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/ADT/STLExtras.h"
16 #include "llvm/IR/Constants.h"
17 #include "llvm/IR/DebugInfo.h"
18 #include "llvm/IR/IntrinsicInst.h"
19 #include "llvm/IR/Module.h"
20 #include "llvm/Support/Debug.h"
21 #include "llvm/Support/Dwarf.h"
22 #include "LLVMContextImpl.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::finalize() {
43   if (!CUNode) {
44     assert(!AllowUnresolvedNodes &&
45            "creating type nodes without a CU is not supported");
46     return;
47   }
48 
49   CUNode->replaceEnumTypes(MDTuple::get(VMContext, AllEnumTypes));
50 
51   SmallVector<Metadata *, 16> RetainValues;
52   // Declarations and definitions of the same type may be retained. Some
53   // clients RAUW these pairs, leaving duplicates in the retained types
54   // list. Use a set to remove the duplicates while we transform the
55   // TrackingVHs back into Values.
56   SmallPtrSet<Metadata *, 16> RetainSet;
57   for (unsigned I = 0, E = AllRetainTypes.size(); I < E; I++)
58     if (RetainSet.insert(AllRetainTypes[I]).second)
59       RetainValues.push_back(AllRetainTypes[I]);
60 
61   if (!RetainValues.empty())
62     CUNode->replaceRetainedTypes(MDTuple::get(VMContext, RetainValues));
63 
64   DISubprogramArray SPs = MDTuple::get(VMContext, AllSubprograms);
65   auto resolveVariables = [&](DISubprogram *SP) {
66     MDTuple *Temp = SP->getVariables().get();
67     if (!Temp)
68       return;
69 
70     SmallVector<Metadata *, 4> Variables;
71 
72     auto PV = PreservedVariables.find(SP);
73     if (PV != PreservedVariables.end())
74       Variables.append(PV->second.begin(), PV->second.end());
75 
76     DINodeArray AV = getOrCreateArray(Variables);
77     TempMDTuple(Temp)->replaceAllUsesWith(AV.get());
78   };
79   for (auto *SP : SPs)
80     resolveVariables(SP);
81   for (auto *N : RetainValues)
82     if (auto *SP = dyn_cast<DISubprogram>(N))
83       resolveVariables(SP);
84 
85   if (!AllGVs.empty())
86     CUNode->replaceGlobalVariables(MDTuple::get(VMContext, AllGVs));
87 
88   if (!AllImportedModules.empty())
89     CUNode->replaceImportedEntities(MDTuple::get(
90         VMContext, SmallVector<Metadata *, 16>(AllImportedModules.begin(),
91                                                AllImportedModules.end())));
92 
93   for (const auto &I : AllMacrosPerParent) {
94     // DIMacroNode's with nullptr parent are DICompileUnit direct children.
95     if (!I.first) {
96       CUNode->replaceMacros(MDTuple::get(VMContext, I.second.getArrayRef()));
97       continue;
98     }
99     // Otherwise, it must be a temporary DIMacroFile that need to be resolved.
100     auto *TMF = cast<DIMacroFile>(I.first);
101     auto *MF = DIMacroFile::get(VMContext, dwarf::DW_MACINFO_start_file,
102                                 TMF->getLine(), TMF->getFile(),
103                                 getOrCreateMacroArray(I.second.getArrayRef()));
104     replaceTemporary(llvm::TempDIMacroNode(TMF), MF);
105   }
106 
107   // Now that all temp nodes have been replaced or deleted, resolve remaining
108   // cycles.
109   for (const auto &N : UnresolvedNodes)
110     if (N && !N->isResolved())
111       N->resolveCycles();
112   UnresolvedNodes.clear();
113 
114   // Can't handle unresolved nodes anymore.
115   AllowUnresolvedNodes = false;
116 }
117 
118 /// If N is compile unit return NULL otherwise return N.
119 static DIScope *getNonCompileUnitScope(DIScope *N) {
120   if (!N || isa<DICompileUnit>(N))
121     return nullptr;
122   return cast<DIScope>(N);
123 }
124 
125 DICompileUnit *DIBuilder::createCompileUnit(
126     unsigned Lang, DIFile *File, StringRef Producer, bool isOptimized,
127     StringRef Flags, unsigned RunTimeVer, StringRef SplitName,
128     DICompileUnit::DebugEmissionKind Kind, uint64_t DWOId,
129     bool SplitDebugInlining, bool DebugInfoForProfiling) {
130 
131   assert(((Lang <= dwarf::DW_LANG_Fortran08 && Lang >= dwarf::DW_LANG_C89) ||
132           (Lang <= dwarf::DW_LANG_hi_user && Lang >= dwarf::DW_LANG_lo_user)) &&
133          "Invalid Language tag");
134 
135   assert(!CUNode && "Can only make one compile unit per DIBuilder instance");
136   CUNode = DICompileUnit::getDistinct(
137       VMContext, Lang, File, Producer, isOptimized, Flags, RunTimeVer,
138       SplitName, Kind, nullptr, nullptr, nullptr, nullptr, nullptr, DWOId,
139       SplitDebugInlining, DebugInfoForProfiling);
140 
141   // Create a named metadata so that it is easier to find cu in a module.
142   NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
143   NMD->addOperand(CUNode);
144   trackIfUnresolved(CUNode);
145   return CUNode;
146 }
147 
148 static DIImportedEntity *
149 createImportedModule(LLVMContext &C, dwarf::Tag Tag, DIScope *Context,
150                      Metadata *NS, unsigned Line, StringRef Name,
151                      SmallVectorImpl<TrackingMDNodeRef> &AllImportedModules) {
152   unsigned EntitiesCount = C.pImpl->DIImportedEntitys.size();
153   auto *M = DIImportedEntity::get(C, Tag, Context, DINodeRef(NS), Line, Name);
154   if (EntitiesCount < C.pImpl->DIImportedEntitys.size())
155     // A new Imported Entity was just added to the context.
156     // Add it to the Imported Modules list.
157     AllImportedModules.emplace_back(M);
158   return M;
159 }
160 
161 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
162                                                   DINamespace *NS,
163                                                   unsigned Line) {
164   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
165                                 Context, NS, Line, StringRef(), AllImportedModules);
166 }
167 
168 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
169                                                   DIImportedEntity *NS,
170                                                   unsigned Line) {
171   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
172                                 Context, NS, Line, StringRef(), AllImportedModules);
173 }
174 
175 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context, DIModule *M,
176                                                   unsigned Line) {
177   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
178                                 Context, M, Line, StringRef(), AllImportedModules);
179 }
180 
181 DIImportedEntity *DIBuilder::createImportedDeclaration(DIScope *Context,
182                                                        DINode *Decl,
183                                                        unsigned Line,
184                                                        StringRef Name) {
185   // Make sure to use the unique identifier based metadata reference for
186   // types that have one.
187   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_declaration,
188                                 Context, Decl, Line, Name, AllImportedModules);
189 }
190 
191 DIFile *DIBuilder::createFile(StringRef Filename, StringRef Directory,
192                               DIFile::ChecksumKind CSKind, StringRef Checksum) {
193   return DIFile::get(VMContext, Filename, Directory, CSKind, Checksum);
194 }
195 
196 DIMacro *DIBuilder::createMacro(DIMacroFile *Parent, unsigned LineNumber,
197                                 unsigned MacroType, StringRef Name,
198                                 StringRef Value) {
199   assert(!Name.empty() && "Unable to create macro without name");
200   assert((MacroType == dwarf::DW_MACINFO_undef ||
201           MacroType == dwarf::DW_MACINFO_define) &&
202          "Unexpected macro type");
203   auto *M = DIMacro::get(VMContext, MacroType, LineNumber, Name, Value);
204   AllMacrosPerParent[Parent].insert(M);
205   return M;
206 }
207 
208 DIMacroFile *DIBuilder::createTempMacroFile(DIMacroFile *Parent,
209                                             unsigned LineNumber, DIFile *File) {
210   auto *MF = DIMacroFile::getTemporary(VMContext, dwarf::DW_MACINFO_start_file,
211                                        LineNumber, File, DIMacroNodeArray())
212                  .release();
213   AllMacrosPerParent[Parent].insert(MF);
214   // Add the new temporary DIMacroFile to the macro per parent map as a parent.
215   // This is needed to assure DIMacroFile with no children to have an entry in
216   // the map. Otherwise, it will not be resolved in DIBuilder::finalize().
217   AllMacrosPerParent.insert({MF, {}});
218   return MF;
219 }
220 
221 DIEnumerator *DIBuilder::createEnumerator(StringRef Name, int64_t Val) {
222   assert(!Name.empty() && "Unable to create enumerator without name");
223   return DIEnumerator::get(VMContext, Val, Name);
224 }
225 
226 DIBasicType *DIBuilder::createUnspecifiedType(StringRef Name) {
227   assert(!Name.empty() && "Unable to create type without name");
228   return DIBasicType::get(VMContext, dwarf::DW_TAG_unspecified_type, Name);
229 }
230 
231 DIBasicType *DIBuilder::createNullPtrType() {
232   return createUnspecifiedType("decltype(nullptr)");
233 }
234 
235 DIBasicType *DIBuilder::createBasicType(StringRef Name, uint64_t SizeInBits,
236                                         unsigned Encoding) {
237   assert(!Name.empty() && "Unable to create type without name");
238   return DIBasicType::get(VMContext, dwarf::DW_TAG_base_type, Name, SizeInBits,
239                           0, Encoding);
240 }
241 
242 DIDerivedType *DIBuilder::createQualifiedType(unsigned Tag, DIType *FromTy) {
243   return DIDerivedType::get(VMContext, Tag, "", nullptr, 0, nullptr, FromTy, 0,
244                             0, 0, DINode::FlagZero);
245 }
246 
247 DIDerivedType *DIBuilder::createPointerType(DIType *PointeeTy,
248                                             uint64_t SizeInBits,
249                                             uint32_t AlignInBits,
250                                             StringRef Name) {
251   // FIXME: Why is there a name here?
252   return DIDerivedType::get(VMContext, dwarf::DW_TAG_pointer_type, Name,
253                             nullptr, 0, nullptr, PointeeTy, SizeInBits,
254                             AlignInBits, 0, DINode::FlagZero);
255 }
256 
257 DIDerivedType *DIBuilder::createMemberPointerType(DIType *PointeeTy,
258                                                   DIType *Base,
259                                                   uint64_t SizeInBits,
260                                                   uint32_t AlignInBits,
261                                                   DINode::DIFlags Flags) {
262   return DIDerivedType::get(VMContext, dwarf::DW_TAG_ptr_to_member_type, "",
263                             nullptr, 0, nullptr, PointeeTy, SizeInBits,
264                             AlignInBits, 0, Flags, Base);
265 }
266 
267 DIDerivedType *DIBuilder::createReferenceType(unsigned Tag, DIType *RTy,
268                                               uint64_t SizeInBits,
269                                               uint32_t AlignInBits) {
270   assert(RTy && "Unable to create reference type");
271   return DIDerivedType::get(VMContext, Tag, "", nullptr, 0, nullptr, RTy,
272                             SizeInBits, AlignInBits, 0, DINode::FlagZero);
273 }
274 
275 DIDerivedType *DIBuilder::createTypedef(DIType *Ty, StringRef Name,
276                                         DIFile *File, unsigned LineNo,
277                                         DIScope *Context) {
278   return DIDerivedType::get(VMContext, dwarf::DW_TAG_typedef, Name, File,
279                             LineNo, getNonCompileUnitScope(Context), Ty, 0, 0,
280                             0, DINode::FlagZero);
281 }
282 
283 DIDerivedType *DIBuilder::createFriend(DIType *Ty, DIType *FriendTy) {
284   assert(Ty && "Invalid type!");
285   assert(FriendTy && "Invalid friend type!");
286   return DIDerivedType::get(VMContext, dwarf::DW_TAG_friend, "", nullptr, 0, Ty,
287                             FriendTy, 0, 0, 0, DINode::FlagZero);
288 }
289 
290 DIDerivedType *DIBuilder::createInheritance(DIType *Ty, DIType *BaseTy,
291                                             uint64_t BaseOffset,
292                                             DINode::DIFlags Flags) {
293   assert(Ty && "Unable to create inheritance");
294   return DIDerivedType::get(VMContext, dwarf::DW_TAG_inheritance, "", nullptr,
295                             0, Ty, BaseTy, 0, 0, BaseOffset, Flags);
296 }
297 
298 DIDerivedType *DIBuilder::createMemberType(DIScope *Scope, StringRef Name,
299                                            DIFile *File, unsigned LineNumber,
300                                            uint64_t SizeInBits,
301                                            uint32_t AlignInBits,
302                                            uint64_t OffsetInBits,
303                                            DINode::DIFlags Flags, DIType *Ty) {
304   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
305                             LineNumber, getNonCompileUnitScope(Scope), Ty,
306                             SizeInBits, AlignInBits, OffsetInBits, Flags);
307 }
308 
309 static ConstantAsMetadata *getConstantOrNull(Constant *C) {
310   if (C)
311     return ConstantAsMetadata::get(C);
312   return nullptr;
313 }
314 
315 DIDerivedType *DIBuilder::createBitFieldMemberType(
316     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
317     uint64_t SizeInBits, uint64_t OffsetInBits, uint64_t StorageOffsetInBits,
318     DINode::DIFlags Flags, DIType *Ty) {
319   Flags |= DINode::FlagBitField;
320   return DIDerivedType::get(
321       VMContext, dwarf::DW_TAG_member, Name, File, LineNumber,
322       getNonCompileUnitScope(Scope), Ty, SizeInBits, /* AlignInBits */ 0,
323       OffsetInBits, Flags,
324       ConstantAsMetadata::get(ConstantInt::get(IntegerType::get(VMContext, 64),
325                                                StorageOffsetInBits)));
326 }
327 
328 DIDerivedType *
329 DIBuilder::createStaticMemberType(DIScope *Scope, StringRef Name, DIFile *File,
330                                   unsigned LineNumber, DIType *Ty,
331                                   DINode::DIFlags Flags, llvm::Constant *Val,
332                                   uint32_t AlignInBits) {
333   Flags |= DINode::FlagStaticMember;
334   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
335                             LineNumber, getNonCompileUnitScope(Scope), Ty, 0,
336                             AlignInBits, 0, Flags, getConstantOrNull(Val));
337 }
338 
339 DIDerivedType *
340 DIBuilder::createObjCIVar(StringRef Name, DIFile *File, unsigned LineNumber,
341                           uint64_t SizeInBits, uint32_t AlignInBits,
342                           uint64_t OffsetInBits, DINode::DIFlags Flags,
343                           DIType *Ty, MDNode *PropertyNode) {
344   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
345                             LineNumber, getNonCompileUnitScope(File), Ty,
346                             SizeInBits, AlignInBits, OffsetInBits, Flags,
347                             PropertyNode);
348 }
349 
350 DIObjCProperty *
351 DIBuilder::createObjCProperty(StringRef Name, DIFile *File, unsigned LineNumber,
352                               StringRef GetterName, StringRef SetterName,
353                               unsigned PropertyAttributes, DIType *Ty) {
354   return DIObjCProperty::get(VMContext, Name, File, LineNumber, GetterName,
355                              SetterName, PropertyAttributes, Ty);
356 }
357 
358 DITemplateTypeParameter *
359 DIBuilder::createTemplateTypeParameter(DIScope *Context, StringRef Name,
360                                        DIType *Ty) {
361   assert((!Context || isa<DICompileUnit>(Context)) && "Expected compile unit");
362   return DITemplateTypeParameter::get(VMContext, Name, Ty);
363 }
364 
365 static DITemplateValueParameter *
366 createTemplateValueParameterHelper(LLVMContext &VMContext, unsigned Tag,
367                                    DIScope *Context, StringRef Name, DIType *Ty,
368                                    Metadata *MD) {
369   assert((!Context || isa<DICompileUnit>(Context)) && "Expected compile unit");
370   return DITemplateValueParameter::get(VMContext, Tag, Name, Ty, MD);
371 }
372 
373 DITemplateValueParameter *
374 DIBuilder::createTemplateValueParameter(DIScope *Context, StringRef Name,
375                                         DIType *Ty, Constant *Val) {
376   return createTemplateValueParameterHelper(
377       VMContext, dwarf::DW_TAG_template_value_parameter, Context, Name, Ty,
378       getConstantOrNull(Val));
379 }
380 
381 DITemplateValueParameter *
382 DIBuilder::createTemplateTemplateParameter(DIScope *Context, StringRef Name,
383                                            DIType *Ty, StringRef Val) {
384   return createTemplateValueParameterHelper(
385       VMContext, dwarf::DW_TAG_GNU_template_template_param, Context, Name, Ty,
386       MDString::get(VMContext, Val));
387 }
388 
389 DITemplateValueParameter *
390 DIBuilder::createTemplateParameterPack(DIScope *Context, StringRef Name,
391                                        DIType *Ty, DINodeArray Val) {
392   return createTemplateValueParameterHelper(
393       VMContext, dwarf::DW_TAG_GNU_template_parameter_pack, Context, Name, Ty,
394       Val.get());
395 }
396 
397 DICompositeType *DIBuilder::createClassType(
398     DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
399     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
400     DINode::DIFlags Flags, DIType *DerivedFrom, DINodeArray Elements,
401     DIType *VTableHolder, MDNode *TemplateParams, StringRef UniqueIdentifier) {
402   assert((!Context || isa<DIScope>(Context)) &&
403          "createClassType should be called with a valid Context");
404 
405   auto *R = DICompositeType::get(
406       VMContext, dwarf::DW_TAG_structure_type, Name, File, LineNumber,
407       getNonCompileUnitScope(Context), DerivedFrom, SizeInBits, AlignInBits,
408       OffsetInBits, Flags, Elements, 0, VTableHolder,
409       cast_or_null<MDTuple>(TemplateParams), UniqueIdentifier);
410   trackIfUnresolved(R);
411   return R;
412 }
413 
414 DICompositeType *DIBuilder::createStructType(
415     DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
416     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
417     DIType *DerivedFrom, DINodeArray Elements, unsigned RunTimeLang,
418     DIType *VTableHolder, StringRef UniqueIdentifier) {
419   auto *R = DICompositeType::get(
420       VMContext, dwarf::DW_TAG_structure_type, Name, File, LineNumber,
421       getNonCompileUnitScope(Context), DerivedFrom, SizeInBits, AlignInBits, 0,
422       Flags, Elements, RunTimeLang, VTableHolder, nullptr, UniqueIdentifier);
423   trackIfUnresolved(R);
424   return R;
425 }
426 
427 DICompositeType *DIBuilder::createUnionType(
428     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
429     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
430     DINodeArray Elements, unsigned RunTimeLang, StringRef UniqueIdentifier) {
431   auto *R = DICompositeType::get(
432       VMContext, dwarf::DW_TAG_union_type, Name, File, LineNumber,
433       getNonCompileUnitScope(Scope), nullptr, SizeInBits, AlignInBits, 0, Flags,
434       Elements, RunTimeLang, nullptr, nullptr, UniqueIdentifier);
435   trackIfUnresolved(R);
436   return R;
437 }
438 
439 DISubroutineType *DIBuilder::createSubroutineType(DITypeRefArray ParameterTypes,
440                                                   DINode::DIFlags Flags,
441                                                   unsigned CC) {
442   return DISubroutineType::get(VMContext, Flags, CC, ParameterTypes);
443 }
444 
445 DICompositeType *DIBuilder::createExternalTypeRef(unsigned Tag, DIFile *File,
446                                                   StringRef UniqueIdentifier) {
447   assert(!UniqueIdentifier.empty() && "external type ref without uid");
448   return DICompositeType::get(VMContext, Tag, "", nullptr, 0, nullptr, nullptr,
449                               0, 0, 0, DINode::FlagExternalTypeRef, nullptr, 0,
450                               nullptr, nullptr, UniqueIdentifier);
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   auto *Node = getSubprogram(
682       /* IsDistinct = */ isDefinition, VMContext,
683       getNonCompileUnitScope(Context), Name, LinkageName, File, LineNo, Ty,
684       isLocalToUnit, isDefinition, ScopeLine, nullptr, 0, 0, 0, Flags,
685       isOptimized, isDefinition ? CUNode : nullptr, TParams, Decl,
686       MDTuple::getTemporary(VMContext, None).release());
687 
688   if (isDefinition)
689     AllSubprograms.push_back(Node);
690   trackIfUnresolved(Node);
691   return Node;
692 }
693 
694 DISubprogram *DIBuilder::createTempFunctionFwdDecl(
695     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
696     unsigned LineNo, DISubroutineType *Ty, bool isLocalToUnit,
697     bool isDefinition, unsigned ScopeLine, DINode::DIFlags Flags,
698     bool isOptimized, DITemplateParameterArray TParams, DISubprogram *Decl) {
699   return DISubprogram::getTemporary(
700              VMContext, getNonCompileUnitScope(Context), Name, LinkageName,
701              File, LineNo, Ty, isLocalToUnit, isDefinition, ScopeLine, nullptr,
702              0, 0, 0, Flags, isOptimized, isDefinition ? CUNode : nullptr,
703              TParams, Decl, nullptr)
704       .release();
705 }
706 
707 DISubprogram *DIBuilder::createMethod(DIScope *Context, StringRef Name,
708                                       StringRef LinkageName, DIFile *F,
709                                       unsigned LineNo, DISubroutineType *Ty,
710                                       bool isLocalToUnit, bool isDefinition,
711                                       unsigned VK, unsigned VIndex,
712                                       int ThisAdjustment, DIType *VTableHolder,
713                                       DINode::DIFlags Flags, bool isOptimized,
714                                       DITemplateParameterArray TParams) {
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);
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                                         DIFile *File, unsigned LineNo,
733                                         bool ExportSymbols) {
734   return DINamespace::get(VMContext, getNonCompileUnitScope(Scope), File, Name,
735                           LineNo, ExportSymbols);
736 }
737 
738 DIModule *DIBuilder::createModule(DIScope *Scope, StringRef Name,
739                                   StringRef ConfigurationMacros,
740                                   StringRef IncludePath,
741                                   StringRef ISysRoot) {
742  return DIModule::get(VMContext, getNonCompileUnitScope(Scope), Name,
743                       ConfigurationMacros, IncludePath, ISysRoot);
744 }
745 
746 DILexicalBlockFile *DIBuilder::createLexicalBlockFile(DIScope *Scope,
747                                                       DIFile *File,
748                                                       unsigned Discriminator) {
749   return DILexicalBlockFile::get(VMContext, Scope, File, Discriminator);
750 }
751 
752 DILexicalBlock *DIBuilder::createLexicalBlock(DIScope *Scope, DIFile *File,
753                                               unsigned Line, unsigned Col) {
754   // Make these distinct, to avoid merging two lexical blocks on the same
755   // file/line/column.
756   return DILexicalBlock::getDistinct(VMContext, getNonCompileUnitScope(Scope),
757                                      File, Line, Col);
758 }
759 
760 static Value *getDbgIntrinsicValueImpl(LLVMContext &VMContext, Value *V) {
761   assert(V && "no value passed to dbg intrinsic");
762   return MetadataAsValue::get(VMContext, ValueAsMetadata::get(V));
763 }
764 
765 static Instruction *withDebugLoc(Instruction *I, const DILocation *DL) {
766   I->setDebugLoc(const_cast<DILocation *>(DL));
767   return I;
768 }
769 
770 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
771                                       DIExpression *Expr, const DILocation *DL,
772                                       Instruction *InsertBefore) {
773   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.declare");
774   assert(DL && "Expected debug loc");
775   assert(DL->getScope()->getSubprogram() ==
776              VarInfo->getScope()->getSubprogram() &&
777          "Expected matching subprograms");
778   if (!DeclareFn)
779     DeclareFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_declare);
780 
781   trackIfUnresolved(VarInfo);
782   trackIfUnresolved(Expr);
783   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, Storage),
784                    MetadataAsValue::get(VMContext, VarInfo),
785                    MetadataAsValue::get(VMContext, Expr)};
786   return withDebugLoc(CallInst::Create(DeclareFn, Args, "", InsertBefore), DL);
787 }
788 
789 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
790                                       DIExpression *Expr, const DILocation *DL,
791                                       BasicBlock *InsertAtEnd) {
792   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.declare");
793   assert(DL && "Expected debug loc");
794   assert(DL->getScope()->getSubprogram() ==
795              VarInfo->getScope()->getSubprogram() &&
796          "Expected matching subprograms");
797   if (!DeclareFn)
798     DeclareFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_declare);
799 
800   trackIfUnresolved(VarInfo);
801   trackIfUnresolved(Expr);
802   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, Storage),
803                    MetadataAsValue::get(VMContext, VarInfo),
804                    MetadataAsValue::get(VMContext, Expr)};
805 
806   // If this block already has a terminator then insert this intrinsic
807   // before the terminator.
808   if (TerminatorInst *T = InsertAtEnd->getTerminator())
809     return withDebugLoc(CallInst::Create(DeclareFn, Args, "", T), DL);
810   return withDebugLoc(CallInst::Create(DeclareFn, Args, "", InsertAtEnd), DL);
811 }
812 
813 Instruction *DIBuilder::insertDbgValueIntrinsic(Value *V, uint64_t Offset,
814                                                 DILocalVariable *VarInfo,
815                                                 DIExpression *Expr,
816                                                 const DILocation *DL,
817                                                 Instruction *InsertBefore) {
818   assert(V && "no value passed to dbg.value");
819   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.value");
820   assert(DL && "Expected debug loc");
821   assert(DL->getScope()->getSubprogram() ==
822              VarInfo->getScope()->getSubprogram() &&
823          "Expected matching subprograms");
824   if (!ValueFn)
825     ValueFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_value);
826 
827   trackIfUnresolved(VarInfo);
828   trackIfUnresolved(Expr);
829   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, V),
830                    ConstantInt::get(Type::getInt64Ty(VMContext), Offset),
831                    MetadataAsValue::get(VMContext, VarInfo),
832                    MetadataAsValue::get(VMContext, Expr)};
833   return withDebugLoc(CallInst::Create(ValueFn, Args, "", InsertBefore), DL);
834 }
835 
836 Instruction *DIBuilder::insertDbgValueIntrinsic(Value *V, uint64_t Offset,
837                                                 DILocalVariable *VarInfo,
838                                                 DIExpression *Expr,
839                                                 const DILocation *DL,
840                                                 BasicBlock *InsertAtEnd) {
841   assert(V && "no value passed to dbg.value");
842   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.value");
843   assert(DL && "Expected debug loc");
844   assert(DL->getScope()->getSubprogram() ==
845              VarInfo->getScope()->getSubprogram() &&
846          "Expected matching subprograms");
847   if (!ValueFn)
848     ValueFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_value);
849 
850   trackIfUnresolved(VarInfo);
851   trackIfUnresolved(Expr);
852   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, V),
853                    ConstantInt::get(Type::getInt64Ty(VMContext), Offset),
854                    MetadataAsValue::get(VMContext, VarInfo),
855                    MetadataAsValue::get(VMContext, Expr)};
856 
857   return withDebugLoc(CallInst::Create(ValueFn, Args, "", InsertAtEnd), DL);
858 }
859 
860 void DIBuilder::replaceVTableHolder(DICompositeType *&T,
861                                     DICompositeType *VTableHolder) {
862   {
863     TypedTrackingMDRef<DICompositeType> N(T);
864     N->replaceVTableHolder(VTableHolder);
865     T = N.get();
866   }
867 
868   // If this didn't create a self-reference, just return.
869   if (T != VTableHolder)
870     return;
871 
872   // Look for unresolved operands.  T will drop RAUW support, orphaning any
873   // cycles underneath it.
874   if (T->isResolved())
875     for (const MDOperand &O : T->operands())
876       if (auto *N = dyn_cast_or_null<MDNode>(O))
877         trackIfUnresolved(N);
878 }
879 
880 void DIBuilder::replaceArrays(DICompositeType *&T, DINodeArray Elements,
881                               DINodeArray TParams) {
882   {
883     TypedTrackingMDRef<DICompositeType> N(T);
884     if (Elements)
885       N->replaceElements(Elements);
886     if (TParams)
887       N->replaceTemplateParams(DITemplateParameterArray(TParams));
888     T = N.get();
889   }
890 
891   // If T isn't resolved, there's no problem.
892   if (!T->isResolved())
893     return;
894 
895   // If T is resolved, it may be due to a self-reference cycle.  Track the
896   // arrays explicitly if they're unresolved, or else the cycles will be
897   // orphaned.
898   if (Elements)
899     trackIfUnresolved(Elements.get());
900   if (TParams)
901     trackIfUnresolved(TParams.get());
902 }
903