diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -619,11 +619,22 @@
                                      "for the member defining symbol " +
                                      toMachOString(sym)));
 
-  auto file = make<ObjFile>(mb, modTime, getName());
-
-  symbols.insert(symbols.end(), file->symbols.begin(), file->symbols.end());
-  subsections.insert(subsections.end(), file->subsections.begin(),
-                     file->subsections.end());
+  InputFile *file;
+  switch (identify_magic(mb.getBuffer())) {
+  case file_magic::macho_object:
+    file = make<ObjFile>(mb, modTime, getName());
+    break;
+  case file_magic::bitcode:
+    file = make<BitcodeFile>(mb);
+    break;
+  default:
+    StringRef bufname =
+        CHECK(c.getName(), toString(this) + ": could not get buffer name");
+    error(toString(this) + ": archive member " + bufname +
+          " has unhandled file type");
+    return;
+  }
+  inputFiles.push_back(file);
 }
 
 BitcodeFile::BitcodeFile(MemoryBufferRef mbref)
diff --git a/lld/test/MachO/invalid/bad-archive-member.s b/lld/test/MachO/invalid/bad-archive-member.s
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/invalid/bad-archive-member.s
@@ -0,0 +1,20 @@
+# REQUIRES: x86
+# RUN: split-file %s %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/foo.s -o %t/foo.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/test.s -o %t/test.o
+# RUN: %lld -dylib -lSystem %t/foo.o -o %t/foo.dylib
+# RUN: rm -f %t/foo.a
+# RUN: llvm-ar rcs %t/foo.a %t/foo.dylib
+# RUN: not %lld %t/test.o %t/foo.a -o /dev/null 2>&1 | FileCheck %s -DFILE=%t/foo.a
+# CHECK: error: [[FILE]]: archive member foo.dylib has unhandled file type
+
+#--- foo.s
+.globl _foo
+_foo:
+  ret
+
+#--- test.s
+.globl _main
+_main:
+  callq _foo
+  ret
diff --git a/lld/test/MachO/lto-archive.ll b/lld/test/MachO/lto-archive.ll
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/lto-archive.ll
@@ -0,0 +1,28 @@
+; REQUIRES: x86
+; RUN: split-file %s %t
+; RUN: llvm-as %t/foo.ll -o %t/foo.o
+; RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/test.s -o %t/test.o
+; RUN: rm -f %t/foo.a
+; RUN: llvm-ar rcs %t/foo.a %t/foo.o
+; RUN: %lld -save-temps -lSystem %t/test.o %t/foo.a -o %t/test
+; RUN: llvm-objdump -d --macho --no-show-raw-insn %t/test | FileCheck %s
+
+; CHECK:      _main:
+; CHECK-NEXT: callq _foo
+; CHECK-NEXT: retq
+
+;--- foo.ll
+
+target triple = "x86_64-apple-macosx10.15.0"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @foo() {
+  ret void
+}
+
+;--- test.s
+
+.globl _main
+_main:
+  callq _foo
+  ret