https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87137

Tim Turner <timturnerc at yahoo dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |timturnerc at yahoo dot com

--- Comment #16 from Tim Turner <timturnerc at yahoo dot com> ---
$ ./gdb -nx -q --data-directory=data-directory ~/a.out -ex "set confirm off"
-ex "file -readnow ~/a.out"  http://www-look-4.com/
        Reading symbols from /home/simark/a.out...
        Reading symbols from ~/a.out... https://komiya-dental.com/
        /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:8098: internal-error:
void create_all_comp_units(dwarf2_per_objfile*): Assertion
`per_objfile->per_bfd- http://www.iu-bloomington.com/  >all_comp_units.empty
()' failed. 

    This is a recurring problem that exposes a design issue
https://waytowhatsnext.com/ / in the DWARF
    per-BFD sharing feature.  Things work well when loading a binary with
https://www.mktrade.fi/muottivalmistus
    the same method (with/without index, with/without readnow) twice
http://www.wearelondonmade.com/  in a
    row.  But they don't work so well when loading a binary with different
    methods.  See this previous fix, for example: http://www.jopspeech.com/ 

        efb763a5ea35 ("gdb: check for partial symtab presence in
dwarf2_initialize_objfile") http://joerg.li/ 

    That one handled the case where the first load is normal (uses partial
    symbols) and the second load uses an index. http://connstr.net/ 

    The problem is that when loading an objfile with a method A, we create a 
    dwarf2_per_bfd and some dwarf2_per_cu_data and initialize them with the
http://embermanchester.uk/ 
    data belonging to that method.  When loading another obfile sharing the
    same BFD but with a different method B, it's not
http://www.slipstone.co.uk/  clear how to re-use the
    dwarf2_per_bfd/dwarf2_per_cu_data previously created, because they
    contain the data specific to method A. http://www.logoarts.co.uk/ 

    I think the most sensible fix would be to not share a dwarf2_per_bfd
    between two objfiles loaded with different methods.  That means that two
    objfiles sharing the same BFD http://www.acpirateradio.co.uk/  and loaded
the same way would share a
    dwarf2_per_bfd.  Two objfiles sharing the same BFD but loaded with
    different methods would use two different dwarf2_per_bfd structures.
    http://www.compilatori.com/ 
    However, this isn't a trivial change.  So to fix the known issue quickly
    (including in the gdb 10 branch), this patch just disables all
    dwarf2_per_bfd sharing for objfiles using READNOW.

    Generalize the gdb.base/index-cache-load-twice.exp test to test all
    the possible combinations of loading a file with partial symtabs, index
    and readnow.  Move it to gdb.dwarf2, https://www.webb-dev.co.uk/  since it
really exercises features
    of the DWARF reader.

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