Pascal JIT

[tihory]

Hi,

I'm interested to implement a Pascal JIT linker, so I implemented a COFF 64bit linker and link object files generated by FPC trunk then link them with DLL dependencies like "kernel32.dll" and "user32.dll".

Project source code is available at https://github.com/tihorygit/TheLinker.

Now I have a problem with linking FPC compiler functions like "fpc_initializeunits". After files linked together, some of these functions point to an invalid location in object memory and cause an access violation exception.

I read Pascal TInternalLinker code but didn't find any solution, is anyone experience with linkers to help me or have a solution?

[Leledumbo]

The function is defined in rtl/inc/system.inc and is included in every system unit implementation:

Code: Bash  [Select][+][-]

1. $ grep -ir fpc_initializeunits *
2. inc/compproc.inc:procedure fpc_InitializeUnits; compilerproc;
3. inc/system.inc:procedure fpc_InitializeUnits;[public,alias:'FPC_INITIALIZEUNITS']; compilerproc;
4. inc/system.inc:procedure internal_initializeunits; external name 'FPC_INITIALIZEUNITS';
5. java/jsystem.inc:procedure fpc_InitializeUnits;[public,alias:'FPC_INITIALIZEUNITS']; compilerproc;
6. java/jsystem.inc:procedure internal_initializeunits; external name 'FPC_INITIALIZEUNITS';
7. java/jcompproc.inc:procedure fpc_InitializeUnits; compilerproc;
8. $ grep -ir system.inc *
9. aix/system.pp:{$I system.inc}
10. amiga/system.pp:{$I system.inc}
11. aros/system.pp:{$I system.inc}
12. atari/system.pp:    {$i system.inc}
13. beos/system.pp:{$I system.inc}
14. bsd/system.pp:{$I system.inc}
15. embedded/system.pp:{$I system.inc}
16. emx/system.pas:{$I system.inc}
17. fpmake.pp:          AddInclude('system.inc',AllUnixOSes);
18. freertos/system.pp:{$I system.inc}
19. gba/system.pp:{$i system.inc}
20. go32v2/system.pp:{$I system.inc}
21. haiku/system.pp:{$I system.inc}
22. inc/readme:system.inc      OS and Processor independent implementation part of system unit.
23. java/system.pp:{$i jsystem.inc}
24. linux/system.pp:{$I system.inc}
25. macos/system.pp:{$I system.inc}
26. morphos/system.pp:{$I system.inc}
27. msdos/system.pp:{$I system.inc}
28. msxdos/system.pp:{$I system.inc}
29. nativent/system.pp:{$I system.inc}
30. nds/system.pp:{$i system.inc}
31. netware/system.pp:{$I system.inc}
32. netwlibc/system.pp:{$I system.inc}
33. os2/system.pas:{$I system.inc}
34. palmos/system.pp:{$i system.inc}
35. qnx/system.pp:{$I system.inc}
36. sinclairql/system.pp:  {$i system.inc}
37. solaris/system.pp:{$I system.inc}
38. symbian/system.pp:{$I system.inc}
39. wasi/system.pp:{$I system.inc}
40. watcom/system.pp:{$include system.inc}
41. wii/system.pp:{$i system.inc}
42. win16/system.pp:{$I system.inc}
43. win32/system.pp:{$I system.inc}
44. win64/system.pp:{$I system.inc}
45. wince/system.pp:{$I system.inc}
46. zxspectrum/system.pp:{$I system.inc}
47.  

do notice that it's exported ALL CAPS as FPC_INITIALIZEUNITS, bet your linker is case sensitive, right?

[PascalDragon]

do notice that it's exported ALL CAPS as FPC_INITIALIZEUNITS, bet your linker is case sensitive, right?

Linkers are supposed to be. The compilerproc directives leads to the compiler generating a lowercase mangled name (here fpc_initializeunits) which can't be accessed using an external directive, which is why an all uppercase alias (FPC_INITIALIZEUNITS) is added.

[tihory]

do notice that it's exported ALL CAPS as FPC_INITIALIZEUNITS, bet your linker is case sensitive, right?

Due to the "dumpbin" output, the "FPC_INITIALIZEUNITS" and "fpc_initializeunits" point to the same address in object memory.

Maybe this problem occurs because FPC uses a custom linking script and the "FPC_INITIALIZEUNITS" searches for specific addresses in memory depends on the linking script.

[PascalDragon]

do notice that it's exported ALL CAPS as FPC_INITIALIZEUNITS, bet your linker is case sensitive, right?

Due to the "dumpbin" output, the "FPC_INITIALIZEUNITS" and "fpc_initializeunits" point to the same address in object memory.

Maybe this problem occurs because FPC uses a custom linking script and the "FPC_INITIALIZEUNITS" searches for specific addresses in memory depends on the linking script.

As written above: one is merely an alias of the other. They're indeed expected to be the same.

[tihory]

Hi,
I implemented some other features but postponed development for now.

Features:

• Link multiple object files together
• Link against DLL files
• Support Pascal Mangling for external DLL functions
• Support function injection