ev@chorus.fr (Eric Valette) (01/14/91)
/*
* The following small c++ program has been translated to c using
* one Cfront 2.0 port. If you look at generated c code, you will
* see that the code generated for inlines member functions is different
* for local variables and global variables (it is also true for global
* pointer)
*
* Could someone explain me why ?
*
* PS: I think that the code is ineffective. Tell me if I am wrong.
*
*/
/*
*
* Sorry to post it in these news group, I have already post it in
* comp.lang.c++ and got no answer.
*/
/* Small C++ program
* --------------------------------------------------------------------------
*
*/
class example {
private :
int a;
public :
int getVal() {return a;}
void setVal(int val) {a = val;}
};
example glob;
void f()
{
example loc;
int a = 1;
int b = 2;
int resu;
loc.setVal(1);
resu = loc.getVal();
glob.setVal(1);
resu = glob.getVal();
}
/*
* Generated C code
* -------------------------------------------------------------------------
*
*/
/* <<AT&T C++ Translator 2.00.02 08/25/89>> */
/* < kt34.cxx > */
char *__vec_new ();
char __vec_delete ();
typedef int (*__vptp)();
struct __mptr {
short d;
short i;
__vptp f;
};
struct example { /* sizeof example == 4 */
int a__7example ;
};
struct example glob = {
0 };
char f__Fv ()
{
struct example __1loc ;
int __1a ;
int __1b ;
int __1resu ;
struct example *__0__Xthis00a3jpkk ;
struct example *__0__Xthis0020bpkk ;
__1a = 1 ;
__1b = 2 ;
( ((&__1loc )->a__7example = 1 ), (((char )0 ))) ;
__1resu = ( (&__1loc )->a__7example ) ;
/*
* for local variables the c code is what I expected.
*/
( (__0__Xthis00a3jpkk = (&glob )), ( (__0__Xthis00a3jpkk ->a__7example = 1 ), (((char )0 ))) ) ;
__1resu = ( (__0__Xthis0020bpkk = (&glob )), ( __0__Xthis0020bpkk ->a__7example ) ) ;
/*
* Why two copies? Why into two differents local variables?
*/
}
--
__
/ ` Eric Valette
/-- __ o _. Chorus Systemes
(___, / (_(_(__ 6 avenue Gustave Eiffel
F-78182, St-Quentin-en-Yvelines-Cedex
Tel: +33 (1) 30 64 82 00 Fax: +33 (1) 30 57 00 66
E-mail: ev@chorus.fr or ev%chorus.fr@mcsun.EU.net