From 5b151607e1faf27238e9dce6d3124741779dcc3a Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Thu, 28 Oct 2021 10:43:34 +0200 Subject: [PATCH] [gdb/symtab] Handle DW_AT_string_length with location list Consider a fortran routine where a string variable s is modified: ... subroutine f(s) character*(*) s print *, s s(1:3) = 'oof' print *, s end subroutine f ... When compiling with optimization level -O1 and printing the type of variable s we get: ... $ gdb -q -batch outputs/gdb.opt/fortran-string/fortran-string \ -ex "b f" \ -ex run \ -ex "ptype s" Breakpoint 1 at 0x4006f7: file fortran-string.f90, line 21. Breakpoint 1, f (s=..., _s=_s@entry=3) at fortran-string.f90:21 21 subroutine f(s) type = character*1 ... while with -O0 we have instead: ... type = character (3) ... The problem is that the type of s is: ... <1><2d6>: Abbrev Number: 21 (DW_TAG_string_type) <2d7> DW_AT_string_length: 0xbf (location list) <2db> DW_AT_byte_size : 4 ... where the DW_AT_string_length is a location list, a case that is not handled by attr_to_dynamic_prop. Fix this by handling attr->form_is_section_offset () in attr_to_dynamic_prop. Tested on x86_64-linux. The test-case is based on gdb.opt/fortran-string.exp from https://src.fedoraproject.org/rpms/gdb/raw/f32/f/gdb-archer-vla-tests.patch . I've updated the copyrights to stretch to 2021. [ I've tried to create a dwarf assembly test-case for this, but didn't manage. ] Co-Authored-By: Jan Kratochvil Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=26910 --- gdb/dwarf2/read.c | 24 ++++++++++++--- gdb/testsuite/gdb.opt/fortran-string.exp | 38 ++++++++++++++++++++++++ gdb/testsuite/gdb.opt/fortran-string.f90 | 27 +++++++++++++++++ 3 files changed, 85 insertions(+), 4 deletions(-) create mode 100644 gdb/testsuite/gdb.opt/fortran-string.exp create mode 100644 gdb/testsuite/gdb.opt/fortran-string.f90 diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index bd0754618d0..af184d4d1fd 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -18468,14 +18468,30 @@ attr_to_dynamic_prop (const struct attribute *attr, struct die_info *die, } else if (attr->form_is_constant ()) prop->set_const_val (attr->constant_value (0)); - else + else if (attr->form_is_section_offset ()) { - dwarf2_invalid_attrib_class_complaint (dwarf_form_name (attr->form), - dwarf2_name (die, cu)); - return 0; + switch (attr->name) + { + case DW_AT_string_length: + baton = XOBNEW (obstack, struct dwarf2_property_baton); + baton->property_type = default_type; + fill_in_loclist_baton (cu, &baton->loclist, attr); + prop->set_loclist (baton); + gdb_assert (prop->baton () != NULL); + break; + default: + goto invalid; + } } + else + goto invalid; return 1; + + invalid: + dwarf2_invalid_attrib_class_complaint (dwarf_form_name (attr->form), + dwarf2_name (die, cu)); + return 0; } /* See read.h. */ diff --git a/gdb/testsuite/gdb.opt/fortran-string.exp b/gdb/testsuite/gdb.opt/fortran-string.exp new file mode 100644 index 00000000000..9bf6269f840 --- /dev/null +++ b/gdb/testsuite/gdb.opt/fortran-string.exp @@ -0,0 +1,38 @@ +# Copyright 2009-2021 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 GDB can cope with Fortran strings having their length present in a CPU +# register. With -O0 the string length is passed on the stack. To make this +# test meaningful the follow assertion should pass. It is not being checked +# here as the "_s" symbol is compiler dependent: +# (gdb) info address _s +# Symbol "_s" is a variable in register XX. + +standard_testfile .f90 + +if { [prepare_for_testing "prepare for testing" ${testfile} ${srcfile} \ + {debug f90 additional_flags=-O1}] } { + return -1 +} + +if ![runto f] then { + perror "couldn't run to f" + continue +} + +gdb_test_no_output "set print frame-arguments all" +gdb_test "frame" ".*s='foo'.*" +gdb_test "ptype s" "type = character \\(3\\)" +gdb_test "p s" "\\$\[0-9\]* = 'foo'" diff --git a/gdb/testsuite/gdb.opt/fortran-string.f90 b/gdb/testsuite/gdb.opt/fortran-string.f90 new file mode 100644 index 00000000000..71b6baea05a --- /dev/null +++ b/gdb/testsuite/gdb.opt/fortran-string.f90 @@ -0,0 +1,27 @@ +! Copyright 2009-2021 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 . + +subroutine f(s) + character*(*) s + print *, s + s(1:3) = 'oof' + print *, s +end subroutine f + +program main + character*3 s; + s = 'foo' + call f (s) +end program main -- 2.30.2