Re: Exhaustive Instructions for Toolchain Generation

[Joseph Myers <joseph at codesourcery dot com>]

There are over 25000 words of GCC installation documentation in 
install.texi, and that's not even including e.g. libstdc++ configure 
options documented elsewhere.  Other toolchain components also have such 
documentation.

It's true that, as a consequence of the toolchain being made up of 
multiple separately maintained components, the documentation focuses on 
configuration of a single build of a single component, not on issues 
relating to composing multiple such builds, of the same or different 
components, into a complete toolchain - you have to digest large amounts 
of documentation of individual components and deduce from that how to 
compose multiple builds to solve your particular problem (which is quite 
likely different from anyone else's particular problem - and there's a lot 
to digest to even get a clear enough conceptual understanding of what 
one's problem is and what the end result might look like).

But there are also plenty of toolchain build packages out there that do 
such composition, and even if each of those is solving a problem different 
from the one you have, studying those packages should give useful 
information about how multiple builds are composed that helps you develop 
your own such package.  For example, I'd advise anyone wishing to 
understand how to bootstrap a cross toolchain for a target using glibc to 
look at the build-many-glibcs.py script in glibc that I wrote, as it uses 
the preferred modern approach for building such a toolchain, whereas many 
build scripts out there have workarounds for issues with old versions of 
GCC or glibc that are no longer preferred or needed with current versions, 
into which many improvements have gone to make building such a toolchain 
smoother.

-- 
Joseph S. Myers
joseph@codesourcery.com