Gold linker patch to split unlikely text into a separate segment

["Sriraman Tallam via binutils" <binutils at sourceware dot org>]

Hi,

     This patch adds an option to gold to create a new ELF segment for
code determined unlikely by the compiler.  Currently, this can be done
with a linker plugin but I was wondering if it is fine to have this
support in gold with an option for ease of use.

     The advantages of doing this are:

* We could only map the hot segment to huge pages to keep iTLB misses low
* We could munlock the unlikely segment

Is this alright?

ChangeLog entry:

* options.h (text_unlikely_segment): New option.
* layout.cc (Layout::layout): Create new output section
for .text.unlikely sections with the new option.
(Layout::segment_precedes): Check for the new option
when segment flags match.

Patch attached.

Thanks
Sri

Attachment: segment_split.txt
Description: Text document