FPC 3.2.2 - initialization section - how does the Compiler handle it ?

[ALLIGATOR]

Yes, you are only looking at the compiled content of your module - don't forget that the linker will run next and link your modules to RTL

It is RTL that will call these functions - order.... I don't know what order it will be, most likely sequential, starting with program unit and then sequentially.

Maybe someone more experienced will correct me if I am wrong.

[paule32]

you see? - this is my concerns - how FPC include the unit code and make code from it.
because, on Design time, you write:

uses SysUtils, Classes, Dialogs, ... ;

and my code - you can see, it is linear:

Code: Pascal  [Select][+][-]

1. procedure fpc_initializeunits; [public, alias:'FPC_INITIALIZEUNITS']; compilerproc;
2.     procedure CallProcedure(proc: TProcedure);
3.     begin
4.         if Assigned(proc) then
5.             TProcedure(proc)();
6.     end;
7. var
8.     Index: DWORD;
9. begin
10.     printf('Count Items: %d'#13#10, InitFinalTable.TableCount);
11.     if InitFinalTable.TableCount > 0 then
12.     begin
13.         for Index := 1 to InitFinalTable.TableCount - 1 do
14.         CallProcedure(InitFinalTable.Procs[Index].InitProc);
15.     end;
16. end;
17.  

currently, I have one unit... and it works.
But I will check of two or more units ...

I overthinking too much things.
But the order of .o bject files can be changed - e.g. your order of "uses" directive ...

[ALLIGATOR]

It's pretty easy to determine in person
But you need to use a home-built compiler - because debugging symbols are required (and by the way, I highly recommend that you figure this out because it makes it easier to understand the inner workings of the compiler and RTL in many places). You just need to stand the debugger on the function of module initialization and see the order.
Here, for example, is the order of module initialization for a simple GUI application created by default:

		INITPROC	FINALPROC
pt^.TABLECOUNT = 87
pt^.PROCS[1]		SYSTEM__init	SYSTEM__finalize
pt^.PROCS[2]		nil	OBJPAS__finalize
pt^.PROCS[3]		LNFODWRF__init	LNFODWRF__finalize
pt^.PROCS[4]		FPINTRES__init	nil
pt^.PROCS[5]		nil	WINDIRS__finalize
pt^.PROCS[6]		SYSUTILS__init	SYSUTILS__finalize
pt^.PROCS[7]		TYPINFO__init_implicit	TYPINFO__finalize_implicit
pt^.PROCS[8]		CLASSES__init	CLASSES__finalize
pt^.PROCS[9]		FPCADDS__init	nil
pt^.PROCS[10]		JSONSCANNER__init_implicit	JSONSCANNER__finalize_implicit
pt^.PROCS[11]		VARIANTS__init	VARIANTS__finalize
pt^.PROCS[12]		FPJSON__init	FPJSON__finalize_implicit
pt^.PROCS[13]		JSONPARSER__init	JSONPARSER__finalize
pt^.PROCS[14]		COMMCTRL__init	COMMCTRL__finalize
pt^.PROCS[15]		LAZFILEUTILS__init	LAZFILEUTILS__finalize
pt^.PROCS[16]		FILEUTIL__init_implicit	FILEUTIL__finalize_implicit
pt^.PROCS[17]		DOS__init	nil
pt^.PROCS[18]		LCONVENCODING__init_implicit	LCONVENCODING__finalize_implicit
pt^.PROCS[19]		nil	LAZLOGGERBASE__finalize
pt^.PROCS[20]		AVL_TREE__init	AVL_TREE__finalize
pt^.PROCS[21]		STRINGHASHLIST__init	nil
pt^.PROCS[22]		TRANSLATIONS__init_implicit	TRANSLATIONS__finalize_implicit
pt^.PROCS[23]		LAZUTF8__init	LAZUTF8__finalize
pt^.PROCS[24]		FPIMAGE__init	FPIMAGE__finalize
pt^.PROCS[25]		nil	LAZTRACER__finalize
pt^.PROCS[26]		SYSTEM.UITYPES__init	nil
pt^.PROCS[27]		GRAPHTYPE__init	nil
pt^.PROCS[28]		LCLTYPE__init_implicit	LCLTYPE__finalize_implicit
pt^.PROCS[29]		LCLPROC__init	LCLPROC__finalize
pt^.PROCS[30]		LCLPLATFORMDEF__init_implicit	LCLPLATFORMDEF__finalize_implicit
pt^.PROCS[31]		FPIMGCMN__init	nil
pt^.PROCS[32]		FPREADBMP__init	nil
pt^.PROCS[33]		FPWRITEBMP__init	nil
pt^.PROCS[34]		FPREADPNG__init	nil
pt^.PROCS[35]		FPWRITEPNG__init	nil
pt^.PROCS[36]		FPCOLORSPACE__init	FPCOLORSPACE__finalize_implicit
pt^.PROCS[37]		FPREADTIFF__init	nil
pt^.PROCS[38]		FPWRITETIFF__init	nil
pt^.PROCS[39]		LCLVERSION__init	nil
pt^.PROCS[40]		FPCANVAS__init_implicit	FPCANVAS__finalize_implicit
pt^.PROCS[41]		FPREADPNM__init	nil
pt^.PROCS[42]		FPWRITEPNM__init	nil
pt^.PROCS[43]		FPREADJPEG__init	nil
pt^.PROCS[44]		FPWRITEJPEG__init	nil
pt^.PROCS[45]		FPREADGIF__init	nil
pt^.PROCS[46]		LRESOURCES__init	LRESOURCES__finalize
pt^.PROCS[47]		SYSTEM.TIMESPAN__init_implicit	SYSTEM.TIMESPAN__finalize_implicit
pt^.PROCS[48]		LCLINTF__init	LCLINTF__finalize
pt^.PROCS[49]		GRAPHICS__init	GRAPHICS__finalize
pt^.PROCS[50]		INTFGRAPHICS__init	nil
pt^.PROCS[51]		THEMES__init_implicit	THEMES__finalize_implicit
pt^.PROCS[52]		INTERFACEBASE__init	nil
pt^.PROCS[53]		MULTIMON__init	nil
pt^.PROCS[54]		UXTHEME__init	UXTHEME__finalize
pt^.PROCS[55]		DWMAPI__init	DWMAPI__finalize
pt^.PROCS[56]		UNICODEDATA__init_implicit	UNICODEDATA__finalize_implicit
pt^.PROCS[57]		FPPIXLCANV__init_implicit	FPPIXLCANV__finalize_implicit
pt^.PROCS[58]		nil	WSLCLCLASSES__finalize
pt^.PROCS[59]		ACTNLIST__init	nil
pt^.PROCS[60]		nil	WSMENUS__finalize
pt^.PROCS[61]		CLIPBRD__init	CLIPBRD__finalize
pt^.PROCS[62]		FORMS__init	FORMS__finalize
pt^.PROCS[63]		MENUS__init_implicit	MENUS__finalize_implicit
pt^.PROCS[64]		IMGLIST__init	nil
pt^.PROCS[65]		RTTIUTILS__init_implicit	RTTIUTILS__finalize_implicit
pt^.PROCS[66]		CONTROLS__init	CONTROLS__finalize
pt^.PROCS[67]		BUTTONS__init_implicit	BUTTONS__finalize_implicit
pt^.PROCS[68]		EXTCTRLS__init	EXTCTRLS__finalize_implicit
pt^.PROCS[69]		DIALOGRES__init	DIALOGRES__finalize_implicit
pt^.PROCS[70]		COMCTRLS__init_implicit	COMCTRLS__finalize_implicit
pt^.PROCS[71]		DATEUTILS__init_implicit	DATEUTILS__finalize_implicit
pt^.PROCS[72]		nil	TASKDLGEMULATION__finalize
pt^.PROCS[73]		DIALOGS__init	DIALOGS__finalize
pt^.PROCS[74]		WIN32EXTRA__init	WIN32EXTRA__finalize
pt^.PROCS[75]		WIN32PROC__init	WIN32PROC__finalize
pt^.PROCS[76]		CALCFORM__init_implicit	CALCFORM__finalize_implicit
pt^.PROCS[77]		HTMLDEFS__init_implicit	HTMLDEFS__finalize_implicit
pt^.PROCS[78]		MASKEDIT__init	nil
pt^.PROCS[79]		LAZFILECACHE__init	nil
pt^.PROCS[80]		nil	LAZ2_XMLUTILS__finalize
pt^.PROCS[81]		LAZ2_DOM__init_implicit	LAZ2_DOM__finalize_implicit
pt^.PROCS[82]		URIPARSER__init_implicit	URIPARSER__finalize_implicit
pt^.PROCS[83]		LAZ2_XMLREAD__init	LAZ2_XMLREAD__finalize_implicit
pt^.PROCS[84]		SHELLCTRLS__init_implicit	SHELLCTRLS__finalize_implicit
pt^.PROCS[85]		WIN32WSDIALOGS__init	WIN32WSDIALOGS__finalize_implicit
pt^.PROCS[86]		WIN32INT__init	WIN32INT__finalize
pt^.PROCS[87]		INTERFACES__init	INTERFACES__finalize

[ALLIGATOR]

Although that may not be quite the answer you're expecting..... it's a fait accompli of how modules will be loaded, but it doesn't answer the question - how is it regulated... but for that you need to dive deeper and analyze it.

[paule32]

ok, what a fat list 
what debugger do you prefer - Laz or Gdb ?
I am a nerd in using debuggers.
But when I have the right one, it will be okay.

[ALLIGATOR]

I don't know much about debuggers either, but so far all my needs are covered by FpDebud
For the very advanced - there is a new promising solution of professional level (IMHO) - CPU-View, but I haven't tested it yet:
https://forum.lazarus.freepascal.org/index.php/topic,68962.0.html

[PascalDragon]

I overthinking too much things.
But the order of .o bject files can be changed - e.g. your order of "uses" directive ...

The order of the object files is irrelevant. The compiler generates the INITFINAL table when a program or library is created and the entry point in SysInit passes this table towards the entry point of the RTL which can then access it using InitFinalTable.