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