clang  8.0.0
DynamicTypePropagation.cpp
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1 //===- DynamicTypePropagation.cpp ------------------------------*- C++ -*--===//
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 contains two checkers. One helps the static analyzer core to track
11 // types, the other does type inference on Obj-C generics and report type
12 // errors.
13 //
14 // Dynamic Type Propagation:
15 // This checker defines the rules for dynamic type gathering and propagation.
16 //
17 // Generics Checker for Objective-C:
18 // This checker tries to find type errors that the compiler is not able to catch
19 // due to the implicit conversions that were introduced for backward
20 // compatibility.
21 //
22 //===----------------------------------------------------------------------===//
23 
25 #include "clang/AST/ParentMap.h"
27 #include "clang/Basic/Builtins.h"
35 
36 using namespace clang;
37 using namespace ento;
38 
39 // ProgramState trait - The type inflation is tracked by DynamicTypeMap. This is
40 // an auxiliary map that tracks more information about generic types, because in
41 // some cases the most derived type is not the most informative one about the
42 // type parameters. This types that are stored for each symbol in this map must
43 // be specialized.
44 // TODO: In some case the type stored in this map is exactly the same that is
45 // stored in DynamicTypeMap. We should no store duplicated information in those
46 // cases.
47 REGISTER_MAP_WITH_PROGRAMSTATE(MostSpecializedTypeArgsMap, SymbolRef,
48  const ObjCObjectPointerType *)
49 
50 namespace {
51 class DynamicTypePropagation:
52  public Checker< check::PreCall,
53  check::PostCall,
54  check::DeadSymbols,
55  check::PostStmt<CastExpr>,
56  check::PostStmt<CXXNewExpr>,
57  check::PreObjCMessage,
58  check::PostObjCMessage > {
59  const ObjCObjectType *getObjectTypeForAllocAndNew(const ObjCMessageExpr *MsgE,
60  CheckerContext &C) const;
61 
62  /// Return a better dynamic type if one can be derived from the cast.
63  const ObjCObjectPointerType *getBetterObjCType(const Expr *CastE,
64  CheckerContext &C) const;
65 
66  ExplodedNode *dynamicTypePropagationOnCasts(const CastExpr *CE,
68  CheckerContext &C) const;
69 
70  mutable std::unique_ptr<BugType> ObjCGenericsBugType;
71  void initBugType() const {
72  if (!ObjCGenericsBugType)
73  ObjCGenericsBugType.reset(
74  new BugType(this, "Generics", categories::CoreFoundationObjectiveC));
75  }
76 
77  class GenericsBugVisitor : public BugReporterVisitor {
78  public:
79  GenericsBugVisitor(SymbolRef S) : Sym(S) {}
80 
81  void Profile(llvm::FoldingSetNodeID &ID) const override {
82  static int X = 0;
83  ID.AddPointer(&X);
84  ID.AddPointer(Sym);
85  }
86 
87  std::shared_ptr<PathDiagnosticPiece> VisitNode(const ExplodedNode *N,
88  BugReporterContext &BRC,
89  BugReport &BR) override;
90 
91  private:
92  // The tracked symbol.
93  SymbolRef Sym;
94  };
95 
96  void reportGenericsBug(const ObjCObjectPointerType *From,
97  const ObjCObjectPointerType *To, ExplodedNode *N,
98  SymbolRef Sym, CheckerContext &C,
99  const Stmt *ReportedNode = nullptr) const;
100 
101 public:
102  void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
103  void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
104  void checkPostStmt(const CastExpr *CastE, CheckerContext &C) const;
105  void checkPostStmt(const CXXNewExpr *NewE, CheckerContext &C) const;
106  void checkDeadSymbols(SymbolReaper &SR, CheckerContext &C) const;
107  void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const;
108  void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const;
109 
110  /// This value is set to true, when the Generics checker is turned on.
111  DefaultBool CheckGenerics;
112 };
113 } // end anonymous namespace
114 
115 void DynamicTypePropagation::checkDeadSymbols(SymbolReaper &SR,
116  CheckerContext &C) const {
117  ProgramStateRef State = C.getState();
118  DynamicTypeMapImpl TypeMap = State->get<DynamicTypeMap>();
119  for (DynamicTypeMapImpl::iterator I = TypeMap.begin(), E = TypeMap.end();
120  I != E; ++I) {
121  if (!SR.isLiveRegion(I->first)) {
122  State = State->remove<DynamicTypeMap>(I->first);
123  }
124  }
125 
126  MostSpecializedTypeArgsMapTy TyArgMap =
127  State->get<MostSpecializedTypeArgsMap>();
128  for (MostSpecializedTypeArgsMapTy::iterator I = TyArgMap.begin(),
129  E = TyArgMap.end();
130  I != E; ++I) {
131  if (SR.isDead(I->first)) {
132  State = State->remove<MostSpecializedTypeArgsMap>(I->first);
133  }
134  }
135 
136  C.addTransition(State);
137 }
138 
139 static void recordFixedType(const MemRegion *Region, const CXXMethodDecl *MD,
140  CheckerContext &C) {
141  assert(Region);
142  assert(MD);
143 
144  ASTContext &Ctx = C.getASTContext();
145  QualType Ty = Ctx.getPointerType(Ctx.getRecordType(MD->getParent()));
146 
147  ProgramStateRef State = C.getState();
148  State = setDynamicTypeInfo(State, Region, Ty, /*CanBeSubclass=*/false);
149  C.addTransition(State);
150 }
151 
152 void DynamicTypePropagation::checkPreCall(const CallEvent &Call,
153  CheckerContext &C) const {
154  if (const CXXConstructorCall *Ctor = dyn_cast<CXXConstructorCall>(&Call)) {
155  // C++11 [class.cdtor]p4: When a virtual function is called directly or
156  // indirectly from a constructor or from a destructor, including during
157  // the construction or destruction of the class's non-static data members,
158  // and the object to which the call applies is the object under
159  // construction or destruction, the function called is the final overrider
160  // in the constructor's or destructor's class and not one overriding it in
161  // a more-derived class.
162 
163  switch (Ctor->getOriginExpr()->getConstructionKind()) {
166  // No additional type info necessary.
167  return;
170  if (const MemRegion *Target = Ctor->getCXXThisVal().getAsRegion())
171  recordFixedType(Target, Ctor->getDecl(), C);
172  return;
173  }
174 
175  return;
176  }
177 
178  if (const CXXDestructorCall *Dtor = dyn_cast<CXXDestructorCall>(&Call)) {
179  // C++11 [class.cdtor]p4 (see above)
180  if (!Dtor->isBaseDestructor())
181  return;
182 
183  const MemRegion *Target = Dtor->getCXXThisVal().getAsRegion();
184  if (!Target)
185  return;
186 
187  const Decl *D = Dtor->getDecl();
188  if (!D)
189  return;
190 
191  recordFixedType(Target, cast<CXXDestructorDecl>(D), C);
192  return;
193  }
194 }
195 
196 void DynamicTypePropagation::checkPostCall(const CallEvent &Call,
197  CheckerContext &C) const {
198  // We can obtain perfect type info for return values from some calls.
199  if (const ObjCMethodCall *Msg = dyn_cast<ObjCMethodCall>(&Call)) {
200 
201  // Get the returned value if it's a region.
202  const MemRegion *RetReg = Call.getReturnValue().getAsRegion();
203  if (!RetReg)
204  return;
205 
206  ProgramStateRef State = C.getState();
207  const ObjCMethodDecl *D = Msg->getDecl();
208 
209  if (D && D->hasRelatedResultType()) {
210  switch (Msg->getMethodFamily()) {
211  default:
212  break;
213 
214  // We assume that the type of the object returned by alloc and new are the
215  // pointer to the object of the class specified in the receiver of the
216  // message.
217  case OMF_alloc:
218  case OMF_new: {
219  // Get the type of object that will get created.
220  const ObjCMessageExpr *MsgE = Msg->getOriginExpr();
221  const ObjCObjectType *ObjTy = getObjectTypeForAllocAndNew(MsgE, C);
222  if (!ObjTy)
223  return;
224  QualType DynResTy =
225  C.getASTContext().getObjCObjectPointerType(QualType(ObjTy, 0));
226  C.addTransition(setDynamicTypeInfo(State, RetReg, DynResTy, false));
227  break;
228  }
229  case OMF_init: {
230  // Assume, the result of the init method has the same dynamic type as
231  // the receiver and propagate the dynamic type info.
232  const MemRegion *RecReg = Msg->getReceiverSVal().getAsRegion();
233  if (!RecReg)
234  return;
235  DynamicTypeInfo RecDynType = getDynamicTypeInfo(State, RecReg);
236  C.addTransition(setDynamicTypeInfo(State, RetReg, RecDynType));
237  break;
238  }
239  }
240  }
241  return;
242  }
243 
244  if (const CXXConstructorCall *Ctor = dyn_cast<CXXConstructorCall>(&Call)) {
245  // We may need to undo the effects of our pre-call check.
246  switch (Ctor->getOriginExpr()->getConstructionKind()) {
249  // No additional work necessary.
250  // Note: This will leave behind the actual type of the object for
251  // complete constructors, but arguably that's a good thing, since it
252  // means the dynamic type info will be correct even for objects
253  // constructed with operator new.
254  return;
257  if (const MemRegion *Target = Ctor->getCXXThisVal().getAsRegion()) {
258  // We just finished a base constructor. Now we can use the subclass's
259  // type when resolving virtual calls.
260  const LocationContext *LCtx = C.getLocationContext();
261 
262  // FIXME: In C++17 classes with non-virtual bases may be treated as
263  // aggregates, and in such case no top-frame constructor will be called.
264  // Figure out if we need to do anything in this case.
265  // FIXME: Instead of relying on the ParentMap, we should have the
266  // trigger-statement (InitListExpr in this case) available in this
267  // callback, ideally as part of CallEvent.
268  if (dyn_cast_or_null<InitListExpr>(
269  LCtx->getParentMap().getParent(Ctor->getOriginExpr())))
270  return;
271 
272  recordFixedType(Target, cast<CXXConstructorDecl>(LCtx->getDecl()), C);
273  }
274  return;
275  }
276  }
277 }
278 
279 /// TODO: Handle explicit casts.
280 /// Handle C++ casts.
281 ///
282 /// Precondition: the cast is between ObjCObjectPointers.
283 ExplodedNode *DynamicTypePropagation::dynamicTypePropagationOnCasts(
284  const CastExpr *CE, ProgramStateRef &State, CheckerContext &C) const {
285  // We only track type info for regions.
286  const MemRegion *ToR = C.getSVal(CE).getAsRegion();
287  if (!ToR)
288  return C.getPredecessor();
289 
290  if (isa<ExplicitCastExpr>(CE))
291  return C.getPredecessor();
292 
293  if (const Type *NewTy = getBetterObjCType(CE, C)) {
294  State = setDynamicTypeInfo(State, ToR, QualType(NewTy, 0));
295  return C.addTransition(State);
296  }
297  return C.getPredecessor();
298 }
299 
300 void DynamicTypePropagation::checkPostStmt(const CXXNewExpr *NewE,
301  CheckerContext &C) const {
302  if (NewE->isArray())
303  return;
304 
305  // We only track dynamic type info for regions.
306  const MemRegion *MR = C.getSVal(NewE).getAsRegion();
307  if (!MR)
308  return;
309 
310  C.addTransition(setDynamicTypeInfo(C.getState(), MR, NewE->getType(),
311  /*CanBeSubclass=*/false));
312 }
313 
314 const ObjCObjectType *
315 DynamicTypePropagation::getObjectTypeForAllocAndNew(const ObjCMessageExpr *MsgE,
316  CheckerContext &C) const {
317  if (MsgE->getReceiverKind() == ObjCMessageExpr::Class) {
318  if (const ObjCObjectType *ObjTy
319  = MsgE->getClassReceiver()->getAs<ObjCObjectType>())
320  return ObjTy;
321  }
322 
324  if (const ObjCObjectType *ObjTy
325  = MsgE->getSuperType()->getAs<ObjCObjectType>())
326  return ObjTy;
327  }
328 
329  const Expr *RecE = MsgE->getInstanceReceiver();
330  if (!RecE)
331  return nullptr;
332 
333  RecE= RecE->IgnoreParenImpCasts();
334  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(RecE)) {
335  const StackFrameContext *SFCtx = C.getStackFrame();
336  // Are we calling [self alloc]? If this is self, get the type of the
337  // enclosing ObjC class.
338  if (DRE->getDecl() == SFCtx->getSelfDecl()) {
339  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(SFCtx->getDecl()))
340  if (const ObjCObjectType *ObjTy =
341  dyn_cast<ObjCObjectType>(MD->getClassInterface()->getTypeForDecl()))
342  return ObjTy;
343  }
344  }
345  return nullptr;
346 }
347 
348 // Return a better dynamic type if one can be derived from the cast.
349 // Compare the current dynamic type of the region and the new type to which we
350 // are casting. If the new type is lower in the inheritance hierarchy, pick it.
351 const ObjCObjectPointerType *
352 DynamicTypePropagation::getBetterObjCType(const Expr *CastE,
353  CheckerContext &C) const {
354  const MemRegion *ToR = C.getSVal(CastE).getAsRegion();
355  assert(ToR);
356 
357  // Get the old and new types.
358  const ObjCObjectPointerType *NewTy =
359  CastE->getType()->getAs<ObjCObjectPointerType>();
360  if (!NewTy)
361  return nullptr;
362  QualType OldDTy = getDynamicTypeInfo(C.getState(), ToR).getType();
363  if (OldDTy.isNull()) {
364  return NewTy;
365  }
366  const ObjCObjectPointerType *OldTy =
367  OldDTy->getAs<ObjCObjectPointerType>();
368  if (!OldTy)
369  return nullptr;
370 
371  // Id the old type is 'id', the new one is more precise.
372  if (OldTy->isObjCIdType() && !NewTy->isObjCIdType())
373  return NewTy;
374 
375  // Return new if it's a subclass of old.
376  const ObjCInterfaceDecl *ToI = NewTy->getInterfaceDecl();
377  const ObjCInterfaceDecl *FromI = OldTy->getInterfaceDecl();
378  if (ToI && FromI && FromI->isSuperClassOf(ToI))
379  return NewTy;
380 
381  return nullptr;
382 }
383 
385  const ObjCObjectPointerType *From, const ObjCObjectPointerType *To,
386  const ObjCObjectPointerType *MostInformativeCandidate, ASTContext &C) {
387  // Checking if from and to are the same classes modulo specialization.
388  if (From->getInterfaceDecl()->getCanonicalDecl() ==
390  if (To->isSpecialized()) {
391  assert(MostInformativeCandidate->isSpecialized());
392  return MostInformativeCandidate;
393  }
394  return From;
395  }
396 
397  if (To->getObjectType()->getSuperClassType().isNull()) {
398  // If To has no super class and From and To aren't the same then
399  // To was not actually a descendent of From. In this case the best we can
400  // do is 'From'.
401  return From;
402  }
403 
404  const auto *SuperOfTo =
406  assert(SuperOfTo);
407  QualType SuperPtrOfToQual =
408  C.getObjCObjectPointerType(QualType(SuperOfTo, 0));
409  const auto *SuperPtrOfTo = SuperPtrOfToQual->getAs<ObjCObjectPointerType>();
410  if (To->isUnspecialized())
411  return getMostInformativeDerivedClassImpl(From, SuperPtrOfTo, SuperPtrOfTo,
412  C);
413  else
414  return getMostInformativeDerivedClassImpl(From, SuperPtrOfTo,
415  MostInformativeCandidate, C);
416 }
417 
418 /// A downcast may loose specialization information. E. g.:
419 /// MutableMap<T, U> : Map
420 /// The downcast to MutableMap looses the information about the types of the
421 /// Map (due to the type parameters are not being forwarded to Map), and in
422 /// general there is no way to recover that information from the
423 /// declaration. In order to have to most information, lets find the most
424 /// derived type that has all the type parameters forwarded.
425 ///
426 /// Get the a subclass of \p From (which has a lower bound \p To) that do not
427 /// loose information about type parameters. \p To has to be a subclass of
428 /// \p From. From has to be specialized.
429 static const ObjCObjectPointerType *
431  const ObjCObjectPointerType *To, ASTContext &C) {
432  return getMostInformativeDerivedClassImpl(From, To, To, C);
433 }
434 
435 /// Inputs:
436 /// \param StaticLowerBound Static lower bound for a symbol. The dynamic lower
437 /// bound might be the subclass of this type.
438 /// \param StaticUpperBound A static upper bound for a symbol.
439 /// \p StaticLowerBound expected to be the subclass of \p StaticUpperBound.
440 /// \param Current The type that was inferred for a symbol in a previous
441 /// context. Might be null when this is the first time that inference happens.
442 /// Precondition:
443 /// \p StaticLowerBound or \p StaticUpperBound is specialized. If \p Current
444 /// is not null, it is specialized.
445 /// Possible cases:
446 /// (1) The \p Current is null and \p StaticLowerBound <: \p StaticUpperBound
447 /// (2) \p StaticLowerBound <: \p Current <: \p StaticUpperBound
448 /// (3) \p Current <: \p StaticLowerBound <: \p StaticUpperBound
449 /// (4) \p StaticLowerBound <: \p StaticUpperBound <: \p Current
450 /// Effect:
451 /// Use getMostInformativeDerivedClass with the upper and lower bound of the
452 /// set {\p StaticLowerBound, \p Current, \p StaticUpperBound}. The computed
453 /// lower bound must be specialized. If the result differs from \p Current or
454 /// \p Current is null, store the result.
455 static bool
457  const ObjCObjectPointerType *const *Current,
458  const ObjCObjectPointerType *StaticLowerBound,
459  const ObjCObjectPointerType *StaticUpperBound,
460  ASTContext &C) {
461  // TODO: The above 4 cases are not exhaustive. In particular, it is possible
462  // for Current to be incomparable with StaticLowerBound, StaticUpperBound,
463  // or both.
464  //
465  // For example, suppose Foo<T> and Bar<T> are unrelated types.
466  //
467  // Foo<T> *f = ...
468  // Bar<T> *b = ...
469  //
470  // id t1 = b;
471  // f = t1;
472  // id t2 = f; // StaticLowerBound is Foo<T>, Current is Bar<T>
473  //
474  // We should either constrain the callers of this function so that the stated
475  // preconditions hold (and assert it) or rewrite the function to expicitly
476  // handle the additional cases.
477 
478  // Precondition
479  assert(StaticUpperBound->isSpecialized() ||
480  StaticLowerBound->isSpecialized());
481  assert(!Current || (*Current)->isSpecialized());
482 
483  // Case (1)
484  if (!Current) {
485  if (StaticUpperBound->isUnspecialized()) {
486  State = State->set<MostSpecializedTypeArgsMap>(Sym, StaticLowerBound);
487  return true;
488  }
489  // Upper bound is specialized.
490  const ObjCObjectPointerType *WithMostInfo =
491  getMostInformativeDerivedClass(StaticUpperBound, StaticLowerBound, C);
492  State = State->set<MostSpecializedTypeArgsMap>(Sym, WithMostInfo);
493  return true;
494  }
495 
496  // Case (3)
497  if (C.canAssignObjCInterfaces(StaticLowerBound, *Current)) {
498  return false;
499  }
500 
501  // Case (4)
502  if (C.canAssignObjCInterfaces(*Current, StaticUpperBound)) {
503  // The type arguments might not be forwarded at any point of inheritance.
504  const ObjCObjectPointerType *WithMostInfo =
505  getMostInformativeDerivedClass(*Current, StaticUpperBound, C);
506  WithMostInfo =
507  getMostInformativeDerivedClass(WithMostInfo, StaticLowerBound, C);
508  if (WithMostInfo == *Current)
509  return false;
510  State = State->set<MostSpecializedTypeArgsMap>(Sym, WithMostInfo);
511  return true;
512  }
513 
514  // Case (2)
515  const ObjCObjectPointerType *WithMostInfo =
516  getMostInformativeDerivedClass(*Current, StaticLowerBound, C);
517  if (WithMostInfo != *Current) {
518  State = State->set<MostSpecializedTypeArgsMap>(Sym, WithMostInfo);
519  return true;
520  }
521 
522  return false;
523 }
524 
525 /// Type inference based on static type information that is available for the
526 /// cast and the tracked type information for the given symbol. When the tracked
527 /// symbol and the destination type of the cast are unrelated, report an error.
528 void DynamicTypePropagation::checkPostStmt(const CastExpr *CE,
529  CheckerContext &C) const {
530  if (CE->getCastKind() != CK_BitCast)
531  return;
532 
533  QualType OriginType = CE->getSubExpr()->getType();
534  QualType DestType = CE->getType();
535 
536  const auto *OrigObjectPtrType = OriginType->getAs<ObjCObjectPointerType>();
537  const auto *DestObjectPtrType = DestType->getAs<ObjCObjectPointerType>();
538 
539  if (!OrigObjectPtrType || !DestObjectPtrType)
540  return;
541 
542  ProgramStateRef State = C.getState();
543  ExplodedNode *AfterTypeProp = dynamicTypePropagationOnCasts(CE, State, C);
544 
545  ASTContext &ASTCtxt = C.getASTContext();
546 
547  // This checker detects the subtyping relationships using the assignment
548  // rules. In order to be able to do this the kindofness must be stripped
549  // first. The checker treats every type as kindof type anyways: when the
550  // tracked type is the subtype of the static type it tries to look up the
551  // methods in the tracked type first.
552  OrigObjectPtrType = OrigObjectPtrType->stripObjCKindOfTypeAndQuals(ASTCtxt);
553  DestObjectPtrType = DestObjectPtrType->stripObjCKindOfTypeAndQuals(ASTCtxt);
554 
555  if (OrigObjectPtrType->isUnspecialized() &&
556  DestObjectPtrType->isUnspecialized())
557  return;
558 
559  SymbolRef Sym = C.getSVal(CE).getAsSymbol();
560  if (!Sym)
561  return;
562 
563  const ObjCObjectPointerType *const *TrackedType =
564  State->get<MostSpecializedTypeArgsMap>(Sym);
565 
566  if (isa<ExplicitCastExpr>(CE)) {
567  // Treat explicit casts as an indication from the programmer that the
568  // Objective-C type system is not rich enough to express the needed
569  // invariant. In such cases, forget any existing information inferred
570  // about the type arguments. We don't assume the casted-to specialized
571  // type here because the invariant the programmer specifies in the cast
572  // may only hold at this particular program point and not later ones.
573  // We don't want a suppressing cast to require a cascade of casts down the
574  // line.
575  if (TrackedType) {
576  State = State->remove<MostSpecializedTypeArgsMap>(Sym);
577  C.addTransition(State, AfterTypeProp);
578  }
579  return;
580  }
581 
582  // Check which assignments are legal.
583  bool OrigToDest =
584  ASTCtxt.canAssignObjCInterfaces(DestObjectPtrType, OrigObjectPtrType);
585  bool DestToOrig =
586  ASTCtxt.canAssignObjCInterfaces(OrigObjectPtrType, DestObjectPtrType);
587 
588  // The tracked type should be the sub or super class of the static destination
589  // type. When an (implicit) upcast or a downcast happens according to static
590  // types, and there is no subtyping relationship between the tracked and the
591  // static destination types, it indicates an error.
592  if (TrackedType &&
593  !ASTCtxt.canAssignObjCInterfaces(DestObjectPtrType, *TrackedType) &&
594  !ASTCtxt.canAssignObjCInterfaces(*TrackedType, DestObjectPtrType)) {
595  static CheckerProgramPointTag IllegalConv(this, "IllegalConversion");
596  ExplodedNode *N = C.addTransition(State, AfterTypeProp, &IllegalConv);
597  reportGenericsBug(*TrackedType, DestObjectPtrType, N, Sym, C);
598  return;
599  }
600 
601  // Handle downcasts and upcasts.
602 
603  const ObjCObjectPointerType *LowerBound = DestObjectPtrType;
604  const ObjCObjectPointerType *UpperBound = OrigObjectPtrType;
605  if (OrigToDest && !DestToOrig)
606  std::swap(LowerBound, UpperBound);
607 
608  // The id type is not a real bound. Eliminate it.
609  LowerBound = LowerBound->isObjCIdType() ? UpperBound : LowerBound;
610  UpperBound = UpperBound->isObjCIdType() ? LowerBound : UpperBound;
611 
612  if (storeWhenMoreInformative(State, Sym, TrackedType, LowerBound, UpperBound,
613  ASTCtxt)) {
614  C.addTransition(State, AfterTypeProp);
615  }
616 }
617 
618 static const Expr *stripCastsAndSugar(const Expr *E) {
619  E = E->IgnoreParenImpCasts();
620  if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E))
621  E = POE->getSyntacticForm()->IgnoreParenImpCasts();
622  if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E))
623  E = OVE->getSourceExpr()->IgnoreParenImpCasts();
624  return E;
625 }
626 
628  // It is illegal to typedef parameterized types inside an interface. Therefore
629  // an Objective-C type can only be dependent on a type parameter when the type
630  // parameter structurally present in the type itself.
631  class IsObjCTypeParamDependentTypeVisitor
632  : public RecursiveASTVisitor<IsObjCTypeParamDependentTypeVisitor> {
633  public:
634  IsObjCTypeParamDependentTypeVisitor() : Result(false) {}
635  bool VisitObjCTypeParamType(const ObjCTypeParamType *Type) {
636  if (isa<ObjCTypeParamDecl>(Type->getDecl())) {
637  Result = true;
638  return false;
639  }
640  return true;
641  }
642 
643  bool Result;
644  };
645 
646  IsObjCTypeParamDependentTypeVisitor Visitor;
647  Visitor.TraverseType(Type);
648  return Visitor.Result;
649 }
650 
651 /// A method might not be available in the interface indicated by the static
652 /// type. However it might be available in the tracked type. In order to
653 /// properly substitute the type parameters we need the declaration context of
654 /// the method. The more specialized the enclosing class of the method is, the
655 /// more likely that the parameter substitution will be successful.
656 static const ObjCMethodDecl *
657 findMethodDecl(const ObjCMessageExpr *MessageExpr,
658  const ObjCObjectPointerType *TrackedType, ASTContext &ASTCtxt) {
659  const ObjCMethodDecl *Method = nullptr;
660 
661  QualType ReceiverType = MessageExpr->getReceiverType();
662  const auto *ReceiverObjectPtrType =
663  ReceiverType->getAs<ObjCObjectPointerType>();
664 
665  // Do this "devirtualization" on instance and class methods only. Trust the
666  // static type on super and super class calls.
667  if (MessageExpr->getReceiverKind() == ObjCMessageExpr::Instance ||
668  MessageExpr->getReceiverKind() == ObjCMessageExpr::Class) {
669  // When the receiver type is id, Class, or some super class of the tracked
670  // type, look up the method in the tracked type, not in the receiver type.
671  // This way we preserve more information.
672  if (ReceiverType->isObjCIdType() || ReceiverType->isObjCClassType() ||
673  ASTCtxt.canAssignObjCInterfaces(ReceiverObjectPtrType, TrackedType)) {
674  const ObjCInterfaceDecl *InterfaceDecl = TrackedType->getInterfaceDecl();
675  // The method might not be found.
676  Selector Sel = MessageExpr->getSelector();
677  Method = InterfaceDecl->lookupInstanceMethod(Sel);
678  if (!Method)
679  Method = InterfaceDecl->lookupClassMethod(Sel);
680  }
681  }
682 
683  // Fallback to statick method lookup when the one based on the tracked type
684  // failed.
685  return Method ? Method : MessageExpr->getMethodDecl();
686 }
687 
688 /// Get the returned ObjCObjectPointerType by a method based on the tracked type
689 /// information, or null pointer when the returned type is not an
690 /// ObjCObjectPointerType.
692  const ObjCMethodDecl *Method, ArrayRef<QualType> TypeArgs,
693  const ObjCObjectPointerType *SelfType, ASTContext &C) {
694  QualType StaticResultType = Method->getReturnType();
695 
696  // Is the return type declared as instance type?
697  if (StaticResultType == C.getObjCInstanceType())
698  return QualType(SelfType, 0);
699 
700  // Check whether the result type depends on a type parameter.
701  if (!isObjCTypeParamDependent(StaticResultType))
702  return QualType();
703 
704  QualType ResultType = StaticResultType.substObjCTypeArgs(
705  C, TypeArgs, ObjCSubstitutionContext::Result);
706 
707  return ResultType;
708 }
709 
710 /// When the receiver has a tracked type, use that type to validate the
711 /// argumments of the message expression and the return value.
712 void DynamicTypePropagation::checkPreObjCMessage(const ObjCMethodCall &M,
713  CheckerContext &C) const {
714  ProgramStateRef State = C.getState();
715  SymbolRef Sym = M.getReceiverSVal().getAsSymbol();
716  if (!Sym)
717  return;
718 
719  const ObjCObjectPointerType *const *TrackedType =
720  State->get<MostSpecializedTypeArgsMap>(Sym);
721  if (!TrackedType)
722  return;
723 
724  // Get the type arguments from tracked type and substitute type arguments
725  // before do the semantic check.
726 
727  ASTContext &ASTCtxt = C.getASTContext();
728  const ObjCMessageExpr *MessageExpr = M.getOriginExpr();
729  const ObjCMethodDecl *Method =
730  findMethodDecl(MessageExpr, *TrackedType, ASTCtxt);
731 
732  // It is possible to call non-existent methods in Obj-C.
733  if (!Method)
734  return;
735 
736  // If the method is declared on a class that has a non-invariant
737  // type parameter, don't warn about parameter mismatches after performing
738  // substitution. This prevents warning when the programmer has purposely
739  // casted the receiver to a super type or unspecialized type but the analyzer
740  // has a more precise tracked type than the programmer intends at the call
741  // site.
742  //
743  // For example, consider NSArray (which has a covariant type parameter)
744  // and NSMutableArray (a subclass of NSArray where the type parameter is
745  // invariant):
746  // NSMutableArray *a = [[NSMutableArray<NSString *> alloc] init;
747  //
748  // [a containsObject:number]; // Safe: -containsObject is defined on NSArray.
749  // NSArray<NSObject *> *other = [a arrayByAddingObject:number] // Safe
750  //
751  // [a addObject:number] // Unsafe: -addObject: is defined on NSMutableArray
752  //
753 
754  const ObjCInterfaceDecl *Interface = Method->getClassInterface();
755  if (!Interface)
756  return;
757 
758  ObjCTypeParamList *TypeParams = Interface->getTypeParamList();
759  if (!TypeParams)
760  return;
761 
762  for (ObjCTypeParamDecl *TypeParam : *TypeParams) {
763  if (TypeParam->getVariance() != ObjCTypeParamVariance::Invariant)
764  return;
765  }
766 
767  Optional<ArrayRef<QualType>> TypeArgs =
768  (*TrackedType)->getObjCSubstitutions(Method->getDeclContext());
769  // This case might happen when there is an unspecialized override of a
770  // specialized method.
771  if (!TypeArgs)
772  return;
773 
774  for (unsigned i = 0; i < Method->param_size(); i++) {
775  const Expr *Arg = MessageExpr->getArg(i);
776  const ParmVarDecl *Param = Method->parameters()[i];
777 
778  QualType OrigParamType = Param->getType();
779  if (!isObjCTypeParamDependent(OrigParamType))
780  continue;
781 
782  QualType ParamType = OrigParamType.substObjCTypeArgs(
783  ASTCtxt, *TypeArgs, ObjCSubstitutionContext::Parameter);
784  // Check if it can be assigned
785  const auto *ParamObjectPtrType = ParamType->getAs<ObjCObjectPointerType>();
786  const auto *ArgObjectPtrType =
788  if (!ParamObjectPtrType || !ArgObjectPtrType)
789  continue;
790 
791  // Check if we have more concrete tracked type that is not a super type of
792  // the static argument type.
793  SVal ArgSVal = M.getArgSVal(i);
794  SymbolRef ArgSym = ArgSVal.getAsSymbol();
795  if (ArgSym) {
796  const ObjCObjectPointerType *const *TrackedArgType =
797  State->get<MostSpecializedTypeArgsMap>(ArgSym);
798  if (TrackedArgType &&
799  ASTCtxt.canAssignObjCInterfaces(ArgObjectPtrType, *TrackedArgType)) {
800  ArgObjectPtrType = *TrackedArgType;
801  }
802  }
803 
804  // Warn when argument is incompatible with the parameter.
805  if (!ASTCtxt.canAssignObjCInterfaces(ParamObjectPtrType,
806  ArgObjectPtrType)) {
807  static CheckerProgramPointTag Tag(this, "ArgTypeMismatch");
808  ExplodedNode *N = C.addTransition(State, &Tag);
809  reportGenericsBug(ArgObjectPtrType, ParamObjectPtrType, N, Sym, C, Arg);
810  return;
811  }
812  }
813 }
814 
815 /// This callback is used to infer the types for Class variables. This info is
816 /// used later to validate messages that sent to classes. Class variables are
817 /// initialized with by invoking the 'class' method on a class.
818 /// This method is also used to infer the type information for the return
819 /// types.
820 // TODO: right now it only tracks generic types. Extend this to track every
821 // type in the DynamicTypeMap and diagnose type errors!
822 void DynamicTypePropagation::checkPostObjCMessage(const ObjCMethodCall &M,
823  CheckerContext &C) const {
824  const ObjCMessageExpr *MessageExpr = M.getOriginExpr();
825 
826  SymbolRef RetSym = M.getReturnValue().getAsSymbol();
827  if (!RetSym)
828  return;
829 
830  Selector Sel = MessageExpr->getSelector();
831  ProgramStateRef State = C.getState();
832  // Inference for class variables.
833  // We are only interested in cases where the class method is invoked on a
834  // class. This method is provided by the runtime and available on all classes.
835  if (MessageExpr->getReceiverKind() == ObjCMessageExpr::Class &&
836  Sel.getAsString() == "class") {
837  QualType ReceiverType = MessageExpr->getClassReceiver();
838  const auto *ReceiverClassType = ReceiverType->getAs<ObjCObjectType>();
839  QualType ReceiverClassPointerType =
840  C.getASTContext().getObjCObjectPointerType(
841  QualType(ReceiverClassType, 0));
842 
843  if (!ReceiverClassType->isSpecialized())
844  return;
845  const auto *InferredType =
846  ReceiverClassPointerType->getAs<ObjCObjectPointerType>();
847  assert(InferredType);
848 
849  State = State->set<MostSpecializedTypeArgsMap>(RetSym, InferredType);
850  C.addTransition(State);
851  return;
852  }
853 
854  // Tracking for return types.
855  SymbolRef RecSym = M.getReceiverSVal().getAsSymbol();
856  if (!RecSym)
857  return;
858 
859  const ObjCObjectPointerType *const *TrackedType =
860  State->get<MostSpecializedTypeArgsMap>(RecSym);
861  if (!TrackedType)
862  return;
863 
864  ASTContext &ASTCtxt = C.getASTContext();
865  const ObjCMethodDecl *Method =
866  findMethodDecl(MessageExpr, *TrackedType, ASTCtxt);
867  if (!Method)
868  return;
869 
870  Optional<ArrayRef<QualType>> TypeArgs =
871  (*TrackedType)->getObjCSubstitutions(Method->getDeclContext());
872  if (!TypeArgs)
873  return;
874 
875  QualType ResultType =
876  getReturnTypeForMethod(Method, *TypeArgs, *TrackedType, ASTCtxt);
877  // The static type is the same as the deduced type.
878  if (ResultType.isNull())
879  return;
880 
881  const MemRegion *RetRegion = M.getReturnValue().getAsRegion();
882  ExplodedNode *Pred = C.getPredecessor();
883  // When there is an entry available for the return symbol in DynamicTypeMap,
884  // the call was inlined, and the information in the DynamicTypeMap is should
885  // be precise.
886  if (RetRegion && !State->get<DynamicTypeMap>(RetRegion)) {
887  // TODO: we have duplicated information in DynamicTypeMap and
888  // MostSpecializedTypeArgsMap. We should only store anything in the later if
889  // the stored data differs from the one stored in the former.
890  State = setDynamicTypeInfo(State, RetRegion, ResultType,
891  /*CanBeSubclass=*/true);
892  Pred = C.addTransition(State);
893  }
894 
895  const auto *ResultPtrType = ResultType->getAs<ObjCObjectPointerType>();
896 
897  if (!ResultPtrType || ResultPtrType->isUnspecialized())
898  return;
899 
900  // When the result is a specialized type and it is not tracked yet, track it
901  // for the result symbol.
902  if (!State->get<MostSpecializedTypeArgsMap>(RetSym)) {
903  State = State->set<MostSpecializedTypeArgsMap>(RetSym, ResultPtrType);
904  C.addTransition(State, Pred);
905  }
906 }
907 
908 void DynamicTypePropagation::reportGenericsBug(
909  const ObjCObjectPointerType *From, const ObjCObjectPointerType *To,
910  ExplodedNode *N, SymbolRef Sym, CheckerContext &C,
911  const Stmt *ReportedNode) const {
912  if (!CheckGenerics)
913  return;
914 
915  initBugType();
916  SmallString<192> Buf;
917  llvm::raw_svector_ostream OS(Buf);
918  OS << "Conversion from value of type '";
919  QualType::print(From, Qualifiers(), OS, C.getLangOpts(), llvm::Twine());
920  OS << "' to incompatible type '";
921  QualType::print(To, Qualifiers(), OS, C.getLangOpts(), llvm::Twine());
922  OS << "'";
923  std::unique_ptr<BugReport> R(
924  new BugReport(*ObjCGenericsBugType, OS.str(), N));
925  R->markInteresting(Sym);
926  R->addVisitor(llvm::make_unique<GenericsBugVisitor>(Sym));
927  if (ReportedNode)
928  R->addRange(ReportedNode->getSourceRange());
929  C.emitReport(std::move(R));
930 }
931 
932 std::shared_ptr<PathDiagnosticPiece>
933 DynamicTypePropagation::GenericsBugVisitor::VisitNode(const ExplodedNode *N,
934  BugReporterContext &BRC,
935  BugReport &BR) {
936  ProgramStateRef state = N->getState();
937  ProgramStateRef statePrev = N->getFirstPred()->getState();
938 
939  const ObjCObjectPointerType *const *TrackedType =
940  state->get<MostSpecializedTypeArgsMap>(Sym);
941  const ObjCObjectPointerType *const *TrackedTypePrev =
942  statePrev->get<MostSpecializedTypeArgsMap>(Sym);
943  if (!TrackedType)
944  return nullptr;
945 
946  if (TrackedTypePrev && *TrackedTypePrev == *TrackedType)
947  return nullptr;
948 
949  // Retrieve the associated statement.
951  if (!S)
952  return nullptr;
953 
954  const LangOptions &LangOpts = BRC.getASTContext().getLangOpts();
955 
956  SmallString<256> Buf;
957  llvm::raw_svector_ostream OS(Buf);
958  OS << "Type '";
959  QualType::print(*TrackedType, Qualifiers(), OS, LangOpts, llvm::Twine());
960  OS << "' is inferred from ";
961 
962  if (const auto *ExplicitCast = dyn_cast<ExplicitCastExpr>(S)) {
963  OS << "explicit cast (from '";
964  QualType::print(ExplicitCast->getSubExpr()->getType().getTypePtr(),
965  Qualifiers(), OS, LangOpts, llvm::Twine());
966  OS << "' to '";
967  QualType::print(ExplicitCast->getType().getTypePtr(), Qualifiers(), OS,
968  LangOpts, llvm::Twine());
969  OS << "')";
970  } else if (const auto *ImplicitCast = dyn_cast<ImplicitCastExpr>(S)) {
971  OS << "implicit cast (from '";
972  QualType::print(ImplicitCast->getSubExpr()->getType().getTypePtr(),
973  Qualifiers(), OS, LangOpts, llvm::Twine());
974  OS << "' to '";
975  QualType::print(ImplicitCast->getType().getTypePtr(), Qualifiers(), OS,
976  LangOpts, llvm::Twine());
977  OS << "')";
978  } else {
979  OS << "this context";
980  }
981 
982  // Generate the extra diagnostic.
983  PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
984  N->getLocationContext());
985  return std::make_shared<PathDiagnosticEventPiece>(Pos, OS.str(), true,
986  nullptr);
987 }
988 
989 /// Register checkers.
990 void ento::registerObjCGenericsChecker(CheckerManager &mgr) {
991  DynamicTypePropagation *checker =
992  mgr.registerChecker<DynamicTypePropagation>();
993  checker->CheckGenerics = true;
994 }
995 
996 void ento::registerDynamicTypePropagation(CheckerManager &mgr) {
997  mgr.registerChecker<DynamicTypePropagation>();
998 }
SVal getReceiverSVal() const
Returns the value of the receiver at the time of this call.
Definition: CallEvent.cpp:960
const char *const CoreFoundationObjectiveC
The receiver is an object instance.
Definition: ExprObjC.h:1055
Smart pointer class that efficiently represents Objective-C method names.
A (possibly-)qualified type.
Definition: Type.h:638
QualType substObjCTypeArgs(ASTContext &ctx, ArrayRef< QualType > typeArgs, ObjCSubstitutionContext context) const
Substitute type arguments for the Objective-C type parameters used in the subject type...
Definition: Type.cpp:1139
unsigned param_size() const
Definition: DeclObjC.h:341
Selector getSelector() const
Definition: ExprObjC.cpp:312
ObjCInterfaceDecl * getClassInterface()
Definition: DeclObjC.cpp:1144
const SymExpr * SymbolRef
Stmt - This represents one statement.
Definition: Stmt.h:66
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:87
IntrusiveRefCntPtr< const ProgramState > ProgramStateRef
ObjCTypeParamList * getTypeParamList() const
Retrieve the type parameters of this class.
Definition: DeclObjC.cpp:308
The base class of the type hierarchy.
Definition: Type.h:1407
Stmt * getParent(Stmt *) const
Definition: ParentMap.cpp:123
bool isUnspecialized() const
Whether this type is unspecialized, meaning that is has no type arguments.
Definition: Type.h:5895
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6748
static void recordFixedType(const MemRegion *Region, const CXXMethodDecl *MD, CheckerContext &C)
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:139
Represents a parameter to a function.
Definition: Decl.h:1550
The collection of all-type qualifiers we support.
Definition: Type.h:141
static const ObjCMethodDecl * findMethodDecl(const ObjCMessageExpr *MessageExpr, const ObjCObjectPointerType *TrackedType, ASTContext &ASTCtxt)
A method might not be available in the interface indicated by the static type.
Represents a class type in Objective C.
Definition: Type.h:5538
ObjCMethodDecl * lookupInstanceMethod(Selector Sel) const
Lookup an instance method for a given selector.
Definition: DeclObjC.h:1847
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:155
LineState State
bool isObjCIdType() const
Definition: Type.h:6422
bool isSpecialized() const
Whether this type is specialized, meaning that it has type arguments.
Definition: Type.h:5887
Expr * getSubExpr()
Definition: Expr.h:3055
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:50
i32 captured_struct **param SharedsTy A type which contains references the shared variables *param Shareds Context with the list of shared variables from the p *TaskFunction *param Data Additional data for task generation like final * state
const ObjCObjectPointerType * stripObjCKindOfTypeAndQuals(const ASTContext &ctx) const
Strip off the Objective-C "kindof" type and (with it) any protocol qualifiers.
Definition: Type.cpp:717
static bool isObjCTypeParamDependent(QualType Type)
Represents any expression that calls an Objective-C method.
Definition: CallEvent.h:970
const ImplicitParamDecl * getSelfDecl() const
void print(raw_ostream &OS, const PrintingPolicy &Policy, const Twine &PlaceHolder=Twine(), unsigned Indentation=0) const
static QualType getReturnTypeForMethod(const ObjCMethodDecl *Method, ArrayRef< QualType > TypeArgs, const ObjCObjectPointerType *SelfType, ASTContext &C)
Get the returned ObjCObjectPointerType by a method based on the tracked type information, or null pointer when the returned type is not an ObjCObjectPointerType.
ObjCMethodDecl * lookupClassMethod(Selector Sel) const
Lookup a class method for a given selector.
Definition: DeclObjC.h:1852
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:3003
A class that does preorder or postorder depth-first traversal on the entire Clang AST and visits each...
Represents an ObjC class declaration.
Definition: DeclObjC.h:1172
QualType getReturnType() const
Definition: DeclObjC.h:323
llvm::ImmutableMap< const MemRegion *, DynamicTypeInfo > DynamicTypeMapImpl
ObjCTypeParamDecl * getDecl() const
Definition: Type.h:5507
This represents one expression.
Definition: Expr.h:106
static bool storeWhenMoreInformative(ProgramStateRef &State, SymbolRef Sym, const ObjCObjectPointerType *const *Current, const ObjCObjectPointerType *StaticLowerBound, const ObjCObjectPointerType *StaticUpperBound, ASTContext &C)
Inputs:
Represents an implicit call to a C++ destructor.
Definition: CallEvent.h:800
bool hasRelatedResultType() const
Determine whether this method has a result type that is related to the message receiver&#39;s type...
Definition: DeclObjC.h:257
bool isObjCClassType() const
Definition: Type.h:6428
DeclContext * getDeclContext()
Definition: DeclBase.h:427
bool isObjCIdType() const
True if this is equivalent to the &#39;id&#39; type, i.e.
Definition: Type.h:5856
QualType getType() const
Definition: Expr.h:128
ProgramStateRef setDynamicTypeInfo(ProgramStateRef State, const MemRegion *Reg, DynamicTypeInfo NewTy)
Set dynamic type information of the region; return the new state.
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:904
QualType getRecordType(const RecordDecl *Decl) const
ReceiverKind getReceiverKind() const
Determine the kind of receiver that this message is being sent to.
Definition: ExprObjC.h:1188
The result type of a method or function.
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:703
ParentMap & getParentMap() const
Expr * getArg(unsigned Arg)
getArg - Return the specified argument.
Definition: ExprObjC.h:1342
static const Stmt * getStmt(const ExplodedNode *N)
Given an exploded node, retrieve the statement that should be used for the diagnostic location...
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:945
std::string getAsString() const
Derive the full selector name (e.g.
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:5304
CastKind getCastKind() const
Definition: Expr.h:3049
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:1914
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:2041
bool isArray() const
Definition: ExprCXX.h:2038
QualType getReceiverType() const
Retrieve the receiver type to which this message is being directed.
Definition: ExprObjC.cpp:319
bool isSuperClassOf(const ObjCInterfaceDecl *I) const
isSuperClassOf - Return true if this class is the specified class or is a super class of the specifie...
Definition: DeclObjC.h:1810
QualType getSuperClassType() const
Retrieve the type of the superclass of this object type.
Definition: Type.h:5666
const ObjCMethodDecl * getMethodDecl() const
Definition: ExprObjC.h:1303
QualType getObjCInstanceType()
Retrieve the Objective-C "instancetype" type, if already known; otherwise, returns a NULL type;...
Definition: ASTContext.h:1730
Expr * getInstanceReceiver()
Returns the object expression (receiver) for an instance message, or null for a message that is not a...
Definition: ExprObjC.h:1207
static const ObjCObjectPointerType * getMostInformativeDerivedClassImpl(const ObjCObjectPointerType *From, const ObjCObjectPointerType *To, const ObjCObjectPointerType *MostInformativeCandidate, ASTContext &C)
virtual const ObjCMessageExpr * getOriginExpr() const
Definition: CallEvent.h:994
Dataflow Directional Tag Classes.
DynamicTypeInfo getDynamicTypeInfo(ProgramStateRef State, const MemRegion *Reg)
Get dynamic type information for a region.
QualType getSuperType() const
Retrieve the type referred to by &#39;super&#39;.
Definition: ExprObjC.h:1283
Represents the declaration of an Objective-C type parameter.
Definition: DeclObjC.h:559
const CXXRecordDecl * getParent() const
Returns the parent of this method declaration, which is the class in which this method is defined...
Definition: DeclCXX.h:2166
const ObjCObjectType * getObjectType() const
Gets the type pointed to by this ObjC pointer.
Definition: Type.h:5835
const Decl * getDecl() const
Expr * IgnoreParenImpCasts() LLVM_READONLY
IgnoreParenImpCasts - Ignore parentheses and implicit casts.
Definition: Expr.cpp:2693
QualType getClassReceiver() const
Returns the type of a class message send, or NULL if the message is not a class message.
Definition: ExprObjC.h:1226
Represents a pointer to an Objective C object.
Definition: Type.h:5794
REGISTER_MAP_WITH_PROGRAMSTATE(MostSpecializedTypeArgsMap, SymbolRef, const ObjCObjectPointerType *) namespace
Indicates that the tracking object is a descendant of a referenced-counted OSObject, used in the Darwin kernel.
ObjCInterfaceDecl * getInterfaceDecl() const
If this pointer points to an Objective @interface type, gets the declaration for that interface...
Definition: Type.h:5850
const StackFrameContext * getStackFrame() const
ObjCInterfaceDecl * getCanonicalDecl() override
Retrieves the canonical declaration of this Objective-C class.
Definition: DeclObjC.h:1915
bool canAssignObjCInterfaces(const ObjCObjectPointerType *LHSOPT, const ObjCObjectPointerType *RHSOPT)
canAssignObjCInterfaces - Return true if the two interface types are compatible for assignment from R...
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13954
Represents a type parameter type in Objective C.
Definition: Type.h:5464
static const ObjCObjectPointerType * getMostInformativeDerivedClass(const ObjCObjectPointerType *From, const ObjCObjectPointerType *To, ASTContext &C)
A downcast may loose specialization information.
The parameter type of a method or function.
static const Expr * stripCastsAndSugar(const Expr *E)
Stores a list of Objective-C type parameters for a parameterized class or a category/extension thereo...
Definition: DeclObjC.h:637
QualType getPointerType(QualType T) const
Return the uniqued reference to the type for a pointer to the specified type.
The receiver is a class.
Definition: ExprObjC.h:1052
SourceRange getSourceRange() const LLVM_READONLY
SourceLocation tokens are not useful in isolation - they are low level value objects created/interpre...
Definition: Stmt.cpp:276
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1041
QualType getType() const
Definition: Decl.h:648
QualType getObjCObjectPointerType(QualType OIT) const
Return a ObjCObjectPointerType type for the given ObjCObjectType.
The receiver is a superclass.
Definition: ExprObjC.h:1058
Represents a call to a C++ constructor.
Definition: CallEvent.h:849
The parameter is invariant: must match exactly.
Defines enum values for all the target-independent builtin functions.
ArrayRef< ParmVarDecl * > parameters() const
Definition: DeclObjC.h:367