[PATCH] Always emit function declaration when generating profile instrumentation

[Duncan P. N. Exon Smith]

> On 2014-May-28, at 13:43, Reid Kleckner <rnk at google.com> wrote:
> 
> On Wed, May 28, 2014 at 1:06 PM, Alex L <arphaman at gmail.com> wrote:
> Sure, We need to call CodeGenPGO::assignRegionCounters for all functions 
> because we want to emit counter variables for all functions in a translation unit, even if they aren't used.
> 
> Why do you want to emit counter variables for unused functions?

Coverage.  There's a difference between "no data" (this function wasn't
instrumented) and "never called" (counter is zero).  This patch moves unused
functions from the former category to the latter.