A user pointed out a problem when printing certain values from an Ada
enumeration type. Investigation showed that the problem was that some
enumeration constants were emitted using DW_FORM_data1, and were
incorrectly sign-extended by gdb.
First, this is yet another instance of a general problem with DWARF.
See https://sourceware.org/bugzilla/show_bug.cgi?id=32680 for the
analysis.
Meanwhile, it turns out that GCC implements an extension to handle
this scenario. In particular, in non-strict mode, it will emit
DW_AT_encoding using either DW_ATE_signed or DW_ATE_unsigned. This
was done back in 2017 by Pierre-Marie, in support of Ada -- but then
somehow nothing was ever implemented on the gdb side. For this see
GCC commit
f76f096e ("DWARF: add DW_AT_encoding attributes for
DW_TAG_enumeration_type DIEs").
This patch adds the missing code to gdb. The included test case shows
the bug that was originally reported. I've also included the snippet
from Pierre-Marie's commit message for good measure.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32680
Approved-By: Andrew Burgess <aburgess@redhat.com>
set_type_align (type, TYPE_RAW_ALIGN (underlying_type));
}
+ /* DW_AT_encoding on an enumeration type is a GCC extension. GCC
+ will only emit DW_ATE_signed or DW_ATE_unsigned here. If this is
+ seen, it provides a way to find the signed-ness without having to
+ guess based on the constants, which is somewhat fraught anyway
+ (see PR symtab/32680). */
+ if (!is_unsigned.has_value ())
+ {
+ attribute *encoding_attr = dwarf2_attr (die, DW_AT_encoding, cu);
+ if (encoding_attr != nullptr)
+ {
+ std::optional<ULONGEST> val = encoding_attr->unsigned_constant ();
+ if (val.has_value ())
+ is_unsigned = *val == DW_ATE_unsigned;
+ }
+ }
+
type->set_is_declared_class (dwarf2_flag_true_p (die, DW_AT_enum_class, cu));
type->set_endianity_is_not_default (die_byte_order (die, cu, nullptr));
--- /dev/null
+# Copyright 2026 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/>.
+
+load_lib "ada.exp"
+
+require allow_ada_tests
+
+standard_ada_testfile prog
+
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable debug] != ""} {
+ return
+}
+
+clean_restart ${testfile}
+
+set bp_location [gdb_get_line_number "STOP" ${testdir}/prog.adb]
+runto "prog.adb:$bp_location"
+
+for {set num 0} {$num <= 300} {incr num} {
+ gdb_test "print Value_$num" " = value_$num"
+ gdb_test "print Unsigned_Enumeration'Val($num)" " = value_$num"
+ gdb_test "print/d Unsigned_Enumeration'Val($num)" " = $num"
+}
+
+foreach {name dec} {se_a -1 se_b 0 se_c 1 se_d 2} {
+ gdb_test "print $name" " = $name"
+ gdb_test "print/d $name" " = $dec"
+}
--- /dev/null
+-- Copyright 2026 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/>.
+
+procedure Prog is
+ type Unsigned_Enumeration is
+ (
+ Value_0,
+ Value_1,
+ Value_2,
+ Value_3,
+ Value_4,
+ Value_5,
+ Value_6,
+ Value_7,
+ Value_8,
+ Value_9,
+ Value_10,
+ Value_11,
+ Value_12,
+ Value_13,
+ Value_14,
+ Value_15,
+ Value_16,
+ Value_17,
+ Value_18,
+ Value_19,
+ Value_20,
+ Value_21,
+ Value_22,
+ Value_23,
+ Value_24,
+ Value_25,
+ Value_26,
+ Value_27,
+ Value_28,
+ Value_29,
+ Value_30,
+ Value_31,
+ Value_32,
+ Value_33,
+ Value_34,
+ Value_35,
+ Value_36,
+ Value_37,
+ Value_38,
+ Value_39,
+ Value_40,
+ Value_41,
+ Value_42,
+ Value_43,
+ Value_44,
+ Value_45,
+ Value_46,
+ Value_47,
+ Value_48,
+ Value_49,
+ Value_50,
+ Value_51,
+ Value_52,
+ Value_53,
+ Value_54,
+ Value_55,
+ Value_56,
+ Value_57,
+ Value_58,
+ Value_59,
+ Value_60,
+ Value_61,
+ Value_62,
+ Value_63,
+ Value_64,
+ Value_65,
+ Value_66,
+ Value_67,
+ Value_68,
+ Value_69,
+ Value_70,
+ Value_71,
+ Value_72,
+ Value_73,
+ Value_74,
+ Value_75,
+ Value_76,
+ Value_77,
+ Value_78,
+ Value_79,
+ Value_80,
+ Value_81,
+ Value_82,
+ Value_83,
+ Value_84,
+ Value_85,
+ Value_86,
+ Value_87,
+ Value_88,
+ Value_89,
+ Value_90,
+ Value_91,
+ Value_92,
+ Value_93,
+ Value_94,
+ Value_95,
+ Value_96,
+ Value_97,
+ Value_98,
+ Value_99,
+ Value_100,
+ Value_101,
+ Value_102,
+ Value_103,
+ Value_104,
+ Value_105,
+ Value_106,
+ Value_107,
+ Value_108,
+ Value_109,
+ Value_110,
+ Value_111,
+ Value_112,
+ Value_113,
+ Value_114,
+ Value_115,
+ Value_116,
+ Value_117,
+ Value_118,
+ Value_119,
+ Value_120,
+ Value_121,
+ Value_122,
+ Value_123,
+ Value_124,
+ Value_125,
+ Value_126,
+ Value_127,
+ Value_128,
+ Value_129,
+ Value_130,
+ Value_131,
+ Value_132,
+ Value_133,
+ Value_134,
+ Value_135,
+ Value_136,
+ Value_137,
+ Value_138,
+ Value_139,
+ Value_140,
+ Value_141,
+ Value_142,
+ Value_143,
+ Value_144,
+ Value_145,
+ Value_146,
+ Value_147,
+ Value_148,
+ Value_149,
+ Value_150,
+ Value_151,
+ Value_152,
+ Value_153,
+ Value_154,
+ Value_155,
+ Value_156,
+ Value_157,
+ Value_158,
+ Value_159,
+ Value_160,
+ Value_161,
+ Value_162,
+ Value_163,
+ Value_164,
+ Value_165,
+ Value_166,
+ Value_167,
+ Value_168,
+ Value_169,
+ Value_170,
+ Value_171,
+ Value_172,
+ Value_173,
+ Value_174,
+ Value_175,
+ Value_176,
+ Value_177,
+ Value_178,
+ Value_179,
+ Value_180,
+ Value_181,
+ Value_182,
+ Value_183,
+ Value_184,
+ Value_185,
+ Value_186,
+ Value_187,
+ Value_188,
+ Value_189,
+ Value_190,
+ Value_191,
+ Value_192,
+ Value_193,
+ Value_194,
+ Value_195,
+ Value_196,
+ Value_197,
+ Value_198,
+ Value_199,
+ Value_200,
+ Value_201,
+ Value_202,
+ Value_203,
+ Value_204,
+ Value_205,
+ Value_206,
+ Value_207,
+ Value_208,
+ Value_209,
+ Value_210,
+ Value_211,
+ Value_212,
+ Value_213,
+ Value_214,
+ Value_215,
+ Value_216,
+ Value_217,
+ Value_218,
+ Value_219,
+ Value_220,
+ Value_221,
+ Value_222,
+ Value_223,
+ Value_224,
+ Value_225,
+ Value_226,
+ Value_227,
+ Value_228,
+ Value_229,
+ Value_230,
+ Value_231,
+ Value_232,
+ Value_233,
+ Value_234,
+ Value_235,
+ Value_236,
+ Value_237,
+ Value_238,
+ Value_239,
+ Value_240,
+ Value_241,
+ Value_242,
+ Value_243,
+ Value_244,
+ Value_245,
+ Value_246,
+ Value_247,
+ Value_248,
+ Value_249,
+ Value_250,
+ Value_251,
+ Value_252,
+ Value_253,
+ Value_254,
+ Value_255,
+ Value_256,
+ Value_257,
+ Value_258,
+ Value_259,
+ Value_260,
+ Value_261,
+ Value_262,
+ Value_263,
+ Value_264,
+ Value_265,
+ Value_266,
+ Value_267,
+ Value_268,
+ Value_269,
+ Value_270,
+ Value_271,
+ Value_272,
+ Value_273,
+ Value_274,
+ Value_275,
+ Value_276,
+ Value_277,
+ Value_278,
+ Value_279,
+ Value_280,
+ Value_281,
+ Value_282,
+ Value_283,
+ Value_284,
+ Value_285,
+ Value_286,
+ Value_287,
+ Value_288,
+ Value_289,
+ Value_290,
+ Value_291,
+ Value_292,
+ Value_293,
+ Value_294,
+ Value_295,
+ Value_296,
+ Value_297,
+ Value_298,
+ Value_299,
+ Value_300
+ );
+
+ X : Unsigned_Enumeration := Value_23;
+
+ type Signed_Enumeration is ( SE_A, SE_B, SE_C, SE_D);
+ for Signed_Enumeration use (-1, 0, 1, 2);
+
+ Y : Signed_Enumeration := SE_D;
+
+begin
+ null; -- STOP
+end;
projects / thirdparty / binutils-gdb.git / commitdiff
