> On Oct 13, 2016, at 2:24 AM, Giusti, Valentina via lldb-dev 
> <lldb-dev@lists.llvm.org> wrote:
> Hello all,
> Background: 
> Intel CPUs that support MPX have a limited number of bound registers. For any 
> program that has more objects than fit into these registers, the bounds must 
> be kept elsewhere. For this purpose, Bounds Tables (BT) are stored in 
> application memory: for each pointer there is a bound table entry with lower 
> bound, upper bound, check pointer value.
> It would be convenient for the user to be able to access the BT and possibly 
> also manipulate it, through commands like: 'set/show mpx-bounds 
> <pointer_name> <lower-bound-value> <upper-bound-value>'.
> Is there a way to add customized commands for vendor features, such as this 
> one?
> I have seen that CommandObjectCommands has a class to add commands 
> interpreted by command interpreter scripts and an interface for command 
> aliases, so I wonder if it would make sense to add something else for vendor 
> commands. For example, I could create a new class CommandObjectVendor that 
> allows vendors to create their own specific commands. In my case, for the MPX 
> bound table, the commands could be:
>       intel show mpx-bounds <pointer_name> <lower-bound-value> 
> <upper-bound-value>
>       intel set mpx-bounds  <pointer_name> <lower-bound-value> 
> <upper-bound-value>
> Thanks in advance for your help,

You can install new python commands that can do the job to work out the 



You can basically install a new "intel" command and parse all of the options 
"show mpx-bounds ..." or "set mpx-bounds ..." from within this new command. You 
can use the public LLDB API to look through the process and do things. Let me 
know if you need any help with this. There is also a API to add custom commands 
from C++ plug-ins. Enrico Granata did this work and can answer more questions 
on that. Either way, both commands (python and C++ plug-ins) have access to the 
public API for LLDB, so the code you will write will use the same API. So I 
would stick with python for now to get things working.

Some questions for you:
- How do plan on detecting that you have an intel processor? 
- Do you need access to any process registers? If so, are these registers 
thread specific? Are these registers available currently on linux and MacOS?
- How do you locate the BT? (or do you even need to?). Is there symbol? Can you 
extract all values in the bounds table once you locate it?

Let me know if you have any questions,

Greg Clayton

> - V.
> Intel Deutschland GmbH
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