mcs/mcs/argument.cs

   1 //
   2 // argument.cs: Argument expressions
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximain.com)
   6 //   Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Dual licensed under the terms of the MIT X11 or GNU GPL
   9 // Copyright 2003-2011 Novell, Inc.
  10 // Copyright 2011 Xamarin Inc
  11 //
  12
  13 using System;
  14 using System.Collections.Generic;
  15
  16 #if STATIC
  17 using IKVM.Reflection.Emit;
  18 #else
  19 using System.Reflection.Emit;
  20 #endif
  21
  22 namespace Mono.CSharp
  23 {
  24         //
  25         // Argument expression used for invocation
  26         //
  27         public class Argument
  28         {
  29                 public enum AType : byte
  30                 {
  31                         None = 0,
  32                         Ref = 1,                        // ref modifier used
  33                         Out = 2,                        // out modifier used
  34                         Default = 3,            // argument created from default parameter value
  35                         DynamicTypeName = 4,    // System.Type argument for dynamic binding
  36                         ExtensionType = 5,      // Instance expression inserted as the first argument
  37
  38                         // Conditional instance expression inserted as the first argument
  39                         ExtensionTypeConditionalAccess = 5 | ConditionalAccessFlag,
  40
  41                         ConditionalAccessFlag = 1 << 7
  42                 }
  43
  44                 public readonly AType ArgType;
  45                 public Expression Expr;
  46
  47                 public Argument (Expression expr, AType type)
  48                 {
  49                         this.Expr = expr;
  50                         this.ArgType = type;
  51                 }
  52
  53                 public Argument (Expression expr)
  54                 {
  55                         this.Expr = expr;
  56                 }
  57
  58                 #region Properties
  59
  60                 public bool IsByRef {
  61                         get { return ArgType == AType.Ref || ArgType == AType.Out; }
  62                 }
  63
  64                 public bool IsDefaultArgument {
  65                         get { return ArgType == AType.Default; }
  66                 }
  67
  68                 public bool IsExtensionType {
  69                         get {
  70                                 return (ArgType & AType.ExtensionType) == AType.ExtensionType;
  71                         }
  72                 }
  73
  74                 public Parameter.Modifier Modifier {
  75                         get {
  76                                 switch (ArgType) {
  77                                 case AType.Out:
  78                                         return Parameter.Modifier.OUT;
  79
  80                                 case AType.Ref:
  81                                         return Parameter.Modifier.REF;
  82
  83                                 default:
  84                                         return Parameter.Modifier.NONE;
  85                                 }
  86                         }
  87                 }
  88
  89                 public TypeSpec Type {
  90                         get { return Expr.Type; }
  91                 }
  92
  93                 #endregion
  94
  95                 public Argument Clone (Expression expr)
  96                 {
  97                         Argument a = (Argument) MemberwiseClone ();
  98                         a.Expr = expr;
  99                         return a;
 100                 }
 101
 102                 public Argument Clone (CloneContext clonectx)
 103                 {
 104                         return Clone (Expr.Clone (clonectx));
 105                 }
 106
 107                 public virtual Expression CreateExpressionTree (ResolveContext ec)
 108                 {
 109                         if (ArgType == AType.Default)
 110                                 ec.Report.Error (854, Expr.Location, "An expression tree cannot contain an invocation which uses optional parameter");
 111
 112                         return Expr.CreateExpressionTree (ec);
 113                 }
 114
 115
 116                 public virtual void Emit (EmitContext ec)
 117                 {
 118                         if (!IsByRef) {
 119                                 if (ArgType == AType.ExtensionTypeConditionalAccess) {
 120                                         var ie = new InstanceEmitter (Expr, false);
 121                                         ie.Emit (ec, true);
 122                                 } else {
 123                                         Expr.Emit (ec);
 124                                 }
 125
 126                                 return;
 127                         }
 128
 129                         AddressOp mode = AddressOp.Store;
 130                         if (ArgType == AType.Ref)
 131                                 mode |= AddressOp.Load;
 132
 133                         IMemoryLocation ml = (IMemoryLocation) Expr;
 134                         ml.AddressOf (ec, mode);
 135                 }
 136
 137                 public Argument EmitToField (EmitContext ec, bool cloneResult)
 138                 {
 139                         var res = Expr.EmitToField (ec);
 140                         if (cloneResult && res != Expr)
 141                                 return new Argument (res, ArgType);
 142
 143                         Expr = res;
 144                         return this;
 145                 }
 146
 147                 public void FlowAnalysis (FlowAnalysisContext fc)
 148                 {
 149                         if (ArgType == AType.Out) {
 150                                 var vr = Expr as VariableReference;
 151                                 if (vr != null) {
 152                                         if (vr.VariableInfo != null)
 153                                                 fc.SetVariableAssigned (vr.VariableInfo);
 154
 155                                         return;
 156                                 }
 157
 158                                 var fe = Expr as FieldExpr;
 159                                 if (fe != null) {
 160                                         fe.SetFieldAssigned (fc);
 161                                         return;
 162                                 }
 163
 164                                 return;
 165                         }
 166
 167                         Expr.FlowAnalysis (fc);
 168                 }
 169
 170                 public string GetSignatureForError ()
 171                 {
 172                         if (Expr.eclass == ExprClass.MethodGroup)
 173                                 return Expr.ExprClassName;
 174
 175                         return Expr.Type.GetSignatureForError ();
 176                 }
 177
 178                 public bool ResolveMethodGroup (ResolveContext ec)
 179                 {
 180                         SimpleName sn = Expr as SimpleName;
 181                         if (sn != null)
 182                                 Expr = sn.GetMethodGroup ();
 183
 184                         // FIXME: csc doesn't report any error if you try to use `ref' or
 185                         //        `out' in a delegate creation expression.
 186                         Expr = Expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 187                         if (Expr == null)
 188                                 return false;
 189
 190                         return true;
 191                 }
 192
 193                 public void Resolve (ResolveContext ec)
 194                 {
 195                         // Verify that the argument is readable
 196                         if (ArgType != AType.Out)
 197                                 Expr = Expr.Resolve (ec);
 198
 199                         // Verify that the argument is writeable
 200                         if (Expr != null && IsByRef)
 201                                 Expr = Expr.ResolveLValue (ec, EmptyExpression.OutAccess);
 202
 203                         if (Expr == null)
 204                                 Expr = ErrorExpression.Instance;
 205                 }
 206         }
 207
 208         public class MovableArgument : Argument
 209         {
 210                 LocalTemporary variable;
 211
 212                 public MovableArgument (Argument arg)
 213                         : this (arg.Expr, arg.ArgType)
 214                 {
 215                 }
 216
 217                 protected MovableArgument (Expression expr, AType modifier)
 218                         : base (expr, modifier)
 219                 {
 220                 }
 221
 222                 public override void Emit (EmitContext ec)
 223                 {
 224                         // TODO: Should guard against multiple emits
 225                         base.Emit (ec);
 226
 227                         // Release temporary variable when used
 228                         if (variable != null)
 229                                 variable.Release (ec);
 230                 }
 231
 232                 public void EmitToVariable (EmitContext ec)
 233                 {
 234                         var type = Expr.Type;
 235                         if (IsByRef) {
 236                                 var ml = (IMemoryLocation) Expr;
 237                                 ml.AddressOf (ec, AddressOp.LoadStore);
 238                                 type = ReferenceContainer.MakeType (ec.Module, type);
 239                         } else {
 240                                 Expr.Emit (ec);
 241                         }
 242
 243                         variable = new LocalTemporary (type);
 244                         variable.Store (ec);
 245
 246                         Expr = variable;
 247                 }
 248         }
 249
 250         public class NamedArgument : MovableArgument
 251         {
 252                 public readonly string Name;
 253                 readonly Location loc;
 254
 255                 public NamedArgument (string name, Location loc, Expression expr)
 256                         : this (name, loc, expr, AType.None)
 257                 {
 258                 }
 259
 260                 public NamedArgument (string name, Location loc, Expression expr, AType modifier)
 261                         : base (expr, modifier)
 262                 {
 263                         this.Name = name;
 264                         this.loc = loc;
 265                 }
 266
 267                 public override Expression CreateExpressionTree (ResolveContext ec)
 268                 {
 269                         ec.Report.Error (853, loc, "An expression tree cannot contain named argument");
 270                         return base.CreateExpressionTree (ec);
 271                 }
 272
 273                 public Location Location {
 274                         get { return loc; }
 275                 }
 276         }
 277
 278         public class Arguments
 279         {
 280                 sealed class ArgumentsOrdered : Arguments
 281                 {
 282                         readonly List<MovableArgument> ordered;
 283
 284                         public ArgumentsOrdered (Arguments args)
 285                                 : base (args.Count)
 286                         {
 287                                 AddRange (args);
 288                                 ordered = new List<MovableArgument> ();
 289                         }
 290
 291                         public void AddOrdered (MovableArgument arg)
 292                         {
 293                                 ordered.Add (arg);
 294                         }
 295
 296                         public override void FlowAnalysis (FlowAnalysisContext fc, List<MovableArgument> movable = null)
 297                         {
 298                                 foreach (var arg in ordered) {
 299                                         if (arg.ArgType != Argument.AType.Out)
 300                                                 arg.FlowAnalysis (fc);
 301                                 }
 302
 303                                 base.FlowAnalysis (fc, ordered);
 304                         }
 305
 306                         public override Arguments Emit (EmitContext ec, bool dup_args, bool prepareAwait)
 307                         {
 308                                 foreach (var a in ordered) {
 309                                         if (prepareAwait)
 310                                                 a.EmitToField (ec, false);
 311                                         else
 312                                                 a.EmitToVariable (ec);
 313                                 }
 314
 315                                 return base.Emit (ec, dup_args, prepareAwait);
 316                         }
 317                 }
 318
 319                 // Try not to add any more instances to this class, it's allocated a lot
 320                 List<Argument> args;
 321
 322                 public Arguments (int capacity)
 323                 {
 324                         args = new List<Argument> (capacity);
 325                 }
 326
 327                 private Arguments (List<Argument> args)
 328                 {
 329                         this.args = args;
 330                 }
 331
 332                 public void Add (Argument arg)
 333                 {
 334                         args.Add (arg);
 335                 }
 336
 337                 public void AddRange (Arguments args)
 338                 {
 339                         this.args.AddRange (args.args);
 340                 }
 341
 342                 public bool ContainsEmitWithAwait ()
 343                 {
 344                         foreach (var arg in args) {
 345                                 if (arg.Expr.ContainsEmitWithAwait ())
 346                                         return true;
 347                         }
 348
 349                         return false;
 350                 }
 351
 352                 public ArrayInitializer CreateDynamicBinderArguments (ResolveContext rc)
 353                 {
 354                         Location loc = Location.Null;
 355                         var all = new ArrayInitializer (args.Count, loc);
 356
 357                         MemberAccess binder = DynamicExpressionStatement.GetBinderNamespace (loc);
 358
 359                         foreach (Argument a in args) {
 360                                 Arguments dargs = new Arguments (2);
 361
 362                                 // CSharpArgumentInfoFlags.None = 0
 363                                 const string info_flags_enum = "CSharpArgumentInfoFlags";
 364                                 Expression info_flags = new IntLiteral (rc.BuiltinTypes, 0, loc);
 365
 366                                 if (a.Expr is Constant) {
 367                                         info_flags = new Binary (Binary.Operator.BitwiseOr, info_flags,
 368                                                 new MemberAccess (new MemberAccess (binder, info_flags_enum, loc), "Constant", loc));
 369                                 } else if (a.ArgType == Argument.AType.Ref) {
 370                                         info_flags = new Binary (Binary.Operator.BitwiseOr, info_flags,
 371                                                 new MemberAccess (new MemberAccess (binder, info_flags_enum, loc), "IsRef", loc));
 372                                         info_flags = new Binary (Binary.Operator.BitwiseOr, info_flags,
 373                                                 new MemberAccess (new MemberAccess (binder, info_flags_enum, loc), "UseCompileTimeType", loc));
 374                                 } else if (a.ArgType == Argument.AType.Out) {
 375                                         info_flags = new Binary (Binary.Operator.BitwiseOr, info_flags,
 376                                                 new MemberAccess (new MemberAccess (binder, info_flags_enum, loc), "IsOut", loc));
 377                                         info_flags = new Binary (Binary.Operator.BitwiseOr, info_flags,
 378                                                 new MemberAccess (new MemberAccess (binder, info_flags_enum, loc), "UseCompileTimeType", loc));
 379                                 } else if (a.ArgType == Argument.AType.DynamicTypeName) {
 380                                         info_flags = new Binary (Binary.Operator.BitwiseOr, info_flags,
 381                                                 new MemberAccess (new MemberAccess (binder, info_flags_enum, loc), "IsStaticType", loc));
 382                                 }
 383
 384                                 var arg_type = a.Expr.Type;
 385
 386                                 if (arg_type.BuiltinType != BuiltinTypeSpec.Type.Dynamic && arg_type != InternalType.NullLiteral) {
 387                                         MethodGroupExpr mg = a.Expr as MethodGroupExpr;
 388                                         if (mg != null) {
 389                                                 rc.Report.Error (1976, a.Expr.Location,
 390                                                         "The method group `{0}' cannot be used as an argument of dynamic operation. Consider using parentheses to invoke the method",
 391                                                         mg.Name);
 392                                         } else if (arg_type == InternalType.AnonymousMethod) {
 393                                                 rc.Report.Error (1977, a.Expr.Location,
 394                                                         "An anonymous method or lambda expression cannot be used as an argument of dynamic operation. Consider using a cast");
 395                                         } else if (arg_type.Kind == MemberKind.Void || arg_type == InternalType.Arglist || arg_type.IsPointer) {
 396                                                 rc.Report.Error (1978, a.Expr.Location,
 397                                                         "An expression of type `{0}' cannot be used as an argument of dynamic operation",
 398                                                         arg_type.GetSignatureForError ());
 399                                         }
 400
 401                                         info_flags = new Binary (Binary.Operator.BitwiseOr, info_flags,
 402                                                 new MemberAccess (new MemberAccess (binder, info_flags_enum, loc), "UseCompileTimeType", loc));
 403                                 }
 404
 405                                 string named_value;
 406                                 NamedArgument na = a as NamedArgument;
 407                                 if (na != null) {
 408                                         info_flags = new Binary (Binary.Operator.BitwiseOr, info_flags,
 409                                                 new MemberAccess (new MemberAccess (binder, info_flags_enum, loc), "NamedArgument", loc));
 410
 411                                         named_value = na.Name;
 412                                 } else {
 413                                         named_value = null;
 414                                 }
 415
 416                                 dargs.Add (new Argument (info_flags));
 417                                 dargs.Add (new Argument (new StringLiteral (rc.BuiltinTypes, named_value, loc)));
 418                                 all.Add (new Invocation (new MemberAccess (new MemberAccess (binder, "CSharpArgumentInfo", loc), "Create", loc), dargs));
 419                         }
 420
 421                         return all;
 422                 }
 423
 424                 public static Arguments CreateForExpressionTree (ResolveContext ec, Arguments args, params Expression[] e)
 425                 {
 426                         Arguments all = new Arguments ((args == null ? 0 : args.Count) + e.Length);
 427                         for (int i = 0; i < e.Length; ++i) {
 428                                 if (e [i] != null)
 429                                         all.Add (new Argument (e[i]));
 430                         }
 431
 432                         if (args != null) {
 433                                 foreach (Argument a in args.args) {
 434                                         Expression tree_arg = a.CreateExpressionTree (ec);
 435                                         if (tree_arg != null)
 436                                                 all.Add (new Argument (tree_arg));
 437                                 }
 438                         }
 439
 440                         return all;
 441                 }
 442
 443                 public void CheckArrayAsAttribute (CompilerContext ctx)
 444                 {
 445                         foreach (Argument arg in args) {
 446                                 // Type is undefined (was error 246)
 447                                 if (arg.Type == null)
 448                                         continue;
 449
 450                                 if (arg.Type.IsArray)
 451                                         ctx.Report.Warning (3016, 1, arg.Expr.Location, "Arrays as attribute arguments are not CLS-compliant");
 452                         }
 453                 }
 454
 455                 public Arguments Clone (CloneContext ctx)
 456                 {
 457                         Arguments cloned = new Arguments (args.Count);
 458                         foreach (Argument a in args)
 459                                 cloned.Add (a.Clone (ctx));
 460
 461                         return cloned;
 462                 }
 463
 464                 public int Count {
 465                         get { return args.Count; }
 466                 }
 467
 468                 //
 469                 // Emits a list of resolved Arguments
 470                 //
 471                 public void Emit (EmitContext ec)
 472                 {
 473                         Emit (ec, false, false);
 474                 }
 475
 476                 public void EmitPrepare (EmitContext ec)
 477                 {
 478                         foreach (var a in args) {
 479                                 a.Expr.EmitPrepare (ec);
 480                         }
 481                 }
 482
 483                 //
 484                 // if `dup_args' is true or any of arguments contains await.
 485                 // A copy of all arguments will be returned to the caller
 486                 //
 487                 public virtual Arguments Emit (EmitContext ec, bool dup_args, bool prepareAwait)
 488                 {
 489                         List<Argument> dups;
 490
 491                         if ((dup_args && Count != 0) || prepareAwait)
 492                                 dups = new List<Argument> (Count);
 493                         else
 494                                 dups = null;
 495
 496                         LocalTemporary lt;
 497                         foreach (Argument a in args) {
 498                                 if (prepareAwait) {
 499                                         dups.Add (a.EmitToField (ec, true));
 500                                         continue;
 501                                 }
 502
 503                                 a.Emit (ec);
 504
 505                                 if (!dup_args) {
 506                                         continue;
 507                                 }
 508
 509                                 if (a.Expr.IsSideEffectFree) {
 510                                         //
 511                                         // No need to create a temporary variable for side effect free expressions. I assume
 512                                         // all side-effect free expressions are cheap, this has to be tweaked when we become
 513                                         // more aggressive on detection
 514                                         //
 515                                         dups.Add (a);
 516                                 } else {
 517                                         ec.Emit (OpCodes.Dup);
 518
 519                                         // TODO: Release local temporary on next Emit
 520                                         // Need to add a flag to argument to indicate this
 521                                         lt = new LocalTemporary (a.Type);
 522                                         lt.Store (ec);
 523
 524                                         dups.Add (new Argument (lt, a.ArgType));
 525                                 }
 526                         }
 527
 528                         if (dups != null)
 529                                 return new Arguments (dups);
 530
 531                         return null;
 532                 }
 533
 534                 public virtual void FlowAnalysis (FlowAnalysisContext fc, List<MovableArgument> movable = null)
 535                 {
 536                         bool has_out = false;
 537                         foreach (var arg in args) {
 538                                 if (arg.ArgType == Argument.AType.Out) {
 539                                         has_out = true;
 540                                         continue;
 541                                 }
 542
 543                                 if (movable == null) {
 544                                         arg.FlowAnalysis (fc);
 545                                         continue;
 546                                 }
 547
 548                                 var ma = arg as MovableArgument;
 549                                 if (ma != null && !movable.Contains (ma))
 550                                         arg.FlowAnalysis (fc);
 551                         }
 552
 553                         if (!has_out)
 554                                 return;
 555
 556                         foreach (var arg in args) {
 557                                 if (arg.ArgType != Argument.AType.Out)
 558                                         continue;
 559
 560                                 arg.FlowAnalysis (fc);
 561                         }
 562                 }
 563
 564                 public List<Argument>.Enumerator GetEnumerator ()
 565                 {
 566                         return args.GetEnumerator ();
 567                 }
 568
 569                 //
 570                 // At least one argument is of dynamic type
 571                 //
 572                 public bool HasDynamic {
 573                         get {
 574                                 foreach (Argument a in args) {
 575                                         if (a.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic && !a.IsByRef)
 576                                                 return true;
 577                                 }
 578
 579                                 return false;
 580                         }
 581                 }
 582
 583                 //
 584                 // At least one argument is named argument
 585                 //
 586                 public bool HasNamed {
 587                         get {
 588                                 foreach (Argument a in args) {
 589                                         if (a is NamedArgument)
 590                                                 return true;
 591                                 }
 592
 593                                 return false;
 594                         }
 595                 }
 596
 597
 598                 public void Insert (int index, Argument arg)
 599                 {
 600                         args.Insert (index, arg);
 601                 }
 602
 603                 public static System.Linq.Expressions.Expression[] MakeExpression (Arguments args, BuilderContext ctx)
 604                 {
 605                         if (args == null || args.Count == 0)
 606                                 return null;
 607
 608                         var exprs = new System.Linq.Expressions.Expression [args.Count];
 609                         for (int i = 0; i < exprs.Length; ++i) {
 610                                 Argument a = args.args [i];
 611                                 exprs[i] = a.Expr.MakeExpression (ctx);
 612                         }
 613
 614                         return exprs;
 615                 }
 616
 617                 //
 618                 // For named arguments when the order of execution is different
 619                 // to order of invocation
 620                 //
 621                 public Arguments MarkOrderedArgument (NamedArgument a)
 622                 {
 623                         //
 624                         // An expression has no effect on left-to-right execution
 625                         //
 626                         if (a.Expr.IsSideEffectFree)
 627                                 return this;
 628
 629                         ArgumentsOrdered ra = this as ArgumentsOrdered;
 630                         if (ra == null) {
 631                                 ra = new ArgumentsOrdered (this);
 632
 633                                 for (int i = 0; i < args.Count; ++i) {
 634                                         var la = args [i];
 635                                         if (la == a)
 636                                                 break;
 637
 638                                         //
 639                                         // When the argument is filled later by default expression
 640                                         //
 641                                         if (la == null)
 642                                                 continue;
 643
 644                                         var ma = la as MovableArgument;
 645                                         if (ma == null) {
 646                                                 ma = new MovableArgument (la);
 647                                                 ra.args[i] = ma;
 648                                         }
 649
 650                                         ra.AddOrdered (ma);
 651                                 }
 652                         }
 653
 654                         ra.AddOrdered (a);
 655                         return ra;
 656                 }
 657
 658                 //
 659                 // Returns dynamic when at least one argument is of dynamic type
 660                 //
 661                 public void Resolve (ResolveContext rc, out bool dynamic)
 662                 {
 663                         dynamic = false;
 664
 665                         List<LocalVariable> var_locals = null;
 666                         foreach (Argument a in args) {
 667                                 a.Resolve (rc);
 668
 669                                 if (a.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic && !a.IsByRef) {
 670                                         dynamic = true;
 671                                         continue;
 672                                 }
 673
 674                                 if (a.Type == InternalType.VarOutType) {
 675                                         var de = a.Expr as DeclarationExpression;
 676                                         if (de != null) {
 677                                                 if (var_locals == null)
 678                                                         var_locals = new List<LocalVariable> ();
 679
 680                                                 var_locals.Add (de.Variable);
 681                                                 continue;
 682                                         }
 683
 684                                         var lvr = a.Expr as LocalVariableReference;
 685                                         if (lvr != null && var_locals != null && var_locals.Contains (lvr.local_info)) {
 686                                                 rc.Report.Error (8196, lvr.Location, "Reference to an implicitly typed out variable `{0}' is not permitted in the same argument list", lvr.Name);
 687                                                 lvr.Type = InternalType.ErrorType;
 688                                         }
 689                                 }
 690                         }
 691                 }
 692
 693                 public void RemoveAt (int index)
 694                 {
 695                         args.RemoveAt (index);
 696                 }
 697
 698                 public Argument this [int index] {
 699                         get { return args [index]; }
 700                         set { args [index] = value; }
 701                 }
 702         }
 703 }