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 *
72 DILocation::getMergedLocation(const DILocation *LocA, const DILocation *LocB,
73                               const Instruction *ForInst) {
74   if (!LocA || !LocB)
75     return nullptr;
76 
77   if (LocA == LocB || !LocA->canDiscriminate(*LocB))
78     return LocA;
79 
80   if (!dyn_cast_or_null<CallInst>(ForInst))
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                                   StorageType Storage, bool ShouldCreate) {
278   assert(isCanonical(Name) && "Expected canonical MDString");
279   DEFINE_GETIMPL_LOOKUP(DIBasicType,
280                         (Tag, Name, SizeInBits, AlignInBits, Encoding));
281   Metadata *Ops[] = {nullptr, nullptr, Name};
282   DEFINE_GETIMPL_STORE(DIBasicType, (Tag, SizeInBits, AlignInBits, Encoding),
283                        Ops);
284 }
285 
286 DIDerivedType *DIDerivedType::getImpl(
287     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *File,
288     unsigned Line, Metadata *Scope, Metadata *BaseType, uint64_t SizeInBits,
289     uint32_t AlignInBits, uint64_t OffsetInBits,
290     Optional<unsigned> DWARFAddressSpace, DIFlags Flags, Metadata *ExtraData,
291     StorageType Storage, bool ShouldCreate) {
292   assert(isCanonical(Name) && "Expected canonical MDString");
293   DEFINE_GETIMPL_LOOKUP(DIDerivedType,
294                         (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
295                          AlignInBits, OffsetInBits, DWARFAddressSpace, Flags,
296                          ExtraData));
297   Metadata *Ops[] = {File, Scope, Name, BaseType, ExtraData};
298   DEFINE_GETIMPL_STORE(
299       DIDerivedType, (Tag, Line, SizeInBits, AlignInBits, OffsetInBits,
300                       DWARFAddressSpace, Flags), Ops);
301 }
302 
303 DICompositeType *DICompositeType::getImpl(
304     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *File,
305     unsigned Line, Metadata *Scope, Metadata *BaseType, uint64_t SizeInBits,
306     uint32_t AlignInBits, uint64_t OffsetInBits, DIFlags Flags,
307     Metadata *Elements, unsigned RuntimeLang, Metadata *VTableHolder,
308     Metadata *TemplateParams, MDString *Identifier, Metadata *Discriminator,
309     StorageType Storage, bool ShouldCreate) {
310   assert(isCanonical(Name) && "Expected canonical MDString");
311 
312   // Keep this in sync with buildODRType.
313   DEFINE_GETIMPL_LOOKUP(
314       DICompositeType, (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
315                         AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang,
316                         VTableHolder, TemplateParams, Identifier, Discriminator));
317   Metadata *Ops[] = {File,     Scope,        Name,           BaseType,
318                      Elements, VTableHolder, TemplateParams, Identifier,
319                      Discriminator};
320   DEFINE_GETIMPL_STORE(DICompositeType, (Tag, Line, RuntimeLang, SizeInBits,
321                                          AlignInBits, OffsetInBits, Flags),
322                        Ops);
323 }
324 
325 DICompositeType *DICompositeType::buildODRType(
326     LLVMContext &Context, MDString &Identifier, unsigned Tag, MDString *Name,
327     Metadata *File, unsigned Line, Metadata *Scope, Metadata *BaseType,
328     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
329     DIFlags Flags, Metadata *Elements, unsigned RuntimeLang,
330     Metadata *VTableHolder, Metadata *TemplateParams, Metadata *Discriminator) {
331   assert(!Identifier.getString().empty() && "Expected valid identifier");
332   if (!Context.isODRUniquingDebugTypes())
333     return nullptr;
334   auto *&CT = (*Context.pImpl->DITypeMap)[&Identifier];
335   if (!CT)
336     return CT = DICompositeType::getDistinct(
337                Context, Tag, Name, File, Line, Scope, BaseType, SizeInBits,
338                AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang,
339                VTableHolder, TemplateParams, &Identifier, Discriminator);
340 
341   // Only mutate CT if it's a forward declaration and the new operands aren't.
342   assert(CT->getRawIdentifier() == &Identifier && "Wrong ODR identifier?");
343   if (!CT->isForwardDecl() || (Flags & DINode::FlagFwdDecl))
344     return CT;
345 
346   // Mutate CT in place.  Keep this in sync with getImpl.
347   CT->mutate(Tag, Line, RuntimeLang, SizeInBits, AlignInBits, OffsetInBits,
348              Flags);
349   Metadata *Ops[] = {File,     Scope,        Name,           BaseType,
350                      Elements, VTableHolder, TemplateParams, &Identifier,
351                      Discriminator};
352   assert((std::end(Ops) - std::begin(Ops)) == (int)CT->getNumOperands() &&
353          "Mismatched number of operands");
354   for (unsigned I = 0, E = CT->getNumOperands(); I != E; ++I)
355     if (Ops[I] != CT->getOperand(I))
356       CT->setOperand(I, Ops[I]);
357   return CT;
358 }
359 
360 DICompositeType *DICompositeType::getODRType(
361     LLVMContext &Context, MDString &Identifier, unsigned Tag, MDString *Name,
362     Metadata *File, unsigned Line, Metadata *Scope, Metadata *BaseType,
363     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
364     DIFlags Flags, Metadata *Elements, unsigned RuntimeLang,
365     Metadata *VTableHolder, Metadata *TemplateParams, Metadata *Discriminator) {
366   assert(!Identifier.getString().empty() && "Expected valid identifier");
367   if (!Context.isODRUniquingDebugTypes())
368     return nullptr;
369   auto *&CT = (*Context.pImpl->DITypeMap)[&Identifier];
370   if (!CT)
371     CT = DICompositeType::getDistinct(
372         Context, Tag, Name, File, Line, Scope, BaseType, SizeInBits,
373         AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang, VTableHolder,
374         TemplateParams, &Identifier, Discriminator);
375   return CT;
376 }
377 
378 DICompositeType *DICompositeType::getODRTypeIfExists(LLVMContext &Context,
379                                                      MDString &Identifier) {
380   assert(!Identifier.getString().empty() && "Expected valid identifier");
381   if (!Context.isODRUniquingDebugTypes())
382     return nullptr;
383   return Context.pImpl->DITypeMap->lookup(&Identifier);
384 }
385 
386 DISubroutineType *DISubroutineType::getImpl(LLVMContext &Context, DIFlags Flags,
387                                             uint8_t CC, Metadata *TypeArray,
388                                             StorageType Storage,
389                                             bool ShouldCreate) {
390   DEFINE_GETIMPL_LOOKUP(DISubroutineType, (Flags, CC, TypeArray));
391   Metadata *Ops[] = {nullptr, nullptr, nullptr, TypeArray};
392   DEFINE_GETIMPL_STORE(DISubroutineType, (Flags, CC), Ops);
393 }
394 
395 // FIXME: Implement this string-enum correspondence with a .def file and macros,
396 // so that the association is explicit rather than implied.
397 static const char *ChecksumKindName[DIFile::CSK_Last] = {
398   "CSK_MD5",
399   "CSK_SHA1"
400 };
401 
402 StringRef DIFile::getChecksumKindAsString(ChecksumKind CSKind) {
403   assert(CSKind <= DIFile::CSK_Last && "Invalid checksum kind");
404   // The first space was originally the CSK_None variant, which is now
405   // obsolete, but the space is still reserved in ChecksumKind, so we account
406   // for it here.
407   return ChecksumKindName[CSKind - 1];
408 }
409 
410 Optional<DIFile::ChecksumKind> DIFile::getChecksumKind(StringRef CSKindStr) {
411   return StringSwitch<Optional<DIFile::ChecksumKind>>(CSKindStr)
412       .Case("CSK_MD5", DIFile::CSK_MD5)
413       .Case("CSK_SHA1", DIFile::CSK_SHA1)
414       .Default(None);
415 }
416 
417 DIFile *DIFile::getImpl(LLVMContext &Context, MDString *Filename,
418                         MDString *Directory,
419                         Optional<DIFile::ChecksumInfo<MDString *>> CS,
420                         StorageType Storage, bool ShouldCreate) {
421   assert(isCanonical(Filename) && "Expected canonical MDString");
422   assert(isCanonical(Directory) && "Expected canonical MDString");
423   assert((!CS || isCanonical(CS->Value)) && "Expected canonical MDString");
424   DEFINE_GETIMPL_LOOKUP(DIFile, (Filename, Directory, CS));
425   Metadata *Ops[] = {Filename, Directory, CS ? CS->Value : nullptr};
426   DEFINE_GETIMPL_STORE(DIFile, (CS), Ops);
427 }
428 
429 DICompileUnit *DICompileUnit::getImpl(
430     LLVMContext &Context, unsigned SourceLanguage, Metadata *File,
431     MDString *Producer, bool IsOptimized, MDString *Flags,
432     unsigned RuntimeVersion, MDString *SplitDebugFilename,
433     unsigned EmissionKind, Metadata *EnumTypes, Metadata *RetainedTypes,
434     Metadata *GlobalVariables, Metadata *ImportedEntities, Metadata *Macros,
435     uint64_t DWOId, bool SplitDebugInlining, bool DebugInfoForProfiling,
436     bool GnuPubnames, StorageType Storage, bool ShouldCreate) {
437   assert(Storage != Uniqued && "Cannot unique DICompileUnit");
438   assert(isCanonical(Producer) && "Expected canonical MDString");
439   assert(isCanonical(Flags) && "Expected canonical MDString");
440   assert(isCanonical(SplitDebugFilename) && "Expected canonical MDString");
441 
442   Metadata *Ops[] = {
443       File,      Producer,      Flags,           SplitDebugFilename,
444       EnumTypes, RetainedTypes, GlobalVariables, ImportedEntities,
445       Macros};
446   return storeImpl(new (array_lengthof(Ops)) DICompileUnit(
447                        Context, Storage, SourceLanguage, IsOptimized,
448                        RuntimeVersion, EmissionKind, DWOId, SplitDebugInlining,
449                        DebugInfoForProfiling, GnuPubnames, Ops),
450                    Storage);
451 }
452 
453 Optional<DICompileUnit::DebugEmissionKind>
454 DICompileUnit::getEmissionKind(StringRef Str) {
455   return StringSwitch<Optional<DebugEmissionKind>>(Str)
456       .Case("NoDebug", NoDebug)
457       .Case("FullDebug", FullDebug)
458       .Case("LineTablesOnly", LineTablesOnly)
459       .Default(None);
460 }
461 
462 const char *DICompileUnit::EmissionKindString(DebugEmissionKind EK) {
463   switch (EK) {
464   case NoDebug:        return "NoDebug";
465   case FullDebug:      return "FullDebug";
466   case LineTablesOnly: return "LineTablesOnly";
467   }
468   return nullptr;
469 }
470 
471 DISubprogram *DILocalScope::getSubprogram() const {
472   if (auto *Block = dyn_cast<DILexicalBlockBase>(this))
473     return Block->getScope()->getSubprogram();
474   return const_cast<DISubprogram *>(cast<DISubprogram>(this));
475 }
476 
477 DILocalScope *DILocalScope::getNonLexicalBlockFileScope() const {
478   if (auto *File = dyn_cast<DILexicalBlockFile>(this))
479     return File->getScope()->getNonLexicalBlockFileScope();
480   return const_cast<DILocalScope *>(this);
481 }
482 
483 DISubprogram *DISubprogram::getImpl(
484     LLVMContext &Context, Metadata *Scope, MDString *Name,
485     MDString *LinkageName, Metadata *File, unsigned Line, Metadata *Type,
486     bool IsLocalToUnit, bool IsDefinition, unsigned ScopeLine,
487     Metadata *ContainingType, unsigned Virtuality, unsigned VirtualIndex,
488     int ThisAdjustment, DIFlags Flags, bool IsOptimized, Metadata *Unit,
489     Metadata *TemplateParams, Metadata *Declaration, Metadata *Variables,
490     Metadata *ThrownTypes, StorageType Storage, bool ShouldCreate) {
491   assert(isCanonical(Name) && "Expected canonical MDString");
492   assert(isCanonical(LinkageName) && "Expected canonical MDString");
493   DEFINE_GETIMPL_LOOKUP(
494       DISubprogram, (Scope, Name, LinkageName, File, Line, Type, IsLocalToUnit,
495                      IsDefinition, ScopeLine, ContainingType, Virtuality,
496                      VirtualIndex, ThisAdjustment, Flags, IsOptimized, Unit,
497                      TemplateParams, Declaration, Variables, ThrownTypes));
498   SmallVector<Metadata *, 11> Ops = {
499       File,        Scope,     Name,           LinkageName,    Type,       Unit,
500       Declaration, Variables, ContainingType, TemplateParams, ThrownTypes};
501   if (!ThrownTypes) {
502     Ops.pop_back();
503     if (!TemplateParams) {
504       Ops.pop_back();
505       if (!ContainingType)
506         Ops.pop_back();
507     }
508   }
509   DEFINE_GETIMPL_STORE_N(DISubprogram,
510                          (Line, ScopeLine, Virtuality, VirtualIndex,
511                           ThisAdjustment, Flags, IsLocalToUnit, IsDefinition,
512                           IsOptimized),
513                          Ops, Ops.size());
514 }
515 
516 bool DISubprogram::describes(const Function *F) const {
517   assert(F && "Invalid function");
518   if (F->getSubprogram() == this)
519     return true;
520   StringRef Name = getLinkageName();
521   if (Name.empty())
522     Name = getName();
523   return F->getName() == Name;
524 }
525 
526 DILexicalBlock *DILexicalBlock::getImpl(LLVMContext &Context, Metadata *Scope,
527                                         Metadata *File, unsigned Line,
528                                         unsigned Column, StorageType Storage,
529                                         bool ShouldCreate) {
530   // Fixup column.
531   adjustColumn(Column);
532 
533   assert(Scope && "Expected scope");
534   DEFINE_GETIMPL_LOOKUP(DILexicalBlock, (Scope, File, Line, Column));
535   Metadata *Ops[] = {File, Scope};
536   DEFINE_GETIMPL_STORE(DILexicalBlock, (Line, Column), Ops);
537 }
538 
539 DILexicalBlockFile *DILexicalBlockFile::getImpl(LLVMContext &Context,
540                                                 Metadata *Scope, Metadata *File,
541                                                 unsigned Discriminator,
542                                                 StorageType Storage,
543                                                 bool ShouldCreate) {
544   assert(Scope && "Expected scope");
545   DEFINE_GETIMPL_LOOKUP(DILexicalBlockFile, (Scope, File, Discriminator));
546   Metadata *Ops[] = {File, Scope};
547   DEFINE_GETIMPL_STORE(DILexicalBlockFile, (Discriminator), Ops);
548 }
549 
550 DINamespace *DINamespace::getImpl(LLVMContext &Context, Metadata *Scope,
551                                   MDString *Name, bool ExportSymbols,
552                                   StorageType Storage, bool ShouldCreate) {
553   assert(isCanonical(Name) && "Expected canonical MDString");
554   DEFINE_GETIMPL_LOOKUP(DINamespace, (Scope, Name, ExportSymbols));
555   // The nullptr is for DIScope's File operand. This should be refactored.
556   Metadata *Ops[] = {nullptr, Scope, Name};
557   DEFINE_GETIMPL_STORE(DINamespace, (ExportSymbols), Ops);
558 }
559 
560 DIModule *DIModule::getImpl(LLVMContext &Context, Metadata *Scope,
561                             MDString *Name, MDString *ConfigurationMacros,
562                             MDString *IncludePath, MDString *ISysRoot,
563                             StorageType Storage, bool ShouldCreate) {
564   assert(isCanonical(Name) && "Expected canonical MDString");
565   DEFINE_GETIMPL_LOOKUP(
566       DIModule, (Scope, Name, ConfigurationMacros, IncludePath, ISysRoot));
567   Metadata *Ops[] = {Scope, Name, ConfigurationMacros, IncludePath, ISysRoot};
568   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIModule, Ops);
569 }
570 
571 DITemplateTypeParameter *DITemplateTypeParameter::getImpl(LLVMContext &Context,
572                                                           MDString *Name,
573                                                           Metadata *Type,
574                                                           StorageType Storage,
575                                                           bool ShouldCreate) {
576   assert(isCanonical(Name) && "Expected canonical MDString");
577   DEFINE_GETIMPL_LOOKUP(DITemplateTypeParameter, (Name, Type));
578   Metadata *Ops[] = {Name, Type};
579   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DITemplateTypeParameter, Ops);
580 }
581 
582 DITemplateValueParameter *DITemplateValueParameter::getImpl(
583     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *Type,
584     Metadata *Value, StorageType Storage, bool ShouldCreate) {
585   assert(isCanonical(Name) && "Expected canonical MDString");
586   DEFINE_GETIMPL_LOOKUP(DITemplateValueParameter, (Tag, Name, Type, Value));
587   Metadata *Ops[] = {Name, Type, Value};
588   DEFINE_GETIMPL_STORE(DITemplateValueParameter, (Tag), Ops);
589 }
590 
591 DIGlobalVariable *
592 DIGlobalVariable::getImpl(LLVMContext &Context, Metadata *Scope, MDString *Name,
593                           MDString *LinkageName, Metadata *File, unsigned Line,
594                           Metadata *Type, bool IsLocalToUnit, bool IsDefinition,
595                           Metadata *StaticDataMemberDeclaration,
596                           uint32_t AlignInBits, StorageType Storage,
597                           bool ShouldCreate) {
598   assert(isCanonical(Name) && "Expected canonical MDString");
599   assert(isCanonical(LinkageName) && "Expected canonical MDString");
600   DEFINE_GETIMPL_LOOKUP(DIGlobalVariable,
601                         (Scope, Name, LinkageName, File, Line, Type,
602                          IsLocalToUnit, IsDefinition,
603                          StaticDataMemberDeclaration, AlignInBits));
604   Metadata *Ops[] = {
605       Scope, Name, File, Type, Name, LinkageName, StaticDataMemberDeclaration};
606   DEFINE_GETIMPL_STORE(DIGlobalVariable,
607                        (Line, IsLocalToUnit, IsDefinition, AlignInBits),
608                        Ops);
609 }
610 
611 DILocalVariable *DILocalVariable::getImpl(LLVMContext &Context, Metadata *Scope,
612                                           MDString *Name, Metadata *File,
613                                           unsigned Line, Metadata *Type,
614                                           unsigned Arg, DIFlags Flags,
615                                           uint32_t AlignInBits,
616                                           StorageType Storage,
617                                           bool ShouldCreate) {
618   // 64K ought to be enough for any frontend.
619   assert(Arg <= UINT16_MAX && "Expected argument number to fit in 16-bits");
620 
621   assert(Scope && "Expected scope");
622   assert(isCanonical(Name) && "Expected canonical MDString");
623   DEFINE_GETIMPL_LOOKUP(DILocalVariable,
624                         (Scope, Name, File, Line, Type, Arg, Flags,
625                          AlignInBits));
626   Metadata *Ops[] = {Scope, Name, File, Type};
627   DEFINE_GETIMPL_STORE(DILocalVariable, (Line, Arg, Flags, AlignInBits), Ops);
628 }
629 
630 Optional<uint64_t> DIVariable::getSizeInBits() const {
631   // This is used by the Verifier so be mindful of broken types.
632   const Metadata *RawType = getRawType();
633   while (RawType) {
634     // Try to get the size directly.
635     if (auto *T = dyn_cast<DIType>(RawType))
636       if (uint64_t Size = T->getSizeInBits())
637         return Size;
638 
639     if (auto *DT = dyn_cast<DIDerivedType>(RawType)) {
640       // Look at the base type.
641       RawType = DT->getRawBaseType();
642       continue;
643     }
644 
645     // Missing type or size.
646     break;
647   }
648 
649   // Fail gracefully.
650   return None;
651 }
652 
653 DIExpression *DIExpression::getImpl(LLVMContext &Context,
654                                     ArrayRef<uint64_t> Elements,
655                                     StorageType Storage, bool ShouldCreate) {
656   DEFINE_GETIMPL_LOOKUP(DIExpression, (Elements));
657   DEFINE_GETIMPL_STORE_NO_OPS(DIExpression, (Elements));
658 }
659 
660 unsigned DIExpression::ExprOperand::getSize() const {
661   switch (getOp()) {
662   case dwarf::DW_OP_LLVM_fragment:
663     return 3;
664   case dwarf::DW_OP_constu:
665   case dwarf::DW_OP_plus_uconst:
666     return 2;
667   default:
668     return 1;
669   }
670 }
671 
672 bool DIExpression::isValid() const {
673   for (auto I = expr_op_begin(), E = expr_op_end(); I != E; ++I) {
674     // Check that there's space for the operand.
675     if (I->get() + I->getSize() > E->get())
676       return false;
677 
678     // Check that the operand is valid.
679     switch (I->getOp()) {
680     default:
681       return false;
682     case dwarf::DW_OP_LLVM_fragment:
683       // A fragment operator must appear at the end.
684       return I->get() + I->getSize() == E->get();
685     case dwarf::DW_OP_stack_value: {
686       // Must be the last one or followed by a DW_OP_LLVM_fragment.
687       if (I->get() + I->getSize() == E->get())
688         break;
689       auto J = I;
690       if ((++J)->getOp() != dwarf::DW_OP_LLVM_fragment)
691         return false;
692       break;
693     }
694     case dwarf::DW_OP_swap: {
695       // Must be more than one implicit element on the stack.
696 
697       // FIXME: A better way to implement this would be to add a local variable
698       // that keeps track of the stack depth and introduce something like a
699       // DW_LLVM_OP_implicit_location as a placeholder for the location this
700       // DIExpression is attached to, or else pass the number of implicit stack
701       // elements into isValid.
702       if (getNumElements() == 1)
703         return false;
704       break;
705     }
706     case dwarf::DW_OP_constu:
707     case dwarf::DW_OP_plus_uconst:
708     case dwarf::DW_OP_plus:
709     case dwarf::DW_OP_minus:
710     case dwarf::DW_OP_mul:
711     case dwarf::DW_OP_div:
712     case dwarf::DW_OP_mod:
713     case dwarf::DW_OP_or:
714     case dwarf::DW_OP_xor:
715     case dwarf::DW_OP_shl:
716     case dwarf::DW_OP_shr:
717     case dwarf::DW_OP_shra:
718     case dwarf::DW_OP_deref:
719     case dwarf::DW_OP_xderef:
720       break;
721     }
722   }
723   return true;
724 }
725 
726 Optional<DIExpression::FragmentInfo>
727 DIExpression::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) {
728   for (auto I = Start; I != End; ++I)
729     if (I->getOp() == dwarf::DW_OP_LLVM_fragment) {
730       DIExpression::FragmentInfo Info = {I->getArg(1), I->getArg(0)};
731       return Info;
732     }
733   return None;
734 }
735 
736 void DIExpression::appendOffset(SmallVectorImpl<uint64_t> &Ops,
737                                 int64_t Offset) {
738   if (Offset > 0) {
739     Ops.push_back(dwarf::DW_OP_plus_uconst);
740     Ops.push_back(Offset);
741   } else if (Offset < 0) {
742     Ops.push_back(dwarf::DW_OP_constu);
743     Ops.push_back(-Offset);
744     Ops.push_back(dwarf::DW_OP_minus);
745   }
746 }
747 
748 bool DIExpression::extractIfOffset(int64_t &Offset) const {
749   if (getNumElements() == 0) {
750     Offset = 0;
751     return true;
752   }
753 
754   if (getNumElements() == 2 && Elements[0] == dwarf::DW_OP_plus_uconst) {
755     Offset = Elements[1];
756     return true;
757   }
758 
759   if (getNumElements() == 3 && Elements[0] == dwarf::DW_OP_constu) {
760     if (Elements[2] == dwarf::DW_OP_plus) {
761       Offset = Elements[1];
762       return true;
763     }
764     if (Elements[2] == dwarf::DW_OP_minus) {
765       Offset = -Elements[1];
766       return true;
767     }
768   }
769 
770   return false;
771 }
772 
773 DIExpression *DIExpression::prepend(const DIExpression *Expr, bool DerefBefore,
774                                     int64_t Offset, bool DerefAfter,
775                                     bool StackValue) {
776   SmallVector<uint64_t, 8> Ops;
777   if (DerefBefore)
778     Ops.push_back(dwarf::DW_OP_deref);
779 
780   appendOffset(Ops, Offset);
781   if (DerefAfter)
782     Ops.push_back(dwarf::DW_OP_deref);
783 
784   return doPrepend(Expr, Ops, StackValue);
785 }
786 
787 DIExpression *DIExpression::doPrepend(const DIExpression *Expr,
788                                       SmallVectorImpl<uint64_t> &Ops,
789                                       bool StackValue) {
790   if (Expr)
791     for (auto Op : Expr->expr_ops()) {
792       // A DW_OP_stack_value comes at the end, but before a DW_OP_LLVM_fragment.
793       if (StackValue) {
794         if (Op.getOp() == dwarf::DW_OP_stack_value)
795           StackValue = false;
796         else if (Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
797           Ops.push_back(dwarf::DW_OP_stack_value);
798           StackValue = false;
799         }
800       }
801       Ops.push_back(Op.getOp());
802       for (unsigned I = 0; I < Op.getNumArgs(); ++I)
803         Ops.push_back(Op.getArg(I));
804     }
805   if (StackValue)
806     Ops.push_back(dwarf::DW_OP_stack_value);
807   return DIExpression::get(Expr->getContext(), Ops);
808 }
809 
810 Optional<DIExpression *> DIExpression::createFragmentExpression(
811     const DIExpression *Expr, unsigned OffsetInBits, unsigned SizeInBits) {
812   SmallVector<uint64_t, 8> Ops;
813   // Copy over the expression, but leave off any trailing DW_OP_LLVM_fragment.
814   if (Expr) {
815     for (auto Op : Expr->expr_ops()) {
816       switch (Op.getOp()) {
817       default: break;
818       case dwarf::DW_OP_plus:
819       case dwarf::DW_OP_minus:
820         // We can't safely split arithmetic into multiple fragments because we
821         // can't express carry-over between fragments.
822         //
823         // FIXME: We *could* preserve the lowest fragment of a constant offset
824         // operation if the offset fits into SizeInBits.
825         return None;
826       case dwarf::DW_OP_LLVM_fragment: {
827         // Make the new offset point into the existing fragment.
828         uint64_t FragmentOffsetInBits = Op.getArg(0);
829         // Op.getArg(0) is FragmentOffsetInBits.
830         // Op.getArg(1) is FragmentSizeInBits.
831         assert((OffsetInBits + SizeInBits <= Op.getArg(0) + Op.getArg(1)) &&
832                "new fragment outside of original fragment");
833         OffsetInBits += FragmentOffsetInBits;
834         continue;
835       }
836       }
837       Ops.push_back(Op.getOp());
838       for (unsigned I = 0; I < Op.getNumArgs(); ++I)
839         Ops.push_back(Op.getArg(I));
840     }
841   }
842   Ops.push_back(dwarf::DW_OP_LLVM_fragment);
843   Ops.push_back(OffsetInBits);
844   Ops.push_back(SizeInBits);
845   return DIExpression::get(Expr->getContext(), Ops);
846 }
847 
848 bool DIExpression::isConstant() const {
849   // Recognize DW_OP_constu C DW_OP_stack_value (DW_OP_LLVM_fragment Len Ofs)?.
850   if (getNumElements() != 3 && getNumElements() != 6)
851     return false;
852   if (getElement(0) != dwarf::DW_OP_constu ||
853       getElement(2) != dwarf::DW_OP_stack_value)
854     return false;
855   if (getNumElements() == 6 && getElement(3) != dwarf::DW_OP_LLVM_fragment)
856     return false;
857   return true;
858 }
859 
860 DIGlobalVariableExpression *
861 DIGlobalVariableExpression::getImpl(LLVMContext &Context, Metadata *Variable,
862                                     Metadata *Expression, StorageType Storage,
863                                     bool ShouldCreate) {
864   DEFINE_GETIMPL_LOOKUP(DIGlobalVariableExpression, (Variable, Expression));
865   Metadata *Ops[] = {Variable, Expression};
866   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIGlobalVariableExpression, Ops);
867 }
868 
869 DIObjCProperty *DIObjCProperty::getImpl(
870     LLVMContext &Context, MDString *Name, Metadata *File, unsigned Line,
871     MDString *GetterName, MDString *SetterName, unsigned Attributes,
872     Metadata *Type, StorageType Storage, bool ShouldCreate) {
873   assert(isCanonical(Name) && "Expected canonical MDString");
874   assert(isCanonical(GetterName) && "Expected canonical MDString");
875   assert(isCanonical(SetterName) && "Expected canonical MDString");
876   DEFINE_GETIMPL_LOOKUP(DIObjCProperty, (Name, File, Line, GetterName,
877                                          SetterName, Attributes, Type));
878   Metadata *Ops[] = {Name, File, GetterName, SetterName, Type};
879   DEFINE_GETIMPL_STORE(DIObjCProperty, (Line, Attributes), Ops);
880 }
881 
882 DIImportedEntity *DIImportedEntity::getImpl(LLVMContext &Context, unsigned Tag,
883                                             Metadata *Scope, Metadata *Entity,
884                                             Metadata *File, unsigned Line,
885                                             MDString *Name, StorageType Storage,
886                                             bool ShouldCreate) {
887   assert(isCanonical(Name) && "Expected canonical MDString");
888   DEFINE_GETIMPL_LOOKUP(DIImportedEntity,
889                         (Tag, Scope, Entity, File, Line, Name));
890   Metadata *Ops[] = {Scope, Entity, Name, File};
891   DEFINE_GETIMPL_STORE(DIImportedEntity, (Tag, Line), Ops);
892 }
893 
894 DIMacro *DIMacro::getImpl(LLVMContext &Context, unsigned MIType,
895                           unsigned Line, MDString *Name, MDString *Value,
896                           StorageType Storage, bool ShouldCreate) {
897   assert(isCanonical(Name) && "Expected canonical MDString");
898   DEFINE_GETIMPL_LOOKUP(DIMacro, (MIType, Line, Name, Value));
899   Metadata *Ops[] = { Name, Value };
900   DEFINE_GETIMPL_STORE(DIMacro, (MIType, Line), Ops);
901 }
902 
903 DIMacroFile *DIMacroFile::getImpl(LLVMContext &Context, unsigned MIType,
904                                   unsigned Line, Metadata *File,
905                                   Metadata *Elements, StorageType Storage,
906                                   bool ShouldCreate) {
907   DEFINE_GETIMPL_LOOKUP(DIMacroFile,
908                         (MIType, Line, File, Elements));
909   Metadata *Ops[] = { File, Elements };
910   DEFINE_GETIMPL_STORE(DIMacroFile, (MIType, Line), Ops);
911 }
912