[Ada] Strip too long expressions in debug routines

2018-05-25  Arnaud Charlet  <charlet@adacore.com>

gcc/ada/

	* pprint.adb (Expression_Name): Strip too long expressions to avoid
	carrying very large strings.

From-SVN: r260732

gcc/ada/ChangeLog

+2018-05-25  Arnaud Charlet  <charlet@adacore.com>
+
+	* pprint.adb (Expression_Name): Strip too long expressions to avoid
+	carrying very large strings.
+
 2018-05-25  Patrick Bernardi  <bernardi@adacore.com>
 
 	* switch-b.adb (Scan_Binder_Switches): binder switch -Q accepts Natural

gcc/ada/pprint.adb

@@ -883,6 +883,7 @@ package body Pprint is
          end if;
 
          declare
+            Threshold        : constant := 256;
             Buffer           : String (1 .. Natural (End_Sloc - Scn));
             Index            : Natural := 0;
             Skipping_Comment : Boolean := False;
@@ -935,6 +936,12 @@ package body Pprint is
                         end if;
                   end case;
 
+                  --  Give up on too long strings
+
+                  if Index >= Threshold then
+                     return Buffer (1 .. Index) & "...";
+                  end if;
+
                   Scn := Scn + 1;
                end loop;
             end if;