forked from Imagelibrary/binutils-gdb
692252c4b0
In Ada, a field can have a dynamic bit offset in its enclosing record.
In DWARF 3, this was handled using a dynamic
DW_AT_data_member_location, combined with a DW_AT_bit_offset -- this
combination worked out ok because in practice GNAT only needs a
dynamic byte offset with a fixed offset within the byte.
However, this approach was deprecated in DWARF 4 and then removed in
DWARF 5. No replacement approach was given, meaning that in strict
mode there is no way to express this.
This is a DWARF bug, see
https://dwarfstd.org/issues/250501.1.html
In a discussion on the DWARF mailing list, a couple people mentioned
that compilers could use the obvious extension of a dynamic
DW_AT_data_bit_offset. I've implemented this for LLVM:
https://github.com/llvm/llvm-project/pull/141106
In preparation for that landing, this patch implements support for
this construct in gdb.
New in v2: renamed some constants and added a helper method, per
Simon's review.
New in v3: more renamings.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
96 lines
2.6 KiB
Plaintext
96 lines
2.6 KiB
Plaintext
# Copyright 2025 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/>.
|
|
|
|
# Test DW_AT_data_bit_offset with an expression. This is a DWARF
|
|
# extension, but expected to be in DWARF 6. See
|
|
# https://dwarfstd.org/issues/250501.1.html
|
|
|
|
load_lib dwarf.exp
|
|
|
|
# This test can only be run on targets which support DWARF-2 and use gas.
|
|
require dwarf2_support
|
|
|
|
standard_testfile ada-array-bound.c -debug.S
|
|
|
|
# Set up the DWARF for the test.
|
|
|
|
set asm_file [standard_output_file $srcfile2]
|
|
Dwarf::assemble $asm_file {
|
|
global srcdir subdir srcfile
|
|
|
|
cu {} {
|
|
DW_TAG_compile_unit {
|
|
{DW_AT_language @DW_LANG_Ada95}
|
|
{DW_AT_name $srcfile}
|
|
} {
|
|
declare_labels byte array struct
|
|
|
|
byte: DW_TAG_base_type {
|
|
{DW_AT_byte_size 1 DW_FORM_sdata}
|
|
{DW_AT_encoding @DW_ATE_unsigned}
|
|
{DW_AT_name byte}
|
|
}
|
|
|
|
array: DW_TAG_array_type {
|
|
{DW_AT_name array_type}
|
|
{DW_AT_type :$byte}
|
|
} {
|
|
DW_TAG_subrange_type {
|
|
{DW_AT_type :$byte}
|
|
{DW_AT_upper_bound 3 DW_FORM_sdata}
|
|
}
|
|
}
|
|
|
|
struct: DW_TAG_structure_type {
|
|
{DW_AT_name discriminated}
|
|
{DW_AT_byte_size 4 DW_FORM_sdata}
|
|
} {
|
|
DW_TAG_member {
|
|
{DW_AT_name disc}
|
|
{DW_AT_type :$byte}
|
|
{DW_AT_data_member_location 0 DW_FORM_sdata}
|
|
}
|
|
|
|
# We know this is always at offset 1 but use an
|
|
# expression just to test this code path. This is a
|
|
# DWARF extension. See
|
|
# https://dwarfstd.org/issues/250501.1.html.
|
|
DW_TAG_member {
|
|
{DW_AT_name nums}
|
|
{DW_AT_type :$array}
|
|
{DW_AT_data_bit_offset {DW_OP_lit8} SPECIAL_expr}
|
|
}
|
|
}
|
|
|
|
DW_TAG_variable {
|
|
{DW_AT_name "value"}
|
|
{DW_AT_type :$struct}
|
|
{DW_AT_external 1 DW_FORM_flag}
|
|
{DW_AT_location {DW_OP_addr [gdb_target_symbol "our_data"]}
|
|
SPECIAL_expr}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if {[prepare_for_testing "failed to prepare" ${testfile} \
|
|
[list $srcfile $asm_file] {nodebug}]} {
|
|
return -1
|
|
}
|
|
|
|
gdb_test_no_output "set language ada"
|
|
gdb_test "print value" \
|
|
[string_to_regexp " = (disc => 3, nums => (7, 11, 13))"]
|