2015-01-01 09:32:14 +00:00
|
|
|
-- Copyright 2012-2015 Free Software Foundation, Inc.
|
[Ada] Handle reference to array descriptors
This patch is to help handle aliased array variables, such as:
type Bounded is array (Integer range <>) of Integer;
function New_Bounded (Low, High : Integer) return Bounded;
BT : aliased Bounded := New_Bounded (Low => 1, High => 3);
In that case, the compiler describes variable "BT" as a reference
to a thin pointer, and GDB is unable to print its value:
(gdb) p bt
$1 =
The problems starts when ada_value_print deconstructs the struct
value into contents and address in order to call val_print. It
turns out in this case that "bt" is not an lval. In the debug
information, this variable's location is described as:
.uleb128 0xd # (DIE (0xe0) DW_TAG_variable)
.ascii "bt\0" # DW_AT_name
[...]
.byte 0x6 # DW_AT_location
.byte 0x91 # DW_OP_fbreg
.sleb128 -56
.byte 0x6 # DW_OP_deref
.byte 0x23 # DW_OP_plus_uconst
.uleb128 0x8
.byte 0x9f # DW_OP_stack_value
So, when ada_value_print passes the bt's (value) address, it passes
in effect a meaningless address. The problem continues shortly after
when ada_val_print_1 re-creates the value from the contents and address.
The value has become an lval_memory, with a null address.
As a result, we trigger a memory error later on, while trying to
read the array bounds in order to transform our value into a simple
array.
To avoid the problem entirely, the fix is to coerce references before
transforming array descriptors into simple arrays.
gdb/ChangeLog:
* ada-valprint.c (ada_val_print_1): If our value is a reference
to an array descriptor, dereference it before converting it
to a simple array.
gdb/testsuite/ChangeLog:
* gdb.ada/aliased_array: New testcase.
2012-02-29 19:33:02 +00:00
|
|
|
--
|
|
|
|
|
-- 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/>.
|
|
|
|
|
|
|
|
|
|
package body Pck is
|
|
|
|
|
function New_Bounded (Low, High : Integer) return Bounded is
|
|
|
|
|
Result : Bounded (Low .. High);
|
|
|
|
|
begin
|
|
|
|
|
for J in Low .. High loop
|
|
|
|
|
Result (J) := J;
|
|
|
|
|
end loop;
|
|
|
|
|
return Result;
|
|
|
|
|
end New_Bounded;
|
|
|
|
|
|
|
|
|
|
procedure Do_Nothing (A : System.Address) is
|
|
|
|
|
begin
|
|
|
|
|
null;
|
|
|
|
|
end Do_Nothing;
|
|
|
|
|
end Pck;
|
