lib/IR/DIBuilder.cpp

   1 //===--- DIBuilder.cpp - Debug Information Builder ------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the DIBuilder.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/IR/DIBuilder.h"
  14 #include "llvm/IR/IRBuilder.h"
  15 #include "LLVMContextImpl.h"
  16 #include "llvm/ADT/Optional.h"
  17 #include "llvm/ADT/STLExtras.h"
  18 #include "llvm/BinaryFormat/Dwarf.h"
  19 #include "llvm/IR/Constants.h"
  20 #include "llvm/IR/DebugInfo.h"
  21 #include "llvm/IR/IntrinsicInst.h"
  22 #include "llvm/IR/Module.h"
  23 #include "llvm/Support/Debug.h"
  24
  25 using namespace llvm;
  26 using namespace llvm::dwarf;
  27
  28 static cl::opt<bool>
  29     UseDbgAddr("use-dbg-addr",
  30                llvm::cl::desc("Use llvm.dbg.addr for all local variables"),
  31                cl::init(false), cl::Hidden);
  32
  33 DIBuilder::DIBuilder(Module &m, bool AllowUnresolvedNodes, DICompileUnit *CU)
  34   : M(m), VMContext(M.getContext()), CUNode(CU),
  35       DeclareFn(nullptr), ValueFn(nullptr), LabelFn(nullptr),
  36       AllowUnresolvedNodes(AllowUnresolvedNodes) {}
  37
  38 void DIBuilder::trackIfUnresolved(MDNode *N) {
  39   if (!N)
  40     return;
  41   if (N->isResolved())
  42     return;
  43
  44   assert(AllowUnresolvedNodes && "Cannot handle unresolved nodes");
  45   UnresolvedNodes.emplace_back(N);
  46 }
  47
  48 void DIBuilder::finalizeSubprogram(DISubprogram *SP) {
  49   MDTuple *Temp = SP->getRetainedNodes().get();
  50   if (!Temp || !Temp->isTemporary())
  51     return;
  52
  53   SmallVector<Metadata *, 16> RetainedNodes;
  54
  55   auto PV = PreservedVariables.find(SP);
  56   if (PV != PreservedVariables.end())
  57     RetainedNodes.append(PV->second.begin(), PV->second.end());
  58
  59   auto PL = PreservedLabels.find(SP);
  60   if (PL != PreservedLabels.end())
  61     RetainedNodes.append(PL->second.begin(), PL->second.end());
  62
  63   DINodeArray Node = getOrCreateArray(RetainedNodes);
  64
  65   TempMDTuple(Temp)->replaceAllUsesWith(Node.get());
  66 }
  67
  68 void DIBuilder::finalize() {
  69   if (!CUNode) {
  70     assert(!AllowUnresolvedNodes &&
  71            "creating type nodes without a CU is not supported");
  72     return;
  73   }
  74
  75   CUNode->replaceEnumTypes(MDTuple::get(VMContext, AllEnumTypes));
  76
  77   SmallVector<Metadata *, 16> RetainValues;
  78   // Declarations and definitions of the same type may be retained. Some
  79   // clients RAUW these pairs, leaving duplicates in the retained types
  80   // list. Use a set to remove the duplicates while we transform the
  81   // TrackingVHs back into Values.
  82   SmallPtrSet<Metadata *, 16> RetainSet;
  83   for (unsigned I = 0, E = AllRetainTypes.size(); I < E; I++)
  84     if (RetainSet.insert(AllRetainTypes[I]).second)
  85       RetainValues.push_back(AllRetainTypes[I]);
  86
  87   if (!RetainValues.empty())
  88     CUNode->replaceRetainedTypes(MDTuple::get(VMContext, RetainValues));
  89
  90   DISubprogramArray SPs = MDTuple::get(VMContext, AllSubprograms);
  91   for (auto *SP : SPs)
  92     finalizeSubprogram(SP);
  93   for (auto *N : RetainValues)
  94     if (auto *SP = dyn_cast<DISubprogram>(N))
  95       finalizeSubprogram(SP);
  96
  97   if (!AllGVs.empty())
  98     CUNode->replaceGlobalVariables(MDTuple::get(VMContext, AllGVs));
  99
 100   if (!AllImportedModules.empty())
 101     CUNode->replaceImportedEntities(MDTuple::get(
 102         VMContext, SmallVector<Metadata *, 16>(AllImportedModules.begin(),
 103                                                AllImportedModules.end())));
 104
 105   for (const auto &I : AllMacrosPerParent) {
 106     // DIMacroNode's with nullptr parent are DICompileUnit direct children.
 107     if (!I.first) {
 108       CUNode->replaceMacros(MDTuple::get(VMContext, I.second.getArrayRef()));
 109       continue;
 110     }
 111     // Otherwise, it must be a temporary DIMacroFile that need to be resolved.
 112     auto *TMF = cast<DIMacroFile>(I.first);
 113     auto *MF = DIMacroFile::get(VMContext, dwarf::DW_MACINFO_start_file,
 114                                 TMF->getLine(), TMF->getFile(),
 115                                 getOrCreateMacroArray(I.second.getArrayRef()));
 116     replaceTemporary(llvm::TempDIMacroNode(TMF), MF);
 117   }
 118
 119   // Now that all temp nodes have been replaced or deleted, resolve remaining
 120   // cycles.
 121   for (const auto &N : UnresolvedNodes)
 122     if (N && !N->isResolved())
 123       N->resolveCycles();
 124   UnresolvedNodes.clear();
 125
 126   // Can't handle unresolved nodes anymore.
 127   AllowUnresolvedNodes = false;
 128 }
 129
 130 /// If N is compile unit return NULL otherwise return N.
 131 static DIScope *getNonCompileUnitScope(DIScope *N) {
 132   if (!N || isa<DICompileUnit>(N))
 133     return nullptr;
 134   return cast<DIScope>(N);
 135 }
 136
 137 DICompileUnit *DIBuilder::createCompileUnit(
 138     unsigned Lang, DIFile *File, StringRef Producer, bool isOptimized,
 139     StringRef Flags, unsigned RunTimeVer, StringRef SplitName,
 140     DICompileUnit::DebugEmissionKind Kind, uint64_t DWOId,
 141     bool SplitDebugInlining, bool DebugInfoForProfiling,
 142     DICompileUnit::DebugNameTableKind NameTableKind, bool RangesBaseAddress) {
 143
 144   assert(((Lang <= dwarf::DW_LANG_Fortran08 && Lang >= dwarf::DW_LANG_C89) ||
 145           (Lang <= dwarf::DW_LANG_hi_user && Lang >= dwarf::DW_LANG_lo_user)) &&
 146          "Invalid Language tag");
 147
 148   assert(!CUNode && "Can only make one compile unit per DIBuilder instance");
 149   CUNode = DICompileUnit::getDistinct(
 150       VMContext, Lang, File, Producer, isOptimized, Flags, RunTimeVer,
 151       SplitName, Kind, nullptr, nullptr, nullptr, nullptr, nullptr, DWOId,
 152       SplitDebugInlining, DebugInfoForProfiling, NameTableKind,
 153       RangesBaseAddress);
 154
 155   // Create a named metadata so that it is easier to find cu in a module.
 156   NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
 157   NMD->addOperand(CUNode);
 158   trackIfUnresolved(CUNode);
 159   return CUNode;
 160 }
 161
 162 static DIImportedEntity *
 163 createImportedModule(LLVMContext &C, dwarf::Tag Tag, DIScope *Context,
 164                      Metadata *NS, DIFile *File, unsigned Line, StringRef Name,
 165                      SmallVectorImpl<TrackingMDNodeRef> &AllImportedModules) {
 166   if (Line)
 167     assert(File && "Source location has line number but no file");
 168   unsigned EntitiesCount = C.pImpl->DIImportedEntitys.size();
 169   auto *M = DIImportedEntity::get(C, Tag, Context, cast_or_null<DINode>(NS),
 170                                   File, Line, Name);
 171   if (EntitiesCount < C.pImpl->DIImportedEntitys.size())
 172     // A new Imported Entity was just added to the context.
 173     // Add it to the Imported Modules list.
 174     AllImportedModules.emplace_back(M);
 175   return M;
 176 }
 177
 178 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
 179                                                   DINamespace *NS, DIFile *File,
 180                                                   unsigned Line) {
 181   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
 182                                 Context, NS, File, Line, StringRef(),
 183                                 AllImportedModules);
 184 }
 185
 186 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
 187                                                   DIImportedEntity *NS,
 188                                                   DIFile *File, unsigned Line) {
 189   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
 190                                 Context, NS, File, Line, StringRef(),
 191                                 AllImportedModules);
 192 }
 193
 194 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context, DIModule *M,
 195                                                   DIFile *File, unsigned Line) {
 196   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
 197                                 Context, M, File, Line, StringRef(),
 198                                 AllImportedModules);
 199 }
 200
 201 DIImportedEntity *DIBuilder::createImportedDeclaration(DIScope *Context,
 202                                                        DINode *Decl,
 203                                                        DIFile *File,
 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, File, Line, Name,
 210                                 AllImportedModules);
 211 }
 212
 213 DIFile *DIBuilder::createFile(StringRef Filename, StringRef Directory,
 214                               Optional<DIFile::ChecksumInfo<StringRef>> CS,
 215                               Optional<StringRef> Source) {
 216   return DIFile::get(VMContext, Filename, Directory, CS, Source);
 217 }
 218
 219 DIMacro *DIBuilder::createMacro(DIMacroFile *Parent, unsigned LineNumber,
 220                                 unsigned MacroType, StringRef Name,
 221                                 StringRef Value) {
 222   assert(!Name.empty() && "Unable to create macro without name");
 223   assert((MacroType == dwarf::DW_MACINFO_undef ||
 224           MacroType == dwarf::DW_MACINFO_define) &&
 225          "Unexpected macro type");
 226   auto *M = DIMacro::get(VMContext, MacroType, LineNumber, Name, Value);
 227   AllMacrosPerParent[Parent].insert(M);
 228   return M;
 229 }
 230
 231 DIMacroFile *DIBuilder::createTempMacroFile(DIMacroFile *Parent,
 232                                             unsigned LineNumber, DIFile *File) {
 233   auto *MF = DIMacroFile::getTemporary(VMContext, dwarf::DW_MACINFO_start_file,
 234                                        LineNumber, File, DIMacroNodeArray())
 235                  .release();
 236   AllMacrosPerParent[Parent].insert(MF);
 237   // Add the new temporary DIMacroFile to the macro per parent map as a parent.
 238   // This is needed to assure DIMacroFile with no children to have an entry in
 239   // the map. Otherwise, it will not be resolved in DIBuilder::finalize().
 240   AllMacrosPerParent.insert({MF, {}});
 241   return MF;
 242 }
 243
 244 DIEnumerator *DIBuilder::createEnumerator(StringRef Name, int64_t Val,
 245                                           bool IsUnsigned) {
 246   assert(!Name.empty() && "Unable to create enumerator without name");
 247   return DIEnumerator::get(VMContext, Val, IsUnsigned, Name);
 248 }
 249
 250 DIBasicType *DIBuilder::createUnspecifiedType(StringRef Name) {
 251   assert(!Name.empty() && "Unable to create type without name");
 252   return DIBasicType::get(VMContext, dwarf::DW_TAG_unspecified_type, Name);
 253 }
 254
 255 DIBasicType *DIBuilder::createNullPtrType() {
 256   return createUnspecifiedType("decltype(nullptr)");
 257 }
 258
 259 DIBasicType *DIBuilder::createBasicType(StringRef Name, uint64_t SizeInBits,
 260                                         unsigned Encoding,
 261                                         DINode::DIFlags Flags) {
 262   assert(!Name.empty() && "Unable to create type without name");
 263   return DIBasicType::get(VMContext, dwarf::DW_TAG_base_type, Name, SizeInBits,
 264                           0, Encoding, Flags);
 265 }
 266
 267 DIDerivedType *DIBuilder::createQualifiedType(unsigned Tag, DIType *FromTy) {
 268   return DIDerivedType::get(VMContext, Tag, "", nullptr, 0, nullptr, FromTy, 0,
 269                             0, 0, None, DINode::FlagZero);
 270 }
 271
 272 DIDerivedType *DIBuilder::createPointerType(
 273     DIType *PointeeTy,
 274     uint64_t SizeInBits,
 275     uint32_t AlignInBits,
 276     Optional<unsigned> DWARFAddressSpace,
 277     StringRef Name) {
 278   // FIXME: Why is there a name here?
 279   return DIDerivedType::get(VMContext, dwarf::DW_TAG_pointer_type, Name,
 280                             nullptr, 0, nullptr, PointeeTy, SizeInBits,
 281                             AlignInBits, 0, DWARFAddressSpace,
 282                             DINode::FlagZero);
 283 }
 284
 285 DIDerivedType *DIBuilder::createMemberPointerType(DIType *PointeeTy,
 286                                                   DIType *Base,
 287                                                   uint64_t SizeInBits,
 288                                                   uint32_t AlignInBits,
 289                                                   DINode::DIFlags Flags) {
 290   return DIDerivedType::get(VMContext, dwarf::DW_TAG_ptr_to_member_type, "",
 291                             nullptr, 0, nullptr, PointeeTy, SizeInBits,
 292                             AlignInBits, 0, None, Flags, Base);
 293 }
 294
 295 DIDerivedType *DIBuilder::createReferenceType(
 296     unsigned Tag, DIType *RTy,
 297     uint64_t SizeInBits,
 298     uint32_t AlignInBits,
 299     Optional<unsigned> DWARFAddressSpace) {
 300   assert(RTy && "Unable to create reference type");
 301   return DIDerivedType::get(VMContext, Tag, "", nullptr, 0, nullptr, RTy,
 302                             SizeInBits, AlignInBits, 0, DWARFAddressSpace,
 303                             DINode::FlagZero);
 304 }
 305
 306 DIDerivedType *DIBuilder::createTypedef(DIType *Ty, StringRef Name,
 307                                         DIFile *File, unsigned LineNo,
 308                                         DIScope *Context) {
 309   return DIDerivedType::get(VMContext, dwarf::DW_TAG_typedef, Name, File,
 310                             LineNo, getNonCompileUnitScope(Context), Ty, 0, 0,
 311                             0, None, DINode::FlagZero);
 312 }
 313
 314 DIDerivedType *DIBuilder::createFriend(DIType *Ty, DIType *FriendTy) {
 315   assert(Ty && "Invalid type!");
 316   assert(FriendTy && "Invalid friend type!");
 317   return DIDerivedType::get(VMContext, dwarf::DW_TAG_friend, "", nullptr, 0, Ty,
 318                             FriendTy, 0, 0, 0, None, DINode::FlagZero);
 319 }
 320
 321 DIDerivedType *DIBuilder::createInheritance(DIType *Ty, DIType *BaseTy,
 322                                             uint64_t BaseOffset,
 323                                             uint32_t VBPtrOffset,
 324                                             DINode::DIFlags Flags) {
 325   assert(Ty && "Unable to create inheritance");
 326   Metadata *ExtraData = ConstantAsMetadata::get(
 327       ConstantInt::get(IntegerType::get(VMContext, 32), VBPtrOffset));
 328   return DIDerivedType::get(VMContext, dwarf::DW_TAG_inheritance, "", nullptr,
 329                             0, Ty, BaseTy, 0, 0, BaseOffset, None,
 330                             Flags, ExtraData);
 331 }
 332
 333 DIDerivedType *DIBuilder::createMemberType(DIScope *Scope, StringRef Name,
 334                                            DIFile *File, unsigned LineNumber,
 335                                            uint64_t SizeInBits,
 336                                            uint32_t AlignInBits,
 337                                            uint64_t OffsetInBits,
 338                                            DINode::DIFlags Flags, DIType *Ty) {
 339   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
 340                             LineNumber, getNonCompileUnitScope(Scope), Ty,
 341                             SizeInBits, AlignInBits, OffsetInBits, None, Flags);
 342 }
 343
 344 static ConstantAsMetadata *getConstantOrNull(Constant *C) {
 345   if (C)
 346     return ConstantAsMetadata::get(C);
 347   return nullptr;
 348 }
 349
 350 DIDerivedType *DIBuilder::createVariantMemberType(
 351     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
 352     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
 353     Constant *Discriminant, DINode::DIFlags Flags, DIType *Ty) {
 354   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
 355                             LineNumber, getNonCompileUnitScope(Scope), Ty,
 356                             SizeInBits, AlignInBits, OffsetInBits, None, Flags,
 357                             getConstantOrNull(Discriminant));
 358 }
 359
 360 DIDerivedType *DIBuilder::createBitFieldMemberType(
 361     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
 362     uint64_t SizeInBits, uint64_t OffsetInBits, uint64_t StorageOffsetInBits,
 363     DINode::DIFlags Flags, DIType *Ty) {
 364   Flags |= DINode::FlagBitField;
 365   return DIDerivedType::get(
 366       VMContext, dwarf::DW_TAG_member, Name, File, LineNumber,
 367       getNonCompileUnitScope(Scope), Ty, SizeInBits, /* AlignInBits */ 0,
 368       OffsetInBits, None, Flags,
 369       ConstantAsMetadata::get(ConstantInt::get(IntegerType::get(VMContext, 64),
 370                                                StorageOffsetInBits)));
 371 }
 372
 373 DIDerivedType *
 374 DIBuilder::createStaticMemberType(DIScope *Scope, StringRef Name, DIFile *File,
 375                                   unsigned LineNumber, DIType *Ty,
 376                                   DINode::DIFlags Flags, llvm::Constant *Val,
 377                                   uint32_t AlignInBits) {
 378   Flags |= DINode::FlagStaticMember;
 379   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
 380                             LineNumber, getNonCompileUnitScope(Scope), Ty, 0,
 381                             AlignInBits, 0, None, Flags,
 382                             getConstantOrNull(Val));
 383 }
 384
 385 DIDerivedType *
 386 DIBuilder::createObjCIVar(StringRef Name, DIFile *File, unsigned LineNumber,
 387                           uint64_t SizeInBits, uint32_t AlignInBits,
 388                           uint64_t OffsetInBits, DINode::DIFlags Flags,
 389                           DIType *Ty, MDNode *PropertyNode) {
 390   return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
 391                             LineNumber, getNonCompileUnitScope(File), Ty,
 392                             SizeInBits, AlignInBits, OffsetInBits, None, Flags,
 393                             PropertyNode);
 394 }
 395
 396 DIObjCProperty *
 397 DIBuilder::createObjCProperty(StringRef Name, DIFile *File, unsigned LineNumber,
 398                               StringRef GetterName, StringRef SetterName,
 399                               unsigned PropertyAttributes, DIType *Ty) {
 400   return DIObjCProperty::get(VMContext, Name, File, LineNumber, GetterName,
 401                              SetterName, PropertyAttributes, Ty);
 402 }
 403
 404 DITemplateTypeParameter *
 405 DIBuilder::createTemplateTypeParameter(DIScope *Context, StringRef Name,
 406                                        DIType *Ty) {
 407   assert((!Context || isa<DICompileUnit>(Context)) && "Expected compile unit");
 408   return DITemplateTypeParameter::get(VMContext, Name, Ty);
 409 }
 410
 411 static DITemplateValueParameter *
 412 createTemplateValueParameterHelper(LLVMContext &VMContext, unsigned Tag,
 413                                    DIScope *Context, StringRef Name, DIType *Ty,
 414                                    Metadata *MD) {
 415   assert((!Context || isa<DICompileUnit>(Context)) && "Expected compile unit");
 416   return DITemplateValueParameter::get(VMContext, Tag, Name, Ty, MD);
 417 }
 418
 419 DITemplateValueParameter *
 420 DIBuilder::createTemplateValueParameter(DIScope *Context, StringRef Name,
 421                                         DIType *Ty, Constant *Val) {
 422   return createTemplateValueParameterHelper(
 423       VMContext, dwarf::DW_TAG_template_value_parameter, Context, Name, Ty,
 424       getConstantOrNull(Val));
 425 }
 426
 427 DITemplateValueParameter *
 428 DIBuilder::createTemplateTemplateParameter(DIScope *Context, StringRef Name,
 429                                            DIType *Ty, StringRef Val) {
 430   return createTemplateValueParameterHelper(
 431       VMContext, dwarf::DW_TAG_GNU_template_template_param, Context, Name, Ty,
 432       MDString::get(VMContext, Val));
 433 }
 434
 435 DITemplateValueParameter *
 436 DIBuilder::createTemplateParameterPack(DIScope *Context, StringRef Name,
 437                                        DIType *Ty, DINodeArray Val) {
 438   return createTemplateValueParameterHelper(
 439       VMContext, dwarf::DW_TAG_GNU_template_parameter_pack, Context, Name, Ty,
 440       Val.get());
 441 }
 442
 443 DICompositeType *DIBuilder::createClassType(
 444     DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
 445     uint64_t SizeInBits, uint32_t AlignInBits, uint64_t OffsetInBits,
 446     DINode::DIFlags Flags, DIType *DerivedFrom, DINodeArray Elements,
 447     DIType *VTableHolder, MDNode *TemplateParams, StringRef UniqueIdentifier) {
 448   assert((!Context || isa<DIScope>(Context)) &&
 449          "createClassType should be called with a valid Context");
 450
 451   auto *R = DICompositeType::get(
 452       VMContext, dwarf::DW_TAG_structure_type, Name, File, LineNumber,
 453       getNonCompileUnitScope(Context), DerivedFrom, SizeInBits, AlignInBits,
 454       OffsetInBits, Flags, Elements, 0, VTableHolder,
 455       cast_or_null<MDTuple>(TemplateParams), UniqueIdentifier);
 456   trackIfUnresolved(R);
 457   return R;
 458 }
 459
 460 DICompositeType *DIBuilder::createStructType(
 461     DIScope *Context, StringRef Name, DIFile *File, unsigned LineNumber,
 462     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
 463     DIType *DerivedFrom, DINodeArray Elements, unsigned RunTimeLang,
 464     DIType *VTableHolder, StringRef UniqueIdentifier) {
 465   auto *R = DICompositeType::get(
 466       VMContext, dwarf::DW_TAG_structure_type, Name, File, LineNumber,
 467       getNonCompileUnitScope(Context), DerivedFrom, SizeInBits, AlignInBits, 0,
 468       Flags, Elements, RunTimeLang, VTableHolder, nullptr, UniqueIdentifier);
 469   trackIfUnresolved(R);
 470   return R;
 471 }
 472
 473 DICompositeType *DIBuilder::createUnionType(
 474     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
 475     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
 476     DINodeArray Elements, unsigned RunTimeLang, StringRef UniqueIdentifier) {
 477   auto *R = DICompositeType::get(
 478       VMContext, dwarf::DW_TAG_union_type, Name, File, LineNumber,
 479       getNonCompileUnitScope(Scope), nullptr, SizeInBits, AlignInBits, 0, Flags,
 480       Elements, RunTimeLang, nullptr, nullptr, UniqueIdentifier);
 481   trackIfUnresolved(R);
 482   return R;
 483 }
 484
 485 DICompositeType *DIBuilder::createVariantPart(
 486     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
 487     uint64_t SizeInBits, uint32_t AlignInBits, DINode::DIFlags Flags,
 488     DIDerivedType *Discriminator, DINodeArray Elements, StringRef UniqueIdentifier) {
 489   auto *R = DICompositeType::get(
 490       VMContext, dwarf::DW_TAG_variant_part, Name, File, LineNumber,
 491       getNonCompileUnitScope(Scope), nullptr, SizeInBits, AlignInBits, 0, Flags,
 492       Elements, 0, nullptr, nullptr, UniqueIdentifier, Discriminator);
 493   trackIfUnresolved(R);
 494   return R;
 495 }
 496
 497 DISubroutineType *DIBuilder::createSubroutineType(DITypeRefArray ParameterTypes,
 498                                                   DINode::DIFlags Flags,
 499                                                   unsigned CC) {
 500   return DISubroutineType::get(VMContext, Flags, CC, ParameterTypes);
 501 }
 502
 503 DICompositeType *DIBuilder::createEnumerationType(
 504     DIScope *Scope, StringRef Name, DIFile *File, unsigned LineNumber,
 505     uint64_t SizeInBits, uint32_t AlignInBits, DINodeArray Elements,
 506     DIType *UnderlyingType, StringRef UniqueIdentifier, bool IsScoped) {
 507   auto *CTy = DICompositeType::get(
 508       VMContext, dwarf::DW_TAG_enumeration_type, Name, File, LineNumber,
 509       getNonCompileUnitScope(Scope), UnderlyingType, SizeInBits, AlignInBits, 0,
 510       IsScoped ? DINode::FlagEnumClass : DINode::FlagZero, Elements, 0, nullptr,
 511       nullptr, UniqueIdentifier);
 512   AllEnumTypes.push_back(CTy);
 513   trackIfUnresolved(CTy);
 514   return CTy;
 515 }
 516
 517 DICompositeType *DIBuilder::createArrayType(uint64_t Size,
 518                                             uint32_t AlignInBits, DIType *Ty,
 519                                             DINodeArray Subscripts) {
 520   auto *R = DICompositeType::get(VMContext, dwarf::DW_TAG_array_type, "",
 521                                  nullptr, 0, nullptr, Ty, Size, AlignInBits, 0,
 522                                  DINode::FlagZero, Subscripts, 0, nullptr);
 523   trackIfUnresolved(R);
 524   return R;
 525 }
 526
 527 DICompositeType *DIBuilder::createVectorType(uint64_t Size,
 528                                              uint32_t AlignInBits, DIType *Ty,
 529                                              DINodeArray Subscripts) {
 530   auto *R = DICompositeType::get(VMContext, dwarf::DW_TAG_array_type, "",
 531                                  nullptr, 0, nullptr, Ty, Size, AlignInBits, 0,
 532                                  DINode::FlagVector, Subscripts, 0, nullptr);
 533   trackIfUnresolved(R);
 534   return R;
 535 }
 536
 537 DISubprogram *DIBuilder::createArtificialSubprogram(DISubprogram *SP) {
 538   auto NewSP = SP->cloneWithFlags(SP->getFlags() | DINode::FlagArtificial);
 539   return MDNode::replaceWithDistinct(std::move(NewSP));
 540 }
 541
 542 static DIType *createTypeWithFlags(const DIType *Ty,
 543                                    DINode::DIFlags FlagsToSet) {
 544   auto NewTy = Ty->cloneWithFlags(Ty->getFlags() | FlagsToSet);
 545   return MDNode::replaceWithUniqued(std::move(NewTy));
 546 }
 547
 548 DIType *DIBuilder::createArtificialType(DIType *Ty) {
 549   // FIXME: Restrict this to the nodes where it's valid.
 550   if (Ty->isArtificial())
 551     return Ty;
 552   return createTypeWithFlags(Ty, DINode::FlagArtificial);
 553 }
 554
 555 DIType *DIBuilder::createObjectPointerType(DIType *Ty) {
 556   // FIXME: Restrict this to the nodes where it's valid.
 557   if (Ty->isObjectPointer())
 558     return Ty;
 559   DINode::DIFlags Flags = DINode::FlagObjectPointer | DINode::FlagArtificial;
 560   return createTypeWithFlags(Ty, Flags);
 561 }
 562
 563 void DIBuilder::retainType(DIScope *T) {
 564   assert(T && "Expected non-null type");
 565   assert((isa<DIType>(T) || (isa<DISubprogram>(T) &&
 566                              cast<DISubprogram>(T)->isDefinition() == false)) &&
 567          "Expected type or subprogram declaration");
 568   AllRetainTypes.emplace_back(T);
 569 }
 570
 571 DIBasicType *DIBuilder::createUnspecifiedParameter() { return nullptr; }
 572
 573 DICompositeType *
 574 DIBuilder::createForwardDecl(unsigned Tag, StringRef Name, DIScope *Scope,
 575                              DIFile *F, unsigned Line, unsigned RuntimeLang,
 576                              uint64_t SizeInBits, uint32_t AlignInBits,
 577                              StringRef UniqueIdentifier) {
 578   // FIXME: Define in terms of createReplaceableForwardDecl() by calling
 579   // replaceWithUniqued().
 580   auto *RetTy = DICompositeType::get(
 581       VMContext, Tag, Name, F, Line, getNonCompileUnitScope(Scope), nullptr,
 582       SizeInBits, AlignInBits, 0, DINode::FlagFwdDecl, nullptr, RuntimeLang,
 583       nullptr, nullptr, UniqueIdentifier);
 584   trackIfUnresolved(RetTy);
 585   return RetTy;
 586 }
 587
 588 DICompositeType *DIBuilder::createReplaceableCompositeType(
 589     unsigned Tag, StringRef Name, DIScope *Scope, DIFile *F, unsigned Line,
 590     unsigned RuntimeLang, uint64_t SizeInBits, uint32_t AlignInBits,
 591     DINode::DIFlags Flags, StringRef UniqueIdentifier) {
 592   auto *RetTy =
 593       DICompositeType::getTemporary(
 594           VMContext, Tag, Name, F, Line, getNonCompileUnitScope(Scope), nullptr,
 595           SizeInBits, AlignInBits, 0, Flags, nullptr, RuntimeLang, nullptr,
 596           nullptr, UniqueIdentifier)
 597           .release();
 598   trackIfUnresolved(RetTy);
 599   return RetTy;
 600 }
 601
 602 DINodeArray DIBuilder::getOrCreateArray(ArrayRef<Metadata *> Elements) {
 603   return MDTuple::get(VMContext, Elements);
 604 }
 605
 606 DIMacroNodeArray
 607 DIBuilder::getOrCreateMacroArray(ArrayRef<Metadata *> Elements) {
 608   return MDTuple::get(VMContext, Elements);
 609 }
 610
 611 DITypeRefArray DIBuilder::getOrCreateTypeArray(ArrayRef<Metadata *> Elements) {
 612   SmallVector<llvm::Metadata *, 16> Elts;
 613   for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
 614     if (Elements[i] && isa<MDNode>(Elements[i]))
 615       Elts.push_back(cast<DIType>(Elements[i]));
 616     else
 617       Elts.push_back(Elements[i]);
 618   }
 619   return DITypeRefArray(MDNode::get(VMContext, Elts));
 620 }
 621
 622 DISubrange *DIBuilder::getOrCreateSubrange(int64_t Lo, int64_t Count) {
 623   return DISubrange::get(VMContext, Count, Lo);
 624 }
 625
 626 DISubrange *DIBuilder::getOrCreateSubrange(int64_t Lo, Metadata *CountNode) {
 627   return DISubrange::get(VMContext, CountNode, Lo);
 628 }
 629
 630 static void checkGlobalVariableScope(DIScope *Context) {
 631 #ifndef NDEBUG
 632   if (auto *CT =
 633           dyn_cast_or_null<DICompositeType>(getNonCompileUnitScope(Context)))
 634     assert(CT->getIdentifier().empty() &&
 635            "Context of a global variable should not be a type with identifier");
 636 #endif
 637 }
 638
 639 DIGlobalVariableExpression *DIBuilder::createGlobalVariableExpression(
 640     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
 641     unsigned LineNumber, DIType *Ty, bool isLocalToUnit, DIExpression *Expr,
 642     MDNode *Decl, MDTuple *templateParams, uint32_t AlignInBits) {
 643   checkGlobalVariableScope(Context);
 644
 645   auto *GV = DIGlobalVariable::getDistinct(
 646       VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
 647       LineNumber, Ty, isLocalToUnit, true, cast_or_null<DIDerivedType>(Decl),
 648       templateParams, AlignInBits);
 649   if (!Expr)
 650     Expr = createExpression();
 651   auto *N = DIGlobalVariableExpression::get(VMContext, GV, Expr);
 652   AllGVs.push_back(N);
 653   return N;
 654 }
 655
 656 DIGlobalVariable *DIBuilder::createTempGlobalVariableFwdDecl(
 657     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
 658     unsigned LineNumber, DIType *Ty, bool isLocalToUnit, MDNode *Decl,
 659     MDTuple *templateParams, uint32_t AlignInBits) {
 660   checkGlobalVariableScope(Context);
 661
 662   return DIGlobalVariable::getTemporary(
 663              VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
 664              LineNumber, Ty, isLocalToUnit, false,
 665              cast_or_null<DIDerivedType>(Decl), templateParams, AlignInBits)
 666       .release();
 667 }
 668
 669 static DILocalVariable *createLocalVariable(
 670     LLVMContext &VMContext,
 671     DenseMap<MDNode *, SmallVector<TrackingMDNodeRef, 1>> &PreservedVariables,
 672     DIScope *Scope, StringRef Name, unsigned ArgNo, DIFile *File,
 673     unsigned LineNo, DIType *Ty, bool AlwaysPreserve, DINode::DIFlags Flags,
 674     uint32_t AlignInBits) {
 675   // FIXME: Why getNonCompileUnitScope()?
 676   // FIXME: Why is "!Context" okay here?
 677   // FIXME: Why doesn't this check for a subprogram or lexical block (AFAICT
 678   // the only valid scopes)?
 679   DIScope *Context = getNonCompileUnitScope(Scope);
 680
 681   auto *Node =
 682       DILocalVariable::get(VMContext, cast_or_null<DILocalScope>(Context), Name,
 683                            File, LineNo, Ty, ArgNo, Flags, AlignInBits);
 684   if (AlwaysPreserve) {
 685     // The optimizer may remove local variables. If there is an interest
 686     // to preserve variable info in such situation then stash it in a
 687     // named mdnode.
 688     DISubprogram *Fn = getDISubprogram(Scope);
 689     assert(Fn && "Missing subprogram for local variable");
 690     PreservedVariables[Fn].emplace_back(Node);
 691   }
 692   return Node;
 693 }
 694
 695 DILocalVariable *DIBuilder::createAutoVariable(DIScope *Scope, StringRef Name,
 696                                                DIFile *File, unsigned LineNo,
 697                                                DIType *Ty, bool AlwaysPreserve,
 698                                                DINode::DIFlags Flags,
 699                                                uint32_t AlignInBits) {
 700   return createLocalVariable(VMContext, PreservedVariables, Scope, Name,
 701                              /* ArgNo */ 0, File, LineNo, Ty, AlwaysPreserve,
 702                              Flags, AlignInBits);
 703 }
 704
 705 DILocalVariable *DIBuilder::createParameterVariable(
 706     DIScope *Scope, StringRef Name, unsigned ArgNo, DIFile *File,
 707     unsigned LineNo, DIType *Ty, bool AlwaysPreserve, DINode::DIFlags Flags) {
 708   assert(ArgNo && "Expected non-zero argument number for parameter");
 709   return createLocalVariable(VMContext, PreservedVariables, Scope, Name, ArgNo,
 710                              File, LineNo, Ty, AlwaysPreserve, Flags,
 711                              /* AlignInBits */0);
 712 }
 713
 714 DILabel *DIBuilder::createLabel(
 715     DIScope *Scope, StringRef Name, DIFile *File,
 716     unsigned LineNo, bool AlwaysPreserve) {
 717   DIScope *Context = getNonCompileUnitScope(Scope);
 718
 719   auto *Node =
 720       DILabel::get(VMContext, cast_or_null<DILocalScope>(Context), Name,
 721                    File, LineNo);
 722
 723   if (AlwaysPreserve) {
 724     /// The optimizer may remove labels. If there is an interest
 725     /// to preserve label info in such situation then append it to
 726     /// the list of retained nodes of the DISubprogram.
 727     DISubprogram *Fn = getDISubprogram(Scope);
 728     assert(Fn && "Missing subprogram for label");
 729     PreservedLabels[Fn].emplace_back(Node);
 730   }
 731   return Node;
 732 }
 733
 734 DIExpression *DIBuilder::createExpression(ArrayRef<uint64_t> Addr) {
 735   return DIExpression::get(VMContext, Addr);
 736 }
 737
 738 DIExpression *DIBuilder::createExpression(ArrayRef<int64_t> Signed) {
 739   // TODO: Remove the callers of this signed version and delete.
 740   SmallVector<uint64_t, 8> Addr(Signed.begin(), Signed.end());
 741   return createExpression(Addr);
 742 }
 743
 744 template <class... Ts>
 745 static DISubprogram *getSubprogram(bool IsDistinct, Ts &&... Args) {
 746   if (IsDistinct)
 747     return DISubprogram::getDistinct(std::forward<Ts>(Args)...);
 748   return DISubprogram::get(std::forward<Ts>(Args)...);
 749 }
 750
 751 DISubprogram *DIBuilder::createFunction(
 752     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
 753     unsigned LineNo, DISubroutineType *Ty, unsigned ScopeLine,
 754     DINode::DIFlags Flags, DISubprogram::DISPFlags SPFlags,
 755     DITemplateParameterArray TParams, DISubprogram *Decl,
 756     DITypeArray ThrownTypes) {
 757   bool IsDefinition = SPFlags & DISubprogram::SPFlagDefinition;
 758   auto *Node = getSubprogram(
 759       /*IsDistinct=*/IsDefinition, VMContext, getNonCompileUnitScope(Context),
 760       Name, LinkageName, File, LineNo, Ty, ScopeLine, nullptr, 0, 0, Flags,
 761       SPFlags, IsDefinition ? CUNode : nullptr, TParams, Decl,
 762       MDTuple::getTemporary(VMContext, None).release(), ThrownTypes);
 763
 764   if (IsDefinition)
 765     AllSubprograms.push_back(Node);
 766   trackIfUnresolved(Node);
 767   return Node;
 768 }
 769
 770 DISubprogram *DIBuilder::createTempFunctionFwdDecl(
 771     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
 772     unsigned LineNo, DISubroutineType *Ty, unsigned ScopeLine,
 773     DINode::DIFlags Flags, DISubprogram::DISPFlags SPFlags,
 774     DITemplateParameterArray TParams, DISubprogram *Decl,
 775     DITypeArray ThrownTypes) {
 776   bool IsDefinition = SPFlags & DISubprogram::SPFlagDefinition;
 777   return DISubprogram::getTemporary(VMContext, getNonCompileUnitScope(Context),
 778                                     Name, LinkageName, File, LineNo, Ty,
 779                                     ScopeLine, nullptr, 0, 0, Flags, SPFlags,
 780                                     IsDefinition ? CUNode : nullptr, TParams,
 781                                     Decl, nullptr, ThrownTypes)
 782       .release();
 783 }
 784
 785 DISubprogram *DIBuilder::createMethod(
 786     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
 787     unsigned LineNo, DISubroutineType *Ty, unsigned VIndex, int ThisAdjustment,
 788     DIType *VTableHolder, DINode::DIFlags Flags,
 789     DISubprogram::DISPFlags SPFlags, DITemplateParameterArray TParams,
 790     DITypeArray ThrownTypes) {
 791   assert(getNonCompileUnitScope(Context) &&
 792          "Methods should have both a Context and a context that isn't "
 793          "the compile unit.");
 794   // FIXME: Do we want to use different scope/lines?
 795   bool IsDefinition = SPFlags & DISubprogram::SPFlagDefinition;
 796   auto *SP = getSubprogram(
 797       /*IsDistinct=*/IsDefinition, VMContext, cast<DIScope>(Context), Name,
 798       LinkageName, F, LineNo, Ty, LineNo, VTableHolder, VIndex, ThisAdjustment,
 799       Flags, SPFlags, IsDefinition ? CUNode : nullptr, TParams, nullptr,
 800       nullptr, ThrownTypes);
 801
 802   if (IsDefinition)
 803     AllSubprograms.push_back(SP);
 804   trackIfUnresolved(SP);
 805   return SP;
 806 }
 807
 808 DICommonBlock *DIBuilder::createCommonBlock(
 809     DIScope *Scope, DIGlobalVariable *Decl, StringRef Name, DIFile *File,
 810     unsigned LineNo) {
 811   return DICommonBlock::get(
 812       VMContext, Scope, Decl, Name, File, LineNo);
 813 }
 814
 815 DINamespace *DIBuilder::createNameSpace(DIScope *Scope, StringRef Name,
 816                                         bool ExportSymbols) {
 817
 818   // It is okay to *not* make anonymous top-level namespaces distinct, because
 819   // all nodes that have an anonymous namespace as their parent scope are
 820   // guaranteed to be unique and/or are linked to their containing
 821   // DICompileUnit. This decision is an explicit tradeoff of link time versus
 822   // memory usage versus code simplicity and may get revisited in the future.
 823   return DINamespace::get(VMContext, getNonCompileUnitScope(Scope), Name,
 824                           ExportSymbols);
 825 }
 826
 827 DIModule *DIBuilder::createModule(DIScope *Scope, StringRef Name,
 828                                   StringRef ConfigurationMacros,
 829                                   StringRef IncludePath,
 830                                   StringRef ISysRoot) {
 831  return DIModule::get(VMContext, getNonCompileUnitScope(Scope), Name,
 832                       ConfigurationMacros, IncludePath, ISysRoot);
 833 }
 834
 835 DILexicalBlockFile *DIBuilder::createLexicalBlockFile(DIScope *Scope,
 836                                                       DIFile *File,
 837                                                       unsigned Discriminator) {
 838   return DILexicalBlockFile::get(VMContext, Scope, File, Discriminator);
 839 }
 840
 841 DILexicalBlock *DIBuilder::createLexicalBlock(DIScope *Scope, DIFile *File,
 842                                               unsigned Line, unsigned Col) {
 843   // Make these distinct, to avoid merging two lexical blocks on the same
 844   // file/line/column.
 845   return DILexicalBlock::getDistinct(VMContext, getNonCompileUnitScope(Scope),
 846                                      File, Line, Col);
 847 }
 848
 849 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
 850                                       DIExpression *Expr, const DILocation *DL,
 851                                       Instruction *InsertBefore) {
 852   return insertDeclare(Storage, VarInfo, Expr, DL, InsertBefore->getParent(),
 853                        InsertBefore);
 854 }
 855
 856 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
 857                                       DIExpression *Expr, const DILocation *DL,
 858                                       BasicBlock *InsertAtEnd) {
 859   // If this block already has a terminator then insert this intrinsic before
 860   // the terminator. Otherwise, put it at the end of the block.
 861   Instruction *InsertBefore = InsertAtEnd->getTerminator();
 862   return insertDeclare(Storage, VarInfo, Expr, DL, InsertAtEnd, InsertBefore);
 863 }
 864
 865 Instruction *DIBuilder::insertLabel(DILabel *LabelInfo, const DILocation *DL,
 866                                     Instruction *InsertBefore) {
 867   return insertLabel(
 868       LabelInfo, DL, InsertBefore ? InsertBefore->getParent() : nullptr,
 869       InsertBefore);
 870 }
 871
 872 Instruction *DIBuilder::insertLabel(DILabel *LabelInfo, const DILocation *DL,
 873                                     BasicBlock *InsertAtEnd) {
 874   return insertLabel(LabelInfo, DL, InsertAtEnd, nullptr);
 875 }
 876
 877 Instruction *DIBuilder::insertDbgValueIntrinsic(Value *V,
 878                                                 DILocalVariable *VarInfo,
 879                                                 DIExpression *Expr,
 880                                                 const DILocation *DL,
 881                                                 Instruction *InsertBefore) {
 882   return insertDbgValueIntrinsic(
 883       V, VarInfo, Expr, DL, InsertBefore ? InsertBefore->getParent() : nullptr,
 884       InsertBefore);
 885 }
 886
 887 Instruction *DIBuilder::insertDbgValueIntrinsic(Value *V,
 888                                                 DILocalVariable *VarInfo,
 889                                                 DIExpression *Expr,
 890                                                 const DILocation *DL,
 891                                                 BasicBlock *InsertAtEnd) {
 892   return insertDbgValueIntrinsic(V, VarInfo, Expr, DL, InsertAtEnd, nullptr);
 893 }
 894
 895 /// Return an IRBuilder for inserting dbg.declare and dbg.value intrinsics. This
 896 /// abstracts over the various ways to specify an insert position.
 897 static IRBuilder<> getIRBForDbgInsertion(const DILocation *DL,
 898                                          BasicBlock *InsertBB,
 899                                          Instruction *InsertBefore) {
 900   IRBuilder<> B(DL->getContext());
 901   if (InsertBefore)
 902     B.SetInsertPoint(InsertBefore);
 903   else if (InsertBB)
 904     B.SetInsertPoint(InsertBB);
 905   B.SetCurrentDebugLocation(DL);
 906   return B;
 907 }
 908
 909 static Value *getDbgIntrinsicValueImpl(LLVMContext &VMContext, Value *V) {
 910   assert(V && "no value passed to dbg intrinsic");
 911   return MetadataAsValue::get(VMContext, ValueAsMetadata::get(V));
 912 }
 913
 914 static Function *getDeclareIntrin(Module &M) {
 915   return Intrinsic::getDeclaration(&M, UseDbgAddr ? Intrinsic::dbg_addr
 916                                                   : Intrinsic::dbg_declare);
 917 }
 918
 919 Instruction *DIBuilder::insertDeclare(Value *Storage, DILocalVariable *VarInfo,
 920                                       DIExpression *Expr, const DILocation *DL,
 921                                       BasicBlock *InsertBB, Instruction *InsertBefore) {
 922   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.declare");
 923   assert(DL && "Expected debug loc");
 924   assert(DL->getScope()->getSubprogram() ==
 925              VarInfo->getScope()->getSubprogram() &&
 926          "Expected matching subprograms");
 927   if (!DeclareFn)
 928     DeclareFn = getDeclareIntrin(M);
 929
 930   trackIfUnresolved(VarInfo);
 931   trackIfUnresolved(Expr);
 932   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, Storage),
 933                    MetadataAsValue::get(VMContext, VarInfo),
 934                    MetadataAsValue::get(VMContext, Expr)};
 935
 936   IRBuilder<> B = getIRBForDbgInsertion(DL, InsertBB, InsertBefore);
 937   return B.CreateCall(DeclareFn, Args);
 938 }
 939
 940 Instruction *DIBuilder::insertDbgValueIntrinsic(
 941     Value *V, DILocalVariable *VarInfo, DIExpression *Expr,
 942     const DILocation *DL, BasicBlock *InsertBB, Instruction *InsertBefore) {
 943   assert(V && "no value passed to dbg.value");
 944   assert(VarInfo && "empty or invalid DILocalVariable* passed to dbg.value");
 945   assert(DL && "Expected debug loc");
 946   assert(DL->getScope()->getSubprogram() ==
 947              VarInfo->getScope()->getSubprogram() &&
 948          "Expected matching subprograms");
 949   if (!ValueFn)
 950     ValueFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_value);
 951
 952   trackIfUnresolved(VarInfo);
 953   trackIfUnresolved(Expr);
 954   Value *Args[] = {getDbgIntrinsicValueImpl(VMContext, V),
 955                    MetadataAsValue::get(VMContext, VarInfo),
 956                    MetadataAsValue::get(VMContext, Expr)};
 957
 958   IRBuilder<> B = getIRBForDbgInsertion(DL, InsertBB, InsertBefore);
 959   return B.CreateCall(ValueFn, Args);
 960 }
 961
 962 Instruction *DIBuilder::insertLabel(
 963     DILabel *LabelInfo, const DILocation *DL,
 964     BasicBlock *InsertBB, Instruction *InsertBefore) {
 965   assert(LabelInfo && "empty or invalid DILabel* passed to dbg.label");
 966   assert(DL && "Expected debug loc");
 967   assert(DL->getScope()->getSubprogram() ==
 968              LabelInfo->getScope()->getSubprogram() &&
 969          "Expected matching subprograms");
 970   if (!LabelFn)
 971     LabelFn = Intrinsic::getDeclaration(&M, Intrinsic::dbg_label);
 972
 973   trackIfUnresolved(LabelInfo);
 974   Value *Args[] = {MetadataAsValue::get(VMContext, LabelInfo)};
 975
 976   IRBuilder<> B = getIRBForDbgInsertion(DL, InsertBB, InsertBefore);
 977   return B.CreateCall(LabelFn, Args);
 978 }
 979
 980 void DIBuilder::replaceVTableHolder(DICompositeType *&T,
 981                                     DIType *VTableHolder) {
 982   {
 983     TypedTrackingMDRef<DICompositeType> N(T);
 984     N->replaceVTableHolder(VTableHolder);
 985     T = N.get();
 986   }
 987
 988   // If this didn't create a self-reference, just return.
 989   if (T != VTableHolder)
 990     return;
 991
 992   // Look for unresolved operands.  T will drop RAUW support, orphaning any
 993   // cycles underneath it.
 994   if (T->isResolved())
 995     for (const MDOperand &O : T->operands())
 996       if (auto *N = dyn_cast_or_null<MDNode>(O))
 997         trackIfUnresolved(N);
 998 }
 999
1000 void DIBuilder::replaceArrays(DICompositeType *&T, DINodeArray Elements,
1001                               DINodeArray TParams) {
1002   {
1003     TypedTrackingMDRef<DICompositeType> N(T);
1004     if (Elements)
1005       N->replaceElements(Elements);
1006     if (TParams)
1007       N->replaceTemplateParams(DITemplateParameterArray(TParams));
1008     T = N.get();
1009   }
1010
1011   // If T isn't resolved, there's no problem.
1012   if (!T->isResolved())
1013     return;
1014
1015   // If T is resolved, it may be due to a self-reference cycle.  Track the
1016   // arrays explicitly if they're unresolved, or else the cycles will be
1017   // orphaned.
1018   if (Elements)
1019     trackIfUnresolved(Elements.get());
1020   if (TParams)
1021     trackIfUnresolved(TParams.get());
1022 }