Self-hosting D compiler -- Coming Real Soon Now(tm)

[Iain Buclaw via Digitalmars-d]

On 11 September 2014 04:50, Iain Buclaw <ibuclaw at gdcproject.org> wrote:
> On 10 Sep 2014 22:13, "H. S. Teoh via Digitalmars-d"
> <digitalmars-d at puremagic.com> wrote:
>>
>> On Wed, Sep 10, 2014 at 10:58:00PM +0200, Andrej Mitrovic via
>> Digitalmars-d wrote:
>> > On 9/10/14, H. S. Teoh via Digitalmars-d <digitalmars-d at puremagic.com>
>> > wrote:
>> > > - Decide on policy on how many previous releases the current
>> > >   codebase must be buildable on (currently, it's just the previous
>> > >   release, as I understand it);
>> >
>> > If by current you mean git-head, only git-head versions of DMD are
>> > compatible with git-head versions of druntime and phobos. Meaning it's
>> > normal that an e.g. 2.066 compiler will not build a Phobos commit
>> > after the commit tagged v2.066 (it may work for a while, but things
>> > usually break quick enough either through things like mangling changes
>> > or accepts-invalid bug fixes, to name a few).
>>
>> If self-hosting is ever going to take off, we're gonna hafta restrict
>> dmd source code to be compilable with at least the previous dmd release.
>> Otherwise, we may end up with a compiler that can't be compiled unless
>> you've already compiled it first.
>>
>
> For GDC (and distributions that ship GDC), that would extend to 3 or 4
> versions, as gcc releases are a round about, or just over yearly.
>

By way of example, the version of D shipped with gcc-4.9 in
Debian/Ubuntu is 2.065, if we were to switch now, then that compiler
version will need to be able to build whatever will be the current
when gcc-5.0 comes out.

Iain.