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Re: [PATCH] Prevent LTO section collision for a symbol name starting with '*'.
- From: Jan Hubicka <hubicka at ucw dot cz>
- To: Martin Liška <mliska at suse dot cz>
- Cc: Richard Biener <richard dot guenther at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 9 Sep 2019 16:33:43 +0200
- Subject: Re: [PATCH] Prevent LTO section collision for a symbol name starting with '*'.
- References: <20190815143341.m4t76ewfi4zn3ayl@kam.mff.cuni.cz> <7c27efd6-e9dd-ac4f-ebaf-6626a226bb61@suse.cz> <1d1856dc-6e42-89ad-85ee-519b1a691afd@suse.cz> <20190823143728.favozczljnminl4d@kam.mff.cuni.cz> <bbc38fef-89ce-c433-209c-3dcd722d6ea5@suse.cz> <20190823150502.l4dnv3fxzsfhro4g@kam.mff.cuni.cz> <b00ee4a3-2246-b146-d489-09535203b557@suse.cz> <20190823223622.yq2upqnvpm574qws@kam.mff.cuni.cz> <68650f0d-1472-ba6a-0530-19ed3a011321@suse.cz> <289c7087-008d-1921-fe78-80a3e1abd986@suse.cz>
> PING^1
>
> On 8/26/19 12:04 PM, Martin Liška wrote:
> > Ok. I have a semi-working patch that has issues for inline clones.
> > When we call cgraph_node::get_untransformed_body for an inline clone,
> > then one needs to use clone_of->order to find proper LTO stream.
This seems OK to me - when using inline clone we really look for a body
of its master, so that seems OK.
> >
> > What's more problematic is that such clone can be expanded:
> >
> > f/12 (f) @0x7ffff769f708
> > Type: function definition analyzed
> > Visibility: external public
> > References: mumble.lto_priv.0/8 (write)
> > Referring:
> > Read from file: /tmp/cciAkXHp.ltrans1.o
> > Function f/12 is inline copy in main/0
> > Availability: local
> > Function flags: count:1073741824 (estimated locally) local nonfreeing_fn executed_once
> > Called by: main/0 (inlined) (1073741824 (estimated locally),1.00 per call)
> > Calls:
> >
> > and lost. So we end up with an orphan and we ICE with:
We do some work on removing unnecesary master clone when function is
fully inlined and I guess in that case you lose the order info.
One option would be to copy order into all inline clones (it does not
have very good meaning there) or do that when reshaping the tree.
This is done in cgraph_node::remove at the place clone_of is
manipulated.
This is probably bit cleaner.
> >
> > /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/lto/20081112_0.c: In function ‘main’:
> > /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/lto/20081112_0.c:10:3: fatal error: /tmp/cciAkXHp.ltrans1.o: section f is missing
> >
> > So usage of symtab_node::order seems awkward to me :/
> >
> > Martin
> >
>