Historic C++ ABI question

[Jonathan Wakely]

On 1 June 2016 at 18:57, Florian Weimer wrote:
> On 06/01/2016 05:39 PM, Florian Weimer wrote:
>>
>> Given these definitions
>>
>> struct base
>> {
>>   int a;
>>   int b;
>> };
>>
>> struct plus : base
>> {
>>   virtual ~plus();
>> };
>>
>> is there a historic C++ ABI which puts the vtable at offset 8 in struct
>> plus (after the fields from struct base)?  This must have been before
>> the Itanium C++ ABI.
>
>
> GCC 2.95 on i386 produces such layout.
>
> Was it possible to generate it with later compilers?   The GCC 3.0 release
> notes say that a new C++ ABI was implemented.  Was there really no backwards
> compatibility?

I don't think so, but you might get a more definite answer on gcc@
rather than gcc-help@