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     unsigned ScopeLine, Metadata *ContainingType, unsigned VirtualIndex,
549     int ThisAdjustment, DIFlags Flags, DISPFlags SPFlags, Metadata *Unit,
550     Metadata *TemplateParams, Metadata *Declaration, Metadata *RetainedNodes,
551     Metadata *ThrownTypes, StorageType Storage, bool ShouldCreate) {
552   assert(isCanonical(Name) && "Expected canonical MDString");
553   assert(isCanonical(LinkageName) && "Expected canonical MDString");
554   DEFINE_GETIMPL_LOOKUP(DISubprogram,
555                         (Scope, Name, LinkageName, File, Line, Type, ScopeLine,
556                          ContainingType, VirtualIndex, ThisAdjustment, Flags,
557                          SPFlags, Unit, TemplateParams, Declaration,
558                          RetainedNodes, ThrownTypes));
559   SmallVector<Metadata *, 11> Ops = {
560       File,        Scope,         Name,           LinkageName,    Type,       Unit,
561       Declaration, RetainedNodes, ContainingType, TemplateParams, ThrownTypes};
562   if (!ThrownTypes) {
563     Ops.pop_back();
564     if (!TemplateParams) {
565       Ops.pop_back();
566       if (!ContainingType)
567         Ops.pop_back();
568     }
569   }
570   DEFINE_GETIMPL_STORE_N(
571       DISubprogram,
572       (Line, ScopeLine, VirtualIndex, ThisAdjustment, Flags, SPFlags), Ops,
573       Ops.size());
574 }
575 
576 bool DISubprogram::describes(const Function *F) const {
577   assert(F && "Invalid function");
578   if (F->getSubprogram() == this)
579     return true;
580   StringRef Name = getLinkageName();
581   if (Name.empty())
582     Name = getName();
583   return F->getName() == Name;
584 }
585 
586 DILexicalBlock *DILexicalBlock::getImpl(LLVMContext &Context, Metadata *Scope,
587                                         Metadata *File, unsigned Line,
588                                         unsigned Column, StorageType Storage,
589                                         bool ShouldCreate) {
590   // Fixup column.
591   adjustColumn(Column);
592 
593   assert(Scope && "Expected scope");
594   DEFINE_GETIMPL_LOOKUP(DILexicalBlock, (Scope, File, Line, Column));
595   Metadata *Ops[] = {File, Scope};
596   DEFINE_GETIMPL_STORE(DILexicalBlock, (Line, Column), Ops);
597 }
598 
599 DILexicalBlockFile *DILexicalBlockFile::getImpl(LLVMContext &Context,
600                                                 Metadata *Scope, Metadata *File,
601                                                 unsigned Discriminator,
602                                                 StorageType Storage,
603                                                 bool ShouldCreate) {
604   assert(Scope && "Expected scope");
605   DEFINE_GETIMPL_LOOKUP(DILexicalBlockFile, (Scope, File, Discriminator));
606   Metadata *Ops[] = {File, Scope};
607   DEFINE_GETIMPL_STORE(DILexicalBlockFile, (Discriminator), Ops);
608 }
609 
610 DINamespace *DINamespace::getImpl(LLVMContext &Context, Metadata *Scope,
611                                   MDString *Name, bool ExportSymbols,
612                                   StorageType Storage, bool ShouldCreate) {
613   assert(isCanonical(Name) && "Expected canonical MDString");
614   DEFINE_GETIMPL_LOOKUP(DINamespace, (Scope, Name, ExportSymbols));
615   // The nullptr is for DIScope's File operand. This should be refactored.
616   Metadata *Ops[] = {nullptr, Scope, Name};
617   DEFINE_GETIMPL_STORE(DINamespace, (ExportSymbols), Ops);
618 }
619 
620 DIModule *DIModule::getImpl(LLVMContext &Context, Metadata *Scope,
621                             MDString *Name, MDString *ConfigurationMacros,
622                             MDString *IncludePath, MDString *ISysRoot,
623                             StorageType Storage, bool ShouldCreate) {
624   assert(isCanonical(Name) && "Expected canonical MDString");
625   DEFINE_GETIMPL_LOOKUP(
626       DIModule, (Scope, Name, ConfigurationMacros, IncludePath, ISysRoot));
627   Metadata *Ops[] = {Scope, Name, ConfigurationMacros, IncludePath, ISysRoot};
628   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIModule, Ops);
629 }
630 
631 DITemplateTypeParameter *DITemplateTypeParameter::getImpl(LLVMContext &Context,
632                                                           MDString *Name,
633                                                           Metadata *Type,
634                                                           StorageType Storage,
635                                                           bool ShouldCreate) {
636   assert(isCanonical(Name) && "Expected canonical MDString");
637   DEFINE_GETIMPL_LOOKUP(DITemplateTypeParameter, (Name, Type));
638   Metadata *Ops[] = {Name, Type};
639   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DITemplateTypeParameter, Ops);
640 }
641 
642 DITemplateValueParameter *DITemplateValueParameter::getImpl(
643     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *Type,
644     Metadata *Value, StorageType Storage, bool ShouldCreate) {
645   assert(isCanonical(Name) && "Expected canonical MDString");
646   DEFINE_GETIMPL_LOOKUP(DITemplateValueParameter, (Tag, Name, Type, Value));
647   Metadata *Ops[] = {Name, Type, Value};
648   DEFINE_GETIMPL_STORE(DITemplateValueParameter, (Tag), Ops);
649 }
650 
651 DIGlobalVariable *
652 DIGlobalVariable::getImpl(LLVMContext &Context, Metadata *Scope, MDString *Name,
653                           MDString *LinkageName, Metadata *File, unsigned Line,
654                           Metadata *Type, bool IsLocalToUnit, bool IsDefinition,
655                           Metadata *StaticDataMemberDeclaration,
656                           Metadata *TemplateParams, uint32_t AlignInBits,
657                           StorageType Storage, bool ShouldCreate) {
658   assert(isCanonical(Name) && "Expected canonical MDString");
659   assert(isCanonical(LinkageName) && "Expected canonical MDString");
660   DEFINE_GETIMPL_LOOKUP(DIGlobalVariable, (Scope, Name, LinkageName, File, Line,
661                                            Type, IsLocalToUnit, IsDefinition,
662                                            StaticDataMemberDeclaration,
663                                            TemplateParams, AlignInBits));
664   Metadata *Ops[] = {Scope,
665                      Name,
666                      File,
667                      Type,
668                      Name,
669                      LinkageName,
670                      StaticDataMemberDeclaration,
671                      TemplateParams};
672   DEFINE_GETIMPL_STORE(DIGlobalVariable,
673                        (Line, IsLocalToUnit, IsDefinition, AlignInBits), Ops);
674 }
675 
676 DILocalVariable *DILocalVariable::getImpl(LLVMContext &Context, Metadata *Scope,
677                                           MDString *Name, Metadata *File,
678                                           unsigned Line, Metadata *Type,
679                                           unsigned Arg, DIFlags Flags,
680                                           uint32_t AlignInBits,
681                                           StorageType Storage,
682                                           bool ShouldCreate) {
683   // 64K ought to be enough for any frontend.
684   assert(Arg <= UINT16_MAX && "Expected argument number to fit in 16-bits");
685 
686   assert(Scope && "Expected scope");
687   assert(isCanonical(Name) && "Expected canonical MDString");
688   DEFINE_GETIMPL_LOOKUP(DILocalVariable,
689                         (Scope, Name, File, Line, Type, Arg, Flags,
690                          AlignInBits));
691   Metadata *Ops[] = {Scope, Name, File, Type};
692   DEFINE_GETIMPL_STORE(DILocalVariable, (Line, Arg, Flags, AlignInBits), Ops);
693 }
694 
695 Optional<uint64_t> DIVariable::getSizeInBits() const {
696   // This is used by the Verifier so be mindful of broken types.
697   const Metadata *RawType = getRawType();
698   while (RawType) {
699     // Try to get the size directly.
700     if (auto *T = dyn_cast<DIType>(RawType))
701       if (uint64_t Size = T->getSizeInBits())
702         return Size;
703 
704     if (auto *DT = dyn_cast<DIDerivedType>(RawType)) {
705       // Look at the base type.
706       RawType = DT->getRawBaseType();
707       continue;
708     }
709 
710     // Missing type or size.
711     break;
712   }
713 
714   // Fail gracefully.
715   return None;
716 }
717 
718 DILabel *DILabel::getImpl(LLVMContext &Context, Metadata *Scope,
719                           MDString *Name, Metadata *File, unsigned Line,
720                           StorageType Storage,
721                           bool ShouldCreate) {
722   assert(Scope && "Expected scope");
723   assert(isCanonical(Name) && "Expected canonical MDString");
724   DEFINE_GETIMPL_LOOKUP(DILabel,
725                         (Scope, Name, File, Line));
726   Metadata *Ops[] = {Scope, Name, File};
727   DEFINE_GETIMPL_STORE(DILabel, (Line), Ops);
728 }
729 
730 DIExpression *DIExpression::getImpl(LLVMContext &Context,
731                                     ArrayRef<uint64_t> Elements,
732                                     StorageType Storage, bool ShouldCreate) {
733   DEFINE_GETIMPL_LOOKUP(DIExpression, (Elements));
734   DEFINE_GETIMPL_STORE_NO_OPS(DIExpression, (Elements));
735 }
736 
737 unsigned DIExpression::ExprOperand::getSize() const {
738   switch (getOp()) {
739   case dwarf::DW_OP_LLVM_fragment:
740     return 3;
741   case dwarf::DW_OP_constu:
742   case dwarf::DW_OP_plus_uconst:
743     return 2;
744   default:
745     return 1;
746   }
747 }
748 
749 bool DIExpression::isValid() const {
750   for (auto I = expr_op_begin(), E = expr_op_end(); I != E; ++I) {
751     // Check that there's space for the operand.
752     if (I->get() + I->getSize() > E->get())
753       return false;
754 
755     // Check that the operand is valid.
756     switch (I->getOp()) {
757     default:
758       return false;
759     case dwarf::DW_OP_LLVM_fragment:
760       // A fragment operator must appear at the end.
761       return I->get() + I->getSize() == E->get();
762     case dwarf::DW_OP_stack_value: {
763       // Must be the last one or followed by a DW_OP_LLVM_fragment.
764       if (I->get() + I->getSize() == E->get())
765         break;
766       auto J = I;
767       if ((++J)->getOp() != dwarf::DW_OP_LLVM_fragment)
768         return false;
769       break;
770     }
771     case dwarf::DW_OP_swap: {
772       // Must be more than one implicit element on the stack.
773 
774       // FIXME: A better way to implement this would be to add a local variable
775       // that keeps track of the stack depth and introduce something like a
776       // DW_LLVM_OP_implicit_location as a placeholder for the location this
777       // DIExpression is attached to, or else pass the number of implicit stack
778       // elements into isValid.
779       if (getNumElements() == 1)
780         return false;
781       break;
782     }
783     case dwarf::DW_OP_constu:
784     case dwarf::DW_OP_plus_uconst:
785     case dwarf::DW_OP_plus:
786     case dwarf::DW_OP_minus:
787     case dwarf::DW_OP_mul:
788     case dwarf::DW_OP_div:
789     case dwarf::DW_OP_mod:
790     case dwarf::DW_OP_or:
791     case dwarf::DW_OP_and:
792     case dwarf::DW_OP_xor:
793     case dwarf::DW_OP_shl:
794     case dwarf::DW_OP_shr:
795     case dwarf::DW_OP_shra:
796     case dwarf::DW_OP_deref:
797     case dwarf::DW_OP_xderef:
798     case dwarf::DW_OP_lit0:
799     case dwarf::DW_OP_not:
800     case dwarf::DW_OP_dup:
801       break;
802     }
803   }
804   return true;
805 }
806 
807 Optional<DIExpression::FragmentInfo>
808 DIExpression::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) {
809   for (auto I = Start; I != End; ++I)
810     if (I->getOp() == dwarf::DW_OP_LLVM_fragment) {
811       DIExpression::FragmentInfo Info = {I->getArg(1), I->getArg(0)};
812       return Info;
813     }
814   return None;
815 }
816 
817 void DIExpression::appendOffset(SmallVectorImpl<uint64_t> &Ops,
818                                 int64_t Offset) {
819   if (Offset > 0) {
820     Ops.push_back(dwarf::DW_OP_plus_uconst);
821     Ops.push_back(Offset);
822   } else if (Offset < 0) {
823     Ops.push_back(dwarf::DW_OP_constu);
824     Ops.push_back(-Offset);
825     Ops.push_back(dwarf::DW_OP_minus);
826   }
827 }
828 
829 bool DIExpression::extractIfOffset(int64_t &Offset) const {
830   if (getNumElements() == 0) {
831     Offset = 0;
832     return true;
833   }
834 
835   if (getNumElements() == 2 && Elements[0] == dwarf::DW_OP_plus_uconst) {
836     Offset = Elements[1];
837     return true;
838   }
839 
840   if (getNumElements() == 3 && Elements[0] == dwarf::DW_OP_constu) {
841     if (Elements[2] == dwarf::DW_OP_plus) {
842       Offset = Elements[1];
843       return true;
844     }
845     if (Elements[2] == dwarf::DW_OP_minus) {
846       Offset = -Elements[1];
847       return true;
848     }
849   }
850 
851   return false;
852 }
853 
854 DIExpression *DIExpression::prepend(const DIExpression *Expr, bool DerefBefore,
855                                     int64_t Offset, bool DerefAfter,
856                                     bool StackValue) {
857   SmallVector<uint64_t, 8> Ops;
858   if (DerefBefore)
859     Ops.push_back(dwarf::DW_OP_deref);
860 
861   appendOffset(Ops, Offset);
862   if (DerefAfter)
863     Ops.push_back(dwarf::DW_OP_deref);
864 
865   return prependOpcodes(Expr, Ops, StackValue);
866 }
867 
868 DIExpression *DIExpression::prependOpcodes(const DIExpression *Expr,
869                                            SmallVectorImpl<uint64_t> &Ops,
870                                            bool StackValue) {
871   assert(Expr && "Can't prepend ops to this expression");
872 
873   // If there are no ops to prepend, do not even add the DW_OP_stack_value.
874   if (Ops.empty())
875     StackValue = false;
876   for (auto Op : Expr->expr_ops()) {
877     // A DW_OP_stack_value comes at the end, but before a DW_OP_LLVM_fragment.
878     if (StackValue) {
879       if (Op.getOp() == dwarf::DW_OP_stack_value)
880         StackValue = false;
881       else if (Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
882         Ops.push_back(dwarf::DW_OP_stack_value);
883         StackValue = false;
884       }
885     }
886     Op.appendToVector(Ops);
887   }
888   if (StackValue)
889     Ops.push_back(dwarf::DW_OP_stack_value);
890   return DIExpression::get(Expr->getContext(), Ops);
891 }
892 
893 DIExpression *DIExpression::append(const DIExpression *Expr,
894                                    ArrayRef<uint64_t> Ops) {
895   assert(Expr && !Ops.empty() && "Can't append ops to this expression");
896 
897   // Copy Expr's current op list.
898   SmallVector<uint64_t, 16> NewOps;
899   for (auto Op : Expr->expr_ops()) {
900     // Append new opcodes before DW_OP_{stack_value, LLVM_fragment}.
901     if (Op.getOp() == dwarf::DW_OP_stack_value ||
902         Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
903       NewOps.append(Ops.begin(), Ops.end());
904 
905       // Ensure that the new opcodes are only appended once.
906       Ops = None;
907     }
908     Op.appendToVector(NewOps);
909   }
910 
911   NewOps.append(Ops.begin(), Ops.end());
912   return DIExpression::get(Expr->getContext(), NewOps);
913 }
914 
915 DIExpression *DIExpression::appendToStack(const DIExpression *Expr,
916                                           ArrayRef<uint64_t> Ops) {
917   assert(Expr && !Ops.empty() && "Can't append ops to this expression");
918   assert(none_of(Ops,
919                  [](uint64_t Op) {
920                    return Op == dwarf::DW_OP_stack_value ||
921                           Op == dwarf::DW_OP_LLVM_fragment;
922                  }) &&
923          "Can't append this op");
924 
925   // Append a DW_OP_deref after Expr's current op list if it's non-empty and
926   // has no DW_OP_stack_value.
927   //
928   // Match .* DW_OP_stack_value (DW_OP_LLVM_fragment A B)?.
929   Optional<FragmentInfo> FI = Expr->getFragmentInfo();
930   unsigned DropUntilStackValue = FI.hasValue() ? 3 : 0;
931   ArrayRef<uint64_t> ExprOpsBeforeFragment =
932       Expr->getElements().drop_back(DropUntilStackValue);
933   bool NeedsDeref = (Expr->getNumElements() > DropUntilStackValue) &&
934                     (ExprOpsBeforeFragment.back() != dwarf::DW_OP_stack_value);
935   bool NeedsStackValue = NeedsDeref || ExprOpsBeforeFragment.empty();
936 
937   // Append a DW_OP_deref after Expr's current op list if needed, then append
938   // the new ops, and finally ensure that a single DW_OP_stack_value is present.
939   SmallVector<uint64_t, 16> NewOps;
940   if (NeedsDeref)
941     NewOps.push_back(dwarf::DW_OP_deref);
942   NewOps.append(Ops.begin(), Ops.end());
943   if (NeedsStackValue)
944     NewOps.push_back(dwarf::DW_OP_stack_value);
945   return DIExpression::append(Expr, NewOps);
946 }
947 
948 Optional<DIExpression *> DIExpression::createFragmentExpression(
949     const DIExpression *Expr, unsigned OffsetInBits, unsigned SizeInBits) {
950   SmallVector<uint64_t, 8> Ops;
951   // Copy over the expression, but leave off any trailing DW_OP_LLVM_fragment.
952   if (Expr) {
953     for (auto Op : Expr->expr_ops()) {
954       switch (Op.getOp()) {
955       default: break;
956       case dwarf::DW_OP_plus:
957       case dwarf::DW_OP_minus:
958         // We can't safely split arithmetic into multiple fragments because we
959         // can't express carry-over between fragments.
960         //
961         // FIXME: We *could* preserve the lowest fragment of a constant offset
962         // operation if the offset fits into SizeInBits.
963         return None;
964       case dwarf::DW_OP_LLVM_fragment: {
965         // Make the new offset point into the existing fragment.
966         uint64_t FragmentOffsetInBits = Op.getArg(0);
967         uint64_t FragmentSizeInBits = Op.getArg(1);
968         (void)FragmentSizeInBits;
969         assert((OffsetInBits + SizeInBits <= FragmentSizeInBits) &&
970                "new fragment outside of original fragment");
971         OffsetInBits += FragmentOffsetInBits;
972         continue;
973       }
974       }
975       Op.appendToVector(Ops);
976     }
977   }
978   Ops.push_back(dwarf::DW_OP_LLVM_fragment);
979   Ops.push_back(OffsetInBits);
980   Ops.push_back(SizeInBits);
981   return DIExpression::get(Expr->getContext(), Ops);
982 }
983 
984 bool DIExpression::isConstant() const {
985   // Recognize DW_OP_constu C DW_OP_stack_value (DW_OP_LLVM_fragment Len Ofs)?.
986   if (getNumElements() != 3 && getNumElements() != 6)
987     return false;
988   if (getElement(0) != dwarf::DW_OP_constu ||
989       getElement(2) != dwarf::DW_OP_stack_value)
990     return false;
991   if (getNumElements() == 6 && getElement(3) != dwarf::DW_OP_LLVM_fragment)
992     return false;
993   return true;
994 }
995 
996 DIGlobalVariableExpression *
997 DIGlobalVariableExpression::getImpl(LLVMContext &Context, Metadata *Variable,
998                                     Metadata *Expression, StorageType Storage,
999                                     bool ShouldCreate) {
1000   DEFINE_GETIMPL_LOOKUP(DIGlobalVariableExpression, (Variable, Expression));
1001   Metadata *Ops[] = {Variable, Expression};
1002   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIGlobalVariableExpression, Ops);
1003 }
1004 
1005 DIObjCProperty *DIObjCProperty::getImpl(
1006     LLVMContext &Context, MDString *Name, Metadata *File, unsigned Line,
1007     MDString *GetterName, MDString *SetterName, unsigned Attributes,
1008     Metadata *Type, StorageType Storage, bool ShouldCreate) {
1009   assert(isCanonical(Name) && "Expected canonical MDString");
1010   assert(isCanonical(GetterName) && "Expected canonical MDString");
1011   assert(isCanonical(SetterName) && "Expected canonical MDString");
1012   DEFINE_GETIMPL_LOOKUP(DIObjCProperty, (Name, File, Line, GetterName,
1013                                          SetterName, Attributes, Type));
1014   Metadata *Ops[] = {Name, File, GetterName, SetterName, Type};
1015   DEFINE_GETIMPL_STORE(DIObjCProperty, (Line, Attributes), Ops);
1016 }
1017 
1018 DIImportedEntity *DIImportedEntity::getImpl(LLVMContext &Context, unsigned Tag,
1019                                             Metadata *Scope, Metadata *Entity,
1020                                             Metadata *File, unsigned Line,
1021                                             MDString *Name, StorageType Storage,
1022                                             bool ShouldCreate) {
1023   assert(isCanonical(Name) && "Expected canonical MDString");
1024   DEFINE_GETIMPL_LOOKUP(DIImportedEntity,
1025                         (Tag, Scope, Entity, File, Line, Name));
1026   Metadata *Ops[] = {Scope, Entity, Name, File};
1027   DEFINE_GETIMPL_STORE(DIImportedEntity, (Tag, Line), Ops);
1028 }
1029 
1030 DIMacro *DIMacro::getImpl(LLVMContext &Context, unsigned MIType,
1031                           unsigned Line, MDString *Name, MDString *Value,
1032                           StorageType Storage, bool ShouldCreate) {
1033   assert(isCanonical(Name) && "Expected canonical MDString");
1034   DEFINE_GETIMPL_LOOKUP(DIMacro, (MIType, Line, Name, Value));
1035   Metadata *Ops[] = { Name, Value };
1036   DEFINE_GETIMPL_STORE(DIMacro, (MIType, Line), Ops);
1037 }
1038 
1039 DIMacroFile *DIMacroFile::getImpl(LLVMContext &Context, unsigned MIType,
1040                                   unsigned Line, Metadata *File,
1041                                   Metadata *Elements, StorageType Storage,
1042                                   bool ShouldCreate) {
1043   DEFINE_GETIMPL_LOOKUP(DIMacroFile,
1044                         (MIType, Line, File, Elements));
1045   Metadata *Ops[] = { File, Elements };
1046   DEFINE_GETIMPL_STORE(DIMacroFile, (MIType, Line), Ops);
1047 }
1048