[Bug other/46770] Replace .ctors/.dtors with .init_array/.fini_array on targets supporting them

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46770

--- Comment #80 from H.J. Lu <hjl.tools at gmail dot com> 2012-04-17 18:12:41 UTC ---
(In reply to comment #79)
> 
> As Paul noted, this is a moot point in practice for .ctors, since GCC emits
> only a single .ctors entry per TU, but it could be significant for assembly
> code or for TUs with .init_array sections.
> 

That is my concern. .init_array section in the same TU can may have
more than one entry due to:

1. Assembly code.
2. constructor attribute in C source.
3. .init_array section attribute in C source.

We need to spell out exactly what --reverse-init-array should do.