[avr-gcc-list] Stack usage profiling for function calls.

[Mattias Svensson]

I made this post earlier and got one reply that said that for mips-gcc 
the option -mstats gives the output I am looking for. But it is not 
applicable to avr-gcc.

It is important to know how much stack is used with small RAM and no mem 
protection.
I don't know if I am alone with this need?

Since gcc tracks the prologue and epiloge sizes for each function 
(output to the assembler listing) it would not be to hard to make a 
summary of the number of "push" calls for each function. In fact in most 
cases the prologue size is the same as the number of "push" calls.

I have not made the nosedive into the GCC sources yet, but it would 
probaly not be to complicated to make a summary for each function e.g. 
at the bottom of the assembler listing.

Any suggestions on the best way to do it?

Maybe a look at the mips-gcc code would be a good idea...

The optimal tool would take a function and recurively run through each 
sub function and sum the stack usage and report the deepest usage. This 
  of course requires the code to be deterministic, not depending on 
variables or hw events. But correctly used it would be a good tool.

/M Svensson

-------- Original Message --------
Subject: [avr-gcc-list] Stack usage profiling for function calls.
Date: Thu, 20 Mar 2003 10:26:43 +0100
From: Mattias Svensson <address@hidden>
To: address@hidden

I Wonder if there is any tool available that takes a function written in
C and traces the stack usage of subsequent calls to other functions.

Today I read the assembler listing file ".list" output from avr-gcc and
trace how many registers are pushed onto the stack for each function, it
works but is kind of time consuming...

Maybe I have missed some nice switch for avr-gcc that generates what I want.

It is also possible to make a mem dump and see how deep the stack has
grown since all RAM is zeroed at init. But it is not accurate enough,
some worst case scenarios are easily missed.

Regards:
M Svensson.


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