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[gdb/symtab] Support .debug_names section with TUs in .debug_info

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When running test-case gdb.cp/cpexprs-debug-types.exp on target board
cc-with-debug-names/gdb:debug_flags=-gdwarf-5, we get an executable with
a .debug_names section, but no .debug_types section.  For dwarf-5, the TUs
are no longer put in a separate unit, but instead they're put in the
.debug_info section.

When loading the executable, the .debug_names section is silently ignored
because of this check in dwarf2_read_debug_names:
...
  if (map->tu_count != 0)
    {
      /* We can only handle a single .debug_types when we have an
         index.  */
      if (per_bfd->types.size () != 1)
        return false;
...
which triggers because per_bfd->types.size () == 0.

The intention of the check is to make sure we don't have more that one
.debug_types section, as can happen in a object file (see PR12984):
...
$ grep "\.debug_types" 11.s
        .section        .debug_types,"G",@progbits,wt.75c042c23a9a07ee,comdat
        .section        .debug_types,"G",@progbits,wt.c59c413bf50a4607,comdat
...

Fix this by:
- changing the check condition to "per_bfd->types.size () > 1", and
- handling per_bfd->types.size () == 0.

Tested on x86_64-linux.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29385
This commit is contained in:
Tom de Vries 2022-09-06 10:15:01 +02:00
parent a4fac33dc3
commit d878bb39e4
5 changed files with 136 additions and 83 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
gdb/dwarf2/read.c
View File

@ -4736,13 +4736,16 @@ dwarf2_read_debug_names (dwarf2_per_objfile *per_objfile)
{
/* We can only handle a single .debug_types when we have an
index. */
if (per_bfd->types.size () != 1)
if (per_bfd->types.size () > 1)
{
per_bfd->all_comp_units.clear ();
return false;
}
dwarf2_section_info *section = &per_bfd->types[0];
dwarf2_section_info *section
= (per_bfd->types.size () == 1
? &per_bfd->types[0]
: &per_bfd->info);
create_signatured_type_table_from_debug_names
(per_objfile, *map, section, &per_bfd->abbrev);

18
gdb/testsuite/gdb.dwarf2/debug-names-tu-dwarf5.exp Normal file
View File

@ -0,0 +1,18 @@
# Copyright 2022 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/>.
set dwarf_version 5
source $srcdir/$subdir/debug-names-tu.exp.tcl

79
gdb/testsuite/gdb.dwarf2/debug-names-tu.exp
View File

@ -13,81 +13,6 @@
# 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 dwarf.exp
set dwarf_version 4
# This test can only be run on targets which support DWARF-2 and use gas.
if {![dwarf2_support]} {
return 0
}
standard_testfile _start.c debug-names.S
set func_info_vars \
[get_func_info _start [list debug additional_flags=-nostartfiles]]
# Create the DWARF.
set asm_file [standard_output_file $srcfile2]
Dwarf::assemble {
filename $asm_file
add_dummy_cus 0
} {
global func_info_vars
foreach var $func_info_vars {
global $var
}
cu { label cu_label } {
compile_unit {{language @DW_LANG_C}} {
subprogram {
{DW_AT_name _start}
{DW_AT_low_pc $_start_start DW_FORM_addr}
{DW_AT_high_pc $_start_end DW_FORM_addr}
}
}
}
tu { label tu_label } 0x8ece66f4224fddb3 "" {
type_unit {} {
declare_labels int_type
structure_type {
{name struct_with_int_member}
{byte_size 4 sdata}
} {
member {
{name member}
{type :$int_type}
}
}
int_type: base_type {
{name int}
{encoding @DW_ATE_signed}
{byte_size 4 sdata}
}
}
}
debug_names {} {
cu cu_label
tu tu_label
name _start subprogram cu_label 0xEDDB6232
name struct_with_int_member structure_type tu_label 0x53A2AE86
}
}
if [prepare_for_testing "failed to prepare" $testfile "${asm_file} ${srcfile}" \
[list additional_flags=-nostartfiles]] {
return -1
}
# Verify that .debug_names section is not ignored.
set index [have_index $binfile]
gdb_assert { [string equal $index "debug_names"] } ".debug_names used"
# Verify that we can find the type in the type unit.
set re \
[multi_line \
"type = struct struct_with_int_member {" \
" int member;" \
"}"]
gdb_test "ptype struct struct_with_int_member" $re
source $srcdir/$subdir/debug-names-tu.exp.tcl

94
gdb/testsuite/gdb.dwarf2/debug-names-tu.exp.tcl Normal file
View File

@ -0,0 +1,94 @@
# Copyright 2022 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 dwarf.exp
# This test can only be run on targets which support DWARF-2 and use gas.
if {![dwarf2_support]} {
return 0
}
standard_testfile _start.c debug-names.S
set func_info_vars \
[get_func_info _start [list debug additional_flags=-nostartfiles]]
# Create the DWARF.
set asm_file [standard_output_file $srcfile2]
Dwarf::assemble {
filename $asm_file
add_dummy_cus 0
} {
global dwarf_version
global func_info_vars
foreach var $func_info_vars {
global $var
}
cu { label cu_label version $dwarf_version } {
compile_unit {{language @DW_LANG_C}} {
subprogram {
{DW_AT_name _start}
{DW_AT_low_pc $_start_start DW_FORM_addr}
{DW_AT_high_pc $_start_end DW_FORM_addr}
}
}
}
tu { label tu_label version $dwarf_version } 0x8ece66f4224fddb3 "" {
type_unit {} {
declare_labels int_type
structure_type {
{name struct_with_int_member}
{byte_size 4 sdata}
} {
member {
{name member}
{type :$int_type}
}
}
int_type: base_type {
{name int}
{encoding @DW_ATE_signed}
{byte_size 4 sdata}
}
}
}
debug_names {} {
cu cu_label
tu tu_label
name _start subprogram cu_label 0xEDDB6232
name struct_with_int_member structure_type tu_label 0x53A2AE86
}
}
if [prepare_for_testing "failed to prepare" $testfile "${asm_file} ${srcfile}" \
[list additional_flags=-nostartfiles]] {
return -1
}
# Verify that .debug_names section is not ignored.
set index [have_index $binfile]
gdb_assert { [string equal $index "debug_names"] } ".debug_names used"
# Verify that we can find the type in the type unit.
set re \
[multi_line \
"type = struct struct_with_int_member {" \
" int member;" \
"}"]
gdb_test "ptype struct struct_with_int_member" $re

21
gdb/testsuite/lib/dwarf.exp
View File

@ -1563,6 +1563,7 @@ namespace eval Dwarf {
set label ""
foreach { name value } $options {
set value [uplevel 1 "subst \"$value\""]
switch -exact -- $name {
is_64 { set is_64 $value }
version { set _cu_version $value }
@ -1580,9 +1581,12 @@ namespace eval Dwarf {
}
}
set _cu_offset_size [expr { $is_64 ? 8 : 4 }]
if { $_cu_version == 5 } {
set section ".debug_info"
}
if { $_cu_is_fission } {
set section ".debug_types.dwo"
set _abbrev_section ".debug_abbrev.dwo"
set section "$section.dwo"
set _abbrev_section "$section.dwo"
}
_section $section
@ -1609,8 +1613,17 @@ namespace eval Dwarf {
}
define_label $start_label
_op .2byte $_cu_version Version
_op_offset $_cu_offset_size $my_abbrevs Abbrevs
_op .byte $_cu_addr_size "Pointer size"
# The CU header for DWARF 4 and 5 are slightly different.
if { $_cu_version == 5 } {
_op .byte 0x2 "DW_UT_type"
_op .byte $_cu_addr_size "Pointer size"
_op_offset $_cu_offset_size $my_abbrevs Abbrevs
} else {
_op_offset $_cu_offset_size $my_abbrevs Abbrevs
_op .byte $_cu_addr_size "Pointer size"
}
_op .8byte $signature Signature
if { $type_label != "" } {
uplevel declare_labels $type_label