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