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Re: Historic C++ ABI question
- From: Jonathan Wakely <jwakely dot gcc at gmail dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: "gcc-help at gcc dot gnu dot org" <gcc-help at gcc dot gnu dot org>
- Date: Mon, 6 Jun 2016 11:04:00 +0100
- Subject: Re: Historic C++ ABI question
- Authentication-results: sourceware.org; auth=none
- References: <18144222-fbcc-234f-7032-f633dd64aeee at redhat dot com> <5f687cb8-6d42-33e6-de76-edf470724eac at redhat dot com>
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@