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(Ptr: P.getOpaqueValue());
94 ID.AddInteger(I: 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>(Val: R), cast<SubRegion>(Val: 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, k: BindingKey::Direct).
213 removeBinding(R, k: 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(x: CI) != CE)
249 Out << ',';
250 Out << NL;
251 }
252
253 --Space;
254 Indent(Out, Space, IsDot) << "]}";
255 if (std::next(x: I) != E)
256 Out << ',';
257 Out << NL;
258 }
259 }
260
261 LLVM_DUMP_METHOD void dump() const { printJson(Out&: 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, k: 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, k: 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(K: Base);
283 ClusterBindings Cluster =
284 (ExistingCluster ? *ExistingCluster : CBFactory->getEmptyMap());
285
286 ClusterBindings NewCluster = CBFactory->add(Old: Cluster, K, D: V);
287 return add(K: Base, D: NewCluster);
288}
289
290
291RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R,
292 BindingKey::Kind k,
293 SVal V) const {
294 return addBinding(K: BindingKey::Make(R, k), V);
295}
296
297const SVal *RegionBindingsRef::lookup(BindingKey K) const {
298 const ClusterBindings *Cluster = lookup(K: 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(K: BindingKey::Make(R, k));
307}
308
309RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) {
310 const MemRegion *Base = K.getBaseRegion();
311 const ClusterBindings *Cluster = lookup(K: Base);
312 if (!Cluster)
313 return *this;
314
315 ClusterBindings NewCluster = CBFactory->remove(Old: *Cluster, K);
316 if (NewCluster.isEmpty())
317 return remove(K: Base);
318 return add(K: Base, D: NewCluster);
319}
320
321RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R,
322 BindingKey::Kind k){
323 return removeBinding(K: 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>(Val: 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(B: 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(K: BindingKey::Make(R, k: 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>(Val: R))
474 if (BR->getDecl()->isEmpty())
475 return StoreRef(store, *this);
476
477 RegionBindingsRef B = getRegionBindings(store);
478 SVal V = svalBuilder.makeZeroVal(type: Ctx.CharTy);
479 B = removeSubRegionBindings(B, R: cast<SubRegion>(Val: R));
480 B = B.addBinding(K: BindingKey::Make(R, k: 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(B: getRegionBindings(store: S), L, T);
553 }
554
555 std::optional<SVal> getDefaultBinding(Store S, const MemRegion *R) override {
556 RegionBindingsRef B = getRegionBindings(store: 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: 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>(Val: Key.getRegion())) {
654 // FIXME: Possibly incorporate the offset?
655 if (!f.HandleBinding(SMgr&: *this, store, region: R, val: 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>(args&: 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(K: 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(Ptr: 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(Ptr: C).second)
751 return false;
752 WL.push_back(Elt: 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(R: 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(store: S);
787 const ClusterBindings *Cluster = B.lookup(K: 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(val: 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>(Val: R))
815 if (!isUnionField(FR))
816 Fields.push_back(Elt: FR->getDecl());
817
818 R = cast<SubRegion>(Val: 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, Fields&: 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(K: TopKey, Fields&: FieldsInSymbolicSubregions);
858 Top = TopKey.getConcreteOffsetRegion();
859 TopKey = BindingKey::Make(R: Top, k: 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(MR: 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>(Val: Top)) {
872 if (FR->getDecl()->isBitField())
873 Length = FR->getDecl()->getBitWidthValue(Ctx: 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(Elt: 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(Elt: StoreEntry);
899 }
900
901 } else if (NextKey.hasSymbolicOffset()) {
902 const MemRegion *Base = NextKey.getConcreteOffsetRegion();
903 if (Top->isSubRegionOf(R: 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(K: NextKey, Fields: FieldsInSymbolicSubregions))
909 Bindings.push_back(Elt: StoreEntry);
910 } else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Val: 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(R: Top))
914 if (isCompatibleWithFields(K: NextKey, Fields: FieldsInSymbolicSubregions))
915 Bindings.push_back(Elt: 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 TopKey: BindingKey::Make(R: Top, k: BindingKey::Default),
927 IncludeAllDefaultBindings);
928}
929
930RegionBindingsRef
931RegionStoreManager::removeSubRegionBindings(RegionBindingsConstRef B,
932 const SubRegion *Top) {
933 BindingKey TopKey = BindingKey::Make(R: Top, k: 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(K: Top);
939 }
940
941 const ClusterBindings *Cluster = B.lookup(K: 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(R: Concrete, k: BindingKey::Default, V: UnknownVal());
948 }
949 return B;
950 }
951
952 SmallVector<BindingPair, 32> Bindings;
953 collectSubRegionBindings(Bindings, SVB&: svalBuilder, Cluster: *Cluster, Top, TopKey,
954 /*IncludeAllDefaultBindings=*/false);
955
956 ClusterBindingsRef Result(*Cluster, CBFactory);
957 for (BindingKey Key : llvm::make_first_range(c&: Bindings))
958 Result = Result.remove(K: 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(K: BindingKey::Make(R: Concrete, k: BindingKey::Default),
967 D: UnknownVal());
968 }
969
970 if (Result.isEmpty())
971 return B.remove(K: ClusterHead);
972 return B.add(K: ClusterHead, D: 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 MR: R, IK: RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
1019 const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion();
1020 return AddToWorkList(E: WorkListElement(BaseR), C: getCluster(R: 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(V: 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(LCV: *LCS))
1040 if (!isa<nonloc::LazyCompoundVal>(Val: 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(MR: baseR,
1052 IK: RegionAndSymbolInvalidationTraits::TK_PreserveContents);
1053
1054 if (C) {
1055 for (SVal Val : llvm::make_second_range(c: *C))
1056 VisitBinding(V: Val);
1057
1058 // Invalidate regions contents.
1059 if (!PreserveRegionsContents)
1060 B = B.remove(K: baseR);
1061 }
1062
1063 if (const auto *TO = dyn_cast<TypedValueRegion>(Val: 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(InnerMatcher: varDecl(hasStaticStorageDuration()).bind(ID: DeclBind)))));
1075 auto Matches =
1076 match(Matcher: RefToStatic, Node: *RD->getLambdaCallOperator()->getBody(),
1077 Context&: RD->getASTContext());
1078
1079 for (BoundNodes &Match : Matches) {
1080 auto *VD = Match.getNodeAs<VarDecl>(ID: DeclBind);
1081 const VarRegion *ToInvalidate =
1082 RM.getRegionManager().getVarRegion(VD, LC: LCtx);
1083 AddToWorkList(R: 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>(Val: 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(R: VR);
1097 }
1098 else if (Loc::isLocType(T: 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, L: loc::MemRegionVal(VR));
1105 if (std::optional<Loc> L = V.getAs<Loc>()) {
1106 if (const MemRegion *LR = L->getAsRegion())
1107 AddToWorkList(R: LR);
1108 }
1109 }
1110 }
1111 return;
1112 }
1113
1114 // Symbolic region?
1115 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Val: baseR))
1116 IS.insert(V: 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(Elt: baseR);
1125
1126 if (isa<AllocaRegion, SymbolicRegion>(Val: 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(symbolTag: baseR, expr: Ex, LCtx, type: Ctx.IntTy, count: Count);
1131 B = B.addBinding(R: baseR, k: BindingKey::Default, V);
1132 return;
1133 }
1134
1135 if (!baseR->isBoundable())
1136 return;
1137
1138 const TypedValueRegion *TR = cast<TypedValueRegion>(Val: baseR);
1139 QualType T = TR->getValueType();
1140
1141 if (isInitiallyIncludedGlobalRegion(R: 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(symbolTag: baseR, expr: Ex, LCtx,
1152 type: Ctx.IntTy, count: Count);
1153 B = B.addBinding(R: baseR, k: BindingKey::Default, V);
1154 return;
1155 }
1156
1157 if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
1158 bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1159 MR: baseR,
1160 IK: 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>(Val: AT))
1169 NumElements = CAT->getZExtSize();
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(T: 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(R: 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(K: 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(K: 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>(Val: 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(symbolTag: baseR, expr: Ex, LCtx,
1221 type: AT->getElementType(), count: Count);
1222 B = B.addBinding(R: baseR, k: BindingKey::Default, V);
1223 return;
1224 }
1225
1226 DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(symbolTag: baseR, expr: Ex, LCtx,
1227 type: T,count: Count);
1228 assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
1229 B = B.addBinding(R: baseR, k: 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>(Val: R->getMemorySpace());
1239 case GFK_All:
1240 return isa<NonStaticGlobalSpaceRegion>(Val: R->getMemorySpace());
1241 }
1242
1243 llvm_unreachable("unknown globals filter");
1244}
1245
1246bool InvalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) {
1247 if (isInitiallyIncludedGlobalRegion(R: Base))
1248 return true;
1249
1250 const MemSpaceRegion *MemSpace = Base->getMemorySpace();
1251 return ITraits.hasTrait(MR: MemSpace,
1252 IK: 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, expr: Ex, LCtx,
1266 /* type does not matter */ type: Ctx.IntTy,
1267 count: Count);
1268
1269 B = B.removeBinding(R: GS)
1270 .addBinding(K: BindingKey::Make(R: GS, k: 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(Elt: 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(LCV: *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(Elt: 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(K: MemRegion::GlobalInternalSpaceRegionKind,
1343 Ex, Count, LCtx, B, Invalidated);
1344 [[fallthrough]];
1345 case GFK_SystemOnly:
1346 B = invalidateGlobalRegion(K: 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>(Val: Array))
1368 return Array;
1369
1370 if (!isa<loc::MemRegionVal>(Val: Array))
1371 return UnknownVal();
1372
1373 const SubRegion *R =
1374 cast<SubRegion>(Val: Array.castAs<loc::MemRegionVal>().getRegion());
1375 NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
1376 return loc::MemRegionVal(MRMgr.getElementRegion(elementType: T, Idx: ZeroIdx, superRegion: 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>(Val: MR)) {
1403 return UnknownVal();
1404 }
1405
1406 // Auto-detect the binding type.
1407 if (T.isNull()) {
1408 if (const auto *TVR = dyn_cast<TypedValueRegion>(Val: MR))
1409 T = TVR->getValueType();
1410 else if (const auto *TR = dyn_cast<TypedRegion>(Val: MR))
1411 T = TR->getLocationType()->getPointeeType();
1412 else if (const auto *SR = dyn_cast<SymbolicRegion>(Val: 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>(Val: MR))
1419 MR = GetElementZeroRegion(R: cast<SubRegion>(Val: 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>(Val: 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>(Val: R))
1458 return svalBuilder.evalCast(V: getBindingForField(B, R: FR), CastTy: T, OriginalTy: QualType{});
1459
1460 if (const ElementRegion* ER = dyn_cast<ElementRegion>(Val: 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(V: getBindingForElement(B, R: ER), CastTy: T, OriginalTy: QualType{});
1467 }
1468
1469 if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(Val: 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(V: getBindingForObjCIvar(B, R: IVR), CastTy: T, OriginalTy: QualType{});
1477 }
1478
1479 if (const VarRegion *VR = dyn_cast<VarRegion>(Val: 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(V: getBindingForVar(B, R: VR), CastTy: T, OriginalTy: QualType{});
1487 }
1488
1489 const SVal *V = B.lookup(R, k: 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(region: R);
1508}
1509
1510static QualType getUnderlyingType(const SubRegion *R) {
1511 QualType RegionTy;
1512 if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(Val: R))
1513 RegionTy = TVR->getValueType();
1514
1515 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Val: 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(T1: RegionTy, T2: 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, Cluster: *B.lookup(K: R->getBaseRegion()), Top: 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(SVB&: svalBuilder, B, R, AllowSubregionBindings: true))
1570 return std::make_pair(x: V->getStore(), y: 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>(Val: R)) {
1577 Result = findLazyBinding(B, R: cast<SubRegion>(Val: ER->getSuperRegion()),
1578 originalRegion);
1579
1580 if (Result.second)
1581 Result.second = MRMgr.getElementRegionWithSuper(ER, superRegion: Result.second);
1582
1583 } else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Val: R)) {
1584 Result = findLazyBinding(B, R: cast<SubRegion>(Val: FR->getSuperRegion()),
1585 originalRegion);
1586
1587 if (Result.second)
1588 Result.second = MRMgr.getFieldRegionWithSuper(FR, superRegion: Result.second);
1589
1590 } else if (const CXXBaseObjectRegion *BaseReg =
1591 dyn_cast<CXXBaseObjectRegion>(Val: 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, R: cast<SubRegion>(Val: BaseReg->getSuperRegion()),
1595 originalRegion);
1596
1597 if (Result.second)
1598 Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(baseReg: BaseReg,
1599 superRegion: 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>(Val: CAT->getCanonicalTypeInternal());
1614 SmallVector<uint64_t, 2> Extents;
1615 do {
1616 Extents.push_back(Elt: CAT->getZExtSize());
1617 } while ((CAT = dyn_cast<ConstantArrayType>(Val: 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(Elt: ER->getIndex());
1642 Base = ER->getSuperRegion();
1643 ER = dyn_cast<ElementRegion>(Val: 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(N: 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(C: 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(RHS: *(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(args&: SValOffsets, args&: Base) = getElementRegionOffsetsWithBase(ER: R);
1720 const VarRegion *VR = dyn_cast<VarRegion>(Val: 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(D&: 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(T: 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 SrcOffsets: SValOffsets, ArrayExtents: Extents, DstOffsets&: 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>(Val: Init))
1777 return getSValFromInitListExpr(ILE, ConcreteOffsets, ElemT: R->getElementType());
1778
1779 // Handle StringLiteral.
1780 // Example:
1781 // const char arr[] = "abc";
1782 if (const auto *SL = dyn_cast<StringLiteral>(Val: Init))
1783 return getSValFromStringLiteral(SL, Offset: ConcreteOffsets.front(),
1784 ElemT: 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>(Val: ILE->getInit(Init: 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(type: ElemT);
1828
1829 const Expr *E = ILE->getInit(Init: Offset);
1830 const auto *IL = dyn_cast<InitListExpr>(Val: 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(i: Offset);
1880 return svalBuilder.makeIntVal(integer: Code, type: 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(T: BaseTy) >= Ctx.getTypeSizeInChars(T: Ty)) {
1891 if (const std::optional<SVal> &ParentValue =
1892 B.getDirectBinding(R: BaseRegion)) {
1893 if (SymbolRef ParentValueAsSym = ParentValue->getAsSymbol())
1894 return SVB.getDerivedRegionValueSymbolVal(parentSymbol: ParentValueAsSym, region: 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>(Val: 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(T: StrR->getValueType())->getElementType();
1922 if (!Ctx.hasSameUnqualifiedType(T1: T, T2: 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, Offset: Idx.getZExtValue(), ElemT: T);
1930 }
1931 } else if (isa<ElementRegion, VarRegion>(Val: 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>(Val: 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>(Val: O.getRegion()))
1953 if (auto V = getDerivedSymbolForBinding(B, BaseRegion: baseR, SubReg: R, Ctx, SVB&: svalBuilder))
1954 return *V;
1955
1956 return getBindingForFieldOrElementCommon(B, R, Ty: 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>(Val: 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>(Val: Init)) {
1981 if (Index < InitList->getNumInits()) {
1982 if (const Expr *FieldInit = InitList->getInit(Init: Index))
1983 if (std::optional<SVal> V = svalBuilder.getConstantVal(E: FieldInit))
1984 return *V;
1985 } else {
1986 return svalBuilder.makeZeroVal(type: 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 *)&copy;
2005 // return bits->b; <-- here
2006 // }
2007 if (const auto *Base = dyn_cast<TypedValueRegion>(Val: R->getBaseRegion()))
2008 if (auto V = getDerivedSymbolForBinding(B, BaseRegion: Base, SubReg: R, Ctx, SVB&: 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(R: superR)) {
2019 SVal val = *D;
2020 if (SymbolRef parentSym = val.getAsSymbol())
2021 return svalBuilder.getDerivedRegionValueSymbolVal(parentSymbol: parentSym, region: R);
2022
2023 if (val.isZeroConstant())
2024 return svalBuilder.makeZeroVal(type: 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: 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>(Val: LazyBindingRegion))
2044 Result = getBindingForElement(B: LazyBinding, R: ER);
2045 else
2046 Result = getBindingForField(B: LazyBinding,
2047 R: cast<FieldRegion>(Val: 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(args&: lazyBindingStore, args&: lazyBindingRegion) = findLazyBinding(B, R, originalRegion: R);
2081 if (lazyBindingRegion)
2082 return getLazyBinding(LazyBindingRegion: lazyBindingRegion,
2083 LazyBinding: getRegionBindings(store: 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, superR: 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>(Val: 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>(Val: Base);
2127 }
2128
2129 if (R->hasStackNonParametersStorage()) {
2130 if (isa<ElementRegion>(Val: 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>(Val: 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>(Val: 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(region: 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(R: superR)) {
2171 if (SymbolRef parentSym = V->getAsSymbol())
2172 return svalBuilder.getDerivedRegionValueSymbolVal(parentSymbol: parentSym, region: 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>(Val: MS))
2197 return svalBuilder.getRegionValueSymbolVal(region: 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(E: 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>(Val: MS))
2215 return svalBuilder.getRegionValueSymbolVal(region: R);
2216
2217 if (isa<GlobalsSpaceRegion>(Val: 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(E: 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>(Val: MS))
2231 return svalBuilder.makeZeroVal(type: T);
2232
2233 if (std::optional<SVal> V = getBindingForDerivedDefaultValue(B, superR: MS, R, Ty: T)) {
2234 assert(!V->getAs<nonloc::LazyCompoundVal>());
2235 return *V;
2236 }
2237
2238 return svalBuilder.getRegionValueSymbolVal(region: R);
2239 }
2240
2241 return UndefinedVal();
2242}
2243
2244SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
2245 // All other values are symbolic.
2246 return svalBuilder.getRegionValueSymbolVal(region: R);
2247}
2248
2249const RegionStoreManager::SValListTy &
2250RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) {
2251 // First, check the cache.
2252 LazyBindingsMapTy::iterator I = LazyBindingsMap.find(Val: 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(store: 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(K: LazyR->getBaseRegion());
2265 if (!Cluster)
2266 return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2267
2268 SmallVector<BindingPair, 32> Bindings;
2269 collectSubRegionBindings(Bindings, SVB&: svalBuilder, Cluster: *Cluster, Top: LazyR,
2270 /*IncludeAllDefaultBindings=*/true);
2271 for (SVal V : llvm::make_second_range(c&: Bindings)) {
2272 if (V.isUnknownOrUndef() || V.isConstant())
2273 continue;
2274
2275 if (auto InnerLCV = V.getAs<nonloc::LazyCompoundVal>()) {
2276 const SValListTy &InnerList = getInterestingValues(LCV: *InnerLCV);
2277 List.insert(position: List.end(), first: InnerList.begin(), last: InnerList.end());
2278 }
2279
2280 List.push_back(x: 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(SVB&: svalBuilder, B, R, AllowSubregionBindings: false))
2290 return *V;
2291
2292 return svalBuilder.makeLazyCompoundVal(store: StoreRef(B.asStore(), *this), region: 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>(Val: 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(K: 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(store: 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 // We only care about region locations.
2362 auto MemRegVal = L.getAs<loc::MemRegionVal>();
2363 if (!MemRegVal)
2364 return B;
2365
2366 const MemRegion *R = MemRegVal->getRegion();
2367
2368 // Check if the region is a struct region.
2369 if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(Val: R)) {
2370 QualType Ty = TR->getValueType();
2371 if (Ty->isArrayType())
2372 return bindArray(B, R: TR, V);
2373 if (Ty->isStructureOrClassType())
2374 return bindStruct(B, R: TR, V);
2375 if (Ty->isVectorType())
2376 return bindVector(B, R: TR, V);
2377 if (Ty->isUnionType())
2378 return bindAggregate(B, R: TR, DefaultVal: V);
2379 }
2380
2381 // Binding directly to a symbolic region should be treated as binding
2382 // to element 0.
2383 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Val: R))
2384 R = GetElementZeroRegion(R: SR, T: SR->getPointeeStaticType());
2385
2386 assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) &&
2387 "'this' pointer is not an l-value and is not assignable");
2388
2389 // Clear out bindings that may overlap with this binding.
2390 RegionBindingsRef NewB = removeSubRegionBindings(B, Top: cast<SubRegion>(Val: R));
2391
2392 // LazyCompoundVals should be always bound as 'default' bindings.
2393 auto KeyKind = isa<nonloc::LazyCompoundVal>(Val: V) ? BindingKey::Default
2394 : BindingKey::Direct;
2395 return NewB.addBinding(K: BindingKey::Make(R, k: KeyKind), V);
2396}
2397
2398RegionBindingsRef
2399RegionStoreManager::setImplicitDefaultValue(RegionBindingsConstRef B,
2400 const MemRegion *R,
2401 QualType T) {
2402 SVal V;
2403
2404 if (Loc::isLocType(T))
2405 V = svalBuilder.makeNullWithType(type: T);
2406 else if (T->isIntegralOrEnumerationType())
2407 V = svalBuilder.makeZeroVal(type: T);
2408 else if (T->isStructureOrClassType() || T->isArrayType()) {
2409 // Set the default value to a zero constant when it is a structure
2410 // or array. The type doesn't really matter.
2411 V = svalBuilder.makeZeroVal(type: Ctx.IntTy);
2412 }
2413 else {
2414 // We can't represent values of this type, but we still need to set a value
2415 // to record that the region has been initialized.
2416 // If this assertion ever fires, a new case should be added above -- we
2417 // should know how to default-initialize any value we can symbolicate.
2418 assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
2419 V = UnknownVal();
2420 }
2421
2422 return B.addBinding(R, k: BindingKey::Default, V);
2423}
2424
2425std::optional<RegionBindingsRef> RegionStoreManager::tryBindSmallArray(
2426 RegionBindingsConstRef B, const TypedValueRegion *R, const ArrayType *AT,
2427 nonloc::LazyCompoundVal LCV) {
2428
2429 auto CAT = dyn_cast<ConstantArrayType>(Val: AT);
2430
2431 // If we don't know the size, create a lazyCompoundVal instead.
2432 if (!CAT)
2433 return std::nullopt;
2434
2435 QualType Ty = CAT->getElementType();
2436 if (!(Ty->isScalarType() || Ty->isReferenceType()))
2437 return std::nullopt;
2438
2439 // If the array is too big, create a LCV instead.
2440 uint64_t ArrSize = CAT->getLimitedSize();
2441 if (ArrSize > SmallArrayLimit)
2442 return std::nullopt;
2443
2444 RegionBindingsRef NewB = B;
2445
2446 for (uint64_t i = 0; i < ArrSize; ++i) {
2447 auto Idx = svalBuilder.makeArrayIndex(idx: i);
2448 const ElementRegion *SrcER =
2449 MRMgr.getElementRegion(elementType: Ty, Idx, superRegion: LCV.getRegion(), Ctx);
2450 SVal V = getBindingForElement(B: getRegionBindings(store: LCV.getStore()), R: SrcER);
2451
2452 const ElementRegion *DstER = MRMgr.getElementRegion(elementType: Ty, Idx, superRegion: R, Ctx);
2453 NewB = bind(B: NewB, L: loc::MemRegionVal(DstER), V);
2454 }
2455
2456 return NewB;
2457}
2458
2459RegionBindingsRef
2460RegionStoreManager::bindArray(RegionBindingsConstRef B,
2461 const TypedValueRegion* R,
2462 SVal Init) {
2463
2464 const ArrayType *AT =cast<ArrayType>(Val: Ctx.getCanonicalType(T: R->getValueType()));
2465 QualType ElementTy = AT->getElementType();
2466 std::optional<uint64_t> Size;
2467
2468 if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(Val: AT))
2469 Size = CAT->getZExtSize();
2470
2471 // Check if the init expr is a literal. If so, bind the rvalue instead.
2472 // FIXME: It's not responsibility of the Store to transform this lvalue
2473 // to rvalue. ExprEngine or maybe even CFG should do this before binding.
2474 if (std::optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) {
2475 SVal V = getBinding(S: B.asStore(), L: *MRV, T: R->getValueType());
2476 return bindAggregate(B, R, DefaultVal: V);
2477 }
2478
2479 // Handle lazy compound values.
2480 if (std::optional<nonloc::LazyCompoundVal> LCV =
2481 Init.getAs<nonloc::LazyCompoundVal>()) {
2482 if (std::optional<RegionBindingsRef> NewB =
2483 tryBindSmallArray(B, R, AT, LCV: *LCV))
2484 return *NewB;
2485
2486 return bindAggregate(B, R, DefaultVal: Init);
2487 }
2488
2489 if (Init.isUnknown())
2490 return bindAggregate(B, R, DefaultVal: UnknownVal());
2491
2492 // Remaining case: explicit compound values.
2493 const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>();
2494 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2495 uint64_t i = 0;
2496
2497 RegionBindingsRef NewB(B);
2498
2499 for (; Size ? i < *Size : true; ++i, ++VI) {
2500 // The init list might be shorter than the array length.
2501 if (VI == VE)
2502 break;
2503
2504 NonLoc Idx = svalBuilder.makeArrayIndex(idx: i);
2505 const ElementRegion *ER = MRMgr.getElementRegion(elementType: ElementTy, Idx, superRegion: R, Ctx);
2506
2507 if (ElementTy->isStructureOrClassType())
2508 NewB = bindStruct(B: NewB, R: ER, V: *VI);
2509 else if (ElementTy->isArrayType())
2510 NewB = bindArray(B: NewB, R: ER, Init: *VI);
2511 else
2512 NewB = bind(B: NewB, L: loc::MemRegionVal(ER), V: *VI);
2513 }
2514
2515 // If the init list is shorter than the array length (or the array has
2516 // variable length), set the array default value. Values that are already set
2517 // are not overwritten.
2518 if (!Size || i < *Size)
2519 NewB = setImplicitDefaultValue(B: NewB, R, T: ElementTy);
2520
2521 return NewB;
2522}
2523
2524RegionBindingsRef RegionStoreManager::bindVector(RegionBindingsConstRef B,
2525 const TypedValueRegion* R,
2526 SVal V) {
2527 QualType T = R->getValueType();
2528 const VectorType *VT = T->castAs<VectorType>(); // Use castAs for typedefs.
2529
2530 // Handle lazy compound values and symbolic values.
2531 if (isa<nonloc::LazyCompoundVal, nonloc::SymbolVal>(Val: V))
2532 return bindAggregate(B, R, DefaultVal: V);
2533
2534 // We may get non-CompoundVal accidentally due to imprecise cast logic or
2535 // that we are binding symbolic struct value. Kill the field values, and if
2536 // the value is symbolic go and bind it as a "default" binding.
2537 if (!isa<nonloc::CompoundVal>(Val: V)) {
2538 return bindAggregate(B, R, DefaultVal: UnknownVal());
2539 }
2540
2541 QualType ElemType = VT->getElementType();
2542 nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>();
2543 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2544 unsigned index = 0, numElements = VT->getNumElements();
2545 RegionBindingsRef NewB(B);
2546
2547 for ( ; index != numElements ; ++index) {
2548 if (VI == VE)
2549 break;
2550
2551 NonLoc Idx = svalBuilder.makeArrayIndex(idx: index);
2552 const ElementRegion *ER = MRMgr.getElementRegion(elementType: ElemType, Idx, superRegion: R, Ctx);
2553
2554 if (ElemType->isArrayType())
2555 NewB = bindArray(B: NewB, R: ER, Init: *VI);
2556 else if (ElemType->isStructureOrClassType())
2557 NewB = bindStruct(B: NewB, R: ER, V: *VI);
2558 else
2559 NewB = bind(B: NewB, L: loc::MemRegionVal(ER), V: *VI);
2560 }
2561 return NewB;
2562}
2563
2564std::optional<RegionBindingsRef> RegionStoreManager::tryBindSmallStruct(
2565 RegionBindingsConstRef B, const TypedValueRegion *R, const RecordDecl *RD,
2566 nonloc::LazyCompoundVal LCV) {
2567 FieldVector Fields;
2568
2569 if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(Val: RD))
2570 if (Class->getNumBases() != 0 || Class->getNumVBases() != 0)
2571 return std::nullopt;
2572
2573 for (const auto *FD : RD->fields()) {
2574 if (FD->isUnnamedBitField())
2575 continue;
2576
2577 // If there are too many fields, or if any of the fields are aggregates,
2578 // just use the LCV as a default binding.
2579 if (Fields.size() == SmallStructLimit)
2580 return std::nullopt;
2581
2582 QualType Ty = FD->getType();
2583
2584 // Zero length arrays are basically no-ops, so we also ignore them here.
2585 if (Ty->isConstantArrayType() &&
2586 Ctx.getConstantArrayElementCount(CA: Ctx.getAsConstantArrayType(T: Ty)) == 0)
2587 continue;
2588
2589 if (!(Ty->isScalarType() || Ty->isReferenceType()))
2590 return std::nullopt;
2591
2592 Fields.push_back(Elt: FD);
2593 }
2594
2595 RegionBindingsRef NewB = B;
2596
2597 for (const FieldDecl *Field : Fields) {
2598 const FieldRegion *SourceFR = MRMgr.getFieldRegion(fd: Field, superRegion: LCV.getRegion());
2599 SVal V = getBindingForField(B: getRegionBindings(store: LCV.getStore()), R: SourceFR);
2600
2601 const FieldRegion *DestFR = MRMgr.getFieldRegion(fd: Field, superRegion: R);
2602 NewB = bind(B: NewB, L: loc::MemRegionVal(DestFR), V);
2603 }
2604
2605 return NewB;
2606}
2607
2608RegionBindingsRef RegionStoreManager::bindStruct(RegionBindingsConstRef B,
2609 const TypedValueRegion *R,
2610 SVal V) {
2611 QualType T = R->getValueType();
2612 assert(T->isStructureOrClassType());
2613
2614 const RecordType* RT = T->castAs<RecordType>();
2615 const RecordDecl *RD = RT->getDecl();
2616
2617 if (!RD->isCompleteDefinition())
2618 return B;
2619
2620 // Handle lazy compound values and symbolic values.
2621 if (std::optional<nonloc::LazyCompoundVal> LCV =
2622 V.getAs<nonloc::LazyCompoundVal>()) {
2623 if (std::optional<RegionBindingsRef> NewB =
2624 tryBindSmallStruct(B, R, RD, LCV: *LCV))
2625 return *NewB;
2626 return bindAggregate(B, R, DefaultVal: V);
2627 }
2628 if (isa<nonloc::SymbolVal>(Val: V))
2629 return bindAggregate(B, R, DefaultVal: V);
2630
2631 // We may get non-CompoundVal accidentally due to imprecise cast logic or
2632 // that we are binding symbolic struct value. Kill the field values, and if
2633 // the value is symbolic go and bind it as a "default" binding.
2634 if (V.isUnknown() || !isa<nonloc::CompoundVal>(Val: V))
2635 return bindAggregate(B, R, DefaultVal: UnknownVal());
2636
2637 // The raw CompoundVal is essentially a symbolic InitListExpr: an (immutable)
2638 // list of other values. It appears pretty much only when there's an actual
2639 // initializer list expression in the program, and the analyzer tries to
2640 // unwrap it as soon as possible.
2641 // This code is where such unwrap happens: when the compound value is put into
2642 // the object that it was supposed to initialize (it's an *initializer* list,
2643 // after all), instead of binding the whole value to the whole object, we bind
2644 // sub-values to sub-objects. Sub-values may themselves be compound values,
2645 // and in this case the procedure becomes recursive.
2646 // FIXME: The annoying part about compound values is that they don't carry
2647 // any sort of information about which value corresponds to which sub-object.
2648 // It's simply a list of values in the middle of nowhere; we expect to match
2649 // them to sub-objects, essentially, "by index": first value binds to
2650 // the first field, second value binds to the second field, etc.
2651 // It would have been much safer to organize non-lazy compound values as
2652 // a mapping from fields/bases to values.
2653 const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>();
2654 nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2655
2656 RegionBindingsRef NewB(B);
2657
2658 // In C++17 aggregates may have base classes, handle those as well.
2659 // They appear before fields in the initializer list / compound value.
2660 if (const auto *CRD = dyn_cast<CXXRecordDecl>(Val: RD)) {
2661 // If the object was constructed with a constructor, its value is a
2662 // LazyCompoundVal. If it's a raw CompoundVal, it means that we're
2663 // performing aggregate initialization. The only exception from this
2664 // rule is sending an Objective-C++ message that returns a C++ object
2665 // to a nil receiver; in this case the semantics is to return a
2666 // zero-initialized object even if it's a C++ object that doesn't have
2667 // this sort of constructor; the CompoundVal is empty in this case.
2668 assert((CRD->isAggregate() || (Ctx.getLangOpts().ObjC && VI == VE)) &&
2669 "Non-aggregates are constructed with a constructor!");
2670
2671 for (const auto &B : CRD->bases()) {
2672 // (Multiple inheritance is fine though.)
2673 assert(!B.isVirtual() && "Aggregates cannot have virtual base classes!");
2674
2675 if (VI == VE)
2676 break;
2677
2678 QualType BTy = B.getType();
2679 assert(BTy->isStructureOrClassType() && "Base classes must be classes!");
2680
2681 const CXXRecordDecl *BRD = BTy->getAsCXXRecordDecl();
2682 assert(BRD && "Base classes must be C++ classes!");
2683
2684 const CXXBaseObjectRegion *BR =
2685 MRMgr.getCXXBaseObjectRegion(BaseClass: BRD, Super: R, /*IsVirtual=*/false);
2686
2687 NewB = bindStruct(B: NewB, R: BR, V: *VI);
2688
2689 ++VI;
2690 }
2691 }
2692
2693 RecordDecl::field_iterator FI, FE;
2694
2695 for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
2696
2697 if (VI == VE)
2698 break;
2699
2700 // Skip any unnamed bitfields to stay in sync with the initializers.
2701 if (FI->isUnnamedBitField())
2702 continue;
2703
2704 QualType FTy = FI->getType();
2705 const FieldRegion* FR = MRMgr.getFieldRegion(fd: *FI, superRegion: R);
2706
2707 if (FTy->isArrayType())
2708 NewB = bindArray(B: NewB, R: FR, Init: *VI);
2709 else if (FTy->isStructureOrClassType())
2710 NewB = bindStruct(B: NewB, R: FR, V: *VI);
2711 else
2712 NewB = bind(B: NewB, L: loc::MemRegionVal(FR), V: *VI);
2713 ++VI;
2714 }
2715
2716 // There may be fewer values in the initialize list than the fields of struct.
2717 if (FI != FE) {
2718 NewB = NewB.addBinding(R, k: BindingKey::Default,
2719 V: svalBuilder.makeIntVal(integer: 0, isUnsigned: false));
2720 }
2721
2722 return NewB;
2723}
2724
2725RegionBindingsRef
2726RegionStoreManager::bindAggregate(RegionBindingsConstRef B,
2727 const TypedRegion *R,
2728 SVal Val) {
2729 // Remove the old bindings, using 'R' as the root of all regions
2730 // we will invalidate. Then add the new binding.
2731 return removeSubRegionBindings(B, Top: R).addBinding(R, k: BindingKey::Default, V: Val);
2732}
2733
2734//===----------------------------------------------------------------------===//
2735// State pruning.
2736//===----------------------------------------------------------------------===//
2737
2738namespace {
2739class RemoveDeadBindingsWorker
2740 : public ClusterAnalysis<RemoveDeadBindingsWorker> {
2741 SmallVector<const SymbolicRegion *, 12> Postponed;
2742 SymbolReaper &SymReaper;
2743 const StackFrameContext *CurrentLCtx;
2744
2745public:
2746 RemoveDeadBindingsWorker(RegionStoreManager &rm,
2747 ProgramStateManager &stateMgr,
2748 RegionBindingsRef b, SymbolReaper &symReaper,
2749 const StackFrameContext *LCtx)
2750 : ClusterAnalysis<RemoveDeadBindingsWorker>(rm, stateMgr, b),
2751 SymReaper(symReaper), CurrentLCtx(LCtx) {}
2752
2753 // Called by ClusterAnalysis.
2754 void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C);
2755 void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
2756 using ClusterAnalysis<RemoveDeadBindingsWorker>::VisitCluster;
2757
2758 using ClusterAnalysis::AddToWorkList;
2759
2760 bool AddToWorkList(const MemRegion *R);
2761
2762 bool UpdatePostponed();
2763 void VisitBinding(SVal V);
2764};
2765}
2766
2767bool RemoveDeadBindingsWorker::AddToWorkList(const MemRegion *R) {
2768 const MemRegion *BaseR = R->getBaseRegion();
2769 return AddToWorkList(E: WorkListElement(BaseR), C: getCluster(R: BaseR));
2770}
2771
2772void RemoveDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
2773 const ClusterBindings &C) {
2774
2775 if (const VarRegion *VR = dyn_cast<VarRegion>(Val: baseR)) {
2776 if (SymReaper.isLive(VR))
2777 AddToWorkList(E: baseR, C: &C);
2778
2779 return;
2780 }
2781
2782 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Val: baseR)) {
2783 if (SymReaper.isLive(sym: SR->getSymbol()))
2784 AddToWorkList(E: SR, C: &C);
2785 else
2786 Postponed.push_back(Elt: SR);
2787
2788 return;
2789 }
2790
2791 if (isa<NonStaticGlobalSpaceRegion>(Val: baseR)) {
2792 AddToWorkList(E: baseR, C: &C);
2793 return;
2794 }
2795
2796 // CXXThisRegion in the current or parent location context is live.
2797 if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(Val: baseR)) {
2798 const auto *StackReg =
2799 cast<StackArgumentsSpaceRegion>(Val: TR->getSuperRegion());
2800 const StackFrameContext *RegCtx = StackReg->getStackFrame();
2801 if (CurrentLCtx &&
2802 (RegCtx == CurrentLCtx || RegCtx->isParentOf(LC: CurrentLCtx)))
2803 AddToWorkList(E: TR, C: &C);
2804 }
2805}
2806
2807void RemoveDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
2808 const ClusterBindings *C) {
2809 if (!C)
2810 return;
2811
2812 // Mark the symbol for any SymbolicRegion with live bindings as live itself.
2813 // This means we should continue to track that symbol.
2814 if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Val: baseR))
2815 SymReaper.markLive(sym: SymR->getSymbol());
2816
2817 for (const auto &[Key, Val] : *C) {
2818 // Element index of a binding key is live.
2819 SymReaper.markElementIndicesLive(region: Key.getRegion());
2820
2821 VisitBinding(V: Val);
2822 }
2823}
2824
2825void RemoveDeadBindingsWorker::VisitBinding(SVal V) {
2826 // Is it a LazyCompoundVal? All referenced regions are live as well.
2827 // The LazyCompoundVal itself is not live but should be readable.
2828 if (auto LCS = V.getAs<nonloc::LazyCompoundVal>()) {
2829 SymReaper.markLazilyCopied(region: LCS->getRegion());
2830
2831 for (SVal V : RM.getInterestingValues(LCV: *LCS)) {
2832 if (auto DepLCS = V.getAs<nonloc::LazyCompoundVal>())
2833 SymReaper.markLazilyCopied(region: DepLCS->getRegion());
2834 else
2835 VisitBinding(V);
2836 }
2837
2838 return;
2839 }
2840
2841 // If V is a region, then add it to the worklist.
2842 if (const MemRegion *R = V.getAsRegion()) {
2843 AddToWorkList(R);
2844 SymReaper.markLive(region: R);
2845
2846 // All regions captured by a block are also live.
2847 if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(Val: R)) {
2848 for (auto Var : BR->referenced_vars())
2849 AddToWorkList(R: Var.getCapturedRegion());
2850 }
2851 }
2852
2853
2854 // Update the set of live symbols.
2855 for (SymbolRef Sym : V.symbols())
2856 SymReaper.markLive(sym: Sym);
2857}
2858
2859bool RemoveDeadBindingsWorker::UpdatePostponed() {
2860 // See if any postponed SymbolicRegions are actually live now, after
2861 // having done a scan.
2862 bool Changed = false;
2863
2864 for (const SymbolicRegion *SR : Postponed) {
2865 if (SymReaper.isLive(sym: SR->getSymbol())) {
2866 Changed |= AddToWorkList(R: SR);
2867 SR = nullptr;
2868 }
2869 }
2870
2871 return Changed;
2872}
2873
2874StoreRef RegionStoreManager::removeDeadBindings(Store store,
2875 const StackFrameContext *LCtx,
2876 SymbolReaper& SymReaper) {
2877 RegionBindingsRef B = getRegionBindings(store);
2878 RemoveDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
2879 W.GenerateClusters();
2880
2881 // Enqueue the region roots onto the worklist.
2882 for (const MemRegion *Reg : SymReaper.regions()) {
2883 W.AddToWorkList(R: Reg);
2884 }
2885
2886 do W.RunWorkList(); while (W.UpdatePostponed());
2887
2888 // We have now scanned the store, marking reachable regions and symbols
2889 // as live. We now remove all the regions that are dead from the store
2890 // as well as update DSymbols with the set symbols that are now dead.
2891 for (const MemRegion *Base : llvm::make_first_range(c&: B)) {
2892 // If the cluster has been visited, we know the region has been marked.
2893 // Otherwise, remove the dead entry.
2894 if (!W.isVisited(R: Base))
2895 B = B.remove(K: Base);
2896 }
2897
2898 return StoreRef(B.asStore(), *this);
2899}
2900
2901//===----------------------------------------------------------------------===//
2902// Utility methods.
2903//===----------------------------------------------------------------------===//
2904
2905void RegionStoreManager::printJson(raw_ostream &Out, Store S, const char *NL,
2906 unsigned int Space, bool IsDot) const {
2907 RegionBindingsRef Bindings = getRegionBindings(store: S);
2908
2909 Indent(Out, Space, IsDot) << "\"store\": ";
2910
2911 if (Bindings.isEmpty()) {
2912 Out << "null," << NL;
2913 return;
2914 }
2915
2916 Out << "{ \"pointer\": \"" << Bindings.asStore() << "\", \"items\": [" << NL;
2917 Bindings.printJson(Out, NL, Space: Space + 1, IsDot);
2918 Indent(Out, Space, IsDot) << "]}," << NL;
2919}
2920