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/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
18 #include "clang/Analysis/AnalysisContext.h"
19 #include "clang/Analysis/Support/BumpVector.h"
20 #include "clang/AST/CharUnits.h"
21 #include "clang/AST/DeclObjC.h"
22 #include "clang/AST/RecordLayout.h"
23 #include "clang/Basic/SourceManager.h"
24 #include "llvm/Support/raw_ostream.h"
25 
26 using namespace clang;
27 using namespace ento;
28 
29 //===----------------------------------------------------------------------===//
30 // MemRegion Construction.
31 //===----------------------------------------------------------------------===//
32 
33 template<typename RegionTy> struct MemRegionManagerTrait;
34 
35 template <typename RegionTy, typename A1>
36 RegionTy* MemRegionManager::getRegion(const A1 a1) {
37 
38   const typename MemRegionManagerTrait<RegionTy>::SuperRegionTy *superRegion =
39   MemRegionManagerTrait<RegionTy>::getSuperRegion(*this, a1);
40 
41   llvm::FoldingSetNodeID ID;
42   RegionTy::ProfileRegion(ID, a1, superRegion);
43   void *InsertPos;
44   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
45                                                                    InsertPos));
46 
47   if (!R) {
48     R = (RegionTy*) A.Allocate<RegionTy>();
49     new (R) RegionTy(a1, superRegion);
50     Regions.InsertNode(R, InsertPos);
51   }
52 
53   return R;
54 }
55 
56 template <typename RegionTy, typename A1>
57 RegionTy* MemRegionManager::getSubRegion(const A1 a1,
58                                          const MemRegion *superRegion) {
59   llvm::FoldingSetNodeID ID;
60   RegionTy::ProfileRegion(ID, a1, superRegion);
61   void *InsertPos;
62   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
63                                                                    InsertPos));
64 
65   if (!R) {
66     R = (RegionTy*) A.Allocate<RegionTy>();
67     new (R) RegionTy(a1, superRegion);
68     Regions.InsertNode(R, InsertPos);
69   }
70 
71   return R;
72 }
73 
74 template <typename RegionTy, typename A1, typename A2>
75 RegionTy* MemRegionManager::getRegion(const A1 a1, const A2 a2) {
76 
77   const typename MemRegionManagerTrait<RegionTy>::SuperRegionTy *superRegion =
78   MemRegionManagerTrait<RegionTy>::getSuperRegion(*this, a1, a2);
79 
80   llvm::FoldingSetNodeID ID;
81   RegionTy::ProfileRegion(ID, a1, a2, superRegion);
82   void *InsertPos;
83   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
84                                                                    InsertPos));
85 
86   if (!R) {
87     R = (RegionTy*) A.Allocate<RegionTy>();
88     new (R) RegionTy(a1, a2, superRegion);
89     Regions.InsertNode(R, InsertPos);
90   }
91 
92   return R;
93 }
94 
95 template <typename RegionTy, typename A1, typename A2>
96 RegionTy* MemRegionManager::getSubRegion(const A1 a1, const A2 a2,
97                                          const MemRegion *superRegion) {
98 
99   llvm::FoldingSetNodeID ID;
100   RegionTy::ProfileRegion(ID, a1, a2, superRegion);
101   void *InsertPos;
102   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
103                                                                    InsertPos));
104 
105   if (!R) {
106     R = (RegionTy*) A.Allocate<RegionTy>();
107     new (R) RegionTy(a1, a2, superRegion);
108     Regions.InsertNode(R, InsertPos);
109   }
110 
111   return R;
112 }
113 
114 template <typename RegionTy, typename A1, typename A2, typename A3>
115 RegionTy* MemRegionManager::getSubRegion(const A1 a1, const A2 a2, const A3 a3,
116                                          const MemRegion *superRegion) {
117 
118   llvm::FoldingSetNodeID ID;
119   RegionTy::ProfileRegion(ID, a1, a2, a3, superRegion);
120   void *InsertPos;
121   RegionTy* R = cast_or_null<RegionTy>(Regions.FindNodeOrInsertPos(ID,
122                                                                    InsertPos));
123 
124   if (!R) {
125     R = (RegionTy*) A.Allocate<RegionTy>();
126     new (R) RegionTy(a1, a2, a3, superRegion);
127     Regions.InsertNode(R, InsertPos);
128   }
129 
130   return R;
131 }
132 
133 //===----------------------------------------------------------------------===//
134 // Object destruction.
135 //===----------------------------------------------------------------------===//
136 
137 MemRegion::~MemRegion() {}
138 
139 MemRegionManager::~MemRegionManager() {
140   // All regions and their data are BumpPtrAllocated.  No need to call
141   // their destructors.
142 }
143 
144 //===----------------------------------------------------------------------===//
145 // Basic methods.
146 //===----------------------------------------------------------------------===//
147 
148 bool SubRegion::isSubRegionOf(const MemRegion* R) const {
149   const MemRegion* r = getSuperRegion();
150   while (r != 0) {
151     if (r == R)
152       return true;
153     if (const SubRegion* sr = dyn_cast<SubRegion>(r))
154       r = sr->getSuperRegion();
155     else
156       break;
157   }
158   return false;
159 }
160 
161 MemRegionManager* SubRegion::getMemRegionManager() const {
162   const SubRegion* r = this;
163   do {
164     const MemRegion *superRegion = r->getSuperRegion();
165     if (const SubRegion *sr = dyn_cast<SubRegion>(superRegion)) {
166       r = sr;
167       continue;
168     }
169     return superRegion->getMemRegionManager();
170   } while (1);
171 }
172 
173 const StackFrameContext *VarRegion::getStackFrame() const {
174   const StackSpaceRegion *SSR = dyn_cast<StackSpaceRegion>(getMemorySpace());
175   return SSR ? SSR->getStackFrame() : NULL;
176 }
177 
178 //===----------------------------------------------------------------------===//
179 // Region extents.
180 //===----------------------------------------------------------------------===//
181 
182 DefinedOrUnknownSVal DeclRegion::getExtent(SValBuilder &svalBuilder) const {
183   ASTContext &Ctx = svalBuilder.getContext();
184   QualType T = getDesugaredValueType(Ctx);
185 
186   if (isa<VariableArrayType>(T))
187     return nonloc::SymbolVal(svalBuilder.getSymbolManager().getExtentSymbol(this));
188   if (isa<IncompleteArrayType>(T))
189     return UnknownVal();
190 
191   CharUnits size = Ctx.getTypeSizeInChars(T);
192   QualType sizeTy = svalBuilder.getArrayIndexType();
193   return svalBuilder.makeIntVal(size.getQuantity(), sizeTy);
194 }
195 
196 DefinedOrUnknownSVal FieldRegion::getExtent(SValBuilder &svalBuilder) const {
197   DefinedOrUnknownSVal Extent = DeclRegion::getExtent(svalBuilder);
198 
199   // A zero-length array at the end of a struct often stands for dynamically-
200   // allocated extra memory.
201   if (Extent.isZeroConstant()) {
202     QualType T = getDesugaredValueType(svalBuilder.getContext());
203 
204     if (isa<ConstantArrayType>(T))
205       return UnknownVal();
206   }
207 
208   return Extent;
209 }
210 
211 DefinedOrUnknownSVal AllocaRegion::getExtent(SValBuilder &svalBuilder) const {
212   return nonloc::SymbolVal(svalBuilder.getSymbolManager().getExtentSymbol(this));
213 }
214 
215 DefinedOrUnknownSVal SymbolicRegion::getExtent(SValBuilder &svalBuilder) const {
216   return nonloc::SymbolVal(svalBuilder.getSymbolManager().getExtentSymbol(this));
217 }
218 
219 DefinedOrUnknownSVal StringRegion::getExtent(SValBuilder &svalBuilder) const {
220   return svalBuilder.makeIntVal(getStringLiteral()->getByteLength()+1,
221                                 svalBuilder.getArrayIndexType());
222 }
223 
224 ObjCIvarRegion::ObjCIvarRegion(const ObjCIvarDecl *ivd, const MemRegion* sReg)
225   : DeclRegion(ivd, sReg, ObjCIvarRegionKind) {}
226 
227 const ObjCIvarDecl *ObjCIvarRegion::getDecl() const {
228   return cast<ObjCIvarDecl>(D);
229 }
230 
231 QualType ObjCIvarRegion::getValueType() const {
232   return getDecl()->getType();
233 }
234 
235 QualType CXXBaseObjectRegion::getValueType() const {
236   return QualType(decl->getTypeForDecl(), 0);
237 }
238 
239 //===----------------------------------------------------------------------===//
240 // FoldingSet profiling.
241 //===----------------------------------------------------------------------===//
242 
243 void MemSpaceRegion::Profile(llvm::FoldingSetNodeID& ID) const {
244   ID.AddInteger((unsigned)getKind());
245 }
246 
247 void StackSpaceRegion::Profile(llvm::FoldingSetNodeID &ID) const {
248   ID.AddInteger((unsigned)getKind());
249   ID.AddPointer(getStackFrame());
250 }
251 
252 void StaticGlobalSpaceRegion::Profile(llvm::FoldingSetNodeID &ID) const {
253   ID.AddInteger((unsigned)getKind());
254   ID.AddPointer(getCodeRegion());
255 }
256 
257 void StringRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
258                                  const StringLiteral* Str,
259                                  const MemRegion* superRegion) {
260   ID.AddInteger((unsigned) StringRegionKind);
261   ID.AddPointer(Str);
262   ID.AddPointer(superRegion);
263 }
264 
265 void AllocaRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
266                                  const Expr *Ex, unsigned cnt,
267                                  const MemRegion *) {
268   ID.AddInteger((unsigned) AllocaRegionKind);
269   ID.AddPointer(Ex);
270   ID.AddInteger(cnt);
271 }
272 
273 void AllocaRegion::Profile(llvm::FoldingSetNodeID& ID) const {
274   ProfileRegion(ID, Ex, Cnt, superRegion);
275 }
276 
277 void CompoundLiteralRegion::Profile(llvm::FoldingSetNodeID& ID) const {
278   CompoundLiteralRegion::ProfileRegion(ID, CL, superRegion);
279 }
280 
281 void CompoundLiteralRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
282                                           const CompoundLiteralExpr *CL,
283                                           const MemRegion* superRegion) {
284   ID.AddInteger((unsigned) CompoundLiteralRegionKind);
285   ID.AddPointer(CL);
286   ID.AddPointer(superRegion);
287 }
288 
289 void CXXThisRegion::ProfileRegion(llvm::FoldingSetNodeID &ID,
290                                   const PointerType *PT,
291                                   const MemRegion *sRegion) {
292   ID.AddInteger((unsigned) CXXThisRegionKind);
293   ID.AddPointer(PT);
294   ID.AddPointer(sRegion);
295 }
296 
297 void CXXThisRegion::Profile(llvm::FoldingSetNodeID &ID) const {
298   CXXThisRegion::ProfileRegion(ID, ThisPointerTy, superRegion);
299 }
300 
301 void ObjCIvarRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
302                                    const ObjCIvarDecl *ivd,
303                                    const MemRegion* superRegion) {
304   DeclRegion::ProfileRegion(ID, ivd, superRegion, ObjCIvarRegionKind);
305 }
306 
307 void DeclRegion::ProfileRegion(llvm::FoldingSetNodeID& ID, const Decl *D,
308                                const MemRegion* superRegion, Kind k) {
309   ID.AddInteger((unsigned) k);
310   ID.AddPointer(D);
311   ID.AddPointer(superRegion);
312 }
313 
314 void DeclRegion::Profile(llvm::FoldingSetNodeID& ID) const {
315   DeclRegion::ProfileRegion(ID, D, superRegion, getKind());
316 }
317 
318 void VarRegion::Profile(llvm::FoldingSetNodeID &ID) const {
319   VarRegion::ProfileRegion(ID, getDecl(), superRegion);
320 }
321 
322 void SymbolicRegion::ProfileRegion(llvm::FoldingSetNodeID& ID, SymbolRef sym,
323                                    const MemRegion *sreg) {
324   ID.AddInteger((unsigned) MemRegion::SymbolicRegionKind);
325   ID.Add(sym);
326   ID.AddPointer(sreg);
327 }
328 
329 void SymbolicRegion::Profile(llvm::FoldingSetNodeID& ID) const {
330   SymbolicRegion::ProfileRegion(ID, sym, getSuperRegion());
331 }
332 
333 void ElementRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
334                                   QualType ElementType, SVal Idx,
335                                   const MemRegion* superRegion) {
336   ID.AddInteger(MemRegion::ElementRegionKind);
337   ID.Add(ElementType);
338   ID.AddPointer(superRegion);
339   Idx.Profile(ID);
340 }
341 
342 void ElementRegion::Profile(llvm::FoldingSetNodeID& ID) const {
343   ElementRegion::ProfileRegion(ID, ElementType, Index, superRegion);
344 }
345 
346 void FunctionTextRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
347                                        const FunctionDecl *FD,
348                                        const MemRegion*) {
349   ID.AddInteger(MemRegion::FunctionTextRegionKind);
350   ID.AddPointer(FD);
351 }
352 
353 void FunctionTextRegion::Profile(llvm::FoldingSetNodeID& ID) const {
354   FunctionTextRegion::ProfileRegion(ID, FD, superRegion);
355 }
356 
357 void BlockTextRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
358                                     const BlockDecl *BD, CanQualType,
359                                     const AnalysisDeclContext *AC,
360                                     const MemRegion*) {
361   ID.AddInteger(MemRegion::BlockTextRegionKind);
362   ID.AddPointer(BD);
363 }
364 
365 void BlockTextRegion::Profile(llvm::FoldingSetNodeID& ID) const {
366   BlockTextRegion::ProfileRegion(ID, BD, locTy, AC, superRegion);
367 }
368 
369 void BlockDataRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
370                                     const BlockTextRegion *BC,
371                                     const LocationContext *LC,
372                                     const MemRegion *sReg) {
373   ID.AddInteger(MemRegion::BlockDataRegionKind);
374   ID.AddPointer(BC);
375   ID.AddPointer(LC);
376   ID.AddPointer(sReg);
377 }
378 
379 void BlockDataRegion::Profile(llvm::FoldingSetNodeID& ID) const {
380   BlockDataRegion::ProfileRegion(ID, BC, LC, getSuperRegion());
381 }
382 
383 void CXXTempObjectRegion::ProfileRegion(llvm::FoldingSetNodeID &ID,
384                                         Expr const *Ex,
385                                         const MemRegion *sReg) {
386   ID.AddPointer(Ex);
387   ID.AddPointer(sReg);
388 }
389 
390 void CXXTempObjectRegion::Profile(llvm::FoldingSetNodeID &ID) const {
391   ProfileRegion(ID, Ex, getSuperRegion());
392 }
393 
394 void CXXBaseObjectRegion::ProfileRegion(llvm::FoldingSetNodeID &ID,
395                                         const CXXRecordDecl *decl,
396                                         const MemRegion *sReg) {
397   ID.AddPointer(decl);
398   ID.AddPointer(sReg);
399 }
400 
401 void CXXBaseObjectRegion::Profile(llvm::FoldingSetNodeID &ID) const {
402   ProfileRegion(ID, decl, superRegion);
403 }
404 
405 //===----------------------------------------------------------------------===//
406 // Region anchors.
407 //===----------------------------------------------------------------------===//
408 
409 void GlobalsSpaceRegion::anchor() { }
410 void HeapSpaceRegion::anchor() { }
411 void UnknownSpaceRegion::anchor() { }
412 void StackLocalsSpaceRegion::anchor() { }
413 void StackArgumentsSpaceRegion::anchor() { }
414 void TypedRegion::anchor() { }
415 void TypedValueRegion::anchor() { }
416 void CodeTextRegion::anchor() { }
417 void SubRegion::anchor() { }
418 
419 //===----------------------------------------------------------------------===//
420 // Region pretty-printing.
421 //===----------------------------------------------------------------------===//
422 
423 void MemRegion::dump() const {
424   dumpToStream(llvm::errs());
425 }
426 
427 std::string MemRegion::getString() const {
428   std::string s;
429   llvm::raw_string_ostream os(s);
430   dumpToStream(os);
431   return os.str();
432 }
433 
434 void MemRegion::dumpToStream(raw_ostream &os) const {
435   os << "<Unknown Region>";
436 }
437 
438 void AllocaRegion::dumpToStream(raw_ostream &os) const {
439   os << "alloca{" << (void*) Ex << ',' << Cnt << '}';
440 }
441 
442 void FunctionTextRegion::dumpToStream(raw_ostream &os) const {
443   os << "code{" << getDecl()->getDeclName().getAsString() << '}';
444 }
445 
446 void BlockTextRegion::dumpToStream(raw_ostream &os) const {
447   os << "block_code{" << (void*) this << '}';
448 }
449 
450 void BlockDataRegion::dumpToStream(raw_ostream &os) const {
451   os << "block_data{" << BC << '}';
452 }
453 
454 void CompoundLiteralRegion::dumpToStream(raw_ostream &os) const {
455   // FIXME: More elaborate pretty-printing.
456   os << "{ " << (void*) CL <<  " }";
457 }
458 
459 void CXXTempObjectRegion::dumpToStream(raw_ostream &os) const {
460   os << "temp_object{" << getValueType().getAsString() << ','
461      << (void*) Ex << '}';
462 }
463 
464 void CXXBaseObjectRegion::dumpToStream(raw_ostream &os) const {
465   os << "base " << decl->getName();
466 }
467 
468 void CXXThisRegion::dumpToStream(raw_ostream &os) const {
469   os << "this";
470 }
471 
472 void ElementRegion::dumpToStream(raw_ostream &os) const {
473   os << "element{" << superRegion << ','
474      << Index << ',' << getElementType().getAsString() << '}';
475 }
476 
477 void FieldRegion::dumpToStream(raw_ostream &os) const {
478   os << superRegion << "->" << *getDecl();
479 }
480 
481 void ObjCIvarRegion::dumpToStream(raw_ostream &os) const {
482   os << "ivar{" << superRegion << ',' << *getDecl() << '}';
483 }
484 
485 void StringRegion::dumpToStream(raw_ostream &os) const {
486   Str->printPretty(os, 0, PrintingPolicy(getContext().getLangOptions()));
487 }
488 
489 void SymbolicRegion::dumpToStream(raw_ostream &os) const {
490   os << "SymRegion{" << sym << '}';
491 }
492 
493 void VarRegion::dumpToStream(raw_ostream &os) const {
494   os << *cast<VarDecl>(D);
495 }
496 
497 void RegionRawOffset::dump() const {
498   dumpToStream(llvm::errs());
499 }
500 
501 void RegionRawOffset::dumpToStream(raw_ostream &os) const {
502   os << "raw_offset{" << getRegion() << ',' << getOffset().getQuantity() << '}';
503 }
504 
505 void StaticGlobalSpaceRegion::dumpToStream(raw_ostream &os) const {
506   os << "StaticGlobalsMemSpace{" << CR << '}';
507 }
508 
509 void NonStaticGlobalSpaceRegion::dumpToStream(raw_ostream &os) const {
510   os << "NonStaticGlobalSpaceRegion";
511 }
512 
513 void GlobalInternalSpaceRegion::dumpToStream(raw_ostream &os) const {
514   os << "GlobalInternalSpaceRegion";
515 }
516 
517 void GlobalSystemSpaceRegion::dumpToStream(raw_ostream &os) const {
518   os << "GlobalSystemSpaceRegion";
519 }
520 
521 void GlobalImmutableSpaceRegion::dumpToStream(raw_ostream &os) const {
522   os << "GlobalImmutableSpaceRegion";
523 }
524 
525 //===----------------------------------------------------------------------===//
526 // MemRegionManager methods.
527 //===----------------------------------------------------------------------===//
528 
529 template <typename REG>
530 const REG *MemRegionManager::LazyAllocate(REG*& region) {
531   if (!region) {
532     region = (REG*) A.Allocate<REG>();
533     new (region) REG(this);
534   }
535 
536   return region;
537 }
538 
539 template <typename REG, typename ARG>
540 const REG *MemRegionManager::LazyAllocate(REG*& region, ARG a) {
541   if (!region) {
542     region = (REG*) A.Allocate<REG>();
543     new (region) REG(this, a);
544   }
545 
546   return region;
547 }
548 
549 const StackLocalsSpaceRegion*
550 MemRegionManager::getStackLocalsRegion(const StackFrameContext *STC) {
551   assert(STC);
552   StackLocalsSpaceRegion *&R = StackLocalsSpaceRegions[STC];
553 
554   if (R)
555     return R;
556 
557   R = A.Allocate<StackLocalsSpaceRegion>();
558   new (R) StackLocalsSpaceRegion(this, STC);
559   return R;
560 }
561 
562 const StackArgumentsSpaceRegion *
563 MemRegionManager::getStackArgumentsRegion(const StackFrameContext *STC) {
564   assert(STC);
565   StackArgumentsSpaceRegion *&R = StackArgumentsSpaceRegions[STC];
566 
567   if (R)
568     return R;
569 
570   R = A.Allocate<StackArgumentsSpaceRegion>();
571   new (R) StackArgumentsSpaceRegion(this, STC);
572   return R;
573 }
574 
575 const GlobalsSpaceRegion
576 *MemRegionManager::getGlobalsRegion(MemRegion::Kind K,
577                                     const CodeTextRegion *CR) {
578   if (!CR) {
579     if (K == MemRegion::GlobalSystemSpaceRegionKind)
580       return LazyAllocate(SystemGlobals);
581     if (K == MemRegion::GlobalImmutableSpaceRegionKind)
582       return LazyAllocate(ImmutableGlobals);
583     assert(K == MemRegion::GlobalInternalSpaceRegionKind);
584     return LazyAllocate(InternalGlobals);
585   }
586 
587   assert(K == MemRegion::StaticGlobalSpaceRegionKind);
588   StaticGlobalSpaceRegion *&R = StaticsGlobalSpaceRegions[CR];
589   if (R)
590     return R;
591 
592   R = A.Allocate<StaticGlobalSpaceRegion>();
593   new (R) StaticGlobalSpaceRegion(this, CR);
594   return R;
595 }
596 
597 const HeapSpaceRegion *MemRegionManager::getHeapRegion() {
598   return LazyAllocate(heap);
599 }
600 
601 const MemSpaceRegion *MemRegionManager::getUnknownRegion() {
602   return LazyAllocate(unknown);
603 }
604 
605 const MemSpaceRegion *MemRegionManager::getCodeRegion() {
606   return LazyAllocate(code);
607 }
608 
609 //===----------------------------------------------------------------------===//
610 // Constructing regions.
611 //===----------------------------------------------------------------------===//
612 const StringRegion* MemRegionManager::getStringRegion(const StringLiteral* Str){
613   return getSubRegion<StringRegion>(Str, getGlobalsRegion());
614 }
615 
616 const VarRegion* MemRegionManager::getVarRegion(const VarDecl *D,
617                                                 const LocationContext *LC) {
618   const MemRegion *sReg = 0;
619 
620   if (D->hasGlobalStorage() && !D->isStaticLocal()) {
621 
622     // First handle the globals defined in system headers.
623     if (C.getSourceManager().isInSystemHeader(D->getLocation())) {
624       // Whitelist the system globals which often DO GET modified, assume the
625       // rest are immutable.
626       if (D->getName().find("errno") != StringRef::npos)
627         sReg = getGlobalsRegion(MemRegion::GlobalSystemSpaceRegionKind);
628       else
629         sReg = getGlobalsRegion(MemRegion::GlobalImmutableSpaceRegionKind);
630 
631     // Treat other globals as GlobalInternal unless they are constants.
632     } else {
633       QualType GQT = D->getType();
634       const Type *GT = GQT.getTypePtrOrNull();
635       // TODO: We could walk the complex types here and see if everything is
636       // constified.
637       if (GT && GQT.isConstQualified() && GT->isArithmeticType())
638         sReg = getGlobalsRegion(MemRegion::GlobalImmutableSpaceRegionKind);
639       else
640         sReg = getGlobalsRegion();
641     }
642 
643   // Finally handle static locals.
644   } else {
645     // FIXME: Once we implement scope handling, we will need to properly lookup
646     // 'D' to the proper LocationContext.
647     const DeclContext *DC = D->getDeclContext();
648     const StackFrameContext *STC = LC->getStackFrameForDeclContext(DC);
649 
650     if (!STC)
651       sReg = getUnknownRegion();
652     else {
653       if (D->hasLocalStorage()) {
654         sReg = isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)
655                ? static_cast<const MemRegion*>(getStackArgumentsRegion(STC))
656                : static_cast<const MemRegion*>(getStackLocalsRegion(STC));
657       }
658       else {
659         assert(D->isStaticLocal());
660         const Decl *D = STC->getDecl();
661         if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
662           sReg = getGlobalsRegion(MemRegion::StaticGlobalSpaceRegionKind,
663                                   getFunctionTextRegion(FD));
664         else if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
665           const BlockTextRegion *BTR =
666             getBlockTextRegion(BD,
667                      C.getCanonicalType(BD->getSignatureAsWritten()->getType()),
668                      STC->getAnalysisDeclContext());
669           sReg = getGlobalsRegion(MemRegion::StaticGlobalSpaceRegionKind,
670                                   BTR);
671         }
672         else {
673           // FIXME: For ObjC-methods, we need a new CodeTextRegion.  For now
674           // just use the main global memspace.
675           sReg = getGlobalsRegion();
676         }
677       }
678     }
679   }
680 
681   return getSubRegion<VarRegion>(D, sReg);
682 }
683 
684 const VarRegion *MemRegionManager::getVarRegion(const VarDecl *D,
685                                                 const MemRegion *superR) {
686   return getSubRegion<VarRegion>(D, superR);
687 }
688 
689 const BlockDataRegion *
690 MemRegionManager::getBlockDataRegion(const BlockTextRegion *BC,
691                                      const LocationContext *LC) {
692   const MemRegion *sReg = 0;
693 
694   if (LC) {
695     // FIXME: Once we implement scope handling, we want the parent region
696     // to be the scope.
697     const StackFrameContext *STC = LC->getCurrentStackFrame();
698     assert(STC);
699     sReg = getStackLocalsRegion(STC);
700   }
701   else {
702     // We allow 'LC' to be NULL for cases where want BlockDataRegions
703     // without context-sensitivity.
704     sReg = getUnknownRegion();
705   }
706 
707   return getSubRegion<BlockDataRegion>(BC, LC, sReg);
708 }
709 
710 const CompoundLiteralRegion*
711 MemRegionManager::getCompoundLiteralRegion(const CompoundLiteralExpr *CL,
712                                            const LocationContext *LC) {
713 
714   const MemRegion *sReg = 0;
715 
716   if (CL->isFileScope())
717     sReg = getGlobalsRegion();
718   else {
719     const StackFrameContext *STC = LC->getCurrentStackFrame();
720     assert(STC);
721     sReg = getStackLocalsRegion(STC);
722   }
723 
724   return getSubRegion<CompoundLiteralRegion>(CL, sReg);
725 }
726 
727 const ElementRegion*
728 MemRegionManager::getElementRegion(QualType elementType, NonLoc Idx,
729                                    const MemRegion* superRegion,
730                                    ASTContext &Ctx){
731 
732   QualType T = Ctx.getCanonicalType(elementType).getUnqualifiedType();
733 
734   llvm::FoldingSetNodeID ID;
735   ElementRegion::ProfileRegion(ID, T, Idx, superRegion);
736 
737   void *InsertPos;
738   MemRegion* data = Regions.FindNodeOrInsertPos(ID, InsertPos);
739   ElementRegion* R = cast_or_null<ElementRegion>(data);
740 
741   if (!R) {
742     R = (ElementRegion*) A.Allocate<ElementRegion>();
743     new (R) ElementRegion(T, Idx, superRegion);
744     Regions.InsertNode(R, InsertPos);
745   }
746 
747   return R;
748 }
749 
750 const FunctionTextRegion *
751 MemRegionManager::getFunctionTextRegion(const FunctionDecl *FD) {
752   return getSubRegion<FunctionTextRegion>(FD, getCodeRegion());
753 }
754 
755 const BlockTextRegion *
756 MemRegionManager::getBlockTextRegion(const BlockDecl *BD, CanQualType locTy,
757                                      AnalysisDeclContext *AC) {
758   return getSubRegion<BlockTextRegion>(BD, locTy, AC, getCodeRegion());
759 }
760 
761 
762 /// getSymbolicRegion - Retrieve or create a "symbolic" memory region.
763 const SymbolicRegion *MemRegionManager::getSymbolicRegion(SymbolRef sym) {
764   return getSubRegion<SymbolicRegion>(sym, getUnknownRegion());
765 }
766 
767 const FieldRegion*
768 MemRegionManager::getFieldRegion(const FieldDecl *d,
769                                  const MemRegion* superRegion){
770   return getSubRegion<FieldRegion>(d, superRegion);
771 }
772 
773 const ObjCIvarRegion*
774 MemRegionManager::getObjCIvarRegion(const ObjCIvarDecl *d,
775                                     const MemRegion* superRegion) {
776   return getSubRegion<ObjCIvarRegion>(d, superRegion);
777 }
778 
779 const CXXTempObjectRegion*
780 MemRegionManager::getCXXTempObjectRegion(Expr const *E,
781                                          LocationContext const *LC) {
782   const StackFrameContext *SFC = LC->getCurrentStackFrame();
783   assert(SFC);
784   return getSubRegion<CXXTempObjectRegion>(E, getStackLocalsRegion(SFC));
785 }
786 
787 const CXXBaseObjectRegion *
788 MemRegionManager::getCXXBaseObjectRegion(const CXXRecordDecl *decl,
789                                          const MemRegion *superRegion) {
790   return getSubRegion<CXXBaseObjectRegion>(decl, superRegion);
791 }
792 
793 const CXXThisRegion*
794 MemRegionManager::getCXXThisRegion(QualType thisPointerTy,
795                                    const LocationContext *LC) {
796   const StackFrameContext *STC = LC->getCurrentStackFrame();
797   assert(STC);
798   const PointerType *PT = thisPointerTy->getAs<PointerType>();
799   assert(PT);
800   return getSubRegion<CXXThisRegion>(PT, getStackArgumentsRegion(STC));
801 }
802 
803 const AllocaRegion*
804 MemRegionManager::getAllocaRegion(const Expr *E, unsigned cnt,
805                                   const LocationContext *LC) {
806   const StackFrameContext *STC = LC->getCurrentStackFrame();
807   assert(STC);
808   return getSubRegion<AllocaRegion>(E, cnt, getStackLocalsRegion(STC));
809 }
810 
811 const MemSpaceRegion *MemRegion::getMemorySpace() const {
812   const MemRegion *R = this;
813   const SubRegion* SR = dyn_cast<SubRegion>(this);
814 
815   while (SR) {
816     R = SR->getSuperRegion();
817     SR = dyn_cast<SubRegion>(R);
818   }
819 
820   return dyn_cast<MemSpaceRegion>(R);
821 }
822 
823 bool MemRegion::hasStackStorage() const {
824   return isa<StackSpaceRegion>(getMemorySpace());
825 }
826 
827 bool MemRegion::hasStackNonParametersStorage() const {
828   return isa<StackLocalsSpaceRegion>(getMemorySpace());
829 }
830 
831 bool MemRegion::hasStackParametersStorage() const {
832   return isa<StackArgumentsSpaceRegion>(getMemorySpace());
833 }
834 
835 bool MemRegion::hasGlobalsOrParametersStorage() const {
836   const MemSpaceRegion *MS = getMemorySpace();
837   return isa<StackArgumentsSpaceRegion>(MS) ||
838          isa<GlobalsSpaceRegion>(MS);
839 }
840 
841 // getBaseRegion strips away all elements and fields, and get the base region
842 // of them.
843 const MemRegion *MemRegion::getBaseRegion() const {
844   const MemRegion *R = this;
845   while (true) {
846     switch (R->getKind()) {
847       case MemRegion::ElementRegionKind:
848       case MemRegion::FieldRegionKind:
849       case MemRegion::ObjCIvarRegionKind:
850       case MemRegion::CXXBaseObjectRegionKind:
851         R = cast<SubRegion>(R)->getSuperRegion();
852         continue;
853       default:
854         break;
855     }
856     break;
857   }
858   return R;
859 }
860 
861 //===----------------------------------------------------------------------===//
862 // View handling.
863 //===----------------------------------------------------------------------===//
864 
865 const MemRegion *MemRegion::StripCasts() const {
866   const MemRegion *R = this;
867   while (true) {
868     if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
869       // FIXME: generalize.  Essentially we want to strip away ElementRegions
870       // that were layered on a symbolic region because of casts.  We only
871       // want to strip away ElementRegions, however, where the index is 0.
872       SVal index = ER->getIndex();
873       if (nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(&index)) {
874         if (CI->getValue().getSExtValue() == 0) {
875           R = ER->getSuperRegion();
876           continue;
877         }
878       }
879     }
880     break;
881   }
882   return R;
883 }
884 
885 // FIXME: Merge with the implementation of the same method in Store.cpp
886 static bool IsCompleteType(ASTContext &Ctx, QualType Ty) {
887   if (const RecordType *RT = Ty->getAs<RecordType>()) {
888     const RecordDecl *D = RT->getDecl();
889     if (!D->getDefinition())
890       return false;
891   }
892 
893   return true;
894 }
895 
896 RegionRawOffset ElementRegion::getAsArrayOffset() const {
897   CharUnits offset = CharUnits::Zero();
898   const ElementRegion *ER = this;
899   const MemRegion *superR = NULL;
900   ASTContext &C = getContext();
901 
902   // FIXME: Handle multi-dimensional arrays.
903 
904   while (ER) {
905     superR = ER->getSuperRegion();
906 
907     // FIXME: generalize to symbolic offsets.
908     SVal index = ER->getIndex();
909     if (nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(&index)) {
910       // Update the offset.
911       int64_t i = CI->getValue().getSExtValue();
912 
913       if (i != 0) {
914         QualType elemType = ER->getElementType();
915 
916         // If we are pointing to an incomplete type, go no further.
917         if (!IsCompleteType(C, elemType)) {
918           superR = ER;
919           break;
920         }
921 
922         CharUnits size = C.getTypeSizeInChars(elemType);
923         offset += (i * size);
924       }
925 
926       // Go to the next ElementRegion (if any).
927       ER = dyn_cast<ElementRegion>(superR);
928       continue;
929     }
930 
931     return NULL;
932   }
933 
934   assert(superR && "super region cannot be NULL");
935   return RegionRawOffset(superR, offset);
936 }
937 
938 RegionOffset MemRegion::getAsOffset() const {
939   const MemRegion *R = this;
940   int64_t Offset = 0;
941 
942   while (1) {
943     switch (R->getKind()) {
944     default:
945       return RegionOffset(0);
946     case SymbolicRegionKind:
947     case AllocaRegionKind:
948     case CompoundLiteralRegionKind:
949     case CXXThisRegionKind:
950     case StringRegionKind:
951     case VarRegionKind:
952     case CXXTempObjectRegionKind:
953       goto Finish;
954     case ElementRegionKind: {
955       const ElementRegion *ER = cast<ElementRegion>(R);
956       QualType EleTy = ER->getValueType();
957 
958       if (!IsCompleteType(getContext(), EleTy))
959         return RegionOffset(0);
960 
961       SVal Index = ER->getIndex();
962       if (const nonloc::ConcreteInt *CI=dyn_cast<nonloc::ConcreteInt>(&Index)) {
963         int64_t i = CI->getValue().getSExtValue();
964         CharUnits Size = getContext().getTypeSizeInChars(EleTy);
965         Offset += i * Size.getQuantity() * 8;
966       } else {
967         // We cannot compute offset for non-concrete index.
968         return RegionOffset(0);
969       }
970       R = ER->getSuperRegion();
971       break;
972     }
973     case FieldRegionKind: {
974       const FieldRegion *FR = cast<FieldRegion>(R);
975       const RecordDecl *RD = FR->getDecl()->getParent();
976       if (!RD->isCompleteDefinition())
977         // We cannot compute offset for incomplete type.
978         return RegionOffset(0);
979       // Get the field number.
980       unsigned idx = 0;
981       for (RecordDecl::field_iterator FI = RD->field_begin(),
982              FE = RD->field_end(); FI != FE; ++FI, ++idx)
983         if (FR->getDecl() == *FI)
984           break;
985 
986       const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD);
987       // This is offset in bits.
988       Offset += Layout.getFieldOffset(idx);
989       R = FR->getSuperRegion();
990       break;
991     }
992     }
993   }
994 
995  Finish:
996   return RegionOffset(R, Offset);
997 }
998 
999 //===----------------------------------------------------------------------===//
1000 // BlockDataRegion
1001 //===----------------------------------------------------------------------===//
1002 
1003 void BlockDataRegion::LazyInitializeReferencedVars() {
1004   if (ReferencedVars)
1005     return;
1006 
1007   AnalysisDeclContext *AC = getCodeRegion()->getAnalysisDeclContext();
1008   AnalysisDeclContext::referenced_decls_iterator I, E;
1009   llvm::tie(I, E) = AC->getReferencedBlockVars(BC->getDecl());
1010 
1011   if (I == E) {
1012     ReferencedVars = (void*) 0x1;
1013     return;
1014   }
1015 
1016   MemRegionManager &MemMgr = *getMemRegionManager();
1017   llvm::BumpPtrAllocator &A = MemMgr.getAllocator();
1018   BumpVectorContext BC(A);
1019 
1020   typedef BumpVector<const MemRegion*> VarVec;
1021   VarVec *BV = (VarVec*) A.Allocate<VarVec>();
1022   new (BV) VarVec(BC, E - I);
1023 
1024   for ( ; I != E; ++I) {
1025     const VarDecl *VD = *I;
1026     const VarRegion *VR = 0;
1027 
1028     if (!VD->getAttr<BlocksAttr>() && VD->hasLocalStorage())
1029       VR = MemMgr.getVarRegion(VD, this);
1030     else {
1031       if (LC)
1032         VR = MemMgr.getVarRegion(VD, LC);
1033       else {
1034         VR = MemMgr.getVarRegion(VD, MemMgr.getUnknownRegion());
1035       }
1036     }
1037 
1038     assert(VR);
1039     BV->push_back(VR, BC);
1040   }
1041 
1042   ReferencedVars = BV;
1043 }
1044 
1045 BlockDataRegion::referenced_vars_iterator
1046 BlockDataRegion::referenced_vars_begin() const {
1047   const_cast<BlockDataRegion*>(this)->LazyInitializeReferencedVars();
1048 
1049   BumpVector<const MemRegion*> *Vec =
1050     static_cast<BumpVector<const MemRegion*>*>(ReferencedVars);
1051 
1052   return BlockDataRegion::referenced_vars_iterator(Vec == (void*) 0x1 ?
1053                                                    NULL : Vec->begin());
1054 }
1055 
1056 BlockDataRegion::referenced_vars_iterator
1057 BlockDataRegion::referenced_vars_end() const {
1058   const_cast<BlockDataRegion*>(this)->LazyInitializeReferencedVars();
1059 
1060   BumpVector<const MemRegion*> *Vec =
1061     static_cast<BumpVector<const MemRegion*>*>(ReferencedVars);
1062 
1063   return BlockDataRegion::referenced_vars_iterator(Vec == (void*) 0x1 ?
1064                                                    NULL : Vec->end());
1065 }
1066