[Bug lto/69133] New: LTO segfault in lto_get_decl_mapping() on 483.xalancbmk with -flto-partitions=none

[prathamesh3492 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69133

            Bug ID: 69133
           Summary: LTO segfault in lto_get_decl_mapping() on
                    483.xalancbmk with -flto-partitions=none
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: prathamesh3492 at gcc dot gnu.org
  Target Milestone: ---

483.xalancbmk from SPEC CPU2006 fails to build with -flto -flto-partitions=none

Trace: 
lto1: internal compiler error: Segmentation fault
0xa4432f crash_signal
    ../../gcc/gcc/toplev.c:334
0x90f748 lto_get_decl_name_mapping(lto_file_decl_data*, char const*)
    ../../gcc/gcc/lto-section-in.c:352
0x690659 cgraph_node::get_untransformed_body()
    ../../gcc/gcc/cgraph.c:3256
0x69aa45 cgraph_node::expand_thunk(bool, bool)
    ../../gcc/gcc/cgraphunit.c:1604
0x69bd92 cgraph_node::assemble_thunks_and_aliases()
    ../../gcc/gcc/cgraphunit.c:1904
0x69bd65 cgraph_node::assemble_thunks_and_aliases()
    ../../gcc/gcc/cgraphunit.c:1922
0x69bfaf cgraph_node::expand()
    ../../gcc/gcc/cgraphunit.c:2034
0x69d826 expand_all_functions
    ../../gcc/gcc/cgraphunit.c:2107
0x69d826 symbol_table::compile()
    ../../gcc/gcc/cgraphunit.c:2463
0x60cc87 lto_main()
    ../../gcc/gcc/lto/lto.c:3327

Segfaults on symbol _ZThn8_N10xalanc_1_819XercesParserLiaison11resetErrorsEv
demangler.com says the symbol is
non-virtual thunk to xalanc_1_8::XercesParserLiaison::resetErrors()
For this symbol ./-lm.res has lto resolution == PREVAILING_DEF_IRONLY.

Gating cgraph_node::get_untrasnformed_body on lto_file_data seems to
work (also passing bootstrap and test) however I wonder if that's the correct
approach ?

Thanks,
Prathamesh