Re: [RFC PATCH 2/2] fix py-value-cc.exp test for big endian target

[Pedro Alves <palves at redhat dot com>]

On 10/29/2014 06:36 AM, Yao Qi wrote:
> Victor Kamensky <victor.kamensky@linaro.org> writes:
> 
>> The reason is that test case is not endian agnostic.
>> Test program variable 'u' has type of 'union U { int a;
>> char c; };'. Test program writes 99 into u.a and expects to see
>> it in field 'u.c'. But it would only work on little endian
>> system where 'c' field of U union conicide with least
>> significant byte of 'a' field.

...

>>    U u;
>> -  u.a = 99;
>> +  u.a = 0x55000055; /* c is the same for big and little endian */
> 
> I'd like c is shown differently on big endian and little endian, and
> check c's value in different endianness.  It can be something like,
> 
>  u.a = 0x55000056 or u.a = 0x55565758

I noticed that the proposed changes assume all supported architectures
have sizeof (int) == 4, but that's not valid assumption.  E.g.,:

(gdb) set architecture m68hc11
The target architecture is assumed to be m68hc11
(gdb) p sizeof (int)
$1 = 2

(gdb) set architecture h8300
The target architecture is assumed to be h8300
(gdb) p sizeof (int)
$2 = 2

(gdb) set architecture m32c
The target architecture is assumed to be m32c
(gdb) p sizeof (int)
$3 = 2

(gdb) set architecture avr
The target architecture is assumed to be avr
(gdb) p sizeof (int)
$4 = 2

etc.

Maybe the simplest is to make the unions use uint32_t instead
of int.

Thanks,
Pedro Alves