old-cross-binutils/gdb/testsuite/gdb.ada/arraydim/foo.adb
Joel Brobecker 8a48ac9579 wrong dimension found in ada-lang.c:ada_array_bound_from_type
This function has the following code:

  elt_type = type;
  for (i = n; i > 1; i--)
    elt_type = TYPE_TARGET_TYPE (type);

For multi-dimension arrays, the code above tries to find the array
type corresponding to the dimension we're trying to inspect.
The problem is that, past the second dimension, the loop does
nothing other than repeat the first iteration. There is a little
thinko where it got the TYPE_TARGET_TYPE of TYPE instead of ELT_TYPE!

To my surprise, I was unable to produce an Ada exemple that demonstrated
the problem.  That's because the examples I created all trigger a parallel
___XA type which we then use in place of the ELT_TYPE in order to
determine the bounds - see the code that immediately follows our
loop above:

    index_type_desc = ada_find_parallel_type (type, "___XA");
    ada_fixup_array_indexes_type (index_type_desc);
    if (index_type_desc != NULL)
    [...]

So, in order to avoid depending on an Ada example where the compiler
can potentially decide one way or the other, I decided to use an
artificial example, written in C. With ...

  int multi[1][2][3];

... forcing the language to Ada, and trying to print the 'last,
we get:

    (gdb) p multi'last(1)
    $1 = 0
    (gdb) p multi'last(2)
    $2 = 1
    (gdb) p multi'last(3)
    $3 = 1   <<<---  This should be 2!

Additionally, I noticed that a couple of check_typedef's were missing.
This patch adds them. And since the variable in question only gets
used within an "else" block, I moved the variable declaration and
use inside that block - making it clear what the scope of the variable
is.

gdb/ChangeLog:

        * ada-lang.c (ada_array_bound_from_type): Move the declaration
        and assignment of variable "elt_type" inside the else block
        where it is used.  Add two missing check_typedef calls.
        Fix bug where we got TYPE's TYPE_TARGET_TYPE, where in fact
        we really wanted to get ELT_TYPE's TYPE_TARGET_TYPE.

gdb/testsuite/ChangeLog:

        * gdb.ada/arraydim: New testcase.
2013-12-13 09:55:24 +01:00

30 lines
1.2 KiB
Ada

-- Copyright 2013 Free Software Foundation, Inc.
--
-- This program is free software; you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation; either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
with Pck; use Pck;
procedure Foo is
type Multi is array (1 .. 1, 2 .. 3, 4 .. 6) of Integer;
M : Multi := (others => (others => (others => 0)));
-- Use a fake type for importing our C multi-dimensional array.
-- It's only to make sure the C unit gets linked in, regardless
-- of possible optimizations.
type Void_Star is access integer;
E : Void_Star;
pragma Import (C, E, "global_3dim_for_gdb_testing");
begin
Do_Nothing (M'Address); -- STOP
Do_Nothing (E'Address);
end Foo;