CallEvent.cpp revision f8ddc098981d4d85cad4e72fc6dfcfe83b842b66 
1//===- Calls.cpp - Wrapper for all function and method calls ------*- 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/// \file This file defines CallEvent and its subclasses, which represent path-
11/// sensitive instances of different kinds of function and method calls
12/// (C, C++, and Objective-C).
13//
14//===----------------------------------------------------------------------===//
15
16#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
17#include "clang/AST/ParentMap.h"
18#include "clang/Analysis/ProgramPoint.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
20#include "llvm/ADT/SmallSet.h"
21#include "llvm/ADT/StringExtras.h"
22#include "llvm/Support/raw_ostream.h"
23
24using namespace clang;
25using namespace ento;
26
27QualType CallEvent::getResultType() const {
28  const Expr *E = getOriginExpr();
29  assert(E && "Calls without origin expressions do not have results");
30  QualType ResultTy = E->getType();
31
32  ASTContext &Ctx = getState()->getStateManager().getContext();
33
34  // A function that returns a reference to 'int' will have a result type
35  // of simply 'int'. Check the origin expr's value kind to recover the
36  // proper type.
37  switch (E->getValueKind()) {
38  case VK_LValue:
39    ResultTy = Ctx.getLValueReferenceType(ResultTy);
40    break;
41  case VK_XValue:
42    ResultTy = Ctx.getRValueReferenceType(ResultTy);
43    break;
44  case VK_RValue:
45    // No adjustment is necessary.
46    break;
47  }
48
49  return ResultTy;
50}
51
52static bool isCallbackArg(SVal V, QualType T) {
53  // If the parameter is 0, it's harmless.
54  if (V.isZeroConstant())
55    return false;
56
57  // If a parameter is a block or a callback, assume it can modify pointer.
58  if (T->isBlockPointerType() ||
59      T->isFunctionPointerType() ||
60      T->isObjCSelType())
61    return true;
62
63  // Check if a callback is passed inside a struct (for both, struct passed by
64  // reference and by value). Dig just one level into the struct for now.
65
66  if (T->isAnyPointerType() || T->isReferenceType())
67    T = T->getPointeeType();
68
69  if (const RecordType *RT = T->getAsStructureType()) {
70    const RecordDecl *RD = RT->getDecl();
71    for (RecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
72         I != E; ++I) {
73      QualType FieldT = I->getType();
74      if (FieldT->isBlockPointerType() || FieldT->isFunctionPointerType())
75        return true;
76    }
77  }
78
79  return false;
80}
81
82bool CallEvent::hasNonZeroCallbackArg() const {
83  unsigned NumOfArgs = getNumArgs();
84
85  // If calling using a function pointer, assume the function does not
86  // have a callback. TODO: We could check the types of the arguments here.
87  if (!getDecl())
88    return false;
89
90  unsigned Idx = 0;
91  for (CallEvent::param_type_iterator I = param_type_begin(),
92                                       E = param_type_end();
93       I != E && Idx < NumOfArgs; ++I, ++Idx) {
94    if (NumOfArgs <= Idx)
95      break;
96
97    if (isCallbackArg(getArgSVal(Idx), *I))
98      return true;
99  }
100
101  return false;
102}
103
104bool CallEvent::isGlobalCFunction(StringRef FunctionName) const {
105  const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(getDecl());
106  if (!FD)
107    return false;
108
109  return CheckerContext::isCLibraryFunction(FD, FunctionName);
110}
111
112/// \brief Returns true if a type is a pointer-to-const or reference-to-const
113/// with no further indirection.
114static bool isPointerToConst(QualType Ty) {
115  QualType PointeeTy = Ty->getPointeeType();
116  if (PointeeTy == QualType())
117    return false;
118  if (!PointeeTy.isConstQualified())
119    return false;
120  if (PointeeTy->isAnyPointerType())
121    return false;
122  return true;
123}
124
125// Try to retrieve the function declaration and find the function parameter
126// types which are pointers/references to a non-pointer const.
127// We will not invalidate the corresponding argument regions.
128static void findPtrToConstParams(llvm::SmallSet<unsigned, 4> &PreserveArgs,
129                                 const CallEvent &Call) {
130  unsigned Idx = 0;
131  for (CallEvent::param_type_iterator I = Call.param_type_begin(),
132                                      E = Call.param_type_end();
133       I != E; ++I, ++Idx) {
134    if (isPointerToConst(*I))
135      PreserveArgs.insert(Idx);
136  }
137}
138
139ProgramStateRef CallEvent::invalidateRegions(unsigned BlockCount,
140                                             ProgramStateRef Orig) const {
141  ProgramStateRef Result = (Orig ? Orig : getState());
142
143  SmallVector<const MemRegion *, 8> ConstRegions;
144  SmallVector<const MemRegion *, 8> RegionsToInvalidate;
145  getExtraInvalidatedRegions(RegionsToInvalidate);
146
147  // Indexes of arguments whose values will be preserved by the call.
148  llvm::SmallSet<unsigned, 4> PreserveArgs;
149  if (!argumentsMayEscape())
150    findPtrToConstParams(PreserveArgs, *this);
151
152  for (unsigned Idx = 0, Count = getNumArgs(); Idx != Count; ++Idx) {
153    const MemRegion *R = getArgSVal(Idx).getAsRegion();
154    if (!R)
155      continue;
156
157    // Mark this region for invalidation.  We batch invalidate regions
158    // below for efficiency.
159    if (PreserveArgs.count(Idx))
160      ConstRegions.push_back(R);
161    else
162      RegionsToInvalidate.push_back(R);
163  }
164
165  // Invalidate designated regions using the batch invalidation API.
166  // NOTE: Even if RegionsToInvalidate is empty, we may still invalidate
167  //  global variables.
168  return Result->invalidateRegions(RegionsToInvalidate, getOriginExpr(),
169                                   BlockCount, getLocationContext(),
170                                   /*CausedByPointerEscape*/ true,
171                                   /*Symbols=*/0, this, ConstRegions);
172}
173
174ProgramPoint CallEvent::getProgramPoint(bool IsPreVisit,
175                                        const ProgramPointTag *Tag) const {
176  if (const Expr *E = getOriginExpr()) {
177    if (IsPreVisit)
178      return PreStmt(E, getLocationContext(), Tag);
179    return PostStmt(E, getLocationContext(), Tag);
180  }
181
182  const Decl *D = getDecl();
183  assert(D && "Cannot get a program point without a statement or decl");
184
185  SourceLocation Loc = getSourceRange().getBegin();
186  if (IsPreVisit)
187    return PreImplicitCall(D, Loc, getLocationContext(), Tag);
188  return PostImplicitCall(D, Loc, getLocationContext(), Tag);
189}
190
191SVal CallEvent::getArgSVal(unsigned Index) const {
192  const Expr *ArgE = getArgExpr(Index);
193  if (!ArgE)
194    return UnknownVal();
195  return getSVal(ArgE);
196}
197
198SourceRange CallEvent::getArgSourceRange(unsigned Index) const {
199  const Expr *ArgE = getArgExpr(Index);
200  if (!ArgE)
201    return SourceRange();
202  return ArgE->getSourceRange();
203}
204
205SVal CallEvent::getReturnValue() const {
206  const Expr *E = getOriginExpr();
207  if (!E)
208    return UndefinedVal();
209  return getSVal(E);
210}
211
212void CallEvent::dump() const {
213  dump(llvm::errs());
214}
215
216void CallEvent::dump(raw_ostream &Out) const {
217  ASTContext &Ctx = getState()->getStateManager().getContext();
218  if (const Expr *E = getOriginExpr()) {
219    E->printPretty(Out, 0, Ctx.getPrintingPolicy());
220    Out << "\n";
221    return;
222  }
223
224  if (const Decl *D = getDecl()) {
225    Out << "Call to ";
226    D->print(Out, Ctx.getPrintingPolicy());
227    return;
228  }
229
230  // FIXME: a string representation of the kind would be nice.
231  Out << "Unknown call (type " << getKind() << ")";
232}
233
234
235bool CallEvent::isCallStmt(const Stmt *S) {
236  return isa<CallExpr>(S) || isa<ObjCMessageExpr>(S)
237                          || isa<CXXConstructExpr>(S)
238                          || isa<CXXNewExpr>(S);
239}
240
241QualType CallEvent::getDeclaredResultType(const Decl *D) {
242  assert(D);
243  if (const FunctionDecl* FD = dyn_cast<FunctionDecl>(D))
244    return FD->getResultType();
245  else if (const ObjCMethodDecl* MD = dyn_cast<ObjCMethodDecl>(D))
246    return MD->getResultType();
247  return QualType();
248}
249
250static void addParameterValuesToBindings(const StackFrameContext *CalleeCtx,
251                                         CallEvent::BindingsTy &Bindings,
252                                         SValBuilder &SVB,
253                                         const CallEvent &Call,
254                                         CallEvent::param_iterator I,
255                                         CallEvent::param_iterator E) {
256  MemRegionManager &MRMgr = SVB.getRegionManager();
257
258  unsigned Idx = 0;
259  for (; I != E; ++I, ++Idx) {
260    const ParmVarDecl *ParamDecl = *I;
261    assert(ParamDecl && "Formal parameter has no decl?");
262
263    SVal ArgVal = Call.getArgSVal(Idx);
264    if (!ArgVal.isUnknown()) {
265      Loc ParamLoc = SVB.makeLoc(MRMgr.getVarRegion(ParamDecl, CalleeCtx));
266      Bindings.push_back(std::make_pair(ParamLoc, ArgVal));
267    }
268  }
269
270  // FIXME: Variadic arguments are not handled at all right now.
271}
272
273
274CallEvent::param_iterator AnyFunctionCall::param_begin() const {
275  const FunctionDecl *D = getDecl();
276  if (!D)
277    return 0;
278
279  return D->param_begin();
280}
281
282CallEvent::param_iterator AnyFunctionCall::param_end() const {
283  const FunctionDecl *D = getDecl();
284  if (!D)
285    return 0;
286
287  return D->param_end();
288}
289
290void AnyFunctionCall::getInitialStackFrameContents(
291                                        const StackFrameContext *CalleeCtx,
292                                        BindingsTy &Bindings) const {
293  const FunctionDecl *D = cast<FunctionDecl>(CalleeCtx->getDecl());
294  SValBuilder &SVB = getState()->getStateManager().getSValBuilder();
295  addParameterValuesToBindings(CalleeCtx, Bindings, SVB, *this,
296                               D->param_begin(), D->param_end());
297}
298
299bool AnyFunctionCall::argumentsMayEscape() const {
300  if (hasNonZeroCallbackArg())
301    return true;
302
303  const FunctionDecl *D = getDecl();
304  if (!D)
305    return true;
306
307  const IdentifierInfo *II = D->getIdentifier();
308  if (!II)
309    return false;
310
311  // This set of "escaping" APIs is
312
313  // - 'int pthread_setspecific(ptheread_key k, const void *)' stores a
314  //   value into thread local storage. The value can later be retrieved with
315  //   'void *ptheread_getspecific(pthread_key)'. So even thought the
316  //   parameter is 'const void *', the region escapes through the call.
317  if (II->isStr("pthread_setspecific"))
318    return true;
319
320  // - xpc_connection_set_context stores a value which can be retrieved later
321  //   with xpc_connection_get_context.
322  if (II->isStr("xpc_connection_set_context"))
323    return true;
324
325  // - funopen - sets a buffer for future IO calls.
326  if (II->isStr("funopen"))
327    return true;
328
329  StringRef FName = II->getName();
330
331  // - CoreFoundation functions that end with "NoCopy" can free a passed-in
332  //   buffer even if it is const.
333  if (FName.endswith("NoCopy"))
334    return true;
335
336  // - NSXXInsertXX, for example NSMapInsertIfAbsent, since they can
337  //   be deallocated by NSMapRemove.
338  if (FName.startswith("NS") && (FName.find("Insert") != StringRef::npos))
339    return true;
340
341  // - Many CF containers allow objects to escape through custom
342  //   allocators/deallocators upon container construction. (PR12101)
343  if (FName.startswith("CF") || FName.startswith("CG")) {
344    return StrInStrNoCase(FName, "InsertValue")  != StringRef::npos ||
345           StrInStrNoCase(FName, "AddValue")     != StringRef::npos ||
346           StrInStrNoCase(FName, "SetValue")     != StringRef::npos ||
347           StrInStrNoCase(FName, "WithData")     != StringRef::npos ||
348           StrInStrNoCase(FName, "AppendValue")  != StringRef::npos ||
349           StrInStrNoCase(FName, "SetAttribute") != StringRef::npos;
350  }
351
352  return false;
353}
354
355
356const FunctionDecl *SimpleCall::getDecl() const {
357  const FunctionDecl *D = getOriginExpr()->getDirectCallee();
358  if (D)
359    return D;
360
361  return getSVal(getOriginExpr()->getCallee()).getAsFunctionDecl();
362}
363
364
365const FunctionDecl *CXXInstanceCall::getDecl() const {
366  const CallExpr *CE = cast_or_null<CallExpr>(getOriginExpr());
367  if (!CE)
368    return AnyFunctionCall::getDecl();
369
370  const FunctionDecl *D = CE->getDirectCallee();
371  if (D)
372    return D;
373
374  return getSVal(CE->getCallee()).getAsFunctionDecl();
375}
376
377void CXXInstanceCall::getExtraInvalidatedRegions(RegionList &Regions) const {
378  if (const MemRegion *R = getCXXThisVal().getAsRegion())
379    Regions.push_back(R);
380}
381
382SVal CXXInstanceCall::getCXXThisVal() const {
383  const Expr *Base = getCXXThisExpr();
384  // FIXME: This doesn't handle an overloaded ->* operator.
385  if (!Base)
386    return UnknownVal();
387
388  SVal ThisVal = getSVal(Base);
389  assert(ThisVal.isUnknownOrUndef() || ThisVal.getAs<Loc>());
390  return ThisVal;
391}
392
393
394RuntimeDefinition CXXInstanceCall::getRuntimeDefinition() const {
395  // Do we have a decl at all?
396  const Decl *D = getDecl();
397  if (!D)
398    return RuntimeDefinition();
399
400  // If the method is non-virtual, we know we can inline it.
401  const CXXMethodDecl *MD = cast<CXXMethodDecl>(D);
402  if (!MD->isVirtual())
403    return AnyFunctionCall::getRuntimeDefinition();
404
405  // Do we know the implicit 'this' object being called?
406  const MemRegion *R = getCXXThisVal().getAsRegion();
407  if (!R)
408    return RuntimeDefinition();
409
410  // Do we know anything about the type of 'this'?
411  DynamicTypeInfo DynType = getState()->getDynamicTypeInfo(R);
412  if (!DynType.isValid())
413    return RuntimeDefinition();
414
415  // Is the type a C++ class? (This is mostly a defensive check.)
416  QualType RegionType = DynType.getType()->getPointeeType();
417  assert(!RegionType.isNull() && "DynamicTypeInfo should always be a pointer.");
418
419  const CXXRecordDecl *RD = RegionType->getAsCXXRecordDecl();
420  if (!RD || !RD->hasDefinition())
421    return RuntimeDefinition();
422
423  // Find the decl for this method in that class.
424  const CXXMethodDecl *Result = MD->getCorrespondingMethodInClass(RD, true);
425  if (!Result) {
426    // We might not even get the original statically-resolved method due to
427    // some particularly nasty casting (e.g. casts to sister classes).
428    // However, we should at least be able to search up and down our own class
429    // hierarchy, and some real bugs have been caught by checking this.
430    assert(!RD->isDerivedFrom(MD->getParent()) && "Couldn't find known method");
431
432    // FIXME: This is checking that our DynamicTypeInfo is at least as good as
433    // the static type. However, because we currently don't update
434    // DynamicTypeInfo when an object is cast, we can't actually be sure the
435    // DynamicTypeInfo is up to date. This assert should be re-enabled once
436    // this is fixed. <rdar://problem/12287087>
437    //assert(!MD->getParent()->isDerivedFrom(RD) && "Bad DynamicTypeInfo");
438
439    return RuntimeDefinition();
440  }
441
442  // Does the decl that we found have an implementation?
443  const FunctionDecl *Definition;
444  if (!Result->hasBody(Definition))
445    return RuntimeDefinition();
446
447  // We found a definition. If we're not sure that this devirtualization is
448  // actually what will happen at runtime, make sure to provide the region so
449  // that ExprEngine can decide what to do with it.
450  if (DynType.canBeASubClass())
451    return RuntimeDefinition(Definition, R->StripCasts());
452  return RuntimeDefinition(Definition, /*DispatchRegion=*/0);
453}
454
455void CXXInstanceCall::getInitialStackFrameContents(
456                                            const StackFrameContext *CalleeCtx,
457                                            BindingsTy &Bindings) const {
458  AnyFunctionCall::getInitialStackFrameContents(CalleeCtx, Bindings);
459
460  // Handle the binding of 'this' in the new stack frame.
461  SVal ThisVal = getCXXThisVal();
462  if (!ThisVal.isUnknown()) {
463    ProgramStateManager &StateMgr = getState()->getStateManager();
464    SValBuilder &SVB = StateMgr.getSValBuilder();
465
466    const CXXMethodDecl *MD = cast<CXXMethodDecl>(CalleeCtx->getDecl());
467    Loc ThisLoc = SVB.getCXXThis(MD, CalleeCtx);
468
469    // If we devirtualized to a different member function, we need to make sure
470    // we have the proper layering of CXXBaseObjectRegions.
471    if (MD->getCanonicalDecl() != getDecl()->getCanonicalDecl()) {
472      ASTContext &Ctx = SVB.getContext();
473      const CXXRecordDecl *Class = MD->getParent();
474      QualType Ty = Ctx.getPointerType(Ctx.getRecordType(Class));
475
476      // FIXME: CallEvent maybe shouldn't be directly accessing StoreManager.
477      bool Failed;
478      ThisVal = StateMgr.getStoreManager().evalDynamicCast(ThisVal, Ty, Failed);
479      assert(!Failed && "Calling an incorrectly devirtualized method");
480    }
481
482    if (!ThisVal.isUnknown())
483      Bindings.push_back(std::make_pair(ThisLoc, ThisVal));
484  }
485}
486
487
488
489const Expr *CXXMemberCall::getCXXThisExpr() const {
490  return getOriginExpr()->getImplicitObjectArgument();
491}
492
493RuntimeDefinition CXXMemberCall::getRuntimeDefinition() const {
494  // C++11 [expr.call]p1: ...If the selected function is non-virtual, or if the
495  // id-expression in the class member access expression is a qualified-id,
496  // that function is called. Otherwise, its final overrider in the dynamic type
497  // of the object expression is called.
498  if (const MemberExpr *ME = dyn_cast<MemberExpr>(getOriginExpr()->getCallee()))
499    if (ME->hasQualifier())
500      return AnyFunctionCall::getRuntimeDefinition();
501
502  return CXXInstanceCall::getRuntimeDefinition();
503}
504
505
506const Expr *CXXMemberOperatorCall::getCXXThisExpr() const {
507  return getOriginExpr()->getArg(0);
508}
509
510
511const BlockDataRegion *BlockCall::getBlockRegion() const {
512  const Expr *Callee = getOriginExpr()->getCallee();
513  const MemRegion *DataReg = getSVal(Callee).getAsRegion();
514
515  return dyn_cast_or_null<BlockDataRegion>(DataReg);
516}
517
518CallEvent::param_iterator BlockCall::param_begin() const {
519  const BlockDecl *D = getBlockDecl();
520  if (!D)
521    return 0;
522  return D->param_begin();
523}
524
525CallEvent::param_iterator BlockCall::param_end() const {
526  const BlockDecl *D = getBlockDecl();
527  if (!D)
528    return 0;
529  return D->param_end();
530}
531
532void BlockCall::getExtraInvalidatedRegions(RegionList &Regions) const {
533  // FIXME: This also needs to invalidate captured globals.
534  if (const MemRegion *R = getBlockRegion())
535    Regions.push_back(R);
536}
537
538void BlockCall::getInitialStackFrameContents(const StackFrameContext *CalleeCtx,
539                                             BindingsTy &Bindings) const {
540  const BlockDecl *D = cast<BlockDecl>(CalleeCtx->getDecl());
541  SValBuilder &SVB = getState()->getStateManager().getSValBuilder();
542  addParameterValuesToBindings(CalleeCtx, Bindings, SVB, *this,
543                               D->param_begin(), D->param_end());
544}
545
546
547SVal CXXConstructorCall::getCXXThisVal() const {
548  if (Data)
549    return loc::MemRegionVal(static_cast<const MemRegion *>(Data));
550  return UnknownVal();
551}
552
553void CXXConstructorCall::getExtraInvalidatedRegions(RegionList &Regions) const {
554  if (Data)
555    Regions.push_back(static_cast<const MemRegion *>(Data));
556}
557
558void CXXConstructorCall::getInitialStackFrameContents(
559                                             const StackFrameContext *CalleeCtx,
560                                             BindingsTy &Bindings) const {
561  AnyFunctionCall::getInitialStackFrameContents(CalleeCtx, Bindings);
562
563  SVal ThisVal = getCXXThisVal();
564  if (!ThisVal.isUnknown()) {
565    SValBuilder &SVB = getState()->getStateManager().getSValBuilder();
566    const CXXMethodDecl *MD = cast<CXXMethodDecl>(CalleeCtx->getDecl());
567    Loc ThisLoc = SVB.getCXXThis(MD, CalleeCtx);
568    Bindings.push_back(std::make_pair(ThisLoc, ThisVal));
569  }
570}
571
572
573
574SVal CXXDestructorCall::getCXXThisVal() const {
575  if (Data)
576    return loc::MemRegionVal(DtorDataTy::getFromOpaqueValue(Data).getPointer());
577  return UnknownVal();
578}
579
580RuntimeDefinition CXXDestructorCall::getRuntimeDefinition() const {
581  // Base destructors are always called non-virtually.
582  // Skip CXXInstanceCall's devirtualization logic in this case.
583  if (isBaseDestructor())
584    return AnyFunctionCall::getRuntimeDefinition();
585
586  return CXXInstanceCall::getRuntimeDefinition();
587}
588
589
590CallEvent::param_iterator ObjCMethodCall::param_begin() const {
591  const ObjCMethodDecl *D = getDecl();
592  if (!D)
593    return 0;
594
595  return D->param_begin();
596}
597
598CallEvent::param_iterator ObjCMethodCall::param_end() const {
599  const ObjCMethodDecl *D = getDecl();
600  if (!D)
601    return 0;
602
603  return D->param_end();
604}
605
606void
607ObjCMethodCall::getExtraInvalidatedRegions(RegionList &Regions) const {
608  if (const MemRegion *R = getReceiverSVal().getAsRegion())
609    Regions.push_back(R);
610}
611
612SVal ObjCMethodCall::getSelfSVal() const {
613  const LocationContext *LCtx = getLocationContext();
614  const ImplicitParamDecl *SelfDecl = LCtx->getSelfDecl();
615  if (!SelfDecl)
616    return SVal();
617  return getState()->getSVal(getState()->getRegion(SelfDecl, LCtx));
618}
619
620SVal ObjCMethodCall::getReceiverSVal() const {
621  // FIXME: Is this the best way to handle class receivers?
622  if (!isInstanceMessage())
623    return UnknownVal();
624
625  if (const Expr *RecE = getOriginExpr()->getInstanceReceiver())
626    return getSVal(RecE);
627
628  // An instance message with no expression means we are sending to super.
629  // In this case the object reference is the same as 'self'.
630  assert(getOriginExpr()->getReceiverKind() == ObjCMessageExpr::SuperInstance);
631  SVal SelfVal = getSelfSVal();
632  assert(SelfVal.isValid() && "Calling super but not in ObjC method");
633  return SelfVal;
634}
635
636bool ObjCMethodCall::isReceiverSelfOrSuper() const {
637  if (getOriginExpr()->getReceiverKind() == ObjCMessageExpr::SuperInstance ||
638      getOriginExpr()->getReceiverKind() == ObjCMessageExpr::SuperClass)
639      return true;
640
641  if (!isInstanceMessage())
642    return false;
643
644  SVal RecVal = getSVal(getOriginExpr()->getInstanceReceiver());
645
646  return (RecVal == getSelfSVal());
647}
648
649SourceRange ObjCMethodCall::getSourceRange() const {
650  switch (getMessageKind()) {
651  case OCM_Message:
652    return getOriginExpr()->getSourceRange();
653  case OCM_PropertyAccess:
654  case OCM_Subscript:
655    return getContainingPseudoObjectExpr()->getSourceRange();
656  }
657  llvm_unreachable("unknown message kind");
658}
659
660typedef llvm::PointerIntPair<const PseudoObjectExpr *, 2> ObjCMessageDataTy;
661
662const PseudoObjectExpr *ObjCMethodCall::getContainingPseudoObjectExpr() const {
663  assert(Data != 0 && "Lazy lookup not yet performed.");
664  assert(getMessageKind() != OCM_Message && "Explicit message send.");
665  return ObjCMessageDataTy::getFromOpaqueValue(Data).getPointer();
666}
667
668ObjCMessageKind ObjCMethodCall::getMessageKind() const {
669  if (Data == 0) {
670    ParentMap &PM = getLocationContext()->getParentMap();
671    const Stmt *S = PM.getParent(getOriginExpr());
672    if (const PseudoObjectExpr *POE = dyn_cast_or_null<PseudoObjectExpr>(S)) {
673      const Expr *Syntactic = POE->getSyntacticForm();
674
675      // This handles the funny case of assigning to the result of a getter.
676      // This can happen if the getter returns a non-const reference.
677      if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(Syntactic))
678        Syntactic = BO->getLHS();
679
680      ObjCMessageKind K;
681      switch (Syntactic->getStmtClass()) {
682      case Stmt::ObjCPropertyRefExprClass:
683        K = OCM_PropertyAccess;
684        break;
685      case Stmt::ObjCSubscriptRefExprClass:
686        K = OCM_Subscript;
687        break;
688      default:
689        // FIXME: Can this ever happen?
690        K = OCM_Message;
691        break;
692      }
693
694      if (K != OCM_Message) {
695        const_cast<ObjCMethodCall *>(this)->Data
696          = ObjCMessageDataTy(POE, K).getOpaqueValue();
697        assert(getMessageKind() == K);
698        return K;
699      }
700    }
701
702    const_cast<ObjCMethodCall *>(this)->Data
703      = ObjCMessageDataTy(0, 1).getOpaqueValue();
704    assert(getMessageKind() == OCM_Message);
705    return OCM_Message;
706  }
707
708  ObjCMessageDataTy Info = ObjCMessageDataTy::getFromOpaqueValue(Data);
709  if (!Info.getPointer())
710    return OCM_Message;
711  return static_cast<ObjCMessageKind>(Info.getInt());
712}
713
714
715bool ObjCMethodCall::canBeOverridenInSubclass(ObjCInterfaceDecl *IDecl,
716                                             Selector Sel) const {
717  assert(IDecl);
718  const SourceManager &SM =
719    getState()->getStateManager().getContext().getSourceManager();
720
721  // If the class interface is declared inside the main file, assume it is not
722  // subcassed.
723  // TODO: It could actually be subclassed if the subclass is private as well.
724  // This is probably very rare.
725  SourceLocation InterfLoc = IDecl->getEndOfDefinitionLoc();
726  if (InterfLoc.isValid() && SM.isFromMainFile(InterfLoc))
727    return false;
728
729  // Assume that property accessors are not overridden.
730  if (getMessageKind() == OCM_PropertyAccess)
731    return false;
732
733  // We assume that if the method is public (declared outside of main file) or
734  // has a parent which publicly declares the method, the method could be
735  // overridden in a subclass.
736
737  // Find the first declaration in the class hierarchy that declares
738  // the selector.
739  ObjCMethodDecl *D = 0;
740  while (true) {
741    D = IDecl->lookupMethod(Sel, true);
742
743    // Cannot find a public definition.
744    if (!D)
745      return false;
746
747    // If outside the main file,
748    if (D->getLocation().isValid() && !SM.isFromMainFile(D->getLocation()))
749      return true;
750
751    if (D->isOverriding()) {
752      // Search in the superclass on the next iteration.
753      IDecl = D->getClassInterface();
754      if (!IDecl)
755        return false;
756
757      IDecl = IDecl->getSuperClass();
758      if (!IDecl)
759        return false;
760
761      continue;
762    }
763
764    return false;
765  };
766
767  llvm_unreachable("The while loop should always terminate.");
768}
769
770RuntimeDefinition ObjCMethodCall::getRuntimeDefinition() const {
771  const ObjCMessageExpr *E = getOriginExpr();
772  assert(E);
773  Selector Sel = E->getSelector();
774
775  if (E->isInstanceMessage()) {
776
777    // Find the the receiver type.
778    const ObjCObjectPointerType *ReceiverT = 0;
779    bool CanBeSubClassed = false;
780    QualType SupersType = E->getSuperType();
781    const MemRegion *Receiver = 0;
782
783    if (!SupersType.isNull()) {
784      // Super always means the type of immediate predecessor to the method
785      // where the call occurs.
786      ReceiverT = cast<ObjCObjectPointerType>(SupersType);
787    } else {
788      Receiver = getReceiverSVal().getAsRegion();
789      if (!Receiver)
790        return RuntimeDefinition();
791
792      DynamicTypeInfo DTI = getState()->getDynamicTypeInfo(Receiver);
793      QualType DynType = DTI.getType();
794      CanBeSubClassed = DTI.canBeASubClass();
795      ReceiverT = dyn_cast<ObjCObjectPointerType>(DynType);
796
797      if (ReceiverT && CanBeSubClassed)
798        if (ObjCInterfaceDecl *IDecl = ReceiverT->getInterfaceDecl())
799          if (!canBeOverridenInSubclass(IDecl, Sel))
800            CanBeSubClassed = false;
801    }
802
803    // Lookup the method implementation.
804    if (ReceiverT)
805      if (ObjCInterfaceDecl *IDecl = ReceiverT->getInterfaceDecl()) {
806        // Repeatedly calling lookupPrivateMethod() is expensive, especially
807        // when in many cases it returns null.  We cache the results so
808        // that repeated queries on the same ObjCIntefaceDecl and Selector
809        // don't incur the same cost.  On some test cases, we can see the
810        // same query being issued thousands of times.
811        //
812        // NOTE: This cache is essentially a "global" variable, but it
813        // only gets lazily created when we get here.  The value of the
814        // cache probably comes from it being global across ExprEngines,
815        // where the same queries may get issued.  If we are worried about
816        // concurrency, or possibly loading/unloading ASTs, etc., we may
817        // need to revisit this someday.  In terms of memory, this table
818        // stays around until clang quits, which also may be bad if we
819        // need to release memory.
820        typedef std::pair<const ObjCInterfaceDecl*, Selector>
821                PrivateMethodKey;
822        typedef llvm::DenseMap<PrivateMethodKey,
823                               Optional<const ObjCMethodDecl *> >
824                PrivateMethodCache;
825
826        static PrivateMethodCache PMC;
827        Optional<const ObjCMethodDecl *> &Val = PMC[std::make_pair(IDecl, Sel)];
828
829        // Query lookupPrivateMethod() if the cache does not hit.
830        if (!Val.hasValue())
831          Val = IDecl->lookupPrivateMethod(Sel);
832
833        const ObjCMethodDecl *MD = Val.getValue();
834        if (CanBeSubClassed)
835          return RuntimeDefinition(MD, Receiver);
836        else
837          return RuntimeDefinition(MD, 0);
838      }
839
840  } else {
841    // This is a class method.
842    // If we have type info for the receiver class, we are calling via
843    // class name.
844    if (ObjCInterfaceDecl *IDecl = E->getReceiverInterface()) {
845      // Find/Return the method implementation.
846      return RuntimeDefinition(IDecl->lookupPrivateClassMethod(Sel));
847    }
848  }
849
850  return RuntimeDefinition();
851}
852
853void ObjCMethodCall::getInitialStackFrameContents(
854                                             const StackFrameContext *CalleeCtx,
855                                             BindingsTy &Bindings) const {
856  const ObjCMethodDecl *D = cast<ObjCMethodDecl>(CalleeCtx->getDecl());
857  SValBuilder &SVB = getState()->getStateManager().getSValBuilder();
858  addParameterValuesToBindings(CalleeCtx, Bindings, SVB, *this,
859                               D->param_begin(), D->param_end());
860
861  SVal SelfVal = getReceiverSVal();
862  if (!SelfVal.isUnknown()) {
863    const VarDecl *SelfD = CalleeCtx->getAnalysisDeclContext()->getSelfDecl();
864    MemRegionManager &MRMgr = SVB.getRegionManager();
865    Loc SelfLoc = SVB.makeLoc(MRMgr.getVarRegion(SelfD, CalleeCtx));
866    Bindings.push_back(std::make_pair(SelfLoc, SelfVal));
867  }
868}
869
870CallEventRef<>
871CallEventManager::getSimpleCall(const CallExpr *CE, ProgramStateRef State,
872                                const LocationContext *LCtx) {
873  if (const CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(CE))
874    return create<CXXMemberCall>(MCE, State, LCtx);
875
876  if (const CXXOperatorCallExpr *OpCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
877    const FunctionDecl *DirectCallee = OpCE->getDirectCallee();
878    if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(DirectCallee))
879      if (MD->isInstance())
880        return create<CXXMemberOperatorCall>(OpCE, State, LCtx);
881
882  } else if (CE->getCallee()->getType()->isBlockPointerType()) {
883    return create<BlockCall>(CE, State, LCtx);
884  }
885
886  // Otherwise, it's a normal function call, static member function call, or
887  // something we can't reason about.
888  return create<FunctionCall>(CE, State, LCtx);
889}
890
891
892CallEventRef<>
893CallEventManager::getCaller(const StackFrameContext *CalleeCtx,
894                            ProgramStateRef State) {
895  const LocationContext *ParentCtx = CalleeCtx->getParent();
896  const LocationContext *CallerCtx = ParentCtx->getCurrentStackFrame();
897  assert(CallerCtx && "This should not be used for top-level stack frames");
898
899  const Stmt *CallSite = CalleeCtx->getCallSite();
900
901  if (CallSite) {
902    if (const CallExpr *CE = dyn_cast<CallExpr>(CallSite))
903      return getSimpleCall(CE, State, CallerCtx);
904
905    switch (CallSite->getStmtClass()) {
906    case Stmt::CXXConstructExprClass:
907    case Stmt::CXXTemporaryObjectExprClass: {
908      SValBuilder &SVB = State->getStateManager().getSValBuilder();
909      const CXXMethodDecl *Ctor = cast<CXXMethodDecl>(CalleeCtx->getDecl());
910      Loc ThisPtr = SVB.getCXXThis(Ctor, CalleeCtx);
911      SVal ThisVal = State->getSVal(ThisPtr);
912
913      return getCXXConstructorCall(cast<CXXConstructExpr>(CallSite),
914                                   ThisVal.getAsRegion(), State, CallerCtx);
915    }
916    case Stmt::CXXNewExprClass:
917      return getCXXAllocatorCall(cast<CXXNewExpr>(CallSite), State, CallerCtx);
918    case Stmt::ObjCMessageExprClass:
919      return getObjCMethodCall(cast<ObjCMessageExpr>(CallSite),
920                               State, CallerCtx);
921    default:
922      llvm_unreachable("This is not an inlineable statement.");
923    }
924  }
925
926  // Fall back to the CFG. The only thing we haven't handled yet is
927  // destructors, though this could change in the future.
928  const CFGBlock *B = CalleeCtx->getCallSiteBlock();
929  CFGElement E = (*B)[CalleeCtx->getIndex()];
930  assert(E.getAs<CFGImplicitDtor>() &&
931         "All other CFG elements should have exprs");
932  assert(!E.getAs<CFGTemporaryDtor>() && "We don't handle temporaries yet");
933
934  SValBuilder &SVB = State->getStateManager().getSValBuilder();
935  const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CalleeCtx->getDecl());
936  Loc ThisPtr = SVB.getCXXThis(Dtor, CalleeCtx);
937  SVal ThisVal = State->getSVal(ThisPtr);
938
939  const Stmt *Trigger;
940  if (Optional<CFGAutomaticObjDtor> AutoDtor = E.getAs<CFGAutomaticObjDtor>())
941    Trigger = AutoDtor->getTriggerStmt();
942  else
943    Trigger = Dtor->getBody();
944
945  return getCXXDestructorCall(Dtor, Trigger, ThisVal.getAsRegion(),
946                              E.getAs<CFGBaseDtor>().hasValue(), State,
947                              CallerCtx);
948}
949