[dmd-internals] Testcase in test42.d

[Iain Buclaw]

On 6 April 2013 01:49, Iain Buclaw <ibuclaw at ubuntu.com> wrote:

> On 6 April 2013 01:02, Walter Bright <walter at digitalmars.com> wrote:
>
>>
>> On 4/5/2013 3:56 PM, David Nadlinger wrote:
>>
>>>
>>> My point here is that C compiler might not align the same data to 16
>>> bytes.
>>>
>>
>> Consider the following C code:
>> ------------------------------**--------
>> #include <stdio.h>
>>
>> struct S {
>>     int a[4];
>> };
>>
>> int x;
>> struct S s;
>>
>> struct T {
>>     int t;
>>     struct S s;
>> };
>>
>> void main()
>> {
>>     printf("%p %p %d\n", &x, &s, sizeof(struct T));
>> }
>> ------------------------------
>>
>> I compiled it with gcc under Linux. x is aligned to 4 bytes, and s is
>> aligned to 16 bytes (you can see this using dumpobj on the object file).
>> The sizeof(struct T) is also 20 bytes, just like in dmd.
>>
>> dmd is behaving just like gcc does.
>>
>>
> You can also see more in the assembly produced by gcc.
>
> 32bit:
>         .comm   x,4,4
>         .comm   s,16,4
> ---
> 64bit:
>         .comm   x,4,4
>         .comm   s,16,16
>
>
> Looks like dmd is behaving just like 64bit gcc does. But not 32bit.
>
>
Oh, and just incase it wasn't clear from my part (not sure about the case
with ldc), but it is only x86 where this test is failing with gdc.

-- 
Iain Buclaw

*(p < e ? p++ : p) = (c & 0x0f) + '0';
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