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