On Tue, Apr 12, 2016 at 04:27:48PM -0400, Jason Merrill wrote:
Unfortunately, a drawback of doing this in the front end is that it's
difficult to warn only about affected cases; the front end doesn't know
what's actually going to be emitted, and has to warn conservatively, leading
to false positives particularly for inline functions.
The third patch is a sketch of an attempt to address this by delaying the
warning until expand time. We can't use front end information at this point
because it has been thrown away by pass_ipa_free_lang_data, so I'm resorting
to pre-generating the warning and stashing it away. This is several kinds of
kludge, including hashing on a call location, but it greatly improves the
accuracy of the warning. I'm hoping that someone will have a better idea
about how to approach this.
Is the intent that we emit different warnings between e.g.
-fkeep-inline-functions vs. without that, or -O0 vs. -O2?
Do you want to warn just on the out of line definitions (visible outside of
the containing TU), or also calls to those?