R: Status and rationale for toplevel bootstrap (was Re: Example of debugging GCC with toplevel bootstrap)

[Marcin Dalecki]

>
> Except that host tools (fastjar mostly) are made with the *new* GCC  
> rather than the old one.

And the reason is what? I don't see even any theoretical merit in the  
whole staging thing:
1. Bugs can theoretically cancel them self out.
2. The compiler isn't stressing himself more then the target library  
stuff, which gets build anyway.
3. Why on earth should I insist to work with s self compiled gcc,  
when the native compiler is generating better and faster code?
4. Release builds for platforms are self hosted anyway so what?
5. For the case of cross compilation the whole reasoning behind it  
falls apart like a home build from cards.

But there is one thing i see for certain: It takes insane amounts of  
time, since the compiler is usually
building itself with the EXTRA SLOW version of itself containing  
runtime assertions. And thus:

6. Longer build cycles (in esp. when overlapping with the sleep  
cycle) result in less productive time and
thus likely *less* actual functional testing of the resulting  
compiler when focusing on a particular single
property of it - which is the working mode of 99% of the people here  
I assume.

Testing the resulting compiler has already a name:

make test

Everything else is just adding to confusion.