diff --git a/clang/docs/CMakeLists.txt b/clang/docs/CMakeLists.txt
index dee97cc..4e4cf43 100644
--- a/clang/docs/CMakeLists.txt
+++ b/clang/docs/CMakeLists.txt
@@ -1,13 +1,38 @@
 
 if (DOXYGEN_FOUND)
 if (LLVM_ENABLE_DOXYGEN)
-  set(abs_srcdir ${LLVM_MAIN_SRC_DIR})
+  set(abs_srcdir ${CMAKE_CURRENT_SOURCE_DIR})
   set(abs_builddir ${LLVM_BINARY_DIR})
 
   if (HAVE_DOT)
     set(DOT ${LLVM_PATH_DOT})
   endif()
 
+  if (DOXYGEN_EXTERNAL_SEARCH)
+    set(SEARCHENGINE "YES")
+    set(SERVER_BASED_SEARCH "YES")
+    set(EXTERNAL_SEARCH "YES")
+
+    set(EXTRA_SEARCH_MAPPINGS "")
+    foreach(NameAndValue ${DOXYGEN_SEARCH_MAPPINGS})
+      # Strip leading spaces
+      string(REGEX REPLACE "^[ ]+" "" NameAndValue ${NameAndValue})
+      # Find variable name
+      string(REGEX MATCH "^[^=]+" Name ${NameAndValue})
+      # Find the value
+      string(REPLACE "${Name}=" "" Value ${NameAndValue})
+      # Set the variable
+      if (NOT ${Name} EQUALS clang)
+	set(EXTRA_SEARCH_MAPPINGS "${EXTRA_SEARCH_MAPPINGS} ${LLVM_BINARY_DIR}/${NameAndValue}")
+      endif()
+    endforeach()
+  else()
+    set(SEARCHENGINE "NO")
+    set(SERVER_BASED_SEARCH "NO")
+    set(EXTERNAL_SEARCH "NO")
+    set(EXTRA_SEARCH_MAPPINGS "")
+  endif()
+
   configure_file(${CMAKE_CURRENT_SOURCE_DIR}/doxygen.cfg.in
     ${CMAKE_CURRENT_BINARY_DIR}/doxygen.cfg @ONLY)
   set(abs_srcdir)
diff --git a/clang/docs/Makefile b/clang/docs/Makefile
index 2608046..0723ac9 100644
--- a/clang/docs/Makefile
+++ b/clang/docs/Makefile
@@ -19,7 +19,11 @@
 	  -e 's/@abs_srcdir@/./g' \
 	  -e 's/@DOT@/dot/g' \
 	  -e 's/@PACKAGE_VERSION@/mainline/' \
-	  -e 's/@abs_builddir@/./g' > $@
+	  -e 's/@abs_builddir@/./g' \
+	  -e 's/@enable_searchengine@/NO/g' \
+          -e 's/@enable_server_based_search@/NO/g' \
+	  -e 's/@enable_external_search@/NO/g' \
+	  -e 's/@extra_search_mappings@/NO/g' > $@
 endif
 
 include $(CLANG_LEVEL)/Makefile
diff --git a/clang/docs/doxygen.cfg.in b/clang/docs/doxygen.cfg.in
index ed9ffcb..497d4bf 100644
--- a/clang/docs/doxygen.cfg.in
+++ b/clang/docs/doxygen.cfg.in
@@ -1227,4 +1227,10 @@
 # The SEARCHENGINE tag specifies whether or not a search engine should be 
 # used. If set to NO the values of all tags below this one will be ignored.
 
-SEARCHENGINE           = NO
+SEARCHENGINE           = @enable_server_based_search@
+
+EXTERNAL_SEARCH        = @enable_external_search@
+
+EXTERNAL_SEARCH_ID     = clang
+
+EXTRA_SEARCH_MAPPINGS  = @extra_search_mappings@