This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug ada/42140] New: GNAT appears to misbehave with limited tagged types and possibly finalization
- From: "gcc at coreland dot ath dot cx" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 22 Nov 2009 05:22:10 -0000
- Subject: [Bug ada/42140] New: GNAT appears to misbehave with limited tagged types and possibly finalization
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
I'm working on a small project to create an abstraction over directories
and archives. I've managed to write some code that seems simple enough
(using tagged limited types) and even though the code appears to be valid,
it seems to either trigger bugs in the runtime (causing crashes on execution)
or fails to compile:
Both Debian GCC 4.3, GNAT GPL 2009 and FreeBSD GCC 4.4 fail with the following:
pfseudo-archiver-directory.adb:24:41: wrong type for
return_subtype_indication
pfseudo-archiver-directory.adb:46:35: wrong type for
return_subtype_indication
GCC SVN (r154285) fails to build with a strange error:
arc_dir_003.adb:25:32: "_master" conflicts with declaration at line 21
The output of -gnatG shows this error to be apparently incorrect:
error := false;
B_1 : declare
_master : constant integer := system__soft_links__current_master.all;
A6bM : integer renames _master;
type A6b is access all pfseudo__archiver__Tarchive_tC;
R7b : A6b := pfseudo__archiver__directory.
The code is available here:
http://git.coreland.ath.cx/gitweb.cgi?p=pfseudo/.git;a=summary
$ git clone http://git.coreland.ath.cx/pfseudo/.git
Configure and build with:
$ echo 'gcc' > conf-adacomp
$ echo 'gnatbind' > conf-adabind
$ echo 'gnatlink' > conf-adalink
$ make
$ make tests
Here's another case from a prototype that causes a crash on GCC 4.4
but, ironically, gives every impression of compiling and running
on earlier versions (4.3, GPL 2009):
with Ada.Streams.Stream_IO;
with Ada.Finalization;
package Archiver is
type Archiver_t is tagged limited private;
type Archive_t is tagged limited private;
function Open_Archive
(Archiver : in Archiver_t;
Path : in String) return Archive_t'Class;
function Stream
(Archive : in Archive_t)
return Ada.Streams.Stream_IO.Stream_Access;
private
package Stream_IO renames Ada.Streams.Stream_IO;
type Archiver_t is tagged limited null record;
type Archive_t is new Ada.Finalization.Limited_Controlled with record
Name : access String;
File : Stream_IO.File_Type;
end record;
end Archiver;
package body Archiver is
function Open_Archive
(Archiver : in Archiver_t;
Path : in String) return Archive_t'Class
is
pragma Unreferenced (Archiver);
begin
-- This line causes a segmentation fault.
return A : Archive_t'Class :=
Archive_t'(Ada.Finalization.Limited_Controlled with others => <>) do
A.Name := new String'(Path);
Stream_IO.Open
(Name => A.Name.all,
File => A.File,
Mode => Stream_IO.In_File);
end return;
end Open_Archive;
function Stream
(Archive : in Archive_t)
return Ada.Streams.Stream_IO.Stream_Access is
begin
return Stream_IO.Stream (Archive.File);
end Stream;
end Archiver;
with Ada.Text_IO;
with Ada.Streams.Stream_IO;
with Archiver;
procedure Main is
A : Archiver.Archiver_t;
S : constant Ada.Streams.Stream_IO.Stream_Access := Archiver.Stream
(Archiver.Open_Archive (A, "file.zip"));
X : Integer;
begin
X := Integer'Input (S);
Ada.Text_IO.Put_Line (Integer'Image (X));
end Main;
--
Summary: GNAT appears to misbehave with limited tagged types and
possibly finalization
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ada
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: gcc at coreland dot ath dot cx
GCC host triplet: x86_64-portbld-freebsd7.2, i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42140