diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -152,8 +152,12 @@
 set(EXEEXT ${CMAKE_EXECUTABLE_SUFFIX})
 set(LTDL_SHLIB_EXT ${CMAKE_SHARED_LIBRARY_SUFFIX})
 
-# We use *.dylib rather than *.so on darwin.
-set(LLVM_PLUGIN_EXT ${CMAKE_SHARED_LIBRARY_SUFFIX})
+# We use *.dylib rather than *.so on darwin, but we stick with *.so on AIX.
+if(${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+  set(LLVM_PLUGIN_EXT ${CMAKE_SHARED_MODULE_SUFFIX})
+else()
+  set(LLVM_PLUGIN_EXT ${CMAKE_SHARED_LIBRARY_SUFFIX})
+endif()
 
 if(APPLE)
   if(LLVM_ENABLE_LLD AND LLVM_ENABLE_LTO)
diff --git a/llvm/include/llvm/Config/config.h.cmake b/llvm/include/llvm/Config/config.h.cmake
--- a/llvm/include/llvm/Config/config.h.cmake
+++ b/llvm/include/llvm/Config/config.h.cmake
@@ -317,6 +317,9 @@
 /* Define to the extension used for shared libraries, say, ".so". */
 #cmakedefine LTDL_SHLIB_EXT "${LTDL_SHLIB_EXT}"
 
+/* Define to the extension used for plugin libraries, say, ".so". */
+#cmakedefine LLVM_PLUGIN_EXT "${LLVM_PLUGIN_EXT}"
+
 /* Define to the address where bug reports for this package should be sent. */
 #cmakedefine PACKAGE_BUGREPORT "${PACKAGE_BUGREPORT}"
 
diff --git a/llvm/unittests/Support/DynamicLibrary/CMakeLists.txt b/llvm/unittests/Support/DynamicLibrary/CMakeLists.txt
--- a/llvm/unittests/Support/DynamicLibrary/CMakeLists.txt
+++ b/llvm/unittests/Support/DynamicLibrary/CMakeLists.txt
@@ -22,7 +22,7 @@
 export_executable_symbols(DynamicLibraryTests)
 
 function(dynlib_add_module NAME)
-  add_library(${NAME} SHARED
+  add_library(${NAME} MODULE
     PipSqueak.cpp
     )
   set_target_properties(${NAME} PROPERTIES FOLDER "Tests")
@@ -34,7 +34,7 @@
 
   set_target_properties(${NAME}
     PROPERTIES PREFIX ""
-    SUFFIX ${LTDL_SHLIB_EXT}
+    SUFFIX ${LLVM_PLUGIN_EXT}
     )
 
   add_dependencies(DynamicLibraryTests ${NAME})
@@ -54,8 +54,8 @@
 # Revert -Wl,-z,nodelete on this test since it relies on the file
 # being unloaded.
 if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
-  string(REPLACE "-Wl,-z,nodelete" "" CMAKE_SHARED_LINKER_FLAGS
-    ${CMAKE_SHARED_LINKER_FLAGS})
+  string(REPLACE "-Wl,-z,nodelete" "" CMAKE_MODULE_LINKER_FLAGS
+    ${CMAKE_MODULE_LINKER_FLAGS})
 endif()
 
 dynlib_add_module(PipSqueak)
diff --git a/llvm/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp b/llvm/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp
--- a/llvm/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp
+++ b/llvm/unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp
@@ -26,7 +26,7 @@
   void *Ptr = (void*)(intptr_t)TestA;
   std::string Path = fs::getMainExecutable(Argv0, Ptr);
   llvm::SmallString<256> Buf(path::parent_path(Path));
-  path::append(Buf, (Name + LTDL_SHLIB_EXT).c_str());
+  path::append(Buf, (Name + LLVM_PLUGIN_EXT).c_str());
   return std::string(Buf.str());
 }