clang  8.0.0svn
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"
23 #include "clang/Basic/TargetInfo.h"
30 #include "llvm/ADT/ImmutableMap.h"
31 #include "llvm/ADT/Optional.h"
32 #include "llvm/Support/raw_ostream.h"
33 #include <utility>
34 
35 using namespace clang;
36 using namespace ento;
37 
38 //===----------------------------------------------------------------------===//
39 // Representation of binding keys.
40 //===----------------------------------------------------------------------===//
41 
42 namespace {
43 class BindingKey {
44 public:
45  enum Kind { Default = 0x0, Direct = 0x1 };
46 private:
47  enum { Symbolic = 0x2 };
48 
49  llvm::PointerIntPair<const MemRegion *, 2> P;
50  uint64_t Data;
51 
52  /// Create a key for a binding to region \p r, which has a symbolic offset
53  /// from region \p Base.
54  explicit BindingKey(const SubRegion *r, const SubRegion *Base, Kind k)
55  : P(r, k | Symbolic), Data(reinterpret_cast<uintptr_t>(Base)) {
56  assert(r && Base && "Must have known regions.");
57  assert(getConcreteOffsetRegion() == Base && "Failed to store base region");
58  }
59 
60  /// Create a key for a binding at \p offset from base region \p r.
61  explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k)
62  : P(r, k), Data(offset) {
63  assert(r && "Must have known regions.");
64  assert(getOffset() == offset && "Failed to store offset");
65  assert((r == r->getBaseRegion() || isa<ObjCIvarRegion>(r) ||
66  isa <CXXDerivedObjectRegion>(r)) &&
67  "Not a base");
68  }
69 public:
70 
71  bool isDirect() const { return P.getInt() & Direct; }
72  bool hasSymbolicOffset() const { return P.getInt() & Symbolic; }
73 
74  const MemRegion *getRegion() const { return P.getPointer(); }
75  uint64_t getOffset() const {
76  assert(!hasSymbolicOffset());
77  return Data;
78  }
79 
80  const SubRegion *getConcreteOffsetRegion() const {
81  assert(hasSymbolicOffset());
82  return reinterpret_cast<const SubRegion *>(static_cast<uintptr_t>(Data));
83  }
84 
85  const MemRegion *getBaseRegion() const {
86  if (hasSymbolicOffset())
87  return getConcreteOffsetRegion()->getBaseRegion();
88  return getRegion()->getBaseRegion();
89  }
90 
91  void Profile(llvm::FoldingSetNodeID& ID) const {
92  ID.AddPointer(P.getOpaqueValue());
93  ID.AddInteger(Data);
94  }
95 
96  static BindingKey Make(const MemRegion *R, Kind k);
97 
98  bool operator<(const BindingKey &X) const {
99  if (P.getOpaqueValue() < X.P.getOpaqueValue())
100  return true;
101  if (P.getOpaqueValue() > X.P.getOpaqueValue())
102  return false;
103  return Data < X.Data;
104  }
105 
106  bool operator==(const BindingKey &X) const {
107  return P.getOpaqueValue() == X.P.getOpaqueValue() &&
108  Data == X.Data;
109  }
110 
111  void dump() const;
112 };
113 } // end anonymous namespace
114 
115 BindingKey BindingKey::Make(const MemRegion *R, Kind k) {
116  const RegionOffset &RO = R->getAsOffset();
117  if (RO.hasSymbolicOffset())
118  return BindingKey(cast<SubRegion>(R), cast<SubRegion>(RO.getRegion()), k);
119 
120  return BindingKey(RO.getRegion(), RO.getOffset(), k);
121 }
122 
123 namespace llvm {
124  static inline
125  raw_ostream &operator<<(raw_ostream &os, BindingKey K) {
126  os << '(' << K.getRegion();
127  if (!K.hasSymbolicOffset())
128  os << ',' << K.getOffset();
129  os << ',' << (K.isDirect() ? "direct" : "default")
130  << ')';
131  return os;
132  }
133 
134  template <typename T> struct isPodLike;
135  template <> struct isPodLike<BindingKey> {
136  static const bool value = true;
137  };
138 } // end llvm namespace
139 
140 #ifndef NDEBUG
141 LLVM_DUMP_METHOD void BindingKey::dump() const { llvm::errs() << *this; }
142 #endif
143 
144 //===----------------------------------------------------------------------===//
145 // Actual Store type.
146 //===----------------------------------------------------------------------===//
147 
148 typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings;
149 typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef;
150 typedef std::pair<BindingKey, SVal> BindingPair;
151 
152 typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings>
154 
155 namespace {
156 class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *,
157  ClusterBindings> {
158  ClusterBindings::Factory *CBFactory;
159 
160 public:
161  typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>
162  ParentTy;
163 
164  RegionBindingsRef(ClusterBindings::Factory &CBFactory,
165  const RegionBindings::TreeTy *T,
166  RegionBindings::TreeTy::Factory *F)
167  : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F),
168  CBFactory(&CBFactory) {}
169 
170  RegionBindingsRef(const ParentTy &P, ClusterBindings::Factory &CBFactory)
171  : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P),
172  CBFactory(&CBFactory) {}
173 
174  RegionBindingsRef add(key_type_ref K, data_type_ref D) const {
175  return RegionBindingsRef(static_cast<const ParentTy *>(this)->add(K, D),
176  *CBFactory);
177  }
178 
179  RegionBindingsRef remove(key_type_ref K) const {
180  return RegionBindingsRef(static_cast<const ParentTy *>(this)->remove(K),
181  *CBFactory);
182  }
183 
184  RegionBindingsRef addBinding(BindingKey K, SVal V) const;
185 
186  RegionBindingsRef addBinding(const MemRegion *R,
187  BindingKey::Kind k, SVal V) const;
188 
189  const SVal *lookup(BindingKey K) const;
190  const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const;
191  using llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>::lookup;
192 
193  RegionBindingsRef removeBinding(BindingKey K);
194 
195  RegionBindingsRef removeBinding(const MemRegion *R,
196  BindingKey::Kind k);
197 
198  RegionBindingsRef removeBinding(const MemRegion *R) {
199  return removeBinding(R, BindingKey::Direct).
200  removeBinding(R, BindingKey::Default);
201  }
202 
203  Optional<SVal> getDirectBinding(const MemRegion *R) const;
204 
205  /// getDefaultBinding - Returns an SVal* representing an optional default
206  /// binding associated with a region and its subregions.
207  Optional<SVal> getDefaultBinding(const MemRegion *R) const;
208 
209  /// Return the internal tree as a Store.
210  Store asStore() const {
211  return asImmutableMap().getRootWithoutRetain();
212  }
213 
214  void dump(raw_ostream &OS, const char *nl) const {
215  for (iterator I = begin(), E = end(); I != E; ++I) {
216  const ClusterBindings &Cluster = I.getData();
217  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
218  CI != CE; ++CI) {
219  OS << ' ' << CI.getKey() << " : " << CI.getData() << nl;
220  }
221  OS << nl;
222  }
223  }
224 
225  LLVM_DUMP_METHOD void dump() const { dump(llvm::errs(), "\n"); }
226 };
227 } // end anonymous namespace
228 
229 typedef const RegionBindingsRef& RegionBindingsConstRef;
230 
231 Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const {
232  return Optional<SVal>::create(lookup(R, BindingKey::Direct));
233 }
234 
235 Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const {
236  return Optional<SVal>::create(lookup(R, BindingKey::Default));
237 }
238 
239 RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const {
240  const MemRegion *Base = K.getBaseRegion();
241 
242  const ClusterBindings *ExistingCluster = lookup(Base);
243  ClusterBindings Cluster =
244  (ExistingCluster ? *ExistingCluster : CBFactory->getEmptyMap());
245 
246  ClusterBindings NewCluster = CBFactory->add(Cluster, K, V);
247  return add(Base, NewCluster);
248 }
249 
250 
251 RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R,
252  BindingKey::Kind k,
253  SVal V) const {
254  return addBinding(BindingKey::Make(R, k), V);
255 }
256 
257 const SVal *RegionBindingsRef::lookup(BindingKey K) const {
258  const ClusterBindings *Cluster = lookup(K.getBaseRegion());
259  if (!Cluster)
260  return nullptr;
261  return Cluster->lookup(K);
262 }
263 
264 const SVal *RegionBindingsRef::lookup(const MemRegion *R,
265  BindingKey::Kind k) const {
266  return lookup(BindingKey::Make(R, k));
267 }
268 
269 RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) {
270  const MemRegion *Base = K.getBaseRegion();
271  const ClusterBindings *Cluster = lookup(Base);
272  if (!Cluster)
273  return *this;
274 
275  ClusterBindings NewCluster = CBFactory->remove(*Cluster, K);
276  if (NewCluster.isEmpty())
277  return remove(Base);
278  return add(Base, NewCluster);
279 }
280 
281 RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R,
282  BindingKey::Kind k){
283  return removeBinding(BindingKey::Make(R, k));
284 }
285 
286 //===----------------------------------------------------------------------===//
287 // Fine-grained control of RegionStoreManager.
288 //===----------------------------------------------------------------------===//
289 
290 namespace {
291 struct minimal_features_tag {};
292 struct maximal_features_tag {};
293 
294 class RegionStoreFeatures {
295  bool SupportsFields;
296 public:
297  RegionStoreFeatures(minimal_features_tag) :
298  SupportsFields(false) {}
299 
300  RegionStoreFeatures(maximal_features_tag) :
301  SupportsFields(true) {}
302 
303  void enableFields(bool t) { SupportsFields = t; }
304 
305  bool supportsFields() const { return SupportsFields; }
306 };
307 }
308 
309 //===----------------------------------------------------------------------===//
310 // Main RegionStore logic.
311 //===----------------------------------------------------------------------===//
312 
313 namespace {
314 class InvalidateRegionsWorker;
315 
316 class RegionStoreManager : public StoreManager {
317 public:
318  const RegionStoreFeatures Features;
319 
320  RegionBindings::Factory RBFactory;
321  mutable ClusterBindings::Factory CBFactory;
322 
323  typedef std::vector<SVal> SValListTy;
324 private:
325  typedef llvm::DenseMap<const LazyCompoundValData *,
326  SValListTy> LazyBindingsMapTy;
327  LazyBindingsMapTy LazyBindingsMap;
328 
329  /// The largest number of fields a struct can have and still be
330  /// considered "small".
331  ///
332  /// This is currently used to decide whether or not it is worth "forcing" a
333  /// LazyCompoundVal on bind.
334  ///
335  /// This is controlled by 'region-store-small-struct-limit' option.
336  /// To disable all small-struct-dependent behavior, set the option to "0".
337  unsigned SmallStructLimit;
338 
339  /// A helper used to populate the work list with the given set of
340  /// regions.
341  void populateWorkList(InvalidateRegionsWorker &W,
342  ArrayRef<SVal> Values,
343  InvalidatedRegions *TopLevelRegions);
344 
345 public:
346  RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f)
347  : StoreManager(mgr), Features(f),
348  RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()),
349  SmallStructLimit(0) {
350  if (SubEngine *Eng = StateMgr.getOwningEngine()) {
351  AnalyzerOptions &Options = Eng->getAnalysisManager().options;
352  SmallStructLimit =
353  Options.getOptionAsInteger("region-store-small-struct-limit", 2);
354  }
355  }
356 
357 
358  /// setImplicitDefaultValue - Set the default binding for the provided
359  /// MemRegion to the value implicitly defined for compound literals when
360  /// the value is not specified.
361  RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B,
362  const MemRegion *R, QualType T);
363 
364  /// ArrayToPointer - Emulates the "decay" of an array to a pointer
365  /// type. 'Array' represents the lvalue of the array being decayed
366  /// to a pointer, and the returned SVal represents the decayed
367  /// version of that lvalue (i.e., a pointer to the first element of
368  /// the array). This is called by ExprEngine when evaluating
369  /// casts from arrays to pointers.
370  SVal ArrayToPointer(Loc Array, QualType ElementTy) override;
371 
372  StoreRef getInitialStore(const LocationContext *InitLoc) override {
373  return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this);
374  }
375 
376  //===-------------------------------------------------------------------===//
377  // Binding values to regions.
378  //===-------------------------------------------------------------------===//
379  RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K,
380  const Expr *Ex,
381  unsigned Count,
382  const LocationContext *LCtx,
383  RegionBindingsRef B,
384  InvalidatedRegions *Invalidated);
385 
386  StoreRef invalidateRegions(Store store,
387  ArrayRef<SVal> Values,
388  const Expr *E, unsigned Count,
389  const LocationContext *LCtx,
390  const CallEvent *Call,
391  InvalidatedSymbols &IS,
392  RegionAndSymbolInvalidationTraits &ITraits,
393  InvalidatedRegions *Invalidated,
394  InvalidatedRegions *InvalidatedTopLevel) override;
395 
396  bool scanReachableSymbols(Store S, const MemRegion *R,
397  ScanReachableSymbols &Callbacks) override;
398 
399  RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B,
400  const SubRegion *R);
401 
402 public: // Part of public interface to class.
403 
404  StoreRef Bind(Store store, Loc LV, SVal V) override {
405  return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this);
406  }
407 
408  RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V);
409 
410  // BindDefaultInitial is only used to initialize a region with
411  // a default value.
412  StoreRef BindDefaultInitial(Store store, const MemRegion *R,
413  SVal V) override {
414  RegionBindingsRef B = getRegionBindings(store);
415  // Use other APIs when you have to wipe the region that was initialized
416  // earlier.
417  assert(!(B.getDefaultBinding(R) || B.getDirectBinding(R)) &&
418  "Double initialization!");
419  B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
420  return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
421  }
422 
423  // BindDefaultZero is used for zeroing constructors that may accidentally
424  // overwrite existing bindings.
425  StoreRef BindDefaultZero(Store store, const MemRegion *R) override {
426  // FIXME: The offsets of empty bases can be tricky because of
427  // of the so called "empty base class optimization".
428  // If a base class has been optimized out
429  // we should not try to create a binding, otherwise we should.
430  // Unfortunately, at the moment ASTRecordLayout doesn't expose
431  // the actual sizes of the empty bases
432  // and trying to infer them from offsets/alignments
433  // seems to be error-prone and non-trivial because of the trailing padding.
434  // As a temporary mitigation we don't create bindings for empty bases.
435  if (const auto *BR = dyn_cast<CXXBaseObjectRegion>(R))
436  if (BR->getDecl()->isEmpty())
437  return StoreRef(store, *this);
438 
439  RegionBindingsRef B = getRegionBindings(store);
440  SVal V = svalBuilder.makeZeroVal(Ctx.CharTy);
441  B = removeSubRegionBindings(B, cast<SubRegion>(R));
442  B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
443  return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
444  }
445 
446  /// Attempt to extract the fields of \p LCV and bind them to the struct region
447  /// \p R.
448  ///
449  /// This path is used when it seems advantageous to "force" loading the values
450  /// within a LazyCompoundVal to bind memberwise to the struct region, rather
451  /// than using a Default binding at the base of the entire region. This is a
452  /// heuristic attempting to avoid building long chains of LazyCompoundVals.
453  ///
454  /// \returns The updated store bindings, or \c None if binding non-lazily
455  /// would be too expensive.
456  Optional<RegionBindingsRef> tryBindSmallStruct(RegionBindingsConstRef B,
457  const TypedValueRegion *R,
458  const RecordDecl *RD,
459  nonloc::LazyCompoundVal LCV);
460 
461  /// BindStruct - Bind a compound value to a structure.
462  RegionBindingsRef bindStruct(RegionBindingsConstRef B,
463  const TypedValueRegion* R, SVal V);
464 
465  /// BindVector - Bind a compound value to a vector.
466  RegionBindingsRef bindVector(RegionBindingsConstRef B,
467  const TypedValueRegion* R, SVal V);
468 
469  RegionBindingsRef bindArray(RegionBindingsConstRef B,
470  const TypedValueRegion* R,
471  SVal V);
472 
473  /// Clears out all bindings in the given region and assigns a new value
474  /// as a Default binding.
475  RegionBindingsRef bindAggregate(RegionBindingsConstRef B,
476  const TypedRegion *R,
477  SVal DefaultVal);
478 
479  /// Create a new store with the specified binding removed.
480  /// \param ST the original store, that is the basis for the new store.
481  /// \param L the location whose binding should be removed.
482  StoreRef killBinding(Store ST, Loc L) override;
483 
484  void incrementReferenceCount(Store store) override {
485  getRegionBindings(store).manualRetain();
486  }
487 
488  /// If the StoreManager supports it, decrement the reference count of
489  /// the specified Store object. If the reference count hits 0, the memory
490  /// associated with the object is recycled.
491  void decrementReferenceCount(Store store) override {
492  getRegionBindings(store).manualRelease();
493  }
494 
495  bool includedInBindings(Store store, const MemRegion *region) const override;
496 
497  /// Return the value bound to specified location in a given state.
498  ///
499  /// The high level logic for this method is this:
500  /// getBinding (L)
501  /// if L has binding
502  /// return L's binding
503  /// else if L is in killset
504  /// return unknown
505  /// else
506  /// if L is on stack or heap
507  /// return undefined
508  /// else
509  /// return symbolic
510  SVal getBinding(Store S, Loc L, QualType T) override {
511  return getBinding(getRegionBindings(S), L, T);
512  }
513 
514  Optional<SVal> getDefaultBinding(Store S, const MemRegion *R) override {
515  RegionBindingsRef B = getRegionBindings(S);
516  // Default bindings are always applied over a base region so look up the
517  // base region's default binding, otherwise the lookup will fail when R
518  // is at an offset from R->getBaseRegion().
519  return B.getDefaultBinding(R->getBaseRegion());
520  }
521 
522  SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType());
523 
524  SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R);
525 
526  SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R);
527 
528  SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R);
529 
530  SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R);
531 
532  SVal getBindingForLazySymbol(const TypedValueRegion *R);
533 
534  SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
535  const TypedValueRegion *R,
536  QualType Ty);
537 
538  SVal getLazyBinding(const SubRegion *LazyBindingRegion,
539  RegionBindingsRef LazyBinding);
540 
541  /// Get bindings for the values in a struct and return a CompoundVal, used
542  /// when doing struct copy:
543  /// struct s x, y;
544  /// x = y;
545  /// y's value is retrieved by this method.
546  SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R);
547  SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R);
548  NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R);
549 
550  /// Used to lazily generate derived symbols for bindings that are defined
551  /// implicitly by default bindings in a super region.
552  ///
553  /// Note that callers may need to specially handle LazyCompoundVals, which
554  /// are returned as is in case the caller needs to treat them differently.
555  Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
556  const MemRegion *superR,
557  const TypedValueRegion *R,
558  QualType Ty);
559 
560  /// Get the state and region whose binding this region \p R corresponds to.
561  ///
562  /// If there is no lazy binding for \p R, the returned value will have a null
563  /// \c second. Note that a null pointer can represents a valid Store.
564  std::pair<Store, const SubRegion *>
565  findLazyBinding(RegionBindingsConstRef B, const SubRegion *R,
566  const SubRegion *originalRegion);
567 
568  /// Returns the cached set of interesting SVals contained within a lazy
569  /// binding.
570  ///
571  /// The precise value of "interesting" is determined for the purposes of
572  /// RegionStore's internal analysis. It must always contain all regions and
573  /// symbols, but may omit constants and other kinds of SVal.
574  const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV);
575 
576  //===------------------------------------------------------------------===//
577  // State pruning.
578  //===------------------------------------------------------------------===//
579 
580  /// removeDeadBindings - Scans the RegionStore of 'state' for dead values.
581  /// It returns a new Store with these values removed.
582  StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
583  SymbolReaper& SymReaper) override;
584 
585  //===------------------------------------------------------------------===//
586  // Region "extents".
587  //===------------------------------------------------------------------===//
588 
589  // FIXME: This method will soon be eliminated; see the note in Store.h.
590  DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state,
591  const MemRegion* R,
592  QualType EleTy) override;
593 
594  //===------------------------------------------------------------------===//
595  // Utility methods.
596  //===------------------------------------------------------------------===//
597 
598  RegionBindingsRef getRegionBindings(Store store) const {
599  return RegionBindingsRef(CBFactory,
600  static_cast<const RegionBindings::TreeTy*>(store),
601  RBFactory.getTreeFactory());
602  }
603 
604  void print(Store store, raw_ostream &Out, const char* nl,
605  const char *sep) override;
606 
607  void iterBindings(Store store, BindingsHandler& f) override {
608  RegionBindingsRef B = getRegionBindings(store);
609  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
610  const ClusterBindings &Cluster = I.getData();
611  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
612  CI != CE; ++CI) {
613  const BindingKey &K = CI.getKey();
614  if (!K.isDirect())
615  continue;
616  if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) {
617  // FIXME: Possibly incorporate the offset?
618  if (!f.HandleBinding(*this, store, R, CI.getData()))
619  return;
620  }
621  }
622  }
623  }
624 };
625 
626 } // end anonymous namespace
627 
628 //===----------------------------------------------------------------------===//
629 // RegionStore creation.
630 //===----------------------------------------------------------------------===//
631 
632 std::unique_ptr<StoreManager>
634  RegionStoreFeatures F = maximal_features_tag();
635  return llvm::make_unique<RegionStoreManager>(StMgr, F);
636 }
637 
638 std::unique_ptr<StoreManager>
640  RegionStoreFeatures F = minimal_features_tag();
641  F.enableFields(true);
642  return llvm::make_unique<RegionStoreManager>(StMgr, F);
643 }
644 
645 
646 //===----------------------------------------------------------------------===//
647 // Region Cluster analysis.
648 //===----------------------------------------------------------------------===//
649 
650 namespace {
651 /// Used to determine which global regions are automatically included in the
652 /// initial worklist of a ClusterAnalysis.
654  /// Don't include any global regions.
655  GFK_None,
656  /// Only include system globals.
657  GFK_SystemOnly,
658  /// Include all global regions.
659  GFK_All
660 };
661 
662 template <typename DERIVED>
663 class ClusterAnalysis {
664 protected:
665  typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap;
666  typedef const MemRegion * WorkListElement;
667  typedef SmallVector<WorkListElement, 10> WorkList;
668 
669  llvm::SmallPtrSet<const ClusterBindings *, 16> Visited;
670 
671  WorkList WL;
672 
673  RegionStoreManager &RM;
674  ASTContext &Ctx;
675  SValBuilder &svalBuilder;
676 
677  RegionBindingsRef B;
678 
679 
680 protected:
681  const ClusterBindings *getCluster(const MemRegion *R) {
682  return B.lookup(R);
683  }
684 
685  /// Returns true if all clusters in the given memspace should be initially
686  /// included in the cluster analysis. Subclasses may provide their
687  /// own implementation.
688  bool includeEntireMemorySpace(const MemRegion *Base) {
689  return false;
690  }
691 
692 public:
693  ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr,
694  RegionBindingsRef b)
695  : RM(rm), Ctx(StateMgr.getContext()),
696  svalBuilder(StateMgr.getSValBuilder()), B(std::move(b)) {}
697 
698  RegionBindingsRef getRegionBindings() const { return B; }
699 
700  bool isVisited(const MemRegion *R) {
701  return Visited.count(getCluster(R));
702  }
703 
704  void GenerateClusters() {
705  // Scan the entire set of bindings and record the region clusters.
706  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end();
707  RI != RE; ++RI){
708  const MemRegion *Base = RI.getKey();
709 
710  const ClusterBindings &Cluster = RI.getData();
711  assert(!Cluster.isEmpty() && "Empty clusters should be removed");
712  static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster);
713 
714  // If the base's memspace should be entirely invalidated, add the cluster
715  // to the workspace up front.
716  if (static_cast<DERIVED*>(this)->includeEntireMemorySpace(Base))
717  AddToWorkList(WorkListElement(Base), &Cluster);
718  }
719  }
720 
721  bool AddToWorkList(WorkListElement E, const ClusterBindings *C) {
722  if (C && !Visited.insert(C).second)
723  return false;
724  WL.push_back(E);
725  return true;
726  }
727 
728  bool AddToWorkList(const MemRegion *R) {
729  return static_cast<DERIVED*>(this)->AddToWorkList(R);
730  }
731 
732  void RunWorkList() {
733  while (!WL.empty()) {
734  WorkListElement E = WL.pop_back_val();
735  const MemRegion *BaseR = E;
736 
737  static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR));
738  }
739  }
740 
741  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {}
742  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {}
743 
744  void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C,
745  bool Flag) {
746  static_cast<DERIVED*>(this)->VisitCluster(BaseR, C);
747  }
748 };
749 }
750 
751 //===----------------------------------------------------------------------===//
752 // Binding invalidation.
753 //===----------------------------------------------------------------------===//
754 
755 bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R,
756  ScanReachableSymbols &Callbacks) {
757  assert(R == R->getBaseRegion() && "Should only be called for base regions");
758  RegionBindingsRef B = getRegionBindings(S);
759  const ClusterBindings *Cluster = B.lookup(R);
760 
761  if (!Cluster)
762  return true;
763 
764  for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end();
765  RI != RE; ++RI) {
766  if (!Callbacks.scan(RI.getData()))
767  return false;
768  }
769 
770  return true;
771 }
772 
773 static inline bool isUnionField(const FieldRegion *FR) {
774  return FR->getDecl()->getParent()->isUnion();
775 }
776 
778 
779 static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) {
780  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
781 
782  const MemRegion *Base = K.getConcreteOffsetRegion();
783  const MemRegion *R = K.getRegion();
784 
785  while (R != Base) {
786  if (const FieldRegion *FR = dyn_cast<FieldRegion>(R))
787  if (!isUnionField(FR))
788  Fields.push_back(FR->getDecl());
789 
790  R = cast<SubRegion>(R)->getSuperRegion();
791  }
792 }
793 
794 static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) {
795  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
796 
797  if (Fields.empty())
798  return true;
799 
800  FieldVector FieldsInBindingKey;
801  getSymbolicOffsetFields(K, FieldsInBindingKey);
802 
803  ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size();
804  if (Delta >= 0)
805  return std::equal(FieldsInBindingKey.begin() + Delta,
806  FieldsInBindingKey.end(),
807  Fields.begin());
808  else
809  return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(),
810  Fields.begin() - Delta);
811 }
812 
813 /// Collects all bindings in \p Cluster that may refer to bindings within
814 /// \p Top.
815 ///
816 /// Each binding is a pair whose \c first is the key (a BindingKey) and whose
817 /// \c second is the value (an SVal).
818 ///
819 /// The \p IncludeAllDefaultBindings parameter specifies whether to include
820 /// default bindings that may extend beyond \p Top itself, e.g. if \p Top is
821 /// an aggregate within a larger aggregate with a default binding.
822 static void
824  SValBuilder &SVB, const ClusterBindings &Cluster,
825  const SubRegion *Top, BindingKey TopKey,
826  bool IncludeAllDefaultBindings) {
827  FieldVector FieldsInSymbolicSubregions;
828  if (TopKey.hasSymbolicOffset()) {
829  getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions);
830  Top = TopKey.getConcreteOffsetRegion();
831  TopKey = BindingKey::Make(Top, BindingKey::Default);
832  }
833 
834  // Find the length (in bits) of the region being invalidated.
835  uint64_t Length = UINT64_MAX;
836  SVal Extent = Top->getExtent(SVB);
837  if (Optional<nonloc::ConcreteInt> ExtentCI =
838  Extent.getAs<nonloc::ConcreteInt>()) {
839  const llvm::APSInt &ExtentInt = ExtentCI->getValue();
840  assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned());
841  // Extents are in bytes but region offsets are in bits. Be careful!
842  Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth();
843  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) {
844  if (FR->getDecl()->isBitField())
845  Length = FR->getDecl()->getBitWidthValue(SVB.getContext());
846  }
847 
848  for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end();
849  I != E; ++I) {
850  BindingKey NextKey = I.getKey();
851  if (NextKey.getRegion() == TopKey.getRegion()) {
852  // FIXME: This doesn't catch the case where we're really invalidating a
853  // region with a symbolic offset. Example:
854  // R: points[i].y
855  // Next: points[0].x
856 
857  if (NextKey.getOffset() > TopKey.getOffset() &&
858  NextKey.getOffset() - TopKey.getOffset() < Length) {
859  // Case 1: The next binding is inside the region we're invalidating.
860  // Include it.
861  Bindings.push_back(*I);
862 
863  } else if (NextKey.getOffset() == TopKey.getOffset()) {
864  // Case 2: The next binding is at the same offset as the region we're
865  // invalidating. In this case, we need to leave default bindings alone,
866  // since they may be providing a default value for a regions beyond what
867  // we're invalidating.
868  // FIXME: This is probably incorrect; consider invalidating an outer
869  // struct whose first field is bound to a LazyCompoundVal.
870  if (IncludeAllDefaultBindings || NextKey.isDirect())
871  Bindings.push_back(*I);
872  }
873 
874  } else if (NextKey.hasSymbolicOffset()) {
875  const MemRegion *Base = NextKey.getConcreteOffsetRegion();
876  if (Top->isSubRegionOf(Base) && Top != Base) {
877  // Case 3: The next key is symbolic and we just changed something within
878  // its concrete region. We don't know if the binding is still valid, so
879  // we'll be conservative and include it.
880  if (IncludeAllDefaultBindings || NextKey.isDirect())
881  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
882  Bindings.push_back(*I);
883  } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) {
884  // Case 4: The next key is symbolic, but we changed a known
885  // super-region. In this case the binding is certainly included.
886  if (BaseSR->isSubRegionOf(Top))
887  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
888  Bindings.push_back(*I);
889  }
890  }
891  }
892 }
893 
894 static void
896  SValBuilder &SVB, const ClusterBindings &Cluster,
897  const SubRegion *Top, bool IncludeAllDefaultBindings) {
898  collectSubRegionBindings(Bindings, SVB, Cluster, Top,
900  IncludeAllDefaultBindings);
901 }
902 
903 RegionBindingsRef
904 RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B,
905  const SubRegion *Top) {
906  BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default);
907  const MemRegion *ClusterHead = TopKey.getBaseRegion();
908 
909  if (Top == ClusterHead) {
910  // We can remove an entire cluster's bindings all in one go.
911  return B.remove(Top);
912  }
913 
914  const ClusterBindings *Cluster = B.lookup(ClusterHead);
915  if (!Cluster) {
916  // If we're invalidating a region with a symbolic offset, we need to make
917  // sure we don't treat the base region as uninitialized anymore.
918  if (TopKey.hasSymbolicOffset()) {
919  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
920  return B.addBinding(Concrete, BindingKey::Default, UnknownVal());
921  }
922  return B;
923  }
924 
926  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey,
927  /*IncludeAllDefaultBindings=*/false);
928 
929  ClusterBindingsRef Result(*Cluster, CBFactory);
930  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
931  E = Bindings.end();
932  I != E; ++I)
933  Result = Result.remove(I->first);
934 
935  // If we're invalidating a region with a symbolic offset, we need to make sure
936  // we don't treat the base region as uninitialized anymore.
937  // FIXME: This isn't very precise; see the example in
938  // collectSubRegionBindings.
939  if (TopKey.hasSymbolicOffset()) {
940  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
941  Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default),
942  UnknownVal());
943  }
944 
945  if (Result.isEmpty())
946  return B.remove(ClusterHead);
947  return B.add(ClusterHead, Result.asImmutableMap());
948 }
949 
950 namespace {
951 class InvalidateRegionsWorker : public ClusterAnalysis<InvalidateRegionsWorker>
952 {
953  const Expr *Ex;
954  unsigned Count;
955  const LocationContext *LCtx;
956  InvalidatedSymbols &IS;
957  RegionAndSymbolInvalidationTraits &ITraits;
959  GlobalsFilterKind GlobalsFilter;
960 public:
961  InvalidateRegionsWorker(RegionStoreManager &rm,
962  ProgramStateManager &stateMgr,
963  RegionBindingsRef b,
964  const Expr *ex, unsigned count,
965  const LocationContext *lctx,
966  InvalidatedSymbols &is,
967  RegionAndSymbolInvalidationTraits &ITraitsIn,
969  GlobalsFilterKind GFK)
970  : ClusterAnalysis<InvalidateRegionsWorker>(rm, stateMgr, b),
971  Ex(ex), Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r),
972  GlobalsFilter(GFK) {}
973 
974  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
975  void VisitBinding(SVal V);
976 
977  using ClusterAnalysis::AddToWorkList;
978 
979  bool AddToWorkList(const MemRegion *R);
980 
981  /// Returns true if all clusters in the memory space for \p Base should be
982  /// be invalidated.
983  bool includeEntireMemorySpace(const MemRegion *Base);
984 
985  /// Returns true if the memory space of the given region is one of the global
986  /// regions specially included at the start of invalidation.
987  bool isInitiallyIncludedGlobalRegion(const MemRegion *R);
988 };
989 }
990 
991 bool InvalidateRegionsWorker::AddToWorkList(const MemRegion *R) {
992  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
994  const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion();
995  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
996 }
997 
998 void InvalidateRegionsWorker::VisitBinding(SVal V) {
999  // A symbol? Mark it touched by the invalidation.
1000  if (SymbolRef Sym = V.getAsSymbol())
1001  IS.insert(Sym);
1002 
1003  if (const MemRegion *R = V.getAsRegion()) {
1004  AddToWorkList(R);
1005  return;
1006  }
1007 
1008  // Is it a LazyCompoundVal? All references get invalidated as well.
1010  V.getAs<nonloc::LazyCompoundVal>()) {
1011 
1012  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
1013 
1014  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
1015  E = Vals.end();
1016  I != E; ++I)
1017  VisitBinding(*I);
1018 
1019  return;
1020  }
1021 }
1022 
1023 void InvalidateRegionsWorker::VisitCluster(const MemRegion *baseR,
1024  const ClusterBindings *C) {
1025 
1026  bool PreserveRegionsContents =
1027  ITraits.hasTrait(baseR,
1029 
1030  if (C) {
1031  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I)
1032  VisitBinding(I.getData());
1033 
1034  // Invalidate regions contents.
1035  if (!PreserveRegionsContents)
1036  B = B.remove(baseR);
1037  }
1038 
1039  if (const auto *TO = dyn_cast<TypedValueRegion>(baseR)) {
1040  if (const auto *RD = TO->getValueType()->getAsCXXRecordDecl()) {
1041 
1042  // Lambdas can affect all static local variables without explicitly
1043  // capturing those.
1044  // We invalidate all static locals referenced inside the lambda body.
1045  if (RD->isLambda() && RD->getLambdaCallOperator()->getBody()) {
1046  using namespace ast_matchers;
1047 
1048  const char *DeclBind = "DeclBind";
1050  to(varDecl(hasStaticStorageDuration()).bind(DeclBind)))));
1051  auto Matches =
1052  match(RefToStatic, *RD->getLambdaCallOperator()->getBody(),
1053  RD->getASTContext());
1054 
1055  for (BoundNodes &Match : Matches) {
1056  auto *VD = Match.getNodeAs<VarDecl>(DeclBind);
1057  const VarRegion *ToInvalidate =
1058  RM.getRegionManager().getVarRegion(VD, LCtx);
1059  AddToWorkList(ToInvalidate);
1060  }
1061  }
1062  }
1063  }
1064 
1065  // BlockDataRegion? If so, invalidate captured variables that are passed
1066  // by reference.
1067  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) {
1068  for (BlockDataRegion::referenced_vars_iterator
1069  BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ;
1070  BI != BE; ++BI) {
1071  const VarRegion *VR = BI.getCapturedRegion();
1072  const VarDecl *VD = VR->getDecl();
1073  if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage()) {
1074  AddToWorkList(VR);
1075  }
1076  else if (Loc::isLocType(VR->getValueType())) {
1077  // Map the current bindings to a Store to retrieve the value
1078  // of the binding. If that binding itself is a region, we should
1079  // invalidate that region. This is because a block may capture
1080  // a pointer value, but the thing pointed by that pointer may
1081  // get invalidated.
1082  SVal V = RM.getBinding(B, loc::MemRegionVal(VR));
1083  if (Optional<Loc> L = V.getAs<Loc>()) {
1084  if (const MemRegion *LR = L->getAsRegion())
1085  AddToWorkList(LR);
1086  }
1087  }
1088  }
1089  return;
1090  }
1091 
1092  // Symbolic region?
1093  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR))
1094  IS.insert(SR->getSymbol());
1095 
1096  // Nothing else should be done in the case when we preserve regions context.
1097  if (PreserveRegionsContents)
1098  return;
1099 
1100  // Otherwise, we have a normal data region. Record that we touched the region.
1101  if (Regions)
1102  Regions->push_back(baseR);
1103 
1104  if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) {
1105  // Invalidate the region by setting its default value to
1106  // conjured symbol. The type of the symbol is irrelevant.
1107  DefinedOrUnknownSVal V =
1108  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
1109  B = B.addBinding(baseR, BindingKey::Default, V);
1110  return;
1111  }
1112 
1113  if (!baseR->isBoundable())
1114  return;
1115 
1116  const TypedValueRegion *TR = cast<TypedValueRegion>(baseR);
1117  QualType T = TR->getValueType();
1118 
1119  if (isInitiallyIncludedGlobalRegion(baseR)) {
1120  // If the region is a global and we are invalidating all globals,
1121  // erasing the entry is good enough. This causes all globals to be lazily
1122  // symbolicated from the same base symbol.
1123  return;
1124  }
1125 
1126  if (T->isRecordType()) {
1127  // Invalidate the region by setting its default value to
1128  // conjured symbol. The type of the symbol is irrelevant.
1129  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1130  Ctx.IntTy, Count);
1131  B = B.addBinding(baseR, BindingKey::Default, V);
1132  return;
1133  }
1134 
1135  if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
1136  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1137  baseR,
1139 
1140  if (doNotInvalidateSuperRegion) {
1141  // We are not doing blank invalidation of the whole array region so we
1142  // have to manually invalidate each elements.
1143  Optional<uint64_t> NumElements;
1144 
1145  // Compute lower and upper offsets for region within array.
1146  if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT))
1147  NumElements = CAT->getSize().getZExtValue();
1148  if (!NumElements) // We are not dealing with a constant size array
1149  goto conjure_default;
1150  QualType ElementTy = AT->getElementType();
1151  uint64_t ElemSize = Ctx.getTypeSize(ElementTy);
1152  const RegionOffset &RO = baseR->getAsOffset();
1153  const MemRegion *SuperR = baseR->getBaseRegion();
1154  if (RO.hasSymbolicOffset()) {
1155  // If base region has a symbolic offset,
1156  // we revert to invalidating the super region.
1157  if (SuperR)
1158  AddToWorkList(SuperR);
1159  goto conjure_default;
1160  }
1161 
1162  uint64_t LowerOffset = RO.getOffset();
1163  uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize;
1164  bool UpperOverflow = UpperOffset < LowerOffset;
1165 
1166  // Invalidate regions which are within array boundaries,
1167  // or have a symbolic offset.
1168  if (!SuperR)
1169  goto conjure_default;
1170 
1171  const ClusterBindings *C = B.lookup(SuperR);
1172  if (!C)
1173  goto conjure_default;
1174 
1175  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E;
1176  ++I) {
1177  const BindingKey &BK = I.getKey();
1178  Optional<uint64_t> ROffset =
1179  BK.hasSymbolicOffset() ? Optional<uint64_t>() : BK.getOffset();
1180 
1181  // Check offset is not symbolic and within array's boundaries.
1182  // Handles arrays of 0 elements and of 0-sized elements as well.
1183  if (!ROffset ||
1184  ((*ROffset >= LowerOffset && *ROffset < UpperOffset) ||
1185  (UpperOverflow &&
1186  (*ROffset >= LowerOffset || *ROffset < UpperOffset)) ||
1187  (LowerOffset == UpperOffset && *ROffset == LowerOffset))) {
1188  B = B.removeBinding(I.getKey());
1189  // Bound symbolic regions need to be invalidated for dead symbol
1190  // detection.
1191  SVal V = I.getData();
1192  const MemRegion *R = V.getAsRegion();
1193  if (R && isa<SymbolicRegion>(R))
1194  VisitBinding(V);
1195  }
1196  }
1197  }
1198  conjure_default:
1199  // Set the default value of the array to conjured symbol.
1200  DefinedOrUnknownSVal V =
1201  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1202  AT->getElementType(), Count);
1203  B = B.addBinding(baseR, BindingKey::Default, V);
1204  return;
1205  }
1206 
1207  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1208  T,Count);
1209  assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
1210  B = B.addBinding(baseR, BindingKey::Direct, V);
1211 }
1212 
1213 bool InvalidateRegionsWorker::isInitiallyIncludedGlobalRegion(
1214  const MemRegion *R) {
1215  switch (GlobalsFilter) {
1216  case GFK_None:
1217  return false;
1218  case GFK_SystemOnly:
1219  return isa<GlobalSystemSpaceRegion>(R->getMemorySpace());
1220  case GFK_All:
1221  return isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace());
1222  }
1223 
1224  llvm_unreachable("unknown globals filter");
1225 }
1226 
1227 bool InvalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) {
1228  if (isInitiallyIncludedGlobalRegion(Base))
1229  return true;
1230 
1231  const MemSpaceRegion *MemSpace = Base->getMemorySpace();
1232  return ITraits.hasTrait(MemSpace,
1234 }
1235 
1236 RegionBindingsRef
1237 RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K,
1238  const Expr *Ex,
1239  unsigned Count,
1240  const LocationContext *LCtx,
1241  RegionBindingsRef B,
1242  InvalidatedRegions *Invalidated) {
1243  // Bind the globals memory space to a new symbol that we will use to derive
1244  // the bindings for all globals.
1245  const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K);
1246  SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx,
1247  /* type does not matter */ Ctx.IntTy,
1248  Count);
1249 
1250  B = B.removeBinding(GS)
1251  .addBinding(BindingKey::Make(GS, BindingKey::Default), V);
1252 
1253  // Even if there are no bindings in the global scope, we still need to
1254  // record that we touched it.
1255  if (Invalidated)
1256  Invalidated->push_back(GS);
1257 
1258  return B;
1259 }
1260 
1261 void RegionStoreManager::populateWorkList(InvalidateRegionsWorker &W,
1262  ArrayRef<SVal> Values,
1263  InvalidatedRegions *TopLevelRegions) {
1264  for (ArrayRef<SVal>::iterator I = Values.begin(),
1265  E = Values.end(); I != E; ++I) {
1266  SVal V = *I;
1268  V.getAs<nonloc::LazyCompoundVal>()) {
1269 
1270  const SValListTy &Vals = getInterestingValues(*LCS);
1271 
1272  for (SValListTy::const_iterator I = Vals.begin(),
1273  E = Vals.end(); I != E; ++I) {
1274  // Note: the last argument is false here because these are
1275  // non-top-level regions.
1276  if (const MemRegion *R = (*I).getAsRegion())
1277  W.AddToWorkList(R);
1278  }
1279  continue;
1280  }
1281 
1282  if (const MemRegion *R = V.getAsRegion()) {
1283  if (TopLevelRegions)
1284  TopLevelRegions->push_back(R);
1285  W.AddToWorkList(R);
1286  continue;
1287  }
1288  }
1289 }
1290 
1291 StoreRef
1292 RegionStoreManager::invalidateRegions(Store store,
1293  ArrayRef<SVal> Values,
1294  const Expr *Ex, unsigned Count,
1295  const LocationContext *LCtx,
1296  const CallEvent *Call,
1297  InvalidatedSymbols &IS,
1298  RegionAndSymbolInvalidationTraits &ITraits,
1299  InvalidatedRegions *TopLevelRegions,
1300  InvalidatedRegions *Invalidated) {
1301  GlobalsFilterKind GlobalsFilter;
1302  if (Call) {
1303  if (Call->isInSystemHeader())
1304  GlobalsFilter = GFK_SystemOnly;
1305  else
1306  GlobalsFilter = GFK_All;
1307  } else {
1308  GlobalsFilter = GFK_None;
1309  }
1310 
1311  RegionBindingsRef B = getRegionBindings(store);
1312  InvalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, ITraits,
1313  Invalidated, GlobalsFilter);
1314 
1315  // Scan the bindings and generate the clusters.
1316  W.GenerateClusters();
1317 
1318  // Add the regions to the worklist.
1319  populateWorkList(W, Values, TopLevelRegions);
1320 
1321  W.RunWorkList();
1322 
1323  // Return the new bindings.
1324  B = W.getRegionBindings();
1325 
1326  // For calls, determine which global regions should be invalidated and
1327  // invalidate them. (Note that function-static and immutable globals are never
1328  // invalidated by this.)
1329  // TODO: This could possibly be more precise with modules.
1330  switch (GlobalsFilter) {
1331  case GFK_All:
1332  B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind,
1333  Ex, Count, LCtx, B, Invalidated);
1334  // FALLTHROUGH
1335  case GFK_SystemOnly:
1336  B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
1337  Ex, Count, LCtx, B, Invalidated);
1338  // FALLTHROUGH
1339  case GFK_None:
1340  break;
1341  }
1342 
1343  return StoreRef(B.asStore(), *this);
1344 }
1345 
1346 //===----------------------------------------------------------------------===//
1347 // Extents for regions.
1348 //===----------------------------------------------------------------------===//
1349 
1350 DefinedOrUnknownSVal
1351 RegionStoreManager::getSizeInElements(ProgramStateRef state,
1352  const MemRegion *R,
1353  QualType EleTy) {
1354  SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder);
1355  const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size);
1356  if (!SizeInt)
1357  return UnknownVal();
1358 
1359  CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue());
1360 
1361  if (Ctx.getAsVariableArrayType(EleTy)) {
1362  // FIXME: We need to track extra state to properly record the size
1363  // of VLAs. Returning UnknownVal here, however, is a stop-gap so that
1364  // we don't have a divide-by-zero below.
1365  return UnknownVal();
1366  }
1367 
1368  CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy);
1369 
1370  // If a variable is reinterpreted as a type that doesn't fit into a larger
1371  // type evenly, round it down.
1372  // This is a signed value, since it's used in arithmetic with signed indices.
1373  return svalBuilder.makeIntVal(RegionSize / EleSize,
1374  svalBuilder.getArrayIndexType());
1375 }
1376 
1377 //===----------------------------------------------------------------------===//
1378 // Location and region casting.
1379 //===----------------------------------------------------------------------===//
1380 
1381 /// ArrayToPointer - Emulates the "decay" of an array to a pointer
1382 /// type. 'Array' represents the lvalue of the array being decayed
1383 /// to a pointer, and the returned SVal represents the decayed
1384 /// version of that lvalue (i.e., a pointer to the first element of
1385 /// the array). This is called by ExprEngine when evaluating casts
1386 /// from arrays to pointers.
1387 SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) {
1388  if (Array.getAs<loc::ConcreteInt>())
1389  return Array;
1390 
1391  if (!Array.getAs<loc::MemRegionVal>())
1392  return UnknownVal();
1393 
1394  const SubRegion *R =
1395  cast<SubRegion>(Array.castAs<loc::MemRegionVal>().getRegion());
1396  NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
1397  return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, R, Ctx));
1398 }
1399 
1400 //===----------------------------------------------------------------------===//
1401 // Loading values from regions.
1402 //===----------------------------------------------------------------------===//
1403 
1404 SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) {
1405  assert(!L.getAs<UnknownVal>() && "location unknown");
1406  assert(!L.getAs<UndefinedVal>() && "location undefined");
1407 
1408  // For access to concrete addresses, return UnknownVal. Checks
1409  // for null dereferences (and similar errors) are done by checkers, not
1410  // the Store.
1411  // FIXME: We can consider lazily symbolicating such memory, but we really
1412  // should defer this when we can reason easily about symbolicating arrays
1413  // of bytes.
1414  if (L.getAs<loc::ConcreteInt>()) {
1415  return UnknownVal();
1416  }
1417  if (!L.getAs<loc::MemRegionVal>()) {
1418  return UnknownVal();
1419  }
1420 
1421  const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion();
1422 
1423  if (isa<BlockDataRegion>(MR)) {
1424  return UnknownVal();
1425  }
1426 
1427  if (!isa<TypedValueRegion>(MR)) {
1428  if (T.isNull()) {
1429  if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
1430  T = TR->getLocationType()->getPointeeType();
1431  else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1432  T = SR->getSymbol()->getType()->getPointeeType();
1433  }
1434  assert(!T.isNull() && "Unable to auto-detect binding type!");
1435  assert(!T->isVoidType() && "Attempting to dereference a void pointer!");
1436  MR = GetElementZeroRegion(cast<SubRegion>(MR), T);
1437  } else {
1438  T = cast<TypedValueRegion>(MR)->getValueType();
1439  }
1440 
1441  // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
1442  // instead of 'Loc', and have the other Loc cases handled at a higher level.
1443  const TypedValueRegion *R = cast<TypedValueRegion>(MR);
1444  QualType RTy = R->getValueType();
1445 
1446  // FIXME: we do not yet model the parts of a complex type, so treat the
1447  // whole thing as "unknown".
1448  if (RTy->isAnyComplexType())
1449  return UnknownVal();
1450 
1451  // FIXME: We should eventually handle funny addressing. e.g.:
1452  //
1453  // int x = ...;
1454  // int *p = &x;
1455  // char *q = (char*) p;
1456  // char c = *q; // returns the first byte of 'x'.
1457  //
1458  // Such funny addressing will occur due to layering of regions.
1459  if (RTy->isStructureOrClassType())
1460  return getBindingForStruct(B, R);
1461 
1462  // FIXME: Handle unions.
1463  if (RTy->isUnionType())
1464  return createLazyBinding(B, R);
1465 
1466  if (RTy->isArrayType()) {
1467  if (RTy->isConstantArrayType())
1468  return getBindingForArray(B, R);
1469  else
1470  return UnknownVal();
1471  }
1472 
1473  // FIXME: handle Vector types.
1474  if (RTy->isVectorType())
1475  return UnknownVal();
1476 
1477  if (const FieldRegion* FR = dyn_cast<FieldRegion>(R))
1478  return CastRetrievedVal(getBindingForField(B, FR), FR, T);
1479 
1480  if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
1481  // FIXME: Here we actually perform an implicit conversion from the loaded
1482  // value to the element type. Eventually we want to compose these values
1483  // more intelligently. For example, an 'element' can encompass multiple
1484  // bound regions (e.g., several bound bytes), or could be a subset of
1485  // a larger value.
1486  return CastRetrievedVal(getBindingForElement(B, ER), ER, T);
1487  }
1488 
1489  if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) {
1490  // FIXME: Here we actually perform an implicit conversion from the loaded
1491  // value to the ivar type. What we should model is stores to ivars
1492  // that blow past the extent of the ivar. If the address of the ivar is
1493  // reinterpretted, it is possible we stored a different value that could
1494  // fit within the ivar. Either we need to cast these when storing them
1495  // or reinterpret them lazily (as we do here).
1496  return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T);
1497  }
1498 
1499  if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
1500  // FIXME: Here we actually perform an implicit conversion from the loaded
1501  // value to the variable type. What we should model is stores to variables
1502  // that blow past the extent of the variable. If the address of the
1503  // variable is reinterpretted, it is possible we stored a different value
1504  // that could fit within the variable. Either we need to cast these when
1505  // storing them or reinterpret them lazily (as we do here).
1506  return CastRetrievedVal(getBindingForVar(B, VR), VR, T);
1507  }
1508 
1509  const SVal *V = B.lookup(R, BindingKey::Direct);
1510 
1511  // Check if the region has a binding.
1512  if (V)
1513  return *V;
1514 
1515  // The location does not have a bound value. This means that it has
1516  // the value it had upon its creation and/or entry to the analyzed
1517  // function/method. These are either symbolic values or 'undefined'.
1518  if (R->hasStackNonParametersStorage()) {
1519  // All stack variables are considered to have undefined values
1520  // upon creation. All heap allocated blocks are considered to
1521  // have undefined values as well unless they are explicitly bound
1522  // to specific values.
1523  return UndefinedVal();
1524  }
1525 
1526  // All other values are symbolic.
1527  return svalBuilder.getRegionValueSymbolVal(R);
1528 }
1529 
1530 static QualType getUnderlyingType(const SubRegion *R) {
1531  QualType RegionTy;
1532  if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R))
1533  RegionTy = TVR->getValueType();
1534 
1535  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1536  RegionTy = SR->getSymbol()->getType();
1537 
1538  return RegionTy;
1539 }
1540 
1541 /// Checks to see if store \p B has a lazy binding for region \p R.
1542 ///
1543 /// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected
1544 /// if there are additional bindings within \p R.
1545 ///
1546 /// Note that unlike RegionStoreManager::findLazyBinding, this will not search
1547 /// for lazy bindings for super-regions of \p R.
1549 getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B,
1550  const SubRegion *R, bool AllowSubregionBindings) {
1551  Optional<SVal> V = B.getDefaultBinding(R);
1552  if (!V)
1553  return None;
1554 
1555  Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>();
1556  if (!LCV)
1557  return None;
1558 
1559  // If the LCV is for a subregion, the types might not match, and we shouldn't
1560  // reuse the binding.
1561  QualType RegionTy = getUnderlyingType(R);
1562  if (!RegionTy.isNull() &&
1563  !RegionTy->isVoidPointerType()) {
1564  QualType SourceRegionTy = LCV->getRegion()->getValueType();
1565  if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy))
1566  return None;
1567  }
1568 
1569  if (!AllowSubregionBindings) {
1570  // If there are any other bindings within this region, we shouldn't reuse
1571  // the top-level binding.
1573  collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R,
1574  /*IncludeAllDefaultBindings=*/true);
1575  if (Bindings.size() > 1)
1576  return None;
1577  }
1578 
1579  return *LCV;
1580 }
1581 
1582 
1583 std::pair<Store, const SubRegion *>
1584 RegionStoreManager::findLazyBinding(RegionBindingsConstRef B,
1585  const SubRegion *R,
1586  const SubRegion *originalRegion) {
1587  if (originalRegion != R) {
1589  getExistingLazyBinding(svalBuilder, B, R, true))
1590  return std::make_pair(V->getStore(), V->getRegion());
1591  }
1592 
1593  typedef std::pair<Store, const SubRegion *> StoreRegionPair;
1594  StoreRegionPair Result = StoreRegionPair();
1595 
1596  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
1597  Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()),
1598  originalRegion);
1599 
1600  if (Result.second)
1601  Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second);
1602 
1603  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
1604  Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()),
1605  originalRegion);
1606 
1607  if (Result.second)
1608  Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second);
1609 
1610  } else if (const CXXBaseObjectRegion *BaseReg =
1611  dyn_cast<CXXBaseObjectRegion>(R)) {
1612  // C++ base object region is another kind of region that we should blast
1613  // through to look for lazy compound value. It is like a field region.
1614  Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()),
1615  originalRegion);
1616 
1617  if (Result.second)
1618  Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg,
1619  Result.second);
1620  }
1621 
1622  return Result;
1623 }
1624 
1625 SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B,
1626  const ElementRegion* R) {
1627  // We do not currently model bindings of the CompoundLiteralregion.
1628  if (isa<CompoundLiteralRegion>(R->getBaseRegion()))
1629  return UnknownVal();
1630 
1631  // Check if the region has a binding.
1632  if (const Optional<SVal> &V = B.getDirectBinding(R))
1633  return *V;
1634 
1635  const MemRegion* superR = R->getSuperRegion();
1636 
1637  // Check if the region is an element region of a string literal.
1638  if (const StringRegion *StrR = dyn_cast<StringRegion>(superR)) {
1639  // FIXME: Handle loads from strings where the literal is treated as
1640  // an integer, e.g., *((unsigned int*)"hello")
1641  QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType();
1642  if (!Ctx.hasSameUnqualifiedType(T, R->getElementType()))
1643  return UnknownVal();
1644 
1645  const StringLiteral *Str = StrR->getStringLiteral();
1646  SVal Idx = R->getIndex();
1647  if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) {
1648  int64_t i = CI->getValue().getSExtValue();
1649  // Abort on string underrun. This can be possible by arbitrary
1650  // clients of getBindingForElement().
1651  if (i < 0)
1652  return UndefinedVal();
1653  int64_t length = Str->getLength();
1654  // Technically, only i == length is guaranteed to be null.
1655  // However, such overflows should be caught before reaching this point;
1656  // the only time such an access would be made is if a string literal was
1657  // used to initialize a larger array.
1658  char c = (i >= length) ? '\0' : Str->getCodeUnit(i);
1659  return svalBuilder.makeIntVal(c, T);
1660  }
1661  } else if (const VarRegion *VR = dyn_cast<VarRegion>(superR)) {
1662  // Check if the containing array is const and has an initialized value.
1663  const VarDecl *VD = VR->getDecl();
1664  // Either the array or the array element has to be const.
1665  if (VD->getType().isConstQualified() || R->getElementType().isConstQualified()) {
1666  if (const Expr *Init = VD->getInit()) {
1667  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1668  // The array index has to be known.
1669  if (auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) {
1670  int64_t i = CI->getValue().getSExtValue();
1671  // If it is known that the index is out of bounds, we can return
1672  // an undefined value.
1673  if (i < 0)
1674  return UndefinedVal();
1675 
1676  if (auto CAT = Ctx.getAsConstantArrayType(VD->getType()))
1677  if (CAT->getSize().sle(i))
1678  return UndefinedVal();
1679 
1680  // If there is a list, but no init, it must be zero.
1681  if (i >= InitList->getNumInits())
1682  return svalBuilder.makeZeroVal(R->getElementType());
1683 
1684  if (const Expr *ElemInit = InitList->getInit(i))
1685  if (Optional<SVal> V = svalBuilder.getConstantVal(ElemInit))
1686  return *V;
1687  }
1688  }
1689  }
1690  }
1691  }
1692 
1693  // Check for loads from a code text region. For such loads, just give up.
1694  if (isa<CodeTextRegion>(superR))
1695  return UnknownVal();
1696 
1697  // Handle the case where we are indexing into a larger scalar object.
1698  // For example, this handles:
1699  // int x = ...
1700  // char *y = &x;
1701  // return *y;
1702  // FIXME: This is a hack, and doesn't do anything really intelligent yet.
1703  const RegionRawOffset &O = R->getAsArrayOffset();
1704 
1705  // If we cannot reason about the offset, return an unknown value.
1706  if (!O.getRegion())
1707  return UnknownVal();
1708 
1709  if (const TypedValueRegion *baseR =
1710  dyn_cast_or_null<TypedValueRegion>(O.getRegion())) {
1711  QualType baseT = baseR->getValueType();
1712  if (baseT->isScalarType()) {
1713  QualType elemT = R->getElementType();
1714  if (elemT->isScalarType()) {
1715  if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) {
1716  if (const Optional<SVal> &V = B.getDirectBinding(superR)) {
1717  if (SymbolRef parentSym = V->getAsSymbol())
1718  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1719 
1720  if (V->isUnknownOrUndef())
1721  return *V;
1722  // Other cases: give up. We are indexing into a larger object
1723  // that has some value, but we don't know how to handle that yet.
1724  return UnknownVal();
1725  }
1726  }
1727  }
1728  }
1729  }
1730  return getBindingForFieldOrElementCommon(B, R, R->getElementType());
1731 }
1732 
1733 SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B,
1734  const FieldRegion* R) {
1735 
1736  // Check if the region has a binding.
1737  if (const Optional<SVal> &V = B.getDirectBinding(R))
1738  return *V;
1739 
1740  // Is the field declared constant and has an in-class initializer?
1741  const FieldDecl *FD = R->getDecl();
1742  QualType Ty = FD->getType();
1743  if (Ty.isConstQualified())
1744  if (const Expr *Init = FD->getInClassInitializer())
1745  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1746  return *V;
1747 
1748  // If the containing record was initialized, try to get its constant value.
1749  const MemRegion* superR = R->getSuperRegion();
1750  if (const auto *VR = dyn_cast<VarRegion>(superR)) {
1751  const VarDecl *VD = VR->getDecl();
1752  QualType RecordVarTy = VD->getType();
1753  unsigned Index = FD->getFieldIndex();
1754  // Either the record variable or the field has to be const qualified.
1755  if (RecordVarTy.isConstQualified() || Ty.isConstQualified())
1756  if (const Expr *Init = VD->getInit())
1757  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1758  if (Index < InitList->getNumInits()) {
1759  if (const Expr *FieldInit = InitList->getInit(Index))
1760  if (Optional<SVal> V = svalBuilder.getConstantVal(FieldInit))
1761  return *V;
1762  } else {
1763  return svalBuilder.makeZeroVal(Ty);
1764  }
1765  }
1766  }
1767 
1768  return getBindingForFieldOrElementCommon(B, R, Ty);
1769 }
1770 
1772 RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
1773  const MemRegion *superR,
1774  const TypedValueRegion *R,
1775  QualType Ty) {
1776 
1777  if (const Optional<SVal> &D = B.getDefaultBinding(superR)) {
1778  const SVal &val = D.getValue();
1779  if (SymbolRef parentSym = val.getAsSymbol())
1780  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1781 
1782  if (val.isZeroConstant())
1783  return svalBuilder.makeZeroVal(Ty);
1784 
1785  if (val.isUnknownOrUndef())
1786  return val;
1787 
1788  // Lazy bindings are usually handled through getExistingLazyBinding().
1789  // We should unify these two code paths at some point.
1790  if (val.getAs<nonloc::LazyCompoundVal>() ||
1791  val.getAs<nonloc::CompoundVal>())
1792  return val;
1793 
1794  llvm_unreachable("Unknown default value");
1795  }
1796 
1797  return None;
1798 }
1799 
1800 SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion,
1801  RegionBindingsRef LazyBinding) {
1802  SVal Result;
1803  if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion))
1804  Result = getBindingForElement(LazyBinding, ER);
1805  else
1806  Result = getBindingForField(LazyBinding,
1807  cast<FieldRegion>(LazyBindingRegion));
1808 
1809  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1810  // default value for /part/ of an aggregate from a default value for the
1811  // /entire/ aggregate. The most common case of this is when struct Outer
1812  // has as its first member a struct Inner, which is copied in from a stack
1813  // variable. In this case, even if the Outer's default value is symbolic, 0,
1814  // or unknown, it gets overridden by the Inner's default value of undefined.
1815  //
1816  // This is a general problem -- if the Inner is zero-initialized, the Outer
1817  // will now look zero-initialized. The proper way to solve this is with a
1818  // new version of RegionStore that tracks the extent of a binding as well
1819  // as the offset.
1820  //
1821  // This hack only takes care of the undefined case because that can very
1822  // quickly result in a warning.
1823  if (Result.isUndef())
1824  Result = UnknownVal();
1825 
1826  return Result;
1827 }
1828 
1829 SVal
1830 RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
1831  const TypedValueRegion *R,
1832  QualType Ty) {
1833 
1834  // At this point we have already checked in either getBindingForElement or
1835  // getBindingForField if 'R' has a direct binding.
1836 
1837  // Lazy binding?
1838  Store lazyBindingStore = nullptr;
1839  const SubRegion *lazyBindingRegion = nullptr;
1840  std::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R);
1841  if (lazyBindingRegion)
1842  return getLazyBinding(lazyBindingRegion,
1843  getRegionBindings(lazyBindingStore));
1844 
1845  // Record whether or not we see a symbolic index. That can completely
1846  // be out of scope of our lookup.
1847  bool hasSymbolicIndex = false;
1848 
1849  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1850  // default value for /part/ of an aggregate from a default value for the
1851  // /entire/ aggregate. The most common case of this is when struct Outer
1852  // has as its first member a struct Inner, which is copied in from a stack
1853  // variable. In this case, even if the Outer's default value is symbolic, 0,
1854  // or unknown, it gets overridden by the Inner's default value of undefined.
1855  //
1856  // This is a general problem -- if the Inner is zero-initialized, the Outer
1857  // will now look zero-initialized. The proper way to solve this is with a
1858  // new version of RegionStore that tracks the extent of a binding as well
1859  // as the offset.
1860  //
1861  // This hack only takes care of the undefined case because that can very
1862  // quickly result in a warning.
1863  bool hasPartialLazyBinding = false;
1864 
1865  const SubRegion *SR = R;
1866  while (SR) {
1867  const MemRegion *Base = SR->getSuperRegion();
1868  if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) {
1869  if (D->getAs<nonloc::LazyCompoundVal>()) {
1870  hasPartialLazyBinding = true;
1871  break;
1872  }
1873 
1874  return *D;
1875  }
1876 
1877  if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) {
1878  NonLoc index = ER->getIndex();
1879  if (!index.isConstant())
1880  hasSymbolicIndex = true;
1881  }
1882 
1883  // If our super region is a field or element itself, walk up the region
1884  // hierarchy to see if there is a default value installed in an ancestor.
1885  SR = dyn_cast<SubRegion>(Base);
1886  }
1887 
1888  if (R->hasStackNonParametersStorage()) {
1889  if (isa<ElementRegion>(R)) {
1890  // Currently we don't reason specially about Clang-style vectors. Check
1891  // if superR is a vector and if so return Unknown.
1892  if (const TypedValueRegion *typedSuperR =
1893  dyn_cast<TypedValueRegion>(R->getSuperRegion())) {
1894  if (typedSuperR->getValueType()->isVectorType())
1895  return UnknownVal();
1896  }
1897  }
1898 
1899  // FIXME: We also need to take ElementRegions with symbolic indexes into
1900  // account. This case handles both directly accessing an ElementRegion
1901  // with a symbolic offset, but also fields within an element with
1902  // a symbolic offset.
1903  if (hasSymbolicIndex)
1904  return UnknownVal();
1905 
1906  if (!hasPartialLazyBinding)
1907  return UndefinedVal();
1908  }
1909 
1910  // All other values are symbolic.
1911  return svalBuilder.getRegionValueSymbolVal(R);
1912 }
1913 
1914 SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B,
1915  const ObjCIvarRegion* R) {
1916  // Check if the region has a binding.
1917  if (const Optional<SVal> &V = B.getDirectBinding(R))
1918  return *V;
1919 
1920  const MemRegion *superR = R->getSuperRegion();
1921 
1922  // Check if the super region has a default binding.
1923  if (const Optional<SVal> &V = B.getDefaultBinding(superR)) {
1924  if (SymbolRef parentSym = V->getAsSymbol())
1925  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1926 
1927  // Other cases: give up.
1928  return UnknownVal();
1929  }
1930 
1931  return getBindingForLazySymbol(R);
1932 }
1933 
1934 SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B,
1935  const VarRegion *R) {
1936 
1937  // Check if the region has a binding.
1938  if (const Optional<SVal> &V = B.getDirectBinding(R))
1939  return *V;
1940 
1941  // Lazily derive a value for the VarRegion.
1942  const VarDecl *VD = R->getDecl();
1943  const MemSpaceRegion *MS = R->getMemorySpace();
1944 
1945  // Arguments are always symbolic.
1946  if (isa<StackArgumentsSpaceRegion>(MS))
1947  return svalBuilder.getRegionValueSymbolVal(R);
1948 
1949  // Is 'VD' declared constant? If so, retrieve the constant value.
1950  if (VD->getType().isConstQualified()) {
1951  if (const Expr *Init = VD->getInit()) {
1952  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1953  return *V;
1954 
1955  // If the variable is const qualified and has an initializer but
1956  // we couldn't evaluate initializer to a value, treat the value as
1957  // unknown.
1958  return UnknownVal();
1959  }
1960  }
1961 
1962  // This must come after the check for constants because closure-captured
1963  // constant variables may appear in UnknownSpaceRegion.
1964  if (isa<UnknownSpaceRegion>(MS))
1965  return svalBuilder.getRegionValueSymbolVal(R);
1966 
1967  if (isa<GlobalsSpaceRegion>(MS)) {
1968  QualType T = VD->getType();
1969 
1970  // Function-scoped static variables are default-initialized to 0; if they
1971  // have an initializer, it would have been processed by now.
1972  // FIXME: This is only true when we're starting analysis from main().
1973  // We're losing a lot of coverage here.
1974  if (isa<StaticGlobalSpaceRegion>(MS))
1975  return svalBuilder.makeZeroVal(T);
1976 
1977  if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) {
1978  assert(!V->getAs<nonloc::LazyCompoundVal>());
1979  return V.getValue();
1980  }
1981 
1982  return svalBuilder.getRegionValueSymbolVal(R);
1983  }
1984 
1985  return UndefinedVal();
1986 }
1987 
1988 SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
1989  // All other values are symbolic.
1990  return svalBuilder.getRegionValueSymbolVal(R);
1991 }
1992 
1993 const RegionStoreManager::SValListTy &
1994 RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) {
1995  // First, check the cache.
1996  LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData());
1997  if (I != LazyBindingsMap.end())
1998  return I->second;
1999 
2000  // If we don't have a list of values cached, start constructing it.
2001  SValListTy List;
2002 
2003  const SubRegion *LazyR = LCV.getRegion();
2004  RegionBindingsRef B = getRegionBindings(LCV.getStore());
2005 
2006  // If this region had /no/ bindings at the time, there are no interesting
2007  // values to return.
2008  const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion());
2009  if (!Cluster)
2010  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2011 
2013  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR,
2014  /*IncludeAllDefaultBindings=*/true);
2015  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
2016  E = Bindings.end();
2017  I != E; ++I) {
2018  SVal V = I->second;
2019  if (V.isUnknownOrUndef() || V.isConstant())
2020  continue;
2021 
2022  if (Optional<nonloc::LazyCompoundVal> InnerLCV =
2023  V.getAs<nonloc::LazyCompoundVal>()) {
2024  const SValListTy &InnerList = getInterestingValues(*InnerLCV);
2025  List.insert(List.end(), InnerList.begin(), InnerList.end());
2026  continue;
2027  }
2028 
2029  List.push_back(V);
2030  }
2031 
2032  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2033 }
2034 
2035 NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B,
2036  const TypedValueRegion *R) {
2038  getExistingLazyBinding(svalBuilder, B, R, false))
2039  return *V;
2040 
2041  return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R);
2042 }
2043 
2044 static bool isRecordEmpty(const RecordDecl *RD) {
2045  if (!RD->field_empty())
2046  return false;
2047  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD))
2048  return CRD->getNumBases() == 0;
2049  return true;
2050 }
2051 
2052 SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B,
2053  const TypedValueRegion *R) {
2054  const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl();
2055  if (!RD->getDefinition() || isRecordEmpty(RD))
2056  return UnknownVal();
2057 
2058  return createLazyBinding(B, R);
2059 }
2060 
2061 SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B,
2062  const TypedValueRegion *R) {
2063  assert(Ctx.getAsConstantArrayType(R->getValueType()) &&
2064  "Only constant array types can have compound bindings.");
2065 
2066  return createLazyBinding(B, R);
2067 }
2068 
2069 bool RegionStoreManager::includedInBindings(Store store,
2070  const MemRegion *region) const {
2071  RegionBindingsRef B = getRegionBindings(store);
2072  region = region->getBaseRegion();
2073 
2074  // Quick path: if the base is the head of a cluster, the region is live.
2075  if (B.lookup(region))
2076  return true;
2077 
2078  // Slow path: if the region is the VALUE of any binding, it is live.
2079  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) {
2080  const ClusterBindings &Cluster = RI.getData();
2081  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2082  CI != CE; ++CI) {
2083  const SVal &D = CI.getData();
2084  if (const MemRegion *R = D.getAsRegion())
2085  if (R->getBaseRegion() == region)
2086  return true;
2087  }
2088  }
2089 
2090  return false;
2091 }
2092 
2093 //===----------------------------------------------------------------------===//
2094 // Binding values to regions.
2095 //===----------------------------------------------------------------------===//
2096 
2097 StoreRef RegionStoreManager::killBinding(Store ST, Loc L) {
2098  if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>())
2099  if (const MemRegion* R = LV->getRegion())
2100  return StoreRef(getRegionBindings(ST).removeBinding(R)
2101  .asImmutableMap()
2102  .getRootWithoutRetain(),
2103  *this);
2104 
2105  return StoreRef(ST, *this);
2106 }
2107 
2108 RegionBindingsRef
2109 RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) {
2110  if (L.getAs<loc::ConcreteInt>())
2111  return B;
2112 
2113  // If we get here, the location should be a region.
2114  const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion();
2115 
2116  // Check if the region is a struct region.
2117  if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) {
2118  QualType Ty = TR->getValueType();
2119  if (Ty->isArrayType())
2120  return bindArray(B, TR, V);
2121  if (Ty->isStructureOrClassType())
2122  return bindStruct(B, TR, V);
2123  if (Ty->isVectorType())
2124  return bindVector(B, TR, V);
2125  if (Ty->isUnionType())
2126  return bindAggregate(B, TR, V);
2127  }
2128 
2129  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
2130  // Binding directly to a symbolic region should be treated as binding
2131  // to element 0.
2132  QualType T = SR->getSymbol()->getType();
2133  if (T->isAnyPointerType() || T->isReferenceType())
2134  T = T->getPointeeType();
2135 
2136  R = GetElementZeroRegion(SR, T);
2137  }
2138 
2139  assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) &&
2140  "'this' pointer is not an l-value and is not assignable");
2141 
2142  // Clear out bindings that may overlap with this binding.
2143  RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R));
2144  return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V);
2145 }
2146 
2147 RegionBindingsRef
2148 RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B,
2149  const MemRegion *R,
2150  QualType T) {
2151  SVal V;
2152 
2153  if (Loc::isLocType(T))
2154  V = svalBuilder.makeNull();
2155  else if (T->isIntegralOrEnumerationType())
2156  V = svalBuilder.makeZeroVal(T);
2157  else if (T->isStructureOrClassType() || T->isArrayType()) {
2158  // Set the default value to a zero constant when it is a structure
2159  // or array. The type doesn't really matter.
2160  V = svalBuilder.makeZeroVal(Ctx.IntTy);
2161  }
2162  else {
2163  // We can't represent values of this type, but we still need to set a value
2164  // to record that the region has been initialized.
2165  // If this assertion ever fires, a new case should be added above -- we
2166  // should know how to default-initialize any value we can symbolicate.
2167  assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
2168  V = UnknownVal();
2169  }
2170 
2171  return B.addBinding(R, BindingKey::Default, V);
2172 }
2173 
2174 RegionBindingsRef
2175 RegionStoreManager::bindArray(RegionBindingsConstRef B,
2176  const TypedValueRegion* R,
2177  SVal Init) {
2178 
2179  const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType()));
2180  QualType ElementTy = AT->getElementType();
2181  Optional<uint64_t> Size;
2182 
2183  if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT))
2184  Size = CAT->getSize().getZExtValue();
2185 
2186  // Check if the init expr is a literal. If so, bind the rvalue instead.
2187  // FIXME: It's not responsibility of the Store to transform this lvalue
2188  // to rvalue. ExprEngine or maybe even CFG should do this before binding.
2189  if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) {
2190  SVal V = getBinding(B.asStore(), *MRV, R->getValueType());
2191  return bindAggregate(B, R, V);
2192  }
2193 
2194  // Handle lazy compound values.
2195  if (Init.getAs<nonloc::LazyCompoundVal>())
2196  return bindAggregate(B, R, Init);
2197 
2198  if (Init.isUnknown())
2199  return bindAggregate(B, R, UnknownVal());
2200 
2201  // Remaining case: explicit compound values.
2202  const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>();
2203  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2204  uint64_t i = 0;
2205 
2206  RegionBindingsRef NewB(B);
2207 
2208  for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) {
2209  // The init list might be shorter than the array length.
2210  if (VI == VE)
2211  break;
2212 
2213  const NonLoc &Idx = svalBuilder.makeArrayIndex(i);
2214  const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx);
2215 
2216  if (ElementTy->isStructureOrClassType())
2217  NewB = bindStruct(NewB, ER, *VI);
2218  else if (ElementTy->isArrayType())
2219  NewB = bindArray(NewB, ER, *VI);
2220  else
2221  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2222  }
2223 
2224  // If the init list is shorter than the array length (or the array has
2225  // variable length), set the array default value. Values that are already set
2226  // are not overwritten.
2227  if (!Size.hasValue() || i < Size.getValue())
2228  NewB = setImplicitDefaultValue(NewB, R, ElementTy);
2229 
2230  return NewB;
2231 }
2232 
2233 RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B,
2234  const TypedValueRegion* R,
2235  SVal V) {
2236  QualType T = R->getValueType();
2237  assert(T->isVectorType());
2238  const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs.
2239 
2240  // Handle lazy compound values and symbolic values.
2241  if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>())
2242  return bindAggregate(B, R, V);
2243 
2244  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2245  // that we are binding symbolic struct value. Kill the field values, and if
2246  // the value is symbolic go and bind it as a "default" binding.
2247  if (!V.getAs<nonloc::CompoundVal>()) {
2248  return bindAggregate(B, R, UnknownVal());
2249  }
2250 
2251  QualType ElemType = VT->getElementType();
2252  nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>();
2253  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2254  unsigned index = 0, numElements = VT->getNumElements();
2255  RegionBindingsRef NewB(B);
2256 
2257  for ( ; index != numElements ; ++index) {
2258  if (VI == VE)
2259  break;
2260 
2261  NonLoc Idx = svalBuilder.makeArrayIndex(index);
2262  const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx);
2263 
2264  if (ElemType->isArrayType())
2265  NewB = bindArray(NewB, ER, *VI);
2266  else if (ElemType->isStructureOrClassType())
2267  NewB = bindStruct(NewB, ER, *VI);
2268  else
2269  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2270  }
2271  return NewB;
2272 }
2273 
2275 RegionStoreManager::tryBindSmallStruct(RegionBindingsConstRef B,
2276  const TypedValueRegion *R,
2277  const RecordDecl *RD,
2278  nonloc::LazyCompoundVal LCV) {
2279  FieldVector Fields;
2280 
2281  if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(RD))
2282  if (Class->getNumBases() != 0 || Class->getNumVBases() != 0)
2283  return None;
2284 
2285  for (const auto *FD : RD->fields()) {
2286  if (FD->isUnnamedBitfield())
2287  continue;
2288 
2289  // If there are too many fields, or if any of the fields are aggregates,
2290  // just use the LCV as a default binding.
2291  if (Fields.size() == SmallStructLimit)
2292  return None;
2293 
2294  QualType Ty = FD->getType();
2295  if (!(Ty->isScalarType() || Ty->isReferenceType()))
2296  return None;
2297 
2298  Fields.push_back(FD);
2299  }
2300 
2301  RegionBindingsRef NewB = B;
2302 
2303  for (FieldVector::iterator I = Fields.begin(), E = Fields.end(); I != E; ++I){
2304  const FieldRegion *SourceFR = MRMgr.getFieldRegion(*I, LCV.getRegion());
2305  SVal V = getBindingForField(getRegionBindings(LCV.getStore()), SourceFR);
2306 
2307  const FieldRegion *DestFR = MRMgr.getFieldRegion(*I, R);
2308  NewB = bind(NewB, loc::MemRegionVal(DestFR), V);
2309  }
2310 
2311  return NewB;
2312 }
2313 
2314 RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B,
2315  const TypedValueRegion* R,
2316  SVal V) {
2317  if (!Features.supportsFields())
2318  return B;
2319 
2320  QualType T = R->getValueType();
2321  assert(T->isStructureOrClassType());
2322 
2323  const RecordType* RT = T->getAs<RecordType>();
2324  const RecordDecl *RD = RT->getDecl();
2325 
2326  if (!RD->isCompleteDefinition())
2327  return B;
2328 
2329  // Handle lazy compound values and symbolic values.
2331  V.getAs<nonloc::LazyCompoundVal>()) {
2332  if (Optional<RegionBindingsRef> NewB = tryBindSmallStruct(B, R, RD, *LCV))
2333  return *NewB;
2334  return bindAggregate(B, R, V);
2335  }
2336  if (V.getAs<nonloc::SymbolVal>())
2337  return bindAggregate(B, R, V);
2338 
2339  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2340  // that we are binding symbolic struct value. Kill the field values, and if
2341  // the value is symbolic go and bind it as a "default" binding.
2342  if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>())
2343  return bindAggregate(B, R, UnknownVal());
2344 
2345  const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>();
2346  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2347 
2349  RegionBindingsRef NewB(B);
2350 
2351  for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
2352 
2353  if (VI == VE)
2354  break;
2355 
2356  // Skip any unnamed bitfields to stay in sync with the initializers.
2357  if (FI->isUnnamedBitfield())
2358  continue;
2359 
2360  QualType FTy = FI->getType();
2361  const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R);
2362 
2363  if (FTy->isArrayType())
2364  NewB = bindArray(NewB, FR, *VI);
2365  else if (FTy->isStructureOrClassType())
2366  NewB = bindStruct(NewB, FR, *VI);
2367  else
2368  NewB = bind(NewB, loc::MemRegionVal(FR), *VI);
2369  ++VI;
2370  }
2371 
2372  // There may be fewer values in the initialize list than the fields of struct.
2373  if (FI != FE) {
2374  NewB = NewB.addBinding(R, BindingKey::Default,
2375  svalBuilder.makeIntVal(0, false));
2376  }
2377 
2378  return NewB;
2379 }
2380 
2381 RegionBindingsRef
2382 RegionStoreManager::bindAggregate(RegionBindingsConstRef B,
2383  const TypedRegion *R,
2384  SVal Val) {
2385  // Remove the old bindings, using 'R' as the root of all regions
2386  // we will invalidate. Then add the new binding.
2387  return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val);
2388 }
2389 
2390 //===----------------------------------------------------------------------===//
2391 // State pruning.
2392 //===----------------------------------------------------------------------===//
2393 
2394 namespace {
2395 class RemoveDeadBindingsWorker
2396  : public ClusterAnalysis<RemoveDeadBindingsWorker> {
2397  using ChildrenListTy = SmallVector<const SymbolDerived *, 4>;
2398  using MapParentsToDerivedTy = llvm::DenseMap<SymbolRef, ChildrenListTy>;
2399 
2400  MapParentsToDerivedTy ParentsToDerived;
2401  SymbolReaper &SymReaper;
2402  const StackFrameContext *CurrentLCtx;
2403 
2404 public:
2405  RemoveDeadBindingsWorker(RegionStoreManager &rm,
2406  ProgramStateManager &stateMgr,
2407  RegionBindingsRef b, SymbolReaper &symReaper,
2408  const StackFrameContext *LCtx)
2409  : ClusterAnalysis<RemoveDeadBindingsWorker>(rm, stateMgr, b),
2410  SymReaper(symReaper), CurrentLCtx(LCtx) {}
2411 
2412  // Called by ClusterAnalysis.
2413  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C);
2414  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
2415  using ClusterAnalysis<RemoveDeadBindingsWorker>::VisitCluster;
2416 
2417  using ClusterAnalysis::AddToWorkList;
2418 
2419  bool AddToWorkList(const MemRegion *R);
2420 
2421  void VisitBinding(SVal V);
2422 
2423 private:
2424  void populateWorklistFromSymbol(SymbolRef s);
2425 };
2426 }
2427 
2428 bool RemoveDeadBindingsWorker::AddToWorkList(const MemRegion *R) {
2429  const MemRegion *BaseR = R->getBaseRegion();
2430  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
2431 }
2432 
2433 void RemoveDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
2434  const ClusterBindings &C) {
2435 
2436  if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) {
2437  if (SymReaper.isLive(VR))
2438  AddToWorkList(baseR, &C);
2439 
2440  return;
2441  }
2442 
2443  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) {
2444  if (SymReaper.isLive(SR->getSymbol())) {
2445  AddToWorkList(SR, &C);
2446  } else if (const auto *SD = dyn_cast<SymbolDerived>(SR->getSymbol())) {
2447  ParentsToDerived[SD->getParentSymbol()].push_back(SD);
2448  }
2449 
2450  return;
2451  }
2452 
2453  if (isa<NonStaticGlobalSpaceRegion>(baseR)) {
2454  AddToWorkList(baseR, &C);
2455  return;
2456  }
2457 
2458  // CXXThisRegion in the current or parent location context is live.
2459  if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) {
2460  const auto *StackReg =
2461  cast<StackArgumentsSpaceRegion>(TR->getSuperRegion());
2462  const StackFrameContext *RegCtx = StackReg->getStackFrame();
2463  if (CurrentLCtx &&
2464  (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx)))
2465  AddToWorkList(TR, &C);
2466  }
2467 }
2468 
2469 void RemoveDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
2470  const ClusterBindings *C) {
2471  if (!C)
2472  return;
2473 
2474  // Mark the symbol for any SymbolicRegion with live bindings as live itself.
2475  // This means we should continue to track that symbol.
2476  if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR))
2477  SymReaper.markLive(SymR->getSymbol());
2478 
2479  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) {
2480  // Element index of a binding key is live.
2481  SymReaper.markElementIndicesLive(I.getKey().getRegion());
2482 
2483  VisitBinding(I.getData());
2484  }
2485 }
2486 
2487 void RemoveDeadBindingsWorker::VisitBinding(SVal V) {
2488  // Is it a LazyCompoundVal? All referenced regions are live as well.
2490  V.getAs<nonloc::LazyCompoundVal>()) {
2491 
2492  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
2493 
2494  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
2495  E = Vals.end();
2496  I != E; ++I)
2497  VisitBinding(*I);
2498 
2499  return;
2500  }
2501 
2502  // If V is a region, then add it to the worklist.
2503  if (const MemRegion *R = V.getAsRegion()) {
2504  AddToWorkList(R);
2505 
2506  if (const auto *TVR = dyn_cast<TypedValueRegion>(R)) {
2507  DefinedOrUnknownSVal RVS =
2508  RM.getSValBuilder().getRegionValueSymbolVal(TVR);
2509  if (const MemRegion *SR = RVS.getAsRegion()) {
2510  AddToWorkList(SR);
2511  }
2512  }
2513 
2514  SymReaper.markLive(R);
2515 
2516  // All regions captured by a block are also live.
2517  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) {
2518  BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(),
2519  E = BR->referenced_vars_end();
2520  for ( ; I != E; ++I)
2521  AddToWorkList(I.getCapturedRegion());
2522  }
2523  }
2524 
2525 
2526  // Update the set of live symbols.
2527  for (auto SI = V.symbol_begin(), SE = V.symbol_end(); SI != SE; ++SI) {
2528  populateWorklistFromSymbol(*SI);
2529 
2530  for (const auto *SD : ParentsToDerived[*SI])
2531  populateWorklistFromSymbol(SD);
2532 
2533  SymReaper.markLive(*SI);
2534  }
2535 }
2536 
2537 void RemoveDeadBindingsWorker::populateWorklistFromSymbol(SymbolRef S) {
2538  if (const auto *SD = dyn_cast<SymbolData>(S)) {
2539  if (Loc::isLocType(SD->getType()) && !SymReaper.isLive(SD)) {
2540  const SymbolicRegion *SR = RM.getRegionManager().getSymbolicRegion(SD);
2541 
2542  if (B.contains(SR))
2543  AddToWorkList(SR);
2544 
2545  const SymbolicRegion *SHR =
2546  RM.getRegionManager().getSymbolicHeapRegion(SD);
2547  if (B.contains(SHR))
2548  AddToWorkList(SHR);
2549  }
2550  }
2551 }
2552 
2553 StoreRef RegionStoreManager::removeDeadBindings(Store store,
2554  const StackFrameContext *LCtx,
2555  SymbolReaper& SymReaper) {
2556  RegionBindingsRef B = getRegionBindings(store);
2557  RemoveDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
2558  W.GenerateClusters();
2559 
2560  // Enqueue the region roots onto the worklist.
2561  for (SymbolReaper::region_iterator I = SymReaper.region_begin(),
2562  E = SymReaper.region_end(); I != E; ++I) {
2563  W.AddToWorkList(*I);
2564  }
2565 
2566  W.RunWorkList();
2567 
2568  // We have now scanned the store, marking reachable regions and symbols
2569  // as live. We now remove all the regions that are dead from the store
2570  // as well as update DSymbols with the set symbols that are now dead.
2571  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
2572  const MemRegion *Base = I.getKey();
2573 
2574  // If the cluster has been visited, we know the region has been marked.
2575  if (W.isVisited(Base))
2576  continue;
2577 
2578  // Remove the dead entry.
2579  B = B.remove(Base);
2580 
2581  if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base))
2582  SymReaper.maybeDead(SymR->getSymbol());
2583 
2584  // Mark all non-live symbols that this binding references as dead.
2585  const ClusterBindings &Cluster = I.getData();
2586  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2587  CI != CE; ++CI) {
2588  SVal X = CI.getData();
2589  SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end();
2590  for (; SI != SE; ++SI)
2591  SymReaper.maybeDead(*SI);
2592  }
2593  }
2594 
2595  return StoreRef(B.asStore(), *this);
2596 }
2597 
2598 //===----------------------------------------------------------------------===//
2599 // Utility methods.
2600 //===----------------------------------------------------------------------===//
2601 
2602 void RegionStoreManager::print(Store store, raw_ostream &OS,
2603  const char* nl, const char *sep) {
2604  RegionBindingsRef B = getRegionBindings(store);
2605  OS << "Store (direct and default bindings), "
2606  << B.asStore()
2607  << " :" << nl;
2608  B.dump(OS, nl);
2609 }
A (possibly-)qualified type.
Definition: Type.h:642
bool isArrayType() const
Definition: Type.h:6226
static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields)
const internal::VariadicAllOfMatcher< Stmt > stmt
Matches statements.
bool operator==(CanQual< T > x, CanQual< U > y)
llvm::DenseSet< SymbolRef > InvalidatedSymbols
Definition: Store.h:52
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:30
const SymExpr * SymbolRef
internal::Matcher< Stmt > StatementMatcher
Definition: ASTMatchers.h:146
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:497
IntrusiveRefCntPtr< const ProgramState > ProgramStateRef
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:3775
const internal::ArgumentAdaptingMatcherFunc< internal::HasDescendantMatcher > hasDescendant
Matches AST nodes that have descendant AST nodes that match the provided matcher. ...
Represents an array type, per C99 6.7.5.2 - Array Declarators.
Definition: Type.h:2786
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.
QualType getElementType() const
Definition: Type.h:2821
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6590
const void * Store
Store - This opaque type encapsulates an immutable mapping from locations to values.
Definition: StoreRef.h:28
bool field_empty() const
Definition: Decl.h:3769
const internal::VariadicDynCastAllOfMatcher< Decl, VarDecl > varDecl
Matches variable declarations.
std::unique_ptr< StoreManager > CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr)
Represents a struct/union/class.
Definition: Decl.h:3570
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:154
llvm::ImmutableList< SVal >::iterator iterator
Definition: SVals.h:465
RecordDecl * getDefinition() const
Returns the RecordDecl that actually defines this struct/union/class.
Definition: Decl.h:3751
field_range fields() const
Definition: Decl.h:3761
Represents a member of a struct/union/class.
Definition: Decl.h:2556
static bool canSymbolicate(QualType T)
bool isReferenceType() const
Definition: Type.h:6189
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
bool isIntegralOrEnumerationType() const
Determine whether this type is an integral or enumeration type.
Definition: Type.h:6504
static bool isLocType(QualType T)
Definition: SVals.h:327
unsigned getLength() const
Definition: Expr.h:1649
const internal::VariadicDynCastAllOfMatcher< Stmt, DeclRefExpr > declRefExpr
Matches expressions that refer to declarations.
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
SmallVector< const MemRegion *, 8 > InvalidatedRegions
Definition: Store.h:210
bool isScalarType() const
Definition: Type.h:6489
SmallVector< BoundNodes, 1 > match(MatcherT Matcher, const NodeT &Node, ASTContext &Context)
Returns the results of matching Matcher on Node.
std::unique_ptr< StoreManager > CreateRegionStoreManager(ProgramStateManager &StMgr)
bool hasAttr() const
Definition: DeclBase.h:531
static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields)
When applied to a MemSpaceRegion, indicates the entire memory space should be invalidated.
Definition: MemRegion.h:1463
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.
This represents one expression.
Definition: Expr.h:105
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 T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6653
uint32_t getCodeUnit(size_t i) const
Definition: Expr.h:1638
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:3142
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:467
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:707
__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
bool isConstQualified() const
Determine whether this type is const-qualified.
Definition: Type.h:6012
bool isVoidPointerType() const
Definition: Type.cpp:461
Maps string IDs to AST nodes matched by parts of a matcher.
Definition: ASTMatchers.h:102
bool isStructureOrClassType() const
Definition: Type.cpp:453
Kind
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:2698
bool isAnyPointerType() const
Definition: Type.h:6181
bool operator<(DeclarationName LHS, DeclarationName RHS)
Ordering on two declaration names.
bool isVectorType() const
Definition: Type.h:6262
Tells that a region&#39;s contents is not changed.
Definition: MemRegion.h:1453
__PTRDIFF_TYPE__ ptrdiff_t
A signed integer type that is the result of subtracting two pointers.
Definition: opencl-c.h:68
Dataflow Directional Tag Classes.
raw_ostream & operator<<(raw_ostream &Out, const CheckerBase &Checker)
Dump checker name to stream.
Definition: Checker.cpp:34
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.
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:2017
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:4253
const StackFrameContext * getStackFrame() const
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:13824
static bool isUnionField(const FieldRegion *FR)
Represents a C++ struct/union/class.
Definition: DeclCXX.h:300
bool isVoidType() const
Definition: Type.h:6404
StringLiteral - This represents a string literal expression, e.g.
Definition: Expr.h:1568
Defines the clang::TargetInfo interface.
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
Represents the canonical version of C arrays with a specified constant size.
Definition: Type.h:2846