[patch] Gold linker patch to provide plugin support for mapping some text sections to an unique ELF segment.

[Sriraman Tallam]

Ping.

Thanks,
-Sri.

On Fri, Jul 20, 2012 at 5:28 PM, Sriraman Tallam <tmsriram@google.com> wrote:
> Hi,
>
>   This patch allows plugins to specify that a subset of sections are
> to be mapped to an unique segment.  This is useful, for instance, when
> a set of functions that are determined to be hot can be placed in an
> unique segment which can then be mapped to huge text pages. It has
> been found for some Google applications that mapping functions to huge
> pages, along with function layout, provides a significant performance
> benefit and this feature can take this further by only mapping certain
> functions to huge pages, which requires that they be placed in an
> unique segment.
>
> The plugin needs to specify a list of sections that have to mapped to
> an unique segment.  The plugin can also specify any additional segment
> flags to be set. The segment flag bits 3 to 19 seem to be available
> and can be set to mark some segments which can later be mapped to huge
> pages.  The flags which would be set by default, bits 0-2, cannot be
> unset by the plugin.
>
> Thoughts?
>
> Patch attached.
>
> Thanks,
> -Sri.