1 //===--- DIBuilder.cpp - Debug Information Builder ------------------------===//
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 DIBuilder.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/IR/DIBuilder.h"
15 #include "LLVMContextImpl.h"
16 #include "llvm/ADT/STLExtras.h"
17 #include "llvm/BinaryFormat/Dwarf.h"
18 #include "llvm/IR/Constants.h"
19 #include "llvm/IR/DebugInfo.h"
20 #include "llvm/IR/IntrinsicInst.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/Support/Debug.h"
23 
24 using namespace llvm;
25 using namespace llvm::dwarf;
26 
27 DIBuilder::DIBuilder(Module &m, bool AllowUnresolvedNodes)
28   : M(m), VMContext(M.getContext()), CUNode(nullptr),
29       DeclareFn(nullptr), ValueFn(nullptr),
30       AllowUnresolvedNodes(AllowUnresolvedNodes) {}
31 
32 void DIBuilder::trackIfUnresolved(MDNode *N) {
33   if (!N)
34     return;
35   if (N->isResolved())
36     return;
37 
38   assert(AllowUnresolvedNodes && "Cannot handle unresolved nodes");
39   UnresolvedNodes.emplace_back(N);
40 }
41 
42 void DIBuilder::finalizeSubprogram(DISubprogram *SP) {
43   MDTuple *Temp = SP->getVariables().get();
44   if (!Temp || !Temp->isTemporary())
45     return;
46 
47   SmallVector<Metadata *, 4> Variables;
48 
49   auto PV = PreservedVariables.find(SP);
50   if (PV != PreservedVariables.end())
51     Variables.append(PV->second.begin(), PV->second.end());
52 
53   DINodeArray AV = getOrCreateArray(Variables);
54   TempMDTuple(Temp)->replaceAllUsesWith(AV.get());
55 }
56 
57 void DIBuilder::finalize() {
58   if (!CUNode) {
59     assert(!AllowUnresolvedNodes &&
60            "creating type nodes without a CU is not supported");
61     return;
62   }
63 
64   CUNode->replaceEnumTypes(MDTuple::get(VMContext, AllEnumTypes));
65 
66   SmallVector<Metadata *, 16> RetainValues;
67   // Declarations and definitions of the same type may be retained. Some
68   // clients RAUW these pairs, leaving duplicates in the retained types
69   // list. Use a set to remove the duplicates while we transform the
70   // TrackingVHs back into Values.
71   SmallPtrSet<Metadata *, 16> RetainSet;
72   for (unsigned I = 0, E = AllRetainTypes.size(); I < E; I++)
73     if (RetainSet.insert(AllRetainTypes[I]).second)
74       RetainValues.push_back(AllRetainTypes[I]);
75 
76   if (!RetainValues.empty())
77     CUNode->replaceRetainedTypes(MDTuple::get(VMContext, RetainValues));
78 
79   DISubprogramArray SPs = MDTuple::get(VMContext, AllSubprograms);
80   for (auto *SP : SPs)
81     finalizeSubprogram(SP);
82   for (auto *N : RetainValues)
83     if (auto *SP = dyn_cast<DISubprogram>(N))
84       finalizeSubprogram(SP);
85 
86   if (!AllGVs.empty())
87     CUNode->replaceGlobalVariables(MDTuple::get(VMContext, AllGVs));
88 
89   if (!AllImportedModules.empty())
90     CUNode->replaceImportedEntities(MDTuple::get(
91         VMContext, SmallVector<Metadata *, 16>(AllImportedModules.begin(),
92                                                AllImportedModules.end())));
93 
94   for (const auto &I : AllMacrosPerParent) {
95     // DIMacroNode's with nullptr parent are DICompileUnit direct children.
96     if (!I.first) {
97       CUNode->replaceMacros(MDTuple::get(VMContext, I.second.getArrayRef()));
98       continue;
99     }
100     // Otherwise, it must be a temporary DIMacroFile that need to be resolved.
101     auto *TMF = cast<DIMacroFile>(I.first);
102     auto *MF = DIMacroFile::get(VMContext, dwarf::DW_MACINFO_start_file,
103                                 TMF->getLine(), TMF->getFile(),
104                                 getOrCreateMacroArray(I.second.getArrayRef()));
105     replaceTemporary(llvm::TempDIMacroNode(TMF), MF);
106   }
107 
108   // Now that all temp nodes have been replaced or deleted, resolve remaining
109   // cycles.
110   for (const auto &N : UnresolvedNodes)
111     if (N && !N->isResolved())
112       N->resolveCycles();
113   UnresolvedNodes.clear();
114 
115   // Can't handle unresolved nodes anymore.
116   AllowUnresolvedNodes = false;
117 }
118 
119 /// If N is compile unit return NULL otherwise return N.
120 static DIScope *getNonCompileUnitScope(DIScope *N) {
121   if (!N || isa<DICompileUnit>(N))
122     return nullptr;
123   return cast<DIScope>(N);
124 }
125 
126 DICompileUnit *DIBuilder::createCompileUnit(
127     unsigned Lang, DIFile *File, StringRef Producer, bool isOptimized,
128     StringRef Flags, unsigned RunTimeVer, StringRef SplitName,
129     DICompileUnit::DebugEmissionKind Kind, uint64_t DWOId,
130     bool SplitDebugInlining, bool DebugInfoForProfiling) {
131 
132   assert(((Lang <= dwarf::DW_LANG_Fortran08 && Lang >= dwarf::DW_LANG_C89) ||
133           (Lang <= dwarf::DW_LANG_hi_user && Lang >= dwarf::DW_LANG_lo_user)) &&
134          "Invalid Language tag");
135 
136   assert(!CUNode && "Can only make one compile unit per DIBuilder instance");
137   CUNode = DICompileUnit::getDistinct(
138       VMContext, Lang, File, Producer, isOptimized, Flags, RunTimeVer,
139       SplitName, Kind, nullptr, nullptr, nullptr, nullptr, nullptr, DWOId,
140       SplitDebugInlining, DebugInfoForProfiling);
141 
142   // Create a named metadata so that it is easier to find cu in a module.
143   NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
144   NMD->addOperand(CUNode);
145   trackIfUnresolved(CUNode);
146   return CUNode;
147 }
148 
149 static DIImportedEntity *
150 createImportedModule(LLVMContext &C, dwarf::Tag Tag, DIScope *Context,
151                      Metadata *NS, unsigned Line, StringRef Name,
152                      SmallVectorImpl<TrackingMDNodeRef> &AllImportedModules) {
153   unsigned EntitiesCount = C.pImpl->DIImportedEntitys.size();
154   auto *M = DIImportedEntity::get(C, Tag, Context, DINodeRef(NS), Line, Name);
155   if (EntitiesCount < C.pImpl->DIImportedEntitys.size())
156     // A new Imported Entity was just added to the context.
157     // Add it to the Imported Modules list.
158     AllImportedModules.emplace_back(M);
159   return M;
160 }
161 
162 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
163                                                   DINamespace *NS,
164                                                   unsigned Line) {
165   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
166                                 Context, NS, Line, StringRef(), AllImportedModules);
167 }
168 
169 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
170                                                   DIImportedEntity *NS,
171                                                   unsigned Line) {
172   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
173                                 Context, NS, Line, StringRef(), AllImportedModules);
174 }
175 
176 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context, DIModule *M,
177                                                   unsigned Line) {
178   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
179                                 Context, M, Line, StringRef(), AllImportedModules);
180 }
181 
182 DIImportedEntity *DIBuilder::createImportedDeclaration(DIScope *Context,
183                                                        DINode *Decl,
184                                                        unsigned Line,
185                                                        StringRef Name) {
186   // Make sure to use the unique identifier based metadata reference for
187   // types that have one.
188   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_declaration,
189                                 Context, Decl, Line, Name, AllImportedModules);
190 }
191 
192 DIFile *DIBuilder::createFile(StringRef Filename, StringRef Directory,
193                               DIFile::ChecksumKind CSKind, StringRef Checksum) {
194   return DIFile::get(VMContext, Filename, Directory, CSKind, Checksum);
195 }
196 
197 DIMacro *DIBuilder::createMacro(DIMacroFile *Parent, unsigned LineNumber,
198                                 unsigned MacroType, StringRef Name,
199                                 StringRef Value) {
200   assert(!Name.empty() && "Unable to create macro without name");
201   assert((MacroType == dwarf::DW_MACINFO_undef ||
202           MacroType == dwarf::DW_MACINFO_define) &&
203          "Unexpected macro type");
204   auto *M = DIMacro::get(VMContext, MacroType, LineNumber, Name, Value);
205   AllMacrosPerParent[Parent].insert(M);
206   return M;
207 }
208 
209 DIMacroFile *DIBuilder::createTempMacroFile(DIMacroFile *Parent,
210                                             unsigned LineNumber, DIFile *File) {
211   auto *MF = DIMacroFile::getTemporary(VMContext, dwarf::DW_MACINFO_start_file,
212                                        LineNumber, File, DIMacroNodeArray())
213                  .release();
214   AllMacrosPerParent[Parent].insert(MF);
215   // Add the new temporary DIMacroFile to the macro per parent map as a parent.
216   // This is needed to assure DIMacroFile with no children to have an entry in
217   // the map. Otherwise, it will not be resolved in DIBuilder::finalize().
218   AllMacrosPerParent.insert({MF, {}});
219   return MF;
220 }
221 
222 DIEnumerator *DIBuilder::createEnumerator(StringRef Name, int64_t Val) {
223   assert(!Name.empty() && "Unable to create enumerator without name");
224   return DIEnumerator::get(VMContext, Val, Name);
225 }
226 
227 DIBasicType *DIBuilder::createUnspecifiedType(StringRef Name) {
228   assert(!Name.empty() && "Unable to create type without name");
229   return DIBasicType::get(VMContext, dwarf::DW_TAG_unspecified_type, Name);
230 }
231 
232 DIBasicType *DIBuilder::createNullPtrType() {
233   return createUnspecifiedType("decltype(nullptr)");
234 }
235 
236 DIBasicType *DIBuilder::createBasicType(StringRef Name, uint64_t SizeInBits,
237                                         unsigned Encoding) {
238   assert(!Name.empty() && "Unable to create type without name");
239   return DIBasicType::get(VMContext, dwarf::DW_TAG_base_type, Name, SizeInBits,
240                           0, Encoding);
241 }
242 
243 DIDerivedType *DIBuilder::createQualifiedType(unsigned Tag, DIType *FromTy) {
244   return DIDerivedType::get(VMContext, Tag, "", nullptr, 0, nullptr, FromTy, 0,
245                             0, 0, None, DINode::FlagZero);
246 }
247 
248 DIDerivedType *DIBuilder::createPointerType(
249     DIType *PointeeTy,
250     uint64_t SizeInBits,
251     uint32_t AlignInBits,
252     Optional<unsigned> DWARFAddressSpace,
253     StringRef Name) {
254   // FIXME: Why is there a name here?
255   return DIDerivedType::get(VMContext, dwarf::DW_TAG_pointer_type, Name,
256                             nullptr, 0, nullptr, PointeeTy, SizeInBits,
257                             AlignInBits, 0, DWARFAddressSpace,
258                             DINode::FlagZero);
259 }
260 
261 DIDerivedType *DIBuilder::createMemberPointerType(DIType *PointeeTy,
262                                                   DIType *Base,
263                                                   uint64_t SizeInBits,
264                                                   uint32_t AlignInBits,
265                                                   DINode::DIFlags Flags) {
266   return DIDerivedType::get(VMContext, dwarf::DW_TAG_ptr_to_member_type, "",
267                             nullptr, 0, nullptr, PointeeTy, SizeInBits,
268                             AlignInBits, 0, None, Flags, Base);
269 }
270 
271 DIDerivedType *DIBuilder::createReferenceType(
272     unsigned Tag, DIType *RTy,
273     uint64_t SizeInBits,
274     uint32_t AlignInBits,
275     Optional<unsigned> DWARFAddressSpace) {
276   assert(RTy && "Unable to create reference type");
277   return DIDerivedType::get(VMContext, Tag, "", nullptr, 0, nullptr, RTy,
278                             SizeInBits, AlignInBits, 0, DWARFAddressSpace,
279                             DINode::FlagZero);
280 }
281 
282 DIDerivedType *DIBuilder::createTypedef(DIType *Ty, StringRef Name,
283                                         DIFile *File, unsigned LineNo,
284                                         DIScope *Context) {
285   return DIDerivedType::get(VMContext, dwarf::DW_TAG_typedef, Name, File,
286                             LineNo, getNonCompileUnitScope(Context), Ty, 0, 0,
287                             0, None, DINode::FlagZero);
288 }
289 
290 DIDerivedType *DIBuilder::createFriend(DIType *Ty, DIType *FriendTy) {
291   assert(Ty && "Invalid type!");
292   assert(FriendTy && "Invalid friend type!");
293   return DIDerivedType::get(VMContext, dwarf::DW_TAG_friend, "", nullptr, 0, Ty,
294                             FriendTy, 0, 0, 0, None, DINode::FlagZero);
295 }
296 
297 DIDerivedType *DIBuilder::createInheritance(DIType *Ty, DIType *BaseTy,
298                                             uint64_t BaseOffset,
299                                             DINode::DIFlags Flags) {
300   assert(Ty && "Unable to create inheritance");
301   return DIDerivedType::get(VMContext, dwarf::DW_TAG_inheritance, "", nullptr,
302                             0, Ty, BaseTy, 0, 0, BaseOffset, None, Flags);
303 }
304 
305 DIDerivedType *DIBuilder::createMemberType(DIScope *Scope, StringRef Name,
306                                            DIFile *File, unsigned LineNumber,
307                                            uint64_t SizeInBits,
308                                            uint32_t AlignInBits,
309                                            uint64_t OffsetInBits,
310                                            DINode::DIFlags Flags, DIType *Ty) {
311   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
312                             LineNumber, getNonCompileUnitScope(Scope), Ty,
313                             SizeInBits, AlignInBits, OffsetInBits, None, Flags);
314 }
315 
316 static ConstantAsMetadata *getConstantOrNull(Constant *C) {
317   if (C)
318     return ConstantAsMetadata::get(C);
319   return nullptr;
320 }
321 
322 DIDerivedType *DIBuilder::createBitFieldMemberType(
323     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
324     uint64_t SizeInBits, uint64_t OffsetInBits, uint64_t StorageOffsetInBits,
325     DINode::DIFlags Flags, DIType *Ty) {
326   Flags |= DINode::FlagBitField;
327   return DIDerivedType::get(
328       VMContext, dwarf::DW_TAG_member, Name, File, LineNumber,
329       getNonCompileUnitScope(Scope), Ty, SizeInBits, /* AlignInBits */ 0,
330       OffsetInBits, None, Flags,
331       ConstantAsMetadata::get(ConstantInt::get(IntegerType::get(VMContext, 64),
332                                                StorageOffsetInBits)));
333 }
334 
335 DIDerivedType *
336 DIBuilder::createStaticMemberType(DIScope *Scope, StringRef Name, DIFile *File,
337                                   unsigned LineNumber, DIType *Ty,
338                                   DINode::DIFlags Flags, llvm::Constant *Val,
339                                   uint32_t AlignInBits) {
340   Flags |= DINode::FlagStaticMember;
341   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
342                             LineNumber, getNonCompileUnitScope(Scope), Ty, 0,
343                             AlignInBits, 0, None, Flags,
344                             getConstantOrNull(Val));
345 }
346 
347 DIDerivedType *
348 DIBuilder::createObjCIVar(StringRef Name, DIFile *File, unsigned LineNumber,
349                           uint64_t SizeInBits, uint32_t AlignInBits,
350                           uint64_t OffsetInBits, DINode::DIFlags Flags,
351                           DIType *Ty, MDNode *PropertyNode) {
352   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
353                             LineNumber, getNonCompileUnitScope(File), Ty,
354                             SizeInBits, AlignInBits, OffsetInBits, None, Flags,
355                             PropertyNode);
356 }
357 
358 DIObjCProperty *
359 DIBuilder::createObjCProperty(StringRef Name, DIFile *File, unsigned LineNumber,
360                               StringRef GetterName, StringRef SetterName,
361                               unsigned PropertyAttributes, DIType *Ty) {
362   return DIObjCProperty::get(VMContext, Name, File, LineNumber, GetterName,
363                              SetterName, PropertyAttributes, Ty);
364 }
365 
366 DITemplateTypeParameter *
367 DIBuilder::createTemplateTypeParameter(DIScope *Context, StringRef Name,
368                                        DIType *Ty) {
369   assert((!Context || isa<DICompileUnit>(Context)) && "Expected compile unit");
370   return DITemplateTypeParameter::get(VMContext, Name, Ty);
371 }
372 
373 static DITemplateValueParameter *
374 createTemplateValueParameterHelper(LLVMContext &VMContext, unsigned Tag,
375                                    DIScope *Context, StringRef Name, DIType *Ty,
376                                    Metadata *MD) {
377   assert((!Context || isa<DICompileUnit>(Context)) && "Expected compile unit");
378   return DITemplateValueParameter::get(VMContext, Tag, Name, Ty, MD);
379 }
380 
381 DITemplateValueParameter *
382 DIBuilder::createTemplateValueParameter(DIScope *Context, StringRef Name,
383                                         DIType *Ty, Constant *Val) {
384   return createTemplateValueParameterHelper(
385       VMContext, dwarf::DW_TAG_template_value_parameter, Context, Name, Ty,
386       getConstantOrNull(Val));
387 }
388 
389 DITemplateValueParameter *
390 DIBuilder::createTemplateTemplateParameter(DIScope *Context, StringRef Name,
391                                            DIType *Ty, StringRef Val) {
392   return createTemplateValueParameterHelper(
393       VMContext, dwarf::DW_TAG_GNU_template_template_param, Context, Name, Ty,
394       MDString::get(VMContext, Val));
395 }
396 
397 DITemplateValueParameter *
398 DIBuilder::createTemplateParameterPack(DIScope *Context, StringRef Name,
399                                        DIType *Ty, DINodeArray Val) {
400   return createTemplateValueParameterHelper(
401       VMContext, dwarf::DW_TAG_GNU_template_parameter_pack, Context, Name, Ty,
402       Val.get());
403 }
404 
405 DICompositeType *DIBuilder::createClassType(
406     DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
407     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
408     DINode::DIFlags Flags, DIType *DerivedFrom, DINodeArray Elements,
409     DIType *VTableHolder, MDNode *TemplateParams, StringRef UniqueIdentifier) {
410   assert((!Context || isa<DIScope>(Context)) &&
411          "createClassType should be called with a valid Context");
412 
413   auto *R = DICompositeType::get(
414       VMContext, dwarf::DW_TAG_structure_type, Name, File, LineNumber,
415       getNonCompileUnitScope(Context), DerivedFrom, SizeInBits, AlignInBits,
416       OffsetInBits, Flags, Elements, 0, VTableHolder,
417       cast_or_null<MDTuple>(TemplateParams), UniqueIdentifier);
418   trackIfUnresolved(R);
419   return R;
420 }
421 
422 DICompositeType *DIBuilder::createStructType(
423     DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
424     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
425     DIType *DerivedFrom, DINodeArray Elements, unsigned RunTimeLang,
426     DIType *VTableHolder, StringRef UniqueIdentifier) {
427   auto *R = DICompositeType::get(
428       VMContext, dwarf::DW_TAG_structure_type, Name, File, LineNumber,
429       getNonCompileUnitScope(Context), DerivedFrom, SizeInBits, AlignInBits, 0,
430       Flags, Elements, RunTimeLang, VTableHolder, nullptr, UniqueIdentifier);
431   trackIfUnresolved(R);
432   return R;
433 }
434 
435 DICompositeType *DIBuilder::createUnionType(
436     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
437     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
438     DINodeArray Elements, unsigned RunTimeLang, StringRef UniqueIdentifier) {
439   auto *R = DICompositeType::get(
440       VMContext, dwarf::DW_TAG_union_type, Name, File, LineNumber,
441       getNonCompileUnitScope(Scope), nullptr, SizeInBits, AlignInBits, 0, Flags,
442       Elements, RunTimeLang, nullptr, nullptr, UniqueIdentifier);
443   trackIfUnresolved(R);
444   return R;
445 }
446 
447 DISubroutineType *DIBuilder::createSubroutineType(DITypeRefArray ParameterTypes,
448                                                   DINode::DIFlags Flags,
449                                                   unsigned CC) {
450   return DISubroutineType::get(VMContext, Flags, CC, ParameterTypes);
451 }
452 
453 DICompositeType *DIBuilder::createEnumerationType(
454     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
455     uint64_t SizeInBits, uint32_t AlignInBits, DINodeArray Elements,
456     DIType *UnderlyingType, StringRef UniqueIdentifier) {
457   auto *CTy = DICompositeType::get(
458       VMContext, dwarf::DW_TAG_enumeration_type, Name, File, LineNumber,
459       getNonCompileUnitScope(Scope), UnderlyingType, SizeInBits, AlignInBits, 0,
460       DINode::FlagZero, Elements, 0, nullptr, nullptr, UniqueIdentifier);
461   AllEnumTypes.push_back(CTy);
462   trackIfUnresolved(CTy);
463   return CTy;
464 }
465 
466 DICompositeType *DIBuilder::createArrayType(uint64_t Size,
467                                             uint32_t AlignInBits, DIType *Ty,
468                                             DINodeArray Subscripts) {
469   auto *R = DICompositeType::get(VMContext, dwarf::DW_TAG_array_type, "",
470                                  nullptr, 0, nullptr, Ty, Size, AlignInBits, 0,
471                                  DINode::FlagZero, Subscripts, 0, nullptr);
472   trackIfUnresolved(R);
473   return R;
474 }
475 
476 DICompositeType *DIBuilder::createVectorType(uint64_t Size,
477                                              uint32_t AlignInBits, DIType *Ty,
478                                              DINodeArray Subscripts) {
479   auto *R = DICompositeType::get(VMContext, dwarf::DW_TAG_array_type, "",
480                                  nullptr, 0, nullptr, Ty, Size, AlignInBits, 0,
481                                  DINode::FlagVector, Subscripts, 0, nullptr);
482   trackIfUnresolved(R);
483   return R;
484 }
485 
486 static DIType *createTypeWithFlags(LLVMContext &Context, DIType *Ty,
487                                    DINode::DIFlags FlagsToSet) {
488   auto NewTy = Ty->clone();
489   NewTy->setFlags(NewTy->getFlags() | FlagsToSet);
490   return MDNode::replaceWithUniqued(std::move(NewTy));
491 }
492 
493 DIType *DIBuilder::createArtificialType(DIType *Ty) {
494   // FIXME: Restrict this to the nodes where it's valid.
495   if (Ty->isArtificial())
496     return Ty;
497   return createTypeWithFlags(VMContext, Ty, DINode::FlagArtificial);
498 }
499 
500 DIType *DIBuilder::createObjectPointerType(DIType *Ty) {
501   // FIXME: Restrict this to the nodes where it's valid.
502   if (Ty->isObjectPointer())
503     return Ty;
504   DINode::DIFlags Flags = DINode::FlagObjectPointer | DINode::FlagArtificial;
505   return createTypeWithFlags(VMContext, Ty, Flags);
506 }
507 
508 void DIBuilder::retainType(DIScope *T) {
509   assert(T && "Expected non-null type");
510   assert((isa<DIType>(T) || (isa<DISubprogram>(T) &&
511                              cast<DISubprogram>(T)->isDefinition() == false)) &&
512          "Expected type or subprogram declaration");
513   AllRetainTypes.emplace_back(T);
514 }
515 
516 DIBasicType *DIBuilder::createUnspecifiedParameter() { return nullptr; }
517 
518 DICompositeType *
519 DIBuilder::createForwardDecl(unsigned Tag, StringRef Name, DIScope *Scope,
520                              DIFile *F, unsigned Line, unsigned RuntimeLang,
521                              uint64_t SizeInBits, uint32_t AlignInBits,
522                              StringRef UniqueIdentifier) {
523   // FIXME: Define in terms of createReplaceableForwardDecl() by calling
524   // replaceWithUniqued().
525   auto *RetTy = DICompositeType::get(
526       VMContext, Tag, Name, F, Line, getNonCompileUnitScope(Scope), nullptr,
527       SizeInBits, AlignInBits, 0, DINode::FlagFwdDecl, nullptr, RuntimeLang,
528       nullptr, nullptr, UniqueIdentifier);
529   trackIfUnresolved(RetTy);
530   return RetTy;
531 }
532 
533 DICompositeType *DIBuilder::createReplaceableCompositeType(
534     unsigned Tag, StringRef Name, DIScope *Scope, DIFile *F, unsigned Line,
535     unsigned RuntimeLang, uint64_t SizeInBits, uint32_t AlignInBits,
536     DINode::DIFlags Flags, StringRef UniqueIdentifier) {
537   auto *RetTy =
538       DICompositeType::getTemporary(
539           VMContext, Tag, Name, F, Line, getNonCompileUnitScope(Scope), nullptr,
540           SizeInBits, AlignInBits, 0, Flags, nullptr, RuntimeLang, nullptr,
541           nullptr, UniqueIdentifier)
542           .release();
543   trackIfUnresolved(RetTy);
544   return RetTy;
545 }
546 
547 DINodeArray DIBuilder::getOrCreateArray(ArrayRef<Metadata *> Elements) {
548   return MDTuple::get(VMContext, Elements);
549 }
550 
551 DIMacroNodeArray
552 DIBuilder::getOrCreateMacroArray(ArrayRef<Metadata *> Elements) {
553   return MDTuple::get(VMContext, Elements);
554 }
555 
556 DITypeRefArray DIBuilder::getOrCreateTypeArray(ArrayRef<Metadata *> Elements) {
557   SmallVector<llvm::Metadata *, 16> Elts;
558   for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
559     if (Elements[i] && isa<MDNode>(Elements[i]))
560       Elts.push_back(cast<DIType>(Elements[i]));
561     else
562       Elts.push_back(Elements[i]);
563   }
564   return DITypeRefArray(MDNode::get(VMContext, Elts));
565 }
566 
567 DISubrange *DIBuilder::getOrCreateSubrange(int64_t Lo, int64_t Count) {
568   return DISubrange::get(VMContext, Count, Lo);
569 }
570 
571 static void checkGlobalVariableScope(DIScope *Context) {
572 #ifndef NDEBUG
573   if (auto *CT =
574           dyn_cast_or_null<DICompositeType>(getNonCompileUnitScope(Context)))
575     assert(CT->getIdentifier().empty() &&
576            "Context of a global variable should not be a type with identifier");
577 #endif
578 }
579 
580 DIGlobalVariableExpression *DIBuilder::createGlobalVariableExpression(
581     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
582     unsigned LineNumber, DIType *Ty, bool isLocalToUnit, DIExpression *Expr,
583     MDNode *Decl, uint32_t AlignInBits) {
584   checkGlobalVariableScope(Context);
585 
586   auto *GV = DIGlobalVariable::getDistinct(
587       VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
588       LineNumber, Ty, isLocalToUnit, true, cast_or_null<DIDerivedType>(Decl),
589       AlignInBits);
590   auto *N = DIGlobalVariableExpression::get(VMContext, GV, Expr);
591   AllGVs.push_back(N);
592   return N;
593 }
594 
595 DIGlobalVariable *DIBuilder::createTempGlobalVariableFwdDecl(
596     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
597     unsigned LineNumber, DIType *Ty, bool isLocalToUnit, MDNode *Decl,
598     uint32_t AlignInBits) {
599   checkGlobalVariableScope(Context);
600 
601   return DIGlobalVariable::getTemporary(
602              VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
603              LineNumber, Ty, isLocalToUnit, false,
604              cast_or_null<DIDerivedType>(Decl), AlignInBits)
605       .release();
606 }
607 
608 static DILocalVariable *createLocalVariable(
609     LLVMContext &VMContext,
610     DenseMap<MDNode *, SmallVector<TrackingMDNodeRef, 1>> &PreservedVariables,
611     DIScope *Scope, StringRef Name, unsigned ArgNo, DIFile *File,
612     unsigned LineNo, DIType *Ty, bool AlwaysPreserve, DINode::DIFlags Flags,
613     uint32_t AlignInBits) {
614   // FIXME: Why getNonCompileUnitScope()?
615   // FIXME: Why is "!Context" okay here?
616   // FIXME: Why doesn't this check for a subprogram or lexical block (AFAICT
617   // the only valid scopes)?
618   DIScope *Context = getNonCompileUnitScope(Scope);
619 
620   auto *Node =
621       DILocalVariable::get(VMContext, cast_or_null<DILocalScope>(Context), Name,
622                            File, LineNo, Ty, ArgNo, Flags, AlignInBits);
623   if (AlwaysPreserve) {
624     // The optimizer may remove local variables. If there is an interest
625     // to preserve variable info in such situation then stash it in a
626     // named mdnode.
627     DISubprogram *Fn = getDISubprogram(Scope);
628     assert(Fn && "Missing subprogram for local variable");
629     PreservedVariables[Fn].emplace_back(Node);
630   }
631   return Node;
632 }
633 
634 DILocalVariable *DIBuilder::createAutoVariable(DIScope *Scope, StringRef Name,
635                                                DIFile *File, unsigned LineNo,
636                                                DIType *Ty, bool AlwaysPreserve,
637                                                DINode::DIFlags Flags,
638                                                uint32_t AlignInBits) {
639   return createLocalVariable(VMContext, PreservedVariables, Scope, Name,
640                              /* ArgNo */ 0, File, LineNo, Ty, AlwaysPreserve,
641                              Flags, AlignInBits);
642 }
643 
644 DILocalVariable *DIBuilder::createParameterVariable(
645     DIScope *Scope, StringRef Name, unsigned ArgNo, DIFile *File,
646     unsigned LineNo, DIType *Ty, bool AlwaysPreserve, DINode::DIFlags Flags) {
647   assert(ArgNo && "Expected non-zero argument number for parameter");
648   return createLocalVariable(VMContext, PreservedVariables, Scope, Name, ArgNo,
649                              File, LineNo, Ty, AlwaysPreserve, Flags,
650                              /* AlignInBits */0);
651 }
652 
653 DIExpression *DIBuilder::createExpression(ArrayRef<uint64_t> Addr) {
654   return DIExpression::get(VMContext, Addr);
655 }
656 
657 DIExpression *DIBuilder::createExpression(ArrayRef<int64_t> Signed) {
658   // TODO: Remove the callers of this signed version and delete.
659   SmallVector<uint64_t, 8> Addr(Signed.begin(), Signed.end());
660   return createExpression(Addr);
661 }
662 
663 DIExpression *DIBuilder::createFragmentExpression(unsigned OffsetInBytes,
664                                                   unsigned SizeInBytes) {
665   uint64_t Addr[] = {dwarf::DW_OP_LLVM_fragment, OffsetInBytes, SizeInBytes};
666   return DIExpression::get(VMContext, Addr);
667 }
668 
669 template <class... Ts>
670 static DISubprogram *getSubprogram(bool IsDistinct, Ts &&... Args) {
671   if (IsDistinct)
672     return DISubprogram::getDistinct(std::forward<Ts>(Args)...);
673   return DISubprogram::get(std::forward<Ts>(Args)...);
674 }
675 
676 DISubprogram *DIBuilder::createFunction(
677     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
678     unsigned LineNo, DISubroutineType *Ty, bool isLocalToUnit,
679     bool isDefinition, unsigned ScopeLine, DINode::DIFlags Flags,
680     bool isOptimized, DITemplateParameterArray TParams, DISubprogram *Decl,
681     DITypeArray ThrownTypes) {
682   auto *Node = getSubprogram(
683       /* IsDistinct = */ isDefinition, VMContext,
684       getNonCompileUnitScope(Context), Name, LinkageName, File, LineNo, Ty,
685       isLocalToUnit, isDefinition, ScopeLine, nullptr, 0, 0, 0, Flags,
686       isOptimized, isDefinition ? CUNode : nullptr, TParams, Decl,
687       MDTuple::getTemporary(VMContext, None).release(), ThrownTypes);
688 
689   if (isDefinition)
690     AllSubprograms.push_back(Node);
691   trackIfUnresolved(Node);
692   return Node;
693 }
694 
695 DISubprogram *DIBuilder::createTempFunctionFwdDecl(
696     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
697     unsigned LineNo, DISubroutineType *Ty, bool isLocalToUnit,
698     bool isDefinition, unsigned ScopeLine, DINode::DIFlags Flags,
699     bool isOptimized, DITemplateParameterArray TParams, DISubprogram *Decl,
700     DITypeArray ThrownTypes) {
701   return DISubprogram::getTemporary(
702              VMContext, getNonCompileUnitScope(Context), Name, LinkageName,
703              File, LineNo, Ty, isLocalToUnit, isDefinition, ScopeLine, nullptr,
704              0, 0, 0, Flags, isOptimized, isDefinition ? CUNode : nullptr,
705              TParams, Decl, nullptr, ThrownTypes)
706       .release();
707 }
708 
709 DISubprogram *DIBuilder::createMethod(
710     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
711     unsigned LineNo, DISubroutineType *Ty, bool isLocalToUnit,
712     bool isDefinition, unsigned VK, unsigned VIndex, int ThisAdjustment,
713     DIType *VTableHolder, DINode::DIFlags Flags, bool isOptimized,
714     DITemplateParameterArray TParams, DITypeArray ThrownTypes) {
715   assert(getNonCompileUnitScope(Context) &&
716          "Methods should have both a Context and a context that isn't "
717          "the compile unit.");
718   // FIXME: Do we want to use different scope/lines?
719   auto *SP = getSubprogram(
720       /* IsDistinct = */ isDefinition, VMContext, cast<DIScope>(Context), Name,
721       LinkageName, F, LineNo, Ty, isLocalToUnit, isDefinition, LineNo,
722       VTableHolder, VK, VIndex, ThisAdjustment, Flags, isOptimized,
723       isDefinition ? CUNode : nullptr, TParams, nullptr, nullptr, ThrownTypes);
724 
725   if (isDefinition)
726     AllSubprograms.push_back(SP);
727   trackIfUnresolved(SP);
728   return SP;
729 }
730 
731 DINamespace *DIBuilder::createNameSpace(DIScope *Scope, StringRef Name,
732                                         bool ExportSymbols) {
733 
734   // It is okay to *not* make anonymous top-level namespaces distinct, because
735   // all nodes that have an anonymous namespace as their parent scope are
736   // guaranteed to be unique and/or are linked to their containing
737   // DICompileUnit. This decision is an explicit tradeoff of link time versus
738   // memory usage versus code simplicity and may get revisited in the future.
739   return DINamespace::get(VMContext, getNonCompileUnitScope(Scope), Name,
740                           ExportSymbols);
741 }
742 
743 DIModule *DIBuilder::createModule(DIScope *Scope, StringRef Name,
744                                   StringRef ConfigurationMacros,
745                                   StringRef IncludePath,
746                                   StringRef ISysRoot) {
747  return DIModule::get(VMContext, getNonCompileUnitScope(Scope), Name,
748                       ConfigurationMacros, IncludePath, ISysRoot);
749 }
750 
751 DILexicalBlockFile *DIBuilder::createLexicalBlockFile(DIScope *Scope,
752                                                       DIFile *File,
753                                                       unsigned Discriminator) {
754   return DILexicalBlockFile::get(VMContext, Scope, File, Discriminator);
755 }
756 
757 DILexicalBlock *DIBuilder::createLexicalBlock(DIScope *Scope, DIFile *File,
758                                               unsigned Line, unsigned Col) {
759   // Make these distinct, to avoid merging two lexical blocks on the same
760   // file/line/column.
761   return DILexicalBlock::getDistinct(VMContext, getNonCompileUnitScope(Scope),
762                                      File, Line, Col);
763 }
764 
765 static Value *getDbgIntrinsicValueImpl(LLVMContext &VMContext, Value *V) {
766   assert(V && "no value passed to dbg intrinsic");
767   return MetadataAsValue::get(VMContext, ValueAsMetadata::get(V));
768 }
769 
770 static Instruction *withDebugLoc(Instruction *I, const DILocation *DL) {
771   I->setDebugLoc(const_cast<DILocation *>(DL));
772   return I;
773 }
774 
775 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
776                                       DIExpression *Expr, const DILocation *DL,
777                                       Instruction *InsertBefore) {
778   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.declare");
779   assert(DL && "Expected debug loc");
780   assert(DL->getScope()->getSubprogram() ==
781              VarInfo->getScope()->getSubprogram() &&
782          "Expected matching subprograms");
783   if (!DeclareFn)
784     DeclareFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_declare);
785 
786   trackIfUnresolved(VarInfo);
787   trackIfUnresolved(Expr);
788   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, Storage),
789                    MetadataAsValue::get(VMContext, VarInfo),
790                    MetadataAsValue::get(VMContext, Expr)};
791   return withDebugLoc(CallInst::Create(DeclareFn, Args, "", InsertBefore), DL);
792 }
793 
794 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
795                                       DIExpression *Expr, const DILocation *DL,
796                                       BasicBlock *InsertAtEnd) {
797   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.declare");
798   assert(DL && "Expected debug loc");
799   assert(DL->getScope()->getSubprogram() ==
800              VarInfo->getScope()->getSubprogram() &&
801          "Expected matching subprograms");
802   if (!DeclareFn)
803     DeclareFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_declare);
804 
805   trackIfUnresolved(VarInfo);
806   trackIfUnresolved(Expr);
807   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, Storage),
808                    MetadataAsValue::get(VMContext, VarInfo),
809                    MetadataAsValue::get(VMContext, Expr)};
810 
811   // If this block already has a terminator then insert this intrinsic
812   // before the terminator.
813   if (TerminatorInst *T = InsertAtEnd->getTerminator())
814     return withDebugLoc(CallInst::Create(DeclareFn, Args, "", T), DL);
815   return withDebugLoc(CallInst::Create(DeclareFn, Args, "", InsertAtEnd), DL);
816 }
817 
818 Instruction *DIBuilder::insertDbgValueIntrinsic(Value *V, uint64_t Offset,
819                                                 DILocalVariable *VarInfo,
820                                                 DIExpression *Expr,
821                                                 const DILocation *DL,
822                                                 Instruction *InsertBefore) {
823   assert(V && "no value passed to dbg.value");
824   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.value");
825   assert(DL && "Expected debug loc");
826   assert(DL->getScope()->getSubprogram() ==
827              VarInfo->getScope()->getSubprogram() &&
828          "Expected matching subprograms");
829   if (!ValueFn)
830     ValueFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_value);
831 
832   trackIfUnresolved(VarInfo);
833   trackIfUnresolved(Expr);
834   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, V),
835                    ConstantInt::get(Type::getInt64Ty(VMContext), Offset),
836                    MetadataAsValue::get(VMContext, VarInfo),
837                    MetadataAsValue::get(VMContext, Expr)};
838   return withDebugLoc(CallInst::Create(ValueFn, Args, "", InsertBefore), DL);
839 }
840 
841 Instruction *DIBuilder::insertDbgValueIntrinsic(Value *V, uint64_t Offset,
842                                                 DILocalVariable *VarInfo,
843                                                 DIExpression *Expr,
844                                                 const DILocation *DL,
845                                                 BasicBlock *InsertAtEnd) {
846   assert(V && "no value passed to dbg.value");
847   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.value");
848   assert(DL && "Expected debug loc");
849   assert(DL->getScope()->getSubprogram() ==
850              VarInfo->getScope()->getSubprogram() &&
851          "Expected matching subprograms");
852   if (!ValueFn)
853     ValueFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_value);
854 
855   trackIfUnresolved(VarInfo);
856   trackIfUnresolved(Expr);
857   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, V),
858                    ConstantInt::get(Type::getInt64Ty(VMContext), Offset),
859                    MetadataAsValue::get(VMContext, VarInfo),
860                    MetadataAsValue::get(VMContext, Expr)};
861 
862   return withDebugLoc(CallInst::Create(ValueFn, Args, "", InsertAtEnd), DL);
863 }
864 
865 void DIBuilder::replaceVTableHolder(DICompositeType *&T,
866                                     DICompositeType *VTableHolder) {
867   {
868     TypedTrackingMDRef<DICompositeType> N(T);
869     N->replaceVTableHolder(VTableHolder);
870     T = N.get();
871   }
872 
873   // If this didn't create a self-reference, just return.
874   if (T != VTableHolder)
875     return;
876 
877   // Look for unresolved operands.  T will drop RAUW support, orphaning any
878   // cycles underneath it.
879   if (T->isResolved())
880     for (const MDOperand &O : T->operands())
881       if (auto *N = dyn_cast_or_null<MDNode>(O))
882         trackIfUnresolved(N);
883 }
884 
885 void DIBuilder::replaceArrays(DICompositeType *&T, DINodeArray Elements,
886                               DINodeArray TParams) {
887   {
888     TypedTrackingMDRef<DICompositeType> N(T);
889     if (Elements)
890       N->replaceElements(Elements);
891     if (TParams)
892       N->replaceTemplateParams(DITemplateParameterArray(TParams));
893     T = N.get();
894   }
895 
896   // If T isn't resolved, there's no problem.
897   if (!T->isResolved())
898     return;
899 
900   // If T is resolved, it may be due to a self-reference cycle.  Track the
901   // arrays explicitly if they're unresolved, or else the cycles will be
902   // orphaned.
903   if (Elements)
904     trackIfUnresolved(Elements.get());
905   if (TParams)
906     trackIfUnresolved(TParams.get());
907 }
908