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

[kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)]

    Of course in this case HOST_WIDE_INT is 64.  I think we do guarantee 
    that, or cross compilation would be in big trouble.

No, it wouldn't be in big trouble: it didn't used to be 64 and it wasn't in
big trouble.  The issue isn't if it *works*, but if the two compilers do the
identical thing with the same source and that's not something we guarantee.

The point is that 32->64 is a cross-compiler and it's only meaningful to talk
about "bootstrapping" a native compiler.

    Comparing:

      cd gcc                      make stage1-bubble (*)
      make                        cd gcc
      <<< debug >>>               <<< debug >>>
      make bootstrap              cd ..
      make gnatlib_and_tools      make

I'm confused as to exactly what the "make" on the right side builds.  Of
course I forgot about the upper-level "make" before the "check", but it's not
needed before "check-ada": for that all I want is "make gnatlib_and_tools",
but you don't show the equivalent for that.

    (**) Thanks to other Ada build improvements by Nathanael Nerode, this
    subsumes both "make bootstrap" within the gcc directory plus "make
    gnatlib_and_tools".

But I don't *want* to use the libada mechanism: I need to use the present
mechanism where the Ada library and tools are built within the gcc/
directory. It's indeed nice to have the libada mechanism as an option when a
full build is done, but it's not what's wanted during a development cycle.