# AC_CHECK_FASTCALL([if-ok],[if-notok])

# Test if the compiler recognizes __attribute__((regparm(3))) - we don't 

# currently check if it actually works correctly, but probably should...

# -----------------------

AC_DEFUN([AC_CHECK_FASTCALL], [

AC_MSG_CHECKING([support for fastcall calling conventions]);

AC_RUN_IFELSE([

  AC_LANG_SOURCE([[

int __attribute__((regparm(3))) foo(int a, int b) { return a+b; }

int main(int argc, char *argv[])

{

   return foo( 1, 2 ) == 3 ? 0 : 1;

}]])], [ 

   AC_MSG_RESULT([yes])

   $1 ], [ 

   AC_MSG_RESULT([no])

   $2 ])

])

# AC_CHECK_FRAME_ADDRESS([if-ok],[if-notok])

# Test if the compiler will let us modify the return address on the stack

# via __builtin_frame_address()

# -----------------------

AC_DEFUN([AC_CHECK_FRAME_ADDRESS], [

AC_MSG_CHECKING([if we have a working __builtin_frame_address()]);

AC_RUN_IFELSE([

  AC_LANG_SOURCE([[

void * __attribute__((noinline)) first_arg( void *x, void *y ) { return x; }

int __attribute__((noinline)) foo( int arg, void *exc )

{

    if( arg < 2 ) {

        *(((void **)__builtin_frame_address(0))+1) = exc;

    }

    return 0;

}

int main(int argc, char *argv[])

{

   goto *first_arg(&&start, &&except);

start:

   return foo( argc, &&except ) + 1;

except:

   return 0;

}]])], [ 

   AC_MSG_RESULT([yes])

   $1 ], [ 

   AC_MSG_RESULT([no])

   $2 ])

])