Re: RFC Adding a section group flag of 0

[Nick Clifton <nickc@redhat.com>]

Hi Ali,

  [I tried posting this to generic-abi@googlegroups.com but it was rejected.
  I hope that it will reach you via the gnu-gabi email address].

> Nick, I am curious why gcc produces these GROUP sections. Not
> challenging their right to do so, but wondering what benefit
> they derive from it.

It is not gcc itself.  It is the annobin plugin to gcc.  The plugin
creates new note sections to describe the contents of any code
section created by gcc.  It puts the note section and the code section
together into a group so that if the linker discards the code section
it will also discard the note section.

The notes are used by a security checking tool in order to make sure
that the code has been compiled according to a specified set of
guidelines.  In order for this to work, accurate notes are needed and
having extraneous notes referring to discarded code sections would
be a bad thing.

Cheers
  Nick

PS.  If you are interested in the actual code, it is under the GPL.
Check out the annobin package in Fedora.  The specification for
the notes is also available here:

  https://fedoraproject.org/wiki/Toolchain/Watermark