Patchwork [Ada] Missing master for incomplete views

login
register
mail settings
Submitter Arnaud Charlet
Date July 8, 2013, 7:44 a.m.
Message ID <20130708074410.GA28681@adacore.com>
Download mbox | patch
Permalink /patch/257478/
State New
Headers show

Comments

Arnaud Charlet - July 8, 2013, 7:44 a.m.
This patch fixes a compiler bug that caused the master of incomplete views to
be missing, which caused a crash when allocating an object of the type, if the
full type contains tasks.

The following example must compile quietly:

gcc -c -gnat05 lim_view_example.adb lim_view_example-child.adb

limited with Lim_View_Example.Child;
package Lim_View_Example is
   type Acc is access Child.Child_T;
   procedure P (X : out Acc);
end Lim_View_Example;

package Lim_View_Example.Child is
   task type Task_Type;

   type Child_T is record
      A_Task : Task_Type;
   end record;
end Lim_View_Example.Child;

with Lim_View_Example.Child;
package body Lim_View_Example is
   procedure P (X : out Acc) is
   begin
      X := new Child.Child_T;
   end P;
end Lim_View_Example;

package body Lim_View_Example.Child is
   task body Task_Type is
   begin
      null;
   end Task_Type;
end Lim_View_Example.Child;

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

2013-07-08  Bob Duff  <duff@adacore.com>

	* exp_ch3.adb (Build_Master): If Desig_Type is an incomplete
	view coming from a limited-with'ed package, use the nonlimited
	view in case it has tasks.

Patch

Index: exp_ch3.adb
===================================================================
--- exp_ch3.adb	(revision 200709)
+++ exp_ch3.adb	(working copy)
@@ -4632,9 +4632,19 @@ 
       ------------------
 
       procedure Build_Master (Ptr_Typ : Entity_Id) is
-         Desig_Typ : constant Entity_Id := Designated_Type (Ptr_Typ);
+         Desig_Typ : Entity_Id := Designated_Type (Ptr_Typ);
 
       begin
+         --  If the designated type is an incomplete view coming from a
+         --  limited-with'ed package, we need to use the nonlimited view in
+         --  case it has tasks.
+
+         if Ekind (Desig_Typ) in Incomplete_Kind
+           and then Present (Non_Limited_View (Desig_Typ))
+         then
+            Desig_Typ := Non_Limited_View (Desig_Typ);
+         end if;
+
          --  Anonymous access types are created for the components of the
          --  record parameter for an entry declaration. No master is created
          --  for such a type.