RegionStore.cpp revision b0abacf2f1f77214e4c77d6ec8a02b097bb98f7a
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 31using namespace clang; 32using namespace ento; 33using llvm::Optional; 34 35//===----------------------------------------------------------------------===// 36// Representation of binding keys. 37//===----------------------------------------------------------------------===// 38 39namespace { 40class BindingKey { 41public: 42 enum Kind { Default = 0x0, Direct = 0x1 }; 43private: 44 enum { Symbolic = 0x2 }; 45 46 llvm::PointerIntPair<const MemRegion *, 2> P; 47 uint64_t Data; 48 49 explicit BindingKey(const MemRegion *r, const MemRegion *Base, Kind k) 50 : P(r, k | Symbolic), Data(reinterpret_cast<uintptr_t>(Base)) { 51 assert(r && Base && "Must have known regions."); 52 assert(getConcreteOffsetRegion() == Base && "Failed to store base region"); 53 } 54 explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k) 55 : P(r, k), Data(offset) { 56 assert(r && "Must have known regions."); 57 assert(getOffset() == offset && "Failed to store offset"); 58 assert((r == r->getBaseRegion() || isa<ObjCIvarRegion>(r)) && "Not a base"); 59 } 60public: 61 62 bool isDirect() const { return P.getInt() & Direct; } 63 bool hasSymbolicOffset() const { return P.getInt() & Symbolic; } 64 65 const MemRegion *getRegion() const { return P.getPointer(); } 66 uint64_t getOffset() const { 67 assert(!hasSymbolicOffset()); 68 return Data; 69 } 70 71 const MemRegion *getConcreteOffsetRegion() const { 72 assert(hasSymbolicOffset()); 73 return reinterpret_cast<const MemRegion *>(static_cast<uintptr_t>(Data)); 74 } 75 76 const MemRegion *getBaseRegion() const { 77 if (hasSymbolicOffset()) 78 return getConcreteOffsetRegion()->getBaseRegion(); 79 return getRegion()->getBaseRegion(); 80 } 81 82 void Profile(llvm::FoldingSetNodeID& ID) const { 83 ID.AddPointer(P.getOpaqueValue()); 84 ID.AddInteger(Data); 85 } 86 87 static BindingKey Make(const MemRegion *R, Kind k); 88 89 bool operator<(const BindingKey &X) const { 90 if (P.getOpaqueValue() < X.P.getOpaqueValue()) 91 return true; 92 if (P.getOpaqueValue() > X.P.getOpaqueValue()) 93 return false; 94 return Data < X.Data; 95 } 96 97 bool operator==(const BindingKey &X) const { 98 return P.getOpaqueValue() == X.P.getOpaqueValue() && 99 Data == X.Data; 100 } 101 102 LLVM_ATTRIBUTE_USED void dump() const; 103}; 104} // end anonymous namespace 105 106BindingKey BindingKey::Make(const MemRegion *R, Kind k) { 107 const RegionOffset &RO = R->getAsOffset(); 108 if (RO.hasSymbolicOffset()) 109 return BindingKey(R, RO.getRegion(), k); 110 111 return BindingKey(RO.getRegion(), RO.getOffset(), k); 112} 113 114namespace llvm { 115 static inline 116 raw_ostream &operator<<(raw_ostream &os, BindingKey K) { 117 os << '(' << K.getRegion(); 118 if (!K.hasSymbolicOffset()) 119 os << ',' << K.getOffset(); 120 os << ',' << (K.isDirect() ? "direct" : "default") 121 << ')'; 122 return os; 123 } 124} // end llvm namespace 125 126void BindingKey::dump() const { 127 llvm::errs() << *this; 128} 129 130//===----------------------------------------------------------------------===// 131// Actual Store type. 132//===----------------------------------------------------------------------===// 133 134typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings; 135typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef; 136 137typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings> 138 RegionBindings; 139 140namespace { 141class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *, 142 ClusterBindings> { 143 ClusterBindings::Factory &CBFactory; 144public: 145 typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings> 146 ParentTy; 147 148 RegionBindingsRef(ClusterBindings::Factory &CBFactory, 149 const RegionBindings::TreeTy *T, 150 RegionBindings::TreeTy::Factory *F) 151 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F), 152 CBFactory(CBFactory) {} 153 154 RegionBindingsRef(const ParentTy &P, ClusterBindings::Factory &CBFactory) 155 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P), 156 CBFactory(CBFactory) {} 157 158 RegionBindingsRef add(key_type_ref K, data_type_ref D) const { 159 return RegionBindingsRef(static_cast<const ParentTy*>(this)->add(K, D), 160 CBFactory); 161 } 162 163 RegionBindingsRef remove(key_type_ref K) const { 164 return RegionBindingsRef(static_cast<const ParentTy*>(this)->remove(K), 165 CBFactory); 166 } 167 168 RegionBindingsRef addBinding(BindingKey K, SVal V) const; 169 170 RegionBindingsRef addBinding(const MemRegion *R, 171 BindingKey::Kind k, SVal V) const; 172 173 RegionBindingsRef &operator=(const RegionBindingsRef &X) { 174 *static_cast<ParentTy*>(this) = X; 175 return *this; 176 } 177 178 const SVal *lookup(BindingKey K) const; 179 const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const; 180 const ClusterBindings *lookup(const MemRegion *R) const { 181 return static_cast<const ParentTy*>(this)->lookup(R); 182 } 183 184 RegionBindingsRef removeBinding(BindingKey K); 185 186 RegionBindingsRef removeBinding(const MemRegion *R, 187 BindingKey::Kind k); 188 189 RegionBindingsRef removeBinding(const MemRegion *R) { 190 return removeBinding(R, BindingKey::Direct). 191 removeBinding(R, BindingKey::Default); 192 } 193 194 Optional<SVal> getDirectBinding(const MemRegion *R) const; 195 196 /// getDefaultBinding - Returns an SVal* representing an optional default 197 /// binding associated with a region and its subregions. 198 Optional<SVal> getDefaultBinding(const MemRegion *R) const; 199 200 /// Return the internal tree as a Store. 201 Store asStore() const { 202 return asImmutableMap().getRootWithoutRetain(); 203 } 204 205 void dump(llvm::raw_ostream &OS, const char *nl) const { 206 for (iterator I = begin(), E = end(); I != E; ++I) { 207 const ClusterBindings &Cluster = I.getData(); 208 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 209 CI != CE; ++CI) { 210 OS << ' ' << CI.getKey() << " : " << CI.getData() << nl; 211 } 212 OS << nl; 213 } 214 } 215 216 LLVM_ATTRIBUTE_USED void dump() const { 217 dump(llvm::errs(), "\n"); 218 } 219}; 220} // end anonymous namespace 221 222typedef const RegionBindingsRef& RegionBindingsConstRef; 223 224Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const { 225 if (const SVal *V = lookup(R, BindingKey::Direct)) 226 return *V; 227 return Optional<SVal>(); 228} 229 230Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const { 231 if (R->isBoundable()) 232 if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) 233 if (TR->getValueType()->isUnionType()) 234 return UnknownVal(); 235 if (const SVal *V = lookup(R, BindingKey::Default)) 236 return *V; 237 return Optional<SVal>(); 238} 239 240RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const { 241 const MemRegion *Base = K.getBaseRegion(); 242 243 const ClusterBindings *ExistingCluster = lookup(Base); 244 ClusterBindings Cluster = (ExistingCluster ? *ExistingCluster 245 : CBFactory.getEmptyMap()); 246 247 ClusterBindings NewCluster = CBFactory.add(Cluster, K, V); 248 return add(Base, NewCluster); 249} 250 251 252RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R, 253 BindingKey::Kind k, 254 SVal V) const { 255 return addBinding(BindingKey::Make(R, k), V); 256} 257 258const SVal *RegionBindingsRef::lookup(BindingKey K) const { 259 const ClusterBindings *Cluster = lookup(K.getBaseRegion()); 260 if (!Cluster) 261 return 0; 262 return Cluster->lookup(K); 263} 264 265const SVal *RegionBindingsRef::lookup(const MemRegion *R, 266 BindingKey::Kind k) const { 267 return lookup(BindingKey::Make(R, k)); 268} 269 270RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) { 271 const MemRegion *Base = K.getBaseRegion(); 272 const ClusterBindings *Cluster = lookup(Base); 273 if (!Cluster) 274 return *this; 275 276 ClusterBindings NewCluster = CBFactory.remove(*Cluster, K); 277 if (NewCluster.isEmpty()) 278 return remove(Base); 279 return add(Base, NewCluster); 280} 281 282RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R, 283 BindingKey::Kind k){ 284 return removeBinding(BindingKey::Make(R, k)); 285} 286 287//===----------------------------------------------------------------------===// 288// Fine-grained control of RegionStoreManager. 289//===----------------------------------------------------------------------===// 290 291namespace { 292struct minimal_features_tag {}; 293struct maximal_features_tag {}; 294 295class RegionStoreFeatures { 296 bool SupportsFields; 297public: 298 RegionStoreFeatures(minimal_features_tag) : 299 SupportsFields(false) {} 300 301 RegionStoreFeatures(maximal_features_tag) : 302 SupportsFields(true) {} 303 304 void enableFields(bool t) { SupportsFields = t; } 305 306 bool supportsFields() const { return SupportsFields; } 307}; 308} 309 310//===----------------------------------------------------------------------===// 311// Main RegionStore logic. 312//===----------------------------------------------------------------------===// 313 314namespace { 315 316class RegionStoreManager : public StoreManager { 317public: 318 const RegionStoreFeatures Features; 319 RegionBindings::Factory RBFactory; 320 mutable ClusterBindings::Factory CBFactory; 321 322 RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f) 323 : StoreManager(mgr), Features(f), 324 RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()) {} 325 326 327 /// setImplicitDefaultValue - Set the default binding for the provided 328 /// MemRegion to the value implicitly defined for compound literals when 329 /// the value is not specified. 330 RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B, 331 const MemRegion *R, QualType T); 332 333 /// ArrayToPointer - Emulates the "decay" of an array to a pointer 334 /// type. 'Array' represents the lvalue of the array being decayed 335 /// to a pointer, and the returned SVal represents the decayed 336 /// version of that lvalue (i.e., a pointer to the first element of 337 /// the array). This is called by ExprEngine when evaluating 338 /// casts from arrays to pointers. 339 SVal ArrayToPointer(Loc Array); 340 341 StoreRef getInitialStore(const LocationContext *InitLoc) { 342 return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this); 343 } 344 345 //===-------------------------------------------------------------------===// 346 // Binding values to regions. 347 //===-------------------------------------------------------------------===// 348 RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K, 349 const Expr *Ex, 350 unsigned Count, 351 const LocationContext *LCtx, 352 RegionBindingsRef B, 353 InvalidatedRegions *Invalidated); 354 355 StoreRef invalidateRegions(Store store, ArrayRef<const MemRegion *> Regions, 356 const Expr *E, unsigned Count, 357 const LocationContext *LCtx, 358 InvalidatedSymbols &IS, 359 const CallEvent *Call, 360 InvalidatedRegions *Invalidated); 361 362 bool scanReachableSymbols(Store S, const MemRegion *R, 363 ScanReachableSymbols &Callbacks); 364 365 RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B, 366 const SubRegion *R); 367 368public: // Part of public interface to class. 369 370 virtual StoreRef Bind(Store store, Loc LV, SVal V) { 371 return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this); 372 } 373 374 RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V); 375 376 // BindDefault is only used to initialize a region with a default value. 377 StoreRef BindDefault(Store store, const MemRegion *R, SVal V) { 378 RegionBindingsRef B = getRegionBindings(store); 379 assert(!B.lookup(R, BindingKey::Default)); 380 assert(!B.lookup(R, BindingKey::Direct)); 381 return StoreRef(B.addBinding(R, BindingKey::Default, V) 382 .asImmutableMap() 383 .getRootWithoutRetain(), *this); 384 } 385 386 /// \brief Create a new store that binds a value to a compound literal. 387 /// 388 /// \param ST The original store whose bindings are the basis for the new 389 /// store. 390 /// 391 /// \param CL The compound literal to bind (the binding key). 392 /// 393 /// \param LC The LocationContext for the binding. 394 /// 395 /// \param V The value to bind to the compound literal. 396 StoreRef bindCompoundLiteral(Store ST, 397 const CompoundLiteralExpr *CL, 398 const LocationContext *LC, SVal V); 399 400 /// BindStruct - Bind a compound value to a structure. 401 RegionBindingsRef bindStruct(RegionBindingsConstRef B, 402 const TypedValueRegion* R, SVal V); 403 404 /// BindVector - Bind a compound value to a vector. 405 RegionBindingsRef bindVector(RegionBindingsConstRef B, 406 const TypedValueRegion* R, SVal V); 407 408 RegionBindingsRef bindArray(RegionBindingsConstRef B, 409 const TypedValueRegion* R, 410 SVal V); 411 412 /// Clears out all bindings in the given region and assigns a new value 413 /// as a Default binding. 414 RegionBindingsRef bindAggregate(RegionBindingsConstRef B, 415 const TypedRegion *R, 416 SVal DefaultVal); 417 418 /// \brief Create a new store with the specified binding removed. 419 /// \param ST the original store, that is the basis for the new store. 420 /// \param L the location whose binding should be removed. 421 virtual StoreRef killBinding(Store ST, Loc L); 422 423 void incrementReferenceCount(Store store) { 424 getRegionBindings(store).manualRetain(); 425 } 426 427 /// If the StoreManager supports it, decrement the reference count of 428 /// the specified Store object. If the reference count hits 0, the memory 429 /// associated with the object is recycled. 430 void decrementReferenceCount(Store store) { 431 getRegionBindings(store).manualRelease(); 432 } 433 434 bool includedInBindings(Store store, const MemRegion *region) const; 435 436 /// \brief Return the value bound to specified location in a given state. 437 /// 438 /// The high level logic for this method is this: 439 /// getBinding (L) 440 /// if L has binding 441 /// return L's binding 442 /// else if L is in killset 443 /// return unknown 444 /// else 445 /// if L is on stack or heap 446 /// return undefined 447 /// else 448 /// return symbolic 449 virtual SVal getBinding(Store S, Loc L, QualType T) { 450 return getBinding(getRegionBindings(S), L, T); 451 } 452 453 SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType()); 454 455 SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R); 456 457 SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R); 458 459 SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R); 460 461 SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R); 462 463 SVal getBindingForLazySymbol(const TypedValueRegion *R); 464 465 SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 466 const TypedValueRegion *R, 467 QualType Ty, 468 const MemRegion *superR); 469 470 SVal getLazyBinding(const MemRegion *LazyBindingRegion, 471 RegionBindingsRef LazyBinding); 472 473 /// Get bindings for the values in a struct and return a CompoundVal, used 474 /// when doing struct copy: 475 /// struct s x, y; 476 /// x = y; 477 /// y's value is retrieved by this method. 478 SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion* R); 479 480 SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion* R); 481 482 /// Used to lazily generate derived symbols for bindings that are defined 483 /// implicitly by default bindings in a super region. 484 Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 485 const MemRegion *superR, 486 const TypedValueRegion *R, 487 QualType Ty); 488 489 /// Get the state and region whose binding this region R corresponds to. 490 std::pair<Store, const MemRegion*> 491 getLazyBinding(RegionBindingsConstRef B, const MemRegion *R, 492 const MemRegion *originalRegion, 493 bool includeSuffix = false); 494 495 //===------------------------------------------------------------------===// 496 // State pruning. 497 //===------------------------------------------------------------------===// 498 499 /// removeDeadBindings - Scans the RegionStore of 'state' for dead values. 500 /// It returns a new Store with these values removed. 501 StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, 502 SymbolReaper& SymReaper); 503 504 //===------------------------------------------------------------------===// 505 // Region "extents". 506 //===------------------------------------------------------------------===// 507 508 // FIXME: This method will soon be eliminated; see the note in Store.h. 509 DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state, 510 const MemRegion* R, QualType EleTy); 511 512 //===------------------------------------------------------------------===// 513 // Utility methods. 514 //===------------------------------------------------------------------===// 515 516 RegionBindingsRef getRegionBindings(Store store) const { 517 return RegionBindingsRef(CBFactory, 518 static_cast<const RegionBindings::TreeTy*>(store), 519 RBFactory.getTreeFactory()); 520 } 521 522 void print(Store store, raw_ostream &Out, const char* nl, 523 const char *sep); 524 525 void iterBindings(Store store, BindingsHandler& f) { 526 RegionBindingsRef B = getRegionBindings(store); 527 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 528 const ClusterBindings &Cluster = I.getData(); 529 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 530 CI != CE; ++CI) { 531 const BindingKey &K = CI.getKey(); 532 if (!K.isDirect()) 533 continue; 534 if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) { 535 // FIXME: Possibly incorporate the offset? 536 if (!f.HandleBinding(*this, store, R, CI.getData())) 537 return; 538 } 539 } 540 } 541 } 542}; 543 544} // end anonymous namespace 545 546//===----------------------------------------------------------------------===// 547// RegionStore creation. 548//===----------------------------------------------------------------------===// 549 550StoreManager *ento::CreateRegionStoreManager(ProgramStateManager& StMgr) { 551 RegionStoreFeatures F = maximal_features_tag(); 552 return new RegionStoreManager(StMgr, F); 553} 554 555StoreManager * 556ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) { 557 RegionStoreFeatures F = minimal_features_tag(); 558 F.enableFields(true); 559 return new RegionStoreManager(StMgr, F); 560} 561 562 563//===----------------------------------------------------------------------===// 564// Region Cluster analysis. 565//===----------------------------------------------------------------------===// 566 567namespace { 568template <typename DERIVED> 569class ClusterAnalysis { 570protected: 571 typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap; 572 typedef SmallVector<const MemRegion *, 10> WorkList; 573 574 llvm::SmallPtrSet<const ClusterBindings *, 16> Visited; 575 576 WorkList WL; 577 578 RegionStoreManager &RM; 579 ASTContext &Ctx; 580 SValBuilder &svalBuilder; 581 582 RegionBindingsRef B; 583 584 const bool includeGlobals; 585 586 const ClusterBindings *getCluster(const MemRegion *R) { 587 return B.lookup(R); 588 } 589 590public: 591 ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr, 592 RegionBindingsRef b, const bool includeGlobals) 593 : RM(rm), Ctx(StateMgr.getContext()), 594 svalBuilder(StateMgr.getSValBuilder()), 595 B(b), includeGlobals(includeGlobals) {} 596 597 RegionBindingsRef getRegionBindings() const { return B; } 598 599 bool isVisited(const MemRegion *R) { 600 return Visited.count(getCluster(R)); 601 } 602 603 void GenerateClusters() { 604 // Scan the entire set of bindings and record the region clusters. 605 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); 606 RI != RE; ++RI){ 607 const MemRegion *Base = RI.getKey(); 608 609 const ClusterBindings &Cluster = RI.getData(); 610 assert(!Cluster.isEmpty() && "Empty clusters should be removed"); 611 static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster); 612 613 if (includeGlobals) 614 if (isa<NonStaticGlobalSpaceRegion>(Base->getMemorySpace())) 615 AddToWorkList(Base, &Cluster); 616 } 617 } 618 619 bool AddToWorkList(const MemRegion *R, const ClusterBindings *C) { 620 if (C && !Visited.insert(C)) 621 return false; 622 WL.push_back(R); 623 return true; 624 } 625 626 bool AddToWorkList(const MemRegion *R) { 627 const MemRegion *baseR = R->getBaseRegion(); 628 return AddToWorkList(baseR, getCluster(baseR)); 629 } 630 631 void RunWorkList() { 632 while (!WL.empty()) { 633 const MemRegion *baseR = WL.pop_back_val(); 634 635 // First visit the cluster. 636 if (const ClusterBindings *Cluster = getCluster(baseR)) 637 static_cast<DERIVED*>(this)->VisitCluster(baseR, *Cluster); 638 639 // Next, visit the base region. 640 static_cast<DERIVED*>(this)->VisitBaseRegion(baseR); 641 } 642 } 643 644public: 645 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {} 646 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C) {} 647 void VisitBaseRegion(const MemRegion *baseR) {} 648}; 649} 650 651//===----------------------------------------------------------------------===// 652// Binding invalidation. 653//===----------------------------------------------------------------------===// 654 655bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R, 656 ScanReachableSymbols &Callbacks) { 657 assert(R == R->getBaseRegion() && "Should only be called for base regions"); 658 RegionBindingsRef B = getRegionBindings(S); 659 const ClusterBindings *Cluster = B.lookup(R); 660 661 if (!Cluster) 662 return true; 663 664 for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end(); 665 RI != RE; ++RI) { 666 if (!Callbacks.scan(RI.getData())) 667 return false; 668 } 669 670 return true; 671} 672 673static inline bool isUnionField(const FieldRegion *FR) { 674 return FR->getDecl()->getParent()->isUnion(); 675} 676 677typedef SmallVector<const FieldDecl *, 8> FieldVector; 678 679void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) { 680 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 681 682 const MemRegion *Base = K.getConcreteOffsetRegion(); 683 const MemRegion *R = K.getRegion(); 684 685 while (R != Base) { 686 if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) 687 if (!isUnionField(FR)) 688 Fields.push_back(FR->getDecl()); 689 690 R = cast<SubRegion>(R)->getSuperRegion(); 691 } 692} 693 694static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) { 695 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 696 697 if (Fields.empty()) 698 return true; 699 700 FieldVector FieldsInBindingKey; 701 getSymbolicOffsetFields(K, FieldsInBindingKey); 702 703 ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size(); 704 if (Delta >= 0) 705 return std::equal(FieldsInBindingKey.begin() + Delta, 706 FieldsInBindingKey.end(), 707 Fields.begin()); 708 else 709 return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(), 710 Fields.begin() - Delta); 711} 712 713RegionBindingsRef 714RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B, 715 const SubRegion *R) { 716 BindingKey SRKey = BindingKey::Make(R, BindingKey::Default); 717 const MemRegion *ClusterHead = SRKey.getBaseRegion(); 718 if (R == ClusterHead) { 719 // We can remove an entire cluster's bindings all in one go. 720 return B.remove(R); 721 } 722 723 FieldVector FieldsInSymbolicSubregions; 724 bool HasSymbolicOffset = SRKey.hasSymbolicOffset(); 725 if (HasSymbolicOffset) { 726 getSymbolicOffsetFields(SRKey, FieldsInSymbolicSubregions); 727 R = cast<SubRegion>(SRKey.getConcreteOffsetRegion()); 728 SRKey = BindingKey::Make(R, BindingKey::Default); 729 } 730 731 // This assumes the region being invalidated is char-aligned. This isn't 732 // true for bitfields, but since bitfields have no subregions they shouldn't 733 // be using this function anyway. 734 uint64_t Length = UINT64_MAX; 735 736 SVal Extent = R->getExtent(svalBuilder); 737 if (nonloc::ConcreteInt *ExtentCI = dyn_cast<nonloc::ConcreteInt>(&Extent)) { 738 const llvm::APSInt &ExtentInt = ExtentCI->getValue(); 739 assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned()); 740 // Extents are in bytes but region offsets are in bits. Be careful! 741 Length = ExtentInt.getLimitedValue() * Ctx.getCharWidth(); 742 } 743 744 const ClusterBindings *Cluster = B.lookup(ClusterHead); 745 if (!Cluster) 746 return B; 747 748 ClusterBindingsRef Result(*Cluster, CBFactory); 749 750 // It is safe to iterate over the bindings as they are being changed 751 // because they are in an ImmutableMap. 752 for (ClusterBindings::iterator I = Cluster->begin(), E = Cluster->end(); 753 I != E; ++I) { 754 BindingKey NextKey = I.getKey(); 755 if (NextKey.getRegion() == SRKey.getRegion()) { 756 // FIXME: This doesn't catch the case where we're really invalidating a 757 // region with a symbolic offset. Example: 758 // R: points[i].y 759 // Next: points[0].x 760 761 if (NextKey.getOffset() > SRKey.getOffset() && 762 NextKey.getOffset() - SRKey.getOffset() < Length) { 763 // Case 1: The next binding is inside the region we're invalidating. 764 // Remove it. 765 Result = Result.remove(NextKey); 766 767 } else if (NextKey.getOffset() == SRKey.getOffset()) { 768 // Case 2: The next binding is at the same offset as the region we're 769 // invalidating. In this case, we need to leave default bindings alone, 770 // since they may be providing a default value for a regions beyond what 771 // we're invalidating. 772 // FIXME: This is probably incorrect; consider invalidating an outer 773 // struct whose first field is bound to a LazyCompoundVal. 774 if (NextKey.isDirect()) 775 Result = Result.remove(NextKey); 776 } 777 778 } else if (NextKey.hasSymbolicOffset()) { 779 const MemRegion *Base = NextKey.getConcreteOffsetRegion(); 780 if (R->isSubRegionOf(Base)) { 781 // Case 3: The next key is symbolic and we just changed something within 782 // its concrete region. We don't know if the binding is still valid, so 783 // we'll be conservative and remove it. 784 if (NextKey.isDirect()) 785 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 786 Result = Result.remove(NextKey); 787 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) { 788 // Case 4: The next key is symbolic, but we changed a known 789 // super-region. In this case the binding is certainly no longer valid. 790 if (R == Base || BaseSR->isSubRegionOf(R)) 791 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 792 Result = Result.remove(NextKey); 793 } 794 } 795 } 796 797 // If we're invalidating a region with a symbolic offset, we need to make sure 798 // we don't treat the base region as uninitialized anymore. 799 // FIXME: This isn't very precise; see the example in the loop. 800 if (HasSymbolicOffset) 801 Result = Result.add(SRKey, UnknownVal()); 802 803 if (Result.isEmpty()) 804 return B.remove(ClusterHead); 805 return B.add(ClusterHead, Result.asImmutableMap()); 806} 807 808namespace { 809class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker> 810{ 811 const Expr *Ex; 812 unsigned Count; 813 const LocationContext *LCtx; 814 StoreManager::InvalidatedSymbols &IS; 815 StoreManager::InvalidatedRegions *Regions; 816public: 817 invalidateRegionsWorker(RegionStoreManager &rm, 818 ProgramStateManager &stateMgr, 819 RegionBindingsRef b, 820 const Expr *ex, unsigned count, 821 const LocationContext *lctx, 822 StoreManager::InvalidatedSymbols &is, 823 StoreManager::InvalidatedRegions *r, 824 bool includeGlobals) 825 : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, includeGlobals), 826 Ex(ex), Count(count), LCtx(lctx), IS(is), Regions(r) {} 827 828 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C); 829 void VisitBaseRegion(const MemRegion *baseR); 830 831private: 832 void VisitBinding(SVal V); 833}; 834} 835 836void invalidateRegionsWorker::VisitBinding(SVal V) { 837 // A symbol? Mark it touched by the invalidation. 838 if (SymbolRef Sym = V.getAsSymbol()) 839 IS.insert(Sym); 840 841 if (const MemRegion *R = V.getAsRegion()) { 842 AddToWorkList(R); 843 return; 844 } 845 846 // Is it a LazyCompoundVal? All references get invalidated as well. 847 if (const nonloc::LazyCompoundVal *LCS = 848 dyn_cast<nonloc::LazyCompoundVal>(&V)) { 849 850 const MemRegion *LazyR = LCS->getRegion(); 851 RegionBindingsRef B = RM.getRegionBindings(LCS->getStore()); 852 853 // FIXME: This should not have to walk all bindings in the old store. 854 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){ 855 const ClusterBindings &Cluster = RI.getData(); 856 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 857 CI != CE; ++CI) { 858 BindingKey K = CI.getKey(); 859 if (const SubRegion *BaseR = dyn_cast<SubRegion>(K.getRegion())) { 860 if (BaseR == LazyR) 861 VisitBinding(CI.getData()); 862 else if (K.hasSymbolicOffset() && BaseR->isSubRegionOf(LazyR)) 863 VisitBinding(CI.getData()); 864 } 865 } 866 } 867 868 return; 869 } 870} 871 872void invalidateRegionsWorker::VisitCluster(const MemRegion *BaseR, 873 const ClusterBindings &C) { 874 for (ClusterBindings::iterator I = C.begin(), E = C.end(); I != E; ++I) 875 VisitBinding(I.getData()); 876 877 B = B.remove(BaseR); 878} 879 880void invalidateRegionsWorker::VisitBaseRegion(const MemRegion *baseR) { 881 // Symbolic region? Mark that symbol touched by the invalidation. 882 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) 883 IS.insert(SR->getSymbol()); 884 885 // BlockDataRegion? If so, invalidate captured variables that are passed 886 // by reference. 887 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) { 888 for (BlockDataRegion::referenced_vars_iterator 889 BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ; 890 BI != BE; ++BI) { 891 const VarRegion *VR = BI.getCapturedRegion(); 892 const VarDecl *VD = VR->getDecl(); 893 if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage()) { 894 AddToWorkList(VR); 895 } 896 else if (Loc::isLocType(VR->getValueType())) { 897 // Map the current bindings to a Store to retrieve the value 898 // of the binding. If that binding itself is a region, we should 899 // invalidate that region. This is because a block may capture 900 // a pointer value, but the thing pointed by that pointer may 901 // get invalidated. 902 SVal V = RM.getBinding(B, loc::MemRegionVal(VR)); 903 if (const Loc *L = dyn_cast<Loc>(&V)) { 904 if (const MemRegion *LR = L->getAsRegion()) 905 AddToWorkList(LR); 906 } 907 } 908 } 909 return; 910 } 911 912 // Otherwise, we have a normal data region. Record that we touched the region. 913 if (Regions) 914 Regions->push_back(baseR); 915 916 if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) { 917 // Invalidate the region by setting its default value to 918 // conjured symbol. The type of the symbol is irrelavant. 919 DefinedOrUnknownSVal V = 920 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count); 921 B = B.addBinding(baseR, BindingKey::Default, V); 922 return; 923 } 924 925 if (!baseR->isBoundable()) 926 return; 927 928 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR); 929 QualType T = TR->getValueType(); 930 931 // Invalidate the binding. 932 if (T->isStructureOrClassType()) { 933 // Invalidate the region by setting its default value to 934 // conjured symbol. The type of the symbol is irrelavant. 935 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 936 Ctx.IntTy, Count); 937 B = B.addBinding(baseR, BindingKey::Default, V); 938 return; 939 } 940 941 if (const ArrayType *AT = Ctx.getAsArrayType(T)) { 942 // Set the default value of the array to conjured symbol. 943 DefinedOrUnknownSVal V = 944 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 945 AT->getElementType(), Count); 946 B = B.addBinding(baseR, BindingKey::Default, V); 947 return; 948 } 949 950 if (includeGlobals && 951 isa<NonStaticGlobalSpaceRegion>(baseR->getMemorySpace())) { 952 // If the region is a global and we are invalidating all globals, 953 // just erase the entry. This causes all globals to be lazily 954 // symbolicated from the same base symbol. 955 B = B.removeBinding(baseR); 956 return; 957 } 958 959 960 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 961 T,Count); 962 assert(SymbolManager::canSymbolicate(T) || V.isUnknown()); 963 B = B.addBinding(baseR, BindingKey::Direct, V); 964} 965 966RegionBindingsRef 967RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K, 968 const Expr *Ex, 969 unsigned Count, 970 const LocationContext *LCtx, 971 RegionBindingsRef B, 972 InvalidatedRegions *Invalidated) { 973 // Bind the globals memory space to a new symbol that we will use to derive 974 // the bindings for all globals. 975 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K); 976 SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx, 977 /* type does not matter */ Ctx.IntTy, 978 Count); 979 980 B = B.removeBinding(GS) 981 .addBinding(BindingKey::Make(GS, BindingKey::Default), V); 982 983 // Even if there are no bindings in the global scope, we still need to 984 // record that we touched it. 985 if (Invalidated) 986 Invalidated->push_back(GS); 987 988 return B; 989} 990 991StoreRef 992RegionStoreManager::invalidateRegions(Store store, 993 ArrayRef<const MemRegion *> Regions, 994 const Expr *Ex, unsigned Count, 995 const LocationContext *LCtx, 996 InvalidatedSymbols &IS, 997 const CallEvent *Call, 998 InvalidatedRegions *Invalidated) { 999 invalidateRegionsWorker W(*this, StateMgr, 1000 RegionStoreManager::getRegionBindings(store), 1001 Ex, Count, LCtx, IS, Invalidated, false); 1002 1003 // Scan the bindings and generate the clusters. 1004 W.GenerateClusters(); 1005 1006 // Add the regions to the worklist. 1007 for (ArrayRef<const MemRegion *>::iterator 1008 I = Regions.begin(), E = Regions.end(); I != E; ++I) 1009 W.AddToWorkList(*I); 1010 1011 W.RunWorkList(); 1012 1013 // Return the new bindings. 1014 RegionBindingsRef B = W.getRegionBindings(); 1015 1016 // For all globals which are not static nor immutable: determine which global 1017 // regions should be invalidated and invalidate them. 1018 // TODO: This could possibly be more precise with modules. 1019 // 1020 // System calls invalidate only system globals. 1021 if (Call && Call->isInSystemHeader()) { 1022 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1023 Ex, Count, LCtx, B, Invalidated); 1024 // Internal calls might invalidate both system and internal globals. 1025 } else { 1026 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1027 Ex, Count, LCtx, B, Invalidated); 1028 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind, 1029 Ex, Count, LCtx, B, Invalidated); 1030 } 1031 1032 return StoreRef(B.asStore(), *this); 1033} 1034 1035//===----------------------------------------------------------------------===// 1036// Extents for regions. 1037//===----------------------------------------------------------------------===// 1038 1039DefinedOrUnknownSVal 1040RegionStoreManager::getSizeInElements(ProgramStateRef state, 1041 const MemRegion *R, 1042 QualType EleTy) { 1043 SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder); 1044 const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size); 1045 if (!SizeInt) 1046 return UnknownVal(); 1047 1048 CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue()); 1049 1050 if (Ctx.getAsVariableArrayType(EleTy)) { 1051 // FIXME: We need to track extra state to properly record the size 1052 // of VLAs. Returning UnknownVal here, however, is a stop-gap so that 1053 // we don't have a divide-by-zero below. 1054 return UnknownVal(); 1055 } 1056 1057 CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy); 1058 1059 // If a variable is reinterpreted as a type that doesn't fit into a larger 1060 // type evenly, round it down. 1061 // This is a signed value, since it's used in arithmetic with signed indices. 1062 return svalBuilder.makeIntVal(RegionSize / EleSize, false); 1063} 1064 1065//===----------------------------------------------------------------------===// 1066// Location and region casting. 1067//===----------------------------------------------------------------------===// 1068 1069/// ArrayToPointer - Emulates the "decay" of an array to a pointer 1070/// type. 'Array' represents the lvalue of the array being decayed 1071/// to a pointer, and the returned SVal represents the decayed 1072/// version of that lvalue (i.e., a pointer to the first element of 1073/// the array). This is called by ExprEngine when evaluating casts 1074/// from arrays to pointers. 1075SVal RegionStoreManager::ArrayToPointer(Loc Array) { 1076 if (!isa<loc::MemRegionVal>(Array)) 1077 return UnknownVal(); 1078 1079 const MemRegion* R = cast<loc::MemRegionVal>(&Array)->getRegion(); 1080 const TypedValueRegion* ArrayR = dyn_cast<TypedValueRegion>(R); 1081 1082 if (!ArrayR) 1083 return UnknownVal(); 1084 1085 // Strip off typedefs from the ArrayRegion's ValueType. 1086 QualType T = ArrayR->getValueType().getDesugaredType(Ctx); 1087 const ArrayType *AT = cast<ArrayType>(T); 1088 T = AT->getElementType(); 1089 1090 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex(); 1091 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, ArrayR, Ctx)); 1092} 1093 1094//===----------------------------------------------------------------------===// 1095// Loading values from regions. 1096//===----------------------------------------------------------------------===// 1097 1098SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) { 1099 assert(!isa<UnknownVal>(L) && "location unknown"); 1100 assert(!isa<UndefinedVal>(L) && "location undefined"); 1101 1102 // For access to concrete addresses, return UnknownVal. Checks 1103 // for null dereferences (and similar errors) are done by checkers, not 1104 // the Store. 1105 // FIXME: We can consider lazily symbolicating such memory, but we really 1106 // should defer this when we can reason easily about symbolicating arrays 1107 // of bytes. 1108 if (isa<loc::ConcreteInt>(L)) { 1109 return UnknownVal(); 1110 } 1111 if (!isa<loc::MemRegionVal>(L)) { 1112 return UnknownVal(); 1113 } 1114 1115 const MemRegion *MR = cast<loc::MemRegionVal>(L).getRegion(); 1116 1117 if (isa<AllocaRegion>(MR) || 1118 isa<SymbolicRegion>(MR) || 1119 isa<CodeTextRegion>(MR)) { 1120 if (T.isNull()) { 1121 if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR)) 1122 T = TR->getLocationType(); 1123 else { 1124 const SymbolicRegion *SR = cast<SymbolicRegion>(MR); 1125 T = SR->getSymbol()->getType(); 1126 } 1127 } 1128 MR = GetElementZeroRegion(MR, T); 1129 } 1130 1131 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument 1132 // instead of 'Loc', and have the other Loc cases handled at a higher level. 1133 const TypedValueRegion *R = cast<TypedValueRegion>(MR); 1134 QualType RTy = R->getValueType(); 1135 1136 // FIXME: We should eventually handle funny addressing. e.g.: 1137 // 1138 // int x = ...; 1139 // int *p = &x; 1140 // char *q = (char*) p; 1141 // char c = *q; // returns the first byte of 'x'. 1142 // 1143 // Such funny addressing will occur due to layering of regions. 1144 if (RTy->isStructureOrClassType()) 1145 return getBindingForStruct(B, R); 1146 1147 // FIXME: Handle unions. 1148 if (RTy->isUnionType()) 1149 return UnknownVal(); 1150 1151 if (RTy->isArrayType()) { 1152 if (RTy->isConstantArrayType()) 1153 return getBindingForArray(B, R); 1154 else 1155 return UnknownVal(); 1156 } 1157 1158 // FIXME: handle Vector types. 1159 if (RTy->isVectorType()) 1160 return UnknownVal(); 1161 1162 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R)) 1163 return CastRetrievedVal(getBindingForField(B, FR), FR, T, false); 1164 1165 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) { 1166 // FIXME: Here we actually perform an implicit conversion from the loaded 1167 // value to the element type. Eventually we want to compose these values 1168 // more intelligently. For example, an 'element' can encompass multiple 1169 // bound regions (e.g., several bound bytes), or could be a subset of 1170 // a larger value. 1171 return CastRetrievedVal(getBindingForElement(B, ER), ER, T, false); 1172 } 1173 1174 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) { 1175 // FIXME: Here we actually perform an implicit conversion from the loaded 1176 // value to the ivar type. What we should model is stores to ivars 1177 // that blow past the extent of the ivar. If the address of the ivar is 1178 // reinterpretted, it is possible we stored a different value that could 1179 // fit within the ivar. Either we need to cast these when storing them 1180 // or reinterpret them lazily (as we do here). 1181 return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T, false); 1182 } 1183 1184 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { 1185 // FIXME: Here we actually perform an implicit conversion from the loaded 1186 // value to the variable type. What we should model is stores to variables 1187 // that blow past the extent of the variable. If the address of the 1188 // variable is reinterpretted, it is possible we stored a different value 1189 // that could fit within the variable. Either we need to cast these when 1190 // storing them or reinterpret them lazily (as we do here). 1191 return CastRetrievedVal(getBindingForVar(B, VR), VR, T, false); 1192 } 1193 1194 const SVal *V = B.lookup(R, BindingKey::Direct); 1195 1196 // Check if the region has a binding. 1197 if (V) 1198 return *V; 1199 1200 // The location does not have a bound value. This means that it has 1201 // the value it had upon its creation and/or entry to the analyzed 1202 // function/method. These are either symbolic values or 'undefined'. 1203 if (R->hasStackNonParametersStorage()) { 1204 // All stack variables are considered to have undefined values 1205 // upon creation. All heap allocated blocks are considered to 1206 // have undefined values as well unless they are explicitly bound 1207 // to specific values. 1208 return UndefinedVal(); 1209 } 1210 1211 // All other values are symbolic. 1212 return svalBuilder.getRegionValueSymbolVal(R); 1213} 1214 1215std::pair<Store, const MemRegion *> 1216RegionStoreManager::getLazyBinding(RegionBindingsConstRef B, 1217 const MemRegion *R, 1218 const MemRegion *originalRegion, 1219 bool includeSuffix) { 1220 1221 if (originalRegion != R) { 1222 if (Optional<SVal> OV = B.getDefaultBinding(R)) { 1223 if (const nonloc::LazyCompoundVal *V = 1224 dyn_cast<nonloc::LazyCompoundVal>(OV.getPointer())) 1225 return std::make_pair(V->getStore(), V->getRegion()); 1226 } 1227 } 1228 1229 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 1230 const std::pair<Store, const MemRegion *> &X = 1231 getLazyBinding(B, ER->getSuperRegion(), originalRegion); 1232 1233 if (X.second) 1234 return std::make_pair(X.first, 1235 MRMgr.getElementRegionWithSuper(ER, X.second)); 1236 } 1237 else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) { 1238 const std::pair<Store, const MemRegion *> &X = 1239 getLazyBinding(B, FR->getSuperRegion(), originalRegion); 1240 1241 if (X.second) { 1242 if (includeSuffix) 1243 return std::make_pair(X.first, 1244 MRMgr.getFieldRegionWithSuper(FR, X.second)); 1245 return X; 1246 } 1247 1248 } 1249 // C++ base object region is another kind of region that we should blast 1250 // through to look for lazy compound value. It is like a field region. 1251 else if (const CXXBaseObjectRegion *baseReg = 1252 dyn_cast<CXXBaseObjectRegion>(R)) { 1253 const std::pair<Store, const MemRegion *> &X = 1254 getLazyBinding(B, baseReg->getSuperRegion(), originalRegion); 1255 1256 if (X.second) { 1257 if (includeSuffix) 1258 return std::make_pair(X.first, 1259 MRMgr.getCXXBaseObjectRegionWithSuper(baseReg, 1260 X.second)); 1261 return X; 1262 } 1263 } 1264 1265 // The NULL MemRegion indicates an non-existent lazy binding. A NULL Store is 1266 // possible for a valid lazy binding. 1267 return std::make_pair((Store) 0, (const MemRegion *) 0); 1268} 1269 1270SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B, 1271 const ElementRegion* R) { 1272 // We do not currently model bindings of the CompoundLiteralregion. 1273 if (isa<CompoundLiteralRegion>(R->getBaseRegion())) 1274 return UnknownVal(); 1275 1276 // Check if the region has a binding. 1277 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1278 return *V; 1279 1280 const MemRegion* superR = R->getSuperRegion(); 1281 1282 // Check if the region is an element region of a string literal. 1283 if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) { 1284 // FIXME: Handle loads from strings where the literal is treated as 1285 // an integer, e.g., *((unsigned int*)"hello") 1286 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType(); 1287 if (T != Ctx.getCanonicalType(R->getElementType())) 1288 return UnknownVal(); 1289 1290 const StringLiteral *Str = StrR->getStringLiteral(); 1291 SVal Idx = R->getIndex(); 1292 if (nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(&Idx)) { 1293 int64_t i = CI->getValue().getSExtValue(); 1294 // Abort on string underrun. This can be possible by arbitrary 1295 // clients of getBindingForElement(). 1296 if (i < 0) 1297 return UndefinedVal(); 1298 int64_t length = Str->getLength(); 1299 // Technically, only i == length is guaranteed to be null. 1300 // However, such overflows should be caught before reaching this point; 1301 // the only time such an access would be made is if a string literal was 1302 // used to initialize a larger array. 1303 char c = (i >= length) ? '\0' : Str->getCodeUnit(i); 1304 return svalBuilder.makeIntVal(c, T); 1305 } 1306 } 1307 1308 // Check for loads from a code text region. For such loads, just give up. 1309 if (isa<CodeTextRegion>(superR)) 1310 return UnknownVal(); 1311 1312 // Handle the case where we are indexing into a larger scalar object. 1313 // For example, this handles: 1314 // int x = ... 1315 // char *y = &x; 1316 // return *y; 1317 // FIXME: This is a hack, and doesn't do anything really intelligent yet. 1318 const RegionRawOffset &O = R->getAsArrayOffset(); 1319 1320 // If we cannot reason about the offset, return an unknown value. 1321 if (!O.getRegion()) 1322 return UnknownVal(); 1323 1324 if (const TypedValueRegion *baseR = 1325 dyn_cast_or_null<TypedValueRegion>(O.getRegion())) { 1326 QualType baseT = baseR->getValueType(); 1327 if (baseT->isScalarType()) { 1328 QualType elemT = R->getElementType(); 1329 if (elemT->isScalarType()) { 1330 if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) { 1331 if (const Optional<SVal> &V = B.getDirectBinding(superR)) { 1332 if (SymbolRef parentSym = V->getAsSymbol()) 1333 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1334 1335 if (V->isUnknownOrUndef()) 1336 return *V; 1337 // Other cases: give up. We are indexing into a larger object 1338 // that has some value, but we don't know how to handle that yet. 1339 return UnknownVal(); 1340 } 1341 } 1342 } 1343 } 1344 } 1345 return getBindingForFieldOrElementCommon(B, R, R->getElementType(), 1346 superR); 1347} 1348 1349SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B, 1350 const FieldRegion* R) { 1351 1352 // Check if the region has a binding. 1353 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1354 return *V; 1355 1356 QualType Ty = R->getValueType(); 1357 return getBindingForFieldOrElementCommon(B, R, Ty, R->getSuperRegion()); 1358} 1359 1360Optional<SVal> 1361RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 1362 const MemRegion *superR, 1363 const TypedValueRegion *R, 1364 QualType Ty) { 1365 1366 if (const Optional<SVal> &D = B.getDefaultBinding(superR)) { 1367 const SVal &val = D.getValue(); 1368 if (SymbolRef parentSym = val.getAsSymbol()) 1369 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1370 1371 if (val.isZeroConstant()) 1372 return svalBuilder.makeZeroVal(Ty); 1373 1374 if (val.isUnknownOrUndef()) 1375 return val; 1376 1377 // Lazy bindings are handled later. 1378 if (isa<nonloc::LazyCompoundVal>(val)) 1379 return Optional<SVal>(); 1380 1381 llvm_unreachable("Unknown default value"); 1382 } 1383 1384 return Optional<SVal>(); 1385} 1386 1387SVal RegionStoreManager::getLazyBinding(const MemRegion *LazyBindingRegion, 1388 RegionBindingsRef LazyBinding) { 1389 if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion)) 1390 return getBindingForElement(LazyBinding, ER); 1391 return getBindingForField(LazyBinding, cast<FieldRegion>(LazyBindingRegion)); 1392} 1393 1394SVal 1395RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 1396 const TypedValueRegion *R, 1397 QualType Ty, 1398 const MemRegion *superR) { 1399 1400 // At this point we have already checked in either getBindingForElement or 1401 // getBindingForField if 'R' has a direct binding. 1402 1403 // Lazy binding? 1404 Store lazyBindingStore = NULL; 1405 const MemRegion *lazyBindingRegion = NULL; 1406 llvm::tie(lazyBindingStore, lazyBindingRegion) = getLazyBinding(B, R, R, 1407 true); 1408 if (lazyBindingRegion) 1409 return getLazyBinding(lazyBindingRegion, 1410 getRegionBindings(lazyBindingStore)); 1411 1412 // Record whether or not we see a symbolic index. That can completely 1413 // be out of scope of our lookup. 1414 bool hasSymbolicIndex = false; 1415 1416 while (superR) { 1417 if (const Optional<SVal> &D = 1418 getBindingForDerivedDefaultValue(B, superR, R, Ty)) 1419 return *D; 1420 1421 if (const ElementRegion *ER = dyn_cast<ElementRegion>(superR)) { 1422 NonLoc index = ER->getIndex(); 1423 if (!index.isConstant()) 1424 hasSymbolicIndex = true; 1425 } 1426 1427 // If our super region is a field or element itself, walk up the region 1428 // hierarchy to see if there is a default value installed in an ancestor. 1429 if (const SubRegion *SR = dyn_cast<SubRegion>(superR)) { 1430 superR = SR->getSuperRegion(); 1431 continue; 1432 } 1433 break; 1434 } 1435 1436 if (R->hasStackNonParametersStorage()) { 1437 if (isa<ElementRegion>(R)) { 1438 // Currently we don't reason specially about Clang-style vectors. Check 1439 // if superR is a vector and if so return Unknown. 1440 if (const TypedValueRegion *typedSuperR = 1441 dyn_cast<TypedValueRegion>(superR)) { 1442 if (typedSuperR->getValueType()->isVectorType()) 1443 return UnknownVal(); 1444 } 1445 } 1446 1447 // FIXME: We also need to take ElementRegions with symbolic indexes into 1448 // account. This case handles both directly accessing an ElementRegion 1449 // with a symbolic offset, but also fields within an element with 1450 // a symbolic offset. 1451 if (hasSymbolicIndex) 1452 return UnknownVal(); 1453 1454 return UndefinedVal(); 1455 } 1456 1457 // All other values are symbolic. 1458 return svalBuilder.getRegionValueSymbolVal(R); 1459} 1460 1461SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B, 1462 const ObjCIvarRegion* R) { 1463 // Check if the region has a binding. 1464 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1465 return *V; 1466 1467 const MemRegion *superR = R->getSuperRegion(); 1468 1469 // Check if the super region has a default binding. 1470 if (const Optional<SVal> &V = B.getDefaultBinding(superR)) { 1471 if (SymbolRef parentSym = V->getAsSymbol()) 1472 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1473 1474 // Other cases: give up. 1475 return UnknownVal(); 1476 } 1477 1478 return getBindingForLazySymbol(R); 1479} 1480 1481SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B, 1482 const VarRegion *R) { 1483 1484 // Check if the region has a binding. 1485 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1486 return *V; 1487 1488 // Lazily derive a value for the VarRegion. 1489 const VarDecl *VD = R->getDecl(); 1490 QualType T = VD->getType(); 1491 const MemSpaceRegion *MS = R->getMemorySpace(); 1492 1493 if (isa<UnknownSpaceRegion>(MS) || 1494 isa<StackArgumentsSpaceRegion>(MS)) 1495 return svalBuilder.getRegionValueSymbolVal(R); 1496 1497 if (isa<GlobalsSpaceRegion>(MS)) { 1498 if (isa<NonStaticGlobalSpaceRegion>(MS)) { 1499 // Is 'VD' declared constant? If so, retrieve the constant value. 1500 QualType CT = Ctx.getCanonicalType(T); 1501 if (CT.isConstQualified()) { 1502 const Expr *Init = VD->getInit(); 1503 // Do the null check first, as we want to call 'IgnoreParenCasts'. 1504 if (Init) 1505 if (const IntegerLiteral *IL = 1506 dyn_cast<IntegerLiteral>(Init->IgnoreParenCasts())) { 1507 const nonloc::ConcreteInt &V = svalBuilder.makeIntVal(IL); 1508 return svalBuilder.evalCast(V, Init->getType(), IL->getType()); 1509 } 1510 } 1511 1512 if (const Optional<SVal> &V 1513 = getBindingForDerivedDefaultValue(B, MS, R, CT)) 1514 return V.getValue(); 1515 1516 return svalBuilder.getRegionValueSymbolVal(R); 1517 } 1518 1519 if (T->isIntegerType()) 1520 return svalBuilder.makeIntVal(0, T); 1521 if (T->isPointerType()) 1522 return svalBuilder.makeNull(); 1523 1524 return UnknownVal(); 1525 } 1526 1527 return UndefinedVal(); 1528} 1529 1530SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) { 1531 // All other values are symbolic. 1532 return svalBuilder.getRegionValueSymbolVal(R); 1533} 1534 1535static bool mayHaveLazyBinding(QualType Ty) { 1536 return Ty->isArrayType() || Ty->isStructureOrClassType(); 1537} 1538 1539SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B, 1540 const TypedValueRegion* R) { 1541 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl(); 1542 if (RD->field_empty()) 1543 return UnknownVal(); 1544 1545 // If we already have a lazy binding, don't create a new one, 1546 // unless the first field might have a lazy binding of its own. 1547 // (Right now we can't tell the difference.) 1548 QualType FirstFieldType = RD->field_begin()->getType(); 1549 if (!mayHaveLazyBinding(FirstFieldType)) { 1550 BindingKey K = BindingKey::Make(R, BindingKey::Default); 1551 if (const nonloc::LazyCompoundVal *V = 1552 dyn_cast_or_null<nonloc::LazyCompoundVal>(B.lookup(K))) { 1553 return *V; 1554 } 1555 } 1556 1557 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R); 1558} 1559 1560SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B, 1561 const TypedValueRegion * R) { 1562 const ConstantArrayType *Ty = Ctx.getAsConstantArrayType(R->getValueType()); 1563 assert(Ty && "Only constant array types can have compound bindings."); 1564 1565 // If we already have a lazy binding, don't create a new one, 1566 // unless the first element might have a lazy binding of its own. 1567 // (Right now we can't tell the difference.) 1568 if (!mayHaveLazyBinding(Ty->getElementType())) { 1569 BindingKey K = BindingKey::Make(R, BindingKey::Default); 1570 if (const nonloc::LazyCompoundVal *V = 1571 dyn_cast_or_null<nonloc::LazyCompoundVal>(B.lookup(K))) { 1572 return *V; 1573 } 1574 } 1575 1576 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R); 1577} 1578 1579bool RegionStoreManager::includedInBindings(Store store, 1580 const MemRegion *region) const { 1581 RegionBindingsRef B = getRegionBindings(store); 1582 region = region->getBaseRegion(); 1583 1584 // Quick path: if the base is the head of a cluster, the region is live. 1585 if (B.lookup(region)) 1586 return true; 1587 1588 // Slow path: if the region is the VALUE of any binding, it is live. 1589 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) { 1590 const ClusterBindings &Cluster = RI.getData(); 1591 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1592 CI != CE; ++CI) { 1593 const SVal &D = CI.getData(); 1594 if (const MemRegion *R = D.getAsRegion()) 1595 if (R->getBaseRegion() == region) 1596 return true; 1597 } 1598 } 1599 1600 return false; 1601} 1602 1603//===----------------------------------------------------------------------===// 1604// Binding values to regions. 1605//===----------------------------------------------------------------------===// 1606 1607StoreRef RegionStoreManager::killBinding(Store ST, Loc L) { 1608 if (isa<loc::MemRegionVal>(L)) 1609 if (const MemRegion* R = cast<loc::MemRegionVal>(L).getRegion()) 1610 return StoreRef(getRegionBindings(ST).removeBinding(R) 1611 .asImmutableMap() 1612 .getRootWithoutRetain(), 1613 *this); 1614 1615 return StoreRef(ST, *this); 1616} 1617 1618RegionBindingsRef 1619RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) { 1620 if (isa<loc::ConcreteInt>(L)) 1621 return B; 1622 1623 // If we get here, the location should be a region. 1624 const MemRegion *R = cast<loc::MemRegionVal>(L).getRegion(); 1625 1626 // Check if the region is a struct region. 1627 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) { 1628 QualType Ty = TR->getValueType(); 1629 if (Ty->isArrayType()) 1630 return bindArray(B, TR, V); 1631 if (Ty->isStructureOrClassType()) 1632 return bindStruct(B, TR, V); 1633 if (Ty->isVectorType()) 1634 return bindVector(B, TR, V); 1635 } 1636 1637 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 1638 // Binding directly to a symbolic region should be treated as binding 1639 // to element 0. 1640 QualType T = SR->getSymbol()->getType(); 1641 if (T->isAnyPointerType() || T->isReferenceType()) 1642 T = T->getPointeeType(); 1643 1644 R = GetElementZeroRegion(SR, T); 1645 } 1646 1647 // Clear out bindings that may overlap with this binding. 1648 RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R)); 1649 return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V); 1650} 1651 1652// FIXME: this method should be merged into Bind(). 1653StoreRef RegionStoreManager::bindCompoundLiteral(Store ST, 1654 const CompoundLiteralExpr *CL, 1655 const LocationContext *LC, 1656 SVal V) { 1657 return Bind(ST, loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)), V); 1658} 1659 1660RegionBindingsRef 1661RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B, 1662 const MemRegion *R, 1663 QualType T) { 1664 SVal V; 1665 1666 if (Loc::isLocType(T)) 1667 V = svalBuilder.makeNull(); 1668 else if (T->isIntegerType()) 1669 V = svalBuilder.makeZeroVal(T); 1670 else if (T->isStructureOrClassType() || T->isArrayType()) { 1671 // Set the default value to a zero constant when it is a structure 1672 // or array. The type doesn't really matter. 1673 V = svalBuilder.makeZeroVal(Ctx.IntTy); 1674 } 1675 else { 1676 // We can't represent values of this type, but we still need to set a value 1677 // to record that the region has been initialized. 1678 // If this assertion ever fires, a new case should be added above -- we 1679 // should know how to default-initialize any value we can symbolicate. 1680 assert(!SymbolManager::canSymbolicate(T) && "This type is representable"); 1681 V = UnknownVal(); 1682 } 1683 1684 return B.addBinding(R, BindingKey::Default, V); 1685} 1686 1687RegionBindingsRef 1688RegionStoreManager::bindArray(RegionBindingsConstRef B, 1689 const TypedValueRegion* R, 1690 SVal Init) { 1691 1692 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType())); 1693 QualType ElementTy = AT->getElementType(); 1694 Optional<uint64_t> Size; 1695 1696 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT)) 1697 Size = CAT->getSize().getZExtValue(); 1698 1699 // Check if the init expr is a string literal. 1700 if (loc::MemRegionVal *MRV = dyn_cast<loc::MemRegionVal>(&Init)) { 1701 const StringRegion *S = cast<StringRegion>(MRV->getRegion()); 1702 1703 // Treat the string as a lazy compound value. 1704 StoreRef store(B.asStore(), *this); 1705 nonloc::LazyCompoundVal LCV = 1706 cast<nonloc::LazyCompoundVal>(svalBuilder.makeLazyCompoundVal(store, S)); 1707 return bindAggregate(B, R, LCV); 1708 } 1709 1710 // Handle lazy compound values. 1711 if (isa<nonloc::LazyCompoundVal>(Init)) 1712 return bindAggregate(B, R, Init); 1713 1714 // Remaining case: explicit compound values. 1715 1716 if (Init.isUnknown()) 1717 return setImplicitDefaultValue(B, R, ElementTy); 1718 1719 nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(Init); 1720 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1721 uint64_t i = 0; 1722 1723 RegionBindingsRef NewB(B); 1724 1725 for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) { 1726 // The init list might be shorter than the array length. 1727 if (VI == VE) 1728 break; 1729 1730 const NonLoc &Idx = svalBuilder.makeArrayIndex(i); 1731 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx); 1732 1733 if (ElementTy->isStructureOrClassType()) 1734 NewB = bindStruct(NewB, ER, *VI); 1735 else if (ElementTy->isArrayType()) 1736 NewB = bindArray(NewB, ER, *VI); 1737 else 1738 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1739 } 1740 1741 // If the init list is shorter than the array length, set the 1742 // array default value. 1743 if (Size.hasValue() && i < Size.getValue()) 1744 NewB = setImplicitDefaultValue(NewB, R, ElementTy); 1745 1746 return NewB; 1747} 1748 1749RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B, 1750 const TypedValueRegion* R, 1751 SVal V) { 1752 QualType T = R->getValueType(); 1753 assert(T->isVectorType()); 1754 const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs. 1755 1756 // Handle lazy compound values and symbolic values. 1757 if (isa<nonloc::LazyCompoundVal>(V) || isa<nonloc::SymbolVal>(V)) 1758 return bindAggregate(B, R, V); 1759 1760 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1761 // that we are binding symbolic struct value. Kill the field values, and if 1762 // the value is symbolic go and bind it as a "default" binding. 1763 if (!isa<nonloc::CompoundVal>(V)) { 1764 return bindAggregate(B, R, UnknownVal()); 1765 } 1766 1767 QualType ElemType = VT->getElementType(); 1768 nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(V); 1769 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1770 unsigned index = 0, numElements = VT->getNumElements(); 1771 RegionBindingsRef NewB(B); 1772 1773 for ( ; index != numElements ; ++index) { 1774 if (VI == VE) 1775 break; 1776 1777 NonLoc Idx = svalBuilder.makeArrayIndex(index); 1778 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx); 1779 1780 if (ElemType->isArrayType()) 1781 NewB = bindArray(NewB, ER, *VI); 1782 else if (ElemType->isStructureOrClassType()) 1783 NewB = bindStruct(NewB, ER, *VI); 1784 else 1785 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1786 } 1787 return NewB; 1788} 1789 1790RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B, 1791 const TypedValueRegion* R, 1792 SVal V) { 1793 if (!Features.supportsFields()) 1794 return B; 1795 1796 QualType T = R->getValueType(); 1797 assert(T->isStructureOrClassType()); 1798 1799 const RecordType* RT = T->getAs<RecordType>(); 1800 RecordDecl *RD = RT->getDecl(); 1801 1802 if (!RD->isCompleteDefinition()) 1803 return B; 1804 1805 // Handle lazy compound values and symbolic values. 1806 if (isa<nonloc::LazyCompoundVal>(V) || isa<nonloc::SymbolVal>(V)) 1807 return bindAggregate(B, R, V); 1808 1809 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1810 // that we are binding symbolic struct value. Kill the field values, and if 1811 // the value is symbolic go and bind it as a "default" binding. 1812 if (V.isUnknown() || !isa<nonloc::CompoundVal>(V)) 1813 return bindAggregate(B, R, UnknownVal()); 1814 1815 nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(V); 1816 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1817 1818 RecordDecl::field_iterator FI, FE; 1819 RegionBindingsRef NewB(B); 1820 1821 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) { 1822 1823 if (VI == VE) 1824 break; 1825 1826 // Skip any unnamed bitfields to stay in sync with the initializers. 1827 if (FI->isUnnamedBitfield()) 1828 continue; 1829 1830 QualType FTy = FI->getType(); 1831 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R); 1832 1833 if (FTy->isArrayType()) 1834 NewB = bindArray(NewB, FR, *VI); 1835 else if (FTy->isStructureOrClassType()) 1836 NewB = bindStruct(NewB, FR, *VI); 1837 else 1838 NewB = bind(NewB, svalBuilder.makeLoc(FR), *VI); 1839 ++VI; 1840 } 1841 1842 // There may be fewer values in the initialize list than the fields of struct. 1843 if (FI != FE) { 1844 NewB = NewB.addBinding(R, BindingKey::Default, 1845 svalBuilder.makeIntVal(0, false)); 1846 } 1847 1848 return NewB; 1849} 1850 1851RegionBindingsRef 1852RegionStoreManager::bindAggregate(RegionBindingsConstRef B, 1853 const TypedRegion *R, 1854 SVal Val) { 1855 // Remove the old bindings, using 'R' as the root of all regions 1856 // we will invalidate. Then add the new binding. 1857 return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val); 1858} 1859 1860//===----------------------------------------------------------------------===// 1861// State pruning. 1862//===----------------------------------------------------------------------===// 1863 1864namespace { 1865class removeDeadBindingsWorker : 1866 public ClusterAnalysis<removeDeadBindingsWorker> { 1867 SmallVector<const SymbolicRegion*, 12> Postponed; 1868 SymbolReaper &SymReaper; 1869 const StackFrameContext *CurrentLCtx; 1870 1871public: 1872 removeDeadBindingsWorker(RegionStoreManager &rm, 1873 ProgramStateManager &stateMgr, 1874 RegionBindingsRef b, SymbolReaper &symReaper, 1875 const StackFrameContext *LCtx) 1876 : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b, 1877 /* includeGlobals = */ false), 1878 SymReaper(symReaper), CurrentLCtx(LCtx) {} 1879 1880 // Called by ClusterAnalysis. 1881 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C); 1882 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C); 1883 1884 bool UpdatePostponed(); 1885 void VisitBinding(SVal V); 1886}; 1887} 1888 1889void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR, 1890 const ClusterBindings &C) { 1891 1892 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) { 1893 if (SymReaper.isLive(VR)) 1894 AddToWorkList(baseR, &C); 1895 1896 return; 1897 } 1898 1899 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 1900 if (SymReaper.isLive(SR->getSymbol())) 1901 AddToWorkList(SR, &C); 1902 else 1903 Postponed.push_back(SR); 1904 1905 return; 1906 } 1907 1908 if (isa<NonStaticGlobalSpaceRegion>(baseR)) { 1909 AddToWorkList(baseR, &C); 1910 return; 1911 } 1912 1913 // CXXThisRegion in the current or parent location context is live. 1914 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) { 1915 const StackArgumentsSpaceRegion *StackReg = 1916 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion()); 1917 const StackFrameContext *RegCtx = StackReg->getStackFrame(); 1918 if (CurrentLCtx && 1919 (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))) 1920 AddToWorkList(TR, &C); 1921 } 1922} 1923 1924void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR, 1925 const ClusterBindings &C) { 1926 // Mark the symbol for any SymbolicRegion with live bindings as live itself. 1927 // This means we should continue to track that symbol. 1928 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR)) 1929 SymReaper.markLive(SymR->getSymbol()); 1930 1931 for (ClusterBindings::iterator I = C.begin(), E = C.end(); I != E; ++I) 1932 VisitBinding(I.getData()); 1933} 1934 1935void removeDeadBindingsWorker::VisitBinding(SVal V) { 1936 // Is it a LazyCompoundVal? All referenced regions are live as well. 1937 if (const nonloc::LazyCompoundVal *LCS = 1938 dyn_cast<nonloc::LazyCompoundVal>(&V)) { 1939 1940 const MemRegion *LazyR = LCS->getRegion(); 1941 RegionBindingsRef B = RM.getRegionBindings(LCS->getStore()); 1942 1943 // FIXME: This should not have to walk all bindings in the old store. 1944 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); 1945 RI != RE; ++RI){ 1946 const ClusterBindings &Cluster = RI.getData(); 1947 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1948 CI != CE; ++CI) { 1949 BindingKey K = CI.getKey(); 1950 if (const SubRegion *BaseR = dyn_cast<SubRegion>(K.getRegion())) { 1951 if (BaseR == LazyR) 1952 VisitBinding(CI.getData()); 1953 else if (K.hasSymbolicOffset() && BaseR->isSubRegionOf(LazyR)) 1954 VisitBinding(CI.getData()); 1955 } 1956 } 1957 } 1958 1959 return; 1960 } 1961 1962 // If V is a region, then add it to the worklist. 1963 if (const MemRegion *R = V.getAsRegion()) { 1964 AddToWorkList(R); 1965 1966 // All regions captured by a block are also live. 1967 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) { 1968 BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(), 1969 E = BR->referenced_vars_end(); 1970 for ( ; I != E; ++I) 1971 AddToWorkList(I.getCapturedRegion()); 1972 } 1973 } 1974 1975 1976 // Update the set of live symbols. 1977 for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end(); 1978 SI!=SE; ++SI) 1979 SymReaper.markLive(*SI); 1980} 1981 1982bool removeDeadBindingsWorker::UpdatePostponed() { 1983 // See if any postponed SymbolicRegions are actually live now, after 1984 // having done a scan. 1985 bool changed = false; 1986 1987 for (SmallVectorImpl<const SymbolicRegion*>::iterator 1988 I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) { 1989 if (const SymbolicRegion *SR = *I) { 1990 if (SymReaper.isLive(SR->getSymbol())) { 1991 changed |= AddToWorkList(SR); 1992 *I = NULL; 1993 } 1994 } 1995 } 1996 1997 return changed; 1998} 1999 2000StoreRef RegionStoreManager::removeDeadBindings(Store store, 2001 const StackFrameContext *LCtx, 2002 SymbolReaper& SymReaper) { 2003 RegionBindingsRef B = getRegionBindings(store); 2004 removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx); 2005 W.GenerateClusters(); 2006 2007 // Enqueue the region roots onto the worklist. 2008 for (SymbolReaper::region_iterator I = SymReaper.region_begin(), 2009 E = SymReaper.region_end(); I != E; ++I) { 2010 W.AddToWorkList(*I); 2011 } 2012 2013 do W.RunWorkList(); while (W.UpdatePostponed()); 2014 2015 // We have now scanned the store, marking reachable regions and symbols 2016 // as live. We now remove all the regions that are dead from the store 2017 // as well as update DSymbols with the set symbols that are now dead. 2018 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 2019 const MemRegion *Base = I.getKey(); 2020 2021 // If the cluster has been visited, we know the region has been marked. 2022 if (W.isVisited(Base)) 2023 continue; 2024 2025 // Remove the dead entry. 2026 B = B.remove(Base); 2027 2028 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base)) 2029 SymReaper.maybeDead(SymR->getSymbol()); 2030 2031 // Mark all non-live symbols that this binding references as dead. 2032 const ClusterBindings &Cluster = I.getData(); 2033 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 2034 CI != CE; ++CI) { 2035 SVal X = CI.getData(); 2036 SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end(); 2037 for (; SI != SE; ++SI) 2038 SymReaper.maybeDead(*SI); 2039 } 2040 } 2041 2042 return StoreRef(B.asStore(), *this); 2043} 2044 2045//===----------------------------------------------------------------------===// 2046// Utility methods. 2047//===----------------------------------------------------------------------===// 2048 2049void RegionStoreManager::print(Store store, raw_ostream &OS, 2050 const char* nl, const char *sep) { 2051 RegionBindingsRef B = getRegionBindings(store); 2052 OS << "Store (direct and default bindings), " 2053 << B.asStore() 2054 << " :" << nl; 2055 B.dump(OS, nl); 2056} 2057