I noticed this code in dw2_debug_names_iterator::next:
...
case DW_IDX_compile_unit:
/* Don't crash on bad data. */
if (ull >= per_bfd->all_comp_units.size ())
{
complaint (_(".debug_names entry has bad CU index %s"
" [in module %s]"),
pulongest (ull),
objfile_name (objfile));
continue;
}
per_cu = per_bfd->get_cu (ull);
break;
...
This code used to DTRT, before we started keeping both CUs and TUs in
all_comp_units.
Fix by using "per_bfd->all_comp_units.size () - per_bfd->tu_stats.nr_tus"
instead.
It's hard to produce a test-case for this, but let's try at least to trigger
the complaint somehow. We start out by creating an exec with .debug_types and
.debug_names:
...
$ gcc -g ~/hello.c -fdebug-types-section
$ gdb-add-index -dwarf-5 a.out
...
and verify that we don't see any complaints:
...
$ gdb -q -batch -iex "set complaints 100" ./a.out
...
We look at the CU and TU table using readelf -w and conclude that we have
nr_cus == 6 and nr_tus == 1.
Now override ull in dw2_debug_names_iterator::next for the DW_IDX_compile_unit
case to 6, and we have:
...
$ gdb -q -batch -iex "set complaints 100" ./a.out
During symbol reading: .debug_names entry has bad CU index 6 [in module a.out]
...
After this, it still crashes because this code in
dw2_debug_names_iterator::next:
...
/* Skip if already read in. */
if (m_per_objfile->symtab_set_p (per_cu))
goto again;
...
is called with per_cu == nullptr.
Fix this by skipping the entry if per_cu == nullptr.
Now revert the fix and observe that the complaint disappears, so we've
confirmed that the fix is required.
A somewhat similar issue for .gdb_index in dw2_symtab_iter_next has been filed
as PR29367.
Tested on x86_64-linux, with native and target board cc-with-debug-names.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29336
2fe9a3c41f