Index: cmake/modules/AddLLVM.cmake
===================================================================
--- cmake/modules/AddLLVM.cmake
+++ cmake/modules/AddLLVM.cmake
@@ -395,6 +395,16 @@
   elseif(ARG_SHARED)
     add_windows_version_resource_file(ALL_FILES ${ALL_FILES})
     add_library(${name} SHARED ${ALL_FILES})
+    if(UNIX)
+      # Disable CMake's builtin SO versioning. Historically LLVM hasn't used so
+      # versioning on Darwin, and linux so versioning is hand-rolled.
+      set_target_properties(${name} PROPERTIES NO_SONAME On)
+      if(NOT APPLE)
+        set(library_name ${name}.${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR})
+        set_target_properties(${name} PROPERTIES OUTPUT_NAME ${library_name})
+        llvm_install_library_symlink(${name} ${library_name} SHARED ALWAYS_GENERATE)
+      endif()
+    endif()
   else()
     add_library(${name} STATIC ${ALL_FILES})
   endif()
@@ -433,7 +443,6 @@
 
     set_target_properties(${name}
       PROPERTIES
-      SOVERSION ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}
       VERSION ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}${LLVM_VERSION_SUFFIX})
   endif()
 
@@ -1029,6 +1038,38 @@
   endif()
 endfunction()
 
+function(llvm_install_library_symlink name dest type)
+  cmake_parse_arguments(ARG "ALWAYS_GENERATE" "" "" ${ARGN})
+  foreach(path ${CMAKE_MODULE_PATH})
+    if(EXISTS ${path}/LLVMInstallSymlink.cmake)
+      set(INSTALL_SYMLINK ${path}/LLVMInstallSymlink.cmake)
+      break()
+    endif()
+  endforeach()
+  
+  set(component ${name})
+
+  set(full_name ${CMAKE_${type}_LIBRARY_PREFIX}${name}${CMAKE_${type}_LIBRARY_SUFFIX})
+  set(full_dest ${CMAKE_${type}_LIBRARY_PREFIX}${dest}${CMAKE_${type}_LIBRARY_SUFFIX})
+
+  set(output_dir lib)
+  if(WIN32 AND "${type}" STREQUAL "SHARED")
+    set(output_dir bin)
+  endif()
+
+  install(SCRIPT ${INSTALL_SYMLINK}
+          CODE "install_symlink(${full_name} ${full_dest} ${output_dir})"
+          COMPONENT ${component})
+
+  if (NOT CMAKE_CONFIGURATION_TYPES AND NOT ARG_ALWAYS_GENERATE)
+    add_custom_target(install-${name}
+                      DEPENDS ${name} ${dest} install-${dest}
+                      COMMAND "${CMAKE_COMMAND}"
+                              -DCMAKE_INSTALL_COMPONENT=${name}
+                              -P "${CMAKE_BINARY_DIR}/cmake_install.cmake")
+  endif()
+endfunction()
+
 function(llvm_install_symlink name dest)
   cmake_parse_arguments(ARG "ALWAYS_GENERATE" "" "" ${ARGN})
   foreach(path ${CMAKE_MODULE_PATH})