[Ada] Do not query the representation information in CodePeer/GNATprove

Representation information generated when user calls the compiler with -gnatR
switch is not available when running the frontend inside CodePeer or GNATprove.
Do not query such information in that case, as this leads to spurious messages
that it is not available.

There is no impact on compilation.

2018-06-11  Yannick Moy  <moy@adacore.com>

gcc/ada/

	* gnat1drv.adb: Do not check representation information in CodePeer and
	GNATprove modes, as these modes call a special backend instead of gigi,
	so do not have the information.

From-SVN: r261414

gcc/ada/ChangeLog

 2018-06-11  Yannick Moy  <moy@adacore.com>
 
+	* gnat1drv.adb: Do not check representation information in CodePeer and
+	GNATprove modes, as these modes call a special backend instead of gigi,
+	so do not have the information.
+
+2018-06-11  Yannick Moy  <moy@adacore.com>
+
 	* inline.adb (Build_Body_To_Inline): Consider case of extended return
 	of unconstrained type as one case where inlining is not supported.
 	(Expand_Inlined_Call): Remove special case for body as extended return

gcc/ada/gnat1drv.adb

@@ -1455,6 +1455,9 @@ begin
       --  representation information will be provided by the GNSA back end, not
       --  gigi.
 
+      --  A special back end is always called in CodePeer and GNATprove modes,
+      --  unless this is a subunit.
+
       if Back_End_Mode = Declarations_Only
         and then
           (not (Back_Annotate_Rep_Info or Generate_SCIL or GNATprove_Mode)
@@ -1468,7 +1471,11 @@ begin
          Tree_Dump;
          Tree_Gen;
          Namet.Finalize;
-         Check_Rep_Info;
+
+         if not (Generate_SCIL or GNATprove_Mode) then
+            Check_Rep_Info;
+         end if;
+
          return;
       end if;