Update LTO plugin interface

[Ian Lance Taylor]

"H.J. Lu" <hjl.tools@gmail.com> writes:

> On Wed, Dec 1, 2010 at 4:48 PM, Ian Lance Taylor <iant@google.com> wrote:
>> "H.J. Lu" <hjl.tools@gmail.com> writes:
>>
>>> __udivdi3 is just an example.  It can also happen to memcpy, or
>>> any library calls generated by GCC. I am enclosing a testcase for memcpy.
>>
>> I believe we can solve that specific problem much more efficiently than
>> requiring a complete link of all the input files.  We currently solve it
>> using the -pass-through option which is passed to the linker plugin.
>> Are there any cases for which using -pass-through=-lc
>> -pass-through=-lgcc would not be a complete solution?
>>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46760

Sigh, OK, so I'll just add -pass-through=-lgcov when appropriate.

Or I'll rephrase: are there any cases for which using -pass-through for
the set of libraries that the gcc driver automatically adds to the end
of the link line would not be a complete solution?

I'm not saying -pass-through is the solution we should be using.  It's
clearly a bit of a hack.  However, I am asking the question seriously,
because if we have to do a complete relink, then let's do a complete
relink, but if we don't have to do one, let's definitely not.

Ian