Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -366,6 +366,11 @@
 option (LLVM_BUILD_EXTERNAL_COMPILER_RT
   "Build compiler-rt as an external project." OFF)
 
+set(LLVM_DYLIB_SOVERSION "${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}" CACHE STRING
+  "Specify the SOVERSION for libLLVM (specify \"cmake-default\" to use the CMake default)")
+set(LLVM_DYLIB_VERSION "${PACKAGE_VERSION}" CACHE STRING
+  "Specify the VERSION for libLLVM (specify \"cmake-default\" to use the CMake default)")
+
 # You can configure which libraries from LLVM you want to include in the
 # shared library by setting LLVM_DYLIB_COMPONENTS to a semi-colon delimited
 # list of LLVM components. All component names handled by llvm-config are valid.
Index: cmake/modules/AddLLVM.cmake
===================================================================
--- cmake/modules/AddLLVM.cmake
+++ cmake/modules/AddLLVM.cmake
@@ -326,7 +326,7 @@
 function(llvm_add_library name)
   cmake_parse_arguments(ARG
     "MODULE;SHARED;STATIC;DISABLE_LLVM_LINK_LLVM_DYLIB"
-    "OUTPUT_NAME"
+    "OUTPUT_NAME;SOVERSION;VERSION"
     "ADDITIONAL_HEADERS;DEPENDS;LINK_COMPONENTS;LINK_LIBS;OBJLIBS"
     ${ARGN})
   list(APPEND LLVM_COMMON_DEPENDS ${ARG_DEPENDS})
@@ -431,10 +431,25 @@
         )
     endif()
 
-    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})
+    # Set SOVERSION iff it is unspecified in arguments;
+    # we take a value of "cmake-default" to mean don't
+    # set the property.
+    set(soversion ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR})
+    if(ARG_SOVERSION)
+      set(soversion ${ARG_SOVERSION})
+    endif()
+    if(NOT "${soversion}" STREQUAL "cmake-default")
+      set_target_properties(${name} PROPERTIES SOVERSION ${soversion})
+    endif()
+
+    # As above, but for VERSION.
+    set(version ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}${LLVM_VERSION_SUFFIX})
+    if(ARG_VERSION)
+      set(version ${ARG_VERSION})
+    endif()
+    if(NOT "${version}" STREQUAL "cmake-default")
+      set_target_properties(${name} PROPERTIES VERSION ${version})
+    endif()
   endif()
 
   if(ARG_MODULE OR ARG_SHARED)
Index: tools/llvm-shlib/CMakeLists.txt
===================================================================
--- tools/llvm-shlib/CMakeLists.txt
+++ tools/llvm-shlib/CMakeLists.txt
@@ -72,7 +72,11 @@
   add_custom_target(libLLVMExports DEPENDS ${LLVM_EXPORTED_SYMBOL_FILE})
 endif()
 
-add_llvm_library(LLVM SHARED DISABLE_LLVM_LINK_LLVM_DYLIB ${SOURCES})
+add_llvm_library(LLVM ${SOURCES}
+    SHARED
+    SOVERSION ${LLVM_DYLIB_SOVERSION}
+    VERSION ${LLVM_DYLIB_VERSION}
+    DISABLE_LLVM_LINK_LLVM_DYLIB)
 
 list(REMOVE_DUPLICATES LIB_NAMES)
 if("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux") # FIXME: It should be "GNU ld for elf"