Index: clang/docs/JSONCompilationDatabase.rst
===================================================================
--- clang/docs/JSONCompilationDatabase.rst
+++ clang/docs/JSONCompilationDatabase.rst
@@ -57,6 +57,7 @@
 
     [
       { "directory": "/home/user/llvm/build",
+        "command_compiler_args_index": 17,
         "command": "/usr/bin/clang++ -Irelative -DSOMEDEF=\"With spaces, quotes and \\-es.\" -c -o file.o file.cc",
         "file": "file.cc" },
       ...
@@ -78,8 +79,10 @@
    Parameters use shell quoting and shell escaping of quotes, with '``"``'
    and '``\``' being the only special characters. Shell expansion is not
    supported.
+-  **command_compiler_args_index:** (Optional) The index within the 'command' string, at which the compiler arguments start.
 -  **arguments:** The compile command executed as list of strings.
    Either **arguments** or **command** is required.
+-  **arguments_compiler_args_index:** (Optional) The index within the 'arguments' list, at which the compiler arguments start.
 -  **output:** The name of the output created by this compilation step.
    This field is optional. It can be used to distinguish different processing
    modes of the same input file.