contrib/llvm/tools/clang/lib/Sema/SemaPseudoObject.cpp

   1 //===--- SemaPseudoObject.cpp - Semantic Analysis for Pseudo-Objects ------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 //  This file implements semantic analysis for expressions involving
  11 //  pseudo-object references.  Pseudo-objects are conceptual objects
  12 //  whose storage is entirely abstract and all accesses to which are
  13 //  translated through some sort of abstraction barrier.
  14 //
  15 //  For example, Objective-C objects can have "properties", either
  16 //  declared or undeclared.  A property may be accessed by writing
  17 //    expr.prop
  18 //  where 'expr' is an r-value of Objective-C pointer type and 'prop'
  19 //  is the name of the property.  If this expression is used in a context
  20 //  needing an r-value, it is treated as if it were a message-send
  21 //  of the associated 'getter' selector, typically:
  22 //    [expr prop]
  23 //  If it is used as the LHS of a simple assignment, it is treated
  24 //  as a message-send of the associated 'setter' selector, typically:
  25 //    [expr setProp: RHS]
  26 //  If it is used as the LHS of a compound assignment, or the operand
  27 //  of a unary increment or decrement, both are required;  for example,
  28 //  'expr.prop *= 100' would be translated to:
  29 //    [expr setProp: [expr prop] * 100]
  30 //
  31 //===----------------------------------------------------------------------===//
  32
  33 #include "clang/Sema/SemaInternal.h"
  34 #include "clang/AST/ExprObjC.h"
  35 #include "clang/Basic/CharInfo.h"
  36 #include "clang/Lex/Preprocessor.h"
  37 #include "clang/Sema/Initialization.h"
  38 #include "clang/Sema/ScopeInfo.h"
  39 #include "llvm/ADT/SmallString.h"
  40
  41 using namespace clang;
  42 using namespace sema;
  43
  44 namespace {
  45   // Basically just a very focused copy of TreeTransform.
  46   template <class T> struct Rebuilder {
  47     Sema &S;
  48     Rebuilder(Sema &S) : S(S) {}
  49
  50     T &getDerived() { return static_cast<T&>(*this); }
  51
  52     Expr *rebuild(Expr *e) {
  53       // Fast path: nothing to look through.
  54       if (typename T::specific_type *specific
  55             = dyn_cast<typename T::specific_type>(e))
  56         return getDerived().rebuildSpecific(specific);
  57
  58       // Otherwise, we should look through and rebuild anything that
  59       // IgnoreParens would.
  60
  61       if (ParenExpr *parens = dyn_cast<ParenExpr>(e)) {
  62         e = rebuild(parens->getSubExpr());
  63         return new (S.Context) ParenExpr(parens->getLParen(),
  64                                          parens->getRParen(),
  65                                          e);
  66       }
  67
  68       if (UnaryOperator *uop = dyn_cast<UnaryOperator>(e)) {
  69         assert(uop->getOpcode() == UO_Extension);
  70         e = rebuild(uop->getSubExpr());
  71         return new (S.Context) UnaryOperator(e, uop->getOpcode(),
  72                                              uop->getType(),
  73                                              uop->getValueKind(),
  74                                              uop->getObjectKind(),
  75                                              uop->getOperatorLoc());
  76       }
  77
  78       if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
  79         assert(!gse->isResultDependent());
  80         unsigned resultIndex = gse->getResultIndex();
  81         unsigned numAssocs = gse->getNumAssocs();
  82
  83         SmallVector<Expr*, 8> assocs(numAssocs);
  84         SmallVector<TypeSourceInfo*, 8> assocTypes(numAssocs);
  85
  86         for (unsigned i = 0; i != numAssocs; ++i) {
  87           Expr *assoc = gse->getAssocExpr(i);
  88           if (i == resultIndex) assoc = rebuild(assoc);
  89           assocs[i] = assoc;
  90           assocTypes[i] = gse->getAssocTypeSourceInfo(i);
  91         }
  92
  93         return new (S.Context) GenericSelectionExpr(S.Context,
  94                                                     gse->getGenericLoc(),
  95                                                     gse->getControllingExpr(),
  96                                                     assocTypes,
  97                                                     assocs,
  98                                                     gse->getDefaultLoc(),
  99                                                     gse->getRParenLoc(),
 100                                       gse->containsUnexpandedParameterPack(),
 101                                                     resultIndex);
 102       }
 103
 104       if (ChooseExpr *ce = dyn_cast<ChooseExpr>(e)) {
 105         assert(!ce->isConditionDependent());
 106
 107         Expr *LHS = ce->getLHS(), *RHS = ce->getRHS();
 108         Expr *&rebuiltExpr = ce->isConditionTrue() ? LHS : RHS;
 109         rebuiltExpr = rebuild(rebuiltExpr);
 110
 111         return new (S.Context) ChooseExpr(ce->getBuiltinLoc(),
 112                                           ce->getCond(),
 113                                           LHS, RHS,
 114                                           rebuiltExpr->getType(),
 115                                           rebuiltExpr->getValueKind(),
 116                                           rebuiltExpr->getObjectKind(),
 117                                           ce->getRParenLoc(),
 118                                           ce->isConditionTrue(),
 119                                           rebuiltExpr->isTypeDependent(),
 120                                           rebuiltExpr->isValueDependent());
 121       }
 122
 123       llvm_unreachable("bad expression to rebuild!");
 124     }
 125   };
 126
 127   struct ObjCPropertyRefRebuilder : Rebuilder<ObjCPropertyRefRebuilder> {
 128     Expr *NewBase;
 129     ObjCPropertyRefRebuilder(Sema &S, Expr *newBase)
 130       : Rebuilder<ObjCPropertyRefRebuilder>(S), NewBase(newBase) {}
 131
 132     typedef ObjCPropertyRefExpr specific_type;
 133     Expr *rebuildSpecific(ObjCPropertyRefExpr *refExpr) {
 134       // Fortunately, the constraint that we're rebuilding something
 135       // with a base limits the number of cases here.
 136       assert(refExpr->isObjectReceiver());
 137
 138       if (refExpr->isExplicitProperty()) {
 139         return new (S.Context)
 140           ObjCPropertyRefExpr(refExpr->getExplicitProperty(),
 141                               refExpr->getType(), refExpr->getValueKind(),
 142                               refExpr->getObjectKind(), refExpr->getLocation(),
 143                               NewBase);
 144       }
 145       return new (S.Context)
 146         ObjCPropertyRefExpr(refExpr->getImplicitPropertyGetter(),
 147                             refExpr->getImplicitPropertySetter(),
 148                             refExpr->getType(), refExpr->getValueKind(),
 149                             refExpr->getObjectKind(),refExpr->getLocation(),
 150                             NewBase);
 151     }
 152   };
 153
 154   struct ObjCSubscriptRefRebuilder : Rebuilder<ObjCSubscriptRefRebuilder> {
 155     Expr *NewBase;
 156     Expr *NewKeyExpr;
 157     ObjCSubscriptRefRebuilder(Sema &S, Expr *newBase, Expr *newKeyExpr)
 158     : Rebuilder<ObjCSubscriptRefRebuilder>(S),
 159       NewBase(newBase), NewKeyExpr(newKeyExpr) {}
 160
 161     typedef ObjCSubscriptRefExpr specific_type;
 162     Expr *rebuildSpecific(ObjCSubscriptRefExpr *refExpr) {
 163       assert(refExpr->getBaseExpr());
 164       assert(refExpr->getKeyExpr());
 165
 166       return new (S.Context)
 167         ObjCSubscriptRefExpr(NewBase,
 168                              NewKeyExpr,
 169                              refExpr->getType(), refExpr->getValueKind(),
 170                              refExpr->getObjectKind(),refExpr->getAtIndexMethodDecl(),
 171                              refExpr->setAtIndexMethodDecl(),
 172                              refExpr->getRBracket());
 173     }
 174   };
 175
 176   struct MSPropertyRefRebuilder : Rebuilder<MSPropertyRefRebuilder> {
 177     Expr *NewBase;
 178     MSPropertyRefRebuilder(Sema &S, Expr *newBase)
 179     : Rebuilder<MSPropertyRefRebuilder>(S), NewBase(newBase) {}
 180
 181     typedef MSPropertyRefExpr specific_type;
 182     Expr *rebuildSpecific(MSPropertyRefExpr *refExpr) {
 183       assert(refExpr->getBaseExpr());
 184
 185       return new (S.Context)
 186         MSPropertyRefExpr(NewBase, refExpr->getPropertyDecl(),
 187                        refExpr->isArrow(), refExpr->getType(),
 188                        refExpr->getValueKind(), refExpr->getQualifierLoc(),
 189                        refExpr->getMemberLoc());
 190     }
 191   };
 192
 193   class PseudoOpBuilder {
 194   public:
 195     Sema &S;
 196     unsigned ResultIndex;
 197     SourceLocation GenericLoc;
 198     SmallVector<Expr *, 4> Semantics;
 199
 200     PseudoOpBuilder(Sema &S, SourceLocation genericLoc)
 201       : S(S), ResultIndex(PseudoObjectExpr::NoResult),
 202         GenericLoc(genericLoc) {}
 203
 204     virtual ~PseudoOpBuilder() {}
 205
 206     /// Add a normal semantic expression.
 207     void addSemanticExpr(Expr *semantic) {
 208       Semantics.push_back(semantic);
 209     }
 210
 211     /// Add the 'result' semantic expression.
 212     void addResultSemanticExpr(Expr *resultExpr) {
 213       assert(ResultIndex == PseudoObjectExpr::NoResult);
 214       ResultIndex = Semantics.size();
 215       Semantics.push_back(resultExpr);
 216     }
 217
 218     ExprResult buildRValueOperation(Expr *op);
 219     ExprResult buildAssignmentOperation(Scope *Sc,
 220                                         SourceLocation opLoc,
 221                                         BinaryOperatorKind opcode,
 222                                         Expr *LHS, Expr *RHS);
 223     ExprResult buildIncDecOperation(Scope *Sc, SourceLocation opLoc,
 224                                     UnaryOperatorKind opcode,
 225                                     Expr *op);
 226
 227     virtual ExprResult complete(Expr *syntacticForm);
 228
 229     OpaqueValueExpr *capture(Expr *op);
 230     OpaqueValueExpr *captureValueAsResult(Expr *op);
 231
 232     void setResultToLastSemantic() {
 233       assert(ResultIndex == PseudoObjectExpr::NoResult);
 234       ResultIndex = Semantics.size() - 1;
 235     }
 236
 237     /// Return true if assignments have a non-void result.
 238     bool CanCaptureValueOfType(QualType ty) {
 239       assert(!ty->isIncompleteType());
 240       assert(!ty->isDependentType());
 241
 242       if (const CXXRecordDecl *ClassDecl = ty->getAsCXXRecordDecl())
 243         return ClassDecl->isTriviallyCopyable();
 244       return true;
 245     }
 246
 247     virtual Expr *rebuildAndCaptureObject(Expr *) = 0;
 248     virtual ExprResult buildGet() = 0;
 249     virtual ExprResult buildSet(Expr *, SourceLocation,
 250                                 bool captureSetValueAsResult) = 0;
 251   };
 252
 253   /// A PseudoOpBuilder for Objective-C \@properties.
 254   class ObjCPropertyOpBuilder : public PseudoOpBuilder {
 255     ObjCPropertyRefExpr *RefExpr;
 256     ObjCPropertyRefExpr *SyntacticRefExpr;
 257     OpaqueValueExpr *InstanceReceiver;
 258     ObjCMethodDecl *Getter;
 259
 260     ObjCMethodDecl *Setter;
 261     Selector SetterSelector;
 262     Selector GetterSelector;
 263
 264   public:
 265     ObjCPropertyOpBuilder(Sema &S, ObjCPropertyRefExpr *refExpr) :
 266       PseudoOpBuilder(S, refExpr->getLocation()), RefExpr(refExpr),
 267       SyntacticRefExpr(0), InstanceReceiver(0), Getter(0), Setter(0) {
 268     }
 269
 270     ExprResult buildRValueOperation(Expr *op);
 271     ExprResult buildAssignmentOperation(Scope *Sc,
 272                                         SourceLocation opLoc,
 273                                         BinaryOperatorKind opcode,
 274                                         Expr *LHS, Expr *RHS);
 275     ExprResult buildIncDecOperation(Scope *Sc, SourceLocation opLoc,
 276                                     UnaryOperatorKind opcode,
 277                                     Expr *op);
 278
 279     bool tryBuildGetOfReference(Expr *op, ExprResult &result);
 280     bool findSetter(bool warn=true);
 281     bool findGetter();
 282
 283     Expr *rebuildAndCaptureObject(Expr *syntacticBase);
 284     ExprResult buildGet();
 285     ExprResult buildSet(Expr *op, SourceLocation, bool);
 286     ExprResult complete(Expr *SyntacticForm);
 287
 288     bool isWeakProperty() const;
 289   };
 290
 291  /// A PseudoOpBuilder for Objective-C array/dictionary indexing.
 292  class ObjCSubscriptOpBuilder : public PseudoOpBuilder {
 293    ObjCSubscriptRefExpr *RefExpr;
 294    OpaqueValueExpr *InstanceBase;
 295    OpaqueValueExpr *InstanceKey;
 296    ObjCMethodDecl *AtIndexGetter;
 297    Selector AtIndexGetterSelector;
 298
 299    ObjCMethodDecl *AtIndexSetter;
 300    Selector AtIndexSetterSelector;
 301
 302  public:
 303     ObjCSubscriptOpBuilder(Sema &S, ObjCSubscriptRefExpr *refExpr) :
 304       PseudoOpBuilder(S, refExpr->getSourceRange().getBegin()),
 305       RefExpr(refExpr),
 306     InstanceBase(0), InstanceKey(0),
 307     AtIndexGetter(0), AtIndexSetter(0) { }
 308
 309    ExprResult buildRValueOperation(Expr *op);
 310    ExprResult buildAssignmentOperation(Scope *Sc,
 311                                        SourceLocation opLoc,
 312                                        BinaryOperatorKind opcode,
 313                                        Expr *LHS, Expr *RHS);
 314    Expr *rebuildAndCaptureObject(Expr *syntacticBase);
 315
 316    bool findAtIndexGetter();
 317    bool findAtIndexSetter();
 318
 319    ExprResult buildGet();
 320    ExprResult buildSet(Expr *op, SourceLocation, bool);
 321  };
 322
 323  class MSPropertyOpBuilder : public PseudoOpBuilder {
 324    MSPropertyRefExpr *RefExpr;
 325
 326  public:
 327    MSPropertyOpBuilder(Sema &S, MSPropertyRefExpr *refExpr) :
 328      PseudoOpBuilder(S, refExpr->getSourceRange().getBegin()),
 329      RefExpr(refExpr) {}
 330
 331    Expr *rebuildAndCaptureObject(Expr *);
 332    ExprResult buildGet();
 333    ExprResult buildSet(Expr *op, SourceLocation, bool);
 334  };
 335 }
 336
 337 /// Capture the given expression in an OpaqueValueExpr.
 338 OpaqueValueExpr *PseudoOpBuilder::capture(Expr *e) {
 339   // Make a new OVE whose source is the given expression.
 340   OpaqueValueExpr *captured =
 341     new (S.Context) OpaqueValueExpr(GenericLoc, e->getType(),
 342                                     e->getValueKind(), e->getObjectKind(),
 343                                     e);
 344
 345   // Make sure we bind that in the semantics.
 346   addSemanticExpr(captured);
 347   return captured;
 348 }
 349
 350 /// Capture the given expression as the result of this pseudo-object
 351 /// operation.  This routine is safe against expressions which may
 352 /// already be captured.
 353 ///
 354 /// \returns the captured expression, which will be the
 355 ///   same as the input if the input was already captured
 356 OpaqueValueExpr *PseudoOpBuilder::captureValueAsResult(Expr *e) {
 357   assert(ResultIndex == PseudoObjectExpr::NoResult);
 358
 359   // If the expression hasn't already been captured, just capture it
 360   // and set the new semantic
 361   if (!isa<OpaqueValueExpr>(e)) {
 362     OpaqueValueExpr *cap = capture(e);
 363     setResultToLastSemantic();
 364     return cap;
 365   }
 366
 367   // Otherwise, it must already be one of our semantic expressions;
 368   // set ResultIndex to its index.
 369   unsigned index = 0;
 370   for (;; ++index) {
 371     assert(index < Semantics.size() &&
 372            "captured expression not found in semantics!");
 373     if (e == Semantics[index]) break;
 374   }
 375   ResultIndex = index;
 376   return cast<OpaqueValueExpr>(e);
 377 }
 378
 379 /// The routine which creates the final PseudoObjectExpr.
 380 ExprResult PseudoOpBuilder::complete(Expr *syntactic) {
 381   return PseudoObjectExpr::Create(S.Context, syntactic,
 382                                   Semantics, ResultIndex);
 383 }
 384
 385 /// The main skeleton for building an r-value operation.
 386 ExprResult PseudoOpBuilder::buildRValueOperation(Expr *op) {
 387   Expr *syntacticBase = rebuildAndCaptureObject(op);
 388
 389   ExprResult getExpr = buildGet();
 390   if (getExpr.isInvalid()) return ExprError();
 391   addResultSemanticExpr(getExpr.take());
 392
 393   return complete(syntacticBase);
 394 }
 395
 396 /// The basic skeleton for building a simple or compound
 397 /// assignment operation.
 398 ExprResult
 399 PseudoOpBuilder::buildAssignmentOperation(Scope *Sc, SourceLocation opcLoc,
 400                                           BinaryOperatorKind opcode,
 401                                           Expr *LHS, Expr *RHS) {
 402   assert(BinaryOperator::isAssignmentOp(opcode));
 403
 404   Expr *syntacticLHS = rebuildAndCaptureObject(LHS);
 405   OpaqueValueExpr *capturedRHS = capture(RHS);
 406
 407   Expr *syntactic;
 408
 409   ExprResult result;
 410   if (opcode == BO_Assign) {
 411     result = capturedRHS;
 412     syntactic = new (S.Context) BinaryOperator(syntacticLHS, capturedRHS,
 413                                                opcode, capturedRHS->getType(),
 414                                                capturedRHS->getValueKind(),
 415                                                OK_Ordinary, opcLoc, false);
 416   } else {
 417     ExprResult opLHS = buildGet();
 418     if (opLHS.isInvalid()) return ExprError();
 419
 420     // Build an ordinary, non-compound operation.
 421     BinaryOperatorKind nonCompound =
 422       BinaryOperator::getOpForCompoundAssignment(opcode);
 423     result = S.BuildBinOp(Sc, opcLoc, nonCompound,
 424                           opLHS.take(), capturedRHS);
 425     if (result.isInvalid()) return ExprError();
 426
 427     syntactic =
 428       new (S.Context) CompoundAssignOperator(syntacticLHS, capturedRHS, opcode,
 429                                              result.get()->getType(),
 430                                              result.get()->getValueKind(),
 431                                              OK_Ordinary,
 432                                              opLHS.get()->getType(),
 433                                              result.get()->getType(),
 434                                              opcLoc, false);
 435   }
 436
 437   // The result of the assignment, if not void, is the value set into
 438   // the l-value.
 439   result = buildSet(result.take(), opcLoc, /*captureSetValueAsResult*/ true);
 440   if (result.isInvalid()) return ExprError();
 441   addSemanticExpr(result.take());
 442
 443   return complete(syntactic);
 444 }
 445
 446 /// The basic skeleton for building an increment or decrement
 447 /// operation.
 448 ExprResult
 449 PseudoOpBuilder::buildIncDecOperation(Scope *Sc, SourceLocation opcLoc,
 450                                       UnaryOperatorKind opcode,
 451                                       Expr *op) {
 452   assert(UnaryOperator::isIncrementDecrementOp(opcode));
 453
 454   Expr *syntacticOp = rebuildAndCaptureObject(op);
 455
 456   // Load the value.
 457   ExprResult result = buildGet();
 458   if (result.isInvalid()) return ExprError();
 459
 460   QualType resultType = result.get()->getType();
 461
 462   // That's the postfix result.
 463   if (UnaryOperator::isPostfix(opcode) &&
 464       (result.get()->isTypeDependent() || CanCaptureValueOfType(resultType))) {
 465     result = capture(result.take());
 466     setResultToLastSemantic();
 467   }
 468
 469   // Add or subtract a literal 1.
 470   llvm::APInt oneV(S.Context.getTypeSize(S.Context.IntTy), 1);
 471   Expr *one = IntegerLiteral::Create(S.Context, oneV, S.Context.IntTy,
 472                                      GenericLoc);
 473
 474   if (UnaryOperator::isIncrementOp(opcode)) {
 475     result = S.BuildBinOp(Sc, opcLoc, BO_Add, result.take(), one);
 476   } else {
 477     result = S.BuildBinOp(Sc, opcLoc, BO_Sub, result.take(), one);
 478   }
 479   if (result.isInvalid()) return ExprError();
 480
 481   // Store that back into the result.  The value stored is the result
 482   // of a prefix operation.
 483   result = buildSet(result.take(), opcLoc, UnaryOperator::isPrefix(opcode));
 484   if (result.isInvalid()) return ExprError();
 485   addSemanticExpr(result.take());
 486
 487   UnaryOperator *syntactic =
 488     new (S.Context) UnaryOperator(syntacticOp, opcode, resultType,
 489                                   VK_LValue, OK_Ordinary, opcLoc);
 490   return complete(syntactic);
 491 }
 492
 493
 494 //===----------------------------------------------------------------------===//
 495 //  Objective-C @property and implicit property references
 496 //===----------------------------------------------------------------------===//
 497
 498 /// Look up a method in the receiver type of an Objective-C property
 499 /// reference.
 500 static ObjCMethodDecl *LookupMethodInReceiverType(Sema &S, Selector sel,
 501                                             const ObjCPropertyRefExpr *PRE) {
 502   if (PRE->isObjectReceiver()) {
 503     const ObjCObjectPointerType *PT =
 504       PRE->getBase()->getType()->castAs<ObjCObjectPointerType>();
 505
 506     // Special case for 'self' in class method implementations.
 507     if (PT->isObjCClassType() &&
 508         S.isSelfExpr(const_cast<Expr*>(PRE->getBase()))) {
 509       // This cast is safe because isSelfExpr is only true within
 510       // methods.
 511       ObjCMethodDecl *method =
 512         cast<ObjCMethodDecl>(S.CurContext->getNonClosureAncestor());
 513       return S.LookupMethodInObjectType(sel,
 514                  S.Context.getObjCInterfaceType(method->getClassInterface()),
 515                                         /*instance*/ false);
 516     }
 517
 518     return S.LookupMethodInObjectType(sel, PT->getPointeeType(), true);
 519   }
 520
 521   if (PRE->isSuperReceiver()) {
 522     if (const ObjCObjectPointerType *PT =
 523         PRE->getSuperReceiverType()->getAs<ObjCObjectPointerType>())
 524       return S.LookupMethodInObjectType(sel, PT->getPointeeType(), true);
 525
 526     return S.LookupMethodInObjectType(sel, PRE->getSuperReceiverType(), false);
 527   }
 528
 529   assert(PRE->isClassReceiver() && "Invalid expression");
 530   QualType IT = S.Context.getObjCInterfaceType(PRE->getClassReceiver());
 531   return S.LookupMethodInObjectType(sel, IT, false);
 532 }
 533
 534 bool ObjCPropertyOpBuilder::isWeakProperty() const {
 535   QualType T;
 536   if (RefExpr->isExplicitProperty()) {
 537     const ObjCPropertyDecl *Prop = RefExpr->getExplicitProperty();
 538     if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak)
 539       return true;
 540
 541     T = Prop->getType();
 542   } else if (Getter) {
 543     T = Getter->getResultType();
 544   } else {
 545     return false;
 546   }
 547
 548   return T.getObjCLifetime() == Qualifiers::OCL_Weak;
 549 }
 550
 551 bool ObjCPropertyOpBuilder::findGetter() {
 552   if (Getter) return true;
 553
 554   // For implicit properties, just trust the lookup we already did.
 555   if (RefExpr->isImplicitProperty()) {
 556     if ((Getter = RefExpr->getImplicitPropertyGetter())) {
 557       GetterSelector = Getter->getSelector();
 558       return true;
 559     }
 560     else {
 561       // Must build the getter selector the hard way.
 562       ObjCMethodDecl *setter = RefExpr->getImplicitPropertySetter();
 563       assert(setter && "both setter and getter are null - cannot happen");
 564       IdentifierInfo *setterName =
 565         setter->getSelector().getIdentifierInfoForSlot(0);
 566       const char *compStr = setterName->getNameStart();
 567       compStr += 3;
 568       IdentifierInfo *getterName = &S.Context.Idents.get(compStr);
 569       GetterSelector =
 570         S.PP.getSelectorTable().getNullarySelector(getterName);
 571       return false;
 572
 573     }
 574   }
 575
 576   ObjCPropertyDecl *prop = RefExpr->getExplicitProperty();
 577   Getter = LookupMethodInReceiverType(S, prop->getGetterName(), RefExpr);
 578   return (Getter != 0);
 579 }
 580
 581 /// Try to find the most accurate setter declaration for the property
 582 /// reference.
 583 ///
 584 /// \return true if a setter was found, in which case Setter
 585 bool ObjCPropertyOpBuilder::findSetter(bool warn) {
 586   // For implicit properties, just trust the lookup we already did.
 587   if (RefExpr->isImplicitProperty()) {
 588     if (ObjCMethodDecl *setter = RefExpr->getImplicitPropertySetter()) {
 589       Setter = setter;
 590       SetterSelector = setter->getSelector();
 591       return true;
 592     } else {
 593       IdentifierInfo *getterName =
 594         RefExpr->getImplicitPropertyGetter()->getSelector()
 595           .getIdentifierInfoForSlot(0);
 596       SetterSelector =
 597         SelectorTable::constructSetterSelector(S.PP.getIdentifierTable(),
 598                                                S.PP.getSelectorTable(),
 599                                                getterName);
 600       return false;
 601     }
 602   }
 603
 604   // For explicit properties, this is more involved.
 605   ObjCPropertyDecl *prop = RefExpr->getExplicitProperty();
 606   SetterSelector = prop->getSetterName();
 607
 608   // Do a normal method lookup first.
 609   if (ObjCMethodDecl *setter =
 610         LookupMethodInReceiverType(S, SetterSelector, RefExpr)) {
 611     if (setter->isPropertyAccessor() && warn)
 612       if (const ObjCInterfaceDecl *IFace =
 613           dyn_cast<ObjCInterfaceDecl>(setter->getDeclContext())) {
 614         const StringRef thisPropertyName(prop->getName());
 615         // Try flipping the case of the first character.
 616         char front = thisPropertyName.front();
 617         front = isLowercase(front) ? toUppercase(front) : toLowercase(front);
 618         SmallString<100> PropertyName = thisPropertyName;
 619         PropertyName[0] = front;
 620         IdentifierInfo *AltMember = &S.PP.getIdentifierTable().get(PropertyName);
 621         if (ObjCPropertyDecl *prop1 = IFace->FindPropertyDeclaration(AltMember))
 622           if (prop != prop1 && (prop1->getSetterMethodDecl() == setter)) {
 623             S.Diag(RefExpr->getExprLoc(), diag::error_property_setter_ambiguous_use)
 624               << prop->getName() << prop1->getName() << setter->getSelector();
 625             S.Diag(prop->getLocation(), diag::note_property_declare);
 626             S.Diag(prop1->getLocation(), diag::note_property_declare);
 627           }
 628       }
 629     Setter = setter;
 630     return true;
 631   }
 632
 633   // That can fail in the somewhat crazy situation that we're
 634   // type-checking a message send within the @interface declaration
 635   // that declared the @property.  But it's not clear that that's
 636   // valuable to support.
 637
 638   return false;
 639 }
 640
 641 /// Capture the base object of an Objective-C property expression.
 642 Expr *ObjCPropertyOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
 643   assert(InstanceReceiver == 0);
 644
 645   // If we have a base, capture it in an OVE and rebuild the syntactic
 646   // form to use the OVE as its base.
 647   if (RefExpr->isObjectReceiver()) {
 648     InstanceReceiver = capture(RefExpr->getBase());
 649
 650     syntacticBase =
 651       ObjCPropertyRefRebuilder(S, InstanceReceiver).rebuild(syntacticBase);
 652   }
 653
 654   if (ObjCPropertyRefExpr *
 655         refE = dyn_cast<ObjCPropertyRefExpr>(syntacticBase->IgnoreParens()))
 656     SyntacticRefExpr = refE;
 657
 658   return syntacticBase;
 659 }
 660
 661 /// Load from an Objective-C property reference.
 662 ExprResult ObjCPropertyOpBuilder::buildGet() {
 663   findGetter();
 664   assert(Getter);
 665
 666   if (SyntacticRefExpr)
 667     SyntacticRefExpr->setIsMessagingGetter();
 668
 669   QualType receiverType;
 670   if (RefExpr->isClassReceiver()) {
 671     receiverType = S.Context.getObjCInterfaceType(RefExpr->getClassReceiver());
 672   } else if (RefExpr->isSuperReceiver()) {
 673     receiverType = RefExpr->getSuperReceiverType();
 674   } else {
 675     assert(InstanceReceiver);
 676     receiverType = InstanceReceiver->getType();
 677   }
 678
 679   // Build a message-send.
 680   ExprResult msg;
 681   if (Getter->isInstanceMethod() || RefExpr->isObjectReceiver()) {
 682     assert(InstanceReceiver || RefExpr->isSuperReceiver());
 683     msg = S.BuildInstanceMessageImplicit(InstanceReceiver, receiverType,
 684                                          GenericLoc, Getter->getSelector(),
 685                                          Getter, None);
 686   } else {
 687     msg = S.BuildClassMessageImplicit(receiverType, RefExpr->isSuperReceiver(),
 688                                       GenericLoc, Getter->getSelector(),
 689                                       Getter, None);
 690   }
 691   return msg;
 692 }
 693
 694 /// Store to an Objective-C property reference.
 695 ///
 696 /// \param captureSetValueAsResult If true, capture the actual
 697 ///   value being set as the value of the property operation.
 698 ExprResult ObjCPropertyOpBuilder::buildSet(Expr *op, SourceLocation opcLoc,
 699                                            bool captureSetValueAsResult) {
 700   bool hasSetter = findSetter(false);
 701   assert(hasSetter); (void) hasSetter;
 702
 703   if (SyntacticRefExpr)
 704     SyntacticRefExpr->setIsMessagingSetter();
 705
 706   QualType receiverType;
 707   if (RefExpr->isClassReceiver()) {
 708     receiverType = S.Context.getObjCInterfaceType(RefExpr->getClassReceiver());
 709   } else if (RefExpr->isSuperReceiver()) {
 710     receiverType = RefExpr->getSuperReceiverType();
 711   } else {
 712     assert(InstanceReceiver);
 713     receiverType = InstanceReceiver->getType();
 714   }
 715
 716   // Use assignment constraints when possible; they give us better
 717   // diagnostics.  "When possible" basically means anything except a
 718   // C++ class type.
 719   if (!S.getLangOpts().CPlusPlus || !op->getType()->isRecordType()) {
 720     QualType paramType = (*Setter->param_begin())->getType();
 721     if (!S.getLangOpts().CPlusPlus || !paramType->isRecordType()) {
 722       ExprResult opResult = op;
 723       Sema::AssignConvertType assignResult
 724         = S.CheckSingleAssignmentConstraints(paramType, opResult);
 725       if (S.DiagnoseAssignmentResult(assignResult, opcLoc, paramType,
 726                                      op->getType(), opResult.get(),
 727                                      Sema::AA_Assigning))
 728         return ExprError();
 729
 730       op = opResult.take();
 731       assert(op && "successful assignment left argument invalid?");
 732     }
 733     else if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(op)) {
 734       Expr *Initializer = OVE->getSourceExpr();
 735       // passing C++11 style initialized temporaries to objc++ properties
 736       // requires special treatment by removing OpaqueValueExpr so type
 737       // conversion takes place and adding the OpaqueValueExpr later on.
 738       if (isa<InitListExpr>(Initializer) &&
 739           Initializer->getType()->isVoidType()) {
 740         op = Initializer;
 741       }
 742     }
 743   }
 744
 745   // Arguments.
 746   Expr *args[] = { op };
 747
 748   // Build a message-send.
 749   ExprResult msg;
 750   if (Setter->isInstanceMethod() || RefExpr->isObjectReceiver()) {
 751     msg = S.BuildInstanceMessageImplicit(InstanceReceiver, receiverType,
 752                                          GenericLoc, SetterSelector, Setter,
 753                                          MultiExprArg(args, 1));
 754   } else {
 755     msg = S.BuildClassMessageImplicit(receiverType, RefExpr->isSuperReceiver(),
 756                                       GenericLoc,
 757                                       SetterSelector, Setter,
 758                                       MultiExprArg(args, 1));
 759   }
 760
 761   if (!msg.isInvalid() && captureSetValueAsResult) {
 762     ObjCMessageExpr *msgExpr =
 763       cast<ObjCMessageExpr>(msg.get()->IgnoreImplicit());
 764     Expr *arg = msgExpr->getArg(0);
 765     if (CanCaptureValueOfType(arg->getType()))
 766       msgExpr->setArg(0, captureValueAsResult(arg));
 767   }
 768
 769   return msg;
 770 }
 771
 772 /// @property-specific behavior for doing lvalue-to-rvalue conversion.
 773 ExprResult ObjCPropertyOpBuilder::buildRValueOperation(Expr *op) {
 774   // Explicit properties always have getters, but implicit ones don't.
 775   // Check that before proceeding.
 776   if (RefExpr->isImplicitProperty() && !RefExpr->getImplicitPropertyGetter()) {
 777     S.Diag(RefExpr->getLocation(), diag::err_getter_not_found)
 778         << RefExpr->getSourceRange();
 779     return ExprError();
 780   }
 781
 782   ExprResult result = PseudoOpBuilder::buildRValueOperation(op);
 783   if (result.isInvalid()) return ExprError();
 784
 785   if (RefExpr->isExplicitProperty() && !Getter->hasRelatedResultType())
 786     S.DiagnosePropertyAccessorMismatch(RefExpr->getExplicitProperty(),
 787                                        Getter, RefExpr->getLocation());
 788
 789   // As a special case, if the method returns 'id', try to get
 790   // a better type from the property.
 791   if (RefExpr->isExplicitProperty() && result.get()->isRValue() &&
 792       result.get()->getType()->isObjCIdType()) {
 793     QualType propType = RefExpr->getExplicitProperty()->getType();
 794     if (const ObjCObjectPointerType *ptr
 795           = propType->getAs<ObjCObjectPointerType>()) {
 796       if (!ptr->isObjCIdType())
 797         result = S.ImpCastExprToType(result.get(), propType, CK_BitCast);
 798     }
 799   }
 800
 801   return result;
 802 }
 803
 804 /// Try to build this as a call to a getter that returns a reference.
 805 ///
 806 /// \return true if it was possible, whether or not it actually
 807 ///   succeeded
 808 bool ObjCPropertyOpBuilder::tryBuildGetOfReference(Expr *op,
 809                                                    ExprResult &result) {
 810   if (!S.getLangOpts().CPlusPlus) return false;
 811
 812   findGetter();
 813   assert(Getter && "property has no setter and no getter!");
 814
 815   // Only do this if the getter returns an l-value reference type.
 816   QualType resultType = Getter->getResultType();
 817   if (!resultType->isLValueReferenceType()) return false;
 818
 819   result = buildRValueOperation(op);
 820   return true;
 821 }
 822
 823 /// @property-specific behavior for doing assignments.
 824 ExprResult
 825 ObjCPropertyOpBuilder::buildAssignmentOperation(Scope *Sc,
 826                                                 SourceLocation opcLoc,
 827                                                 BinaryOperatorKind opcode,
 828                                                 Expr *LHS, Expr *RHS) {
 829   assert(BinaryOperator::isAssignmentOp(opcode));
 830
 831   // If there's no setter, we have no choice but to try to assign to
 832   // the result of the getter.
 833   if (!findSetter()) {
 834     ExprResult result;
 835     if (tryBuildGetOfReference(LHS, result)) {
 836       if (result.isInvalid()) return ExprError();
 837       return S.BuildBinOp(Sc, opcLoc, opcode, result.take(), RHS);
 838     }
 839
 840     // Otherwise, it's an error.
 841     S.Diag(opcLoc, diag::err_nosetter_property_assignment)
 842       << unsigned(RefExpr->isImplicitProperty())
 843       << SetterSelector
 844       << LHS->getSourceRange() << RHS->getSourceRange();
 845     return ExprError();
 846   }
 847
 848   // If there is a setter, we definitely want to use it.
 849
 850   // Verify that we can do a compound assignment.
 851   if (opcode != BO_Assign && !findGetter()) {
 852     S.Diag(opcLoc, diag::err_nogetter_property_compound_assignment)
 853       << LHS->getSourceRange() << RHS->getSourceRange();
 854     return ExprError();
 855   }
 856
 857   ExprResult result =
 858     PseudoOpBuilder::buildAssignmentOperation(Sc, opcLoc, opcode, LHS, RHS);
 859   if (result.isInvalid()) return ExprError();
 860
 861   // Various warnings about property assignments in ARC.
 862   if (S.getLangOpts().ObjCAutoRefCount && InstanceReceiver) {
 863     S.checkRetainCycles(InstanceReceiver->getSourceExpr(), RHS);
 864     S.checkUnsafeExprAssigns(opcLoc, LHS, RHS);
 865   }
 866
 867   return result;
 868 }
 869
 870 /// @property-specific behavior for doing increments and decrements.
 871 ExprResult
 872 ObjCPropertyOpBuilder::buildIncDecOperation(Scope *Sc, SourceLocation opcLoc,
 873                                             UnaryOperatorKind opcode,
 874                                             Expr *op) {
 875   // If there's no setter, we have no choice but to try to assign to
 876   // the result of the getter.
 877   if (!findSetter()) {
 878     ExprResult result;
 879     if (tryBuildGetOfReference(op, result)) {
 880       if (result.isInvalid()) return ExprError();
 881       return S.BuildUnaryOp(Sc, opcLoc, opcode, result.take());
 882     }
 883
 884     // Otherwise, it's an error.
 885     S.Diag(opcLoc, diag::err_nosetter_property_incdec)
 886       << unsigned(RefExpr->isImplicitProperty())
 887       << unsigned(UnaryOperator::isDecrementOp(opcode))
 888       << SetterSelector
 889       << op->getSourceRange();
 890     return ExprError();
 891   }
 892
 893   // If there is a setter, we definitely want to use it.
 894
 895   // We also need a getter.
 896   if (!findGetter()) {
 897     assert(RefExpr->isImplicitProperty());
 898     S.Diag(opcLoc, diag::err_nogetter_property_incdec)
 899       << unsigned(UnaryOperator::isDecrementOp(opcode))
 900       << GetterSelector
 901       << op->getSourceRange();
 902     return ExprError();
 903   }
 904
 905   return PseudoOpBuilder::buildIncDecOperation(Sc, opcLoc, opcode, op);
 906 }
 907
 908 ExprResult ObjCPropertyOpBuilder::complete(Expr *SyntacticForm) {
 909   if (S.getLangOpts().ObjCAutoRefCount && isWeakProperty()) {
 910     DiagnosticsEngine::Level Level =
 911       S.Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak,
 912                                  SyntacticForm->getLocStart());
 913     if (Level != DiagnosticsEngine::Ignored)
 914       S.recordUseOfEvaluatedWeak(SyntacticRefExpr,
 915                                  SyntacticRefExpr->isMessagingGetter());
 916   }
 917
 918   return PseudoOpBuilder::complete(SyntacticForm);
 919 }
 920
 921 // ObjCSubscript build stuff.
 922 //
 923
 924 /// objective-c subscripting-specific behavior for doing lvalue-to-rvalue
 925 /// conversion.
 926 /// FIXME. Remove this routine if it is proven that no additional
 927 /// specifity is needed.
 928 ExprResult ObjCSubscriptOpBuilder::buildRValueOperation(Expr *op) {
 929   ExprResult result = PseudoOpBuilder::buildRValueOperation(op);
 930   if (result.isInvalid()) return ExprError();
 931   return result;
 932 }
 933
 934 /// objective-c subscripting-specific  behavior for doing assignments.
 935 ExprResult
 936 ObjCSubscriptOpBuilder::buildAssignmentOperation(Scope *Sc,
 937                                                 SourceLocation opcLoc,
 938                                                 BinaryOperatorKind opcode,
 939                                                 Expr *LHS, Expr *RHS) {
 940   assert(BinaryOperator::isAssignmentOp(opcode));
 941   // There must be a method to do the Index'ed assignment.
 942   if (!findAtIndexSetter())
 943     return ExprError();
 944
 945   // Verify that we can do a compound assignment.
 946   if (opcode != BO_Assign && !findAtIndexGetter())
 947     return ExprError();
 948
 949   ExprResult result =
 950   PseudoOpBuilder::buildAssignmentOperation(Sc, opcLoc, opcode, LHS, RHS);
 951   if (result.isInvalid()) return ExprError();
 952
 953   // Various warnings about objc Index'ed assignments in ARC.
 954   if (S.getLangOpts().ObjCAutoRefCount && InstanceBase) {
 955     S.checkRetainCycles(InstanceBase->getSourceExpr(), RHS);
 956     S.checkUnsafeExprAssigns(opcLoc, LHS, RHS);
 957   }
 958
 959   return result;
 960 }
 961
 962 /// Capture the base object of an Objective-C Index'ed expression.
 963 Expr *ObjCSubscriptOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
 964   assert(InstanceBase == 0);
 965
 966   // Capture base expression in an OVE and rebuild the syntactic
 967   // form to use the OVE as its base expression.
 968   InstanceBase = capture(RefExpr->getBaseExpr());
 969   InstanceKey = capture(RefExpr->getKeyExpr());
 970
 971   syntacticBase =
 972     ObjCSubscriptRefRebuilder(S, InstanceBase,
 973                               InstanceKey).rebuild(syntacticBase);
 974
 975   return syntacticBase;
 976 }
 977
 978 /// CheckSubscriptingKind - This routine decide what type
 979 /// of indexing represented by "FromE" is being done.
 980 Sema::ObjCSubscriptKind
 981   Sema::CheckSubscriptingKind(Expr *FromE) {
 982   // If the expression already has integral or enumeration type, we're golden.
 983   QualType T = FromE->getType();
 984   if (T->isIntegralOrEnumerationType())
 985     return OS_Array;
 986
 987   // If we don't have a class type in C++, there's no way we can get an
 988   // expression of integral or enumeration type.
 989   const RecordType *RecordTy = T->getAs<RecordType>();
 990   if (!RecordTy && T->isObjCObjectPointerType())
 991     // All other scalar cases are assumed to be dictionary indexing which
 992     // caller handles, with diagnostics if needed.
 993     return OS_Dictionary;
 994   if (!getLangOpts().CPlusPlus ||
 995       !RecordTy || RecordTy->isIncompleteType()) {
 996     // No indexing can be done. Issue diagnostics and quit.
 997     const Expr *IndexExpr = FromE->IgnoreParenImpCasts();
 998     if (isa<StringLiteral>(IndexExpr))
 999       Diag(FromE->getExprLoc(), diag::err_objc_subscript_pointer)
1000         << T << FixItHint::CreateInsertion(FromE->getExprLoc(), "@");
1001     else
1002       Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
1003         << T;
1004     return OS_Error;
1005   }
1006
1007   // We must have a complete class type.
1008   if (RequireCompleteType(FromE->getExprLoc(), T,
1009                           diag::err_objc_index_incomplete_class_type, FromE))
1010     return OS_Error;
1011
1012   // Look for a conversion to an integral, enumeration type, or
1013   // objective-C pointer type.
1014   UnresolvedSet<4> ViableConversions;
1015   UnresolvedSet<4> ExplicitConversions;
1016   std::pair<CXXRecordDecl::conversion_iterator,
1017             CXXRecordDecl::conversion_iterator> Conversions
1018     = cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();
1019
1020   int NoIntegrals=0, NoObjCIdPointers=0;
1021   SmallVector<CXXConversionDecl *, 4> ConversionDecls;
1022
1023   for (CXXRecordDecl::conversion_iterator
1024          I = Conversions.first, E = Conversions.second; I != E; ++I) {
1025     if (CXXConversionDecl *Conversion
1026         = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) {
1027       QualType CT = Conversion->getConversionType().getNonReferenceType();
1028       if (CT->isIntegralOrEnumerationType()) {
1029         ++NoIntegrals;
1030         ConversionDecls.push_back(Conversion);
1031       }
1032       else if (CT->isObjCIdType() ||CT->isBlockPointerType()) {
1033         ++NoObjCIdPointers;
1034         ConversionDecls.push_back(Conversion);
1035       }
1036     }
1037   }
1038   if (NoIntegrals ==1 && NoObjCIdPointers == 0)
1039     return OS_Array;
1040   if (NoIntegrals == 0 && NoObjCIdPointers == 1)
1041     return OS_Dictionary;
1042   if (NoIntegrals == 0 && NoObjCIdPointers == 0) {
1043     // No conversion function was found. Issue diagnostic and return.
1044     Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
1045       << FromE->getType();
1046     return OS_Error;
1047   }
1048   Diag(FromE->getExprLoc(), diag::err_objc_multiple_subscript_type_conversion)
1049       << FromE->getType();
1050   for (unsigned int i = 0; i < ConversionDecls.size(); i++)
1051     Diag(ConversionDecls[i]->getLocation(), diag::not_conv_function_declared_at);
1052
1053   return OS_Error;
1054 }
1055
1056 /// CheckKeyForObjCARCConversion - This routine suggests bridge casting of CF
1057 /// objects used as dictionary subscript key objects.
1058 static void CheckKeyForObjCARCConversion(Sema &S, QualType ContainerT,
1059                                          Expr *Key) {
1060   if (ContainerT.isNull())
1061     return;
1062   // dictionary subscripting.
1063   // - (id)objectForKeyedSubscript:(id)key;
1064   IdentifierInfo *KeyIdents[] = {
1065     &S.Context.Idents.get("objectForKeyedSubscript")
1066   };
1067   Selector GetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
1068   ObjCMethodDecl *Getter = S.LookupMethodInObjectType(GetterSelector, ContainerT,
1069                                                       true /*instance*/);
1070   if (!Getter)
1071     return;
1072   QualType T = Getter->param_begin()[0]->getType();
1073   S.CheckObjCARCConversion(Key->getSourceRange(),
1074                          T, Key, Sema::CCK_ImplicitConversion);
1075 }
1076
1077 bool ObjCSubscriptOpBuilder::findAtIndexGetter() {
1078   if (AtIndexGetter)
1079     return true;
1080
1081   Expr *BaseExpr = RefExpr->getBaseExpr();
1082   QualType BaseT = BaseExpr->getType();
1083
1084   QualType ResultType;
1085   if (const ObjCObjectPointerType *PTy =
1086       BaseT->getAs<ObjCObjectPointerType>()) {
1087     ResultType = PTy->getPointeeType();
1088     if (const ObjCObjectType *iQFaceTy =
1089         ResultType->getAsObjCQualifiedInterfaceType())
1090       ResultType = iQFaceTy->getBaseType();
1091   }
1092   Sema::ObjCSubscriptKind Res =
1093     S.CheckSubscriptingKind(RefExpr->getKeyExpr());
1094   if (Res == Sema::OS_Error) {
1095     if (S.getLangOpts().ObjCAutoRefCount)
1096       CheckKeyForObjCARCConversion(S, ResultType,
1097                                    RefExpr->getKeyExpr());
1098     return false;
1099   }
1100   bool arrayRef = (Res == Sema::OS_Array);
1101
1102   if (ResultType.isNull()) {
1103     S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
1104       << BaseExpr->getType() << arrayRef;
1105     return false;
1106   }
1107   if (!arrayRef) {
1108     // dictionary subscripting.
1109     // - (id)objectForKeyedSubscript:(id)key;
1110     IdentifierInfo *KeyIdents[] = {
1111       &S.Context.Idents.get("objectForKeyedSubscript")
1112     };
1113     AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
1114   }
1115   else {
1116     // - (id)objectAtIndexedSubscript:(size_t)index;
1117     IdentifierInfo *KeyIdents[] = {
1118       &S.Context.Idents.get("objectAtIndexedSubscript")
1119     };
1120
1121     AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
1122   }
1123
1124   AtIndexGetter = S.LookupMethodInObjectType(AtIndexGetterSelector, ResultType,
1125                                              true /*instance*/);
1126   bool receiverIdType = (BaseT->isObjCIdType() ||
1127                          BaseT->isObjCQualifiedIdType());
1128
1129   if (!AtIndexGetter && S.getLangOpts().DebuggerObjCLiteral) {
1130     AtIndexGetter = ObjCMethodDecl::Create(S.Context, SourceLocation(),
1131                            SourceLocation(), AtIndexGetterSelector,
1132                            S.Context.getObjCIdType() /*ReturnType*/,
1133                            0 /*TypeSourceInfo */,
1134                            S.Context.getTranslationUnitDecl(),
1135                            true /*Instance*/, false/*isVariadic*/,
1136                            /*isPropertyAccessor=*/false,
1137                            /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
1138                            ObjCMethodDecl::Required,
1139                            false);
1140     ParmVarDecl *Argument = ParmVarDecl::Create(S.Context, AtIndexGetter,
1141                                                 SourceLocation(), SourceLocation(),
1142                                                 arrayRef ? &S.Context.Idents.get("index")
1143                                                          : &S.Context.Idents.get("key"),
1144                                                 arrayRef ? S.Context.UnsignedLongTy
1145                                                          : S.Context.getObjCIdType(),
1146                                                 /*TInfo=*/0,
1147                                                 SC_None,
1148                                                 0);
1149     AtIndexGetter->setMethodParams(S.Context, Argument, None);
1150   }
1151
1152   if (!AtIndexGetter) {
1153     if (!receiverIdType) {
1154       S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_method_not_found)
1155       << BaseExpr->getType() << 0 << arrayRef;
1156       return false;
1157     }
1158     AtIndexGetter =
1159       S.LookupInstanceMethodInGlobalPool(AtIndexGetterSelector,
1160                                          RefExpr->getSourceRange(),
1161                                          true, false);
1162   }
1163
1164   if (AtIndexGetter) {
1165     QualType T = AtIndexGetter->param_begin()[0]->getType();
1166     if ((arrayRef && !T->isIntegralOrEnumerationType()) ||
1167         (!arrayRef && !T->isObjCObjectPointerType())) {
1168       S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1169              arrayRef ? diag::err_objc_subscript_index_type
1170                       : diag::err_objc_subscript_key_type) << T;
1171       S.Diag(AtIndexGetter->param_begin()[0]->getLocation(),
1172              diag::note_parameter_type) << T;
1173       return false;
1174     }
1175     QualType R = AtIndexGetter->getResultType();
1176     if (!R->isObjCObjectPointerType()) {
1177       S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1178              diag::err_objc_indexing_method_result_type) << R << arrayRef;
1179       S.Diag(AtIndexGetter->getLocation(), diag::note_method_declared_at) <<
1180         AtIndexGetter->getDeclName();
1181     }
1182   }
1183   return true;
1184 }
1185
1186 bool ObjCSubscriptOpBuilder::findAtIndexSetter() {
1187   if (AtIndexSetter)
1188     return true;
1189
1190   Expr *BaseExpr = RefExpr->getBaseExpr();
1191   QualType BaseT = BaseExpr->getType();
1192
1193   QualType ResultType;
1194   if (const ObjCObjectPointerType *PTy =
1195       BaseT->getAs<ObjCObjectPointerType>()) {
1196     ResultType = PTy->getPointeeType();
1197     if (const ObjCObjectType *iQFaceTy =
1198         ResultType->getAsObjCQualifiedInterfaceType())
1199       ResultType = iQFaceTy->getBaseType();
1200   }
1201
1202   Sema::ObjCSubscriptKind Res =
1203     S.CheckSubscriptingKind(RefExpr->getKeyExpr());
1204   if (Res == Sema::OS_Error) {
1205     if (S.getLangOpts().ObjCAutoRefCount)
1206       CheckKeyForObjCARCConversion(S, ResultType,
1207                                    RefExpr->getKeyExpr());
1208     return false;
1209   }
1210   bool arrayRef = (Res == Sema::OS_Array);
1211
1212   if (ResultType.isNull()) {
1213     S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
1214       << BaseExpr->getType() << arrayRef;
1215     return false;
1216   }
1217
1218   if (!arrayRef) {
1219     // dictionary subscripting.
1220     // - (void)setObject:(id)object forKeyedSubscript:(id)key;
1221     IdentifierInfo *KeyIdents[] = {
1222       &S.Context.Idents.get("setObject"),
1223       &S.Context.Idents.get("forKeyedSubscript")
1224     };
1225     AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
1226   }
1227   else {
1228     // - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
1229     IdentifierInfo *KeyIdents[] = {
1230       &S.Context.Idents.get("setObject"),
1231       &S.Context.Idents.get("atIndexedSubscript")
1232     };
1233     AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
1234   }
1235   AtIndexSetter = S.LookupMethodInObjectType(AtIndexSetterSelector, ResultType,
1236                                              true /*instance*/);
1237
1238   bool receiverIdType = (BaseT->isObjCIdType() ||
1239                          BaseT->isObjCQualifiedIdType());
1240
1241   if (!AtIndexSetter && S.getLangOpts().DebuggerObjCLiteral) {
1242     TypeSourceInfo *ResultTInfo = 0;
1243     QualType ReturnType = S.Context.VoidTy;
1244     AtIndexSetter = ObjCMethodDecl::Create(S.Context, SourceLocation(),
1245                            SourceLocation(), AtIndexSetterSelector,
1246                            ReturnType,
1247                            ResultTInfo,
1248                            S.Context.getTranslationUnitDecl(),
1249                            true /*Instance*/, false/*isVariadic*/,
1250                            /*isPropertyAccessor=*/false,
1251                            /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
1252                            ObjCMethodDecl::Required,
1253                            false);
1254     SmallVector<ParmVarDecl *, 2> Params;
1255     ParmVarDecl *object = ParmVarDecl::Create(S.Context, AtIndexSetter,
1256                                                 SourceLocation(), SourceLocation(),
1257                                                 &S.Context.Idents.get("object"),
1258                                                 S.Context.getObjCIdType(),
1259                                                 /*TInfo=*/0,
1260                                                 SC_None,
1261                                                 0);
1262     Params.push_back(object);
1263     ParmVarDecl *key = ParmVarDecl::Create(S.Context, AtIndexSetter,
1264                                                 SourceLocation(), SourceLocation(),
1265                                                 arrayRef ?  &S.Context.Idents.get("index")
1266                                                          :  &S.Context.Idents.get("key"),
1267                                                 arrayRef ? S.Context.UnsignedLongTy
1268                                                          : S.Context.getObjCIdType(),
1269                                                 /*TInfo=*/0,
1270                                                 SC_None,
1271                                                 0);
1272     Params.push_back(key);
1273     AtIndexSetter->setMethodParams(S.Context, Params, None);
1274   }
1275
1276   if (!AtIndexSetter) {
1277     if (!receiverIdType) {
1278       S.Diag(BaseExpr->getExprLoc(),
1279              diag::err_objc_subscript_method_not_found)
1280       << BaseExpr->getType() << 1 << arrayRef;
1281       return false;
1282     }
1283     AtIndexSetter =
1284       S.LookupInstanceMethodInGlobalPool(AtIndexSetterSelector,
1285                                          RefExpr->getSourceRange(),
1286                                          true, false);
1287   }
1288
1289   bool err = false;
1290   if (AtIndexSetter && arrayRef) {
1291     QualType T = AtIndexSetter->param_begin()[1]->getType();
1292     if (!T->isIntegralOrEnumerationType()) {
1293       S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1294              diag::err_objc_subscript_index_type) << T;
1295       S.Diag(AtIndexSetter->param_begin()[1]->getLocation(),
1296              diag::note_parameter_type) << T;
1297       err = true;
1298     }
1299     T = AtIndexSetter->param_begin()[0]->getType();
1300     if (!T->isObjCObjectPointerType()) {
1301       S.Diag(RefExpr->getBaseExpr()->getExprLoc(),
1302              diag::err_objc_subscript_object_type) << T << arrayRef;
1303       S.Diag(AtIndexSetter->param_begin()[0]->getLocation(),
1304              diag::note_parameter_type) << T;
1305       err = true;
1306     }
1307   }
1308   else if (AtIndexSetter && !arrayRef)
1309     for (unsigned i=0; i <2; i++) {
1310       QualType T = AtIndexSetter->param_begin()[i]->getType();
1311       if (!T->isObjCObjectPointerType()) {
1312         if (i == 1)
1313           S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1314                  diag::err_objc_subscript_key_type) << T;
1315         else
1316           S.Diag(RefExpr->getBaseExpr()->getExprLoc(),
1317                  diag::err_objc_subscript_dic_object_type) << T;
1318         S.Diag(AtIndexSetter->param_begin()[i]->getLocation(),
1319                diag::note_parameter_type) << T;
1320         err = true;
1321       }
1322     }
1323
1324   return !err;
1325 }
1326
1327 // Get the object at "Index" position in the container.
1328 // [BaseExpr objectAtIndexedSubscript : IndexExpr];
1329 ExprResult ObjCSubscriptOpBuilder::buildGet() {
1330   if (!findAtIndexGetter())
1331     return ExprError();
1332
1333   QualType receiverType = InstanceBase->getType();
1334
1335   // Build a message-send.
1336   ExprResult msg;
1337   Expr *Index = InstanceKey;
1338
1339   // Arguments.
1340   Expr *args[] = { Index };
1341   assert(InstanceBase);
1342   msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
1343                                        GenericLoc,
1344                                        AtIndexGetterSelector, AtIndexGetter,
1345                                        MultiExprArg(args, 1));
1346   return msg;
1347 }
1348
1349 /// Store into the container the "op" object at "Index"'ed location
1350 /// by building this messaging expression:
1351 /// - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
1352 /// \param captureSetValueAsResult If true, capture the actual
1353 ///   value being set as the value of the property operation.
1354 ExprResult ObjCSubscriptOpBuilder::buildSet(Expr *op, SourceLocation opcLoc,
1355                                            bool captureSetValueAsResult) {
1356   if (!findAtIndexSetter())
1357     return ExprError();
1358
1359   QualType receiverType = InstanceBase->getType();
1360   Expr *Index = InstanceKey;
1361
1362   // Arguments.
1363   Expr *args[] = { op, Index };
1364
1365   // Build a message-send.
1366   ExprResult msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
1367                                                   GenericLoc,
1368                                                   AtIndexSetterSelector,
1369                                                   AtIndexSetter,
1370                                                   MultiExprArg(args, 2));
1371
1372   if (!msg.isInvalid() && captureSetValueAsResult) {
1373     ObjCMessageExpr *msgExpr =
1374       cast<ObjCMessageExpr>(msg.get()->IgnoreImplicit());
1375     Expr *arg = msgExpr->getArg(0);
1376     if (CanCaptureValueOfType(arg->getType()))
1377       msgExpr->setArg(0, captureValueAsResult(arg));
1378   }
1379
1380   return msg;
1381 }
1382
1383 //===----------------------------------------------------------------------===//
1384 //  MSVC __declspec(property) references
1385 //===----------------------------------------------------------------------===//
1386
1387 Expr *MSPropertyOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
1388   Expr *NewBase = capture(RefExpr->getBaseExpr());
1389
1390   syntacticBase =
1391     MSPropertyRefRebuilder(S, NewBase).rebuild(syntacticBase);
1392
1393   return syntacticBase;
1394 }
1395
1396 ExprResult MSPropertyOpBuilder::buildGet() {
1397   if (!RefExpr->getPropertyDecl()->hasGetter()) {
1398     S.Diag(RefExpr->getMemberLoc(), diag::err_no_getter_for_property)
1399       << RefExpr->getPropertyDecl()->getName();
1400     return ExprError();
1401   }
1402
1403   UnqualifiedId GetterName;
1404   IdentifierInfo *II = RefExpr->getPropertyDecl()->getGetterId();
1405   GetterName.setIdentifier(II, RefExpr->getMemberLoc());
1406   CXXScopeSpec SS;
1407   SS.Adopt(RefExpr->getQualifierLoc());
1408   ExprResult GetterExpr = S.ActOnMemberAccessExpr(
1409     S.getCurScope(), RefExpr->getBaseExpr(), SourceLocation(),
1410     RefExpr->isArrow() ? tok::arrow : tok::period, SS, SourceLocation(),
1411     GetterName, 0, true);
1412   if (GetterExpr.isInvalid()) {
1413     S.Diag(RefExpr->getMemberLoc(), diag::error_cannot_find_suitable_getter)
1414       << RefExpr->getPropertyDecl()->getName();
1415     return ExprError();
1416   }
1417
1418   MultiExprArg ArgExprs;
1419   return S.ActOnCallExpr(S.getCurScope(), GetterExpr.take(),
1420                          RefExpr->getSourceRange().getBegin(), ArgExprs,
1421                          RefExpr->getSourceRange().getEnd());
1422 }
1423
1424 ExprResult MSPropertyOpBuilder::buildSet(Expr *op, SourceLocation sl,
1425                                          bool captureSetValueAsResult) {
1426   if (!RefExpr->getPropertyDecl()->hasSetter()) {
1427     S.Diag(RefExpr->getMemberLoc(), diag::err_no_setter_for_property)
1428       << RefExpr->getPropertyDecl()->getName();
1429     return ExprError();
1430   }
1431
1432   UnqualifiedId SetterName;
1433   IdentifierInfo *II = RefExpr->getPropertyDecl()->getSetterId();
1434   SetterName.setIdentifier(II, RefExpr->getMemberLoc());
1435   CXXScopeSpec SS;
1436   SS.Adopt(RefExpr->getQualifierLoc());
1437   ExprResult SetterExpr = S.ActOnMemberAccessExpr(
1438     S.getCurScope(), RefExpr->getBaseExpr(), SourceLocation(),
1439     RefExpr->isArrow() ? tok::arrow : tok::period, SS, SourceLocation(),
1440     SetterName, 0, true);
1441   if (SetterExpr.isInvalid()) {
1442     S.Diag(RefExpr->getMemberLoc(), diag::error_cannot_find_suitable_setter)
1443       << RefExpr->getPropertyDecl()->getName();
1444     return ExprError();
1445   }
1446
1447   SmallVector<Expr*, 1> ArgExprs;
1448   ArgExprs.push_back(op);
1449   return S.ActOnCallExpr(S.getCurScope(), SetterExpr.take(),
1450                          RefExpr->getSourceRange().getBegin(), ArgExprs,
1451                          op->getSourceRange().getEnd());
1452 }
1453
1454 //===----------------------------------------------------------------------===//
1455 //  General Sema routines.
1456 //===----------------------------------------------------------------------===//
1457
1458 ExprResult Sema::checkPseudoObjectRValue(Expr *E) {
1459   Expr *opaqueRef = E->IgnoreParens();
1460   if (ObjCPropertyRefExpr *refExpr
1461         = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1462     ObjCPropertyOpBuilder builder(*this, refExpr);
1463     return builder.buildRValueOperation(E);
1464   }
1465   else if (ObjCSubscriptRefExpr *refExpr
1466            = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1467     ObjCSubscriptOpBuilder builder(*this, refExpr);
1468     return builder.buildRValueOperation(E);
1469   } else if (MSPropertyRefExpr *refExpr
1470              = dyn_cast<MSPropertyRefExpr>(opaqueRef)) {
1471     MSPropertyOpBuilder builder(*this, refExpr);
1472     return builder.buildRValueOperation(E);
1473   } else {
1474     llvm_unreachable("unknown pseudo-object kind!");
1475   }
1476 }
1477
1478 /// Check an increment or decrement of a pseudo-object expression.
1479 ExprResult Sema::checkPseudoObjectIncDec(Scope *Sc, SourceLocation opcLoc,
1480                                          UnaryOperatorKind opcode, Expr *op) {
1481   // Do nothing if the operand is dependent.
1482   if (op->isTypeDependent())
1483     return new (Context) UnaryOperator(op, opcode, Context.DependentTy,
1484                                        VK_RValue, OK_Ordinary, opcLoc);
1485
1486   assert(UnaryOperator::isIncrementDecrementOp(opcode));
1487   Expr *opaqueRef = op->IgnoreParens();
1488   if (ObjCPropertyRefExpr *refExpr
1489         = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1490     ObjCPropertyOpBuilder builder(*this, refExpr);
1491     return builder.buildIncDecOperation(Sc, opcLoc, opcode, op);
1492   } else if (isa<ObjCSubscriptRefExpr>(opaqueRef)) {
1493     Diag(opcLoc, diag::err_illegal_container_subscripting_op);
1494     return ExprError();
1495   } else if (MSPropertyRefExpr *refExpr
1496              = dyn_cast<MSPropertyRefExpr>(opaqueRef)) {
1497     MSPropertyOpBuilder builder(*this, refExpr);
1498     return builder.buildIncDecOperation(Sc, opcLoc, opcode, op);
1499   } else {
1500     llvm_unreachable("unknown pseudo-object kind!");
1501   }
1502 }
1503
1504 ExprResult Sema::checkPseudoObjectAssignment(Scope *S, SourceLocation opcLoc,
1505                                              BinaryOperatorKind opcode,
1506                                              Expr *LHS, Expr *RHS) {
1507   // Do nothing if either argument is dependent.
1508   if (LHS->isTypeDependent() || RHS->isTypeDependent())
1509     return new (Context) BinaryOperator(LHS, RHS, opcode, Context.DependentTy,
1510                                         VK_RValue, OK_Ordinary, opcLoc, false);
1511
1512   // Filter out non-overload placeholder types in the RHS.
1513   if (RHS->getType()->isNonOverloadPlaceholderType()) {
1514     ExprResult result = CheckPlaceholderExpr(RHS);
1515     if (result.isInvalid()) return ExprError();
1516     RHS = result.take();
1517   }
1518
1519   Expr *opaqueRef = LHS->IgnoreParens();
1520   if (ObjCPropertyRefExpr *refExpr
1521         = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1522     ObjCPropertyOpBuilder builder(*this, refExpr);
1523     return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
1524   } else if (ObjCSubscriptRefExpr *refExpr
1525              = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1526     ObjCSubscriptOpBuilder builder(*this, refExpr);
1527     return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
1528   } else if (MSPropertyRefExpr *refExpr
1529              = dyn_cast<MSPropertyRefExpr>(opaqueRef)) {
1530     MSPropertyOpBuilder builder(*this, refExpr);
1531     return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
1532   } else {
1533     llvm_unreachable("unknown pseudo-object kind!");
1534   }
1535 }
1536
1537 /// Given a pseudo-object reference, rebuild it without the opaque
1538 /// values.  Basically, undo the behavior of rebuildAndCaptureObject.
1539 /// This should never operate in-place.
1540 static Expr *stripOpaqueValuesFromPseudoObjectRef(Sema &S, Expr *E) {
1541   Expr *opaqueRef = E->IgnoreParens();
1542   if (ObjCPropertyRefExpr *refExpr
1543         = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1544     // Class and super property references don't have opaque values in them.
1545     if (refExpr->isClassReceiver() || refExpr->isSuperReceiver())
1546       return E;
1547
1548     assert(refExpr->isObjectReceiver() && "Unknown receiver kind?");
1549     OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBase());
1550     return ObjCPropertyRefRebuilder(S, baseOVE->getSourceExpr()).rebuild(E);
1551   } else if (ObjCSubscriptRefExpr *refExpr
1552                = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1553     OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBaseExpr());
1554     OpaqueValueExpr *keyOVE = cast<OpaqueValueExpr>(refExpr->getKeyExpr());
1555     return ObjCSubscriptRefRebuilder(S, baseOVE->getSourceExpr(),
1556                                      keyOVE->getSourceExpr()).rebuild(E);
1557   } else if (MSPropertyRefExpr *refExpr
1558              = dyn_cast<MSPropertyRefExpr>(opaqueRef)) {
1559     OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBaseExpr());
1560     return MSPropertyRefRebuilder(S, baseOVE->getSourceExpr()).rebuild(E);
1561   } else {
1562     llvm_unreachable("unknown pseudo-object kind!");
1563   }
1564 }
1565
1566 /// Given a pseudo-object expression, recreate what it looks like
1567 /// syntactically without the attendant OpaqueValueExprs.
1568 ///
1569 /// This is a hack which should be removed when TreeTransform is
1570 /// capable of rebuilding a tree without stripping implicit
1571 /// operations.
1572 Expr *Sema::recreateSyntacticForm(PseudoObjectExpr *E) {
1573   Expr *syntax = E->getSyntacticForm();
1574   if (UnaryOperator *uop = dyn_cast<UnaryOperator>(syntax)) {
1575     Expr *op = stripOpaqueValuesFromPseudoObjectRef(*this, uop->getSubExpr());
1576     return new (Context) UnaryOperator(op, uop->getOpcode(), uop->getType(),
1577                                        uop->getValueKind(), uop->getObjectKind(),
1578                                        uop->getOperatorLoc());
1579   } else if (CompoundAssignOperator *cop
1580                = dyn_cast<CompoundAssignOperator>(syntax)) {
1581     Expr *lhs = stripOpaqueValuesFromPseudoObjectRef(*this, cop->getLHS());
1582     Expr *rhs = cast<OpaqueValueExpr>(cop->getRHS())->getSourceExpr();
1583     return new (Context) CompoundAssignOperator(lhs, rhs, cop->getOpcode(),
1584                                                 cop->getType(),
1585                                                 cop->getValueKind(),
1586                                                 cop->getObjectKind(),
1587                                                 cop->getComputationLHSType(),
1588                                                 cop->getComputationResultType(),
1589                                                 cop->getOperatorLoc(), false);
1590   } else if (BinaryOperator *bop = dyn_cast<BinaryOperator>(syntax)) {
1591     Expr *lhs = stripOpaqueValuesFromPseudoObjectRef(*this, bop->getLHS());
1592     Expr *rhs = cast<OpaqueValueExpr>(bop->getRHS())->getSourceExpr();
1593     return new (Context) BinaryOperator(lhs, rhs, bop->getOpcode(),
1594                                         bop->getType(), bop->getValueKind(),
1595                                         bop->getObjectKind(),
1596                                         bop->getOperatorLoc(), false);
1597   } else {
1598     assert(syntax->hasPlaceholderType(BuiltinType::PseudoObject));
1599     return stripOpaqueValuesFromPseudoObjectRef(*this, syntax);
1600   }
1601 }