Index: lib/Transforms/IPO/LowerTypeTests.cpp
===================================================================
--- lib/Transforms/IPO/LowerTypeTests.cpp
+++ lib/Transforms/IPO/LowerTypeTests.cpp
@@ -956,6 +956,18 @@
     FDecl = Function::Create(F->getFunctionType(), GlobalValue::ExternalLinkage,
                              Name, &M);
     FDecl->setVisibility(Visibility);
+
+    // Delete aliases pointing to this function, they'll be re-created in the
+    // merged output
+    for (auto &U : F->uses()) {
+      if (auto *A = dyn_cast<GlobalAlias>(U.getUser())) {
+        Function *AliasDecl = Function::Create(
+            F->getFunctionType(), GlobalValue::ExternalLinkage, "", &M);
+        AliasDecl->takeName(A);
+        A->replaceAllUsesWith(AliasDecl);
+        A->eraseFromParent();
+      }
+    }
   } else {
     // Function definition without type metadata, where some other translation
     // unit contained a declaration with type metadata. This normally happens
@@ -1673,6 +1685,49 @@
     }
   }
 
+  // Parse alias data to 1) remove aliases from the list of exported functions
+  // and 2) save which aliases should be created after the jump table functions
+  // they point to are created.
+  struct AliasInfo {
+    StringRef AliasName;
+    StringRef Aliasee;
+    GlobalValue::VisibilityTypes Visibility;
+    bool Weak;
+  };
+  std::vector<AliasInfo> Aliases;
+  if (ExportSummary) {
+    if (NamedMDNode *AliasesMD = M.getNamedMetadata("aliases")) {
+      for (auto AliasMD : AliasesMD->operands()) {
+        assert(AliasMD->getNumOperands() >= 4);
+        StringRef AliasName =
+            cast<MDString>(AliasMD->getOperand(0))->getString();
+        StringRef Aliasee = cast<MDString>(AliasMD->getOperand(1))->getString();
+        if (!ExportedFunctions.count(Aliasee) ||
+            ExportedFunctions[Aliasee].Linkage != CFL_Definition)
+          continue;
+
+        if (ExportedFunctions.count(AliasName)) {
+          ExportedFunctions.erase(AliasName);
+          M.getFunction(AliasName)->removeFromParent();
+        }
+
+        GlobalValue::VisibilityTypes Visibility =
+            static_cast<GlobalValue::VisibilityTypes>(
+                cast<ConstantAsMetadata>(AliasMD->getOperand(2))
+                    ->getValue()
+                    ->getUniqueInteger()
+                    .getZExtValue());
+        bool Weak =
+            static_cast<bool>(cast<ConstantAsMetadata>(AliasMD->getOperand(3))
+                                  ->getValue()
+                                  ->getUniqueInteger()
+                                  .getZExtValue());
+
+        Aliases.push_back({AliasName, Aliasee, Visibility, Weak});
+      }
+    }
+  }
+
   for (GlobalObject &GO : M.global_objects()) {
     if (isa<GlobalVariable>(GO) && GO.isDeclarationForLinker())
       continue;
@@ -1804,6 +1859,18 @@
 
   allocateByteArrays();
 
+  std::sort(Aliases.begin(), Aliases.end(), [](AliasInfo A1, AliasInfo A2) {
+    return A1.AliasName.equals_lower(A2.AliasName);
+  });
+  for (auto &A : Aliases) {
+    if (!M.getNamedAlias(A.Aliasee))
+      continue;
+    auto *Alias = GlobalAlias::create(A.AliasName, M.getNamedAlias(A.Aliasee));
+    Alias->setVisibility(A.Visibility);
+    if (A.Weak)
+      Alias->setLinkage(GlobalValue::WeakAnyLinkage);
+  }
+
   return true;
 }
 
Index: lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
===================================================================
--- lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
+++ lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
@@ -357,6 +357,31 @@
       NMD->addOperand(MD);
   }
 
+  SmallVector<MDNode *, 8> FunctionAliases;
+  for (auto &A : M.aliases()) {
+    if (!isa<Function>(A.getAliasee()))
+      continue;
+
+    auto *F = cast<Function>(A.getAliasee());
+    auto &Ctx = MergedM->getContext();
+    SmallVector<Metadata *, 4> Elts;
+
+    Elts.push_back(MDString::get(Ctx, A.getName()));
+    Elts.push_back(MDString::get(Ctx, F->getName()));
+    Elts.push_back(ConstantAsMetadata::get(
+        llvm::ConstantInt::get(Type::getInt8Ty(Ctx), A.getVisibility())));
+    Elts.push_back(ConstantAsMetadata::get(
+        llvm::ConstantInt::get(Type::getInt8Ty(Ctx), A.isWeakForLinker())));
+
+    FunctionAliases.push_back(MDTuple::get(Ctx, Elts));
+  }
+
+  if (!FunctionAliases.empty()) {
+    NamedMDNode *NMD = MergedM->getOrInsertNamedMetadata("aliases");
+    for (auto MD : FunctionAliases)
+      NMD->addOperand(MD);
+  }
+
   simplifyExternals(*MergedM);
 
   // FIXME: Try to re-use BSI and PFI from the original module here.
Index: test/Transforms/LowerTypeTests/Inputs/import-alias.yaml
===================================================================
--- /dev/null
+++ test/Transforms/LowerTypeTests/Inputs/import-alias.yaml
@@ -0,0 +1,11 @@
+---
+TypeIdMap:
+  typeid1:
+    TTRes:
+      Kind:            AllOnes
+      SizeM1BitWidth:  7
+WithGlobalValueDeadStripping: false
+CfiFunctionDefs:
+  - f
+CfiFunctionDecls:
+...
Index: test/Transforms/LowerTypeTests/export-alias.ll
===================================================================
--- /dev/null
+++ test/Transforms/LowerTypeTests/export-alias.ll
@@ -0,0 +1,21 @@
+; RUN: opt -S %s -lowertypetests -lowertypetests-summary-action=export -lowertypetests-read-summary=%S/Inputs/use-typeid1-typeid2.yaml | FileCheck %s
+;
+; CHECK: @alias1 = weak alias void (), void ()* @f
+; CHECK: @alias2 = hidden alias void (), void ()* @f
+; CHECK: declare !type !1 void @alias3()
+; CHECK-NOT: @alias3 = alias
+
+target triple = "x86_64-unknown-linux"
+
+!cfi.functions = !{!0, !2, !3}
+!aliases = !{!4, !5, !6}
+
+!0 = !{!"f", i8 0, !1}
+!1 = !{i64 0, !"typeid1"}
+!2 = !{!"alias1", i8 1, !1}
+; alias2 not included here, this could happen if the only reference to alias2
+; is in a module compiled without cfi-icall
+!3 = !{!"alias3", i8 1, !1}
+!4 = !{!"alias1", !"f", i8 0, i8 1}
+!5 = !{!"alias2", !"f", i8 1, i8 0}
+!6 = !{!"alias3", !"not_present", i8 0, i8 0}
Index: test/Transforms/LowerTypeTests/import-alias.ll
===================================================================
--- /dev/null
+++ test/Transforms/LowerTypeTests/import-alias.ll
@@ -0,0 +1,30 @@
+; RUN: opt -S %s -lowertypetests -lowertypetests-summary-action=import -lowertypetests-read-summary=%S/Inputs/import-alias.yaml | FileCheck %s
+;
+; Check that the definitions for @f and @f_alias are removed from this module
+; but @g_alias remains.
+;
+; CHECK: @g_alias = alias void (), void ()* @g
+; CHECK: define hidden void @f.cfi
+; CHECK: declare void @f()
+; CHECK: declare void @f_alias()
+
+target triple = "x86_64-unknown-linux"
+
+@f_alias = alias void (), void ()* @f
+@g_alias = alias void (), void ()* @g
+
+; Definition moved to the merged module
+define void @f() {
+  ret void
+}
+
+; Definition not moved to the merged module
+define void @g() {
+  ret void
+}
+
+define void @uses_aliases() {
+  call void @f_alias()
+  call void @g_alias()
+  ret void
+}