Re: [RFA/RFC] Add dump and load command to process record and replay

[Michael Snyder <msnyder@vmware.com>]

Eli Zaretskii wrote:
>> Date: Sat, 29 Aug 2009 11:29:04 -0700
>> From: Michael Snyder <msnyder@vmware.com>
>> CC: Hui Zhu <teawater@gmail.com>, 
>>  "gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
>>
>>> "A core file"? you didn't really mean that, did you?
>> Yep!  That was my suggestion.  We use a core file to capture the
>> state at the beginning of the recording, then add an extra bfd
>> section to the corefile and write the recording log into that.
> 
> What is this useful for?

I'm replying twice, just in case one of my explanations happens
to 'click' better than the other.

The record-log that process-record keeps in memory records only
changes in state -- it does not contain a 'snapshot' of the entire
state at any point (eg. at the beginning of the session).  Therefore
you can't use it unles you can first duplicate the starting state.

Hui's approach was to first save a corefile, to record the starting
state, and then save the changes file separately.  A brilliant idea,
but it has a drawback -- since they are separate files, there is no
way to protect users against loading a start state from one program
and a change set from a completely different program.