On Tue, 25 Mar 2014, Jan Hubicka wrote:
> >
> > Currently a _lot_ of packages fail to build with LTO because LTO
> > messes up fortify wrappers by replacing the call to the alias with
> > the symbol itself, making the wrapper look like infinitely
> > recursing.
> >
> > The following patch fixes this by dropping the bodies of
> > DECL_EXTERN always-inline functions on the floor before IPA
> > (and when doing LTO). IMHO we should at some point do this
> > unconditional on LTO as the early inliner is supposed to
> > remove all references to always-inline functions.
> >
> > I'm not 100% sure about the cgraph API use to drop the function
> > body, but at least it seems to work ;) I'm not sure if we want
> > to restrict the set of functions to apply this even more than
> > just those with always-inline and DECL_EXTERNAL set?
> >
> > Now double-checking with a fortified LTO bootstrap.
> >
> > Ok for trunk?
> >
> > Thanks,
> > Richard.
> >
> > 2014-03-24 Richard Biener <rguent...@suse.de>
> >
> > PR lto/59626
> > * passes.c (ipa_write_summaries): Drop function bodies of
> > extern always-inline functions.
> >
> > * gcc.dg/lto/pr59626_0.c: New testcase.
> > * gcc.dg/lto/pr59626_1.c: Likewise.
> >
> Hi,
> do you see some problem with this approach? Unlike in dropping for
> ipa_write_summaries
> it drops just after early optimizations and it is done unconditonally.
> I see it kills every cross module inlining of extern inlines, but so does
> your patch.
> This may make difference for C++ implicit extern inlines (keyed functions)
> where I can
> imagine users both to declare them always inline and then call indirectly...
> I do it unconditionally because I do not like much of idea of making the LTO
> and non-LTO
> pipelines diverging even more.
Well - it doesn't fix the testcase for me.
Richard.
> Honza
>
> Index: ipa.c
> ===================================================================
> --- ipa.c (revision 208798)
> +++ ipa.c (working copy)
> @@ -139,7 +139,10 @@ process_references (struct ipa_ref_list
>
> if (node->definition && !node->in_other_partition
> && ((!DECL_EXTERNAL (node->decl) || node->alias)
> - || (before_inlining_p
> + || (((before_inlining_p
> + && (cgraph_state < CGRAPH_STATE_IPA_SSA
> + || !lookup_attribute ("always_inline",
> + DECL_ATTRIBUTES (node->decl)))))
> /* We use variable constructors during late complation for
> constant folding. Keep references alive so partitioning
> knows about potential references. */
> @@ -191,7 +194,10 @@ walk_polymorphic_call_targets (pointer_s
> /* Prior inlining, keep alive bodies of possible targets for
> devirtualization. */
> if (n->definition
> - && before_inlining_p)
> + && (before_inlining_p
> + && (cgraph_state < CGRAPH_STATE_IPA_SSA
> + || !lookup_attribute ("always_inline",
> + DECL_ATTRIBUTES (n->decl)))))
> pointer_set_insert (reachable, n);
>
> /* Even after inlining we want to keep the possible targets in the
>
>
