[build, driver] RFC: Support compressed debug sections

[Rainer Orth]

Hi Gerald,

sorry for the delay, I've been away for a couple of days.

> On Tue, 3 Jun 2014, Rainer Orth wrote:
>> It's been another week, and I still need approval for the build, doc,
>> and Darwin changes:
>> 
>> 	https://gcc.gnu.org/ml/gcc-patches/2014-05/msg01860.html
>
> On the doc side, things are fine.
>
> Just a suggestion or two:
>
> +Produce compressed debug sections in DWARF format, if that is supported.
>
> Supported by what?

By the toolchain used.  TBH, I just copied that fragment from various
other debug options (-gstabs, -gcoff, -gdwarf-N).  Given the precedent
and the verbosity of a more detailed explanation, I'd leave this as is.

> "doesn't" -> "does not", especially given the emphasis we want to make
> here.

Good point, fixed.

> And could the "If the linker doesn't support writing compressed debug 
> sections, the option is rejected.  Otherwise, if the assembler doesn't 
> support them, @option{-gz} is silently ignored when producing object 
> files." be moved to the very end, or is this only applicable to the
> case where no type has been specified?

No, you're right: it's better to first explain the values for type in
the working case, then explain potential error scenarios.

The section now reads

@item -gz@r{[}=@var{type}@r{]}
@opindex gz
Produce compressed debug sections in DWARF format, if that is supported.
If @var{type} is not given, the default type depends on the capabilities
of the assembler and linker used.  @var{type} may be one of
@option{none} (don't compress debug sections), @option{zlib} (use zlib
compression in ELF gABI format), or @option{zlib-gnu} (use zlib
compression in traditional GNU format).  If the linker doesn't support
writing compressed debug sections, the option is rejected.  Otherwise,
if the assembler does not support them, @option{-gz} is silently ignored
when producing object files.

Thanks for your comments.

I'm still missing review of the build parts after three weeks and
several reminders, though.  Paolo, Nathanael, Alexandre, could one of
you please have a look?

Thanks.
        Rainer

-- 
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University