer_arguments;

        // <remarks>
        //   Maps a MethodBase to its ParameterData (either InternalParameters or ReflectionParameters)
        // <remarks>
        static Hashtable method_params;

        // <remarks>
        //  A hash table from override methods to their base virtual method.
        // <remarks>
        static Hashtable method_overrides;

        // <remarks>
        //  Keeps track of methods
        // </remarks>

        static Hashtable builder_to_method;

        // <remarks>
        //  Contains all public types from referenced assemblies.
        //  This member is used only if CLS Compliance verification is required.
        // </remarks>
        public static Hashtable AllClsTopLevelTypes;

        static Hashtable fieldbuilders_to_fields;
        static Hashtable fields;

        struct Signature {
                public string name;
                public Type [] args;
        }
        
        public static void CleanUp ()
        {
                // Lets get everything clean so that we can collect before generating code
                builder_to_declspace = null;
                builder_to_member_cache = null;
                builder_to_ifaces = null;
                indexer_arguments = null;
                method_params = null;
                builder_to_method = null;
                
                fields = null;
                fieldbuilders_to_fields = null;
                events = null;
                priv_fields_events = null;
                type_hash = null;
                
                TypeHandle.CleanUp ();
        }

        /// <summary>
        ///   A filter for Findmembers that uses the Signature object to
        ///   extract objects
        /// </summary>
        static bool SignatureFilter (MemberInfo mi, object criteria)
        {
                Signature sig = (Signature) criteria;

                if (!(mi is MethodBase))
                        return false;
                
                if (mi.Name != sig.name)
                        return false;

                int count = sig.args.Length;
                
                if (mi is MethodBuilder || mi is ConstructorBuilder){
                        Type [] candidate_args = GetParameterData ((MethodBase) mi).Types;

                        if (candidate_args.Length != count)
                                return false;
                        
                        for (int i = 0; i < count; i++)
                                if (candidate_args [i] != sig.args [i])
                                        return false;
                        
                        return true;
                } else {
                        ParameterInfo [] pars = ((MethodBase) mi).GetParameters ();

                        if (pars.Length != count)
                                return false;

                        for (int i = 0; i < count; i++)
                                if (pars [i].ParameterType != sig.args [i])
                                        return false;
                        return true;
                }
        }

        // A delegate that points to the filter above.
        static MemberFilter signature_filter;

        //
        // These are expressions that represent some of the internal data types, used
        // elsewhere
        //
        static void InitExpressionTypes ()
        {
                system_object_expr  = new TypeLookupExpression ("System.Object");
                system_string_expr  = new TypeLookupExpression ("System.String");
                system_boolean_expr = new TypeLookupExpression ("System.Boolean");
                system_decimal_expr = new TypeLookupExpression ("System.Decimal");
                system_single_expr  = new TypeLookupExpression ("System.Single");
                system_double_expr  = new TypeLookupExpression ("System.Double");
                system_sbyte_expr   = new TypeLookupExpression ("System.SByte");
                system_byte_expr    = new TypeLookupExpression ("System.Byte");
                system_int16_expr   = new TypeLookupExpression ("System.Int16");
                system_uint16_expr  = new TypeLookupExpression ("System.UInt16");
                system_int32_expr   = new TypeLookupExpression ("System.Int32");
                system_uint32_expr  = new TypeLookupExpression ("System.UInt32");
                system_int64_expr   = new TypeLookupExpression ("System.Int64");
                system_uint64_expr  = new TypeLookupExpression ("System.UInt64");
                system_char_expr    = new TypeLookupExpression ("System.Char");
                system_void_expr    = new TypeLookupExpression ("System.Void");
                system_asynccallback_expr = new TypeLookupExpression ("System.AsyncCallback");
                system_iasyncresult_expr = new TypeLookupExpression ("System.IAsyncResult");
                system_valuetype_expr  = new TypeLookupExpression ("System.ValueType");
                system_intptr_expr  = new TypeLookupExpression ("System.IntPtr");
        }

        static TypeManager ()
        {
                Reset ();

                signature_filter = new MemberFilter (SignatureFilter);
                InitExpressionTypes ();
        }

        static public void Reset ()
        {
                builder_to_declspace = new PtrHashtable ();
                builder_to_member_cache = new PtrHashtable ();
                builder_to_method = new PtrHashtable ();
                method_params = new PtrHashtable ();
                method_overrides = new PtrHashtable ();
                indexer_arguments = new PtrHashtable ();
                builder_to_ifaces = new PtrHashtable ();
                
                NoTypes = new Type [0];
                NoTypeExprs = new TypeExpr [0];

                fieldbuilders_to_fields = new Hashtable ();
                fields = new Hashtable ();
                type_hash = new DoubleHash ();
        }

        public static void AddUserType (DeclSpace ds)
        {
                builder_to_declspace.Add (ds.TypeBuilder, ds);
        }

        //
        // This entry point is used by types that we define under the covers
        // 
        public static void RegisterBuilder (Type tb, Type [] ifaces)
        {
                if (ifaces != null)
                        builder_to_ifaces [tb] = ifaces;
        }       

        public static void AddMethod (MethodBase builder, IMethodData method)
        {
                builder_to_method.Add (builder, method);
                method_params.Add (builder, method.ParameterInfo);
        }

        public static IMethodData GetMethod (MethodBase builder)
        {
                return (IMethodData) builder_to_method [builder];
        }

        /// <summary>
        ///   Returns the DeclSpace whose Type is `t' or null if there is no
        ///   DeclSpace for `t' (ie, the Type comes from a library)
        /// </summary>
        public static DeclSpace LookupDeclSpace (Type t)
        {
                return builder_to_declspace [t] as DeclSpace;
        }

        /// <summary>
        ///   Returns the TypeContainer whose Type is `t' or null if there is no
        ///   TypeContainer for `t' (ie, the Type comes from a library)
        /// </summary>
        public static TypeContainer LookupTypeContainer (Type t)
        {
                return builder_to_declspace [t] as TypeContainer;
        }

        public static MemberCache LookupMemberCache (Type t)
        {
                if (t is TypeBuilder) {
                        IMemberContainer container = builder_to_declspace [t] as IMemberContainer;
                        if (container != null)
                                return container.MemberCache;
                }

                return TypeHandle.GetMemberCache (t);
        }

        public static MemberCache LookupBaseInterfacesCache (Type t)
        {
                Type [] ifaces = t.GetInterfaces ();

                if (ifaces != null && ifaces.Length == 1)
                        return LookupMemberCache (ifaces [0]);

                // TODO: the builder_to_member_cache should be indexed by 'ifaces', not 't'
                MemberCache cache = builder_to_member_cache [t] as MemberCache;
                if (cache != null)
                        return cache;

                cache = new MemberCache (ifaces);
                builder_to_member_cache.Add (t, cache);
                return cache;
        }

        public static TypeContainer LookupInterface (Type t)
        {
                TypeContainer tc = (TypeContainer) builder_to_declspace [t];
                if ((tc == null) || (tc.Kind != Kind.Interface))
                        return null;

                return tc;
        }

        public static Delegate LookupDelegate (Type t)
        {
                return builder_to_declspace [t] as Delegate;
        }

        public static Class LookupClass (Type t)
        {
                return (Class) builder_to_declspace [t];
        }

        //
        // We use this hash for multiple kinds of constructed types:
        //
        //    (T, "&")  Given T, get T &
        //    (T, "*")  Given T, get T *
        //    (T, "[]") Given T and a array dimension, get T []
        //    (T, X)    Given a type T and a simple name X, get the type T+X
        //
        // Accessibility tests, if necessary, should be done by the user
        //
        static DoubleHash type_hash = new DoubleHash ();

        //
        // Gets the reference to T version of the Type (T&)
        //
        public static Type GetReferenceType (Type t)
        {
                return GetConstructedType (t, "&");
        }

        //
        // Gets the pointer to T version of the Type  (T*)
        //
        public static Type GetPointerType (Type t)
        {
                return GetConstructedType (t, "*");
        }

        public static Type GetConstructedType (Type t, string dim)
        {
                object ret = null;
                if (!type_hash.Lookup (t, dim, out ret)) {
                        ret = t.Module.GetType (t.ToString () + dim);
                        type_hash.Insert (t, dim, ret);
                }
                return (Type) ret;
        }

        public static Type GetNestedType (Type t, string name)
        {
                object ret = null;
                if (!type_hash.Lookup (t, name, out ret)) {
                        ret = t.GetNestedType (name,
                               BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.DeclaredOnly);
                        type_hash.Insert (t, name, ret);
                }
                return (Type) ret;
        }

        /// <summary>
        /// Fills static table with exported types from all referenced assemblies.
        /// This information is required for CLS Compliance tests.
        /// </summary>
        public static void LoadAllImportedTypes ()
        {
                AllClsTopLevelTypes = new Hashtable (1500);
                foreach (Assembly a in RootNamespace.Global.Assemblies) {
                        foreach (Type t in a.GetExportedTypes ()) {
                                AllClsTopLevelTypes [t.FullName.ToLower (System.Globalization.CultureInfo.InvariantCulture)] = null;
                        }
                }
        }

        public static bool NamespaceClash (string name, Location loc)
        {
                if (! RootNamespace.Global.IsNamespace (name))
                        return false;

                Report.Error (519, loc, String.Format ("`{0}' clashes with a predefined namespace", name));
                return true;
        }

        /// <summary>
        ///   Returns the C# name of a type if possible, or the full type name otherwise
        /// </summary>
        static public string CSharpName (Type t)
        {
                return Regex.Replace (t.FullName, 
                        @"^System\." +
                        @"(Int32|UInt32|Int16|UInt16|Int64|UInt64|" +
                        @"Single|Double|Char|Decimal|Byte|SByte|Object|" +
                        @"Boolean|String|Void|Null)" +
                        @"(\W+|\b)", 
                        new MatchEvaluator (CSharpNameMatch)).Replace ('+', '.');
        }       

        static public string CSharpName (Type[] types)
        {
                StringBuilder sb = new StringBuilder ();
                foreach (Type t in types) {
                        sb.Append (CSharpName (t));
                        sb.Append (',');
                }
                sb.Remove (sb.Length - 1, 1);
                return sb.ToString ();
        }
        
        static String CSharpNameMatch (Match match) 
        {
                string s = match.Groups [1].Captures [0].Value;
                return s.ToLower ().
                Replace ("int32", "int").
                Replace ("uint32", "uint").
                Replace ("int16", "short").
                Replace ("uint16", "ushort").
                Replace ("int64", "long").
                Replace ("uint64", "ulong").
                Replace ("single", "float").
                Replace ("boolean", "bool")
                + match.Groups [2].Captures [0].Value;
        }

        /// <summary>
        ///  Returns the signature of the method with full namespace classification
        /// </summary>
        static public string GetFullNameSignature (MemberInfo mi)
        {
                PropertyInfo pi = mi as PropertyInfo;
                if (pi != null) {
                        MethodBase pmi = pi.GetGetMethod ();
                        if (pmi == null)
                                pmi = pi.GetSetMethod ();
                        if (GetParameterData (pmi).Count > 0)
                                mi = pmi;
                }
                return (mi is MethodBase)
                        ? CSharpSignature (mi as MethodBase) 
                        : CSharpName (mi.DeclaringType) + '.' + mi.Name;
        }

        /// <summary>
        /// When we need to report accessors as well
        /// </summary>
        static public string CSharpSignature (MethodBase mb)
        {
                return CSharpSignature (mb, false);
        }

        /// <summary>
        ///   Returns the signature of the method
        /// </summary>
        static public string CSharpSignature (MethodBase mb, bool show_accessor)
        {
                StringBuilder sig = new StringBuilder (CSharpName (mb.DeclaringType));
                sig.Append ('.');

                ParameterData iparams = GetParameterData (mb);
                string parameters = iparams.GetSignatureForError ();
                string accessor = "";

                // Is property
                if (mb.IsSpecialName) {
                        Operator.OpType ot = Operator.GetOperatorType (mb.Name);
                        if (ot != Operator.OpType.TOP) {
                                sig.Append ("operator ");
                                sig.Append (Operator.GetName (ot));
                                sig.Append (parameters);
                                return sig.ToString ();
                        }

                        if (mb.Name.StartsWith ("get_") || mb.Name.StartsWith ("set_")) {
                                accessor = mb.Name.Substring (0, 3);
                        }
                }

                // Is indexer
                if (mb.IsSpecialName && !mb.IsConstructor) {
                        if (iparams.Count > (mb.Name.StartsWith ("get_") ? 0 : 1)) {
                                sig.Append ("this[");
                                if (show_accessor) {
                                        sig.Append (parameters.Substring (1, parameters.Length - 2));
                                }
                                else {
                                        int before_ret_val = parameters.LastIndexOf (',');
                                        if (before_ret_val < 0)
                                                sig.Append (parameters.Substring (1, parameters.Length - 2));
                                        else
                                                sig.Append (parameters.Substring (1, before_ret_val - 1));
                                }
                                sig.Append (']');
                        } else {
                                sig.Append (mb.Name.Substring (4));
                        }
                } else {
                        if (mb.Name == ".ctor")
                                sig.Append (mb.DeclaringType.Name);
                        else
                                sig.Append (mb.Name);

                        sig.Append (parameters);
                }

                if (show_accessor && accessor.Length > 0) {
                        sig.Append ('.');
                        sig.Append (accessor);
                }

                return sig.ToString ();
        }

        static public string CSharpSignature (EventInfo ei)
        {
                return CSharpName (ei.DeclaringType) + '.' + ei.Name;
        }

        /// <summary>
        ///   Looks up a type, and aborts if it is not found.  This is used
        ///   by types required by the compiler
        /// </summary>
        static Type CoreLookupType (string ns_name, string name)
        {
                Namespace ns = RootNamespace.Global.GetNamespace (ns_name, true);
                FullNamedExpression fne = ns.Lookup (RootContext.Tree.Types, name, Location.Null);
                Type t = fne == null ? null : fne.Type;
                if (t == null)
                        Report.Error (518, "The predefined type `" + name + "' is not defined or imported");
                return t;
        }

        /// <summary>
        ///   Returns the MethodInfo for a method named `name' defined
        ///   in type `t' which takes arguments of types `args'
        /// </summary>
        static MethodInfo GetMethod (Type t, string name, Type [] args, bool is_private, bool report_errors)
        {
                MemberList list;
                Signature sig;
                BindingFlags flags = instance_and_static | BindingFlags.Public;

                sig.name = name;
                sig.args = args;

                if (is_private)
                        flags |= BindingFlags.NonPublic;

                list = FindMembers (t, MemberTypes.Method, flags, signature_filter, sig);
                if (list.Count == 0) {
                        if (report_errors)
                                Report.Error (-19, "Can not find the core function `" + name + "'");
                        return null;
                }

                MethodInfo mi = list [0] as MethodInfo;
                if (mi == null) {
                        if (report_errors)
                                Report.Error (-19, "Can not find the core function `" + name + "'");
                        return null;
                }

                return mi;
        }

        static MethodInfo GetMethod (Type t, string name, Type [] args, bool report_errors)
        {
                return GetMethod (t, name, args, false, report_errors);
        }

        static MethodInfo GetMethod (Type t, string name, Type [] args)
        {
                return GetMethod (t, name, args, true);
        }

        /// <summary>
        ///   Returns the PropertyInfo for a property named `name' defined
        ///   in type `t'
        /// </summary>
        static PropertyInfo GetProperty (Type t, string name)
        {
                MemberList list = FindMembers (t, MemberTypes.Property, BindingFlags.Public |
                                    BindingFlags.Instance, Type.FilterName, name);
                if (list.Count == 0) {
                        Report.Error (-19, "Can not find the core property `" + name + "'");
                        return null;
                }

                PropertyInfo pi = list [0] as PropertyInfo;
                if (pi == null) {
                        Report.Error (-19, "Can not find the core function `" + name + "'");
                        return null;
                }

                return pi;
        }

        /// <summary>
        ///    Returns the ConstructorInfo for "args"
        /// </summary>
        public static ConstructorInfo GetConstructor (Type t, Type [] args)
        {
                MemberList list;
                Signature sig;

                sig.name = ".ctor";
                sig.args = args;
                
                list = FindMembers (t, MemberTypes.Constructor,
                                    instance_and_static | BindingFlags.Public | BindingFlags.DeclaredOnly,
                                    signature_filter, sig);
                if (list.Count == 0){
                        Report.Error (-19, "Can not find the core constructor for type `" + t.Name + "'");
                        return null;
                }

                ConstructorInfo ci = list [0] as ConstructorInfo;
                if (ci == null){
                        Report.Error (-19, "Can not find the core constructor for type `" + t.Name + "'");
                        return null;
                }

                return ci;
        }

        public static void InitEnumUnderlyingTypes ()
        {

                int32_type    = CoreLookupType ("System", "Int32");
                int64_type    = CoreLookupType ("System", "Int64");
                uint32_type   = CoreLookupType ("System", "UInt32"); 
                uint64_type   = CoreLookupType ("System", "UInt64"); 
                byte_type     = CoreLookupType ("System", "Byte");
                sbyte_type    = CoreLookupType ("System", "SByte");
                short_type    = CoreLookupType ("System", "Int16");
                ushort_type   = CoreLookupType ("System", "UInt16");
        }
        
        /// <remarks>
        ///   The types have to be initialized after the initial
        ///   population of the type has happened (for example, to
        ///   bootstrap the corlib.dll
        /// </remarks>
        public static void InitCoreTypes ()
        {
                object_type   = CoreLookupType ("System", "Object");
                value_type    = CoreLookupType ("System", "ValueType");

                InitEnumUnderlyingTypes ();

                char_type     = CoreLookupType ("System", "Char");
                string_type   = CoreLookupType ("System", "String");
                float_type    = CoreLookupType ("System", "Single");
                double_type   = CoreLookupType ("System", "Double");
                char_ptr_type = GetPointerType (char_type);
                decimal_type  = CoreLookupType ("System", "Decimal");
                bool_type     = CoreLookupType ("System", "Boolean");
                enum_type     = CoreLookupType ("System", "Enum");

                multicast_delegate_type = CoreLookupType ("System", "MulticastDelegate");
                delegate_type           = CoreLookupType ("System", "Delegate");

                array_type    = CoreLookupType ("System", "Array");
                void_type     = CoreLookupType ("System", "Void");
                type_type     = CoreLookupType ("System", "Type");

                runtime_field_handle_type = CoreLookupType ("System", "RuntimeFieldHandle");
                runtime_argument_handle_type = CoreLookupType ("System", "RuntimeArgumentHandle");
                runtime_helpers_type = CoreLookupType ("System.Runtime.CompilerServices", "RuntimeHelpers");
                default_member_type  = CoreLookupType ("System.Reflection", "DefaultMemberAttribute");
                runtime_handle_type  = CoreLookupType ("System", "RuntimeTypeHandle");
                asynccallback_type   = CoreLookupType ("System", "AsyncCallback");
                iasyncresult_type    = CoreLookupType ("System", "IAsyncResult");
                ienumerator_type     = CoreLookupType ("System.Collections", "IEnumerator");
                ienumerable_type     = CoreLookupType ("System.Collections", "IEnumerable");
                idisposable_type     = CoreLookupType ("System", "IDisposable");
                icloneable_type      = CoreLookupType ("System", "ICloneable");
                iconvertible_type    = CoreLookupType ("System", "IConvertible");
                monitor_type         = CoreLookupType ("System.Threading", "Monitor");
                intptr_type          = CoreLookupType ("System", "IntPtr");

                attribute_type       = CoreLookupType ("System", "Attribute");
                attribute_usage_type = CoreLookupType ("System", "AttributeUsageAttribute");
                dllimport_type       = CoreLookupType ("System.Runtime.InteropServices", "DllImportAttribute");
                methodimpl_attr_type = CoreLookupType ("System.Runtime.CompilerServices", "MethodImplAttribute");
                marshal_as_attr_type = CoreLookupType ("System.Runtime.InteropServices", "MarshalAsAttribute");
                param_array_type     = CoreLookupType ("System", "ParamArrayAttribute");
                in_attribute_type    = CoreLookupType ("System.Runtime.InteropServices", "InAttribute");
                out_attribute_type   = CoreLookupType ("System.Runtime.InteropServices", "OutAttribute");
                typed_reference_type = CoreLookupType ("System", "TypedReference");
                arg_iterator_type    = CoreLookupType ("System", "ArgIterator");
                mbr_type             = CoreLookupType ("System", "MarshalByRefObject");
                decimal_constant_attribute_type = CoreLookupType ("System.Runtime.CompilerServices", "DecimalConstantAttribute");

                unverifiable_code_type= CoreLookupType ("System.Security", "UnverifiableCodeAttribute");

                void_ptr_type         = GetPointerType (void_type);

                indexer_name_type     = CoreLookupType ("System.Runtime.CompilerServices", "IndexerNameAttribute");

                exception_type        = CoreLookupType ("System", "Exception");
                invalid_operation_exception_type = CoreLookupType ("System", "InvalidOperationException");
                not_supported_exception_type = CoreLookupType ("System", "NotSupportedException");

                //
                // Attribute types
                //
                obsolete_attribute_type = CoreLookupType ("System", "ObsoleteAttribute");
                conditional_attribute_type = CoreLookupType ("System.Diagnostics", "ConditionalAttribute");
                cls_compliant_attribute_type = CoreLookupType ("System", "CLSCompliantAttribute");
                struct_layout_attribute_type = CoreLookupType ("System.Runtime.InteropServices", "StructLayoutAttribute");
                field_offset_attribute_type = CoreLookupType ("System.Runtime.InteropServices", "FieldOffsetAttribute");
                security_attr_type = CoreLookupType ("System.Security.Permissions", "SecurityAttribute");
                required_attr_type = CoreLookupType ("System.Runtime.CompilerServices", "RequiredAttributeAttribute");
                guid_attr_type = CoreLookupType ("System.Runtime.InteropServices", "GuidAttribute");
                assembly_culture_attribute_type = CoreLookupType ("System.Reflection", "AssemblyCultureAttribute");
                comimport_attr_type = CoreLookupType ("System.Runtime.InteropServices", "ComImportAttribute");
                coclass_attr_type = CoreLookupType ("System.Runtime.InteropServices", "CoClassAttribute");

                //
                // .NET 2.0
                //
#if NET_2_0
                compiler_generated_attr_type = CoreLookupType ("System.Runtime.CompilerServices", "CompilerGeneratedAttribute");
                fixed_buffer_attr_type = CoreLookupType ("System.Runtime.CompilerServices", "FixedBufferAttribute");
                default_charset_type = CoreLookupType ("System.Runtime.InteropServices", "DefaultCharSetAttribute");
                runtime_compatibility_attr_type = CoreLookupType ("System.Runtime.CompilerServices", "RuntimeCompatibilityAttribute");
#endif
                //
                // When compiling corlib, store the "real" types here.
                //
                if (!RootContext.StdLib) {
                        system_int32_type = typeof (System.Int32);
                        system_array_type = typeof (System.Array);
                        system_type_type = typeof (System.Type);
                        system_assemblybuilder_type = typeof (System.Reflection.Emit.AssemblyBuilder);

                        Type [] void_arg = {  };
                        system_int_array_get_length = GetMethod (
                                system_array_type, "get_Length", void_arg);
                        system_int_array_get_rank = GetMethod (
                                system_array_type, "get_Rank", void_arg);
                        system_object_array_clone = GetMethod (
                                system_array_type, "Clone", void_arg);

                        Type [] system_int_arg = { system_int32_type };
                        system_int_array_get_length_int = GetMethod (
                                system_array_type, "GetLength", system_int_arg);
                        system_int_array_get_upper_bound_int = GetMethod (
                                system_array_type, "GetUpperBound", system_int_arg);
                        system_int_array_get_lower_bound_int = GetMethod (
                                system_array_type, "GetLowerBound", system_int_arg);

                        Type [] system_array_int_arg = { system_array_type, system_int32_type };
                        system_void_array_copyto_array_int = GetMethod (
                                system_array_type, "CopyTo", system_array_int_arg);

                        Type [] system_3_type_arg = {
                                system_type_type, system_type_type, system_type_type };
                        Type [] system_4_type_arg = {
                                system_type_type, system_type_type, system_type_type, system_type_type };

                        MethodInfo set_corlib_type_builders = GetMethod (
                                system_assemblybuilder_type, "SetCorlibTypeBuilders",
                                system_4_type_arg, true, false);

                        if (set_corlib_type_builders != null) {
                                object[] args = new object [4];
                                args [0] = object_type;
                                args [1] = value_type;
                                args [2] = enum_type;
                                args [3] = void_type;
                                
                                set_corlib_type_builders.Invoke (CodeGen.Assembly.Builder, args);
                        } else {
                                // Compatibility for an older version of the class libs.
                                set_corlib_type_builders = GetMethod (
                                        system_assemblybuilder_type, "SetCorlibTypeBuilders",
                                        system_3_type_arg, true, true);

                                if (set_corlib_type_builders == null) {
                                        Report.Error (-26, "Corlib compilation is not supported in Microsoft.NET due to bugs in it");
                                        return;
                                }

                                object[] args = new object [3];
                                args [0] = object_type;
                                args [1] = value_type;
                                args [2] = enum_type;
                                
                                set_corlib_type_builders.Invoke (CodeGen.Assembly.Builder, args);
                        }
                }

                system_object_expr.Type = object_type;
                system_string_expr.Type = string_type;
                system_boolean_expr.Type = bool_type;
                system_decimal_expr.Type = decimal_type;
                system_single_expr.Type = float_type;
                system_double_expr.Type = double_type;
                system_sbyte_expr.Type = sbyte_type;
                system_byte_expr.Type = byte_type;
                system_int16_expr.Type = short_type;
                system_uint16_expr.Type = ushort_type;
                system_int32_expr.Type = int32_type;
                system_uint32_expr.Type = uint32_type;
                system_int64_expr.Type = int64_type;
                system_uint64_expr.Type = uint64_type;
                system_char_expr.Type = char_type;
                system_void_expr.Type = void_type;
                system_asynccallback_expr.Type = asynccallback_type;
                system_iasyncresult_expr.Type = iasyncresult_type;
                system_valuetype_expr.Type = value_type;

                //
                // These are only used for compare purposes
                //
                anonymous_method_type = typeof (AnonymousMethod);
                null_type = typeof (NullType);
        }

        //
        // The helper methods that are used by the compiler
        //
        public static void InitCodeHelpers ()
        {
                //
                // Now load the default methods that we use.
                //
                Type [] string_string = { string_type, string_type };
                string_concat_string_string = GetMethod (
                        string_type, "Concat", string_string);
                Type [] string_string_string = { string_type, string_type, string_type };
                string_concat_string_string_string = GetMethod (
                        string_type, "Concat", string_string_string);
                Type [] string_string_string_string = { string_type, string_type, string_type, string_type };
                string_concat_string_string_string_string = GetMethod (
                        string_type, "Concat", string_string_string_string);
                Type[] params_string = { GetConstructedType (string_type, "[]") };
                string_concat_string_dot_dot_dot = GetMethod (
                        string_type, "Concat", params_string);

                Type [] object_object = { object_type, object_type };
                string_concat_object_object = GetMethod (
                        string_type, "Concat", object_object);
                Type [] object_object_object = { object_type, object_type, object_type };
                string_concat_object_object_object = GetMethod (
                        string_type, "Concat", object_object_object);
                Type[] params_object = { GetConstructedType (object_type, "[]") };
                string_concat_object_dot_dot_dot = GetMethod (
                        string_type, "Concat", params_object);

                Type [] string_ = { string_type };
                string_isinterneted_string = GetMethod (
                        string_type, "IsInterned", string_);
                
                Type [] runtime_type_handle = { runtime_handle_type };
                system_type_get_type_from_handle = GetMethod (
                        type_type, "GetTypeFromHandle", runtime_type_handle);

                Type [] delegate_delegate = { delegate_type, delegate_type };
                delegate_combine_delegate_delegate = GetMethod (
                                delegate_type, "Combine", delegate_delegate);

                delegate_remove_delegate_delegate = GetMethod (
                                delegate_type, "Remove", delegate_delegate);

                //
                // Void arguments
                //
                Type [] void_arg = {  };
                ienumerator_getcurrent = GetProperty (
                        ienumerator_type, "Current");
                bool_movenext_void = GetMethod (
                        ienumerator_type, "MoveNext", void_arg);
                void_reset_void = GetMethod (
                        ienumerator_type, "Reset", void_arg);
                void_dispose_void = GetMethod (
                        idisposable_type, "Dispose", void_arg);
                int_get_offset_to_string_data = GetMethod (
                        runtime_helpers_type, "get_OffsetToStringData", void_arg);
                int_array_get_length = GetMethod (
                        array_type, "get_Length", void_arg);
                int_array_get_rank = GetMethod (
                        array_type, "get_Rank", void_arg);
                ienumerable_getenumerator_void = GetMethod (
                        ienumerable_type, "GetEnumerator", void_arg);
                
                //
                // Int32 arguments
                //
                Type [] int_arg = { int32_type };
                int_array_get_length_int = GetMethod (
                        array_type, "GetLength", int_arg);
                int_array_get_upper_bound_int = GetMethod (
                        array_type, "GetUpperBound", int_arg);
                int_array_get_lower_bound_int = GetMethod (
                        array_type, "GetLowerBound", int_arg);

                //
                // System.Array methods
                //
                object_array_clone = GetMethod (
                        array_type, "Clone", void_arg);
                Type [] array_int_arg = { array_type, int32_type };
                void_array_copyto_array_int = GetMethod (
                        array_type, "CopyTo", array_int_arg);
                
                //
                // object arguments
                //
                Type [] object_arg = { object_type };
                void_monitor_enter_object = GetMethod (
                        monitor_type, "Enter", object_arg);
                void_monitor_exit_object = GetMethod (
                        monitor_type, "Exit", object_arg);

                Type [] array_field_handle_arg = { array_type, runtime_field_handle_type };
                
                void_initializearray_array_fieldhandle = GetMethod (
                        runtime_helpers_type, "InitializeArray", array_field_handle_arg);

                //
                // Array functions
                //
                int_getlength_int = GetMethod (
                        array_type, "GetLength", int_arg);

                //
                // Decimal constructors
                //
                Type [] dec_arg = { int32_type, int32_type, int32_type, bool_type, byte_type };
                void_decimal_ctor_five_args = GetConstructor (
                        decimal_type, dec_arg);
                
                void_decimal_ctor_int_arg = GetConstructor (decimal_type, int_arg);

                //
                // Attributes
                //
                cons_param_array_attribute = GetConstructor (param_array_type, void_arg);
                unverifiable_code_ctor = GetConstructor (unverifiable_code_type, void_arg);
                default_member_ctor = GetConstructor (default_member_type, string_);

                Type[] short_arg = { short_type };
                struct_layout_attribute_ctor = GetConstructor (struct_layout_attribute_type, short_arg);

                decimal_constant_attribute_ctor = GetConstructor (decimal_constant_attribute_type, new Type []
                        { byte_type, byte_type, uint32_type, uint32_type, uint32_type } );

                field_offset_attribute_ctor = GetConstructor (field_offset_attribute_type, new Type []
                        { int32_type });

                //
                // .NET 2.0 types
                //
#if NET_2_0
                compiler_generated_attr = new CustomAttributeBuilder (
                        GetConstructor (compiler_generated_attr_type, void_arg), new object[0]);

                Type[] type_int_arg = { type_type, int32_type };
                fixed_buffer_attr_ctor = GetConstructor (fixed_buffer_attr_type, type_int_arg);
#endif

                // Object
                object_ctor = GetConstructor (object_type, void_arg);

        }

        const BindingFlags instance_and_static = BindingFlags.Static | BindingFlags.Instance;

        /// <remarks>
        ///   This is the "old", non-cache based FindMembers() function.  We cannot use
        ///   the cache here because there is no member name argument.
        /// </remarks>
        public static MemberList FindMembers (Type t, MemberTypes mt, BindingFlags bf,
                                              MemberFilter filter, object criteria)
        {
                DeclSpace decl = (DeclSpace) builder_to_declspace [t];

                //
                // `builder_to_declspace' contains all dynamic types.
                //
                if (decl != null) {
                        MemberList list;
                        Timer.StartTimer (TimerType.FindMembers);
                        list = decl.FindMembers (mt, bf, filter, criteria);
                        Timer.StopTimer (TimerType.FindMembers);
                        return list;
                }

                //
                // We have to take care of arrays specially, because GetType on
                // a TypeBuilder array will return a Type, not a TypeBuilder,
                // and we can not call FindMembers on this type.
                //
                if (TypeManager.IsSubclassOf (t, TypeManager.array_type))
                        return new MemberList (TypeManager.array_type.FindMembers (mt, bf, filter, criteria));

                //
                // Since FindMembers will not lookup both static and instance
                // members, we emulate this behaviour here.
                //
                if ((bf & instance_and_static) == instance_and_static){
                        MemberInfo [] i_members = t.FindMembers (
                                mt, bf & ~BindingFlags.Static, filter, criteria);

                        int i_len = i_members.Length;
                        if (i_len == 1){
                                MemberInfo one = i_members [0];

                                //
                                // If any of these are present, we are done!
                                //
                                if ((one is Type) || (one is EventInfo) || (one is FieldInfo))
                                        return new MemberList (i_members);
                        }
                                
                        MemberInfo [] s_members = t.FindMembers (
                                mt, bf & ~BindingFlags.Instance, filter, criteria);

                        int s_len = s_members.Length;
                        if (i_len > 0 || s_len > 0)
                                return new MemberList (i_members, s_members);
                        else {
                                if (i_len > 0)
                                        return new MemberList (i_members);
                                else
                                        return new MemberList (s_members);
                        }
                }

                return new MemberList (t.FindMembers (mt, bf, filter, criteria));
        }


        /// <summary>
        ///   This method is only called from within MemberLookup.  It tries to use the member
        ///   cache if possible and falls back to the normal FindMembers if not.  The `used_cache'
        ///   flag tells the caller whether we used the cache or not.  If we used the cache, then
        ///   our return value will already contain all inherited members and the caller don't need
        ///   to check base classes and interfaces anymore.
        /// </summary>
        private static MemberInfo [] MemberLookup_FindMembers (Type t, MemberTypes mt, BindingFlags bf,
                                                            string name, out bool used_cache)
        {
                MemberCache cache;

                //
                // We have to take care of arrays specially, because GetType on
                // a TypeBuilder array will return a Type, not a TypeBuilder,
                // and we can not call FindMembers on this type.
                //
                if (t == TypeManager.array_type || t.IsSubclassOf (TypeManager.array_type)) {
                        used_cache = true;
                        return TypeHandle.ArrayType.MemberCache.FindMembers (
                                mt, bf, name, FilterWithClosure_delegate, null);
                }

                //
                // If this is a dynamic type, it's always in the `builder_to_declspace' hash table
                // and we can ask the DeclSpace for the MemberCache.
                //
                if (t is TypeBuilder) {
                        DeclSpace decl = (DeclSpace) builder_to_declspace [t];
                        cache = decl.MemberCache;

                        //
                        // If this DeclSpace has a MemberCache, use it.
                        //

                        if (cache != null) {
                                used_cache = true;
                                return cache.FindMembers (
                                        mt, bf, name, FilterWithClosure_delegate, null);
                        }

                        // If there is no MemberCache, we need to use the "normal" FindMembers.
                        // Note, this is a VERY uncommon route!
                        
                        MemberList list;
                        Timer.StartTimer (TimerType.FindMembers);
                        list = decl.FindMembers (mt, bf | BindingFlags.DeclaredOnly,
                                                 FilterWithClosure_delegate, name);
                        Timer.StopTimer (TimerType.FindMembers);
                        used_cache = false;
                        
                        return (MemberInfo []) list;
                }

                //
                // This call will always succeed.  There is exactly one TypeHandle instance per
                // type, TypeHandle.GetMemberCache() will, if necessary, create a new one, and return
                // the corresponding MemberCache.
                //
                cache = TypeHandle.GetMemberCache (t);

                used_cache = true;
                return cache.FindMembers (mt, bf, name, FilterWithClosure_delegate, null);
        }

        public static bool IsBuiltinType (Type t)
        {
                if (t == object_type || t == string_type || t == int32_type || t == uint32_type ||
                    t == int64_type || t == uint64_type || t == float_type || t == double_type ||
                    t == char_type || t == short_type || t == decimal_type || t == bool_type ||
                    t == sbyte_type || t == byte_type || t == ushort_type || t == void_type)
                        return true;
                else
                        return false;
        }

        public static bool IsBuiltinType (TypeContainer tc)
        {
                return IsBuiltinType (tc.TypeBuilder);
        }

        //
        // This is like IsBuiltinType, but lacks decimal_type, we should also clean up
        // the pieces in the code where we use IsBuiltinType and special case decimal_type.
        // 
        public static bool IsPrimitiveType (Type t)
        {
                return (t == int32_type || t == uint32_type ||
                    t == int64_type || t == uint64_type || t == float_type || t == double_type ||
                    t == char_type || t == short_type || t == bool_type ||
                    t == sbyte_type || t == byte_type || t == ushort_type);
        }

        public static bool IsDelegateType (Type t)
        {
                if (t.IsSubclassOf (TypeManager.delegate_type))
                        return true;
                else
                        return false;
        }
        
        public static bool IsEnumType (Type t)
        {
                if (builder_to_declspace [t] is Enum)
                        return true;

                return t.IsEnum;
        }

        public static bool IsBuiltinOrEnum (Type t)
        {
                if (IsBuiltinType (t))
                        return true;
                
                if (IsEnumType (t))
                        return true;

                return false;
        }

        static Stack unmanaged_enclosing_types = new Stack (4);

        //
        // Whether a type is unmanaged.  This is used by the unsafe code (25.2)
        //
        public static bool IsUnmanagedType (Type t)
        {
                // Avoid infloops in the case of: unsafe struct Foo { Foo *x; }
                if (unmanaged_enclosing_types.Contains (t))
                        return true;

                // builtins that are not unmanaged types
                if (t == TypeManager.object_type || t == TypeManager.string_type)
                        return false;

                if (IsBuiltinOrEnum (t))
                        return true;

                // Someone did the work of checking if the ElementType of t is unmanaged.  Let's not repeat it.
                if (t.IsPointer)
                        return true;

                // Arrays are disallowed, even if we mark them with [MarshalAs(UnmanagedType.ByValArray, ...)]
                if (t.IsArray)
                        return false;

                if (!IsValueType (t))
                        return false;

                unmanaged_enclosing_types.Push (t);

                bool retval = true;

                if (t is TypeBuilder){
                        TypeContainer tc = LookupTypeContainer (t);
                        if (tc.Fields != null){
                                foreach (FieldMember f in tc.Fields){
                                        // Avoid using f.FieldBuilder: f.Define () may not yet have been invoked.
                                        if ((f.ModFlags & Modifiers.STATIC) != 0)
                                                continue;
                                        if (f.MemberType == null)
                                                continue;
                                        if (!IsUnmanagedType (f.MemberType)){
                                                Report.SymbolRelatedToPreviousError (f.Location, CSharpName (t) + "." + f.Name);
                                                retval = false;
                                        }
                                }
                        }
                } else {
                        FieldInfo [] fields = t.GetFields (BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
                        
                        foreach (FieldInfo f in fields){
                                if (!IsUnmanagedType (f.FieldType)){
                                        Report.SymbolRelatedToPreviousError (f);
                                        retval = false;
                                }
                        }
                }

                unmanaged_enclosing_types.Pop ();

                return retval;
        }
                
        public static bool IsValueType (Type t)
        {
                if (t.IsSubclassOf (TypeManager.value_type) && (t != TypeManager.enum_type))
                        return true;
                else
                        return false;
        }
        
        public static bool IsInterfaceType (Type t)
        {
                TypeContainer tc = (TypeContainer) builder_to_declspace [t];
                if (tc == null)
                        return false;

                return tc.Kind == Kind.Interface;
        }

        public static bool IsSubclassOf (Type type, Type base_type)
        {
                do {
                        if (type.Equals (base_type))
                                return true;

                        type = type.BaseType;
                } while (type != null);

                return false;
        }

        public static bool IsFamilyAccessible (Type type, Type base_type)
        {
                return IsSubclassOf (type, base_type);
        }

        //
        // Checks whether `type' is a subclass or nested child of `base_type'.
        //
        public static bool IsNestedFamilyAccessible (Type type, Type base_type)
        {
                do {
                        if ((type == base_type) || type.IsSubclassOf (base_type))
                                return true;

                        // Handle nested types.
                        type = type.DeclaringType;
                } while (type != null);

                return false;
        }

        //
        // Checks whether `type' is a nested child of `parent'.
        //
        public static bool IsNestedChildOf (Type type, Type parent)
        {
                if (type == parent)
                        return false;

                type = type.DeclaringType;
                while (type != null) {
                        if (type == parent)
                                return true;

                        type = type.DeclaringType;
                }

                return false;
        }

        //
        // Do the right thing when returning the element type of an
        // array type based on whether we are compiling corlib or not
        //
        public static Type GetElementType (Type t)
        {
                if (RootContext.StdLib)
                        return t.GetElementType ();
                else
                        return TypeToCoreType (t.GetElementType ());
        }

        /// <summary>
        /// This method is not implemented by MS runtime for dynamic types
        /// </summary>
        public static bool HasElementType (Type t)
        {
                return t.IsArray || t.IsPointer || t.IsByRef;
        }
        
        /// <summary>
        ///   Gigantic work around for missing features in System.Reflection.Emit follows.
        /// </summary>
        ///
        /// <remarks>
        ///   Since System.Reflection.Emit can not return MethodBase.GetParameters
        ///   for anything which is dynamic, and we need this in a number of places,
        ///   we register this information here, and use it afterwards.
        /// </remarks>
        static public void RegisterMethod (MethodBase mb, Parameters ip)
        {
                method_params.Add (mb, ip);
        }
        
        static public ParameterData GetParameterData (MethodBase mb)
        {
                ParameterData pd = (ParameterData)method_params [mb];
                if (pd == null) {
                        if (mb is MethodBuilder || mb is ConstructorBuilder)
                                throw new InternalErrorException ("Argument for Method not registered" + mb);

                        pd = new ReflectionParameters (mb);
                        method_params.Add (mb, pd);
                }
                return pd;
        }

        static public void RegisterOverride (MethodBase override_method, MethodBase base_method)
        {
                if (method_overrides.Contains (override_method)) {
                        if (method_overrides [override_method] != base_method)
                                throw new InternalErrorException ("Override mismatch: " + override_method);
                        return;
                }
                method_overrides [override_method] = base_method;
        }

        static public bool IsOverride (MethodBase m)
        {
                return m.IsVirtual &&
                        (m.Attributes & MethodAttributes.NewSlot) == 0 &&
                        (m is MethodBuilder || method_overrides.Contains (m));
        }

        /// <summary>
        ///    Returns the argument types for an indexer based on its PropertyInfo
        ///
        ///    For dynamic indexers, we use the compiler provided types, for
        ///    indexers from existing assemblies we load them from GetParameters,
        ///    and insert them into the cache
        /// </summary>
        static public Type [] GetArgumentTypes (PropertyInfo indexer)
        {
                if (indexer_arguments.Contains (indexer))
                        return (Type []) indexer_arguments [indexer];
                else if (indexer is PropertyBuilder)
                        // If we're a PropertyBuilder and not in the
                        // `indexer_arguments' hash, then we're a property and
                        // not an indexer.
                        return NoTypes;
                else {
                        ParameterInfo [] pi = indexer.GetIndexParameters ();
                        // Property, not an indexer.
                        if (pi == null)
                                return NoTypes;
                        int c = pi.Length;
                        Type [] types = new Type [c];
                        
                        for (int i = 0; i < c; i++)
                                types [i] = pi [i].ParameterType;

                        indexer_arguments.Add (indexer, types);
                        return types;
                }
        }
        
        public static void RegisterConstant (FieldInfo fb, IConstant ic)
        {
                fields.Add (fb, ic);
        }

        public static IConstant GetConstant (FieldInfo fb)
        {
                if (fb == null)
                        return null;

                return (IConstant)fields [fb];
        }

        static public bool RegisterFieldBase (FieldBuilder fb, FieldBase f)
        {
                if (fieldbuilders_to_fields.Contains (fb))
                        return false;

                fieldbuilders_to_fields.Add (fb, f);
                return true;
        }

        //
        // The return value can be null;  This will be the case for
        // auxiliary FieldBuilders created by the compiler that have no
        // real field being declared on the source code
        //
        static public FieldBase GetField (FieldInfo fb)
        {
                return (FieldBase) fieldbuilders_to_fields [fb];
        }
        
        static Hashtable events;

        static public void RegisterEvent (MyEventBuilder eb, MethodBase add, MethodBase remove)
        {
                if (events == null)
                        events = new Hashtable ();

                if (!events.Contains (eb)) {
                        events.Add (eb, new Pair (add, remove));
                }
        }

        static public MethodInfo GetAddMethod (EventInfo ei)
        {
                if (ei is MyEventBuilder) {
                        Pair pair = (Pair) events [ei];

                        return (MethodInfo) pair.First;
                }
                return ei.GetAddMethod (true);
        }

        static public MethodInfo GetRemoveMethod (EventInfo ei)
        {
                if (ei is MyEventBuilder) {
                        Pair pair = (Pair) events [ei];

                        return (MethodInfo) pair.Second;
                }
                return ei.GetRemoveMethod (true);
        }

        static Hashtable priv_fields_events;

        static public bool RegisterPrivateFieldOfEvent (EventInfo einfo, FieldBuilder builder)
        {
                if (priv_fields_events == null)
                        priv_fields_events = new Hashtable ();

                if (priv_fields_events.Contains (einfo))
                        return false;

                priv_fields_events.Add (einfo, builder);

                return true;
        }

        static public MemberInfo GetPrivateFieldOfEvent (EventInfo ei)
        {
                if (priv_fields_events == null)
                        return null;
                else
                        return (MemberInfo) priv_fields_events [ei];
        }
                
        static public bool RegisterIndexer (PropertyBuilder pb, MethodBase get,
                                            MethodBase set, Type[] args)
        {
                indexer_arguments.Add (pb, args);

                return true;
        }

        public static bool CheckStructCycles (TypeContainer tc, Hashtable seen)
        {
                Hashtable hash = new Hashtable ();
                return CheckStructCycles (tc, seen, hash);
        }

        public static bool CheckStructCycles (TypeContainer tc, Hashtable seen,
                                              Hashtable hash)
        {
                if ((tc.Kind != Kind.Struct) || IsBuiltinType (tc))
                        return true;

                //
                // `seen' contains all types we've already visited.
                //
                if (seen.Contains (tc))
                        return true;
                seen.Add (tc, null);

                if (tc.Fields == null)
                        return true;

                foreach (FieldMember field in tc.Fields) {
                        if (field.FieldBuilder == null || field.FieldBuilder.IsStatic)
                                continue;

                        Type ftype = field.FieldBuilder.FieldType;
                        TypeContainer ftc = LookupTypeContainer (ftype);
                        if (ftc == null)
                                continue;

                        if (hash.Contains (ftc)) {
                                Report.Error (523, tc.Location,
                                              "Struct member `{0}.{1}' of type `{2}' " +
                                              "causes a cycle in the struct layout",
                                              tc.Name, field.Name, ftc.Name);
                                return false;
                        }

                        //
                        // `hash' contains all types in the current path.
                        //
                        hash.Add (tc, null);

                        bool ok = CheckStructCycles (ftc, seen, hash);

                        hash.Remove (tc);

                        if (!ok)
                                return false;

                        if (!seen.Contains (ftc))
                                seen.Add (ftc, null);
                }

                return true;
        }

        /// <summary>
        ///   Given an array of interface types, expand and eliminate repeated ocurrences
        ///   of an interface.  
        /// </summary>
        ///
        /// <remarks>
        ///   This expands in context like: IA; IB : IA; IC : IA, IB; the interface "IC" to
        ///   be IA, IB, IC.
        /// </remarks>
        public static Type[] ExpandInterfaces (EmitContext ec, TypeExpr [] base_interfaces)
        {
                ArrayList new_ifaces = new ArrayList ();

                foreach (TypeExpr iface in base_interfaces){
                        Type itype = iface.ResolveType (ec);
                        if (itype == null)
                                return null;

                        if (!new_ifaces.Contains (itype))
                                new_ifaces.Add (itype);
                        
                        Type [] implementing = itype.GetInterfaces ();
                        
                        foreach (Type imp in implementing){
                                if (!new_ifaces.Contains (imp))
                                        new_ifaces.Add (imp);
                        }
                }
                Type [] ret = new Type [new_ifaces.Count];
                new_ifaces.CopyTo (ret, 0);
                return ret;
        }
        
        static PtrHashtable iface_cache = new PtrHashtable ();
                
        /// <summary>
        ///   This function returns the interfaces in the type `t'.  Works with
        ///   both types and TypeBuilders.
        /// </summary>
        public static Type [] GetInterfaces (Type t)
        {
                
                Type [] cached = iface_cache [t] as Type [];
                if (cached != null)
                        return cached;
                
                //
                // The reason for catching the Array case is that Reflection.Emit
                // will not return a TypeBuilder for Array types of TypeBuilder types,
                // but will still throw an exception if we try to call GetInterfaces
                // on the type.
                //
                // Since the array interfaces are always constant, we return those for
                // the System.Array
                //
                
                if (t.IsArray)
                        t = TypeManager.array_type;
                
                if (t is TypeBuilder){
                        Type [] base_ifaces;
                        
                        if (t.BaseType == null)
                                base_ifaces = NoTypes;
                        else
                                base_ifaces = GetInterfaces (t.BaseType);
                        Type [] type_ifaces = (Type []) builder_to_ifaces [t];
                        if (type_ifaces == null)
                                type_ifaces = NoTypes;

                        int base_count = base_ifaces.Length;
                        Type [] result = new Type [base_count + type_ifaces.Length];
                        base_ifaces.CopyTo (result, 0);
                        type_ifaces.CopyTo (result, base_count);

                        iface_cache [t] = result;
                        return result;
                } else {
                        Type[] ifaces = t.GetInterfaces ();
                        iface_cache [t] = ifaces;
                        return ifaces;
                }
        }
        
        //
        // gets the interfaces that are declared explicitly on t
        //
        public static Type [] GetExplicitInterfaces (TypeBuilder t)
        {
                return (Type []) builder_to_ifaces [t];
        }
        
        /// <remarks>
        ///  The following is used to check if a given type implements an interface.
        ///  The cache helps us reduce the expense of hitting Type.GetInterfaces everytime.
        /// </remarks>
        public static bool ImplementsInterface (Type t, Type iface)
        {
                Type [] interfaces;

                //
                // FIXME OPTIMIZATION:
                // as soon as we hit a non-TypeBuiler in the interface
                // chain, we could return, as the `Type.GetInterfaces'
                // will return all the interfaces implement by the type
                // or its bases.
                //
                do {
                        interfaces = GetInterfaces (t);

                        if (interfaces != null){
                                foreach (Type i in interfaces){
                                        if (i == iface)
                                                return true;
                                }
                        }
                        
                        t = t.BaseType;
                } while (t != null);
                
                return false;
        }

        static NumberFormatInfo nf_provider = CultureInfo.CurrentCulture.NumberFormat;

        // This is a custom version of Convert.ChangeType() which works
        // with the TypeBuilder defined types when compiling corlib.
        public static object ChangeType (object value, Type conversionType, out bool error)
        {
                IConvertible convert_value = value as IConvertible;
                
                if (convert_value == null){
                        error = true;
                        return null;
                }
                
                //
                // We must use Type.Equals() here since `conversionType' is
                // the TypeBuilder created version of a system type and not
                // the system type itself.  You cannot use Type.GetTypeCode()
                // on such a type - it'd always return TypeCode.Object.
                //
                error = false;
                try {
                        if (conversionType.Equals (typeof (Boolean)))
                                return (object)(convert_value.ToBoolean (nf_provider));
                        else if (conversionType.Equals (typeof (Byte)))
                                return (object)(convert_value.ToByte (nf_provider));
                        else if (conversionType.Equals (typeof (Char)))
                                return (object)(convert_value.ToChar (nf_provider));
                        else if (conversionType.Equals (typeof (DateTime)))
                                return (object)(convert_value.ToDateTime (nf_provider));
                        else if (conversionType.Equals (TypeManager.decimal_type)) // typeof (Decimal)))
                                return (object)(convert_value.ToDecimal (nf_provider));
                        else if (conversionType.Equals (typeof (Double)))
                                return (object)(convert_value.ToDouble (nf_provider));
                        else if (conversionType.Equals (typeof (Int16)))
                                return (object)(convert_value.ToInt16 (nf_provider));
                        else if (conversionType.Equals (typeof (Int32)))
                                return (object)(convert_value.ToInt32 (nf_provider));
                        else if (conversionType.Equals (typeof (Int64)))
                                return (object)(convert_value.ToInt64 (nf_provider));
                        else if (conversionType.Equals (typeof (SByte)))
                                return (object)(convert_value.ToSByte (nf_provider));
                        else if (conversionType.Equals (typeof (Single)))
                                return (object)(convert_value.ToSingle (nf_provider));
                        else if (conversionType.Equals (typeof (String)))
                                return (object)(convert_value.ToString (nf_provider));
                        else if (conversionType.Equals (typeof (UInt16)))
                                return (object)(convert_value.ToUInt16 (nf_provider));
                        else if (conversionType.Equals (typeof (UInt32)))
                                return (object)(convert_value.ToUInt32 (nf_provider));
                        else if (conversionType.Equals (typeof (UInt64)))
                                return (object)(convert_value.ToUInt64 (nf_provider));
                        else if (conversionType.Equals (typeof (Object)))
                                return (object)(value);
                        else 
                                error = true;
                } catch {
                        error = true;
                }
                return null;
        }

        //
        // This is needed, because enumerations from assemblies
        // do not report their underlyingtype, but they report
        // themselves
        //
        public static Type EnumToUnderlying (Type t)
        {
                if (t == TypeManager.enum_type)
                        return t;

                t = t.UnderlyingSystemType;
                if (!TypeManager.IsEnumType (t))
                        return t;
        
                if (t is TypeBuilder) {
                        // slow path needed to compile corlib
                        if (t == TypeManager.bool_type ||
                            t == TypeManager.byte_type ||
                            t == TypeManager.sbyte_type ||
                            t == TypeManager.char_type ||
                            t == TypeManager.short_type ||
                            t == TypeManager.ushort_type ||
                            t == TypeManager.int32_type ||
                            t == TypeManager.uint32_type ||
                            t == TypeManager.int64_type ||
                            t == TypeManager.uint64_type)
                                return t;
                }
                TypeCode tc = Type.GetTypeCode (t);

                switch (tc){
                case TypeCode.Boolean:
                        return TypeManager.bool_type;
                case TypeCode.Byte:
                        return TypeManager.byte_type;
                case TypeCode.SByte:
                        return TypeManager.sbyte_type;
                case TypeCode.Char:
                        return TypeManager.char_type;
                case TypeCode.Int16:
                        return TypeManager.short_type;
                case TypeCode.UInt16:
                        return TypeManager.ushort_type;
                case TypeCode.Int32:
                        return TypeManager.int32_type;
                case TypeCode.UInt32:
                        return TypeManager.uint32_type;
                case TypeCode.Int64:
                        return TypeManager.int64_type;
                case TypeCode.UInt64:
                        return TypeManager.uint64_type;
                }
                throw new Exception ("Unhandled typecode in enum " + tc + " from " + t.AssemblyQualifiedName);
        }

        //
        // When compiling corlib and called with one of the core types, return
        // the corresponding typebuilder for that type.
        //
        public static Type TypeToCoreType (Type t)
        {
                if (RootContext.StdLib || (t is TypeBuilder))
                        return t;

                TypeCode tc = Type.GetTypeCode (t);

                switch (tc){
                case TypeCode.Boolean:
                        return TypeManager.bool_type;
                case TypeCode.Byte:
                        return TypeManager.byte_type;
                case TypeCode.SByte:
                        return TypeManager.sbyte_type;
                case TypeCode.Char:
                        return TypeManager.char_type;
                case TypeCode.Int16:
                        return TypeManager.short_type;
                case TypeCode.UInt16:
                        return TypeManager.ushort_type;
                case TypeCode.Int32:
                        return TypeManager.int32_type;
                case TypeCode.UInt32:
                        return TypeManager.uint32_type;
                case TypeCode.Int64:
                        return TypeManager.int64_type;
                case TypeCode.UInt64:
                        return TypeManager.uint64_type;
                case TypeCode.Single:
                        return TypeManager.float_type;
                case TypeCode.Double:
                        return TypeManager.double_type;
                case TypeCode.String:
                        return TypeManager.string_type;
                case TypeCode.Decimal:
                        return TypeManager.decimal_type;
                default:
                        if (t == typeof (void))
                                return TypeManager.void_type;
                        if (t == typeof (object))
                                return TypeManager.object_type;
                        if (t == typeof (System.Type))
                                return TypeManager.type_type;
                        if (t == typeof (System.IntPtr))
                                return TypeManager.intptr_type;
                        return t;
                }
        }

        /// <summary>
        ///   Utility function that can be used to probe whether a type
        ///   is managed or not.  
        /// </summary>
        public static bool VerifyUnManaged (Type t, Location loc)
        {
                if (IsUnmanagedType (t))
                        return true;

                Report.Error (208, loc, "Cannot take the address of, get the size of, or declare a pointer to a managed type `{0}'",
                        CSharpName (t));

                return false;   
        }
        
        /// <summary>
        ///   Returns the name of the indexer in a given type.
        /// </summary>
        /// <remarks>
        ///   The default is not always `Item'.  The user can change this behaviour by
        ///   using the IndexerNameAttribute in the container.
        ///   For example, the String class indexer is named `Chars' not `Item' 
        /// </remarks>
        public static string IndexerPropertyName (Type t)
        {
                if (t is TypeBuilder) {
                        TypeContainer tc = t.IsInterface ? LookupInterface (t) : LookupTypeContainer (t);
                        return tc == null ? TypeContainer.DefaultIndexerName : tc.IndexerName;
                }
                
                System.Attribute attr = System.Attribute.GetCustomAttribute (
                        t, TypeManager.default_member_type);
                if (attr != null){
                        DefaultMemberAttribute dma = (DefaultMemberAttribute) attr;
                        return dma.MemberName;
                }

                return TypeContainer.DefaultIndexerName;
        }

        static MethodInfo declare_local_method = null;
        
        public static LocalBuilder DeclareLocalPinned (ILGenerator ig, Type t)
        {
                if (declare_local_method == null){
                        declare_local_method = typeof (ILGenerator).GetMethod (
                                "DeclareLocal",
                                BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,
                                null, 
                                new Type [] { typeof (Type), typeof (bool)},
                                null);
                        if (declare_local_method == null){
                                Report.RuntimeMissingSupport (Location.Null, "pinned local variables");
                                return ig.DeclareLocal (t);
                        }
                }
                return (LocalBuilder) declare_local_method.Invoke (ig, new object [] { t, true });
        }
        
        //
        // Returns whether the array of memberinfos contains the given method
        //
        public static bool ArrayContainsMethod (MemberInfo [] array, MethodBase new_method)
        {
                Type [] new_args = TypeManager.GetParameterData (new_method).Types;
                
                foreach (MethodBase method in array) {
                        if (method.Name != new_method.Name)
                                continue;

                        if (method is MethodInfo && new_method is MethodInfo)
                                if (((MethodInfo) method).ReturnType != ((MethodInfo) new_method).ReturnType)
                                        continue;

                        
                        Type [] old_args = TypeManager.GetParameterData (method).Types;
                        int old_count = old_args.Length;
                        int i;
                        
                        if (new_args.Length != old_count)
                                continue;
                        
                        for (i = 0; i < old_count; i++){
                                if (old_args [i] != new_args [i])
                                        break;
                        }
                        if (i != old_count)
                                continue;

                        return true;
                }
                
                return false;
        }
        
        //
        // We copy methods from `new_members' into `target_list' if the signature
        // for the method from in the new list does not exist in the target_list
        //
        // The name is assumed to be the same.
        //
        public static ArrayList CopyNewMethods (ArrayList target_list, IList new_members)
        {
                if (target_list == null){
                        target_list = new ArrayList ();

                        foreach (MemberInfo mi in new_members){
                                if (mi is MethodBase)
                                        target_list.Add (mi);
                        }
                        return target_list;
                }
                
                MemberInfo [] target_array = new MemberInfo [target_list.Count];
                target_list.CopyTo (target_array, 0);
                
                foreach (MemberInfo mi in new_members){
                        MethodBase new_method = (MethodBase) mi;
                        
                        if (!ArrayContainsMethod (target_array, new_method))
                                target_list.Add (new_method);
                }
                return target_list;
        }


#region MemberLookup implementation
        
        //
        // Whether we allow private members in the result (since FindMembers
        // uses NonPublic for both protected and private), we need to distinguish.
        //

        static internal bool FilterNone (MemberInfo m, object filter_criteria)
        {
                return true;
        }

        internal class Closure {
                internal bool     private_ok;

                // Who is invoking us and which type is being queried currently.
                internal Type     invocation_type;
                internal Type     qualifier_type;

                // The assembly that defines the type is that is calling us
                internal Assembly invocation_assembly;
                internal IList almost_match;

                private bool CheckValidFamilyAccess (bool is_static, MemberInfo m)
                {
                        if (invocation_type == null)
                                return false;

                        if (is_static && qualifier_type == null)
                                // It resolved from a simple name, so it should be visible.
                                return true;

                        // A nested class has access to all the protected members visible to its parent.
                        if (qualifier_type != null && TypeManager.IsNestedChildOf (invocation_type, qualifier_type))
                                return true;

                        if (invocation_type == m.DeclaringType || invocation_type.IsSubclassOf (m.DeclaringType)) {
                                // Although a derived class can access protected members of its base class
                                // it cannot do so through an instance of the base class (CS1540).
                                // => Ancestry should be: declaring_type ->* invocation_type ->*  qualified_type
                                if (is_static ||
                                    qualifier_type == null ||
                                    qualifier_type == invocation_type ||
                                    qualifier_type.IsSubclassOf (invocation_type))
                                        return true;
                        }

                        if (almost_match != null)
                                almost_match.Add (m);

                        return false;
                }
                
                //
                // This filter filters by name + whether it is ok to include private
                // members in the search
                //
                internal bool Filter (MemberInfo m, object filter_criteria)
                {
                        //
                        // Hack: we know that the filter criteria will always be in the `closure'
                        // fields. 
                        //

                        if ((filter_criteria != null) && (m.Name != (string) filter_criteria))
                                return false;
                        
                        if (((qualifier_type == null) || (qualifier_type == invocation_type)) &&
                            (m.DeclaringType == invocation_type))
                                return true;
                        
                        //
                        // Ugly: we need to find out the type of `m', and depending
                        // on this, tell whether we accept or not
                        //
                        if (m is MethodBase){
                                MethodBase mb = (MethodBase) m;
                                MethodAttributes ma = mb.Attributes & MethodAttributes.MemberAccessMask;

                                if (ma == MethodAttributes.Private)
                                        return private_ok || invocation_type == m.DeclaringType ||
                                                IsNestedChildOf (invocation_type, m.DeclaringType);

                                if (invocation_assembly == mb.DeclaringType.Assembly) {
                                        if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
                                                return true;
                                } else {
                                        if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
                                                return false;
                                }

                                if (ma == MethodAttributes.Family ||
                                    ma == MethodAttributes.FamANDAssem ||
                                    ma == MethodAttributes.FamORAssem)
                                        return CheckValidFamilyAccess (mb.IsStatic, m);
                                
                                // Public.
                                return true;
                        }
                        
                        if (m is FieldInfo){
                                FieldInfo fi = (FieldInfo) m;
                                FieldAttributes fa = fi.Attributes & FieldAttributes.FieldAccessMask;
                                
                                if (fa == FieldAttributes.Private)
                                        return private_ok || (invocation_type == m.DeclaringType) ||
                                                IsNestedChildOf (invocation_type, m.DeclaringType);

                                if (invocation_assembly == fi.DeclaringType.Assembly) {
                                        if (fa == FieldAttributes.Assembly || fa == FieldAttributes.FamORAssem)
                                                return true;
                                } else {
                                        if (fa == FieldAttributes.Assembly || fa == FieldAttributes.FamANDAssem)
                                                return false;
                                }

                                if (fa == FieldAttributes.Family ||
                                    fa == FieldAttributes.FamANDAssem ||
                                    fa == FieldAttributes.FamORAssem)
                                        return CheckValidFamilyAccess (fi.IsStatic, m);
                                
                                // Public.
                                return true;
                        }
                        
                        //
                        // EventInfos and PropertyInfos, return true because they lack permission
                        // information, so we need to check later on the methods.
                        //
                        return true;
                }
        }

        static Closure closure = new Closure ();
        static MemberFilter FilterWithClosure_delegate = new MemberFilter (closure.Filter);

        //
        // Looks up a member called `name' in the `queried_type'.  This lookup
        // is done by code that is contained in the definition for `invocation_type'
        // through a qualifier of type `qualifier_type' (or null if there is no qualifier).
        //
        // `invocation_type' is used to check whether we're allowed to access the requested
        // member wrt its protection level.
        //
        // When called from MemberAccess, `qualifier_type' is the type which is used to access
        // the requested member (`class B { A a = new A (); a.foo = 5; }'; here invocation_type
        // is B and qualifier_type is A).  This is used to do the CS1540 check.
        //
        // When resolving a SimpleName, `qualifier_type' is null.
        //
        // The `qualifier_type' is used for the CS1540 check; it's normally either null or
        // the same than `queried_type' - except when we're being called from BaseAccess;
        // in this case, `invocation_type' is the current type and `queried_type' the base
        // type, so this'd normally trigger a CS1540.
        //
        // The binding flags are `bf' and the kind of members being looked up are `mt'
        //
        // The return value always includes private members which code in `invocation_type'
        // is allowed to access (using the specified `qualifier_type' if given); only use
        // BindingFlags.NonPublic to bypass the permission check.
        //
        // The 'almost_match' argument is used for reporting error CS1540.
        //
        // Returns an array of a single element for everything but Methods/Constructors
        // that might return multiple matches.
        //
        public static MemberInfo [] MemberLookup (Type invocation_type, Type qualifier_type,
                                                  Type queried_type,  MemberTypes mt,
                                                  BindingFlags original_bf, string name, IList almost_match)
        {
                Timer.StartTimer (TimerType.MemberLookup);

                MemberInfo[] retval = RealMemberLookup (invocation_type, qualifier_type,
                                                        queried_type, mt, original_bf, name, almost_match);

                Timer.StopTimer (TimerType.MemberLookup);

                return retval;
        }

        static MemberInfo [] RealMemberLookup (Type invocation_type, Type qualifier_type,
                                               Type queried_type, MemberTypes mt,
                                               BindingFlags original_bf, string name, IList almost_match)
        {
                BindingFlags bf = original_bf;
                
                ArrayList method_list = null;
                Type current_type = queried_type;
                bool searching = (original_bf & BindingFlags.DeclaredOnly) == 0;
                bool skip_iface_check = true, used_cache = false;
                bool always_ok_flag = invocation_type != null && IsNestedChildOf (invocation_type, queried_type);

                closure.invocation_type = invocation_type;
                closure.invocation_assembly = invocation_type != null ? invocation_type.Assembly : null;
                closure.qualifier_type = qualifier_type;
                closure.almost_match = almost_match;
                
                // This is from the first time we find a method
                // in most cases, we do not actually find a method in the base class
                // so we can just ignore it, and save the arraylist allocation
                MemberInfo [] first_members_list = null;
                bool use_first_members_list = false;
                
                do {
                        MemberInfo [] list;

                        //
                        // `NonPublic' is lame, because it includes both protected and
                        // private methods, so we need to control this behavior by
                        // explicitly tracking if a private method is ok or not.
                        //
                        // The possible cases are:
                        //    public, private and protected (internal does not come into the
                        //    equation)
                        //
                        if ((invocation_type != null) &&
                            ((invocation_type == current_type) ||
                             IsNestedChildOf (invocation_type, current_type)) ||
                            always_ok_flag)
                                bf = original_bf | BindingFlags.NonPublic;
                        else
                                bf = original_bf;

                        closure.private_ok = (original_bf & BindingFlags.NonPublic) != 0;

                        Timer.StopTimer (TimerType.MemberLookup);

                        list = MemberLookup_FindMembers (current_type, mt, bf, name, out used_cache);

                        Timer.StartTimer (TimerType.MemberLookup);

                        //
                        // When queried for an interface type, the cache will automatically check all
                        // inherited members, so we don't need to do this here.  However, this only
                        // works if we already used the cache in the first iteration of this loop.
                        //
                        // If we used the cache in any further iteration, we can still terminate the
                        // loop since the cache always looks in all base classes.
                        //

                        if (used_cache)
                                searching = false;
                        else
                                skip_iface_check = false;

                        if (current_type == TypeManager.object_type)
                                searching = false;
                        else {
                                current_type = current_type.BaseType;
                                
                                //
                                // This happens with interfaces, they have a null
                                // basetype.  Look members up in the Object class.
                                //
                                if (current_type == null) {
                                        current_type = TypeManager.object_type;
                                        searching = true;
                                }
                        }
                        
                        if (list.Length == 0)
                                continue;

                        //
                        // Events and types are returned by both `static' and `instance'
                        // searches, which means that our above FindMembers will
                        // return two copies of the same.
                        //
                        if (list.Length == 1 && !(list [0] is MethodBase)){
                                return list;
                        }

                        //
                        // Multiple properties: we query those just to find out the indexer
                        // name
                        //
                        if (list [0] is PropertyInfo)
                                return list;

                        //
                        // We found an event: the cache lookup returns both the event and
                        // its private field.
                        //
                        if (list [0] is EventInfo) {
                                if ((list.Length == 2) && (list [1] is FieldInfo))
                                        return new MemberInfo [] { list [0] };

                                // Oooops
                                return null;
                        }

                        //
                        // We found methods, turn the search into "method scan"
                        // mode.
                        //

                        if (first_members_list != null) {
                                if (use_first_members_list) {
                                        method_list = CopyNewMethods (method_list, first_members_list);
                                        use_first_members_list = false;
                                }
                                
                                method_list = CopyNewMethods (method_list, list);
                        } else {
                                first_members_list = list;
                                use_first_members_list = true;
                                mt &= (MemberTypes.Method | MemberTypes.Constructor);
                        }
                } while (searching);
                
                if (use_first_members_list) {
                        foreach (MemberInfo mi in first_members_list) {
                                if (! (mi is MethodBase)) {
                                        method_list = CopyNewMethods (method_list, first_members_list);
                                        return (MemberInfo []) method_list.ToArray (typeof (MemberInfo));
                                }
                        }
                        return (MemberInfo []) first_members_list;
                }

                if (method_list != null && method_list.Count > 0)
                        return (MemberInfo []) method_list.ToArray (typeof (MemberInfo));
                
                //
                // This happens if we already used the cache in the first iteration, in this case
                // the cache already looked in all interfaces.
                //
                if (skip_iface_check)
                        return null;

                //
                // Interfaces do not list members they inherit, so we have to
                // scan those.
                // 
                if (!queried_type.IsInterface)
                        return null;

                if (queried_type.IsArray)
                        queried_type = TypeManager.array_type;
                
                Type [] ifaces = GetInterfaces (queried_type);
                if (ifaces == null)
                        return null;
                
                foreach (Type itype in ifaces){
                        MemberInfo [] x;

                        x = MemberLookup (null, null, itype, mt, bf, name, null);
                        if (x != null)
                                return x;
                }
                                        
                return null;
        }

        // Tests whether external method is really special
        public static bool IsSpecialMethod (MethodBase mb)
        {
                string name = mb.Name;
                if (name.StartsWith ("get_") || name.StartsWith ("set_"))
                        return mb.DeclaringType.GetProperty (name.Substring (4)) != null;

                if (name.StartsWith ("add_"))
                        return mb.DeclaringType.GetEvent (name.Substring (4)) != null;

                if (name.StartsWith ("remove_"))
                        return mb.DeclaringType.GetEvent (name.Substring (7)) != null;

                if (name.StartsWith ("op_")){
                        foreach (string oname in Unary.oper_names) {
                                if (oname == name)
                                        return true;
                        }
                
                        foreach (string oname in Binary.oper_names) {
                                if (oname == name)
                                        return true;
                        }
                }
                return false;
        }
                
#endregion
        
}

/// <summary>
///   There is exactly one instance of this class per type.
/// </summary>
public sealed class TypeHandle : IMemberContainer {
        public readonly IMemberContainer BaseType;

        readonly int id = ++next_id;
        static int next_id = 0;

        static TypeHandle ()
        {
                Reset ();
        }

        /// <summary>
        ///   Lookup a TypeHandle instance for the given type.  If the type doesn't have
        ///   a TypeHandle yet, a new instance of it is created.  This static method
        ///   ensures that we'll only have one TypeHandle instance per type.
        /// </summary>
        private static TypeHandle GetTypeHandle (Type t)
        {
                TypeHandle handle = (TypeHandle) type_hash [t];
                if (handle != null)
                        return handle;

                handle = new TypeHandle (t);
                type_hash.Add (t, handle);
                return handle;
        }

        public static MemberCache GetMemberCache (Type t)
        {
                return GetTypeHandle (t).MemberCache;
        }
        
        public static void CleanUp ()
        {
                type_hash = null;
        }

        public static void Reset ()
        {
                type_hash = new PtrHashtable ();
        }

        /// <summary>
        ///   Returns the TypeHandle for TypeManager.object_type.
        /// </summary>
        public static IMemberContainer ObjectType {
                get {
                        if (object_type != null)
                                return object_type;

                        object_type = GetTypeHandle (TypeManager.object_type);

                        return object_type;
                }
        }

        /// <summary>
        ///   Returns the TypeHandle for TypeManager.array_type.
        /// </summary>
        public static IMemberContainer ArrayType {
                get {
                        if (array_type != null)
                                return array_type;

                        array_type = GetTypeHandle (TypeManager.array_type);

                        return array_type;
                }
        }

        private static PtrHashtable type_hash;

        private static TypeHandle object_type = null;
        private static TypeHandle array_type = null;

        private Type type;
        private bool is_interface;
        private MemberCache member_cache;
        private MemberCache base_cache;

        private TypeHandle (Type type)
        {
                this.type = type;
                if (type.BaseType != null) {
                        base_cache = TypeManager.LookupMemberCache (type.BaseType);
                        BaseType = base_cache.Container;
                } else if (type.IsInterface)
                        base_cache = TypeManager.LookupBaseInterfacesCache (type);
                this.is_interface = type.IsInterface;
                this.member_cache = new MemberCache (this);
        }

        // IMemberContainer methods

        public string Name {
                get {
                        return type.FullName;
                }
        }

        public Type Type {
                get {
                        return type;
                }
        }

        public MemberCache BaseCache {
                get {
                        return base_cache;
                }
        }

        public bool IsInterface {
                get {
                        return is_interface;
                }
        }

        public MemberList GetMembers (MemberTypes mt, BindingFlags bf)
        {
                MemberInfo [] members;
                if (mt == MemberTypes.Event)
                        members = type.GetEvents (bf | BindingFlags.DeclaredOnly);
                else
                        members = type.FindMembers (mt, bf | BindingFlags.DeclaredOnly,
                                                    null, null);
                Array.Reverse (members);

                return new MemberList (members);
        }

        // IMemberFinder methods

        public MemberList FindMembers (MemberTypes mt, BindingFlags bf, string name,
                                       MemberFilter filter, object criteria)
        {
                return new MemberList (member_cache.FindMembers (mt, bf, name, filter, criteria));
        }

        public MemberCache MemberCache {
                get {
                        return member_cache;
                }
        }

        public override string ToString ()
        {
                if (BaseType != null)
                        return "TypeHandle (" + id + "," + Name + " : " + BaseType + ")";
                else
                        return "TypeHandle (" + id + "," + Name + ")";
        }
}

}