Re: A different way to bootstrap and build GCC

[Ekaitz Zarraga <ekaitz@elenq.tech>]

On 2024-11-24 13:02, Stefan wrote:
> Hi Ekaitz!
> 
>> Very interesting work. I'll read it with more detail tomorrow but at 
>> the moment it feels very similar to what we did for RISC-V
>> Is there any obvious difference in the beginning of the chain that I'm 
>> missing?
> 
> I use tcc-boot0 only to build the latest TCC with the latest musl, with 
> much less handcrafting (using make and normal installation). There are 
> less packages involved (no need for muls 1.1.24, patch, gzip, xz, flex, 
> bison).

I'll check in detail why we need those, but some are for the later GCC 
build.

> An important difference from my point of view is that I avoid (package 
> (inherit …) …).  I believe that the bootstrap packages need to be the 
> independent base.  For example in commencement.scm gcc-core-mesboot0 
> (version 2.95.3) inherits from gcc (version 11).  So changes to a newer 
> gcc will change the way how to build an older version.  This is 
> fragile.  This tears in stuff, which is useless or even problematic for 
> the bootstrap.

Oh yes! I strongly agree with this. Our GCC's are too complex and that 
gave us a lot of trouble. It's really hard to know where things are 
coming from.

It's very fragile, indeed.

> Well, finally my actual goal is to build GCC differently: There is no 
> need to patch in CROSS_C_INCLUDE_PATH etc.  The include paths to 
> standard header files must not be provided through environment variables 
> at all.  This is the cause of all the troubles people have with GCC in 
> Guix for both native and cross building.  In the end only the one 
> gcc-12-strmov-store-file-names.patch is necessary, and this not even for 
> static builds during bootstrapping.  Keeping (package (inherit …) …) 
> will tear in all the mistakes, which I try hard to avoid.

Yes. Very interesting. We can try to make something on this line.

> 
> Bye
> 
> Stefan
> 

Thanks for the explanation.

Ekaitz