On 3/1/23 08:09, Jakub Jelinek wrote:
On Wed, Mar 01, 2023 at 01:07:02PM +0000, Richard Biener wrote:
When combining -g1 with -flto we run into the DIE location annotation
machinery for globals calling dwarf2out_late_global_decl but not
having any early generated DIE for function scope statics. In
this process we'd generate a limbo DIE since also the function scope
doesn't have any early generated DIE. The limbo handling then tries
to force a DIE for the context chain which ultimatively fails and
ICEs at the std namespace decl because at -g1 we don't represent that.
The following avoids this situation by making sure to never generate
any limbo DIEs from dwarf2out_late_global_decl in the in_lto_p path
but instead for function scope globals rely on DIE generation for
the function to output a DIE for the local static (which doesn't
happen for -g1).
So the issue is that we're trying to force out a DIE for a decl that we
wouldn't have generated without -flto? How is it avoided in the non-LTO
case?
I explored a lot of other options to fix this but in the end this
seems to be the most spot-on fix with the least risk of unwanted
effects.
LTO bootstrapped on x86_64-unknown-linux-gnu (running into PR108984),
bootstrapped and tested on x86_64-unknown-linux-gnu.
OK?
Thanks,
Richard.
PR debug/108772
* dwarf2out.cc (dwarf2out_late_global_decl): Do not
generate a DIE for a function scope static when we do
not have a DIE for the function already.
* g++.dg/lto/pr108772_0.C: New testcase.
LGTM, but please give Jason a day to chime in if he disagrees.
Jakub
