1 //===--- APValue.cpp - Union class for APFloat/APSInt/Complex -------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 //  This file implements the APValue class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/AST/APValue.h"
14 #include "clang/AST/ASTContext.h"
15 #include "clang/AST/CharUnits.h"
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/Expr.h"
18 #include "clang/AST/Type.h"
19 #include "llvm/Support/ErrorHandling.h"
20 #include "llvm/Support/raw_ostream.h"
21 using namespace clang;
22 
23 /// The identity of a type_info object depends on the canonical unqualified
24 /// type only.
25 TypeInfoLValue::TypeInfoLValue(const Type *T)
26     : T(T->getCanonicalTypeUnqualified().getTypePtr()) {}
27 
28 void TypeInfoLValue::print(llvm::raw_ostream &Out,
29                            const PrintingPolicy &Policy) const {
30   Out << "typeid(";
31   QualType(getType(), 0).print(Out, Policy);
32   Out << ")";
33 }
34 
35 static_assert(
36     1 << llvm::PointerLikeTypeTraits<TypeInfoLValue>::NumLowBitsAvailable <=
37         alignof(Type),
38     "Type is insufficiently aligned");
39 
40 APValue::LValueBase::LValueBase(const ValueDecl *P, unsigned I, unsigned V)
41     : Ptr(P ? cast<ValueDecl>(P->getCanonicalDecl()) : nullptr), Local{I, V} {}
42 APValue::LValueBase::LValueBase(const Expr *P, unsigned I, unsigned V)
43     : Ptr(P), Local{I, V} {}
44 
45 APValue::LValueBase APValue::LValueBase::getDynamicAlloc(DynamicAllocLValue LV,
46                                                          QualType Type) {
47   LValueBase Base;
48   Base.Ptr = LV;
49   Base.DynamicAllocType = Type.getAsOpaquePtr();
50   return Base;
51 }
52 
53 APValue::LValueBase APValue::LValueBase::getTypeInfo(TypeInfoLValue LV,
54                                                      QualType TypeInfo) {
55   LValueBase Base;
56   Base.Ptr = LV;
57   Base.TypeInfoType = TypeInfo.getAsOpaquePtr();
58   return Base;
59 }
60 
61 unsigned APValue::LValueBase::getCallIndex() const {
62   return (is<TypeInfoLValue>() || is<DynamicAllocLValue>()) ? 0
63                                                             : Local.CallIndex;
64 }
65 
66 unsigned APValue::LValueBase::getVersion() const {
67   return (is<TypeInfoLValue>() || is<DynamicAllocLValue>()) ? 0 : Local.Version;
68 }
69 
70 QualType APValue::LValueBase::getTypeInfoType() const {
71   assert(is<TypeInfoLValue>() && "not a type_info lvalue");
72   return QualType::getFromOpaquePtr(TypeInfoType);
73 }
74 
75 QualType APValue::LValueBase::getDynamicAllocType() const {
76   assert(is<DynamicAllocLValue>() && "not a dynamic allocation lvalue");
77   return QualType::getFromOpaquePtr(DynamicAllocType);
78 }
79 
80 namespace clang {
81 bool operator==(const APValue::LValueBase &LHS,
82                 const APValue::LValueBase &RHS) {
83   if (LHS.Ptr != RHS.Ptr)
84     return false;
85   if (LHS.is<TypeInfoLValue>() || LHS.is<DynamicAllocLValue>())
86     return true;
87   return LHS.Local.CallIndex == RHS.Local.CallIndex &&
88          LHS.Local.Version == RHS.Local.Version;
89 }
90 }
91 
92 APValue::LValuePathEntry::LValuePathEntry(BaseOrMemberType BaseOrMember) {
93   if (const Decl *D = BaseOrMember.getPointer())
94     BaseOrMember.setPointer(D->getCanonicalDecl());
95   Value = reinterpret_cast<uintptr_t>(BaseOrMember.getOpaqueValue());
96 }
97 
98 namespace {
99   struct LVBase {
100     APValue::LValueBase Base;
101     CharUnits Offset;
102     unsigned PathLength;
103     bool IsNullPtr : 1;
104     bool IsOnePastTheEnd : 1;
105   };
106 }
107 
108 void *APValue::LValueBase::getOpaqueValue() const {
109   return Ptr.getOpaqueValue();
110 }
111 
112 bool APValue::LValueBase::isNull() const {
113   return Ptr.isNull();
114 }
115 
116 APValue::LValueBase::operator bool () const {
117   return static_cast<bool>(Ptr);
118 }
119 
120 clang::APValue::LValueBase
121 llvm::DenseMapInfo<clang::APValue::LValueBase>::getEmptyKey() {
122   clang::APValue::LValueBase B;
123   B.Ptr = DenseMapInfo<const ValueDecl*>::getEmptyKey();
124   return B;
125 }
126 
127 clang::APValue::LValueBase
128 llvm::DenseMapInfo<clang::APValue::LValueBase>::getTombstoneKey() {
129   clang::APValue::LValueBase B;
130   B.Ptr = DenseMapInfo<const ValueDecl*>::getTombstoneKey();
131   return B;
132 }
133 
134 namespace clang {
135 llvm::hash_code hash_value(const APValue::LValueBase &Base) {
136   if (Base.is<TypeInfoLValue>() || Base.is<DynamicAllocLValue>())
137     return llvm::hash_value(Base.getOpaqueValue());
138   return llvm::hash_combine(Base.getOpaqueValue(), Base.getCallIndex(),
139                             Base.getVersion());
140 }
141 }
142 
143 unsigned llvm::DenseMapInfo<clang::APValue::LValueBase>::getHashValue(
144     const clang::APValue::LValueBase &Base) {
145   return hash_value(Base);
146 }
147 
148 bool llvm::DenseMapInfo<clang::APValue::LValueBase>::isEqual(
149     const clang::APValue::LValueBase &LHS,
150     const clang::APValue::LValueBase &RHS) {
151   return LHS == RHS;
152 }
153 
154 struct APValue::LV : LVBase {
155   static const unsigned InlinePathSpace =
156       (DataSize - sizeof(LVBase)) / sizeof(LValuePathEntry);
157 
158   /// Path - The sequence of base classes, fields and array indices to follow to
159   /// walk from Base to the subobject. When performing GCC-style folding, there
160   /// may not be such a path.
161   union {
162     LValuePathEntry Path[InlinePathSpace];
163     LValuePathEntry *PathPtr;
164   };
165 
166   LV() { PathLength = (unsigned)-1; }
167   ~LV() { resizePath(0); }
168 
169   void resizePath(unsigned Length) {
170     if (Length == PathLength)
171       return;
172     if (hasPathPtr())
173       delete [] PathPtr;
174     PathLength = Length;
175     if (hasPathPtr())
176       PathPtr = new LValuePathEntry[Length];
177   }
178 
179   bool hasPath() const { return PathLength != (unsigned)-1; }
180   bool hasPathPtr() const { return hasPath() && PathLength > InlinePathSpace; }
181 
182   LValuePathEntry *getPath() { return hasPathPtr() ? PathPtr : Path; }
183   const LValuePathEntry *getPath() const {
184     return hasPathPtr() ? PathPtr : Path;
185   }
186 };
187 
188 namespace {
189   struct MemberPointerBase {
190     llvm::PointerIntPair<const ValueDecl*, 1, bool> MemberAndIsDerivedMember;
191     unsigned PathLength;
192   };
193 }
194 
195 struct APValue::MemberPointerData : MemberPointerBase {
196   static const unsigned InlinePathSpace =
197       (DataSize - sizeof(MemberPointerBase)) / sizeof(const CXXRecordDecl*);
198   typedef const CXXRecordDecl *PathElem;
199   union {
200     PathElem Path[InlinePathSpace];
201     PathElem *PathPtr;
202   };
203 
204   MemberPointerData() { PathLength = 0; }
205   ~MemberPointerData() { resizePath(0); }
206 
207   void resizePath(unsigned Length) {
208     if (Length == PathLength)
209       return;
210     if (hasPathPtr())
211       delete [] PathPtr;
212     PathLength = Length;
213     if (hasPathPtr())
214       PathPtr = new PathElem[Length];
215   }
216 
217   bool hasPathPtr() const { return PathLength > InlinePathSpace; }
218 
219   PathElem *getPath() { return hasPathPtr() ? PathPtr : Path; }
220   const PathElem *getPath() const {
221     return hasPathPtr() ? PathPtr : Path;
222   }
223 };
224 
225 // FIXME: Reduce the malloc traffic here.
226 
227 APValue::Arr::Arr(unsigned NumElts, unsigned Size) :
228   Elts(new APValue[NumElts + (NumElts != Size ? 1 : 0)]),
229   NumElts(NumElts), ArrSize(Size) {}
230 APValue::Arr::~Arr() { delete [] Elts; }
231 
232 APValue::StructData::StructData(unsigned NumBases, unsigned NumFields) :
233   Elts(new APValue[NumBases+NumFields]),
234   NumBases(NumBases), NumFields(NumFields) {}
235 APValue::StructData::~StructData() {
236   delete [] Elts;
237 }
238 
239 APValue::UnionData::UnionData() : Field(nullptr), Value(new APValue) {}
240 APValue::UnionData::~UnionData () {
241   delete Value;
242 }
243 
244 APValue::APValue(const APValue &RHS) : Kind(None) {
245   switch (RHS.getKind()) {
246   case None:
247   case Indeterminate:
248     Kind = RHS.getKind();
249     break;
250   case Int:
251     MakeInt();
252     setInt(RHS.getInt());
253     break;
254   case Float:
255     MakeFloat();
256     setFloat(RHS.getFloat());
257     break;
258   case FixedPoint: {
259     APFixedPoint FXCopy = RHS.getFixedPoint();
260     MakeFixedPoint(std::move(FXCopy));
261     break;
262   }
263   case Vector:
264     MakeVector();
265     setVector(((const Vec *)(const char *)RHS.Data.buffer)->Elts,
266               RHS.getVectorLength());
267     break;
268   case ComplexInt:
269     MakeComplexInt();
270     setComplexInt(RHS.getComplexIntReal(), RHS.getComplexIntImag());
271     break;
272   case ComplexFloat:
273     MakeComplexFloat();
274     setComplexFloat(RHS.getComplexFloatReal(), RHS.getComplexFloatImag());
275     break;
276   case LValue:
277     MakeLValue();
278     if (RHS.hasLValuePath())
279       setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), RHS.getLValuePath(),
280                 RHS.isLValueOnePastTheEnd(), RHS.isNullPointer());
281     else
282       setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), NoLValuePath(),
283                 RHS.isNullPointer());
284     break;
285   case Array:
286     MakeArray(RHS.getArrayInitializedElts(), RHS.getArraySize());
287     for (unsigned I = 0, N = RHS.getArrayInitializedElts(); I != N; ++I)
288       getArrayInitializedElt(I) = RHS.getArrayInitializedElt(I);
289     if (RHS.hasArrayFiller())
290       getArrayFiller() = RHS.getArrayFiller();
291     break;
292   case Struct:
293     MakeStruct(RHS.getStructNumBases(), RHS.getStructNumFields());
294     for (unsigned I = 0, N = RHS.getStructNumBases(); I != N; ++I)
295       getStructBase(I) = RHS.getStructBase(I);
296     for (unsigned I = 0, N = RHS.getStructNumFields(); I != N; ++I)
297       getStructField(I) = RHS.getStructField(I);
298     break;
299   case Union:
300     MakeUnion();
301     setUnion(RHS.getUnionField(), RHS.getUnionValue());
302     break;
303   case MemberPointer:
304     MakeMemberPointer(RHS.getMemberPointerDecl(),
305                       RHS.isMemberPointerToDerivedMember(),
306                       RHS.getMemberPointerPath());
307     break;
308   case AddrLabelDiff:
309     MakeAddrLabelDiff();
310     setAddrLabelDiff(RHS.getAddrLabelDiffLHS(), RHS.getAddrLabelDiffRHS());
311     break;
312   }
313 }
314 
315 APValue::APValue(APValue &&RHS) : Kind(RHS.Kind), Data(RHS.Data) {
316   RHS.Kind = None;
317 }
318 
319 APValue &APValue::operator=(const APValue &RHS) {
320   if (this != &RHS)
321     *this = APValue(RHS);
322   return *this;
323 }
324 
325 APValue &APValue::operator=(APValue &&RHS) {
326   if (Kind != None && Kind != Indeterminate)
327     DestroyDataAndMakeUninit();
328   Kind = RHS.Kind;
329   Data = RHS.Data;
330   RHS.Kind = None;
331   return *this;
332 }
333 
334 void APValue::DestroyDataAndMakeUninit() {
335   if (Kind == Int)
336     ((APSInt*)(char*)Data.buffer)->~APSInt();
337   else if (Kind == Float)
338     ((APFloat*)(char*)Data.buffer)->~APFloat();
339   else if (Kind == FixedPoint)
340     ((APFixedPoint *)(char *)Data.buffer)->~APFixedPoint();
341   else if (Kind == Vector)
342     ((Vec*)(char*)Data.buffer)->~Vec();
343   else if (Kind == ComplexInt)
344     ((ComplexAPSInt*)(char*)Data.buffer)->~ComplexAPSInt();
345   else if (Kind == ComplexFloat)
346     ((ComplexAPFloat*)(char*)Data.buffer)->~ComplexAPFloat();
347   else if (Kind == LValue)
348     ((LV*)(char*)Data.buffer)->~LV();
349   else if (Kind == Array)
350     ((Arr*)(char*)Data.buffer)->~Arr();
351   else if (Kind == Struct)
352     ((StructData*)(char*)Data.buffer)->~StructData();
353   else if (Kind == Union)
354     ((UnionData*)(char*)Data.buffer)->~UnionData();
355   else if (Kind == MemberPointer)
356     ((MemberPointerData*)(char*)Data.buffer)->~MemberPointerData();
357   else if (Kind == AddrLabelDiff)
358     ((AddrLabelDiffData*)(char*)Data.buffer)->~AddrLabelDiffData();
359   Kind = None;
360 }
361 
362 bool APValue::needsCleanup() const {
363   switch (getKind()) {
364   case None:
365   case Indeterminate:
366   case AddrLabelDiff:
367     return false;
368   case Struct:
369   case Union:
370   case Array:
371   case Vector:
372     return true;
373   case Int:
374     return getInt().needsCleanup();
375   case Float:
376     return getFloat().needsCleanup();
377   case FixedPoint:
378     return getFixedPoint().getValue().needsCleanup();
379   case ComplexFloat:
380     assert(getComplexFloatImag().needsCleanup() ==
381                getComplexFloatReal().needsCleanup() &&
382            "In _Complex float types, real and imaginary values always have the "
383            "same size.");
384     return getComplexFloatReal().needsCleanup();
385   case ComplexInt:
386     assert(getComplexIntImag().needsCleanup() ==
387                getComplexIntReal().needsCleanup() &&
388            "In _Complex int types, real and imaginary values must have the "
389            "same size.");
390     return getComplexIntReal().needsCleanup();
391   case LValue:
392     return reinterpret_cast<const LV *>(Data.buffer)->hasPathPtr();
393   case MemberPointer:
394     return reinterpret_cast<const MemberPointerData *>(Data.buffer)
395         ->hasPathPtr();
396   }
397   llvm_unreachable("Unknown APValue kind!");
398 }
399 
400 void APValue::swap(APValue &RHS) {
401   std::swap(Kind, RHS.Kind);
402   std::swap(Data, RHS.Data);
403 }
404 
405 static double GetApproxValue(const llvm::APFloat &F) {
406   llvm::APFloat V = F;
407   bool ignored;
408   V.convert(llvm::APFloat::IEEEdouble(), llvm::APFloat::rmNearestTiesToEven,
409             &ignored);
410   return V.convertToDouble();
411 }
412 
413 void APValue::printPretty(raw_ostream &Out, const ASTContext &Ctx,
414                           QualType Ty) const {
415   // There are no objects of type 'void', but values of this type can be
416   // returned from functions.
417   if (Ty->isVoidType()) {
418     Out << "void()";
419     return;
420   }
421 
422   switch (getKind()) {
423   case APValue::None:
424     Out << "<out of lifetime>";
425     return;
426   case APValue::Indeterminate:
427     Out << "<uninitialized>";
428     return;
429   case APValue::Int:
430     if (Ty->isBooleanType())
431       Out << (getInt().getBoolValue() ? "true" : "false");
432     else
433       Out << getInt();
434     return;
435   case APValue::Float:
436     Out << GetApproxValue(getFloat());
437     return;
438   case APValue::FixedPoint:
439     Out << getFixedPoint();
440     return;
441   case APValue::Vector: {
442     Out << '{';
443     QualType ElemTy = Ty->castAs<VectorType>()->getElementType();
444     getVectorElt(0).printPretty(Out, Ctx, ElemTy);
445     for (unsigned i = 1; i != getVectorLength(); ++i) {
446       Out << ", ";
447       getVectorElt(i).printPretty(Out, Ctx, ElemTy);
448     }
449     Out << '}';
450     return;
451   }
452   case APValue::ComplexInt:
453     Out << getComplexIntReal() << "+" << getComplexIntImag() << "i";
454     return;
455   case APValue::ComplexFloat:
456     Out << GetApproxValue(getComplexFloatReal()) << "+"
457         << GetApproxValue(getComplexFloatImag()) << "i";
458     return;
459   case APValue::LValue: {
460     bool IsReference = Ty->isReferenceType();
461     QualType InnerTy
462       = IsReference ? Ty.getNonReferenceType() : Ty->getPointeeType();
463     if (InnerTy.isNull())
464       InnerTy = Ty;
465 
466     LValueBase Base = getLValueBase();
467     if (!Base) {
468       if (isNullPointer()) {
469         Out << (Ctx.getLangOpts().CPlusPlus11 ? "nullptr" : "0");
470       } else if (IsReference) {
471         Out << "*(" << InnerTy.stream(Ctx.getPrintingPolicy()) << "*)"
472             << getLValueOffset().getQuantity();
473       } else {
474         Out << "(" << Ty.stream(Ctx.getPrintingPolicy()) << ")"
475             << getLValueOffset().getQuantity();
476       }
477       return;
478     }
479 
480     if (!hasLValuePath()) {
481       // No lvalue path: just print the offset.
482       CharUnits O = getLValueOffset();
483       CharUnits S = Ctx.getTypeSizeInChars(InnerTy);
484       if (!O.isZero()) {
485         if (IsReference)
486           Out << "*(";
487         if (O % S) {
488           Out << "(char*)";
489           S = CharUnits::One();
490         }
491         Out << '&';
492       } else if (!IsReference) {
493         Out << '&';
494       }
495 
496       if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
497         Out << *VD;
498       else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
499         TI.print(Out, Ctx.getPrintingPolicy());
500       } else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
501         Out << "{*new "
502             << Base.getDynamicAllocType().stream(Ctx.getPrintingPolicy()) << "#"
503             << DA.getIndex() << "}";
504       } else {
505         assert(Base.get<const Expr *>() != nullptr &&
506                "Expecting non-null Expr");
507         Base.get<const Expr*>()->printPretty(Out, nullptr,
508                                              Ctx.getPrintingPolicy());
509       }
510 
511       if (!O.isZero()) {
512         Out << " + " << (O / S);
513         if (IsReference)
514           Out << ')';
515       }
516       return;
517     }
518 
519     // We have an lvalue path. Print it out nicely.
520     if (!IsReference)
521       Out << '&';
522     else if (isLValueOnePastTheEnd())
523       Out << "*(&";
524 
525     QualType ElemTy;
526     if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
527       Out << *VD;
528       ElemTy = VD->getType();
529     } else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
530       TI.print(Out, Ctx.getPrintingPolicy());
531       ElemTy = Base.getTypeInfoType();
532     } else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
533       Out << "{*new "
534           << Base.getDynamicAllocType().stream(Ctx.getPrintingPolicy()) << "#"
535           << DA.getIndex() << "}";
536       ElemTy = Base.getDynamicAllocType();
537     } else {
538       const Expr *E = Base.get<const Expr*>();
539       assert(E != nullptr && "Expecting non-null Expr");
540       E->printPretty(Out, nullptr, Ctx.getPrintingPolicy());
541       // FIXME: This is wrong if E is a MaterializeTemporaryExpr with an lvalue
542       // adjustment.
543       ElemTy = E->getType();
544     }
545 
546     ArrayRef<LValuePathEntry> Path = getLValuePath();
547     const CXXRecordDecl *CastToBase = nullptr;
548     for (unsigned I = 0, N = Path.size(); I != N; ++I) {
549       if (ElemTy->getAs<RecordType>()) {
550         // The lvalue refers to a class type, so the next path entry is a base
551         // or member.
552         const Decl *BaseOrMember = Path[I].getAsBaseOrMember().getPointer();
553         if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(BaseOrMember)) {
554           CastToBase = RD;
555           ElemTy = Ctx.getRecordType(RD);
556         } else {
557           const ValueDecl *VD = cast<ValueDecl>(BaseOrMember);
558           Out << ".";
559           if (CastToBase)
560             Out << *CastToBase << "::";
561           Out << *VD;
562           ElemTy = VD->getType();
563         }
564       } else {
565         // The lvalue must refer to an array.
566         Out << '[' << Path[I].getAsArrayIndex() << ']';
567         ElemTy = Ctx.getAsArrayType(ElemTy)->getElementType();
568       }
569     }
570 
571     // Handle formatting of one-past-the-end lvalues.
572     if (isLValueOnePastTheEnd()) {
573       // FIXME: If CastToBase is non-0, we should prefix the output with
574       // "(CastToBase*)".
575       Out << " + 1";
576       if (IsReference)
577         Out << ')';
578     }
579     return;
580   }
581   case APValue::Array: {
582     const ArrayType *AT = Ctx.getAsArrayType(Ty);
583     QualType ElemTy = AT->getElementType();
584     Out << '{';
585     if (unsigned N = getArrayInitializedElts()) {
586       getArrayInitializedElt(0).printPretty(Out, Ctx, ElemTy);
587       for (unsigned I = 1; I != N; ++I) {
588         Out << ", ";
589         if (I == 10) {
590           // Avoid printing out the entire contents of large arrays.
591           Out << "...";
592           break;
593         }
594         getArrayInitializedElt(I).printPretty(Out, Ctx, ElemTy);
595       }
596     }
597     Out << '}';
598     return;
599   }
600   case APValue::Struct: {
601     Out << '{';
602     const RecordDecl *RD = Ty->castAs<RecordType>()->getDecl();
603     bool First = true;
604     if (unsigned N = getStructNumBases()) {
605       const CXXRecordDecl *CD = cast<CXXRecordDecl>(RD);
606       CXXRecordDecl::base_class_const_iterator BI = CD->bases_begin();
607       for (unsigned I = 0; I != N; ++I, ++BI) {
608         assert(BI != CD->bases_end());
609         if (!First)
610           Out << ", ";
611         getStructBase(I).printPretty(Out, Ctx, BI->getType());
612         First = false;
613       }
614     }
615     for (const auto *FI : RD->fields()) {
616       if (!First)
617         Out << ", ";
618       if (FI->isUnnamedBitfield()) continue;
619       getStructField(FI->getFieldIndex()).
620         printPretty(Out, Ctx, FI->getType());
621       First = false;
622     }
623     Out << '}';
624     return;
625   }
626   case APValue::Union:
627     Out << '{';
628     if (const FieldDecl *FD = getUnionField()) {
629       Out << "." << *FD << " = ";
630       getUnionValue().printPretty(Out, Ctx, FD->getType());
631     }
632     Out << '}';
633     return;
634   case APValue::MemberPointer:
635     // FIXME: This is not enough to unambiguously identify the member in a
636     // multiple-inheritance scenario.
637     if (const ValueDecl *VD = getMemberPointerDecl()) {
638       Out << '&' << *cast<CXXRecordDecl>(VD->getDeclContext()) << "::" << *VD;
639       return;
640     }
641     Out << "0";
642     return;
643   case APValue::AddrLabelDiff:
644     Out << "&&" << getAddrLabelDiffLHS()->getLabel()->getName();
645     Out << " - ";
646     Out << "&&" << getAddrLabelDiffRHS()->getLabel()->getName();
647     return;
648   }
649   llvm_unreachable("Unknown APValue kind!");
650 }
651 
652 std::string APValue::getAsString(const ASTContext &Ctx, QualType Ty) const {
653   std::string Result;
654   llvm::raw_string_ostream Out(Result);
655   printPretty(Out, Ctx, Ty);
656   Out.flush();
657   return Result;
658 }
659 
660 bool APValue::toIntegralConstant(APSInt &Result, QualType SrcTy,
661                                  const ASTContext &Ctx) const {
662   if (isInt()) {
663     Result = getInt();
664     return true;
665   }
666 
667   if (isLValue() && isNullPointer()) {
668     Result = Ctx.MakeIntValue(Ctx.getTargetNullPointerValue(SrcTy), SrcTy);
669     return true;
670   }
671 
672   if (isLValue() && !getLValueBase()) {
673     Result = Ctx.MakeIntValue(getLValueOffset().getQuantity(), SrcTy);
674     return true;
675   }
676 
677   return false;
678 }
679 
680 const APValue::LValueBase APValue::getLValueBase() const {
681   assert(isLValue() && "Invalid accessor");
682   return ((const LV*)(const void*)Data.buffer)->Base;
683 }
684 
685 bool APValue::isLValueOnePastTheEnd() const {
686   assert(isLValue() && "Invalid accessor");
687   return ((const LV*)(const void*)Data.buffer)->IsOnePastTheEnd;
688 }
689 
690 CharUnits &APValue::getLValueOffset() {
691   assert(isLValue() && "Invalid accessor");
692   return ((LV*)(void*)Data.buffer)->Offset;
693 }
694 
695 bool APValue::hasLValuePath() const {
696   assert(isLValue() && "Invalid accessor");
697   return ((const LV*)(const char*)Data.buffer)->hasPath();
698 }
699 
700 ArrayRef<APValue::LValuePathEntry> APValue::getLValuePath() const {
701   assert(isLValue() && hasLValuePath() && "Invalid accessor");
702   const LV &LVal = *((const LV*)(const char*)Data.buffer);
703   return llvm::makeArrayRef(LVal.getPath(), LVal.PathLength);
704 }
705 
706 unsigned APValue::getLValueCallIndex() const {
707   assert(isLValue() && "Invalid accessor");
708   return ((const LV*)(const char*)Data.buffer)->Base.getCallIndex();
709 }
710 
711 unsigned APValue::getLValueVersion() const {
712   assert(isLValue() && "Invalid accessor");
713   return ((const LV*)(const char*)Data.buffer)->Base.getVersion();
714 }
715 
716 bool APValue::isNullPointer() const {
717   assert(isLValue() && "Invalid usage");
718   return ((const LV*)(const char*)Data.buffer)->IsNullPtr;
719 }
720 
721 void APValue::setLValue(LValueBase B, const CharUnits &O, NoLValuePath,
722                         bool IsNullPtr) {
723   assert(isLValue() && "Invalid accessor");
724   LV &LVal = *((LV*)(char*)Data.buffer);
725   LVal.Base = B;
726   LVal.IsOnePastTheEnd = false;
727   LVal.Offset = O;
728   LVal.resizePath((unsigned)-1);
729   LVal.IsNullPtr = IsNullPtr;
730 }
731 
732 void APValue::setLValue(LValueBase B, const CharUnits &O,
733                         ArrayRef<LValuePathEntry> Path, bool IsOnePastTheEnd,
734                         bool IsNullPtr) {
735   assert(isLValue() && "Invalid accessor");
736   LV &LVal = *((LV*)(char*)Data.buffer);
737   LVal.Base = B;
738   LVal.IsOnePastTheEnd = IsOnePastTheEnd;
739   LVal.Offset = O;
740   LVal.resizePath(Path.size());
741   memcpy(LVal.getPath(), Path.data(), Path.size() * sizeof(LValuePathEntry));
742   LVal.IsNullPtr = IsNullPtr;
743 }
744 
745 const ValueDecl *APValue::getMemberPointerDecl() const {
746   assert(isMemberPointer() && "Invalid accessor");
747   const MemberPointerData &MPD =
748       *((const MemberPointerData *)(const char *)Data.buffer);
749   return MPD.MemberAndIsDerivedMember.getPointer();
750 }
751 
752 bool APValue::isMemberPointerToDerivedMember() const {
753   assert(isMemberPointer() && "Invalid accessor");
754   const MemberPointerData &MPD =
755       *((const MemberPointerData *)(const char *)Data.buffer);
756   return MPD.MemberAndIsDerivedMember.getInt();
757 }
758 
759 ArrayRef<const CXXRecordDecl*> APValue::getMemberPointerPath() const {
760   assert(isMemberPointer() && "Invalid accessor");
761   const MemberPointerData &MPD =
762       *((const MemberPointerData *)(const char *)Data.buffer);
763   return llvm::makeArrayRef(MPD.getPath(), MPD.PathLength);
764 }
765 
766 void APValue::MakeLValue() {
767   assert(isAbsent() && "Bad state change");
768   static_assert(sizeof(LV) <= DataSize, "LV too big");
769   new ((void*)(char*)Data.buffer) LV();
770   Kind = LValue;
771 }
772 
773 void APValue::MakeArray(unsigned InitElts, unsigned Size) {
774   assert(isAbsent() && "Bad state change");
775   new ((void*)(char*)Data.buffer) Arr(InitElts, Size);
776   Kind = Array;
777 }
778 
779 void APValue::MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
780                                 ArrayRef<const CXXRecordDecl*> Path) {
781   assert(isAbsent() && "Bad state change");
782   MemberPointerData *MPD = new ((void*)(char*)Data.buffer) MemberPointerData;
783   Kind = MemberPointer;
784   MPD->MemberAndIsDerivedMember.setPointer(
785       Member ? cast<ValueDecl>(Member->getCanonicalDecl()) : nullptr);
786   MPD->MemberAndIsDerivedMember.setInt(IsDerivedMember);
787   MPD->resizePath(Path.size());
788   for (unsigned I = 0; I != Path.size(); ++I)
789     MPD->getPath()[I] = Path[I]->getCanonicalDecl();
790 }
791