RegionStore.cpp revision df5f80f8a34e26a4fb77f48f858c7838426a0785
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 } 127 128 template <typename T> struct isPodLike; 129 template <> struct isPodLike<BindingKey> { 130 static const bool value = true; 131 }; 132} // end llvm namespace 133 134void BindingKey::dump() const { 135 llvm::errs() << *this; 136} 137 138//===----------------------------------------------------------------------===// 139// Actual Store type. 140//===----------------------------------------------------------------------===// 141 142typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings; 143typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef; 144typedef std::pair<BindingKey, SVal> BindingPair; 145 146typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings> 147 RegionBindings; 148 149namespace { 150class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *, 151 ClusterBindings> { 152 ClusterBindings::Factory &CBFactory; 153public: 154 typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings> 155 ParentTy; 156 157 RegionBindingsRef(ClusterBindings::Factory &CBFactory, 158 const RegionBindings::TreeTy *T, 159 RegionBindings::TreeTy::Factory *F) 160 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F), 161 CBFactory(CBFactory) {} 162 163 RegionBindingsRef(const ParentTy &P, ClusterBindings::Factory &CBFactory) 164 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P), 165 CBFactory(CBFactory) {} 166 167 RegionBindingsRef add(key_type_ref K, data_type_ref D) const { 168 return RegionBindingsRef(static_cast<const ParentTy*>(this)->add(K, D), 169 CBFactory); 170 } 171 172 RegionBindingsRef remove(key_type_ref K) const { 173 return RegionBindingsRef(static_cast<const ParentTy*>(this)->remove(K), 174 CBFactory); 175 } 176 177 RegionBindingsRef addBinding(BindingKey K, SVal V) const; 178 179 RegionBindingsRef addBinding(const MemRegion *R, 180 BindingKey::Kind k, SVal V) const; 181 182 RegionBindingsRef &operator=(const RegionBindingsRef &X) { 183 *static_cast<ParentTy*>(this) = X; 184 return *this; 185 } 186 187 const SVal *lookup(BindingKey K) const; 188 const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const; 189 const ClusterBindings *lookup(const MemRegion *R) const { 190 return static_cast<const ParentTy*>(this)->lookup(R); 191 } 192 193 RegionBindingsRef removeBinding(BindingKey K); 194 195 RegionBindingsRef removeBinding(const MemRegion *R, 196 BindingKey::Kind k); 197 198 RegionBindingsRef removeBinding(const MemRegion *R) { 199 return removeBinding(R, BindingKey::Direct). 200 removeBinding(R, BindingKey::Default); 201 } 202 203 Optional<SVal> getDirectBinding(const MemRegion *R) const; 204 205 /// getDefaultBinding - Returns an SVal* representing an optional default 206 /// binding associated with a region and its subregions. 207 Optional<SVal> getDefaultBinding(const MemRegion *R) const; 208 209 /// Return the internal tree as a Store. 210 Store asStore() const { 211 return asImmutableMap().getRootWithoutRetain(); 212 } 213 214 void dump(raw_ostream &OS, const char *nl) const { 215 for (iterator I = begin(), E = end(); I != E; ++I) { 216 const ClusterBindings &Cluster = I.getData(); 217 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 218 CI != CE; ++CI) { 219 OS << ' ' << CI.getKey() << " : " << CI.getData() << nl; 220 } 221 OS << nl; 222 } 223 } 224 225 LLVM_ATTRIBUTE_USED void dump() const { 226 dump(llvm::errs(), "\n"); 227 } 228}; 229} // end anonymous namespace 230 231typedef const RegionBindingsRef& RegionBindingsConstRef; 232 233Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const { 234 return Optional<SVal>::create(lookup(R, BindingKey::Direct)); 235} 236 237Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const { 238 if (R->isBoundable()) 239 if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) 240 if (TR->getValueType()->isUnionType()) 241 return UnknownVal(); 242 243 return Optional<SVal>::create(lookup(R, BindingKey::Default)); 244} 245 246RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const { 247 const MemRegion *Base = K.getBaseRegion(); 248 249 const ClusterBindings *ExistingCluster = lookup(Base); 250 ClusterBindings Cluster = (ExistingCluster ? *ExistingCluster 251 : CBFactory.getEmptyMap()); 252 253 ClusterBindings NewCluster = CBFactory.add(Cluster, K, V); 254 return add(Base, NewCluster); 255} 256 257 258RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R, 259 BindingKey::Kind k, 260 SVal V) const { 261 return addBinding(BindingKey::Make(R, k), V); 262} 263 264const SVal *RegionBindingsRef::lookup(BindingKey K) const { 265 const ClusterBindings *Cluster = lookup(K.getBaseRegion()); 266 if (!Cluster) 267 return 0; 268 return Cluster->lookup(K); 269} 270 271const SVal *RegionBindingsRef::lookup(const MemRegion *R, 272 BindingKey::Kind k) const { 273 return lookup(BindingKey::Make(R, k)); 274} 275 276RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) { 277 const MemRegion *Base = K.getBaseRegion(); 278 const ClusterBindings *Cluster = lookup(Base); 279 if (!Cluster) 280 return *this; 281 282 ClusterBindings NewCluster = CBFactory.remove(*Cluster, K); 283 if (NewCluster.isEmpty()) 284 return remove(Base); 285 return add(Base, NewCluster); 286} 287 288RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R, 289 BindingKey::Kind k){ 290 return removeBinding(BindingKey::Make(R, k)); 291} 292 293//===----------------------------------------------------------------------===// 294// Fine-grained control of RegionStoreManager. 295//===----------------------------------------------------------------------===// 296 297namespace { 298struct minimal_features_tag {}; 299struct maximal_features_tag {}; 300 301class RegionStoreFeatures { 302 bool SupportsFields; 303public: 304 RegionStoreFeatures(minimal_features_tag) : 305 SupportsFields(false) {} 306 307 RegionStoreFeatures(maximal_features_tag) : 308 SupportsFields(true) {} 309 310 void enableFields(bool t) { SupportsFields = t; } 311 312 bool supportsFields() const { return SupportsFields; } 313}; 314} 315 316//===----------------------------------------------------------------------===// 317// Main RegionStore logic. 318//===----------------------------------------------------------------------===// 319 320namespace { 321 322class RegionStoreManager : public StoreManager { 323public: 324 const RegionStoreFeatures Features; 325 RegionBindings::Factory RBFactory; 326 mutable ClusterBindings::Factory CBFactory; 327 328 typedef std::vector<SVal> SValListTy; 329private: 330 typedef llvm::DenseMap<const LazyCompoundValData *, 331 SValListTy> LazyBindingsMapTy; 332 LazyBindingsMapTy LazyBindingsMap; 333 334public: 335 RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f) 336 : StoreManager(mgr), Features(f), 337 RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()) {} 338 339 340 /// setImplicitDefaultValue - Set the default binding for the provided 341 /// MemRegion to the value implicitly defined for compound literals when 342 /// the value is not specified. 343 RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B, 344 const MemRegion *R, QualType T); 345 346 /// ArrayToPointer - Emulates the "decay" of an array to a pointer 347 /// type. 'Array' represents the lvalue of the array being decayed 348 /// to a pointer, and the returned SVal represents the decayed 349 /// version of that lvalue (i.e., a pointer to the first element of 350 /// the array). This is called by ExprEngine when evaluating 351 /// casts from arrays to pointers. 352 SVal ArrayToPointer(Loc Array); 353 354 StoreRef getInitialStore(const LocationContext *InitLoc) { 355 return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this); 356 } 357 358 //===-------------------------------------------------------------------===// 359 // Binding values to regions. 360 //===-------------------------------------------------------------------===// 361 RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K, 362 const Expr *Ex, 363 unsigned Count, 364 const LocationContext *LCtx, 365 RegionBindingsRef B, 366 InvalidatedRegions *Invalidated); 367 368 StoreRef invalidateRegions(Store store, ArrayRef<const MemRegion *> Regions, 369 const Expr *E, unsigned Count, 370 const LocationContext *LCtx, 371 InvalidatedSymbols &IS, 372 const CallEvent *Call, 373 ArrayRef<const MemRegion *> ConstRegions, 374 InvalidatedRegions *Invalidated); 375 376 bool scanReachableSymbols(Store S, const MemRegion *R, 377 ScanReachableSymbols &Callbacks); 378 379 RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B, 380 const SubRegion *R); 381 382public: // Part of public interface to class. 383 384 virtual StoreRef Bind(Store store, Loc LV, SVal V) { 385 return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this); 386 } 387 388 RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V); 389 390 // BindDefault is only used to initialize a region with a default value. 391 StoreRef BindDefault(Store store, const MemRegion *R, SVal V) { 392 RegionBindingsRef B = getRegionBindings(store); 393 assert(!B.lookup(R, BindingKey::Default)); 394 assert(!B.lookup(R, BindingKey::Direct)); 395 return StoreRef(B.addBinding(R, BindingKey::Default, V) 396 .asImmutableMap() 397 .getRootWithoutRetain(), *this); 398 } 399 400 /// \brief Create a new store that binds a value to a compound literal. 401 /// 402 /// \param ST The original store whose bindings are the basis for the new 403 /// store. 404 /// 405 /// \param CL The compound literal to bind (the binding key). 406 /// 407 /// \param LC The LocationContext for the binding. 408 /// 409 /// \param V The value to bind to the compound literal. 410 StoreRef bindCompoundLiteral(Store ST, 411 const CompoundLiteralExpr *CL, 412 const LocationContext *LC, SVal V); 413 414 /// BindStruct - Bind a compound value to a structure. 415 RegionBindingsRef bindStruct(RegionBindingsConstRef B, 416 const TypedValueRegion* R, SVal V); 417 418 /// BindVector - Bind a compound value to a vector. 419 RegionBindingsRef bindVector(RegionBindingsConstRef B, 420 const TypedValueRegion* R, SVal V); 421 422 RegionBindingsRef bindArray(RegionBindingsConstRef B, 423 const TypedValueRegion* R, 424 SVal V); 425 426 /// Clears out all bindings in the given region and assigns a new value 427 /// as a Default binding. 428 RegionBindingsRef bindAggregate(RegionBindingsConstRef B, 429 const TypedRegion *R, 430 SVal DefaultVal); 431 432 /// \brief Create a new store with the specified binding removed. 433 /// \param ST the original store, that is the basis for the new store. 434 /// \param L the location whose binding should be removed. 435 virtual StoreRef killBinding(Store ST, Loc L); 436 437 void incrementReferenceCount(Store store) { 438 getRegionBindings(store).manualRetain(); 439 } 440 441 /// If the StoreManager supports it, decrement the reference count of 442 /// the specified Store object. If the reference count hits 0, the memory 443 /// associated with the object is recycled. 444 void decrementReferenceCount(Store store) { 445 getRegionBindings(store).manualRelease(); 446 } 447 448 bool includedInBindings(Store store, const MemRegion *region) const; 449 450 /// \brief Return the value bound to specified location in a given state. 451 /// 452 /// The high level logic for this method is this: 453 /// getBinding (L) 454 /// if L has binding 455 /// return L's binding 456 /// else if L is in killset 457 /// return unknown 458 /// else 459 /// if L is on stack or heap 460 /// return undefined 461 /// else 462 /// return symbolic 463 virtual SVal getBinding(Store S, Loc L, QualType T) { 464 return getBinding(getRegionBindings(S), L, T); 465 } 466 467 SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType()); 468 469 SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R); 470 471 SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R); 472 473 SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R); 474 475 SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R); 476 477 SVal getBindingForLazySymbol(const TypedValueRegion *R); 478 479 SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 480 const TypedValueRegion *R, 481 QualType Ty, 482 const MemRegion *superR); 483 484 SVal getLazyBinding(const SubRegion *LazyBindingRegion, 485 RegionBindingsRef LazyBinding); 486 487 /// Get bindings for the values in a struct and return a CompoundVal, used 488 /// when doing struct copy: 489 /// struct s x, y; 490 /// x = y; 491 /// y's value is retrieved by this method. 492 SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R); 493 SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R); 494 NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R); 495 496 /// Used to lazily generate derived symbols for bindings that are defined 497 /// implicitly by default bindings in a super region. 498 /// 499 /// Note that callers may need to specially handle LazyCompoundVals, which 500 /// are returned as is in case the caller needs to treat them differently. 501 Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 502 const MemRegion *superR, 503 const TypedValueRegion *R, 504 QualType Ty); 505 506 /// Get the state and region whose binding this region \p R corresponds to. 507 /// 508 /// If there is no lazy binding for \p R, the returned value will have a null 509 /// \c second. Note that a null pointer can represents a valid Store. 510 std::pair<Store, const SubRegion *> 511 findLazyBinding(RegionBindingsConstRef B, const SubRegion *R, 512 const SubRegion *originalRegion); 513 514 /// Returns the cached set of interesting SVals contained within a lazy 515 /// binding. 516 /// 517 /// The precise value of "interesting" is determined for the purposes of 518 /// RegionStore's internal analysis. It must always contain all regions and 519 /// symbols, but may omit constants and other kinds of SVal. 520 const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV); 521 522 //===------------------------------------------------------------------===// 523 // State pruning. 524 //===------------------------------------------------------------------===// 525 526 /// removeDeadBindings - Scans the RegionStore of 'state' for dead values. 527 /// It returns a new Store with these values removed. 528 StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, 529 SymbolReaper& SymReaper); 530 531 //===------------------------------------------------------------------===// 532 // Region "extents". 533 //===------------------------------------------------------------------===// 534 535 // FIXME: This method will soon be eliminated; see the note in Store.h. 536 DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state, 537 const MemRegion* R, QualType EleTy); 538 539 //===------------------------------------------------------------------===// 540 // Utility methods. 541 //===------------------------------------------------------------------===// 542 543 RegionBindingsRef getRegionBindings(Store store) const { 544 return RegionBindingsRef(CBFactory, 545 static_cast<const RegionBindings::TreeTy*>(store), 546 RBFactory.getTreeFactory()); 547 } 548 549 void print(Store store, raw_ostream &Out, const char* nl, 550 const char *sep); 551 552 void iterBindings(Store store, BindingsHandler& f) { 553 RegionBindingsRef B = getRegionBindings(store); 554 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 555 const ClusterBindings &Cluster = I.getData(); 556 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 557 CI != CE; ++CI) { 558 const BindingKey &K = CI.getKey(); 559 if (!K.isDirect()) 560 continue; 561 if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) { 562 // FIXME: Possibly incorporate the offset? 563 if (!f.HandleBinding(*this, store, R, CI.getData())) 564 return; 565 } 566 } 567 } 568 } 569}; 570 571} // end anonymous namespace 572 573//===----------------------------------------------------------------------===// 574// RegionStore creation. 575//===----------------------------------------------------------------------===// 576 577StoreManager *ento::CreateRegionStoreManager(ProgramStateManager& StMgr) { 578 RegionStoreFeatures F = maximal_features_tag(); 579 return new RegionStoreManager(StMgr, F); 580} 581 582StoreManager * 583ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) { 584 RegionStoreFeatures F = minimal_features_tag(); 585 F.enableFields(true); 586 return new RegionStoreManager(StMgr, F); 587} 588 589 590//===----------------------------------------------------------------------===// 591// Region Cluster analysis. 592//===----------------------------------------------------------------------===// 593 594namespace { 595template <typename DERIVED> 596class ClusterAnalysis { 597protected: 598 typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap; 599 typedef llvm::PointerIntPair<const MemRegion *, 1, bool> WorkListElement; 600 typedef SmallVector<WorkListElement, 10> WorkList; 601 602 llvm::SmallPtrSet<const ClusterBindings *, 16> Visited; 603 604 WorkList WL; 605 606 RegionStoreManager &RM; 607 ASTContext &Ctx; 608 SValBuilder &svalBuilder; 609 610 RegionBindingsRef B; 611 612 const bool includeGlobals; 613 614 const ClusterBindings *getCluster(const MemRegion *R) { 615 return B.lookup(R); 616 } 617 618public: 619 ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr, 620 RegionBindingsRef b, const bool includeGlobals) 621 : RM(rm), Ctx(StateMgr.getContext()), 622 svalBuilder(StateMgr.getSValBuilder()), 623 B(b), includeGlobals(includeGlobals) {} 624 625 RegionBindingsRef getRegionBindings() const { return B; } 626 627 bool isVisited(const MemRegion *R) { 628 return Visited.count(getCluster(R)); 629 } 630 631 void GenerateClusters() { 632 // Scan the entire set of bindings and record the region clusters. 633 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); 634 RI != RE; ++RI){ 635 const MemRegion *Base = RI.getKey(); 636 637 const ClusterBindings &Cluster = RI.getData(); 638 assert(!Cluster.isEmpty() && "Empty clusters should be removed"); 639 static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster); 640 641 if (includeGlobals) 642 if (isa<NonStaticGlobalSpaceRegion>(Base->getMemorySpace())) 643 AddToWorkList(Base, &Cluster); 644 } 645 } 646 647 bool AddToWorkList(WorkListElement E, const ClusterBindings *C) { 648 if (C && !Visited.insert(C)) 649 return false; 650 WL.push_back(E); 651 return true; 652 } 653 654 bool AddToWorkList(const MemRegion *R, bool Flag = false) { 655 const MemRegion *BaseR = R->getBaseRegion(); 656 return AddToWorkList(WorkListElement(BaseR, Flag), getCluster(BaseR)); 657 } 658 659 void RunWorkList() { 660 while (!WL.empty()) { 661 WorkListElement E = WL.pop_back_val(); 662 const MemRegion *BaseR = E.getPointer(); 663 664 static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR), 665 E.getInt()); 666 } 667 } 668 669 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {} 670 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {} 671 672 void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C, 673 bool Flag) { 674 static_cast<DERIVED*>(this)->VisitCluster(BaseR, C); 675 } 676}; 677} 678 679//===----------------------------------------------------------------------===// 680// Binding invalidation. 681//===----------------------------------------------------------------------===// 682 683bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R, 684 ScanReachableSymbols &Callbacks) { 685 assert(R == R->getBaseRegion() && "Should only be called for base regions"); 686 RegionBindingsRef B = getRegionBindings(S); 687 const ClusterBindings *Cluster = B.lookup(R); 688 689 if (!Cluster) 690 return true; 691 692 for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end(); 693 RI != RE; ++RI) { 694 if (!Callbacks.scan(RI.getData())) 695 return false; 696 } 697 698 return true; 699} 700 701static inline bool isUnionField(const FieldRegion *FR) { 702 return FR->getDecl()->getParent()->isUnion(); 703} 704 705typedef SmallVector<const FieldDecl *, 8> FieldVector; 706 707void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) { 708 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 709 710 const MemRegion *Base = K.getConcreteOffsetRegion(); 711 const MemRegion *R = K.getRegion(); 712 713 while (R != Base) { 714 if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) 715 if (!isUnionField(FR)) 716 Fields.push_back(FR->getDecl()); 717 718 R = cast<SubRegion>(R)->getSuperRegion(); 719 } 720} 721 722static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) { 723 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 724 725 if (Fields.empty()) 726 return true; 727 728 FieldVector FieldsInBindingKey; 729 getSymbolicOffsetFields(K, FieldsInBindingKey); 730 731 ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size(); 732 if (Delta >= 0) 733 return std::equal(FieldsInBindingKey.begin() + Delta, 734 FieldsInBindingKey.end(), 735 Fields.begin()); 736 else 737 return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(), 738 Fields.begin() - Delta); 739} 740 741/// Collects all bindings in \p Cluster that may refer to bindings within 742/// \p Top. 743/// 744/// Each binding is a pair whose \c first is the key (a BindingKey) and whose 745/// \c second is the value (an SVal). 746/// 747/// The \p IncludeAllDefaultBindings parameter specifies whether to include 748/// default bindings that may extend beyond \p Top itself, e.g. if \p Top is 749/// an aggregate within a larger aggregate with a default binding. 750static void 751collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 752 SValBuilder &SVB, const ClusterBindings &Cluster, 753 const SubRegion *Top, BindingKey TopKey, 754 bool IncludeAllDefaultBindings) { 755 FieldVector FieldsInSymbolicSubregions; 756 if (TopKey.hasSymbolicOffset()) { 757 getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions); 758 Top = cast<SubRegion>(TopKey.getConcreteOffsetRegion()); 759 TopKey = BindingKey::Make(Top, BindingKey::Default); 760 } 761 762 // Find the length (in bits) of the region being invalidated. 763 uint64_t Length = UINT64_MAX; 764 SVal Extent = Top->getExtent(SVB); 765 if (Optional<nonloc::ConcreteInt> ExtentCI = 766 Extent.getAs<nonloc::ConcreteInt>()) { 767 const llvm::APSInt &ExtentInt = ExtentCI->getValue(); 768 assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned()); 769 // Extents are in bytes but region offsets are in bits. Be careful! 770 Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth(); 771 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) { 772 if (FR->getDecl()->isBitField()) 773 Length = FR->getDecl()->getBitWidthValue(SVB.getContext()); 774 } 775 776 for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end(); 777 I != E; ++I) { 778 BindingKey NextKey = I.getKey(); 779 if (NextKey.getRegion() == TopKey.getRegion()) { 780 // FIXME: This doesn't catch the case where we're really invalidating a 781 // region with a symbolic offset. Example: 782 // R: points[i].y 783 // Next: points[0].x 784 785 if (NextKey.getOffset() > TopKey.getOffset() && 786 NextKey.getOffset() - TopKey.getOffset() < Length) { 787 // Case 1: The next binding is inside the region we're invalidating. 788 // Include it. 789 Bindings.push_back(*I); 790 791 } else if (NextKey.getOffset() == TopKey.getOffset()) { 792 // Case 2: The next binding is at the same offset as the region we're 793 // invalidating. In this case, we need to leave default bindings alone, 794 // since they may be providing a default value for a regions beyond what 795 // we're invalidating. 796 // FIXME: This is probably incorrect; consider invalidating an outer 797 // struct whose first field is bound to a LazyCompoundVal. 798 if (IncludeAllDefaultBindings || NextKey.isDirect()) 799 Bindings.push_back(*I); 800 } 801 802 } else if (NextKey.hasSymbolicOffset()) { 803 const MemRegion *Base = NextKey.getConcreteOffsetRegion(); 804 if (Top->isSubRegionOf(Base)) { 805 // Case 3: The next key is symbolic and we just changed something within 806 // its concrete region. We don't know if the binding is still valid, so 807 // we'll be conservative and include it. 808 if (IncludeAllDefaultBindings || NextKey.isDirect()) 809 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 810 Bindings.push_back(*I); 811 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) { 812 // Case 4: The next key is symbolic, but we changed a known 813 // super-region. In this case the binding is certainly included. 814 if (Top == Base || BaseSR->isSubRegionOf(Top)) 815 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 816 Bindings.push_back(*I); 817 } 818 } 819 } 820} 821 822static void 823collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 824 SValBuilder &SVB, const ClusterBindings &Cluster, 825 const SubRegion *Top, bool IncludeAllDefaultBindings) { 826 collectSubRegionBindings(Bindings, SVB, Cluster, Top, 827 BindingKey::Make(Top, BindingKey::Default), 828 IncludeAllDefaultBindings); 829} 830 831RegionBindingsRef 832RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B, 833 const SubRegion *Top) { 834 BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default); 835 const MemRegion *ClusterHead = TopKey.getBaseRegion(); 836 837 if (Top == ClusterHead) { 838 // We can remove an entire cluster's bindings all in one go. 839 return B.remove(Top); 840 } 841 842 const ClusterBindings *Cluster = B.lookup(ClusterHead); 843 if (!Cluster) { 844 // If we're invalidating a region with a symbolic offset, we need to make 845 // sure we don't treat the base region as uninitialized anymore. 846 if (TopKey.hasSymbolicOffset()) { 847 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 848 return B.addBinding(Concrete, BindingKey::Default, UnknownVal()); 849 } 850 return B; 851 } 852 853 SmallVector<BindingPair, 32> Bindings; 854 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey, 855 /*IncludeAllDefaultBindings=*/false); 856 857 ClusterBindingsRef Result(*Cluster, CBFactory); 858 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 859 E = Bindings.end(); 860 I != E; ++I) 861 Result = Result.remove(I->first); 862 863 // If we're invalidating a region with a symbolic offset, we need to make sure 864 // we don't treat the base region as uninitialized anymore. 865 // FIXME: This isn't very precise; see the example in 866 // collectSubRegionBindings. 867 if (TopKey.hasSymbolicOffset()) { 868 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 869 Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default), 870 UnknownVal()); 871 } 872 873 if (Result.isEmpty()) 874 return B.remove(ClusterHead); 875 return B.add(ClusterHead, Result.asImmutableMap()); 876} 877 878namespace { 879class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker> 880{ 881 const Expr *Ex; 882 unsigned Count; 883 const LocationContext *LCtx; 884 InvalidatedSymbols &IS; 885 StoreManager::InvalidatedRegions *Regions; 886public: 887 invalidateRegionsWorker(RegionStoreManager &rm, 888 ProgramStateManager &stateMgr, 889 RegionBindingsRef b, 890 const Expr *ex, unsigned count, 891 const LocationContext *lctx, 892 InvalidatedSymbols &is, 893 StoreManager::InvalidatedRegions *r, 894 bool includeGlobals) 895 : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, includeGlobals), 896 Ex(ex), Count(count), LCtx(lctx), IS(is), Regions(r) {} 897 898 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C, 899 bool Flag); 900 void VisitBinding(SVal V); 901}; 902} 903 904void invalidateRegionsWorker::VisitBinding(SVal V) { 905 // A symbol? Mark it touched by the invalidation. 906 if (SymbolRef Sym = V.getAsSymbol()) 907 IS.insert(Sym); 908 909 if (const MemRegion *R = V.getAsRegion()) { 910 AddToWorkList(R); 911 return; 912 } 913 914 // Is it a LazyCompoundVal? All references get invalidated as well. 915 if (Optional<nonloc::LazyCompoundVal> LCS = 916 V.getAs<nonloc::LazyCompoundVal>()) { 917 918 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 919 920 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 921 E = Vals.end(); 922 I != E; ++I) 923 VisitBinding(*I); 924 925 return; 926 } 927} 928 929void invalidateRegionsWorker::VisitCluster(const MemRegion *baseR, 930 const ClusterBindings *C, 931 bool IsConst) { 932 if (C) { 933 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) 934 VisitBinding(I.getData()); 935 936 if (!IsConst) 937 B = B.remove(baseR); 938 } 939 940 // BlockDataRegion? If so, invalidate captured variables that are passed 941 // by reference. 942 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) { 943 for (BlockDataRegion::referenced_vars_iterator 944 BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ; 945 BI != BE; ++BI) { 946 const VarRegion *VR = BI.getCapturedRegion(); 947 const VarDecl *VD = VR->getDecl(); 948 if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage()) { 949 AddToWorkList(VR); 950 } 951 else if (Loc::isLocType(VR->getValueType())) { 952 // Map the current bindings to a Store to retrieve the value 953 // of the binding. If that binding itself is a region, we should 954 // invalidate that region. This is because a block may capture 955 // a pointer value, but the thing pointed by that pointer may 956 // get invalidated. 957 SVal V = RM.getBinding(B, loc::MemRegionVal(VR)); 958 if (Optional<Loc> L = V.getAs<Loc>()) { 959 if (const MemRegion *LR = L->getAsRegion()) 960 AddToWorkList(LR); 961 } 962 } 963 } 964 return; 965 } 966 967 if (IsConst) 968 return; 969 970 // Symbolic region? Mark that symbol touched by the invalidation. 971 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) 972 IS.insert(SR->getSymbol()); 973 974 // Otherwise, we have a normal data region. Record that we touched the region. 975 if (Regions) 976 Regions->push_back(baseR); 977 978 if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) { 979 // Invalidate the region by setting its default value to 980 // conjured symbol. The type of the symbol is irrelavant. 981 DefinedOrUnknownSVal V = 982 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count); 983 B = B.addBinding(baseR, BindingKey::Default, V); 984 return; 985 } 986 987 if (!baseR->isBoundable()) 988 return; 989 990 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR); 991 QualType T = TR->getValueType(); 992 993 // Invalidate the binding. 994 if (T->isStructureOrClassType()) { 995 // Invalidate the region by setting its default value to 996 // conjured symbol. The type of the symbol is irrelavant. 997 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 998 Ctx.IntTy, Count); 999 B = B.addBinding(baseR, BindingKey::Default, V); 1000 return; 1001 } 1002 1003 if (const ArrayType *AT = Ctx.getAsArrayType(T)) { 1004 // Set the default value of the array to conjured symbol. 1005 DefinedOrUnknownSVal V = 1006 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1007 AT->getElementType(), Count); 1008 B = B.addBinding(baseR, BindingKey::Default, V); 1009 return; 1010 } 1011 1012 if (includeGlobals && 1013 isa<NonStaticGlobalSpaceRegion>(baseR->getMemorySpace())) { 1014 // If the region is a global and we are invalidating all globals, 1015 // just erase the entry. This causes all globals to be lazily 1016 // symbolicated from the same base symbol. 1017 B = B.removeBinding(baseR); 1018 return; 1019 } 1020 1021 1022 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1023 T,Count); 1024 assert(SymbolManager::canSymbolicate(T) || V.isUnknown()); 1025 B = B.addBinding(baseR, BindingKey::Direct, V); 1026} 1027 1028RegionBindingsRef 1029RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K, 1030 const Expr *Ex, 1031 unsigned Count, 1032 const LocationContext *LCtx, 1033 RegionBindingsRef B, 1034 InvalidatedRegions *Invalidated) { 1035 // Bind the globals memory space to a new symbol that we will use to derive 1036 // the bindings for all globals. 1037 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K); 1038 SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx, 1039 /* type does not matter */ Ctx.IntTy, 1040 Count); 1041 1042 B = B.removeBinding(GS) 1043 .addBinding(BindingKey::Make(GS, BindingKey::Default), V); 1044 1045 // Even if there are no bindings in the global scope, we still need to 1046 // record that we touched it. 1047 if (Invalidated) 1048 Invalidated->push_back(GS); 1049 1050 return B; 1051} 1052 1053StoreRef 1054RegionStoreManager::invalidateRegions(Store store, 1055 ArrayRef<const MemRegion *> Regions, 1056 const Expr *Ex, unsigned Count, 1057 const LocationContext *LCtx, 1058 InvalidatedSymbols &IS, 1059 const CallEvent *Call, 1060 ArrayRef<const MemRegion *> ConstRegions, 1061 InvalidatedRegions *Invalidated) { 1062 RegionBindingsRef B = RegionStoreManager::getRegionBindings(store); 1063 invalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, 1064 Invalidated, false); 1065 1066 // Scan the bindings and generate the clusters. 1067 W.GenerateClusters(); 1068 1069 // Add the regions to the worklist. 1070 for (ArrayRef<const MemRegion *>::iterator 1071 I = Regions.begin(), E = Regions.end(); I != E; ++I) 1072 W.AddToWorkList(*I, /*IsConst=*/false); 1073 1074 for (ArrayRef<const MemRegion *>::iterator I = ConstRegions.begin(), 1075 E = ConstRegions.end(); 1076 I != E; ++I) { 1077 W.AddToWorkList(*I, /*IsConst=*/true); 1078 } 1079 1080 W.RunWorkList(); 1081 1082 // Return the new bindings. 1083 B = W.getRegionBindings(); 1084 1085 // For calls, determine which global regions should be invalidated and 1086 // invalidate them. (Note that function-static and immutable globals are never 1087 // invalidated by this.) 1088 // TODO: This could possibly be more precise with modules. 1089 if (Call) { 1090 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1091 Ex, Count, LCtx, B, Invalidated); 1092 1093 if (!Call->isInSystemHeader()) { 1094 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind, 1095 Ex, Count, LCtx, B, Invalidated); 1096 } 1097 } 1098 1099 return StoreRef(B.asStore(), *this); 1100} 1101 1102//===----------------------------------------------------------------------===// 1103// Extents for regions. 1104//===----------------------------------------------------------------------===// 1105 1106DefinedOrUnknownSVal 1107RegionStoreManager::getSizeInElements(ProgramStateRef state, 1108 const MemRegion *R, 1109 QualType EleTy) { 1110 SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder); 1111 const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size); 1112 if (!SizeInt) 1113 return UnknownVal(); 1114 1115 CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue()); 1116 1117 if (Ctx.getAsVariableArrayType(EleTy)) { 1118 // FIXME: We need to track extra state to properly record the size 1119 // of VLAs. Returning UnknownVal here, however, is a stop-gap so that 1120 // we don't have a divide-by-zero below. 1121 return UnknownVal(); 1122 } 1123 1124 CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy); 1125 1126 // If a variable is reinterpreted as a type that doesn't fit into a larger 1127 // type evenly, round it down. 1128 // This is a signed value, since it's used in arithmetic with signed indices. 1129 return svalBuilder.makeIntVal(RegionSize / EleSize, false); 1130} 1131 1132//===----------------------------------------------------------------------===// 1133// Location and region casting. 1134//===----------------------------------------------------------------------===// 1135 1136/// ArrayToPointer - Emulates the "decay" of an array to a pointer 1137/// type. 'Array' represents the lvalue of the array being decayed 1138/// to a pointer, and the returned SVal represents the decayed 1139/// version of that lvalue (i.e., a pointer to the first element of 1140/// the array). This is called by ExprEngine when evaluating casts 1141/// from arrays to pointers. 1142SVal RegionStoreManager::ArrayToPointer(Loc Array) { 1143 if (!Array.getAs<loc::MemRegionVal>()) 1144 return UnknownVal(); 1145 1146 const MemRegion* R = Array.castAs<loc::MemRegionVal>().getRegion(); 1147 const TypedValueRegion* ArrayR = dyn_cast<TypedValueRegion>(R); 1148 1149 if (!ArrayR) 1150 return UnknownVal(); 1151 1152 // Strip off typedefs from the ArrayRegion's ValueType. 1153 QualType T = ArrayR->getValueType().getDesugaredType(Ctx); 1154 const ArrayType *AT = cast<ArrayType>(T); 1155 T = AT->getElementType(); 1156 1157 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex(); 1158 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, ArrayR, Ctx)); 1159} 1160 1161//===----------------------------------------------------------------------===// 1162// Loading values from regions. 1163//===----------------------------------------------------------------------===// 1164 1165SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) { 1166 assert(!L.getAs<UnknownVal>() && "location unknown"); 1167 assert(!L.getAs<UndefinedVal>() && "location undefined"); 1168 1169 // For access to concrete addresses, return UnknownVal. Checks 1170 // for null dereferences (and similar errors) are done by checkers, not 1171 // the Store. 1172 // FIXME: We can consider lazily symbolicating such memory, but we really 1173 // should defer this when we can reason easily about symbolicating arrays 1174 // of bytes. 1175 if (L.getAs<loc::ConcreteInt>()) { 1176 return UnknownVal(); 1177 } 1178 if (!L.getAs<loc::MemRegionVal>()) { 1179 return UnknownVal(); 1180 } 1181 1182 const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion(); 1183 1184 if (isa<AllocaRegion>(MR) || 1185 isa<SymbolicRegion>(MR) || 1186 isa<CodeTextRegion>(MR)) { 1187 if (T.isNull()) { 1188 if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR)) 1189 T = TR->getLocationType(); 1190 else { 1191 const SymbolicRegion *SR = cast<SymbolicRegion>(MR); 1192 T = SR->getSymbol()->getType(); 1193 } 1194 } 1195 MR = GetElementZeroRegion(MR, T); 1196 } 1197 1198 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument 1199 // instead of 'Loc', and have the other Loc cases handled at a higher level. 1200 const TypedValueRegion *R = cast<TypedValueRegion>(MR); 1201 QualType RTy = R->getValueType(); 1202 1203 // FIXME: we do not yet model the parts of a complex type, so treat the 1204 // whole thing as "unknown". 1205 if (RTy->isAnyComplexType()) 1206 return UnknownVal(); 1207 1208 // FIXME: We should eventually handle funny addressing. e.g.: 1209 // 1210 // int x = ...; 1211 // int *p = &x; 1212 // char *q = (char*) p; 1213 // char c = *q; // returns the first byte of 'x'. 1214 // 1215 // Such funny addressing will occur due to layering of regions. 1216 if (RTy->isStructureOrClassType()) 1217 return getBindingForStruct(B, R); 1218 1219 // FIXME: Handle unions. 1220 if (RTy->isUnionType()) 1221 return UnknownVal(); 1222 1223 if (RTy->isArrayType()) { 1224 if (RTy->isConstantArrayType()) 1225 return getBindingForArray(B, R); 1226 else 1227 return UnknownVal(); 1228 } 1229 1230 // FIXME: handle Vector types. 1231 if (RTy->isVectorType()) 1232 return UnknownVal(); 1233 1234 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R)) 1235 return CastRetrievedVal(getBindingForField(B, FR), FR, T, false); 1236 1237 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) { 1238 // FIXME: Here we actually perform an implicit conversion from the loaded 1239 // value to the element type. Eventually we want to compose these values 1240 // more intelligently. For example, an 'element' can encompass multiple 1241 // bound regions (e.g., several bound bytes), or could be a subset of 1242 // a larger value. 1243 return CastRetrievedVal(getBindingForElement(B, ER), ER, T, false); 1244 } 1245 1246 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) { 1247 // FIXME: Here we actually perform an implicit conversion from the loaded 1248 // value to the ivar type. What we should model is stores to ivars 1249 // that blow past the extent of the ivar. If the address of the ivar is 1250 // reinterpretted, it is possible we stored a different value that could 1251 // fit within the ivar. Either we need to cast these when storing them 1252 // or reinterpret them lazily (as we do here). 1253 return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T, false); 1254 } 1255 1256 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { 1257 // FIXME: Here we actually perform an implicit conversion from the loaded 1258 // value to the variable type. What we should model is stores to variables 1259 // that blow past the extent of the variable. If the address of the 1260 // variable is reinterpretted, it is possible we stored a different value 1261 // that could fit within the variable. Either we need to cast these when 1262 // storing them or reinterpret them lazily (as we do here). 1263 return CastRetrievedVal(getBindingForVar(B, VR), VR, T, false); 1264 } 1265 1266 const SVal *V = B.lookup(R, BindingKey::Direct); 1267 1268 // Check if the region has a binding. 1269 if (V) 1270 return *V; 1271 1272 // The location does not have a bound value. This means that it has 1273 // the value it had upon its creation and/or entry to the analyzed 1274 // function/method. These are either symbolic values or 'undefined'. 1275 if (R->hasStackNonParametersStorage()) { 1276 // All stack variables are considered to have undefined values 1277 // upon creation. All heap allocated blocks are considered to 1278 // have undefined values as well unless they are explicitly bound 1279 // to specific values. 1280 return UndefinedVal(); 1281 } 1282 1283 // All other values are symbolic. 1284 return svalBuilder.getRegionValueSymbolVal(R); 1285} 1286 1287static QualType getUnderlyingType(const SubRegion *R) { 1288 QualType RegionTy; 1289 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) 1290 RegionTy = TVR->getValueType(); 1291 1292 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 1293 RegionTy = SR->getSymbol()->getType(); 1294 1295 return RegionTy; 1296} 1297 1298/// Checks to see if store \p B has a lazy binding for region \p R. 1299/// 1300/// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected 1301/// if there are additional bindings within \p R. 1302/// 1303/// Note that unlike RegionStoreManager::findLazyBinding, this will not search 1304/// for lazy bindings for super-regions of \p R. 1305static Optional<nonloc::LazyCompoundVal> 1306getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B, 1307 const SubRegion *R, bool AllowSubregionBindings) { 1308 Optional<SVal> V = B.getDefaultBinding(R); 1309 if (!V) 1310 return None; 1311 1312 Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>(); 1313 if (!LCV) 1314 return None; 1315 1316 // If the LCV is for a subregion, the types might not match, and we shouldn't 1317 // reuse the binding. 1318 QualType RegionTy = getUnderlyingType(R); 1319 if (!RegionTy.isNull() && 1320 !RegionTy->isVoidPointerType()) { 1321 QualType SourceRegionTy = LCV->getRegion()->getValueType(); 1322 if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy)) 1323 return None; 1324 } 1325 1326 if (!AllowSubregionBindings) { 1327 // If there are any other bindings within this region, we shouldn't reuse 1328 // the top-level binding. 1329 SmallVector<BindingPair, 16> Bindings; 1330 collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R, 1331 /*IncludeAllDefaultBindings=*/true); 1332 if (Bindings.size() > 1) 1333 return None; 1334 } 1335 1336 return *LCV; 1337} 1338 1339 1340std::pair<Store, const SubRegion *> 1341RegionStoreManager::findLazyBinding(RegionBindingsConstRef B, 1342 const SubRegion *R, 1343 const SubRegion *originalRegion) { 1344 if (originalRegion != R) { 1345 if (Optional<nonloc::LazyCompoundVal> V = 1346 getExistingLazyBinding(svalBuilder, B, R, true)) 1347 return std::make_pair(V->getStore(), V->getRegion()); 1348 } 1349 1350 typedef std::pair<Store, const SubRegion *> StoreRegionPair; 1351 StoreRegionPair Result = StoreRegionPair(); 1352 1353 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 1354 Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()), 1355 originalRegion); 1356 1357 if (Result.second) 1358 Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second); 1359 1360 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) { 1361 Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()), 1362 originalRegion); 1363 1364 if (Result.second) 1365 Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second); 1366 1367 } else if (const CXXBaseObjectRegion *BaseReg = 1368 dyn_cast<CXXBaseObjectRegion>(R)) { 1369 // C++ base object region is another kind of region that we should blast 1370 // through to look for lazy compound value. It is like a field region. 1371 Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()), 1372 originalRegion); 1373 1374 if (Result.second) 1375 Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg, 1376 Result.second); 1377 } 1378 1379 return Result; 1380} 1381 1382SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B, 1383 const ElementRegion* R) { 1384 // We do not currently model bindings of the CompoundLiteralregion. 1385 if (isa<CompoundLiteralRegion>(R->getBaseRegion())) 1386 return UnknownVal(); 1387 1388 // Check if the region has a binding. 1389 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1390 return *V; 1391 1392 const MemRegion* superR = R->getSuperRegion(); 1393 1394 // Check if the region is an element region of a string literal. 1395 if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) { 1396 // FIXME: Handle loads from strings where the literal is treated as 1397 // an integer, e.g., *((unsigned int*)"hello") 1398 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType(); 1399 if (T != Ctx.getCanonicalType(R->getElementType())) 1400 return UnknownVal(); 1401 1402 const StringLiteral *Str = StrR->getStringLiteral(); 1403 SVal Idx = R->getIndex(); 1404 if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) { 1405 int64_t i = CI->getValue().getSExtValue(); 1406 // Abort on string underrun. This can be possible by arbitrary 1407 // clients of getBindingForElement(). 1408 if (i < 0) 1409 return UndefinedVal(); 1410 int64_t length = Str->getLength(); 1411 // Technically, only i == length is guaranteed to be null. 1412 // However, such overflows should be caught before reaching this point; 1413 // the only time such an access would be made is if a string literal was 1414 // used to initialize a larger array. 1415 char c = (i >= length) ? '\0' : Str->getCodeUnit(i); 1416 return svalBuilder.makeIntVal(c, T); 1417 } 1418 } 1419 1420 // Check for loads from a code text region. For such loads, just give up. 1421 if (isa<CodeTextRegion>(superR)) 1422 return UnknownVal(); 1423 1424 // Handle the case where we are indexing into a larger scalar object. 1425 // For example, this handles: 1426 // int x = ... 1427 // char *y = &x; 1428 // return *y; 1429 // FIXME: This is a hack, and doesn't do anything really intelligent yet. 1430 const RegionRawOffset &O = R->getAsArrayOffset(); 1431 1432 // If we cannot reason about the offset, return an unknown value. 1433 if (!O.getRegion()) 1434 return UnknownVal(); 1435 1436 if (const TypedValueRegion *baseR = 1437 dyn_cast_or_null<TypedValueRegion>(O.getRegion())) { 1438 QualType baseT = baseR->getValueType(); 1439 if (baseT->isScalarType()) { 1440 QualType elemT = R->getElementType(); 1441 if (elemT->isScalarType()) { 1442 if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) { 1443 if (const Optional<SVal> &V = B.getDirectBinding(superR)) { 1444 if (SymbolRef parentSym = V->getAsSymbol()) 1445 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1446 1447 if (V->isUnknownOrUndef()) 1448 return *V; 1449 // Other cases: give up. We are indexing into a larger object 1450 // that has some value, but we don't know how to handle that yet. 1451 return UnknownVal(); 1452 } 1453 } 1454 } 1455 } 1456 } 1457 return getBindingForFieldOrElementCommon(B, R, R->getElementType(),superR); 1458} 1459 1460SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B, 1461 const FieldRegion* R) { 1462 1463 // Check if the region has a binding. 1464 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1465 return *V; 1466 1467 QualType Ty = R->getValueType(); 1468 return getBindingForFieldOrElementCommon(B, R, Ty, R->getSuperRegion()); 1469} 1470 1471Optional<SVal> 1472RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 1473 const MemRegion *superR, 1474 const TypedValueRegion *R, 1475 QualType Ty) { 1476 1477 if (const Optional<SVal> &D = B.getDefaultBinding(superR)) { 1478 const SVal &val = D.getValue(); 1479 if (SymbolRef parentSym = val.getAsSymbol()) 1480 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1481 1482 if (val.isZeroConstant()) 1483 return svalBuilder.makeZeroVal(Ty); 1484 1485 if (val.isUnknownOrUndef()) 1486 return val; 1487 1488 // Lazy bindings are usually handled through getExistingLazyBinding(). 1489 // We should unify these two code paths at some point. 1490 if (val.getAs<nonloc::LazyCompoundVal>()) 1491 return val; 1492 1493 llvm_unreachable("Unknown default value"); 1494 } 1495 1496 return None; 1497} 1498 1499SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion, 1500 RegionBindingsRef LazyBinding) { 1501 SVal Result; 1502 if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion)) 1503 Result = getBindingForElement(LazyBinding, ER); 1504 else 1505 Result = getBindingForField(LazyBinding, 1506 cast<FieldRegion>(LazyBindingRegion)); 1507 1508 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1509 // default value for /part/ of an aggregate from a default value for the 1510 // /entire/ aggregate. The most common case of this is when struct Outer 1511 // has as its first member a struct Inner, which is copied in from a stack 1512 // variable. In this case, even if the Outer's default value is symbolic, 0, 1513 // or unknown, it gets overridden by the Inner's default value of undefined. 1514 // 1515 // This is a general problem -- if the Inner is zero-initialized, the Outer 1516 // will now look zero-initialized. The proper way to solve this is with a 1517 // new version of RegionStore that tracks the extent of a binding as well 1518 // as the offset. 1519 // 1520 // This hack only takes care of the undefined case because that can very 1521 // quickly result in a warning. 1522 if (Result.isUndef()) 1523 Result = UnknownVal(); 1524 1525 return Result; 1526} 1527 1528SVal 1529RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 1530 const TypedValueRegion *R, 1531 QualType Ty, 1532 const MemRegion *superR) { 1533 1534 // At this point we have already checked in either getBindingForElement or 1535 // getBindingForField if 'R' has a direct binding. 1536 1537 // Lazy binding? 1538 Store lazyBindingStore = NULL; 1539 const SubRegion *lazyBindingRegion = NULL; 1540 llvm::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R); 1541 if (lazyBindingRegion) 1542 return getLazyBinding(lazyBindingRegion, 1543 getRegionBindings(lazyBindingStore)); 1544 1545 // Record whether or not we see a symbolic index. That can completely 1546 // be out of scope of our lookup. 1547 bool hasSymbolicIndex = false; 1548 1549 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1550 // default value for /part/ of an aggregate from a default value for the 1551 // /entire/ aggregate. The most common case of this is when struct Outer 1552 // has as its first member a struct Inner, which is copied in from a stack 1553 // variable. In this case, even if the Outer's default value is symbolic, 0, 1554 // or unknown, it gets overridden by the Inner's default value of undefined. 1555 // 1556 // This is a general problem -- if the Inner is zero-initialized, the Outer 1557 // will now look zero-initialized. The proper way to solve this is with a 1558 // new version of RegionStore that tracks the extent of a binding as well 1559 // as the offset. 1560 // 1561 // This hack only takes care of the undefined case because that can very 1562 // quickly result in a warning. 1563 bool hasPartialLazyBinding = false; 1564 1565 const SubRegion *Base = dyn_cast<SubRegion>(superR); 1566 while (Base) { 1567 if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) { 1568 if (D->getAs<nonloc::LazyCompoundVal>()) { 1569 hasPartialLazyBinding = true; 1570 break; 1571 } 1572 1573 return *D; 1574 } 1575 1576 if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) { 1577 NonLoc index = ER->getIndex(); 1578 if (!index.isConstant()) 1579 hasSymbolicIndex = true; 1580 } 1581 1582 // If our super region is a field or element itself, walk up the region 1583 // hierarchy to see if there is a default value installed in an ancestor. 1584 Base = dyn_cast<SubRegion>(Base->getSuperRegion()); 1585 } 1586 1587 if (R->hasStackNonParametersStorage()) { 1588 if (isa<ElementRegion>(R)) { 1589 // Currently we don't reason specially about Clang-style vectors. Check 1590 // if superR is a vector and if so return Unknown. 1591 if (const TypedValueRegion *typedSuperR = 1592 dyn_cast<TypedValueRegion>(superR)) { 1593 if (typedSuperR->getValueType()->isVectorType()) 1594 return UnknownVal(); 1595 } 1596 } 1597 1598 // FIXME: We also need to take ElementRegions with symbolic indexes into 1599 // account. This case handles both directly accessing an ElementRegion 1600 // with a symbolic offset, but also fields within an element with 1601 // a symbolic offset. 1602 if (hasSymbolicIndex) 1603 return UnknownVal(); 1604 1605 if (!hasPartialLazyBinding) 1606 return UndefinedVal(); 1607 } 1608 1609 // All other values are symbolic. 1610 return svalBuilder.getRegionValueSymbolVal(R); 1611} 1612 1613SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B, 1614 const ObjCIvarRegion* R) { 1615 // Check if the region has a binding. 1616 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1617 return *V; 1618 1619 const MemRegion *superR = R->getSuperRegion(); 1620 1621 // Check if the super region has a default binding. 1622 if (const Optional<SVal> &V = B.getDefaultBinding(superR)) { 1623 if (SymbolRef parentSym = V->getAsSymbol()) 1624 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1625 1626 // Other cases: give up. 1627 return UnknownVal(); 1628 } 1629 1630 return getBindingForLazySymbol(R); 1631} 1632 1633static Optional<SVal> getConstValue(SValBuilder &SVB, const VarDecl *VD) { 1634 ASTContext &Ctx = SVB.getContext(); 1635 if (!VD->getType().isConstQualified()) 1636 return None; 1637 1638 const Expr *Init = VD->getInit(); 1639 if (!Init) 1640 return None; 1641 1642 llvm::APSInt Result; 1643 if (!Init->isGLValue() && Init->EvaluateAsInt(Result, Ctx)) 1644 return SVB.makeIntVal(Result); 1645 1646 if (Init->isNullPointerConstant(Ctx, Expr::NPC_ValueDependentIsNotNull)) 1647 return SVB.makeNull(); 1648 1649 // FIXME: Handle other possible constant expressions. 1650 return None; 1651} 1652 1653SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B, 1654 const VarRegion *R) { 1655 1656 // Check if the region has a binding. 1657 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1658 return *V; 1659 1660 // Lazily derive a value for the VarRegion. 1661 const VarDecl *VD = R->getDecl(); 1662 const MemSpaceRegion *MS = R->getMemorySpace(); 1663 1664 // Arguments are always symbolic. 1665 if (isa<StackArgumentsSpaceRegion>(MS)) 1666 return svalBuilder.getRegionValueSymbolVal(R); 1667 1668 // Is 'VD' declared constant? If so, retrieve the constant value. 1669 if (Optional<SVal> V = getConstValue(svalBuilder, VD)) 1670 return *V; 1671 1672 // This must come after the check for constants because closure-captured 1673 // constant variables may appear in UnknownSpaceRegion. 1674 if (isa<UnknownSpaceRegion>(MS)) 1675 return svalBuilder.getRegionValueSymbolVal(R); 1676 1677 if (isa<GlobalsSpaceRegion>(MS)) { 1678 QualType T = VD->getType(); 1679 1680 // Function-scoped static variables are default-initialized to 0; if they 1681 // have an initializer, it would have been processed by now. 1682 if (isa<StaticGlobalSpaceRegion>(MS)) 1683 return svalBuilder.makeZeroVal(T); 1684 1685 if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) { 1686 assert(!V->getAs<nonloc::LazyCompoundVal>()); 1687 return V.getValue(); 1688 } 1689 1690 return svalBuilder.getRegionValueSymbolVal(R); 1691 } 1692 1693 return UndefinedVal(); 1694} 1695 1696SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) { 1697 // All other values are symbolic. 1698 return svalBuilder.getRegionValueSymbolVal(R); 1699} 1700 1701const RegionStoreManager::SValListTy & 1702RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) { 1703 // First, check the cache. 1704 LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData()); 1705 if (I != LazyBindingsMap.end()) 1706 return I->second; 1707 1708 // If we don't have a list of values cached, start constructing it. 1709 SValListTy List; 1710 1711 const SubRegion *LazyR = LCV.getRegion(); 1712 RegionBindingsRef B = getRegionBindings(LCV.getStore()); 1713 1714 // If this region had /no/ bindings at the time, there are no interesting 1715 // values to return. 1716 const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion()); 1717 if (!Cluster) 1718 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1719 1720 SmallVector<BindingPair, 32> Bindings; 1721 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR, 1722 /*IncludeAllDefaultBindings=*/true); 1723 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 1724 E = Bindings.end(); 1725 I != E; ++I) { 1726 SVal V = I->second; 1727 if (V.isUnknownOrUndef() || V.isConstant()) 1728 continue; 1729 1730 if (Optional<nonloc::LazyCompoundVal> InnerLCV = 1731 V.getAs<nonloc::LazyCompoundVal>()) { 1732 const SValListTy &InnerList = getInterestingValues(*InnerLCV); 1733 List.insert(List.end(), InnerList.begin(), InnerList.end()); 1734 continue; 1735 } 1736 1737 List.push_back(V); 1738 } 1739 1740 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1741} 1742 1743NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B, 1744 const TypedValueRegion *R) { 1745 if (Optional<nonloc::LazyCompoundVal> V = 1746 getExistingLazyBinding(svalBuilder, B, R, false)) 1747 return *V; 1748 1749 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R); 1750} 1751 1752SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B, 1753 const TypedValueRegion *R) { 1754 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl(); 1755 if (RD->field_empty()) 1756 return UnknownVal(); 1757 1758 return createLazyBinding(B, R); 1759} 1760 1761SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B, 1762 const TypedValueRegion *R) { 1763 assert(Ctx.getAsConstantArrayType(R->getValueType()) && 1764 "Only constant array types can have compound bindings."); 1765 1766 return createLazyBinding(B, R); 1767} 1768 1769bool RegionStoreManager::includedInBindings(Store store, 1770 const MemRegion *region) const { 1771 RegionBindingsRef B = getRegionBindings(store); 1772 region = region->getBaseRegion(); 1773 1774 // Quick path: if the base is the head of a cluster, the region is live. 1775 if (B.lookup(region)) 1776 return true; 1777 1778 // Slow path: if the region is the VALUE of any binding, it is live. 1779 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) { 1780 const ClusterBindings &Cluster = RI.getData(); 1781 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1782 CI != CE; ++CI) { 1783 const SVal &D = CI.getData(); 1784 if (const MemRegion *R = D.getAsRegion()) 1785 if (R->getBaseRegion() == region) 1786 return true; 1787 } 1788 } 1789 1790 return false; 1791} 1792 1793//===----------------------------------------------------------------------===// 1794// Binding values to regions. 1795//===----------------------------------------------------------------------===// 1796 1797StoreRef RegionStoreManager::killBinding(Store ST, Loc L) { 1798 if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>()) 1799 if (const MemRegion* R = LV->getRegion()) 1800 return StoreRef(getRegionBindings(ST).removeBinding(R) 1801 .asImmutableMap() 1802 .getRootWithoutRetain(), 1803 *this); 1804 1805 return StoreRef(ST, *this); 1806} 1807 1808RegionBindingsRef 1809RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) { 1810 if (L.getAs<loc::ConcreteInt>()) 1811 return B; 1812 1813 // If we get here, the location should be a region. 1814 const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion(); 1815 1816 // Check if the region is a struct region. 1817 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) { 1818 QualType Ty = TR->getValueType(); 1819 if (Ty->isArrayType()) 1820 return bindArray(B, TR, V); 1821 if (Ty->isStructureOrClassType()) 1822 return bindStruct(B, TR, V); 1823 if (Ty->isVectorType()) 1824 return bindVector(B, TR, V); 1825 } 1826 1827 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 1828 // Binding directly to a symbolic region should be treated as binding 1829 // to element 0. 1830 QualType T = SR->getSymbol()->getType(); 1831 if (T->isAnyPointerType() || T->isReferenceType()) 1832 T = T->getPointeeType(); 1833 1834 R = GetElementZeroRegion(SR, T); 1835 } 1836 1837 // Clear out bindings that may overlap with this binding. 1838 RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R)); 1839 return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V); 1840} 1841 1842// FIXME: this method should be merged into Bind(). 1843StoreRef RegionStoreManager::bindCompoundLiteral(Store ST, 1844 const CompoundLiteralExpr *CL, 1845 const LocationContext *LC, 1846 SVal V) { 1847 return Bind(ST, loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)), V); 1848} 1849 1850RegionBindingsRef 1851RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B, 1852 const MemRegion *R, 1853 QualType T) { 1854 SVal V; 1855 1856 if (Loc::isLocType(T)) 1857 V = svalBuilder.makeNull(); 1858 else if (T->isIntegerType()) 1859 V = svalBuilder.makeZeroVal(T); 1860 else if (T->isStructureOrClassType() || T->isArrayType()) { 1861 // Set the default value to a zero constant when it is a structure 1862 // or array. The type doesn't really matter. 1863 V = svalBuilder.makeZeroVal(Ctx.IntTy); 1864 } 1865 else { 1866 // We can't represent values of this type, but we still need to set a value 1867 // to record that the region has been initialized. 1868 // If this assertion ever fires, a new case should be added above -- we 1869 // should know how to default-initialize any value we can symbolicate. 1870 assert(!SymbolManager::canSymbolicate(T) && "This type is representable"); 1871 V = UnknownVal(); 1872 } 1873 1874 return B.addBinding(R, BindingKey::Default, V); 1875} 1876 1877RegionBindingsRef 1878RegionStoreManager::bindArray(RegionBindingsConstRef B, 1879 const TypedValueRegion* R, 1880 SVal Init) { 1881 1882 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType())); 1883 QualType ElementTy = AT->getElementType(); 1884 Optional<uint64_t> Size; 1885 1886 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT)) 1887 Size = CAT->getSize().getZExtValue(); 1888 1889 // Check if the init expr is a string literal. 1890 if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) { 1891 const StringRegion *S = cast<StringRegion>(MRV->getRegion()); 1892 1893 // Treat the string as a lazy compound value. 1894 StoreRef store(B.asStore(), *this); 1895 nonloc::LazyCompoundVal LCV = svalBuilder.makeLazyCompoundVal(store, S) 1896 .castAs<nonloc::LazyCompoundVal>(); 1897 return bindAggregate(B, R, LCV); 1898 } 1899 1900 // Handle lazy compound values. 1901 if (Init.getAs<nonloc::LazyCompoundVal>()) 1902 return bindAggregate(B, R, Init); 1903 1904 // Remaining case: explicit compound values. 1905 1906 if (Init.isUnknown()) 1907 return setImplicitDefaultValue(B, R, ElementTy); 1908 1909 const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>(); 1910 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1911 uint64_t i = 0; 1912 1913 RegionBindingsRef NewB(B); 1914 1915 for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) { 1916 // The init list might be shorter than the array length. 1917 if (VI == VE) 1918 break; 1919 1920 const NonLoc &Idx = svalBuilder.makeArrayIndex(i); 1921 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx); 1922 1923 if (ElementTy->isStructureOrClassType()) 1924 NewB = bindStruct(NewB, ER, *VI); 1925 else if (ElementTy->isArrayType()) 1926 NewB = bindArray(NewB, ER, *VI); 1927 else 1928 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1929 } 1930 1931 // If the init list is shorter than the array length, set the 1932 // array default value. 1933 if (Size.hasValue() && i < Size.getValue()) 1934 NewB = setImplicitDefaultValue(NewB, R, ElementTy); 1935 1936 return NewB; 1937} 1938 1939RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B, 1940 const TypedValueRegion* R, 1941 SVal V) { 1942 QualType T = R->getValueType(); 1943 assert(T->isVectorType()); 1944 const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs. 1945 1946 // Handle lazy compound values and symbolic values. 1947 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 1948 return bindAggregate(B, R, V); 1949 1950 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1951 // that we are binding symbolic struct value. Kill the field values, and if 1952 // the value is symbolic go and bind it as a "default" binding. 1953 if (!V.getAs<nonloc::CompoundVal>()) { 1954 return bindAggregate(B, R, UnknownVal()); 1955 } 1956 1957 QualType ElemType = VT->getElementType(); 1958 nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>(); 1959 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1960 unsigned index = 0, numElements = VT->getNumElements(); 1961 RegionBindingsRef NewB(B); 1962 1963 for ( ; index != numElements ; ++index) { 1964 if (VI == VE) 1965 break; 1966 1967 NonLoc Idx = svalBuilder.makeArrayIndex(index); 1968 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx); 1969 1970 if (ElemType->isArrayType()) 1971 NewB = bindArray(NewB, ER, *VI); 1972 else if (ElemType->isStructureOrClassType()) 1973 NewB = bindStruct(NewB, ER, *VI); 1974 else 1975 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1976 } 1977 return NewB; 1978} 1979 1980RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B, 1981 const TypedValueRegion* R, 1982 SVal V) { 1983 if (!Features.supportsFields()) 1984 return B; 1985 1986 QualType T = R->getValueType(); 1987 assert(T->isStructureOrClassType()); 1988 1989 const RecordType* RT = T->getAs<RecordType>(); 1990 RecordDecl *RD = RT->getDecl(); 1991 1992 if (!RD->isCompleteDefinition()) 1993 return B; 1994 1995 // Handle lazy compound values and symbolic values. 1996 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 1997 return bindAggregate(B, R, V); 1998 1999 // We may get non-CompoundVal accidentally due to imprecise cast logic or 2000 // that we are binding symbolic struct value. Kill the field values, and if 2001 // the value is symbolic go and bind it as a "default" binding. 2002 if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>()) 2003 return bindAggregate(B, R, UnknownVal()); 2004 2005 const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>(); 2006 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2007 2008 RecordDecl::field_iterator FI, FE; 2009 RegionBindingsRef NewB(B); 2010 2011 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) { 2012 2013 if (VI == VE) 2014 break; 2015 2016 // Skip any unnamed bitfields to stay in sync with the initializers. 2017 if (FI->isUnnamedBitfield()) 2018 continue; 2019 2020 QualType FTy = FI->getType(); 2021 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R); 2022 2023 if (FTy->isArrayType()) 2024 NewB = bindArray(NewB, FR, *VI); 2025 else if (FTy->isStructureOrClassType()) 2026 NewB = bindStruct(NewB, FR, *VI); 2027 else 2028 NewB = bind(NewB, svalBuilder.makeLoc(FR), *VI); 2029 ++VI; 2030 } 2031 2032 // There may be fewer values in the initialize list than the fields of struct. 2033 if (FI != FE) { 2034 NewB = NewB.addBinding(R, BindingKey::Default, 2035 svalBuilder.makeIntVal(0, false)); 2036 } 2037 2038 return NewB; 2039} 2040 2041RegionBindingsRef 2042RegionStoreManager::bindAggregate(RegionBindingsConstRef B, 2043 const TypedRegion *R, 2044 SVal Val) { 2045 // Remove the old bindings, using 'R' as the root of all regions 2046 // we will invalidate. Then add the new binding. 2047 return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val); 2048} 2049 2050//===----------------------------------------------------------------------===// 2051// State pruning. 2052//===----------------------------------------------------------------------===// 2053 2054namespace { 2055class removeDeadBindingsWorker : 2056 public ClusterAnalysis<removeDeadBindingsWorker> { 2057 SmallVector<const SymbolicRegion*, 12> Postponed; 2058 SymbolReaper &SymReaper; 2059 const StackFrameContext *CurrentLCtx; 2060 2061public: 2062 removeDeadBindingsWorker(RegionStoreManager &rm, 2063 ProgramStateManager &stateMgr, 2064 RegionBindingsRef b, SymbolReaper &symReaper, 2065 const StackFrameContext *LCtx) 2066 : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b, 2067 /* includeGlobals = */ false), 2068 SymReaper(symReaper), CurrentLCtx(LCtx) {} 2069 2070 // Called by ClusterAnalysis. 2071 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C); 2072 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C); 2073 using ClusterAnalysis<removeDeadBindingsWorker>::VisitCluster; 2074 2075 bool UpdatePostponed(); 2076 void VisitBinding(SVal V); 2077}; 2078} 2079 2080void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR, 2081 const ClusterBindings &C) { 2082 2083 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) { 2084 if (SymReaper.isLive(VR)) 2085 AddToWorkList(baseR, &C); 2086 2087 return; 2088 } 2089 2090 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 2091 if (SymReaper.isLive(SR->getSymbol())) 2092 AddToWorkList(SR, &C); 2093 else 2094 Postponed.push_back(SR); 2095 2096 return; 2097 } 2098 2099 if (isa<NonStaticGlobalSpaceRegion>(baseR)) { 2100 AddToWorkList(baseR, &C); 2101 return; 2102 } 2103 2104 // CXXThisRegion in the current or parent location context is live. 2105 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) { 2106 const StackArgumentsSpaceRegion *StackReg = 2107 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion()); 2108 const StackFrameContext *RegCtx = StackReg->getStackFrame(); 2109 if (CurrentLCtx && 2110 (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))) 2111 AddToWorkList(TR, &C); 2112 } 2113} 2114 2115void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR, 2116 const ClusterBindings *C) { 2117 if (!C) 2118 return; 2119 2120 // Mark the symbol for any SymbolicRegion with live bindings as live itself. 2121 // This means we should continue to track that symbol. 2122 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR)) 2123 SymReaper.markLive(SymR->getSymbol()); 2124 2125 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) 2126 VisitBinding(I.getData()); 2127} 2128 2129void removeDeadBindingsWorker::VisitBinding(SVal V) { 2130 // Is it a LazyCompoundVal? All referenced regions are live as well. 2131 if (Optional<nonloc::LazyCompoundVal> LCS = 2132 V.getAs<nonloc::LazyCompoundVal>()) { 2133 2134 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 2135 2136 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 2137 E = Vals.end(); 2138 I != E; ++I) 2139 VisitBinding(*I); 2140 2141 return; 2142 } 2143 2144 // If V is a region, then add it to the worklist. 2145 if (const MemRegion *R = V.getAsRegion()) { 2146 AddToWorkList(R); 2147 2148 // All regions captured by a block are also live. 2149 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) { 2150 BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(), 2151 E = BR->referenced_vars_end(); 2152 for ( ; I != E; ++I) 2153 AddToWorkList(I.getCapturedRegion()); 2154 } 2155 } 2156 2157 2158 // Update the set of live symbols. 2159 for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end(); 2160 SI!=SE; ++SI) 2161 SymReaper.markLive(*SI); 2162} 2163 2164bool removeDeadBindingsWorker::UpdatePostponed() { 2165 // See if any postponed SymbolicRegions are actually live now, after 2166 // having done a scan. 2167 bool changed = false; 2168 2169 for (SmallVectorImpl<const SymbolicRegion*>::iterator 2170 I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) { 2171 if (const SymbolicRegion *SR = *I) { 2172 if (SymReaper.isLive(SR->getSymbol())) { 2173 changed |= AddToWorkList(SR); 2174 *I = NULL; 2175 } 2176 } 2177 } 2178 2179 return changed; 2180} 2181 2182StoreRef RegionStoreManager::removeDeadBindings(Store store, 2183 const StackFrameContext *LCtx, 2184 SymbolReaper& SymReaper) { 2185 RegionBindingsRef B = getRegionBindings(store); 2186 removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx); 2187 W.GenerateClusters(); 2188 2189 // Enqueue the region roots onto the worklist. 2190 for (SymbolReaper::region_iterator I = SymReaper.region_begin(), 2191 E = SymReaper.region_end(); I != E; ++I) { 2192 W.AddToWorkList(*I); 2193 } 2194 2195 do W.RunWorkList(); while (W.UpdatePostponed()); 2196 2197 // We have now scanned the store, marking reachable regions and symbols 2198 // as live. We now remove all the regions that are dead from the store 2199 // as well as update DSymbols with the set symbols that are now dead. 2200 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 2201 const MemRegion *Base = I.getKey(); 2202 2203 // If the cluster has been visited, we know the region has been marked. 2204 if (W.isVisited(Base)) 2205 continue; 2206 2207 // Remove the dead entry. 2208 B = B.remove(Base); 2209 2210 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base)) 2211 SymReaper.maybeDead(SymR->getSymbol()); 2212 2213 // Mark all non-live symbols that this binding references as dead. 2214 const ClusterBindings &Cluster = I.getData(); 2215 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 2216 CI != CE; ++CI) { 2217 SVal X = CI.getData(); 2218 SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end(); 2219 for (; SI != SE; ++SI) 2220 SymReaper.maybeDead(*SI); 2221 } 2222 } 2223 2224 return StoreRef(B.asStore(), *this); 2225} 2226 2227//===----------------------------------------------------------------------===// 2228// Utility methods. 2229//===----------------------------------------------------------------------===// 2230 2231void RegionStoreManager::print(Store store, raw_ostream &OS, 2232 const char* nl, const char *sep) { 2233 RegionBindingsRef B = getRegionBindings(store); 2234 OS << "Store (direct and default bindings), " 2235 << B.asStore() 2236 << " :" << nl; 2237 B.dump(OS, nl); 2238} 2239