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                                   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 Optional<DIBasicType::Signedness> DIBasicType::getSignedness() const {
287   switch (getEncoding()) {
288   case dwarf::DW_ATE_signed:
289   case dwarf::DW_ATE_signed_char:
290     return Signedness::Signed;
291   case dwarf::DW_ATE_unsigned:
292   case dwarf::DW_ATE_unsigned_char:
293     return Signedness::Unsigned;
294   default:
295     return None;
296   }
297 }
298 
299 DIDerivedType *DIDerivedType::getImpl(
300     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *File,
301     unsigned Line, Metadata *Scope, Metadata *BaseType, uint64_t SizeInBits,
302     uint32_t AlignInBits, uint64_t OffsetInBits,
303     Optional<unsigned> DWARFAddressSpace, DIFlags Flags, Metadata *ExtraData,
304     StorageType Storage, bool ShouldCreate) {
305   assert(isCanonical(Name) && "Expected canonical MDString");
306   DEFINE_GETIMPL_LOOKUP(DIDerivedType,
307                         (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
308                          AlignInBits, OffsetInBits, DWARFAddressSpace, Flags,
309                          ExtraData));
310   Metadata *Ops[] = {File, Scope, Name, BaseType, ExtraData};
311   DEFINE_GETIMPL_STORE(
312       DIDerivedType, (Tag, Line, SizeInBits, AlignInBits, OffsetInBits,
313                       DWARFAddressSpace, Flags), Ops);
314 }
315 
316 DICompositeType *DICompositeType::getImpl(
317     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *File,
318     unsigned Line, Metadata *Scope, Metadata *BaseType, uint64_t SizeInBits,
319     uint32_t AlignInBits, uint64_t OffsetInBits, DIFlags Flags,
320     Metadata *Elements, unsigned RuntimeLang, Metadata *VTableHolder,
321     Metadata *TemplateParams, MDString *Identifier, Metadata *Discriminator,
322     StorageType Storage, bool ShouldCreate) {
323   assert(isCanonical(Name) && "Expected canonical MDString");
324 
325   // Keep this in sync with buildODRType.
326   DEFINE_GETIMPL_LOOKUP(
327       DICompositeType, (Tag, Name, File, Line, Scope, BaseType, SizeInBits,
328                         AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang,
329                         VTableHolder, TemplateParams, Identifier, Discriminator));
330   Metadata *Ops[] = {File,     Scope,        Name,           BaseType,
331                      Elements, VTableHolder, TemplateParams, Identifier,
332                      Discriminator};
333   DEFINE_GETIMPL_STORE(DICompositeType, (Tag, Line, RuntimeLang, SizeInBits,
334                                          AlignInBits, OffsetInBits, Flags),
335                        Ops);
336 }
337 
338 DICompositeType *DICompositeType::buildODRType(
339     LLVMContext &Context, MDString &Identifier, unsigned Tag, MDString *Name,
340     Metadata *File, unsigned Line, Metadata *Scope, Metadata *BaseType,
341     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
342     DIFlags Flags, Metadata *Elements, unsigned RuntimeLang,
343     Metadata *VTableHolder, Metadata *TemplateParams, Metadata *Discriminator) {
344   assert(!Identifier.getString().empty() && "Expected valid identifier");
345   if (!Context.isODRUniquingDebugTypes())
346     return nullptr;
347   auto *&CT = (*Context.pImpl->DITypeMap)[&Identifier];
348   if (!CT)
349     return CT = DICompositeType::getDistinct(
350                Context, Tag, Name, File, Line, Scope, BaseType, SizeInBits,
351                AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang,
352                VTableHolder, TemplateParams, &Identifier, Discriminator);
353 
354   // Only mutate CT if it's a forward declaration and the new operands aren't.
355   assert(CT->getRawIdentifier() == &Identifier && "Wrong ODR identifier?");
356   if (!CT->isForwardDecl() || (Flags & DINode::FlagFwdDecl))
357     return CT;
358 
359   // Mutate CT in place.  Keep this in sync with getImpl.
360   CT->mutate(Tag, Line, RuntimeLang, SizeInBits, AlignInBits, OffsetInBits,
361              Flags);
362   Metadata *Ops[] = {File,     Scope,        Name,           BaseType,
363                      Elements, VTableHolder, TemplateParams, &Identifier,
364                      Discriminator};
365   assert((std::end(Ops) - std::begin(Ops)) == (int)CT->getNumOperands() &&
366          "Mismatched number of operands");
367   for (unsigned I = 0, E = CT->getNumOperands(); I != E; ++I)
368     if (Ops[I] != CT->getOperand(I))
369       CT->setOperand(I, Ops[I]);
370   return CT;
371 }
372 
373 DICompositeType *DICompositeType::getODRType(
374     LLVMContext &Context, MDString &Identifier, unsigned Tag, MDString *Name,
375     Metadata *File, unsigned Line, Metadata *Scope, Metadata *BaseType,
376     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
377     DIFlags Flags, Metadata *Elements, unsigned RuntimeLang,
378     Metadata *VTableHolder, Metadata *TemplateParams, Metadata *Discriminator) {
379   assert(!Identifier.getString().empty() && "Expected valid identifier");
380   if (!Context.isODRUniquingDebugTypes())
381     return nullptr;
382   auto *&CT = (*Context.pImpl->DITypeMap)[&Identifier];
383   if (!CT)
384     CT = DICompositeType::getDistinct(
385         Context, Tag, Name, File, Line, Scope, BaseType, SizeInBits,
386         AlignInBits, OffsetInBits, Flags, Elements, RuntimeLang, VTableHolder,
387         TemplateParams, &Identifier, Discriminator);
388   return CT;
389 }
390 
391 DICompositeType *DICompositeType::getODRTypeIfExists(LLVMContext &Context,
392                                                      MDString &Identifier) {
393   assert(!Identifier.getString().empty() && "Expected valid identifier");
394   if (!Context.isODRUniquingDebugTypes())
395     return nullptr;
396   return Context.pImpl->DITypeMap->lookup(&Identifier);
397 }
398 
399 DISubroutineType *DISubroutineType::getImpl(LLVMContext &Context, DIFlags Flags,
400                                             uint8_t CC, Metadata *TypeArray,
401                                             StorageType Storage,
402                                             bool ShouldCreate) {
403   DEFINE_GETIMPL_LOOKUP(DISubroutineType, (Flags, CC, TypeArray));
404   Metadata *Ops[] = {nullptr, nullptr, nullptr, TypeArray};
405   DEFINE_GETIMPL_STORE(DISubroutineType, (Flags, CC), Ops);
406 }
407 
408 // FIXME: Implement this string-enum correspondence with a .def file and macros,
409 // so that the association is explicit rather than implied.
410 static const char *ChecksumKindName[DIFile::CSK_Last] = {
411   "CSK_MD5",
412   "CSK_SHA1"
413 };
414 
415 StringRef DIFile::getChecksumKindAsString(ChecksumKind CSKind) {
416   assert(CSKind <= DIFile::CSK_Last && "Invalid checksum kind");
417   // The first space was originally the CSK_None variant, which is now
418   // obsolete, but the space is still reserved in ChecksumKind, so we account
419   // for it here.
420   return ChecksumKindName[CSKind - 1];
421 }
422 
423 Optional<DIFile::ChecksumKind> DIFile::getChecksumKind(StringRef CSKindStr) {
424   return StringSwitch<Optional<DIFile::ChecksumKind>>(CSKindStr)
425       .Case("CSK_MD5", DIFile::CSK_MD5)
426       .Case("CSK_SHA1", DIFile::CSK_SHA1)
427       .Default(None);
428 }
429 
430 DIFile *DIFile::getImpl(LLVMContext &Context, MDString *Filename,
431                         MDString *Directory,
432                         Optional<DIFile::ChecksumInfo<MDString *>> CS,
433                         Optional<MDString *> Source, StorageType Storage,
434                         bool ShouldCreate) {
435   assert(isCanonical(Filename) && "Expected canonical MDString");
436   assert(isCanonical(Directory) && "Expected canonical MDString");
437   assert((!CS || isCanonical(CS->Value)) && "Expected canonical MDString");
438   assert((!Source || isCanonical(*Source)) && "Expected canonical MDString");
439   DEFINE_GETIMPL_LOOKUP(DIFile, (Filename, Directory, CS, Source));
440   Metadata *Ops[] = {Filename, Directory, CS ? CS->Value : nullptr,
441                      Source.getValueOr(nullptr)};
442   DEFINE_GETIMPL_STORE(DIFile, (CS, Source), Ops);
443 }
444 
445 DICompileUnit *DICompileUnit::getImpl(
446     LLVMContext &Context, unsigned SourceLanguage, Metadata *File,
447     MDString *Producer, bool IsOptimized, MDString *Flags,
448     unsigned RuntimeVersion, MDString *SplitDebugFilename,
449     unsigned EmissionKind, Metadata *EnumTypes, Metadata *RetainedTypes,
450     Metadata *GlobalVariables, Metadata *ImportedEntities, Metadata *Macros,
451     uint64_t DWOId, bool SplitDebugInlining, bool DebugInfoForProfiling,
452     bool GnuPubnames, StorageType Storage, bool ShouldCreate) {
453   assert(Storage != Uniqued && "Cannot unique DICompileUnit");
454   assert(isCanonical(Producer) && "Expected canonical MDString");
455   assert(isCanonical(Flags) && "Expected canonical MDString");
456   assert(isCanonical(SplitDebugFilename) && "Expected canonical MDString");
457 
458   Metadata *Ops[] = {
459       File,      Producer,      Flags,           SplitDebugFilename,
460       EnumTypes, RetainedTypes, GlobalVariables, ImportedEntities,
461       Macros};
462   return storeImpl(new (array_lengthof(Ops)) DICompileUnit(
463                        Context, Storage, SourceLanguage, IsOptimized,
464                        RuntimeVersion, EmissionKind, DWOId, SplitDebugInlining,
465                        DebugInfoForProfiling, GnuPubnames, Ops),
466                    Storage);
467 }
468 
469 Optional<DICompileUnit::DebugEmissionKind>
470 DICompileUnit::getEmissionKind(StringRef Str) {
471   return StringSwitch<Optional<DebugEmissionKind>>(Str)
472       .Case("NoDebug", NoDebug)
473       .Case("FullDebug", FullDebug)
474       .Case("LineTablesOnly", LineTablesOnly)
475       .Case("DebugDirectivesOnly", DebugDirectivesOnly)
476       .Default(None);
477 }
478 
479 const char *DICompileUnit::emissionKindString(DebugEmissionKind EK) {
480   switch (EK) {
481   case NoDebug:        return "NoDebug";
482   case FullDebug:      return "FullDebug";
483   case LineTablesOnly: return "LineTablesOnly";
484   case DebugDirectivesOnly: return "DebugDirectviesOnly";
485   }
486   return nullptr;
487 }
488 
489 DISubprogram *DILocalScope::getSubprogram() const {
490   if (auto *Block = dyn_cast<DILexicalBlockBase>(this))
491     return Block->getScope()->getSubprogram();
492   return const_cast<DISubprogram *>(cast<DISubprogram>(this));
493 }
494 
495 DILocalScope *DILocalScope::getNonLexicalBlockFileScope() const {
496   if (auto *File = dyn_cast<DILexicalBlockFile>(this))
497     return File->getScope()->getNonLexicalBlockFileScope();
498   return const_cast<DILocalScope *>(this);
499 }
500 
501 DISubprogram *DISubprogram::getImpl(
502     LLVMContext &Context, Metadata *Scope, MDString *Name,
503     MDString *LinkageName, Metadata *File, unsigned Line, Metadata *Type,
504     bool IsLocalToUnit, bool IsDefinition, unsigned ScopeLine,
505     Metadata *ContainingType, unsigned Virtuality, unsigned VirtualIndex,
506     int ThisAdjustment, DIFlags Flags, bool IsOptimized, Metadata *Unit,
507     Metadata *TemplateParams, Metadata *Declaration, Metadata *RetainedNodes,
508     Metadata *ThrownTypes, StorageType Storage, bool ShouldCreate) {
509   assert(isCanonical(Name) && "Expected canonical MDString");
510   assert(isCanonical(LinkageName) && "Expected canonical MDString");
511   DEFINE_GETIMPL_LOOKUP(
512       DISubprogram, (Scope, Name, LinkageName, File, Line, Type, IsLocalToUnit,
513                      IsDefinition, ScopeLine, ContainingType, Virtuality,
514                      VirtualIndex, ThisAdjustment, Flags, IsOptimized, Unit,
515                      TemplateParams, Declaration, RetainedNodes, ThrownTypes));
516   SmallVector<Metadata *, 11> Ops = {
517       File,        Scope,         Name,           LinkageName,    Type,       Unit,
518       Declaration, RetainedNodes, ContainingType, TemplateParams, ThrownTypes};
519   if (!ThrownTypes) {
520     Ops.pop_back();
521     if (!TemplateParams) {
522       Ops.pop_back();
523       if (!ContainingType)
524         Ops.pop_back();
525     }
526   }
527   DEFINE_GETIMPL_STORE_N(DISubprogram,
528                          (Line, ScopeLine, Virtuality, VirtualIndex,
529                           ThisAdjustment, Flags, IsLocalToUnit, IsDefinition,
530                           IsOptimized),
531                          Ops, Ops.size());
532 }
533 
534 bool DISubprogram::describes(const Function *F) const {
535   assert(F && "Invalid function");
536   if (F->getSubprogram() == this)
537     return true;
538   StringRef Name = getLinkageName();
539   if (Name.empty())
540     Name = getName();
541   return F->getName() == Name;
542 }
543 
544 DILexicalBlock *DILexicalBlock::getImpl(LLVMContext &Context, Metadata *Scope,
545                                         Metadata *File, unsigned Line,
546                                         unsigned Column, StorageType Storage,
547                                         bool ShouldCreate) {
548   // Fixup column.
549   adjustColumn(Column);
550 
551   assert(Scope && "Expected scope");
552   DEFINE_GETIMPL_LOOKUP(DILexicalBlock, (Scope, File, Line, Column));
553   Metadata *Ops[] = {File, Scope};
554   DEFINE_GETIMPL_STORE(DILexicalBlock, (Line, Column), Ops);
555 }
556 
557 DILexicalBlockFile *DILexicalBlockFile::getImpl(LLVMContext &Context,
558                                                 Metadata *Scope, Metadata *File,
559                                                 unsigned Discriminator,
560                                                 StorageType Storage,
561                                                 bool ShouldCreate) {
562   assert(Scope && "Expected scope");
563   DEFINE_GETIMPL_LOOKUP(DILexicalBlockFile, (Scope, File, Discriminator));
564   Metadata *Ops[] = {File, Scope};
565   DEFINE_GETIMPL_STORE(DILexicalBlockFile, (Discriminator), Ops);
566 }
567 
568 DINamespace *DINamespace::getImpl(LLVMContext &Context, Metadata *Scope,
569                                   MDString *Name, bool ExportSymbols,
570                                   StorageType Storage, bool ShouldCreate) {
571   assert(isCanonical(Name) && "Expected canonical MDString");
572   DEFINE_GETIMPL_LOOKUP(DINamespace, (Scope, Name, ExportSymbols));
573   // The nullptr is for DIScope's File operand. This should be refactored.
574   Metadata *Ops[] = {nullptr, Scope, Name};
575   DEFINE_GETIMPL_STORE(DINamespace, (ExportSymbols), Ops);
576 }
577 
578 DIModule *DIModule::getImpl(LLVMContext &Context, Metadata *Scope,
579                             MDString *Name, MDString *ConfigurationMacros,
580                             MDString *IncludePath, MDString *ISysRoot,
581                             StorageType Storage, bool ShouldCreate) {
582   assert(isCanonical(Name) && "Expected canonical MDString");
583   DEFINE_GETIMPL_LOOKUP(
584       DIModule, (Scope, Name, ConfigurationMacros, IncludePath, ISysRoot));
585   Metadata *Ops[] = {Scope, Name, ConfigurationMacros, IncludePath, ISysRoot};
586   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIModule, Ops);
587 }
588 
589 DITemplateTypeParameter *DITemplateTypeParameter::getImpl(LLVMContext &Context,
590                                                           MDString *Name,
591                                                           Metadata *Type,
592                                                           StorageType Storage,
593                                                           bool ShouldCreate) {
594   assert(isCanonical(Name) && "Expected canonical MDString");
595   DEFINE_GETIMPL_LOOKUP(DITemplateTypeParameter, (Name, Type));
596   Metadata *Ops[] = {Name, Type};
597   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DITemplateTypeParameter, Ops);
598 }
599 
600 DITemplateValueParameter *DITemplateValueParameter::getImpl(
601     LLVMContext &Context, unsigned Tag, MDString *Name, Metadata *Type,
602     Metadata *Value, StorageType Storage, bool ShouldCreate) {
603   assert(isCanonical(Name) && "Expected canonical MDString");
604   DEFINE_GETIMPL_LOOKUP(DITemplateValueParameter, (Tag, Name, Type, Value));
605   Metadata *Ops[] = {Name, Type, Value};
606   DEFINE_GETIMPL_STORE(DITemplateValueParameter, (Tag), Ops);
607 }
608 
609 DIGlobalVariable *
610 DIGlobalVariable::getImpl(LLVMContext &Context, Metadata *Scope, MDString *Name,
611                           MDString *LinkageName, Metadata *File, unsigned Line,
612                           Metadata *Type, bool IsLocalToUnit, bool IsDefinition,
613                           Metadata *StaticDataMemberDeclaration,
614                           uint32_t AlignInBits, StorageType Storage,
615                           bool ShouldCreate) {
616   assert(isCanonical(Name) && "Expected canonical MDString");
617   assert(isCanonical(LinkageName) && "Expected canonical MDString");
618   DEFINE_GETIMPL_LOOKUP(DIGlobalVariable,
619                         (Scope, Name, LinkageName, File, Line, Type,
620                          IsLocalToUnit, IsDefinition,
621                          StaticDataMemberDeclaration, AlignInBits));
622   Metadata *Ops[] = {
623       Scope, Name, File, Type, Name, LinkageName, StaticDataMemberDeclaration};
624   DEFINE_GETIMPL_STORE(DIGlobalVariable,
625                        (Line, IsLocalToUnit, IsDefinition, AlignInBits),
626                        Ops);
627 }
628 
629 DILocalVariable *DILocalVariable::getImpl(LLVMContext &Context, Metadata *Scope,
630                                           MDString *Name, Metadata *File,
631                                           unsigned Line, Metadata *Type,
632                                           unsigned Arg, DIFlags Flags,
633                                           uint32_t AlignInBits,
634                                           StorageType Storage,
635                                           bool ShouldCreate) {
636   // 64K ought to be enough for any frontend.
637   assert(Arg <= UINT16_MAX && "Expected argument number to fit in 16-bits");
638 
639   assert(Scope && "Expected scope");
640   assert(isCanonical(Name) && "Expected canonical MDString");
641   DEFINE_GETIMPL_LOOKUP(DILocalVariable,
642                         (Scope, Name, File, Line, Type, Arg, Flags,
643                          AlignInBits));
644   Metadata *Ops[] = {Scope, Name, File, Type};
645   DEFINE_GETIMPL_STORE(DILocalVariable, (Line, Arg, Flags, AlignInBits), Ops);
646 }
647 
648 Optional<uint64_t> DIVariable::getSizeInBits() const {
649   // This is used by the Verifier so be mindful of broken types.
650   const Metadata *RawType = getRawType();
651   while (RawType) {
652     // Try to get the size directly.
653     if (auto *T = dyn_cast<DIType>(RawType))
654       if (uint64_t Size = T->getSizeInBits())
655         return Size;
656 
657     if (auto *DT = dyn_cast<DIDerivedType>(RawType)) {
658       // Look at the base type.
659       RawType = DT->getRawBaseType();
660       continue;
661     }
662 
663     // Missing type or size.
664     break;
665   }
666 
667   // Fail gracefully.
668   return None;
669 }
670 
671 DILabel *DILabel::getImpl(LLVMContext &Context, Metadata *Scope,
672                           MDString *Name, Metadata *File, unsigned Line,
673                           StorageType Storage,
674                           bool ShouldCreate) {
675   assert(Scope && "Expected scope");
676   assert(isCanonical(Name) && "Expected canonical MDString");
677   DEFINE_GETIMPL_LOOKUP(DILabel,
678                         (Scope, Name, File, Line));
679   Metadata *Ops[] = {Scope, Name, File};
680   DEFINE_GETIMPL_STORE(DILabel, (Line), Ops);
681 }
682 
683 DIExpression *DIExpression::getImpl(LLVMContext &Context,
684                                     ArrayRef<uint64_t> Elements,
685                                     StorageType Storage, bool ShouldCreate) {
686   DEFINE_GETIMPL_LOOKUP(DIExpression, (Elements));
687   DEFINE_GETIMPL_STORE_NO_OPS(DIExpression, (Elements));
688 }
689 
690 unsigned DIExpression::ExprOperand::getSize() const {
691   switch (getOp()) {
692   case dwarf::DW_OP_LLVM_fragment:
693     return 3;
694   case dwarf::DW_OP_constu:
695   case dwarf::DW_OP_plus_uconst:
696     return 2;
697   default:
698     return 1;
699   }
700 }
701 
702 bool DIExpression::isValid() const {
703   for (auto I = expr_op_begin(), E = expr_op_end(); I != E; ++I) {
704     // Check that there's space for the operand.
705     if (I->get() + I->getSize() > E->get())
706       return false;
707 
708     // Check that the operand is valid.
709     switch (I->getOp()) {
710     default:
711       return false;
712     case dwarf::DW_OP_LLVM_fragment:
713       // A fragment operator must appear at the end.
714       return I->get() + I->getSize() == E->get();
715     case dwarf::DW_OP_stack_value: {
716       // Must be the last one or followed by a DW_OP_LLVM_fragment.
717       if (I->get() + I->getSize() == E->get())
718         break;
719       auto J = I;
720       if ((++J)->getOp() != dwarf::DW_OP_LLVM_fragment)
721         return false;
722       break;
723     }
724     case dwarf::DW_OP_swap: {
725       // Must be more than one implicit element on the stack.
726 
727       // FIXME: A better way to implement this would be to add a local variable
728       // that keeps track of the stack depth and introduce something like a
729       // DW_LLVM_OP_implicit_location as a placeholder for the location this
730       // DIExpression is attached to, or else pass the number of implicit stack
731       // elements into isValid.
732       if (getNumElements() == 1)
733         return false;
734       break;
735     }
736     case dwarf::DW_OP_constu:
737     case dwarf::DW_OP_plus_uconst:
738     case dwarf::DW_OP_plus:
739     case dwarf::DW_OP_minus:
740     case dwarf::DW_OP_mul:
741     case dwarf::DW_OP_div:
742     case dwarf::DW_OP_mod:
743     case dwarf::DW_OP_or:
744     case dwarf::DW_OP_and:
745     case dwarf::DW_OP_xor:
746     case dwarf::DW_OP_shl:
747     case dwarf::DW_OP_shr:
748     case dwarf::DW_OP_shra:
749     case dwarf::DW_OP_deref:
750     case dwarf::DW_OP_xderef:
751     case dwarf::DW_OP_lit0:
752     case dwarf::DW_OP_not:
753     case dwarf::DW_OP_dup:
754       break;
755     }
756   }
757   return true;
758 }
759 
760 Optional<DIExpression::FragmentInfo>
761 DIExpression::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) {
762   for (auto I = Start; I != End; ++I)
763     if (I->getOp() == dwarf::DW_OP_LLVM_fragment) {
764       DIExpression::FragmentInfo Info = {I->getArg(1), I->getArg(0)};
765       return Info;
766     }
767   return None;
768 }
769 
770 void DIExpression::appendOffset(SmallVectorImpl<uint64_t> &Ops,
771                                 int64_t Offset) {
772   if (Offset > 0) {
773     Ops.push_back(dwarf::DW_OP_plus_uconst);
774     Ops.push_back(Offset);
775   } else if (Offset < 0) {
776     Ops.push_back(dwarf::DW_OP_constu);
777     Ops.push_back(-Offset);
778     Ops.push_back(dwarf::DW_OP_minus);
779   }
780 }
781 
782 bool DIExpression::extractIfOffset(int64_t &Offset) const {
783   if (getNumElements() == 0) {
784     Offset = 0;
785     return true;
786   }
787 
788   if (getNumElements() == 2 && Elements[0] == dwarf::DW_OP_plus_uconst) {
789     Offset = Elements[1];
790     return true;
791   }
792 
793   if (getNumElements() == 3 && Elements[0] == dwarf::DW_OP_constu) {
794     if (Elements[2] == dwarf::DW_OP_plus) {
795       Offset = Elements[1];
796       return true;
797     }
798     if (Elements[2] == dwarf::DW_OP_minus) {
799       Offset = -Elements[1];
800       return true;
801     }
802   }
803 
804   return false;
805 }
806 
807 DIExpression *DIExpression::prepend(const DIExpression *Expr, bool DerefBefore,
808                                     int64_t Offset, bool DerefAfter,
809                                     bool StackValue) {
810   SmallVector<uint64_t, 8> Ops;
811   if (DerefBefore)
812     Ops.push_back(dwarf::DW_OP_deref);
813 
814   appendOffset(Ops, Offset);
815   if (DerefAfter)
816     Ops.push_back(dwarf::DW_OP_deref);
817 
818   return prependOpcodes(Expr, Ops, StackValue);
819 }
820 
821 DIExpression *DIExpression::prependOpcodes(const DIExpression *Expr,
822                                            SmallVectorImpl<uint64_t> &Ops,
823                                            bool StackValue) {
824   assert(Expr && "Can't prepend ops to this expression");
825 
826   // If there are no ops to prepend, do not even add the DW_OP_stack_value.
827   if (Ops.empty())
828     StackValue = false;
829   for (auto Op : Expr->expr_ops()) {
830     // A DW_OP_stack_value comes at the end, but before a DW_OP_LLVM_fragment.
831     if (StackValue) {
832       if (Op.getOp() == dwarf::DW_OP_stack_value)
833         StackValue = false;
834       else if (Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
835         Ops.push_back(dwarf::DW_OP_stack_value);
836         StackValue = false;
837       }
838     }
839     Op.appendToVector(Ops);
840   }
841   if (StackValue)
842     Ops.push_back(dwarf::DW_OP_stack_value);
843   return DIExpression::get(Expr->getContext(), Ops);
844 }
845 
846 DIExpression *DIExpression::append(const DIExpression *Expr,
847                                    ArrayRef<uint64_t> Ops) {
848   assert(Expr && !Ops.empty() && "Can't append ops to this expression");
849 
850   // Copy Expr's current op list.
851   SmallVector<uint64_t, 16> NewOps;
852   for (auto Op : Expr->expr_ops()) {
853     // Append new opcodes before DW_OP_{stack_value, LLVM_fragment}.
854     if (Op.getOp() == dwarf::DW_OP_stack_value ||
855         Op.getOp() == dwarf::DW_OP_LLVM_fragment) {
856       NewOps.append(Ops.begin(), Ops.end());
857 
858       // Ensure that the new opcodes are only appended once.
859       Ops = None;
860     }
861     Op.appendToVector(NewOps);
862   }
863 
864   NewOps.append(Ops.begin(), Ops.end());
865   return DIExpression::get(Expr->getContext(), NewOps);
866 }
867 
868 DIExpression *DIExpression::appendToStack(const DIExpression *Expr,
869                                           ArrayRef<uint64_t> Ops) {
870   assert(Expr && !Ops.empty() && "Can't append ops to this expression");
871   assert(none_of(Ops,
872                  [](uint64_t Op) {
873                    return Op == dwarf::DW_OP_stack_value ||
874                           Op == dwarf::DW_OP_LLVM_fragment;
875                  }) &&
876          "Can't append this op");
877 
878   // Append a DW_OP_deref after Expr's current op list if it's non-empty and
879   // has no DW_OP_stack_value.
880   //
881   // Match .* DW_OP_stack_value (DW_OP_LLVM_fragment A B)?.
882   Optional<FragmentInfo> FI = Expr->getFragmentInfo();
883   unsigned DropUntilStackValue = FI.hasValue() ? 3 : 0;
884   ArrayRef<uint64_t> ExprOpsBeforeFragment =
885       Expr->getElements().drop_back(DropUntilStackValue);
886   bool NeedsDeref = (Expr->getNumElements() > DropUntilStackValue) &&
887                     (ExprOpsBeforeFragment.back() != dwarf::DW_OP_stack_value);
888   bool NeedsStackValue = NeedsDeref || ExprOpsBeforeFragment.empty();
889 
890   // Append a DW_OP_deref after Expr's current op list if needed, then append
891   // the new ops, and finally ensure that a single DW_OP_stack_value is present.
892   SmallVector<uint64_t, 16> NewOps;
893   if (NeedsDeref)
894     NewOps.push_back(dwarf::DW_OP_deref);
895   NewOps.append(Ops.begin(), Ops.end());
896   if (NeedsStackValue)
897     NewOps.push_back(dwarf::DW_OP_stack_value);
898   return DIExpression::append(Expr, NewOps);
899 }
900 
901 Optional<DIExpression *> DIExpression::createFragmentExpression(
902     const DIExpression *Expr, unsigned OffsetInBits, unsigned SizeInBits) {
903   SmallVector<uint64_t, 8> Ops;
904   // Copy over the expression, but leave off any trailing DW_OP_LLVM_fragment.
905   if (Expr) {
906     for (auto Op : Expr->expr_ops()) {
907       switch (Op.getOp()) {
908       default: break;
909       case dwarf::DW_OP_plus:
910       case dwarf::DW_OP_minus:
911         // We can't safely split arithmetic into multiple fragments because we
912         // can't express carry-over between fragments.
913         //
914         // FIXME: We *could* preserve the lowest fragment of a constant offset
915         // operation if the offset fits into SizeInBits.
916         return None;
917       case dwarf::DW_OP_LLVM_fragment: {
918         // Make the new offset point into the existing fragment.
919         uint64_t FragmentOffsetInBits = Op.getArg(0);
920         uint64_t FragmentSizeInBits = Op.getArg(1);
921         (void)FragmentSizeInBits;
922         assert((OffsetInBits + SizeInBits <= FragmentSizeInBits) &&
923                "new fragment outside of original fragment");
924         OffsetInBits += FragmentOffsetInBits;
925         continue;
926       }
927       }
928       Op.appendToVector(Ops);
929     }
930   }
931   Ops.push_back(dwarf::DW_OP_LLVM_fragment);
932   Ops.push_back(OffsetInBits);
933   Ops.push_back(SizeInBits);
934   return DIExpression::get(Expr->getContext(), Ops);
935 }
936 
937 bool DIExpression::isConstant() const {
938   // Recognize DW_OP_constu C DW_OP_stack_value (DW_OP_LLVM_fragment Len Ofs)?.
939   if (getNumElements() != 3 && getNumElements() != 6)
940     return false;
941   if (getElement(0) != dwarf::DW_OP_constu ||
942       getElement(2) != dwarf::DW_OP_stack_value)
943     return false;
944   if (getNumElements() == 6 && getElement(3) != dwarf::DW_OP_LLVM_fragment)
945     return false;
946   return true;
947 }
948 
949 DIGlobalVariableExpression *
950 DIGlobalVariableExpression::getImpl(LLVMContext &Context, Metadata *Variable,
951                                     Metadata *Expression, StorageType Storage,
952                                     bool ShouldCreate) {
953   DEFINE_GETIMPL_LOOKUP(DIGlobalVariableExpression, (Variable, Expression));
954   Metadata *Ops[] = {Variable, Expression};
955   DEFINE_GETIMPL_STORE_NO_CONSTRUCTOR_ARGS(DIGlobalVariableExpression, Ops);
956 }
957 
958 DIObjCProperty *DIObjCProperty::getImpl(
959     LLVMContext &Context, MDString *Name, Metadata *File, unsigned Line,
960     MDString *GetterName, MDString *SetterName, unsigned Attributes,
961     Metadata *Type, StorageType Storage, bool ShouldCreate) {
962   assert(isCanonical(Name) && "Expected canonical MDString");
963   assert(isCanonical(GetterName) && "Expected canonical MDString");
964   assert(isCanonical(SetterName) && "Expected canonical MDString");
965   DEFINE_GETIMPL_LOOKUP(DIObjCProperty, (Name, File, Line, GetterName,
966                                          SetterName, Attributes, Type));
967   Metadata *Ops[] = {Name, File, GetterName, SetterName, Type};
968   DEFINE_GETIMPL_STORE(DIObjCProperty, (Line, Attributes), Ops);
969 }
970 
971 DIImportedEntity *DIImportedEntity::getImpl(LLVMContext &Context, unsigned Tag,
972                                             Metadata *Scope, Metadata *Entity,
973                                             Metadata *File, unsigned Line,
974                                             MDString *Name, StorageType Storage,
975                                             bool ShouldCreate) {
976   assert(isCanonical(Name) && "Expected canonical MDString");
977   DEFINE_GETIMPL_LOOKUP(DIImportedEntity,
978                         (Tag, Scope, Entity, File, Line, Name));
979   Metadata *Ops[] = {Scope, Entity, Name, File};
980   DEFINE_GETIMPL_STORE(DIImportedEntity, (Tag, Line), Ops);
981 }
982 
983 DIMacro *DIMacro::getImpl(LLVMContext &Context, unsigned MIType,
984                           unsigned Line, MDString *Name, MDString *Value,
985                           StorageType Storage, bool ShouldCreate) {
986   assert(isCanonical(Name) && "Expected canonical MDString");
987   DEFINE_GETIMPL_LOOKUP(DIMacro, (MIType, Line, Name, Value));
988   Metadata *Ops[] = { Name, Value };
989   DEFINE_GETIMPL_STORE(DIMacro, (MIType, Line), Ops);
990 }
991 
992 DIMacroFile *DIMacroFile::getImpl(LLVMContext &Context, unsigned MIType,
993                                   unsigned Line, Metadata *File,
994                                   Metadata *Elements, StorageType Storage,
995                                   bool ShouldCreate) {
996   DEFINE_GETIMPL_LOOKUP(DIMacroFile,
997                         (MIType, Line, File, Elements));
998   Metadata *Ops[] = { File, Elements };
999   DEFINE_GETIMPL_STORE(DIMacroFile, (MIType, Line), Ops);
1000 }
1001