[fpc-devel] FPC internal linker issues with Win64 .a startic-link libraries by GCC newer than 4.8.1

[Benjamin Rosseaux]

oh, "then FPC links it with any error." should be "then FPC links it
without any error."

On Sun, Sep 18, 2016 at 2:31 AM, Benjamin Rosseaux <benjamin at rosseaux.de>
wrote:

> Hello,
>
> i've noticed a weakness of the FPC internal linker at static-linking .a
> libraries on the Win64 target, which're generated by GCC newer than 4.8.1,
> due to the new refptr.* and .refptr.* symbols-can-be-multiple-defined
> stuff (inside one single .a library file), which was introduced in newer
> GCC versions.
>
> For example, when I do to want link SDL2 statically to my FPC code, where
> the libSDL2.a as Win64 StaticLink Build was generated with GCC 4.9.1 or
> newer, then FPC abort with a error and outputs:
>
> > Free Pascal Compiler version 3.1.1 [2016/08/22] for x86_64
> > Copyright (c) 1993-2016 by Florian Klaempfl and others
> > Target OS: Win64 for x64
> > Compiling racegame.dpr
> > Linking racegame_x86_64.exe
> > Error: Multiple defined symbol .refptr.SDL_free_REAL
> > Error: Multiple defined symbol .refptr.SDL_XInputGetCapabilities
> > Error: Multiple defined symbol .refptr.SDL_Appname
> > Error: Multiple defined symbol .refptr.SDL_Instance
> > Error: Multiple defined symbol .refptr.SYS_Joystick
> > Error: Multiple defined symbol .refptr.SDL_XInputSetState
> > Error: Multiple defined symbol .refptr.SDL_HelperWindow
> > Error: Multiple defined symbol .refptr.GUID_XAxis
> > Error: Multiple defined symbol .refptr.GUID_YAxis
> > Error: Multiple defined symbol .refptr.GUID_ZAxis
> > Error: Multiple defined symbol .refptr.GUID_RxAxis
> > Error: Multiple defined symbol .refptr.GUID_RyAxis
> > Error: Multiple defined symbol .refptr.GUID_RzAxis
> > Error: Multiple defined symbol .refptr.IID_IDirectInput8W
> > Error: Multiple defined symbol .refptr.CLSID_DirectInput8
> > Error: Multiple defined symbol .refptr.SDL_hapticlist
> > Error: Multiple defined symbol .refptr.IID_IDirectInputDevice8W
> > Error: Multiple defined symbol .refptr.SDL_expand_byte
> > Error: Multiple defined symbol .refptr.SDL_expand_byte
> > Error: Multiple defined symbol .refptr.SDL_expand_byte
> > Error: Multiple defined symbol .refptr.SDL_expand_byte
> > Error: Multiple defined symbol .refptr.SDL_expand_byte
> > Error: Multiple defined symbol .refptr.SDL_expand_byte
> > Error: Multiple defined symbol .refptr.SDL_expand_byte
> > Error: Multiple defined symbol .refptr.SDL_expand_byte
> > Fatal: There were 25 errors compiling module, stopping
> > Fatal: Compilation aborted
>
> But for example, when I do to want the same, but where the libSDL2.a as
> Win64 StaticLink Build was generated this time with GCC 4.8.1 or older,
> then FPC links it with any error.
>
> So I did some research on this issue and found https://gcc.gnu.org/ml/gcc-
> patches/2013-03/msg00858.html in the gcc-patches mailing list and tp://
> stackoverflow.com/questions/28012075/what-does-
> refptr-mean-in-a-mingw64-def-file , so I've looked at ogbase.pas of
> FreePascal, and try to write a beginning patch, which I've attached it to
> this mail. So someone, who are more inside the FreePascal source code
> structure, should finish this patch.
>
> Regards,
> Benjamin 'BeRo' Rosseaux
>
>
>
>
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