llvm/lib/IR/Globals.cpp

   1 //===-- Globals.cpp - Implement the GlobalValue & GlobalVariable class ----===//
   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 GlobalValue & GlobalVariable classes for the IR
  10 // library.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "LLVMContextImpl.h"
  15 #include "llvm/IR/ConstantRange.h"
  16 #include "llvm/IR/Constants.h"
  17 #include "llvm/IR/DerivedTypes.h"
  18 #include "llvm/IR/GlobalAlias.h"
  19 #include "llvm/IR/GlobalValue.h"
  20 #include "llvm/IR/GlobalVariable.h"
  21 #include "llvm/IR/Module.h"
  22 #include "llvm/Support/Error.h"
  23 #include "llvm/Support/ErrorHandling.h"
  24 #include "llvm/TargetParser/Triple.h"
  25 using namespace llvm;
  26
  27 //===----------------------------------------------------------------------===//
  28 //                            GlobalValue Class
  29 //===----------------------------------------------------------------------===//
  30
  31 // GlobalValue should be a Constant, plus a type, a module, some flags, and an
  32 // intrinsic ID. Add an assert to prevent people from accidentally growing
  33 // GlobalValue while adding flags.
  34 static_assert(sizeof(GlobalValue) ==
  35                   sizeof(Constant) + 2 * sizeof(void *) + 2 * sizeof(unsigned),
  36               "unexpected GlobalValue size growth");
  37
  38 // GlobalObject adds a comdat.
  39 static_assert(sizeof(GlobalObject) == sizeof(GlobalValue) + sizeof(void *),
  40               "unexpected GlobalObject size growth");
  41
  42 bool GlobalValue::isMaterializable() const {
  43   if (const Function *F = dyn_cast<Function>(this))
  44     return F->isMaterializable();
  45   return false;
  46 }
  47 Error GlobalValue::materialize() { return getParent()->materialize(this); }
  48
  49 /// Override destroyConstantImpl to make sure it doesn't get called on
  50 /// GlobalValue's because they shouldn't be treated like other constants.
  51 void GlobalValue::destroyConstantImpl() {
  52   llvm_unreachable("You can't GV->destroyConstantImpl()!");
  53 }
  54
  55 Value *GlobalValue::handleOperandChangeImpl(Value *From, Value *To) {
  56   llvm_unreachable("Unsupported class for handleOperandChange()!");
  57 }
  58
  59 /// copyAttributesFrom - copy all additional attributes (those not needed to
  60 /// create a GlobalValue) from the GlobalValue Src to this one.
  61 void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
  62   setVisibility(Src->getVisibility());
  63   setUnnamedAddr(Src->getUnnamedAddr());
  64   setThreadLocalMode(Src->getThreadLocalMode());
  65   setDLLStorageClass(Src->getDLLStorageClass());
  66   setDSOLocal(Src->isDSOLocal());
  67   setPartition(Src->getPartition());
  68   if (Src->hasSanitizerMetadata())
  69     setSanitizerMetadata(Src->getSanitizerMetadata());
  70   else
  71     removeSanitizerMetadata();
  72 }
  73
  74 void GlobalValue::removeFromParent() {
  75   switch (getValueID()) {
  76 #define HANDLE_GLOBAL_VALUE(NAME)                                              \
  77   case Value::NAME##Val:                                                       \
  78     return static_cast<NAME *>(this)->removeFromParent();
  79 #include "llvm/IR/Value.def"
  80   default:
  81     break;
  82   }
  83   llvm_unreachable("not a global");
  84 }
  85
  86 void GlobalValue::eraseFromParent() {
  87   switch (getValueID()) {
  88 #define HANDLE_GLOBAL_VALUE(NAME)                                              \
  89   case Value::NAME##Val:                                                       \
  90     return static_cast<NAME *>(this)->eraseFromParent();
  91 #include "llvm/IR/Value.def"
  92   default:
  93     break;
  94   }
  95   llvm_unreachable("not a global");
  96 }
  97
  98 GlobalObject::~GlobalObject() { setComdat(nullptr); }
  99
 100 bool GlobalValue::isInterposable() const {
 101   if (isInterposableLinkage(getLinkage()))
 102     return true;
 103   return getParent() && getParent()->getSemanticInterposition() &&
 104          !isDSOLocal();
 105 }
 106
 107 bool GlobalValue::canBenefitFromLocalAlias() const {
 108   // See AsmPrinter::getSymbolPreferLocal(). For a deduplicate comdat kind,
 109   // references to a discarded local symbol from outside the group are not
 110   // allowed, so avoid the local alias.
 111   auto isDeduplicateComdat = [](const Comdat *C) {
 112     return C && C->getSelectionKind() != Comdat::NoDeduplicate;
 113   };
 114   return hasDefaultVisibility() &&
 115          GlobalObject::isExternalLinkage(getLinkage()) && !isDeclaration() &&
 116          !isa<GlobalIFunc>(this) && !isDeduplicateComdat(getComdat());
 117 }
 118
 119 void GlobalObject::setAlignment(MaybeAlign Align) {
 120   assert((!Align || *Align <= MaximumAlignment) &&
 121          "Alignment is greater than MaximumAlignment!");
 122   unsigned AlignmentData = encode(Align);
 123   unsigned OldData = getGlobalValueSubClassData();
 124   setGlobalValueSubClassData((OldData & ~AlignmentMask) | AlignmentData);
 125   assert(getAlign() == Align && "Alignment representation error!");
 126 }
 127
 128 void GlobalObject::setAlignment(Align Align) {
 129   assert(Align <= MaximumAlignment &&
 130          "Alignment is greater than MaximumAlignment!");
 131   unsigned AlignmentData = encode(Align);
 132   unsigned OldData = getGlobalValueSubClassData();
 133   setGlobalValueSubClassData((OldData & ~AlignmentMask) | AlignmentData);
 134   assert(getAlign() && *getAlign() == Align &&
 135          "Alignment representation error!");
 136 }
 137
 138 void GlobalObject::copyAttributesFrom(const GlobalObject *Src) {
 139   GlobalValue::copyAttributesFrom(Src);
 140   setAlignment(Src->getAlign());
 141   setSection(Src->getSection());
 142 }
 143
 144 std::string GlobalValue::getGlobalIdentifier(StringRef Name,
 145                                              GlobalValue::LinkageTypes Linkage,
 146                                              StringRef FileName) {
 147   // Value names may be prefixed with a binary '1' to indicate
 148   // that the backend should not modify the symbols due to any platform
 149   // naming convention. Do not include that '1' in the PGO profile name.
 150   Name.consume_front("\1");
 151
 152   std::string GlobalName;
 153   if (llvm::GlobalValue::isLocalLinkage(Linkage)) {
 154     // For local symbols, prepend the main file name to distinguish them.
 155     // Do not include the full path in the file name since there's no guarantee
 156     // that it will stay the same, e.g., if the files are checked out from
 157     // version control in different locations.
 158     if (FileName.empty())
 159       GlobalName += "<unknown>";
 160     else
 161       GlobalName += FileName;
 162
 163     GlobalName += kGlobalIdentifierDelimiter;
 164   }
 165   GlobalName += Name;
 166   return GlobalName;
 167 }
 168
 169 std::string GlobalValue::getGlobalIdentifier() const {
 170   return getGlobalIdentifier(getName(), getLinkage(),
 171                              getParent()->getSourceFileName());
 172 }
 173
 174 StringRef GlobalValue::getSection() const {
 175   if (auto *GA = dyn_cast<GlobalAlias>(this)) {
 176     // In general we cannot compute this at the IR level, but we try.
 177     if (const GlobalObject *GO = GA->getAliaseeObject())
 178       return GO->getSection();
 179     return "";
 180   }
 181   return cast<GlobalObject>(this)->getSection();
 182 }
 183
 184 const Comdat *GlobalValue::getComdat() const {
 185   if (auto *GA = dyn_cast<GlobalAlias>(this)) {
 186     // In general we cannot compute this at the IR level, but we try.
 187     if (const GlobalObject *GO = GA->getAliaseeObject())
 188       return const_cast<GlobalObject *>(GO)->getComdat();
 189     return nullptr;
 190   }
 191   // ifunc and its resolver are separate things so don't use resolver comdat.
 192   if (isa<GlobalIFunc>(this))
 193     return nullptr;
 194   return cast<GlobalObject>(this)->getComdat();
 195 }
 196
 197 void GlobalObject::setComdat(Comdat *C) {
 198   if (ObjComdat)
 199     ObjComdat->removeUser(this);
 200   ObjComdat = C;
 201   if (C)
 202     C->addUser(this);
 203 }
 204
 205 StringRef GlobalValue::getPartition() const {
 206   if (!hasPartition())
 207     return "";
 208   return getContext().pImpl->GlobalValuePartitions[this];
 209 }
 210
 211 void GlobalValue::setPartition(StringRef S) {
 212   // Do nothing if we're clearing the partition and it is already empty.
 213   if (!hasPartition() && S.empty())
 214     return;
 215
 216   // Get or create a stable partition name string and put it in the table in the
 217   // context.
 218   if (!S.empty())
 219     S = getContext().pImpl->Saver.save(S);
 220   getContext().pImpl->GlobalValuePartitions[this] = S;
 221
 222   // Update the HasPartition field. Setting the partition to the empty string
 223   // means this global no longer has a partition.
 224   HasPartition = !S.empty();
 225 }
 226
 227 using SanitizerMetadata = GlobalValue::SanitizerMetadata;
 228 const SanitizerMetadata &GlobalValue::getSanitizerMetadata() const {
 229   assert(hasSanitizerMetadata());
 230   assert(getContext().pImpl->GlobalValueSanitizerMetadata.count(this));
 231   return getContext().pImpl->GlobalValueSanitizerMetadata[this];
 232 }
 233
 234 void GlobalValue::setSanitizerMetadata(SanitizerMetadata Meta) {
 235   getContext().pImpl->GlobalValueSanitizerMetadata[this] = Meta;
 236   HasSanitizerMetadata = true;
 237 }
 238
 239 void GlobalValue::removeSanitizerMetadata() {
 240   DenseMap<const GlobalValue *, SanitizerMetadata> &MetadataMap =
 241       getContext().pImpl->GlobalValueSanitizerMetadata;
 242   MetadataMap.erase(this);
 243   HasSanitizerMetadata = false;
 244 }
 245
 246 StringRef GlobalObject::getSectionImpl() const {
 247   assert(hasSection());
 248   return getContext().pImpl->GlobalObjectSections[this];
 249 }
 250
 251 void GlobalObject::setSection(StringRef S) {
 252   // Do nothing if we're clearing the section and it is already empty.
 253   if (!hasSection() && S.empty())
 254     return;
 255
 256   // Get or create a stable section name string and put it in the table in the
 257   // context.
 258   if (!S.empty())
 259     S = getContext().pImpl->Saver.save(S);
 260   getContext().pImpl->GlobalObjectSections[this] = S;
 261
 262   // Update the HasSectionHashEntryBit. Setting the section to the empty string
 263   // means this global no longer has a section.
 264   setGlobalObjectFlag(HasSectionHashEntryBit, !S.empty());
 265 }
 266
 267 bool GlobalValue::isNobuiltinFnDef() const {
 268   const Function *F = dyn_cast<Function>(this);
 269   if (!F || F->empty())
 270     return false;
 271   return F->hasFnAttribute(Attribute::NoBuiltin);
 272 }
 273
 274 bool GlobalValue::isDeclaration() const {
 275   // Globals are definitions if they have an initializer.
 276   if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(this))
 277     return GV->getNumOperands() == 0;
 278
 279   // Functions are definitions if they have a body.
 280   if (const Function *F = dyn_cast<Function>(this))
 281     return F->empty() && !F->isMaterializable();
 282
 283   // Aliases and ifuncs are always definitions.
 284   assert(isa<GlobalAlias>(this) || isa<GlobalIFunc>(this));
 285   return false;
 286 }
 287
 288 bool GlobalObject::canIncreaseAlignment() const {
 289   // Firstly, can only increase the alignment of a global if it
 290   // is a strong definition.
 291   if (!isStrongDefinitionForLinker())
 292     return false;
 293
 294   // It also has to either not have a section defined, or, not have
 295   // alignment specified. (If it is assigned a section, the global
 296   // could be densely packed with other objects in the section, and
 297   // increasing the alignment could cause padding issues.)
 298   if (hasSection() && getAlign())
 299     return false;
 300
 301   // On ELF platforms, we're further restricted in that we can't
 302   // increase the alignment of any variable which might be emitted
 303   // into a shared library, and which is exported. If the main
 304   // executable accesses a variable found in a shared-lib, the main
 305   // exe actually allocates memory for and exports the symbol ITSELF,
 306   // overriding the symbol found in the library. That is, at link
 307   // time, the observed alignment of the variable is copied into the
 308   // executable binary. (A COPY relocation is also generated, to copy
 309   // the initial data from the shadowed variable in the shared-lib
 310   // into the location in the main binary, before running code.)
 311   //
 312   // And thus, even though you might think you are defining the
 313   // global, and allocating the memory for the global in your object
 314   // file, and thus should be able to set the alignment arbitrarily,
 315   // that's not actually true. Doing so can cause an ABI breakage; an
 316   // executable might have already been built with the previous
 317   // alignment of the variable, and then assuming an increased
 318   // alignment will be incorrect.
 319
 320   // Conservatively assume ELF if there's no parent pointer.
 321   bool isELF =
 322       (!Parent || Triple(Parent->getTargetTriple()).isOSBinFormatELF());
 323   if (isELF && !isDSOLocal())
 324     return false;
 325
 326   return true;
 327 }
 328
 329 template <typename Operation>
 330 static const GlobalObject *
 331 findBaseObject(const Constant *C, DenseSet<const GlobalAlias *> &Aliases,
 332                const Operation &Op) {
 333   if (auto *GO = dyn_cast<GlobalObject>(C)) {
 334     Op(*GO);
 335     return GO;
 336   }
 337   if (auto *GA = dyn_cast<GlobalAlias>(C)) {
 338     Op(*GA);
 339     if (Aliases.insert(GA).second)
 340       return findBaseObject(GA->getOperand(0), Aliases, Op);
 341   }
 342   if (auto *CE = dyn_cast<ConstantExpr>(C)) {
 343     switch (CE->getOpcode()) {
 344     case Instruction::Add: {
 345       auto *LHS = findBaseObject(CE->getOperand(0), Aliases, Op);
 346       auto *RHS = findBaseObject(CE->getOperand(1), Aliases, Op);
 347       if (LHS && RHS)
 348         return nullptr;
 349       return LHS ? LHS : RHS;
 350     }
 351     case Instruction::Sub: {
 352       if (findBaseObject(CE->getOperand(1), Aliases, Op))
 353         return nullptr;
 354       return findBaseObject(CE->getOperand(0), Aliases, Op);
 355     }
 356     case Instruction::IntToPtr:
 357     case Instruction::PtrToInt:
 358     case Instruction::BitCast:
 359     case Instruction::GetElementPtr:
 360       return findBaseObject(CE->getOperand(0), Aliases, Op);
 361     default:
 362       break;
 363     }
 364   }
 365   return nullptr;
 366 }
 367
 368 const GlobalObject *GlobalValue::getAliaseeObject() const {
 369   DenseSet<const GlobalAlias *> Aliases;
 370   return findBaseObject(this, Aliases, [](const GlobalValue &) {});
 371 }
 372
 373 bool GlobalValue::isAbsoluteSymbolRef() const {
 374   auto *GO = dyn_cast<GlobalObject>(this);
 375   if (!GO)
 376     return false;
 377
 378   return GO->getMetadata(LLVMContext::MD_absolute_symbol);
 379 }
 380
 381 std::optional<ConstantRange> GlobalValue::getAbsoluteSymbolRange() const {
 382   auto *GO = dyn_cast<GlobalObject>(this);
 383   if (!GO)
 384     return std::nullopt;
 385
 386   MDNode *MD = GO->getMetadata(LLVMContext::MD_absolute_symbol);
 387   if (!MD)
 388     return std::nullopt;
 389
 390   return getConstantRangeFromMetadata(*MD);
 391 }
 392
 393 bool GlobalValue::canBeOmittedFromSymbolTable() const {
 394   if (!hasLinkOnceODRLinkage())
 395     return false;
 396
 397   // We assume that anyone who sets global unnamed_addr on a non-constant
 398   // knows what they're doing.
 399   if (hasGlobalUnnamedAddr())
 400     return true;
 401
 402   // If it is a non constant variable, it needs to be uniqued across shared
 403   // objects.
 404   if (auto *Var = dyn_cast<GlobalVariable>(this))
 405     if (!Var->isConstant())
 406       return false;
 407
 408   return hasAtLeastLocalUnnamedAddr();
 409 }
 410
 411 //===----------------------------------------------------------------------===//
 412 // GlobalVariable Implementation
 413 //===----------------------------------------------------------------------===//
 414
 415 GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
 416                                Constant *InitVal, const Twine &Name,
 417                                ThreadLocalMode TLMode, unsigned AddressSpace,
 418                                bool isExternallyInitialized)
 419     : GlobalObject(Ty, Value::GlobalVariableVal,
 420                    OperandTraits<GlobalVariable>::op_begin(this),
 421                    InitVal != nullptr, Link, Name, AddressSpace),
 422       isConstantGlobal(constant),
 423       isExternallyInitializedConstant(isExternallyInitialized) {
 424   assert(!Ty->isFunctionTy() && PointerType::isValidElementType(Ty) &&
 425          "invalid type for global variable");
 426   setThreadLocalMode(TLMode);
 427   if (InitVal) {
 428     assert(InitVal->getType() == Ty &&
 429            "Initializer should be the same type as the GlobalVariable!");
 430     Op<0>() = InitVal;
 431   }
 432 }
 433
 434 GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant,
 435                                LinkageTypes Link, Constant *InitVal,
 436                                const Twine &Name, GlobalVariable *Before,
 437                                ThreadLocalMode TLMode,
 438                                std::optional<unsigned> AddressSpace,
 439                                bool isExternallyInitialized)
 440     : GlobalVariable(Ty, constant, Link, InitVal, Name, TLMode,
 441                      AddressSpace
 442                          ? *AddressSpace
 443                          : M.getDataLayout().getDefaultGlobalsAddressSpace(),
 444                      isExternallyInitialized) {
 445   if (Before)
 446     Before->getParent()->insertGlobalVariable(Before->getIterator(), this);
 447   else
 448     M.insertGlobalVariable(this);
 449 }
 450
 451 void GlobalVariable::removeFromParent() {
 452   getParent()->removeGlobalVariable(this);
 453 }
 454
 455 void GlobalVariable::eraseFromParent() {
 456   getParent()->eraseGlobalVariable(this);
 457 }
 458
 459 void GlobalVariable::setInitializer(Constant *InitVal) {
 460   if (!InitVal) {
 461     if (hasInitializer()) {
 462       // Note, the num operands is used to compute the offset of the operand, so
 463       // the order here matters.  Clearing the operand then clearing the num
 464       // operands ensures we have the correct offset to the operand.
 465       Op<0>().set(nullptr);
 466       setGlobalVariableNumOperands(0);
 467     }
 468   } else {
 469     assert(InitVal->getType() == getValueType() &&
 470            "Initializer type must match GlobalVariable type");
 471     // Note, the num operands is used to compute the offset of the operand, so
 472     // the order here matters.  We need to set num operands to 1 first so that
 473     // we get the correct offset to the first operand when we set it.
 474     if (!hasInitializer())
 475       setGlobalVariableNumOperands(1);
 476     Op<0>().set(InitVal);
 477   }
 478 }
 479
 480 /// Copy all additional attributes (those not needed to create a GlobalVariable)
 481 /// from the GlobalVariable Src to this one.
 482 void GlobalVariable::copyAttributesFrom(const GlobalVariable *Src) {
 483   GlobalObject::copyAttributesFrom(Src);
 484   setExternallyInitialized(Src->isExternallyInitialized());
 485   setAttributes(Src->getAttributes());
 486   if (auto CM = Src->getCodeModel())
 487     setCodeModel(*CM);
 488 }
 489
 490 void GlobalVariable::dropAllReferences() {
 491   User::dropAllReferences();
 492   clearMetadata();
 493 }
 494
 495 void GlobalVariable::setCodeModel(CodeModel::Model CM) {
 496   unsigned CodeModelData = static_cast<unsigned>(CM) + 1;
 497   unsigned OldData = getGlobalValueSubClassData();
 498   unsigned NewData = (OldData & ~(CodeModelMask << CodeModelShift)) |
 499                      (CodeModelData << CodeModelShift);
 500   setGlobalValueSubClassData(NewData);
 501   assert(getCodeModel() == CM && "Code model representation error!");
 502 }
 503
 504 //===----------------------------------------------------------------------===//
 505 // GlobalAlias Implementation
 506 //===----------------------------------------------------------------------===//
 507
 508 GlobalAlias::GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Link,
 509                          const Twine &Name, Constant *Aliasee,
 510                          Module *ParentModule)
 511     : GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name,
 512                   AddressSpace) {
 513   setAliasee(Aliasee);
 514   if (ParentModule)
 515     ParentModule->insertAlias(this);
 516 }
 517
 518 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
 519                                  LinkageTypes Link, const Twine &Name,
 520                                  Constant *Aliasee, Module *ParentModule) {
 521   return new GlobalAlias(Ty, AddressSpace, Link, Name, Aliasee, ParentModule);
 522 }
 523
 524 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
 525                                  LinkageTypes Linkage, const Twine &Name,
 526                                  Module *Parent) {
 527   return create(Ty, AddressSpace, Linkage, Name, nullptr, Parent);
 528 }
 529
 530 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
 531                                  LinkageTypes Linkage, const Twine &Name,
 532                                  GlobalValue *Aliasee) {
 533   return create(Ty, AddressSpace, Linkage, Name, Aliasee, Aliasee->getParent());
 534 }
 535
 536 GlobalAlias *GlobalAlias::create(LinkageTypes Link, const Twine &Name,
 537                                  GlobalValue *Aliasee) {
 538   return create(Aliasee->getValueType(), Aliasee->getAddressSpace(), Link, Name,
 539                 Aliasee);
 540 }
 541
 542 GlobalAlias *GlobalAlias::create(const Twine &Name, GlobalValue *Aliasee) {
 543   return create(Aliasee->getLinkage(), Name, Aliasee);
 544 }
 545
 546 void GlobalAlias::removeFromParent() { getParent()->removeAlias(this); }
 547
 548 void GlobalAlias::eraseFromParent() { getParent()->eraseAlias(this); }
 549
 550 void GlobalAlias::setAliasee(Constant *Aliasee) {
 551   assert((!Aliasee || Aliasee->getType() == getType()) &&
 552          "Alias and aliasee types should match!");
 553   Op<0>().set(Aliasee);
 554 }
 555
 556 const GlobalObject *GlobalAlias::getAliaseeObject() const {
 557   DenseSet<const GlobalAlias *> Aliases;
 558   return findBaseObject(getOperand(0), Aliases, [](const GlobalValue &) {});
 559 }
 560
 561 //===----------------------------------------------------------------------===//
 562 // GlobalIFunc Implementation
 563 //===----------------------------------------------------------------------===//
 564
 565 GlobalIFunc::GlobalIFunc(Type *Ty, unsigned AddressSpace, LinkageTypes Link,
 566                          const Twine &Name, Constant *Resolver,
 567                          Module *ParentModule)
 568     : GlobalObject(Ty, Value::GlobalIFuncVal, &Op<0>(), 1, Link, Name,
 569                    AddressSpace) {
 570   setResolver(Resolver);
 571   if (ParentModule)
 572     ParentModule->insertIFunc(this);
 573 }
 574
 575 GlobalIFunc *GlobalIFunc::create(Type *Ty, unsigned AddressSpace,
 576                                  LinkageTypes Link, const Twine &Name,
 577                                  Constant *Resolver, Module *ParentModule) {
 578   return new GlobalIFunc(Ty, AddressSpace, Link, Name, Resolver, ParentModule);
 579 }
 580
 581 void GlobalIFunc::removeFromParent() { getParent()->removeIFunc(this); }
 582
 583 void GlobalIFunc::eraseFromParent() { getParent()->eraseIFunc(this); }
 584
 585 const Function *GlobalIFunc::getResolverFunction() const {
 586   return dyn_cast<Function>(getResolver()->stripPointerCastsAndAliases());
 587 }
 588
 589 void GlobalIFunc::applyAlongResolverPath(
 590     function_ref<void(const GlobalValue &)> Op) const {
 591   DenseSet<const GlobalAlias *> Aliases;
 592   findBaseObject(getResolver(), Aliases, Op);
 593 }