Re: [PATCH][gdb/symtab] Redo "Fix assert in set_length"

[Tom Tromey <tom@tromey.com>]

>>>>> "Tom" == Tom de Vries via Gdb-patches <gdb-patches@sourceware.org> writes:

Tom> The fix is to not use the CU table in a .debug_names section to construct
Tom> all_comp_units, but instead use create_all_comp_units, and then verify the CU
Tom> table from .debug_names.  This also fixes PR25969, so remove the KFAIL.

Note that create_all_comp_units was apparently renamed, so this text
should be changed.

Part of the point of the indices is to avoid reading .debug_info until
needed -- so scanning it should not be necessary.  I assume this change
would cause a performance drop.

Checking whether performance suffers would be interesting.
If it doesn't, I'd be more inclined to do this.

Tom> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29572

In this one I see the comment:

    This happens fine for CUs, but in this case it's a PU.

Does .debug_names even work with partial units?  I thought there was
some hole in this area.  Maybe it is just "dwz -m" that can't work with
.debug_names?  I don't recall any more.

Tom> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=25969

I'm not sure I understand this one, but it says:

    AFAIU, to fix this, we'll have to do a top-level scan of the CUs,
    and build partial symbols for CUs are not contained in any index.

I think if the index is incomplete, and gdb can detect that, then it
should simply be discarded and a full scan done.  Trying to use both
.debug_names and a partial cooked index is going to make everything more
complicated for, IMO, very little gain.

Tom