[Ada] Implement AI12-0398-1/03

[Pierre-Marie de Rodat]

This commit implements AI12-0398-1/03, which adds the ability to specify
aspects on discriminant specifications, extended return object
declarations and entry index specifications.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * par-ch3.adb (P_Discriminant_Part_Opt): Parse aspects, update
        documentation.
        * par-ch6.adb (P_Return_Statement): Likewise.
        * par-ch9.adb (P_Entry_Index_Specification): Likewise.
diff --git a/gcc/ada/par-ch3.adb b/gcc/ada/par-ch3.adb
--- a/gcc/ada/par-ch3.adb
+++ b/gcc/ada/par-ch3.adb
@@ -3002,9 +3002,9 @@ package body Ch3 is
 
    --  DISCRIMINANT_SPECIFICATION ::=
    --    DEFINING_IDENTIFIER_LIST : [NULL_EXCLUSION] SUBTYPE_MARK
-   --      [:= DEFAULT_EXPRESSION]
+   --      [:= DEFAULT_EXPRESSION] [ASPECT_SPECIFICATION]
    --  | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
-   --      [:= DEFAULT_EXPRESSION]
+   --      [:= DEFAULT_EXPRESSION] [ASPECT_SPECIFICATION]
 
    --  If no known discriminant part is present, then No_List is returned
 
@@ -3098,6 +3098,10 @@ package body Ch3 is
                Set_Expression
                  (Specification_Node, Init_Expr_Opt (True));
 
+               if Token = Tok_With then
+                  P_Aspect_Specifications (Specification_Node, False);
+               end if;
+
                if Ident > 1 then
                   Set_Prev_Ids (Specification_Node, True);
                end if;


diff --git a/gcc/ada/par-ch6.adb b/gcc/ada/par-ch6.adb
--- a/gcc/ada/par-ch6.adb
+++ b/gcc/ada/par-ch6.adb
@@ -1770,7 +1770,8 @@ package body Ch6 is
    --
    --  EXTENDED_RETURN_STATEMENT ::=
    --    return DEFINING_IDENTIFIER : [aliased] RETURN_SUBTYPE_INDICATION
-   --                                           [:= EXPRESSION] [do
+   --                                           [:= EXPRESSION]
+   --                                           [ASPECT_SPECIFICATION] [do
    --      HANDLED_SEQUENCE_OF_STATEMENTS
    --    end return];
    --
@@ -1916,6 +1917,7 @@ package body Ch6 is
       Ret_Sloc : constant Source_Ptr := Token_Ptr;
       Ret_Strt : constant Column_Number := Start_Column;
       Ret_Node : Node_Id;
+      Decl     : Node_Id;
 
    --  Start of processing for P_Return_Statement
 
@@ -1955,8 +1957,12 @@ package body Ch6 is
             end if;
 
             Ret_Node := New_Node (N_Extended_Return_Statement, Ret_Sloc);
-            Set_Return_Object_Declarations
-              (Ret_Node, New_List (P_Return_Object_Declaration));
+            Decl := P_Return_Object_Declaration;
+            Set_Return_Object_Declarations (Ret_Node, New_List (Decl));
+
+            if Token = Tok_With then
+               P_Aspect_Specifications (Decl, False);
+            end if;
 
             if Token = Tok_Do then
                Push_Scope_Stack;


diff --git a/gcc/ada/par-ch9.adb b/gcc/ada/par-ch9.adb
--- a/gcc/ada/par-ch9.adb
+++ b/gcc/ada/par-ch9.adb
@@ -1316,6 +1316,7 @@ package body Ch9 is
 
    --  ENTRY_INDEX_SPECIFICATION ::=
    --    for DEFINING_IDENTIFIER in DISCRETE_SUBTYPE_DEFINITION
+   --                                                    [ASPECT_SPECIFICATION]
 
    --  Error recovery: can raise Error_Resync
 
@@ -1329,6 +1330,11 @@ package body Ch9 is
       T_In;
       Set_Discrete_Subtype_Definition
         (Iterator_Node, P_Discrete_Subtype_Definition);
+
+      if Token = Tok_With then
+         P_Aspect_Specifications (Iterator_Node, False);
+      end if;
+
       return Iterator_Node;
    end P_Entry_Index_Specification;