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) override;
605 
606  void iterBindings(Store store, BindingsHandler& f) override {
607  RegionBindingsRef B = getRegionBindings(store);
608  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
609  const ClusterBindings &Cluster = I.getData();
610  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
611  CI != CE; ++CI) {
612  const BindingKey &K = CI.getKey();
613  if (!K.isDirect())
614  continue;
615  if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) {
616  // FIXME: Possibly incorporate the offset?
617  if (!f.HandleBinding(*this, store, R, CI.getData()))
618  return;
619  }
620  }
621  }
622  }
623 };
624 
625 } // end anonymous namespace
626 
627 //===----------------------------------------------------------------------===//
628 // RegionStore creation.
629 //===----------------------------------------------------------------------===//
630 
631 std::unique_ptr<StoreManager>
633  RegionStoreFeatures F = maximal_features_tag();
634  return llvm::make_unique<RegionStoreManager>(StMgr, F);
635 }
636 
637 std::unique_ptr<StoreManager>
639  RegionStoreFeatures F = minimal_features_tag();
640  F.enableFields(true);
641  return llvm::make_unique<RegionStoreManager>(StMgr, F);
642 }
643 
644 
645 //===----------------------------------------------------------------------===//
646 // Region Cluster analysis.
647 //===----------------------------------------------------------------------===//
648 
649 namespace {
650 /// Used to determine which global regions are automatically included in the
651 /// initial worklist of a ClusterAnalysis.
653  /// Don't include any global regions.
654  GFK_None,
655  /// Only include system globals.
656  GFK_SystemOnly,
657  /// Include all global regions.
658  GFK_All
659 };
660 
661 template <typename DERIVED>
662 class ClusterAnalysis {
663 protected:
664  typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap;
665  typedef const MemRegion * WorkListElement;
666  typedef SmallVector<WorkListElement, 10> WorkList;
667 
668  llvm::SmallPtrSet<const ClusterBindings *, 16> Visited;
669 
670  WorkList WL;
671 
672  RegionStoreManager &RM;
673  ASTContext &Ctx;
674  SValBuilder &svalBuilder;
675 
676  RegionBindingsRef B;
677 
678 
679 protected:
680  const ClusterBindings *getCluster(const MemRegion *R) {
681  return B.lookup(R);
682  }
683 
684  /// Returns true if all clusters in the given memspace should be initially
685  /// included in the cluster analysis. Subclasses may provide their
686  /// own implementation.
687  bool includeEntireMemorySpace(const MemRegion *Base) {
688  return false;
689  }
690 
691 public:
692  ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr,
693  RegionBindingsRef b)
694  : RM(rm), Ctx(StateMgr.getContext()),
695  svalBuilder(StateMgr.getSValBuilder()), B(std::move(b)) {}
696 
697  RegionBindingsRef getRegionBindings() const { return B; }
698 
699  bool isVisited(const MemRegion *R) {
700  return Visited.count(getCluster(R));
701  }
702 
703  void GenerateClusters() {
704  // Scan the entire set of bindings and record the region clusters.
705  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end();
706  RI != RE; ++RI){
707  const MemRegion *Base = RI.getKey();
708 
709  const ClusterBindings &Cluster = RI.getData();
710  assert(!Cluster.isEmpty() && "Empty clusters should be removed");
711  static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster);
712 
713  // If the base's memspace should be entirely invalidated, add the cluster
714  // to the workspace up front.
715  if (static_cast<DERIVED*>(this)->includeEntireMemorySpace(Base))
716  AddToWorkList(WorkListElement(Base), &Cluster);
717  }
718  }
719 
720  bool AddToWorkList(WorkListElement E, const ClusterBindings *C) {
721  if (C && !Visited.insert(C).second)
722  return false;
723  WL.push_back(E);
724  return true;
725  }
726 
727  bool AddToWorkList(const MemRegion *R) {
728  return static_cast<DERIVED*>(this)->AddToWorkList(R);
729  }
730 
731  void RunWorkList() {
732  while (!WL.empty()) {
733  WorkListElement E = WL.pop_back_val();
734  const MemRegion *BaseR = E;
735 
736  static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR));
737  }
738  }
739 
740  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {}
741  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {}
742 
743  void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C,
744  bool Flag) {
745  static_cast<DERIVED*>(this)->VisitCluster(BaseR, C);
746  }
747 };
748 }
749 
750 //===----------------------------------------------------------------------===//
751 // Binding invalidation.
752 //===----------------------------------------------------------------------===//
753 
754 bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R,
755  ScanReachableSymbols &Callbacks) {
756  assert(R == R->getBaseRegion() && "Should only be called for base regions");
757  RegionBindingsRef B = getRegionBindings(S);
758  const ClusterBindings *Cluster = B.lookup(R);
759 
760  if (!Cluster)
761  return true;
762 
763  for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end();
764  RI != RE; ++RI) {
765  if (!Callbacks.scan(RI.getData()))
766  return false;
767  }
768 
769  return true;
770 }
771 
772 static inline bool isUnionField(const FieldRegion *FR) {
773  return FR->getDecl()->getParent()->isUnion();
774 }
775 
777 
778 static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) {
779  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
780 
781  const MemRegion *Base = K.getConcreteOffsetRegion();
782  const MemRegion *R = K.getRegion();
783 
784  while (R != Base) {
785  if (const FieldRegion *FR = dyn_cast<FieldRegion>(R))
786  if (!isUnionField(FR))
787  Fields.push_back(FR->getDecl());
788 
789  R = cast<SubRegion>(R)->getSuperRegion();
790  }
791 }
792 
793 static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) {
794  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
795 
796  if (Fields.empty())
797  return true;
798 
799  FieldVector FieldsInBindingKey;
800  getSymbolicOffsetFields(K, FieldsInBindingKey);
801 
802  ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size();
803  if (Delta >= 0)
804  return std::equal(FieldsInBindingKey.begin() + Delta,
805  FieldsInBindingKey.end(),
806  Fields.begin());
807  else
808  return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(),
809  Fields.begin() - Delta);
810 }
811 
812 /// Collects all bindings in \p Cluster that may refer to bindings within
813 /// \p Top.
814 ///
815 /// Each binding is a pair whose \c first is the key (a BindingKey) and whose
816 /// \c second is the value (an SVal).
817 ///
818 /// The \p IncludeAllDefaultBindings parameter specifies whether to include
819 /// default bindings that may extend beyond \p Top itself, e.g. if \p Top is
820 /// an aggregate within a larger aggregate with a default binding.
821 static void
823  SValBuilder &SVB, const ClusterBindings &Cluster,
824  const SubRegion *Top, BindingKey TopKey,
825  bool IncludeAllDefaultBindings) {
826  FieldVector FieldsInSymbolicSubregions;
827  if (TopKey.hasSymbolicOffset()) {
828  getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions);
829  Top = TopKey.getConcreteOffsetRegion();
830  TopKey = BindingKey::Make(Top, BindingKey::Default);
831  }
832 
833  // Find the length (in bits) of the region being invalidated.
834  uint64_t Length = UINT64_MAX;
835  SVal Extent = Top->getExtent(SVB);
836  if (Optional<nonloc::ConcreteInt> ExtentCI =
837  Extent.getAs<nonloc::ConcreteInt>()) {
838  const llvm::APSInt &ExtentInt = ExtentCI->getValue();
839  assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned());
840  // Extents are in bytes but region offsets are in bits. Be careful!
841  Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth();
842  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) {
843  if (FR->getDecl()->isBitField())
844  Length = FR->getDecl()->getBitWidthValue(SVB.getContext());
845  }
846 
847  for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end();
848  I != E; ++I) {
849  BindingKey NextKey = I.getKey();
850  if (NextKey.getRegion() == TopKey.getRegion()) {
851  // FIXME: This doesn't catch the case where we're really invalidating a
852  // region with a symbolic offset. Example:
853  // R: points[i].y
854  // Next: points[0].x
855 
856  if (NextKey.getOffset() > TopKey.getOffset() &&
857  NextKey.getOffset() - TopKey.getOffset() < Length) {
858  // Case 1: The next binding is inside the region we're invalidating.
859  // Include it.
860  Bindings.push_back(*I);
861 
862  } else if (NextKey.getOffset() == TopKey.getOffset()) {
863  // Case 2: The next binding is at the same offset as the region we're
864  // invalidating. In this case, we need to leave default bindings alone,
865  // since they may be providing a default value for a regions beyond what
866  // we're invalidating.
867  // FIXME: This is probably incorrect; consider invalidating an outer
868  // struct whose first field is bound to a LazyCompoundVal.
869  if (IncludeAllDefaultBindings || NextKey.isDirect())
870  Bindings.push_back(*I);
871  }
872 
873  } else if (NextKey.hasSymbolicOffset()) {
874  const MemRegion *Base = NextKey.getConcreteOffsetRegion();
875  if (Top->isSubRegionOf(Base) && Top != Base) {
876  // Case 3: The next key is symbolic and we just changed something within
877  // its concrete region. We don't know if the binding is still valid, so
878  // we'll be conservative and include it.
879  if (IncludeAllDefaultBindings || NextKey.isDirect())
880  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
881  Bindings.push_back(*I);
882  } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) {
883  // Case 4: The next key is symbolic, but we changed a known
884  // super-region. In this case the binding is certainly included.
885  if (BaseSR->isSubRegionOf(Top))
886  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
887  Bindings.push_back(*I);
888  }
889  }
890  }
891 }
892 
893 static void
895  SValBuilder &SVB, const ClusterBindings &Cluster,
896  const SubRegion *Top, bool IncludeAllDefaultBindings) {
897  collectSubRegionBindings(Bindings, SVB, Cluster, Top,
899  IncludeAllDefaultBindings);
900 }
901 
902 RegionBindingsRef
903 RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B,
904  const SubRegion *Top) {
905  BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default);
906  const MemRegion *ClusterHead = TopKey.getBaseRegion();
907 
908  if (Top == ClusterHead) {
909  // We can remove an entire cluster's bindings all in one go.
910  return B.remove(Top);
911  }
912 
913  const ClusterBindings *Cluster = B.lookup(ClusterHead);
914  if (!Cluster) {
915  // If we're invalidating a region with a symbolic offset, we need to make
916  // sure we don't treat the base region as uninitialized anymore.
917  if (TopKey.hasSymbolicOffset()) {
918  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
919  return B.addBinding(Concrete, BindingKey::Default, UnknownVal());
920  }
921  return B;
922  }
923 
925  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey,
926  /*IncludeAllDefaultBindings=*/false);
927 
928  ClusterBindingsRef Result(*Cluster, CBFactory);
929  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
930  E = Bindings.end();
931  I != E; ++I)
932  Result = Result.remove(I->first);
933 
934  // If we're invalidating a region with a symbolic offset, we need to make sure
935  // we don't treat the base region as uninitialized anymore.
936  // FIXME: This isn't very precise; see the example in
937  // collectSubRegionBindings.
938  if (TopKey.hasSymbolicOffset()) {
939  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
940  Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default),
941  UnknownVal());
942  }
943 
944  if (Result.isEmpty())
945  return B.remove(ClusterHead);
946  return B.add(ClusterHead, Result.asImmutableMap());
947 }
948 
949 namespace {
950 class InvalidateRegionsWorker : public ClusterAnalysis<InvalidateRegionsWorker>
951 {
952  const Expr *Ex;
953  unsigned Count;
954  const LocationContext *LCtx;
955  InvalidatedSymbols &IS;
956  RegionAndSymbolInvalidationTraits &ITraits;
958  GlobalsFilterKind GlobalsFilter;
959 public:
960  InvalidateRegionsWorker(RegionStoreManager &rm,
961  ProgramStateManager &stateMgr,
962  RegionBindingsRef b,
963  const Expr *ex, unsigned count,
964  const LocationContext *lctx,
965  InvalidatedSymbols &is,
966  RegionAndSymbolInvalidationTraits &ITraitsIn,
968  GlobalsFilterKind GFK)
969  : ClusterAnalysis<InvalidateRegionsWorker>(rm, stateMgr, b),
970  Ex(ex), Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r),
971  GlobalsFilter(GFK) {}
972 
973  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
974  void VisitBinding(SVal V);
975 
976  using ClusterAnalysis::AddToWorkList;
977 
978  bool AddToWorkList(const MemRegion *R);
979 
980  /// Returns true if all clusters in the memory space for \p Base should be
981  /// be invalidated.
982  bool includeEntireMemorySpace(const MemRegion *Base);
983 
984  /// Returns true if the memory space of the given region is one of the global
985  /// regions specially included at the start of invalidation.
986  bool isInitiallyIncludedGlobalRegion(const MemRegion *R);
987 };
988 }
989 
990 bool InvalidateRegionsWorker::AddToWorkList(const MemRegion *R) {
991  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
993  const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion();
994  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
995 }
996 
997 void InvalidateRegionsWorker::VisitBinding(SVal V) {
998  // A symbol? Mark it touched by the invalidation.
999  if (SymbolRef Sym = V.getAsSymbol())
1000  IS.insert(Sym);
1001 
1002  if (const MemRegion *R = V.getAsRegion()) {
1003  AddToWorkList(R);
1004  return;
1005  }
1006 
1007  // Is it a LazyCompoundVal? All references get invalidated as well.
1009  V.getAs<nonloc::LazyCompoundVal>()) {
1010 
1011  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
1012 
1013  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
1014  E = Vals.end();
1015  I != E; ++I)
1016  VisitBinding(*I);
1017 
1018  return;
1019  }
1020 }
1021 
1022 void InvalidateRegionsWorker::VisitCluster(const MemRegion *baseR,
1023  const ClusterBindings *C) {
1024 
1025  bool PreserveRegionsContents =
1026  ITraits.hasTrait(baseR,
1028 
1029  if (C) {
1030  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I)
1031  VisitBinding(I.getData());
1032 
1033  // Invalidate regions contents.
1034  if (!PreserveRegionsContents)
1035  B = B.remove(baseR);
1036  }
1037 
1038  if (const auto *TO = dyn_cast<TypedValueRegion>(baseR)) {
1039  if (const auto *RD = TO->getValueType()->getAsCXXRecordDecl()) {
1040 
1041  // Lambdas can affect all static local variables without explicitly
1042  // capturing those.
1043  // We invalidate all static locals referenced inside the lambda body.
1044  if (RD->isLambda() && RD->getLambdaCallOperator()->getBody()) {
1045  using namespace ast_matchers;
1046 
1047  const char *DeclBind = "DeclBind";
1049  to(varDecl(hasStaticStorageDuration()).bind(DeclBind)))));
1050  auto Matches =
1051  match(RefToStatic, *RD->getLambdaCallOperator()->getBody(),
1052  RD->getASTContext());
1053 
1054  for (BoundNodes &Match : Matches) {
1055  auto *VD = Match.getNodeAs<VarDecl>(DeclBind);
1056  const VarRegion *ToInvalidate =
1057  RM.getRegionManager().getVarRegion(VD, LCtx);
1058  AddToWorkList(ToInvalidate);
1059  }
1060  }
1061  }
1062  }
1063 
1064  // BlockDataRegion? If so, invalidate captured variables that are passed
1065  // by reference.
1066  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) {
1067  for (BlockDataRegion::referenced_vars_iterator
1068  BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ;
1069  BI != BE; ++BI) {
1070  const VarRegion *VR = BI.getCapturedRegion();
1071  const VarDecl *VD = VR->getDecl();
1072  if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage()) {
1073  AddToWorkList(VR);
1074  }
1075  else if (Loc::isLocType(VR->getValueType())) {
1076  // Map the current bindings to a Store to retrieve the value
1077  // of the binding. If that binding itself is a region, we should
1078  // invalidate that region. This is because a block may capture
1079  // a pointer value, but the thing pointed by that pointer may
1080  // get invalidated.
1081  SVal V = RM.getBinding(B, loc::MemRegionVal(VR));
1082  if (Optional<Loc> L = V.getAs<Loc>()) {
1083  if (const MemRegion *LR = L->getAsRegion())
1084  AddToWorkList(LR);
1085  }
1086  }
1087  }
1088  return;
1089  }
1090 
1091  // Symbolic region?
1092  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR))
1093  IS.insert(SR->getSymbol());
1094 
1095  // Nothing else should be done in the case when we preserve regions context.
1096  if (PreserveRegionsContents)
1097  return;
1098 
1099  // Otherwise, we have a normal data region. Record that we touched the region.
1100  if (Regions)
1101  Regions->push_back(baseR);
1102 
1103  if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) {
1104  // Invalidate the region by setting its default value to
1105  // conjured symbol. The type of the symbol is irrelevant.
1106  DefinedOrUnknownSVal V =
1107  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
1108  B = B.addBinding(baseR, BindingKey::Default, V);
1109  return;
1110  }
1111 
1112  if (!baseR->isBoundable())
1113  return;
1114 
1115  const TypedValueRegion *TR = cast<TypedValueRegion>(baseR);
1116  QualType T = TR->getValueType();
1117 
1118  if (isInitiallyIncludedGlobalRegion(baseR)) {
1119  // If the region is a global and we are invalidating all globals,
1120  // erasing the entry is good enough. This causes all globals to be lazily
1121  // symbolicated from the same base symbol.
1122  return;
1123  }
1124 
1125  if (T->isRecordType()) {
1126  // Invalidate the region by setting its default value to
1127  // conjured symbol. The type of the symbol is irrelevant.
1128  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1129  Ctx.IntTy, Count);
1130  B = B.addBinding(baseR, BindingKey::Default, V);
1131  return;
1132  }
1133 
1134  if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
1135  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1136  baseR,
1138 
1139  if (doNotInvalidateSuperRegion) {
1140  // We are not doing blank invalidation of the whole array region so we
1141  // have to manually invalidate each elements.
1142  Optional<uint64_t> NumElements;
1143 
1144  // Compute lower and upper offsets for region within array.
1145  if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT))
1146  NumElements = CAT->getSize().getZExtValue();
1147  if (!NumElements) // We are not dealing with a constant size array
1148  goto conjure_default;
1149  QualType ElementTy = AT->getElementType();
1150  uint64_t ElemSize = Ctx.getTypeSize(ElementTy);
1151  const RegionOffset &RO = baseR->getAsOffset();
1152  const MemRegion *SuperR = baseR->getBaseRegion();
1153  if (RO.hasSymbolicOffset()) {
1154  // If base region has a symbolic offset,
1155  // we revert to invalidating the super region.
1156  if (SuperR)
1157  AddToWorkList(SuperR);
1158  goto conjure_default;
1159  }
1160 
1161  uint64_t LowerOffset = RO.getOffset();
1162  uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize;
1163  bool UpperOverflow = UpperOffset < LowerOffset;
1164 
1165  // Invalidate regions which are within array boundaries,
1166  // or have a symbolic offset.
1167  if (!SuperR)
1168  goto conjure_default;
1169 
1170  const ClusterBindings *C = B.lookup(SuperR);
1171  if (!C)
1172  goto conjure_default;
1173 
1174  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E;
1175  ++I) {
1176  const BindingKey &BK = I.getKey();
1177  Optional<uint64_t> ROffset =
1178  BK.hasSymbolicOffset() ? Optional<uint64_t>() : BK.getOffset();
1179 
1180  // Check offset is not symbolic and within array's boundaries.
1181  // Handles arrays of 0 elements and of 0-sized elements as well.
1182  if (!ROffset ||
1183  ((*ROffset >= LowerOffset && *ROffset < UpperOffset) ||
1184  (UpperOverflow &&
1185  (*ROffset >= LowerOffset || *ROffset < UpperOffset)) ||
1186  (LowerOffset == UpperOffset && *ROffset == LowerOffset))) {
1187  B = B.removeBinding(I.getKey());
1188  // Bound symbolic regions need to be invalidated for dead symbol
1189  // detection.
1190  SVal V = I.getData();
1191  const MemRegion *R = V.getAsRegion();
1192  if (R && isa<SymbolicRegion>(R))
1193  VisitBinding(V);
1194  }
1195  }
1196  }
1197  conjure_default:
1198  // Set the default value of the array to conjured symbol.
1199  DefinedOrUnknownSVal V =
1200  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1201  AT->getElementType(), Count);
1202  B = B.addBinding(baseR, BindingKey::Default, V);
1203  return;
1204  }
1205 
1206  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1207  T,Count);
1208  assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
1209  B = B.addBinding(baseR, BindingKey::Direct, V);
1210 }
1211 
1212 bool InvalidateRegionsWorker::isInitiallyIncludedGlobalRegion(
1213  const MemRegion *R) {
1214  switch (GlobalsFilter) {
1215  case GFK_None:
1216  return false;
1217  case GFK_SystemOnly:
1218  return isa<GlobalSystemSpaceRegion>(R->getMemorySpace());
1219  case GFK_All:
1220  return isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace());
1221  }
1222 
1223  llvm_unreachable("unknown globals filter");
1224 }
1225 
1226 bool InvalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) {
1227  if (isInitiallyIncludedGlobalRegion(Base))
1228  return true;
1229 
1230  const MemSpaceRegion *MemSpace = Base->getMemorySpace();
1231  return ITraits.hasTrait(MemSpace,
1233 }
1234 
1235 RegionBindingsRef
1236 RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K,
1237  const Expr *Ex,
1238  unsigned Count,
1239  const LocationContext *LCtx,
1240  RegionBindingsRef B,
1241  InvalidatedRegions *Invalidated) {
1242  // Bind the globals memory space to a new symbol that we will use to derive
1243  // the bindings for all globals.
1244  const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K);
1245  SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx,
1246  /* type does not matter */ Ctx.IntTy,
1247  Count);
1248 
1249  B = B.removeBinding(GS)
1250  .addBinding(BindingKey::Make(GS, BindingKey::Default), V);
1251 
1252  // Even if there are no bindings in the global scope, we still need to
1253  // record that we touched it.
1254  if (Invalidated)
1255  Invalidated->push_back(GS);
1256 
1257  return B;
1258 }
1259 
1260 void RegionStoreManager::populateWorkList(InvalidateRegionsWorker &W,
1261  ArrayRef<SVal> Values,
1262  InvalidatedRegions *TopLevelRegions) {
1263  for (ArrayRef<SVal>::iterator I = Values.begin(),
1264  E = Values.end(); I != E; ++I) {
1265  SVal V = *I;
1267  V.getAs<nonloc::LazyCompoundVal>()) {
1268 
1269  const SValListTy &Vals = getInterestingValues(*LCS);
1270 
1271  for (SValListTy::const_iterator I = Vals.begin(),
1272  E = Vals.end(); I != E; ++I) {
1273  // Note: the last argument is false here because these are
1274  // non-top-level regions.
1275  if (const MemRegion *R = (*I).getAsRegion())
1276  W.AddToWorkList(R);
1277  }
1278  continue;
1279  }
1280 
1281  if (const MemRegion *R = V.getAsRegion()) {
1282  if (TopLevelRegions)
1283  TopLevelRegions->push_back(R);
1284  W.AddToWorkList(R);
1285  continue;
1286  }
1287  }
1288 }
1289 
1290 StoreRef
1291 RegionStoreManager::invalidateRegions(Store store,
1292  ArrayRef<SVal> Values,
1293  const Expr *Ex, unsigned Count,
1294  const LocationContext *LCtx,
1295  const CallEvent *Call,
1296  InvalidatedSymbols &IS,
1297  RegionAndSymbolInvalidationTraits &ITraits,
1298  InvalidatedRegions *TopLevelRegions,
1299  InvalidatedRegions *Invalidated) {
1300  GlobalsFilterKind GlobalsFilter;
1301  if (Call) {
1302  if (Call->isInSystemHeader())
1303  GlobalsFilter = GFK_SystemOnly;
1304  else
1305  GlobalsFilter = GFK_All;
1306  } else {
1307  GlobalsFilter = GFK_None;
1308  }
1309 
1310  RegionBindingsRef B = getRegionBindings(store);
1311  InvalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, ITraits,
1312  Invalidated, GlobalsFilter);
1313 
1314  // Scan the bindings and generate the clusters.
1315  W.GenerateClusters();
1316 
1317  // Add the regions to the worklist.
1318  populateWorkList(W, Values, TopLevelRegions);
1319 
1320  W.RunWorkList();
1321 
1322  // Return the new bindings.
1323  B = W.getRegionBindings();
1324 
1325  // For calls, determine which global regions should be invalidated and
1326  // invalidate them. (Note that function-static and immutable globals are never
1327  // invalidated by this.)
1328  // TODO: This could possibly be more precise with modules.
1329  switch (GlobalsFilter) {
1330  case GFK_All:
1331  B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind,
1332  Ex, Count, LCtx, B, Invalidated);
1333  // FALLTHROUGH
1334  case GFK_SystemOnly:
1335  B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
1336  Ex, Count, LCtx, B, Invalidated);
1337  // FALLTHROUGH
1338  case GFK_None:
1339  break;
1340  }
1341 
1342  return StoreRef(B.asStore(), *this);
1343 }
1344 
1345 //===----------------------------------------------------------------------===//
1346 // Extents for regions.
1347 //===----------------------------------------------------------------------===//
1348 
1349 DefinedOrUnknownSVal
1350 RegionStoreManager::getSizeInElements(ProgramStateRef state,
1351  const MemRegion *R,
1352  QualType EleTy) {
1353  SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder);
1354  const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size);
1355  if (!SizeInt)
1356  return UnknownVal();
1357 
1358  CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue());
1359 
1360  if (Ctx.getAsVariableArrayType(EleTy)) {
1361  // FIXME: We need to track extra state to properly record the size
1362  // of VLAs. Returning UnknownVal here, however, is a stop-gap so that
1363  // we don't have a divide-by-zero below.
1364  return UnknownVal();
1365  }
1366 
1367  CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy);
1368 
1369  // If a variable is reinterpreted as a type that doesn't fit into a larger
1370  // type evenly, round it down.
1371  // This is a signed value, since it's used in arithmetic with signed indices.
1372  return svalBuilder.makeIntVal(RegionSize / EleSize,
1373  svalBuilder.getArrayIndexType());
1374 }
1375 
1376 //===----------------------------------------------------------------------===//
1377 // Location and region casting.
1378 //===----------------------------------------------------------------------===//
1379 
1380 /// ArrayToPointer - Emulates the "decay" of an array to a pointer
1381 /// type. 'Array' represents the lvalue of the array being decayed
1382 /// to a pointer, and the returned SVal represents the decayed
1383 /// version of that lvalue (i.e., a pointer to the first element of
1384 /// the array). This is called by ExprEngine when evaluating casts
1385 /// from arrays to pointers.
1386 SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) {
1387  if (Array.getAs<loc::ConcreteInt>())
1388  return Array;
1389 
1390  if (!Array.getAs<loc::MemRegionVal>())
1391  return UnknownVal();
1392 
1393  const SubRegion *R =
1394  cast<SubRegion>(Array.castAs<loc::MemRegionVal>().getRegion());
1395  NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
1396  return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, R, Ctx));
1397 }
1398 
1399 //===----------------------------------------------------------------------===//
1400 // Loading values from regions.
1401 //===----------------------------------------------------------------------===//
1402 
1403 SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) {
1404  assert(!L.getAs<UnknownVal>() && "location unknown");
1405  assert(!L.getAs<UndefinedVal>() && "location undefined");
1406 
1407  // For access to concrete addresses, return UnknownVal. Checks
1408  // for null dereferences (and similar errors) are done by checkers, not
1409  // the Store.
1410  // FIXME: We can consider lazily symbolicating such memory, but we really
1411  // should defer this when we can reason easily about symbolicating arrays
1412  // of bytes.
1413  if (L.getAs<loc::ConcreteInt>()) {
1414  return UnknownVal();
1415  }
1416  if (!L.getAs<loc::MemRegionVal>()) {
1417  return UnknownVal();
1418  }
1419 
1420  const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion();
1421 
1422  if (isa<BlockDataRegion>(MR)) {
1423  return UnknownVal();
1424  }
1425 
1426  if (!isa<TypedValueRegion>(MR)) {
1427  if (T.isNull()) {
1428  if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
1429  T = TR->getLocationType()->getPointeeType();
1430  else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1431  T = SR->getSymbol()->getType()->getPointeeType();
1432  }
1433  assert(!T.isNull() && "Unable to auto-detect binding type!");
1434  assert(!T->isVoidType() && "Attempting to dereference a void pointer!");
1435  MR = GetElementZeroRegion(cast<SubRegion>(MR), T);
1436  } else {
1437  T = cast<TypedValueRegion>(MR)->getValueType();
1438  }
1439 
1440  // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
1441  // instead of 'Loc', and have the other Loc cases handled at a higher level.
1442  const TypedValueRegion *R = cast<TypedValueRegion>(MR);
1443  QualType RTy = R->getValueType();
1444 
1445  // FIXME: we do not yet model the parts of a complex type, so treat the
1446  // whole thing as "unknown".
1447  if (RTy->isAnyComplexType())
1448  return UnknownVal();
1449 
1450  // FIXME: We should eventually handle funny addressing. e.g.:
1451  //
1452  // int x = ...;
1453  // int *p = &x;
1454  // char *q = (char*) p;
1455  // char c = *q; // returns the first byte of 'x'.
1456  //
1457  // Such funny addressing will occur due to layering of regions.
1458  if (RTy->isStructureOrClassType())
1459  return getBindingForStruct(B, R);
1460 
1461  // FIXME: Handle unions.
1462  if (RTy->isUnionType())
1463  return createLazyBinding(B, R);
1464 
1465  if (RTy->isArrayType()) {
1466  if (RTy->isConstantArrayType())
1467  return getBindingForArray(B, R);
1468  else
1469  return UnknownVal();
1470  }
1471 
1472  // FIXME: handle Vector types.
1473  if (RTy->isVectorType())
1474  return UnknownVal();
1475 
1476  if (const FieldRegion* FR = dyn_cast<FieldRegion>(R))
1477  return CastRetrievedVal(getBindingForField(B, FR), FR, T);
1478 
1479  if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
1480  // FIXME: Here we actually perform an implicit conversion from the loaded
1481  // value to the element type. Eventually we want to compose these values
1482  // more intelligently. For example, an 'element' can encompass multiple
1483  // bound regions (e.g., several bound bytes), or could be a subset of
1484  // a larger value.
1485  return CastRetrievedVal(getBindingForElement(B, ER), ER, T);
1486  }
1487 
1488  if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) {
1489  // FIXME: Here we actually perform an implicit conversion from the loaded
1490  // value to the ivar type. What we should model is stores to ivars
1491  // that blow past the extent of the ivar. If the address of the ivar is
1492  // reinterpretted, it is possible we stored a different value that could
1493  // fit within the ivar. Either we need to cast these when storing them
1494  // or reinterpret them lazily (as we do here).
1495  return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T);
1496  }
1497 
1498  if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
1499  // FIXME: Here we actually perform an implicit conversion from the loaded
1500  // value to the variable type. What we should model is stores to variables
1501  // that blow past the extent of the variable. If the address of the
1502  // variable is reinterpretted, it is possible we stored a different value
1503  // that could fit within the variable. Either we need to cast these when
1504  // storing them or reinterpret them lazily (as we do here).
1505  return CastRetrievedVal(getBindingForVar(B, VR), VR, T);
1506  }
1507 
1508  const SVal *V = B.lookup(R, BindingKey::Direct);
1509 
1510  // Check if the region has a binding.
1511  if (V)
1512  return *V;
1513 
1514  // The location does not have a bound value. This means that it has
1515  // the value it had upon its creation and/or entry to the analyzed
1516  // function/method. These are either symbolic values or 'undefined'.
1517  if (R->hasStackNonParametersStorage()) {
1518  // All stack variables are considered to have undefined values
1519  // upon creation. All heap allocated blocks are considered to
1520  // have undefined values as well unless they are explicitly bound
1521  // to specific values.
1522  return UndefinedVal();
1523  }
1524 
1525  // All other values are symbolic.
1526  return svalBuilder.getRegionValueSymbolVal(R);
1527 }
1528 
1529 static QualType getUnderlyingType(const SubRegion *R) {
1530  QualType RegionTy;
1531  if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R))
1532  RegionTy = TVR->getValueType();
1533 
1534  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1535  RegionTy = SR->getSymbol()->getType();
1536 
1537  return RegionTy;
1538 }
1539 
1540 /// Checks to see if store \p B has a lazy binding for region \p R.
1541 ///
1542 /// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected
1543 /// if there are additional bindings within \p R.
1544 ///
1545 /// Note that unlike RegionStoreManager::findLazyBinding, this will not search
1546 /// for lazy bindings for super-regions of \p R.
1548 getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B,
1549  const SubRegion *R, bool AllowSubregionBindings) {
1550  Optional<SVal> V = B.getDefaultBinding(R);
1551  if (!V)
1552  return None;
1553 
1554  Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>();
1555  if (!LCV)
1556  return None;
1557 
1558  // If the LCV is for a subregion, the types might not match, and we shouldn't
1559  // reuse the binding.
1560  QualType RegionTy = getUnderlyingType(R);
1561  if (!RegionTy.isNull() &&
1562  !RegionTy->isVoidPointerType()) {
1563  QualType SourceRegionTy = LCV->getRegion()->getValueType();
1564  if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy))
1565  return None;
1566  }
1567 
1568  if (!AllowSubregionBindings) {
1569  // If there are any other bindings within this region, we shouldn't reuse
1570  // the top-level binding.
1572  collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R,
1573  /*IncludeAllDefaultBindings=*/true);
1574  if (Bindings.size() > 1)
1575  return None;
1576  }
1577 
1578  return *LCV;
1579 }
1580 
1581 
1582 std::pair<Store, const SubRegion *>
1583 RegionStoreManager::findLazyBinding(RegionBindingsConstRef B,
1584  const SubRegion *R,
1585  const SubRegion *originalRegion) {
1586  if (originalRegion != R) {
1588  getExistingLazyBinding(svalBuilder, B, R, true))
1589  return std::make_pair(V->getStore(), V->getRegion());
1590  }
1591 
1592  typedef std::pair<Store, const SubRegion *> StoreRegionPair;
1593  StoreRegionPair Result = StoreRegionPair();
1594 
1595  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
1596  Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()),
1597  originalRegion);
1598 
1599  if (Result.second)
1600  Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second);
1601 
1602  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
1603  Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()),
1604  originalRegion);
1605 
1606  if (Result.second)
1607  Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second);
1608 
1609  } else if (const CXXBaseObjectRegion *BaseReg =
1610  dyn_cast<CXXBaseObjectRegion>(R)) {
1611  // C++ base object region is another kind of region that we should blast
1612  // through to look for lazy compound value. It is like a field region.
1613  Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()),
1614  originalRegion);
1615 
1616  if (Result.second)
1617  Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg,
1618  Result.second);
1619  }
1620 
1621  return Result;
1622 }
1623 
1624 SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B,
1625  const ElementRegion* R) {
1626  // We do not currently model bindings of the CompoundLiteralregion.
1627  if (isa<CompoundLiteralRegion>(R->getBaseRegion()))
1628  return UnknownVal();
1629 
1630  // Check if the region has a binding.
1631  if (const Optional<SVal> &V = B.getDirectBinding(R))
1632  return *V;
1633 
1634  const MemRegion* superR = R->getSuperRegion();
1635 
1636  // Check if the region is an element region of a string literal.
1637  if (const StringRegion *StrR = dyn_cast<StringRegion>(superR)) {
1638  // FIXME: Handle loads from strings where the literal is treated as
1639  // an integer, e.g., *((unsigned int*)"hello")
1640  QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType();
1641  if (!Ctx.hasSameUnqualifiedType(T, R->getElementType()))
1642  return UnknownVal();
1643 
1644  const StringLiteral *Str = StrR->getStringLiteral();
1645  SVal Idx = R->getIndex();
1646  if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) {
1647  int64_t i = CI->getValue().getSExtValue();
1648  // Abort on string underrun. This can be possible by arbitrary
1649  // clients of getBindingForElement().
1650  if (i < 0)
1651  return UndefinedVal();
1652  int64_t length = Str->getLength();
1653  // Technically, only i == length is guaranteed to be null.
1654  // However, such overflows should be caught before reaching this point;
1655  // the only time such an access would be made is if a string literal was
1656  // used to initialize a larger array.
1657  char c = (i >= length) ? '\0' : Str->getCodeUnit(i);
1658  return svalBuilder.makeIntVal(c, T);
1659  }
1660  } else if (const VarRegion *VR = dyn_cast<VarRegion>(superR)) {
1661  // Check if the containing array is const and has an initialized value.
1662  const VarDecl *VD = VR->getDecl();
1663  // Either the array or the array element has to be const.
1664  if (VD->getType().isConstQualified() || R->getElementType().isConstQualified()) {
1665  if (const Expr *Init = VD->getInit()) {
1666  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1667  // The array index has to be known.
1668  if (auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) {
1669  int64_t i = CI->getValue().getSExtValue();
1670  // If it is known that the index is out of bounds, we can return
1671  // an undefined value.
1672  if (i < 0)
1673  return UndefinedVal();
1674 
1675  if (auto CAT = Ctx.getAsConstantArrayType(VD->getType()))
1676  if (CAT->getSize().sle(i))
1677  return UndefinedVal();
1678 
1679  // If there is a list, but no init, it must be zero.
1680  if (i >= InitList->getNumInits())
1681  return svalBuilder.makeZeroVal(R->getElementType());
1682 
1683  if (const Expr *ElemInit = InitList->getInit(i))
1684  if (Optional<SVal> V = svalBuilder.getConstantVal(ElemInit))
1685  return *V;
1686  }
1687  }
1688  }
1689  }
1690  }
1691 
1692  // Check for loads from a code text region. For such loads, just give up.
1693  if (isa<CodeTextRegion>(superR))
1694  return UnknownVal();
1695 
1696  // Handle the case where we are indexing into a larger scalar object.
1697  // For example, this handles:
1698  // int x = ...
1699  // char *y = &x;
1700  // return *y;
1701  // FIXME: This is a hack, and doesn't do anything really intelligent yet.
1702  const RegionRawOffset &O = R->getAsArrayOffset();
1703 
1704  // If we cannot reason about the offset, return an unknown value.
1705  if (!O.getRegion())
1706  return UnknownVal();
1707 
1708  if (const TypedValueRegion *baseR =
1709  dyn_cast_or_null<TypedValueRegion>(O.getRegion())) {
1710  QualType baseT = baseR->getValueType();
1711  if (baseT->isScalarType()) {
1712  QualType elemT = R->getElementType();
1713  if (elemT->isScalarType()) {
1714  if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) {
1715  if (const Optional<SVal> &V = B.getDirectBinding(superR)) {
1716  if (SymbolRef parentSym = V->getAsSymbol())
1717  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1718 
1719  if (V->isUnknownOrUndef())
1720  return *V;
1721  // Other cases: give up. We are indexing into a larger object
1722  // that has some value, but we don't know how to handle that yet.
1723  return UnknownVal();
1724  }
1725  }
1726  }
1727  }
1728  }
1729  return getBindingForFieldOrElementCommon(B, R, R->getElementType());
1730 }
1731 
1732 SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B,
1733  const FieldRegion* R) {
1734 
1735  // Check if the region has a binding.
1736  if (const Optional<SVal> &V = B.getDirectBinding(R))
1737  return *V;
1738 
1739  // Is the field declared constant and has an in-class initializer?
1740  const FieldDecl *FD = R->getDecl();
1741  QualType Ty = FD->getType();
1742  if (Ty.isConstQualified())
1743  if (const Expr *Init = FD->getInClassInitializer())
1744  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1745  return *V;
1746 
1747  // If the containing record was initialized, try to get its constant value.
1748  const MemRegion* superR = R->getSuperRegion();
1749  if (const auto *VR = dyn_cast<VarRegion>(superR)) {
1750  const VarDecl *VD = VR->getDecl();
1751  QualType RecordVarTy = VD->getType();
1752  unsigned Index = FD->getFieldIndex();
1753  // Either the record variable or the field has to be const qualified.
1754  if (RecordVarTy.isConstQualified() || Ty.isConstQualified())
1755  if (const Expr *Init = VD->getInit())
1756  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1757  if (Index < InitList->getNumInits()) {
1758  if (const Expr *FieldInit = InitList->getInit(Index))
1759  if (Optional<SVal> V = svalBuilder.getConstantVal(FieldInit))
1760  return *V;
1761  } else {
1762  return svalBuilder.makeZeroVal(Ty);
1763  }
1764  }
1765  }
1766 
1767  return getBindingForFieldOrElementCommon(B, R, Ty);
1768 }
1769 
1771 RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
1772  const MemRegion *superR,
1773  const TypedValueRegion *R,
1774  QualType Ty) {
1775 
1776  if (const Optional<SVal> &D = B.getDefaultBinding(superR)) {
1777  const SVal &val = D.getValue();
1778  if (SymbolRef parentSym = val.getAsSymbol())
1779  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1780 
1781  if (val.isZeroConstant())
1782  return svalBuilder.makeZeroVal(Ty);
1783 
1784  if (val.isUnknownOrUndef())
1785  return val;
1786 
1787  // Lazy bindings are usually handled through getExistingLazyBinding().
1788  // We should unify these two code paths at some point.
1789  if (val.getAs<nonloc::LazyCompoundVal>() ||
1790  val.getAs<nonloc::CompoundVal>())
1791  return val;
1792 
1793  llvm_unreachable("Unknown default value");
1794  }
1795 
1796  return None;
1797 }
1798 
1799 SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion,
1800  RegionBindingsRef LazyBinding) {
1801  SVal Result;
1802  if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion))
1803  Result = getBindingForElement(LazyBinding, ER);
1804  else
1805  Result = getBindingForField(LazyBinding,
1806  cast<FieldRegion>(LazyBindingRegion));
1807 
1808  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1809  // default value for /part/ of an aggregate from a default value for the
1810  // /entire/ aggregate. The most common case of this is when struct Outer
1811  // has as its first member a struct Inner, which is copied in from a stack
1812  // variable. In this case, even if the Outer's default value is symbolic, 0,
1813  // or unknown, it gets overridden by the Inner's default value of undefined.
1814  //
1815  // This is a general problem -- if the Inner is zero-initialized, the Outer
1816  // will now look zero-initialized. The proper way to solve this is with a
1817  // new version of RegionStore that tracks the extent of a binding as well
1818  // as the offset.
1819  //
1820  // This hack only takes care of the undefined case because that can very
1821  // quickly result in a warning.
1822  if (Result.isUndef())
1823  Result = UnknownVal();
1824 
1825  return Result;
1826 }
1827 
1828 SVal
1829 RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
1830  const TypedValueRegion *R,
1831  QualType Ty) {
1832 
1833  // At this point we have already checked in either getBindingForElement or
1834  // getBindingForField if 'R' has a direct binding.
1835 
1836  // Lazy binding?
1837  Store lazyBindingStore = nullptr;
1838  const SubRegion *lazyBindingRegion = nullptr;
1839  std::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R);
1840  if (lazyBindingRegion)
1841  return getLazyBinding(lazyBindingRegion,
1842  getRegionBindings(lazyBindingStore));
1843 
1844  // Record whether or not we see a symbolic index. That can completely
1845  // be out of scope of our lookup.
1846  bool hasSymbolicIndex = false;
1847 
1848  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1849  // default value for /part/ of an aggregate from a default value for the
1850  // /entire/ aggregate. The most common case of this is when struct Outer
1851  // has as its first member a struct Inner, which is copied in from a stack
1852  // variable. In this case, even if the Outer's default value is symbolic, 0,
1853  // or unknown, it gets overridden by the Inner's default value of undefined.
1854  //
1855  // This is a general problem -- if the Inner is zero-initialized, the Outer
1856  // will now look zero-initialized. The proper way to solve this is with a
1857  // new version of RegionStore that tracks the extent of a binding as well
1858  // as the offset.
1859  //
1860  // This hack only takes care of the undefined case because that can very
1861  // quickly result in a warning.
1862  bool hasPartialLazyBinding = false;
1863 
1864  const SubRegion *SR = R;
1865  while (SR) {
1866  const MemRegion *Base = SR->getSuperRegion();
1867  if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) {
1868  if (D->getAs<nonloc::LazyCompoundVal>()) {
1869  hasPartialLazyBinding = true;
1870  break;
1871  }
1872 
1873  return *D;
1874  }
1875 
1876  if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) {
1877  NonLoc index = ER->getIndex();
1878  if (!index.isConstant())
1879  hasSymbolicIndex = true;
1880  }
1881 
1882  // If our super region is a field or element itself, walk up the region
1883  // hierarchy to see if there is a default value installed in an ancestor.
1884  SR = dyn_cast<SubRegion>(Base);
1885  }
1886 
1887  if (R->hasStackNonParametersStorage()) {
1888  if (isa<ElementRegion>(R)) {
1889  // Currently we don't reason specially about Clang-style vectors. Check
1890  // if superR is a vector and if so return Unknown.
1891  if (const TypedValueRegion *typedSuperR =
1892  dyn_cast<TypedValueRegion>(R->getSuperRegion())) {
1893  if (typedSuperR->getValueType()->isVectorType())
1894  return UnknownVal();
1895  }
1896  }
1897 
1898  // FIXME: We also need to take ElementRegions with symbolic indexes into
1899  // account. This case handles both directly accessing an ElementRegion
1900  // with a symbolic offset, but also fields within an element with
1901  // a symbolic offset.
1902  if (hasSymbolicIndex)
1903  return UnknownVal();
1904 
1905  if (!hasPartialLazyBinding)
1906  return UndefinedVal();
1907  }
1908 
1909  // All other values are symbolic.
1910  return svalBuilder.getRegionValueSymbolVal(R);
1911 }
1912 
1913 SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B,
1914  const ObjCIvarRegion* R) {
1915  // Check if the region has a binding.
1916  if (const Optional<SVal> &V = B.getDirectBinding(R))
1917  return *V;
1918 
1919  const MemRegion *superR = R->getSuperRegion();
1920 
1921  // Check if the super region has a default binding.
1922  if (const Optional<SVal> &V = B.getDefaultBinding(superR)) {
1923  if (SymbolRef parentSym = V->getAsSymbol())
1924  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1925 
1926  // Other cases: give up.
1927  return UnknownVal();
1928  }
1929 
1930  return getBindingForLazySymbol(R);
1931 }
1932 
1933 SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B,
1934  const VarRegion *R) {
1935 
1936  // Check if the region has a binding.
1937  if (const Optional<SVal> &V = B.getDirectBinding(R))
1938  return *V;
1939 
1940  // Lazily derive a value for the VarRegion.
1941  const VarDecl *VD = R->getDecl();
1942  const MemSpaceRegion *MS = R->getMemorySpace();
1943 
1944  // Arguments are always symbolic.
1945  if (isa<StackArgumentsSpaceRegion>(MS))
1946  return svalBuilder.getRegionValueSymbolVal(R);
1947 
1948  // Is 'VD' declared constant? If so, retrieve the constant value.
1949  if (VD->getType().isConstQualified()) {
1950  if (const Expr *Init = VD->getInit()) {
1951  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1952  return *V;
1953 
1954  // If the variable is const qualified and has an initializer but
1955  // we couldn't evaluate initializer to a value, treat the value as
1956  // unknown.
1957  return UnknownVal();
1958  }
1959  }
1960 
1961  // This must come after the check for constants because closure-captured
1962  // constant variables may appear in UnknownSpaceRegion.
1963  if (isa<UnknownSpaceRegion>(MS))
1964  return svalBuilder.getRegionValueSymbolVal(R);
1965 
1966  if (isa<GlobalsSpaceRegion>(MS)) {
1967  QualType T = VD->getType();
1968 
1969  // Function-scoped static variables are default-initialized to 0; if they
1970  // have an initializer, it would have been processed by now.
1971  // FIXME: This is only true when we're starting analysis from main().
1972  // We're losing a lot of coverage here.
1973  if (isa<StaticGlobalSpaceRegion>(MS))
1974  return svalBuilder.makeZeroVal(T);
1975 
1976  if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) {
1977  assert(!V->getAs<nonloc::LazyCompoundVal>());
1978  return V.getValue();
1979  }
1980 
1981  return svalBuilder.getRegionValueSymbolVal(R);
1982  }
1983 
1984  return UndefinedVal();
1985 }
1986 
1987 SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
1988  // All other values are symbolic.
1989  return svalBuilder.getRegionValueSymbolVal(R);
1990 }
1991 
1992 const RegionStoreManager::SValListTy &
1993 RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) {
1994  // First, check the cache.
1995  LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData());
1996  if (I != LazyBindingsMap.end())
1997  return I->second;
1998 
1999  // If we don't have a list of values cached, start constructing it.
2000  SValListTy List;
2001 
2002  const SubRegion *LazyR = LCV.getRegion();
2003  RegionBindingsRef B = getRegionBindings(LCV.getStore());
2004 
2005  // If this region had /no/ bindings at the time, there are no interesting
2006  // values to return.
2007  const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion());
2008  if (!Cluster)
2009  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2010 
2012  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR,
2013  /*IncludeAllDefaultBindings=*/true);
2014  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
2015  E = Bindings.end();
2016  I != E; ++I) {
2017  SVal V = I->second;
2018  if (V.isUnknownOrUndef() || V.isConstant())
2019  continue;
2020 
2021  if (Optional<nonloc::LazyCompoundVal> InnerLCV =
2022  V.getAs<nonloc::LazyCompoundVal>()) {
2023  const SValListTy &InnerList = getInterestingValues(*InnerLCV);
2024  List.insert(List.end(), InnerList.begin(), InnerList.end());
2025  continue;
2026  }
2027 
2028  List.push_back(V);
2029  }
2030 
2031  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2032 }
2033 
2034 NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B,
2035  const TypedValueRegion *R) {
2037  getExistingLazyBinding(svalBuilder, B, R, false))
2038  return *V;
2039 
2040  return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R);
2041 }
2042 
2043 static bool isRecordEmpty(const RecordDecl *RD) {
2044  if (!RD->field_empty())
2045  return false;
2046  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD))
2047  return CRD->getNumBases() == 0;
2048  return true;
2049 }
2050 
2051 SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B,
2052  const TypedValueRegion *R) {
2053  const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl();
2054  if (!RD->getDefinition() || isRecordEmpty(RD))
2055  return UnknownVal();
2056 
2057  return createLazyBinding(B, R);
2058 }
2059 
2060 SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B,
2061  const TypedValueRegion *R) {
2062  assert(Ctx.getAsConstantArrayType(R->getValueType()) &&
2063  "Only constant array types can have compound bindings.");
2064 
2065  return createLazyBinding(B, R);
2066 }
2067 
2068 bool RegionStoreManager::includedInBindings(Store store,
2069  const MemRegion *region) const {
2070  RegionBindingsRef B = getRegionBindings(store);
2071  region = region->getBaseRegion();
2072 
2073  // Quick path: if the base is the head of a cluster, the region is live.
2074  if (B.lookup(region))
2075  return true;
2076 
2077  // Slow path: if the region is the VALUE of any binding, it is live.
2078  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) {
2079  const ClusterBindings &Cluster = RI.getData();
2080  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2081  CI != CE; ++CI) {
2082  const SVal &D = CI.getData();
2083  if (const MemRegion *R = D.getAsRegion())
2084  if (R->getBaseRegion() == region)
2085  return true;
2086  }
2087  }
2088 
2089  return false;
2090 }
2091 
2092 //===----------------------------------------------------------------------===//
2093 // Binding values to regions.
2094 //===----------------------------------------------------------------------===//
2095 
2096 StoreRef RegionStoreManager::killBinding(Store ST, Loc L) {
2097  if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>())
2098  if (const MemRegion* R = LV->getRegion())
2099  return StoreRef(getRegionBindings(ST).removeBinding(R)
2100  .asImmutableMap()
2101  .getRootWithoutRetain(),
2102  *this);
2103 
2104  return StoreRef(ST, *this);
2105 }
2106 
2107 RegionBindingsRef
2108 RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) {
2109  if (L.getAs<loc::ConcreteInt>())
2110  return B;
2111 
2112  // If we get here, the location should be a region.
2113  const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion();
2114 
2115  // Check if the region is a struct region.
2116  if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) {
2117  QualType Ty = TR->getValueType();
2118  if (Ty->isArrayType())
2119  return bindArray(B, TR, V);
2120  if (Ty->isStructureOrClassType())
2121  return bindStruct(B, TR, V);
2122  if (Ty->isVectorType())
2123  return bindVector(B, TR, V);
2124  if (Ty->isUnionType())
2125  return bindAggregate(B, TR, V);
2126  }
2127 
2128  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
2129  // Binding directly to a symbolic region should be treated as binding
2130  // to element 0.
2131  QualType T = SR->getSymbol()->getType();
2132  if (T->isAnyPointerType() || T->isReferenceType())
2133  T = T->getPointeeType();
2134 
2135  R = GetElementZeroRegion(SR, T);
2136  }
2137 
2138  assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) &&
2139  "'this' pointer is not an l-value and is not assignable");
2140 
2141  // Clear out bindings that may overlap with this binding.
2142  RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R));
2143  return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V);
2144 }
2145 
2146 RegionBindingsRef
2147 RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B,
2148  const MemRegion *R,
2149  QualType T) {
2150  SVal V;
2151 
2152  if (Loc::isLocType(T))
2153  V = svalBuilder.makeNull();
2154  else if (T->isIntegralOrEnumerationType())
2155  V = svalBuilder.makeZeroVal(T);
2156  else if (T->isStructureOrClassType() || T->isArrayType()) {
2157  // Set the default value to a zero constant when it is a structure
2158  // or array. The type doesn't really matter.
2159  V = svalBuilder.makeZeroVal(Ctx.IntTy);
2160  }
2161  else {
2162  // We can't represent values of this type, but we still need to set a value
2163  // to record that the region has been initialized.
2164  // If this assertion ever fires, a new case should be added above -- we
2165  // should know how to default-initialize any value we can symbolicate.
2166  assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
2167  V = UnknownVal();
2168  }
2169 
2170  return B.addBinding(R, BindingKey::Default, V);
2171 }
2172 
2173 RegionBindingsRef
2174 RegionStoreManager::bindArray(RegionBindingsConstRef B,
2175  const TypedValueRegion* R,
2176  SVal Init) {
2177 
2178  const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType()));
2179  QualType ElementTy = AT->getElementType();
2180  Optional<uint64_t> Size;
2181 
2182  if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT))
2183  Size = CAT->getSize().getZExtValue();
2184 
2185  // Check if the init expr is a literal. If so, bind the rvalue instead.
2186  // FIXME: It's not responsibility of the Store to transform this lvalue
2187  // to rvalue. ExprEngine or maybe even CFG should do this before binding.
2188  if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) {
2189  SVal V = getBinding(B.asStore(), *MRV, R->getValueType());
2190  return bindAggregate(B, R, V);
2191  }
2192 
2193  // Handle lazy compound values.
2194  if (Init.getAs<nonloc::LazyCompoundVal>())
2195  return bindAggregate(B, R, Init);
2196 
2197  if (Init.isUnknown())
2198  return bindAggregate(B, R, UnknownVal());
2199 
2200  // Remaining case: explicit compound values.
2201  const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>();
2202  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2203  uint64_t i = 0;
2204 
2205  RegionBindingsRef NewB(B);
2206 
2207  for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) {
2208  // The init list might be shorter than the array length.
2209  if (VI == VE)
2210  break;
2211 
2212  const NonLoc &Idx = svalBuilder.makeArrayIndex(i);
2213  const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx);
2214 
2215  if (ElementTy->isStructureOrClassType())
2216  NewB = bindStruct(NewB, ER, *VI);
2217  else if (ElementTy->isArrayType())
2218  NewB = bindArray(NewB, ER, *VI);
2219  else
2220  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2221  }
2222 
2223  // If the init list is shorter than the array length (or the array has
2224  // variable length), set the array default value. Values that are already set
2225  // are not overwritten.
2226  if (!Size.hasValue() || i < Size.getValue())
2227  NewB = setImplicitDefaultValue(NewB, R, ElementTy);
2228 
2229  return NewB;
2230 }
2231 
2232 RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B,
2233  const TypedValueRegion* R,
2234  SVal V) {
2235  QualType T = R->getValueType();
2236  assert(T->isVectorType());
2237  const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs.
2238 
2239  // Handle lazy compound values and symbolic values.
2240  if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>())
2241  return bindAggregate(B, R, V);
2242 
2243  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2244  // that we are binding symbolic struct value. Kill the field values, and if
2245  // the value is symbolic go and bind it as a "default" binding.
2246  if (!V.getAs<nonloc::CompoundVal>()) {
2247  return bindAggregate(B, R, UnknownVal());
2248  }
2249 
2250  QualType ElemType = VT->getElementType();
2251  nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>();
2252  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2253  unsigned index = 0, numElements = VT->getNumElements();
2254  RegionBindingsRef NewB(B);
2255 
2256  for ( ; index != numElements ; ++index) {
2257  if (VI == VE)
2258  break;
2259 
2260  NonLoc Idx = svalBuilder.makeArrayIndex(index);
2261  const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx);
2262 
2263  if (ElemType->isArrayType())
2264  NewB = bindArray(NewB, ER, *VI);
2265  else if (ElemType->isStructureOrClassType())
2266  NewB = bindStruct(NewB, ER, *VI);
2267  else
2268  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2269  }
2270  return NewB;
2271 }
2272 
2274 RegionStoreManager::tryBindSmallStruct(RegionBindingsConstRef B,
2275  const TypedValueRegion *R,
2276  const RecordDecl *RD,
2277  nonloc::LazyCompoundVal LCV) {
2278  FieldVector Fields;
2279 
2280  if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(RD))
2281  if (Class->getNumBases() != 0 || Class->getNumVBases() != 0)
2282  return None;
2283 
2284  for (const auto *FD : RD->fields()) {
2285  if (FD->isUnnamedBitfield())
2286  continue;
2287 
2288  // If there are too many fields, or if any of the fields are aggregates,
2289  // just use the LCV as a default binding.
2290  if (Fields.size() == SmallStructLimit)
2291  return None;
2292 
2293  QualType Ty = FD->getType();
2294  if (!(Ty->isScalarType() || Ty->isReferenceType()))
2295  return None;
2296 
2297  Fields.push_back(FD);
2298  }
2299 
2300  RegionBindingsRef NewB = B;
2301 
2302  for (FieldVector::iterator I = Fields.begin(), E = Fields.end(); I != E; ++I){
2303  const FieldRegion *SourceFR = MRMgr.getFieldRegion(*I, LCV.getRegion());
2304  SVal V = getBindingForField(getRegionBindings(LCV.getStore()), SourceFR);
2305 
2306  const FieldRegion *DestFR = MRMgr.getFieldRegion(*I, R);
2307  NewB = bind(NewB, loc::MemRegionVal(DestFR), V);
2308  }
2309 
2310  return NewB;
2311 }
2312 
2313 RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B,
2314  const TypedValueRegion* R,
2315  SVal V) {
2316  if (!Features.supportsFields())
2317  return B;
2318 
2319  QualType T = R->getValueType();
2320  assert(T->isStructureOrClassType());
2321 
2322  const RecordType* RT = T->getAs<RecordType>();
2323  const RecordDecl *RD = RT->getDecl();
2324 
2325  if (!RD->isCompleteDefinition())
2326  return B;
2327 
2328  // Handle lazy compound values and symbolic values.
2330  V.getAs<nonloc::LazyCompoundVal>()) {
2331  if (Optional<RegionBindingsRef> NewB = tryBindSmallStruct(B, R, RD, *LCV))
2332  return *NewB;
2333  return bindAggregate(B, R, V);
2334  }
2335  if (V.getAs<nonloc::SymbolVal>())
2336  return bindAggregate(B, R, V);
2337 
2338  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2339  // that we are binding symbolic struct value. Kill the field values, and if
2340  // the value is symbolic go and bind it as a "default" binding.
2341  if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>())
2342  return bindAggregate(B, R, UnknownVal());
2343 
2344  const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>();
2345  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2346 
2348  RegionBindingsRef NewB(B);
2349 
2350  for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
2351 
2352  if (VI == VE)
2353  break;
2354 
2355  // Skip any unnamed bitfields to stay in sync with the initializers.
2356  if (FI->isUnnamedBitfield())
2357  continue;
2358 
2359  QualType FTy = FI->getType();
2360  const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R);
2361 
2362  if (FTy->isArrayType())
2363  NewB = bindArray(NewB, FR, *VI);
2364  else if (FTy->isStructureOrClassType())
2365  NewB = bindStruct(NewB, FR, *VI);
2366  else
2367  NewB = bind(NewB, loc::MemRegionVal(FR), *VI);
2368  ++VI;
2369  }
2370 
2371  // There may be fewer values in the initialize list than the fields of struct.
2372  if (FI != FE) {
2373  NewB = NewB.addBinding(R, BindingKey::Default,
2374  svalBuilder.makeIntVal(0, false));
2375  }
2376 
2377  return NewB;
2378 }
2379 
2380 RegionBindingsRef
2381 RegionStoreManager::bindAggregate(RegionBindingsConstRef B,
2382  const TypedRegion *R,
2383  SVal Val) {
2384  // Remove the old bindings, using 'R' as the root of all regions
2385  // we will invalidate. Then add the new binding.
2386  return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val);
2387 }
2388 
2389 //===----------------------------------------------------------------------===//
2390 // State pruning.
2391 //===----------------------------------------------------------------------===//
2392 
2393 namespace {
2394 class RemoveDeadBindingsWorker
2395  : public ClusterAnalysis<RemoveDeadBindingsWorker> {
2396  using ChildrenListTy = SmallVector<const SymbolDerived *, 4>;
2397  using MapParentsToDerivedTy = llvm::DenseMap<SymbolRef, ChildrenListTy>;
2398 
2399  MapParentsToDerivedTy ParentsToDerived;
2400  SymbolReaper &SymReaper;
2401  const StackFrameContext *CurrentLCtx;
2402 
2403 public:
2404  RemoveDeadBindingsWorker(RegionStoreManager &rm,
2405  ProgramStateManager &stateMgr,
2406  RegionBindingsRef b, SymbolReaper &symReaper,
2407  const StackFrameContext *LCtx)
2408  : ClusterAnalysis<RemoveDeadBindingsWorker>(rm, stateMgr, b),
2409  SymReaper(symReaper), CurrentLCtx(LCtx) {}
2410 
2411  // Called by ClusterAnalysis.
2412  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C);
2413  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
2414  using ClusterAnalysis<RemoveDeadBindingsWorker>::VisitCluster;
2415 
2416  using ClusterAnalysis::AddToWorkList;
2417 
2418  bool AddToWorkList(const MemRegion *R);
2419 
2420  void VisitBinding(SVal V);
2421 
2422 private:
2423  void populateWorklistFromSymbol(SymbolRef s);
2424 };
2425 }
2426 
2427 bool RemoveDeadBindingsWorker::AddToWorkList(const MemRegion *R) {
2428  const MemRegion *BaseR = R->getBaseRegion();
2429  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
2430 }
2431 
2432 void RemoveDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
2433  const ClusterBindings &C) {
2434 
2435  if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) {
2436  if (SymReaper.isLive(VR))
2437  AddToWorkList(baseR, &C);
2438 
2439  return;
2440  }
2441 
2442  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) {
2443  if (SymReaper.isLive(SR->getSymbol())) {
2444  AddToWorkList(SR, &C);
2445  } else if (const auto *SD = dyn_cast<SymbolDerived>(SR->getSymbol())) {
2446  ParentsToDerived[SD->getParentSymbol()].push_back(SD);
2447  }
2448 
2449  return;
2450  }
2451 
2452  if (isa<NonStaticGlobalSpaceRegion>(baseR)) {
2453  AddToWorkList(baseR, &C);
2454  return;
2455  }
2456 
2457  // CXXThisRegion in the current or parent location context is live.
2458  if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) {
2459  const auto *StackReg =
2460  cast<StackArgumentsSpaceRegion>(TR->getSuperRegion());
2461  const StackFrameContext *RegCtx = StackReg->getStackFrame();
2462  if (CurrentLCtx &&
2463  (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx)))
2464  AddToWorkList(TR, &C);
2465  }
2466 }
2467 
2468 void RemoveDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
2469  const ClusterBindings *C) {
2470  if (!C)
2471  return;
2472 
2473  // Mark the symbol for any SymbolicRegion with live bindings as live itself.
2474  // This means we should continue to track that symbol.
2475  if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR))
2476  SymReaper.markLive(SymR->getSymbol());
2477 
2478  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) {
2479  // Element index of a binding key is live.
2480  SymReaper.markElementIndicesLive(I.getKey().getRegion());
2481 
2482  VisitBinding(I.getData());
2483  }
2484 }
2485 
2486 void RemoveDeadBindingsWorker::VisitBinding(SVal V) {
2487  // Is it a LazyCompoundVal? All referenced regions are live as well.
2489  V.getAs<nonloc::LazyCompoundVal>()) {
2490 
2491  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
2492 
2493  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
2494  E = Vals.end();
2495  I != E; ++I)
2496  VisitBinding(*I);
2497 
2498  return;
2499  }
2500 
2501  // If V is a region, then add it to the worklist.
2502  if (const MemRegion *R = V.getAsRegion()) {
2503  AddToWorkList(R);
2504 
2505  if (const auto *TVR = dyn_cast<TypedValueRegion>(R)) {
2506  DefinedOrUnknownSVal RVS =
2507  RM.getSValBuilder().getRegionValueSymbolVal(TVR);
2508  if (const MemRegion *SR = RVS.getAsRegion()) {
2509  AddToWorkList(SR);
2510  }
2511  }
2512 
2513  SymReaper.markLive(R);
2514 
2515  // All regions captured by a block are also live.
2516  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) {
2517  BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(),
2518  E = BR->referenced_vars_end();
2519  for ( ; I != E; ++I)
2520  AddToWorkList(I.getCapturedRegion());
2521  }
2522  }
2523 
2524 
2525  // Update the set of live symbols.
2526  for (auto SI = V.symbol_begin(), SE = V.symbol_end(); SI != SE; ++SI) {
2527  populateWorklistFromSymbol(*SI);
2528 
2529  for (const auto *SD : ParentsToDerived[*SI])
2530  populateWorklistFromSymbol(SD);
2531 
2532  SymReaper.markLive(*SI);
2533  }
2534 }
2535 
2536 void RemoveDeadBindingsWorker::populateWorklistFromSymbol(SymbolRef S) {
2537  if (const auto *SD = dyn_cast<SymbolData>(S)) {
2538  if (Loc::isLocType(SD->getType()) && !SymReaper.isLive(SD)) {
2539  const SymbolicRegion *SR = RM.getRegionManager().getSymbolicRegion(SD);
2540 
2541  if (B.contains(SR))
2542  AddToWorkList(SR);
2543 
2544  const SymbolicRegion *SHR =
2545  RM.getRegionManager().getSymbolicHeapRegion(SD);
2546  if (B.contains(SHR))
2547  AddToWorkList(SHR);
2548  }
2549  }
2550 }
2551 
2552 StoreRef RegionStoreManager::removeDeadBindings(Store store,
2553  const StackFrameContext *LCtx,
2554  SymbolReaper& SymReaper) {
2555  RegionBindingsRef B = getRegionBindings(store);
2556  RemoveDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
2557  W.GenerateClusters();
2558 
2559  // Enqueue the region roots onto the worklist.
2560  for (SymbolReaper::region_iterator I = SymReaper.region_begin(),
2561  E = SymReaper.region_end(); I != E; ++I) {
2562  W.AddToWorkList(*I);
2563  }
2564 
2565  W.RunWorkList();
2566 
2567  // We have now scanned the store, marking reachable regions and symbols
2568  // as live. We now remove all the regions that are dead from the store
2569  // as well as update DSymbols with the set symbols that are now dead.
2570  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
2571  const MemRegion *Base = I.getKey();
2572 
2573  // If the cluster has been visited, we know the region has been marked.
2574  if (W.isVisited(Base))
2575  continue;
2576 
2577  // Remove the dead entry.
2578  B = B.remove(Base);
2579 
2580  if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base))
2581  SymReaper.maybeDead(SymR->getSymbol());
2582 
2583  // Mark all non-live symbols that this binding references as dead.
2584  const ClusterBindings &Cluster = I.getData();
2585  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2586  CI != CE; ++CI) {
2587  SVal X = CI.getData();
2588  SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end();
2589  for (; SI != SE; ++SI)
2590  SymReaper.maybeDead(*SI);
2591  }
2592  }
2593 
2594  return StoreRef(B.asStore(), *this);
2595 }
2596 
2597 //===----------------------------------------------------------------------===//
2598 // Utility methods.
2599 //===----------------------------------------------------------------------===//
2600 
2601 void RegionStoreManager::print(Store store, raw_ostream &OS,
2602  const char* nl) {
2603  RegionBindingsRef B = getRegionBindings(store);
2604  OS << "Store (direct and default bindings), "
2605  << B.asStore()
2606  << " :" << nl;
2607  B.dump(OS, nl);
2608 }
A (possibly-)qualified type.
Definition: Type.h:642
bool isArrayType() const
Definition: Type.h:6319
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:3793
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:2808
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:2843
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6683
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:3784
const internal::VariadicDynCastAllOfMatcher< Decl, VarDecl > varDecl
Matches variable declarations.
std::unique_ptr< StoreManager > CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr)
Represents a struct/union/class.
Definition: Decl.h:3585
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:3766
field_range fields() const
Definition: Decl.h:3776
Represents a member of a struct/union/class.
Definition: Decl.h:2571
static bool canSymbolicate(QualType T)
bool isReferenceType() const
Definition: Type.h:6282
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:6597
static bool isLocType(QualType T)
Definition: SVals.h:327
unsigned getLength() const
Definition: Expr.h:1654
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:6582
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:1035
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6746
uint32_t getCodeUnit(size_t i) const
Definition: Expr.h:1643
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:3164
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:6105
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:2713
bool isAnyPointerType() const
Definition: Type.h:6274
bool operator<(DeclarationName LHS, DeclarationName RHS)
Ordering on two declaration names.
bool isVectorType() const
Definition: Type.h:6355
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:36
const Expr * getInit() const
Definition: Decl.h:1219
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:2016
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:4346
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:13803
static bool isUnionField(const FieldRegion *FR)
Represents a C++ struct/union/class.
Definition: DeclCXX.h:300
bool isVoidType() const
Definition: Type.h:6497
StringLiteral - This represents a string literal expression, e.g.
Definition: Expr.h:1573
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:2868