[fpc-devel] First cppclass test

[Sven Barth]

Hello together!

After I sent the first Native NT patches to the bugtracker I found some 
time to test the cppclass-feature.

The following class compiles with 2.5.1:

   TestClass = cppclass
     procedure Test1; external 'cpplib.so';
     function Test2: LongInt; external 'cpplib.so';
   end;

The 'external' after each method is required as you can't add a 
'external' after the class definition (I think I'll have to look at 
Jonas' objc branch to see how he solved that...).


Adding a method with a parameter results in an internal error 2103001. 
This is in symdef.tprocdef.cplusplusmangledname in the local method 
getcppparaname. The reason is the hidden self parameter which isn't 
checked for in cplusplusmangledname. I've attached a patch were I added 
a check for hidden parameters in the parameter-for-loop. If you think 
that patch is ok I'll post it to the bugtracker.


The following program compiles and runs (the result of Test2 is printed 
- in my case 42 ^^), but there is a runtime error 217 after FreeClass 
(with "after" I mean that a Writeln after FreeClass is executed)

program cpptest1;

{$mode objfpc}{$H+}

type
   TestClass = cppclass
     procedure Test1; external 'cpplib.so';
     function Test2: LongInt; external 'cpplib.so';
     procedure Test3(aArg1: LongInt); external 'cpplib.so';
   end;
   PTestClass = ^TestClass;

function NewClass: PTestClass; cdecl; external 'cpplib.so';
procedure FreeClass(aUser: PTestClass); cdecl; external 'cpplib.so';

var
   c: PTestClass;
   i: LongInt;
begin
   c := NewClass; // internal error
   try
     i := c^.Test2;
     Writeln(i);
   finally
     FreeClass(c);
   end;
end.

The Pointer type is required, because a cppclass does not seem to be 
handled as a implicit pointer. When I don't use a pointer type I get an 
internal error 200301231 (x86/cpubase.cgsize2subreg) on the line "c := 
NewClass".
As I'd like to have a cppclass behave like a normal class, I'd like to 
know where I can setup a cppclass reference as an implicit reference 
inside the compiler.


All in all I have the following goals for (my) future work on this:
* make a cppclass an implicit pointer
* use only one "external 'foo'" after the class declaration


Regards,
Sven

PS: when answering, please CC me, because I'm using digest mode :)
-------------- next part --------------
--- fpc/compiler/symdef.pas	2009-10-22 20:30:05.000000000 +0200
+++ fpc-build/compiler/symdef.pas	2009-10-28 21:08:16.000000000 +0100
@@ -3488,6 +3488,9 @@
              for i:=0 to paras.count-1 do
                begin
                  hp:=tparavarsym(paras[i]);
+                 { we ignore all hidden parameters (like self) }
+                 if vo_is_hidden_para in hp.varoptions then
+                   continue;
                  s2:=getcppparaname(hp.vardef);
                  if hp.varspez in [vs_var,vs_out] then
                    s2:='R'+s2;