SemaPseudoObject.cpp revision 243830 
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/Sema/ScopeInfo.h"
35#include "clang/Sema/Initialization.h"
36#include "clang/AST/ExprObjC.h"
37#include "clang/Lex/Preprocessor.h"
38#include "llvm/ADT/SmallString.h"
39
40using namespace clang;
41using namespace sema;
42
43namespace {
44  // Basically just a very focused copy of TreeTransform.
45  template <class T> struct Rebuilder {
46    Sema &S;
47    Rebuilder(Sema &S) : S(S) {}
48
49    T &getDerived() { return static_cast<T&>(*this); }
50
51    Expr *rebuild(Expr *e) {
52      // Fast path: nothing to look through.
53      if (typename T::specific_type *specific
54            = dyn_cast<typename T::specific_type>(e))
55        return getDerived().rebuildSpecific(specific);
56
57      // Otherwise, we should look through and rebuild anything that
58      // IgnoreParens would.
59
60      if (ParenExpr *parens = dyn_cast<ParenExpr>(e)) {
61        e = rebuild(parens->getSubExpr());
62        return new (S.Context) ParenExpr(parens->getLParen(),
63                                         parens->getRParen(),
64                                         e);
65      }
66
67      if (UnaryOperator *uop = dyn_cast<UnaryOperator>(e)) {
68        assert(uop->getOpcode() == UO_Extension);
69        e = rebuild(uop->getSubExpr());
70        return new (S.Context) UnaryOperator(e, uop->getOpcode(),
71                                             uop->getType(),
72                                             uop->getValueKind(),
73                                             uop->getObjectKind(),
74                                             uop->getOperatorLoc());
75      }
76
77      if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
78        assert(!gse->isResultDependent());
79        unsigned resultIndex = gse->getResultIndex();
80        unsigned numAssocs = gse->getNumAssocs();
81
82        SmallVector<Expr*, 8> assocs(numAssocs);
83        SmallVector<TypeSourceInfo*, 8> assocTypes(numAssocs);
84
85        for (unsigned i = 0; i != numAssocs; ++i) {
86          Expr *assoc = gse->getAssocExpr(i);
87          if (i == resultIndex) assoc = rebuild(assoc);
88          assocs[i] = assoc;
89          assocTypes[i] = gse->getAssocTypeSourceInfo(i);
90        }
91
92        return new (S.Context) GenericSelectionExpr(S.Context,
93                                                    gse->getGenericLoc(),
94                                                    gse->getControllingExpr(),
95                                                    assocTypes,
96                                                    assocs,
97                                                    gse->getDefaultLoc(),
98                                                    gse->getRParenLoc(),
99                                      gse->containsUnexpandedParameterPack(),
100                                                    resultIndex);
101      }
102
103      llvm_unreachable("bad expression to rebuild!");
104    }
105  };
106
107  struct ObjCPropertyRefRebuilder : Rebuilder<ObjCPropertyRefRebuilder> {
108    Expr *NewBase;
109    ObjCPropertyRefRebuilder(Sema &S, Expr *newBase)
110      : Rebuilder<ObjCPropertyRefRebuilder>(S), NewBase(newBase) {}
111
112    typedef ObjCPropertyRefExpr specific_type;
113    Expr *rebuildSpecific(ObjCPropertyRefExpr *refExpr) {
114      // Fortunately, the constraint that we're rebuilding something
115      // with a base limits the number of cases here.
116      assert(refExpr->getBase());
117
118      if (refExpr->isExplicitProperty()) {
119        return new (S.Context)
120          ObjCPropertyRefExpr(refExpr->getExplicitProperty(),
121                              refExpr->getType(), refExpr->getValueKind(),
122                              refExpr->getObjectKind(), refExpr->getLocation(),
123                              NewBase);
124      }
125      return new (S.Context)
126        ObjCPropertyRefExpr(refExpr->getImplicitPropertyGetter(),
127                            refExpr->getImplicitPropertySetter(),
128                            refExpr->getType(), refExpr->getValueKind(),
129                            refExpr->getObjectKind(),refExpr->getLocation(),
130                            NewBase);
131    }
132  };
133
134  struct ObjCSubscriptRefRebuilder : Rebuilder<ObjCSubscriptRefRebuilder> {
135    Expr *NewBase;
136    Expr *NewKeyExpr;
137    ObjCSubscriptRefRebuilder(Sema &S, Expr *newBase, Expr *newKeyExpr)
138    : Rebuilder<ObjCSubscriptRefRebuilder>(S),
139      NewBase(newBase), NewKeyExpr(newKeyExpr) {}
140
141    typedef ObjCSubscriptRefExpr specific_type;
142    Expr *rebuildSpecific(ObjCSubscriptRefExpr *refExpr) {
143      assert(refExpr->getBaseExpr());
144      assert(refExpr->getKeyExpr());
145
146      return new (S.Context)
147        ObjCSubscriptRefExpr(NewBase,
148                             NewKeyExpr,
149                             refExpr->getType(), refExpr->getValueKind(),
150                             refExpr->getObjectKind(),refExpr->getAtIndexMethodDecl(),
151                             refExpr->setAtIndexMethodDecl(),
152                             refExpr->getRBracket());
153    }
154  };
155
156  class PseudoOpBuilder {
157  public:
158    Sema &S;
159    unsigned ResultIndex;
160    SourceLocation GenericLoc;
161    SmallVector<Expr *, 4> Semantics;
162
163    PseudoOpBuilder(Sema &S, SourceLocation genericLoc)
164      : S(S), ResultIndex(PseudoObjectExpr::NoResult),
165        GenericLoc(genericLoc) {}
166
167    virtual ~PseudoOpBuilder() {}
168
169    /// Add a normal semantic expression.
170    void addSemanticExpr(Expr *semantic) {
171      Semantics.push_back(semantic);
172    }
173
174    /// Add the 'result' semantic expression.
175    void addResultSemanticExpr(Expr *resultExpr) {
176      assert(ResultIndex == PseudoObjectExpr::NoResult);
177      ResultIndex = Semantics.size();
178      Semantics.push_back(resultExpr);
179    }
180
181    ExprResult buildRValueOperation(Expr *op);
182    ExprResult buildAssignmentOperation(Scope *Sc,
183                                        SourceLocation opLoc,
184                                        BinaryOperatorKind opcode,
185                                        Expr *LHS, Expr *RHS);
186    ExprResult buildIncDecOperation(Scope *Sc, SourceLocation opLoc,
187                                    UnaryOperatorKind opcode,
188                                    Expr *op);
189
190    virtual ExprResult complete(Expr *syntacticForm);
191
192    OpaqueValueExpr *capture(Expr *op);
193    OpaqueValueExpr *captureValueAsResult(Expr *op);
194
195    void setResultToLastSemantic() {
196      assert(ResultIndex == PseudoObjectExpr::NoResult);
197      ResultIndex = Semantics.size() - 1;
198    }
199
200    /// Return true if assignments have a non-void result.
201    bool CanCaptureValueOfType(QualType ty) {
202      assert(!ty->isIncompleteType());
203      assert(!ty->isDependentType());
204
205      if (const CXXRecordDecl *ClassDecl = ty->getAsCXXRecordDecl())
206        return ClassDecl->isTriviallyCopyable();
207      return true;
208    }
209
210    virtual Expr *rebuildAndCaptureObject(Expr *) = 0;
211    virtual ExprResult buildGet() = 0;
212    virtual ExprResult buildSet(Expr *, SourceLocation,
213                                bool captureSetValueAsResult) = 0;
214  };
215
216  /// A PseudoOpBuilder for Objective-C \@properties.
217  class ObjCPropertyOpBuilder : public PseudoOpBuilder {
218    ObjCPropertyRefExpr *RefExpr;
219    ObjCPropertyRefExpr *SyntacticRefExpr;
220    OpaqueValueExpr *InstanceReceiver;
221    ObjCMethodDecl *Getter;
222
223    ObjCMethodDecl *Setter;
224    Selector SetterSelector;
225    Selector GetterSelector;
226
227  public:
228    ObjCPropertyOpBuilder(Sema &S, ObjCPropertyRefExpr *refExpr) :
229      PseudoOpBuilder(S, refExpr->getLocation()), RefExpr(refExpr),
230      SyntacticRefExpr(0), InstanceReceiver(0), Getter(0), Setter(0) {
231    }
232
233    ExprResult buildRValueOperation(Expr *op);
234    ExprResult buildAssignmentOperation(Scope *Sc,
235                                        SourceLocation opLoc,
236                                        BinaryOperatorKind opcode,
237                                        Expr *LHS, Expr *RHS);
238    ExprResult buildIncDecOperation(Scope *Sc, SourceLocation opLoc,
239                                    UnaryOperatorKind opcode,
240                                    Expr *op);
241
242    bool tryBuildGetOfReference(Expr *op, ExprResult &result);
243    bool findSetter(bool warn=true);
244    bool findGetter();
245
246    Expr *rebuildAndCaptureObject(Expr *syntacticBase);
247    ExprResult buildGet();
248    ExprResult buildSet(Expr *op, SourceLocation, bool);
249    ExprResult complete(Expr *SyntacticForm);
250
251    bool isWeakProperty() const;
252  };
253
254 /// A PseudoOpBuilder for Objective-C array/dictionary indexing.
255 class ObjCSubscriptOpBuilder : public PseudoOpBuilder {
256   ObjCSubscriptRefExpr *RefExpr;
257   OpaqueValueExpr *InstanceBase;
258   OpaqueValueExpr *InstanceKey;
259   ObjCMethodDecl *AtIndexGetter;
260   Selector AtIndexGetterSelector;
261
262   ObjCMethodDecl *AtIndexSetter;
263   Selector AtIndexSetterSelector;
264
265 public:
266    ObjCSubscriptOpBuilder(Sema &S, ObjCSubscriptRefExpr *refExpr) :
267      PseudoOpBuilder(S, refExpr->getSourceRange().getBegin()),
268      RefExpr(refExpr),
269    InstanceBase(0), InstanceKey(0),
270    AtIndexGetter(0), AtIndexSetter(0) { }
271
272   ExprResult buildRValueOperation(Expr *op);
273   ExprResult buildAssignmentOperation(Scope *Sc,
274                                       SourceLocation opLoc,
275                                       BinaryOperatorKind opcode,
276                                       Expr *LHS, Expr *RHS);
277   Expr *rebuildAndCaptureObject(Expr *syntacticBase);
278
279   bool findAtIndexGetter();
280   bool findAtIndexSetter();
281
282   ExprResult buildGet();
283   ExprResult buildSet(Expr *op, SourceLocation, bool);
284 };
285
286}
287
288/// Capture the given expression in an OpaqueValueExpr.
289OpaqueValueExpr *PseudoOpBuilder::capture(Expr *e) {
290  // Make a new OVE whose source is the given expression.
291  OpaqueValueExpr *captured =
292    new (S.Context) OpaqueValueExpr(GenericLoc, e->getType(),
293                                    e->getValueKind(), e->getObjectKind(),
294                                    e);
295
296  // Make sure we bind that in the semantics.
297  addSemanticExpr(captured);
298  return captured;
299}
300
301/// Capture the given expression as the result of this pseudo-object
302/// operation.  This routine is safe against expressions which may
303/// already be captured.
304///
305/// \returns the captured expression, which will be the
306///   same as the input if the input was already captured
307OpaqueValueExpr *PseudoOpBuilder::captureValueAsResult(Expr *e) {
308  assert(ResultIndex == PseudoObjectExpr::NoResult);
309
310  // If the expression hasn't already been captured, just capture it
311  // and set the new semantic
312  if (!isa<OpaqueValueExpr>(e)) {
313    OpaqueValueExpr *cap = capture(e);
314    setResultToLastSemantic();
315    return cap;
316  }
317
318  // Otherwise, it must already be one of our semantic expressions;
319  // set ResultIndex to its index.
320  unsigned index = 0;
321  for (;; ++index) {
322    assert(index < Semantics.size() &&
323           "captured expression not found in semantics!");
324    if (e == Semantics[index]) break;
325  }
326  ResultIndex = index;
327  return cast<OpaqueValueExpr>(e);
328}
329
330/// The routine which creates the final PseudoObjectExpr.
331ExprResult PseudoOpBuilder::complete(Expr *syntactic) {
332  return PseudoObjectExpr::Create(S.Context, syntactic,
333                                  Semantics, ResultIndex);
334}
335
336/// The main skeleton for building an r-value operation.
337ExprResult PseudoOpBuilder::buildRValueOperation(Expr *op) {
338  Expr *syntacticBase = rebuildAndCaptureObject(op);
339
340  ExprResult getExpr = buildGet();
341  if (getExpr.isInvalid()) return ExprError();
342  addResultSemanticExpr(getExpr.take());
343
344  return complete(syntacticBase);
345}
346
347/// The basic skeleton for building a simple or compound
348/// assignment operation.
349ExprResult
350PseudoOpBuilder::buildAssignmentOperation(Scope *Sc, SourceLocation opcLoc,
351                                          BinaryOperatorKind opcode,
352                                          Expr *LHS, Expr *RHS) {
353  assert(BinaryOperator::isAssignmentOp(opcode));
354
355  Expr *syntacticLHS = rebuildAndCaptureObject(LHS);
356  OpaqueValueExpr *capturedRHS = capture(RHS);
357
358  Expr *syntactic;
359
360  ExprResult result;
361  if (opcode == BO_Assign) {
362    result = capturedRHS;
363    syntactic = new (S.Context) BinaryOperator(syntacticLHS, capturedRHS,
364                                               opcode, capturedRHS->getType(),
365                                               capturedRHS->getValueKind(),
366                                               OK_Ordinary, opcLoc, false);
367  } else {
368    ExprResult opLHS = buildGet();
369    if (opLHS.isInvalid()) return ExprError();
370
371    // Build an ordinary, non-compound operation.
372    BinaryOperatorKind nonCompound =
373      BinaryOperator::getOpForCompoundAssignment(opcode);
374    result = S.BuildBinOp(Sc, opcLoc, nonCompound,
375                          opLHS.take(), capturedRHS);
376    if (result.isInvalid()) return ExprError();
377
378    syntactic =
379      new (S.Context) CompoundAssignOperator(syntacticLHS, capturedRHS, opcode,
380                                             result.get()->getType(),
381                                             result.get()->getValueKind(),
382                                             OK_Ordinary,
383                                             opLHS.get()->getType(),
384                                             result.get()->getType(),
385                                             opcLoc, false);
386  }
387
388  // The result of the assignment, if not void, is the value set into
389  // the l-value.
390  result = buildSet(result.take(), opcLoc, /*captureSetValueAsResult*/ true);
391  if (result.isInvalid()) return ExprError();
392  addSemanticExpr(result.take());
393
394  return complete(syntactic);
395}
396
397/// The basic skeleton for building an increment or decrement
398/// operation.
399ExprResult
400PseudoOpBuilder::buildIncDecOperation(Scope *Sc, SourceLocation opcLoc,
401                                      UnaryOperatorKind opcode,
402                                      Expr *op) {
403  assert(UnaryOperator::isIncrementDecrementOp(opcode));
404
405  Expr *syntacticOp = rebuildAndCaptureObject(op);
406
407  // Load the value.
408  ExprResult result = buildGet();
409  if (result.isInvalid()) return ExprError();
410
411  QualType resultType = result.get()->getType();
412
413  // That's the postfix result.
414  if (UnaryOperator::isPostfix(opcode) && CanCaptureValueOfType(resultType)) {
415    result = capture(result.take());
416    setResultToLastSemantic();
417  }
418
419  // Add or subtract a literal 1.
420  llvm::APInt oneV(S.Context.getTypeSize(S.Context.IntTy), 1);
421  Expr *one = IntegerLiteral::Create(S.Context, oneV, S.Context.IntTy,
422                                     GenericLoc);
423
424  if (UnaryOperator::isIncrementOp(opcode)) {
425    result = S.BuildBinOp(Sc, opcLoc, BO_Add, result.take(), one);
426  } else {
427    result = S.BuildBinOp(Sc, opcLoc, BO_Sub, result.take(), one);
428  }
429  if (result.isInvalid()) return ExprError();
430
431  // Store that back into the result.  The value stored is the result
432  // of a prefix operation.
433  result = buildSet(result.take(), opcLoc, UnaryOperator::isPrefix(opcode));
434  if (result.isInvalid()) return ExprError();
435  addSemanticExpr(result.take());
436
437  UnaryOperator *syntactic =
438    new (S.Context) UnaryOperator(syntacticOp, opcode, resultType,
439                                  VK_LValue, OK_Ordinary, opcLoc);
440  return complete(syntactic);
441}
442
443
444//===----------------------------------------------------------------------===//
445//  Objective-C @property and implicit property references
446//===----------------------------------------------------------------------===//
447
448/// Look up a method in the receiver type of an Objective-C property
449/// reference.
450static ObjCMethodDecl *LookupMethodInReceiverType(Sema &S, Selector sel,
451                                            const ObjCPropertyRefExpr *PRE) {
452  if (PRE->isObjectReceiver()) {
453    const ObjCObjectPointerType *PT =
454      PRE->getBase()->getType()->castAs<ObjCObjectPointerType>();
455
456    // Special case for 'self' in class method implementations.
457    if (PT->isObjCClassType() &&
458        S.isSelfExpr(const_cast<Expr*>(PRE->getBase()))) {
459      // This cast is safe because isSelfExpr is only true within
460      // methods.
461      ObjCMethodDecl *method =
462        cast<ObjCMethodDecl>(S.CurContext->getNonClosureAncestor());
463      return S.LookupMethodInObjectType(sel,
464                 S.Context.getObjCInterfaceType(method->getClassInterface()),
465                                        /*instance*/ false);
466    }
467
468    return S.LookupMethodInObjectType(sel, PT->getPointeeType(), true);
469  }
470
471  if (PRE->isSuperReceiver()) {
472    if (const ObjCObjectPointerType *PT =
473        PRE->getSuperReceiverType()->getAs<ObjCObjectPointerType>())
474      return S.LookupMethodInObjectType(sel, PT->getPointeeType(), true);
475
476    return S.LookupMethodInObjectType(sel, PRE->getSuperReceiverType(), false);
477  }
478
479  assert(PRE->isClassReceiver() && "Invalid expression");
480  QualType IT = S.Context.getObjCInterfaceType(PRE->getClassReceiver());
481  return S.LookupMethodInObjectType(sel, IT, false);
482}
483
484bool ObjCPropertyOpBuilder::isWeakProperty() const {
485  QualType T;
486  if (RefExpr->isExplicitProperty()) {
487    const ObjCPropertyDecl *Prop = RefExpr->getExplicitProperty();
488    if (Prop->getPropertyAttributes() & ObjCPropertyDecl::OBJC_PR_weak)
489      return true;
490
491    T = Prop->getType();
492  } else if (Getter) {
493    T = Getter->getResultType();
494  } else {
495    return false;
496  }
497
498  return T.getObjCLifetime() == Qualifiers::OCL_Weak;
499}
500
501bool ObjCPropertyOpBuilder::findGetter() {
502  if (Getter) return true;
503
504  // For implicit properties, just trust the lookup we already did.
505  if (RefExpr->isImplicitProperty()) {
506    if ((Getter = RefExpr->getImplicitPropertyGetter())) {
507      GetterSelector = Getter->getSelector();
508      return true;
509    }
510    else {
511      // Must build the getter selector the hard way.
512      ObjCMethodDecl *setter = RefExpr->getImplicitPropertySetter();
513      assert(setter && "both setter and getter are null - cannot happen");
514      IdentifierInfo *setterName =
515        setter->getSelector().getIdentifierInfoForSlot(0);
516      const char *compStr = setterName->getNameStart();
517      compStr += 3;
518      IdentifierInfo *getterName = &S.Context.Idents.get(compStr);
519      GetterSelector =
520        S.PP.getSelectorTable().getNullarySelector(getterName);
521      return false;
522
523    }
524  }
525
526  ObjCPropertyDecl *prop = RefExpr->getExplicitProperty();
527  Getter = LookupMethodInReceiverType(S, prop->getGetterName(), RefExpr);
528  return (Getter != 0);
529}
530
531/// Try to find the most accurate setter declaration for the property
532/// reference.
533///
534/// \return true if a setter was found, in which case Setter
535bool ObjCPropertyOpBuilder::findSetter(bool warn) {
536  // For implicit properties, just trust the lookup we already did.
537  if (RefExpr->isImplicitProperty()) {
538    if (ObjCMethodDecl *setter = RefExpr->getImplicitPropertySetter()) {
539      Setter = setter;
540      SetterSelector = setter->getSelector();
541      return true;
542    } else {
543      IdentifierInfo *getterName =
544        RefExpr->getImplicitPropertyGetter()->getSelector()
545          .getIdentifierInfoForSlot(0);
546      SetterSelector =
547        SelectorTable::constructSetterName(S.PP.getIdentifierTable(),
548                                           S.PP.getSelectorTable(),
549                                           getterName);
550      return false;
551    }
552  }
553
554  // For explicit properties, this is more involved.
555  ObjCPropertyDecl *prop = RefExpr->getExplicitProperty();
556  SetterSelector = prop->getSetterName();
557
558  // Do a normal method lookup first.
559  if (ObjCMethodDecl *setter =
560        LookupMethodInReceiverType(S, SetterSelector, RefExpr)) {
561    if (setter->isPropertyAccessor() && warn)
562      if (const ObjCInterfaceDecl *IFace =
563          dyn_cast<ObjCInterfaceDecl>(setter->getDeclContext())) {
564        const StringRef thisPropertyName(prop->getName());
565        char front = thisPropertyName.front();
566        front = islower(front) ? toupper(front) : tolower(front);
567        SmallString<100> PropertyName = thisPropertyName;
568        PropertyName[0] = front;
569        IdentifierInfo *AltMember = &S.PP.getIdentifierTable().get(PropertyName);
570        if (ObjCPropertyDecl *prop1 = IFace->FindPropertyDeclaration(AltMember))
571          if (prop != prop1 && (prop1->getSetterMethodDecl() == setter)) {
572            S.Diag(RefExpr->getExprLoc(), diag::error_property_setter_ambiguous_use)
573              << prop->getName() << prop1->getName() << setter->getSelector();
574            S.Diag(prop->getLocation(), diag::note_property_declare);
575            S.Diag(prop1->getLocation(), diag::note_property_declare);
576          }
577      }
578    Setter = setter;
579    return true;
580  }
581
582  // That can fail in the somewhat crazy situation that we're
583  // type-checking a message send within the @interface declaration
584  // that declared the @property.  But it's not clear that that's
585  // valuable to support.
586
587  return false;
588}
589
590/// Capture the base object of an Objective-C property expression.
591Expr *ObjCPropertyOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
592  assert(InstanceReceiver == 0);
593
594  // If we have a base, capture it in an OVE and rebuild the syntactic
595  // form to use the OVE as its base.
596  if (RefExpr->isObjectReceiver()) {
597    InstanceReceiver = capture(RefExpr->getBase());
598
599    syntacticBase =
600      ObjCPropertyRefRebuilder(S, InstanceReceiver).rebuild(syntacticBase);
601  }
602
603  if (ObjCPropertyRefExpr *
604        refE = dyn_cast<ObjCPropertyRefExpr>(syntacticBase->IgnoreParens()))
605    SyntacticRefExpr = refE;
606
607  return syntacticBase;
608}
609
610/// Load from an Objective-C property reference.
611ExprResult ObjCPropertyOpBuilder::buildGet() {
612  findGetter();
613  assert(Getter);
614
615  if (SyntacticRefExpr)
616    SyntacticRefExpr->setIsMessagingGetter();
617
618  QualType receiverType;
619  if (RefExpr->isClassReceiver()) {
620    receiverType = S.Context.getObjCInterfaceType(RefExpr->getClassReceiver());
621  } else if (RefExpr->isSuperReceiver()) {
622    receiverType = RefExpr->getSuperReceiverType();
623  } else {
624    assert(InstanceReceiver);
625    receiverType = InstanceReceiver->getType();
626  }
627
628  // Build a message-send.
629  ExprResult msg;
630  if (Getter->isInstanceMethod() || RefExpr->isObjectReceiver()) {
631    assert(InstanceReceiver || RefExpr->isSuperReceiver());
632    msg = S.BuildInstanceMessageImplicit(InstanceReceiver, receiverType,
633                                         GenericLoc, Getter->getSelector(),
634                                         Getter, MultiExprArg());
635  } else {
636    msg = S.BuildClassMessageImplicit(receiverType, RefExpr->isSuperReceiver(),
637                                      GenericLoc,
638                                      Getter->getSelector(), Getter,
639                                      MultiExprArg());
640  }
641  return msg;
642}
643
644/// Store to an Objective-C property reference.
645///
646/// \param captureSetValueAsResult If true, capture the actual
647///   value being set as the value of the property operation.
648ExprResult ObjCPropertyOpBuilder::buildSet(Expr *op, SourceLocation opcLoc,
649                                           bool captureSetValueAsResult) {
650  bool hasSetter = findSetter(false);
651  assert(hasSetter); (void) hasSetter;
652
653  if (SyntacticRefExpr)
654    SyntacticRefExpr->setIsMessagingSetter();
655
656  QualType receiverType;
657  if (RefExpr->isClassReceiver()) {
658    receiverType = S.Context.getObjCInterfaceType(RefExpr->getClassReceiver());
659  } else if (RefExpr->isSuperReceiver()) {
660    receiverType = RefExpr->getSuperReceiverType();
661  } else {
662    assert(InstanceReceiver);
663    receiverType = InstanceReceiver->getType();
664  }
665
666  // Use assignment constraints when possible; they give us better
667  // diagnostics.  "When possible" basically means anything except a
668  // C++ class type.
669  if (!S.getLangOpts().CPlusPlus || !op->getType()->isRecordType()) {
670    QualType paramType = (*Setter->param_begin())->getType();
671    if (!S.getLangOpts().CPlusPlus || !paramType->isRecordType()) {
672      ExprResult opResult = op;
673      Sema::AssignConvertType assignResult
674        = S.CheckSingleAssignmentConstraints(paramType, opResult);
675      if (S.DiagnoseAssignmentResult(assignResult, opcLoc, paramType,
676                                     op->getType(), opResult.get(),
677                                     Sema::AA_Assigning))
678        return ExprError();
679
680      op = opResult.take();
681      assert(op && "successful assignment left argument invalid?");
682    }
683  }
684
685  // Arguments.
686  Expr *args[] = { op };
687
688  // Build a message-send.
689  ExprResult msg;
690  if (Setter->isInstanceMethod() || RefExpr->isObjectReceiver()) {
691    msg = S.BuildInstanceMessageImplicit(InstanceReceiver, receiverType,
692                                         GenericLoc, SetterSelector, Setter,
693                                         MultiExprArg(args, 1));
694  } else {
695    msg = S.BuildClassMessageImplicit(receiverType, RefExpr->isSuperReceiver(),
696                                      GenericLoc,
697                                      SetterSelector, Setter,
698                                      MultiExprArg(args, 1));
699  }
700
701  if (!msg.isInvalid() && captureSetValueAsResult) {
702    ObjCMessageExpr *msgExpr =
703      cast<ObjCMessageExpr>(msg.get()->IgnoreImplicit());
704    Expr *arg = msgExpr->getArg(0);
705    if (CanCaptureValueOfType(arg->getType()))
706      msgExpr->setArg(0, captureValueAsResult(arg));
707  }
708
709  return msg;
710}
711
712/// @property-specific behavior for doing lvalue-to-rvalue conversion.
713ExprResult ObjCPropertyOpBuilder::buildRValueOperation(Expr *op) {
714  // Explicit properties always have getters, but implicit ones don't.
715  // Check that before proceeding.
716  if (RefExpr->isImplicitProperty() &&
717      !RefExpr->getImplicitPropertyGetter()) {
718    S.Diag(RefExpr->getLocation(), diag::err_getter_not_found)
719      << RefExpr->getBase()->getType();
720    return ExprError();
721  }
722
723  ExprResult result = PseudoOpBuilder::buildRValueOperation(op);
724  if (result.isInvalid()) return ExprError();
725
726  if (RefExpr->isExplicitProperty() && !Getter->hasRelatedResultType())
727    S.DiagnosePropertyAccessorMismatch(RefExpr->getExplicitProperty(),
728                                       Getter, RefExpr->getLocation());
729
730  // As a special case, if the method returns 'id', try to get
731  // a better type from the property.
732  if (RefExpr->isExplicitProperty() && result.get()->isRValue() &&
733      result.get()->getType()->isObjCIdType()) {
734    QualType propType = RefExpr->getExplicitProperty()->getType();
735    if (const ObjCObjectPointerType *ptr
736          = propType->getAs<ObjCObjectPointerType>()) {
737      if (!ptr->isObjCIdType())
738        result = S.ImpCastExprToType(result.get(), propType, CK_BitCast);
739    }
740  }
741
742  return result;
743}
744
745/// Try to build this as a call to a getter that returns a reference.
746///
747/// \return true if it was possible, whether or not it actually
748///   succeeded
749bool ObjCPropertyOpBuilder::tryBuildGetOfReference(Expr *op,
750                                                   ExprResult &result) {
751  if (!S.getLangOpts().CPlusPlus) return false;
752
753  findGetter();
754  assert(Getter && "property has no setter and no getter!");
755
756  // Only do this if the getter returns an l-value reference type.
757  QualType resultType = Getter->getResultType();
758  if (!resultType->isLValueReferenceType()) return false;
759
760  result = buildRValueOperation(op);
761  return true;
762}
763
764/// @property-specific behavior for doing assignments.
765ExprResult
766ObjCPropertyOpBuilder::buildAssignmentOperation(Scope *Sc,
767                                                SourceLocation opcLoc,
768                                                BinaryOperatorKind opcode,
769                                                Expr *LHS, Expr *RHS) {
770  assert(BinaryOperator::isAssignmentOp(opcode));
771
772  // If there's no setter, we have no choice but to try to assign to
773  // the result of the getter.
774  if (!findSetter()) {
775    ExprResult result;
776    if (tryBuildGetOfReference(LHS, result)) {
777      if (result.isInvalid()) return ExprError();
778      return S.BuildBinOp(Sc, opcLoc, opcode, result.take(), RHS);
779    }
780
781    // Otherwise, it's an error.
782    S.Diag(opcLoc, diag::err_nosetter_property_assignment)
783      << unsigned(RefExpr->isImplicitProperty())
784      << SetterSelector
785      << LHS->getSourceRange() << RHS->getSourceRange();
786    return ExprError();
787  }
788
789  // If there is a setter, we definitely want to use it.
790
791  // Verify that we can do a compound assignment.
792  if (opcode != BO_Assign && !findGetter()) {
793    S.Diag(opcLoc, diag::err_nogetter_property_compound_assignment)
794      << LHS->getSourceRange() << RHS->getSourceRange();
795    return ExprError();
796  }
797
798  ExprResult result =
799    PseudoOpBuilder::buildAssignmentOperation(Sc, opcLoc, opcode, LHS, RHS);
800  if (result.isInvalid()) return ExprError();
801
802  // Various warnings about property assignments in ARC.
803  if (S.getLangOpts().ObjCAutoRefCount && InstanceReceiver) {
804    S.checkRetainCycles(InstanceReceiver->getSourceExpr(), RHS);
805    S.checkUnsafeExprAssigns(opcLoc, LHS, RHS);
806  }
807
808  return result;
809}
810
811/// @property-specific behavior for doing increments and decrements.
812ExprResult
813ObjCPropertyOpBuilder::buildIncDecOperation(Scope *Sc, SourceLocation opcLoc,
814                                            UnaryOperatorKind opcode,
815                                            Expr *op) {
816  // If there's no setter, we have no choice but to try to assign to
817  // the result of the getter.
818  if (!findSetter()) {
819    ExprResult result;
820    if (tryBuildGetOfReference(op, result)) {
821      if (result.isInvalid()) return ExprError();
822      return S.BuildUnaryOp(Sc, opcLoc, opcode, result.take());
823    }
824
825    // Otherwise, it's an error.
826    S.Diag(opcLoc, diag::err_nosetter_property_incdec)
827      << unsigned(RefExpr->isImplicitProperty())
828      << unsigned(UnaryOperator::isDecrementOp(opcode))
829      << SetterSelector
830      << op->getSourceRange();
831    return ExprError();
832  }
833
834  // If there is a setter, we definitely want to use it.
835
836  // We also need a getter.
837  if (!findGetter()) {
838    assert(RefExpr->isImplicitProperty());
839    S.Diag(opcLoc, diag::err_nogetter_property_incdec)
840      << unsigned(UnaryOperator::isDecrementOp(opcode))
841      << GetterSelector
842      << op->getSourceRange();
843    return ExprError();
844  }
845
846  return PseudoOpBuilder::buildIncDecOperation(Sc, opcLoc, opcode, op);
847}
848
849ExprResult ObjCPropertyOpBuilder::complete(Expr *SyntacticForm) {
850  if (S.getLangOpts().ObjCAutoRefCount && isWeakProperty()) {
851    DiagnosticsEngine::Level Level =
852      S.Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak,
853                                 SyntacticForm->getLocStart());
854    if (Level != DiagnosticsEngine::Ignored)
855      S.getCurFunction()->recordUseOfWeak(SyntacticRefExpr,
856                                         SyntacticRefExpr->isMessagingGetter());
857  }
858
859  return PseudoOpBuilder::complete(SyntacticForm);
860}
861
862// ObjCSubscript build stuff.
863//
864
865/// objective-c subscripting-specific behavior for doing lvalue-to-rvalue
866/// conversion.
867/// FIXME. Remove this routine if it is proven that no additional
868/// specifity is needed.
869ExprResult ObjCSubscriptOpBuilder::buildRValueOperation(Expr *op) {
870  ExprResult result = PseudoOpBuilder::buildRValueOperation(op);
871  if (result.isInvalid()) return ExprError();
872  return result;
873}
874
875/// objective-c subscripting-specific  behavior for doing assignments.
876ExprResult
877ObjCSubscriptOpBuilder::buildAssignmentOperation(Scope *Sc,
878                                                SourceLocation opcLoc,
879                                                BinaryOperatorKind opcode,
880                                                Expr *LHS, Expr *RHS) {
881  assert(BinaryOperator::isAssignmentOp(opcode));
882  // There must be a method to do the Index'ed assignment.
883  if (!findAtIndexSetter())
884    return ExprError();
885
886  // Verify that we can do a compound assignment.
887  if (opcode != BO_Assign && !findAtIndexGetter())
888    return ExprError();
889
890  ExprResult result =
891  PseudoOpBuilder::buildAssignmentOperation(Sc, opcLoc, opcode, LHS, RHS);
892  if (result.isInvalid()) return ExprError();
893
894  // Various warnings about objc Index'ed assignments in ARC.
895  if (S.getLangOpts().ObjCAutoRefCount && InstanceBase) {
896    S.checkRetainCycles(InstanceBase->getSourceExpr(), RHS);
897    S.checkUnsafeExprAssigns(opcLoc, LHS, RHS);
898  }
899
900  return result;
901}
902
903/// Capture the base object of an Objective-C Index'ed expression.
904Expr *ObjCSubscriptOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
905  assert(InstanceBase == 0);
906
907  // Capture base expression in an OVE and rebuild the syntactic
908  // form to use the OVE as its base expression.
909  InstanceBase = capture(RefExpr->getBaseExpr());
910  InstanceKey = capture(RefExpr->getKeyExpr());
911
912  syntacticBase =
913    ObjCSubscriptRefRebuilder(S, InstanceBase,
914                              InstanceKey).rebuild(syntacticBase);
915
916  return syntacticBase;
917}
918
919/// CheckSubscriptingKind - This routine decide what type
920/// of indexing represented by "FromE" is being done.
921Sema::ObjCSubscriptKind
922  Sema::CheckSubscriptingKind(Expr *FromE) {
923  // If the expression already has integral or enumeration type, we're golden.
924  QualType T = FromE->getType();
925  if (T->isIntegralOrEnumerationType())
926    return OS_Array;
927
928  // If we don't have a class type in C++, there's no way we can get an
929  // expression of integral or enumeration type.
930  const RecordType *RecordTy = T->getAs<RecordType>();
931  if (!RecordTy && T->isObjCObjectPointerType())
932    // All other scalar cases are assumed to be dictionary indexing which
933    // caller handles, with diagnostics if needed.
934    return OS_Dictionary;
935  if (!getLangOpts().CPlusPlus ||
936      !RecordTy || RecordTy->isIncompleteType()) {
937    // No indexing can be done. Issue diagnostics and quit.
938    const Expr *IndexExpr = FromE->IgnoreParenImpCasts();
939    if (isa<StringLiteral>(IndexExpr))
940      Diag(FromE->getExprLoc(), diag::err_objc_subscript_pointer)
941        << T << FixItHint::CreateInsertion(FromE->getExprLoc(), "@");
942    else
943      Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
944        << T;
945    return OS_Error;
946  }
947
948  // We must have a complete class type.
949  if (RequireCompleteType(FromE->getExprLoc(), T,
950                          diag::err_objc_index_incomplete_class_type, FromE))
951    return OS_Error;
952
953  // Look for a conversion to an integral, enumeration type, or
954  // objective-C pointer type.
955  UnresolvedSet<4> ViableConversions;
956  UnresolvedSet<4> ExplicitConversions;
957  const UnresolvedSetImpl *Conversions
958    = cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();
959
960  int NoIntegrals=0, NoObjCIdPointers=0;
961  SmallVector<CXXConversionDecl *, 4> ConversionDecls;
962
963  for (UnresolvedSetImpl::iterator I = Conversions->begin(),
964       E = Conversions->end();
965       I != E;
966       ++I) {
967    if (CXXConversionDecl *Conversion
968        = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) {
969      QualType CT = Conversion->getConversionType().getNonReferenceType();
970      if (CT->isIntegralOrEnumerationType()) {
971        ++NoIntegrals;
972        ConversionDecls.push_back(Conversion);
973      }
974      else if (CT->isObjCIdType() ||CT->isBlockPointerType()) {
975        ++NoObjCIdPointers;
976        ConversionDecls.push_back(Conversion);
977      }
978    }
979  }
980  if (NoIntegrals ==1 && NoObjCIdPointers == 0)
981    return OS_Array;
982  if (NoIntegrals == 0 && NoObjCIdPointers == 1)
983    return OS_Dictionary;
984  if (NoIntegrals == 0 && NoObjCIdPointers == 0) {
985    // No conversion function was found. Issue diagnostic and return.
986    Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
987      << FromE->getType();
988    return OS_Error;
989  }
990  Diag(FromE->getExprLoc(), diag::err_objc_multiple_subscript_type_conversion)
991      << FromE->getType();
992  for (unsigned int i = 0; i < ConversionDecls.size(); i++)
993    Diag(ConversionDecls[i]->getLocation(), diag::not_conv_function_declared_at);
994
995  return OS_Error;
996}
997
998/// CheckKeyForObjCARCConversion - This routine suggests bridge casting of CF
999/// objects used as dictionary subscript key objects.
1000static void CheckKeyForObjCARCConversion(Sema &S, QualType ContainerT,
1001                                         Expr *Key) {
1002  if (ContainerT.isNull())
1003    return;
1004  // dictionary subscripting.
1005  // - (id)objectForKeyedSubscript:(id)key;
1006  IdentifierInfo *KeyIdents[] = {
1007    &S.Context.Idents.get("objectForKeyedSubscript")
1008  };
1009  Selector GetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
1010  ObjCMethodDecl *Getter = S.LookupMethodInObjectType(GetterSelector, ContainerT,
1011                                                      true /*instance*/);
1012  if (!Getter)
1013    return;
1014  QualType T = Getter->param_begin()[0]->getType();
1015  S.CheckObjCARCConversion(Key->getSourceRange(),
1016                         T, Key, Sema::CCK_ImplicitConversion);
1017}
1018
1019bool ObjCSubscriptOpBuilder::findAtIndexGetter() {
1020  if (AtIndexGetter)
1021    return true;
1022
1023  Expr *BaseExpr = RefExpr->getBaseExpr();
1024  QualType BaseT = BaseExpr->getType();
1025
1026  QualType ResultType;
1027  if (const ObjCObjectPointerType *PTy =
1028      BaseT->getAs<ObjCObjectPointerType>()) {
1029    ResultType = PTy->getPointeeType();
1030    if (const ObjCObjectType *iQFaceTy =
1031        ResultType->getAsObjCQualifiedInterfaceType())
1032      ResultType = iQFaceTy->getBaseType();
1033  }
1034  Sema::ObjCSubscriptKind Res =
1035    S.CheckSubscriptingKind(RefExpr->getKeyExpr());
1036  if (Res == Sema::OS_Error) {
1037    if (S.getLangOpts().ObjCAutoRefCount)
1038      CheckKeyForObjCARCConversion(S, ResultType,
1039                                   RefExpr->getKeyExpr());
1040    return false;
1041  }
1042  bool arrayRef = (Res == Sema::OS_Array);
1043
1044  if (ResultType.isNull()) {
1045    S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
1046      << BaseExpr->getType() << arrayRef;
1047    return false;
1048  }
1049  if (!arrayRef) {
1050    // dictionary subscripting.
1051    // - (id)objectForKeyedSubscript:(id)key;
1052    IdentifierInfo *KeyIdents[] = {
1053      &S.Context.Idents.get("objectForKeyedSubscript")
1054    };
1055    AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
1056  }
1057  else {
1058    // - (id)objectAtIndexedSubscript:(size_t)index;
1059    IdentifierInfo *KeyIdents[] = {
1060      &S.Context.Idents.get("objectAtIndexedSubscript")
1061    };
1062
1063    AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
1064  }
1065
1066  AtIndexGetter = S.LookupMethodInObjectType(AtIndexGetterSelector, ResultType,
1067                                             true /*instance*/);
1068  bool receiverIdType = (BaseT->isObjCIdType() ||
1069                         BaseT->isObjCQualifiedIdType());
1070
1071  if (!AtIndexGetter && S.getLangOpts().DebuggerObjCLiteral) {
1072    AtIndexGetter = ObjCMethodDecl::Create(S.Context, SourceLocation(),
1073                           SourceLocation(), AtIndexGetterSelector,
1074                           S.Context.getObjCIdType() /*ReturnType*/,
1075                           0 /*TypeSourceInfo */,
1076                           S.Context.getTranslationUnitDecl(),
1077                           true /*Instance*/, false/*isVariadic*/,
1078                           /*isPropertyAccessor=*/false,
1079                           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
1080                           ObjCMethodDecl::Required,
1081                           false);
1082    ParmVarDecl *Argument = ParmVarDecl::Create(S.Context, AtIndexGetter,
1083                                                SourceLocation(), SourceLocation(),
1084                                                arrayRef ? &S.Context.Idents.get("index")
1085                                                         : &S.Context.Idents.get("key"),
1086                                                arrayRef ? S.Context.UnsignedLongTy
1087                                                         : S.Context.getObjCIdType(),
1088                                                /*TInfo=*/0,
1089                                                SC_None,
1090                                                SC_None,
1091                                                0);
1092    AtIndexGetter->setMethodParams(S.Context, Argument,
1093                                   ArrayRef<SourceLocation>());
1094  }
1095
1096  if (!AtIndexGetter) {
1097    if (!receiverIdType) {
1098      S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_method_not_found)
1099      << BaseExpr->getType() << 0 << arrayRef;
1100      return false;
1101    }
1102    AtIndexGetter =
1103      S.LookupInstanceMethodInGlobalPool(AtIndexGetterSelector,
1104                                         RefExpr->getSourceRange(),
1105                                         true, false);
1106  }
1107
1108  if (AtIndexGetter) {
1109    QualType T = AtIndexGetter->param_begin()[0]->getType();
1110    if ((arrayRef && !T->isIntegralOrEnumerationType()) ||
1111        (!arrayRef && !T->isObjCObjectPointerType())) {
1112      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1113             arrayRef ? diag::err_objc_subscript_index_type
1114                      : diag::err_objc_subscript_key_type) << T;
1115      S.Diag(AtIndexGetter->param_begin()[0]->getLocation(),
1116             diag::note_parameter_type) << T;
1117      return false;
1118    }
1119    QualType R = AtIndexGetter->getResultType();
1120    if (!R->isObjCObjectPointerType()) {
1121      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1122             diag::err_objc_indexing_method_result_type) << R << arrayRef;
1123      S.Diag(AtIndexGetter->getLocation(), diag::note_method_declared_at) <<
1124        AtIndexGetter->getDeclName();
1125    }
1126  }
1127  return true;
1128}
1129
1130bool ObjCSubscriptOpBuilder::findAtIndexSetter() {
1131  if (AtIndexSetter)
1132    return true;
1133
1134  Expr *BaseExpr = RefExpr->getBaseExpr();
1135  QualType BaseT = BaseExpr->getType();
1136
1137  QualType ResultType;
1138  if (const ObjCObjectPointerType *PTy =
1139      BaseT->getAs<ObjCObjectPointerType>()) {
1140    ResultType = PTy->getPointeeType();
1141    if (const ObjCObjectType *iQFaceTy =
1142        ResultType->getAsObjCQualifiedInterfaceType())
1143      ResultType = iQFaceTy->getBaseType();
1144  }
1145
1146  Sema::ObjCSubscriptKind Res =
1147    S.CheckSubscriptingKind(RefExpr->getKeyExpr());
1148  if (Res == Sema::OS_Error) {
1149    if (S.getLangOpts().ObjCAutoRefCount)
1150      CheckKeyForObjCARCConversion(S, ResultType,
1151                                   RefExpr->getKeyExpr());
1152    return false;
1153  }
1154  bool arrayRef = (Res == Sema::OS_Array);
1155
1156  if (ResultType.isNull()) {
1157    S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
1158      << BaseExpr->getType() << arrayRef;
1159    return false;
1160  }
1161
1162  if (!arrayRef) {
1163    // dictionary subscripting.
1164    // - (void)setObject:(id)object forKeyedSubscript:(id)key;
1165    IdentifierInfo *KeyIdents[] = {
1166      &S.Context.Idents.get("setObject"),
1167      &S.Context.Idents.get("forKeyedSubscript")
1168    };
1169    AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
1170  }
1171  else {
1172    // - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
1173    IdentifierInfo *KeyIdents[] = {
1174      &S.Context.Idents.get("setObject"),
1175      &S.Context.Idents.get("atIndexedSubscript")
1176    };
1177    AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
1178  }
1179  AtIndexSetter = S.LookupMethodInObjectType(AtIndexSetterSelector, ResultType,
1180                                             true /*instance*/);
1181
1182  bool receiverIdType = (BaseT->isObjCIdType() ||
1183                         BaseT->isObjCQualifiedIdType());
1184
1185  if (!AtIndexSetter && S.getLangOpts().DebuggerObjCLiteral) {
1186    TypeSourceInfo *ResultTInfo = 0;
1187    QualType ReturnType = S.Context.VoidTy;
1188    AtIndexSetter = ObjCMethodDecl::Create(S.Context, SourceLocation(),
1189                           SourceLocation(), AtIndexSetterSelector,
1190                           ReturnType,
1191                           ResultTInfo,
1192                           S.Context.getTranslationUnitDecl(),
1193                           true /*Instance*/, false/*isVariadic*/,
1194                           /*isPropertyAccessor=*/false,
1195                           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
1196                           ObjCMethodDecl::Required,
1197                           false);
1198    SmallVector<ParmVarDecl *, 2> Params;
1199    ParmVarDecl *object = ParmVarDecl::Create(S.Context, AtIndexSetter,
1200                                                SourceLocation(), SourceLocation(),
1201                                                &S.Context.Idents.get("object"),
1202                                                S.Context.getObjCIdType(),
1203                                                /*TInfo=*/0,
1204                                                SC_None,
1205                                                SC_None,
1206                                                0);
1207    Params.push_back(object);
1208    ParmVarDecl *key = ParmVarDecl::Create(S.Context, AtIndexSetter,
1209                                                SourceLocation(), SourceLocation(),
1210                                                arrayRef ?  &S.Context.Idents.get("index")
1211                                                         :  &S.Context.Idents.get("key"),
1212                                                arrayRef ? S.Context.UnsignedLongTy
1213                                                         : S.Context.getObjCIdType(),
1214                                                /*TInfo=*/0,
1215                                                SC_None,
1216                                                SC_None,
1217                                                0);
1218    Params.push_back(key);
1219    AtIndexSetter->setMethodParams(S.Context, Params, ArrayRef<SourceLocation>());
1220  }
1221
1222  if (!AtIndexSetter) {
1223    if (!receiverIdType) {
1224      S.Diag(BaseExpr->getExprLoc(),
1225             diag::err_objc_subscript_method_not_found)
1226      << BaseExpr->getType() << 1 << arrayRef;
1227      return false;
1228    }
1229    AtIndexSetter =
1230      S.LookupInstanceMethodInGlobalPool(AtIndexSetterSelector,
1231                                         RefExpr->getSourceRange(),
1232                                         true, false);
1233  }
1234
1235  bool err = false;
1236  if (AtIndexSetter && arrayRef) {
1237    QualType T = AtIndexSetter->param_begin()[1]->getType();
1238    if (!T->isIntegralOrEnumerationType()) {
1239      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1240             diag::err_objc_subscript_index_type) << T;
1241      S.Diag(AtIndexSetter->param_begin()[1]->getLocation(),
1242             diag::note_parameter_type) << T;
1243      err = true;
1244    }
1245    T = AtIndexSetter->param_begin()[0]->getType();
1246    if (!T->isObjCObjectPointerType()) {
1247      S.Diag(RefExpr->getBaseExpr()->getExprLoc(),
1248             diag::err_objc_subscript_object_type) << T << arrayRef;
1249      S.Diag(AtIndexSetter->param_begin()[0]->getLocation(),
1250             diag::note_parameter_type) << T;
1251      err = true;
1252    }
1253  }
1254  else if (AtIndexSetter && !arrayRef)
1255    for (unsigned i=0; i <2; i++) {
1256      QualType T = AtIndexSetter->param_begin()[i]->getType();
1257      if (!T->isObjCObjectPointerType()) {
1258        if (i == 1)
1259          S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1260                 diag::err_objc_subscript_key_type) << T;
1261        else
1262          S.Diag(RefExpr->getBaseExpr()->getExprLoc(),
1263                 diag::err_objc_subscript_dic_object_type) << T;
1264        S.Diag(AtIndexSetter->param_begin()[i]->getLocation(),
1265               diag::note_parameter_type) << T;
1266        err = true;
1267      }
1268    }
1269
1270  return !err;
1271}
1272
1273// Get the object at "Index" position in the container.
1274// [BaseExpr objectAtIndexedSubscript : IndexExpr];
1275ExprResult ObjCSubscriptOpBuilder::buildGet() {
1276  if (!findAtIndexGetter())
1277    return ExprError();
1278
1279  QualType receiverType = InstanceBase->getType();
1280
1281  // Build a message-send.
1282  ExprResult msg;
1283  Expr *Index = InstanceKey;
1284
1285  // Arguments.
1286  Expr *args[] = { Index };
1287  assert(InstanceBase);
1288  msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
1289                                       GenericLoc,
1290                                       AtIndexGetterSelector, AtIndexGetter,
1291                                       MultiExprArg(args, 1));
1292  return msg;
1293}
1294
1295/// Store into the container the "op" object at "Index"'ed location
1296/// by building this messaging expression:
1297/// - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
1298/// \param captureSetValueAsResult If true, capture the actual
1299///   value being set as the value of the property operation.
1300ExprResult ObjCSubscriptOpBuilder::buildSet(Expr *op, SourceLocation opcLoc,
1301                                           bool captureSetValueAsResult) {
1302  if (!findAtIndexSetter())
1303    return ExprError();
1304
1305  QualType receiverType = InstanceBase->getType();
1306  Expr *Index = InstanceKey;
1307
1308  // Arguments.
1309  Expr *args[] = { op, Index };
1310
1311  // Build a message-send.
1312  ExprResult msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
1313                                                  GenericLoc,
1314                                                  AtIndexSetterSelector,
1315                                                  AtIndexSetter,
1316                                                  MultiExprArg(args, 2));
1317
1318  if (!msg.isInvalid() && captureSetValueAsResult) {
1319    ObjCMessageExpr *msgExpr =
1320      cast<ObjCMessageExpr>(msg.get()->IgnoreImplicit());
1321    Expr *arg = msgExpr->getArg(0);
1322    if (CanCaptureValueOfType(arg->getType()))
1323      msgExpr->setArg(0, captureValueAsResult(arg));
1324  }
1325
1326  return msg;
1327}
1328
1329//===----------------------------------------------------------------------===//
1330//  General Sema routines.
1331//===----------------------------------------------------------------------===//
1332
1333ExprResult Sema::checkPseudoObjectRValue(Expr *E) {
1334  Expr *opaqueRef = E->IgnoreParens();
1335  if (ObjCPropertyRefExpr *refExpr
1336        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1337    ObjCPropertyOpBuilder builder(*this, refExpr);
1338    return builder.buildRValueOperation(E);
1339  }
1340  else if (ObjCSubscriptRefExpr *refExpr
1341           = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1342    ObjCSubscriptOpBuilder builder(*this, refExpr);
1343    return builder.buildRValueOperation(E);
1344  } else {
1345    llvm_unreachable("unknown pseudo-object kind!");
1346  }
1347}
1348
1349/// Check an increment or decrement of a pseudo-object expression.
1350ExprResult Sema::checkPseudoObjectIncDec(Scope *Sc, SourceLocation opcLoc,
1351                                         UnaryOperatorKind opcode, Expr *op) {
1352  // Do nothing if the operand is dependent.
1353  if (op->isTypeDependent())
1354    return new (Context) UnaryOperator(op, opcode, Context.DependentTy,
1355                                       VK_RValue, OK_Ordinary, opcLoc);
1356
1357  assert(UnaryOperator::isIncrementDecrementOp(opcode));
1358  Expr *opaqueRef = op->IgnoreParens();
1359  if (ObjCPropertyRefExpr *refExpr
1360        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1361    ObjCPropertyOpBuilder builder(*this, refExpr);
1362    return builder.buildIncDecOperation(Sc, opcLoc, opcode, op);
1363  } else if (isa<ObjCSubscriptRefExpr>(opaqueRef)) {
1364    Diag(opcLoc, diag::err_illegal_container_subscripting_op);
1365    return ExprError();
1366  } else {
1367    llvm_unreachable("unknown pseudo-object kind!");
1368  }
1369}
1370
1371ExprResult Sema::checkPseudoObjectAssignment(Scope *S, SourceLocation opcLoc,
1372                                             BinaryOperatorKind opcode,
1373                                             Expr *LHS, Expr *RHS) {
1374  // Do nothing if either argument is dependent.
1375  if (LHS->isTypeDependent() || RHS->isTypeDependent())
1376    return new (Context) BinaryOperator(LHS, RHS, opcode, Context.DependentTy,
1377                                        VK_RValue, OK_Ordinary, opcLoc, false);
1378
1379  // Filter out non-overload placeholder types in the RHS.
1380  if (RHS->getType()->isNonOverloadPlaceholderType()) {
1381    ExprResult result = CheckPlaceholderExpr(RHS);
1382    if (result.isInvalid()) return ExprError();
1383    RHS = result.take();
1384  }
1385
1386  Expr *opaqueRef = LHS->IgnoreParens();
1387  if (ObjCPropertyRefExpr *refExpr
1388        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1389    ObjCPropertyOpBuilder builder(*this, refExpr);
1390    return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
1391  } else if (ObjCSubscriptRefExpr *refExpr
1392             = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1393    ObjCSubscriptOpBuilder builder(*this, refExpr);
1394    return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
1395  } else {
1396    llvm_unreachable("unknown pseudo-object kind!");
1397  }
1398}
1399
1400/// Given a pseudo-object reference, rebuild it without the opaque
1401/// values.  Basically, undo the behavior of rebuildAndCaptureObject.
1402/// This should never operate in-place.
1403static Expr *stripOpaqueValuesFromPseudoObjectRef(Sema &S, Expr *E) {
1404  Expr *opaqueRef = E->IgnoreParens();
1405  if (ObjCPropertyRefExpr *refExpr
1406        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1407    // Class and super property references don't have opaque values in them.
1408    if (refExpr->isClassReceiver() || refExpr->isSuperReceiver())
1409      return E;
1410
1411    assert(refExpr->isObjectReceiver() && "Unknown receiver kind?");
1412    OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBase());
1413    return ObjCPropertyRefRebuilder(S, baseOVE->getSourceExpr()).rebuild(E);
1414  } else if (ObjCSubscriptRefExpr *refExpr
1415               = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1416    OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBaseExpr());
1417    OpaqueValueExpr *keyOVE = cast<OpaqueValueExpr>(refExpr->getKeyExpr());
1418    return ObjCSubscriptRefRebuilder(S, baseOVE->getSourceExpr(),
1419                                     keyOVE->getSourceExpr()).rebuild(E);
1420  } else {
1421    llvm_unreachable("unknown pseudo-object kind!");
1422  }
1423}
1424
1425/// Given a pseudo-object expression, recreate what it looks like
1426/// syntactically without the attendant OpaqueValueExprs.
1427///
1428/// This is a hack which should be removed when TreeTransform is
1429/// capable of rebuilding a tree without stripping implicit
1430/// operations.
1431Expr *Sema::recreateSyntacticForm(PseudoObjectExpr *E) {
1432  Expr *syntax = E->getSyntacticForm();
1433  if (UnaryOperator *uop = dyn_cast<UnaryOperator>(syntax)) {
1434    Expr *op = stripOpaqueValuesFromPseudoObjectRef(*this, uop->getSubExpr());
1435    return new (Context) UnaryOperator(op, uop->getOpcode(), uop->getType(),
1436                                       uop->getValueKind(), uop->getObjectKind(),
1437                                       uop->getOperatorLoc());
1438  } else if (CompoundAssignOperator *cop
1439               = dyn_cast<CompoundAssignOperator>(syntax)) {
1440    Expr *lhs = stripOpaqueValuesFromPseudoObjectRef(*this, cop->getLHS());
1441    Expr *rhs = cast<OpaqueValueExpr>(cop->getRHS())->getSourceExpr();
1442    return new (Context) CompoundAssignOperator(lhs, rhs, cop->getOpcode(),
1443                                                cop->getType(),
1444                                                cop->getValueKind(),
1445                                                cop->getObjectKind(),
1446                                                cop->getComputationLHSType(),
1447                                                cop->getComputationResultType(),
1448                                                cop->getOperatorLoc(), false);
1449  } else if (BinaryOperator *bop = dyn_cast<BinaryOperator>(syntax)) {
1450    Expr *lhs = stripOpaqueValuesFromPseudoObjectRef(*this, bop->getLHS());
1451    Expr *rhs = cast<OpaqueValueExpr>(bop->getRHS())->getSourceExpr();
1452    return new (Context) BinaryOperator(lhs, rhs, bop->getOpcode(),
1453                                        bop->getType(), bop->getValueKind(),
1454                                        bop->getObjectKind(),
1455                                        bop->getOperatorLoc(), false);
1456  } else {
1457    assert(syntax->hasPlaceholderType(BuiltinType::PseudoObject));
1458    return stripOpaqueValuesFromPseudoObjectRef(*this, syntax);
1459  }
1460}
1461