RegionStore.cpp revision d8dfae602d7b2e42b0eef6b1e7779c96833f83c1
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/AnalysisManager.h" 23#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 24#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 25#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" 26#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 27#include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h" 28#include "llvm/ADT/ImmutableList.h" 29#include "llvm/ADT/ImmutableMap.h" 30#include "llvm/ADT/Optional.h" 31#include "llvm/Support/raw_ostream.h" 32 33using namespace clang; 34using namespace ento; 35 36//===----------------------------------------------------------------------===// 37// Representation of binding keys. 38//===----------------------------------------------------------------------===// 39 40namespace { 41class BindingKey { 42public: 43 enum Kind { Default = 0x0, Direct = 0x1 }; 44private: 45 enum { Symbolic = 0x2 }; 46 47 llvm::PointerIntPair<const MemRegion *, 2> P; 48 uint64_t Data; 49 50 /// Create a key for a binding to region \p r, which has a symbolic offset 51 /// from region \p Base. 52 explicit BindingKey(const SubRegion *r, const SubRegion *Base, Kind k) 53 : P(r, k | Symbolic), Data(reinterpret_cast<uintptr_t>(Base)) { 54 assert(r && Base && "Must have known regions."); 55 assert(getConcreteOffsetRegion() == Base && "Failed to store base region"); 56 } 57 58 /// Create a key for a binding at \p offset from base region \p r. 59 explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k) 60 : P(r, k), Data(offset) { 61 assert(r && "Must have known regions."); 62 assert(getOffset() == offset && "Failed to store offset"); 63 assert((r == r->getBaseRegion() || isa<ObjCIvarRegion>(r)) && "Not a base"); 64 } 65public: 66 67 bool isDirect() const { return P.getInt() & Direct; } 68 bool hasSymbolicOffset() const { return P.getInt() & Symbolic; } 69 70 const MemRegion *getRegion() const { return P.getPointer(); } 71 uint64_t getOffset() const { 72 assert(!hasSymbolicOffset()); 73 return Data; 74 } 75 76 const SubRegion *getConcreteOffsetRegion() const { 77 assert(hasSymbolicOffset()); 78 return reinterpret_cast<const SubRegion *>(static_cast<uintptr_t>(Data)); 79 } 80 81 const MemRegion *getBaseRegion() const { 82 if (hasSymbolicOffset()) 83 return getConcreteOffsetRegion()->getBaseRegion(); 84 return getRegion()->getBaseRegion(); 85 } 86 87 void Profile(llvm::FoldingSetNodeID& ID) const { 88 ID.AddPointer(P.getOpaqueValue()); 89 ID.AddInteger(Data); 90 } 91 92 static BindingKey Make(const MemRegion *R, Kind k); 93 94 bool operator<(const BindingKey &X) const { 95 if (P.getOpaqueValue() < X.P.getOpaqueValue()) 96 return true; 97 if (P.getOpaqueValue() > X.P.getOpaqueValue()) 98 return false; 99 return Data < X.Data; 100 } 101 102 bool operator==(const BindingKey &X) const { 103 return P.getOpaqueValue() == X.P.getOpaqueValue() && 104 Data == X.Data; 105 } 106 107 LLVM_ATTRIBUTE_USED void dump() const; 108}; 109} // end anonymous namespace 110 111BindingKey BindingKey::Make(const MemRegion *R, Kind k) { 112 const RegionOffset &RO = R->getAsOffset(); 113 if (RO.hasSymbolicOffset()) 114 return BindingKey(cast<SubRegion>(R), cast<SubRegion>(RO.getRegion()), k); 115 116 return BindingKey(RO.getRegion(), RO.getOffset(), k); 117} 118 119namespace llvm { 120 static inline 121 raw_ostream &operator<<(raw_ostream &os, BindingKey K) { 122 os << '(' << K.getRegion(); 123 if (!K.hasSymbolicOffset()) 124 os << ',' << K.getOffset(); 125 os << ',' << (K.isDirect() ? "direct" : "default") 126 << ')'; 127 return os; 128 } 129 130 template <typename T> struct isPodLike; 131 template <> struct isPodLike<BindingKey> { 132 static const bool value = true; 133 }; 134} // end llvm namespace 135 136void BindingKey::dump() const { 137 llvm::errs() << *this; 138} 139 140//===----------------------------------------------------------------------===// 141// Actual Store type. 142//===----------------------------------------------------------------------===// 143 144typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings; 145typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef; 146typedef std::pair<BindingKey, SVal> BindingPair; 147 148typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings> 149 RegionBindings; 150 151namespace { 152class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *, 153 ClusterBindings> { 154 ClusterBindings::Factory &CBFactory; 155public: 156 typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings> 157 ParentTy; 158 159 RegionBindingsRef(ClusterBindings::Factory &CBFactory, 160 const RegionBindings::TreeTy *T, 161 RegionBindings::TreeTy::Factory *F) 162 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F), 163 CBFactory(CBFactory) {} 164 165 RegionBindingsRef(const ParentTy &P, ClusterBindings::Factory &CBFactory) 166 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P), 167 CBFactory(CBFactory) {} 168 169 RegionBindingsRef add(key_type_ref K, data_type_ref D) const { 170 return RegionBindingsRef(static_cast<const ParentTy*>(this)->add(K, D), 171 CBFactory); 172 } 173 174 RegionBindingsRef remove(key_type_ref K) const { 175 return RegionBindingsRef(static_cast<const ParentTy*>(this)->remove(K), 176 CBFactory); 177 } 178 179 RegionBindingsRef addBinding(BindingKey K, SVal V) const; 180 181 RegionBindingsRef addBinding(const MemRegion *R, 182 BindingKey::Kind k, SVal V) const; 183 184 RegionBindingsRef &operator=(const RegionBindingsRef &X) { 185 *static_cast<ParentTy*>(this) = X; 186 return *this; 187 } 188 189 const SVal *lookup(BindingKey K) const; 190 const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const; 191 const ClusterBindings *lookup(const MemRegion *R) const { 192 return static_cast<const ParentTy*>(this)->lookup(R); 193 } 194 195 RegionBindingsRef removeBinding(BindingKey K); 196 197 RegionBindingsRef removeBinding(const MemRegion *R, 198 BindingKey::Kind k); 199 200 RegionBindingsRef removeBinding(const MemRegion *R) { 201 return removeBinding(R, BindingKey::Direct). 202 removeBinding(R, BindingKey::Default); 203 } 204 205 Optional<SVal> getDirectBinding(const MemRegion *R) const; 206 207 /// getDefaultBinding - Returns an SVal* representing an optional default 208 /// binding associated with a region and its subregions. 209 Optional<SVal> getDefaultBinding(const MemRegion *R) const; 210 211 /// Return the internal tree as a Store. 212 Store asStore() const { 213 return asImmutableMap().getRootWithoutRetain(); 214 } 215 216 void dump(raw_ostream &OS, const char *nl) const { 217 for (iterator I = begin(), E = end(); I != E; ++I) { 218 const ClusterBindings &Cluster = I.getData(); 219 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 220 CI != CE; ++CI) { 221 OS << ' ' << CI.getKey() << " : " << CI.getData() << nl; 222 } 223 OS << nl; 224 } 225 } 226 227 LLVM_ATTRIBUTE_USED void dump() const { 228 dump(llvm::errs(), "\n"); 229 } 230}; 231} // end anonymous namespace 232 233typedef const RegionBindingsRef& RegionBindingsConstRef; 234 235Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const { 236 return Optional<SVal>::create(lookup(R, BindingKey::Direct)); 237} 238 239Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const { 240 if (R->isBoundable()) 241 if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) 242 if (TR->getValueType()->isUnionType()) 243 return UnknownVal(); 244 245 return Optional<SVal>::create(lookup(R, BindingKey::Default)); 246} 247 248RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const { 249 const MemRegion *Base = K.getBaseRegion(); 250 251 const ClusterBindings *ExistingCluster = lookup(Base); 252 ClusterBindings Cluster = (ExistingCluster ? *ExistingCluster 253 : CBFactory.getEmptyMap()); 254 255 ClusterBindings NewCluster = CBFactory.add(Cluster, K, V); 256 return add(Base, NewCluster); 257} 258 259 260RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R, 261 BindingKey::Kind k, 262 SVal V) const { 263 return addBinding(BindingKey::Make(R, k), V); 264} 265 266const SVal *RegionBindingsRef::lookup(BindingKey K) const { 267 const ClusterBindings *Cluster = lookup(K.getBaseRegion()); 268 if (!Cluster) 269 return 0; 270 return Cluster->lookup(K); 271} 272 273const SVal *RegionBindingsRef::lookup(const MemRegion *R, 274 BindingKey::Kind k) const { 275 return lookup(BindingKey::Make(R, k)); 276} 277 278RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) { 279 const MemRegion *Base = K.getBaseRegion(); 280 const ClusterBindings *Cluster = lookup(Base); 281 if (!Cluster) 282 return *this; 283 284 ClusterBindings NewCluster = CBFactory.remove(*Cluster, K); 285 if (NewCluster.isEmpty()) 286 return remove(Base); 287 return add(Base, NewCluster); 288} 289 290RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R, 291 BindingKey::Kind k){ 292 return removeBinding(BindingKey::Make(R, k)); 293} 294 295//===----------------------------------------------------------------------===// 296// Fine-grained control of RegionStoreManager. 297//===----------------------------------------------------------------------===// 298 299namespace { 300struct minimal_features_tag {}; 301struct maximal_features_tag {}; 302 303class RegionStoreFeatures { 304 bool SupportsFields; 305public: 306 RegionStoreFeatures(minimal_features_tag) : 307 SupportsFields(false) {} 308 309 RegionStoreFeatures(maximal_features_tag) : 310 SupportsFields(true) {} 311 312 void enableFields(bool t) { SupportsFields = t; } 313 314 bool supportsFields() const { return SupportsFields; } 315}; 316} 317 318//===----------------------------------------------------------------------===// 319// Main RegionStore logic. 320//===----------------------------------------------------------------------===// 321 322namespace { 323class invalidateRegionsWorker; 324 325class RegionStoreManager : public StoreManager { 326public: 327 const RegionStoreFeatures Features; 328 329 RegionBindings::Factory RBFactory; 330 mutable ClusterBindings::Factory CBFactory; 331 332 typedef std::vector<SVal> SValListTy; 333private: 334 typedef llvm::DenseMap<const LazyCompoundValData *, 335 SValListTy> LazyBindingsMapTy; 336 LazyBindingsMapTy LazyBindingsMap; 337 338 /// The largest number of fields a struct can have and still be 339 /// considered "small". 340 /// 341 /// This is currently used to decide whether or not it is worth "forcing" a 342 /// LazyCompoundVal on bind. 343 /// 344 /// This is controlled by 'region-store-small-struct-limit' option. 345 /// To disable all small-struct-dependent behavior, set the option to "0". 346 unsigned SmallStructLimit; 347 348 /// \brief A helper used to populate the work list with the given set of 349 /// regions. 350 void populateWorkList(invalidateRegionsWorker &W, 351 ArrayRef<SVal> Values, 352 bool IsArrayOfConstRegions, 353 InvalidatedRegions *TopLevelRegions); 354 355public: 356 RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f) 357 : StoreManager(mgr), Features(f), 358 RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()), 359 SmallStructLimit(0) { 360 if (SubEngine *Eng = StateMgr.getOwningEngine()) { 361 AnalyzerOptions &Options = Eng->getAnalysisManager().options; 362 SmallStructLimit = 363 Options.getOptionAsInteger("region-store-small-struct-limit", 2); 364 } 365 } 366 367 368 /// setImplicitDefaultValue - Set the default binding for the provided 369 /// MemRegion to the value implicitly defined for compound literals when 370 /// the value is not specified. 371 RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B, 372 const MemRegion *R, QualType T); 373 374 /// ArrayToPointer - Emulates the "decay" of an array to a pointer 375 /// type. 'Array' represents the lvalue of the array being decayed 376 /// to a pointer, and the returned SVal represents the decayed 377 /// version of that lvalue (i.e., a pointer to the first element of 378 /// the array). This is called by ExprEngine when evaluating 379 /// casts from arrays to pointers. 380 SVal ArrayToPointer(Loc Array, QualType ElementTy); 381 382 StoreRef getInitialStore(const LocationContext *InitLoc) { 383 return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this); 384 } 385 386 //===-------------------------------------------------------------------===// 387 // Binding values to regions. 388 //===-------------------------------------------------------------------===// 389 RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K, 390 const Expr *Ex, 391 unsigned Count, 392 const LocationContext *LCtx, 393 RegionBindingsRef B, 394 InvalidatedRegions *Invalidated); 395 396 StoreRef invalidateRegions(Store store, 397 ArrayRef<SVal> Values, 398 ArrayRef<SVal> ConstValues, 399 const Expr *E, unsigned Count, 400 const LocationContext *LCtx, 401 const CallEvent *Call, 402 InvalidatedSymbols &IS, 403 InvalidatedSymbols &ConstIS, 404 InvalidatedRegions *Invalidated, 405 InvalidatedRegions *InvalidatedTopLevel, 406 InvalidatedRegions *InvalidatedTopLevelConst); 407 408 bool scanReachableSymbols(Store S, const MemRegion *R, 409 ScanReachableSymbols &Callbacks); 410 411 RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B, 412 const SubRegion *R); 413 414public: // Part of public interface to class. 415 416 virtual StoreRef Bind(Store store, Loc LV, SVal V) { 417 return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this); 418 } 419 420 RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V); 421 422 // BindDefault is only used to initialize a region with a default value. 423 StoreRef BindDefault(Store store, const MemRegion *R, SVal V) { 424 RegionBindingsRef B = getRegionBindings(store); 425 assert(!B.lookup(R, BindingKey::Direct)); 426 427 BindingKey Key = BindingKey::Make(R, BindingKey::Default); 428 if (B.lookup(Key)) { 429 const SubRegion *SR = cast<SubRegion>(R); 430 assert(SR->getAsOffset().getOffset() == 431 SR->getSuperRegion()->getAsOffset().getOffset() && 432 "A default value must come from a super-region"); 433 B = removeSubRegionBindings(B, SR); 434 } else { 435 B = B.addBinding(Key, V); 436 } 437 438 return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this); 439 } 440 441 /// Attempt to extract the fields of \p LCV and bind them to the struct region 442 /// \p R. 443 /// 444 /// This path is used when it seems advantageous to "force" loading the values 445 /// within a LazyCompoundVal to bind memberwise to the struct region, rather 446 /// than using a Default binding at the base of the entire region. This is a 447 /// heuristic attempting to avoid building long chains of LazyCompoundVals. 448 /// 449 /// \returns The updated store bindings, or \c None if binding non-lazily 450 /// would be too expensive. 451 Optional<RegionBindingsRef> tryBindSmallStruct(RegionBindingsConstRef B, 452 const TypedValueRegion *R, 453 const RecordDecl *RD, 454 nonloc::LazyCompoundVal LCV); 455 456 /// BindStruct - Bind a compound value to a structure. 457 RegionBindingsRef bindStruct(RegionBindingsConstRef B, 458 const TypedValueRegion* R, SVal V); 459 460 /// BindVector - Bind a compound value to a vector. 461 RegionBindingsRef bindVector(RegionBindingsConstRef B, 462 const TypedValueRegion* R, SVal V); 463 464 RegionBindingsRef bindArray(RegionBindingsConstRef B, 465 const TypedValueRegion* R, 466 SVal V); 467 468 /// Clears out all bindings in the given region and assigns a new value 469 /// as a Default binding. 470 RegionBindingsRef bindAggregate(RegionBindingsConstRef B, 471 const TypedRegion *R, 472 SVal DefaultVal); 473 474 /// \brief Create a new store with the specified binding removed. 475 /// \param ST the original store, that is the basis for the new store. 476 /// \param L the location whose binding should be removed. 477 virtual StoreRef killBinding(Store ST, Loc L); 478 479 void incrementReferenceCount(Store store) { 480 getRegionBindings(store).manualRetain(); 481 } 482 483 /// If the StoreManager supports it, decrement the reference count of 484 /// the specified Store object. If the reference count hits 0, the memory 485 /// associated with the object is recycled. 486 void decrementReferenceCount(Store store) { 487 getRegionBindings(store).manualRelease(); 488 } 489 490 bool includedInBindings(Store store, const MemRegion *region) const; 491 492 /// \brief Return the value bound to specified location in a given state. 493 /// 494 /// The high level logic for this method is this: 495 /// getBinding (L) 496 /// if L has binding 497 /// return L's binding 498 /// else if L is in killset 499 /// return unknown 500 /// else 501 /// if L is on stack or heap 502 /// return undefined 503 /// else 504 /// return symbolic 505 virtual SVal getBinding(Store S, Loc L, QualType T) { 506 return getBinding(getRegionBindings(S), L, T); 507 } 508 509 SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType()); 510 511 SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R); 512 513 SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R); 514 515 SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R); 516 517 SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R); 518 519 SVal getBindingForLazySymbol(const TypedValueRegion *R); 520 521 SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 522 const TypedValueRegion *R, 523 QualType Ty); 524 525 SVal getLazyBinding(const SubRegion *LazyBindingRegion, 526 RegionBindingsRef LazyBinding); 527 528 /// Get bindings for the values in a struct and return a CompoundVal, used 529 /// when doing struct copy: 530 /// struct s x, y; 531 /// x = y; 532 /// y's value is retrieved by this method. 533 SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R); 534 SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R); 535 NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R); 536 537 /// Used to lazily generate derived symbols for bindings that are defined 538 /// implicitly by default bindings in a super region. 539 /// 540 /// Note that callers may need to specially handle LazyCompoundVals, which 541 /// are returned as is in case the caller needs to treat them differently. 542 Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 543 const MemRegion *superR, 544 const TypedValueRegion *R, 545 QualType Ty); 546 547 /// Get the state and region whose binding this region \p R corresponds to. 548 /// 549 /// If there is no lazy binding for \p R, the returned value will have a null 550 /// \c second. Note that a null pointer can represents a valid Store. 551 std::pair<Store, const SubRegion *> 552 findLazyBinding(RegionBindingsConstRef B, const SubRegion *R, 553 const SubRegion *originalRegion); 554 555 /// Returns the cached set of interesting SVals contained within a lazy 556 /// binding. 557 /// 558 /// The precise value of "interesting" is determined for the purposes of 559 /// RegionStore's internal analysis. It must always contain all regions and 560 /// symbols, but may omit constants and other kinds of SVal. 561 const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV); 562 563 //===------------------------------------------------------------------===// 564 // State pruning. 565 //===------------------------------------------------------------------===// 566 567 /// removeDeadBindings - Scans the RegionStore of 'state' for dead values. 568 /// It returns a new Store with these values removed. 569 StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, 570 SymbolReaper& SymReaper); 571 572 //===------------------------------------------------------------------===// 573 // Region "extents". 574 //===------------------------------------------------------------------===// 575 576 // FIXME: This method will soon be eliminated; see the note in Store.h. 577 DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state, 578 const MemRegion* R, QualType EleTy); 579 580 //===------------------------------------------------------------------===// 581 // Utility methods. 582 //===------------------------------------------------------------------===// 583 584 RegionBindingsRef getRegionBindings(Store store) const { 585 return RegionBindingsRef(CBFactory, 586 static_cast<const RegionBindings::TreeTy*>(store), 587 RBFactory.getTreeFactory()); 588 } 589 590 void print(Store store, raw_ostream &Out, const char* nl, 591 const char *sep); 592 593 void iterBindings(Store store, BindingsHandler& f) { 594 RegionBindingsRef B = getRegionBindings(store); 595 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 596 const ClusterBindings &Cluster = I.getData(); 597 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 598 CI != CE; ++CI) { 599 const BindingKey &K = CI.getKey(); 600 if (!K.isDirect()) 601 continue; 602 if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) { 603 // FIXME: Possibly incorporate the offset? 604 if (!f.HandleBinding(*this, store, R, CI.getData())) 605 return; 606 } 607 } 608 } 609 } 610}; 611 612} // end anonymous namespace 613 614//===----------------------------------------------------------------------===// 615// RegionStore creation. 616//===----------------------------------------------------------------------===// 617 618StoreManager *ento::CreateRegionStoreManager(ProgramStateManager& StMgr) { 619 RegionStoreFeatures F = maximal_features_tag(); 620 return new RegionStoreManager(StMgr, F); 621} 622 623StoreManager * 624ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) { 625 RegionStoreFeatures F = minimal_features_tag(); 626 F.enableFields(true); 627 return new RegionStoreManager(StMgr, F); 628} 629 630 631//===----------------------------------------------------------------------===// 632// Region Cluster analysis. 633//===----------------------------------------------------------------------===// 634 635namespace { 636/// Used to determine which global regions are automatically included in the 637/// initial worklist of a ClusterAnalysis. 638enum GlobalsFilterKind { 639 /// Don't include any global regions. 640 GFK_None, 641 /// Only include system globals. 642 GFK_SystemOnly, 643 /// Include all global regions. 644 GFK_All 645}; 646 647template <typename DERIVED> 648class ClusterAnalysis { 649protected: 650 typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap; 651 typedef llvm::PointerIntPair<const MemRegion *, 1, bool> WorkListElement; 652 typedef SmallVector<WorkListElement, 10> WorkList; 653 654 llvm::SmallPtrSet<const ClusterBindings *, 16> Visited; 655 656 WorkList WL; 657 658 RegionStoreManager &RM; 659 ASTContext &Ctx; 660 SValBuilder &svalBuilder; 661 662 RegionBindingsRef B; 663 664private: 665 GlobalsFilterKind GlobalsFilter; 666 667protected: 668 const ClusterBindings *getCluster(const MemRegion *R) { 669 return B.lookup(R); 670 } 671 672 /// Returns true if the memory space of the given region is one of the global 673 /// regions specially included at the start of analysis. 674 bool isInitiallyIncludedGlobalRegion(const MemRegion *R) { 675 switch (GlobalsFilter) { 676 case GFK_None: 677 return false; 678 case GFK_SystemOnly: 679 return isa<GlobalSystemSpaceRegion>(R->getMemorySpace()); 680 case GFK_All: 681 return isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace()); 682 } 683 684 llvm_unreachable("unknown globals filter"); 685 } 686 687public: 688 ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr, 689 RegionBindingsRef b, GlobalsFilterKind GFK) 690 : RM(rm), Ctx(StateMgr.getContext()), 691 svalBuilder(StateMgr.getSValBuilder()), 692 B(b), GlobalsFilter(GFK) {} 693 694 RegionBindingsRef getRegionBindings() const { return B; } 695 696 bool isVisited(const MemRegion *R) { 697 return Visited.count(getCluster(R)); 698 } 699 700 void GenerateClusters() { 701 // Scan the entire set of bindings and record the region clusters. 702 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); 703 RI != RE; ++RI){ 704 const MemRegion *Base = RI.getKey(); 705 706 const ClusterBindings &Cluster = RI.getData(); 707 assert(!Cluster.isEmpty() && "Empty clusters should be removed"); 708 static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster); 709 710 // If this is an interesting global region, add it the work list up front. 711 if (isInitiallyIncludedGlobalRegion(Base)) 712 AddToWorkList(WorkListElement(Base), &Cluster); 713 } 714 } 715 716 bool AddToWorkList(WorkListElement E, const ClusterBindings *C) { 717 if (C && !Visited.insert(C)) 718 return false; 719 WL.push_back(E); 720 return true; 721 } 722 723 bool AddToWorkList(const MemRegion *R, bool Flag = false) { 724 const MemRegion *BaseR = R->getBaseRegion(); 725 return AddToWorkList(WorkListElement(BaseR, Flag), getCluster(BaseR)); 726 } 727 728 void RunWorkList() { 729 while (!WL.empty()) { 730 WorkListElement E = WL.pop_back_val(); 731 const MemRegion *BaseR = E.getPointer(); 732 733 static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR), 734 E.getInt()); 735 } 736 } 737 738 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {} 739 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {} 740 741 void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C, 742 bool Flag) { 743 static_cast<DERIVED*>(this)->VisitCluster(BaseR, C); 744 } 745}; 746} 747 748//===----------------------------------------------------------------------===// 749// Binding invalidation. 750//===----------------------------------------------------------------------===// 751 752bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R, 753 ScanReachableSymbols &Callbacks) { 754 assert(R == R->getBaseRegion() && "Should only be called for base regions"); 755 RegionBindingsRef B = getRegionBindings(S); 756 const ClusterBindings *Cluster = B.lookup(R); 757 758 if (!Cluster) 759 return true; 760 761 for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end(); 762 RI != RE; ++RI) { 763 if (!Callbacks.scan(RI.getData())) 764 return false; 765 } 766 767 return true; 768} 769 770static inline bool isUnionField(const FieldRegion *FR) { 771 return FR->getDecl()->getParent()->isUnion(); 772} 773 774typedef SmallVector<const FieldDecl *, 8> FieldVector; 775 776void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) { 777 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 778 779 const MemRegion *Base = K.getConcreteOffsetRegion(); 780 const MemRegion *R = K.getRegion(); 781 782 while (R != Base) { 783 if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) 784 if (!isUnionField(FR)) 785 Fields.push_back(FR->getDecl()); 786 787 R = cast<SubRegion>(R)->getSuperRegion(); 788 } 789} 790 791static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) { 792 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 793 794 if (Fields.empty()) 795 return true; 796 797 FieldVector FieldsInBindingKey; 798 getSymbolicOffsetFields(K, FieldsInBindingKey); 799 800 ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size(); 801 if (Delta >= 0) 802 return std::equal(FieldsInBindingKey.begin() + Delta, 803 FieldsInBindingKey.end(), 804 Fields.begin()); 805 else 806 return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(), 807 Fields.begin() - Delta); 808} 809 810/// Collects all bindings in \p Cluster that may refer to bindings within 811/// \p Top. 812/// 813/// Each binding is a pair whose \c first is the key (a BindingKey) and whose 814/// \c second is the value (an SVal). 815/// 816/// The \p IncludeAllDefaultBindings parameter specifies whether to include 817/// default bindings that may extend beyond \p Top itself, e.g. if \p Top is 818/// an aggregate within a larger aggregate with a default binding. 819static void 820collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 821 SValBuilder &SVB, const ClusterBindings &Cluster, 822 const SubRegion *Top, BindingKey TopKey, 823 bool IncludeAllDefaultBindings) { 824 FieldVector FieldsInSymbolicSubregions; 825 if (TopKey.hasSymbolicOffset()) { 826 getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions); 827 Top = cast<SubRegion>(TopKey.getConcreteOffsetRegion()); 828 TopKey = BindingKey::Make(Top, BindingKey::Default); 829 } 830 831 // Find the length (in bits) of the region being invalidated. 832 uint64_t Length = UINT64_MAX; 833 SVal Extent = Top->getExtent(SVB); 834 if (Optional<nonloc::ConcreteInt> ExtentCI = 835 Extent.getAs<nonloc::ConcreteInt>()) { 836 const llvm::APSInt &ExtentInt = ExtentCI->getValue(); 837 assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned()); 838 // Extents are in bytes but region offsets are in bits. Be careful! 839 Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth(); 840 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) { 841 if (FR->getDecl()->isBitField()) 842 Length = FR->getDecl()->getBitWidthValue(SVB.getContext()); 843 } 844 845 for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end(); 846 I != E; ++I) { 847 BindingKey NextKey = I.getKey(); 848 if (NextKey.getRegion() == TopKey.getRegion()) { 849 // FIXME: This doesn't catch the case where we're really invalidating a 850 // region with a symbolic offset. Example: 851 // R: points[i].y 852 // Next: points[0].x 853 854 if (NextKey.getOffset() > TopKey.getOffset() && 855 NextKey.getOffset() - TopKey.getOffset() < Length) { 856 // Case 1: The next binding is inside the region we're invalidating. 857 // Include it. 858 Bindings.push_back(*I); 859 860 } else if (NextKey.getOffset() == TopKey.getOffset()) { 861 // Case 2: The next binding is at the same offset as the region we're 862 // invalidating. In this case, we need to leave default bindings alone, 863 // since they may be providing a default value for a regions beyond what 864 // we're invalidating. 865 // FIXME: This is probably incorrect; consider invalidating an outer 866 // struct whose first field is bound to a LazyCompoundVal. 867 if (IncludeAllDefaultBindings || NextKey.isDirect()) 868 Bindings.push_back(*I); 869 } 870 871 } else if (NextKey.hasSymbolicOffset()) { 872 const MemRegion *Base = NextKey.getConcreteOffsetRegion(); 873 if (Top->isSubRegionOf(Base)) { 874 // Case 3: The next key is symbolic and we just changed something within 875 // its concrete region. We don't know if the binding is still valid, so 876 // we'll be conservative and include it. 877 if (IncludeAllDefaultBindings || NextKey.isDirect()) 878 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 879 Bindings.push_back(*I); 880 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) { 881 // Case 4: The next key is symbolic, but we changed a known 882 // super-region. In this case the binding is certainly included. 883 if (Top == Base || BaseSR->isSubRegionOf(Top)) 884 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 885 Bindings.push_back(*I); 886 } 887 } 888 } 889} 890 891static void 892collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 893 SValBuilder &SVB, const ClusterBindings &Cluster, 894 const SubRegion *Top, bool IncludeAllDefaultBindings) { 895 collectSubRegionBindings(Bindings, SVB, Cluster, Top, 896 BindingKey::Make(Top, BindingKey::Default), 897 IncludeAllDefaultBindings); 898} 899 900RegionBindingsRef 901RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B, 902 const SubRegion *Top) { 903 BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default); 904 const MemRegion *ClusterHead = TopKey.getBaseRegion(); 905 906 if (Top == ClusterHead) { 907 // We can remove an entire cluster's bindings all in one go. 908 return B.remove(Top); 909 } 910 911 const ClusterBindings *Cluster = B.lookup(ClusterHead); 912 if (!Cluster) { 913 // If we're invalidating a region with a symbolic offset, we need to make 914 // sure we don't treat the base region as uninitialized anymore. 915 if (TopKey.hasSymbolicOffset()) { 916 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 917 return B.addBinding(Concrete, BindingKey::Default, UnknownVal()); 918 } 919 return B; 920 } 921 922 SmallVector<BindingPair, 32> Bindings; 923 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey, 924 /*IncludeAllDefaultBindings=*/false); 925 926 ClusterBindingsRef Result(*Cluster, CBFactory); 927 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 928 E = Bindings.end(); 929 I != E; ++I) 930 Result = Result.remove(I->first); 931 932 // If we're invalidating a region with a symbolic offset, we need to make sure 933 // we don't treat the base region as uninitialized anymore. 934 // FIXME: This isn't very precise; see the example in 935 // collectSubRegionBindings. 936 if (TopKey.hasSymbolicOffset()) { 937 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 938 Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default), 939 UnknownVal()); 940 } 941 942 if (Result.isEmpty()) 943 return B.remove(ClusterHead); 944 return B.add(ClusterHead, Result.asImmutableMap()); 945} 946 947namespace { 948class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker> 949{ 950 const Expr *Ex; 951 unsigned Count; 952 const LocationContext *LCtx; 953 InvalidatedSymbols &IS; 954 InvalidatedSymbols &ConstIS; 955 StoreManager::InvalidatedRegions *Regions; 956public: 957 invalidateRegionsWorker(RegionStoreManager &rm, 958 ProgramStateManager &stateMgr, 959 RegionBindingsRef b, 960 const Expr *ex, unsigned count, 961 const LocationContext *lctx, 962 InvalidatedSymbols &is, 963 InvalidatedSymbols &inConstIS, 964 StoreManager::InvalidatedRegions *r, 965 GlobalsFilterKind GFK) 966 : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, GFK), 967 Ex(ex), Count(count), LCtx(lctx), IS(is), ConstIS(inConstIS), Regions(r){} 968 969 /// \param IsConst Specifies if the region we are invalidating is constant. 970 /// If it is, we invalidate all subregions, but not the base region itself. 971 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C, 972 bool IsConst); 973 void VisitBinding(SVal V); 974}; 975} 976 977void invalidateRegionsWorker::VisitBinding(SVal V) { 978 // A symbol? Mark it touched by the invalidation. 979 if (SymbolRef Sym = V.getAsSymbol()) 980 IS.insert(Sym); 981 982 if (const MemRegion *R = V.getAsRegion()) { 983 AddToWorkList(R); 984 return; 985 } 986 987 // Is it a LazyCompoundVal? All references get invalidated as well. 988 if (Optional<nonloc::LazyCompoundVal> LCS = 989 V.getAs<nonloc::LazyCompoundVal>()) { 990 991 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 992 993 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 994 E = Vals.end(); 995 I != E; ++I) 996 VisitBinding(*I); 997 998 return; 999 } 1000} 1001 1002void invalidateRegionsWorker::VisitCluster(const MemRegion *baseR, 1003 const ClusterBindings *C, 1004 bool IsConst) { 1005 if (C) { 1006 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) 1007 VisitBinding(I.getData()); 1008 1009 // Invalidate the contents of a non-const base region. 1010 if (!IsConst) 1011 B = B.remove(baseR); 1012 } 1013 1014 // BlockDataRegion? If so, invalidate captured variables that are passed 1015 // by reference. 1016 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) { 1017 for (BlockDataRegion::referenced_vars_iterator 1018 BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ; 1019 BI != BE; ++BI) { 1020 const VarRegion *VR = BI.getCapturedRegion(); 1021 const VarDecl *VD = VR->getDecl(); 1022 if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage()) { 1023 AddToWorkList(VR); 1024 } 1025 else if (Loc::isLocType(VR->getValueType())) { 1026 // Map the current bindings to a Store to retrieve the value 1027 // of the binding. If that binding itself is a region, we should 1028 // invalidate that region. This is because a block may capture 1029 // a pointer value, but the thing pointed by that pointer may 1030 // get invalidated. 1031 SVal V = RM.getBinding(B, loc::MemRegionVal(VR)); 1032 if (Optional<Loc> L = V.getAs<Loc>()) { 1033 if (const MemRegion *LR = L->getAsRegion()) 1034 AddToWorkList(LR); 1035 } 1036 } 1037 } 1038 return; 1039 } 1040 1041 // Symbolic region? 1042 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 1043 SymbolRef RegionSym = SR->getSymbol(); 1044 1045 // Mark that symbol touched by the invalidation. 1046 if (IsConst) 1047 ConstIS.insert(RegionSym); 1048 else 1049 IS.insert(RegionSym); 1050 } 1051 1052 // Nothing else should be done for a const region. 1053 if (IsConst) 1054 return; 1055 1056 // Otherwise, we have a normal data region. Record that we touched the region. 1057 if (Regions) 1058 Regions->push_back(baseR); 1059 1060 if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) { 1061 // Invalidate the region by setting its default value to 1062 // conjured symbol. The type of the symbol is irrelavant. 1063 DefinedOrUnknownSVal V = 1064 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count); 1065 B = B.addBinding(baseR, BindingKey::Default, V); 1066 return; 1067 } 1068 1069 if (!baseR->isBoundable()) 1070 return; 1071 1072 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR); 1073 QualType T = TR->getValueType(); 1074 1075 if (isInitiallyIncludedGlobalRegion(baseR)) { 1076 // If the region is a global and we are invalidating all globals, 1077 // erasing the entry is good enough. This causes all globals to be lazily 1078 // symbolicated from the same base symbol. 1079 return; 1080 } 1081 1082 if (T->isStructureOrClassType()) { 1083 // Invalidate the region by setting its default value to 1084 // conjured symbol. The type of the symbol is irrelavant. 1085 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1086 Ctx.IntTy, Count); 1087 B = B.addBinding(baseR, BindingKey::Default, V); 1088 return; 1089 } 1090 1091 if (const ArrayType *AT = Ctx.getAsArrayType(T)) { 1092 // Set the default value of the array to conjured symbol. 1093 DefinedOrUnknownSVal V = 1094 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1095 AT->getElementType(), Count); 1096 B = B.addBinding(baseR, BindingKey::Default, V); 1097 return; 1098 } 1099 1100 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1101 T,Count); 1102 assert(SymbolManager::canSymbolicate(T) || V.isUnknown()); 1103 B = B.addBinding(baseR, BindingKey::Direct, V); 1104} 1105 1106RegionBindingsRef 1107RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K, 1108 const Expr *Ex, 1109 unsigned Count, 1110 const LocationContext *LCtx, 1111 RegionBindingsRef B, 1112 InvalidatedRegions *Invalidated) { 1113 // Bind the globals memory space to a new symbol that we will use to derive 1114 // the bindings for all globals. 1115 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K); 1116 SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx, 1117 /* type does not matter */ Ctx.IntTy, 1118 Count); 1119 1120 B = B.removeBinding(GS) 1121 .addBinding(BindingKey::Make(GS, BindingKey::Default), V); 1122 1123 // Even if there are no bindings in the global scope, we still need to 1124 // record that we touched it. 1125 if (Invalidated) 1126 Invalidated->push_back(GS); 1127 1128 return B; 1129} 1130 1131void RegionStoreManager::populateWorkList(invalidateRegionsWorker &W, 1132 ArrayRef<SVal> Values, 1133 bool IsArrayOfConstRegions, 1134 InvalidatedRegions *TopLevelRegions) { 1135 for (ArrayRef<SVal>::iterator I = Values.begin(), 1136 E = Values.end(); I != E; ++I) { 1137 SVal V = *I; 1138 if (Optional<nonloc::LazyCompoundVal> LCS = 1139 V.getAs<nonloc::LazyCompoundVal>()) { 1140 1141 const SValListTy &Vals = getInterestingValues(*LCS); 1142 1143 for (SValListTy::const_iterator I = Vals.begin(), 1144 E = Vals.end(); I != E; ++I) { 1145 // Note: the last argument is false here because these are 1146 // non-top-level regions. 1147 if (const MemRegion *R = (*I).getAsRegion()) 1148 W.AddToWorkList(R, /*IsConst=*/ false); 1149 } 1150 continue; 1151 } 1152 1153 if (const MemRegion *R = V.getAsRegion()) { 1154 if (TopLevelRegions) 1155 TopLevelRegions->push_back(R); 1156 W.AddToWorkList(R, /*IsConst=*/ IsArrayOfConstRegions); 1157 continue; 1158 } 1159 } 1160} 1161 1162StoreRef 1163RegionStoreManager::invalidateRegions(Store store, 1164 ArrayRef<SVal> Values, 1165 ArrayRef<SVal> ConstValues, 1166 const Expr *Ex, unsigned Count, 1167 const LocationContext *LCtx, 1168 const CallEvent *Call, 1169 InvalidatedSymbols &IS, 1170 InvalidatedSymbols &ConstIS, 1171 InvalidatedRegions *TopLevelRegions, 1172 InvalidatedRegions *TopLevelConstRegions, 1173 InvalidatedRegions *Invalidated) { 1174 GlobalsFilterKind GlobalsFilter; 1175 if (Call) { 1176 if (Call->isInSystemHeader()) 1177 GlobalsFilter = GFK_SystemOnly; 1178 else 1179 GlobalsFilter = GFK_All; 1180 } else { 1181 GlobalsFilter = GFK_None; 1182 } 1183 1184 RegionBindingsRef B = getRegionBindings(store); 1185 invalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, ConstIS, 1186 Invalidated, GlobalsFilter); 1187 1188 // Scan the bindings and generate the clusters. 1189 W.GenerateClusters(); 1190 1191 // Add the regions to the worklist. 1192 populateWorkList(W, Values, /*IsArrayOfConstRegions*/ false, 1193 TopLevelRegions); 1194 populateWorkList(W, ConstValues, /*IsArrayOfConstRegions*/ true, 1195 TopLevelConstRegions); 1196 1197 W.RunWorkList(); 1198 1199 // Return the new bindings. 1200 B = W.getRegionBindings(); 1201 1202 // For calls, determine which global regions should be invalidated and 1203 // invalidate them. (Note that function-static and immutable globals are never 1204 // invalidated by this.) 1205 // TODO: This could possibly be more precise with modules. 1206 switch (GlobalsFilter) { 1207 case GFK_All: 1208 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind, 1209 Ex, Count, LCtx, B, Invalidated); 1210 // FALLTHROUGH 1211 case GFK_SystemOnly: 1212 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1213 Ex, Count, LCtx, B, Invalidated); 1214 // FALLTHROUGH 1215 case GFK_None: 1216 break; 1217 } 1218 1219 return StoreRef(B.asStore(), *this); 1220} 1221 1222//===----------------------------------------------------------------------===// 1223// Extents for regions. 1224//===----------------------------------------------------------------------===// 1225 1226DefinedOrUnknownSVal 1227RegionStoreManager::getSizeInElements(ProgramStateRef state, 1228 const MemRegion *R, 1229 QualType EleTy) { 1230 SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder); 1231 const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size); 1232 if (!SizeInt) 1233 return UnknownVal(); 1234 1235 CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue()); 1236 1237 if (Ctx.getAsVariableArrayType(EleTy)) { 1238 // FIXME: We need to track extra state to properly record the size 1239 // of VLAs. Returning UnknownVal here, however, is a stop-gap so that 1240 // we don't have a divide-by-zero below. 1241 return UnknownVal(); 1242 } 1243 1244 CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy); 1245 1246 // If a variable is reinterpreted as a type that doesn't fit into a larger 1247 // type evenly, round it down. 1248 // This is a signed value, since it's used in arithmetic with signed indices. 1249 return svalBuilder.makeIntVal(RegionSize / EleSize, false); 1250} 1251 1252//===----------------------------------------------------------------------===// 1253// Location and region casting. 1254//===----------------------------------------------------------------------===// 1255 1256/// ArrayToPointer - Emulates the "decay" of an array to a pointer 1257/// type. 'Array' represents the lvalue of the array being decayed 1258/// to a pointer, and the returned SVal represents the decayed 1259/// version of that lvalue (i.e., a pointer to the first element of 1260/// the array). This is called by ExprEngine when evaluating casts 1261/// from arrays to pointers. 1262SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) { 1263 if (!Array.getAs<loc::MemRegionVal>()) 1264 return UnknownVal(); 1265 1266 const MemRegion* R = Array.castAs<loc::MemRegionVal>().getRegion(); 1267 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex(); 1268 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, R, Ctx)); 1269} 1270 1271//===----------------------------------------------------------------------===// 1272// Loading values from regions. 1273//===----------------------------------------------------------------------===// 1274 1275SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) { 1276 assert(!L.getAs<UnknownVal>() && "location unknown"); 1277 assert(!L.getAs<UndefinedVal>() && "location undefined"); 1278 1279 // For access to concrete addresses, return UnknownVal. Checks 1280 // for null dereferences (and similar errors) are done by checkers, not 1281 // the Store. 1282 // FIXME: We can consider lazily symbolicating such memory, but we really 1283 // should defer this when we can reason easily about symbolicating arrays 1284 // of bytes. 1285 if (L.getAs<loc::ConcreteInt>()) { 1286 return UnknownVal(); 1287 } 1288 if (!L.getAs<loc::MemRegionVal>()) { 1289 return UnknownVal(); 1290 } 1291 1292 const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion(); 1293 1294 if (isa<AllocaRegion>(MR) || 1295 isa<SymbolicRegion>(MR) || 1296 isa<CodeTextRegion>(MR)) { 1297 if (T.isNull()) { 1298 if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR)) 1299 T = TR->getLocationType(); 1300 else { 1301 const SymbolicRegion *SR = cast<SymbolicRegion>(MR); 1302 T = SR->getSymbol()->getType(); 1303 } 1304 } 1305 MR = GetElementZeroRegion(MR, T); 1306 } 1307 1308 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument 1309 // instead of 'Loc', and have the other Loc cases handled at a higher level. 1310 const TypedValueRegion *R = cast<TypedValueRegion>(MR); 1311 QualType RTy = R->getValueType(); 1312 1313 // FIXME: we do not yet model the parts of a complex type, so treat the 1314 // whole thing as "unknown". 1315 if (RTy->isAnyComplexType()) 1316 return UnknownVal(); 1317 1318 // FIXME: We should eventually handle funny addressing. e.g.: 1319 // 1320 // int x = ...; 1321 // int *p = &x; 1322 // char *q = (char*) p; 1323 // char c = *q; // returns the first byte of 'x'. 1324 // 1325 // Such funny addressing will occur due to layering of regions. 1326 if (RTy->isStructureOrClassType()) 1327 return getBindingForStruct(B, R); 1328 1329 // FIXME: Handle unions. 1330 if (RTy->isUnionType()) 1331 return UnknownVal(); 1332 1333 if (RTy->isArrayType()) { 1334 if (RTy->isConstantArrayType()) 1335 return getBindingForArray(B, R); 1336 else 1337 return UnknownVal(); 1338 } 1339 1340 // FIXME: handle Vector types. 1341 if (RTy->isVectorType()) 1342 return UnknownVal(); 1343 1344 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R)) 1345 return CastRetrievedVal(getBindingForField(B, FR), FR, T, false); 1346 1347 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) { 1348 // FIXME: Here we actually perform an implicit conversion from the loaded 1349 // value to the element type. Eventually we want to compose these values 1350 // more intelligently. For example, an 'element' can encompass multiple 1351 // bound regions (e.g., several bound bytes), or could be a subset of 1352 // a larger value. 1353 return CastRetrievedVal(getBindingForElement(B, ER), ER, T, false); 1354 } 1355 1356 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) { 1357 // FIXME: Here we actually perform an implicit conversion from the loaded 1358 // value to the ivar type. What we should model is stores to ivars 1359 // that blow past the extent of the ivar. If the address of the ivar is 1360 // reinterpretted, it is possible we stored a different value that could 1361 // fit within the ivar. Either we need to cast these when storing them 1362 // or reinterpret them lazily (as we do here). 1363 return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T, false); 1364 } 1365 1366 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { 1367 // FIXME: Here we actually perform an implicit conversion from the loaded 1368 // value to the variable type. What we should model is stores to variables 1369 // that blow past the extent of the variable. If the address of the 1370 // variable is reinterpretted, it is possible we stored a different value 1371 // that could fit within the variable. Either we need to cast these when 1372 // storing them or reinterpret them lazily (as we do here). 1373 return CastRetrievedVal(getBindingForVar(B, VR), VR, T, false); 1374 } 1375 1376 const SVal *V = B.lookup(R, BindingKey::Direct); 1377 1378 // Check if the region has a binding. 1379 if (V) 1380 return *V; 1381 1382 // The location does not have a bound value. This means that it has 1383 // the value it had upon its creation and/or entry to the analyzed 1384 // function/method. These are either symbolic values or 'undefined'. 1385 if (R->hasStackNonParametersStorage()) { 1386 // All stack variables are considered to have undefined values 1387 // upon creation. All heap allocated blocks are considered to 1388 // have undefined values as well unless they are explicitly bound 1389 // to specific values. 1390 return UndefinedVal(); 1391 } 1392 1393 // All other values are symbolic. 1394 return svalBuilder.getRegionValueSymbolVal(R); 1395} 1396 1397static QualType getUnderlyingType(const SubRegion *R) { 1398 QualType RegionTy; 1399 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) 1400 RegionTy = TVR->getValueType(); 1401 1402 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 1403 RegionTy = SR->getSymbol()->getType(); 1404 1405 return RegionTy; 1406} 1407 1408/// Checks to see if store \p B has a lazy binding for region \p R. 1409/// 1410/// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected 1411/// if there are additional bindings within \p R. 1412/// 1413/// Note that unlike RegionStoreManager::findLazyBinding, this will not search 1414/// for lazy bindings for super-regions of \p R. 1415static Optional<nonloc::LazyCompoundVal> 1416getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B, 1417 const SubRegion *R, bool AllowSubregionBindings) { 1418 Optional<SVal> V = B.getDefaultBinding(R); 1419 if (!V) 1420 return None; 1421 1422 Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>(); 1423 if (!LCV) 1424 return None; 1425 1426 // If the LCV is for a subregion, the types might not match, and we shouldn't 1427 // reuse the binding. 1428 QualType RegionTy = getUnderlyingType(R); 1429 if (!RegionTy.isNull() && 1430 !RegionTy->isVoidPointerType()) { 1431 QualType SourceRegionTy = LCV->getRegion()->getValueType(); 1432 if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy)) 1433 return None; 1434 } 1435 1436 if (!AllowSubregionBindings) { 1437 // If there are any other bindings within this region, we shouldn't reuse 1438 // the top-level binding. 1439 SmallVector<BindingPair, 16> Bindings; 1440 collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R, 1441 /*IncludeAllDefaultBindings=*/true); 1442 if (Bindings.size() > 1) 1443 return None; 1444 } 1445 1446 return *LCV; 1447} 1448 1449 1450std::pair<Store, const SubRegion *> 1451RegionStoreManager::findLazyBinding(RegionBindingsConstRef B, 1452 const SubRegion *R, 1453 const SubRegion *originalRegion) { 1454 if (originalRegion != R) { 1455 if (Optional<nonloc::LazyCompoundVal> V = 1456 getExistingLazyBinding(svalBuilder, B, R, true)) 1457 return std::make_pair(V->getStore(), V->getRegion()); 1458 } 1459 1460 typedef std::pair<Store, const SubRegion *> StoreRegionPair; 1461 StoreRegionPair Result = StoreRegionPair(); 1462 1463 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 1464 Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()), 1465 originalRegion); 1466 1467 if (Result.second) 1468 Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second); 1469 1470 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) { 1471 Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()), 1472 originalRegion); 1473 1474 if (Result.second) 1475 Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second); 1476 1477 } else if (const CXXBaseObjectRegion *BaseReg = 1478 dyn_cast<CXXBaseObjectRegion>(R)) { 1479 // C++ base object region is another kind of region that we should blast 1480 // through to look for lazy compound value. It is like a field region. 1481 Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()), 1482 originalRegion); 1483 1484 if (Result.second) 1485 Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg, 1486 Result.second); 1487 } 1488 1489 return Result; 1490} 1491 1492SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B, 1493 const ElementRegion* R) { 1494 // We do not currently model bindings of the CompoundLiteralregion. 1495 if (isa<CompoundLiteralRegion>(R->getBaseRegion())) 1496 return UnknownVal(); 1497 1498 // Check if the region has a binding. 1499 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1500 return *V; 1501 1502 const MemRegion* superR = R->getSuperRegion(); 1503 1504 // Check if the region is an element region of a string literal. 1505 if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) { 1506 // FIXME: Handle loads from strings where the literal is treated as 1507 // an integer, e.g., *((unsigned int*)"hello") 1508 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType(); 1509 if (!Ctx.hasSameUnqualifiedType(T, R->getElementType())) 1510 return UnknownVal(); 1511 1512 const StringLiteral *Str = StrR->getStringLiteral(); 1513 SVal Idx = R->getIndex(); 1514 if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) { 1515 int64_t i = CI->getValue().getSExtValue(); 1516 // Abort on string underrun. This can be possible by arbitrary 1517 // clients of getBindingForElement(). 1518 if (i < 0) 1519 return UndefinedVal(); 1520 int64_t length = Str->getLength(); 1521 // Technically, only i == length is guaranteed to be null. 1522 // However, such overflows should be caught before reaching this point; 1523 // the only time such an access would be made is if a string literal was 1524 // used to initialize a larger array. 1525 char c = (i >= length) ? '\0' : Str->getCodeUnit(i); 1526 return svalBuilder.makeIntVal(c, T); 1527 } 1528 } 1529 1530 // Check for loads from a code text region. For such loads, just give up. 1531 if (isa<CodeTextRegion>(superR)) 1532 return UnknownVal(); 1533 1534 // Handle the case where we are indexing into a larger scalar object. 1535 // For example, this handles: 1536 // int x = ... 1537 // char *y = &x; 1538 // return *y; 1539 // FIXME: This is a hack, and doesn't do anything really intelligent yet. 1540 const RegionRawOffset &O = R->getAsArrayOffset(); 1541 1542 // If we cannot reason about the offset, return an unknown value. 1543 if (!O.getRegion()) 1544 return UnknownVal(); 1545 1546 if (const TypedValueRegion *baseR = 1547 dyn_cast_or_null<TypedValueRegion>(O.getRegion())) { 1548 QualType baseT = baseR->getValueType(); 1549 if (baseT->isScalarType()) { 1550 QualType elemT = R->getElementType(); 1551 if (elemT->isScalarType()) { 1552 if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) { 1553 if (const Optional<SVal> &V = B.getDirectBinding(superR)) { 1554 if (SymbolRef parentSym = V->getAsSymbol()) 1555 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1556 1557 if (V->isUnknownOrUndef()) 1558 return *V; 1559 // Other cases: give up. We are indexing into a larger object 1560 // that has some value, but we don't know how to handle that yet. 1561 return UnknownVal(); 1562 } 1563 } 1564 } 1565 } 1566 } 1567 return getBindingForFieldOrElementCommon(B, R, R->getElementType()); 1568} 1569 1570SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B, 1571 const FieldRegion* R) { 1572 1573 // Check if the region has a binding. 1574 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1575 return *V; 1576 1577 QualType Ty = R->getValueType(); 1578 return getBindingForFieldOrElementCommon(B, R, Ty); 1579} 1580 1581Optional<SVal> 1582RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 1583 const MemRegion *superR, 1584 const TypedValueRegion *R, 1585 QualType Ty) { 1586 1587 if (const Optional<SVal> &D = B.getDefaultBinding(superR)) { 1588 const SVal &val = D.getValue(); 1589 if (SymbolRef parentSym = val.getAsSymbol()) 1590 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1591 1592 if (val.isZeroConstant()) 1593 return svalBuilder.makeZeroVal(Ty); 1594 1595 if (val.isUnknownOrUndef()) 1596 return val; 1597 1598 // Lazy bindings are usually handled through getExistingLazyBinding(). 1599 // We should unify these two code paths at some point. 1600 if (val.getAs<nonloc::LazyCompoundVal>()) 1601 return val; 1602 1603 llvm_unreachable("Unknown default value"); 1604 } 1605 1606 return None; 1607} 1608 1609SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion, 1610 RegionBindingsRef LazyBinding) { 1611 SVal Result; 1612 if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion)) 1613 Result = getBindingForElement(LazyBinding, ER); 1614 else 1615 Result = getBindingForField(LazyBinding, 1616 cast<FieldRegion>(LazyBindingRegion)); 1617 1618 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1619 // default value for /part/ of an aggregate from a default value for the 1620 // /entire/ aggregate. The most common case of this is when struct Outer 1621 // has as its first member a struct Inner, which is copied in from a stack 1622 // variable. In this case, even if the Outer's default value is symbolic, 0, 1623 // or unknown, it gets overridden by the Inner's default value of undefined. 1624 // 1625 // This is a general problem -- if the Inner is zero-initialized, the Outer 1626 // will now look zero-initialized. The proper way to solve this is with a 1627 // new version of RegionStore that tracks the extent of a binding as well 1628 // as the offset. 1629 // 1630 // This hack only takes care of the undefined case because that can very 1631 // quickly result in a warning. 1632 if (Result.isUndef()) 1633 Result = UnknownVal(); 1634 1635 return Result; 1636} 1637 1638SVal 1639RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 1640 const TypedValueRegion *R, 1641 QualType Ty) { 1642 1643 // At this point we have already checked in either getBindingForElement or 1644 // getBindingForField if 'R' has a direct binding. 1645 1646 // Lazy binding? 1647 Store lazyBindingStore = NULL; 1648 const SubRegion *lazyBindingRegion = NULL; 1649 llvm::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R); 1650 if (lazyBindingRegion) 1651 return getLazyBinding(lazyBindingRegion, 1652 getRegionBindings(lazyBindingStore)); 1653 1654 // Record whether or not we see a symbolic index. That can completely 1655 // be out of scope of our lookup. 1656 bool hasSymbolicIndex = false; 1657 1658 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1659 // default value for /part/ of an aggregate from a default value for the 1660 // /entire/ aggregate. The most common case of this is when struct Outer 1661 // has as its first member a struct Inner, which is copied in from a stack 1662 // variable. In this case, even if the Outer's default value is symbolic, 0, 1663 // or unknown, it gets overridden by the Inner's default value of undefined. 1664 // 1665 // This is a general problem -- if the Inner is zero-initialized, the Outer 1666 // will now look zero-initialized. The proper way to solve this is with a 1667 // new version of RegionStore that tracks the extent of a binding as well 1668 // as the offset. 1669 // 1670 // This hack only takes care of the undefined case because that can very 1671 // quickly result in a warning. 1672 bool hasPartialLazyBinding = false; 1673 1674 const SubRegion *SR = dyn_cast<SubRegion>(R); 1675 while (SR) { 1676 const MemRegion *Base = SR->getSuperRegion(); 1677 if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) { 1678 if (D->getAs<nonloc::LazyCompoundVal>()) { 1679 hasPartialLazyBinding = true; 1680 break; 1681 } 1682 1683 return *D; 1684 } 1685 1686 if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) { 1687 NonLoc index = ER->getIndex(); 1688 if (!index.isConstant()) 1689 hasSymbolicIndex = true; 1690 } 1691 1692 // If our super region is a field or element itself, walk up the region 1693 // hierarchy to see if there is a default value installed in an ancestor. 1694 SR = dyn_cast<SubRegion>(Base); 1695 } 1696 1697 if (R->hasStackNonParametersStorage()) { 1698 if (isa<ElementRegion>(R)) { 1699 // Currently we don't reason specially about Clang-style vectors. Check 1700 // if superR is a vector and if so return Unknown. 1701 if (const TypedValueRegion *typedSuperR = 1702 dyn_cast<TypedValueRegion>(R->getSuperRegion())) { 1703 if (typedSuperR->getValueType()->isVectorType()) 1704 return UnknownVal(); 1705 } 1706 } 1707 1708 // FIXME: We also need to take ElementRegions with symbolic indexes into 1709 // account. This case handles both directly accessing an ElementRegion 1710 // with a symbolic offset, but also fields within an element with 1711 // a symbolic offset. 1712 if (hasSymbolicIndex) 1713 return UnknownVal(); 1714 1715 if (!hasPartialLazyBinding) 1716 return UndefinedVal(); 1717 } 1718 1719 // All other values are symbolic. 1720 return svalBuilder.getRegionValueSymbolVal(R); 1721} 1722 1723SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B, 1724 const ObjCIvarRegion* R) { 1725 // Check if the region has a binding. 1726 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1727 return *V; 1728 1729 const MemRegion *superR = R->getSuperRegion(); 1730 1731 // Check if the super region has a default binding. 1732 if (const Optional<SVal> &V = B.getDefaultBinding(superR)) { 1733 if (SymbolRef parentSym = V->getAsSymbol()) 1734 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1735 1736 // Other cases: give up. 1737 return UnknownVal(); 1738 } 1739 1740 return getBindingForLazySymbol(R); 1741} 1742 1743SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B, 1744 const VarRegion *R) { 1745 1746 // Check if the region has a binding. 1747 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1748 return *V; 1749 1750 // Lazily derive a value for the VarRegion. 1751 const VarDecl *VD = R->getDecl(); 1752 const MemSpaceRegion *MS = R->getMemorySpace(); 1753 1754 // Arguments are always symbolic. 1755 if (isa<StackArgumentsSpaceRegion>(MS)) 1756 return svalBuilder.getRegionValueSymbolVal(R); 1757 1758 // Is 'VD' declared constant? If so, retrieve the constant value. 1759 if (VD->getType().isConstQualified()) 1760 if (const Expr *Init = VD->getInit()) 1761 if (Optional<SVal> V = svalBuilder.getConstantVal(Init)) 1762 return *V; 1763 1764 // This must come after the check for constants because closure-captured 1765 // constant variables may appear in UnknownSpaceRegion. 1766 if (isa<UnknownSpaceRegion>(MS)) 1767 return svalBuilder.getRegionValueSymbolVal(R); 1768 1769 if (isa<GlobalsSpaceRegion>(MS)) { 1770 QualType T = VD->getType(); 1771 1772 // Function-scoped static variables are default-initialized to 0; if they 1773 // have an initializer, it would have been processed by now. 1774 if (isa<StaticGlobalSpaceRegion>(MS)) 1775 return svalBuilder.makeZeroVal(T); 1776 1777 if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) { 1778 assert(!V->getAs<nonloc::LazyCompoundVal>()); 1779 return V.getValue(); 1780 } 1781 1782 return svalBuilder.getRegionValueSymbolVal(R); 1783 } 1784 1785 return UndefinedVal(); 1786} 1787 1788SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) { 1789 // All other values are symbolic. 1790 return svalBuilder.getRegionValueSymbolVal(R); 1791} 1792 1793const RegionStoreManager::SValListTy & 1794RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) { 1795 // First, check the cache. 1796 LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData()); 1797 if (I != LazyBindingsMap.end()) 1798 return I->second; 1799 1800 // If we don't have a list of values cached, start constructing it. 1801 SValListTy List; 1802 1803 const SubRegion *LazyR = LCV.getRegion(); 1804 RegionBindingsRef B = getRegionBindings(LCV.getStore()); 1805 1806 // If this region had /no/ bindings at the time, there are no interesting 1807 // values to return. 1808 const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion()); 1809 if (!Cluster) 1810 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1811 1812 SmallVector<BindingPair, 32> Bindings; 1813 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR, 1814 /*IncludeAllDefaultBindings=*/true); 1815 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 1816 E = Bindings.end(); 1817 I != E; ++I) { 1818 SVal V = I->second; 1819 if (V.isUnknownOrUndef() || V.isConstant()) 1820 continue; 1821 1822 if (Optional<nonloc::LazyCompoundVal> InnerLCV = 1823 V.getAs<nonloc::LazyCompoundVal>()) { 1824 const SValListTy &InnerList = getInterestingValues(*InnerLCV); 1825 List.insert(List.end(), InnerList.begin(), InnerList.end()); 1826 continue; 1827 } 1828 1829 List.push_back(V); 1830 } 1831 1832 return (LazyBindingsMap[LCV.getCVData()] = llvm_move(List)); 1833} 1834 1835NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B, 1836 const TypedValueRegion *R) { 1837 if (Optional<nonloc::LazyCompoundVal> V = 1838 getExistingLazyBinding(svalBuilder, B, R, false)) 1839 return *V; 1840 1841 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R); 1842} 1843 1844static bool isRecordEmpty(const RecordDecl *RD) { 1845 if (!RD->field_empty()) 1846 return false; 1847 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) 1848 return CRD->getNumBases() == 0; 1849 return true; 1850} 1851 1852SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B, 1853 const TypedValueRegion *R) { 1854 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl(); 1855 if (!RD->getDefinition() || isRecordEmpty(RD)) 1856 return UnknownVal(); 1857 1858 return createLazyBinding(B, R); 1859} 1860 1861SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B, 1862 const TypedValueRegion *R) { 1863 assert(Ctx.getAsConstantArrayType(R->getValueType()) && 1864 "Only constant array types can have compound bindings."); 1865 1866 return createLazyBinding(B, R); 1867} 1868 1869bool RegionStoreManager::includedInBindings(Store store, 1870 const MemRegion *region) const { 1871 RegionBindingsRef B = getRegionBindings(store); 1872 region = region->getBaseRegion(); 1873 1874 // Quick path: if the base is the head of a cluster, the region is live. 1875 if (B.lookup(region)) 1876 return true; 1877 1878 // Slow path: if the region is the VALUE of any binding, it is live. 1879 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) { 1880 const ClusterBindings &Cluster = RI.getData(); 1881 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1882 CI != CE; ++CI) { 1883 const SVal &D = CI.getData(); 1884 if (const MemRegion *R = D.getAsRegion()) 1885 if (R->getBaseRegion() == region) 1886 return true; 1887 } 1888 } 1889 1890 return false; 1891} 1892 1893//===----------------------------------------------------------------------===// 1894// Binding values to regions. 1895//===----------------------------------------------------------------------===// 1896 1897StoreRef RegionStoreManager::killBinding(Store ST, Loc L) { 1898 if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>()) 1899 if (const MemRegion* R = LV->getRegion()) 1900 return StoreRef(getRegionBindings(ST).removeBinding(R) 1901 .asImmutableMap() 1902 .getRootWithoutRetain(), 1903 *this); 1904 1905 return StoreRef(ST, *this); 1906} 1907 1908RegionBindingsRef 1909RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) { 1910 if (L.getAs<loc::ConcreteInt>()) 1911 return B; 1912 1913 // If we get here, the location should be a region. 1914 const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion(); 1915 1916 // Check if the region is a struct region. 1917 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) { 1918 QualType Ty = TR->getValueType(); 1919 if (Ty->isArrayType()) 1920 return bindArray(B, TR, V); 1921 if (Ty->isStructureOrClassType()) 1922 return bindStruct(B, TR, V); 1923 if (Ty->isVectorType()) 1924 return bindVector(B, TR, V); 1925 } 1926 1927 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 1928 // Binding directly to a symbolic region should be treated as binding 1929 // to element 0. 1930 QualType T = SR->getSymbol()->getType(); 1931 if (T->isAnyPointerType() || T->isReferenceType()) 1932 T = T->getPointeeType(); 1933 1934 R = GetElementZeroRegion(SR, T); 1935 } 1936 1937 // Clear out bindings that may overlap with this binding. 1938 RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R)); 1939 return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V); 1940} 1941 1942RegionBindingsRef 1943RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B, 1944 const MemRegion *R, 1945 QualType T) { 1946 SVal V; 1947 1948 if (Loc::isLocType(T)) 1949 V = svalBuilder.makeNull(); 1950 else if (T->isIntegralOrEnumerationType()) 1951 V = svalBuilder.makeZeroVal(T); 1952 else if (T->isStructureOrClassType() || T->isArrayType()) { 1953 // Set the default value to a zero constant when it is a structure 1954 // or array. The type doesn't really matter. 1955 V = svalBuilder.makeZeroVal(Ctx.IntTy); 1956 } 1957 else { 1958 // We can't represent values of this type, but we still need to set a value 1959 // to record that the region has been initialized. 1960 // If this assertion ever fires, a new case should be added above -- we 1961 // should know how to default-initialize any value we can symbolicate. 1962 assert(!SymbolManager::canSymbolicate(T) && "This type is representable"); 1963 V = UnknownVal(); 1964 } 1965 1966 return B.addBinding(R, BindingKey::Default, V); 1967} 1968 1969RegionBindingsRef 1970RegionStoreManager::bindArray(RegionBindingsConstRef B, 1971 const TypedValueRegion* R, 1972 SVal Init) { 1973 1974 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType())); 1975 QualType ElementTy = AT->getElementType(); 1976 Optional<uint64_t> Size; 1977 1978 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT)) 1979 Size = CAT->getSize().getZExtValue(); 1980 1981 // Check if the init expr is a string literal. 1982 if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) { 1983 const StringRegion *S = cast<StringRegion>(MRV->getRegion()); 1984 1985 // Treat the string as a lazy compound value. 1986 StoreRef store(B.asStore(), *this); 1987 nonloc::LazyCompoundVal LCV = svalBuilder.makeLazyCompoundVal(store, S) 1988 .castAs<nonloc::LazyCompoundVal>(); 1989 return bindAggregate(B, R, LCV); 1990 } 1991 1992 // Handle lazy compound values. 1993 if (Init.getAs<nonloc::LazyCompoundVal>()) 1994 return bindAggregate(B, R, Init); 1995 1996 // Remaining case: explicit compound values. 1997 1998 if (Init.isUnknown()) 1999 return setImplicitDefaultValue(B, R, ElementTy); 2000 2001 const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>(); 2002 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2003 uint64_t i = 0; 2004 2005 RegionBindingsRef NewB(B); 2006 2007 for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) { 2008 // The init list might be shorter than the array length. 2009 if (VI == VE) 2010 break; 2011 2012 const NonLoc &Idx = svalBuilder.makeArrayIndex(i); 2013 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx); 2014 2015 if (ElementTy->isStructureOrClassType()) 2016 NewB = bindStruct(NewB, ER, *VI); 2017 else if (ElementTy->isArrayType()) 2018 NewB = bindArray(NewB, ER, *VI); 2019 else 2020 NewB = bind(NewB, loc::MemRegionVal(ER), *VI); 2021 } 2022 2023 // If the init list is shorter than the array length, set the 2024 // array default value. 2025 if (Size.hasValue() && i < Size.getValue()) 2026 NewB = setImplicitDefaultValue(NewB, R, ElementTy); 2027 2028 return NewB; 2029} 2030 2031RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B, 2032 const TypedValueRegion* R, 2033 SVal V) { 2034 QualType T = R->getValueType(); 2035 assert(T->isVectorType()); 2036 const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs. 2037 2038 // Handle lazy compound values and symbolic values. 2039 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 2040 return bindAggregate(B, R, V); 2041 2042 // We may get non-CompoundVal accidentally due to imprecise cast logic or 2043 // that we are binding symbolic struct value. Kill the field values, and if 2044 // the value is symbolic go and bind it as a "default" binding. 2045 if (!V.getAs<nonloc::CompoundVal>()) { 2046 return bindAggregate(B, R, UnknownVal()); 2047 } 2048 2049 QualType ElemType = VT->getElementType(); 2050 nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>(); 2051 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2052 unsigned index = 0, numElements = VT->getNumElements(); 2053 RegionBindingsRef NewB(B); 2054 2055 for ( ; index != numElements ; ++index) { 2056 if (VI == VE) 2057 break; 2058 2059 NonLoc Idx = svalBuilder.makeArrayIndex(index); 2060 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx); 2061 2062 if (ElemType->isArrayType()) 2063 NewB = bindArray(NewB, ER, *VI); 2064 else if (ElemType->isStructureOrClassType()) 2065 NewB = bindStruct(NewB, ER, *VI); 2066 else 2067 NewB = bind(NewB, loc::MemRegionVal(ER), *VI); 2068 } 2069 return NewB; 2070} 2071 2072Optional<RegionBindingsRef> 2073RegionStoreManager::tryBindSmallStruct(RegionBindingsConstRef B, 2074 const TypedValueRegion *R, 2075 const RecordDecl *RD, 2076 nonloc::LazyCompoundVal LCV) { 2077 FieldVector Fields; 2078 2079 if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(RD)) 2080 if (Class->getNumBases() != 0 || Class->getNumVBases() != 0) 2081 return None; 2082 2083 for (RecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end(); 2084 I != E; ++I) { 2085 const FieldDecl *FD = *I; 2086 if (FD->isUnnamedBitfield()) 2087 continue; 2088 2089 // If there are too many fields, or if any of the fields are aggregates, 2090 // just use the LCV as a default binding. 2091 if (Fields.size() == SmallStructLimit) 2092 return None; 2093 2094 QualType Ty = FD->getType(); 2095 if (!(Ty->isScalarType() || Ty->isReferenceType())) 2096 return None; 2097 2098 Fields.push_back(*I); 2099 } 2100 2101 RegionBindingsRef NewB = B; 2102 2103 for (FieldVector::iterator I = Fields.begin(), E = Fields.end(); I != E; ++I){ 2104 const FieldRegion *SourceFR = MRMgr.getFieldRegion(*I, LCV.getRegion()); 2105 SVal V = getBindingForField(getRegionBindings(LCV.getStore()), SourceFR); 2106 2107 const FieldRegion *DestFR = MRMgr.getFieldRegion(*I, R); 2108 NewB = bind(NewB, loc::MemRegionVal(DestFR), V); 2109 } 2110 2111 return NewB; 2112} 2113 2114RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B, 2115 const TypedValueRegion* R, 2116 SVal V) { 2117 if (!Features.supportsFields()) 2118 return B; 2119 2120 QualType T = R->getValueType(); 2121 assert(T->isStructureOrClassType()); 2122 2123 const RecordType* RT = T->getAs<RecordType>(); 2124 const RecordDecl *RD = RT->getDecl(); 2125 2126 if (!RD->isCompleteDefinition()) 2127 return B; 2128 2129 // Handle lazy compound values and symbolic values. 2130 if (Optional<nonloc::LazyCompoundVal> LCV = 2131 V.getAs<nonloc::LazyCompoundVal>()) { 2132 if (Optional<RegionBindingsRef> NewB = tryBindSmallStruct(B, R, RD, *LCV)) 2133 return *NewB; 2134 return bindAggregate(B, R, V); 2135 } 2136 if (V.getAs<nonloc::SymbolVal>()) 2137 return bindAggregate(B, R, V); 2138 2139 // We may get non-CompoundVal accidentally due to imprecise cast logic or 2140 // that we are binding symbolic struct value. Kill the field values, and if 2141 // the value is symbolic go and bind it as a "default" binding. 2142 if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>()) 2143 return bindAggregate(B, R, UnknownVal()); 2144 2145 const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>(); 2146 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2147 2148 RecordDecl::field_iterator FI, FE; 2149 RegionBindingsRef NewB(B); 2150 2151 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) { 2152 2153 if (VI == VE) 2154 break; 2155 2156 // Skip any unnamed bitfields to stay in sync with the initializers. 2157 if (FI->isUnnamedBitfield()) 2158 continue; 2159 2160 QualType FTy = FI->getType(); 2161 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R); 2162 2163 if (FTy->isArrayType()) 2164 NewB = bindArray(NewB, FR, *VI); 2165 else if (FTy->isStructureOrClassType()) 2166 NewB = bindStruct(NewB, FR, *VI); 2167 else 2168 NewB = bind(NewB, loc::MemRegionVal(FR), *VI); 2169 ++VI; 2170 } 2171 2172 // There may be fewer values in the initialize list than the fields of struct. 2173 if (FI != FE) { 2174 NewB = NewB.addBinding(R, BindingKey::Default, 2175 svalBuilder.makeIntVal(0, false)); 2176 } 2177 2178 return NewB; 2179} 2180 2181RegionBindingsRef 2182RegionStoreManager::bindAggregate(RegionBindingsConstRef B, 2183 const TypedRegion *R, 2184 SVal Val) { 2185 // Remove the old bindings, using 'R' as the root of all regions 2186 // we will invalidate. Then add the new binding. 2187 return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val); 2188} 2189 2190//===----------------------------------------------------------------------===// 2191// State pruning. 2192//===----------------------------------------------------------------------===// 2193 2194namespace { 2195class removeDeadBindingsWorker : 2196 public ClusterAnalysis<removeDeadBindingsWorker> { 2197 SmallVector<const SymbolicRegion*, 12> Postponed; 2198 SymbolReaper &SymReaper; 2199 const StackFrameContext *CurrentLCtx; 2200 2201public: 2202 removeDeadBindingsWorker(RegionStoreManager &rm, 2203 ProgramStateManager &stateMgr, 2204 RegionBindingsRef b, SymbolReaper &symReaper, 2205 const StackFrameContext *LCtx) 2206 : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b, GFK_None), 2207 SymReaper(symReaper), CurrentLCtx(LCtx) {} 2208 2209 // Called by ClusterAnalysis. 2210 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C); 2211 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C); 2212 using ClusterAnalysis<removeDeadBindingsWorker>::VisitCluster; 2213 2214 bool UpdatePostponed(); 2215 void VisitBinding(SVal V); 2216}; 2217} 2218 2219void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR, 2220 const ClusterBindings &C) { 2221 2222 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) { 2223 if (SymReaper.isLive(VR)) 2224 AddToWorkList(baseR, &C); 2225 2226 return; 2227 } 2228 2229 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 2230 if (SymReaper.isLive(SR->getSymbol())) 2231 AddToWorkList(SR, &C); 2232 else 2233 Postponed.push_back(SR); 2234 2235 return; 2236 } 2237 2238 if (isa<NonStaticGlobalSpaceRegion>(baseR)) { 2239 AddToWorkList(baseR, &C); 2240 return; 2241 } 2242 2243 // CXXThisRegion in the current or parent location context is live. 2244 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) { 2245 const StackArgumentsSpaceRegion *StackReg = 2246 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion()); 2247 const StackFrameContext *RegCtx = StackReg->getStackFrame(); 2248 if (CurrentLCtx && 2249 (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))) 2250 AddToWorkList(TR, &C); 2251 } 2252} 2253 2254void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR, 2255 const ClusterBindings *C) { 2256 if (!C) 2257 return; 2258 2259 // Mark the symbol for any SymbolicRegion with live bindings as live itself. 2260 // This means we should continue to track that symbol. 2261 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR)) 2262 SymReaper.markLive(SymR->getSymbol()); 2263 2264 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) 2265 VisitBinding(I.getData()); 2266} 2267 2268void removeDeadBindingsWorker::VisitBinding(SVal V) { 2269 // Is it a LazyCompoundVal? All referenced regions are live as well. 2270 if (Optional<nonloc::LazyCompoundVal> LCS = 2271 V.getAs<nonloc::LazyCompoundVal>()) { 2272 2273 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 2274 2275 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 2276 E = Vals.end(); 2277 I != E; ++I) 2278 VisitBinding(*I); 2279 2280 return; 2281 } 2282 2283 // If V is a region, then add it to the worklist. 2284 if (const MemRegion *R = V.getAsRegion()) { 2285 AddToWorkList(R); 2286 2287 // All regions captured by a block are also live. 2288 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) { 2289 BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(), 2290 E = BR->referenced_vars_end(); 2291 for ( ; I != E; ++I) 2292 AddToWorkList(I.getCapturedRegion()); 2293 } 2294 } 2295 2296 2297 // Update the set of live symbols. 2298 for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end(); 2299 SI!=SE; ++SI) 2300 SymReaper.markLive(*SI); 2301} 2302 2303bool removeDeadBindingsWorker::UpdatePostponed() { 2304 // See if any postponed SymbolicRegions are actually live now, after 2305 // having done a scan. 2306 bool changed = false; 2307 2308 for (SmallVectorImpl<const SymbolicRegion*>::iterator 2309 I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) { 2310 if (const SymbolicRegion *SR = *I) { 2311 if (SymReaper.isLive(SR->getSymbol())) { 2312 changed |= AddToWorkList(SR); 2313 *I = NULL; 2314 } 2315 } 2316 } 2317 2318 return changed; 2319} 2320 2321StoreRef RegionStoreManager::removeDeadBindings(Store store, 2322 const StackFrameContext *LCtx, 2323 SymbolReaper& SymReaper) { 2324 RegionBindingsRef B = getRegionBindings(store); 2325 removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx); 2326 W.GenerateClusters(); 2327 2328 // Enqueue the region roots onto the worklist. 2329 for (SymbolReaper::region_iterator I = SymReaper.region_begin(), 2330 E = SymReaper.region_end(); I != E; ++I) { 2331 W.AddToWorkList(*I); 2332 } 2333 2334 do W.RunWorkList(); while (W.UpdatePostponed()); 2335 2336 // We have now scanned the store, marking reachable regions and symbols 2337 // as live. We now remove all the regions that are dead from the store 2338 // as well as update DSymbols with the set symbols that are now dead. 2339 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 2340 const MemRegion *Base = I.getKey(); 2341 2342 // If the cluster has been visited, we know the region has been marked. 2343 if (W.isVisited(Base)) 2344 continue; 2345 2346 // Remove the dead entry. 2347 B = B.remove(Base); 2348 2349 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base)) 2350 SymReaper.maybeDead(SymR->getSymbol()); 2351 2352 // Mark all non-live symbols that this binding references as dead. 2353 const ClusterBindings &Cluster = I.getData(); 2354 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 2355 CI != CE; ++CI) { 2356 SVal X = CI.getData(); 2357 SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end(); 2358 for (; SI != SE; ++SI) 2359 SymReaper.maybeDead(*SI); 2360 } 2361 } 2362 2363 return StoreRef(B.asStore(), *this); 2364} 2365 2366//===----------------------------------------------------------------------===// 2367// Utility methods. 2368//===----------------------------------------------------------------------===// 2369 2370void RegionStoreManager::print(Store store, raw_ostream &OS, 2371 const char* nl, const char *sep) { 2372 RegionBindingsRef B = getRegionBindings(store); 2373 OS << "Store (direct and default bindings), " 2374 << B.asStore() 2375 << " :" << nl; 2376 B.dump(OS, nl); 2377} 2378