1. Oracle function call list

If you want to see what other functions a given function calls in software, you can disassemble the function. Inspired by Dennis Yurichev's Oracle function call list, which enumerates all functions in the modules inside $ORACLE_HOME/lib/libserver.a, I generate the function call list from $ORACLE_HOME/bin/oracle, with the script described in the Appendix. The result is

apadrv
      1 apaqbdDescendents
      1 chnacc
      5 dbgdChkEventIntV
      5 dbgtCtrl_intEvalCtrlEvent
      1 dbgtCtrl_intEvalTraceFilters
      1 dbgtGrpB_int
      1 dbgtGrpE_int
      1 dbgtWrf_int
      1 dbkdChkEventRdbmsErr
...

To-do: search of my function call list result file.

2. Event check list

Unfortunately, the above function call list does not show the arguments passed to each function. One of the most useful functions in Oracle is dbkdChkEventRdbmsErr (probably DB kernel debug check event of RDBMS error), which requires one argument, the RDBMS event number. With a little more effort, we can find what event a given function checks by extracting the argument passed to the said function. The result is

ELMAINT: 37393
GELErase: 37397
Java_oracle_xdb_spi_XDBNamingEnumeration_closeKprbNative: 31150
...
apadrv: 10507
apaqba: 10137
atbadd: 10851
atbadd: 12498
atbadd: 12498
...

$ oerr ora 10507
10507, 00000, "Trace bind equivalence logic"
// *Cause:
// *Action:

The above output also shows multiple lines for one function atbadd. My program sequentially generates these lines and show the same function name repeatedly, which makes the output of a simple grep command easier to read. In the case of atbadd, it checks RDBMS events 10851, 12498 and 12498 again.

For your convenience, you can search my function-event result file given a function name or an event number:

The search result is equivalent to a grep command run against your own result file, e.g. a search for event 10035 ("Write parse failures to alert log file"):

$ grep 10035 oracle_func_evt.txt
kksSetBindType: 10035
...
kksfbc: 10035
...

3. Summary

Next time you see an Oracle function in the call stack in a trace file, or in the output of pstack pid, and wonder what it does, you can either disassemble it or check your event check list file (see Appendix). But if you want to see what other functions may call this function, the latter is the only option. This of course won't really tell you exactly what the function does, but at least you have one more tool to aid the guesswork.^note1

The second part of the work, event check list, is useful in that many events are documented. If a given function happens to check for an RDBMS event, it greatly helps decipher what this function does. In addition, if you're interested in a reverse search, i.e. finding all the functions that check for a specific event, you can do so as well.

[Update 2017-02] If you just want to run a quick check on a function for possible events associated with it, here's the command:
gdb -n -q -ex "disas functionname" -ex q oracle | grep -B2 dbkdChkEventRdbmsErr | perl -nle "print hex(\$1) if /x([0-9a-f]+),\%edi$/" | uniq
Or equivalently (credit to Franck Pachot):
gdb oracle <<<"disas functionname" | awk --non-decimal-data '/mov .*,%edi$/{gsub(/[$,]/," ");a=$4}/EventRdbmsErr/{printf "%d\n", a}' | sort -u

nm $ORACLE_HOME/bin/oracle | awk '/ [Tt] / {print $3}' | egrep -v '\.|rot13|_etext|__init_array_' > oracle.Txt.nm #extract global and local text symbols

for i in $(<oracle.Txt.nm); do
 echo $i
 gdb -n -q -ex "disas $i" -ex q $ORACLE_HOME/bin/oracle | perl -nle 'print $1 if /(?:call|jmp)q .+ <([^+>]+)[+\d>]+$/' | sort | uniq -c | grep -w -v "$i$"
done > oracle_func.txt

mkfifo in out
gdb -n -q $ORACLE_HOME/bin/oracle <in >out &
exec 3> in 4< out
for i in $(<oracle.Txt.nm); do
 echo $i
 echo "disas $i" >&3
 while read var <&4; do
  echo $var
  [[ $var =~ "End of assembler dump" ]] && break
 done | perl -nle 'print $1 if /(?:call|jmp)q .+ <([^+>]+)[+\d>]+$/' | sort | uniq -c | grep -w -v "$i$"
done > oracle_func.txt

To find out what event a function checks, the argument to function dbkdChkEventRdbmsErr must be extracted. The argument can be found in the direct output of disas command in gdb.

(gdb) disas apadrv
Dump of assembler code for function apadrv:
...
   0x0000000002a05394 <+6580>:  mov    $0x290b,%edi
   0x0000000002a05399 <+6585>:  callq  0xcc13110 <dbkdChkEventRdbmsErr>

In order to find the events a given function checks, the following code can be run.

for i in $(<oracle.Txt.nm); do
 gdb -n -q -ex "disas $i" -ex q $ORACLE_HOME/bin/oracle | grep -B2 dbkdChkEventRdbmsErr | perl -nle "print '${i}: '.hex(\$1) if /x([0-9a-f]+),\%edi$/"
done > oracle_func_evt.txt

mkfifo in out
gdb -n -q $ORACLE_HOME/bin/oracle <in >out &
exec 3> in 4< out
for i in $(<oracle.Txt.nm); do
 #echo $i >> progress.log #tracking progress helps restart from where it fails for any reason
 echo "disas $i" >&3
 while read var <&4; do
  echo $var
  [[ $var =~ "End of assembler dump" ]] && break
 done | grep -B2 dbkdChkEventRdbmsErr | perl -nle "print '${i}: '.hex(\$1) if /x([0-9a-f]+),\%edi$/"
done > oracle_func_evt.txt

Notes

[note1] Oracle used to publish the document ORA-600 Lookup Error Categories (Doc ID 175982.1), which you can still find on the Internet. Many function prefixes are listed in the document.
[note2] I exclude the symbols with dot in the names to simplify the work. If you include them, you have to put them in single quotes when passing to the gdb command, e.g., disas '__intel_new_proc_init.A'. For the 12.1.0.2 oracle binary, there're 58 of them, which all seem to be interanl Intel CPU specific functions, including those like __svml_cbrt2_mask.A related to short vector math library.

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