When running test-case gdb.cp/cpexprs-debug-types.exp with target board cc-with-debug-names, I run into: ... (gdb) print base::operator new^M ^M ^M Fatal signal: Segmentation fault^M ----- Backtrace -----^M 0x57ea46 gdb_internal_backtrace_1^M /home/vries/gdb_versions/devel/src/gdb/bt-utils.c:122^M 0x57eae9 _Z22gdb_internal_backtracev^M /home/vries/gdb_versions/devel/src/gdb/bt-utils.c:168^M 0x75b8ad handle_fatal_signal^M /home/vries/gdb_versions/devel/src/gdb/event-top.c:946^M 0x75ba19 handle_sigsegv^M /home/vries/gdb_versions/devel/src/gdb/event-top.c:1019^M 0x7f795f46a8bf ???^M 0x6d3cb1 _ZNK18dwarf2_per_objfile12symtab_set_pEPK18dwarf2_per_cu_data^M /home/vries/gdb_versions/devel/src/gdb/dwarf2/read.c:1515^M ...
Happens because dwarf2_per_objfile::symtab_set_p is called with per_cu == nullptr. This happens the first time we process a DW_IDX_type_unit in dw2_debug_names_iterator::next: ... case DW_IDX_type_unit: /* Don't crash on bad data. */ if (ull >= per_bfd->tu_stats.nr_tus) { complaint (_(".debug_names entry has bad TU index %s" " [in module %s]"), pulongest (ull), objfile_name (objfile)); continue; } per_cu = per_bfd->get_cu (ull + per_bfd->tu_stats.nr_tus); break; ... We have a reference to type unit 14: ... (gdb) p ull $2 = 14 ... The CU table in .debug_names contains 6 entries (0-5) and the TU table contains 62 (0-61). So type unit 14 is a valid index. We correctly kept track of the number of TUs: ... (gdb) p per_bfd->tu_stats.nr_tus $3 = 62 ... And the all_comp_units.size () is 68, which indeed 62 + 6: ... (gdb) s dwarf2_per_bfd::get_cu (this=0x3659360, index=76) at /home/vries/gdb_versions/devel/src/gdb/dwarf2/read.h:401 401 return this->all_comp_units[index].get (); (gdb) p this->all_comp_units.size () $4 = 68 ... However, the index used is 76, which is too big. Looking at the CU/TU table, we have: ... CU table: [ 0] 0x0 [ 1] 0x2e [ 2] 0x6d [ 3] 0x8f [ 4] 0x4db7 [ 5] 0x4f6f TU table: [ 0] 0x0 [ 1] 0x15b [ 2] 0x2e0 ... And: ... (gdb) p this->all_comp_units[0].get().sect_off $16 = 0 (gdb) p this->all_comp_units[1].get().sect_off $17 = (unknown: 0x2e) (gdb) p this->all_comp_units[2].get().sect_off $18 = (unknown: 0x6d) ... and: ... (gdb) p this->all_comp_units[6].get().sect_off $19 = 0 (gdb) p this->all_comp_units[7].get().sect_off $20 = (unknown: 0x15b) (gdb) p this->all_comp_units[8].get().sect_off $21 = (unknown: 0x2e0) ... So, at first glance, it seems the fix should be something like: ... - per_cu = per_bfd->get_cu (ull + per_bfd->tu_stats.nr_tus); + per_cu = per_bfd->get_cu (ull + per_bfd->cu_stats.nr_cus); ...
Yep, that fixes it: ... diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index 23fe5679cbd..9f92b420645 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -4991,7 +4991,11 @@ dw2_debug_names_iterator::next () objfile_name (objfile)); continue; } - per_cu = per_bfd->get_cu (ull + per_bfd->tu_stats.nr_tus); + { + int nr_cus = (per_bfd->all_comp_units.size () + - per_bfd->tu_stats.nr_tus); + per_cu = per_bfd->get_cu (nr_cus + ull); + } break; case DW_IDX_die_offset: /* In a per-CU index (as opposed to a per-module index), index ...
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=3fa23bb5a5320dd82d32455036d59a026929fc2f
Fixed.
*** Bug 29323 has been marked as a duplicate of this bug. ***