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
 148   // Value names may be prefixed with a binary '1' to indicate
 149   // that the backend should not modify the symbols due to any platform
 150   // naming convention. Do not include that '1' in the PGO profile name.
 151   if (Name[0] == '\1')
 152     Name = Name.substr(1);
 153
 154   std::string NewName = std::string(Name);
 155   if (llvm::GlobalValue::isLocalLinkage(Linkage)) {
 156     // For local symbols, prepend the main file name to distinguish them.
 157     // Do not include the full path in the file name since there's no guarantee
 158     // that it will stay the same, e.g., if the files are checked out from
 159     // version control in different locations.
 160     if (FileName.empty())
 161       NewName = NewName.insert(0, "<unknown>:");
 162     else
 163       NewName = NewName.insert(0, FileName.str() + ":");
 164   }
 165   return NewName;
 166 }
 167
 168 std::string GlobalValue::getGlobalIdentifier() const {
 169   return getGlobalIdentifier(getName(), getLinkage(),
 170                              getParent()->getSourceFileName());
 171 }
 172
 173 StringRef GlobalValue::getSection() const {
 174   if (auto *GA = dyn_cast<GlobalAlias>(this)) {
 175     // In general we cannot compute this at the IR level, but we try.
 176     if (const GlobalObject *GO = GA->getAliaseeObject())
 177       return GO->getSection();
 178     return "";
 179   }
 180   return cast<GlobalObject>(this)->getSection();
 181 }
 182
 183 const Comdat *GlobalValue::getComdat() const {
 184   if (auto *GA = dyn_cast<GlobalAlias>(this)) {
 185     // In general we cannot compute this at the IR level, but we try.
 186     if (const GlobalObject *GO = GA->getAliaseeObject())
 187       return const_cast<GlobalObject *>(GO)->getComdat();
 188     return nullptr;
 189   }
 190   // ifunc and its resolver are separate things so don't use resolver comdat.
 191   if (isa<GlobalIFunc>(this))
 192     return nullptr;
 193   return cast<GlobalObject>(this)->getComdat();
 194 }
 195
 196 void GlobalObject::setComdat(Comdat *C) {
 197   if (ObjComdat)
 198     ObjComdat->removeUser(this);
 199   ObjComdat = C;
 200   if (C)
 201     C->addUser(this);
 202 }
 203
 204 StringRef GlobalValue::getPartition() const {
 205   if (!hasPartition())
 206     return "";
 207   return getContext().pImpl->GlobalValuePartitions[this];
 208 }
 209
 210 void GlobalValue::setPartition(StringRef S) {
 211   // Do nothing if we're clearing the partition and it is already empty.
 212   if (!hasPartition() && S.empty())
 213     return;
 214
 215   // Get or create a stable partition name string and put it in the table in the
 216   // context.
 217   if (!S.empty())
 218     S = getContext().pImpl->Saver.save(S);
 219   getContext().pImpl->GlobalValuePartitions[this] = S;
 220
 221   // Update the HasPartition field. Setting the partition to the empty string
 222   // means this global no longer has a partition.
 223   HasPartition = !S.empty();
 224 }
 225
 226 using SanitizerMetadata = GlobalValue::SanitizerMetadata;
 227 const SanitizerMetadata &GlobalValue::getSanitizerMetadata() const {
 228   assert(hasSanitizerMetadata());
 229   assert(getContext().pImpl->GlobalValueSanitizerMetadata.count(this));
 230   return getContext().pImpl->GlobalValueSanitizerMetadata[this];
 231 }
 232
 233 void GlobalValue::setSanitizerMetadata(SanitizerMetadata Meta) {
 234   getContext().pImpl->GlobalValueSanitizerMetadata[this] = Meta;
 235   HasSanitizerMetadata = true;
 236 }
 237
 238 void GlobalValue::removeSanitizerMetadata() {
 239   DenseMap<const GlobalValue *, SanitizerMetadata> &MetadataMap =
 240       getContext().pImpl->GlobalValueSanitizerMetadata;
 241   MetadataMap.erase(this);
 242   HasSanitizerMetadata = false;
 243 }
 244
 245 StringRef GlobalObject::getSectionImpl() const {
 246   assert(hasSection());
 247   return getContext().pImpl->GlobalObjectSections[this];
 248 }
 249
 250 void GlobalObject::setSection(StringRef S) {
 251   // Do nothing if we're clearing the section and it is already empty.
 252   if (!hasSection() && S.empty())
 253     return;
 254
 255   // Get or create a stable section name string and put it in the table in the
 256   // context.
 257   if (!S.empty())
 258     S = getContext().pImpl->Saver.save(S);
 259   getContext().pImpl->GlobalObjectSections[this] = S;
 260
 261   // Update the HasSectionHashEntryBit. Setting the section to the empty string
 262   // means this global no longer has a section.
 263   setGlobalObjectFlag(HasSectionHashEntryBit, !S.empty());
 264 }
 265
 266 bool GlobalValue::isNobuiltinFnDef() const {
 267   const Function *F = dyn_cast<Function>(this);
 268   if (!F || F->empty())
 269     return false;
 270   return F->hasFnAttribute(Attribute::NoBuiltin);
 271 }
 272
 273 bool GlobalValue::isDeclaration() const {
 274   // Globals are definitions if they have an initializer.
 275   if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(this))
 276     return GV->getNumOperands() == 0;
 277
 278   // Functions are definitions if they have a body.
 279   if (const Function *F = dyn_cast<Function>(this))
 280     return F->empty() && !F->isMaterializable();
 281
 282   // Aliases and ifuncs are always definitions.
 283   assert(isa<GlobalAlias>(this) || isa<GlobalIFunc>(this));
 284   return false;
 285 }
 286
 287 bool GlobalObject::canIncreaseAlignment() const {
 288   // Firstly, can only increase the alignment of a global if it
 289   // is a strong definition.
 290   if (!isStrongDefinitionForLinker())
 291     return false;
 292
 293   // It also has to either not have a section defined, or, not have
 294   // alignment specified. (If it is assigned a section, the global
 295   // could be densely packed with other objects in the section, and
 296   // increasing the alignment could cause padding issues.)
 297   if (hasSection() && getAlign())
 298     return false;
 299
 300   // On ELF platforms, we're further restricted in that we can't
 301   // increase the alignment of any variable which might be emitted
 302   // into a shared library, and which is exported. If the main
 303   // executable accesses a variable found in a shared-lib, the main
 304   // exe actually allocates memory for and exports the symbol ITSELF,
 305   // overriding the symbol found in the library. That is, at link
 306   // time, the observed alignment of the variable is copied into the
 307   // executable binary. (A COPY relocation is also generated, to copy
 308   // the initial data from the shadowed variable in the shared-lib
 309   // into the location in the main binary, before running code.)
 310   //
 311   // And thus, even though you might think you are defining the
 312   // global, and allocating the memory for the global in your object
 313   // file, and thus should be able to set the alignment arbitrarily,
 314   // that's not actually true. Doing so can cause an ABI breakage; an
 315   // executable might have already been built with the previous
 316   // alignment of the variable, and then assuming an increased
 317   // alignment will be incorrect.
 318
 319   // Conservatively assume ELF if there's no parent pointer.
 320   bool isELF =
 321       (!Parent || Triple(Parent->getTargetTriple()).isOSBinFormatELF());
 322   if (isELF && !isDSOLocal())
 323     return false;
 324
 325   return true;
 326 }
 327
 328 template <typename Operation>
 329 static const GlobalObject *
 330 findBaseObject(const Constant *C, DenseSet<const GlobalAlias *> &Aliases,
 331                const Operation &Op) {
 332   if (auto *GO = dyn_cast<GlobalObject>(C)) {
 333     Op(*GO);
 334     return GO;
 335   }
 336   if (auto *GA = dyn_cast<GlobalAlias>(C)) {
 337     Op(*GA);
 338     if (Aliases.insert(GA).second)
 339       return findBaseObject(GA->getOperand(0), Aliases, Op);
 340   }
 341   if (auto *CE = dyn_cast<ConstantExpr>(C)) {
 342     switch (CE->getOpcode()) {
 343     case Instruction::Add: {
 344       auto *LHS = findBaseObject(CE->getOperand(0), Aliases, Op);
 345       auto *RHS = findBaseObject(CE->getOperand(1), Aliases, Op);
 346       if (LHS && RHS)
 347         return nullptr;
 348       return LHS ? LHS : RHS;
 349     }
 350     case Instruction::Sub: {
 351       if (findBaseObject(CE->getOperand(1), Aliases, Op))
 352         return nullptr;
 353       return findBaseObject(CE->getOperand(0), Aliases, Op);
 354     }
 355     case Instruction::IntToPtr:
 356     case Instruction::PtrToInt:
 357     case Instruction::BitCast:
 358     case Instruction::GetElementPtr:
 359       return findBaseObject(CE->getOperand(0), Aliases, Op);
 360     default:
 361       break;
 362     }
 363   }
 364   return nullptr;
 365 }
 366
 367 const GlobalObject *GlobalValue::getAliaseeObject() const {
 368   DenseSet<const GlobalAlias *> Aliases;
 369   return findBaseObject(this, Aliases, [](const GlobalValue &) {});
 370 }
 371
 372 bool GlobalValue::isAbsoluteSymbolRef() const {
 373   auto *GO = dyn_cast<GlobalObject>(this);
 374   if (!GO)
 375     return false;
 376
 377   return GO->getMetadata(LLVMContext::MD_absolute_symbol);
 378 }
 379
 380 std::optional<ConstantRange> GlobalValue::getAbsoluteSymbolRange() const {
 381   auto *GO = dyn_cast<GlobalObject>(this);
 382   if (!GO)
 383     return std::nullopt;
 384
 385   MDNode *MD = GO->getMetadata(LLVMContext::MD_absolute_symbol);
 386   if (!MD)
 387     return std::nullopt;
 388
 389   return getConstantRangeFromMetadata(*MD);
 390 }
 391
 392 bool GlobalValue::canBeOmittedFromSymbolTable() const {
 393   if (!hasLinkOnceODRLinkage())
 394     return false;
 395
 396   // We assume that anyone who sets global unnamed_addr on a non-constant
 397   // knows what they're doing.
 398   if (hasGlobalUnnamedAddr())
 399     return true;
 400
 401   // If it is a non constant variable, it needs to be uniqued across shared
 402   // objects.
 403   if (auto *Var = dyn_cast<GlobalVariable>(this))
 404     if (!Var->isConstant())
 405       return false;
 406
 407   return hasAtLeastLocalUnnamedAddr();
 408 }
 409
 410 //===----------------------------------------------------------------------===//
 411 // GlobalVariable Implementation
 412 //===----------------------------------------------------------------------===//
 413
 414 GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
 415                                Constant *InitVal, const Twine &Name,
 416                                ThreadLocalMode TLMode, unsigned AddressSpace,
 417                                bool isExternallyInitialized)
 418     : GlobalObject(Ty, Value::GlobalVariableVal,
 419                    OperandTraits<GlobalVariable>::op_begin(this),
 420                    InitVal != nullptr, Link, Name, AddressSpace),
 421       isConstantGlobal(constant),
 422       isExternallyInitializedConstant(isExternallyInitialized) {
 423   assert(!Ty->isFunctionTy() && PointerType::isValidElementType(Ty) &&
 424          "invalid type for global variable");
 425   setThreadLocalMode(TLMode);
 426   if (InitVal) {
 427     assert(InitVal->getType() == Ty &&
 428            "Initializer should be the same type as the GlobalVariable!");
 429     Op<0>() = InitVal;
 430   }
 431 }
 432
 433 GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant,
 434                                LinkageTypes Link, Constant *InitVal,
 435                                const Twine &Name, GlobalVariable *Before,
 436                                ThreadLocalMode TLMode,
 437                                std::optional<unsigned> AddressSpace,
 438                                bool isExternallyInitialized)
 439     : GlobalVariable(Ty, constant, Link, InitVal, Name, TLMode,
 440                      AddressSpace
 441                          ? *AddressSpace
 442                          : M.getDataLayout().getDefaultGlobalsAddressSpace(),
 443                      isExternallyInitialized) {
 444   if (Before)
 445     Before->getParent()->insertGlobalVariable(Before->getIterator(), this);
 446   else
 447     M.insertGlobalVariable(this);
 448 }
 449
 450 void GlobalVariable::removeFromParent() {
 451   getParent()->removeGlobalVariable(this);
 452 }
 453
 454 void GlobalVariable::eraseFromParent() {
 455   getParent()->eraseGlobalVariable(this);
 456 }
 457
 458 void GlobalVariable::setInitializer(Constant *InitVal) {
 459   if (!InitVal) {
 460     if (hasInitializer()) {
 461       // Note, the num operands is used to compute the offset of the operand, so
 462       // the order here matters.  Clearing the operand then clearing the num
 463       // operands ensures we have the correct offset to the operand.
 464       Op<0>().set(nullptr);
 465       setGlobalVariableNumOperands(0);
 466     }
 467   } else {
 468     assert(InitVal->getType() == getValueType() &&
 469            "Initializer type must match GlobalVariable type");
 470     // Note, the num operands is used to compute the offset of the operand, so
 471     // the order here matters.  We need to set num operands to 1 first so that
 472     // we get the correct offset to the first operand when we set it.
 473     if (!hasInitializer())
 474       setGlobalVariableNumOperands(1);
 475     Op<0>().set(InitVal);
 476   }
 477 }
 478
 479 /// Copy all additional attributes (those not needed to create a GlobalVariable)
 480 /// from the GlobalVariable Src to this one.
 481 void GlobalVariable::copyAttributesFrom(const GlobalVariable *Src) {
 482   GlobalObject::copyAttributesFrom(Src);
 483   setExternallyInitialized(Src->isExternallyInitialized());
 484   setAttributes(Src->getAttributes());
 485 }
 486
 487 void GlobalVariable::dropAllReferences() {
 488   User::dropAllReferences();
 489   clearMetadata();
 490 }
 491
 492 //===----------------------------------------------------------------------===//
 493 // GlobalAlias Implementation
 494 //===----------------------------------------------------------------------===//
 495
 496 GlobalAlias::GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Link,
 497                          const Twine &Name, Constant *Aliasee,
 498                          Module *ParentModule)
 499     : GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name,
 500                   AddressSpace) {
 501   setAliasee(Aliasee);
 502   if (ParentModule)
 503     ParentModule->insertAlias(this);
 504 }
 505
 506 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
 507                                  LinkageTypes Link, const Twine &Name,
 508                                  Constant *Aliasee, Module *ParentModule) {
 509   return new GlobalAlias(Ty, AddressSpace, Link, Name, Aliasee, ParentModule);
 510 }
 511
 512 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
 513                                  LinkageTypes Linkage, const Twine &Name,
 514                                  Module *Parent) {
 515   return create(Ty, AddressSpace, Linkage, Name, nullptr, Parent);
 516 }
 517
 518 GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
 519                                  LinkageTypes Linkage, const Twine &Name,
 520                                  GlobalValue *Aliasee) {
 521   return create(Ty, AddressSpace, Linkage, Name, Aliasee, Aliasee->getParent());
 522 }
 523
 524 GlobalAlias *GlobalAlias::create(LinkageTypes Link, const Twine &Name,
 525                                  GlobalValue *Aliasee) {
 526   return create(Aliasee->getValueType(), Aliasee->getAddressSpace(), Link, Name,
 527                 Aliasee);
 528 }
 529
 530 GlobalAlias *GlobalAlias::create(const Twine &Name, GlobalValue *Aliasee) {
 531   return create(Aliasee->getLinkage(), Name, Aliasee);
 532 }
 533
 534 void GlobalAlias::removeFromParent() { getParent()->removeAlias(this); }
 535
 536 void GlobalAlias::eraseFromParent() { getParent()->eraseAlias(this); }
 537
 538 void GlobalAlias::setAliasee(Constant *Aliasee) {
 539   assert((!Aliasee || Aliasee->getType() == getType()) &&
 540          "Alias and aliasee types should match!");
 541   Op<0>().set(Aliasee);
 542 }
 543
 544 const GlobalObject *GlobalAlias::getAliaseeObject() const {
 545   DenseSet<const GlobalAlias *> Aliases;
 546   return findBaseObject(getOperand(0), Aliases, [](const GlobalValue &) {});
 547 }
 548
 549 //===----------------------------------------------------------------------===//
 550 // GlobalIFunc Implementation
 551 //===----------------------------------------------------------------------===//
 552
 553 GlobalIFunc::GlobalIFunc(Type *Ty, unsigned AddressSpace, LinkageTypes Link,
 554                          const Twine &Name, Constant *Resolver,
 555                          Module *ParentModule)
 556     : GlobalObject(Ty, Value::GlobalIFuncVal, &Op<0>(), 1, Link, Name,
 557                    AddressSpace) {
 558   setResolver(Resolver);
 559   if (ParentModule)
 560     ParentModule->insertIFunc(this);
 561 }
 562
 563 GlobalIFunc *GlobalIFunc::create(Type *Ty, unsigned AddressSpace,
 564                                  LinkageTypes Link, const Twine &Name,
 565                                  Constant *Resolver, Module *ParentModule) {
 566   return new GlobalIFunc(Ty, AddressSpace, Link, Name, Resolver, ParentModule);
 567 }
 568
 569 void GlobalIFunc::removeFromParent() { getParent()->removeIFunc(this); }
 570
 571 void GlobalIFunc::eraseFromParent() { getParent()->eraseIFunc(this); }
 572
 573 const Function *GlobalIFunc::getResolverFunction() const {
 574   return dyn_cast<Function>(getResolver()->stripPointerCastsAndAliases());
 575 }
 576
 577 void GlobalIFunc::applyAlongResolverPath(
 578     function_ref<void(const GlobalValue &)> Op) const {
 579   DenseSet<const GlobalAlias *> Aliases;
 580   findBaseObject(getResolver(), Aliases, Op);
 581 }