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 "llvm/IR/IRBuilder.h"
16 #include "LLVMContextImpl.h"
17 #include "llvm/ADT/Optional.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/BinaryFormat/Dwarf.h"
20 #include "llvm/IR/Constants.h"
21 #include "llvm/IR/DebugInfo.h"
22 #include "llvm/IR/IntrinsicInst.h"
23 #include "llvm/IR/Module.h"
24 #include "llvm/Support/Debug.h"
25 
26 using namespace llvm;
27 using namespace llvm::dwarf;
28 
29 cl::opt<bool>
30     UseDbgAddr("use-dbg-addr",
31                llvm::cl::desc("Use llvm.dbg.addr for all local variables"),
32                cl::init(false), cl::Hidden);
33 
34 DIBuilder::DIBuilder(Module &m, bool AllowUnresolvedNodes, DICompileUnit *CU)
35   : M(m), VMContext(M.getContext()), CUNode(CU),
36       DeclareFn(nullptr), ValueFn(nullptr),
37       AllowUnresolvedNodes(AllowUnresolvedNodes) {}
38 
39 void DIBuilder::trackIfUnresolved(MDNode *N) {
40   if (!N)
41     return;
42   if (N->isResolved())
43     return;
44 
45   assert(AllowUnresolvedNodes && "Cannot handle unresolved nodes");
46   UnresolvedNodes.emplace_back(N);
47 }
48 
49 void DIBuilder::finalizeSubprogram(DISubprogram *SP) {
50   MDTuple *Temp = SP->getVariables().get();
51   if (!Temp || !Temp->isTemporary())
52     return;
53 
54   SmallVector<Metadata *, 4> Variables;
55 
56   auto PV = PreservedVariables.find(SP);
57   if (PV != PreservedVariables.end())
58     Variables.append(PV->second.begin(), PV->second.end());
59 
60   DINodeArray AV = getOrCreateArray(Variables);
61   TempMDTuple(Temp)->replaceAllUsesWith(AV.get());
62 }
63 
64 void DIBuilder::finalize() {
65   if (!CUNode) {
66     assert(!AllowUnresolvedNodes &&
67            "creating type nodes without a CU is not supported");
68     return;
69   }
70 
71   CUNode->replaceEnumTypes(MDTuple::get(VMContext, AllEnumTypes));
72 
73   SmallVector<Metadata *, 16> RetainValues;
74   // Declarations and definitions of the same type may be retained. Some
75   // clients RAUW these pairs, leaving duplicates in the retained types
76   // list. Use a set to remove the duplicates while we transform the
77   // TrackingVHs back into Values.
78   SmallPtrSet<Metadata *, 16> RetainSet;
79   for (unsigned I = 0, E = AllRetainTypes.size(); I < E; I++)
80     if (RetainSet.insert(AllRetainTypes[I]).second)
81       RetainValues.push_back(AllRetainTypes[I]);
82 
83   if (!RetainValues.empty())
84     CUNode->replaceRetainedTypes(MDTuple::get(VMContext, RetainValues));
85 
86   DISubprogramArray SPs = MDTuple::get(VMContext, AllSubprograms);
87   for (auto *SP : SPs)
88     finalizeSubprogram(SP);
89   for (auto *N : RetainValues)
90     if (auto *SP = dyn_cast<DISubprogram>(N))
91       finalizeSubprogram(SP);
92 
93   if (!AllGVs.empty())
94     CUNode->replaceGlobalVariables(MDTuple::get(VMContext, AllGVs));
95 
96   if (!AllImportedModules.empty())
97     CUNode->replaceImportedEntities(MDTuple::get(
98         VMContext, SmallVector<Metadata *, 16>(AllImportedModules.begin(),
99                                                AllImportedModules.end())));
100 
101   for (const auto &I : AllMacrosPerParent) {
102     // DIMacroNode's with nullptr parent are DICompileUnit direct children.
103     if (!I.first) {
104       CUNode->replaceMacros(MDTuple::get(VMContext, I.second.getArrayRef()));
105       continue;
106     }
107     // Otherwise, it must be a temporary DIMacroFile that need to be resolved.
108     auto *TMF = cast<DIMacroFile>(I.first);
109     auto *MF = DIMacroFile::get(VMContext, dwarf::DW_MACINFO_start_file,
110                                 TMF->getLine(), TMF->getFile(),
111                                 getOrCreateMacroArray(I.second.getArrayRef()));
112     replaceTemporary(llvm::TempDIMacroNode(TMF), MF);
113   }
114 
115   // Now that all temp nodes have been replaced or deleted, resolve remaining
116   // cycles.
117   for (const auto &N : UnresolvedNodes)
118     if (N && !N->isResolved())
119       N->resolveCycles();
120   UnresolvedNodes.clear();
121 
122   // Can't handle unresolved nodes anymore.
123   AllowUnresolvedNodes = false;
124 }
125 
126 /// If N is compile unit return NULL otherwise return N.
127 static DIScope *getNonCompileUnitScope(DIScope *N) {
128   if (!N || isa<DICompileUnit>(N))
129     return nullptr;
130   return cast<DIScope>(N);
131 }
132 
133 DICompileUnit *DIBuilder::createCompileUnit(
134     unsigned Lang, DIFile *File, StringRef Producer, bool isOptimized,
135     StringRef Flags, unsigned RunTimeVer, StringRef SplitName,
136     DICompileUnit::DebugEmissionKind Kind, uint64_t DWOId,
137     bool SplitDebugInlining, bool DebugInfoForProfiling, bool GnuPubnames) {
138 
139   assert(((Lang <= dwarf::DW_LANG_Fortran08 && Lang >= dwarf::DW_LANG_C89) ||
140           (Lang <= dwarf::DW_LANG_hi_user && Lang >= dwarf::DW_LANG_lo_user)) &&
141          "Invalid Language tag");
142 
143   assert(!CUNode && "Can only make one compile unit per DIBuilder instance");
144   CUNode = DICompileUnit::getDistinct(
145       VMContext, Lang, File, Producer, isOptimized, Flags, RunTimeVer,
146       SplitName, Kind, nullptr, nullptr, nullptr, nullptr, nullptr, DWOId,
147       SplitDebugInlining, DebugInfoForProfiling, GnuPubnames);
148 
149   // Create a named metadata so that it is easier to find cu in a module.
150   NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
151   NMD->addOperand(CUNode);
152   trackIfUnresolved(CUNode);
153   return CUNode;
154 }
155 
156 static DIImportedEntity *
157 createImportedModule(LLVMContext &C, dwarf::Tag Tag, DIScope *Context,
158                      Metadata *NS, DIFile *File, unsigned Line, StringRef Name,
159                      SmallVectorImpl<TrackingMDNodeRef> &AllImportedModules) {
160   if (Line)
161     assert(File && "Source location has line number but no file");
162   unsigned EntitiesCount = C.pImpl->DIImportedEntitys.size();
163   auto *M =
164       DIImportedEntity::get(C, Tag, Context, DINodeRef(NS), File, Line, Name);
165   if (EntitiesCount < C.pImpl->DIImportedEntitys.size())
166     // A new Imported Entity was just added to the context.
167     // Add it to the Imported Modules list.
168     AllImportedModules.emplace_back(M);
169   return M;
170 }
171 
172 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
173                                                   DINamespace *NS, DIFile *File,
174                                                   unsigned Line) {
175   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
176                                 Context, NS, File, Line, StringRef(),
177                                 AllImportedModules);
178 }
179 
180 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
181                                                   DIImportedEntity *NS,
182                                                   DIFile *File, unsigned Line) {
183   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
184                                 Context, NS, File, Line, StringRef(),
185                                 AllImportedModules);
186 }
187 
188 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context, DIModule *M,
189                                                   DIFile *File, unsigned Line) {
190   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
191                                 Context, M, File, Line, StringRef(),
192                                 AllImportedModules);
193 }
194 
195 DIImportedEntity *DIBuilder::createImportedDeclaration(DIScope *Context,
196                                                        DINode *Decl,
197                                                        DIFile *File,
198                                                        unsigned Line,
199                                                        StringRef Name) {
200   // Make sure to use the unique identifier based metadata reference for
201   // types that have one.
202   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_declaration,
203                                 Context, Decl, File, Line, Name,
204                                 AllImportedModules);
205 }
206 
207 DIFile *DIBuilder::createFile(StringRef Filename, StringRef Directory,
208                               Optional<DIFile::ChecksumInfo<StringRef>> CS,
209                               Optional<StringRef> Source) {
210   return DIFile::get(VMContext, Filename, Directory, CS, Source);
211 }
212 
213 DIMacro *DIBuilder::createMacro(DIMacroFile *Parent, unsigned LineNumber,
214                                 unsigned MacroType, StringRef Name,
215                                 StringRef Value) {
216   assert(!Name.empty() && "Unable to create macro without name");
217   assert((MacroType == dwarf::DW_MACINFO_undef ||
218           MacroType == dwarf::DW_MACINFO_define) &&
219          "Unexpected macro type");
220   auto *M = DIMacro::get(VMContext, MacroType, LineNumber, Name, Value);
221   AllMacrosPerParent[Parent].insert(M);
222   return M;
223 }
224 
225 DIMacroFile *DIBuilder::createTempMacroFile(DIMacroFile *Parent,
226                                             unsigned LineNumber, DIFile *File) {
227   auto *MF = DIMacroFile::getTemporary(VMContext, dwarf::DW_MACINFO_start_file,
228                                        LineNumber, File, DIMacroNodeArray())
229                  .release();
230   AllMacrosPerParent[Parent].insert(MF);
231   // Add the new temporary DIMacroFile to the macro per parent map as a parent.
232   // This is needed to assure DIMacroFile with no children to have an entry in
233   // the map. Otherwise, it will not be resolved in DIBuilder::finalize().
234   AllMacrosPerParent.insert({MF, {}});
235   return MF;
236 }
237 
238 DIEnumerator *DIBuilder::createEnumerator(StringRef Name, int64_t Val,
239                                           bool IsUnsigned) {
240   assert(!Name.empty() && "Unable to create enumerator without name");
241   return DIEnumerator::get(VMContext, Val, IsUnsigned, Name);
242 }
243 
244 DIBasicType *DIBuilder::createUnspecifiedType(StringRef Name) {
245   assert(!Name.empty() && "Unable to create type without name");
246   return DIBasicType::get(VMContext, dwarf::DW_TAG_unspecified_type, Name);
247 }
248 
249 DIBasicType *DIBuilder::createNullPtrType() {
250   return createUnspecifiedType("decltype(nullptr)");
251 }
252 
253 DIBasicType *DIBuilder::createBasicType(StringRef Name, uint64_t SizeInBits,
254                                         unsigned Encoding) {
255   assert(!Name.empty() && "Unable to create type without name");
256   return DIBasicType::get(VMContext, dwarf::DW_TAG_base_type, Name, SizeInBits,
257                           0, Encoding);
258 }
259 
260 DIDerivedType *DIBuilder::createQualifiedType(unsigned Tag, DIType *FromTy) {
261   return DIDerivedType::get(VMContext, Tag, "", nullptr, 0, nullptr, FromTy, 0,
262                             0, 0, None, DINode::FlagZero);
263 }
264 
265 DIDerivedType *DIBuilder::createPointerType(
266     DIType *PointeeTy,
267     uint64_t SizeInBits,
268     uint32_t AlignInBits,
269     Optional<unsigned> DWARFAddressSpace,
270     StringRef Name) {
271   // FIXME: Why is there a name here?
272   return DIDerivedType::get(VMContext, dwarf::DW_TAG_pointer_type, Name,
273                             nullptr, 0, nullptr, PointeeTy, SizeInBits,
274                             AlignInBits, 0, DWARFAddressSpace,
275                             DINode::FlagZero);
276 }
277 
278 DIDerivedType *DIBuilder::createMemberPointerType(DIType *PointeeTy,
279                                                   DIType *Base,
280                                                   uint64_t SizeInBits,
281                                                   uint32_t AlignInBits,
282                                                   DINode::DIFlags Flags) {
283   return DIDerivedType::get(VMContext, dwarf::DW_TAG_ptr_to_member_type, "",
284                             nullptr, 0, nullptr, PointeeTy, SizeInBits,
285                             AlignInBits, 0, None, Flags, Base);
286 }
287 
288 DIDerivedType *DIBuilder::createReferenceType(
289     unsigned Tag, DIType *RTy,
290     uint64_t SizeInBits,
291     uint32_t AlignInBits,
292     Optional<unsigned> DWARFAddressSpace) {
293   assert(RTy && "Unable to create reference type");
294   return DIDerivedType::get(VMContext, Tag, "", nullptr, 0, nullptr, RTy,
295                             SizeInBits, AlignInBits, 0, DWARFAddressSpace,
296                             DINode::FlagZero);
297 }
298 
299 DIDerivedType *DIBuilder::createTypedef(DIType *Ty, StringRef Name,
300                                         DIFile *File, unsigned LineNo,
301                                         DIScope *Context) {
302   return DIDerivedType::get(VMContext, dwarf::DW_TAG_typedef, Name, File,
303                             LineNo, getNonCompileUnitScope(Context), Ty, 0, 0,
304                             0, None, DINode::FlagZero);
305 }
306 
307 DIDerivedType *DIBuilder::createFriend(DIType *Ty, DIType *FriendTy) {
308   assert(Ty && "Invalid type!");
309   assert(FriendTy && "Invalid friend type!");
310   return DIDerivedType::get(VMContext, dwarf::DW_TAG_friend, "", nullptr, 0, Ty,
311                             FriendTy, 0, 0, 0, None, DINode::FlagZero);
312 }
313 
314 DIDerivedType *DIBuilder::createInheritance(DIType *Ty, DIType *BaseTy,
315                                             uint64_t BaseOffset,
316                                             DINode::DIFlags Flags) {
317   assert(Ty && "Unable to create inheritance");
318   return DIDerivedType::get(VMContext, dwarf::DW_TAG_inheritance, "", nullptr,
319                             0, Ty, BaseTy, 0, 0, BaseOffset, None, Flags);
320 }
321 
322 DIDerivedType *DIBuilder::createMemberType(DIScope *Scope, StringRef Name,
323                                            DIFile *File, unsigned LineNumber,
324                                            uint64_t SizeInBits,
325                                            uint32_t AlignInBits,
326                                            uint64_t OffsetInBits,
327                                            DINode::DIFlags Flags, DIType *Ty) {
328   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
329                             LineNumber, getNonCompileUnitScope(Scope), Ty,
330                             SizeInBits, AlignInBits, OffsetInBits, None, Flags);
331 }
332 
333 static ConstantAsMetadata *getConstantOrNull(Constant *C) {
334   if (C)
335     return ConstantAsMetadata::get(C);
336   return nullptr;
337 }
338 
339 DIDerivedType *DIBuilder::createVariantMemberType(DIScope *Scope, StringRef Name,
340 						  DIFile *File, unsigned LineNumber,
341 						  uint64_t SizeInBits,
342 						  uint32_t AlignInBits,
343 						  uint64_t OffsetInBits,
344 						  Constant *Discriminant,
345 						  DINode::DIFlags Flags, DIType *Ty) {
346   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
347                             LineNumber, getNonCompileUnitScope(Scope), Ty,
348                             SizeInBits, AlignInBits, OffsetInBits, None, Flags,
349                             getConstantOrNull(Discriminant));
350 }
351 
352 DIDerivedType *DIBuilder::createBitFieldMemberType(
353     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
354     uint64_t SizeInBits, uint64_t OffsetInBits, uint64_t StorageOffsetInBits,
355     DINode::DIFlags Flags, DIType *Ty) {
356   Flags |= DINode::FlagBitField;
357   return DIDerivedType::get(
358       VMContext, dwarf::DW_TAG_member, Name, File, LineNumber,
359       getNonCompileUnitScope(Scope), Ty, SizeInBits, /* AlignInBits */ 0,
360       OffsetInBits, None, Flags,
361       ConstantAsMetadata::get(ConstantInt::get(IntegerType::get(VMContext, 64),
362                                                StorageOffsetInBits)));
363 }
364 
365 DIDerivedType *
366 DIBuilder::createStaticMemberType(DIScope *Scope, StringRef Name, DIFile *File,
367                                   unsigned LineNumber, DIType *Ty,
368                                   DINode::DIFlags Flags, llvm::Constant *Val,
369                                   uint32_t AlignInBits) {
370   Flags |= DINode::FlagStaticMember;
371   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
372                             LineNumber, getNonCompileUnitScope(Scope), Ty, 0,
373                             AlignInBits, 0, None, Flags,
374                             getConstantOrNull(Val));
375 }
376 
377 DIDerivedType *
378 DIBuilder::createObjCIVar(StringRef Name, DIFile *File, unsigned LineNumber,
379                           uint64_t SizeInBits, uint32_t AlignInBits,
380                           uint64_t OffsetInBits, DINode::DIFlags Flags,
381                           DIType *Ty, MDNode *PropertyNode) {
382   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
383                             LineNumber, getNonCompileUnitScope(File), Ty,
384                             SizeInBits, AlignInBits, OffsetInBits, None, Flags,
385                             PropertyNode);
386 }
387 
388 DIObjCProperty *
389 DIBuilder::createObjCProperty(StringRef Name, DIFile *File, unsigned LineNumber,
390                               StringRef GetterName, StringRef SetterName,
391                               unsigned PropertyAttributes, DIType *Ty) {
392   return DIObjCProperty::get(VMContext, Name, File, LineNumber, GetterName,
393                              SetterName, PropertyAttributes, Ty);
394 }
395 
396 DITemplateTypeParameter *
397 DIBuilder::createTemplateTypeParameter(DIScope *Context, StringRef Name,
398                                        DIType *Ty) {
399   assert((!Context || isa<DICompileUnit>(Context)) && "Expected compile unit");
400   return DITemplateTypeParameter::get(VMContext, Name, Ty);
401 }
402 
403 static DITemplateValueParameter *
404 createTemplateValueParameterHelper(LLVMContext &VMContext, unsigned Tag,
405                                    DIScope *Context, StringRef Name, DIType *Ty,
406                                    Metadata *MD) {
407   assert((!Context || isa<DICompileUnit>(Context)) && "Expected compile unit");
408   return DITemplateValueParameter::get(VMContext, Tag, Name, Ty, MD);
409 }
410 
411 DITemplateValueParameter *
412 DIBuilder::createTemplateValueParameter(DIScope *Context, StringRef Name,
413                                         DIType *Ty, Constant *Val) {
414   return createTemplateValueParameterHelper(
415       VMContext, dwarf::DW_TAG_template_value_parameter, Context, Name, Ty,
416       getConstantOrNull(Val));
417 }
418 
419 DITemplateValueParameter *
420 DIBuilder::createTemplateTemplateParameter(DIScope *Context, StringRef Name,
421                                            DIType *Ty, StringRef Val) {
422   return createTemplateValueParameterHelper(
423       VMContext, dwarf::DW_TAG_GNU_template_template_param, Context, Name, Ty,
424       MDString::get(VMContext, Val));
425 }
426 
427 DITemplateValueParameter *
428 DIBuilder::createTemplateParameterPack(DIScope *Context, StringRef Name,
429                                        DIType *Ty, DINodeArray Val) {
430   return createTemplateValueParameterHelper(
431       VMContext, dwarf::DW_TAG_GNU_template_parameter_pack, Context, Name, Ty,
432       Val.get());
433 }
434 
435 DICompositeType *DIBuilder::createClassType(
436     DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
437     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
438     DINode::DIFlags Flags, DIType *DerivedFrom, DINodeArray Elements,
439     DIType *VTableHolder, MDNode *TemplateParams, StringRef UniqueIdentifier) {
440   assert((!Context || isa<DIScope>(Context)) &&
441          "createClassType should be called with a valid Context");
442 
443   auto *R = DICompositeType::get(
444       VMContext, dwarf::DW_TAG_structure_type, Name, File, LineNumber,
445       getNonCompileUnitScope(Context), DerivedFrom, SizeInBits, AlignInBits,
446       OffsetInBits, Flags, Elements, 0, VTableHolder,
447       cast_or_null<MDTuple>(TemplateParams), UniqueIdentifier);
448   trackIfUnresolved(R);
449   return R;
450 }
451 
452 DICompositeType *DIBuilder::createStructType(
453     DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
454     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
455     DIType *DerivedFrom, DINodeArray Elements, unsigned RunTimeLang,
456     DIType *VTableHolder, StringRef UniqueIdentifier) {
457   auto *R = DICompositeType::get(
458       VMContext, dwarf::DW_TAG_structure_type, Name, File, LineNumber,
459       getNonCompileUnitScope(Context), DerivedFrom, SizeInBits, AlignInBits, 0,
460       Flags, Elements, RunTimeLang, VTableHolder, nullptr, UniqueIdentifier);
461   trackIfUnresolved(R);
462   return R;
463 }
464 
465 DICompositeType *DIBuilder::createUnionType(
466     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
467     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
468     DINodeArray Elements, unsigned RunTimeLang, StringRef UniqueIdentifier) {
469   auto *R = DICompositeType::get(
470       VMContext, dwarf::DW_TAG_union_type, Name, File, LineNumber,
471       getNonCompileUnitScope(Scope), nullptr, SizeInBits, AlignInBits, 0, Flags,
472       Elements, RunTimeLang, nullptr, nullptr, UniqueIdentifier);
473   trackIfUnresolved(R);
474   return R;
475 }
476 
477 DICompositeType *DIBuilder::createVariantPart(
478     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
479     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
480     DIDerivedType *Discriminator, DINodeArray Elements, StringRef UniqueIdentifier) {
481   auto *R = DICompositeType::get(
482       VMContext, dwarf::DW_TAG_variant_part, Name, File, LineNumber,
483       getNonCompileUnitScope(Scope), nullptr, SizeInBits, AlignInBits, 0, Flags,
484       Elements, 0, nullptr, nullptr, UniqueIdentifier, Discriminator);
485   trackIfUnresolved(R);
486   return R;
487 }
488 
489 DISubroutineType *DIBuilder::createSubroutineType(DITypeRefArray ParameterTypes,
490                                                   DINode::DIFlags Flags,
491                                                   unsigned CC) {
492   return DISubroutineType::get(VMContext, Flags, CC, ParameterTypes);
493 }
494 
495 DICompositeType *DIBuilder::createEnumerationType(
496     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
497     uint64_t SizeInBits, uint32_t AlignInBits, DINodeArray Elements,
498     DIType *UnderlyingType, StringRef UniqueIdentifier, bool IsFixed) {
499   auto *CTy = DICompositeType::get(
500       VMContext, dwarf::DW_TAG_enumeration_type, Name, File, LineNumber,
501       getNonCompileUnitScope(Scope), UnderlyingType, SizeInBits, AlignInBits, 0,
502       IsFixed ? DINode::FlagFixedEnum : DINode::FlagZero, Elements, 0, nullptr,
503       nullptr, UniqueIdentifier);
504   AllEnumTypes.push_back(CTy);
505   trackIfUnresolved(CTy);
506   return CTy;
507 }
508 
509 DICompositeType *DIBuilder::createArrayType(uint64_t Size,
510                                             uint32_t AlignInBits, DIType *Ty,
511                                             DINodeArray Subscripts) {
512   auto *R = DICompositeType::get(VMContext, dwarf::DW_TAG_array_type, "",
513                                  nullptr, 0, nullptr, Ty, Size, AlignInBits, 0,
514                                  DINode::FlagZero, Subscripts, 0, nullptr);
515   trackIfUnresolved(R);
516   return R;
517 }
518 
519 DICompositeType *DIBuilder::createVectorType(uint64_t Size,
520                                              uint32_t AlignInBits, DIType *Ty,
521                                              DINodeArray Subscripts) {
522   auto *R = DICompositeType::get(VMContext, dwarf::DW_TAG_array_type, "",
523                                  nullptr, 0, nullptr, Ty, Size, AlignInBits, 0,
524                                  DINode::FlagVector, Subscripts, 0, nullptr);
525   trackIfUnresolved(R);
526   return R;
527 }
528 
529 static DIType *createTypeWithFlags(LLVMContext &Context, DIType *Ty,
530                                    DINode::DIFlags FlagsToSet) {
531   auto NewTy = Ty->clone();
532   NewTy->setFlags(NewTy->getFlags() | FlagsToSet);
533   return MDNode::replaceWithUniqued(std::move(NewTy));
534 }
535 
536 DIType *DIBuilder::createArtificialType(DIType *Ty) {
537   // FIXME: Restrict this to the nodes where it's valid.
538   if (Ty->isArtificial())
539     return Ty;
540   return createTypeWithFlags(VMContext, Ty, DINode::FlagArtificial);
541 }
542 
543 DIType *DIBuilder::createObjectPointerType(DIType *Ty) {
544   // FIXME: Restrict this to the nodes where it's valid.
545   if (Ty->isObjectPointer())
546     return Ty;
547   DINode::DIFlags Flags = DINode::FlagObjectPointer | DINode::FlagArtificial;
548   return createTypeWithFlags(VMContext, Ty, Flags);
549 }
550 
551 void DIBuilder::retainType(DIScope *T) {
552   assert(T && "Expected non-null type");
553   assert((isa<DIType>(T) || (isa<DISubprogram>(T) &&
554                              cast<DISubprogram>(T)->isDefinition() == false)) &&
555          "Expected type or subprogram declaration");
556   AllRetainTypes.emplace_back(T);
557 }
558 
559 DIBasicType *DIBuilder::createUnspecifiedParameter() { return nullptr; }
560 
561 DICompositeType *
562 DIBuilder::createForwardDecl(unsigned Tag, StringRef Name, DIScope *Scope,
563                              DIFile *F, unsigned Line, unsigned RuntimeLang,
564                              uint64_t SizeInBits, uint32_t AlignInBits,
565                              StringRef UniqueIdentifier) {
566   // FIXME: Define in terms of createReplaceableForwardDecl() by calling
567   // replaceWithUniqued().
568   auto *RetTy = DICompositeType::get(
569       VMContext, Tag, Name, F, Line, getNonCompileUnitScope(Scope), nullptr,
570       SizeInBits, AlignInBits, 0, DINode::FlagFwdDecl, nullptr, RuntimeLang,
571       nullptr, nullptr, UniqueIdentifier);
572   trackIfUnresolved(RetTy);
573   return RetTy;
574 }
575 
576 DICompositeType *DIBuilder::createReplaceableCompositeType(
577     unsigned Tag, StringRef Name, DIScope *Scope, DIFile *F, unsigned Line,
578     unsigned RuntimeLang, uint64_t SizeInBits, uint32_t AlignInBits,
579     DINode::DIFlags Flags, StringRef UniqueIdentifier) {
580   auto *RetTy =
581       DICompositeType::getTemporary(
582           VMContext, Tag, Name, F, Line, getNonCompileUnitScope(Scope), nullptr,
583           SizeInBits, AlignInBits, 0, Flags, nullptr, RuntimeLang, nullptr,
584           nullptr, UniqueIdentifier)
585           .release();
586   trackIfUnresolved(RetTy);
587   return RetTy;
588 }
589 
590 DINodeArray DIBuilder::getOrCreateArray(ArrayRef<Metadata *> Elements) {
591   return MDTuple::get(VMContext, Elements);
592 }
593 
594 DIMacroNodeArray
595 DIBuilder::getOrCreateMacroArray(ArrayRef<Metadata *> Elements) {
596   return MDTuple::get(VMContext, Elements);
597 }
598 
599 DITypeRefArray DIBuilder::getOrCreateTypeArray(ArrayRef<Metadata *> Elements) {
600   SmallVector<llvm::Metadata *, 16> Elts;
601   for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
602     if (Elements[i] && isa<MDNode>(Elements[i]))
603       Elts.push_back(cast<DIType>(Elements[i]));
604     else
605       Elts.push_back(Elements[i]);
606   }
607   return DITypeRefArray(MDNode::get(VMContext, Elts));
608 }
609 
610 DISubrange *DIBuilder::getOrCreateSubrange(int64_t Lo, int64_t Count) {
611   return DISubrange::get(VMContext, Count, Lo);
612 }
613 
614 DISubrange *DIBuilder::getOrCreateSubrange(int64_t Lo, Metadata *CountNode) {
615   return DISubrange::get(VMContext, CountNode, Lo);
616 }
617 
618 static void checkGlobalVariableScope(DIScope *Context) {
619 #ifndef NDEBUG
620   if (auto *CT =
621           dyn_cast_or_null<DICompositeType>(getNonCompileUnitScope(Context)))
622     assert(CT->getIdentifier().empty() &&
623            "Context of a global variable should not be a type with identifier");
624 #endif
625 }
626 
627 DIGlobalVariableExpression *DIBuilder::createGlobalVariableExpression(
628     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
629     unsigned LineNumber, DIType *Ty, bool isLocalToUnit, DIExpression *Expr,
630     MDNode *Decl, uint32_t AlignInBits) {
631   checkGlobalVariableScope(Context);
632 
633   auto *GV = DIGlobalVariable::getDistinct(
634       VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
635       LineNumber, Ty, isLocalToUnit, true, cast_or_null<DIDerivedType>(Decl),
636       AlignInBits);
637   if (!Expr)
638     Expr = createExpression();
639   auto *N = DIGlobalVariableExpression::get(VMContext, GV, Expr);
640   AllGVs.push_back(N);
641   return N;
642 }
643 
644 DIGlobalVariable *DIBuilder::createTempGlobalVariableFwdDecl(
645     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
646     unsigned LineNumber, DIType *Ty, bool isLocalToUnit, MDNode *Decl,
647     uint32_t AlignInBits) {
648   checkGlobalVariableScope(Context);
649 
650   return DIGlobalVariable::getTemporary(
651              VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
652              LineNumber, Ty, isLocalToUnit, false,
653              cast_or_null<DIDerivedType>(Decl), AlignInBits)
654       .release();
655 }
656 
657 static DILocalVariable *createLocalVariable(
658     LLVMContext &VMContext,
659     DenseMap<MDNode *, SmallVector<TrackingMDNodeRef, 1>> &PreservedVariables,
660     DIScope *Scope, StringRef Name, unsigned ArgNo, DIFile *File,
661     unsigned LineNo, DIType *Ty, bool AlwaysPreserve, DINode::DIFlags Flags,
662     uint32_t AlignInBits) {
663   // FIXME: Why getNonCompileUnitScope()?
664   // FIXME: Why is "!Context" okay here?
665   // FIXME: Why doesn't this check for a subprogram or lexical block (AFAICT
666   // the only valid scopes)?
667   DIScope *Context = getNonCompileUnitScope(Scope);
668 
669   auto *Node =
670       DILocalVariable::get(VMContext, cast_or_null<DILocalScope>(Context), Name,
671                            File, LineNo, Ty, ArgNo, Flags, AlignInBits);
672   if (AlwaysPreserve) {
673     // The optimizer may remove local variables. If there is an interest
674     // to preserve variable info in such situation then stash it in a
675     // named mdnode.
676     DISubprogram *Fn = getDISubprogram(Scope);
677     assert(Fn && "Missing subprogram for local variable");
678     PreservedVariables[Fn].emplace_back(Node);
679   }
680   return Node;
681 }
682 
683 DILocalVariable *DIBuilder::createAutoVariable(DIScope *Scope, StringRef Name,
684                                                DIFile *File, unsigned LineNo,
685                                                DIType *Ty, bool AlwaysPreserve,
686                                                DINode::DIFlags Flags,
687                                                uint32_t AlignInBits) {
688   return createLocalVariable(VMContext, PreservedVariables, Scope, Name,
689                              /* ArgNo */ 0, File, LineNo, Ty, AlwaysPreserve,
690                              Flags, AlignInBits);
691 }
692 
693 DILocalVariable *DIBuilder::createParameterVariable(
694     DIScope *Scope, StringRef Name, unsigned ArgNo, DIFile *File,
695     unsigned LineNo, DIType *Ty, bool AlwaysPreserve, DINode::DIFlags Flags) {
696   assert(ArgNo && "Expected non-zero argument number for parameter");
697   return createLocalVariable(VMContext, PreservedVariables, Scope, Name, ArgNo,
698                              File, LineNo, Ty, AlwaysPreserve, Flags,
699                              /* AlignInBits */0);
700 }
701 
702 DIExpression *DIBuilder::createExpression(ArrayRef<uint64_t> Addr) {
703   return DIExpression::get(VMContext, Addr);
704 }
705 
706 DIExpression *DIBuilder::createExpression(ArrayRef<int64_t> Signed) {
707   // TODO: Remove the callers of this signed version and delete.
708   SmallVector<uint64_t, 8> Addr(Signed.begin(), Signed.end());
709   return createExpression(Addr);
710 }
711 
712 template <class... Ts>
713 static DISubprogram *getSubprogram(bool IsDistinct, Ts &&... Args) {
714   if (IsDistinct)
715     return DISubprogram::getDistinct(std::forward<Ts>(Args)...);
716   return DISubprogram::get(std::forward<Ts>(Args)...);
717 }
718 
719 DISubprogram *DIBuilder::createFunction(
720     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
721     unsigned LineNo, DISubroutineType *Ty, bool isLocalToUnit,
722     bool isDefinition, unsigned ScopeLine, DINode::DIFlags Flags,
723     bool isOptimized, DITemplateParameterArray TParams, DISubprogram *Decl,
724     DITypeArray ThrownTypes) {
725   auto *Node = getSubprogram(
726       /* IsDistinct = */ isDefinition, VMContext,
727       getNonCompileUnitScope(Context), Name, LinkageName, File, LineNo, Ty,
728       isLocalToUnit, isDefinition, ScopeLine, nullptr, 0, 0, 0, Flags,
729       isOptimized, isDefinition ? CUNode : nullptr, TParams, Decl,
730       MDTuple::getTemporary(VMContext, None).release(), ThrownTypes);
731 
732   if (isDefinition)
733     AllSubprograms.push_back(Node);
734   trackIfUnresolved(Node);
735   return Node;
736 }
737 
738 DISubprogram *DIBuilder::createTempFunctionFwdDecl(
739     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
740     unsigned LineNo, DISubroutineType *Ty, bool isLocalToUnit,
741     bool isDefinition, unsigned ScopeLine, DINode::DIFlags Flags,
742     bool isOptimized, DITemplateParameterArray TParams, DISubprogram *Decl,
743     DITypeArray ThrownTypes) {
744   return DISubprogram::getTemporary(
745              VMContext, getNonCompileUnitScope(Context), Name, LinkageName,
746              File, LineNo, Ty, isLocalToUnit, isDefinition, ScopeLine, nullptr,
747              0, 0, 0, Flags, isOptimized, isDefinition ? CUNode : nullptr,
748              TParams, Decl, nullptr, ThrownTypes)
749       .release();
750 }
751 
752 DISubprogram *DIBuilder::createMethod(
753     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
754     unsigned LineNo, DISubroutineType *Ty, bool isLocalToUnit,
755     bool isDefinition, unsigned VK, unsigned VIndex, int ThisAdjustment,
756     DIType *VTableHolder, DINode::DIFlags Flags, bool isOptimized,
757     DITemplateParameterArray TParams, DITypeArray ThrownTypes) {
758   assert(getNonCompileUnitScope(Context) &&
759          "Methods should have both a Context and a context that isn't "
760          "the compile unit.");
761   // FIXME: Do we want to use different scope/lines?
762   auto *SP = getSubprogram(
763       /* IsDistinct = */ isDefinition, VMContext, cast<DIScope>(Context), Name,
764       LinkageName, F, LineNo, Ty, isLocalToUnit, isDefinition, LineNo,
765       VTableHolder, VK, VIndex, ThisAdjustment, Flags, isOptimized,
766       isDefinition ? CUNode : nullptr, TParams, nullptr, nullptr, ThrownTypes);
767 
768   if (isDefinition)
769     AllSubprograms.push_back(SP);
770   trackIfUnresolved(SP);
771   return SP;
772 }
773 
774 DINamespace *DIBuilder::createNameSpace(DIScope *Scope, StringRef Name,
775                                         bool ExportSymbols) {
776 
777   // It is okay to *not* make anonymous top-level namespaces distinct, because
778   // all nodes that have an anonymous namespace as their parent scope are
779   // guaranteed to be unique and/or are linked to their containing
780   // DICompileUnit. This decision is an explicit tradeoff of link time versus
781   // memory usage versus code simplicity and may get revisited in the future.
782   return DINamespace::get(VMContext, getNonCompileUnitScope(Scope), Name,
783                           ExportSymbols);
784 }
785 
786 DIModule *DIBuilder::createModule(DIScope *Scope, StringRef Name,
787                                   StringRef ConfigurationMacros,
788                                   StringRef IncludePath,
789                                   StringRef ISysRoot) {
790  return DIModule::get(VMContext, getNonCompileUnitScope(Scope), Name,
791                       ConfigurationMacros, IncludePath, ISysRoot);
792 }
793 
794 DILexicalBlockFile *DIBuilder::createLexicalBlockFile(DIScope *Scope,
795                                                       DIFile *File,
796                                                       unsigned Discriminator) {
797   return DILexicalBlockFile::get(VMContext, Scope, File, Discriminator);
798 }
799 
800 DILexicalBlock *DIBuilder::createLexicalBlock(DIScope *Scope, DIFile *File,
801                                               unsigned Line, unsigned Col) {
802   // Make these distinct, to avoid merging two lexical blocks on the same
803   // file/line/column.
804   return DILexicalBlock::getDistinct(VMContext, getNonCompileUnitScope(Scope),
805                                      File, Line, Col);
806 }
807 
808 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
809                                       DIExpression *Expr, const DILocation *DL,
810                                       Instruction *InsertBefore) {
811   return insertDeclare(Storage, VarInfo, Expr, DL, InsertBefore->getParent(),
812                        InsertBefore);
813 }
814 
815 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
816                                       DIExpression *Expr, const DILocation *DL,
817                                       BasicBlock *InsertAtEnd) {
818   // If this block already has a terminator then insert this intrinsic before
819   // the terminator. Otherwise, put it at the end of the block.
820   Instruction *InsertBefore = InsertAtEnd->getTerminator();
821   return insertDeclare(Storage, VarInfo, Expr, DL, InsertAtEnd, InsertBefore);
822 }
823 
824 Instruction *DIBuilder::insertDbgValueIntrinsic(Value *V,
825                                                 DILocalVariable *VarInfo,
826                                                 DIExpression *Expr,
827                                                 const DILocation *DL,
828                                                 Instruction *InsertBefore) {
829   return insertDbgValueIntrinsic(
830       V, VarInfo, Expr, DL, InsertBefore ? InsertBefore->getParent() : nullptr,
831       InsertBefore);
832 }
833 
834 Instruction *DIBuilder::insertDbgValueIntrinsic(Value *V,
835                                                 DILocalVariable *VarInfo,
836                                                 DIExpression *Expr,
837                                                 const DILocation *DL,
838                                                 BasicBlock *InsertAtEnd) {
839   return insertDbgValueIntrinsic(V, VarInfo, Expr, DL, InsertAtEnd, nullptr);
840 }
841 
842 /// Return an IRBuilder for inserting dbg.declare and dbg.value intrinsics. This
843 /// abstracts over the various ways to specify an insert position.
844 static IRBuilder<> getIRBForDbgInsertion(const DILocation *DL,
845                                          BasicBlock *InsertBB,
846                                          Instruction *InsertBefore) {
847   IRBuilder<> B(DL->getContext());
848   if (InsertBefore)
849     B.SetInsertPoint(InsertBefore);
850   else if (InsertBB)
851     B.SetInsertPoint(InsertBB);
852   B.SetCurrentDebugLocation(DL);
853   return B;
854 }
855 
856 static Value *getDbgIntrinsicValueImpl(LLVMContext &VMContext, Value *V) {
857   assert(V && "no value passed to dbg intrinsic");
858   return MetadataAsValue::get(VMContext, ValueAsMetadata::get(V));
859 }
860 
861 static Function *getDeclareIntrin(Module &M) {
862   return Intrinsic::getDeclaration(&M, UseDbgAddr ? Intrinsic::dbg_addr
863                                                   : Intrinsic::dbg_declare);
864 }
865 
866 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
867                                       DIExpression *Expr, const DILocation *DL,
868                                       BasicBlock *InsertBB, Instruction *InsertBefore) {
869   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.declare");
870   assert(DL && "Expected debug loc");
871   assert(DL->getScope()->getSubprogram() ==
872              VarInfo->getScope()->getSubprogram() &&
873          "Expected matching subprograms");
874   if (!DeclareFn)
875     DeclareFn = getDeclareIntrin(M);
876 
877   trackIfUnresolved(VarInfo);
878   trackIfUnresolved(Expr);
879   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, Storage),
880                    MetadataAsValue::get(VMContext, VarInfo),
881                    MetadataAsValue::get(VMContext, Expr)};
882 
883   IRBuilder<> B = getIRBForDbgInsertion(DL, InsertBB, InsertBefore);
884   return B.CreateCall(DeclareFn, Args);
885 }
886 
887 Instruction *DIBuilder::insertDbgValueIntrinsic(
888     Value *V, DILocalVariable *VarInfo, DIExpression *Expr,
889     const DILocation *DL, BasicBlock *InsertBB, Instruction *InsertBefore) {
890   assert(V && "no value passed to dbg.value");
891   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.value");
892   assert(DL && "Expected debug loc");
893   assert(DL->getScope()->getSubprogram() ==
894              VarInfo->getScope()->getSubprogram() &&
895          "Expected matching subprograms");
896   if (!ValueFn)
897     ValueFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_value);
898 
899   trackIfUnresolved(VarInfo);
900   trackIfUnresolved(Expr);
901   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, V),
902                    MetadataAsValue::get(VMContext, VarInfo),
903                    MetadataAsValue::get(VMContext, Expr)};
904 
905   IRBuilder<> B = getIRBForDbgInsertion(DL, InsertBB, InsertBefore);
906   return B.CreateCall(ValueFn, Args);
907 }
908 
909 void DIBuilder::replaceVTableHolder(DICompositeType *&T,
910                                     DIType *VTableHolder) {
911   {
912     TypedTrackingMDRef<DICompositeType> N(T);
913     N->replaceVTableHolder(VTableHolder);
914     T = N.get();
915   }
916 
917   // If this didn't create a self-reference, just return.
918   if (T != VTableHolder)
919     return;
920 
921   // Look for unresolved operands.  T will drop RAUW support, orphaning any
922   // cycles underneath it.
923   if (T->isResolved())
924     for (const MDOperand &O : T->operands())
925       if (auto *N = dyn_cast_or_null<MDNode>(O))
926         trackIfUnresolved(N);
927 }
928 
929 void DIBuilder::replaceArrays(DICompositeType *&T, DINodeArray Elements,
930                               DINodeArray TParams) {
931   {
932     TypedTrackingMDRef<DICompositeType> N(T);
933     if (Elements)
934       N->replaceElements(Elements);
935     if (TParams)
936       N->replaceTemplateParams(DITemplateParameterArray(TParams));
937     T = N.get();
938   }
939 
940   // If T isn't resolved, there's no problem.
941   if (!T->isResolved())
942     return;
943 
944   // If T is resolved, it may be due to a self-reference cycle.  Track the
945   // arrays explicitly if they're unresolved, or else the cycles will be
946   // orphaned.
947   if (Elements)
948     trackIfUnresolved(Elements.get());
949   if (TParams)
950     trackIfUnresolved(TParams.get());
951 }
952