RegionStore.cpp revision 11f0cae4bf4f62dcc706d33c1f795d460cd64816
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; 33 34//===----------------------------------------------------------------------===// 35// Representation of binding keys. 36//===----------------------------------------------------------------------===// 37 38namespace { 39class BindingKey { 40public: 41 enum Kind { Default = 0x0, Direct = 0x1 }; 42private: 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 } 63public: 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 109BindingKey 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 117namespace 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} // end llvm namespace 128 129void BindingKey::dump() const { 130 llvm::errs() << *this; 131} 132 133//===----------------------------------------------------------------------===// 134// Actual Store type. 135//===----------------------------------------------------------------------===// 136 137typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings; 138typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef; 139 140typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings> 141 RegionBindings; 142 143namespace { 144class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *, 145 ClusterBindings> { 146 ClusterBindings::Factory &CBFactory; 147public: 148 typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings> 149 ParentTy; 150 151 RegionBindingsRef(ClusterBindings::Factory &CBFactory, 152 const RegionBindings::TreeTy *T, 153 RegionBindings::TreeTy::Factory *F) 154 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F), 155 CBFactory(CBFactory) {} 156 157 RegionBindingsRef(const ParentTy &P, ClusterBindings::Factory &CBFactory) 158 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P), 159 CBFactory(CBFactory) {} 160 161 RegionBindingsRef add(key_type_ref K, data_type_ref D) const { 162 return RegionBindingsRef(static_cast<const ParentTy*>(this)->add(K, D), 163 CBFactory); 164 } 165 166 RegionBindingsRef remove(key_type_ref K) const { 167 return RegionBindingsRef(static_cast<const ParentTy*>(this)->remove(K), 168 CBFactory); 169 } 170 171 RegionBindingsRef addBinding(BindingKey K, SVal V) const; 172 173 RegionBindingsRef addBinding(const MemRegion *R, 174 BindingKey::Kind k, SVal V) const; 175 176 RegionBindingsRef &operator=(const RegionBindingsRef &X) { 177 *static_cast<ParentTy*>(this) = X; 178 return *this; 179 } 180 181 const SVal *lookup(BindingKey K) const; 182 const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const; 183 const ClusterBindings *lookup(const MemRegion *R) const { 184 return static_cast<const ParentTy*>(this)->lookup(R); 185 } 186 187 RegionBindingsRef removeBinding(BindingKey K); 188 189 RegionBindingsRef removeBinding(const MemRegion *R, 190 BindingKey::Kind k); 191 192 RegionBindingsRef removeBinding(const MemRegion *R) { 193 return removeBinding(R, BindingKey::Direct). 194 removeBinding(R, BindingKey::Default); 195 } 196 197 Optional<SVal> getDirectBinding(const MemRegion *R) const; 198 199 /// getDefaultBinding - Returns an SVal* representing an optional default 200 /// binding associated with a region and its subregions. 201 Optional<SVal> getDefaultBinding(const MemRegion *R) const; 202 203 /// Return the internal tree as a Store. 204 Store asStore() const { 205 return asImmutableMap().getRootWithoutRetain(); 206 } 207 208 void dump(raw_ostream &OS, const char *nl) const { 209 for (iterator I = begin(), E = end(); I != E; ++I) { 210 const ClusterBindings &Cluster = I.getData(); 211 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 212 CI != CE; ++CI) { 213 OS << ' ' << CI.getKey() << " : " << CI.getData() << nl; 214 } 215 OS << nl; 216 } 217 } 218 219 LLVM_ATTRIBUTE_USED void dump() const { 220 dump(llvm::errs(), "\n"); 221 } 222}; 223} // end anonymous namespace 224 225typedef const RegionBindingsRef& RegionBindingsConstRef; 226 227Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const { 228 if (const SVal *V = lookup(R, BindingKey::Direct)) 229 return *V; 230 return Optional<SVal>(); 231} 232 233Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const { 234 if (R->isBoundable()) 235 if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) 236 if (TR->getValueType()->isUnionType()) 237 return UnknownVal(); 238 if (const SVal *V = lookup(R, BindingKey::Default)) 239 return *V; 240 return Optional<SVal>(); 241} 242 243RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const { 244 const MemRegion *Base = K.getBaseRegion(); 245 246 const ClusterBindings *ExistingCluster = lookup(Base); 247 ClusterBindings Cluster = (ExistingCluster ? *ExistingCluster 248 : CBFactory.getEmptyMap()); 249 250 ClusterBindings NewCluster = CBFactory.add(Cluster, K, V); 251 return add(Base, NewCluster); 252} 253 254 255RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R, 256 BindingKey::Kind k, 257 SVal V) const { 258 return addBinding(BindingKey::Make(R, k), V); 259} 260 261const SVal *RegionBindingsRef::lookup(BindingKey K) const { 262 const ClusterBindings *Cluster = lookup(K.getBaseRegion()); 263 if (!Cluster) 264 return 0; 265 return Cluster->lookup(K); 266} 267 268const SVal *RegionBindingsRef::lookup(const MemRegion *R, 269 BindingKey::Kind k) const { 270 return lookup(BindingKey::Make(R, k)); 271} 272 273RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) { 274 const MemRegion *Base = K.getBaseRegion(); 275 const ClusterBindings *Cluster = lookup(Base); 276 if (!Cluster) 277 return *this; 278 279 ClusterBindings NewCluster = CBFactory.remove(*Cluster, K); 280 if (NewCluster.isEmpty()) 281 return remove(Base); 282 return add(Base, NewCluster); 283} 284 285RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R, 286 BindingKey::Kind k){ 287 return removeBinding(BindingKey::Make(R, k)); 288} 289 290//===----------------------------------------------------------------------===// 291// Fine-grained control of RegionStoreManager. 292//===----------------------------------------------------------------------===// 293 294namespace { 295struct minimal_features_tag {}; 296struct maximal_features_tag {}; 297 298class RegionStoreFeatures { 299 bool SupportsFields; 300public: 301 RegionStoreFeatures(minimal_features_tag) : 302 SupportsFields(false) {} 303 304 RegionStoreFeatures(maximal_features_tag) : 305 SupportsFields(true) {} 306 307 void enableFields(bool t) { SupportsFields = t; } 308 309 bool supportsFields() const { return SupportsFields; } 310}; 311} 312 313//===----------------------------------------------------------------------===// 314// Main RegionStore logic. 315//===----------------------------------------------------------------------===// 316 317namespace { 318 319class RegionStoreManager : public StoreManager { 320public: 321 const RegionStoreFeatures Features; 322 RegionBindings::Factory RBFactory; 323 mutable ClusterBindings::Factory CBFactory; 324 325 typedef std::vector<SVal> SValListTy; 326private: 327 typedef llvm::DenseMap<const LazyCompoundValData *, 328 SValListTy> LazyBindingsMapTy; 329 LazyBindingsMapTy LazyBindingsMap; 330 331public: 332 RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f) 333 : StoreManager(mgr), Features(f), 334 RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()) {} 335 336 337 /// setImplicitDefaultValue - Set the default binding for the provided 338 /// MemRegion to the value implicitly defined for compound literals when 339 /// the value is not specified. 340 RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B, 341 const MemRegion *R, QualType T); 342 343 /// ArrayToPointer - Emulates the "decay" of an array to a pointer 344 /// type. 'Array' represents the lvalue of the array being decayed 345 /// to a pointer, and the returned SVal represents the decayed 346 /// version of that lvalue (i.e., a pointer to the first element of 347 /// the array). This is called by ExprEngine when evaluating 348 /// casts from arrays to pointers. 349 SVal ArrayToPointer(Loc Array); 350 351 StoreRef getInitialStore(const LocationContext *InitLoc) { 352 return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this); 353 } 354 355 //===-------------------------------------------------------------------===// 356 // Binding values to regions. 357 //===-------------------------------------------------------------------===// 358 RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K, 359 const Expr *Ex, 360 unsigned Count, 361 const LocationContext *LCtx, 362 RegionBindingsRef B, 363 InvalidatedRegions *Invalidated); 364 365 StoreRef invalidateRegions(Store store, ArrayRef<const MemRegion *> Regions, 366 const Expr *E, unsigned Count, 367 const LocationContext *LCtx, 368 InvalidatedSymbols &IS, 369 const CallEvent *Call, 370 InvalidatedRegions *Invalidated); 371 372 bool scanReachableSymbols(Store S, const MemRegion *R, 373 ScanReachableSymbols &Callbacks); 374 375 RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B, 376 const SubRegion *R); 377 378public: // Part of public interface to class. 379 380 virtual StoreRef Bind(Store store, Loc LV, SVal V) { 381 return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this); 382 } 383 384 RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V); 385 386 // BindDefault is only used to initialize a region with a default value. 387 StoreRef BindDefault(Store store, const MemRegion *R, SVal V) { 388 RegionBindingsRef B = getRegionBindings(store); 389 assert(!B.lookup(R, BindingKey::Default)); 390 assert(!B.lookup(R, BindingKey::Direct)); 391 return StoreRef(B.addBinding(R, BindingKey::Default, V) 392 .asImmutableMap() 393 .getRootWithoutRetain(), *this); 394 } 395 396 /// \brief Create a new store that binds a value to a compound literal. 397 /// 398 /// \param ST The original store whose bindings are the basis for the new 399 /// store. 400 /// 401 /// \param CL The compound literal to bind (the binding key). 402 /// 403 /// \param LC The LocationContext for the binding. 404 /// 405 /// \param V The value to bind to the compound literal. 406 StoreRef bindCompoundLiteral(Store ST, 407 const CompoundLiteralExpr *CL, 408 const LocationContext *LC, SVal V); 409 410 /// BindStruct - Bind a compound value to a structure. 411 RegionBindingsRef bindStruct(RegionBindingsConstRef B, 412 const TypedValueRegion* R, SVal V); 413 414 /// BindVector - Bind a compound value to a vector. 415 RegionBindingsRef bindVector(RegionBindingsConstRef B, 416 const TypedValueRegion* R, SVal V); 417 418 RegionBindingsRef bindArray(RegionBindingsConstRef B, 419 const TypedValueRegion* R, 420 SVal V); 421 422 /// Clears out all bindings in the given region and assigns a new value 423 /// as a Default binding. 424 RegionBindingsRef bindAggregate(RegionBindingsConstRef B, 425 const TypedRegion *R, 426 SVal DefaultVal); 427 428 /// \brief Create a new store with the specified binding removed. 429 /// \param ST the original store, that is the basis for the new store. 430 /// \param L the location whose binding should be removed. 431 virtual StoreRef killBinding(Store ST, Loc L); 432 433 void incrementReferenceCount(Store store) { 434 getRegionBindings(store).manualRetain(); 435 } 436 437 /// If the StoreManager supports it, decrement the reference count of 438 /// the specified Store object. If the reference count hits 0, the memory 439 /// associated with the object is recycled. 440 void decrementReferenceCount(Store store) { 441 getRegionBindings(store).manualRelease(); 442 } 443 444 bool includedInBindings(Store store, const MemRegion *region) const; 445 446 /// \brief Return the value bound to specified location in a given state. 447 /// 448 /// The high level logic for this method is this: 449 /// getBinding (L) 450 /// if L has binding 451 /// return L's binding 452 /// else if L is in killset 453 /// return unknown 454 /// else 455 /// if L is on stack or heap 456 /// return undefined 457 /// else 458 /// return symbolic 459 virtual SVal getBinding(Store S, Loc L, QualType T) { 460 return getBinding(getRegionBindings(S), L, T); 461 } 462 463 SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType()); 464 465 SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R); 466 467 SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R); 468 469 SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R); 470 471 SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R); 472 473 SVal getBindingForLazySymbol(const TypedValueRegion *R); 474 475 SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 476 const TypedValueRegion *R, 477 QualType Ty, 478 const MemRegion *superR); 479 480 SVal getLazyBinding(const SubRegion *LazyBindingRegion, 481 RegionBindingsRef LazyBinding); 482 483 /// Get bindings for the values in a struct and return a CompoundVal, used 484 /// when doing struct copy: 485 /// struct s x, y; 486 /// x = y; 487 /// y's value is retrieved by this method. 488 SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R); 489 SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R); 490 NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R); 491 492 /// Used to lazily generate derived symbols for bindings that are defined 493 /// implicitly by default bindings in a super region. 494 Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 495 const MemRegion *superR, 496 const TypedValueRegion *R, 497 QualType Ty); 498 499 /// Get the state and region whose binding this region \p R corresponds to. 500 /// 501 /// If there is no lazy binding for \p R, the returned value will have a null 502 /// \c second. Note that a null pointer can represents a valid Store. 503 std::pair<Store, const SubRegion *> 504 findLazyBinding(RegionBindingsConstRef B, const SubRegion *R, 505 const SubRegion *originalRegion); 506 507 /// Returns the cached set of interesting SVals contained within a lazy 508 /// binding. 509 /// 510 /// The precise value of "interesting" is determined for the purposes of 511 /// RegionStore's internal analysis. It must always contain all regions and 512 /// symbols, but may omit constants and other kinds of SVal. 513 const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV); 514 515 //===------------------------------------------------------------------===// 516 // State pruning. 517 //===------------------------------------------------------------------===// 518 519 /// removeDeadBindings - Scans the RegionStore of 'state' for dead values. 520 /// It returns a new Store with these values removed. 521 StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, 522 SymbolReaper& SymReaper); 523 524 //===------------------------------------------------------------------===// 525 // Region "extents". 526 //===------------------------------------------------------------------===// 527 528 // FIXME: This method will soon be eliminated; see the note in Store.h. 529 DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state, 530 const MemRegion* R, QualType EleTy); 531 532 //===------------------------------------------------------------------===// 533 // Utility methods. 534 //===------------------------------------------------------------------===// 535 536 RegionBindingsRef getRegionBindings(Store store) const { 537 return RegionBindingsRef(CBFactory, 538 static_cast<const RegionBindings::TreeTy*>(store), 539 RBFactory.getTreeFactory()); 540 } 541 542 void print(Store store, raw_ostream &Out, const char* nl, 543 const char *sep); 544 545 void iterBindings(Store store, BindingsHandler& f) { 546 RegionBindingsRef B = getRegionBindings(store); 547 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 548 const ClusterBindings &Cluster = I.getData(); 549 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 550 CI != CE; ++CI) { 551 const BindingKey &K = CI.getKey(); 552 if (!K.isDirect()) 553 continue; 554 if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) { 555 // FIXME: Possibly incorporate the offset? 556 if (!f.HandleBinding(*this, store, R, CI.getData())) 557 return; 558 } 559 } 560 } 561 } 562}; 563 564} // end anonymous namespace 565 566//===----------------------------------------------------------------------===// 567// RegionStore creation. 568//===----------------------------------------------------------------------===// 569 570StoreManager *ento::CreateRegionStoreManager(ProgramStateManager& StMgr) { 571 RegionStoreFeatures F = maximal_features_tag(); 572 return new RegionStoreManager(StMgr, F); 573} 574 575StoreManager * 576ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) { 577 RegionStoreFeatures F = minimal_features_tag(); 578 F.enableFields(true); 579 return new RegionStoreManager(StMgr, F); 580} 581 582 583//===----------------------------------------------------------------------===// 584// Region Cluster analysis. 585//===----------------------------------------------------------------------===// 586 587namespace { 588template <typename DERIVED> 589class ClusterAnalysis { 590protected: 591 typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap; 592 typedef SmallVector<const MemRegion *, 10> WorkList; 593 594 llvm::SmallPtrSet<const ClusterBindings *, 16> Visited; 595 596 WorkList WL; 597 598 RegionStoreManager &RM; 599 ASTContext &Ctx; 600 SValBuilder &svalBuilder; 601 602 RegionBindingsRef B; 603 604 const bool includeGlobals; 605 606 const ClusterBindings *getCluster(const MemRegion *R) { 607 return B.lookup(R); 608 } 609 610public: 611 ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr, 612 RegionBindingsRef b, const bool includeGlobals) 613 : RM(rm), Ctx(StateMgr.getContext()), 614 svalBuilder(StateMgr.getSValBuilder()), 615 B(b), includeGlobals(includeGlobals) {} 616 617 RegionBindingsRef getRegionBindings() const { return B; } 618 619 bool isVisited(const MemRegion *R) { 620 return Visited.count(getCluster(R)); 621 } 622 623 void GenerateClusters() { 624 // Scan the entire set of bindings and record the region clusters. 625 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); 626 RI != RE; ++RI){ 627 const MemRegion *Base = RI.getKey(); 628 629 const ClusterBindings &Cluster = RI.getData(); 630 assert(!Cluster.isEmpty() && "Empty clusters should be removed"); 631 static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster); 632 633 if (includeGlobals) 634 if (isa<NonStaticGlobalSpaceRegion>(Base->getMemorySpace())) 635 AddToWorkList(Base, &Cluster); 636 } 637 } 638 639 bool AddToWorkList(const MemRegion *R, const ClusterBindings *C) { 640 if (C && !Visited.insert(C)) 641 return false; 642 WL.push_back(R); 643 return true; 644 } 645 646 bool AddToWorkList(const MemRegion *R) { 647 const MemRegion *baseR = R->getBaseRegion(); 648 return AddToWorkList(baseR, getCluster(baseR)); 649 } 650 651 void RunWorkList() { 652 while (!WL.empty()) { 653 const MemRegion *baseR = WL.pop_back_val(); 654 655 // First visit the cluster. 656 if (const ClusterBindings *Cluster = getCluster(baseR)) 657 static_cast<DERIVED*>(this)->VisitCluster(baseR, *Cluster); 658 659 // Next, visit the base region. 660 static_cast<DERIVED*>(this)->VisitBaseRegion(baseR); 661 } 662 } 663 664public: 665 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {} 666 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C) {} 667 void VisitBaseRegion(const MemRegion *baseR) {} 668}; 669} 670 671//===----------------------------------------------------------------------===// 672// Binding invalidation. 673//===----------------------------------------------------------------------===// 674 675bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R, 676 ScanReachableSymbols &Callbacks) { 677 assert(R == R->getBaseRegion() && "Should only be called for base regions"); 678 RegionBindingsRef B = getRegionBindings(S); 679 const ClusterBindings *Cluster = B.lookup(R); 680 681 if (!Cluster) 682 return true; 683 684 for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end(); 685 RI != RE; ++RI) { 686 if (!Callbacks.scan(RI.getData())) 687 return false; 688 } 689 690 return true; 691} 692 693static inline bool isUnionField(const FieldRegion *FR) { 694 return FR->getDecl()->getParent()->isUnion(); 695} 696 697typedef SmallVector<const FieldDecl *, 8> FieldVector; 698 699void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) { 700 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 701 702 const MemRegion *Base = K.getConcreteOffsetRegion(); 703 const MemRegion *R = K.getRegion(); 704 705 while (R != Base) { 706 if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) 707 if (!isUnionField(FR)) 708 Fields.push_back(FR->getDecl()); 709 710 R = cast<SubRegion>(R)->getSuperRegion(); 711 } 712} 713 714static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) { 715 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 716 717 if (Fields.empty()) 718 return true; 719 720 FieldVector FieldsInBindingKey; 721 getSymbolicOffsetFields(K, FieldsInBindingKey); 722 723 ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size(); 724 if (Delta >= 0) 725 return std::equal(FieldsInBindingKey.begin() + Delta, 726 FieldsInBindingKey.end(), 727 Fields.begin()); 728 else 729 return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(), 730 Fields.begin() - Delta); 731} 732 733/// Collects all keys in \p Cluster that may refer to bindings within \p Top. 734/// 735/// The \p IncludeAllDefaultBindings parameter specifies whether to include 736/// default bindings that may extend beyond \p Top itself, e.g. if \p Top is 737/// an aggregate within a larger aggregate with a default binding. 738static void collectSubRegionKeys(SmallVectorImpl<BindingKey> &Keys, 739 SValBuilder &SVB, 740 const ClusterBindings &Cluster, 741 const SubRegion *Top, BindingKey TopKey, 742 bool IncludeAllDefaultBindings) { 743 FieldVector FieldsInSymbolicSubregions; 744 if (TopKey.hasSymbolicOffset()) { 745 getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions); 746 Top = cast<SubRegion>(TopKey.getConcreteOffsetRegion()); 747 TopKey = BindingKey::Make(Top, BindingKey::Default); 748 } 749 750 // This assumes the region being invalidated is char-aligned. This isn't 751 // true for bitfields, but since bitfields have no subregions they shouldn't 752 // be using this function anyway. 753 uint64_t Length = UINT64_MAX; 754 SVal Extent = Top->getExtent(SVB); 755 if (Optional<nonloc::ConcreteInt> ExtentCI = 756 Extent.getAs<nonloc::ConcreteInt>()) { 757 const llvm::APSInt &ExtentInt = ExtentCI->getValue(); 758 assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned()); 759 // Extents are in bytes but region offsets are in bits. Be careful! 760 Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth(); 761 } 762 763 for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end(); 764 I != E; ++I) { 765 BindingKey NextKey = I.getKey(); 766 if (NextKey.getRegion() == TopKey.getRegion()) { 767 // FIXME: This doesn't catch the case where we're really invalidating a 768 // region with a symbolic offset. Example: 769 // R: points[i].y 770 // Next: points[0].x 771 772 if (NextKey.getOffset() > TopKey.getOffset() && 773 NextKey.getOffset() - TopKey.getOffset() < Length) { 774 // Case 1: The next binding is inside the region we're invalidating. 775 // Remove it. 776 Keys.push_back(NextKey); 777 778 } else if (NextKey.getOffset() == TopKey.getOffset()) { 779 // Case 2: The next binding is at the same offset as the region we're 780 // invalidating. In this case, we need to leave default bindings alone, 781 // since they may be providing a default value for a regions beyond what 782 // we're invalidating. 783 // FIXME: This is probably incorrect; consider invalidating an outer 784 // struct whose first field is bound to a LazyCompoundVal. 785 if (IncludeAllDefaultBindings || NextKey.isDirect()) 786 Keys.push_back(NextKey); 787 } 788 789 } else if (NextKey.hasSymbolicOffset()) { 790 const MemRegion *Base = NextKey.getConcreteOffsetRegion(); 791 if (Top->isSubRegionOf(Base)) { 792 // Case 3: The next key is symbolic and we just changed something within 793 // its concrete region. We don't know if the binding is still valid, so 794 // we'll be conservative and remove it. 795 if (IncludeAllDefaultBindings || NextKey.isDirect()) 796 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 797 Keys.push_back(NextKey); 798 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) { 799 // Case 4: The next key is symbolic, but we changed a known 800 // super-region. In this case the binding is certainly no longer valid. 801 if (Top == Base || BaseSR->isSubRegionOf(Top)) 802 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 803 Keys.push_back(NextKey); 804 } 805 } 806 } 807} 808 809static void collectSubRegionKeys(SmallVectorImpl<BindingKey> &Keys, 810 SValBuilder &SVB, 811 const ClusterBindings &Cluster, 812 const SubRegion *Top, 813 bool IncludeAllDefaultBindings) { 814 collectSubRegionKeys(Keys, SVB, Cluster, Top, 815 BindingKey::Make(Top, BindingKey::Default), 816 IncludeAllDefaultBindings); 817} 818 819RegionBindingsRef 820RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B, 821 const SubRegion *Top) { 822 BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default); 823 const MemRegion *ClusterHead = TopKey.getBaseRegion(); 824 if (Top == ClusterHead) { 825 // We can remove an entire cluster's bindings all in one go. 826 return B.remove(Top); 827 } 828 829 const ClusterBindings *Cluster = B.lookup(ClusterHead); 830 if (!Cluster) 831 return B; 832 833 SmallVector<BindingKey, 32> Keys; 834 collectSubRegionKeys(Keys, svalBuilder, *Cluster, Top, TopKey, 835 /*IncludeAllDefaultBindings=*/false); 836 837 ClusterBindingsRef Result(*Cluster, CBFactory); 838 for (SmallVectorImpl<BindingKey>::const_iterator I = Keys.begin(), 839 E = Keys.end(); 840 I != E; ++I) 841 Result = Result.remove(*I); 842 843 // If we're invalidating a region with a symbolic offset, we need to make sure 844 // we don't treat the base region as uninitialized anymore. 845 // FIXME: This isn't very precise; see the example in the loop. 846 if (TopKey.hasSymbolicOffset()) { 847 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 848 Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default), 849 UnknownVal()); 850 } 851 852 if (Result.isEmpty()) 853 return B.remove(ClusterHead); 854 return B.add(ClusterHead, Result.asImmutableMap()); 855} 856 857namespace { 858class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker> 859{ 860 const Expr *Ex; 861 unsigned Count; 862 const LocationContext *LCtx; 863 InvalidatedSymbols &IS; 864 StoreManager::InvalidatedRegions *Regions; 865public: 866 invalidateRegionsWorker(RegionStoreManager &rm, 867 ProgramStateManager &stateMgr, 868 RegionBindingsRef b, 869 const Expr *ex, unsigned count, 870 const LocationContext *lctx, 871 InvalidatedSymbols &is, 872 StoreManager::InvalidatedRegions *r, 873 bool includeGlobals) 874 : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, includeGlobals), 875 Ex(ex), Count(count), LCtx(lctx), IS(is), Regions(r) {} 876 877 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C); 878 void VisitBaseRegion(const MemRegion *baseR); 879 880private: 881 void VisitBinding(SVal V); 882}; 883} 884 885void invalidateRegionsWorker::VisitBinding(SVal V) { 886 // A symbol? Mark it touched by the invalidation. 887 if (SymbolRef Sym = V.getAsSymbol()) 888 IS.insert(Sym); 889 890 if (const MemRegion *R = V.getAsRegion()) { 891 AddToWorkList(R); 892 return; 893 } 894 895 // Is it a LazyCompoundVal? All references get invalidated as well. 896 if (Optional<nonloc::LazyCompoundVal> LCS = 897 V.getAs<nonloc::LazyCompoundVal>()) { 898 899 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 900 901 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 902 E = Vals.end(); 903 I != E; ++I) 904 VisitBinding(*I); 905 906 return; 907 } 908} 909 910void invalidateRegionsWorker::VisitCluster(const MemRegion *BaseR, 911 const ClusterBindings &C) { 912 for (ClusterBindings::iterator I = C.begin(), E = C.end(); I != E; ++I) 913 VisitBinding(I.getData()); 914 915 B = B.remove(BaseR); 916} 917 918void invalidateRegionsWorker::VisitBaseRegion(const MemRegion *baseR) { 919 // Symbolic region? Mark that symbol touched by the invalidation. 920 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) 921 IS.insert(SR->getSymbol()); 922 923 // BlockDataRegion? If so, invalidate captured variables that are passed 924 // by reference. 925 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) { 926 for (BlockDataRegion::referenced_vars_iterator 927 BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ; 928 BI != BE; ++BI) { 929 const VarRegion *VR = BI.getCapturedRegion(); 930 const VarDecl *VD = VR->getDecl(); 931 if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage()) { 932 AddToWorkList(VR); 933 } 934 else if (Loc::isLocType(VR->getValueType())) { 935 // Map the current bindings to a Store to retrieve the value 936 // of the binding. If that binding itself is a region, we should 937 // invalidate that region. This is because a block may capture 938 // a pointer value, but the thing pointed by that pointer may 939 // get invalidated. 940 SVal V = RM.getBinding(B, loc::MemRegionVal(VR)); 941 if (Optional<Loc> L = V.getAs<Loc>()) { 942 if (const MemRegion *LR = L->getAsRegion()) 943 AddToWorkList(LR); 944 } 945 } 946 } 947 return; 948 } 949 950 // Otherwise, we have a normal data region. Record that we touched the region. 951 if (Regions) 952 Regions->push_back(baseR); 953 954 if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) { 955 // Invalidate the region by setting its default value to 956 // conjured symbol. The type of the symbol is irrelavant. 957 DefinedOrUnknownSVal V = 958 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count); 959 B = B.addBinding(baseR, BindingKey::Default, V); 960 return; 961 } 962 963 if (!baseR->isBoundable()) 964 return; 965 966 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR); 967 QualType T = TR->getValueType(); 968 969 // Invalidate the binding. 970 if (T->isStructureOrClassType()) { 971 // Invalidate the region by setting its default value to 972 // conjured symbol. The type of the symbol is irrelavant. 973 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 974 Ctx.IntTy, Count); 975 B = B.addBinding(baseR, BindingKey::Default, V); 976 return; 977 } 978 979 if (const ArrayType *AT = Ctx.getAsArrayType(T)) { 980 // Set the default value of the array to conjured symbol. 981 DefinedOrUnknownSVal V = 982 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 983 AT->getElementType(), Count); 984 B = B.addBinding(baseR, BindingKey::Default, V); 985 return; 986 } 987 988 if (includeGlobals && 989 isa<NonStaticGlobalSpaceRegion>(baseR->getMemorySpace())) { 990 // If the region is a global and we are invalidating all globals, 991 // just erase the entry. This causes all globals to be lazily 992 // symbolicated from the same base symbol. 993 B = B.removeBinding(baseR); 994 return; 995 } 996 997 998 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 999 T,Count); 1000 assert(SymbolManager::canSymbolicate(T) || V.isUnknown()); 1001 B = B.addBinding(baseR, BindingKey::Direct, V); 1002} 1003 1004RegionBindingsRef 1005RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K, 1006 const Expr *Ex, 1007 unsigned Count, 1008 const LocationContext *LCtx, 1009 RegionBindingsRef B, 1010 InvalidatedRegions *Invalidated) { 1011 // Bind the globals memory space to a new symbol that we will use to derive 1012 // the bindings for all globals. 1013 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K); 1014 SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx, 1015 /* type does not matter */ Ctx.IntTy, 1016 Count); 1017 1018 B = B.removeBinding(GS) 1019 .addBinding(BindingKey::Make(GS, BindingKey::Default), V); 1020 1021 // Even if there are no bindings in the global scope, we still need to 1022 // record that we touched it. 1023 if (Invalidated) 1024 Invalidated->push_back(GS); 1025 1026 return B; 1027} 1028 1029StoreRef 1030RegionStoreManager::invalidateRegions(Store store, 1031 ArrayRef<const MemRegion *> Regions, 1032 const Expr *Ex, unsigned Count, 1033 const LocationContext *LCtx, 1034 InvalidatedSymbols &IS, 1035 const CallEvent *Call, 1036 InvalidatedRegions *Invalidated) { 1037 invalidateRegionsWorker W(*this, StateMgr, 1038 RegionStoreManager::getRegionBindings(store), 1039 Ex, Count, LCtx, IS, Invalidated, false); 1040 1041 // Scan the bindings and generate the clusters. 1042 W.GenerateClusters(); 1043 1044 // Add the regions to the worklist. 1045 for (ArrayRef<const MemRegion *>::iterator 1046 I = Regions.begin(), E = Regions.end(); I != E; ++I) 1047 W.AddToWorkList(*I); 1048 1049 W.RunWorkList(); 1050 1051 // Return the new bindings. 1052 RegionBindingsRef B = W.getRegionBindings(); 1053 1054 // For all globals which are not static nor immutable: determine which global 1055 // regions should be invalidated and invalidate them. 1056 // TODO: This could possibly be more precise with modules. 1057 // 1058 // System calls invalidate only system globals. 1059 if (Call && Call->isInSystemHeader()) { 1060 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1061 Ex, Count, LCtx, B, Invalidated); 1062 // Internal calls might invalidate both system and internal globals. 1063 } else { 1064 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1065 Ex, Count, LCtx, B, Invalidated); 1066 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind, 1067 Ex, Count, LCtx, B, Invalidated); 1068 } 1069 1070 return StoreRef(B.asStore(), *this); 1071} 1072 1073//===----------------------------------------------------------------------===// 1074// Extents for regions. 1075//===----------------------------------------------------------------------===// 1076 1077DefinedOrUnknownSVal 1078RegionStoreManager::getSizeInElements(ProgramStateRef state, 1079 const MemRegion *R, 1080 QualType EleTy) { 1081 SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder); 1082 const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size); 1083 if (!SizeInt) 1084 return UnknownVal(); 1085 1086 CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue()); 1087 1088 if (Ctx.getAsVariableArrayType(EleTy)) { 1089 // FIXME: We need to track extra state to properly record the size 1090 // of VLAs. Returning UnknownVal here, however, is a stop-gap so that 1091 // we don't have a divide-by-zero below. 1092 return UnknownVal(); 1093 } 1094 1095 CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy); 1096 1097 // If a variable is reinterpreted as a type that doesn't fit into a larger 1098 // type evenly, round it down. 1099 // This is a signed value, since it's used in arithmetic with signed indices. 1100 return svalBuilder.makeIntVal(RegionSize / EleSize, false); 1101} 1102 1103//===----------------------------------------------------------------------===// 1104// Location and region casting. 1105//===----------------------------------------------------------------------===// 1106 1107/// ArrayToPointer - Emulates the "decay" of an array to a pointer 1108/// type. 'Array' represents the lvalue of the array being decayed 1109/// to a pointer, and the returned SVal represents the decayed 1110/// version of that lvalue (i.e., a pointer to the first element of 1111/// the array). This is called by ExprEngine when evaluating casts 1112/// from arrays to pointers. 1113SVal RegionStoreManager::ArrayToPointer(Loc Array) { 1114 if (!Array.getAs<loc::MemRegionVal>()) 1115 return UnknownVal(); 1116 1117 const MemRegion* R = Array.castAs<loc::MemRegionVal>().getRegion(); 1118 const TypedValueRegion* ArrayR = dyn_cast<TypedValueRegion>(R); 1119 1120 if (!ArrayR) 1121 return UnknownVal(); 1122 1123 // Strip off typedefs from the ArrayRegion's ValueType. 1124 QualType T = ArrayR->getValueType().getDesugaredType(Ctx); 1125 const ArrayType *AT = cast<ArrayType>(T); 1126 T = AT->getElementType(); 1127 1128 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex(); 1129 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, ArrayR, Ctx)); 1130} 1131 1132//===----------------------------------------------------------------------===// 1133// Loading values from regions. 1134//===----------------------------------------------------------------------===// 1135 1136SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) { 1137 assert(!L.getAs<UnknownVal>() && "location unknown"); 1138 assert(!L.getAs<UndefinedVal>() && "location undefined"); 1139 1140 // For access to concrete addresses, return UnknownVal. Checks 1141 // for null dereferences (and similar errors) are done by checkers, not 1142 // the Store. 1143 // FIXME: We can consider lazily symbolicating such memory, but we really 1144 // should defer this when we can reason easily about symbolicating arrays 1145 // of bytes. 1146 if (L.getAs<loc::ConcreteInt>()) { 1147 return UnknownVal(); 1148 } 1149 if (!L.getAs<loc::MemRegionVal>()) { 1150 return UnknownVal(); 1151 } 1152 1153 const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion(); 1154 1155 if (isa<AllocaRegion>(MR) || 1156 isa<SymbolicRegion>(MR) || 1157 isa<CodeTextRegion>(MR)) { 1158 if (T.isNull()) { 1159 if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR)) 1160 T = TR->getLocationType(); 1161 else { 1162 const SymbolicRegion *SR = cast<SymbolicRegion>(MR); 1163 T = SR->getSymbol()->getType(); 1164 } 1165 } 1166 MR = GetElementZeroRegion(MR, T); 1167 } 1168 1169 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument 1170 // instead of 'Loc', and have the other Loc cases handled at a higher level. 1171 const TypedValueRegion *R = cast<TypedValueRegion>(MR); 1172 QualType RTy = R->getValueType(); 1173 1174 // FIXME: we do not yet model the parts of a complex type, so treat the 1175 // whole thing as "unknown". 1176 if (RTy->isAnyComplexType()) 1177 return UnknownVal(); 1178 1179 // FIXME: We should eventually handle funny addressing. e.g.: 1180 // 1181 // int x = ...; 1182 // int *p = &x; 1183 // char *q = (char*) p; 1184 // char c = *q; // returns the first byte of 'x'. 1185 // 1186 // Such funny addressing will occur due to layering of regions. 1187 if (RTy->isStructureOrClassType()) 1188 return getBindingForStruct(B, R); 1189 1190 // FIXME: Handle unions. 1191 if (RTy->isUnionType()) 1192 return UnknownVal(); 1193 1194 if (RTy->isArrayType()) { 1195 if (RTy->isConstantArrayType()) 1196 return getBindingForArray(B, R); 1197 else 1198 return UnknownVal(); 1199 } 1200 1201 // FIXME: handle Vector types. 1202 if (RTy->isVectorType()) 1203 return UnknownVal(); 1204 1205 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R)) 1206 return CastRetrievedVal(getBindingForField(B, FR), FR, T, false); 1207 1208 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) { 1209 // FIXME: Here we actually perform an implicit conversion from the loaded 1210 // value to the element type. Eventually we want to compose these values 1211 // more intelligently. For example, an 'element' can encompass multiple 1212 // bound regions (e.g., several bound bytes), or could be a subset of 1213 // a larger value. 1214 return CastRetrievedVal(getBindingForElement(B, ER), ER, T, false); 1215 } 1216 1217 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) { 1218 // FIXME: Here we actually perform an implicit conversion from the loaded 1219 // value to the ivar type. What we should model is stores to ivars 1220 // that blow past the extent of the ivar. If the address of the ivar is 1221 // reinterpretted, it is possible we stored a different value that could 1222 // fit within the ivar. Either we need to cast these when storing them 1223 // or reinterpret them lazily (as we do here). 1224 return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T, false); 1225 } 1226 1227 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { 1228 // FIXME: Here we actually perform an implicit conversion from the loaded 1229 // value to the variable type. What we should model is stores to variables 1230 // that blow past the extent of the variable. If the address of the 1231 // variable is reinterpretted, it is possible we stored a different value 1232 // that could fit within the variable. Either we need to cast these when 1233 // storing them or reinterpret them lazily (as we do here). 1234 return CastRetrievedVal(getBindingForVar(B, VR), VR, T, false); 1235 } 1236 1237 const SVal *V = B.lookup(R, BindingKey::Direct); 1238 1239 // Check if the region has a binding. 1240 if (V) 1241 return *V; 1242 1243 // The location does not have a bound value. This means that it has 1244 // the value it had upon its creation and/or entry to the analyzed 1245 // function/method. These are either symbolic values or 'undefined'. 1246 if (R->hasStackNonParametersStorage()) { 1247 // All stack variables are considered to have undefined values 1248 // upon creation. All heap allocated blocks are considered to 1249 // have undefined values as well unless they are explicitly bound 1250 // to specific values. 1251 return UndefinedVal(); 1252 } 1253 1254 // All other values are symbolic. 1255 return svalBuilder.getRegionValueSymbolVal(R); 1256} 1257 1258/// Checks to see if store \p B has a lazy binding for region \p R. 1259/// 1260/// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected 1261/// if there are additional bindings within \p R. 1262/// 1263/// Note that unlike RegionStoreManager::findLazyBinding, this will not search 1264/// for lazy bindings for super-regions of \p R. 1265static Optional<nonloc::LazyCompoundVal> 1266getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B, 1267 const SubRegion *R, bool AllowSubregionBindings) { 1268 Optional<SVal> V = B.getDefaultBinding(R); 1269 if (!V) 1270 return Optional<nonloc::LazyCompoundVal>(); 1271 1272 Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>(); 1273 if (!LCV) 1274 return Optional<nonloc::LazyCompoundVal>(); 1275 1276 // If the LCV is for a subregion, the types won't match, and we shouldn't 1277 // reuse the binding. Unfortuately we can only check this if the destination 1278 // region is a TypedValueRegion. 1279 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) { 1280 QualType RegionTy = TVR->getValueType(); 1281 QualType SourceRegionTy = LCV->getRegion()->getValueType(); 1282 if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy)) 1283 return Optional<nonloc::LazyCompoundVal>(); 1284 } 1285 1286 if (!AllowSubregionBindings) { 1287 // If there are any other bindings within this region, we shouldn't reuse 1288 // the top-level binding. 1289 SmallVector<BindingKey, 16> Keys; 1290 collectSubRegionKeys(Keys, SVB, *B.lookup(R->getBaseRegion()), R, 1291 /*IncludeAllDefaultBindings=*/true); 1292 if (Keys.size() > 1) 1293 return Optional<nonloc::LazyCompoundVal>(); 1294 } 1295 1296 return *LCV; 1297} 1298 1299 1300std::pair<Store, const SubRegion *> 1301RegionStoreManager::findLazyBinding(RegionBindingsConstRef B, 1302 const SubRegion *R, 1303 const SubRegion *originalRegion) { 1304 if (originalRegion != R) { 1305 if (Optional<nonloc::LazyCompoundVal> V = 1306 getExistingLazyBinding(svalBuilder, B, R, true)) 1307 return std::make_pair(V->getStore(), V->getRegion()); 1308 } 1309 1310 typedef std::pair<Store, const SubRegion *> StoreRegionPair; 1311 StoreRegionPair Result = StoreRegionPair(); 1312 1313 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 1314 Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()), 1315 originalRegion); 1316 1317 if (Result.second) 1318 Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second); 1319 1320 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) { 1321 Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()), 1322 originalRegion); 1323 1324 if (Result.second) 1325 Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second); 1326 1327 } else if (const CXXBaseObjectRegion *BaseReg = 1328 dyn_cast<CXXBaseObjectRegion>(R)) { 1329 // C++ base object region is another kind of region that we should blast 1330 // through to look for lazy compound value. It is like a field region. 1331 Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()), 1332 originalRegion); 1333 1334 if (Result.second) 1335 Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg, 1336 Result.second); 1337 } 1338 1339 return Result; 1340} 1341 1342SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B, 1343 const ElementRegion* R) { 1344 // We do not currently model bindings of the CompoundLiteralregion. 1345 if (isa<CompoundLiteralRegion>(R->getBaseRegion())) 1346 return UnknownVal(); 1347 1348 // Check if the region has a binding. 1349 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1350 return *V; 1351 1352 const MemRegion* superR = R->getSuperRegion(); 1353 1354 // Check if the region is an element region of a string literal. 1355 if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) { 1356 // FIXME: Handle loads from strings where the literal is treated as 1357 // an integer, e.g., *((unsigned int*)"hello") 1358 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType(); 1359 if (T != Ctx.getCanonicalType(R->getElementType())) 1360 return UnknownVal(); 1361 1362 const StringLiteral *Str = StrR->getStringLiteral(); 1363 SVal Idx = R->getIndex(); 1364 if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) { 1365 int64_t i = CI->getValue().getSExtValue(); 1366 // Abort on string underrun. This can be possible by arbitrary 1367 // clients of getBindingForElement(). 1368 if (i < 0) 1369 return UndefinedVal(); 1370 int64_t length = Str->getLength(); 1371 // Technically, only i == length is guaranteed to be null. 1372 // However, such overflows should be caught before reaching this point; 1373 // the only time such an access would be made is if a string literal was 1374 // used to initialize a larger array. 1375 char c = (i >= length) ? '\0' : Str->getCodeUnit(i); 1376 return svalBuilder.makeIntVal(c, T); 1377 } 1378 } 1379 1380 // Check for loads from a code text region. For such loads, just give up. 1381 if (isa<CodeTextRegion>(superR)) 1382 return UnknownVal(); 1383 1384 // Handle the case where we are indexing into a larger scalar object. 1385 // For example, this handles: 1386 // int x = ... 1387 // char *y = &x; 1388 // return *y; 1389 // FIXME: This is a hack, and doesn't do anything really intelligent yet. 1390 const RegionRawOffset &O = R->getAsArrayOffset(); 1391 1392 // If we cannot reason about the offset, return an unknown value. 1393 if (!O.getRegion()) 1394 return UnknownVal(); 1395 1396 if (const TypedValueRegion *baseR = 1397 dyn_cast_or_null<TypedValueRegion>(O.getRegion())) { 1398 QualType baseT = baseR->getValueType(); 1399 if (baseT->isScalarType()) { 1400 QualType elemT = R->getElementType(); 1401 if (elemT->isScalarType()) { 1402 if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) { 1403 if (const Optional<SVal> &V = B.getDirectBinding(superR)) { 1404 if (SymbolRef parentSym = V->getAsSymbol()) 1405 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1406 1407 if (V->isUnknownOrUndef()) 1408 return *V; 1409 // Other cases: give up. We are indexing into a larger object 1410 // that has some value, but we don't know how to handle that yet. 1411 return UnknownVal(); 1412 } 1413 } 1414 } 1415 } 1416 } 1417 return getBindingForFieldOrElementCommon(B, R, R->getElementType(), 1418 superR); 1419} 1420 1421SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B, 1422 const FieldRegion* R) { 1423 1424 // Check if the region has a binding. 1425 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1426 return *V; 1427 1428 QualType Ty = R->getValueType(); 1429 return getBindingForFieldOrElementCommon(B, R, Ty, R->getSuperRegion()); 1430} 1431 1432Optional<SVal> 1433RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 1434 const MemRegion *superR, 1435 const TypedValueRegion *R, 1436 QualType Ty) { 1437 1438 if (const Optional<SVal> &D = B.getDefaultBinding(superR)) { 1439 const SVal &val = D.getValue(); 1440 if (SymbolRef parentSym = val.getAsSymbol()) 1441 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1442 1443 if (val.isZeroConstant()) 1444 return svalBuilder.makeZeroVal(Ty); 1445 1446 if (val.isUnknownOrUndef()) 1447 return val; 1448 1449 // Lazy bindings are handled later. 1450 if (val.getAs<nonloc::LazyCompoundVal>()) 1451 return Optional<SVal>(); 1452 1453 llvm_unreachable("Unknown default value"); 1454 } 1455 1456 return Optional<SVal>(); 1457} 1458 1459SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion, 1460 RegionBindingsRef LazyBinding) { 1461 SVal Result; 1462 if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion)) 1463 Result = getBindingForElement(LazyBinding, ER); 1464 else 1465 Result = getBindingForField(LazyBinding, 1466 cast<FieldRegion>(LazyBindingRegion)); 1467 1468 // This is a hack to deal with RegionStore's inability to distinguish a 1469 // default value for /part/ of an aggregate from a default value for the 1470 // /entire/ aggregate. The most common case of this is when struct Outer 1471 // has as its first member a struct Inner, which is copied in from a stack 1472 // variable. In this case, even if the Outer's default value is symbolic, 0, 1473 // or unknown, it gets overridden by the Inner's default value of undefined. 1474 // 1475 // This is a general problem -- if the Inner is zero-initialized, the Outer 1476 // will now look zero-initialized. The proper way to solve this is with a 1477 // new version of RegionStore that tracks the extent of a binding as well 1478 // as the offset. 1479 // 1480 // This hack only takes care of the undefined case because that can very 1481 // quickly result in a warning. 1482 if (Result.isUndef()) 1483 Result = UnknownVal(); 1484 1485 return Result; 1486} 1487 1488SVal 1489RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 1490 const TypedValueRegion *R, 1491 QualType Ty, 1492 const MemRegion *superR) { 1493 1494 // At this point we have already checked in either getBindingForElement or 1495 // getBindingForField if 'R' has a direct binding. 1496 1497 // Lazy binding? 1498 Store lazyBindingStore = NULL; 1499 const SubRegion *lazyBindingRegion = NULL; 1500 llvm::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R); 1501 if (lazyBindingRegion) 1502 return getLazyBinding(lazyBindingRegion, 1503 getRegionBindings(lazyBindingStore)); 1504 1505 // Record whether or not we see a symbolic index. That can completely 1506 // be out of scope of our lookup. 1507 bool hasSymbolicIndex = false; 1508 1509 while (superR) { 1510 if (const Optional<SVal> &D = 1511 getBindingForDerivedDefaultValue(B, superR, R, Ty)) 1512 return *D; 1513 1514 if (const ElementRegion *ER = dyn_cast<ElementRegion>(superR)) { 1515 NonLoc index = ER->getIndex(); 1516 if (!index.isConstant()) 1517 hasSymbolicIndex = true; 1518 } 1519 1520 // If our super region is a field or element itself, walk up the region 1521 // hierarchy to see if there is a default value installed in an ancestor. 1522 if (const SubRegion *SR = dyn_cast<SubRegion>(superR)) { 1523 superR = SR->getSuperRegion(); 1524 continue; 1525 } 1526 break; 1527 } 1528 1529 if (R->hasStackNonParametersStorage()) { 1530 if (isa<ElementRegion>(R)) { 1531 // Currently we don't reason specially about Clang-style vectors. Check 1532 // if superR is a vector and if so return Unknown. 1533 if (const TypedValueRegion *typedSuperR = 1534 dyn_cast<TypedValueRegion>(superR)) { 1535 if (typedSuperR->getValueType()->isVectorType()) 1536 return UnknownVal(); 1537 } 1538 } 1539 1540 // FIXME: We also need to take ElementRegions with symbolic indexes into 1541 // account. This case handles both directly accessing an ElementRegion 1542 // with a symbolic offset, but also fields within an element with 1543 // a symbolic offset. 1544 if (hasSymbolicIndex) 1545 return UnknownVal(); 1546 1547 return UndefinedVal(); 1548 } 1549 1550 // All other values are symbolic. 1551 return svalBuilder.getRegionValueSymbolVal(R); 1552} 1553 1554SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B, 1555 const ObjCIvarRegion* R) { 1556 // Check if the region has a binding. 1557 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1558 return *V; 1559 1560 const MemRegion *superR = R->getSuperRegion(); 1561 1562 // Check if the super region has a default binding. 1563 if (const Optional<SVal> &V = B.getDefaultBinding(superR)) { 1564 if (SymbolRef parentSym = V->getAsSymbol()) 1565 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1566 1567 // Other cases: give up. 1568 return UnknownVal(); 1569 } 1570 1571 return getBindingForLazySymbol(R); 1572} 1573 1574static Optional<SVal> getConstValue(SValBuilder &SVB, const VarDecl *VD) { 1575 ASTContext &Ctx = SVB.getContext(); 1576 if (!VD->getType().isConstQualified()) 1577 return Optional<SVal>(); 1578 1579 const Expr *Init = VD->getInit(); 1580 if (!Init) 1581 return Optional<SVal>(); 1582 1583 llvm::APSInt Result; 1584 if (Init->EvaluateAsInt(Result, Ctx)) 1585 return SVB.makeIntVal(Result); 1586 1587 if (Init->isNullPointerConstant(Ctx, Expr::NPC_ValueDependentIsNotNull)) 1588 return SVB.makeNull(); 1589 1590 // FIXME: Handle other possible constant expressions. 1591 return Optional<SVal>(); 1592} 1593 1594SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B, 1595 const VarRegion *R) { 1596 1597 // Check if the region has a binding. 1598 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1599 return *V; 1600 1601 // Lazily derive a value for the VarRegion. 1602 const VarDecl *VD = R->getDecl(); 1603 const MemSpaceRegion *MS = R->getMemorySpace(); 1604 1605 // Arguments are always symbolic. 1606 if (isa<StackArgumentsSpaceRegion>(MS)) 1607 return svalBuilder.getRegionValueSymbolVal(R); 1608 1609 // Is 'VD' declared constant? If so, retrieve the constant value. 1610 if (Optional<SVal> V = getConstValue(svalBuilder, VD)) 1611 return *V; 1612 1613 // This must come after the check for constants because closure-captured 1614 // constant variables may appear in UnknownSpaceRegion. 1615 if (isa<UnknownSpaceRegion>(MS)) 1616 return svalBuilder.getRegionValueSymbolVal(R); 1617 1618 if (isa<GlobalsSpaceRegion>(MS)) { 1619 QualType T = VD->getType(); 1620 1621 // Function-scoped static variables are default-initialized to 0; if they 1622 // have an initializer, it would have been processed by now. 1623 if (isa<StaticGlobalSpaceRegion>(MS)) 1624 return svalBuilder.makeZeroVal(T); 1625 1626 if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) 1627 return V.getValue(); 1628 1629 return svalBuilder.getRegionValueSymbolVal(R); 1630 } 1631 1632 return UndefinedVal(); 1633} 1634 1635SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) { 1636 // All other values are symbolic. 1637 return svalBuilder.getRegionValueSymbolVal(R); 1638} 1639 1640const RegionStoreManager::SValListTy & 1641RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) { 1642 // First, check the cache. 1643 LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData()); 1644 if (I != LazyBindingsMap.end()) 1645 return I->second; 1646 1647 // If we don't have a list of values cached, start constructing it. 1648 SValListTy List; 1649 1650 const SubRegion *LazyR = LCV.getRegion(); 1651 RegionBindingsRef B = getRegionBindings(LCV.getStore()); 1652 1653 // If this region had /no/ bindings at the time, there are no interesting 1654 // values to return. 1655 const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion()); 1656 if (!Cluster) 1657 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1658 1659 SmallVector<BindingKey, 32> Keys; 1660 collectSubRegionKeys(Keys, svalBuilder, *Cluster, LazyR, 1661 /*IncludeAllDefaultBindings=*/true); 1662 for (SmallVectorImpl<BindingKey>::const_iterator I = Keys.begin(), 1663 E = Keys.end(); 1664 I != E; ++I) { 1665 SVal V = *Cluster->lookup(*I); 1666 if (V.isUnknownOrUndef() || V.isConstant()) 1667 continue; 1668 1669 if (Optional<nonloc::LazyCompoundVal> InnerLCV = 1670 V.getAs<nonloc::LazyCompoundVal>()) { 1671 const SValListTy &InnerList = getInterestingValues(*InnerLCV); 1672 List.insert(List.end(), InnerList.begin(), InnerList.end()); 1673 continue; 1674 } 1675 1676 List.push_back(V); 1677 } 1678 1679 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1680} 1681 1682NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B, 1683 const TypedValueRegion *R) { 1684 if (Optional<nonloc::LazyCompoundVal> V = 1685 getExistingLazyBinding(svalBuilder, B, R, false)) 1686 return *V; 1687 1688 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R); 1689} 1690 1691SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B, 1692 const TypedValueRegion *R) { 1693 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl(); 1694 if (RD->field_empty()) 1695 return UnknownVal(); 1696 1697 return createLazyBinding(B, R); 1698} 1699 1700SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B, 1701 const TypedValueRegion *R) { 1702 assert(Ctx.getAsConstantArrayType(R->getValueType()) && 1703 "Only constant array types can have compound bindings."); 1704 1705 return createLazyBinding(B, R); 1706} 1707 1708bool RegionStoreManager::includedInBindings(Store store, 1709 const MemRegion *region) const { 1710 RegionBindingsRef B = getRegionBindings(store); 1711 region = region->getBaseRegion(); 1712 1713 // Quick path: if the base is the head of a cluster, the region is live. 1714 if (B.lookup(region)) 1715 return true; 1716 1717 // Slow path: if the region is the VALUE of any binding, it is live. 1718 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) { 1719 const ClusterBindings &Cluster = RI.getData(); 1720 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1721 CI != CE; ++CI) { 1722 const SVal &D = CI.getData(); 1723 if (const MemRegion *R = D.getAsRegion()) 1724 if (R->getBaseRegion() == region) 1725 return true; 1726 } 1727 } 1728 1729 return false; 1730} 1731 1732//===----------------------------------------------------------------------===// 1733// Binding values to regions. 1734//===----------------------------------------------------------------------===// 1735 1736StoreRef RegionStoreManager::killBinding(Store ST, Loc L) { 1737 if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>()) 1738 if (const MemRegion* R = LV->getRegion()) 1739 return StoreRef(getRegionBindings(ST).removeBinding(R) 1740 .asImmutableMap() 1741 .getRootWithoutRetain(), 1742 *this); 1743 1744 return StoreRef(ST, *this); 1745} 1746 1747RegionBindingsRef 1748RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) { 1749 if (L.getAs<loc::ConcreteInt>()) 1750 return B; 1751 1752 // If we get here, the location should be a region. 1753 const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion(); 1754 1755 // Check if the region is a struct region. 1756 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) { 1757 QualType Ty = TR->getValueType(); 1758 if (Ty->isArrayType()) 1759 return bindArray(B, TR, V); 1760 if (Ty->isStructureOrClassType()) 1761 return bindStruct(B, TR, V); 1762 if (Ty->isVectorType()) 1763 return bindVector(B, TR, V); 1764 } 1765 1766 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 1767 // Binding directly to a symbolic region should be treated as binding 1768 // to element 0. 1769 QualType T = SR->getSymbol()->getType(); 1770 if (T->isAnyPointerType() || T->isReferenceType()) 1771 T = T->getPointeeType(); 1772 1773 R = GetElementZeroRegion(SR, T); 1774 } 1775 1776 // Clear out bindings that may overlap with this binding. 1777 RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R)); 1778 return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V); 1779} 1780 1781// FIXME: this method should be merged into Bind(). 1782StoreRef RegionStoreManager::bindCompoundLiteral(Store ST, 1783 const CompoundLiteralExpr *CL, 1784 const LocationContext *LC, 1785 SVal V) { 1786 return Bind(ST, loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)), V); 1787} 1788 1789RegionBindingsRef 1790RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B, 1791 const MemRegion *R, 1792 QualType T) { 1793 SVal V; 1794 1795 if (Loc::isLocType(T)) 1796 V = svalBuilder.makeNull(); 1797 else if (T->isIntegerType()) 1798 V = svalBuilder.makeZeroVal(T); 1799 else if (T->isStructureOrClassType() || T->isArrayType()) { 1800 // Set the default value to a zero constant when it is a structure 1801 // or array. The type doesn't really matter. 1802 V = svalBuilder.makeZeroVal(Ctx.IntTy); 1803 } 1804 else { 1805 // We can't represent values of this type, but we still need to set a value 1806 // to record that the region has been initialized. 1807 // If this assertion ever fires, a new case should be added above -- we 1808 // should know how to default-initialize any value we can symbolicate. 1809 assert(!SymbolManager::canSymbolicate(T) && "This type is representable"); 1810 V = UnknownVal(); 1811 } 1812 1813 return B.addBinding(R, BindingKey::Default, V); 1814} 1815 1816RegionBindingsRef 1817RegionStoreManager::bindArray(RegionBindingsConstRef B, 1818 const TypedValueRegion* R, 1819 SVal Init) { 1820 1821 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType())); 1822 QualType ElementTy = AT->getElementType(); 1823 Optional<uint64_t> Size; 1824 1825 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT)) 1826 Size = CAT->getSize().getZExtValue(); 1827 1828 // Check if the init expr is a string literal. 1829 if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) { 1830 const StringRegion *S = cast<StringRegion>(MRV->getRegion()); 1831 1832 // Treat the string as a lazy compound value. 1833 StoreRef store(B.asStore(), *this); 1834 nonloc::LazyCompoundVal LCV = svalBuilder.makeLazyCompoundVal(store, S) 1835 .castAs<nonloc::LazyCompoundVal>(); 1836 return bindAggregate(B, R, LCV); 1837 } 1838 1839 // Handle lazy compound values. 1840 if (Init.getAs<nonloc::LazyCompoundVal>()) 1841 return bindAggregate(B, R, Init); 1842 1843 // Remaining case: explicit compound values. 1844 1845 if (Init.isUnknown()) 1846 return setImplicitDefaultValue(B, R, ElementTy); 1847 1848 const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>(); 1849 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1850 uint64_t i = 0; 1851 1852 RegionBindingsRef NewB(B); 1853 1854 for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) { 1855 // The init list might be shorter than the array length. 1856 if (VI == VE) 1857 break; 1858 1859 const NonLoc &Idx = svalBuilder.makeArrayIndex(i); 1860 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx); 1861 1862 if (ElementTy->isStructureOrClassType()) 1863 NewB = bindStruct(NewB, ER, *VI); 1864 else if (ElementTy->isArrayType()) 1865 NewB = bindArray(NewB, ER, *VI); 1866 else 1867 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1868 } 1869 1870 // If the init list is shorter than the array length, set the 1871 // array default value. 1872 if (Size.hasValue() && i < Size.getValue()) 1873 NewB = setImplicitDefaultValue(NewB, R, ElementTy); 1874 1875 return NewB; 1876} 1877 1878RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B, 1879 const TypedValueRegion* R, 1880 SVal V) { 1881 QualType T = R->getValueType(); 1882 assert(T->isVectorType()); 1883 const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs. 1884 1885 // Handle lazy compound values and symbolic values. 1886 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 1887 return bindAggregate(B, R, V); 1888 1889 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1890 // that we are binding symbolic struct value. Kill the field values, and if 1891 // the value is symbolic go and bind it as a "default" binding. 1892 if (!V.getAs<nonloc::CompoundVal>()) { 1893 return bindAggregate(B, R, UnknownVal()); 1894 } 1895 1896 QualType ElemType = VT->getElementType(); 1897 nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>(); 1898 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1899 unsigned index = 0, numElements = VT->getNumElements(); 1900 RegionBindingsRef NewB(B); 1901 1902 for ( ; index != numElements ; ++index) { 1903 if (VI == VE) 1904 break; 1905 1906 NonLoc Idx = svalBuilder.makeArrayIndex(index); 1907 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx); 1908 1909 if (ElemType->isArrayType()) 1910 NewB = bindArray(NewB, ER, *VI); 1911 else if (ElemType->isStructureOrClassType()) 1912 NewB = bindStruct(NewB, ER, *VI); 1913 else 1914 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1915 } 1916 return NewB; 1917} 1918 1919RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B, 1920 const TypedValueRegion* R, 1921 SVal V) { 1922 if (!Features.supportsFields()) 1923 return B; 1924 1925 QualType T = R->getValueType(); 1926 assert(T->isStructureOrClassType()); 1927 1928 const RecordType* RT = T->getAs<RecordType>(); 1929 RecordDecl *RD = RT->getDecl(); 1930 1931 if (!RD->isCompleteDefinition()) 1932 return B; 1933 1934 // Handle lazy compound values and symbolic values. 1935 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 1936 return bindAggregate(B, R, V); 1937 1938 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1939 // that we are binding symbolic struct value. Kill the field values, and if 1940 // the value is symbolic go and bind it as a "default" binding. 1941 if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>()) 1942 return bindAggregate(B, R, UnknownVal()); 1943 1944 const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>(); 1945 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1946 1947 RecordDecl::field_iterator FI, FE; 1948 RegionBindingsRef NewB(B); 1949 1950 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) { 1951 1952 if (VI == VE) 1953 break; 1954 1955 // Skip any unnamed bitfields to stay in sync with the initializers. 1956 if (FI->isUnnamedBitfield()) 1957 continue; 1958 1959 QualType FTy = FI->getType(); 1960 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R); 1961 1962 if (FTy->isArrayType()) 1963 NewB = bindArray(NewB, FR, *VI); 1964 else if (FTy->isStructureOrClassType()) 1965 NewB = bindStruct(NewB, FR, *VI); 1966 else 1967 NewB = bind(NewB, svalBuilder.makeLoc(FR), *VI); 1968 ++VI; 1969 } 1970 1971 // There may be fewer values in the initialize list than the fields of struct. 1972 if (FI != FE) { 1973 NewB = NewB.addBinding(R, BindingKey::Default, 1974 svalBuilder.makeIntVal(0, false)); 1975 } 1976 1977 return NewB; 1978} 1979 1980RegionBindingsRef 1981RegionStoreManager::bindAggregate(RegionBindingsConstRef B, 1982 const TypedRegion *R, 1983 SVal Val) { 1984 // Remove the old bindings, using 'R' as the root of all regions 1985 // we will invalidate. Then add the new binding. 1986 return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val); 1987} 1988 1989//===----------------------------------------------------------------------===// 1990// State pruning. 1991//===----------------------------------------------------------------------===// 1992 1993namespace { 1994class removeDeadBindingsWorker : 1995 public ClusterAnalysis<removeDeadBindingsWorker> { 1996 SmallVector<const SymbolicRegion*, 12> Postponed; 1997 SymbolReaper &SymReaper; 1998 const StackFrameContext *CurrentLCtx; 1999 2000public: 2001 removeDeadBindingsWorker(RegionStoreManager &rm, 2002 ProgramStateManager &stateMgr, 2003 RegionBindingsRef b, SymbolReaper &symReaper, 2004 const StackFrameContext *LCtx) 2005 : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b, 2006 /* includeGlobals = */ false), 2007 SymReaper(symReaper), CurrentLCtx(LCtx) {} 2008 2009 // Called by ClusterAnalysis. 2010 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C); 2011 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C); 2012 2013 bool UpdatePostponed(); 2014 void VisitBinding(SVal V); 2015}; 2016} 2017 2018void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR, 2019 const ClusterBindings &C) { 2020 2021 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) { 2022 if (SymReaper.isLive(VR)) 2023 AddToWorkList(baseR, &C); 2024 2025 return; 2026 } 2027 2028 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 2029 if (SymReaper.isLive(SR->getSymbol())) 2030 AddToWorkList(SR, &C); 2031 else 2032 Postponed.push_back(SR); 2033 2034 return; 2035 } 2036 2037 if (isa<NonStaticGlobalSpaceRegion>(baseR)) { 2038 AddToWorkList(baseR, &C); 2039 return; 2040 } 2041 2042 // CXXThisRegion in the current or parent location context is live. 2043 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) { 2044 const StackArgumentsSpaceRegion *StackReg = 2045 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion()); 2046 const StackFrameContext *RegCtx = StackReg->getStackFrame(); 2047 if (CurrentLCtx && 2048 (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))) 2049 AddToWorkList(TR, &C); 2050 } 2051} 2052 2053void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR, 2054 const ClusterBindings &C) { 2055 // Mark the symbol for any SymbolicRegion with live bindings as live itself. 2056 // This means we should continue to track that symbol. 2057 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR)) 2058 SymReaper.markLive(SymR->getSymbol()); 2059 2060 for (ClusterBindings::iterator I = C.begin(), E = C.end(); I != E; ++I) 2061 VisitBinding(I.getData()); 2062} 2063 2064void removeDeadBindingsWorker::VisitBinding(SVal V) { 2065 // Is it a LazyCompoundVal? All referenced regions are live as well. 2066 if (Optional<nonloc::LazyCompoundVal> LCS = 2067 V.getAs<nonloc::LazyCompoundVal>()) { 2068 2069 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 2070 2071 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 2072 E = Vals.end(); 2073 I != E; ++I) 2074 VisitBinding(*I); 2075 2076 return; 2077 } 2078 2079 // If V is a region, then add it to the worklist. 2080 if (const MemRegion *R = V.getAsRegion()) { 2081 AddToWorkList(R); 2082 2083 // All regions captured by a block are also live. 2084 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) { 2085 BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(), 2086 E = BR->referenced_vars_end(); 2087 for ( ; I != E; ++I) 2088 AddToWorkList(I.getCapturedRegion()); 2089 } 2090 } 2091 2092 2093 // Update the set of live symbols. 2094 for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end(); 2095 SI!=SE; ++SI) 2096 SymReaper.markLive(*SI); 2097} 2098 2099bool removeDeadBindingsWorker::UpdatePostponed() { 2100 // See if any postponed SymbolicRegions are actually live now, after 2101 // having done a scan. 2102 bool changed = false; 2103 2104 for (SmallVectorImpl<const SymbolicRegion*>::iterator 2105 I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) { 2106 if (const SymbolicRegion *SR = *I) { 2107 if (SymReaper.isLive(SR->getSymbol())) { 2108 changed |= AddToWorkList(SR); 2109 *I = NULL; 2110 } 2111 } 2112 } 2113 2114 return changed; 2115} 2116 2117StoreRef RegionStoreManager::removeDeadBindings(Store store, 2118 const StackFrameContext *LCtx, 2119 SymbolReaper& SymReaper) { 2120 RegionBindingsRef B = getRegionBindings(store); 2121 removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx); 2122 W.GenerateClusters(); 2123 2124 // Enqueue the region roots onto the worklist. 2125 for (SymbolReaper::region_iterator I = SymReaper.region_begin(), 2126 E = SymReaper.region_end(); I != E; ++I) { 2127 W.AddToWorkList(*I); 2128 } 2129 2130 do W.RunWorkList(); while (W.UpdatePostponed()); 2131 2132 // We have now scanned the store, marking reachable regions and symbols 2133 // as live. We now remove all the regions that are dead from the store 2134 // as well as update DSymbols with the set symbols that are now dead. 2135 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 2136 const MemRegion *Base = I.getKey(); 2137 2138 // If the cluster has been visited, we know the region has been marked. 2139 if (W.isVisited(Base)) 2140 continue; 2141 2142 // Remove the dead entry. 2143 B = B.remove(Base); 2144 2145 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base)) 2146 SymReaper.maybeDead(SymR->getSymbol()); 2147 2148 // Mark all non-live symbols that this binding references as dead. 2149 const ClusterBindings &Cluster = I.getData(); 2150 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 2151 CI != CE; ++CI) { 2152 SVal X = CI.getData(); 2153 SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end(); 2154 for (; SI != SE; ++SI) 2155 SymReaper.maybeDead(*SI); 2156 } 2157 } 2158 2159 return StoreRef(B.asStore(), *this); 2160} 2161 2162//===----------------------------------------------------------------------===// 2163// Utility methods. 2164//===----------------------------------------------------------------------===// 2165 2166void RegionStoreManager::print(Store store, raw_ostream &OS, 2167 const char* nl, const char *sep) { 2168 RegionBindingsRef B = getRegionBindings(store); 2169 OS << "Store (direct and default bindings), " 2170 << B.asStore() 2171 << " :" << nl; 2172 B.dump(OS, nl); 2173} 2174