Re: [PATCH] PR27402 Document DWARF5 support

[Mark Wielaard <mark@klomp.org>]

On Fri, 2021-02-12 at 14:14 +0100, Mark Wielaard wrote:
> 	* dwz.1: Explain what subset of DWARF5 is supported, update date,
> 	authors and add a reference to the dwz home page and mailinglist.

I pushed this.

>  dwz.1 | 35 ++++++++++++++++++++++++++++++-----
>  1 file changed, 30 insertions(+), 5 deletions(-)
> 
> diff --git a/dwz.1 b/dwz.1
> index 709506c..23ed8c1 100644
> --- a/dwz.1
> +++ b/dwz.1
> @@ -1,4 +1,4 @@
> -.TH dwz 1 "15 June 2012"
> +.TH dwz 1 "15 Feb 2021"
>  .SH NAME
>  dwz \- DWARF optimization and duplicate removal tool
>  .SH SYNOPSIS
> @@ -15,9 +15,26 @@ compilation units (CUs) for duplicated information and using
>  \fIDW_TAG_imported_unit\fR
>  to import it into each CU that needs it.
>  
> -The tool handles DWARF 32-bit format debugging sections of versions
> -2, 3 and 4 and GNU extensions on top of those, though using DWARF 4
> -or worst case DWARF 3 is strongly recommended.
> +The tool handles DWARF 32-bit format debugging sections of versions 2,
> +3, 4, most of version 5 and GNU extensions on top of those.  It is
> +strongly recommended to use at least DWARF 3, but using DWARF 4 or
> +higher will work much better.
> +
> +While most of DWARF 5 is supported dwz doesn't yet generate spec
> +compliant DWARF Supplementary Object Files (DWARF 5, section
> +7.3.6). Instead of a \fI.debug_sup\fR section it will generate a
> +\fI.gnu_debugaltlink\fR section. And it will use the
> +\fIDW_FORM_GNU_strp_alt\fR and \fIDW_FORM_GNU_reg_alt\fR, instead of
> +\fIDW_FORM_strp_sup\fR and \fIDW_FORM_ref_sup\fR to keep compatibility
> +with existing DWARF consumers.
> +
> +DWARF 4 \fI.debug_types\fR are supported, but DWARF 5 \fIDW_UT_type\fR
> +units are not. Likewise \fI.gdb_index\fR is supported, but the DWARF 5
> +\fI.debug_names\fR is not. Also some forms and sections that are only
> +emitted by GCC when generating Split DWARF, \fIDW_FORM_strx\fR and
> +\fI.debug_str_offsets\fR, \fIDW_FORM_addrx\fR and \fI.debug_addr\fR,
> +\fIDW_FORM_rnglistx\fR and \fIDW_FORM_loclistsx\fR, are not supported
> +yet.
>  
>  The tool has two main modes of operation, without the
>  \fI-m\fR option it attempts to optimize DWARF debugging information in each
> @@ -155,6 +172,14 @@ is equivalent to \fIdwz a.out\fR command.
>  .SH SEE ALSO
>  .BR http://dwarfstd.org/doc/DWARF4.pdf
>  ,
> +.BR http://dwarfstd.org/doc/DWARF5.pdf
> +,
>  .BR gdb (1).
>  .SH AUTHORS
> -Jakub Jelinek <jakub@redhat.com>.
> +Jakub Jelinek <jakub@redhat.com>,
> +Tom de Vries <tdevries@suse.de>,
> +Mark Wielaard <mark@klomp.org>
> +.SH BUGS
> +Use the Bugzilla link of the project web page or our mailing list.
> +.nh
> +.BR https://sourceware.org/dwz/ ", " <dwz@sourceware.org> .