[cfe-dev] Microsoft constructors implementation problem.

[r4start]

Hi all.

I am working on constructors implementation for MS ABI. Itanium ABI has 
2 constructor types - base & complete. MS ABI has only 1 type.
How it works I'll show on example.
class first {
public:
   virtual void g(){}
};

class second : public virtual first {
public :
   virtual void g(){}
};
When construct instance of second we will have next code
push        1
lea         ecx,[f]
call        second::second ; ctor call

And in ctor
................................................................................
012B19E0  mov         dword ptr [ebp-8],ecx
012B19E3  cmp         dword ptr [ebp+8],0
012B19E7  je          second::second+3Dh (12B19FDh)
012B19E9  mov         eax,dword ptr [this]
012B19EC  mov         dword ptr [eax],offset second::`vbtable' (12B7744h)
012B19F2  mov         ecx,dword ptr [this]
012B19F5  add         ecx,4
012B19F8  call        first::asdf (12B10FAh)
012B19FD  mov         eax,dword ptr [this]
012B1A00  mov         ecx,dword ptr [eax]
012B1A02  mov         edx,dword ptr [ecx+4]
012B1A05  mov         eax,dword ptr [this]
012B1A08  mov         dword ptr [eax+edx],offset second::`vftable' 
(12B77F4h)
012B1A0F  mov         eax,dword ptr [this]
................................................................................
As you can see 'push 1' for MS ABI is like ctor_base & ctor_complete for 
Itanium ABI.
If second ctor was called from another ctor(for example child that 
inherits second) on stack will be pushed 0,
and ctor in second will not initialize vbtable and call first::ctor.

Add new class.

class third : public second, public first {};

................................................................................
002519FE  push        0
00251A00  mov         ecx,dword ptr [this]
00251A03  add         ecx,4  ; this adjustment
00251A06  call        second::second (2510F0h)
................................................................................
This is part of code from third ctor. Before second::ctor call 0 was 
pushed on the stack,
this value tell to second::ctor that vbtable initialization and 
first::ctor call not need.

So my question is: How can I tell llvm that I need push 1 on the stack?

Thx in advance.
  - Dmitry Sokolov.