From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 98320 invoked by alias); 14 Nov 2016 15:38:28 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 98305 invoked by uid 89); 14 Nov 2016 15:38:28 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=load_lib, $srcfile, testfile, srcfile2 X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 14 Nov 2016 15:38:17 +0000 Received: from svr-orw-mbx-03.mgc.mentorg.com ([147.34.90.203]) by relay1.mentorg.com with esmtp id 1c6JKq-0003JS-BT from Luis_Gustavo@mentor.com ; Mon, 14 Nov 2016 07:38:16 -0800 Received: from [172.30.3.198] (147.34.91.1) by svr-orw-mbx-03.mgc.mentorg.com (147.34.90.203) with Microsoft SMTP Server (TLS) id 15.0.1210.3; Mon, 14 Nov 2016 07:38:13 -0800 From: Luis Machado Subject: Re: [PATCH 1/3] Fix PR12616 - gdb does not implement DW_AT_data_bit_offset Reply-To: Luis Machado References: <1479135786-31150-1-git-send-email-arnez@linux.vnet.ibm.com> <1479135786-31150-2-git-send-email-arnez@linux.vnet.ibm.com> To: Andreas Arnez , Message-ID: <21f0d548-0b8c-d0b8-657e-caaeea793ad9@codesourcery.com> Date: Mon, 14 Nov 2016 15:38:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <1479135786-31150-2-git-send-email-arnez@linux.vnet.ibm.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: svr-orw-mbx-03.mgc.mentorg.com (147.34.90.203) To svr-orw-mbx-03.mgc.mentorg.com (147.34.90.203) X-IsSubscribed: yes X-SW-Source: 2016-11/txt/msg00343.txt.bz2 On 11/14/2016 09:02 AM, Andreas Arnez wrote: > The DW_AT_data_bit_offset attribute was introduced by DWARF V4 and > allows specifying the offset of a data member within its containing > entity. But although the new attribute was intended to replace > DW_AT_bit_offset for this purpose, GDB ignores it, and thus GCC still > emits DW_AT_bit_offset instead. See also > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71669. > > This change fixes GDB's lack of support for DW_AT_data_bit_offset and > adds an appropriate test case. > > gdb/ChangeLog: > > PR gdb/12616 > * dwarf2read.c (dwarf2_add_field): Handle the DWARF V4 attribute > DW_AT_data_bit_offset. > > gdb/testsuite/ChangeLog: > > PR gdb/12616 > * gdb.dwarf2/nonvar-access.exp: New testcase. Check that GDB > respects the DW_AT_data_bit_offset attribute. > --- > gdb/dwarf2read.c | 4 ++ > gdb/testsuite/gdb.dwarf2/nonvar-access.exp | 103 +++++++++++++++++++++++++++++ > 2 files changed, 107 insertions(+) > create mode 100644 gdb/testsuite/gdb.dwarf2/nonvar-access.exp > > diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c > index 1ad6b00..558159a 100644 > --- a/gdb/dwarf2read.c > +++ b/gdb/dwarf2read.c > @@ -12584,6 +12584,10 @@ dwarf2_add_field (struct field_info *fip, struct die_info *die, > - bit_offset - FIELD_BITSIZE (*fp))); > } > } > + attr = dwarf2_attr (die, DW_AT_data_bit_offset, cu); > + if (attr != NULL) > + SET_FIELD_BITPOS (*fp, (FIELD_BITPOS (*fp) > + + dwarf2_get_attr_constant_value (attr, 0))); > > /* Get name of field. */ > fieldname = dwarf2_name (die, cu); > diff --git a/gdb/testsuite/gdb.dwarf2/nonvar-access.exp b/gdb/testsuite/gdb.dwarf2/nonvar-access.exp > new file mode 100644 > index 0000000..21532a6 > --- /dev/null > +++ b/gdb/testsuite/gdb.dwarf2/nonvar-access.exp > @@ -0,0 +1,103 @@ > +# Copyright 2016 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 . > + > +# Test accessing "non-variable" variables, i.e., variables which are > +# optimized to a constant DWARF location expression and/or > +# partially/fully optimized out. > + > +load_lib dwarf.exp > + > +if {![dwarf2_support]} { return 0 } > + > +standard_testfile main.c nonvar-access-dw.S > + > +# Make some DWARF for the test. > +set asm_file [standard_output_file $srcfile2] > + > +Dwarf::assemble $asm_file { > + cu {} { > + compile_unit { > + {DW_AT_name main.c} > + } { > + declare_labels int_type_label short_type_label > + declare_labels struct_s_label > + > + int_type_label: base_type { > + {name "int"} > + {encoding @DW_ATE_signed} > + {byte_size 4 DW_FORM_sdata} > + } > + > + struct_s_label: structure_type { > + {name s} > + {byte_size 4 DW_FORM_sdata} > + } { > + member { > + {name a} > + {type :$int_type_label} > + {data_member_location 0 DW_FORM_udata} > + {bit_size 8 DW_FORM_udata} > + } > + member { > + {name b} > + {type :$int_type_label} > + {data_bit_offset 8 DW_FORM_udata} > + {bit_size 24 DW_FORM_udata} > + } > + } > + > + DW_TAG_subprogram { > + {name main} > + {DW_AT_external 1 flag} > + {low_pc [gdb_target_symbol main] DW_FORM_addr} > + {high_pc [gdb_target_symbol main]+0x10000 DW_FORM_addr} > + } { > + DW_TAG_variable { > + {name undef_int} > + {type :$int_type_label} > + } > + DW_TAG_variable { > + {name undef_s} > + {type :$struct_s_label} > + } > + DW_TAG_variable { > + {name def_s} > + {type :$struct_s_label} > + {location { > + const1u 0 > + stack_value > + bit_piece 8 0 > + const1s -1 > + stack_value > + bit_piece 24 0 > + } SPECIAL_expr} > + } > + } > + } > + } > +} > + > +if { [prepare_for_testing ${testfile}.exp ${testfile} \ > + [list $srcfile $asm_file] {nodebug}] } { > + return -1 > +} > + > +if ![runto_main] { > + return -1 > +} > + > +gdb_test "print def_s" " = \\{a = 0, b = -1\\}" > +gdb_test "print undef_int" " = " > +gdb_test "print undef_s.a" " = " > Looks good to me.