Re: target-specific way to make ld -N the default

[Joel Sherrill <joel dot sherrill at OARcorp dot com>]

Nick Clifton wrote:
> 
> Hi Doug,
> 
> > In the meantime there is LDEMUL_BEFORE_PARSE.
> > I see the mmix port is already making an attempt at this:
> >
> > static void
> > elfmmix_before_parse ()
> > {
> >   gld${EMULATION_NAME}_before_parse ();
> >
> >   /* Make sure we don't create a demand-paged executable.  Unfortunately
> >      this isn't changeable with a command-line option.  It makes no
> >      difference to mmo, but the sections in elf64mmix will be aligned to a
> >      page in the linked file, which is non-intuitive.  If there's ever a
> >      full system with shared libraries and demand paging, you will want to
> >      exclude this file.  */
> >   config.magic_demand_paged = false;
> > }
> 
> I rather like this solution.  It lets individual targets make up their
> own minds about the default without requiring the rather clumsy
> definition of EMBEDDED or (shudder, grin) REALLY_EMBEDDED.  The only
> problem is the lack of a way to override the default "-N" behaviour
> from the command line, and solving that is easy:

I would like hppa1.1-rtems to have this as the default behavior.  I
suspect
that since hppa1.1-rtems is essentially hppa1.1-proelf, it also needs to
be the same way.  At the moment, it can't pass autoconf tests since you
need the -N to link.

How does one enable this?

--joel sherrill

> Cheers
>         Nick
> 
> 2002-10-23  Nick Clifton  <nickc@redhat.com>
> 
>         * lexsup.c (OPTION_NO_OMAGIC): Define.
>         (ld_options): Add "no-omagic" option.
>         (parse_args): Parse --no-omagic.
>         * ld.texinfo: Document --no-omagic.
>         * NEWS: Mention new option.
> 
> Index: ld/lexsup.c
> ===================================================================
> RCS file: /cvs/src/src/ld/lexsup.c,v
> retrieving revision 1.53
> diff -c -3 -p -w -r1.53 lexsup.c
> *** ld/lexsup.c 8 Oct 2002 20:12:45 -0000       1.53
> --- ld/lexsup.c 23 Oct 2002 13:21:45 -0000
> *************** int parsing_defsym = 0;
> *** 132,137 ****
> --- 132,138 ----
>   #define OPTION_SPARE_DYNAMIC_TAGS     (OPTION_DISCARD_NONE + 1)
>   #define OPTION_NO_DEFINE_COMMON               (OPTION_SPARE_DYNAMIC_TAGS + 1)
>   #define OPTION_NOSTDLIB                       (OPTION_NO_DEFINE_COMMON + 1)
> + #define OPTION_NO_OMAGIC              (OPTION_NOSTDLIB + 1)
> 
>   /* The long options.  This structure is used for both the option
>      parsing and the help text.  */
> *************** static const struct ld_option ld_options
> *** 217,222 ****
> --- 218,225 ----
>     { {"omagic", no_argument, NULL, 'N'},
>         'N', NULL, N_("Do not page align data, do not make text readonly"),
>         EXACTLY_TWO_DASHES },
> +   { {"no-omagic", no_argument, NULL, OPTION_NO_OMAGIC},
> +       '\0', NULL, N_("Page align data, make text readonly"), EXACTLY_TWO_DASHES },
>     { {"output", required_argument, NULL, 'o'},
>         'o', N_("FILE"), N_("Set output file name"), EXACTLY_TWO_DASHES },
>     { {NULL, required_argument, NULL, '\0'},
> *************** parse_args (argc, argv)
> *** 744,749 ****
> --- 747,758 ----
>           config.text_read_only = false;
>           config.magic_demand_paged = false;
>           config.dynamic_link = false;
> +         break;
> +       case OPTION_NO_OMAGIC:
> +         config.text_read_only = true;
> +         config.magic_demand_paged = true;
> +         /* NB/ Does not set dynamic_link to true.
> +            Use --call-shared or -Bdynamic for this.  */
>           break;
>         case 'n':
>           config.magic_demand_paged = false;
> 
> Index: ld/ld.texinfo
> ===================================================================
> RCS file: /cvs/src/src/ld/ld.texinfo,v
> retrieving revision 1.73
> diff -c -3 -p -w -r1.73 ld.texinfo
> *** ld/ld.texinfo       13 Aug 2002 02:27:11 -0000      1.73
> --- ld/ld.texinfo       23 Oct 2002 13:21:47 -0000
> *************** Turn off page alignment of sections, and
> *** 660,667 ****
>   @item -N
>   @itemx --omagic
>   Set the text and data sections to be readable and writable.  Also, do
> ! not page-align the data segment.  If the output format supports Unix
> ! style magic numbers, mark the output as @code{OMAGIC}.
> 
>   @kindex -o @var{output}
>   @kindex --output=@var{output}
> --- 660,676 ----
>   @item -N
>   @itemx --omagic
>   Set the text and data sections to be readable and writable.  Also, do
> ! not page-align the data segment, and disable linking against shared
> ! libraries.  If the output format supports Unix style magic numbers,
> ! mark the output as @code{OMAGIC}.
> !
> ! @kindex --no-omagic
> ! @cindex OMAGIC
> ! @item --no-omagic
> ! This option negates most of the effects of the @option{-N} option.  It
> ! sets the text section to be read-only, and forces the data segment to
> ! be page-aligned.  Note - this option does not enable linking against
> ! shared libraries.  Use @option{-Bdynamic} for this.
> 
>   @kindex -o @var{output}
>   @kindex --output=@var{output}
> 
> Index: ld/NEWS
> ===================================================================
> RCS file: /cvs/src/src/ld/NEWS,v
> retrieving revision 1.31
> diff -c -3 -p -w -r1.31 NEWS
> *** ld/NEWS     11 Sep 2002 14:42:45 -0000      1.31
> --- ld/NEWS     23 Oct 2002 13:21:47 -0000
> ***************
> *** 1,5 ****
> --- 1,7 ----
>   -*- text -*-
> 
> + * Added --no-omagic to undo the effects of the -N option.
> +
>   * Support for Texas Instruments TMS320C4x and TMS320C3x series of
>     DSP's contributed by Michael Hayes and Svein E. Seldal.
> 

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel@OARcorp.com                 On-Line Applications Research
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