1 //== MemRegion.cpp - Abstract memory regions for static analysis --*- C++ -*--//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file defines MemRegion and its subclasses.  MemRegion defines a
11 //  partially-typed abstraction of memory useful for path-sensitive dataflow
12 //  analyses.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
17 #include "clang/AST/Attr.h"
18 #include "clang/AST/CharUnits.h"
19 #include "clang/AST/DeclObjC.h"
20 #include "clang/AST/RecordLayout.h"
21 #include "clang/Analysis/AnalysisContext.h"
22 #include "clang/Analysis/Support/BumpVector.h"
23 #include "clang/Basic/SourceManager.h"
24 #include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
25 #include "llvm/Support/raw_ostream.h"
26 
27 using namespace clang;
28 using namespace ento;
29 
30 //===----------------------------------------------------------------------===//
31 // MemRegion Construction.
32 //===----------------------------------------------------------------------===//
33 
34 template<typename RegionTy> struct MemRegionManagerTrait;
35 
36 template <typename RegionTy, typename A1>
37 RegionTy* MemRegionManager::getRegion(const A1 a1) {
38   const typename MemRegionManagerTrait<RegionTy>::SuperRegionTy *superRegion =
39   MemRegionManagerTrait<RegionTy>::getSuperRegion(*this, a1);
40 
41   llvm::FoldingSetNodeID ID;
42   RegionTy::ProfileRegion(ID, a1, superRegion);
43   void *InsertPos;
44   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
45                                                                    InsertPos));
46 
47   if (!R) {
48     R = A.Allocate<RegionTy>();
49     new (R) RegionTy(a1, superRegion);
50     Regions.InsertNode(R, InsertPos);
51   }
52 
53   return R;
54 }
55 
56 template <typename RegionTy, typename A1>
57 RegionTy* MemRegionManager::getSubRegion(const A1 a1,
58                                          const MemRegion *superRegion) {
59   llvm::FoldingSetNodeID ID;
60   RegionTy::ProfileRegion(ID, a1, superRegion);
61   void *InsertPos;
62   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
63                                                                    InsertPos));
64 
65   if (!R) {
66     R = A.Allocate<RegionTy>();
67     new (R) RegionTy(a1, superRegion);
68     Regions.InsertNode(R, InsertPos);
69   }
70 
71   return R;
72 }
73 
74 template <typename RegionTy, typename A1, typename A2>
75 RegionTy* MemRegionManager::getRegion(const A1 a1, const A2 a2) {
76   const typename MemRegionManagerTrait<RegionTy>::SuperRegionTy *superRegion =
77   MemRegionManagerTrait<RegionTy>::getSuperRegion(*this, a1, a2);
78 
79   llvm::FoldingSetNodeID ID;
80   RegionTy::ProfileRegion(ID, a1, a2, superRegion);
81   void *InsertPos;
82   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
83                                                                    InsertPos));
84 
85   if (!R) {
86     R = A.Allocate<RegionTy>();
87     new (R) RegionTy(a1, a2, superRegion);
88     Regions.InsertNode(R, InsertPos);
89   }
90 
91   return R;
92 }
93 
94 template <typename RegionTy, typename A1, typename A2>
95 RegionTy* MemRegionManager::getSubRegion(const A1 a1, const A2 a2,
96                                          const MemRegion *superRegion) {
97   llvm::FoldingSetNodeID ID;
98   RegionTy::ProfileRegion(ID, a1, a2, superRegion);
99   void *InsertPos;
100   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
101                                                                    InsertPos));
102 
103   if (!R) {
104     R = A.Allocate<RegionTy>();
105     new (R) RegionTy(a1, a2, superRegion);
106     Regions.InsertNode(R, InsertPos);
107   }
108 
109   return R;
110 }
111 
112 template <typename RegionTy, typename A1, typename A2, typename A3>
113 RegionTy* MemRegionManager::getSubRegion(const A1 a1, const A2 a2, const A3 a3,
114                                          const MemRegion *superRegion) {
115   llvm::FoldingSetNodeID ID;
116   RegionTy::ProfileRegion(ID, a1, a2, a3, superRegion);
117   void *InsertPos;
118   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
119                                                                    InsertPos));
120 
121   if (!R) {
122     R = A.Allocate<RegionTy>();
123     new (R) RegionTy(a1, a2, a3, superRegion);
124     Regions.InsertNode(R, InsertPos);
125   }
126 
127   return R;
128 }
129 
130 //===----------------------------------------------------------------------===//
131 // Object destruction.
132 //===----------------------------------------------------------------------===//
133 
134 MemRegion::~MemRegion() {}
135 
136 MemRegionManager::~MemRegionManager() {
137   // All regions and their data are BumpPtrAllocated.  No need to call
138   // their destructors.
139 }
140 
141 //===----------------------------------------------------------------------===//
142 // Basic methods.
143 //===----------------------------------------------------------------------===//
144 
145 bool SubRegion::isSubRegionOf(const MemRegion* R) const {
146   const MemRegion* r = getSuperRegion();
147   while (r != nullptr) {
148     if (r == R)
149       return true;
150     if (const SubRegion* sr = dyn_cast<SubRegion>(r))
151       r = sr->getSuperRegion();
152     else
153       break;
154   }
155   return false;
156 }
157 
158 MemRegionManager* SubRegion::getMemRegionManager() const {
159   const SubRegion* r = this;
160   do {
161     const MemRegion *superRegion = r->getSuperRegion();
162     if (const SubRegion *sr = dyn_cast<SubRegion>(superRegion)) {
163       r = sr;
164       continue;
165     }
166     return superRegion->getMemRegionManager();
167   } while (1);
168 }
169 
170 const StackFrameContext *VarRegion::getStackFrame() const {
171   const StackSpaceRegion *SSR = dyn_cast<StackSpaceRegion>(getMemorySpace());
172   return SSR ? SSR->getStackFrame() : nullptr;
173 }
174 
175 //===----------------------------------------------------------------------===//
176 // Region extents.
177 //===----------------------------------------------------------------------===//
178 
179 DefinedOrUnknownSVal TypedValueRegion::getExtent(SValBuilder &svalBuilder) const {
180   ASTContext &Ctx = svalBuilder.getContext();
181   QualType T = getDesugaredValueType(Ctx);
182 
183   if (isa<VariableArrayType>(T))
184     return nonloc::SymbolVal(svalBuilder.getSymbolManager().getExtentSymbol(this));
185   if (T->isIncompleteType())
186     return UnknownVal();
187 
188   CharUnits size = Ctx.getTypeSizeInChars(T);
189   QualType sizeTy = svalBuilder.getArrayIndexType();
190   return svalBuilder.makeIntVal(size.getQuantity(), sizeTy);
191 }
192 
193 DefinedOrUnknownSVal FieldRegion::getExtent(SValBuilder &svalBuilder) const {
194   // Force callers to deal with bitfields explicitly.
195   if (getDecl()->isBitField())
196     return UnknownVal();
197 
198   DefinedOrUnknownSVal Extent = DeclRegion::getExtent(svalBuilder);
199 
200   // A zero-length array at the end of a struct often stands for dynamically-
201   // allocated extra memory.
202   if (Extent.isZeroConstant()) {
203     QualType T = getDesugaredValueType(svalBuilder.getContext());
204 
205     if (isa<ConstantArrayType>(T))
206       return UnknownVal();
207   }
208 
209   return Extent;
210 }
211 
212 DefinedOrUnknownSVal AllocaRegion::getExtent(SValBuilder &svalBuilder) const {
213   return nonloc::SymbolVal(svalBuilder.getSymbolManager().getExtentSymbol(this));
214 }
215 
216 DefinedOrUnknownSVal SymbolicRegion::getExtent(SValBuilder &svalBuilder) const {
217   return nonloc::SymbolVal(svalBuilder.getSymbolManager().getExtentSymbol(this));
218 }
219 
220 DefinedOrUnknownSVal StringRegion::getExtent(SValBuilder &svalBuilder) const {
221   return svalBuilder.makeIntVal(getStringLiteral()->getByteLength()+1,
222                                 svalBuilder.getArrayIndexType());
223 }
224 
225 ObjCIvarRegion::ObjCIvarRegion(const ObjCIvarDecl *ivd, const MemRegion* sReg)
226   : DeclRegion(ivd, sReg, ObjCIvarRegionKind) {}
227 
228 const ObjCIvarDecl *ObjCIvarRegion::getDecl() const {
229   return cast<ObjCIvarDecl>(D);
230 }
231 
232 QualType ObjCIvarRegion::getValueType() const {
233   return getDecl()->getType();
234 }
235 
236 QualType CXXBaseObjectRegion::getValueType() const {
237   return QualType(getDecl()->getTypeForDecl(), 0);
238 }
239 
240 //===----------------------------------------------------------------------===//
241 // FoldingSet profiling.
242 //===----------------------------------------------------------------------===//
243 
244 void MemSpaceRegion::Profile(llvm::FoldingSetNodeID &ID) const {
245   ID.AddInteger(static_cast<unsigned>(getKind()));
246 }
247 
248 void StackSpaceRegion::Profile(llvm::FoldingSetNodeID &ID) const {
249   ID.AddInteger(static_cast<unsigned>(getKind()));
250   ID.AddPointer(getStackFrame());
251 }
252 
253 void StaticGlobalSpaceRegion::Profile(llvm::FoldingSetNodeID &ID) const {
254   ID.AddInteger(static_cast<unsigned>(getKind()));
255   ID.AddPointer(getCodeRegion());
256 }
257 
258 void StringRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
259                                  const StringLiteral* Str,
260                                  const MemRegion* superRegion) {
261   ID.AddInteger(static_cast<unsigned>(StringRegionKind));
262   ID.AddPointer(Str);
263   ID.AddPointer(superRegion);
264 }
265 
266 void ObjCStringRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
267                                      const ObjCStringLiteral* Str,
268                                      const MemRegion* superRegion) {
269   ID.AddInteger(static_cast<unsigned>(ObjCStringRegionKind));
270   ID.AddPointer(Str);
271   ID.AddPointer(superRegion);
272 }
273 
274 void AllocaRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
275                                  const Expr *Ex, unsigned cnt,
276                                  const MemRegion *superRegion) {
277   ID.AddInteger(static_cast<unsigned>(AllocaRegionKind));
278   ID.AddPointer(Ex);
279   ID.AddInteger(cnt);
280   ID.AddPointer(superRegion);
281 }
282 
283 void AllocaRegion::Profile(llvm::FoldingSetNodeID& ID) const {
284   ProfileRegion(ID, Ex, Cnt, superRegion);
285 }
286 
287 void CompoundLiteralRegion::Profile(llvm::FoldingSetNodeID& ID) const {
288   CompoundLiteralRegion::ProfileRegion(ID, CL, superRegion);
289 }
290 
291 void CompoundLiteralRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
292                                           const CompoundLiteralExpr *CL,
293                                           const MemRegion* superRegion) {
294   ID.AddInteger(static_cast<unsigned>(CompoundLiteralRegionKind));
295   ID.AddPointer(CL);
296   ID.AddPointer(superRegion);
297 }
298 
299 void CXXThisRegion::ProfileRegion(llvm::FoldingSetNodeID &ID,
300                                   const PointerType *PT,
301                                   const MemRegion *sRegion) {
302   ID.AddInteger(static_cast<unsigned>(CXXThisRegionKind));
303   ID.AddPointer(PT);
304   ID.AddPointer(sRegion);
305 }
306 
307 void CXXThisRegion::Profile(llvm::FoldingSetNodeID &ID) const {
308   CXXThisRegion::ProfileRegion(ID, ThisPointerTy, superRegion);
309 }
310 
311 void ObjCIvarRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
312                                    const ObjCIvarDecl *ivd,
313                                    const MemRegion* superRegion) {
314   DeclRegion::ProfileRegion(ID, ivd, superRegion, ObjCIvarRegionKind);
315 }
316 
317 void DeclRegion::ProfileRegion(llvm::FoldingSetNodeID& ID, const Decl *D,
318                                const MemRegion* superRegion, Kind k) {
319   ID.AddInteger(static_cast<unsigned>(k));
320   ID.AddPointer(D);
321   ID.AddPointer(superRegion);
322 }
323 
324 void DeclRegion::Profile(llvm::FoldingSetNodeID& ID) const {
325   DeclRegion::ProfileRegion(ID, D, superRegion, getKind());
326 }
327 
328 void VarRegion::Profile(llvm::FoldingSetNodeID &ID) const {
329   VarRegion::ProfileRegion(ID, getDecl(), superRegion);
330 }
331 
332 void SymbolicRegion::ProfileRegion(llvm::FoldingSetNodeID& ID, SymbolRef sym,
333                                    const MemRegion *sreg) {
334   ID.AddInteger(static_cast<unsigned>(MemRegion::SymbolicRegionKind));
335   ID.Add(sym);
336   ID.AddPointer(sreg);
337 }
338 
339 void SymbolicRegion::Profile(llvm::FoldingSetNodeID& ID) const {
340   SymbolicRegion::ProfileRegion(ID, sym, getSuperRegion());
341 }
342 
343 void ElementRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
344                                   QualType ElementType, SVal Idx,
345                                   const MemRegion* superRegion) {
346   ID.AddInteger(MemRegion::ElementRegionKind);
347   ID.Add(ElementType);
348   ID.AddPointer(superRegion);
349   Idx.Profile(ID);
350 }
351 
352 void ElementRegion::Profile(llvm::FoldingSetNodeID& ID) const {
353   ElementRegion::ProfileRegion(ID, ElementType, Index, superRegion);
354 }
355 
356 void FunctionCodeRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
357                                        const NamedDecl *FD,
358                                        const MemRegion*) {
359   ID.AddInteger(MemRegion::FunctionCodeRegionKind);
360   ID.AddPointer(FD);
361 }
362 
363 void FunctionCodeRegion::Profile(llvm::FoldingSetNodeID& ID) const {
364   FunctionCodeRegion::ProfileRegion(ID, FD, superRegion);
365 }
366 
367 void BlockCodeRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
368                                     const BlockDecl *BD, CanQualType,
369                                     const AnalysisDeclContext *AC,
370                                     const MemRegion*) {
371   ID.AddInteger(MemRegion::BlockCodeRegionKind);
372   ID.AddPointer(BD);
373 }
374 
375 void BlockCodeRegion::Profile(llvm::FoldingSetNodeID& ID) const {
376   BlockCodeRegion::ProfileRegion(ID, BD, locTy, AC, superRegion);
377 }
378 
379 void BlockDataRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
380                                     const BlockCodeRegion *BC,
381                                     const LocationContext *LC,
382                                     unsigned BlkCount,
383                                     const MemRegion *sReg) {
384   ID.AddInteger(MemRegion::BlockDataRegionKind);
385   ID.AddPointer(BC);
386   ID.AddPointer(LC);
387   ID.AddInteger(BlkCount);
388   ID.AddPointer(sReg);
389 }
390 
391 void BlockDataRegion::Profile(llvm::FoldingSetNodeID& ID) const {
392   BlockDataRegion::ProfileRegion(ID, BC, LC, BlockCount, getSuperRegion());
393 }
394 
395 void CXXTempObjectRegion::ProfileRegion(llvm::FoldingSetNodeID &ID,
396                                         Expr const *Ex,
397                                         const MemRegion *sReg) {
398   ID.AddPointer(Ex);
399   ID.AddPointer(sReg);
400 }
401 
402 void CXXTempObjectRegion::Profile(llvm::FoldingSetNodeID &ID) const {
403   ProfileRegion(ID, Ex, getSuperRegion());
404 }
405 
406 void CXXBaseObjectRegion::ProfileRegion(llvm::FoldingSetNodeID &ID,
407                                         const CXXRecordDecl *RD,
408                                         bool IsVirtual,
409                                         const MemRegion *SReg) {
410   ID.AddPointer(RD);
411   ID.AddBoolean(IsVirtual);
412   ID.AddPointer(SReg);
413 }
414 
415 void CXXBaseObjectRegion::Profile(llvm::FoldingSetNodeID &ID) const {
416   ProfileRegion(ID, getDecl(), isVirtual(), superRegion);
417 }
418 
419 //===----------------------------------------------------------------------===//
420 // Region anchors.
421 //===----------------------------------------------------------------------===//
422 
423 void GlobalsSpaceRegion::anchor() { }
424 void HeapSpaceRegion::anchor() { }
425 void UnknownSpaceRegion::anchor() { }
426 void StackLocalsSpaceRegion::anchor() { }
427 void StackArgumentsSpaceRegion::anchor() { }
428 void TypedRegion::anchor() { }
429 void TypedValueRegion::anchor() { }
430 void CodeTextRegion::anchor() { }
431 void SubRegion::anchor() { }
432 
433 //===----------------------------------------------------------------------===//
434 // Region pretty-printing.
435 //===----------------------------------------------------------------------===//
436 
437 LLVM_DUMP_METHOD void MemRegion::dump() const {
438   dumpToStream(llvm::errs());
439 }
440 
441 std::string MemRegion::getString() const {
442   std::string s;
443   llvm::raw_string_ostream os(s);
444   dumpToStream(os);
445   return os.str();
446 }
447 
448 void MemRegion::dumpToStream(raw_ostream &os) const {
449   os << "<Unknown Region>";
450 }
451 
452 void AllocaRegion::dumpToStream(raw_ostream &os) const {
453   os << "alloca{" << static_cast<const void*>(Ex) << ',' << Cnt << '}';
454 }
455 
456 void FunctionCodeRegion::dumpToStream(raw_ostream &os) const {
457   os << "code{" << getDecl()->getDeclName().getAsString() << '}';
458 }
459 
460 void BlockCodeRegion::dumpToStream(raw_ostream &os) const {
461   os << "block_code{" << static_cast<const void*>(this) << '}';
462 }
463 
464 void BlockDataRegion::dumpToStream(raw_ostream &os) const {
465   os << "block_data{" << BC;
466   os << "; ";
467   for (BlockDataRegion::referenced_vars_iterator
468          I = referenced_vars_begin(),
469          E = referenced_vars_end(); I != E; ++I)
470     os << "(" << I.getCapturedRegion() << "," <<
471                  I.getOriginalRegion() << ") ";
472   os << '}';
473 }
474 
475 void CompoundLiteralRegion::dumpToStream(raw_ostream &os) const {
476   // FIXME: More elaborate pretty-printing.
477   os << "{ " << static_cast<const void*>(CL) <<  " }";
478 }
479 
480 void CXXTempObjectRegion::dumpToStream(raw_ostream &os) const {
481   os << "temp_object{" << getValueType().getAsString() << ','
482      << static_cast<const void*>(Ex) << '}';
483 }
484 
485 void CXXBaseObjectRegion::dumpToStream(raw_ostream &os) const {
486   os << "base{" << superRegion << ',' << getDecl()->getName() << '}';
487 }
488 
489 void CXXThisRegion::dumpToStream(raw_ostream &os) const {
490   os << "this";
491 }
492 
493 void ElementRegion::dumpToStream(raw_ostream &os) const {
494   os << "element{" << superRegion << ','
495      << Index << ',' << getElementType().getAsString() << '}';
496 }
497 
498 void FieldRegion::dumpToStream(raw_ostream &os) const {
499   os << superRegion << "->" << *getDecl();
500 }
501 
502 void ObjCIvarRegion::dumpToStream(raw_ostream &os) const {
503   os << "ivar{" << superRegion << ',' << *getDecl() << '}';
504 }
505 
506 void StringRegion::dumpToStream(raw_ostream &os) const {
507   assert(Str != nullptr && "Expecting non-null StringLiteral");
508   Str->printPretty(os, nullptr, PrintingPolicy(getContext().getLangOpts()));
509 }
510 
511 void ObjCStringRegion::dumpToStream(raw_ostream &os) const {
512   assert(Str != nullptr && "Expecting non-null ObjCStringLiteral");
513   Str->printPretty(os, nullptr, PrintingPolicy(getContext().getLangOpts()));
514 }
515 
516 void SymbolicRegion::dumpToStream(raw_ostream &os) const {
517   os << "SymRegion{" << sym << '}';
518 }
519 
520 void VarRegion::dumpToStream(raw_ostream &os) const {
521   os << *cast<VarDecl>(D);
522 }
523 
524 LLVM_DUMP_METHOD void RegionRawOffset::dump() const {
525   dumpToStream(llvm::errs());
526 }
527 
528 void RegionRawOffset::dumpToStream(raw_ostream &os) const {
529   os << "raw_offset{" << getRegion() << ',' << getOffset().getQuantity() << '}';
530 }
531 
532 void CodeSpaceRegion::dumpToStream(raw_ostream &os) const {
533   os << "CodeSpaceRegion";
534 }
535 
536 void StaticGlobalSpaceRegion::dumpToStream(raw_ostream &os) const {
537   os << "StaticGlobalsMemSpace{" << CR << '}';
538 }
539 
540 void GlobalInternalSpaceRegion::dumpToStream(raw_ostream &os) const {
541   os << "GlobalInternalSpaceRegion";
542 }
543 
544 void GlobalSystemSpaceRegion::dumpToStream(raw_ostream &os) const {
545   os << "GlobalSystemSpaceRegion";
546 }
547 
548 void GlobalImmutableSpaceRegion::dumpToStream(raw_ostream &os) const {
549   os << "GlobalImmutableSpaceRegion";
550 }
551 
552 void HeapSpaceRegion::dumpToStream(raw_ostream &os) const {
553   os << "HeapSpaceRegion";
554 }
555 
556 void UnknownSpaceRegion::dumpToStream(raw_ostream &os) const {
557   os << "UnknownSpaceRegion";
558 }
559 
560 void StackArgumentsSpaceRegion::dumpToStream(raw_ostream &os) const {
561   os << "StackArgumentsSpaceRegion";
562 }
563 
564 void StackLocalsSpaceRegion::dumpToStream(raw_ostream &os) const {
565   os << "StackLocalsSpaceRegion";
566 }
567 
568 bool MemRegion::canPrintPretty() const {
569   return canPrintPrettyAsExpr();
570 }
571 
572 bool MemRegion::canPrintPrettyAsExpr() const {
573   return false;
574 }
575 
576 void MemRegion::printPretty(raw_ostream &os) const {
577   assert(canPrintPretty() && "This region cannot be printed pretty.");
578   os << "'";
579   printPrettyAsExpr(os);
580   os << "'";
581 }
582 
583 void MemRegion::printPrettyAsExpr(raw_ostream &os) const {
584   llvm_unreachable("This region cannot be printed pretty.");
585 }
586 
587 bool VarRegion::canPrintPrettyAsExpr() const {
588   return true;
589 }
590 
591 void VarRegion::printPrettyAsExpr(raw_ostream &os) const {
592   os << getDecl()->getName();
593 }
594 
595 bool ObjCIvarRegion::canPrintPrettyAsExpr() const {
596   return true;
597 }
598 
599 void ObjCIvarRegion::printPrettyAsExpr(raw_ostream &os) const {
600   os << getDecl()->getName();
601 }
602 
603 bool FieldRegion::canPrintPretty() const {
604   return true;
605 }
606 
607 bool FieldRegion::canPrintPrettyAsExpr() const {
608   return superRegion->canPrintPrettyAsExpr();
609 }
610 
611 void FieldRegion::printPrettyAsExpr(raw_ostream &os) const {
612   assert(canPrintPrettyAsExpr());
613   superRegion->printPrettyAsExpr(os);
614   os << "." << getDecl()->getName();
615 }
616 
617 void FieldRegion::printPretty(raw_ostream &os) const {
618   if (canPrintPrettyAsExpr()) {
619     os << "\'";
620     printPrettyAsExpr(os);
621     os << "'";
622   } else {
623     os << "field " << "\'" << getDecl()->getName() << "'";
624   }
625 }
626 
627 bool CXXBaseObjectRegion::canPrintPrettyAsExpr() const {
628   return superRegion->canPrintPrettyAsExpr();
629 }
630 
631 void CXXBaseObjectRegion::printPrettyAsExpr(raw_ostream &os) const {
632   superRegion->printPrettyAsExpr(os);
633 }
634 
635 //===----------------------------------------------------------------------===//
636 // MemRegionManager methods.
637 //===----------------------------------------------------------------------===//
638 
639 template <typename REG>
640 const REG *MemRegionManager::LazyAllocate(REG*& region) {
641   if (!region) {
642     region = A.Allocate<REG>();
643     new (region) REG(this);
644   }
645 
646   return region;
647 }
648 
649 template <typename REG, typename ARG>
650 const REG *MemRegionManager::LazyAllocate(REG*& region, ARG a) {
651   if (!region) {
652     region = A.Allocate<REG>();
653     new (region) REG(this, a);
654   }
655 
656   return region;
657 }
658 
659 const StackLocalsSpaceRegion*
660 MemRegionManager::getStackLocalsRegion(const StackFrameContext *STC) {
661   assert(STC);
662   StackLocalsSpaceRegion *&R = StackLocalsSpaceRegions[STC];
663 
664   if (R)
665     return R;
666 
667   R = A.Allocate<StackLocalsSpaceRegion>();
668   new (R) StackLocalsSpaceRegion(this, STC);
669   return R;
670 }
671 
672 const StackArgumentsSpaceRegion *
673 MemRegionManager::getStackArgumentsRegion(const StackFrameContext *STC) {
674   assert(STC);
675   StackArgumentsSpaceRegion *&R = StackArgumentsSpaceRegions[STC];
676 
677   if (R)
678     return R;
679 
680   R = A.Allocate<StackArgumentsSpaceRegion>();
681   new (R) StackArgumentsSpaceRegion(this, STC);
682   return R;
683 }
684 
685 const GlobalsSpaceRegion
686 *MemRegionManager::getGlobalsRegion(MemRegion::Kind K,
687                                     const CodeTextRegion *CR) {
688   if (!CR) {
689     if (K == MemRegion::GlobalSystemSpaceRegionKind)
690       return LazyAllocate(SystemGlobals);
691     if (K == MemRegion::GlobalImmutableSpaceRegionKind)
692       return LazyAllocate(ImmutableGlobals);
693     assert(K == MemRegion::GlobalInternalSpaceRegionKind);
694     return LazyAllocate(InternalGlobals);
695   }
696 
697   assert(K == MemRegion::StaticGlobalSpaceRegionKind);
698   StaticGlobalSpaceRegion *&R = StaticsGlobalSpaceRegions[CR];
699   if (R)
700     return R;
701 
702   R = A.Allocate<StaticGlobalSpaceRegion>();
703   new (R) StaticGlobalSpaceRegion(this, CR);
704   return R;
705 }
706 
707 const HeapSpaceRegion *MemRegionManager::getHeapRegion() {
708   return LazyAllocate(heap);
709 }
710 
711 const UnknownSpaceRegion *MemRegionManager::getUnknownRegion() {
712   return LazyAllocate(unknown);
713 }
714 
715 const CodeSpaceRegion *MemRegionManager::getCodeRegion() {
716   return LazyAllocate(code);
717 }
718 
719 //===----------------------------------------------------------------------===//
720 // Constructing regions.
721 //===----------------------------------------------------------------------===//
722 const StringRegion* MemRegionManager::getStringRegion(const StringLiteral* Str){
723   return getSubRegion<StringRegion>(Str, getGlobalsRegion());
724 }
725 
726 const ObjCStringRegion *
727 MemRegionManager::getObjCStringRegion(const ObjCStringLiteral* Str){
728   return getSubRegion<ObjCStringRegion>(Str, getGlobalsRegion());
729 }
730 
731 /// Look through a chain of LocationContexts to either find the
732 /// StackFrameContext that matches a DeclContext, or find a VarRegion
733 /// for a variable captured by a block.
734 static llvm::PointerUnion<const StackFrameContext *, const VarRegion *>
735 getStackOrCaptureRegionForDeclContext(const LocationContext *LC,
736                                       const DeclContext *DC,
737                                       const VarDecl *VD) {
738   while (LC) {
739     if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC)) {
740       if (cast<DeclContext>(SFC->getDecl()) == DC)
741         return SFC;
742     }
743     if (const BlockInvocationContext *BC =
744         dyn_cast<BlockInvocationContext>(LC)) {
745       const BlockDataRegion *BR =
746         static_cast<const BlockDataRegion*>(BC->getContextData());
747       // FIXME: This can be made more efficient.
748       for (BlockDataRegion::referenced_vars_iterator
749            I = BR->referenced_vars_begin(),
750            E = BR->referenced_vars_end(); I != E; ++I) {
751         if (const VarRegion *VR = dyn_cast<VarRegion>(I.getOriginalRegion()))
752           if (VR->getDecl() == VD)
753             return cast<VarRegion>(I.getCapturedRegion());
754       }
755     }
756 
757     LC = LC->getParent();
758   }
759   return (const StackFrameContext *)nullptr;
760 }
761 
762 const VarRegion* MemRegionManager::getVarRegion(const VarDecl *D,
763                                                 const LocationContext *LC) {
764   const MemRegion *sReg = nullptr;
765 
766   if (D->hasGlobalStorage() && !D->isStaticLocal()) {
767 
768     // First handle the globals defined in system headers.
769     if (C.getSourceManager().isInSystemHeader(D->getLocation())) {
770       // Whitelist the system globals which often DO GET modified, assume the
771       // rest are immutable.
772       if (D->getName().find("errno") != StringRef::npos)
773         sReg = getGlobalsRegion(MemRegion::GlobalSystemSpaceRegionKind);
774       else
775         sReg = getGlobalsRegion(MemRegion::GlobalImmutableSpaceRegionKind);
776 
777     // Treat other globals as GlobalInternal unless they are constants.
778     } else {
779       QualType GQT = D->getType();
780       const Type *GT = GQT.getTypePtrOrNull();
781       // TODO: We could walk the complex types here and see if everything is
782       // constified.
783       if (GT && GQT.isConstQualified() && GT->isArithmeticType())
784         sReg = getGlobalsRegion(MemRegion::GlobalImmutableSpaceRegionKind);
785       else
786         sReg = getGlobalsRegion();
787     }
788 
789   // Finally handle static locals.
790   } else {
791     // FIXME: Once we implement scope handling, we will need to properly lookup
792     // 'D' to the proper LocationContext.
793     const DeclContext *DC = D->getDeclContext();
794     llvm::PointerUnion<const StackFrameContext *, const VarRegion *> V =
795       getStackOrCaptureRegionForDeclContext(LC, DC, D);
796 
797     if (V.is<const VarRegion*>())
798       return V.get<const VarRegion*>();
799 
800     const StackFrameContext *STC = V.get<const StackFrameContext*>();
801 
802     if (!STC)
803       sReg = getUnknownRegion();
804     else {
805       if (D->hasLocalStorage()) {
806         sReg = isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)
807                ? static_cast<const MemRegion*>(getStackArgumentsRegion(STC))
808                : static_cast<const MemRegion*>(getStackLocalsRegion(STC));
809       }
810       else {
811         assert(D->isStaticLocal());
812         const Decl *STCD = STC->getDecl();
813         if (isa<FunctionDecl>(STCD) || isa<ObjCMethodDecl>(STCD))
814           sReg = getGlobalsRegion(MemRegion::StaticGlobalSpaceRegionKind,
815                                   getFunctionCodeRegion(cast<NamedDecl>(STCD)));
816         else if (const BlockDecl *BD = dyn_cast<BlockDecl>(STCD)) {
817           // FIXME: The fallback type here is totally bogus -- though it should
818           // never be queried, it will prevent uniquing with the real
819           // BlockCodeRegion. Ideally we'd fix the AST so that we always had a
820           // signature.
821           QualType T;
822           if (const TypeSourceInfo *TSI = BD->getSignatureAsWritten())
823             T = TSI->getType();
824           if (T.isNull())
825             T = getContext().VoidTy;
826           if (!T->getAs<FunctionType>())
827             T = getContext().getFunctionNoProtoType(T);
828           T = getContext().getBlockPointerType(T);
829 
830           const BlockCodeRegion *BTR =
831             getBlockCodeRegion(BD, C.getCanonicalType(T),
832                                STC->getAnalysisDeclContext());
833           sReg = getGlobalsRegion(MemRegion::StaticGlobalSpaceRegionKind,
834                                   BTR);
835         }
836         else {
837           sReg = getGlobalsRegion();
838         }
839       }
840     }
841   }
842 
843   return getSubRegion<VarRegion>(D, sReg);
844 }
845 
846 const VarRegion *MemRegionManager::getVarRegion(const VarDecl *D,
847                                                 const MemRegion *superR) {
848   return getSubRegion<VarRegion>(D, superR);
849 }
850 
851 const BlockDataRegion *
852 MemRegionManager::getBlockDataRegion(const BlockCodeRegion *BC,
853                                      const LocationContext *LC,
854                                      unsigned blockCount) {
855   const MemRegion *sReg = nullptr;
856   const BlockDecl *BD = BC->getDecl();
857   if (!BD->hasCaptures()) {
858     // This handles 'static' blocks.
859     sReg = getGlobalsRegion(MemRegion::GlobalImmutableSpaceRegionKind);
860   }
861   else {
862     if (LC) {
863       // FIXME: Once we implement scope handling, we want the parent region
864       // to be the scope.
865       const StackFrameContext *STC = LC->getCurrentStackFrame();
866       assert(STC);
867       sReg = getStackLocalsRegion(STC);
868     }
869     else {
870       // We allow 'LC' to be NULL for cases where want BlockDataRegions
871       // without context-sensitivity.
872       sReg = getUnknownRegion();
873     }
874   }
875 
876   return getSubRegion<BlockDataRegion>(BC, LC, blockCount, sReg);
877 }
878 
879 const CXXTempObjectRegion *
880 MemRegionManager::getCXXStaticTempObjectRegion(const Expr *Ex) {
881   return getSubRegion<CXXTempObjectRegion>(
882       Ex, getGlobalsRegion(MemRegion::GlobalInternalSpaceRegionKind, nullptr));
883 }
884 
885 const CompoundLiteralRegion*
886 MemRegionManager::getCompoundLiteralRegion(const CompoundLiteralExpr *CL,
887                                            const LocationContext *LC) {
888   const MemRegion *sReg = nullptr;
889 
890   if (CL->isFileScope())
891     sReg = getGlobalsRegion();
892   else {
893     const StackFrameContext *STC = LC->getCurrentStackFrame();
894     assert(STC);
895     sReg = getStackLocalsRegion(STC);
896   }
897 
898   return getSubRegion<CompoundLiteralRegion>(CL, sReg);
899 }
900 
901 const ElementRegion*
902 MemRegionManager::getElementRegion(QualType elementType, NonLoc Idx,
903                                    const MemRegion* superRegion,
904                                    ASTContext &Ctx){
905   QualType T = Ctx.getCanonicalType(elementType).getUnqualifiedType();
906 
907   llvm::FoldingSetNodeID ID;
908   ElementRegion::ProfileRegion(ID, T, Idx, superRegion);
909 
910   void *InsertPos;
911   MemRegion* data = Regions.FindNodeOrInsertPos(ID, InsertPos);
912   ElementRegion* R = cast_or_null<ElementRegion>(data);
913 
914   if (!R) {
915     R = A.Allocate<ElementRegion>();
916     new (R) ElementRegion(T, Idx, superRegion);
917     Regions.InsertNode(R, InsertPos);
918   }
919 
920   return R;
921 }
922 
923 const FunctionCodeRegion *
924 MemRegionManager::getFunctionCodeRegion(const NamedDecl *FD) {
925   return getSubRegion<FunctionCodeRegion>(FD, getCodeRegion());
926 }
927 
928 const BlockCodeRegion *
929 MemRegionManager::getBlockCodeRegion(const BlockDecl *BD, CanQualType locTy,
930                                      AnalysisDeclContext *AC) {
931   return getSubRegion<BlockCodeRegion>(BD, locTy, AC, getCodeRegion());
932 }
933 
934 
935 /// getSymbolicRegion - Retrieve or create a "symbolic" memory region.
936 const SymbolicRegion *MemRegionManager::getSymbolicRegion(SymbolRef sym) {
937   return getSubRegion<SymbolicRegion>(sym, getUnknownRegion());
938 }
939 
940 const SymbolicRegion *MemRegionManager::getSymbolicHeapRegion(SymbolRef Sym) {
941   return getSubRegion<SymbolicRegion>(Sym, getHeapRegion());
942 }
943 
944 const FieldRegion*
945 MemRegionManager::getFieldRegion(const FieldDecl *d,
946                                  const MemRegion* superRegion){
947   return getSubRegion<FieldRegion>(d, superRegion);
948 }
949 
950 const ObjCIvarRegion*
951 MemRegionManager::getObjCIvarRegion(const ObjCIvarDecl *d,
952                                     const MemRegion* superRegion) {
953   return getSubRegion<ObjCIvarRegion>(d, superRegion);
954 }
955 
956 const CXXTempObjectRegion*
957 MemRegionManager::getCXXTempObjectRegion(Expr const *E,
958                                          LocationContext const *LC) {
959   const StackFrameContext *SFC = LC->getCurrentStackFrame();
960   assert(SFC);
961   return getSubRegion<CXXTempObjectRegion>(E, getStackLocalsRegion(SFC));
962 }
963 
964 /// Checks whether \p BaseClass is a valid virtual or direct non-virtual base
965 /// class of the type of \p Super.
966 static bool isValidBaseClass(const CXXRecordDecl *BaseClass,
967                              const TypedValueRegion *Super,
968                              bool IsVirtual) {
969   BaseClass = BaseClass->getCanonicalDecl();
970 
971   const CXXRecordDecl *Class = Super->getValueType()->getAsCXXRecordDecl();
972   if (!Class)
973     return true;
974 
975   if (IsVirtual)
976     return Class->isVirtuallyDerivedFrom(BaseClass);
977 
978   for (const auto &I : Class->bases()) {
979     if (I.getType()->getAsCXXRecordDecl()->getCanonicalDecl() == BaseClass)
980       return true;
981   }
982 
983   return false;
984 }
985 
986 const CXXBaseObjectRegion *
987 MemRegionManager::getCXXBaseObjectRegion(const CXXRecordDecl *RD,
988                                          const MemRegion *Super,
989                                          bool IsVirtual) {
990   if (isa<TypedValueRegion>(Super)) {
991     assert(isValidBaseClass(RD, dyn_cast<TypedValueRegion>(Super), IsVirtual));
992     (void)&isValidBaseClass;
993 
994     if (IsVirtual) {
995       // Virtual base regions should not be layered, since the layout rules
996       // are different.
997       while (const CXXBaseObjectRegion *Base =
998                dyn_cast<CXXBaseObjectRegion>(Super)) {
999         Super = Base->getSuperRegion();
1000       }
1001       assert(Super && !isa<MemSpaceRegion>(Super));
1002     }
1003   }
1004 
1005   return getSubRegion<CXXBaseObjectRegion>(RD, IsVirtual, Super);
1006 }
1007 
1008 const CXXThisRegion*
1009 MemRegionManager::getCXXThisRegion(QualType thisPointerTy,
1010                                    const LocationContext *LC) {
1011   const PointerType *PT = thisPointerTy->getAs<PointerType>();
1012   assert(PT);
1013   // Inside the body of the operator() of a lambda a this expr might refer to an
1014   // object in one of the parent location contexts.
1015   const auto *D = dyn_cast<CXXMethodDecl>(LC->getDecl());
1016   // FIXME: when operator() of lambda is analyzed as a top level function and
1017   // 'this' refers to a this to the enclosing scope, there is no right region to
1018   // return.
1019   while (!LC->inTopFrame() &&
1020          (!D || D->isStatic() ||
1021           PT != D->getThisType(getContext())->getAs<PointerType>())) {
1022     LC = LC->getParent();
1023     D = dyn_cast<CXXMethodDecl>(LC->getDecl());
1024   }
1025   const StackFrameContext *STC = LC->getCurrentStackFrame();
1026   assert(STC);
1027   return getSubRegion<CXXThisRegion>(PT, getStackArgumentsRegion(STC));
1028 }
1029 
1030 const AllocaRegion*
1031 MemRegionManager::getAllocaRegion(const Expr *E, unsigned cnt,
1032                                   const LocationContext *LC) {
1033   const StackFrameContext *STC = LC->getCurrentStackFrame();
1034   assert(STC);
1035   return getSubRegion<AllocaRegion>(E, cnt, getStackLocalsRegion(STC));
1036 }
1037 
1038 const MemSpaceRegion *MemRegion::getMemorySpace() const {
1039   const MemRegion *R = this;
1040   const SubRegion* SR = dyn_cast<SubRegion>(this);
1041 
1042   while (SR) {
1043     R = SR->getSuperRegion();
1044     SR = dyn_cast<SubRegion>(R);
1045   }
1046 
1047   return dyn_cast<MemSpaceRegion>(R);
1048 }
1049 
1050 bool MemRegion::hasStackStorage() const {
1051   return isa<StackSpaceRegion>(getMemorySpace());
1052 }
1053 
1054 bool MemRegion::hasStackNonParametersStorage() const {
1055   return isa<StackLocalsSpaceRegion>(getMemorySpace());
1056 }
1057 
1058 bool MemRegion::hasStackParametersStorage() const {
1059   return isa<StackArgumentsSpaceRegion>(getMemorySpace());
1060 }
1061 
1062 bool MemRegion::hasGlobalsOrParametersStorage() const {
1063   const MemSpaceRegion *MS = getMemorySpace();
1064   return isa<StackArgumentsSpaceRegion>(MS) ||
1065          isa<GlobalsSpaceRegion>(MS);
1066 }
1067 
1068 // getBaseRegion strips away all elements and fields, and get the base region
1069 // of them.
1070 const MemRegion *MemRegion::getBaseRegion() const {
1071   const MemRegion *R = this;
1072   while (true) {
1073     switch (R->getKind()) {
1074       case MemRegion::ElementRegionKind:
1075       case MemRegion::FieldRegionKind:
1076       case MemRegion::ObjCIvarRegionKind:
1077       case MemRegion::CXXBaseObjectRegionKind:
1078         R = cast<SubRegion>(R)->getSuperRegion();
1079         continue;
1080       default:
1081         break;
1082     }
1083     break;
1084   }
1085   return R;
1086 }
1087 
1088 bool MemRegion::isSubRegionOf(const MemRegion *R) const {
1089   return false;
1090 }
1091 
1092 //===----------------------------------------------------------------------===//
1093 // View handling.
1094 //===----------------------------------------------------------------------===//
1095 
1096 const MemRegion *MemRegion::StripCasts(bool StripBaseCasts) const {
1097   const MemRegion *R = this;
1098   while (true) {
1099     switch (R->getKind()) {
1100     case ElementRegionKind: {
1101       const ElementRegion *ER = cast<ElementRegion>(R);
1102       if (!ER->getIndex().isZeroConstant())
1103         return R;
1104       R = ER->getSuperRegion();
1105       break;
1106     }
1107     case CXXBaseObjectRegionKind:
1108       if (!StripBaseCasts)
1109         return R;
1110       R = cast<CXXBaseObjectRegion>(R)->getSuperRegion();
1111       break;
1112     default:
1113       return R;
1114     }
1115   }
1116 }
1117 
1118 const SymbolicRegion *MemRegion::getSymbolicBase() const {
1119   const SubRegion *SubR = dyn_cast<SubRegion>(this);
1120 
1121   while (SubR) {
1122     if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(SubR))
1123       return SymR;
1124     SubR = dyn_cast<SubRegion>(SubR->getSuperRegion());
1125   }
1126   return nullptr;
1127 }
1128 
1129 RegionRawOffset ElementRegion::getAsArrayOffset() const {
1130   CharUnits offset = CharUnits::Zero();
1131   const ElementRegion *ER = this;
1132   const MemRegion *superR = nullptr;
1133   ASTContext &C = getContext();
1134 
1135   // FIXME: Handle multi-dimensional arrays.
1136 
1137   while (ER) {
1138     superR = ER->getSuperRegion();
1139 
1140     // FIXME: generalize to symbolic offsets.
1141     SVal index = ER->getIndex();
1142     if (Optional<nonloc::ConcreteInt> CI = index.getAs<nonloc::ConcreteInt>()) {
1143       // Update the offset.
1144       int64_t i = CI->getValue().getSExtValue();
1145 
1146       if (i != 0) {
1147         QualType elemType = ER->getElementType();
1148 
1149         // If we are pointing to an incomplete type, go no further.
1150         if (elemType->isIncompleteType()) {
1151           superR = ER;
1152           break;
1153         }
1154 
1155         CharUnits size = C.getTypeSizeInChars(elemType);
1156         offset += (i * size);
1157       }
1158 
1159       // Go to the next ElementRegion (if any).
1160       ER = dyn_cast<ElementRegion>(superR);
1161       continue;
1162     }
1163 
1164     return nullptr;
1165   }
1166 
1167   assert(superR && "super region cannot be NULL");
1168   return RegionRawOffset(superR, offset);
1169 }
1170 
1171 
1172 /// Returns true if \p Base is an immediate base class of \p Child
1173 static bool isImmediateBase(const CXXRecordDecl *Child,
1174                             const CXXRecordDecl *Base) {
1175   assert(Child && "Child must not be null");
1176   // Note that we do NOT canonicalize the base class here, because
1177   // ASTRecordLayout doesn't either. If that leads us down the wrong path,
1178   // so be it; at least we won't crash.
1179   for (const auto &I : Child->bases()) {
1180     if (I.getType()->getAsCXXRecordDecl() == Base)
1181       return true;
1182   }
1183 
1184   return false;
1185 }
1186 
1187 RegionOffset MemRegion::getAsOffset() const {
1188   const MemRegion *R = this;
1189   const MemRegion *SymbolicOffsetBase = nullptr;
1190   int64_t Offset = 0;
1191 
1192   while (1) {
1193     switch (R->getKind()) {
1194     case CodeSpaceRegionKind:
1195     case StackLocalsSpaceRegionKind:
1196     case StackArgumentsSpaceRegionKind:
1197     case HeapSpaceRegionKind:
1198     case UnknownSpaceRegionKind:
1199     case StaticGlobalSpaceRegionKind:
1200     case GlobalInternalSpaceRegionKind:
1201     case GlobalSystemSpaceRegionKind:
1202     case GlobalImmutableSpaceRegionKind:
1203       // Stores can bind directly to a region space to set a default value.
1204       assert(Offset == 0 && !SymbolicOffsetBase);
1205       goto Finish;
1206 
1207     case FunctionCodeRegionKind:
1208     case BlockCodeRegionKind:
1209     case BlockDataRegionKind:
1210       // These will never have bindings, but may end up having values requested
1211       // if the user does some strange casting.
1212       if (Offset != 0)
1213         SymbolicOffsetBase = R;
1214       goto Finish;
1215 
1216     case SymbolicRegionKind:
1217     case AllocaRegionKind:
1218     case CompoundLiteralRegionKind:
1219     case CXXThisRegionKind:
1220     case StringRegionKind:
1221     case ObjCStringRegionKind:
1222     case VarRegionKind:
1223     case CXXTempObjectRegionKind:
1224       // Usual base regions.
1225       goto Finish;
1226 
1227     case ObjCIvarRegionKind:
1228       // This is a little strange, but it's a compromise between
1229       // ObjCIvarRegions having unknown compile-time offsets (when using the
1230       // non-fragile runtime) and yet still being distinct, non-overlapping
1231       // regions. Thus we treat them as "like" base regions for the purposes
1232       // of computing offsets.
1233       goto Finish;
1234 
1235     case CXXBaseObjectRegionKind: {
1236       const CXXBaseObjectRegion *BOR = cast<CXXBaseObjectRegion>(R);
1237       R = BOR->getSuperRegion();
1238 
1239       QualType Ty;
1240       bool RootIsSymbolic = false;
1241       if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) {
1242         Ty = TVR->getDesugaredValueType(getContext());
1243       } else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
1244         // If our base region is symbolic, we don't know what type it really is.
1245         // Pretend the type of the symbol is the true dynamic type.
1246         // (This will at least be self-consistent for the life of the symbol.)
1247         Ty = SR->getSymbol()->getType()->getPointeeType();
1248         RootIsSymbolic = true;
1249       }
1250 
1251       const CXXRecordDecl *Child = Ty->getAsCXXRecordDecl();
1252       if (!Child) {
1253         // We cannot compute the offset of the base class.
1254         SymbolicOffsetBase = R;
1255       } else {
1256         if (RootIsSymbolic) {
1257           // Base layers on symbolic regions may not be type-correct.
1258           // Double-check the inheritance here, and revert to a symbolic offset
1259           // if it's invalid (e.g. due to a reinterpret_cast).
1260           if (BOR->isVirtual()) {
1261             if (!Child->isVirtuallyDerivedFrom(BOR->getDecl()))
1262               SymbolicOffsetBase = R;
1263           } else {
1264             if (!isImmediateBase(Child, BOR->getDecl()))
1265               SymbolicOffsetBase = R;
1266           }
1267         }
1268       }
1269 
1270       // Don't bother calculating precise offsets if we already have a
1271       // symbolic offset somewhere in the chain.
1272       if (SymbolicOffsetBase)
1273         continue;
1274 
1275       CharUnits BaseOffset;
1276       const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Child);
1277       if (BOR->isVirtual())
1278         BaseOffset = Layout.getVBaseClassOffset(BOR->getDecl());
1279       else
1280         BaseOffset = Layout.getBaseClassOffset(BOR->getDecl());
1281 
1282       // The base offset is in chars, not in bits.
1283       Offset += BaseOffset.getQuantity() * getContext().getCharWidth();
1284       break;
1285     }
1286     case ElementRegionKind: {
1287       const ElementRegion *ER = cast<ElementRegion>(R);
1288       R = ER->getSuperRegion();
1289 
1290       QualType EleTy = ER->getValueType();
1291       if (EleTy->isIncompleteType()) {
1292         // We cannot compute the offset of the base class.
1293         SymbolicOffsetBase = R;
1294         continue;
1295       }
1296 
1297       SVal Index = ER->getIndex();
1298       if (Optional<nonloc::ConcreteInt> CI =
1299               Index.getAs<nonloc::ConcreteInt>()) {
1300         // Don't bother calculating precise offsets if we already have a
1301         // symbolic offset somewhere in the chain.
1302         if (SymbolicOffsetBase)
1303           continue;
1304 
1305         int64_t i = CI->getValue().getSExtValue();
1306         // This type size is in bits.
1307         Offset += i * getContext().getTypeSize(EleTy);
1308       } else {
1309         // We cannot compute offset for non-concrete index.
1310         SymbolicOffsetBase = R;
1311       }
1312       break;
1313     }
1314     case FieldRegionKind: {
1315       const FieldRegion *FR = cast<FieldRegion>(R);
1316       R = FR->getSuperRegion();
1317 
1318       const RecordDecl *RD = FR->getDecl()->getParent();
1319       if (RD->isUnion() || !RD->isCompleteDefinition()) {
1320         // We cannot compute offset for incomplete type.
1321         // For unions, we could treat everything as offset 0, but we'd rather
1322         // treat each field as a symbolic offset so they aren't stored on top
1323         // of each other, since we depend on things in typed regions actually
1324         // matching their types.
1325         SymbolicOffsetBase = R;
1326       }
1327 
1328       // Don't bother calculating precise offsets if we already have a
1329       // symbolic offset somewhere in the chain.
1330       if (SymbolicOffsetBase)
1331         continue;
1332 
1333       // Get the field number.
1334       unsigned idx = 0;
1335       for (RecordDecl::field_iterator FI = RD->field_begin(),
1336              FE = RD->field_end(); FI != FE; ++FI, ++idx) {
1337         if (FR->getDecl() == *FI)
1338           break;
1339       }
1340       const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1341       // This is offset in bits.
1342       Offset += Layout.getFieldOffset(idx);
1343       break;
1344     }
1345     }
1346   }
1347 
1348  Finish:
1349   if (SymbolicOffsetBase)
1350     return RegionOffset(SymbolicOffsetBase, RegionOffset::Symbolic);
1351   return RegionOffset(R, Offset);
1352 }
1353 
1354 //===----------------------------------------------------------------------===//
1355 // BlockDataRegion
1356 //===----------------------------------------------------------------------===//
1357 
1358 std::pair<const VarRegion *, const VarRegion *>
1359 BlockDataRegion::getCaptureRegions(const VarDecl *VD) {
1360   MemRegionManager &MemMgr = *getMemRegionManager();
1361   const VarRegion *VR = nullptr;
1362   const VarRegion *OriginalVR = nullptr;
1363 
1364   if (!VD->hasAttr<BlocksAttr>() && VD->hasLocalStorage()) {
1365     VR = MemMgr.getVarRegion(VD, this);
1366     OriginalVR = MemMgr.getVarRegion(VD, LC);
1367   }
1368   else {
1369     if (LC) {
1370       VR = MemMgr.getVarRegion(VD, LC);
1371       OriginalVR = VR;
1372     }
1373     else {
1374       VR = MemMgr.getVarRegion(VD, MemMgr.getUnknownRegion());
1375       OriginalVR = MemMgr.getVarRegion(VD, LC);
1376     }
1377   }
1378   return std::make_pair(VR, OriginalVR);
1379 }
1380 
1381 void BlockDataRegion::LazyInitializeReferencedVars() {
1382   if (ReferencedVars)
1383     return;
1384 
1385   AnalysisDeclContext *AC = getCodeRegion()->getAnalysisDeclContext();
1386   const auto &ReferencedBlockVars = AC->getReferencedBlockVars(BC->getDecl());
1387   auto NumBlockVars =
1388       std::distance(ReferencedBlockVars.begin(), ReferencedBlockVars.end());
1389 
1390   if (NumBlockVars == 0) {
1391     ReferencedVars = (void*) 0x1;
1392     return;
1393   }
1394 
1395   MemRegionManager &MemMgr = *getMemRegionManager();
1396   llvm::BumpPtrAllocator &A = MemMgr.getAllocator();
1397   BumpVectorContext BC(A);
1398 
1399   typedef BumpVector<const MemRegion*> VarVec;
1400   VarVec *BV = A.Allocate<VarVec>();
1401   new (BV) VarVec(BC, NumBlockVars);
1402   VarVec *BVOriginal = A.Allocate<VarVec>();
1403   new (BVOriginal) VarVec(BC, NumBlockVars);
1404 
1405   for (const VarDecl *VD : ReferencedBlockVars) {
1406     const VarRegion *VR = nullptr;
1407     const VarRegion *OriginalVR = nullptr;
1408     std::tie(VR, OriginalVR) = getCaptureRegions(VD);
1409     assert(VR);
1410     assert(OriginalVR);
1411     BV->push_back(VR, BC);
1412     BVOriginal->push_back(OriginalVR, BC);
1413   }
1414 
1415   ReferencedVars = BV;
1416   OriginalVars = BVOriginal;
1417 }
1418 
1419 BlockDataRegion::referenced_vars_iterator
1420 BlockDataRegion::referenced_vars_begin() const {
1421   const_cast<BlockDataRegion*>(this)->LazyInitializeReferencedVars();
1422 
1423   BumpVector<const MemRegion*> *Vec =
1424     static_cast<BumpVector<const MemRegion*>*>(ReferencedVars);
1425 
1426   if (Vec == (void*) 0x1)
1427     return BlockDataRegion::referenced_vars_iterator(nullptr, nullptr);
1428 
1429   BumpVector<const MemRegion*> *VecOriginal =
1430     static_cast<BumpVector<const MemRegion*>*>(OriginalVars);
1431 
1432   return BlockDataRegion::referenced_vars_iterator(Vec->begin(),
1433                                                    VecOriginal->begin());
1434 }
1435 
1436 BlockDataRegion::referenced_vars_iterator
1437 BlockDataRegion::referenced_vars_end() const {
1438   const_cast<BlockDataRegion*>(this)->LazyInitializeReferencedVars();
1439 
1440   BumpVector<const MemRegion*> *Vec =
1441     static_cast<BumpVector<const MemRegion*>*>(ReferencedVars);
1442 
1443   if (Vec == (void*) 0x1)
1444     return BlockDataRegion::referenced_vars_iterator(nullptr, nullptr);
1445 
1446   BumpVector<const MemRegion*> *VecOriginal =
1447     static_cast<BumpVector<const MemRegion*>*>(OriginalVars);
1448 
1449   return BlockDataRegion::referenced_vars_iterator(Vec->end(),
1450                                                    VecOriginal->end());
1451 }
1452 
1453 const VarRegion *BlockDataRegion::getOriginalRegion(const VarRegion *R) const {
1454   for (referenced_vars_iterator I = referenced_vars_begin(),
1455                                 E = referenced_vars_end();
1456        I != E; ++I) {
1457     if (I.getCapturedRegion() == R)
1458       return I.getOriginalRegion();
1459   }
1460   return nullptr;
1461 }
1462 
1463 //===----------------------------------------------------------------------===//
1464 // RegionAndSymbolInvalidationTraits
1465 //===----------------------------------------------------------------------===//
1466 
1467 void RegionAndSymbolInvalidationTraits::setTrait(SymbolRef Sym,
1468                                                  InvalidationKinds IK) {
1469   SymTraitsMap[Sym] |= IK;
1470 }
1471 
1472 void RegionAndSymbolInvalidationTraits::setTrait(const MemRegion *MR,
1473                                                  InvalidationKinds IK) {
1474   assert(MR);
1475   if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1476     setTrait(SR->getSymbol(), IK);
1477   else
1478     MRTraitsMap[MR] |= IK;
1479 }
1480 
1481 bool RegionAndSymbolInvalidationTraits::hasTrait(SymbolRef Sym,
1482                                                  InvalidationKinds IK) const {
1483   const_symbol_iterator I = SymTraitsMap.find(Sym);
1484   if (I != SymTraitsMap.end())
1485     return I->second & IK;
1486 
1487   return false;
1488 }
1489 
1490 bool RegionAndSymbolInvalidationTraits::hasTrait(const MemRegion *MR,
1491                                                  InvalidationKinds IK) const {
1492   if (!MR)
1493     return false;
1494 
1495   if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1496     return hasTrait(SR->getSymbol(), IK);
1497 
1498   const_region_iterator I = MRTraitsMap.find(MR);
1499   if (I != MRTraitsMap.end())
1500     return I->second & IK;
1501 
1502   return false;
1503 }
1504