[Ada] Document the '-U' option for gnatelim

2018-05-25  Sergey Rybin  <rybin@adacore.com>

gcc/ada/

	* doc/gnat_ugn/gnat_and_program_execution.rst: Add description of '-U'
	option for gnatelim.

From-SVN: r260735

gcc/ada/ChangeLog

+2018-05-25  Sergey Rybin  <rybin@adacore.com>
+
+	* doc/gnat_ugn/gnat_and_program_execution.rst: Add description of '-U'
+	option for gnatelim.
+
 2018-05-25  Ed Schonberg  <schonberg@adacore.com>
 
 	* sem_ch6.adb (Analyze_Subprogram_Body_Helper): Do not create

gcc/ada/doc/gnat_ugn/gnat_and_program_execution.rst

@@ -2700,7 +2700,7 @@ appropriate options.
   ``gnatelim`` is a project-aware tool.
   (See :ref:`Using_Project_Files_with_GNAT_Tools` for a description of
   the project-related switches but note that ``gnatelim`` does not support
-  the :samp:`-U`, :samp:`-U {main_unit}`, :samp:`--subdirs={dir}`, or
+  the :samp:`-U {main_unit}`, :samp:`--subdirs={dir}`, or
   :samp:`--no_objects_dir` switches.)
   The project file package that can specify
   ``gnatelim`` switches is named ``Eliminate``.
@@ -2730,6 +2730,10 @@ appropriate options.
   treats these files as a complete set of sources making up a program to
   analyse, and analyses only these sources.
 
+  If ``gnatelim`` is called with a project file and :samp:`-U` option is
+  used, then in process all the files from the argument project but
+  not just the closure of the main subprogram.
+
   After a full successful build of the main subprogram ``gnatelim`` can be
   called without  specifying sources to analyse, in this case it computes
   the source closure of the main unit from the :file:`ALI` files.
@@ -2814,6 +2818,15 @@ appropriate options.
     equivalent ``gnatmake`` flag (:ref:`Switches_for_gnatmake`).
 
 
+  .. index:: -U (gnatelim)
+
+  :samp:`-U`
+    Process all the sources from the argument project. If no project file
+    is specified, this option has no effect. If this option is used with the
+    project file, ``gnatelim`` does not require the preliminary build of the
+    argument main subprogram.
+
+
   .. index:: -files (gnatelim)
 
   :samp:`-files={filename}`
@@ -2924,6 +2937,12 @@ appropriate options.
   your program from scratch after that, because you need a consistent
   configuration file(s) during the entire compilation.
 
+  If ``gnatelim`` is called with a project file and with ``-U`` option
+  the generated set of pragmas may contain pragmas for subprograms that
+  does not belong to the closure of the argument main subprogram. These
+  pragmas has no effect when the set of pragmas is used to reduce the size
+  of executable.
+
 
   .. _Making_Your_Executables_Smaller: