xref: /freebsd/contrib/llvm-project/clang/lib/AST/APValue.cpp (revision e32fecd0c2c3ee37c47ee100f169e7eb0282a873) 
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().isInt() || !Inits.back().getInt().isZero())
641     return false;
642 
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     if (!Val.isInt())
659       return false;
660     int64_t Char64 = Val.getInt().getExtValue();
661     if (!isASCII(Char64))
662       return false; // Bye bye, see you in integers.
663     auto Ch = static_cast<unsigned char>(Char64);
664     // The diagnostic message is 'quoted'
665     StringRef Escaped = escapeCStyle<EscapeChar::SingleAndDouble>(Ch);
666     if (Escaped.empty()) {
667       if (!isPrintable(Ch))
668         return false;
669       Buf.emplace_back(Ch);
670     } else {
671       Buf.append(Escaped);
672     }
673   }
674 
675   Buf.append(Ellipsis);
676   Buf.push_back('"');
677 
678   if (Ty->isWideCharType())
679     Out << 'L';
680   else if (Ty->isChar8Type())
681     Out << "u8";
682   else if (Ty->isChar16Type())
683     Out << 'u';
684   else if (Ty->isChar32Type())
685     Out << 'U';
686 
687   Out << Buf;
688   return true;
689 }
690 
691 void APValue::printPretty(raw_ostream &Out, const ASTContext &Ctx,
692                           QualType Ty) const {
693   printPretty(Out, Ctx.getPrintingPolicy(), Ty, &Ctx);
694 }
695 
696 void APValue::printPretty(raw_ostream &Out, const PrintingPolicy &Policy,
697                           QualType Ty, const ASTContext *Ctx) const {
698   // There are no objects of type 'void', but values of this type can be
699   // returned from functions.
700   if (Ty->isVoidType()) {
701     Out << "void()";
702     return;
703   }
704 
705   switch (getKind()) {
706   case APValue::None:
707     Out << "<out of lifetime>";
708     return;
709   case APValue::Indeterminate:
710     Out << "<uninitialized>";
711     return;
712   case APValue::Int:
713     if (Ty->isBooleanType())
714       Out << (getInt().getBoolValue() ? "true" : "false");
715     else
716       Out << getInt();
717     return;
718   case APValue::Float:
719     Out << GetApproxValue(getFloat());
720     return;
721   case APValue::FixedPoint:
722     Out << getFixedPoint();
723     return;
724   case APValue::Vector: {
725     Out << '{';
726     QualType ElemTy = Ty->castAs<VectorType>()->getElementType();
727     getVectorElt(0).printPretty(Out, Policy, ElemTy, Ctx);
728     for (unsigned i = 1; i != getVectorLength(); ++i) {
729       Out << ", ";
730       getVectorElt(i).printPretty(Out, Policy, ElemTy, Ctx);
731     }
732     Out << '}';
733     return;
734   }
735   case APValue::ComplexInt:
736     Out << getComplexIntReal() << "+" << getComplexIntImag() << "i";
737     return;
738   case APValue::ComplexFloat:
739     Out << GetApproxValue(getComplexFloatReal()) << "+"
740         << GetApproxValue(getComplexFloatImag()) << "i";
741     return;
742   case APValue::LValue: {
743     bool IsReference = Ty->isReferenceType();
744     QualType InnerTy
745       = IsReference ? Ty.getNonReferenceType() : Ty->getPointeeType();
746     if (InnerTy.isNull())
747       InnerTy = Ty;
748 
749     LValueBase Base = getLValueBase();
750     if (!Base) {
751       if (isNullPointer()) {
752         Out << (Policy.Nullptr ? "nullptr" : "0");
753       } else if (IsReference) {
754         Out << "*(" << InnerTy.stream(Policy) << "*)"
755             << getLValueOffset().getQuantity();
756       } else {
757         Out << "(" << Ty.stream(Policy) << ")"
758             << getLValueOffset().getQuantity();
759       }
760       return;
761     }
762 
763     if (!hasLValuePath()) {
764       // No lvalue path: just print the offset.
765       CharUnits O = getLValueOffset();
766       CharUnits S = Ctx ? Ctx->getTypeSizeInCharsIfKnown(InnerTy).value_or(
767                               CharUnits::Zero())
768                         : CharUnits::Zero();
769       if (!O.isZero()) {
770         if (IsReference)
771           Out << "*(";
772         if (S.isZero() || O % S) {
773           Out << "(char*)";
774           S = CharUnits::One();
775         }
776         Out << '&';
777       } else if (!IsReference) {
778         Out << '&';
779       }
780 
781       if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
782         Out << *VD;
783       else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
784         TI.print(Out, Policy);
785       } else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
786         Out << "{*new "
787             << Base.getDynamicAllocType().stream(Policy) << "#"
788             << DA.getIndex() << "}";
789       } else {
790         assert(Base.get<const Expr *>() != nullptr &&
791                "Expecting non-null Expr");
792         Base.get<const Expr*>()->printPretty(Out, nullptr, Policy);
793       }
794 
795       if (!O.isZero()) {
796         Out << " + " << (O / S);
797         if (IsReference)
798           Out << ')';
799       }
800       return;
801     }
802 
803     // We have an lvalue path. Print it out nicely.
804     if (!IsReference)
805       Out << '&';
806     else if (isLValueOnePastTheEnd())
807       Out << "*(&";
808 
809     QualType ElemTy = Base.getType();
810     if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
811       Out << *VD;
812     } else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
813       TI.print(Out, Policy);
814     } else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
815       Out << "{*new " << Base.getDynamicAllocType().stream(Policy) << "#"
816           << DA.getIndex() << "}";
817     } else {
818       const Expr *E = Base.get<const Expr*>();
819       assert(E != nullptr && "Expecting non-null Expr");
820       E->printPretty(Out, nullptr, Policy);
821     }
822 
823     ArrayRef<LValuePathEntry> Path = getLValuePath();
824     const CXXRecordDecl *CastToBase = nullptr;
825     for (unsigned I = 0, N = Path.size(); I != N; ++I) {
826       if (ElemTy->isRecordType()) {
827         // The lvalue refers to a class type, so the next path entry is a base
828         // or member.
829         const Decl *BaseOrMember = Path[I].getAsBaseOrMember().getPointer();
830         if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(BaseOrMember)) {
831           CastToBase = RD;
832           // Leave ElemTy referring to the most-derived class. The actual type
833           // doesn't matter except for array types.
834         } else {
835           const ValueDecl *VD = cast<ValueDecl>(BaseOrMember);
836           Out << ".";
837           if (CastToBase)
838             Out << *CastToBase << "::";
839           Out << *VD;
840           ElemTy = VD->getType();
841         }
842       } else {
843         // The lvalue must refer to an array.
844         Out << '[' << Path[I].getAsArrayIndex() << ']';
845         ElemTy = ElemTy->castAsArrayTypeUnsafe()->getElementType();
846       }
847     }
848 
849     // Handle formatting of one-past-the-end lvalues.
850     if (isLValueOnePastTheEnd()) {
851       // FIXME: If CastToBase is non-0, we should prefix the output with
852       // "(CastToBase*)".
853       Out << " + 1";
854       if (IsReference)
855         Out << ')';
856     }
857     return;
858   }
859   case APValue::Array: {
860     const ArrayType *AT = Ty->castAsArrayTypeUnsafe();
861     unsigned N = getArrayInitializedElts();
862     if (N != 0 && TryPrintAsStringLiteral(Out, Policy, AT,
863                                           {&getArrayInitializedElt(0), N}))
864       return;
865     QualType ElemTy = AT->getElementType();
866     Out << '{';
867     unsigned I = 0;
868     switch (N) {
869     case 0:
870       for (; I != N; ++I) {
871         Out << ", ";
872         if (I == 10 && !Policy.EntireContentsOfLargeArray) {
873           Out << "...}";
874           return;
875         }
876         LLVM_FALLTHROUGH;
877       default:
878         getArrayInitializedElt(I).printPretty(Out, Policy, ElemTy, Ctx);
879       }
880     }
881     Out << '}';
882     return;
883   }
884   case APValue::Struct: {
885     Out << '{';
886     const RecordDecl *RD = Ty->castAs<RecordType>()->getDecl();
887     bool First = true;
888     if (unsigned N = getStructNumBases()) {
889       const CXXRecordDecl *CD = cast<CXXRecordDecl>(RD);
890       CXXRecordDecl::base_class_const_iterator BI = CD->bases_begin();
891       for (unsigned I = 0; I != N; ++I, ++BI) {
892         assert(BI != CD->bases_end());
893         if (!First)
894           Out << ", ";
895         getStructBase(I).printPretty(Out, Policy, BI->getType(), Ctx);
896         First = false;
897       }
898     }
899     for (const auto *FI : RD->fields()) {
900       if (!First)
901         Out << ", ";
902       if (FI->isUnnamedBitfield()) continue;
903       getStructField(FI->getFieldIndex()).
904         printPretty(Out, Policy, FI->getType(), Ctx);
905       First = false;
906     }
907     Out << '}';
908     return;
909   }
910   case APValue::Union:
911     Out << '{';
912     if (const FieldDecl *FD = getUnionField()) {
913       Out << "." << *FD << " = ";
914       getUnionValue().printPretty(Out, Policy, FD->getType(), Ctx);
915     }
916     Out << '}';
917     return;
918   case APValue::MemberPointer:
919     // FIXME: This is not enough to unambiguously identify the member in a
920     // multiple-inheritance scenario.
921     if (const ValueDecl *VD = getMemberPointerDecl()) {
922       Out << '&' << *cast<CXXRecordDecl>(VD->getDeclContext()) << "::" << *VD;
923       return;
924     }
925     Out << "0";
926     return;
927   case APValue::AddrLabelDiff:
928     Out << "&&" << getAddrLabelDiffLHS()->getLabel()->getName();
929     Out << " - ";
930     Out << "&&" << getAddrLabelDiffRHS()->getLabel()->getName();
931     return;
932   }
933   llvm_unreachable("Unknown APValue kind!");
934 }
935 
936 std::string APValue::getAsString(const ASTContext &Ctx, QualType Ty) const {
937   std::string Result;
938   llvm::raw_string_ostream Out(Result);
939   printPretty(Out, Ctx, Ty);
940   Out.flush();
941   return Result;
942 }
943 
944 bool APValue::toIntegralConstant(APSInt &Result, QualType SrcTy,
945                                  const ASTContext &Ctx) const {
946   if (isInt()) {
947     Result = getInt();
948     return true;
949   }
950 
951   if (isLValue() && isNullPointer()) {
952     Result = Ctx.MakeIntValue(Ctx.getTargetNullPointerValue(SrcTy), SrcTy);
953     return true;
954   }
955 
956   if (isLValue() && !getLValueBase()) {
957     Result = Ctx.MakeIntValue(getLValueOffset().getQuantity(), SrcTy);
958     return true;
959   }
960 
961   return false;
962 }
963 
964 const APValue::LValueBase APValue::getLValueBase() const {
965   assert(isLValue() && "Invalid accessor");
966   return ((const LV *)(const void *)&Data)->Base;
967 }
968 
969 bool APValue::isLValueOnePastTheEnd() const {
970   assert(isLValue() && "Invalid accessor");
971   return ((const LV *)(const void *)&Data)->IsOnePastTheEnd;
972 }
973 
974 CharUnits &APValue::getLValueOffset() {
975   assert(isLValue() && "Invalid accessor");
976   return ((LV *)(void *)&Data)->Offset;
977 }
978 
979 bool APValue::hasLValuePath() const {
980   assert(isLValue() && "Invalid accessor");
981   return ((const LV *)(const char *)&Data)->hasPath();
982 }
983 
984 ArrayRef<APValue::LValuePathEntry> APValue::getLValuePath() const {
985   assert(isLValue() && hasLValuePath() && "Invalid accessor");
986   const LV &LVal = *((const LV *)(const char *)&Data);
987   return llvm::makeArrayRef(LVal.getPath(), LVal.PathLength);
988 }
989 
990 unsigned APValue::getLValueCallIndex() const {
991   assert(isLValue() && "Invalid accessor");
992   return ((const LV *)(const char *)&Data)->Base.getCallIndex();
993 }
994 
995 unsigned APValue::getLValueVersion() const {
996   assert(isLValue() && "Invalid accessor");
997   return ((const LV *)(const char *)&Data)->Base.getVersion();
998 }
999 
1000 bool APValue::isNullPointer() const {
1001   assert(isLValue() && "Invalid usage");
1002   return ((const LV *)(const char *)&Data)->IsNullPtr;
1003 }
1004 
1005 void APValue::setLValue(LValueBase B, const CharUnits &O, NoLValuePath,
1006                         bool IsNullPtr) {
1007   assert(isLValue() && "Invalid accessor");
1008   LV &LVal = *((LV *)(char *)&Data);
1009   LVal.Base = B;
1010   LVal.IsOnePastTheEnd = false;
1011   LVal.Offset = O;
1012   LVal.resizePath((unsigned)-1);
1013   LVal.IsNullPtr = IsNullPtr;
1014 }
1015 
1016 MutableArrayRef<APValue::LValuePathEntry>
1017 APValue::setLValueUninit(LValueBase B, const CharUnits &O, unsigned Size,
1018                          bool IsOnePastTheEnd, bool IsNullPtr) {
1019   assert(isLValue() && "Invalid accessor");
1020   LV &LVal = *((LV *)(char *)&Data);
1021   LVal.Base = B;
1022   LVal.IsOnePastTheEnd = IsOnePastTheEnd;
1023   LVal.Offset = O;
1024   LVal.IsNullPtr = IsNullPtr;
1025   LVal.resizePath(Size);
1026   return {LVal.getPath(), Size};
1027 }
1028 
1029 void APValue::setLValue(LValueBase B, const CharUnits &O,
1030                         ArrayRef<LValuePathEntry> Path, bool IsOnePastTheEnd,
1031                         bool IsNullPtr) {
1032   MutableArrayRef<APValue::LValuePathEntry> InternalPath =
1033       setLValueUninit(B, O, Path.size(), IsOnePastTheEnd, IsNullPtr);
1034   if (Path.size()) {
1035     memcpy(InternalPath.data(), Path.data(),
1036            Path.size() * sizeof(LValuePathEntry));
1037   }
1038 }
1039 
1040 void APValue::setUnion(const FieldDecl *Field, const APValue &Value) {
1041   assert(isUnion() && "Invalid accessor");
1042   ((UnionData *)(char *)&Data)->Field =
1043       Field ? Field->getCanonicalDecl() : nullptr;
1044   *((UnionData *)(char *)&Data)->Value = Value;
1045 }
1046 
1047 const ValueDecl *APValue::getMemberPointerDecl() const {
1048   assert(isMemberPointer() && "Invalid accessor");
1049   const MemberPointerData &MPD =
1050       *((const MemberPointerData *)(const char *)&Data);
1051   return MPD.MemberAndIsDerivedMember.getPointer();
1052 }
1053 
1054 bool APValue::isMemberPointerToDerivedMember() const {
1055   assert(isMemberPointer() && "Invalid accessor");
1056   const MemberPointerData &MPD =
1057       *((const MemberPointerData *)(const char *)&Data);
1058   return MPD.MemberAndIsDerivedMember.getInt();
1059 }
1060 
1061 ArrayRef<const CXXRecordDecl*> APValue::getMemberPointerPath() const {
1062   assert(isMemberPointer() && "Invalid accessor");
1063   const MemberPointerData &MPD =
1064       *((const MemberPointerData *)(const char *)&Data);
1065   return llvm::makeArrayRef(MPD.getPath(), MPD.PathLength);
1066 }
1067 
1068 void APValue::MakeLValue() {
1069   assert(isAbsent() && "Bad state change");
1070   static_assert(sizeof(LV) <= DataSize, "LV too big");
1071   new ((void *)(char *)&Data) LV();
1072   Kind = LValue;
1073 }
1074 
1075 void APValue::MakeArray(unsigned InitElts, unsigned Size) {
1076   assert(isAbsent() && "Bad state change");
1077   new ((void *)(char *)&Data) Arr(InitElts, Size);
1078   Kind = Array;
1079 }
1080 
1081 MutableArrayRef<APValue::LValuePathEntry>
1082 setLValueUninit(APValue::LValueBase B, const CharUnits &O, unsigned Size,
1083                 bool OnePastTheEnd, bool IsNullPtr);
1084 
1085 MutableArrayRef<const CXXRecordDecl *>
1086 APValue::setMemberPointerUninit(const ValueDecl *Member, bool IsDerivedMember,
1087                                 unsigned Size) {
1088   assert(isAbsent() && "Bad state change");
1089   MemberPointerData *MPD = new ((void *)(char *)&Data) MemberPointerData;
1090   Kind = MemberPointer;
1091   MPD->MemberAndIsDerivedMember.setPointer(
1092       Member ? cast<ValueDecl>(Member->getCanonicalDecl()) : nullptr);
1093   MPD->MemberAndIsDerivedMember.setInt(IsDerivedMember);
1094   MPD->resizePath(Size);
1095   return {MPD->getPath(), MPD->PathLength};
1096 }
1097 
1098 void APValue::MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
1099                                 ArrayRef<const CXXRecordDecl *> Path) {
1100   MutableArrayRef<const CXXRecordDecl *> InternalPath =
1101       setMemberPointerUninit(Member, IsDerivedMember, Path.size());
1102   for (unsigned I = 0; I != Path.size(); ++I)
1103     InternalPath[I] = Path[I]->getCanonicalDecl();
1104 }
1105 
1106 LinkageInfo LinkageComputer::getLVForValue(const APValue &V,
1107                                            LVComputationKind computation) {
1108   LinkageInfo LV = LinkageInfo::external();
1109 
1110   auto MergeLV = [&](LinkageInfo MergeLV) {
1111     LV.merge(MergeLV);
1112     return LV.getLinkage() == InternalLinkage;
1113   };
1114   auto Merge = [&](const APValue &V) {
1115     return MergeLV(getLVForValue(V, computation));
1116   };
1117 
1118   switch (V.getKind()) {
1119   case APValue::None:
1120   case APValue::Indeterminate:
1121   case APValue::Int:
1122   case APValue::Float:
1123   case APValue::FixedPoint:
1124   case APValue::ComplexInt:
1125   case APValue::ComplexFloat:
1126   case APValue::Vector:
1127     break;
1128 
1129   case APValue::AddrLabelDiff:
1130     // Even for an inline function, it's not reasonable to treat a difference
1131     // between the addresses of labels as an external value.
1132     return LinkageInfo::internal();
1133 
1134   case APValue::Struct: {
1135     for (unsigned I = 0, N = V.getStructNumBases(); I != N; ++I)
1136       if (Merge(V.getStructBase(I)))
1137         break;
1138     for (unsigned I = 0, N = V.getStructNumFields(); I != N; ++I)
1139       if (Merge(V.getStructField(I)))
1140         break;
1141     break;
1142   }
1143 
1144   case APValue::Union:
1145     if (V.getUnionField())
1146       Merge(V.getUnionValue());
1147     break;
1148 
1149   case APValue::Array: {
1150     for (unsigned I = 0, N = V.getArrayInitializedElts(); I != N; ++I)
1151       if (Merge(V.getArrayInitializedElt(I)))
1152         break;
1153     if (V.hasArrayFiller())
1154       Merge(V.getArrayFiller());
1155     break;
1156   }
1157 
1158   case APValue::LValue: {
1159     if (!V.getLValueBase()) {
1160       // Null or absolute address: this is external.
1161     } else if (const auto *VD =
1162                    V.getLValueBase().dyn_cast<const ValueDecl *>()) {
1163       if (VD && MergeLV(getLVForDecl(VD, computation)))
1164         break;
1165     } else if (const auto TI = V.getLValueBase().dyn_cast<TypeInfoLValue>()) {
1166       if (MergeLV(getLVForType(*TI.getType(), computation)))
1167         break;
1168     } else if (const Expr *E = V.getLValueBase().dyn_cast<const Expr *>()) {
1169       // Almost all expression bases are internal. The exception is
1170       // lifetime-extended temporaries.
1171       // FIXME: These should be modeled as having the
1172       // LifetimeExtendedTemporaryDecl itself as the base.
1173       // FIXME: If we permit Objective-C object literals in template arguments,
1174       // they should not imply internal linkage.
1175       auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E);
1176       if (!MTE || MTE->getStorageDuration() == SD_FullExpression)
1177         return LinkageInfo::internal();
1178       if (MergeLV(getLVForDecl(MTE->getExtendingDecl(), computation)))
1179         break;
1180     } else {
1181       assert(V.getLValueBase().is<DynamicAllocLValue>() &&
1182              "unexpected LValueBase kind");
1183       return LinkageInfo::internal();
1184     }
1185     // The lvalue path doesn't matter: pointers to all subobjects always have
1186     // the same visibility as pointers to the complete object.
1187     break;
1188   }
1189 
1190   case APValue::MemberPointer:
1191     if (const NamedDecl *D = V.getMemberPointerDecl())
1192       MergeLV(getLVForDecl(D, computation));
1193     // Note that we could have a base-to-derived conversion here to a member of
1194     // a derived class with less linkage/visibility. That's covered by the
1195     // linkage and visibility of the value's type.
1196     break;
1197   }
1198 
1199   return LV;
1200 }
1201