Re: [PATCH] gas/arc: Allow --with-cpu configure option to change default cpu

[Nick Clifton <nickc at redhat dot com>]

Hi Andrew,

> I've attached a new revision, this includes NEWS entry, and the help
> text that makes it clear the option is only supported on ARC.

Sorry - this version still has a few problems:

  1.  If you configure a toolchain as "--target=arc-elf", but do
      not provide a --with-cpu= option, then the assembler fails
      to run, producing this error:

        Assembler messages:
        Fatal error: unknown architecture: 

     This is because the config script sets TARGET_WITH_CPU to be "".


  (In the code fragments below I have assumed that this has been corrected
   so that TARGET_WITH_CPU is not defined unless --with-cpu is used).


  2. The patch does not provide a way for the user to find out the default
     cpu type.  Ideally this should be included in the --help output, like this:

@@ -3401,7 +3405,7 @@ md_show_usage (FILE *stream)
 {
   fprintf (stream, _("ARC-specific assembler options:\n"));
 
-  fprintf (stream, "  -mcpu=<cpu name>\t  assemble for CPU <cpu name>\n");
+  fprintf (stream, "  -mcpu=<cpu name>\t  assemble for CPU <cpu name> (default: %s)\n", TARGET_WITH_CPU);


      Additionally, you might like to extend the text displayed with --version
      so that it includes the cpu type as well.  Like this:

diff --git a/gas/as.c b/gas/as.c
index 8784fb4..90f18c0 100644
--- a/gas/as.c
+++ b/gas/as.c
@@ -665,8 +665,13 @@ parse_args (int * pargc, char *** pargv)
 This program is free software; you may redistribute it under the terms of\n\
 the GNU General Public License version 3 or later.\n\
 This program has absolutely no warranty.\n"));
+#ifdef TARGET_WITH_CPU
+         printf (_("This assembler was configured for a target of `%s' and default cpu type `%s'\n"),
+                 TARGET_ALIAS, TARGET_WITH_CPU);
+#else
          printf (_("This assembler was configured for a target of `%s'.\n"),
                  TARGET_ALIAS);
+#endif
          exit (EXIT_SUCCESS);
 
        case OPTION_EMULATION:


  3. Please could you change:

> +dnl Option --with-cpu=TYPE allows configure type control of the default
> +dnl cpu type within the assembler.  Not all targets support this option
> +dnl yet, which is why there is no help string, check the code to see if
> +dnl your target supports this option.
> +AC_ARG_WITH(cpu,
> +            AS_HELP_STRING([--with-cpu=CPU],
> +            [default cpu variant is CPU (only supported on ARC)]),
> +            [],[])

to:

  +dnl Option --with-cpu=TYPE allows configure type control of the default
  +dnl cpu type within the assembler.  Currently only the ARC target
  +dnl supports this feature, but others may be added in the future.
  +AC_ARG_WITH(cpu,
  +            AS_HELP_STRING([--with-cpu=CPU],
  +            [default cpu variant is CPU (currently only supported on ARC)]),
  +            [],[])


  4. Optional: There is no error checking of with --with-cpu value.  So I can
     configure with --with-cpu=fred and not get an error until I try to run the
     assembler.  Fixing this might not actually be a good idea since it will 
     involve duplicating the list of acceptable cpu names, meaning that there
     would then be two lists that need to be kept in sync.

Cheers
  Nick