Re: [PATCH] Add dw2-aranges.exp

[Keith Seitz <keiths@redhat.com>]

On 11/6/24 8:32 AM, Alexandra Hájková wrote:
> 
> I modified the DWARF assembler to make it possible
> to set the Addres size to zero in a .debug_aranges section
> and used a DWARF assembler to produce the assembly file.

Nice. I've only had a quick glance at this, but something
obvious did grab my attention. Please make change locally.
You don't need a v2 just for this.

> diff --git a/gdb/testsuite/gdb.dwarf2/dw2-aranges.exp b/gdb/testsuite/gdb.dwarf2/dw2-aranges.exp
> new file mode 100644
> index 00000000000..59e7e27ac96
> --- /dev/null
> +++ b/gdb/testsuite/gdb.dwarf2/dw2-aranges.exp
> @@ -0,0 +1,44 @@
> +# Copyright 2004-2024 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/>.
> +
> +# Test .debug_aranges containing zero address_size.
> +
> +# This test can only be run on targets which support DWARF-2 and use gas.
> +# For now pick a sampling of likely targets.
> +load_lib dwarf.exp
> +
> +if {![dwarf2_support]} {
> +    verbose "Skipping $gdb_test_file_name."
> +    return 0
> +}

Nowadays, we use "require dwarf2_support".

Keith

> +
> +standard_testfile .c -2.S
> +set asm_file [standard_output_file $srcfile2]
> +
> +Dwarf::assemble $asm_file {
> +    cu { label cu_start } {
> +	compile_unit {{language @DW_LANG_C}} {
> +	}
> +    }
> +    aranges { addr_zero true } cu_start {
> +    }
> +}
> +
> +if { [prepare_for_testing "failed to prepare" $binfile  [list $asm_file $srcfile ]] } {
> +    return -1
> +}
> +
> +# Failed gdb_load would abort the testcase execution earlier.
> +pass "file loaded"
> diff --git a/gdb/testsuite/lib/dwarf.exp b/gdb/testsuite/lib/dwarf.exp
> index 6a5afec3fc8..1002c75dd09 100644
> --- a/gdb/testsuite/lib/dwarf.exp
> +++ b/gdb/testsuite/lib/dwarf.exp
> @@ -2759,8 +2759,11 @@ namespace eval Dwarf {
>   	    set addr_op .4byte
>   	}
>   
> -	_op $addr_op $arange_start "Address range start$comment"
> -	_op $addr_op $arange_length "Address range length$comment"
> +	# Do not emit address ranges when the Address size is set to 0.
> +	if { $_addr_size > 0 } {
> +	    _op $addr_op $arange_start "Address range start$comment"
> +	    _op $addr_op $arange_length "Address range length$comment"
> +	}
>       }
>   
>       # Emit a DWARF .debug_aranges unit.
> @@ -2797,6 +2800,7 @@ namespace eval Dwarf {
>   	    { cu_is_64 0 }
>   	    { section_version 2 }
>   	    { seg_size 0 }
> +	    { addr_zero false }
>   	}
>   	set _seg_size $seg_size
>   
> @@ -2806,6 +2810,10 @@ namespace eval Dwarf {
>   	    set _addr_size 4
>   	}
>   
> +	if { $addr_zero } {
> +	    set _addr_size 0
> +	}
> +
>   	# Switch to .debug_aranges section.
>   	_section .debug_aranges
>   
> @@ -2853,6 +2861,9 @@ namespace eval Dwarf {
>   
>   	# Padding.
>   	set tuple_size [expr 2 * $_addr_size + $_seg_size]
> +	if {$tuple_size == 0} {
> +	    set tuple_size 1
> +	}
>   	while { 1 } {
>   	    if { [expr $offset % $tuple_size] == 0 } {
>   		break