2009-03-17 Marek Safar <marek.safar@gmail.com>
[mono.git] / mcs / mcs / assign.cs
index 25a56936ad3cbcc1dd2d145ee45b2a2d774f01ed..19a5e7e6dac9d5137a87f225cf383d69ef9d4768 100644 (file)
@@ -4,13 +4,17 @@
 // Author:
 //   Miguel de Icaza (miguel@ximian.com)
 //   Martin Baulig (martin@ximian.com)
+//   Marek Safar (marek.safar@gmail.com)       
 //
-// (C) 2001, 2002, 2003 Ximian, Inc.
-// (C) 2004 Novell, Inc
+// Dual licensed under the terms of the MIT X11 or GNU GPL
+//
+// Copyright 2001, 2002, 2003 Ximian, Inc.
+// Copyright 2004-2008 Novell, Inc
 //
 using System;
 using System.Reflection;
 using System.Reflection.Emit;
+using System.Collections;
 
 namespace Mono.CSharp {
 
@@ -175,7 +179,7 @@ namespace Mono.CSharp {
        ///   The `is_address' stuff is really just a hack. We need to come up with a better
        ///   way to handle it.
        /// </remarks>
-       public class LocalTemporary : Expression, IMemoryLocation {
+       public class LocalTemporary : Expression, IMemoryLocation, IAssignMethod {
                LocalBuilder builder;
                bool is_address;
 
@@ -202,11 +206,23 @@ namespace Mono.CSharp {
                        builder = null;
                }
 
+               public override Expression CreateExpressionTree (EmitContext ec)
+               {
+                       ArrayList args = new ArrayList (1);
+                       args.Add (new Argument (this));
+                       return CreateExpressionFactoryCall ("Constant", args);
+               }
+
                public override Expression DoResolve (EmitContext ec)
                {
                        return this;
                }
 
+               public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
+               {
+                       return this;
+               }
+
                public override void Emit (EmitContext ec)
                {
                        ILGenerator ig = ec.ig;
@@ -220,6 +236,35 @@ namespace Mono.CSharp {
                                LoadFromPtr (ig, type);
                }
 
+               #region IAssignMethod Members
+
+               public void Emit (EmitContext ec, bool leave_copy)
+               {
+                       Emit (ec);
+
+                       if (leave_copy)
+                               Emit (ec);
+               }
+
+               public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
+               {
+                       if (prepare_for_load)
+                               throw new NotImplementedException ();
+
+                       source.Emit (ec);
+
+                       Store (ec);
+
+                       if (leave_copy)
+                               Emit (ec);
+               }
+
+               #endregion
+
+               public LocalBuilder Builder {
+                       get { return builder; }
+               }
+
                // NB: if you have `is_address' on the stack there must
                // be a managed pointer. Otherwise, it is the type from
                // the ctor.
@@ -247,6 +292,11 @@ namespace Mono.CSharp {
                                ig.Emit (OpCodes.Ldloca, builder);
                }
 
+               public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
+               {
+                       type = storey.MutateType (type);
+               }
+
                public bool PointsToAddress {
                        get {
                                return is_address;
@@ -259,155 +309,51 @@ namespace Mono.CSharp {
        ///   the expression represented by target.
        /// </summary>
        public class Assign : ExpressionStatement {
-               protected Expression target, source, real_source;
-               protected LocalTemporary temp = null, real_temp = null;
-               protected Assign embedded = null;
-               protected bool is_embedded = false;
-               protected bool must_free_temp = false;
-
-               public Assign (Expression target, Expression source)
-                       : this (target, source, target.Location)
-               {
-               }
+               protected Expression target, source;
 
-               public Assign (Expression target, Expression source, Location l)
+               protected Assign (Expression target, Expression source, Location loc)
                {
                        this.target = target;
-                       this.source = this.real_source = source;
-                       this.loc = l;
-               }
-
-               protected Assign (Assign embedded, Location l)
-                       : this (embedded.target, embedded.source, l)
-               {
-                       this.is_embedded = true;
+                       this.source = source;
+                       this.loc = loc;
                }
-
-               protected virtual Assign GetEmbeddedAssign (Location loc)
+               
+               public override Expression CreateExpressionTree (EmitContext ec)
                {
-                       return new Assign (this, loc);
+                       Report.Error (832, loc, "An expression tree cannot contain an assignment operator");
+                       return null;
                }
 
                public Expression Target {
-                       get {
-                               return target;
-                       }
-
-                       set {
-                               target = value;
-                       }
+                       get { return target; }
                }
 
                public Expression Source {
-                       get {
-                               return source;
-                       }
-
-                       set {
-                               source = value;
-                       }
-               }
-
-               public static void error70 (EventInfo ei, Location l)
-               {
-                       Report.Error (70, l, "The event `" + TypeManager.CSharpSignature (ei) +
-                                     "' can only appear on the left hand side of += or -= (except when" +
-                                     " used from within the type `" + ei.DeclaringType + "')");
+                       get { return source; }
                }
 
-               //
-               // Will return either `this' or an instance of `New'.
-               //
                public override Expression DoResolve (EmitContext ec)
                {
-                       // Create an embedded assignment if our source is an assignment.
-                       if (source is Assign)
-                               source = embedded = ((Assign) source).GetEmbeddedAssign (loc);
-
-                       real_source = source = source.Resolve (ec);
+                       bool ok = true;
+                       source = source.Resolve (ec);
+                                               
                        if (source == null) {
-                               // Ensure that we don't propagate the error as spurious "uninitialized variable" errors.
-                               target = target.ResolveLValue (ec, EmptyExpression.Null, Location);
-                               return null;
+                               ok = false;
+                               source = EmptyExpression.Null;
                        }
 
-                       //
-                       // This is used in an embedded assignment.
-                       // As an example, consider the statement "A = X = Y = Z".
-                       //
-                       if (is_embedded && !(source is Constant)) {
-                               // If this is the innermost assignment (the "Y = Z" in our example),
-                               // create a new temporary local, otherwise inherit that variable
-                               // from our child (the "X = (Y = Z)" inherits the local from the
-                               // "Y = Z" assignment).
-
-                               if (embedded == null) {
-                                       if (this is CompoundAssign)
-                                               real_temp = temp = new LocalTemporary (target.Type);
-                                       else
-                                               real_temp = temp = new LocalTemporary (source.Type);
-                               } else
-                                       temp = embedded.temp;
-
-                               // Set the source to the new temporary variable.
-                               // This means that the following target.ResolveLValue () will tell
-                               // the target to read it's source value from that variable.
-                               source = temp;
-                       }
-
-                       // If we have an embedded assignment, use the embedded assignment's temporary
-                       // local variable as source.
-                       if (embedded != null)
-                               source = (embedded.temp != null) ? embedded.temp : embedded.source;
-
                        target = target.ResolveLValue (ec, source, Location);
 
-                       if (target == null)
+                       if (target == null || !ok)
                                return null;
 
-                       bool same_assignment = (embedded != null) ? embedded.Target.Equals(target) : source.Equals (target);
-                       if (same_assignment) {
-                               Report.Warning (1717, 3, loc, "Assignment made to same variable; did you mean to assign something else?");
-                       }
-
                        Type target_type = target.Type;
-                       Type source_type = real_source.Type;
+                       Type source_type = source.Type;
 
-                       // If we're an embedded assignment, our parent will reuse our source as its
-                       // source, it won't read from our target.
-                       if (is_embedded)
-                               type = source_type;
-                       else
-                               type = target_type;
                        eclass = ExprClass.Value;
+                       type = target_type;
 
-                       if (target is EventExpr) {
-                               EventInfo ei = ((EventExpr) target).EventInfo;
-
-                               Expression ml = MemberLookup (
-                                       ec.ContainerType, ec.ContainerType, ei.Name,
-                                       MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
-
-                               if (ml == null) {
-                                       //
-                                       // If this is the case, then the Event does not belong
-                                       // to this Type and so, according to the spec
-                                       // is allowed to only appear on the left hand of
-                                       // the += and -= operators
-                                       //
-                                       // Note that target will not appear as an EventExpr
-                                       // in the case it is being referenced within the same type container;
-                                       // it will appear as a FieldExpr in that case.
-                                       //
-
-                                       if (!(source is BinaryDelegate)) {
-                                               error70 (ei, loc);
-                                               return null;
-                                       }
-                               }
-                       }
-
-                       if (!(target is IAssignMethod) && (target.eclass != ExprClass.EventAccess)) {
+                       if (!(target is IAssignMethod)) {
                                Error_ValueAssignment (loc);
                                return null;
                        }
@@ -419,178 +365,220 @@ namespace Mono.CSharp {
                                   (source is MethodGroupExpr)){
                                ((MethodGroupExpr) source).ReportUsageError ();
                                return null;
-
                        }
 
-                       if (target_type == source_type){
-                               if (source is New && target_type.IsValueType &&
-                                   (target.eclass != ExprClass.IndexerAccess) && (target.eclass != ExprClass.PropertyAccess)){
-                                       New n = (New) source;
-
-                                       if (n.SetValueTypeVariable (target))
-                                               return n;
-                                       else
-                                               return null;
-                               }
+                       if (!TypeManager.IsEqual (target_type, source_type)){
+                               Expression resolved = ResolveConversions (ec);
 
-                               return this;
+                               if (resolved != this)
+                                       return resolved;
                        }
 
-                       //
-                       // If this assignment/operator was part of a compound binary
-                       // operator, then we allow an explicit conversion, as detailed
-                       // in the spec.
-                       //
+                       return this;
+               }
 
-                       if (this is CompoundAssign){
-                               CompoundAssign a = (CompoundAssign) this;
+               public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
+               {
+                       source.MutateHoistedGenericType (storey);
+                       target.MutateHoistedGenericType (storey);
+                       type = storey.MutateType (type);                        
+               }
 
-                               Binary b = source as Binary;
-                               if (b != null){
-                                       //
-                                       // 1. if the source is explicitly convertible to the
-                                       //    target_type
-                                       //
+               protected virtual Expression ResolveConversions (EmitContext ec)
+               {
+                       source = Convert.ImplicitConversionRequired (ec, source, target.Type, loc);
+                       if (source == null)
+                               return null;
 
-                                       source = Convert.ExplicitConversion (ec, source, target_type, loc);
-                                       if (source == null){
-                                               a.original_source.Error_ValueCannotBeConverted (loc, target_type, true);
-                                               return null;
-                                       }
-
-                                       //
-                                       // 2. and the original right side is implicitly convertible to
-                                       // the type of target
-                                       //
-                                       if (Convert.ImplicitStandardConversionExists (a.original_source, target_type))
-                                               return this;
-
-                                       //
-                                       // In the spec 2.4 they added: or if type of the target is int
-                                       // and the operator is a shift operator...
-                                       //
-                                       if (source_type == TypeManager.int32_type &&
-                                           (b.Oper == Binary.Operator.LeftShift || b.Oper == Binary.Operator.RightShift))
-                                               return this;
-
-                                       a.original_source.Error_ValueCannotBeConverted (loc, target_type, false);
-                                       return null;
-                               }
-                       }
+                       return this;
+               }
 
-                       if (source.eclass == ExprClass.MethodGroup && !TypeManager.IsDelegateType (target_type)) {
-                               Report.Error (428, source.Location, "Cannot convert method group `{0}' to non-delegate type `{1}'. Did you intend to invoke the method?",
-                                       ((MethodGroupExpr)source).Name, target.GetSignatureForError ());
-                               return null;
-                       }
+               void Emit (EmitContext ec, bool is_statement)
+               {
+                       IAssignMethod t = (IAssignMethod) target;
+                       t.EmitAssign (ec, source, !is_statement, this is CompoundAssign);
+               }
 
-                       source = Convert.ImplicitConversionRequired (ec, source, target_type, loc);
-                       if (source == null)
-                               return null;
+               public override void Emit (EmitContext ec)
+               {
+                       Emit (ec, false);
+               }
 
-                       // If we're an embedded assignment, we need to create a new temporary variable
-                       // for the converted value.  Our parent will use this new variable as its source.
-                       // The same applies when we have an embedded assignment - in this case, we need
-                       // to convert our embedded assignment's temporary local variable to the correct
-                       // type and store it in a new temporary local.
-                       if (is_embedded || embedded != null) {
-                               type = target_type;
-                               temp = new LocalTemporary (type);
-                               must_free_temp = true;
-                       }
+               public override void EmitStatement (EmitContext ec)
+               {
+                       Emit (ec, true);
+               }
 
-                       return this;
+               protected override void CloneTo (CloneContext clonectx, Expression t)
+               {
+                       Assign _target = (Assign) t;
+
+                       _target.target = target.Clone (clonectx);
+                       _target.source = source.Clone (clonectx);
+               }
+       }
+
+       class SimpleAssign : Assign {
+               public SimpleAssign (Expression target, Expression source)
+                       : this (target, source, target.Location)
+               {
                }
 
-               Expression EmitEmbedded (EmitContext ec)
+               public SimpleAssign (Expression target, Expression source, Location loc)
+                       : base (target, source, loc)
                {
-                       // Emit an embedded assignment.
+               }
 
-                       if (real_temp != null) {
-                               // If we're the innermost assignment, `real_source' is the right-hand
-                               // expression which gets assigned to all the variables left of it.
-                               // Emit this expression and store its result in real_temp.
-                               real_source.Emit (ec);
-                               real_temp.Store (ec);
+               bool CheckEqualAssign (Expression t)
+               {
+                       if (source is Assign) {
+                               Assign a = (Assign) source;
+                               if (t.Equals (a.Target))
+                                       return true;
+                               return a is SimpleAssign && ((SimpleAssign) a).CheckEqualAssign (t);
                        }
+                       return t.Equals (source);
+               }
+
+               public override Expression DoResolve (EmitContext ec)
+               {
+                       Expression e = base.DoResolve (ec);
+                       if (e == null || e != this)
+                               return e;
 
-                       if (embedded != null)
-                               embedded.EmitEmbedded (ec);
+                       if (CheckEqualAssign (target))
+                               Report.Warning (1717, 3, loc, "Assignment made to same variable; did you mean to assign something else?");
 
-                       // This happens when we've done a type conversion, in this case source will be
-                       // the expression which does the type conversion from real_temp.
-                       // So emit it and store the result in temp; this is the var which will be read
-                       // by our parent.
-                       if (temp != real_temp) {
-                               source.Emit (ec);
-                               temp.Store (ec);
-                       }
+                       return this;
+               }
+       }
+
+       // This class implements fields and events class initializers
+       public class FieldInitializer : Assign
+       {
+               //
+               // Keep resolved value because field initializers have their own rules
+               //
+               ExpressionStatement resolved;
+               IResolveContext rc;
 
-                       Expression temp_source = (temp != null) ? temp : source;
-                       ((IAssignMethod) target).EmitAssign (ec, temp_source, false, false);
-                       return temp_source;
+               public FieldInitializer (FieldBuilder field, Expression expression, IResolveContext rc)
+                       : base (new FieldExpr (field, expression.Location), expression, expression.Location)
+               {
+                       this.rc = rc;
+                       if (!field.IsStatic)
+                               ((FieldExpr)target).InstanceExpression = CompilerGeneratedThis.Instance;
                }
 
-               void ReleaseEmbedded (EmitContext ec)
+               public override Expression DoResolve (EmitContext ec)
                {
-                       if (embedded != null)
-                               embedded.ReleaseEmbedded (ec);
+                       // Field initializer can be resolved (fail) many times
+                       if (source == null)
+                               return null;
+
+                       if (resolved == null) {
+                               //
+                               // Field initializers are tricky for partial classes. They have to
+                               // share same costructor (block) but they have they own resolve scope.
+                               //
+
+                               // TODO: Use ResolveContext only
+                               EmitContext f_ec = new EmitContext (rc, rc.DeclContainer, loc, null, TypeManager.void_type, 0, true);
+                               f_ec.IsStatic = ec.IsStatic;
+                               f_ec.CurrentBlock = ec.CurrentBlock;
+
+                               EmitContext.Flags flags = EmitContext.Flags.InFieldInitializer;
+                               if (ec.IsInUnsafeScope)
+                                       flags |= EmitContext.Flags.InUnsafe;
+
+                               f_ec.Set (flags);
 
-                       if (real_temp != null)
-                               real_temp.Release (ec);
+                               resolved = base.DoResolve (f_ec) as ExpressionStatement;
+                       }
 
-                       if (must_free_temp)
-                               temp.Release (ec);
+                       return resolved;
                }
 
-               void Emit (EmitContext ec, bool is_statement)
+               public override void EmitStatement (EmitContext ec)
                {
-                       if (target is EventExpr) {
-                               ((EventExpr) target).EmitAddOrRemove (ec, source);
+                       if (resolved == null)
                                return;
+                       
+                       if (resolved != this)
+                               resolved.EmitStatement (ec);
+                       else
+                               base.EmitStatement (ec);
+               }
+               
+               public bool IsComplexInitializer {
+                       get { return !(source is Constant); }
+               }
+
+               public bool IsDefaultInitializer {
+                       get {
+                               Constant c = source as Constant;
+                               if (c == null)
+                                       return false;
+                               
+                               FieldExpr fe = (FieldExpr)target;
+                               return c.IsDefaultInitializer (fe.Type);
                        }
+               }
+       }
 
-                       IAssignMethod am = (IAssignMethod) target;
+       class EventAddOrRemove : ExpressionStatement {
+               EventExpr target;
+               Binary.Operator op;
+               Expression source;
 
-                       Expression temp_source;
-                       if (embedded != null) {
-                               temp_source = embedded.EmitEmbedded (ec);
+               public EventAddOrRemove (Expression target, Binary.Operator op, Expression source, Location loc)
+               {
+                       this.target = target as EventExpr;
+                       this.op = op;
+                       this.source = source;
+                       this.loc = loc;
+               }
 
-                               if (temp != null) {
-                                       source.Emit (ec);
-                                       temp.Store (ec);
-                                       temp_source = temp;
-                               }
-                       } else
-                               temp_source = source;
+               public override Expression CreateExpressionTree (EmitContext ec)
+               {
+                       return new SimpleAssign (target, source).CreateExpressionTree (ec);
+               }
 
-                       am.EmitAssign (ec, temp_source, !is_statement, this is CompoundAssign);
+               public override Expression DoResolve (EmitContext ec)
+               {
+                       source = source.Resolve (ec);
+                       if (source == null)
+                               return null;
 
-                       if (embedded != null) {
-                               if (temp != null)
-                                       temp.Release (ec);
-                               embedded.ReleaseEmbedded (ec);
-                       }
+                       source = Convert.ImplicitConversionRequired (ec, source, target.Type, loc);
+                       if (source == null)
+                               return null;
+
+                       eclass = ExprClass.Value;
+                       type = TypeManager.void_type;
+                       return this;
                }
 
                public override void Emit (EmitContext ec)
                {
-                       Emit (ec, false);
+                       if (RootContext.EvalMode)
+                               EmitStatement (ec);
+                       else
+                               throw new InternalErrorException ("don't know what to emit");                           
                }
 
                public override void EmitStatement (EmitContext ec)
                {
-                       Emit (ec, true);
+                       target.EmitAddOrRemove (ec, op == Binary.Operator.Addition, source);
                }
        }
 
-
        //
        // This class is used for compound assignments.
        //
        class CompoundAssign : Assign {
                Binary.Operator op;
-               public Expression original_source;
+               Expression original_source;
 
                public CompoundAssign (Binary.Operator op, Expression target, Expression source)
                        : base (target, source, target.Location)
@@ -599,15 +587,33 @@ namespace Mono.CSharp {
                        this.op = op;
                }
 
-               protected CompoundAssign (CompoundAssign embedded, Location l)
-                       : this (embedded.op, embedded.target, embedded.source)
-               {
-                       this.is_embedded = true;
-               }
+               public sealed class TargetExpression : Expression {
+                       Expression child;
+                       public TargetExpression (Expression child)
+                       {
+                               this.child = child;
+                               this.loc = child.Location;
+                       }
 
-               protected override Assign GetEmbeddedAssign (Location loc)
-               {
-                       return new CompoundAssign (this, loc);
+                       public override Expression CreateExpressionTree (EmitContext ec)
+                       {
+                               throw new NotSupportedException ("ET");
+                       }
+
+                       public override Expression DoResolve (EmitContext ec)
+                       {
+                               child = child.Resolve (ec);
+                               if (child == null)
+                                       return null;
+                               type = child.Type;
+                               eclass = ExprClass.Value;
+                               return this;
+                       }
+
+                       public override void Emit (EmitContext ec)
+                       {
+                               child.Emit (ec);
+                       }
                }
 
                public override Expression DoResolve (EmitContext ec)
@@ -616,7 +622,10 @@ namespace Mono.CSharp {
                        if (original_source == null)
                                return null;
 
-                       target = target.Resolve (ec);
+                       using (ec.Set (EmitContext.Flags.InCompoundAssignment)) {
+                               target = target.Resolve (ec);
+                       }
+                       
                        if (target == null)
                                return null;
 
@@ -624,13 +633,59 @@ namespace Mono.CSharp {
                                Error_CannotAssign (((MethodGroupExpr)target).Name, target.ExprClassName);
                                return null;
                        }
+
+                       if (target is EventExpr)
+                               return new EventAddOrRemove (target, op, original_source, loc).DoResolve (ec);
+
                        //
                        // Only now we can decouple the original source/target
                        // into a tree, to guarantee that we do not have side
                        // effects.
                        //
-                       source = new Binary (op, target, original_source);
+                       source = new Binary (op, new TargetExpression (target), original_source, true);
                        return base.DoResolve (ec);
                }
+
+               protected override Expression ResolveConversions (EmitContext ec)
+               {
+                       Type target_type = target.Type;
+
+                       //
+                       // 1. the return type is implicitly convertible to the type of target
+                       //
+                       if (Convert.ImplicitConversionExists (ec, source, target_type)) {
+                               source = Convert.ImplicitConversion (ec, source, target_type, loc);
+                               return this;
+                       }
+
+                       //
+                       // Otherwise, if the selected operator is a predefined operator
+                       //
+                       Binary b = source as Binary;
+                       if (b != null) {
+                               //
+                               // 2a. the operator is a shift operator
+                               //
+                               // 2b. the return type is explicitly convertible to the type of x, and
+                               // y is implicitly convertible to the type of x
+                               //
+                               if ((b.Oper & Binary.Operator.ShiftMask) != 0 ||
+                                       Convert.ImplicitConversionExists (ec, original_source, target_type)) {
+                                       source = Convert.ExplicitConversion (ec, source, target_type, loc);
+                                       return this;
+                               }
+                       }
+
+                       original_source.Error_ValueCannotBeConverted (ec, loc, target_type, false);
+                       return null;
+               }
+
+               protected override void CloneTo (CloneContext clonectx, Expression t)
+               {
+                       CompoundAssign ctarget = (CompoundAssign) t;
+
+                       ctarget.original_source = ctarget.source = source.Clone (clonectx);
+                       ctarget.target = target.Clone (clonectx);
+               }
        }
 }