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