Re: Merging gdc (GNU D Compiler) into gcc

[Andi Kleen <andi at firstfloor dot org>]

David Brown <david@westcontrol.com> writes:
>
> Some toolchains are configured to have a series of "init" sections at
> startup (technically, that's a matter of the default linker scripts
> and libraries rather than the compiler).  You can get code to run at
> specific times during startup by placing the instructions directly
> within these sections - but it must be "raw" instructions, not
> function definitions (and definitely no "return" statement).

Note that this only works with modern gcc with -fno-reorder-toplevel,
which disables some optimizations, and is currently broken in several
ways with LTO (in progress of being fixed)

Normally you don't get any defined order in these sections, both
unit-at-a-time and LTO do reorder. The linker may also in some
circumstances.

So it's somewhat dangerous to rely on.

-Andi