Re: [committed] Make main more readable

[Tom de Vries <tdevries@suse.de>]

On 3/17/21 2:18 PM, Jakub Jelinek wrote:
> On Wed, Mar 17, 2021 at 02:14:45PM +0100, Tom de Vries wrote:
>> @@ -17048,10 +17050,12 @@ main (int argc, char *argv[])
>>    outfile = NULL;
>>    hardlink = false;
>>    parse_args (argc, argv, &hardlink, &outfile);
>> +  nr_files = argc - optind;
>> +  files = (const char **)&argv[optind];
>>  
>> -  if (optind == argc || optind + 1 == argc)
>> +  if (nr_files <= 1)
>>      {
>> -      const char *file = optind == argc ? "a.out" : argv[optind];
>> +      const char *file = nr_files == 0 ? "a.out" : files[0];
> 
> Isn't that aliasing violation?

Sorry, I don't see it, can you be specific about which entity is
accessed with an incompatible type?

FWIW, I've compiled with:
...
$ make clean; make CC="gcc -Wall -fstrict-aliasing
-Wstrict-aliasing={1,2,3}"
...
and nothing in main was flagged.

OTOH, we do have things like:
...
dwz.c: In function ‘die_cu’:
dwz.c:1195:3: warning: dereferencing type-punned pointer might break
strict-aliasing rules [-Wstrict-aliasing]
   return (dw_cu_ref) die->die_parent;
   ^~~~~~
...

Thanks,
- Tom