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/ExprEngine.h" 27#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 28#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" 29#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 30#include "llvm/ADT/ImmutableMap.h" 31#include "llvm/ADT/STLExtras.h" 32#include "llvm/Support/raw_ostream.h" 33#include <optional> 34#include <utility> 35 36using namespace clang; 37using namespace ento; 38 39//===----------------------------------------------------------------------===// 40// Representation of binding keys. 41//===----------------------------------------------------------------------===// 42 43namespace { 44class BindingKey { 45public: 46 enum Kind { Default = 0x0, Direct = 0x1 }; 47private: 48 enum { Symbolic = 0x2 }; 49 50 llvm::PointerIntPair<const MemRegion *, 2> P; 51 uint64_t Data; 52 53 /// Create a key for a binding to region \p r, which has a symbolic offset 54 /// from region \p Base. 55 explicit BindingKey(const SubRegion *r, const SubRegion *Base, Kind k) 56 : P(r, k | Symbolic), Data(reinterpret_cast<uintptr_t>(Base)) { 57 assert(r && Base && "Must have known regions."); 58 assert(getConcreteOffsetRegion() == Base && "Failed to store base region"); 59 } 60 61 /// Create a key for a binding at \p offset from base region \p r. 62 explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k) 63 : P(r, k), Data(offset) { 64 assert(r && "Must have known regions."); 65 assert(getOffset() == offset && "Failed to store offset"); 66 assert((r == r->getBaseRegion() || 67 isa<ObjCIvarRegion, CXXDerivedObjectRegion>(r)) && 68 "Not a base"); 69 } 70public: 71 72 bool isDirect() const { return P.getInt() & Direct; } 73 bool hasSymbolicOffset() const { return P.getInt() & Symbolic; } 74 75 const MemRegion *getRegion() const { return P.getPointer(); } 76 uint64_t getOffset() const { 77 assert(!hasSymbolicOffset()); 78 return Data; 79 } 80 81 const SubRegion *getConcreteOffsetRegion() const { 82 assert(hasSymbolicOffset()); 83 return reinterpret_cast<const SubRegion *>(static_cast<uintptr_t>(Data)); 84 } 85 86 const MemRegion *getBaseRegion() const { 87 if (hasSymbolicOffset()) 88 return getConcreteOffsetRegion()->getBaseRegion(); 89 return getRegion()->getBaseRegion(); 90 } 91 92 void Profile(llvm::FoldingSetNodeID& ID) const { 93 ID.AddPointer(P.getOpaqueValue()); 94 ID.AddInteger(Data); 95 } 96 97 static BindingKey Make(const MemRegion *R, Kind k); 98 99 bool operator<(const BindingKey &X) const { 100 if (P.getOpaqueValue() < X.P.getOpaqueValue()) 101 return true; 102 if (P.getOpaqueValue() > X.P.getOpaqueValue()) 103 return false; 104 return Data < X.Data; 105 } 106 107 bool operator==(const BindingKey &X) const { 108 return P.getOpaqueValue() == X.P.getOpaqueValue() && 109 Data == X.Data; 110 } 111 112 LLVM_DUMP_METHOD void dump() const; 113}; 114} // end anonymous namespace 115 116BindingKey BindingKey::Make(const MemRegion *R, Kind k) { 117 const RegionOffset &RO = R->getAsOffset(); 118 if (RO.hasSymbolicOffset()) 119 return BindingKey(cast<SubRegion>(R), cast<SubRegion>(RO.getRegion()), k); 120 121 return BindingKey(RO.getRegion(), RO.getOffset(), k); 122} 123 124namespace llvm { 125static inline raw_ostream &operator<<(raw_ostream &Out, BindingKey K) { 126 Out << "\"kind\": \"" << (K.isDirect() ? "Direct" : "Default") 127 << "\", \"offset\": "; 128 129 if (!K.hasSymbolicOffset()) 130 Out << K.getOffset(); 131 else 132 Out << "null"; 133 134 return Out; 135} 136 137} // namespace llvm 138 139#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 140void BindingKey::dump() const { llvm::errs() << *this; } 141#endif 142 143//===----------------------------------------------------------------------===// 144// Actual Store type. 145//===----------------------------------------------------------------------===// 146 147typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings; 148typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef; 149typedef std::pair<BindingKey, SVal> BindingPair; 150 151typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings> 152 RegionBindings; 153 154namespace { 155class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *, 156 ClusterBindings> { 157 ClusterBindings::Factory *CBFactory; 158 159 // This flag indicates whether the current bindings are within the analysis 160 // that has started from main(). It affects how we perform loads from 161 // global variables that have initializers: if we have observed the 162 // program execution from the start and we know that these variables 163 // have not been overwritten yet, we can be sure that their initializers 164 // are still relevant. This flag never gets changed when the bindings are 165 // updated, so it could potentially be moved into RegionStoreManager 166 // (as if it's the same bindings but a different loading procedure) 167 // however that would have made the manager needlessly stateful. 168 bool IsMainAnalysis; 169 170public: 171 typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings> 172 ParentTy; 173 174 RegionBindingsRef(ClusterBindings::Factory &CBFactory, 175 const RegionBindings::TreeTy *T, 176 RegionBindings::TreeTy::Factory *F, 177 bool IsMainAnalysis) 178 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(T, F), 179 CBFactory(&CBFactory), IsMainAnalysis(IsMainAnalysis) {} 180 181 RegionBindingsRef(const ParentTy &P, 182 ClusterBindings::Factory &CBFactory, 183 bool IsMainAnalysis) 184 : llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>(P), 185 CBFactory(&CBFactory), IsMainAnalysis(IsMainAnalysis) {} 186 187 RegionBindingsRef add(key_type_ref K, data_type_ref D) const { 188 return RegionBindingsRef(static_cast<const ParentTy *>(this)->add(K, D), 189 *CBFactory, IsMainAnalysis); 190 } 191 192 RegionBindingsRef remove(key_type_ref K) const { 193 return RegionBindingsRef(static_cast<const ParentTy *>(this)->remove(K), 194 *CBFactory, IsMainAnalysis); 195 } 196 197 RegionBindingsRef addBinding(BindingKey K, SVal V) const; 198 199 RegionBindingsRef addBinding(const MemRegion *R, 200 BindingKey::Kind k, SVal V) const; 201 202 const SVal *lookup(BindingKey K) const; 203 const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const; 204 using llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>::lookup; 205 206 RegionBindingsRef removeBinding(BindingKey K); 207 208 RegionBindingsRef removeBinding(const MemRegion *R, 209 BindingKey::Kind k); 210 211 RegionBindingsRef removeBinding(const MemRegion *R) { 212 return removeBinding(R, BindingKey::Direct). 213 removeBinding(R, BindingKey::Default); 214 } 215 216 std::optional<SVal> getDirectBinding(const MemRegion *R) const; 217 218 /// getDefaultBinding - Returns an SVal* representing an optional default 219 /// binding associated with a region and its subregions. 220 std::optional<SVal> getDefaultBinding(const MemRegion *R) const; 221 222 /// Return the internal tree as a Store. 223 Store asStore() const { 224 llvm::PointerIntPair<Store, 1, bool> Ptr = { 225 asImmutableMap().getRootWithoutRetain(), IsMainAnalysis}; 226 return reinterpret_cast<Store>(Ptr.getOpaqueValue()); 227 } 228 229 bool isMainAnalysis() const { 230 return IsMainAnalysis; 231 } 232 233 void printJson(raw_ostream &Out, const char *NL = "\n", 234 unsigned int Space = 0, bool IsDot = false) const { 235 for (iterator I = begin(), E = end(); I != E; ++I) { 236 // TODO: We might need a .printJson for I.getKey() as well. 237 Indent(Out, Space, IsDot) 238 << "{ \"cluster\": \"" << I.getKey() << "\", \"pointer\": \"" 239 << (const void *)I.getKey() << "\", \"items\": [" << NL; 240 241 ++Space; 242 const ClusterBindings &CB = I.getData(); 243 for (ClusterBindings::iterator CI = CB.begin(), CE = CB.end(); CI != CE; 244 ++CI) { 245 Indent(Out, Space, IsDot) << "{ " << CI.getKey() << ", \"value\": "; 246 CI.getData().printJson(Out, /*AddQuotes=*/true); 247 Out << " }"; 248 if (std::next(CI) != CE) 249 Out << ','; 250 Out << NL; 251 } 252 253 --Space; 254 Indent(Out, Space, IsDot) << "]}"; 255 if (std::next(I) != E) 256 Out << ','; 257 Out << NL; 258 } 259 } 260 261 LLVM_DUMP_METHOD void dump() const { printJson(llvm::errs()); } 262}; 263} // end anonymous namespace 264 265typedef const RegionBindingsRef& RegionBindingsConstRef; 266 267std::optional<SVal> 268RegionBindingsRef::getDirectBinding(const MemRegion *R) const { 269 const SVal *V = lookup(R, BindingKey::Direct); 270 return V ? std::optional<SVal>(*V) : std::nullopt; 271} 272 273std::optional<SVal> 274RegionBindingsRef::getDefaultBinding(const MemRegion *R) const { 275 const SVal *V = lookup(R, BindingKey::Default); 276 return V ? std::optional<SVal>(*V) : std::nullopt; 277} 278 279RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const { 280 const MemRegion *Base = K.getBaseRegion(); 281 282 const ClusterBindings *ExistingCluster = lookup(Base); 283 ClusterBindings Cluster = 284 (ExistingCluster ? *ExistingCluster : CBFactory->getEmptyMap()); 285 286 ClusterBindings NewCluster = CBFactory->add(Cluster, K, V); 287 return add(Base, NewCluster); 288} 289 290 291RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R, 292 BindingKey::Kind k, 293 SVal V) const { 294 return addBinding(BindingKey::Make(R, k), V); 295} 296 297const SVal *RegionBindingsRef::lookup(BindingKey K) const { 298 const ClusterBindings *Cluster = lookup(K.getBaseRegion()); 299 if (!Cluster) 300 return nullptr; 301 return Cluster->lookup(K); 302} 303 304const SVal *RegionBindingsRef::lookup(const MemRegion *R, 305 BindingKey::Kind k) const { 306 return lookup(BindingKey::Make(R, k)); 307} 308 309RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) { 310 const MemRegion *Base = K.getBaseRegion(); 311 const ClusterBindings *Cluster = lookup(Base); 312 if (!Cluster) 313 return *this; 314 315 ClusterBindings NewCluster = CBFactory->remove(*Cluster, K); 316 if (NewCluster.isEmpty()) 317 return remove(Base); 318 return add(Base, NewCluster); 319} 320 321RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R, 322 BindingKey::Kind k){ 323 return removeBinding(BindingKey::Make(R, k)); 324} 325 326//===----------------------------------------------------------------------===// 327// Main RegionStore logic. 328//===----------------------------------------------------------------------===// 329 330namespace { 331class InvalidateRegionsWorker; 332 333class RegionStoreManager : public StoreManager { 334public: 335 RegionBindings::Factory RBFactory; 336 mutable ClusterBindings::Factory CBFactory; 337 338 typedef std::vector<SVal> SValListTy; 339private: 340 typedef llvm::DenseMap<const LazyCompoundValData *, 341 SValListTy> LazyBindingsMapTy; 342 LazyBindingsMapTy LazyBindingsMap; 343 344 /// The largest number of fields a struct can have and still be 345 /// considered "small". 346 /// 347 /// This is currently used to decide whether or not it is worth "forcing" a 348 /// LazyCompoundVal on bind. 349 /// 350 /// This is controlled by 'region-store-small-struct-limit' option. 351 /// To disable all small-struct-dependent behavior, set the option to "0". 352 unsigned SmallStructLimit; 353 354 /// The largest number of element an array can have and still be 355 /// considered "small". 356 /// 357 /// This is currently used to decide whether or not it is worth "forcing" a 358 /// LazyCompoundVal on bind. 359 /// 360 /// This is controlled by 'region-store-small-struct-limit' option. 361 /// To disable all small-struct-dependent behavior, set the option to "0". 362 unsigned SmallArrayLimit; 363 364 /// A helper used to populate the work list with the given set of 365 /// regions. 366 void populateWorkList(InvalidateRegionsWorker &W, 367 ArrayRef<SVal> Values, 368 InvalidatedRegions *TopLevelRegions); 369 370public: 371 RegionStoreManager(ProgramStateManager &mgr) 372 : StoreManager(mgr), RBFactory(mgr.getAllocator()), 373 CBFactory(mgr.getAllocator()), SmallStructLimit(0), SmallArrayLimit(0) { 374 ExprEngine &Eng = StateMgr.getOwningEngine(); 375 AnalyzerOptions &Options = Eng.getAnalysisManager().options; 376 SmallStructLimit = Options.RegionStoreSmallStructLimit; 377 SmallArrayLimit = Options.RegionStoreSmallArrayLimit; 378 } 379 380 /// setImplicitDefaultValue - Set the default binding for the provided 381 /// MemRegion to the value implicitly defined for compound literals when 382 /// the value is not specified. 383 RegionBindingsRef setImplicitDefaultValue(RegionBindingsConstRef B, 384 const MemRegion *R, QualType T); 385 386 /// ArrayToPointer - Emulates the "decay" of an array to a pointer 387 /// type. 'Array' represents the lvalue of the array being decayed 388 /// to a pointer, and the returned SVal represents the decayed 389 /// version of that lvalue (i.e., a pointer to the first element of 390 /// the array). This is called by ExprEngine when evaluating 391 /// casts from arrays to pointers. 392 SVal ArrayToPointer(Loc Array, QualType ElementTy) override; 393 394 /// Creates the Store that correctly represents memory contents before 395 /// the beginning of the analysis of the given top-level stack frame. 396 StoreRef getInitialStore(const LocationContext *InitLoc) override { 397 bool IsMainAnalysis = false; 398 if (const auto *FD = dyn_cast<FunctionDecl>(InitLoc->getDecl())) 399 IsMainAnalysis = FD->isMain() && !Ctx.getLangOpts().CPlusPlus; 400 return StoreRef(RegionBindingsRef( 401 RegionBindingsRef::ParentTy(RBFactory.getEmptyMap(), RBFactory), 402 CBFactory, IsMainAnalysis).asStore(), *this); 403 } 404 405 //===-------------------------------------------------------------------===// 406 // Binding values to regions. 407 //===-------------------------------------------------------------------===// 408 RegionBindingsRef invalidateGlobalRegion(MemRegion::Kind K, 409 const Expr *Ex, 410 unsigned Count, 411 const LocationContext *LCtx, 412 RegionBindingsRef B, 413 InvalidatedRegions *Invalidated); 414 415 StoreRef invalidateRegions(Store store, 416 ArrayRef<SVal> Values, 417 const Expr *E, unsigned Count, 418 const LocationContext *LCtx, 419 const CallEvent *Call, 420 InvalidatedSymbols &IS, 421 RegionAndSymbolInvalidationTraits &ITraits, 422 InvalidatedRegions *Invalidated, 423 InvalidatedRegions *InvalidatedTopLevel) override; 424 425 bool scanReachableSymbols(Store S, const MemRegion *R, 426 ScanReachableSymbols &Callbacks) override; 427 428 RegionBindingsRef removeSubRegionBindings(RegionBindingsConstRef B, 429 const SubRegion *R); 430 std::optional<SVal> 431 getConstantValFromConstArrayInitializer(RegionBindingsConstRef B, 432 const ElementRegion *R); 433 std::optional<SVal> 434 getSValFromInitListExpr(const InitListExpr *ILE, 435 const SmallVector<uint64_t, 2> &ConcreteOffsets, 436 QualType ElemT); 437 SVal getSValFromStringLiteral(const StringLiteral *SL, uint64_t Offset, 438 QualType ElemT); 439 440public: // Part of public interface to class. 441 442 StoreRef Bind(Store store, Loc LV, SVal V) override { 443 return StoreRef(bind(getRegionBindings(store), LV, V).asStore(), *this); 444 } 445 446 RegionBindingsRef bind(RegionBindingsConstRef B, Loc LV, SVal V); 447 448 // BindDefaultInitial is only used to initialize a region with 449 // a default value. 450 StoreRef BindDefaultInitial(Store store, const MemRegion *R, 451 SVal V) override { 452 RegionBindingsRef B = getRegionBindings(store); 453 // Use other APIs when you have to wipe the region that was initialized 454 // earlier. 455 assert(!(B.getDefaultBinding(R) || B.getDirectBinding(R)) && 456 "Double initialization!"); 457 B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V); 458 return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this); 459 } 460 461 // BindDefaultZero is used for zeroing constructors that may accidentally 462 // overwrite existing bindings. 463 StoreRef BindDefaultZero(Store store, const MemRegion *R) override { 464 // FIXME: The offsets of empty bases can be tricky because of 465 // of the so called "empty base class optimization". 466 // If a base class has been optimized out 467 // we should not try to create a binding, otherwise we should. 468 // Unfortunately, at the moment ASTRecordLayout doesn't expose 469 // the actual sizes of the empty bases 470 // and trying to infer them from offsets/alignments 471 // seems to be error-prone and non-trivial because of the trailing padding. 472 // As a temporary mitigation we don't create bindings for empty bases. 473 if (const auto *BR = dyn_cast<CXXBaseObjectRegion>(R)) 474 if (BR->getDecl()->isEmpty()) 475 return StoreRef(store, *this); 476 477 RegionBindingsRef B = getRegionBindings(store); 478 SVal V = svalBuilder.makeZeroVal(Ctx.CharTy); 479 B = removeSubRegionBindings(B, cast<SubRegion>(R)); 480 B = B.addBinding(BindingKey::Make(R, BindingKey::Default), V); 481 return StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this); 482 } 483 484 /// Attempt to extract the fields of \p LCV and bind them to the struct region 485 /// \p R. 486 /// 487 /// This path is used when it seems advantageous to "force" loading the values 488 /// within a LazyCompoundVal to bind memberwise to the struct region, rather 489 /// than using a Default binding at the base of the entire region. This is a 490 /// heuristic attempting to avoid building long chains of LazyCompoundVals. 491 /// 492 /// \returns The updated store bindings, or \c std::nullopt if binding 493 /// non-lazily would be too expensive. 494 std::optional<RegionBindingsRef> 495 tryBindSmallStruct(RegionBindingsConstRef B, const TypedValueRegion *R, 496 const RecordDecl *RD, nonloc::LazyCompoundVal LCV); 497 498 /// BindStruct - Bind a compound value to a structure. 499 RegionBindingsRef bindStruct(RegionBindingsConstRef B, 500 const TypedValueRegion* R, SVal V); 501 502 /// BindVector - Bind a compound value to a vector. 503 RegionBindingsRef bindVector(RegionBindingsConstRef B, 504 const TypedValueRegion* R, SVal V); 505 506 std::optional<RegionBindingsRef> 507 tryBindSmallArray(RegionBindingsConstRef B, const TypedValueRegion *R, 508 const ArrayType *AT, nonloc::LazyCompoundVal LCV); 509 510 RegionBindingsRef bindArray(RegionBindingsConstRef B, 511 const TypedValueRegion* R, 512 SVal V); 513 514 /// Clears out all bindings in the given region and assigns a new value 515 /// as a Default binding. 516 RegionBindingsRef bindAggregate(RegionBindingsConstRef B, 517 const TypedRegion *R, 518 SVal DefaultVal); 519 520 /// Create a new store with the specified binding removed. 521 /// \param ST the original store, that is the basis for the new store. 522 /// \param L the location whose binding should be removed. 523 StoreRef killBinding(Store ST, Loc L) override; 524 525 void incrementReferenceCount(Store store) override { 526 getRegionBindings(store).manualRetain(); 527 } 528 529 /// If the StoreManager supports it, decrement the reference count of 530 /// the specified Store object. If the reference count hits 0, the memory 531 /// associated with the object is recycled. 532 void decrementReferenceCount(Store store) override { 533 getRegionBindings(store).manualRelease(); 534 } 535 536 bool includedInBindings(Store store, const MemRegion *region) const override; 537 538 /// Return the value bound to specified location in a given state. 539 /// 540 /// The high level logic for this method is this: 541 /// getBinding (L) 542 /// if L has binding 543 /// return L's binding 544 /// else if L is in killset 545 /// return unknown 546 /// else 547 /// if L is on stack or heap 548 /// return undefined 549 /// else 550 /// return symbolic 551 SVal getBinding(Store S, Loc L, QualType T) override { 552 return getBinding(getRegionBindings(S), L, T); 553 } 554 555 std::optional<SVal> getDefaultBinding(Store S, const MemRegion *R) override { 556 RegionBindingsRef B = getRegionBindings(S); 557 // Default bindings are always applied over a base region so look up the 558 // base region's default binding, otherwise the lookup will fail when R 559 // is at an offset from R->getBaseRegion(). 560 return B.getDefaultBinding(R->getBaseRegion()); 561 } 562 563 SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType()); 564 565 SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R); 566 567 SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R); 568 569 SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R); 570 571 SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R); 572 573 SVal getBindingForLazySymbol(const TypedValueRegion *R); 574 575 SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 576 const TypedValueRegion *R, 577 QualType Ty); 578 579 SVal getLazyBinding(const SubRegion *LazyBindingRegion, 580 RegionBindingsRef LazyBinding); 581 582 /// Get bindings for the values in a struct and return a CompoundVal, used 583 /// when doing struct copy: 584 /// struct s x, y; 585 /// x = y; 586 /// y's value is retrieved by this method. 587 SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R); 588 SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R); 589 NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R); 590 591 /// Used to lazily generate derived symbols for bindings that are defined 592 /// implicitly by default bindings in a super region. 593 /// 594 /// Note that callers may need to specially handle LazyCompoundVals, which 595 /// are returned as is in case the caller needs to treat them differently. 596 std::optional<SVal> 597 getBindingForDerivedDefaultValue(RegionBindingsConstRef B, 598 const MemRegion *superR, 599 const TypedValueRegion *R, QualType Ty); 600 601 /// Get the state and region whose binding this region \p R corresponds to. 602 /// 603 /// If there is no lazy binding for \p R, the returned value will have a null 604 /// \c second. Note that a null pointer can represents a valid Store. 605 std::pair<Store, const SubRegion *> 606 findLazyBinding(RegionBindingsConstRef B, const SubRegion *R, 607 const SubRegion *originalRegion); 608 609 /// Returns the cached set of interesting SVals contained within a lazy 610 /// binding. 611 /// 612 /// The precise value of "interesting" is determined for the purposes of 613 /// RegionStore's internal analysis. It must always contain all regions and 614 /// symbols, but may omit constants and other kinds of SVal. 615 /// 616 /// In contrast to compound values, LazyCompoundVals are also added 617 /// to the 'interesting values' list in addition to the child interesting 618 /// values. 619 const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV); 620 621 //===------------------------------------------------------------------===// 622 // State pruning. 623 //===------------------------------------------------------------------===// 624 625 /// removeDeadBindings - Scans the RegionStore of 'state' for dead values. 626 /// It returns a new Store with these values removed. 627 StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx, 628 SymbolReaper& SymReaper) override; 629 630 //===------------------------------------------------------------------===// 631 // Utility methods. 632 //===------------------------------------------------------------------===// 633 634 RegionBindingsRef getRegionBindings(Store store) const { 635 llvm::PointerIntPair<Store, 1, bool> Ptr; 636 Ptr.setFromOpaqueValue(const_cast<void *>(store)); 637 return RegionBindingsRef( 638 CBFactory, 639 static_cast<const RegionBindings::TreeTy *>(Ptr.getPointer()), 640 RBFactory.getTreeFactory(), 641 Ptr.getInt()); 642 } 643 644 void printJson(raw_ostream &Out, Store S, const char *NL = "\n", 645 unsigned int Space = 0, bool IsDot = false) const override; 646 647 void iterBindings(Store store, BindingsHandler& f) override { 648 RegionBindingsRef B = getRegionBindings(store); 649 for (const auto &[Region, Cluster] : B) { 650 for (const auto &[Key, Value] : Cluster) { 651 if (!Key.isDirect()) 652 continue; 653 if (const SubRegion *R = dyn_cast<SubRegion>(Key.getRegion())) { 654 // FIXME: Possibly incorporate the offset? 655 if (!f.HandleBinding(*this, store, R, Value)) 656 return; 657 } 658 } 659 } 660 } 661}; 662 663} // end anonymous namespace 664 665//===----------------------------------------------------------------------===// 666// RegionStore creation. 667//===----------------------------------------------------------------------===// 668 669std::unique_ptr<StoreManager> 670ento::CreateRegionStoreManager(ProgramStateManager &StMgr) { 671 return std::make_unique<RegionStoreManager>(StMgr); 672} 673 674//===----------------------------------------------------------------------===// 675// Region Cluster analysis. 676//===----------------------------------------------------------------------===// 677 678namespace { 679/// Used to determine which global regions are automatically included in the 680/// initial worklist of a ClusterAnalysis. 681enum GlobalsFilterKind { 682 /// Don't include any global regions. 683 GFK_None, 684 /// Only include system globals. 685 GFK_SystemOnly, 686 /// Include all global regions. 687 GFK_All 688}; 689 690template <typename DERIVED> 691class ClusterAnalysis { 692protected: 693 typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap; 694 typedef const MemRegion * WorkListElement; 695 typedef SmallVector<WorkListElement, 10> WorkList; 696 697 llvm::SmallPtrSet<const ClusterBindings *, 16> Visited; 698 699 WorkList WL; 700 701 RegionStoreManager &RM; 702 ASTContext &Ctx; 703 SValBuilder &svalBuilder; 704 705 RegionBindingsRef B; 706 707 708protected: 709 const ClusterBindings *getCluster(const MemRegion *R) { 710 return B.lookup(R); 711 } 712 713 /// Returns true if all clusters in the given memspace should be initially 714 /// included in the cluster analysis. Subclasses may provide their 715 /// own implementation. 716 bool includeEntireMemorySpace(const MemRegion *Base) { 717 return false; 718 } 719 720public: 721 ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr, 722 RegionBindingsRef b) 723 : RM(rm), Ctx(StateMgr.getContext()), 724 svalBuilder(StateMgr.getSValBuilder()), B(std::move(b)) {} 725 726 RegionBindingsRef getRegionBindings() const { return B; } 727 728 bool isVisited(const MemRegion *R) { 729 return Visited.count(getCluster(R)); 730 } 731 732 void GenerateClusters() { 733 // Scan the entire set of bindings and record the region clusters. 734 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); 735 RI != RE; ++RI){ 736 const MemRegion *Base = RI.getKey(); 737 738 const ClusterBindings &Cluster = RI.getData(); 739 assert(!Cluster.isEmpty() && "Empty clusters should be removed"); 740 static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster); 741 742 // If the base's memspace should be entirely invalidated, add the cluster 743 // to the workspace up front. 744 if (static_cast<DERIVED*>(this)->includeEntireMemorySpace(Base)) 745 AddToWorkList(WorkListElement(Base), &Cluster); 746 } 747 } 748 749 bool AddToWorkList(WorkListElement E, const ClusterBindings *C) { 750 if (C && !Visited.insert(C).second) 751 return false; 752 WL.push_back(E); 753 return true; 754 } 755 756 bool AddToWorkList(const MemRegion *R) { 757 return static_cast<DERIVED*>(this)->AddToWorkList(R); 758 } 759 760 void RunWorkList() { 761 while (!WL.empty()) { 762 WorkListElement E = WL.pop_back_val(); 763 const MemRegion *BaseR = E; 764 765 static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(BaseR)); 766 } 767 } 768 769 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {} 770 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {} 771 772 void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C, 773 bool Flag) { 774 static_cast<DERIVED*>(this)->VisitCluster(BaseR, C); 775 } 776}; 777} 778 779//===----------------------------------------------------------------------===// 780// Binding invalidation. 781//===----------------------------------------------------------------------===// 782 783bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R, 784 ScanReachableSymbols &Callbacks) { 785 assert(R == R->getBaseRegion() && "Should only be called for base regions"); 786 RegionBindingsRef B = getRegionBindings(S); 787 const ClusterBindings *Cluster = B.lookup(R); 788 789 if (!Cluster) 790 return true; 791 792 for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end(); 793 RI != RE; ++RI) { 794 if (!Callbacks.scan(RI.getData())) 795 return false; 796 } 797 798 return true; 799} 800 801static inline bool isUnionField(const FieldRegion *FR) { 802 return FR->getDecl()->getParent()->isUnion(); 803} 804 805typedef SmallVector<const FieldDecl *, 8> FieldVector; 806 807static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) { 808 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 809 810 const MemRegion *Base = K.getConcreteOffsetRegion(); 811 const MemRegion *R = K.getRegion(); 812 813 while (R != Base) { 814 if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) 815 if (!isUnionField(FR)) 816 Fields.push_back(FR->getDecl()); 817 818 R = cast<SubRegion>(R)->getSuperRegion(); 819 } 820} 821 822static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) { 823 assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys"); 824 825 if (Fields.empty()) 826 return true; 827 828 FieldVector FieldsInBindingKey; 829 getSymbolicOffsetFields(K, FieldsInBindingKey); 830 831 ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size(); 832 if (Delta >= 0) 833 return std::equal(FieldsInBindingKey.begin() + Delta, 834 FieldsInBindingKey.end(), 835 Fields.begin()); 836 else 837 return std::equal(FieldsInBindingKey.begin(), FieldsInBindingKey.end(), 838 Fields.begin() - Delta); 839} 840 841/// Collects all bindings in \p Cluster that may refer to bindings within 842/// \p Top. 843/// 844/// Each binding is a pair whose \c first is the key (a BindingKey) and whose 845/// \c second is the value (an SVal). 846/// 847/// The \p IncludeAllDefaultBindings parameter specifies whether to include 848/// default bindings that may extend beyond \p Top itself, e.g. if \p Top is 849/// an aggregate within a larger aggregate with a default binding. 850static void 851collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 852 SValBuilder &SVB, const ClusterBindings &Cluster, 853 const SubRegion *Top, BindingKey TopKey, 854 bool IncludeAllDefaultBindings) { 855 FieldVector FieldsInSymbolicSubregions; 856 if (TopKey.hasSymbolicOffset()) { 857 getSymbolicOffsetFields(TopKey, FieldsInSymbolicSubregions); 858 Top = TopKey.getConcreteOffsetRegion(); 859 TopKey = BindingKey::Make(Top, BindingKey::Default); 860 } 861 862 // Find the length (in bits) of the region being invalidated. 863 uint64_t Length = UINT64_MAX; 864 SVal Extent = Top->getMemRegionManager().getStaticSize(Top, SVB); 865 if (std::optional<nonloc::ConcreteInt> ExtentCI = 866 Extent.getAs<nonloc::ConcreteInt>()) { 867 const llvm::APSInt &ExtentInt = ExtentCI->getValue(); 868 assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned()); 869 // Extents are in bytes but region offsets are in bits. Be careful! 870 Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth(); 871 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Top)) { 872 if (FR->getDecl()->isBitField()) 873 Length = FR->getDecl()->getBitWidthValue(SVB.getContext()); 874 } 875 876 for (const auto &StoreEntry : Cluster) { 877 BindingKey NextKey = StoreEntry.first; 878 if (NextKey.getRegion() == TopKey.getRegion()) { 879 // FIXME: This doesn't catch the case where we're really invalidating a 880 // region with a symbolic offset. Example: 881 // R: points[i].y 882 // Next: points[0].x 883 884 if (NextKey.getOffset() > TopKey.getOffset() && 885 NextKey.getOffset() - TopKey.getOffset() < Length) { 886 // Case 1: The next binding is inside the region we're invalidating. 887 // Include it. 888 Bindings.push_back(StoreEntry); 889 890 } else if (NextKey.getOffset() == TopKey.getOffset()) { 891 // Case 2: The next binding is at the same offset as the region we're 892 // invalidating. In this case, we need to leave default bindings alone, 893 // since they may be providing a default value for a regions beyond what 894 // we're invalidating. 895 // FIXME: This is probably incorrect; consider invalidating an outer 896 // struct whose first field is bound to a LazyCompoundVal. 897 if (IncludeAllDefaultBindings || NextKey.isDirect()) 898 Bindings.push_back(StoreEntry); 899 } 900 901 } else if (NextKey.hasSymbolicOffset()) { 902 const MemRegion *Base = NextKey.getConcreteOffsetRegion(); 903 if (Top->isSubRegionOf(Base) && Top != Base) { 904 // Case 3: The next key is symbolic and we just changed something within 905 // its concrete region. We don't know if the binding is still valid, so 906 // we'll be conservative and include it. 907 if (IncludeAllDefaultBindings || NextKey.isDirect()) 908 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 909 Bindings.push_back(StoreEntry); 910 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Base)) { 911 // Case 4: The next key is symbolic, but we changed a known 912 // super-region. In this case the binding is certainly included. 913 if (BaseSR->isSubRegionOf(Top)) 914 if (isCompatibleWithFields(NextKey, FieldsInSymbolicSubregions)) 915 Bindings.push_back(StoreEntry); 916 } 917 } 918 } 919} 920 921static void 922collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings, 923 SValBuilder &SVB, const ClusterBindings &Cluster, 924 const SubRegion *Top, bool IncludeAllDefaultBindings) { 925 collectSubRegionBindings(Bindings, SVB, Cluster, Top, 926 BindingKey::Make(Top, BindingKey::Default), 927 IncludeAllDefaultBindings); 928} 929 930RegionBindingsRef 931RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B, 932 const SubRegion *Top) { 933 BindingKey TopKey = BindingKey::Make(Top, BindingKey::Default); 934 const MemRegion *ClusterHead = TopKey.getBaseRegion(); 935 936 if (Top == ClusterHead) { 937 // We can remove an entire cluster's bindings all in one go. 938 return B.remove(Top); 939 } 940 941 const ClusterBindings *Cluster = B.lookup(ClusterHead); 942 if (!Cluster) { 943 // If we're invalidating a region with a symbolic offset, we need to make 944 // sure we don't treat the base region as uninitialized anymore. 945 if (TopKey.hasSymbolicOffset()) { 946 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 947 return B.addBinding(Concrete, BindingKey::Default, UnknownVal()); 948 } 949 return B; 950 } 951 952 SmallVector<BindingPair, 32> Bindings; 953 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, Top, TopKey, 954 /*IncludeAllDefaultBindings=*/false); 955 956 ClusterBindingsRef Result(*Cluster, CBFactory); 957 for (BindingKey Key : llvm::make_first_range(Bindings)) 958 Result = Result.remove(Key); 959 960 // If we're invalidating a region with a symbolic offset, we need to make sure 961 // we don't treat the base region as uninitialized anymore. 962 // FIXME: This isn't very precise; see the example in 963 // collectSubRegionBindings. 964 if (TopKey.hasSymbolicOffset()) { 965 const SubRegion *Concrete = TopKey.getConcreteOffsetRegion(); 966 Result = Result.add(BindingKey::Make(Concrete, BindingKey::Default), 967 UnknownVal()); 968 } 969 970 if (Result.isEmpty()) 971 return B.remove(ClusterHead); 972 return B.add(ClusterHead, Result.asImmutableMap()); 973} 974 975namespace { 976class InvalidateRegionsWorker : public ClusterAnalysis<InvalidateRegionsWorker> 977{ 978 const Expr *Ex; 979 unsigned Count; 980 const LocationContext *LCtx; 981 InvalidatedSymbols &IS; 982 RegionAndSymbolInvalidationTraits &ITraits; 983 StoreManager::InvalidatedRegions *Regions; 984 GlobalsFilterKind GlobalsFilter; 985public: 986 InvalidateRegionsWorker(RegionStoreManager &rm, 987 ProgramStateManager &stateMgr, 988 RegionBindingsRef b, 989 const Expr *ex, unsigned count, 990 const LocationContext *lctx, 991 InvalidatedSymbols &is, 992 RegionAndSymbolInvalidationTraits &ITraitsIn, 993 StoreManager::InvalidatedRegions *r, 994 GlobalsFilterKind GFK) 995 : ClusterAnalysis<InvalidateRegionsWorker>(rm, stateMgr, b), 996 Ex(ex), Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r), 997 GlobalsFilter(GFK) {} 998 999 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C); 1000 void VisitBinding(SVal V); 1001 1002 using ClusterAnalysis::AddToWorkList; 1003 1004 bool AddToWorkList(const MemRegion *R); 1005 1006 /// Returns true if all clusters in the memory space for \p Base should be 1007 /// be invalidated. 1008 bool includeEntireMemorySpace(const MemRegion *Base); 1009 1010 /// Returns true if the memory space of the given region is one of the global 1011 /// regions specially included at the start of invalidation. 1012 bool isInitiallyIncludedGlobalRegion(const MemRegion *R); 1013}; 1014} 1015 1016bool InvalidateRegionsWorker::AddToWorkList(const MemRegion *R) { 1017 bool doNotInvalidateSuperRegion = ITraits.hasTrait( 1018 R, RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion); 1019 const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion(); 1020 return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR)); 1021} 1022 1023void InvalidateRegionsWorker::VisitBinding(SVal V) { 1024 // A symbol? Mark it touched by the invalidation. 1025 if (SymbolRef Sym = V.getAsSymbol()) 1026 IS.insert(Sym); 1027 1028 if (const MemRegion *R = V.getAsRegion()) { 1029 AddToWorkList(R); 1030 return; 1031 } 1032 1033 // Is it a LazyCompoundVal? All references get invalidated as well. 1034 if (std::optional<nonloc::LazyCompoundVal> LCS = 1035 V.getAs<nonloc::LazyCompoundVal>()) { 1036 1037 // `getInterestingValues()` returns SVals contained within LazyCompoundVals, 1038 // so there is no need to visit them. 1039 for (SVal V : RM.getInterestingValues(*LCS)) 1040 if (!isa<nonloc::LazyCompoundVal>(V)) 1041 VisitBinding(V); 1042 1043 return; 1044 } 1045} 1046 1047void InvalidateRegionsWorker::VisitCluster(const MemRegion *baseR, 1048 const ClusterBindings *C) { 1049 1050 bool PreserveRegionsContents = 1051 ITraits.hasTrait(baseR, 1052 RegionAndSymbolInvalidationTraits::TK_PreserveContents); 1053 1054 if (C) { 1055 for (SVal Val : llvm::make_second_range(*C)) 1056 VisitBinding(Val); 1057 1058 // Invalidate regions contents. 1059 if (!PreserveRegionsContents) 1060 B = B.remove(baseR); 1061 } 1062 1063 if (const auto *TO = dyn_cast<TypedValueRegion>(baseR)) { 1064 if (const auto *RD = TO->getValueType()->getAsCXXRecordDecl()) { 1065 1066 // Lambdas can affect all static local variables without explicitly 1067 // capturing those. 1068 // We invalidate all static locals referenced inside the lambda body. 1069 if (RD->isLambda() && RD->getLambdaCallOperator()->getBody()) { 1070 using namespace ast_matchers; 1071 1072 const char *DeclBind = "DeclBind"; 1073 StatementMatcher RefToStatic = stmt(hasDescendant(declRefExpr( 1074 to(varDecl(hasStaticStorageDuration()).bind(DeclBind))))); 1075 auto Matches = 1076 match(RefToStatic, *RD->getLambdaCallOperator()->getBody(), 1077 RD->getASTContext()); 1078 1079 for (BoundNodes &Match : Matches) { 1080 auto *VD = Match.getNodeAs<VarDecl>(DeclBind); 1081 const VarRegion *ToInvalidate = 1082 RM.getRegionManager().getVarRegion(VD, LCtx); 1083 AddToWorkList(ToInvalidate); 1084 } 1085 } 1086 } 1087 } 1088 1089 // BlockDataRegion? If so, invalidate captured variables that are passed 1090 // by reference. 1091 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) { 1092 for (auto Var : BR->referenced_vars()) { 1093 const VarRegion *VR = Var.getCapturedRegion(); 1094 const VarDecl *VD = VR->getDecl(); 1095 if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage()) { 1096 AddToWorkList(VR); 1097 } 1098 else if (Loc::isLocType(VR->getValueType())) { 1099 // Map the current bindings to a Store to retrieve the value 1100 // of the binding. If that binding itself is a region, we should 1101 // invalidate that region. This is because a block may capture 1102 // a pointer value, but the thing pointed by that pointer may 1103 // get invalidated. 1104 SVal V = RM.getBinding(B, loc::MemRegionVal(VR)); 1105 if (std::optional<Loc> L = V.getAs<Loc>()) { 1106 if (const MemRegion *LR = L->getAsRegion()) 1107 AddToWorkList(LR); 1108 } 1109 } 1110 } 1111 return; 1112 } 1113 1114 // Symbolic region? 1115 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) 1116 IS.insert(SR->getSymbol()); 1117 1118 // Nothing else should be done in the case when we preserve regions context. 1119 if (PreserveRegionsContents) 1120 return; 1121 1122 // Otherwise, we have a normal data region. Record that we touched the region. 1123 if (Regions) 1124 Regions->push_back(baseR); 1125 1126 if (isa<AllocaRegion, SymbolicRegion>(baseR)) { 1127 // Invalidate the region by setting its default value to 1128 // conjured symbol. The type of the symbol is irrelevant. 1129 DefinedOrUnknownSVal V = 1130 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, Ctx.IntTy, Count); 1131 B = B.addBinding(baseR, BindingKey::Default, V); 1132 return; 1133 } 1134 1135 if (!baseR->isBoundable()) 1136 return; 1137 1138 const TypedValueRegion *TR = cast<TypedValueRegion>(baseR); 1139 QualType T = TR->getValueType(); 1140 1141 if (isInitiallyIncludedGlobalRegion(baseR)) { 1142 // If the region is a global and we are invalidating all globals, 1143 // erasing the entry is good enough. This causes all globals to be lazily 1144 // symbolicated from the same base symbol. 1145 return; 1146 } 1147 1148 if (T->isRecordType()) { 1149 // Invalidate the region by setting its default value to 1150 // conjured symbol. The type of the symbol is irrelevant. 1151 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1152 Ctx.IntTy, Count); 1153 B = B.addBinding(baseR, BindingKey::Default, V); 1154 return; 1155 } 1156 1157 if (const ArrayType *AT = Ctx.getAsArrayType(T)) { 1158 bool doNotInvalidateSuperRegion = ITraits.hasTrait( 1159 baseR, 1160 RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion); 1161 1162 if (doNotInvalidateSuperRegion) { 1163 // We are not doing blank invalidation of the whole array region so we 1164 // have to manually invalidate each elements. 1165 std::optional<uint64_t> NumElements; 1166 1167 // Compute lower and upper offsets for region within array. 1168 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(AT)) 1169 NumElements = CAT->getSize().getZExtValue(); 1170 if (!NumElements) // We are not dealing with a constant size array 1171 goto conjure_default; 1172 QualType ElementTy = AT->getElementType(); 1173 uint64_t ElemSize = Ctx.getTypeSize(ElementTy); 1174 const RegionOffset &RO = baseR->getAsOffset(); 1175 const MemRegion *SuperR = baseR->getBaseRegion(); 1176 if (RO.hasSymbolicOffset()) { 1177 // If base region has a symbolic offset, 1178 // we revert to invalidating the super region. 1179 if (SuperR) 1180 AddToWorkList(SuperR); 1181 goto conjure_default; 1182 } 1183 1184 uint64_t LowerOffset = RO.getOffset(); 1185 uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize; 1186 bool UpperOverflow = UpperOffset < LowerOffset; 1187 1188 // Invalidate regions which are within array boundaries, 1189 // or have a symbolic offset. 1190 if (!SuperR) 1191 goto conjure_default; 1192 1193 const ClusterBindings *C = B.lookup(SuperR); 1194 if (!C) 1195 goto conjure_default; 1196 1197 for (const auto &[BK, V] : *C) { 1198 std::optional<uint64_t> ROffset = 1199 BK.hasSymbolicOffset() ? std::optional<uint64_t>() : BK.getOffset(); 1200 1201 // Check offset is not symbolic and within array's boundaries. 1202 // Handles arrays of 0 elements and of 0-sized elements as well. 1203 if (!ROffset || 1204 ((*ROffset >= LowerOffset && *ROffset < UpperOffset) || 1205 (UpperOverflow && 1206 (*ROffset >= LowerOffset || *ROffset < UpperOffset)) || 1207 (LowerOffset == UpperOffset && *ROffset == LowerOffset))) { 1208 B = B.removeBinding(BK); 1209 // Bound symbolic regions need to be invalidated for dead symbol 1210 // detection. 1211 const MemRegion *R = V.getAsRegion(); 1212 if (isa_and_nonnull<SymbolicRegion>(R)) 1213 VisitBinding(V); 1214 } 1215 } 1216 } 1217 conjure_default: 1218 // Set the default value of the array to conjured symbol. 1219 DefinedOrUnknownSVal V = 1220 svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1221 AT->getElementType(), Count); 1222 B = B.addBinding(baseR, BindingKey::Default, V); 1223 return; 1224 } 1225 1226 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(baseR, Ex, LCtx, 1227 T,Count); 1228 assert(SymbolManager::canSymbolicate(T) || V.isUnknown()); 1229 B = B.addBinding(baseR, BindingKey::Direct, V); 1230} 1231 1232bool InvalidateRegionsWorker::isInitiallyIncludedGlobalRegion( 1233 const MemRegion *R) { 1234 switch (GlobalsFilter) { 1235 case GFK_None: 1236 return false; 1237 case GFK_SystemOnly: 1238 return isa<GlobalSystemSpaceRegion>(R->getMemorySpace()); 1239 case GFK_All: 1240 return isa<NonStaticGlobalSpaceRegion>(R->getMemorySpace()); 1241 } 1242 1243 llvm_unreachable("unknown globals filter"); 1244} 1245 1246bool InvalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) { 1247 if (isInitiallyIncludedGlobalRegion(Base)) 1248 return true; 1249 1250 const MemSpaceRegion *MemSpace = Base->getMemorySpace(); 1251 return ITraits.hasTrait(MemSpace, 1252 RegionAndSymbolInvalidationTraits::TK_EntireMemSpace); 1253} 1254 1255RegionBindingsRef 1256RegionStoreManager::invalidateGlobalRegion(MemRegion::Kind K, 1257 const Expr *Ex, 1258 unsigned Count, 1259 const LocationContext *LCtx, 1260 RegionBindingsRef B, 1261 InvalidatedRegions *Invalidated) { 1262 // Bind the globals memory space to a new symbol that we will use to derive 1263 // the bindings for all globals. 1264 const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K); 1265 SVal V = svalBuilder.conjureSymbolVal(/* symbolTag = */ (const void*) GS, Ex, LCtx, 1266 /* type does not matter */ Ctx.IntTy, 1267 Count); 1268 1269 B = B.removeBinding(GS) 1270 .addBinding(BindingKey::Make(GS, BindingKey::Default), V); 1271 1272 // Even if there are no bindings in the global scope, we still need to 1273 // record that we touched it. 1274 if (Invalidated) 1275 Invalidated->push_back(GS); 1276 1277 return B; 1278} 1279 1280void RegionStoreManager::populateWorkList(InvalidateRegionsWorker &W, 1281 ArrayRef<SVal> Values, 1282 InvalidatedRegions *TopLevelRegions) { 1283 for (SVal V : Values) { 1284 if (auto LCS = V.getAs<nonloc::LazyCompoundVal>()) { 1285 for (SVal S : getInterestingValues(*LCS)) 1286 if (const MemRegion *R = S.getAsRegion()) 1287 W.AddToWorkList(R); 1288 1289 continue; 1290 } 1291 1292 if (const MemRegion *R = V.getAsRegion()) { 1293 if (TopLevelRegions) 1294 TopLevelRegions->push_back(R); 1295 W.AddToWorkList(R); 1296 continue; 1297 } 1298 } 1299} 1300 1301StoreRef 1302RegionStoreManager::invalidateRegions(Store store, 1303 ArrayRef<SVal> Values, 1304 const Expr *Ex, unsigned Count, 1305 const LocationContext *LCtx, 1306 const CallEvent *Call, 1307 InvalidatedSymbols &IS, 1308 RegionAndSymbolInvalidationTraits &ITraits, 1309 InvalidatedRegions *TopLevelRegions, 1310 InvalidatedRegions *Invalidated) { 1311 GlobalsFilterKind GlobalsFilter; 1312 if (Call) { 1313 if (Call->isInSystemHeader()) 1314 GlobalsFilter = GFK_SystemOnly; 1315 else 1316 GlobalsFilter = GFK_All; 1317 } else { 1318 GlobalsFilter = GFK_None; 1319 } 1320 1321 RegionBindingsRef B = getRegionBindings(store); 1322 InvalidateRegionsWorker W(*this, StateMgr, B, Ex, Count, LCtx, IS, ITraits, 1323 Invalidated, GlobalsFilter); 1324 1325 // Scan the bindings and generate the clusters. 1326 W.GenerateClusters(); 1327 1328 // Add the regions to the worklist. 1329 populateWorkList(W, Values, TopLevelRegions); 1330 1331 W.RunWorkList(); 1332 1333 // Return the new bindings. 1334 B = W.getRegionBindings(); 1335 1336 // For calls, determine which global regions should be invalidated and 1337 // invalidate them. (Note that function-static and immutable globals are never 1338 // invalidated by this.) 1339 // TODO: This could possibly be more precise with modules. 1340 switch (GlobalsFilter) { 1341 case GFK_All: 1342 B = invalidateGlobalRegion(MemRegion::GlobalInternalSpaceRegionKind, 1343 Ex, Count, LCtx, B, Invalidated); 1344 [[fallthrough]]; 1345 case GFK_SystemOnly: 1346 B = invalidateGlobalRegion(MemRegion::GlobalSystemSpaceRegionKind, 1347 Ex, Count, LCtx, B, Invalidated); 1348 [[fallthrough]]; 1349 case GFK_None: 1350 break; 1351 } 1352 1353 return StoreRef(B.asStore(), *this); 1354} 1355 1356//===----------------------------------------------------------------------===// 1357// Location and region casting. 1358//===----------------------------------------------------------------------===// 1359 1360/// ArrayToPointer - Emulates the "decay" of an array to a pointer 1361/// type. 'Array' represents the lvalue of the array being decayed 1362/// to a pointer, and the returned SVal represents the decayed 1363/// version of that lvalue (i.e., a pointer to the first element of 1364/// the array). This is called by ExprEngine when evaluating casts 1365/// from arrays to pointers. 1366SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) { 1367 if (isa<loc::ConcreteInt>(Array)) 1368 return Array; 1369 1370 if (!isa<loc::MemRegionVal>(Array)) 1371 return UnknownVal(); 1372 1373 const SubRegion *R = 1374 cast<SubRegion>(Array.castAs<loc::MemRegionVal>().getRegion()); 1375 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex(); 1376 return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, R, Ctx)); 1377} 1378 1379//===----------------------------------------------------------------------===// 1380// Loading values from regions. 1381//===----------------------------------------------------------------------===// 1382 1383SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) { 1384 assert(!isa<UnknownVal>(L) && "location unknown"); 1385 assert(!isa<UndefinedVal>(L) && "location undefined"); 1386 1387 // For access to concrete addresses, return UnknownVal. Checks 1388 // for null dereferences (and similar errors) are done by checkers, not 1389 // the Store. 1390 // FIXME: We can consider lazily symbolicating such memory, but we really 1391 // should defer this when we can reason easily about symbolicating arrays 1392 // of bytes. 1393 if (L.getAs<loc::ConcreteInt>()) { 1394 return UnknownVal(); 1395 } 1396 if (!L.getAs<loc::MemRegionVal>()) { 1397 return UnknownVal(); 1398 } 1399 1400 const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion(); 1401 1402 if (isa<BlockDataRegion>(MR)) { 1403 return UnknownVal(); 1404 } 1405 1406 // Auto-detect the binding type. 1407 if (T.isNull()) { 1408 if (const auto *TVR = dyn_cast<TypedValueRegion>(MR)) 1409 T = TVR->getValueType(); 1410 else if (const auto *TR = dyn_cast<TypedRegion>(MR)) 1411 T = TR->getLocationType()->getPointeeType(); 1412 else if (const auto *SR = dyn_cast<SymbolicRegion>(MR)) 1413 T = SR->getPointeeStaticType(); 1414 } 1415 assert(!T.isNull() && "Unable to auto-detect binding type!"); 1416 assert(!T->isVoidType() && "Attempting to dereference a void pointer!"); 1417 1418 if (!isa<TypedValueRegion>(MR)) 1419 MR = GetElementZeroRegion(cast<SubRegion>(MR), T); 1420 1421 // FIXME: Perhaps this method should just take a 'const MemRegion*' argument 1422 // instead of 'Loc', and have the other Loc cases handled at a higher level. 1423 const TypedValueRegion *R = cast<TypedValueRegion>(MR); 1424 QualType RTy = R->getValueType(); 1425 1426 // FIXME: we do not yet model the parts of a complex type, so treat the 1427 // whole thing as "unknown". 1428 if (RTy->isAnyComplexType()) 1429 return UnknownVal(); 1430 1431 // FIXME: We should eventually handle funny addressing. e.g.: 1432 // 1433 // int x = ...; 1434 // int *p = &x; 1435 // char *q = (char*) p; 1436 // char c = *q; // returns the first byte of 'x'. 1437 // 1438 // Such funny addressing will occur due to layering of regions. 1439 if (RTy->isStructureOrClassType()) 1440 return getBindingForStruct(B, R); 1441 1442 // FIXME: Handle unions. 1443 if (RTy->isUnionType()) 1444 return createLazyBinding(B, R); 1445 1446 if (RTy->isArrayType()) { 1447 if (RTy->isConstantArrayType()) 1448 return getBindingForArray(B, R); 1449 else 1450 return UnknownVal(); 1451 } 1452 1453 // FIXME: handle Vector types. 1454 if (RTy->isVectorType()) 1455 return UnknownVal(); 1456 1457 if (const FieldRegion* FR = dyn_cast<FieldRegion>(R)) 1458 return svalBuilder.evalCast(getBindingForField(B, FR), T, QualType{}); 1459 1460 if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) { 1461 // FIXME: Here we actually perform an implicit conversion from the loaded 1462 // value to the element type. Eventually we want to compose these values 1463 // more intelligently. For example, an 'element' can encompass multiple 1464 // bound regions (e.g., several bound bytes), or could be a subset of 1465 // a larger value. 1466 return svalBuilder.evalCast(getBindingForElement(B, ER), T, QualType{}); 1467 } 1468 1469 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) { 1470 // FIXME: Here we actually perform an implicit conversion from the loaded 1471 // value to the ivar type. What we should model is stores to ivars 1472 // that blow past the extent of the ivar. If the address of the ivar is 1473 // reinterpretted, it is possible we stored a different value that could 1474 // fit within the ivar. Either we need to cast these when storing them 1475 // or reinterpret them lazily (as we do here). 1476 return svalBuilder.evalCast(getBindingForObjCIvar(B, IVR), T, QualType{}); 1477 } 1478 1479 if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { 1480 // FIXME: Here we actually perform an implicit conversion from the loaded 1481 // value to the variable type. What we should model is stores to variables 1482 // that blow past the extent of the variable. If the address of the 1483 // variable is reinterpretted, it is possible we stored a different value 1484 // that could fit within the variable. Either we need to cast these when 1485 // storing them or reinterpret them lazily (as we do here). 1486 return svalBuilder.evalCast(getBindingForVar(B, VR), T, QualType{}); 1487 } 1488 1489 const SVal *V = B.lookup(R, BindingKey::Direct); 1490 1491 // Check if the region has a binding. 1492 if (V) 1493 return *V; 1494 1495 // The location does not have a bound value. This means that it has 1496 // the value it had upon its creation and/or entry to the analyzed 1497 // function/method. These are either symbolic values or 'undefined'. 1498 if (R->hasStackNonParametersStorage()) { 1499 // All stack variables are considered to have undefined values 1500 // upon creation. All heap allocated blocks are considered to 1501 // have undefined values as well unless they are explicitly bound 1502 // to specific values. 1503 return UndefinedVal(); 1504 } 1505 1506 // All other values are symbolic. 1507 return svalBuilder.getRegionValueSymbolVal(R); 1508} 1509 1510static QualType getUnderlyingType(const SubRegion *R) { 1511 QualType RegionTy; 1512 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) 1513 RegionTy = TVR->getValueType(); 1514 1515 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 1516 RegionTy = SR->getSymbol()->getType(); 1517 1518 return RegionTy; 1519} 1520 1521/// Checks to see if store \p B has a lazy binding for region \p R. 1522/// 1523/// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected 1524/// if there are additional bindings within \p R. 1525/// 1526/// Note that unlike RegionStoreManager::findLazyBinding, this will not search 1527/// for lazy bindings for super-regions of \p R. 1528static std::optional<nonloc::LazyCompoundVal> 1529getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B, 1530 const SubRegion *R, bool AllowSubregionBindings) { 1531 std::optional<SVal> V = B.getDefaultBinding(R); 1532 if (!V) 1533 return std::nullopt; 1534 1535 std::optional<nonloc::LazyCompoundVal> LCV = 1536 V->getAs<nonloc::LazyCompoundVal>(); 1537 if (!LCV) 1538 return std::nullopt; 1539 1540 // If the LCV is for a subregion, the types might not match, and we shouldn't 1541 // reuse the binding. 1542 QualType RegionTy = getUnderlyingType(R); 1543 if (!RegionTy.isNull() && 1544 !RegionTy->isVoidPointerType()) { 1545 QualType SourceRegionTy = LCV->getRegion()->getValueType(); 1546 if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy)) 1547 return std::nullopt; 1548 } 1549 1550 if (!AllowSubregionBindings) { 1551 // If there are any other bindings within this region, we shouldn't reuse 1552 // the top-level binding. 1553 SmallVector<BindingPair, 16> Bindings; 1554 collectSubRegionBindings(Bindings, SVB, *B.lookup(R->getBaseRegion()), R, 1555 /*IncludeAllDefaultBindings=*/true); 1556 if (Bindings.size() > 1) 1557 return std::nullopt; 1558 } 1559 1560 return *LCV; 1561} 1562 1563std::pair<Store, const SubRegion *> 1564RegionStoreManager::findLazyBinding(RegionBindingsConstRef B, 1565 const SubRegion *R, 1566 const SubRegion *originalRegion) { 1567 if (originalRegion != R) { 1568 if (std::optional<nonloc::LazyCompoundVal> V = 1569 getExistingLazyBinding(svalBuilder, B, R, true)) 1570 return std::make_pair(V->getStore(), V->getRegion()); 1571 } 1572 1573 typedef std::pair<Store, const SubRegion *> StoreRegionPair; 1574 StoreRegionPair Result = StoreRegionPair(); 1575 1576 if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) { 1577 Result = findLazyBinding(B, cast<SubRegion>(ER->getSuperRegion()), 1578 originalRegion); 1579 1580 if (Result.second) 1581 Result.second = MRMgr.getElementRegionWithSuper(ER, Result.second); 1582 1583 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) { 1584 Result = findLazyBinding(B, cast<SubRegion>(FR->getSuperRegion()), 1585 originalRegion); 1586 1587 if (Result.second) 1588 Result.second = MRMgr.getFieldRegionWithSuper(FR, Result.second); 1589 1590 } else if (const CXXBaseObjectRegion *BaseReg = 1591 dyn_cast<CXXBaseObjectRegion>(R)) { 1592 // C++ base object region is another kind of region that we should blast 1593 // through to look for lazy compound value. It is like a field region. 1594 Result = findLazyBinding(B, cast<SubRegion>(BaseReg->getSuperRegion()), 1595 originalRegion); 1596 1597 if (Result.second) 1598 Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(BaseReg, 1599 Result.second); 1600 } 1601 1602 return Result; 1603} 1604 1605/// This is a helper function for `getConstantValFromConstArrayInitializer`. 1606/// 1607/// Return an array of extents of the declared array type. 1608/// 1609/// E.g. for `int x[1][2][3];` returns { 1, 2, 3 }. 1610static SmallVector<uint64_t, 2> 1611getConstantArrayExtents(const ConstantArrayType *CAT) { 1612 assert(CAT && "ConstantArrayType should not be null"); 1613 CAT = cast<ConstantArrayType>(CAT->getCanonicalTypeInternal()); 1614 SmallVector<uint64_t, 2> Extents; 1615 do { 1616 Extents.push_back(CAT->getSize().getZExtValue()); 1617 } while ((CAT = dyn_cast<ConstantArrayType>(CAT->getElementType()))); 1618 return Extents; 1619} 1620 1621/// This is a helper function for `getConstantValFromConstArrayInitializer`. 1622/// 1623/// Return an array of offsets from nested ElementRegions and a root base 1624/// region. The array is never empty and a base region is never null. 1625/// 1626/// E.g. for `Element{Element{Element{VarRegion},1},2},3}` returns { 3, 2, 1 }. 1627/// This represents an access through indirection: `arr[1][2][3];` 1628/// 1629/// \param ER The given (possibly nested) ElementRegion. 1630/// 1631/// \note The result array is in the reverse order of indirection expression: 1632/// arr[1][2][3] -> { 3, 2, 1 }. This helps to provide complexity O(n), where n 1633/// is a number of indirections. It may not affect performance in real-life 1634/// code, though. 1635static std::pair<SmallVector<SVal, 2>, const MemRegion *> 1636getElementRegionOffsetsWithBase(const ElementRegion *ER) { 1637 assert(ER && "ConstantArrayType should not be null"); 1638 const MemRegion *Base; 1639 SmallVector<SVal, 2> SValOffsets; 1640 do { 1641 SValOffsets.push_back(ER->getIndex()); 1642 Base = ER->getSuperRegion(); 1643 ER = dyn_cast<ElementRegion>(Base); 1644 } while (ER); 1645 return {SValOffsets, Base}; 1646} 1647 1648/// This is a helper function for `getConstantValFromConstArrayInitializer`. 1649/// 1650/// Convert array of offsets from `SVal` to `uint64_t` in consideration of 1651/// respective array extents. 1652/// \param SrcOffsets [in] The array of offsets of type `SVal` in reversed 1653/// order (expectedly received from `getElementRegionOffsetsWithBase`). 1654/// \param ArrayExtents [in] The array of extents. 1655/// \param DstOffsets [out] The array of offsets of type `uint64_t`. 1656/// \returns: 1657/// - `std::nullopt` for successful convertion. 1658/// - `UndefinedVal` or `UnknownVal` otherwise. It's expected that this SVal 1659/// will be returned as a suitable value of the access operation. 1660/// which should be returned as a correct 1661/// 1662/// \example: 1663/// const int arr[10][20][30] = {}; // ArrayExtents { 10, 20, 30 } 1664/// int x1 = arr[4][5][6]; // SrcOffsets { NonLoc(6), NonLoc(5), NonLoc(4) } 1665/// // DstOffsets { 4, 5, 6 } 1666/// // returns std::nullopt 1667/// int x2 = arr[42][5][-6]; // returns UndefinedVal 1668/// int x3 = arr[4][5][x2]; // returns UnknownVal 1669static std::optional<SVal> 1670convertOffsetsFromSvalToUnsigneds(const SmallVector<SVal, 2> &SrcOffsets, 1671 const SmallVector<uint64_t, 2> ArrayExtents, 1672 SmallVector<uint64_t, 2> &DstOffsets) { 1673 // Check offsets for being out of bounds. 1674 // C++20 [expr.add] 7.6.6.4 (excerpt): 1675 // If P points to an array element i of an array object x with n 1676 // elements, where i < 0 or i > n, the behavior is undefined. 1677 // Dereferencing is not allowed on the "one past the last 1678 // element", when i == n. 1679 // Example: 1680 // const int arr[3][2] = {{1, 2}, {3, 4}}; 1681 // arr[0][0]; // 1 1682 // arr[0][1]; // 2 1683 // arr[0][2]; // UB 1684 // arr[1][0]; // 3 1685 // arr[1][1]; // 4 1686 // arr[1][-1]; // UB 1687 // arr[2][0]; // 0 1688 // arr[2][1]; // 0 1689 // arr[-2][0]; // UB 1690 DstOffsets.resize(SrcOffsets.size()); 1691 auto ExtentIt = ArrayExtents.begin(); 1692 auto OffsetIt = DstOffsets.begin(); 1693 // Reverse `SValOffsets` to make it consistent with `ArrayExtents`. 1694 for (SVal V : llvm::reverse(SrcOffsets)) { 1695 if (auto CI = V.getAs<nonloc::ConcreteInt>()) { 1696 // When offset is out of array's bounds, result is UB. 1697 const llvm::APSInt &Offset = CI->getValue(); 1698 if (Offset.isNegative() || Offset.uge(*(ExtentIt++))) 1699 return UndefinedVal(); 1700 // Store index in a reversive order. 1701 *(OffsetIt++) = Offset.getZExtValue(); 1702 continue; 1703 } 1704 // Symbolic index presented. Return Unknown value. 1705 // FIXME: We also need to take ElementRegions with symbolic indexes into 1706 // account. 1707 return UnknownVal(); 1708 } 1709 return std::nullopt; 1710} 1711 1712std::optional<SVal> RegionStoreManager::getConstantValFromConstArrayInitializer( 1713 RegionBindingsConstRef B, const ElementRegion *R) { 1714 assert(R && "ElementRegion should not be null"); 1715 1716 // Treat an n-dimensional array. 1717 SmallVector<SVal, 2> SValOffsets; 1718 const MemRegion *Base; 1719 std::tie(SValOffsets, Base) = getElementRegionOffsetsWithBase(R); 1720 const VarRegion *VR = dyn_cast<VarRegion>(Base); 1721 if (!VR) 1722 return std::nullopt; 1723 1724 assert(!SValOffsets.empty() && "getElementRegionOffsets guarantees the " 1725 "offsets vector is not empty."); 1726 1727 // Check if the containing array has an initialized value that we can trust. 1728 // We can trust a const value or a value of a global initializer in main(). 1729 const VarDecl *VD = VR->getDecl(); 1730 if (!VD->getType().isConstQualified() && 1731 !R->getElementType().isConstQualified() && 1732 (!B.isMainAnalysis() || !VD->hasGlobalStorage())) 1733 return std::nullopt; 1734 1735 // Array's declaration should have `ConstantArrayType` type, because only this 1736 // type contains an array extent. It may happen that array type can be of 1737 // `IncompleteArrayType` type. To get the declaration of `ConstantArrayType` 1738 // type, we should find the declaration in the redeclarations chain that has 1739 // the initialization expression. 1740 // NOTE: `getAnyInitializer` has an out-parameter, which returns a new `VD` 1741 // from which an initializer is obtained. We replace current `VD` with the new 1742 // `VD`. If the return value of the function is null than `VD` won't be 1743 // replaced. 1744 const Expr *Init = VD->getAnyInitializer(VD); 1745 // NOTE: If `Init` is non-null, then a new `VD` is non-null for sure. So check 1746 // `Init` for null only and don't worry about the replaced `VD`. 1747 if (!Init) 1748 return std::nullopt; 1749 1750 // Array's declaration should have ConstantArrayType type, because only this 1751 // type contains an array extent. 1752 const ConstantArrayType *CAT = Ctx.getAsConstantArrayType(VD->getType()); 1753 if (!CAT) 1754 return std::nullopt; 1755 1756 // Get array extents. 1757 SmallVector<uint64_t, 2> Extents = getConstantArrayExtents(CAT); 1758 1759 // The number of offsets should equal to the numbers of extents, 1760 // otherwise wrong type punning occurred. For instance: 1761 // int arr[1][2][3]; 1762 // auto ptr = (int(*)[42])arr; 1763 // auto x = ptr[4][2]; // UB 1764 // FIXME: Should return UndefinedVal. 1765 if (SValOffsets.size() != Extents.size()) 1766 return std::nullopt; 1767 1768 SmallVector<uint64_t, 2> ConcreteOffsets; 1769 if (std::optional<SVal> V = convertOffsetsFromSvalToUnsigneds( 1770 SValOffsets, Extents, ConcreteOffsets)) 1771 return *V; 1772 1773 // Handle InitListExpr. 1774 // Example: 1775 // const char arr[4][2] = { { 1, 2 }, { 3 }, 4, 5 }; 1776 if (const auto *ILE = dyn_cast<InitListExpr>(Init)) 1777 return getSValFromInitListExpr(ILE, ConcreteOffsets, R->getElementType()); 1778 1779 // Handle StringLiteral. 1780 // Example: 1781 // const char arr[] = "abc"; 1782 if (const auto *SL = dyn_cast<StringLiteral>(Init)) 1783 return getSValFromStringLiteral(SL, ConcreteOffsets.front(), 1784 R->getElementType()); 1785 1786 // FIXME: Handle CompoundLiteralExpr. 1787 1788 return std::nullopt; 1789} 1790 1791/// Returns an SVal, if possible, for the specified position of an 1792/// initialization list. 1793/// 1794/// \param ILE The given initialization list. 1795/// \param Offsets The array of unsigned offsets. E.g. for the expression 1796/// `int x = arr[1][2][3];` an array should be { 1, 2, 3 }. 1797/// \param ElemT The type of the result SVal expression. 1798/// \return Optional SVal for the particular position in the initialization 1799/// list. E.g. for the list `{{1, 2},[3, 4],{5, 6}, {}}` offsets: 1800/// - {1, 1} returns SVal{4}, because it's the second position in the second 1801/// sublist; 1802/// - {3, 0} returns SVal{0}, because there's no explicit value at this 1803/// position in the sublist. 1804/// 1805/// NOTE: Inorder to get a valid SVal, a caller shall guarantee valid offsets 1806/// for the given initialization list. Otherwise SVal can be an equivalent to 0 1807/// or lead to assertion. 1808std::optional<SVal> RegionStoreManager::getSValFromInitListExpr( 1809 const InitListExpr *ILE, const SmallVector<uint64_t, 2> &Offsets, 1810 QualType ElemT) { 1811 assert(ILE && "InitListExpr should not be null"); 1812 1813 for (uint64_t Offset : Offsets) { 1814 // C++20 [dcl.init.string] 9.4.2.1: 1815 // An array of ordinary character type [...] can be initialized by [...] 1816 // an appropriately-typed string-literal enclosed in braces. 1817 // Example: 1818 // const char arr[] = { "abc" }; 1819 if (ILE->isStringLiteralInit()) 1820 if (const auto *SL = dyn_cast<StringLiteral>(ILE->getInit(0))) 1821 return getSValFromStringLiteral(SL, Offset, ElemT); 1822 1823 // C++20 [expr.add] 9.4.17.5 (excerpt): 1824 // i-th array element is value-initialized for each k < i ��� n, 1825 // where k is an expression-list size and n is an array extent. 1826 if (Offset >= ILE->getNumInits()) 1827 return svalBuilder.makeZeroVal(ElemT); 1828 1829 const Expr *E = ILE->getInit(Offset); 1830 const auto *IL = dyn_cast<InitListExpr>(E); 1831 if (!IL) 1832 // Return a constant value, if it is presented. 1833 // FIXME: Support other SVals. 1834 return svalBuilder.getConstantVal(E); 1835 1836 // Go to the nested initializer list. 1837 ILE = IL; 1838 } 1839 1840 assert(ILE); 1841 1842 // FIXME: Unhandeled InitListExpr sub-expression, possibly constructing an 1843 // enum? 1844 return std::nullopt; 1845} 1846 1847/// Returns an SVal, if possible, for the specified position in a string 1848/// literal. 1849/// 1850/// \param SL The given string literal. 1851/// \param Offset The unsigned offset. E.g. for the expression 1852/// `char x = str[42];` an offset should be 42. 1853/// E.g. for the string "abc" offset: 1854/// - 1 returns SVal{b}, because it's the second position in the string. 1855/// - 42 returns SVal{0}, because there's no explicit value at this 1856/// position in the string. 1857/// \param ElemT The type of the result SVal expression. 1858/// 1859/// NOTE: We return `0` for every offset >= the literal length for array 1860/// declarations, like: 1861/// const char str[42] = "123"; // Literal length is 4. 1862/// char c = str[41]; // Offset is 41. 1863/// FIXME: Nevertheless, we can't do the same for pointer declaraions, like: 1864/// const char * const str = "123"; // Literal length is 4. 1865/// char c = str[41]; // Offset is 41. Returns `0`, but Undef 1866/// // expected. 1867/// It should be properly handled before reaching this point. 1868/// The main problem is that we can't distinguish between these declarations, 1869/// because in case of array we can get the Decl from VarRegion, but in case 1870/// of pointer the region is a StringRegion, which doesn't contain a Decl. 1871/// Possible solution could be passing an array extent along with the offset. 1872SVal RegionStoreManager::getSValFromStringLiteral(const StringLiteral *SL, 1873 uint64_t Offset, 1874 QualType ElemT) { 1875 assert(SL && "StringLiteral should not be null"); 1876 // C++20 [dcl.init.string] 9.4.2.3: 1877 // If there are fewer initializers than there are array elements, each 1878 // element not explicitly initialized shall be zero-initialized [dcl.init]. 1879 uint32_t Code = (Offset >= SL->getLength()) ? 0 : SL->getCodeUnit(Offset); 1880 return svalBuilder.makeIntVal(Code, ElemT); 1881} 1882 1883static std::optional<SVal> getDerivedSymbolForBinding( 1884 RegionBindingsConstRef B, const TypedValueRegion *BaseRegion, 1885 const TypedValueRegion *SubReg, const ASTContext &Ctx, SValBuilder &SVB) { 1886 assert(BaseRegion); 1887 QualType BaseTy = BaseRegion->getValueType(); 1888 QualType Ty = SubReg->getValueType(); 1889 if (BaseTy->isScalarType() && Ty->isScalarType()) { 1890 if (Ctx.getTypeSizeInChars(BaseTy) >= Ctx.getTypeSizeInChars(Ty)) { 1891 if (const std::optional<SVal> &ParentValue = 1892 B.getDirectBinding(BaseRegion)) { 1893 if (SymbolRef ParentValueAsSym = ParentValue->getAsSymbol()) 1894 return SVB.getDerivedRegionValueSymbolVal(ParentValueAsSym, SubReg); 1895 1896 if (ParentValue->isUndef()) 1897 return UndefinedVal(); 1898 1899 // Other cases: give up. We are indexing into a larger object 1900 // that has some value, but we don't know how to handle that yet. 1901 return UnknownVal(); 1902 } 1903 } 1904 } 1905 return std::nullopt; 1906} 1907 1908SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B, 1909 const ElementRegion* R) { 1910 // Check if the region has a binding. 1911 if (const std::optional<SVal> &V = B.getDirectBinding(R)) 1912 return *V; 1913 1914 const MemRegion* superR = R->getSuperRegion(); 1915 1916 // Check if the region is an element region of a string literal. 1917 if (const StringRegion *StrR = dyn_cast<StringRegion>(superR)) { 1918 // FIXME: Handle loads from strings where the literal is treated as 1919 // an integer, e.g., *((unsigned int*)"hello"). Such loads are UB according 1920 // to C++20 7.2.1.11 [basic.lval]. 1921 QualType T = Ctx.getAsArrayType(StrR->getValueType())->getElementType(); 1922 if (!Ctx.hasSameUnqualifiedType(T, R->getElementType())) 1923 return UnknownVal(); 1924 if (const auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) { 1925 const llvm::APSInt &Idx = CI->getValue(); 1926 if (Idx < 0) 1927 return UndefinedVal(); 1928 const StringLiteral *SL = StrR->getStringLiteral(); 1929 return getSValFromStringLiteral(SL, Idx.getZExtValue(), T); 1930 } 1931 } else if (isa<ElementRegion, VarRegion>(superR)) { 1932 if (std::optional<SVal> V = getConstantValFromConstArrayInitializer(B, R)) 1933 return *V; 1934 } 1935 1936 // Check for loads from a code text region. For such loads, just give up. 1937 if (isa<CodeTextRegion>(superR)) 1938 return UnknownVal(); 1939 1940 // Handle the case where we are indexing into a larger scalar object. 1941 // For example, this handles: 1942 // int x = ... 1943 // char *y = &x; 1944 // return *y; 1945 // FIXME: This is a hack, and doesn't do anything really intelligent yet. 1946 const RegionRawOffset &O = R->getAsArrayOffset(); 1947 1948 // If we cannot reason about the offset, return an unknown value. 1949 if (!O.getRegion()) 1950 return UnknownVal(); 1951 1952 if (const TypedValueRegion *baseR = dyn_cast<TypedValueRegion>(O.getRegion())) 1953 if (auto V = getDerivedSymbolForBinding(B, baseR, R, Ctx, svalBuilder)) 1954 return *V; 1955 1956 return getBindingForFieldOrElementCommon(B, R, R->getElementType()); 1957} 1958 1959SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B, 1960 const FieldRegion* R) { 1961 1962 // Check if the region has a binding. 1963 if (const std::optional<SVal> &V = B.getDirectBinding(R)) 1964 return *V; 1965 1966 // If the containing record was initialized, try to get its constant value. 1967 const FieldDecl *FD = R->getDecl(); 1968 QualType Ty = FD->getType(); 1969 const MemRegion* superR = R->getSuperRegion(); 1970 if (const auto *VR = dyn_cast<VarRegion>(superR)) { 1971 const VarDecl *VD = VR->getDecl(); 1972 QualType RecordVarTy = VD->getType(); 1973 unsigned Index = FD->getFieldIndex(); 1974 // Either the record variable or the field has an initializer that we can 1975 // trust. We trust initializers of constants and, additionally, respect 1976 // initializers of globals when analyzing main(). 1977 if (RecordVarTy.isConstQualified() || Ty.isConstQualified() || 1978 (B.isMainAnalysis() && VD->hasGlobalStorage())) 1979 if (const Expr *Init = VD->getAnyInitializer()) 1980 if (const auto *InitList = dyn_cast<InitListExpr>(Init)) { 1981 if (Index < InitList->getNumInits()) { 1982 if (const Expr *FieldInit = InitList->getInit(Index)) 1983 if (std::optional<SVal> V = svalBuilder.getConstantVal(FieldInit)) 1984 return *V; 1985 } else { 1986 return svalBuilder.makeZeroVal(Ty); 1987 } 1988 } 1989 } 1990 1991 // Handle the case where we are accessing into a larger scalar object. 1992 // For example, this handles: 1993 // struct header { 1994 // unsigned a : 1; 1995 // unsigned b : 1; 1996 // }; 1997 // struct parse_t { 1998 // unsigned bits0 : 1; 1999 // unsigned bits2 : 2; // <-- header 2000 // unsigned bits4 : 4; 2001 // }; 2002 // int parse(parse_t *p) { 2003 // unsigned copy = p->bits2; 2004 // header *bits = (header *)© 2005 // return bits->b; <-- here 2006 // } 2007 if (const auto *Base = dyn_cast<TypedValueRegion>(R->getBaseRegion())) 2008 if (auto V = getDerivedSymbolForBinding(B, Base, R, Ctx, svalBuilder)) 2009 return *V; 2010 2011 return getBindingForFieldOrElementCommon(B, R, Ty); 2012} 2013 2014std::optional<SVal> RegionStoreManager::getBindingForDerivedDefaultValue( 2015 RegionBindingsConstRef B, const MemRegion *superR, 2016 const TypedValueRegion *R, QualType Ty) { 2017 2018 if (const std::optional<SVal> &D = B.getDefaultBinding(superR)) { 2019 SVal val = *D; 2020 if (SymbolRef parentSym = val.getAsSymbol()) 2021 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 2022 2023 if (val.isZeroConstant()) 2024 return svalBuilder.makeZeroVal(Ty); 2025 2026 if (val.isUnknownOrUndef()) 2027 return val; 2028 2029 // Lazy bindings are usually handled through getExistingLazyBinding(). 2030 // We should unify these two code paths at some point. 2031 if (isa<nonloc::LazyCompoundVal, nonloc::CompoundVal>(val)) 2032 return val; 2033 2034 llvm_unreachable("Unknown default value"); 2035 } 2036 2037 return std::nullopt; 2038} 2039 2040SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion, 2041 RegionBindingsRef LazyBinding) { 2042 SVal Result; 2043 if (const ElementRegion *ER = dyn_cast<ElementRegion>(LazyBindingRegion)) 2044 Result = getBindingForElement(LazyBinding, ER); 2045 else 2046 Result = getBindingForField(LazyBinding, 2047 cast<FieldRegion>(LazyBindingRegion)); 2048 2049 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 2050 // default value for /part/ of an aggregate from a default value for the 2051 // /entire/ aggregate. The most common case of this is when struct Outer 2052 // has as its first member a struct Inner, which is copied in from a stack 2053 // variable. In this case, even if the Outer's default value is symbolic, 0, 2054 // or unknown, it gets overridden by the Inner's default value of undefined. 2055 // 2056 // This is a general problem -- if the Inner is zero-initialized, the Outer 2057 // will now look zero-initialized. The proper way to solve this is with a 2058 // new version of RegionStore that tracks the extent of a binding as well 2059 // as the offset. 2060 // 2061 // This hack only takes care of the undefined case because that can very 2062 // quickly result in a warning. 2063 if (Result.isUndef()) 2064 Result = UnknownVal(); 2065 2066 return Result; 2067} 2068 2069SVal 2070RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B, 2071 const TypedValueRegion *R, 2072 QualType Ty) { 2073 2074 // At this point we have already checked in either getBindingForElement or 2075 // getBindingForField if 'R' has a direct binding. 2076 2077 // Lazy binding? 2078 Store lazyBindingStore = nullptr; 2079 const SubRegion *lazyBindingRegion = nullptr; 2080 std::tie(lazyBindingStore, lazyBindingRegion) = findLazyBinding(B, R, R); 2081 if (lazyBindingRegion) 2082 return getLazyBinding(lazyBindingRegion, 2083 getRegionBindings(lazyBindingStore)); 2084 2085 // Record whether or not we see a symbolic index. That can completely 2086 // be out of scope of our lookup. 2087 bool hasSymbolicIndex = false; 2088 2089 // FIXME: This is a hack to deal with RegionStore's inability to distinguish a 2090 // default value for /part/ of an aggregate from a default value for the 2091 // /entire/ aggregate. The most common case of this is when struct Outer 2092 // has as its first member a struct Inner, which is copied in from a stack 2093 // variable. In this case, even if the Outer's default value is symbolic, 0, 2094 // or unknown, it gets overridden by the Inner's default value of undefined. 2095 // 2096 // This is a general problem -- if the Inner is zero-initialized, the Outer 2097 // will now look zero-initialized. The proper way to solve this is with a 2098 // new version of RegionStore that tracks the extent of a binding as well 2099 // as the offset. 2100 // 2101 // This hack only takes care of the undefined case because that can very 2102 // quickly result in a warning. 2103 bool hasPartialLazyBinding = false; 2104 2105 const SubRegion *SR = R; 2106 while (SR) { 2107 const MemRegion *Base = SR->getSuperRegion(); 2108 if (std::optional<SVal> D = 2109 getBindingForDerivedDefaultValue(B, Base, R, Ty)) { 2110 if (D->getAs<nonloc::LazyCompoundVal>()) { 2111 hasPartialLazyBinding = true; 2112 break; 2113 } 2114 2115 return *D; 2116 } 2117 2118 if (const ElementRegion *ER = dyn_cast<ElementRegion>(Base)) { 2119 NonLoc index = ER->getIndex(); 2120 if (!index.isConstant()) 2121 hasSymbolicIndex = true; 2122 } 2123 2124 // If our super region is a field or element itself, walk up the region 2125 // hierarchy to see if there is a default value installed in an ancestor. 2126 SR = dyn_cast<SubRegion>(Base); 2127 } 2128 2129 if (R->hasStackNonParametersStorage()) { 2130 if (isa<ElementRegion>(R)) { 2131 // Currently we don't reason specially about Clang-style vectors. Check 2132 // if superR is a vector and if so return Unknown. 2133 if (const TypedValueRegion *typedSuperR = 2134 dyn_cast<TypedValueRegion>(R->getSuperRegion())) { 2135 if (typedSuperR->getValueType()->isVectorType()) 2136 return UnknownVal(); 2137 } 2138 } 2139 2140 // FIXME: We also need to take ElementRegions with symbolic indexes into 2141 // account. This case handles both directly accessing an ElementRegion 2142 // with a symbolic offset, but also fields within an element with 2143 // a symbolic offset. 2144 if (hasSymbolicIndex) 2145 return UnknownVal(); 2146 2147 // Additionally allow introspection of a block's internal layout. 2148 // Try to get direct binding if all other attempts failed thus far. 2149 // Else, return UndefinedVal() 2150 if (!hasPartialLazyBinding && !isa<BlockDataRegion>(R->getBaseRegion())) { 2151 if (const std::optional<SVal> &V = B.getDefaultBinding(R)) 2152 return *V; 2153 return UndefinedVal(); 2154 } 2155 } 2156 2157 // All other values are symbolic. 2158 return svalBuilder.getRegionValueSymbolVal(R); 2159} 2160 2161SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B, 2162 const ObjCIvarRegion* R) { 2163 // Check if the region has a binding. 2164 if (const std::optional<SVal> &V = B.getDirectBinding(R)) 2165 return *V; 2166 2167 const MemRegion *superR = R->getSuperRegion(); 2168 2169 // Check if the super region has a default binding. 2170 if (const std::optional<SVal> &V = B.getDefaultBinding(superR)) { 2171 if (SymbolRef parentSym = V->getAsSymbol()) 2172 return svalBuilder.getDerivedRegionValueSymbolVal(parentSym, R); 2173 2174 // Other cases: give up. 2175 return UnknownVal(); 2176 } 2177 2178 return getBindingForLazySymbol(R); 2179} 2180 2181SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B, 2182 const VarRegion *R) { 2183 2184 // Check if the region has a binding. 2185 if (std::optional<SVal> V = B.getDirectBinding(R)) 2186 return *V; 2187 2188 if (std::optional<SVal> V = B.getDefaultBinding(R)) 2189 return *V; 2190 2191 // Lazily derive a value for the VarRegion. 2192 const VarDecl *VD = R->getDecl(); 2193 const MemSpaceRegion *MS = R->getMemorySpace(); 2194 2195 // Arguments are always symbolic. 2196 if (isa<StackArgumentsSpaceRegion>(MS)) 2197 return svalBuilder.getRegionValueSymbolVal(R); 2198 2199 // Is 'VD' declared constant? If so, retrieve the constant value. 2200 if (VD->getType().isConstQualified()) { 2201 if (const Expr *Init = VD->getAnyInitializer()) { 2202 if (std::optional<SVal> V = svalBuilder.getConstantVal(Init)) 2203 return *V; 2204 2205 // If the variable is const qualified and has an initializer but 2206 // we couldn't evaluate initializer to a value, treat the value as 2207 // unknown. 2208 return UnknownVal(); 2209 } 2210 } 2211 2212 // This must come after the check for constants because closure-captured 2213 // constant variables may appear in UnknownSpaceRegion. 2214 if (isa<UnknownSpaceRegion>(MS)) 2215 return svalBuilder.getRegionValueSymbolVal(R); 2216 2217 if (isa<GlobalsSpaceRegion>(MS)) { 2218 QualType T = VD->getType(); 2219 2220 // If we're in main(), then global initializers have not become stale yet. 2221 if (B.isMainAnalysis()) 2222 if (const Expr *Init = VD->getAnyInitializer()) 2223 if (std::optional<SVal> V = svalBuilder.getConstantVal(Init)) 2224 return *V; 2225 2226 // Function-scoped static variables are default-initialized to 0; if they 2227 // have an initializer, it would have been processed by now. 2228 // FIXME: This is only true when we're starting analysis from main(). 2229 // We're losing a lot of coverage here. 2230 if (isa<StaticGlobalSpaceRegion>(MS)) 2231 return svalBuilder.makeZeroVal(T); 2232 2233 if (std::optional<SVal> V = getBindingForDerivedDefaultValue(B, MS, R, T)) { 2234 assert(!V->getAs<nonloc::LazyCompoundVal>()); 2235 return *V; 2236 } 2237 2238 return svalBuilder.getRegionValueSymbolVal(R); 2239 } 2240 2241 return UndefinedVal(); 2242} 2243 2244SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) { 2245 // All other values are symbolic. 2246 return svalBuilder.getRegionValueSymbolVal(R); 2247} 2248 2249const RegionStoreManager::SValListTy & 2250RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) { 2251 // First, check the cache. 2252 LazyBindingsMapTy::iterator I = LazyBindingsMap.find(LCV.getCVData()); 2253 if (I != LazyBindingsMap.end()) 2254 return I->second; 2255 2256 // If we don't have a list of values cached, start constructing it. 2257 SValListTy List; 2258 2259 const SubRegion *LazyR = LCV.getRegion(); 2260 RegionBindingsRef B = getRegionBindings(LCV.getStore()); 2261 2262 // If this region had /no/ bindings at the time, there are no interesting 2263 // values to return. 2264 const ClusterBindings *Cluster = B.lookup(LazyR->getBaseRegion()); 2265 if (!Cluster) 2266 return (LazyBindingsMap[LCV.getCVData()] = std::move(List)); 2267 2268 SmallVector<BindingPair, 32> Bindings; 2269 collectSubRegionBindings(Bindings, svalBuilder, *Cluster, LazyR, 2270 /*IncludeAllDefaultBindings=*/true); 2271 for (SVal V : llvm::make_second_range(Bindings)) { 2272 if (V.isUnknownOrUndef() || V.isConstant()) 2273 continue; 2274 2275 if (auto InnerLCV = V.getAs<nonloc::LazyCompoundVal>()) { 2276 const SValListTy &InnerList = getInterestingValues(*InnerLCV); 2277 List.insert(List.end(), InnerList.begin(), InnerList.end()); 2278 } 2279 2280 List.push_back(V); 2281 } 2282 2283 return (LazyBindingsMap[LCV.getCVData()] = std::move(List)); 2284} 2285 2286NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B, 2287 const TypedValueRegion *R) { 2288 if (std::optional<nonloc::LazyCompoundVal> V = 2289 getExistingLazyBinding(svalBuilder, B, R, false)) 2290 return *V; 2291 2292 return svalBuilder.makeLazyCompoundVal(StoreRef(B.asStore(), *this), R); 2293} 2294 2295static bool isRecordEmpty(const RecordDecl *RD) { 2296 if (!RD->field_empty()) 2297 return false; 2298 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) 2299 return CRD->getNumBases() == 0; 2300 return true; 2301} 2302 2303SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B, 2304 const TypedValueRegion *R) { 2305 const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl(); 2306 if (!RD->getDefinition() || isRecordEmpty(RD)) 2307 return UnknownVal(); 2308 2309 return createLazyBinding(B, R); 2310} 2311 2312SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B, 2313 const TypedValueRegion *R) { 2314 assert(Ctx.getAsConstantArrayType(R->getValueType()) && 2315 "Only constant array types can have compound bindings."); 2316 2317 return createLazyBinding(B, R); 2318} 2319 2320bool RegionStoreManager::includedInBindings(Store store, 2321 const MemRegion *region) const { 2322 RegionBindingsRef B = getRegionBindings(store); 2323 region = region->getBaseRegion(); 2324 2325 // Quick path: if the base is the head of a cluster, the region is live. 2326 if (B.lookup(region)) 2327 return true; 2328 2329 // Slow path: if the region is the VALUE of any binding, it is live. 2330 for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) { 2331 const ClusterBindings &Cluster = RI.getData(); 2332 for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end(); 2333 CI != CE; ++CI) { 2334 SVal D = CI.getData(); 2335 if (const MemRegion *R = D.getAsRegion()) 2336 if (R->getBaseRegion() == region) 2337 return true; 2338 } 2339 } 2340 2341 return false; 2342} 2343 2344//===----------------------------------------------------------------------===// 2345// Binding values to regions. 2346//===----------------------------------------------------------------------===// 2347 2348StoreRef RegionStoreManager::killBinding(Store ST, Loc L) { 2349 if (std::optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>()) 2350 if (const MemRegion* R = LV->getRegion()) 2351 return StoreRef(getRegionBindings(ST).removeBinding(R) 2352 .asImmutableMap() 2353 .getRootWithoutRetain(), 2354 *this); 2355 2356 return StoreRef(ST, *this); 2357} 2358 2359RegionBindingsRef 2360RegionStoreManager::bind(RegionBindingsConstRef B, Loc L, SVal V) { 2361 if (L.getAs<loc::ConcreteInt>()) 2362 return B; 2363 2364 // If we get here, the location should be a region. 2365 const MemRegion *R = L.castAs<loc::MemRegionVal>().getRegion(); 2366 2367 // Check if the region is a struct region. 2368 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(R)) { 2369 QualType Ty = TR->getValueType(); 2370 if (Ty->isArrayType()) 2371 return bindArray(B, TR, V); 2372 if (Ty->isStructureOrClassType()) 2373 return bindStruct(B, TR, V); 2374 if (Ty->isVectorType()) 2375 return bindVector(B, TR, V); 2376 if (Ty->isUnionType()) 2377 return bindAggregate(B, TR, V); 2378 } 2379 2380 // Binding directly to a symbolic region should be treated as binding 2381 // to element 0. 2382 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 2383 R = GetElementZeroRegion(SR, SR->getPointeeStaticType()); 2384 2385 assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) && 2386 "'this' pointer is not an l-value and is not assignable"); 2387 2388 // Clear out bindings that may overlap with this binding. 2389 RegionBindingsRef NewB = removeSubRegionBindings(B, cast<SubRegion>(R)); 2390 2391 // LazyCompoundVals should be always bound as 'default' bindings. 2392 auto KeyKind = isa<nonloc::LazyCompoundVal>(V) ? BindingKey::Default 2393 : BindingKey::Direct; 2394 return NewB.addBinding(BindingKey::Make(R, KeyKind), V); 2395} 2396 2397RegionBindingsRef 2398RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B, 2399 const MemRegion *R, 2400 QualType T) { 2401 SVal V; 2402 2403 if (Loc::isLocType(T)) 2404 V = svalBuilder.makeNullWithType(T); 2405 else if (T->isIntegralOrEnumerationType()) 2406 V = svalBuilder.makeZeroVal(T); 2407 else if (T->isStructureOrClassType() || T->isArrayType()) { 2408 // Set the default value to a zero constant when it is a structure 2409 // or array. The type doesn't really matter. 2410 V = svalBuilder.makeZeroVal(Ctx.IntTy); 2411 } 2412 else { 2413 // We can't represent values of this type, but we still need to set a value 2414 // to record that the region has been initialized. 2415 // If this assertion ever fires, a new case should be added above -- we 2416 // should know how to default-initialize any value we can symbolicate. 2417 assert(!SymbolManager::canSymbolicate(T) && "This type is representable"); 2418 V = UnknownVal(); 2419 } 2420 2421 return B.addBinding(R, BindingKey::Default, V); 2422} 2423 2424std::optional<RegionBindingsRef> RegionStoreManager::tryBindSmallArray( 2425 RegionBindingsConstRef B, const TypedValueRegion *R, const ArrayType *AT, 2426 nonloc::LazyCompoundVal LCV) { 2427 2428 auto CAT = dyn_cast<ConstantArrayType>(AT); 2429 2430 // If we don't know the size, create a lazyCompoundVal instead. 2431 if (!CAT) 2432 return std::nullopt; 2433 2434 QualType Ty = CAT->getElementType(); 2435 if (!(Ty->isScalarType() || Ty->isReferenceType())) 2436 return std::nullopt; 2437 2438 // If the array is too big, create a LCV instead. 2439 uint64_t ArrSize = CAT->getSize().getLimitedValue(); 2440 if (ArrSize > SmallArrayLimit) 2441 return std::nullopt; 2442 2443 RegionBindingsRef NewB = B; 2444 2445 for (uint64_t i = 0; i < ArrSize; ++i) { 2446 auto Idx = svalBuilder.makeArrayIndex(i); 2447 const ElementRegion *SrcER = 2448 MRMgr.getElementRegion(Ty, Idx, LCV.getRegion(), Ctx); 2449 SVal V = getBindingForElement(getRegionBindings(LCV.getStore()), SrcER); 2450 2451 const ElementRegion *DstER = MRMgr.getElementRegion(Ty, Idx, R, Ctx); 2452 NewB = bind(NewB, loc::MemRegionVal(DstER), V); 2453 } 2454 2455 return NewB; 2456} 2457 2458RegionBindingsRef 2459RegionStoreManager::bindArray(RegionBindingsConstRef B, 2460 const TypedValueRegion* R, 2461 SVal Init) { 2462 2463 const ArrayType *AT =cast<ArrayType>(Ctx.getCanonicalType(R->getValueType())); 2464 QualType ElementTy = AT->getElementType(); 2465 std::optional<uint64_t> Size; 2466 2467 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT)) 2468 Size = CAT->getSize().getZExtValue(); 2469 2470 // Check if the init expr is a literal. If so, bind the rvalue instead. 2471 // FIXME: It's not responsibility of the Store to transform this lvalue 2472 // to rvalue. ExprEngine or maybe even CFG should do this before binding. 2473 if (std::optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) { 2474 SVal V = getBinding(B.asStore(), *MRV, R->getValueType()); 2475 return bindAggregate(B, R, V); 2476 } 2477 2478 // Handle lazy compound values. 2479 if (std::optional<nonloc::LazyCompoundVal> LCV = 2480 Init.getAs<nonloc::LazyCompoundVal>()) { 2481 if (std::optional<RegionBindingsRef> NewB = 2482 tryBindSmallArray(B, R, AT, *LCV)) 2483 return *NewB; 2484 2485 return bindAggregate(B, R, Init); 2486 } 2487 2488 if (Init.isUnknown()) 2489 return bindAggregate(B, R, UnknownVal()); 2490 2491 // Remaining case: explicit compound values. 2492 const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>(); 2493 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2494 uint64_t i = 0; 2495 2496 RegionBindingsRef NewB(B); 2497 2498 for (; Size ? i < *Size : true; ++i, ++VI) { 2499 // The init list might be shorter than the array length. 2500 if (VI == VE) 2501 break; 2502 2503 NonLoc Idx = svalBuilder.makeArrayIndex(i); 2504 const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, Ctx); 2505 2506 if (ElementTy->isStructureOrClassType()) 2507 NewB = bindStruct(NewB, ER, *VI); 2508 else if (ElementTy->isArrayType()) 2509 NewB = bindArray(NewB, ER, *VI); 2510 else 2511 NewB = bind(NewB, loc::MemRegionVal(ER), *VI); 2512 } 2513 2514 // If the init list is shorter than the array length (or the array has 2515 // variable length), set the array default value. Values that are already set 2516 // are not overwritten. 2517 if (!Size || i < *Size) 2518 NewB = setImplicitDefaultValue(NewB, R, ElementTy); 2519 2520 return NewB; 2521} 2522 2523RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B, 2524 const TypedValueRegion* R, 2525 SVal V) { 2526 QualType T = R->getValueType(); 2527 const VectorType *VT = T->castAs<VectorType>(); // Use castAs for typedefs. 2528 2529 // Handle lazy compound values and symbolic values. 2530 if (isa<nonloc::LazyCompoundVal, nonloc::SymbolVal>(V)) 2531 return bindAggregate(B, R, V); 2532 2533 // We may get non-CompoundVal accidentally due to imprecise cast logic or 2534 // that we are binding symbolic struct value. Kill the field values, and if 2535 // the value is symbolic go and bind it as a "default" binding. 2536 if (!isa<nonloc::CompoundVal>(V)) { 2537 return bindAggregate(B, R, UnknownVal()); 2538 } 2539 2540 QualType ElemType = VT->getElementType(); 2541 nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>(); 2542 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2543 unsigned index = 0, numElements = VT->getNumElements(); 2544 RegionBindingsRef NewB(B); 2545 2546 for ( ; index != numElements ; ++index) { 2547 if (VI == VE) 2548 break; 2549 2550 NonLoc Idx = svalBuilder.makeArrayIndex(index); 2551 const ElementRegion *ER = MRMgr.getElementRegion(ElemType, Idx, R, Ctx); 2552 2553 if (ElemType->isArrayType()) 2554 NewB = bindArray(NewB, ER, *VI); 2555 else if (ElemType->isStructureOrClassType()) 2556 NewB = bindStruct(NewB, ER, *VI); 2557 else 2558 NewB = bind(NewB, loc::MemRegionVal(ER), *VI); 2559 } 2560 return NewB; 2561} 2562 2563std::optional<RegionBindingsRef> RegionStoreManager::tryBindSmallStruct( 2564 RegionBindingsConstRef B, const TypedValueRegion *R, const RecordDecl *RD, 2565 nonloc::LazyCompoundVal LCV) { 2566 FieldVector Fields; 2567 2568 if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(RD)) 2569 if (Class->getNumBases() != 0 || Class->getNumVBases() != 0) 2570 return std::nullopt; 2571 2572 for (const auto *FD : RD->fields()) { 2573 if (FD->isUnnamedBitfield()) 2574 continue; 2575 2576 // If there are too many fields, or if any of the fields are aggregates, 2577 // just use the LCV as a default binding. 2578 if (Fields.size() == SmallStructLimit) 2579 return std::nullopt; 2580 2581 QualType Ty = FD->getType(); 2582 2583 // Zero length arrays are basically no-ops, so we also ignore them here. 2584 if (Ty->isConstantArrayType() && 2585 Ctx.getConstantArrayElementCount(Ctx.getAsConstantArrayType(Ty)) == 0) 2586 continue; 2587 2588 if (!(Ty->isScalarType() || Ty->isReferenceType())) 2589 return std::nullopt; 2590 2591 Fields.push_back(FD); 2592 } 2593 2594 RegionBindingsRef NewB = B; 2595 2596 for (const FieldDecl *Field : Fields) { 2597 const FieldRegion *SourceFR = MRMgr.getFieldRegion(Field, LCV.getRegion()); 2598 SVal V = getBindingForField(getRegionBindings(LCV.getStore()), SourceFR); 2599 2600 const FieldRegion *DestFR = MRMgr.getFieldRegion(Field, R); 2601 NewB = bind(NewB, loc::MemRegionVal(DestFR), V); 2602 } 2603 2604 return NewB; 2605} 2606 2607RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B, 2608 const TypedValueRegion *R, 2609 SVal V) { 2610 QualType T = R->getValueType(); 2611 assert(T->isStructureOrClassType()); 2612 2613 const RecordType* RT = T->castAs<RecordType>(); 2614 const RecordDecl *RD = RT->getDecl(); 2615 2616 if (!RD->isCompleteDefinition()) 2617 return B; 2618 2619 // Handle lazy compound values and symbolic values. 2620 if (std::optional<nonloc::LazyCompoundVal> LCV = 2621 V.getAs<nonloc::LazyCompoundVal>()) { 2622 if (std::optional<RegionBindingsRef> NewB = 2623 tryBindSmallStruct(B, R, RD, *LCV)) 2624 return *NewB; 2625 return bindAggregate(B, R, V); 2626 } 2627 if (isa<nonloc::SymbolVal>(V)) 2628 return bindAggregate(B, R, V); 2629 2630 // We may get non-CompoundVal accidentally due to imprecise cast logic or 2631 // that we are binding symbolic struct value. Kill the field values, and if 2632 // the value is symbolic go and bind it as a "default" binding. 2633 if (V.isUnknown() || !isa<nonloc::CompoundVal>(V)) 2634 return bindAggregate(B, R, UnknownVal()); 2635 2636 // The raw CompoundVal is essentially a symbolic InitListExpr: an (immutable) 2637 // list of other values. It appears pretty much only when there's an actual 2638 // initializer list expression in the program, and the analyzer tries to 2639 // unwrap it as soon as possible. 2640 // This code is where such unwrap happens: when the compound value is put into 2641 // the object that it was supposed to initialize (it's an *initializer* list, 2642 // after all), instead of binding the whole value to the whole object, we bind 2643 // sub-values to sub-objects. Sub-values may themselves be compound values, 2644 // and in this case the procedure becomes recursive. 2645 // FIXME: The annoying part about compound values is that they don't carry 2646 // any sort of information about which value corresponds to which sub-object. 2647 // It's simply a list of values in the middle of nowhere; we expect to match 2648 // them to sub-objects, essentially, "by index": first value binds to 2649 // the first field, second value binds to the second field, etc. 2650 // It would have been much safer to organize non-lazy compound values as 2651 // a mapping from fields/bases to values. 2652 const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>(); 2653 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end(); 2654 2655 RegionBindingsRef NewB(B); 2656 2657 // In C++17 aggregates may have base classes, handle those as well. 2658 // They appear before fields in the initializer list / compound value. 2659 if (const auto *CRD = dyn_cast<CXXRecordDecl>(RD)) { 2660 // If the object was constructed with a constructor, its value is a 2661 // LazyCompoundVal. If it's a raw CompoundVal, it means that we're 2662 // performing aggregate initialization. The only exception from this 2663 // rule is sending an Objective-C++ message that returns a C++ object 2664 // to a nil receiver; in this case the semantics is to return a 2665 // zero-initialized object even if it's a C++ object that doesn't have 2666 // this sort of constructor; the CompoundVal is empty in this case. 2667 assert((CRD->isAggregate() || (Ctx.getLangOpts().ObjC && VI == VE)) && 2668 "Non-aggregates are constructed with a constructor!"); 2669 2670 for (const auto &B : CRD->bases()) { 2671 // (Multiple inheritance is fine though.) 2672 assert(!B.isVirtual() && "Aggregates cannot have virtual base classes!"); 2673 2674 if (VI == VE) 2675 break; 2676 2677 QualType BTy = B.getType(); 2678 assert(BTy->isStructureOrClassType() && "Base classes must be classes!"); 2679 2680 const CXXRecordDecl *BRD = BTy->getAsCXXRecordDecl(); 2681 assert(BRD && "Base classes must be C++ classes!"); 2682 2683 const CXXBaseObjectRegion *BR = 2684 MRMgr.getCXXBaseObjectRegion(BRD, R, /*IsVirtual=*/false); 2685 2686 NewB = bindStruct(NewB, BR, *VI); 2687 2688 ++VI; 2689 } 2690 } 2691 2692 RecordDecl::field_iterator FI, FE; 2693 2694 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) { 2695 2696 if (VI == VE) 2697 break; 2698 2699 // Skip any unnamed bitfields to stay in sync with the initializers. 2700 if (FI->isUnnamedBitfield()) 2701 continue; 2702 2703 QualType FTy = FI->getType(); 2704 const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R); 2705 2706 if (FTy->isArrayType()) 2707 NewB = bindArray(NewB, FR, *VI); 2708 else if (FTy->isStructureOrClassType()) 2709 NewB = bindStruct(NewB, FR, *VI); 2710 else 2711 NewB = bind(NewB, loc::MemRegionVal(FR), *VI); 2712 ++VI; 2713 } 2714 2715 // There may be fewer values in the initialize list than the fields of struct. 2716 if (FI != FE) { 2717 NewB = NewB.addBinding(R, BindingKey::Default, 2718 svalBuilder.makeIntVal(0, false)); 2719 } 2720 2721 return NewB; 2722} 2723 2724RegionBindingsRef 2725RegionStoreManager::bindAggregate(RegionBindingsConstRef B, 2726 const TypedRegion *R, 2727 SVal Val) { 2728 // Remove the old bindings, using 'R' as the root of all regions 2729 // we will invalidate. Then add the new binding. 2730 return removeSubRegionBindings(B, R).addBinding(R, BindingKey::Default, Val); 2731} 2732 2733//===----------------------------------------------------------------------===// 2734// State pruning. 2735//===----------------------------------------------------------------------===// 2736 2737namespace { 2738class RemoveDeadBindingsWorker 2739 : public ClusterAnalysis<RemoveDeadBindingsWorker> { 2740 SmallVector<const SymbolicRegion *, 12> Postponed; 2741 SymbolReaper &SymReaper; 2742 const StackFrameContext *CurrentLCtx; 2743 2744public: 2745 RemoveDeadBindingsWorker(RegionStoreManager &rm, 2746 ProgramStateManager &stateMgr, 2747 RegionBindingsRef b, SymbolReaper &symReaper, 2748 const StackFrameContext *LCtx) 2749 : ClusterAnalysis<RemoveDeadBindingsWorker>(rm, stateMgr, b), 2750 SymReaper(symReaper), CurrentLCtx(LCtx) {} 2751 2752 // Called by ClusterAnalysis. 2753 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C); 2754 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C); 2755 using ClusterAnalysis<RemoveDeadBindingsWorker>::VisitCluster; 2756 2757 using ClusterAnalysis::AddToWorkList; 2758 2759 bool AddToWorkList(const MemRegion *R); 2760 2761 bool UpdatePostponed(); 2762 void VisitBinding(SVal V); 2763}; 2764} 2765 2766bool RemoveDeadBindingsWorker::AddToWorkList(const MemRegion *R) { 2767 const MemRegion *BaseR = R->getBaseRegion(); 2768 return AddToWorkList(WorkListElement(BaseR), getCluster(BaseR)); 2769} 2770 2771void RemoveDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR, 2772 const ClusterBindings &C) { 2773 2774 if (const VarRegion *VR = dyn_cast<VarRegion>(baseR)) { 2775 if (SymReaper.isLive(VR)) 2776 AddToWorkList(baseR, &C); 2777 2778 return; 2779 } 2780 2781 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR)) { 2782 if (SymReaper.isLive(SR->getSymbol())) 2783 AddToWorkList(SR, &C); 2784 else 2785 Postponed.push_back(SR); 2786 2787 return; 2788 } 2789 2790 if (isa<NonStaticGlobalSpaceRegion>(baseR)) { 2791 AddToWorkList(baseR, &C); 2792 return; 2793 } 2794 2795 // CXXThisRegion in the current or parent location context is live. 2796 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(baseR)) { 2797 const auto *StackReg = 2798 cast<StackArgumentsSpaceRegion>(TR->getSuperRegion()); 2799 const StackFrameContext *RegCtx = StackReg->getStackFrame(); 2800 if (CurrentLCtx && 2801 (RegCtx == CurrentLCtx || RegCtx->isParentOf(CurrentLCtx))) 2802 AddToWorkList(TR, &C); 2803 } 2804} 2805 2806void RemoveDeadBindingsWorker::VisitCluster(const MemRegion *baseR, 2807 const ClusterBindings *C) { 2808 if (!C) 2809 return; 2810 2811 // Mark the symbol for any SymbolicRegion with live bindings as live itself. 2812 // This means we should continue to track that symbol. 2813 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(baseR)) 2814 SymReaper.markLive(SymR->getSymbol()); 2815 2816 for (const auto &[Key, Val] : *C) { 2817 // Element index of a binding key is live. 2818 SymReaper.markElementIndicesLive(Key.getRegion()); 2819 2820 VisitBinding(Val); 2821 } 2822} 2823 2824void RemoveDeadBindingsWorker::VisitBinding(SVal V) { 2825 // Is it a LazyCompoundVal? All referenced regions are live as well. 2826 // The LazyCompoundVal itself is not live but should be readable. 2827 if (auto LCS = V.getAs<nonloc::LazyCompoundVal>()) { 2828 SymReaper.markLazilyCopied(LCS->getRegion()); 2829 2830 for (SVal V : RM.getInterestingValues(*LCS)) { 2831 if (auto DepLCS = V.getAs<nonloc::LazyCompoundVal>()) 2832 SymReaper.markLazilyCopied(DepLCS->getRegion()); 2833 else 2834 VisitBinding(V); 2835 } 2836 2837 return; 2838 } 2839 2840 // If V is a region, then add it to the worklist. 2841 if (const MemRegion *R = V.getAsRegion()) { 2842 AddToWorkList(R); 2843 SymReaper.markLive(R); 2844 2845 // All regions captured by a block are also live. 2846 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(R)) { 2847 for (auto Var : BR->referenced_vars()) 2848 AddToWorkList(Var.getCapturedRegion()); 2849 } 2850 } 2851 2852 2853 // Update the set of live symbols. 2854 for (SymbolRef Sym : V.symbols()) 2855 SymReaper.markLive(Sym); 2856} 2857 2858bool RemoveDeadBindingsWorker::UpdatePostponed() { 2859 // See if any postponed SymbolicRegions are actually live now, after 2860 // having done a scan. 2861 bool Changed = false; 2862 2863 for (const SymbolicRegion *SR : Postponed) { 2864 if (SymReaper.isLive(SR->getSymbol())) { 2865 Changed |= AddToWorkList(SR); 2866 SR = nullptr; 2867 } 2868 } 2869 2870 return Changed; 2871} 2872 2873StoreRef RegionStoreManager::removeDeadBindings(Store store, 2874 const StackFrameContext *LCtx, 2875 SymbolReaper& SymReaper) { 2876 RegionBindingsRef B = getRegionBindings(store); 2877 RemoveDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx); 2878 W.GenerateClusters(); 2879 2880 // Enqueue the region roots onto the worklist. 2881 for (const MemRegion *Reg : SymReaper.regions()) { 2882 W.AddToWorkList(Reg); 2883 } 2884 2885 do W.RunWorkList(); while (W.UpdatePostponed()); 2886 2887 // We have now scanned the store, marking reachable regions and symbols 2888 // as live. We now remove all the regions that are dead from the store 2889 // as well as update DSymbols with the set symbols that are now dead. 2890 for (const MemRegion *Base : llvm::make_first_range(B)) { 2891 // If the cluster has been visited, we know the region has been marked. 2892 // Otherwise, remove the dead entry. 2893 if (!W.isVisited(Base)) 2894 B = B.remove(Base); 2895 } 2896 2897 return StoreRef(B.asStore(), *this); 2898} 2899 2900//===----------------------------------------------------------------------===// 2901// Utility methods. 2902//===----------------------------------------------------------------------===// 2903 2904void RegionStoreManager::printJson(raw_ostream &Out, Store S, const char *NL, 2905 unsigned int Space, bool IsDot) const { 2906 RegionBindingsRef Bindings = getRegionBindings(S); 2907 2908 Indent(Out, Space, IsDot) << "\"store\": "; 2909 2910 if (Bindings.isEmpty()) { 2911 Out << "null," << NL; 2912 return; 2913 } 2914 2915 Out << "{ \"pointer\": \"" << Bindings.asStore() << "\", \"items\": [" << NL; 2916 Bindings.printJson(Out, NL, Space + 1, IsDot); 2917 Indent(Out, Space, IsDot) << "]}," << NL; 2918} 2919