SemaPseudoObject.cpp revision 9879556f250c7b692228e834d7fca8f1cb118bf6 
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
38using namespace clang;
39using namespace sema;
40
41namespace {
42  // Basically just a very focused copy of TreeTransform.
43  template <class T> struct Rebuilder {
44    Sema &S;
45    Rebuilder(Sema &S) : S(S) {}
46
47    T &getDerived() { return static_cast<T&>(*this); }
48
49    Expr *rebuild(Expr *e) {
50      // Fast path: nothing to look through.
51      if (typename T::specific_type *specific
52            = dyn_cast<typename T::specific_type>(e))
53        return getDerived().rebuildSpecific(specific);
54
55      // Otherwise, we should look through and rebuild anything that
56      // IgnoreParens would.
57
58      if (ParenExpr *parens = dyn_cast<ParenExpr>(e)) {
59        e = rebuild(parens->getSubExpr());
60        return new (S.Context) ParenExpr(parens->getLParen(),
61                                         parens->getRParen(),
62                                         e);
63      }
64
65      if (UnaryOperator *uop = dyn_cast<UnaryOperator>(e)) {
66        assert(uop->getOpcode() == UO_Extension);
67        e = rebuild(uop->getSubExpr());
68        return new (S.Context) UnaryOperator(e, uop->getOpcode(),
69                                             uop->getType(),
70                                             uop->getValueKind(),
71                                             uop->getObjectKind(),
72                                             uop->getOperatorLoc());
73      }
74
75      if (GenericSelectionExpr *gse = dyn_cast<GenericSelectionExpr>(e)) {
76        assert(!gse->isResultDependent());
77        unsigned resultIndex = gse->getResultIndex();
78        unsigned numAssocs = gse->getNumAssocs();
79
80        SmallVector<Expr*, 8> assocs(numAssocs);
81        SmallVector<TypeSourceInfo*, 8> assocTypes(numAssocs);
82
83        for (unsigned i = 0; i != numAssocs; ++i) {
84          Expr *assoc = gse->getAssocExpr(i);
85          if (i == resultIndex) assoc = rebuild(assoc);
86          assocs[i] = assoc;
87          assocTypes[i] = gse->getAssocTypeSourceInfo(i);
88        }
89
90        return new (S.Context) GenericSelectionExpr(S.Context,
91                                                    gse->getGenericLoc(),
92                                                    gse->getControllingExpr(),
93                                                    assocTypes.data(),
94                                                    assocs.data(),
95                                                    numAssocs,
96                                                    gse->getDefaultLoc(),
97                                                    gse->getRParenLoc(),
98                                      gse->containsUnexpandedParameterPack(),
99                                                    resultIndex);
100      }
101
102      llvm_unreachable("bad expression to rebuild!");
103    }
104  };
105
106  struct ObjCPropertyRefRebuilder : Rebuilder<ObjCPropertyRefRebuilder> {
107    Expr *NewBase;
108    ObjCPropertyRefRebuilder(Sema &S, Expr *newBase)
109      : Rebuilder<ObjCPropertyRefRebuilder>(S), NewBase(newBase) {}
110
111    typedef ObjCPropertyRefExpr specific_type;
112    Expr *rebuildSpecific(ObjCPropertyRefExpr *refExpr) {
113      // Fortunately, the constraint that we're rebuilding something
114      // with a base limits the number of cases here.
115      assert(refExpr->getBase());
116
117      if (refExpr->isExplicitProperty()) {
118        return new (S.Context)
119          ObjCPropertyRefExpr(refExpr->getExplicitProperty(),
120                              refExpr->getType(), refExpr->getValueKind(),
121                              refExpr->getObjectKind(), refExpr->getLocation(),
122                              NewBase);
123      }
124      return new (S.Context)
125        ObjCPropertyRefExpr(refExpr->getImplicitPropertyGetter(),
126                            refExpr->getImplicitPropertySetter(),
127                            refExpr->getType(), refExpr->getValueKind(),
128                            refExpr->getObjectKind(),refExpr->getLocation(),
129                            NewBase);
130    }
131  };
132
133  struct ObjCSubscriptRefRebuilder : Rebuilder<ObjCSubscriptRefRebuilder> {
134    Expr *NewBase;
135    Expr *NewKeyExpr;
136    ObjCSubscriptRefRebuilder(Sema &S, Expr *newBase, Expr *newKeyExpr)
137    : Rebuilder<ObjCSubscriptRefRebuilder>(S),
138      NewBase(newBase), NewKeyExpr(newKeyExpr) {}
139
140    typedef ObjCSubscriptRefExpr specific_type;
141    Expr *rebuildSpecific(ObjCSubscriptRefExpr *refExpr) {
142      assert(refExpr->getBaseExpr());
143      assert(refExpr->getKeyExpr());
144
145      return new (S.Context)
146        ObjCSubscriptRefExpr(NewBase,
147                             NewKeyExpr,
148                             refExpr->getType(), refExpr->getValueKind(),
149                             refExpr->getObjectKind(),refExpr->getAtIndexMethodDecl(),
150                             refExpr->setAtIndexMethodDecl(),
151                             refExpr->getRBracket());
152    }
153  };
154
155  class PseudoOpBuilder {
156  public:
157    Sema &S;
158    unsigned ResultIndex;
159    SourceLocation GenericLoc;
160    SmallVector<Expr *, 4> Semantics;
161
162    PseudoOpBuilder(Sema &S, SourceLocation genericLoc)
163      : S(S), ResultIndex(PseudoObjectExpr::NoResult),
164        GenericLoc(genericLoc) {}
165
166    virtual ~PseudoOpBuilder() {}
167
168    /// Add a normal semantic expression.
169    void addSemanticExpr(Expr *semantic) {
170      Semantics.push_back(semantic);
171    }
172
173    /// Add the 'result' semantic expression.
174    void addResultSemanticExpr(Expr *resultExpr) {
175      assert(ResultIndex == PseudoObjectExpr::NoResult);
176      ResultIndex = Semantics.size();
177      Semantics.push_back(resultExpr);
178    }
179
180    ExprResult buildRValueOperation(Expr *op);
181    ExprResult buildAssignmentOperation(Scope *Sc,
182                                        SourceLocation opLoc,
183                                        BinaryOperatorKind opcode,
184                                        Expr *LHS, Expr *RHS);
185    ExprResult buildIncDecOperation(Scope *Sc, SourceLocation opLoc,
186                                    UnaryOperatorKind opcode,
187                                    Expr *op);
188
189    ExprResult complete(Expr *syntacticForm);
190
191    OpaqueValueExpr *capture(Expr *op);
192    OpaqueValueExpr *captureValueAsResult(Expr *op);
193
194    void setResultToLastSemantic() {
195      assert(ResultIndex == PseudoObjectExpr::NoResult);
196      ResultIndex = Semantics.size() - 1;
197    }
198
199    /// Return true if assignments have a non-void result.
200    virtual bool assignmentsHaveResult() { return true; }
201
202    virtual Expr *rebuildAndCaptureObject(Expr *) = 0;
203    virtual ExprResult buildGet() = 0;
204    virtual ExprResult buildSet(Expr *, SourceLocation,
205                                bool captureSetValueAsResult) = 0;
206  };
207
208  /// A PseudoOpBuilder for Objective-C @properties.
209  class ObjCPropertyOpBuilder : public PseudoOpBuilder {
210    ObjCPropertyRefExpr *RefExpr;
211    ObjCPropertyRefExpr *SyntacticRefExpr;
212    OpaqueValueExpr *InstanceReceiver;
213    ObjCMethodDecl *Getter;
214
215    ObjCMethodDecl *Setter;
216    Selector SetterSelector;
217    Selector GetterSelector;
218
219  public:
220    ObjCPropertyOpBuilder(Sema &S, ObjCPropertyRefExpr *refExpr) :
221      PseudoOpBuilder(S, refExpr->getLocation()), RefExpr(refExpr),
222      SyntacticRefExpr(0), InstanceReceiver(0), Getter(0), Setter(0) {
223    }
224
225    ExprResult buildRValueOperation(Expr *op);
226    ExprResult buildAssignmentOperation(Scope *Sc,
227                                        SourceLocation opLoc,
228                                        BinaryOperatorKind opcode,
229                                        Expr *LHS, Expr *RHS);
230    ExprResult buildIncDecOperation(Scope *Sc, SourceLocation opLoc,
231                                    UnaryOperatorKind opcode,
232                                    Expr *op);
233
234    bool tryBuildGetOfReference(Expr *op, ExprResult &result);
235    bool findSetter();
236    bool findGetter();
237
238    Expr *rebuildAndCaptureObject(Expr *syntacticBase);
239    ExprResult buildGet();
240    ExprResult buildSet(Expr *op, SourceLocation, bool);
241  };
242
243 /// A PseudoOpBuilder for Objective-C array/dictionary indexing.
244 class ObjCSubscriptOpBuilder : public PseudoOpBuilder {
245   ObjCSubscriptRefExpr *RefExpr;
246   OpaqueValueExpr *InstanceBase;
247   OpaqueValueExpr *InstanceKey;
248   ObjCMethodDecl *AtIndexGetter;
249   Selector AtIndexGetterSelector;
250
251   ObjCMethodDecl *AtIndexSetter;
252   Selector AtIndexSetterSelector;
253
254 public:
255    ObjCSubscriptOpBuilder(Sema &S, ObjCSubscriptRefExpr *refExpr) :
256      PseudoOpBuilder(S, refExpr->getSourceRange().getBegin()),
257      RefExpr(refExpr),
258    InstanceBase(0), InstanceKey(0),
259    AtIndexGetter(0), AtIndexSetter(0) { }
260
261   ExprResult buildRValueOperation(Expr *op);
262   ExprResult buildAssignmentOperation(Scope *Sc,
263                                       SourceLocation opLoc,
264                                       BinaryOperatorKind opcode,
265                                       Expr *LHS, Expr *RHS);
266   Expr *rebuildAndCaptureObject(Expr *syntacticBase);
267
268   bool findAtIndexGetter();
269   bool findAtIndexSetter();
270
271   ExprResult buildGet();
272   ExprResult buildSet(Expr *op, SourceLocation, bool);
273 };
274
275}
276
277/// Capture the given expression in an OpaqueValueExpr.
278OpaqueValueExpr *PseudoOpBuilder::capture(Expr *e) {
279  // Make a new OVE whose source is the given expression.
280  OpaqueValueExpr *captured =
281    new (S.Context) OpaqueValueExpr(GenericLoc, e->getType(),
282                                    e->getValueKind(), e->getObjectKind(),
283                                    e);
284
285  // Make sure we bind that in the semantics.
286  addSemanticExpr(captured);
287  return captured;
288}
289
290/// Capture the given expression as the result of this pseudo-object
291/// operation.  This routine is safe against expressions which may
292/// already be captured.
293///
294/// \param Returns the captured expression, which will be the
295///   same as the input if the input was already captured
296OpaqueValueExpr *PseudoOpBuilder::captureValueAsResult(Expr *e) {
297  assert(ResultIndex == PseudoObjectExpr::NoResult);
298
299  // If the expression hasn't already been captured, just capture it
300  // and set the new semantic
301  if (!isa<OpaqueValueExpr>(e)) {
302    OpaqueValueExpr *cap = capture(e);
303    setResultToLastSemantic();
304    return cap;
305  }
306
307  // Otherwise, it must already be one of our semantic expressions;
308  // set ResultIndex to its index.
309  unsigned index = 0;
310  for (;; ++index) {
311    assert(index < Semantics.size() &&
312           "captured expression not found in semantics!");
313    if (e == Semantics[index]) break;
314  }
315  ResultIndex = index;
316  return cast<OpaqueValueExpr>(e);
317}
318
319/// The routine which creates the final PseudoObjectExpr.
320ExprResult PseudoOpBuilder::complete(Expr *syntactic) {
321  return PseudoObjectExpr::Create(S.Context, syntactic,
322                                  Semantics, ResultIndex);
323}
324
325/// The main skeleton for building an r-value operation.
326ExprResult PseudoOpBuilder::buildRValueOperation(Expr *op) {
327  Expr *syntacticBase = rebuildAndCaptureObject(op);
328
329  ExprResult getExpr = buildGet();
330  if (getExpr.isInvalid()) return ExprError();
331  addResultSemanticExpr(getExpr.take());
332
333  return complete(syntacticBase);
334}
335
336/// The basic skeleton for building a simple or compound
337/// assignment operation.
338ExprResult
339PseudoOpBuilder::buildAssignmentOperation(Scope *Sc, SourceLocation opcLoc,
340                                          BinaryOperatorKind opcode,
341                                          Expr *LHS, Expr *RHS) {
342  assert(BinaryOperator::isAssignmentOp(opcode));
343
344  Expr *syntacticLHS = rebuildAndCaptureObject(LHS);
345  OpaqueValueExpr *capturedRHS = capture(RHS);
346
347  Expr *syntactic;
348
349  ExprResult result;
350  if (opcode == BO_Assign) {
351    result = capturedRHS;
352    syntactic = new (S.Context) BinaryOperator(syntacticLHS, capturedRHS,
353                                               opcode, capturedRHS->getType(),
354                                               capturedRHS->getValueKind(),
355                                               OK_Ordinary, opcLoc);
356  } else {
357    ExprResult opLHS = buildGet();
358    if (opLHS.isInvalid()) return ExprError();
359
360    // Build an ordinary, non-compound operation.
361    BinaryOperatorKind nonCompound =
362      BinaryOperator::getOpForCompoundAssignment(opcode);
363    result = S.BuildBinOp(Sc, opcLoc, nonCompound,
364                          opLHS.take(), capturedRHS);
365    if (result.isInvalid()) return ExprError();
366
367    syntactic =
368      new (S.Context) CompoundAssignOperator(syntacticLHS, capturedRHS, opcode,
369                                             result.get()->getType(),
370                                             result.get()->getValueKind(),
371                                             OK_Ordinary,
372                                             opLHS.get()->getType(),
373                                             result.get()->getType(),
374                                             opcLoc);
375  }
376
377  // The result of the assignment, if not void, is the value set into
378  // the l-value.
379  result = buildSet(result.take(), opcLoc, assignmentsHaveResult());
380  if (result.isInvalid()) return ExprError();
381  addSemanticExpr(result.take());
382
383  return complete(syntactic);
384}
385
386/// The basic skeleton for building an increment or decrement
387/// operation.
388ExprResult
389PseudoOpBuilder::buildIncDecOperation(Scope *Sc, SourceLocation opcLoc,
390                                      UnaryOperatorKind opcode,
391                                      Expr *op) {
392  assert(UnaryOperator::isIncrementDecrementOp(opcode));
393
394  Expr *syntacticOp = rebuildAndCaptureObject(op);
395
396  // Load the value.
397  ExprResult result = buildGet();
398  if (result.isInvalid()) return ExprError();
399
400  QualType resultType = result.get()->getType();
401
402  // That's the postfix result.
403  if (UnaryOperator::isPostfix(opcode) && assignmentsHaveResult()) {
404    result = capture(result.take());
405    setResultToLastSemantic();
406  }
407
408  // Add or subtract a literal 1.
409  llvm::APInt oneV(S.Context.getTypeSize(S.Context.IntTy), 1);
410  Expr *one = IntegerLiteral::Create(S.Context, oneV, S.Context.IntTy,
411                                     GenericLoc);
412
413  if (UnaryOperator::isIncrementOp(opcode)) {
414    result = S.BuildBinOp(Sc, opcLoc, BO_Add, result.take(), one);
415  } else {
416    result = S.BuildBinOp(Sc, opcLoc, BO_Sub, result.take(), one);
417  }
418  if (result.isInvalid()) return ExprError();
419
420  // Store that back into the result.  The value stored is the result
421  // of a prefix operation.
422  result = buildSet(result.take(), opcLoc,
423             UnaryOperator::isPrefix(opcode) && assignmentsHaveResult());
424  if (result.isInvalid()) return ExprError();
425  addSemanticExpr(result.take());
426
427  UnaryOperator *syntactic =
428    new (S.Context) UnaryOperator(syntacticOp, opcode, resultType,
429                                  VK_LValue, OK_Ordinary, opcLoc);
430  return complete(syntactic);
431}
432
433
434//===----------------------------------------------------------------------===//
435//  Objective-C @property and implicit property references
436//===----------------------------------------------------------------------===//
437
438/// Look up a method in the receiver type of an Objective-C property
439/// reference.
440static ObjCMethodDecl *LookupMethodInReceiverType(Sema &S, Selector sel,
441                                            const ObjCPropertyRefExpr *PRE) {
442  if (PRE->isObjectReceiver()) {
443    const ObjCObjectPointerType *PT =
444      PRE->getBase()->getType()->castAs<ObjCObjectPointerType>();
445
446    // Special case for 'self' in class method implementations.
447    if (PT->isObjCClassType() &&
448        S.isSelfExpr(const_cast<Expr*>(PRE->getBase()))) {
449      // This cast is safe because isSelfExpr is only true within
450      // methods.
451      ObjCMethodDecl *method =
452        cast<ObjCMethodDecl>(S.CurContext->getNonClosureAncestor());
453      return S.LookupMethodInObjectType(sel,
454                 S.Context.getObjCInterfaceType(method->getClassInterface()),
455                                        /*instance*/ false);
456    }
457
458    return S.LookupMethodInObjectType(sel, PT->getPointeeType(), true);
459  }
460
461  if (PRE->isSuperReceiver()) {
462    if (const ObjCObjectPointerType *PT =
463        PRE->getSuperReceiverType()->getAs<ObjCObjectPointerType>())
464      return S.LookupMethodInObjectType(sel, PT->getPointeeType(), true);
465
466    return S.LookupMethodInObjectType(sel, PRE->getSuperReceiverType(), false);
467  }
468
469  assert(PRE->isClassReceiver() && "Invalid expression");
470  QualType IT = S.Context.getObjCInterfaceType(PRE->getClassReceiver());
471  return S.LookupMethodInObjectType(sel, IT, false);
472}
473
474bool ObjCPropertyOpBuilder::findGetter() {
475  if (Getter) return true;
476
477  // For implicit properties, just trust the lookup we already did.
478  if (RefExpr->isImplicitProperty()) {
479    if ((Getter = RefExpr->getImplicitPropertyGetter())) {
480      GetterSelector = Getter->getSelector();
481      return true;
482    }
483    else {
484      // Must build the getter selector the hard way.
485      ObjCMethodDecl *setter = RefExpr->getImplicitPropertySetter();
486      assert(setter && "both setter and getter are null - cannot happen");
487      IdentifierInfo *setterName =
488        setter->getSelector().getIdentifierInfoForSlot(0);
489      const char *compStr = setterName->getNameStart();
490      compStr += 3;
491      IdentifierInfo *getterName = &S.Context.Idents.get(compStr);
492      GetterSelector =
493        S.PP.getSelectorTable().getNullarySelector(getterName);
494      return false;
495
496    }
497  }
498
499  ObjCPropertyDecl *prop = RefExpr->getExplicitProperty();
500  Getter = LookupMethodInReceiverType(S, prop->getGetterName(), RefExpr);
501  return (Getter != 0);
502}
503
504/// Try to find the most accurate setter declaration for the property
505/// reference.
506///
507/// \return true if a setter was found, in which case Setter
508bool ObjCPropertyOpBuilder::findSetter() {
509  // For implicit properties, just trust the lookup we already did.
510  if (RefExpr->isImplicitProperty()) {
511    if (ObjCMethodDecl *setter = RefExpr->getImplicitPropertySetter()) {
512      Setter = setter;
513      SetterSelector = setter->getSelector();
514      return true;
515    } else {
516      IdentifierInfo *getterName =
517        RefExpr->getImplicitPropertyGetter()->getSelector()
518          .getIdentifierInfoForSlot(0);
519      SetterSelector =
520        SelectorTable::constructSetterName(S.PP.getIdentifierTable(),
521                                           S.PP.getSelectorTable(),
522                                           getterName);
523      return false;
524    }
525  }
526
527  // For explicit properties, this is more involved.
528  ObjCPropertyDecl *prop = RefExpr->getExplicitProperty();
529  SetterSelector = prop->getSetterName();
530
531  // Do a normal method lookup first.
532  if (ObjCMethodDecl *setter =
533        LookupMethodInReceiverType(S, SetterSelector, RefExpr)) {
534    Setter = setter;
535    return true;
536  }
537
538  // That can fail in the somewhat crazy situation that we're
539  // type-checking a message send within the @interface declaration
540  // that declared the @property.  But it's not clear that that's
541  // valuable to support.
542
543  return false;
544}
545
546/// Capture the base object of an Objective-C property expression.
547Expr *ObjCPropertyOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
548  assert(InstanceReceiver == 0);
549
550  // If we have a base, capture it in an OVE and rebuild the syntactic
551  // form to use the OVE as its base.
552  if (RefExpr->isObjectReceiver()) {
553    InstanceReceiver = capture(RefExpr->getBase());
554
555    syntacticBase =
556      ObjCPropertyRefRebuilder(S, InstanceReceiver).rebuild(syntacticBase);
557  }
558
559  if (ObjCPropertyRefExpr *
560        refE = dyn_cast<ObjCPropertyRefExpr>(syntacticBase->IgnoreParens()))
561    SyntacticRefExpr = refE;
562
563  return syntacticBase;
564}
565
566/// Load from an Objective-C property reference.
567ExprResult ObjCPropertyOpBuilder::buildGet() {
568  findGetter();
569  assert(Getter);
570
571  if (SyntacticRefExpr)
572    SyntacticRefExpr->setIsMessagingGetter();
573
574  QualType receiverType;
575  if (RefExpr->isClassReceiver()) {
576    receiverType = S.Context.getObjCInterfaceType(RefExpr->getClassReceiver());
577  } else if (RefExpr->isSuperReceiver()) {
578    receiverType = RefExpr->getSuperReceiverType();
579  } else {
580    assert(InstanceReceiver);
581    receiverType = InstanceReceiver->getType();
582  }
583
584  // Build a message-send.
585  ExprResult msg;
586  if (Getter->isInstanceMethod() || RefExpr->isObjectReceiver()) {
587    assert(InstanceReceiver || RefExpr->isSuperReceiver());
588    msg = S.BuildInstanceMessageImplicit(InstanceReceiver, receiverType,
589                                         GenericLoc, Getter->getSelector(),
590                                         Getter, MultiExprArg());
591  } else {
592    msg = S.BuildClassMessageImplicit(receiverType, RefExpr->isSuperReceiver(),
593                                      GenericLoc,
594                                      Getter->getSelector(), Getter,
595                                      MultiExprArg());
596  }
597  return msg;
598}
599
600/// Store to an Objective-C property reference.
601///
602/// \param bindSetValueAsResult - If true, capture the actual
603///   value being set as the value of the property operation.
604ExprResult ObjCPropertyOpBuilder::buildSet(Expr *op, SourceLocation opcLoc,
605                                           bool captureSetValueAsResult) {
606  bool hasSetter = findSetter();
607  assert(hasSetter); (void) hasSetter;
608
609  if (SyntacticRefExpr)
610    SyntacticRefExpr->setIsMessagingSetter();
611
612  QualType receiverType;
613  if (RefExpr->isClassReceiver()) {
614    receiverType = S.Context.getObjCInterfaceType(RefExpr->getClassReceiver());
615  } else if (RefExpr->isSuperReceiver()) {
616    receiverType = RefExpr->getSuperReceiverType();
617  } else {
618    assert(InstanceReceiver);
619    receiverType = InstanceReceiver->getType();
620  }
621
622  // Use assignment constraints when possible; they give us better
623  // diagnostics.  "When possible" basically means anything except a
624  // C++ class type.
625  if (!S.getLangOpts().CPlusPlus || !op->getType()->isRecordType()) {
626    QualType paramType = (*Setter->param_begin())->getType();
627    if (!S.getLangOpts().CPlusPlus || !paramType->isRecordType()) {
628      ExprResult opResult = op;
629      Sema::AssignConvertType assignResult
630        = S.CheckSingleAssignmentConstraints(paramType, opResult);
631      if (S.DiagnoseAssignmentResult(assignResult, opcLoc, paramType,
632                                     op->getType(), opResult.get(),
633                                     Sema::AA_Assigning))
634        return ExprError();
635
636      op = opResult.take();
637      assert(op && "successful assignment left argument invalid?");
638    }
639  }
640
641  // Arguments.
642  Expr *args[] = { op };
643
644  // Build a message-send.
645  ExprResult msg;
646  if (Setter->isInstanceMethod() || RefExpr->isObjectReceiver()) {
647    msg = S.BuildInstanceMessageImplicit(InstanceReceiver, receiverType,
648                                         GenericLoc, SetterSelector, Setter,
649                                         MultiExprArg(args, 1));
650  } else {
651    msg = S.BuildClassMessageImplicit(receiverType, RefExpr->isSuperReceiver(),
652                                      GenericLoc,
653                                      SetterSelector, Setter,
654                                      MultiExprArg(args, 1));
655  }
656
657  if (!msg.isInvalid() && captureSetValueAsResult) {
658    ObjCMessageExpr *msgExpr =
659      cast<ObjCMessageExpr>(msg.get()->IgnoreImplicit());
660    Expr *arg = msgExpr->getArg(0);
661    msgExpr->setArg(0, captureValueAsResult(arg));
662  }
663
664  return msg;
665}
666
667/// @property-specific behavior for doing lvalue-to-rvalue conversion.
668ExprResult ObjCPropertyOpBuilder::buildRValueOperation(Expr *op) {
669  // Explicit properties always have getters, but implicit ones don't.
670  // Check that before proceeding.
671  if (RefExpr->isImplicitProperty() &&
672      !RefExpr->getImplicitPropertyGetter()) {
673    S.Diag(RefExpr->getLocation(), diag::err_getter_not_found)
674      << RefExpr->getBase()->getType();
675    return ExprError();
676  }
677
678  ExprResult result = PseudoOpBuilder::buildRValueOperation(op);
679  if (result.isInvalid()) return ExprError();
680
681  if (RefExpr->isExplicitProperty() && !Getter->hasRelatedResultType())
682    S.DiagnosePropertyAccessorMismatch(RefExpr->getExplicitProperty(),
683                                       Getter, RefExpr->getLocation());
684
685  // As a special case, if the method returns 'id', try to get
686  // a better type from the property.
687  if (RefExpr->isExplicitProperty() && result.get()->isRValue() &&
688      result.get()->getType()->isObjCIdType()) {
689    QualType propType = RefExpr->getExplicitProperty()->getType();
690    if (const ObjCObjectPointerType *ptr
691          = propType->getAs<ObjCObjectPointerType>()) {
692      if (!ptr->isObjCIdType())
693        result = S.ImpCastExprToType(result.get(), propType, CK_BitCast);
694    }
695  }
696
697  return result;
698}
699
700/// Try to build this as a call to a getter that returns a reference.
701///
702/// \return true if it was possible, whether or not it actually
703///   succeeded
704bool ObjCPropertyOpBuilder::tryBuildGetOfReference(Expr *op,
705                                                   ExprResult &result) {
706  if (!S.getLangOpts().CPlusPlus) return false;
707
708  findGetter();
709  assert(Getter && "property has no setter and no getter!");
710
711  // Only do this if the getter returns an l-value reference type.
712  QualType resultType = Getter->getResultType();
713  if (!resultType->isLValueReferenceType()) return false;
714
715  result = buildRValueOperation(op);
716  return true;
717}
718
719/// @property-specific behavior for doing assignments.
720ExprResult
721ObjCPropertyOpBuilder::buildAssignmentOperation(Scope *Sc,
722                                                SourceLocation opcLoc,
723                                                BinaryOperatorKind opcode,
724                                                Expr *LHS, Expr *RHS) {
725  assert(BinaryOperator::isAssignmentOp(opcode));
726
727  // If there's no setter, we have no choice but to try to assign to
728  // the result of the getter.
729  if (!findSetter()) {
730    ExprResult result;
731    if (tryBuildGetOfReference(LHS, result)) {
732      if (result.isInvalid()) return ExprError();
733      return S.BuildBinOp(Sc, opcLoc, opcode, result.take(), RHS);
734    }
735
736    // Otherwise, it's an error.
737    S.Diag(opcLoc, diag::err_nosetter_property_assignment)
738      << unsigned(RefExpr->isImplicitProperty())
739      << SetterSelector
740      << LHS->getSourceRange() << RHS->getSourceRange();
741    return ExprError();
742  }
743
744  // If there is a setter, we definitely want to use it.
745
746  // Verify that we can do a compound assignment.
747  if (opcode != BO_Assign && !findGetter()) {
748    S.Diag(opcLoc, diag::err_nogetter_property_compound_assignment)
749      << LHS->getSourceRange() << RHS->getSourceRange();
750    return ExprError();
751  }
752
753  ExprResult result =
754    PseudoOpBuilder::buildAssignmentOperation(Sc, opcLoc, opcode, LHS, RHS);
755  if (result.isInvalid()) return ExprError();
756
757  // Various warnings about property assignments in ARC.
758  if (S.getLangOpts().ObjCAutoRefCount && InstanceReceiver) {
759    S.checkRetainCycles(InstanceReceiver->getSourceExpr(), RHS);
760    S.checkUnsafeExprAssigns(opcLoc, LHS, RHS);
761  }
762
763  return result;
764}
765
766/// @property-specific behavior for doing increments and decrements.
767ExprResult
768ObjCPropertyOpBuilder::buildIncDecOperation(Scope *Sc, SourceLocation opcLoc,
769                                            UnaryOperatorKind opcode,
770                                            Expr *op) {
771  // If there's no setter, we have no choice but to try to assign to
772  // the result of the getter.
773  if (!findSetter()) {
774    ExprResult result;
775    if (tryBuildGetOfReference(op, result)) {
776      if (result.isInvalid()) return ExprError();
777      return S.BuildUnaryOp(Sc, opcLoc, opcode, result.take());
778    }
779
780    // Otherwise, it's an error.
781    S.Diag(opcLoc, diag::err_nosetter_property_incdec)
782      << unsigned(RefExpr->isImplicitProperty())
783      << unsigned(UnaryOperator::isDecrementOp(opcode))
784      << SetterSelector
785      << op->getSourceRange();
786    return ExprError();
787  }
788
789  // If there is a setter, we definitely want to use it.
790
791  // We also need a getter.
792  if (!findGetter()) {
793    assert(RefExpr->isImplicitProperty());
794    S.Diag(opcLoc, diag::err_nogetter_property_incdec)
795      << unsigned(UnaryOperator::isDecrementOp(opcode))
796      << GetterSelector
797      << op->getSourceRange();
798    return ExprError();
799  }
800
801  return PseudoOpBuilder::buildIncDecOperation(Sc, opcLoc, opcode, op);
802}
803
804// ObjCSubscript build stuff.
805//
806
807/// objective-c subscripting-specific behavior for doing lvalue-to-rvalue
808/// conversion.
809/// FIXME. Remove this routine if it is proven that no additional
810/// specifity is needed.
811ExprResult ObjCSubscriptOpBuilder::buildRValueOperation(Expr *op) {
812  ExprResult result = PseudoOpBuilder::buildRValueOperation(op);
813  if (result.isInvalid()) return ExprError();
814  return result;
815}
816
817/// objective-c subscripting-specific  behavior for doing assignments.
818ExprResult
819ObjCSubscriptOpBuilder::buildAssignmentOperation(Scope *Sc,
820                                                SourceLocation opcLoc,
821                                                BinaryOperatorKind opcode,
822                                                Expr *LHS, Expr *RHS) {
823  assert(BinaryOperator::isAssignmentOp(opcode));
824  // There must be a method to do the Index'ed assignment.
825  if (!findAtIndexSetter())
826    return ExprError();
827
828  // Verify that we can do a compound assignment.
829  if (opcode != BO_Assign && !findAtIndexGetter())
830    return ExprError();
831
832  ExprResult result =
833  PseudoOpBuilder::buildAssignmentOperation(Sc, opcLoc, opcode, LHS, RHS);
834  if (result.isInvalid()) return ExprError();
835
836  // Various warnings about objc Index'ed assignments in ARC.
837  if (S.getLangOpts().ObjCAutoRefCount && InstanceBase) {
838    S.checkRetainCycles(InstanceBase->getSourceExpr(), RHS);
839    S.checkUnsafeExprAssigns(opcLoc, LHS, RHS);
840  }
841
842  return result;
843}
844
845/// Capture the base object of an Objective-C Index'ed expression.
846Expr *ObjCSubscriptOpBuilder::rebuildAndCaptureObject(Expr *syntacticBase) {
847  assert(InstanceBase == 0);
848
849  // Capture base expression in an OVE and rebuild the syntactic
850  // form to use the OVE as its base expression.
851  InstanceBase = capture(RefExpr->getBaseExpr());
852  InstanceKey = capture(RefExpr->getKeyExpr());
853
854  syntacticBase =
855    ObjCSubscriptRefRebuilder(S, InstanceBase,
856                              InstanceKey).rebuild(syntacticBase);
857
858  return syntacticBase;
859}
860
861/// CheckSubscriptingKind - This routine decide what type
862/// of indexing represented by "FromE" is being done.
863Sema::ObjCSubscriptKind
864  Sema::CheckSubscriptingKind(Expr *FromE) {
865  // If the expression already has integral or enumeration type, we're golden.
866  QualType T = FromE->getType();
867  if (T->isIntegralOrEnumerationType())
868    return OS_Array;
869
870  // If we don't have a class type in C++, there's no way we can get an
871  // expression of integral or enumeration type.
872  const RecordType *RecordTy = T->getAs<RecordType>();
873  if (!RecordTy && T->isObjCObjectPointerType())
874    // All other scalar cases are assumed to be dictionary indexing which
875    // caller handles, with diagnostics if needed.
876    return OS_Dictionary;
877  if (!getLangOpts().CPlusPlus ||
878      !RecordTy || RecordTy->isIncompleteType()) {
879    // No indexing can be done. Issue diagnostics and quit.
880    const Expr *IndexExpr = FromE->IgnoreParenImpCasts();
881    if (isa<StringLiteral>(IndexExpr))
882      Diag(FromE->getExprLoc(), diag::err_objc_subscript_pointer)
883        << T << FixItHint::CreateInsertion(FromE->getExprLoc(), "@");
884    else
885      Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
886        << T;
887    return OS_Error;
888  }
889
890  // We must have a complete class type.
891  if (RequireCompleteType(FromE->getExprLoc(), T,
892                          PDiag(diag::err_objc_index_incomplete_class_type)
893                          << FromE->getSourceRange()))
894    return OS_Error;
895
896  // Look for a conversion to an integral, enumeration type, or
897  // objective-C pointer type.
898  UnresolvedSet<4> ViableConversions;
899  UnresolvedSet<4> ExplicitConversions;
900  const UnresolvedSetImpl *Conversions
901    = cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();
902
903  int NoIntegrals=0, NoObjCIdPointers=0;
904  SmallVector<CXXConversionDecl *, 4> ConversionDecls;
905
906  for (UnresolvedSetImpl::iterator I = Conversions->begin(),
907       E = Conversions->end();
908       I != E;
909       ++I) {
910    if (CXXConversionDecl *Conversion
911        = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) {
912      QualType CT = Conversion->getConversionType().getNonReferenceType();
913      if (CT->isIntegralOrEnumerationType()) {
914        ++NoIntegrals;
915        ConversionDecls.push_back(Conversion);
916      }
917      else if (CT->isObjCIdType() ||CT->isBlockPointerType()) {
918        ++NoObjCIdPointers;
919        ConversionDecls.push_back(Conversion);
920      }
921    }
922  }
923  if (NoIntegrals ==1 && NoObjCIdPointers == 0)
924    return OS_Array;
925  if (NoIntegrals == 0 && NoObjCIdPointers == 1)
926    return OS_Dictionary;
927  if (NoIntegrals == 0 && NoObjCIdPointers == 0) {
928    // No conversion function was found. Issue diagnostic and return.
929    Diag(FromE->getExprLoc(), diag::err_objc_subscript_type_conversion)
930      << FromE->getType();
931    return OS_Error;
932  }
933  Diag(FromE->getExprLoc(), diag::err_objc_multiple_subscript_type_conversion)
934      << FromE->getType();
935  for (unsigned int i = 0; i < ConversionDecls.size(); i++)
936    Diag(ConversionDecls[i]->getLocation(), diag::not_conv_function_declared_at);
937
938  return OS_Error;
939}
940
941bool ObjCSubscriptOpBuilder::findAtIndexGetter() {
942  if (AtIndexGetter)
943    return true;
944
945  Expr *BaseExpr = RefExpr->getBaseExpr();
946  QualType BaseT = BaseExpr->getType();
947
948  QualType ResultType;
949  if (const ObjCObjectPointerType *PTy =
950      BaseT->getAs<ObjCObjectPointerType>()) {
951    ResultType = PTy->getPointeeType();
952    if (const ObjCObjectType *iQFaceTy =
953        ResultType->getAsObjCQualifiedInterfaceType())
954      ResultType = iQFaceTy->getBaseType();
955  }
956  Sema::ObjCSubscriptKind Res =
957    S.CheckSubscriptingKind(RefExpr->getKeyExpr());
958  if (Res == Sema::OS_Error)
959    return false;
960  bool arrayRef = (Res == Sema::OS_Array);
961
962  if (ResultType.isNull()) {
963    S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
964      << BaseExpr->getType() << arrayRef;
965    return false;
966  }
967  if (!arrayRef) {
968    // dictionary subscripting.
969    // - (id)objectForKeyedSubscript:(id)key;
970    IdentifierInfo *KeyIdents[] = {
971      &S.Context.Idents.get("objectForKeyedSubscript")
972    };
973    AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
974  }
975  else {
976    // - (id)objectAtIndexedSubscript:(size_t)index;
977    IdentifierInfo *KeyIdents[] = {
978      &S.Context.Idents.get("objectAtIndexedSubscript")
979    };
980
981    AtIndexGetterSelector = S.Context.Selectors.getSelector(1, KeyIdents);
982  }
983
984  AtIndexGetter = S.LookupMethodInObjectType(AtIndexGetterSelector, ResultType,
985                                             true /*instance*/);
986  bool receiverIdType = (BaseT->isObjCIdType() ||
987                         BaseT->isObjCQualifiedIdType());
988
989  if (!AtIndexGetter && S.getLangOpts().DebuggerObjCLiteral) {
990    AtIndexGetter = ObjCMethodDecl::Create(S.Context, SourceLocation(),
991                           SourceLocation(), AtIndexGetterSelector,
992                           S.Context.getObjCIdType() /*ReturnType*/,
993                           0 /*TypeSourceInfo */,
994                           S.Context.getTranslationUnitDecl(),
995                           true /*Instance*/, false/*isVariadic*/,
996                           /*isSynthesized=*/false,
997                           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
998                           ObjCMethodDecl::Required,
999                           false);
1000    ParmVarDecl *Argument = ParmVarDecl::Create(S.Context, AtIndexGetter,
1001                                                SourceLocation(), SourceLocation(),
1002                                                arrayRef ? &S.Context.Idents.get("index")
1003                                                         : &S.Context.Idents.get("key"),
1004                                                arrayRef ? S.Context.UnsignedLongTy
1005                                                         : S.Context.getObjCIdType(),
1006                                                /*TInfo=*/0,
1007                                                SC_None,
1008                                                SC_None,
1009                                                0);
1010    AtIndexGetter->setMethodParams(S.Context, Argument,
1011                                   ArrayRef<SourceLocation>());
1012  }
1013
1014  if (!AtIndexGetter) {
1015    if (!receiverIdType) {
1016      S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_method_not_found)
1017      << BaseExpr->getType() << 0 << arrayRef;
1018      return false;
1019    }
1020    AtIndexGetter =
1021      S.LookupInstanceMethodInGlobalPool(AtIndexGetterSelector,
1022                                         RefExpr->getSourceRange(),
1023                                         true, false);
1024  }
1025
1026  if (AtIndexGetter) {
1027    QualType T = AtIndexGetter->param_begin()[0]->getType();
1028    if ((arrayRef && !T->isIntegralOrEnumerationType()) ||
1029        (!arrayRef && !T->isObjCObjectPointerType())) {
1030      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1031             arrayRef ? diag::err_objc_subscript_index_type
1032                      : diag::err_objc_subscript_key_type) << T;
1033      S.Diag(AtIndexGetter->param_begin()[0]->getLocation(),
1034             diag::note_parameter_type) << T;
1035      return false;
1036    }
1037    QualType R = AtIndexGetter->getResultType();
1038    if (!R->isObjCObjectPointerType()) {
1039      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1040             diag::err_objc_indexing_method_result_type) << R << arrayRef;
1041      S.Diag(AtIndexGetter->getLocation(), diag::note_method_declared_at) <<
1042        AtIndexGetter->getDeclName();
1043    }
1044  }
1045  return true;
1046}
1047
1048bool ObjCSubscriptOpBuilder::findAtIndexSetter() {
1049  if (AtIndexSetter)
1050    return true;
1051
1052  Expr *BaseExpr = RefExpr->getBaseExpr();
1053  QualType BaseT = BaseExpr->getType();
1054
1055  QualType ResultType;
1056  if (const ObjCObjectPointerType *PTy =
1057      BaseT->getAs<ObjCObjectPointerType>()) {
1058    ResultType = PTy->getPointeeType();
1059    if (const ObjCObjectType *iQFaceTy =
1060        ResultType->getAsObjCQualifiedInterfaceType())
1061      ResultType = iQFaceTy->getBaseType();
1062  }
1063
1064  Sema::ObjCSubscriptKind Res =
1065    S.CheckSubscriptingKind(RefExpr->getKeyExpr());
1066  if (Res == Sema::OS_Error)
1067    return false;
1068  bool arrayRef = (Res == Sema::OS_Array);
1069
1070  if (ResultType.isNull()) {
1071    S.Diag(BaseExpr->getExprLoc(), diag::err_objc_subscript_base_type)
1072      << BaseExpr->getType() << arrayRef;
1073    return false;
1074  }
1075
1076  if (!arrayRef) {
1077    // dictionary subscripting.
1078    // - (void)setObject:(id)object forKeyedSubscript:(id)key;
1079    IdentifierInfo *KeyIdents[] = {
1080      &S.Context.Idents.get("setObject"),
1081      &S.Context.Idents.get("forKeyedSubscript")
1082    };
1083    AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
1084  }
1085  else {
1086    // - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
1087    IdentifierInfo *KeyIdents[] = {
1088      &S.Context.Idents.get("setObject"),
1089      &S.Context.Idents.get("atIndexedSubscript")
1090    };
1091    AtIndexSetterSelector = S.Context.Selectors.getSelector(2, KeyIdents);
1092  }
1093  AtIndexSetter = S.LookupMethodInObjectType(AtIndexSetterSelector, ResultType,
1094                                             true /*instance*/);
1095
1096  bool receiverIdType = (BaseT->isObjCIdType() ||
1097                         BaseT->isObjCQualifiedIdType());
1098
1099  if (!AtIndexSetter && S.getLangOpts().DebuggerObjCLiteral) {
1100    TypeSourceInfo *ResultTInfo = 0;
1101    QualType ReturnType = S.Context.VoidTy;
1102    AtIndexSetter = ObjCMethodDecl::Create(S.Context, SourceLocation(),
1103                           SourceLocation(), AtIndexSetterSelector,
1104                           ReturnType,
1105                           ResultTInfo,
1106                           S.Context.getTranslationUnitDecl(),
1107                           true /*Instance*/, false/*isVariadic*/,
1108                           /*isSynthesized=*/false,
1109                           /*isImplicitlyDeclared=*/true, /*isDefined=*/false,
1110                           ObjCMethodDecl::Required,
1111                           false);
1112    SmallVector<ParmVarDecl *, 2> Params;
1113    ParmVarDecl *object = ParmVarDecl::Create(S.Context, AtIndexSetter,
1114                                                SourceLocation(), SourceLocation(),
1115                                                &S.Context.Idents.get("object"),
1116                                                S.Context.getObjCIdType(),
1117                                                /*TInfo=*/0,
1118                                                SC_None,
1119                                                SC_None,
1120                                                0);
1121    Params.push_back(object);
1122    ParmVarDecl *key = ParmVarDecl::Create(S.Context, AtIndexSetter,
1123                                                SourceLocation(), SourceLocation(),
1124                                                arrayRef ?  &S.Context.Idents.get("index")
1125                                                         :  &S.Context.Idents.get("key"),
1126                                                arrayRef ? S.Context.UnsignedLongTy
1127                                                         : S.Context.getObjCIdType(),
1128                                                /*TInfo=*/0,
1129                                                SC_None,
1130                                                SC_None,
1131                                                0);
1132    Params.push_back(key);
1133    AtIndexSetter->setMethodParams(S.Context, Params, ArrayRef<SourceLocation>());
1134  }
1135
1136  if (!AtIndexSetter) {
1137    if (!receiverIdType) {
1138      S.Diag(BaseExpr->getExprLoc(),
1139             diag::err_objc_subscript_method_not_found)
1140      << BaseExpr->getType() << 1 << arrayRef;
1141      return false;
1142    }
1143    AtIndexSetter =
1144      S.LookupInstanceMethodInGlobalPool(AtIndexSetterSelector,
1145                                         RefExpr->getSourceRange(),
1146                                         true, false);
1147  }
1148
1149  bool err = false;
1150  if (AtIndexSetter && arrayRef) {
1151    QualType T = AtIndexSetter->param_begin()[1]->getType();
1152    if (!T->isIntegralOrEnumerationType()) {
1153      S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1154             diag::err_objc_subscript_index_type) << T;
1155      S.Diag(AtIndexSetter->param_begin()[1]->getLocation(),
1156             diag::note_parameter_type) << T;
1157      err = true;
1158    }
1159    T = AtIndexSetter->param_begin()[0]->getType();
1160    if (!T->isObjCObjectPointerType()) {
1161      S.Diag(RefExpr->getBaseExpr()->getExprLoc(),
1162             diag::err_objc_subscript_object_type) << T << arrayRef;
1163      S.Diag(AtIndexSetter->param_begin()[0]->getLocation(),
1164             diag::note_parameter_type) << T;
1165      err = true;
1166    }
1167  }
1168  else if (AtIndexSetter && !arrayRef)
1169    for (unsigned i=0; i <2; i++) {
1170      QualType T = AtIndexSetter->param_begin()[i]->getType();
1171      if (!T->isObjCObjectPointerType()) {
1172        if (i == 1)
1173          S.Diag(RefExpr->getKeyExpr()->getExprLoc(),
1174                 diag::err_objc_subscript_key_type) << T;
1175        else
1176          S.Diag(RefExpr->getBaseExpr()->getExprLoc(),
1177                 diag::err_objc_subscript_dic_object_type) << T;
1178        S.Diag(AtIndexSetter->param_begin()[i]->getLocation(),
1179               diag::note_parameter_type) << T;
1180        err = true;
1181      }
1182    }
1183
1184  return !err;
1185}
1186
1187// Get the object at "Index" position in the container.
1188// [BaseExpr objectAtIndexedSubscript : IndexExpr];
1189ExprResult ObjCSubscriptOpBuilder::buildGet() {
1190  if (!findAtIndexGetter())
1191    return ExprError();
1192
1193  QualType receiverType = InstanceBase->getType();
1194
1195  // Build a message-send.
1196  ExprResult msg;
1197  Expr *Index = InstanceKey;
1198
1199  // Arguments.
1200  Expr *args[] = { Index };
1201  assert(InstanceBase);
1202  msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
1203                                       GenericLoc,
1204                                       AtIndexGetterSelector, AtIndexGetter,
1205                                       MultiExprArg(args, 1));
1206  return msg;
1207}
1208
1209/// Store into the container the "op" object at "Index"'ed location
1210/// by building this messaging expression:
1211/// - (void)setObject:(id)object atIndexedSubscript:(NSInteger)index;
1212/// \param bindSetValueAsResult - If true, capture the actual
1213///   value being set as the value of the property operation.
1214ExprResult ObjCSubscriptOpBuilder::buildSet(Expr *op, SourceLocation opcLoc,
1215                                           bool captureSetValueAsResult) {
1216  if (!findAtIndexSetter())
1217    return ExprError();
1218
1219  QualType receiverType = InstanceBase->getType();
1220  Expr *Index = InstanceKey;
1221
1222  // Arguments.
1223  Expr *args[] = { op, Index };
1224
1225  // Build a message-send.
1226  ExprResult msg = S.BuildInstanceMessageImplicit(InstanceBase, receiverType,
1227                                                  GenericLoc,
1228                                                  AtIndexSetterSelector,
1229                                                  AtIndexSetter,
1230                                                  MultiExprArg(args, 2));
1231
1232  if (!msg.isInvalid() && captureSetValueAsResult) {
1233    ObjCMessageExpr *msgExpr =
1234      cast<ObjCMessageExpr>(msg.get()->IgnoreImplicit());
1235    Expr *arg = msgExpr->getArg(0);
1236    msgExpr->setArg(0, captureValueAsResult(arg));
1237  }
1238
1239  return msg;
1240}
1241
1242//===----------------------------------------------------------------------===//
1243//  General Sema routines.
1244//===----------------------------------------------------------------------===//
1245
1246ExprResult Sema::checkPseudoObjectRValue(Expr *E) {
1247  Expr *opaqueRef = E->IgnoreParens();
1248  if (ObjCPropertyRefExpr *refExpr
1249        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1250    ObjCPropertyOpBuilder builder(*this, refExpr);
1251    return builder.buildRValueOperation(E);
1252  }
1253  else if (ObjCSubscriptRefExpr *refExpr
1254           = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1255    ObjCSubscriptOpBuilder builder(*this, refExpr);
1256    return builder.buildRValueOperation(E);
1257  } else {
1258    llvm_unreachable("unknown pseudo-object kind!");
1259  }
1260}
1261
1262/// Check an increment or decrement of a pseudo-object expression.
1263ExprResult Sema::checkPseudoObjectIncDec(Scope *Sc, SourceLocation opcLoc,
1264                                         UnaryOperatorKind opcode, Expr *op) {
1265  // Do nothing if the operand is dependent.
1266  if (op->isTypeDependent())
1267    return new (Context) UnaryOperator(op, opcode, Context.DependentTy,
1268                                       VK_RValue, OK_Ordinary, opcLoc);
1269
1270  assert(UnaryOperator::isIncrementDecrementOp(opcode));
1271  Expr *opaqueRef = op->IgnoreParens();
1272  if (ObjCPropertyRefExpr *refExpr
1273        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1274    ObjCPropertyOpBuilder builder(*this, refExpr);
1275    return builder.buildIncDecOperation(Sc, opcLoc, opcode, op);
1276  } else if (isa<ObjCSubscriptRefExpr>(opaqueRef)) {
1277    Diag(opcLoc, diag::err_illegal_container_subscripting_op);
1278    return ExprError();
1279  } else {
1280    llvm_unreachable("unknown pseudo-object kind!");
1281  }
1282}
1283
1284ExprResult Sema::checkPseudoObjectAssignment(Scope *S, SourceLocation opcLoc,
1285                                             BinaryOperatorKind opcode,
1286                                             Expr *LHS, Expr *RHS) {
1287  // Do nothing if either argument is dependent.
1288  if (LHS->isTypeDependent() || RHS->isTypeDependent())
1289    return new (Context) BinaryOperator(LHS, RHS, opcode, Context.DependentTy,
1290                                        VK_RValue, OK_Ordinary, opcLoc);
1291
1292  // Filter out non-overload placeholder types in the RHS.
1293  if (RHS->getType()->isNonOverloadPlaceholderType()) {
1294    ExprResult result = CheckPlaceholderExpr(RHS);
1295    if (result.isInvalid()) return ExprError();
1296    RHS = result.take();
1297  }
1298
1299  Expr *opaqueRef = LHS->IgnoreParens();
1300  if (ObjCPropertyRefExpr *refExpr
1301        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1302    ObjCPropertyOpBuilder builder(*this, refExpr);
1303    return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
1304  } else if (ObjCSubscriptRefExpr *refExpr
1305             = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1306    ObjCSubscriptOpBuilder builder(*this, refExpr);
1307    return builder.buildAssignmentOperation(S, opcLoc, opcode, LHS, RHS);
1308  } else {
1309    llvm_unreachable("unknown pseudo-object kind!");
1310  }
1311}
1312
1313/// Given a pseudo-object reference, rebuild it without the opaque
1314/// values.  Basically, undo the behavior of rebuildAndCaptureObject.
1315/// This should never operate in-place.
1316static Expr *stripOpaqueValuesFromPseudoObjectRef(Sema &S, Expr *E) {
1317  Expr *opaqueRef = E->IgnoreParens();
1318  if (ObjCPropertyRefExpr *refExpr
1319        = dyn_cast<ObjCPropertyRefExpr>(opaqueRef)) {
1320    // Class and super property references don't have opaque values in them.
1321    if (refExpr->isClassReceiver() || refExpr->isSuperReceiver())
1322      return E;
1323
1324    assert(refExpr->isObjectReceiver() && "Unknown receiver kind?");
1325    OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBase());
1326    return ObjCPropertyRefRebuilder(S, baseOVE->getSourceExpr()).rebuild(E);
1327  } else if (ObjCSubscriptRefExpr *refExpr
1328               = dyn_cast<ObjCSubscriptRefExpr>(opaqueRef)) {
1329    OpaqueValueExpr *baseOVE = cast<OpaqueValueExpr>(refExpr->getBaseExpr());
1330    OpaqueValueExpr *keyOVE = cast<OpaqueValueExpr>(refExpr->getKeyExpr());
1331    return ObjCSubscriptRefRebuilder(S, baseOVE->getSourceExpr(),
1332                                     keyOVE->getSourceExpr()).rebuild(E);
1333  } else {
1334    llvm_unreachable("unknown pseudo-object kind!");
1335  }
1336}
1337
1338/// Given a pseudo-object expression, recreate what it looks like
1339/// syntactically without the attendant OpaqueValueExprs.
1340///
1341/// This is a hack which should be removed when TreeTransform is
1342/// capable of rebuilding a tree without stripping implicit
1343/// operations.
1344Expr *Sema::recreateSyntacticForm(PseudoObjectExpr *E) {
1345  Expr *syntax = E->getSyntacticForm();
1346  if (UnaryOperator *uop = dyn_cast<UnaryOperator>(syntax)) {
1347    Expr *op = stripOpaqueValuesFromPseudoObjectRef(*this, uop->getSubExpr());
1348    return new (Context) UnaryOperator(op, uop->getOpcode(), uop->getType(),
1349                                       uop->getValueKind(), uop->getObjectKind(),
1350                                       uop->getOperatorLoc());
1351  } else if (CompoundAssignOperator *cop
1352               = dyn_cast<CompoundAssignOperator>(syntax)) {
1353    Expr *lhs = stripOpaqueValuesFromPseudoObjectRef(*this, cop->getLHS());
1354    Expr *rhs = cast<OpaqueValueExpr>(cop->getRHS())->getSourceExpr();
1355    return new (Context) CompoundAssignOperator(lhs, rhs, cop->getOpcode(),
1356                                                cop->getType(),
1357                                                cop->getValueKind(),
1358                                                cop->getObjectKind(),
1359                                                cop->getComputationLHSType(),
1360                                                cop->getComputationResultType(),
1361                                                cop->getOperatorLoc());
1362  } else if (BinaryOperator *bop = dyn_cast<BinaryOperator>(syntax)) {
1363    Expr *lhs = stripOpaqueValuesFromPseudoObjectRef(*this, bop->getLHS());
1364    Expr *rhs = cast<OpaqueValueExpr>(bop->getRHS())->getSourceExpr();
1365    return new (Context) BinaryOperator(lhs, rhs, bop->getOpcode(),
1366                                        bop->getType(), bop->getValueKind(),
1367                                        bop->getObjectKind(),
1368                                        bop->getOperatorLoc());
1369  } else {
1370    assert(syntax->hasPlaceholderType(BuiltinType::PseudoObject));
1371    return stripOpaqueValuesFromPseudoObjectRef(*this, syntax);
1372  }
1373}
1374