lib/IR/DIBuilder.cpp

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