Profiling Ada binaries

["Markus Schöpflin" <no.spam@spam.spam>]

Dear list,

I realize that the following question is rather vague, but I hope that perhaps 
someone can give me some advice on how to proceed, or maybe has already 
experienced similar issues.

I am trying to profile code generated by Gnat using Gprof. For this I add -pg 
to the compilation and link switches, turn down optimization to -O1 and 
disable inlining of functions only called once 
(-fno-inline-functions-called-once).

The result obtained when running gprof to generate the report from the 
profiling data gathered during running the executable is rather strange, as 
the report suggests that e.g. elaboration functions of compilation units are 
called countless times, which of course most likely isn't true.

To illustrate, here are the first few lines of a flat profile:

Flat profile:

Each sample counts as 0.01 seconds.
   %   cumulative   self              self     total
  time   seconds   seconds    calls   s/call   s/call  name
   4.66      4.91     4.91      429     0.01     0.01  foo1
   4.41      9.55     4.64 162635540     0.00     0.00  bar___elabs
   3.99     13.76     4.21   515639     0.00     0.00  foo2

As one can see, the second line suggests that the elaboration for the spec of 
the package bar is called 162635540 times. Looking at the call graph of 
bar___elabs shows:

                 0.00    0.00       1/162635540     adainit [92]
                 0.00    0.00      33/162635540 
standard_math__float_32_elementary__arccosX [2249]
                 0.00    0.00    1461/162635540 
standard_math__float_32_elementary__arcsinX [1099]
                 0.00    0.00  108848/162635540 
standard_math__float_64_elementary__arctanX [1573]
                 0.00    0.00  109380/162635540 
standard_math__float_64_elementary__sinX [1572]
                 0.00    0.00  163937/162635540 
standard_math__float_64_elementary__cosX [687]
                 0.01    0.00  515639/162635540 
standard_math__float_32_elementary__OexponX [609]
                 0.03    0.00 1029874/162635540 
standard_math__float_32_elementary__tanX [346]
                 0.04    0.00 1358089/162635540 
standard_math__float_64_elementary__sqrtX [454]
                 0.04    0.00 1543778/162635540 
standard_math__float_32_elementary__logX [558]
                 0.50    0.00 17564360/162635540 
standard_math__float_32_elementary__expX [93]
                 0.56    0.00 19681964/162635540 
standard_math__float_32_elementary__arctanX [56]
                 0.79    0.00 27790226/162635540 
standard_math__float_32_elementary__cosX [51]
                 0.82    0.00 28730603/162635540 
standard_math__float_32_elementary__sinX [49]
                 1.83    0.00 64037347/162635540 
standard_math__float_32_elementary__sqrtX [45]
[33]     4.4    4.64    0.00 162635540         bar___elabs [33]

There is one legit call from adainit, all other reported calls are most likely 
incorrect. The many calls to standard math functions most likely are correct, 
they just don't call bar___elabs.

Did anybody encounter such anomalies before? Is there a way to get correct 
profiling information for Ada binaries generated by Gnat? Different compiler 
flags maybe? Or using a different profiling tool altogether?

TIA,
Markus