[Ada] Unnesting: allow uplevel references to exceptions

2018-05-28  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* einfo.ads, einfo.adb: Exceptions can be uplevel references, and thus
	they can appear as components of activation records.
	* exp_unst.adb (Visit_Node): A reference to an exception may be an
	uplevel reference.

From-SVN: r260840

gcc/ada/ChangeLog

+2018-05-28  Ed Schonberg  <schonberg@adacore.com>
+
+	* einfo.ads, einfo.adb: Exceptions can be uplevel references, and thus
+	they can appear as components of activation records.
+	* exp_unst.adb (Visit_Node): A reference to an exception may be an
+	uplevel reference.
+
 2018-05-28  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* exp_ch4.adb (Expand_Composite_Equality): Compute whether the size

gcc/ada/einfo.adb

@@ -744,6 +744,7 @@ package body Einfo is
    begin
       pragma Assert (Ekind_In (Id, E_Constant,
                                    E_Discriminant,
+                                   E_Exception,
                                    E_In_Parameter,
                                    E_In_Out_Parameter,
                                    E_Loop_Parameter,
@@ -3958,6 +3959,7 @@ package body Einfo is
    begin
       pragma Assert (Ekind_In (Id, E_Constant,
                                    E_Discriminant,
+                                   E_Exception,
                                    E_In_Parameter,
                                    E_In_Out_Parameter,
                                    E_Loop_Parameter,

gcc/ada/einfo.ads

@@ -6106,6 +6106,7 @@ package Einfo is
    --    Renamed_Entity                      (Node18)
    --    Register_Exception_Call             (Node20)
    --    Interface_Name                      (Node21)
+   --    Activation_Record_Component         (Node31)
    --    Discard_Names                       (Flag88)
    --    Is_Raised                           (Flag224)
 

gcc/ada/exp_unst.adb

@@ -798,9 +798,10 @@ package body Exp_Unst is
                  and then Chars (Enclosing_Subprogram (Ent)) /= Name_uParent
                  and then
 
-                   --  Constants and variables are interesting
+                   --  Constants, variables and exceptions are potentially
+                   --  uplevel references to global declarations.
 
-                   (Ekind_In (Ent, E_Constant, E_Variable)
+                   (Ekind_In (Ent, E_Constant, E_Exception, E_Variable)
 
                      --  Formals are interesting, but not if being used as mere
                      --  names of parameters for name notation calls.