RegionStore.cpp revision 683d25656f28937f78c815f70545139c432f1ff3
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 if (Top == ClusterHead) { 837 // We can remove an entire cluster's bindings all in one go. 838 return B.remove(Top); 839 } 840 841 const ClusterBindings *Cluster = B.lookup(ClusterHead); 842 if (!Cluster) 843 return B; 844 845 SmallVector<BindingPair, 32> Bindings; 846 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey, 847 /*IncludeAllDefaultBindings=*/false); 848 849 ClusterBindingsRef Result(*Cluster, CBFactory); 850 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 851 E = Bindings.end(); 852 I != E; ++I) 853 Result = Result.remove(I->first); 854 855 // If we're invalidating a region with a symbolic offset, we need to make sure 856 // we don't treat the base region as uninitialized anymore. 857 // FIXME: This isn't very precise; see the example in 858 // collectSubRegionBindings. 859 if (TopKey.hasSymbolicOffset()) { 860 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 861 Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default), 862 UnknownVal()); 863 } 864 865 if (Result.isEmpty()) 866 return B.remove(ClusterHead); 867 return B.add(ClusterHead, Result.asImmutableMap()); 868} 869 870namespace { 871class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker> 872{ 873 const Expr *Ex; 874 unsigned Count; 875 const LocationContext *LCtx; 876 InvalidatedSymbols &IS; 877 StoreManager::InvalidatedRegions *Regions; 878public: 879 invalidateRegionsWorker(RegionStoreManager &rm, 880 ProgramStateManager &stateMgr, 881 RegionBindingsRef b, 882 const Expr *ex, unsigned count, 883 const LocationContext *lctx, 884 InvalidatedSymbols &is, 885 StoreManager::InvalidatedRegions *r, 886 bool includeGlobals) 887 : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, includeGlobals), 888 Ex(ex), Count(count), LCtx(lctx), IS(is), Regions(r) {} 889 890 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C, 891 bool Flag); 892 void VisitBinding(SVal V); 893}; 894} 895 896void invalidateRegionsWorker::VisitBinding(SVal V) { 897 // A symbol? Mark it touched by the invalidation. 898 if (SymbolRef Sym = V.getAsSymbol()) 899 IS.insert(Sym); 900 901 if (const MemRegion *R = V.getAsRegion()) { 902 AddToWorkList(R); 903 return; 904 } 905 906 // Is it a LazyCompoundVal? All references get invalidated as well. 907 if (Optional<nonloc::LazyCompoundVal> LCS = 908 V.getAs<nonloc::LazyCompoundVal>()) { 909 910 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 911 912 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 913 E = Vals.end(); 914 I != E; ++I) 915 VisitBinding(*I); 916 917 return; 918 } 919} 920 921void invalidateRegionsWorker::VisitCluster(const MemRegion *baseR, 922 const ClusterBindings *C, 923 bool IsConst) { 924 if (C) { 925 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) 926 VisitBinding(I.getData()); 927 928 if (!IsConst) 929 B = B.remove(baseR); 930 } 931 932 // BlockDataRegion? If so, invalidate captured variables that are passed 933 // by reference. 934 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) { 935 for (BlockDataRegion::referenced_vars_iterator 936 BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ; 937 BI != BE; ++BI) { 938 const VarRegion *VR = BI.getCapturedRegion(); 939 const VarDecl *VD = VR->getDecl(); 940 if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage()) { 941 AddToWorkList(VR); 942 } 943 else if (Loc::isLocType(VR->getValueType())) { 944 // Map the current bindings to a Store to retrieve the value 945 // of the binding. If that binding itself is a region, we should 946 // invalidate that region. This is because a block may capture 947 // a pointer value, but the thing pointed by that pointer may 948 // get invalidated. 949 SVal V = RM.getBinding(B, loc::MemRegionVal(VR)); 950 if (Optional<Loc> L = V.getAs<Loc>()) { 951 if (const MemRegion *LR = L->getAsRegion()) 952 AddToWorkList(LR); 953 } 954 } 955 } 956 return; 957 } 958 959 if (IsConst) 960 return; 961 962 // Symbolic region? Mark that symbol touched by the invalidation. 963 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) 964 IS.insert(SR->getSymbol()); 965 966 // Otherwise, we have a normal data region. Record that we touched the region. 967 if (Regions) 968 Regions->push_back(baseR); 969 970 if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) { 971 // Invalidate the region by setting its default value to 972 // conjured symbol. The type of the symbol is irrelavant. 973 DefinedOrUnknownSVal V = 974 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count); 975 B = B.addBinding(baseR, BindingKey::Default, V); 976 return; 977 } 978 979 if (!baseR->isBoundable()) 980 return; 981 982 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR); 983 QualType T = TR->getValueType(); 984 985 // Invalidate the binding. 986 if (T->isStructureOrClassType()) { 987 // Invalidate the region by setting its default value to 988 // conjured symbol. The type of the symbol is irrelavant. 989 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 990 Ctx.IntTy, Count); 991 B = B.addBinding(baseR, BindingKey::Default, V); 992 return; 993 } 994 995 if (const ArrayType *AT = Ctx.getAsArrayType(T)) { 996 // Set the default value of the array to conjured symbol. 997 DefinedOrUnknownSVal V = 998 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 999 AT->getElementType(), Count); 1000 B = B.addBinding(baseR, BindingKey::Default, V); 1001 return; 1002 } 1003 1004 if (includeGlobals && 1005 isa<NonStaticGlobalSpaceRegion>(baseR->getMemorySpace())) { 1006 // If the region is a global and we are invalidating all globals, 1007 // just erase the entry. This causes all globals to be lazily 1008 // symbolicated from the same base symbol. 1009 B = B.removeBinding(baseR); 1010 return; 1011 } 1012 1013 1014 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1015 T,Count); 1016 assert(SymbolManager::canSymbolicate(T) || V.isUnknown()); 1017 B = B.addBinding(baseR, BindingKey::Direct, V); 1018} 1019 1020RegionBindingsRef 1021RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K, 1022 const Expr *Ex, 1023 unsigned Count, 1024 const LocationContext *LCtx, 1025 RegionBindingsRef B, 1026 InvalidatedRegions *Invalidated) { 1027 // Bind the globals memory space to a new symbol that we will use to derive 1028 // the bindings for all globals. 1029 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K); 1030 SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx, 1031 /* type does not matter */ Ctx.IntTy, 1032 Count); 1033 1034 B = B.removeBinding(GS) 1035 .addBinding(BindingKey::Make(GS, BindingKey::Default), V); 1036 1037 // Even if there are no bindings in the global scope, we still need to 1038 // record that we touched it. 1039 if (Invalidated) 1040 Invalidated->push_back(GS); 1041 1042 return B; 1043} 1044 1045StoreRef 1046RegionStoreManager::invalidateRegions(Store store, 1047 ArrayRef<const MemRegion *> Regions, 1048 const Expr *Ex, unsigned Count, 1049 const LocationContext *LCtx, 1050 InvalidatedSymbols &IS, 1051 const CallEvent *Call, 1052 ArrayRef<const MemRegion *> ConstRegions, 1053 InvalidatedRegions *Invalidated) { 1054 RegionBindingsRef B = RegionStoreManager::getRegionBindings(store); 1055 invalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, 1056 Invalidated, false); 1057 1058 // Scan the bindings and generate the clusters. 1059 W.GenerateClusters(); 1060 1061 // Add the regions to the worklist. 1062 for (ArrayRef<const MemRegion *>::iterator 1063 I = Regions.begin(), E = Regions.end(); I != E; ++I) 1064 W.AddToWorkList(*I, /*IsConst=*/false); 1065 1066 for (ArrayRef<const MemRegion *>::iterator I = ConstRegions.begin(), 1067 E = ConstRegions.end(); 1068 I != E; ++I) { 1069 W.AddToWorkList(*I, /*IsConst=*/true); 1070 } 1071 1072 W.RunWorkList(); 1073 1074 // Return the new bindings. 1075 B = W.getRegionBindings(); 1076 1077 // For calls, determine which global regions should be invalidated and 1078 // invalidate them. (Note that function-static and immutable globals are never 1079 // invalidated by this.) 1080 // TODO: This could possibly be more precise with modules. 1081 if (Call) { 1082 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1083 Ex, Count, LCtx, B, Invalidated); 1084 1085 if (!Call->isInSystemHeader()) { 1086 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind, 1087 Ex, Count, LCtx, B, Invalidated); 1088 } 1089 } 1090 1091 return StoreRef(B.asStore(), *this); 1092} 1093 1094//===----------------------------------------------------------------------===// 1095// Extents for regions. 1096//===----------------------------------------------------------------------===// 1097 1098DefinedOrUnknownSVal 1099RegionStoreManager::getSizeInElements(ProgramStateRef state, 1100 const MemRegion *R, 1101 QualType EleTy) { 1102 SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder); 1103 const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size); 1104 if (!SizeInt) 1105 return UnknownVal(); 1106 1107 CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue()); 1108 1109 if (Ctx.getAsVariableArrayType(EleTy)) { 1110 // FIXME: We need to track extra state to properly record the size 1111 // of VLAs. Returning UnknownVal here, however, is a stop-gap so that 1112 // we don't have a divide-by-zero below. 1113 return UnknownVal(); 1114 } 1115 1116 CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy); 1117 1118 // If a variable is reinterpreted as a type that doesn't fit into a larger 1119 // type evenly, round it down. 1120 // This is a signed value, since it's used in arithmetic with signed indices. 1121 return svalBuilder.makeIntVal(RegionSize / EleSize, false); 1122} 1123 1124//===----------------------------------------------------------------------===// 1125// Location and region casting. 1126//===----------------------------------------------------------------------===// 1127 1128/// ArrayToPointer - Emulates the "decay" of an array to a pointer 1129/// type. 'Array' represents the lvalue of the array being decayed 1130/// to a pointer, and the returned SVal represents the decayed 1131/// version of that lvalue (i.e., a pointer to the first element of 1132/// the array). This is called by ExprEngine when evaluating casts 1133/// from arrays to pointers. 1134SVal RegionStoreManager::ArrayToPointer(Loc Array) { 1135 if (!Array.getAs<loc::MemRegionVal>()) 1136 return UnknownVal(); 1137 1138 const MemRegion* R = Array.castAs<loc::MemRegionVal>().getRegion(); 1139 const TypedValueRegion* ArrayR = dyn_cast<TypedValueRegion>(R); 1140 1141 if (!ArrayR) 1142 return UnknownVal(); 1143 1144 // Strip off typedefs from the ArrayRegion's ValueType. 1145 QualType T = ArrayR->getValueType().getDesugaredType(Ctx); 1146 const ArrayType *AT = cast<ArrayType>(T); 1147 T = AT->getElementType(); 1148 1149 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex(); 1150 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, ArrayR, Ctx)); 1151} 1152 1153//===----------------------------------------------------------------------===// 1154// Loading values from regions. 1155//===----------------------------------------------------------------------===// 1156 1157SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) { 1158 assert(!L.getAs<UnknownVal>() && "location unknown"); 1159 assert(!L.getAs<UndefinedVal>() && "location undefined"); 1160 1161 // For access to concrete addresses, return UnknownVal. Checks 1162 // for null dereferences (and similar errors) are done by checkers, not 1163 // the Store. 1164 // FIXME: We can consider lazily symbolicating such memory, but we really 1165 // should defer this when we can reason easily about symbolicating arrays 1166 // of bytes. 1167 if (L.getAs<loc::ConcreteInt>()) { 1168 return UnknownVal(); 1169 } 1170 if (!L.getAs<loc::MemRegionVal>()) { 1171 return UnknownVal(); 1172 } 1173 1174 const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion(); 1175 1176 if (isa<AllocaRegion>(MR) || 1177 isa<SymbolicRegion>(MR) || 1178 isa<CodeTextRegion>(MR)) { 1179 if (T.isNull()) { 1180 if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR)) 1181 T = TR->getLocationType(); 1182 else { 1183 const SymbolicRegion *SR = cast<SymbolicRegion>(MR); 1184 T = SR->getSymbol()->getType(); 1185 } 1186 } 1187 MR = GetElementZeroRegion(MR, T); 1188 } 1189 1190 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument 1191 // instead of 'Loc', and have the other Loc cases handled at a higher level. 1192 const TypedValueRegion *R = cast<TypedValueRegion>(MR); 1193 QualType RTy = R->getValueType(); 1194 1195 // FIXME: we do not yet model the parts of a complex type, so treat the 1196 // whole thing as "unknown". 1197 if (RTy->isAnyComplexType()) 1198 return UnknownVal(); 1199 1200 // FIXME: We should eventually handle funny addressing. e.g.: 1201 // 1202 // int x = ...; 1203 // int *p = &x; 1204 // char *q = (char*) p; 1205 // char c = *q; // returns the first byte of 'x'. 1206 // 1207 // Such funny addressing will occur due to layering of regions. 1208 if (RTy->isStructureOrClassType()) 1209 return getBindingForStruct(B, R); 1210 1211 // FIXME: Handle unions. 1212 if (RTy->isUnionType()) 1213 return UnknownVal(); 1214 1215 if (RTy->isArrayType()) { 1216 if (RTy->isConstantArrayType()) 1217 return getBindingForArray(B, R); 1218 else 1219 return UnknownVal(); 1220 } 1221 1222 // FIXME: handle Vector types. 1223 if (RTy->isVectorType()) 1224 return UnknownVal(); 1225 1226 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R)) 1227 return CastRetrievedVal(getBindingForField(B, FR), FR, T, false); 1228 1229 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) { 1230 // FIXME: Here we actually perform an implicit conversion from the loaded 1231 // value to the element type. Eventually we want to compose these values 1232 // more intelligently. For example, an 'element' can encompass multiple 1233 // bound regions (e.g., several bound bytes), or could be a subset of 1234 // a larger value. 1235 return CastRetrievedVal(getBindingForElement(B, ER), ER, T, false); 1236 } 1237 1238 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) { 1239 // FIXME: Here we actually perform an implicit conversion from the loaded 1240 // value to the ivar type. What we should model is stores to ivars 1241 // that blow past the extent of the ivar. If the address of the ivar is 1242 // reinterpretted, it is possible we stored a different value that could 1243 // fit within the ivar. Either we need to cast these when storing them 1244 // or reinterpret them lazily (as we do here). 1245 return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T, false); 1246 } 1247 1248 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { 1249 // FIXME: Here we actually perform an implicit conversion from the loaded 1250 // value to the variable type. What we should model is stores to variables 1251 // that blow past the extent of the variable. If the address of the 1252 // variable is reinterpretted, it is possible we stored a different value 1253 // that could fit within the variable. Either we need to cast these when 1254 // storing them or reinterpret them lazily (as we do here). 1255 return CastRetrievedVal(getBindingForVar(B, VR), VR, T, false); 1256 } 1257 1258 const SVal *V = B.lookup(R, BindingKey::Direct); 1259 1260 // Check if the region has a binding. 1261 if (V) 1262 return *V; 1263 1264 // The location does not have a bound value. This means that it has 1265 // the value it had upon its creation and/or entry to the analyzed 1266 // function/method. These are either symbolic values or 'undefined'. 1267 if (R->hasStackNonParametersStorage()) { 1268 // All stack variables are considered to have undefined values 1269 // upon creation. All heap allocated blocks are considered to 1270 // have undefined values as well unless they are explicitly bound 1271 // to specific values. 1272 return UndefinedVal(); 1273 } 1274 1275 // All other values are symbolic. 1276 return svalBuilder.getRegionValueSymbolVal(R); 1277} 1278 1279static QualType getUnderlyingType(const SubRegion *R) { 1280 QualType RegionTy; 1281 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) 1282 RegionTy = TVR->getValueType(); 1283 1284 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 1285 RegionTy = SR->getSymbol()->getType(); 1286 1287 return RegionTy; 1288} 1289 1290/// Checks to see if store \p B has a lazy binding for region \p R. 1291/// 1292/// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected 1293/// if there are additional bindings within \p R. 1294/// 1295/// Note that unlike RegionStoreManager::findLazyBinding, this will not search 1296/// for lazy bindings for super-regions of \p R. 1297static Optional<nonloc::LazyCompoundVal> 1298getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B, 1299 const SubRegion *R, bool AllowSubregionBindings) { 1300 Optional<SVal> V = B.getDefaultBinding(R); 1301 if (!V) 1302 return None; 1303 1304 Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>(); 1305 if (!LCV) 1306 return None; 1307 1308 // If the LCV is for a subregion, the types might not match, and we shouldn't 1309 // reuse the binding. 1310 QualType RegionTy = getUnderlyingType(R); 1311 if (!RegionTy.isNull() && 1312 !RegionTy->isVoidPointerType()) { 1313 QualType SourceRegionTy = LCV->getRegion()->getValueType(); 1314 if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy)) 1315 return None; 1316 } 1317 1318 if (!AllowSubregionBindings) { 1319 // If there are any other bindings within this region, we shouldn't reuse 1320 // the top-level binding. 1321 SmallVector<BindingPair, 16> Bindings; 1322 collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R, 1323 /*IncludeAllDefaultBindings=*/true); 1324 if (Bindings.size() > 1) 1325 return None; 1326 } 1327 1328 return *LCV; 1329} 1330 1331 1332std::pair<Store, const SubRegion *> 1333RegionStoreManager::findLazyBinding(RegionBindingsConstRef B, 1334 const SubRegion *R, 1335 const SubRegion *originalRegion) { 1336 if (originalRegion != R) { 1337 if (Optional<nonloc::LazyCompoundVal> V = 1338 getExistingLazyBinding(svalBuilder, B, R, true)) 1339 return std::make_pair(V->getStore(), V->getRegion()); 1340 } 1341 1342 typedef std::pair<Store, const SubRegion *> StoreRegionPair; 1343 StoreRegionPair Result = StoreRegionPair(); 1344 1345 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 1346 Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()), 1347 originalRegion); 1348 1349 if (Result.second) 1350 Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second); 1351 1352 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) { 1353 Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()), 1354 originalRegion); 1355 1356 if (Result.second) 1357 Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second); 1358 1359 } else if (const CXXBaseObjectRegion *BaseReg = 1360 dyn_cast<CXXBaseObjectRegion>(R)) { 1361 // C++ base object region is another kind of region that we should blast 1362 // through to look for lazy compound value. It is like a field region. 1363 Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()), 1364 originalRegion); 1365 1366 if (Result.second) 1367 Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg, 1368 Result.second); 1369 } 1370 1371 return Result; 1372} 1373 1374SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B, 1375 const ElementRegion* R) { 1376 // We do not currently model bindings of the CompoundLiteralregion. 1377 if (isa<CompoundLiteralRegion>(R->getBaseRegion())) 1378 return UnknownVal(); 1379 1380 // Check if the region has a binding. 1381 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1382 return *V; 1383 1384 const MemRegion* superR = R->getSuperRegion(); 1385 1386 // Check if the region is an element region of a string literal. 1387 if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) { 1388 // FIXME: Handle loads from strings where the literal is treated as 1389 // an integer, e.g., *((unsigned int*)"hello") 1390 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType(); 1391 if (T != Ctx.getCanonicalType(R->getElementType())) 1392 return UnknownVal(); 1393 1394 const StringLiteral *Str = StrR->getStringLiteral(); 1395 SVal Idx = R->getIndex(); 1396 if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) { 1397 int64_t i = CI->getValue().getSExtValue(); 1398 // Abort on string underrun. This can be possible by arbitrary 1399 // clients of getBindingForElement(). 1400 if (i < 0) 1401 return UndefinedVal(); 1402 int64_t length = Str->getLength(); 1403 // Technically, only i == length is guaranteed to be null. 1404 // However, such overflows should be caught before reaching this point; 1405 // the only time such an access would be made is if a string literal was 1406 // used to initialize a larger array. 1407 char c = (i >= length) ? '\0' : Str->getCodeUnit(i); 1408 return svalBuilder.makeIntVal(c, T); 1409 } 1410 } 1411 1412 // Check for loads from a code text region. For such loads, just give up. 1413 if (isa<CodeTextRegion>(superR)) 1414 return UnknownVal(); 1415 1416 // Handle the case where we are indexing into a larger scalar object. 1417 // For example, this handles: 1418 // int x = ... 1419 // char *y = &x; 1420 // return *y; 1421 // FIXME: This is a hack, and doesn't do anything really intelligent yet. 1422 const RegionRawOffset &O = R->getAsArrayOffset(); 1423 1424 // If we cannot reason about the offset, return an unknown value. 1425 if (!O.getRegion()) 1426 return UnknownVal(); 1427 1428 if (const TypedValueRegion *baseR = 1429 dyn_cast_or_null<TypedValueRegion>(O.getRegion())) { 1430 QualType baseT = baseR->getValueType(); 1431 if (baseT->isScalarType()) { 1432 QualType elemT = R->getElementType(); 1433 if (elemT->isScalarType()) { 1434 if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) { 1435 if (const Optional<SVal> &V = B.getDirectBinding(superR)) { 1436 if (SymbolRef parentSym = V->getAsSymbol()) 1437 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1438 1439 if (V->isUnknownOrUndef()) 1440 return *V; 1441 // Other cases: give up. We are indexing into a larger object 1442 // that has some value, but we don't know how to handle that yet. 1443 return UnknownVal(); 1444 } 1445 } 1446 } 1447 } 1448 } 1449 return getBindingForFieldOrElementCommon(B, R, R->getElementType(),superR); 1450} 1451 1452SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B, 1453 const FieldRegion* R) { 1454 1455 // Check if the region has a binding. 1456 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1457 return *V; 1458 1459 QualType Ty = R->getValueType(); 1460 return getBindingForFieldOrElementCommon(B, R, Ty, R->getSuperRegion()); 1461} 1462 1463Optional<SVal> 1464RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 1465 const MemRegion *superR, 1466 const TypedValueRegion *R, 1467 QualType Ty) { 1468 1469 if (const Optional<SVal> &D = B.getDefaultBinding(superR)) { 1470 const SVal &val = D.getValue(); 1471 if (SymbolRef parentSym = val.getAsSymbol()) 1472 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1473 1474 if (val.isZeroConstant()) 1475 return svalBuilder.makeZeroVal(Ty); 1476 1477 if (val.isUnknownOrUndef()) 1478 return val; 1479 1480 // Lazy bindings are usually handled through getExistingLazyBinding(). 1481 // We should unify these two code paths at some point. 1482 if (val.getAs<nonloc::LazyCompoundVal>()) 1483 return val; 1484 1485 llvm_unreachable("Unknown default value"); 1486 } 1487 1488 return None; 1489} 1490 1491SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion, 1492 RegionBindingsRef LazyBinding) { 1493 SVal Result; 1494 if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion)) 1495 Result = getBindingForElement(LazyBinding, ER); 1496 else 1497 Result = getBindingForField(LazyBinding, 1498 cast<FieldRegion>(LazyBindingRegion)); 1499 1500 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1501 // default value for /part/ of an aggregate from a default value for the 1502 // /entire/ aggregate. The most common case of this is when struct Outer 1503 // has as its first member a struct Inner, which is copied in from a stack 1504 // variable. In this case, even if the Outer's default value is symbolic, 0, 1505 // or unknown, it gets overridden by the Inner's default value of undefined. 1506 // 1507 // This is a general problem -- if the Inner is zero-initialized, the Outer 1508 // will now look zero-initialized. The proper way to solve this is with a 1509 // new version of RegionStore that tracks the extent of a binding as well 1510 // as the offset. 1511 // 1512 // This hack only takes care of the undefined case because that can very 1513 // quickly result in a warning. 1514 if (Result.isUndef()) 1515 Result = UnknownVal(); 1516 1517 return Result; 1518} 1519 1520SVal 1521RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 1522 const TypedValueRegion *R, 1523 QualType Ty, 1524 const MemRegion *superR) { 1525 1526 // At this point we have already checked in either getBindingForElement or 1527 // getBindingForField if 'R' has a direct binding. 1528 1529 // Lazy binding? 1530 Store lazyBindingStore = NULL; 1531 const SubRegion *lazyBindingRegion = NULL; 1532 llvm::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R); 1533 if (lazyBindingRegion) 1534 return getLazyBinding(lazyBindingRegion, 1535 getRegionBindings(lazyBindingStore)); 1536 1537 // Record whether or not we see a symbolic index. That can completely 1538 // be out of scope of our lookup. 1539 bool hasSymbolicIndex = false; 1540 1541 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1542 // default value for /part/ of an aggregate from a default value for the 1543 // /entire/ aggregate. The most common case of this is when struct Outer 1544 // has as its first member a struct Inner, which is copied in from a stack 1545 // variable. In this case, even if the Outer's default value is symbolic, 0, 1546 // or unknown, it gets overridden by the Inner's default value of undefined. 1547 // 1548 // This is a general problem -- if the Inner is zero-initialized, the Outer 1549 // will now look zero-initialized. The proper way to solve this is with a 1550 // new version of RegionStore that tracks the extent of a binding as well 1551 // as the offset. 1552 // 1553 // This hack only takes care of the undefined case because that can very 1554 // quickly result in a warning. 1555 bool hasPartialLazyBinding = false; 1556 1557 const SubRegion *Base = dyn_cast<SubRegion>(superR); 1558 while (Base) { 1559 if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) { 1560 if (D->getAs<nonloc::LazyCompoundVal>()) { 1561 hasPartialLazyBinding = true; 1562 break; 1563 } 1564 1565 return *D; 1566 } 1567 1568 if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) { 1569 NonLoc index = ER->getIndex(); 1570 if (!index.isConstant()) 1571 hasSymbolicIndex = true; 1572 } 1573 1574 // If our super region is a field or element itself, walk up the region 1575 // hierarchy to see if there is a default value installed in an ancestor. 1576 Base = dyn_cast<SubRegion>(Base->getSuperRegion()); 1577 } 1578 1579 if (R->hasStackNonParametersStorage()) { 1580 if (isa<ElementRegion>(R)) { 1581 // Currently we don't reason specially about Clang-style vectors. Check 1582 // if superR is a vector and if so return Unknown. 1583 if (const TypedValueRegion *typedSuperR = 1584 dyn_cast<TypedValueRegion>(superR)) { 1585 if (typedSuperR->getValueType()->isVectorType()) 1586 return UnknownVal(); 1587 } 1588 } 1589 1590 // FIXME: We also need to take ElementRegions with symbolic indexes into 1591 // account. This case handles both directly accessing an ElementRegion 1592 // with a symbolic offset, but also fields within an element with 1593 // a symbolic offset. 1594 if (hasSymbolicIndex) 1595 return UnknownVal(); 1596 1597 if (!hasPartialLazyBinding) 1598 return UndefinedVal(); 1599 } 1600 1601 // All other values are symbolic. 1602 return svalBuilder.getRegionValueSymbolVal(R); 1603} 1604 1605SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B, 1606 const ObjCIvarRegion* R) { 1607 // Check if the region has a binding. 1608 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1609 return *V; 1610 1611 const MemRegion *superR = R->getSuperRegion(); 1612 1613 // Check if the super region has a default binding. 1614 if (const Optional<SVal> &V = B.getDefaultBinding(superR)) { 1615 if (SymbolRef parentSym = V->getAsSymbol()) 1616 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1617 1618 // Other cases: give up. 1619 return UnknownVal(); 1620 } 1621 1622 return getBindingForLazySymbol(R); 1623} 1624 1625static Optional<SVal> getConstValue(SValBuilder &SVB, const VarDecl *VD) { 1626 ASTContext &Ctx = SVB.getContext(); 1627 if (!VD->getType().isConstQualified()) 1628 return None; 1629 1630 const Expr *Init = VD->getInit(); 1631 if (!Init) 1632 return None; 1633 1634 llvm::APSInt Result; 1635 if (!Init->isGLValue() && Init->EvaluateAsInt(Result, Ctx)) 1636 return SVB.makeIntVal(Result); 1637 1638 if (Init->isNullPointerConstant(Ctx, Expr::NPC_ValueDependentIsNotNull)) 1639 return SVB.makeNull(); 1640 1641 // FIXME: Handle other possible constant expressions. 1642 return None; 1643} 1644 1645SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B, 1646 const VarRegion *R) { 1647 1648 // Check if the region has a binding. 1649 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1650 return *V; 1651 1652 // Lazily derive a value for the VarRegion. 1653 const VarDecl *VD = R->getDecl(); 1654 const MemSpaceRegion *MS = R->getMemorySpace(); 1655 1656 // Arguments are always symbolic. 1657 if (isa<StackArgumentsSpaceRegion>(MS)) 1658 return svalBuilder.getRegionValueSymbolVal(R); 1659 1660 // Is 'VD' declared constant? If so, retrieve the constant value. 1661 if (Optional<SVal> V = getConstValue(svalBuilder, VD)) 1662 return *V; 1663 1664 // This must come after the check for constants because closure-captured 1665 // constant variables may appear in UnknownSpaceRegion. 1666 if (isa<UnknownSpaceRegion>(MS)) 1667 return svalBuilder.getRegionValueSymbolVal(R); 1668 1669 if (isa<GlobalsSpaceRegion>(MS)) { 1670 QualType T = VD->getType(); 1671 1672 // Function-scoped static variables are default-initialized to 0; if they 1673 // have an initializer, it would have been processed by now. 1674 if (isa<StaticGlobalSpaceRegion>(MS)) 1675 return svalBuilder.makeZeroVal(T); 1676 1677 if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) { 1678 assert(!V->getAs<nonloc::LazyCompoundVal>()); 1679 return V.getValue(); 1680 } 1681 1682 return svalBuilder.getRegionValueSymbolVal(R); 1683 } 1684 1685 return UndefinedVal(); 1686} 1687 1688SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) { 1689 // All other values are symbolic. 1690 return svalBuilder.getRegionValueSymbolVal(R); 1691} 1692 1693const RegionStoreManager::SValListTy & 1694RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) { 1695 // First, check the cache. 1696 LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData()); 1697 if (I != LazyBindingsMap.end()) 1698 return I->second; 1699 1700 // If we don't have a list of values cached, start constructing it. 1701 SValListTy List; 1702 1703 const SubRegion *LazyR = LCV.getRegion(); 1704 RegionBindingsRef B = getRegionBindings(LCV.getStore()); 1705 1706 // If this region had /no/ bindings at the time, there are no interesting 1707 // values to return. 1708 const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion()); 1709 if (!Cluster) 1710 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1711 1712 SmallVector<BindingPair, 32> Bindings; 1713 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR, 1714 /*IncludeAllDefaultBindings=*/true); 1715 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 1716 E = Bindings.end(); 1717 I != E; ++I) { 1718 SVal V = I->second; 1719 if (V.isUnknownOrUndef() || V.isConstant()) 1720 continue; 1721 1722 if (Optional<nonloc::LazyCompoundVal> InnerLCV = 1723 V.getAs<nonloc::LazyCompoundVal>()) { 1724 const SValListTy &InnerList = getInterestingValues(*InnerLCV); 1725 List.insert(List.end(), InnerList.begin(), InnerList.end()); 1726 continue; 1727 } 1728 1729 List.push_back(V); 1730 } 1731 1732 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1733} 1734 1735NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B, 1736 const TypedValueRegion *R) { 1737 if (Optional<nonloc::LazyCompoundVal> V = 1738 getExistingLazyBinding(svalBuilder, B, R, false)) 1739 return *V; 1740 1741 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R); 1742} 1743 1744SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B, 1745 const TypedValueRegion *R) { 1746 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl(); 1747 if (RD->field_empty()) 1748 return UnknownVal(); 1749 1750 return createLazyBinding(B, R); 1751} 1752 1753SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B, 1754 const TypedValueRegion *R) { 1755 assert(Ctx.getAsConstantArrayType(R->getValueType()) && 1756 "Only constant array types can have compound bindings."); 1757 1758 return createLazyBinding(B, R); 1759} 1760 1761bool RegionStoreManager::includedInBindings(Store store, 1762 const MemRegion *region) const { 1763 RegionBindingsRef B = getRegionBindings(store); 1764 region = region->getBaseRegion(); 1765 1766 // Quick path: if the base is the head of a cluster, the region is live. 1767 if (B.lookup(region)) 1768 return true; 1769 1770 // Slow path: if the region is the VALUE of any binding, it is live. 1771 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) { 1772 const ClusterBindings &Cluster = RI.getData(); 1773 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1774 CI != CE; ++CI) { 1775 const SVal &D = CI.getData(); 1776 if (const MemRegion *R = D.getAsRegion()) 1777 if (R->getBaseRegion() == region) 1778 return true; 1779 } 1780 } 1781 1782 return false; 1783} 1784 1785//===----------------------------------------------------------------------===// 1786// Binding values to regions. 1787//===----------------------------------------------------------------------===// 1788 1789StoreRef RegionStoreManager::killBinding(Store ST, Loc L) { 1790 if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>()) 1791 if (const MemRegion* R = LV->getRegion()) 1792 return StoreRef(getRegionBindings(ST).removeBinding(R) 1793 .asImmutableMap() 1794 .getRootWithoutRetain(), 1795 *this); 1796 1797 return StoreRef(ST, *this); 1798} 1799 1800RegionBindingsRef 1801RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) { 1802 if (L.getAs<loc::ConcreteInt>()) 1803 return B; 1804 1805 // If we get here, the location should be a region. 1806 const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion(); 1807 1808 // Check if the region is a struct region. 1809 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) { 1810 QualType Ty = TR->getValueType(); 1811 if (Ty->isArrayType()) 1812 return bindArray(B, TR, V); 1813 if (Ty->isStructureOrClassType()) 1814 return bindStruct(B, TR, V); 1815 if (Ty->isVectorType()) 1816 return bindVector(B, TR, V); 1817 } 1818 1819 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 1820 // Binding directly to a symbolic region should be treated as binding 1821 // to element 0. 1822 QualType T = SR->getSymbol()->getType(); 1823 if (T->isAnyPointerType() || T->isReferenceType()) 1824 T = T->getPointeeType(); 1825 1826 R = GetElementZeroRegion(SR, T); 1827 } 1828 1829 // Clear out bindings that may overlap with this binding. 1830 RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R)); 1831 return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V); 1832} 1833 1834// FIXME: this method should be merged into Bind(). 1835StoreRef RegionStoreManager::bindCompoundLiteral(Store ST, 1836 const CompoundLiteralExpr *CL, 1837 const LocationContext *LC, 1838 SVal V) { 1839 return Bind(ST, loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)), V); 1840} 1841 1842RegionBindingsRef 1843RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B, 1844 const MemRegion *R, 1845 QualType T) { 1846 SVal V; 1847 1848 if (Loc::isLocType(T)) 1849 V = svalBuilder.makeNull(); 1850 else if (T->isIntegerType()) 1851 V = svalBuilder.makeZeroVal(T); 1852 else if (T->isStructureOrClassType() || T->isArrayType()) { 1853 // Set the default value to a zero constant when it is a structure 1854 // or array. The type doesn't really matter. 1855 V = svalBuilder.makeZeroVal(Ctx.IntTy); 1856 } 1857 else { 1858 // We can't represent values of this type, but we still need to set a value 1859 // to record that the region has been initialized. 1860 // If this assertion ever fires, a new case should be added above -- we 1861 // should know how to default-initialize any value we can symbolicate. 1862 assert(!SymbolManager::canSymbolicate(T) && "This type is representable"); 1863 V = UnknownVal(); 1864 } 1865 1866 return B.addBinding(R, BindingKey::Default, V); 1867} 1868 1869RegionBindingsRef 1870RegionStoreManager::bindArray(RegionBindingsConstRef B, 1871 const TypedValueRegion* R, 1872 SVal Init) { 1873 1874 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType())); 1875 QualType ElementTy = AT->getElementType(); 1876 Optional<uint64_t> Size; 1877 1878 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT)) 1879 Size = CAT->getSize().getZExtValue(); 1880 1881 // Check if the init expr is a string literal. 1882 if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) { 1883 const StringRegion *S = cast<StringRegion>(MRV->getRegion()); 1884 1885 // Treat the string as a lazy compound value. 1886 StoreRef store(B.asStore(), *this); 1887 nonloc::LazyCompoundVal LCV = svalBuilder.makeLazyCompoundVal(store, S) 1888 .castAs<nonloc::LazyCompoundVal>(); 1889 return bindAggregate(B, R, LCV); 1890 } 1891 1892 // Handle lazy compound values. 1893 if (Init.getAs<nonloc::LazyCompoundVal>()) 1894 return bindAggregate(B, R, Init); 1895 1896 // Remaining case: explicit compound values. 1897 1898 if (Init.isUnknown()) 1899 return setImplicitDefaultValue(B, R, ElementTy); 1900 1901 const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>(); 1902 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1903 uint64_t i = 0; 1904 1905 RegionBindingsRef NewB(B); 1906 1907 for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) { 1908 // The init list might be shorter than the array length. 1909 if (VI == VE) 1910 break; 1911 1912 const NonLoc &Idx = svalBuilder.makeArrayIndex(i); 1913 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx); 1914 1915 if (ElementTy->isStructureOrClassType()) 1916 NewB = bindStruct(NewB, ER, *VI); 1917 else if (ElementTy->isArrayType()) 1918 NewB = bindArray(NewB, ER, *VI); 1919 else 1920 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1921 } 1922 1923 // If the init list is shorter than the array length, set the 1924 // array default value. 1925 if (Size.hasValue() && i < Size.getValue()) 1926 NewB = setImplicitDefaultValue(NewB, R, ElementTy); 1927 1928 return NewB; 1929} 1930 1931RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B, 1932 const TypedValueRegion* R, 1933 SVal V) { 1934 QualType T = R->getValueType(); 1935 assert(T->isVectorType()); 1936 const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs. 1937 1938 // Handle lazy compound values and symbolic values. 1939 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 1940 return bindAggregate(B, R, V); 1941 1942 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1943 // that we are binding symbolic struct value. Kill the field values, and if 1944 // the value is symbolic go and bind it as a "default" binding. 1945 if (!V.getAs<nonloc::CompoundVal>()) { 1946 return bindAggregate(B, R, UnknownVal()); 1947 } 1948 1949 QualType ElemType = VT->getElementType(); 1950 nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>(); 1951 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1952 unsigned index = 0, numElements = VT->getNumElements(); 1953 RegionBindingsRef NewB(B); 1954 1955 for ( ; index != numElements ; ++index) { 1956 if (VI == VE) 1957 break; 1958 1959 NonLoc Idx = svalBuilder.makeArrayIndex(index); 1960 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx); 1961 1962 if (ElemType->isArrayType()) 1963 NewB = bindArray(NewB, ER, *VI); 1964 else if (ElemType->isStructureOrClassType()) 1965 NewB = bindStruct(NewB, ER, *VI); 1966 else 1967 NewB = bind(NewB, svalBuilder.makeLoc(ER), *VI); 1968 } 1969 return NewB; 1970} 1971 1972RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B, 1973 const TypedValueRegion* R, 1974 SVal V) { 1975 if (!Features.supportsFields()) 1976 return B; 1977 1978 QualType T = R->getValueType(); 1979 assert(T->isStructureOrClassType()); 1980 1981 const RecordType* RT = T->getAs<RecordType>(); 1982 RecordDecl *RD = RT->getDecl(); 1983 1984 if (!RD->isCompleteDefinition()) 1985 return B; 1986 1987 // Handle lazy compound values and symbolic values. 1988 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 1989 return bindAggregate(B, R, V); 1990 1991 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1992 // that we are binding symbolic struct value. Kill the field values, and if 1993 // the value is symbolic go and bind it as a "default" binding. 1994 if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>()) 1995 return bindAggregate(B, R, UnknownVal()); 1996 1997 const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>(); 1998 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1999 2000 RecordDecl::field_iterator FI, FE; 2001 RegionBindingsRef NewB(B); 2002 2003 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) { 2004 2005 if (VI == VE) 2006 break; 2007 2008 // Skip any unnamed bitfields to stay in sync with the initializers. 2009 if (FI->isUnnamedBitfield()) 2010 continue; 2011 2012 QualType FTy = FI->getType(); 2013 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R); 2014 2015 if (FTy->isArrayType()) 2016 NewB = bindArray(NewB, FR, *VI); 2017 else if (FTy->isStructureOrClassType()) 2018 NewB = bindStruct(NewB, FR, *VI); 2019 else 2020 NewB = bind(NewB, svalBuilder.makeLoc(FR), *VI); 2021 ++VI; 2022 } 2023 2024 // There may be fewer values in the initialize list than the fields of struct. 2025 if (FI != FE) { 2026 NewB = NewB.addBinding(R, BindingKey::Default, 2027 svalBuilder.makeIntVal(0, false)); 2028 } 2029 2030 return NewB; 2031} 2032 2033RegionBindingsRef 2034RegionStoreManager::bindAggregate(RegionBindingsConstRef B, 2035 const TypedRegion *R, 2036 SVal Val) { 2037 // Remove the old bindings, using 'R' as the root of all regions 2038 // we will invalidate. Then add the new binding. 2039 return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val); 2040} 2041 2042//===----------------------------------------------------------------------===// 2043// State pruning. 2044//===----------------------------------------------------------------------===// 2045 2046namespace { 2047class removeDeadBindingsWorker : 2048 public ClusterAnalysis<removeDeadBindingsWorker> { 2049 SmallVector<const SymbolicRegion*, 12> Postponed; 2050 SymbolReaper &SymReaper; 2051 const StackFrameContext *CurrentLCtx; 2052 2053public: 2054 removeDeadBindingsWorker(RegionStoreManager &rm, 2055 ProgramStateManager &stateMgr, 2056 RegionBindingsRef b, SymbolReaper &symReaper, 2057 const StackFrameContext *LCtx) 2058 : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b, 2059 /* includeGlobals = */ false), 2060 SymReaper(symReaper), CurrentLCtx(LCtx) {} 2061 2062 // Called by ClusterAnalysis. 2063 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C); 2064 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C); 2065 using ClusterAnalysis<removeDeadBindingsWorker>::VisitCluster; 2066 2067 bool UpdatePostponed(); 2068 void VisitBinding(SVal V); 2069}; 2070} 2071 2072void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR, 2073 const ClusterBindings &C) { 2074 2075 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) { 2076 if (SymReaper.isLive(VR)) 2077 AddToWorkList(baseR, &C); 2078 2079 return; 2080 } 2081 2082 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 2083 if (SymReaper.isLive(SR->getSymbol())) 2084 AddToWorkList(SR, &C); 2085 else 2086 Postponed.push_back(SR); 2087 2088 return; 2089 } 2090 2091 if (isa<NonStaticGlobalSpaceRegion>(baseR)) { 2092 AddToWorkList(baseR, &C); 2093 return; 2094 } 2095 2096 // CXXThisRegion in the current or parent location context is live. 2097 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) { 2098 const StackArgumentsSpaceRegion *StackReg = 2099 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion()); 2100 const StackFrameContext *RegCtx = StackReg->getStackFrame(); 2101 if (CurrentLCtx && 2102 (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))) 2103 AddToWorkList(TR, &C); 2104 } 2105} 2106 2107void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR, 2108 const ClusterBindings *C) { 2109 if (!C) 2110 return; 2111 2112 // Mark the symbol for any SymbolicRegion with live bindings as live itself. 2113 // This means we should continue to track that symbol. 2114 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR)) 2115 SymReaper.markLive(SymR->getSymbol()); 2116 2117 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) 2118 VisitBinding(I.getData()); 2119} 2120 2121void removeDeadBindingsWorker::VisitBinding(SVal V) { 2122 // Is it a LazyCompoundVal? All referenced regions are live as well. 2123 if (Optional<nonloc::LazyCompoundVal> LCS = 2124 V.getAs<nonloc::LazyCompoundVal>()) { 2125 2126 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 2127 2128 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 2129 E = Vals.end(); 2130 I != E; ++I) 2131 VisitBinding(*I); 2132 2133 return; 2134 } 2135 2136 // If V is a region, then add it to the worklist. 2137 if (const MemRegion *R = V.getAsRegion()) { 2138 AddToWorkList(R); 2139 2140 // All regions captured by a block are also live. 2141 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) { 2142 BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(), 2143 E = BR->referenced_vars_end(); 2144 for ( ; I != E; ++I) 2145 AddToWorkList(I.getCapturedRegion()); 2146 } 2147 } 2148 2149 2150 // Update the set of live symbols. 2151 for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end(); 2152 SI!=SE; ++SI) 2153 SymReaper.markLive(*SI); 2154} 2155 2156bool removeDeadBindingsWorker::UpdatePostponed() { 2157 // See if any postponed SymbolicRegions are actually live now, after 2158 // having done a scan. 2159 bool changed = false; 2160 2161 for (SmallVectorImpl<const SymbolicRegion*>::iterator 2162 I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) { 2163 if (const SymbolicRegion *SR = *I) { 2164 if (SymReaper.isLive(SR->getSymbol())) { 2165 changed |= AddToWorkList(SR); 2166 *I = NULL; 2167 } 2168 } 2169 } 2170 2171 return changed; 2172} 2173 2174StoreRef RegionStoreManager::removeDeadBindings(Store store, 2175 const StackFrameContext *LCtx, 2176 SymbolReaper& SymReaper) { 2177 RegionBindingsRef B = getRegionBindings(store); 2178 removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx); 2179 W.GenerateClusters(); 2180 2181 // Enqueue the region roots onto the worklist. 2182 for (SymbolReaper::region_iterator I = SymReaper.region_begin(), 2183 E = SymReaper.region_end(); I != E; ++I) { 2184 W.AddToWorkList(*I); 2185 } 2186 2187 do W.RunWorkList(); while (W.UpdatePostponed()); 2188 2189 // We have now scanned the store, marking reachable regions and symbols 2190 // as live. We now remove all the regions that are dead from the store 2191 // as well as update DSymbols with the set symbols that are now dead. 2192 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 2193 const MemRegion *Base = I.getKey(); 2194 2195 // If the cluster has been visited, we know the region has been marked. 2196 if (W.isVisited(Base)) 2197 continue; 2198 2199 // Remove the dead entry. 2200 B = B.remove(Base); 2201 2202 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base)) 2203 SymReaper.maybeDead(SymR->getSymbol()); 2204 2205 // Mark all non-live symbols that this binding references as dead. 2206 const ClusterBindings &Cluster = I.getData(); 2207 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 2208 CI != CE; ++CI) { 2209 SVal X = CI.getData(); 2210 SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end(); 2211 for (; SI != SE; ++SI) 2212 SymReaper.maybeDead(*SI); 2213 } 2214 } 2215 2216 return StoreRef(B.asStore(), *this); 2217} 2218 2219//===----------------------------------------------------------------------===// 2220// Utility methods. 2221//===----------------------------------------------------------------------===// 2222 2223void RegionStoreManager::print(Store store, raw_ostream &OS, 2224 const char* nl, const char *sep) { 2225 RegionBindingsRef B = getRegionBindings(store); 2226 OS << "Store (direct and default bindings), " 2227 << B.asStore() 2228 << " :" << nl; 2229 B.dump(OS, nl); 2230} 2231