2009-01-02 Ivan N. Zlatev <contact@i-nz.net>
[mono.git] / mcs / mcs / const.cs
index 5f90e75170debe3e622a6726083324db477172e6..1f082adb94bee259b43431e0a123ac1446d66985 100644 (file)
@@ -5,8 +5,8 @@
 //   Miguel de Icaza (miguel@ximian.com)
 //   Marek Safar (marek.safar@seznam.cz)
 //
-// (C) 2001 Ximian, Inc.
-//
+// Copyright 2001-2003 Ximian, Inc.
+// Copyright 2003-2008 Novell, Inc.
 //
 
 namespace Mono.CSharp {
@@ -20,12 +20,14 @@ namespace Mono.CSharp {
        {
                void CheckObsoleteness (Location loc);
                bool ResolveValue ();
-               Constant Value { get; }
+               Constant CreateConstantReference (Location loc);
        }
 
-       public class Const : FieldMember, IConstant {
-               Constant value;
+       public class Const : FieldBase, IConstant {
+               protected Constant value;
                bool in_transit;
+               bool resolved;
+               bool define_called;
 
                public const int AllowedModifiers =
                        Modifiers.NEW |
@@ -34,9 +36,9 @@ namespace Mono.CSharp {
                        Modifiers.INTERNAL |
                        Modifiers.PRIVATE;
 
-               public Const (TypeContainer parent, Expression constant_type, string name,
+               public Const (DeclSpace parent, FullNamedExpression type, string name,
                              Expression expr, int mod_flags, Attributes attrs, Location loc)
-                       : base (parent, constant_type, mod_flags, AllowedModifiers,
+                       : base (parent, type, mod_flags, AllowedModifiers,
                                new MemberName (name, loc), attrs)
                {
                        initializer = expr;
@@ -48,7 +50,7 @@ namespace Mono.CSharp {
                        // Constant.Define can be called when the parent type hasn't yet been populated
                        // and it's base types need not have been populated.  So, we defer this check
                        // to the second time Define () is called on this member.
-                       if (Parent.BaseCache == null)
+                       if (Parent.PartialContainer.BaseCache == null)
                                return true;
                        return base.CheckBase ();
                }
@@ -58,34 +60,60 @@ namespace Mono.CSharp {
                /// </summary>
                public override bool Define ()
                {
-                       // Make Define () idempotent, but ensure that the error check happens.
-                       if (FieldBuilder != null)
-                               return base.CheckBase ();
+                       // Because constant define can be called from other class
+                       if (define_called) {
+                               CheckBase ();
+                               return FieldBuilder != null;
+                       }
+
+                       define_called = true;
 
                        if (!base.Define ())
                                return false;
 
                        Type ttype = MemberType;
-                       while (ttype.IsArray)
-                           ttype = TypeManager.GetElementType (ttype);
+                       if (!IsConstantTypeValid (ttype)) {
+                               Error_InvalidConstantType (ttype, Location);
+                       }
+
+                       // If the constant is private then we don't need any field the
+                       // value is already inlined and cannot be referenced
+                       //if ((ModFlags & Modifiers.PRIVATE) != 0 && RootContext.Optimize)
+                       //      return true;
 
                        FieldAttributes field_attr = FieldAttributes.Static | Modifiers.FieldAttr (ModFlags);
                        // Decimals cannot be emitted into the constant blob.  So, convert to 'readonly'.
                        if (ttype == TypeManager.decimal_type) {
                                field_attr |= FieldAttributes.InitOnly;
-                               Parent.RegisterFieldForInitialization (this);
-                       }
-                       else {
+                       } else {
                                field_attr |= FieldAttributes.Literal;
                        }
 
                        FieldBuilder = Parent.TypeBuilder.DefineField (Name, MemberType, field_attr);
-
                        TypeManager.RegisterConstant (FieldBuilder, this);
+                       Parent.MemberCache.AddMember (FieldBuilder, this);
+
+                       if ((field_attr & FieldAttributes.InitOnly) != 0)
+                               Parent.PartialContainer.RegisterFieldForInitialization (this,
+                                       new FieldInitializer (FieldBuilder, initializer, this));
+
+                       return true;
+               }
+
+               public static bool IsConstantTypeValid (Type t)
+               {
+                       if (TypeManager.IsBuiltinOrEnum (t))
+                               return true;
+
+                       if (t.IsPointer || t.IsValueType)
+                               return false;
+                       
+                       if (TypeManager.IsGenericParameter (t))
+                               return false;
 
                        return true;
                }
-               
+
                /// <summary>
                ///  Emits the field value by evaluating the expression
                /// </summary>
@@ -94,20 +122,52 @@ namespace Mono.CSharp {
                        if (!ResolveValue ())
                                return;
 
+                       if (FieldBuilder == null)
+                               return;
+
                        if (value.Type == TypeManager.decimal_type) {
-                               Decimal d = ((DecimalConstant)value).Value;
-                               int[] bits = Decimal.GetBits (d);
-                               object[] args = new object[] { (byte)(bits [3] >> 16), (byte)(bits [3] >> 31), (uint)bits [2], (uint)bits [1], (uint)bits [0] };
-                               CustomAttributeBuilder cab = new CustomAttributeBuilder (TypeManager.decimal_constant_attribute_ctor, args);
-                               FieldBuilder.SetCustomAttribute (cab);
-                       }
-                       else{
+                               EmitDecimalConstant ();
+                       } else{
                                FieldBuilder.SetConstant (value.GetTypedValue ());
                        }
 
                        base.Emit ();
                }
 
+               void EmitDecimalConstant ()
+               {
+                       ConstructorInfo ctor = TypeManager.decimal_constant_attribute_ctor;
+                       if (ctor == null) {
+                               if (TypeManager.decimal_constant_attribute_type == null) {
+                                       TypeManager.decimal_constant_attribute_type = TypeManager.CoreLookupType (
+                                               "System.Runtime.CompilerServices", "DecimalConstantAttribute", Kind.Class, true);
+
+                                       if (TypeManager.decimal_constant_attribute_type == null)
+                                               return;
+                               }
+
+                               ctor = TypeManager.GetPredefinedConstructor (TypeManager.decimal_constant_attribute_type, Location,
+                                       TypeManager.byte_type, TypeManager.byte_type,
+                                       TypeManager.uint32_type, TypeManager.uint32_type, TypeManager.uint32_type);
+
+                               if (ctor == null)
+                                       return;
+
+                               TypeManager.decimal_constant_attribute_ctor = ctor;
+                       }
+
+                       Decimal d = ((DecimalConstant) value).Value;
+                       int [] bits = Decimal.GetBits (d);
+                       object [] args = new object [] { 
+                               (byte) (bits [3] >> 16),
+                               (byte) (bits [3] >> 31),
+                               (uint) bits [2], (uint) bits [1], (uint) bits [0]
+                       };
+
+                       CustomAttributeBuilder cab = new CustomAttributeBuilder (ctor, args);
+                       FieldBuilder.SetCustomAttribute (cab);
+               }
+
                public static void Error_ExpressionMustBeConstant (Location loc, string e_name)
                {
                        Report.Error (133, loc, "The expression being assigned to `{0}' must be constant", e_name);
@@ -119,47 +179,68 @@ namespace Mono.CSharp {
                                mc.GetSignatureForError ());
                }
 
+               public static void Error_ConstantCanBeInitializedWithNullOnly (Type type, Location loc, string name)
+               {
+                       Report.Error (134, loc, "A constant `{0}' of reference type `{1}' can only be initialized with null",
+                               name, TypeManager.CSharpName (type));
+               }
+
+               public static void Error_InvalidConstantType (Type t, Location loc)
+               {
+                       Report.Error (283, loc, "The type `{0}' cannot be declared const", TypeManager.CSharpName (t));
+               }
+
                #region IConstant Members
 
                public bool ResolveValue ()
                {
-                       if (value != null)
-                               return true;
+                       if (resolved)
+                               return value != null;
 
                        SetMemberIsUsed ();
                        if (in_transit) {
                                Error_CyclicDeclaration (this);
                                // Suppress cyclic errors
                                value = New.Constantify (MemberType);
+                               resolved = true;
                                return false;
                        }
 
                        in_transit = true;
                        // TODO: IResolveContext here
-                       EmitContext ec = new EmitContext (this, Parent, Location, null, MemberType, ModFlags);
-                       value = initializer.ResolveAsConstant (ec, this);
+                       EmitContext ec = new EmitContext (
+                               this, Parent, Location, null, MemberType, ModFlags);
+                       ec.InEnumContext = this is EnumMember;
+                       ec.IsAnonymousMethodAllowed = false;
+                       value = DoResolveValue (ec);
                        in_transit = false;
+                       resolved = true;
+                       return value != null;
+               }
 
+               protected virtual Constant DoResolveValue (EmitContext ec)
+               {
+                       Constant value = initializer.ResolveAsConstant (ec, this);
                        if (value == null)
-                               return false;
-
-                       value = value.ToType (MemberType, Location);
-                       if (value == null)
-                               return false;
+                               return null;
 
-                       if (!MemberType.IsValueType && MemberType != TypeManager.string_type && !value.IsDefaultValue) {
-                               Report.Error (134, Location, "`{0}': A const of reference other than string can only be initialized with null",
-                                       GetSignatureForError ());
-                               return false;
+                       Constant c = value.ConvertImplicitly (MemberType);
+                       if (c == null) {
+                               if (TypeManager.IsReferenceType (MemberType))
+                                       Error_ConstantCanBeInitializedWithNullOnly (MemberType, Location, GetSignatureForError ());
+                               else
+                                       value.Error_ValueCannotBeConverted (ec, Location, MemberType, false);
                        }
 
-                       return true;
+                       return c;
                }
 
-               public Constant Value {
-                       get {
-                               return value;
-                       }
+               public virtual Constant CreateConstantReference (Location loc)
+               {
+                       if (value == null)
+                               return null;
+
+                       return Constant.CreateConstant (value.Type, value.GetValue(), loc);
                }
 
                #endregion
@@ -168,14 +249,14 @@ namespace Mono.CSharp {
        public class ExternalConstant : IConstant
        {
                FieldInfo fi;
-               Constant value;
+               object value;
 
                public ExternalConstant (FieldInfo fi)
                {
                        this.fi = fi;
                }
 
-               private ExternalConstant (FieldInfo fi, Constant value):
+               private ExternalConstant (FieldInfo fi, object value):
                        this (fi)
                {
                        this.value = value;
@@ -190,13 +271,16 @@ namespace Mono.CSharp {
                {
                        if (fi is FieldBuilder)
                                return null;
-                       
+
+                       if (TypeManager.decimal_constant_attribute_type == null)
+                               return null;
+
                        object[] attrs = fi.GetCustomAttributes (TypeManager.decimal_constant_attribute_type, false);
                        if (attrs.Length != 1)
                                return null;
 
                        IConstant ic = new ExternalConstant (fi,
-                               new DecimalConstant (((System.Runtime.CompilerServices.DecimalConstantAttribute) attrs [0]).Value, Location.Null));
+                               ((System.Runtime.CompilerServices.DecimalConstantAttribute) attrs [0]).Value);
 
                        return ic;
                }
@@ -218,20 +302,13 @@ namespace Mono.CSharp {
                        if (value != null)
                                return true;
 
-                       if (fi.DeclaringType.IsEnum) {
-                               value = Expression.Constantify (fi.GetValue (fi), TypeManager.EnumToUnderlying (fi.FieldType));
-                               value = new EnumConstant (value, fi.DeclaringType);
-                               return true;
-                       }
-
-                       value = Expression.Constantify (fi.GetValue (fi), fi.FieldType);
+                       value = fi.GetValue (fi);
                        return true;
                }
 
-               public Constant Value {
-                       get {
-                               return value;
-                       }
+               public Constant CreateConstantReference (Location loc)
+               {
+                       return Constant.CreateConstant (TypeManager.TypeToCoreType (fi.FieldType), value, loc);
                }
 
                #endregion