[fpc-pascal] Debug info at runtime?

[Serguei TARASSOV]

I answered myself :) Hope this helps someone.
Here is an example how to get N-2 calling procedure

Warning: code seeking debugging info is slow so be aware to use it in loops.
Make sure to compile with
-gl (not requierd but show file and line numbers info)
-gs (show proc name after address)

var
   i: Longint;
   PrevBP: Pointer;
   CallerFrame, CallerAddr, BP: Pointer;
   CallerName: string = '';
begin
   // get N-2 caller proc name
   BP := get_frame;
   PrevBP := BP - 1;
   i := 0;
   while BP > PrevBP do
   begin
     CallerAddr := get_caller_addr(BP);
     CallerFrame := get_caller_frame(BP);
     if (CallerAddr = nil) or (CallerFrame = nil) then
       break;
     if i = 2 then
     begin
       CallerName := BackTraceStrFunc(CallerAddr);
       break;
     end;
     PrevBP := BP;
     BP := CallerFrame;
     Inc(i);
   end;
...

CallerName should contains something like
   $0043EF0A  TSCRIPTSTEST__TESTPARSER,  line 749 of ScriptsTest.pas

Regards,
Serguei


On 26/05/2015 19:30, Serguei TARASSOV wrote:
> Hi All,
>
> How is possible to get some debug information at runtime?
> Assuming, the program compiled with required debug information/symbols.
>
> I.e. how to get actual call stack state and called procedures names 
> within the procedure or method?
>
> Regards,
> Serguei