https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84456
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, the bug is that GCC 7's dw_loc_list tail:
/* Try to avoid the overhead of a location list emitting a location
expression instead, but only if we didn't have more than one
location entry in the first place. If some entries were not
representable, we don't want to pretend a single entry that was
applies to the entire scope in which the variable is
available. */
if (list && loc_list->first->next)
gen_llsym (list);
has been replaced with:
/* Try to avoid the overhead of a location list emitting a location
expression instead, but only if we didn't have more than one
location entry in the first place. If some entries were not
representable, we don't want to pretend a single entry that was
applies to the entire scope in which the variable is
available. */
maybe_gen_llsym (list);
where maybe_gen_llsym has:
if (!list || (!list->dw_loc_next && !loc_list_has_views (list)))
return;
gen_llsym (list);
That is not really equivalent; it is equivalent in the other spot, where it
used to be:
if (list && list->dw_loc_next)
gen_llsym (list);
and now is:
maybe_gen_llsym (list);
but in the first case, we were calling gen_llsym even when list &&
list->dw_loc_next == NULL, intentionally so, that means we got some location
note that would start the range and then another one that resets the range.
The following patch fixes this for me:
2018-03-08 Jakub Jelinek <ja...@redhat.com>
PR debug/84456
* dwarf2out.c (dw_loc_list): If list && loc_list->first->next, call
gen_llsym, otherwise call maybe_gen_llsym.
--- gcc/dwarf2out.c.jj 2018-03-02 00:15:54.704780976 +0100
+++ gcc/dwarf2out.c 2018-03-08 12:54:01.794054675 +0100
@@ -17076,7 +17076,10 @@ dw_loc_list (var_loc_list *loc_list, tre
representable, we don't want to pretend a single entry that was
applies to the entire scope in which the variable is
available. */
- maybe_gen_llsym (list);
+ if (list && loc_list->first->next)
+ gen_llsym (list);
+ else
+ maybe_gen_llsym (list);
return list;
}
The maybe_gen_llsym will cover the case when -gvariable-location-views and
list && list->dw_loc_next == NULL && loc_list->first->next == NULL and the
single entry list has some non-zero view.
