profiling on ARM

profiling on ARM

[jeroen dobbelaere]

Hi,

I'm trying to get profiling working on an ARM platform (arm-linux) and
I've observed following behavior :

(glibc-2.2.5 compiled with gcc-3.0.4;
  testprogram with gcc-3.0.4 and gcc-3.2) :

- using no optimizations and static compilation produces a
   binary that generates a 'gmon.out' file containing useful data.
   (ex. gcc -static -g -pg testfile.c)
- enabling optimizations and static compilation produces a
   binary that generates a 'gmon.out' file, but that contains no call graph
   information
   (ex. gcc -static -g -pg -O3 testfile.c)

    debugging the code shows that the problem is due to frame pointers being
    optimized away.
    adding '-fno-omit-frame-pointer' resolves this problem.

    QUESTION : shouldn't this been taken care of automatically when providing '-pg',
               or should the profiling still work without frame pointers.

- using 'shared libraries', no 'gmon.out' is created. It seems that the
   initalisation code for profile monitoring ('moncontrol') is never called.
   Any idea where this should be told to the program ?


The same tests on an i686 platform produces valid output for each of those cases...

Greetings,
-- 
Jeroen Dobbelaere
Embedded Software Engineer

ACUNIA Embedded Solutions
http://www.acunia.com/aes