Finding the critical path in the overlay process

Hello,

I have a problem of internal data memory: I am too short in it.

In order to find the places which mostly affects the memory usage, I would like to find the critical path of the memory allocation usage in the overlay process.
for example, the following code:

f1()
{
  ...
  f2()
  ...
}
f2()
{
  ...
  f3()
  ...
}
f3()
{
  ...
}
f4()
{
  ...
}

I would like to get for the above code the following overlay (memory utilization) information:

f1--------(4) (Bytes)
----------f2----------------(8)
----------------------------f3--------(4)
f4------------------------------(12)

instead of:

f1
  +>>f2

f2
  +>>f3
f3
f4

This way I will be able to find out the functions that are on the critical path of the memory consuming, and focus on the memory usage optimization at the functions that optimizing their memory usage will make a diffrence on the whole program.
In the above example, I will be able to know that it will be better to focus on f1,f2,f3 instead of f4, since f4 is not in the critical path of the memory utilization using the overlay process.

If I can get the information in such a way, I will be happy to know how can I get it.
If not, this may be useful and it is worth thinking of putting this info in the next release of the linker.

Please reply with an answer telling me if this functionality is available in the current linker BL51, v5.12.

Thanks a lot.
.........Amit.