C# Field.Define方法代碼示例

		public override bool Define()
		{
			var mod_flags_src = ModFlags;

			if (!base.Define ())
				return false;

			if (declarators != null) {
				if ((mod_flags_src & Modifiers.DEFAULT_ACCESS_MODIFER) != 0)
					mod_flags_src &= ~(Modifiers.AccessibilityMask | Modifiers.DEFAULT_ACCESS_MODIFER);

				var t = new TypeExpression (MemberType, TypeExpression.Location);
				foreach (var d in declarators) {
					var ef = new EventField (Parent, t, mod_flags_src, new MemberName (d.Name.Value, d.Name.Location), OptAttributes);

					if (d.Initializer != null)
						ef.initializer = d.Initializer;

					ef.Define ();
					Parent.PartialContainer.Members.Add (ef);
				}
			}

			if (!HasBackingField) {
				SetIsUsed ();
				return true;
			}

			if (Add.IsInterfaceImplementation)
				SetIsUsed ();

			backing_field = new Field (Parent,
				new TypeExpression (MemberType, Location),
				Modifiers.BACKING_FIELD | Modifiers.COMPILER_GENERATED | Modifiers.PRIVATE | (ModFlags & (Modifiers.STATIC | Modifiers.UNSAFE)),
				MemberName, null);

			Parent.PartialContainer.Members.Add (backing_field);
			backing_field.Initializer = Initializer;
			backing_field.ModFlags &= ~Modifiers.COMPILER_GENERATED;

			// Call define because we passed fields definition
			backing_field.Define ();

			// Set backing field for event fields
			spec.BackingField = backing_field.Spec;

			return true;
		}

		public override void Emit (EmitContext ec)
		{
			//
			// Use same anonymous method implementation for scenarios where same
			// code is used from multiple blocks, e.g. field initializers
			//
			if (method == null) {
				//
				// Delay an anonymous method definition to avoid emitting unused code
				// for unreachable blocks or expression trees
				//
				method = DoCreateMethodHost (ec);
				method.Define ();
			}

			bool is_static = (method.ModFlags & Modifiers.STATIC) != 0;
			if (is_static && am_cache == null) {
				//
				// Creates a field cache to store delegate instance if it's not generic
				//
				if (!method.MemberName.IsGeneric) {
					var parent = method.Parent.PartialContainer;
					int id = parent.AnonymousMethodsCounter++;
					var cache_type = storey != null && storey.Mutator != null ? storey.Mutator.Mutate (type) : type;

					am_cache = new Field (parent, new TypeExpression (cache_type, loc),
						Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
						new MemberName (CompilerGeneratedContainer.MakeName (null, "f", "am$cache", id), loc), null);
					am_cache.Define ();
					parent.AddField (am_cache);
				} else {
					// TODO: Implement caching of generated generic static methods
					//
					// Idea:
					//
					// Some extra class is needed to capture variable generic type
					// arguments. Maybe we could re-use anonymous types, with a unique
					// anonymous method id, but they are quite heavy.
					//
					// Consider : "() => typeof(T);"
					//
					// We need something like
					// static class Wrap<Tn, Tm, DelegateType> {
					//		public static DelegateType cache;
					// }
					//
					// We then specialize local variable to capture all generic parameters
					// and delegate type, e.g. "Wrap<Ta, Tb, DelegateTypeInst> cache;"
					//
				}
			}

			Label l_initialized = ec.DefineLabel ();

			if (am_cache != null) {
				ec.Emit (OpCodes.Ldsfld, am_cache.Spec);
				ec.Emit (OpCodes.Brtrue_S, l_initialized);
			}

			//
			// Load method delegate implementation
			//

			if (is_static) {
				ec.EmitNull ();
			} else if (storey != null) {
				Expression e = storey.GetStoreyInstanceExpression (ec).Resolve (new ResolveContext (ec.MemberContext));
				if (e != null) {
					e.Emit (ec);
				}
			} else {
				ec.EmitThis ();

				//
				// Special case for value type storey where this is not lifted but
				// droped off to parent class
				//
				for (var b = Block.Parent; b != null; b = b.Parent) {
					if (b.ParametersBlock.StateMachine != null) {
						ec.Emit (OpCodes.Ldfld, b.ParametersBlock.StateMachine.HoistedThis.Field.Spec);
						break;
					}
				}
			}

			var delegate_method = method.Spec;
			if (storey != null && storey.MemberName.IsGeneric) {
				TypeSpec t = storey.Instance.Type;

				//
				// Mutate anonymous method instance type if we are in nested
				// hoisted generic anonymous method storey
				//
				if (ec.IsAnonymousStoreyMutateRequired) {
					t = storey.Mutator.Mutate (t);
				}

				ec.Emit (OpCodes.Ldftn, TypeBuilder.GetMethod (t.GetMetaInfo (), (MethodInfo) delegate_method.GetMetaInfo ()));
			} else {
				if (delegate_method.IsGeneric)
//.........這裏部分代碼省略.........

		protected override Expression DoResolve (ResolveContext ec)
		{
			var expr = base.DoResolve (ec);
			if (expr == null)
				return ErrorExpression.Instance;

			if (ec.IsInProbingMode)
				return expr;

			//
			// Cache any static delegate creation
			//
			if (method_group.InstanceExpression != null)
				return expr;

			//
			// Cannot easily cache types with MVAR
			//
			if (!HasMvar ())
				return expr;

			//
			// Create type level cache for a delegate instance
			//
			var parent = ec.CurrentMemberDefinition.Parent.PartialContainer;
			int id = parent.MethodGroupsCounter++;

			mg_cache = new Field (parent, new TypeExpression (type, loc),
				Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
				new MemberName (CompilerGeneratedContainer.MakeName (null, "f", "mg$cache", id), loc), null);
			mg_cache.Define ();
			parent.AddField (mg_cache);

			return expr;
		}

        static Field CreateSiteField(FullNamedExpression type)
        {
            TypeContainer site_container = CreateSiteContainer ();
            Field f = new Field (site_container, type, Modifiers.PUBLIC | Modifiers.STATIC,
                new MemberName ("Site" +  field_counter++), null);
            f.Define ();

            site_container.AddField (f);
            return f;
        }

		void CreateAutomaticProperty ()
		{
			// Create backing field
			backing_field = new BackingField (this);
			if (!backing_field.Define ())
				return;

			Parent.PartialContainer.Members.Add (backing_field);

			FieldExpr fe = new FieldExpr (backing_field, Location);
			if ((backing_field.ModFlags & Modifiers.STATIC) == 0)
				fe.InstanceExpression = new CompilerGeneratedThis (Parent.CurrentType, Location);

			//
			// Create get block but we careful with location to
			// emit only single sequence point per accessor. This allow
			// to set a breakpoint on it even with no user code
			//
			Get.Block = new ToplevelBlock (Compiler, ParametersCompiled.EmptyReadOnlyParameters, Location.Null);
			Return r = new Return (fe, Get.Location);
			Get.Block.AddStatement (r);

			// Create set block
			Set.Block = new ToplevelBlock (Compiler, Set.ParameterInfo, Location.Null);
			Assign a = new SimpleAssign (fe, new SimpleName ("value", Location.Null), Location.Null);
			Set.Block.AddStatement (new StatementExpression (a, Set.Location));
		}

		public override bool Define()
		{
			if (!base.Define ())
				return false;

			if (declarators != null) {
				var t = new TypeExpression (MemberType, TypeExpression.Location);
				int index = Parent.PartialContainer.Events.IndexOf (this);
				foreach (var d in declarators) {
					var ef = new EventField (Parent, t, ModFlags, new MemberName (d.Name.Value, d.Name.Location), OptAttributes);

					if (d.Initializer != null)
						ef.initializer = d.Initializer;

					Parent.PartialContainer.Events.Insert (++index, ef);
				}
			}

			if (!HasBackingField) {
				SetIsUsed ();
				return true;
			}

			if (Add.IsInterfaceImplementation)
				SetIsUsed ();

			backing_field = new Field (Parent,
				new TypeExpression (MemberType, Location),
				Modifiers.BACKING_FIELD | Modifiers.COMPILER_GENERATED | Modifiers.PRIVATE | (ModFlags & (Modifiers.STATIC | Modifiers.UNSAFE)),
				MemberName, null);

			Parent.PartialContainer.AddField (backing_field);
			backing_field.Initializer = Initializer;
			backing_field.ModFlags &= ~Modifiers.COMPILER_GENERATED;

			// Call define because we passed fields definition
			backing_field.Define ();

			// Set backing field for event fields
			spec.BackingField = backing_field.Spec;

			return true;
		}

		void CreateEvaluatorVariable (BlockContext bc, LocalVariable li)
		{
			var container = bc.CurrentMemberDefinition.Parent;

			Field f = new Field (container, new TypeExpression (li.Type, li.Location), Modifiers.PUBLIC | Modifiers.STATIC,
				new MemberName (li.Name, li.Location), null);

			container.AddField (f);
			f.Define ();
			Evaluator.QueueField (f);

			li.HoistedVariant = new HoistedEvaluatorVariable (f);
			li.SetIsUsed ();
		}

		void ResolveStringSwitchMap (ResolveContext ec)
		{
			FullNamedExpression string_dictionary_type;
			if (TypeManager.generic_ienumerable_type != null) {
				MemberAccess system_collections_generic = new MemberAccess (new MemberAccess (
					new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Collections", loc), "Generic", loc);

				string_dictionary_type = new MemberAccess (system_collections_generic, "Dictionary",
					new TypeArguments (
						new TypeExpression (TypeManager.string_type, loc),
						new TypeExpression (TypeManager.int32_type, loc)), loc);
			} else {
				MemberAccess system_collections_generic = new MemberAccess (
					new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Collections", loc);

				string_dictionary_type = new MemberAccess (system_collections_generic, "Hashtable", loc);
			}

			var ctype = ec.CurrentMemberDefinition.Parent.PartialContainer;
			Field field = new Field (ctype, string_dictionary_type,
				Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
				new MemberName (CompilerGeneratedClass.MakeName (null, "f", "switch$map", unique_counter++), loc), null);
			if (!field.Define ())
				return;
			ctype.AddField (field);

			var init = new List<Expression> ();
			int counter = 0;
			Elements.Clear ();
			string value = null;
			foreach (SwitchSection section in Sections) {
				int last_count = init.Count;
				foreach (SwitchLabel sl in section.Labels) {
					if (sl.Label == null || sl.Converted == SwitchLabel.NullStringCase)
						continue;

					value = (string) sl.Converted;
					var init_args = new List<Expression> (2);
					init_args.Add (new StringLiteral (value, sl.Location));
					init_args.Add (new IntConstant (counter, loc));
					init.Add (new CollectionElementInitializer (init_args, loc));
				}

				//
				// Don't add empty sections
				//
				if (last_count == init.Count)
					continue;

				Elements.Add (counter, section.Labels [0]);
				++counter;
			}

			Arguments args = new Arguments (1);
			args.Add (new Argument (new IntConstant (init.Count, loc)));
			Expression initializer = new NewInitialize (string_dictionary_type, args,
				new CollectionOrObjectInitializers (init, loc), loc);

			switch_cache_field = new FieldExpr (field, loc);
			string_dictionary = new SimpleAssign (switch_cache_field, initializer.Resolve (ec));
		}

		public override bool Define ()
		{
			if (!base.Define ())
				return false;

			MetaType[] required_modifier = null;
			if ((ModFlags & Modifiers.VOLATILE) != 0) {
				var mod = Module.PredefinedTypes.IsVolatile.Resolve ();
				if (mod != null)
					required_modifier = new MetaType[] { mod.GetMetaInfo () };
			}

			FieldBuilder = Parent.TypeBuilder.DefineField (
				Name, member_type.GetMetaInfo (), required_modifier, null, ModifiersExtensions.FieldAttr (ModFlags));

			spec = new FieldSpec (Parent.Definition, this, MemberType, FieldBuilder, ModFlags);

			//
			// Don't cache inaccessible fields except for struct where we
			// need them for definitive assignment checks
			//
			if ((ModFlags & Modifiers.BACKING_FIELD) == 0 || Parent.Kind == MemberKind.Struct) {
				Parent.MemberCache.AddMember (spec);
			}

			if (initializer != null) {
				Parent.RegisterFieldForInitialization (this, new FieldInitializer (this, initializer, TypeExpression.Location));
			}

			if (declarators != null) {
				foreach (var d in declarators) {
					var t = new TypeExpression (MemberType, d.Name.Location);
					var f = new Field (Parent, t, ModFlags, new MemberName (d.Name.Value, d.Name.Location), OptAttributes);
					if (d.Initializer != null)
						f.initializer = d.Initializer;

					f.Define ();
					Parent.PartialContainer.Members.Add (f);
				}
			}

			return true;
		}

        public override Expression DoResolveLValue(ResolveContext ec, Expression right_side)
        {
            Expression ret = base.DoResolveLValue (ec, right_side);
            if (ret == null)
                return null;

            Field f = new Field (container, new TypeExpression (ret.Type, Location),
                         Modifiers.PUBLIC | Modifiers.STATIC,
                         new MemberName (name, Location), null);
            container.AddField (f);
            if (f.Define ())
                Evaluator.QueueField (f);

            return ret;
        }

		public override void Emit (EmitContext ec)
		{
			//
			// Use same anonymous method implementation for scenarios where same
			// code is used from multiple blocks, e.g. field initializers
			//
			if (method == null) {
				//
				// Delay an anonymous method definition to avoid emitting unused code
				// for unreachable blocks or expression trees
				//
				method = DoCreateMethodHost (ec);
				method.Define ();
			}

			bool is_static = (method.ModFlags & Modifiers.STATIC) != 0;
			if (is_static && am_cache == null) {
				//
				// Creates a field cache to store delegate instance if it's not generic
				//
				if (!method.MemberName.IsGeneric) {
					TypeContainer parent = method.Parent.PartialContainer;
					int id = parent.Fields == null ? 0 : parent.Fields.Count;
					am_cache = new Field (parent, new TypeExpression (type, loc),
						Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
						new MemberName (CompilerGeneratedClass.MakeName (null, "f", "am$cache", id), loc), null);
					am_cache.Define ();
					parent.AddField (am_cache);
				} else {
					// TODO: Implement caching of generated generic static methods
					//
					// Idea:
					//
					// Some extra class is needed to capture variable generic type
					// arguments. Maybe we could re-use anonymous types, with a unique
					// anonymous method id, but they are quite heavy.
					//
					// Consider : "() => typeof(T);"
					//
					// We need something like
					// static class Wrap<Tn, Tm, DelegateType> {
					//		public static DelegateType cache;
					// }
					//
					// We then specialize local variable to capture all generic parameters
					// and delegate type, e.g. "Wrap<Ta, Tb, DelegateTypeInst> cache;"
					//
				}
			}

			ILGenerator ig = ec.ig;
			Label l_initialized = ig.DefineLabel ();

			if (am_cache != null) {
				ig.Emit (OpCodes.Ldsfld, am_cache.FieldBuilder);
				ig.Emit (OpCodes.Brtrue_S, l_initialized);
			}

			//
			// Load method delegate implementation
			//

			if (is_static) {
				ig.Emit (OpCodes.Ldnull);
			} else if (storey != null) {
				Expression e = storey.GetStoreyInstanceExpression (ec).Resolve (new ResolveContext (ec.MemberContext));
				if (e != null)
					e.Emit (ec);
			} else {
				ig.Emit (OpCodes.Ldarg_0);
			}

			MethodInfo delegate_method = method.MethodBuilder;
			if (storey != null && storey.MemberName.IsGeneric) {
				Type t = storey.Instance.Type;
				
				//
				// Mutate anonymous method instance type if we are in nested
				// hoisted generic anonymous method storey
				//
				if (ec.CurrentAnonymousMethod != null &&
					ec.CurrentAnonymousMethod.Storey != null &&
					ec.CurrentAnonymousMethod.Storey.IsGeneric) {
					t = storey.GetGenericStorey ().MutateType (t);
				}

#if GMCS_SOURCE
				delegate_method = TypeBuilder.GetMethod (t, delegate_method);
#else
				throw new NotSupportedException ();
#endif
			}

			ig.Emit (OpCodes.Ldftn, delegate_method);

			ConstructorInfo constructor_method = Delegate.GetConstructor (RootContext.ToplevelTypes.Compiler, ec.CurrentType, type);
#if MS_COMPATIBLE
            if (type.IsGenericType && type is TypeBuilder)
                constructor_method = TypeBuilder.GetConstructor (type, constructor_method);
#endif
//.........這裏部分代碼省略.........

		void ResolveStringSwitchMap (EmitContext ec)
		{
			FullNamedExpression string_dictionary_type;
#if GMCS_SOURCE
			MemberAccess system_collections_generic = new MemberAccess (new MemberAccess (
				new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Collections", loc), "Generic", loc);

			string_dictionary_type = new MemberAccess (system_collections_generic, "Dictionary",
				new TypeArguments (
					new TypeExpression (TypeManager.string_type, loc),
					new TypeExpression (TypeManager.int32_type, loc)), loc);
#else
			MemberAccess system_collections_generic = new MemberAccess (
				new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Collections", loc);

			string_dictionary_type = new MemberAccess (system_collections_generic, "Hashtable", loc);
#endif
			Field field = new Field (ec.TypeContainer, string_dictionary_type,
				Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
				new MemberName (CompilerGeneratedClass.MakeName (null, "f", "switch$map", unique_counter++), loc), null);
			if (!field.Define ())
				return;
			ec.TypeContainer.PartialContainer.AddField (field);

			ArrayList init = new ArrayList ();
			int counter = 0;
			Elements.Clear ();
			string value = null;
			foreach (SwitchSection section in Sections) {
				foreach (SwitchLabel sl in section.Labels) {
					if (sl.Label == null || sl.Converted == SwitchLabel.NullStringCase) {
						value = null;
						continue;
					}

					value = (string) sl.Converted;
					ArrayList init_args = new ArrayList (2);
					init_args.Add (new StringLiteral (value, sl.Location));
					init_args.Add (new IntConstant (counter, loc));
					init.Add (new CollectionElementInitializer (init_args, loc));
				}

				if (value == null)
					continue;

				Elements.Add (counter, section.Labels [0]);
				++counter;
			}

			ArrayList args = new ArrayList (1);
			args.Add (new Argument (new IntConstant (Sections.Count, loc)));
			Expression initializer = new NewInitialize (string_dictionary_type, args,
				new CollectionOrObjectInitializers (init, loc), loc);

			switch_cache_field = new FieldExpr (field.FieldBuilder, loc);
			string_dictionary = new SimpleAssign (switch_cache_field, initializer.Resolve (ec));
		}

        public override bool Define()
        {
            if (!base.Define ())
                return false;

            if (Initializer != null && (ModFlags & Modifiers.ABSTRACT) != 0) {
                Report.Error (74, Location, "`{0}': abstract event cannot have an initializer",
                    GetSignatureForError ());
            }

            if (!HasBackingField) {
                SetIsUsed ();
                return true;
            }

            // FIXME: We are unable to detect whether generic event is used because
            // we are using FieldExpr instead of EventExpr for event access in that
            // case.  When this issue will be fixed this hack can be removed.
            if (TypeManager.IsGenericType (MemberType) || Parent.IsGeneric)
                SetIsUsed ();

            if (Add.IsInterfaceImplementation)
                SetIsUsed ();

            BackingField = new Field (Parent,
                new TypeExpression (MemberType, Location),
                Modifiers.BACKING_FIELD | Modifiers.COMPILER_GENERATED | Modifiers.PRIVATE | (ModFlags & (Modifiers.STATIC | Modifiers.UNSAFE)),
                MemberName, null);

            Parent.PartialContainer.AddField (BackingField);
            BackingField.Initializer = Initializer;
            BackingField.ModFlags &= ~Modifiers.COMPILER_GENERATED;

            // Call define because we passed fields definition
            return BackingField.Define ();
        }