https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78191
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2016-11-03
Assignee|unassigned at gcc dot gnu.org |jakub at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 39954
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39954&action=edit
gcc7-pr78191.patch
The bug is specific I think just to -gdwarf-{2,3} -gno-strict-dwarf, where
DW_FORM_exprloc can't be used for location expressions and some location
expression contains DW_OP_GNU_{{const,regval,deref}_type,convert,reinterpret}
and there are at least 128 die abbreviations used by more than one DIE.
Because of the lack of DW_FORM_exprloc we need to decide on
DW_FORM_block{1,2,4} and size the location expression, for that we need to know
the DIE offsets of base offset DIEs that are referenced and for that their size
and their abbreviation values need to be constant, so the optimize_abbrev_table
opts that reorder abbreviation numbers by decreasing usage count or for
-gdwarf-5 attempt to optimize implicit constants can't be done for the CU and
base types.
For -gdwarf-4 and above, we can emit DW_FORM_exprloc, so value_format doesn't
need to compute any sizes and thus calc_base_type_die_sizes shouldn't be
called.
