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"
19 #include "clang/ASTMatchers/ASTMatchFinder.h"
20 #include "clang/Analysis/Analyses/LiveVariables.h"
21 #include "clang/Analysis/AnalysisDeclContext.h"
22 #include "clang/Basic/JsonSupport.h"
23 #include "clang/Basic/TargetInfo.h"
24 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
25 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
26 #include "clang/StaticAnalyzer/Core/PathSensitive/DynamicSize.h"
27 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
28 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
29 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
30 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
31 #include "llvm/ADT/ImmutableMap.h"
32 #include "llvm/ADT/Optional.h"
33 #include "llvm/Support/raw_ostream.h"
34 #include <utility>
35
36 using namespace clang;
37 using namespace ento;
38
39 //===----------------------------------------------------------------------===//
40 // Representation of binding keys.
41 //===----------------------------------------------------------------------===//
42
43 namespace {
44 class BindingKey {
45 public:
46 enum Kind { Default = 0x0, Direct = 0x1 };
47 private:
48 enum { Symbolic = 0x2 };
49
50 llvm::PointerIntPair<const MemRegion *, 2> P;
51 uint64_t Data;
52
53 /// Create a key for a binding to region \p r, which has a symbolic offset
54 /// from region \p Base.
BindingKey(const SubRegion * r,const SubRegion * Base,Kind k)55 explicit BindingKey(const SubRegion *r, const SubRegion *Base, Kind k)
56 : P(r, k | Symbolic), Data(reinterpret_cast<uintptr_t>(Base)) {
57 assert(r && Base && "Must have known regions.");
58 assert(getConcreteOffsetRegion() == Base && "Failed to store base region");
59 }
60
61 /// Create a key for a binding at \p offset from base region \p r.
BindingKey(const MemRegion * r,uint64_t offset,Kind k)62 explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k)
63 : P(r, k), Data(offset) {
64 assert(r && "Must have known regions.");
65 assert(getOffset() == offset && "Failed to store offset");
66 assert((r == r->getBaseRegion() || isa<ObjCIvarRegion>(r) ||
67 isa <CXXDerivedObjectRegion>(r)) &&
68 "Not a base");
69 }
70 public:
71
isDirect() const72 bool isDirect() const { return P.getInt() & Direct; }
hasSymbolicOffset() const73 bool hasSymbolicOffset() const { return P.getInt() & Symbolic; }
74
getRegion() const75 const MemRegion *getRegion() const { return P.getPointer(); }
getOffset() const76 uint64_t getOffset() const {
77 assert(!hasSymbolicOffset());
78 return Data;
79 }
80
getConcreteOffsetRegion() const81 const SubRegion *getConcreteOffsetRegion() const {
82 assert(hasSymbolicOffset());
83 return reinterpret_cast<const SubRegion *>(static_cast<uintptr_t>(Data));
84 }
85
getBaseRegion() const86 const MemRegion *getBaseRegion() const {
87 if (hasSymbolicOffset())
88 return getConcreteOffsetRegion()->getBaseRegion();
89 return getRegion()->getBaseRegion();
90 }
91
Profile(llvm::FoldingSetNodeID & ID) const92 void Profile(llvm::FoldingSetNodeID& ID) const {
93 ID.AddPointer(P.getOpaqueValue());
94 ID.AddInteger(Data);
95 }
96
97 static BindingKey Make(const MemRegion *R, Kind k);
98
operator <(const BindingKey & X) const99 bool operator<(const BindingKey &X) const {
100 if (P.getOpaqueValue() < X.P.getOpaqueValue())
101 return true;
102 if (P.getOpaqueValue() > X.P.getOpaqueValue())
103 return false;
104 return Data < X.Data;
105 }
106
operator ==(const BindingKey & X) const107 bool operator==(const BindingKey &X) const {
108 return P.getOpaqueValue() == X.P.getOpaqueValue() &&
109 Data == X.Data;
110 }
111
112 LLVM_DUMP_METHOD void dump() const;
113 };
114 } // end anonymous namespace
115
Make(const MemRegion * R,Kind k)116 BindingKey BindingKey::Make(const MemRegion *R, Kind k) {
117 const RegionOffset &RO = R->getAsOffset();
118 if (RO.hasSymbolicOffset())
119 return BindingKey(cast<SubRegion>(R), cast<SubRegion>(RO.getRegion()), k);
120
121 return BindingKey(RO.getRegion(), RO.getOffset(), k);
122 }
123
124 namespace llvm {
operator <<(raw_ostream & Out,BindingKey K)125 static inline raw_ostream &operator<<(raw_ostream &Out, BindingKey K) {
126 Out << "\"kind\": \"" << (K.isDirect() ? "Direct" : "Default")
127 << "\", \"offset\": ";
128
129 if (!K.hasSymbolicOffset())
130 Out << K.getOffset();
131 else
132 Out << "null";
133
134 return Out;
135 }
136
137 } // namespace llvm
138
139 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const140 void BindingKey::dump() const { llvm::errs() << *this; }
141 #endif
142
143 //===----------------------------------------------------------------------===//
144 // Actual Store type.
145 //===----------------------------------------------------------------------===//
146
147 typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings;
148 typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef;
149 typedef std::pair<BindingKey, SVal> BindingPair;
150
151 typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings>
152 RegionBindings;
153
154 namespace {
155 class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *,
156 ClusterBindings> {
157 ClusterBindings::Factory *CBFactory;
158
159 // This flag indicates whether the current bindings are within the analysis
160 // that has started from main(). It affects how we perform loads from
161 // global variables that have initializers: if we have observed the
162 // program execution from the start and we know that these variables
163 // have not been overwritten yet, we can be sure that their initializers
164 // are still relevant. This flag never gets changed when the bindings are
165 // updated, so it could potentially be moved into RegionStoreManager
166 // (as if it's the same bindings but a different loading procedure)
167 // however that would have made the manager needlessly stateful.
168 bool IsMainAnalysis;
169
170 public:
171 typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>
172 ParentTy;
173
RegionBindingsRef(ClusterBindings::Factory & CBFactory,const RegionBindings::TreeTy * T,RegionBindings::TreeTy::Factory * F,bool IsMainAnalysis)174 RegionBindingsRef(ClusterBindings::Factory &CBFactory,
175 const RegionBindings::TreeTy *T,
176 RegionBindings::TreeTy::Factory *F,
177 bool IsMainAnalysis)
178 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F),
179 CBFactory(&CBFactory), IsMainAnalysis(IsMainAnalysis) {}
180
RegionBindingsRef(const ParentTy & P,ClusterBindings::Factory & CBFactory,bool IsMainAnalysis)181 RegionBindingsRef(const ParentTy &P,
182 ClusterBindings::Factory &CBFactory,
183 bool IsMainAnalysis)
184 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P),
185 CBFactory(&CBFactory), IsMainAnalysis(IsMainAnalysis) {}
186
add(key_type_ref K,data_type_ref D) const187 RegionBindingsRef add(key_type_ref K, data_type_ref D) const {
188 return RegionBindingsRef(static_cast<const ParentTy *>(this)->add(K, D),
189 *CBFactory, IsMainAnalysis);
190 }
191
remove(key_type_ref K) const192 RegionBindingsRef remove(key_type_ref K) const {
193 return RegionBindingsRef(static_cast<const ParentTy *>(this)->remove(K),
194 *CBFactory, IsMainAnalysis);
195 }
196
197 RegionBindingsRef addBinding(BindingKey K, SVal V) const;
198
199 RegionBindingsRef addBinding(const MemRegion *R,
200 BindingKey::Kind k, SVal V) const;
201
202 const SVal *lookup(BindingKey K) const;
203 const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const;
204 using llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>::lookup;
205
206 RegionBindingsRef removeBinding(BindingKey K);
207
208 RegionBindingsRef removeBinding(const MemRegion *R,
209 BindingKey::Kind k);
210
removeBinding(const MemRegion * R)211 RegionBindingsRef removeBinding(const MemRegion *R) {
212 return removeBinding(R, BindingKey::Direct).
213 removeBinding(R, BindingKey::Default);
214 }
215
216 Optional<SVal> getDirectBinding(const MemRegion *R) const;
217
218 /// getDefaultBinding - Returns an SVal* representing an optional default
219 /// binding associated with a region and its subregions.
220 Optional<SVal> getDefaultBinding(const MemRegion *R) const;
221
222 /// Return the internal tree as a Store.
asStore() const223 Store asStore() const {
224 llvm::PointerIntPair<Store, 1, bool> Ptr = {
225 asImmutableMap().getRootWithoutRetain(), IsMainAnalysis};
226 return reinterpret_cast<Store>(Ptr.getOpaqueValue());
227 }
228
isMainAnalysis() const229 bool isMainAnalysis() const {
230 return IsMainAnalysis;
231 }
232
printJson(raw_ostream & Out,const char * NL="\\n",unsigned int Space=0,bool IsDot=false) const233 void printJson(raw_ostream &Out, const char *NL = "\n",
234 unsigned int Space = 0, bool IsDot = false) const {
235 for (iterator I = begin(); I != end(); ++I) {
236 // TODO: We might need a .printJson for I.getKey() as well.
237 Indent(Out, Space, IsDot)
238 << "{ \"cluster\": \"" << I.getKey() << "\", \"pointer\": \""
239 << (const void *)I.getKey() << "\", \"items\": [" << NL;
240
241 ++Space;
242 const ClusterBindings &CB = I.getData();
243 for (ClusterBindings::iterator CI = CB.begin(); CI != CB.end(); ++CI) {
244 Indent(Out, Space, IsDot) << "{ " << CI.getKey() << ", \"value\": ";
245 CI.getData().printJson(Out, /*AddQuotes=*/true);
246 Out << " }";
247 if (std::next(CI) != CB.end())
248 Out << ',';
249 Out << NL;
250 }
251
252 --Space;
253 Indent(Out, Space, IsDot) << "]}";
254 if (std::next(I) != end())
255 Out << ',';
256 Out << NL;
257 }
258 }
259
dump() const260 LLVM_DUMP_METHOD void dump() const { printJson(llvm::errs()); }
261 };
262 } // end anonymous namespace
263
264 typedef const RegionBindingsRef& RegionBindingsConstRef;
265
getDirectBinding(const MemRegion * R) const266 Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const {
267 return Optional<SVal>::create(lookup(R, BindingKey::Direct));
268 }
269
getDefaultBinding(const MemRegion * R) const270 Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const {
271 return Optional<SVal>::create(lookup(R, BindingKey::Default));
272 }
273
addBinding(BindingKey K,SVal V) const274 RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const {
275 const MemRegion *Base = K.getBaseRegion();
276
277 const ClusterBindings *ExistingCluster = lookup(Base);
278 ClusterBindings Cluster =
279 (ExistingCluster ? *ExistingCluster : CBFactory->getEmptyMap());
280
281 ClusterBindings NewCluster = CBFactory->add(Cluster, K, V);
282 return add(Base, NewCluster);
283 }
284
285
addBinding(const MemRegion * R,BindingKey::Kind k,SVal V) const286 RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R,
287 BindingKey::Kind k,
288 SVal V) const {
289 return addBinding(BindingKey::Make(R, k), V);
290 }
291
lookup(BindingKey K) const292 const SVal *RegionBindingsRef::lookup(BindingKey K) const {
293 const ClusterBindings *Cluster = lookup(K.getBaseRegion());
294 if (!Cluster)
295 return nullptr;
296 return Cluster->lookup(K);
297 }
298
lookup(const MemRegion * R,BindingKey::Kind k) const299 const SVal *RegionBindingsRef::lookup(const MemRegion *R,
300 BindingKey::Kind k) const {
301 return lookup(BindingKey::Make(R, k));
302 }
303
removeBinding(BindingKey K)304 RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) {
305 const MemRegion *Base = K.getBaseRegion();
306 const ClusterBindings *Cluster = lookup(Base);
307 if (!Cluster)
308 return *this;
309
310 ClusterBindings NewCluster = CBFactory->remove(*Cluster, K);
311 if (NewCluster.isEmpty())
312 return remove(Base);
313 return add(Base, NewCluster);
314 }
315
removeBinding(const MemRegion * R,BindingKey::Kind k)316 RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R,
317 BindingKey::Kind k){
318 return removeBinding(BindingKey::Make(R, k));
319 }
320
321 //===----------------------------------------------------------------------===//
322 // Fine-grained control of RegionStoreManager.
323 //===----------------------------------------------------------------------===//
324
325 namespace {
326 struct minimal_features_tag {};
327 struct maximal_features_tag {};
328
329 class RegionStoreFeatures {
330 bool SupportsFields;
331 public:
RegionStoreFeatures(minimal_features_tag)332 RegionStoreFeatures(minimal_features_tag) :
333 SupportsFields(false) {}
334
RegionStoreFeatures(maximal_features_tag)335 RegionStoreFeatures(maximal_features_tag) :
336 SupportsFields(true) {}
337
enableFields(bool t)338 void enableFields(bool t) { SupportsFields = t; }
339
supportsFields() const340 bool supportsFields() const { return SupportsFields; }
341 };
342 }
343
344 //===----------------------------------------------------------------------===//
345 // Main RegionStore logic.
346 //===----------------------------------------------------------------------===//
347
348 namespace {
349 class InvalidateRegionsWorker;
350
351 class RegionStoreManager : public StoreManager {
352 public:
353 const RegionStoreFeatures Features;
354
355 RegionBindings::Factory RBFactory;
356 mutable ClusterBindings::Factory CBFactory;
357
358 typedef std::vector<SVal> SValListTy;
359 private:
360 typedef llvm::DenseMap<const LazyCompoundValData *,
361 SValListTy> LazyBindingsMapTy;
362 LazyBindingsMapTy LazyBindingsMap;
363
364 /// The largest number of fields a struct can have and still be
365 /// considered "small".
366 ///
367 /// This is currently used to decide whether or not it is worth "forcing" a
368 /// LazyCompoundVal on bind.
369 ///
370 /// This is controlled by 'region-store-small-struct-limit' option.
371 /// To disable all small-struct-dependent behavior, set the option to "0".
372 unsigned SmallStructLimit;
373
374 /// A helper used to populate the work list with the given set of
375 /// regions.
376 void populateWorkList(InvalidateRegionsWorker &W,
377 ArrayRef<SVal> Values,
378 InvalidatedRegions *TopLevelRegions);
379
380 public:
RegionStoreManager(ProgramStateManager & mgr,const RegionStoreFeatures & f)381 RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f)
382 : StoreManager(mgr), Features(f),
383 RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()),
384 SmallStructLimit(0) {
385 ExprEngine &Eng = StateMgr.getOwningEngine();
386 AnalyzerOptions &Options = Eng.getAnalysisManager().options;
387 SmallStructLimit = Options.RegionStoreSmallStructLimit;
388 }
389
390
391 /// setImplicitDefaultValue - Set the default binding for the provided
392 /// MemRegion to the value implicitly defined for compound literals when
393 /// the value is not specified.
394 RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B,
395 const MemRegion *R, QualType T);
396
397 /// ArrayToPointer - Emulates the "decay" of an array to a pointer
398 /// type. 'Array' represents the lvalue of the array being decayed
399 /// to a pointer, and the returned SVal represents the decayed
400 /// version of that lvalue (i.e., a pointer to the first element of
401 /// the array). This is called by ExprEngine when evaluating
402 /// casts from arrays to pointers.
403 SVal ArrayToPointer(Loc Array, QualType ElementTy) override;
404
405 /// Creates the Store that correctly represents memory contents before
406 /// the beginning of the analysis of the given top-level stack frame.
getInitialStore(const LocationContext * InitLoc)407 StoreRef getInitialStore(const LocationContext *InitLoc) override {
408 bool IsMainAnalysis = false;
409 if (const auto *FD = dyn_cast<FunctionDecl>(InitLoc->getDecl()))
410 IsMainAnalysis = FD->isMain() && !Ctx.getLangOpts().CPlusPlus;
411 return StoreRef(RegionBindingsRef(
412 RegionBindingsRef::ParentTy(RBFactory.getEmptyMap(), RBFactory),
413 CBFactory, IsMainAnalysis).asStore(), *this);
414 }
415
416 //===-------------------------------------------------------------------===//
417 // Binding values to regions.
418 //===-------------------------------------------------------------------===//
419 RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K,
420 const Expr *Ex,
421 unsigned Count,
422 const LocationContext *LCtx,
423 RegionBindingsRef B,
424 InvalidatedRegions *Invalidated);
425
426 StoreRef invalidateRegions(Store store,
427 ArrayRef<SVal> Values,
428 const Expr *E, unsigned Count,
429 const LocationContext *LCtx,
430 const CallEvent *Call,
431 InvalidatedSymbols &IS,
432 RegionAndSymbolInvalidationTraits &ITraits,
433 InvalidatedRegions *Invalidated,
434 InvalidatedRegions *InvalidatedTopLevel) override;
435
436 bool scanReachableSymbols(Store S, const MemRegion *R,
437 ScanReachableSymbols &Callbacks) override;
438
439 RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B,
440 const SubRegion *R);
441
442 public: // Part of public interface to class.
443
Bind(Store store,Loc LV,SVal V)444 StoreRef Bind(Store store, Loc LV, SVal V) override {
445 return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this);
446 }
447
448 RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V);
449
450 // BindDefaultInitial is only used to initialize a region with
451 // a default value.
BindDefaultInitial(Store store,const MemRegion * R,SVal V)452 StoreRef BindDefaultInitial(Store store, const MemRegion *R,
453 SVal V) override {
454 RegionBindingsRef B = getRegionBindings(store);
455 // Use other APIs when you have to wipe the region that was initialized
456 // earlier.
457 assert(!(B.getDefaultBinding(R) || B.getDirectBinding(R)) &&
458 "Double initialization!");
459 B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
460 return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
461 }
462
463 // BindDefaultZero is used for zeroing constructors that may accidentally
464 // overwrite existing bindings.
BindDefaultZero(Store store,const MemRegion * R)465 StoreRef BindDefaultZero(Store store, const MemRegion *R) override {
466 // FIXME: The offsets of empty bases can be tricky because of
467 // of the so called "empty base class optimization".
468 // If a base class has been optimized out
469 // we should not try to create a binding, otherwise we should.
470 // Unfortunately, at the moment ASTRecordLayout doesn't expose
471 // the actual sizes of the empty bases
472 // and trying to infer them from offsets/alignments
473 // seems to be error-prone and non-trivial because of the trailing padding.
474 // As a temporary mitigation we don't create bindings for empty bases.
475 if (const auto *BR = dyn_cast<CXXBaseObjectRegion>(R))
476 if (BR->getDecl()->isEmpty())
477 return StoreRef(store, *this);
478
479 RegionBindingsRef B = getRegionBindings(store);
480 SVal V = svalBuilder.makeZeroVal(Ctx.CharTy);
481 B = removeSubRegionBindings(B, cast<SubRegion>(R));
482 B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V);
483 return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this);
484 }
485
486 /// Attempt to extract the fields of \p LCV and bind them to the struct region
487 /// \p R.
488 ///
489 /// This path is used when it seems advantageous to "force" loading the values
490 /// within a LazyCompoundVal to bind memberwise to the struct region, rather
491 /// than using a Default binding at the base of the entire region. This is a
492 /// heuristic attempting to avoid building long chains of LazyCompoundVals.
493 ///
494 /// \returns The updated store bindings, or \c None if binding non-lazily
495 /// would be too expensive.
496 Optional<RegionBindingsRef> tryBindSmallStruct(RegionBindingsConstRef B,
497 const TypedValueRegion *R,
498 const RecordDecl *RD,
499 nonloc::LazyCompoundVal LCV);
500
501 /// BindStruct - Bind a compound value to a structure.
502 RegionBindingsRef bindStruct(RegionBindingsConstRef B,
503 const TypedValueRegion* R, SVal V);
504
505 /// BindVector - Bind a compound value to a vector.
506 RegionBindingsRef bindVector(RegionBindingsConstRef B,
507 const TypedValueRegion* R, SVal V);
508
509 RegionBindingsRef bindArray(RegionBindingsConstRef B,
510 const TypedValueRegion* R,
511 SVal V);
512
513 /// Clears out all bindings in the given region and assigns a new value
514 /// as a Default binding.
515 RegionBindingsRef bindAggregate(RegionBindingsConstRef B,
516 const TypedRegion *R,
517 SVal DefaultVal);
518
519 /// Create a new store with the specified binding removed.
520 /// \param ST the original store, that is the basis for the new store.
521 /// \param L the location whose binding should be removed.
522 StoreRef killBinding(Store ST, Loc L) override;
523
incrementReferenceCount(Store store)524 void incrementReferenceCount(Store store) override {
525 getRegionBindings(store).manualRetain();
526 }
527
528 /// If the StoreManager supports it, decrement the reference count of
529 /// the specified Store object. If the reference count hits 0, the memory
530 /// associated with the object is recycled.
decrementReferenceCount(Store store)531 void decrementReferenceCount(Store store) override {
532 getRegionBindings(store).manualRelease();
533 }
534
535 bool includedInBindings(Store store, const MemRegion *region) const override;
536
537 /// Return the value bound to specified location in a given state.
538 ///
539 /// The high level logic for this method is this:
540 /// getBinding (L)
541 /// if L has binding
542 /// return L's binding
543 /// else if L is in killset
544 /// return unknown
545 /// else
546 /// if L is on stack or heap
547 /// return undefined
548 /// else
549 /// return symbolic
getBinding(Store S,Loc L,QualType T)550 SVal getBinding(Store S, Loc L, QualType T) override {
551 return getBinding(getRegionBindings(S), L, T);
552 }
553
getDefaultBinding(Store S,const MemRegion * R)554 Optional<SVal> getDefaultBinding(Store S, const MemRegion *R) override {
555 RegionBindingsRef B = getRegionBindings(S);
556 // Default bindings are always applied over a base region so look up the
557 // base region's default binding, otherwise the lookup will fail when R
558 // is at an offset from R->getBaseRegion().
559 return B.getDefaultBinding(R->getBaseRegion());
560 }
561
562 SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType());
563
564 SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R);
565
566 SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R);
567
568 SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R);
569
570 SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R);
571
572 SVal getBindingForLazySymbol(const TypedValueRegion *R);
573
574 SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
575 const TypedValueRegion *R,
576 QualType Ty);
577
578 SVal getLazyBinding(const SubRegion *LazyBindingRegion,
579 RegionBindingsRef LazyBinding);
580
581 /// Get bindings for the values in a struct and return a CompoundVal, used
582 /// when doing struct copy:
583 /// struct s x, y;
584 /// x = y;
585 /// y's value is retrieved by this method.
586 SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R);
587 SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R);
588 NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R);
589
590 /// Used to lazily generate derived symbols for bindings that are defined
591 /// implicitly by default bindings in a super region.
592 ///
593 /// Note that callers may need to specially handle LazyCompoundVals, which
594 /// are returned as is in case the caller needs to treat them differently.
595 Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
596 const MemRegion *superR,
597 const TypedValueRegion *R,
598 QualType Ty);
599
600 /// Get the state and region whose binding this region \p R corresponds to.
601 ///
602 /// If there is no lazy binding for \p R, the returned value will have a null
603 /// \c second. Note that a null pointer can represents a valid Store.
604 std::pair<Store, const SubRegion *>
605 findLazyBinding(RegionBindingsConstRef B, const SubRegion *R,
606 const SubRegion *originalRegion);
607
608 /// Returns the cached set of interesting SVals contained within a lazy
609 /// binding.
610 ///
611 /// The precise value of "interesting" is determined for the purposes of
612 /// RegionStore's internal analysis. It must always contain all regions and
613 /// symbols, but may omit constants and other kinds of SVal.
614 const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV);
615
616 //===------------------------------------------------------------------===//
617 // State pruning.
618 //===------------------------------------------------------------------===//
619
620 /// removeDeadBindings - Scans the RegionStore of 'state' for dead values.
621 /// It returns a new Store with these values removed.
622 StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
623 SymbolReaper& SymReaper) override;
624
625 //===------------------------------------------------------------------===//
626 // Utility methods.
627 //===------------------------------------------------------------------===//
628
getRegionBindings(Store store) const629 RegionBindingsRef getRegionBindings(Store store) const {
630 llvm::PointerIntPair<Store, 1, bool> Ptr;
631 Ptr.setFromOpaqueValue(const_cast<void *>(store));
632 return RegionBindingsRef(
633 CBFactory,
634 static_cast<const RegionBindings::TreeTy *>(Ptr.getPointer()),
635 RBFactory.getTreeFactory(),
636 Ptr.getInt());
637 }
638
639 void printJson(raw_ostream &Out, Store S, const char *NL = "\n",
640 unsigned int Space = 0, bool IsDot = false) const override;
641
iterBindings(Store store,BindingsHandler & f)642 void iterBindings(Store store, BindingsHandler& f) override {
643 RegionBindingsRef B = getRegionBindings(store);
644 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
645 const ClusterBindings &Cluster = I.getData();
646 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
647 CI != CE; ++CI) {
648 const BindingKey &K = CI.getKey();
649 if (!K.isDirect())
650 continue;
651 if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) {
652 // FIXME: Possibly incorporate the offset?
653 if (!f.HandleBinding(*this, store, R, CI.getData()))
654 return;
655 }
656 }
657 }
658 }
659 };
660
661 } // end anonymous namespace
662
663 //===----------------------------------------------------------------------===//
664 // RegionStore creation.
665 //===----------------------------------------------------------------------===//
666
667 std::unique_ptr<StoreManager>
CreateRegionStoreManager(ProgramStateManager & StMgr)668 ento::CreateRegionStoreManager(ProgramStateManager &StMgr) {
669 RegionStoreFeatures F = maximal_features_tag();
670 return std::make_unique<RegionStoreManager>(StMgr, F);
671 }
672
673 std::unique_ptr<StoreManager>
CreateFieldsOnlyRegionStoreManager(ProgramStateManager & StMgr)674 ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) {
675 RegionStoreFeatures F = minimal_features_tag();
676 F.enableFields(true);
677 return std::make_unique<RegionStoreManager>(StMgr, F);
678 }
679
680
681 //===----------------------------------------------------------------------===//
682 // Region Cluster analysis.
683 //===----------------------------------------------------------------------===//
684
685 namespace {
686 /// Used to determine which global regions are automatically included in the
687 /// initial worklist of a ClusterAnalysis.
688 enum GlobalsFilterKind {
689 /// Don't include any global regions.
690 GFK_None,
691 /// Only include system globals.
692 GFK_SystemOnly,
693 /// Include all global regions.
694 GFK_All
695 };
696
697 template <typename DERIVED>
698 class ClusterAnalysis {
699 protected:
700 typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap;
701 typedef const MemRegion * WorkListElement;
702 typedef SmallVector<WorkListElement, 10> WorkList;
703
704 llvm::SmallPtrSet<const ClusterBindings *, 16> Visited;
705
706 WorkList WL;
707
708 RegionStoreManager &RM;
709 ASTContext &Ctx;
710 SValBuilder &svalBuilder;
711
712 RegionBindingsRef B;
713
714
715 protected:
getCluster(const MemRegion * R)716 const ClusterBindings *getCluster(const MemRegion *R) {
717 return B.lookup(R);
718 }
719
720 /// Returns true if all clusters in the given memspace should be initially
721 /// included in the cluster analysis. Subclasses may provide their
722 /// own implementation.
includeEntireMemorySpace(const MemRegion * Base)723 bool includeEntireMemorySpace(const MemRegion *Base) {
724 return false;
725 }
726
727 public:
ClusterAnalysis(RegionStoreManager & rm,ProgramStateManager & StateMgr,RegionBindingsRef b)728 ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr,
729 RegionBindingsRef b)
730 : RM(rm), Ctx(StateMgr.getContext()),
731 svalBuilder(StateMgr.getSValBuilder()), B(std::move(b)) {}
732
getRegionBindings() const733 RegionBindingsRef getRegionBindings() const { return B; }
734
isVisited(const MemRegion * R)735 bool isVisited(const MemRegion *R) {
736 return Visited.count(getCluster(R));
737 }
738
GenerateClusters()739 void GenerateClusters() {
740 // Scan the entire set of bindings and record the region clusters.
741 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end();
742 RI != RE; ++RI){
743 const MemRegion *Base = RI.getKey();
744
745 const ClusterBindings &Cluster = RI.getData();
746 assert(!Cluster.isEmpty() && "Empty clusters should be removed");
747 static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster);
748
749 // If the base's memspace should be entirely invalidated, add the cluster
750 // to the workspace up front.
751 if (static_cast<DERIVED*>(this)->includeEntireMemorySpace(Base))
752 AddToWorkList(WorkListElement(Base), &Cluster);
753 }
754 }
755
AddToWorkList(WorkListElement E,const ClusterBindings * C)756 bool AddToWorkList(WorkListElement E, const ClusterBindings *C) {
757 if (C && !Visited.insert(C).second)
758 return false;
759 WL.push_back(E);
760 return true;
761 }
762
AddToWorkList(const MemRegion * R)763 bool AddToWorkList(const MemRegion *R) {
764 return static_cast<DERIVED*>(this)->AddToWorkList(R);
765 }
766
RunWorkList()767 void RunWorkList() {
768 while (!WL.empty()) {
769 WorkListElement E = WL.pop_back_val();
770 const MemRegion *BaseR = E;
771
772 static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR));
773 }
774 }
775
VisitAddedToCluster(const MemRegion * baseR,const ClusterBindings & C)776 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {}
VisitCluster(const MemRegion * baseR,const ClusterBindings * C)777 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {}
778
VisitCluster(const MemRegion * BaseR,const ClusterBindings * C,bool Flag)779 void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C,
780 bool Flag) {
781 static_cast<DERIVED*>(this)->VisitCluster(BaseR, C);
782 }
783 };
784 }
785
786 //===----------------------------------------------------------------------===//
787 // Binding invalidation.
788 //===----------------------------------------------------------------------===//
789
scanReachableSymbols(Store S,const MemRegion * R,ScanReachableSymbols & Callbacks)790 bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R,
791 ScanReachableSymbols &Callbacks) {
792 assert(R == R->getBaseRegion() && "Should only be called for base regions");
793 RegionBindingsRef B = getRegionBindings(S);
794 const ClusterBindings *Cluster = B.lookup(R);
795
796 if (!Cluster)
797 return true;
798
799 for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end();
800 RI != RE; ++RI) {
801 if (!Callbacks.scan(RI.getData()))
802 return false;
803 }
804
805 return true;
806 }
807
isUnionField(const FieldRegion * FR)808 static inline bool isUnionField(const FieldRegion *FR) {
809 return FR->getDecl()->getParent()->isUnion();
810 }
811
812 typedef SmallVector<const FieldDecl *, 8> FieldVector;
813
getSymbolicOffsetFields(BindingKey K,FieldVector & Fields)814 static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) {
815 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
816
817 const MemRegion *Base = K.getConcreteOffsetRegion();
818 const MemRegion *R = K.getRegion();
819
820 while (R != Base) {
821 if (const FieldRegion *FR = dyn_cast<FieldRegion>(R))
822 if (!isUnionField(FR))
823 Fields.push_back(FR->getDecl());
824
825 R = cast<SubRegion>(R)->getSuperRegion();
826 }
827 }
828
isCompatibleWithFields(BindingKey K,const FieldVector & Fields)829 static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) {
830 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
831
832 if (Fields.empty())
833 return true;
834
835 FieldVector FieldsInBindingKey;
836 getSymbolicOffsetFields(K, FieldsInBindingKey);
837
838 ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size();
839 if (Delta >= 0)
840 return std::equal(FieldsInBindingKey.begin() + Delta,
841 FieldsInBindingKey.end(),
842 Fields.begin());
843 else
844 return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(),
845 Fields.begin() - Delta);
846 }
847
848 /// Collects all bindings in \p Cluster that may refer to bindings within
849 /// \p Top.
850 ///
851 /// Each binding is a pair whose \c first is the key (a BindingKey) and whose
852 /// \c second is the value (an SVal).
853 ///
854 /// The \p IncludeAllDefaultBindings parameter specifies whether to include
855 /// default bindings that may extend beyond \p Top itself, e.g. if \p Top is
856 /// an aggregate within a larger aggregate with a default binding.
857 static void
collectSubRegionBindings(SmallVectorImpl<BindingPair> & Bindings,SValBuilder & SVB,const ClusterBindings & Cluster,const SubRegion * Top,BindingKey TopKey,bool IncludeAllDefaultBindings)858 collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings,
859 SValBuilder &SVB, const ClusterBindings &Cluster,
860 const SubRegion *Top, BindingKey TopKey,
861 bool IncludeAllDefaultBindings) {
862 FieldVector FieldsInSymbolicSubregions;
863 if (TopKey.hasSymbolicOffset()) {
864 getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions);
865 Top = TopKey.getConcreteOffsetRegion();
866 TopKey = BindingKey::Make(Top, BindingKey::Default);
867 }
868
869 // Find the length (in bits) of the region being invalidated.
870 uint64_t Length = UINT64_MAX;
871 SVal Extent = Top->getMemRegionManager().getStaticSize(Top, SVB);
872 if (Optional<nonloc::ConcreteInt> ExtentCI =
873 Extent.getAs<nonloc::ConcreteInt>()) {
874 const llvm::APSInt &ExtentInt = ExtentCI->getValue();
875 assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned());
876 // Extents are in bytes but region offsets are in bits. Be careful!
877 Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth();
878 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) {
879 if (FR->getDecl()->isBitField())
880 Length = FR->getDecl()->getBitWidthValue(SVB.getContext());
881 }
882
883 for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end();
884 I != E; ++I) {
885 BindingKey NextKey = I.getKey();
886 if (NextKey.getRegion() == TopKey.getRegion()) {
887 // FIXME: This doesn't catch the case where we're really invalidating a
888 // region with a symbolic offset. Example:
889 // R: points[i].y
890 // Next: points[0].x
891
892 if (NextKey.getOffset() > TopKey.getOffset() &&
893 NextKey.getOffset() - TopKey.getOffset() < Length) {
894 // Case 1: The next binding is inside the region we're invalidating.
895 // Include it.
896 Bindings.push_back(*I);
897
898 } else if (NextKey.getOffset() == TopKey.getOffset()) {
899 // Case 2: The next binding is at the same offset as the region we're
900 // invalidating. In this case, we need to leave default bindings alone,
901 // since they may be providing a default value for a regions beyond what
902 // we're invalidating.
903 // FIXME: This is probably incorrect; consider invalidating an outer
904 // struct whose first field is bound to a LazyCompoundVal.
905 if (IncludeAllDefaultBindings || NextKey.isDirect())
906 Bindings.push_back(*I);
907 }
908
909 } else if (NextKey.hasSymbolicOffset()) {
910 const MemRegion *Base = NextKey.getConcreteOffsetRegion();
911 if (Top->isSubRegionOf(Base) && Top != Base) {
912 // Case 3: The next key is symbolic and we just changed something within
913 // its concrete region. We don't know if the binding is still valid, so
914 // we'll be conservative and include it.
915 if (IncludeAllDefaultBindings || NextKey.isDirect())
916 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
917 Bindings.push_back(*I);
918 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) {
919 // Case 4: The next key is symbolic, but we changed a known
920 // super-region. In this case the binding is certainly included.
921 if (BaseSR->isSubRegionOf(Top))
922 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions))
923 Bindings.push_back(*I);
924 }
925 }
926 }
927 }
928
929 static void
collectSubRegionBindings(SmallVectorImpl<BindingPair> & Bindings,SValBuilder & SVB,const ClusterBindings & Cluster,const SubRegion * Top,bool IncludeAllDefaultBindings)930 collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings,
931 SValBuilder &SVB, const ClusterBindings &Cluster,
932 const SubRegion *Top, bool IncludeAllDefaultBindings) {
933 collectSubRegionBindings(Bindings, SVB, Cluster, Top,
934 BindingKey::Make(Top, BindingKey::Default),
935 IncludeAllDefaultBindings);
936 }
937
938 RegionBindingsRef
removeSubRegionBindings(RegionBindingsConstRef B,const SubRegion * Top)939 RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B,
940 const SubRegion *Top) {
941 BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default);
942 const MemRegion *ClusterHead = TopKey.getBaseRegion();
943
944 if (Top == ClusterHead) {
945 // We can remove an entire cluster's bindings all in one go.
946 return B.remove(Top);
947 }
948
949 const ClusterBindings *Cluster = B.lookup(ClusterHead);
950 if (!Cluster) {
951 // If we're invalidating a region with a symbolic offset, we need to make
952 // sure we don't treat the base region as uninitialized anymore.
953 if (TopKey.hasSymbolicOffset()) {
954 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
955 return B.addBinding(Concrete, BindingKey::Default, UnknownVal());
956 }
957 return B;
958 }
959
960 SmallVector<BindingPair, 32> Bindings;
961 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey,
962 /*IncludeAllDefaultBindings=*/false);
963
964 ClusterBindingsRef Result(*Cluster, CBFactory);
965 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
966 E = Bindings.end();
967 I != E; ++I)
968 Result = Result.remove(I->first);
969
970 // If we're invalidating a region with a symbolic offset, we need to make sure
971 // we don't treat the base region as uninitialized anymore.
972 // FIXME: This isn't very precise; see the example in
973 // collectSubRegionBindings.
974 if (TopKey.hasSymbolicOffset()) {
975 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
976 Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default),
977 UnknownVal());
978 }
979
980 if (Result.isEmpty())
981 return B.remove(ClusterHead);
982 return B.add(ClusterHead, Result.asImmutableMap());
983 }
984
985 namespace {
986 class InvalidateRegionsWorker : public ClusterAnalysis<InvalidateRegionsWorker>
987 {
988 const Expr *Ex;
989 unsigned Count;
990 const LocationContext *LCtx;
991 InvalidatedSymbols &IS;
992 RegionAndSymbolInvalidationTraits &ITraits;
993 StoreManager::InvalidatedRegions *Regions;
994 GlobalsFilterKind GlobalsFilter;
995 public:
InvalidateRegionsWorker(RegionStoreManager & rm,ProgramStateManager & stateMgr,RegionBindingsRef b,const Expr * ex,unsigned count,const LocationContext * lctx,InvalidatedSymbols & is,RegionAndSymbolInvalidationTraits & ITraitsIn,StoreManager::InvalidatedRegions * r,GlobalsFilterKind GFK)996 InvalidateRegionsWorker(RegionStoreManager &rm,
997 ProgramStateManager &stateMgr,
998 RegionBindingsRef b,
999 const Expr *ex, unsigned count,
1000 const LocationContext *lctx,
1001 InvalidatedSymbols &is,
1002 RegionAndSymbolInvalidationTraits &ITraitsIn,
1003 StoreManager::InvalidatedRegions *r,
1004 GlobalsFilterKind GFK)
1005 : ClusterAnalysis<InvalidateRegionsWorker>(rm, stateMgr, b),
1006 Ex(ex), Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r),
1007 GlobalsFilter(GFK) {}
1008
1009 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
1010 void VisitBinding(SVal V);
1011
1012 using ClusterAnalysis::AddToWorkList;
1013
1014 bool AddToWorkList(const MemRegion *R);
1015
1016 /// Returns true if all clusters in the memory space for \p Base should be
1017 /// be invalidated.
1018 bool includeEntireMemorySpace(const MemRegion *Base);
1019
1020 /// Returns true if the memory space of the given region is one of the global
1021 /// regions specially included at the start of invalidation.
1022 bool isInitiallyIncludedGlobalRegion(const MemRegion *R);
1023 };
1024 }
1025
AddToWorkList(const MemRegion * R)1026 bool InvalidateRegionsWorker::AddToWorkList(const MemRegion *R) {
1027 bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1028 R, RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
1029 const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion();
1030 return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
1031 }
1032
VisitBinding(SVal V)1033 void InvalidateRegionsWorker::VisitBinding(SVal V) {
1034 // A symbol? Mark it touched by the invalidation.
1035 if (SymbolRef Sym = V.getAsSymbol())
1036 IS.insert(Sym);
1037
1038 if (const MemRegion *R = V.getAsRegion()) {
1039 AddToWorkList(R);
1040 return;
1041 }
1042
1043 // Is it a LazyCompoundVal? All references get invalidated as well.
1044 if (Optional<nonloc::LazyCompoundVal> LCS =
1045 V.getAs<nonloc::LazyCompoundVal>()) {
1046
1047 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
1048
1049 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
1050 E = Vals.end();
1051 I != E; ++I)
1052 VisitBinding(*I);
1053
1054 return;
1055 }
1056 }
1057
VisitCluster(const MemRegion * baseR,const ClusterBindings * C)1058 void InvalidateRegionsWorker::VisitCluster(const MemRegion *baseR,
1059 const ClusterBindings *C) {
1060
1061 bool PreserveRegionsContents =
1062 ITraits.hasTrait(baseR,
1063 RegionAndSymbolInvalidationTraits::TK_PreserveContents);
1064
1065 if (C) {
1066 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I)
1067 VisitBinding(I.getData());
1068
1069 // Invalidate regions contents.
1070 if (!PreserveRegionsContents)
1071 B = B.remove(baseR);
1072 }
1073
1074 if (const auto *TO = dyn_cast<TypedValueRegion>(baseR)) {
1075 if (const auto *RD = TO->getValueType()->getAsCXXRecordDecl()) {
1076
1077 // Lambdas can affect all static local variables without explicitly
1078 // capturing those.
1079 // We invalidate all static locals referenced inside the lambda body.
1080 if (RD->isLambda() && RD->getLambdaCallOperator()->getBody()) {
1081 using namespace ast_matchers;
1082
1083 const char *DeclBind = "DeclBind";
1084 StatementMatcher RefToStatic = stmt(hasDescendant(declRefExpr(
1085 to(varDecl(hasStaticStorageDuration()).bind(DeclBind)))));
1086 auto Matches =
1087 match(RefToStatic, *RD->getLambdaCallOperator()->getBody(),
1088 RD->getASTContext());
1089
1090 for (BoundNodes &Match : Matches) {
1091 auto *VD = Match.getNodeAs<VarDecl>(DeclBind);
1092 const VarRegion *ToInvalidate =
1093 RM.getRegionManager().getVarRegion(VD, LCtx);
1094 AddToWorkList(ToInvalidate);
1095 }
1096 }
1097 }
1098 }
1099
1100 // BlockDataRegion? If so, invalidate captured variables that are passed
1101 // by reference.
1102 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) {
1103 for (BlockDataRegion::referenced_vars_iterator
1104 BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ;
1105 BI != BE; ++BI) {
1106 const VarRegion *VR = BI.getCapturedRegion();
1107 const VarDecl *VD = VR->getDecl();
1108 if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage()) {
1109 AddToWorkList(VR);
1110 }
1111 else if (Loc::isLocType(VR->getValueType())) {
1112 // Map the current bindings to a Store to retrieve the value
1113 // of the binding. If that binding itself is a region, we should
1114 // invalidate that region. This is because a block may capture
1115 // a pointer value, but the thing pointed by that pointer may
1116 // get invalidated.
1117 SVal V = RM.getBinding(B, loc::MemRegionVal(VR));
1118 if (Optional<Loc> L = V.getAs<Loc>()) {
1119 if (const MemRegion *LR = L->getAsRegion())
1120 AddToWorkList(LR);
1121 }
1122 }
1123 }
1124 return;
1125 }
1126
1127 // Symbolic region?
1128 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR))
1129 IS.insert(SR->getSymbol());
1130
1131 // Nothing else should be done in the case when we preserve regions context.
1132 if (PreserveRegionsContents)
1133 return;
1134
1135 // Otherwise, we have a normal data region. Record that we touched the region.
1136 if (Regions)
1137 Regions->push_back(baseR);
1138
1139 if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) {
1140 // Invalidate the region by setting its default value to
1141 // conjured symbol. The type of the symbol is irrelevant.
1142 DefinedOrUnknownSVal V =
1143 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count);
1144 B = B.addBinding(baseR, BindingKey::Default, V);
1145 return;
1146 }
1147
1148 if (!baseR->isBoundable())
1149 return;
1150
1151 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR);
1152 QualType T = TR->getValueType();
1153
1154 if (isInitiallyIncludedGlobalRegion(baseR)) {
1155 // If the region is a global and we are invalidating all globals,
1156 // erasing the entry is good enough. This causes all globals to be lazily
1157 // symbolicated from the same base symbol.
1158 return;
1159 }
1160
1161 if (T->isRecordType()) {
1162 // Invalidate the region by setting its default value to
1163 // conjured symbol. The type of the symbol is irrelevant.
1164 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1165 Ctx.IntTy, Count);
1166 B = B.addBinding(baseR, BindingKey::Default, V);
1167 return;
1168 }
1169
1170 if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
1171 bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1172 baseR,
1173 RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
1174
1175 if (doNotInvalidateSuperRegion) {
1176 // We are not doing blank invalidation of the whole array region so we
1177 // have to manually invalidate each elements.
1178 Optional<uint64_t> NumElements;
1179
1180 // Compute lower and upper offsets for region within array.
1181 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT))
1182 NumElements = CAT->getSize().getZExtValue();
1183 if (!NumElements) // We are not dealing with a constant size array
1184 goto conjure_default;
1185 QualType ElementTy = AT->getElementType();
1186 uint64_t ElemSize = Ctx.getTypeSize(ElementTy);
1187 const RegionOffset &RO = baseR->getAsOffset();
1188 const MemRegion *SuperR = baseR->getBaseRegion();
1189 if (RO.hasSymbolicOffset()) {
1190 // If base region has a symbolic offset,
1191 // we revert to invalidating the super region.
1192 if (SuperR)
1193 AddToWorkList(SuperR);
1194 goto conjure_default;
1195 }
1196
1197 uint64_t LowerOffset = RO.getOffset();
1198 uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize;
1199 bool UpperOverflow = UpperOffset < LowerOffset;
1200
1201 // Invalidate regions which are within array boundaries,
1202 // or have a symbolic offset.
1203 if (!SuperR)
1204 goto conjure_default;
1205
1206 const ClusterBindings *C = B.lookup(SuperR);
1207 if (!C)
1208 goto conjure_default;
1209
1210 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E;
1211 ++I) {
1212 const BindingKey &BK = I.getKey();
1213 Optional<uint64_t> ROffset =
1214 BK.hasSymbolicOffset() ? Optional<uint64_t>() : BK.getOffset();
1215
1216 // Check offset is not symbolic and within array's boundaries.
1217 // Handles arrays of 0 elements and of 0-sized elements as well.
1218 if (!ROffset ||
1219 ((*ROffset >= LowerOffset && *ROffset < UpperOffset) ||
1220 (UpperOverflow &&
1221 (*ROffset >= LowerOffset || *ROffset < UpperOffset)) ||
1222 (LowerOffset == UpperOffset && *ROffset == LowerOffset))) {
1223 B = B.removeBinding(I.getKey());
1224 // Bound symbolic regions need to be invalidated for dead symbol
1225 // detection.
1226 SVal V = I.getData();
1227 const MemRegion *R = V.getAsRegion();
1228 if (R && isa<SymbolicRegion>(R))
1229 VisitBinding(V);
1230 }
1231 }
1232 }
1233 conjure_default:
1234 // Set the default value of the array to conjured symbol.
1235 DefinedOrUnknownSVal V =
1236 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1237 AT->getElementType(), Count);
1238 B = B.addBinding(baseR, BindingKey::Default, V);
1239 return;
1240 }
1241
1242 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx,
1243 T,Count);
1244 assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
1245 B = B.addBinding(baseR, BindingKey::Direct, V);
1246 }
1247
isInitiallyIncludedGlobalRegion(const MemRegion * R)1248 bool InvalidateRegionsWorker::isInitiallyIncludedGlobalRegion(
1249 const MemRegion *R) {
1250 switch (GlobalsFilter) {
1251 case GFK_None:
1252 return false;
1253 case GFK_SystemOnly:
1254 return isa<GlobalSystemSpaceRegion>(R->getMemorySpace());
1255 case GFK_All:
1256 return isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace());
1257 }
1258
1259 llvm_unreachable("unknown globals filter");
1260 }
1261
includeEntireMemorySpace(const MemRegion * Base)1262 bool InvalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) {
1263 if (isInitiallyIncludedGlobalRegion(Base))
1264 return true;
1265
1266 const MemSpaceRegion *MemSpace = Base->getMemorySpace();
1267 return ITraits.hasTrait(MemSpace,
1268 RegionAndSymbolInvalidationTraits::TK_EntireMemSpace);
1269 }
1270
1271 RegionBindingsRef
invalidateGlobalRegion(MemRegion::Kind K,const Expr * Ex,unsigned Count,const LocationContext * LCtx,RegionBindingsRef B,InvalidatedRegions * Invalidated)1272 RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K,
1273 const Expr *Ex,
1274 unsigned Count,
1275 const LocationContext *LCtx,
1276 RegionBindingsRef B,
1277 InvalidatedRegions *Invalidated) {
1278 // Bind the globals memory space to a new symbol that we will use to derive
1279 // the bindings for all globals.
1280 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K);
1281 SVal V = svalBuilder.conjureSymbolVal(/* symbolTag = */ (const void*) GS, Ex, LCtx,
1282 /* type does not matter */ Ctx.IntTy,
1283 Count);
1284
1285 B = B.removeBinding(GS)
1286 .addBinding(BindingKey::Make(GS, BindingKey::Default), V);
1287
1288 // Even if there are no bindings in the global scope, we still need to
1289 // record that we touched it.
1290 if (Invalidated)
1291 Invalidated->push_back(GS);
1292
1293 return B;
1294 }
1295
populateWorkList(InvalidateRegionsWorker & W,ArrayRef<SVal> Values,InvalidatedRegions * TopLevelRegions)1296 void RegionStoreManager::populateWorkList(InvalidateRegionsWorker &W,
1297 ArrayRef<SVal> Values,
1298 InvalidatedRegions *TopLevelRegions) {
1299 for (ArrayRef<SVal>::iterator I = Values.begin(),
1300 E = Values.end(); I != E; ++I) {
1301 SVal V = *I;
1302 if (Optional<nonloc::LazyCompoundVal> LCS =
1303 V.getAs<nonloc::LazyCompoundVal>()) {
1304
1305 const SValListTy &Vals = getInterestingValues(*LCS);
1306
1307 for (SValListTy::const_iterator I = Vals.begin(),
1308 E = Vals.end(); I != E; ++I) {
1309 // Note: the last argument is false here because these are
1310 // non-top-level regions.
1311 if (const MemRegion *R = (*I).getAsRegion())
1312 W.AddToWorkList(R);
1313 }
1314 continue;
1315 }
1316
1317 if (const MemRegion *R = V.getAsRegion()) {
1318 if (TopLevelRegions)
1319 TopLevelRegions->push_back(R);
1320 W.AddToWorkList(R);
1321 continue;
1322 }
1323 }
1324 }
1325
1326 StoreRef
invalidateRegions(Store store,ArrayRef<SVal> Values,const Expr * Ex,unsigned Count,const LocationContext * LCtx,const CallEvent * Call,InvalidatedSymbols & IS,RegionAndSymbolInvalidationTraits & ITraits,InvalidatedRegions * TopLevelRegions,InvalidatedRegions * Invalidated)1327 RegionStoreManager::invalidateRegions(Store store,
1328 ArrayRef<SVal> Values,
1329 const Expr *Ex, unsigned Count,
1330 const LocationContext *LCtx,
1331 const CallEvent *Call,
1332 InvalidatedSymbols &IS,
1333 RegionAndSymbolInvalidationTraits &ITraits,
1334 InvalidatedRegions *TopLevelRegions,
1335 InvalidatedRegions *Invalidated) {
1336 GlobalsFilterKind GlobalsFilter;
1337 if (Call) {
1338 if (Call->isInSystemHeader())
1339 GlobalsFilter = GFK_SystemOnly;
1340 else
1341 GlobalsFilter = GFK_All;
1342 } else {
1343 GlobalsFilter = GFK_None;
1344 }
1345
1346 RegionBindingsRef B = getRegionBindings(store);
1347 InvalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, ITraits,
1348 Invalidated, GlobalsFilter);
1349
1350 // Scan the bindings and generate the clusters.
1351 W.GenerateClusters();
1352
1353 // Add the regions to the worklist.
1354 populateWorkList(W, Values, TopLevelRegions);
1355
1356 W.RunWorkList();
1357
1358 // Return the new bindings.
1359 B = W.getRegionBindings();
1360
1361 // For calls, determine which global regions should be invalidated and
1362 // invalidate them. (Note that function-static and immutable globals are never
1363 // invalidated by this.)
1364 // TODO: This could possibly be more precise with modules.
1365 switch (GlobalsFilter) {
1366 case GFK_All:
1367 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind,
1368 Ex, Count, LCtx, B, Invalidated);
1369 LLVM_FALLTHROUGH;
1370 case GFK_SystemOnly:
1371 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind,
1372 Ex, Count, LCtx, B, Invalidated);
1373 LLVM_FALLTHROUGH;
1374 case GFK_None:
1375 break;
1376 }
1377
1378 return StoreRef(B.asStore(), *this);
1379 }
1380
1381 //===----------------------------------------------------------------------===//
1382 // Location and region casting.
1383 //===----------------------------------------------------------------------===//
1384
1385 /// ArrayToPointer - Emulates the "decay" of an array to a pointer
1386 /// type. 'Array' represents the lvalue of the array being decayed
1387 /// to a pointer, and the returned SVal represents the decayed
1388 /// version of that lvalue (i.e., a pointer to the first element of
1389 /// the array). This is called by ExprEngine when evaluating casts
1390 /// from arrays to pointers.
ArrayToPointer(Loc Array,QualType T)1391 SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) {
1392 if (Array.getAs<loc::ConcreteInt>())
1393 return Array;
1394
1395 if (!Array.getAs<loc::MemRegionVal>())
1396 return UnknownVal();
1397
1398 const SubRegion *R =
1399 cast<SubRegion>(Array.castAs<loc::MemRegionVal>().getRegion());
1400 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
1401 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, R, Ctx));
1402 }
1403
1404 //===----------------------------------------------------------------------===//
1405 // Loading values from regions.
1406 //===----------------------------------------------------------------------===//
1407
getBinding(RegionBindingsConstRef B,Loc L,QualType T)1408 SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) {
1409 assert(!L.getAs<UnknownVal>() && "location unknown");
1410 assert(!L.getAs<UndefinedVal>() && "location undefined");
1411
1412 // For access to concrete addresses, return UnknownVal. Checks
1413 // for null dereferences (and similar errors) are done by checkers, not
1414 // the Store.
1415 // FIXME: We can consider lazily symbolicating such memory, but we really
1416 // should defer this when we can reason easily about symbolicating arrays
1417 // of bytes.
1418 if (L.getAs<loc::ConcreteInt>()) {
1419 return UnknownVal();
1420 }
1421 if (!L.getAs<loc::MemRegionVal>()) {
1422 return UnknownVal();
1423 }
1424
1425 const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion();
1426
1427 if (isa<BlockDataRegion>(MR)) {
1428 return UnknownVal();
1429 }
1430
1431 if (!isa<TypedValueRegion>(MR)) {
1432 if (T.isNull()) {
1433 if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
1434 T = TR->getLocationType()->getPointeeType();
1435 else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1436 T = SR->getSymbol()->getType()->getPointeeType();
1437 }
1438 assert(!T.isNull() && "Unable to auto-detect binding type!");
1439 assert(!T->isVoidType() && "Attempting to dereference a void pointer!");
1440 MR = GetElementZeroRegion(cast<SubRegion>(MR), T);
1441 } else {
1442 T = cast<TypedValueRegion>(MR)->getValueType();
1443 }
1444
1445 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
1446 // instead of 'Loc', and have the other Loc cases handled at a higher level.
1447 const TypedValueRegion *R = cast<TypedValueRegion>(MR);
1448 QualType RTy = R->getValueType();
1449
1450 // FIXME: we do not yet model the parts of a complex type, so treat the
1451 // whole thing as "unknown".
1452 if (RTy->isAnyComplexType())
1453 return UnknownVal();
1454
1455 // FIXME: We should eventually handle funny addressing. e.g.:
1456 //
1457 // int x = ...;
1458 // int *p = &x;
1459 // char *q = (char*) p;
1460 // char c = *q; // returns the first byte of 'x'.
1461 //
1462 // Such funny addressing will occur due to layering of regions.
1463 if (RTy->isStructureOrClassType())
1464 return getBindingForStruct(B, R);
1465
1466 // FIXME: Handle unions.
1467 if (RTy->isUnionType())
1468 return createLazyBinding(B, R);
1469
1470 if (RTy->isArrayType()) {
1471 if (RTy->isConstantArrayType())
1472 return getBindingForArray(B, R);
1473 else
1474 return UnknownVal();
1475 }
1476
1477 // FIXME: handle Vector types.
1478 if (RTy->isVectorType())
1479 return UnknownVal();
1480
1481 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R))
1482 return CastRetrievedVal(getBindingForField(B, FR), FR, T);
1483
1484 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
1485 // FIXME: Here we actually perform an implicit conversion from the loaded
1486 // value to the element type. Eventually we want to compose these values
1487 // more intelligently. For example, an 'element' can encompass multiple
1488 // bound regions (e.g., several bound bytes), or could be a subset of
1489 // a larger value.
1490 return CastRetrievedVal(getBindingForElement(B, ER), ER, T);
1491 }
1492
1493 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) {
1494 // FIXME: Here we actually perform an implicit conversion from the loaded
1495 // value to the ivar type. What we should model is stores to ivars
1496 // that blow past the extent of the ivar. If the address of the ivar is
1497 // reinterpretted, it is possible we stored a different value that could
1498 // fit within the ivar. Either we need to cast these when storing them
1499 // or reinterpret them lazily (as we do here).
1500 return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T);
1501 }
1502
1503 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
1504 // FIXME: Here we actually perform an implicit conversion from the loaded
1505 // value to the variable type. What we should model is stores to variables
1506 // that blow past the extent of the variable. If the address of the
1507 // variable is reinterpretted, it is possible we stored a different value
1508 // that could fit within the variable. Either we need to cast these when
1509 // storing them or reinterpret them lazily (as we do here).
1510 return CastRetrievedVal(getBindingForVar(B, VR), VR, T);
1511 }
1512
1513 const SVal *V = B.lookup(R, BindingKey::Direct);
1514
1515 // Check if the region has a binding.
1516 if (V)
1517 return *V;
1518
1519 // The location does not have a bound value. This means that it has
1520 // the value it had upon its creation and/or entry to the analyzed
1521 // function/method. These are either symbolic values or 'undefined'.
1522 if (R->hasStackNonParametersStorage()) {
1523 // All stack variables are considered to have undefined values
1524 // upon creation. All heap allocated blocks are considered to
1525 // have undefined values as well unless they are explicitly bound
1526 // to specific values.
1527 return UndefinedVal();
1528 }
1529
1530 // All other values are symbolic.
1531 return svalBuilder.getRegionValueSymbolVal(R);
1532 }
1533
getUnderlyingType(const SubRegion * R)1534 static QualType getUnderlyingType(const SubRegion *R) {
1535 QualType RegionTy;
1536 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R))
1537 RegionTy = TVR->getValueType();
1538
1539 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1540 RegionTy = SR->getSymbol()->getType();
1541
1542 return RegionTy;
1543 }
1544
1545 /// Checks to see if store \p B has a lazy binding for region \p R.
1546 ///
1547 /// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected
1548 /// if there are additional bindings within \p R.
1549 ///
1550 /// Note that unlike RegionStoreManager::findLazyBinding, this will not search
1551 /// for lazy bindings for super-regions of \p R.
1552 static Optional<nonloc::LazyCompoundVal>
getExistingLazyBinding(SValBuilder & SVB,RegionBindingsConstRef B,const SubRegion * R,bool AllowSubregionBindings)1553 getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B,
1554 const SubRegion *R, bool AllowSubregionBindings) {
1555 Optional<SVal> V = B.getDefaultBinding(R);
1556 if (!V)
1557 return None;
1558
1559 Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>();
1560 if (!LCV)
1561 return None;
1562
1563 // If the LCV is for a subregion, the types might not match, and we shouldn't
1564 // reuse the binding.
1565 QualType RegionTy = getUnderlyingType(R);
1566 if (!RegionTy.isNull() &&
1567 !RegionTy->isVoidPointerType()) {
1568 QualType SourceRegionTy = LCV->getRegion()->getValueType();
1569 if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy))
1570 return None;
1571 }
1572
1573 if (!AllowSubregionBindings) {
1574 // If there are any other bindings within this region, we shouldn't reuse
1575 // the top-level binding.
1576 SmallVector<BindingPair, 16> Bindings;
1577 collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R,
1578 /*IncludeAllDefaultBindings=*/true);
1579 if (Bindings.size() > 1)
1580 return None;
1581 }
1582
1583 return *LCV;
1584 }
1585
1586
1587 std::pair<Store, const SubRegion *>
findLazyBinding(RegionBindingsConstRef B,const SubRegion * R,const SubRegion * originalRegion)1588 RegionStoreManager::findLazyBinding(RegionBindingsConstRef B,
1589 const SubRegion *R,
1590 const SubRegion *originalRegion) {
1591 if (originalRegion != R) {
1592 if (Optional<nonloc::LazyCompoundVal> V =
1593 getExistingLazyBinding(svalBuilder, B, R, true))
1594 return std::make_pair(V->getStore(), V->getRegion());
1595 }
1596
1597 typedef std::pair<Store, const SubRegion *> StoreRegionPair;
1598 StoreRegionPair Result = StoreRegionPair();
1599
1600 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
1601 Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()),
1602 originalRegion);
1603
1604 if (Result.second)
1605 Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second);
1606
1607 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
1608 Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()),
1609 originalRegion);
1610
1611 if (Result.second)
1612 Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second);
1613
1614 } else if (const CXXBaseObjectRegion *BaseReg =
1615 dyn_cast<CXXBaseObjectRegion>(R)) {
1616 // C++ base object region is another kind of region that we should blast
1617 // through to look for lazy compound value. It is like a field region.
1618 Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()),
1619 originalRegion);
1620
1621 if (Result.second)
1622 Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg,
1623 Result.second);
1624 }
1625
1626 return Result;
1627 }
1628
getBindingForElement(RegionBindingsConstRef B,const ElementRegion * R)1629 SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B,
1630 const ElementRegion* R) {
1631 // Check if the region has a binding.
1632 if (const Optional<SVal> &V = B.getDirectBinding(R))
1633 return *V;
1634
1635 const MemRegion* superR = R->getSuperRegion();
1636
1637 // Check if the region is an element region of a string literal.
1638 if (const StringRegion *StrR = dyn_cast<StringRegion>(superR)) {
1639 // FIXME: Handle loads from strings where the literal is treated as
1640 // an integer, e.g., *((unsigned int*)"hello")
1641 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType();
1642 if (!Ctx.hasSameUnqualifiedType(T, R->getElementType()))
1643 return UnknownVal();
1644
1645 const StringLiteral *Str = StrR->getStringLiteral();
1646 SVal Idx = R->getIndex();
1647 if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) {
1648 int64_t i = CI->getValue().getSExtValue();
1649 // Abort on string underrun. This can be possible by arbitrary
1650 // clients of getBindingForElement().
1651 if (i < 0)
1652 return UndefinedVal();
1653 int64_t length = Str->getLength();
1654 // Technically, only i == length is guaranteed to be null.
1655 // However, such overflows should be caught before reaching this point;
1656 // the only time such an access would be made is if a string literal was
1657 // used to initialize a larger array.
1658 char c = (i >= length) ? '\0' : Str->getCodeUnit(i);
1659 return svalBuilder.makeIntVal(c, T);
1660 }
1661 } else if (const VarRegion *VR = dyn_cast<VarRegion>(superR)) {
1662 // Check if the containing array has an initialized value that we can trust.
1663 // We can trust a const value or a value of a global initializer in main().
1664 const VarDecl *VD = VR->getDecl();
1665 if (VD->getType().isConstQualified() ||
1666 R->getElementType().isConstQualified() ||
1667 (B.isMainAnalysis() && VD->hasGlobalStorage())) {
1668 if (const Expr *Init = VD->getAnyInitializer()) {
1669 if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1670 // The array index has to be known.
1671 if (auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) {
1672 int64_t i = CI->getValue().getSExtValue();
1673 // If it is known that the index is out of bounds, we can return
1674 // an undefined value.
1675 if (i < 0)
1676 return UndefinedVal();
1677
1678 if (auto CAT = Ctx.getAsConstantArrayType(VD->getType()))
1679 if (CAT->getSize().sle(i))
1680 return UndefinedVal();
1681
1682 // If there is a list, but no init, it must be zero.
1683 if (i >= InitList->getNumInits())
1684 return svalBuilder.makeZeroVal(R->getElementType());
1685
1686 if (const Expr *ElemInit = InitList->getInit(i))
1687 if (Optional<SVal> V = svalBuilder.getConstantVal(ElemInit))
1688 return *V;
1689 }
1690 }
1691 }
1692 }
1693 }
1694
1695 // Check for loads from a code text region. For such loads, just give up.
1696 if (isa<CodeTextRegion>(superR))
1697 return UnknownVal();
1698
1699 // Handle the case where we are indexing into a larger scalar object.
1700 // For example, this handles:
1701 // int x = ...
1702 // char *y = &x;
1703 // return *y;
1704 // FIXME: This is a hack, and doesn't do anything really intelligent yet.
1705 const RegionRawOffset &O = R->getAsArrayOffset();
1706
1707 // If we cannot reason about the offset, return an unknown value.
1708 if (!O.getRegion())
1709 return UnknownVal();
1710
1711 if (const TypedValueRegion *baseR =
1712 dyn_cast_or_null<TypedValueRegion>(O.getRegion())) {
1713 QualType baseT = baseR->getValueType();
1714 if (baseT->isScalarType()) {
1715 QualType elemT = R->getElementType();
1716 if (elemT->isScalarType()) {
1717 if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) {
1718 if (const Optional<SVal> &V = B.getDirectBinding(superR)) {
1719 if (SymbolRef parentSym = V->getAsSymbol())
1720 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1721
1722 if (V->isUnknownOrUndef())
1723 return *V;
1724 // Other cases: give up. We are indexing into a larger object
1725 // that has some value, but we don't know how to handle that yet.
1726 return UnknownVal();
1727 }
1728 }
1729 }
1730 }
1731 }
1732 return getBindingForFieldOrElementCommon(B, R, R->getElementType());
1733 }
1734
getBindingForField(RegionBindingsConstRef B,const FieldRegion * R)1735 SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B,
1736 const FieldRegion* R) {
1737
1738 // Check if the region has a binding.
1739 if (const Optional<SVal> &V = B.getDirectBinding(R))
1740 return *V;
1741
1742 // Is the field declared constant and has an in-class initializer?
1743 const FieldDecl *FD = R->getDecl();
1744 QualType Ty = FD->getType();
1745 if (Ty.isConstQualified())
1746 if (const Expr *Init = FD->getInClassInitializer())
1747 if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1748 return *V;
1749
1750 // If the containing record was initialized, try to get its constant value.
1751 const MemRegion* superR = R->getSuperRegion();
1752 if (const auto *VR = dyn_cast<VarRegion>(superR)) {
1753 const VarDecl *VD = VR->getDecl();
1754 QualType RecordVarTy = VD->getType();
1755 unsigned Index = FD->getFieldIndex();
1756 // Either the record variable or the field has an initializer that we can
1757 // trust. We trust initializers of constants and, additionally, respect
1758 // initializers of globals when analyzing main().
1759 if (RecordVarTy.isConstQualified() || Ty.isConstQualified() ||
1760 (B.isMainAnalysis() && VD->hasGlobalStorage()))
1761 if (const Expr *Init = VD->getAnyInitializer())
1762 if (const auto *InitList = dyn_cast<InitListExpr>(Init)) {
1763 if (Index < InitList->getNumInits()) {
1764 if (const Expr *FieldInit = InitList->getInit(Index))
1765 if (Optional<SVal> V = svalBuilder.getConstantVal(FieldInit))
1766 return *V;
1767 } else {
1768 return svalBuilder.makeZeroVal(Ty);
1769 }
1770 }
1771 }
1772
1773 return getBindingForFieldOrElementCommon(B, R, Ty);
1774 }
1775
1776 Optional<SVal>
getBindingForDerivedDefaultValue(RegionBindingsConstRef B,const MemRegion * superR,const TypedValueRegion * R,QualType Ty)1777 RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
1778 const MemRegion *superR,
1779 const TypedValueRegion *R,
1780 QualType Ty) {
1781
1782 if (const Optional<SVal> &D = B.getDefaultBinding(superR)) {
1783 const SVal &val = D.getValue();
1784 if (SymbolRef parentSym = val.getAsSymbol())
1785 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1786
1787 if (val.isZeroConstant())
1788 return svalBuilder.makeZeroVal(Ty);
1789
1790 if (val.isUnknownOrUndef())
1791 return val;
1792
1793 // Lazy bindings are usually handled through getExistingLazyBinding().
1794 // We should unify these two code paths at some point.
1795 if (val.getAs<nonloc::LazyCompoundVal>() ||
1796 val.getAs<nonloc::CompoundVal>())
1797 return val;
1798
1799 llvm_unreachable("Unknown default value");
1800 }
1801
1802 return None;
1803 }
1804
getLazyBinding(const SubRegion * LazyBindingRegion,RegionBindingsRef LazyBinding)1805 SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion,
1806 RegionBindingsRef LazyBinding) {
1807 SVal Result;
1808 if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion))
1809 Result = getBindingForElement(LazyBinding, ER);
1810 else
1811 Result = getBindingForField(LazyBinding,
1812 cast<FieldRegion>(LazyBindingRegion));
1813
1814 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1815 // default value for /part/ of an aggregate from a default value for the
1816 // /entire/ aggregate. The most common case of this is when struct Outer
1817 // has as its first member a struct Inner, which is copied in from a stack
1818 // variable. In this case, even if the Outer's default value is symbolic, 0,
1819 // or unknown, it gets overridden by the Inner's default value of undefined.
1820 //
1821 // This is a general problem -- if the Inner is zero-initialized, the Outer
1822 // will now look zero-initialized. The proper way to solve this is with a
1823 // new version of RegionStore that tracks the extent of a binding as well
1824 // as the offset.
1825 //
1826 // This hack only takes care of the undefined case because that can very
1827 // quickly result in a warning.
1828 if (Result.isUndef())
1829 Result = UnknownVal();
1830
1831 return Result;
1832 }
1833
1834 SVal
getBindingForFieldOrElementCommon(RegionBindingsConstRef B,const TypedValueRegion * R,QualType Ty)1835 RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
1836 const TypedValueRegion *R,
1837 QualType Ty) {
1838
1839 // At this point we have already checked in either getBindingForElement or
1840 // getBindingForField if 'R' has a direct binding.
1841
1842 // Lazy binding?
1843 Store lazyBindingStore = nullptr;
1844 const SubRegion *lazyBindingRegion = nullptr;
1845 std::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R);
1846 if (lazyBindingRegion)
1847 return getLazyBinding(lazyBindingRegion,
1848 getRegionBindings(lazyBindingStore));
1849
1850 // Record whether or not we see a symbolic index. That can completely
1851 // be out of scope of our lookup.
1852 bool hasSymbolicIndex = false;
1853
1854 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a
1855 // default value for /part/ of an aggregate from a default value for the
1856 // /entire/ aggregate. The most common case of this is when struct Outer
1857 // has as its first member a struct Inner, which is copied in from a stack
1858 // variable. In this case, even if the Outer's default value is symbolic, 0,
1859 // or unknown, it gets overridden by the Inner's default value of undefined.
1860 //
1861 // This is a general problem -- if the Inner is zero-initialized, the Outer
1862 // will now look zero-initialized. The proper way to solve this is with a
1863 // new version of RegionStore that tracks the extent of a binding as well
1864 // as the offset.
1865 //
1866 // This hack only takes care of the undefined case because that can very
1867 // quickly result in a warning.
1868 bool hasPartialLazyBinding = false;
1869
1870 const SubRegion *SR = R;
1871 while (SR) {
1872 const MemRegion *Base = SR->getSuperRegion();
1873 if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) {
1874 if (D->getAs<nonloc::LazyCompoundVal>()) {
1875 hasPartialLazyBinding = true;
1876 break;
1877 }
1878
1879 return *D;
1880 }
1881
1882 if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) {
1883 NonLoc index = ER->getIndex();
1884 if (!index.isConstant())
1885 hasSymbolicIndex = true;
1886 }
1887
1888 // If our super region is a field or element itself, walk up the region
1889 // hierarchy to see if there is a default value installed in an ancestor.
1890 SR = dyn_cast<SubRegion>(Base);
1891 }
1892
1893 if (R->hasStackNonParametersStorage()) {
1894 if (isa<ElementRegion>(R)) {
1895 // Currently we don't reason specially about Clang-style vectors. Check
1896 // if superR is a vector and if so return Unknown.
1897 if (const TypedValueRegion *typedSuperR =
1898 dyn_cast<TypedValueRegion>(R->getSuperRegion())) {
1899 if (typedSuperR->getValueType()->isVectorType())
1900 return UnknownVal();
1901 }
1902 }
1903
1904 // FIXME: We also need to take ElementRegions with symbolic indexes into
1905 // account. This case handles both directly accessing an ElementRegion
1906 // with a symbolic offset, but also fields within an element with
1907 // a symbolic offset.
1908 if (hasSymbolicIndex)
1909 return UnknownVal();
1910
1911 // Additionally allow introspection of a block's internal layout.
1912 if (!hasPartialLazyBinding && !isa<BlockDataRegion>(R->getBaseRegion()))
1913 return UndefinedVal();
1914 }
1915
1916 // All other values are symbolic.
1917 return svalBuilder.getRegionValueSymbolVal(R);
1918 }
1919
getBindingForObjCIvar(RegionBindingsConstRef B,const ObjCIvarRegion * R)1920 SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B,
1921 const ObjCIvarRegion* R) {
1922 // Check if the region has a binding.
1923 if (const Optional<SVal> &V = B.getDirectBinding(R))
1924 return *V;
1925
1926 const MemRegion *superR = R->getSuperRegion();
1927
1928 // Check if the super region has a default binding.
1929 if (const Optional<SVal> &V = B.getDefaultBinding(superR)) {
1930 if (SymbolRef parentSym = V->getAsSymbol())
1931 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R);
1932
1933 // Other cases: give up.
1934 return UnknownVal();
1935 }
1936
1937 return getBindingForLazySymbol(R);
1938 }
1939
getBindingForVar(RegionBindingsConstRef B,const VarRegion * R)1940 SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B,
1941 const VarRegion *R) {
1942
1943 // Check if the region has a binding.
1944 if (Optional<SVal> V = B.getDirectBinding(R))
1945 return *V;
1946
1947 if (Optional<SVal> V = B.getDefaultBinding(R))
1948 return *V;
1949
1950 // Lazily derive a value for the VarRegion.
1951 const VarDecl *VD = R->getDecl();
1952 const MemSpaceRegion *MS = R->getMemorySpace();
1953
1954 // Arguments are always symbolic.
1955 if (isa<StackArgumentsSpaceRegion>(MS))
1956 return svalBuilder.getRegionValueSymbolVal(R);
1957
1958 // Is 'VD' declared constant? If so, retrieve the constant value.
1959 if (VD->getType().isConstQualified()) {
1960 if (const Expr *Init = VD->getAnyInitializer()) {
1961 if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1962 return *V;
1963
1964 // If the variable is const qualified and has an initializer but
1965 // we couldn't evaluate initializer to a value, treat the value as
1966 // unknown.
1967 return UnknownVal();
1968 }
1969 }
1970
1971 // This must come after the check for constants because closure-captured
1972 // constant variables may appear in UnknownSpaceRegion.
1973 if (isa<UnknownSpaceRegion>(MS))
1974 return svalBuilder.getRegionValueSymbolVal(R);
1975
1976 if (isa<GlobalsSpaceRegion>(MS)) {
1977 QualType T = VD->getType();
1978
1979 // If we're in main(), then global initializers have not become stale yet.
1980 if (B.isMainAnalysis())
1981 if (const Expr *Init = VD->getAnyInitializer())
1982 if (Optional<SVal> V = svalBuilder.getConstantVal(Init))
1983 return *V;
1984
1985 // Function-scoped static variables are default-initialized to 0; if they
1986 // have an initializer, it would have been processed by now.
1987 // FIXME: This is only true when we're starting analysis from main().
1988 // We're losing a lot of coverage here.
1989 if (isa<StaticGlobalSpaceRegion>(MS))
1990 return svalBuilder.makeZeroVal(T);
1991
1992 if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) {
1993 assert(!V->getAs<nonloc::LazyCompoundVal>());
1994 return V.getValue();
1995 }
1996
1997 return svalBuilder.getRegionValueSymbolVal(R);
1998 }
1999
2000 return UndefinedVal();
2001 }
2002
getBindingForLazySymbol(const TypedValueRegion * R)2003 SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
2004 // All other values are symbolic.
2005 return svalBuilder.getRegionValueSymbolVal(R);
2006 }
2007
2008 const RegionStoreManager::SValListTy &
getInterestingValues(nonloc::LazyCompoundVal LCV)2009 RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) {
2010 // First, check the cache.
2011 LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData());
2012 if (I != LazyBindingsMap.end())
2013 return I->second;
2014
2015 // If we don't have a list of values cached, start constructing it.
2016 SValListTy List;
2017
2018 const SubRegion *LazyR = LCV.getRegion();
2019 RegionBindingsRef B = getRegionBindings(LCV.getStore());
2020
2021 // If this region had /no/ bindings at the time, there are no interesting
2022 // values to return.
2023 const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion());
2024 if (!Cluster)
2025 return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2026
2027 SmallVector<BindingPair, 32> Bindings;
2028 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR,
2029 /*IncludeAllDefaultBindings=*/true);
2030 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(),
2031 E = Bindings.end();
2032 I != E; ++I) {
2033 SVal V = I->second;
2034 if (V.isUnknownOrUndef() || V.isConstant())
2035 continue;
2036
2037 if (Optional<nonloc::LazyCompoundVal> InnerLCV =
2038 V.getAs<nonloc::LazyCompoundVal>()) {
2039 const SValListTy &InnerList = getInterestingValues(*InnerLCV);
2040 List.insert(List.end(), InnerList.begin(), InnerList.end());
2041 continue;
2042 }
2043
2044 List.push_back(V);
2045 }
2046
2047 return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2048 }
2049
createLazyBinding(RegionBindingsConstRef B,const TypedValueRegion * R)2050 NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B,
2051 const TypedValueRegion *R) {
2052 if (Optional<nonloc::LazyCompoundVal> V =
2053 getExistingLazyBinding(svalBuilder, B, R, false))
2054 return *V;
2055
2056 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R);
2057 }
2058
isRecordEmpty(const RecordDecl * RD)2059 static bool isRecordEmpty(const RecordDecl *RD) {
2060 if (!RD->field_empty())
2061 return false;
2062 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD))
2063 return CRD->getNumBases() == 0;
2064 return true;
2065 }
2066
getBindingForStruct(RegionBindingsConstRef B,const TypedValueRegion * R)2067 SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B,
2068 const TypedValueRegion *R) {
2069 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl();
2070 if (!RD->getDefinition() || isRecordEmpty(RD))
2071 return UnknownVal();
2072
2073 return createLazyBinding(B, R);
2074 }
2075
getBindingForArray(RegionBindingsConstRef B,const TypedValueRegion * R)2076 SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B,
2077 const TypedValueRegion *R) {
2078 assert(Ctx.getAsConstantArrayType(R->getValueType()) &&
2079 "Only constant array types can have compound bindings.");
2080
2081 return createLazyBinding(B, R);
2082 }
2083
includedInBindings(Store store,const MemRegion * region) const2084 bool RegionStoreManager::includedInBindings(Store store,
2085 const MemRegion *region) const {
2086 RegionBindingsRef B = getRegionBindings(store);
2087 region = region->getBaseRegion();
2088
2089 // Quick path: if the base is the head of a cluster, the region is live.
2090 if (B.lookup(region))
2091 return true;
2092
2093 // Slow path: if the region is the VALUE of any binding, it is live.
2094 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) {
2095 const ClusterBindings &Cluster = RI.getData();
2096 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2097 CI != CE; ++CI) {
2098 const SVal &D = CI.getData();
2099 if (const MemRegion *R = D.getAsRegion())
2100 if (R->getBaseRegion() == region)
2101 return true;
2102 }
2103 }
2104
2105 return false;
2106 }
2107
2108 //===----------------------------------------------------------------------===//
2109 // Binding values to regions.
2110 //===----------------------------------------------------------------------===//
2111
killBinding(Store ST,Loc L)2112 StoreRef RegionStoreManager::killBinding(Store ST, Loc L) {
2113 if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>())
2114 if (const MemRegion* R = LV->getRegion())
2115 return StoreRef(getRegionBindings(ST).removeBinding(R)
2116 .asImmutableMap()
2117 .getRootWithoutRetain(),
2118 *this);
2119
2120 return StoreRef(ST, *this);
2121 }
2122
2123 RegionBindingsRef
bind(RegionBindingsConstRef B,Loc L,SVal V)2124 RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) {
2125 if (L.getAs<loc::ConcreteInt>())
2126 return B;
2127
2128 // If we get here, the location should be a region.
2129 const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion();
2130
2131 // Check if the region is a struct region.
2132 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) {
2133 QualType Ty = TR->getValueType();
2134 if (Ty->isArrayType())
2135 return bindArray(B, TR, V);
2136 if (Ty->isStructureOrClassType())
2137 return bindStruct(B, TR, V);
2138 if (Ty->isVectorType())
2139 return bindVector(B, TR, V);
2140 if (Ty->isUnionType())
2141 return bindAggregate(B, TR, V);
2142 }
2143
2144 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
2145 // Binding directly to a symbolic region should be treated as binding
2146 // to element 0.
2147 QualType T = SR->getSymbol()->getType();
2148 if (T->isAnyPointerType() || T->isReferenceType())
2149 T = T->getPointeeType();
2150
2151 R = GetElementZeroRegion(SR, T);
2152 }
2153
2154 assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) &&
2155 "'this' pointer is not an l-value and is not assignable");
2156
2157 // Clear out bindings that may overlap with this binding.
2158 RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R));
2159 return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V);
2160 }
2161
2162 RegionBindingsRef
setImplicitDefaultValue(RegionBindingsConstRef B,const MemRegion * R,QualType T)2163 RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B,
2164 const MemRegion *R,
2165 QualType T) {
2166 SVal V;
2167
2168 if (Loc::isLocType(T))
2169 V = svalBuilder.makeNull();
2170 else if (T->isIntegralOrEnumerationType())
2171 V = svalBuilder.makeZeroVal(T);
2172 else if (T->isStructureOrClassType() || T->isArrayType()) {
2173 // Set the default value to a zero constant when it is a structure
2174 // or array. The type doesn't really matter.
2175 V = svalBuilder.makeZeroVal(Ctx.IntTy);
2176 }
2177 else {
2178 // We can't represent values of this type, but we still need to set a value
2179 // to record that the region has been initialized.
2180 // If this assertion ever fires, a new case should be added above -- we
2181 // should know how to default-initialize any value we can symbolicate.
2182 assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
2183 V = UnknownVal();
2184 }
2185
2186 return B.addBinding(R, BindingKey::Default, V);
2187 }
2188
2189 RegionBindingsRef
bindArray(RegionBindingsConstRef B,const TypedValueRegion * R,SVal Init)2190 RegionStoreManager::bindArray(RegionBindingsConstRef B,
2191 const TypedValueRegion* R,
2192 SVal Init) {
2193
2194 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType()));
2195 QualType ElementTy = AT->getElementType();
2196 Optional<uint64_t> Size;
2197
2198 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT))
2199 Size = CAT->getSize().getZExtValue();
2200
2201 // Check if the init expr is a literal. If so, bind the rvalue instead.
2202 // FIXME: It's not responsibility of the Store to transform this lvalue
2203 // to rvalue. ExprEngine or maybe even CFG should do this before binding.
2204 if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) {
2205 SVal V = getBinding(B.asStore(), *MRV, R->getValueType());
2206 return bindAggregate(B, R, V);
2207 }
2208
2209 // Handle lazy compound values.
2210 if (Init.getAs<nonloc::LazyCompoundVal>())
2211 return bindAggregate(B, R, Init);
2212
2213 if (Init.isUnknown())
2214 return bindAggregate(B, R, UnknownVal());
2215
2216 // Remaining case: explicit compound values.
2217 const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>();
2218 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2219 uint64_t i = 0;
2220
2221 RegionBindingsRef NewB(B);
2222
2223 for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) {
2224 // The init list might be shorter than the array length.
2225 if (VI == VE)
2226 break;
2227
2228 const NonLoc &Idx = svalBuilder.makeArrayIndex(i);
2229 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx);
2230
2231 if (ElementTy->isStructureOrClassType())
2232 NewB = bindStruct(NewB, ER, *VI);
2233 else if (ElementTy->isArrayType())
2234 NewB = bindArray(NewB, ER, *VI);
2235 else
2236 NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2237 }
2238
2239 // If the init list is shorter than the array length (or the array has
2240 // variable length), set the array default value. Values that are already set
2241 // are not overwritten.
2242 if (!Size.hasValue() || i < Size.getValue())
2243 NewB = setImplicitDefaultValue(NewB, R, ElementTy);
2244
2245 return NewB;
2246 }
2247
bindVector(RegionBindingsConstRef B,const TypedValueRegion * R,SVal V)2248 RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B,
2249 const TypedValueRegion* R,
2250 SVal V) {
2251 QualType T = R->getValueType();
2252 const VectorType *VT = T->castAs<VectorType>(); // Use castAs for typedefs.
2253
2254 // Handle lazy compound values and symbolic values.
2255 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>())
2256 return bindAggregate(B, R, V);
2257
2258 // We may get non-CompoundVal accidentally due to imprecise cast logic or
2259 // that we are binding symbolic struct value. Kill the field values, and if
2260 // the value is symbolic go and bind it as a "default" binding.
2261 if (!V.getAs<nonloc::CompoundVal>()) {
2262 return bindAggregate(B, R, UnknownVal());
2263 }
2264
2265 QualType ElemType = VT->getElementType();
2266 nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>();
2267 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2268 unsigned index = 0, numElements = VT->getNumElements();
2269 RegionBindingsRef NewB(B);
2270
2271 for ( ; index != numElements ; ++index) {
2272 if (VI == VE)
2273 break;
2274
2275 NonLoc Idx = svalBuilder.makeArrayIndex(index);
2276 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx);
2277
2278 if (ElemType->isArrayType())
2279 NewB = bindArray(NewB, ER, *VI);
2280 else if (ElemType->isStructureOrClassType())
2281 NewB = bindStruct(NewB, ER, *VI);
2282 else
2283 NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
2284 }
2285 return NewB;
2286 }
2287
2288 Optional<RegionBindingsRef>
tryBindSmallStruct(RegionBindingsConstRef B,const TypedValueRegion * R,const RecordDecl * RD,nonloc::LazyCompoundVal LCV)2289 RegionStoreManager::tryBindSmallStruct(RegionBindingsConstRef B,
2290 const TypedValueRegion *R,
2291 const RecordDecl *RD,
2292 nonloc::LazyCompoundVal LCV) {
2293 FieldVector Fields;
2294
2295 if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(RD))
2296 if (Class->getNumBases() != 0 || Class->getNumVBases() != 0)
2297 return None;
2298
2299 for (const auto *FD : RD->fields()) {
2300 if (FD->isUnnamedBitfield())
2301 continue;
2302
2303 // If there are too many fields, or if any of the fields are aggregates,
2304 // just use the LCV as a default binding.
2305 if (Fields.size() == SmallStructLimit)
2306 return None;
2307
2308 QualType Ty = FD->getType();
2309 if (!(Ty->isScalarType() || Ty->isReferenceType()))
2310 return None;
2311
2312 Fields.push_back(FD);
2313 }
2314
2315 RegionBindingsRef NewB = B;
2316
2317 for (FieldVector::iterator I = Fields.begin(), E = Fields.end(); I != E; ++I){
2318 const FieldRegion *SourceFR = MRMgr.getFieldRegion(*I, LCV.getRegion());
2319 SVal V = getBindingForField(getRegionBindings(LCV.getStore()), SourceFR);
2320
2321 const FieldRegion *DestFR = MRMgr.getFieldRegion(*I, R);
2322 NewB = bind(NewB, loc::MemRegionVal(DestFR), V);
2323 }
2324
2325 return NewB;
2326 }
2327
bindStruct(RegionBindingsConstRef B,const TypedValueRegion * R,SVal V)2328 RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B,
2329 const TypedValueRegion* R,
2330 SVal V) {
2331 if (!Features.supportsFields())
2332 return B;
2333
2334 QualType T = R->getValueType();
2335 assert(T->isStructureOrClassType());
2336
2337 const RecordType* RT = T->castAs<RecordType>();
2338 const RecordDecl *RD = RT->getDecl();
2339
2340 if (!RD->isCompleteDefinition())
2341 return B;
2342
2343 // Handle lazy compound values and symbolic values.
2344 if (Optional<nonloc::LazyCompoundVal> LCV =
2345 V.getAs<nonloc::LazyCompoundVal>()) {
2346 if (Optional<RegionBindingsRef> NewB = tryBindSmallStruct(B, R, RD, *LCV))
2347 return *NewB;
2348 return bindAggregate(B, R, V);
2349 }
2350 if (V.getAs<nonloc::SymbolVal>())
2351 return bindAggregate(B, R, V);
2352
2353 // We may get non-CompoundVal accidentally due to imprecise cast logic or
2354 // that we are binding symbolic struct value. Kill the field values, and if
2355 // the value is symbolic go and bind it as a "default" binding.
2356 if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>())
2357 return bindAggregate(B, R, UnknownVal());
2358
2359 // The raw CompoundVal is essentially a symbolic InitListExpr: an (immutable)
2360 // list of other values. It appears pretty much only when there's an actual
2361 // initializer list expression in the program, and the analyzer tries to
2362 // unwrap it as soon as possible.
2363 // This code is where such unwrap happens: when the compound value is put into
2364 // the object that it was supposed to initialize (it's an *initializer* list,
2365 // after all), instead of binding the whole value to the whole object, we bind
2366 // sub-values to sub-objects. Sub-values may themselves be compound values,
2367 // and in this case the procedure becomes recursive.
2368 // FIXME: The annoying part about compound values is that they don't carry
2369 // any sort of information about which value corresponds to which sub-object.
2370 // It's simply a list of values in the middle of nowhere; we expect to match
2371 // them to sub-objects, essentially, "by index": first value binds to
2372 // the first field, second value binds to the second field, etc.
2373 // It would have been much safer to organize non-lazy compound values as
2374 // a mapping from fields/bases to values.
2375 const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>();
2376 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2377
2378 RegionBindingsRef NewB(B);
2379
2380 // In C++17 aggregates may have base classes, handle those as well.
2381 // They appear before fields in the initializer list / compound value.
2382 if (const auto *CRD = dyn_cast<CXXRecordDecl>(RD)) {
2383 // If the object was constructed with a constructor, its value is a
2384 // LazyCompoundVal. If it's a raw CompoundVal, it means that we're
2385 // performing aggregate initialization. The only exception from this
2386 // rule is sending an Objective-C++ message that returns a C++ object
2387 // to a nil receiver; in this case the semantics is to return a
2388 // zero-initialized object even if it's a C++ object that doesn't have
2389 // this sort of constructor; the CompoundVal is empty in this case.
2390 assert((CRD->isAggregate() || (Ctx.getLangOpts().ObjC && VI == VE)) &&
2391 "Non-aggregates are constructed with a constructor!");
2392
2393 for (const auto &B : CRD->bases()) {
2394 // (Multiple inheritance is fine though.)
2395 assert(!B.isVirtual() && "Aggregates cannot have virtual base classes!");
2396
2397 if (VI == VE)
2398 break;
2399
2400 QualType BTy = B.getType();
2401 assert(BTy->isStructureOrClassType() && "Base classes must be classes!");
2402
2403 const CXXRecordDecl *BRD = BTy->getAsCXXRecordDecl();
2404 assert(BRD && "Base classes must be C++ classes!");
2405
2406 const CXXBaseObjectRegion *BR =
2407 MRMgr.getCXXBaseObjectRegion(BRD, R, /*IsVirtual=*/false);
2408
2409 NewB = bindStruct(NewB, BR, *VI);
2410
2411 ++VI;
2412 }
2413 }
2414
2415 RecordDecl::field_iterator FI, FE;
2416
2417 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
2418
2419 if (VI == VE)
2420 break;
2421
2422 // Skip any unnamed bitfields to stay in sync with the initializers.
2423 if (FI->isUnnamedBitfield())
2424 continue;
2425
2426 QualType FTy = FI->getType();
2427 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R);
2428
2429 if (FTy->isArrayType())
2430 NewB = bindArray(NewB, FR, *VI);
2431 else if (FTy->isStructureOrClassType())
2432 NewB = bindStruct(NewB, FR, *VI);
2433 else
2434 NewB = bind(NewB, loc::MemRegionVal(FR), *VI);
2435 ++VI;
2436 }
2437
2438 // There may be fewer values in the initialize list than the fields of struct.
2439 if (FI != FE) {
2440 NewB = NewB.addBinding(R, BindingKey::Default,
2441 svalBuilder.makeIntVal(0, false));
2442 }
2443
2444 return NewB;
2445 }
2446
2447 RegionBindingsRef
bindAggregate(RegionBindingsConstRef B,const TypedRegion * R,SVal Val)2448 RegionStoreManager::bindAggregate(RegionBindingsConstRef B,
2449 const TypedRegion *R,
2450 SVal Val) {
2451 // Remove the old bindings, using 'R' as the root of all regions
2452 // we will invalidate. Then add the new binding.
2453 return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val);
2454 }
2455
2456 //===----------------------------------------------------------------------===//
2457 // State pruning.
2458 //===----------------------------------------------------------------------===//
2459
2460 namespace {
2461 class RemoveDeadBindingsWorker
2462 : public ClusterAnalysis<RemoveDeadBindingsWorker> {
2463 SmallVector<const SymbolicRegion *, 12> Postponed;
2464 SymbolReaper &SymReaper;
2465 const StackFrameContext *CurrentLCtx;
2466
2467 public:
RemoveDeadBindingsWorker(RegionStoreManager & rm,ProgramStateManager & stateMgr,RegionBindingsRef b,SymbolReaper & symReaper,const StackFrameContext * LCtx)2468 RemoveDeadBindingsWorker(RegionStoreManager &rm,
2469 ProgramStateManager &stateMgr,
2470 RegionBindingsRef b, SymbolReaper &symReaper,
2471 const StackFrameContext *LCtx)
2472 : ClusterAnalysis<RemoveDeadBindingsWorker>(rm, stateMgr, b),
2473 SymReaper(symReaper), CurrentLCtx(LCtx) {}
2474
2475 // Called by ClusterAnalysis.
2476 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C);
2477 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
2478 using ClusterAnalysis<RemoveDeadBindingsWorker>::VisitCluster;
2479
2480 using ClusterAnalysis::AddToWorkList;
2481
2482 bool AddToWorkList(const MemRegion *R);
2483
2484 bool UpdatePostponed();
2485 void VisitBinding(SVal V);
2486 };
2487 }
2488
AddToWorkList(const MemRegion * R)2489 bool RemoveDeadBindingsWorker::AddToWorkList(const MemRegion *R) {
2490 const MemRegion *BaseR = R->getBaseRegion();
2491 return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR));
2492 }
2493
VisitAddedToCluster(const MemRegion * baseR,const ClusterBindings & C)2494 void RemoveDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
2495 const ClusterBindings &C) {
2496
2497 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) {
2498 if (SymReaper.isLive(VR))
2499 AddToWorkList(baseR, &C);
2500
2501 return;
2502 }
2503
2504 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) {
2505 if (SymReaper.isLive(SR->getSymbol()))
2506 AddToWorkList(SR, &C);
2507 else
2508 Postponed.push_back(SR);
2509
2510 return;
2511 }
2512
2513 if (isa<NonStaticGlobalSpaceRegion>(baseR)) {
2514 AddToWorkList(baseR, &C);
2515 return;
2516 }
2517
2518 // CXXThisRegion in the current or parent location context is live.
2519 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) {
2520 const auto *StackReg =
2521 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion());
2522 const StackFrameContext *RegCtx = StackReg->getStackFrame();
2523 if (CurrentLCtx &&
2524 (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx)))
2525 AddToWorkList(TR, &C);
2526 }
2527 }
2528
VisitCluster(const MemRegion * baseR,const ClusterBindings * C)2529 void RemoveDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
2530 const ClusterBindings *C) {
2531 if (!C)
2532 return;
2533
2534 // Mark the symbol for any SymbolicRegion with live bindings as live itself.
2535 // This means we should continue to track that symbol.
2536 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR))
2537 SymReaper.markLive(SymR->getSymbol());
2538
2539 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) {
2540 // Element index of a binding key is live.
2541 SymReaper.markElementIndicesLive(I.getKey().getRegion());
2542
2543 VisitBinding(I.getData());
2544 }
2545 }
2546
VisitBinding(SVal V)2547 void RemoveDeadBindingsWorker::VisitBinding(SVal V) {
2548 // Is it a LazyCompoundVal? All referenced regions are live as well.
2549 if (Optional<nonloc::LazyCompoundVal> LCS =
2550 V.getAs<nonloc::LazyCompoundVal>()) {
2551
2552 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS);
2553
2554 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(),
2555 E = Vals.end();
2556 I != E; ++I)
2557 VisitBinding(*I);
2558
2559 return;
2560 }
2561
2562 // If V is a region, then add it to the worklist.
2563 if (const MemRegion *R = V.getAsRegion()) {
2564 AddToWorkList(R);
2565 SymReaper.markLive(R);
2566
2567 // All regions captured by a block are also live.
2568 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) {
2569 BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(),
2570 E = BR->referenced_vars_end();
2571 for ( ; I != E; ++I)
2572 AddToWorkList(I.getCapturedRegion());
2573 }
2574 }
2575
2576
2577 // Update the set of live symbols.
2578 for (auto SI = V.symbol_begin(), SE = V.symbol_end(); SI!=SE; ++SI)
2579 SymReaper.markLive(*SI);
2580 }
2581
UpdatePostponed()2582 bool RemoveDeadBindingsWorker::UpdatePostponed() {
2583 // See if any postponed SymbolicRegions are actually live now, after
2584 // having done a scan.
2585 bool Changed = false;
2586
2587 for (auto I = Postponed.begin(), E = Postponed.end(); I != E; ++I) {
2588 if (const SymbolicRegion *SR = *I) {
2589 if (SymReaper.isLive(SR->getSymbol())) {
2590 Changed |= AddToWorkList(SR);
2591 *I = nullptr;
2592 }
2593 }
2594 }
2595
2596 return Changed;
2597 }
2598
removeDeadBindings(Store store,const StackFrameContext * LCtx,SymbolReaper & SymReaper)2599 StoreRef RegionStoreManager::removeDeadBindings(Store store,
2600 const StackFrameContext *LCtx,
2601 SymbolReaper& SymReaper) {
2602 RegionBindingsRef B = getRegionBindings(store);
2603 RemoveDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
2604 W.GenerateClusters();
2605
2606 // Enqueue the region roots onto the worklist.
2607 for (SymbolReaper::region_iterator I = SymReaper.region_begin(),
2608 E = SymReaper.region_end(); I != E; ++I) {
2609 W.AddToWorkList(*I);
2610 }
2611
2612 do W.RunWorkList(); while (W.UpdatePostponed());
2613
2614 // We have now scanned the store, marking reachable regions and symbols
2615 // as live. We now remove all the regions that are dead from the store
2616 // as well as update DSymbols with the set symbols that are now dead.
2617 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) {
2618 const MemRegion *Base = I.getKey();
2619
2620 // If the cluster has been visited, we know the region has been marked.
2621 // Otherwise, remove the dead entry.
2622 if (!W.isVisited(Base))
2623 B = B.remove(Base);
2624 }
2625
2626 return StoreRef(B.asStore(), *this);
2627 }
2628
2629 //===----------------------------------------------------------------------===//
2630 // Utility methods.
2631 //===----------------------------------------------------------------------===//
2632
printJson(raw_ostream & Out,Store S,const char * NL,unsigned int Space,bool IsDot) const2633 void RegionStoreManager::printJson(raw_ostream &Out, Store S, const char *NL,
2634 unsigned int Space, bool IsDot) const {
2635 RegionBindingsRef Bindings = getRegionBindings(S);
2636
2637 Indent(Out, Space, IsDot) << "\"store\": ";
2638
2639 if (Bindings.isEmpty()) {
2640 Out << "null," << NL;
2641 return;
2642 }
2643
2644 Out << "{ \"pointer\": \"" << Bindings.asStore() << "\", \"items\": [" << NL;
2645 Bindings.printJson(Out, NL, Space + 1, IsDot);
2646 Indent(Out, Space, IsDot) << "]}," << NL;
2647 }
2648