1 //== RegionStore.cpp - Field-sensitive store model --------------*- C++ -*--==// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines a basic region store model. In this model, we do have field 11 // sensitivity. But we assume nothing about the heap shape. So recursive data 12 // structures are largely ignored. Basically we do 1-limiting analysis. 13 // Parameter pointers are assumed with no aliasing. Pointee objects of 14 // parameters are created lazily. 15 // 16 //===----------------------------------------------------------------------===// 17 #include "clang/AST/Attr.h" 18 #include "clang/AST/CharUnits.h" 19 #include "clang/Analysis/Analyses/LiveVariables.h" 20 #include "clang/Analysis/AnalysisContext.h" 21 #include "clang/Basic/TargetInfo.h" 22 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 23 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 24 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" 25 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 26 #include "llvm/ADT/ImmutableList.h" 27 #include "llvm/ADT/ImmutableMap.h" 28 #include "llvm/ADT/Optional.h" 29 #include "llvm/Support/raw_ostream.h" 30 31 using namespace clang; 32 using namespace ento; 33 34 //===----------------------------------------------------------------------===// 35 // Representation of binding keys. 36 //===----------------------------------------------------------------------===// 37 38 namespace { 39 class BindingKey { 40 public: 41 enum Kind { Default = 0x0, Direct = 0x1 }; 42 private: 43 enum { Symbolic = 0x2 }; 44 45 llvm::PointerIntPair<const MemRegion *, 2> P; 46 uint64_t Data; 47 48 /// Create a key for a binding to region \p r, which has a symbolic offset 49 /// from region \p Base. 50 explicit BindingKey(const SubRegion *r, const SubRegion *Base, Kind k) 51 : P(r, k | Symbolic), Data(reinterpret_cast<uintptr_t>(Base)) { 52 assert(r && Base && "Must have known regions."); 53 assert(getConcreteOffsetRegion() == Base && "Failed to store base region"); 54 } 55 56 /// Create a key for a binding at \p offset from base region \p r. 57 explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k) 58 : P(r, k), Data(offset) { 59 assert(r && "Must have known regions."); 60 assert(getOffset() == offset && "Failed to store offset"); 61 assert((r == r->getBaseRegion() || isa<ObjCIvarRegion>(r)) && "Not a base"); 62 } 63 public: 64 65 bool isDirect() const { return P.getInt() & Direct; } 66 bool hasSymbolicOffset() const { return P.getInt() & Symbolic; } 67 68 const MemRegion *getRegion() const { return P.getPointer(); } 69 uint64_t getOffset() const { 70 assert(!hasSymbolicOffset()); 71 return Data; 72 } 73 74 const SubRegion *getConcreteOffsetRegion() const { 75 assert(hasSymbolicOffset()); 76 return reinterpret_cast<const SubRegion *>(static_cast<uintptr_t>(Data)); 77 } 78 79 const MemRegion *getBaseRegion() const { 80 if (hasSymbolicOffset()) 81 return getConcreteOffsetRegion()->getBaseRegion(); 82 return getRegion()->getBaseRegion(); 83 } 84 85 void Profile(llvm::FoldingSetNodeID& ID) const { 86 ID.AddPointer(P.getOpaqueValue()); 87 ID.AddInteger(Data); 88 } 89 90 static BindingKey Make(const MemRegion *R, Kind k); 91 92 bool operator<(const BindingKey &X) const { 93 if (P.getOpaqueValue() < X.P.getOpaqueValue()) 94 return true; 95 if (P.getOpaqueValue() > X.P.getOpaqueValue()) 96 return false; 97 return Data < X.Data; 98 } 99 100 bool operator==(const BindingKey &X) const { 101 return P.getOpaqueValue() == X.P.getOpaqueValue() && 102 Data == X.Data; 103 } 104 105 LLVM_ATTRIBUTE_USED void dump() const; 106 }; 107 } // end anonymous namespace 108 109 BindingKey BindingKey::Make(const MemRegion *R, Kind k) { 110 const RegionOffset &RO = R->getAsOffset(); 111 if (RO.hasSymbolicOffset()) 112 return BindingKey(cast<SubRegion>(R), cast<SubRegion>(RO.getRegion()), k); 113 114 return BindingKey(RO.getRegion(), RO.getOffset(), k); 115 } 116 117 namespace llvm { 118 static inline 119 raw_ostream &operator<<(raw_ostream &os, BindingKey K) { 120 os << '(' << K.getRegion(); 121 if (!K.hasSymbolicOffset()) 122 os << ',' << K.getOffset(); 123 os << ',' << (K.isDirect() ? "direct" : "default") 124 << ')'; 125 return os; 126 } 127 128 template <typename T> struct isPodLike; 129 template <> struct isPodLike<BindingKey> { 130 static const bool value = true; 131 }; 132 } // end llvm namespace 133 134 void BindingKey::dump() const { 135 llvm::errs() << *this; 136 } 137 138 //===----------------------------------------------------------------------===// 139 // Actual Store type. 140 //===----------------------------------------------------------------------===// 141 142 typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings; 143 typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef; 144 typedef std::pair<BindingKey, SVal> BindingPair; 145 146 typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings> 147 RegionBindings; 148 149 namespace { 150 class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *, 151 ClusterBindings> { 152 ClusterBindings::Factory &CBFactory; 153 public: 154 typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings> 155 ParentTy; 156 157 RegionBindingsRef(ClusterBindings::Factory &CBFactory, 158 const RegionBindings::TreeTy *T, 159 RegionBindings::TreeTy::Factory *F) 160 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F), 161 CBFactory(CBFactory) {} 162 163 RegionBindingsRef(const ParentTy &P, ClusterBindings::Factory &CBFactory) 164 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P), 165 CBFactory(CBFactory) {} 166 167 RegionBindingsRef add(key_type_ref K, data_type_ref D) const { 168 return RegionBindingsRef(static_cast<const ParentTy*>(this)->add(K, D), 169 CBFactory); 170 } 171 172 RegionBindingsRef remove(key_type_ref K) const { 173 return RegionBindingsRef(static_cast<const ParentTy*>(this)->remove(K), 174 CBFactory); 175 } 176 177 RegionBindingsRef addBinding(BindingKey K, SVal V) const; 178 179 RegionBindingsRef addBinding(const MemRegion *R, 180 BindingKey::Kind k, SVal V) const; 181 182 RegionBindingsRef &operator=(const RegionBindingsRef &X) { 183 *static_cast<ParentTy*>(this) = X; 184 return *this; 185 } 186 187 const SVal *lookup(BindingKey K) const; 188 const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const; 189 const ClusterBindings *lookup(const MemRegion *R) const { 190 return static_cast<const ParentTy*>(this)->lookup(R); 191 } 192 193 RegionBindingsRef removeBinding(BindingKey K); 194 195 RegionBindingsRef removeBinding(const MemRegion *R, 196 BindingKey::Kind k); 197 198 RegionBindingsRef removeBinding(const MemRegion *R) { 199 return removeBinding(R, BindingKey::Direct). 200 removeBinding(R, BindingKey::Default); 201 } 202 203 Optional<SVal> getDirectBinding(const MemRegion *R) const; 204 205 /// getDefaultBinding - Returns an SVal* representing an optional default 206 /// binding associated with a region and its subregions. 207 Optional<SVal> getDefaultBinding(const MemRegion *R) const; 208 209 /// Return the internal tree as a Store. 210 Store asStore() const { 211 return asImmutableMap().getRootWithoutRetain(); 212 } 213 214 void dump(raw_ostream &OS, const char *nl) const { 215 for (iterator I = begin(), E = end(); I != E; ++I) { 216 const ClusterBindings &Cluster = I.getData(); 217 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 218 CI != CE; ++CI) { 219 OS << ' ' << CI.getKey() << " : " << CI.getData() << nl; 220 } 221 OS << nl; 222 } 223 } 224 225 LLVM_ATTRIBUTE_USED void dump() const { 226 dump(llvm::errs(), "\n"); 227 } 228 }; 229 } // end anonymous namespace 230 231 typedef const RegionBindingsRef& RegionBindingsConstRef; 232 233 Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const { 234 return Optional<SVal>::create(lookup(R, BindingKey::Direct)); 235 } 236 237 Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const { 238 if (R->isBoundable()) 239 if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) 240 if (TR->getValueType()->isUnionType()) 241 return UnknownVal(); 242 243 return Optional<SVal>::create(lookup(R, BindingKey::Default)); 244 } 245 246 RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const { 247 const MemRegion *Base = K.getBaseRegion(); 248 249 const ClusterBindings *ExistingCluster = lookup(Base); 250 ClusterBindings Cluster = (ExistingCluster ? *ExistingCluster 251 : CBFactory.getEmptyMap()); 252 253 ClusterBindings NewCluster = CBFactory.add(Cluster, K, V); 254 return add(Base, NewCluster); 255 } 256 257 258 RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R, 259 BindingKey::Kind k, 260 SVal V) const { 261 return addBinding(BindingKey::Make(R, k), V); 262 } 263 264 const SVal *RegionBindingsRef::lookup(BindingKey K) const { 265 const ClusterBindings *Cluster = lookup(K.getBaseRegion()); 266 if (!Cluster) 267 return 0; 268 return Cluster->lookup(K); 269 } 270 271 const SVal *RegionBindingsRef::lookup(const MemRegion *R, 272 BindingKey::Kind k) const { 273 return lookup(BindingKey::Make(R, k)); 274 } 275 276 RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) { 277 const MemRegion *Base = K.getBaseRegion(); 278 const ClusterBindings *Cluster = lookup(Base); 279 if (!Cluster) 280 return *this; 281 282 ClusterBindings NewCluster = CBFactory.remove(*Cluster, K); 283 if (NewCluster.isEmpty()) 284 return remove(Base); 285 return add(Base, NewCluster); 286 } 287 288 RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R, 289 BindingKey::Kind k){ 290 return removeBinding(BindingKey::Make(R, k)); 291 } 292 293 //===----------------------------------------------------------------------===// 294 // Fine-grained control of RegionStoreManager. 295 //===----------------------------------------------------------------------===// 296 297 namespace { 298 struct minimal_features_tag {}; 299 struct maximal_features_tag {}; 300 301 class RegionStoreFeatures { 302 bool SupportsFields; 303 public: 304 RegionStoreFeatures(minimal_features_tag) : 305 SupportsFields(false) {} 306 307 RegionStoreFeatures(maximal_features_tag) : 308 SupportsFields(true) {} 309 310 void enableFields(bool t) { SupportsFields = t; } 311 312 bool supportsFields() const { return SupportsFields; } 313 }; 314 } 315 316 //===----------------------------------------------------------------------===// 317 // Main RegionStore logic. 318 //===----------------------------------------------------------------------===// 319 320 namespace { 321 322 class RegionStoreManager : public StoreManager { 323 public: 324 const RegionStoreFeatures Features; 325 RegionBindings::Factory RBFactory; 326 mutable ClusterBindings::Factory CBFactory; 327 328 typedef std::vector<SVal> SValListTy; 329 private: 330 typedef llvm::DenseMap<const LazyCompoundValData *, 331 SValListTy> LazyBindingsMapTy; 332 LazyBindingsMapTy LazyBindingsMap; 333 334 public: 335 RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f) 336 : StoreManager(mgr), Features(f), 337 RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()) {} 338 339 340 /// setImplicitDefaultValue - Set the default binding for the provided 341 /// MemRegion to the value implicitly defined for compound literals when 342 /// the value is not specified. 343 RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B, 344 const MemRegion *R, QualType T); 345 346 /// ArrayToPointer - Emulates the "decay" of an array to a pointer 347 /// type. 'Array' represents the lvalue of the array being decayed 348 /// to a pointer, and the returned SVal represents the decayed 349 /// version of that lvalue (i.e., a pointer to the first element of 350 /// the array). This is called by ExprEngine when evaluating 351 /// casts from arrays to pointers. 352 SVal ArrayToPointer(Loc Array); 353 354 StoreRef getInitialStore(const LocationContext *InitLoc) { 355 return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this); 356 } 357 358 //===-------------------------------------------------------------------===// 359 // Binding values to regions. 360 //===-------------------------------------------------------------------===// 361 RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K, 362 const Expr *Ex, 363 unsigned Count, 364 const LocationContext *LCtx, 365 RegionBindingsRef B, 366 InvalidatedRegions *Invalidated); 367 368 StoreRef invalidateRegions(Store store, ArrayRef<const MemRegion *> Regions, 369 const Expr *E, unsigned Count, 370 const LocationContext *LCtx, 371 InvalidatedSymbols &IS, 372 const CallEvent *Call, 373 InvalidatedRegions *Invalidated); 374 375 bool scanReachableSymbols(Store S, const MemRegion *R, 376 ScanReachableSymbols &Callbacks); 377 378 RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B, 379 const SubRegion *R); 380 381 public: // Part of public interface to class. 382 383 virtual StoreRef Bind(Store store, Loc LV, SVal V) { 384 return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this); 385 } 386 387 RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V); 388 389 // BindDefault is only used to initialize a region with a default value. 390 StoreRef BindDefault(Store store, const MemRegion *R, SVal V) { 391 RegionBindingsRef B = getRegionBindings(store); 392 assert(!B.lookup(R, BindingKey::Default)); 393 assert(!B.lookup(R, BindingKey::Direct)); 394 return StoreRef(B.addBinding(R, BindingKey::Default, V) 395 .asImmutableMap() 396 .getRootWithoutRetain(), *this); 397 } 398 399 /// \brief Create a new store that binds a value to a compound literal. 400 /// 401 /// \param ST The original store whose bindings are the basis for the new 402 /// store. 403 /// 404 /// \param CL The compound literal to bind (the binding key). 405 /// 406 /// \param LC The LocationContext for the binding. 407 /// 408 /// \param V The value to bind to the compound literal. 409 StoreRef bindCompoundLiteral(Store ST, 410 const CompoundLiteralExpr *CL, 411 const LocationContext *LC, SVal V); 412 413 /// BindStruct - Bind a compound value to a structure. 414 RegionBindingsRef bindStruct(RegionBindingsConstRef B, 415 const TypedValueRegion* R, SVal V); 416 417 /// BindVector - Bind a compound value to a vector. 418 RegionBindingsRef bindVector(RegionBindingsConstRef B, 419 const TypedValueRegion* R, SVal V); 420 421 RegionBindingsRef bindArray(RegionBindingsConstRef B, 422 const TypedValueRegion* R, 423 SVal V); 424 425 /// Clears out all bindings in the given region and assigns a new value 426 /// as a Default binding. 427 RegionBindingsRef bindAggregate(RegionBindingsConstRef B, 428 const TypedRegion *R, 429 SVal DefaultVal); 430 431 /// \brief Create a new store with the specified binding removed. 432 /// \param ST the original store, that is the basis for the new store. 433 /// \param L the location whose binding should be removed. 434 virtual StoreRef killBinding(Store ST, Loc L); 435 436 void incrementReferenceCount(Store store) { 437 getRegionBindings(store).manualRetain(); 438 } 439 440 /// If the StoreManager supports it, decrement the reference count of 441 /// the specified Store object. If the reference count hits 0, the memory 442 /// associated with the object is recycled. 443 void decrementReferenceCount(Store store) { 444 getRegionBindings(store).manualRelease(); 445 } 446 447 bool includedInBindings(Store store, const MemRegion *region) const; 448 449 /// \brief Return the value bound to specified location in a given state. 450 /// 451 /// The high level logic for this method is this: 452 /// getBinding (L) 453 /// if L has binding 454 /// return L's binding 455 /// else if L is in killset 456 /// return unknown 457 /// else 458 /// if L is on stack or heap 459 /// return undefined 460 /// else 461 /// return symbolic 462 virtual SVal getBinding(Store S, Loc L, QualType T) { 463 return getBinding(getRegionBindings(S), L, T); 464 } 465 466 SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType()); 467 468 SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R); 469 470 SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R); 471 472 SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R); 473 474 SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R); 475 476 SVal getBindingForLazySymbol(const TypedValueRegion *R); 477 478 SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 479 const TypedValueRegion *R, 480 QualType Ty, 481 const MemRegion *superR); 482 483 SVal getLazyBinding(const SubRegion *LazyBindingRegion, 484 RegionBindingsRef LazyBinding); 485 486 /// Get bindings for the values in a struct and return a CompoundVal, used 487 /// when doing struct copy: 488 /// struct s x, y; 489 /// x = y; 490 /// y's value is retrieved by this method. 491 SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R); 492 SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R); 493 NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R); 494 495 /// Used to lazily generate derived symbols for bindings that are defined 496 /// implicitly by default bindings in a super region. 497 /// 498 /// Note that callers may need to specially handle LazyCompoundVals, which 499 /// are returned as is in case the caller needs to treat them differently. 500 Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 501 const MemRegion *superR, 502 const TypedValueRegion *R, 503 QualType Ty); 504 505 /// Get the state and region whose binding this region \p R corresponds to. 506 /// 507 /// If there is no lazy binding for \p R, the returned value will have a null 508 /// \c second. Note that a null pointer can represents a valid Store. 509 std::pair<Store, const SubRegion *> 510 findLazyBinding(RegionBindingsConstRef B, const SubRegion *R, 511 const SubRegion *originalRegion); 512 513 /// Returns the cached set of interesting SVals contained within a lazy 514 /// binding. 515 /// 516 /// The precise value of "interesting" is determined for the purposes of 517 /// RegionStore's internal analysis. It must always contain all regions and 518 /// symbols, but may omit constants and other kinds of SVal. 519 const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV); 520 521 //===------------------------------------------------------------------===// 522 // State pruning. 523 //===------------------------------------------------------------------===// 524 525 /// removeDeadBindings - Scans the RegionStore of 'state' for dead values. 526 /// It returns a new Store with these values removed. 527 StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, 528 SymbolReaper& SymReaper); 529 530 //===------------------------------------------------------------------===// 531 // Region "extents". 532 //===------------------------------------------------------------------===// 533 534 // FIXME: This method will soon be eliminated; see the note in Store.h. 535 DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state, 536 const MemRegion* R, QualType EleTy); 537 538 //===------------------------------------------------------------------===// 539 // Utility methods. 540 //===------------------------------------------------------------------===// 541 542 RegionBindingsRef getRegionBindings(Store store) const { 543 return RegionBindingsRef(CBFactory, 544 static_cast<const RegionBindings::TreeTy*>(store), 545 RBFactory.getTreeFactory()); 546 } 547 548 void print(Store store, raw_ostream &Out, const char* nl, 549 const char *sep); 550 551 void iterBindings(Store store, BindingsHandler& f) { 552 RegionBindingsRef B = getRegionBindings(store); 553 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 554 const ClusterBindings &Cluster = I.getData(); 555 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 556 CI != CE; ++CI) { 557 const BindingKey &K = CI.getKey(); 558 if (!K.isDirect()) 559 continue; 560 if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) { 561 // FIXME: Possibly incorporate the offset? 562 if (!f.HandleBinding(*this, store, R, CI.getData())) 563 return; 564 } 565 } 566 } 567 } 568 }; 569 570 } // end anonymous namespace 571 572 //===----------------------------------------------------------------------===// 573 // RegionStore creation. 574 //===----------------------------------------------------------------------===// 575 576 StoreManager *ento::CreateRegionStoreManager(ProgramStateManager& StMgr) { 577 RegionStoreFeatures F = maximal_features_tag(); 578 return new RegionStoreManager(StMgr, F); 579 } 580 581 StoreManager * 582 ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) { 583 RegionStoreFeatures F = minimal_features_tag(); 584 F.enableFields(true); 585 return new RegionStoreManager(StMgr, F); 586 } 587 588 589 //===----------------------------------------------------------------------===// 590 // Region Cluster analysis. 591 //===----------------------------------------------------------------------===// 592 593 namespace { 594 template <typename DERIVED> 595 class ClusterAnalysis { 596 protected: 597 typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap; 598 typedef SmallVector<const MemRegion *, 10> WorkList; 599 600 llvm::SmallPtrSet<const ClusterBindings *, 16> Visited; 601 602 WorkList WL; 603 604 RegionStoreManager &RM; 605 ASTContext &Ctx; 606 SValBuilder &svalBuilder; 607 608 RegionBindingsRef B; 609 610 const bool includeGlobals; 611 612 const ClusterBindings *getCluster(const MemRegion *R) { 613 return B.lookup(R); 614 } 615 616 public: 617 ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr, 618 RegionBindingsRef b, const bool includeGlobals) 619 : RM(rm), Ctx(StateMgr.getContext()), 620 svalBuilder(StateMgr.getSValBuilder()), 621 B(b), includeGlobals(includeGlobals) {} 622 623 RegionBindingsRef getRegionBindings() const { return B; } 624 625 bool isVisited(const MemRegion *R) { 626 return Visited.count(getCluster(R)); 627 } 628 629 void GenerateClusters() { 630 // Scan the entire set of bindings and record the region clusters. 631 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); 632 RI != RE; ++RI){ 633 const MemRegion *Base = RI.getKey(); 634 635 const ClusterBindings &Cluster = RI.getData(); 636 assert(!Cluster.isEmpty() && "Empty clusters should be removed"); 637 static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster); 638 639 if (includeGlobals) 640 if (isa<NonStaticGlobalSpaceRegion>(Base->getMemorySpace())) 641 AddToWorkList(Base, &Cluster); 642 } 643 } 644 645 bool AddToWorkList(const MemRegion *R, const ClusterBindings *C) { 646 if (C && !Visited.insert(C)) 647 return false; 648 WL.push_back(R); 649 return true; 650 } 651 652 bool AddToWorkList(const MemRegion *R) { 653 const MemRegion *baseR = R->getBaseRegion(); 654 return AddToWorkList(baseR, getCluster(baseR)); 655 } 656 657 void RunWorkList() { 658 while (!WL.empty()) { 659 const MemRegion *baseR = WL.pop_back_val(); 660 661 // First visit the cluster. 662 if (const ClusterBindings *Cluster = getCluster(baseR)) 663 static_cast<DERIVED*>(this)->VisitCluster(baseR, *Cluster); 664 665 // Next, visit the base region. 666 static_cast<DERIVED*>(this)->VisitBaseRegion(baseR); 667 } 668 } 669 670 public: 671 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {} 672 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C) {} 673 void VisitBaseRegion(const MemRegion *baseR) {} 674 }; 675 } 676 677 //===----------------------------------------------------------------------===// 678 // Binding invalidation. 679 //===----------------------------------------------------------------------===// 680 681 bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R, 682 ScanReachableSymbols &Callbacks) { 683 assert(R == R->getBaseRegion() && "Should only be called for base regions"); 684 RegionBindingsRef B = getRegionBindings(S); 685 const ClusterBindings *Cluster = B.lookup(R); 686 687 if (!Cluster) 688 return true; 689 690 for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end(); 691 RI != RE; ++RI) { 692 if (!Callbacks.scan(RI.getData())) 693 return false; 694 } 695 696 return true; 697 } 698 699 static inline bool isUnionField(const FieldRegion *FR) { 700 return FR->getDecl()->getParent()->isUnion(); 701 } 702 703 typedef SmallVector<const FieldDecl *, 8> FieldVector; 704 705 void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) { 706 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 707 708 const MemRegion *Base = K.getConcreteOffsetRegion(); 709 const MemRegion *R = K.getRegion(); 710 711 while (R != Base) { 712 if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) 713 if (!isUnionField(FR)) 714 Fields.push_back(FR->getDecl()); 715 716 R = cast<SubRegion>(R)->getSuperRegion(); 717 } 718 } 719 720 static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) { 721 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 722 723 if (Fields.empty()) 724 return true; 725 726 FieldVector FieldsInBindingKey; 727 getSymbolicOffsetFields(K, FieldsInBindingKey); 728 729 ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size(); 730 if (Delta >= 0) 731 return std::equal(FieldsInBindingKey.begin() + Delta, 732 FieldsInBindingKey.end(), 733 Fields.begin()); 734 else 735 return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(), 736 Fields.begin() - Delta); 737 } 738 739 /// Collects all bindings in \p Cluster that may refer to bindings within 740 /// \p Top. 741 /// 742 /// Each binding is a pair whose \c first is the key (a BindingKey) and whose 743 /// \c second is the value (an SVal). 744 /// 745 /// The \p IncludeAllDefaultBindings parameter specifies whether to include 746 /// default bindings that may extend beyond \p Top itself, e.g. if \p Top is 747 /// an aggregate within a larger aggregate with a default binding. 748 static void 749 collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 750 SValBuilder &SVB, const ClusterBindings &Cluster, 751 const SubRegion *Top, BindingKey TopKey, 752 bool IncludeAllDefaultBindings) { 753 FieldVector FieldsInSymbolicSubregions; 754 if (TopKey.hasSymbolicOffset()) { 755 getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions); 756 Top = cast<SubRegion>(TopKey.getConcreteOffsetRegion()); 757 TopKey = BindingKey::Make(Top, BindingKey::Default); 758 } 759 760 // Find the length (in bits) of the region being invalidated. 761 uint64_t Length = UINT64_MAX; 762 SVal Extent = Top->getExtent(SVB); 763 if (Optional<nonloc::ConcreteInt> ExtentCI = 764 Extent.getAs<nonloc::ConcreteInt>()) { 765 const llvm::APSInt &ExtentInt = ExtentCI->getValue(); 766 assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned()); 767 // Extents are in bytes but region offsets are in bits. Be careful! 768 Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth(); 769 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) { 770 if (FR->getDecl()->isBitField()) 771 Length = FR->getDecl()->getBitWidthValue(SVB.getContext()); 772 } 773 774 for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end(); 775 I != E; ++I) { 776 BindingKey NextKey = I.getKey(); 777 if (NextKey.getRegion() == TopKey.getRegion()) { 778 // FIXME: This doesn't catch the case where we're really invalidating a 779 // region with a symbolic offset. Example: 780 // R: points[i].y 781 // Next: points[0].x 782 783 if (NextKey.getOffset() > TopKey.getOffset() && 784 NextKey.getOffset() - TopKey.getOffset() < Length) { 785 // Case 1: The next binding is inside the region we're invalidating. 786 // Include it. 787 Bindings.push_back(*I); 788 789 } else if (NextKey.getOffset() == TopKey.getOffset()) { 790 // Case 2: The next binding is at the same offset as the region we're 791 // invalidating. In this case, we need to leave default bindings alone, 792 // since they may be providing a default value for a regions beyond what 793 // we're invalidating. 794 // FIXME: This is probably incorrect; consider invalidating an outer 795 // struct whose first field is bound to a LazyCompoundVal. 796 if (IncludeAllDefaultBindings || NextKey.isDirect()) 797 Bindings.push_back(*I); 798 } 799 800 } else if (NextKey.hasSymbolicOffset()) { 801 const MemRegion *Base = NextKey.getConcreteOffsetRegion(); 802 if (Top->isSubRegionOf(Base)) { 803 // Case 3: The next key is symbolic and we just changed something within 804 // its concrete region. We don't know if the binding is still valid, so 805 // we'll be conservative and include it. 806 if (IncludeAllDefaultBindings || NextKey.isDirect()) 807 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 808 Bindings.push_back(*I); 809 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) { 810 // Case 4: The next key is symbolic, but we changed a known 811 // super-region. In this case the binding is certainly included. 812 if (Top == Base || BaseSR->isSubRegionOf(Top)) 813 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 814 Bindings.push_back(*I); 815 } 816 } 817 } 818 } 819 820 static void 821 collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 822 SValBuilder &SVB, const ClusterBindings &Cluster, 823 const SubRegion *Top, bool IncludeAllDefaultBindings) { 824 collectSubRegionBindings(Bindings, SVB, Cluster, Top, 825 BindingKey::Make(Top, BindingKey::Default), 826 IncludeAllDefaultBindings); 827 } 828 829 RegionBindingsRef 830 RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B, 831 const SubRegion *Top) { 832 BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default); 833 const MemRegion *ClusterHead = TopKey.getBaseRegion(); 834 if (Top == ClusterHead) { 835 // We can remove an entire cluster's bindings all in one go. 836 return B.remove(Top); 837 } 838 839 const ClusterBindings *Cluster = B.lookup(ClusterHead); 840 if (!Cluster) 841 return B; 842 843 SmallVector<BindingPair, 32> Bindings; 844 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey, 845 /*IncludeAllDefaultBindings=*/false); 846 847 ClusterBindingsRef Result(*Cluster, CBFactory); 848 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 849 E = Bindings.end(); 850 I != E; ++I) 851 Result = Result.remove(I->first); 852 853 // If we're invalidating a region with a symbolic offset, we need to make sure 854 // we don't treat the base region as uninitialized anymore. 855 // FIXME: This isn't very precise; see the example in the loop. 856 if (TopKey.hasSymbolicOffset()) { 857 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 858 Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default), 859 UnknownVal()); 860 } 861 862 if (Result.isEmpty()) 863 return B.remove(ClusterHead); 864 return B.add(ClusterHead, Result.asImmutableMap()); 865 } 866 867 namespace { 868 class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker> 869 { 870 const Expr *Ex; 871 unsigned Count; 872 const LocationContext *LCtx; 873 InvalidatedSymbols &IS; 874 StoreManager::InvalidatedRegions *Regions; 875 public: 876 invalidateRegionsWorker(RegionStoreManager &rm, 877 ProgramStateManager &stateMgr, 878 RegionBindingsRef b, 879 const Expr *ex, unsigned count, 880 const LocationContext *lctx, 881 InvalidatedSymbols &is, 882 StoreManager::InvalidatedRegions *r, 883 bool includeGlobals) 884 : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, includeGlobals), 885 Ex(ex), Count(count), LCtx(lctx), IS(is), Regions(r) {} 886 887 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C); 888 void VisitBaseRegion(const MemRegion *baseR); 889 890 private: 891 void VisitBinding(SVal V); 892 }; 893 } 894 895 void invalidateRegionsWorker::VisitBinding(SVal V) { 896 // A symbol? Mark it touched by the invalidation. 897 if (SymbolRef Sym = V.getAsSymbol()) 898 IS.insert(Sym); 899 900 if (const MemRegion *R = V.getAsRegion()) { 901 AddToWorkList(R); 902 return; 903 } 904 905 // Is it a LazyCompoundVal? All references get invalidated as well. 906 if (Optional<nonloc::LazyCompoundVal> LCS = 907 V.getAs<nonloc::LazyCompoundVal>()) { 908 909 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 910 911 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 912 E = Vals.end(); 913 I != E; ++I) 914 VisitBinding(*I); 915 916 return; 917 } 918 } 919 920 void invalidateRegionsWorker::VisitCluster(const MemRegion *BaseR, 921 const ClusterBindings &C) { 922 for (ClusterBindings::iterator I = C.begin(), E = C.end(); I != E; ++I) 923 VisitBinding(I.getData()); 924 925 B = B.remove(BaseR); 926 } 927 928 void invalidateRegionsWorker::VisitBaseRegion(const MemRegion *baseR) { 929 // Symbolic region? Mark that symbol touched by the invalidation. 930 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) 931 IS.insert(SR->getSymbol()); 932 933 // BlockDataRegion? If so, invalidate captured variables that are passed 934 // by reference. 935 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) { 936 for (BlockDataRegion::referenced_vars_iterator 937 BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ; 938 BI != BE; ++BI) { 939 const VarRegion *VR = BI.getCapturedRegion(); 940 const VarDecl *VD = VR->getDecl(); 941 if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage()) { 942 AddToWorkList(VR); 943 } 944 else if (Loc::isLocType(VR->getValueType())) { 945 // Map the current bindings to a Store to retrieve the value 946 // of the binding. If that binding itself is a region, we should 947 // invalidate that region. This is because a block may capture 948 // a pointer value, but the thing pointed by that pointer may 949 // get invalidated. 950 SVal V = RM.getBinding(B, loc::MemRegionVal(VR)); 951 if (Optional<Loc> L = V.getAs<Loc>()) { 952 if (const MemRegion *LR = L->getAsRegion()) 953 AddToWorkList(LR); 954 } 955 } 956 } 957 return; 958 } 959 960 // Otherwise, we have a normal data region. Record that we touched the region. 961 if (Regions) 962 Regions->push_back(baseR); 963 964 if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) { 965 // Invalidate the region by setting its default value to 966 // conjured symbol. The type of the symbol is irrelavant. 967 DefinedOrUnknownSVal V = 968 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count); 969 B = B.addBinding(baseR, BindingKey::Default, V); 970 return; 971 } 972 973 if (!baseR->isBoundable()) 974 return; 975 976 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR); 977 QualType T = TR->getValueType(); 978 979 // Invalidate the binding. 980 if (T->isStructureOrClassType()) { 981 // Invalidate the region by setting its default value to 982 // conjured symbol. The type of the symbol is irrelavant. 983 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 984 Ctx.IntTy, Count); 985 B = B.addBinding(baseR, BindingKey::Default, V); 986 return; 987 } 988 989 if (const ArrayType *AT = Ctx.getAsArrayType(T)) { 990 // Set the default value of the array to conjured symbol. 991 DefinedOrUnknownSVal V = 992 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 993 AT->getElementType(), Count); 994 B = B.addBinding(baseR, BindingKey::Default, V); 995 return; 996 } 997 998 if (includeGlobals && 999 isa<NonStaticGlobalSpaceRegion>(baseR->getMemorySpace())) { 1000 // If the region is a global and we are invalidating all globals, 1001 // just erase the entry. This causes all globals to be lazily 1002 // symbolicated from the same base symbol. 1003 B = B.removeBinding(baseR); 1004 return; 1005 } 1006 1007 1008 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1009 T,Count); 1010 assert(SymbolManager::canSymbolicate(T) || V.isUnknown()); 1011 B = B.addBinding(baseR, BindingKey::Direct, V); 1012 } 1013 1014 RegionBindingsRef 1015 RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K, 1016 const Expr *Ex, 1017 unsigned Count, 1018 const LocationContext *LCtx, 1019 RegionBindingsRef B, 1020 InvalidatedRegions *Invalidated) { 1021 // Bind the globals memory space to a new symbol that we will use to derive 1022 // the bindings for all globals. 1023 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K); 1024 SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx, 1025 /* type does not matter */ Ctx.IntTy, 1026 Count); 1027 1028 B = B.removeBinding(GS) 1029 .addBinding(BindingKey::Make(GS, BindingKey::Default), V); 1030 1031 // Even if there are no bindings in the global scope, we still need to 1032 // record that we touched it. 1033 if (Invalidated) 1034 Invalidated->push_back(GS); 1035 1036 return B; 1037 } 1038 1039 StoreRef 1040 RegionStoreManager::invalidateRegions(Store store, 1041 ArrayRef<const MemRegion *> Regions, 1042 const Expr *Ex, unsigned Count, 1043 const LocationContext *LCtx, 1044 InvalidatedSymbols &IS, 1045 const CallEvent *Call, 1046 InvalidatedRegions *Invalidated) { 1047 invalidateRegionsWorker W(*this, StateMgr, 1048 RegionStoreManager::getRegionBindings(store), 1049 Ex, Count, LCtx, IS, Invalidated, false); 1050 1051 // Scan the bindings and generate the clusters. 1052 W.GenerateClusters(); 1053 1054 // Add the regions to the worklist. 1055 for (ArrayRef<const MemRegion *>::iterator 1056 I = Regions.begin(), E = Regions.end(); I != E; ++I) 1057 W.AddToWorkList(*I); 1058 1059 W.RunWorkList(); 1060 1061 // Return the new bindings. 1062 RegionBindingsRef B = W.getRegionBindings(); 1063 1064 // For all globals which are not static nor immutable: determine which global 1065 // regions should be invalidated and invalidate them. 1066 // TODO: This could possibly be more precise with modules. 1067 // 1068 // System calls invalidate only system globals. 1069 if (Call && Call->isInSystemHeader()) { 1070 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1071 Ex, Count, LCtx, B, Invalidated); 1072 // Internal calls might invalidate both system and internal globals. 1073 } else { 1074 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1075 Ex, Count, LCtx, B, Invalidated); 1076 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind, 1077 Ex, Count, LCtx, B, Invalidated); 1078 } 1079 1080 return StoreRef(B.asStore(), *this); 1081 } 1082 1083 //===----------------------------------------------------------------------===// 1084 // Extents for regions. 1085 //===----------------------------------------------------------------------===// 1086 1087 DefinedOrUnknownSVal 1088 RegionStoreManager::getSizeInElements(ProgramStateRef state, 1089 const MemRegion *R, 1090 QualType EleTy) { 1091 SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder); 1092 const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size); 1093 if (!SizeInt) 1094 return UnknownVal(); 1095 1096 CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue()); 1097 1098 if (Ctx.getAsVariableArrayType(EleTy)) { 1099 // FIXME: We need to track extra state to properly record the size 1100 // of VLAs. Returning UnknownVal here, however, is a stop-gap so that 1101 // we don't have a divide-by-zero below. 1102 return UnknownVal(); 1103 } 1104 1105 CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy); 1106 1107 // If a variable is reinterpreted as a type that doesn't fit into a larger 1108 // type evenly, round it down. 1109 // This is a signed value, since it's used in arithmetic with signed indices. 1110 return svalBuilder.makeIntVal(RegionSize / EleSize, false); 1111 } 1112 1113 //===----------------------------------------------------------------------===// 1114 // Location and region casting. 1115 //===----------------------------------------------------------------------===// 1116 1117 /// ArrayToPointer - Emulates the "decay" of an array to a pointer 1118 /// type. 'Array' represents the lvalue of the array being decayed 1119 /// to a pointer, and the returned SVal represents the decayed 1120 /// version of that lvalue (i.e., a pointer to the first element of 1121 /// the array). This is called by ExprEngine when evaluating casts 1122 /// from arrays to pointers. 1123 SVal RegionStoreManager::ArrayToPointer(Loc Array) { 1124 if (!Array.getAs<loc::MemRegionVal>()) 1125 return UnknownVal(); 1126 1127 const MemRegion* R = Array.castAs<loc::MemRegionVal>().getRegion(); 1128 const TypedValueRegion* ArrayR = dyn_cast<TypedValueRegion>(R); 1129 1130 if (!ArrayR) 1131 return UnknownVal(); 1132 1133 // Strip off typedefs from the ArrayRegion's ValueType. 1134 QualType T = ArrayR->getValueType().getDesugaredType(Ctx); 1135 const ArrayType *AT = cast<ArrayType>(T); 1136 T = AT->getElementType(); 1137 1138 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex(); 1139 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, ArrayR, Ctx)); 1140 } 1141 1142 //===----------------------------------------------------------------------===// 1143 // Loading values from regions. 1144 //===----------------------------------------------------------------------===// 1145 1146 SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) { 1147 assert(!L.getAs<UnknownVal>() && "location unknown"); 1148 assert(!L.getAs<UndefinedVal>() && "location undefined"); 1149 1150 // For access to concrete addresses, return UnknownVal. Checks 1151 // for null dereferences (and similar errors) are done by checkers, not 1152 // the Store. 1153 // FIXME: We can consider lazily symbolicating such memory, but we really 1154 // should defer this when we can reason easily about symbolicating arrays 1155 // of bytes. 1156 if (L.getAs<loc::ConcreteInt>()) { 1157 return UnknownVal(); 1158 } 1159 if (!L.getAs<loc::MemRegionVal>()) { 1160 return UnknownVal(); 1161 } 1162 1163 const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion(); 1164 1165 if (isa<AllocaRegion>(MR) || 1166 isa<SymbolicRegion>(MR) || 1167 isa<CodeTextRegion>(MR)) { 1168 if (T.isNull()) { 1169 if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR)) 1170 T = TR->getLocationType(); 1171 else { 1172 const SymbolicRegion *SR = cast<SymbolicRegion>(MR); 1173 T = SR->getSymbol()->getType(); 1174 } 1175 } 1176 MR = GetElementZeroRegion(MR, T); 1177 } 1178 1179 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument 1180 // instead of 'Loc', and have the other Loc cases handled at a higher level. 1181 const TypedValueRegion *R = cast<TypedValueRegion>(MR); 1182 QualType RTy = R->getValueType(); 1183 1184 // FIXME: we do not yet model the parts of a complex type, so treat the 1185 // whole thing as "unknown". 1186 if (RTy->isAnyComplexType()) 1187 return UnknownVal(); 1188 1189 // FIXME: We should eventually handle funny addressing. e.g.: 1190 // 1191 // int x = ...; 1192 // int *p = &x; 1193 // char *q = (char*) p; 1194 // char c = *q; // returns the first byte of 'x'. 1195 // 1196 // Such funny addressing will occur due to layering of regions. 1197 if (RTy->isStructureOrClassType()) 1198 return getBindingForStruct(B, R); 1199 1200 // FIXME: Handle unions. 1201 if (RTy->isUnionType()) 1202 return UnknownVal(); 1203 1204 if (RTy->isArrayType()) { 1205 if (RTy->isConstantArrayType()) 1206 return getBindingForArray(B, R); 1207 else 1208 return UnknownVal(); 1209 } 1210 1211 // FIXME: handle Vector types. 1212 if (RTy->isVectorType()) 1213 return UnknownVal(); 1214 1215 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R)) 1216 return CastRetrievedVal(getBindingForField(B, FR), FR, T, false); 1217 1218 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) { 1219 // FIXME: Here we actually perform an implicit conversion from the loaded 1220 // value to the element type. Eventually we want to compose these values 1221 // more intelligently. For example, an 'element' can encompass multiple 1222 // bound regions (e.g., several bound bytes), or could be a subset of 1223 // a larger value. 1224 return CastRetrievedVal(getBindingForElement(B, ER), ER, T, false); 1225 } 1226 1227 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) { 1228 // FIXME: Here we actually perform an implicit conversion from the loaded 1229 // value to the ivar type. What we should model is stores to ivars 1230 // that blow past the extent of the ivar. If the address of the ivar is 1231 // reinterpretted, it is possible we stored a different value that could 1232 // fit within the ivar. Either we need to cast these when storing them 1233 // or reinterpret them lazily (as we do here). 1234 return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T, false); 1235 } 1236 1237 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { 1238 // FIXME: Here we actually perform an implicit conversion from the loaded 1239 // value to the variable type. What we should model is stores to variables 1240 // that blow past the extent of the variable. If the address of the 1241 // variable is reinterpretted, it is possible we stored a different value 1242 // that could fit within the variable. Either we need to cast these when 1243 // storing them or reinterpret them lazily (as we do here). 1244 return CastRetrievedVal(getBindingForVar(B, VR), VR, T, false); 1245 } 1246 1247 const SVal *V = B.lookup(R, BindingKey::Direct); 1248 1249 // Check if the region has a binding. 1250 if (V) 1251 return *V; 1252 1253 // The location does not have a bound value. This means that it has 1254 // the value it had upon its creation and/or entry to the analyzed 1255 // function/method. These are either symbolic values or 'undefined'. 1256 if (R->hasStackNonParametersStorage()) { 1257 // All stack variables are considered to have undefined values 1258 // upon creation. All heap allocated blocks are considered to 1259 // have undefined values as well unless they are explicitly bound 1260 // to specific values. 1261 return UndefinedVal(); 1262 } 1263 1264 // All other values are symbolic. 1265 return svalBuilder.getRegionValueSymbolVal(R); 1266 } 1267 1268 /// Checks to see if store \p B has a lazy binding for region \p R. 1269 /// 1270 /// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected 1271 /// if there are additional bindings within \p R. 1272 /// 1273 /// Note that unlike RegionStoreManager::findLazyBinding, this will not search 1274 /// for lazy bindings for super-regions of \p R. 1275 static Optional<nonloc::LazyCompoundVal> 1276 getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B, 1277 const SubRegion *R, bool AllowSubregionBindings) { 1278 Optional<SVal> V = B.getDefaultBinding(R); 1279 if (!V) 1280 return None; 1281 1282 Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>(); 1283 if (!LCV) 1284 return None; 1285 1286 // If the LCV is for a subregion, the types won't match, and we shouldn't 1287 // reuse the binding. Unfortuately we can only check this if the destination 1288 // region is a TypedValueRegion. 1289 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) { 1290 QualType RegionTy = TVR->getValueType(); 1291 QualType SourceRegionTy = LCV->getRegion()->getValueType(); 1292 if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy)) 1293 return None; 1294 } 1295 1296 if (!AllowSubregionBindings) { 1297 // If there are any other bindings within this region, we shouldn't reuse 1298 // the top-level binding. 1299 SmallVector<BindingPair, 16> Bindings; 1300 collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R, 1301 /*IncludeAllDefaultBindings=*/true); 1302 if (Bindings.size() > 1) 1303 return None; 1304 } 1305 1306 return *LCV; 1307 } 1308 1309 1310 std::pair<Store, const SubRegion *> 1311 RegionStoreManager::findLazyBinding(RegionBindingsConstRef B, 1312 const SubRegion *R, 1313 const SubRegion *originalRegion) { 1314 if (originalRegion != R) { 1315 if (Optional<nonloc::LazyCompoundVal> V = 1316 getExistingLazyBinding(svalBuilder, B, R, true)) 1317 return std::make_pair(V->getStore(), V->getRegion()); 1318 } 1319 1320 typedef std::pair<Store, const SubRegion *> StoreRegionPair; 1321 StoreRegionPair Result = StoreRegionPair(); 1322 1323 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 1324 Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()), 1325 originalRegion); 1326 1327 if (Result.second) 1328 Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second); 1329 1330 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) { 1331 Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()), 1332 originalRegion); 1333 1334 if (Result.second) 1335 Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second); 1336 1337 } else if (const CXXBaseObjectRegion *BaseReg = 1338 dyn_cast<CXXBaseObjectRegion>(R)) { 1339 // C++ base object region is another kind of region that we should blast 1340 // through to look for lazy compound value. It is like a field region. 1341 Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()), 1342 originalRegion); 1343 1344 if (Result.second) 1345 Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg, 1346 Result.second); 1347 } 1348 1349 return Result; 1350 } 1351 1352 SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B, 1353 const ElementRegion* R) { 1354 // We do not currently model bindings of the CompoundLiteralregion. 1355 if (isa<CompoundLiteralRegion>(R->getBaseRegion())) 1356 return UnknownVal(); 1357 1358 // Check if the region has a binding. 1359 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1360 return *V; 1361 1362 const MemRegion* superR = R->getSuperRegion(); 1363 1364 // Check if the region is an element region of a string literal. 1365 if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) { 1366 // FIXME: Handle loads from strings where the literal is treated as 1367 // an integer, e.g., *((unsigned int*)"hello") 1368 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType(); 1369 if (T != Ctx.getCanonicalType(R->getElementType())) 1370 return UnknownVal(); 1371 1372 const StringLiteral *Str = StrR->getStringLiteral(); 1373 SVal Idx = R->getIndex(); 1374 if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) { 1375 int64_t i = CI->getValue().getSExtValue(); 1376 // Abort on string underrun. This can be possible by arbitrary 1377 // clients of getBindingForElement(). 1378 if (i < 0) 1379 return UndefinedVal(); 1380 int64_t length = Str->getLength(); 1381 // Technically, only i == length is guaranteed to be null. 1382 // However, such overflows should be caught before reaching this point; 1383 // the only time such an access would be made is if a string literal was 1384 // used to initialize a larger array. 1385 char c = (i >= length) ? '\0' : Str->getCodeUnit(i); 1386 return svalBuilder.makeIntVal(c, T); 1387 } 1388 } 1389 1390 // Check for loads from a code text region. For such loads, just give up. 1391 if (isa<CodeTextRegion>(superR)) 1392 return UnknownVal(); 1393 1394 // Handle the case where we are indexing into a larger scalar object. 1395 // For example, this handles: 1396 // int x = ... 1397 // char *y = &x; 1398 // return *y; 1399 // FIXME: This is a hack, and doesn't do anything really intelligent yet. 1400 const RegionRawOffset &O = R->getAsArrayOffset(); 1401 1402 // If we cannot reason about the offset, return an unknown value. 1403 if (!O.getRegion()) 1404 return UnknownVal(); 1405 1406 if (const TypedValueRegion *baseR = 1407 dyn_cast_or_null<TypedValueRegion>(O.getRegion())) { 1408 QualType baseT = baseR->getValueType(); 1409 if (baseT->isScalarType()) { 1410 QualType elemT = R->getElementType(); 1411 if (elemT->isScalarType()) { 1412 if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) { 1413 if (const Optional<SVal> &V = B.getDirectBinding(superR)) { 1414 if (SymbolRef parentSym = V->getAsSymbol()) 1415 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1416 1417 if (V->isUnknownOrUndef()) 1418 return *V; 1419 // Other cases: give up. We are indexing into a larger object 1420 // that has some value, but we don't know how to handle that yet. 1421 return UnknownVal(); 1422 } 1423 } 1424 } 1425 } 1426 } 1427 return getBindingForFieldOrElementCommon(B, R, R->getElementType(), 1428 superR); 1429 } 1430 1431 SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B, 1432 const FieldRegion* R) { 1433 1434 // Check if the region has a binding. 1435 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1436 return *V; 1437 1438 QualType Ty = R->getValueType(); 1439 return getBindingForFieldOrElementCommon(B, R, Ty, R->getSuperRegion()); 1440 } 1441 1442 Optional<SVal> 1443 RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 1444 const MemRegion *superR, 1445 const TypedValueRegion *R, 1446 QualType Ty) { 1447 1448 if (const Optional<SVal> &D = B.getDefaultBinding(superR)) { 1449 const SVal &val = D.getValue(); 1450 if (SymbolRef parentSym = val.getAsSymbol()) 1451 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1452 1453 if (val.isZeroConstant()) 1454 return svalBuilder.makeZeroVal(Ty); 1455 1456 if (val.isUnknownOrUndef()) 1457 return val; 1458 1459 // Lazy bindings are usually handled through getExistingLazyBinding(). 1460 // We should unify these two code paths at some point. 1461 if (val.getAs<nonloc::LazyCompoundVal>()) 1462 return val; 1463 1464 llvm_unreachable("Unknown default value"); 1465 } 1466 1467 return None; 1468 } 1469 1470 SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion, 1471 RegionBindingsRef LazyBinding) { 1472 SVal Result; 1473 if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion)) 1474 Result = getBindingForElement(LazyBinding, ER); 1475 else 1476 Result = getBindingForField(LazyBinding, 1477 cast<FieldRegion>(LazyBindingRegion)); 1478 1479 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1480 // default value for /part/ of an aggregate from a default value for the 1481 // /entire/ aggregate. The most common case of this is when struct Outer 1482 // has as its first member a struct Inner, which is copied in from a stack 1483 // variable. In this case, even if the Outer's default value is symbolic, 0, 1484 // or unknown, it gets overridden by the Inner's default value of undefined. 1485 // 1486 // This is a general problem -- if the Inner is zero-initialized, the Outer 1487 // will now look zero-initialized. The proper way to solve this is with a 1488 // new version of RegionStore that tracks the extent of a binding as well 1489 // as the offset. 1490 // 1491 // This hack only takes care of the undefined case because that can very 1492 // quickly result in a warning. 1493 if (Result.isUndef()) 1494 Result = UnknownVal(); 1495 1496 return Result; 1497 } 1498 1499 SVal 1500 RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 1501 const TypedValueRegion *R, 1502 QualType Ty, 1503 const MemRegion *superR) { 1504 1505 // At this point we have already checked in either getBindingForElement or 1506 // getBindingForField if 'R' has a direct binding. 1507 1508 // Lazy binding? 1509 Store lazyBindingStore = NULL; 1510 const SubRegion *lazyBindingRegion = NULL; 1511 llvm::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R); 1512 if (lazyBindingRegion) 1513 return getLazyBinding(lazyBindingRegion, 1514 getRegionBindings(lazyBindingStore)); 1515 1516 // Record whether or not we see a symbolic index. That can completely 1517 // be out of scope of our lookup. 1518 bool hasSymbolicIndex = false; 1519 1520 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1521 // default value for /part/ of an aggregate from a default value for the 1522 // /entire/ aggregate. The most common case of this is when struct Outer 1523 // has as its first member a struct Inner, which is copied in from a stack 1524 // variable. In this case, even if the Outer's default value is symbolic, 0, 1525 // or unknown, it gets overridden by the Inner's default value of undefined. 1526 // 1527 // This is a general problem -- if the Inner is zero-initialized, the Outer 1528 // will now look zero-initialized. The proper way to solve this is with a 1529 // new version of RegionStore that tracks the extent of a binding as well 1530 // as the offset. 1531 // 1532 // This hack only takes care of the undefined case because that can very 1533 // quickly result in a warning. 1534 bool hasPartialLazyBinding = false; 1535 1536 const SubRegion *Base = dyn_cast<SubRegion>(superR); 1537 while (Base) { 1538 if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) { 1539 if (D->getAs<nonloc::LazyCompoundVal>()) { 1540 hasPartialLazyBinding = true; 1541 break; 1542 } 1543 1544 return *D; 1545 } 1546 1547 if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) { 1548 NonLoc index = ER->getIndex(); 1549 if (!index.isConstant()) 1550 hasSymbolicIndex = true; 1551 } 1552 1553 // If our super region is a field or element itself, walk up the region 1554 // hierarchy to see if there is a default value installed in an ancestor. 1555 Base = dyn_cast<SubRegion>(Base->getSuperRegion()); 1556 } 1557 1558 if (R->hasStackNonParametersStorage()) { 1559 if (isa<ElementRegion>(R)) { 1560 // Currently we don't reason specially about Clang-style vectors. Check 1561 // if superR is a vector and if so return Unknown. 1562 if (const TypedValueRegion *typedSuperR = 1563 dyn_cast<TypedValueRegion>(superR)) { 1564 if (typedSuperR->getValueType()->isVectorType()) 1565 return UnknownVal(); 1566 } 1567 } 1568 1569 // FIXME: We also need to take ElementRegions with symbolic indexes into 1570 // account. This case handles both directly accessing an ElementRegion 1571 // with a symbolic offset, but also fields within an element with 1572 // a symbolic offset. 1573 if (hasSymbolicIndex) 1574 return UnknownVal(); 1575 1576 if (!hasPartialLazyBinding) 1577 return UndefinedVal(); 1578 } 1579 1580 // All other values are symbolic. 1581 return svalBuilder.getRegionValueSymbolVal(R); 1582 } 1583 1584 SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B, 1585 const ObjCIvarRegion* R) { 1586 // Check if the region has a binding. 1587 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1588 return *V; 1589 1590 const MemRegion *superR = R->getSuperRegion(); 1591 1592 // Check if the super region has a default binding. 1593 if (const Optional<SVal> &V = B.getDefaultBinding(superR)) { 1594 if (SymbolRef parentSym = V->getAsSymbol()) 1595 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1596 1597 // Other cases: give up. 1598 return UnknownVal(); 1599 } 1600 1601 return getBindingForLazySymbol(R); 1602 } 1603 1604 static Optional<SVal> getConstValue(SValBuilder &SVB, const VarDecl *VD) { 1605 ASTContext &Ctx = SVB.getContext(); 1606 if (!VD->getType().isConstQualified()) 1607 return None; 1608 1609 const Expr *Init = VD->getInit(); 1610 if (!Init) 1611 return None; 1612 1613 llvm::APSInt Result; 1614 if (!Init->isGLValue() && Init->EvaluateAsInt(Result, Ctx)) 1615 return SVB.makeIntVal(Result); 1616 1617 if (Init->isNullPointerConstant(Ctx, Expr::NPC_ValueDependentIsNotNull)) 1618 return SVB.makeNull(); 1619 1620 // FIXME: Handle other possible constant expressions. 1621 return None; 1622 } 1623 1624 SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B, 1625 const VarRegion *R) { 1626 1627 // Check if the region has a binding. 1628 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1629 return *V; 1630 1631 // Lazily derive a value for the VarRegion. 1632 const VarDecl *VD = R->getDecl(); 1633 const MemSpaceRegion *MS = R->getMemorySpace(); 1634 1635 // Arguments are always symbolic. 1636 if (isa<StackArgumentsSpaceRegion>(MS)) 1637 return svalBuilder.getRegionValueSymbolVal(R); 1638 1639 // Is 'VD' declared constant? If so, retrieve the constant value. 1640 if (Optional<SVal> V = getConstValue(svalBuilder, VD)) 1641 return *V; 1642 1643 // This must come after the check for constants because closure-captured 1644 // constant variables may appear in UnknownSpaceRegion. 1645 if (isa<UnknownSpaceRegion>(MS)) 1646 return svalBuilder.getRegionValueSymbolVal(R); 1647 1648 if (isa<GlobalsSpaceRegion>(MS)) { 1649 QualType T = VD->getType(); 1650 1651 // Function-scoped static variables are default-initialized to 0; if they 1652 // have an initializer, it would have been processed by now. 1653 if (isa<StaticGlobalSpaceRegion>(MS)) 1654 return svalBuilder.makeZeroVal(T); 1655 1656 if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) { 1657 assert(!V->getAs<nonloc::LazyCompoundVal>()); 1658 return V.getValue(); 1659 } 1660 1661 return svalBuilder.getRegionValueSymbolVal(R); 1662 } 1663 1664 return UndefinedVal(); 1665 } 1666 1667 SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) { 1668 // All other values are symbolic. 1669 return svalBuilder.getRegionValueSymbolVal(R); 1670 } 1671 1672 const RegionStoreManager::SValListTy & 1673 RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) { 1674 // First, check the cache. 1675 LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData()); 1676 if (I != LazyBindingsMap.end()) 1677 return I->second; 1678 1679 // If we don't have a list of values cached, start constructing it. 1680 SValListTy List; 1681 1682 const SubRegion *LazyR = LCV.getRegion(); 1683 RegionBindingsRef B = getRegionBindings(LCV.getStore()); 1684 1685 // If this region had /no/ bindings at the time, there are no interesting 1686 // values to return. 1687 const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion()); 1688 if (!Cluster) 1689 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1690 1691 SmallVector<BindingPair, 32> Bindings; 1692 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR, 1693 /*IncludeAllDefaultBindings=*/true); 1694 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 1695 E = Bindings.end(); 1696 I != E; ++I) { 1697 SVal V = I->second; 1698 if (V.isUnknownOrUndef() || V.isConstant()) 1699 continue; 1700 1701 if (Optional<nonloc::LazyCompoundVal> InnerLCV = 1702 V.getAs<nonloc::LazyCompoundVal>()) { 1703 const SValListTy &InnerList = getInterestingValues(*InnerLCV); 1704 List.insert(List.end(), InnerList.begin(), InnerList.end()); 1705 continue; 1706 } 1707 1708 List.push_back(V); 1709 } 1710 1711 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1712 } 1713 1714 NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B, 1715 const TypedValueRegion *R) { 1716 if (Optional<nonloc::LazyCompoundVal> V = 1717 getExistingLazyBinding(svalBuilder, B, R, false)) 1718 return *V; 1719 1720 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R); 1721 } 1722 1723 SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B, 1724 const TypedValueRegion *R) { 1725 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl(); 1726 if (RD->field_empty()) 1727 return UnknownVal(); 1728 1729 return createLazyBinding(B, R); 1730 } 1731 1732 SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B, 1733 const TypedValueRegion *R) { 1734 assert(Ctx.getAsConstantArrayType(R->getValueType()) && 1735 "Only constant array types can have compound bindings."); 1736 1737 return createLazyBinding(B, R); 1738 } 1739 1740 bool RegionStoreManager::includedInBindings(Store store, 1741 const MemRegion *region) const { 1742 RegionBindingsRef B = getRegionBindings(store); 1743 region = region->getBaseRegion(); 1744 1745 // Quick path: if the base is the head of a cluster, the region is live. 1746 if (B.lookup(region)) 1747 return true; 1748 1749 // Slow path: if the region is the VALUE of any binding, it is live. 1750 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) { 1751 const ClusterBindings &Cluster = RI.getData(); 1752 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1753 CI != CE; ++CI) { 1754 const SVal &D = CI.getData(); 1755 if (const MemRegion *R = D.getAsRegion()) 1756 if (R->getBaseRegion() == region) 1757 return true; 1758 } 1759 } 1760 1761 return false; 1762 } 1763 1764 //===----------------------------------------------------------------------===// 1765 // Binding values to regions. 1766 //===----------------------------------------------------------------------===// 1767 1768 StoreRef RegionStoreManager::killBinding(Store ST, Loc L) { 1769 if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>()) 1770 if (const MemRegion* R = LV->getRegion()) 1771 return StoreRef(getRegionBindings(ST).removeBinding(R) 1772 .asImmutableMap() 1773 .getRootWithoutRetain(), 1774 *this); 1775 1776 return StoreRef(ST, *this); 1777 } 1778 1779 RegionBindingsRef 1780 RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) { 1781 if (L.getAs<loc::ConcreteInt>()) 1782 return B; 1783 1784 // If we get here, the location should be a region. 1785 const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion(); 1786 1787 // Check if the region is a struct region. 1788 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) { 1789 QualType Ty = TR->getValueType(); 1790 if (Ty->isArrayType()) 1791 return bindArray(B, TR, V); 1792 if (Ty->isStructureOrClassType()) 1793 return bindStruct(B, TR, V); 1794 if (Ty->isVectorType()) 1795 return bindVector(B, TR, V); 1796 } 1797 1798 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 1799 // Binding directly to a symbolic region should be treated as binding 1800 // to element 0. 1801 QualType T = SR->getSymbol()->getType(); 1802 if (T->isAnyPointerType() || T->isReferenceType()) 1803 T = T->getPointeeType(); 1804 1805 R = GetElementZeroRegion(SR, T); 1806 } 1807 1808 // Clear out bindings that may overlap with this binding. 1809 RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R)); 1810 return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V); 1811 } 1812 1813 // FIXME: this method should be merged into Bind(). 1814 StoreRef RegionStoreManager::bindCompoundLiteral(Store ST, 1815 const CompoundLiteralExpr *CL, 1816 const LocationContext *LC, 1817 SVal V) { 1818 return Bind(ST, loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)), V); 1819 } 1820 1821 RegionBindingsRef 1822 RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B, 1823 const MemRegion *R, 1824 QualType T) { 1825 SVal V; 1826 1827 if (Loc::isLocType(T)) 1828 V = svalBuilder.makeNull(); 1829 else if (T->isIntegerType()) 1830 V = svalBuilder.makeZeroVal(T); 1831 else if (T->isStructureOrClassType() || T->isArrayType()) { 1832 // Set the default value to a zero constant when it is a structure 1833 // or array. The type doesn't really matter. 1834 V = svalBuilder.makeZeroVal(Ctx.IntTy); 1835 } 1836 else { 1837 // We can't represent values of this type, but we still need to set a value 1838 // to record that the region has been initialized. 1839 // If this assertion ever fires, a new case should be added above -- we 1840 // should know how to default-initialize any value we can symbolicate. 1841 assert(!SymbolManager::canSymbolicate(T) && "This type is representable"); 1842 V = UnknownVal(); 1843 } 1844 1845 return B.addBinding(R, BindingKey::Default, V); 1846 } 1847 1848 RegionBindingsRef 1849 RegionStoreManager::bindArray(RegionBindingsConstRef B, 1850 const TypedValueRegion* R, 1851 SVal Init) { 1852 1853 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType())); 1854 QualType ElementTy = AT->getElementType(); 1855 Optional<uint64_t> Size; 1856 1857 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT)) 1858 Size = CAT->getSize().getZExtValue(); 1859 1860 // Check if the init expr is a string literal. 1861 if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) { 1862 const StringRegion *S = cast<StringRegion>(MRV->getRegion()); 1863 1864 // Treat the string as a lazy compound value. 1865 StoreRef store(B.asStore(), *this); 1866 nonloc::LazyCompoundVal LCV = svalBuilder.makeLazyCompoundVal(store, S) 1867 .castAs<nonloc::LazyCompoundVal>(); 1868 return bindAggregate(B, R, LCV); 1869 } 1870 1871 // Handle lazy compound values. 1872 if (Init.getAs<nonloc::LazyCompoundVal>()) 1873 return bindAggregate(B, R, Init); 1874 1875 // Remaining case: explicit compound values. 1876 1877 if (Init.isUnknown()) 1878 return setImplicitDefaultValue(B, R, ElementTy); 1879 1880 const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>(); 1881 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1882 uint64_t i = 0; 1883 1884 RegionBindingsRef NewB(B); 1885 1886 for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) { 1887 // The init list might be shorter than the array length. 1888 if (VI == VE) 1889 break; 1890 1891 const NonLoc &Idx = svalBuilder.makeArrayIndex(i); 1892 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx); 1893 1894 if (ElementTy->isStructureOrClassType()) 1895 NewB = bindStruct(NewB, ER, *VI); 1896 else if (ElementTy->isArrayType()) 1897 NewB = bindArray(NewB, ER, *VI); 1898 else 1899 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1900 } 1901 1902 // If the init list is shorter than the array length, set the 1903 // array default value. 1904 if (Size.hasValue() && i < Size.getValue()) 1905 NewB = setImplicitDefaultValue(NewB, R, ElementTy); 1906 1907 return NewB; 1908 } 1909 1910 RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B, 1911 const TypedValueRegion* R, 1912 SVal V) { 1913 QualType T = R->getValueType(); 1914 assert(T->isVectorType()); 1915 const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs. 1916 1917 // Handle lazy compound values and symbolic values. 1918 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 1919 return bindAggregate(B, R, V); 1920 1921 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1922 // that we are binding symbolic struct value. Kill the field values, and if 1923 // the value is symbolic go and bind it as a "default" binding. 1924 if (!V.getAs<nonloc::CompoundVal>()) { 1925 return bindAggregate(B, R, UnknownVal()); 1926 } 1927 1928 QualType ElemType = VT->getElementType(); 1929 nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>(); 1930 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1931 unsigned index = 0, numElements = VT->getNumElements(); 1932 RegionBindingsRef NewB(B); 1933 1934 for ( ; index != numElements ; ++index) { 1935 if (VI == VE) 1936 break; 1937 1938 NonLoc Idx = svalBuilder.makeArrayIndex(index); 1939 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx); 1940 1941 if (ElemType->isArrayType()) 1942 NewB = bindArray(NewB, ER, *VI); 1943 else if (ElemType->isStructureOrClassType()) 1944 NewB = bindStruct(NewB, ER, *VI); 1945 else 1946 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1947 } 1948 return NewB; 1949 } 1950 1951 RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B, 1952 const TypedValueRegion* R, 1953 SVal V) { 1954 if (!Features.supportsFields()) 1955 return B; 1956 1957 QualType T = R->getValueType(); 1958 assert(T->isStructureOrClassType()); 1959 1960 const RecordType* RT = T->getAs<RecordType>(); 1961 RecordDecl *RD = RT->getDecl(); 1962 1963 if (!RD->isCompleteDefinition()) 1964 return B; 1965 1966 // Handle lazy compound values and symbolic values. 1967 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 1968 return bindAggregate(B, R, V); 1969 1970 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1971 // that we are binding symbolic struct value. Kill the field values, and if 1972 // the value is symbolic go and bind it as a "default" binding. 1973 if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>()) 1974 return bindAggregate(B, R, UnknownVal()); 1975 1976 const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>(); 1977 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1978 1979 RecordDecl::field_iterator FI, FE; 1980 RegionBindingsRef NewB(B); 1981 1982 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) { 1983 1984 if (VI == VE) 1985 break; 1986 1987 // Skip any unnamed bitfields to stay in sync with the initializers. 1988 if (FI->isUnnamedBitfield()) 1989 continue; 1990 1991 QualType FTy = FI->getType(); 1992 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R); 1993 1994 if (FTy->isArrayType()) 1995 NewB = bindArray(NewB, FR, *VI); 1996 else if (FTy->isStructureOrClassType()) 1997 NewB = bindStruct(NewB, FR, *VI); 1998 else 1999 NewB = bind(NewB, svalBuilder.makeLoc(FR), *VI); 2000 ++VI; 2001 } 2002 2003 // There may be fewer values in the initialize list than the fields of struct. 2004 if (FI != FE) { 2005 NewB = NewB.addBinding(R, BindingKey::Default, 2006 svalBuilder.makeIntVal(0, false)); 2007 } 2008 2009 return NewB; 2010 } 2011 2012 RegionBindingsRef 2013 RegionStoreManager::bindAggregate(RegionBindingsConstRef B, 2014 const TypedRegion *R, 2015 SVal Val) { 2016 // Remove the old bindings, using 'R' as the root of all regions 2017 // we will invalidate. Then add the new binding. 2018 return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val); 2019 } 2020 2021 //===----------------------------------------------------------------------===// 2022 // State pruning. 2023 //===----------------------------------------------------------------------===// 2024 2025 namespace { 2026 class removeDeadBindingsWorker : 2027 public ClusterAnalysis<removeDeadBindingsWorker> { 2028 SmallVector<const SymbolicRegion*, 12> Postponed; 2029 SymbolReaper &SymReaper; 2030 const StackFrameContext *CurrentLCtx; 2031 2032 public: 2033 removeDeadBindingsWorker(RegionStoreManager &rm, 2034 ProgramStateManager &stateMgr, 2035 RegionBindingsRef b, SymbolReaper &symReaper, 2036 const StackFrameContext *LCtx) 2037 : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b, 2038 /* includeGlobals = */ false), 2039 SymReaper(symReaper), CurrentLCtx(LCtx) {} 2040 2041 // Called by ClusterAnalysis. 2042 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C); 2043 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C); 2044 2045 bool UpdatePostponed(); 2046 void VisitBinding(SVal V); 2047 }; 2048 } 2049 2050 void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR, 2051 const ClusterBindings &C) { 2052 2053 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) { 2054 if (SymReaper.isLive(VR)) 2055 AddToWorkList(baseR, &C); 2056 2057 return; 2058 } 2059 2060 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 2061 if (SymReaper.isLive(SR->getSymbol())) 2062 AddToWorkList(SR, &C); 2063 else 2064 Postponed.push_back(SR); 2065 2066 return; 2067 } 2068 2069 if (isa<NonStaticGlobalSpaceRegion>(baseR)) { 2070 AddToWorkList(baseR, &C); 2071 return; 2072 } 2073 2074 // CXXThisRegion in the current or parent location context is live. 2075 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) { 2076 const StackArgumentsSpaceRegion *StackReg = 2077 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion()); 2078 const StackFrameContext *RegCtx = StackReg->getStackFrame(); 2079 if (CurrentLCtx && 2080 (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))) 2081 AddToWorkList(TR, &C); 2082 } 2083 } 2084 2085 void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR, 2086 const ClusterBindings &C) { 2087 // Mark the symbol for any SymbolicRegion with live bindings as live itself. 2088 // This means we should continue to track that symbol. 2089 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR)) 2090 SymReaper.markLive(SymR->getSymbol()); 2091 2092 for (ClusterBindings::iterator I = C.begin(), E = C.end(); I != E; ++I) 2093 VisitBinding(I.getData()); 2094 } 2095 2096 void removeDeadBindingsWorker::VisitBinding(SVal V) { 2097 // Is it a LazyCompoundVal? All referenced regions are live as well. 2098 if (Optional<nonloc::LazyCompoundVal> LCS = 2099 V.getAs<nonloc::LazyCompoundVal>()) { 2100 2101 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 2102 2103 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 2104 E = Vals.end(); 2105 I != E; ++I) 2106 VisitBinding(*I); 2107 2108 return; 2109 } 2110 2111 // If V is a region, then add it to the worklist. 2112 if (const MemRegion *R = V.getAsRegion()) { 2113 AddToWorkList(R); 2114 2115 // All regions captured by a block are also live. 2116 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) { 2117 BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(), 2118 E = BR->referenced_vars_end(); 2119 for ( ; I != E; ++I) 2120 AddToWorkList(I.getCapturedRegion()); 2121 } 2122 } 2123 2124 2125 // Update the set of live symbols. 2126 for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end(); 2127 SI!=SE; ++SI) 2128 SymReaper.markLive(*SI); 2129 } 2130 2131 bool removeDeadBindingsWorker::UpdatePostponed() { 2132 // See if any postponed SymbolicRegions are actually live now, after 2133 // having done a scan. 2134 bool changed = false; 2135 2136 for (SmallVectorImpl<const SymbolicRegion*>::iterator 2137 I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) { 2138 if (const SymbolicRegion *SR = *I) { 2139 if (SymReaper.isLive(SR->getSymbol())) { 2140 changed |= AddToWorkList(SR); 2141 *I = NULL; 2142 } 2143 } 2144 } 2145 2146 return changed; 2147 } 2148 2149 StoreRef RegionStoreManager::removeDeadBindings(Store store, 2150 const StackFrameContext *LCtx, 2151 SymbolReaper& SymReaper) { 2152 RegionBindingsRef B = getRegionBindings(store); 2153 removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx); 2154 W.GenerateClusters(); 2155 2156 // Enqueue the region roots onto the worklist. 2157 for (SymbolReaper::region_iterator I = SymReaper.region_begin(), 2158 E = SymReaper.region_end(); I != E; ++I) { 2159 W.AddToWorkList(*I); 2160 } 2161 2162 do W.RunWorkList(); while (W.UpdatePostponed()); 2163 2164 // We have now scanned the store, marking reachable regions and symbols 2165 // as live. We now remove all the regions that are dead from the store 2166 // as well as update DSymbols with the set symbols that are now dead. 2167 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 2168 const MemRegion *Base = I.getKey(); 2169 2170 // If the cluster has been visited, we know the region has been marked. 2171 if (W.isVisited(Base)) 2172 continue; 2173 2174 // Remove the dead entry. 2175 B = B.remove(Base); 2176 2177 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base)) 2178 SymReaper.maybeDead(SymR->getSymbol()); 2179 2180 // Mark all non-live symbols that this binding references as dead. 2181 const ClusterBindings &Cluster = I.getData(); 2182 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 2183 CI != CE; ++CI) { 2184 SVal X = CI.getData(); 2185 SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end(); 2186 for (; SI != SE; ++SI) 2187 SymReaper.maybeDead(*SI); 2188 } 2189 } 2190 2191 return StoreRef(B.asStore(), *this); 2192 } 2193 2194 //===----------------------------------------------------------------------===// 2195 // Utility methods. 2196 //===----------------------------------------------------------------------===// 2197 2198 void RegionStoreManager::print(Store store, raw_ostream &OS, 2199 const char* nl, const char *sep) { 2200 RegionBindingsRef B = getRegionBindings(store); 2201 OS << "Store (direct and default bindings), " 2202 << B.asStore() 2203 << " :" << nl; 2204 B.dump(OS, nl); 2205 } 2206