gcc 4.1 Options for Maximum Debugging (also ecos synth).

[John Carter <john dot carter at tait dot co dot nz>]

We have two builds. One that runs on our embedded target and has -Os and 
another that runs on our Linux desktop machines and is just for running 
unit tests and debugging.

Current the desktop build is built -O0, but I suspect that isn't really 
what I want.

-O0 means "no optimization".

In practice is means "be a dumb stupid compiler" and don't...
 * Don't do enough work to make the assembler readable, clutter it with
   lead in / lead out code for each fragment.
 * Don't do enough data flow analysis to give initialized variables
   warnings.
 * Don't do any global analysis to detect bad code.

So what I want is..
 * Assembler that is easy to read and correlates well with the source.
 * In depth data flow / static analysis to give good warnings.
 * Stack and bounds checking to the maximum. (Hey, the desktop PC is about
   a 1000 times faster than the embedded target and has no memory / real
   time constraints.)

My current guess as to the gcc settings I want are...
 -O1  -fno-delayed-branch -fno-guess-branch-probability \
 -fno-cprop-registers -fno-loop-optimize -funit-at-a-time

I tried -fstack-protector but it then seemed to want a bunch of extra 
libraries.

Question 1:
  Which optimization / -f options on gcc 4.1 would you recommend for
  maximum warnings / analysis / debuggability? (Assuming all appropriate
  -W options are switched on already...)

Question 2:
  Has anybody got -fstack-protector working with ECos synthetic platform?


John Carter                             Phone : (64)(3) 358 6639
Tait Electronics                        Fax   : (64)(3) 359 4632
PO Box 1645 Christchurch                Email : john.carter@tait.co.nz
New Zealand

Carter's Clarification of Murphy's Law.

"Things only ever go right so that they may go more spectacularly wrong later."

> From this principle, all of life and physics may be deduced.