[Ada] Prohibit concurrent types in Ghost regions

This patch ensures that single concurrent type declarations are marked as Ghost
when they appear within a Ghost region. In addition, the patch verifies that no
concurrent type is declared within a Ghost region and issues an error.

------------
-- Source --
------------

--  types.ads

package Types with Ghost is
   protected Prot_Obj is                                             --  Error
   end Prot_Obj;

   protected type Prot_Typ is                                        --  Error
   end Prot_Typ;

   task Task_Obj;                                                    --  Error

   task type Task_Typ;                                               --  Error
end Types;

----------------------------
-- Compilation and output --
----------------------------

$ gcc -c types.ads
types.ads:2:14: ghost type "Prot_Obj" cannot be concurrent
types.ads:5:19: ghost type "Prot_Typ" cannot be concurrent
types.ads:8:09: ghost type "Task_Obj" cannot be concurrent
types.ads:10:14: ghost type "Task_Typ" cannot be concurrent

2018-01-11  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* freeze.adb (Freeze_Entity): Ensure that a Ghost type is not
	concurrent, nor effectively volatile.
	* ghost.adb (Check_Ghost_Type): New routine.
	* ghost.ads (Check_Ghost_Type): New routine.
	* sem_util.adb (Is_Declaration): Reimplemented. The routine can now
	consider specific subsets of declarations.
	(Is_Declaration_Other_Than_Renaming): Removed. Its functionality is
	replicated by Is_Declaration.
	* sem_util.ads (Is_Declaration): New parameter profile. Update the
	comment on usage.
	(Is_Declaration_Other_Than_Renaming): Removed.

From-SVN: r256521

1 files changed, 36 insertions, 0 deletions

diff --git a/gcc/ada/ghost.adb b/gcc/ada/ghost.adb
index 6dad9c2..5997724 100644
--- a/gcc/ada/ghost.adb
+++ b/gcc/ada/ghost.adb
@@ -806,6 +806,42 @@ package body Ghost is
       end if;
    end Check_Ghost_Refinement;
 
+   ----------------------
+   -- Check_Ghost_Type --
+   ----------------------
+
+   procedure Check_Ghost_Type (Typ : Entity_Id) is
+      Conc_Typ : Entity_Id;
+      Full_Typ : Entity_Id;
+
+   begin
+      if Is_Ghost_Entity (Typ) then
+         Conc_Typ := Empty;
+         Full_Typ := Typ;
+
+         if Is_Single_Concurrent_Type (Typ) then
+            Conc_Typ := Anonymous_Object (Typ);
+            Full_Typ := Conc_Typ;
+
+         elsif Is_Concurrent_Type (Typ) then
+            Conc_Typ := Typ;
+         end if;
+
+         --  A Ghost type cannot be concurrent (SPARK RM 6.9(19)). Verify this
+         --  legality rule first to give a finer-grained diagnostic.
+
+         if Present (Conc_Typ) then
+            Error_Msg_N ("ghost type & cannot be concurrent", Conc_Typ);
+         end if;
+
+         --  A Ghost type cannot be effectively volatile (SPARK RM 6.9(7))
+
+         if Is_Effectively_Volatile (Full_Typ) then
+            Error_Msg_N ("ghost type & cannot be volatile", Full_Typ);
+         end if;
+      end if;
+   end Check_Ghost_Type;
+
    ------------------
    -- Ghost_Entity --
    ------------------