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When -fgnat-encodings=minimal, the compiler will avoid the special
GNAT-specific "encodings" format, and instead emit ordinary DWARF as
much as possible.
When emitting DWARF for thick pointers to arrays, the compiler emits
something like:
<1><11db>: Abbrev Number: 7 (DW_TAG_array_type)
<11dc> DW_AT_name : (indirect string, offset: 0x1bb8): string
<11e0> DW_AT_data_location: 2 byte block: 97 6
(DW_OP_push_object_address; DW_OP_deref)
<11e3> DW_AT_type : <0x1173>
<11e7> DW_AT_sibling : <0x1201>
<2><11eb>: Abbrev Number: 8 (DW_TAG_subrange_type)
<11ec> DW_AT_type : <0x1206>
<11f0> DW_AT_lower_bound : 6 byte block: 97 23 8 6 94 4
(DW_OP_push_object_address; DW_OP_plus_uconst: 8; DW_OP_deref;
DW_OP_deref_size: 4)
<11f7> DW_AT_upper_bound : 8 byte block: 97 23 8 6 23 4 94 4
(DW_OP_push_object_address; DW_OP_plus_uconst: 8; DW_OP_deref;
DW_OP_plus_uconst: 4; DW_OP_deref_size: 4)
If you read between the lines, the "array" is actually a structure
with two elements. One element is a pointer to the array data, and
the other structure describes the bounds of the array. However, the
compiler doesn't emit this explicitly, but instead hides it behind
these location expressions.
gdb can print such objects, but currently there is no way to construct
one. So, this patch adds some code to the DWARF reader to recognize
this construct, and then synthesize an array descriptor. This
descriptor is then handled by the existing Ada code.
Internally, we've modified GCC to emit the structure type explicitly
(we will of course be sending this upstream). In this case, the array
still has the DW_AT_data_location, though. This patch also modifies
gdb to ignore the data location in this case -- this is preferred
because the location only serves to confuse the Ada code that already
knows where to find the data. In the future I hope to move some of
this handling to the gdb core, so that Ada-specific hacks are not
needed; however I have not yet done this.
Because parallel types are not emitted with -fgnat-encodings=minimal,
some changes to the Ada code were also required.
The change ina ada-valprint.c was needed to avoid infinite recursion
when trying to print a constrained packed array. And, there didn't
seem to be any need for a recursive call here -- the value could
simply be returned instead.
Finally, gdb.ada/frame_arg_lang.exp no longer works in C mode, because
we drop back to the structure approach now. As mentioned earlier,
future work should probably fix this again; meanwhile, this doesn't
seem to be a big problem, because it is what is currently done (users
as a rule don't use -fgnat-encodings=minimal -- which is what I am
ultimately trying to fix).
Note that a couple of tests have an added KFAIL. Some
-fgnat-encodings=minimal changes have landed in GNAT, and you need
something very recent to pass all the tests. I'm using git gcc to
accomplish this.
gdb/ChangeLog
2020-11-04 Tom Tromey <tromey@adacore.com>
* dwarf2/read.c (recognize_bound_expression)
(quirk_ada_thick_pointer): New functions.
(read_array_type): Call quirk_ada_thick_pointer.
(set_die_type): Add "skip_data_location" parameter.
(quirk_ada_thick_pointer): New function.
(process_structure_scope): Call quirk_ada_thick_pointer.
* ada-lang.c (ada_is_unconstrained_packed_array_type)
(decode_packed_array_bitsize): Handle thick pointers without
parallel types.
(ada_is_gnat_encoded_packed_array_type): Rename from
ada_is_packed_array_type.
(ada_is_constrained_packed_array_type): Update.
* ada-valprint.c (ada_val_print_gnat_array): Remove.
(ada_value_print_1): Use ada_get_decoded_value.
gdb/testsuite/ChangeLog
2020-11-04 Tom Tromey <tromey@adacore.com>
* gdb.ada/O2_float_param.exp: Test different -fgnat-encodings
values.
* gdb.ada/access_to_unbounded_array.exp: Test different
-fgnat-encodings values.
* gdb.ada/big_packed_array.exp: Test different -fgnat-encodings
values.
* gdb.ada/arr_enum_idx_w_gap.exp: Test different -fgnat-encodings
values.
* gdb.ada/array_ptr_renaming.exp: Test different -fgnat-encodings
values.
* gdb.ada/array_of_variable_length.exp: Test different
-fgnat-encodings values.
* gdb.ada/arrayparam.exp: Test different -fgnat-encodings values.
* gdb.ada/arrayptr.exp: Test different -fgnat-encodings values.
* gdb.ada/frame_arg_lang.exp: Revert -fgnat-encodings=minimal
change.
* gdb.ada/mi_string_access.exp: Test different -fgnat-encodings
values.
* gdb.ada/mod_from_name.exp: Test different -fgnat-encodings values.
* gdb.ada/out_of_line_in_inlined.exp: Test different
-fgnat-encodings values.
* gdb.ada/packed_array.exp: Test different -fgnat-encodings
values.
* gdb.ada/pckd_arr_ren.exp: Test different -fgnat-encodings
values.
* gdb.ada/unc_arr_ptr_in_var_rec.exp: Test different
-fgnat-encodings values.
* gdb.ada/variant_record_packed_array.exp: Test different
-fgnat-encodings values.
87 lines
3.0 KiB
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87 lines
3.0 KiB
Plaintext
# Copyright 2018-2020 Free Software Foundation, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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load_lib "ada.exp"
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if { [skip_ada_tests] } { return -1 }
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standard_ada_testfile bla
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set cfile "foo"
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set csrcfile ${srcdir}/${subdir}/${testdir}/${cfile}.c
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set cobject [standard_output_file ${cfile}.o]
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gdb_compile "${csrcfile}" "${cobject}" object [list debug]
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# Note we don't test the "none" (no -fgnat-encodings option) scenario
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# here, because "all" and "minimal" cover the cases, and this way we
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# don't have to update the test when gnat changes its default.
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foreach_with_prefix scenario {all minimal} {
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set flags [list debug additional_flags=-largs \
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additional_flags=${cobject} \
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additional_flags=-margs \
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additional_flags=-fgnat-encodings=$scenario]
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if {[gdb_compile_ada "${srcfile}" "${binfile}" executable $flags] != ""} {
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return -1
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}
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clean_restart ${testfile}
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set bp_location [gdb_get_line_number "STOP" ${testdir}/foo.c]
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runto "foo.c:$bp_location"
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gdb_test_no_output "set print frame-arguments all"
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# Here is the scenario:
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# - Once stopped in a C function, with language_mode set to auto, print
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# backtrace, we should see the Ada frame arguments printed using Ada
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# syntax.
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# - Set language to C, then check that printing backtrace shows the Ada
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# frame arguments using C syntax.
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# - Set language back to auto, check language mode value, then print
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# backtrace, we should see Ada frame arguments printed using Ada C
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# syntax.
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gdb_test "show lang" \
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"The current source language is \"auto; currently c\"." \
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"show language when set to 'auto; c'"
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gdb_test "bt" \
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"#1 $hex in pck\\.call_me \\(s=\"test\"\\).*" \
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"backtrace with auto: c"
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gdb_test_no_output "set language c" \
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"Set current source language to \"manual; currently c\"."
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gdb_test "show lang" \
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"The current source language is \"c\"." \
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"show language when set to 'c'"
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gdb_test "bt" \
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"#1 $hex in pck\\.call_me \\(s={P_ARRAY = $hex, P_BOUNDS = $hex}\\).*" \
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"backtrace with language forced to 'c'"
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gdb_test_no_output "set language auto" \
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"Set current source language to \"auto; currently c\"."
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gdb_test "show lang" \
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"The current source language is \"auto; currently c\"." \
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"show language when set back to 'auto; c'"
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gdb_test "bt" \
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"#1 $hex in pck\\.call_me \\(s=\"test\"\\).*" \
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"backtrace with language back to 'auto; c'"
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}
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