[Mono-list] Method signature modification

[Shankari]

I am trying to invoke unmanaged call with a  flag as
the first parameter of the call. (Since C doesnt do
parameter matching, I can get away with this).
So, i call f( flag, param1)

The corresponding call that is invoked in the shared
library is f(param1).

So, the first parameter is like a flag to mono, I dont
want to push it on stack/marshal it. 


mono_marshal_get_native_wrapper()
 calls mono_marshal_emit_native_wrapper() which sets
up the stack and handles the marshalling.

The method signature "sig" that gets passed to
mono_marshal_emit_native_wrapper( marshal.c) should be
changed to emit the correct wrapper.

Modifying mono code at emit_wrapper seems dangerous.

Any ideas/directions on how to achive this?

Thanks,


--- Jonathan Pryor <jonpryor at vt.edu> wrote:

> On Fri, 2005-10-14 at 20:50 -0700, Shankari wrote:
> > I have some questions in unmanaged call internals.
> > From what I understood, an unmanaged code is a
> > function call.
> 
> <pedantic>
> Unmanaged code can be anything (including Perl
> code), and can be an
> unmanaged *function*.  A function call would invoke
> the function.
> </pedantic>
> 
> > To figure out where exactly the switch from
> managed to
> > unmanaged code is happening, I set a breakpoint in
> my
> > C program and tried a backtrace from it. Here is
> the
> > info I got.
> > 
> > (gdb) backtrace
> > #0  printmsg () at cprog.c:13
> > #1  0x0045b6ac in ?? ()
> > #2  0x00000001 in ?? ()
> > #3  0x00e65710 in ?? ()
> > #4  0x00450ad7 in ?? ()
> > #5  0x093458e0 in ?? ()
> > #6  0x093458c8 in ?? ()
> > #7  0x09389398 in ?? ()
> > #8  0x0002be60 in ?? ()
> > #9  0x00000000 in ?? ()
> > (gdb) n
> > 0x0045b6ac in ?? ()
> > (gdb) 
> 
> Translation of all that: Mono created a new thread
> which contains JITed
> code, so no debug symbols exist (that GDB knows
> about).
> 
> Consequently, you need the managed callstack, which
> you can get using
> mono_print_method_from_ip, which takes a stack
> pointer as an argument,
> e.g.:
> 
> 	(gdb) p mono_print_method_from_ip (0x0045b6ac)
> 
> > I am not able to single step through the code from
> the
> > point where unmanaged code is ending.
> 
> That's because no source code exists for those
> functions, at least as
> far as GDB is concerned.
> 
> > Since the backtrace addr are not resolved, it
> looks
> > like an unmanaged call is spawned in a new thread.
> 
> Correct.  Mono creates several threads during
> startup for myriad reasons
> (such as for the garbage collector, finalizer
> thread, etc.).
> 
>  - Jon
> 
> 
> 



		
__________________________________ 
Yahoo! Music Unlimited 
Access over 1 million songs. Try it free.
http://music.yahoo.com/unlimited/