RegionStore.cpp revision 50b5a5c32e07301e4edcc01aca1f8a49a128c66c
1//== RegionStore.cpp - Field-sensitive store model --------------*- 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 defines a basic region store model. In this model, we do have field
11// sensitivity. But we assume nothing about the heap shape. So recursive data
12// structures are largely ignored. Basically we do 1-limiting analysis.
13// Parameter pointers are assumed with no aliasing. Pointee objects of
14// parameters are created lazily.
15//
16//===----------------------------------------------------------------------===//
17#include "clang/AST/CharUnits.h"
18#include "clang/AST/DeclCXX.h"
19#include "clang/AST/ExprCXX.h"
20#include "clang/Analysis/Analyses/LiveVariables.h"
21#include "clang/Analysis/AnalysisContext.h"
22#include "clang/Basic/TargetInfo.h"
23#include "clang/StaticAnalyzer/Core/PathSensitive/ObjCMessage.h"
24#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
25#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
26#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
27#include "llvm/ADT/ImmutableList.h"
28#include "llvm/ADT/ImmutableMap.h"
29#include "llvm/ADT/Optional.h"
30#include "llvm/Support/raw_ostream.h"
31
32using namespace clang;
33using namespace ento;
34using llvm::Optional;
35
36//===----------------------------------------------------------------------===//
37// Representation of binding keys.
38//===----------------------------------------------------------------------===//
39
40namespace {
41class BindingKey {
42public:
43  enum Kind { Direct = 0x0, Default = 0x1 };
44private:
45  llvm ::PointerIntPair<const MemRegion*, 1> P;
46  uint64_t Offset;
47
48  explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k)
49    : P(r, (unsigned) k), Offset(offset) {}
50public:
51
52  bool isDirect() const { return P.getInt() == Direct; }
53
54  const MemRegion *getRegion() const { return P.getPointer(); }
55  uint64_t getOffset() const { return Offset; }
56
57  void Profile(llvm::FoldingSetNodeID& ID) const {
58    ID.AddPointer(P.getOpaqueValue());
59    ID.AddInteger(Offset);
60  }
61
62  static BindingKey Make(const MemRegion *R, Kind k);
63
64  bool operator<(const BindingKey &X) const {
65    if (P.getOpaqueValue() < X.P.getOpaqueValue())
66      return true;
67    if (P.getOpaqueValue() > X.P.getOpaqueValue())
68      return false;
69    return Offset < X.Offset;
70  }
71
72  bool operator==(const BindingKey &X) const {
73    return P.getOpaqueValue() == X.P.getOpaqueValue() &&
74           Offset == X.Offset;
75  }
76
77  bool isValid() const {
78    return getRegion() != NULL;
79  }
80};
81} // end anonymous namespace
82
83BindingKey BindingKey::Make(const MemRegion *R, Kind k) {
84  const RegionOffset &RO = R->getAsOffset();
85  if (RO.getRegion())
86    return BindingKey(RO.getRegion(), RO.getOffset(), k);
87
88  return BindingKey(R, 0, k);
89}
90
91namespace llvm {
92  static inline
93  raw_ostream &operator<<(raw_ostream &os, BindingKey K) {
94    os << '(' << K.getRegion() << ',' << K.getOffset()
95       << ',' << (K.isDirect() ? "direct" : "default")
96       << ')';
97    return os;
98  }
99} // end llvm namespace
100
101//===----------------------------------------------------------------------===//
102// Actual Store type.
103//===----------------------------------------------------------------------===//
104
105typedef llvm::ImmutableMap<BindingKey, SVal> RegionBindings;
106
107//===----------------------------------------------------------------------===//
108// Fine-grained control of RegionStoreManager.
109//===----------------------------------------------------------------------===//
110
111namespace {
112struct minimal_features_tag {};
113struct maximal_features_tag {};
114
115class RegionStoreFeatures {
116  bool SupportsFields;
117public:
118  RegionStoreFeatures(minimal_features_tag) :
119    SupportsFields(false) {}
120
121  RegionStoreFeatures(maximal_features_tag) :
122    SupportsFields(true) {}
123
124  void enableFields(bool t) { SupportsFields = t; }
125
126  bool supportsFields() const { return SupportsFields; }
127};
128}
129
130//===----------------------------------------------------------------------===//
131// Main RegionStore logic.
132//===----------------------------------------------------------------------===//
133
134namespace {
135
136class RegionStoreSubRegionMap : public SubRegionMap {
137public:
138  typedef llvm::ImmutableSet<const MemRegion*> Set;
139  typedef llvm::DenseMap<const MemRegion*, Set> Map;
140private:
141  Set::Factory F;
142  Map M;
143public:
144  bool add(const MemRegion* Parent, const MemRegion* SubRegion) {
145    Map::iterator I = M.find(Parent);
146
147    if (I == M.end()) {
148      M.insert(std::make_pair(Parent, F.add(F.getEmptySet(), SubRegion)));
149      return true;
150    }
151
152    I->second = F.add(I->second, SubRegion);
153    return false;
154  }
155
156  void process(SmallVectorImpl<const SubRegion*> &WL, const SubRegion *R);
157
158  ~RegionStoreSubRegionMap() {}
159
160  const Set *getSubRegions(const MemRegion *Parent) const {
161    Map::const_iterator I = M.find(Parent);
162    return I == M.end() ? NULL : &I->second;
163  }
164
165  bool iterSubRegions(const MemRegion* Parent, Visitor& V) const {
166    Map::const_iterator I = M.find(Parent);
167
168    if (I == M.end())
169      return true;
170
171    Set S = I->second;
172    for (Set::iterator SI=S.begin(),SE=S.end(); SI != SE; ++SI) {
173      if (!V.Visit(Parent, *SI))
174        return false;
175    }
176
177    return true;
178  }
179};
180
181void
182RegionStoreSubRegionMap::process(SmallVectorImpl<const SubRegion*> &WL,
183                                 const SubRegion *R) {
184  const MemRegion *superR = R->getSuperRegion();
185  if (add(superR, R))
186    if (const SubRegion *sr = dyn_cast<SubRegion>(superR))
187      WL.push_back(sr);
188}
189
190class RegionStoreManager : public StoreManager {
191  const RegionStoreFeatures Features;
192  RegionBindings::Factory RBFactory;
193
194public:
195  RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f)
196    : StoreManager(mgr),
197      Features(f),
198      RBFactory(mgr.getAllocator()) {}
199
200  SubRegionMap *getSubRegionMap(Store store) {
201    return getRegionStoreSubRegionMap(store);
202  }
203
204  RegionStoreSubRegionMap *getRegionStoreSubRegionMap(Store store);
205
206  Optional<SVal> getDirectBinding(RegionBindings B, const MemRegion *R);
207  /// getDefaultBinding - Returns an SVal* representing an optional default
208  ///  binding associated with a region and its subregions.
209  Optional<SVal> getDefaultBinding(RegionBindings B, const MemRegion *R);
210
211  /// setImplicitDefaultValue - Set the default binding for the provided
212  ///  MemRegion to the value implicitly defined for compound literals when
213  ///  the value is not specified.
214  StoreRef setImplicitDefaultValue(Store store, const MemRegion *R, QualType T);
215
216  /// ArrayToPointer - Emulates the "decay" of an array to a pointer
217  ///  type.  'Array' represents the lvalue of the array being decayed
218  ///  to a pointer, and the returned SVal represents the decayed
219  ///  version of that lvalue (i.e., a pointer to the first element of
220  ///  the array).  This is called by ExprEngine when evaluating
221  ///  casts from arrays to pointers.
222  SVal ArrayToPointer(Loc Array);
223
224  /// For DerivedToBase casts, create a CXXBaseObjectRegion and return it.
225  virtual SVal evalDerivedToBase(SVal derived, QualType basePtrType);
226
227  /// \brief Evaluates C++ dynamic_cast cast.
228  /// The callback may result in the following 3 scenarios:
229  ///  - Successful cast (ex: derived is subclass of base).
230  ///  - Failed cast (ex: derived is definitely not a subclass of base).
231  ///  - We don't know (base is a symbolic region and we don't have
232  ///    enough info to determine if the cast will succeed at run time).
233  /// The function returns an SVal representing the derived class; it's
234  /// valid only if Failed flag is set to false.
235  virtual SVal evalDynamicCast(SVal base, QualType derivedPtrType,bool &Failed);
236
237  StoreRef getInitialStore(const LocationContext *InitLoc) {
238    return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this);
239  }
240
241  //===-------------------------------------------------------------------===//
242  // Binding values to regions.
243  //===-------------------------------------------------------------------===//
244  RegionBindings invalidateGlobalRegion(MemRegion::Kind K,
245                                        const Expr *Ex,
246                                        unsigned Count,
247                                        const LocationContext *LCtx,
248                                        RegionBindings B,
249                                        InvalidatedRegions *Invalidated);
250
251  StoreRef invalidateRegions(Store store, ArrayRef<const MemRegion *> Regions,
252                             const Expr *E, unsigned Count,
253                             const LocationContext *LCtx,
254                             InvalidatedSymbols &IS,
255                             const CallOrObjCMessage *Call,
256                             InvalidatedRegions *Invalidated);
257
258public:   // Made public for helper classes.
259
260  void RemoveSubRegionBindings(RegionBindings &B, const MemRegion *R,
261                               RegionStoreSubRegionMap &M);
262
263  RegionBindings addBinding(RegionBindings B, BindingKey K, SVal V);
264
265  RegionBindings addBinding(RegionBindings B, const MemRegion *R,
266                     BindingKey::Kind k, SVal V);
267
268  const SVal *lookup(RegionBindings B, BindingKey K);
269  const SVal *lookup(RegionBindings B, const MemRegion *R, BindingKey::Kind k);
270
271  RegionBindings removeBinding(RegionBindings B, BindingKey K);
272  RegionBindings removeBinding(RegionBindings B, const MemRegion *R,
273                        BindingKey::Kind k);
274
275  RegionBindings removeBinding(RegionBindings B, const MemRegion *R) {
276    return removeBinding(removeBinding(B, R, BindingKey::Direct), R,
277                        BindingKey::Default);
278  }
279
280public: // Part of public interface to class.
281
282  StoreRef Bind(Store store, Loc LV, SVal V);
283
284  // BindDefault is only used to initialize a region with a default value.
285  StoreRef BindDefault(Store store, const MemRegion *R, SVal V) {
286    RegionBindings B = GetRegionBindings(store);
287    assert(!lookup(B, R, BindingKey::Default));
288    assert(!lookup(B, R, BindingKey::Direct));
289    return StoreRef(addBinding(B, R, BindingKey::Default, V)
290                      .getRootWithoutRetain(), *this);
291  }
292
293  StoreRef BindCompoundLiteral(Store store, const CompoundLiteralExpr *CL,
294                               const LocationContext *LC, SVal V);
295
296  StoreRef BindDecl(Store store, const VarRegion *VR, SVal InitVal);
297
298  StoreRef BindDeclWithNoInit(Store store, const VarRegion *) {
299    return StoreRef(store, *this);
300  }
301
302  /// BindStruct - Bind a compound value to a structure.
303  StoreRef BindStruct(Store store, const TypedValueRegion* R, SVal V);
304
305  StoreRef BindArray(Store store, const TypedValueRegion* R, SVal V);
306
307  /// KillStruct - Set the entire struct to unknown.
308  StoreRef KillStruct(Store store, const TypedRegion* R, SVal DefaultVal);
309
310  StoreRef Remove(Store store, Loc LV);
311
312  void incrementReferenceCount(Store store) {
313    GetRegionBindings(store).manualRetain();
314  }
315
316  /// If the StoreManager supports it, decrement the reference count of
317  /// the specified Store object.  If the reference count hits 0, the memory
318  /// associated with the object is recycled.
319  void decrementReferenceCount(Store store) {
320    GetRegionBindings(store).manualRelease();
321  }
322
323  bool includedInBindings(Store store, const MemRegion *region) const;
324
325  /// \brief Return the value bound to specified location in a given state.
326  ///
327  /// The high level logic for this method is this:
328  /// getBinding (L)
329  ///   if L has binding
330  ///     return L's binding
331  ///   else if L is in killset
332  ///     return unknown
333  ///   else
334  ///     if L is on stack or heap
335  ///       return undefined
336  ///     else
337  ///       return symbolic
338  SVal getBinding(Store store, Loc L, QualType T = QualType());
339
340  SVal getBindingForElement(Store store, const ElementRegion *R);
341
342  SVal getBindingForField(Store store, const FieldRegion *R);
343
344  SVal getBindingForObjCIvar(Store store, const ObjCIvarRegion *R);
345
346  SVal getBindingForVar(Store store, const VarRegion *R);
347
348  SVal getBindingForLazySymbol(const TypedValueRegion *R);
349
350  SVal getBindingForFieldOrElementCommon(Store store, const TypedValueRegion *R,
351                                         QualType Ty, const MemRegion *superR);
352
353  SVal getLazyBinding(const MemRegion *lazyBindingRegion,
354                      Store lazyBindingStore);
355
356  /// Get bindings for the values in a struct and return a CompoundVal, used
357  /// when doing struct copy:
358  /// struct s x, y;
359  /// x = y;
360  /// y's value is retrieved by this method.
361  SVal getBindingForStruct(Store store, const TypedValueRegion* R);
362
363  SVal getBindingForArray(Store store, const TypedValueRegion* R);
364
365  /// Used to lazily generate derived symbols for bindings that are defined
366  ///  implicitly by default bindings in a super region.
367  Optional<SVal> getBindingForDerivedDefaultValue(RegionBindings B,
368                                                  const MemRegion *superR,
369                                                  const TypedValueRegion *R,
370                                                  QualType Ty);
371
372  /// Get the state and region whose binding this region R corresponds to.
373  std::pair<Store, const MemRegion*>
374  GetLazyBinding(RegionBindings B, const MemRegion *R,
375                 const MemRegion *originalRegion);
376
377  StoreRef CopyLazyBindings(nonloc::LazyCompoundVal V, Store store,
378                            const TypedRegion *R);
379
380  //===------------------------------------------------------------------===//
381  // State pruning.
382  //===------------------------------------------------------------------===//
383
384  /// removeDeadBindings - Scans the RegionStore of 'state' for dead values.
385  ///  It returns a new Store with these values removed.
386  StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
387                              SymbolReaper& SymReaper);
388
389  StoreRef enterStackFrame(ProgramStateRef state,
390                           const LocationContext *callerCtx,
391                           const StackFrameContext *calleeCtx);
392
393  //===------------------------------------------------------------------===//
394  // Region "extents".
395  //===------------------------------------------------------------------===//
396
397  // FIXME: This method will soon be eliminated; see the note in Store.h.
398  DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state,
399                                         const MemRegion* R, QualType EleTy);
400
401  //===------------------------------------------------------------------===//
402  // Utility methods.
403  //===------------------------------------------------------------------===//
404
405  static inline RegionBindings GetRegionBindings(Store store) {
406    return RegionBindings(static_cast<const RegionBindings::TreeTy*>(store));
407  }
408
409  void print(Store store, raw_ostream &Out, const char* nl,
410             const char *sep);
411
412  void iterBindings(Store store, BindingsHandler& f) {
413    RegionBindings B = GetRegionBindings(store);
414    for (RegionBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I) {
415      const BindingKey &K = I.getKey();
416      if (!K.isDirect())
417        continue;
418      if (const SubRegion *R = dyn_cast<SubRegion>(I.getKey().getRegion())) {
419        // FIXME: Possibly incorporate the offset?
420        if (!f.HandleBinding(*this, store, R, I.getData()))
421          return;
422      }
423    }
424  }
425};
426
427} // end anonymous namespace
428
429//===----------------------------------------------------------------------===//
430// RegionStore creation.
431//===----------------------------------------------------------------------===//
432
433StoreManager *ento::CreateRegionStoreManager(ProgramStateManager& StMgr) {
434  RegionStoreFeatures F = maximal_features_tag();
435  return new RegionStoreManager(StMgr, F);
436}
437
438StoreManager *
439ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) {
440  RegionStoreFeatures F = minimal_features_tag();
441  F.enableFields(true);
442  return new RegionStoreManager(StMgr, F);
443}
444
445
446RegionStoreSubRegionMap*
447RegionStoreManager::getRegionStoreSubRegionMap(Store store) {
448  RegionBindings B = GetRegionBindings(store);
449  RegionStoreSubRegionMap *M = new RegionStoreSubRegionMap();
450
451  SmallVector<const SubRegion*, 10> WL;
452
453  for (RegionBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I)
454    if (const SubRegion *R = dyn_cast<SubRegion>(I.getKey().getRegion()))
455      M->process(WL, R);
456
457  // We also need to record in the subregion map "intermediate" regions that
458  // don't have direct bindings but are super regions of those that do.
459  while (!WL.empty()) {
460    const SubRegion *R = WL.back();
461    WL.pop_back();
462    M->process(WL, R);
463  }
464
465  return M;
466}
467
468//===----------------------------------------------------------------------===//
469// Region Cluster analysis.
470//===----------------------------------------------------------------------===//
471
472namespace {
473template <typename DERIVED>
474class ClusterAnalysis  {
475protected:
476  typedef BumpVector<BindingKey> RegionCluster;
477  typedef llvm::DenseMap<const MemRegion *, RegionCluster *> ClusterMap;
478  llvm::DenseMap<const RegionCluster*, unsigned> Visited;
479  typedef SmallVector<std::pair<const MemRegion *, RegionCluster*>, 10>
480    WorkList;
481
482  BumpVectorContext BVC;
483  ClusterMap ClusterM;
484  WorkList WL;
485
486  RegionStoreManager &RM;
487  ASTContext &Ctx;
488  SValBuilder &svalBuilder;
489
490  RegionBindings B;
491
492  const bool includeGlobals;
493
494public:
495  ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr,
496                  RegionBindings b, const bool includeGlobals)
497    : RM(rm), Ctx(StateMgr.getContext()),
498      svalBuilder(StateMgr.getSValBuilder()),
499      B(b), includeGlobals(includeGlobals) {}
500
501  RegionBindings getRegionBindings() const { return B; }
502
503  RegionCluster &AddToCluster(BindingKey K) {
504    const MemRegion *R = K.getRegion();
505    const MemRegion *baseR = R->getBaseRegion();
506    RegionCluster &C = getCluster(baseR);
507    C.push_back(K, BVC);
508    static_cast<DERIVED*>(this)->VisitAddedToCluster(baseR, C);
509    return C;
510  }
511
512  bool isVisited(const MemRegion *R) {
513    return (bool) Visited[&getCluster(R->getBaseRegion())];
514  }
515
516  RegionCluster& getCluster(const MemRegion *R) {
517    RegionCluster *&CRef = ClusterM[R];
518    if (!CRef) {
519      void *Mem = BVC.getAllocator().template Allocate<RegionCluster>();
520      CRef = new (Mem) RegionCluster(BVC, 10);
521    }
522    return *CRef;
523  }
524
525  void GenerateClusters() {
526      // Scan the entire set of bindings and make the region clusters.
527    for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){
528      RegionCluster &C = AddToCluster(RI.getKey());
529      if (const MemRegion *R = RI.getData().getAsRegion()) {
530        // Generate a cluster, but don't add the region to the cluster
531        // if there aren't any bindings.
532        getCluster(R->getBaseRegion());
533      }
534      if (includeGlobals) {
535        const MemRegion *R = RI.getKey().getRegion();
536        if (isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace()))
537          AddToWorkList(R, C);
538      }
539    }
540  }
541
542  bool AddToWorkList(const MemRegion *R, RegionCluster &C) {
543    if (unsigned &visited = Visited[&C])
544      return false;
545    else
546      visited = 1;
547
548    WL.push_back(std::make_pair(R, &C));
549    return true;
550  }
551
552  bool AddToWorkList(BindingKey K) {
553    return AddToWorkList(K.getRegion());
554  }
555
556  bool AddToWorkList(const MemRegion *R) {
557    const MemRegion *baseR = R->getBaseRegion();
558    return AddToWorkList(baseR, getCluster(baseR));
559  }
560
561  void RunWorkList() {
562    while (!WL.empty()) {
563      const MemRegion *baseR;
564      RegionCluster *C;
565      llvm::tie(baseR, C) = WL.back();
566      WL.pop_back();
567
568        // First visit the cluster.
569      static_cast<DERIVED*>(this)->VisitCluster(baseR, C->begin(), C->end());
570
571        // Next, visit the base region.
572      static_cast<DERIVED*>(this)->VisitBaseRegion(baseR);
573    }
574  }
575
576public:
577  void VisitAddedToCluster(const MemRegion *baseR, RegionCluster &C) {}
578  void VisitCluster(const MemRegion *baseR, BindingKey *I, BindingKey *E) {}
579  void VisitBaseRegion(const MemRegion *baseR) {}
580};
581}
582
583//===----------------------------------------------------------------------===//
584// Binding invalidation.
585//===----------------------------------------------------------------------===//
586
587void RegionStoreManager::RemoveSubRegionBindings(RegionBindings &B,
588                                                 const MemRegion *R,
589                                                 RegionStoreSubRegionMap &M) {
590
591  if (const RegionStoreSubRegionMap::Set *S = M.getSubRegions(R))
592    for (RegionStoreSubRegionMap::Set::iterator I = S->begin(), E = S->end();
593         I != E; ++I)
594      RemoveSubRegionBindings(B, *I, M);
595
596  B = removeBinding(B, R);
597}
598
599namespace {
600class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker>
601{
602  const Expr *Ex;
603  unsigned Count;
604  const LocationContext *LCtx;
605  StoreManager::InvalidatedSymbols &IS;
606  StoreManager::InvalidatedRegions *Regions;
607public:
608  invalidateRegionsWorker(RegionStoreManager &rm,
609                          ProgramStateManager &stateMgr,
610                          RegionBindings b,
611                          const Expr *ex, unsigned count,
612                          const LocationContext *lctx,
613                          StoreManager::InvalidatedSymbols &is,
614                          StoreManager::InvalidatedRegions *r,
615                          bool includeGlobals)
616    : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, includeGlobals),
617      Ex(ex), Count(count), LCtx(lctx), IS(is), Regions(r) {}
618
619  void VisitCluster(const MemRegion *baseR, BindingKey *I, BindingKey *E);
620  void VisitBaseRegion(const MemRegion *baseR);
621
622private:
623  void VisitBinding(SVal V);
624};
625}
626
627void invalidateRegionsWorker::VisitBinding(SVal V) {
628  // A symbol?  Mark it touched by the invalidation.
629  if (SymbolRef Sym = V.getAsSymbol())
630    IS.insert(Sym);
631
632  if (const MemRegion *R = V.getAsRegion()) {
633    AddToWorkList(R);
634    return;
635  }
636
637  // Is it a LazyCompoundVal?  All references get invalidated as well.
638  if (const nonloc::LazyCompoundVal *LCS =
639        dyn_cast<nonloc::LazyCompoundVal>(&V)) {
640
641    const MemRegion *LazyR = LCS->getRegion();
642    RegionBindings B = RegionStoreManager::GetRegionBindings(LCS->getStore());
643
644    for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){
645      const SubRegion *baseR = dyn_cast<SubRegion>(RI.getKey().getRegion());
646      if (baseR && (baseR == LazyR || baseR->isSubRegionOf(LazyR)))
647        VisitBinding(RI.getData());
648    }
649
650    return;
651  }
652}
653
654void invalidateRegionsWorker::VisitCluster(const MemRegion *baseR,
655                                           BindingKey *I, BindingKey *E) {
656  for ( ; I != E; ++I) {
657    // Get the old binding.  Is it a region?  If so, add it to the worklist.
658    const BindingKey &K = *I;
659    if (const SVal *V = RM.lookup(B, K))
660      VisitBinding(*V);
661
662    B = RM.removeBinding(B, K);
663  }
664}
665
666void invalidateRegionsWorker::VisitBaseRegion(const MemRegion *baseR) {
667  // Symbolic region?  Mark that symbol touched by the invalidation.
668  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR))
669    IS.insert(SR->getSymbol());
670
671  // BlockDataRegion?  If so, invalidate captured variables that are passed
672  // by reference.
673  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) {
674    for (BlockDataRegion::referenced_vars_iterator
675         BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ;
676         BI != BE; ++BI) {
677      const VarRegion *VR = *BI;
678      const VarDecl *VD = VR->getDecl();
679      if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage()) {
680        AddToWorkList(VR);
681      }
682      else if (Loc::isLocType(VR->getValueType())) {
683        // Map the current bindings to a Store to retrieve the value
684        // of the binding.  If that binding itself is a region, we should
685        // invalidate that region.  This is because a block may capture
686        // a pointer value, but the thing pointed by that pointer may
687        // get invalidated.
688        Store store = B.getRootWithoutRetain();
689        SVal V = RM.getBinding(store, loc::MemRegionVal(VR));
690        if (const Loc *L = dyn_cast<Loc>(&V)) {
691          if (const MemRegion *LR = L->getAsRegion())
692            AddToWorkList(LR);
693        }
694      }
695    }
696    return;
697  }
698
699  // Otherwise, we have a normal data region. Record that we touched the region.
700  if (Regions)
701    Regions->push_back(baseR);
702
703  if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) {
704    // Invalidate the region by setting its default value to
705    // conjured symbol. The type of the symbol is irrelavant.
706    DefinedOrUnknownSVal V =
707      svalBuilder.getConjuredSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
708    B = RM.addBinding(B, baseR, BindingKey::Default, V);
709    return;
710  }
711
712  if (!baseR->isBoundable())
713    return;
714
715  const TypedValueRegion *TR = cast<TypedValueRegion>(baseR);
716  QualType T = TR->getValueType();
717
718    // Invalidate the binding.
719  if (T->isStructureOrClassType()) {
720    // Invalidate the region by setting its default value to
721    // conjured symbol. The type of the symbol is irrelavant.
722    DefinedOrUnknownSVal V =
723      svalBuilder.getConjuredSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
724    B = RM.addBinding(B, baseR, BindingKey::Default, V);
725    return;
726  }
727
728  if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
729      // Set the default value of the array to conjured symbol.
730    DefinedOrUnknownSVal V =
731    svalBuilder.getConjuredSymbolVal(baseR, Ex, LCtx,
732                                     AT->getElementType(), Count);
733    B = RM.addBinding(B, baseR, BindingKey::Default, V);
734    return;
735  }
736
737  if (includeGlobals &&
738      isa<NonStaticGlobalSpaceRegion>(baseR->getMemorySpace())) {
739    // If the region is a global and we are invalidating all globals,
740    // just erase the entry.  This causes all globals to be lazily
741    // symbolicated from the same base symbol.
742    B = RM.removeBinding(B, baseR);
743    return;
744  }
745
746
747  DefinedOrUnknownSVal V = svalBuilder.getConjuredSymbolVal(baseR, Ex, LCtx,
748                                                            T,Count);
749  assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
750  B = RM.addBinding(B, baseR, BindingKey::Direct, V);
751}
752
753RegionBindings RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K,
754                                                          const Expr *Ex,
755                                                          unsigned Count,
756                                                    const LocationContext *LCtx,
757                                                          RegionBindings B,
758                                            InvalidatedRegions *Invalidated) {
759  // Bind the globals memory space to a new symbol that we will use to derive
760  // the bindings for all globals.
761  const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K);
762  SVal V =
763      svalBuilder.getConjuredSymbolVal(/* SymbolTag = */ (void*) GS, Ex, LCtx,
764          /* symbol type, doesn't matter */ Ctx.IntTy,
765          Count);
766
767  B = removeBinding(B, GS);
768  B = addBinding(B, BindingKey::Make(GS, BindingKey::Default), V);
769
770  // Even if there are no bindings in the global scope, we still need to
771  // record that we touched it.
772  if (Invalidated)
773    Invalidated->push_back(GS);
774
775  return B;
776}
777
778StoreRef RegionStoreManager::invalidateRegions(Store store,
779                                            ArrayRef<const MemRegion *> Regions,
780                                               const Expr *Ex, unsigned Count,
781                                               const LocationContext *LCtx,
782                                               InvalidatedSymbols &IS,
783                                               const CallOrObjCMessage *Call,
784                                              InvalidatedRegions *Invalidated) {
785  invalidateRegionsWorker W(*this, StateMgr,
786                            RegionStoreManager::GetRegionBindings(store),
787                            Ex, Count, LCtx, IS, Invalidated, false);
788
789  // Scan the bindings and generate the clusters.
790  W.GenerateClusters();
791
792  // Add the regions to the worklist.
793  for (ArrayRef<const MemRegion *>::iterator
794       I = Regions.begin(), E = Regions.end(); I != E; ++I)
795    W.AddToWorkList(*I);
796
797  W.RunWorkList();
798
799  // Return the new bindings.
800  RegionBindings B = W.getRegionBindings();
801
802  // For all globals which are not static nor immutable: determine which global
803  // regions should be invalidated and invalidate them.
804  // TODO: This could possibly be more precise with modules.
805  //
806  // System calls invalidate only system globals.
807  if (Call && Call->isInSystemHeader()) {
808    B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
809                               Ex, Count, LCtx, B, Invalidated);
810  // Internal calls might invalidate both system and internal globals.
811  } else {
812    B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
813                               Ex, Count, LCtx, B, Invalidated);
814    B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind,
815                               Ex, Count, LCtx, B, Invalidated);
816  }
817
818  return StoreRef(B.getRootWithoutRetain(), *this);
819}
820
821//===----------------------------------------------------------------------===//
822// Extents for regions.
823//===----------------------------------------------------------------------===//
824
825DefinedOrUnknownSVal
826RegionStoreManager::getSizeInElements(ProgramStateRef state,
827                                      const MemRegion *R,
828                                      QualType EleTy) {
829  SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder);
830  const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size);
831  if (!SizeInt)
832    return UnknownVal();
833
834  CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue());
835
836  if (Ctx.getAsVariableArrayType(EleTy)) {
837    // FIXME: We need to track extra state to properly record the size
838    // of VLAs.  Returning UnknownVal here, however, is a stop-gap so that
839    // we don't have a divide-by-zero below.
840    return UnknownVal();
841  }
842
843  CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy);
844
845  // If a variable is reinterpreted as a type that doesn't fit into a larger
846  // type evenly, round it down.
847  // This is a signed value, since it's used in arithmetic with signed indices.
848  return svalBuilder.makeIntVal(RegionSize / EleSize, false);
849}
850
851//===----------------------------------------------------------------------===//
852// Location and region casting.
853//===----------------------------------------------------------------------===//
854
855/// ArrayToPointer - Emulates the "decay" of an array to a pointer
856///  type.  'Array' represents the lvalue of the array being decayed
857///  to a pointer, and the returned SVal represents the decayed
858///  version of that lvalue (i.e., a pointer to the first element of
859///  the array).  This is called by ExprEngine when evaluating casts
860///  from arrays to pointers.
861SVal RegionStoreManager::ArrayToPointer(Loc Array) {
862  if (!isa<loc::MemRegionVal>(Array))
863    return UnknownVal();
864
865  const MemRegion* R = cast<loc::MemRegionVal>(&Array)->getRegion();
866  const TypedValueRegion* ArrayR = dyn_cast<TypedValueRegion>(R);
867
868  if (!ArrayR)
869    return UnknownVal();
870
871  // Strip off typedefs from the ArrayRegion's ValueType.
872  QualType T = ArrayR->getValueType().getDesugaredType(Ctx);
873  const ArrayType *AT = cast<ArrayType>(T);
874  T = AT->getElementType();
875
876  NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
877  return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, ArrayR, Ctx));
878}
879
880SVal RegionStoreManager::evalDerivedToBase(SVal derived, QualType baseType) {
881  const CXXRecordDecl *baseDecl;
882  if (baseType->isPointerType())
883    baseDecl = baseType->getCXXRecordDeclForPointerType();
884  else
885    baseDecl = baseType->getAsCXXRecordDecl();
886
887  assert(baseDecl && "not a CXXRecordDecl?");
888
889  loc::MemRegionVal *derivedRegVal = dyn_cast<loc::MemRegionVal>(&derived);
890  if (!derivedRegVal)
891    return derived;
892
893  const MemRegion *baseReg =
894    MRMgr.getCXXBaseObjectRegion(baseDecl, derivedRegVal->getRegion());
895
896  return loc::MemRegionVal(baseReg);
897}
898
899SVal RegionStoreManager::evalDynamicCast(SVal base, QualType derivedType,
900                                         bool &Failed) {
901  Failed = false;
902
903  loc::MemRegionVal *baseRegVal = dyn_cast<loc::MemRegionVal>(&base);
904  if (!baseRegVal)
905    return UnknownVal();
906  const MemRegion *BaseRegion = baseRegVal->stripCasts();
907
908  // Assume the derived class is a pointer or a reference to a CXX record.
909  derivedType = derivedType->getPointeeType();
910  assert(!derivedType.isNull());
911  const CXXRecordDecl *DerivedDecl = derivedType->getAsCXXRecordDecl();
912  if (!DerivedDecl && !derivedType->isVoidType())
913    return UnknownVal();
914
915  // Drill down the CXXBaseObject chains, which represent upcasts (casts from
916  // derived to base).
917  const MemRegion *SR = BaseRegion;
918  while (const TypedRegion *TSR = dyn_cast_or_null<TypedRegion>(SR)) {
919    QualType BaseType = TSR->getLocationType()->getPointeeType();
920    assert(!BaseType.isNull());
921    const CXXRecordDecl *SRDecl = BaseType->getAsCXXRecordDecl();
922    if (!SRDecl)
923      return UnknownVal();
924
925    // If found the derived class, the cast succeeds.
926    if (SRDecl == DerivedDecl)
927      return loc::MemRegionVal(TSR);
928
929    // If the region type is a subclass of the derived type.
930    if (!derivedType->isVoidType() && SRDecl->isDerivedFrom(DerivedDecl)) {
931      // This occurs in two cases.
932      // 1) We are processing an upcast.
933      // 2) We are processing a downcast but we jumped directly from the
934      // ancestor to a child of the cast value, so conjure the
935      // appropriate region to represent value (the intermediate node).
936      return loc::MemRegionVal(MRMgr.getCXXBaseObjectRegion(DerivedDecl,
937                                                            BaseRegion));
938    }
939
940    // If super region is not a parent of derived class, the cast definitely
941    // fails.
942    if (!derivedType->isVoidType() &&
943        DerivedDecl->isProvablyNotDerivedFrom(SRDecl)) {
944      Failed = true;
945      return UnknownVal();
946    }
947
948    if (const CXXBaseObjectRegion *R = dyn_cast<CXXBaseObjectRegion>(TSR))
949      // Drill down the chain to get the derived classes.
950      SR = R->getSuperRegion();
951    else {
952      // We reached the bottom of the hierarchy.
953
954      // If this is a cast to void*, return the region.
955      if (derivedType->isVoidType())
956        return loc::MemRegionVal(TSR);
957
958      // We did not find the derived class. We we must be casting the base to
959      // derived, so the cast should fail.
960      Failed = true;
961      return UnknownVal();
962    }
963  }
964
965  return UnknownVal();
966}
967
968//===----------------------------------------------------------------------===//
969// Loading values from regions.
970//===----------------------------------------------------------------------===//
971
972Optional<SVal> RegionStoreManager::getDirectBinding(RegionBindings B,
973                                                    const MemRegion *R) {
974
975  if (const SVal *V = lookup(B, R, BindingKey::Direct))
976    return *V;
977
978  return Optional<SVal>();
979}
980
981Optional<SVal> RegionStoreManager::getDefaultBinding(RegionBindings B,
982                                                     const MemRegion *R) {
983  if (R->isBoundable())
984    if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R))
985      if (TR->getValueType()->isUnionType())
986        return UnknownVal();
987
988  if (const SVal *V = lookup(B, R, BindingKey::Default))
989    return *V;
990
991  return Optional<SVal>();
992}
993
994SVal RegionStoreManager::getBinding(Store store, Loc L, QualType T) {
995  assert(!isa<UnknownVal>(L) && "location unknown");
996  assert(!isa<UndefinedVal>(L) && "location undefined");
997
998  // For access to concrete addresses, return UnknownVal.  Checks
999  // for null dereferences (and similar errors) are done by checkers, not
1000  // the Store.
1001  // FIXME: We can consider lazily symbolicating such memory, but we really
1002  // should defer this when we can reason easily about symbolicating arrays
1003  // of bytes.
1004  if (isa<loc::ConcreteInt>(L)) {
1005    return UnknownVal();
1006  }
1007  if (!isa<loc::MemRegionVal>(L)) {
1008    return UnknownVal();
1009  }
1010
1011  const MemRegion *MR = cast<loc::MemRegionVal>(L).getRegion();
1012
1013  if (isa<AllocaRegion>(MR) ||
1014      isa<SymbolicRegion>(MR) ||
1015      isa<CodeTextRegion>(MR)) {
1016    if (T.isNull()) {
1017      if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
1018        T = TR->getLocationType();
1019      else {
1020        const SymbolicRegion *SR = cast<SymbolicRegion>(MR);
1021        T = SR->getSymbol()->getType(Ctx);
1022      }
1023    }
1024    MR = GetElementZeroRegion(MR, T);
1025  }
1026
1027  // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
1028  //  instead of 'Loc', and have the other Loc cases handled at a higher level.
1029  const TypedValueRegion *R = cast<TypedValueRegion>(MR);
1030  QualType RTy = R->getValueType();
1031
1032  // FIXME: We should eventually handle funny addressing.  e.g.:
1033  //
1034  //   int x = ...;
1035  //   int *p = &x;
1036  //   char *q = (char*) p;
1037  //   char c = *q;  // returns the first byte of 'x'.
1038  //
1039  // Such funny addressing will occur due to layering of regions.
1040
1041  if (RTy->isStructureOrClassType())
1042    return getBindingForStruct(store, R);
1043
1044  // FIXME: Handle unions.
1045  if (RTy->isUnionType())
1046    return UnknownVal();
1047
1048  if (RTy->isArrayType())
1049    return getBindingForArray(store, R);
1050
1051  // FIXME: handle Vector types.
1052  if (RTy->isVectorType())
1053    return UnknownVal();
1054
1055  if (const FieldRegion* FR = dyn_cast<FieldRegion>(R))
1056    return CastRetrievedVal(getBindingForField(store, FR), FR, T, false);
1057
1058  if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
1059    // FIXME: Here we actually perform an implicit conversion from the loaded
1060    // value to the element type.  Eventually we want to compose these values
1061    // more intelligently.  For example, an 'element' can encompass multiple
1062    // bound regions (e.g., several bound bytes), or could be a subset of
1063    // a larger value.
1064    return CastRetrievedVal(getBindingForElement(store, ER), ER, T, false);
1065  }
1066
1067  if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) {
1068    // FIXME: Here we actually perform an implicit conversion from the loaded
1069    // value to the ivar type.  What we should model is stores to ivars
1070    // that blow past the extent of the ivar.  If the address of the ivar is
1071    // reinterpretted, it is possible we stored a different value that could
1072    // fit within the ivar.  Either we need to cast these when storing them
1073    // or reinterpret them lazily (as we do here).
1074    return CastRetrievedVal(getBindingForObjCIvar(store, IVR), IVR, T, false);
1075  }
1076
1077  if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
1078    // FIXME: Here we actually perform an implicit conversion from the loaded
1079    // value to the variable type.  What we should model is stores to variables
1080    // that blow past the extent of the variable.  If the address of the
1081    // variable is reinterpretted, it is possible we stored a different value
1082    // that could fit within the variable.  Either we need to cast these when
1083    // storing them or reinterpret them lazily (as we do here).
1084    return CastRetrievedVal(getBindingForVar(store, VR), VR, T, false);
1085  }
1086
1087  RegionBindings B = GetRegionBindings(store);
1088  const SVal *V = lookup(B, R, BindingKey::Direct);
1089
1090  // Check if the region has a binding.
1091  if (V)
1092    return *V;
1093
1094  // The location does not have a bound value.  This means that it has
1095  // the value it had upon its creation and/or entry to the analyzed
1096  // function/method.  These are either symbolic values or 'undefined'.
1097  if (R->hasStackNonParametersStorage()) {
1098    // All stack variables are considered to have undefined values
1099    // upon creation.  All heap allocated blocks are considered to
1100    // have undefined values as well unless they are explicitly bound
1101    // to specific values.
1102    return UndefinedVal();
1103  }
1104
1105  // All other values are symbolic.
1106  return svalBuilder.getRegionValueSymbolVal(R);
1107}
1108
1109std::pair<Store, const MemRegion *>
1110RegionStoreManager::GetLazyBinding(RegionBindings B, const MemRegion *R,
1111                                   const MemRegion *originalRegion) {
1112
1113  if (originalRegion != R) {
1114    if (Optional<SVal> OV = getDefaultBinding(B, R)) {
1115      if (const nonloc::LazyCompoundVal *V =
1116          dyn_cast<nonloc::LazyCompoundVal>(OV.getPointer()))
1117        return std::make_pair(V->getStore(), V->getRegion());
1118    }
1119  }
1120
1121  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
1122    const std::pair<Store, const MemRegion *> &X =
1123      GetLazyBinding(B, ER->getSuperRegion(), originalRegion);
1124
1125    if (X.second)
1126      return std::make_pair(X.first,
1127                            MRMgr.getElementRegionWithSuper(ER, X.second));
1128  }
1129  else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
1130    const std::pair<Store, const MemRegion *> &X =
1131      GetLazyBinding(B, FR->getSuperRegion(), originalRegion);
1132
1133    if (X.second)
1134      return std::make_pair(X.first,
1135                            MRMgr.getFieldRegionWithSuper(FR, X.second));
1136  }
1137  // C++ base object region is another kind of region that we should blast
1138  // through to look for lazy compound value. It is like a field region.
1139  else if (const CXXBaseObjectRegion *baseReg =
1140                            dyn_cast<CXXBaseObjectRegion>(R)) {
1141    const std::pair<Store, const MemRegion *> &X =
1142      GetLazyBinding(B, baseReg->getSuperRegion(), originalRegion);
1143
1144    if (X.second)
1145      return std::make_pair(X.first,
1146                     MRMgr.getCXXBaseObjectRegionWithSuper(baseReg, X.second));
1147  }
1148
1149  // The NULL MemRegion indicates an non-existent lazy binding. A NULL Store is
1150  // possible for a valid lazy binding.
1151  return std::make_pair((Store) 0, (const MemRegion *) 0);
1152}
1153
1154SVal RegionStoreManager::getBindingForElement(Store store,
1155                                              const ElementRegion* R) {
1156  // We do not currently model bindings of the CompoundLiteralregion.
1157  if (isa<CompoundLiteralRegion>(R->getBaseRegion()))
1158    return UnknownVal();
1159
1160  // Check if the region has a binding.
1161  RegionBindings B = GetRegionBindings(store);
1162  if (const Optional<SVal> &V = getDirectBinding(B, R))
1163    return *V;
1164
1165  const MemRegion* superR = R->getSuperRegion();
1166
1167  // Check if the region is an element region of a string literal.
1168  if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) {
1169    // FIXME: Handle loads from strings where the literal is treated as
1170    // an integer, e.g., *((unsigned int*)"hello")
1171    QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType();
1172    if (T != Ctx.getCanonicalType(R->getElementType()))
1173      return UnknownVal();
1174
1175    const StringLiteral *Str = StrR->getStringLiteral();
1176    SVal Idx = R->getIndex();
1177    if (nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(&Idx)) {
1178      int64_t i = CI->getValue().getSExtValue();
1179      // Abort on string underrun.  This can be possible by arbitrary
1180      // clients of getBindingForElement().
1181      if (i < 0)
1182        return UndefinedVal();
1183      int64_t length = Str->getLength();
1184      // Technically, only i == length is guaranteed to be null.
1185      // However, such overflows should be caught before reaching this point;
1186      // the only time such an access would be made is if a string literal was
1187      // used to initialize a larger array.
1188      char c = (i >= length) ? '\0' : Str->getCodeUnit(i);
1189      return svalBuilder.makeIntVal(c, T);
1190    }
1191  }
1192
1193  // Check for loads from a code text region.  For such loads, just give up.
1194  if (isa<CodeTextRegion>(superR))
1195    return UnknownVal();
1196
1197  // Handle the case where we are indexing into a larger scalar object.
1198  // For example, this handles:
1199  //   int x = ...
1200  //   char *y = &x;
1201  //   return *y;
1202  // FIXME: This is a hack, and doesn't do anything really intelligent yet.
1203  const RegionRawOffset &O = R->getAsArrayOffset();
1204
1205  // If we cannot reason about the offset, return an unknown value.
1206  if (!O.getRegion())
1207    return UnknownVal();
1208
1209  if (const TypedValueRegion *baseR =
1210        dyn_cast_or_null<TypedValueRegion>(O.getRegion())) {
1211    QualType baseT = baseR->getValueType();
1212    if (baseT->isScalarType()) {
1213      QualType elemT = R->getElementType();
1214      if (elemT->isScalarType()) {
1215        if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) {
1216          if (const Optional<SVal> &V = getDirectBinding(B, superR)) {
1217            if (SymbolRef parentSym = V->getAsSymbol())
1218              return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1219
1220            if (V->isUnknownOrUndef())
1221              return *V;
1222            // Other cases: give up.  We are indexing into a larger object
1223            // that has some value, but we don't know how to handle that yet.
1224            return UnknownVal();
1225          }
1226        }
1227      }
1228    }
1229  }
1230  return getBindingForFieldOrElementCommon(store, R, R->getElementType(),
1231                                           superR);
1232}
1233
1234SVal RegionStoreManager::getBindingForField(Store store,
1235                                       const FieldRegion* R) {
1236
1237  // Check if the region has a binding.
1238  RegionBindings B = GetRegionBindings(store);
1239  if (const Optional<SVal> &V = getDirectBinding(B, R))
1240    return *V;
1241
1242  QualType Ty = R->getValueType();
1243  return getBindingForFieldOrElementCommon(store, R, Ty, R->getSuperRegion());
1244}
1245
1246Optional<SVal>
1247RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindings B,
1248                                                     const MemRegion *superR,
1249                                                     const TypedValueRegion *R,
1250                                                     QualType Ty) {
1251
1252  if (const Optional<SVal> &D = getDefaultBinding(B, superR)) {
1253    const SVal &val = D.getValue();
1254    if (SymbolRef parentSym = val.getAsSymbol())
1255      return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1256
1257    if (val.isZeroConstant())
1258      return svalBuilder.makeZeroVal(Ty);
1259
1260    if (val.isUnknownOrUndef())
1261      return val;
1262
1263    // Lazy bindings are handled later.
1264    if (isa<nonloc::LazyCompoundVal>(val))
1265      return Optional<SVal>();
1266
1267    llvm_unreachable("Unknown default value");
1268  }
1269
1270  return Optional<SVal>();
1271}
1272
1273SVal RegionStoreManager::getLazyBinding(const MemRegion *lazyBindingRegion,
1274                                             Store lazyBindingStore) {
1275  if (const ElementRegion *ER = dyn_cast<ElementRegion>(lazyBindingRegion))
1276    return getBindingForElement(lazyBindingStore, ER);
1277
1278  return getBindingForField(lazyBindingStore,
1279                            cast<FieldRegion>(lazyBindingRegion));
1280}
1281
1282SVal RegionStoreManager::getBindingForFieldOrElementCommon(Store store,
1283                                                      const TypedValueRegion *R,
1284                                                      QualType Ty,
1285                                                      const MemRegion *superR) {
1286
1287  // At this point we have already checked in either getBindingForElement or
1288  // getBindingForField if 'R' has a direct binding.
1289  RegionBindings B = GetRegionBindings(store);
1290
1291  // Lazy binding?
1292  Store lazyBindingStore = NULL;
1293  const MemRegion *lazyBindingRegion = NULL;
1294  llvm::tie(lazyBindingStore, lazyBindingRegion) = GetLazyBinding(B, R, R);
1295
1296  if (lazyBindingRegion)
1297    return getLazyBinding(lazyBindingRegion, lazyBindingStore);
1298
1299  // Record whether or not we see a symbolic index.  That can completely
1300  // be out of scope of our lookup.
1301  bool hasSymbolicIndex = false;
1302
1303  while (superR) {
1304    if (const Optional<SVal> &D =
1305        getBindingForDerivedDefaultValue(B, superR, R, Ty))
1306      return *D;
1307
1308    if (const ElementRegion *ER = dyn_cast<ElementRegion>(superR)) {
1309      NonLoc index = ER->getIndex();
1310      if (!index.isConstant())
1311        hasSymbolicIndex = true;
1312    }
1313
1314    // If our super region is a field or element itself, walk up the region
1315    // hierarchy to see if there is a default value installed in an ancestor.
1316    if (const SubRegion *SR = dyn_cast<SubRegion>(superR)) {
1317      superR = SR->getSuperRegion();
1318      continue;
1319    }
1320    break;
1321  }
1322
1323  if (R->hasStackNonParametersStorage()) {
1324    if (isa<ElementRegion>(R)) {
1325      // Currently we don't reason specially about Clang-style vectors.  Check
1326      // if superR is a vector and if so return Unknown.
1327      if (const TypedValueRegion *typedSuperR =
1328            dyn_cast<TypedValueRegion>(superR)) {
1329        if (typedSuperR->getValueType()->isVectorType())
1330          return UnknownVal();
1331      }
1332    }
1333
1334    // FIXME: We also need to take ElementRegions with symbolic indexes into
1335    // account.  This case handles both directly accessing an ElementRegion
1336    // with a symbolic offset, but also fields within an element with
1337    // a symbolic offset.
1338    if (hasSymbolicIndex)
1339      return UnknownVal();
1340
1341    return UndefinedVal();
1342  }
1343
1344  // All other values are symbolic.
1345  return svalBuilder.getRegionValueSymbolVal(R);
1346}
1347
1348SVal RegionStoreManager::getBindingForObjCIvar(Store store,
1349                                               const ObjCIvarRegion* R) {
1350
1351    // Check if the region has a binding.
1352  RegionBindings B = GetRegionBindings(store);
1353
1354  if (const Optional<SVal> &V = getDirectBinding(B, R))
1355    return *V;
1356
1357  const MemRegion *superR = R->getSuperRegion();
1358
1359  // Check if the super region has a default binding.
1360  if (const Optional<SVal> &V = getDefaultBinding(B, superR)) {
1361    if (SymbolRef parentSym = V->getAsSymbol())
1362      return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1363
1364    // Other cases: give up.
1365    return UnknownVal();
1366  }
1367
1368  return getBindingForLazySymbol(R);
1369}
1370
1371SVal RegionStoreManager::getBindingForVar(Store store, const VarRegion *R) {
1372
1373  // Check if the region has a binding.
1374  RegionBindings B = GetRegionBindings(store);
1375
1376  if (const Optional<SVal> &V = getDirectBinding(B, R))
1377    return *V;
1378
1379  // Lazily derive a value for the VarRegion.
1380  const VarDecl *VD = R->getDecl();
1381  QualType T = VD->getType();
1382  const MemSpaceRegion *MS = R->getMemorySpace();
1383
1384  if (isa<UnknownSpaceRegion>(MS) ||
1385      isa<StackArgumentsSpaceRegion>(MS))
1386    return svalBuilder.getRegionValueSymbolVal(R);
1387
1388  if (isa<GlobalsSpaceRegion>(MS)) {
1389    if (isa<NonStaticGlobalSpaceRegion>(MS)) {
1390      // Is 'VD' declared constant?  If so, retrieve the constant value.
1391      QualType CT = Ctx.getCanonicalType(T);
1392      if (CT.isConstQualified()) {
1393        const Expr *Init = VD->getInit();
1394        // Do the null check first, as we want to call 'IgnoreParenCasts'.
1395        if (Init)
1396          if (const IntegerLiteral *IL =
1397              dyn_cast<IntegerLiteral>(Init->IgnoreParenCasts())) {
1398            const nonloc::ConcreteInt &V = svalBuilder.makeIntVal(IL);
1399            return svalBuilder.evalCast(V, Init->getType(), IL->getType());
1400          }
1401      }
1402
1403      if (const Optional<SVal> &V
1404            = getBindingForDerivedDefaultValue(B, MS, R, CT))
1405        return V.getValue();
1406
1407      return svalBuilder.getRegionValueSymbolVal(R);
1408    }
1409
1410    if (T->isIntegerType())
1411      return svalBuilder.makeIntVal(0, T);
1412    if (T->isPointerType())
1413      return svalBuilder.makeNull();
1414
1415    return UnknownVal();
1416  }
1417
1418  return UndefinedVal();
1419}
1420
1421SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
1422  // All other values are symbolic.
1423  return svalBuilder.getRegionValueSymbolVal(R);
1424}
1425
1426SVal RegionStoreManager::getBindingForStruct(Store store,
1427                                        const TypedValueRegion* R) {
1428  assert(R->getValueType()->isStructureOrClassType());
1429
1430  // If we already have a lazy binding, don't create a new one.
1431  RegionBindings B = GetRegionBindings(store);
1432  BindingKey K = BindingKey::Make(R, BindingKey::Default);
1433  if (const nonloc::LazyCompoundVal *V =
1434      dyn_cast_or_null<nonloc::LazyCompoundVal>(lookup(B, K))) {
1435    return *V;
1436  }
1437
1438  return svalBuilder.makeLazyCompoundVal(StoreRef(store, *this), R);
1439}
1440
1441SVal RegionStoreManager::getBindingForArray(Store store,
1442                                       const TypedValueRegion * R) {
1443  assert(Ctx.getAsConstantArrayType(R->getValueType()));
1444
1445  // If we already have a lazy binding, don't create a new one.
1446  RegionBindings B = GetRegionBindings(store);
1447  BindingKey K = BindingKey::Make(R, BindingKey::Default);
1448  if (const nonloc::LazyCompoundVal *V =
1449      dyn_cast_or_null<nonloc::LazyCompoundVal>(lookup(B, K))) {
1450    return *V;
1451  }
1452
1453  return svalBuilder.makeLazyCompoundVal(StoreRef(store, *this), R);
1454}
1455
1456bool RegionStoreManager::includedInBindings(Store store,
1457                                            const MemRegion *region) const {
1458  RegionBindings B = GetRegionBindings(store);
1459  region = region->getBaseRegion();
1460
1461  for (RegionBindings::iterator it = B.begin(), ei = B.end(); it != ei; ++it) {
1462    const BindingKey &K = it.getKey();
1463    if (region == K.getRegion())
1464      return true;
1465    const SVal &D = it.getData();
1466    if (const MemRegion *r = D.getAsRegion())
1467      if (r == region)
1468        return true;
1469  }
1470  return false;
1471}
1472
1473//===----------------------------------------------------------------------===//
1474// Binding values to regions.
1475//===----------------------------------------------------------------------===//
1476
1477StoreRef RegionStoreManager::Remove(Store store, Loc L) {
1478  if (isa<loc::MemRegionVal>(L))
1479    if (const MemRegion* R = cast<loc::MemRegionVal>(L).getRegion())
1480      return StoreRef(removeBinding(GetRegionBindings(store),
1481                                    R).getRootWithoutRetain(),
1482                      *this);
1483
1484  return StoreRef(store, *this);
1485}
1486
1487StoreRef RegionStoreManager::Bind(Store store, Loc L, SVal V) {
1488  if (isa<loc::ConcreteInt>(L))
1489    return StoreRef(store, *this);
1490
1491  // If we get here, the location should be a region.
1492  const MemRegion *R = cast<loc::MemRegionVal>(L).getRegion();
1493
1494  // Check if the region is a struct region.
1495  if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R))
1496    if (TR->getValueType()->isStructureOrClassType())
1497      return BindStruct(store, TR, V);
1498
1499  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
1500    if (ER->getIndex().isZeroConstant()) {
1501      if (const TypedValueRegion *superR =
1502            dyn_cast<TypedValueRegion>(ER->getSuperRegion())) {
1503        QualType superTy = superR->getValueType();
1504        // For now, just invalidate the fields of the struct/union/class.
1505        // This is for test rdar_test_7185607 in misc-ps-region-store.m.
1506        // FIXME: Precisely handle the fields of the record.
1507        if (superTy->isStructureOrClassType())
1508          return KillStruct(store, superR, UnknownVal());
1509      }
1510    }
1511  }
1512  else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
1513    // Binding directly to a symbolic region should be treated as binding
1514    // to element 0.
1515    QualType T = SR->getSymbol()->getType(Ctx);
1516
1517    // FIXME: Is this the right way to handle symbols that are references?
1518    if (const PointerType *PT = T->getAs<PointerType>())
1519      T = PT->getPointeeType();
1520    else
1521      T = T->getAs<ReferenceType>()->getPointeeType();
1522
1523    R = GetElementZeroRegion(SR, T);
1524  }
1525
1526  // Perform the binding.
1527  RegionBindings B = GetRegionBindings(store);
1528  return StoreRef(addBinding(B, R, BindingKey::Direct,
1529                             V).getRootWithoutRetain(), *this);
1530}
1531
1532StoreRef RegionStoreManager::BindDecl(Store store, const VarRegion *VR,
1533                                      SVal InitVal) {
1534
1535  QualType T = VR->getDecl()->getType();
1536
1537  if (T->isArrayType())
1538    return BindArray(store, VR, InitVal);
1539  if (T->isStructureOrClassType())
1540    return BindStruct(store, VR, InitVal);
1541
1542  return Bind(store, svalBuilder.makeLoc(VR), InitVal);
1543}
1544
1545// FIXME: this method should be merged into Bind().
1546StoreRef RegionStoreManager::BindCompoundLiteral(Store store,
1547                                                 const CompoundLiteralExpr *CL,
1548                                                 const LocationContext *LC,
1549                                                 SVal V) {
1550  return Bind(store, loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)),
1551              V);
1552}
1553
1554StoreRef RegionStoreManager::setImplicitDefaultValue(Store store,
1555                                                     const MemRegion *R,
1556                                                     QualType T) {
1557  RegionBindings B = GetRegionBindings(store);
1558  SVal V;
1559
1560  if (Loc::isLocType(T))
1561    V = svalBuilder.makeNull();
1562  else if (T->isIntegerType())
1563    V = svalBuilder.makeZeroVal(T);
1564  else if (T->isStructureOrClassType() || T->isArrayType()) {
1565    // Set the default value to a zero constant when it is a structure
1566    // or array.  The type doesn't really matter.
1567    V = svalBuilder.makeZeroVal(Ctx.IntTy);
1568  }
1569  else {
1570    // We can't represent values of this type, but we still need to set a value
1571    // to record that the region has been initialized.
1572    // If this assertion ever fires, a new case should be added above -- we
1573    // should know how to default-initialize any value we can symbolicate.
1574    assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
1575    V = UnknownVal();
1576  }
1577
1578  return StoreRef(addBinding(B, R, BindingKey::Default,
1579                             V).getRootWithoutRetain(), *this);
1580}
1581
1582StoreRef RegionStoreManager::BindArray(Store store, const TypedValueRegion* R,
1583                                       SVal Init) {
1584
1585  const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType()));
1586  QualType ElementTy = AT->getElementType();
1587  Optional<uint64_t> Size;
1588
1589  if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT))
1590    Size = CAT->getSize().getZExtValue();
1591
1592  // Check if the init expr is a string literal.
1593  if (loc::MemRegionVal *MRV = dyn_cast<loc::MemRegionVal>(&Init)) {
1594    const StringRegion *S = cast<StringRegion>(MRV->getRegion());
1595
1596    // Treat the string as a lazy compound value.
1597    nonloc::LazyCompoundVal LCV =
1598      cast<nonloc::LazyCompoundVal>(svalBuilder.
1599                                makeLazyCompoundVal(StoreRef(store, *this), S));
1600    return CopyLazyBindings(LCV, store, R);
1601  }
1602
1603  // Handle lazy compound values.
1604  if (nonloc::LazyCompoundVal *LCV = dyn_cast<nonloc::LazyCompoundVal>(&Init))
1605    return CopyLazyBindings(*LCV, store, R);
1606
1607  // Remaining case: explicit compound values.
1608
1609  if (Init.isUnknown())
1610    return setImplicitDefaultValue(store, R, ElementTy);
1611
1612  nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(Init);
1613  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
1614  uint64_t i = 0;
1615
1616  StoreRef newStore(store, *this);
1617  for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) {
1618    // The init list might be shorter than the array length.
1619    if (VI == VE)
1620      break;
1621
1622    const NonLoc &Idx = svalBuilder.makeArrayIndex(i);
1623    const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx);
1624
1625    if (ElementTy->isStructureOrClassType())
1626      newStore = BindStruct(newStore.getStore(), ER, *VI);
1627    else if (ElementTy->isArrayType())
1628      newStore = BindArray(newStore.getStore(), ER, *VI);
1629    else
1630      newStore = Bind(newStore.getStore(), svalBuilder.makeLoc(ER), *VI);
1631  }
1632
1633  // If the init list is shorter than the array length, set the
1634  // array default value.
1635  if (Size.hasValue() && i < Size.getValue())
1636    newStore = setImplicitDefaultValue(newStore.getStore(), R, ElementTy);
1637
1638  return newStore;
1639}
1640
1641StoreRef RegionStoreManager::BindStruct(Store store, const TypedValueRegion* R,
1642                                        SVal V) {
1643
1644  if (!Features.supportsFields())
1645    return StoreRef(store, *this);
1646
1647  QualType T = R->getValueType();
1648  assert(T->isStructureOrClassType());
1649
1650  const RecordType* RT = T->getAs<RecordType>();
1651  RecordDecl *RD = RT->getDecl();
1652
1653  if (!RD->isCompleteDefinition())
1654    return StoreRef(store, *this);
1655
1656  // Handle lazy compound values.
1657  if (const nonloc::LazyCompoundVal *LCV=dyn_cast<nonloc::LazyCompoundVal>(&V))
1658    return CopyLazyBindings(*LCV, store, R);
1659
1660  // We may get non-CompoundVal accidentally due to imprecise cast logic or
1661  // that we are binding symbolic struct value. Kill the field values, and if
1662  // the value is symbolic go and bind it as a "default" binding.
1663  if (V.isUnknown() || !isa<nonloc::CompoundVal>(V)) {
1664    SVal SV = isa<nonloc::SymbolVal>(V) ? V : UnknownVal();
1665    return KillStruct(store, R, SV);
1666  }
1667
1668  nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(V);
1669  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
1670
1671  RecordDecl::field_iterator FI, FE;
1672  StoreRef newStore(store, *this);
1673
1674  for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
1675
1676    if (VI == VE)
1677      break;
1678
1679    // Skip any unnamed bitfields to stay in sync with the initializers.
1680    if (FI->isUnnamedBitfield())
1681      continue;
1682
1683    QualType FTy = FI->getType();
1684    const FieldRegion* FR = MRMgr.getFieldRegion(&*FI, R);
1685
1686    if (FTy->isArrayType())
1687      newStore = BindArray(newStore.getStore(), FR, *VI);
1688    else if (FTy->isStructureOrClassType())
1689      newStore = BindStruct(newStore.getStore(), FR, *VI);
1690    else
1691      newStore = Bind(newStore.getStore(), svalBuilder.makeLoc(FR), *VI);
1692    ++VI;
1693  }
1694
1695  // There may be fewer values in the initialize list than the fields of struct.
1696  if (FI != FE) {
1697    RegionBindings B = GetRegionBindings(newStore.getStore());
1698    B = addBinding(B, R, BindingKey::Default, svalBuilder.makeIntVal(0, false));
1699    newStore = StoreRef(B.getRootWithoutRetain(), *this);
1700  }
1701
1702  return newStore;
1703}
1704
1705StoreRef RegionStoreManager::KillStruct(Store store, const TypedRegion* R,
1706                                     SVal DefaultVal) {
1707  BindingKey key = BindingKey::Make(R, BindingKey::Default);
1708
1709  // The BindingKey may be "invalid" if we cannot handle the region binding
1710  // explicitly.  One example is something like array[index], where index
1711  // is a symbolic value.  In such cases, we want to invalidate the entire
1712  // array, as the index assignment could have been to any element.  In
1713  // the case of nested symbolic indices, we need to march up the region
1714  // hierarchy untile we reach a region whose binding we can reason about.
1715  const SubRegion *subReg = R;
1716
1717  while (!key.isValid()) {
1718    if (const SubRegion *tmp = dyn_cast<SubRegion>(subReg->getSuperRegion())) {
1719      subReg = tmp;
1720      key = BindingKey::Make(tmp, BindingKey::Default);
1721    }
1722    else
1723      break;
1724  }
1725
1726  // Remove the old bindings, using 'subReg' as the root of all regions
1727  // we will invalidate.
1728  RegionBindings B = GetRegionBindings(store);
1729  OwningPtr<RegionStoreSubRegionMap>
1730    SubRegions(getRegionStoreSubRegionMap(store));
1731  RemoveSubRegionBindings(B, subReg, *SubRegions);
1732
1733  // Set the default value of the struct region to "unknown".
1734  if (!key.isValid())
1735    return StoreRef(B.getRootWithoutRetain(), *this);
1736
1737  return StoreRef(addBinding(B, key, DefaultVal).getRootWithoutRetain(), *this);
1738}
1739
1740StoreRef RegionStoreManager::CopyLazyBindings(nonloc::LazyCompoundVal V,
1741                                              Store store,
1742                                              const TypedRegion *R) {
1743
1744  // Nuke the old bindings stemming from R.
1745  RegionBindings B = GetRegionBindings(store);
1746
1747  OwningPtr<RegionStoreSubRegionMap>
1748    SubRegions(getRegionStoreSubRegionMap(store));
1749
1750  // B and DVM are updated after the call to RemoveSubRegionBindings.
1751  RemoveSubRegionBindings(B, R, *SubRegions.get());
1752
1753  // Now copy the bindings.  This amounts to just binding 'V' to 'R'.  This
1754  // results in a zero-copy algorithm.
1755  return StoreRef(addBinding(B, R, BindingKey::Default,
1756                             V).getRootWithoutRetain(), *this);
1757}
1758
1759//===----------------------------------------------------------------------===//
1760// "Raw" retrievals and bindings.
1761//===----------------------------------------------------------------------===//
1762
1763
1764RegionBindings RegionStoreManager::addBinding(RegionBindings B, BindingKey K,
1765                                              SVal V) {
1766  if (!K.isValid())
1767    return B;
1768  return RBFactory.add(B, K, V);
1769}
1770
1771RegionBindings RegionStoreManager::addBinding(RegionBindings B,
1772                                              const MemRegion *R,
1773                                              BindingKey::Kind k, SVal V) {
1774  return addBinding(B, BindingKey::Make(R, k), V);
1775}
1776
1777const SVal *RegionStoreManager::lookup(RegionBindings B, BindingKey K) {
1778  if (!K.isValid())
1779    return NULL;
1780  return B.lookup(K);
1781}
1782
1783const SVal *RegionStoreManager::lookup(RegionBindings B,
1784                                       const MemRegion *R,
1785                                       BindingKey::Kind k) {
1786  return lookup(B, BindingKey::Make(R, k));
1787}
1788
1789RegionBindings RegionStoreManager::removeBinding(RegionBindings B,
1790                                                 BindingKey K) {
1791  if (!K.isValid())
1792    return B;
1793  return RBFactory.remove(B, K);
1794}
1795
1796RegionBindings RegionStoreManager::removeBinding(RegionBindings B,
1797                                                 const MemRegion *R,
1798                                                BindingKey::Kind k){
1799  return removeBinding(B, BindingKey::Make(R, k));
1800}
1801
1802//===----------------------------------------------------------------------===//
1803// State pruning.
1804//===----------------------------------------------------------------------===//
1805
1806namespace {
1807class removeDeadBindingsWorker :
1808  public ClusterAnalysis<removeDeadBindingsWorker> {
1809  SmallVector<const SymbolicRegion*, 12> Postponed;
1810  SymbolReaper &SymReaper;
1811  const StackFrameContext *CurrentLCtx;
1812
1813public:
1814  removeDeadBindingsWorker(RegionStoreManager &rm,
1815                           ProgramStateManager &stateMgr,
1816                           RegionBindings b, SymbolReaper &symReaper,
1817                           const StackFrameContext *LCtx)
1818    : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b,
1819                                                /* includeGlobals = */ false),
1820      SymReaper(symReaper), CurrentLCtx(LCtx) {}
1821
1822  // Called by ClusterAnalysis.
1823  void VisitAddedToCluster(const MemRegion *baseR, RegionCluster &C);
1824  void VisitCluster(const MemRegion *baseR, BindingKey *I, BindingKey *E);
1825
1826  void VisitBindingKey(BindingKey K);
1827  bool UpdatePostponed();
1828  void VisitBinding(SVal V);
1829};
1830}
1831
1832void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
1833                                                   RegionCluster &C) {
1834
1835  if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) {
1836    if (SymReaper.isLive(VR))
1837      AddToWorkList(baseR, C);
1838
1839    return;
1840  }
1841
1842  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) {
1843    if (SymReaper.isLive(SR->getSymbol()))
1844      AddToWorkList(SR, C);
1845    else
1846      Postponed.push_back(SR);
1847
1848    return;
1849  }
1850
1851  if (isa<NonStaticGlobalSpaceRegion>(baseR)) {
1852    AddToWorkList(baseR, C);
1853    return;
1854  }
1855
1856  // CXXThisRegion in the current or parent location context is live.
1857  if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) {
1858    const StackArgumentsSpaceRegion *StackReg =
1859      cast<StackArgumentsSpaceRegion>(TR->getSuperRegion());
1860    const StackFrameContext *RegCtx = StackReg->getStackFrame();
1861    if (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))
1862      AddToWorkList(TR, C);
1863  }
1864}
1865
1866void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
1867                                            BindingKey *I, BindingKey *E) {
1868  for ( ; I != E; ++I)
1869    VisitBindingKey(*I);
1870}
1871
1872void removeDeadBindingsWorker::VisitBinding(SVal V) {
1873  // Is it a LazyCompoundVal?  All referenced regions are live as well.
1874  if (const nonloc::LazyCompoundVal *LCS =
1875      dyn_cast<nonloc::LazyCompoundVal>(&V)) {
1876
1877    const MemRegion *LazyR = LCS->getRegion();
1878    RegionBindings B = RegionStoreManager::GetRegionBindings(LCS->getStore());
1879    for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){
1880      const SubRegion *baseR = dyn_cast<SubRegion>(RI.getKey().getRegion());
1881      if (baseR && baseR->isSubRegionOf(LazyR))
1882        VisitBinding(RI.getData());
1883    }
1884    return;
1885  }
1886
1887  // If V is a region, then add it to the worklist.
1888  if (const MemRegion *R = V.getAsRegion())
1889    AddToWorkList(R);
1890
1891  // Update the set of live symbols.
1892  for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end();
1893       SI!=SE; ++SI)
1894    SymReaper.markLive(*SI);
1895}
1896
1897void removeDeadBindingsWorker::VisitBindingKey(BindingKey K) {
1898  const MemRegion *R = K.getRegion();
1899
1900  // Mark this region "live" by adding it to the worklist.  This will cause
1901  // use to visit all regions in the cluster (if we haven't visited them
1902  // already).
1903  if (AddToWorkList(R)) {
1904    // Mark the symbol for any live SymbolicRegion as "live".  This means we
1905    // should continue to track that symbol.
1906    if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(R))
1907      SymReaper.markLive(SymR->getSymbol());
1908
1909    // For BlockDataRegions, enqueue the VarRegions for variables marked
1910    // with __block (passed-by-reference).
1911    // via BlockDeclRefExprs.
1912    if (const BlockDataRegion *BD = dyn_cast<BlockDataRegion>(R)) {
1913      for (BlockDataRegion::referenced_vars_iterator
1914           RI = BD->referenced_vars_begin(), RE = BD->referenced_vars_end();
1915           RI != RE; ++RI) {
1916        if ((*RI)->getDecl()->getAttr<BlocksAttr>())
1917          AddToWorkList(*RI);
1918      }
1919
1920      // No possible data bindings on a BlockDataRegion.
1921      return;
1922    }
1923  }
1924
1925  // Visit the data binding for K.
1926  if (const SVal *V = RM.lookup(B, K))
1927    VisitBinding(*V);
1928}
1929
1930bool removeDeadBindingsWorker::UpdatePostponed() {
1931  // See if any postponed SymbolicRegions are actually live now, after
1932  // having done a scan.
1933  bool changed = false;
1934
1935  for (SmallVectorImpl<const SymbolicRegion*>::iterator
1936        I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) {
1937    if (const SymbolicRegion *SR = cast_or_null<SymbolicRegion>(*I)) {
1938      if (SymReaper.isLive(SR->getSymbol())) {
1939        changed |= AddToWorkList(SR);
1940        *I = NULL;
1941      }
1942    }
1943  }
1944
1945  return changed;
1946}
1947
1948StoreRef RegionStoreManager::removeDeadBindings(Store store,
1949                                                const StackFrameContext *LCtx,
1950                                                SymbolReaper& SymReaper) {
1951  RegionBindings B = GetRegionBindings(store);
1952  removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
1953  W.GenerateClusters();
1954
1955  // Enqueue the region roots onto the worklist.
1956  for (SymbolReaper::region_iterator I = SymReaper.region_begin(),
1957       E = SymReaper.region_end(); I != E; ++I) {
1958    W.AddToWorkList(*I);
1959  }
1960
1961  do W.RunWorkList(); while (W.UpdatePostponed());
1962
1963  // We have now scanned the store, marking reachable regions and symbols
1964  // as live.  We now remove all the regions that are dead from the store
1965  // as well as update DSymbols with the set symbols that are now dead.
1966  for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) {
1967    const BindingKey &K = I.getKey();
1968
1969    // If the cluster has been visited, we know the region has been marked.
1970    if (W.isVisited(K.getRegion()))
1971      continue;
1972
1973    // Remove the dead entry.
1974    B = removeBinding(B, K);
1975
1976    // Mark all non-live symbols that this binding references as dead.
1977    if (const SymbolicRegion* SymR = dyn_cast<SymbolicRegion>(K.getRegion()))
1978      SymReaper.maybeDead(SymR->getSymbol());
1979
1980    SVal X = I.getData();
1981    SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end();
1982    for (; SI != SE; ++SI)
1983      SymReaper.maybeDead(*SI);
1984  }
1985
1986  return StoreRef(B.getRootWithoutRetain(), *this);
1987}
1988
1989
1990StoreRef RegionStoreManager::enterStackFrame(ProgramStateRef state,
1991                                             const LocationContext *callerCtx,
1992                                             const StackFrameContext *calleeCtx)
1993{
1994  FunctionDecl const *FD = cast<FunctionDecl>(calleeCtx->getDecl());
1995  FunctionDecl::param_const_iterator PI = FD->param_begin(),
1996                                     PE = FD->param_end();
1997  StoreRef store = StoreRef(state->getStore(), *this);
1998
1999  if (CallExpr const *CE = dyn_cast<CallExpr>(calleeCtx->getCallSite())) {
2000    CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end();
2001
2002    // Copy the arg expression value to the arg variables.  We check that
2003    // PI != PE because the actual number of arguments may be different than
2004    // the function declaration.
2005    for (; AI != AE && PI != PE; ++AI, ++PI) {
2006      SVal ArgVal = state->getSVal(*AI, callerCtx);
2007      store = Bind(store.getStore(),
2008                   svalBuilder.makeLoc(MRMgr.getVarRegion(*PI, calleeCtx)),
2009                   ArgVal);
2010    }
2011  } else if (const CXXConstructExpr *CE =
2012               dyn_cast<CXXConstructExpr>(calleeCtx->getCallSite())) {
2013    CXXConstructExpr::const_arg_iterator AI = CE->arg_begin(),
2014      AE = CE->arg_end();
2015
2016    // Copy the arg expression value to the arg variables.
2017    for (; AI != AE; ++AI, ++PI) {
2018      SVal ArgVal = state->getSVal(*AI, callerCtx);
2019      store = Bind(store.getStore(),
2020                   svalBuilder.makeLoc(MRMgr.getVarRegion(*PI, calleeCtx)),
2021                   ArgVal);
2022    }
2023  } else
2024    assert(isa<CXXDestructorDecl>(calleeCtx->getDecl()));
2025
2026  return store;
2027}
2028
2029//===----------------------------------------------------------------------===//
2030// Utility methods.
2031//===----------------------------------------------------------------------===//
2032
2033void RegionStoreManager::print(Store store, raw_ostream &OS,
2034                               const char* nl, const char *sep) {
2035  RegionBindings B = GetRegionBindings(store);
2036  OS << "Store (direct and default bindings), "
2037     << (void*) B.getRootWithoutRetain()
2038     << " :" << nl;
2039
2040  for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I)
2041    OS << ' ' << I.getKey() << " : " << I.getData() << nl;
2042}
2043