Re: [PATCH 2/4] Don't erase empty indices in DWARF reader

[Tom Tromey <tromey@adacore.com>]

>>>>> "Andrew" == Andrew Burgess <aburgess@redhat.com> writes:

>> The DWARF reader has some code to remove empty indices.  However, I
>> think this code has been obsolete since some earlier changes to
>> parallel_for_each.  This patch removes this code.

Andrew> Would NULL entries cause problems later in GDB?  Would it be worth
Andrew> replacing this code with an assert that there are no NULL entries?  Or
Andrew> would an attempt to create a NULL entry trigger an assert/error
Andrew> elsewhere?

If it could happen, it would cause a crash when doing any kind of
lookup, because cooked_index_vector iterates over the indices and calls
methods on each one.

Andrew> Or maybe the cost of iterating over the list is what you want to remove
Andrew> here?  In which case, could we guard an assert in '#ifdef DEVELOPER'?

I don't think there's any performance issue, as the size of the array is
normally just the number of cores on the user machine.

It's more that this is a leftover and can't happen any more, due to the
previous patch.  It seems to me that the contract of parallel_for_each
should be that, if it returns results (i.e., not void), then each entry
in the result must be the result of actually calling the callback --
i.e., not some default.

That said, it's also fine to drop this patch.

Tom