clang  7.0.0svn
RegionStore.cpp
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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 
18 #include "clang/AST/Attr.h"
19 #include "clang/AST/CharUnits.h"
22 #include "clang/Basic/TargetInfo.h"
29 #include "llvm/ADT/ImmutableMap.h"
30 #include "llvm/ADT/Optional.h"
31 #include "llvm/Support/raw_ostream.h"
32 #include <utility>
33 
34 using namespace clang;
35 using namespace ento;
36 
37 //===----------------------------------------------------------------------===//
38 // Representation of binding keys.
39 //===----------------------------------------------------------------------===//
40 
41 namespace {
42 class BindingKey {
43 public:
44  enum Kind { Default = 0x0, Direct = 0x1 };
45 private:
46  enum { Symbolic = 0x2 };
47 
48  llvm::PointerIntPair<const MemRegion *, 2> P;
49  uint64_t Data;
50 
51  /// Create a key for a binding to region \p r, which has a symbolic offset
52  /// from region \p Base.
53  explicit BindingKey(const SubRegion *r, const SubRegion *Base, Kind k)
54  : P(r, k | Symbolic), Data(reinterpret_cast<uintptr_t>(Base)) {
55  assert(r && Base && "Must have known regions.");
56  assert(getConcreteOffsetRegion() == Base && "Failed to store base region");
57  }
58 
59  /// Create a key for a binding at \p offset from base region \p r.
60  explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k)
61  : P(r, k), Data(offset) {
62  assert(r && "Must have known regions.");
63  assert(getOffset() == offset && "Failed to store offset");
64  assert((r == r->getBaseRegion() || isa<ObjCIvarRegion>(r)) && "Not a base");
65  }
66 public:
67 
68  bool isDirect() const { return P.getInt() & Direct; }
69  bool hasSymbolicOffset() const { return P.getInt() & Symbolic; }
70 
71  const MemRegion *getRegion() const { return P.getPointer(); }
72  uint64_t getOffset() const {
73  assert(!hasSymbolicOffset());
74  return Data;
75  }
76 
77  const SubRegion *getConcreteOffsetRegion() const {
78  assert(hasSymbolicOffset());
79  return reinterpret_cast<const SubRegion *>(static_cast<uintptr_t>(Data));
80  }
81 
82  const MemRegion *getBaseRegion() const {
83  if (hasSymbolicOffset())
84  return getConcreteOffsetRegion()->getBaseRegion();
85  return getRegion()->getBaseRegion();
86  }
87 
88  void Profile(llvm::FoldingSetNodeID& ID) const {
89  ID.AddPointer(P.getOpaqueValue());
90  ID.AddInteger(Data);
91  }
92 
93  static BindingKey Make(const MemRegion *R, Kind k);
94 
95  bool operator<(const BindingKey &X) const {
96  if (P.getOpaqueValue() < X.P.getOpaqueValue())
97  return true;
98  if (P.getOpaqueValue() > X.P.getOpaqueValue())
99  return false;
100  return Data < X.Data;
101  }
102 
103  bool operator==(const BindingKey &X) const {
104  return P.getOpaqueValue() == X.P.getOpaqueValue() &&
105  Data == X.Data;
106  }
107 
108  void dump() const;
109 };
110 } // end anonymous namespace
111 
112 BindingKey BindingKey::Make(const MemRegion *R, Kind k) {
113  const RegionOffset &RO = R->getAsOffset();
114  if (RO.hasSymbolicOffset())
115  return BindingKey(cast<SubRegion>(R), cast<SubRegion>(RO.getRegion()), k);
116 
117  return BindingKey(RO.getRegion(), RO.getOffset(), k);
118 }
119 
120 namespace llvm {
121  static inline
122  raw_ostream &operator<<(raw_ostream &os, BindingKey K) {
123  os << '(' << K.getRegion();
124  if (!K.hasSymbolicOffset())
125  os << ',' << K.getOffset();
126  os << ',' << (K.isDirect() ? "direct" : "default")
127  << ')';
128  return os;
129  }
130 
131  template <typename T> struct isPodLike;
132  template <> struct isPodLike<BindingKey> {
133  static const bool value = true;
134  };
135 } // end llvm namespace
136 
137 #ifndef NDEBUG
138 LLVM_DUMP_METHOD void BindingKey::dump() const { llvm::errs() << *this; }
139 #endif
140 
141 //===----------------------------------------------------------------------===//
142 // Actual Store type.
143 //===----------------------------------------------------------------------===//
144 
145 typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings;
146 typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef;
147 typedef std::pair<BindingKey, SVal> BindingPair;
148 
149 typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings>
151 
152 namespace {
153 class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *,
154  ClusterBindings> {
155  ClusterBindings::Factory *CBFactory;
156 
157 public:
158  typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>
159  ParentTy;
160 
161  RegionBindingsRef(ClusterBindings::Factory &CBFactory,
162  const RegionBindings::TreeTy *T,
163  RegionBindings::TreeTy::Factory *F)
164  : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F),
165  CBFactory(&CBFactory) {}
166 
167  RegionBindingsRef(const ParentTy &P, ClusterBindings::Factory &CBFactory)
168  : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P),
169  CBFactory(&CBFactory) {}
170 
171  RegionBindingsRef add(key_type_ref K, data_type_ref D) const {
172  return RegionBindingsRef(static_cast<const ParentTy *>(this)->add(K, D),
173  *CBFactory);
174  }
175 
176  RegionBindingsRef remove(key_type_ref K) const {
177  return RegionBindingsRef(static_cast<const ParentTy *>(this)->remove(K),
178  *CBFactory);
179  }
180 
181  RegionBindingsRef addBinding(BindingKey K, SVal V) const;
182 
183  RegionBindingsRef addBinding(const MemRegion *R,
184  BindingKey::Kind k, SVal V) const;
185 
186  const SVal *lookup(BindingKey K) const;
187  const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const;
188  using llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>::lookup;
189 
190  RegionBindingsRef removeBinding(BindingKey K);
191 
192  RegionBindingsRef removeBinding(const MemRegion *R,
193  BindingKey::Kind k);
194 
195  RegionBindingsRef removeBinding(const MemRegion *R) {
196  return removeBinding(R, BindingKey::Direct).
197  removeBinding(R, BindingKey::Default);
198  }
199 
200  Optional<SVal> getDirectBinding(const MemRegion *R) const;
201 
202  /// getDefaultBinding - Returns an SVal* representing an optional default
203  /// binding associated with a region and its subregions.
204  Optional<SVal> getDefaultBinding(const MemRegion *R) const;
205 
206  /// Return the internal tree as a Store.
207  Store asStore() const {
208  return asImmutableMap().getRootWithoutRetain();
209  }
210 
211  void dump(raw_ostream &OS, const char *nl) const {
212  for (iterator I = begin(), E = end(); I != E; ++I) {
213  const ClusterBindings &Cluster = I.getData();
214  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
215  CI != CE; ++CI) {
216  OS << ' ' << CI.getKey() << " : " << CI.getData() << nl;
217  }
218  OS << nl;
219  }
220  }
221 
222  LLVM_DUMP_METHOD void dump() const { dump(llvm::errs(), "\n"); }
223 };
224 } // end anonymous namespace
225 
226 typedef const RegionBindingsRef& RegionBindingsConstRef;
227 
228 Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const {
229  return Optional<SVal>::create(lookup(R, BindingKey::Direct));
230 }
231 
232 Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const {
233  return Optional<SVal>::create(lookup(R, BindingKey::Default));
234 }
235 
236 RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const {
237  const MemRegion *Base = K.getBaseRegion();
238 
239  const ClusterBindings *ExistingCluster = lookup(Base);
240  ClusterBindings Cluster =
241  (ExistingCluster ? *ExistingCluster : CBFactory->getEmptyMap());
242 
243  ClusterBindings NewCluster = CBFactory->add(Cluster, K, V);
244  return add(Base, NewCluster);
245 }
246 
247 
248 RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R,
249  BindingKey::Kind k,
250  SVal V) const {
251  return addBinding(BindingKey::Make(R, k), V);
252 }
253 
254 const SVal *RegionBindingsRef::lookup(BindingKey K) const {
255  const ClusterBindings *Cluster = lookup(K.getBaseRegion());
256  if (!Cluster)
257  return nullptr;
258  return Cluster->lookup(K);
259 }
260 
261 const SVal *RegionBindingsRef::lookup(const MemRegion *R,
262  BindingKey::Kind k) const {
263  return lookup(BindingKey::Make(R, k));
264 }
265 
266 RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) {
267  const MemRegion *Base = K.getBaseRegion();
268  const ClusterBindings *Cluster = lookup(Base);
269  if (!Cluster)
270  return *this;
271 
272  ClusterBindings NewCluster = CBFactory->remove(*Cluster, K);
273  if (NewCluster.isEmpty())
274  return remove(Base);
275  return add(Base, NewCluster);
276 }
277 
278 RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R,
279  BindingKey::Kind k){
280  return removeBinding(BindingKey::Make(R, k));
281 }
282 
283 //===----------------------------------------------------------------------===//
284 // Fine-grained control of RegionStoreManager.
285 //===----------------------------------------------------------------------===//
286 
287 namespace {
288 struct minimal_features_tag {};
289 struct maximal_features_tag {};
290 
291 class RegionStoreFeatures {
292  bool SupportsFields;
293 public:
294  RegionStoreFeatures(minimal_features_tag) :
295  SupportsFields(false) {}
296 
297  RegionStoreFeatures(maximal_features_tag) :
298  SupportsFields(true) {}
299 
300  void enableFields(bool t) { SupportsFields = t; }
301 
302  bool supportsFields() const { return SupportsFields; }
303 };
304 }
305 
306 //===----------------------------------------------------------------------===//
307 // Main RegionStore logic.
308 //===----------------------------------------------------------------------===//
309 
310 namespace {
311 class invalidateRegionsWorker;
312 
313 class RegionStoreManager : public StoreManager {
314 public:
315  const RegionStoreFeatures Features;
316 
317  RegionBindings::Factory RBFactory;
318  mutable ClusterBindings::Factory CBFactory;
319 
320  typedef std::vector<SVal> SValListTy;
321 private:
322  typedef llvm::DenseMap<const LazyCompoundValData *,
323  SValListTy> LazyBindingsMapTy;
324  LazyBindingsMapTy LazyBindingsMap;
325 
326  /// The largest number of fields a struct can have and still be
327  /// considered "small".
328  ///
329  /// This is currently used to decide whether or not it is worth "forcing" a
330  /// LazyCompoundVal on bind.
331  ///
332  /// This is controlled by 'region-store-small-struct-limit' option.
333  /// To disable all small-struct-dependent behavior, set the option to "0".
334  unsigned SmallStructLimit;
335 
336  /// A helper used to populate the work list with the given set of
337  /// regions.
338  void populateWorkList(invalidateRegionsWorker &W,
339  ArrayRef<SVal> Values,
340  InvalidatedRegions *TopLevelRegions);
341 
342 public:
343  RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f)
344  : StoreManager(mgr), Features(f),
345  RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()),
346  SmallStructLimit(0) {
347  if (SubEngine *Eng = StateMgr.getOwningEngine()) {
348  AnalyzerOptions &Options = Eng->getAnalysisManager().options;
349  SmallStructLimit =
350  Options.getOptionAsInteger("region-store-small-struct-limit", 2);
351  }
352  }
353 
354 
355  /// setImplicitDefaultValue - Set the default binding for the provided
356  /// MemRegion to the value implicitly defined for compound literals when
357  /// the value is not specified.
358  RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B,
359  const MemRegion *R, QualType T);
360 
361  /// ArrayToPointer - Emulates the "decay" of an array to a pointer
362  /// type. 'Array' represents the lvalue of the array being decayed
363  /// to a pointer, and the returned SVal represents the decayed
364  /// version of that lvalue (i.e., a pointer to the first element of
365  /// the array). This is called by ExprEngine when evaluating
366  /// casts from arrays to pointers.
367  SVal ArrayToPointer(Loc Array, QualType ElementTy) override;
368 
369  StoreRef getInitialStore(const LocationContext *InitLoc) override {
370  return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this);
371  }
372 
373  //===-------------------------------------------------------------------===//
374  // Binding values to regions.
375  //===-------------------------------------------------------------------===//
376  RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K,
377  const Expr *Ex,
378  unsigned Count,
379  const LocationContext *LCtx,
380  RegionBindingsRef B,
381  InvalidatedRegions *Invalidated);
382 
383  StoreRef invalidateRegions(Store store,
384  ArrayRef<SVal> Values,
385  const Expr *E, unsigned Count,
386  const LocationContext *LCtx,
387  const CallEvent *Call,
388  InvalidatedSymbols &IS,
390  InvalidatedRegions *Invalidated,
391  InvalidatedRegions *InvalidatedTopLevel) override;
392 
393  bool scanReachableSymbols(Store S, const MemRegion *R,
394  ScanReachableSymbols &Callbacks) override;
395 
396  RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B,
397  const SubRegion *R);
398 
399 public: // Part of public interface to class.
400 
401  StoreRef Bind(Store store, Loc LV, SVal V) override {
402  return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this);
403  }
404 
405  RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V);
406 
407  // BindDefaultInitial is only used to initialize a region with
408  // a default value.
409  StoreRef BindDefaultInitial(Store store, const MemRegion *R,
410  SVal V) override {
411  RegionBindingsRef B = getRegionBindings(store);
412  // Use other APIs when you have to wipe the region that was initialized
413  // earlier.
414  assert(!(B.getDefaultBinding(R) || B.getDirectBinding(R)) &&
415  "Double initialization!");
416  B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
417  return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
418  }
419 
420  // BindDefaultZero is used for zeroing constructors that may accidentally
421  // overwrite existing bindings.
422  StoreRef BindDefaultZero(Store store, const MemRegion *R) override {
423  // FIXME: The offsets of empty bases can be tricky because of
424  // of the so called "empty base class optimization".
425  // If a base class has been optimized out
426  // we should not try to create a binding, otherwise we should.
427  // Unfortunately, at the moment ASTRecordLayout doesn't expose
428  // the actual sizes of the empty bases
429  // and trying to infer them from offsets/alignments
430  // seems to be error-prone and non-trivial because of the trailing padding.
431  // As a temporary mitigation we don't create bindings for empty bases.
432  if (const auto *BR = dyn_cast<CXXBaseObjectRegion>(R))
433  if (BR->getDecl()->isEmpty())
434  return StoreRef(store, *this);
435 
436  RegionBindingsRef B = getRegionBindings(store);
437  SVal V = svalBuilder.makeZeroVal(Ctx.CharTy);
438  B = removeSubRegionBindings(B, cast<SubRegion>(R));
439  B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
440  return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
441  }
442 
443  /// Attempt to extract the fields of \p LCV and bind them to the struct region
444  /// \p R.
445  ///
446  /// This path is used when it seems advantageous to "force" loading the values
447  /// within a LazyCompoundVal to bind memberwise to the struct region, rather
448  /// than using a Default binding at the base of the entire region. This is a
449  /// heuristic attempting to avoid building long chains of LazyCompoundVals.
450  ///
451  /// \returns The updated store bindings, or \c None if binding non-lazily
452  /// would be too expensive.
453  Optional<RegionBindingsRef> tryBindSmallStruct(RegionBindingsConstRef B,
454  const TypedValueRegion *R,
455  const RecordDecl *RD,
457 
458  /// BindStruct - Bind a compound value to a structure.
459  RegionBindingsRef bindStruct(RegionBindingsConstRef B,
460  const TypedValueRegion* R, SVal V);
461 
462  /// BindVector - Bind a compound value to a vector.
463  RegionBindingsRef bindVector(RegionBindingsConstRef B,
464  const TypedValueRegion* R, SVal V);
465 
466  RegionBindingsRef bindArray(RegionBindingsConstRef B,
467  const TypedValueRegion* R,
468  SVal V);
469 
470  /// Clears out all bindings in the given region and assigns a new value
471  /// as a Default binding.
472  RegionBindingsRef bindAggregate(RegionBindingsConstRef B,
473  const TypedRegion *R,
474  SVal DefaultVal);
475 
476  /// Create a new store with the specified binding removed.
477  /// \param ST the original store, that is the basis for the new store.
478  /// \param L the location whose binding should be removed.
479  StoreRef killBinding(Store ST, Loc L) override;
480 
481  void incrementReferenceCount(Store store) override {
482  getRegionBindings(store).manualRetain();
483  }
484 
485  /// If the StoreManager supports it, decrement the reference count of
486  /// the specified Store object. If the reference count hits 0, the memory
487  /// associated with the object is recycled.
488  void decrementReferenceCount(Store store) override {
489  getRegionBindings(store).manualRelease();
490  }
491 
492  bool includedInBindings(Store store, const MemRegion *region) const override;
493 
494  /// Return the value bound to specified location in a given state.
495  ///
496  /// The high level logic for this method is this:
497  /// getBinding (L)
498  /// if L has binding
499  /// return L's binding
500  /// else if L is in killset
501  /// return unknown
502  /// else
503  /// if L is on stack or heap
504  /// return undefined
505  /// else
506  /// return symbolic
507  SVal getBinding(Store S, Loc L, QualType T) override {
508  return getBinding(getRegionBindings(S), L, T);
509  }
510 
511  Optional<SVal> getDefaultBinding(Store S, const MemRegion *R) override {
512  RegionBindingsRef B = getRegionBindings(S);
513  // Default bindings are always applied over a base region so look up the
514  // base region's default binding, otherwise the lookup will fail when R
515  // is at an offset from R->getBaseRegion().
516  return B.getDefaultBinding(R->getBaseRegion());
517  }
518 
519  SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType());
520 
521  SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R);
522 
523  SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R);
524 
525  SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R);
526 
527  SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R);
528 
529  SVal getBindingForLazySymbol(const TypedValueRegion *R);
530 
531  SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
532  const TypedValueRegion *R,
533  QualType Ty);
534 
535  SVal getLazyBinding(const SubRegion *LazyBindingRegion,
536  RegionBindingsRef LazyBinding);
537 
538  /// Get bindings for the values in a struct and return a CompoundVal, used
539  /// when doing struct copy:
540  /// struct s x, y;
541  /// x = y;
542  /// y's value is retrieved by this method.
543  SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R);
544  SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R);
545  NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R);
546 
547  /// Used to lazily generate derived symbols for bindings that are defined
548  /// implicitly by default bindings in a super region.
549  ///
550  /// Note that callers may need to specially handle LazyCompoundVals, which
551  /// are returned as is in case the caller needs to treat them differently.
552  Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
553  const MemRegion *superR,
554  const TypedValueRegion *R,
555  QualType Ty);
556 
557  /// Get the state and region whose binding this region \p R corresponds to.
558  ///
559  /// If there is no lazy binding for \p R, the returned value will have a null
560  /// \c second. Note that a null pointer can represents a valid Store.
561  std::pair<Store, const SubRegion *>
562  findLazyBinding(RegionBindingsConstRef B, const SubRegion *R,
563  const SubRegion *originalRegion);
564 
565  /// Returns the cached set of interesting SVals contained within a lazy
566  /// binding.
567  ///
568  /// The precise value of "interesting" is determined for the purposes of
569  /// RegionStore's internal analysis. It must always contain all regions and
570  /// symbols, but may omit constants and other kinds of SVal.
571  const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV);
572 
573  //===------------------------------------------------------------------===//
574  // State pruning.
575  //===------------------------------------------------------------------===//
576 
577  /// removeDeadBindings - Scans the RegionStore of 'state' for dead values.
578  /// It returns a new Store with these values removed.
579  StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
580  SymbolReaper& SymReaper) override;
581 
582  //===------------------------------------------------------------------===//
583  // Region "extents".
584  //===------------------------------------------------------------------===//
585 
586  // FIXME: This method will soon be eliminated; see the note in Store.h.
587  DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state,
588  const MemRegion* R,
589  QualType EleTy) override;
590 
591  //===------------------------------------------------------------------===//
592  // Utility methods.
593  //===------------------------------------------------------------------===//
594 
595  RegionBindingsRef getRegionBindings(Store store) const {
596  return RegionBindingsRef(CBFactory,
597  static_cast<const RegionBindings::TreeTy*>(store),
598  RBFactory.getTreeFactory());
599  }
600 
601  void print(Store store, raw_ostream &Out, const char* nl,
602  const char *sep) override;
603 
604  void iterBindings(Store store, BindingsHandler& f) override {
605  RegionBindingsRef B = getRegionBindings(store);
606  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
607  const ClusterBindings &Cluster = I.getData();
608  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
609  CI != CE; ++CI) {
610  const BindingKey &K = CI.getKey();
611  if (!K.isDirect())
612  continue;
613  if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) {
614  // FIXME: Possibly incorporate the offset?
615  if (!f.HandleBinding(*this, store, R, CI.getData()))
616  return;
617  }
618  }
619  }
620  }
621 };
622 
623 } // end anonymous namespace
624 
625 //===----------------------------------------------------------------------===//
626 // RegionStore creation.
627 //===----------------------------------------------------------------------===//
628 
629 std::unique_ptr<StoreManager>
631  RegionStoreFeatures F = maximal_features_tag();
632  return llvm::make_unique<RegionStoreManager>(StMgr, F);
633 }
634 
635 std::unique_ptr<StoreManager>
637  RegionStoreFeatures F = minimal_features_tag();
638  F.enableFields(true);
639  return llvm::make_unique<RegionStoreManager>(StMgr, F);
640 }
641 
642 
643 //===----------------------------------------------------------------------===//
644 // Region Cluster analysis.
645 //===----------------------------------------------------------------------===//
646 
647 namespace {
648 /// Used to determine which global regions are automatically included in the
649 /// initial worklist of a ClusterAnalysis.
651  /// Don't include any global regions.
652  GFK_None,
653  /// Only include system globals.
654  GFK_SystemOnly,
655  /// Include all global regions.
656  GFK_All
657 };
658 
659 template <typename DERIVED>
660 class ClusterAnalysis {
661 protected:
662  typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap;
663  typedef const MemRegion * WorkListElement;
665 
666  llvm::SmallPtrSet<const ClusterBindings *, 16> Visited;
667 
668  WorkList WL;
669 
670  RegionStoreManager &RM;
671  ASTContext &Ctx;
672  SValBuilder &svalBuilder;
673 
674  RegionBindingsRef B;
675 
676 
677 protected:
678  const ClusterBindings *getCluster(const MemRegion *R) {
679  return B.lookup(R);
680  }
681 
682  /// Returns true if all clusters in the given memspace should be initially
683  /// included in the cluster analysis. Subclasses may provide their
684  /// own implementation.
685  bool includeEntireMemorySpace(const MemRegion *Base) {
686  return false;
687  }
688 
689 public:
690  ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr,
691  RegionBindingsRef b)
692  : RM(rm), Ctx(StateMgr.getContext()),
693  svalBuilder(StateMgr.getSValBuilder()), B(std::move(b)) {}
694 
695  RegionBindingsRef getRegionBindings() const { return B; }
696 
697  bool isVisited(const MemRegion *R) {
698  return Visited.count(getCluster(R));
699  }
700 
701  void GenerateClusters() {
702  // Scan the entire set of bindings and record the region clusters.
703  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end();
704  RI != RE; ++RI){
705  const MemRegion *Base = RI.getKey();
706 
707  const ClusterBindings &Cluster = RI.getData();
708  assert(!Cluster.isEmpty() && "Empty clusters should be removed");
709  static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster);
710 
711  // If the base's memspace should be entirely invalidated, add the cluster
712  // to the workspace up front.
713  if (static_cast<DERIVED*>(this)->includeEntireMemorySpace(Base))
714  AddToWorkList(WorkListElement(Base), &Cluster);
715  }
716  }
717 
718  bool AddToWorkList(WorkListElement E, const ClusterBindings *C) {
719  if (C && !Visited.insert(C).second)
720  return false;
721  WL.push_back(E);
722  return true;
723  }
724 
725  bool AddToWorkList(const MemRegion *R) {
726  return static_cast<DERIVED*>(this)->AddToWorkList(R);
727  }
728 
729  void RunWorkList() {
730  while (!WL.empty()) {
731  WorkListElement E = WL.pop_back_val();
732  const MemRegion *BaseR = E;
733 
734  static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR));
735  }
736  }
737 
738  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {}
739  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {}
740 
741  void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C,
742  bool Flag) {
743  static_cast<DERIVED*>(this)->VisitCluster(BaseR, C);
744  }
745 };
746 }
747 
748 //===----------------------------------------------------------------------===//
749 // Binding invalidation.
750 //===----------------------------------------------------------------------===//
751 
752 bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R,
753  ScanReachableSymbols &Callbacks) {
754  assert(R == R->getBaseRegion() && "Should only be called for base regions");
755  RegionBindingsRef B = getRegionBindings(S);
756  const ClusterBindings *Cluster = B.lookup(R);
757 
758  if (!Cluster)
759  return true;
760 
761  for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end();
762  RI != RE; ++RI) {
763  if (!Callbacks.scan(RI.getData()))
764  return false;
765  }
766 
767  return true;
768 }
769 
770 static inline bool isUnionField(const FieldRegion *FR) {
771  return FR->getDecl()->getParent()->isUnion();
772 }
773 
775 
776 static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) {
777  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
778 
779  const MemRegion *Base = K.getConcreteOffsetRegion();
780  const MemRegion *R = K.getRegion();
781 
782  while (R != Base) {
783  if (const FieldRegion *FR = dyn_cast<FieldRegion>(R))
784  if (!isUnionField(FR))
785  Fields.push_back(FR->getDecl());
786 
787  R = cast<SubRegion>(R)->getSuperRegion();
788  }
789 }
790 
791 static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) {
792  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
793 
794  if (Fields.empty())
795  return true;
796 
797  FieldVector FieldsInBindingKey;
798  getSymbolicOffsetFields(K, FieldsInBindingKey);
799 
800  ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size();
801  if (Delta >= 0)
802  return std::equal(FieldsInBindingKey.begin() + Delta,
803  FieldsInBindingKey.end(),
804  Fields.begin());
805  else
806  return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(),
807  Fields.begin() - Delta);
808 }
809 
810 /// Collects all bindings in \p Cluster that may refer to bindings within
811 /// \p Top.
812 ///
813 /// Each binding is a pair whose \c first is the key (a BindingKey) and whose
814 /// \c second is the value (an SVal).
815 ///
816 /// The \p IncludeAllDefaultBindings parameter specifies whether to include
817 /// default bindings that may extend beyond \p Top itself, e.g. if \p Top is
818 /// an aggregate within a larger aggregate with a default binding.
819 static void
821  SValBuilder &SVB, const ClusterBindings &Cluster,
822  const SubRegion *Top, BindingKey TopKey,
823  bool IncludeAllDefaultBindings) {
824  FieldVector FieldsInSymbolicSubregions;
825  if (TopKey.hasSymbolicOffset()) {
826  getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions);
827  Top = TopKey.getConcreteOffsetRegion();
828  TopKey = BindingKey::Make(Top, BindingKey::Default);
829  }
830 
831  // Find the length (in bits) of the region being invalidated.
832  uint64_t Length = UINT64_MAX;
833  SVal Extent = Top->getExtent(SVB);
834  if (Optional<nonloc::ConcreteInt> ExtentCI =
835  Extent.getAs<nonloc::ConcreteInt>()) {
836  const llvm::APSInt &ExtentInt = ExtentCI->getValue();
837  assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned());
838  // Extents are in bytes but region offsets are in bits. Be careful!
839  Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth();
840  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) {
841  if (FR->getDecl()->isBitField())
842  Length = FR->getDecl()->getBitWidthValue(SVB.getContext());
843  }
844 
845  for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end();
846  I != E; ++I) {
847  BindingKey NextKey = I.getKey();
848  if (NextKey.getRegion() == TopKey.getRegion()) {
849  // FIXME: This doesn't catch the case where we're really invalidating a
850  // region with a symbolic offset. Example:
851  // R: points[i].y
852  // Next: points[0].x
853 
854  if (NextKey.getOffset() > TopKey.getOffset() &&
855  NextKey.getOffset() - TopKey.getOffset() < Length) {
856  // Case 1: The next binding is inside the region we're invalidating.
857  // Include it.
858  Bindings.push_back(*I);
859 
860  } else if (NextKey.getOffset() == TopKey.getOffset()) {
861  // Case 2: The next binding is at the same offset as the region we're
862  // invalidating. In this case, we need to leave default bindings alone,
863  // since they may be providing a default value for a regions beyond what
864  // we're invalidating.
865  // FIXME: This is probably incorrect; consider invalidating an outer
866  // struct whose first field is bound to a LazyCompoundVal.
867  if (IncludeAllDefaultBindings || NextKey.isDirect())
868  Bindings.push_back(*I);
869  }
870 
871  } else if (NextKey.hasSymbolicOffset()) {
872  const MemRegion *Base = NextKey.getConcreteOffsetRegion();
873  if (Top->isSubRegionOf(Base) && Top != Base) {
874  // Case 3: The next key is symbolic and we just changed something within
875  // its concrete region. We don't know if the binding is still valid, so
876  // we'll be conservative and include it.
877  if (IncludeAllDefaultBindings || NextKey.isDirect())
878  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
879  Bindings.push_back(*I);
880  } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) {
881  // Case 4: The next key is symbolic, but we changed a known
882  // super-region. In this case the binding is certainly included.
883  if (BaseSR->isSubRegionOf(Top))
884  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
885  Bindings.push_back(*I);
886  }
887  }
888  }
889 }
890 
891 static void
893  SValBuilder &SVB, const ClusterBindings &Cluster,
894  const SubRegion *Top, bool IncludeAllDefaultBindings) {
895  collectSubRegionBindings(Bindings, SVB, Cluster, Top,
897  IncludeAllDefaultBindings);
898 }
899 
900 RegionBindingsRef
901 RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B,
902  const SubRegion *Top) {
903  BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default);
904  const MemRegion *ClusterHead = TopKey.getBaseRegion();
905 
906  if (Top == ClusterHead) {
907  // We can remove an entire cluster's bindings all in one go.
908  return B.remove(Top);
909  }
910 
911  const ClusterBindings *Cluster = B.lookup(ClusterHead);
912  if (!Cluster) {
913  // If we're invalidating a region with a symbolic offset, we need to make
914  // sure we don't treat the base region as uninitialized anymore.
915  if (TopKey.hasSymbolicOffset()) {
916  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
917  return B.addBinding(Concrete, BindingKey::Default, UnknownVal());
918  }
919  return B;
920  }
921 
923  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey,
924  /*IncludeAllDefaultBindings=*/false);
925 
926  ClusterBindingsRef Result(*Cluster, CBFactory);
927  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
928  E = Bindings.end();
929  I != E; ++I)
930  Result = Result.remove(I->first);
931 
932  // If we're invalidating a region with a symbolic offset, we need to make sure
933  // we don't treat the base region as uninitialized anymore.
934  // FIXME: This isn't very precise; see the example in
935  // collectSubRegionBindings.
936  if (TopKey.hasSymbolicOffset()) {
937  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
938  Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default),
939  UnknownVal());
940  }
941 
942  if (Result.isEmpty())
943  return B.remove(ClusterHead);
944  return B.add(ClusterHead, Result.asImmutableMap());
945 }
946 
947 namespace {
948 class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker>
949 {
950  const Expr *Ex;
951  unsigned Count;
952  const LocationContext *LCtx;
953  InvalidatedSymbols &IS;
956  GlobalsFilterKind GlobalsFilter;
957 public:
958  invalidateRegionsWorker(RegionStoreManager &rm,
959  ProgramStateManager &stateMgr,
960  RegionBindingsRef b,
961  const Expr *ex, unsigned count,
962  const LocationContext *lctx,
963  InvalidatedSymbols &is,
966  GlobalsFilterKind GFK)
967  : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b),
968  Ex(ex), Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r),
969  GlobalsFilter(GFK) {}
970 
971  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
972  void VisitBinding(SVal V);
973 
974  using ClusterAnalysis::AddToWorkList;
975 
976  bool AddToWorkList(const MemRegion *R);
977 
978  /// Returns true if all clusters in the memory space for \p Base should be
979  /// be invalidated.
980  bool includeEntireMemorySpace(const MemRegion *Base);
981 
982  /// Returns true if the memory space of the given region is one of the global
983  /// regions specially included at the start of invalidation.
984  bool isInitiallyIncludedGlobalRegion(const MemRegion *R);
985 };
986 }
987 
988 bool invalidateRegionsWorker::AddToWorkList(const MemRegion *R) {
989  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
991  const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion();
992  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
993 }
994 
995 void invalidateRegionsWorker::VisitBinding(SVal V) {
996  // A symbol? Mark it touched by the invalidation.
997  if (SymbolRef Sym = V.getAsSymbol())
998  IS.insert(Sym);
999 
1000  if (const MemRegion *R = V.getAsRegion()) {
1001  AddToWorkList(R);
1002  return;
1003  }
1004 
1005  // Is it a LazyCompoundVal? All references get invalidated as well.
1008 
1009  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
1010 
1011  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
1012  E = Vals.end();
1013  I != E; ++I)
1014  VisitBinding(*I);
1015 
1016  return;
1017  }
1018 }
1019 
1020 void invalidateRegionsWorker::VisitCluster(const MemRegion *baseR,
1021  const ClusterBindings *C) {
1022 
1023  bool PreserveRegionsContents =
1024  ITraits.hasTrait(baseR,
1026 
1027  if (C) {
1028  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I)
1029  VisitBinding(I.getData());
1030 
1031  // Invalidate regions contents.
1032  if (!PreserveRegionsContents)
1033  B = B.remove(baseR);
1034  }
1035 
1036  // BlockDataRegion? If so, invalidate captured variables that are passed
1037  // by reference.
1038  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) {
1040  BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ;
1041  BI != BE; ++BI) {
1042  const VarRegion *VR = BI.getCapturedRegion();
1043  const VarDecl *VD = VR->getDecl();
1044  if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage()) {
1045  AddToWorkList(VR);
1046  }
1047  else if (Loc::isLocType(VR->getValueType())) {
1048  // Map the current bindings to a Store to retrieve the value
1049  // of the binding. If that binding itself is a region, we should
1050  // invalidate that region. This is because a block may capture
1051  // a pointer value, but the thing pointed by that pointer may
1052  // get invalidated.
1053  SVal V = RM.getBinding(B, loc::MemRegionVal(VR));
1054  if (Optional<Loc> L = V.getAs<Loc>()) {
1055  if (const MemRegion *LR = L->getAsRegion())
1056  AddToWorkList(LR);
1057  }
1058  }
1059  }
1060  return;
1061  }
1062 
1063  // Symbolic region?
1064  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR))
1065  IS.insert(SR->getSymbol());
1066 
1067  // Nothing else should be done in the case when we preserve regions context.
1068  if (PreserveRegionsContents)
1069  return;
1070 
1071  // Otherwise, we have a normal data region. Record that we touched the region.
1072  if (Regions)
1073  Regions->push_back(baseR);
1074 
1075  if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) {
1076  // Invalidate the region by setting its default value to
1077  // conjured symbol. The type of the symbol is irrelevant.
1079  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
1080  B = B.addBinding(baseR, BindingKey::Default, V);
1081  return;
1082  }
1083 
1084  if (!baseR->isBoundable())
1085  return;
1086 
1087  const TypedValueRegion *TR = cast<TypedValueRegion>(baseR);
1088  QualType T = TR->getValueType();
1089 
1090  if (isInitiallyIncludedGlobalRegion(baseR)) {
1091  // If the region is a global and we are invalidating all globals,
1092  // erasing the entry is good enough. This causes all globals to be lazily
1093  // symbolicated from the same base symbol.
1094  return;
1095  }
1096 
1097  if (T->isRecordType()) {
1098  // Invalidate the region by setting its default value to
1099  // conjured symbol. The type of the symbol is irrelevant.
1100  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1101  Ctx.IntTy, Count);
1102  B = B.addBinding(baseR, BindingKey::Default, V);
1103  return;
1104  }
1105 
1106  if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
1107  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1108  baseR,
1110 
1111  if (doNotInvalidateSuperRegion) {
1112  // We are not doing blank invalidation of the whole array region so we
1113  // have to manually invalidate each elements.
1114  Optional<uint64_t> NumElements;
1115 
1116  // Compute lower and upper offsets for region within array.
1117  if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT))
1118  NumElements = CAT->getSize().getZExtValue();
1119  if (!NumElements) // We are not dealing with a constant size array
1120  goto conjure_default;
1121  QualType ElementTy = AT->getElementType();
1122  uint64_t ElemSize = Ctx.getTypeSize(ElementTy);
1123  const RegionOffset &RO = baseR->getAsOffset();
1124  const MemRegion *SuperR = baseR->getBaseRegion();
1125  if (RO.hasSymbolicOffset()) {
1126  // If base region has a symbolic offset,
1127  // we revert to invalidating the super region.
1128  if (SuperR)
1129  AddToWorkList(SuperR);
1130  goto conjure_default;
1131  }
1132 
1133  uint64_t LowerOffset = RO.getOffset();
1134  uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize;
1135  bool UpperOverflow = UpperOffset < LowerOffset;
1136 
1137  // Invalidate regions which are within array boundaries,
1138  // or have a symbolic offset.
1139  if (!SuperR)
1140  goto conjure_default;
1141 
1142  const ClusterBindings *C = B.lookup(SuperR);
1143  if (!C)
1144  goto conjure_default;
1145 
1146  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E;
1147  ++I) {
1148  const BindingKey &BK = I.getKey();
1149  Optional<uint64_t> ROffset =
1150  BK.hasSymbolicOffset() ? Optional<uint64_t>() : BK.getOffset();
1151 
1152  // Check offset is not symbolic and within array's boundaries.
1153  // Handles arrays of 0 elements and of 0-sized elements as well.
1154  if (!ROffset ||
1155  ((*ROffset >= LowerOffset && *ROffset < UpperOffset) ||
1156  (UpperOverflow &&
1157  (*ROffset >= LowerOffset || *ROffset < UpperOffset)) ||
1158  (LowerOffset == UpperOffset && *ROffset == LowerOffset))) {
1159  B = B.removeBinding(I.getKey());
1160  // Bound symbolic regions need to be invalidated for dead symbol
1161  // detection.
1162  SVal V = I.getData();
1163  const MemRegion *R = V.getAsRegion();
1164  if (R && isa<SymbolicRegion>(R))
1165  VisitBinding(V);
1166  }
1167  }
1168  }
1169  conjure_default:
1170  // Set the default value of the array to conjured symbol.
1172  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1173  AT->getElementType(), Count);
1174  B = B.addBinding(baseR, BindingKey::Default, V);
1175  return;
1176  }
1177 
1178  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1179  T,Count);
1180  assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
1181  B = B.addBinding(baseR, BindingKey::Direct, V);
1182 }
1183 
1184 bool invalidateRegionsWorker::isInitiallyIncludedGlobalRegion(
1185  const MemRegion *R) {
1186  switch (GlobalsFilter) {
1187  case GFK_None:
1188  return false;
1189  case GFK_SystemOnly:
1190  return isa<GlobalSystemSpaceRegion>(R->getMemorySpace());
1191  case GFK_All:
1192  return isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace());
1193  }
1194 
1195  llvm_unreachable("unknown globals filter");
1196 }
1197 
1198 bool invalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) {
1199  if (isInitiallyIncludedGlobalRegion(Base))
1200  return true;
1201 
1202  const MemSpaceRegion *MemSpace = Base->getMemorySpace();
1203  return ITraits.hasTrait(MemSpace,
1205 }
1206 
1207 RegionBindingsRef
1208 RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K,
1209  const Expr *Ex,
1210  unsigned Count,
1211  const LocationContext *LCtx,
1212  RegionBindingsRef B,
1213  InvalidatedRegions *Invalidated) {
1214  // Bind the globals memory space to a new symbol that we will use to derive
1215  // the bindings for all globals.
1216  const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K);
1217  SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx,
1218  /* type does not matter */ Ctx.IntTy,
1219  Count);
1220 
1221  B = B.removeBinding(GS)
1222  .addBinding(BindingKey::Make(GS, BindingKey::Default), V);
1223 
1224  // Even if there are no bindings in the global scope, we still need to
1225  // record that we touched it.
1226  if (Invalidated)
1227  Invalidated->push_back(GS);
1228 
1229  return B;
1230 }
1231 
1232 void RegionStoreManager::populateWorkList(invalidateRegionsWorker &W,
1233  ArrayRef<SVal> Values,
1234  InvalidatedRegions *TopLevelRegions) {
1235  for (ArrayRef<SVal>::iterator I = Values.begin(),
1236  E = Values.end(); I != E; ++I) {
1237  SVal V = *I;
1240 
1241  const SValListTy &Vals = getInterestingValues(*LCS);
1242 
1243  for (SValListTy::const_iterator I = Vals.begin(),
1244  E = Vals.end(); I != E; ++I) {
1245  // Note: the last argument is false here because these are
1246  // non-top-level regions.
1247  if (const MemRegion *R = (*I).getAsRegion())
1248  W.AddToWorkList(R);
1249  }
1250  continue;
1251  }
1252 
1253  if (const MemRegion *R = V.getAsRegion()) {
1254  if (TopLevelRegions)
1255  TopLevelRegions->push_back(R);
1256  W.AddToWorkList(R);
1257  continue;
1258  }
1259  }
1260 }
1261 
1262 StoreRef
1263 RegionStoreManager::invalidateRegions(Store store,
1264  ArrayRef<SVal> Values,
1265  const Expr *Ex, unsigned Count,
1266  const LocationContext *LCtx,
1267  const CallEvent *Call,
1268  InvalidatedSymbols &IS,
1270  InvalidatedRegions *TopLevelRegions,
1271  InvalidatedRegions *Invalidated) {
1272  GlobalsFilterKind GlobalsFilter;
1273  if (Call) {
1274  if (Call->isInSystemHeader())
1275  GlobalsFilter = GFK_SystemOnly;
1276  else
1277  GlobalsFilter = GFK_All;
1278  } else {
1279  GlobalsFilter = GFK_None;
1280  }
1281 
1282  RegionBindingsRef B = getRegionBindings(store);
1283  invalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, ITraits,
1284  Invalidated, GlobalsFilter);
1285 
1286  // Scan the bindings and generate the clusters.
1287  W.GenerateClusters();
1288 
1289  // Add the regions to the worklist.
1290  populateWorkList(W, Values, TopLevelRegions);
1291 
1292  W.RunWorkList();
1293 
1294  // Return the new bindings.
1295  B = W.getRegionBindings();
1296 
1297  // For calls, determine which global regions should be invalidated and
1298  // invalidate them. (Note that function-static and immutable globals are never
1299  // invalidated by this.)
1300  // TODO: This could possibly be more precise with modules.
1301  switch (GlobalsFilter) {
1302  case GFK_All:
1303  B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind,
1304  Ex, Count, LCtx, B, Invalidated);
1305  // FALLTHROUGH
1306  case GFK_SystemOnly:
1307  B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
1308  Ex, Count, LCtx, B, Invalidated);
1309  // FALLTHROUGH
1310  case GFK_None:
1311  break;
1312  }
1313 
1314  return StoreRef(B.asStore(), *this);
1315 }
1316 
1317 //===----------------------------------------------------------------------===//
1318 // Extents for regions.
1319 //===----------------------------------------------------------------------===//
1320 
1322 RegionStoreManager::getSizeInElements(ProgramStateRef state,
1323  const MemRegion *R,
1324  QualType EleTy) {
1325  SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder);
1326  const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size);
1327  if (!SizeInt)
1328  return UnknownVal();
1329 
1330  CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue());
1331 
1332  if (Ctx.getAsVariableArrayType(EleTy)) {
1333  // FIXME: We need to track extra state to properly record the size
1334  // of VLAs. Returning UnknownVal here, however, is a stop-gap so that
1335  // we don't have a divide-by-zero below.
1336  return UnknownVal();
1337  }
1338 
1339  CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy);
1340 
1341  // If a variable is reinterpreted as a type that doesn't fit into a larger
1342  // type evenly, round it down.
1343  // This is a signed value, since it's used in arithmetic with signed indices.
1344  return svalBuilder.makeIntVal(RegionSize / EleSize, false);
1345 }
1346 
1347 //===----------------------------------------------------------------------===//
1348 // Location and region casting.
1349 //===----------------------------------------------------------------------===//
1350 
1351 /// ArrayToPointer - Emulates the "decay" of an array to a pointer
1352 /// type. 'Array' represents the lvalue of the array being decayed
1353 /// to a pointer, and the returned SVal represents the decayed
1354 /// version of that lvalue (i.e., a pointer to the first element of
1355 /// the array). This is called by ExprEngine when evaluating casts
1356 /// from arrays to pointers.
1357 SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) {
1358  if (Array.getAs<loc::ConcreteInt>())
1359  return Array;
1360 
1361  if (!Array.getAs<loc::MemRegionVal>())
1362  return UnknownVal();
1363 
1364  const SubRegion *R =
1365  cast<SubRegion>(Array.castAs<loc::MemRegionVal>().getRegion());
1366  NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
1367  return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, R, Ctx));
1368 }
1369 
1370 //===----------------------------------------------------------------------===//
1371 // Loading values from regions.
1372 //===----------------------------------------------------------------------===//
1373 
1374 SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) {
1375  assert(!L.getAs<UnknownVal>() && "location unknown");
1376  assert(!L.getAs<UndefinedVal>() && "location undefined");
1377 
1378  // For access to concrete addresses, return UnknownVal. Checks
1379  // for null dereferences (and similar errors) are done by checkers, not
1380  // the Store.
1381  // FIXME: We can consider lazily symbolicating such memory, but we really
1382  // should defer this when we can reason easily about symbolicating arrays
1383  // of bytes.
1384  if (L.getAs<loc::ConcreteInt>()) {
1385  return UnknownVal();
1386  }
1387  if (!L.getAs<loc::MemRegionVal>()) {
1388  return UnknownVal();
1389  }
1390 
1391  const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion();
1392 
1393  if (isa<BlockDataRegion>(MR)) {
1394  return UnknownVal();
1395  }
1396 
1397  if (!isa<TypedValueRegion>(MR)) {
1398  if (T.isNull()) {
1399  if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
1400  T = TR->getLocationType()->getPointeeType();
1401  else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1402  T = SR->getSymbol()->getType()->getPointeeType();
1403  }
1404  assert(!T.isNull() && "Unable to auto-detect binding type!");
1405  assert(!T->isVoidType() && "Attempting to dereference a void pointer!");
1406  MR = GetElementZeroRegion(cast<SubRegion>(MR), T);
1407  } else {
1408  T = cast<TypedValueRegion>(MR)->getValueType();
1409  }
1410 
1411  // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
1412  // instead of 'Loc', and have the other Loc cases handled at a higher level.
1413  const TypedValueRegion *R = cast<TypedValueRegion>(MR);
1414  QualType RTy = R->getValueType();
1415 
1416  // FIXME: we do not yet model the parts of a complex type, so treat the
1417  // whole thing as "unknown".
1418  if (RTy->isAnyComplexType())
1419  return UnknownVal();
1420 
1421  // FIXME: We should eventually handle funny addressing. e.g.:
1422  //
1423  // int x = ...;
1424  // int *p = &x;
1425  // char *q = (char*) p;
1426  // char c = *q; // returns the first byte of 'x'.
1427  //
1428  // Such funny addressing will occur due to layering of regions.
1429  if (RTy->isStructureOrClassType())
1430  return getBindingForStruct(B, R);
1431 
1432  // FIXME: Handle unions.
1433  if (RTy->isUnionType())
1434  return createLazyBinding(B, R);
1435 
1436  if (RTy->isArrayType()) {
1437  if (RTy->isConstantArrayType())
1438  return getBindingForArray(B, R);
1439  else
1440  return UnknownVal();
1441  }
1442 
1443  // FIXME: handle Vector types.
1444  if (RTy->isVectorType())
1445  return UnknownVal();
1446 
1447  if (const FieldRegion* FR = dyn_cast<FieldRegion>(R))
1448  return CastRetrievedVal(getBindingForField(B, FR), FR, T);
1449 
1450  if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
1451  // FIXME: Here we actually perform an implicit conversion from the loaded
1452  // value to the element type. Eventually we want to compose these values
1453  // more intelligently. For example, an 'element' can encompass multiple
1454  // bound regions (e.g., several bound bytes), or could be a subset of
1455  // a larger value.
1456  return CastRetrievedVal(getBindingForElement(B, ER), ER, T);
1457  }
1458 
1459  if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) {
1460  // FIXME: Here we actually perform an implicit conversion from the loaded
1461  // value to the ivar type. What we should model is stores to ivars
1462  // that blow past the extent of the ivar. If the address of the ivar is
1463  // reinterpretted, it is possible we stored a different value that could
1464  // fit within the ivar. Either we need to cast these when storing them
1465  // or reinterpret them lazily (as we do here).
1466  return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T);
1467  }
1468 
1469  if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
1470  // FIXME: Here we actually perform an implicit conversion from the loaded
1471  // value to the variable type. What we should model is stores to variables
1472  // that blow past the extent of the variable. If the address of the
1473  // variable is reinterpretted, it is possible we stored a different value
1474  // that could fit within the variable. Either we need to cast these when
1475  // storing them or reinterpret them lazily (as we do here).
1476  return CastRetrievedVal(getBindingForVar(B, VR), VR, T);
1477  }
1478 
1479  const SVal *V = B.lookup(R, BindingKey::Direct);
1480 
1481  // Check if the region has a binding.
1482  if (V)
1483  return *V;
1484 
1485  // The location does not have a bound value. This means that it has
1486  // the value it had upon its creation and/or entry to the analyzed
1487  // function/method. These are either symbolic values or 'undefined'.
1488  if (R->hasStackNonParametersStorage()) {
1489  // All stack variables are considered to have undefined values
1490  // upon creation. All heap allocated blocks are considered to
1491  // have undefined values as well unless they are explicitly bound
1492  // to specific values.
1493  return UndefinedVal();
1494  }
1495 
1496  // All other values are symbolic.
1497  return svalBuilder.getRegionValueSymbolVal(R);
1498 }
1499 
1501  QualType RegionTy;
1502  if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R))
1503  RegionTy = TVR->getValueType();
1504 
1505  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1506  RegionTy = SR->getSymbol()->getType();
1507 
1508  return RegionTy;
1509 }
1510 
1511 /// Checks to see if store \p B has a lazy binding for region \p R.
1512 ///
1513 /// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected
1514 /// if there are additional bindings within \p R.
1515 ///
1516 /// Note that unlike RegionStoreManager::findLazyBinding, this will not search
1517 /// for lazy bindings for super-regions of \p R.
1519 getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B,
1520  const SubRegion *R, bool AllowSubregionBindings) {
1521  Optional<SVal> V = B.getDefaultBinding(R);
1522  if (!V)
1523  return None;
1524 
1526  if (!LCV)
1527  return None;
1528 
1529  // If the LCV is for a subregion, the types might not match, and we shouldn't
1530  // reuse the binding.
1531  QualType RegionTy = getUnderlyingType(R);
1532  if (!RegionTy.isNull() &&
1533  !RegionTy->isVoidPointerType()) {
1534  QualType SourceRegionTy = LCV->getRegion()->getValueType();
1535  if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy))
1536  return None;
1537  }
1538 
1539  if (!AllowSubregionBindings) {
1540  // If there are any other bindings within this region, we shouldn't reuse
1541  // the top-level binding.
1543  collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R,
1544  /*IncludeAllDefaultBindings=*/true);
1545  if (Bindings.size() > 1)
1546  return None;
1547  }
1548 
1549  return *LCV;
1550 }
1551 
1552 
1553 std::pair<Store, const SubRegion *>
1554 RegionStoreManager::findLazyBinding(RegionBindingsConstRef B,
1555  const SubRegion *R,
1556  const SubRegion *originalRegion) {
1557  if (originalRegion != R) {
1559  getExistingLazyBinding(svalBuilder, B, R, true))
1560  return std::make_pair(V->getStore(), V->getRegion());
1561  }
1562 
1563  typedef std::pair<Store, const SubRegion *> StoreRegionPair;
1564  StoreRegionPair Result = StoreRegionPair();
1565 
1566  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
1567  Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()),
1568  originalRegion);
1569 
1570  if (Result.second)
1571  Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second);
1572 
1573  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
1574  Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()),
1575  originalRegion);
1576 
1577  if (Result.second)
1578  Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second);
1579 
1580  } else if (const CXXBaseObjectRegion *BaseReg =
1581  dyn_cast<CXXBaseObjectRegion>(R)) {
1582  // C++ base object region is another kind of region that we should blast
1583  // through to look for lazy compound value. It is like a field region.
1584  Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()),
1585  originalRegion);
1586 
1587  if (Result.second)
1588  Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg,
1589  Result.second);
1590  }
1591 
1592  return Result;
1593 }
1594 
1595 SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B,
1596  const ElementRegion* R) {
1597  // We do not currently model bindings of the CompoundLiteralregion.
1598  if (isa<CompoundLiteralRegion>(R->getBaseRegion()))
1599  return UnknownVal();
1600 
1601  // Check if the region has a binding.
1602  if (const Optional<SVal> &V = B.getDirectBinding(R))
1603  return *V;
1604 
1605  const MemRegion* superR = R->getSuperRegion();
1606 
1607  // Check if the region is an element region of a string literal.
1608  if (const StringRegion *StrR = dyn_cast<StringRegion>(superR)) {
1609  // FIXME: Handle loads from strings where the literal is treated as
1610  // an integer, e.g., *((unsigned int*)"hello")
1611  QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType();
1612  if (!Ctx.hasSameUnqualifiedType(T, R->getElementType()))
1613  return UnknownVal();
1614 
1615  const StringLiteral *Str = StrR->getStringLiteral();
1616  SVal Idx = R->getIndex();
1618  int64_t i = CI->getValue().getSExtValue();
1619  // Abort on string underrun. This can be possible by arbitrary
1620  // clients of getBindingForElement().
1621  if (i < 0)
1622  return UndefinedVal();
1623  int64_t length = Str->getLength();
1624  // Technically, only i == length is guaranteed to be null.
1625  // However, such overflows should be caught before reaching this point;
1626  // the only time such an access would be made is if a string literal was
1627  // used to initialize a larger array.
1628  char c = (i >= length) ? '\0' : Str->getCodeUnit(i);
1629  return svalBuilder.makeIntVal(c, T);
1630  }
1631  } else if (const VarRegion *VR = dyn_cast<VarRegion>(superR)) {
1632  // Check if the containing array is const and has an initialized value.
1633  const VarDecl *VD = VR->getDecl();
1634  // Either the array or the array element has to be const.
1635  if (VD->getType().isConstQualified() || R->getElementType().isConstQualified()) {
1636  if (const Expr *Init = VD->getInit()) {
1637  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1638  // The array index has to be known.
1639  if (auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) {
1640  int64_t i = CI->getValue().getSExtValue();
1641  // If it is known that the index is out of bounds, we can return
1642  // an undefined value.
1643  if (i < 0)
1644  return UndefinedVal();
1645 
1646  if (auto CAT = Ctx.getAsConstantArrayType(VD->getType()))
1647  if (CAT->getSize().sle(i))
1648  return UndefinedVal();
1649 
1650  // If there is a list, but no init, it must be zero.
1651  if (i >= InitList->getNumInits())
1652  return svalBuilder.makeZeroVal(R->getElementType());
1653 
1654  if (const Expr *ElemInit = InitList->getInit(i))
1655  if (Optional<SVal> V = svalBuilder.getConstantVal(ElemInit))
1656  return *V;
1657  }
1658  }
1659  }
1660  }
1661  }
1662 
1663  // Check for loads from a code text region. For such loads, just give up.
1664  if (isa<CodeTextRegion>(superR))
1665  return UnknownVal();
1666 
1667  // Handle the case where we are indexing into a larger scalar object.
1668  // For example, this handles:
1669  // int x = ...
1670  // char *y = &x;
1671  // return *y;
1672  // FIXME: This is a hack, and doesn't do anything really intelligent yet.
1673  const RegionRawOffset &O = R->getAsArrayOffset();
1674 
1675  // If we cannot reason about the offset, return an unknown value.
1676  if (!O.getRegion())
1677  return UnknownVal();
1678 
1679  if (const TypedValueRegion *baseR =
1680  dyn_cast_or_null<TypedValueRegion>(O.getRegion())) {
1681  QualType baseT = baseR->getValueType();
1682  if (baseT->isScalarType()) {
1683  QualType elemT = R->getElementType();
1684  if (elemT->isScalarType()) {
1685  if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) {
1686  if (const Optional<SVal> &V = B.getDirectBinding(superR)) {
1687  if (SymbolRef parentSym = V->getAsSymbol())
1688  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1689 
1690  if (V->isUnknownOrUndef())
1691  return *V;
1692  // Other cases: give up. We are indexing into a larger object
1693  // that has some value, but we don't know how to handle that yet.
1694  return UnknownVal();
1695  }
1696  }
1697  }
1698  }
1699  }
1700  return getBindingForFieldOrElementCommon(B, R, R->getElementType());
1701 }
1702 
1703 SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B,
1704  const FieldRegion* R) {
1705 
1706  // Check if the region has a binding.
1707  if (const Optional<SVal> &V = B.getDirectBinding(R))
1708  return *V;
1709 
1710  // Is the field declared constant and has an in-class initializer?
1711  const FieldDecl *FD = R->getDecl();
1712  QualType Ty = FD->getType();
1713  if (Ty.isConstQualified())
1714  if (const Expr *Init = FD->getInClassInitializer())
1715  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1716  return *V;
1717 
1718  // If the containing record was initialized, try to get its constant value.
1719  const MemRegion* superR = R->getSuperRegion();
1720  if (const auto *VR = dyn_cast<VarRegion>(superR)) {
1721  const VarDecl *VD = VR->getDecl();
1722  QualType RecordVarTy = VD->getType();
1723  unsigned Index = FD->getFieldIndex();
1724  // Either the record variable or the field has to be const qualified.
1725  if (RecordVarTy.isConstQualified() || Ty.isConstQualified())
1726  if (const Expr *Init = VD->getInit())
1727  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1728  if (Index < InitList->getNumInits()) {
1729  if (const Expr *FieldInit = InitList->getInit(Index))
1730  if (Optional<SVal> V = svalBuilder.getConstantVal(FieldInit))
1731  return *V;
1732  } else {
1733  return svalBuilder.makeZeroVal(Ty);
1734  }
1735  }
1736  }
1737 
1738  return getBindingForFieldOrElementCommon(B, R, Ty);
1739 }
1740 
1742 RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
1743  const MemRegion *superR,
1744  const TypedValueRegion *R,
1745  QualType Ty) {
1746 
1747  if (const Optional<SVal> &D = B.getDefaultBinding(superR)) {
1748  const SVal &val = D.getValue();
1749  if (SymbolRef parentSym = val.getAsSymbol())
1750  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1751 
1752  if (val.isZeroConstant())
1753  return svalBuilder.makeZeroVal(Ty);
1754 
1755  if (val.isUnknownOrUndef())
1756  return val;
1757 
1758  // Lazy bindings are usually handled through getExistingLazyBinding().
1759  // We should unify these two code paths at some point.
1760  if (val.getAs<nonloc::LazyCompoundVal>() ||
1761  val.getAs<nonloc::CompoundVal>())
1762  return val;
1763 
1764  llvm_unreachable("Unknown default value");
1765  }
1766 
1767  return None;
1768 }
1769 
1770 SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion,
1771  RegionBindingsRef LazyBinding) {
1772  SVal Result;
1773  if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion))
1774  Result = getBindingForElement(LazyBinding, ER);
1775  else
1776  Result = getBindingForField(LazyBinding,
1777  cast<FieldRegion>(LazyBindingRegion));
1778 
1779  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1780  // default value for /part/ of an aggregate from a default value for the
1781  // /entire/ aggregate. The most common case of this is when struct Outer
1782  // has as its first member a struct Inner, which is copied in from a stack
1783  // variable. In this case, even if the Outer's default value is symbolic, 0,
1784  // or unknown, it gets overridden by the Inner's default value of undefined.
1785  //
1786  // This is a general problem -- if the Inner is zero-initialized, the Outer
1787  // will now look zero-initialized. The proper way to solve this is with a
1788  // new version of RegionStore that tracks the extent of a binding as well
1789  // as the offset.
1790  //
1791  // This hack only takes care of the undefined case because that can very
1792  // quickly result in a warning.
1793  if (Result.isUndef())
1794  Result = UnknownVal();
1795 
1796  return Result;
1797 }
1798 
1799 SVal
1800 RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
1801  const TypedValueRegion *R,
1802  QualType Ty) {
1803 
1804  // At this point we have already checked in either getBindingForElement or
1805  // getBindingForField if 'R' has a direct binding.
1806 
1807  // Lazy binding?
1808  Store lazyBindingStore = nullptr;
1809  const SubRegion *lazyBindingRegion = nullptr;
1810  std::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R);
1811  if (lazyBindingRegion)
1812  return getLazyBinding(lazyBindingRegion,
1813  getRegionBindings(lazyBindingStore));
1814 
1815  // Record whether or not we see a symbolic index. That can completely
1816  // be out of scope of our lookup.
1817  bool hasSymbolicIndex = false;
1818 
1819  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1820  // default value for /part/ of an aggregate from a default value for the
1821  // /entire/ aggregate. The most common case of this is when struct Outer
1822  // has as its first member a struct Inner, which is copied in from a stack
1823  // variable. In this case, even if the Outer's default value is symbolic, 0,
1824  // or unknown, it gets overridden by the Inner's default value of undefined.
1825  //
1826  // This is a general problem -- if the Inner is zero-initialized, the Outer
1827  // will now look zero-initialized. The proper way to solve this is with a
1828  // new version of RegionStore that tracks the extent of a binding as well
1829  // as the offset.
1830  //
1831  // This hack only takes care of the undefined case because that can very
1832  // quickly result in a warning.
1833  bool hasPartialLazyBinding = false;
1834 
1835  const SubRegion *SR = R;
1836  while (SR) {
1837  const MemRegion *Base = SR->getSuperRegion();
1838  if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) {
1839  if (D->getAs<nonloc::LazyCompoundVal>()) {
1840  hasPartialLazyBinding = true;
1841  break;
1842  }
1843 
1844  return *D;
1845  }
1846 
1847  if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) {
1848  NonLoc index = ER->getIndex();
1849  if (!index.isConstant())
1850  hasSymbolicIndex = true;
1851  }
1852 
1853  // If our super region is a field or element itself, walk up the region
1854  // hierarchy to see if there is a default value installed in an ancestor.
1855  SR = dyn_cast<SubRegion>(Base);
1856  }
1857 
1858  if (R->hasStackNonParametersStorage()) {
1859  if (isa<ElementRegion>(R)) {
1860  // Currently we don't reason specially about Clang-style vectors. Check
1861  // if superR is a vector and if so return Unknown.
1862  if (const TypedValueRegion *typedSuperR =
1863  dyn_cast<TypedValueRegion>(R->getSuperRegion())) {
1864  if (typedSuperR->getValueType()->isVectorType())
1865  return UnknownVal();
1866  }
1867  }
1868 
1869  // FIXME: We also need to take ElementRegions with symbolic indexes into
1870  // account. This case handles both directly accessing an ElementRegion
1871  // with a symbolic offset, but also fields within an element with
1872  // a symbolic offset.
1873  if (hasSymbolicIndex)
1874  return UnknownVal();
1875 
1876  if (!hasPartialLazyBinding)
1877  return UndefinedVal();
1878  }
1879 
1880  // All other values are symbolic.
1881  return svalBuilder.getRegionValueSymbolVal(R);
1882 }
1883 
1884 SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B,
1885  const ObjCIvarRegion* R) {
1886  // Check if the region has a binding.
1887  if (const Optional<SVal> &V = B.getDirectBinding(R))
1888  return *V;
1889 
1890  const MemRegion *superR = R->getSuperRegion();
1891 
1892  // Check if the super region has a default binding.
1893  if (const Optional<SVal> &V = B.getDefaultBinding(superR)) {
1894  if (SymbolRef parentSym = V->getAsSymbol())
1895  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1896 
1897  // Other cases: give up.
1898  return UnknownVal();
1899  }
1900 
1901  return getBindingForLazySymbol(R);
1902 }
1903 
1904 SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B,
1905  const VarRegion *R) {
1906 
1907  // Check if the region has a binding.
1908  if (const Optional<SVal> &V = B.getDirectBinding(R))
1909  return *V;
1910 
1911  // Lazily derive a value for the VarRegion.
1912  const VarDecl *VD = R->getDecl();
1913  const MemSpaceRegion *MS = R->getMemorySpace();
1914 
1915  // Arguments are always symbolic.
1916  if (isa<StackArgumentsSpaceRegion>(MS))
1917  return svalBuilder.getRegionValueSymbolVal(R);
1918 
1919  // Is 'VD' declared constant? If so, retrieve the constant value.
1920  if (VD->getType().isConstQualified()) {
1921  if (const Expr *Init = VD->getInit()) {
1922  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1923  return *V;
1924 
1925  // If the variable is const qualified and has an initializer but
1926  // we couldn't evaluate initializer to a value, treat the value as
1927  // unknown.
1928  return UnknownVal();
1929  }
1930  }
1931 
1932  // This must come after the check for constants because closure-captured
1933  // constant variables may appear in UnknownSpaceRegion.
1934  if (isa<UnknownSpaceRegion>(MS))
1935  return svalBuilder.getRegionValueSymbolVal(R);
1936 
1937  if (isa<GlobalsSpaceRegion>(MS)) {
1938  QualType T = VD->getType();
1939 
1940  // Function-scoped static variables are default-initialized to 0; if they
1941  // have an initializer, it would have been processed by now.
1942  // FIXME: This is only true when we're starting analysis from main().
1943  // We're losing a lot of coverage here.
1944  if (isa<StaticGlobalSpaceRegion>(MS))
1945  return svalBuilder.makeZeroVal(T);
1946 
1947  if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) {
1948  assert(!V->getAs<nonloc::LazyCompoundVal>());
1949  return V.getValue();
1950  }
1951 
1952  return svalBuilder.getRegionValueSymbolVal(R);
1953  }
1954 
1955  return UndefinedVal();
1956 }
1957 
1958 SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
1959  // All other values are symbolic.
1960  return svalBuilder.getRegionValueSymbolVal(R);
1961 }
1962 
1963 const RegionStoreManager::SValListTy &
1964 RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) {
1965  // First, check the cache.
1966  LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData());
1967  if (I != LazyBindingsMap.end())
1968  return I->second;
1969 
1970  // If we don't have a list of values cached, start constructing it.
1971  SValListTy List;
1972 
1973  const SubRegion *LazyR = LCV.getRegion();
1974  RegionBindingsRef B = getRegionBindings(LCV.getStore());
1975 
1976  // If this region had /no/ bindings at the time, there are no interesting
1977  // values to return.
1978  const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion());
1979  if (!Cluster)
1980  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
1981 
1983  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR,
1984  /*IncludeAllDefaultBindings=*/true);
1985  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
1986  E = Bindings.end();
1987  I != E; ++I) {
1988  SVal V = I->second;
1989  if (V.isUnknownOrUndef() || V.isConstant())
1990  continue;
1991 
1992  if (Optional<nonloc::LazyCompoundVal> InnerLCV =
1994  const SValListTy &InnerList = getInterestingValues(*InnerLCV);
1995  List.insert(List.end(), InnerList.begin(), InnerList.end());
1996  continue;
1997  }
1998 
1999  List.push_back(V);
2000  }
2001 
2002  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2003 }
2004 
2005 NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B,
2006  const TypedValueRegion *R) {
2008  getExistingLazyBinding(svalBuilder, B, R, false))
2009  return *V;
2010 
2011  return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R);
2012 }
2013 
2014 static bool isRecordEmpty(const RecordDecl *RD) {
2015  if (!RD->field_empty())
2016  return false;
2017  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD))
2018  return CRD->getNumBases() == 0;
2019  return true;
2020 }
2021 
2022 SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B,
2023  const TypedValueRegion *R) {
2024  const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl();
2025  if (!RD->getDefinition() || isRecordEmpty(RD))
2026  return UnknownVal();
2027 
2028  return createLazyBinding(B, R);
2029 }
2030 
2031 SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B,
2032  const TypedValueRegion *R) {
2033  assert(Ctx.getAsConstantArrayType(R->getValueType()) &&
2034  "Only constant array types can have compound bindings.");
2035 
2036  return createLazyBinding(B, R);
2037 }
2038 
2039 bool RegionStoreManager::includedInBindings(Store store,
2040  const MemRegion *region) const {
2041  RegionBindingsRef B = getRegionBindings(store);
2042  region = region->getBaseRegion();
2043 
2044  // Quick path: if the base is the head of a cluster, the region is live.
2045  if (B.lookup(region))
2046  return true;
2047 
2048  // Slow path: if the region is the VALUE of any binding, it is live.
2049  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) {
2050  const ClusterBindings &Cluster = RI.getData();
2051  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2052  CI != CE; ++CI) {
2053  const SVal &D = CI.getData();
2054  if (const MemRegion *R = D.getAsRegion())
2055  if (R->getBaseRegion() == region)
2056  return true;
2057  }
2058  }
2059 
2060  return false;
2061 }
2062 
2063 //===----------------------------------------------------------------------===//
2064 // Binding values to regions.
2065 //===----------------------------------------------------------------------===//
2066 
2067 StoreRef RegionStoreManager::killBinding(Store ST, Loc L) {
2069  if (const MemRegion* R = LV->getRegion())
2070  return StoreRef(getRegionBindings(ST).removeBinding(R)
2071  .asImmutableMap()
2072  .getRootWithoutRetain(),
2073  *this);
2074 
2075  return StoreRef(ST, *this);
2076 }
2077 
2078 RegionBindingsRef
2079 RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) {
2080  if (L.getAs<loc::ConcreteInt>())
2081  return B;
2082 
2083  // If we get here, the location should be a region.
2084  const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion();
2085 
2086  // Check if the region is a struct region.
2087  if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) {
2088  QualType Ty = TR->getValueType();
2089  if (Ty->isArrayType())
2090  return bindArray(B, TR, V);
2091  if (Ty->isStructureOrClassType())
2092  return bindStruct(B, TR, V);
2093  if (Ty->isVectorType())
2094  return bindVector(B, TR, V);
2095  if (Ty->isUnionType())
2096  return bindAggregate(B, TR, V);
2097  }
2098 
2099  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
2100  // Binding directly to a symbolic region should be treated as binding
2101  // to element 0.
2102  QualType T = SR->getSymbol()->getType();
2103  if (T->isAnyPointerType() || T->isReferenceType())
2104  T = T->getPointeeType();
2105 
2106  R = GetElementZeroRegion(SR, T);
2107  }
2108 
2109  assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) &&
2110  "'this' pointer is not an l-value and is not assignable");
2111 
2112  // Clear out bindings that may overlap with this binding.
2113  RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R));
2114  return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V);
2115 }
2116 
2117 RegionBindingsRef
2118 RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B,
2119  const MemRegion *R,
2120  QualType T) {
2121  SVal V;
2122 
2123  if (Loc::isLocType(T))
2124  V = svalBuilder.makeNull();
2125  else if (T->isIntegralOrEnumerationType())
2126  V = svalBuilder.makeZeroVal(T);
2127  else if (T->isStructureOrClassType() || T->isArrayType()) {
2128  // Set the default value to a zero constant when it is a structure
2129  // or array. The type doesn't really matter.
2130  V = svalBuilder.makeZeroVal(Ctx.IntTy);
2131  }
2132  else {
2133  // We can't represent values of this type, but we still need to set a value
2134  // to record that the region has been initialized.
2135  // If this assertion ever fires, a new case should be added above -- we
2136  // should know how to default-initialize any value we can symbolicate.
2137  assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
2138  V = UnknownVal();
2139  }
2140 
2141  return B.addBinding(R, BindingKey::Default, V);
2142 }
2143 
2144 RegionBindingsRef
2145 RegionStoreManager::bindArray(RegionBindingsConstRef B,
2146  const TypedValueRegion* R,
2147  SVal Init) {
2148 
2149  const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType()));
2150  QualType ElementTy = AT->getElementType();
2151  Optional<uint64_t> Size;
2152 
2153  if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT))
2154  Size = CAT->getSize().getZExtValue();
2155 
2156  // Check if the init expr is a literal. If so, bind the rvalue instead.
2157  // FIXME: It's not responsibility of the Store to transform this lvalue
2158  // to rvalue. ExprEngine or maybe even CFG should do this before binding.
2160  SVal V = getBinding(B.asStore(), *MRV, R->getValueType());
2161  return bindAggregate(B, R, V);
2162  }
2163 
2164  // Handle lazy compound values.
2165  if (Init.getAs<nonloc::LazyCompoundVal>())
2166  return bindAggregate(B, R, Init);
2167 
2168  if (Init.isUnknown())
2169  return bindAggregate(B, R, UnknownVal());
2170 
2171  // Remaining case: explicit compound values.
2172  const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>();
2173  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2174  uint64_t i = 0;
2175 
2176  RegionBindingsRef NewB(B);
2177 
2178  for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) {
2179  // The init list might be shorter than the array length.
2180  if (VI == VE)
2181  break;
2182 
2183  const NonLoc &Idx = svalBuilder.makeArrayIndex(i);
2184  const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx);
2185 
2186  if (ElementTy->isStructureOrClassType())
2187  NewB = bindStruct(NewB, ER, *VI);
2188  else if (ElementTy->isArrayType())
2189  NewB = bindArray(NewB, ER, *VI);
2190  else
2191  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2192  }
2193 
2194  // If the init list is shorter than the array length (or the array has
2195  // variable length), set the array default value. Values that are already set
2196  // are not overwritten.
2197  if (!Size.hasValue() || i < Size.getValue())
2198  NewB = setImplicitDefaultValue(NewB, R, ElementTy);
2199 
2200  return NewB;
2201 }
2202 
2203 RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B,
2204  const TypedValueRegion* R,
2205  SVal V) {
2206  QualType T = R->getValueType();
2207  assert(T->isVectorType());
2208  const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs.
2209 
2210  // Handle lazy compound values and symbolic values.
2212  return bindAggregate(B, R, V);
2213 
2214  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2215  // that we are binding symbolic struct value. Kill the field values, and if
2216  // the value is symbolic go and bind it as a "default" binding.
2217  if (!V.getAs<nonloc::CompoundVal>()) {
2218  return bindAggregate(B, R, UnknownVal());
2219  }
2220 
2221  QualType ElemType = VT->getElementType();
2223  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2224  unsigned index = 0, numElements = VT->getNumElements();
2225  RegionBindingsRef NewB(B);
2226 
2227  for ( ; index != numElements ; ++index) {
2228  if (VI == VE)
2229  break;
2230 
2231  NonLoc Idx = svalBuilder.makeArrayIndex(index);
2232  const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx);
2233 
2234  if (ElemType->isArrayType())
2235  NewB = bindArray(NewB, ER, *VI);
2236  else if (ElemType->isStructureOrClassType())
2237  NewB = bindStruct(NewB, ER, *VI);
2238  else
2239  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2240  }
2241  return NewB;
2242 }
2243 
2245 RegionStoreManager::tryBindSmallStruct(RegionBindingsConstRef B,
2246  const TypedValueRegion *R,
2247  const RecordDecl *RD,
2249  FieldVector Fields;
2250 
2251  if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(RD))
2252  if (Class->getNumBases() != 0 || Class->getNumVBases() != 0)
2253  return None;
2254 
2255  for (const auto *FD : RD->fields()) {
2256  if (FD->isUnnamedBitfield())
2257  continue;
2258 
2259  // If there are too many fields, or if any of the fields are aggregates,
2260  // just use the LCV as a default binding.
2261  if (Fields.size() == SmallStructLimit)
2262  return None;
2263 
2264  QualType Ty = FD->getType();
2265  if (!(Ty->isScalarType() || Ty->isReferenceType()))
2266  return None;
2267 
2268  Fields.push_back(FD);
2269  }
2270 
2271  RegionBindingsRef NewB = B;
2272 
2273  for (FieldVector::iterator I = Fields.begin(), E = Fields.end(); I != E; ++I){
2274  const FieldRegion *SourceFR = MRMgr.getFieldRegion(*I, LCV.getRegion());
2275  SVal V = getBindingForField(getRegionBindings(LCV.getStore()), SourceFR);
2276 
2277  const FieldRegion *DestFR = MRMgr.getFieldRegion(*I, R);
2278  NewB = bind(NewB, loc::MemRegionVal(DestFR), V);
2279  }
2280 
2281  return NewB;
2282 }
2283 
2284 RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B,
2285  const TypedValueRegion* R,
2286  SVal V) {
2287  if (!Features.supportsFields())
2288  return B;
2289 
2290  QualType T = R->getValueType();
2291  assert(T->isStructureOrClassType());
2292 
2293  const RecordType* RT = T->getAs<RecordType>();
2294  const RecordDecl *RD = RT->getDecl();
2295 
2296  if (!RD->isCompleteDefinition())
2297  return B;
2298 
2299  // Handle lazy compound values and symbolic values.
2302  if (Optional<RegionBindingsRef> NewB = tryBindSmallStruct(B, R, RD, *LCV))
2303  return *NewB;
2304  return bindAggregate(B, R, V);
2305  }
2306  if (V.getAs<nonloc::SymbolVal>())
2307  return bindAggregate(B, R, V);
2308 
2309  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2310  // that we are binding symbolic struct value. Kill the field values, and if
2311  // the value is symbolic go and bind it as a "default" binding.
2312  if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>())
2313  return bindAggregate(B, R, UnknownVal());
2314 
2316  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2317 
2319  RegionBindingsRef NewB(B);
2320 
2321  for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
2322 
2323  if (VI == VE)
2324  break;
2325 
2326  // Skip any unnamed bitfields to stay in sync with the initializers.
2327  if (FI->isUnnamedBitfield())
2328  continue;
2329 
2330  QualType FTy = FI->getType();
2331  const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R);
2332 
2333  if (FTy->isArrayType())
2334  NewB = bindArray(NewB, FR, *VI);
2335  else if (FTy->isStructureOrClassType())
2336  NewB = bindStruct(NewB, FR, *VI);
2337  else
2338  NewB = bind(NewB, loc::MemRegionVal(FR), *VI);
2339  ++VI;
2340  }
2341 
2342  // There may be fewer values in the initialize list than the fields of struct.
2343  if (FI != FE) {
2344  NewB = NewB.addBinding(R, BindingKey::Default,
2345  svalBuilder.makeIntVal(0, false));
2346  }
2347 
2348  return NewB;
2349 }
2350 
2351 RegionBindingsRef
2352 RegionStoreManager::bindAggregate(RegionBindingsConstRef B,
2353  const TypedRegion *R,
2354  SVal Val) {
2355  // Remove the old bindings, using 'R' as the root of all regions
2356  // we will invalidate. Then add the new binding.
2357  return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val);
2358 }
2359 
2360 //===----------------------------------------------------------------------===//
2361 // State pruning.
2362 //===----------------------------------------------------------------------===//
2363 
2364 namespace {
2365 class removeDeadBindingsWorker :
2366  public ClusterAnalysis<removeDeadBindingsWorker> {
2368  SymbolReaper &SymReaper;
2369  const StackFrameContext *CurrentLCtx;
2370 
2371 public:
2372  removeDeadBindingsWorker(RegionStoreManager &rm,
2373  ProgramStateManager &stateMgr,
2374  RegionBindingsRef b, SymbolReaper &symReaper,
2375  const StackFrameContext *LCtx)
2376  : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b),
2377  SymReaper(symReaper), CurrentLCtx(LCtx) {}
2378 
2379  // Called by ClusterAnalysis.
2380  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C);
2381  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
2382  using ClusterAnalysis<removeDeadBindingsWorker>::VisitCluster;
2383 
2384  using ClusterAnalysis::AddToWorkList;
2385 
2386  bool AddToWorkList(const MemRegion *R);
2387 
2388  bool UpdatePostponed();
2389  void VisitBinding(SVal V);
2390 };
2391 }
2392 
2393 bool removeDeadBindingsWorker::AddToWorkList(const MemRegion *R) {
2394  const MemRegion *BaseR = R->getBaseRegion();
2395  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
2396 }
2397 
2398 void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
2399  const ClusterBindings &C) {
2400 
2401  if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) {
2402  if (SymReaper.isLive(VR))
2403  AddToWorkList(baseR, &C);
2404 
2405  return;
2406  }
2407 
2408  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) {
2409  if (SymReaper.isLive(SR->getSymbol()))
2410  AddToWorkList(SR, &C);
2411  else
2412  Postponed.push_back(SR);
2413 
2414  return;
2415  }
2416 
2417  if (isa<NonStaticGlobalSpaceRegion>(baseR)) {
2418  AddToWorkList(baseR, &C);
2419  return;
2420  }
2421 
2422  // CXXThisRegion in the current or parent location context is live.
2423  if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) {
2424  const StackArgumentsSpaceRegion *StackReg =
2425  cast<StackArgumentsSpaceRegion>(TR->getSuperRegion());
2426  const StackFrameContext *RegCtx = StackReg->getStackFrame();
2427  if (CurrentLCtx &&
2428  (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx)))
2429  AddToWorkList(TR, &C);
2430  }
2431 }
2432 
2433 void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
2434  const ClusterBindings *C) {
2435  if (!C)
2436  return;
2437 
2438  // Mark the symbol for any SymbolicRegion with live bindings as live itself.
2439  // This means we should continue to track that symbol.
2440  if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR))
2441  SymReaper.markLive(SymR->getSymbol());
2442 
2443  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) {
2444  // Element index of a binding key is live.
2445  SymReaper.markElementIndicesLive(I.getKey().getRegion());
2446 
2447  VisitBinding(I.getData());
2448  }
2449 }
2450 
2451 void removeDeadBindingsWorker::VisitBinding(SVal V) {
2452  // Is it a LazyCompoundVal? All referenced regions are live as well.
2455 
2456  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
2457 
2458  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
2459  E = Vals.end();
2460  I != E; ++I)
2461  VisitBinding(*I);
2462 
2463  return;
2464  }
2465 
2466  // If V is a region, then add it to the worklist.
2467  if (const MemRegion *R = V.getAsRegion()) {
2468  AddToWorkList(R);
2469  SymReaper.markLive(R);
2470 
2471  // All regions captured by a block are also live.
2472  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) {
2473  BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(),
2474  E = BR->referenced_vars_end();
2475  for ( ; I != E; ++I)
2476  AddToWorkList(I.getCapturedRegion());
2477  }
2478  }
2479 
2480 
2481  // Update the set of live symbols.
2482  for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end();
2483  SI!=SE; ++SI)
2484  SymReaper.markLive(*SI);
2485 }
2486 
2487 bool removeDeadBindingsWorker::UpdatePostponed() {
2488  // See if any postponed SymbolicRegions are actually live now, after
2489  // having done a scan.
2490  bool changed = false;
2491 
2493  I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) {
2494  if (const SymbolicRegion *SR = *I) {
2495  if (SymReaper.isLive(SR->getSymbol())) {
2496  changed |= AddToWorkList(SR);
2497  *I = nullptr;
2498  }
2499  }
2500  }
2501 
2502  return changed;
2503 }
2504 
2505 StoreRef RegionStoreManager::removeDeadBindings(Store store,
2506  const StackFrameContext *LCtx,
2507  SymbolReaper& SymReaper) {
2508  RegionBindingsRef B = getRegionBindings(store);
2509  removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
2510  W.GenerateClusters();
2511 
2512  // Enqueue the region roots onto the worklist.
2513  for (SymbolReaper::region_iterator I = SymReaper.region_begin(),
2514  E = SymReaper.region_end(); I != E; ++I) {
2515  W.AddToWorkList(*I);
2516  }
2517 
2518  do W.RunWorkList(); while (W.UpdatePostponed());
2519 
2520  // We have now scanned the store, marking reachable regions and symbols
2521  // as live. We now remove all the regions that are dead from the store
2522  // as well as update DSymbols with the set symbols that are now dead.
2523  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
2524  const MemRegion *Base = I.getKey();
2525 
2526  // If the cluster has been visited, we know the region has been marked.
2527  if (W.isVisited(Base))
2528  continue;
2529 
2530  // Remove the dead entry.
2531  B = B.remove(Base);
2532 
2533  if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base))
2534  SymReaper.maybeDead(SymR->getSymbol());
2535 
2536  // Mark all non-live symbols that this binding references as dead.
2537  const ClusterBindings &Cluster = I.getData();
2538  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2539  CI != CE; ++CI) {
2540  SVal X = CI.getData();
2542  for (; SI != SE; ++SI)
2543  SymReaper.maybeDead(*SI);
2544  }
2545  }
2546 
2547  return StoreRef(B.asStore(), *this);
2548 }
2549 
2550 //===----------------------------------------------------------------------===//
2551 // Utility methods.
2552 //===----------------------------------------------------------------------===//
2553 
2554 void RegionStoreManager::print(Store store, raw_ostream &OS,
2555  const char* nl, const char *sep) {
2556  RegionBindingsRef B = getRegionBindings(store);
2557  OS << "Store (direct and default bindings), "
2558  << B.asStore()
2559  << " :" << nl;
2560  B.dump(OS, nl);
2561 }
TypedValueRegion - An abstract class representing regions having a typed value.
Definition: MemRegion.h:525
A (possibly-)qualified type.
Definition: Type.h:655
MemRegion - The root abstract class for all memory regions.
Definition: MemRegion.h:94
bool isArrayType() const
Definition: Type.h:6098
static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields)
bool operator==(CanQual< T > x, CanQual< U > y)
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:30
Information about invalidation for a particular region/symbol.
Definition: MemRegion.h:1384
bool maybeDead(SymbolRef sym)
If a symbol is known to be live, marks the symbol as live.
NonLoc getIndex() const
Definition: MemRegion.h:1096
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:460
virtual QualType getValueType() const =0
StringRef P
static bool isRecordEmpty(const RecordDecl *RD)
unsigned getFieldIndex() const
Returns the index of this field within its record, as appropriate for passing to ASTRecordLayout::get...
Definition: Decl.cpp:3725
const RecordDecl * getParent() const
Returns the parent of this field declaration, which is the struct in which this field is defined...
Definition: Decl.h:2705
Represents an array type, per C99 6.7.5.2 - Array Declarators.
Definition: Type.h:2650
const MemRegion * getRegion() const
Definition: MemRegion.h:77
MemSpaceRegion - A memory region that represents a "memory space"; for example, the set of global var...
Definition: MemRegion.h:194
static Optional< nonloc::LazyCompoundVal > getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B, const SubRegion *R, bool AllowSubregionBindings)
Checks to see if store B has a lazy binding for region R.
Value representing integer constant.
Definition: SVals.h:374
A utility class that visits the reachable symbols using a custom SymbolVisitor.
Definition: ProgramState.h:900
QualType getElementType() const
Definition: Type.h:2685
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6456
const void * Store
Store - This opaque type encapsulates an immutable mapping from locations to values.
Definition: StoreRef.h:28
QualType getElementType() const
Definition: MemRegion.h:1100
bool field_empty() const
Definition: Decl.h:3772
std::unique_ptr< StoreManager > CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr)
Symbolic value.
Definition: SymExpr.h:30
CXXThisRegion - Represents the region for the implicit &#39;this&#39; parameter in a call to a C++ method...
Definition: MemRegion.h:966
const MemRegion * getSuperRegion() const
Definition: MemRegion.h:443
Represents a struct/union/class.
Definition: Decl.h:3548
llvm::ImmutableMap< BindingKey, SVal > ClusterBindings
SmallVector< const FieldDecl *, 8 > FieldVector
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:150
llvm::ImmutableList< SVal >::iterator iterator
Definition: SVals.h:462
RecordDecl * getDefinition() const
Returns the RecordDecl that actually defines this struct/union/class.
Definition: Decl.h:3754
field_range fields() const
Definition: Decl.h:3764
const FieldDecl * getDecl() const
Definition: MemRegion.h:1010
Represents a member of a struct/union/class.
Definition: Decl.h:2521
static bool canSymbolicate(QualType T)
bool isReferenceType() const
Definition: Type.h:6061
i32 captured_struct **param SharedsTy A type which contains references the shared variables *param Shareds Context with the list of shared variables from the p *TaskFunction *param Data Additional data for task generation like final * state
virtual DefinedOrUnknownSVal getExtent(SValBuilder &svalBuilder) const
getExtent - Returns the size of the region in bytes.
Definition: MemRegion.h:448
bool isIntegralOrEnumerationType() const
Determine whether this type is an integral or enumeration type.
Definition: Type.h:6370
static bool isLocType(QualType T)
Definition: SVals.h:327
BlockDataRegion - A region that represents a block instance.
Definition: MemRegion.h:668
unsigned getLength() const
Definition: Expr.h:1647
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:38
static void dump(llvm::raw_ostream &OS, StringRef FunctionName, ArrayRef< CounterExpression > Expressions, ArrayRef< CounterMappingRegion > Regions)
RegionSetTy::const_iterator region_iterator
llvm::ImmutableMap< const MemRegion *, ClusterBindings > RegionBindings
bool isUnknown() const
Definition: SVals.h:137
const LazyCompoundValData * getCVData() const
Definition: SVals.h:488
SymExpr::symbol_iterator symbol_end() const
Definition: SVals.h:205
bool isScalarType() const
Definition: Type.h:6355
QualType getValueType() const override
Definition: MemRegion.h:947
Represent a region&#39;s offset within the top level base region.
Definition: MemRegion.h:62
bool isConstant() const
Definition: SVals.cpp:218
const MemSpaceRegion * getMemorySpace() const
Definition: MemRegion.cpp:1094
SymbolRef getAsSymbol(bool IncludeBaseRegions=false) const
If this SVal wraps a symbol return that SymbolRef.
Definition: SVals.cpp:127
std::unique_ptr< StoreManager > CreateRegionStoreManager(ProgramStateManager &StMgr)
bool hasAttr() const
Definition: DeclBase.h:536
static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields)
When applied to a MemSpaceRegion, indicates the entire memory space should be invalidated.
Definition: MemRegion.h:1409
SymbolicRegion - A special, "non-concrete" region.
Definition: MemRegion.h:759
static void collectSubRegionBindings(SmallVectorImpl< BindingPair > &Bindings, SValBuilder &SVB, const ClusterBindings &Cluster, const SubRegion *Top, BindingKey TopKey, bool IncludeAllDefaultBindings)
Collects all bindings in Cluster that may refer to bindings within Top.
Expr - This represents one expression.
Definition: Expr.h:106
GlobalsFilterKind
Used to determine which global regions are automatically included in the initial worklist of a Cluste...
bool hasLocalStorage() const
Returns true if a variable with function scope is a non-static local variable.
Definition: Decl.h:1033
const FunctionProtoType * T
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6519
bool isInSystemHeader() const
Returns true if the callee is known to be from a system header.
Definition: CallEvent.h:260
uint32_t getCodeUnit(size_t i) const
Definition: Expr.h:1636
static CharUnits fromQuantity(QuantityType Quantity)
fromQuantity - Construct a CharUnits quantity from a raw integer type.
Definition: CharUnits.h:63
Represents a GCC generic vector type.
Definition: Type.h:3006
float __ovld __cnfn length(float p)
Return the length of vector p, i.e., sqrt(p.x2 + p.y 2 + ...)
bool isUnionType() const
Definition: Type.cpp:436
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:720
__UINTPTR_TYPE__ uintptr_t
An unsigned integer type with the property that any valid pointer to void can be converted to this ty...
Definition: opencl-c.h:82
llvm::ImmutableMapRef< BindingKey, SVal > ClusterBindingsRef
const StackFrameContext * getStackFrame() const
Definition: MemRegion.h:390
const VarDecl * getDecl() const
Definition: MemRegion.h:943
Optional< T > getAs() const
Convert to the specified SVal type, returning None if this SVal is not of the desired type...
Definition: SVals.h:112
virtual bool isBoundable() const
Definition: MemRegion.h:169
bool isConstQualified() const
Determine whether this type is const-qualified.
Definition: Type.h:5884
bool isVoidPointerType() const
Definition: Type.cpp:430
bool isStructureOrClassType() const
Definition: Type.cpp:422
bool scan(nonloc::LazyCompoundVal val)
llvm::BumpPtrAllocator & getAllocator()
Definition: ProgramState.h:557
Kind
const MemRegion * getAsRegion() const
Definition: SVals.cpp:151
static QualType getUnderlyingType(const SubRegion *R)
Expr * getInClassInitializer() const
Get the C++11 default member initializer for this member, or null if one has not been set...
Definition: Decl.h:2663
bool isSubRegionOf(const MemRegion *R) const override
Check if the region is a subregion of the given region.
Definition: MemRegion.cpp:133
ASTContext & getContext()
Definition: SValBuilder.h:156
SVal - This represents a symbolic expression, which can be either an L-value or an R-value...
Definition: SVals.h:76
bool isAnyPointerType() const
Definition: Type.h:6053
A class responsible for cleaning up unused symbols.
bool operator<(DeclarationName LHS, DeclarationName RHS)
Ordering on two declaration names.
region_iterator region_end() const
bool isVectorType() const
Definition: Type.h:6134
Tells that a region&#39;s contents is not changed.
Definition: MemRegion.h:1399
RegionRawOffset getAsArrayOffset() const
Compute the offset within the array. The array might also be a subobject.
Definition: MemRegion.cpp:1185
__PTRDIFF_TYPE__ ptrdiff_t
A signed integer type that is the result of subtracting two pointers.
Definition: opencl-c.h:68
bool hasSameUnqualifiedType(QualType T1, QualType T2) const
Determine whether the given types are equivalent after cvr-qualifiers have been removed.
Definition: ASTContext.h:2247
Dataflow Directional Tag Classes.
raw_ostream & operator<<(raw_ostream &Out, const CheckerBase &Checker)
Dump checker name to stream.
Definition: Checker.cpp:34
bool isZeroConstant() const
Definition: SVals.cpp:230
const void * getStore() const
Definition: SVals.cpp:166
const MemRegion * getRegion() const
Definition: MemRegion.h:1069
const Expr * getInit() const
Definition: Decl.h:1217
std::unique_ptr< DiagnosticConsumer > create(StringRef OutputFile, DiagnosticOptions *Diags, bool MergeChildRecords=false)
Returns a DiagnosticConsumer that serializes diagnostics to a bitcode file.
region_iterator region_begin() const
Represents symbolic expression.
Definition: SVals.h:347
Represents an abstract call to a function or method along a particular path.
Definition: CallEvent.h:164
specific_decl_iterator - Iterates over a subrange of declarations stored in a DeclContext, providing only those that are of type SpecificDecl (or a class derived from it).
Definition: DeclBase.h:1606
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:4072
T castAs() const
Convert to the specified SVal type, asserting that this SVal is of the desired type.
Definition: SVals.h:104
SubRegion - A region that subsets another larger region.
Definition: MemRegion.h:431
uint64_t getCharWidth() const
Return the size of the character type, in bits.
Definition: ASTContext.h:2044
RegionOffset getAsOffset() const
Compute the offset within the top level memory object.
Definition: MemRegion.cpp:1415
int64_t getOffset() const
Definition: MemRegion.h:81
std::pair< BindingKey, SVal > BindingPair
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13462
static bool isUnionField(const FieldRegion *FR)
Represents a C++ struct/union/class.
Definition: DeclCXX.h:300
const TypedValueRegion * getRegion() const
Definition: SVals.cpp:170
bool isVoidType() const
Definition: Type.h:6276
const MemRegion * getBaseRegion() const
Definition: MemRegion.cpp:1126
StringLiteral - This represents a string literal expression, e.g.
Definition: Expr.h:1566
Defines the clang::TargetInfo interface.
bool isUndef() const
Definition: SVals.h:141
StringRegion - Region associated with a StringLiteral.
Definition: MemRegion.h:794
ElementRegin is used to represent both array elements and casts.
Definition: MemRegion.h:1076
SymExpr::symbol_iterator symbol_begin() const
Definition: SVals.h:197
bool isUnion() const
Definition: Decl.h:3225
int getOptionAsInteger(StringRef Name, int DefaultVal, const ento::CheckerBase *C=nullptr, bool SearchInParents=false)
Interprets an option&#39;s string value as an integer value.
const RegionBindingsRef & RegionBindingsConstRef
QualType getType() const
Definition: Decl.h:647
#define true
Definition: stdbool.h:32
bool hasStackNonParametersStorage() const
Definition: MemRegion.cpp:1110
Represents the canonical version of C arrays with a specified constant size.
Definition: Type.h:2710
bool hasSymbolicOffset() const
Definition: MemRegion.h:79
bool isUnknownOrUndef() const
Definition: SVals.h:145
TypedRegion - An abstract class representing regions that are typed.
Definition: MemRegion.h:501
Iterator over symbols that the current symbol depends on.
Definition: SymExpr.h:69