clang  10.0.0svn
RegionStore.cpp
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1 //== RegionStore.cpp - Field-sensitive store model --------------*- C++ -*--==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines a basic region store model. In this model, we do have field
10 // sensitivity. But we assume nothing about the heap shape. So recursive data
11 // structures are largely ignored. Basically we do 1-limiting analysis.
12 // Parameter pointers are assumed with no aliasing. Pointee objects of
13 // parameters are created lazily.
14 //
15 //===----------------------------------------------------------------------===//
16 
17 #include "clang/AST/Attr.h"
18 #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  LLVM_DUMP_METHOD 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 raw_ostream &operator<<(raw_ostream &Out, BindingKey K) {
125  Out << "\"kind\": \"" << (K.isDirect() ? "Direct" : "Default")
126  << "\", \"offset\": ";
127 
128  if (!K.hasSymbolicOffset())
129  Out << K.getOffset();
130  else
131  Out << "null";
132 
133  return Out;
134 }
135 
136 } // namespace llvm
137 
138 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
139 void BindingKey::dump() const { llvm::errs() << *this; }
140 #endif
141 
142 //===----------------------------------------------------------------------===//
143 // Actual Store type.
144 //===----------------------------------------------------------------------===//
145 
146 typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings;
147 typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef;
148 typedef std::pair<BindingKey, SVal> BindingPair;
149 
150 typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings>
152 
153 namespace {
154 class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *,
155  ClusterBindings> {
156  ClusterBindings::Factory *CBFactory;
157 
158  // This flag indicates whether the current bindings are within the analysis
159  // that has started from main(). It affects how we perform loads from
160  // global variables that have initializers: if we have observed the
161  // program execution from the start and we know that these variables
162  // have not been overwritten yet, we can be sure that their initializers
163  // are still relevant. This flag never gets changed when the bindings are
164  // updated, so it could potentially be moved into RegionStoreManager
165  // (as if it's the same bindings but a different loading procedure)
166  // however that would have made the manager needlessly stateful.
167  bool IsMainAnalysis;
168 
169 public:
170  typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>
171  ParentTy;
172 
173  RegionBindingsRef(ClusterBindings::Factory &CBFactory,
174  const RegionBindings::TreeTy *T,
175  RegionBindings::TreeTy::Factory *F,
176  bool IsMainAnalysis)
177  : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F),
178  CBFactory(&CBFactory), IsMainAnalysis(IsMainAnalysis) {}
179 
180  RegionBindingsRef(const ParentTy &P,
181  ClusterBindings::Factory &CBFactory,
182  bool IsMainAnalysis)
183  : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P),
184  CBFactory(&CBFactory), IsMainAnalysis(IsMainAnalysis) {}
185 
186  RegionBindingsRef add(key_type_ref K, data_type_ref D) const {
187  return RegionBindingsRef(static_cast<const ParentTy *>(this)->add(K, D),
188  *CBFactory, IsMainAnalysis);
189  }
190 
191  RegionBindingsRef remove(key_type_ref K) const {
192  return RegionBindingsRef(static_cast<const ParentTy *>(this)->remove(K),
193  *CBFactory, IsMainAnalysis);
194  }
195 
196  RegionBindingsRef addBinding(BindingKey K, SVal V) const;
197 
198  RegionBindingsRef addBinding(const MemRegion *R,
199  BindingKey::Kind k, SVal V) const;
200 
201  const SVal *lookup(BindingKey K) const;
202  const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const;
203  using llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>::lookup;
204 
205  RegionBindingsRef removeBinding(BindingKey K);
206 
207  RegionBindingsRef removeBinding(const MemRegion *R,
208  BindingKey::Kind k);
209 
210  RegionBindingsRef removeBinding(const MemRegion *R) {
211  return removeBinding(R, BindingKey::Direct).
212  removeBinding(R, BindingKey::Default);
213  }
214 
215  Optional<SVal> getDirectBinding(const MemRegion *R) const;
216 
217  /// getDefaultBinding - Returns an SVal* representing an optional default
218  /// binding associated with a region and its subregions.
219  Optional<SVal> getDefaultBinding(const MemRegion *R) const;
220 
221  /// Return the internal tree as a Store.
222  Store asStore() const {
223  llvm::PointerIntPair<Store, 1, bool> Ptr = {
224  asImmutableMap().getRootWithoutRetain(), IsMainAnalysis};
225  return reinterpret_cast<Store>(Ptr.getOpaqueValue());
226  }
227 
228  bool isMainAnalysis() const {
229  return IsMainAnalysis;
230  }
231 
232  void printJson(raw_ostream &Out, const char *NL = "\n",
233  unsigned int Space = 0, bool IsDot = false) const {
234  for (iterator I = begin(); I != end(); ++I) {
235  // TODO: We might need a .printJson for I.getKey() as well.
236  Indent(Out, Space, IsDot)
237  << "{ \"cluster\": \"" << I.getKey() << "\", \"pointer\": \""
238  << (const void *)I.getKey() << "\", \"items\": [" << NL;
239 
240  ++Space;
241  const ClusterBindings &CB = I.getData();
242  for (ClusterBindings::iterator CI = CB.begin(); CI != CB.end(); ++CI) {
243  Indent(Out, Space, IsDot) << "{ " << CI.getKey() << ", \"value\": ";
244  CI.getData().printJson(Out, /*AddQuotes=*/true);
245  Out << " }";
246  if (std::next(CI) != CB.end())
247  Out << ',';
248  Out << NL;
249  }
250 
251  --Space;
252  Indent(Out, Space, IsDot) << "]}";
253  if (std::next(I) != end())
254  Out << ',';
255  Out << NL;
256  }
257  }
258 
259  LLVM_DUMP_METHOD void dump() const { printJson(llvm::errs()); }
260 };
261 } // end anonymous namespace
262 
263 typedef const RegionBindingsRef& RegionBindingsConstRef;
264 
265 Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const {
266  return Optional<SVal>::create(lookup(R, BindingKey::Direct));
267 }
268 
269 Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const {
270  return Optional<SVal>::create(lookup(R, BindingKey::Default));
271 }
272 
273 RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const {
274  const MemRegion *Base = K.getBaseRegion();
275 
276  const ClusterBindings *ExistingCluster = lookup(Base);
277  ClusterBindings Cluster =
278  (ExistingCluster ? *ExistingCluster : CBFactory->getEmptyMap());
279 
280  ClusterBindings NewCluster = CBFactory->add(Cluster, K, V);
281  return add(Base, NewCluster);
282 }
283 
284 
285 RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R,
286  BindingKey::Kind k,
287  SVal V) const {
288  return addBinding(BindingKey::Make(R, k), V);
289 }
290 
291 const SVal *RegionBindingsRef::lookup(BindingKey K) const {
292  const ClusterBindings *Cluster = lookup(K.getBaseRegion());
293  if (!Cluster)
294  return nullptr;
295  return Cluster->lookup(K);
296 }
297 
298 const SVal *RegionBindingsRef::lookup(const MemRegion *R,
299  BindingKey::Kind k) const {
300  return lookup(BindingKey::Make(R, k));
301 }
302 
303 RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) {
304  const MemRegion *Base = K.getBaseRegion();
305  const ClusterBindings *Cluster = lookup(Base);
306  if (!Cluster)
307  return *this;
308 
309  ClusterBindings NewCluster = CBFactory->remove(*Cluster, K);
310  if (NewCluster.isEmpty())
311  return remove(Base);
312  return add(Base, NewCluster);
313 }
314 
315 RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R,
316  BindingKey::Kind k){
317  return removeBinding(BindingKey::Make(R, k));
318 }
319 
320 //===----------------------------------------------------------------------===//
321 // Fine-grained control of RegionStoreManager.
322 //===----------------------------------------------------------------------===//
323 
324 namespace {
325 struct minimal_features_tag {};
326 struct maximal_features_tag {};
327 
328 class RegionStoreFeatures {
329  bool SupportsFields;
330 public:
331  RegionStoreFeatures(minimal_features_tag) :
332  SupportsFields(false) {}
333 
334  RegionStoreFeatures(maximal_features_tag) :
335  SupportsFields(true) {}
336 
337  void enableFields(bool t) { SupportsFields = t; }
338 
339  bool supportsFields() const { return SupportsFields; }
340 };
341 }
342 
343 //===----------------------------------------------------------------------===//
344 // Main RegionStore logic.
345 //===----------------------------------------------------------------------===//
346 
347 namespace {
348 class InvalidateRegionsWorker;
349 
350 class RegionStoreManager : public StoreManager {
351 public:
352  const RegionStoreFeatures Features;
353 
354  RegionBindings::Factory RBFactory;
355  mutable ClusterBindings::Factory CBFactory;
356 
357  typedef std::vector<SVal> SValListTy;
358 private:
359  typedef llvm::DenseMap<const LazyCompoundValData *,
360  SValListTy> LazyBindingsMapTy;
361  LazyBindingsMapTy LazyBindingsMap;
362 
363  /// The largest number of fields a struct can have and still be
364  /// considered "small".
365  ///
366  /// This is currently used to decide whether or not it is worth "forcing" a
367  /// LazyCompoundVal on bind.
368  ///
369  /// This is controlled by 'region-store-small-struct-limit' option.
370  /// To disable all small-struct-dependent behavior, set the option to "0".
371  unsigned SmallStructLimit;
372 
373  /// A helper used to populate the work list with the given set of
374  /// regions.
375  void populateWorkList(InvalidateRegionsWorker &W,
376  ArrayRef<SVal> Values,
377  InvalidatedRegions *TopLevelRegions);
378 
379 public:
380  RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f)
381  : StoreManager(mgr), Features(f),
382  RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()),
383  SmallStructLimit(0) {
384  SubEngine &Eng = StateMgr.getOwningEngine();
385  AnalyzerOptions &Options = Eng.getAnalysisManager().options;
386  SmallStructLimit = Options.RegionStoreSmallStructLimit;
387  }
388 
389 
390  /// setImplicitDefaultValue - Set the default binding for the provided
391  /// MemRegion to the value implicitly defined for compound literals when
392  /// the value is not specified.
393  RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B,
394  const MemRegion *R, QualType T);
395 
396  /// ArrayToPointer - Emulates the "decay" of an array to a pointer
397  /// type. 'Array' represents the lvalue of the array being decayed
398  /// to a pointer, and the returned SVal represents the decayed
399  /// version of that lvalue (i.e., a pointer to the first element of
400  /// the array). This is called by ExprEngine when evaluating
401  /// casts from arrays to pointers.
402  SVal ArrayToPointer(Loc Array, QualType ElementTy) override;
403 
404  /// Creates the Store that correctly represents memory contents before
405  /// the beginning of the analysis of the given top-level stack frame.
406  StoreRef getInitialStore(const LocationContext *InitLoc) override {
407  bool IsMainAnalysis = false;
408  if (const auto *FD = dyn_cast<FunctionDecl>(InitLoc->getDecl()))
409  IsMainAnalysis = FD->isMain() && !Ctx.getLangOpts().CPlusPlus;
410  return StoreRef(RegionBindingsRef(
411  RegionBindingsRef::ParentTy(RBFactory.getEmptyMap(), RBFactory),
412  CBFactory, IsMainAnalysis).asStore(), *this);
413  }
414 
415  //===-------------------------------------------------------------------===//
416  // Binding values to regions.
417  //===-------------------------------------------------------------------===//
418  RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K,
419  const Expr *Ex,
420  unsigned Count,
421  const LocationContext *LCtx,
422  RegionBindingsRef B,
423  InvalidatedRegions *Invalidated);
424 
425  StoreRef invalidateRegions(Store store,
426  ArrayRef<SVal> Values,
427  const Expr *E, unsigned Count,
428  const LocationContext *LCtx,
429  const CallEvent *Call,
430  InvalidatedSymbols &IS,
431  RegionAndSymbolInvalidationTraits &ITraits,
432  InvalidatedRegions *Invalidated,
433  InvalidatedRegions *InvalidatedTopLevel) override;
434 
435  bool scanReachableSymbols(Store S, const MemRegion *R,
436  ScanReachableSymbols &Callbacks) override;
437 
438  RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B,
439  const SubRegion *R);
440 
441 public: // Part of public interface to class.
442 
443  StoreRef Bind(Store store, Loc LV, SVal V) override {
444  return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this);
445  }
446 
447  RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V);
448 
449  // BindDefaultInitial is only used to initialize a region with
450  // a default value.
451  StoreRef BindDefaultInitial(Store store, const MemRegion *R,
452  SVal V) override {
453  RegionBindingsRef B = getRegionBindings(store);
454  // Use other APIs when you have to wipe the region that was initialized
455  // earlier.
456  assert(!(B.getDefaultBinding(R) || B.getDirectBinding(R)) &&
457  "Double initialization!");
458  B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
459  return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
460  }
461 
462  // BindDefaultZero is used for zeroing constructors that may accidentally
463  // overwrite existing bindings.
464  StoreRef BindDefaultZero(Store store, const MemRegion *R) override {
465  // FIXME: The offsets of empty bases can be tricky because of
466  // of the so called "empty base class optimization".
467  // If a base class has been optimized out
468  // we should not try to create a binding, otherwise we should.
469  // Unfortunately, at the moment ASTRecordLayout doesn't expose
470  // the actual sizes of the empty bases
471  // and trying to infer them from offsets/alignments
472  // seems to be error-prone and non-trivial because of the trailing padding.
473  // As a temporary mitigation we don't create bindings for empty bases.
474  if (const auto *BR = dyn_cast<CXXBaseObjectRegion>(R))
475  if (BR->getDecl()->isEmpty())
476  return StoreRef(store, *this);
477 
478  RegionBindingsRef B = getRegionBindings(store);
479  SVal V = svalBuilder.makeZeroVal(Ctx.CharTy);
480  B = removeSubRegionBindings(B, cast<SubRegion>(R));
481  B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
482  return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
483  }
484 
485  /// Attempt to extract the fields of \p LCV and bind them to the struct region
486  /// \p R.
487  ///
488  /// This path is used when it seems advantageous to "force" loading the values
489  /// within a LazyCompoundVal to bind memberwise to the struct region, rather
490  /// than using a Default binding at the base of the entire region. This is a
491  /// heuristic attempting to avoid building long chains of LazyCompoundVals.
492  ///
493  /// \returns The updated store bindings, or \c None if binding non-lazily
494  /// would be too expensive.
495  Optional<RegionBindingsRef> tryBindSmallStruct(RegionBindingsConstRef B,
496  const TypedValueRegion *R,
497  const RecordDecl *RD,
498  nonloc::LazyCompoundVal LCV);
499 
500  /// BindStruct - Bind a compound value to a structure.
501  RegionBindingsRef bindStruct(RegionBindingsConstRef B,
502  const TypedValueRegion* R, SVal V);
503 
504  /// BindVector - Bind a compound value to a vector.
505  RegionBindingsRef bindVector(RegionBindingsConstRef B,
506  const TypedValueRegion* R, SVal V);
507 
508  RegionBindingsRef bindArray(RegionBindingsConstRef B,
509  const TypedValueRegion* R,
510  SVal V);
511 
512  /// Clears out all bindings in the given region and assigns a new value
513  /// as a Default binding.
514  RegionBindingsRef bindAggregate(RegionBindingsConstRef B,
515  const TypedRegion *R,
516  SVal DefaultVal);
517 
518  /// Create a new store with the specified binding removed.
519  /// \param ST the original store, that is the basis for the new store.
520  /// \param L the location whose binding should be removed.
521  StoreRef killBinding(Store ST, Loc L) override;
522 
523  void incrementReferenceCount(Store store) override {
524  getRegionBindings(store).manualRetain();
525  }
526 
527  /// If the StoreManager supports it, decrement the reference count of
528  /// the specified Store object. If the reference count hits 0, the memory
529  /// associated with the object is recycled.
530  void decrementReferenceCount(Store store) override {
531  getRegionBindings(store).manualRelease();
532  }
533 
534  bool includedInBindings(Store store, const MemRegion *region) const override;
535 
536  /// Return the value bound to specified location in a given state.
537  ///
538  /// The high level logic for this method is this:
539  /// getBinding (L)
540  /// if L has binding
541  /// return L's binding
542  /// else if L is in killset
543  /// return unknown
544  /// else
545  /// if L is on stack or heap
546  /// return undefined
547  /// else
548  /// return symbolic
549  SVal getBinding(Store S, Loc L, QualType T) override {
550  return getBinding(getRegionBindings(S), L, T);
551  }
552 
553  Optional<SVal> getDefaultBinding(Store S, const MemRegion *R) override {
554  RegionBindingsRef B = getRegionBindings(S);
555  // Default bindings are always applied over a base region so look up the
556  // base region's default binding, otherwise the lookup will fail when R
557  // is at an offset from R->getBaseRegion().
558  return B.getDefaultBinding(R->getBaseRegion());
559  }
560 
561  SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType());
562 
563  SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R);
564 
565  SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R);
566 
567  SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R);
568 
569  SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R);
570 
571  SVal getBindingForLazySymbol(const TypedValueRegion *R);
572 
573  SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
574  const TypedValueRegion *R,
575  QualType Ty);
576 
577  SVal getLazyBinding(const SubRegion *LazyBindingRegion,
578  RegionBindingsRef LazyBinding);
579 
580  /// Get bindings for the values in a struct and return a CompoundVal, used
581  /// when doing struct copy:
582  /// struct s x, y;
583  /// x = y;
584  /// y's value is retrieved by this method.
585  SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R);
586  SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R);
587  NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R);
588 
589  /// Used to lazily generate derived symbols for bindings that are defined
590  /// implicitly by default bindings in a super region.
591  ///
592  /// Note that callers may need to specially handle LazyCompoundVals, which
593  /// are returned as is in case the caller needs to treat them differently.
594  Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
595  const MemRegion *superR,
596  const TypedValueRegion *R,
597  QualType Ty);
598 
599  /// Get the state and region whose binding this region \p R corresponds to.
600  ///
601  /// If there is no lazy binding for \p R, the returned value will have a null
602  /// \c second. Note that a null pointer can represents a valid Store.
603  std::pair<Store, const SubRegion *>
604  findLazyBinding(RegionBindingsConstRef B, const SubRegion *R,
605  const SubRegion *originalRegion);
606 
607  /// Returns the cached set of interesting SVals contained within a lazy
608  /// binding.
609  ///
610  /// The precise value of "interesting" is determined for the purposes of
611  /// RegionStore's internal analysis. It must always contain all regions and
612  /// symbols, but may omit constants and other kinds of SVal.
613  const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV);
614 
615  //===------------------------------------------------------------------===//
616  // State pruning.
617  //===------------------------------------------------------------------===//
618 
619  /// removeDeadBindings - Scans the RegionStore of 'state' for dead values.
620  /// It returns a new Store with these values removed.
621  StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
622  SymbolReaper& SymReaper) override;
623 
624  //===------------------------------------------------------------------===//
625  // Region "extents".
626  //===------------------------------------------------------------------===//
627 
628  // FIXME: This method will soon be eliminated; see the note in Store.h.
629  DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state,
630  const MemRegion* R,
631  QualType EleTy) override;
632 
633  //===------------------------------------------------------------------===//
634  // Utility methods.
635  //===------------------------------------------------------------------===//
636 
637  RegionBindingsRef getRegionBindings(Store store) const {
638  llvm::PointerIntPair<Store, 1, bool> Ptr;
639  Ptr.setFromOpaqueValue(const_cast<void *>(store));
640  return RegionBindingsRef(
641  CBFactory,
642  static_cast<const RegionBindings::TreeTy *>(Ptr.getPointer()),
643  RBFactory.getTreeFactory(),
644  Ptr.getInt());
645  }
646 
647  void printJson(raw_ostream &Out, Store S, const char *NL = "\n",
648  unsigned int Space = 0, bool IsDot = false) const override;
649 
650  void iterBindings(Store store, BindingsHandler& f) override {
651  RegionBindingsRef B = getRegionBindings(store);
652  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
653  const ClusterBindings &Cluster = I.getData();
654  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
655  CI != CE; ++CI) {
656  const BindingKey &K = CI.getKey();
657  if (!K.isDirect())
658  continue;
659  if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) {
660  // FIXME: Possibly incorporate the offset?
661  if (!f.HandleBinding(*this, store, R, CI.getData()))
662  return;
663  }
664  }
665  }
666  }
667 };
668 
669 } // end anonymous namespace
670 
671 //===----------------------------------------------------------------------===//
672 // RegionStore creation.
673 //===----------------------------------------------------------------------===//
674 
675 std::unique_ptr<StoreManager>
677  RegionStoreFeatures F = maximal_features_tag();
678  return std::make_unique<RegionStoreManager>(StMgr, F);
679 }
680 
681 std::unique_ptr<StoreManager>
683  RegionStoreFeatures F = minimal_features_tag();
684  F.enableFields(true);
685  return std::make_unique<RegionStoreManager>(StMgr, F);
686 }
687 
688 
689 //===----------------------------------------------------------------------===//
690 // Region Cluster analysis.
691 //===----------------------------------------------------------------------===//
692 
693 namespace {
694 /// Used to determine which global regions are automatically included in the
695 /// initial worklist of a ClusterAnalysis.
697  /// Don't include any global regions.
698  GFK_None,
699  /// Only include system globals.
700  GFK_SystemOnly,
701  /// Include all global regions.
702  GFK_All
703 };
704 
705 template <typename DERIVED>
706 class ClusterAnalysis {
707 protected:
708  typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap;
709  typedef const MemRegion * WorkListElement;
710  typedef SmallVector<WorkListElement, 10> WorkList;
711 
712  llvm::SmallPtrSet<const ClusterBindings *, 16> Visited;
713 
714  WorkList WL;
715 
716  RegionStoreManager &RM;
717  ASTContext &Ctx;
718  SValBuilder &svalBuilder;
719 
720  RegionBindingsRef B;
721 
722 
723 protected:
724  const ClusterBindings *getCluster(const MemRegion *R) {
725  return B.lookup(R);
726  }
727 
728  /// Returns true if all clusters in the given memspace should be initially
729  /// included in the cluster analysis. Subclasses may provide their
730  /// own implementation.
731  bool includeEntireMemorySpace(const MemRegion *Base) {
732  return false;
733  }
734 
735 public:
736  ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr,
737  RegionBindingsRef b)
738  : RM(rm), Ctx(StateMgr.getContext()),
739  svalBuilder(StateMgr.getSValBuilder()), B(std::move(b)) {}
740 
741  RegionBindingsRef getRegionBindings() const { return B; }
742 
743  bool isVisited(const MemRegion *R) {
744  return Visited.count(getCluster(R));
745  }
746 
747  void GenerateClusters() {
748  // Scan the entire set of bindings and record the region clusters.
749  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end();
750  RI != RE; ++RI){
751  const MemRegion *Base = RI.getKey();
752 
753  const ClusterBindings &Cluster = RI.getData();
754  assert(!Cluster.isEmpty() && "Empty clusters should be removed");
755  static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster);
756 
757  // If the base's memspace should be entirely invalidated, add the cluster
758  // to the workspace up front.
759  if (static_cast<DERIVED*>(this)->includeEntireMemorySpace(Base))
760  AddToWorkList(WorkListElement(Base), &Cluster);
761  }
762  }
763 
764  bool AddToWorkList(WorkListElement E, const ClusterBindings *C) {
765  if (C && !Visited.insert(C).second)
766  return false;
767  WL.push_back(E);
768  return true;
769  }
770 
771  bool AddToWorkList(const MemRegion *R) {
772  return static_cast<DERIVED*>(this)->AddToWorkList(R);
773  }
774 
775  void RunWorkList() {
776  while (!WL.empty()) {
777  WorkListElement E = WL.pop_back_val();
778  const MemRegion *BaseR = E;
779 
780  static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR));
781  }
782  }
783 
784  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {}
785  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {}
786 
787  void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C,
788  bool Flag) {
789  static_cast<DERIVED*>(this)->VisitCluster(BaseR, C);
790  }
791 };
792 }
793 
794 //===----------------------------------------------------------------------===//
795 // Binding invalidation.
796 //===----------------------------------------------------------------------===//
797 
798 bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R,
799  ScanReachableSymbols &Callbacks) {
800  assert(R == R->getBaseRegion() && "Should only be called for base regions");
801  RegionBindingsRef B = getRegionBindings(S);
802  const ClusterBindings *Cluster = B.lookup(R);
803 
804  if (!Cluster)
805  return true;
806 
807  for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end();
808  RI != RE; ++RI) {
809  if (!Callbacks.scan(RI.getData()))
810  return false;
811  }
812 
813  return true;
814 }
815 
816 static inline bool isUnionField(const FieldRegion *FR) {
817  return FR->getDecl()->getParent()->isUnion();
818 }
819 
821 
822 static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) {
823  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
824 
825  const MemRegion *Base = K.getConcreteOffsetRegion();
826  const MemRegion *R = K.getRegion();
827 
828  while (R != Base) {
829  if (const FieldRegion *FR = dyn_cast<FieldRegion>(R))
830  if (!isUnionField(FR))
831  Fields.push_back(FR->getDecl());
832 
833  R = cast<SubRegion>(R)->getSuperRegion();
834  }
835 }
836 
837 static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) {
838  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
839 
840  if (Fields.empty())
841  return true;
842 
843  FieldVector FieldsInBindingKey;
844  getSymbolicOffsetFields(K, FieldsInBindingKey);
845 
846  ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size();
847  if (Delta >= 0)
848  return std::equal(FieldsInBindingKey.begin() + Delta,
849  FieldsInBindingKey.end(),
850  Fields.begin());
851  else
852  return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(),
853  Fields.begin() - Delta);
854 }
855 
856 /// Collects all bindings in \p Cluster that may refer to bindings within
857 /// \p Top.
858 ///
859 /// Each binding is a pair whose \c first is the key (a BindingKey) and whose
860 /// \c second is the value (an SVal).
861 ///
862 /// The \p IncludeAllDefaultBindings parameter specifies whether to include
863 /// default bindings that may extend beyond \p Top itself, e.g. if \p Top is
864 /// an aggregate within a larger aggregate with a default binding.
865 static void
867  SValBuilder &SVB, const ClusterBindings &Cluster,
868  const SubRegion *Top, BindingKey TopKey,
869  bool IncludeAllDefaultBindings) {
870  FieldVector FieldsInSymbolicSubregions;
871  if (TopKey.hasSymbolicOffset()) {
872  getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions);
873  Top = TopKey.getConcreteOffsetRegion();
874  TopKey = BindingKey::Make(Top, BindingKey::Default);
875  }
876 
877  // Find the length (in bits) of the region being invalidated.
878  uint64_t Length = UINT64_MAX;
879  SVal Extent = Top->getExtent(SVB);
880  if (Optional<nonloc::ConcreteInt> ExtentCI =
881  Extent.getAs<nonloc::ConcreteInt>()) {
882  const llvm::APSInt &ExtentInt = ExtentCI->getValue();
883  assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned());
884  // Extents are in bytes but region offsets are in bits. Be careful!
885  Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth();
886  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) {
887  if (FR->getDecl()->isBitField())
888  Length = FR->getDecl()->getBitWidthValue(SVB.getContext());
889  }
890 
891  for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end();
892  I != E; ++I) {
893  BindingKey NextKey = I.getKey();
894  if (NextKey.getRegion() == TopKey.getRegion()) {
895  // FIXME: This doesn't catch the case where we're really invalidating a
896  // region with a symbolic offset. Example:
897  // R: points[i].y
898  // Next: points[0].x
899 
900  if (NextKey.getOffset() > TopKey.getOffset() &&
901  NextKey.getOffset() - TopKey.getOffset() < Length) {
902  // Case 1: The next binding is inside the region we're invalidating.
903  // Include it.
904  Bindings.push_back(*I);
905 
906  } else if (NextKey.getOffset() == TopKey.getOffset()) {
907  // Case 2: The next binding is at the same offset as the region we're
908  // invalidating. In this case, we need to leave default bindings alone,
909  // since they may be providing a default value for a regions beyond what
910  // we're invalidating.
911  // FIXME: This is probably incorrect; consider invalidating an outer
912  // struct whose first field is bound to a LazyCompoundVal.
913  if (IncludeAllDefaultBindings || NextKey.isDirect())
914  Bindings.push_back(*I);
915  }
916 
917  } else if (NextKey.hasSymbolicOffset()) {
918  const MemRegion *Base = NextKey.getConcreteOffsetRegion();
919  if (Top->isSubRegionOf(Base) && Top != Base) {
920  // Case 3: The next key is symbolic and we just changed something within
921  // its concrete region. We don't know if the binding is still valid, so
922  // we'll be conservative and include it.
923  if (IncludeAllDefaultBindings || NextKey.isDirect())
924  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
925  Bindings.push_back(*I);
926  } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) {
927  // Case 4: The next key is symbolic, but we changed a known
928  // super-region. In this case the binding is certainly included.
929  if (BaseSR->isSubRegionOf(Top))
930  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
931  Bindings.push_back(*I);
932  }
933  }
934  }
935 }
936 
937 static void
939  SValBuilder &SVB, const ClusterBindings &Cluster,
940  const SubRegion *Top, bool IncludeAllDefaultBindings) {
941  collectSubRegionBindings(Bindings, SVB, Cluster, Top,
943  IncludeAllDefaultBindings);
944 }
945 
946 RegionBindingsRef
947 RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B,
948  const SubRegion *Top) {
949  BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default);
950  const MemRegion *ClusterHead = TopKey.getBaseRegion();
951 
952  if (Top == ClusterHead) {
953  // We can remove an entire cluster's bindings all in one go.
954  return B.remove(Top);
955  }
956 
957  const ClusterBindings *Cluster = B.lookup(ClusterHead);
958  if (!Cluster) {
959  // If we're invalidating a region with a symbolic offset, we need to make
960  // sure we don't treat the base region as uninitialized anymore.
961  if (TopKey.hasSymbolicOffset()) {
962  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
963  return B.addBinding(Concrete, BindingKey::Default, UnknownVal());
964  }
965  return B;
966  }
967 
969  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey,
970  /*IncludeAllDefaultBindings=*/false);
971 
972  ClusterBindingsRef Result(*Cluster, CBFactory);
973  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
974  E = Bindings.end();
975  I != E; ++I)
976  Result = Result.remove(I->first);
977 
978  // If we're invalidating a region with a symbolic offset, we need to make sure
979  // we don't treat the base region as uninitialized anymore.
980  // FIXME: This isn't very precise; see the example in
981  // collectSubRegionBindings.
982  if (TopKey.hasSymbolicOffset()) {
983  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
984  Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default),
985  UnknownVal());
986  }
987 
988  if (Result.isEmpty())
989  return B.remove(ClusterHead);
990  return B.add(ClusterHead, Result.asImmutableMap());
991 }
992 
993 namespace {
994 class InvalidateRegionsWorker : public ClusterAnalysis<InvalidateRegionsWorker>
995 {
996  const Expr *Ex;
997  unsigned Count;
998  const LocationContext *LCtx;
999  InvalidatedSymbols &IS;
1000  RegionAndSymbolInvalidationTraits &ITraits;
1002  GlobalsFilterKind GlobalsFilter;
1003 public:
1004  InvalidateRegionsWorker(RegionStoreManager &rm,
1005  ProgramStateManager &stateMgr,
1006  RegionBindingsRef b,
1007  const Expr *ex, unsigned count,
1008  const LocationContext *lctx,
1009  InvalidatedSymbols &is,
1010  RegionAndSymbolInvalidationTraits &ITraitsIn,
1012  GlobalsFilterKind GFK)
1013  : ClusterAnalysis<InvalidateRegionsWorker>(rm, stateMgr, b),
1014  Ex(ex), Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r),
1015  GlobalsFilter(GFK) {}
1016 
1017  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
1018  void VisitBinding(SVal V);
1019 
1020  using ClusterAnalysis::AddToWorkList;
1021 
1022  bool AddToWorkList(const MemRegion *R);
1023 
1024  /// Returns true if all clusters in the memory space for \p Base should be
1025  /// be invalidated.
1026  bool includeEntireMemorySpace(const MemRegion *Base);
1027 
1028  /// Returns true if the memory space of the given region is one of the global
1029  /// regions specially included at the start of invalidation.
1030  bool isInitiallyIncludedGlobalRegion(const MemRegion *R);
1031 };
1032 }
1033 
1034 bool InvalidateRegionsWorker::AddToWorkList(const MemRegion *R) {
1035  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1037  const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion();
1038  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
1039 }
1040 
1041 void InvalidateRegionsWorker::VisitBinding(SVal V) {
1042  // A symbol? Mark it touched by the invalidation.
1043  if (SymbolRef Sym = V.getAsSymbol())
1044  IS.insert(Sym);
1045 
1046  if (const MemRegion *R = V.getAsRegion()) {
1047  AddToWorkList(R);
1048  return;
1049  }
1050 
1051  // Is it a LazyCompoundVal? All references get invalidated as well.
1053  V.getAs<nonloc::LazyCompoundVal>()) {
1054 
1055  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
1056 
1057  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
1058  E = Vals.end();
1059  I != E; ++I)
1060  VisitBinding(*I);
1061 
1062  return;
1063  }
1064 }
1065 
1066 void InvalidateRegionsWorker::VisitCluster(const MemRegion *baseR,
1067  const ClusterBindings *C) {
1068 
1069  bool PreserveRegionsContents =
1070  ITraits.hasTrait(baseR,
1072 
1073  if (C) {
1074  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I)
1075  VisitBinding(I.getData());
1076 
1077  // Invalidate regions contents.
1078  if (!PreserveRegionsContents)
1079  B = B.remove(baseR);
1080  }
1081 
1082  if (const auto *TO = dyn_cast<TypedValueRegion>(baseR)) {
1083  if (const auto *RD = TO->getValueType()->getAsCXXRecordDecl()) {
1084 
1085  // Lambdas can affect all static local variables without explicitly
1086  // capturing those.
1087  // We invalidate all static locals referenced inside the lambda body.
1088  if (RD->isLambda() && RD->getLambdaCallOperator()->getBody()) {
1089  using namespace ast_matchers;
1090 
1091  const char *DeclBind = "DeclBind";
1093  to(varDecl(hasStaticStorageDuration()).bind(DeclBind)))));
1094  auto Matches =
1095  match(RefToStatic, *RD->getLambdaCallOperator()->getBody(),
1096  RD->getASTContext());
1097 
1098  for (BoundNodes &Match : Matches) {
1099  auto *VD = Match.getNodeAs<VarDecl>(DeclBind);
1100  const VarRegion *ToInvalidate =
1101  RM.getRegionManager().getVarRegion(VD, LCtx);
1102  AddToWorkList(ToInvalidate);
1103  }
1104  }
1105  }
1106  }
1107 
1108  // BlockDataRegion? If so, invalidate captured variables that are passed
1109  // by reference.
1110  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) {
1111  for (BlockDataRegion::referenced_vars_iterator
1112  BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ;
1113  BI != BE; ++BI) {
1114  const VarRegion *VR = BI.getCapturedRegion();
1115  const VarDecl *VD = VR->getDecl();
1116  if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage()) {
1117  AddToWorkList(VR);
1118  }
1119  else if (Loc::isLocType(VR->getValueType())) {
1120  // Map the current bindings to a Store to retrieve the value
1121  // of the binding. If that binding itself is a region, we should
1122  // invalidate that region. This is because a block may capture
1123  // a pointer value, but the thing pointed by that pointer may
1124  // get invalidated.
1125  SVal V = RM.getBinding(B, loc::MemRegionVal(VR));
1126  if (Optional<Loc> L = V.getAs<Loc>()) {
1127  if (const MemRegion *LR = L->getAsRegion())
1128  AddToWorkList(LR);
1129  }
1130  }
1131  }
1132  return;
1133  }
1134 
1135  // Symbolic region?
1136  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR))
1137  IS.insert(SR->getSymbol());
1138 
1139  // Nothing else should be done in the case when we preserve regions context.
1140  if (PreserveRegionsContents)
1141  return;
1142 
1143  // Otherwise, we have a normal data region. Record that we touched the region.
1144  if (Regions)
1145  Regions->push_back(baseR);
1146 
1147  if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) {
1148  // Invalidate the region by setting its default value to
1149  // conjured symbol. The type of the symbol is irrelevant.
1150  DefinedOrUnknownSVal V =
1151  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
1152  B = B.addBinding(baseR, BindingKey::Default, V);
1153  return;
1154  }
1155 
1156  if (!baseR->isBoundable())
1157  return;
1158 
1159  const TypedValueRegion *TR = cast<TypedValueRegion>(baseR);
1160  QualType T = TR->getValueType();
1161 
1162  if (isInitiallyIncludedGlobalRegion(baseR)) {
1163  // If the region is a global and we are invalidating all globals,
1164  // erasing the entry is good enough. This causes all globals to be lazily
1165  // symbolicated from the same base symbol.
1166  return;
1167  }
1168 
1169  if (T->isRecordType()) {
1170  // Invalidate the region by setting its default value to
1171  // conjured symbol. The type of the symbol is irrelevant.
1172  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1173  Ctx.IntTy, Count);
1174  B = B.addBinding(baseR, BindingKey::Default, V);
1175  return;
1176  }
1177 
1178  if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
1179  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1180  baseR,
1182 
1183  if (doNotInvalidateSuperRegion) {
1184  // We are not doing blank invalidation of the whole array region so we
1185  // have to manually invalidate each elements.
1186  Optional<uint64_t> NumElements;
1187 
1188  // Compute lower and upper offsets for region within array.
1189  if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT))
1190  NumElements = CAT->getSize().getZExtValue();
1191  if (!NumElements) // We are not dealing with a constant size array
1192  goto conjure_default;
1193  QualType ElementTy = AT->getElementType();
1194  uint64_t ElemSize = Ctx.getTypeSize(ElementTy);
1195  const RegionOffset &RO = baseR->getAsOffset();
1196  const MemRegion *SuperR = baseR->getBaseRegion();
1197  if (RO.hasSymbolicOffset()) {
1198  // If base region has a symbolic offset,
1199  // we revert to invalidating the super region.
1200  if (SuperR)
1201  AddToWorkList(SuperR);
1202  goto conjure_default;
1203  }
1204 
1205  uint64_t LowerOffset = RO.getOffset();
1206  uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize;
1207  bool UpperOverflow = UpperOffset < LowerOffset;
1208 
1209  // Invalidate regions which are within array boundaries,
1210  // or have a symbolic offset.
1211  if (!SuperR)
1212  goto conjure_default;
1213 
1214  const ClusterBindings *C = B.lookup(SuperR);
1215  if (!C)
1216  goto conjure_default;
1217 
1218  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E;
1219  ++I) {
1220  const BindingKey &BK = I.getKey();
1221  Optional<uint64_t> ROffset =
1222  BK.hasSymbolicOffset() ? Optional<uint64_t>() : BK.getOffset();
1223 
1224  // Check offset is not symbolic and within array's boundaries.
1225  // Handles arrays of 0 elements and of 0-sized elements as well.
1226  if (!ROffset ||
1227  ((*ROffset >= LowerOffset && *ROffset < UpperOffset) ||
1228  (UpperOverflow &&
1229  (*ROffset >= LowerOffset || *ROffset < UpperOffset)) ||
1230  (LowerOffset == UpperOffset && *ROffset == LowerOffset))) {
1231  B = B.removeBinding(I.getKey());
1232  // Bound symbolic regions need to be invalidated for dead symbol
1233  // detection.
1234  SVal V = I.getData();
1235  const MemRegion *R = V.getAsRegion();
1236  if (R && isa<SymbolicRegion>(R))
1237  VisitBinding(V);
1238  }
1239  }
1240  }
1241  conjure_default:
1242  // Set the default value of the array to conjured symbol.
1243  DefinedOrUnknownSVal V =
1244  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1245  AT->getElementType(), Count);
1246  B = B.addBinding(baseR, BindingKey::Default, V);
1247  return;
1248  }
1249 
1250  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1251  T,Count);
1252  assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
1253  B = B.addBinding(baseR, BindingKey::Direct, V);
1254 }
1255 
1256 bool InvalidateRegionsWorker::isInitiallyIncludedGlobalRegion(
1257  const MemRegion *R) {
1258  switch (GlobalsFilter) {
1259  case GFK_None:
1260  return false;
1261  case GFK_SystemOnly:
1262  return isa<GlobalSystemSpaceRegion>(R->getMemorySpace());
1263  case GFK_All:
1264  return isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace());
1265  }
1266 
1267  llvm_unreachable("unknown globals filter");
1268 }
1269 
1270 bool InvalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) {
1271  if (isInitiallyIncludedGlobalRegion(Base))
1272  return true;
1273 
1274  const MemSpaceRegion *MemSpace = Base->getMemorySpace();
1275  return ITraits.hasTrait(MemSpace,
1277 }
1278 
1279 RegionBindingsRef
1280 RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K,
1281  const Expr *Ex,
1282  unsigned Count,
1283  const LocationContext *LCtx,
1284  RegionBindingsRef B,
1285  InvalidatedRegions *Invalidated) {
1286  // Bind the globals memory space to a new symbol that we will use to derive
1287  // the bindings for all globals.
1288  const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K);
1289  SVal V = svalBuilder.conjureSymbolVal(/* symbolTag = */ (const void*) GS, Ex, LCtx,
1290  /* type does not matter */ Ctx.IntTy,
1291  Count);
1292 
1293  B = B.removeBinding(GS)
1294  .addBinding(BindingKey::Make(GS, BindingKey::Default), V);
1295 
1296  // Even if there are no bindings in the global scope, we still need to
1297  // record that we touched it.
1298  if (Invalidated)
1299  Invalidated->push_back(GS);
1300 
1301  return B;
1302 }
1303 
1304 void RegionStoreManager::populateWorkList(InvalidateRegionsWorker &W,
1305  ArrayRef<SVal> Values,
1306  InvalidatedRegions *TopLevelRegions) {
1307  for (ArrayRef<SVal>::iterator I = Values.begin(),
1308  E = Values.end(); I != E; ++I) {
1309  SVal V = *I;
1311  V.getAs<nonloc::LazyCompoundVal>()) {
1312 
1313  const SValListTy &Vals = getInterestingValues(*LCS);
1314 
1315  for (SValListTy::const_iterator I = Vals.begin(),
1316  E = Vals.end(); I != E; ++I) {
1317  // Note: the last argument is false here because these are
1318  // non-top-level regions.
1319  if (const MemRegion *R = (*I).getAsRegion())
1320  W.AddToWorkList(R);
1321  }
1322  continue;
1323  }
1324 
1325  if (const MemRegion *R = V.getAsRegion()) {
1326  if (TopLevelRegions)
1327  TopLevelRegions->push_back(R);
1328  W.AddToWorkList(R);
1329  continue;
1330  }
1331  }
1332 }
1333 
1334 StoreRef
1335 RegionStoreManager::invalidateRegions(Store store,
1336  ArrayRef<SVal> Values,
1337  const Expr *Ex, unsigned Count,
1338  const LocationContext *LCtx,
1339  const CallEvent *Call,
1340  InvalidatedSymbols &IS,
1341  RegionAndSymbolInvalidationTraits &ITraits,
1342  InvalidatedRegions *TopLevelRegions,
1343  InvalidatedRegions *Invalidated) {
1344  GlobalsFilterKind GlobalsFilter;
1345  if (Call) {
1346  if (Call->isInSystemHeader())
1347  GlobalsFilter = GFK_SystemOnly;
1348  else
1349  GlobalsFilter = GFK_All;
1350  } else {
1351  GlobalsFilter = GFK_None;
1352  }
1353 
1354  RegionBindingsRef B = getRegionBindings(store);
1355  InvalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, ITraits,
1356  Invalidated, GlobalsFilter);
1357 
1358  // Scan the bindings and generate the clusters.
1359  W.GenerateClusters();
1360 
1361  // Add the regions to the worklist.
1362  populateWorkList(W, Values, TopLevelRegions);
1363 
1364  W.RunWorkList();
1365 
1366  // Return the new bindings.
1367  B = W.getRegionBindings();
1368 
1369  // For calls, determine which global regions should be invalidated and
1370  // invalidate them. (Note that function-static and immutable globals are never
1371  // invalidated by this.)
1372  // TODO: This could possibly be more precise with modules.
1373  switch (GlobalsFilter) {
1374  case GFK_All:
1375  B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind,
1376  Ex, Count, LCtx, B, Invalidated);
1377  LLVM_FALLTHROUGH;
1378  case GFK_SystemOnly:
1379  B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
1380  Ex, Count, LCtx, B, Invalidated);
1381  LLVM_FALLTHROUGH;
1382  case GFK_None:
1383  break;
1384  }
1385 
1386  return StoreRef(B.asStore(), *this);
1387 }
1388 
1389 //===----------------------------------------------------------------------===//
1390 // Extents for regions.
1391 //===----------------------------------------------------------------------===//
1392 
1393 DefinedOrUnknownSVal
1394 RegionStoreManager::getSizeInElements(ProgramStateRef state,
1395  const MemRegion *R,
1396  QualType EleTy) {
1397  SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder);
1398  const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size);
1399  if (!SizeInt)
1400  return UnknownVal();
1401 
1402  CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue());
1403 
1404  if (Ctx.getAsVariableArrayType(EleTy)) {
1405  // FIXME: We need to track extra state to properly record the size
1406  // of VLAs. Returning UnknownVal here, however, is a stop-gap so that
1407  // we don't have a divide-by-zero below.
1408  return UnknownVal();
1409  }
1410 
1411  CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy);
1412 
1413  // If a variable is reinterpreted as a type that doesn't fit into a larger
1414  // type evenly, round it down.
1415  // This is a signed value, since it's used in arithmetic with signed indices.
1416  return svalBuilder.makeIntVal(RegionSize / EleSize,
1417  svalBuilder.getArrayIndexType());
1418 }
1419 
1420 //===----------------------------------------------------------------------===//
1421 // Location and region casting.
1422 //===----------------------------------------------------------------------===//
1423 
1424 /// ArrayToPointer - Emulates the "decay" of an array to a pointer
1425 /// type. 'Array' represents the lvalue of the array being decayed
1426 /// to a pointer, and the returned SVal represents the decayed
1427 /// version of that lvalue (i.e., a pointer to the first element of
1428 /// the array). This is called by ExprEngine when evaluating casts
1429 /// from arrays to pointers.
1430 SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) {
1431  if (Array.getAs<loc::ConcreteInt>())
1432  return Array;
1433 
1434  if (!Array.getAs<loc::MemRegionVal>())
1435  return UnknownVal();
1436 
1437  const SubRegion *R =
1438  cast<SubRegion>(Array.castAs<loc::MemRegionVal>().getRegion());
1439  NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
1440  return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, R, Ctx));
1441 }
1442 
1443 //===----------------------------------------------------------------------===//
1444 // Loading values from regions.
1445 //===----------------------------------------------------------------------===//
1446 
1447 SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) {
1448  assert(!L.getAs<UnknownVal>() && "location unknown");
1449  assert(!L.getAs<UndefinedVal>() && "location undefined");
1450 
1451  // For access to concrete addresses, return UnknownVal. Checks
1452  // for null dereferences (and similar errors) are done by checkers, not
1453  // the Store.
1454  // FIXME: We can consider lazily symbolicating such memory, but we really
1455  // should defer this when we can reason easily about symbolicating arrays
1456  // of bytes.
1457  if (L.getAs<loc::ConcreteInt>()) {
1458  return UnknownVal();
1459  }
1460  if (!L.getAs<loc::MemRegionVal>()) {
1461  return UnknownVal();
1462  }
1463 
1464  const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion();
1465 
1466  if (isa<BlockDataRegion>(MR)) {
1467  return UnknownVal();
1468  }
1469 
1470  if (!isa<TypedValueRegion>(MR)) {
1471  if (T.isNull()) {
1472  if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
1473  T = TR->getLocationType()->getPointeeType();
1474  else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1475  T = SR->getSymbol()->getType()->getPointeeType();
1476  }
1477  assert(!T.isNull() && "Unable to auto-detect binding type!");
1478  assert(!T->isVoidType() && "Attempting to dereference a void pointer!");
1479  MR = GetElementZeroRegion(cast<SubRegion>(MR), T);
1480  } else {
1481  T = cast<TypedValueRegion>(MR)->getValueType();
1482  }
1483 
1484  // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
1485  // instead of 'Loc', and have the other Loc cases handled at a higher level.
1486  const TypedValueRegion *R = cast<TypedValueRegion>(MR);
1487  QualType RTy = R->getValueType();
1488 
1489  // FIXME: we do not yet model the parts of a complex type, so treat the
1490  // whole thing as "unknown".
1491  if (RTy->isAnyComplexType())
1492  return UnknownVal();
1493 
1494  // FIXME: We should eventually handle funny addressing. e.g.:
1495  //
1496  // int x = ...;
1497  // int *p = &x;
1498  // char *q = (char*) p;
1499  // char c = *q; // returns the first byte of 'x'.
1500  //
1501  // Such funny addressing will occur due to layering of regions.
1502  if (RTy->isStructureOrClassType())
1503  return getBindingForStruct(B, R);
1504 
1505  // FIXME: Handle unions.
1506  if (RTy->isUnionType())
1507  return createLazyBinding(B, R);
1508 
1509  if (RTy->isArrayType()) {
1510  if (RTy->isConstantArrayType())
1511  return getBindingForArray(B, R);
1512  else
1513  return UnknownVal();
1514  }
1515 
1516  // FIXME: handle Vector types.
1517  if (RTy->isVectorType())
1518  return UnknownVal();
1519 
1520  if (const FieldRegion* FR = dyn_cast<FieldRegion>(R))
1521  return CastRetrievedVal(getBindingForField(B, FR), FR, T);
1522 
1523  if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
1524  // FIXME: Here we actually perform an implicit conversion from the loaded
1525  // value to the element type. Eventually we want to compose these values
1526  // more intelligently. For example, an 'element' can encompass multiple
1527  // bound regions (e.g., several bound bytes), or could be a subset of
1528  // a larger value.
1529  return CastRetrievedVal(getBindingForElement(B, ER), ER, T);
1530  }
1531 
1532  if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) {
1533  // FIXME: Here we actually perform an implicit conversion from the loaded
1534  // value to the ivar type. What we should model is stores to ivars
1535  // that blow past the extent of the ivar. If the address of the ivar is
1536  // reinterpretted, it is possible we stored a different value that could
1537  // fit within the ivar. Either we need to cast these when storing them
1538  // or reinterpret them lazily (as we do here).
1539  return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T);
1540  }
1541 
1542  if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
1543  // FIXME: Here we actually perform an implicit conversion from the loaded
1544  // value to the variable type. What we should model is stores to variables
1545  // that blow past the extent of the variable. If the address of the
1546  // variable is reinterpretted, it is possible we stored a different value
1547  // that could fit within the variable. Either we need to cast these when
1548  // storing them or reinterpret them lazily (as we do here).
1549  return CastRetrievedVal(getBindingForVar(B, VR), VR, T);
1550  }
1551 
1552  const SVal *V = B.lookup(R, BindingKey::Direct);
1553 
1554  // Check if the region has a binding.
1555  if (V)
1556  return *V;
1557 
1558  // The location does not have a bound value. This means that it has
1559  // the value it had upon its creation and/or entry to the analyzed
1560  // function/method. These are either symbolic values or 'undefined'.
1561  if (R->hasStackNonParametersStorage()) {
1562  // All stack variables are considered to have undefined values
1563  // upon creation. All heap allocated blocks are considered to
1564  // have undefined values as well unless they are explicitly bound
1565  // to specific values.
1566  return UndefinedVal();
1567  }
1568 
1569  // All other values are symbolic.
1570  return svalBuilder.getRegionValueSymbolVal(R);
1571 }
1572 
1573 static QualType getUnderlyingType(const SubRegion *R) {
1574  QualType RegionTy;
1575  if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R))
1576  RegionTy = TVR->getValueType();
1577 
1578  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1579  RegionTy = SR->getSymbol()->getType();
1580 
1581  return RegionTy;
1582 }
1583 
1584 /// Checks to see if store \p B has a lazy binding for region \p R.
1585 ///
1586 /// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected
1587 /// if there are additional bindings within \p R.
1588 ///
1589 /// Note that unlike RegionStoreManager::findLazyBinding, this will not search
1590 /// for lazy bindings for super-regions of \p R.
1592 getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B,
1593  const SubRegion *R, bool AllowSubregionBindings) {
1594  Optional<SVal> V = B.getDefaultBinding(R);
1595  if (!V)
1596  return None;
1597 
1598  Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>();
1599  if (!LCV)
1600  return None;
1601 
1602  // If the LCV is for a subregion, the types might not match, and we shouldn't
1603  // reuse the binding.
1604  QualType RegionTy = getUnderlyingType(R);
1605  if (!RegionTy.isNull() &&
1606  !RegionTy->isVoidPointerType()) {
1607  QualType SourceRegionTy = LCV->getRegion()->getValueType();
1608  if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy))
1609  return None;
1610  }
1611 
1612  if (!AllowSubregionBindings) {
1613  // If there are any other bindings within this region, we shouldn't reuse
1614  // the top-level binding.
1616  collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R,
1617  /*IncludeAllDefaultBindings=*/true);
1618  if (Bindings.size() > 1)
1619  return None;
1620  }
1621 
1622  return *LCV;
1623 }
1624 
1625 
1626 std::pair<Store, const SubRegion *>
1627 RegionStoreManager::findLazyBinding(RegionBindingsConstRef B,
1628  const SubRegion *R,
1629  const SubRegion *originalRegion) {
1630  if (originalRegion != R) {
1632  getExistingLazyBinding(svalBuilder, B, R, true))
1633  return std::make_pair(V->getStore(), V->getRegion());
1634  }
1635 
1636  typedef std::pair<Store, const SubRegion *> StoreRegionPair;
1637  StoreRegionPair Result = StoreRegionPair();
1638 
1639  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
1640  Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()),
1641  originalRegion);
1642 
1643  if (Result.second)
1644  Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second);
1645 
1646  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
1647  Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()),
1648  originalRegion);
1649 
1650  if (Result.second)
1651  Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second);
1652 
1653  } else if (const CXXBaseObjectRegion *BaseReg =
1654  dyn_cast<CXXBaseObjectRegion>(R)) {
1655  // C++ base object region is another kind of region that we should blast
1656  // through to look for lazy compound value. It is like a field region.
1657  Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()),
1658  originalRegion);
1659 
1660  if (Result.second)
1661  Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg,
1662  Result.second);
1663  }
1664 
1665  return Result;
1666 }
1667 
1668 SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B,
1669  const ElementRegion* R) {
1670  // We do not currently model bindings of the CompoundLiteralregion.
1671  if (isa<CompoundLiteralRegion>(R->getBaseRegion()))
1672  return UnknownVal();
1673 
1674  // Check if the region has a binding.
1675  if (const Optional<SVal> &V = B.getDirectBinding(R))
1676  return *V;
1677 
1678  const MemRegion* superR = R->getSuperRegion();
1679 
1680  // Check if the region is an element region of a string literal.
1681  if (const StringRegion *StrR = dyn_cast<StringRegion>(superR)) {
1682  // FIXME: Handle loads from strings where the literal is treated as
1683  // an integer, e.g., *((unsigned int*)"hello")
1684  QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType();
1685  if (!Ctx.hasSameUnqualifiedType(T, R->getElementType()))
1686  return UnknownVal();
1687 
1688  const StringLiteral *Str = StrR->getStringLiteral();
1689  SVal Idx = R->getIndex();
1690  if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) {
1691  int64_t i = CI->getValue().getSExtValue();
1692  // Abort on string underrun. This can be possible by arbitrary
1693  // clients of getBindingForElement().
1694  if (i < 0)
1695  return UndefinedVal();
1696  int64_t length = Str->getLength();
1697  // Technically, only i == length is guaranteed to be null.
1698  // However, such overflows should be caught before reaching this point;
1699  // the only time such an access would be made is if a string literal was
1700  // used to initialize a larger array.
1701  char c = (i >= length) ? '\0' : Str->getCodeUnit(i);
1702  return svalBuilder.makeIntVal(c, T);
1703  }
1704  } else if (const VarRegion *VR = dyn_cast<VarRegion>(superR)) {
1705  // Check if the containing array has an initialized value that we can trust.
1706  // We can trust a const value or a value of a global initializer in main().
1707  const VarDecl *VD = VR->getDecl();
1708  if (VD->getType().isConstQualified() ||
1709  R->getElementType().isConstQualified() ||
1710  (B.isMainAnalysis() && VD->hasGlobalStorage())) {
1711  if (const Expr *Init = VD->getAnyInitializer()) {
1712  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1713  // The array index has to be known.
1714  if (auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) {
1715  int64_t i = CI->getValue().getSExtValue();
1716  // If it is known that the index is out of bounds, we can return
1717  // an undefined value.
1718  if (i < 0)
1719  return UndefinedVal();
1720 
1721  if (auto CAT = Ctx.getAsConstantArrayType(VD->getType()))
1722  if (CAT->getSize().sle(i))
1723  return UndefinedVal();
1724 
1725  // If there is a list, but no init, it must be zero.
1726  if (i >= InitList->getNumInits())
1727  return svalBuilder.makeZeroVal(R->getElementType());
1728 
1729  if (const Expr *ElemInit = InitList->getInit(i))
1730  if (Optional<SVal> V = svalBuilder.getConstantVal(ElemInit))
1731  return *V;
1732  }
1733  }
1734  }
1735  }
1736  }
1737 
1738  // Check for loads from a code text region. For such loads, just give up.
1739  if (isa<CodeTextRegion>(superR))
1740  return UnknownVal();
1741 
1742  // Handle the case where we are indexing into a larger scalar object.
1743  // For example, this handles:
1744  // int x = ...
1745  // char *y = &x;
1746  // return *y;
1747  // FIXME: This is a hack, and doesn't do anything really intelligent yet.
1748  const RegionRawOffset &O = R->getAsArrayOffset();
1749 
1750  // If we cannot reason about the offset, return an unknown value.
1751  if (!O.getRegion())
1752  return UnknownVal();
1753 
1754  if (const TypedValueRegion *baseR =
1755  dyn_cast_or_null<TypedValueRegion>(O.getRegion())) {
1756  QualType baseT = baseR->getValueType();
1757  if (baseT->isScalarType()) {
1758  QualType elemT = R->getElementType();
1759  if (elemT->isScalarType()) {
1760  if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) {
1761  if (const Optional<SVal> &V = B.getDirectBinding(superR)) {
1762  if (SymbolRef parentSym = V->getAsSymbol())
1763  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1764 
1765  if (V->isUnknownOrUndef())
1766  return *V;
1767  // Other cases: give up. We are indexing into a larger object
1768  // that has some value, but we don't know how to handle that yet.
1769  return UnknownVal();
1770  }
1771  }
1772  }
1773  }
1774  }
1775  return getBindingForFieldOrElementCommon(B, R, R->getElementType());
1776 }
1777 
1778 SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B,
1779  const FieldRegion* R) {
1780 
1781  // Check if the region has a binding.
1782  if (const Optional<SVal> &V = B.getDirectBinding(R))
1783  return *V;
1784 
1785  // Is the field declared constant and has an in-class initializer?
1786  const FieldDecl *FD = R->getDecl();
1787  QualType Ty = FD->getType();
1788  if (Ty.isConstQualified())
1789  if (const Expr *Init = FD->getInClassInitializer())
1790  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1791  return *V;
1792 
1793  // If the containing record was initialized, try to get its constant value.
1794  const MemRegion* superR = R->getSuperRegion();
1795  if (const auto *VR = dyn_cast<VarRegion>(superR)) {
1796  const VarDecl *VD = VR->getDecl();
1797  QualType RecordVarTy = VD->getType();
1798  unsigned Index = FD->getFieldIndex();
1799  // Either the record variable or the field has an initializer that we can
1800  // trust. We trust initializers of constants and, additionally, respect
1801  // initializers of globals when analyzing main().
1802  if (RecordVarTy.isConstQualified() || Ty.isConstQualified() ||
1803  (B.isMainAnalysis() && VD->hasGlobalStorage()))
1804  if (const Expr *Init = VD->getAnyInitializer())
1805  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1806  if (Index < InitList->getNumInits()) {
1807  if (const Expr *FieldInit = InitList->getInit(Index))
1808  if (Optional<SVal> V = svalBuilder.getConstantVal(FieldInit))
1809  return *V;
1810  } else {
1811  return svalBuilder.makeZeroVal(Ty);
1812  }
1813  }
1814  }
1815 
1816  return getBindingForFieldOrElementCommon(B, R, Ty);
1817 }
1818 
1820 RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
1821  const MemRegion *superR,
1822  const TypedValueRegion *R,
1823  QualType Ty) {
1824 
1825  if (const Optional<SVal> &D = B.getDefaultBinding(superR)) {
1826  const SVal &val = D.getValue();
1827  if (SymbolRef parentSym = val.getAsSymbol())
1828  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1829 
1830  if (val.isZeroConstant())
1831  return svalBuilder.makeZeroVal(Ty);
1832 
1833  if (val.isUnknownOrUndef())
1834  return val;
1835 
1836  // Lazy bindings are usually handled through getExistingLazyBinding().
1837  // We should unify these two code paths at some point.
1838  if (val.getAs<nonloc::LazyCompoundVal>() ||
1839  val.getAs<nonloc::CompoundVal>())
1840  return val;
1841 
1842  llvm_unreachable("Unknown default value");
1843  }
1844 
1845  return None;
1846 }
1847 
1848 SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion,
1849  RegionBindingsRef LazyBinding) {
1850  SVal Result;
1851  if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion))
1852  Result = getBindingForElement(LazyBinding, ER);
1853  else
1854  Result = getBindingForField(LazyBinding,
1855  cast<FieldRegion>(LazyBindingRegion));
1856 
1857  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1858  // default value for /part/ of an aggregate from a default value for the
1859  // /entire/ aggregate. The most common case of this is when struct Outer
1860  // has as its first member a struct Inner, which is copied in from a stack
1861  // variable. In this case, even if the Outer's default value is symbolic, 0,
1862  // or unknown, it gets overridden by the Inner's default value of undefined.
1863  //
1864  // This is a general problem -- if the Inner is zero-initialized, the Outer
1865  // will now look zero-initialized. The proper way to solve this is with a
1866  // new version of RegionStore that tracks the extent of a binding as well
1867  // as the offset.
1868  //
1869  // This hack only takes care of the undefined case because that can very
1870  // quickly result in a warning.
1871  if (Result.isUndef())
1872  Result = UnknownVal();
1873 
1874  return Result;
1875 }
1876 
1877 SVal
1878 RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
1879  const TypedValueRegion *R,
1880  QualType Ty) {
1881 
1882  // At this point we have already checked in either getBindingForElement or
1883  // getBindingForField if 'R' has a direct binding.
1884 
1885  // Lazy binding?
1886  Store lazyBindingStore = nullptr;
1887  const SubRegion *lazyBindingRegion = nullptr;
1888  std::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R);
1889  if (lazyBindingRegion)
1890  return getLazyBinding(lazyBindingRegion,
1891  getRegionBindings(lazyBindingStore));
1892 
1893  // Record whether or not we see a symbolic index. That can completely
1894  // be out of scope of our lookup.
1895  bool hasSymbolicIndex = false;
1896 
1897  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1898  // default value for /part/ of an aggregate from a default value for the
1899  // /entire/ aggregate. The most common case of this is when struct Outer
1900  // has as its first member a struct Inner, which is copied in from a stack
1901  // variable. In this case, even if the Outer's default value is symbolic, 0,
1902  // or unknown, it gets overridden by the Inner's default value of undefined.
1903  //
1904  // This is a general problem -- if the Inner is zero-initialized, the Outer
1905  // will now look zero-initialized. The proper way to solve this is with a
1906  // new version of RegionStore that tracks the extent of a binding as well
1907  // as the offset.
1908  //
1909  // This hack only takes care of the undefined case because that can very
1910  // quickly result in a warning.
1911  bool hasPartialLazyBinding = false;
1912 
1913  const SubRegion *SR = R;
1914  while (SR) {
1915  const MemRegion *Base = SR->getSuperRegion();
1916  if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) {
1917  if (D->getAs<nonloc::LazyCompoundVal>()) {
1918  hasPartialLazyBinding = true;
1919  break;
1920  }
1921 
1922  return *D;
1923  }
1924 
1925  if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) {
1926  NonLoc index = ER->getIndex();
1927  if (!index.isConstant())
1928  hasSymbolicIndex = true;
1929  }
1930 
1931  // If our super region is a field or element itself, walk up the region
1932  // hierarchy to see if there is a default value installed in an ancestor.
1933  SR = dyn_cast<SubRegion>(Base);
1934  }
1935 
1936  if (R->hasStackNonParametersStorage()) {
1937  if (isa<ElementRegion>(R)) {
1938  // Currently we don't reason specially about Clang-style vectors. Check
1939  // if superR is a vector and if so return Unknown.
1940  if (const TypedValueRegion *typedSuperR =
1941  dyn_cast<TypedValueRegion>(R->getSuperRegion())) {
1942  if (typedSuperR->getValueType()->isVectorType())
1943  return UnknownVal();
1944  }
1945  }
1946 
1947  // FIXME: We also need to take ElementRegions with symbolic indexes into
1948  // account. This case handles both directly accessing an ElementRegion
1949  // with a symbolic offset, but also fields within an element with
1950  // a symbolic offset.
1951  if (hasSymbolicIndex)
1952  return UnknownVal();
1953 
1954  if (!hasPartialLazyBinding)
1955  return UndefinedVal();
1956  }
1957 
1958  // All other values are symbolic.
1959  return svalBuilder.getRegionValueSymbolVal(R);
1960 }
1961 
1962 SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B,
1963  const ObjCIvarRegion* R) {
1964  // Check if the region has a binding.
1965  if (const Optional<SVal> &V = B.getDirectBinding(R))
1966  return *V;
1967 
1968  const MemRegion *superR = R->getSuperRegion();
1969 
1970  // Check if the super region has a default binding.
1971  if (const Optional<SVal> &V = B.getDefaultBinding(superR)) {
1972  if (SymbolRef parentSym = V->getAsSymbol())
1973  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1974 
1975  // Other cases: give up.
1976  return UnknownVal();
1977  }
1978 
1979  return getBindingForLazySymbol(R);
1980 }
1981 
1982 SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B,
1983  const VarRegion *R) {
1984 
1985  // Check if the region has a binding.
1986  if (Optional<SVal> V = B.getDirectBinding(R))
1987  return *V;
1988 
1989  if (Optional<SVal> V = B.getDefaultBinding(R))
1990  return *V;
1991 
1992  // Lazily derive a value for the VarRegion.
1993  const VarDecl *VD = R->getDecl();
1994  const MemSpaceRegion *MS = R->getMemorySpace();
1995 
1996  // Arguments are always symbolic.
1997  if (isa<StackArgumentsSpaceRegion>(MS))
1998  return svalBuilder.getRegionValueSymbolVal(R);
1999 
2000  // Is 'VD' declared constant? If so, retrieve the constant value.
2001  if (VD->getType().isConstQualified()) {
2002  if (const Expr *Init = VD->getAnyInitializer()) {
2003  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
2004  return *V;
2005 
2006  // If the variable is const qualified and has an initializer but
2007  // we couldn't evaluate initializer to a value, treat the value as
2008  // unknown.
2009  return UnknownVal();
2010  }
2011  }
2012 
2013  // This must come after the check for constants because closure-captured
2014  // constant variables may appear in UnknownSpaceRegion.
2015  if (isa<UnknownSpaceRegion>(MS))
2016  return svalBuilder.getRegionValueSymbolVal(R);
2017 
2018  if (isa<GlobalsSpaceRegion>(MS)) {
2019  QualType T = VD->getType();
2020 
2021  // If we're in main(), then global initializers have not become stale yet.
2022  if (B.isMainAnalysis())
2023  if (const Expr *Init = VD->getAnyInitializer())
2024  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
2025  return *V;
2026 
2027  // Function-scoped static variables are default-initialized to 0; if they
2028  // have an initializer, it would have been processed by now.
2029  // FIXME: This is only true when we're starting analysis from main().
2030  // We're losing a lot of coverage here.
2031  if (isa<StaticGlobalSpaceRegion>(MS))
2032  return svalBuilder.makeZeroVal(T);
2033 
2034  if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) {
2035  assert(!V->getAs<nonloc::LazyCompoundVal>());
2036  return V.getValue();
2037  }
2038 
2039  return svalBuilder.getRegionValueSymbolVal(R);
2040  }
2041 
2042  return UndefinedVal();
2043 }
2044 
2045 SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
2046  // All other values are symbolic.
2047  return svalBuilder.getRegionValueSymbolVal(R);
2048 }
2049 
2050 const RegionStoreManager::SValListTy &
2051 RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) {
2052  // First, check the cache.
2053  LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData());
2054  if (I != LazyBindingsMap.end())
2055  return I->second;
2056 
2057  // If we don't have a list of values cached, start constructing it.
2058  SValListTy List;
2059 
2060  const SubRegion *LazyR = LCV.getRegion();
2061  RegionBindingsRef B = getRegionBindings(LCV.getStore());
2062 
2063  // If this region had /no/ bindings at the time, there are no interesting
2064  // values to return.
2065  const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion());
2066  if (!Cluster)
2067  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2068 
2070  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR,
2071  /*IncludeAllDefaultBindings=*/true);
2072  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
2073  E = Bindings.end();
2074  I != E; ++I) {
2075  SVal V = I->second;
2076  if (V.isUnknownOrUndef() || V.isConstant())
2077  continue;
2078 
2079  if (Optional<nonloc::LazyCompoundVal> InnerLCV =
2080  V.getAs<nonloc::LazyCompoundVal>()) {
2081  const SValListTy &InnerList = getInterestingValues(*InnerLCV);
2082  List.insert(List.end(), InnerList.begin(), InnerList.end());
2083  continue;
2084  }
2085 
2086  List.push_back(V);
2087  }
2088 
2089  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2090 }
2091 
2092 NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B,
2093  const TypedValueRegion *R) {
2095  getExistingLazyBinding(svalBuilder, B, R, false))
2096  return *V;
2097 
2098  return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R);
2099 }
2100 
2101 static bool isRecordEmpty(const RecordDecl *RD) {
2102  if (!RD->field_empty())
2103  return false;
2104  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD))
2105  return CRD->getNumBases() == 0;
2106  return true;
2107 }
2108 
2109 SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B,
2110  const TypedValueRegion *R) {
2111  const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl();
2112  if (!RD->getDefinition() || isRecordEmpty(RD))
2113  return UnknownVal();
2114 
2115  return createLazyBinding(B, R);
2116 }
2117 
2118 SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B,
2119  const TypedValueRegion *R) {
2120  assert(Ctx.getAsConstantArrayType(R->getValueType()) &&
2121  "Only constant array types can have compound bindings.");
2122 
2123  return createLazyBinding(B, R);
2124 }
2125 
2126 bool RegionStoreManager::includedInBindings(Store store,
2127  const MemRegion *region) const {
2128  RegionBindingsRef B = getRegionBindings(store);
2129  region = region->getBaseRegion();
2130 
2131  // Quick path: if the base is the head of a cluster, the region is live.
2132  if (B.lookup(region))
2133  return true;
2134 
2135  // Slow path: if the region is the VALUE of any binding, it is live.
2136  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) {
2137  const ClusterBindings &Cluster = RI.getData();
2138  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2139  CI != CE; ++CI) {
2140  const SVal &D = CI.getData();
2141  if (const MemRegion *R = D.getAsRegion())
2142  if (R->getBaseRegion() == region)
2143  return true;
2144  }
2145  }
2146 
2147  return false;
2148 }
2149 
2150 //===----------------------------------------------------------------------===//
2151 // Binding values to regions.
2152 //===----------------------------------------------------------------------===//
2153 
2154 StoreRef RegionStoreManager::killBinding(Store ST, Loc L) {
2155  if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>())
2156  if (const MemRegion* R = LV->getRegion())
2157  return StoreRef(getRegionBindings(ST).removeBinding(R)
2158  .asImmutableMap()
2159  .getRootWithoutRetain(),
2160  *this);
2161 
2162  return StoreRef(ST, *this);
2163 }
2164 
2165 RegionBindingsRef
2166 RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) {
2167  if (L.getAs<loc::ConcreteInt>())
2168  return B;
2169 
2170  // If we get here, the location should be a region.
2171  const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion();
2172 
2173  // Check if the region is a struct region.
2174  if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) {
2175  QualType Ty = TR->getValueType();
2176  if (Ty->isArrayType())
2177  return bindArray(B, TR, V);
2178  if (Ty->isStructureOrClassType())
2179  return bindStruct(B, TR, V);
2180  if (Ty->isVectorType())
2181  return bindVector(B, TR, V);
2182  if (Ty->isUnionType())
2183  return bindAggregate(B, TR, V);
2184  }
2185 
2186  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
2187  // Binding directly to a symbolic region should be treated as binding
2188  // to element 0.
2189  QualType T = SR->getSymbol()->getType();
2190  if (T->isAnyPointerType() || T->isReferenceType())
2191  T = T->getPointeeType();
2192 
2193  R = GetElementZeroRegion(SR, T);
2194  }
2195 
2196  assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) &&
2197  "'this' pointer is not an l-value and is not assignable");
2198 
2199  // Clear out bindings that may overlap with this binding.
2200  RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R));
2201  return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V);
2202 }
2203 
2204 RegionBindingsRef
2205 RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B,
2206  const MemRegion *R,
2207  QualType T) {
2208  SVal V;
2209 
2210  if (Loc::isLocType(T))
2211  V = svalBuilder.makeNull();
2212  else if (T->isIntegralOrEnumerationType())
2213  V = svalBuilder.makeZeroVal(T);
2214  else if (T->isStructureOrClassType() || T->isArrayType()) {
2215  // Set the default value to a zero constant when it is a structure
2216  // or array. The type doesn't really matter.
2217  V = svalBuilder.makeZeroVal(Ctx.IntTy);
2218  }
2219  else {
2220  // We can't represent values of this type, but we still need to set a value
2221  // to record that the region has been initialized.
2222  // If this assertion ever fires, a new case should be added above -- we
2223  // should know how to default-initialize any value we can symbolicate.
2224  assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
2225  V = UnknownVal();
2226  }
2227 
2228  return B.addBinding(R, BindingKey::Default, V);
2229 }
2230 
2231 RegionBindingsRef
2232 RegionStoreManager::bindArray(RegionBindingsConstRef B,
2233  const TypedValueRegion* R,
2234  SVal Init) {
2235 
2236  const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType()));
2237  QualType ElementTy = AT->getElementType();
2238  Optional<uint64_t> Size;
2239 
2240  if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT))
2241  Size = CAT->getSize().getZExtValue();
2242 
2243  // Check if the init expr is a literal. If so, bind the rvalue instead.
2244  // FIXME: It's not responsibility of the Store to transform this lvalue
2245  // to rvalue. ExprEngine or maybe even CFG should do this before binding.
2246  if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) {
2247  SVal V = getBinding(B.asStore(), *MRV, R->getValueType());
2248  return bindAggregate(B, R, V);
2249  }
2250 
2251  // Handle lazy compound values.
2252  if (Init.getAs<nonloc::LazyCompoundVal>())
2253  return bindAggregate(B, R, Init);
2254 
2255  if (Init.isUnknown())
2256  return bindAggregate(B, R, UnknownVal());
2257 
2258  // Remaining case: explicit compound values.
2259  const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>();
2260  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2261  uint64_t i = 0;
2262 
2263  RegionBindingsRef NewB(B);
2264 
2265  for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) {
2266  // The init list might be shorter than the array length.
2267  if (VI == VE)
2268  break;
2269 
2270  const NonLoc &Idx = svalBuilder.makeArrayIndex(i);
2271  const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx);
2272 
2273  if (ElementTy->isStructureOrClassType())
2274  NewB = bindStruct(NewB, ER, *VI);
2275  else if (ElementTy->isArrayType())
2276  NewB = bindArray(NewB, ER, *VI);
2277  else
2278  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2279  }
2280 
2281  // If the init list is shorter than the array length (or the array has
2282  // variable length), set the array default value. Values that are already set
2283  // are not overwritten.
2284  if (!Size.hasValue() || i < Size.getValue())
2285  NewB = setImplicitDefaultValue(NewB, R, ElementTy);
2286 
2287  return NewB;
2288 }
2289 
2290 RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B,
2291  const TypedValueRegion* R,
2292  SVal V) {
2293  QualType T = R->getValueType();
2294  const VectorType *VT = T->castAs<VectorType>(); // Use castAs for typedefs.
2295 
2296  // Handle lazy compound values and symbolic values.
2297  if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>())
2298  return bindAggregate(B, R, V);
2299 
2300  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2301  // that we are binding symbolic struct value. Kill the field values, and if
2302  // the value is symbolic go and bind it as a "default" binding.
2303  if (!V.getAs<nonloc::CompoundVal>()) {
2304  return bindAggregate(B, R, UnknownVal());
2305  }
2306 
2307  QualType ElemType = VT->getElementType();
2308  nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>();
2309  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2310  unsigned index = 0, numElements = VT->getNumElements();
2311  RegionBindingsRef NewB(B);
2312 
2313  for ( ; index != numElements ; ++index) {
2314  if (VI == VE)
2315  break;
2316 
2317  NonLoc Idx = svalBuilder.makeArrayIndex(index);
2318  const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx);
2319 
2320  if (ElemType->isArrayType())
2321  NewB = bindArray(NewB, ER, *VI);
2322  else if (ElemType->isStructureOrClassType())
2323  NewB = bindStruct(NewB, ER, *VI);
2324  else
2325  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2326  }
2327  return NewB;
2328 }
2329 
2331 RegionStoreManager::tryBindSmallStruct(RegionBindingsConstRef B,
2332  const TypedValueRegion *R,
2333  const RecordDecl *RD,
2334  nonloc::LazyCompoundVal LCV) {
2335  FieldVector Fields;
2336 
2337  if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(RD))
2338  if (Class->getNumBases() != 0 || Class->getNumVBases() != 0)
2339  return None;
2340 
2341  for (const auto *FD : RD->fields()) {
2342  if (FD->isUnnamedBitfield())
2343  continue;
2344 
2345  // If there are too many fields, or if any of the fields are aggregates,
2346  // just use the LCV as a default binding.
2347  if (Fields.size() == SmallStructLimit)
2348  return None;
2349 
2350  QualType Ty = FD->getType();
2351  if (!(Ty->isScalarType() || Ty->isReferenceType()))
2352  return None;
2353 
2354  Fields.push_back(FD);
2355  }
2356 
2357  RegionBindingsRef NewB = B;
2358 
2359  for (FieldVector::iterator I = Fields.begin(), E = Fields.end(); I != E; ++I){
2360  const FieldRegion *SourceFR = MRMgr.getFieldRegion(*I, LCV.getRegion());
2361  SVal V = getBindingForField(getRegionBindings(LCV.getStore()), SourceFR);
2362 
2363  const FieldRegion *DestFR = MRMgr.getFieldRegion(*I, R);
2364  NewB = bind(NewB, loc::MemRegionVal(DestFR), V);
2365  }
2366 
2367  return NewB;
2368 }
2369 
2370 RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B,
2371  const TypedValueRegion* R,
2372  SVal V) {
2373  if (!Features.supportsFields())
2374  return B;
2375 
2376  QualType T = R->getValueType();
2377  assert(T->isStructureOrClassType());
2378 
2379  const RecordType* RT = T->castAs<RecordType>();
2380  const RecordDecl *RD = RT->getDecl();
2381 
2382  if (!RD->isCompleteDefinition())
2383  return B;
2384 
2385  // Handle lazy compound values and symbolic values.
2387  V.getAs<nonloc::LazyCompoundVal>()) {
2388  if (Optional<RegionBindingsRef> NewB = tryBindSmallStruct(B, R, RD, *LCV))
2389  return *NewB;
2390  return bindAggregate(B, R, V);
2391  }
2392  if (V.getAs<nonloc::SymbolVal>())
2393  return bindAggregate(B, R, V);
2394 
2395  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2396  // that we are binding symbolic struct value. Kill the field values, and if
2397  // the value is symbolic go and bind it as a "default" binding.
2398  if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>())
2399  return bindAggregate(B, R, UnknownVal());
2400 
2401  // The raw CompoundVal is essentially a symbolic InitListExpr: an (immutable)
2402  // list of other values. It appears pretty much only when there's an actual
2403  // initializer list expression in the program, and the analyzer tries to
2404  // unwrap it as soon as possible.
2405  // This code is where such unwrap happens: when the compound value is put into
2406  // the object that it was supposed to initialize (it's an *initializer* list,
2407  // after all), instead of binding the whole value to the whole object, we bind
2408  // sub-values to sub-objects. Sub-values may themselves be compound values,
2409  // and in this case the procedure becomes recursive.
2410  // FIXME: The annoying part about compound values is that they don't carry
2411  // any sort of information about which value corresponds to which sub-object.
2412  // It's simply a list of values in the middle of nowhere; we expect to match
2413  // them to sub-objects, essentially, "by index": first value binds to
2414  // the first field, second value binds to the second field, etc.
2415  // It would have been much safer to organize non-lazy compound values as
2416  // a mapping from fields/bases to values.
2417  const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>();
2418  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2419 
2420  RegionBindingsRef NewB(B);
2421 
2422  // In C++17 aggregates may have base classes, handle those as well.
2423  // They appear before fields in the initializer list / compound value.
2424  if (const auto *CRD = dyn_cast<CXXRecordDecl>(RD)) {
2425  // If the object was constructed with a constructor, its value is a
2426  // LazyCompoundVal. If it's a raw CompoundVal, it means that we're
2427  // performing aggregate initialization. The only exception from this
2428  // rule is sending an Objective-C++ message that returns a C++ object
2429  // to a nil receiver; in this case the semantics is to return a
2430  // zero-initialized object even if it's a C++ object that doesn't have
2431  // this sort of constructor; the CompoundVal is empty in this case.
2432  assert((CRD->isAggregate() || (Ctx.getLangOpts().ObjC && VI == VE)) &&
2433  "Non-aggregates are constructed with a constructor!");
2434 
2435  for (const auto &B : CRD->bases()) {
2436  // (Multiple inheritance is fine though.)
2437  assert(!B.isVirtual() && "Aggregates cannot have virtual base classes!");
2438 
2439  if (VI == VE)
2440  break;
2441 
2442  QualType BTy = B.getType();
2443  assert(BTy->isStructureOrClassType() && "Base classes must be classes!");
2444 
2445  const CXXRecordDecl *BRD = BTy->getAsCXXRecordDecl();
2446  assert(BRD && "Base classes must be C++ classes!");
2447 
2448  const CXXBaseObjectRegion *BR =
2449  MRMgr.getCXXBaseObjectRegion(BRD, R, /*IsVirtual=*/false);
2450 
2451  NewB = bindStruct(NewB, BR, *VI);
2452 
2453  ++VI;
2454  }
2455  }
2456 
2458 
2459  for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
2460 
2461  if (VI == VE)
2462  break;
2463 
2464  // Skip any unnamed bitfields to stay in sync with the initializers.
2465  if (FI->isUnnamedBitfield())
2466  continue;
2467 
2468  QualType FTy = FI->getType();
2469  const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R);
2470 
2471  if (FTy->isArrayType())
2472  NewB = bindArray(NewB, FR, *VI);
2473  else if (FTy->isStructureOrClassType())
2474  NewB = bindStruct(NewB, FR, *VI);
2475  else
2476  NewB = bind(NewB, loc::MemRegionVal(FR), *VI);
2477  ++VI;
2478  }
2479 
2480  // There may be fewer values in the initialize list than the fields of struct.
2481  if (FI != FE) {
2482  NewB = NewB.addBinding(R, BindingKey::Default,
2483  svalBuilder.makeIntVal(0, false));
2484  }
2485 
2486  return NewB;
2487 }
2488 
2489 RegionBindingsRef
2490 RegionStoreManager::bindAggregate(RegionBindingsConstRef B,
2491  const TypedRegion *R,
2492  SVal Val) {
2493  // Remove the old bindings, using 'R' as the root of all regions
2494  // we will invalidate. Then add the new binding.
2495  return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val);
2496 }
2497 
2498 //===----------------------------------------------------------------------===//
2499 // State pruning.
2500 //===----------------------------------------------------------------------===//
2501 
2502 namespace {
2503 class RemoveDeadBindingsWorker
2504  : public ClusterAnalysis<RemoveDeadBindingsWorker> {
2506  SymbolReaper &SymReaper;
2507  const StackFrameContext *CurrentLCtx;
2508 
2509 public:
2510  RemoveDeadBindingsWorker(RegionStoreManager &rm,
2511  ProgramStateManager &stateMgr,
2512  RegionBindingsRef b, SymbolReaper &symReaper,
2513  const StackFrameContext *LCtx)
2514  : ClusterAnalysis<RemoveDeadBindingsWorker>(rm, stateMgr, b),
2515  SymReaper(symReaper), CurrentLCtx(LCtx) {}
2516 
2517  // Called by ClusterAnalysis.
2518  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C);
2519  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
2520  using ClusterAnalysis<RemoveDeadBindingsWorker>::VisitCluster;
2521 
2522  using ClusterAnalysis::AddToWorkList;
2523 
2524  bool AddToWorkList(const MemRegion *R);
2525 
2526  bool UpdatePostponed();
2527  void VisitBinding(SVal V);
2528 };
2529 }
2530 
2531 bool RemoveDeadBindingsWorker::AddToWorkList(const MemRegion *R) {
2532  const MemRegion *BaseR = R->getBaseRegion();
2533  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
2534 }
2535 
2536 void RemoveDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
2537  const ClusterBindings &C) {
2538 
2539  if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) {
2540  if (SymReaper.isLive(VR))
2541  AddToWorkList(baseR, &C);
2542 
2543  return;
2544  }
2545 
2546  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) {
2547  if (SymReaper.isLive(SR->getSymbol()))
2548  AddToWorkList(SR, &C);
2549  else
2550  Postponed.push_back(SR);
2551 
2552  return;
2553  }
2554 
2555  if (isa<NonStaticGlobalSpaceRegion>(baseR)) {
2556  AddToWorkList(baseR, &C);
2557  return;
2558  }
2559 
2560  // CXXThisRegion in the current or parent location context is live.
2561  if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) {
2562  const auto *StackReg =
2563  cast<StackArgumentsSpaceRegion>(TR->getSuperRegion());
2564  const StackFrameContext *RegCtx = StackReg->getStackFrame();
2565  if (CurrentLCtx &&
2566  (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx)))
2567  AddToWorkList(TR, &C);
2568  }
2569 }
2570 
2571 void RemoveDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
2572  const ClusterBindings *C) {
2573  if (!C)
2574  return;
2575 
2576  // Mark the symbol for any SymbolicRegion with live bindings as live itself.
2577  // This means we should continue to track that symbol.
2578  if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR))
2579  SymReaper.markLive(SymR->getSymbol());
2580 
2581  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) {
2582  // Element index of a binding key is live.
2583  SymReaper.markElementIndicesLive(I.getKey().getRegion());
2584 
2585  VisitBinding(I.getData());
2586  }
2587 }
2588 
2589 void RemoveDeadBindingsWorker::VisitBinding(SVal V) {
2590  // Is it a LazyCompoundVal? All referenced regions are live as well.
2592  V.getAs<nonloc::LazyCompoundVal>()) {
2593 
2594  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
2595 
2596  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
2597  E = Vals.end();
2598  I != E; ++I)
2599  VisitBinding(*I);
2600 
2601  return;
2602  }
2603 
2604  // If V is a region, then add it to the worklist.
2605  if (const MemRegion *R = V.getAsRegion()) {
2606  AddToWorkList(R);
2607  SymReaper.markLive(R);
2608 
2609  // All regions captured by a block are also live.
2610  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) {
2611  BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(),
2612  E = BR->referenced_vars_end();
2613  for ( ; I != E; ++I)
2614  AddToWorkList(I.getCapturedRegion());
2615  }
2616  }
2617 
2618 
2619  // Update the set of live symbols.
2620  for (auto SI = V.symbol_begin(), SE = V.symbol_end(); SI!=SE; ++SI)
2621  SymReaper.markLive(*SI);
2622 }
2623 
2624 bool RemoveDeadBindingsWorker::UpdatePostponed() {
2625  // See if any postponed SymbolicRegions are actually live now, after
2626  // having done a scan.
2627  bool Changed = false;
2628 
2629  for (auto I = Postponed.begin(), E = Postponed.end(); I != E; ++I) {
2630  if (const SymbolicRegion *SR = *I) {
2631  if (SymReaper.isLive(SR->getSymbol())) {
2632  Changed |= AddToWorkList(SR);
2633  *I = nullptr;
2634  }
2635  }
2636  }
2637 
2638  return Changed;
2639 }
2640 
2641 StoreRef RegionStoreManager::removeDeadBindings(Store store,
2642  const StackFrameContext *LCtx,
2643  SymbolReaper& SymReaper) {
2644  RegionBindingsRef B = getRegionBindings(store);
2645  RemoveDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
2646  W.GenerateClusters();
2647 
2648  // Enqueue the region roots onto the worklist.
2649  for (SymbolReaper::region_iterator I = SymReaper.region_begin(),
2650  E = SymReaper.region_end(); I != E; ++I) {
2651  W.AddToWorkList(*I);
2652  }
2653 
2654  do W.RunWorkList(); while (W.UpdatePostponed());
2655 
2656  // We have now scanned the store, marking reachable regions and symbols
2657  // as live. We now remove all the regions that are dead from the store
2658  // as well as update DSymbols with the set symbols that are now dead.
2659  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
2660  const MemRegion *Base = I.getKey();
2661 
2662  // If the cluster has been visited, we know the region has been marked.
2663  // Otherwise, remove the dead entry.
2664  if (!W.isVisited(Base))
2665  B = B.remove(Base);
2666  }
2667 
2668  return StoreRef(B.asStore(), *this);
2669 }
2670 
2671 //===----------------------------------------------------------------------===//
2672 // Utility methods.
2673 //===----------------------------------------------------------------------===//
2674 
2675 void RegionStoreManager::printJson(raw_ostream &Out, Store S, const char *NL,
2676  unsigned int Space, bool IsDot) const {
2677  RegionBindingsRef Bindings = getRegionBindings(S);
2678 
2679  Indent(Out, Space, IsDot) << "\"store\": ";
2680 
2681  if (Bindings.isEmpty()) {
2682  Out << "null," << NL;
2683  return;
2684  }
2685 
2686  Out << "{ \"pointer\": \"" << Bindings.asStore() << "\", \"items\": [" << NL;
2687  Bindings.printJson(Out, NL, Space + 1, IsDot);
2688  Indent(Out, Space, IsDot) << "]}," << NL;
2689 }
A (possibly-)qualified type.
Definition: Type.h:643
bool isArrayType() const
Definition: Type.h:6447
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:51
Specialize PointerLikeTypeTraits to allow LazyGenerationalUpdatePtr to be placed into a PointerUnion...
Definition: Dominators.h:30
internal::Matcher< Stmt > StatementMatcher
Definition: ASTMatchers.h:138
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:557
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:3992
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:2860
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.
const Expr * getAnyInitializer() const
Get the initializer for this variable, no matter which declaration it is attached to...
Definition: Decl.h:1224
QualType getElementType() const
Definition: Type.h:2881
Represents a variable declaration or definition.
Definition: Decl.h:827
const void * Store
Store - This opaque type encapsulates an immutable mapping from locations to values.
Definition: StoreRef.h:27
bool field_empty() const
Definition: Decl.h:3885
const internal::VariadicDynCastAllOfMatcher< Decl, VarDecl > varDecl
Matches variable declarations.
std::unique_ptr< StoreManager > CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr)
Represents a struct/union/class.
Definition: Decl.h:3662
llvm::ImmutableMap< BindingKey, SVal > ClusterBindings
SmallVector< const FieldDecl *, 8 > FieldVector
const SymExpr * SymbolRef
Definition: SymExpr.h:110
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:160
llvm::ImmutableList< SVal >::iterator iterator
Definition: SVals.h:467
RecordDecl * getDefinition() const
Returns the RecordDecl that actually defines this struct/union/class.
Definition: Decl.h:3867
field_range fields() const
Definition: Decl.h:3877
Represents a member of a struct/union/class.
Definition: Decl.h:2643
static bool canSymbolicate(QualType T)
bool isReferenceType() const
Definition: Type.h:6403
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:6754
static bool isLocType(QualType T)
Definition: SVals.h:329
unsigned getLength() const
Definition: Expr.h:1798
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:209
bool isScalarType() const
Definition: Type.h:6739
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:542
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1692
static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields)
When applied to a MemSpaceRegion, indicates the entire memory space should be invalidated.
Definition: MemRegion.h:1470
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:108
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:1050
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6923
#define V(N, I)
Definition: ASTContext.h:2921
__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-base.h:62
uint32_t getCodeUnit(size_t i) const
Definition: Expr.h:1784
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:3206
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:527
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:708
llvm::ImmutableMapRef< BindingKey, SVal > ClusterBindingsRef
bool isConstQualified() const
Determine whether this type is const-qualified.
Definition: Type.h:6207
bool isVoidPointerType() const
Definition: Type.cpp:521
Maps string IDs to AST nodes matched by parts of a matcher.
Definition: ASTMatchers.h:103
bool isStructureOrClassType() const
Definition: Type.cpp:513
Kind
llvm::APSInt APSInt
QualType getElementType() const
Definition: Type.h:3241
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:2790
bool hasGlobalStorage() const
Returns true for all variables that do not have local storage.
Definition: Decl.h:1092
bool isAnyPointerType() const
Definition: Type.h:6395
bool operator<(DeclarationName LHS, DeclarationName RHS)
Ordering on two declaration names.
bool isVectorType() const
Definition: Type.h:6483
Tells that a region&#39;s contents is not changed.
Definition: MemRegion.h:1460
Dataflow Directional Tag Classes.
raw_ostream & operator<<(raw_ostream &Out, const CheckerBase &Checker)
Dump checker name to stream.
Definition: Checker.cpp:35
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:2048
const Decl * getDecl() const
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:4444
const StackFrameContext * getStackFrame() const
std::pair< BindingKey, SVal > BindingPair
Stores options for the analyzer from the command line.
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:14652
__PTRDIFF_TYPE__ ptrdiff_t
A signed integer type that is the result of subtracting two pointers.
Definition: opencl-c-base.h:48
static bool isUnionField(const FieldRegion *FR)
Represents a C++ struct/union/class.
Definition: DeclCXX.h:255
bool isVoidType() const
Definition: Type.h:6650
StringLiteral - This represents a string literal expression, e.g.
Definition: Expr.h:1686
Defines the clang::TargetInfo interface.
unsigned getNumElements() const
Definition: Type.h:3242
raw_ostream & Indent(raw_ostream &Out, const unsigned int Space, bool IsDot)
Definition: JsonSupport.h:20
const RegionBindingsRef & RegionBindingsConstRef
QualType getType() const
Definition: Decl.h:655
#define true
Definition: stdbool.h:16
Represents the canonical version of C arrays with a specified constant size.
Definition: Type.h:2906