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 "Linkage.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/CharUnits.h"
17 #include "clang/AST/DeclCXX.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/ExprCXX.h"
20 #include "clang/AST/Type.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/raw_ostream.h"
23 using namespace clang;
24 
25 /// The identity of a type_info object depends on the canonical unqualified
26 /// type only.
27 TypeInfoLValue::TypeInfoLValue(const Type *T)
28     : T(T->getCanonicalTypeUnqualified().getTypePtr()) {}
29 
30 void TypeInfoLValue::print(llvm::raw_ostream &Out,
31                            const PrintingPolicy &Policy) const {
32   Out << "typeid(";
33   QualType(getType(), 0).print(Out, Policy);
34   Out << ")";
35 }
36 
37 static_assert(
38     1 << llvm::PointerLikeTypeTraits<TypeInfoLValue>::NumLowBitsAvailable <=
39         alignof(Type),
40     "Type is insufficiently aligned");
41 
42 APValue::LValueBase::LValueBase(const ValueDecl *P, unsigned I, unsigned V)
43     : Ptr(P ? cast<ValueDecl>(P->getCanonicalDecl()) : nullptr), Local{I, V} {}
44 APValue::LValueBase::LValueBase(const Expr *P, unsigned I, unsigned V)
45     : Ptr(P), Local{I, V} {}
46 
47 APValue::LValueBase APValue::LValueBase::getDynamicAlloc(DynamicAllocLValue LV,
48                                                          QualType Type) {
49   LValueBase Base;
50   Base.Ptr = LV;
51   Base.DynamicAllocType = Type.getAsOpaquePtr();
52   return Base;
53 }
54 
55 APValue::LValueBase APValue::LValueBase::getTypeInfo(TypeInfoLValue LV,
56                                                      QualType TypeInfo) {
57   LValueBase Base;
58   Base.Ptr = LV;
59   Base.TypeInfoType = TypeInfo.getAsOpaquePtr();
60   return Base;
61 }
62 
63 QualType APValue::LValueBase::getType() const {
64   if (!*this) return QualType();
65   if (const ValueDecl *D = dyn_cast<const ValueDecl*>()) {
66     // FIXME: It's unclear where we're supposed to take the type from, and
67     // this actually matters for arrays of unknown bound. Eg:
68     //
69     // extern int arr[]; void f() { extern int arr[3]; };
70     // constexpr int *p = &arr[1]; // valid?
71     //
72     // For now, we take the most complete type we can find.
73     for (auto *Redecl = cast<ValueDecl>(D->getMostRecentDecl()); Redecl;
74          Redecl = cast_or_null<ValueDecl>(Redecl->getPreviousDecl())) {
75       QualType T = Redecl->getType();
76       if (!T->isIncompleteArrayType())
77         return T;
78     }
79     return D->getType();
80   }
81 
82   if (is<TypeInfoLValue>())
83     return getTypeInfoType();
84 
85   if (is<DynamicAllocLValue>())
86     return getDynamicAllocType();
87 
88   const Expr *Base = get<const Expr*>();
89 
90   // For a materialized temporary, the type of the temporary we materialized
91   // may not be the type of the expression.
92   if (const MaterializeTemporaryExpr *MTE =
93           clang::dyn_cast<MaterializeTemporaryExpr>(Base)) {
94     SmallVector<const Expr *, 2> CommaLHSs;
95     SmallVector<SubobjectAdjustment, 2> Adjustments;
96     const Expr *Temp = MTE->getSubExpr();
97     const Expr *Inner = Temp->skipRValueSubobjectAdjustments(CommaLHSs,
98                                                              Adjustments);
99     // Keep any cv-qualifiers from the reference if we generated a temporary
100     // for it directly. Otherwise use the type after adjustment.
101     if (!Adjustments.empty())
102       return Inner->getType();
103   }
104 
105   return Base->getType();
106 }
107 
108 unsigned APValue::LValueBase::getCallIndex() const {
109   return (is<TypeInfoLValue>() || is<DynamicAllocLValue>()) ? 0
110                                                             : Local.CallIndex;
111 }
112 
113 unsigned APValue::LValueBase::getVersion() const {
114   return (is<TypeInfoLValue>() || is<DynamicAllocLValue>()) ? 0 : Local.Version;
115 }
116 
117 QualType APValue::LValueBase::getTypeInfoType() const {
118   assert(is<TypeInfoLValue>() && "not a type_info lvalue");
119   return QualType::getFromOpaquePtr(TypeInfoType);
120 }
121 
122 QualType APValue::LValueBase::getDynamicAllocType() const {
123   assert(is<DynamicAllocLValue>() && "not a dynamic allocation lvalue");
124   return QualType::getFromOpaquePtr(DynamicAllocType);
125 }
126 
127 void APValue::LValueBase::Profile(llvm::FoldingSetNodeID &ID) const {
128   ID.AddPointer(Ptr.getOpaqueValue());
129   if (is<TypeInfoLValue>() || is<DynamicAllocLValue>())
130     return;
131   ID.AddInteger(Local.CallIndex);
132   ID.AddInteger(Local.Version);
133 }
134 
135 namespace clang {
136 bool operator==(const APValue::LValueBase &LHS,
137                 const APValue::LValueBase &RHS) {
138   if (LHS.Ptr != RHS.Ptr)
139     return false;
140   if (LHS.is<TypeInfoLValue>() || LHS.is<DynamicAllocLValue>())
141     return true;
142   return LHS.Local.CallIndex == RHS.Local.CallIndex &&
143          LHS.Local.Version == RHS.Local.Version;
144 }
145 }
146 
147 APValue::LValuePathEntry::LValuePathEntry(BaseOrMemberType BaseOrMember) {
148   if (const Decl *D = BaseOrMember.getPointer())
149     BaseOrMember.setPointer(D->getCanonicalDecl());
150   Value = reinterpret_cast<uintptr_t>(BaseOrMember.getOpaqueValue());
151 }
152 
153 void APValue::LValuePathEntry::Profile(llvm::FoldingSetNodeID &ID) const {
154   ID.AddInteger(Value);
155 }
156 
157 APValue::LValuePathSerializationHelper::LValuePathSerializationHelper(
158     ArrayRef<LValuePathEntry> Path, QualType ElemTy)
159     : ElemTy((const void *)ElemTy.getTypePtrOrNull()), Path(Path) {}
160 
161 QualType APValue::LValuePathSerializationHelper::getType() {
162   return QualType::getFromOpaquePtr(ElemTy);
163 }
164 
165 namespace {
166   struct LVBase {
167     APValue::LValueBase Base;
168     CharUnits Offset;
169     unsigned PathLength;
170     bool IsNullPtr : 1;
171     bool IsOnePastTheEnd : 1;
172   };
173 }
174 
175 void *APValue::LValueBase::getOpaqueValue() const {
176   return Ptr.getOpaqueValue();
177 }
178 
179 bool APValue::LValueBase::isNull() const {
180   return Ptr.isNull();
181 }
182 
183 APValue::LValueBase::operator bool () const {
184   return static_cast<bool>(Ptr);
185 }
186 
187 clang::APValue::LValueBase
188 llvm::DenseMapInfo<clang::APValue::LValueBase>::getEmptyKey() {
189   clang::APValue::LValueBase B;
190   B.Ptr = DenseMapInfo<const ValueDecl*>::getEmptyKey();
191   return B;
192 }
193 
194 clang::APValue::LValueBase
195 llvm::DenseMapInfo<clang::APValue::LValueBase>::getTombstoneKey() {
196   clang::APValue::LValueBase B;
197   B.Ptr = DenseMapInfo<const ValueDecl*>::getTombstoneKey();
198   return B;
199 }
200 
201 namespace clang {
202 llvm::hash_code hash_value(const APValue::LValueBase &Base) {
203   if (Base.is<TypeInfoLValue>() || Base.is<DynamicAllocLValue>())
204     return llvm::hash_value(Base.getOpaqueValue());
205   return llvm::hash_combine(Base.getOpaqueValue(), Base.getCallIndex(),
206                             Base.getVersion());
207 }
208 }
209 
210 unsigned llvm::DenseMapInfo<clang::APValue::LValueBase>::getHashValue(
211     const clang::APValue::LValueBase &Base) {
212   return hash_value(Base);
213 }
214 
215 bool llvm::DenseMapInfo<clang::APValue::LValueBase>::isEqual(
216     const clang::APValue::LValueBase &LHS,
217     const clang::APValue::LValueBase &RHS) {
218   return LHS == RHS;
219 }
220 
221 struct APValue::LV : LVBase {
222   static const unsigned InlinePathSpace =
223       (DataSize - sizeof(LVBase)) / sizeof(LValuePathEntry);
224 
225   /// Path - The sequence of base classes, fields and array indices to follow to
226   /// walk from Base to the subobject. When performing GCC-style folding, there
227   /// may not be such a path.
228   union {
229     LValuePathEntry Path[InlinePathSpace];
230     LValuePathEntry *PathPtr;
231   };
232 
233   LV() { PathLength = (unsigned)-1; }
234   ~LV() { resizePath(0); }
235 
236   void resizePath(unsigned Length) {
237     if (Length == PathLength)
238       return;
239     if (hasPathPtr())
240       delete [] PathPtr;
241     PathLength = Length;
242     if (hasPathPtr())
243       PathPtr = new LValuePathEntry[Length];
244   }
245 
246   bool hasPath() const { return PathLength != (unsigned)-1; }
247   bool hasPathPtr() const { return hasPath() && PathLength > InlinePathSpace; }
248 
249   LValuePathEntry *getPath() { return hasPathPtr() ? PathPtr : Path; }
250   const LValuePathEntry *getPath() const {
251     return hasPathPtr() ? PathPtr : Path;
252   }
253 };
254 
255 namespace {
256   struct MemberPointerBase {
257     llvm::PointerIntPair<const ValueDecl*, 1, bool> MemberAndIsDerivedMember;
258     unsigned PathLength;
259   };
260 }
261 
262 struct APValue::MemberPointerData : MemberPointerBase {
263   static const unsigned InlinePathSpace =
264       (DataSize - sizeof(MemberPointerBase)) / sizeof(const CXXRecordDecl*);
265   typedef const CXXRecordDecl *PathElem;
266   union {
267     PathElem Path[InlinePathSpace];
268     PathElem *PathPtr;
269   };
270 
271   MemberPointerData() { PathLength = 0; }
272   ~MemberPointerData() { resizePath(0); }
273 
274   void resizePath(unsigned Length) {
275     if (Length == PathLength)
276       return;
277     if (hasPathPtr())
278       delete [] PathPtr;
279     PathLength = Length;
280     if (hasPathPtr())
281       PathPtr = new PathElem[Length];
282   }
283 
284   bool hasPathPtr() const { return PathLength > InlinePathSpace; }
285 
286   PathElem *getPath() { return hasPathPtr() ? PathPtr : Path; }
287   const PathElem *getPath() const {
288     return hasPathPtr() ? PathPtr : Path;
289   }
290 };
291 
292 // FIXME: Reduce the malloc traffic here.
293 
294 APValue::Arr::Arr(unsigned NumElts, unsigned Size) :
295   Elts(new APValue[NumElts + (NumElts != Size ? 1 : 0)]),
296   NumElts(NumElts), ArrSize(Size) {}
297 APValue::Arr::~Arr() { delete [] Elts; }
298 
299 APValue::StructData::StructData(unsigned NumBases, unsigned NumFields) :
300   Elts(new APValue[NumBases+NumFields]),
301   NumBases(NumBases), NumFields(NumFields) {}
302 APValue::StructData::~StructData() {
303   delete [] Elts;
304 }
305 
306 APValue::UnionData::UnionData() : Field(nullptr), Value(new APValue) {}
307 APValue::UnionData::~UnionData () {
308   delete Value;
309 }
310 
311 APValue::APValue(const APValue &RHS) : Kind(None) {
312   switch (RHS.getKind()) {
313   case None:
314   case Indeterminate:
315     Kind = RHS.getKind();
316     break;
317   case Int:
318     MakeInt();
319     setInt(RHS.getInt());
320     break;
321   case Float:
322     MakeFloat();
323     setFloat(RHS.getFloat());
324     break;
325   case FixedPoint: {
326     APFixedPoint FXCopy = RHS.getFixedPoint();
327     MakeFixedPoint(std::move(FXCopy));
328     break;
329   }
330   case Vector:
331     MakeVector();
332     setVector(((const Vec *)(const char *)&RHS.Data)->Elts,
333               RHS.getVectorLength());
334     break;
335   case ComplexInt:
336     MakeComplexInt();
337     setComplexInt(RHS.getComplexIntReal(), RHS.getComplexIntImag());
338     break;
339   case ComplexFloat:
340     MakeComplexFloat();
341     setComplexFloat(RHS.getComplexFloatReal(), RHS.getComplexFloatImag());
342     break;
343   case LValue:
344     MakeLValue();
345     if (RHS.hasLValuePath())
346       setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), RHS.getLValuePath(),
347                 RHS.isLValueOnePastTheEnd(), RHS.isNullPointer());
348     else
349       setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), NoLValuePath(),
350                 RHS.isNullPointer());
351     break;
352   case Array:
353     MakeArray(RHS.getArrayInitializedElts(), RHS.getArraySize());
354     for (unsigned I = 0, N = RHS.getArrayInitializedElts(); I != N; ++I)
355       getArrayInitializedElt(I) = RHS.getArrayInitializedElt(I);
356     if (RHS.hasArrayFiller())
357       getArrayFiller() = RHS.getArrayFiller();
358     break;
359   case Struct:
360     MakeStruct(RHS.getStructNumBases(), RHS.getStructNumFields());
361     for (unsigned I = 0, N = RHS.getStructNumBases(); I != N; ++I)
362       getStructBase(I) = RHS.getStructBase(I);
363     for (unsigned I = 0, N = RHS.getStructNumFields(); I != N; ++I)
364       getStructField(I) = RHS.getStructField(I);
365     break;
366   case Union:
367     MakeUnion();
368     setUnion(RHS.getUnionField(), RHS.getUnionValue());
369     break;
370   case MemberPointer:
371     MakeMemberPointer(RHS.getMemberPointerDecl(),
372                       RHS.isMemberPointerToDerivedMember(),
373                       RHS.getMemberPointerPath());
374     break;
375   case AddrLabelDiff:
376     MakeAddrLabelDiff();
377     setAddrLabelDiff(RHS.getAddrLabelDiffLHS(), RHS.getAddrLabelDiffRHS());
378     break;
379   }
380 }
381 
382 APValue::APValue(APValue &&RHS) : Kind(RHS.Kind), Data(RHS.Data) {
383   RHS.Kind = None;
384 }
385 
386 APValue &APValue::operator=(const APValue &RHS) {
387   if (this != &RHS)
388     *this = APValue(RHS);
389   return *this;
390 }
391 
392 APValue &APValue::operator=(APValue &&RHS) {
393   if (Kind != None && Kind != Indeterminate)
394     DestroyDataAndMakeUninit();
395   Kind = RHS.Kind;
396   Data = RHS.Data;
397   RHS.Kind = None;
398   return *this;
399 }
400 
401 void APValue::DestroyDataAndMakeUninit() {
402   if (Kind == Int)
403     ((APSInt *)(char *)&Data)->~APSInt();
404   else if (Kind == Float)
405     ((APFloat *)(char *)&Data)->~APFloat();
406   else if (Kind == FixedPoint)
407     ((APFixedPoint *)(char *)&Data)->~APFixedPoint();
408   else if (Kind == Vector)
409     ((Vec *)(char *)&Data)->~Vec();
410   else if (Kind == ComplexInt)
411     ((ComplexAPSInt *)(char *)&Data)->~ComplexAPSInt();
412   else if (Kind == ComplexFloat)
413     ((ComplexAPFloat *)(char *)&Data)->~ComplexAPFloat();
414   else if (Kind == LValue)
415     ((LV *)(char *)&Data)->~LV();
416   else if (Kind == Array)
417     ((Arr *)(char *)&Data)->~Arr();
418   else if (Kind == Struct)
419     ((StructData *)(char *)&Data)->~StructData();
420   else if (Kind == Union)
421     ((UnionData *)(char *)&Data)->~UnionData();
422   else if (Kind == MemberPointer)
423     ((MemberPointerData *)(char *)&Data)->~MemberPointerData();
424   else if (Kind == AddrLabelDiff)
425     ((AddrLabelDiffData *)(char *)&Data)->~AddrLabelDiffData();
426   Kind = None;
427 }
428 
429 bool APValue::needsCleanup() const {
430   switch (getKind()) {
431   case None:
432   case Indeterminate:
433   case AddrLabelDiff:
434     return false;
435   case Struct:
436   case Union:
437   case Array:
438   case Vector:
439     return true;
440   case Int:
441     return getInt().needsCleanup();
442   case Float:
443     return getFloat().needsCleanup();
444   case FixedPoint:
445     return getFixedPoint().getValue().needsCleanup();
446   case ComplexFloat:
447     assert(getComplexFloatImag().needsCleanup() ==
448                getComplexFloatReal().needsCleanup() &&
449            "In _Complex float types, real and imaginary values always have the "
450            "same size.");
451     return getComplexFloatReal().needsCleanup();
452   case ComplexInt:
453     assert(getComplexIntImag().needsCleanup() ==
454                getComplexIntReal().needsCleanup() &&
455            "In _Complex int types, real and imaginary values must have the "
456            "same size.");
457     return getComplexIntReal().needsCleanup();
458   case LValue:
459     return reinterpret_cast<const LV *>(&Data)->hasPathPtr();
460   case MemberPointer:
461     return reinterpret_cast<const MemberPointerData *>(&Data)->hasPathPtr();
462   }
463   llvm_unreachable("Unknown APValue kind!");
464 }
465 
466 void APValue::swap(APValue &RHS) {
467   std::swap(Kind, RHS.Kind);
468   std::swap(Data, RHS.Data);
469 }
470 
471 /// Profile the value of an APInt, excluding its bit-width.
472 static void profileIntValue(llvm::FoldingSetNodeID &ID, const llvm::APInt &V) {
473   for (unsigned I = 0, N = V.getBitWidth(); I < N; I += 32)
474     ID.AddInteger((uint32_t)V.extractBitsAsZExtValue(std::min(32u, N - I), I));
475 }
476 
477 void APValue::Profile(llvm::FoldingSetNodeID &ID) const {
478   // Note that our profiling assumes that only APValues of the same type are
479   // ever compared. As a result, we don't consider collisions that could only
480   // happen if the types are different. (For example, structs with different
481   // numbers of members could profile the same.)
482 
483   ID.AddInteger(Kind);
484 
485   switch (Kind) {
486   case None:
487   case Indeterminate:
488     return;
489 
490   case AddrLabelDiff:
491     ID.AddPointer(getAddrLabelDiffLHS()->getLabel()->getCanonicalDecl());
492     ID.AddPointer(getAddrLabelDiffRHS()->getLabel()->getCanonicalDecl());
493     return;
494 
495   case Struct:
496     for (unsigned I = 0, N = getStructNumBases(); I != N; ++I)
497       getStructBase(I).Profile(ID);
498     for (unsigned I = 0, N = getStructNumFields(); I != N; ++I)
499       getStructField(I).Profile(ID);
500     return;
501 
502   case Union:
503     if (!getUnionField()) {
504       ID.AddInteger(0);
505       return;
506     }
507     ID.AddInteger(getUnionField()->getFieldIndex() + 1);
508     getUnionValue().Profile(ID);
509     return;
510 
511   case Array: {
512     if (getArraySize() == 0)
513       return;
514 
515     // The profile should not depend on whether the array is expanded or
516     // not, but we don't want to profile the array filler many times for
517     // a large array. So treat all equal trailing elements as the filler.
518     // Elements are profiled in reverse order to support this, and the
519     // first profiled element is followed by a count. For example:
520     //
521     //   ['a', 'c', 'x', 'x', 'x'] is profiled as
522     //   [5, 'x', 3, 'c', 'a']
523     llvm::FoldingSetNodeID FillerID;
524     (hasArrayFiller() ? getArrayFiller()
525                       : getArrayInitializedElt(getArrayInitializedElts() - 1))
526         .Profile(FillerID);
527     ID.AddNodeID(FillerID);
528     unsigned NumFillers = getArraySize() - getArrayInitializedElts();
529     unsigned N = getArrayInitializedElts();
530 
531     // Count the number of elements equal to the last one. This loop ends
532     // by adding an integer indicating the number of such elements, with
533     // N set to the number of elements left to profile.
534     while (true) {
535       if (N == 0) {
536         // All elements are fillers.
537         assert(NumFillers == getArraySize());
538         ID.AddInteger(NumFillers);
539         break;
540       }
541 
542       // No need to check if the last element is equal to the last
543       // element.
544       if (N != getArraySize()) {
545         llvm::FoldingSetNodeID ElemID;
546         getArrayInitializedElt(N - 1).Profile(ElemID);
547         if (ElemID != FillerID) {
548           ID.AddInteger(NumFillers);
549           ID.AddNodeID(ElemID);
550           --N;
551           break;
552         }
553       }
554 
555       // This is a filler.
556       ++NumFillers;
557       --N;
558     }
559 
560     // Emit the remaining elements.
561     for (; N != 0; --N)
562       getArrayInitializedElt(N - 1).Profile(ID);
563     return;
564   }
565 
566   case Vector:
567     for (unsigned I = 0, N = getVectorLength(); I != N; ++I)
568       getVectorElt(I).Profile(ID);
569     return;
570 
571   case Int:
572     profileIntValue(ID, getInt());
573     return;
574 
575   case Float:
576     profileIntValue(ID, getFloat().bitcastToAPInt());
577     return;
578 
579   case FixedPoint:
580     profileIntValue(ID, getFixedPoint().getValue());
581     return;
582 
583   case ComplexFloat:
584     profileIntValue(ID, getComplexFloatReal().bitcastToAPInt());
585     profileIntValue(ID, getComplexFloatImag().bitcastToAPInt());
586     return;
587 
588   case ComplexInt:
589     profileIntValue(ID, getComplexIntReal());
590     profileIntValue(ID, getComplexIntImag());
591     return;
592 
593   case LValue:
594     getLValueBase().Profile(ID);
595     ID.AddInteger(getLValueOffset().getQuantity());
596     ID.AddInteger((isNullPointer() ? 1 : 0) |
597                   (isLValueOnePastTheEnd() ? 2 : 0) |
598                   (hasLValuePath() ? 4 : 0));
599     if (hasLValuePath()) {
600       ID.AddInteger(getLValuePath().size());
601       // For uniqueness, we only need to profile the entries corresponding
602       // to union members, but we don't have the type here so we don't know
603       // how to interpret the entries.
604       for (LValuePathEntry E : getLValuePath())
605         E.Profile(ID);
606     }
607     return;
608 
609   case MemberPointer:
610     ID.AddPointer(getMemberPointerDecl());
611     ID.AddInteger(isMemberPointerToDerivedMember());
612     for (const CXXRecordDecl *D : getMemberPointerPath())
613       ID.AddPointer(D);
614     return;
615   }
616 
617   llvm_unreachable("Unknown APValue kind!");
618 }
619 
620 static double GetApproxValue(const llvm::APFloat &F) {
621   llvm::APFloat V = F;
622   bool ignored;
623   V.convert(llvm::APFloat::IEEEdouble(), llvm::APFloat::rmNearestTiesToEven,
624             &ignored);
625   return V.convertToDouble();
626 }
627 
628 static bool TryPrintAsStringLiteral(raw_ostream &Out,
629                                     const PrintingPolicy &Policy,
630                                     const ArrayType *ATy,
631                                     ArrayRef<APValue> Inits) {
632   if (Inits.empty())
633     return false;
634 
635   QualType Ty = ATy->getElementType();
636   if (!Ty->isAnyCharacterType())
637     return false;
638 
639   // Nothing we can do about a sequence that is not null-terminated
640   if (!Inits.back().getInt().isZero())
641     return false;
642   else
643     Inits = Inits.drop_back();
644 
645   llvm::SmallString<40> Buf;
646   Buf.push_back('"');
647 
648   // Better than printing a two-digit sequence of 10 integers.
649   constexpr size_t MaxN = 36;
650   StringRef Ellipsis;
651   if (Inits.size() > MaxN && !Policy.EntireContentsOfLargeArray) {
652     Ellipsis = "[...]";
653     Inits =
654         Inits.take_front(std::min(MaxN - Ellipsis.size() / 2, Inits.size()));
655   }
656 
657   for (auto &Val : Inits) {
658     int64_t Char64 = Val.getInt().getExtValue();
659     if (!isASCII(Char64))
660       return false; // Bye bye, see you in integers.
661     auto Ch = static_cast<unsigned char>(Char64);
662     // The diagnostic message is 'quoted'
663     StringRef Escaped = escapeCStyle<EscapeChar::SingleAndDouble>(Ch);
664     if (Escaped.empty()) {
665       if (!isPrintable(Ch))
666         return false;
667       Buf.emplace_back(Ch);
668     } else {
669       Buf.append(Escaped);
670     }
671   }
672 
673   Buf.append(Ellipsis);
674   Buf.push_back('"');
675 
676   if (Ty->isWideCharType())
677     Out << 'L';
678   else if (Ty->isChar8Type())
679     Out << "u8";
680   else if (Ty->isChar16Type())
681     Out << 'u';
682   else if (Ty->isChar32Type())
683     Out << 'U';
684 
685   Out << Buf;
686   return true;
687 }
688 
689 void APValue::printPretty(raw_ostream &Out, const ASTContext &Ctx,
690                           QualType Ty) const {
691   printPretty(Out, Ctx.getPrintingPolicy(), Ty, &Ctx);
692 }
693 
694 void APValue::printPretty(raw_ostream &Out, const PrintingPolicy &Policy,
695                           QualType Ty, const ASTContext *Ctx) const {
696   // There are no objects of type 'void', but values of this type can be
697   // returned from functions.
698   if (Ty->isVoidType()) {
699     Out << "void()";
700     return;
701   }
702 
703   switch (getKind()) {
704   case APValue::None:
705     Out << "<out of lifetime>";
706     return;
707   case APValue::Indeterminate:
708     Out << "<uninitialized>";
709     return;
710   case APValue::Int:
711     if (Ty->isBooleanType())
712       Out << (getInt().getBoolValue() ? "true" : "false");
713     else
714       Out << getInt();
715     return;
716   case APValue::Float:
717     Out << GetApproxValue(getFloat());
718     return;
719   case APValue::FixedPoint:
720     Out << getFixedPoint();
721     return;
722   case APValue::Vector: {
723     Out << '{';
724     QualType ElemTy = Ty->castAs<VectorType>()->getElementType();
725     getVectorElt(0).printPretty(Out, Policy, ElemTy, Ctx);
726     for (unsigned i = 1; i != getVectorLength(); ++i) {
727       Out << ", ";
728       getVectorElt(i).printPretty(Out, Policy, ElemTy, Ctx);
729     }
730     Out << '}';
731     return;
732   }
733   case APValue::ComplexInt:
734     Out << getComplexIntReal() << "+" << getComplexIntImag() << "i";
735     return;
736   case APValue::ComplexFloat:
737     Out << GetApproxValue(getComplexFloatReal()) << "+"
738         << GetApproxValue(getComplexFloatImag()) << "i";
739     return;
740   case APValue::LValue: {
741     bool IsReference = Ty->isReferenceType();
742     QualType InnerTy
743       = IsReference ? Ty.getNonReferenceType() : Ty->getPointeeType();
744     if (InnerTy.isNull())
745       InnerTy = Ty;
746 
747     LValueBase Base = getLValueBase();
748     if (!Base) {
749       if (isNullPointer()) {
750         Out << (Policy.Nullptr ? "nullptr" : "0");
751       } else if (IsReference) {
752         Out << "*(" << InnerTy.stream(Policy) << "*)"
753             << getLValueOffset().getQuantity();
754       } else {
755         Out << "(" << Ty.stream(Policy) << ")"
756             << getLValueOffset().getQuantity();
757       }
758       return;
759     }
760 
761     if (!hasLValuePath()) {
762       // No lvalue path: just print the offset.
763       CharUnits O = getLValueOffset();
764       CharUnits S = Ctx ? Ctx->getTypeSizeInCharsIfKnown(InnerTy).value_or(
765                               CharUnits::Zero())
766                         : CharUnits::Zero();
767       if (!O.isZero()) {
768         if (IsReference)
769           Out << "*(";
770         if (S.isZero() || O % S) {
771           Out << "(char*)";
772           S = CharUnits::One();
773         }
774         Out << '&';
775       } else if (!IsReference) {
776         Out << '&';
777       }
778 
779       if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
780         Out << *VD;
781       else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
782         TI.print(Out, Policy);
783       } else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
784         Out << "{*new "
785             << Base.getDynamicAllocType().stream(Policy) << "#"
786             << DA.getIndex() << "}";
787       } else {
788         assert(Base.get<const Expr *>() != nullptr &&
789                "Expecting non-null Expr");
790         Base.get<const Expr*>()->printPretty(Out, nullptr, Policy);
791       }
792 
793       if (!O.isZero()) {
794         Out << " + " << (O / S);
795         if (IsReference)
796           Out << ')';
797       }
798       return;
799     }
800 
801     // We have an lvalue path. Print it out nicely.
802     if (!IsReference)
803       Out << '&';
804     else if (isLValueOnePastTheEnd())
805       Out << "*(&";
806 
807     QualType ElemTy = Base.getType();
808     if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
809       Out << *VD;
810     } else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
811       TI.print(Out, Policy);
812     } else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
813       Out << "{*new " << Base.getDynamicAllocType().stream(Policy) << "#"
814           << DA.getIndex() << "}";
815     } else {
816       const Expr *E = Base.get<const Expr*>();
817       assert(E != nullptr && "Expecting non-null Expr");
818       E->printPretty(Out, nullptr, Policy);
819     }
820 
821     ArrayRef<LValuePathEntry> Path = getLValuePath();
822     const CXXRecordDecl *CastToBase = nullptr;
823     for (unsigned I = 0, N = Path.size(); I != N; ++I) {
824       if (ElemTy->isRecordType()) {
825         // The lvalue refers to a class type, so the next path entry is a base
826         // or member.
827         const Decl *BaseOrMember = Path[I].getAsBaseOrMember().getPointer();
828         if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(BaseOrMember)) {
829           CastToBase = RD;
830           // Leave ElemTy referring to the most-derived class. The actual type
831           // doesn't matter except for array types.
832         } else {
833           const ValueDecl *VD = cast<ValueDecl>(BaseOrMember);
834           Out << ".";
835           if (CastToBase)
836             Out << *CastToBase << "::";
837           Out << *VD;
838           ElemTy = VD->getType();
839         }
840       } else {
841         // The lvalue must refer to an array.
842         Out << '[' << Path[I].getAsArrayIndex() << ']';
843         ElemTy = ElemTy->castAsArrayTypeUnsafe()->getElementType();
844       }
845     }
846 
847     // Handle formatting of one-past-the-end lvalues.
848     if (isLValueOnePastTheEnd()) {
849       // FIXME: If CastToBase is non-0, we should prefix the output with
850       // "(CastToBase*)".
851       Out << " + 1";
852       if (IsReference)
853         Out << ')';
854     }
855     return;
856   }
857   case APValue::Array: {
858     const ArrayType *AT = Ty->castAsArrayTypeUnsafe();
859     unsigned N = getArrayInitializedElts();
860     if (N != 0 && TryPrintAsStringLiteral(Out, Policy, AT,
861                                           {&getArrayInitializedElt(0), N}))
862       return;
863     QualType ElemTy = AT->getElementType();
864     Out << '{';
865     unsigned I = 0;
866     switch (N) {
867     case 0:
868       for (; I != N; ++I) {
869         Out << ", ";
870         if (I == 10 && !Policy.EntireContentsOfLargeArray) {
871           Out << "...}";
872           return;
873         }
874         LLVM_FALLTHROUGH;
875       default:
876         getArrayInitializedElt(I).printPretty(Out, Policy, ElemTy, Ctx);
877       }
878     }
879     Out << '}';
880     return;
881   }
882   case APValue::Struct: {
883     Out << '{';
884     const RecordDecl *RD = Ty->castAs<RecordType>()->getDecl();
885     bool First = true;
886     if (unsigned N = getStructNumBases()) {
887       const CXXRecordDecl *CD = cast<CXXRecordDecl>(RD);
888       CXXRecordDecl::base_class_const_iterator BI = CD->bases_begin();
889       for (unsigned I = 0; I != N; ++I, ++BI) {
890         assert(BI != CD->bases_end());
891         if (!First)
892           Out << ", ";
893         getStructBase(I).printPretty(Out, Policy, BI->getType(), Ctx);
894         First = false;
895       }
896     }
897     for (const auto *FI : RD->fields()) {
898       if (!First)
899         Out << ", ";
900       if (FI->isUnnamedBitfield()) continue;
901       getStructField(FI->getFieldIndex()).
902         printPretty(Out, Policy, FI->getType(), Ctx);
903       First = false;
904     }
905     Out << '}';
906     return;
907   }
908   case APValue::Union:
909     Out << '{';
910     if (const FieldDecl *FD = getUnionField()) {
911       Out << "." << *FD << " = ";
912       getUnionValue().printPretty(Out, Policy, FD->getType(), Ctx);
913     }
914     Out << '}';
915     return;
916   case APValue::MemberPointer:
917     // FIXME: This is not enough to unambiguously identify the member in a
918     // multiple-inheritance scenario.
919     if (const ValueDecl *VD = getMemberPointerDecl()) {
920       Out << '&' << *cast<CXXRecordDecl>(VD->getDeclContext()) << "::" << *VD;
921       return;
922     }
923     Out << "0";
924     return;
925   case APValue::AddrLabelDiff:
926     Out << "&&" << getAddrLabelDiffLHS()->getLabel()->getName();
927     Out << " - ";
928     Out << "&&" << getAddrLabelDiffRHS()->getLabel()->getName();
929     return;
930   }
931   llvm_unreachable("Unknown APValue kind!");
932 }
933 
934 std::string APValue::getAsString(const ASTContext &Ctx, QualType Ty) const {
935   std::string Result;
936   llvm::raw_string_ostream Out(Result);
937   printPretty(Out, Ctx, Ty);
938   Out.flush();
939   return Result;
940 }
941 
942 bool APValue::toIntegralConstant(APSInt &Result, QualType SrcTy,
943                                  const ASTContext &Ctx) const {
944   if (isInt()) {
945     Result = getInt();
946     return true;
947   }
948 
949   if (isLValue() && isNullPointer()) {
950     Result = Ctx.MakeIntValue(Ctx.getTargetNullPointerValue(SrcTy), SrcTy);
951     return true;
952   }
953 
954   if (isLValue() && !getLValueBase()) {
955     Result = Ctx.MakeIntValue(getLValueOffset().getQuantity(), SrcTy);
956     return true;
957   }
958 
959   return false;
960 }
961 
962 const APValue::LValueBase APValue::getLValueBase() const {
963   assert(isLValue() && "Invalid accessor");
964   return ((const LV *)(const void *)&Data)->Base;
965 }
966 
967 bool APValue::isLValueOnePastTheEnd() const {
968   assert(isLValue() && "Invalid accessor");
969   return ((const LV *)(const void *)&Data)->IsOnePastTheEnd;
970 }
971 
972 CharUnits &APValue::getLValueOffset() {
973   assert(isLValue() && "Invalid accessor");
974   return ((LV *)(void *)&Data)->Offset;
975 }
976 
977 bool APValue::hasLValuePath() const {
978   assert(isLValue() && "Invalid accessor");
979   return ((const LV *)(const char *)&Data)->hasPath();
980 }
981 
982 ArrayRef<APValue::LValuePathEntry> APValue::getLValuePath() const {
983   assert(isLValue() && hasLValuePath() && "Invalid accessor");
984   const LV &LVal = *((const LV *)(const char *)&Data);
985   return llvm::makeArrayRef(LVal.getPath(), LVal.PathLength);
986 }
987 
988 unsigned APValue::getLValueCallIndex() const {
989   assert(isLValue() && "Invalid accessor");
990   return ((const LV *)(const char *)&Data)->Base.getCallIndex();
991 }
992 
993 unsigned APValue::getLValueVersion() const {
994   assert(isLValue() && "Invalid accessor");
995   return ((const LV *)(const char *)&Data)->Base.getVersion();
996 }
997 
998 bool APValue::isNullPointer() const {
999   assert(isLValue() && "Invalid usage");
1000   return ((const LV *)(const char *)&Data)->IsNullPtr;
1001 }
1002 
1003 void APValue::setLValue(LValueBase B, const CharUnits &O, NoLValuePath,
1004                         bool IsNullPtr) {
1005   assert(isLValue() && "Invalid accessor");
1006   LV &LVal = *((LV *)(char *)&Data);
1007   LVal.Base = B;
1008   LVal.IsOnePastTheEnd = false;
1009   LVal.Offset = O;
1010   LVal.resizePath((unsigned)-1);
1011   LVal.IsNullPtr = IsNullPtr;
1012 }
1013 
1014 MutableArrayRef<APValue::LValuePathEntry>
1015 APValue::setLValueUninit(LValueBase B, const CharUnits &O, unsigned Size,
1016                          bool IsOnePastTheEnd, bool IsNullPtr) {
1017   assert(isLValue() && "Invalid accessor");
1018   LV &LVal = *((LV *)(char *)&Data);
1019   LVal.Base = B;
1020   LVal.IsOnePastTheEnd = IsOnePastTheEnd;
1021   LVal.Offset = O;
1022   LVal.IsNullPtr = IsNullPtr;
1023   LVal.resizePath(Size);
1024   return {LVal.getPath(), Size};
1025 }
1026 
1027 void APValue::setLValue(LValueBase B, const CharUnits &O,
1028                         ArrayRef<LValuePathEntry> Path, bool IsOnePastTheEnd,
1029                         bool IsNullPtr) {
1030   MutableArrayRef<APValue::LValuePathEntry> InternalPath =
1031       setLValueUninit(B, O, Path.size(), IsOnePastTheEnd, IsNullPtr);
1032   if (Path.size()) {
1033     memcpy(InternalPath.data(), Path.data(),
1034            Path.size() * sizeof(LValuePathEntry));
1035   }
1036 }
1037 
1038 void APValue::setUnion(const FieldDecl *Field, const APValue &Value) {
1039   assert(isUnion() && "Invalid accessor");
1040   ((UnionData *)(char *)&Data)->Field =
1041       Field ? Field->getCanonicalDecl() : nullptr;
1042   *((UnionData *)(char *)&Data)->Value = Value;
1043 }
1044 
1045 const ValueDecl *APValue::getMemberPointerDecl() const {
1046   assert(isMemberPointer() && "Invalid accessor");
1047   const MemberPointerData &MPD =
1048       *((const MemberPointerData *)(const char *)&Data);
1049   return MPD.MemberAndIsDerivedMember.getPointer();
1050 }
1051 
1052 bool APValue::isMemberPointerToDerivedMember() const {
1053   assert(isMemberPointer() && "Invalid accessor");
1054   const MemberPointerData &MPD =
1055       *((const MemberPointerData *)(const char *)&Data);
1056   return MPD.MemberAndIsDerivedMember.getInt();
1057 }
1058 
1059 ArrayRef<const CXXRecordDecl*> APValue::getMemberPointerPath() const {
1060   assert(isMemberPointer() && "Invalid accessor");
1061   const MemberPointerData &MPD =
1062       *((const MemberPointerData *)(const char *)&Data);
1063   return llvm::makeArrayRef(MPD.getPath(), MPD.PathLength);
1064 }
1065 
1066 void APValue::MakeLValue() {
1067   assert(isAbsent() && "Bad state change");
1068   static_assert(sizeof(LV) <= DataSize, "LV too big");
1069   new ((void *)(char *)&Data) LV();
1070   Kind = LValue;
1071 }
1072 
1073 void APValue::MakeArray(unsigned InitElts, unsigned Size) {
1074   assert(isAbsent() && "Bad state change");
1075   new ((void *)(char *)&Data) Arr(InitElts, Size);
1076   Kind = Array;
1077 }
1078 
1079 MutableArrayRef<APValue::LValuePathEntry>
1080 setLValueUninit(APValue::LValueBase B, const CharUnits &O, unsigned Size,
1081                 bool OnePastTheEnd, bool IsNullPtr);
1082 
1083 MutableArrayRef<const CXXRecordDecl *>
1084 APValue::setMemberPointerUninit(const ValueDecl *Member, bool IsDerivedMember,
1085                                 unsigned Size) {
1086   assert(isAbsent() && "Bad state change");
1087   MemberPointerData *MPD = new ((void *)(char *)&Data) MemberPointerData;
1088   Kind = MemberPointer;
1089   MPD->MemberAndIsDerivedMember.setPointer(
1090       Member ? cast<ValueDecl>(Member->getCanonicalDecl()) : nullptr);
1091   MPD->MemberAndIsDerivedMember.setInt(IsDerivedMember);
1092   MPD->resizePath(Size);
1093   return {MPD->getPath(), MPD->PathLength};
1094 }
1095 
1096 void APValue::MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
1097                                 ArrayRef<const CXXRecordDecl *> Path) {
1098   MutableArrayRef<const CXXRecordDecl *> InternalPath =
1099       setMemberPointerUninit(Member, IsDerivedMember, Path.size());
1100   for (unsigned I = 0; I != Path.size(); ++I)
1101     InternalPath[I] = Path[I]->getCanonicalDecl();
1102 }
1103 
1104 LinkageInfo LinkageComputer::getLVForValue(const APValue &V,
1105                                            LVComputationKind computation) {
1106   LinkageInfo LV = LinkageInfo::external();
1107 
1108   auto MergeLV = [&](LinkageInfo MergeLV) {
1109     LV.merge(MergeLV);
1110     return LV.getLinkage() == InternalLinkage;
1111   };
1112   auto Merge = [&](const APValue &V) {
1113     return MergeLV(getLVForValue(V, computation));
1114   };
1115 
1116   switch (V.getKind()) {
1117   case APValue::None:
1118   case APValue::Indeterminate:
1119   case APValue::Int:
1120   case APValue::Float:
1121   case APValue::FixedPoint:
1122   case APValue::ComplexInt:
1123   case APValue::ComplexFloat:
1124   case APValue::Vector:
1125     break;
1126 
1127   case APValue::AddrLabelDiff:
1128     // Even for an inline function, it's not reasonable to treat a difference
1129     // between the addresses of labels as an external value.
1130     return LinkageInfo::internal();
1131 
1132   case APValue::Struct: {
1133     for (unsigned I = 0, N = V.getStructNumBases(); I != N; ++I)
1134       if (Merge(V.getStructBase(I)))
1135         break;
1136     for (unsigned I = 0, N = V.getStructNumFields(); I != N; ++I)
1137       if (Merge(V.getStructField(I)))
1138         break;
1139     break;
1140   }
1141 
1142   case APValue::Union:
1143     if (V.getUnionField())
1144       Merge(V.getUnionValue());
1145     break;
1146 
1147   case APValue::Array: {
1148     for (unsigned I = 0, N = V.getArrayInitializedElts(); I != N; ++I)
1149       if (Merge(V.getArrayInitializedElt(I)))
1150         break;
1151     if (V.hasArrayFiller())
1152       Merge(V.getArrayFiller());
1153     break;
1154   }
1155 
1156   case APValue::LValue: {
1157     if (!V.getLValueBase()) {
1158       // Null or absolute address: this is external.
1159     } else if (const auto *VD =
1160                    V.getLValueBase().dyn_cast<const ValueDecl *>()) {
1161       if (VD && MergeLV(getLVForDecl(VD, computation)))
1162         break;
1163     } else if (const auto TI = V.getLValueBase().dyn_cast<TypeInfoLValue>()) {
1164       if (MergeLV(getLVForType(*TI.getType(), computation)))
1165         break;
1166     } else if (const Expr *E = V.getLValueBase().dyn_cast<const Expr *>()) {
1167       // Almost all expression bases are internal. The exception is
1168       // lifetime-extended temporaries.
1169       // FIXME: These should be modeled as having the
1170       // LifetimeExtendedTemporaryDecl itself as the base.
1171       // FIXME: If we permit Objective-C object literals in template arguments,
1172       // they should not imply internal linkage.
1173       auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E);
1174       if (!MTE || MTE->getStorageDuration() == SD_FullExpression)
1175         return LinkageInfo::internal();
1176       if (MergeLV(getLVForDecl(MTE->getExtendingDecl(), computation)))
1177         break;
1178     } else {
1179       assert(V.getLValueBase().is<DynamicAllocLValue>() &&
1180              "unexpected LValueBase kind");
1181       return LinkageInfo::internal();
1182     }
1183     // The lvalue path doesn't matter: pointers to all subobjects always have
1184     // the same visibility as pointers to the complete object.
1185     break;
1186   }
1187 
1188   case APValue::MemberPointer:
1189     if (const NamedDecl *D = V.getMemberPointerDecl())
1190       MergeLV(getLVForDecl(D, computation));
1191     // Note that we could have a base-to-derived conversion here to a member of
1192     // a derived class with less linkage/visibility. That's covered by the
1193     // linkage and visibility of the value's type.
1194     break;
1195   }
1196 
1197   return LV;
1198 }
1199