[Dwarf-Discuss] Interaction between aranges and unit proposals

Mark Wielaard mjw at redhat.com
Wed Apr 2 04:26:30 PDT 2014


On Wed, 2014-04-02 at 12:18 +0200, Mark Wielaard wrote:
> Maybe the solution is to have an alternate .debug_aranges header just
> for empty units that is as small as possible? Or reuse the existing
> header fields as "flag"? Maybe have the proposed header format of issue
> 100430.1 but if address_size and segment_size are both zero then no
> address range descriptor will be added and that headers signals a
> "no-address" unit?

I forgot, there is another "solution". You could try to be not as
pedantically correct as GDB is following the DWARF standard. elfutils
tools like eu-addr2line and the libdwfl library functions to map
addresses to debug lines or DIEs for example just assume aranges isn't
an optional thing and that it will always be complete. That makes the
elfutils tools a lot faster than GDB, but obviously not as universal
(they just fail to match if no aranges are found). For this to work for
other tools however the indexes should be "upgraded" from quality of
service to mandatory.

Cheers,

Mark




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