This patch removes a spurious initialization on the string that builds the
name of task that is a record component, when Initialize_Scalars is enabled.
This is both efficient, and prevents anomalies in the handling of dynamic
objects on the secondary stack, that would result in a mangled name for such
a task.
The following commands:
gnatmake -q -O1 p.adb
p
must yield:
where.container.a_tt_0000000100800E00
---
with Alloc;
procedure P is
begin
Alloc.Alloc_One (1);
end;
---
package Alloc is
procedure Alloc_One (Index : Integer);
end;
---
with CC; use CC;
package body Alloc is
type Container_Pointer is access all Container;
type Container_With_Ref_Count_Type is record
Container : Container_Pointer;
Ref_Count : Natural;
end record;
Containers : array (1 .. 3) of Container_With_Ref_Count_Type
:= (others => (null, 0));
procedure Alloc_One (Index : Integer) is
Where : Container_With_Ref_Count_Type renames Containers (Index);
begin
Where.Container := new Container;
end;
end;
---
with Ada.Task_Identification; use Ada.Task_Identification;
with Ada.Text_IO; use Ada.Text_IO;
package body CC is
task body TT is
begin
Put_Line (Image (Current_Task));
delay 1.0;
end;
end;
---
package CC is
type Container;
task type TT (C : not null access Container);
type Container is limited record
A_TT : TT (Container'Access);
end record;
end;
---
pragma Initialize_Scalars;
---
Tested on x86_64-pc-linux-gnu, committed on trunk
2014-01-29 Ed Schonberg <[email protected]>
* exp_util.adb (Build_Task_Image_Prefix): Indicate that the
resulting string is an internal entity. and thus requires no
initialization. This is relevant when Initialize_ Scalars is
enabled, because the resultant spurious initialization may lead to
secondary stack anomalies that produce a mangled name for a task.
Index: exp_util.adb
===================================================================
--- exp_util.adb (revision 207241)
+++ exp_util.adb (working copy)
@@ -1403,6 +1403,12 @@
Low_Bound => Make_Integer_Literal (Loc, 1),
High_Bound => New_Occurrence_Of (Len, Loc)))))));
+ -- Indicate that the result is an internal temporary, so it does not
+ -- receive a bogus initialization when declaration is expanded. This
+ -- is both efficient, and prevents anomalies in the handling of
+ -- dynamic objects on the secondary stack.
+
+ Set_Is_Internal (Res);
Pos := Make_Temporary (Loc, 'P');
Append_To (Decls,
