SemaPseudoObject.cpp revision cba0ebce65667f76e291346d377f402579743cea 
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/Initialization.h"
35#include "clang/AST/ExprObjC.h"
36#include "clang/Lex/Preprocessor.h"
37#include "llvm/ADT/SmallString.h"
38
39using namespace clang;
40using namespace sema;
41
42namespace {
43  // Basically just a very focused copy of TreeTransform.
44  template <class T> struct Rebuilder {
45    Sema &S;
46    Rebuilder(Sema &S) : S(S) {}
47
48    T &getDerived() { return static_cast<T&>(*this); }
49
50    Expr *rebuild(Expr *e) {
51      // Fast path: nothing to look through.
52      if (typename T::specific_type *specific
53            = dyn_cast<typename T::specific_type>(e))
54        return getDerived().rebuildSpecific(specific);
55
56      // Otherwise, we should look through and rebuild anything that
57      // IgnoreParens would.
58
59      if (ParenExpr *parens = dyn_cast<ParenExpr>(e)) {
60        e = rebuild(parens->getSubExpr());
61        return new (S.Context) ParenExpr(parens->getLParen(),
62                                         parens->getRParen(),
63                                         e);
64      }
65
66      if (UnaryOperator *uop = dyn_cast<UnaryOperator>(e)) {
67        assert(uop->getOpcode() == UO_Extension);
68        e = rebuild(uop->getSubExpr());
69        return new (S.Context) UnaryOperator(e, uop->getOpcode(),
70                                             uop->getType(),
71                                             uop->getValueKind(),
72                                             uop->getObjectKind(),
73                                             uop->getOperatorLoc());
74      }
75
76      if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
77        assert(!gse->isResultDependent());
78        unsigned resultIndex = gse->getResultIndex();
79        unsigned numAssocs = gse->getNumAssocs();
80
81        SmallVector<Expr*, 8> assocs(numAssocs);
82        SmallVector<TypeSourceInfo*, 8> assocTypes(numAssocs);
83
84        for (unsigned i = 0; i != numAssocs; ++i) {
85          Expr *assoc = gse->getAssocExpr(i);
86          if (i == resultIndex) assoc = rebuild(assoc);
87          assocs[i] = assoc;
88          assocTypes[i] = gse->getAssocTypeSourceInfo(i);
89        }
90
91        return new (S.Context) GenericSelectionExpr(S.Context,
92                                                    gse->getGenericLoc(),
93                                                    gse->getControllingExpr(),
94                                                    assocTypes.data(),
95                                                    assocs.data(),
96                                                    numAssocs,
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    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    virtual bool assignmentsHaveResult() { return true; }
202
203    virtual Expr *rebuildAndCaptureObject(Expr *) = 0;
204    virtual ExprResult buildGet() = 0;
205    virtual ExprResult buildSet(Expr *, SourceLocation,
206                                bool captureSetValueAsResult) = 0;
207  };
208
209  /// A PseudoOpBuilder for Objective-C @properties.
210  class ObjCPropertyOpBuilder : public PseudoOpBuilder {
211    ObjCPropertyRefExpr *RefExpr;
212    ObjCPropertyRefExpr *SyntacticRefExpr;
213    OpaqueValueExpr *InstanceReceiver;
214    ObjCMethodDecl *Getter;
215
216    ObjCMethodDecl *Setter;
217    Selector SetterSelector;
218    Selector GetterSelector;
219
220  public:
221    ObjCPropertyOpBuilder(Sema &S, ObjCPropertyRefExpr *refExpr) :
222      PseudoOpBuilder(S, refExpr->getLocation()), RefExpr(refExpr),
223      SyntacticRefExpr(0), InstanceReceiver(0), Getter(0), Setter(0) {
224    }
225
226    ExprResult buildRValueOperation(Expr *op);
227    ExprResult buildAssignmentOperation(Scope *Sc,
228                                        SourceLocation opLoc,
229                                        BinaryOperatorKind opcode,
230                                        Expr *LHS, Expr *RHS);
231    ExprResult buildIncDecOperation(Scope *Sc, SourceLocation opLoc,
232                                    UnaryOperatorKind opcode,
233                                    Expr *op);
234
235    bool tryBuildGetOfReference(Expr *op, ExprResult &result);
236    bool findSetter(bool warn=true);
237    bool findGetter();
238
239    Expr *rebuildAndCaptureObject(Expr *syntacticBase);
240    ExprResult buildGet();
241    ExprResult buildSet(Expr *op, SourceLocation, bool);
242  };
243
244 /// A PseudoOpBuilder for Objective-C array/dictionary indexing.
245 class ObjCSubscriptOpBuilder : public PseudoOpBuilder {
246   ObjCSubscriptRefExpr *RefExpr;
247   OpaqueValueExpr *InstanceBase;
248   OpaqueValueExpr *InstanceKey;
249   ObjCMethodDecl *AtIndexGetter;
250   Selector AtIndexGetterSelector;
251
252   ObjCMethodDecl *AtIndexSetter;
253   Selector AtIndexSetterSelector;
254
255 public:
256    ObjCSubscriptOpBuilder(Sema &S, ObjCSubscriptRefExpr *refExpr) :
257      PseudoOpBuilder(S, refExpr->getSourceRange().getBegin()),
258      RefExpr(refExpr),
259    InstanceBase(0), InstanceKey(0),
260    AtIndexGetter(0), AtIndexSetter(0) { }
261
262   ExprResult buildRValueOperation(Expr *op);
263   ExprResult buildAssignmentOperation(Scope *Sc,
264                                       SourceLocation opLoc,
265                                       BinaryOperatorKind opcode,
266                                       Expr *LHS, Expr *RHS);
267   Expr *rebuildAndCaptureObject(Expr *syntacticBase);
268
269   bool findAtIndexGetter();
270   bool findAtIndexSetter();
271
272   ExprResult buildGet();
273   ExprResult buildSet(Expr *op, SourceLocation, bool);
274 };
275
276}
277
278/// Capture the given expression in an OpaqueValueExpr.
279OpaqueValueExpr *PseudoOpBuilder::capture(Expr *e) {
280  // Make a new OVE whose source is the given expression.
281  OpaqueValueExpr *captured =
282    new (S.Context) OpaqueValueExpr(GenericLoc, e->getType(),
283                                    e->getValueKind(), e->getObjectKind(),
284                                    e);
285
286  // Make sure we bind that in the semantics.
287  addSemanticExpr(captured);
288  return captured;
289}
290
291/// Capture the given expression as the result of this pseudo-object
292/// operation.  This routine is safe against expressions which may
293/// already be captured.
294///
295/// \param Returns the captured expression, which will be the
296///   same as the input if the input was already captured
297OpaqueValueExpr *PseudoOpBuilder::captureValueAsResult(Expr *e) {
298  assert(ResultIndex == PseudoObjectExpr::NoResult);
299
300  // If the expression hasn't already been captured, just capture it
301  // and set the new semantic
302  if (!isa<OpaqueValueExpr>(e)) {
303    OpaqueValueExpr *cap = capture(e);
304    setResultToLastSemantic();
305    return cap;
306  }
307
308  // Otherwise, it must already be one of our semantic expressions;
309  // set ResultIndex to its index.
310  unsigned index = 0;
311  for (;; ++index) {
312    assert(index < Semantics.size() &&
313           "captured expression not found in semantics!");
314    if (e == Semantics[index]) break;
315  }
316  ResultIndex = index;
317  return cast<OpaqueValueExpr>(e);
318}
319
320/// The routine which creates the final PseudoObjectExpr.
321ExprResult PseudoOpBuilder::complete(Expr *syntactic) {
322  return PseudoObjectExpr::Create(S.Context, syntactic,
323                                  Semantics, ResultIndex);
324}
325
326/// The main skeleton for building an r-value operation.
327ExprResult PseudoOpBuilder::buildRValueOperation(Expr *op) {
328  Expr *syntacticBase = rebuildAndCaptureObject(op);
329
330  ExprResult getExpr = buildGet();
331  if (getExpr.isInvalid()) return ExprError();
332  addResultSemanticExpr(getExpr.take());
333
334  return complete(syntacticBase);
335}
336
337/// The basic skeleton for building a simple or compound
338/// assignment operation.
339ExprResult
340PseudoOpBuilder::buildAssignmentOperation(Scope *Sc, SourceLocation opcLoc,
341                                          BinaryOperatorKind opcode,
342                                          Expr *LHS, Expr *RHS) {
343  assert(BinaryOperator::isAssignmentOp(opcode));
344
345  Expr *syntacticLHS = rebuildAndCaptureObject(LHS);
346  OpaqueValueExpr *capturedRHS = capture(RHS);
347
348  Expr *syntactic;
349
350  ExprResult result;
351  if (opcode == BO_Assign) {
352    result = capturedRHS;
353    syntactic = new (S.Context) BinaryOperator(syntacticLHS, capturedRHS,
354                                               opcode, capturedRHS->getType(),
355                                               capturedRHS->getValueKind(),
356                                               OK_Ordinary, opcLoc);
357  } else {
358    ExprResult opLHS = buildGet();
359    if (opLHS.isInvalid()) return ExprError();
360
361    // Build an ordinary, non-compound operation.
362    BinaryOperatorKind nonCompound =
363      BinaryOperator::getOpForCompoundAssignment(opcode);
364    result = S.BuildBinOp(Sc, opcLoc, nonCompound,
365                          opLHS.take(), capturedRHS);
366    if (result.isInvalid()) return ExprError();
367
368    syntactic =
369      new (S.Context) CompoundAssignOperator(syntacticLHS, capturedRHS, opcode,
370                                             result.get()->getType(),
371                                             result.get()->getValueKind(),
372                                             OK_Ordinary,
373                                             opLHS.get()->getType(),
374                                             result.get()->getType(),
375                                             opcLoc);
376  }
377
378  // The result of the assignment, if not void, is the value set into
379  // the l-value.
380  result = buildSet(result.take(), opcLoc, assignmentsHaveResult());
381  if (result.isInvalid()) return ExprError();
382  addSemanticExpr(result.take());
383
384  return complete(syntactic);
385}
386
387/// The basic skeleton for building an increment or decrement
388/// operation.
389ExprResult
390PseudoOpBuilder::buildIncDecOperation(Scope *Sc, SourceLocation opcLoc,
391                                      UnaryOperatorKind opcode,
392                                      Expr *op) {
393  assert(UnaryOperator::isIncrementDecrementOp(opcode));
394
395  Expr *syntacticOp = rebuildAndCaptureObject(op);
396
397  // Load the value.
398  ExprResult result = buildGet();
399  if (result.isInvalid()) return ExprError();
400
401  QualType resultType = result.get()->getType();
402
403  // That's the postfix result.
404  if (UnaryOperator::isPostfix(opcode) && assignmentsHaveResult()) {
405    result = capture(result.take());
406    setResultToLastSemantic();
407  }
408
409  // Add or subtract a literal 1.
410  llvm::APInt oneV(S.Context.getTypeSize(S.Context.IntTy), 1);
411  Expr *one = IntegerLiteral::Create(S.Context, oneV, S.Context.IntTy,
412                                     GenericLoc);
413
414  if (UnaryOperator::isIncrementOp(opcode)) {
415    result = S.BuildBinOp(Sc, opcLoc, BO_Add, result.take(), one);
416  } else {
417    result = S.BuildBinOp(Sc, opcLoc, BO_Sub, result.take(), one);
418  }
419  if (result.isInvalid()) return ExprError();
420
421  // Store that back into the result.  The value stored is the result
422  // of a prefix operation.
423  result = buildSet(result.take(), opcLoc,
424             UnaryOperator::isPrefix(opcode) && assignmentsHaveResult());
425  if (result.isInvalid()) return ExprError();
426  addSemanticExpr(result.take());
427
428  UnaryOperator *syntactic =
429    new (S.Context) UnaryOperator(syntacticOp, opcode, resultType,
430                                  VK_LValue, OK_Ordinary, opcLoc);
431  return complete(syntactic);
432}
433
434
435//===----------------------------------------------------------------------===//
436//  Objective-C @property and implicit property references
437//===----------------------------------------------------------------------===//
438
439/// Look up a method in the receiver type of an Objective-C property
440/// reference.
441static ObjCMethodDecl *LookupMethodInReceiverType(Sema &S, Selector sel,
442                                            const ObjCPropertyRefExpr *PRE) {
443  if (PRE->isObjectReceiver()) {
444    const ObjCObjectPointerType *PT =
445      PRE->getBase()->getType()->castAs<ObjCObjectPointerType>();
446
447    // Special case for 'self' in class method implementations.
448    if (PT->isObjCClassType() &&
449        S.isSelfExpr(const_cast<Expr*>(PRE->getBase()))) {
450      // This cast is safe because isSelfExpr is only true within
451      // methods.
452      ObjCMethodDecl *method =
453        cast<ObjCMethodDecl>(S.CurContext->getNonClosureAncestor());
454      return S.LookupMethodInObjectType(sel,
455                 S.Context.getObjCInterfaceType(method->getClassInterface()),
456                                        /*instance*/ false);
457    }
458
459    return S.LookupMethodInObjectType(sel, PT->getPointeeType(), true);
460  }
461
462  if (PRE->isSuperReceiver()) {
463    if (const ObjCObjectPointerType *PT =
464        PRE->getSuperReceiverType()->getAs<ObjCObjectPointerType>())
465      return S.LookupMethodInObjectType(sel, PT->getPointeeType(), true);
466
467    return S.LookupMethodInObjectType(sel, PRE->getSuperReceiverType(), false);
468  }
469
470  assert(PRE->isClassReceiver() && "Invalid expression");
471  QualType IT = S.Context.getObjCInterfaceType(PRE->getClassReceiver());
472  return S.LookupMethodInObjectType(sel, IT, false);
473}
474
475bool ObjCPropertyOpBuilder::findGetter() {
476  if (Getter) return true;
477
478  // For implicit properties, just trust the lookup we already did.
479  if (RefExpr->isImplicitProperty()) {
480    if ((Getter = RefExpr->getImplicitPropertyGetter())) {
481      GetterSelector = Getter->getSelector();
482      return true;
483    }
484    else {
485      // Must build the getter selector the hard way.
486      ObjCMethodDecl *setter = RefExpr->getImplicitPropertySetter();
487      assert(setter && "both setter and getter are null - cannot happen");
488      IdentifierInfo *setterName =
489        setter->getSelector().getIdentifierInfoForSlot(0);
490      const char *compStr = setterName->getNameStart();
491      compStr += 3;
492      IdentifierInfo *getterName = &S.Context.Idents.get(compStr);
493      GetterSelector =
494        S.PP.getSelectorTable().getNullarySelector(getterName);
495      return false;
496
497    }
498  }
499
500  ObjCPropertyDecl *prop = RefExpr->getExplicitProperty();
501  Getter = LookupMethodInReceiverType(S, prop->getGetterName(), RefExpr);
502  return (Getter != 0);
503}
504
505/// Try to find the most accurate setter declaration for the property
506/// reference.
507///
508/// \return true if a setter was found, in which case Setter
509bool ObjCPropertyOpBuilder::findSetter(bool warn) {
510  // For implicit properties, just trust the lookup we already did.
511  if (RefExpr->isImplicitProperty()) {
512    if (ObjCMethodDecl *setter = RefExpr->getImplicitPropertySetter()) {
513      Setter = setter;
514      SetterSelector = setter->getSelector();
515      return true;
516    } else {
517      IdentifierInfo *getterName =
518        RefExpr->getImplicitPropertyGetter()->getSelector()
519          .getIdentifierInfoForSlot(0);
520      SetterSelector =
521        SelectorTable::constructSetterName(S.PP.getIdentifierTable(),
522                                           S.PP.getSelectorTable(),
523                                           getterName);
524      return false;
525    }
526  }
527
528  // For explicit properties, this is more involved.
529  ObjCPropertyDecl *prop = RefExpr->getExplicitProperty();
530  SetterSelector = prop->getSetterName();
531
532  // Do a normal method lookup first.
533  if (ObjCMethodDecl *setter =
534        LookupMethodInReceiverType(S, SetterSelector, RefExpr)) {
535    if (setter->isSynthesized() && warn)
536      if (const ObjCInterfaceDecl *IFace =
537          dyn_cast<ObjCInterfaceDecl>(setter->getDeclContext())) {
538        const StringRef thisPropertyName(prop->getName());
539        char front = thisPropertyName.front();
540        front = islower(front) ? toupper(front) : tolower(front);
541        SmallString<100> PropertyName = thisPropertyName;
542        PropertyName[0] = front;
543        IdentifierInfo *AltMember = &S.PP.getIdentifierTable().get(PropertyName);
544        if (ObjCPropertyDecl *prop1 = IFace->FindPropertyDeclaration(AltMember))
545          if (prop != prop1 && (prop1->getSetterMethodDecl() == setter)) {
546            S.Diag(RefExpr->getExprLoc(), diag::error_property_setter_ambiguous_use)
547              << prop->getName() << prop1->getName() << setter->getSelector();
548            S.Diag(prop->getLocation(), diag::note_property_declare);
549            S.Diag(prop1->getLocation(), diag::note_property_declare);
550          }
551      }
552    Setter = setter;
553    return true;
554  }
555
556  // That can fail in the somewhat crazy situation that we're
557  // type-checking a message send within the @interface declaration
558  // that declared the @property.  But it's not clear that that's
559  // valuable to support.
560
561  return false;
562}
563
564/// Capture the base object of an Objective-C property expression.
565Expr *ObjCPropertyOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
566  assert(InstanceReceiver == 0);
567
568  // If we have a base, capture it in an OVE and rebuild the syntactic
569  // form to use the OVE as its base.
570  if (RefExpr->isObjectReceiver()) {
571    InstanceReceiver = capture(RefExpr->getBase());
572
573    syntacticBase =
574      ObjCPropertyRefRebuilder(S, InstanceReceiver).rebuild(syntacticBase);
575  }
576
577  if (ObjCPropertyRefExpr *
578        refE = dyn_cast<ObjCPropertyRefExpr>(syntacticBase->IgnoreParens()))
579    SyntacticRefExpr = refE;
580
581  return syntacticBase;
582}
583
584/// Load from an Objective-C property reference.
585ExprResult ObjCPropertyOpBuilder::buildGet() {
586  findGetter();
587  assert(Getter);
588
589  if (SyntacticRefExpr)
590    SyntacticRefExpr->setIsMessagingGetter();
591
592  QualType receiverType;
593  if (RefExpr->isClassReceiver()) {
594    receiverType = S.Context.getObjCInterfaceType(RefExpr->getClassReceiver());
595  } else if (RefExpr->isSuperReceiver()) {
596    receiverType = RefExpr->getSuperReceiverType();
597  } else {
598    assert(InstanceReceiver);
599    receiverType = InstanceReceiver->getType();
600  }
601
602  // Build a message-send.
603  ExprResult msg;
604  if (Getter->isInstanceMethod() || RefExpr->isObjectReceiver()) {
605    assert(InstanceReceiver || RefExpr->isSuperReceiver());
606    msg = S.BuildInstanceMessageImplicit(InstanceReceiver, receiverType,
607                                         GenericLoc, Getter->getSelector(),
608                                         Getter, MultiExprArg());
609  } else {
610    msg = S.BuildClassMessageImplicit(receiverType, RefExpr->isSuperReceiver(),
611                                      GenericLoc,
612                                      Getter->getSelector(), Getter,
613                                      MultiExprArg());
614  }
615  return msg;
616}
617
618/// Store to an Objective-C property reference.
619///
620/// \param bindSetValueAsResult - If true, capture the actual
621///   value being set as the value of the property operation.
622ExprResult ObjCPropertyOpBuilder::buildSet(Expr *op, SourceLocation opcLoc,
623                                           bool captureSetValueAsResult) {
624  bool hasSetter = findSetter(false);
625  assert(hasSetter); (void) hasSetter;
626
627  if (SyntacticRefExpr)
628    SyntacticRefExpr->setIsMessagingSetter();
629
630  QualType receiverType;
631  if (RefExpr->isClassReceiver()) {
632    receiverType = S.Context.getObjCInterfaceType(RefExpr->getClassReceiver());
633  } else if (RefExpr->isSuperReceiver()) {
634    receiverType = RefExpr->getSuperReceiverType();
635  } else {
636    assert(InstanceReceiver);
637    receiverType = InstanceReceiver->getType();
638  }
639
640  // Use assignment constraints when possible; they give us better
641  // diagnostics.  "When possible" basically means anything except a
642  // C++ class type.
643  if (!S.getLangOpts().CPlusPlus || !op->getType()->isRecordType()) {
644    QualType paramType = (*Setter->param_begin())->getType();
645    if (!S.getLangOpts().CPlusPlus || !paramType->isRecordType()) {
646      ExprResult opResult = op;
647      Sema::AssignConvertType assignResult
648        = S.CheckSingleAssignmentConstraints(paramType, opResult);
649      if (S.DiagnoseAssignmentResult(assignResult, opcLoc, paramType,
650                                     op->getType(), opResult.get(),
651                                     Sema::AA_Assigning))
652        return ExprError();
653
654      op = opResult.take();
655      assert(op && "successful assignment left argument invalid?");
656    }
657  }
658
659  // Arguments.
660  Expr *args[] = { op };
661
662  // Build a message-send.
663  ExprResult msg;
664  if (Setter->isInstanceMethod() || RefExpr->isObjectReceiver()) {
665    msg = S.BuildInstanceMessageImplicit(InstanceReceiver, receiverType,
666                                         GenericLoc, SetterSelector, Setter,
667                                         MultiExprArg(args, 1));
668  } else {
669    msg = S.BuildClassMessageImplicit(receiverType, RefExpr->isSuperReceiver(),
670                                      GenericLoc,
671                                      SetterSelector, Setter,
672                                      MultiExprArg(args, 1));
673  }
674
675  if (!msg.isInvalid() && captureSetValueAsResult) {
676    ObjCMessageExpr *msgExpr =
677      cast<ObjCMessageExpr>(msg.get()->IgnoreImplicit());
678    Expr *arg = msgExpr->getArg(0);
679    msgExpr->setArg(0, captureValueAsResult(arg));
680  }
681
682  return msg;
683}
684
685/// @property-specific behavior for doing lvalue-to-rvalue conversion.
686ExprResult ObjCPropertyOpBuilder::buildRValueOperation(Expr *op) {
687  // Explicit properties always have getters, but implicit ones don't.
688  // Check that before proceeding.
689  if (RefExpr->isImplicitProperty() &&
690      !RefExpr->getImplicitPropertyGetter()) {
691    S.Diag(RefExpr->getLocation(), diag::err_getter_not_found)
692      << RefExpr->getBase()->getType();
693    return ExprError();
694  }
695
696  ExprResult result = PseudoOpBuilder::buildRValueOperation(op);
697  if (result.isInvalid()) return ExprError();
698
699  if (RefExpr->isExplicitProperty() && !Getter->hasRelatedResultType())
700    S.DiagnosePropertyAccessorMismatch(RefExpr->getExplicitProperty(),
701                                       Getter, RefExpr->getLocation());
702
703  // As a special case, if the method returns 'id', try to get
704  // a better type from the property.
705  if (RefExpr->isExplicitProperty() && result.get()->isRValue() &&
706      result.get()->getType()->isObjCIdType()) {
707    QualType propType = RefExpr->getExplicitProperty()->getType();
708    if (const ObjCObjectPointerType *ptr
709          = propType->getAs<ObjCObjectPointerType>()) {
710      if (!ptr->isObjCIdType())
711        result = S.ImpCastExprToType(result.get(), propType, CK_BitCast);
712    }
713  }
714
715  return result;
716}
717
718/// Try to build this as a call to a getter that returns a reference.
719///
720/// \return true if it was possible, whether or not it actually
721///   succeeded
722bool ObjCPropertyOpBuilder::tryBuildGetOfReference(Expr *op,
723                                                   ExprResult &result) {
724  if (!S.getLangOpts().CPlusPlus) return false;
725
726  findGetter();
727  assert(Getter && "property has no setter and no getter!");
728
729  // Only do this if the getter returns an l-value reference type.
730  QualType resultType = Getter->getResultType();
731  if (!resultType->isLValueReferenceType()) return false;
732
733  result = buildRValueOperation(op);
734  return true;
735}
736
737/// @property-specific behavior for doing assignments.
738ExprResult
739ObjCPropertyOpBuilder::buildAssignmentOperation(Scope *Sc,
740                                                SourceLocation opcLoc,
741                                                BinaryOperatorKind opcode,
742                                                Expr *LHS, Expr *RHS) {
743  assert(BinaryOperator::isAssignmentOp(opcode));
744
745  // If there's no setter, we have no choice but to try to assign to
746  // the result of the getter.
747  if (!findSetter()) {
748    ExprResult result;
749    if (tryBuildGetOfReference(LHS, result)) {
750      if (result.isInvalid()) return ExprError();
751      return S.BuildBinOp(Sc, opcLoc, opcode, result.take(), RHS);
752    }
753
754    // Otherwise, it's an error.
755    S.Diag(opcLoc, diag::err_nosetter_property_assignment)
756      << unsigned(RefExpr->isImplicitProperty())
757      << SetterSelector
758      << LHS->getSourceRange() << RHS->getSourceRange();
759    return ExprError();
760  }
761
762  // If there is a setter, we definitely want to use it.
763
764  // Verify that we can do a compound assignment.
765  if (opcode != BO_Assign && !findGetter()) {
766    S.Diag(opcLoc, diag::err_nogetter_property_compound_assignment)
767      << LHS->getSourceRange() << RHS->getSourceRange();
768    return ExprError();
769  }
770
771  ExprResult result =
772    PseudoOpBuilder::buildAssignmentOperation(Sc, opcLoc, opcode, LHS, RHS);
773  if (result.isInvalid()) return ExprError();
774
775  // Various warnings about property assignments in ARC.
776  if (S.getLangOpts().ObjCAutoRefCount && InstanceReceiver) {
777    S.checkRetainCycles(InstanceReceiver->getSourceExpr(), RHS);
778    S.checkUnsafeExprAssigns(opcLoc, LHS, RHS);
779  }
780
781  return result;
782}
783
784/// @property-specific behavior for doing increments and decrements.
785ExprResult
786ObjCPropertyOpBuilder::buildIncDecOperation(Scope *Sc, SourceLocation opcLoc,
787                                            UnaryOperatorKind opcode,
788                                            Expr *op) {
789  // If there's no setter, we have no choice but to try to assign to
790  // the result of the getter.
791  if (!findSetter()) {
792    ExprResult result;
793    if (tryBuildGetOfReference(op, result)) {
794      if (result.isInvalid()) return ExprError();
795      return S.BuildUnaryOp(Sc, opcLoc, opcode, result.take());
796    }
797
798    // Otherwise, it's an error.
799    S.Diag(opcLoc, diag::err_nosetter_property_incdec)
800      << unsigned(RefExpr->isImplicitProperty())
801      << unsigned(UnaryOperator::isDecrementOp(opcode))
802      << SetterSelector
803      << op->getSourceRange();
804    return ExprError();
805  }
806
807  // If there is a setter, we definitely want to use it.
808
809  // We also need a getter.
810  if (!findGetter()) {
811    assert(RefExpr->isImplicitProperty());
812    S.Diag(opcLoc, diag::err_nogetter_property_incdec)
813      << unsigned(UnaryOperator::isDecrementOp(opcode))
814      << GetterSelector
815      << op->getSourceRange();
816    return ExprError();
817  }
818
819  return PseudoOpBuilder::buildIncDecOperation(Sc, opcLoc, opcode, op);
820}
821
822// ObjCSubscript build stuff.
823//
824
825/// objective-c subscripting-specific behavior for doing lvalue-to-rvalue
826/// conversion.
827/// FIXME. Remove this routine if it is proven that no additional
828/// specifity is needed.
829ExprResult ObjCSubscriptOpBuilder::buildRValueOperation(Expr *op) {
830  ExprResult result = PseudoOpBuilder::buildRValueOperation(op);
831  if (result.isInvalid()) return ExprError();
832  return result;
833}
834
835/// objective-c subscripting-specific  behavior for doing assignments.
836ExprResult
837ObjCSubscriptOpBuilder::buildAssignmentOperation(Scope *Sc,
838                                                SourceLocation opcLoc,
839                                                BinaryOperatorKind opcode,
840                                                Expr *LHS, Expr *RHS) {
841  assert(BinaryOperator::isAssignmentOp(opcode));
842  // There must be a method to do the Index'ed assignment.
843  if (!findAtIndexSetter())
844    return ExprError();
845
846  // Verify that we can do a compound assignment.
847  if (opcode != BO_Assign && !findAtIndexGetter())
848    return ExprError();
849
850  ExprResult result =
851  PseudoOpBuilder::buildAssignmentOperation(Sc, opcLoc, opcode, LHS, RHS);
852  if (result.isInvalid()) return ExprError();
853
854  // Various warnings about objc Index'ed assignments in ARC.
855  if (S.getLangOpts().ObjCAutoRefCount && InstanceBase) {
856    S.checkRetainCycles(InstanceBase->getSourceExpr(), RHS);
857    S.checkUnsafeExprAssigns(opcLoc, LHS, RHS);
858  }
859
860  return result;
861}
862
863/// Capture the base object of an Objective-C Index'ed expression.
864Expr *ObjCSubscriptOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
865  assert(InstanceBase == 0);
866
867  // Capture base expression in an OVE and rebuild the syntactic
868  // form to use the OVE as its base expression.
869  InstanceBase = capture(RefExpr->getBaseExpr());
870  InstanceKey = capture(RefExpr->getKeyExpr());
871
872  syntacticBase =
873    ObjCSubscriptRefRebuilder(S, InstanceBase,
874                              InstanceKey).rebuild(syntacticBase);
875
876  return syntacticBase;
877}
878
879/// CheckSubscriptingKind - This routine decide what type
880/// of indexing represented by "FromE" is being done.
881Sema::ObjCSubscriptKind
882  Sema::CheckSubscriptingKind(Expr *FromE) {
883  // If the expression already has integral or enumeration type, we're golden.
884  QualType T = FromE->getType();
885  if (T->isIntegralOrEnumerationType())
886    return OS_Array;
887
888  // If we don't have a class type in C++, there's no way we can get an
889  // expression of integral or enumeration type.
890  const RecordType *RecordTy = T->getAs<RecordType>();
891  if (!RecordTy && T->isObjCObjectPointerType())
892    // All other scalar cases are assumed to be dictionary indexing which
893    // caller handles, with diagnostics if needed.
894    return OS_Dictionary;
895  if (!getLangOpts().CPlusPlus ||
896      !RecordTy || RecordTy->isIncompleteType()) {
897    // No indexing can be done. Issue diagnostics and quit.
898    const Expr *IndexExpr = FromE->IgnoreParenImpCasts();
899    if (isa<StringLiteral>(IndexExpr))
900      Diag(FromE->getExprLoc(), diag::err_objc_subscript_pointer)
901        << T << FixItHint::CreateInsertion(FromE->getExprLoc(), "@");
902    else
903      Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
904        << T;
905    return OS_Error;
906  }
907
908  // We must have a complete class type.
909  if (RequireCompleteType(FromE->getExprLoc(), T,
910                          diag::err_objc_index_incomplete_class_type, FromE))
911    return OS_Error;
912
913  // Look for a conversion to an integral, enumeration type, or
914  // objective-C pointer type.
915  UnresolvedSet<4> ViableConversions;
916  UnresolvedSet<4> ExplicitConversions;
917  const UnresolvedSetImpl *Conversions
918    = cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();
919
920  int NoIntegrals=0, NoObjCIdPointers=0;
921  SmallVector<CXXConversionDecl *, 4> ConversionDecls;
922
923  for (UnresolvedSetImpl::iterator I = Conversions->begin(),
924       E = Conversions->end();
925       I != E;
926       ++I) {
927    if (CXXConversionDecl *Conversion
928        = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) {
929      QualType CT = Conversion->getConversionType().getNonReferenceType();
930      if (CT->isIntegralOrEnumerationType()) {
931        ++NoIntegrals;
932        ConversionDecls.push_back(Conversion);
933      }
934      else if (CT->isObjCIdType() ||CT->isBlockPointerType()) {
935        ++NoObjCIdPointers;
936        ConversionDecls.push_back(Conversion);
937      }
938    }
939  }
940  if (NoIntegrals ==1 && NoObjCIdPointers == 0)
941    return OS_Array;
942  if (NoIntegrals == 0 && NoObjCIdPointers == 1)
943    return OS_Dictionary;
944  if (NoIntegrals == 0 && NoObjCIdPointers == 0) {
945    // No conversion function was found. Issue diagnostic and return.
946    Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
947      << FromE->getType();
948    return OS_Error;
949  }
950  Diag(FromE->getExprLoc(), diag::err_objc_multiple_subscript_type_conversion)
951      << FromE->getType();
952  for (unsigned int i = 0; i < ConversionDecls.size(); i++)
953    Diag(ConversionDecls[i]->getLocation(), diag::not_conv_function_declared_at);
954
955  return OS_Error;
956}
957
958bool ObjCSubscriptOpBuilder::findAtIndexGetter() {
959  if (AtIndexGetter)
960    return true;
961
962  Expr *BaseExpr = RefExpr->getBaseExpr();
963  QualType BaseT = BaseExpr->getType();
964
965  QualType ResultType;
966  if (const ObjCObjectPointerType *PTy =
967      BaseT->getAs<ObjCObjectPointerType>()) {
968    ResultType = PTy->getPointeeType();
969    if (const ObjCObjectType *iQFaceTy =
970        ResultType->getAsObjCQualifiedInterfaceType())
971      ResultType = iQFaceTy->getBaseType();
972  }
973  Sema::ObjCSubscriptKind Res =
974    S.CheckSubscriptingKind(RefExpr->getKeyExpr());
975  if (Res == Sema::OS_Error)
976    return false;
977  bool arrayRef = (Res == Sema::OS_Array);
978
979  if (ResultType.isNull()) {
980    S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
981      << BaseExpr->getType() << arrayRef;
982    return false;
983  }
984  if (!arrayRef) {
985    // dictionary subscripting.
986    // - (id)objectForKeyedSubscript:(id)key;
987    IdentifierInfo *KeyIdents[] = {
988      &S.Context.Idents.get("objectForKeyedSubscript")
989    };
990    AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
991  }
992  else {
993    // - (id)objectAtIndexedSubscript:(size_t)index;
994    IdentifierInfo *KeyIdents[] = {
995      &S.Context.Idents.get("objectAtIndexedSubscript")
996    };
997
998    AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
999  }
1000
1001  AtIndexGetter = S.LookupMethodInObjectType(AtIndexGetterSelector, ResultType,
1002                                             true /*instance*/);
1003  bool receiverIdType = (BaseT->isObjCIdType() ||
1004                         BaseT->isObjCQualifiedIdType());
1005
1006  if (!AtIndexGetter && S.getLangOpts().DebuggerObjCLiteral) {
1007    AtIndexGetter = ObjCMethodDecl::Create(S.Context, SourceLocation(),
1008                           SourceLocation(), AtIndexGetterSelector,
1009                           S.Context.getObjCIdType() /*ReturnType*/,
1010                           0 /*TypeSourceInfo */,
1011                           S.Context.getTranslationUnitDecl(),
1012                           true /*Instance*/, false/*isVariadic*/,
1013                           /*isSynthesized=*/false,
1014                           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
1015                           ObjCMethodDecl::Required,
1016                           false);
1017    ParmVarDecl *Argument = ParmVarDecl::Create(S.Context, AtIndexGetter,
1018                                                SourceLocation(), SourceLocation(),
1019                                                arrayRef ? &S.Context.Idents.get("index")
1020                                                         : &S.Context.Idents.get("key"),
1021                                                arrayRef ? S.Context.UnsignedLongTy
1022                                                         : S.Context.getObjCIdType(),
1023                                                /*TInfo=*/0,
1024                                                SC_None,
1025                                                SC_None,
1026                                                0);
1027    AtIndexGetter->setMethodParams(S.Context, Argument,
1028                                   ArrayRef<SourceLocation>());
1029  }
1030
1031  if (!AtIndexGetter) {
1032    if (!receiverIdType) {
1033      S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_method_not_found)
1034      << BaseExpr->getType() << 0 << arrayRef;
1035      return false;
1036    }
1037    AtIndexGetter =
1038      S.LookupInstanceMethodInGlobalPool(AtIndexGetterSelector,
1039                                         RefExpr->getSourceRange(),
1040                                         true, false);
1041  }
1042
1043  if (AtIndexGetter) {
1044    QualType T = AtIndexGetter->param_begin()[0]->getType();
1045    if ((arrayRef && !T->isIntegralOrEnumerationType()) ||
1046        (!arrayRef && !T->isObjCObjectPointerType())) {
1047      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1048             arrayRef ? diag::err_objc_subscript_index_type
1049                      : diag::err_objc_subscript_key_type) << T;
1050      S.Diag(AtIndexGetter->param_begin()[0]->getLocation(),
1051             diag::note_parameter_type) << T;
1052      return false;
1053    }
1054    QualType R = AtIndexGetter->getResultType();
1055    if (!R->isObjCObjectPointerType()) {
1056      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1057             diag::err_objc_indexing_method_result_type) << R << arrayRef;
1058      S.Diag(AtIndexGetter->getLocation(), diag::note_method_declared_at) <<
1059        AtIndexGetter->getDeclName();
1060    }
1061  }
1062  return true;
1063}
1064
1065bool ObjCSubscriptOpBuilder::findAtIndexSetter() {
1066  if (AtIndexSetter)
1067    return true;
1068
1069  Expr *BaseExpr = RefExpr->getBaseExpr();
1070  QualType BaseT = BaseExpr->getType();
1071
1072  QualType ResultType;
1073  if (const ObjCObjectPointerType *PTy =
1074      BaseT->getAs<ObjCObjectPointerType>()) {
1075    ResultType = PTy->getPointeeType();
1076    if (const ObjCObjectType *iQFaceTy =
1077        ResultType->getAsObjCQualifiedInterfaceType())
1078      ResultType = iQFaceTy->getBaseType();
1079  }
1080
1081  Sema::ObjCSubscriptKind Res =
1082    S.CheckSubscriptingKind(RefExpr->getKeyExpr());
1083  if (Res == Sema::OS_Error)
1084    return false;
1085  bool arrayRef = (Res == Sema::OS_Array);
1086
1087  if (ResultType.isNull()) {
1088    S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
1089      << BaseExpr->getType() << arrayRef;
1090    return false;
1091  }
1092
1093  if (!arrayRef) {
1094    // dictionary subscripting.
1095    // - (void)setObject:(id)object forKeyedSubscript:(id)key;
1096    IdentifierInfo *KeyIdents[] = {
1097      &S.Context.Idents.get("setObject"),
1098      &S.Context.Idents.get("forKeyedSubscript")
1099    };
1100    AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
1101  }
1102  else {
1103    // - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
1104    IdentifierInfo *KeyIdents[] = {
1105      &S.Context.Idents.get("setObject"),
1106      &S.Context.Idents.get("atIndexedSubscript")
1107    };
1108    AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
1109  }
1110  AtIndexSetter = S.LookupMethodInObjectType(AtIndexSetterSelector, ResultType,
1111                                             true /*instance*/);
1112
1113  bool receiverIdType = (BaseT->isObjCIdType() ||
1114                         BaseT->isObjCQualifiedIdType());
1115
1116  if (!AtIndexSetter && S.getLangOpts().DebuggerObjCLiteral) {
1117    TypeSourceInfo *ResultTInfo = 0;
1118    QualType ReturnType = S.Context.VoidTy;
1119    AtIndexSetter = ObjCMethodDecl::Create(S.Context, SourceLocation(),
1120                           SourceLocation(), AtIndexSetterSelector,
1121                           ReturnType,
1122                           ResultTInfo,
1123                           S.Context.getTranslationUnitDecl(),
1124                           true /*Instance*/, false/*isVariadic*/,
1125                           /*isSynthesized=*/false,
1126                           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
1127                           ObjCMethodDecl::Required,
1128                           false);
1129    SmallVector<ParmVarDecl *, 2> Params;
1130    ParmVarDecl *object = ParmVarDecl::Create(S.Context, AtIndexSetter,
1131                                                SourceLocation(), SourceLocation(),
1132                                                &S.Context.Idents.get("object"),
1133                                                S.Context.getObjCIdType(),
1134                                                /*TInfo=*/0,
1135                                                SC_None,
1136                                                SC_None,
1137                                                0);
1138    Params.push_back(object);
1139    ParmVarDecl *key = ParmVarDecl::Create(S.Context, AtIndexSetter,
1140                                                SourceLocation(), SourceLocation(),
1141                                                arrayRef ?  &S.Context.Idents.get("index")
1142                                                         :  &S.Context.Idents.get("key"),
1143                                                arrayRef ? S.Context.UnsignedLongTy
1144                                                         : S.Context.getObjCIdType(),
1145                                                /*TInfo=*/0,
1146                                                SC_None,
1147                                                SC_None,
1148                                                0);
1149    Params.push_back(key);
1150    AtIndexSetter->setMethodParams(S.Context, Params, ArrayRef<SourceLocation>());
1151  }
1152
1153  if (!AtIndexSetter) {
1154    if (!receiverIdType) {
1155      S.Diag(BaseExpr->getExprLoc(),
1156             diag::err_objc_subscript_method_not_found)
1157      << BaseExpr->getType() << 1 << arrayRef;
1158      return false;
1159    }
1160    AtIndexSetter =
1161      S.LookupInstanceMethodInGlobalPool(AtIndexSetterSelector,
1162                                         RefExpr->getSourceRange(),
1163                                         true, false);
1164  }
1165
1166  bool err = false;
1167  if (AtIndexSetter && arrayRef) {
1168    QualType T = AtIndexSetter->param_begin()[1]->getType();
1169    if (!T->isIntegralOrEnumerationType()) {
1170      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1171             diag::err_objc_subscript_index_type) << T;
1172      S.Diag(AtIndexSetter->param_begin()[1]->getLocation(),
1173             diag::note_parameter_type) << T;
1174      err = true;
1175    }
1176    T = AtIndexSetter->param_begin()[0]->getType();
1177    if (!T->isObjCObjectPointerType()) {
1178      S.Diag(RefExpr->getBaseExpr()->getExprLoc(),
1179             diag::err_objc_subscript_object_type) << T << arrayRef;
1180      S.Diag(AtIndexSetter->param_begin()[0]->getLocation(),
1181             diag::note_parameter_type) << T;
1182      err = true;
1183    }
1184  }
1185  else if (AtIndexSetter && !arrayRef)
1186    for (unsigned i=0; i <2; i++) {
1187      QualType T = AtIndexSetter->param_begin()[i]->getType();
1188      if (!T->isObjCObjectPointerType()) {
1189        if (i == 1)
1190          S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1191                 diag::err_objc_subscript_key_type) << T;
1192        else
1193          S.Diag(RefExpr->getBaseExpr()->getExprLoc(),
1194                 diag::err_objc_subscript_dic_object_type) << T;
1195        S.Diag(AtIndexSetter->param_begin()[i]->getLocation(),
1196               diag::note_parameter_type) << T;
1197        err = true;
1198      }
1199    }
1200
1201  return !err;
1202}
1203
1204// Get the object at "Index" position in the container.
1205// [BaseExpr objectAtIndexedSubscript : IndexExpr];
1206ExprResult ObjCSubscriptOpBuilder::buildGet() {
1207  if (!findAtIndexGetter())
1208    return ExprError();
1209
1210  QualType receiverType = InstanceBase->getType();
1211
1212  // Build a message-send.
1213  ExprResult msg;
1214  Expr *Index = InstanceKey;
1215
1216  // Arguments.
1217  Expr *args[] = { Index };
1218  assert(InstanceBase);
1219  msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
1220                                       GenericLoc,
1221                                       AtIndexGetterSelector, AtIndexGetter,
1222                                       MultiExprArg(args, 1));
1223  return msg;
1224}
1225
1226/// Store into the container the "op" object at "Index"'ed location
1227/// by building this messaging expression:
1228/// - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
1229/// \param bindSetValueAsResult - If true, capture the actual
1230///   value being set as the value of the property operation.
1231ExprResult ObjCSubscriptOpBuilder::buildSet(Expr *op, SourceLocation opcLoc,
1232                                           bool captureSetValueAsResult) {
1233  if (!findAtIndexSetter())
1234    return ExprError();
1235
1236  QualType receiverType = InstanceBase->getType();
1237  Expr *Index = InstanceKey;
1238
1239  // Arguments.
1240  Expr *args[] = { op, Index };
1241
1242  // Build a message-send.
1243  ExprResult msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
1244                                                  GenericLoc,
1245                                                  AtIndexSetterSelector,
1246                                                  AtIndexSetter,
1247                                                  MultiExprArg(args, 2));
1248
1249  if (!msg.isInvalid() && captureSetValueAsResult) {
1250    ObjCMessageExpr *msgExpr =
1251      cast<ObjCMessageExpr>(msg.get()->IgnoreImplicit());
1252    Expr *arg = msgExpr->getArg(0);
1253    msgExpr->setArg(0, captureValueAsResult(arg));
1254  }
1255
1256  return msg;
1257}
1258
1259//===----------------------------------------------------------------------===//
1260//  General Sema routines.
1261//===----------------------------------------------------------------------===//
1262
1263ExprResult Sema::checkPseudoObjectRValue(Expr *E) {
1264  Expr *opaqueRef = E->IgnoreParens();
1265  if (ObjCPropertyRefExpr *refExpr
1266        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1267    ObjCPropertyOpBuilder builder(*this, refExpr);
1268    return builder.buildRValueOperation(E);
1269  }
1270  else if (ObjCSubscriptRefExpr *refExpr
1271           = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1272    ObjCSubscriptOpBuilder builder(*this, refExpr);
1273    return builder.buildRValueOperation(E);
1274  } else {
1275    llvm_unreachable("unknown pseudo-object kind!");
1276  }
1277}
1278
1279/// Check an increment or decrement of a pseudo-object expression.
1280ExprResult Sema::checkPseudoObjectIncDec(Scope *Sc, SourceLocation opcLoc,
1281                                         UnaryOperatorKind opcode, Expr *op) {
1282  // Do nothing if the operand is dependent.
1283  if (op->isTypeDependent())
1284    return new (Context) UnaryOperator(op, opcode, Context.DependentTy,
1285                                       VK_RValue, OK_Ordinary, opcLoc);
1286
1287  assert(UnaryOperator::isIncrementDecrementOp(opcode));
1288  Expr *opaqueRef = op->IgnoreParens();
1289  if (ObjCPropertyRefExpr *refExpr
1290        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1291    ObjCPropertyOpBuilder builder(*this, refExpr);
1292    return builder.buildIncDecOperation(Sc, opcLoc, opcode, op);
1293  } else if (isa<ObjCSubscriptRefExpr>(opaqueRef)) {
1294    Diag(opcLoc, diag::err_illegal_container_subscripting_op);
1295    return ExprError();
1296  } else {
1297    llvm_unreachable("unknown pseudo-object kind!");
1298  }
1299}
1300
1301ExprResult Sema::checkPseudoObjectAssignment(Scope *S, SourceLocation opcLoc,
1302                                             BinaryOperatorKind opcode,
1303                                             Expr *LHS, Expr *RHS) {
1304  // Do nothing if either argument is dependent.
1305  if (LHS->isTypeDependent() || RHS->isTypeDependent())
1306    return new (Context) BinaryOperator(LHS, RHS, opcode, Context.DependentTy,
1307                                        VK_RValue, OK_Ordinary, opcLoc);
1308
1309  // Filter out non-overload placeholder types in the RHS.
1310  if (RHS->getType()->isNonOverloadPlaceholderType()) {
1311    ExprResult result = CheckPlaceholderExpr(RHS);
1312    if (result.isInvalid()) return ExprError();
1313    RHS = result.take();
1314  }
1315
1316  Expr *opaqueRef = LHS->IgnoreParens();
1317  if (ObjCPropertyRefExpr *refExpr
1318        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1319    ObjCPropertyOpBuilder builder(*this, refExpr);
1320    return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
1321  } else if (ObjCSubscriptRefExpr *refExpr
1322             = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1323    ObjCSubscriptOpBuilder builder(*this, refExpr);
1324    return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
1325  } else {
1326    llvm_unreachable("unknown pseudo-object kind!");
1327  }
1328}
1329
1330/// Given a pseudo-object reference, rebuild it without the opaque
1331/// values.  Basically, undo the behavior of rebuildAndCaptureObject.
1332/// This should never operate in-place.
1333static Expr *stripOpaqueValuesFromPseudoObjectRef(Sema &S, Expr *E) {
1334  Expr *opaqueRef = E->IgnoreParens();
1335  if (ObjCPropertyRefExpr *refExpr
1336        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1337    // Class and super property references don't have opaque values in them.
1338    if (refExpr->isClassReceiver() || refExpr->isSuperReceiver())
1339      return E;
1340
1341    assert(refExpr->isObjectReceiver() && "Unknown receiver kind?");
1342    OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBase());
1343    return ObjCPropertyRefRebuilder(S, baseOVE->getSourceExpr()).rebuild(E);
1344  } else if (ObjCSubscriptRefExpr *refExpr
1345               = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1346    OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBaseExpr());
1347    OpaqueValueExpr *keyOVE = cast<OpaqueValueExpr>(refExpr->getKeyExpr());
1348    return ObjCSubscriptRefRebuilder(S, baseOVE->getSourceExpr(),
1349                                     keyOVE->getSourceExpr()).rebuild(E);
1350  } else {
1351    llvm_unreachable("unknown pseudo-object kind!");
1352  }
1353}
1354
1355/// Given a pseudo-object expression, recreate what it looks like
1356/// syntactically without the attendant OpaqueValueExprs.
1357///
1358/// This is a hack which should be removed when TreeTransform is
1359/// capable of rebuilding a tree without stripping implicit
1360/// operations.
1361Expr *Sema::recreateSyntacticForm(PseudoObjectExpr *E) {
1362  Expr *syntax = E->getSyntacticForm();
1363  if (UnaryOperator *uop = dyn_cast<UnaryOperator>(syntax)) {
1364    Expr *op = stripOpaqueValuesFromPseudoObjectRef(*this, uop->getSubExpr());
1365    return new (Context) UnaryOperator(op, uop->getOpcode(), uop->getType(),
1366                                       uop->getValueKind(), uop->getObjectKind(),
1367                                       uop->getOperatorLoc());
1368  } else if (CompoundAssignOperator *cop
1369               = dyn_cast<CompoundAssignOperator>(syntax)) {
1370    Expr *lhs = stripOpaqueValuesFromPseudoObjectRef(*this, cop->getLHS());
1371    Expr *rhs = cast<OpaqueValueExpr>(cop->getRHS())->getSourceExpr();
1372    return new (Context) CompoundAssignOperator(lhs, rhs, cop->getOpcode(),
1373                                                cop->getType(),
1374                                                cop->getValueKind(),
1375                                                cop->getObjectKind(),
1376                                                cop->getComputationLHSType(),
1377                                                cop->getComputationResultType(),
1378                                                cop->getOperatorLoc());
1379  } else if (BinaryOperator *bop = dyn_cast<BinaryOperator>(syntax)) {
1380    Expr *lhs = stripOpaqueValuesFromPseudoObjectRef(*this, bop->getLHS());
1381    Expr *rhs = cast<OpaqueValueExpr>(bop->getRHS())->getSourceExpr();
1382    return new (Context) BinaryOperator(lhs, rhs, bop->getOpcode(),
1383                                        bop->getType(), bop->getValueKind(),
1384                                        bop->getObjectKind(),
1385                                        bop->getOperatorLoc());
1386  } else {
1387    assert(syntax->hasPlaceholderType(BuiltinType::PseudoObject));
1388    return stripOpaqueValuesFromPseudoObjectRef(*this, syntax);
1389  }
1390}
1391