Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -588,7 +588,7 @@
 # check its symbols. This is wasteful (the check was done when foo.so
 # was created) and can fail since it is not the dynamic linker and
 # doesn't know how to handle search paths correctly.
-if (UNIX AND NOT APPLE AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
+if (UNIX AND NOT APPLE AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "SunOS|AIX")
   set(CMAKE_EXE_LINKER_FLAGS
       "${CMAKE_EXE_LINKER_FLAGS} -Wl,-allow-shlib-undefined")
 endif()
Index: cmake/modules/AddLLVM.cmake
===================================================================
--- cmake/modules/AddLLVM.cmake
+++ cmake/modules/AddLLVM.cmake
@@ -85,6 +85,9 @@
     if (${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
       set_property(TARGET ${target_name} APPEND_STRING PROPERTY
                    LINK_FLAGS "  -Wl,-M,${CMAKE_CURRENT_BINARY_DIR}/${native_export_file}")
+    elseif (${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+      set_property(TARGET ${target_name} APPEND_STRING PROPERTY
+                   LINK_FLAGS "  -Wl,-bE:${CMAKE_CURRENT_BINARY_DIR}/${native_export_file}")
     else()
       set_property(TARGET ${target_name} APPEND_STRING PROPERTY
                    LINK_FLAGS "  -Wl,--version-script,${CMAKE_CURRENT_BINARY_DIR}/${native_export_file}")
@@ -156,7 +159,7 @@
 
     # Pass -O3 to the linker. This enabled different optimizations on different
     # linkers.
-    if(NOT (${CMAKE_SYSTEM_NAME} MATCHES "Darwin|SunOS" OR WIN32))
+    if(NOT (${CMAKE_SYSTEM_NAME} MATCHES "Darwin|SunOS|AIX" OR WIN32))
       set_property(TARGET ${target_name} APPEND_STRING PROPERTY
                    LINK_FLAGS " -Wl,-O3")
     endif()
@@ -177,6 +180,9 @@
       elseif(${CMAKE_SYSTEM_NAME} MATCHES "SunOS")
         set_property(TARGET ${target_name} APPEND_STRING PROPERTY
                      LINK_FLAGS " -Wl,-z -Wl,discard-unused=sections")
+      elseif(${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+        set_property(TARGET ${target_name} APPEND_STRING PROPERTY
+                     LINK_FLAGS " -Wl,-bgc")
       elseif(NOT WIN32 AND NOT LLVM_LINKER_IS_GOLD)
         # Object files are compiled with -ffunction-data-sections.
         # Versions of bfd ld < 2.23.1 have a bug in --gc-sections that breaks
Index: cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- cmake/modules/HandleLLVMOptions.cmake
+++ cmake/modules/HandleLLVMOptions.cmake
@@ -141,7 +141,8 @@
 # build might work on ELF but fail on MachO/COFF.
 if(NOT (${CMAKE_SYSTEM_NAME} MATCHES "Darwin" OR WIN32 OR CYGWIN OR
         ${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD" OR
-        ${CMAKE_SYSTEM_NAME} MATCHES "OpenBSD") AND
+        ${CMAKE_SYSTEM_NAME} MATCHES "OpenBSD" OR
+        ${CMAKE_SYSTEM_NAME} MATCHES "AIX") AND
    NOT LLVM_USE_SANITIZER)
   set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,-z,defs")
 endif()