1 //===--- APValue.h - Union class for APFloat/APSInt/Complex -----*- C++ -*-===//
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 defines the APValue class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_AST_APVALUE_H
14 #define LLVM_CLANG_AST_APVALUE_H
15 
16 #include "clang/Basic/LLVM.h"
17 #include "llvm/ADT/APFixedPoint.h"
18 #include "llvm/ADT/APFloat.h"
19 #include "llvm/ADT/APSInt.h"
20 #include "llvm/ADT/FoldingSet.h"
21 #include "llvm/ADT/PointerIntPair.h"
22 #include "llvm/ADT/PointerUnion.h"
23 #include "llvm/Support/AlignOf.h"
24 
25 namespace clang {
26 namespace serialization {
27 template <typename T> class BasicReaderBase;
28 } // end namespace serialization
29 
30   class AddrLabelExpr;
31   class ASTContext;
32   class CharUnits;
33   class CXXRecordDecl;
34   class Decl;
35   class DiagnosticBuilder;
36   class Expr;
37   class FieldDecl;
38   struct PrintingPolicy;
39   class Type;
40   class ValueDecl;
41   class QualType;
42 
43 /// Symbolic representation of typeid(T) for some type T.
44 class TypeInfoLValue {
45   const Type *T;
46 
47 public:
TypeInfoLValue()48   TypeInfoLValue() : T() {}
49   explicit TypeInfoLValue(const Type *T);
50 
getType()51   const Type *getType() const { return T; }
52   explicit operator bool() const { return T; }
53 
getOpaqueValue()54   void *getOpaqueValue() { return const_cast<Type*>(T); }
getFromOpaqueValue(void * Value)55   static TypeInfoLValue getFromOpaqueValue(void *Value) {
56     TypeInfoLValue V;
57     V.T = reinterpret_cast<const Type*>(Value);
58     return V;
59   }
60 
61   void print(llvm::raw_ostream &Out, const PrintingPolicy &Policy) const;
62 };
63 
64 /// Symbolic representation of a dynamic allocation.
65 class DynamicAllocLValue {
66   unsigned Index;
67 
68 public:
DynamicAllocLValue()69   DynamicAllocLValue() : Index(0) {}
DynamicAllocLValue(unsigned Index)70   explicit DynamicAllocLValue(unsigned Index) : Index(Index + 1) {}
getIndex()71   unsigned getIndex() { return Index - 1; }
72 
73   explicit operator bool() const { return Index != 0; }
74 
getOpaqueValue()75   void *getOpaqueValue() {
76     return reinterpret_cast<void *>(static_cast<uintptr_t>(Index)
77                                     << NumLowBitsAvailable);
78   }
getFromOpaqueValue(void * Value)79   static DynamicAllocLValue getFromOpaqueValue(void *Value) {
80     DynamicAllocLValue V;
81     V.Index = reinterpret_cast<uintptr_t>(Value) >> NumLowBitsAvailable;
82     return V;
83   }
84 
getMaxIndex()85   static unsigned getMaxIndex() {
86     return (std::numeric_limits<unsigned>::max() >> NumLowBitsAvailable) - 1;
87   }
88 
89   static constexpr int NumLowBitsAvailable = 3;
90 };
91 }
92 
93 namespace llvm {
94 template<> struct PointerLikeTypeTraits<clang::TypeInfoLValue> {
95   static void *getAsVoidPointer(clang::TypeInfoLValue V) {
96     return V.getOpaqueValue();
97   }
98   static clang::TypeInfoLValue getFromVoidPointer(void *P) {
99     return clang::TypeInfoLValue::getFromOpaqueValue(P);
100   }
101   // Validated by static_assert in APValue.cpp; hardcoded to avoid needing
102   // to include Type.h.
103   static constexpr int NumLowBitsAvailable = 3;
104 };
105 
106 template<> struct PointerLikeTypeTraits<clang::DynamicAllocLValue> {
107   static void *getAsVoidPointer(clang::DynamicAllocLValue V) {
108     return V.getOpaqueValue();
109   }
110   static clang::DynamicAllocLValue getFromVoidPointer(void *P) {
111     return clang::DynamicAllocLValue::getFromOpaqueValue(P);
112   }
113   static constexpr int NumLowBitsAvailable =
114       clang::DynamicAllocLValue::NumLowBitsAvailable;
115 };
116 }
117 
118 namespace clang {
119 /// APValue - This class implements a discriminated union of [uninitialized]
120 /// [APSInt] [APFloat], [Complex APSInt] [Complex APFloat], [Expr + Offset],
121 /// [Vector: N * APValue], [Array: N * APValue]
122 class APValue {
123   typedef llvm::APFixedPoint APFixedPoint;
124   typedef llvm::APSInt APSInt;
125   typedef llvm::APFloat APFloat;
126 public:
127   enum ValueKind {
128     /// There is no such object (it's outside its lifetime).
129     None,
130     /// This object has an indeterminate value (C++ [basic.indet]).
131     Indeterminate,
132     Int,
133     Float,
134     FixedPoint,
135     ComplexInt,
136     ComplexFloat,
137     LValue,
138     Vector,
139     Array,
140     Struct,
141     Union,
142     MemberPointer,
143     AddrLabelDiff
144   };
145 
146   class LValueBase {
147     typedef llvm::PointerUnion<const ValueDecl *, const Expr *, TypeInfoLValue,
148                                DynamicAllocLValue>
149         PtrTy;
150 
151   public:
152     LValueBase() : Local{} {}
153     LValueBase(const ValueDecl *P, unsigned I = 0, unsigned V = 0);
154     LValueBase(const Expr *P, unsigned I = 0, unsigned V = 0);
155     static LValueBase getDynamicAlloc(DynamicAllocLValue LV, QualType Type);
156     static LValueBase getTypeInfo(TypeInfoLValue LV, QualType TypeInfo);
157 
158     void Profile(llvm::FoldingSetNodeID &ID) const;
159 
160     template <class T>
161     bool is() const { return Ptr.is<T>(); }
162 
163     template <class T>
164     T get() const { return Ptr.get<T>(); }
165 
166     template <class T>
167     T dyn_cast() const { return Ptr.dyn_cast<T>(); }
168 
169     void *getOpaqueValue() const;
170 
171     bool isNull() const;
172 
173     explicit operator bool() const;
174 
175     unsigned getCallIndex() const;
176     unsigned getVersion() const;
177     QualType getTypeInfoType() const;
178     QualType getDynamicAllocType() const;
179 
180     QualType getType() const;
181 
182     friend bool operator==(const LValueBase &LHS, const LValueBase &RHS);
183     friend bool operator!=(const LValueBase &LHS, const LValueBase &RHS) {
184       return !(LHS == RHS);
185     }
186     friend llvm::hash_code hash_value(const LValueBase &Base);
187     friend struct llvm::DenseMapInfo<LValueBase>;
188 
189   private:
190     PtrTy Ptr;
191     struct LocalState {
192       unsigned CallIndex, Version;
193     };
194     union {
195       LocalState Local;
196       /// The type std::type_info, if this is a TypeInfoLValue.
197       void *TypeInfoType;
198       /// The QualType, if this is a DynamicAllocLValue.
199       void *DynamicAllocType;
200     };
201   };
202 
203   /// A FieldDecl or CXXRecordDecl, along with a flag indicating whether we
204   /// mean a virtual or non-virtual base class subobject.
205   typedef llvm::PointerIntPair<const Decl *, 1, bool> BaseOrMemberType;
206 
207   /// A non-discriminated union of a base, field, or array index.
208   class LValuePathEntry {
209     static_assert(sizeof(uintptr_t) <= sizeof(uint64_t),
210                   "pointer doesn't fit in 64 bits?");
211     uint64_t Value;
212 
213   public:
214     LValuePathEntry() : Value() {}
215     LValuePathEntry(BaseOrMemberType BaseOrMember);
216     static LValuePathEntry ArrayIndex(uint64_t Index) {
217       LValuePathEntry Result;
218       Result.Value = Index;
219       return Result;
220     }
221 
222     BaseOrMemberType getAsBaseOrMember() const {
223       return BaseOrMemberType::getFromOpaqueValue(
224           reinterpret_cast<void *>(Value));
225     }
226     uint64_t getAsArrayIndex() const { return Value; }
227 
228     void Profile(llvm::FoldingSetNodeID &ID) const;
229 
230     friend bool operator==(LValuePathEntry A, LValuePathEntry B) {
231       return A.Value == B.Value;
232     }
233     friend bool operator!=(LValuePathEntry A, LValuePathEntry B) {
234       return A.Value != B.Value;
235     }
236     friend llvm::hash_code hash_value(LValuePathEntry A) {
237       return llvm::hash_value(A.Value);
238     }
239   };
240   class LValuePathSerializationHelper {
241     const void *ElemTy;
242 
243   public:
244     ArrayRef<LValuePathEntry> Path;
245 
246     LValuePathSerializationHelper(ArrayRef<LValuePathEntry>, QualType);
247     QualType getType();
248   };
249   struct NoLValuePath {};
250   struct UninitArray {};
251   struct UninitStruct {};
252 
253   template <typename Impl> friend class clang::serialization::BasicReaderBase;
254   friend class ASTImporter;
255   friend class ASTNodeImporter;
256 
257 private:
258   ValueKind Kind;
259 
260   struct ComplexAPSInt {
261     APSInt Real, Imag;
262     ComplexAPSInt() : Real(1), Imag(1) {}
263   };
264   struct ComplexAPFloat {
265     APFloat Real, Imag;
266     ComplexAPFloat() : Real(0.0), Imag(0.0) {}
267   };
268   struct LV;
269   struct Vec {
270     APValue *Elts;
271     unsigned NumElts;
272     Vec() : Elts(nullptr), NumElts(0) {}
273     ~Vec() { delete[] Elts; }
274   };
275   struct Arr {
276     APValue *Elts;
277     unsigned NumElts, ArrSize;
278     Arr(unsigned NumElts, unsigned ArrSize);
279     ~Arr();
280   };
281   struct StructData {
282     APValue *Elts;
283     unsigned NumBases;
284     unsigned NumFields;
285     StructData(unsigned NumBases, unsigned NumFields);
286     ~StructData();
287   };
288   struct UnionData {
289     const FieldDecl *Field;
290     APValue *Value;
291     UnionData();
292     ~UnionData();
293   };
294   struct AddrLabelDiffData {
295     const AddrLabelExpr* LHSExpr;
296     const AddrLabelExpr* RHSExpr;
297   };
298   struct MemberPointerData;
299 
300   // We ensure elsewhere that Data is big enough for LV and MemberPointerData.
301   typedef llvm::AlignedCharArrayUnion<void *, APSInt, APFloat, ComplexAPSInt,
302                                       ComplexAPFloat, Vec, Arr, StructData,
303                                       UnionData, AddrLabelDiffData> DataType;
304   static const size_t DataSize = sizeof(DataType);
305 
306   DataType Data;
307 
308 public:
309   APValue() : Kind(None) {}
310   explicit APValue(APSInt I) : Kind(None) {
311     MakeInt(); setInt(std::move(I));
312   }
313   explicit APValue(APFloat F) : Kind(None) {
314     MakeFloat(); setFloat(std::move(F));
315   }
316   explicit APValue(APFixedPoint FX) : Kind(None) {
317     MakeFixedPoint(std::move(FX));
318   }
319   explicit APValue(const APValue *E, unsigned N) : Kind(None) {
320     MakeVector(); setVector(E, N);
321   }
322   APValue(APSInt R, APSInt I) : Kind(None) {
323     MakeComplexInt(); setComplexInt(std::move(R), std::move(I));
324   }
325   APValue(APFloat R, APFloat I) : Kind(None) {
326     MakeComplexFloat(); setComplexFloat(std::move(R), std::move(I));
327   }
328   APValue(const APValue &RHS);
329   APValue(APValue &&RHS);
330   APValue(LValueBase B, const CharUnits &O, NoLValuePath N,
331           bool IsNullPtr = false)
332       : Kind(None) {
333     MakeLValue(); setLValue(B, O, N, IsNullPtr);
334   }
335   APValue(LValueBase B, const CharUnits &O, ArrayRef<LValuePathEntry> Path,
336           bool OnePastTheEnd, bool IsNullPtr = false)
337       : Kind(None) {
338     MakeLValue(); setLValue(B, O, Path, OnePastTheEnd, IsNullPtr);
339   }
340   APValue(UninitArray, unsigned InitElts, unsigned Size) : Kind(None) {
341     MakeArray(InitElts, Size);
342   }
343   APValue(UninitStruct, unsigned B, unsigned M) : Kind(None) {
344     MakeStruct(B, M);
345   }
346   explicit APValue(const FieldDecl *D, const APValue &V = APValue())
347       : Kind(None) {
348     MakeUnion(); setUnion(D, V);
349   }
350   APValue(const ValueDecl *Member, bool IsDerivedMember,
351           ArrayRef<const CXXRecordDecl*> Path) : Kind(None) {
352     MakeMemberPointer(Member, IsDerivedMember, Path);
353   }
354   APValue(const AddrLabelExpr* LHSExpr, const AddrLabelExpr* RHSExpr)
355       : Kind(None) {
356     MakeAddrLabelDiff(); setAddrLabelDiff(LHSExpr, RHSExpr);
357   }
358   static APValue IndeterminateValue() {
359     APValue Result;
360     Result.Kind = Indeterminate;
361     return Result;
362   }
363 
364   APValue &operator=(const APValue &RHS);
365   APValue &operator=(APValue &&RHS);
366 
367   ~APValue() {
368     if (Kind != None && Kind != Indeterminate)
369       DestroyDataAndMakeUninit();
370   }
371 
372   /// Returns whether the object performed allocations.
373   ///
374   /// If APValues are constructed via placement new, \c needsCleanup()
375   /// indicates whether the destructor must be called in order to correctly
376   /// free all allocated memory.
377   bool needsCleanup() const;
378 
379   /// Swaps the contents of this and the given APValue.
380   void swap(APValue &RHS);
381 
382   /// profile this value. There is no guarantee that values of different
383   /// types will not produce the same profiled value, so the type should
384   /// typically also be profiled if it's not implied by the context.
385   void Profile(llvm::FoldingSetNodeID &ID) const;
386 
387   ValueKind getKind() const { return Kind; }
388 
389   bool isAbsent() const { return Kind == None; }
390   bool isIndeterminate() const { return Kind == Indeterminate; }
391   bool hasValue() const { return Kind != None && Kind != Indeterminate; }
392 
393   bool isInt() const { return Kind == Int; }
394   bool isFloat() const { return Kind == Float; }
395   bool isFixedPoint() const { return Kind == FixedPoint; }
396   bool isComplexInt() const { return Kind == ComplexInt; }
397   bool isComplexFloat() const { return Kind == ComplexFloat; }
398   bool isLValue() const { return Kind == LValue; }
399   bool isVector() const { return Kind == Vector; }
400   bool isArray() const { return Kind == Array; }
401   bool isStruct() const { return Kind == Struct; }
402   bool isUnion() const { return Kind == Union; }
403   bool isMemberPointer() const { return Kind == MemberPointer; }
404   bool isAddrLabelDiff() const { return Kind == AddrLabelDiff; }
405 
406   void dump() const;
407   void dump(raw_ostream &OS, const ASTContext &Context) const;
408 
409   void printPretty(raw_ostream &OS, const ASTContext &Ctx, QualType Ty) const;
410   void printPretty(raw_ostream &OS, const PrintingPolicy &Policy, QualType Ty,
411                    const ASTContext *Ctx = nullptr) const;
412 
413   std::string getAsString(const ASTContext &Ctx, QualType Ty) const;
414 
415   APSInt &getInt() {
416     assert(isInt() && "Invalid accessor");
417     return *(APSInt *)(char *)&Data;
418   }
419   const APSInt &getInt() const {
420     return const_cast<APValue*>(this)->getInt();
421   }
422 
423   /// Try to convert this value to an integral constant. This works if it's an
424   /// integer, null pointer, or offset from a null pointer. Returns true on
425   /// success.
426   bool toIntegralConstant(APSInt &Result, QualType SrcTy,
427                           const ASTContext &Ctx) const;
428 
429   APFloat &getFloat() {
430     assert(isFloat() && "Invalid accessor");
431     return *(APFloat *)(char *)&Data;
432   }
433   const APFloat &getFloat() const {
434     return const_cast<APValue*>(this)->getFloat();
435   }
436 
437   APFixedPoint &getFixedPoint() {
438     assert(isFixedPoint() && "Invalid accessor");
439     return *(APFixedPoint *)(char *)&Data;
440   }
441   const APFixedPoint &getFixedPoint() const {
442     return const_cast<APValue *>(this)->getFixedPoint();
443   }
444 
445   APSInt &getComplexIntReal() {
446     assert(isComplexInt() && "Invalid accessor");
447     return ((ComplexAPSInt *)(char *)&Data)->Real;
448   }
449   const APSInt &getComplexIntReal() const {
450     return const_cast<APValue*>(this)->getComplexIntReal();
451   }
452 
453   APSInt &getComplexIntImag() {
454     assert(isComplexInt() && "Invalid accessor");
455     return ((ComplexAPSInt *)(char *)&Data)->Imag;
456   }
457   const APSInt &getComplexIntImag() const {
458     return const_cast<APValue*>(this)->getComplexIntImag();
459   }
460 
461   APFloat &getComplexFloatReal() {
462     assert(isComplexFloat() && "Invalid accessor");
463     return ((ComplexAPFloat *)(char *)&Data)->Real;
464   }
465   const APFloat &getComplexFloatReal() const {
466     return const_cast<APValue*>(this)->getComplexFloatReal();
467   }
468 
469   APFloat &getComplexFloatImag() {
470     assert(isComplexFloat() && "Invalid accessor");
471     return ((ComplexAPFloat *)(char *)&Data)->Imag;
472   }
473   const APFloat &getComplexFloatImag() const {
474     return const_cast<APValue*>(this)->getComplexFloatImag();
475   }
476 
477   const LValueBase getLValueBase() const;
478   CharUnits &getLValueOffset();
479   const CharUnits &getLValueOffset() const {
480     return const_cast<APValue*>(this)->getLValueOffset();
481   }
482   bool isLValueOnePastTheEnd() const;
483   bool hasLValuePath() const;
484   ArrayRef<LValuePathEntry> getLValuePath() const;
485   unsigned getLValueCallIndex() const;
486   unsigned getLValueVersion() const;
487   bool isNullPointer() const;
488 
489   APValue &getVectorElt(unsigned I) {
490     assert(isVector() && "Invalid accessor");
491     assert(I < getVectorLength() && "Index out of range");
492     return ((Vec *)(char *)&Data)->Elts[I];
493   }
494   const APValue &getVectorElt(unsigned I) const {
495     return const_cast<APValue*>(this)->getVectorElt(I);
496   }
497   unsigned getVectorLength() const {
498     assert(isVector() && "Invalid accessor");
499     return ((const Vec *)(const void *)&Data)->NumElts;
500   }
501 
502   APValue &getArrayInitializedElt(unsigned I) {
503     assert(isArray() && "Invalid accessor");
504     assert(I < getArrayInitializedElts() && "Index out of range");
505     return ((Arr *)(char *)&Data)->Elts[I];
506   }
507   const APValue &getArrayInitializedElt(unsigned I) const {
508     return const_cast<APValue*>(this)->getArrayInitializedElt(I);
509   }
510   bool hasArrayFiller() const {
511     return getArrayInitializedElts() != getArraySize();
512   }
513   APValue &getArrayFiller() {
514     assert(isArray() && "Invalid accessor");
515     assert(hasArrayFiller() && "No array filler");
516     return ((Arr *)(char *)&Data)->Elts[getArrayInitializedElts()];
517   }
518   const APValue &getArrayFiller() const {
519     return const_cast<APValue*>(this)->getArrayFiller();
520   }
521   unsigned getArrayInitializedElts() const {
522     assert(isArray() && "Invalid accessor");
523     return ((const Arr *)(const void *)&Data)->NumElts;
524   }
525   unsigned getArraySize() const {
526     assert(isArray() && "Invalid accessor");
527     return ((const Arr *)(const void *)&Data)->ArrSize;
528   }
529 
530   unsigned getStructNumBases() const {
531     assert(isStruct() && "Invalid accessor");
532     return ((const StructData *)(const char *)&Data)->NumBases;
533   }
534   unsigned getStructNumFields() const {
535     assert(isStruct() && "Invalid accessor");
536     return ((const StructData *)(const char *)&Data)->NumFields;
537   }
538   APValue &getStructBase(unsigned i) {
539     assert(isStruct() && "Invalid accessor");
540     assert(i < getStructNumBases() && "base class index OOB");
541     return ((StructData *)(char *)&Data)->Elts[i];
542   }
543   APValue &getStructField(unsigned i) {
544     assert(isStruct() && "Invalid accessor");
545     assert(i < getStructNumFields() && "field index OOB");
546     return ((StructData *)(char *)&Data)->Elts[getStructNumBases() + i];
547   }
548   const APValue &getStructBase(unsigned i) const {
549     return const_cast<APValue*>(this)->getStructBase(i);
550   }
551   const APValue &getStructField(unsigned i) const {
552     return const_cast<APValue*>(this)->getStructField(i);
553   }
554 
555   const FieldDecl *getUnionField() const {
556     assert(isUnion() && "Invalid accessor");
557     return ((const UnionData *)(const char *)&Data)->Field;
558   }
559   APValue &getUnionValue() {
560     assert(isUnion() && "Invalid accessor");
561     return *((UnionData *)(char *)&Data)->Value;
562   }
563   const APValue &getUnionValue() const {
564     return const_cast<APValue*>(this)->getUnionValue();
565   }
566 
567   const ValueDecl *getMemberPointerDecl() const;
568   bool isMemberPointerToDerivedMember() const;
569   ArrayRef<const CXXRecordDecl*> getMemberPointerPath() const;
570 
571   const AddrLabelExpr* getAddrLabelDiffLHS() const {
572     assert(isAddrLabelDiff() && "Invalid accessor");
573     return ((const AddrLabelDiffData *)(const char *)&Data)->LHSExpr;
574   }
575   const AddrLabelExpr* getAddrLabelDiffRHS() const {
576     assert(isAddrLabelDiff() && "Invalid accessor");
577     return ((const AddrLabelDiffData *)(const char *)&Data)->RHSExpr;
578   }
579 
580   void setInt(APSInt I) {
581     assert(isInt() && "Invalid accessor");
582     *(APSInt *)(char *)&Data = std::move(I);
583   }
584   void setFloat(APFloat F) {
585     assert(isFloat() && "Invalid accessor");
586     *(APFloat *)(char *)&Data = std::move(F);
587   }
588   void setFixedPoint(APFixedPoint FX) {
589     assert(isFixedPoint() && "Invalid accessor");
590     *(APFixedPoint *)(char *)&Data = std::move(FX);
591   }
592   void setVector(const APValue *E, unsigned N) {
593     MutableArrayRef<APValue> InternalElts = setVectorUninit(N);
594     for (unsigned i = 0; i != N; ++i)
595       InternalElts[i] = E[i];
596   }
597   void setComplexInt(APSInt R, APSInt I) {
598     assert(R.getBitWidth() == I.getBitWidth() &&
599            "Invalid complex int (type mismatch).");
600     assert(isComplexInt() && "Invalid accessor");
601     ((ComplexAPSInt *)(char *)&Data)->Real = std::move(R);
602     ((ComplexAPSInt *)(char *)&Data)->Imag = std::move(I);
603   }
604   void setComplexFloat(APFloat R, APFloat I) {
605     assert(&R.getSemantics() == &I.getSemantics() &&
606            "Invalid complex float (type mismatch).");
607     assert(isComplexFloat() && "Invalid accessor");
608     ((ComplexAPFloat *)(char *)&Data)->Real = std::move(R);
609     ((ComplexAPFloat *)(char *)&Data)->Imag = std::move(I);
610   }
611   void setLValue(LValueBase B, const CharUnits &O, NoLValuePath,
612                  bool IsNullPtr);
613   void setLValue(LValueBase B, const CharUnits &O,
614                  ArrayRef<LValuePathEntry> Path, bool OnePastTheEnd,
615                  bool IsNullPtr);
616   void setUnion(const FieldDecl *Field, const APValue &Value);
617   void setAddrLabelDiff(const AddrLabelExpr* LHSExpr,
618                         const AddrLabelExpr* RHSExpr) {
619     ((AddrLabelDiffData *)(char *)&Data)->LHSExpr = LHSExpr;
620     ((AddrLabelDiffData *)(char *)&Data)->RHSExpr = RHSExpr;
621   }
622 
623 private:
624   void DestroyDataAndMakeUninit();
625   void MakeInt() {
626     assert(isAbsent() && "Bad state change");
627     new ((void *)&Data) APSInt(1);
628     Kind = Int;
629   }
630   void MakeFloat() {
631     assert(isAbsent() && "Bad state change");
632     new ((void *)(char *)&Data) APFloat(0.0);
633     Kind = Float;
634   }
635   void MakeFixedPoint(APFixedPoint &&FX) {
636     assert(isAbsent() && "Bad state change");
637     new ((void *)(char *)&Data) APFixedPoint(std::move(FX));
638     Kind = FixedPoint;
639   }
640   void MakeVector() {
641     assert(isAbsent() && "Bad state change");
642     new ((void *)(char *)&Data) Vec();
643     Kind = Vector;
644   }
645   void MakeComplexInt() {
646     assert(isAbsent() && "Bad state change");
647     new ((void *)(char *)&Data) ComplexAPSInt();
648     Kind = ComplexInt;
649   }
650   void MakeComplexFloat() {
651     assert(isAbsent() && "Bad state change");
652     new ((void *)(char *)&Data) ComplexAPFloat();
653     Kind = ComplexFloat;
654   }
655   void MakeLValue();
656   void MakeArray(unsigned InitElts, unsigned Size);
657   void MakeStruct(unsigned B, unsigned M) {
658     assert(isAbsent() && "Bad state change");
659     new ((void *)(char *)&Data) StructData(B, M);
660     Kind = Struct;
661   }
662   void MakeUnion() {
663     assert(isAbsent() && "Bad state change");
664     new ((void *)(char *)&Data) UnionData();
665     Kind = Union;
666   }
667   void MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
668                          ArrayRef<const CXXRecordDecl*> Path);
669   void MakeAddrLabelDiff() {
670     assert(isAbsent() && "Bad state change");
671     new ((void *)(char *)&Data) AddrLabelDiffData();
672     Kind = AddrLabelDiff;
673   }
674 
675 private:
676   /// The following functions are used as part of initialization, during
677   /// deserialization and importing. Reserve the space so that it can be
678   /// filled in by those steps.
679   MutableArrayRef<APValue> setVectorUninit(unsigned N) {
680     assert(isVector() && "Invalid accessor");
681     Vec *V = ((Vec *)(char *)&Data);
682     V->Elts = new APValue[N];
683     V->NumElts = N;
684     return {V->Elts, V->NumElts};
685   }
686   MutableArrayRef<LValuePathEntry>
687   setLValueUninit(LValueBase B, const CharUnits &O, unsigned Size,
688                   bool OnePastTheEnd, bool IsNullPtr);
689   MutableArrayRef<const CXXRecordDecl *>
690   setMemberPointerUninit(const ValueDecl *Member, bool IsDerivedMember,
691                          unsigned Size);
692 };
693 
694 } // end namespace clang.
695 
696 namespace llvm {
697 template<> struct DenseMapInfo<clang::APValue::LValueBase> {
698   static clang::APValue::LValueBase getEmptyKey();
699   static clang::APValue::LValueBase getTombstoneKey();
700   static unsigned getHashValue(const clang::APValue::LValueBase &Base);
701   static bool isEqual(const clang::APValue::LValueBase &LHS,
702                       const clang::APValue::LValueBase &RHS);
703 };
704 }
705 
706 #endif
707