xref: /freebsd/contrib/llvm-project/clang/lib/AST/APValue.cpp (revision e64bea71c21eb42e97aa615188ba91f6cce0d36d) 
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           llvm::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     : Ty((const void *)ElemTy.getTypePtrOrNull()), Path(Path) {}
160 
161 QualType APValue::LValuePathSerializationHelper::getType() {
162   return QualType::getFromOpaquePtr(Ty);
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)
312     : Kind(None), AllowConstexprUnknown(RHS.AllowConstexprUnknown) {
313   switch (RHS.getKind()) {
314   case None:
315   case Indeterminate:
316     Kind = RHS.getKind();
317     break;
318   case Int:
319     MakeInt();
320     setInt(RHS.getInt());
321     break;
322   case Float:
323     MakeFloat();
324     setFloat(RHS.getFloat());
325     break;
326   case FixedPoint: {
327     APFixedPoint FXCopy = RHS.getFixedPoint();
328     MakeFixedPoint(std::move(FXCopy));
329     break;
330   }
331   case Vector:
332     MakeVector();
333     setVector(((const Vec *)(const char *)&RHS.Data)->Elts,
334               RHS.getVectorLength());
335     break;
336   case ComplexInt:
337     MakeComplexInt();
338     setComplexInt(RHS.getComplexIntReal(), RHS.getComplexIntImag());
339     break;
340   case ComplexFloat:
341     MakeComplexFloat();
342     setComplexFloat(RHS.getComplexFloatReal(), RHS.getComplexFloatImag());
343     break;
344   case LValue:
345     MakeLValue();
346     if (RHS.hasLValuePath())
347       setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), RHS.getLValuePath(),
348                 RHS.isLValueOnePastTheEnd(), RHS.isNullPointer());
349     else
350       setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), NoLValuePath(),
351                 RHS.isNullPointer());
352     break;
353   case Array:
354     MakeArray(RHS.getArrayInitializedElts(), RHS.getArraySize());
355     for (unsigned I = 0, N = RHS.getArrayInitializedElts(); I != N; ++I)
356       getArrayInitializedElt(I) = RHS.getArrayInitializedElt(I);
357     if (RHS.hasArrayFiller())
358       getArrayFiller() = RHS.getArrayFiller();
359     break;
360   case Struct:
361     MakeStruct(RHS.getStructNumBases(), RHS.getStructNumFields());
362     for (unsigned I = 0, N = RHS.getStructNumBases(); I != N; ++I)
363       getStructBase(I) = RHS.getStructBase(I);
364     for (unsigned I = 0, N = RHS.getStructNumFields(); I != N; ++I)
365       getStructField(I) = RHS.getStructField(I);
366     break;
367   case Union:
368     MakeUnion();
369     setUnion(RHS.getUnionField(), RHS.getUnionValue());
370     break;
371   case MemberPointer:
372     MakeMemberPointer(RHS.getMemberPointerDecl(),
373                       RHS.isMemberPointerToDerivedMember(),
374                       RHS.getMemberPointerPath());
375     break;
376   case AddrLabelDiff:
377     MakeAddrLabelDiff();
378     setAddrLabelDiff(RHS.getAddrLabelDiffLHS(), RHS.getAddrLabelDiffRHS());
379     break;
380   }
381 }
382 
383 APValue::APValue(APValue &&RHS)
384     : Kind(RHS.Kind), AllowConstexprUnknown(RHS.AllowConstexprUnknown),
385       Data(RHS.Data) {
386   RHS.Kind = None;
387 }
388 
389 APValue &APValue::operator=(const APValue &RHS) {
390   if (this != &RHS)
391     *this = APValue(RHS);
392 
393   return *this;
394 }
395 
396 APValue &APValue::operator=(APValue &&RHS) {
397   if (this != &RHS) {
398     if (Kind != None && Kind != Indeterminate)
399       DestroyDataAndMakeUninit();
400     Kind = RHS.Kind;
401     Data = RHS.Data;
402     AllowConstexprUnknown = RHS.AllowConstexprUnknown;
403     RHS.Kind = None;
404   }
405   return *this;
406 }
407 
408 void APValue::DestroyDataAndMakeUninit() {
409   if (Kind == Int)
410     ((APSInt *)(char *)&Data)->~APSInt();
411   else if (Kind == Float)
412     ((APFloat *)(char *)&Data)->~APFloat();
413   else if (Kind == FixedPoint)
414     ((APFixedPoint *)(char *)&Data)->~APFixedPoint();
415   else if (Kind == Vector)
416     ((Vec *)(char *)&Data)->~Vec();
417   else if (Kind == ComplexInt)
418     ((ComplexAPSInt *)(char *)&Data)->~ComplexAPSInt();
419   else if (Kind == ComplexFloat)
420     ((ComplexAPFloat *)(char *)&Data)->~ComplexAPFloat();
421   else if (Kind == LValue)
422     ((LV *)(char *)&Data)->~LV();
423   else if (Kind == Array)
424     ((Arr *)(char *)&Data)->~Arr();
425   else if (Kind == Struct)
426     ((StructData *)(char *)&Data)->~StructData();
427   else if (Kind == Union)
428     ((UnionData *)(char *)&Data)->~UnionData();
429   else if (Kind == MemberPointer)
430     ((MemberPointerData *)(char *)&Data)->~MemberPointerData();
431   else if (Kind == AddrLabelDiff)
432     ((AddrLabelDiffData *)(char *)&Data)->~AddrLabelDiffData();
433   Kind = None;
434   AllowConstexprUnknown = false;
435 }
436 
437 bool APValue::needsCleanup() const {
438   switch (getKind()) {
439   case None:
440   case Indeterminate:
441   case AddrLabelDiff:
442     return false;
443   case Struct:
444   case Union:
445   case Array:
446   case Vector:
447     return true;
448   case Int:
449     return getInt().needsCleanup();
450   case Float:
451     return getFloat().needsCleanup();
452   case FixedPoint:
453     return getFixedPoint().getValue().needsCleanup();
454   case ComplexFloat:
455     assert(getComplexFloatImag().needsCleanup() ==
456                getComplexFloatReal().needsCleanup() &&
457            "In _Complex float types, real and imaginary values always have the "
458            "same size.");
459     return getComplexFloatReal().needsCleanup();
460   case ComplexInt:
461     assert(getComplexIntImag().needsCleanup() ==
462                getComplexIntReal().needsCleanup() &&
463            "In _Complex int types, real and imaginary values must have the "
464            "same size.");
465     return getComplexIntReal().needsCleanup();
466   case LValue:
467     return reinterpret_cast<const LV *>(&Data)->hasPathPtr();
468   case MemberPointer:
469     return reinterpret_cast<const MemberPointerData *>(&Data)->hasPathPtr();
470   }
471   llvm_unreachable("Unknown APValue kind!");
472 }
473 
474 void APValue::swap(APValue &RHS) {
475   std::swap(Kind, RHS.Kind);
476   std::swap(Data, RHS.Data);
477   // We can't use std::swap w/ bit-fields
478   bool tmp = AllowConstexprUnknown;
479   AllowConstexprUnknown = RHS.AllowConstexprUnknown;
480   RHS.AllowConstexprUnknown = tmp;
481 }
482 
483 /// Profile the value of an APInt, excluding its bit-width.
484 static void profileIntValue(llvm::FoldingSetNodeID &ID, const llvm::APInt &V) {
485   for (unsigned I = 0, N = V.getBitWidth(); I < N; I += 32)
486     ID.AddInteger((uint32_t)V.extractBitsAsZExtValue(std::min(32u, N - I), I));
487 }
488 
489 void APValue::Profile(llvm::FoldingSetNodeID &ID) const {
490   // Note that our profiling assumes that only APValues of the same type are
491   // ever compared. As a result, we don't consider collisions that could only
492   // happen if the types are different. (For example, structs with different
493   // numbers of members could profile the same.)
494 
495   ID.AddInteger(Kind);
496 
497   switch (Kind) {
498   case None:
499   case Indeterminate:
500     return;
501 
502   case AddrLabelDiff:
503     ID.AddPointer(getAddrLabelDiffLHS()->getLabel()->getCanonicalDecl());
504     ID.AddPointer(getAddrLabelDiffRHS()->getLabel()->getCanonicalDecl());
505     return;
506 
507   case Struct:
508     for (unsigned I = 0, N = getStructNumBases(); I != N; ++I)
509       getStructBase(I).Profile(ID);
510     for (unsigned I = 0, N = getStructNumFields(); I != N; ++I)
511       getStructField(I).Profile(ID);
512     return;
513 
514   case Union:
515     if (!getUnionField()) {
516       ID.AddInteger(0);
517       return;
518     }
519     ID.AddInteger(getUnionField()->getFieldIndex() + 1);
520     getUnionValue().Profile(ID);
521     return;
522 
523   case Array: {
524     if (getArraySize() == 0)
525       return;
526 
527     // The profile should not depend on whether the array is expanded or
528     // not, but we don't want to profile the array filler many times for
529     // a large array. So treat all equal trailing elements as the filler.
530     // Elements are profiled in reverse order to support this, and the
531     // first profiled element is followed by a count. For example:
532     //
533     //   ['a', 'c', 'x', 'x', 'x'] is profiled as
534     //   [5, 'x', 3, 'c', 'a']
535     llvm::FoldingSetNodeID FillerID;
536     (hasArrayFiller() ? getArrayFiller()
537                       : getArrayInitializedElt(getArrayInitializedElts() - 1))
538         .Profile(FillerID);
539     ID.AddNodeID(FillerID);
540     unsigned NumFillers = getArraySize() - getArrayInitializedElts();
541     unsigned N = getArrayInitializedElts();
542 
543     // Count the number of elements equal to the last one. This loop ends
544     // by adding an integer indicating the number of such elements, with
545     // N set to the number of elements left to profile.
546     while (true) {
547       if (N == 0) {
548         // All elements are fillers.
549         assert(NumFillers == getArraySize());
550         ID.AddInteger(NumFillers);
551         break;
552       }
553 
554       // No need to check if the last element is equal to the last
555       // element.
556       if (N != getArraySize()) {
557         llvm::FoldingSetNodeID ElemID;
558         getArrayInitializedElt(N - 1).Profile(ElemID);
559         if (ElemID != FillerID) {
560           ID.AddInteger(NumFillers);
561           ID.AddNodeID(ElemID);
562           --N;
563           break;
564         }
565       }
566 
567       // This is a filler.
568       ++NumFillers;
569       --N;
570     }
571 
572     // Emit the remaining elements.
573     for (; N != 0; --N)
574       getArrayInitializedElt(N - 1).Profile(ID);
575     return;
576   }
577 
578   case Vector:
579     for (unsigned I = 0, N = getVectorLength(); I != N; ++I)
580       getVectorElt(I).Profile(ID);
581     return;
582 
583   case Int:
584     profileIntValue(ID, getInt());
585     return;
586 
587   case Float:
588     profileIntValue(ID, getFloat().bitcastToAPInt());
589     return;
590 
591   case FixedPoint:
592     profileIntValue(ID, getFixedPoint().getValue());
593     return;
594 
595   case ComplexFloat:
596     profileIntValue(ID, getComplexFloatReal().bitcastToAPInt());
597     profileIntValue(ID, getComplexFloatImag().bitcastToAPInt());
598     return;
599 
600   case ComplexInt:
601     profileIntValue(ID, getComplexIntReal());
602     profileIntValue(ID, getComplexIntImag());
603     return;
604 
605   case LValue:
606     getLValueBase().Profile(ID);
607     ID.AddInteger(getLValueOffset().getQuantity());
608     ID.AddInteger((isNullPointer() ? 1 : 0) |
609                   (isLValueOnePastTheEnd() ? 2 : 0) |
610                   (hasLValuePath() ? 4 : 0));
611     if (hasLValuePath()) {
612       ID.AddInteger(getLValuePath().size());
613       // For uniqueness, we only need to profile the entries corresponding
614       // to union members, but we don't have the type here so we don't know
615       // how to interpret the entries.
616       for (LValuePathEntry E : getLValuePath())
617         E.Profile(ID);
618     }
619     return;
620 
621   case MemberPointer:
622     ID.AddPointer(getMemberPointerDecl());
623     ID.AddInteger(isMemberPointerToDerivedMember());
624     for (const CXXRecordDecl *D : getMemberPointerPath())
625       ID.AddPointer(D);
626     return;
627   }
628 
629   llvm_unreachable("Unknown APValue kind!");
630 }
631 
632 static double GetApproxValue(const llvm::APFloat &F) {
633   llvm::APFloat V = F;
634   bool ignored;
635   V.convert(llvm::APFloat::IEEEdouble(), llvm::APFloat::rmNearestTiesToEven,
636             &ignored);
637   return V.convertToDouble();
638 }
639 
640 static bool TryPrintAsStringLiteral(raw_ostream &Out,
641                                     const PrintingPolicy &Policy,
642                                     const ArrayType *ATy,
643                                     ArrayRef<APValue> Inits) {
644   if (Inits.empty())
645     return false;
646 
647   QualType Ty = ATy->getElementType();
648   if (!Ty->isAnyCharacterType())
649     return false;
650 
651   // Nothing we can do about a sequence that is not null-terminated
652   if (!Inits.back().isInt() || !Inits.back().getInt().isZero())
653     return false;
654 
655   Inits = Inits.drop_back();
656 
657   llvm::SmallString<40> Buf;
658   Buf.push_back('"');
659 
660   // Better than printing a two-digit sequence of 10 integers.
661   constexpr size_t MaxN = 36;
662   StringRef Ellipsis;
663   if (Inits.size() > MaxN && !Policy.EntireContentsOfLargeArray) {
664     Ellipsis = "[...]";
665     Inits =
666         Inits.take_front(std::min(MaxN - Ellipsis.size() / 2, Inits.size()));
667   }
668 
669   for (auto &Val : Inits) {
670     if (!Val.isInt())
671       return false;
672     int64_t Char64 = Val.getInt().getExtValue();
673     if (!isASCII(Char64))
674       return false; // Bye bye, see you in integers.
675     auto Ch = static_cast<unsigned char>(Char64);
676     // The diagnostic message is 'quoted'
677     StringRef Escaped = escapeCStyle<EscapeChar::SingleAndDouble>(Ch);
678     if (Escaped.empty()) {
679       if (!isPrintable(Ch))
680         return false;
681       Buf.emplace_back(Ch);
682     } else {
683       Buf.append(Escaped);
684     }
685   }
686 
687   Buf.append(Ellipsis);
688   Buf.push_back('"');
689 
690   if (Ty->isWideCharType())
691     Out << 'L';
692   else if (Ty->isChar8Type())
693     Out << "u8";
694   else if (Ty->isChar16Type())
695     Out << 'u';
696   else if (Ty->isChar32Type())
697     Out << 'U';
698 
699   Out << Buf;
700   return true;
701 }
702 
703 void APValue::printPretty(raw_ostream &Out, const ASTContext &Ctx,
704                           QualType Ty) const {
705   printPretty(Out, Ctx.getPrintingPolicy(), Ty, &Ctx);
706 }
707 
708 void APValue::printPretty(raw_ostream &Out, const PrintingPolicy &Policy,
709                           QualType Ty, const ASTContext *Ctx) const {
710   // There are no objects of type 'void', but values of this type can be
711   // returned from functions.
712   if (Ty->isVoidType()) {
713     Out << "void()";
714     return;
715   }
716 
717   if (const auto *AT = Ty->getAs<AtomicType>())
718     Ty = AT->getValueType();
719 
720   switch (getKind()) {
721   case APValue::None:
722     Out << "<out of lifetime>";
723     return;
724   case APValue::Indeterminate:
725     Out << "<uninitialized>";
726     return;
727   case APValue::Int:
728     if (Ty->isBooleanType())
729       Out << (getInt().getBoolValue() ? "true" : "false");
730     else
731       Out << getInt();
732     return;
733   case APValue::Float:
734     Out << GetApproxValue(getFloat());
735     return;
736   case APValue::FixedPoint:
737     Out << getFixedPoint();
738     return;
739   case APValue::Vector: {
740     Out << '{';
741     QualType ElemTy = Ty->castAs<VectorType>()->getElementType();
742     getVectorElt(0).printPretty(Out, Policy, ElemTy, Ctx);
743     for (unsigned i = 1; i != getVectorLength(); ++i) {
744       Out << ", ";
745       getVectorElt(i).printPretty(Out, Policy, ElemTy, Ctx);
746     }
747     Out << '}';
748     return;
749   }
750   case APValue::ComplexInt:
751     Out << getComplexIntReal() << "+" << getComplexIntImag() << "i";
752     return;
753   case APValue::ComplexFloat:
754     Out << GetApproxValue(getComplexFloatReal()) << "+"
755         << GetApproxValue(getComplexFloatImag()) << "i";
756     return;
757   case APValue::LValue: {
758     bool IsReference = Ty->isReferenceType();
759     QualType InnerTy
760       = IsReference ? Ty.getNonReferenceType() : Ty->getPointeeType();
761     if (InnerTy.isNull())
762       InnerTy = Ty;
763 
764     LValueBase Base = getLValueBase();
765     if (!Base) {
766       if (isNullPointer()) {
767         Out << (Policy.Nullptr ? "nullptr" : "0");
768       } else if (IsReference) {
769         Out << "*(" << InnerTy.stream(Policy) << "*)"
770             << getLValueOffset().getQuantity();
771       } else {
772         Out << "(" << Ty.stream(Policy) << ")"
773             << getLValueOffset().getQuantity();
774       }
775       return;
776     }
777 
778     if (!hasLValuePath()) {
779       // No lvalue path: just print the offset.
780       CharUnits O = getLValueOffset();
781       CharUnits S = Ctx ? Ctx->getTypeSizeInCharsIfKnown(InnerTy).value_or(
782                               CharUnits::Zero())
783                         : CharUnits::Zero();
784       if (!O.isZero()) {
785         if (IsReference)
786           Out << "*(";
787         if (S.isZero() || O % S) {
788           Out << "(char*)";
789           S = CharUnits::One();
790         }
791         Out << '&';
792       } else if (!IsReference) {
793         Out << '&';
794       }
795 
796       if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
797         Out << *VD;
798       else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
799         TI.print(Out, Policy);
800       } else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
801         Out << "{*new "
802             << Base.getDynamicAllocType().stream(Policy) << "#"
803             << DA.getIndex() << "}";
804       } else {
805         assert(Base.get<const Expr *>() != nullptr &&
806                "Expecting non-null Expr");
807         Base.get<const Expr*>()->printPretty(Out, nullptr, Policy);
808       }
809 
810       if (!O.isZero()) {
811         Out << " + " << (O / S);
812         if (IsReference)
813           Out << ')';
814       }
815       return;
816     }
817 
818     // We have an lvalue path. Print it out nicely.
819     if (!IsReference)
820       Out << '&';
821     else if (isLValueOnePastTheEnd())
822       Out << "*(&";
823 
824     QualType ElemTy = Base.getType().getNonReferenceType();
825     if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
826       Out << *VD;
827     } else if (TypeInfoLValue TI = Base.dyn_cast<TypeInfoLValue>()) {
828       TI.print(Out, Policy);
829     } else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
830       Out << "{*new " << Base.getDynamicAllocType().stream(Policy) << "#"
831           << DA.getIndex() << "}";
832     } else {
833       const Expr *E = Base.get<const Expr*>();
834       assert(E != nullptr && "Expecting non-null Expr");
835       E->printPretty(Out, nullptr, Policy);
836     }
837 
838     ArrayRef<LValuePathEntry> Path = getLValuePath();
839     const CXXRecordDecl *CastToBase = nullptr;
840     for (unsigned I = 0, N = Path.size(); I != N; ++I) {
841       if (ElemTy->isRecordType()) {
842         // The lvalue refers to a class type, so the next path entry is a base
843         // or member.
844         const Decl *BaseOrMember = Path[I].getAsBaseOrMember().getPointer();
845         if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(BaseOrMember)) {
846           CastToBase = RD;
847           // Leave ElemTy referring to the most-derived class. The actual type
848           // doesn't matter except for array types.
849         } else {
850           const ValueDecl *VD = cast<ValueDecl>(BaseOrMember);
851           Out << ".";
852           if (CastToBase)
853             Out << *CastToBase << "::";
854           Out << *VD;
855           ElemTy = VD->getType();
856         }
857       } else if (ElemTy->isAnyComplexType()) {
858         // The lvalue refers to a complex type
859         Out << (Path[I].getAsArrayIndex() == 0 ? ".real" : ".imag");
860         ElemTy = ElemTy->castAs<ComplexType>()->getElementType();
861       } else {
862         // The lvalue must refer to an array.
863         Out << '[' << Path[I].getAsArrayIndex() << ']';
864         ElemTy = ElemTy->castAsArrayTypeUnsafe()->getElementType();
865       }
866     }
867 
868     // Handle formatting of one-past-the-end lvalues.
869     if (isLValueOnePastTheEnd()) {
870       // FIXME: If CastToBase is non-0, we should prefix the output with
871       // "(CastToBase*)".
872       Out << " + 1";
873       if (IsReference)
874         Out << ')';
875     }
876     return;
877   }
878   case APValue::Array: {
879     const ArrayType *AT = Ty->castAsArrayTypeUnsafe();
880     unsigned N = getArrayInitializedElts();
881     if (N != 0 && TryPrintAsStringLiteral(Out, Policy, AT,
882                                           {&getArrayInitializedElt(0), N}))
883       return;
884     QualType ElemTy = AT->getElementType();
885     Out << '{';
886     unsigned I = 0;
887     switch (N) {
888     case 0:
889       for (; I != N; ++I) {
890         Out << ", ";
891         if (I == 10 && !Policy.EntireContentsOfLargeArray) {
892           Out << "...}";
893           return;
894         }
895         [[fallthrough]];
896       default:
897         getArrayInitializedElt(I).printPretty(Out, Policy, ElemTy, Ctx);
898       }
899     }
900     Out << '}';
901     return;
902   }
903   case APValue::Struct: {
904     Out << '{';
905     const RecordDecl *RD = Ty->castAs<RecordType>()->getDecl();
906     bool First = true;
907     if (unsigned N = getStructNumBases()) {
908       const CXXRecordDecl *CD = cast<CXXRecordDecl>(RD);
909       CXXRecordDecl::base_class_const_iterator BI = CD->bases_begin();
910       for (unsigned I = 0; I != N; ++I, ++BI) {
911         assert(BI != CD->bases_end());
912         if (!First)
913           Out << ", ";
914         getStructBase(I).printPretty(Out, Policy, BI->getType(), Ctx);
915         First = false;
916       }
917     }
918     for (const auto *FI : RD->fields()) {
919       if (!First)
920         Out << ", ";
921       if (FI->isUnnamedBitField())
922         continue;
923       getStructField(FI->getFieldIndex()).
924         printPretty(Out, Policy, FI->getType(), Ctx);
925       First = false;
926     }
927     Out << '}';
928     return;
929   }
930   case APValue::Union:
931     Out << '{';
932     if (const FieldDecl *FD = getUnionField()) {
933       Out << "." << *FD << " = ";
934       getUnionValue().printPretty(Out, Policy, FD->getType(), Ctx);
935     }
936     Out << '}';
937     return;
938   case APValue::MemberPointer:
939     // FIXME: This is not enough to unambiguously identify the member in a
940     // multiple-inheritance scenario.
941     if (const ValueDecl *VD = getMemberPointerDecl()) {
942       Out << '&' << *cast<CXXRecordDecl>(VD->getDeclContext()) << "::" << *VD;
943       return;
944     }
945     Out << "0";
946     return;
947   case APValue::AddrLabelDiff:
948     Out << "&&" << getAddrLabelDiffLHS()->getLabel()->getName();
949     Out << " - ";
950     Out << "&&" << getAddrLabelDiffRHS()->getLabel()->getName();
951     return;
952   }
953   llvm_unreachable("Unknown APValue kind!");
954 }
955 
956 std::string APValue::getAsString(const ASTContext &Ctx, QualType Ty) const {
957   std::string Result;
958   llvm::raw_string_ostream Out(Result);
959   printPretty(Out, Ctx, Ty);
960   return Result;
961 }
962 
963 bool APValue::toIntegralConstant(APSInt &Result, QualType SrcTy,
964                                  const ASTContext &Ctx) const {
965   if (isInt()) {
966     Result = getInt();
967     return true;
968   }
969 
970   if (isLValue() && isNullPointer()) {
971     Result = Ctx.MakeIntValue(Ctx.getTargetNullPointerValue(SrcTy), SrcTy);
972     return true;
973   }
974 
975   if (isLValue() && !getLValueBase()) {
976     Result = Ctx.MakeIntValue(getLValueOffset().getQuantity(), SrcTy);
977     return true;
978   }
979 
980   return false;
981 }
982 
983 const APValue::LValueBase APValue::getLValueBase() const {
984   assert(isLValue() && "Invalid accessor");
985   return ((const LV *)(const void *)&Data)->Base;
986 }
987 
988 bool APValue::isLValueOnePastTheEnd() const {
989   assert(isLValue() && "Invalid accessor");
990   return ((const LV *)(const void *)&Data)->IsOnePastTheEnd;
991 }
992 
993 CharUnits &APValue::getLValueOffset() {
994   assert(isLValue() && "Invalid accessor");
995   return ((LV *)(void *)&Data)->Offset;
996 }
997 
998 bool APValue::hasLValuePath() const {
999   assert(isLValue() && "Invalid accessor");
1000   return ((const LV *)(const char *)&Data)->hasPath();
1001 }
1002 
1003 ArrayRef<APValue::LValuePathEntry> APValue::getLValuePath() const {
1004   assert(isLValue() && hasLValuePath() && "Invalid accessor");
1005   const LV &LVal = *((const LV *)(const char *)&Data);
1006   return {LVal.getPath(), LVal.PathLength};
1007 }
1008 
1009 unsigned APValue::getLValueCallIndex() const {
1010   assert(isLValue() && "Invalid accessor");
1011   return ((const LV *)(const char *)&Data)->Base.getCallIndex();
1012 }
1013 
1014 unsigned APValue::getLValueVersion() const {
1015   assert(isLValue() && "Invalid accessor");
1016   return ((const LV *)(const char *)&Data)->Base.getVersion();
1017 }
1018 
1019 bool APValue::isNullPointer() const {
1020   assert(isLValue() && "Invalid usage");
1021   return ((const LV *)(const char *)&Data)->IsNullPtr;
1022 }
1023 
1024 void APValue::setLValue(LValueBase B, const CharUnits &O, NoLValuePath,
1025                         bool IsNullPtr) {
1026   assert(isLValue() && "Invalid accessor");
1027   LV &LVal = *((LV *)(char *)&Data);
1028   LVal.Base = B;
1029   LVal.IsOnePastTheEnd = false;
1030   LVal.Offset = O;
1031   LVal.resizePath((unsigned)-1);
1032   LVal.IsNullPtr = IsNullPtr;
1033 }
1034 
1035 MutableArrayRef<APValue::LValuePathEntry>
1036 APValue::setLValueUninit(LValueBase B, const CharUnits &O, unsigned Size,
1037                          bool IsOnePastTheEnd, bool IsNullPtr) {
1038   assert(isLValue() && "Invalid accessor");
1039   LV &LVal = *((LV *)(char *)&Data);
1040   LVal.Base = B;
1041   LVal.IsOnePastTheEnd = IsOnePastTheEnd;
1042   LVal.Offset = O;
1043   LVal.IsNullPtr = IsNullPtr;
1044   LVal.resizePath(Size);
1045   return {LVal.getPath(), Size};
1046 }
1047 
1048 void APValue::setLValue(LValueBase B, const CharUnits &O,
1049                         ArrayRef<LValuePathEntry> Path, bool IsOnePastTheEnd,
1050                         bool IsNullPtr) {
1051   MutableArrayRef<APValue::LValuePathEntry> InternalPath =
1052       setLValueUninit(B, O, Path.size(), IsOnePastTheEnd, IsNullPtr);
1053   if (Path.size()) {
1054     memcpy(InternalPath.data(), Path.data(),
1055            Path.size() * sizeof(LValuePathEntry));
1056   }
1057 }
1058 
1059 void APValue::setUnion(const FieldDecl *Field, const APValue &Value) {
1060   assert(isUnion() && "Invalid accessor");
1061   ((UnionData *)(char *)&Data)->Field =
1062       Field ? Field->getCanonicalDecl() : nullptr;
1063   *((UnionData *)(char *)&Data)->Value = Value;
1064 }
1065 
1066 const ValueDecl *APValue::getMemberPointerDecl() const {
1067   assert(isMemberPointer() && "Invalid accessor");
1068   const MemberPointerData &MPD =
1069       *((const MemberPointerData *)(const char *)&Data);
1070   return MPD.MemberAndIsDerivedMember.getPointer();
1071 }
1072 
1073 bool APValue::isMemberPointerToDerivedMember() const {
1074   assert(isMemberPointer() && "Invalid accessor");
1075   const MemberPointerData &MPD =
1076       *((const MemberPointerData *)(const char *)&Data);
1077   return MPD.MemberAndIsDerivedMember.getInt();
1078 }
1079 
1080 ArrayRef<const CXXRecordDecl*> APValue::getMemberPointerPath() const {
1081   assert(isMemberPointer() && "Invalid accessor");
1082   const MemberPointerData &MPD =
1083       *((const MemberPointerData *)(const char *)&Data);
1084   return {MPD.getPath(), MPD.PathLength};
1085 }
1086 
1087 void APValue::MakeLValue() {
1088   assert(isAbsent() && "Bad state change");
1089   static_assert(sizeof(LV) <= DataSize, "LV too big");
1090   new ((void *)(char *)&Data) LV();
1091   Kind = LValue;
1092 }
1093 
1094 void APValue::MakeArray(unsigned InitElts, unsigned Size) {
1095   assert(isAbsent() && "Bad state change");
1096   new ((void *)(char *)&Data) Arr(InitElts, Size);
1097   Kind = Array;
1098 }
1099 
1100 MutableArrayRef<const CXXRecordDecl *>
1101 APValue::setMemberPointerUninit(const ValueDecl *Member, bool IsDerivedMember,
1102                                 unsigned Size) {
1103   assert(isAbsent() && "Bad state change");
1104   MemberPointerData *MPD = new ((void *)(char *)&Data) MemberPointerData;
1105   Kind = MemberPointer;
1106   MPD->MemberAndIsDerivedMember.setPointer(
1107       Member ? cast<ValueDecl>(Member->getCanonicalDecl()) : nullptr);
1108   MPD->MemberAndIsDerivedMember.setInt(IsDerivedMember);
1109   MPD->resizePath(Size);
1110   return {MPD->getPath(), MPD->PathLength};
1111 }
1112 
1113 void APValue::MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
1114                                 ArrayRef<const CXXRecordDecl *> Path) {
1115   MutableArrayRef<const CXXRecordDecl *> InternalPath =
1116       setMemberPointerUninit(Member, IsDerivedMember, Path.size());
1117   for (unsigned I = 0; I != Path.size(); ++I)
1118     InternalPath[I] = Path[I]->getCanonicalDecl();
1119 }
1120 
1121 LinkageInfo LinkageComputer::getLVForValue(const APValue &V,
1122                                            LVComputationKind computation) {
1123   LinkageInfo LV = LinkageInfo::external();
1124 
1125   auto MergeLV = [&](LinkageInfo MergeLV) {
1126     LV.merge(MergeLV);
1127     return LV.getLinkage() == Linkage::Internal;
1128   };
1129   auto Merge = [&](const APValue &V) {
1130     return MergeLV(getLVForValue(V, computation));
1131   };
1132 
1133   switch (V.getKind()) {
1134   case APValue::None:
1135   case APValue::Indeterminate:
1136   case APValue::Int:
1137   case APValue::Float:
1138   case APValue::FixedPoint:
1139   case APValue::ComplexInt:
1140   case APValue::ComplexFloat:
1141   case APValue::Vector:
1142     break;
1143 
1144   case APValue::AddrLabelDiff:
1145     // Even for an inline function, it's not reasonable to treat a difference
1146     // between the addresses of labels as an external value.
1147     return LinkageInfo::internal();
1148 
1149   case APValue::Struct: {
1150     for (unsigned I = 0, N = V.getStructNumBases(); I != N; ++I)
1151       if (Merge(V.getStructBase(I)))
1152         break;
1153     for (unsigned I = 0, N = V.getStructNumFields(); I != N; ++I)
1154       if (Merge(V.getStructField(I)))
1155         break;
1156     break;
1157   }
1158 
1159   case APValue::Union:
1160     if (V.getUnionField())
1161       Merge(V.getUnionValue());
1162     break;
1163 
1164   case APValue::Array: {
1165     for (unsigned I = 0, N = V.getArrayInitializedElts(); I != N; ++I)
1166       if (Merge(V.getArrayInitializedElt(I)))
1167         break;
1168     if (V.hasArrayFiller())
1169       Merge(V.getArrayFiller());
1170     break;
1171   }
1172 
1173   case APValue::LValue: {
1174     if (!V.getLValueBase()) {
1175       // Null or absolute address: this is external.
1176     } else if (const auto *VD =
1177                    V.getLValueBase().dyn_cast<const ValueDecl *>()) {
1178       if (VD && MergeLV(getLVForDecl(VD, computation)))
1179         break;
1180     } else if (const auto TI = V.getLValueBase().dyn_cast<TypeInfoLValue>()) {
1181       if (MergeLV(getLVForType(*TI.getType(), computation)))
1182         break;
1183     } else if (const Expr *E = V.getLValueBase().dyn_cast<const Expr *>()) {
1184       // Almost all expression bases are internal. The exception is
1185       // lifetime-extended temporaries.
1186       // FIXME: These should be modeled as having the
1187       // LifetimeExtendedTemporaryDecl itself as the base.
1188       // FIXME: If we permit Objective-C object literals in template arguments,
1189       // they should not imply internal linkage.
1190       auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E);
1191       if (!MTE || MTE->getStorageDuration() == SD_FullExpression)
1192         return LinkageInfo::internal();
1193       if (MergeLV(getLVForDecl(MTE->getExtendingDecl(), computation)))
1194         break;
1195     } else {
1196       assert(V.getLValueBase().is<DynamicAllocLValue>() &&
1197              "unexpected LValueBase kind");
1198       return LinkageInfo::internal();
1199     }
1200     // The lvalue path doesn't matter: pointers to all subobjects always have
1201     // the same visibility as pointers to the complete object.
1202     break;
1203   }
1204 
1205   case APValue::MemberPointer:
1206     if (const NamedDecl *D = V.getMemberPointerDecl())
1207       MergeLV(getLVForDecl(D, computation));
1208     // Note that we could have a base-to-derived conversion here to a member of
1209     // a derived class with less linkage/visibility. That's covered by the
1210     // linkage and visibility of the value's type.
1211     break;
1212   }
1213 
1214   return LV;
1215 }
1216