RPython and Stack

interp.c

// stack_ptr = -1
//     stack = [None] * max_stack_size
//     make_sure_not_resized(stack)
// ...
// while True:
// ...
//     elif bytecode == Bytecodes.push_frame_0:
//        stack_ptr += 1
//        stack[stack_ptr] = read_frame(frame, FRAME_AND_INNER_RCVR_IDX + 0)


case 3L:
    OP_INT_ADD(l_stack_ptr_8, 1L, l_stack_ptr_11);
    RPyAssert(1, "unexpectedly negative list getitem index");
    l_v45265 = l_frame_8->length; 
    OP_INT_LT(1L, l_v45265, l_v45266);
    RPyAssert(l_v45266, "fixed getitem out of bounds");
    l_v45268 = RPyItem(l_frame_8, 1L);
    l_v45269 = (struct pypy_som_vmobjects_abstract_object_AbstractObject0 *)l_v45268;
    l_newitem_9 = (struct pypy_object0 *)l_v45269;
    
    // STEFAN: relevant bits here
    OP_INT_LT(l_stack_ptr_11, 0L, l_v45270);  // STEFAN: stack_ptr out of bounds is never used, so, not needed
    if (l_v45270) {  // STEFAN: Ideally, this block wouldn't exist
        /* block49: (inlined) */
        l_v45279 = l_stack_7->length;
        OP_INT_ADD(l_stack_ptr_11, l_v45279, l_index_461);
        OP_INT_GE(l_index_461, 0L, l_v45280);
        RPyAssert(l_v45280, "negative list setitem index out of bound");
        l_index_402 = l_index_461;
        goto block46;
    }
    l_index_402 = l_stack_ptr_11;
    goto block46;
    block46:
    l_v45271 = l_stack_7->length;                  // STEFAN: ideally, not needed
    OP_INT_LT(l_index_402, l_v45271, l_v45272);    // STEFAN: ideally, not needed
    RPyAssert(l_v45272, "fixed setitem out of bounds");    // STEFAN: ideally, not needed
    l_addr_array_108 = (void*)l_stack_7;
    OP_ADR_SUB(l_addr_array_108, 0, l_addr_700);
    l_v45274 = (struct pypy_header0 *)l_addr_700;
    l_v45275 = ((char *)l_v45274)[4] & 1;
    OP_INT_IS_TRUE(l_v45275, l_v45276);
    if (l_v45276) {
        /* block48: (inlined) */
        pypy_g_remember_young_pointer_from_array2(l_addr_array_108, l_index_402);
        goto block47;
    }
    goto block47;
    block47:
    RPyItem(l_stack_7, l_index_402) = l_newitem_9;  // STEFAN: Ideally, that's all that's done
    l_stack_ptr_50 = l_stack_ptr_11;