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  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 LLVM_DUMP_METHOD void BindingKey::dump() const { llvm::errs() << *this; }
139 
140 //===----------------------------------------------------------------------===//
141 // Actual Store type.
142 //===----------------------------------------------------------------------===//
143 
144 typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings;
145 typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef;
146 typedef std::pair<BindingKey, SVal> BindingPair;
147 
148 typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings>
150 
151 namespace {
152 class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *,
153  ClusterBindings> {
154  ClusterBindings::Factory *CBFactory;
155 
156 public:
157  typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>
158  ParentTy;
159 
160  RegionBindingsRef(ClusterBindings::Factory &CBFactory,
161  const RegionBindings::TreeTy *T,
162  RegionBindings::TreeTy::Factory *F)
163  : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F),
164  CBFactory(&CBFactory) {}
165 
166  RegionBindingsRef(const ParentTy &P, ClusterBindings::Factory &CBFactory)
167  : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P),
168  CBFactory(&CBFactory) {}
169 
170  RegionBindingsRef add(key_type_ref K, data_type_ref D) const {
171  return RegionBindingsRef(static_cast<const ParentTy *>(this)->add(K, D),
172  *CBFactory);
173  }
174 
175  RegionBindingsRef remove(key_type_ref K) const {
176  return RegionBindingsRef(static_cast<const ParentTy *>(this)->remove(K),
177  *CBFactory);
178  }
179 
180  RegionBindingsRef addBinding(BindingKey K, SVal V) const;
181 
182  RegionBindingsRef addBinding(const MemRegion *R,
183  BindingKey::Kind k, SVal V) const;
184 
185  const SVal *lookup(BindingKey K) const;
186  const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const;
187  using llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>::lookup;
188 
189  RegionBindingsRef removeBinding(BindingKey K);
190 
191  RegionBindingsRef removeBinding(const MemRegion *R,
192  BindingKey::Kind k);
193 
194  RegionBindingsRef removeBinding(const MemRegion *R) {
195  return removeBinding(R, BindingKey::Direct).
196  removeBinding(R, BindingKey::Default);
197  }
198 
199  Optional<SVal> getDirectBinding(const MemRegion *R) const;
200 
201  /// getDefaultBinding - Returns an SVal* representing an optional default
202  /// binding associated with a region and its subregions.
203  Optional<SVal> getDefaultBinding(const MemRegion *R) const;
204 
205  /// Return the internal tree as a Store.
206  Store asStore() const {
207  return asImmutableMap().getRootWithoutRetain();
208  }
209 
210  void printJson(raw_ostream &Out, const char *NL = "\n",
211  unsigned int Space = 0, bool IsDot = false) const {
212  for (iterator I = begin(); I != end(); ++I) {
213  // TODO: We might need a .printJson for I.getKey() as well.
214  Indent(Out, Space, IsDot)
215  << "{ \"cluster\": \"" << I.getKey() << "\", \"pointer\": \""
216  << (const void *)I.getKey() << "\", \"items\": [" << NL;
217 
218  ++Space;
219  const ClusterBindings &CB = I.getData();
220  for (ClusterBindings::iterator CI = CB.begin(); CI != CB.end(); ++CI) {
221  Indent(Out, Space, IsDot) << "{ " << CI.getKey() << ", \"value\": ";
222  CI.getData().printJson(Out, /*AddQuotes=*/true);
223  Out << " }";
224  if (std::next(CI) != CB.end())
225  Out << ',';
226  Out << NL;
227  }
228 
229  --Space;
230  Indent(Out, Space, IsDot) << "]}";
231  if (std::next(I) != end())
232  Out << ',';
233  Out << NL;
234  }
235  }
236 
237  LLVM_DUMP_METHOD void dump() const { printJson(llvm::errs()); }
238 };
239 } // end anonymous namespace
240 
241 typedef const RegionBindingsRef& RegionBindingsConstRef;
242 
243 Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const {
244  return Optional<SVal>::create(lookup(R, BindingKey::Direct));
245 }
246 
247 Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const {
248  return Optional<SVal>::create(lookup(R, BindingKey::Default));
249 }
250 
251 RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const {
252  const MemRegion *Base = K.getBaseRegion();
253 
254  const ClusterBindings *ExistingCluster = lookup(Base);
255  ClusterBindings Cluster =
256  (ExistingCluster ? *ExistingCluster : CBFactory->getEmptyMap());
257 
258  ClusterBindings NewCluster = CBFactory->add(Cluster, K, V);
259  return add(Base, NewCluster);
260 }
261 
262 
263 RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R,
264  BindingKey::Kind k,
265  SVal V) const {
266  return addBinding(BindingKey::Make(R, k), V);
267 }
268 
269 const SVal *RegionBindingsRef::lookup(BindingKey K) const {
270  const ClusterBindings *Cluster = lookup(K.getBaseRegion());
271  if (!Cluster)
272  return nullptr;
273  return Cluster->lookup(K);
274 }
275 
276 const SVal *RegionBindingsRef::lookup(const MemRegion *R,
277  BindingKey::Kind k) const {
278  return lookup(BindingKey::Make(R, k));
279 }
280 
281 RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) {
282  const MemRegion *Base = K.getBaseRegion();
283  const ClusterBindings *Cluster = lookup(Base);
284  if (!Cluster)
285  return *this;
286 
287  ClusterBindings NewCluster = CBFactory->remove(*Cluster, K);
288  if (NewCluster.isEmpty())
289  return remove(Base);
290  return add(Base, NewCluster);
291 }
292 
293 RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R,
294  BindingKey::Kind k){
295  return removeBinding(BindingKey::Make(R, k));
296 }
297 
298 //===----------------------------------------------------------------------===//
299 // Fine-grained control of RegionStoreManager.
300 //===----------------------------------------------------------------------===//
301 
302 namespace {
303 struct minimal_features_tag {};
304 struct maximal_features_tag {};
305 
306 class RegionStoreFeatures {
307  bool SupportsFields;
308 public:
309  RegionStoreFeatures(minimal_features_tag) :
310  SupportsFields(false) {}
311 
312  RegionStoreFeatures(maximal_features_tag) :
313  SupportsFields(true) {}
314 
315  void enableFields(bool t) { SupportsFields = t; }
316 
317  bool supportsFields() const { return SupportsFields; }
318 };
319 }
320 
321 //===----------------------------------------------------------------------===//
322 // Main RegionStore logic.
323 //===----------------------------------------------------------------------===//
324 
325 namespace {
326 class InvalidateRegionsWorker;
327 
328 class RegionStoreManager : public StoreManager {
329 public:
330  const RegionStoreFeatures Features;
331 
332  RegionBindings::Factory RBFactory;
333  mutable ClusterBindings::Factory CBFactory;
334 
335  typedef std::vector<SVal> SValListTy;
336 private:
337  typedef llvm::DenseMap<const LazyCompoundValData *,
338  SValListTy> LazyBindingsMapTy;
339  LazyBindingsMapTy LazyBindingsMap;
340 
341  /// The largest number of fields a struct can have and still be
342  /// considered "small".
343  ///
344  /// This is currently used to decide whether or not it is worth "forcing" a
345  /// LazyCompoundVal on bind.
346  ///
347  /// This is controlled by 'region-store-small-struct-limit' option.
348  /// To disable all small-struct-dependent behavior, set the option to "0".
349  unsigned SmallStructLimit;
350 
351  /// A helper used to populate the work list with the given set of
352  /// regions.
353  void populateWorkList(InvalidateRegionsWorker &W,
354  ArrayRef<SVal> Values,
355  InvalidatedRegions *TopLevelRegions);
356 
357 public:
358  RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f)
359  : StoreManager(mgr), Features(f),
360  RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()),
361  SmallStructLimit(0) {
362  SubEngine &Eng = StateMgr.getOwningEngine();
363  AnalyzerOptions &Options = Eng.getAnalysisManager().options;
364  SmallStructLimit = Options.RegionStoreSmallStructLimit;
365  }
366 
367 
368  /// setImplicitDefaultValue - Set the default binding for the provided
369  /// MemRegion to the value implicitly defined for compound literals when
370  /// the value is not specified.
371  RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B,
372  const MemRegion *R, QualType T);
373 
374  /// ArrayToPointer - Emulates the "decay" of an array to a pointer
375  /// type. 'Array' represents the lvalue of the array being decayed
376  /// to a pointer, and the returned SVal represents the decayed
377  /// version of that lvalue (i.e., a pointer to the first element of
378  /// the array). This is called by ExprEngine when evaluating
379  /// casts from arrays to pointers.
380  SVal ArrayToPointer(Loc Array, QualType ElementTy) override;
381 
382  StoreRef getInitialStore(const LocationContext *InitLoc) override {
383  return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this);
384  }
385 
386  //===-------------------------------------------------------------------===//
387  // Binding values to regions.
388  //===-------------------------------------------------------------------===//
389  RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K,
390  const Expr *Ex,
391  unsigned Count,
392  const LocationContext *LCtx,
393  RegionBindingsRef B,
394  InvalidatedRegions *Invalidated);
395 
396  StoreRef invalidateRegions(Store store,
397  ArrayRef<SVal> Values,
398  const Expr *E, unsigned Count,
399  const LocationContext *LCtx,
400  const CallEvent *Call,
401  InvalidatedSymbols &IS,
402  RegionAndSymbolInvalidationTraits &ITraits,
403  InvalidatedRegions *Invalidated,
404  InvalidatedRegions *InvalidatedTopLevel) override;
405 
406  bool scanReachableSymbols(Store S, const MemRegion *R,
407  ScanReachableSymbols &Callbacks) override;
408 
409  RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B,
410  const SubRegion *R);
411 
412 public: // Part of public interface to class.
413 
414  StoreRef Bind(Store store, Loc LV, SVal V) override {
415  return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this);
416  }
417 
418  RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V);
419 
420  // BindDefaultInitial is only used to initialize a region with
421  // a default value.
422  StoreRef BindDefaultInitial(Store store, const MemRegion *R,
423  SVal V) override {
424  RegionBindingsRef B = getRegionBindings(store);
425  // Use other APIs when you have to wipe the region that was initialized
426  // earlier.
427  assert(!(B.getDefaultBinding(R) || B.getDirectBinding(R)) &&
428  "Double initialization!");
429  B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
430  return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
431  }
432 
433  // BindDefaultZero is used for zeroing constructors that may accidentally
434  // overwrite existing bindings.
435  StoreRef BindDefaultZero(Store store, const MemRegion *R) override {
436  // FIXME: The offsets of empty bases can be tricky because of
437  // of the so called "empty base class optimization".
438  // If a base class has been optimized out
439  // we should not try to create a binding, otherwise we should.
440  // Unfortunately, at the moment ASTRecordLayout doesn't expose
441  // the actual sizes of the empty bases
442  // and trying to infer them from offsets/alignments
443  // seems to be error-prone and non-trivial because of the trailing padding.
444  // As a temporary mitigation we don't create bindings for empty bases.
445  if (const auto *BR = dyn_cast<CXXBaseObjectRegion>(R))
446  if (BR->getDecl()->isEmpty())
447  return StoreRef(store, *this);
448 
449  RegionBindingsRef B = getRegionBindings(store);
450  SVal V = svalBuilder.makeZeroVal(Ctx.CharTy);
451  B = removeSubRegionBindings(B, cast<SubRegion>(R));
452  B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
453  return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
454  }
455 
456  /// Attempt to extract the fields of \p LCV and bind them to the struct region
457  /// \p R.
458  ///
459  /// This path is used when it seems advantageous to "force" loading the values
460  /// within a LazyCompoundVal to bind memberwise to the struct region, rather
461  /// than using a Default binding at the base of the entire region. This is a
462  /// heuristic attempting to avoid building long chains of LazyCompoundVals.
463  ///
464  /// \returns The updated store bindings, or \c None if binding non-lazily
465  /// would be too expensive.
466  Optional<RegionBindingsRef> tryBindSmallStruct(RegionBindingsConstRef B,
467  const TypedValueRegion *R,
468  const RecordDecl *RD,
469  nonloc::LazyCompoundVal LCV);
470 
471  /// BindStruct - Bind a compound value to a structure.
472  RegionBindingsRef bindStruct(RegionBindingsConstRef B,
473  const TypedValueRegion* R, SVal V);
474 
475  /// BindVector - Bind a compound value to a vector.
476  RegionBindingsRef bindVector(RegionBindingsConstRef B,
477  const TypedValueRegion* R, SVal V);
478 
479  RegionBindingsRef bindArray(RegionBindingsConstRef B,
480  const TypedValueRegion* R,
481  SVal V);
482 
483  /// Clears out all bindings in the given region and assigns a new value
484  /// as a Default binding.
485  RegionBindingsRef bindAggregate(RegionBindingsConstRef B,
486  const TypedRegion *R,
487  SVal DefaultVal);
488 
489  /// Create a new store with the specified binding removed.
490  /// \param ST the original store, that is the basis for the new store.
491  /// \param L the location whose binding should be removed.
492  StoreRef killBinding(Store ST, Loc L) override;
493 
494  void incrementReferenceCount(Store store) override {
495  getRegionBindings(store).manualRetain();
496  }
497 
498  /// If the StoreManager supports it, decrement the reference count of
499  /// the specified Store object. If the reference count hits 0, the memory
500  /// associated with the object is recycled.
501  void decrementReferenceCount(Store store) override {
502  getRegionBindings(store).manualRelease();
503  }
504 
505  bool includedInBindings(Store store, const MemRegion *region) const override;
506 
507  /// Return the value bound to specified location in a given state.
508  ///
509  /// The high level logic for this method is this:
510  /// getBinding (L)
511  /// if L has binding
512  /// return L's binding
513  /// else if L is in killset
514  /// return unknown
515  /// else
516  /// if L is on stack or heap
517  /// return undefined
518  /// else
519  /// return symbolic
520  SVal getBinding(Store S, Loc L, QualType T) override {
521  return getBinding(getRegionBindings(S), L, T);
522  }
523 
524  Optional<SVal> getDefaultBinding(Store S, const MemRegion *R) override {
525  RegionBindingsRef B = getRegionBindings(S);
526  // Default bindings are always applied over a base region so look up the
527  // base region's default binding, otherwise the lookup will fail when R
528  // is at an offset from R->getBaseRegion().
529  return B.getDefaultBinding(R->getBaseRegion());
530  }
531 
532  SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType());
533 
534  SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R);
535 
536  SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R);
537 
538  SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R);
539 
540  SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R);
541 
542  SVal getBindingForLazySymbol(const TypedValueRegion *R);
543 
544  SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
545  const TypedValueRegion *R,
546  QualType Ty);
547 
548  SVal getLazyBinding(const SubRegion *LazyBindingRegion,
549  RegionBindingsRef LazyBinding);
550 
551  /// Get bindings for the values in a struct and return a CompoundVal, used
552  /// when doing struct copy:
553  /// struct s x, y;
554  /// x = y;
555  /// y's value is retrieved by this method.
556  SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R);
557  SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R);
558  NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R);
559 
560  /// Used to lazily generate derived symbols for bindings that are defined
561  /// implicitly by default bindings in a super region.
562  ///
563  /// Note that callers may need to specially handle LazyCompoundVals, which
564  /// are returned as is in case the caller needs to treat them differently.
565  Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
566  const MemRegion *superR,
567  const TypedValueRegion *R,
568  QualType Ty);
569 
570  /// Get the state and region whose binding this region \p R corresponds to.
571  ///
572  /// If there is no lazy binding for \p R, the returned value will have a null
573  /// \c second. Note that a null pointer can represents a valid Store.
574  std::pair<Store, const SubRegion *>
575  findLazyBinding(RegionBindingsConstRef B, const SubRegion *R,
576  const SubRegion *originalRegion);
577 
578  /// Returns the cached set of interesting SVals contained within a lazy
579  /// binding.
580  ///
581  /// The precise value of "interesting" is determined for the purposes of
582  /// RegionStore's internal analysis. It must always contain all regions and
583  /// symbols, but may omit constants and other kinds of SVal.
584  const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV);
585 
586  //===------------------------------------------------------------------===//
587  // State pruning.
588  //===------------------------------------------------------------------===//
589 
590  /// removeDeadBindings - Scans the RegionStore of 'state' for dead values.
591  /// It returns a new Store with these values removed.
592  StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
593  SymbolReaper& SymReaper) override;
594 
595  //===------------------------------------------------------------------===//
596  // Region "extents".
597  //===------------------------------------------------------------------===//
598 
599  // FIXME: This method will soon be eliminated; see the note in Store.h.
600  DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state,
601  const MemRegion* R,
602  QualType EleTy) override;
603 
604  //===------------------------------------------------------------------===//
605  // Utility methods.
606  //===------------------------------------------------------------------===//
607 
608  RegionBindingsRef getRegionBindings(Store store) const {
609  return RegionBindingsRef(CBFactory,
610  static_cast<const RegionBindings::TreeTy*>(store),
611  RBFactory.getTreeFactory());
612  }
613 
614  void printJson(raw_ostream &Out, Store S, const char *NL = "\n",
615  unsigned int Space = 0, bool IsDot = false) const override;
616 
617  void iterBindings(Store store, BindingsHandler& f) override {
618  RegionBindingsRef B = getRegionBindings(store);
619  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
620  const ClusterBindings &Cluster = I.getData();
621  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
622  CI != CE; ++CI) {
623  const BindingKey &K = CI.getKey();
624  if (!K.isDirect())
625  continue;
626  if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) {
627  // FIXME: Possibly incorporate the offset?
628  if (!f.HandleBinding(*this, store, R, CI.getData()))
629  return;
630  }
631  }
632  }
633  }
634 };
635 
636 } // end anonymous namespace
637 
638 //===----------------------------------------------------------------------===//
639 // RegionStore creation.
640 //===----------------------------------------------------------------------===//
641 
642 std::unique_ptr<StoreManager>
644  RegionStoreFeatures F = maximal_features_tag();
645  return llvm::make_unique<RegionStoreManager>(StMgr, F);
646 }
647 
648 std::unique_ptr<StoreManager>
650  RegionStoreFeatures F = minimal_features_tag();
651  F.enableFields(true);
652  return llvm::make_unique<RegionStoreManager>(StMgr, F);
653 }
654 
655 
656 //===----------------------------------------------------------------------===//
657 // Region Cluster analysis.
658 //===----------------------------------------------------------------------===//
659 
660 namespace {
661 /// Used to determine which global regions are automatically included in the
662 /// initial worklist of a ClusterAnalysis.
664  /// Don't include any global regions.
665  GFK_None,
666  /// Only include system globals.
667  GFK_SystemOnly,
668  /// Include all global regions.
669  GFK_All
670 };
671 
672 template <typename DERIVED>
673 class ClusterAnalysis {
674 protected:
675  typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap;
676  typedef const MemRegion * WorkListElement;
677  typedef SmallVector<WorkListElement, 10> WorkList;
678 
679  llvm::SmallPtrSet<const ClusterBindings *, 16> Visited;
680 
681  WorkList WL;
682 
683  RegionStoreManager &RM;
684  ASTContext &Ctx;
685  SValBuilder &svalBuilder;
686 
687  RegionBindingsRef B;
688 
689 
690 protected:
691  const ClusterBindings *getCluster(const MemRegion *R) {
692  return B.lookup(R);
693  }
694 
695  /// Returns true if all clusters in the given memspace should be initially
696  /// included in the cluster analysis. Subclasses may provide their
697  /// own implementation.
698  bool includeEntireMemorySpace(const MemRegion *Base) {
699  return false;
700  }
701 
702 public:
703  ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr,
704  RegionBindingsRef b)
705  : RM(rm), Ctx(StateMgr.getContext()),
706  svalBuilder(StateMgr.getSValBuilder()), B(std::move(b)) {}
707 
708  RegionBindingsRef getRegionBindings() const { return B; }
709 
710  bool isVisited(const MemRegion *R) {
711  return Visited.count(getCluster(R));
712  }
713 
714  void GenerateClusters() {
715  // Scan the entire set of bindings and record the region clusters.
716  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end();
717  RI != RE; ++RI){
718  const MemRegion *Base = RI.getKey();
719 
720  const ClusterBindings &Cluster = RI.getData();
721  assert(!Cluster.isEmpty() && "Empty clusters should be removed");
722  static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster);
723 
724  // If the base's memspace should be entirely invalidated, add the cluster
725  // to the workspace up front.
726  if (static_cast<DERIVED*>(this)->includeEntireMemorySpace(Base))
727  AddToWorkList(WorkListElement(Base), &Cluster);
728  }
729  }
730 
731  bool AddToWorkList(WorkListElement E, const ClusterBindings *C) {
732  if (C && !Visited.insert(C).second)
733  return false;
734  WL.push_back(E);
735  return true;
736  }
737 
738  bool AddToWorkList(const MemRegion *R) {
739  return static_cast<DERIVED*>(this)->AddToWorkList(R);
740  }
741 
742  void RunWorkList() {
743  while (!WL.empty()) {
744  WorkListElement E = WL.pop_back_val();
745  const MemRegion *BaseR = E;
746 
747  static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR));
748  }
749  }
750 
751  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {}
752  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {}
753 
754  void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C,
755  bool Flag) {
756  static_cast<DERIVED*>(this)->VisitCluster(BaseR, C);
757  }
758 };
759 }
760 
761 //===----------------------------------------------------------------------===//
762 // Binding invalidation.
763 //===----------------------------------------------------------------------===//
764 
765 bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R,
766  ScanReachableSymbols &Callbacks) {
767  assert(R == R->getBaseRegion() && "Should only be called for base regions");
768  RegionBindingsRef B = getRegionBindings(S);
769  const ClusterBindings *Cluster = B.lookup(R);
770 
771  if (!Cluster)
772  return true;
773 
774  for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end();
775  RI != RE; ++RI) {
776  if (!Callbacks.scan(RI.getData()))
777  return false;
778  }
779 
780  return true;
781 }
782 
783 static inline bool isUnionField(const FieldRegion *FR) {
784  return FR->getDecl()->getParent()->isUnion();
785 }
786 
788 
789 static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) {
790  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
791 
792  const MemRegion *Base = K.getConcreteOffsetRegion();
793  const MemRegion *R = K.getRegion();
794 
795  while (R != Base) {
796  if (const FieldRegion *FR = dyn_cast<FieldRegion>(R))
797  if (!isUnionField(FR))
798  Fields.push_back(FR->getDecl());
799 
800  R = cast<SubRegion>(R)->getSuperRegion();
801  }
802 }
803 
804 static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) {
805  assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
806 
807  if (Fields.empty())
808  return true;
809 
810  FieldVector FieldsInBindingKey;
811  getSymbolicOffsetFields(K, FieldsInBindingKey);
812 
813  ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size();
814  if (Delta >= 0)
815  return std::equal(FieldsInBindingKey.begin() + Delta,
816  FieldsInBindingKey.end(),
817  Fields.begin());
818  else
819  return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(),
820  Fields.begin() - Delta);
821 }
822 
823 /// Collects all bindings in \p Cluster that may refer to bindings within
824 /// \p Top.
825 ///
826 /// Each binding is a pair whose \c first is the key (a BindingKey) and whose
827 /// \c second is the value (an SVal).
828 ///
829 /// The \p IncludeAllDefaultBindings parameter specifies whether to include
830 /// default bindings that may extend beyond \p Top itself, e.g. if \p Top is
831 /// an aggregate within a larger aggregate with a default binding.
832 static void
834  SValBuilder &SVB, const ClusterBindings &Cluster,
835  const SubRegion *Top, BindingKey TopKey,
836  bool IncludeAllDefaultBindings) {
837  FieldVector FieldsInSymbolicSubregions;
838  if (TopKey.hasSymbolicOffset()) {
839  getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions);
840  Top = TopKey.getConcreteOffsetRegion();
841  TopKey = BindingKey::Make(Top, BindingKey::Default);
842  }
843 
844  // Find the length (in bits) of the region being invalidated.
845  uint64_t Length = UINT64_MAX;
846  SVal Extent = Top->getExtent(SVB);
847  if (Optional<nonloc::ConcreteInt> ExtentCI =
848  Extent.getAs<nonloc::ConcreteInt>()) {
849  const llvm::APSInt &ExtentInt = ExtentCI->getValue();
850  assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned());
851  // Extents are in bytes but region offsets are in bits. Be careful!
852  Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth();
853  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) {
854  if (FR->getDecl()->isBitField())
855  Length = FR->getDecl()->getBitWidthValue(SVB.getContext());
856  }
857 
858  for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end();
859  I != E; ++I) {
860  BindingKey NextKey = I.getKey();
861  if (NextKey.getRegion() == TopKey.getRegion()) {
862  // FIXME: This doesn't catch the case where we're really invalidating a
863  // region with a symbolic offset. Example:
864  // R: points[i].y
865  // Next: points[0].x
866 
867  if (NextKey.getOffset() > TopKey.getOffset() &&
868  NextKey.getOffset() - TopKey.getOffset() < Length) {
869  // Case 1: The next binding is inside the region we're invalidating.
870  // Include it.
871  Bindings.push_back(*I);
872 
873  } else if (NextKey.getOffset() == TopKey.getOffset()) {
874  // Case 2: The next binding is at the same offset as the region we're
875  // invalidating. In this case, we need to leave default bindings alone,
876  // since they may be providing a default value for a regions beyond what
877  // we're invalidating.
878  // FIXME: This is probably incorrect; consider invalidating an outer
879  // struct whose first field is bound to a LazyCompoundVal.
880  if (IncludeAllDefaultBindings || NextKey.isDirect())
881  Bindings.push_back(*I);
882  }
883 
884  } else if (NextKey.hasSymbolicOffset()) {
885  const MemRegion *Base = NextKey.getConcreteOffsetRegion();
886  if (Top->isSubRegionOf(Base) && Top != Base) {
887  // Case 3: The next key is symbolic and we just changed something within
888  // its concrete region. We don't know if the binding is still valid, so
889  // we'll be conservative and include it.
890  if (IncludeAllDefaultBindings || NextKey.isDirect())
891  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
892  Bindings.push_back(*I);
893  } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) {
894  // Case 4: The next key is symbolic, but we changed a known
895  // super-region. In this case the binding is certainly included.
896  if (BaseSR->isSubRegionOf(Top))
897  if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
898  Bindings.push_back(*I);
899  }
900  }
901  }
902 }
903 
904 static void
906  SValBuilder &SVB, const ClusterBindings &Cluster,
907  const SubRegion *Top, bool IncludeAllDefaultBindings) {
908  collectSubRegionBindings(Bindings, SVB, Cluster, Top,
910  IncludeAllDefaultBindings);
911 }
912 
913 RegionBindingsRef
914 RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B,
915  const SubRegion *Top) {
916  BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default);
917  const MemRegion *ClusterHead = TopKey.getBaseRegion();
918 
919  if (Top == ClusterHead) {
920  // We can remove an entire cluster's bindings all in one go.
921  return B.remove(Top);
922  }
923 
924  const ClusterBindings *Cluster = B.lookup(ClusterHead);
925  if (!Cluster) {
926  // If we're invalidating a region with a symbolic offset, we need to make
927  // sure we don't treat the base region as uninitialized anymore.
928  if (TopKey.hasSymbolicOffset()) {
929  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
930  return B.addBinding(Concrete, BindingKey::Default, UnknownVal());
931  }
932  return B;
933  }
934 
936  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey,
937  /*IncludeAllDefaultBindings=*/false);
938 
939  ClusterBindingsRef Result(*Cluster, CBFactory);
940  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
941  E = Bindings.end();
942  I != E; ++I)
943  Result = Result.remove(I->first);
944 
945  // If we're invalidating a region with a symbolic offset, we need to make sure
946  // we don't treat the base region as uninitialized anymore.
947  // FIXME: This isn't very precise; see the example in
948  // collectSubRegionBindings.
949  if (TopKey.hasSymbolicOffset()) {
950  const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
951  Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default),
952  UnknownVal());
953  }
954 
955  if (Result.isEmpty())
956  return B.remove(ClusterHead);
957  return B.add(ClusterHead, Result.asImmutableMap());
958 }
959 
960 namespace {
961 class InvalidateRegionsWorker : public ClusterAnalysis<InvalidateRegionsWorker>
962 {
963  const Expr *Ex;
964  unsigned Count;
965  const LocationContext *LCtx;
966  InvalidatedSymbols &IS;
967  RegionAndSymbolInvalidationTraits &ITraits;
969  GlobalsFilterKind GlobalsFilter;
970 public:
971  InvalidateRegionsWorker(RegionStoreManager &rm,
972  ProgramStateManager &stateMgr,
973  RegionBindingsRef b,
974  const Expr *ex, unsigned count,
975  const LocationContext *lctx,
976  InvalidatedSymbols &is,
977  RegionAndSymbolInvalidationTraits &ITraitsIn,
979  GlobalsFilterKind GFK)
980  : ClusterAnalysis<InvalidateRegionsWorker>(rm, stateMgr, b),
981  Ex(ex), Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r),
982  GlobalsFilter(GFK) {}
983 
984  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
985  void VisitBinding(SVal V);
986 
987  using ClusterAnalysis::AddToWorkList;
988 
989  bool AddToWorkList(const MemRegion *R);
990 
991  /// Returns true if all clusters in the memory space for \p Base should be
992  /// be invalidated.
993  bool includeEntireMemorySpace(const MemRegion *Base);
994 
995  /// Returns true if the memory space of the given region is one of the global
996  /// regions specially included at the start of invalidation.
997  bool isInitiallyIncludedGlobalRegion(const MemRegion *R);
998 };
999 }
1000 
1001 bool InvalidateRegionsWorker::AddToWorkList(const MemRegion *R) {
1002  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1004  const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion();
1005  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
1006 }
1007 
1008 void InvalidateRegionsWorker::VisitBinding(SVal V) {
1009  // A symbol? Mark it touched by the invalidation.
1010  if (SymbolRef Sym = V.getAsSymbol())
1011  IS.insert(Sym);
1012 
1013  if (const MemRegion *R = V.getAsRegion()) {
1014  AddToWorkList(R);
1015  return;
1016  }
1017 
1018  // Is it a LazyCompoundVal? All references get invalidated as well.
1020  V.getAs<nonloc::LazyCompoundVal>()) {
1021 
1022  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
1023 
1024  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
1025  E = Vals.end();
1026  I != E; ++I)
1027  VisitBinding(*I);
1028 
1029  return;
1030  }
1031 }
1032 
1033 void InvalidateRegionsWorker::VisitCluster(const MemRegion *baseR,
1034  const ClusterBindings *C) {
1035 
1036  bool PreserveRegionsContents =
1037  ITraits.hasTrait(baseR,
1039 
1040  if (C) {
1041  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I)
1042  VisitBinding(I.getData());
1043 
1044  // Invalidate regions contents.
1045  if (!PreserveRegionsContents)
1046  B = B.remove(baseR);
1047  }
1048 
1049  if (const auto *TO = dyn_cast<TypedValueRegion>(baseR)) {
1050  if (const auto *RD = TO->getValueType()->getAsCXXRecordDecl()) {
1051 
1052  // Lambdas can affect all static local variables without explicitly
1053  // capturing those.
1054  // We invalidate all static locals referenced inside the lambda body.
1055  if (RD->isLambda() && RD->getLambdaCallOperator()->getBody()) {
1056  using namespace ast_matchers;
1057 
1058  const char *DeclBind = "DeclBind";
1060  to(varDecl(hasStaticStorageDuration()).bind(DeclBind)))));
1061  auto Matches =
1062  match(RefToStatic, *RD->getLambdaCallOperator()->getBody(),
1063  RD->getASTContext());
1064 
1065  for (BoundNodes &Match : Matches) {
1066  auto *VD = Match.getNodeAs<VarDecl>(DeclBind);
1067  const VarRegion *ToInvalidate =
1068  RM.getRegionManager().getVarRegion(VD, LCtx);
1069  AddToWorkList(ToInvalidate);
1070  }
1071  }
1072  }
1073  }
1074 
1075  // BlockDataRegion? If so, invalidate captured variables that are passed
1076  // by reference.
1077  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) {
1078  for (BlockDataRegion::referenced_vars_iterator
1079  BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ;
1080  BI != BE; ++BI) {
1081  const VarRegion *VR = BI.getCapturedRegion();
1082  const VarDecl *VD = VR->getDecl();
1083  if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage()) {
1084  AddToWorkList(VR);
1085  }
1086  else if (Loc::isLocType(VR->getValueType())) {
1087  // Map the current bindings to a Store to retrieve the value
1088  // of the binding. If that binding itself is a region, we should
1089  // invalidate that region. This is because a block may capture
1090  // a pointer value, but the thing pointed by that pointer may
1091  // get invalidated.
1092  SVal V = RM.getBinding(B, loc::MemRegionVal(VR));
1093  if (Optional<Loc> L = V.getAs<Loc>()) {
1094  if (const MemRegion *LR = L->getAsRegion())
1095  AddToWorkList(LR);
1096  }
1097  }
1098  }
1099  return;
1100  }
1101 
1102  // Symbolic region?
1103  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR))
1104  IS.insert(SR->getSymbol());
1105 
1106  // Nothing else should be done in the case when we preserve regions context.
1107  if (PreserveRegionsContents)
1108  return;
1109 
1110  // Otherwise, we have a normal data region. Record that we touched the region.
1111  if (Regions)
1112  Regions->push_back(baseR);
1113 
1114  if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) {
1115  // Invalidate the region by setting its default value to
1116  // conjured symbol. The type of the symbol is irrelevant.
1117  DefinedOrUnknownSVal V =
1118  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
1119  B = B.addBinding(baseR, BindingKey::Default, V);
1120  return;
1121  }
1122 
1123  if (!baseR->isBoundable())
1124  return;
1125 
1126  const TypedValueRegion *TR = cast<TypedValueRegion>(baseR);
1127  QualType T = TR->getValueType();
1128 
1129  if (isInitiallyIncludedGlobalRegion(baseR)) {
1130  // If the region is a global and we are invalidating all globals,
1131  // erasing the entry is good enough. This causes all globals to be lazily
1132  // symbolicated from the same base symbol.
1133  return;
1134  }
1135 
1136  if (T->isRecordType()) {
1137  // Invalidate the region by setting its default value to
1138  // conjured symbol. The type of the symbol is irrelevant.
1139  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1140  Ctx.IntTy, Count);
1141  B = B.addBinding(baseR, BindingKey::Default, V);
1142  return;
1143  }
1144 
1145  if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
1146  bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1147  baseR,
1149 
1150  if (doNotInvalidateSuperRegion) {
1151  // We are not doing blank invalidation of the whole array region so we
1152  // have to manually invalidate each elements.
1153  Optional<uint64_t> NumElements;
1154 
1155  // Compute lower and upper offsets for region within array.
1156  if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT))
1157  NumElements = CAT->getSize().getZExtValue();
1158  if (!NumElements) // We are not dealing with a constant size array
1159  goto conjure_default;
1160  QualType ElementTy = AT->getElementType();
1161  uint64_t ElemSize = Ctx.getTypeSize(ElementTy);
1162  const RegionOffset &RO = baseR->getAsOffset();
1163  const MemRegion *SuperR = baseR->getBaseRegion();
1164  if (RO.hasSymbolicOffset()) {
1165  // If base region has a symbolic offset,
1166  // we revert to invalidating the super region.
1167  if (SuperR)
1168  AddToWorkList(SuperR);
1169  goto conjure_default;
1170  }
1171 
1172  uint64_t LowerOffset = RO.getOffset();
1173  uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize;
1174  bool UpperOverflow = UpperOffset < LowerOffset;
1175 
1176  // Invalidate regions which are within array boundaries,
1177  // or have a symbolic offset.
1178  if (!SuperR)
1179  goto conjure_default;
1180 
1181  const ClusterBindings *C = B.lookup(SuperR);
1182  if (!C)
1183  goto conjure_default;
1184 
1185  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E;
1186  ++I) {
1187  const BindingKey &BK = I.getKey();
1188  Optional<uint64_t> ROffset =
1189  BK.hasSymbolicOffset() ? Optional<uint64_t>() : BK.getOffset();
1190 
1191  // Check offset is not symbolic and within array's boundaries.
1192  // Handles arrays of 0 elements and of 0-sized elements as well.
1193  if (!ROffset ||
1194  ((*ROffset >= LowerOffset && *ROffset < UpperOffset) ||
1195  (UpperOverflow &&
1196  (*ROffset >= LowerOffset || *ROffset < UpperOffset)) ||
1197  (LowerOffset == UpperOffset && *ROffset == LowerOffset))) {
1198  B = B.removeBinding(I.getKey());
1199  // Bound symbolic regions need to be invalidated for dead symbol
1200  // detection.
1201  SVal V = I.getData();
1202  const MemRegion *R = V.getAsRegion();
1203  if (R && isa<SymbolicRegion>(R))
1204  VisitBinding(V);
1205  }
1206  }
1207  }
1208  conjure_default:
1209  // Set the default value of the array to conjured symbol.
1210  DefinedOrUnknownSVal V =
1211  svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1212  AT->getElementType(), Count);
1213  B = B.addBinding(baseR, BindingKey::Default, V);
1214  return;
1215  }
1216 
1217  DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1218  T,Count);
1219  assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
1220  B = B.addBinding(baseR, BindingKey::Direct, V);
1221 }
1222 
1223 bool InvalidateRegionsWorker::isInitiallyIncludedGlobalRegion(
1224  const MemRegion *R) {
1225  switch (GlobalsFilter) {
1226  case GFK_None:
1227  return false;
1228  case GFK_SystemOnly:
1229  return isa<GlobalSystemSpaceRegion>(R->getMemorySpace());
1230  case GFK_All:
1231  return isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace());
1232  }
1233 
1234  llvm_unreachable("unknown globals filter");
1235 }
1236 
1237 bool InvalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) {
1238  if (isInitiallyIncludedGlobalRegion(Base))
1239  return true;
1240 
1241  const MemSpaceRegion *MemSpace = Base->getMemorySpace();
1242  return ITraits.hasTrait(MemSpace,
1244 }
1245 
1246 RegionBindingsRef
1247 RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K,
1248  const Expr *Ex,
1249  unsigned Count,
1250  const LocationContext *LCtx,
1251  RegionBindingsRef B,
1252  InvalidatedRegions *Invalidated) {
1253  // Bind the globals memory space to a new symbol that we will use to derive
1254  // the bindings for all globals.
1255  const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K);
1256  SVal V = svalBuilder.conjureSymbolVal(/* symbolTag = */ (const void*) GS, Ex, LCtx,
1257  /* type does not matter */ Ctx.IntTy,
1258  Count);
1259 
1260  B = B.removeBinding(GS)
1261  .addBinding(BindingKey::Make(GS, BindingKey::Default), V);
1262 
1263  // Even if there are no bindings in the global scope, we still need to
1264  // record that we touched it.
1265  if (Invalidated)
1266  Invalidated->push_back(GS);
1267 
1268  return B;
1269 }
1270 
1271 void RegionStoreManager::populateWorkList(InvalidateRegionsWorker &W,
1272  ArrayRef<SVal> Values,
1273  InvalidatedRegions *TopLevelRegions) {
1274  for (ArrayRef<SVal>::iterator I = Values.begin(),
1275  E = Values.end(); I != E; ++I) {
1276  SVal V = *I;
1278  V.getAs<nonloc::LazyCompoundVal>()) {
1279 
1280  const SValListTy &Vals = getInterestingValues(*LCS);
1281 
1282  for (SValListTy::const_iterator I = Vals.begin(),
1283  E = Vals.end(); I != E; ++I) {
1284  // Note: the last argument is false here because these are
1285  // non-top-level regions.
1286  if (const MemRegion *R = (*I).getAsRegion())
1287  W.AddToWorkList(R);
1288  }
1289  continue;
1290  }
1291 
1292  if (const MemRegion *R = V.getAsRegion()) {
1293  if (TopLevelRegions)
1294  TopLevelRegions->push_back(R);
1295  W.AddToWorkList(R);
1296  continue;
1297  }
1298  }
1299 }
1300 
1301 StoreRef
1302 RegionStoreManager::invalidateRegions(Store store,
1303  ArrayRef<SVal> Values,
1304  const Expr *Ex, unsigned Count,
1305  const LocationContext *LCtx,
1306  const CallEvent *Call,
1307  InvalidatedSymbols &IS,
1308  RegionAndSymbolInvalidationTraits &ITraits,
1309  InvalidatedRegions *TopLevelRegions,
1310  InvalidatedRegions *Invalidated) {
1311  GlobalsFilterKind GlobalsFilter;
1312  if (Call) {
1313  if (Call->isInSystemHeader())
1314  GlobalsFilter = GFK_SystemOnly;
1315  else
1316  GlobalsFilter = GFK_All;
1317  } else {
1318  GlobalsFilter = GFK_None;
1319  }
1320 
1321  RegionBindingsRef B = getRegionBindings(store);
1322  InvalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, ITraits,
1323  Invalidated, GlobalsFilter);
1324 
1325  // Scan the bindings and generate the clusters.
1326  W.GenerateClusters();
1327 
1328  // Add the regions to the worklist.
1329  populateWorkList(W, Values, TopLevelRegions);
1330 
1331  W.RunWorkList();
1332 
1333  // Return the new bindings.
1334  B = W.getRegionBindings();
1335 
1336  // For calls, determine which global regions should be invalidated and
1337  // invalidate them. (Note that function-static and immutable globals are never
1338  // invalidated by this.)
1339  // TODO: This could possibly be more precise with modules.
1340  switch (GlobalsFilter) {
1341  case GFK_All:
1342  B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind,
1343  Ex, Count, LCtx, B, Invalidated);
1344  LLVM_FALLTHROUGH;
1345  case GFK_SystemOnly:
1346  B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
1347  Ex, Count, LCtx, B, Invalidated);
1348  LLVM_FALLTHROUGH;
1349  case GFK_None:
1350  break;
1351  }
1352 
1353  return StoreRef(B.asStore(), *this);
1354 }
1355 
1356 //===----------------------------------------------------------------------===//
1357 // Extents for regions.
1358 //===----------------------------------------------------------------------===//
1359 
1360 DefinedOrUnknownSVal
1361 RegionStoreManager::getSizeInElements(ProgramStateRef state,
1362  const MemRegion *R,
1363  QualType EleTy) {
1364  SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder);
1365  const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size);
1366  if (!SizeInt)
1367  return UnknownVal();
1368 
1369  CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue());
1370 
1371  if (Ctx.getAsVariableArrayType(EleTy)) {
1372  // FIXME: We need to track extra state to properly record the size
1373  // of VLAs. Returning UnknownVal here, however, is a stop-gap so that
1374  // we don't have a divide-by-zero below.
1375  return UnknownVal();
1376  }
1377 
1378  CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy);
1379 
1380  // If a variable is reinterpreted as a type that doesn't fit into a larger
1381  // type evenly, round it down.
1382  // This is a signed value, since it's used in arithmetic with signed indices.
1383  return svalBuilder.makeIntVal(RegionSize / EleSize,
1384  svalBuilder.getArrayIndexType());
1385 }
1386 
1387 //===----------------------------------------------------------------------===//
1388 // Location and region casting.
1389 //===----------------------------------------------------------------------===//
1390 
1391 /// ArrayToPointer - Emulates the "decay" of an array to a pointer
1392 /// type. 'Array' represents the lvalue of the array being decayed
1393 /// to a pointer, and the returned SVal represents the decayed
1394 /// version of that lvalue (i.e., a pointer to the first element of
1395 /// the array). This is called by ExprEngine when evaluating casts
1396 /// from arrays to pointers.
1397 SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) {
1398  if (Array.getAs<loc::ConcreteInt>())
1399  return Array;
1400 
1401  if (!Array.getAs<loc::MemRegionVal>())
1402  return UnknownVal();
1403 
1404  const SubRegion *R =
1405  cast<SubRegion>(Array.castAs<loc::MemRegionVal>().getRegion());
1406  NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
1407  return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, R, Ctx));
1408 }
1409 
1410 //===----------------------------------------------------------------------===//
1411 // Loading values from regions.
1412 //===----------------------------------------------------------------------===//
1413 
1414 SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) {
1415  assert(!L.getAs<UnknownVal>() && "location unknown");
1416  assert(!L.getAs<UndefinedVal>() && "location undefined");
1417 
1418  // For access to concrete addresses, return UnknownVal. Checks
1419  // for null dereferences (and similar errors) are done by checkers, not
1420  // the Store.
1421  // FIXME: We can consider lazily symbolicating such memory, but we really
1422  // should defer this when we can reason easily about symbolicating arrays
1423  // of bytes.
1424  if (L.getAs<loc::ConcreteInt>()) {
1425  return UnknownVal();
1426  }
1427  if (!L.getAs<loc::MemRegionVal>()) {
1428  return UnknownVal();
1429  }
1430 
1431  const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion();
1432 
1433  if (isa<BlockDataRegion>(MR)) {
1434  return UnknownVal();
1435  }
1436 
1437  if (!isa<TypedValueRegion>(MR)) {
1438  if (T.isNull()) {
1439  if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
1440  T = TR->getLocationType()->getPointeeType();
1441  else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1442  T = SR->getSymbol()->getType()->getPointeeType();
1443  }
1444  assert(!T.isNull() && "Unable to auto-detect binding type!");
1445  assert(!T->isVoidType() && "Attempting to dereference a void pointer!");
1446  MR = GetElementZeroRegion(cast<SubRegion>(MR), T);
1447  } else {
1448  T = cast<TypedValueRegion>(MR)->getValueType();
1449  }
1450 
1451  // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
1452  // instead of 'Loc', and have the other Loc cases handled at a higher level.
1453  const TypedValueRegion *R = cast<TypedValueRegion>(MR);
1454  QualType RTy = R->getValueType();
1455 
1456  // FIXME: we do not yet model the parts of a complex type, so treat the
1457  // whole thing as "unknown".
1458  if (RTy->isAnyComplexType())
1459  return UnknownVal();
1460 
1461  // FIXME: We should eventually handle funny addressing. e.g.:
1462  //
1463  // int x = ...;
1464  // int *p = &x;
1465  // char *q = (char*) p;
1466  // char c = *q; // returns the first byte of 'x'.
1467  //
1468  // Such funny addressing will occur due to layering of regions.
1469  if (RTy->isStructureOrClassType())
1470  return getBindingForStruct(B, R);
1471 
1472  // FIXME: Handle unions.
1473  if (RTy->isUnionType())
1474  return createLazyBinding(B, R);
1475 
1476  if (RTy->isArrayType()) {
1477  if (RTy->isConstantArrayType())
1478  return getBindingForArray(B, R);
1479  else
1480  return UnknownVal();
1481  }
1482 
1483  // FIXME: handle Vector types.
1484  if (RTy->isVectorType())
1485  return UnknownVal();
1486 
1487  if (const FieldRegion* FR = dyn_cast<FieldRegion>(R))
1488  return CastRetrievedVal(getBindingForField(B, FR), FR, T);
1489 
1490  if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
1491  // FIXME: Here we actually perform an implicit conversion from the loaded
1492  // value to the element type. Eventually we want to compose these values
1493  // more intelligently. For example, an 'element' can encompass multiple
1494  // bound regions (e.g., several bound bytes), or could be a subset of
1495  // a larger value.
1496  return CastRetrievedVal(getBindingForElement(B, ER), ER, T);
1497  }
1498 
1499  if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) {
1500  // FIXME: Here we actually perform an implicit conversion from the loaded
1501  // value to the ivar type. What we should model is stores to ivars
1502  // that blow past the extent of the ivar. If the address of the ivar is
1503  // reinterpretted, it is possible we stored a different value that could
1504  // fit within the ivar. Either we need to cast these when storing them
1505  // or reinterpret them lazily (as we do here).
1506  return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T);
1507  }
1508 
1509  if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
1510  // FIXME: Here we actually perform an implicit conversion from the loaded
1511  // value to the variable type. What we should model is stores to variables
1512  // that blow past the extent of the variable. If the address of the
1513  // variable is reinterpretted, it is possible we stored a different value
1514  // that could fit within the variable. Either we need to cast these when
1515  // storing them or reinterpret them lazily (as we do here).
1516  return CastRetrievedVal(getBindingForVar(B, VR), VR, T);
1517  }
1518 
1519  const SVal *V = B.lookup(R, BindingKey::Direct);
1520 
1521  // Check if the region has a binding.
1522  if (V)
1523  return *V;
1524 
1525  // The location does not have a bound value. This means that it has
1526  // the value it had upon its creation and/or entry to the analyzed
1527  // function/method. These are either symbolic values or 'undefined'.
1528  if (R->hasStackNonParametersStorage()) {
1529  // All stack variables are considered to have undefined values
1530  // upon creation. All heap allocated blocks are considered to
1531  // have undefined values as well unless they are explicitly bound
1532  // to specific values.
1533  return UndefinedVal();
1534  }
1535 
1536  // All other values are symbolic.
1537  return svalBuilder.getRegionValueSymbolVal(R);
1538 }
1539 
1540 static QualType getUnderlyingType(const SubRegion *R) {
1541  QualType RegionTy;
1542  if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R))
1543  RegionTy = TVR->getValueType();
1544 
1545  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1546  RegionTy = SR->getSymbol()->getType();
1547 
1548  return RegionTy;
1549 }
1550 
1551 /// Checks to see if store \p B has a lazy binding for region \p R.
1552 ///
1553 /// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected
1554 /// if there are additional bindings within \p R.
1555 ///
1556 /// Note that unlike RegionStoreManager::findLazyBinding, this will not search
1557 /// for lazy bindings for super-regions of \p R.
1559 getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B,
1560  const SubRegion *R, bool AllowSubregionBindings) {
1561  Optional<SVal> V = B.getDefaultBinding(R);
1562  if (!V)
1563  return None;
1564 
1565  Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>();
1566  if (!LCV)
1567  return None;
1568 
1569  // If the LCV is for a subregion, the types might not match, and we shouldn't
1570  // reuse the binding.
1571  QualType RegionTy = getUnderlyingType(R);
1572  if (!RegionTy.isNull() &&
1573  !RegionTy->isVoidPointerType()) {
1574  QualType SourceRegionTy = LCV->getRegion()->getValueType();
1575  if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy))
1576  return None;
1577  }
1578 
1579  if (!AllowSubregionBindings) {
1580  // If there are any other bindings within this region, we shouldn't reuse
1581  // the top-level binding.
1583  collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R,
1584  /*IncludeAllDefaultBindings=*/true);
1585  if (Bindings.size() > 1)
1586  return None;
1587  }
1588 
1589  return *LCV;
1590 }
1591 
1592 
1593 std::pair<Store, const SubRegion *>
1594 RegionStoreManager::findLazyBinding(RegionBindingsConstRef B,
1595  const SubRegion *R,
1596  const SubRegion *originalRegion) {
1597  if (originalRegion != R) {
1599  getExistingLazyBinding(svalBuilder, B, R, true))
1600  return std::make_pair(V->getStore(), V->getRegion());
1601  }
1602 
1603  typedef std::pair<Store, const SubRegion *> StoreRegionPair;
1604  StoreRegionPair Result = StoreRegionPair();
1605 
1606  if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
1607  Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()),
1608  originalRegion);
1609 
1610  if (Result.second)
1611  Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second);
1612 
1613  } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
1614  Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()),
1615  originalRegion);
1616 
1617  if (Result.second)
1618  Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second);
1619 
1620  } else if (const CXXBaseObjectRegion *BaseReg =
1621  dyn_cast<CXXBaseObjectRegion>(R)) {
1622  // C++ base object region is another kind of region that we should blast
1623  // through to look for lazy compound value. It is like a field region.
1624  Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()),
1625  originalRegion);
1626 
1627  if (Result.second)
1628  Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg,
1629  Result.second);
1630  }
1631 
1632  return Result;
1633 }
1634 
1635 SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B,
1636  const ElementRegion* R) {
1637  // We do not currently model bindings of the CompoundLiteralregion.
1638  if (isa<CompoundLiteralRegion>(R->getBaseRegion()))
1639  return UnknownVal();
1640 
1641  // Check if the region has a binding.
1642  if (const Optional<SVal> &V = B.getDirectBinding(R))
1643  return *V;
1644 
1645  const MemRegion* superR = R->getSuperRegion();
1646 
1647  // Check if the region is an element region of a string literal.
1648  if (const StringRegion *StrR = dyn_cast<StringRegion>(superR)) {
1649  // FIXME: Handle loads from strings where the literal is treated as
1650  // an integer, e.g., *((unsigned int*)"hello")
1651  QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType();
1652  if (!Ctx.hasSameUnqualifiedType(T, R->getElementType()))
1653  return UnknownVal();
1654 
1655  const StringLiteral *Str = StrR->getStringLiteral();
1656  SVal Idx = R->getIndex();
1657  if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) {
1658  int64_t i = CI->getValue().getSExtValue();
1659  // Abort on string underrun. This can be possible by arbitrary
1660  // clients of getBindingForElement().
1661  if (i < 0)
1662  return UndefinedVal();
1663  int64_t length = Str->getLength();
1664  // Technically, only i == length is guaranteed to be null.
1665  // However, such overflows should be caught before reaching this point;
1666  // the only time such an access would be made is if a string literal was
1667  // used to initialize a larger array.
1668  char c = (i >= length) ? '\0' : Str->getCodeUnit(i);
1669  return svalBuilder.makeIntVal(c, T);
1670  }
1671  } else if (const VarRegion *VR = dyn_cast<VarRegion>(superR)) {
1672  // Check if the containing array is const and has an initialized value.
1673  const VarDecl *VD = VR->getDecl();
1674  // Either the array or the array element has to be const.
1675  if (VD->getType().isConstQualified() || R->getElementType().isConstQualified()) {
1676  if (const Expr *Init = VD->getAnyInitializer()) {
1677  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1678  // The array index has to be known.
1679  if (auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) {
1680  int64_t i = CI->getValue().getSExtValue();
1681  // If it is known that the index is out of bounds, we can return
1682  // an undefined value.
1683  if (i < 0)
1684  return UndefinedVal();
1685 
1686  if (auto CAT = Ctx.getAsConstantArrayType(VD->getType()))
1687  if (CAT->getSize().sle(i))
1688  return UndefinedVal();
1689 
1690  // If there is a list, but no init, it must be zero.
1691  if (i >= InitList->getNumInits())
1692  return svalBuilder.makeZeroVal(R->getElementType());
1693 
1694  if (const Expr *ElemInit = InitList->getInit(i))
1695  if (Optional<SVal> V = svalBuilder.getConstantVal(ElemInit))
1696  return *V;
1697  }
1698  }
1699  }
1700  }
1701  }
1702 
1703  // Check for loads from a code text region. For such loads, just give up.
1704  if (isa<CodeTextRegion>(superR))
1705  return UnknownVal();
1706 
1707  // Handle the case where we are indexing into a larger scalar object.
1708  // For example, this handles:
1709  // int x = ...
1710  // char *y = &x;
1711  // return *y;
1712  // FIXME: This is a hack, and doesn't do anything really intelligent yet.
1713  const RegionRawOffset &O = R->getAsArrayOffset();
1714 
1715  // If we cannot reason about the offset, return an unknown value.
1716  if (!O.getRegion())
1717  return UnknownVal();
1718 
1719  if (const TypedValueRegion *baseR =
1720  dyn_cast_or_null<TypedValueRegion>(O.getRegion())) {
1721  QualType baseT = baseR->getValueType();
1722  if (baseT->isScalarType()) {
1723  QualType elemT = R->getElementType();
1724  if (elemT->isScalarType()) {
1725  if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) {
1726  if (const Optional<SVal> &V = B.getDirectBinding(superR)) {
1727  if (SymbolRef parentSym = V->getAsSymbol())
1728  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1729 
1730  if (V->isUnknownOrUndef())
1731  return *V;
1732  // Other cases: give up. We are indexing into a larger object
1733  // that has some value, but we don't know how to handle that yet.
1734  return UnknownVal();
1735  }
1736  }
1737  }
1738  }
1739  }
1740  return getBindingForFieldOrElementCommon(B, R, R->getElementType());
1741 }
1742 
1743 SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B,
1744  const FieldRegion* R) {
1745 
1746  // Check if the region has a binding.
1747  if (const Optional<SVal> &V = B.getDirectBinding(R))
1748  return *V;
1749 
1750  // Is the field declared constant and has an in-class initializer?
1751  const FieldDecl *FD = R->getDecl();
1752  QualType Ty = FD->getType();
1753  if (Ty.isConstQualified())
1754  if (const Expr *Init = FD->getInClassInitializer())
1755  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1756  return *V;
1757 
1758  // If the containing record was initialized, try to get its constant value.
1759  const MemRegion* superR = R->getSuperRegion();
1760  if (const auto *VR = dyn_cast<VarRegion>(superR)) {
1761  const VarDecl *VD = VR->getDecl();
1762  QualType RecordVarTy = VD->getType();
1763  unsigned Index = FD->getFieldIndex();
1764  // Either the record variable or the field has to be const qualified.
1765  if (RecordVarTy.isConstQualified() || Ty.isConstQualified())
1766  if (const Expr *Init = VD->getAnyInitializer())
1767  if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1768  if (Index < InitList->getNumInits()) {
1769  if (const Expr *FieldInit = InitList->getInit(Index))
1770  if (Optional<SVal> V = svalBuilder.getConstantVal(FieldInit))
1771  return *V;
1772  } else {
1773  return svalBuilder.makeZeroVal(Ty);
1774  }
1775  }
1776  }
1777 
1778  return getBindingForFieldOrElementCommon(B, R, Ty);
1779 }
1780 
1782 RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
1783  const MemRegion *superR,
1784  const TypedValueRegion *R,
1785  QualType Ty) {
1786 
1787  if (const Optional<SVal> &D = B.getDefaultBinding(superR)) {
1788  const SVal &val = D.getValue();
1789  if (SymbolRef parentSym = val.getAsSymbol())
1790  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1791 
1792  if (val.isZeroConstant())
1793  return svalBuilder.makeZeroVal(Ty);
1794 
1795  if (val.isUnknownOrUndef())
1796  return val;
1797 
1798  // Lazy bindings are usually handled through getExistingLazyBinding().
1799  // We should unify these two code paths at some point.
1800  if (val.getAs<nonloc::LazyCompoundVal>() ||
1801  val.getAs<nonloc::CompoundVal>())
1802  return val;
1803 
1804  llvm_unreachable("Unknown default value");
1805  }
1806 
1807  return None;
1808 }
1809 
1810 SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion,
1811  RegionBindingsRef LazyBinding) {
1812  SVal Result;
1813  if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion))
1814  Result = getBindingForElement(LazyBinding, ER);
1815  else
1816  Result = getBindingForField(LazyBinding,
1817  cast<FieldRegion>(LazyBindingRegion));
1818 
1819  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1820  // default value for /part/ of an aggregate from a default value for the
1821  // /entire/ aggregate. The most common case of this is when struct Outer
1822  // has as its first member a struct Inner, which is copied in from a stack
1823  // variable. In this case, even if the Outer's default value is symbolic, 0,
1824  // or unknown, it gets overridden by the Inner's default value of undefined.
1825  //
1826  // This is a general problem -- if the Inner is zero-initialized, the Outer
1827  // will now look zero-initialized. The proper way to solve this is with a
1828  // new version of RegionStore that tracks the extent of a binding as well
1829  // as the offset.
1830  //
1831  // This hack only takes care of the undefined case because that can very
1832  // quickly result in a warning.
1833  if (Result.isUndef())
1834  Result = UnknownVal();
1835 
1836  return Result;
1837 }
1838 
1839 SVal
1840 RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
1841  const TypedValueRegion *R,
1842  QualType Ty) {
1843 
1844  // At this point we have already checked in either getBindingForElement or
1845  // getBindingForField if 'R' has a direct binding.
1846 
1847  // Lazy binding?
1848  Store lazyBindingStore = nullptr;
1849  const SubRegion *lazyBindingRegion = nullptr;
1850  std::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R);
1851  if (lazyBindingRegion)
1852  return getLazyBinding(lazyBindingRegion,
1853  getRegionBindings(lazyBindingStore));
1854 
1855  // Record whether or not we see a symbolic index. That can completely
1856  // be out of scope of our lookup.
1857  bool hasSymbolicIndex = false;
1858 
1859  // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1860  // default value for /part/ of an aggregate from a default value for the
1861  // /entire/ aggregate. The most common case of this is when struct Outer
1862  // has as its first member a struct Inner, which is copied in from a stack
1863  // variable. In this case, even if the Outer's default value is symbolic, 0,
1864  // or unknown, it gets overridden by the Inner's default value of undefined.
1865  //
1866  // This is a general problem -- if the Inner is zero-initialized, the Outer
1867  // will now look zero-initialized. The proper way to solve this is with a
1868  // new version of RegionStore that tracks the extent of a binding as well
1869  // as the offset.
1870  //
1871  // This hack only takes care of the undefined case because that can very
1872  // quickly result in a warning.
1873  bool hasPartialLazyBinding = false;
1874 
1875  const SubRegion *SR = R;
1876  while (SR) {
1877  const MemRegion *Base = SR->getSuperRegion();
1878  if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) {
1879  if (D->getAs<nonloc::LazyCompoundVal>()) {
1880  hasPartialLazyBinding = true;
1881  break;
1882  }
1883 
1884  return *D;
1885  }
1886 
1887  if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) {
1888  NonLoc index = ER->getIndex();
1889  if (!index.isConstant())
1890  hasSymbolicIndex = true;
1891  }
1892 
1893  // If our super region is a field or element itself, walk up the region
1894  // hierarchy to see if there is a default value installed in an ancestor.
1895  SR = dyn_cast<SubRegion>(Base);
1896  }
1897 
1898  if (R->hasStackNonParametersStorage()) {
1899  if (isa<ElementRegion>(R)) {
1900  // Currently we don't reason specially about Clang-style vectors. Check
1901  // if superR is a vector and if so return Unknown.
1902  if (const TypedValueRegion *typedSuperR =
1903  dyn_cast<TypedValueRegion>(R->getSuperRegion())) {
1904  if (typedSuperR->getValueType()->isVectorType())
1905  return UnknownVal();
1906  }
1907  }
1908 
1909  // FIXME: We also need to take ElementRegions with symbolic indexes into
1910  // account. This case handles both directly accessing an ElementRegion
1911  // with a symbolic offset, but also fields within an element with
1912  // a symbolic offset.
1913  if (hasSymbolicIndex)
1914  return UnknownVal();
1915 
1916  if (!hasPartialLazyBinding)
1917  return UndefinedVal();
1918  }
1919 
1920  // All other values are symbolic.
1921  return svalBuilder.getRegionValueSymbolVal(R);
1922 }
1923 
1924 SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B,
1925  const ObjCIvarRegion* R) {
1926  // Check if the region has a binding.
1927  if (const Optional<SVal> &V = B.getDirectBinding(R))
1928  return *V;
1929 
1930  const MemRegion *superR = R->getSuperRegion();
1931 
1932  // Check if the super region has a default binding.
1933  if (const Optional<SVal> &V = B.getDefaultBinding(superR)) {
1934  if (SymbolRef parentSym = V->getAsSymbol())
1935  return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1936 
1937  // Other cases: give up.
1938  return UnknownVal();
1939  }
1940 
1941  return getBindingForLazySymbol(R);
1942 }
1943 
1944 SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B,
1945  const VarRegion *R) {
1946 
1947  // Check if the region has a binding.
1948  if (Optional<SVal> V = B.getDirectBinding(R))
1949  return *V;
1950 
1951  if (Optional<SVal> V = B.getDefaultBinding(R))
1952  return *V;
1953 
1954  // Lazily derive a value for the VarRegion.
1955  const VarDecl *VD = R->getDecl();
1956  const MemSpaceRegion *MS = R->getMemorySpace();
1957 
1958  // Arguments are always symbolic.
1959  if (isa<StackArgumentsSpaceRegion>(MS))
1960  return svalBuilder.getRegionValueSymbolVal(R);
1961 
1962  // Is 'VD' declared constant? If so, retrieve the constant value.
1963  if (VD->getType().isConstQualified()) {
1964  if (const Expr *Init = VD->getAnyInitializer()) {
1965  if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1966  return *V;
1967 
1968  // If the variable is const qualified and has an initializer but
1969  // we couldn't evaluate initializer to a value, treat the value as
1970  // unknown.
1971  return UnknownVal();
1972  }
1973  }
1974 
1975  // This must come after the check for constants because closure-captured
1976  // constant variables may appear in UnknownSpaceRegion.
1977  if (isa<UnknownSpaceRegion>(MS))
1978  return svalBuilder.getRegionValueSymbolVal(R);
1979 
1980  if (isa<GlobalsSpaceRegion>(MS)) {
1981  QualType T = VD->getType();
1982 
1983  // Function-scoped static variables are default-initialized to 0; if they
1984  // have an initializer, it would have been processed by now.
1985  // FIXME: This is only true when we're starting analysis from main().
1986  // We're losing a lot of coverage here.
1987  if (isa<StaticGlobalSpaceRegion>(MS))
1988  return svalBuilder.makeZeroVal(T);
1989 
1990  if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) {
1991  assert(!V->getAs<nonloc::LazyCompoundVal>());
1992  return V.getValue();
1993  }
1994 
1995  return svalBuilder.getRegionValueSymbolVal(R);
1996  }
1997 
1998  return UndefinedVal();
1999 }
2000 
2001 SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
2002  // All other values are symbolic.
2003  return svalBuilder.getRegionValueSymbolVal(R);
2004 }
2005 
2006 const RegionStoreManager::SValListTy &
2007 RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) {
2008  // First, check the cache.
2009  LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData());
2010  if (I != LazyBindingsMap.end())
2011  return I->second;
2012 
2013  // If we don't have a list of values cached, start constructing it.
2014  SValListTy List;
2015 
2016  const SubRegion *LazyR = LCV.getRegion();
2017  RegionBindingsRef B = getRegionBindings(LCV.getStore());
2018 
2019  // If this region had /no/ bindings at the time, there are no interesting
2020  // values to return.
2021  const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion());
2022  if (!Cluster)
2023  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2024 
2026  collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR,
2027  /*IncludeAllDefaultBindings=*/true);
2028  for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
2029  E = Bindings.end();
2030  I != E; ++I) {
2031  SVal V = I->second;
2032  if (V.isUnknownOrUndef() || V.isConstant())
2033  continue;
2034 
2035  if (Optional<nonloc::LazyCompoundVal> InnerLCV =
2036  V.getAs<nonloc::LazyCompoundVal>()) {
2037  const SValListTy &InnerList = getInterestingValues(*InnerLCV);
2038  List.insert(List.end(), InnerList.begin(), InnerList.end());
2039  continue;
2040  }
2041 
2042  List.push_back(V);
2043  }
2044 
2045  return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2046 }
2047 
2048 NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B,
2049  const TypedValueRegion *R) {
2051  getExistingLazyBinding(svalBuilder, B, R, false))
2052  return *V;
2053 
2054  return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R);
2055 }
2056 
2057 static bool isRecordEmpty(const RecordDecl *RD) {
2058  if (!RD->field_empty())
2059  return false;
2060  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD))
2061  return CRD->getNumBases() == 0;
2062  return true;
2063 }
2064 
2065 SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B,
2066  const TypedValueRegion *R) {
2067  const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl();
2068  if (!RD->getDefinition() || isRecordEmpty(RD))
2069  return UnknownVal();
2070 
2071  return createLazyBinding(B, R);
2072 }
2073 
2074 SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B,
2075  const TypedValueRegion *R) {
2076  assert(Ctx.getAsConstantArrayType(R->getValueType()) &&
2077  "Only constant array types can have compound bindings.");
2078 
2079  return createLazyBinding(B, R);
2080 }
2081 
2082 bool RegionStoreManager::includedInBindings(Store store,
2083  const MemRegion *region) const {
2084  RegionBindingsRef B = getRegionBindings(store);
2085  region = region->getBaseRegion();
2086 
2087  // Quick path: if the base is the head of a cluster, the region is live.
2088  if (B.lookup(region))
2089  return true;
2090 
2091  // Slow path: if the region is the VALUE of any binding, it is live.
2092  for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) {
2093  const ClusterBindings &Cluster = RI.getData();
2094  for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2095  CI != CE; ++CI) {
2096  const SVal &D = CI.getData();
2097  if (const MemRegion *R = D.getAsRegion())
2098  if (R->getBaseRegion() == region)
2099  return true;
2100  }
2101  }
2102 
2103  return false;
2104 }
2105 
2106 //===----------------------------------------------------------------------===//
2107 // Binding values to regions.
2108 //===----------------------------------------------------------------------===//
2109 
2110 StoreRef RegionStoreManager::killBinding(Store ST, Loc L) {
2111  if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>())
2112  if (const MemRegion* R = LV->getRegion())
2113  return StoreRef(getRegionBindings(ST).removeBinding(R)
2114  .asImmutableMap()
2115  .getRootWithoutRetain(),
2116  *this);
2117 
2118  return StoreRef(ST, *this);
2119 }
2120 
2121 RegionBindingsRef
2122 RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) {
2123  if (L.getAs<loc::ConcreteInt>())
2124  return B;
2125 
2126  // If we get here, the location should be a region.
2127  const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion();
2128 
2129  // Check if the region is a struct region.
2130  if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) {
2131  QualType Ty = TR->getValueType();
2132  if (Ty->isArrayType())
2133  return bindArray(B, TR, V);
2134  if (Ty->isStructureOrClassType())
2135  return bindStruct(B, TR, V);
2136  if (Ty->isVectorType())
2137  return bindVector(B, TR, V);
2138  if (Ty->isUnionType())
2139  return bindAggregate(B, TR, V);
2140  }
2141 
2142  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
2143  // Binding directly to a symbolic region should be treated as binding
2144  // to element 0.
2145  QualType T = SR->getSymbol()->getType();
2146  if (T->isAnyPointerType() || T->isReferenceType())
2147  T = T->getPointeeType();
2148 
2149  R = GetElementZeroRegion(SR, T);
2150  }
2151 
2152  assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) &&
2153  "'this' pointer is not an l-value and is not assignable");
2154 
2155  // Clear out bindings that may overlap with this binding.
2156  RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R));
2157  return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V);
2158 }
2159 
2160 RegionBindingsRef
2161 RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B,
2162  const MemRegion *R,
2163  QualType T) {
2164  SVal V;
2165 
2166  if (Loc::isLocType(T))
2167  V = svalBuilder.makeNull();
2168  else if (T->isIntegralOrEnumerationType())
2169  V = svalBuilder.makeZeroVal(T);
2170  else if (T->isStructureOrClassType() || T->isArrayType()) {
2171  // Set the default value to a zero constant when it is a structure
2172  // or array. The type doesn't really matter.
2173  V = svalBuilder.makeZeroVal(Ctx.IntTy);
2174  }
2175  else {
2176  // We can't represent values of this type, but we still need to set a value
2177  // to record that the region has been initialized.
2178  // If this assertion ever fires, a new case should be added above -- we
2179  // should know how to default-initialize any value we can symbolicate.
2180  assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
2181  V = UnknownVal();
2182  }
2183 
2184  return B.addBinding(R, BindingKey::Default, V);
2185 }
2186 
2187 RegionBindingsRef
2188 RegionStoreManager::bindArray(RegionBindingsConstRef B,
2189  const TypedValueRegion* R,
2190  SVal Init) {
2191 
2192  const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType()));
2193  QualType ElementTy = AT->getElementType();
2194  Optional<uint64_t> Size;
2195 
2196  if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT))
2197  Size = CAT->getSize().getZExtValue();
2198 
2199  // Check if the init expr is a literal. If so, bind the rvalue instead.
2200  // FIXME: It's not responsibility of the Store to transform this lvalue
2201  // to rvalue. ExprEngine or maybe even CFG should do this before binding.
2202  if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) {
2203  SVal V = getBinding(B.asStore(), *MRV, R->getValueType());
2204  return bindAggregate(B, R, V);
2205  }
2206 
2207  // Handle lazy compound values.
2208  if (Init.getAs<nonloc::LazyCompoundVal>())
2209  return bindAggregate(B, R, Init);
2210 
2211  if (Init.isUnknown())
2212  return bindAggregate(B, R, UnknownVal());
2213 
2214  // Remaining case: explicit compound values.
2215  const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>();
2216  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2217  uint64_t i = 0;
2218 
2219  RegionBindingsRef NewB(B);
2220 
2221  for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) {
2222  // The init list might be shorter than the array length.
2223  if (VI == VE)
2224  break;
2225 
2226  const NonLoc &Idx = svalBuilder.makeArrayIndex(i);
2227  const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx);
2228 
2229  if (ElementTy->isStructureOrClassType())
2230  NewB = bindStruct(NewB, ER, *VI);
2231  else if (ElementTy->isArrayType())
2232  NewB = bindArray(NewB, ER, *VI);
2233  else
2234  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2235  }
2236 
2237  // If the init list is shorter than the array length (or the array has
2238  // variable length), set the array default value. Values that are already set
2239  // are not overwritten.
2240  if (!Size.hasValue() || i < Size.getValue())
2241  NewB = setImplicitDefaultValue(NewB, R, ElementTy);
2242 
2243  return NewB;
2244 }
2245 
2246 RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B,
2247  const TypedValueRegion* R,
2248  SVal V) {
2249  QualType T = R->getValueType();
2250  assert(T->isVectorType());
2251  const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs.
2252 
2253  // Handle lazy compound values and symbolic values.
2254  if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>())
2255  return bindAggregate(B, R, V);
2256 
2257  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2258  // that we are binding symbolic struct value. Kill the field values, and if
2259  // the value is symbolic go and bind it as a "default" binding.
2260  if (!V.getAs<nonloc::CompoundVal>()) {
2261  return bindAggregate(B, R, UnknownVal());
2262  }
2263 
2264  QualType ElemType = VT->getElementType();
2265  nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>();
2266  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2267  unsigned index = 0, numElements = VT->getNumElements();
2268  RegionBindingsRef NewB(B);
2269 
2270  for ( ; index != numElements ; ++index) {
2271  if (VI == VE)
2272  break;
2273 
2274  NonLoc Idx = svalBuilder.makeArrayIndex(index);
2275  const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx);
2276 
2277  if (ElemType->isArrayType())
2278  NewB = bindArray(NewB, ER, *VI);
2279  else if (ElemType->isStructureOrClassType())
2280  NewB = bindStruct(NewB, ER, *VI);
2281  else
2282  NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2283  }
2284  return NewB;
2285 }
2286 
2288 RegionStoreManager::tryBindSmallStruct(RegionBindingsConstRef B,
2289  const TypedValueRegion *R,
2290  const RecordDecl *RD,
2291  nonloc::LazyCompoundVal LCV) {
2292  FieldVector Fields;
2293 
2294  if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(RD))
2295  if (Class->getNumBases() != 0 || Class->getNumVBases() != 0)
2296  return None;
2297 
2298  for (const auto *FD : RD->fields()) {
2299  if (FD->isUnnamedBitfield())
2300  continue;
2301 
2302  // If there are too many fields, or if any of the fields are aggregates,
2303  // just use the LCV as a default binding.
2304  if (Fields.size() == SmallStructLimit)
2305  return None;
2306 
2307  QualType Ty = FD->getType();
2308  if (!(Ty->isScalarType() || Ty->isReferenceType()))
2309  return None;
2310 
2311  Fields.push_back(FD);
2312  }
2313 
2314  RegionBindingsRef NewB = B;
2315 
2316  for (FieldVector::iterator I = Fields.begin(), E = Fields.end(); I != E; ++I){
2317  const FieldRegion *SourceFR = MRMgr.getFieldRegion(*I, LCV.getRegion());
2318  SVal V = getBindingForField(getRegionBindings(LCV.getStore()), SourceFR);
2319 
2320  const FieldRegion *DestFR = MRMgr.getFieldRegion(*I, R);
2321  NewB = bind(NewB, loc::MemRegionVal(DestFR), V);
2322  }
2323 
2324  return NewB;
2325 }
2326 
2327 RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B,
2328  const TypedValueRegion* R,
2329  SVal V) {
2330  if (!Features.supportsFields())
2331  return B;
2332 
2333  QualType T = R->getValueType();
2334  assert(T->isStructureOrClassType());
2335 
2336  const RecordType* RT = T->getAs<RecordType>();
2337  const RecordDecl *RD = RT->getDecl();
2338 
2339  if (!RD->isCompleteDefinition())
2340  return B;
2341 
2342  // Handle lazy compound values and symbolic values.
2344  V.getAs<nonloc::LazyCompoundVal>()) {
2345  if (Optional<RegionBindingsRef> NewB = tryBindSmallStruct(B, R, RD, *LCV))
2346  return *NewB;
2347  return bindAggregate(B, R, V);
2348  }
2349  if (V.getAs<nonloc::SymbolVal>())
2350  return bindAggregate(B, R, V);
2351 
2352  // We may get non-CompoundVal accidentally due to imprecise cast logic or
2353  // that we are binding symbolic struct value. Kill the field values, and if
2354  // the value is symbolic go and bind it as a "default" binding.
2355  if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>())
2356  return bindAggregate(B, R, UnknownVal());
2357 
2358  // The raw CompoundVal is essentially a symbolic InitListExpr: an (immutable)
2359  // list of other values. It appears pretty much only when there's an actual
2360  // initializer list expression in the program, and the analyzer tries to
2361  // unwrap it as soon as possible.
2362  // This code is where such unwrap happens: when the compound value is put into
2363  // the object that it was supposed to initialize (it's an *initializer* list,
2364  // after all), instead of binding the whole value to the whole object, we bind
2365  // sub-values to sub-objects. Sub-values may themselves be compound values,
2366  // and in this case the procedure becomes recursive.
2367  // FIXME: The annoying part about compound values is that they don't carry
2368  // any sort of information about which value corresponds to which sub-object.
2369  // It's simply a list of values in the middle of nowhere; we expect to match
2370  // them to sub-objects, essentially, "by index": first value binds to
2371  // the first field, second value binds to the second field, etc.
2372  // It would have been much safer to organize non-lazy compound values as
2373  // a mapping from fields/bases to values.
2374  const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>();
2375  nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2376 
2377  RegionBindingsRef NewB(B);
2378 
2379  // In C++17 aggregates may have base classes, handle those as well.
2380  // They appear before fields in the initializer list / compound value.
2381  if (const auto *CRD = dyn_cast<CXXRecordDecl>(RD)) {
2382  // If the object was constructed with a constructor, its value is a
2383  // LazyCompoundVal. If it's a raw CompoundVal, it means that we're
2384  // performing aggregate initialization. The only exception from this
2385  // rule is sending an Objective-C++ message that returns a C++ object
2386  // to a nil receiver; in this case the semantics is to return a
2387  // zero-initialized object even if it's a C++ object that doesn't have
2388  // this sort of constructor; the CompoundVal is empty in this case.
2389  assert((CRD->isAggregate() || (Ctx.getLangOpts().ObjC && VI == VE)) &&
2390  "Non-aggregates are constructed with a constructor!");
2391 
2392  for (const auto &B : CRD->bases()) {
2393  // (Multiple inheritance is fine though.)
2394  assert(!B.isVirtual() && "Aggregates cannot have virtual base classes!");
2395 
2396  if (VI == VE)
2397  break;
2398 
2399  QualType BTy = B.getType();
2400  assert(BTy->isStructureOrClassType() && "Base classes must be classes!");
2401 
2402  const CXXRecordDecl *BRD = BTy->getAsCXXRecordDecl();
2403  assert(BRD && "Base classes must be C++ classes!");
2404 
2405  const CXXBaseObjectRegion *BR =
2406  MRMgr.getCXXBaseObjectRegion(BRD, R, /*IsVirtual=*/false);
2407 
2408  NewB = bindStruct(NewB, BR, *VI);
2409 
2410  ++VI;
2411  }
2412  }
2413 
2415 
2416  for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
2417 
2418  if (VI == VE)
2419  break;
2420 
2421  // Skip any unnamed bitfields to stay in sync with the initializers.
2422  if (FI->isUnnamedBitfield())
2423  continue;
2424 
2425  QualType FTy = FI->getType();
2426  const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R);
2427 
2428  if (FTy->isArrayType())
2429  NewB = bindArray(NewB, FR, *VI);
2430  else if (FTy->isStructureOrClassType())
2431  NewB = bindStruct(NewB, FR, *VI);
2432  else
2433  NewB = bind(NewB, loc::MemRegionVal(FR), *VI);
2434  ++VI;
2435  }
2436 
2437  // There may be fewer values in the initialize list than the fields of struct.
2438  if (FI != FE) {
2439  NewB = NewB.addBinding(R, BindingKey::Default,
2440  svalBuilder.makeIntVal(0, false));
2441  }
2442 
2443  return NewB;
2444 }
2445 
2446 RegionBindingsRef
2447 RegionStoreManager::bindAggregate(RegionBindingsConstRef B,
2448  const TypedRegion *R,
2449  SVal Val) {
2450  // Remove the old bindings, using 'R' as the root of all regions
2451  // we will invalidate. Then add the new binding.
2452  return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val);
2453 }
2454 
2455 //===----------------------------------------------------------------------===//
2456 // State pruning.
2457 //===----------------------------------------------------------------------===//
2458 
2459 namespace {
2460 class RemoveDeadBindingsWorker
2461  : public ClusterAnalysis<RemoveDeadBindingsWorker> {
2463  SymbolReaper &SymReaper;
2464  const StackFrameContext *CurrentLCtx;
2465 
2466 public:
2467  RemoveDeadBindingsWorker(RegionStoreManager &rm,
2468  ProgramStateManager &stateMgr,
2469  RegionBindingsRef b, SymbolReaper &symReaper,
2470  const StackFrameContext *LCtx)
2471  : ClusterAnalysis<RemoveDeadBindingsWorker>(rm, stateMgr, b),
2472  SymReaper(symReaper), CurrentLCtx(LCtx) {}
2473 
2474  // Called by ClusterAnalysis.
2475  void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C);
2476  void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
2477  using ClusterAnalysis<RemoveDeadBindingsWorker>::VisitCluster;
2478 
2479  using ClusterAnalysis::AddToWorkList;
2480 
2481  bool AddToWorkList(const MemRegion *R);
2482 
2483  bool UpdatePostponed();
2484  void VisitBinding(SVal V);
2485 };
2486 }
2487 
2488 bool RemoveDeadBindingsWorker::AddToWorkList(const MemRegion *R) {
2489  const MemRegion *BaseR = R->getBaseRegion();
2490  return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
2491 }
2492 
2493 void RemoveDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
2494  const ClusterBindings &C) {
2495 
2496  if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) {
2497  if (SymReaper.isLive(VR))
2498  AddToWorkList(baseR, &C);
2499 
2500  return;
2501  }
2502 
2503  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) {
2504  if (SymReaper.isLive(SR->getSymbol()))
2505  AddToWorkList(SR, &C);
2506  else
2507  Postponed.push_back(SR);
2508 
2509  return;
2510  }
2511 
2512  if (isa<NonStaticGlobalSpaceRegion>(baseR)) {
2513  AddToWorkList(baseR, &C);
2514  return;
2515  }
2516 
2517  // CXXThisRegion in the current or parent location context is live.
2518  if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) {
2519  const auto *StackReg =
2520  cast<StackArgumentsSpaceRegion>(TR->getSuperRegion());
2521  const StackFrameContext *RegCtx = StackReg->getStackFrame();
2522  if (CurrentLCtx &&
2523  (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx)))
2524  AddToWorkList(TR, &C);
2525  }
2526 }
2527 
2528 void RemoveDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
2529  const ClusterBindings *C) {
2530  if (!C)
2531  return;
2532 
2533  // Mark the symbol for any SymbolicRegion with live bindings as live itself.
2534  // This means we should continue to track that symbol.
2535  if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR))
2536  SymReaper.markLive(SymR->getSymbol());
2537 
2538  for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) {
2539  // Element index of a binding key is live.
2540  SymReaper.markElementIndicesLive(I.getKey().getRegion());
2541 
2542  VisitBinding(I.getData());
2543  }
2544 }
2545 
2546 void RemoveDeadBindingsWorker::VisitBinding(SVal V) {
2547  // Is it a LazyCompoundVal? All referenced regions are live as well.
2549  V.getAs<nonloc::LazyCompoundVal>()) {
2550 
2551  const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
2552 
2553  for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
2554  E = Vals.end();
2555  I != E; ++I)
2556  VisitBinding(*I);
2557 
2558  return;
2559  }
2560 
2561  // If V is a region, then add it to the worklist.
2562  if (const MemRegion *R = V.getAsRegion()) {
2563  AddToWorkList(R);
2564  SymReaper.markLive(R);
2565 
2566  // All regions captured by a block are also live.
2567  if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) {
2568  BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(),
2569  E = BR->referenced_vars_end();
2570  for ( ; I != E; ++I)
2571  AddToWorkList(I.getCapturedRegion());
2572  }
2573  }
2574 
2575 
2576  // Update the set of live symbols.
2577  for (auto SI = V.symbol_begin(), SE = V.symbol_end(); SI!=SE; ++SI)
2578  SymReaper.markLive(*SI);
2579 }
2580 
2581 bool RemoveDeadBindingsWorker::UpdatePostponed() {
2582  // See if any postponed SymbolicRegions are actually live now, after
2583  // having done a scan.
2584  bool Changed = false;
2585 
2586  for (auto I = Postponed.begin(), E = Postponed.end(); I != E; ++I) {
2587  if (const SymbolicRegion *SR = *I) {
2588  if (SymReaper.isLive(SR->getSymbol())) {
2589  Changed |= AddToWorkList(SR);
2590  *I = nullptr;
2591  }
2592  }
2593  }
2594 
2595  return Changed;
2596 }
2597 
2598 StoreRef RegionStoreManager::removeDeadBindings(Store store,
2599  const StackFrameContext *LCtx,
2600  SymbolReaper& SymReaper) {
2601  RegionBindingsRef B = getRegionBindings(store);
2602  RemoveDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
2603  W.GenerateClusters();
2604 
2605  // Enqueue the region roots onto the worklist.
2606  for (SymbolReaper::region_iterator I = SymReaper.region_begin(),
2607  E = SymReaper.region_end(); I != E; ++I) {
2608  W.AddToWorkList(*I);
2609  }
2610 
2611  do W.RunWorkList(); while (W.UpdatePostponed());
2612 
2613  // We have now scanned the store, marking reachable regions and symbols
2614  // as live. We now remove all the regions that are dead from the store
2615  // as well as update DSymbols with the set symbols that are now dead.
2616  for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
2617  const MemRegion *Base = I.getKey();
2618 
2619  // If the cluster has been visited, we know the region has been marked.
2620  // Otherwise, remove the dead entry.
2621  if (!W.isVisited(Base))
2622  B = B.remove(Base);
2623  }
2624 
2625  return StoreRef(B.asStore(), *this);
2626 }
2627 
2628 //===----------------------------------------------------------------------===//
2629 // Utility methods.
2630 //===----------------------------------------------------------------------===//
2631 
2632 void RegionStoreManager::printJson(raw_ostream &Out, Store S, const char *NL,
2633  unsigned int Space, bool IsDot) const {
2634  RegionBindingsRef Bindings = getRegionBindings(S);
2635 
2636  Indent(Out, Space, IsDot) << "\"store\": ";
2637 
2638  if (Bindings.isEmpty()) {
2639  Out << "null," << NL;
2640  return;
2641  }
2642 
2643  Out << "{ \"pointer\": \"" << Bindings.asStore() << "\", \"items\": [" << NL;
2644  Bindings.printJson(Out, NL, Space + 1, IsDot);
2645  Indent(Out, Space, IsDot) << "]}," << NL;
2646 }
A (possibly-)qualified type.
Definition: Type.h:643
bool isArrayType() const
Definition: Type.h:6440
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
const SymExpr * SymbolRef
internal::Matcher< Stmt > StatementMatcher
Definition: ASTMatchers.h:147
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:505
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:3949
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:2844
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:1209
QualType getElementType() const
Definition: Type.h:2879
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6851
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:3849
const internal::VariadicDynCastAllOfMatcher< Decl, VarDecl > varDecl
Matches variable declarations.
long i
Definition: xmmintrin.h:1456
std::unique_ptr< StoreManager > CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr)
Represents a struct/union/class.
Definition: Decl.h:3626
llvm::ImmutableMap< BindingKey, SVal > ClusterBindings
SmallVector< const FieldDecl *, 8 > FieldVector
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:154
llvm::ImmutableList< SVal >::iterator iterator
Definition: SVals.h:467
RecordDecl * getDefinition() const
Returns the RecordDecl that actually defines this struct/union/class.
Definition: Decl.h:3831
field_range fields() const
Definition: Decl.h:3841
Represents a member of a struct/union/class.
Definition: Decl.h:2607
static bool canSymbolicate(QualType T)
bool isReferenceType() const
Definition: Type.h:6396
c
Definition: emmintrin.h:306
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:6747
static bool isLocType(QualType T)
Definition: SVals.h:329
unsigned getLength() const
Definition: Expr.h:1793
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:37
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
b
Definition: emmintrin.h:321
SmallVector< const MemRegion *, 8 > InvalidatedRegions
Definition: Store.h:209
bool isScalarType() const
Definition: Type.h:6732
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:1636
static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields)
When applied to a MemSpaceRegion, indicates the entire memory space should be invalidated.
Definition: MemRegion.h:1464
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:1035
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6916
#define V(N, I)
Definition: ASTContext.h:2907
__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:1779
static CharUnits fromQuantity(QuantityType Quantity)
fromQuantity - Construct a CharUnits quantity from a raw integer type.
Definition: CharUnits.h:62
Represents a GCC generic vector type.
Definition: Type.h:3200
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:475
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:6201
bool isVoidPointerType() const
Definition: Type.cpp:469
Maps string IDs to AST nodes matched by parts of a matcher.
Definition: ASTMatchers.h:103
r
Definition: emmintrin.h:563
bool isStructureOrClassType() const
Definition: Type.cpp:461
Kind
static QualType getUnderlyingType(const SubRegion *R)
Expr * getInClassInitializer() const
Get the C++11 default member initializer for this member, or null if one has not been set...
Definition: Decl.h:2754
__m64_union t
Definition: emmintrin.h:2059
bool isAnyPointerType() const
Definition: Type.h:6388
bool operator<(DeclarationName LHS, DeclarationName RHS)
Ordering on two declaration names.
bool isVectorType() const
Definition: Type.h:6476
Tells that a region&#39;s contents is not changed.
Definition: MemRegion.h:1454
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
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:4438
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:14425
__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:300
bool isVoidType() const
Definition: Type.h:6643
StringLiteral - This represents a string literal expression, e.g.
Definition: Expr.h:1681
Defines the clang::TargetInfo interface.
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:647
#define true
Definition: stdbool.h:16
Represents the canonical version of C arrays with a specified constant size.
Definition: Type.h:2904