2009-02-20 Zoltan Varga <vargaz@gmail.com>

[mcs.git] / mcs / codegen.cs

//
// codegen.cs: The code generator
//
// Author:
//   Miguel de Icaza (miguel@ximian.com)
//
// Copyright 2001, 2002, 2003 Ximian, Inc.
// Copyright 2004 Novell, Inc.
//

//
// Please leave this defined on SVN: The idea is that when we ship the
// compiler to end users, if the compiler crashes, they have a chance
// to narrow down the problem.   
//
// Only remove it if you need to debug locally on your tree.
//
#define PRODUCTION

using System;
using System.IO;
using System.Collections;
using System.Collections.Specialized;
using System.Globalization;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Cryptography;
using System.Security.Permissions;

using Mono.Security.Cryptography;

namespace Mono.CSharp {

        /// <summary>
        ///    Code generator class.
        /// </summary>
        public class CodeGen {
                static AppDomain current_domain;

                public static AssemblyClass Assembly;
                public static ModuleClass Module;

                static CodeGen ()
                {
                        Reset ();
                }

                public static void Reset ()
                {
                        Assembly = new AssemblyClass ();
                        Module = new ModuleClass (RootContext.Unsafe);
                }

                public static string Basename (string name)
                {
                        int pos = name.LastIndexOf ('/');

                        if (pos != -1)
                                return name.Substring (pos + 1);

                        pos = name.LastIndexOf ('\\');
                        if (pos != -1)
                                return name.Substring (pos + 1);

                        return name;
                }

                public static string Dirname (string name)
                {
                        int pos = name.LastIndexOf ('/');

                        if (pos != -1)
                                return name.Substring (0, pos);

                        pos = name.LastIndexOf ('\\');
                        if (pos != -1)
                                return name.Substring (0, pos);

                        return ".";
                }

                static public string FileName;

#if MS_COMPATIBLE
                const AssemblyBuilderAccess COMPILER_ACCESS = 0;
#else
                /* Keep this in sync with System.Reflection.Emit.AssemblyBuilder */
                const AssemblyBuilderAccess COMPILER_ACCESS = (AssemblyBuilderAccess) 0x800;
#endif
                                
                //
                // Initializes the code generator variables for interactive use (repl)
                //
                static public void InitDynamic (string name)
                {
                        current_domain = AppDomain.CurrentDomain;
                        AssemblyName an = Assembly.GetAssemblyName (name, name);
                        
                        Assembly.Builder = current_domain.DefineDynamicAssembly (an, AssemblyBuilderAccess.Run | COMPILER_ACCESS);
                        Module.Builder = Assembly.Builder.DefineDynamicModule (Basename (name), false);
#if GMCS_SOURCE
                        Assembly.Name = Assembly.Builder.GetName ();
#endif
                }
                
                //
                // Initializes the code generator variables
                //
                static public bool Init (string name, string output, bool want_debugging_support)
                {
                        FileName = output;
                        AssemblyName an = Assembly.GetAssemblyName (name, output);
                        if (an == null)
                                return false;

                        if (an.KeyPair != null) {
                                // If we are going to strong name our assembly make
                                // sure all its refs are strong named
                                foreach (Assembly a in RootNamespace.Global.Assemblies) {
                                        AssemblyName ref_name = a.GetName ();
                                        byte [] b = ref_name.GetPublicKeyToken ();
                                        if (b == null || b.Length == 0) {
                                                Report.Error (1577, "Assembly generation failed " +
                                                                "-- Referenced assembly '" +
                                                                ref_name.Name +
                                                                "' does not have a strong name.");
                                                //Environment.Exit (1);
                                        }
                                }
                        }
                        
                        current_domain = AppDomain.CurrentDomain;

                        try {
                                Assembly.Builder = current_domain.DefineDynamicAssembly (an,
                                        AssemblyBuilderAccess.RunAndSave | COMPILER_ACCESS, Dirname (name));
                        }
                        catch (ArgumentException) {
                                // specified key may not be exportable outside it's container
                                if (RootContext.StrongNameKeyContainer != null) {
                                        Report.Error (1548, "Could not access the key inside the container `" +
                                                RootContext.StrongNameKeyContainer + "'.");
                                        Environment.Exit (1);
                                }
                                throw;
                        }
                        catch (CryptographicException) {
                                if ((RootContext.StrongNameKeyContainer != null) || (RootContext.StrongNameKeyFile != null)) {
                                        Report.Error (1548, "Could not use the specified key to strongname the assembly.");
                                        Environment.Exit (1);
                                }
                                return false;
                        }

#if GMCS_SOURCE
                        // Get the complete AssemblyName from the builder
                        // (We need to get the public key and token)
                        Assembly.Name = Assembly.Builder.GetName ();
#endif

                        //
                        // Pass a path-less name to DefineDynamicModule.  Wonder how
                        // this copes with output in different directories then.
                        // FIXME: figure out how this copes with --output /tmp/blah
                        //
                        // If the third argument is true, the ModuleBuilder will dynamically
                        // load the default symbol writer.
                        //
                        try {
                                Module.Builder = Assembly.Builder.DefineDynamicModule (
                                        Basename (name), Basename (output), want_debugging_support);

#if !MS_COMPATIBLE
                                // TODO: We should use SymbolWriter from DefineDynamicModule
                                if (want_debugging_support && !SymbolWriter.Initialize (Module.Builder, output)) {
                                        Report.Error (40, "Unexpected debug information initialization error `{0}'",
                                                "Could not find the symbol writer assembly (Mono.CompilerServices.SymbolWriter.dll)");
                                        return false;
                                }
#endif
                        } catch (ExecutionEngineException e) {
                                Report.Error (40, "Unexpected debug information initialization error `{0}'",
                                        e.Message);
                                return false;
                        }

                        return true;
                }

                static public void Save (string name, bool saveDebugInfo)
                {
                        try {
                                Assembly.Builder.Save (Basename (name));
                        }
                        catch (COMException) {
                                if ((RootContext.StrongNameKeyFile == null) || (!RootContext.StrongNameDelaySign))
                                        throw;

                                // FIXME: it seems Microsoft AssemblyBuilder doesn't like to delay sign assemblies 
                                Report.Error (1548, "Couldn't delay-sign the assembly with the '" +
                                        RootContext.StrongNameKeyFile +
                                        "', Use MCS with the Mono runtime or CSC to compile this assembly.");
                        }
                        catch (System.IO.IOException io) {
                                Report.Error (16, "Could not write to file `"+name+"', cause: " + io.Message);
                                return;
                        }
                        catch (System.UnauthorizedAccessException ua) {
                                Report.Error (16, "Could not write to file `"+name+"', cause: " + ua.Message);
                                return;
                        }

                        //
                        // Write debuger symbol file
                        //
                        if (saveDebugInfo)
                                SymbolWriter.WriteSymbolFile ();
                        }
        }


        /// <summary>
        /// An interface to hold all the information needed in the resolving phase.
        /// </summary>
        public interface IResolveContext
        {
                DeclSpace DeclContainer { get; }
                bool IsInObsoleteScope { get; }
                bool IsInUnsafeScope { get; }

                // the declcontainer to lookup for type-parameters.  Should only use LookupGeneric on it.
                //
                // FIXME: This is somewhat of a hack.  We don't need a full DeclSpace for this.  We just need the
                //        current type parameters in scope. IUIC, that will require us to rewrite GenericMethod.
                //        Maybe we can replace this with a 'LookupGeneric (string)' instead, but we'll have to 
                //        handle generic method overrides differently
                DeclSpace GenericDeclContainer { get; }
        }

        /// <summary>
        ///   An Emit Context is created for each body of code (from methods,
        ///   properties bodies, indexer bodies or constructor bodies)
        /// </summary>
        public class EmitContext : IResolveContext {

                //
                // Holds a varible used during collection or object initialization.
                //
                public Expression CurrentInitializerVariable;

                DeclSpace decl_space;
                
                public DeclSpace TypeContainer;
                public ILGenerator ig;

                [Flags]
                public enum Flags : int {
                        /// <summary>
                        ///   This flag tracks the `checked' state of the compilation,
                        ///   it controls whether we should generate code that does overflow
                        ///   checking, or if we generate code that ignores overflows.
                        ///
                        ///   The default setting comes from the command line option to generate
                        ///   checked or unchecked code plus any source code changes using the
                        ///   checked/unchecked statements or expressions.   Contrast this with
                        ///   the ConstantCheckState flag.
                        /// </summary>
                        CheckState = 1 << 0,

                        /// <summary>
                        ///   The constant check state is always set to `true' and cant be changed
                        ///   from the command line.  The source code can change this setting with
                        ///   the `checked' and `unchecked' statements and expressions. 
                        /// </summary>
                        ConstantCheckState = 1 << 1,

                        AllCheckStateFlags = CheckState | ConstantCheckState,

                        /// <summary>
                        ///  Whether we are inside an unsafe block
                        /// </summary>
                        InUnsafe = 1 << 2,

                        InCatch = 1 << 3,
                        InFinally = 1 << 4,

                        /// <summary>
                        ///   Whether control flow analysis is enabled
                        /// </summary>
                        DoFlowAnalysis = 1 << 5,

                        /// <summary>
                        ///   Whether control flow analysis is disabled on structs
                        ///   (only meaningful when DoFlowAnalysis is set)
                        /// </summary>
                        OmitStructFlowAnalysis = 1 << 6,

                        ///
                        /// Indicates the current context is in probing mode, no errors are reported. 
                        ///
                        ProbingMode = 1 <<      7,

                        //
                        // Inside field intializer expression
                        //
                        InFieldInitializer = 1 << 8,
                        
                        InferReturnType = 1 << 9,
                        
                        InCompoundAssignment = 1 << 10,

                        OmitDebuggingInfo = 1 << 11
                }

                Flags flags;

                /// <summary>
                ///   Whether we are emitting code inside a static or instance method
                /// </summary>
                public bool IsStatic;

                /// <summary>
                ///   Whether the actual created method is static or instance method.
                ///   Althoug the method might be declared as `static', if an anonymous
                ///   method is involved, we might turn this into an instance method.
                ///
                ///   So this reflects the low-level staticness of the method, while
                ///   IsStatic represents the semantic, high-level staticness.
                /// </summary>
                //public bool MethodIsStatic;

                /// <summary>
                ///   The value that is allowed to be returned or NULL if there is no
                ///   return type.
                /// </summary>
                Type return_type;

                /// <summary>
                ///   Points to the Type (extracted from the TypeContainer) that
                ///   declares this body of code
                /// </summary>
                public readonly Type ContainerType;
                
                /// <summary>
                ///   Whether this is generating code for a constructor
                /// </summary>
                public bool IsConstructor;

                /// <summary>
                ///   Keeps track of the Type to LocalBuilder temporary storage created
                ///   to store structures (used to compute the address of the structure
                ///   value on structure method invocations)
                /// </summary>
                public Hashtable temporary_storage;

                public Block CurrentBlock;

                public int CurrentFile;

                /// <summary>
                ///   The location where we store the return value.
                /// </summary>
                LocalBuilder return_value;

                /// <summary>
                ///   The location where return has to jump to return the
                ///   value
                /// </summary>
                public Label ReturnLabel;

                /// <summary>
                ///   If we already defined the ReturnLabel
                /// </summary>
                public bool HasReturnLabel;

                /// <summary>
                ///  Whether we are in a `fixed' initialization
                /// </summary>
                public bool InFixedInitializer;

                /// <summary>
                ///  Whether we are inside an anonymous method.
                /// </summary>
                public AnonymousExpression CurrentAnonymousMethod;
                
                /// <summary>
                ///   Location for this EmitContext
                /// </summary>
                public Location loc;

                /// <summary>
                ///   Inside an enum definition, we do not resolve enumeration values
                ///   to their enumerations, but rather to the underlying type/value
                ///   This is so EnumVal + EnumValB can be evaluated.
                ///
                ///   There is no "E operator + (E x, E y)", so during an enum evaluation
                ///   we relax the rules
                /// </summary>
                public bool InEnumContext;

                public readonly IResolveContext ResolveContext;

                /// <summary>
                ///    The current iterator
                /// </summary>
                public Iterator CurrentIterator {
                        get { return CurrentAnonymousMethod as Iterator; }
                }

                /// <summary>
                ///    Whether we are in the resolving stage or not
                /// </summary>
                enum Phase {
                        Created,
                        Resolving,
                        Emitting
                }

                bool isAnonymousMethodAllowed = true;

                Phase current_phase;
                FlowBranching current_flow_branching;

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

                public override string ToString ()
                {
                        return String.Format ("EmitContext ({0}:{1})", id,
                                              CurrentAnonymousMethod, loc);
                }
                
                public EmitContext (IResolveContext rc, DeclSpace parent, DeclSpace ds, Location l, ILGenerator ig,
                                    Type return_type, int code_flags, bool is_constructor)
                {
                        this.ResolveContext = rc;
                        this.ig = ig;

                        TypeContainer = parent;
                        this.decl_space = ds;
                        if (RootContext.Checked)
                                flags |= Flags.CheckState;
                        flags |= Flags.ConstantCheckState;

                        if (return_type == null)
                                throw new ArgumentNullException ("return_type");
#if GMCS_SOURCE
                        if ((return_type is TypeBuilder) && return_type.IsGenericTypeDefinition)
                                throw new InternalErrorException ();
#endif

                        IsStatic = (code_flags & Modifiers.STATIC) != 0;
                        ReturnType = return_type;
                        IsConstructor = is_constructor;
                        CurrentBlock = null;
                        CurrentFile = 0;
                        current_phase = Phase.Created;

                        if (parent != null){
                                // Can only be null for the ResolveType contexts.
                                ContainerType = parent.TypeBuilder;
                                if (rc.IsInUnsafeScope)
                                        flags |= Flags.InUnsafe;
                        }
                        loc = l;
                }

                public EmitContext (IResolveContext rc, DeclSpace ds, Location l, ILGenerator ig,
                                    Type return_type, int code_flags, bool is_constructor)
                        : this (rc, ds, ds, l, ig, return_type, code_flags, is_constructor)
                {
                }

                public EmitContext (IResolveContext rc, DeclSpace ds, Location l, ILGenerator ig,
                                    Type return_type, int code_flags)
                        : this (rc, ds, ds, l, ig, return_type, code_flags, false)
                {
                }

                // IResolveContext.DeclContainer
                public DeclSpace DeclContainer { 
                        get { return decl_space; }
                        set { decl_space = value; }
                }

                // IResolveContext.GenericDeclContainer
                public DeclSpace GenericDeclContainer {
                        get { return DeclContainer; }
                }

                public bool CheckState {
                        get { return (flags & Flags.CheckState) != 0; }
                }

                public bool ConstantCheckState {
                        get { return (flags & Flags.ConstantCheckState) != 0; }
                }

                public bool InUnsafe {
                        get { return (flags & Flags.InUnsafe) != 0; }
                }

                public bool InCatch {
                        get { return (flags & Flags.InCatch) != 0; }
                }

                public bool InFinally {
                        get { return (flags & Flags.InFinally) != 0; }
                }

                public bool DoFlowAnalysis {
                        get { return (flags & Flags.DoFlowAnalysis) != 0; }
                }

                public bool OmitStructFlowAnalysis {
                        get { return (flags & Flags.OmitStructFlowAnalysis) != 0; }
                }

                // utility helper for CheckExpr, UnCheckExpr, Checked and Unchecked statements
                // it's public so that we can use a struct at the callsite
                public struct FlagsHandle : IDisposable
                {
                        EmitContext ec;
                        readonly Flags invmask, oldval;

                        public FlagsHandle (EmitContext ec, Flags flagsToSet)
                                : this (ec, flagsToSet, flagsToSet)
                        {
                        }

                        internal FlagsHandle (EmitContext ec, Flags mask, Flags val)
                        {
                                this.ec = ec;
                                invmask = ~mask;
                                oldval = ec.flags & mask;
                                ec.flags = (ec.flags & invmask) | (val & mask);

                                if ((mask & Flags.ProbingMode) != 0)
                                        Report.DisableReporting ();
                        }

                        public void Dispose ()
                        {
                                if ((invmask & Flags.ProbingMode) == 0)
                                        Report.EnableReporting ();

                                ec.flags = (ec.flags & invmask) | oldval;
                        }
                }

                // Temporarily set all the given flags to the given value.  Should be used in an 'using' statement
                public FlagsHandle Set (Flags flagsToSet)
                {
                        return new FlagsHandle (this, flagsToSet);
                }

                public FlagsHandle With (Flags bits, bool enable)
                {
                        return new FlagsHandle (this, bits, enable ? bits : 0);
                }

                public FlagsHandle WithFlowAnalysis (bool do_flow_analysis, bool omit_struct_analysis)
                {
                        Flags newflags = 
                                (do_flow_analysis ? Flags.DoFlowAnalysis : 0) |
                                (omit_struct_analysis ? Flags.OmitStructFlowAnalysis : 0);
                        return new FlagsHandle (this, Flags.DoFlowAnalysis | Flags.OmitStructFlowAnalysis, newflags);
                }
                
                /// <summary>
                ///   If this is true, then Return and ContextualReturn statements
                ///   will set the ReturnType value based on the expression types
                ///   of each return statement instead of the method return type
                ///   (which is initially null).
                /// </summary>
                public bool InferReturnType {
                        get { return (flags & Flags.InferReturnType) != 0; }
                }

                // IResolveContext.IsInObsoleteScope
                public bool IsInObsoleteScope {
                        get {
                                // Disables obsolete checks when probing is on
                                return IsInProbingMode || ResolveContext.IsInObsoleteScope;
                        }
                }

                public bool IsInProbingMode {
                        get { return (flags & Flags.ProbingMode) != 0; }
                }

                // IResolveContext.IsInUnsafeScope
                public bool IsInUnsafeScope {
                        get { return InUnsafe || ResolveContext.IsInUnsafeScope; }
                }

                public bool IsAnonymousMethodAllowed {
                        get { return isAnonymousMethodAllowed; }
                        set { isAnonymousMethodAllowed = value; }
                }

                public bool IsInFieldInitializer {
                        get { return (flags & Flags.InFieldInitializer) != 0; }
                }
                
                public bool IsInCompoundAssignment {
                        get { return (flags & Flags.InCompoundAssignment) != 0; }
                }

                public bool IsVariableCapturingRequired {
                        get {
                                return !IsInProbingMode && (CurrentBranching == null || !CurrentBranching.CurrentUsageVector.IsUnreachable);
                        }
                }

                public FlowBranching CurrentBranching {
                        get { return current_flow_branching; }
                }

                public bool OmitDebuggingInfo {
                        get { return (flags & Flags.OmitDebuggingInfo) != 0; }
                        set {
                                if (value)
                                        flags |= Flags.OmitDebuggingInfo;
                                else
                                        flags &= ~Flags.OmitDebuggingInfo;
                        }
                }

                // <summary>
                //   Starts a new code branching.  This inherits the state of all local
                //   variables and parameters from the current branching.
                // </summary>
                public FlowBranching StartFlowBranching (FlowBranching.BranchingType type, Location loc)
                {
                        current_flow_branching = FlowBranching.CreateBranching (CurrentBranching, type, null, loc);
                        return current_flow_branching;
                }

                // <summary>
                //   Starts a new code branching for block `block'.
                // </summary>
                public FlowBranching StartFlowBranching (Block block)
                {
                        flags |= Flags.DoFlowAnalysis;

                        current_flow_branching = FlowBranching.CreateBranching (
                                CurrentBranching, FlowBranching.BranchingType.Block, block, block.StartLocation);
                        return current_flow_branching;
                }

                public FlowBranchingTryCatch StartFlowBranching (TryCatch stmt)
                {
                        FlowBranchingTryCatch branching = new FlowBranchingTryCatch (CurrentBranching, stmt);
                        current_flow_branching = branching;
                        return branching;
                }

                public FlowBranchingException StartFlowBranching (ExceptionStatement stmt)
                {
                        FlowBranchingException branching = new FlowBranchingException (CurrentBranching, stmt);
                        current_flow_branching = branching;
                        return branching;
                }

                public FlowBranchingLabeled StartFlowBranching (LabeledStatement stmt)
                {
                        FlowBranchingLabeled branching = new FlowBranchingLabeled (CurrentBranching, stmt);
                        current_flow_branching = branching;
                        return branching;
                }

                public FlowBranchingIterator StartFlowBranching (Iterator iterator)
                {
                        FlowBranchingIterator branching = new FlowBranchingIterator (CurrentBranching, iterator);
                        current_flow_branching = branching;
                        return branching;
                }

                public FlowBranchingToplevel StartFlowBranching (ToplevelBlock stmt)
                {
                        FlowBranchingToplevel branching = new FlowBranchingToplevel (CurrentBranching, stmt);
                        current_flow_branching = branching;
                        return branching;
                }

                // <summary>
                //   Ends a code branching.  Merges the state of locals and parameters
                //   from all the children of the ending branching.
                // </summary>
                public bool EndFlowBranching ()
                {
                        FlowBranching old = current_flow_branching;
                        current_flow_branching = current_flow_branching.Parent;

                        FlowBranching.UsageVector vector = current_flow_branching.MergeChild (old);
                        return vector.IsUnreachable;
                }

                // <summary>
                //   Kills the current code branching.  This throws away any changed state
                //   information and should only be used in case of an error.
                // </summary>
                // FIXME: this is evil
                public void KillFlowBranching ()
                {
                        current_flow_branching = current_flow_branching.Parent;
                }

                public bool MustCaptureVariable (LocalInfo local)
                {
                        if (CurrentAnonymousMethod == null)
                                return false;

                        // FIXME: IsIterator is too aggressive, we should capture only if child
                        // block contains yield
                        if (CurrentAnonymousMethod.IsIterator)
                                return true;

                        return local.Block.Toplevel != CurrentBlock.Toplevel;
                }
                
                public void EmitMeta (ToplevelBlock b)
                {
                        b.EmitMeta (this);

                        if (HasReturnLabel)
                                ReturnLabel = ig.DefineLabel ();
                }

                //
                // Here until we can fix the problem with Mono.CSharp.Switch, which
                // currently can not cope with ig == null during resolve (which must
                // be fixed for switch statements to work on anonymous methods).
                //
                public void EmitTopBlock (IMethodData md, ToplevelBlock block)
                {
                        if (block == null)
                                return;
                        
                        bool unreachable;
                        
                        if (ResolveTopBlock (null, block, md.ParameterInfo, md, out unreachable)){
                                if (Report.Errors > 0)
                                        return;

                                EmitMeta (block);

                                current_phase = Phase.Emitting;
#if PRODUCTION
                                try {
#endif
                                EmitResolvedTopBlock (block, unreachable);
#if PRODUCTION
                                } catch (Exception e){
                                        Console.WriteLine ("Exception caught by the compiler while emitting:");
                                        Console.WriteLine ("   Block that caused the problem begin at: " + block.loc);
                                        
                                        Console.WriteLine (e.GetType ().FullName + ": " + e.Message);
                                        throw;
                                }
#endif
                        }
                }

                bool resolved;
                bool unreachable;

                public bool ResolveTopBlock (EmitContext anonymous_method_host, ToplevelBlock block,
                                             ParametersCompiled ip, IMethodData md, out bool unreachable)
                {
                        if (resolved) {
                                unreachable = this.unreachable;
                                return true;
                        }

                        current_phase = Phase.Resolving;
                        unreachable = false;

                        if (!loc.IsNull)
                                CurrentFile = loc.File;

#if PRODUCTION
                        try {
#endif
                                if (!block.ResolveMeta (this, ip))
                                        return false;

                                using (this.With (EmitContext.Flags.DoFlowAnalysis, true)) {
                                        FlowBranchingToplevel top_level;
                                        if (anonymous_method_host != null)
                                                top_level = new FlowBranchingToplevel (anonymous_method_host.CurrentBranching, block);
                                        else 
                                                top_level = block.TopLevelBranching;

                                        current_flow_branching = top_level;
                                        bool ok = block.Resolve (this);
                                        current_flow_branching = null;

                                        if (!ok)
                                                return false;

                                        bool flow_unreachable = top_level.End ();
                                        if (flow_unreachable)
                                                this.unreachable = unreachable = true;
                                }
#if PRODUCTION
                        } catch (Exception e) {
                                Console.WriteLine ("Exception caught by the compiler while compiling:");
                                Console.WriteLine ("   Block that caused the problem begin at: " + loc);

                                if (CurrentBlock != null){
                                        Console.WriteLine ("                     Block being compiled: [{0},{1}]",
                                                           CurrentBlock.StartLocation, CurrentBlock.EndLocation);
                                }
                                Console.WriteLine (e.GetType ().FullName + ": " + e.Message);
                                throw;
                        }
#endif

                        if (return_type != TypeManager.void_type && !unreachable) {
                                if (CurrentAnonymousMethod == null) {
                                        Report.Error (161, md.Location, "`{0}': not all code paths return a value", md.GetSignatureForError ());
                                        return false;
                                } else if (!CurrentAnonymousMethod.IsIterator) {
                                        Report.Error (1643, CurrentAnonymousMethod.Location, "Not all code paths return a value in anonymous method of type `{0}'",
                                                      CurrentAnonymousMethod.GetSignatureForError ());
                                        return false;
                                }
                        }

                        resolved = true;
                        return true;
                }

                public Type ReturnType {
                        set {
                                return_type = value;
                        }
                        get {
                                return return_type;
                        }
                }

                public void EmitResolvedTopBlock (ToplevelBlock block, bool unreachable)
                {
                        if (block != null)
                                block.Emit (this);

                        if (HasReturnLabel)
                                ig.MarkLabel (ReturnLabel);

                        if (return_value != null){
                                ig.Emit (OpCodes.Ldloc, return_value);
                                ig.Emit (OpCodes.Ret);
                        } else {
                                //
                                // If `HasReturnLabel' is set, then we already emitted a
                                // jump to the end of the method, so we must emit a `ret'
                                // there.
                                //
                                // Unfortunately, System.Reflection.Emit automatically emits
                                // a leave to the end of a finally block.  This is a problem
                                // if no code is following the try/finally block since we may
                                // jump to a point after the end of the method.
                                // As a workaround, we're always creating a return label in
                                // this case.
                                //

                                if (HasReturnLabel || !unreachable) {
                                        if (return_type != TypeManager.void_type)
                                                ig.Emit (OpCodes.Ldloc, TemporaryReturn ());
                                        ig.Emit (OpCodes.Ret);
                                }
                        }
                }

                /// <summary>
                ///   This is called immediately before emitting an IL opcode to tell the symbol
                ///   writer to which source line this opcode belongs.
                /// </summary>
                public void Mark (Location loc)
                {
                        if (!SymbolWriter.HasSymbolWriter || OmitDebuggingInfo || loc.IsNull)
                                return;

                        SymbolWriter.MarkSequencePoint (ig, loc);
                }

                public void DefineLocalVariable (string name, LocalBuilder builder)
                {
                        SymbolWriter.DefineLocalVariable (name, builder);
                }

                public void BeginScope ()
                {
                        ig.BeginScope();
                        SymbolWriter.OpenScope(ig);
                }

                public void EndScope ()
                {
                        ig.EndScope();
                        SymbolWriter.CloseScope(ig);
                }

                /// <summary>
                ///   Returns a temporary storage for a variable of type t as 
                ///   a local variable in the current body.
                /// </summary>
                public LocalBuilder GetTemporaryLocal (Type t)
                {
                        if (temporary_storage != null) {
                                object o = temporary_storage [t];
                                if (o != null) {
                                        if (o is Stack) {
                                                Stack s = (Stack) o;
                                                o = s.Count == 0 ? null : s.Pop ();
                                        } else {
                                                temporary_storage.Remove (t);
                                        }
                                }
                                if (o != null)
                                        return (LocalBuilder) o;
                        }
                        return ig.DeclareLocal (t);
                }

                public void FreeTemporaryLocal (LocalBuilder b, Type t)
                {
                        if (temporary_storage == null) {
                                temporary_storage = new Hashtable ();
                                temporary_storage [t] = b;
                                return;
                        }
                        object o = temporary_storage [t];
                        if (o == null) {
                                temporary_storage [t] = b;
                                return;
                        }
                        Stack s = o as Stack;
                        if (s == null) {
                                s = new Stack ();
                                s.Push (o);
                                temporary_storage [t] = s;
                        }
                        s.Push (b);
                }

                /// <summary>
                ///   Current loop begin and end labels.
                /// </summary>
                public Label LoopBegin, LoopEnd;

                /// <summary>
                ///   Default target in a switch statement.   Only valid if
                ///   InSwitch is true
                /// </summary>
                public Label DefaultTarget;

                /// <summary>
                ///   If this is non-null, points to the current switch statement
                /// </summary>
                public Switch Switch;

                /// <summary>
                ///   ReturnValue creates on demand the LocalBuilder for the
                ///   return value from the function.  By default this is not
                ///   used.  This is only required when returns are found inside
                ///   Try or Catch statements.
                ///
                ///   This method is typically invoked from the Emit phase, so
                ///   we allow the creation of a return label if it was not
                ///   requested during the resolution phase.   Could be cleaned
                ///   up, but it would replicate a lot of logic in the Emit phase
                ///   of the code that uses it.
                /// </summary>
                public LocalBuilder TemporaryReturn ()
                {
                        if (return_value == null){
                                return_value = ig.DeclareLocal (return_type);
                                if (!HasReturnLabel){
                                        ReturnLabel = ig.DefineLabel ();
                                        HasReturnLabel = true;
                                }
                        }

                        return return_value;
                }

                /// <summary>
                ///   This method is used during the Resolution phase to flag the
                ///   need to define the ReturnLabel
                /// </summary>
                public void NeedReturnLabel ()
                {
                        if (current_phase != Phase.Resolving){
                                //
                                // The reason is that the `ReturnLabel' is declared between
                                // resolution and emission
                                // 
                                throw new Exception ("NeedReturnLabel called from Emit phase, should only be called during Resolve");
                        }
                        
                        if (!HasReturnLabel)
                                HasReturnLabel = true;
                }


                public Expression GetThis (Location loc)
                {
                        This my_this;
                        if (CurrentBlock != null)
                                my_this = new This (CurrentBlock, loc);
                        else
                                my_this = new This (loc);

                        if (!my_this.ResolveBase (this))
                                my_this = null;

                        return my_this;
                }
        }


        public abstract class CommonAssemblyModulClass : Attributable, IResolveContext {

                protected CommonAssemblyModulClass ():
                        base (null)
                {
                }

                public void AddAttributes (ArrayList attrs)
                {
                        foreach (Attribute a in attrs)
                                a.AttachTo (this);

                        if (attributes == null) {
                                attributes = new Attributes (attrs);
                                return;
                        }
                        attributes.AddAttributes (attrs);
                }

                public virtual void Emit (TypeContainer tc) 
                {
                        if (OptAttributes == null)
                                return;

                        OptAttributes.Emit ();
                }

                protected Attribute ResolveAttribute (Type a_type)
                {
                        Attribute a = OptAttributes.Search (a_type);
                        if (a != null) {
                                a.Resolve ();
                        }
                        return a;
                }

                public override IResolveContext ResolveContext {
                        get { return this; }
                }

                #region IResolveContext Members

                public DeclSpace DeclContainer {
                        get { return RootContext.ToplevelTypes; }
                }

                public DeclSpace GenericDeclContainer {
                        get { return DeclContainer; }
                }

                public bool IsInObsoleteScope {
                        get { return false; }
                }

                public bool IsInUnsafeScope {
                        get { return false; }
                }

                #endregion
        }
                
        public class AssemblyClass : CommonAssemblyModulClass {
                // TODO: make it private and move all builder based methods here
                public AssemblyBuilder Builder;
                bool is_cls_compliant;
                bool wrap_non_exception_throws;
                Type runtime_compatibility_attr_type;

                public Attribute ClsCompliantAttribute;

                ListDictionary declarative_security;
#if GMCS_SOURCE
                bool has_extension_method;              
                public AssemblyName Name;
                MethodInfo add_type_forwarder;
                ListDictionary emitted_forwarders;
#endif

                // Module is here just because of error messages
                static string[] attribute_targets = new string [] { "assembly", "module" };

                public AssemblyClass (): base ()
                {
#if GMCS_SOURCE
                        wrap_non_exception_throws = true;
#endif
                }

                public bool HasExtensionMethods {
                        set {
#if GMCS_SOURCE                         
                                has_extension_method = value;
#endif
                        }
                }

                public bool IsClsCompliant {
                        get {
                                return is_cls_compliant;
                        }
                }

                public bool WrapNonExceptionThrows {
                        get {
                                return wrap_non_exception_throws;
                        }
                }

                public override AttributeTargets AttributeTargets {
                        get {
                                return AttributeTargets.Assembly;
                        }
                }

                public override bool IsClsComplianceRequired ()
                {
                        return is_cls_compliant;
                }

                public void Resolve ()
                {
                        runtime_compatibility_attr_type = TypeManager.CoreLookupType (
                                "System.Runtime.CompilerServices", "RuntimeCompatibilityAttribute", Kind.Class, false);

                        if (RootContext.Unsafe) {
                                //
                                // Emits [assembly: SecurityPermissionAttribute (SecurityAction.RequestMinimum, SkipVerification = true)]
                                // when -unsafe option was specified
                                //
                                
                                Location loc = Location.Null;

                                MemberAccess system_security_permissions = new MemberAccess (new MemberAccess (
                                        new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Security", loc), "Permissions", loc);

                                ArrayList pos = new ArrayList (1);
                                pos.Add (new Argument (new MemberAccess (new MemberAccess (system_security_permissions, "SecurityAction", loc), "RequestMinimum")));

                                ArrayList named = new ArrayList (1);
                                named.Add (new DictionaryEntry ("SkipVerification", new Argument (new BoolLiteral (true, loc))));

                                GlobalAttribute g = new GlobalAttribute (new NamespaceEntry (null, null, null), "assembly", system_security_permissions,
                                        "SecurityPermissionAttribute", new object[] { pos, named }, loc, false);
                                g.AttachTo (this);

                                if (g.Resolve () != null) {
                                        declarative_security = new ListDictionary ();
                                        g.ExtractSecurityPermissionSet (declarative_security);
                                }
                        }

                        if (OptAttributes == null)
                                return;

                        // Ensure that we only have GlobalAttributes, since the Search isn't safe with other types.
                        if (!OptAttributes.CheckTargets())
                                return;

                        if (TypeManager.cls_compliant_attribute_type != null)
                                ClsCompliantAttribute = ResolveAttribute (TypeManager.cls_compliant_attribute_type);

                        if (ClsCompliantAttribute != null) {
                                is_cls_compliant = ClsCompliantAttribute.GetClsCompliantAttributeValue ();
                        }

                        if (runtime_compatibility_attr_type != null) {
                                Attribute a = ResolveAttribute (runtime_compatibility_attr_type);
                                if (a != null) {
                                        object val = a.GetPropertyValue ("WrapNonExceptionThrows");
                                        if (val != null)
                                                wrap_non_exception_throws = (bool) val;
                                }
                        }
                }

                // fix bug #56621
                private void SetPublicKey (AssemblyName an, byte[] strongNameBlob) 
                {
                        try {
                                // check for possible ECMA key
                                if (strongNameBlob.Length == 16) {
                                        // will be rejected if not "the" ECMA key
                                        an.SetPublicKey (strongNameBlob);
                                }
                                else {
                                        // take it, with or without, a private key
                                        RSA rsa = CryptoConvert.FromCapiKeyBlob (strongNameBlob);
                                        // and make sure we only feed the public part to Sys.Ref
                                        byte[] publickey = CryptoConvert.ToCapiPublicKeyBlob (rsa);
                                        
                                        // AssemblyName.SetPublicKey requires an additional header
                                        byte[] publicKeyHeader = new byte [12] { 0x00, 0x24, 0x00, 0x00, 0x04, 0x80, 0x00, 0x00, 0x94, 0x00, 0x00, 0x00 };

                                        byte[] encodedPublicKey = new byte [12 + publickey.Length];
                                        Buffer.BlockCopy (publicKeyHeader, 0, encodedPublicKey, 0, 12);
                                        Buffer.BlockCopy (publickey, 0, encodedPublicKey, 12, publickey.Length);
                                        an.SetPublicKey (encodedPublicKey);
                                }
                        }
                        catch (Exception) {
                                Error_AssemblySigning ("The specified file `" + RootContext.StrongNameKeyFile + "' is incorrectly encoded");
                                Environment.Exit (1);
                        }
                }

                // TODO: rewrite this code (to kill N bugs and make it faster) and use standard ApplyAttribute way.
                public AssemblyName GetAssemblyName (string name, string output) 
                {
                        if (OptAttributes != null) {
                                foreach (Attribute a in OptAttributes.Attrs) {
                                        // cannot rely on any resolve-based members before you call Resolve
                                        if (a.ExplicitTarget == null || a.ExplicitTarget != "assembly")
                                                continue;

                                        // TODO: This code is buggy: comparing Attribute name without resolving is wrong.
                                        //       However, this is invoked by CodeGen.Init, when none of the namespaces
                                        //       are loaded yet.
                                        // TODO: Does not handle quoted attributes properly
                                        switch (a.Name) {
                                        case "AssemblyKeyFile":
                                        case "AssemblyKeyFileAttribute":
                                        case "System.Reflection.AssemblyKeyFileAttribute":
                                                if (RootContext.StrongNameKeyFile != null) {
                                                        Report.SymbolRelatedToPreviousError (a.Location, a.Name);
                                                        Report.Warning (1616, 1, "Option `{0}' overrides attribute `{1}' given in a source file or added module",
                                                                        "keyfile", "System.Reflection.AssemblyKeyFileAttribute");
                                                } else {
                                                        string value = a.GetString ();
                                                        if (value.Length != 0)
                                                                RootContext.StrongNameKeyFile = value;
                                                }
                                                break;
                                        case "AssemblyKeyName":
                                        case "AssemblyKeyNameAttribute":
                                        case "System.Reflection.AssemblyKeyNameAttribute":
                                                if (RootContext.StrongNameKeyContainer != null) {
                                                        Report.SymbolRelatedToPreviousError (a.Location, a.Name);
                                                        Report.Warning (1616, 1, "Option `{0}' overrides attribute `{1}' given in a source file or added module",
                                                                        "keycontainer", "System.Reflection.AssemblyKeyNameAttribute");
                                                } else {
                                                        string value = a.GetString ();
                                                        if (value.Length != 0)
                                                                RootContext.StrongNameKeyContainer = value;
                                                }
                                                break;
                                        case "AssemblyDelaySign":
                                        case "AssemblyDelaySignAttribute":
                                        case "System.Reflection.AssemblyDelaySignAttribute":
                                                RootContext.StrongNameDelaySign = a.GetBoolean ();
                                                break;
                                        }
                                }
                        }
                        
                        AssemblyName an = new AssemblyName ();
                        an.Name = Path.GetFileNameWithoutExtension (name);

                        // note: delay doesn't apply when using a key container
                        if (RootContext.StrongNameKeyContainer != null) {
                                an.KeyPair = new StrongNameKeyPair (RootContext.StrongNameKeyContainer);
                                return an;
                        }

                        // strongname is optional
                        if (RootContext.StrongNameKeyFile == null)
                                return an;

                        string AssemblyDir = Path.GetDirectoryName (output);

                        // the StrongName key file may be relative to (a) the compiled
                        // file or (b) to the output assembly. See bugzilla #55320
                        // http://bugzilla.ximian.com/show_bug.cgi?id=55320

                        // (a) relative to the compiled file
                        string filename = Path.GetFullPath (RootContext.StrongNameKeyFile);
                        bool exist = File.Exists (filename);
                        if ((!exist) && (AssemblyDir != null) && (AssemblyDir != String.Empty)) {
                                // (b) relative to the outputed assembly
                                filename = Path.GetFullPath (Path.Combine (AssemblyDir, RootContext.StrongNameKeyFile));
                                exist = File.Exists (filename);
                        }

                        if (exist) {
                                using (FileStream fs = new FileStream (filename, FileMode.Open, FileAccess.Read)) {
                                        byte[] snkeypair = new byte [fs.Length];
                                        fs.Read (snkeypair, 0, snkeypair.Length);

                                        if (RootContext.StrongNameDelaySign) {
                                                // delayed signing - DO NOT include private key
                                                SetPublicKey (an, snkeypair);
                                        }
                                        else {
                                                // no delay so we make sure we have the private key
                                                try {
                                                        CryptoConvert.FromCapiPrivateKeyBlob (snkeypair);
                                                        an.KeyPair = new StrongNameKeyPair (snkeypair);
                                                }
                                                catch (CryptographicException) {
                                                        if (snkeypair.Length == 16) {
                                                                // error # is different for ECMA key
                                                                Report.Error (1606, "Could not sign the assembly. " + 
                                                                        "ECMA key can only be used to delay-sign assemblies");
                                                        }
                                                        else {
                                                                Error_AssemblySigning ("The specified file `" + RootContext.StrongNameKeyFile + "' does not have a private key");
                                                        }
                                                        return null;
                                                }
                                        }
                                }
                        }
                        else {
                                Error_AssemblySigning ("The specified file `" + RootContext.StrongNameKeyFile + "' does not exist");
                                return null;
                        }
                        return an;
                }

                void Error_AssemblySigning (string text)
                {
                        Report.Error (1548, "Error during assembly signing. " + text);
                }

#if GMCS_SOURCE
                bool CheckInternalsVisibleAttribute (Attribute a)
                {
                        string assembly_name = a.GetString ();
                        if (assembly_name.Length == 0)
                                return false;
                                
                        AssemblyName aname = null;
                        try {
                                aname = new AssemblyName (assembly_name);
                        } catch (FileLoadException) {
                        } catch (ArgumentException) {
                        }
                                
                        // Bad assembly name format
                        if (aname == null)
                                Report.Warning (1700, 3, a.Location, "Assembly reference `" + assembly_name + "' is invalid and cannot be resolved");
                        // Report error if we have defined Version or Culture
                        else if (aname.Version != null || aname.CultureInfo != null)
                                throw new Exception ("Friend assembly `" + a.GetString () + 
                                                "' is invalid. InternalsVisibleTo cannot have version or culture specified.");
                        else if (aname.GetPublicKey () == null && Name.GetPublicKey () != null && Name.GetPublicKey ().Length != 0) {
                                Report.Error (1726, a.Location, "Friend assembly reference `" + aname.FullName + "' is invalid." +
                                                " Strong named assemblies must specify a public key in their InternalsVisibleTo declarations");
                                return false;
                        }

                        return true;
                }
#endif

                static bool IsValidAssemblyVersion (string version)
                {
                        Version v;
                        try {
                                v = new Version (version);
                        } catch {
                                try {
                                        int major = int.Parse (version, CultureInfo.InvariantCulture);
                                        v = new Version (major, 0);
                                } catch {
                                        return false;
                                }
                        }

                        foreach (int candidate in new int [] { v.Major, v.Minor, v.Build, v.Revision }) {
                                if (candidate > ushort.MaxValue)
                                        return false;
                        }

                        return true;
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder customBuilder)
                {
                        if (a.IsValidSecurityAttribute ()) {
                                if (declarative_security == null)
                                        declarative_security = new ListDictionary ();

                                a.ExtractSecurityPermissionSet (declarative_security);
                                return;
                        }

                        if (a.Type == TypeManager.assembly_culture_attribute_type) {
                                string value = a.GetString ();
                                if (value == null || value.Length == 0)
                                        return;

                                if (RootContext.Target == Target.Exe) {
                                        a.Error_AttributeEmitError ("The executables cannot be satelite assemblies, remove the attribute or keep it empty");
                                        return;
                                }
                        }

                        if (a.Type == TypeManager.assembly_version_attribute_type) {
                                string value = a.GetString ();
                                if (value == null || value.Length == 0)
                                        return;

                                value = value.Replace ('*', '0');

                                if (!IsValidAssemblyVersion (value)) {
                                        a.Error_AttributeEmitError (string.Format ("Specified version `{0}' is not valid", value));
                                        return;
                                }
                        }

#if GMCS_SOURCE
                        if (a.Type == TypeManager.internals_visible_attr_type && !CheckInternalsVisibleAttribute (a))
                                return;

                        if (a.Type == TypeManager.type_forwarder_attr_type) {
                                Type t = a.GetArgumentType ();
                                if (t == null || TypeManager.HasElementType (t)) {
                                        Report.Error (735, a.Location, "Invalid type specified as an argument for TypeForwardedTo attribute");
                                        return;
                                }

                                if (emitted_forwarders == null) {
                                        emitted_forwarders = new ListDictionary();
                                } else if (emitted_forwarders.Contains(t)) {
                                        Report.SymbolRelatedToPreviousError(((Attribute)emitted_forwarders[t]).Location, null);
                                        Report.Error(739, a.Location, "A duplicate type forward of type `{0}'",
                                                TypeManager.CSharpName(t));
                                        return;
                                }

                                emitted_forwarders.Add(t, a);

                                if (TypeManager.LookupDeclSpace (t) != null) {
                                        Report.SymbolRelatedToPreviousError (t);
                                        Report.Error (729, a.Location, "Cannot forward type `{0}' because it is defined in this assembly",
                                                TypeManager.CSharpName (t));
                                        return;
                                }

                                if (t.IsNested) {
                                        Report.Error (730, a.Location, "Cannot forward type `{0}' because it is a nested type",
                                                TypeManager.CSharpName (t));
                                        return;
                                }

                                if (t.IsGenericType) {
                                        Report.Error (733, a.Location, "Cannot forward generic type `{0}'", TypeManager.CSharpName (t));
                                        return;
                                }

                                if (add_type_forwarder == null) {
                                        add_type_forwarder = typeof (AssemblyBuilder).GetMethod ("AddTypeForwarder",
                                                BindingFlags.NonPublic | BindingFlags.Instance);

                                        if (add_type_forwarder == null) {
                                                Report.RuntimeMissingSupport (a.Location, "TypeForwardedTo attribute");
                                                return;
                                        }
                                }

                                add_type_forwarder.Invoke (Builder, new object[] { t });
                                return;
                        }
                        
                        if (a.Type == TypeManager.extension_attribute_type) {
                                a.Error_MisusedExtensionAttribute ();
                                return;
                        }
#endif
                        Builder.SetCustomAttribute (customBuilder);
                }

                public override void Emit (TypeContainer tc)
                {
                        base.Emit (tc);

#if GMCS_SOURCE
                        if (has_extension_method)
                                Builder.SetCustomAttribute (TypeManager.extension_attribute_attr);
#endif

                        if (runtime_compatibility_attr_type != null) {
                                // FIXME: Does this belong inside SRE.AssemblyBuilder instead?
                                if (OptAttributes == null || !OptAttributes.Contains (runtime_compatibility_attr_type)) {
                                        ConstructorInfo ci = TypeManager.GetPredefinedConstructor (
                                                runtime_compatibility_attr_type, Location.Null, Type.EmptyTypes);
                                        PropertyInfo [] pis = new PropertyInfo [1];
                                        pis [0] = TypeManager.GetPredefinedProperty (runtime_compatibility_attr_type,
                                                "WrapNonExceptionThrows", Location.Null, TypeManager.bool_type);
                                        object [] pargs = new object [1];
                                        pargs [0] = true;
                                        Builder.SetCustomAttribute (new CustomAttributeBuilder (ci, new object [0], pis, pargs));
                                }
                        }

                        if (declarative_security != null) {

                                MethodInfo add_permission = typeof (AssemblyBuilder).GetMethod ("AddPermissionRequests", BindingFlags.Instance | BindingFlags.NonPublic);
                                object builder_instance = Builder;

                                try {
                                        // Microsoft runtime hacking
                                        if (add_permission == null) {
                                                Type assembly_builder = typeof (AssemblyBuilder).Assembly.GetType ("System.Reflection.Emit.AssemblyBuilderData");
                                                add_permission = assembly_builder.GetMethod ("AddPermissionRequests", BindingFlags.Instance | BindingFlags.NonPublic);

                                                FieldInfo fi = typeof (AssemblyBuilder).GetField ("m_assemblyData", BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.GetField);
                                                builder_instance = fi.GetValue (Builder);
                                        }

                                        object[] args = new object [] { declarative_security [SecurityAction.RequestMinimum],
                                                                                                  declarative_security [SecurityAction.RequestOptional],
                                                                                                  declarative_security [SecurityAction.RequestRefuse] };
                                        add_permission.Invoke (builder_instance, args);
                                }
                                catch {
                                        Report.RuntimeMissingSupport (Location.Null, "assembly permission setting");
                                }
                        }
                }

                public override string[] ValidAttributeTargets {
                        get {
                                return attribute_targets;
                        }
                }

                // Wrapper for AssemblyBuilder.AddModule
                static MethodInfo adder_method;
                static public MethodInfo AddModule_Method {
                        get {
                                if (adder_method == null)
                                        adder_method = typeof (AssemblyBuilder).GetMethod ("AddModule", BindingFlags.Instance|BindingFlags.NonPublic);
                                return adder_method;
                        }
                }
                public Module AddModule (string module)
                {
                        MethodInfo m = AddModule_Method;
                        if (m == null) {
                                Report.RuntimeMissingSupport (Location.Null, "/addmodule");
                                Environment.Exit (1);
                        }

                        try {
                                return (Module) m.Invoke (Builder, new object [] { module });
                        } catch (TargetInvocationException ex) {
                                throw ex.InnerException;
                        }
                }               
        }

        public class ModuleClass : CommonAssemblyModulClass {
                // TODO: make it private and move all builder based methods here
                public ModuleBuilder Builder;
                bool m_module_is_unsafe;
#if GMCS_SOURCE         
                bool has_default_charset;
#endif          

                public CharSet DefaultCharSet = CharSet.Ansi;
                public TypeAttributes DefaultCharSetType = TypeAttributes.AnsiClass;

                static string[] attribute_targets = new string [] { "module" };

                public ModuleClass (bool is_unsafe)
                {
                        m_module_is_unsafe = is_unsafe;
                }

                public override AttributeTargets AttributeTargets {
                        get {
                                return AttributeTargets.Module;
                        }
                }

                public override bool IsClsComplianceRequired ()
                {
                        return CodeGen.Assembly.IsClsCompliant;
                }

                public override void Emit (TypeContainer tc) 
                {
                        base.Emit (tc);

                        if (m_module_is_unsafe) {
                                Type t = TypeManager.CoreLookupType ("System.Security", "UnverifiableCodeAttribute", Kind.Class, true);
                                if (t != null) {
                                        ConstructorInfo unverifiable_code_ctor = TypeManager.GetPredefinedConstructor (t, Location.Null, Type.EmptyTypes);
                                        if (unverifiable_code_ctor != null)
                                                Builder.SetCustomAttribute (new CustomAttributeBuilder (unverifiable_code_ctor, new object [0]));
                                }
                        }
                }
                
                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder customBuilder)
                {
                        if (a.Type == TypeManager.cls_compliant_attribute_type) {
                                if (CodeGen.Assembly.ClsCompliantAttribute == null) {
                                        Report.Warning (3012, 1, a.Location, "You must specify the CLSCompliant attribute on the assembly, not the module, to enable CLS compliance checking");
                                }
                                else if (CodeGen.Assembly.IsClsCompliant != a.GetBoolean ()) {
                                        Report.SymbolRelatedToPreviousError (CodeGen.Assembly.ClsCompliantAttribute.Location, CodeGen.Assembly.ClsCompliantAttribute.GetSignatureForError ());
                                        Report.Warning (3017, 1, a.Location, "You cannot specify the CLSCompliant attribute on a module that differs from the CLSCompliant attribute on the assembly");
                                        return;
                                }
                        }

                        Builder.SetCustomAttribute (customBuilder);
                }

                public bool HasDefaultCharSet {
                        get {
#if GMCS_SOURCE         
                                return has_default_charset;
#else
                                return false;
#endif                                                          
                        }
                }

                /// <summary>
                /// It is called very early therefore can resolve only predefined attributes
                /// </summary>
                public void Resolve ()
                {
#if GMCS_SOURCE
                        if (OptAttributes == null)
                                return;

                        if (!OptAttributes.CheckTargets())
                                return;

                        if (TypeManager.default_charset_type == null)
                                return;

                        Attribute a = ResolveAttribute (TypeManager.default_charset_type);
                        if (a != null) {
                                has_default_charset = true;
                                DefaultCharSet = a.GetCharSetValue ();
                                switch (DefaultCharSet) {
                                case CharSet.Ansi:
                                case CharSet.None:
                                        break;
                                case CharSet.Auto:
                                        DefaultCharSetType = TypeAttributes.AutoClass;
                                        break;
                                case CharSet.Unicode:
                                        DefaultCharSetType = TypeAttributes.UnicodeClass;
                                        break;
                                default:
                                        Report.Error (1724, a.Location, "Value specified for the argument to 'System.Runtime.InteropServices.DefaultCharSetAttribute' is not valid");
                                        break;
                                }
                        }
#endif
                }

                public override string[] ValidAttributeTargets {
                        get {
                                return attribute_targets;
                        }
                }
        }
}