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, typename SuperTy, typename Arg1Ty>
35 RegionTy* MemRegionManager::getSubRegion(const Arg1Ty arg1,
36                                          const SuperTy *superRegion) {
37   llvm::FoldingSetNodeID ID;
38   RegionTy::ProfileRegion(ID, arg1, superRegion);
39   void *InsertPos;
40   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
41                                                                    InsertPos));
42 
43   if (!R) {
44     R = A.Allocate<RegionTy>();
45     new (R) RegionTy(arg1, superRegion);
46     Regions.InsertNode(R, InsertPos);
47   }
48 
49   return R;
50 }
51 
52 template <typename RegionTy, typename SuperTy, typename Arg1Ty, typename Arg2Ty>
53 RegionTy* MemRegionManager::getSubRegion(const Arg1Ty arg1, const Arg2Ty arg2,
54                                          const SuperTy *superRegion) {
55   llvm::FoldingSetNodeID ID;
56   RegionTy::ProfileRegion(ID, arg1, arg2, superRegion);
57   void *InsertPos;
58   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
59                                                                    InsertPos));
60 
61   if (!R) {
62     R = A.Allocate<RegionTy>();
63     new (R) RegionTy(arg1, arg2, superRegion);
64     Regions.InsertNode(R, InsertPos);
65   }
66 
67   return R;
68 }
69 
70 template <typename RegionTy, typename SuperTy,
71           typename Arg1Ty, typename Arg2Ty, typename Arg3Ty>
72 RegionTy* MemRegionManager::getSubRegion(const Arg1Ty arg1, const Arg2Ty arg2,
73                                          const Arg3Ty arg3,
74                                          const SuperTy *superRegion) {
75   llvm::FoldingSetNodeID ID;
76   RegionTy::ProfileRegion(ID, arg1, arg2, arg3, superRegion);
77   void *InsertPos;
78   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
79                                                                    InsertPos));
80 
81   if (!R) {
82     R = A.Allocate<RegionTy>();
83     new (R) RegionTy(arg1, arg2, arg3, superRegion);
84     Regions.InsertNode(R, InsertPos);
85   }
86 
87   return R;
88 }
89 
90 //===----------------------------------------------------------------------===//
91 // Object destruction.
92 //===----------------------------------------------------------------------===//
93 
94 MemRegion::~MemRegion() {}
95 
96 MemRegionManager::~MemRegionManager() {
97   // All regions and their data are BumpPtrAllocated.  No need to call
98   // their destructors.
99 }
100 
101 //===----------------------------------------------------------------------===//
102 // Basic methods.
103 //===----------------------------------------------------------------------===//
104 
105 bool SubRegion::isSubRegionOf(const MemRegion* R) const {
106   const MemRegion* r = getSuperRegion();
107   while (r != nullptr) {
108     if (r == R)
109       return true;
110     if (const SubRegion* sr = dyn_cast<SubRegion>(r))
111       r = sr->getSuperRegion();
112     else
113       break;
114   }
115   return false;
116 }
117 
118 MemRegionManager* SubRegion::getMemRegionManager() const {
119   const SubRegion* r = this;
120   do {
121     const MemRegion *superRegion = r->getSuperRegion();
122     if (const SubRegion *sr = dyn_cast<SubRegion>(superRegion)) {
123       r = sr;
124       continue;
125     }
126     return superRegion->getMemRegionManager();
127   } while (1);
128 }
129 
130 const StackFrameContext *VarRegion::getStackFrame() const {
131   const StackSpaceRegion *SSR = dyn_cast<StackSpaceRegion>(getMemorySpace());
132   return SSR ? SSR->getStackFrame() : nullptr;
133 }
134 
135 //===----------------------------------------------------------------------===//
136 // Region extents.
137 //===----------------------------------------------------------------------===//
138 
139 DefinedOrUnknownSVal TypedValueRegion::getExtent(SValBuilder &svalBuilder) const {
140   ASTContext &Ctx = svalBuilder.getContext();
141   QualType T = getDesugaredValueType(Ctx);
142 
143   if (isa<VariableArrayType>(T))
144     return nonloc::SymbolVal(svalBuilder.getSymbolManager().getExtentSymbol(this));
145   if (T->isIncompleteType())
146     return UnknownVal();
147 
148   CharUnits size = Ctx.getTypeSizeInChars(T);
149   QualType sizeTy = svalBuilder.getArrayIndexType();
150   return svalBuilder.makeIntVal(size.getQuantity(), sizeTy);
151 }
152 
153 DefinedOrUnknownSVal FieldRegion::getExtent(SValBuilder &svalBuilder) const {
154   // Force callers to deal with bitfields explicitly.
155   if (getDecl()->isBitField())
156     return UnknownVal();
157 
158   DefinedOrUnknownSVal Extent = DeclRegion::getExtent(svalBuilder);
159 
160   // A zero-length array at the end of a struct often stands for dynamically-
161   // allocated extra memory.
162   if (Extent.isZeroConstant()) {
163     QualType T = getDesugaredValueType(svalBuilder.getContext());
164 
165     if (isa<ConstantArrayType>(T))
166       return UnknownVal();
167   }
168 
169   return Extent;
170 }
171 
172 DefinedOrUnknownSVal AllocaRegion::getExtent(SValBuilder &svalBuilder) const {
173   return nonloc::SymbolVal(svalBuilder.getSymbolManager().getExtentSymbol(this));
174 }
175 
176 DefinedOrUnknownSVal SymbolicRegion::getExtent(SValBuilder &svalBuilder) const {
177   return nonloc::SymbolVal(svalBuilder.getSymbolManager().getExtentSymbol(this));
178 }
179 
180 DefinedOrUnknownSVal StringRegion::getExtent(SValBuilder &svalBuilder) const {
181   return svalBuilder.makeIntVal(getStringLiteral()->getByteLength()+1,
182                                 svalBuilder.getArrayIndexType());
183 }
184 
185 ObjCIvarRegion::ObjCIvarRegion(const ObjCIvarDecl *ivd, const SubRegion *sReg)
186     : DeclRegion(ivd, sReg, ObjCIvarRegionKind) {}
187 
188 const ObjCIvarDecl *ObjCIvarRegion::getDecl() const {
189   return cast<ObjCIvarDecl>(D);
190 }
191 
192 QualType ObjCIvarRegion::getValueType() const {
193   return getDecl()->getType();
194 }
195 
196 QualType CXXBaseObjectRegion::getValueType() const {
197   return QualType(getDecl()->getTypeForDecl(), 0);
198 }
199 
200 //===----------------------------------------------------------------------===//
201 // FoldingSet profiling.
202 //===----------------------------------------------------------------------===//
203 
204 void MemSpaceRegion::Profile(llvm::FoldingSetNodeID &ID) const {
205   ID.AddInteger(static_cast<unsigned>(getKind()));
206 }
207 
208 void StackSpaceRegion::Profile(llvm::FoldingSetNodeID &ID) const {
209   ID.AddInteger(static_cast<unsigned>(getKind()));
210   ID.AddPointer(getStackFrame());
211 }
212 
213 void StaticGlobalSpaceRegion::Profile(llvm::FoldingSetNodeID &ID) const {
214   ID.AddInteger(static_cast<unsigned>(getKind()));
215   ID.AddPointer(getCodeRegion());
216 }
217 
218 void StringRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
219                                  const StringLiteral* Str,
220                                  const MemRegion* superRegion) {
221   ID.AddInteger(static_cast<unsigned>(StringRegionKind));
222   ID.AddPointer(Str);
223   ID.AddPointer(superRegion);
224 }
225 
226 void ObjCStringRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
227                                      const ObjCStringLiteral* Str,
228                                      const MemRegion* superRegion) {
229   ID.AddInteger(static_cast<unsigned>(ObjCStringRegionKind));
230   ID.AddPointer(Str);
231   ID.AddPointer(superRegion);
232 }
233 
234 void AllocaRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
235                                  const Expr *Ex, unsigned cnt,
236                                  const MemRegion *superRegion) {
237   ID.AddInteger(static_cast<unsigned>(AllocaRegionKind));
238   ID.AddPointer(Ex);
239   ID.AddInteger(cnt);
240   ID.AddPointer(superRegion);
241 }
242 
243 void AllocaRegion::Profile(llvm::FoldingSetNodeID& ID) const {
244   ProfileRegion(ID, Ex, Cnt, superRegion);
245 }
246 
247 void CompoundLiteralRegion::Profile(llvm::FoldingSetNodeID& ID) const {
248   CompoundLiteralRegion::ProfileRegion(ID, CL, superRegion);
249 }
250 
251 void CompoundLiteralRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
252                                           const CompoundLiteralExpr *CL,
253                                           const MemRegion* superRegion) {
254   ID.AddInteger(static_cast<unsigned>(CompoundLiteralRegionKind));
255   ID.AddPointer(CL);
256   ID.AddPointer(superRegion);
257 }
258 
259 void CXXThisRegion::ProfileRegion(llvm::FoldingSetNodeID &ID,
260                                   const PointerType *PT,
261                                   const MemRegion *sRegion) {
262   ID.AddInteger(static_cast<unsigned>(CXXThisRegionKind));
263   ID.AddPointer(PT);
264   ID.AddPointer(sRegion);
265 }
266 
267 void CXXThisRegion::Profile(llvm::FoldingSetNodeID &ID) const {
268   CXXThisRegion::ProfileRegion(ID, ThisPointerTy, superRegion);
269 }
270 
271 void ObjCIvarRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
272                                    const ObjCIvarDecl *ivd,
273                                    const MemRegion* superRegion) {
274   DeclRegion::ProfileRegion(ID, ivd, superRegion, ObjCIvarRegionKind);
275 }
276 
277 void DeclRegion::ProfileRegion(llvm::FoldingSetNodeID& ID, const Decl *D,
278                                const MemRegion* superRegion, Kind k) {
279   ID.AddInteger(static_cast<unsigned>(k));
280   ID.AddPointer(D);
281   ID.AddPointer(superRegion);
282 }
283 
284 void DeclRegion::Profile(llvm::FoldingSetNodeID& ID) const {
285   DeclRegion::ProfileRegion(ID, D, superRegion, getKind());
286 }
287 
288 void VarRegion::Profile(llvm::FoldingSetNodeID &ID) const {
289   VarRegion::ProfileRegion(ID, getDecl(), superRegion);
290 }
291 
292 void SymbolicRegion::ProfileRegion(llvm::FoldingSetNodeID& ID, SymbolRef sym,
293                                    const MemRegion *sreg) {
294   ID.AddInteger(static_cast<unsigned>(MemRegion::SymbolicRegionKind));
295   ID.Add(sym);
296   ID.AddPointer(sreg);
297 }
298 
299 void SymbolicRegion::Profile(llvm::FoldingSetNodeID& ID) const {
300   SymbolicRegion::ProfileRegion(ID, sym, getSuperRegion());
301 }
302 
303 void ElementRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
304                                   QualType ElementType, SVal Idx,
305                                   const MemRegion* superRegion) {
306   ID.AddInteger(MemRegion::ElementRegionKind);
307   ID.Add(ElementType);
308   ID.AddPointer(superRegion);
309   Idx.Profile(ID);
310 }
311 
312 void ElementRegion::Profile(llvm::FoldingSetNodeID& ID) const {
313   ElementRegion::ProfileRegion(ID, ElementType, Index, superRegion);
314 }
315 
316 void FunctionCodeRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
317                                        const NamedDecl *FD,
318                                        const MemRegion*) {
319   ID.AddInteger(MemRegion::FunctionCodeRegionKind);
320   ID.AddPointer(FD);
321 }
322 
323 void FunctionCodeRegion::Profile(llvm::FoldingSetNodeID& ID) const {
324   FunctionCodeRegion::ProfileRegion(ID, FD, superRegion);
325 }
326 
327 void BlockCodeRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
328                                     const BlockDecl *BD, CanQualType,
329                                     const AnalysisDeclContext *AC,
330                                     const MemRegion*) {
331   ID.AddInteger(MemRegion::BlockCodeRegionKind);
332   ID.AddPointer(BD);
333 }
334 
335 void BlockCodeRegion::Profile(llvm::FoldingSetNodeID& ID) const {
336   BlockCodeRegion::ProfileRegion(ID, BD, locTy, AC, superRegion);
337 }
338 
339 void BlockDataRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
340                                     const BlockCodeRegion *BC,
341                                     const LocationContext *LC,
342                                     unsigned BlkCount,
343                                     const MemRegion *sReg) {
344   ID.AddInteger(MemRegion::BlockDataRegionKind);
345   ID.AddPointer(BC);
346   ID.AddPointer(LC);
347   ID.AddInteger(BlkCount);
348   ID.AddPointer(sReg);
349 }
350 
351 void BlockDataRegion::Profile(llvm::FoldingSetNodeID& ID) const {
352   BlockDataRegion::ProfileRegion(ID, BC, LC, BlockCount, getSuperRegion());
353 }
354 
355 void CXXTempObjectRegion::ProfileRegion(llvm::FoldingSetNodeID &ID,
356                                         Expr const *Ex,
357                                         const MemRegion *sReg) {
358   ID.AddPointer(Ex);
359   ID.AddPointer(sReg);
360 }
361 
362 void CXXTempObjectRegion::Profile(llvm::FoldingSetNodeID &ID) const {
363   ProfileRegion(ID, Ex, getSuperRegion());
364 }
365 
366 void CXXBaseObjectRegion::ProfileRegion(llvm::FoldingSetNodeID &ID,
367                                         const CXXRecordDecl *RD,
368                                         bool IsVirtual,
369                                         const MemRegion *SReg) {
370   ID.AddPointer(RD);
371   ID.AddBoolean(IsVirtual);
372   ID.AddPointer(SReg);
373 }
374 
375 void CXXBaseObjectRegion::Profile(llvm::FoldingSetNodeID &ID) const {
376   ProfileRegion(ID, getDecl(), isVirtual(), superRegion);
377 }
378 
379 //===----------------------------------------------------------------------===//
380 // Region anchors.
381 //===----------------------------------------------------------------------===//
382 
383 void GlobalsSpaceRegion::anchor() { }
384 void NonStaticGlobalSpaceRegion::anchor() { }
385 void StackSpaceRegion::anchor() { }
386 void TypedRegion::anchor() { }
387 void TypedValueRegion::anchor() { }
388 void CodeTextRegion::anchor() { }
389 void SubRegion::anchor() { }
390 
391 //===----------------------------------------------------------------------===//
392 // Region pretty-printing.
393 //===----------------------------------------------------------------------===//
394 
395 LLVM_DUMP_METHOD void MemRegion::dump() const {
396   dumpToStream(llvm::errs());
397 }
398 
399 std::string MemRegion::getString() const {
400   std::string s;
401   llvm::raw_string_ostream os(s);
402   dumpToStream(os);
403   return os.str();
404 }
405 
406 void MemRegion::dumpToStream(raw_ostream &os) const {
407   os << "<Unknown Region>";
408 }
409 
410 void AllocaRegion::dumpToStream(raw_ostream &os) const {
411   os << "alloca{" << static_cast<const void*>(Ex) << ',' << Cnt << '}';
412 }
413 
414 void FunctionCodeRegion::dumpToStream(raw_ostream &os) const {
415   os << "code{" << getDecl()->getDeclName().getAsString() << '}';
416 }
417 
418 void BlockCodeRegion::dumpToStream(raw_ostream &os) const {
419   os << "block_code{" << static_cast<const void*>(this) << '}';
420 }
421 
422 void BlockDataRegion::dumpToStream(raw_ostream &os) const {
423   os << "block_data{" << BC;
424   os << "; ";
425   for (BlockDataRegion::referenced_vars_iterator
426          I = referenced_vars_begin(),
427          E = referenced_vars_end(); I != E; ++I)
428     os << "(" << I.getCapturedRegion() << "," <<
429                  I.getOriginalRegion() << ") ";
430   os << '}';
431 }
432 
433 void CompoundLiteralRegion::dumpToStream(raw_ostream &os) const {
434   // FIXME: More elaborate pretty-printing.
435   os << "{ " << static_cast<const void*>(CL) <<  " }";
436 }
437 
438 void CXXTempObjectRegion::dumpToStream(raw_ostream &os) const {
439   os << "temp_object{" << getValueType().getAsString() << ','
440      << static_cast<const void*>(Ex) << '}';
441 }
442 
443 void CXXBaseObjectRegion::dumpToStream(raw_ostream &os) const {
444   os << "base{" << superRegion << ',' << getDecl()->getName() << '}';
445 }
446 
447 void CXXThisRegion::dumpToStream(raw_ostream &os) const {
448   os << "this";
449 }
450 
451 void ElementRegion::dumpToStream(raw_ostream &os) const {
452   os << "element{" << superRegion << ','
453      << Index << ',' << getElementType().getAsString() << '}';
454 }
455 
456 void FieldRegion::dumpToStream(raw_ostream &os) const {
457   os << superRegion << "->" << *getDecl();
458 }
459 
460 void ObjCIvarRegion::dumpToStream(raw_ostream &os) const {
461   os << "ivar{" << superRegion << ',' << *getDecl() << '}';
462 }
463 
464 void StringRegion::dumpToStream(raw_ostream &os) const {
465   assert(Str != nullptr && "Expecting non-null StringLiteral");
466   Str->printPretty(os, nullptr, PrintingPolicy(getContext().getLangOpts()));
467 }
468 
469 void ObjCStringRegion::dumpToStream(raw_ostream &os) const {
470   assert(Str != nullptr && "Expecting non-null ObjCStringLiteral");
471   Str->printPretty(os, nullptr, PrintingPolicy(getContext().getLangOpts()));
472 }
473 
474 void SymbolicRegion::dumpToStream(raw_ostream &os) const {
475   os << "SymRegion{" << sym << '}';
476 }
477 
478 void VarRegion::dumpToStream(raw_ostream &os) const {
479   os << *cast<VarDecl>(D);
480 }
481 
482 LLVM_DUMP_METHOD void RegionRawOffset::dump() const {
483   dumpToStream(llvm::errs());
484 }
485 
486 void RegionRawOffset::dumpToStream(raw_ostream &os) const {
487   os << "raw_offset{" << getRegion() << ',' << getOffset().getQuantity() << '}';
488 }
489 
490 void CodeSpaceRegion::dumpToStream(raw_ostream &os) const {
491   os << "CodeSpaceRegion";
492 }
493 
494 void StaticGlobalSpaceRegion::dumpToStream(raw_ostream &os) const {
495   os << "StaticGlobalsMemSpace{" << CR << '}';
496 }
497 
498 void GlobalInternalSpaceRegion::dumpToStream(raw_ostream &os) const {
499   os << "GlobalInternalSpaceRegion";
500 }
501 
502 void GlobalSystemSpaceRegion::dumpToStream(raw_ostream &os) const {
503   os << "GlobalSystemSpaceRegion";
504 }
505 
506 void GlobalImmutableSpaceRegion::dumpToStream(raw_ostream &os) const {
507   os << "GlobalImmutableSpaceRegion";
508 }
509 
510 void HeapSpaceRegion::dumpToStream(raw_ostream &os) const {
511   os << "HeapSpaceRegion";
512 }
513 
514 void UnknownSpaceRegion::dumpToStream(raw_ostream &os) const {
515   os << "UnknownSpaceRegion";
516 }
517 
518 void StackArgumentsSpaceRegion::dumpToStream(raw_ostream &os) const {
519   os << "StackArgumentsSpaceRegion";
520 }
521 
522 void StackLocalsSpaceRegion::dumpToStream(raw_ostream &os) const {
523   os << "StackLocalsSpaceRegion";
524 }
525 
526 bool MemRegion::canPrintPretty() const {
527   return canPrintPrettyAsExpr();
528 }
529 
530 bool MemRegion::canPrintPrettyAsExpr() const {
531   return false;
532 }
533 
534 void MemRegion::printPretty(raw_ostream &os) const {
535   assert(canPrintPretty() && "This region cannot be printed pretty.");
536   os << "'";
537   printPrettyAsExpr(os);
538   os << "'";
539 }
540 
541 void MemRegion::printPrettyAsExpr(raw_ostream &os) const {
542   llvm_unreachable("This region cannot be printed pretty.");
543 }
544 
545 bool VarRegion::canPrintPrettyAsExpr() const {
546   return true;
547 }
548 
549 void VarRegion::printPrettyAsExpr(raw_ostream &os) const {
550   os << getDecl()->getName();
551 }
552 
553 bool ObjCIvarRegion::canPrintPrettyAsExpr() const {
554   return true;
555 }
556 
557 void ObjCIvarRegion::printPrettyAsExpr(raw_ostream &os) const {
558   os << getDecl()->getName();
559 }
560 
561 bool FieldRegion::canPrintPretty() const {
562   return true;
563 }
564 
565 bool FieldRegion::canPrintPrettyAsExpr() const {
566   return superRegion->canPrintPrettyAsExpr();
567 }
568 
569 void FieldRegion::printPrettyAsExpr(raw_ostream &os) const {
570   assert(canPrintPrettyAsExpr());
571   superRegion->printPrettyAsExpr(os);
572   os << "." << getDecl()->getName();
573 }
574 
575 void FieldRegion::printPretty(raw_ostream &os) const {
576   if (canPrintPrettyAsExpr()) {
577     os << "\'";
578     printPrettyAsExpr(os);
579     os << "'";
580   } else {
581     os << "field " << "\'" << getDecl()->getName() << "'";
582   }
583 }
584 
585 bool CXXBaseObjectRegion::canPrintPrettyAsExpr() const {
586   return superRegion->canPrintPrettyAsExpr();
587 }
588 
589 void CXXBaseObjectRegion::printPrettyAsExpr(raw_ostream &os) const {
590   superRegion->printPrettyAsExpr(os);
591 }
592 
593 std::string MemRegion::getDescriptiveName(bool UseQuotes) const {
594   std::string VariableName;
595   std::string ArrayIndices;
596   const MemRegion *R = this;
597   SmallString<50> buf;
598   llvm::raw_svector_ostream os(buf);
599 
600   // Obtain array indices to add them to the variable name.
601   const ElementRegion *ER = nullptr;
602   while ((ER = R->getAs<ElementRegion>())) {
603     // Index is a ConcreteInt.
604     if (auto CI = ER->getIndex().getAs<nonloc::ConcreteInt>()) {
605       llvm::SmallString<2> Idx;
606       CI->getValue().toString(Idx);
607       ArrayIndices = (llvm::Twine("[") + Idx.str() + "]" + ArrayIndices).str();
608     }
609     // If not a ConcreteInt, try to obtain the variable
610     // name by calling 'getDescriptiveName' recursively.
611     else {
612       std::string Idx = ER->getDescriptiveName(false);
613       if (!Idx.empty()) {
614         ArrayIndices = (llvm::Twine("[") + Idx + "]" + ArrayIndices).str();
615       }
616     }
617     R = ER->getSuperRegion();
618   }
619 
620   // Get variable name.
621   if (R && R->canPrintPrettyAsExpr()) {
622     R->printPrettyAsExpr(os);
623     if (UseQuotes) {
624       return (llvm::Twine("'") + os.str() + ArrayIndices + "'").str();
625     } else {
626       return (llvm::Twine(os.str()) + ArrayIndices).str();
627     }
628   }
629 
630   return VariableName;
631 }
632 
633 SourceRange MemRegion::sourceRange() const {
634   const VarRegion *const VR = dyn_cast<VarRegion>(this->getBaseRegion());
635   const FieldRegion *const FR = dyn_cast<FieldRegion>(this);
636 
637   // Check for more specific regions first.
638   // FieldRegion
639   if (FR) {
640     return FR->getDecl()->getSourceRange();
641   }
642   // VarRegion
643   else if (VR) {
644     return VR->getDecl()->getSourceRange();
645   }
646   // Return invalid source range (can be checked by client).
647   else {
648     return SourceRange{};
649   }
650 }
651 
652 //===----------------------------------------------------------------------===//
653 // MemRegionManager methods.
654 //===----------------------------------------------------------------------===//
655 
656 template <typename REG>
657 const REG *MemRegionManager::LazyAllocate(REG*& region) {
658   if (!region) {
659     region = A.Allocate<REG>();
660     new (region) REG(this);
661   }
662 
663   return region;
664 }
665 
666 template <typename REG, typename ARG>
667 const REG *MemRegionManager::LazyAllocate(REG*& region, ARG a) {
668   if (!region) {
669     region = A.Allocate<REG>();
670     new (region) REG(this, a);
671   }
672 
673   return region;
674 }
675 
676 const StackLocalsSpaceRegion*
677 MemRegionManager::getStackLocalsRegion(const StackFrameContext *STC) {
678   assert(STC);
679   StackLocalsSpaceRegion *&R = StackLocalsSpaceRegions[STC];
680 
681   if (R)
682     return R;
683 
684   R = A.Allocate<StackLocalsSpaceRegion>();
685   new (R) StackLocalsSpaceRegion(this, STC);
686   return R;
687 }
688 
689 const StackArgumentsSpaceRegion *
690 MemRegionManager::getStackArgumentsRegion(const StackFrameContext *STC) {
691   assert(STC);
692   StackArgumentsSpaceRegion *&R = StackArgumentsSpaceRegions[STC];
693 
694   if (R)
695     return R;
696 
697   R = A.Allocate<StackArgumentsSpaceRegion>();
698   new (R) StackArgumentsSpaceRegion(this, STC);
699   return R;
700 }
701 
702 const GlobalsSpaceRegion
703 *MemRegionManager::getGlobalsRegion(MemRegion::Kind K,
704                                     const CodeTextRegion *CR) {
705   if (!CR) {
706     if (K == MemRegion::GlobalSystemSpaceRegionKind)
707       return LazyAllocate(SystemGlobals);
708     if (K == MemRegion::GlobalImmutableSpaceRegionKind)
709       return LazyAllocate(ImmutableGlobals);
710     assert(K == MemRegion::GlobalInternalSpaceRegionKind);
711     return LazyAllocate(InternalGlobals);
712   }
713 
714   assert(K == MemRegion::StaticGlobalSpaceRegionKind);
715   StaticGlobalSpaceRegion *&R = StaticsGlobalSpaceRegions[CR];
716   if (R)
717     return R;
718 
719   R = A.Allocate<StaticGlobalSpaceRegion>();
720   new (R) StaticGlobalSpaceRegion(this, CR);
721   return R;
722 }
723 
724 const HeapSpaceRegion *MemRegionManager::getHeapRegion() {
725   return LazyAllocate(heap);
726 }
727 
728 const UnknownSpaceRegion *MemRegionManager::getUnknownRegion() {
729   return LazyAllocate(unknown);
730 }
731 
732 const CodeSpaceRegion *MemRegionManager::getCodeRegion() {
733   return LazyAllocate(code);
734 }
735 
736 //===----------------------------------------------------------------------===//
737 // Constructing regions.
738 //===----------------------------------------------------------------------===//
739 const StringRegion* MemRegionManager::getStringRegion(const StringLiteral* Str){
740   return getSubRegion<StringRegion>(
741       Str, cast<GlobalInternalSpaceRegion>(getGlobalsRegion()));
742 }
743 
744 const ObjCStringRegion *
745 MemRegionManager::getObjCStringRegion(const ObjCStringLiteral* Str){
746   return getSubRegion<ObjCStringRegion>(
747       Str, cast<GlobalInternalSpaceRegion>(getGlobalsRegion()));
748 }
749 
750 /// Look through a chain of LocationContexts to either find the
751 /// StackFrameContext that matches a DeclContext, or find a VarRegion
752 /// for a variable captured by a block.
753 static llvm::PointerUnion<const StackFrameContext *, const VarRegion *>
754 getStackOrCaptureRegionForDeclContext(const LocationContext *LC,
755                                       const DeclContext *DC,
756                                       const VarDecl *VD) {
757   while (LC) {
758     if (const StackFrameContext *SFC = dyn_cast<StackFrameContext>(LC)) {
759       if (cast<DeclContext>(SFC->getDecl()) == DC)
760         return SFC;
761     }
762     if (const BlockInvocationContext *BC =
763         dyn_cast<BlockInvocationContext>(LC)) {
764       const BlockDataRegion *BR =
765         static_cast<const BlockDataRegion*>(BC->getContextData());
766       // FIXME: This can be made more efficient.
767       for (BlockDataRegion::referenced_vars_iterator
768            I = BR->referenced_vars_begin(),
769            E = BR->referenced_vars_end(); I != E; ++I) {
770         if (const VarRegion *VR = dyn_cast<VarRegion>(I.getOriginalRegion()))
771           if (VR->getDecl() == VD)
772             return cast<VarRegion>(I.getCapturedRegion());
773       }
774     }
775 
776     LC = LC->getParent();
777   }
778   return (const StackFrameContext *)nullptr;
779 }
780 
781 const VarRegion* MemRegionManager::getVarRegion(const VarDecl *D,
782                                                 const LocationContext *LC) {
783   const MemRegion *sReg = nullptr;
784 
785   if (D->hasGlobalStorage() && !D->isStaticLocal()) {
786 
787     // First handle the globals defined in system headers.
788     if (C.getSourceManager().isInSystemHeader(D->getLocation())) {
789       // Whitelist the system globals which often DO GET modified, assume the
790       // rest are immutable.
791       if (D->getName().find("errno") != StringRef::npos)
792         sReg = getGlobalsRegion(MemRegion::GlobalSystemSpaceRegionKind);
793       else
794         sReg = getGlobalsRegion(MemRegion::GlobalImmutableSpaceRegionKind);
795 
796     // Treat other globals as GlobalInternal unless they are constants.
797     } else {
798       QualType GQT = D->getType();
799       const Type *GT = GQT.getTypePtrOrNull();
800       // TODO: We could walk the complex types here and see if everything is
801       // constified.
802       if (GT && GQT.isConstQualified() && GT->isArithmeticType())
803         sReg = getGlobalsRegion(MemRegion::GlobalImmutableSpaceRegionKind);
804       else
805         sReg = getGlobalsRegion();
806     }
807 
808   // Finally handle static locals.
809   } else {
810     // FIXME: Once we implement scope handling, we will need to properly lookup
811     // 'D' to the proper LocationContext.
812     const DeclContext *DC = D->getDeclContext();
813     llvm::PointerUnion<const StackFrameContext *, const VarRegion *> V =
814       getStackOrCaptureRegionForDeclContext(LC, DC, D);
815 
816     if (V.is<const VarRegion*>())
817       return V.get<const VarRegion*>();
818 
819     const StackFrameContext *STC = V.get<const StackFrameContext*>();
820 
821     if (!STC) {
822       // FIXME: Assign a more sensible memory space to static locals
823       // we see from within blocks that we analyze as top-level declarations.
824       sReg = getUnknownRegion();
825     } else {
826       if (D->hasLocalStorage()) {
827         sReg = isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)
828                ? static_cast<const MemRegion*>(getStackArgumentsRegion(STC))
829                : static_cast<const MemRegion*>(getStackLocalsRegion(STC));
830       }
831       else {
832         assert(D->isStaticLocal());
833         const Decl *STCD = STC->getDecl();
834         if (isa<FunctionDecl>(STCD) || isa<ObjCMethodDecl>(STCD))
835           sReg = getGlobalsRegion(MemRegion::StaticGlobalSpaceRegionKind,
836                                   getFunctionCodeRegion(cast<NamedDecl>(STCD)));
837         else if (const BlockDecl *BD = dyn_cast<BlockDecl>(STCD)) {
838           // FIXME: The fallback type here is totally bogus -- though it should
839           // never be queried, it will prevent uniquing with the real
840           // BlockCodeRegion. Ideally we'd fix the AST so that we always had a
841           // signature.
842           QualType T;
843           if (const TypeSourceInfo *TSI = BD->getSignatureAsWritten())
844             T = TSI->getType();
845           if (T.isNull())
846             T = getContext().VoidTy;
847           if (!T->getAs<FunctionType>())
848             T = getContext().getFunctionNoProtoType(T);
849           T = getContext().getBlockPointerType(T);
850 
851           const BlockCodeRegion *BTR =
852             getBlockCodeRegion(BD, C.getCanonicalType(T),
853                                STC->getAnalysisDeclContext());
854           sReg = getGlobalsRegion(MemRegion::StaticGlobalSpaceRegionKind,
855                                   BTR);
856         }
857         else {
858           sReg = getGlobalsRegion();
859         }
860       }
861     }
862   }
863 
864   return getSubRegion<VarRegion>(D, sReg);
865 }
866 
867 const VarRegion *MemRegionManager::getVarRegion(const VarDecl *D,
868                                                 const MemRegion *superR) {
869   return getSubRegion<VarRegion>(D, superR);
870 }
871 
872 const BlockDataRegion *
873 MemRegionManager::getBlockDataRegion(const BlockCodeRegion *BC,
874                                      const LocationContext *LC,
875                                      unsigned blockCount) {
876   const MemSpaceRegion *sReg = nullptr;
877   const BlockDecl *BD = BC->getDecl();
878   if (!BD->hasCaptures()) {
879     // This handles 'static' blocks.
880     sReg = getGlobalsRegion(MemRegion::GlobalImmutableSpaceRegionKind);
881   }
882   else {
883     if (LC) {
884       // FIXME: Once we implement scope handling, we want the parent region
885       // to be the scope.
886       const StackFrameContext *STC = LC->getCurrentStackFrame();
887       assert(STC);
888       sReg = getStackLocalsRegion(STC);
889     }
890     else {
891       // We allow 'LC' to be NULL for cases where want BlockDataRegions
892       // without context-sensitivity.
893       sReg = getUnknownRegion();
894     }
895   }
896 
897   return getSubRegion<BlockDataRegion>(BC, LC, blockCount, sReg);
898 }
899 
900 const CXXTempObjectRegion *
901 MemRegionManager::getCXXStaticTempObjectRegion(const Expr *Ex) {
902   return getSubRegion<CXXTempObjectRegion>(
903       Ex, getGlobalsRegion(MemRegion::GlobalInternalSpaceRegionKind, nullptr));
904 }
905 
906 const CompoundLiteralRegion*
907 MemRegionManager::getCompoundLiteralRegion(const CompoundLiteralExpr *CL,
908                                            const LocationContext *LC) {
909   const MemSpaceRegion *sReg = nullptr;
910 
911   if (CL->isFileScope())
912     sReg = getGlobalsRegion();
913   else {
914     const StackFrameContext *STC = LC->getCurrentStackFrame();
915     assert(STC);
916     sReg = getStackLocalsRegion(STC);
917   }
918 
919   return getSubRegion<CompoundLiteralRegion>(CL, sReg);
920 }
921 
922 const ElementRegion*
923 MemRegionManager::getElementRegion(QualType elementType, NonLoc Idx,
924                                    const SubRegion* superRegion,
925                                    ASTContext &Ctx){
926   QualType T = Ctx.getCanonicalType(elementType).getUnqualifiedType();
927 
928   llvm::FoldingSetNodeID ID;
929   ElementRegion::ProfileRegion(ID, T, Idx, superRegion);
930 
931   void *InsertPos;
932   MemRegion* data = Regions.FindNodeOrInsertPos(ID, InsertPos);
933   ElementRegion* R = cast_or_null<ElementRegion>(data);
934 
935   if (!R) {
936     R = A.Allocate<ElementRegion>();
937     new (R) ElementRegion(T, Idx, superRegion);
938     Regions.InsertNode(R, InsertPos);
939   }
940 
941   return R;
942 }
943 
944 const FunctionCodeRegion *
945 MemRegionManager::getFunctionCodeRegion(const NamedDecl *FD) {
946   return getSubRegion<FunctionCodeRegion>(FD, getCodeRegion());
947 }
948 
949 const BlockCodeRegion *
950 MemRegionManager::getBlockCodeRegion(const BlockDecl *BD, CanQualType locTy,
951                                      AnalysisDeclContext *AC) {
952   return getSubRegion<BlockCodeRegion>(BD, locTy, AC, getCodeRegion());
953 }
954 
955 
956 /// getSymbolicRegion - Retrieve or create a "symbolic" memory region.
957 const SymbolicRegion *MemRegionManager::getSymbolicRegion(SymbolRef sym) {
958   return getSubRegion<SymbolicRegion>(sym, getUnknownRegion());
959 }
960 
961 const SymbolicRegion *MemRegionManager::getSymbolicHeapRegion(SymbolRef Sym) {
962   return getSubRegion<SymbolicRegion>(Sym, getHeapRegion());
963 }
964 
965 const FieldRegion*
966 MemRegionManager::getFieldRegion(const FieldDecl *d,
967                                  const SubRegion* superRegion){
968   return getSubRegion<FieldRegion>(d, superRegion);
969 }
970 
971 const ObjCIvarRegion*
972 MemRegionManager::getObjCIvarRegion(const ObjCIvarDecl *d,
973                                     const SubRegion* superRegion) {
974   return getSubRegion<ObjCIvarRegion>(d, superRegion);
975 }
976 
977 const CXXTempObjectRegion*
978 MemRegionManager::getCXXTempObjectRegion(Expr const *E,
979                                          LocationContext const *LC) {
980   const StackFrameContext *SFC = LC->getCurrentStackFrame();
981   assert(SFC);
982   return getSubRegion<CXXTempObjectRegion>(E, getStackLocalsRegion(SFC));
983 }
984 
985 /// Checks whether \p BaseClass is a valid virtual or direct non-virtual base
986 /// class of the type of \p Super.
987 static bool isValidBaseClass(const CXXRecordDecl *BaseClass,
988                              const TypedValueRegion *Super,
989                              bool IsVirtual) {
990   BaseClass = BaseClass->getCanonicalDecl();
991 
992   const CXXRecordDecl *Class = Super->getValueType()->getAsCXXRecordDecl();
993   if (!Class)
994     return true;
995 
996   if (IsVirtual)
997     return Class->isVirtuallyDerivedFrom(BaseClass);
998 
999   for (const auto &I : Class->bases()) {
1000     if (I.getType()->getAsCXXRecordDecl()->getCanonicalDecl() == BaseClass)
1001       return true;
1002   }
1003 
1004   return false;
1005 }
1006 
1007 const CXXBaseObjectRegion *
1008 MemRegionManager::getCXXBaseObjectRegion(const CXXRecordDecl *RD,
1009                                          const SubRegion *Super,
1010                                          bool IsVirtual) {
1011   if (isa<TypedValueRegion>(Super)) {
1012     assert(isValidBaseClass(RD, dyn_cast<TypedValueRegion>(Super), IsVirtual));
1013     (void)&isValidBaseClass;
1014 
1015     if (IsVirtual) {
1016       // Virtual base regions should not be layered, since the layout rules
1017       // are different.
1018       while (const CXXBaseObjectRegion *Base =
1019                dyn_cast<CXXBaseObjectRegion>(Super)) {
1020         Super = cast<SubRegion>(Base->getSuperRegion());
1021       }
1022       assert(Super && !isa<MemSpaceRegion>(Super));
1023     }
1024   }
1025 
1026   return getSubRegion<CXXBaseObjectRegion>(RD, IsVirtual, Super);
1027 }
1028 
1029 const CXXThisRegion*
1030 MemRegionManager::getCXXThisRegion(QualType thisPointerTy,
1031                                    const LocationContext *LC) {
1032   const PointerType *PT = thisPointerTy->getAs<PointerType>();
1033   assert(PT);
1034   // Inside the body of the operator() of a lambda a this expr might refer to an
1035   // object in one of the parent location contexts.
1036   const auto *D = dyn_cast<CXXMethodDecl>(LC->getDecl());
1037   // FIXME: when operator() of lambda is analyzed as a top level function and
1038   // 'this' refers to a this to the enclosing scope, there is no right region to
1039   // return.
1040   while (!LC->inTopFrame() &&
1041          (!D || D->isStatic() ||
1042           PT != D->getThisType(getContext())->getAs<PointerType>())) {
1043     LC = LC->getParent();
1044     D = dyn_cast<CXXMethodDecl>(LC->getDecl());
1045   }
1046   const StackFrameContext *STC = LC->getCurrentStackFrame();
1047   assert(STC);
1048   return getSubRegion<CXXThisRegion>(PT, getStackArgumentsRegion(STC));
1049 }
1050 
1051 const AllocaRegion*
1052 MemRegionManager::getAllocaRegion(const Expr *E, unsigned cnt,
1053                                   const LocationContext *LC) {
1054   const StackFrameContext *STC = LC->getCurrentStackFrame();
1055   assert(STC);
1056   return getSubRegion<AllocaRegion>(E, cnt, getStackLocalsRegion(STC));
1057 }
1058 
1059 const MemSpaceRegion *MemRegion::getMemorySpace() const {
1060   const MemRegion *R = this;
1061   const SubRegion* SR = dyn_cast<SubRegion>(this);
1062 
1063   while (SR) {
1064     R = SR->getSuperRegion();
1065     SR = dyn_cast<SubRegion>(R);
1066   }
1067 
1068   return dyn_cast<MemSpaceRegion>(R);
1069 }
1070 
1071 bool MemRegion::hasStackStorage() const {
1072   return isa<StackSpaceRegion>(getMemorySpace());
1073 }
1074 
1075 bool MemRegion::hasStackNonParametersStorage() const {
1076   return isa<StackLocalsSpaceRegion>(getMemorySpace());
1077 }
1078 
1079 bool MemRegion::hasStackParametersStorage() const {
1080   return isa<StackArgumentsSpaceRegion>(getMemorySpace());
1081 }
1082 
1083 bool MemRegion::hasGlobalsOrParametersStorage() const {
1084   const MemSpaceRegion *MS = getMemorySpace();
1085   return isa<StackArgumentsSpaceRegion>(MS) ||
1086          isa<GlobalsSpaceRegion>(MS);
1087 }
1088 
1089 // getBaseRegion strips away all elements and fields, and get the base region
1090 // of them.
1091 const MemRegion *MemRegion::getBaseRegion() const {
1092   const MemRegion *R = this;
1093   while (true) {
1094     switch (R->getKind()) {
1095       case MemRegion::ElementRegionKind:
1096       case MemRegion::FieldRegionKind:
1097       case MemRegion::ObjCIvarRegionKind:
1098       case MemRegion::CXXBaseObjectRegionKind:
1099         R = cast<SubRegion>(R)->getSuperRegion();
1100         continue;
1101       default:
1102         break;
1103     }
1104     break;
1105   }
1106   return R;
1107 }
1108 
1109 bool MemRegion::isSubRegionOf(const MemRegion *R) const {
1110   return false;
1111 }
1112 
1113 //===----------------------------------------------------------------------===//
1114 // View handling.
1115 //===----------------------------------------------------------------------===//
1116 
1117 const MemRegion *MemRegion::StripCasts(bool StripBaseCasts) const {
1118   const MemRegion *R = this;
1119   while (true) {
1120     switch (R->getKind()) {
1121     case ElementRegionKind: {
1122       const ElementRegion *ER = cast<ElementRegion>(R);
1123       if (!ER->getIndex().isZeroConstant())
1124         return R;
1125       R = ER->getSuperRegion();
1126       break;
1127     }
1128     case CXXBaseObjectRegionKind:
1129       if (!StripBaseCasts)
1130         return R;
1131       R = cast<CXXBaseObjectRegion>(R)->getSuperRegion();
1132       break;
1133     default:
1134       return R;
1135     }
1136   }
1137 }
1138 
1139 const SymbolicRegion *MemRegion::getSymbolicBase() const {
1140   const SubRegion *SubR = dyn_cast<SubRegion>(this);
1141 
1142   while (SubR) {
1143     if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(SubR))
1144       return SymR;
1145     SubR = dyn_cast<SubRegion>(SubR->getSuperRegion());
1146   }
1147   return nullptr;
1148 }
1149 
1150 RegionRawOffset ElementRegion::getAsArrayOffset() const {
1151   CharUnits offset = CharUnits::Zero();
1152   const ElementRegion *ER = this;
1153   const MemRegion *superR = nullptr;
1154   ASTContext &C = getContext();
1155 
1156   // FIXME: Handle multi-dimensional arrays.
1157 
1158   while (ER) {
1159     superR = ER->getSuperRegion();
1160 
1161     // FIXME: generalize to symbolic offsets.
1162     SVal index = ER->getIndex();
1163     if (Optional<nonloc::ConcreteInt> CI = index.getAs<nonloc::ConcreteInt>()) {
1164       // Update the offset.
1165       int64_t i = CI->getValue().getSExtValue();
1166 
1167       if (i != 0) {
1168         QualType elemType = ER->getElementType();
1169 
1170         // If we are pointing to an incomplete type, go no further.
1171         if (elemType->isIncompleteType()) {
1172           superR = ER;
1173           break;
1174         }
1175 
1176         CharUnits size = C.getTypeSizeInChars(elemType);
1177         offset += (i * size);
1178       }
1179 
1180       // Go to the next ElementRegion (if any).
1181       ER = dyn_cast<ElementRegion>(superR);
1182       continue;
1183     }
1184 
1185     return nullptr;
1186   }
1187 
1188   assert(superR && "super region cannot be NULL");
1189   return RegionRawOffset(superR, offset);
1190 }
1191 
1192 
1193 /// Returns true if \p Base is an immediate base class of \p Child
1194 static bool isImmediateBase(const CXXRecordDecl *Child,
1195                             const CXXRecordDecl *Base) {
1196   assert(Child && "Child must not be null");
1197   // Note that we do NOT canonicalize the base class here, because
1198   // ASTRecordLayout doesn't either. If that leads us down the wrong path,
1199   // so be it; at least we won't crash.
1200   for (const auto &I : Child->bases()) {
1201     if (I.getType()->getAsCXXRecordDecl() == Base)
1202       return true;
1203   }
1204 
1205   return false;
1206 }
1207 
1208 RegionOffset MemRegion::getAsOffset() const {
1209   const MemRegion *R = this;
1210   const MemRegion *SymbolicOffsetBase = nullptr;
1211   int64_t Offset = 0;
1212 
1213   while (1) {
1214     switch (R->getKind()) {
1215     case CodeSpaceRegionKind:
1216     case StackLocalsSpaceRegionKind:
1217     case StackArgumentsSpaceRegionKind:
1218     case HeapSpaceRegionKind:
1219     case UnknownSpaceRegionKind:
1220     case StaticGlobalSpaceRegionKind:
1221     case GlobalInternalSpaceRegionKind:
1222     case GlobalSystemSpaceRegionKind:
1223     case GlobalImmutableSpaceRegionKind:
1224       // Stores can bind directly to a region space to set a default value.
1225       assert(Offset == 0 && !SymbolicOffsetBase);
1226       goto Finish;
1227 
1228     case FunctionCodeRegionKind:
1229     case BlockCodeRegionKind:
1230     case BlockDataRegionKind:
1231       // These will never have bindings, but may end up having values requested
1232       // if the user does some strange casting.
1233       if (Offset != 0)
1234         SymbolicOffsetBase = R;
1235       goto Finish;
1236 
1237     case SymbolicRegionKind:
1238     case AllocaRegionKind:
1239     case CompoundLiteralRegionKind:
1240     case CXXThisRegionKind:
1241     case StringRegionKind:
1242     case ObjCStringRegionKind:
1243     case VarRegionKind:
1244     case CXXTempObjectRegionKind:
1245       // Usual base regions.
1246       goto Finish;
1247 
1248     case ObjCIvarRegionKind:
1249       // This is a little strange, but it's a compromise between
1250       // ObjCIvarRegions having unknown compile-time offsets (when using the
1251       // non-fragile runtime) and yet still being distinct, non-overlapping
1252       // regions. Thus we treat them as "like" base regions for the purposes
1253       // of computing offsets.
1254       goto Finish;
1255 
1256     case CXXBaseObjectRegionKind: {
1257       const CXXBaseObjectRegion *BOR = cast<CXXBaseObjectRegion>(R);
1258       R = BOR->getSuperRegion();
1259 
1260       QualType Ty;
1261       bool RootIsSymbolic = false;
1262       if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) {
1263         Ty = TVR->getDesugaredValueType(getContext());
1264       } else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
1265         // If our base region is symbolic, we don't know what type it really is.
1266         // Pretend the type of the symbol is the true dynamic type.
1267         // (This will at least be self-consistent for the life of the symbol.)
1268         Ty = SR->getSymbol()->getType()->getPointeeType();
1269         RootIsSymbolic = true;
1270       }
1271 
1272       const CXXRecordDecl *Child = Ty->getAsCXXRecordDecl();
1273       if (!Child) {
1274         // We cannot compute the offset of the base class.
1275         SymbolicOffsetBase = R;
1276       } else {
1277         if (RootIsSymbolic) {
1278           // Base layers on symbolic regions may not be type-correct.
1279           // Double-check the inheritance here, and revert to a symbolic offset
1280           // if it's invalid (e.g. due to a reinterpret_cast).
1281           if (BOR->isVirtual()) {
1282             if (!Child->isVirtuallyDerivedFrom(BOR->getDecl()))
1283               SymbolicOffsetBase = R;
1284           } else {
1285             if (!isImmediateBase(Child, BOR->getDecl()))
1286               SymbolicOffsetBase = R;
1287           }
1288         }
1289       }
1290 
1291       // Don't bother calculating precise offsets if we already have a
1292       // symbolic offset somewhere in the chain.
1293       if (SymbolicOffsetBase)
1294         continue;
1295 
1296       CharUnits BaseOffset;
1297       const ASTRecordLayout &Layout = getContext().getASTRecordLayout(Child);
1298       if (BOR->isVirtual())
1299         BaseOffset = Layout.getVBaseClassOffset(BOR->getDecl());
1300       else
1301         BaseOffset = Layout.getBaseClassOffset(BOR->getDecl());
1302 
1303       // The base offset is in chars, not in bits.
1304       Offset += BaseOffset.getQuantity() * getContext().getCharWidth();
1305       break;
1306     }
1307     case ElementRegionKind: {
1308       const ElementRegion *ER = cast<ElementRegion>(R);
1309       R = ER->getSuperRegion();
1310 
1311       QualType EleTy = ER->getValueType();
1312       if (EleTy->isIncompleteType()) {
1313         // We cannot compute the offset of the base class.
1314         SymbolicOffsetBase = R;
1315         continue;
1316       }
1317 
1318       SVal Index = ER->getIndex();
1319       if (Optional<nonloc::ConcreteInt> CI =
1320               Index.getAs<nonloc::ConcreteInt>()) {
1321         // Don't bother calculating precise offsets if we already have a
1322         // symbolic offset somewhere in the chain.
1323         if (SymbolicOffsetBase)
1324           continue;
1325 
1326         int64_t i = CI->getValue().getSExtValue();
1327         // This type size is in bits.
1328         Offset += i * getContext().getTypeSize(EleTy);
1329       } else {
1330         // We cannot compute offset for non-concrete index.
1331         SymbolicOffsetBase = R;
1332       }
1333       break;
1334     }
1335     case FieldRegionKind: {
1336       const FieldRegion *FR = cast<FieldRegion>(R);
1337       R = FR->getSuperRegion();
1338 
1339       const RecordDecl *RD = FR->getDecl()->getParent();
1340       if (RD->isUnion() || !RD->isCompleteDefinition()) {
1341         // We cannot compute offset for incomplete type.
1342         // For unions, we could treat everything as offset 0, but we'd rather
1343         // treat each field as a symbolic offset so they aren't stored on top
1344         // of each other, since we depend on things in typed regions actually
1345         // matching their types.
1346         SymbolicOffsetBase = R;
1347       }
1348 
1349       // Don't bother calculating precise offsets if we already have a
1350       // symbolic offset somewhere in the chain.
1351       if (SymbolicOffsetBase)
1352         continue;
1353 
1354       // Get the field number.
1355       unsigned idx = 0;
1356       for (RecordDecl::field_iterator FI = RD->field_begin(),
1357              FE = RD->field_end(); FI != FE; ++FI, ++idx) {
1358         if (FR->getDecl() == *FI)
1359           break;
1360       }
1361       const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
1362       // This is offset in bits.
1363       Offset += Layout.getFieldOffset(idx);
1364       break;
1365     }
1366     }
1367   }
1368 
1369  Finish:
1370   if (SymbolicOffsetBase)
1371     return RegionOffset(SymbolicOffsetBase, RegionOffset::Symbolic);
1372   return RegionOffset(R, Offset);
1373 }
1374 
1375 //===----------------------------------------------------------------------===//
1376 // BlockDataRegion
1377 //===----------------------------------------------------------------------===//
1378 
1379 std::pair<const VarRegion *, const VarRegion *>
1380 BlockDataRegion::getCaptureRegions(const VarDecl *VD) {
1381   MemRegionManager &MemMgr = *getMemRegionManager();
1382   const VarRegion *VR = nullptr;
1383   const VarRegion *OriginalVR = nullptr;
1384 
1385   if (!VD->hasAttr<BlocksAttr>() && VD->hasLocalStorage()) {
1386     VR = MemMgr.getVarRegion(VD, this);
1387     OriginalVR = MemMgr.getVarRegion(VD, LC);
1388   }
1389   else {
1390     if (LC) {
1391       VR = MemMgr.getVarRegion(VD, LC);
1392       OriginalVR = VR;
1393     }
1394     else {
1395       VR = MemMgr.getVarRegion(VD, MemMgr.getUnknownRegion());
1396       OriginalVR = MemMgr.getVarRegion(VD, LC);
1397     }
1398   }
1399   return std::make_pair(VR, OriginalVR);
1400 }
1401 
1402 void BlockDataRegion::LazyInitializeReferencedVars() {
1403   if (ReferencedVars)
1404     return;
1405 
1406   AnalysisDeclContext *AC = getCodeRegion()->getAnalysisDeclContext();
1407   const auto &ReferencedBlockVars = AC->getReferencedBlockVars(BC->getDecl());
1408   auto NumBlockVars =
1409       std::distance(ReferencedBlockVars.begin(), ReferencedBlockVars.end());
1410 
1411   if (NumBlockVars == 0) {
1412     ReferencedVars = (void*) 0x1;
1413     return;
1414   }
1415 
1416   MemRegionManager &MemMgr = *getMemRegionManager();
1417   llvm::BumpPtrAllocator &A = MemMgr.getAllocator();
1418   BumpVectorContext BC(A);
1419 
1420   typedef BumpVector<const MemRegion*> VarVec;
1421   VarVec *BV = A.Allocate<VarVec>();
1422   new (BV) VarVec(BC, NumBlockVars);
1423   VarVec *BVOriginal = A.Allocate<VarVec>();
1424   new (BVOriginal) VarVec(BC, NumBlockVars);
1425 
1426   for (const VarDecl *VD : ReferencedBlockVars) {
1427     const VarRegion *VR = nullptr;
1428     const VarRegion *OriginalVR = nullptr;
1429     std::tie(VR, OriginalVR) = getCaptureRegions(VD);
1430     assert(VR);
1431     assert(OriginalVR);
1432     BV->push_back(VR, BC);
1433     BVOriginal->push_back(OriginalVR, BC);
1434   }
1435 
1436   ReferencedVars = BV;
1437   OriginalVars = BVOriginal;
1438 }
1439 
1440 BlockDataRegion::referenced_vars_iterator
1441 BlockDataRegion::referenced_vars_begin() const {
1442   const_cast<BlockDataRegion*>(this)->LazyInitializeReferencedVars();
1443 
1444   BumpVector<const MemRegion*> *Vec =
1445     static_cast<BumpVector<const MemRegion*>*>(ReferencedVars);
1446 
1447   if (Vec == (void*) 0x1)
1448     return BlockDataRegion::referenced_vars_iterator(nullptr, nullptr);
1449 
1450   BumpVector<const MemRegion*> *VecOriginal =
1451     static_cast<BumpVector<const MemRegion*>*>(OriginalVars);
1452 
1453   return BlockDataRegion::referenced_vars_iterator(Vec->begin(),
1454                                                    VecOriginal->begin());
1455 }
1456 
1457 BlockDataRegion::referenced_vars_iterator
1458 BlockDataRegion::referenced_vars_end() const {
1459   const_cast<BlockDataRegion*>(this)->LazyInitializeReferencedVars();
1460 
1461   BumpVector<const MemRegion*> *Vec =
1462     static_cast<BumpVector<const MemRegion*>*>(ReferencedVars);
1463 
1464   if (Vec == (void*) 0x1)
1465     return BlockDataRegion::referenced_vars_iterator(nullptr, nullptr);
1466 
1467   BumpVector<const MemRegion*> *VecOriginal =
1468     static_cast<BumpVector<const MemRegion*>*>(OriginalVars);
1469 
1470   return BlockDataRegion::referenced_vars_iterator(Vec->end(),
1471                                                    VecOriginal->end());
1472 }
1473 
1474 const VarRegion *BlockDataRegion::getOriginalRegion(const VarRegion *R) const {
1475   for (referenced_vars_iterator I = referenced_vars_begin(),
1476                                 E = referenced_vars_end();
1477        I != E; ++I) {
1478     if (I.getCapturedRegion() == R)
1479       return I.getOriginalRegion();
1480   }
1481   return nullptr;
1482 }
1483 
1484 //===----------------------------------------------------------------------===//
1485 // RegionAndSymbolInvalidationTraits
1486 //===----------------------------------------------------------------------===//
1487 
1488 void RegionAndSymbolInvalidationTraits::setTrait(SymbolRef Sym,
1489                                                  InvalidationKinds IK) {
1490   SymTraitsMap[Sym] |= IK;
1491 }
1492 
1493 void RegionAndSymbolInvalidationTraits::setTrait(const MemRegion *MR,
1494                                                  InvalidationKinds IK) {
1495   assert(MR);
1496   if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1497     setTrait(SR->getSymbol(), IK);
1498   else
1499     MRTraitsMap[MR] |= IK;
1500 }
1501 
1502 bool RegionAndSymbolInvalidationTraits::hasTrait(SymbolRef Sym,
1503                                                  InvalidationKinds IK) const {
1504   const_symbol_iterator I = SymTraitsMap.find(Sym);
1505   if (I != SymTraitsMap.end())
1506     return I->second & IK;
1507 
1508   return false;
1509 }
1510 
1511 bool RegionAndSymbolInvalidationTraits::hasTrait(const MemRegion *MR,
1512                                                  InvalidationKinds IK) const {
1513   if (!MR)
1514     return false;
1515 
1516   if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
1517     return hasTrait(SR->getSymbol(), IK);
1518 
1519   const_region_iterator I = MRTraitsMap.find(MR);
1520   if (I != MRTraitsMap.end())
1521     return I->second & IK;
1522 
1523   return false;
1524 }
1525