Re: [PATCH] dwarf: Make sect_offset 64-bits

[Pedro Alves <palves@redhat.com>]

On 02/20/2018 04:38 PM, Simon Marchi wrote:
> On 2018-01-28 12:26 PM, Simon Marchi wrote:
>> Does anybody have an opinion about this?  It would be nice to unbreak
>> the "default" build with clang (i.e. without passing special -Wno-error=
>> flags).
>>
>> Here's a version rebased on today's master.
> 
> Ping.
> 

Does this change the type of any field of the structures that form the
indexes?  I.e., does it affect binary compatibility there?  I.e.,
can you save a gdb index with pre-patch gdb, and load it back in
post-patch gdb.  Likewise viceversa.  Also DWARF5 indexes.

Also, just for the record, can we assume that this doesn't increase
memory usage considerably when debugging bigger programs?  I assume that
this will create some padding holes in some structures and that we can
probably win back the memory by just changing order of some fields
for better packing.

Offhand, I know about code in dwarf2read.c that assumes that offset_type
is 32-bit for both of the reasons above -- memory usage (e.g.,
struct name_component), and also as type used in indexes.
I'm not seeing anything for sect_offset, but can you double check?

Thanks,
Pedro Alves