old-cross-binutils/gdb/testsuite/gdb.ada/aliased_array/foo.adb

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[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
-- Copyright 2012 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
BT : aliased Bounded := New_Bounded (Low => 1, High => 3);
begin
Do_Nothing (BT'Address); -- STOP
end Foo;