Remove LLVM 8.0.1 files.

1 files changed, 0 insertions, 1493 deletions

diff --git a/gnu/llvm/lib/Linker/IRMover.cpp b/gnu/llvm/lib/Linker/IRMover.cpp
deleted file mode 100644
index afbc57abfcc..00000000000
--- a/gnu/llvm/lib/Linker/IRMover.cpp
+++ /dev/null
@@ -1,1493 +0,0 @@
-//===- lib/Linker/IRMover.cpp ---------------------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Linker/IRMover.h"
-#include "LinkDiagnosticInfo.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/SmallString.h"
-#include "llvm/ADT/Triple.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DebugInfo.h"
-#include "llvm/IR/DiagnosticPrinter.h"
-#include "llvm/IR/GVMaterializer.h"
-#include "llvm/IR/Intrinsics.h"
-#include "llvm/IR/TypeFinder.h"
-#include "llvm/Support/Error.h"
-#include "llvm/Transforms/Utils/Cloning.h"
-#include <utility>
-using namespace llvm;
-
-//===----------------------------------------------------------------------===//
-// TypeMap implementation.
-//===----------------------------------------------------------------------===//
-
-namespace {
-class TypeMapTy : public ValueMapTypeRemapper {
-  /// This is a mapping from a source type to a destination type to use.
-  DenseMap<Type *, Type *> MappedTypes;
-
-  /// When checking to see if two subgraphs are isomorphic, we speculatively
-  /// add types to MappedTypes, but keep track of them here in case we need to
-  /// roll back.
-  SmallVector<Type *, 16> SpeculativeTypes;
-
-  SmallVector<StructType *, 16> SpeculativeDstOpaqueTypes;
-
-  /// This is a list of non-opaque structs in the source module that are mapped
-  /// to an opaque struct in the destination module.
-  SmallVector<StructType *, 16> SrcDefinitionsToResolve;
-
-  /// This is the set of opaque types in the destination modules who are
-  /// getting a body from the source module.
-  SmallPtrSet<StructType *, 16> DstResolvedOpaqueTypes;
-
-public:
-  TypeMapTy(IRMover::IdentifiedStructTypeSet &DstStructTypesSet)
-      : DstStructTypesSet(DstStructTypesSet) {}
-
-  IRMover::IdentifiedStructTypeSet &DstStructTypesSet;
-  /// Indicate that the specified type in the destination module is conceptually
-  /// equivalent to the specified type in the source module.
-  void addTypeMapping(Type *DstTy, Type *SrcTy);
-
-  /// Produce a body for an opaque type in the dest module from a type
-  /// definition in the source module.
-  void linkDefinedTypeBodies();
-
-  /// Return the mapped type to use for the specified input type from the
-  /// source module.
-  Type *get(Type *SrcTy);
-  Type *get(Type *SrcTy, SmallPtrSet<StructType *, 8> &Visited);
-
-  void finishType(StructType *DTy, StructType *STy, ArrayRef<Type *> ETypes);
-
-  FunctionType *get(FunctionType *T) {
-    return cast<FunctionType>(get((Type *)T));
-  }
-
-private:
-  Type *remapType(Type *SrcTy) override { return get(SrcTy); }
-
-  bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
-};
-}
-
-void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
-  assert(SpeculativeTypes.empty());
-  assert(SpeculativeDstOpaqueTypes.empty());
-
-  // Check to see if these types are recursively isomorphic and establish a
-  // mapping between them if so.
-  if (!areTypesIsomorphic(DstTy, SrcTy)) {
-    // Oops, they aren't isomorphic.  Just discard this request by rolling out
-    // any speculative mappings we've established.
-    for (Type *Ty : SpeculativeTypes)
-      MappedTypes.erase(Ty);
-
-    SrcDefinitionsToResolve.resize(SrcDefinitionsToResolve.size() -
-                                   SpeculativeDstOpaqueTypes.size());
-    for (StructType *Ty : SpeculativeDstOpaqueTypes)
-      DstResolvedOpaqueTypes.erase(Ty);
-  } else {
-    // SrcTy and DstTy are recursively ismorphic. We clear names of SrcTy
-    // and all its descendants to lower amount of renaming in LLVM context
-    // Renaming occurs because we load all source modules to the same context
-    // and declaration with existing name gets renamed (i.e Foo -> Foo.42).
-    // As a result we may get several different types in the destination
-    // module, which are in fact the same.
-    for (Type *Ty : SpeculativeTypes)
-      if (auto *STy = dyn_cast<StructType>(Ty))
-        if (STy->hasName())
-          STy->setName("");
-  }
-  SpeculativeTypes.clear();
-  SpeculativeDstOpaqueTypes.clear();
-}
-
-/// Recursively walk this pair of types, returning true if they are isomorphic,
-/// false if they are not.
-bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
-  // Two types with differing kinds are clearly not isomorphic.
-  if (DstTy->getTypeID() != SrcTy->getTypeID())
-    return false;
-
-  // If we have an entry in the MappedTypes table, then we have our answer.
-  Type *&Entry = MappedTypes[SrcTy];
-  if (Entry)
-    return Entry == DstTy;
-
-  // Two identical types are clearly isomorphic.  Remember this
-  // non-speculatively.
-  if (DstTy == SrcTy) {
-    Entry = DstTy;
-    return true;
-  }
-
-  // Okay, we have two types with identical kinds that we haven't seen before.
-
-  // If this is an opaque struct type, special case it.
-  if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
-    // Mapping an opaque type to any struct, just keep the dest struct.
-    if (SSTy->isOpaque()) {
-      Entry = DstTy;
-      SpeculativeTypes.push_back(SrcTy);
-      return true;
-    }
-
-    // Mapping a non-opaque source type to an opaque dest.  If this is the first
-    // type that we're mapping onto this destination type then we succeed.  Keep
-    // the dest, but fill it in later. If this is the second (different) type
-    // that we're trying to map onto the same opaque type then we fail.
-    if (cast<StructType>(DstTy)->isOpaque()) {
-      // We can only map one source type onto the opaque destination type.
-      if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)).second)
-        return false;
-      SrcDefinitionsToResolve.push_back(SSTy);
-      SpeculativeTypes.push_back(SrcTy);
-      SpeculativeDstOpaqueTypes.push_back(cast<StructType>(DstTy));
-      Entry = DstTy;
-      return true;
-    }
-  }
-
-  // If the number of subtypes disagree between the two types, then we fail.
-  if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
-    return false;
-
-  // Fail if any of the extra properties (e.g. array size) of the type disagree.
-  if (isa<IntegerType>(DstTy))
-    return false; // bitwidth disagrees.
-  if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
-    if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
-      return false;
-  } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
-    if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
-      return false;
-  } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
-    StructType *SSTy = cast<StructType>(SrcTy);
-    if (DSTy->isLiteral() != SSTy->isLiteral() ||
-        DSTy->isPacked() != SSTy->isPacked())
-      return false;
-  } else if (auto *DSeqTy = dyn_cast<SequentialType>(DstTy)) {
-    if (DSeqTy->getNumElements() !=
-        cast<SequentialType>(SrcTy)->getNumElements())
-      return false;
-  }
-
-  // Otherwise, we speculate that these two types will line up and recursively
-  // check the subelements.
-  Entry = DstTy;
-  SpeculativeTypes.push_back(SrcTy);
-
-  for (unsigned I = 0, E = SrcTy->getNumContainedTypes(); I != E; ++I)
-    if (!areTypesIsomorphic(DstTy->getContainedType(I),
-                            SrcTy->getContainedType(I)))
-      return false;
-
-  // If everything seems to have lined up, then everything is great.
-  return true;
-}
-
-void TypeMapTy::linkDefinedTypeBodies() {
-  SmallVector<Type *, 16> Elements;
-  for (StructType *SrcSTy : SrcDefinitionsToResolve) {
-    StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
-    assert(DstSTy->isOpaque());
-
-    // Map the body of the source type over to a new body for the dest type.
-    Elements.resize(SrcSTy->getNumElements());
-    for (unsigned I = 0, E = Elements.size(); I != E; ++I)
-      Elements[I] = get(SrcSTy->getElementType(I));
-
-    DstSTy->setBody(Elements, SrcSTy->isPacked());
-    DstStructTypesSet.switchToNonOpaque(DstSTy);
-  }
-  SrcDefinitionsToResolve.clear();
-  DstResolvedOpaqueTypes.clear();
-}
-
-void TypeMapTy::finishType(StructType *DTy, StructType *STy,
-                           ArrayRef<Type *> ETypes) {
-  DTy->setBody(ETypes, STy->isPacked());
-
-  // Steal STy's name.
-  if (STy->hasName()) {
-    SmallString<16> TmpName = STy->getName();
-    STy->setName("");
-    DTy->setName(TmpName);
-  }
-
-  DstStructTypesSet.addNonOpaque(DTy);
-}
-
-Type *TypeMapTy::get(Type *Ty) {
-  SmallPtrSet<StructType *, 8> Visited;
-  return get(Ty, Visited);
-}
-
-Type *TypeMapTy::get(Type *Ty, SmallPtrSet<StructType *, 8> &Visited) {
-  // If we already have an entry for this type, return it.
-  Type **Entry = &MappedTypes[Ty];
-  if (*Entry)
-    return *Entry;
-
-  // These are types that LLVM itself will unique.
-  bool IsUniqued = !isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral();
-
-  if (!IsUniqued) {
-    StructType *STy = cast<StructType>(Ty);
-    // This is actually a type from the destination module, this can be reached
-    // when this type is loaded in another module, added to DstStructTypesSet,
-    // and then we reach the same type in another module where it has not been
-    // added to MappedTypes. (PR37684)
-    if (STy->getContext().isODRUniquingDebugTypes() && !STy->isOpaque() &&
-        DstStructTypesSet.hasType(STy))
-      return *Entry = STy;
-
-#ifndef NDEBUG
-    for (auto &Pair : MappedTypes) {
-      assert(!(Pair.first != Ty && Pair.second == Ty) &&
-             "mapping to a source type");
-    }
-#endif
-
-    if (!Visited.insert(STy).second) {
-      StructType *DTy = StructType::create(Ty->getContext());
-      return *Entry = DTy;
-    }
-  }
-
-  // If this is not a recursive type, then just map all of the elements and
-  // then rebuild the type from inside out.
-  SmallVector<Type *, 4> ElementTypes;
-
-  // If there are no element types to map, then the type is itself.  This is
-  // true for the anonymous {} struct, things like 'float', integers, etc.
-  if (Ty->getNumContainedTypes() == 0 && IsUniqued)
-    return *Entry = Ty;
-
-  // Remap all of the elements, keeping track of whether any of them change.
-  bool AnyChange = false;
-  ElementTypes.resize(Ty->getNumContainedTypes());
-  for (unsigned I = 0, E = Ty->getNumContainedTypes(); I != E; ++I) {
-    ElementTypes[I] = get(Ty->getContainedType(I), Visited);
-    AnyChange |= ElementTypes[I] != Ty->getContainedType(I);
-  }
-
-  // If we found our type while recursively processing stuff, just use it.
-  Entry = &MappedTypes[Ty];
-  if (*Entry) {
-    if (auto *DTy = dyn_cast<StructType>(*Entry)) {
-      if (DTy->isOpaque()) {
-        auto *STy = cast<StructType>(Ty);
-        finishType(DTy, STy, ElementTypes);
-      }
-    }
-    return *Entry;
-  }
-
-  // If all of the element types mapped directly over and the type is not
-  // a named struct, then the type is usable as-is.
-  if (!AnyChange && IsUniqued)
-    return *Entry = Ty;
-
-  // Otherwise, rebuild a modified type.
-  switch (Ty->getTypeID()) {
-  default:
-    llvm_unreachable("unknown derived type to remap");
-  case Type::ArrayTyID:
-    return *Entry = ArrayType::get(ElementTypes[0],
-                                   cast<ArrayType>(Ty)->getNumElements());
-  case Type::VectorTyID:
-    return *Entry = VectorType::get(ElementTypes[0],
-                                    cast<VectorType>(Ty)->getNumElements());
-  case Type::PointerTyID:
-    return *Entry = PointerType::get(ElementTypes[0],
-                                     cast<PointerType>(Ty)->getAddressSpace());
-  case Type::FunctionTyID:
-    return *Entry = FunctionType::get(ElementTypes[0],
-                                      makeArrayRef(ElementTypes).slice(1),
-                                      cast<FunctionType>(Ty)->isVarArg());
-  case Type::StructTyID: {
-    auto *STy = cast<StructType>(Ty);
-    bool IsPacked = STy->isPacked();
-    if (IsUniqued)
-      return *Entry = StructType::get(Ty->getContext(), ElementTypes, IsPacked);
-
-    // If the type is opaque, we can just use it directly.
-    if (STy->isOpaque()) {
-      DstStructTypesSet.addOpaque(STy);
-      return *Entry = Ty;
-    }
-
-    if (StructType *OldT =
-            DstStructTypesSet.findNonOpaque(ElementTypes, IsPacked)) {
-      STy->setName("");
-      return *Entry = OldT;
-    }
-
-    if (!AnyChange) {
-      DstStructTypesSet.addNonOpaque(STy);
-      return *Entry = Ty;
-    }
-
-    StructType *DTy = StructType::create(Ty->getContext());
-    finishType(DTy, STy, ElementTypes);
-    return *Entry = DTy;
-  }
-  }
-}
-
-LinkDiagnosticInfo::LinkDiagnosticInfo(DiagnosticSeverity Severity,
-                                       const Twine &Msg)
-    : DiagnosticInfo(DK_Linker, Severity), Msg(Msg) {}
-void LinkDiagnosticInfo::print(DiagnosticPrinter &DP) const { DP << Msg; }
-
-//===----------------------------------------------------------------------===//
-// IRLinker implementation.
-//===----------------------------------------------------------------------===//
-
-namespace {
-class IRLinker;
-
-/// Creates prototypes for functions that are lazily linked on the fly. This
-/// speeds up linking for modules with many/ lazily linked functions of which
-/// few get used.
-class GlobalValueMaterializer final : public ValueMaterializer {
-  IRLinker &TheIRLinker;
-
-public:
-  GlobalValueMaterializer(IRLinker &TheIRLinker) : TheIRLinker(TheIRLinker) {}
-  Value *materialize(Value *V) override;
-};
-
-class LocalValueMaterializer final : public ValueMaterializer {
-  IRLinker &TheIRLinker;
-
-public:
-  LocalValueMaterializer(IRLinker &TheIRLinker) : TheIRLinker(TheIRLinker) {}
-  Value *materialize(Value *V) override;
-};
-
-/// Type of the Metadata map in \a ValueToValueMapTy.
-typedef DenseMap<const Metadata *, TrackingMDRef> MDMapT;
-
-/// This is responsible for keeping track of the state used for moving data
-/// from SrcM to DstM.
-class IRLinker {
-  Module &DstM;
-  std::unique_ptr<Module> SrcM;
-
-  /// See IRMover::move().
-  std::function<void(GlobalValue &, IRMover::ValueAdder)> AddLazyFor;
-
-  TypeMapTy TypeMap;
-  GlobalValueMaterializer GValMaterializer;
-  LocalValueMaterializer LValMaterializer;
-
-  /// A metadata map that's shared between IRLinker instances.
-  MDMapT &SharedMDs;
-
-  /// Mapping of values from what they used to be in Src, to what they are now
-  /// in DstM.  ValueToValueMapTy is a ValueMap, which involves some overhead
-  /// due to the use of Value handles which the Linker doesn't actually need,
-  /// but this allows us to reuse the ValueMapper code.
-  ValueToValueMapTy ValueMap;
-  ValueToValueMapTy AliasValueMap;
-
-  DenseSet<GlobalValue *> ValuesToLink;
-  std::vector<GlobalValue *> Worklist;
-
-  void maybeAdd(GlobalValue *GV) {
-    if (ValuesToLink.insert(GV).second)
-      Worklist.push_back(GV);
-  }
-
-  /// Whether we are importing globals for ThinLTO, as opposed to linking the
-  /// source module. If this flag is set, it means that we can rely on some
-  /// other object file to define any non-GlobalValue entities defined by the
-  /// source module. This currently causes us to not link retained types in
-  /// debug info metadata and module inline asm.
-  bool IsPerformingImport;
-
-  /// Set to true when all global value body linking is complete (including
-  /// lazy linking). Used to prevent metadata linking from creating new
-  /// references.
-  bool DoneLinkingBodies = false;
-
-  /// The Error encountered during materialization. We use an Optional here to
-  /// avoid needing to manage an unconsumed success value.
-  Optional<Error> FoundError;
-  void setError(Error E) {
-    if (E)
-      FoundError = std::move(E);
-  }
-
-  /// Most of the errors produced by this module are inconvertible StringErrors.
-  /// This convenience function lets us return one of those more easily.
-  Error stringErr(const Twine &T) {
-    return make_error<StringError>(T, inconvertibleErrorCode());
-  }
-
-  /// Entry point for mapping values and alternate context for mapping aliases.
-  ValueMapper Mapper;
-  unsigned AliasMCID;
-
-  /// Handles cloning of a global values from the source module into
-  /// the destination module, including setting the attributes and visibility.
-  GlobalValue *copyGlobalValueProto(const GlobalValue *SGV, bool ForDefinition);
-
-  void emitWarning(const Twine &Message) {
-    SrcM->getContext().diagnose(LinkDiagnosticInfo(DS_Warning, Message));
-  }
-
-  /// Given a global in the source module, return the global in the
-  /// destination module that is being linked to, if any.
-  GlobalValue *getLinkedToGlobal(const GlobalValue *SrcGV) {
-    // If the source has no name it can't link.  If it has local linkage,
-    // there is no name match-up going on.
-    if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
-      return nullptr;
-
-    // Otherwise see if we have a match in the destination module's symtab.
-    GlobalValue *DGV = DstM.getNamedValue(SrcGV->getName());
-    if (!DGV)
-      return nullptr;
-
-    // If we found a global with the same name in the dest module, but it has
-    // internal linkage, we are really not doing any linkage here.
-    if (DGV->hasLocalLinkage())
-      return nullptr;
-
-    // Otherwise, we do in fact link to the destination global.
-    return DGV;
-  }
-
-  void computeTypeMapping();
-
-  Expected<Constant *> linkAppendingVarProto(GlobalVariable *DstGV,
-                                             const GlobalVariable *SrcGV);
-
-  /// Given the GlobaValue \p SGV in the source module, and the matching
-  /// GlobalValue \p DGV (if any), return true if the linker will pull \p SGV
-  /// into the destination module.
-  ///
-  /// Note this code may call the client-provided \p AddLazyFor.
-  bool shouldLink(GlobalValue *DGV, GlobalValue &SGV);
-  Expected<Constant *> linkGlobalValueProto(GlobalValue *GV, bool ForAlias);
-
-  Error linkModuleFlagsMetadata();
-
-  void linkGlobalVariable(GlobalVariable &Dst, GlobalVariable &Src);
-  Error linkFunctionBody(Function &Dst, Function &Src);
-  void linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src);
-  Error linkGlobalValueBody(GlobalValue &Dst, GlobalValue &Src);
-
-  /// Functions that take care of cloning a specific global value type
-  /// into the destination module.
-  GlobalVariable *copyGlobalVariableProto(const GlobalVariable *SGVar);
-  Function *copyFunctionProto(const Function *SF);
-  GlobalValue *copyGlobalAliasProto(const GlobalAlias *SGA);
-
-  /// When importing for ThinLTO, prevent importing of types listed on
-  /// the DICompileUnit that we don't need a copy of in the importing
-  /// module.
-  void prepareCompileUnitsForImport();
-  void linkNamedMDNodes();
-
-public:
-  IRLinker(Module &DstM, MDMapT &SharedMDs,
-           IRMover::IdentifiedStructTypeSet &Set, std::unique_ptr<Module> SrcM,
-           ArrayRef<GlobalValue *> ValuesToLink,
-           std::function<void(GlobalValue &, IRMover::ValueAdder)> AddLazyFor,
-           bool IsPerformingImport)
-      : DstM(DstM), SrcM(std::move(SrcM)), AddLazyFor(std::move(AddLazyFor)),
-        TypeMap(Set), GValMaterializer(*this), LValMaterializer(*this),
-        SharedMDs(SharedMDs), IsPerformingImport(IsPerformingImport),
-        Mapper(ValueMap, RF_MoveDistinctMDs | RF_IgnoreMissingLocals, &TypeMap,
-               &GValMaterializer),
-        AliasMCID(Mapper.registerAlternateMappingContext(AliasValueMap,
-                                                         &LValMaterializer)) {
-    ValueMap.getMDMap() = std::move(SharedMDs);
-    for (GlobalValue *GV : ValuesToLink)
-      maybeAdd(GV);
-    if (IsPerformingImport)
-      prepareCompileUnitsForImport();
-  }
-  ~IRLinker() { SharedMDs = std::move(*ValueMap.getMDMap()); }
-
-  Error run();
-  Value *materialize(Value *V, bool ForAlias);
-};
-}
-
-/// The LLVM SymbolTable class autorenames globals that conflict in the symbol
-/// table. This is good for all clients except for us. Go through the trouble
-/// to force this back.
-static void forceRenaming(GlobalValue *GV, StringRef Name) {
-  // If the global doesn't force its name or if it already has the right name,
-  // there is nothing for us to do.
-  if (GV->hasLocalLinkage() || GV->getName() == Name)
-    return;
-
-  Module *M = GV->getParent();
-
-  // If there is a conflict, rename the conflict.
-  if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
-    GV->takeName(ConflictGV);
-    ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
-    assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
-  } else {
-    GV->setName(Name); // Force the name back
-  }
-}
-
-Value *GlobalValueMaterializer::materialize(Value *SGV) {
-  return TheIRLinker.materialize(SGV, false);
-}
-
-Value *LocalValueMaterializer::materialize(Value *SGV) {
-  return TheIRLinker.materialize(SGV, true);
-}
-
-Value *IRLinker::materialize(Value *V, bool ForAlias) {
-  auto *SGV = dyn_cast<GlobalValue>(V);
-  if (!SGV)
-    return nullptr;
-
-  Expected<Constant *> NewProto = linkGlobalValueProto(SGV, ForAlias);
-  if (!NewProto) {
-    setError(NewProto.takeError());
-    return nullptr;
-  }
-  if (!*NewProto)
-    return nullptr;
-
-  GlobalValue *New = dyn_cast<GlobalValue>(*NewProto);
-  if (!New)
-    return *NewProto;
-
-  // If we already created the body, just return.
-  if (auto *F = dyn_cast<Function>(New)) {
-    if (!F->isDeclaration())
-      return New;
-  } else if (auto *V = dyn_cast<GlobalVariable>(New)) {
-    if (V->hasInitializer() || V->hasAppendingLinkage())
-      return New;
-  } else {
-    auto *A = cast<GlobalAlias>(New);
-    if (A->getAliasee())
-      return New;
-  }
-
-  // When linking a global for an alias, it will always be linked. However we
-  // need to check if it was not already scheduled to satisfy a reference from a
-  // regular global value initializer. We know if it has been schedule if the
-  // "New" GlobalValue that is mapped here for the alias is the same as the one
-  // already mapped. If there is an entry in the ValueMap but the value is
-  // different, it means that the value already had a definition in the
-  // destination module (linkonce for instance), but we need a new definition
-  // for the alias ("New" will be different.
-  if (ForAlias && ValueMap.lookup(SGV) == New)
-    return New;
-
-  if (ForAlias || shouldLink(New, *SGV))
-    setError(linkGlobalValueBody(*New, *SGV));
-
-  return New;
-}
-
-/// Loop through the global variables in the src module and merge them into the
-/// dest module.
-GlobalVariable *IRLinker::copyGlobalVariableProto(const GlobalVariable *SGVar) {
-  // No linking to be performed or linking from the source: simply create an
-  // identical version of the symbol over in the dest module... the
-  // initializer will be filled in later by LinkGlobalInits.
-  GlobalVariable *NewDGV =
-      new GlobalVariable(DstM, TypeMap.get(SGVar->getValueType()),
-                         SGVar->isConstant(), GlobalValue::ExternalLinkage,
-                         /*init*/ nullptr, SGVar->getName(),
-                         /*insertbefore*/ nullptr, SGVar->getThreadLocalMode(),
-                         SGVar->getType()->getAddressSpace());
-  NewDGV->setAlignment(SGVar->getAlignment());
-  NewDGV->copyAttributesFrom(SGVar);
-  return NewDGV;
-}
-
-/// Link the function in the source module into the destination module if
-/// needed, setting up mapping information.
-Function *IRLinker::copyFunctionProto(const Function *SF) {
-  // If there is no linkage to be performed or we are linking from the source,
-  // bring SF over.
-  auto *F =
-      Function::Create(TypeMap.get(SF->getFunctionType()),
-                       GlobalValue::ExternalLinkage, SF->getName(), &DstM);
-  F->copyAttributesFrom(SF);
-  return F;
-}
-
-/// Set up prototypes for any aliases that come over from the source module.
-GlobalValue *IRLinker::copyGlobalAliasProto(const GlobalAlias *SGA) {
-  // If there is no linkage to be performed or we're linking from the source,
-  // bring over SGA.
-  auto *Ty = TypeMap.get(SGA->getValueType());
-  auto *GA =
-      GlobalAlias::create(Ty, SGA->getType()->getPointerAddressSpace(),
-                          GlobalValue::ExternalLinkage, SGA->getName(), &DstM);
-  GA->copyAttributesFrom(SGA);
-  return GA;
-}
-
-GlobalValue *IRLinker::copyGlobalValueProto(const GlobalValue *SGV,
-                                            bool ForDefinition) {
-  GlobalValue *NewGV;
-  if (auto *SGVar = dyn_cast<GlobalVariable>(SGV)) {
-    NewGV = copyGlobalVariableProto(SGVar);
-  } else if (auto *SF = dyn_cast<Function>(SGV)) {
-    NewGV = copyFunctionProto(SF);
-  } else {
-    if (ForDefinition)
-      NewGV = copyGlobalAliasProto(cast<GlobalAlias>(SGV));
-    else if (SGV->getValueType()->isFunctionTy())
-      NewGV =
-          Function::Create(cast<FunctionType>(TypeMap.get(SGV->getValueType())),
-                           GlobalValue::ExternalLinkage, SGV->getName(), &DstM);
-    else
-      NewGV = new GlobalVariable(
-          DstM, TypeMap.get(SGV->getValueType()),
-          /*isConstant*/ false, GlobalValue::ExternalLinkage,
-          /*init*/ nullptr, SGV->getName(),
-          /*insertbefore*/ nullptr, SGV->getThreadLocalMode(),
-          SGV->getType()->getAddressSpace());
-  }
-
-  if (ForDefinition)
-    NewGV->setLinkage(SGV->getLinkage());
-  else if (SGV->hasExternalWeakLinkage())
-    NewGV->setLinkage(GlobalValue::ExternalWeakLinkage);
-
-  if (auto *NewGO = dyn_cast<GlobalObject>(NewGV)) {
-    // Metadata for global variables and function declarations is copied eagerly.
-    if (isa<GlobalVariable>(SGV) || SGV->isDeclaration())
-      NewGO->copyMetadata(cast<GlobalObject>(SGV), 0);
-  }
-
-  // Remove these copied constants in case this stays a declaration, since
-  // they point to the source module. If the def is linked the values will
-  // be mapped in during linkFunctionBody.
-  if (auto *NewF = dyn_cast<Function>(NewGV)) {
-    NewF->setPersonalityFn(nullptr);
-    NewF->setPrefixData(nullptr);
-    NewF->setPrologueData(nullptr);
-  }
-
-  return NewGV;
-}
-
-static StringRef getTypeNamePrefix(StringRef Name) {
-  size_t DotPos = Name.rfind('.');
-  return (DotPos == 0 || DotPos == StringRef::npos || Name.back() == '.' ||
-          !isdigit(static_cast<unsigned char>(Name[DotPos + 1])))
-             ? Name
-             : Name.substr(0, DotPos);
-}
-
-/// Loop over all of the linked values to compute type mappings.  For example,
-/// if we link "extern Foo *x" and "Foo *x = NULL", then we have two struct
-/// types 'Foo' but one got renamed when the module was loaded into the same
-/// LLVMContext.
-void IRLinker::computeTypeMapping() {
-  for (GlobalValue &SGV : SrcM->globals()) {
-    GlobalValue *DGV = getLinkedToGlobal(&SGV);
-    if (!DGV)
-      continue;
-
-    if (!DGV->hasAppendingLinkage() || !SGV.hasAppendingLinkage()) {
-      TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
-      continue;
-    }
-
-    // Unify the element type of appending arrays.
-    ArrayType *DAT = cast<ArrayType>(DGV->getValueType());
-    ArrayType *SAT = cast<ArrayType>(SGV.getValueType());
-    TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
-  }
-
-  for (GlobalValue &SGV : *SrcM)
-    if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
-      TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
-
-  for (GlobalValue &SGV : SrcM->aliases())
-    if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
-      TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
-
-  // Incorporate types by name, scanning all the types in the source module.
-  // At this point, the destination module may have a type "%foo = { i32 }" for
-  // example.  When the source module got loaded into the same LLVMContext, if
-  // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
-  std::vector<StructType *> Types = SrcM->getIdentifiedStructTypes();
-  for (StructType *ST : Types) {
-    if (!ST->hasName())
-      continue;
-
-    if (TypeMap.DstStructTypesSet.hasType(ST)) {
-      // This is actually a type from the destination module.
-      // getIdentifiedStructTypes() can have found it by walking debug info
-      // metadata nodes, some of which get linked by name when ODR Type Uniquing
-      // is enabled on the Context, from the source to the destination module.
-      continue;
-    }
-
-    auto STTypePrefix = getTypeNamePrefix(ST->getName());
-    if (STTypePrefix.size()== ST->getName().size())
-      continue;
-
-    // Check to see if the destination module has a struct with the prefix name.
-    StructType *DST = DstM.getTypeByName(STTypePrefix);
-    if (!DST)
-      continue;
-
-    // Don't use it if this actually came from the source module. They're in
-    // the same LLVMContext after all. Also don't use it unless the type is
-    // actually used in the destination module. This can happen in situations
-    // like this:
-    //
-    //      Module A                         Module B
-    //      --------                         --------
-    //   %Z = type { %A }                %B = type { %C.1 }
-    //   %A = type { %B.1, [7 x i8] }    %C.1 = type { i8* }
-    //   %B.1 = type { %C }              %A.2 = type { %B.3, [5 x i8] }
-    //   %C = type { i8* }               %B.3 = type { %C.1 }
-    //
-    // When we link Module B with Module A, the '%B' in Module B is
-    // used. However, that would then use '%C.1'. But when we process '%C.1',
-    // we prefer to take the '%C' version. So we are then left with both
-    // '%C.1' and '%C' being used for the same types. This leads to some
-    // variables using one type and some using the other.
-    if (TypeMap.DstStructTypesSet.hasType(DST))
-      TypeMap.addTypeMapping(DST, ST);
-  }
-
-  // Now that we have discovered all of the type equivalences, get a body for
-  // any 'opaque' types in the dest module that are now resolved.
-  TypeMap.linkDefinedTypeBodies();
-}
-
-static void getArrayElements(const Constant *C,
-                             SmallVectorImpl<Constant *> &Dest) {
-  unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
-
-  for (unsigned i = 0; i != NumElements; ++i)
-    Dest.push_back(C->getAggregateElement(i));
-}
-
-/// If there were any appending global variables, link them together now.
-Expected<Constant *>
-IRLinker::linkAppendingVarProto(GlobalVariable *DstGV,
-                                const GlobalVariable *SrcGV) {
-  Type *EltTy = cast<ArrayType>(TypeMap.get(SrcGV->getValueType()))
-                    ->getElementType();
-
-  // FIXME: This upgrade is done during linking to support the C API.  Once the
-  // old form is deprecated, we should move this upgrade to
-  // llvm::UpgradeGlobalVariable() and simplify the logic here and in
-  // Mapper::mapAppendingVariable() in ValueMapper.cpp.
-  StringRef Name = SrcGV->getName();
-  bool IsNewStructor = false;
-  bool IsOldStructor = false;
-  if (Name == "llvm.global_ctors" || Name == "llvm.global_dtors") {
-    if (cast<StructType>(EltTy)->getNumElements() == 3)
-      IsNewStructor = true;
-    else
-      IsOldStructor = true;
-  }
-
-  PointerType *VoidPtrTy = Type::getInt8Ty(SrcGV->getContext())->getPointerTo();
-  if (IsOldStructor) {
-    auto &ST = *cast<StructType>(EltTy);
-    Type *Tys[3] = {ST.getElementType(0), ST.getElementType(1), VoidPtrTy};
-    EltTy = StructType::get(SrcGV->getContext(), Tys, false);
-  }
-
-  uint64_t DstNumElements = 0;
-  if (DstGV) {
-    ArrayType *DstTy = cast<ArrayType>(DstGV->getValueType());
-    DstNumElements = DstTy->getNumElements();
-
-    if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
-      return stringErr(
-          "Linking globals named '" + SrcGV->getName() +
-          "': can only link appending global with another appending "
-          "global!");
-
-    // Check to see that they two arrays agree on type.
-    if (EltTy != DstTy->getElementType())
-      return stringErr("Appending variables with different element types!");
-    if (DstGV->isConstant() != SrcGV->isConstant())
-      return stringErr("Appending variables linked with different const'ness!");
-
-    if (DstGV->getAlignment() != SrcGV->getAlignment())
-      return stringErr(
-          "Appending variables with different alignment need to be linked!");
-
-    if (DstGV->getVisibility() != SrcGV->getVisibility())
-      return stringErr(
-          "Appending variables with different visibility need to be linked!");
-
-    if (DstGV->hasGlobalUnnamedAddr() != SrcGV->hasGlobalUnnamedAddr())
-      return stringErr(
-          "Appending variables with different unnamed_addr need to be linked!");
-
-    if (DstGV->getSection() != SrcGV->getSection())
-      return stringErr(
-          "Appending variables with different section name need to be linked!");
-  }
-
-  SmallVector<Constant *, 16> SrcElements;
-  getArrayElements(SrcGV->getInitializer(), SrcElements);
-
-  if (IsNewStructor) {
-    auto It = remove_if(SrcElements, [this](Constant *E) {
-      auto *Key =
-          dyn_cast<GlobalValue>(E->getAggregateElement(2)->stripPointerCasts());
-      if (!Key)
-        return false;
-      GlobalValue *DGV = getLinkedToGlobal(Key);
-      return !shouldLink(DGV, *Key);
-    });
-    SrcElements.erase(It, SrcElements.end());
-  }
-  uint64_t NewSize = DstNumElements + SrcElements.size();
-  ArrayType *NewType = ArrayType::get(EltTy, NewSize);
-
-  // Create the new global variable.
-  GlobalVariable *NG = new GlobalVariable(
-      DstM, NewType, SrcGV->isConstant(), SrcGV->getLinkage(),
-      /*init*/ nullptr, /*name*/ "", DstGV, SrcGV->getThreadLocalMode(),
-      SrcGV->getType()->getAddressSpace());
-
-  NG->copyAttributesFrom(SrcGV);
-  forceRenaming(NG, SrcGV->getName());
-
-  Constant *Ret = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
-
-  Mapper.scheduleMapAppendingVariable(*NG,
-                                      DstGV ? DstGV->getInitializer() : nullptr,
-                                      IsOldStructor, SrcElements);
-
-  // Replace any uses of the two global variables with uses of the new
-  // global.
-  if (DstGV) {
-    DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
-    DstGV->eraseFromParent();
-  }
-
-  return Ret;
-}
-
-bool IRLinker::shouldLink(GlobalValue *DGV, GlobalValue &SGV) {
-  if (ValuesToLink.count(&SGV) || SGV.hasLocalLinkage())
-    return true;
-
-  if (DGV && !DGV->isDeclarationForLinker())
-    return false;
-
-  if (SGV.isDeclaration() || DoneLinkingBodies)
-    return false;
-
-  // Callback to the client to give a chance to lazily add the Global to the
-  // list of value to link.
-  bool LazilyAdded = false;
-  AddLazyFor(SGV, [this, &LazilyAdded](GlobalValue &GV) {
-    maybeAdd(&GV);
-    LazilyAdded = true;
-  });
-  return LazilyAdded;
-}
-
-Expected<Constant *> IRLinker::linkGlobalValueProto(GlobalValue *SGV,
-                                                    bool ForAlias) {
-  GlobalValue *DGV = getLinkedToGlobal(SGV);
-
-  bool ShouldLink = shouldLink(DGV, *SGV);
-
-  // just missing from map
-  if (ShouldLink) {
-    auto I = ValueMap.find(SGV);
-    if (I != ValueMap.end())
-      return cast<Constant>(I->second);
-
-    I = AliasValueMap.find(SGV);
-    if (I != AliasValueMap.end())
-      return cast<Constant>(I->second);
-  }
-
-  if (!ShouldLink && ForAlias)
-    DGV = nullptr;
-
-  // Handle the ultra special appending linkage case first.
-  assert(!DGV || SGV->hasAppendingLinkage() == DGV->hasAppendingLinkage());
-  if (SGV->hasAppendingLinkage())
-    return linkAppendingVarProto(cast_or_null<GlobalVariable>(DGV),
-                                 cast<GlobalVariable>(SGV));
-
-  GlobalValue *NewGV;
-  if (DGV && !ShouldLink) {
-    NewGV = DGV;
-  } else {
-    // If we are done linking global value bodies (i.e. we are performing
-    // metadata linking), don't link in the global value due to this
-    // reference, simply map it to null.
-    if (DoneLinkingBodies)
-      return nullptr;
-
-    NewGV = copyGlobalValueProto(SGV, ShouldLink || ForAlias);
-    if (ShouldLink || !ForAlias)
-      forceRenaming(NewGV, SGV->getName());
-  }
-
-  // Overloaded intrinsics have overloaded types names as part of their
-  // names. If we renamed overloaded types we should rename the intrinsic
-  // as well.
-  if (Function *F = dyn_cast<Function>(NewGV))
-    if (auto Remangled = Intrinsic::remangleIntrinsicFunction(F))
-      NewGV = Remangled.getValue();
-
-  if (ShouldLink || ForAlias) {
-    if (const Comdat *SC = SGV->getComdat()) {
-      if (auto *GO = dyn_cast<GlobalObject>(NewGV)) {
-        Comdat *DC = DstM.getOrInsertComdat(SC->getName());
-        DC->setSelectionKind(SC->getSelectionKind());
-        GO->setComdat(DC);
-      }
-    }
-  }
-
-  if (!ShouldLink && ForAlias)
-    NewGV->setLinkage(GlobalValue::InternalLinkage);
-
-  Constant *C = NewGV;
-  // Only create a bitcast if necessary. In particular, with
-  // DebugTypeODRUniquing we may reach metadata in the destination module
-  // containing a GV from the source module, in which case SGV will be
-  // the same as DGV and NewGV, and TypeMap.get() will assert since it
-  // assumes it is being invoked on a type in the source module.
-  if (DGV && NewGV != SGV) {
-    C = ConstantExpr::getPointerBitCastOrAddrSpaceCast(
-      NewGV, TypeMap.get(SGV->getType()));
-  }
-
-  if (DGV && NewGV != DGV) {
-    DGV->replaceAllUsesWith(
-      ConstantExpr::getPointerBitCastOrAddrSpaceCast(NewGV, DGV->getType()));
-    DGV->eraseFromParent();
-  }
-
-  return C;
-}
-
-/// Update the initializers in the Dest module now that all globals that may be
-/// referenced are in Dest.
-void IRLinker::linkGlobalVariable(GlobalVariable &Dst, GlobalVariable &Src) {
-  // Figure out what the initializer looks like in the dest module.
-  Mapper.scheduleMapGlobalInitializer(Dst, *Src.getInitializer());
-}
-
-/// Copy the source function over into the dest function and fix up references
-/// to values. At this point we know that Dest is an external function, and
-/// that Src is not.
-Error IRLinker::linkFunctionBody(Function &Dst, Function &Src) {
-  assert(Dst.isDeclaration() && !Src.isDeclaration());
-
-  // Materialize if needed.
-  if (Error Err = Src.materialize())
-    return Err;
-
-  // Link in the operands without remapping.
-  if (Src.hasPrefixData())
-    Dst.setPrefixData(Src.getPrefixData());
-  if (Src.hasPrologueData())
-    Dst.setPrologueData(Src.getPrologueData());
-  if (Src.hasPersonalityFn())
-    Dst.setPersonalityFn(Src.getPersonalityFn());
-
-  // Copy over the metadata attachments without remapping.
-  Dst.copyMetadata(&Src, 0);
-
-  // Steal arguments and splice the body of Src into Dst.
-  Dst.stealArgumentListFrom(Src);
-  Dst.getBasicBlockList().splice(Dst.end(), Src.getBasicBlockList());
-
-  // Everything has been moved over.  Remap it.
-  Mapper.scheduleRemapFunction(Dst);
-  return Error::success();
-}
-
-void IRLinker::linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src) {
-  Mapper.scheduleMapGlobalAliasee(Dst, *Src.getAliasee(), AliasMCID);
-}
-
-Error IRLinker::linkGlobalValueBody(GlobalValue &Dst, GlobalValue &Src) {
-  if (auto *F = dyn_cast<Function>(&Src))
-    return linkFunctionBody(cast<Function>(Dst), *F);
-  if (auto *GVar = dyn_cast<GlobalVariable>(&Src)) {
-    linkGlobalVariable(cast<GlobalVariable>(Dst), *GVar);
-    return Error::success();
-  }
-  linkAliasBody(cast<GlobalAlias>(Dst), cast<GlobalAlias>(Src));
-  return Error::success();
-}
-
-void IRLinker::prepareCompileUnitsForImport() {
-  NamedMDNode *SrcCompileUnits = SrcM->getNamedMetadata("llvm.dbg.cu");
-  if (!SrcCompileUnits)
-    return;
-  // When importing for ThinLTO, prevent importing of types listed on
-  // the DICompileUnit that we don't need a copy of in the importing
-  // module. They will be emitted by the originating module.
-  for (unsigned I = 0, E = SrcCompileUnits->getNumOperands(); I != E; ++I) {
-    auto *CU = cast<DICompileUnit>(SrcCompileUnits->getOperand(I));
-    assert(CU && "Expected valid compile unit");
-    // Enums, macros, and retained types don't need to be listed on the
-    // imported DICompileUnit. This means they will only be imported
-    // if reached from the mapped IR. Do this by setting their value map
-    // entries to nullptr, which will automatically prevent their importing
-    // when reached from the DICompileUnit during metadata mapping.
-    ValueMap.MD()[CU->getRawEnumTypes()].reset(nullptr);
-    ValueMap.MD()[CU->getRawMacros()].reset(nullptr);
-    ValueMap.MD()[CU->getRawRetainedTypes()].reset(nullptr);
-    // The original definition (or at least its debug info - if the variable is
-    // internalized an optimized away) will remain in the source module, so
-    // there's no need to import them.
-    // If LLVM ever does more advanced optimizations on global variables
-    // (removing/localizing write operations, for instance) that can track
-    // through debug info, this decision may need to be revisited - but do so
-    // with care when it comes to debug info size. Emitting small CUs containing
-    // only a few imported entities into every destination module may be very
-    // size inefficient.
-    ValueMap.MD()[CU->getRawGlobalVariables()].reset(nullptr);
-
-    // Imported entities only need to be mapped in if they have local
-    // scope, as those might correspond to an imported entity inside a
-    // function being imported (any locally scoped imported entities that
-    // don't end up referenced by an imported function will not be emitted
-    // into the object). Imported entities not in a local scope
-    // (e.g. on the namespace) only need to be emitted by the originating
-    // module. Create a list of the locally scoped imported entities, and
-    // replace the source CUs imported entity list with the new list, so
-    // only those are mapped in.
-    // FIXME: Locally-scoped imported entities could be moved to the
-    // functions they are local to instead of listing them on the CU, and
-    // we would naturally only link in those needed by function importing.
-    SmallVector<TrackingMDNodeRef, 4> AllImportedModules;
-    bool ReplaceImportedEntities = false;
-    for (auto *IE : CU->getImportedEntities()) {
-      DIScope *Scope = IE->getScope();
-      assert(Scope && "Invalid Scope encoding!");
-      if (isa<DILocalScope>(Scope))
-        AllImportedModules.emplace_back(IE);
-      else
-        ReplaceImportedEntities = true;
-    }
-    if (ReplaceImportedEntities) {
-      if (!AllImportedModules.empty())
-        CU->replaceImportedEntities(MDTuple::get(
-            CU->getContext(),
-            SmallVector<Metadata *, 16>(AllImportedModules.begin(),
-                                        AllImportedModules.end())));
-      else
-        // If there were no local scope imported entities, we can map
-        // the whole list to nullptr.
-        ValueMap.MD()[CU->getRawImportedEntities()].reset(nullptr);
-    }
-  }
-}
-
-/// Insert all of the named MDNodes in Src into the Dest module.
-void IRLinker::linkNamedMDNodes() {
-  const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
-  for (const NamedMDNode &NMD : SrcM->named_metadata()) {
-    // Don't link module flags here. Do them separately.
-    if (&NMD == SrcModFlags)
-      continue;
-    NamedMDNode *DestNMD = DstM.getOrInsertNamedMetadata(NMD.getName());
-    // Add Src elements into Dest node.
-    for (const MDNode *Op : NMD.operands())
-      DestNMD->addOperand(Mapper.mapMDNode(*Op));
-  }
-}
-
-/// Merge the linker flags in Src into the Dest module.
-Error IRLinker::linkModuleFlagsMetadata() {
-  // If the source module has no module flags, we are done.
-  const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
-  if (!SrcModFlags)
-    return Error::success();
-
-  // If the destination module doesn't have module flags yet, then just copy
-  // over the source module's flags.
-  NamedMDNode *DstModFlags = DstM.getOrInsertModuleFlagsMetadata();
-  if (DstModFlags->getNumOperands() == 0) {
-    for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
-      DstModFlags->addOperand(SrcModFlags->getOperand(I));
-
-    return Error::success();
-  }
-
-  // First build a map of the existing module flags and requirements.
-  DenseMap<MDString *, std::pair<MDNode *, unsigned>> Flags;
-  SmallSetVector<MDNode *, 16> Requirements;
-  for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) {
-    MDNode *Op = DstModFlags->getOperand(I);
-    ConstantInt *Behavior = mdconst::extract<ConstantInt>(Op->getOperand(0));
-    MDString *ID = cast<MDString>(Op->getOperand(1));
-
-    if (Behavior->getZExtValue() == Module::Require) {
-      Requirements.insert(cast<MDNode>(Op->getOperand(2)));
-    } else {
-      Flags[ID] = std::make_pair(Op, I);
-    }
-  }
-
-  // Merge in the flags from the source module, and also collect its set of
-  // requirements.
-  for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) {
-    MDNode *SrcOp = SrcModFlags->getOperand(I);
-    ConstantInt *SrcBehavior =
-        mdconst::extract<ConstantInt>(SrcOp->getOperand(0));
-    MDString *ID = cast<MDString>(SrcOp->getOperand(1));
-    MDNode *DstOp;
-    unsigned DstIndex;
-    std::tie(DstOp, DstIndex) = Flags.lookup(ID);
-    unsigned SrcBehaviorValue = SrcBehavior->getZExtValue();
-
-    // If this is a requirement, add it and continue.
-    if (SrcBehaviorValue == Module::Require) {
-      // If the destination module does not already have this requirement, add
-      // it.
-      if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) {
-        DstModFlags->addOperand(SrcOp);
-      }
-      continue;
-    }
-
-    // If there is no existing flag with this ID, just add it.
-    if (!DstOp) {
-      Flags[ID] = std::make_pair(SrcOp, DstModFlags->getNumOperands());
-      DstModFlags->addOperand(SrcOp);
-      continue;
-    }
-
-    // Otherwise, perform a merge.
-    ConstantInt *DstBehavior =
-        mdconst::extract<ConstantInt>(DstOp->getOperand(0));
-    unsigned DstBehaviorValue = DstBehavior->getZExtValue();
-
-    auto overrideDstValue = [&]() {
-      DstModFlags->setOperand(DstIndex, SrcOp);
-      Flags[ID].first = SrcOp;
-    };
-
-    // If either flag has override behavior, handle it first.
-    if (DstBehaviorValue == Module::Override) {
-      // Diagnose inconsistent flags which both have override behavior.
-      if (SrcBehaviorValue == Module::Override &&
-          SrcOp->getOperand(2) != DstOp->getOperand(2))
-        return stringErr("linking module flags '" + ID->getString() +
-                         "': IDs have conflicting override values");
-      continue;
-    } else if (SrcBehaviorValue == Module::Override) {
-      // Update the destination flag to that of the source.
-      overrideDstValue();
-      continue;
-    }
-
-    // Diagnose inconsistent merge behavior types.
-    if (SrcBehaviorValue != DstBehaviorValue)
-      return stringErr("linking module flags '" + ID->getString() +
-                       "': IDs have conflicting behaviors");
-
-    auto replaceDstValue = [&](MDNode *New) {
-      Metadata *FlagOps[] = {DstOp->getOperand(0), ID, New};
-      MDNode *Flag = MDNode::get(DstM.getContext(), FlagOps);
-      DstModFlags->setOperand(DstIndex, Flag);
-      Flags[ID].first = Flag;
-    };
-
-    // Perform the merge for standard behavior types.
-    switch (SrcBehaviorValue) {
-    case Module::Require:
-    case Module::Override:
-      llvm_unreachable("not possible");
-    case Module::Error: {
-      // Emit an error if the values differ.
-      if (SrcOp->getOperand(2) != DstOp->getOperand(2))
-        return stringErr("linking module flags '" + ID->getString() +
-                         "': IDs have conflicting values");
-      continue;
-    }
-    case Module::Warning: {
-      // Emit a warning if the values differ.
-      if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
-        std::string str;
-        raw_string_ostream(str)
-            << "linking module flags '" << ID->getString()
-            << "': IDs have conflicting values ('" << *SrcOp->getOperand(2)
-            << "' from " << SrcM->getModuleIdentifier() << " with '"
-            << *DstOp->getOperand(2) << "' from " << DstM.getModuleIdentifier()
-            << ')';
-        emitWarning(str);
-      }
-      continue;
-    }
-    case Module::Max: {
-      ConstantInt *DstValue =
-          mdconst::extract<ConstantInt>(DstOp->getOperand(2));
-      ConstantInt *SrcValue =
-          mdconst::extract<ConstantInt>(SrcOp->getOperand(2));
-      if (SrcValue->getZExtValue() > DstValue->getZExtValue())
-        overrideDstValue();
-      break;
-    }
-    case Module::Append: {
-      MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
-      MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
-      SmallVector<Metadata *, 8> MDs;
-      MDs.reserve(DstValue->getNumOperands() + SrcValue->getNumOperands());
-      MDs.append(DstValue->op_begin(), DstValue->op_end());
-      MDs.append(SrcValue->op_begin(), SrcValue->op_end());
-
-      replaceDstValue(MDNode::get(DstM.getContext(), MDs));
-      break;
-    }
-    case Module::AppendUnique: {
-      SmallSetVector<Metadata *, 16> Elts;
-      MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
-      MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
-      Elts.insert(DstValue->op_begin(), DstValue->op_end());
-      Elts.insert(SrcValue->op_begin(), SrcValue->op_end());
-
-      replaceDstValue(MDNode::get(DstM.getContext(),
-                                  makeArrayRef(Elts.begin(), Elts.end())));
-      break;
-    }
-    }
-  }
-
-  // Check all of the requirements.
-  for (unsigned I = 0, E = Requirements.size(); I != E; ++I) {
-    MDNode *Requirement = Requirements[I];
-    MDString *Flag = cast<MDString>(Requirement->getOperand(0));
-    Metadata *ReqValue = Requirement->getOperand(1);
-
-    MDNode *Op = Flags[Flag].first;
-    if (!Op || Op->getOperand(2) != ReqValue)
-      return stringErr("linking module flags '" + Flag->getString() +
-                       "': does not have the required value");
-  }
-  return Error::success();
-}
-
-/// Return InlineAsm adjusted with target-specific directives if required.
-/// For ARM and Thumb, we have to add directives to select the appropriate ISA
-/// to support mixing module-level inline assembly from ARM and Thumb modules.
-static std::string adjustInlineAsm(const std::string &InlineAsm,
-                                   const Triple &Triple) {
-  if (Triple.getArch() == Triple::thumb || Triple.getArch() == Triple::thumbeb)
-    return ".text\n.balign 2\n.thumb\n" + InlineAsm;
-  if (Triple.getArch() == Triple::arm || Triple.getArch() == Triple::armeb)
-    return ".text\n.balign 4\n.arm\n" + InlineAsm;
-  return InlineAsm;
-}
-
-Error IRLinker::run() {
-  // Ensure metadata materialized before value mapping.
-  if (SrcM->getMaterializer())
-    if (Error Err = SrcM->getMaterializer()->materializeMetadata())
-      return Err;
-
-  // Inherit the target data from the source module if the destination module
-  // doesn't have one already.
-  if (DstM.getDataLayout().isDefault())
-    DstM.setDataLayout(SrcM->getDataLayout());
-
-  if (SrcM->getDataLayout() != DstM.getDataLayout()) {
-    emitWarning("Linking two modules of different data layouts: '" +
-                SrcM->getModuleIdentifier() + "' is '" +
-                SrcM->getDataLayoutStr() + "' whereas '" +
-                DstM.getModuleIdentifier() + "' is '" +
-                DstM.getDataLayoutStr() + "'\n");
-  }
-
-  // Copy the target triple from the source to dest if the dest's is empty.
-  if (DstM.getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
-    DstM.setTargetTriple(SrcM->getTargetTriple());
-
-  Triple SrcTriple(SrcM->getTargetTriple()), DstTriple(DstM.getTargetTriple());
-
-  if (!SrcM->getTargetTriple().empty()&&
-      !SrcTriple.isCompatibleWith(DstTriple))
-    emitWarning("Linking two modules of different target triples: " +
-                SrcM->getModuleIdentifier() + "' is '" +
-                SrcM->getTargetTriple() + "' whereas '" +
-                DstM.getModuleIdentifier() + "' is '" + DstM.getTargetTriple() +
-                "'\n");
-
-  DstM.setTargetTriple(SrcTriple.merge(DstTriple));
-
-  // Append the module inline asm string.
-  if (!IsPerformingImport && !SrcM->getModuleInlineAsm().empty()) {
-    std::string SrcModuleInlineAsm = adjustInlineAsm(SrcM->getModuleInlineAsm(),
-                                                     SrcTriple);
-    if (DstM.getModuleInlineAsm().empty())
-      DstM.setModuleInlineAsm(SrcModuleInlineAsm);
-    else
-      DstM.setModuleInlineAsm(DstM.getModuleInlineAsm() + "\n" +
-                              SrcModuleInlineAsm);
-  }
-
-  // Loop over all of the linked values to compute type mappings.
-  computeTypeMapping();
-
-  std::reverse(Worklist.begin(), Worklist.end());
-  while (!Worklist.empty()) {
-    GlobalValue *GV = Worklist.back();
-    Worklist.pop_back();
-
-    // Already mapped.
-    if (ValueMap.find(GV) != ValueMap.end() ||
-        AliasValueMap.find(GV) != AliasValueMap.end())
-      continue;
-
-    assert(!GV->isDeclaration());
-    Mapper.mapValue(*GV);
-    if (FoundError)
-      return std::move(*FoundError);
-  }
-
-  // Note that we are done linking global value bodies. This prevents
-  // metadata linking from creating new references.
-  DoneLinkingBodies = true;
-  Mapper.addFlags(RF_NullMapMissingGlobalValues);
-
-  // Remap all of the named MDNodes in Src into the DstM module. We do this
-  // after linking GlobalValues so that MDNodes that reference GlobalValues
-  // are properly remapped.
-  linkNamedMDNodes();
-
-  // Merge the module flags into the DstM module.
-  return linkModuleFlagsMetadata();
-}
-
-IRMover::StructTypeKeyInfo::KeyTy::KeyTy(ArrayRef<Type *> E, bool P)
-    : ETypes(E), IsPacked(P) {}
-
-IRMover::StructTypeKeyInfo::KeyTy::KeyTy(const StructType *ST)
-    : ETypes(ST->elements()), IsPacked(ST->isPacked()) {}
-
-bool IRMover::StructTypeKeyInfo::KeyTy::operator==(const KeyTy &That) const {
-  return IsPacked == That.IsPacked && ETypes == That.ETypes;
-}
-
-bool IRMover::StructTypeKeyInfo::KeyTy::operator!=(const KeyTy &That) const {
-  return !this->operator==(That);
-}
-
-StructType *IRMover::StructTypeKeyInfo::getEmptyKey() {
-  return DenseMapInfo<StructType *>::getEmptyKey();
-}
-
-StructType *IRMover::StructTypeKeyInfo::getTombstoneKey() {
-  return DenseMapInfo<StructType *>::getTombstoneKey();
-}
-
-unsigned IRMover::StructTypeKeyInfo::getHashValue(const KeyTy &Key) {
-  return hash_combine(hash_combine_range(Key.ETypes.begin(), Key.ETypes.end()),
-                      Key.IsPacked);
-}
-
-unsigned IRMover::StructTypeKeyInfo::getHashValue(const StructType *ST) {
-  return getHashValue(KeyTy(ST));
-}
-
-bool IRMover::StructTypeKeyInfo::isEqual(const KeyTy &LHS,
-                                         const StructType *RHS) {
-  if (RHS == getEmptyKey() || RHS == getTombstoneKey())
-    return false;
-  return LHS == KeyTy(RHS);
-}
-
-bool IRMover::StructTypeKeyInfo::isEqual(const StructType *LHS,
-                                         const StructType *RHS) {
-  if (RHS == getEmptyKey() || RHS == getTombstoneKey())
-    return LHS == RHS;
-  return KeyTy(LHS) == KeyTy(RHS);
-}
-
-void IRMover::IdentifiedStructTypeSet::addNonOpaque(StructType *Ty) {
-  assert(!Ty->isOpaque());
-  NonOpaqueStructTypes.insert(Ty);
-}
-
-void IRMover::IdentifiedStructTypeSet::switchToNonOpaque(StructType *Ty) {
-  assert(!Ty->isOpaque());
-  NonOpaqueStructTypes.insert(Ty);
-  bool Removed = OpaqueStructTypes.erase(Ty);
-  (void)Removed;
-  assert(Removed);
-}
-
-void IRMover::IdentifiedStructTypeSet::addOpaque(StructType *Ty) {
-  assert(Ty->isOpaque());
-  OpaqueStructTypes.insert(Ty);
-}
-
-StructType *
-IRMover::IdentifiedStructTypeSet::findNonOpaque(ArrayRef<Type *> ETypes,
-                                                bool IsPacked) {
-  IRMover::StructTypeKeyInfo::KeyTy Key(ETypes, IsPacked);
-  auto I = NonOpaqueStructTypes.find_as(Key);
-  return I == NonOpaqueStructTypes.end() ? nullptr : *I;
-}
-
-bool IRMover::IdentifiedStructTypeSet::hasType(StructType *Ty) {
-  if (Ty->isOpaque())
-    return OpaqueStructTypes.count(Ty);
-  auto I = NonOpaqueStructTypes.find(Ty);
-  return I == NonOpaqueStructTypes.end() ? false : *I == Ty;
-}
-
-IRMover::IRMover(Module &M) : Composite(M) {
-  TypeFinder StructTypes;
-  StructTypes.run(M, /* OnlyNamed */ false);
-  for (StructType *Ty : StructTypes) {
-    if (Ty->isOpaque())
-      IdentifiedStructTypes.addOpaque(Ty);
-    else
-      IdentifiedStructTypes.addNonOpaque(Ty);
-  }
-  // Self-map metadatas in the destination module. This is needed when
-  // DebugTypeODRUniquing is enabled on the LLVMContext, since metadata in the
-  // destination module may be reached from the source module.
-  for (auto *MD : StructTypes.getVisitedMetadata()) {
-    SharedMDs[MD].reset(const_cast<MDNode *>(MD));
-  }
-}
-
-Error IRMover::move(
-    std::unique_ptr<Module> Src, ArrayRef<GlobalValue *> ValuesToLink,
-    std::function<void(GlobalValue &, ValueAdder Add)> AddLazyFor,
-    bool IsPerformingImport) {
-  IRLinker TheIRLinker(Composite, SharedMDs, IdentifiedStructTypes,
-                       std::move(Src), ValuesToLink, std::move(AddLazyFor),
-                       IsPerformingImport);
-  Error E = TheIRLinker.run();
-  Composite.dropTriviallyDeadConstantArrays();
-  return E;
-}