1 //===- DebugInfoMetadata.cpp - Implement debug info metadata --------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the debug info Metadata classes.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/IR/DebugInfoMetadata.h"
15 #include "LLVMContextImpl.h"
16 #include "MetadataImpl.h"
17 #include "llvm/ADT/SmallSet.h"
18 #include "llvm/ADT/StringSwitch.h"
19 #include "llvm/IR/DIBuilder.h"
20 #include "llvm/IR/Function.h"
21 #include "llvm/IR/Instructions.h"
22 
23 using namespace llvm;
24 
25 DILocation::DILocation(LLVMContext &C, StorageType Storage, unsigned Line,
26                        unsigned Column, ArrayRef<Metadata *> MDs,
27                        bool ImplicitCode)
28     : MDNode(C, DILocationKind, Storage, MDs) {
29   assert((MDs.size() == 1 || MDs.size() == 2) &&
30          "Expected a scope and optional inlined-at");
31 
32   // Set line and column.
33   assert(Column < (1u << 16) && "Expected 16-bit column");
34 
35   SubclassData32 = Line;
36   SubclassData16 = Column;
37 
38   setImplicitCode(ImplicitCode);
39 }
40 
41 static void adjustColumn(unsigned &Column) {
42   // Set to unknown on overflow.  We only have 16 bits to play with here.
43   if (Column >= (1u << 16))
44     Column = 0;
45 }
46 
47 DILocation *DILocation::getImpl(LLVMContext &Context, unsigned Line,
48                                 unsigned Column, Metadata *Scope,
49                                 Metadata *InlinedAt, bool ImplicitCode,
50                                 StorageType Storage, bool ShouldCreate) {
51   // Fixup column.
52   adjustColumn(Column);
53 
54   if (Storage == Uniqued) {
55     if (auto *N = getUniqued(Context.pImpl->DILocations,
56                              DILocationInfo::KeyTy(Line, Column, Scope,
57                                                    InlinedAt, ImplicitCode)))
58       return N;
59     if (!ShouldCreate)
60       return nullptr;
61   } else {
62     assert(ShouldCreate && "Expected non-uniqued nodes to always be created");
63   }
64 
65   SmallVector<Metadata *, 2> Ops;
66   Ops.push_back(Scope);
67   if (InlinedAt)
68     Ops.push_back(InlinedAt);
69   return storeImpl(new (Ops.size()) DILocation(Context, Storage, Line, Column,
70                                                Ops, ImplicitCode),
71                    Storage, Context.pImpl->DILocations);
72 }
73 
74 const DILocation *DILocation::getMergedLocation(const DILocation *LocA,
75                                                 const DILocation *LocB) {
76   if (!LocA || !LocB)
77     return nullptr;
78 
79   if (LocA == LocB)
80     return LocA;
81 
82   SmallPtrSet<DILocation *, 5> InlinedLocationsA;
83   for (DILocation *L = LocA->getInlinedAt(); L; L = L->getInlinedAt())
84     InlinedLocationsA.insert(L);
85   SmallSet<std::pair<DIScope *, DILocation *>, 5> Locations;
86   DIScope *S = LocA->getScope();
87   DILocation *L = LocA->getInlinedAt();
88   while (S) {
89     Locations.insert(std::make_pair(S, L));
90     S = S->getScope().resolve();
91     if (!S && L) {
92       S = L->getScope();
93       L = L->getInlinedAt();
94     }
95   }
96   const DILocation *Result = LocB;
97   S = LocB->getScope();
98   L = LocB->getInlinedAt();
99   while (S) {
100     if (Locations.count(std::make_pair(S, L)))
101       break;
102     S = S->getScope().resolve();
103     if (!S && L) {
104       S = L->getScope();
105       L = L->getInlinedAt();
106     }
107   }
108 
109   // If the two locations are irreconsilable, just pick one. This is misleading,
110   // but on the other hand, it's a "line 0" location.
111   if (!S || !isa<DILocalScope>(S))
112     S = LocA->getScope();
113   return DILocation::get(Result->getContext(), 0, 0, S, L);
114 }
115 
116 DINode::DIFlags DINode::getFlag(StringRef Flag) {
117   return StringSwitch<DIFlags>(Flag)
118 #define HANDLE_DI_FLAG(ID, NAME) .Case("DIFlag" #NAME, Flag##NAME)
119 #include "llvm/IR/DebugInfoFlags.def"
120       .Default(DINode::FlagZero);
121 }
122 
123 StringRef DINode::getFlagString(DIFlags Flag) {
124   switch (Flag) {
125 #define HANDLE_DI_FLAG(ID, NAME)                                               \
126   case Flag##NAME:                                                             \
127     return "DIFlag" #NAME;
128 #include "llvm/IR/DebugInfoFlags.def"
129   }
130   return "";
131 }
132 
133 DINode::DIFlags DINode::splitFlags(DIFlags Flags,
134                                    SmallVectorImpl<DIFlags> &SplitFlags) {
135   // Flags that are packed together need to be specially handled, so
136   // that, for example, we emit "DIFlagPublic" and not
137   // "DIFlagPrivate | DIFlagProtected".
138   if (DIFlags A = Flags & FlagAccessibility) {
139     if (A == FlagPrivate)
140       SplitFlags.push_back(FlagPrivate);
141     else if (A == FlagProtected)
142       SplitFlags.push_back(FlagProtected);
143     else
144       SplitFlags.push_back(FlagPublic);
145     Flags &= ~A;
146   }
147   if (DIFlags R = Flags & FlagPtrToMemberRep) {
148     if (R == FlagSingleInheritance)
149       SplitFlags.push_back(FlagSingleInheritance);
150     else if (R == FlagMultipleInheritance)
151       SplitFlags.push_back(FlagMultipleInheritance);
152     else
153       SplitFlags.push_back(FlagVirtualInheritance);
154     Flags &= ~R;
155   }
156   if ((Flags & FlagIndirectVirtualBase) == FlagIndirectVirtualBase) {
157     Flags &= ~FlagIndirectVirtualBase;
158     SplitFlags.push_back(FlagIndirectVirtualBase);
159   }
160 
161 #define HANDLE_DI_FLAG(ID, NAME)                                               \
162   if (DIFlags Bit = Flags & Flag##NAME) {                                      \
163     SplitFlags.push_back(Bit);                                                 \
164     Flags &= ~Bit;                                                             \
165   }
166 #include "llvm/IR/DebugInfoFlags.def"
167   return Flags;
168 }
169 
170 DIScopeRef DIScope::getScope() const {
171   if (auto *T = dyn_cast<DIType>(this))
172     return T->getScope();
173 
174   if (auto *SP = dyn_cast<DISubprogram>(this))
175     return SP->getScope();
176 
177   if (auto *LB = dyn_cast<DILexicalBlockBase>(this))
178     return LB->getScope();
179 
180   if (auto *NS = dyn_cast<DINamespace>(this))
181     return NS->getScope();
182 
183   if (auto *M = dyn_cast<DIModule>(this))
184     return M->getScope();
185 
186   assert((isa<DIFile>(this) || isa<DICompileUnit>(this)) &&
187          "Unhandled type of scope.");
188   return nullptr;
189 }
190 
191 StringRef DIScope::getName() const {
192   if (auto *T = dyn_cast<DIType>(this))
193     return T->getName();
194   if (auto *SP = dyn_cast<DISubprogram>(this))
195     return SP->getName();
196   if (auto *NS = dyn_cast<DINamespace>(this))
197     return NS->getName();
198   if (auto *M = dyn_cast<DIModule>(this))
199     return M->getName();
200   assert((isa<DILexicalBlockBase>(this) || isa<DIFile>(this) ||
201           isa<DICompileUnit>(this)) &&
202          "Unhandled type of scope.");
203   return "";
204 }
205 
206 #ifndef NDEBUG
207 static bool isCanonical(const MDString *S) {
208   return !S || !S->getString().empty();
209 }
210 #endif
211 
212 GenericDINode *GenericDINode::getImpl(LLVMContext &Context, unsigned Tag,
213                                       MDString *Header,
214                                       ArrayRef<Metadata *> DwarfOps,
215                                       StorageType Storage, bool ShouldCreate) {
216   unsigned Hash = 0;
217   if (Storage == Uniqued) {
218     GenericDINodeInfo::KeyTy Key(Tag, Header, DwarfOps);
219     if (auto *N = getUniqued(Context.pImpl->GenericDINodes, Key))
220       return N;
221     if (!ShouldCreate)
222       return nullptr;
223     Hash = Key.getHash();
224   } else {
225     assert(ShouldCreate && "Expected non-uniqued nodes to always be created");
226   }
227 
228   // Use a nullptr for empty headers.
229   assert(isCanonical(Header) && "Expected canonical MDString");
230   Metadata *PreOps[] = {Header};
231   return storeImpl(new (DwarfOps.size() + 1) GenericDINode(
232                        Context, Storage, Hash, Tag, PreOps, DwarfOps),
233                    Storage, Context.pImpl->GenericDINodes);
234 }
235 
236 void GenericDINode::recalculateHash() {
237   setHash(GenericDINodeInfo::KeyTy::calculateHash(this));
238 }
239 
240 #define UNWRAP_ARGS_IMPL(...) __VA_ARGS__
241 #define UNWRAP_ARGS(ARGS) UNWRAP_ARGS_IMPL ARGS
242 #define DEFINE_GETIMPL_LOOKUP(CLASS, ARGS)                                     \
243   do {                                                                         \
244     if (Storage == Uniqued) {                                                  \
245       if (auto *N = getUniqued(Context.pImpl->CLASS##s,                        \
246                                CLASS##Info::KeyTy(UNWRAP_ARGS(ARGS))))         \
247         return N;                                                              \
248       if (!ShouldCreate)                                                       \
249         return nullptr;                                                        \
250     } else {                                                                   \
251       assert(ShouldCreate &&                                                   \
252              "Expected non-uniqued nodes to always be created");               \
253     }                                                                          \
254   } while (false)
255 #define DEFINE_GETIMPL_STORE(CLASS, ARGS, OPS)                                 \
256   return storeImpl(new (array_lengthof(OPS))                                   \
257                        CLASS(Context, Storage, UNWRAP_ARGS(ARGS), OPS),        \
258                    Storage, Context.pImpl->CLASS##s)
259 #define DEFINE_GETIMPL_STORE_NO_OPS(CLASS, ARGS)                               \
260   return storeImpl(new (0u) CLASS(Context, Storage, UNWRAP_ARGS(ARGS)),        \
261                    Storage, Context.pImpl->CLASS##s)
262 #define DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(CLASS, OPS)                   \
263   return storeImpl(new (array_lengthof(OPS)) CLASS(Context, Storage, OPS),     \
264                    Storage, Context.pImpl->CLASS##s)
265 #define DEFINE_GETIMPL_STORE_N(CLASS, ARGS, OPS, NUM_OPS)                      \
266   return storeImpl(new (NUM_OPS)                                               \
267                        CLASS(Context, Storage, UNWRAP_ARGS(ARGS), OPS),        \
268                    Storage, Context.pImpl->CLASS##s)
269 
270 DISubrange *DISubrange::getImpl(LLVMContext &Context, int64_t Count, int64_t Lo,
271                                 StorageType Storage, bool ShouldCreate) {
272   auto *CountNode = ConstantAsMetadata::get(
273       ConstantInt::getSigned(Type::getInt64Ty(Context), Count));
274   return getImpl(Context, CountNode, Lo, Storage, ShouldCreate);
275 }
276 
277 DISubrange *DISubrange::getImpl(LLVMContext &Context, Metadata *CountNode,
278                                 int64_t Lo, StorageType Storage,
279                                 bool ShouldCreate) {
280   DEFINE_GETIMPL_LOOKUP(DISubrange, (CountNode, Lo));
281   Metadata *Ops[] = { CountNode };
282   DEFINE_GETIMPL_STORE(DISubrange, (CountNode, Lo), Ops);
283 }
284 
285 DIEnumerator *DIEnumerator::getImpl(LLVMContext &Context, int64_t Value,
286                                     bool IsUnsigned, MDString *Name,
287                                     StorageType Storage, bool ShouldCreate) {
288   assert(isCanonical(Name) && "Expected canonical MDString");
289   DEFINE_GETIMPL_LOOKUP(DIEnumerator, (Value, IsUnsigned, Name));
290   Metadata *Ops[] = {Name};
291   DEFINE_GETIMPL_STORE(DIEnumerator, (Value, IsUnsigned), Ops);
292 }
293 
294 DIBasicType *DIBasicType::getImpl(LLVMContext &Context, unsigned Tag,
295                                   MDString *Name, uint64_t SizeInBits,
296                                   uint32_t AlignInBits, unsigned Encoding,
297                                   DIFlags Flags, StorageType Storage,
298                                   bool ShouldCreate) {
299   assert(isCanonical(Name) && "Expected canonical MDString");
300   DEFINE_GETIMPL_LOOKUP(DIBasicType,
301                         (Tag, Name, SizeInBits, AlignInBits, Encoding, Flags));
302   Metadata *Ops[] = {nullptr, nullptr, Name};
303   DEFINE_GETIMPL_STORE(DIBasicType, (Tag, SizeInBits, AlignInBits, Encoding,
304                       Flags), Ops);
305 }
306 
307 Optional<DIBasicType::Signedness> DIBasicType::getSignedness() const {
308   switch (getEncoding()) {
309   case dwarf::DW_ATE_signed:
310   case dwarf::DW_ATE_signed_char:
311     return Signedness::Signed;
312   case dwarf::DW_ATE_unsigned:
313   case dwarf::DW_ATE_unsigned_char:
314     return Signedness::Unsigned;
315   default:
316     return None;
317   }
318 }
319 
320 DIDerivedType *DIDerivedType::getImpl(
321     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *File,
322     unsigned Line, Metadata *Scope, Metadata *BaseType, uint64_t SizeInBits,
323     uint32_t AlignInBits, uint64_t OffsetInBits,
324     Optional<unsigned> DWARFAddressSpace, DIFlags Flags, Metadata *ExtraData,
325     StorageType Storage, bool ShouldCreate) {
326   assert(isCanonical(Name) && "Expected canonical MDString");
327   DEFINE_GETIMPL_LOOKUP(DIDerivedType,
328                         (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
329                          AlignInBits, OffsetInBits, DWARFAddressSpace, Flags,
330                          ExtraData));
331   Metadata *Ops[] = {File, Scope, Name, BaseType, ExtraData};
332   DEFINE_GETIMPL_STORE(
333       DIDerivedType, (Tag, Line, SizeInBits, AlignInBits, OffsetInBits,
334                       DWARFAddressSpace, Flags), Ops);
335 }
336 
337 DICompositeType *DICompositeType::getImpl(
338     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *File,
339     unsigned Line, Metadata *Scope, Metadata *BaseType, uint64_t SizeInBits,
340     uint32_t AlignInBits, uint64_t OffsetInBits, DIFlags Flags,
341     Metadata *Elements, unsigned RuntimeLang, Metadata *VTableHolder,
342     Metadata *TemplateParams, MDString *Identifier, Metadata *Discriminator,
343     StorageType Storage, bool ShouldCreate) {
344   assert(isCanonical(Name) && "Expected canonical MDString");
345 
346   // Keep this in sync with buildODRType.
347   DEFINE_GETIMPL_LOOKUP(
348       DICompositeType, (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
349                         AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang,
350                         VTableHolder, TemplateParams, Identifier, Discriminator));
351   Metadata *Ops[] = {File,     Scope,        Name,           BaseType,
352                      Elements, VTableHolder, TemplateParams, Identifier,
353                      Discriminator};
354   DEFINE_GETIMPL_STORE(DICompositeType, (Tag, Line, RuntimeLang, SizeInBits,
355                                          AlignInBits, OffsetInBits, Flags),
356                        Ops);
357 }
358 
359 DICompositeType *DICompositeType::buildODRType(
360     LLVMContext &Context, MDString &Identifier, unsigned Tag, MDString *Name,
361     Metadata *File, unsigned Line, Metadata *Scope, Metadata *BaseType,
362     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
363     DIFlags Flags, Metadata *Elements, unsigned RuntimeLang,
364     Metadata *VTableHolder, Metadata *TemplateParams, Metadata *Discriminator) {
365   assert(!Identifier.getString().empty() && "Expected valid identifier");
366   if (!Context.isODRUniquingDebugTypes())
367     return nullptr;
368   auto *&CT = (*Context.pImpl->DITypeMap)[&Identifier];
369   if (!CT)
370     return CT = DICompositeType::getDistinct(
371                Context, Tag, Name, File, Line, Scope, BaseType, SizeInBits,
372                AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang,
373                VTableHolder, TemplateParams, &Identifier, Discriminator);
374 
375   // Only mutate CT if it's a forward declaration and the new operands aren't.
376   assert(CT->getRawIdentifier() == &Identifier && "Wrong ODR identifier?");
377   if (!CT->isForwardDecl() || (Flags & DINode::FlagFwdDecl))
378     return CT;
379 
380   // Mutate CT in place.  Keep this in sync with getImpl.
381   CT->mutate(Tag, Line, RuntimeLang, SizeInBits, AlignInBits, OffsetInBits,
382              Flags);
383   Metadata *Ops[] = {File,     Scope,        Name,           BaseType,
384                      Elements, VTableHolder, TemplateParams, &Identifier,
385                      Discriminator};
386   assert((std::end(Ops) - std::begin(Ops)) == (int)CT->getNumOperands() &&
387          "Mismatched number of operands");
388   for (unsigned I = 0, E = CT->getNumOperands(); I != E; ++I)
389     if (Ops[I] != CT->getOperand(I))
390       CT->setOperand(I, Ops[I]);
391   return CT;
392 }
393 
394 DICompositeType *DICompositeType::getODRType(
395     LLVMContext &Context, MDString &Identifier, unsigned Tag, MDString *Name,
396     Metadata *File, unsigned Line, Metadata *Scope, Metadata *BaseType,
397     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
398     DIFlags Flags, Metadata *Elements, unsigned RuntimeLang,
399     Metadata *VTableHolder, Metadata *TemplateParams, Metadata *Discriminator) {
400   assert(!Identifier.getString().empty() && "Expected valid identifier");
401   if (!Context.isODRUniquingDebugTypes())
402     return nullptr;
403   auto *&CT = (*Context.pImpl->DITypeMap)[&Identifier];
404   if (!CT)
405     CT = DICompositeType::getDistinct(
406         Context, Tag, Name, File, Line, Scope, BaseType, SizeInBits,
407         AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang, VTableHolder,
408         TemplateParams, &Identifier, Discriminator);
409   return CT;
410 }
411 
412 DICompositeType *DICompositeType::getODRTypeIfExists(LLVMContext &Context,
413                                                      MDString &Identifier) {
414   assert(!Identifier.getString().empty() && "Expected valid identifier");
415   if (!Context.isODRUniquingDebugTypes())
416     return nullptr;
417   return Context.pImpl->DITypeMap->lookup(&Identifier);
418 }
419 
420 DISubroutineType *DISubroutineType::getImpl(LLVMContext &Context, DIFlags Flags,
421                                             uint8_t CC, Metadata *TypeArray,
422                                             StorageType Storage,
423                                             bool ShouldCreate) {
424   DEFINE_GETIMPL_LOOKUP(DISubroutineType, (Flags, CC, TypeArray));
425   Metadata *Ops[] = {nullptr, nullptr, nullptr, TypeArray};
426   DEFINE_GETIMPL_STORE(DISubroutineType, (Flags, CC), Ops);
427 }
428 
429 // FIXME: Implement this string-enum correspondence with a .def file and macros,
430 // so that the association is explicit rather than implied.
431 static const char *ChecksumKindName[DIFile::CSK_Last] = {
432   "CSK_MD5",
433   "CSK_SHA1"
434 };
435 
436 StringRef DIFile::getChecksumKindAsString(ChecksumKind CSKind) {
437   assert(CSKind <= DIFile::CSK_Last && "Invalid checksum kind");
438   // The first space was originally the CSK_None variant, which is now
439   // obsolete, but the space is still reserved in ChecksumKind, so we account
440   // for it here.
441   return ChecksumKindName[CSKind - 1];
442 }
443 
444 Optional<DIFile::ChecksumKind> DIFile::getChecksumKind(StringRef CSKindStr) {
445   return StringSwitch<Optional<DIFile::ChecksumKind>>(CSKindStr)
446       .Case("CSK_MD5", DIFile::CSK_MD5)
447       .Case("CSK_SHA1", DIFile::CSK_SHA1)
448       .Default(None);
449 }
450 
451 DIFile *DIFile::getImpl(LLVMContext &Context, MDString *Filename,
452                         MDString *Directory,
453                         Optional<DIFile::ChecksumInfo<MDString *>> CS,
454                         Optional<MDString *> Source, StorageType Storage,
455                         bool ShouldCreate) {
456   assert(isCanonical(Filename) && "Expected canonical MDString");
457   assert(isCanonical(Directory) && "Expected canonical MDString");
458   assert((!CS || isCanonical(CS->Value)) && "Expected canonical MDString");
459   assert((!Source || isCanonical(*Source)) && "Expected canonical MDString");
460   DEFINE_GETIMPL_LOOKUP(DIFile, (Filename, Directory, CS, Source));
461   Metadata *Ops[] = {Filename, Directory, CS ? CS->Value : nullptr,
462                      Source.getValueOr(nullptr)};
463   DEFINE_GETIMPL_STORE(DIFile, (CS, Source), Ops);
464 }
465 
466 DICompileUnit *DICompileUnit::getImpl(
467     LLVMContext &Context, unsigned SourceLanguage, Metadata *File,
468     MDString *Producer, bool IsOptimized, MDString *Flags,
469     unsigned RuntimeVersion, MDString *SplitDebugFilename,
470     unsigned EmissionKind, Metadata *EnumTypes, Metadata *RetainedTypes,
471     Metadata *GlobalVariables, Metadata *ImportedEntities, Metadata *Macros,
472     uint64_t DWOId, bool SplitDebugInlining, bool DebugInfoForProfiling,
473     unsigned NameTableKind, bool RangesBaseAddress, StorageType Storage,
474     bool ShouldCreate) {
475   assert(Storage != Uniqued && "Cannot unique DICompileUnit");
476   assert(isCanonical(Producer) && "Expected canonical MDString");
477   assert(isCanonical(Flags) && "Expected canonical MDString");
478   assert(isCanonical(SplitDebugFilename) && "Expected canonical MDString");
479 
480   Metadata *Ops[] = {
481       File,      Producer,      Flags,           SplitDebugFilename,
482       EnumTypes, RetainedTypes, GlobalVariables, ImportedEntities,
483       Macros};
484   return storeImpl(new (array_lengthof(Ops)) DICompileUnit(
485                        Context, Storage, SourceLanguage, IsOptimized,
486                        RuntimeVersion, EmissionKind, DWOId, SplitDebugInlining,
487                        DebugInfoForProfiling, NameTableKind, RangesBaseAddress,
488                        Ops),
489                    Storage);
490 }
491 
492 Optional<DICompileUnit::DebugEmissionKind>
493 DICompileUnit::getEmissionKind(StringRef Str) {
494   return StringSwitch<Optional<DebugEmissionKind>>(Str)
495       .Case("NoDebug", NoDebug)
496       .Case("FullDebug", FullDebug)
497       .Case("LineTablesOnly", LineTablesOnly)
498       .Case("DebugDirectivesOnly", DebugDirectivesOnly)
499       .Default(None);
500 }
501 
502 Optional<DICompileUnit::DebugNameTableKind>
503 DICompileUnit::getNameTableKind(StringRef Str) {
504   return StringSwitch<Optional<DebugNameTableKind>>(Str)
505       .Case("Default", DebugNameTableKind::Default)
506       .Case("GNU", DebugNameTableKind::GNU)
507       .Case("None", DebugNameTableKind::None)
508       .Default(None);
509 }
510 
511 const char *DICompileUnit::emissionKindString(DebugEmissionKind EK) {
512   switch (EK) {
513   case NoDebug:        return "NoDebug";
514   case FullDebug:      return "FullDebug";
515   case LineTablesOnly: return "LineTablesOnly";
516   case DebugDirectivesOnly: return "DebugDirectivesOnly";
517   }
518   return nullptr;
519 }
520 
521 const char *DICompileUnit::nameTableKindString(DebugNameTableKind NTK) {
522   switch (NTK) {
523   case DebugNameTableKind::Default:
524     return nullptr;
525   case DebugNameTableKind::GNU:
526     return "GNU";
527   case DebugNameTableKind::None:
528     return "None";
529   }
530   return nullptr;
531 }
532 
533 DISubprogram *DILocalScope::getSubprogram() const {
534   if (auto *Block = dyn_cast<DILexicalBlockBase>(this))
535     return Block->getScope()->getSubprogram();
536   return const_cast<DISubprogram *>(cast<DISubprogram>(this));
537 }
538 
539 DILocalScope *DILocalScope::getNonLexicalBlockFileScope() const {
540   if (auto *File = dyn_cast<DILexicalBlockFile>(this))
541     return File->getScope()->getNonLexicalBlockFileScope();
542   return const_cast<DILocalScope *>(this);
543 }
544 
545 DISubprogram *DISubprogram::getImpl(
546     LLVMContext &Context, Metadata *Scope, MDString *Name,
547     MDString *LinkageName, Metadata *File, unsigned Line, Metadata *Type,
548     bool IsLocalToUnit, bool IsDefinition, unsigned ScopeLine,
549     Metadata *ContainingType, unsigned Virtuality, unsigned VirtualIndex,
550     int ThisAdjustment, DIFlags Flags, bool IsOptimized, Metadata *Unit,
551     Metadata *TemplateParams, Metadata *Declaration, Metadata *RetainedNodes,
552     Metadata *ThrownTypes, StorageType Storage, bool ShouldCreate) {
553   assert(isCanonical(Name) && "Expected canonical MDString");
554   assert(isCanonical(LinkageName) && "Expected canonical MDString");
555   DEFINE_GETIMPL_LOOKUP(
556       DISubprogram, (Scope, Name, LinkageName, File, Line, Type, IsLocalToUnit,
557                      IsDefinition, ScopeLine, ContainingType, Virtuality,
558                      VirtualIndex, ThisAdjustment, Flags, IsOptimized, Unit,
559                      TemplateParams, Declaration, RetainedNodes, ThrownTypes));
560   SmallVector<Metadata *, 11> Ops = {
561       File,        Scope,         Name,           LinkageName,    Type,       Unit,
562       Declaration, RetainedNodes, ContainingType, TemplateParams, ThrownTypes};
563   if (!ThrownTypes) {
564     Ops.pop_back();
565     if (!TemplateParams) {
566       Ops.pop_back();
567       if (!ContainingType)
568         Ops.pop_back();
569     }
570   }
571   DEFINE_GETIMPL_STORE_N(DISubprogram,
572                          (Line, ScopeLine, Virtuality, VirtualIndex,
573                           ThisAdjustment, Flags, IsLocalToUnit, IsDefinition,
574                           IsOptimized),
575                          Ops, Ops.size());
576 }
577 
578 bool DISubprogram::describes(const Function *F) const {
579   assert(F && "Invalid function");
580   if (F->getSubprogram() == this)
581     return true;
582   StringRef Name = getLinkageName();
583   if (Name.empty())
584     Name = getName();
585   return F->getName() == Name;
586 }
587 
588 DILexicalBlock *DILexicalBlock::getImpl(LLVMContext &Context, Metadata *Scope,
589                                         Metadata *File, unsigned Line,
590                                         unsigned Column, StorageType Storage,
591                                         bool ShouldCreate) {
592   // Fixup column.
593   adjustColumn(Column);
594 
595   assert(Scope && "Expected scope");
596   DEFINE_GETIMPL_LOOKUP(DILexicalBlock, (Scope, File, Line, Column));
597   Metadata *Ops[] = {File, Scope};
598   DEFINE_GETIMPL_STORE(DILexicalBlock, (Line, Column), Ops);
599 }
600 
601 DILexicalBlockFile *DILexicalBlockFile::getImpl(LLVMContext &Context,
602                                                 Metadata *Scope, Metadata *File,
603                                                 unsigned Discriminator,
604                                                 StorageType Storage,
605                                                 bool ShouldCreate) {
606   assert(Scope && "Expected scope");
607   DEFINE_GETIMPL_LOOKUP(DILexicalBlockFile, (Scope, File, Discriminator));
608   Metadata *Ops[] = {File, Scope};
609   DEFINE_GETIMPL_STORE(DILexicalBlockFile, (Discriminator), Ops);
610 }
611 
612 DINamespace *DINamespace::getImpl(LLVMContext &Context, Metadata *Scope,
613                                   MDString *Name, bool ExportSymbols,
614                                   StorageType Storage, bool ShouldCreate) {
615   assert(isCanonical(Name) && "Expected canonical MDString");
616   DEFINE_GETIMPL_LOOKUP(DINamespace, (Scope, Name, ExportSymbols));
617   // The nullptr is for DIScope's File operand. This should be refactored.
618   Metadata *Ops[] = {nullptr, Scope, Name};
619   DEFINE_GETIMPL_STORE(DINamespace, (ExportSymbols), Ops);
620 }
621 
622 DIModule *DIModule::getImpl(LLVMContext &Context, Metadata *Scope,
623                             MDString *Name, MDString *ConfigurationMacros,
624                             MDString *IncludePath, MDString *ISysRoot,
625                             StorageType Storage, bool ShouldCreate) {
626   assert(isCanonical(Name) && "Expected canonical MDString");
627   DEFINE_GETIMPL_LOOKUP(
628       DIModule, (Scope, Name, ConfigurationMacros, IncludePath, ISysRoot));
629   Metadata *Ops[] = {Scope, Name, ConfigurationMacros, IncludePath, ISysRoot};
630   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIModule, Ops);
631 }
632 
633 DITemplateTypeParameter *DITemplateTypeParameter::getImpl(LLVMContext &Context,
634                                                           MDString *Name,
635                                                           Metadata *Type,
636                                                           StorageType Storage,
637                                                           bool ShouldCreate) {
638   assert(isCanonical(Name) && "Expected canonical MDString");
639   DEFINE_GETIMPL_LOOKUP(DITemplateTypeParameter, (Name, Type));
640   Metadata *Ops[] = {Name, Type};
641   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DITemplateTypeParameter, Ops);
642 }
643 
644 DITemplateValueParameter *DITemplateValueParameter::getImpl(
645     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *Type,
646     Metadata *Value, StorageType Storage, bool ShouldCreate) {
647   assert(isCanonical(Name) && "Expected canonical MDString");
648   DEFINE_GETIMPL_LOOKUP(DITemplateValueParameter, (Tag, Name, Type, Value));
649   Metadata *Ops[] = {Name, Type, Value};
650   DEFINE_GETIMPL_STORE(DITemplateValueParameter, (Tag), Ops);
651 }
652 
653 DIGlobalVariable *
654 DIGlobalVariable::getImpl(LLVMContext &Context, Metadata *Scope, MDString *Name,
655                           MDString *LinkageName, Metadata *File, unsigned Line,
656                           Metadata *Type, bool IsLocalToUnit, bool IsDefinition,
657                           Metadata *StaticDataMemberDeclaration,
658                           Metadata *TemplateParams, uint32_t AlignInBits,
659                           StorageType Storage, bool ShouldCreate) {
660   assert(isCanonical(Name) && "Expected canonical MDString");
661   assert(isCanonical(LinkageName) && "Expected canonical MDString");
662   DEFINE_GETIMPL_LOOKUP(DIGlobalVariable, (Scope, Name, LinkageName, File, Line,
663                                            Type, IsLocalToUnit, IsDefinition,
664                                            StaticDataMemberDeclaration,
665                                            TemplateParams, AlignInBits));
666   Metadata *Ops[] = {Scope,
667                      Name,
668                      File,
669                      Type,
670                      Name,
671                      LinkageName,
672                      StaticDataMemberDeclaration,
673                      TemplateParams};
674   DEFINE_GETIMPL_STORE(DIGlobalVariable,
675                        (Line, IsLocalToUnit, IsDefinition, AlignInBits), Ops);
676 }
677 
678 DILocalVariable *DILocalVariable::getImpl(LLVMContext &Context, Metadata *Scope,
679                                           MDString *Name, Metadata *File,
680                                           unsigned Line, Metadata *Type,
681                                           unsigned Arg, DIFlags Flags,
682                                           uint32_t AlignInBits,
683                                           StorageType Storage,
684                                           bool ShouldCreate) {
685   // 64K ought to be enough for any frontend.
686   assert(Arg <= UINT16_MAX && "Expected argument number to fit in 16-bits");
687 
688   assert(Scope && "Expected scope");
689   assert(isCanonical(Name) && "Expected canonical MDString");
690   DEFINE_GETIMPL_LOOKUP(DILocalVariable,
691                         (Scope, Name, File, Line, Type, Arg, Flags,
692                          AlignInBits));
693   Metadata *Ops[] = {Scope, Name, File, Type};
694   DEFINE_GETIMPL_STORE(DILocalVariable, (Line, Arg, Flags, AlignInBits), Ops);
695 }
696 
697 Optional<uint64_t> DIVariable::getSizeInBits() const {
698   // This is used by the Verifier so be mindful of broken types.
699   const Metadata *RawType = getRawType();
700   while (RawType) {
701     // Try to get the size directly.
702     if (auto *T = dyn_cast<DIType>(RawType))
703       if (uint64_t Size = T->getSizeInBits())
704         return Size;
705 
706     if (auto *DT = dyn_cast<DIDerivedType>(RawType)) {
707       // Look at the base type.
708       RawType = DT->getRawBaseType();
709       continue;
710     }
711 
712     // Missing type or size.
713     break;
714   }
715 
716   // Fail gracefully.
717   return None;
718 }
719 
720 DILabel *DILabel::getImpl(LLVMContext &Context, Metadata *Scope,
721                           MDString *Name, Metadata *File, unsigned Line,
722                           StorageType Storage,
723                           bool ShouldCreate) {
724   assert(Scope && "Expected scope");
725   assert(isCanonical(Name) && "Expected canonical MDString");
726   DEFINE_GETIMPL_LOOKUP(DILabel,
727                         (Scope, Name, File, Line));
728   Metadata *Ops[] = {Scope, Name, File};
729   DEFINE_GETIMPL_STORE(DILabel, (Line), Ops);
730 }
731 
732 DIExpression *DIExpression::getImpl(LLVMContext &Context,
733                                     ArrayRef<uint64_t> Elements,
734                                     StorageType Storage, bool ShouldCreate) {
735   DEFINE_GETIMPL_LOOKUP(DIExpression, (Elements));
736   DEFINE_GETIMPL_STORE_NO_OPS(DIExpression, (Elements));
737 }
738 
739 unsigned DIExpression::ExprOperand::getSize() const {
740   switch (getOp()) {
741   case dwarf::DW_OP_LLVM_fragment:
742     return 3;
743   case dwarf::DW_OP_constu:
744   case dwarf::DW_OP_plus_uconst:
745     return 2;
746   default:
747     return 1;
748   }
749 }
750 
751 bool DIExpression::isValid() const {
752   for (auto I = expr_op_begin(), E = expr_op_end(); I != E; ++I) {
753     // Check that there's space for the operand.
754     if (I->get() + I->getSize() > E->get())
755       return false;
756 
757     // Check that the operand is valid.
758     switch (I->getOp()) {
759     default:
760       return false;
761     case dwarf::DW_OP_LLVM_fragment:
762       // A fragment operator must appear at the end.
763       return I->get() + I->getSize() == E->get();
764     case dwarf::DW_OP_stack_value: {
765       // Must be the last one or followed by a DW_OP_LLVM_fragment.
766       if (I->get() + I->getSize() == E->get())
767         break;
768       auto J = I;
769       if ((++J)->getOp() != dwarf::DW_OP_LLVM_fragment)
770         return false;
771       break;
772     }
773     case dwarf::DW_OP_swap: {
774       // Must be more than one implicit element on the stack.
775 
776       // FIXME: A better way to implement this would be to add a local variable
777       // that keeps track of the stack depth and introduce something like a
778       // DW_LLVM_OP_implicit_location as a placeholder for the location this
779       // DIExpression is attached to, or else pass the number of implicit stack
780       // elements into isValid.
781       if (getNumElements() == 1)
782         return false;
783       break;
784     }
785     case dwarf::DW_OP_constu:
786     case dwarf::DW_OP_plus_uconst:
787     case dwarf::DW_OP_plus:
788     case dwarf::DW_OP_minus:
789     case dwarf::DW_OP_mul:
790     case dwarf::DW_OP_div:
791     case dwarf::DW_OP_mod:
792     case dwarf::DW_OP_or:
793     case dwarf::DW_OP_and:
794     case dwarf::DW_OP_xor:
795     case dwarf::DW_OP_shl:
796     case dwarf::DW_OP_shr:
797     case dwarf::DW_OP_shra:
798     case dwarf::DW_OP_deref:
799     case dwarf::DW_OP_xderef:
800     case dwarf::DW_OP_lit0:
801     case dwarf::DW_OP_not:
802     case dwarf::DW_OP_dup:
803       break;
804     }
805   }
806   return true;
807 }
808 
809 Optional<DIExpression::FragmentInfo>
810 DIExpression::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) {
811   for (auto I = Start; I != End; ++I)
812     if (I->getOp() == dwarf::DW_OP_LLVM_fragment) {
813       DIExpression::FragmentInfo Info = {I->getArg(1), I->getArg(0)};
814       return Info;
815     }
816   return None;
817 }
818 
819 void DIExpression::appendOffset(SmallVectorImpl<uint64_t> &Ops,
820                                 int64_t Offset) {
821   if (Offset > 0) {
822     Ops.push_back(dwarf::DW_OP_plus_uconst);
823     Ops.push_back(Offset);
824   } else if (Offset < 0) {
825     Ops.push_back(dwarf::DW_OP_constu);
826     Ops.push_back(-Offset);
827     Ops.push_back(dwarf::DW_OP_minus);
828   }
829 }
830 
831 bool DIExpression::extractIfOffset(int64_t &Offset) const {
832   if (getNumElements() == 0) {
833     Offset = 0;
834     return true;
835   }
836 
837   if (getNumElements() == 2 && Elements[0] == dwarf::DW_OP_plus_uconst) {
838     Offset = Elements[1];
839     return true;
840   }
841 
842   if (getNumElements() == 3 && Elements[0] == dwarf::DW_OP_constu) {
843     if (Elements[2] == dwarf::DW_OP_plus) {
844       Offset = Elements[1];
845       return true;
846     }
847     if (Elements[2] == dwarf::DW_OP_minus) {
848       Offset = -Elements[1];
849       return true;
850     }
851   }
852 
853   return false;
854 }
855 
856 DIExpression *DIExpression::prepend(const DIExpression *Expr, bool DerefBefore,
857                                     int64_t Offset, bool DerefAfter,
858                                     bool StackValue) {
859   SmallVector<uint64_t, 8> Ops;
860   if (DerefBefore)
861     Ops.push_back(dwarf::DW_OP_deref);
862 
863   appendOffset(Ops, Offset);
864   if (DerefAfter)
865     Ops.push_back(dwarf::DW_OP_deref);
866 
867   return prependOpcodes(Expr, Ops, StackValue);
868 }
869 
870 DIExpression *DIExpression::prependOpcodes(const DIExpression *Expr,
871                                            SmallVectorImpl<uint64_t> &Ops,
872                                            bool StackValue) {
873   assert(Expr && "Can't prepend ops to this expression");
874 
875   // If there are no ops to prepend, do not even add the DW_OP_stack_value.
876   if (Ops.empty())
877     StackValue = false;
878   for (auto Op : Expr->expr_ops()) {
879     // A DW_OP_stack_value comes at the end, but before a DW_OP_LLVM_fragment.
880     if (StackValue) {
881       if (Op.getOp() == dwarf::DW_OP_stack_value)
882         StackValue = false;
883       else if (Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
884         Ops.push_back(dwarf::DW_OP_stack_value);
885         StackValue = false;
886       }
887     }
888     Op.appendToVector(Ops);
889   }
890   if (StackValue)
891     Ops.push_back(dwarf::DW_OP_stack_value);
892   return DIExpression::get(Expr->getContext(), Ops);
893 }
894 
895 DIExpression *DIExpression::append(const DIExpression *Expr,
896                                    ArrayRef<uint64_t> Ops) {
897   assert(Expr && !Ops.empty() && "Can't append ops to this expression");
898 
899   // Copy Expr's current op list.
900   SmallVector<uint64_t, 16> NewOps;
901   for (auto Op : Expr->expr_ops()) {
902     // Append new opcodes before DW_OP_{stack_value, LLVM_fragment}.
903     if (Op.getOp() == dwarf::DW_OP_stack_value ||
904         Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
905       NewOps.append(Ops.begin(), Ops.end());
906 
907       // Ensure that the new opcodes are only appended once.
908       Ops = None;
909     }
910     Op.appendToVector(NewOps);
911   }
912 
913   NewOps.append(Ops.begin(), Ops.end());
914   return DIExpression::get(Expr->getContext(), NewOps);
915 }
916 
917 DIExpression *DIExpression::appendToStack(const DIExpression *Expr,
918                                           ArrayRef<uint64_t> Ops) {
919   assert(Expr && !Ops.empty() && "Can't append ops to this expression");
920   assert(none_of(Ops,
921                  [](uint64_t Op) {
922                    return Op == dwarf::DW_OP_stack_value ||
923                           Op == dwarf::DW_OP_LLVM_fragment;
924                  }) &&
925          "Can't append this op");
926 
927   // Append a DW_OP_deref after Expr's current op list if it's non-empty and
928   // has no DW_OP_stack_value.
929   //
930   // Match .* DW_OP_stack_value (DW_OP_LLVM_fragment A B)?.
931   Optional<FragmentInfo> FI = Expr->getFragmentInfo();
932   unsigned DropUntilStackValue = FI.hasValue() ? 3 : 0;
933   ArrayRef<uint64_t> ExprOpsBeforeFragment =
934       Expr->getElements().drop_back(DropUntilStackValue);
935   bool NeedsDeref = (Expr->getNumElements() > DropUntilStackValue) &&
936                     (ExprOpsBeforeFragment.back() != dwarf::DW_OP_stack_value);
937   bool NeedsStackValue = NeedsDeref || ExprOpsBeforeFragment.empty();
938 
939   // Append a DW_OP_deref after Expr's current op list if needed, then append
940   // the new ops, and finally ensure that a single DW_OP_stack_value is present.
941   SmallVector<uint64_t, 16> NewOps;
942   if (NeedsDeref)
943     NewOps.push_back(dwarf::DW_OP_deref);
944   NewOps.append(Ops.begin(), Ops.end());
945   if (NeedsStackValue)
946     NewOps.push_back(dwarf::DW_OP_stack_value);
947   return DIExpression::append(Expr, NewOps);
948 }
949 
950 Optional<DIExpression *> DIExpression::createFragmentExpression(
951     const DIExpression *Expr, unsigned OffsetInBits, unsigned SizeInBits) {
952   SmallVector<uint64_t, 8> Ops;
953   // Copy over the expression, but leave off any trailing DW_OP_LLVM_fragment.
954   if (Expr) {
955     for (auto Op : Expr->expr_ops()) {
956       switch (Op.getOp()) {
957       default: break;
958       case dwarf::DW_OP_plus:
959       case dwarf::DW_OP_minus:
960         // We can't safely split arithmetic into multiple fragments because we
961         // can't express carry-over between fragments.
962         //
963         // FIXME: We *could* preserve the lowest fragment of a constant offset
964         // operation if the offset fits into SizeInBits.
965         return None;
966       case dwarf::DW_OP_LLVM_fragment: {
967         // Make the new offset point into the existing fragment.
968         uint64_t FragmentOffsetInBits = Op.getArg(0);
969         uint64_t FragmentSizeInBits = Op.getArg(1);
970         (void)FragmentSizeInBits;
971         assert((OffsetInBits + SizeInBits <= FragmentSizeInBits) &&
972                "new fragment outside of original fragment");
973         OffsetInBits += FragmentOffsetInBits;
974         continue;
975       }
976       }
977       Op.appendToVector(Ops);
978     }
979   }
980   Ops.push_back(dwarf::DW_OP_LLVM_fragment);
981   Ops.push_back(OffsetInBits);
982   Ops.push_back(SizeInBits);
983   return DIExpression::get(Expr->getContext(), Ops);
984 }
985 
986 bool DIExpression::isConstant() const {
987   // Recognize DW_OP_constu C DW_OP_stack_value (DW_OP_LLVM_fragment Len Ofs)?.
988   if (getNumElements() != 3 && getNumElements() != 6)
989     return false;
990   if (getElement(0) != dwarf::DW_OP_constu ||
991       getElement(2) != dwarf::DW_OP_stack_value)
992     return false;
993   if (getNumElements() == 6 && getElement(3) != dwarf::DW_OP_LLVM_fragment)
994     return false;
995   return true;
996 }
997 
998 DIGlobalVariableExpression *
999 DIGlobalVariableExpression::getImpl(LLVMContext &Context, Metadata *Variable,
1000                                     Metadata *Expression, StorageType Storage,
1001                                     bool ShouldCreate) {
1002   DEFINE_GETIMPL_LOOKUP(DIGlobalVariableExpression, (Variable, Expression));
1003   Metadata *Ops[] = {Variable, Expression};
1004   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIGlobalVariableExpression, Ops);
1005 }
1006 
1007 DIObjCProperty *DIObjCProperty::getImpl(
1008     LLVMContext &Context, MDString *Name, Metadata *File, unsigned Line,
1009     MDString *GetterName, MDString *SetterName, unsigned Attributes,
1010     Metadata *Type, StorageType Storage, bool ShouldCreate) {
1011   assert(isCanonical(Name) && "Expected canonical MDString");
1012   assert(isCanonical(GetterName) && "Expected canonical MDString");
1013   assert(isCanonical(SetterName) && "Expected canonical MDString");
1014   DEFINE_GETIMPL_LOOKUP(DIObjCProperty, (Name, File, Line, GetterName,
1015                                          SetterName, Attributes, Type));
1016   Metadata *Ops[] = {Name, File, GetterName, SetterName, Type};
1017   DEFINE_GETIMPL_STORE(DIObjCProperty, (Line, Attributes), Ops);
1018 }
1019 
1020 DIImportedEntity *DIImportedEntity::getImpl(LLVMContext &Context, unsigned Tag,
1021                                             Metadata *Scope, Metadata *Entity,
1022                                             Metadata *File, unsigned Line,
1023                                             MDString *Name, StorageType Storage,
1024                                             bool ShouldCreate) {
1025   assert(isCanonical(Name) && "Expected canonical MDString");
1026   DEFINE_GETIMPL_LOOKUP(DIImportedEntity,
1027                         (Tag, Scope, Entity, File, Line, Name));
1028   Metadata *Ops[] = {Scope, Entity, Name, File};
1029   DEFINE_GETIMPL_STORE(DIImportedEntity, (Tag, Line), Ops);
1030 }
1031 
1032 DIMacro *DIMacro::getImpl(LLVMContext &Context, unsigned MIType,
1033                           unsigned Line, MDString *Name, MDString *Value,
1034                           StorageType Storage, bool ShouldCreate) {
1035   assert(isCanonical(Name) && "Expected canonical MDString");
1036   DEFINE_GETIMPL_LOOKUP(DIMacro, (MIType, Line, Name, Value));
1037   Metadata *Ops[] = { Name, Value };
1038   DEFINE_GETIMPL_STORE(DIMacro, (MIType, Line), Ops);
1039 }
1040 
1041 DIMacroFile *DIMacroFile::getImpl(LLVMContext &Context, unsigned MIType,
1042                                   unsigned Line, Metadata *File,
1043                                   Metadata *Elements, StorageType Storage,
1044                                   bool ShouldCreate) {
1045   DEFINE_GETIMPL_LOOKUP(DIMacroFile,
1046                         (MIType, Line, File, Elements));
1047   Metadata *Ops[] = { File, Elements };
1048   DEFINE_GETIMPL_STORE(DIMacroFile, (MIType, Line), Ops);
1049 }
1050