[PATCH] x86: reject architecture settings that are invalid to be set from the command line

H.J. Lu hjl.tools@gmail.com
Thu Jun 10 14:19:00 GMT 2010


On Thu, Jun 10, 2010 at 12:05 AM, Jan Beulich <JBeulich@novell.com> wrote:
>>>> On 09.06.10 at 18:02, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>> On Wed, Jun 9, 2010 at 8:36 AM, Jan Beulich <JBeulich@novell.com> wrote:
>>> So far, options like -march=i8086 were accepted despite the assembler
>>> subsequently choking on other consistency checks, leading to reasonably
>>> cryptic error messages. This patch makes it so that impossible
>>> architecure settings are neither accepted nor displayed (i.e. it is now
>>> made sure that those settings can only be used via directives).
>>>
>>> gas/
>>> 2010-06-09  Jan Beulich  <jbeulich@novell.com>
>>>
>>>        * config/tc-i386.c (md_parse_option): Ignore impossible processor
>>>        types.
>>>        (show_arch): New parameter 'check'.
>>>        (md_show_usage): Adjust calls to show_arch().
>>>
>>> --- 2010-06-09/gas/config/tc-i386.c     2010-06-09 17:04:12.000000000 +0200
>>> +++ 2010-06-09/gas/config/tc-i386.c     2010-06-09 17:24:59.000000000 +0200
>>> @@ -8166,6 +8166,11 @@ md_parse_option (int c, char *arg)
>>>              if (strcmp (arch, cpu_arch [j].name) == 0)
>>>                {
>>>                  /* Processor.  */
>>> +                 if (! (strcmp (default_arch, "i386")
>>> +                        ? cpu_arch[j].flags.bitfield.cpulm
>>> +                        : cpu_arch[j].flags.bitfield.cpui386))
>>> +                   continue;
>>> +
>>>                  cpu_arch_name = cpu_arch[j].name;
>>>                  cpu_sub_arch_name = NULL;
>>>                  cpu_arch_flags = cpu_arch[j].flags;
>>> @@ -8297,7 +8302,7 @@ md_parse_option (int c, char *arg)
>>>  "
>>      "
>>>
>>>  static void
>>> -show_arch (FILE *stream, int ext)
>>> +show_arch (FILE *stream, int ext, int check)
>>>  {
>>>   static char message[] = MESSAGE_TEMPLATE;
>>>   char *start = message + 27;
>>> @@ -8334,6 +8339,13 @@ show_arch (FILE *stream, int ext)
>>>          /* It is an processor.  Skip if we show only extension.  */
>>>          continue;
>>>        }
>>> +      else if (check && ! (strcmp (default_arch, "i386")
>>> +                          ? cpu_arch[j].flags.bitfield.cpulm
>>> +                          : cpu_arch[j].flags.bitfield.cpui386))
>>> +       {
>>> +         /* It is an impossible processor - skip.  */
>>> +         continue;
>>> +       }
>>>
>>>
>>
>> Do we need to check cpu_arch[j].flags.bitfield.cpulm? Can we
>> just check cpu_arch[j].flags.bitfield.cpui386 like
>>
>> if (check && !cpu_arch[j].flags.bitfield.cpui386)
>>   continue?
>>
>
> I'm of the opinion that when the assembler is in 64-bit mode it
> should reject those architectures that aren't 64-bit capable,
> otherwise specifying e.g. -march=i386 has the same ugly effect
> as has passing -march=i8086 in 32-bit mode. And if we reject
> them, we should also not display them as available.
>

On Linux/x86-64, your patch gave me

../as-new --help

  --32/--64               generate 32bit/64bit code
  --divide                ignored
  -march=CPU[,+EXTENSION...]
                          generate code for CPU and EXTENSION, CPU is one of:
                           generic64, nocona, core2, corei7, l1om, opteron, k8,
                           amdfam10, bdver1

I don't see how it can be correct since "--32 -march=i386" works fine.


-- 
H.J.



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