Index: llvm/include/llvm/ExecutionEngine/Orc/ExecutionUtils.h
===================================================================
--- llvm/include/llvm/ExecutionEngine/Orc/ExecutionUtils.h
+++ llvm/include/llvm/ExecutionEngine/Orc/ExecutionUtils.h
@@ -18,6 +18,7 @@
 #include "llvm/ExecutionEngine/JITSymbol.h"
 #include "llvm/ExecutionEngine/Orc/Core.h"
 #include "llvm/ExecutionEngine/Orc/Mangling.h"
+#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
 #include "llvm/ExecutionEngine/Orc/Shared/OrcError.h"
 #include "llvm/ExecutionEngine/RuntimeDyld.h"
 #include "llvm/Object/Archive.h"
@@ -314,6 +315,39 @@
   DenseMap<SymbolStringPtr, MemoryBufferRef> ObjectFilesMap;
 };
 
+/// A utility class to create COFF dllimport GOT symbols (__imp_*) and PLT
+/// stubs.
+///
+/// If an instance of this class is attached to a JITDylib as a fallback
+/// definition generator, PLT stubs and dllimport __imp_ symbols will be
+/// generated for external symbols found outside the given jitdylib.
+class DLLImportDefinitionGenerator : public DefinitionGenerator {
+public:
+  /// Creates a DLLImportDefinitionGenerator instance.
+  static std::unique_ptr<DLLImportDefinitionGenerator>
+  Create(ExecutionSession &ES, ObjectLinkingLayer &L);
+
+  Error tryToGenerate(LookupState &LS, LookupKind K, JITDylib &JD,
+                      JITDylibLookupFlags JDLookupFlags,
+                      const SymbolLookupSet &Symbols) override;
+
+private:
+  DLLImportDefinitionGenerator(ExecutionSession &ES, ObjectLinkingLayer &L)
+      : ES(ES), L(L) {}
+
+  static Expected<unsigned> getTargetPointerSize(const Triple &TT);
+  static Expected<support::endianness> getTargetEndianness(const Triple &TT);
+  Expected<std::unique_ptr<jitlink::LinkGraph>>
+  createStubsGraph(const SymbolMap &Resolved);
+
+  static StringRef getImpPrefix() { return "__imp_"; }
+
+  static StringRef getSectionName() { return "$__DLLIMPORT_STUBS"; }
+
+  ExecutionSession &ES;
+  ObjectLinkingLayer &L;
+};
+
 } // end namespace orc
 } // end namespace llvm
 
Index: llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp
===================================================================
--- llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp
+++ llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ExecutionEngine/Orc/ExecutionUtils.h"
+#include "llvm/ExecutionEngine/JITLink/x86_64.h"
 #include "llvm/ExecutionEngine/Orc/Layer.h"
 #include "llvm/ExecutionEngine/Orc/ObjectFileInterface.h"
 #include "llvm/IR/Constants.h"
@@ -350,7 +351,6 @@
 Error StaticLibraryDefinitionGenerator::tryToGenerate(
     LookupState &LS, LookupKind K, JITDylib &JD,
     JITDylibLookupFlags JDLookupFlags, const SymbolLookupSet &Symbols) {
-
   // Don't materialize symbols from static archives unless this is a static
   // lookup.
   if (K != LookupKind::Static)
@@ -430,5 +430,121 @@
     Err = buildObjectFilesMap();
 }
 
+std::unique_ptr<DLLImportDefinitionGenerator>
+DLLImportDefinitionGenerator::Create(ExecutionSession &ES,
+                                     ObjectLinkingLayer &L) {
+  return std::unique_ptr<DLLImportDefinitionGenerator>(
+      new DLLImportDefinitionGenerator(ES, L));
+}
+
+Error DLLImportDefinitionGenerator::tryToGenerate(
+    LookupState &LS, LookupKind K, JITDylib &JD,
+    JITDylibLookupFlags JDLookupFlags, const SymbolLookupSet &Symbols) {
+  JITDylibSearchOrder LinkOrder;
+  JD.withLinkOrderDo([&](const JITDylibSearchOrder &LO) {
+    LinkOrder.reserve(LO.size());
+    for (auto &KV : LO) {
+      if (KV.first == &JD)
+        continue;
+      LinkOrder.push_back(KV);
+    }
+  });
+
+  // FIXME: if regular symbol name start with __imp_ we have to issue lookup of
+  // both __imp_ and stripped name and use the lookup information to resolve the
+  // real symbol name.
+  SymbolLookupSet LookupSet;
+  DenseMap<StringRef, SymbolLookupFlags> ToLookUpSymbols;
+  for (auto &KV : Symbols) {
+    StringRef Deinterned = *KV.first;
+    if (Deinterned.startswith(getImpPrefix()))
+      Deinterned = Deinterned.drop_front(StringRef(getImpPrefix()).size());
+    // Don't degrade the required state
+    if (ToLookUpSymbols.count(Deinterned) &&
+        ToLookUpSymbols[Deinterned] == SymbolLookupFlags::RequiredSymbol)
+      continue;
+    ToLookUpSymbols[Deinterned] = KV.second;
+  }
+
+  for (auto &KV : ToLookUpSymbols)
+    LookupSet.add(ES.intern(KV.first), KV.second);
+
+  auto Resolved =
+      ES.lookup(LinkOrder, LookupSet, LookupKind::DLSym, SymbolState::Resolved);
+  if (!Resolved)
+    return Resolved.takeError();
+
+  auto G = createStubsGraph(*Resolved);
+  if (!G)
+    return G.takeError();
+  return L.add(JD, std::move(*G));
+}
+
+Expected<unsigned>
+DLLImportDefinitionGenerator::getTargetPointerSize(const Triple &TT) {
+  switch (TT.getArch()) {
+  case Triple::x86_64:
+    return 8;
+  default:
+    return make_error<StringError>(
+        "architecture unsupported by DLLImportDefinitionGenerator",
+        inconvertibleErrorCode());
+  }
+}
+
+Expected<support::endianness>
+DLLImportDefinitionGenerator::getTargetEndianness(const Triple &TT) {
+  switch (TT.getArch()) {
+  case Triple::x86_64:
+    return support::endianness::little;
+  default:
+    return make_error<StringError>(
+        "architecture unsupported by DLLImportDefinitionGenerator",
+        inconvertibleErrorCode());
+  }
+}
+
+Expected<std::unique_ptr<jitlink::LinkGraph>>
+DLLImportDefinitionGenerator::createStubsGraph(const SymbolMap &Resolved) {
+  Triple TT = ES.getExecutorProcessControl().getTargetTriple();
+  auto PointerSize = getTargetEndianness(TT);
+  if (!PointerSize)
+    return std::move(PointerSize.takeError());
+  auto Endianness = getTargetEndianness(TT);
+  if (!Endianness)
+    return std::move(Endianness.takeError());
+
+  auto G = std::make_unique<jitlink::LinkGraph>(
+      "<DLLIMPORT_STUBS>", TT, *PointerSize, *Endianness,
+      jitlink::getGenericEdgeKindName);
+  jitlink::Section &Sec = G->createSection(
+      getSectionName(), jitlink::MemProt::Read | jitlink::MemProt::Exec);
+
+  for (auto &KV : Resolved) {
+    jitlink::Symbol &Target = G->addAbsoluteSymbol(
+        *KV.first, ExecutorAddr(KV.second.getAddress()), *PointerSize,
+        jitlink::Linkage::Strong, jitlink::Scope::Local, false);
+
+    // Create __imp_ symbol
+    jitlink::Symbol &Ptr =
+        jitlink::x86_64::createAnonymousPointer(*G, Sec, &Target);
+    auto NameCopy = G->allocateString(Twine(getImpPrefix()) + *KV.first);
+    StringRef NameCopyRef = StringRef(NameCopy.data(), NameCopy.size());
+    Ptr.setName(NameCopyRef);
+    Ptr.setLinkage(jitlink::Linkage::Strong);
+    Ptr.setScope(jitlink::Scope::Default);
+
+    // Create PLT stub
+    // FIXME: check PLT stub of data symbol is not accessed
+    jitlink::Block &StubBlock =
+        jitlink::x86_64::createPointerJumpStubBlock(*G, Sec, Ptr);
+    G->addDefinedSymbol(StubBlock, 0, *KV.first, StubBlock.getSize(),
+                        jitlink::Linkage::Strong, jitlink::Scope::Default, true,
+                        false);
+  }
+
+  return std::move(G);
+}
+
 } // End namespace orc.
 } // End namespace llvm.