RegionStore.cpp revision aa66b08d2d8bbf05bae8c68f58724f754ab57b35
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/CharUnits.h" 18#include "clang/Analysis/Analyses/LiveVariables.h" 19#include "clang/Analysis/AnalysisContext.h" 20#include "clang/Basic/TargetInfo.h" 21#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 22#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" 23#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 24#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 25#include "llvm/ADT/ImmutableList.h" 26#include "llvm/ADT/ImmutableMap.h" 27#include "llvm/ADT/Optional.h" 28#include "llvm/Support/raw_ostream.h" 29 30using namespace clang; 31using namespace ento; 32using llvm::Optional; 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 explicit BindingKey(const MemRegion *r, const MemRegion *Base, Kind k) 49 : P(r, k | Symbolic), Data(reinterpret_cast<uintptr_t>(Base)) { 50 assert(r && Base && "Must have known regions."); 51 assert(getConcreteOffsetRegion() == Base && "Failed to store base region"); 52 } 53 explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k) 54 : P(r, k), Data(offset) { 55 assert(r && "Must have known regions."); 56 assert(getOffset() == offset && "Failed to store offset"); 57 assert((r == r->getBaseRegion() || isa<ObjCIvarRegion>(r)) && "Not a base"); 58 } 59public: 60 61 bool isDirect() const { return P.getInt() & Direct; } 62 bool hasSymbolicOffset() const { return P.getInt() & Symbolic; } 63 64 const MemRegion *getRegion() const { return P.getPointer(); } 65 uint64_t getOffset() const { 66 assert(!hasSymbolicOffset()); 67 return Data; 68 } 69 70 const MemRegion *getConcreteOffsetRegion() const { 71 assert(hasSymbolicOffset()); 72 return reinterpret_cast<const MemRegion *>(static_cast<uintptr_t>(Data)); 73 } 74 75 const MemRegion *getBaseRegion() const { 76 if (hasSymbolicOffset()) 77 return getConcreteOffsetRegion()->getBaseRegion(); 78 return getRegion()->getBaseRegion(); 79 } 80 81 void Profile(llvm::FoldingSetNodeID& ID) const { 82 ID.AddPointer(P.getOpaqueValue()); 83 ID.AddInteger(Data); 84 } 85 86 static BindingKey Make(const MemRegion *R, Kind k); 87 88 bool operator<(const BindingKey &X) const { 89 if (P.getOpaqueValue() < X.P.getOpaqueValue()) 90 return true; 91 if (P.getOpaqueValue() > X.P.getOpaqueValue()) 92 return false; 93 return Data < X.Data; 94 } 95 96 bool operator==(const BindingKey &X) const { 97 return P.getOpaqueValue() == X.P.getOpaqueValue() && 98 Data == X.Data; 99 } 100 101 LLVM_ATTRIBUTE_USED void dump() const; 102}; 103} // end anonymous namespace 104 105BindingKey BindingKey::Make(const MemRegion *R, Kind k) { 106 const RegionOffset &RO = R->getAsOffset(); 107 if (RO.hasSymbolicOffset()) 108 return BindingKey(R, RO.getRegion(), k); 109 110 return BindingKey(RO.getRegion(), RO.getOffset(), k); 111} 112 113namespace llvm { 114 static inline 115 raw_ostream &operator<<(raw_ostream &os, BindingKey K) { 116 os << '(' << K.getRegion(); 117 if (!K.hasSymbolicOffset()) 118 os << ',' << K.getOffset(); 119 os << ',' << (K.isDirect() ? "direct" : "default") 120 << ')'; 121 return os; 122 } 123} // end llvm namespace 124 125void BindingKey::dump() const { 126 llvm::errs() << *this; 127} 128 129//===----------------------------------------------------------------------===// 130// Actual Store type. 131//===----------------------------------------------------------------------===// 132 133typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings; 134typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings> RegionBindings; 135 136//===----------------------------------------------------------------------===// 137// Fine-grained control of RegionStoreManager. 138//===----------------------------------------------------------------------===// 139 140namespace { 141struct minimal_features_tag {}; 142struct maximal_features_tag {}; 143 144class RegionStoreFeatures { 145 bool SupportsFields; 146public: 147 RegionStoreFeatures(minimal_features_tag) : 148 SupportsFields(false) {} 149 150 RegionStoreFeatures(maximal_features_tag) : 151 SupportsFields(true) {} 152 153 void enableFields(bool t) { SupportsFields = t; } 154 155 bool supportsFields() const { return SupportsFields; } 156}; 157} 158 159//===----------------------------------------------------------------------===// 160// Main RegionStore logic. 161//===----------------------------------------------------------------------===// 162 163namespace { 164 165class RegionStoreManager : public StoreManager { 166 const RegionStoreFeatures Features; 167 RegionBindings::Factory RBFactory; 168 ClusterBindings::Factory CBFactory; 169 170public: 171 RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f) 172 : StoreManager(mgr), Features(f), 173 RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()) {} 174 175 Optional<SVal> getDirectBinding(RegionBindings B, const MemRegion *R); 176 /// getDefaultBinding - Returns an SVal* representing an optional default 177 /// binding associated with a region and its subregions. 178 Optional<SVal> getDefaultBinding(RegionBindings B, const MemRegion *R); 179 180 /// setImplicitDefaultValue - Set the default binding for the provided 181 /// MemRegion to the value implicitly defined for compound literals when 182 /// the value is not specified. 183 StoreRef setImplicitDefaultValue(Store store, const MemRegion *R, QualType T); 184 185 /// ArrayToPointer - Emulates the "decay" of an array to a pointer 186 /// type. 'Array' represents the lvalue of the array being decayed 187 /// to a pointer, and the returned SVal represents the decayed 188 /// version of that lvalue (i.e., a pointer to the first element of 189 /// the array). This is called by ExprEngine when evaluating 190 /// casts from arrays to pointers. 191 SVal ArrayToPointer(Loc Array); 192 193 StoreRef getInitialStore(const LocationContext *InitLoc) { 194 return StoreRef(RBFactory.getEmptyMap().getRootWithoutRetain(), *this); 195 } 196 197 //===-------------------------------------------------------------------===// 198 // Binding values to regions. 199 //===-------------------------------------------------------------------===// 200 RegionBindings invalidateGlobalRegion(MemRegion::Kind K, 201 const Expr *Ex, 202 unsigned Count, 203 const LocationContext *LCtx, 204 RegionBindings B, 205 InvalidatedRegions *Invalidated); 206 207 StoreRef invalidateRegions(Store store, ArrayRef<const MemRegion *> Regions, 208 const Expr *E, unsigned Count, 209 const LocationContext *LCtx, 210 InvalidatedSymbols &IS, 211 const CallEvent *Call, 212 InvalidatedRegions *Invalidated); 213 214 bool scanReachableSymbols(Store S, const MemRegion *R, 215 ScanReachableSymbols &Callbacks); 216 217public: // Made public for helper classes. 218 219 RegionBindings removeSubRegionBindings(RegionBindings B, const SubRegion *R); 220 221 RegionBindings addBinding(RegionBindings B, BindingKey K, SVal V); 222 223 RegionBindings addBinding(RegionBindings B, const MemRegion *R, 224 BindingKey::Kind k, SVal V); 225 226 const SVal *lookup(RegionBindings B, BindingKey K); 227 const SVal *lookup(RegionBindings B, const MemRegion *R, BindingKey::Kind k); 228 229 RegionBindings removeBinding(RegionBindings B, BindingKey K); 230 RegionBindings removeBinding(RegionBindings B, const MemRegion *R, 231 BindingKey::Kind k); 232 233 RegionBindings removeBinding(RegionBindings B, const MemRegion *R) { 234 return removeBinding(removeBinding(B, R, BindingKey::Direct), R, 235 BindingKey::Default); 236 } 237 238 RegionBindings removeCluster(RegionBindings B, const MemRegion *R); 239 240public: // Part of public interface to class. 241 242 StoreRef Bind(Store store, Loc LV, SVal V); 243 244 // BindDefault is only used to initialize a region with a default value. 245 StoreRef BindDefault(Store store, const MemRegion *R, SVal V) { 246 RegionBindings B = GetRegionBindings(store); 247 assert(!lookup(B, R, BindingKey::Default)); 248 assert(!lookup(B, R, BindingKey::Direct)); 249 return StoreRef(addBinding(B, R, BindingKey::Default, V) 250 .getRootWithoutRetain(), *this); 251 } 252 253 /// \brief Create a new store that binds a value to a compound literal. 254 /// 255 /// \param ST The original store whose bindings are the basis for the new 256 /// store. 257 /// 258 /// \param CL The compound literal to bind (the binding key). 259 /// 260 /// \param LC The LocationContext for the binding. 261 /// 262 /// \param V The value to bind to the compound literal. 263 StoreRef bindCompoundLiteral(Store ST, 264 const CompoundLiteralExpr *CL, 265 const LocationContext *LC, SVal V); 266 267 /// BindStruct - Bind a compound value to a structure. 268 StoreRef BindStruct(Store store, const TypedValueRegion* R, SVal V); 269 270 /// BindVector - Bind a compound value to a vector. 271 StoreRef BindVector(Store store, const TypedValueRegion* R, SVal V); 272 273 StoreRef BindArray(Store store, const TypedValueRegion* R, SVal V); 274 275 /// Clears out all bindings in the given region and assigns a new value 276 /// as a Default binding. 277 StoreRef BindAggregate(Store store, const TypedRegion *R, SVal DefaultVal); 278 279 /// \brief Create a new store with the specified binding removed. 280 /// \param ST the original store, that is the basis for the new store. 281 /// \param L the location whose binding should be removed. 282 StoreRef killBinding(Store ST, Loc L); 283 284 void incrementReferenceCount(Store store) { 285 GetRegionBindings(store).manualRetain(); 286 } 287 288 /// If the StoreManager supports it, decrement the reference count of 289 /// the specified Store object. If the reference count hits 0, the memory 290 /// associated with the object is recycled. 291 void decrementReferenceCount(Store store) { 292 GetRegionBindings(store).manualRelease(); 293 } 294 295 bool includedInBindings(Store store, const MemRegion *region) const; 296 297 /// \brief Return the value bound to specified location in a given state. 298 /// 299 /// The high level logic for this method is this: 300 /// getBinding (L) 301 /// if L has binding 302 /// return L's binding 303 /// else if L is in killset 304 /// return unknown 305 /// else 306 /// if L is on stack or heap 307 /// return undefined 308 /// else 309 /// return symbolic 310 SVal getBinding(Store store, Loc L, QualType T = QualType()); 311 312 SVal getBindingForElement(Store store, const ElementRegion *R); 313 314 SVal getBindingForField(Store store, const FieldRegion *R); 315 316 SVal getBindingForObjCIvar(Store store, const ObjCIvarRegion *R); 317 318 SVal getBindingForVar(Store store, const VarRegion *R); 319 320 SVal getBindingForLazySymbol(const TypedValueRegion *R); 321 322 SVal getBindingForFieldOrElementCommon(Store store, const TypedValueRegion *R, 323 QualType Ty, const MemRegion *superR); 324 325 SVal getLazyBinding(const MemRegion *lazyBindingRegion, 326 Store lazyBindingStore); 327 328 /// Get bindings for the values in a struct and return a CompoundVal, used 329 /// when doing struct copy: 330 /// struct s x, y; 331 /// x = y; 332 /// y's value is retrieved by this method. 333 SVal getBindingForStruct(Store store, const TypedValueRegion* R); 334 335 SVal getBindingForArray(Store store, const TypedValueRegion* R); 336 337 /// Used to lazily generate derived symbols for bindings that are defined 338 /// implicitly by default bindings in a super region. 339 Optional<SVal> getBindingForDerivedDefaultValue(RegionBindings B, 340 const MemRegion *superR, 341 const TypedValueRegion *R, 342 QualType Ty); 343 344 /// Get the state and region whose binding this region R corresponds to. 345 std::pair<Store, const MemRegion*> 346 GetLazyBinding(RegionBindings B, const MemRegion *R, 347 const MemRegion *originalRegion, 348 bool includeSuffix = false); 349 350 //===------------------------------------------------------------------===// 351 // State pruning. 352 //===------------------------------------------------------------------===// 353 354 /// removeDeadBindings - Scans the RegionStore of 'state' for dead values. 355 /// It returns a new Store with these values removed. 356 StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, 357 SymbolReaper& SymReaper); 358 359 //===------------------------------------------------------------------===// 360 // Region "extents". 361 //===------------------------------------------------------------------===// 362 363 // FIXME: This method will soon be eliminated; see the note in Store.h. 364 DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state, 365 const MemRegion* R, QualType EleTy); 366 367 //===------------------------------------------------------------------===// 368 // Utility methods. 369 //===------------------------------------------------------------------===// 370 371 static inline RegionBindings GetRegionBindings(Store store) { 372 return RegionBindings(static_cast<const RegionBindings::TreeTy*>(store)); 373 } 374 375 void print(Store store, raw_ostream &Out, const char* nl, 376 const char *sep); 377 378 void iterBindings(Store store, BindingsHandler& f) { 379 RegionBindings B = GetRegionBindings(store); 380 for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 381 const ClusterBindings &Cluster = I.getData(); 382 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 383 CI != CE; ++CI) { 384 const BindingKey &K = CI.getKey(); 385 if (!K.isDirect()) 386 continue; 387 if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) { 388 // FIXME: Possibly incorporate the offset? 389 if (!f.HandleBinding(*this, store, R, CI.getData())) 390 return; 391 } 392 } 393 } 394 } 395}; 396 397} // end anonymous namespace 398 399//===----------------------------------------------------------------------===// 400// RegionStore creation. 401//===----------------------------------------------------------------------===// 402 403StoreManager *ento::CreateRegionStoreManager(ProgramStateManager& StMgr) { 404 RegionStoreFeatures F = maximal_features_tag(); 405 return new RegionStoreManager(StMgr, F); 406} 407 408StoreManager * 409ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) { 410 RegionStoreFeatures F = minimal_features_tag(); 411 F.enableFields(true); 412 return new RegionStoreManager(StMgr, F); 413} 414 415 416//===----------------------------------------------------------------------===// 417// Region Cluster analysis. 418//===----------------------------------------------------------------------===// 419 420namespace { 421template <typename DERIVED> 422class ClusterAnalysis { 423protected: 424 typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap; 425 typedef SmallVector<const MemRegion *, 10> WorkList; 426 427 llvm::SmallPtrSet<const ClusterBindings *, 16> Visited; 428 429 WorkList WL; 430 431 RegionStoreManager &RM; 432 ASTContext &Ctx; 433 SValBuilder &svalBuilder; 434 435 RegionBindings B; 436 437 const bool includeGlobals; 438 439 const ClusterBindings *getCluster(const MemRegion *R) { 440 return B.lookup(R); 441 } 442 443public: 444 ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr, 445 RegionBindings b, const bool includeGlobals) 446 : RM(rm), Ctx(StateMgr.getContext()), 447 svalBuilder(StateMgr.getSValBuilder()), 448 B(b), includeGlobals(includeGlobals) {} 449 450 RegionBindings getRegionBindings() const { return B; } 451 452 bool isVisited(const MemRegion *R) { 453 return Visited.count(getCluster(R)); 454 } 455 456 void GenerateClusters() { 457 // Scan the entire set of bindings and record the region clusters. 458 for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){ 459 const MemRegion *Base = RI.getKey(); 460 461 const ClusterBindings &Cluster = RI.getData(); 462 assert(!Cluster.isEmpty() && "Empty clusters should be removed"); 463 static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster); 464 465 if (includeGlobals) 466 if (isa<NonStaticGlobalSpaceRegion>(Base->getMemorySpace())) 467 AddToWorkList(Base, &Cluster); 468 } 469 } 470 471 bool AddToWorkList(const MemRegion *R, const ClusterBindings *C) { 472 if (C && !Visited.insert(C)) 473 return false; 474 WL.push_back(R); 475 return true; 476 } 477 478 bool AddToWorkList(const MemRegion *R) { 479 const MemRegion *baseR = R->getBaseRegion(); 480 return AddToWorkList(baseR, getCluster(baseR)); 481 } 482 483 void RunWorkList() { 484 while (!WL.empty()) { 485 const MemRegion *baseR = WL.pop_back_val(); 486 487 // First visit the cluster. 488 if (const ClusterBindings *Cluster = getCluster(baseR)) 489 static_cast<DERIVED*>(this)->VisitCluster(baseR, *Cluster); 490 491 // Next, visit the base region. 492 static_cast<DERIVED*>(this)->VisitBaseRegion(baseR); 493 } 494 } 495 496public: 497 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {} 498 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C) {} 499 void VisitBaseRegion(const MemRegion *baseR) {} 500}; 501} 502 503//===----------------------------------------------------------------------===// 504// Binding invalidation. 505//===----------------------------------------------------------------------===// 506 507bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R, 508 ScanReachableSymbols &Callbacks) { 509 assert(R == R->getBaseRegion() && "Should only be called for base regions"); 510 RegionBindings B = GetRegionBindings(S); 511 const ClusterBindings *Cluster = B.lookup(R); 512 513 if (!Cluster) 514 return true; 515 516 for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end(); 517 RI != RE; ++RI) { 518 if (!Callbacks.scan(RI.getData())) 519 return false; 520 } 521 522 return true; 523} 524 525RegionBindings RegionStoreManager::removeSubRegionBindings(RegionBindings B, 526 const SubRegion *R) { 527 BindingKey SRKey = BindingKey::Make(R, BindingKey::Default); 528 const MemRegion *ClusterHead = SRKey.getBaseRegion(); 529 if (R == ClusterHead) { 530 // We can remove an entire cluster's bindings all in one go. 531 return RBFactory.remove(B, R); 532 } 533 534 if (SRKey.hasSymbolicOffset()) { 535 const SubRegion *Base = cast<SubRegion>(SRKey.getConcreteOffsetRegion()); 536 B = removeSubRegionBindings(B, Base); 537 return addBinding(B, Base, BindingKey::Default, UnknownVal()); 538 } 539 540 // This assumes the region being invalidated is char-aligned. This isn't 541 // true for bitfields, but since bitfields have no subregions they shouldn't 542 // be using this function anyway. 543 uint64_t Length = UINT64_MAX; 544 545 SVal Extent = R->getExtent(svalBuilder); 546 if (nonloc::ConcreteInt *ExtentCI = dyn_cast<nonloc::ConcreteInt>(&Extent)) { 547 const llvm::APSInt &ExtentInt = ExtentCI->getValue(); 548 assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned()); 549 // Extents are in bytes but region offsets are in bits. Be careful! 550 Length = ExtentInt.getLimitedValue() * Ctx.getCharWidth(); 551 } 552 553 const ClusterBindings *Cluster = B.lookup(ClusterHead); 554 if (!Cluster) 555 return B; 556 557 ClusterBindings Result = *Cluster; 558 559 // It is safe to iterate over the bindings as they are being changed 560 // because they are in an ImmutableMap. 561 for (ClusterBindings::iterator I = Cluster->begin(), E = Cluster->end(); 562 I != E; ++I) { 563 BindingKey NextKey = I.getKey(); 564 if (NextKey.getRegion() == SRKey.getRegion()) { 565 if (NextKey.getOffset() > SRKey.getOffset() && 566 NextKey.getOffset() - SRKey.getOffset() < Length) { 567 // Case 1: The next binding is inside the region we're invalidating. 568 // Remove it. 569 Result = CBFactory.remove(Result, NextKey); 570 } else if (NextKey.getOffset() == SRKey.getOffset()) { 571 // Case 2: The next binding is at the same offset as the region we're 572 // invalidating. In this case, we need to leave default bindings alone, 573 // since they may be providing a default value for a regions beyond what 574 // we're invalidating. 575 // FIXME: This is probably incorrect; consider invalidating an outer 576 // struct whose first field is bound to a LazyCompoundVal. 577 if (NextKey.isDirect()) 578 Result = CBFactory.remove(Result, NextKey); 579 } 580 } else if (NextKey.hasSymbolicOffset()) { 581 const MemRegion *Base = NextKey.getConcreteOffsetRegion(); 582 if (R->isSubRegionOf(Base)) { 583 // Case 3: The next key is symbolic and we just changed something within 584 // its concrete region. We don't know if the binding is still valid, so 585 // we'll be conservative and remove it. 586 if (NextKey.isDirect()) 587 Result = CBFactory.remove(Result, NextKey); 588 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) { 589 // Case 4: The next key is symbolic, but we changed a known 590 // super-region. In this case the binding is certainly no longer valid. 591 if (R == Base || BaseSR->isSubRegionOf(R)) 592 Result = CBFactory.remove(Result, NextKey); 593 } 594 } 595 } 596 597 if (Result.isEmpty()) 598 return RBFactory.remove(B, ClusterHead); 599 return RBFactory.add(B, ClusterHead, Result); 600} 601 602namespace { 603class invalidateRegionsWorker : public ClusterAnalysis<invalidateRegionsWorker> 604{ 605 const Expr *Ex; 606 unsigned Count; 607 const LocationContext *LCtx; 608 StoreManager::InvalidatedSymbols &IS; 609 StoreManager::InvalidatedRegions *Regions; 610public: 611 invalidateRegionsWorker(RegionStoreManager &rm, 612 ProgramStateManager &stateMgr, 613 RegionBindings b, 614 const Expr *ex, unsigned count, 615 const LocationContext *lctx, 616 StoreManager::InvalidatedSymbols &is, 617 StoreManager::InvalidatedRegions *r, 618 bool includeGlobals) 619 : ClusterAnalysis<invalidateRegionsWorker>(rm, stateMgr, b, includeGlobals), 620 Ex(ex), Count(count), LCtx(lctx), IS(is), Regions(r) {} 621 622 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C); 623 void VisitBaseRegion(const MemRegion *baseR); 624 625private: 626 void VisitBinding(SVal V); 627}; 628} 629 630void invalidateRegionsWorker::VisitBinding(SVal V) { 631 // A symbol? Mark it touched by the invalidation. 632 if (SymbolRef Sym = V.getAsSymbol()) 633 IS.insert(Sym); 634 635 if (const MemRegion *R = V.getAsRegion()) { 636 AddToWorkList(R); 637 return; 638 } 639 640 // Is it a LazyCompoundVal? All references get invalidated as well. 641 if (const nonloc::LazyCompoundVal *LCS = 642 dyn_cast<nonloc::LazyCompoundVal>(&V)) { 643 644 const MemRegion *LazyR = LCS->getRegion(); 645 RegionBindings B = RegionStoreManager::GetRegionBindings(LCS->getStore()); 646 647 // FIXME: This should not have to walk all bindings in the old store. 648 for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){ 649 const ClusterBindings &Cluster = RI.getData(); 650 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 651 CI != CE; ++CI) { 652 BindingKey K = CI.getKey(); 653 if (const SubRegion *BaseR = dyn_cast<SubRegion>(K.getRegion())) { 654 if (BaseR == LazyR) 655 VisitBinding(CI.getData()); 656 else if (K.hasSymbolicOffset() && BaseR->isSubRegionOf(LazyR)) 657 VisitBinding(CI.getData()); 658 } 659 } 660 } 661 662 return; 663 } 664} 665 666void invalidateRegionsWorker::VisitCluster(const MemRegion *BaseR, 667 const ClusterBindings &C) { 668 for (ClusterBindings::iterator I = C.begin(), E = C.end(); I != E; ++I) 669 VisitBinding(I.getData()); 670 671 B = RM.removeCluster(B, BaseR); 672} 673 674void invalidateRegionsWorker::VisitBaseRegion(const MemRegion *baseR) { 675 // Symbolic region? Mark that symbol touched by the invalidation. 676 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) 677 IS.insert(SR->getSymbol()); 678 679 // BlockDataRegion? If so, invalidate captured variables that are passed 680 // by reference. 681 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) { 682 for (BlockDataRegion::referenced_vars_iterator 683 BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ; 684 BI != BE; ++BI) { 685 const VarRegion *VR = *BI; 686 const VarDecl *VD = VR->getDecl(); 687 if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage()) { 688 AddToWorkList(VR); 689 } 690 else if (Loc::isLocType(VR->getValueType())) { 691 // Map the current bindings to a Store to retrieve the value 692 // of the binding. If that binding itself is a region, we should 693 // invalidate that region. This is because a block may capture 694 // a pointer value, but the thing pointed by that pointer may 695 // get invalidated. 696 Store store = B.getRootWithoutRetain(); 697 SVal V = RM.getBinding(store, loc::MemRegionVal(VR)); 698 if (const Loc *L = dyn_cast<Loc>(&V)) { 699 if (const MemRegion *LR = L->getAsRegion()) 700 AddToWorkList(LR); 701 } 702 } 703 } 704 return; 705 } 706 707 // Otherwise, we have a normal data region. Record that we touched the region. 708 if (Regions) 709 Regions->push_back(baseR); 710 711 if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) { 712 // Invalidate the region by setting its default value to 713 // conjured symbol. The type of the symbol is irrelavant. 714 DefinedOrUnknownSVal V = 715 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count); 716 B = RM.addBinding(B, baseR, BindingKey::Default, V); 717 return; 718 } 719 720 if (!baseR->isBoundable()) 721 return; 722 723 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR); 724 QualType T = TR->getValueType(); 725 726 // Invalidate the binding. 727 if (T->isStructureOrClassType()) { 728 // Invalidate the region by setting its default value to 729 // conjured symbol. The type of the symbol is irrelavant. 730 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 731 Ctx.IntTy, Count); 732 B = RM.addBinding(B, baseR, BindingKey::Default, V); 733 return; 734 } 735 736 if (const ArrayType *AT = Ctx.getAsArrayType(T)) { 737 // Set the default value of the array to conjured symbol. 738 DefinedOrUnknownSVal V = 739 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 740 AT->getElementType(), Count); 741 B = RM.addBinding(B, baseR, BindingKey::Default, V); 742 return; 743 } 744 745 if (includeGlobals && 746 isa<NonStaticGlobalSpaceRegion>(baseR->getMemorySpace())) { 747 // If the region is a global and we are invalidating all globals, 748 // just erase the entry. This causes all globals to be lazily 749 // symbolicated from the same base symbol. 750 B = RM.removeBinding(B, baseR); 751 return; 752 } 753 754 755 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 756 T,Count); 757 assert(SymbolManager::canSymbolicate(T) || V.isUnknown()); 758 B = RM.addBinding(B, baseR, BindingKey::Direct, V); 759} 760 761RegionBindings RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K, 762 const Expr *Ex, 763 unsigned Count, 764 const LocationContext *LCtx, 765 RegionBindings B, 766 InvalidatedRegions *Invalidated) { 767 // Bind the globals memory space to a new symbol that we will use to derive 768 // the bindings for all globals. 769 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K); 770 SVal V = svalBuilder.conjureSymbolVal(/* SymbolTag = */ (const void*) GS, Ex, LCtx, 771 /* type does not matter */ Ctx.IntTy, 772 Count); 773 774 B = removeBinding(B, GS); 775 B = addBinding(B, BindingKey::Make(GS, BindingKey::Default), V); 776 777 // Even if there are no bindings in the global scope, we still need to 778 // record that we touched it. 779 if (Invalidated) 780 Invalidated->push_back(GS); 781 782 return B; 783} 784 785StoreRef RegionStoreManager::invalidateRegions(Store store, 786 ArrayRef<const MemRegion *> Regions, 787 const Expr *Ex, unsigned Count, 788 const LocationContext *LCtx, 789 InvalidatedSymbols &IS, 790 const CallEvent *Call, 791 InvalidatedRegions *Invalidated) { 792 invalidateRegionsWorker W(*this, StateMgr, 793 RegionStoreManager::GetRegionBindings(store), 794 Ex, Count, LCtx, IS, Invalidated, false); 795 796 // Scan the bindings and generate the clusters. 797 W.GenerateClusters(); 798 799 // Add the regions to the worklist. 800 for (ArrayRef<const MemRegion *>::iterator 801 I = Regions.begin(), E = Regions.end(); I != E; ++I) 802 W.AddToWorkList(*I); 803 804 W.RunWorkList(); 805 806 // Return the new bindings. 807 RegionBindings B = W.getRegionBindings(); 808 809 // For all globals which are not static nor immutable: determine which global 810 // regions should be invalidated and invalidate them. 811 // TODO: This could possibly be more precise with modules. 812 // 813 // System calls invalidate only system globals. 814 if (Call && Call->isInSystemHeader()) { 815 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 816 Ex, Count, LCtx, B, Invalidated); 817 // Internal calls might invalidate both system and internal globals. 818 } else { 819 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 820 Ex, Count, LCtx, B, Invalidated); 821 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind, 822 Ex, Count, LCtx, B, Invalidated); 823 } 824 825 return StoreRef(B.getRootWithoutRetain(), *this); 826} 827 828//===----------------------------------------------------------------------===// 829// Extents for regions. 830//===----------------------------------------------------------------------===// 831 832DefinedOrUnknownSVal 833RegionStoreManager::getSizeInElements(ProgramStateRef state, 834 const MemRegion *R, 835 QualType EleTy) { 836 SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder); 837 const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size); 838 if (!SizeInt) 839 return UnknownVal(); 840 841 CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue()); 842 843 if (Ctx.getAsVariableArrayType(EleTy)) { 844 // FIXME: We need to track extra state to properly record the size 845 // of VLAs. Returning UnknownVal here, however, is a stop-gap so that 846 // we don't have a divide-by-zero below. 847 return UnknownVal(); 848 } 849 850 CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy); 851 852 // If a variable is reinterpreted as a type that doesn't fit into a larger 853 // type evenly, round it down. 854 // This is a signed value, since it's used in arithmetic with signed indices. 855 return svalBuilder.makeIntVal(RegionSize / EleSize, false); 856} 857 858//===----------------------------------------------------------------------===// 859// Location and region casting. 860//===----------------------------------------------------------------------===// 861 862/// ArrayToPointer - Emulates the "decay" of an array to a pointer 863/// type. 'Array' represents the lvalue of the array being decayed 864/// to a pointer, and the returned SVal represents the decayed 865/// version of that lvalue (i.e., a pointer to the first element of 866/// the array). This is called by ExprEngine when evaluating casts 867/// from arrays to pointers. 868SVal RegionStoreManager::ArrayToPointer(Loc Array) { 869 if (!isa<loc::MemRegionVal>(Array)) 870 return UnknownVal(); 871 872 const MemRegion* R = cast<loc::MemRegionVal>(&Array)->getRegion(); 873 const TypedValueRegion* ArrayR = dyn_cast<TypedValueRegion>(R); 874 875 if (!ArrayR) 876 return UnknownVal(); 877 878 // Strip off typedefs from the ArrayRegion's ValueType. 879 QualType T = ArrayR->getValueType().getDesugaredType(Ctx); 880 const ArrayType *AT = cast<ArrayType>(T); 881 T = AT->getElementType(); 882 883 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex(); 884 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, ArrayR, Ctx)); 885} 886 887//===----------------------------------------------------------------------===// 888// Loading values from regions. 889//===----------------------------------------------------------------------===// 890 891Optional<SVal> RegionStoreManager::getDirectBinding(RegionBindings B, 892 const MemRegion *R) { 893 894 if (const SVal *V = lookup(B, R, BindingKey::Direct)) 895 return *V; 896 897 return Optional<SVal>(); 898} 899 900Optional<SVal> RegionStoreManager::getDefaultBinding(RegionBindings B, 901 const MemRegion *R) { 902 if (R->isBoundable()) 903 if (const TypedValueRegion *TR = dyn_cast<TypedValueRegion>(R)) 904 if (TR->getValueType()->isUnionType()) 905 return UnknownVal(); 906 907 if (const SVal *V = lookup(B, R, BindingKey::Default)) 908 return *V; 909 910 return Optional<SVal>(); 911} 912 913SVal RegionStoreManager::getBinding(Store store, Loc L, QualType T) { 914 assert(!isa<UnknownVal>(L) && "location unknown"); 915 assert(!isa<UndefinedVal>(L) && "location undefined"); 916 917 // For access to concrete addresses, return UnknownVal. Checks 918 // for null dereferences (and similar errors) are done by checkers, not 919 // the Store. 920 // FIXME: We can consider lazily symbolicating such memory, but we really 921 // should defer this when we can reason easily about symbolicating arrays 922 // of bytes. 923 if (isa<loc::ConcreteInt>(L)) { 924 return UnknownVal(); 925 } 926 if (!isa<loc::MemRegionVal>(L)) { 927 return UnknownVal(); 928 } 929 930 const MemRegion *MR = cast<loc::MemRegionVal>(L).getRegion(); 931 932 if (isa<AllocaRegion>(MR) || 933 isa<SymbolicRegion>(MR) || 934 isa<CodeTextRegion>(MR)) { 935 if (T.isNull()) { 936 if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR)) 937 T = TR->getLocationType(); 938 else { 939 const SymbolicRegion *SR = cast<SymbolicRegion>(MR); 940 T = SR->getSymbol()->getType(); 941 } 942 } 943 MR = GetElementZeroRegion(MR, T); 944 } 945 946 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument 947 // instead of 'Loc', and have the other Loc cases handled at a higher level. 948 const TypedValueRegion *R = cast<TypedValueRegion>(MR); 949 QualType RTy = R->getValueType(); 950 951 // FIXME: We should eventually handle funny addressing. e.g.: 952 // 953 // int x = ...; 954 // int *p = &x; 955 // char *q = (char*) p; 956 // char c = *q; // returns the first byte of 'x'. 957 // 958 // Such funny addressing will occur due to layering of regions. 959 960 if (RTy->isStructureOrClassType()) 961 return getBindingForStruct(store, R); 962 963 // FIXME: Handle unions. 964 if (RTy->isUnionType()) 965 return UnknownVal(); 966 967 if (RTy->isArrayType()) { 968 if (RTy->isConstantArrayType()) 969 return getBindingForArray(store, R); 970 else 971 return UnknownVal(); 972 } 973 974 // FIXME: handle Vector types. 975 if (RTy->isVectorType()) 976 return UnknownVal(); 977 978 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R)) 979 return CastRetrievedVal(getBindingForField(store, FR), FR, T, false); 980 981 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) { 982 // FIXME: Here we actually perform an implicit conversion from the loaded 983 // value to the element type. Eventually we want to compose these values 984 // more intelligently. For example, an 'element' can encompass multiple 985 // bound regions (e.g., several bound bytes), or could be a subset of 986 // a larger value. 987 return CastRetrievedVal(getBindingForElement(store, ER), ER, T, false); 988 } 989 990 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) { 991 // FIXME: Here we actually perform an implicit conversion from the loaded 992 // value to the ivar type. What we should model is stores to ivars 993 // that blow past the extent of the ivar. If the address of the ivar is 994 // reinterpretted, it is possible we stored a different value that could 995 // fit within the ivar. Either we need to cast these when storing them 996 // or reinterpret them lazily (as we do here). 997 return CastRetrievedVal(getBindingForObjCIvar(store, IVR), IVR, T, false); 998 } 999 1000 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { 1001 // FIXME: Here we actually perform an implicit conversion from the loaded 1002 // value to the variable type. What we should model is stores to variables 1003 // that blow past the extent of the variable. If the address of the 1004 // variable is reinterpretted, it is possible we stored a different value 1005 // that could fit within the variable. Either we need to cast these when 1006 // storing them or reinterpret them lazily (as we do here). 1007 return CastRetrievedVal(getBindingForVar(store, VR), VR, T, false); 1008 } 1009 1010 RegionBindings B = GetRegionBindings(store); 1011 const SVal *V = lookup(B, R, BindingKey::Direct); 1012 1013 // Check if the region has a binding. 1014 if (V) 1015 return *V; 1016 1017 // The location does not have a bound value. This means that it has 1018 // the value it had upon its creation and/or entry to the analyzed 1019 // function/method. These are either symbolic values or 'undefined'. 1020 if (R->hasStackNonParametersStorage()) { 1021 // All stack variables are considered to have undefined values 1022 // upon creation. All heap allocated blocks are considered to 1023 // have undefined values as well unless they are explicitly bound 1024 // to specific values. 1025 return UndefinedVal(); 1026 } 1027 1028 // All other values are symbolic. 1029 return svalBuilder.getRegionValueSymbolVal(R); 1030} 1031 1032std::pair<Store, const MemRegion *> 1033RegionStoreManager::GetLazyBinding(RegionBindings B, const MemRegion *R, 1034 const MemRegion *originalRegion, 1035 bool includeSuffix) { 1036 1037 if (originalRegion != R) { 1038 if (Optional<SVal> OV = getDefaultBinding(B, R)) { 1039 if (const nonloc::LazyCompoundVal *V = 1040 dyn_cast<nonloc::LazyCompoundVal>(OV.getPointer())) 1041 return std::make_pair(V->getStore(), V->getRegion()); 1042 } 1043 } 1044 1045 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 1046 const std::pair<Store, const MemRegion *> &X = 1047 GetLazyBinding(B, ER->getSuperRegion(), originalRegion); 1048 1049 if (X.second) 1050 return std::make_pair(X.first, 1051 MRMgr.getElementRegionWithSuper(ER, X.second)); 1052 } 1053 else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) { 1054 const std::pair<Store, const MemRegion *> &X = 1055 GetLazyBinding(B, FR->getSuperRegion(), originalRegion); 1056 1057 if (X.second) { 1058 if (includeSuffix) 1059 return std::make_pair(X.first, 1060 MRMgr.getFieldRegionWithSuper(FR, X.second)); 1061 return X; 1062 } 1063 1064 } 1065 // C++ base object region is another kind of region that we should blast 1066 // through to look for lazy compound value. It is like a field region. 1067 else if (const CXXBaseObjectRegion *baseReg = 1068 dyn_cast<CXXBaseObjectRegion>(R)) { 1069 const std::pair<Store, const MemRegion *> &X = 1070 GetLazyBinding(B, baseReg->getSuperRegion(), originalRegion); 1071 1072 if (X.second) { 1073 if (includeSuffix) 1074 return std::make_pair(X.first, 1075 MRMgr.getCXXBaseObjectRegionWithSuper(baseReg, 1076 X.second)); 1077 return X; 1078 } 1079 } 1080 1081 // The NULL MemRegion indicates an non-existent lazy binding. A NULL Store is 1082 // possible for a valid lazy binding. 1083 return std::make_pair((Store) 0, (const MemRegion *) 0); 1084} 1085 1086SVal RegionStoreManager::getBindingForElement(Store store, 1087 const ElementRegion* R) { 1088 // We do not currently model bindings of the CompoundLiteralregion. 1089 if (isa<CompoundLiteralRegion>(R->getBaseRegion())) 1090 return UnknownVal(); 1091 1092 // Check if the region has a binding. 1093 RegionBindings B = GetRegionBindings(store); 1094 if (const Optional<SVal> &V = getDirectBinding(B, R)) 1095 return *V; 1096 1097 const MemRegion* superR = R->getSuperRegion(); 1098 1099 // Check if the region is an element region of a string literal. 1100 if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) { 1101 // FIXME: Handle loads from strings where the literal is treated as 1102 // an integer, e.g., *((unsigned int*)"hello") 1103 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType(); 1104 if (T != Ctx.getCanonicalType(R->getElementType())) 1105 return UnknownVal(); 1106 1107 const StringLiteral *Str = StrR->getStringLiteral(); 1108 SVal Idx = R->getIndex(); 1109 if (nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(&Idx)) { 1110 int64_t i = CI->getValue().getSExtValue(); 1111 // Abort on string underrun. This can be possible by arbitrary 1112 // clients of getBindingForElement(). 1113 if (i < 0) 1114 return UndefinedVal(); 1115 int64_t length = Str->getLength(); 1116 // Technically, only i == length is guaranteed to be null. 1117 // However, such overflows should be caught before reaching this point; 1118 // the only time such an access would be made is if a string literal was 1119 // used to initialize a larger array. 1120 char c = (i >= length) ? '\0' : Str->getCodeUnit(i); 1121 return svalBuilder.makeIntVal(c, T); 1122 } 1123 } 1124 1125 // Check for loads from a code text region. For such loads, just give up. 1126 if (isa<CodeTextRegion>(superR)) 1127 return UnknownVal(); 1128 1129 // Handle the case where we are indexing into a larger scalar object. 1130 // For example, this handles: 1131 // int x = ... 1132 // char *y = &x; 1133 // return *y; 1134 // FIXME: This is a hack, and doesn't do anything really intelligent yet. 1135 const RegionRawOffset &O = R->getAsArrayOffset(); 1136 1137 // If we cannot reason about the offset, return an unknown value. 1138 if (!O.getRegion()) 1139 return UnknownVal(); 1140 1141 if (const TypedValueRegion *baseR = 1142 dyn_cast_or_null<TypedValueRegion>(O.getRegion())) { 1143 QualType baseT = baseR->getValueType(); 1144 if (baseT->isScalarType()) { 1145 QualType elemT = R->getElementType(); 1146 if (elemT->isScalarType()) { 1147 if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) { 1148 if (const Optional<SVal> &V = getDirectBinding(B, superR)) { 1149 if (SymbolRef parentSym = V->getAsSymbol()) 1150 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1151 1152 if (V->isUnknownOrUndef()) 1153 return *V; 1154 // Other cases: give up. We are indexing into a larger object 1155 // that has some value, but we don't know how to handle that yet. 1156 return UnknownVal(); 1157 } 1158 } 1159 } 1160 } 1161 } 1162 return getBindingForFieldOrElementCommon(store, R, R->getElementType(), 1163 superR); 1164} 1165 1166SVal RegionStoreManager::getBindingForField(Store store, 1167 const FieldRegion* R) { 1168 1169 // Check if the region has a binding. 1170 RegionBindings B = GetRegionBindings(store); 1171 if (const Optional<SVal> &V = getDirectBinding(B, R)) 1172 return *V; 1173 1174 QualType Ty = R->getValueType(); 1175 return getBindingForFieldOrElementCommon(store, R, Ty, R->getSuperRegion()); 1176} 1177 1178Optional<SVal> 1179RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindings B, 1180 const MemRegion *superR, 1181 const TypedValueRegion *R, 1182 QualType Ty) { 1183 1184 if (const Optional<SVal> &D = getDefaultBinding(B, superR)) { 1185 const SVal &val = D.getValue(); 1186 if (SymbolRef parentSym = val.getAsSymbol()) 1187 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1188 1189 if (val.isZeroConstant()) 1190 return svalBuilder.makeZeroVal(Ty); 1191 1192 if (val.isUnknownOrUndef()) 1193 return val; 1194 1195 // Lazy bindings are handled later. 1196 if (isa<nonloc::LazyCompoundVal>(val)) 1197 return Optional<SVal>(); 1198 1199 llvm_unreachable("Unknown default value"); 1200 } 1201 1202 return Optional<SVal>(); 1203} 1204 1205SVal RegionStoreManager::getLazyBinding(const MemRegion *lazyBindingRegion, 1206 Store lazyBindingStore) { 1207 if (const ElementRegion *ER = dyn_cast<ElementRegion>(lazyBindingRegion)) 1208 return getBindingForElement(lazyBindingStore, ER); 1209 1210 return getBindingForField(lazyBindingStore, 1211 cast<FieldRegion>(lazyBindingRegion)); 1212} 1213 1214SVal RegionStoreManager::getBindingForFieldOrElementCommon(Store store, 1215 const TypedValueRegion *R, 1216 QualType Ty, 1217 const MemRegion *superR) { 1218 1219 // At this point we have already checked in either getBindingForElement or 1220 // getBindingForField if 'R' has a direct binding. 1221 RegionBindings B = GetRegionBindings(store); 1222 1223 // Lazy binding? 1224 Store lazyBindingStore = NULL; 1225 const MemRegion *lazyBindingRegion = NULL; 1226 llvm::tie(lazyBindingStore, lazyBindingRegion) = GetLazyBinding(B, R, R, 1227 true); 1228 1229 if (lazyBindingRegion) 1230 return getLazyBinding(lazyBindingRegion, lazyBindingStore); 1231 1232 // Record whether or not we see a symbolic index. That can completely 1233 // be out of scope of our lookup. 1234 bool hasSymbolicIndex = false; 1235 1236 while (superR) { 1237 if (const Optional<SVal> &D = 1238 getBindingForDerivedDefaultValue(B, superR, R, Ty)) 1239 return *D; 1240 1241 if (const ElementRegion *ER = dyn_cast<ElementRegion>(superR)) { 1242 NonLoc index = ER->getIndex(); 1243 if (!index.isConstant()) 1244 hasSymbolicIndex = true; 1245 } 1246 1247 // If our super region is a field or element itself, walk up the region 1248 // hierarchy to see if there is a default value installed in an ancestor. 1249 if (const SubRegion *SR = dyn_cast<SubRegion>(superR)) { 1250 superR = SR->getSuperRegion(); 1251 continue; 1252 } 1253 break; 1254 } 1255 1256 if (R->hasStackNonParametersStorage()) { 1257 if (isa<ElementRegion>(R)) { 1258 // Currently we don't reason specially about Clang-style vectors. Check 1259 // if superR is a vector and if so return Unknown. 1260 if (const TypedValueRegion *typedSuperR = 1261 dyn_cast<TypedValueRegion>(superR)) { 1262 if (typedSuperR->getValueType()->isVectorType()) 1263 return UnknownVal(); 1264 } 1265 } 1266 1267 // FIXME: We also need to take ElementRegions with symbolic indexes into 1268 // account. This case handles both directly accessing an ElementRegion 1269 // with a symbolic offset, but also fields within an element with 1270 // a symbolic offset. 1271 if (hasSymbolicIndex) 1272 return UnknownVal(); 1273 1274 return UndefinedVal(); 1275 } 1276 1277 // All other values are symbolic. 1278 return svalBuilder.getRegionValueSymbolVal(R); 1279} 1280 1281SVal RegionStoreManager::getBindingForObjCIvar(Store store, 1282 const ObjCIvarRegion* R) { 1283 1284 // Check if the region has a binding. 1285 RegionBindings B = GetRegionBindings(store); 1286 1287 if (const Optional<SVal> &V = getDirectBinding(B, R)) 1288 return *V; 1289 1290 const MemRegion *superR = R->getSuperRegion(); 1291 1292 // Check if the super region has a default binding. 1293 if (const Optional<SVal> &V = getDefaultBinding(B, superR)) { 1294 if (SymbolRef parentSym = V->getAsSymbol()) 1295 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1296 1297 // Other cases: give up. 1298 return UnknownVal(); 1299 } 1300 1301 return getBindingForLazySymbol(R); 1302} 1303 1304SVal RegionStoreManager::getBindingForVar(Store store, const VarRegion *R) { 1305 1306 // Check if the region has a binding. 1307 RegionBindings B = GetRegionBindings(store); 1308 1309 if (const Optional<SVal> &V = getDirectBinding(B, R)) 1310 return *V; 1311 1312 // Lazily derive a value for the VarRegion. 1313 const VarDecl *VD = R->getDecl(); 1314 QualType T = VD->getType(); 1315 const MemSpaceRegion *MS = R->getMemorySpace(); 1316 1317 if (isa<UnknownSpaceRegion>(MS) || 1318 isa<StackArgumentsSpaceRegion>(MS)) 1319 return svalBuilder.getRegionValueSymbolVal(R); 1320 1321 if (isa<GlobalsSpaceRegion>(MS)) { 1322 if (isa<NonStaticGlobalSpaceRegion>(MS)) { 1323 // Is 'VD' declared constant? If so, retrieve the constant value. 1324 QualType CT = Ctx.getCanonicalType(T); 1325 if (CT.isConstQualified()) { 1326 const Expr *Init = VD->getInit(); 1327 // Do the null check first, as we want to call 'IgnoreParenCasts'. 1328 if (Init) 1329 if (const IntegerLiteral *IL = 1330 dyn_cast<IntegerLiteral>(Init->IgnoreParenCasts())) { 1331 const nonloc::ConcreteInt &V = svalBuilder.makeIntVal(IL); 1332 return svalBuilder.evalCast(V, Init->getType(), IL->getType()); 1333 } 1334 } 1335 1336 if (const Optional<SVal> &V 1337 = getBindingForDerivedDefaultValue(B, MS, R, CT)) 1338 return V.getValue(); 1339 1340 return svalBuilder.getRegionValueSymbolVal(R); 1341 } 1342 1343 if (T->isIntegerType()) 1344 return svalBuilder.makeIntVal(0, T); 1345 if (T->isPointerType()) 1346 return svalBuilder.makeNull(); 1347 1348 return UnknownVal(); 1349 } 1350 1351 return UndefinedVal(); 1352} 1353 1354SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) { 1355 // All other values are symbolic. 1356 return svalBuilder.getRegionValueSymbolVal(R); 1357} 1358 1359static bool mayHaveLazyBinding(QualType Ty) { 1360 return Ty->isArrayType() || Ty->isStructureOrClassType(); 1361} 1362 1363SVal RegionStoreManager::getBindingForStruct(Store store, 1364 const TypedValueRegion* R) { 1365 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl(); 1366 if (RD->field_empty()) 1367 return UnknownVal(); 1368 1369 // If we already have a lazy binding, don't create a new one, 1370 // unless the first field might have a lazy binding of its own. 1371 // (Right now we can't tell the difference.) 1372 QualType FirstFieldType = RD->field_begin()->getType(); 1373 if (!mayHaveLazyBinding(FirstFieldType)) { 1374 RegionBindings B = GetRegionBindings(store); 1375 BindingKey K = BindingKey::Make(R, BindingKey::Default); 1376 if (const nonloc::LazyCompoundVal *V = 1377 dyn_cast_or_null<nonloc::LazyCompoundVal>(lookup(B, K))) { 1378 return *V; 1379 } 1380 } 1381 1382 return svalBuilder.makeLazyCompoundVal(StoreRef(store, *this), R); 1383} 1384 1385SVal RegionStoreManager::getBindingForArray(Store store, 1386 const TypedValueRegion * R) { 1387 const ConstantArrayType *Ty = Ctx.getAsConstantArrayType(R->getValueType()); 1388 assert(Ty && "Only constant array types can have compound bindings."); 1389 1390 // If we already have a lazy binding, don't create a new one, 1391 // unless the first element might have a lazy binding of its own. 1392 // (Right now we can't tell the difference.) 1393 if (!mayHaveLazyBinding(Ty->getElementType())) { 1394 RegionBindings B = GetRegionBindings(store); 1395 BindingKey K = BindingKey::Make(R, BindingKey::Default); 1396 if (const nonloc::LazyCompoundVal *V = 1397 dyn_cast_or_null<nonloc::LazyCompoundVal>(lookup(B, K))) { 1398 return *V; 1399 } 1400 } 1401 1402 return svalBuilder.makeLazyCompoundVal(StoreRef(store, *this), R); 1403} 1404 1405bool RegionStoreManager::includedInBindings(Store store, 1406 const MemRegion *region) const { 1407 RegionBindings B = GetRegionBindings(store); 1408 region = region->getBaseRegion(); 1409 1410 // Quick path: if the base is the head of a cluster, the region is live. 1411 if (B.lookup(region)) 1412 return true; 1413 1414 // Slow path: if the region is the VALUE of any binding, it is live. 1415 for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) { 1416 const ClusterBindings &Cluster = RI.getData(); 1417 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1418 CI != CE; ++CI) { 1419 const SVal &D = CI.getData(); 1420 if (const MemRegion *R = D.getAsRegion()) 1421 if (R->getBaseRegion() == region) 1422 return true; 1423 } 1424 } 1425 1426 return false; 1427} 1428 1429//===----------------------------------------------------------------------===// 1430// Binding values to regions. 1431//===----------------------------------------------------------------------===// 1432 1433StoreRef RegionStoreManager::killBinding(Store ST, Loc L) { 1434 if (isa<loc::MemRegionVal>(L)) 1435 if (const MemRegion* R = cast<loc::MemRegionVal>(L).getRegion()) 1436 return StoreRef(removeBinding(GetRegionBindings(ST), 1437 R).getRootWithoutRetain(), 1438 *this); 1439 1440 return StoreRef(ST, *this); 1441} 1442 1443StoreRef RegionStoreManager::Bind(Store store, Loc L, SVal V) { 1444 if (isa<loc::ConcreteInt>(L)) 1445 return StoreRef(store, *this); 1446 1447 // If we get here, the location should be a region. 1448 const MemRegion *R = cast<loc::MemRegionVal>(L).getRegion(); 1449 1450 // Check if the region is a struct region. 1451 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) { 1452 QualType Ty = TR->getValueType(); 1453 if (Ty->isArrayType()) 1454 return BindArray(store, TR, V); 1455 if (Ty->isStructureOrClassType()) 1456 return BindStruct(store, TR, V); 1457 if (Ty->isVectorType()) 1458 return BindVector(store, TR, V); 1459 } 1460 1461 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 1462 // Binding directly to a symbolic region should be treated as binding 1463 // to element 0. 1464 QualType T = SR->getSymbol()->getType(); 1465 if (T->isAnyPointerType() || T->isReferenceType()) 1466 T = T->getPointeeType(); 1467 1468 R = GetElementZeroRegion(SR, T); 1469 } 1470 1471 // Clear out bindings that may overlap with this binding. 1472 1473 // Perform the binding. 1474 RegionBindings B = GetRegionBindings(store); 1475 B = removeSubRegionBindings(B, cast<SubRegion>(R)); 1476 BindingKey Key = BindingKey::Make(R, BindingKey::Direct); 1477 return StoreRef(addBinding(B, Key, V).getRootWithoutRetain(), *this); 1478} 1479 1480// FIXME: this method should be merged into Bind(). 1481StoreRef RegionStoreManager::bindCompoundLiteral(Store ST, 1482 const CompoundLiteralExpr *CL, 1483 const LocationContext *LC, 1484 SVal V) { 1485 return Bind(ST, loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)), V); 1486} 1487 1488StoreRef RegionStoreManager::setImplicitDefaultValue(Store store, 1489 const MemRegion *R, 1490 QualType T) { 1491 RegionBindings B = GetRegionBindings(store); 1492 SVal V; 1493 1494 if (Loc::isLocType(T)) 1495 V = svalBuilder.makeNull(); 1496 else if (T->isIntegerType()) 1497 V = svalBuilder.makeZeroVal(T); 1498 else if (T->isStructureOrClassType() || T->isArrayType()) { 1499 // Set the default value to a zero constant when it is a structure 1500 // or array. The type doesn't really matter. 1501 V = svalBuilder.makeZeroVal(Ctx.IntTy); 1502 } 1503 else { 1504 // We can't represent values of this type, but we still need to set a value 1505 // to record that the region has been initialized. 1506 // If this assertion ever fires, a new case should be added above -- we 1507 // should know how to default-initialize any value we can symbolicate. 1508 assert(!SymbolManager::canSymbolicate(T) && "This type is representable"); 1509 V = UnknownVal(); 1510 } 1511 1512 return StoreRef(addBinding(B, R, BindingKey::Default, 1513 V).getRootWithoutRetain(), *this); 1514} 1515 1516StoreRef RegionStoreManager::BindArray(Store store, const TypedValueRegion* R, 1517 SVal Init) { 1518 1519 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType())); 1520 QualType ElementTy = AT->getElementType(); 1521 Optional<uint64_t> Size; 1522 1523 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT)) 1524 Size = CAT->getSize().getZExtValue(); 1525 1526 // Check if the init expr is a string literal. 1527 if (loc::MemRegionVal *MRV = dyn_cast<loc::MemRegionVal>(&Init)) { 1528 const StringRegion *S = cast<StringRegion>(MRV->getRegion()); 1529 1530 // Treat the string as a lazy compound value. 1531 nonloc::LazyCompoundVal LCV = 1532 cast<nonloc::LazyCompoundVal>(svalBuilder. 1533 makeLazyCompoundVal(StoreRef(store, *this), S)); 1534 return BindAggregate(store, R, LCV); 1535 } 1536 1537 // Handle lazy compound values. 1538 if (isa<nonloc::LazyCompoundVal>(Init)) 1539 return BindAggregate(store, R, Init); 1540 1541 // Remaining case: explicit compound values. 1542 1543 if (Init.isUnknown()) 1544 return setImplicitDefaultValue(store, R, ElementTy); 1545 1546 nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(Init); 1547 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1548 uint64_t i = 0; 1549 1550 StoreRef newStore(store, *this); 1551 for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) { 1552 // The init list might be shorter than the array length. 1553 if (VI == VE) 1554 break; 1555 1556 const NonLoc &Idx = svalBuilder.makeArrayIndex(i); 1557 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx); 1558 1559 if (ElementTy->isStructureOrClassType()) 1560 newStore = BindStruct(newStore.getStore(), ER, *VI); 1561 else if (ElementTy->isArrayType()) 1562 newStore = BindArray(newStore.getStore(), ER, *VI); 1563 else 1564 newStore = Bind(newStore.getStore(), svalBuilder.makeLoc(ER), *VI); 1565 } 1566 1567 // If the init list is shorter than the array length, set the 1568 // array default value. 1569 if (Size.hasValue() && i < Size.getValue()) 1570 newStore = setImplicitDefaultValue(newStore.getStore(), R, ElementTy); 1571 1572 return newStore; 1573} 1574 1575StoreRef RegionStoreManager::BindVector(Store store, const TypedValueRegion* R, 1576 SVal V) { 1577 QualType T = R->getValueType(); 1578 assert(T->isVectorType()); 1579 const VectorType *VT = T->getAs<VectorType>(); // Use getAs for typedefs. 1580 1581 // Handle lazy compound values and symbolic values. 1582 if (isa<nonloc::LazyCompoundVal>(V) || isa<nonloc::SymbolVal>(V)) 1583 return BindAggregate(store, R, V); 1584 1585 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1586 // that we are binding symbolic struct value. Kill the field values, and if 1587 // the value is symbolic go and bind it as a "default" binding. 1588 if (!isa<nonloc::CompoundVal>(V)) { 1589 return BindAggregate(store, R, UnknownVal()); 1590 } 1591 1592 QualType ElemType = VT->getElementType(); 1593 nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(V); 1594 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1595 unsigned index = 0, numElements = VT->getNumElements(); 1596 StoreRef newStore(store, *this); 1597 1598 for ( ; index != numElements ; ++index) { 1599 if (VI == VE) 1600 break; 1601 1602 NonLoc Idx = svalBuilder.makeArrayIndex(index); 1603 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx); 1604 1605 if (ElemType->isArrayType()) 1606 newStore = BindArray(newStore.getStore(), ER, *VI); 1607 else if (ElemType->isStructureOrClassType()) 1608 newStore = BindStruct(newStore.getStore(), ER, *VI); 1609 else 1610 newStore = Bind(newStore.getStore(), svalBuilder.makeLoc(ER), *VI); 1611 } 1612 return newStore; 1613} 1614 1615StoreRef RegionStoreManager::BindStruct(Store store, const TypedValueRegion* R, 1616 SVal V) { 1617 1618 if (!Features.supportsFields()) 1619 return StoreRef(store, *this); 1620 1621 QualType T = R->getValueType(); 1622 assert(T->isStructureOrClassType()); 1623 1624 const RecordType* RT = T->getAs<RecordType>(); 1625 RecordDecl *RD = RT->getDecl(); 1626 1627 if (!RD->isCompleteDefinition()) 1628 return StoreRef(store, *this); 1629 1630 // Handle lazy compound values and symbolic values. 1631 if (isa<nonloc::LazyCompoundVal>(V) || isa<nonloc::SymbolVal>(V)) 1632 return BindAggregate(store, R, V); 1633 1634 // We may get non-CompoundVal accidentally due to imprecise cast logic or 1635 // that we are binding symbolic struct value. Kill the field values, and if 1636 // the value is symbolic go and bind it as a "default" binding. 1637 if (V.isUnknown() || !isa<nonloc::CompoundVal>(V)) 1638 return BindAggregate(store, R, UnknownVal()); 1639 1640 nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(V); 1641 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 1642 1643 RecordDecl::field_iterator FI, FE; 1644 StoreRef newStore(store, *this); 1645 1646 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) { 1647 1648 if (VI == VE) 1649 break; 1650 1651 // Skip any unnamed bitfields to stay in sync with the initializers. 1652 if (FI->isUnnamedBitfield()) 1653 continue; 1654 1655 QualType FTy = FI->getType(); 1656 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R); 1657 1658 if (FTy->isArrayType()) 1659 newStore = BindArray(newStore.getStore(), FR, *VI); 1660 else if (FTy->isStructureOrClassType()) 1661 newStore = BindStruct(newStore.getStore(), FR, *VI); 1662 else 1663 newStore = Bind(newStore.getStore(), svalBuilder.makeLoc(FR), *VI); 1664 ++VI; 1665 } 1666 1667 // There may be fewer values in the initialize list than the fields of struct. 1668 if (FI != FE) { 1669 RegionBindings B = GetRegionBindings(newStore.getStore()); 1670 B = addBinding(B, R, BindingKey::Default, svalBuilder.makeIntVal(0, false)); 1671 newStore = StoreRef(B.getRootWithoutRetain(), *this); 1672 } 1673 1674 return newStore; 1675} 1676 1677StoreRef RegionStoreManager::BindAggregate(Store store, const TypedRegion *R, 1678 SVal Val) { 1679 // Remove the old bindings, using 'R' as the root of all regions 1680 // we will invalidate. Then add the new binding. 1681 RegionBindings B = GetRegionBindings(store); 1682 1683 B = removeSubRegionBindings(B, R); 1684 B = addBinding(B, R, BindingKey::Default, Val); 1685 1686 return StoreRef(B.getRootWithoutRetain(), *this); 1687} 1688 1689//===----------------------------------------------------------------------===// 1690// "Raw" retrievals and bindings. 1691//===----------------------------------------------------------------------===// 1692 1693 1694RegionBindings RegionStoreManager::addBinding(RegionBindings B, BindingKey K, 1695 SVal V) { 1696 const MemRegion *Base = K.getBaseRegion(); 1697 1698 const ClusterBindings *ExistingCluster = B.lookup(Base); 1699 ClusterBindings Cluster = (ExistingCluster ? *ExistingCluster 1700 : CBFactory.getEmptyMap()); 1701 1702 ClusterBindings NewCluster = CBFactory.add(Cluster, K, V); 1703 return RBFactory.add(B, Base, NewCluster); 1704} 1705 1706RegionBindings RegionStoreManager::addBinding(RegionBindings B, 1707 const MemRegion *R, 1708 BindingKey::Kind k, SVal V) { 1709 return addBinding(B, BindingKey::Make(R, k), V); 1710} 1711 1712const SVal *RegionStoreManager::lookup(RegionBindings B, BindingKey K) { 1713 const ClusterBindings *Cluster = B.lookup(K.getBaseRegion()); 1714 if (!Cluster) 1715 return 0; 1716 1717 return Cluster->lookup(K); 1718} 1719 1720const SVal *RegionStoreManager::lookup(RegionBindings B, 1721 const MemRegion *R, 1722 BindingKey::Kind k) { 1723 return lookup(B, BindingKey::Make(R, k)); 1724} 1725 1726RegionBindings RegionStoreManager::removeBinding(RegionBindings B, 1727 BindingKey K) { 1728 const MemRegion *Base = K.getBaseRegion(); 1729 const ClusterBindings *Cluster = B.lookup(Base); 1730 if (!Cluster) 1731 return B; 1732 1733 ClusterBindings NewCluster = CBFactory.remove(*Cluster, K); 1734 if (NewCluster.isEmpty()) 1735 return RBFactory.remove(B, Base); 1736 return RBFactory.add(B, Base, NewCluster); 1737} 1738 1739RegionBindings RegionStoreManager::removeBinding(RegionBindings B, 1740 const MemRegion *R, 1741 BindingKey::Kind k){ 1742 return removeBinding(B, BindingKey::Make(R, k)); 1743} 1744 1745RegionBindings RegionStoreManager::removeCluster(RegionBindings B, 1746 const MemRegion *Base) { 1747 return RBFactory.remove(B, Base); 1748} 1749 1750//===----------------------------------------------------------------------===// 1751// State pruning. 1752//===----------------------------------------------------------------------===// 1753 1754namespace { 1755class removeDeadBindingsWorker : 1756 public ClusterAnalysis<removeDeadBindingsWorker> { 1757 SmallVector<const SymbolicRegion*, 12> Postponed; 1758 SymbolReaper &SymReaper; 1759 const StackFrameContext *CurrentLCtx; 1760 1761public: 1762 removeDeadBindingsWorker(RegionStoreManager &rm, 1763 ProgramStateManager &stateMgr, 1764 RegionBindings b, SymbolReaper &symReaper, 1765 const StackFrameContext *LCtx) 1766 : ClusterAnalysis<removeDeadBindingsWorker>(rm, stateMgr, b, 1767 /* includeGlobals = */ false), 1768 SymReaper(symReaper), CurrentLCtx(LCtx) {} 1769 1770 // Called by ClusterAnalysis. 1771 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C); 1772 void VisitCluster(const MemRegion *baseR, const ClusterBindings &C); 1773 1774 bool UpdatePostponed(); 1775 void VisitBinding(SVal V); 1776}; 1777} 1778 1779void removeDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR, 1780 const ClusterBindings &C) { 1781 1782 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) { 1783 if (SymReaper.isLive(VR)) 1784 AddToWorkList(baseR, &C); 1785 1786 return; 1787 } 1788 1789 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 1790 if (SymReaper.isLive(SR->getSymbol())) 1791 AddToWorkList(SR, &C); 1792 else 1793 Postponed.push_back(SR); 1794 1795 return; 1796 } 1797 1798 if (isa<NonStaticGlobalSpaceRegion>(baseR)) { 1799 AddToWorkList(baseR, &C); 1800 return; 1801 } 1802 1803 // CXXThisRegion in the current or parent location context is live. 1804 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) { 1805 const StackArgumentsSpaceRegion *StackReg = 1806 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion()); 1807 const StackFrameContext *RegCtx = StackReg->getStackFrame(); 1808 if (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx)) 1809 AddToWorkList(TR, &C); 1810 } 1811} 1812 1813void removeDeadBindingsWorker::VisitCluster(const MemRegion *baseR, 1814 const ClusterBindings &C) { 1815 // Mark the symbol for any SymbolicRegion with live bindings as live itself. 1816 // This means we should continue to track that symbol. 1817 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR)) 1818 SymReaper.markLive(SymR->getSymbol()); 1819 1820 for (ClusterBindings::iterator I = C.begin(), E = C.end(); I != E; ++I) 1821 VisitBinding(I.getData()); 1822} 1823 1824void removeDeadBindingsWorker::VisitBinding(SVal V) { 1825 // Is it a LazyCompoundVal? All referenced regions are live as well. 1826 if (const nonloc::LazyCompoundVal *LCS = 1827 dyn_cast<nonloc::LazyCompoundVal>(&V)) { 1828 1829 const MemRegion *LazyR = LCS->getRegion(); 1830 RegionBindings B = RegionStoreManager::GetRegionBindings(LCS->getStore()); 1831 1832 // FIXME: This should not have to walk all bindings in the old store. 1833 for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI){ 1834 const ClusterBindings &Cluster = RI.getData(); 1835 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1836 CI != CE; ++CI) { 1837 BindingKey K = CI.getKey(); 1838 if (const SubRegion *BaseR = dyn_cast<SubRegion>(K.getRegion())) { 1839 if (BaseR == LazyR) 1840 VisitBinding(CI.getData()); 1841 else if (K.hasSymbolicOffset() && BaseR->isSubRegionOf(LazyR)) 1842 VisitBinding(CI.getData()); 1843 } 1844 } 1845 } 1846 1847 return; 1848 } 1849 1850 // If V is a region, then add it to the worklist. 1851 if (const MemRegion *R = V.getAsRegion()) { 1852 AddToWorkList(R); 1853 1854 // All regions captured by a block are also live. 1855 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) { 1856 BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(), 1857 E = BR->referenced_vars_end(); 1858 for ( ; I != E; ++I) 1859 AddToWorkList(I.getCapturedRegion()); 1860 } 1861 } 1862 1863 1864 // Update the set of live symbols. 1865 for (SymExpr::symbol_iterator SI = V.symbol_begin(), SE = V.symbol_end(); 1866 SI!=SE; ++SI) 1867 SymReaper.markLive(*SI); 1868} 1869 1870bool removeDeadBindingsWorker::UpdatePostponed() { 1871 // See if any postponed SymbolicRegions are actually live now, after 1872 // having done a scan. 1873 bool changed = false; 1874 1875 for (SmallVectorImpl<const SymbolicRegion*>::iterator 1876 I = Postponed.begin(), E = Postponed.end() ; I != E ; ++I) { 1877 if (const SymbolicRegion *SR = *I) { 1878 if (SymReaper.isLive(SR->getSymbol())) { 1879 changed |= AddToWorkList(SR); 1880 *I = NULL; 1881 } 1882 } 1883 } 1884 1885 return changed; 1886} 1887 1888StoreRef RegionStoreManager::removeDeadBindings(Store store, 1889 const StackFrameContext *LCtx, 1890 SymbolReaper& SymReaper) { 1891 RegionBindings B = GetRegionBindings(store); 1892 removeDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx); 1893 W.GenerateClusters(); 1894 1895 // Enqueue the region roots onto the worklist. 1896 for (SymbolReaper::region_iterator I = SymReaper.region_begin(), 1897 E = SymReaper.region_end(); I != E; ++I) { 1898 W.AddToWorkList(*I); 1899 } 1900 1901 do W.RunWorkList(); while (W.UpdatePostponed()); 1902 1903 // We have now scanned the store, marking reachable regions and symbols 1904 // as live. We now remove all the regions that are dead from the store 1905 // as well as update DSymbols with the set symbols that are now dead. 1906 for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 1907 const MemRegion *Base = I.getKey(); 1908 1909 // If the cluster has been visited, we know the region has been marked. 1910 if (W.isVisited(Base)) 1911 continue; 1912 1913 // Remove the dead entry. 1914 B = removeCluster(B, Base); 1915 1916 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Base)) 1917 SymReaper.maybeDead(SymR->getSymbol()); 1918 1919 // Mark all non-live symbols that this binding references as dead. 1920 const ClusterBindings &Cluster = I.getData(); 1921 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1922 CI != CE; ++CI) { 1923 SVal X = CI.getData(); 1924 SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end(); 1925 for (; SI != SE; ++SI) 1926 SymReaper.maybeDead(*SI); 1927 } 1928 } 1929 1930 return StoreRef(B.getRootWithoutRetain(), *this); 1931} 1932 1933//===----------------------------------------------------------------------===// 1934// Utility methods. 1935//===----------------------------------------------------------------------===// 1936 1937void RegionStoreManager::print(Store store, raw_ostream &OS, 1938 const char* nl, const char *sep) { 1939 RegionBindings B = GetRegionBindings(store); 1940 OS << "Store (direct and default bindings), " 1941 << (void*) B.getRootWithoutRetain() 1942 << " :" << nl; 1943 1944 for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 1945 const ClusterBindings &Cluster = I.getData(); 1946 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 1947 CI != CE; ++CI) { 1948 OS << ' ' << CI.getKey() << " : " << CI.getData() << nl; 1949 } 1950 OS << nl; 1951 } 1952} 1953