RegionStore.cpp revision 360784
1//== RegionStore.cpp - Field-sensitive store model --------------*- C++ -*--==// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// This file defines a basic region store model. In this model, we do have field 10// sensitivity. But we assume nothing about the heap shape. So recursive data 11// structures are largely ignored. Basically we do 1-limiting analysis. 12// Parameter pointers are assumed with no aliasing. Pointee objects of 13// parameters are created lazily. 14// 15//===----------------------------------------------------------------------===// 16 17#include "clang/AST/Attr.h" 18#include "clang/AST/CharUnits.h" 19#include "clang/ASTMatchers/ASTMatchFinder.h" 20#include "clang/Analysis/Analyses/LiveVariables.h" 21#include "clang/Analysis/AnalysisDeclContext.h" 22#include "clang/Basic/JsonSupport.h" 23#include "clang/Basic/TargetInfo.h" 24#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h" 25#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 26#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 27#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" 28#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 29#include "clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h" 30#include "llvm/ADT/ImmutableMap.h" 31#include "llvm/ADT/Optional.h" 32#include "llvm/Support/raw_ostream.h" 33#include <utility> 34 35using namespace clang; 36using namespace ento; 37 38//===----------------------------------------------------------------------===// 39// Representation of binding keys. 40//===----------------------------------------------------------------------===// 41 42namespace { 43class BindingKey { 44public: 45 enum Kind { Default = 0x0, Direct = 0x1 }; 46private: 47 enum { Symbolic = 0x2 }; 48 49 llvm::PointerIntPair<const MemRegion *, 2> P; 50 uint64_t Data; 51 52 /// Create a key for a binding to region \p r, which has a symbolic offset 53 /// from region \p Base. 54 explicit BindingKey(const SubRegion *r, const SubRegion *Base, Kind k) 55 : P(r, k | Symbolic), Data(reinterpret_cast<uintptr_t>(Base)) { 56 assert(r && Base && "Must have known regions."); 57 assert(getConcreteOffsetRegion() == Base && "Failed to store base region"); 58 } 59 60 /// Create a key for a binding at \p offset from base region \p r. 61 explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k) 62 : P(r, k), Data(offset) { 63 assert(r && "Must have known regions."); 64 assert(getOffset() == offset && "Failed to store offset"); 65 assert((r == r->getBaseRegion() || isa<ObjCIvarRegion>(r) || 66 isa <CXXDerivedObjectRegion>(r)) && 67 "Not a base"); 68 } 69public: 70 71 bool isDirect() const { return P.getInt() & Direct; } 72 bool hasSymbolicOffset() const { return P.getInt() & Symbolic; } 73 74 const MemRegion *getRegion() const { return P.getPointer(); } 75 uint64_t getOffset() const { 76 assert(!hasSymbolicOffset()); 77 return Data; 78 } 79 80 const SubRegion *getConcreteOffsetRegion() const { 81 assert(hasSymbolicOffset()); 82 return reinterpret_cast<const SubRegion *>(static_cast<uintptr_t>(Data)); 83 } 84 85 const MemRegion *getBaseRegion() const { 86 if (hasSymbolicOffset()) 87 return getConcreteOffsetRegion()->getBaseRegion(); 88 return getRegion()->getBaseRegion(); 89 } 90 91 void Profile(llvm::FoldingSetNodeID& ID) const { 92 ID.AddPointer(P.getOpaqueValue()); 93 ID.AddInteger(Data); 94 } 95 96 static BindingKey Make(const MemRegion *R, Kind k); 97 98 bool operator<(const BindingKey &X) const { 99 if (P.getOpaqueValue() < X.P.getOpaqueValue()) 100 return true; 101 if (P.getOpaqueValue() > X.P.getOpaqueValue()) 102 return false; 103 return Data < X.Data; 104 } 105 106 bool operator==(const BindingKey &X) const { 107 return P.getOpaqueValue() == X.P.getOpaqueValue() && 108 Data == X.Data; 109 } 110 111 LLVM_DUMP_METHOD void dump() const; 112}; 113} // end anonymous namespace 114 115BindingKey BindingKey::Make(const MemRegion *R, Kind k) { 116 const RegionOffset &RO = R->getAsOffset(); 117 if (RO.hasSymbolicOffset()) 118 return BindingKey(cast<SubRegion>(R), cast<SubRegion>(RO.getRegion()), k); 119 120 return BindingKey(RO.getRegion(), RO.getOffset(), k); 121} 122 123namespace llvm { 124static inline raw_ostream &operator<<(raw_ostream &Out, BindingKey K) { 125 Out << "\"kind\": \"" << (K.isDirect() ? "Direct" : "Default") 126 << "\", \"offset\": "; 127 128 if (!K.hasSymbolicOffset()) 129 Out << K.getOffset(); 130 else 131 Out << "null"; 132 133 return Out; 134} 135 136} // namespace llvm 137 138#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 139void BindingKey::dump() const { llvm::errs() << *this; } 140#endif 141 142//===----------------------------------------------------------------------===// 143// Actual Store type. 144//===----------------------------------------------------------------------===// 145 146typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings; 147typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef; 148typedef std::pair<BindingKey, SVal> BindingPair; 149 150typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings> 151 RegionBindings; 152 153namespace { 154class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *, 155 ClusterBindings> { 156 ClusterBindings::Factory *CBFactory; 157 158 // This flag indicates whether the current bindings are within the analysis 159 // that has started from main(). It affects how we perform loads from 160 // global variables that have initializers: if we have observed the 161 // program execution from the start and we know that these variables 162 // have not been overwritten yet, we can be sure that their initializers 163 // are still relevant. This flag never gets changed when the bindings are 164 // updated, so it could potentially be moved into RegionStoreManager 165 // (as if it's the same bindings but a different loading procedure) 166 // however that would have made the manager needlessly stateful. 167 bool IsMainAnalysis; 168 169public: 170 typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings> 171 ParentTy; 172 173 RegionBindingsRef(ClusterBindings::Factory &CBFactory, 174 const RegionBindings::TreeTy *T, 175 RegionBindings::TreeTy::Factory *F, 176 bool IsMainAnalysis) 177 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F), 178 CBFactory(&CBFactory), IsMainAnalysis(IsMainAnalysis) {} 179 180 RegionBindingsRef(const ParentTy &P, 181 ClusterBindings::Factory &CBFactory, 182 bool IsMainAnalysis) 183 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P), 184 CBFactory(&CBFactory), IsMainAnalysis(IsMainAnalysis) {} 185 186 RegionBindingsRef add(key_type_ref K, data_type_ref D) const { 187 return RegionBindingsRef(static_cast<const ParentTy *>(this)->add(K, D), 188 *CBFactory, IsMainAnalysis); 189 } 190 191 RegionBindingsRef remove(key_type_ref K) const { 192 return RegionBindingsRef(static_cast<const ParentTy *>(this)->remove(K), 193 *CBFactory, IsMainAnalysis); 194 } 195 196 RegionBindingsRef addBinding(BindingKey K, SVal V) const; 197 198 RegionBindingsRef addBinding(const MemRegion *R, 199 BindingKey::Kind k, SVal V) const; 200 201 const SVal *lookup(BindingKey K) const; 202 const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const; 203 using llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>::lookup; 204 205 RegionBindingsRef removeBinding(BindingKey K); 206 207 RegionBindingsRef removeBinding(const MemRegion *R, 208 BindingKey::Kind k); 209 210 RegionBindingsRef removeBinding(const MemRegion *R) { 211 return removeBinding(R, BindingKey::Direct). 212 removeBinding(R, BindingKey::Default); 213 } 214 215 Optional<SVal> getDirectBinding(const MemRegion *R) const; 216 217 /// getDefaultBinding - Returns an SVal* representing an optional default 218 /// binding associated with a region and its subregions. 219 Optional<SVal> getDefaultBinding(const MemRegion *R) const; 220 221 /// Return the internal tree as a Store. 222 Store asStore() const { 223 llvm::PointerIntPair<Store, 1, bool> Ptr = { 224 asImmutableMap().getRootWithoutRetain(), IsMainAnalysis}; 225 return reinterpret_cast<Store>(Ptr.getOpaqueValue()); 226 } 227 228 bool isMainAnalysis() const { 229 return IsMainAnalysis; 230 } 231 232 void printJson(raw_ostream &Out, const char *NL = "\n", 233 unsigned int Space = 0, bool IsDot = false) const { 234 for (iterator I = begin(); I != end(); ++I) { 235 // TODO: We might need a .printJson for I.getKey() as well. 236 Indent(Out, Space, IsDot) 237 << "{ \"cluster\": \"" << I.getKey() << "\", \"pointer\": \"" 238 << (const void *)I.getKey() << "\", \"items\": [" << NL; 239 240 ++Space; 241 const ClusterBindings &CB = I.getData(); 242 for (ClusterBindings::iterator CI = CB.begin(); CI != CB.end(); ++CI) { 243 Indent(Out, Space, IsDot) << "{ " << CI.getKey() << ", \"value\": "; 244 CI.getData().printJson(Out, /*AddQuotes=*/true); 245 Out << " }"; 246 if (std::next(CI) != CB.end()) 247 Out << ','; 248 Out << NL; 249 } 250 251 --Space; 252 Indent(Out, Space, IsDot) << "]}"; 253 if (std::next(I) != end()) 254 Out << ','; 255 Out << NL; 256 } 257 } 258 259 LLVM_DUMP_METHOD void dump() const { printJson(llvm::errs()); } 260}; 261} // end anonymous namespace 262 263typedef const RegionBindingsRef& RegionBindingsConstRef; 264 265Optional<SVal> RegionBindingsRef::getDirectBinding(const MemRegion *R) const { 266 return Optional<SVal>::create(lookup(R, BindingKey::Direct)); 267} 268 269Optional<SVal> RegionBindingsRef::getDefaultBinding(const MemRegion *R) const { 270 return Optional<SVal>::create(lookup(R, BindingKey::Default)); 271} 272 273RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const { 274 const MemRegion *Base = K.getBaseRegion(); 275 276 const ClusterBindings *ExistingCluster = lookup(Base); 277 ClusterBindings Cluster = 278 (ExistingCluster ? *ExistingCluster : CBFactory->getEmptyMap()); 279 280 ClusterBindings NewCluster = CBFactory->add(Cluster, K, V); 281 return add(Base, NewCluster); 282} 283 284 285RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R, 286 BindingKey::Kind k, 287 SVal V) const { 288 return addBinding(BindingKey::Make(R, k), V); 289} 290 291const SVal *RegionBindingsRef::lookup(BindingKey K) const { 292 const ClusterBindings *Cluster = lookup(K.getBaseRegion()); 293 if (!Cluster) 294 return nullptr; 295 return Cluster->lookup(K); 296} 297 298const SVal *RegionBindingsRef::lookup(const MemRegion *R, 299 BindingKey::Kind k) const { 300 return lookup(BindingKey::Make(R, k)); 301} 302 303RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) { 304 const MemRegion *Base = K.getBaseRegion(); 305 const ClusterBindings *Cluster = lookup(Base); 306 if (!Cluster) 307 return *this; 308 309 ClusterBindings NewCluster = CBFactory->remove(*Cluster, K); 310 if (NewCluster.isEmpty()) 311 return remove(Base); 312 return add(Base, NewCluster); 313} 314 315RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R, 316 BindingKey::Kind k){ 317 return removeBinding(BindingKey::Make(R, k)); 318} 319 320//===----------------------------------------------------------------------===// 321// Fine-grained control of RegionStoreManager. 322//===----------------------------------------------------------------------===// 323 324namespace { 325struct minimal_features_tag {}; 326struct maximal_features_tag {}; 327 328class RegionStoreFeatures { 329 bool SupportsFields; 330public: 331 RegionStoreFeatures(minimal_features_tag) : 332 SupportsFields(false) {} 333 334 RegionStoreFeatures(maximal_features_tag) : 335 SupportsFields(true) {} 336 337 void enableFields(bool t) { SupportsFields = t; } 338 339 bool supportsFields() const { return SupportsFields; } 340}; 341} 342 343//===----------------------------------------------------------------------===// 344// Main RegionStore logic. 345//===----------------------------------------------------------------------===// 346 347namespace { 348class InvalidateRegionsWorker; 349 350class RegionStoreManager : public StoreManager { 351public: 352 const RegionStoreFeatures Features; 353 354 RegionBindings::Factory RBFactory; 355 mutable ClusterBindings::Factory CBFactory; 356 357 typedef std::vector<SVal> SValListTy; 358private: 359 typedef llvm::DenseMap<const LazyCompoundValData *, 360 SValListTy> LazyBindingsMapTy; 361 LazyBindingsMapTy LazyBindingsMap; 362 363 /// The largest number of fields a struct can have and still be 364 /// considered "small". 365 /// 366 /// This is currently used to decide whether or not it is worth "forcing" a 367 /// LazyCompoundVal on bind. 368 /// 369 /// This is controlled by 'region-store-small-struct-limit' option. 370 /// To disable all small-struct-dependent behavior, set the option to "0". 371 unsigned SmallStructLimit; 372 373 /// A helper used to populate the work list with the given set of 374 /// regions. 375 void populateWorkList(InvalidateRegionsWorker &W, 376 ArrayRef<SVal> Values, 377 InvalidatedRegions *TopLevelRegions); 378 379public: 380 RegionStoreManager(ProgramStateManager& mgr, const RegionStoreFeatures &f) 381 : StoreManager(mgr), Features(f), 382 RBFactory(mgr.getAllocator()), CBFactory(mgr.getAllocator()), 383 SmallStructLimit(0) { 384 SubEngine &Eng = StateMgr.getOwningEngine(); 385 AnalyzerOptions &Options = Eng.getAnalysisManager().options; 386 SmallStructLimit = Options.RegionStoreSmallStructLimit; 387 } 388 389 390 /// setImplicitDefaultValue - Set the default binding for the provided 391 /// MemRegion to the value implicitly defined for compound literals when 392 /// the value is not specified. 393 RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B, 394 const MemRegion *R, QualType T); 395 396 /// ArrayToPointer - Emulates the "decay" of an array to a pointer 397 /// type. 'Array' represents the lvalue of the array being decayed 398 /// to a pointer, and the returned SVal represents the decayed 399 /// version of that lvalue (i.e., a pointer to the first element of 400 /// the array). This is called by ExprEngine when evaluating 401 /// casts from arrays to pointers. 402 SVal ArrayToPointer(Loc Array, QualType ElementTy) override; 403 404 /// Creates the Store that correctly represents memory contents before 405 /// the beginning of the analysis of the given top-level stack frame. 406 StoreRef getInitialStore(const LocationContext *InitLoc) override { 407 bool IsMainAnalysis = false; 408 if (const auto *FD = dyn_cast<FunctionDecl>(InitLoc->getDecl())) 409 IsMainAnalysis = FD->isMain() && !Ctx.getLangOpts().CPlusPlus; 410 return StoreRef(RegionBindingsRef( 411 RegionBindingsRef::ParentTy(RBFactory.getEmptyMap(), RBFactory), 412 CBFactory, IsMainAnalysis).asStore(), *this); 413 } 414 415 //===-------------------------------------------------------------------===// 416 // Binding values to regions. 417 //===-------------------------------------------------------------------===// 418 RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K, 419 const Expr *Ex, 420 unsigned Count, 421 const LocationContext *LCtx, 422 RegionBindingsRef B, 423 InvalidatedRegions *Invalidated); 424 425 StoreRef invalidateRegions(Store store, 426 ArrayRef<SVal> Values, 427 const Expr *E, unsigned Count, 428 const LocationContext *LCtx, 429 const CallEvent *Call, 430 InvalidatedSymbols &IS, 431 RegionAndSymbolInvalidationTraits &ITraits, 432 InvalidatedRegions *Invalidated, 433 InvalidatedRegions *InvalidatedTopLevel) override; 434 435 bool scanReachableSymbols(Store S, const MemRegion *R, 436 ScanReachableSymbols &Callbacks) override; 437 438 RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B, 439 const SubRegion *R); 440 441public: // Part of public interface to class. 442 443 StoreRef Bind(Store store, Loc LV, SVal V) override { 444 return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this); 445 } 446 447 RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V); 448 449 // BindDefaultInitial is only used to initialize a region with 450 // a default value. 451 StoreRef BindDefaultInitial(Store store, const MemRegion *R, 452 SVal V) override { 453 RegionBindingsRef B = getRegionBindings(store); 454 // Use other APIs when you have to wipe the region that was initialized 455 // earlier. 456 assert(!(B.getDefaultBinding(R) || B.getDirectBinding(R)) && 457 "Double initialization!"); 458 B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V); 459 return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this); 460 } 461 462 // BindDefaultZero is used for zeroing constructors that may accidentally 463 // overwrite existing bindings. 464 StoreRef BindDefaultZero(Store store, const MemRegion *R) override { 465 // FIXME: The offsets of empty bases can be tricky because of 466 // of the so called "empty base class optimization". 467 // If a base class has been optimized out 468 // we should not try to create a binding, otherwise we should. 469 // Unfortunately, at the moment ASTRecordLayout doesn't expose 470 // the actual sizes of the empty bases 471 // and trying to infer them from offsets/alignments 472 // seems to be error-prone and non-trivial because of the trailing padding. 473 // As a temporary mitigation we don't create bindings for empty bases. 474 if (const auto *BR = dyn_cast<CXXBaseObjectRegion>(R)) 475 if (BR->getDecl()->isEmpty()) 476 return StoreRef(store, *this); 477 478 RegionBindingsRef B = getRegionBindings(store); 479 SVal V = svalBuilder.makeZeroVal(Ctx.CharTy); 480 B = removeSubRegionBindings(B, cast<SubRegion>(R)); 481 B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V); 482 return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this); 483 } 484 485 /// Attempt to extract the fields of \p LCV and bind them to the struct region 486 /// \p R. 487 /// 488 /// This path is used when it seems advantageous to "force" loading the values 489 /// within a LazyCompoundVal to bind memberwise to the struct region, rather 490 /// than using a Default binding at the base of the entire region. This is a 491 /// heuristic attempting to avoid building long chains of LazyCompoundVals. 492 /// 493 /// \returns The updated store bindings, or \c None if binding non-lazily 494 /// would be too expensive. 495 Optional<RegionBindingsRef> tryBindSmallStruct(RegionBindingsConstRef B, 496 const TypedValueRegion *R, 497 const RecordDecl *RD, 498 nonloc::LazyCompoundVal LCV); 499 500 /// BindStruct - Bind a compound value to a structure. 501 RegionBindingsRef bindStruct(RegionBindingsConstRef B, 502 const TypedValueRegion* R, SVal V); 503 504 /// BindVector - Bind a compound value to a vector. 505 RegionBindingsRef bindVector(RegionBindingsConstRef B, 506 const TypedValueRegion* R, SVal V); 507 508 RegionBindingsRef bindArray(RegionBindingsConstRef B, 509 const TypedValueRegion* R, 510 SVal V); 511 512 /// Clears out all bindings in the given region and assigns a new value 513 /// as a Default binding. 514 RegionBindingsRef bindAggregate(RegionBindingsConstRef B, 515 const TypedRegion *R, 516 SVal DefaultVal); 517 518 /// Create a new store with the specified binding removed. 519 /// \param ST the original store, that is the basis for the new store. 520 /// \param L the location whose binding should be removed. 521 StoreRef killBinding(Store ST, Loc L) override; 522 523 void incrementReferenceCount(Store store) override { 524 getRegionBindings(store).manualRetain(); 525 } 526 527 /// If the StoreManager supports it, decrement the reference count of 528 /// the specified Store object. If the reference count hits 0, the memory 529 /// associated with the object is recycled. 530 void decrementReferenceCount(Store store) override { 531 getRegionBindings(store).manualRelease(); 532 } 533 534 bool includedInBindings(Store store, const MemRegion *region) const override; 535 536 /// Return the value bound to specified location in a given state. 537 /// 538 /// The high level logic for this method is this: 539 /// getBinding (L) 540 /// if L has binding 541 /// return L's binding 542 /// else if L is in killset 543 /// return unknown 544 /// else 545 /// if L is on stack or heap 546 /// return undefined 547 /// else 548 /// return symbolic 549 SVal getBinding(Store S, Loc L, QualType T) override { 550 return getBinding(getRegionBindings(S), L, T); 551 } 552 553 Optional<SVal> getDefaultBinding(Store S, const MemRegion *R) override { 554 RegionBindingsRef B = getRegionBindings(S); 555 // Default bindings are always applied over a base region so look up the 556 // base region's default binding, otherwise the lookup will fail when R 557 // is at an offset from R->getBaseRegion(). 558 return B.getDefaultBinding(R->getBaseRegion()); 559 } 560 561 SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType()); 562 563 SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R); 564 565 SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R); 566 567 SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R); 568 569 SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R); 570 571 SVal getBindingForLazySymbol(const TypedValueRegion *R); 572 573 SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 574 const TypedValueRegion *R, 575 QualType Ty); 576 577 SVal getLazyBinding(const SubRegion *LazyBindingRegion, 578 RegionBindingsRef LazyBinding); 579 580 /// Get bindings for the values in a struct and return a CompoundVal, used 581 /// when doing struct copy: 582 /// struct s x, y; 583 /// x = y; 584 /// y's value is retrieved by this method. 585 SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R); 586 SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R); 587 NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R); 588 589 /// Used to lazily generate derived symbols for bindings that are defined 590 /// implicitly by default bindings in a super region. 591 /// 592 /// Note that callers may need to specially handle LazyCompoundVals, which 593 /// are returned as is in case the caller needs to treat them differently. 594 Optional<SVal> getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 595 const MemRegion *superR, 596 const TypedValueRegion *R, 597 QualType Ty); 598 599 /// Get the state and region whose binding this region \p R corresponds to. 600 /// 601 /// If there is no lazy binding for \p R, the returned value will have a null 602 /// \c second. Note that a null pointer can represents a valid Store. 603 std::pair<Store, const SubRegion *> 604 findLazyBinding(RegionBindingsConstRef B, const SubRegion *R, 605 const SubRegion *originalRegion); 606 607 /// Returns the cached set of interesting SVals contained within a lazy 608 /// binding. 609 /// 610 /// The precise value of "interesting" is determined for the purposes of 611 /// RegionStore's internal analysis. It must always contain all regions and 612 /// symbols, but may omit constants and other kinds of SVal. 613 const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV); 614 615 //===------------------------------------------------------------------===// 616 // State pruning. 617 //===------------------------------------------------------------------===// 618 619 /// removeDeadBindings - Scans the RegionStore of 'state' for dead values. 620 /// It returns a new Store with these values removed. 621 StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, 622 SymbolReaper& SymReaper) override; 623 624 //===------------------------------------------------------------------===// 625 // Region "extents". 626 //===------------------------------------------------------------------===// 627 628 // FIXME: This method will soon be eliminated; see the note in Store.h. 629 DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state, 630 const MemRegion* R, 631 QualType EleTy) override; 632 633 //===------------------------------------------------------------------===// 634 // Utility methods. 635 //===------------------------------------------------------------------===// 636 637 RegionBindingsRef getRegionBindings(Store store) const { 638 llvm::PointerIntPair<Store, 1, bool> Ptr; 639 Ptr.setFromOpaqueValue(const_cast<void *>(store)); 640 return RegionBindingsRef( 641 CBFactory, 642 static_cast<const RegionBindings::TreeTy *>(Ptr.getPointer()), 643 RBFactory.getTreeFactory(), 644 Ptr.getInt()); 645 } 646 647 void printJson(raw_ostream &Out, Store S, const char *NL = "\n", 648 unsigned int Space = 0, bool IsDot = false) const override; 649 650 void iterBindings(Store store, BindingsHandler& f) override { 651 RegionBindingsRef B = getRegionBindings(store); 652 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 653 const ClusterBindings &Cluster = I.getData(); 654 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 655 CI != CE; ++CI) { 656 const BindingKey &K = CI.getKey(); 657 if (!K.isDirect()) 658 continue; 659 if (const SubRegion *R = dyn_cast<SubRegion>(K.getRegion())) { 660 // FIXME: Possibly incorporate the offset? 661 if (!f.HandleBinding(*this, store, R, CI.getData())) 662 return; 663 } 664 } 665 } 666 } 667}; 668 669} // end anonymous namespace 670 671//===----------------------------------------------------------------------===// 672// RegionStore creation. 673//===----------------------------------------------------------------------===// 674 675std::unique_ptr<StoreManager> 676ento::CreateRegionStoreManager(ProgramStateManager &StMgr) { 677 RegionStoreFeatures F = maximal_features_tag(); 678 return std::make_unique<RegionStoreManager>(StMgr, F); 679} 680 681std::unique_ptr<StoreManager> 682ento::CreateFieldsOnlyRegionStoreManager(ProgramStateManager &StMgr) { 683 RegionStoreFeatures F = minimal_features_tag(); 684 F.enableFields(true); 685 return std::make_unique<RegionStoreManager>(StMgr, F); 686} 687 688 689//===----------------------------------------------------------------------===// 690// Region Cluster analysis. 691//===----------------------------------------------------------------------===// 692 693namespace { 694/// Used to determine which global regions are automatically included in the 695/// initial worklist of a ClusterAnalysis. 696enum GlobalsFilterKind { 697 /// Don't include any global regions. 698 GFK_None, 699 /// Only include system globals. 700 GFK_SystemOnly, 701 /// Include all global regions. 702 GFK_All 703}; 704 705template <typename DERIVED> 706class ClusterAnalysis { 707protected: 708 typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap; 709 typedef const MemRegion * WorkListElement; 710 typedef SmallVector<WorkListElement, 10> WorkList; 711 712 llvm::SmallPtrSet<const ClusterBindings *, 16> Visited; 713 714 WorkList WL; 715 716 RegionStoreManager &RM; 717 ASTContext &Ctx; 718 SValBuilder &svalBuilder; 719 720 RegionBindingsRef B; 721 722 723protected: 724 const ClusterBindings *getCluster(const MemRegion *R) { 725 return B.lookup(R); 726 } 727 728 /// Returns true if all clusters in the given memspace should be initially 729 /// included in the cluster analysis. Subclasses may provide their 730 /// own implementation. 731 bool includeEntireMemorySpace(const MemRegion *Base) { 732 return false; 733 } 734 735public: 736 ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr, 737 RegionBindingsRef b) 738 : RM(rm), Ctx(StateMgr.getContext()), 739 svalBuilder(StateMgr.getSValBuilder()), B(std::move(b)) {} 740 741 RegionBindingsRef getRegionBindings() const { return B; } 742 743 bool isVisited(const MemRegion *R) { 744 return Visited.count(getCluster(R)); 745 } 746 747 void GenerateClusters() { 748 // Scan the entire set of bindings and record the region clusters. 749 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); 750 RI != RE; ++RI){ 751 const MemRegion *Base = RI.getKey(); 752 753 const ClusterBindings &Cluster = RI.getData(); 754 assert(!Cluster.isEmpty() && "Empty clusters should be removed"); 755 static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster); 756 757 // If the base's memspace should be entirely invalidated, add the cluster 758 // to the workspace up front. 759 if (static_cast<DERIVED*>(this)->includeEntireMemorySpace(Base)) 760 AddToWorkList(WorkListElement(Base), &Cluster); 761 } 762 } 763 764 bool AddToWorkList(WorkListElement E, const ClusterBindings *C) { 765 if (C && !Visited.insert(C).second) 766 return false; 767 WL.push_back(E); 768 return true; 769 } 770 771 bool AddToWorkList(const MemRegion *R) { 772 return static_cast<DERIVED*>(this)->AddToWorkList(R); 773 } 774 775 void RunWorkList() { 776 while (!WL.empty()) { 777 WorkListElement E = WL.pop_back_val(); 778 const MemRegion *BaseR = E; 779 780 static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR)); 781 } 782 } 783 784 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {} 785 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {} 786 787 void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C, 788 bool Flag) { 789 static_cast<DERIVED*>(this)->VisitCluster(BaseR, C); 790 } 791}; 792} 793 794//===----------------------------------------------------------------------===// 795// Binding invalidation. 796//===----------------------------------------------------------------------===// 797 798bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R, 799 ScanReachableSymbols &Callbacks) { 800 assert(R == R->getBaseRegion() && "Should only be called for base regions"); 801 RegionBindingsRef B = getRegionBindings(S); 802 const ClusterBindings *Cluster = B.lookup(R); 803 804 if (!Cluster) 805 return true; 806 807 for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end(); 808 RI != RE; ++RI) { 809 if (!Callbacks.scan(RI.getData())) 810 return false; 811 } 812 813 return true; 814} 815 816static inline bool isUnionField(const FieldRegion *FR) { 817 return FR->getDecl()->getParent()->isUnion(); 818} 819 820typedef SmallVector<const FieldDecl *, 8> FieldVector; 821 822static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) { 823 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 824 825 const MemRegion *Base = K.getConcreteOffsetRegion(); 826 const MemRegion *R = K.getRegion(); 827 828 while (R != Base) { 829 if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) 830 if (!isUnionField(FR)) 831 Fields.push_back(FR->getDecl()); 832 833 R = cast<SubRegion>(R)->getSuperRegion(); 834 } 835} 836 837static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) { 838 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 839 840 if (Fields.empty()) 841 return true; 842 843 FieldVector FieldsInBindingKey; 844 getSymbolicOffsetFields(K, FieldsInBindingKey); 845 846 ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size(); 847 if (Delta >= 0) 848 return std::equal(FieldsInBindingKey.begin() + Delta, 849 FieldsInBindingKey.end(), 850 Fields.begin()); 851 else 852 return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(), 853 Fields.begin() - Delta); 854} 855 856/// Collects all bindings in \p Cluster that may refer to bindings within 857/// \p Top. 858/// 859/// Each binding is a pair whose \c first is the key (a BindingKey) and whose 860/// \c second is the value (an SVal). 861/// 862/// The \p IncludeAllDefaultBindings parameter specifies whether to include 863/// default bindings that may extend beyond \p Top itself, e.g. if \p Top is 864/// an aggregate within a larger aggregate with a default binding. 865static void 866collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 867 SValBuilder &SVB, const ClusterBindings &Cluster, 868 const SubRegion *Top, BindingKey TopKey, 869 bool IncludeAllDefaultBindings) { 870 FieldVector FieldsInSymbolicSubregions; 871 if (TopKey.hasSymbolicOffset()) { 872 getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions); 873 Top = TopKey.getConcreteOffsetRegion(); 874 TopKey = BindingKey::Make(Top, BindingKey::Default); 875 } 876 877 // Find the length (in bits) of the region being invalidated. 878 uint64_t Length = UINT64_MAX; 879 SVal Extent = Top->getExtent(SVB); 880 if (Optional<nonloc::ConcreteInt> ExtentCI = 881 Extent.getAs<nonloc::ConcreteInt>()) { 882 const llvm::APSInt &ExtentInt = ExtentCI->getValue(); 883 assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned()); 884 // Extents are in bytes but region offsets are in bits. Be careful! 885 Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth(); 886 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) { 887 if (FR->getDecl()->isBitField()) 888 Length = FR->getDecl()->getBitWidthValue(SVB.getContext()); 889 } 890 891 for (ClusterBindings::iterator I = Cluster.begin(), E = Cluster.end(); 892 I != E; ++I) { 893 BindingKey NextKey = I.getKey(); 894 if (NextKey.getRegion() == TopKey.getRegion()) { 895 // FIXME: This doesn't catch the case where we're really invalidating a 896 // region with a symbolic offset. Example: 897 // R: points[i].y 898 // Next: points[0].x 899 900 if (NextKey.getOffset() > TopKey.getOffset() && 901 NextKey.getOffset() - TopKey.getOffset() < Length) { 902 // Case 1: The next binding is inside the region we're invalidating. 903 // Include it. 904 Bindings.push_back(*I); 905 906 } else if (NextKey.getOffset() == TopKey.getOffset()) { 907 // Case 2: The next binding is at the same offset as the region we're 908 // invalidating. In this case, we need to leave default bindings alone, 909 // since they may be providing a default value for a regions beyond what 910 // we're invalidating. 911 // FIXME: This is probably incorrect; consider invalidating an outer 912 // struct whose first field is bound to a LazyCompoundVal. 913 if (IncludeAllDefaultBindings || NextKey.isDirect()) 914 Bindings.push_back(*I); 915 } 916 917 } else if (NextKey.hasSymbolicOffset()) { 918 const MemRegion *Base = NextKey.getConcreteOffsetRegion(); 919 if (Top->isSubRegionOf(Base) && Top != Base) { 920 // Case 3: The next key is symbolic and we just changed something within 921 // its concrete region. We don't know if the binding is still valid, so 922 // we'll be conservative and include it. 923 if (IncludeAllDefaultBindings || NextKey.isDirect()) 924 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 925 Bindings.push_back(*I); 926 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) { 927 // Case 4: The next key is symbolic, but we changed a known 928 // super-region. In this case the binding is certainly included. 929 if (BaseSR->isSubRegionOf(Top)) 930 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 931 Bindings.push_back(*I); 932 } 933 } 934 } 935} 936 937static void 938collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 939 SValBuilder &SVB, const ClusterBindings &Cluster, 940 const SubRegion *Top, bool IncludeAllDefaultBindings) { 941 collectSubRegionBindings(Bindings, SVB, Cluster, Top, 942 BindingKey::Make(Top, BindingKey::Default), 943 IncludeAllDefaultBindings); 944} 945 946RegionBindingsRef 947RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B, 948 const SubRegion *Top) { 949 BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default); 950 const MemRegion *ClusterHead = TopKey.getBaseRegion(); 951 952 if (Top == ClusterHead) { 953 // We can remove an entire cluster's bindings all in one go. 954 return B.remove(Top); 955 } 956 957 const ClusterBindings *Cluster = B.lookup(ClusterHead); 958 if (!Cluster) { 959 // If we're invalidating a region with a symbolic offset, we need to make 960 // sure we don't treat the base region as uninitialized anymore. 961 if (TopKey.hasSymbolicOffset()) { 962 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 963 return B.addBinding(Concrete, BindingKey::Default, UnknownVal()); 964 } 965 return B; 966 } 967 968 SmallVector<BindingPair, 32> Bindings; 969 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey, 970 /*IncludeAllDefaultBindings=*/false); 971 972 ClusterBindingsRef Result(*Cluster, CBFactory); 973 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 974 E = Bindings.end(); 975 I != E; ++I) 976 Result = Result.remove(I->first); 977 978 // If we're invalidating a region with a symbolic offset, we need to make sure 979 // we don't treat the base region as uninitialized anymore. 980 // FIXME: This isn't very precise; see the example in 981 // collectSubRegionBindings. 982 if (TopKey.hasSymbolicOffset()) { 983 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 984 Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default), 985 UnknownVal()); 986 } 987 988 if (Result.isEmpty()) 989 return B.remove(ClusterHead); 990 return B.add(ClusterHead, Result.asImmutableMap()); 991} 992 993namespace { 994class InvalidateRegionsWorker : public ClusterAnalysis<InvalidateRegionsWorker> 995{ 996 const Expr *Ex; 997 unsigned Count; 998 const LocationContext *LCtx; 999 InvalidatedSymbols &IS; 1000 RegionAndSymbolInvalidationTraits &ITraits; 1001 StoreManager::InvalidatedRegions *Regions; 1002 GlobalsFilterKind GlobalsFilter; 1003public: 1004 InvalidateRegionsWorker(RegionStoreManager &rm, 1005 ProgramStateManager &stateMgr, 1006 RegionBindingsRef b, 1007 const Expr *ex, unsigned count, 1008 const LocationContext *lctx, 1009 InvalidatedSymbols &is, 1010 RegionAndSymbolInvalidationTraits &ITraitsIn, 1011 StoreManager::InvalidatedRegions *r, 1012 GlobalsFilterKind GFK) 1013 : ClusterAnalysis<InvalidateRegionsWorker>(rm, stateMgr, b), 1014 Ex(ex), Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r), 1015 GlobalsFilter(GFK) {} 1016 1017 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C); 1018 void VisitBinding(SVal V); 1019 1020 using ClusterAnalysis::AddToWorkList; 1021 1022 bool AddToWorkList(const MemRegion *R); 1023 1024 /// Returns true if all clusters in the memory space for \p Base should be 1025 /// be invalidated. 1026 bool includeEntireMemorySpace(const MemRegion *Base); 1027 1028 /// Returns true if the memory space of the given region is one of the global 1029 /// regions specially included at the start of invalidation. 1030 bool isInitiallyIncludedGlobalRegion(const MemRegion *R); 1031}; 1032} 1033 1034bool InvalidateRegionsWorker::AddToWorkList(const MemRegion *R) { 1035 bool doNotInvalidateSuperRegion = ITraits.hasTrait( 1036 R, RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion); 1037 const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion(); 1038 return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR)); 1039} 1040 1041void InvalidateRegionsWorker::VisitBinding(SVal V) { 1042 // A symbol? Mark it touched by the invalidation. 1043 if (SymbolRef Sym = V.getAsSymbol()) 1044 IS.insert(Sym); 1045 1046 if (const MemRegion *R = V.getAsRegion()) { 1047 AddToWorkList(R); 1048 return; 1049 } 1050 1051 // Is it a LazyCompoundVal? All references get invalidated as well. 1052 if (Optional<nonloc::LazyCompoundVal> LCS = 1053 V.getAs<nonloc::LazyCompoundVal>()) { 1054 1055 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 1056 1057 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 1058 E = Vals.end(); 1059 I != E; ++I) 1060 VisitBinding(*I); 1061 1062 return; 1063 } 1064} 1065 1066void InvalidateRegionsWorker::VisitCluster(const MemRegion *baseR, 1067 const ClusterBindings *C) { 1068 1069 bool PreserveRegionsContents = 1070 ITraits.hasTrait(baseR, 1071 RegionAndSymbolInvalidationTraits::TK_PreserveContents); 1072 1073 if (C) { 1074 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) 1075 VisitBinding(I.getData()); 1076 1077 // Invalidate regions contents. 1078 if (!PreserveRegionsContents) 1079 B = B.remove(baseR); 1080 } 1081 1082 if (const auto *TO = dyn_cast<TypedValueRegion>(baseR)) { 1083 if (const auto *RD = TO->getValueType()->getAsCXXRecordDecl()) { 1084 1085 // Lambdas can affect all static local variables without explicitly 1086 // capturing those. 1087 // We invalidate all static locals referenced inside the lambda body. 1088 if (RD->isLambda() && RD->getLambdaCallOperator()->getBody()) { 1089 using namespace ast_matchers; 1090 1091 const char *DeclBind = "DeclBind"; 1092 StatementMatcher RefToStatic = stmt(hasDescendant(declRefExpr( 1093 to(varDecl(hasStaticStorageDuration()).bind(DeclBind))))); 1094 auto Matches = 1095 match(RefToStatic, *RD->getLambdaCallOperator()->getBody(), 1096 RD->getASTContext()); 1097 1098 for (BoundNodes &Match : Matches) { 1099 auto *VD = Match.getNodeAs<VarDecl>(DeclBind); 1100 const VarRegion *ToInvalidate = 1101 RM.getRegionManager().getVarRegion(VD, LCtx); 1102 AddToWorkList(ToInvalidate); 1103 } 1104 } 1105 } 1106 } 1107 1108 // BlockDataRegion? If so, invalidate captured variables that are passed 1109 // by reference. 1110 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) { 1111 for (BlockDataRegion::referenced_vars_iterator 1112 BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ; 1113 BI != BE; ++BI) { 1114 const VarRegion *VR = BI.getCapturedRegion(); 1115 const VarDecl *VD = VR->getDecl(); 1116 if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage()) { 1117 AddToWorkList(VR); 1118 } 1119 else if (Loc::isLocType(VR->getValueType())) { 1120 // Map the current bindings to a Store to retrieve the value 1121 // of the binding. If that binding itself is a region, we should 1122 // invalidate that region. This is because a block may capture 1123 // a pointer value, but the thing pointed by that pointer may 1124 // get invalidated. 1125 SVal V = RM.getBinding(B, loc::MemRegionVal(VR)); 1126 if (Optional<Loc> L = V.getAs<Loc>()) { 1127 if (const MemRegion *LR = L->getAsRegion()) 1128 AddToWorkList(LR); 1129 } 1130 } 1131 } 1132 return; 1133 } 1134 1135 // Symbolic region? 1136 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) 1137 IS.insert(SR->getSymbol()); 1138 1139 // Nothing else should be done in the case when we preserve regions context. 1140 if (PreserveRegionsContents) 1141 return; 1142 1143 // Otherwise, we have a normal data region. Record that we touched the region. 1144 if (Regions) 1145 Regions->push_back(baseR); 1146 1147 if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) { 1148 // Invalidate the region by setting its default value to 1149 // conjured symbol. The type of the symbol is irrelevant. 1150 DefinedOrUnknownSVal V = 1151 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count); 1152 B = B.addBinding(baseR, BindingKey::Default, V); 1153 return; 1154 } 1155 1156 if (!baseR->isBoundable()) 1157 return; 1158 1159 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR); 1160 QualType T = TR->getValueType(); 1161 1162 if (isInitiallyIncludedGlobalRegion(baseR)) { 1163 // If the region is a global and we are invalidating all globals, 1164 // erasing the entry is good enough. This causes all globals to be lazily 1165 // symbolicated from the same base symbol. 1166 return; 1167 } 1168 1169 if (T->isRecordType()) { 1170 // Invalidate the region by setting its default value to 1171 // conjured symbol. The type of the symbol is irrelevant. 1172 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1173 Ctx.IntTy, Count); 1174 B = B.addBinding(baseR, BindingKey::Default, V); 1175 return; 1176 } 1177 1178 if (const ArrayType *AT = Ctx.getAsArrayType(T)) { 1179 bool doNotInvalidateSuperRegion = ITraits.hasTrait( 1180 baseR, 1181 RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion); 1182 1183 if (doNotInvalidateSuperRegion) { 1184 // We are not doing blank invalidation of the whole array region so we 1185 // have to manually invalidate each elements. 1186 Optional<uint64_t> NumElements; 1187 1188 // Compute lower and upper offsets for region within array. 1189 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT)) 1190 NumElements = CAT->getSize().getZExtValue(); 1191 if (!NumElements) // We are not dealing with a constant size array 1192 goto conjure_default; 1193 QualType ElementTy = AT->getElementType(); 1194 uint64_t ElemSize = Ctx.getTypeSize(ElementTy); 1195 const RegionOffset &RO = baseR->getAsOffset(); 1196 const MemRegion *SuperR = baseR->getBaseRegion(); 1197 if (RO.hasSymbolicOffset()) { 1198 // If base region has a symbolic offset, 1199 // we revert to invalidating the super region. 1200 if (SuperR) 1201 AddToWorkList(SuperR); 1202 goto conjure_default; 1203 } 1204 1205 uint64_t LowerOffset = RO.getOffset(); 1206 uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize; 1207 bool UpperOverflow = UpperOffset < LowerOffset; 1208 1209 // Invalidate regions which are within array boundaries, 1210 // or have a symbolic offset. 1211 if (!SuperR) 1212 goto conjure_default; 1213 1214 const ClusterBindings *C = B.lookup(SuperR); 1215 if (!C) 1216 goto conjure_default; 1217 1218 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; 1219 ++I) { 1220 const BindingKey &BK = I.getKey(); 1221 Optional<uint64_t> ROffset = 1222 BK.hasSymbolicOffset() ? Optional<uint64_t>() : BK.getOffset(); 1223 1224 // Check offset is not symbolic and within array's boundaries. 1225 // Handles arrays of 0 elements and of 0-sized elements as well. 1226 if (!ROffset || 1227 ((*ROffset >= LowerOffset && *ROffset < UpperOffset) || 1228 (UpperOverflow && 1229 (*ROffset >= LowerOffset || *ROffset < UpperOffset)) || 1230 (LowerOffset == UpperOffset && *ROffset == LowerOffset))) { 1231 B = B.removeBinding(I.getKey()); 1232 // Bound symbolic regions need to be invalidated for dead symbol 1233 // detection. 1234 SVal V = I.getData(); 1235 const MemRegion *R = V.getAsRegion(); 1236 if (R && isa<SymbolicRegion>(R)) 1237 VisitBinding(V); 1238 } 1239 } 1240 } 1241 conjure_default: 1242 // Set the default value of the array to conjured symbol. 1243 DefinedOrUnknownSVal V = 1244 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1245 AT->getElementType(), Count); 1246 B = B.addBinding(baseR, BindingKey::Default, V); 1247 return; 1248 } 1249 1250 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1251 T,Count); 1252 assert(SymbolManager::canSymbolicate(T) || V.isUnknown()); 1253 B = B.addBinding(baseR, BindingKey::Direct, V); 1254} 1255 1256bool InvalidateRegionsWorker::isInitiallyIncludedGlobalRegion( 1257 const MemRegion *R) { 1258 switch (GlobalsFilter) { 1259 case GFK_None: 1260 return false; 1261 case GFK_SystemOnly: 1262 return isa<GlobalSystemSpaceRegion>(R->getMemorySpace()); 1263 case GFK_All: 1264 return isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace()); 1265 } 1266 1267 llvm_unreachable("unknown globals filter"); 1268} 1269 1270bool InvalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) { 1271 if (isInitiallyIncludedGlobalRegion(Base)) 1272 return true; 1273 1274 const MemSpaceRegion *MemSpace = Base->getMemorySpace(); 1275 return ITraits.hasTrait(MemSpace, 1276 RegionAndSymbolInvalidationTraits::TK_EntireMemSpace); 1277} 1278 1279RegionBindingsRef 1280RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K, 1281 const Expr *Ex, 1282 unsigned Count, 1283 const LocationContext *LCtx, 1284 RegionBindingsRef B, 1285 InvalidatedRegions *Invalidated) { 1286 // Bind the globals memory space to a new symbol that we will use to derive 1287 // the bindings for all globals. 1288 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K); 1289 SVal V = svalBuilder.conjureSymbolVal(/* symbolTag = */ (const void*) GS, Ex, LCtx, 1290 /* type does not matter */ Ctx.IntTy, 1291 Count); 1292 1293 B = B.removeBinding(GS) 1294 .addBinding(BindingKey::Make(GS, BindingKey::Default), V); 1295 1296 // Even if there are no bindings in the global scope, we still need to 1297 // record that we touched it. 1298 if (Invalidated) 1299 Invalidated->push_back(GS); 1300 1301 return B; 1302} 1303 1304void RegionStoreManager::populateWorkList(InvalidateRegionsWorker &W, 1305 ArrayRef<SVal> Values, 1306 InvalidatedRegions *TopLevelRegions) { 1307 for (ArrayRef<SVal>::iterator I = Values.begin(), 1308 E = Values.end(); I != E; ++I) { 1309 SVal V = *I; 1310 if (Optional<nonloc::LazyCompoundVal> LCS = 1311 V.getAs<nonloc::LazyCompoundVal>()) { 1312 1313 const SValListTy &Vals = getInterestingValues(*LCS); 1314 1315 for (SValListTy::const_iterator I = Vals.begin(), 1316 E = Vals.end(); I != E; ++I) { 1317 // Note: the last argument is false here because these are 1318 // non-top-level regions. 1319 if (const MemRegion *R = (*I).getAsRegion()) 1320 W.AddToWorkList(R); 1321 } 1322 continue; 1323 } 1324 1325 if (const MemRegion *R = V.getAsRegion()) { 1326 if (TopLevelRegions) 1327 TopLevelRegions->push_back(R); 1328 W.AddToWorkList(R); 1329 continue; 1330 } 1331 } 1332} 1333 1334StoreRef 1335RegionStoreManager::invalidateRegions(Store store, 1336 ArrayRef<SVal> Values, 1337 const Expr *Ex, unsigned Count, 1338 const LocationContext *LCtx, 1339 const CallEvent *Call, 1340 InvalidatedSymbols &IS, 1341 RegionAndSymbolInvalidationTraits &ITraits, 1342 InvalidatedRegions *TopLevelRegions, 1343 InvalidatedRegions *Invalidated) { 1344 GlobalsFilterKind GlobalsFilter; 1345 if (Call) { 1346 if (Call->isInSystemHeader()) 1347 GlobalsFilter = GFK_SystemOnly; 1348 else 1349 GlobalsFilter = GFK_All; 1350 } else { 1351 GlobalsFilter = GFK_None; 1352 } 1353 1354 RegionBindingsRef B = getRegionBindings(store); 1355 InvalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, ITraits, 1356 Invalidated, GlobalsFilter); 1357 1358 // Scan the bindings and generate the clusters. 1359 W.GenerateClusters(); 1360 1361 // Add the regions to the worklist. 1362 populateWorkList(W, Values, TopLevelRegions); 1363 1364 W.RunWorkList(); 1365 1366 // Return the new bindings. 1367 B = W.getRegionBindings(); 1368 1369 // For calls, determine which global regions should be invalidated and 1370 // invalidate them. (Note that function-static and immutable globals are never 1371 // invalidated by this.) 1372 // TODO: This could possibly be more precise with modules. 1373 switch (GlobalsFilter) { 1374 case GFK_All: 1375 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind, 1376 Ex, Count, LCtx, B, Invalidated); 1377 LLVM_FALLTHROUGH; 1378 case GFK_SystemOnly: 1379 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1380 Ex, Count, LCtx, B, Invalidated); 1381 LLVM_FALLTHROUGH; 1382 case GFK_None: 1383 break; 1384 } 1385 1386 return StoreRef(B.asStore(), *this); 1387} 1388 1389//===----------------------------------------------------------------------===// 1390// Extents for regions. 1391//===----------------------------------------------------------------------===// 1392 1393DefinedOrUnknownSVal 1394RegionStoreManager::getSizeInElements(ProgramStateRef state, 1395 const MemRegion *R, 1396 QualType EleTy) { 1397 SVal Size = cast<SubRegion>(R)->getExtent(svalBuilder); 1398 const llvm::APSInt *SizeInt = svalBuilder.getKnownValue(state, Size); 1399 if (!SizeInt) 1400 return UnknownVal(); 1401 1402 CharUnits RegionSize = CharUnits::fromQuantity(SizeInt->getSExtValue()); 1403 1404 if (Ctx.getAsVariableArrayType(EleTy)) { 1405 // FIXME: We need to track extra state to properly record the size 1406 // of VLAs. Returning UnknownVal here, however, is a stop-gap so that 1407 // we don't have a divide-by-zero below. 1408 return UnknownVal(); 1409 } 1410 1411 CharUnits EleSize = Ctx.getTypeSizeInChars(EleTy); 1412 1413 // If a variable is reinterpreted as a type that doesn't fit into a larger 1414 // type evenly, round it down. 1415 // This is a signed value, since it's used in arithmetic with signed indices. 1416 return svalBuilder.makeIntVal(RegionSize / EleSize, 1417 svalBuilder.getArrayIndexType()); 1418} 1419 1420//===----------------------------------------------------------------------===// 1421// Location and region casting. 1422//===----------------------------------------------------------------------===// 1423 1424/// ArrayToPointer - Emulates the "decay" of an array to a pointer 1425/// type. 'Array' represents the lvalue of the array being decayed 1426/// to a pointer, and the returned SVal represents the decayed 1427/// version of that lvalue (i.e., a pointer to the first element of 1428/// the array). This is called by ExprEngine when evaluating casts 1429/// from arrays to pointers. 1430SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) { 1431 if (Array.getAs<loc::ConcreteInt>()) 1432 return Array; 1433 1434 if (!Array.getAs<loc::MemRegionVal>()) 1435 return UnknownVal(); 1436 1437 const SubRegion *R = 1438 cast<SubRegion>(Array.castAs<loc::MemRegionVal>().getRegion()); 1439 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex(); 1440 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, R, Ctx)); 1441} 1442 1443//===----------------------------------------------------------------------===// 1444// Loading values from regions. 1445//===----------------------------------------------------------------------===// 1446 1447SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) { 1448 assert(!L.getAs<UnknownVal>() && "location unknown"); 1449 assert(!L.getAs<UndefinedVal>() && "location undefined"); 1450 1451 // For access to concrete addresses, return UnknownVal. Checks 1452 // for null dereferences (and similar errors) are done by checkers, not 1453 // the Store. 1454 // FIXME: We can consider lazily symbolicating such memory, but we really 1455 // should defer this when we can reason easily about symbolicating arrays 1456 // of bytes. 1457 if (L.getAs<loc::ConcreteInt>()) { 1458 return UnknownVal(); 1459 } 1460 if (!L.getAs<loc::MemRegionVal>()) { 1461 return UnknownVal(); 1462 } 1463 1464 const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion(); 1465 1466 if (isa<BlockDataRegion>(MR)) { 1467 return UnknownVal(); 1468 } 1469 1470 if (!isa<TypedValueRegion>(MR)) { 1471 if (T.isNull()) { 1472 if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR)) 1473 T = TR->getLocationType()->getPointeeType(); 1474 else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR)) 1475 T = SR->getSymbol()->getType()->getPointeeType(); 1476 } 1477 assert(!T.isNull() && "Unable to auto-detect binding type!"); 1478 assert(!T->isVoidType() && "Attempting to dereference a void pointer!"); 1479 MR = GetElementZeroRegion(cast<SubRegion>(MR), T); 1480 } else { 1481 T = cast<TypedValueRegion>(MR)->getValueType(); 1482 } 1483 1484 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument 1485 // instead of 'Loc', and have the other Loc cases handled at a higher level. 1486 const TypedValueRegion *R = cast<TypedValueRegion>(MR); 1487 QualType RTy = R->getValueType(); 1488 1489 // FIXME: we do not yet model the parts of a complex type, so treat the 1490 // whole thing as "unknown". 1491 if (RTy->isAnyComplexType()) 1492 return UnknownVal(); 1493 1494 // FIXME: We should eventually handle funny addressing. e.g.: 1495 // 1496 // int x = ...; 1497 // int *p = &x; 1498 // char *q = (char*) p; 1499 // char c = *q; // returns the first byte of 'x'. 1500 // 1501 // Such funny addressing will occur due to layering of regions. 1502 if (RTy->isStructureOrClassType()) 1503 return getBindingForStruct(B, R); 1504 1505 // FIXME: Handle unions. 1506 if (RTy->isUnionType()) 1507 return createLazyBinding(B, R); 1508 1509 if (RTy->isArrayType()) { 1510 if (RTy->isConstantArrayType()) 1511 return getBindingForArray(B, R); 1512 else 1513 return UnknownVal(); 1514 } 1515 1516 // FIXME: handle Vector types. 1517 if (RTy->isVectorType()) 1518 return UnknownVal(); 1519 1520 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R)) 1521 return CastRetrievedVal(getBindingForField(B, FR), FR, T); 1522 1523 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) { 1524 // FIXME: Here we actually perform an implicit conversion from the loaded 1525 // value to the element type. Eventually we want to compose these values 1526 // more intelligently. For example, an 'element' can encompass multiple 1527 // bound regions (e.g., several bound bytes), or could be a subset of 1528 // a larger value. 1529 return CastRetrievedVal(getBindingForElement(B, ER), ER, T); 1530 } 1531 1532 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) { 1533 // FIXME: Here we actually perform an implicit conversion from the loaded 1534 // value to the ivar type. What we should model is stores to ivars 1535 // that blow past the extent of the ivar. If the address of the ivar is 1536 // reinterpretted, it is possible we stored a different value that could 1537 // fit within the ivar. Either we need to cast these when storing them 1538 // or reinterpret them lazily (as we do here). 1539 return CastRetrievedVal(getBindingForObjCIvar(B, IVR), IVR, T); 1540 } 1541 1542 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { 1543 // FIXME: Here we actually perform an implicit conversion from the loaded 1544 // value to the variable type. What we should model is stores to variables 1545 // that blow past the extent of the variable. If the address of the 1546 // variable is reinterpretted, it is possible we stored a different value 1547 // that could fit within the variable. Either we need to cast these when 1548 // storing them or reinterpret them lazily (as we do here). 1549 return CastRetrievedVal(getBindingForVar(B, VR), VR, T); 1550 } 1551 1552 const SVal *V = B.lookup(R, BindingKey::Direct); 1553 1554 // Check if the region has a binding. 1555 if (V) 1556 return *V; 1557 1558 // The location does not have a bound value. This means that it has 1559 // the value it had upon its creation and/or entry to the analyzed 1560 // function/method. These are either symbolic values or 'undefined'. 1561 if (R->hasStackNonParametersStorage()) { 1562 // All stack variables are considered to have undefined values 1563 // upon creation. All heap allocated blocks are considered to 1564 // have undefined values as well unless they are explicitly bound 1565 // to specific values. 1566 return UndefinedVal(); 1567 } 1568 1569 // All other values are symbolic. 1570 return svalBuilder.getRegionValueSymbolVal(R); 1571} 1572 1573static QualType getUnderlyingType(const SubRegion *R) { 1574 QualType RegionTy; 1575 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) 1576 RegionTy = TVR->getValueType(); 1577 1578 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 1579 RegionTy = SR->getSymbol()->getType(); 1580 1581 return RegionTy; 1582} 1583 1584/// Checks to see if store \p B has a lazy binding for region \p R. 1585/// 1586/// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected 1587/// if there are additional bindings within \p R. 1588/// 1589/// Note that unlike RegionStoreManager::findLazyBinding, this will not search 1590/// for lazy bindings for super-regions of \p R. 1591static Optional<nonloc::LazyCompoundVal> 1592getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B, 1593 const SubRegion *R, bool AllowSubregionBindings) { 1594 Optional<SVal> V = B.getDefaultBinding(R); 1595 if (!V) 1596 return None; 1597 1598 Optional<nonloc::LazyCompoundVal> LCV = V->getAs<nonloc::LazyCompoundVal>(); 1599 if (!LCV) 1600 return None; 1601 1602 // If the LCV is for a subregion, the types might not match, and we shouldn't 1603 // reuse the binding. 1604 QualType RegionTy = getUnderlyingType(R); 1605 if (!RegionTy.isNull() && 1606 !RegionTy->isVoidPointerType()) { 1607 QualType SourceRegionTy = LCV->getRegion()->getValueType(); 1608 if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy)) 1609 return None; 1610 } 1611 1612 if (!AllowSubregionBindings) { 1613 // If there are any other bindings within this region, we shouldn't reuse 1614 // the top-level binding. 1615 SmallVector<BindingPair, 16> Bindings; 1616 collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R, 1617 /*IncludeAllDefaultBindings=*/true); 1618 if (Bindings.size() > 1) 1619 return None; 1620 } 1621 1622 return *LCV; 1623} 1624 1625 1626std::pair<Store, const SubRegion *> 1627RegionStoreManager::findLazyBinding(RegionBindingsConstRef B, 1628 const SubRegion *R, 1629 const SubRegion *originalRegion) { 1630 if (originalRegion != R) { 1631 if (Optional<nonloc::LazyCompoundVal> V = 1632 getExistingLazyBinding(svalBuilder, B, R, true)) 1633 return std::make_pair(V->getStore(), V->getRegion()); 1634 } 1635 1636 typedef std::pair<Store, const SubRegion *> StoreRegionPair; 1637 StoreRegionPair Result = StoreRegionPair(); 1638 1639 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 1640 Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()), 1641 originalRegion); 1642 1643 if (Result.second) 1644 Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second); 1645 1646 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) { 1647 Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()), 1648 originalRegion); 1649 1650 if (Result.second) 1651 Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second); 1652 1653 } else if (const CXXBaseObjectRegion *BaseReg = 1654 dyn_cast<CXXBaseObjectRegion>(R)) { 1655 // C++ base object region is another kind of region that we should blast 1656 // through to look for lazy compound value. It is like a field region. 1657 Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()), 1658 originalRegion); 1659 1660 if (Result.second) 1661 Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg, 1662 Result.second); 1663 } 1664 1665 return Result; 1666} 1667 1668SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B, 1669 const ElementRegion* R) { 1670 // We do not currently model bindings of the CompoundLiteralregion. 1671 if (isa<CompoundLiteralRegion>(R->getBaseRegion())) 1672 return UnknownVal(); 1673 1674 // Check if the region has a binding. 1675 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1676 return *V; 1677 1678 const MemRegion* superR = R->getSuperRegion(); 1679 1680 // Check if the region is an element region of a string literal. 1681 if (const StringRegion *StrR = dyn_cast<StringRegion>(superR)) { 1682 // FIXME: Handle loads from strings where the literal is treated as 1683 // an integer, e.g., *((unsigned int*)"hello") 1684 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType(); 1685 if (!Ctx.hasSameUnqualifiedType(T, R->getElementType())) 1686 return UnknownVal(); 1687 1688 const StringLiteral *Str = StrR->getStringLiteral(); 1689 SVal Idx = R->getIndex(); 1690 if (Optional<nonloc::ConcreteInt> CI = Idx.getAs<nonloc::ConcreteInt>()) { 1691 int64_t i = CI->getValue().getSExtValue(); 1692 // Abort on string underrun. This can be possible by arbitrary 1693 // clients of getBindingForElement(). 1694 if (i < 0) 1695 return UndefinedVal(); 1696 int64_t length = Str->getLength(); 1697 // Technically, only i == length is guaranteed to be null. 1698 // However, such overflows should be caught before reaching this point; 1699 // the only time such an access would be made is if a string literal was 1700 // used to initialize a larger array. 1701 char c = (i >= length) ? '\0' : Str->getCodeUnit(i); 1702 return svalBuilder.makeIntVal(c, T); 1703 } 1704 } else if (const VarRegion *VR = dyn_cast<VarRegion>(superR)) { 1705 // Check if the containing array has an initialized value that we can trust. 1706 // We can trust a const value or a value of a global initializer in main(). 1707 const VarDecl *VD = VR->getDecl(); 1708 if (VD->getType().isConstQualified() || 1709 R->getElementType().isConstQualified() || 1710 (B.isMainAnalysis() && VD->hasGlobalStorage())) { 1711 if (const Expr *Init = VD->getAnyInitializer()) { 1712 if (const auto *InitList = dyn_cast<InitListExpr>(Init)) { 1713 // The array index has to be known. 1714 if (auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) { 1715 int64_t i = CI->getValue().getSExtValue(); 1716 // If it is known that the index is out of bounds, we can return 1717 // an undefined value. 1718 if (i < 0) 1719 return UndefinedVal(); 1720 1721 if (auto CAT = Ctx.getAsConstantArrayType(VD->getType())) 1722 if (CAT->getSize().sle(i)) 1723 return UndefinedVal(); 1724 1725 // If there is a list, but no init, it must be zero. 1726 if (i >= InitList->getNumInits()) 1727 return svalBuilder.makeZeroVal(R->getElementType()); 1728 1729 if (const Expr *ElemInit = InitList->getInit(i)) 1730 if (Optional<SVal> V = svalBuilder.getConstantVal(ElemInit)) 1731 return *V; 1732 } 1733 } 1734 } 1735 } 1736 } 1737 1738 // Check for loads from a code text region. For such loads, just give up. 1739 if (isa<CodeTextRegion>(superR)) 1740 return UnknownVal(); 1741 1742 // Handle the case where we are indexing into a larger scalar object. 1743 // For example, this handles: 1744 // int x = ... 1745 // char *y = &x; 1746 // return *y; 1747 // FIXME: This is a hack, and doesn't do anything really intelligent yet. 1748 const RegionRawOffset &O = R->getAsArrayOffset(); 1749 1750 // If we cannot reason about the offset, return an unknown value. 1751 if (!O.getRegion()) 1752 return UnknownVal(); 1753 1754 if (const TypedValueRegion *baseR = 1755 dyn_cast_or_null<TypedValueRegion>(O.getRegion())) { 1756 QualType baseT = baseR->getValueType(); 1757 if (baseT->isScalarType()) { 1758 QualType elemT = R->getElementType(); 1759 if (elemT->isScalarType()) { 1760 if (Ctx.getTypeSizeInChars(baseT) >= Ctx.getTypeSizeInChars(elemT)) { 1761 if (const Optional<SVal> &V = B.getDirectBinding(superR)) { 1762 if (SymbolRef parentSym = V->getAsSymbol()) 1763 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1764 1765 if (V->isUnknownOrUndef()) 1766 return *V; 1767 // Other cases: give up. We are indexing into a larger object 1768 // that has some value, but we don't know how to handle that yet. 1769 return UnknownVal(); 1770 } 1771 } 1772 } 1773 } 1774 } 1775 return getBindingForFieldOrElementCommon(B, R, R->getElementType()); 1776} 1777 1778SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B, 1779 const FieldRegion* R) { 1780 1781 // Check if the region has a binding. 1782 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1783 return *V; 1784 1785 // Is the field declared constant and has an in-class initializer? 1786 const FieldDecl *FD = R->getDecl(); 1787 QualType Ty = FD->getType(); 1788 if (Ty.isConstQualified()) 1789 if (const Expr *Init = FD->getInClassInitializer()) 1790 if (Optional<SVal> V = svalBuilder.getConstantVal(Init)) 1791 return *V; 1792 1793 // If the containing record was initialized, try to get its constant value. 1794 const MemRegion* superR = R->getSuperRegion(); 1795 if (const auto *VR = dyn_cast<VarRegion>(superR)) { 1796 const VarDecl *VD = VR->getDecl(); 1797 QualType RecordVarTy = VD->getType(); 1798 unsigned Index = FD->getFieldIndex(); 1799 // Either the record variable or the field has an initializer that we can 1800 // trust. We trust initializers of constants and, additionally, respect 1801 // initializers of globals when analyzing main(). 1802 if (RecordVarTy.isConstQualified() || Ty.isConstQualified() || 1803 (B.isMainAnalysis() && VD->hasGlobalStorage())) 1804 if (const Expr *Init = VD->getAnyInitializer()) 1805 if (const auto *InitList = dyn_cast<InitListExpr>(Init)) { 1806 if (Index < InitList->getNumInits()) { 1807 if (const Expr *FieldInit = InitList->getInit(Index)) 1808 if (Optional<SVal> V = svalBuilder.getConstantVal(FieldInit)) 1809 return *V; 1810 } else { 1811 return svalBuilder.makeZeroVal(Ty); 1812 } 1813 } 1814 } 1815 1816 return getBindingForFieldOrElementCommon(B, R, Ty); 1817} 1818 1819Optional<SVal> 1820RegionStoreManager::getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 1821 const MemRegion *superR, 1822 const TypedValueRegion *R, 1823 QualType Ty) { 1824 1825 if (const Optional<SVal> &D = B.getDefaultBinding(superR)) { 1826 const SVal &val = D.getValue(); 1827 if (SymbolRef parentSym = val.getAsSymbol()) 1828 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1829 1830 if (val.isZeroConstant()) 1831 return svalBuilder.makeZeroVal(Ty); 1832 1833 if (val.isUnknownOrUndef()) 1834 return val; 1835 1836 // Lazy bindings are usually handled through getExistingLazyBinding(). 1837 // We should unify these two code paths at some point. 1838 if (val.getAs<nonloc::LazyCompoundVal>() || 1839 val.getAs<nonloc::CompoundVal>()) 1840 return val; 1841 1842 llvm_unreachable("Unknown default value"); 1843 } 1844 1845 return None; 1846} 1847 1848SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion, 1849 RegionBindingsRef LazyBinding) { 1850 SVal Result; 1851 if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion)) 1852 Result = getBindingForElement(LazyBinding, ER); 1853 else 1854 Result = getBindingForField(LazyBinding, 1855 cast<FieldRegion>(LazyBindingRegion)); 1856 1857 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1858 // default value for /part/ of an aggregate from a default value for the 1859 // /entire/ aggregate. The most common case of this is when struct Outer 1860 // has as its first member a struct Inner, which is copied in from a stack 1861 // variable. In this case, even if the Outer's default value is symbolic, 0, 1862 // or unknown, it gets overridden by the Inner's default value of undefined. 1863 // 1864 // This is a general problem -- if the Inner is zero-initialized, the Outer 1865 // will now look zero-initialized. The proper way to solve this is with a 1866 // new version of RegionStore that tracks the extent of a binding as well 1867 // as the offset. 1868 // 1869 // This hack only takes care of the undefined case because that can very 1870 // quickly result in a warning. 1871 if (Result.isUndef()) 1872 Result = UnknownVal(); 1873 1874 return Result; 1875} 1876 1877SVal 1878RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 1879 const TypedValueRegion *R, 1880 QualType Ty) { 1881 1882 // At this point we have already checked in either getBindingForElement or 1883 // getBindingForField if 'R' has a direct binding. 1884 1885 // Lazy binding? 1886 Store lazyBindingStore = nullptr; 1887 const SubRegion *lazyBindingRegion = nullptr; 1888 std::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R); 1889 if (lazyBindingRegion) 1890 return getLazyBinding(lazyBindingRegion, 1891 getRegionBindings(lazyBindingStore)); 1892 1893 // Record whether or not we see a symbolic index. That can completely 1894 // be out of scope of our lookup. 1895 bool hasSymbolicIndex = false; 1896 1897 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 1898 // default value for /part/ of an aggregate from a default value for the 1899 // /entire/ aggregate. The most common case of this is when struct Outer 1900 // has as its first member a struct Inner, which is copied in from a stack 1901 // variable. In this case, even if the Outer's default value is symbolic, 0, 1902 // or unknown, it gets overridden by the Inner's default value of undefined. 1903 // 1904 // This is a general problem -- if the Inner is zero-initialized, the Outer 1905 // will now look zero-initialized. The proper way to solve this is with a 1906 // new version of RegionStore that tracks the extent of a binding as well 1907 // as the offset. 1908 // 1909 // This hack only takes care of the undefined case because that can very 1910 // quickly result in a warning. 1911 bool hasPartialLazyBinding = false; 1912 1913 const SubRegion *SR = R; 1914 while (SR) { 1915 const MemRegion *Base = SR->getSuperRegion(); 1916 if (Optional<SVal> D = getBindingForDerivedDefaultValue(B, Base, R, Ty)) { 1917 if (D->getAs<nonloc::LazyCompoundVal>()) { 1918 hasPartialLazyBinding = true; 1919 break; 1920 } 1921 1922 return *D; 1923 } 1924 1925 if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) { 1926 NonLoc index = ER->getIndex(); 1927 if (!index.isConstant()) 1928 hasSymbolicIndex = true; 1929 } 1930 1931 // If our super region is a field or element itself, walk up the region 1932 // hierarchy to see if there is a default value installed in an ancestor. 1933 SR = dyn_cast<SubRegion>(Base); 1934 } 1935 1936 if (R->hasStackNonParametersStorage()) { 1937 if (isa<ElementRegion>(R)) { 1938 // Currently we don't reason specially about Clang-style vectors. Check 1939 // if superR is a vector and if so return Unknown. 1940 if (const TypedValueRegion *typedSuperR = 1941 dyn_cast<TypedValueRegion>(R->getSuperRegion())) { 1942 if (typedSuperR->getValueType()->isVectorType()) 1943 return UnknownVal(); 1944 } 1945 } 1946 1947 // FIXME: We also need to take ElementRegions with symbolic indexes into 1948 // account. This case handles both directly accessing an ElementRegion 1949 // with a symbolic offset, but also fields within an element with 1950 // a symbolic offset. 1951 if (hasSymbolicIndex) 1952 return UnknownVal(); 1953 1954 // Additionally allow introspection of a block's internal layout. 1955 if (!hasPartialLazyBinding && !isa<BlockDataRegion>(R->getBaseRegion())) 1956 return UndefinedVal(); 1957 } 1958 1959 // All other values are symbolic. 1960 return svalBuilder.getRegionValueSymbolVal(R); 1961} 1962 1963SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B, 1964 const ObjCIvarRegion* R) { 1965 // Check if the region has a binding. 1966 if (const Optional<SVal> &V = B.getDirectBinding(R)) 1967 return *V; 1968 1969 const MemRegion *superR = R->getSuperRegion(); 1970 1971 // Check if the super region has a default binding. 1972 if (const Optional<SVal> &V = B.getDefaultBinding(superR)) { 1973 if (SymbolRef parentSym = V->getAsSymbol()) 1974 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 1975 1976 // Other cases: give up. 1977 return UnknownVal(); 1978 } 1979 1980 return getBindingForLazySymbol(R); 1981} 1982 1983SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B, 1984 const VarRegion *R) { 1985 1986 // Check if the region has a binding. 1987 if (Optional<SVal> V = B.getDirectBinding(R)) 1988 return *V; 1989 1990 if (Optional<SVal> V = B.getDefaultBinding(R)) 1991 return *V; 1992 1993 // Lazily derive a value for the VarRegion. 1994 const VarDecl *VD = R->getDecl(); 1995 const MemSpaceRegion *MS = R->getMemorySpace(); 1996 1997 // Arguments are always symbolic. 1998 if (isa<StackArgumentsSpaceRegion>(MS)) 1999 return svalBuilder.getRegionValueSymbolVal(R); 2000 2001 // Is 'VD' declared constant? If so, retrieve the constant value. 2002 if (VD->getType().isConstQualified()) { 2003 if (const Expr *Init = VD->getAnyInitializer()) { 2004 if (Optional<SVal> V = svalBuilder.getConstantVal(Init)) 2005 return *V; 2006 2007 // If the variable is const qualified and has an initializer but 2008 // we couldn't evaluate initializer to a value, treat the value as 2009 // unknown. 2010 return UnknownVal(); 2011 } 2012 } 2013 2014 // This must come after the check for constants because closure-captured 2015 // constant variables may appear in UnknownSpaceRegion. 2016 if (isa<UnknownSpaceRegion>(MS)) 2017 return svalBuilder.getRegionValueSymbolVal(R); 2018 2019 if (isa<GlobalsSpaceRegion>(MS)) { 2020 QualType T = VD->getType(); 2021 2022 // If we're in main(), then global initializers have not become stale yet. 2023 if (B.isMainAnalysis()) 2024 if (const Expr *Init = VD->getAnyInitializer()) 2025 if (Optional<SVal> V = svalBuilder.getConstantVal(Init)) 2026 return *V; 2027 2028 // Function-scoped static variables are default-initialized to 0; if they 2029 // have an initializer, it would have been processed by now. 2030 // FIXME: This is only true when we're starting analysis from main(). 2031 // We're losing a lot of coverage here. 2032 if (isa<StaticGlobalSpaceRegion>(MS)) 2033 return svalBuilder.makeZeroVal(T); 2034 2035 if (Optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) { 2036 assert(!V->getAs<nonloc::LazyCompoundVal>()); 2037 return V.getValue(); 2038 } 2039 2040 return svalBuilder.getRegionValueSymbolVal(R); 2041 } 2042 2043 return UndefinedVal(); 2044} 2045 2046SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) { 2047 // All other values are symbolic. 2048 return svalBuilder.getRegionValueSymbolVal(R); 2049} 2050 2051const RegionStoreManager::SValListTy & 2052RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) { 2053 // First, check the cache. 2054 LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData()); 2055 if (I != LazyBindingsMap.end()) 2056 return I->second; 2057 2058 // If we don't have a list of values cached, start constructing it. 2059 SValListTy List; 2060 2061 const SubRegion *LazyR = LCV.getRegion(); 2062 RegionBindingsRef B = getRegionBindings(LCV.getStore()); 2063 2064 // If this region had /no/ bindings at the time, there are no interesting 2065 // values to return. 2066 const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion()); 2067 if (!Cluster) 2068 return (LazyBindingsMap[LCV.getCVData()] = std::move(List)); 2069 2070 SmallVector<BindingPair, 32> Bindings; 2071 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR, 2072 /*IncludeAllDefaultBindings=*/true); 2073 for (SmallVectorImpl<BindingPair>::const_iterator I = Bindings.begin(), 2074 E = Bindings.end(); 2075 I != E; ++I) { 2076 SVal V = I->second; 2077 if (V.isUnknownOrUndef() || V.isConstant()) 2078 continue; 2079 2080 if (Optional<nonloc::LazyCompoundVal> InnerLCV = 2081 V.getAs<nonloc::LazyCompoundVal>()) { 2082 const SValListTy &InnerList = getInterestingValues(*InnerLCV); 2083 List.insert(List.end(), InnerList.begin(), InnerList.end()); 2084 continue; 2085 } 2086 2087 List.push_back(V); 2088 } 2089 2090 return (LazyBindingsMap[LCV.getCVData()] = std::move(List)); 2091} 2092 2093NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B, 2094 const TypedValueRegion *R) { 2095 if (Optional<nonloc::LazyCompoundVal> V = 2096 getExistingLazyBinding(svalBuilder, B, R, false)) 2097 return *V; 2098 2099 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R); 2100} 2101 2102static bool isRecordEmpty(const RecordDecl *RD) { 2103 if (!RD->field_empty()) 2104 return false; 2105 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) 2106 return CRD->getNumBases() == 0; 2107 return true; 2108} 2109 2110SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B, 2111 const TypedValueRegion *R) { 2112 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl(); 2113 if (!RD->getDefinition() || isRecordEmpty(RD)) 2114 return UnknownVal(); 2115 2116 return createLazyBinding(B, R); 2117} 2118 2119SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B, 2120 const TypedValueRegion *R) { 2121 assert(Ctx.getAsConstantArrayType(R->getValueType()) && 2122 "Only constant array types can have compound bindings."); 2123 2124 return createLazyBinding(B, R); 2125} 2126 2127bool RegionStoreManager::includedInBindings(Store store, 2128 const MemRegion *region) const { 2129 RegionBindingsRef B = getRegionBindings(store); 2130 region = region->getBaseRegion(); 2131 2132 // Quick path: if the base is the head of a cluster, the region is live. 2133 if (B.lookup(region)) 2134 return true; 2135 2136 // Slow path: if the region is the VALUE of any binding, it is live. 2137 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) { 2138 const ClusterBindings &Cluster = RI.getData(); 2139 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 2140 CI != CE; ++CI) { 2141 const SVal &D = CI.getData(); 2142 if (const MemRegion *R = D.getAsRegion()) 2143 if (R->getBaseRegion() == region) 2144 return true; 2145 } 2146 } 2147 2148 return false; 2149} 2150 2151//===----------------------------------------------------------------------===// 2152// Binding values to regions. 2153//===----------------------------------------------------------------------===// 2154 2155StoreRef RegionStoreManager::killBinding(Store ST, Loc L) { 2156 if (Optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>()) 2157 if (const MemRegion* R = LV->getRegion()) 2158 return StoreRef(getRegionBindings(ST).removeBinding(R) 2159 .asImmutableMap() 2160 .getRootWithoutRetain(), 2161 *this); 2162 2163 return StoreRef(ST, *this); 2164} 2165 2166RegionBindingsRef 2167RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) { 2168 if (L.getAs<loc::ConcreteInt>()) 2169 return B; 2170 2171 // If we get here, the location should be a region. 2172 const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion(); 2173 2174 // Check if the region is a struct region. 2175 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) { 2176 QualType Ty = TR->getValueType(); 2177 if (Ty->isArrayType()) 2178 return bindArray(B, TR, V); 2179 if (Ty->isStructureOrClassType()) 2180 return bindStruct(B, TR, V); 2181 if (Ty->isVectorType()) 2182 return bindVector(B, TR, V); 2183 if (Ty->isUnionType()) 2184 return bindAggregate(B, TR, V); 2185 } 2186 2187 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) { 2188 // Binding directly to a symbolic region should be treated as binding 2189 // to element 0. 2190 QualType T = SR->getSymbol()->getType(); 2191 if (T->isAnyPointerType() || T->isReferenceType()) 2192 T = T->getPointeeType(); 2193 2194 R = GetElementZeroRegion(SR, T); 2195 } 2196 2197 assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) && 2198 "'this' pointer is not an l-value and is not assignable"); 2199 2200 // Clear out bindings that may overlap with this binding. 2201 RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R)); 2202 return NewB.addBinding(BindingKey::Make(R, BindingKey::Direct), V); 2203} 2204 2205RegionBindingsRef 2206RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B, 2207 const MemRegion *R, 2208 QualType T) { 2209 SVal V; 2210 2211 if (Loc::isLocType(T)) 2212 V = svalBuilder.makeNull(); 2213 else if (T->isIntegralOrEnumerationType()) 2214 V = svalBuilder.makeZeroVal(T); 2215 else if (T->isStructureOrClassType() || T->isArrayType()) { 2216 // Set the default value to a zero constant when it is a structure 2217 // or array. The type doesn't really matter. 2218 V = svalBuilder.makeZeroVal(Ctx.IntTy); 2219 } 2220 else { 2221 // We can't represent values of this type, but we still need to set a value 2222 // to record that the region has been initialized. 2223 // If this assertion ever fires, a new case should be added above -- we 2224 // should know how to default-initialize any value we can symbolicate. 2225 assert(!SymbolManager::canSymbolicate(T) && "This type is representable"); 2226 V = UnknownVal(); 2227 } 2228 2229 return B.addBinding(R, BindingKey::Default, V); 2230} 2231 2232RegionBindingsRef 2233RegionStoreManager::bindArray(RegionBindingsConstRef B, 2234 const TypedValueRegion* R, 2235 SVal Init) { 2236 2237 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType())); 2238 QualType ElementTy = AT->getElementType(); 2239 Optional<uint64_t> Size; 2240 2241 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT)) 2242 Size = CAT->getSize().getZExtValue(); 2243 2244 // Check if the init expr is a literal. If so, bind the rvalue instead. 2245 // FIXME: It's not responsibility of the Store to transform this lvalue 2246 // to rvalue. ExprEngine or maybe even CFG should do this before binding. 2247 if (Optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) { 2248 SVal V = getBinding(B.asStore(), *MRV, R->getValueType()); 2249 return bindAggregate(B, R, V); 2250 } 2251 2252 // Handle lazy compound values. 2253 if (Init.getAs<nonloc::LazyCompoundVal>()) 2254 return bindAggregate(B, R, Init); 2255 2256 if (Init.isUnknown()) 2257 return bindAggregate(B, R, UnknownVal()); 2258 2259 // Remaining case: explicit compound values. 2260 const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>(); 2261 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2262 uint64_t i = 0; 2263 2264 RegionBindingsRef NewB(B); 2265 2266 for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) { 2267 // The init list might be shorter than the array length. 2268 if (VI == VE) 2269 break; 2270 2271 const NonLoc &Idx = svalBuilder.makeArrayIndex(i); 2272 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx); 2273 2274 if (ElementTy->isStructureOrClassType()) 2275 NewB = bindStruct(NewB, ER, *VI); 2276 else if (ElementTy->isArrayType()) 2277 NewB = bindArray(NewB, ER, *VI); 2278 else 2279 NewB = bind(NewB, loc::MemRegionVal(ER), *VI); 2280 } 2281 2282 // If the init list is shorter than the array length (or the array has 2283 // variable length), set the array default value. Values that are already set 2284 // are not overwritten. 2285 if (!Size.hasValue() || i < Size.getValue()) 2286 NewB = setImplicitDefaultValue(NewB, R, ElementTy); 2287 2288 return NewB; 2289} 2290 2291RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B, 2292 const TypedValueRegion* R, 2293 SVal V) { 2294 QualType T = R->getValueType(); 2295 const VectorType *VT = T->castAs<VectorType>(); // Use castAs for typedefs. 2296 2297 // Handle lazy compound values and symbolic values. 2298 if (V.getAs<nonloc::LazyCompoundVal>() || V.getAs<nonloc::SymbolVal>()) 2299 return bindAggregate(B, R, V); 2300 2301 // We may get non-CompoundVal accidentally due to imprecise cast logic or 2302 // that we are binding symbolic struct value. Kill the field values, and if 2303 // the value is symbolic go and bind it as a "default" binding. 2304 if (!V.getAs<nonloc::CompoundVal>()) { 2305 return bindAggregate(B, R, UnknownVal()); 2306 } 2307 2308 QualType ElemType = VT->getElementType(); 2309 nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>(); 2310 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2311 unsigned index = 0, numElements = VT->getNumElements(); 2312 RegionBindingsRef NewB(B); 2313 2314 for ( ; index != numElements ; ++index) { 2315 if (VI == VE) 2316 break; 2317 2318 NonLoc Idx = svalBuilder.makeArrayIndex(index); 2319 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx); 2320 2321 if (ElemType->isArrayType()) 2322 NewB = bindArray(NewB, ER, *VI); 2323 else if (ElemType->isStructureOrClassType()) 2324 NewB = bindStruct(NewB, ER, *VI); 2325 else 2326 NewB = bind(NewB, loc::MemRegionVal(ER), *VI); 2327 } 2328 return NewB; 2329} 2330 2331Optional<RegionBindingsRef> 2332RegionStoreManager::tryBindSmallStruct(RegionBindingsConstRef B, 2333 const TypedValueRegion *R, 2334 const RecordDecl *RD, 2335 nonloc::LazyCompoundVal LCV) { 2336 FieldVector Fields; 2337 2338 if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(RD)) 2339 if (Class->getNumBases() != 0 || Class->getNumVBases() != 0) 2340 return None; 2341 2342 for (const auto *FD : RD->fields()) { 2343 if (FD->isUnnamedBitfield()) 2344 continue; 2345 2346 // If there are too many fields, or if any of the fields are aggregates, 2347 // just use the LCV as a default binding. 2348 if (Fields.size() == SmallStructLimit) 2349 return None; 2350 2351 QualType Ty = FD->getType(); 2352 if (!(Ty->isScalarType() || Ty->isReferenceType())) 2353 return None; 2354 2355 Fields.push_back(FD); 2356 } 2357 2358 RegionBindingsRef NewB = B; 2359 2360 for (FieldVector::iterator I = Fields.begin(), E = Fields.end(); I != E; ++I){ 2361 const FieldRegion *SourceFR = MRMgr.getFieldRegion(*I, LCV.getRegion()); 2362 SVal V = getBindingForField(getRegionBindings(LCV.getStore()), SourceFR); 2363 2364 const FieldRegion *DestFR = MRMgr.getFieldRegion(*I, R); 2365 NewB = bind(NewB, loc::MemRegionVal(DestFR), V); 2366 } 2367 2368 return NewB; 2369} 2370 2371RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B, 2372 const TypedValueRegion* R, 2373 SVal V) { 2374 if (!Features.supportsFields()) 2375 return B; 2376 2377 QualType T = R->getValueType(); 2378 assert(T->isStructureOrClassType()); 2379 2380 const RecordType* RT = T->castAs<RecordType>(); 2381 const RecordDecl *RD = RT->getDecl(); 2382 2383 if (!RD->isCompleteDefinition()) 2384 return B; 2385 2386 // Handle lazy compound values and symbolic values. 2387 if (Optional<nonloc::LazyCompoundVal> LCV = 2388 V.getAs<nonloc::LazyCompoundVal>()) { 2389 if (Optional<RegionBindingsRef> NewB = tryBindSmallStruct(B, R, RD, *LCV)) 2390 return *NewB; 2391 return bindAggregate(B, R, V); 2392 } 2393 if (V.getAs<nonloc::SymbolVal>()) 2394 return bindAggregate(B, R, V); 2395 2396 // We may get non-CompoundVal accidentally due to imprecise cast logic or 2397 // that we are binding symbolic struct value. Kill the field values, and if 2398 // the value is symbolic go and bind it as a "default" binding. 2399 if (V.isUnknown() || !V.getAs<nonloc::CompoundVal>()) 2400 return bindAggregate(B, R, UnknownVal()); 2401 2402 // The raw CompoundVal is essentially a symbolic InitListExpr: an (immutable) 2403 // list of other values. It appears pretty much only when there's an actual 2404 // initializer list expression in the program, and the analyzer tries to 2405 // unwrap it as soon as possible. 2406 // This code is where such unwrap happens: when the compound value is put into 2407 // the object that it was supposed to initialize (it's an *initializer* list, 2408 // after all), instead of binding the whole value to the whole object, we bind 2409 // sub-values to sub-objects. Sub-values may themselves be compound values, 2410 // and in this case the procedure becomes recursive. 2411 // FIXME: The annoying part about compound values is that they don't carry 2412 // any sort of information about which value corresponds to which sub-object. 2413 // It's simply a list of values in the middle of nowhere; we expect to match 2414 // them to sub-objects, essentially, "by index": first value binds to 2415 // the first field, second value binds to the second field, etc. 2416 // It would have been much safer to organize non-lazy compound values as 2417 // a mapping from fields/bases to values. 2418 const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>(); 2419 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2420 2421 RegionBindingsRef NewB(B); 2422 2423 // In C++17 aggregates may have base classes, handle those as well. 2424 // They appear before fields in the initializer list / compound value. 2425 if (const auto *CRD = dyn_cast<CXXRecordDecl>(RD)) { 2426 // If the object was constructed with a constructor, its value is a 2427 // LazyCompoundVal. If it's a raw CompoundVal, it means that we're 2428 // performing aggregate initialization. The only exception from this 2429 // rule is sending an Objective-C++ message that returns a C++ object 2430 // to a nil receiver; in this case the semantics is to return a 2431 // zero-initialized object even if it's a C++ object that doesn't have 2432 // this sort of constructor; the CompoundVal is empty in this case. 2433 assert((CRD->isAggregate() || (Ctx.getLangOpts().ObjC && VI == VE)) && 2434 "Non-aggregates are constructed with a constructor!"); 2435 2436 for (const auto &B : CRD->bases()) { 2437 // (Multiple inheritance is fine though.) 2438 assert(!B.isVirtual() && "Aggregates cannot have virtual base classes!"); 2439 2440 if (VI == VE) 2441 break; 2442 2443 QualType BTy = B.getType(); 2444 assert(BTy->isStructureOrClassType() && "Base classes must be classes!"); 2445 2446 const CXXRecordDecl *BRD = BTy->getAsCXXRecordDecl(); 2447 assert(BRD && "Base classes must be C++ classes!"); 2448 2449 const CXXBaseObjectRegion *BR = 2450 MRMgr.getCXXBaseObjectRegion(BRD, R, /*IsVirtual=*/false); 2451 2452 NewB = bindStruct(NewB, BR, *VI); 2453 2454 ++VI; 2455 } 2456 } 2457 2458 RecordDecl::field_iterator FI, FE; 2459 2460 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) { 2461 2462 if (VI == VE) 2463 break; 2464 2465 // Skip any unnamed bitfields to stay in sync with the initializers. 2466 if (FI->isUnnamedBitfield()) 2467 continue; 2468 2469 QualType FTy = FI->getType(); 2470 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R); 2471 2472 if (FTy->isArrayType()) 2473 NewB = bindArray(NewB, FR, *VI); 2474 else if (FTy->isStructureOrClassType()) 2475 NewB = bindStruct(NewB, FR, *VI); 2476 else 2477 NewB = bind(NewB, loc::MemRegionVal(FR), *VI); 2478 ++VI; 2479 } 2480 2481 // There may be fewer values in the initialize list than the fields of struct. 2482 if (FI != FE) { 2483 NewB = NewB.addBinding(R, BindingKey::Default, 2484 svalBuilder.makeIntVal(0, false)); 2485 } 2486 2487 return NewB; 2488} 2489 2490RegionBindingsRef 2491RegionStoreManager::bindAggregate(RegionBindingsConstRef B, 2492 const TypedRegion *R, 2493 SVal Val) { 2494 // Remove the old bindings, using 'R' as the root of all regions 2495 // we will invalidate. Then add the new binding. 2496 return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val); 2497} 2498 2499//===----------------------------------------------------------------------===// 2500// State pruning. 2501//===----------------------------------------------------------------------===// 2502 2503namespace { 2504class RemoveDeadBindingsWorker 2505 : public ClusterAnalysis<RemoveDeadBindingsWorker> { 2506 SmallVector<const SymbolicRegion *, 12> Postponed; 2507 SymbolReaper &SymReaper; 2508 const StackFrameContext *CurrentLCtx; 2509 2510public: 2511 RemoveDeadBindingsWorker(RegionStoreManager &rm, 2512 ProgramStateManager &stateMgr, 2513 RegionBindingsRef b, SymbolReaper &symReaper, 2514 const StackFrameContext *LCtx) 2515 : ClusterAnalysis<RemoveDeadBindingsWorker>(rm, stateMgr, b), 2516 SymReaper(symReaper), CurrentLCtx(LCtx) {} 2517 2518 // Called by ClusterAnalysis. 2519 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C); 2520 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C); 2521 using ClusterAnalysis<RemoveDeadBindingsWorker>::VisitCluster; 2522 2523 using ClusterAnalysis::AddToWorkList; 2524 2525 bool AddToWorkList(const MemRegion *R); 2526 2527 bool UpdatePostponed(); 2528 void VisitBinding(SVal V); 2529}; 2530} 2531 2532bool RemoveDeadBindingsWorker::AddToWorkList(const MemRegion *R) { 2533 const MemRegion *BaseR = R->getBaseRegion(); 2534 return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR)); 2535} 2536 2537void RemoveDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR, 2538 const ClusterBindings &C) { 2539 2540 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) { 2541 if (SymReaper.isLive(VR)) 2542 AddToWorkList(baseR, &C); 2543 2544 return; 2545 } 2546 2547 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 2548 if (SymReaper.isLive(SR->getSymbol())) 2549 AddToWorkList(SR, &C); 2550 else 2551 Postponed.push_back(SR); 2552 2553 return; 2554 } 2555 2556 if (isa<NonStaticGlobalSpaceRegion>(baseR)) { 2557 AddToWorkList(baseR, &C); 2558 return; 2559 } 2560 2561 // CXXThisRegion in the current or parent location context is live. 2562 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) { 2563 const auto *StackReg = 2564 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion()); 2565 const StackFrameContext *RegCtx = StackReg->getStackFrame(); 2566 if (CurrentLCtx && 2567 (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))) 2568 AddToWorkList(TR, &C); 2569 } 2570} 2571 2572void RemoveDeadBindingsWorker::VisitCluster(const MemRegion *baseR, 2573 const ClusterBindings *C) { 2574 if (!C) 2575 return; 2576 2577 // Mark the symbol for any SymbolicRegion with live bindings as live itself. 2578 // This means we should continue to track that symbol. 2579 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR)) 2580 SymReaper.markLive(SymR->getSymbol()); 2581 2582 for (ClusterBindings::iterator I = C->begin(), E = C->end(); I != E; ++I) { 2583 // Element index of a binding key is live. 2584 SymReaper.markElementIndicesLive(I.getKey().getRegion()); 2585 2586 VisitBinding(I.getData()); 2587 } 2588} 2589 2590void RemoveDeadBindingsWorker::VisitBinding(SVal V) { 2591 // Is it a LazyCompoundVal? All referenced regions are live as well. 2592 if (Optional<nonloc::LazyCompoundVal> LCS = 2593 V.getAs<nonloc::LazyCompoundVal>()) { 2594 2595 const RegionStoreManager::SValListTy &Vals = RM.getInterestingValues(*LCS); 2596 2597 for (RegionStoreManager::SValListTy::const_iterator I = Vals.begin(), 2598 E = Vals.end(); 2599 I != E; ++I) 2600 VisitBinding(*I); 2601 2602 return; 2603 } 2604 2605 // If V is a region, then add it to the worklist. 2606 if (const MemRegion *R = V.getAsRegion()) { 2607 AddToWorkList(R); 2608 SymReaper.markLive(R); 2609 2610 // All regions captured by a block are also live. 2611 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) { 2612 BlockDataRegion::referenced_vars_iterator I = BR->referenced_vars_begin(), 2613 E = BR->referenced_vars_end(); 2614 for ( ; I != E; ++I) 2615 AddToWorkList(I.getCapturedRegion()); 2616 } 2617 } 2618 2619 2620 // Update the set of live symbols. 2621 for (auto SI = V.symbol_begin(), SE = V.symbol_end(); SI!=SE; ++SI) 2622 SymReaper.markLive(*SI); 2623} 2624 2625bool RemoveDeadBindingsWorker::UpdatePostponed() { 2626 // See if any postponed SymbolicRegions are actually live now, after 2627 // having done a scan. 2628 bool Changed = false; 2629 2630 for (auto I = Postponed.begin(), E = Postponed.end(); I != E; ++I) { 2631 if (const SymbolicRegion *SR = *I) { 2632 if (SymReaper.isLive(SR->getSymbol())) { 2633 Changed |= AddToWorkList(SR); 2634 *I = nullptr; 2635 } 2636 } 2637 } 2638 2639 return Changed; 2640} 2641 2642StoreRef RegionStoreManager::removeDeadBindings(Store store, 2643 const StackFrameContext *LCtx, 2644 SymbolReaper& SymReaper) { 2645 RegionBindingsRef B = getRegionBindings(store); 2646 RemoveDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx); 2647 W.GenerateClusters(); 2648 2649 // Enqueue the region roots onto the worklist. 2650 for (SymbolReaper::region_iterator I = SymReaper.region_begin(), 2651 E = SymReaper.region_end(); I != E; ++I) { 2652 W.AddToWorkList(*I); 2653 } 2654 2655 do W.RunWorkList(); while (W.UpdatePostponed()); 2656 2657 // We have now scanned the store, marking reachable regions and symbols 2658 // as live. We now remove all the regions that are dead from the store 2659 // as well as update DSymbols with the set symbols that are now dead. 2660 for (RegionBindingsRef::iterator I = B.begin(), E = B.end(); I != E; ++I) { 2661 const MemRegion *Base = I.getKey(); 2662 2663 // If the cluster has been visited, we know the region has been marked. 2664 // Otherwise, remove the dead entry. 2665 if (!W.isVisited(Base)) 2666 B = B.remove(Base); 2667 } 2668 2669 return StoreRef(B.asStore(), *this); 2670} 2671 2672//===----------------------------------------------------------------------===// 2673// Utility methods. 2674//===----------------------------------------------------------------------===// 2675 2676void RegionStoreManager::printJson(raw_ostream &Out, Store S, const char *NL, 2677 unsigned int Space, bool IsDot) const { 2678 RegionBindingsRef Bindings = getRegionBindings(S); 2679 2680 Indent(Out, Space, IsDot) << "\"store\": "; 2681 2682 if (Bindings.isEmpty()) { 2683 Out << "null," << NL; 2684 return; 2685 } 2686 2687 Out << "{ \"pointer\": \"" << Bindings.asStore() << "\", \"items\": [" << NL; 2688 Bindings.printJson(Out, NL, Space + 1, IsDot); 2689 Indent(Out, Space, IsDot) << "]}," << NL; 2690} 2691