Re: Should we be able to read simulator memory immediately after a "load" command?

[Michael Snyder <msnyder@vmware.com>]

Kevin Buettner wrote:
> In the course of debugging a program in which the LMA and VMA of
> certain segments differ, we've noticed that simulator memory cannot be
> read immediately after a issuing a "load" command.  One needs to "run"
> the program first in order to be able to access simulator memory.
> 
> In our debugging scenario, the fact that the LMA differs from the VMA
> is only significant in that when they're the same, you tend to get the
> expected results when attempting to read memory immediately after the
> "load" due to the fact that GDB does memory fetches using the exec
> file.   When the LMA and VMA are different, the exec file provides
> access to memory at the VMA addresses, but not at LMA addresses.
> When using the simulator (or a remote target), I would expect to
> be able to read memory located at a valid LMA addresss.  Memory at
> at a VMA address may or may not be available yet; it will most likely be
> initialized early on during execution of the program.
> 
> The code responsible for disallowing access to simulator memory after
> a "load", but before a "run" appears as follows in
> gdbsim_xfer_inferior_memory():
> 
>   /* If no program is running yet, then ignore the simulator for
>      memory.  Pass the request down to the next target, hopefully
>      an exec file.  */
>   if (!target_has_execution)
>     return 0;
> 
> This code was added in a patch from 2006.  See:
> 
>     http://sourceware.org/ml/gdb-patches/2006-10/msg00042.html
> 
> In that posting, Daniel provides a good rationale for that patch as a
> whole, but I did not see any discussion of the portion affecting
> gdbsim_xfer_inferior_memory().
> 
> So, the obvious question... Is there any good reason to prohibit
> access to the simulator's memory immediately after a load?
> 
> (If not, I'll post a patch removing that restriction...)

Hmm, should we substitute "target_has_memory"?

Is that set to TRUE after a load?