Strange write barrier code in core_ops.c

[Andy Dougherty]

Is it just me, or is the write barrier in this snippet from core_ops.c
in the wrong place?  Note the "return" on the line above it!

 20508	opcode_t *
 20509	Parrot_subclass_p_p(opcode_t *cur_opcode, PARROT_INTERP)  {
 20510	
 20511	    PMC      * const parent_class = Parrot_oo_get_class(interp, PREG(2));
 20512	    opcode_t * const next         = cur_opcode + 3;
 20513	
 20514	    if (PMC_IS_NULL(parent_class)) {
 20515	        opcode_t * const handler = Parrot_ex_throw_from_op_args(interp, next,
 20516	            EXCEPTION_NO_CLASS,
 20517	            "Class '%Ss' doesn't exist", VTABLE_get_string(interp, PREG(2)));return (opcode_t *)handler;
 20518	    }
 20519	    PREG(1) = Parrot_pmc_new(interp, enum_class_Class);
 20520	    VTABLE_add_parent(interp, PREG(1), parent_class);return (opcode_t *)next;
 20521	    PARROT_GC_WRITE_BARRIER(interp, CURRENT_CONTEXT(interp));
 20522	}

Also, in many of the files generated from PMCs, there are strange 
placements of return and GC_WRITE_BARRIER statements.  Here's an excerpt 
from src/pmc/float.c.  Note the write barrier on line 432, the return on 
433, and another write barrier on line 440.  I'd estimate there are about 
200 more such examples.

   412	static  void
   413	Parrot_Float_nci_acos(PARROT_INTERP, PMC *_self)
   414	{
   415	    PMC * const _ctx         = CURRENT_CONTEXT(interp);
   416	    PMC * const _call_object = Parrot_pcc_get_signature(interp, _ctx);
   417	    PMC * _ret_object;
   418	
   419	    { /* BEGIN PARMS SCOPE */
   420	
   421	        Parrot_pcc_fill_params_from_c_args(interp, _call_object, "Pi",
   422	            &_self);
   423	    { /* BEGIN PMETHOD BODY */
   424	
   425	    PMC * const d  = Parrot_pmc_new(interp, VTABLE_type(interp, _self));
   426	    SETATTR_Float_fv(interp, d, acos(_self->vtable->get_number(interp, _self)));
   427	        {
   428	    /*BEGIN RETURN PMC *d */
   429	    _ret_object = Parrot_pcc_build_call_from_c_args(interp, _call_object,
   430	        "P", (PMC*)d);
   431	    UNUSED(_ret_object);
   432	    PARROT_GC_WRITE_BARRIER(interp, _self);
   433	    return;
   434	    /*END RETURN PMC *d */
   435	    }
   436	
   437	
   438	    } /* END PMETHOD BODY */
   439	
   440	    PARROT_GC_WRITE_BARRIER(interp, _self);
   441	
   442	    } /* END PARAMS SCOPE */
   443	    return;
   444	}

-- 
    Andy Dougherty		doughera at lafayette.edu