Re: [PATCH v7 3/8] Use xml-syscall to compare syscall numbers in arm_linux_sigreturn_return-addr.

[Pedro Alves <palves@redhat.com>]

On 12/11/2015 12:29 PM, Antoine Tremblay wrote:
> 
> 
> On 12/11/2015 06:29 AM, Yao Qi wrote:
>> Antoine Tremblay <antoine.tremblay@ericsson.com> writes:
>>
>>> It also adds a new function to xml-syscall.h/c to compare syscalls numbers
>>> called is_syscall.
>>
>> Why don't we use existing get_syscall_by_name in
>> arm_linux_sigreturn_return_addr rather than adding a new function is_syscall?
>>
> 
> This is because it complicated the code a lot just to compare a syscall 
> I have to do what is in the is_syscall function.
> 
> And I have to do that over and over... so might as well be in a function ?
> 
> 

The issue is the having to handle the struct syscall instance, right?
So instead of is_syscall, you could add a function that returns the
syscall number directly, like:

 int
 get_syscall_number (struct gdbarch *gdbarch,
                     const char *syscall_name)
 {
   init_syscalls_info (gdbarch);

   return xml_get_syscall_number (gdbarch, syscall_name);
 }

and then users could use the more natural == comparison:

   /* Is this a sigreturn or rt_sigreturn syscall?  */
-  if (svc_number == 119 || svc_number == 173)
+  if (get_syscall_number (gdbarch, "sigreturn") == svc_number)
+      || get_syscall_number (gdbarch, "rt_sigreturn") == svc_number))
     {

and maybe other places could be simplified to use get_syscall_number
for other purposes than direct comparison.

Thanks,
Pedro Alves