Re: [RFC] choose symbol from given block's objfile first.

[Pedro Alves <palves@redhat.com>]

On 05/07/2012 11:43 PM, Joel Brobecker wrote:

> Hello,
> 
> This patch is a prototype for an issue very briefly discussed on IRC.
> Quick description of the problem:
> 
>     We have a program which is linked against two shared libraries.
>     Both libraries define a global symbol with the same name. In my
>     example, I used an int called this_library_version.  When trying
>     to print the value of this global, GDB just randomly selects
>     the first one it finds, and I couldn't find a way (that worked)
>     which allowed me to print the value of the other global.
> 
> The idea behind this patch is to reduce a little bit the randomness.
> If one is debugging code inside one of the shared libraries, then
> the variable that the user probably wants is the one that is defined
> inside that shared library.


+1.

> 
> It's a bit of a poor man's answer to this issue. On the one hand,
> you do not always get the same symbol every single time. But on
> the other hand, the selection process is implicit and not always
> work-able for the user.  Eventually, what we thought we needed was
> extend the expression parser to allow the user to qualify his
> variable name with the name of the objfile, such as for instance:
> 
>         (gdb) print libsomething.so::this_library_version
> 

> This is something that can be done in parallel to this effort.

Yeah... It's one of those features that I think if we added together
all the time people have spent saying IWBN to have it, it'd sum up
to enough to implement it.  :-)

<pedantic mode>
Still, this wouldn't solve the case of loading the same
library twice...  Which symbol would you print?
</pedantic mode>

-- 
Pedro Alves