How to extract the Windows PE file function call graph (FCG)? And why I get FCG is very strange?-CodePudding

Now you need to call each PE file FCG, already have a solution is to call IDA batch mode and IDAPython script analysis and get the call graph, CMD command and the script is as follows:

 
# gen_fcg. Py 
# - * - coding: utf-8 - * - 
# python 2 
The import pickled 
The import idaapi 
The import of logging 
The import sys 
Logging. BasicConfig (level=logging. The INFO format='% (asctime) s - % (filename) s/line: % d (lineno) - % (levelname) s - % (the message) s') 

Def gen (out_name) : 
Text_addr=ScreenEA () 
FCG=dict () 
For callee_addr Functions provides in () : 
Callee_name=GetFunctionName (callee_addr) 

For caller_addr in CodeRefsTo (callee_addr, 0) : 
Caller_name=GetFunctionName (caller_addr) 
Logging. The info (callee_name + '-' + caller_name) 
FCG [caller_name]=FCG. Get (caller_name, set ()) 
FCG [caller_name]. Add (callee_name) 
Pickle. Dump (FCG, open (out_name, 'w')) 
Print FCG 

If __name__=="__main__ ': 
Logging. The info (' sys. Argv '+ STR (sys. Argv)) 
Idaapi. AutoWait () 
Logging. The info (' start analyse... ') 
Gen (' D: \ \ Lab \ \ data_win \ \ FCG \ \ FCG PKL ') 

Idc. Exit (0)

Command line to invoke the command, for PE file parsing:

 % % IDAQ_PATH - l./analysis. The log - c - A - s./gen_cfg py./CRACKME. EXE

Environment: IDA6.8, Windows 10, python2.7

But this method of FCG figure, remove the sub opening method (IDA identification code written by a programmer), for a lot of files, the rest API function of system is obtained only three: [' DialogFunc ', 'start', 'StartAddress], the result of the proportion of the total file is close to 50%, is this normal?
If it is not normal, what other ways to get a PE file FCG figure?