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/AnalysisDeclContext.h"
21	#include "clang/Basic/JsonSupport.h"
22	#include "clang/Basic/TargetInfo.h"
23	#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
24	#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
25	#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
26	#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
27	#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
28	#include "llvm/ADT/ImmutableMap.h"
29	#include "llvm/ADT/STLExtras.h"
30	#include "llvm/Support/TimeProfiler.h"
31	#include "llvm/Support/raw_ostream.h"
32	#include <limits>
33	#include <optional>
34	#include <utility>
35
36	using namespace clang;
37	using namespace ento;
38
39	//===----------------------------------------------------------------------===//
40	// Representation of binding keys.
41	//===----------------------------------------------------------------------===//
42
43	namespace {
44	class BindingKey {
45	public:
46	enum Kind { Default = 0x0, Direct = 0x1 };
47	private:
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	}
70
71	public:
72	bool isDirect() const { return P.getInt() & Direct; }
73	bool isDefault() const { return !isDirect(); }
74	bool hasSymbolicOffset() const { return P.getInt() & Symbolic; }
75
76	const MemRegion *getRegion() const { return P.getPointer(); }
77	uint64_t getOffset() const {
78	assert(!hasSymbolicOffset());
79	return Data;
80	}
81
82	const SubRegion *getConcreteOffsetRegion() const {
83	assert(hasSymbolicOffset());
84	return reinterpret_cast<const SubRegion *>(static_cast<uintptr_t>(Data));
85	}
86
87	const MemRegion *getBaseRegion() const {
88	if (hasSymbolicOffset())
89	return getConcreteOffsetRegion()->getBaseRegion();
90	return getRegion()->getBaseRegion();
91	}
92
93	void Profile(llvm::FoldingSetNodeID& ID) const {
94	ID.AddPointer(Ptr: P.getOpaqueValue());
95	ID.AddInteger(I: Data);
96	}
97
98	static BindingKey Make(const MemRegion *R, Kind k);
99
100	bool operator<(const BindingKey &X) const {
101	if (P.getOpaqueValue() < X.P.getOpaqueValue())
102	return true;
103	if (P.getOpaqueValue() > X.P.getOpaqueValue())
104	return false;
105	return Data < X.Data;
106	}
107
108	bool operator==(const BindingKey &X) const {
109	return P.getOpaqueValue() == X.P.getOpaqueValue() &&
110	Data == X.Data;
111	}
112
113	LLVM_DUMP_METHOD void dump() const;
114	};
115
116	std::string locDescr(Loc L) {
117	std::string S;
118	llvm::raw_string_ostream OS(S);
119	L.dumpToStream(Out&: OS);
120	return OS.str();
121	}
122	} // end anonymous namespace
123
124	BindingKey BindingKey::Make(const MemRegion *R, Kind k) {
125	const RegionOffset &RO = R->getAsOffset();
126	if (RO.hasSymbolicOffset())
127	return BindingKey(cast<SubRegion>(Val: R), cast<SubRegion>(Val: RO.getRegion()), k);
128
129	return BindingKey(RO.getRegion(), RO.getOffset(), k);
130	}
131
132	namespace llvm {
133	static inline raw_ostream &operator<<(raw_ostream &Out, BindingKey K) {
134	Out << "\"kind\": \"" << (K.isDirect() ? "Direct" : "Default")
135	<< "\", \"offset\": ";
136
137	if (!K.hasSymbolicOffset())
138	Out << K.getOffset();
139	else
140	Out << "null";
141
142	return Out;
143	}
144
145	} // namespace llvm
146
147	#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
148	void BindingKey::dump() const { llvm::errs() << *this; }
149	#endif
150
151	//===----------------------------------------------------------------------===//
152	// Actual Store type.
153	//===----------------------------------------------------------------------===//
154
155	typedef llvm::ImmutableMap<BindingKey, SVal> ClusterBindings;
156	typedef llvm::ImmutableMapRef<BindingKey, SVal> ClusterBindingsRef;
157	typedef std::pair<BindingKey, SVal> BindingPair;
158
159	typedef llvm::ImmutableMap<const MemRegion *, ClusterBindings>
160	RegionBindings;
161
162	namespace {
163	class RegionBindingsRef : public llvm::ImmutableMapRef<const MemRegion *,
164	ClusterBindings> {
165	ClusterBindings::Factory *CBFactory;
166
167	// This flag indicates whether the current bindings are within the analysis
168	// that has started from main(). It affects how we perform loads from
169	// global variables that have initializers: if we have observed the
170	// program execution from the start and we know that these variables
171	// have not been overwritten yet, we can be sure that their initializers
172	// are still relevant. This flag never gets changed when the bindings are
173	// updated, so it could potentially be moved into RegionStoreManager
174	// (as if it's the same bindings but a different loading procedure)
175	// however that would have made the manager needlessly stateful.
176	bool IsMainAnalysis;
177
178	public:
179	typedef llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>
180	ParentTy;
181
182	RegionBindingsRef(ClusterBindings::Factory &CBFactory,
183	const RegionBindings::TreeTy *T,
184	RegionBindings::TreeTy::Factory *F, bool IsMainAnalysis)
185	: RegionBindingsRef(ParentTy(T, F), CBFactory, IsMainAnalysis) {}
186
187	RegionBindingsRef(const ParentTy &P, ClusterBindings::Factory &CBFactory,
188	bool IsMainAnalysis)
189	: ParentTy(P), CBFactory(&CBFactory), IsMainAnalysis(IsMainAnalysis) {}
190
191	RegionBindingsRef removeCluster(const MemRegion *BaseRegion) const {
192	return RegionBindingsRef(ParentTy::remove(K: BaseRegion), *CBFactory,
193	IsMainAnalysis);
194	}
195
196	RegionBindingsRef addBinding(BindingKey K, SVal V) const;
197
198	RegionBindingsRef addBinding(const MemRegion *R,
199	BindingKey::Kind k, SVal V) const;
200
201	const SVal *lookup(BindingKey K) const;
202	const SVal *lookup(const MemRegion *R, BindingKey::Kind k) const;
203	using llvm::ImmutableMapRef<const MemRegion *, ClusterBindings>::lookup;
204
205	RegionBindingsRef removeBinding(BindingKey K);
206
207	RegionBindingsRef removeBinding(const MemRegion *R,
208	BindingKey::Kind k);
209
210	RegionBindingsRef removeBinding(const MemRegion *R) {
211	return removeBinding(R, k: BindingKey::Direct).
212	removeBinding(R, k: BindingKey::Default);
213	}
214
215	std::optional<SVal> getDirectBinding(const MemRegion *R) const;
216
217	/// getDefaultBinding - Returns an SVal* representing an optional default
218	/// binding associated with a region and its subregions.
219	std::optional<SVal> getDefaultBinding(const MemRegion *R) const;
220
221	/// Return the internal tree as a Store.
222	Store asStore() const {
223	llvm::PointerIntPair<Store, 1, bool> Ptr = {
224	asImmutableMap().getRootWithoutRetain(), IsMainAnalysis};
225	return reinterpret_cast<Store>(Ptr.getOpaqueValue());
226	}
227
228	bool isMainAnalysis() const {
229	return IsMainAnalysis;
230	}
231
232	void printJson(raw_ostream &Out, const char *NL = "\n",
233	unsigned int Space = 0, bool IsDot = false) const {
234	using namespace llvm;
235	DenseMap<const MemRegion *, std::string> StringifyCache;
236	auto ToString = [&StringifyCache](const MemRegion *R) {
237	auto [Place, Inserted] = StringifyCache.try_emplace(Key: R);
238	if (!Inserted)
239	return Place->second;
240	std::string Res;
241	raw_string_ostream OS(Res);
242	OS << R;
243	Place->second = Res;
244	return Res;
245	};
246
247	using Cluster =
248	std::pair<const MemRegion *, ImmutableMap<BindingKey, SVal>>;
249	using Binding = std::pair<BindingKey, SVal>;
250
251	const auto MemSpaceBeforeRegionName = [&ToString](const Cluster *L,
252	const Cluster *R) {
253	if (isa<MemSpaceRegion>(Val: L->first) && !isa<MemSpaceRegion>(Val: R->first))
254	return true;
255	if (!isa<MemSpaceRegion>(Val: L->first) && isa<MemSpaceRegion>(Val: R->first))
256	return false;
257	return ToString(L->first) < ToString(R->first);
258	};
259
260	const auto SymbolicBeforeOffset = [&ToString](const BindingKey &L,
261	const BindingKey &R) {
262	if (L.hasSymbolicOffset() && !R.hasSymbolicOffset())
263	return true;
264	if (!L.hasSymbolicOffset() && R.hasSymbolicOffset())
265	return false;
266	if (L.hasSymbolicOffset() && R.hasSymbolicOffset())
267	return ToString(L.getRegion()) < ToString(R.getRegion());
268	return L.getOffset() < R.getOffset();
269	};
270
271	const auto DefaultBindingBeforeDirectBindings =
272	[&SymbolicBeforeOffset](const Binding *LPtr, const Binding *RPtr) {
273	const BindingKey &L = LPtr->first;
274	const BindingKey &R = RPtr->first;
275	if (L.isDefault() && !R.isDefault())
276	return true;
277	if (!L.isDefault() && R.isDefault())
278	return false;
279	assert(L.isDefault() == R.isDefault());
280	return SymbolicBeforeOffset(L, R);
281	};
282
283	const auto AddrOf = [](const auto &Item) { return &Item; };
284
285	std::vector<const Cluster *> SortedClusters;
286	SortedClusters.reserve(n: std::distance(first: begin(), last: end()));
287	append_range(C&: SortedClusters, R: map_range(C: *this, F: AddrOf));
288	llvm::sort(C&: SortedClusters, Comp: MemSpaceBeforeRegionName);
289
290	for (auto [Idx, C] : llvm::enumerate(First&: SortedClusters)) {
291	const auto &[BaseRegion, Bindings] = *C;
292	Indent(Out, Space, IsDot)
293	<< "{ \"cluster\": \"" << BaseRegion << "\", \"pointer\": \""
294	<< (const void *)BaseRegion << "\", \"items\": [" << NL;
295
296	std::vector<const Binding *> SortedBindings;
297	SortedBindings.reserve(n: std::distance(first: Bindings.begin(), last: Bindings.end()));
298	append_range(C&: SortedBindings, R: map_range(C: Bindings, F: AddrOf));
299	llvm::sort(C&: SortedBindings, Comp: DefaultBindingBeforeDirectBindings);
300
301	++Space;
302	for (auto [Idx, B] : llvm::enumerate(First&: SortedBindings)) {
303	const auto &[Key, Value] = *B;
304	Indent(Out, Space, IsDot) << "{ " << Key << ", \"value\": ";
305	Value.printJson(Out, /*AddQuotes=*/true);
306	Out << " }";
307	if (Idx != SortedBindings.size() - 1)
308	Out << ',';
309	Out << NL;
310	}
311	--Space;
312	Indent(Out, Space, IsDot) << "]}";
313	if (Idx != SortedClusters.size() - 1)
314	Out << ',';
315	Out << NL;
316	}
317	}
318
319	LLVM_DUMP_METHOD void dump() const { printJson(Out&: llvm::errs()); }
320
321	protected:
322	RegionBindingsRef
323	commitBindingsToCluster(const MemRegion *BaseRegion,
324	const ClusterBindings &Bindings) const;
325	};
326	} // end anonymous namespace
327
328	/// This class represents the same as \c RegionBindingsRef, but with a limit on
329	/// the number of bindings that can be added.
330	class LimitedRegionBindingsRef : public RegionBindingsRef {
331	public:
332	LimitedRegionBindingsRef(RegionBindingsRef Base,
333	SmallVectorImpl<SVal> &EscapedValuesDuringBind,
334	std::optional<unsigned> BindingsLeft)
335	: RegionBindingsRef(Base),
336	EscapedValuesDuringBind(&EscapedValuesDuringBind),
337	BindingsLeft(BindingsLeft) {}
338
339	bool hasExhaustedBindingLimit() const {
340	return BindingsLeft.has_value() && BindingsLeft.value() == 0;
341	}
342
343	LimitedRegionBindingsRef withValuesEscaped(SVal V) const {
344	EscapedValuesDuringBind->push_back(Elt: V);
345	return *this;
346	}
347
348	LimitedRegionBindingsRef
349	withValuesEscaped(nonloc::CompoundVal::iterator Begin,
350	nonloc::CompoundVal::iterator End) const {
351	for (SVal V : llvm::make_range(x: Begin, y: End))
352	withValuesEscaped(V);
353	return *this;
354	}
355
356	LimitedRegionBindingsRef
357	addWithoutDecreasingLimit(const MemRegion *BaseRegion,
358	data_type_ref BindingKeyAndValue) const {
359	return LimitedRegionBindingsRef{RegionBindingsRef::commitBindingsToCluster(
360	BaseRegion, Bindings: BindingKeyAndValue),
361	*EscapedValuesDuringBind, BindingsLeft};
362	}
363
364	LimitedRegionBindingsRef removeCluster(const MemRegion *BaseRegion) const {
365	return LimitedRegionBindingsRef{
366	RegionBindingsRef::removeCluster(BaseRegion), *EscapedValuesDuringBind,
367	BindingsLeft};
368	}
369
370	LimitedRegionBindingsRef addBinding(BindingKey K, SVal V) const {
371	std::optional<unsigned> NewBindingsLeft = BindingsLeft;
372	if (NewBindingsLeft.has_value()) {
373	assert(NewBindingsLeft.value() != 0);
374	NewBindingsLeft.value() -= 1;
375
376	// If we just exhausted the binding limit, highjack
377	// this bind call for the default binding.
378	if (NewBindingsLeft.value() == 0) {
379	withValuesEscaped(V);
380	K = BindingKey::Make(R: K.getRegion(), k: BindingKey::Default);
381	V = UnknownVal();
382	}
383	}
384
385	return LimitedRegionBindingsRef{RegionBindingsRef::addBinding(K, V),
386	*EscapedValuesDuringBind, NewBindingsLeft};
387	}
388
389	LimitedRegionBindingsRef addBinding(const MemRegion *R, BindingKey::Kind k,
390	SVal V) const {
391	return addBinding(K: BindingKey::Make(R, k), V);
392	}
393
394	private:
395	SmallVectorImpl<SVal> *EscapedValuesDuringBind; // nonnull
396	std::optional<unsigned> BindingsLeft;
397	};
398
399	typedef const RegionBindingsRef& RegionBindingsConstRef;
400	typedef const LimitedRegionBindingsRef &LimitedRegionBindingsConstRef;
401
402	std::optional<SVal>
403	RegionBindingsRef::getDirectBinding(const MemRegion *R) const {
404	const SVal *V = lookup(R, k: BindingKey::Direct);
405	return V ? std::optional<SVal>(*V) : std::nullopt;
406	}
407
408	std::optional<SVal>
409	RegionBindingsRef::getDefaultBinding(const MemRegion *R) const {
410	const SVal *V = lookup(R, k: BindingKey::Default);
411	return V ? std::optional<SVal>(*V) : std::nullopt;
412	}
413
414	RegionBindingsRef RegionBindingsRef::commitBindingsToCluster(
415	const MemRegion *BaseRegion, const ClusterBindings &Bindings) const {
416	return RegionBindingsRef(ParentTy::add(K: BaseRegion, D: Bindings), *CBFactory,
417	IsMainAnalysis);
418	}
419
420	RegionBindingsRef RegionBindingsRef::addBinding(BindingKey K, SVal V) const {
421	const MemRegion *Base = K.getBaseRegion();
422
423	const ClusterBindings *ExistingCluster = lookup(K: Base);
424	ClusterBindings Bindings =
425	(ExistingCluster ? *ExistingCluster : CBFactory->getEmptyMap());
426	Bindings = CBFactory->add(Old: Bindings, K, D: V);
427	return commitBindingsToCluster(BaseRegion: Base, Bindings);
428	}
429
430	RegionBindingsRef RegionBindingsRef::addBinding(const MemRegion *R,
431	BindingKey::Kind k,
432	SVal V) const {
433	return addBinding(K: BindingKey::Make(R, k), V);
434	}
435
436	const SVal *RegionBindingsRef::lookup(BindingKey K) const {
437	const ClusterBindings *Cluster = lookup(K: K.getBaseRegion());
438	if (!Cluster)
439	return nullptr;
440	return Cluster->lookup(K);
441	}
442
443	const SVal *RegionBindingsRef::lookup(const MemRegion *R,
444	BindingKey::Kind k) const {
445	return lookup(K: BindingKey::Make(R, k));
446	}
447
448	RegionBindingsRef RegionBindingsRef::removeBinding(BindingKey K) {
449	const MemRegion *Base = K.getBaseRegion();
450	const ClusterBindings *Cluster = lookup(K: Base);
451	if (!Cluster)
452	return *this;
453
454	ClusterBindings NewCluster = CBFactory->remove(Old: *Cluster, K);
455	if (NewCluster.isEmpty())
456	return removeCluster(BaseRegion: Base);
457	return commitBindingsToCluster(BaseRegion: Base, Bindings: NewCluster);
458	}
459
460	RegionBindingsRef RegionBindingsRef::removeBinding(const MemRegion *R,
461	BindingKey::Kind k){
462	return removeBinding(K: BindingKey::Make(R, k));
463	}
464
465	//===----------------------------------------------------------------------===//
466	// Main RegionStore logic.
467	//===----------------------------------------------------------------------===//
468
469	namespace {
470	class InvalidateRegionsWorker;
471
472	class RegionStoreManager : public StoreManager {
473	public:
474	RegionBindings::Factory RBFactory;
475	mutable ClusterBindings::Factory CBFactory;
476
477	typedef std::vector<SVal> SValListTy;
478	private:
479	typedef llvm::DenseMap<const LazyCompoundValData *,
480	SValListTy> LazyBindingsMapTy;
481	LazyBindingsMapTy LazyBindingsMap;
482
483	/// The largest number of fields a struct can have and still be
484	/// considered "small".
485	///
486	/// This is currently used to decide whether or not it is worth "forcing" a
487	/// LazyCompoundVal on bind.
488	///
489	/// This is controlled by 'region-store-small-struct-limit' option.
490	/// To disable all small-struct-dependent behavior, set the option to "0".
491	const unsigned SmallStructLimit;
492
493	/// The largest number of element an array can have and still be
494	/// considered "small".
495	///
496	/// This is currently used to decide whether or not it is worth "forcing" a
497	/// LazyCompoundVal on bind.
498	///
499	/// This is controlled by 'region-store-small-struct-limit' option.
500	/// To disable all small-struct-dependent behavior, set the option to "0".
501	const unsigned SmallArrayLimit;
502
503	/// The number of bindings a single bind operation can scatter into.
504	/// For example, binding the initializer-list of an array would recurse and
505	/// bind all the individual array elements, potentially causing scalability
506	/// issues. Nullopt if the limit is disabled.
507	const std::optional<unsigned> RegionStoreMaxBindingFanOutPlusOne;
508
509	/// A helper used to populate the work list with the given set of
510	/// regions.
511	void populateWorkList(InvalidateRegionsWorker &W,
512	ArrayRef<SVal> Values,
513	InvalidatedRegions *TopLevelRegions);
514
515	const AnalyzerOptions &getOptions() {
516	return StateMgr.getOwningEngine().getAnalysisManager().options;
517	}
518
519	public:
520	RegionStoreManager(ProgramStateManager &mgr)
521	: StoreManager(mgr), RBFactory(mgr.getAllocator()),
522	CBFactory(mgr.getAllocator()),
523	SmallStructLimit(getOptions().RegionStoreSmallStructLimit),
524	SmallArrayLimit(getOptions().RegionStoreSmallArrayLimit),
525	RegionStoreMaxBindingFanOutPlusOne([&]() -> std::optional<unsigned> {
526	unsigned FanOut = getOptions().RegionStoreMaxBindingFanOut;
527	assert(FanOut != std::numeric_limits<unsigned>::max());
528	if (FanOut == 0)
529	return std::nullopt;
530	return FanOut + 1 /*for the default binding*/;
531	}()) {}
532
533	/// setImplicitDefaultValue - Set the default binding for the provided
534	/// MemRegion to the value implicitly defined for compound literals when
535	/// the value is not specified.
536	LimitedRegionBindingsRef
537	setImplicitDefaultValue(LimitedRegionBindingsConstRef B, const MemRegion *R,
538	QualType T);
539
540	/// ArrayToPointer - Emulates the "decay" of an array to a pointer
541	/// type. 'Array' represents the lvalue of the array being decayed
542	/// to a pointer, and the returned SVal represents the decayed
543	/// version of that lvalue (i.e., a pointer to the first element of
544	/// the array). This is called by ExprEngine when evaluating
545	/// casts from arrays to pointers.
546	SVal ArrayToPointer(Loc Array, QualType ElementTy) override;
547
548	/// Creates the Store that correctly represents memory contents before
549	/// the beginning of the analysis of the given top-level stack frame.
550	StoreRef getInitialStore(const LocationContext *InitLoc) override {
551	bool IsMainAnalysis = false;
552	if (const auto *FD = dyn_cast<FunctionDecl>(Val: InitLoc->getDecl()))
553	IsMainAnalysis = FD->isMain() && !Ctx.getLangOpts().CPlusPlus;
554	return StoreRef(RegionBindingsRef(RegionBindingsRef::ParentTy(
555	RBFactory.getEmptyMap(), RBFactory),
556	CBFactory, IsMainAnalysis)
557	.asStore(),
558	*this);
559	}
560
561	//===-------------------------------------------------------------------===//
562	// Binding values to regions.
563	//===-------------------------------------------------------------------===//
564	RegionBindingsRef
565	invalidateGlobalRegion(MemRegion::Kind K, ConstCFGElementRef Elem,
566	unsigned Count, const LocationContext *LCtx,
567	RegionBindingsRef B, InvalidatedRegions *Invalidated);
568
569	StoreRef invalidateRegions(Store store, ArrayRef<SVal> Values,
570	ConstCFGElementRef Elem, unsigned Count,
571	const LocationContext *LCtx, const CallEvent *Call,
572	InvalidatedSymbols &IS,
573	RegionAndSymbolInvalidationTraits &ITraits,
574	InvalidatedRegions *Invalidated,
575	InvalidatedRegions *InvalidatedTopLevel) override;
576
577	bool scanReachableSymbols(Store S, const MemRegion *R,
578	ScanReachableSymbols &Callbacks) override;
579
580	LimitedRegionBindingsRef
581	removeSubRegionBindings(LimitedRegionBindingsConstRef B, const SubRegion *R);
582	std::optional<SVal>
583	getConstantValFromConstArrayInitializer(RegionBindingsConstRef B,
584	const ElementRegion *R);
585	std::optional<SVal>
586	getSValFromInitListExpr(const InitListExpr *ILE,
587	const SmallVector<uint64_t, 2> &ConcreteOffsets,
588	QualType ElemT);
589	SVal getSValFromStringLiteral(const StringLiteral *SL, uint64_t Offset,
590	QualType ElemT);
591
592	public: // Part of public interface to class.
593	BindResult Bind(Store store, Loc LV, SVal V) override {
594	llvm::SmallVector<SVal, 0> EscapedValuesDuringBind;
595	LimitedRegionBindingsRef BoundedBindings =
596	getRegionBindings(store, EscapedValuesDuringBind);
597	return BindResult{.ResultingStore: StoreRef(bind(B: BoundedBindings, LV, V).asStore(), *this),
598	.FailedToBindValues: std::move(EscapedValuesDuringBind)};
599	}
600
601	LimitedRegionBindingsRef bind(LimitedRegionBindingsConstRef B, Loc LV,
602	SVal V);
603
604	// BindDefaultInitial is only used to initialize a region with
605	// a default value.
606	BindResult BindDefaultInitial(Store store, const MemRegion *R,
607	SVal V) override {
608	RegionBindingsRef B = getRegionBindings(store);
609	// Use other APIs when you have to wipe the region that was initialized
610	// earlier.
611	assert(!(B.getDefaultBinding(R) || B.getDirectBinding(R)) &&
612	"Double initialization!");
613	B = B.addBinding(K: BindingKey::Make(R, k: BindingKey::Default), V);
614	return BindResult{
615	.ResultingStore: StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this), .FailedToBindValues: {}};
616	}
617
618	// BindDefaultZero is used for zeroing constructors that may accidentally
619	// overwrite existing bindings.
620	BindResult BindDefaultZero(Store store, const MemRegion *R) override {
621	// FIXME: The offsets of empty bases can be tricky because of
622	// of the so called "empty base class optimization".
623	// If a base class has been optimized out
624	// we should not try to create a binding, otherwise we should.
625	// Unfortunately, at the moment ASTRecordLayout doesn't expose
626	// the actual sizes of the empty bases
627	// and trying to infer them from offsets/alignments
628	// seems to be error-prone and non-trivial because of the trailing padding.
629	// As a temporary mitigation we don't create bindings for empty bases.
630	if (const auto *BR = dyn_cast<CXXBaseObjectRegion>(Val: R))
631	if (BR->getDecl()->isEmpty())
632	return BindResult{.ResultingStore: StoreRef(store, *this), .FailedToBindValues: {}};
633
634	llvm::SmallVector<SVal, 0> EscapedValuesDuringBind;
635	LimitedRegionBindingsRef B =
636	getRegionBindings(store, EscapedValuesDuringBind);
637	SVal V = svalBuilder.makeZeroVal(type: Ctx.CharTy);
638	B = removeSubRegionBindings(B, R: cast<SubRegion>(Val: R));
639	B = B.addBinding(K: BindingKey::Make(R, k: BindingKey::Default), V);
640	return BindResult{
641	.ResultingStore: StoreRef(B.asImmutableMap().getRootWithoutRetain(), *this),
642	.FailedToBindValues: std::move(EscapedValuesDuringBind)};
643	}
644
645	/// Attempt to extract the fields of \p LCV and bind them to the struct region
646	/// \p R.
647	///
648	/// This path is used when it seems advantageous to "force" loading the values
649	/// within a LazyCompoundVal to bind memberwise to the struct region, rather
650	/// than using a Default binding at the base of the entire region. This is a
651	/// heuristic attempting to avoid building long chains of LazyCompoundVals.
652	///
653	/// \returns The updated store bindings, or \c std::nullopt if binding
654	/// non-lazily would be too expensive.
655	std::optional<LimitedRegionBindingsRef>
656	tryBindSmallStruct(LimitedRegionBindingsConstRef B, const TypedValueRegion *R,
657	const RecordDecl *RD, nonloc::LazyCompoundVal LCV);
658
659	/// BindStruct - Bind a compound value to a structure.
660	LimitedRegionBindingsRef bindStruct(LimitedRegionBindingsConstRef B,
661	const TypedValueRegion *R, SVal V);
662
663	/// BindVector - Bind a compound value to a vector.
664	LimitedRegionBindingsRef bindVector(LimitedRegionBindingsConstRef B,
665	const TypedValueRegion *R, SVal V);
666
667	std::optional<LimitedRegionBindingsRef>
668	tryBindSmallArray(LimitedRegionBindingsConstRef B, const TypedValueRegion *R,
669	const ArrayType *AT, nonloc::LazyCompoundVal LCV);
670
671	LimitedRegionBindingsRef bindArray(LimitedRegionBindingsConstRef B,
672	const TypedValueRegion *R, SVal V);
673
674	/// Clears out all bindings in the given region and assigns a new value
675	/// as a Default binding.
676	LimitedRegionBindingsRef bindAggregate(LimitedRegionBindingsConstRef B,
677	const TypedRegion *R, SVal DefaultVal);
678
679	/// Create a new store with the specified binding removed.
680	/// \param ST the original store, that is the basis for the new store.
681	/// \param L the location whose binding should be removed.
682	StoreRef killBinding(Store ST, Loc L) override;
683
684	void incrementReferenceCount(Store store) override {
685	getRegionBindings(store).manualRetain();
686	}
687
688	/// If the StoreManager supports it, decrement the reference count of
689	/// the specified Store object. If the reference count hits 0, the memory
690	/// associated with the object is recycled.
691	void decrementReferenceCount(Store store) override {
692	getRegionBindings(store).manualRelease();
693	}
694
695	bool includedInBindings(Store store, const MemRegion *region) const override;
696
697	/// Return the value bound to specified location in a given state.
698	///
699	/// The high level logic for this method is this:
700	/// getBinding (L)
701	/// if L has binding
702	/// return L's binding
703	/// else if L is in killset
704	/// return unknown
705	/// else
706	/// if L is on stack or heap
707	/// return undefined
708	/// else
709	/// return symbolic
710	SVal getBinding(Store S, Loc L, QualType T) override {
711	return getBinding(B: getRegionBindings(store: S), L, T);
712	}
713
714	std::optional<SVal> getUniqueDefaultBinding(RegionBindingsConstRef B,
715	const TypedValueRegion *R) const;
716	std::optional<SVal>
717	getUniqueDefaultBinding(nonloc::LazyCompoundVal LCV) const;
718
719	std::optional<SVal> getDefaultBinding(Store S, const MemRegion *R) override {
720	RegionBindingsRef B = getRegionBindings(store: S);
721	// Default bindings are always applied over a base region so look up the
722	// base region's default binding, otherwise the lookup will fail when R
723	// is at an offset from R->getBaseRegion().
724	return B.getDefaultBinding(R: R->getBaseRegion());
725	}
726
727	SVal getBinding(RegionBindingsConstRef B, Loc L, QualType T = QualType());
728
729	SVal getBindingForElement(RegionBindingsConstRef B, const ElementRegion *R);
730
731	SVal getBindingForField(RegionBindingsConstRef B, const FieldRegion *R);
732
733	SVal getBindingForObjCIvar(RegionBindingsConstRef B, const ObjCIvarRegion *R);
734
735	SVal getBindingForVar(RegionBindingsConstRef B, const VarRegion *R);
736
737	SVal getBindingForLazySymbol(const TypedValueRegion *R);
738
739	SVal getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
740	const TypedValueRegion *R,
741	QualType Ty);
742
743	SVal getLazyBinding(const SubRegion *LazyBindingRegion,
744	RegionBindingsRef LazyBinding);
745
746	/// Get bindings for the values in a struct and return a CompoundVal, used
747	/// when doing struct copy:
748	/// struct s x, y;
749	/// x = y;
750	/// y's value is retrieved by this method.
751	SVal getBindingForStruct(RegionBindingsConstRef B, const TypedValueRegion *R);
752	SVal getBindingForArray(RegionBindingsConstRef B, const TypedValueRegion *R);
753	NonLoc createLazyBinding(RegionBindingsConstRef B, const TypedValueRegion *R);
754
755	/// Used to lazily generate derived symbols for bindings that are defined
756	/// implicitly by default bindings in a super region.
757	///
758	/// Note that callers may need to specially handle LazyCompoundVals, which
759	/// are returned as is in case the caller needs to treat them differently.
760	std::optional<SVal>
761	getBindingForDerivedDefaultValue(RegionBindingsConstRef B,
762	const MemRegion *superR,
763	const TypedValueRegion *R, QualType Ty);
764
765	/// Get the state and region whose binding this region \p R corresponds to.
766	///
767	/// If there is no lazy binding for \p R, the returned value will have a null
768	/// \c second. Note that a null pointer can represents a valid Store.
769	std::pair<Store, const SubRegion *>
770	findLazyBinding(RegionBindingsConstRef B, const SubRegion *R,
771	const SubRegion *originalRegion);
772
773	/// Returns the cached set of interesting SVals contained within a lazy
774	/// binding.
775	///
776	/// The precise value of "interesting" is determined for the purposes of
777	/// RegionStore's internal analysis. It must always contain all regions and
778	/// symbols, but may omit constants and other kinds of SVal.
779	///
780	/// In contrast to compound values, LazyCompoundVals are also added
781	/// to the 'interesting values' list in addition to the child interesting
782	/// values.
783	const SValListTy &getInterestingValues(nonloc::LazyCompoundVal LCV);
784
785	//===------------------------------------------------------------------===//
786	// State pruning.
787	//===------------------------------------------------------------------===//
788
789	/// removeDeadBindings - Scans the RegionStore of 'state' for dead values.
790	/// It returns a new Store with these values removed.
791	StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
792	SymbolReaper& SymReaper) override;
793
794	//===------------------------------------------------------------------===//
795	// Utility methods.
796	//===------------------------------------------------------------------===//
797
798	RegionBindingsRef getRegionBindings(Store store) const {
799	llvm::PointerIntPair<Store, 1, bool> Ptr;
800	Ptr.setFromOpaqueValue(const_cast<void *>(store));
801	return {CBFactory,
802	static_cast<const RegionBindings::TreeTy *>(Ptr.getPointer()),
803	RBFactory.getTreeFactory(), Ptr.getInt()};
804	}
805
806	LimitedRegionBindingsRef
807	getRegionBindings(Store store,
808	SmallVectorImpl<SVal> &EscapedValuesDuringBind) const {
809	return LimitedRegionBindingsRef(
810	getRegionBindings(store), EscapedValuesDuringBind,
811	/*BindingsLeft=*/RegionStoreMaxBindingFanOutPlusOne);
812	}
813
814	void printJson(raw_ostream &Out, Store S, const char *NL = "\n",
815	unsigned int Space = 0, bool IsDot = false) const override;
816
817	void iterBindings(Store store, BindingsHandler& f) override {
818	RegionBindingsRef B = getRegionBindings(store);
819	for (const auto &[Region, Cluster] : B) {
820	for (const auto &[Key, Value] : Cluster) {
821	if (!Key.isDirect())
822	continue;
823	if (const SubRegion *R = dyn_cast<SubRegion>(Val: Key.getRegion())) {
824	// FIXME: Possibly incorporate the offset?
825	if (!f.HandleBinding(SMgr&: *this, store, region: R, val: Value))
826	return;
827	}
828	}
829	}
830	}
831	};
832
833	} // end anonymous namespace
834
835	//===----------------------------------------------------------------------===//
836	// RegionStore creation.
837	//===----------------------------------------------------------------------===//
838
839	std::unique_ptr<StoreManager>
840	ento::CreateRegionStoreManager(ProgramStateManager &StMgr) {
841	return std::make_unique<RegionStoreManager>(args&: StMgr);
842	}
843
844	//===----------------------------------------------------------------------===//
845	// Region Cluster analysis.
846	//===----------------------------------------------------------------------===//
847
848	namespace {
849	/// Used to determine which global regions are automatically included in the
850	/// initial worklist of a ClusterAnalysis.
851	enum GlobalsFilterKind {
852	/// Don't include any global regions.
853	GFK_None,
854	/// Only include system globals.
855	GFK_SystemOnly,
856	/// Include all global regions.
857	GFK_All
858	};
859
860	template <typename DERIVED>
861	class ClusterAnalysis {
862	protected:
863	typedef llvm::DenseMap<const MemRegion *, const ClusterBindings *> ClusterMap;
864	typedef const MemRegion * WorkListElement;
865	typedef SmallVector<WorkListElement, 10> WorkList;
866
867	llvm::SmallPtrSet<const ClusterBindings *, 16> Visited;
868
869	WorkList WL;
870
871	RegionStoreManager &RM;
872	ASTContext &Ctx;
873	SValBuilder &svalBuilder;
874
875	RegionBindingsRef B;
876
877
878	protected:
879	const ClusterBindings *getCluster(const MemRegion *R) {
880	return B.lookup(K: R);
881	}
882
883	/// Returns true if all clusters in the given memspace should be initially
884	/// included in the cluster analysis. Subclasses may provide their
885	/// own implementation.
886	bool includeEntireMemorySpace(const MemRegion *Base) {
887	return false;
888	}
889
890	public:
891	ClusterAnalysis(RegionStoreManager &rm, ProgramStateManager &StateMgr,
892	RegionBindingsRef b)
893	: RM(rm), Ctx(StateMgr.getContext()),
894	svalBuilder(StateMgr.getSValBuilder()), B(std::move(b)) {}
895
896	RegionBindingsRef getRegionBindings() const { return B; }
897
898	bool isVisited(const MemRegion *R) {
899	return Visited.count(Ptr: getCluster(R));
900	}
901
902	void GenerateClusters() {
903	// Scan the entire set of bindings and record the region clusters.
904	for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end();
905	RI != RE; ++RI){
906	const MemRegion *Base = RI.getKey();
907
908	const ClusterBindings &Cluster = RI.getData();
909	assert(!Cluster.isEmpty() && "Empty clusters should be removed");
910	static_cast<DERIVED*>(this)->VisitAddedToCluster(Base, Cluster);
911
912	// If the base's memspace should be entirely invalidated, add the cluster
913	// to the workspace up front.
914	if (static_cast<DERIVED*>(this)->includeEntireMemorySpace(Base))
915	AddToWorkList(WorkListElement(Base), &Cluster);
916	}
917	}
918
919	bool AddToWorkList(WorkListElement E, const ClusterBindings *C) {
920	if (C && !Visited.insert(Ptr: C).second)
921	return false;
922	WL.push_back(Elt: E);
923	return true;
924	}
925
926	bool AddToWorkList(const MemRegion *R) {
927	return static_cast<DERIVED*>(this)->AddToWorkList(R);
928	}
929
930	void RunWorkList() {
931	while (!WL.empty()) {
932	WorkListElement E = WL.pop_back_val();
933	const MemRegion *BaseR = E;
934
935	static_cast<DERIVED*>(this)->VisitCluster(BaseR, getCluster(R: BaseR));
936	}
937	}
938
939	void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C) {}
940	void VisitCluster(const MemRegion *baseR, const ClusterBindings *C) {}
941
942	void VisitCluster(const MemRegion *BaseR, const ClusterBindings *C,
943	bool Flag) {
944	static_cast<DERIVED*>(this)->VisitCluster(BaseR, C);
945	}
946	};
947	}
948
949	//===----------------------------------------------------------------------===//
950	// Binding invalidation.
951	//===----------------------------------------------------------------------===//
952
953	bool RegionStoreManager::scanReachableSymbols(Store S, const MemRegion *R,
954	ScanReachableSymbols &Callbacks) {
955	assert(R == R->getBaseRegion() && "Should only be called for base regions");
956	RegionBindingsRef B = getRegionBindings(store: S);
957	const ClusterBindings *Cluster = B.lookup(K: R);
958
959	if (!Cluster)
960	return true;
961
962	for (ClusterBindings::iterator RI = Cluster->begin(), RE = Cluster->end();
963	RI != RE; ++RI) {
964	if (!Callbacks.scan(val: RI.getData()))
965	return false;
966	}
967
968	return true;
969	}
970
971	static inline bool isUnionField(const FieldRegion *FR) {
972	return FR->getDecl()->getParent()->isUnion();
973	}
974
975	typedef SmallVector<const FieldDecl *, 8> FieldVector;
976
977	static void getSymbolicOffsetFields(BindingKey K, FieldVector &Fields) {
978	assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
979
980	const MemRegion *Base = K.getConcreteOffsetRegion();
981	const MemRegion *R = K.getRegion();
982
983	while (R != Base) {
984	if (const FieldRegion *FR = dyn_cast<FieldRegion>(Val: R))
985	if (!isUnionField(FR))
986	Fields.push_back(Elt: FR->getDecl());
987
988	R = cast<SubRegion>(Val: R)->getSuperRegion();
989	}
990	}
991
992	static bool isCompatibleWithFields(BindingKey K, const FieldVector &Fields) {
993	assert(K.hasSymbolicOffset() && "Not implemented for concrete offset keys");
994
995	if (Fields.empty())
996	return true;
997
998	FieldVector FieldsInBindingKey;
999	getSymbolicOffsetFields(K, Fields&: FieldsInBindingKey);
1000
1001	ptrdiff_t Delta = FieldsInBindingKey.size() - Fields.size();
1002	if (Delta >= 0)
1003	return std::equal(first1: FieldsInBindingKey.begin() + Delta,
1004	last1: FieldsInBindingKey.end(),
1005	first2: Fields.begin());
1006	else
1007	return std::equal(first1: FieldsInBindingKey.begin(), last1: FieldsInBindingKey.end(),
1008	first2: Fields.begin() - Delta);
1009	}
1010
1011	/// Collects all bindings in \p Cluster that may refer to bindings within
1012	/// \p Top.
1013	///
1014	/// Each binding is a pair whose \c first is the key (a BindingKey) and whose
1015	/// \c second is the value (an SVal).
1016	///
1017	/// The \p IncludeAllDefaultBindings parameter specifies whether to include
1018	/// default bindings that may extend beyond \p Top itself, e.g. if \p Top is
1019	/// an aggregate within a larger aggregate with a default binding.
1020	static void
1021	collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings,
1022	SValBuilder &SVB, const ClusterBindings &Cluster,
1023	const SubRegion *Top, BindingKey TopKey,
1024	bool IncludeAllDefaultBindings) {
1025	FieldVector FieldsInSymbolicSubregions;
1026	if (TopKey.hasSymbolicOffset()) {
1027	getSymbolicOffsetFields(K: TopKey, Fields&: FieldsInSymbolicSubregions);
1028	Top = TopKey.getConcreteOffsetRegion();
1029	TopKey = BindingKey::Make(R: Top, k: BindingKey::Default);
1030	}
1031
1032	// Find the length (in bits) of the region being invalidated.
1033	uint64_t Length = UINT64_MAX;
1034	SVal Extent = Top->getMemRegionManager().getStaticSize(MR: Top, SVB);
1035	if (std::optional<nonloc::ConcreteInt> ExtentCI =
1036	Extent.getAs<nonloc::ConcreteInt>()) {
1037	const llvm::APSInt &ExtentInt = ExtentCI->getValue();
1038	assert(ExtentInt.isNonNegative() || ExtentInt.isUnsigned());
1039	// Extents are in bytes but region offsets are in bits. Be careful!
1040	Length = ExtentInt.getLimitedValue() * SVB.getContext().getCharWidth();
1041	} else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Val: Top)) {
1042	if (FR->getDecl()->isBitField())
1043	Length = FR->getDecl()->getBitWidthValue();
1044	}
1045
1046	for (const auto &StoreEntry : Cluster) {
1047	BindingKey NextKey = StoreEntry.first;
1048	if (NextKey.getRegion() == TopKey.getRegion()) {
1049	// FIXME: This doesn't catch the case where we're really invalidating a
1050	// region with a symbolic offset. Example:
1051	// R: points[i].y
1052	// Next: points[0].x
1053
1054	if (NextKey.getOffset() > TopKey.getOffset() &&
1055	NextKey.getOffset() - TopKey.getOffset() < Length) {
1056	// Case 1: The next binding is inside the region we're invalidating.
1057	// Include it.
1058	Bindings.push_back(Elt: StoreEntry);
1059
1060	} else if (NextKey.getOffset() == TopKey.getOffset()) {
1061	// Case 2: The next binding is at the same offset as the region we're
1062	// invalidating. In this case, we need to leave default bindings alone,
1063	// since they may be providing a default value for a regions beyond what
1064	// we're invalidating.
1065	// FIXME: This is probably incorrect; consider invalidating an outer
1066	// struct whose first field is bound to a LazyCompoundVal.
1067	if (IncludeAllDefaultBindings || NextKey.isDirect())
1068	Bindings.push_back(Elt: StoreEntry);
1069	}
1070
1071	} else if (NextKey.hasSymbolicOffset()) {
1072	const MemRegion *Base = NextKey.getConcreteOffsetRegion();
1073	if (Top->isSubRegionOf(R: Base) && Top != Base) {
1074	// Case 3: The next key is symbolic and we just changed something within
1075	// its concrete region. We don't know if the binding is still valid, so
1076	// we'll be conservative and include it.
1077	if (IncludeAllDefaultBindings || NextKey.isDirect())
1078	if (isCompatibleWithFields(K: NextKey, Fields: FieldsInSymbolicSubregions))
1079	Bindings.push_back(Elt: StoreEntry);
1080	} else if (const SubRegion *BaseSR = dyn_cast<SubRegion>(Val: Base)) {
1081	// Case 4: The next key is symbolic, but we changed a known
1082	// super-region. In this case the binding is certainly included.
1083	if (BaseSR->isSubRegionOf(R: Top))
1084	if (isCompatibleWithFields(K: NextKey, Fields: FieldsInSymbolicSubregions))
1085	Bindings.push_back(Elt: StoreEntry);
1086	}
1087	}
1088	}
1089	}
1090
1091	static void
1092	collectSubRegionBindings(SmallVectorImpl<BindingPair> &Bindings,
1093	SValBuilder &SVB, const ClusterBindings &Cluster,
1094	const SubRegion *Top, bool IncludeAllDefaultBindings) {
1095	collectSubRegionBindings(Bindings, SVB, Cluster, Top,
1096	TopKey: BindingKey::Make(R: Top, k: BindingKey::Default),
1097	IncludeAllDefaultBindings);
1098	}
1099
1100	LimitedRegionBindingsRef
1101	RegionStoreManager::removeSubRegionBindings(LimitedRegionBindingsConstRef B,
1102	const SubRegion *Top) {
1103	BindingKey TopKey = BindingKey::Make(R: Top, k: BindingKey::Default);
1104	const MemRegion *ClusterHead = TopKey.getBaseRegion();
1105
1106	if (Top == ClusterHead) {
1107	// We can remove an entire cluster's bindings all in one go.
1108	return B.removeCluster(BaseRegion: Top);
1109	}
1110
1111	const ClusterBindings *Cluster = B.lookup(K: ClusterHead);
1112	if (!Cluster) {
1113	// If we're invalidating a region with a symbolic offset, we need to make
1114	// sure we don't treat the base region as uninitialized anymore.
1115	if (TopKey.hasSymbolicOffset()) {
1116	const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
1117	return B.addBinding(R: Concrete, k: BindingKey::Default, V: UnknownVal());
1118	}
1119	return B;
1120	}
1121
1122	SmallVector<BindingPair, 32> Bindings;
1123	collectSubRegionBindings(Bindings, SVB&: svalBuilder, Cluster: *Cluster, Top, TopKey,
1124	/*IncludeAllDefaultBindings=*/false);
1125
1126	ClusterBindingsRef Result(*Cluster, CBFactory);
1127	for (BindingKey Key : llvm::make_first_range(c&: Bindings))
1128	Result = Result.remove(K: Key);
1129
1130	// If we're invalidating a region with a symbolic offset, we need to make sure
1131	// we don't treat the base region as uninitialized anymore.
1132	// FIXME: This isn't very precise; see the example in
1133	// collectSubRegionBindings.
1134	if (TopKey.hasSymbolicOffset()) {
1135	const SubRegion *Concrete = TopKey.getConcreteOffsetRegion();
1136	Result = Result.add(K: BindingKey::Make(R: Concrete, k: BindingKey::Default),
1137	D: UnknownVal());
1138	}
1139
1140	if (Result.isEmpty())
1141	return B.removeCluster(BaseRegion: ClusterHead);
1142	return B.addWithoutDecreasingLimit(BaseRegion: ClusterHead, BindingKeyAndValue: Result.asImmutableMap());
1143	}
1144
1145	namespace {
1146	class InvalidateRegionsWorker : public ClusterAnalysis<InvalidateRegionsWorker>
1147	{
1148	ConstCFGElementRef Elem;
1149	unsigned Count;
1150	const LocationContext *LCtx;
1151	InvalidatedSymbols &IS;
1152	RegionAndSymbolInvalidationTraits &ITraits;
1153	StoreManager::InvalidatedRegions *Regions;
1154	GlobalsFilterKind GlobalsFilter;
1155	public:
1156	InvalidateRegionsWorker(RegionStoreManager &rm, ProgramStateManager &stateMgr,
1157	RegionBindingsRef b, ConstCFGElementRef elem,
1158	unsigned count, const LocationContext *lctx,
1159	InvalidatedSymbols &is,
1160	RegionAndSymbolInvalidationTraits &ITraitsIn,
1161	StoreManager::InvalidatedRegions *r,
1162	GlobalsFilterKind GFK)
1163	: ClusterAnalysis<InvalidateRegionsWorker>(rm, stateMgr, b), Elem(elem),
1164	Count(count), LCtx(lctx), IS(is), ITraits(ITraitsIn), Regions(r),
1165	GlobalsFilter(GFK) {}
1166
1167	void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
1168	void VisitBinding(SVal V);
1169
1170	using ClusterAnalysis::AddToWorkList;
1171
1172	bool AddToWorkList(const MemRegion *R);
1173
1174	/// Returns true if all clusters in the memory space for \p Base should be
1175	/// be invalidated.
1176	bool includeEntireMemorySpace(const MemRegion *Base);
1177
1178	/// Returns true if the memory space of the given region is one of the global
1179	/// regions specially included at the start of invalidation.
1180	bool isInitiallyIncludedGlobalRegion(const MemRegion *R);
1181	};
1182	}
1183
1184	bool InvalidateRegionsWorker::AddToWorkList(const MemRegion *R) {
1185	bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1186	MR: R, IK: RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
1187	const MemRegion *BaseR = doNotInvalidateSuperRegion ? R : R->getBaseRegion();
1188	return AddToWorkList(E: WorkListElement(BaseR), C: getCluster(R: BaseR));
1189	}
1190
1191	void InvalidateRegionsWorker::VisitBinding(SVal V) {
1192	// A symbol? Mark it touched by the invalidation.
1193	if (SymbolRef Sym = V.getAsSymbol())
1194	IS.insert(V: Sym);
1195
1196	if (const MemRegion *R = V.getAsRegion()) {
1197	AddToWorkList(R);
1198	return;
1199	}
1200
1201	// Is it a LazyCompoundVal? All references get invalidated as well.
1202	if (std::optional<nonloc::LazyCompoundVal> LCS =
1203	V.getAs<nonloc::LazyCompoundVal>()) {
1204
1205	// `getInterestingValues()` returns SVals contained within LazyCompoundVals,
1206	// so there is no need to visit them.
1207	for (SVal V : RM.getInterestingValues(LCV: *LCS))
1208	if (!isa<nonloc::LazyCompoundVal>(Val: V))
1209	VisitBinding(V);
1210
1211	return;
1212	}
1213	}
1214
1215	void InvalidateRegionsWorker::VisitCluster(const MemRegion *baseR,
1216	const ClusterBindings *C) {
1217
1218	bool PreserveRegionsContents =
1219	ITraits.hasTrait(MR: baseR,
1220	IK: RegionAndSymbolInvalidationTraits::TK_PreserveContents);
1221
1222	if (C) {
1223	for (SVal Val : llvm::make_second_range(c: *C))
1224	VisitBinding(V: Val);
1225
1226	// Invalidate regions contents.
1227	if (!PreserveRegionsContents)
1228	B = B.removeCluster(BaseRegion: baseR);
1229	}
1230
1231	if (const auto *TO = dyn_cast<TypedValueRegion>(Val: baseR)) {
1232	if (const auto *RD = TO->getValueType()->getAsCXXRecordDecl()) {
1233
1234	// Lambdas can affect all static local variables without explicitly
1235	// capturing those.
1236	// We invalidate all static locals referenced inside the lambda body.
1237	if (RD->isLambda() && RD->getLambdaCallOperator()->getBody()) {
1238	using namespace ast_matchers;
1239
1240	const char *DeclBind = "DeclBind";
1241	StatementMatcher RefToStatic = stmt(hasDescendant(declRefExpr(
1242	to(InnerMatcher: varDecl(hasStaticStorageDuration()).bind(ID: DeclBind)))));
1243	auto Matches =
1244	match(RefToStatic, *RD->getLambdaCallOperator()->getBody(),
1245	RD->getASTContext());
1246
1247	for (BoundNodes &Match : Matches) {
1248	auto *VD = Match.getNodeAs<VarDecl>(DeclBind);
1249	const VarRegion *ToInvalidate =
1250	RM.getRegionManager().getVarRegion(VD, LCtx);
1251	AddToWorkList(ToInvalidate);
1252	}
1253	}
1254	}
1255	}
1256
1257	// BlockDataRegion? If so, invalidate captured variables that are passed
1258	// by reference.
1259	if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(Val: baseR)) {
1260	for (auto Var : BR->referenced_vars()) {
1261	const VarRegion *VR = Var.getCapturedRegion();
1262	const VarDecl *VD = VR->getDecl();
1263	if (VD->hasAttr<BlocksAttr>() || !VD->hasLocalStorage()) {
1264	AddToWorkList(R: VR);
1265	}
1266	else if (Loc::isLocType(T: VR->getValueType())) {
1267	// Map the current bindings to a Store to retrieve the value
1268	// of the binding. If that binding itself is a region, we should
1269	// invalidate that region. This is because a block may capture
1270	// a pointer value, but the thing pointed by that pointer may
1271	// get invalidated.
1272	SVal V = RM.getBinding(B, L: loc::MemRegionVal(VR));
1273	if (std::optional<Loc> L = V.getAs<Loc>()) {
1274	if (const MemRegion *LR = L->getAsRegion())
1275	AddToWorkList(R: LR);
1276	}
1277	}
1278	}
1279	return;
1280	}
1281
1282	// Symbolic region?
1283	if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Val: baseR))
1284	IS.insert(V: SR->getSymbol());
1285
1286	// Nothing else should be done in the case when we preserve regions context.
1287	if (PreserveRegionsContents)
1288	return;
1289
1290	// Otherwise, we have a normal data region. Record that we touched the region.
1291	if (Regions)
1292	Regions->push_back(Elt: baseR);
1293
1294	if (isa<AllocaRegion, SymbolicRegion>(Val: baseR)) {
1295	// Invalidate the region by setting its default value to
1296	// conjured symbol. The type of the symbol is irrelevant.
1297	DefinedOrUnknownSVal V =
1298	svalBuilder.conjureSymbolVal(baseR, Elem, LCtx, Ctx.IntTy, Count);
1299	B = B.addBinding(R: baseR, k: BindingKey::Default, V);
1300	return;
1301	}
1302
1303	if (!baseR->isBoundable())
1304	return;
1305
1306	const TypedValueRegion *TR = cast<TypedValueRegion>(Val: baseR);
1307	QualType T = TR->getValueType();
1308
1309	if (isInitiallyIncludedGlobalRegion(R: baseR)) {
1310	// If the region is a global and we are invalidating all globals,
1311	// erasing the entry is good enough. This causes all globals to be lazily
1312	// symbolicated from the same base symbol.
1313	return;
1314	}
1315
1316	if (T->isRecordType()) {
1317	// Invalidate the region by setting its default value to
1318	// conjured symbol. The type of the symbol is irrelevant.
1319	DefinedOrUnknownSVal V =
1320	svalBuilder.conjureSymbolVal(baseR, Elem, LCtx, Ctx.IntTy, Count);
1321	B = B.addBinding(R: baseR, k: BindingKey::Default, V);
1322	return;
1323	}
1324
1325	if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
1326	bool doNotInvalidateSuperRegion = ITraits.hasTrait(
1327	MR: baseR,
1328	IK: RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
1329
1330	if (doNotInvalidateSuperRegion) {
1331	// We are not doing blank invalidation of the whole array region so we
1332	// have to manually invalidate each elements.
1333	std::optional<uint64_t> NumElements;
1334
1335	// Compute lower and upper offsets for region within array.
1336	if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(Val: AT))
1337	NumElements = CAT->getZExtSize();
1338	if (!NumElements) // We are not dealing with a constant size array
1339	goto conjure_default;
1340	QualType ElementTy = AT->getElementType();
1341	uint64_t ElemSize = Ctx.getTypeSize(T: ElementTy);
1342	const RegionOffset &RO = baseR->getAsOffset();
1343	const MemRegion *SuperR = baseR->getBaseRegion();
1344	if (RO.hasSymbolicOffset()) {
1345	// If base region has a symbolic offset,
1346	// we revert to invalidating the super region.
1347	if (SuperR)
1348	AddToWorkList(R: SuperR);
1349	goto conjure_default;
1350	}
1351
1352	uint64_t LowerOffset = RO.getOffset();
1353	uint64_t UpperOffset = LowerOffset + *NumElements * ElemSize;
1354	bool UpperOverflow = UpperOffset < LowerOffset;
1355
1356	// Invalidate regions which are within array boundaries,
1357	// or have a symbolic offset.
1358	if (!SuperR)
1359	goto conjure_default;
1360
1361	const ClusterBindings *C = B.lookup(K: SuperR);
1362	if (!C)
1363	goto conjure_default;
1364
1365	for (const auto &[BK, V] : *C) {
1366	std::optional<uint64_t> ROffset =
1367	BK.hasSymbolicOffset() ? std::optional<uint64_t>() : BK.getOffset();
1368
1369	// Check offset is not symbolic and within array's boundaries.
1370	// Handles arrays of 0 elements and of 0-sized elements as well.
1371	if (!ROffset ||
1372	((*ROffset >= LowerOffset && *ROffset < UpperOffset) ||
1373	(UpperOverflow &&
1374	(*ROffset >= LowerOffset || *ROffset < UpperOffset)) ||
1375	(LowerOffset == UpperOffset && *ROffset == LowerOffset))) {
1376	B = B.removeBinding(K: BK);
1377	// Bound symbolic regions need to be invalidated for dead symbol
1378	// detection.
1379	const MemRegion *R = V.getAsRegion();
1380	if (isa_and_nonnull<SymbolicRegion>(Val: R))
1381	VisitBinding(V);
1382	}
1383	}
1384	}
1385	conjure_default:
1386	// Set the default value of the array to conjured symbol.
1387	DefinedOrUnknownSVal V = svalBuilder.conjureSymbolVal(
1388	symbolTag: baseR, elem: Elem, LCtx, type: AT->getElementType(), count: Count);
1389	B = B.addBinding(R: baseR, k: BindingKey::Default, V);
1390	return;
1391	}
1392
1393	DefinedOrUnknownSVal V =
1394	svalBuilder.conjureSymbolVal(symbolTag: baseR, elem: Elem, LCtx, type: T, count: Count);
1395	assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
1396	B = B.addBinding(R: baseR, k: BindingKey::Direct, V);
1397	}
1398
1399	bool InvalidateRegionsWorker::isInitiallyIncludedGlobalRegion(
1400	const MemRegion *R) {
1401	switch (GlobalsFilter) {
1402	case GFK_None:
1403	return false;
1404	case GFK_SystemOnly:
1405	return isa<GlobalSystemSpaceRegion>(Val: R->getRawMemorySpace());
1406	case GFK_All:
1407	return isa<NonStaticGlobalSpaceRegion>(Val: R->getRawMemorySpace());
1408	}
1409
1410	llvm_unreachable("unknown globals filter");
1411	}
1412
1413	bool InvalidateRegionsWorker::includeEntireMemorySpace(const MemRegion *Base) {
1414	if (isInitiallyIncludedGlobalRegion(R: Base))
1415	return true;
1416
1417	const MemSpaceRegion *MemSpace = Base->getRawMemorySpace();
1418	return ITraits.hasTrait(MR: MemSpace,
1419	IK: RegionAndSymbolInvalidationTraits::TK_EntireMemSpace);
1420	}
1421
1422	RegionBindingsRef RegionStoreManager::invalidateGlobalRegion(
1423	MemRegion::Kind K, ConstCFGElementRef Elem, unsigned Count,
1424	const LocationContext *LCtx, RegionBindingsRef B,
1425	InvalidatedRegions *Invalidated) {
1426	// Bind the globals memory space to a new symbol that we will use to derive
1427	// the bindings for all globals.
1428	const GlobalsSpaceRegion *GS = MRMgr.getGlobalsRegion(K);
1429	SVal V = svalBuilder.conjureSymbolVal(
1430	/* symbolTag = */ (const void *)GS, Elem, LCtx,
1431	/* type does not matter */ Ctx.IntTy, Count);
1432
1433	B = B.removeBinding(R: GS)
1434	.addBinding(K: BindingKey::Make(R: GS, k: BindingKey::Default), V);
1435
1436	// Even if there are no bindings in the global scope, we still need to
1437	// record that we touched it.
1438	if (Invalidated)
1439	Invalidated->push_back(Elt: GS);
1440
1441	return B;
1442	}
1443
1444	void RegionStoreManager::populateWorkList(InvalidateRegionsWorker &W,
1445	ArrayRef<SVal> Values,
1446	InvalidatedRegions *TopLevelRegions) {
1447	for (SVal V : Values) {
1448	if (auto LCS = V.getAs<nonloc::LazyCompoundVal>()) {
1449	for (SVal S : getInterestingValues(LCV: *LCS))
1450	if (const MemRegion *R = S.getAsRegion())
1451	W.AddToWorkList(R);
1452
1453	continue;
1454	}
1455
1456	if (const MemRegion *R = V.getAsRegion()) {
1457	if (TopLevelRegions)
1458	TopLevelRegions->push_back(Elt: R);
1459	W.AddToWorkList(R);
1460	continue;
1461	}
1462	}
1463	}
1464
1465	StoreRef RegionStoreManager::invalidateRegions(
1466	Store store, ArrayRef<SVal> Values, ConstCFGElementRef Elem, unsigned Count,
1467	const LocationContext *LCtx, const CallEvent *Call, InvalidatedSymbols &IS,
1468	RegionAndSymbolInvalidationTraits &ITraits,
1469	InvalidatedRegions *TopLevelRegions, InvalidatedRegions *Invalidated) {
1470	GlobalsFilterKind GlobalsFilter;
1471	if (Call) {
1472	if (Call->isInSystemHeader())
1473	GlobalsFilter = GFK_SystemOnly;
1474	else
1475	GlobalsFilter = GFK_All;
1476	} else {
1477	GlobalsFilter = GFK_None;
1478	}
1479
1480	RegionBindingsRef B = getRegionBindings(store);
1481	InvalidateRegionsWorker W(*this, StateMgr, B, Elem, Count, LCtx, IS, ITraits,
1482	Invalidated, GlobalsFilter);
1483
1484	// Scan the bindings and generate the clusters.
1485	W.GenerateClusters();
1486
1487	// Add the regions to the worklist.
1488	populateWorkList(W, Values, TopLevelRegions);
1489
1490	W.RunWorkList();
1491
1492	// Return the new bindings.
1493	B = W.getRegionBindings();
1494
1495	// For calls, determine which global regions should be invalidated and
1496	// invalidate them. (Note that function-static and immutable globals are never
1497	// invalidated by this.)
1498	// TODO: This could possibly be more precise with modules.
1499	switch (GlobalsFilter) {
1500	case GFK_All:
1501	B = invalidateGlobalRegion(K: MemRegion::GlobalInternalSpaceRegionKind, Elem,
1502	Count, LCtx, B, Invalidated);
1503	[[fallthrough]];
1504	case GFK_SystemOnly:
1505	B = invalidateGlobalRegion(K: MemRegion::GlobalSystemSpaceRegionKind, Elem,
1506	Count, LCtx, B, Invalidated);
1507	[[fallthrough]];
1508	case GFK_None:
1509	break;
1510	}
1511
1512	return StoreRef(B.asStore(), *this);
1513	}
1514
1515	//===----------------------------------------------------------------------===//
1516	// Location and region casting.
1517	//===----------------------------------------------------------------------===//
1518
1519	/// ArrayToPointer - Emulates the "decay" of an array to a pointer
1520	/// type. 'Array' represents the lvalue of the array being decayed
1521	/// to a pointer, and the returned SVal represents the decayed
1522	/// version of that lvalue (i.e., a pointer to the first element of
1523	/// the array). This is called by ExprEngine when evaluating casts
1524	/// from arrays to pointers.
1525	SVal RegionStoreManager::ArrayToPointer(Loc Array, QualType T) {
1526	if (isa<loc::ConcreteInt>(Val: Array))
1527	return Array;
1528
1529	if (!isa<loc::MemRegionVal>(Val: Array))
1530	return UnknownVal();
1531
1532	const SubRegion *R =
1533	cast<SubRegion>(Val: Array.castAs<loc::MemRegionVal>().getRegion());
1534	NonLoc ZeroIdx = svalBuilder.makeZeroArrayIndex();
1535	return loc::MemRegionVal(MRMgr.getElementRegion(elementType: T, Idx: ZeroIdx, superRegion: R, Ctx));
1536	}
1537
1538	//===----------------------------------------------------------------------===//
1539	// Loading values from regions.
1540	//===----------------------------------------------------------------------===//
1541
1542	SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T) {
1543	assert(!isa<UnknownVal>(L) && "location unknown");
1544	assert(!isa<UndefinedVal>(L) && "location undefined");
1545
1546	// For access to concrete addresses, return UnknownVal. Checks
1547	// for null dereferences (and similar errors) are done by checkers, not
1548	// the Store.
1549	// FIXME: We can consider lazily symbolicating such memory, but we really
1550	// should defer this when we can reason easily about symbolicating arrays
1551	// of bytes.
1552	if (L.getAs<loc::ConcreteInt>()) {
1553	return UnknownVal();
1554	}
1555	if (!L.getAs<loc::MemRegionVal>()) {
1556	return UnknownVal();
1557	}
1558
1559	const MemRegion *MR = L.castAs<loc::MemRegionVal>().getRegion();
1560
1561	if (isa<BlockDataRegion>(Val: MR)) {
1562	return UnknownVal();
1563	}
1564
1565	// Auto-detect the binding type.
1566	if (T.isNull()) {
1567	if (const auto *TVR = dyn_cast<TypedValueRegion>(Val: MR))
1568	T = TVR->getValueType();
1569	else if (const auto *TR = dyn_cast<TypedRegion>(Val: MR))
1570	T = TR->getLocationType()->getPointeeType();
1571	else if (const auto *SR = dyn_cast<SymbolicRegion>(Val: MR))
1572	T = SR->getPointeeStaticType();
1573	}
1574	assert(!T.isNull() && "Unable to auto-detect binding type!");
1575	assert(!T->isVoidType() && "Attempting to dereference a void pointer!");
1576
1577	if (!isa<TypedValueRegion>(Val: MR))
1578	MR = GetElementZeroRegion(R: cast<SubRegion>(Val: MR), T);
1579
1580	// FIXME: Perhaps this method should just take a 'const MemRegion*' argument
1581	// instead of 'Loc', and have the other Loc cases handled at a higher level.
1582	const TypedValueRegion *R = cast<TypedValueRegion>(Val: MR);
1583	QualType RTy = R->getValueType();
1584
1585	// FIXME: we do not yet model the parts of a complex type, so treat the
1586	// whole thing as "unknown".
1587	if (RTy->isAnyComplexType())
1588	return UnknownVal();
1589
1590	// FIXME: We should eventually handle funny addressing. e.g.:
1591	//
1592	// int x = ...;
1593	// int *p = &x;
1594	// char *q = (char*) p;
1595	// char c = *q; // returns the first byte of 'x'.
1596	//
1597	// Such funny addressing will occur due to layering of regions.
1598	if (RTy->isStructureOrClassType())
1599	return getBindingForStruct(B, R);
1600
1601	// FIXME: Handle unions.
1602	if (RTy->isUnionType())
1603	return createLazyBinding(B, R);
1604
1605	if (RTy->isArrayType()) {
1606	if (RTy->isConstantArrayType())
1607	return getBindingForArray(B, R);
1608	else
1609	return UnknownVal();
1610	}
1611
1612	// FIXME: handle Vector types.
1613	if (RTy->isVectorType())
1614	return UnknownVal();
1615
1616	if (const FieldRegion* FR = dyn_cast<FieldRegion>(Val: R))
1617	return svalBuilder.evalCast(V: getBindingForField(B, R: FR), CastTy: T, OriginalTy: QualType{});
1618
1619	if (const ElementRegion* ER = dyn_cast<ElementRegion>(Val: R)) {
1620	// FIXME: Here we actually perform an implicit conversion from the loaded
1621	// value to the element type. Eventually we want to compose these values
1622	// more intelligently. For example, an 'element' can encompass multiple
1623	// bound regions (e.g., several bound bytes), or could be a subset of
1624	// a larger value.
1625	return svalBuilder.evalCast(V: getBindingForElement(B, R: ER), CastTy: T, OriginalTy: QualType{});
1626	}
1627
1628	if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(Val: R)) {
1629	// FIXME: Here we actually perform an implicit conversion from the loaded
1630	// value to the ivar type. What we should model is stores to ivars
1631	// that blow past the extent of the ivar. If the address of the ivar is
1632	// reinterpretted, it is possible we stored a different value that could
1633	// fit within the ivar. Either we need to cast these when storing them
1634	// or reinterpret them lazily (as we do here).
1635	return svalBuilder.evalCast(V: getBindingForObjCIvar(B, R: IVR), CastTy: T, OriginalTy: QualType{});
1636	}
1637
1638	if (const VarRegion *VR = dyn_cast<VarRegion>(Val: R)) {
1639	// FIXME: Here we actually perform an implicit conversion from the loaded
1640	// value to the variable type. What we should model is stores to variables
1641	// that blow past the extent of the variable. If the address of the
1642	// variable is reinterpretted, it is possible we stored a different value
1643	// that could fit within the variable. Either we need to cast these when
1644	// storing them or reinterpret them lazily (as we do here).
1645	return svalBuilder.evalCast(V: getBindingForVar(B, R: VR), CastTy: T, OriginalTy: QualType{});
1646	}
1647
1648	const SVal *V = B.lookup(R, k: BindingKey::Direct);
1649
1650	// Check if the region has a binding.
1651	if (V)
1652	return *V;
1653
1654	// The location does not have a bound value. This means that it has
1655	// the value it had upon its creation and/or entry to the analyzed
1656	// function/method. These are either symbolic values or 'undefined'.
1657	if (isa<StackLocalsSpaceRegion>(Val: R->getRawMemorySpace())) {
1658	// All stack variables are considered to have undefined values
1659	// upon creation. All heap allocated blocks are considered to
1660	// have undefined values as well unless they are explicitly bound
1661	// to specific values.
1662	return UndefinedVal();
1663	}
1664
1665	// All other values are symbolic.
1666	return svalBuilder.getRegionValueSymbolVal(region: R);
1667	}
1668
1669	static QualType getUnderlyingType(const SubRegion *R) {
1670	QualType RegionTy;
1671	if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(Val: R))
1672	RegionTy = TVR->getValueType();
1673
1674	if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Val: R))
1675	RegionTy = SR->getSymbol()->getType();
1676
1677	return RegionTy;
1678	}
1679
1680	/// Checks to see if store \p B has a lazy binding for region \p R.
1681	///
1682	/// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected
1683	/// if there are additional bindings within \p R.
1684	///
1685	/// Note that unlike RegionStoreManager::findLazyBinding, this will not search
1686	/// for lazy bindings for super-regions of \p R.
1687	static std::optional<nonloc::LazyCompoundVal>
1688	getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B,
1689	const SubRegion *R, bool AllowSubregionBindings) {
1690	std::optional<SVal> V = B.getDefaultBinding(R);
1691	if (!V)
1692	return std::nullopt;
1693
1694	std::optional<nonloc::LazyCompoundVal> LCV =
1695	V->getAs<nonloc::LazyCompoundVal>();
1696	if (!LCV)
1697	return std::nullopt;
1698
1699	// If the LCV is for a subregion, the types might not match, and we shouldn't
1700	// reuse the binding.
1701	QualType RegionTy = getUnderlyingType(R);
1702	if (!RegionTy.isNull() &&
1703	!RegionTy->isVoidPointerType()) {
1704	QualType SourceRegionTy = LCV->getRegion()->getValueType();
1705	if (!SVB.getContext().hasSameUnqualifiedType(T1: RegionTy, T2: SourceRegionTy))
1706	return std::nullopt;
1707	}
1708
1709	if (!AllowSubregionBindings) {
1710	// If there are any other bindings within this region, we shouldn't reuse
1711	// the top-level binding.
1712	SmallVector<BindingPair, 16> Bindings;
1713	collectSubRegionBindings(Bindings, SVB, Cluster: *B.lookup(K: R->getBaseRegion()), Top: R,
1714	/*IncludeAllDefaultBindings=*/true);
1715	if (Bindings.size() > 1)
1716	return std::nullopt;
1717	}
1718
1719	return *LCV;
1720	}
1721
1722	std::pair<Store, const SubRegion *>
1723	RegionStoreManager::findLazyBinding(RegionBindingsConstRef B,
1724	const SubRegion *R,
1725	const SubRegion *originalRegion) {
1726	if (originalRegion != R) {
1727	if (std::optional<nonloc::LazyCompoundVal> V =
1728	getExistingLazyBinding(SVB&: svalBuilder, B, R, AllowSubregionBindings: true))
1729	return std::make_pair(x: V->getStore(), y: V->getRegion());
1730	}
1731
1732	typedef std::pair<Store, const SubRegion *> StoreRegionPair;
1733	StoreRegionPair Result = StoreRegionPair();
1734
1735	if (const ElementRegion *ER = dyn_cast<ElementRegion>(Val: R)) {
1736	Result = findLazyBinding(B, R: cast<SubRegion>(ER->getSuperRegion()),
1737	originalRegion);
1738
1739	if (Result.second)
1740	Result.second = MRMgr.getElementRegionWithSuper(ER, superRegion: Result.second);
1741
1742	} else if (const FieldRegion *FR = dyn_cast<FieldRegion>(Val: R)) {
1743	Result = findLazyBinding(B, R: cast<SubRegion>(Val: FR->getSuperRegion()),
1744	originalRegion);
1745
1746	if (Result.second)
1747	Result.second = MRMgr.getFieldRegionWithSuper(FR, superRegion: Result.second);
1748
1749	} else if (const CXXBaseObjectRegion *BaseReg =
1750	dyn_cast<CXXBaseObjectRegion>(Val: R)) {
1751	// C++ base object region is another kind of region that we should blast
1752	// through to look for lazy compound value. It is like a field region.
1753	Result = findLazyBinding(B, R: cast<SubRegion>(Val: BaseReg->getSuperRegion()),
1754	originalRegion);
1755
1756	if (Result.second)
1757	Result.second = MRMgr.getCXXBaseObjectRegionWithSuper(baseReg: BaseReg,
1758	superRegion: Result.second);
1759	}
1760
1761	return Result;
1762	}
1763
1764	/// This is a helper function for `getConstantValFromConstArrayInitializer`.
1765	///
1766	/// Return an array of extents of the declared array type.
1767	///
1768	/// E.g. for `int x[1][2][3];` returns { 1, 2, 3 }.
1769	static SmallVector<uint64_t, 2>
1770	getConstantArrayExtents(const ConstantArrayType *CAT) {
1771	assert(CAT && "ConstantArrayType should not be null");
1772	CAT = cast<ConstantArrayType>(CAT->getCanonicalTypeInternal());
1773	SmallVector<uint64_t, 2> Extents;
1774	do {
1775	Extents.push_back(Elt: CAT->getZExtSize());
1776	} while ((CAT = dyn_cast<ConstantArrayType>(CAT->getElementType())));
1777	return Extents;
1778	}
1779
1780	/// This is a helper function for `getConstantValFromConstArrayInitializer`.
1781	///
1782	/// Return an array of offsets from nested ElementRegions and a root base
1783	/// region. The array is never empty and a base region is never null.
1784	///
1785	/// E.g. for `Element{Element{Element{VarRegion},1},2},3}` returns { 3, 2, 1 }.
1786	/// This represents an access through indirection: `arr[1][2][3];`
1787	///
1788	/// \param ER The given (possibly nested) ElementRegion.
1789	///
1790	/// \note The result array is in the reverse order of indirection expression:
1791	/// arr[1][2][3] -> { 3, 2, 1 }. This helps to provide complexity O(n), where n
1792	/// is a number of indirections. It may not affect performance in real-life
1793	/// code, though.
1794	static std::pair<SmallVector<SVal, 2>, const MemRegion *>
1795	getElementRegionOffsetsWithBase(const ElementRegion *ER) {
1796	assert(ER && "ConstantArrayType should not be null");
1797	const MemRegion *Base;
1798	SmallVector<SVal, 2> SValOffsets;
1799	do {
1800	SValOffsets.push_back(Elt: ER->getIndex());
1801	Base = ER->getSuperRegion();
1802	ER = dyn_cast<ElementRegion>(Val: Base);
1803	} while (ER);
1804	return {SValOffsets, Base};
1805	}
1806
1807	/// This is a helper function for `getConstantValFromConstArrayInitializer`.
1808	///
1809	/// Convert array of offsets from `SVal` to `uint64_t` in consideration of
1810	/// respective array extents.
1811	/// \param SrcOffsets [in] The array of offsets of type `SVal` in reversed
1812	/// order (expectedly received from `getElementRegionOffsetsWithBase`).
1813	/// \param ArrayExtents [in] The array of extents.
1814	/// \param DstOffsets [out] The array of offsets of type `uint64_t`.
1815	/// \returns:
1816	/// - `std::nullopt` for successful convertion.
1817	/// - `UndefinedVal` or `UnknownVal` otherwise. It's expected that this SVal
1818	/// will be returned as a suitable value of the access operation.
1819	/// which should be returned as a correct
1820	///
1821	/// \example:
1822	/// const int arr[10][20][30] = {}; // ArrayExtents { 10, 20, 30 }
1823	/// int x1 = arr[4][5][6]; // SrcOffsets { NonLoc(6), NonLoc(5), NonLoc(4) }
1824	/// // DstOffsets { 4, 5, 6 }
1825	/// // returns std::nullopt
1826	/// int x2 = arr[42][5][-6]; // returns UndefinedVal
1827	/// int x3 = arr[4][5][x2]; // returns UnknownVal
1828	static std::optional<SVal>
1829	convertOffsetsFromSvalToUnsigneds(const SmallVector<SVal, 2> &SrcOffsets,
1830	const SmallVector<uint64_t, 2> ArrayExtents,
1831	SmallVector<uint64_t, 2> &DstOffsets) {
1832	// Check offsets for being out of bounds.
1833	// C++20 [expr.add] 7.6.6.4 (excerpt):
1834	// If P points to an array element i of an array object x with n
1835	// elements, where i < 0 or i > n, the behavior is undefined.
1836	// Dereferencing is not allowed on the "one past the last
1837	// element", when i == n.
1838	// Example:
1839	// const int arr[3][2] = {{1, 2}, {3, 4}};
1840	// arr[0][0]; // 1
1841	// arr[0][1]; // 2
1842	// arr[0][2]; // UB
1843	// arr[1][0]; // 3
1844	// arr[1][1]; // 4
1845	// arr[1][-1]; // UB
1846	// arr[2][0]; // 0
1847	// arr[2][1]; // 0
1848	// arr[-2][0]; // UB
1849	DstOffsets.resize(N: SrcOffsets.size());
1850	auto ExtentIt = ArrayExtents.begin();
1851	auto OffsetIt = DstOffsets.begin();
1852	// Reverse `SValOffsets` to make it consistent with `ArrayExtents`.
1853	for (SVal V : llvm::reverse(C: SrcOffsets)) {
1854	if (auto CI = V.getAs<nonloc::ConcreteInt>()) {
1855	// When offset is out of array's bounds, result is UB.
1856	const llvm::APSInt &Offset = CI->getValue();
1857	if (Offset.isNegative() || Offset.uge(RHS: *(ExtentIt++)))
1858	return UndefinedVal();
1859	// Store index in a reversive order.
1860	*(OffsetIt++) = Offset.getZExtValue();
1861	continue;
1862	}
1863	// Symbolic index presented. Return Unknown value.
1864	// FIXME: We also need to take ElementRegions with symbolic indexes into
1865	// account.
1866	return UnknownVal();
1867	}
1868	return std::nullopt;
1869	}
1870
1871	std::optional<SVal> RegionStoreManager::getConstantValFromConstArrayInitializer(
1872	RegionBindingsConstRef B, const ElementRegion *R) {
1873	assert(R && "ElementRegion should not be null");
1874
1875	// Treat an n-dimensional array.
1876	SmallVector<SVal, 2> SValOffsets;
1877	const MemRegion *Base;
1878	std::tie(args&: SValOffsets, args&: Base) = getElementRegionOffsetsWithBase(ER: R);
1879	const VarRegion *VR = dyn_cast<VarRegion>(Val: Base);
1880	if (!VR)
1881	return std::nullopt;
1882
1883	assert(!SValOffsets.empty() && "getElementRegionOffsets guarantees the "
1884	"offsets vector is not empty.");
1885
1886	// Check if the containing array has an initialized value that we can trust.
1887	// We can trust a const value or a value of a global initializer in main().
1888	const VarDecl *VD = VR->getDecl();
1889	if (!VD->getType().isConstQualified() &&
1890	!R->getElementType().isConstQualified() &&
1891	(!B.isMainAnalysis() || !VD->hasGlobalStorage()))
1892	return std::nullopt;
1893
1894	// Array's declaration should have `ConstantArrayType` type, because only this
1895	// type contains an array extent. It may happen that array type can be of
1896	// `IncompleteArrayType` type. To get the declaration of `ConstantArrayType`
1897	// type, we should find the declaration in the redeclarations chain that has
1898	// the initialization expression.
1899	// NOTE: `getAnyInitializer` has an out-parameter, which returns a new `VD`
1900	// from which an initializer is obtained. We replace current `VD` with the new
1901	// `VD`. If the return value of the function is null than `VD` won't be
1902	// replaced.
1903	const Expr *Init = VD->getAnyInitializer(D&: VD);
1904	// NOTE: If `Init` is non-null, then a new `VD` is non-null for sure. So check
1905	// `Init` for null only and don't worry about the replaced `VD`.
1906	if (!Init)
1907	return std::nullopt;
1908
1909	// Array's declaration should have ConstantArrayType type, because only this
1910	// type contains an array extent.
1911	const ConstantArrayType *CAT = Ctx.getAsConstantArrayType(T: VD->getType());
1912	if (!CAT)
1913	return std::nullopt;
1914
1915	// Get array extents.
1916	SmallVector<uint64_t, 2> Extents = getConstantArrayExtents(CAT);
1917
1918	// The number of offsets should equal to the numbers of extents,
1919	// otherwise wrong type punning occurred. For instance:
1920	// int arr[1][2][3];
1921	// auto ptr = (int(*)[42])arr;
1922	// auto x = ptr[4][2]; // UB
1923	// FIXME: Should return UndefinedVal.
1924	if (SValOffsets.size() != Extents.size())
1925	return std::nullopt;
1926
1927	SmallVector<uint64_t, 2> ConcreteOffsets;
1928	if (std::optional<SVal> V = convertOffsetsFromSvalToUnsigneds(
1929	SrcOffsets: SValOffsets, ArrayExtents: Extents, DstOffsets&: ConcreteOffsets))
1930	return *V;
1931
1932	// Handle InitListExpr.
1933	// Example:
1934	// const char arr[4][2] = { { 1, 2 }, { 3 }, 4, 5 };
1935	if (const auto *ILE = dyn_cast<InitListExpr>(Val: Init))
1936	return getSValFromInitListExpr(ILE, ConcreteOffsets, ElemT: R->getElementType());
1937
1938	// Handle StringLiteral.
1939	// Example:
1940	// const char arr[] = "abc";
1941	if (const auto *SL = dyn_cast<StringLiteral>(Val: Init))
1942	return getSValFromStringLiteral(SL, Offset: ConcreteOffsets.front(),
1943	ElemT: R->getElementType());
1944
1945	// FIXME: Handle CompoundLiteralExpr.
1946
1947	return std::nullopt;
1948	}
1949
1950	/// Returns an SVal, if possible, for the specified position of an
1951	/// initialization list.
1952	///
1953	/// \param ILE The given initialization list.
1954	/// \param Offsets The array of unsigned offsets. E.g. for the expression
1955	/// `int x = arr[1][2][3];` an array should be { 1, 2, 3 }.
1956	/// \param ElemT The type of the result SVal expression.
1957	/// \return Optional SVal for the particular position in the initialization
1958	/// list. E.g. for the list `{{1, 2},[3, 4],{5, 6}, {}}` offsets:
1959	/// - {1, 1} returns SVal{4}, because it's the second position in the second
1960	/// sublist;
1961	/// - {3, 0} returns SVal{0}, because there's no explicit value at this
1962	/// position in the sublist.
1963	///
1964	/// NOTE: Inorder to get a valid SVal, a caller shall guarantee valid offsets
1965	/// for the given initialization list. Otherwise SVal can be an equivalent to 0
1966	/// or lead to assertion.
1967	std::optional<SVal> RegionStoreManager::getSValFromInitListExpr(
1968	const InitListExpr *ILE, const SmallVector<uint64_t, 2> &Offsets,
1969	QualType ElemT) {
1970	assert(ILE && "InitListExpr should not be null");
1971
1972	for (uint64_t Offset : Offsets) {
1973	// C++20 [dcl.init.string] 9.4.2.1:
1974	// An array of ordinary character type [...] can be initialized by [...]
1975	// an appropriately-typed string-literal enclosed in braces.
1976	// Example:
1977	// const char arr[] = { "abc" };
1978	if (ILE->isStringLiteralInit())
1979	if (const auto *SL = dyn_cast<StringLiteral>(Val: ILE->getInit(Init: 0)))
1980	return getSValFromStringLiteral(SL, Offset, ElemT);
1981
1982	// C++20 [expr.add] 9.4.17.5 (excerpt):
1983	// i-th array element is value-initialized for each k < i ≤ n,
1984	// where k is an expression-list size and n is an array extent.
1985	if (Offset >= ILE->getNumInits())
1986	return svalBuilder.makeZeroVal(type: ElemT);
1987
1988	const Expr *E = ILE->getInit(Init: Offset);
1989	const auto *IL = dyn_cast<InitListExpr>(Val: E);
1990	if (!IL)
1991	// Return a constant value, if it is presented.
1992	// FIXME: Support other SVals.
1993	return svalBuilder.getConstantVal(E);
1994
1995	// Go to the nested initializer list.
1996	ILE = IL;
1997	}
1998
1999	assert(ILE);
2000
2001	// FIXME: Unhandeled InitListExpr sub-expression, possibly constructing an
2002	// enum?
2003	return std::nullopt;
2004	}
2005
2006	/// Returns an SVal, if possible, for the specified position in a string
2007	/// literal.
2008	///
2009	/// \param SL The given string literal.
2010	/// \param Offset The unsigned offset. E.g. for the expression
2011	/// `char x = str[42];` an offset should be 42.
2012	/// E.g. for the string "abc" offset:
2013	/// - 1 returns SVal{b}, because it's the second position in the string.
2014	/// - 42 returns SVal{0}, because there's no explicit value at this
2015	/// position in the string.
2016	/// \param ElemT The type of the result SVal expression.
2017	///
2018	/// NOTE: We return `0` for every offset >= the literal length for array
2019	/// declarations, like:
2020	/// const char str[42] = "123"; // Literal length is 4.
2021	/// char c = str[41]; // Offset is 41.
2022	/// FIXME: Nevertheless, we can't do the same for pointer declaraions, like:
2023	/// const char * const str = "123"; // Literal length is 4.
2024	/// char c = str[41]; // Offset is 41. Returns `0`, but Undef
2025	/// // expected.
2026	/// It should be properly handled before reaching this point.
2027	/// The main problem is that we can't distinguish between these declarations,
2028	/// because in case of array we can get the Decl from VarRegion, but in case
2029	/// of pointer the region is a StringRegion, which doesn't contain a Decl.
2030	/// Possible solution could be passing an array extent along with the offset.
2031	SVal RegionStoreManager::getSValFromStringLiteral(const StringLiteral *SL,
2032	uint64_t Offset,
2033	QualType ElemT) {
2034	assert(SL && "StringLiteral should not be null");
2035	// C++20 [dcl.init.string] 9.4.2.3:
2036	// If there are fewer initializers than there are array elements, each
2037	// element not explicitly initialized shall be zero-initialized [dcl.init].
2038	uint32_t Code = (Offset >= SL->getLength()) ? 0 : SL->getCodeUnit(i: Offset);
2039	return svalBuilder.makeIntVal(integer: Code, type: ElemT);
2040	}
2041
2042	static std::optional<SVal> getDerivedSymbolForBinding(
2043	RegionBindingsConstRef B, const TypedValueRegion *BaseRegion,
2044	const TypedValueRegion *SubReg, const ASTContext &Ctx, SValBuilder &SVB) {
2045	assert(BaseRegion);
2046	QualType BaseTy = BaseRegion->getValueType();
2047	QualType Ty = SubReg->getValueType();
2048	if (BaseTy->isScalarType() && Ty->isScalarType()) {
2049	if (Ctx.getTypeSizeInChars(T: BaseTy) >= Ctx.getTypeSizeInChars(T: Ty)) {
2050	if (const std::optional<SVal> &ParentValue =
2051	B.getDirectBinding(R: BaseRegion)) {
2052	if (SymbolRef ParentValueAsSym = ParentValue->getAsSymbol())
2053	return SVB.getDerivedRegionValueSymbolVal(parentSymbol: ParentValueAsSym, region: SubReg);
2054
2055	if (ParentValue->isUndef())
2056	return UndefinedVal();
2057
2058	// Other cases: give up. We are indexing into a larger object
2059	// that has some value, but we don't know how to handle that yet.
2060	return UnknownVal();
2061	}
2062	}
2063	}
2064	return std::nullopt;
2065	}
2066
2067	SVal RegionStoreManager::getBindingForElement(RegionBindingsConstRef B,
2068	const ElementRegion* R) {
2069	// Check if the region has a binding.
2070	if (const std::optional<SVal> &V = B.getDirectBinding(R))
2071	return *V;
2072
2073	const MemRegion* superR = R->getSuperRegion();
2074
2075	// Check if the region is an element region of a string literal.
2076	if (const StringRegion *StrR = dyn_cast<StringRegion>(Val: superR)) {
2077	// FIXME: Handle loads from strings where the literal is treated as
2078	// an integer, e.g., *((unsigned int*)"hello"). Such loads are UB according
2079	// to C++20 7.2.1.11 [basic.lval].
2080	QualType T = Ctx.getAsArrayType(T: StrR->getValueType())->getElementType();
2081	if (!Ctx.hasSameUnqualifiedType(T1: T, T2: R->getElementType()))
2082	return UnknownVal();
2083	if (const auto CI = R->getIndex().getAs<nonloc::ConcreteInt>()) {
2084	const llvm::APSInt &Idx = CI->getValue();
2085	if (Idx < 0)
2086	return UndefinedVal();
2087	const StringLiteral *SL = StrR->getStringLiteral();
2088	return getSValFromStringLiteral(SL, Offset: Idx.getZExtValue(), ElemT: T);
2089	}
2090	} else if (isa<ElementRegion, VarRegion>(Val: superR)) {
2091	if (std::optional<SVal> V = getConstantValFromConstArrayInitializer(B, R))
2092	return *V;
2093	}
2094
2095	// Check for loads from a code text region. For such loads, just give up.
2096	if (isa<CodeTextRegion>(Val: superR))
2097	return UnknownVal();
2098
2099	// Handle the case where we are indexing into a larger scalar object.
2100	// For example, this handles:
2101	// int x = ...
2102	// char *y = &x;
2103	// return *y;
2104	// FIXME: This is a hack, and doesn't do anything really intelligent yet.
2105	const RegionRawOffset &O = R->getAsArrayOffset();
2106
2107	// If we cannot reason about the offset, return an unknown value.
2108	if (!O.getRegion())
2109	return UnknownVal();
2110
2111	if (const TypedValueRegion *baseR = dyn_cast<TypedValueRegion>(Val: O.getRegion()))
2112	if (auto V = getDerivedSymbolForBinding(B, baseR, R, Ctx, svalBuilder))
2113	return *V;
2114
2115	return getBindingForFieldOrElementCommon(B, R, R->getElementType());
2116	}
2117
2118	SVal RegionStoreManager::getBindingForField(RegionBindingsConstRef B,
2119	const FieldRegion* R) {
2120
2121	// Check if the region has a binding.
2122	if (const std::optional<SVal> &V = B.getDirectBinding(R))
2123	return *V;
2124
2125	// If the containing record was initialized, try to get its constant value.
2126	const FieldDecl *FD = R->getDecl();
2127	QualType Ty = FD->getType();
2128	const MemRegion* superR = R->getSuperRegion();
2129	if (const auto *VR = dyn_cast<VarRegion>(Val: superR)) {
2130	const VarDecl *VD = VR->getDecl();
2131	QualType RecordVarTy = VD->getType();
2132	unsigned Index = FD->getFieldIndex();
2133	// Either the record variable or the field has an initializer that we can
2134	// trust. We trust initializers of constants and, additionally, respect
2135	// initializers of globals when analyzing main().
2136	if (RecordVarTy.isConstQualified() || Ty.isConstQualified() ||
2137	(B.isMainAnalysis() && VD->hasGlobalStorage()))
2138	if (const Expr *Init = VD->getAnyInitializer())
2139	if (const auto *InitList = dyn_cast<InitListExpr>(Val: Init)) {
2140	if (Index < InitList->getNumInits()) {
2141	if (const Expr *FieldInit = InitList->getInit(Init: Index))
2142	if (std::optional<SVal> V = svalBuilder.getConstantVal(E: FieldInit))
2143	return *V;
2144	} else {
2145	return svalBuilder.makeZeroVal(type: Ty);
2146	}
2147	}
2148	}
2149
2150	// Handle the case where we are accessing into a larger scalar object.
2151	// For example, this handles:
2152	// struct header {
2153	// unsigned a : 1;
2154	// unsigned b : 1;
2155	// };
2156	// struct parse_t {
2157	// unsigned bits0 : 1;
2158	// unsigned bits2 : 2; // <-- header
2159	// unsigned bits4 : 4;
2160	// };
2161	// int parse(parse_t *p) {
2162	// unsigned copy = p->bits2;
2163	// header *bits = (header *)&copy;
2164	// return bits->b; <-- here
2165	// }
2166	if (const auto *Base = dyn_cast<TypedValueRegion>(Val: R->getBaseRegion()))
2167	if (auto V = getDerivedSymbolForBinding(B, BaseRegion: Base, SubReg: R, Ctx, SVB&: svalBuilder))
2168	return *V;
2169
2170	return getBindingForFieldOrElementCommon(B, R, Ty);
2171	}
2172
2173	std::optional<SVal> RegionStoreManager::getBindingForDerivedDefaultValue(
2174	RegionBindingsConstRef B, const MemRegion *superR,
2175	const TypedValueRegion *R, QualType Ty) {
2176
2177	if (const std::optional<SVal> &D = B.getDefaultBinding(R: superR)) {
2178	SVal val = *D;
2179	if (SymbolRef parentSym = val.getAsSymbol())
2180	return svalBuilder.getDerivedRegionValueSymbolVal(parentSymbol: parentSym, region: R);
2181
2182	if (val.isZeroConstant())
2183	return svalBuilder.makeZeroVal(type: Ty);
2184
2185	if (val.isUnknownOrUndef())
2186	return val;
2187
2188	// Lazy bindings are usually handled through getExistingLazyBinding().
2189	// We should unify these two code paths at some point.
2190	if (isa<nonloc::LazyCompoundVal, nonloc::CompoundVal>(Val: val))
2191	return val;
2192
2193	llvm_unreachable("Unknown default value");
2194	}
2195
2196	return std::nullopt;
2197	}
2198
2199	SVal RegionStoreManager::getLazyBinding(const SubRegion *LazyBindingRegion,
2200	RegionBindingsRef LazyBinding) {
2201	SVal Result;
2202	if (const ElementRegion *ER = dyn_cast<ElementRegion>(Val: LazyBindingRegion))
2203	Result = getBindingForElement(B: LazyBinding, R: ER);
2204	else
2205	Result = getBindingForField(B: LazyBinding,
2206	R: cast<FieldRegion>(Val: LazyBindingRegion));
2207
2208	// FIXME: This is a hack to deal with RegionStore's inability to distinguish a
2209	// default value for /part/ of an aggregate from a default value for the
2210	// /entire/ aggregate. The most common case of this is when struct Outer
2211	// has as its first member a struct Inner, which is copied in from a stack
2212	// variable. In this case, even if the Outer's default value is symbolic, 0,
2213	// or unknown, it gets overridden by the Inner's default value of undefined.
2214	//
2215	// This is a general problem -- if the Inner is zero-initialized, the Outer
2216	// will now look zero-initialized. The proper way to solve this is with a
2217	// new version of RegionStore that tracks the extent of a binding as well
2218	// as the offset.
2219	//
2220	// This hack only takes care of the undefined case because that can very
2221	// quickly result in a warning.
2222	if (Result.isUndef())
2223	Result = UnknownVal();
2224
2225	return Result;
2226	}
2227
2228	SVal
2229	RegionStoreManager::getBindingForFieldOrElementCommon(RegionBindingsConstRef B,
2230	const TypedValueRegion *R,
2231	QualType Ty) {
2232
2233	// At this point we have already checked in either getBindingForElement or
2234	// getBindingForField if 'R' has a direct binding.
2235
2236	// Lazy binding?
2237	Store lazyBindingStore = nullptr;
2238	const SubRegion *lazyBindingRegion = nullptr;
2239	std::tie(args&: lazyBindingStore, args&: lazyBindingRegion) = findLazyBinding(B, R, originalRegion: R);
2240	if (lazyBindingRegion)
2241	return getLazyBinding(LazyBindingRegion: lazyBindingRegion,
2242	LazyBinding: getRegionBindings(store: lazyBindingStore));
2243
2244	// Record whether or not we see a symbolic index. That can completely
2245	// be out of scope of our lookup.
2246	bool hasSymbolicIndex = false;
2247
2248	// FIXME: This is a hack to deal with RegionStore's inability to distinguish a
2249	// default value for /part/ of an aggregate from a default value for the
2250	// /entire/ aggregate. The most common case of this is when struct Outer
2251	// has as its first member a struct Inner, which is copied in from a stack
2252	// variable. In this case, even if the Outer's default value is symbolic, 0,
2253	// or unknown, it gets overridden by the Inner's default value of undefined.
2254	//
2255	// This is a general problem -- if the Inner is zero-initialized, the Outer
2256	// will now look zero-initialized. The proper way to solve this is with a
2257	// new version of RegionStore that tracks the extent of a binding as well
2258	// as the offset.
2259	//
2260	// This hack only takes care of the undefined case because that can very
2261	// quickly result in a warning.
2262	bool hasPartialLazyBinding = false;
2263
2264	const SubRegion *SR = R;
2265	while (SR) {
2266	const MemRegion *Base = SR->getSuperRegion();
2267	if (std::optional<SVal> D =
2268	getBindingForDerivedDefaultValue(B, superR: Base, R, Ty)) {
2269	if (D->getAs<nonloc::LazyCompoundVal>()) {
2270	hasPartialLazyBinding = true;
2271	break;
2272	}
2273
2274	return *D;
2275	}
2276
2277	if (const ElementRegion *ER = dyn_cast<ElementRegion>(Val: Base)) {
2278	NonLoc index = ER->getIndex();
2279	if (!index.isConstant())
2280	hasSymbolicIndex = true;
2281	}
2282
2283	// If our super region is a field or element itself, walk up the region
2284	// hierarchy to see if there is a default value installed in an ancestor.
2285	SR = dyn_cast<SubRegion>(Val: Base);
2286	}
2287
2288	if (isa<StackLocalsSpaceRegion>(Val: R->getRawMemorySpace())) {
2289	if (isa<ElementRegion>(Val: R)) {
2290	// Currently we don't reason specially about Clang-style vectors. Check
2291	// if superR is a vector and if so return Unknown.
2292	if (const TypedValueRegion *typedSuperR =
2293	dyn_cast<TypedValueRegion>(Val: R->getSuperRegion())) {
2294	if (typedSuperR->getValueType()->isVectorType())
2295	return UnknownVal();
2296	}
2297	}
2298
2299	// FIXME: We also need to take ElementRegions with symbolic indexes into
2300	// account. This case handles both directly accessing an ElementRegion
2301	// with a symbolic offset, but also fields within an element with
2302	// a symbolic offset.
2303	if (hasSymbolicIndex)
2304	return UnknownVal();
2305
2306	// Additionally allow introspection of a block's internal layout.
2307	// Try to get direct binding if all other attempts failed thus far.
2308	// Else, return UndefinedVal()
2309	if (!hasPartialLazyBinding && !isa<BlockDataRegion>(Val: R->getBaseRegion())) {
2310	if (const std::optional<SVal> &V = B.getDefaultBinding(R))
2311	return *V;
2312	return UndefinedVal();
2313	}
2314	}
2315
2316	// All other values are symbolic.
2317	return svalBuilder.getRegionValueSymbolVal(region: R);
2318	}
2319
2320	SVal RegionStoreManager::getBindingForObjCIvar(RegionBindingsConstRef B,
2321	const ObjCIvarRegion* R) {
2322	// Check if the region has a binding.
2323	if (const std::optional<SVal> &V = B.getDirectBinding(R))
2324	return *V;
2325
2326	const MemRegion *superR = R->getSuperRegion();
2327
2328	// Check if the super region has a default binding.
2329	if (const std::optional<SVal> &V = B.getDefaultBinding(R: superR)) {
2330	if (SymbolRef parentSym = V->getAsSymbol())
2331	return svalBuilder.getDerivedRegionValueSymbolVal(parentSymbol: parentSym, region: R);
2332
2333	// Other cases: give up.
2334	return UnknownVal();
2335	}
2336
2337	return getBindingForLazySymbol(R);
2338	}
2339
2340	SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B,
2341	const VarRegion *R) {
2342
2343	// Check if the region has a binding.
2344	if (std::optional<SVal> V = B.getDirectBinding(R))
2345	return *V;
2346
2347	if (std::optional<SVal> V = B.getDefaultBinding(R))
2348	return *V;
2349
2350	// Lazily derive a value for the VarRegion.
2351	const VarDecl *VD = R->getDecl();
2352	const MemSpaceRegion *MS = R->getRawMemorySpace();
2353
2354	// Arguments are always symbolic.
2355	if (isa<StackArgumentsSpaceRegion>(Val: MS))
2356	return svalBuilder.getRegionValueSymbolVal(region: R);
2357
2358	// Is 'VD' declared constant? If so, retrieve the constant value.
2359	if (VD->getType().isConstQualified()) {
2360	if (const Expr *Init = VD->getAnyInitializer()) {
2361	if (std::optional<SVal> V = svalBuilder.getConstantVal(E: Init))
2362	return *V;
2363
2364	// If the variable is const qualified and has an initializer but
2365	// we couldn't evaluate initializer to a value, treat the value as
2366	// unknown.
2367	return UnknownVal();
2368	}
2369	}
2370
2371	// This must come after the check for constants because closure-captured
2372	// constant variables may appear in UnknownSpaceRegion.
2373	if (isa<UnknownSpaceRegion>(Val: MS))
2374	return svalBuilder.getRegionValueSymbolVal(region: R);
2375
2376	if (isa<GlobalsSpaceRegion>(Val: MS)) {
2377	QualType T = VD->getType();
2378
2379	// If we're in main(), then global initializers have not become stale yet.
2380	if (B.isMainAnalysis())
2381	if (const Expr *Init = VD->getAnyInitializer())
2382	if (std::optional<SVal> V = svalBuilder.getConstantVal(E: Init))
2383	return *V;
2384
2385	// Function-scoped static variables are default-initialized to 0; if they
2386	// have an initializer, it would have been processed by now.
2387	// FIXME: This is only true when we're starting analysis from main().
2388	// We're losing a lot of coverage here.
2389	if (isa<StaticGlobalSpaceRegion>(Val: MS))
2390	return svalBuilder.makeZeroVal(type: T);
2391
2392	if (std::optional<SVal> V = getBindingForDerivedDefaultValue(B, superR: MS, R, Ty: T)) {
2393	assert(!V->getAs<nonloc::LazyCompoundVal>());
2394	return *V;
2395	}
2396
2397	return svalBuilder.getRegionValueSymbolVal(region: R);
2398	}
2399
2400	return UndefinedVal();
2401	}
2402
2403	SVal RegionStoreManager::getBindingForLazySymbol(const TypedValueRegion *R) {
2404	// All other values are symbolic.
2405	return svalBuilder.getRegionValueSymbolVal(region: R);
2406	}
2407
2408	const RegionStoreManager::SValListTy &
2409	RegionStoreManager::getInterestingValues(nonloc::LazyCompoundVal LCV) {
2410	// First, check the cache.
2411	LazyBindingsMapTy::iterator I = LazyBindingsMap.find(Val: LCV.getCVData());
2412	if (I != LazyBindingsMap.end())
2413	return I->second;
2414
2415	// If we don't have a list of values cached, start constructing it.
2416	SValListTy List;
2417
2418	const SubRegion *LazyR = LCV.getRegion();
2419	RegionBindingsRef B = getRegionBindings(store: LCV.getStore());
2420
2421	// If this region had /no/ bindings at the time, there are no interesting
2422	// values to return.
2423	const ClusterBindings *Cluster = B.lookup(K: LazyR->getBaseRegion());
2424	if (!Cluster)
2425	return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2426
2427	SmallVector<BindingPair, 32> Bindings;
2428	collectSubRegionBindings(Bindings, SVB&: svalBuilder, Cluster: *Cluster, Top: LazyR,
2429	/*IncludeAllDefaultBindings=*/true);
2430	for (SVal V : llvm::make_second_range(c&: Bindings)) {
2431	if (V.isUnknownOrUndef() || V.isConstant())
2432	continue;
2433
2434	if (auto InnerLCV = V.getAs<nonloc::LazyCompoundVal>()) {
2435	const SValListTy &InnerList = getInterestingValues(LCV: *InnerLCV);
2436	llvm::append_range(C&: List, R: InnerList);
2437	}
2438
2439	List.push_back(x: V);
2440	}
2441
2442	return (LazyBindingsMap[LCV.getCVData()] = std::move(List));
2443	}
2444
2445	NonLoc RegionStoreManager::createLazyBinding(RegionBindingsConstRef B,
2446	const TypedValueRegion *R) {
2447	if (std::optional<nonloc::LazyCompoundVal> V =
2448	getExistingLazyBinding(SVB&: svalBuilder, B, R, AllowSubregionBindings: false))
2449	return *V;
2450
2451	return svalBuilder.makeLazyCompoundVal(store: StoreRef(B.asStore(), *this), region: R);
2452	}
2453
2454	SVal RegionStoreManager::getBindingForStruct(RegionBindingsConstRef B,
2455	const TypedValueRegion *R) {
2456	const RecordDecl *RD = R->getValueType()->castAs<RecordType>()->getDecl();
2457	if (!RD->getDefinition())
2458	return UnknownVal();
2459
2460	// We also create a LCV for copying empty structs because then the store
2461	// behavior doesn't depend on the struct layout.
2462	// This way even an empty struct can carry taint, no matter if creduce drops
2463	// the last field member or not.
2464
2465	// Try to avoid creating a LCV if it would anyways just refer to a single
2466	// default binding.
2467	if (std::optional<SVal> Val = getUniqueDefaultBinding(B, R))
2468	return *Val;
2469	return createLazyBinding(B, R);
2470	}
2471
2472	SVal RegionStoreManager::getBindingForArray(RegionBindingsConstRef B,
2473	const TypedValueRegion *R) {
2474	assert(Ctx.getAsConstantArrayType(R->getValueType()) &&
2475	"Only constant array types can have compound bindings.");
2476
2477	return createLazyBinding(B, R);
2478	}
2479
2480	bool RegionStoreManager::includedInBindings(Store store,
2481	const MemRegion *region) const {
2482	RegionBindingsRef B = getRegionBindings(store);
2483	region = region->getBaseRegion();
2484
2485	// Quick path: if the base is the head of a cluster, the region is live.
2486	if (B.lookup(K: region))
2487	return true;
2488
2489	// Slow path: if the region is the VALUE of any binding, it is live.
2490	for (RegionBindingsRef::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) {
2491	const ClusterBindings &Cluster = RI.getData();
2492	for (ClusterBindings::iterator CI = Cluster.begin(), CE = Cluster.end();
2493	CI != CE; ++CI) {
2494	SVal D = CI.getData();
2495	if (const MemRegion *R = D.getAsRegion())
2496	if (R->getBaseRegion() == region)
2497	return true;
2498	}
2499	}
2500
2501	return false;
2502	}
2503
2504	//===----------------------------------------------------------------------===//
2505	// Binding values to regions.
2506	//===----------------------------------------------------------------------===//
2507
2508	StoreRef RegionStoreManager::killBinding(Store ST, Loc L) {
2509	if (std::optional<loc::MemRegionVal> LV = L.getAs<loc::MemRegionVal>())
2510	if (const MemRegion* R = LV->getRegion())
2511	return StoreRef(getRegionBindings(store: ST)
2512	.removeBinding(R)
2513	.asImmutableMap()
2514	.getRootWithoutRetain(),
2515	*this);
2516
2517	return StoreRef(ST, *this);
2518	}
2519
2520	LimitedRegionBindingsRef
2521	RegionStoreManager::bind(LimitedRegionBindingsConstRef B, Loc L, SVal V) {
2522	llvm::TimeTraceScope TimeScope("RegionStoreManager::bind",
2523	[&L]() { return locDescr(L); });
2524
2525	if (B.hasExhaustedBindingLimit())
2526	return B.withValuesEscaped(V);
2527
2528	// We only care about region locations.
2529	auto MemRegVal = L.getAs<loc::MemRegionVal>();
2530	if (!MemRegVal)
2531	return B;
2532
2533	const MemRegion *R = MemRegVal->getRegion();
2534
2535	// Binding directly to a symbolic region should be treated as binding
2536	// to element 0.
2537	if (const auto *SymReg = dyn_cast<SymbolicRegion>(Val: R)) {
2538	QualType Ty = SymReg->getPointeeStaticType();
2539	if (Ty->isVoidType())
2540	Ty = StateMgr.getContext().CharTy;
2541	R = GetElementZeroRegion(R: SymReg, T: Ty);
2542	}
2543
2544	// Check if the region is a struct region.
2545	if (const TypedValueRegion* TR = dyn_cast<TypedValueRegion>(Val: R)) {
2546	QualType Ty = TR->getValueType();
2547	if (Ty->isArrayType())
2548	return bindArray(B, R: TR, V);
2549	if (Ty->isStructureOrClassType())
2550	return bindStruct(B, R: TR, V);
2551	if (Ty->isVectorType())
2552	return bindVector(B, R: TR, V);
2553	if (Ty->isUnionType())
2554	return bindAggregate(B, R: TR, DefaultVal: V);
2555	}
2556
2557	assert((!isa<CXXThisRegion>(R) || !B.lookup(R)) &&
2558	"'this' pointer is not an l-value and is not assignable");
2559
2560	// Clear out bindings that may overlap with this binding.
2561	auto NewB = removeSubRegionBindings(B, Top: cast<SubRegion>(Val: R));
2562
2563	// LazyCompoundVals should be always bound as 'default' bindings.
2564	auto KeyKind = isa<nonloc::LazyCompoundVal>(Val: V) ? BindingKey::Default
2565	: BindingKey::Direct;
2566	return NewB.addBinding(K: BindingKey::Make(R, k: KeyKind), V);
2567	}
2568
2569	LimitedRegionBindingsRef
2570	RegionStoreManager::setImplicitDefaultValue(LimitedRegionBindingsConstRef B,
2571	const MemRegion *R, QualType T) {
2572	if (B.hasExhaustedBindingLimit())
2573	return B;
2574
2575	SVal V;
2576
2577	if (Loc::isLocType(T))
2578	V = svalBuilder.makeNullWithType(type: T);
2579	else if (T->isIntegralOrEnumerationType())
2580	V = svalBuilder.makeZeroVal(type: T);
2581	else if (T->isStructureOrClassType() || T->isArrayType()) {
2582	// Set the default value to a zero constant when it is a structure
2583	// or array. The type doesn't really matter.
2584	V = svalBuilder.makeZeroVal(type: Ctx.IntTy);
2585	}
2586	else {
2587	// We can't represent values of this type, but we still need to set a value
2588	// to record that the region has been initialized.
2589	// If this assertion ever fires, a new case should be added above -- we
2590	// should know how to default-initialize any value we can symbolicate.
2591	assert(!SymbolManager::canSymbolicate(T) && "This type is representable");
2592	V = UnknownVal();
2593	}
2594
2595	return B.addBinding(R, k: BindingKey::Default, V);
2596	}
2597
2598	std::optional<LimitedRegionBindingsRef> RegionStoreManager::tryBindSmallArray(
2599	LimitedRegionBindingsConstRef B, const TypedValueRegion *R,
2600	const ArrayType *AT, nonloc::LazyCompoundVal LCV) {
2601	if (B.hasExhaustedBindingLimit())
2602	return B.withValuesEscaped(V: LCV);
2603
2604	auto CAT = dyn_cast<ConstantArrayType>(Val: AT);
2605
2606	// If we don't know the size, create a lazyCompoundVal instead.
2607	if (!CAT)
2608	return std::nullopt;
2609
2610	QualType Ty = CAT->getElementType();
2611	if (!(Ty->isScalarType() || Ty->isReferenceType()))
2612	return std::nullopt;
2613
2614	// If the array is too big, create a LCV instead.
2615	uint64_t ArrSize = CAT->getLimitedSize();
2616	if (ArrSize > SmallArrayLimit)
2617	return std::nullopt;
2618
2619	LimitedRegionBindingsRef NewB = B;
2620
2621	for (uint64_t i = 0; i < ArrSize; ++i) {
2622	auto Idx = svalBuilder.makeArrayIndex(idx: i);
2623	const ElementRegion *SrcER =
2624	MRMgr.getElementRegion(elementType: Ty, Idx, superRegion: LCV.getRegion(), Ctx);
2625	SVal V = getBindingForElement(B: getRegionBindings(store: LCV.getStore()), R: SrcER);
2626
2627	const ElementRegion *DstER = MRMgr.getElementRegion(elementType: Ty, Idx, superRegion: R, Ctx);
2628	NewB = bind(B: NewB, L: loc::MemRegionVal(DstER), V);
2629	}
2630
2631	return NewB;
2632	}
2633
2634	LimitedRegionBindingsRef
2635	RegionStoreManager::bindArray(LimitedRegionBindingsConstRef B,
2636	const TypedValueRegion *R, SVal Init) {
2637	llvm::TimeTraceScope TimeScope("RegionStoreManager::bindArray",
2638	[R]() { return R->getDescriptiveName(); });
2639	if (B.hasExhaustedBindingLimit())
2640	return B.withValuesEscaped(V: Init);
2641
2642	const ArrayType *AT =cast<ArrayType>(Val: Ctx.getCanonicalType(T: R->getValueType()));
2643	QualType ElementTy = AT->getElementType();
2644	std::optional<uint64_t> Size;
2645
2646	if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(Val: AT))
2647	Size = CAT->getZExtSize();
2648
2649	// Check if the init expr is a literal. If so, bind the rvalue instead.
2650	// FIXME: It's not responsibility of the Store to transform this lvalue
2651	// to rvalue. ExprEngine or maybe even CFG should do this before binding.
2652	if (std::optional<loc::MemRegionVal> MRV = Init.getAs<loc::MemRegionVal>()) {
2653	SVal V = getBinding(S: B.asStore(), L: *MRV, T: R->getValueType());
2654	return bindAggregate(B, R, DefaultVal: V);
2655	}
2656
2657	// Handle lazy compound values.
2658	if (std::optional LCV = Init.getAs<nonloc::LazyCompoundVal>()) {
2659	if (std::optional NewB = tryBindSmallArray(B, R, AT, LCV: *LCV))
2660	return *NewB;
2661
2662	return bindAggregate(B, R, DefaultVal: Init);
2663	}
2664
2665	if (Init.isUnknown())
2666	return bindAggregate(B, R, DefaultVal: UnknownVal());
2667
2668	// Remaining case: explicit compound values.
2669	const nonloc::CompoundVal& CV = Init.castAs<nonloc::CompoundVal>();
2670	nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2671	uint64_t i = 0;
2672
2673	LimitedRegionBindingsRef NewB = B;
2674
2675	for (; Size ? i < *Size : true; ++i, ++VI) {
2676	// The init list might be shorter than the array length.
2677	if (VI == VE)
2678	break;
2679	if (NewB.hasExhaustedBindingLimit())
2680	return NewB.withValuesEscaped(Begin: VI, End: VE);
2681
2682	NonLoc Idx = svalBuilder.makeArrayIndex(idx: i);
2683	const ElementRegion *ER = MRMgr.getElementRegion(elementType: ElementTy, Idx, superRegion: R, Ctx);
2684
2685	if (ElementTy->isStructureOrClassType())
2686	NewB = bindStruct(NewB, ER, *VI);
2687	else if (ElementTy->isArrayType())
2688	NewB = bindArray(NewB, ER, *VI);
2689	else
2690	NewB = bind(B: NewB, L: loc::MemRegionVal(ER), V: *VI);
2691	}
2692
2693	// If the init list is shorter than the array length (or the array has
2694	// variable length), set the array default value. Values that are already set
2695	// are not overwritten.
2696	if (!Size || i < *Size)
2697	NewB = setImplicitDefaultValue(B: NewB, R, T: ElementTy);
2698
2699	return NewB;
2700	}
2701
2702	LimitedRegionBindingsRef
2703	RegionStoreManager::bindVector(LimitedRegionBindingsConstRef B,
2704	const TypedValueRegion *R, SVal V) {
2705	llvm::TimeTraceScope TimeScope("RegionStoreManager::bindVector",
2706	[R]() { return R->getDescriptiveName(); });
2707	if (B.hasExhaustedBindingLimit())
2708	return B.withValuesEscaped(V);
2709
2710	QualType T = R->getValueType();
2711	const VectorType *VT = T->castAs<VectorType>(); // Use castAs for typedefs.
2712
2713	// Handle lazy compound values and symbolic values.
2714	if (isa<nonloc::LazyCompoundVal, nonloc::SymbolVal>(Val: V))
2715	return bindAggregate(B, R, DefaultVal: V);
2716
2717	// We may get non-CompoundVal accidentally due to imprecise cast logic or
2718	// that we are binding symbolic struct value. Kill the field values, and if
2719	// the value is symbolic go and bind it as a "default" binding.
2720	if (!isa<nonloc::CompoundVal>(Val: V)) {
2721	return bindAggregate(B, R, DefaultVal: UnknownVal());
2722	}
2723
2724	QualType ElemType = VT->getElementType();
2725	nonloc::CompoundVal CV = V.castAs<nonloc::CompoundVal>();
2726	nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2727	unsigned index = 0, numElements = VT->getNumElements();
2728	LimitedRegionBindingsRef NewB = B;
2729
2730	for ( ; index != numElements ; ++index) {
2731	if (VI == VE)
2732	break;
2733
2734	if (NewB.hasExhaustedBindingLimit())
2735	return NewB.withValuesEscaped(Begin: VI, End: VE);
2736
2737	NonLoc Idx = svalBuilder.makeArrayIndex(idx: index);
2738	const ElementRegion *ER = MRMgr.getElementRegion(elementType: ElemType, Idx, superRegion: R, Ctx);
2739
2740	if (ElemType->isArrayType())
2741	NewB = bindArray(NewB, ER, *VI);
2742	else if (ElemType->isStructureOrClassType())
2743	NewB = bindStruct(NewB, ER, *VI);
2744	else
2745	NewB = bind(B: NewB, L: loc::MemRegionVal(ER), V: *VI);
2746	}
2747	return NewB;
2748	}
2749
2750	std::optional<SVal>
2751	RegionStoreManager::getUniqueDefaultBinding(RegionBindingsConstRef B,
2752	const TypedValueRegion *R) const {
2753	if (R != R->getBaseRegion())
2754	return std::nullopt;
2755
2756	const auto *Cluster = B.lookup(K: R);
2757	if (!Cluster || !llvm::hasSingleElement(C: *Cluster))
2758	return std::nullopt;
2759
2760	const auto [Key, Value] = *Cluster->begin();
2761	return Key.isDirect() ? std::optional<SVal>{} : Value;
2762	}
2763
2764	std::optional<SVal>
2765	RegionStoreManager::getUniqueDefaultBinding(nonloc::LazyCompoundVal LCV) const {
2766	auto B = getRegionBindings(store: LCV.getStore());
2767	return getUniqueDefaultBinding(B, R: LCV.getRegion());
2768	}
2769
2770	std::optional<LimitedRegionBindingsRef> RegionStoreManager::tryBindSmallStruct(
2771	LimitedRegionBindingsConstRef B, const TypedValueRegion *R,
2772	const RecordDecl *RD, nonloc::LazyCompoundVal LCV) {
2773	if (B.hasExhaustedBindingLimit())
2774	return B.withValuesEscaped(V: LCV);
2775
2776	// If we try to copy a Conjured value representing the value of the whole
2777	// struct, don't try to element-wise copy each field.
2778	// That would unnecessarily bind Derived symbols slicing off the subregion for
2779	// the field from the whole Conjured symbol.
2780	//
2781	// struct Window { int width; int height; };
2782	// Window getWindow(); <-- opaque fn.
2783	// Window w = getWindow(); <-- conjures a new Window.
2784	// Window w2 = w; <-- trivial copy "w", calling "tryBindSmallStruct"
2785	//
2786	// We should not end up with a new Store for "w2" like this:
2787	// Direct [ 0..31]: Derived{Conj{}, w.width}
2788	// Direct [32..63]: Derived{Conj{}, w.height}
2789	// Instead, we should just bind that Conjured value instead.
2790	if (std::optional<SVal> Val = getUniqueDefaultBinding(LCV)) {
2791	return B.addBinding(K: BindingKey::Make(R, k: BindingKey::Default), V: Val.value());
2792	}
2793
2794	FieldVector Fields;
2795
2796	if (const CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(Val: RD))
2797	if (Class->getNumBases() != 0 || Class->getNumVBases() != 0)
2798	return std::nullopt;
2799
2800	for (const auto *FD : RD->fields()) {
2801	if (FD->isUnnamedBitField())
2802	continue;
2803
2804	// If there are too many fields, or if any of the fields are aggregates,
2805	// just use the LCV as a default binding.
2806	if (Fields.size() == SmallStructLimit)
2807	return std::nullopt;
2808
2809	QualType Ty = FD->getType();
2810
2811	// Zero length arrays are basically no-ops, so we also ignore them here.
2812	if (Ty->isConstantArrayType() &&
2813	Ctx.getConstantArrayElementCount(CA: Ctx.getAsConstantArrayType(T: Ty)) == 0)
2814	continue;
2815
2816	if (!(Ty->isScalarType() || Ty->isReferenceType()))
2817	return std::nullopt;
2818
2819	Fields.push_back(Elt: FD);
2820	}
2821
2822	LimitedRegionBindingsRef NewB = B;
2823
2824	for (const FieldDecl *Field : Fields) {
2825	const FieldRegion *SourceFR = MRMgr.getFieldRegion(fd: Field, superRegion: LCV.getRegion());
2826	SVal V = getBindingForField(B: getRegionBindings(store: LCV.getStore()), R: SourceFR);
2827
2828	const FieldRegion *DestFR = MRMgr.getFieldRegion(fd: Field, superRegion: R);
2829	NewB = bind(B: NewB, L: loc::MemRegionVal(DestFR), V);
2830	}
2831
2832	return NewB;
2833	}
2834
2835	LimitedRegionBindingsRef
2836	RegionStoreManager::bindStruct(LimitedRegionBindingsConstRef B,
2837	const TypedValueRegion *R, SVal V) {
2838	llvm::TimeTraceScope TimeScope("RegionStoreManager::bindStruct",
2839	[R]() { return R->getDescriptiveName(); });
2840	if (B.hasExhaustedBindingLimit())
2841	return B.withValuesEscaped(V);
2842
2843	QualType T = R->getValueType();
2844	assert(T->isStructureOrClassType());
2845
2846	const RecordType* RT = T->castAs<RecordType>();
2847	const RecordDecl *RD = RT->getDecl();
2848
2849	if (!RD->isCompleteDefinition())
2850	return B;
2851
2852	// Handle lazy compound values and symbolic values.
2853	if (std::optional<nonloc::LazyCompoundVal> LCV =
2854	V.getAs<nonloc::LazyCompoundVal>()) {
2855	if (std::optional NewB = tryBindSmallStruct(B, R, RD, LCV: *LCV))
2856	return *NewB;
2857	return bindAggregate(B, R, DefaultVal: V);
2858	}
2859	if (isa<nonloc::SymbolVal>(Val: V))
2860	return bindAggregate(B, R, DefaultVal: V);
2861
2862	// We may get non-CompoundVal accidentally due to imprecise cast logic or
2863	// that we are binding symbolic struct value. Kill the field values, and if
2864	// the value is symbolic go and bind it as a "default" binding.
2865	if (V.isUnknown() || !isa<nonloc::CompoundVal>(Val: V))
2866	return bindAggregate(B, R, DefaultVal: UnknownVal());
2867
2868	// The raw CompoundVal is essentially a symbolic InitListExpr: an (immutable)
2869	// list of other values. It appears pretty much only when there's an actual
2870	// initializer list expression in the program, and the analyzer tries to
2871	// unwrap it as soon as possible.
2872	// This code is where such unwrap happens: when the compound value is put into
2873	// the object that it was supposed to initialize (it's an *initializer* list,
2874	// after all), instead of binding the whole value to the whole object, we bind
2875	// sub-values to sub-objects. Sub-values may themselves be compound values,
2876	// and in this case the procedure becomes recursive.
2877	// FIXME: The annoying part about compound values is that they don't carry
2878	// any sort of information about which value corresponds to which sub-object.
2879	// It's simply a list of values in the middle of nowhere; we expect to match
2880	// them to sub-objects, essentially, "by index": first value binds to
2881	// the first field, second value binds to the second field, etc.
2882	// It would have been much safer to organize non-lazy compound values as
2883	// a mapping from fields/bases to values.
2884	const nonloc::CompoundVal& CV = V.castAs<nonloc::CompoundVal>();
2885	nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
2886
2887	LimitedRegionBindingsRef NewB = B;
2888
2889	// In C++17 aggregates may have base classes, handle those as well.
2890	// They appear before fields in the initializer list / compound value.
2891	if (const auto *CRD = dyn_cast<CXXRecordDecl>(Val: RD)) {
2892	// If the object was constructed with a constructor, its value is a
2893	// LazyCompoundVal. If it's a raw CompoundVal, it means that we're
2894	// performing aggregate initialization. The only exception from this
2895	// rule is sending an Objective-C++ message that returns a C++ object
2896	// to a nil receiver; in this case the semantics is to return a
2897	// zero-initialized object even if it's a C++ object that doesn't have
2898	// this sort of constructor; the CompoundVal is empty in this case.
2899	assert((CRD->isAggregate() || (Ctx.getLangOpts().ObjC && VI == VE)) &&
2900	"Non-aggregates are constructed with a constructor!");
2901
2902	for (const auto &B : CRD->bases()) {
2903	// (Multiple inheritance is fine though.)
2904	assert(!B.isVirtual() && "Aggregates cannot have virtual base classes!");
2905
2906	if (VI == VE)
2907	break;
2908	if (NewB.hasExhaustedBindingLimit())
2909	return NewB.withValuesEscaped(Begin: VI, End: VE);
2910
2911	QualType BTy = B.getType();
2912	assert(BTy->isStructureOrClassType() && "Base classes must be classes!");
2913
2914	const CXXRecordDecl *BRD = BTy->getAsCXXRecordDecl();
2915	assert(BRD && "Base classes must be C++ classes!");
2916
2917	const CXXBaseObjectRegion *BR =
2918	MRMgr.getCXXBaseObjectRegion(BaseClass: BRD, Super: R, /*IsVirtual=*/false);
2919
2920	NewB = bindStruct(B: NewB, R: BR, V: *VI);
2921
2922	++VI;
2923	}
2924	}
2925
2926	RecordDecl::field_iterator FI, FE;
2927
2928	for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI) {
2929
2930	if (VI == VE)
2931	break;
2932
2933	if (NewB.hasExhaustedBindingLimit())
2934	return NewB.withValuesEscaped(Begin: VI, End: VE);
2935
2936	// Skip any unnamed bitfields to stay in sync with the initializers.
2937	if (FI->isUnnamedBitField())
2938	continue;
2939
2940	QualType FTy = FI->getType();
2941	const FieldRegion* FR = MRMgr.getFieldRegion(fd: *FI, superRegion: R);
2942
2943	if (FTy->isArrayType())
2944	NewB = bindArray(B: NewB, R: FR, Init: *VI);
2945	else if (FTy->isStructureOrClassType())
2946	NewB = bindStruct(B: NewB, R: FR, V: *VI);
2947	else
2948	NewB = bind(B: NewB, L: loc::MemRegionVal(FR), V: *VI);
2949	++VI;
2950	}
2951
2952	if (NewB.hasExhaustedBindingLimit())
2953	return NewB.withValuesEscaped(Begin: VI, End: VE);
2954
2955	// There may be fewer values in the initialize list than the fields of struct.
2956	if (FI != FE) {
2957	NewB = NewB.addBinding(R, k: BindingKey::Default,
2958	V: svalBuilder.makeIntVal(integer: 0, isUnsigned: false));
2959	}
2960
2961	return NewB;
2962	}
2963
2964	LimitedRegionBindingsRef
2965	RegionStoreManager::bindAggregate(LimitedRegionBindingsConstRef B,
2966	const TypedRegion *R, SVal Val) {
2967	llvm::TimeTraceScope TimeScope("RegionStoreManager::bindAggregate",
2968	[R]() { return R->getDescriptiveName(); });
2969	if (B.hasExhaustedBindingLimit())
2970	return B.withValuesEscaped(V: Val);
2971
2972	// Remove the old bindings, using 'R' as the root of all regions
2973	// we will invalidate. Then add the new binding.
2974	return removeSubRegionBindings(B, Top: R).addBinding(R, k: BindingKey::Default, V: Val);
2975	}
2976
2977	//===----------------------------------------------------------------------===//
2978	// State pruning.
2979	//===----------------------------------------------------------------------===//
2980
2981	namespace {
2982	class RemoveDeadBindingsWorker
2983	: public ClusterAnalysis<RemoveDeadBindingsWorker> {
2984	SmallVector<const SymbolicRegion *, 12> Postponed;
2985	SymbolReaper &SymReaper;
2986	const StackFrameContext *CurrentLCtx;
2987
2988	public:
2989	RemoveDeadBindingsWorker(RegionStoreManager &rm,
2990	ProgramStateManager &stateMgr,
2991	RegionBindingsRef b, SymbolReaper &symReaper,
2992	const StackFrameContext *LCtx)
2993	: ClusterAnalysis<RemoveDeadBindingsWorker>(rm, stateMgr, b),
2994	SymReaper(symReaper), CurrentLCtx(LCtx) {}
2995
2996	// Called by ClusterAnalysis.
2997	void VisitAddedToCluster(const MemRegion *baseR, const ClusterBindings &C);
2998	void VisitCluster(const MemRegion *baseR, const ClusterBindings *C);
2999	using ClusterAnalysis<RemoveDeadBindingsWorker>::VisitCluster;
3000
3001	using ClusterAnalysis::AddToWorkList;
3002
3003	bool AddToWorkList(const MemRegion *R);
3004
3005	bool UpdatePostponed();
3006	void VisitBinding(SVal V);
3007	};
3008	}
3009
3010	bool RemoveDeadBindingsWorker::AddToWorkList(const MemRegion *R) {
3011	const MemRegion *BaseR = R->getBaseRegion();
3012	return AddToWorkList(E: WorkListElement(BaseR), C: getCluster(R: BaseR));
3013	}
3014
3015	void RemoveDeadBindingsWorker::VisitAddedToCluster(const MemRegion *baseR,
3016	const ClusterBindings &C) {
3017
3018	if (const VarRegion *VR = dyn_cast<VarRegion>(Val: baseR)) {
3019	if (SymReaper.isLive(VR))
3020	AddToWorkList(E: baseR, C: &C);
3021
3022	return;
3023	}
3024
3025	if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(Val: baseR)) {
3026	if (SymReaper.isLive(sym: SR->getSymbol()))
3027	AddToWorkList(E: SR, C: &C);
3028	else
3029	Postponed.push_back(Elt: SR);
3030
3031	return;
3032	}
3033
3034	if (isa<NonStaticGlobalSpaceRegion>(Val: baseR)) {
3035	AddToWorkList(E: baseR, C: &C);
3036	return;
3037	}
3038
3039	// CXXThisRegion in the current or parent location context is live.
3040	if (const CXXThisRegion *TR = dyn_cast<CXXThisRegion>(Val: baseR)) {
3041	const auto *StackReg =
3042	cast<StackArgumentsSpaceRegion>(Val: TR->getSuperRegion());
3043	const StackFrameContext *RegCtx = StackReg->getStackFrame();
3044	if (CurrentLCtx &&
3045	(RegCtx == CurrentLCtx || RegCtx->isParentOf(LC: CurrentLCtx)))
3046	AddToWorkList(E: TR, C: &C);
3047	}
3048	}
3049
3050	void RemoveDeadBindingsWorker::VisitCluster(const MemRegion *baseR,
3051	const ClusterBindings *C) {
3052	if (!C)
3053	return;
3054
3055	// Mark the symbol for any SymbolicRegion with live bindings as live itself.
3056	// This means we should continue to track that symbol.
3057	if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(Val: baseR))
3058	SymReaper.markLive(sym: SymR->getSymbol());
3059
3060	for (const auto &[Key, Val] : *C) {
3061	// Element index of a binding key is live.
3062	SymReaper.markElementIndicesLive(region: Key.getRegion());
3063
3064	VisitBinding(V: Val);
3065	}
3066	}
3067
3068	void RemoveDeadBindingsWorker::VisitBinding(SVal V) {
3069	// Is it a LazyCompoundVal? All referenced regions are live as well.
3070	// The LazyCompoundVal itself is not live but should be readable.
3071	if (auto LCS = V.getAs<nonloc::LazyCompoundVal>()) {
3072	SymReaper.markLazilyCopied(region: LCS->getRegion());
3073
3074	for (SVal V : RM.getInterestingValues(LCV: *LCS)) {
3075	if (auto DepLCS = V.getAs<nonloc::LazyCompoundVal>())
3076	SymReaper.markLazilyCopied(region: DepLCS->getRegion());
3077	else
3078	VisitBinding(V);
3079	}
3080
3081	return;
3082	}
3083
3084	// If V is a region, then add it to the worklist.
3085	if (const MemRegion *R = V.getAsRegion()) {
3086	AddToWorkList(R);
3087	SymReaper.markLive(region: R);
3088
3089	// All regions captured by a block are also live.
3090	if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(Val: R)) {
3091	for (auto Var : BR->referenced_vars())
3092	AddToWorkList(R: Var.getCapturedRegion());
3093	}
3094	}
3095
3096
3097	// Update the set of live symbols.
3098	for (SymbolRef Sym : V.symbols())
3099	SymReaper.markLive(sym: Sym);
3100	}
3101
3102	bool RemoveDeadBindingsWorker::UpdatePostponed() {
3103	// See if any postponed SymbolicRegions are actually live now, after
3104	// having done a scan.
3105	bool Changed = false;
3106
3107	for (const SymbolicRegion *SR : Postponed) {
3108	if (SymReaper.isLive(sym: SR->getSymbol())) {
3109	Changed |= AddToWorkList(R: SR);
3110	SR = nullptr;
3111	}
3112	}
3113
3114	return Changed;
3115	}
3116
3117	StoreRef RegionStoreManager::removeDeadBindings(Store store,
3118	const StackFrameContext *LCtx,
3119	SymbolReaper& SymReaper) {
3120	RegionBindingsRef B = getRegionBindings(store);
3121	RemoveDeadBindingsWorker W(*this, StateMgr, B, SymReaper, LCtx);
3122	W.GenerateClusters();
3123
3124	// Enqueue the region roots onto the worklist.
3125	for (const MemRegion *Reg : SymReaper.regions()) {
3126	W.AddToWorkList(R: Reg);
3127	}
3128
3129	do W.RunWorkList(); while (W.UpdatePostponed());
3130
3131	// We have now scanned the store, marking reachable regions and symbols
3132	// as live. We now remove all the regions that are dead from the store
3133	// as well as update DSymbols with the set symbols that are now dead.
3134	for (const MemRegion *Base : llvm::make_first_range(c&: B)) {
3135	// If the cluster has been visited, we know the region has been marked.
3136	// Otherwise, remove the dead entry.
3137	if (!W.isVisited(R: Base))
3138	B = B.removeCluster(BaseRegion: Base);
3139	}
3140
3141	return StoreRef(B.asStore(), *this);
3142	}
3143
3144	//===----------------------------------------------------------------------===//
3145	// Utility methods.
3146	//===----------------------------------------------------------------------===//
3147
3148	void RegionStoreManager::printJson(raw_ostream &Out, Store S, const char *NL,
3149	unsigned int Space, bool IsDot) const {
3150	RegionBindingsRef Bindings = getRegionBindings(store: S);
3151
3152	Indent(Out, Space, IsDot) << "\"store\": ";
3153
3154	if (Bindings.isEmpty()) {
3155	Out << "null," << NL;
3156	return;
3157	}
3158
3159	Out << "{ \"pointer\": \"" << Bindings.asStore() << "\", \"items\": [" << NL;
3160	Bindings.printJson(Out, NL, Space: Space + 1, IsDot);
3161	Indent(Out, Space, IsDot) << "]}," << NL;
3162	}
3163