C++ BasicObjectLock::lock方法代码示例

GrowableArray<MonitorInfo*>* interpretedVFrame::monitors() const {
  GrowableArray<MonitorInfo*>* result = new GrowableArray<MonitorInfo*>(5);
  for (BasicObjectLock* current = (fr().previous_monitor_in_interpreter_frame(fr().interpreter_frame_monitor_begin()));
       current >= fr().interpreter_frame_monitor_end();
       current = fr().previous_monitor_in_interpreter_frame(current)) {
    result->push(new MonitorInfo(current->obj(), current->lock(), false, false));
  }
  return result;
}

void vframeArrayElement::fill_in(compiledVFrame* vf) {

// Copy the information from the compiled vframe to the
// interpreter frame we will be creating to replace vf

  _method = vf->method();
  _bci    = vf->raw_bci();
  _reexecute = vf->should_reexecute();

  int index;

  // Get the monitors off-stack

  GrowableArray<MonitorInfo*>* list = vf->monitors();
  if (list->is_empty()) {
    _monitors = NULL;
  } else {

    // Allocate monitor chunk
    _monitors = new MonitorChunk(list->length());
    vf->thread()->add_monitor_chunk(_monitors);

    // Migrate the BasicLocks from the stack to the monitor chunk
    for (index = 0; index < list->length(); index++) {
      MonitorInfo* monitor = list->at(index);
      assert(!monitor->owner_is_scalar_replaced(), "object should be reallocated already");
      assert(monitor->owner() == NULL || (!monitor->owner()->is_unlocked() && !monitor->owner()->has_bias_pattern()), "object must be null or locked, and unbiased");
      BasicObjectLock* dest = _monitors->at(index);
      dest->set_obj(monitor->owner());
      monitor->lock()->move_to(monitor->owner(), dest->lock());
    }
  }

  // Convert the vframe locals and expressions to off stack
  // values. Because we will not gc all oops can be converted to
  // intptr_t (i.e. a stack slot) and we are fine. This is
  // good since we are inside a HandleMark and the oops in our
  // collection would go away between packing them here and
  // unpacking them in unpack_on_stack.

  // First the locals go off-stack

  // FIXME this seems silly it creates a StackValueCollection
  // in order to get the size to then copy them and
  // convert the types to intptr_t size slots. Seems like it
  // could do it in place... Still uses less memory than the
  // old way though

  StackValueCollection *locs = vf->locals();
  _locals = new StackValueCollection(locs->size());
  for(index = 0; index < locs->size(); index++) {
    StackValue* value = locs->at(index);
    switch(value->type()) {
      case T_OBJECT:
        assert(!value->obj_is_scalar_replaced(), "object should be reallocated already");
        // preserve object type
        _locals->add( new StackValue((intptr_t) (value->get_obj()()), T_OBJECT ));
        break;
      case T_CONFLICT:
        // A dead local.  Will be initialized to null/zero.
        _locals->add( new StackValue());
        break;
      case T_INT:
        _locals->add( new StackValue(value->get_int()));
        break;
      default:
        ShouldNotReachHere();
    }
  }

  // Now the expressions off-stack
  // Same silliness as above

  StackValueCollection *exprs = vf->expressions();
  _expressions = new StackValueCollection(exprs->size());
  for(index = 0; index < exprs->size(); index++) {
    StackValue* value = exprs->at(index);
    switch(value->type()) {
      case T_OBJECT:
        assert(!value->obj_is_scalar_replaced(), "object should be reallocated already");
        // preserve object type
        _expressions->add( new StackValue((intptr_t) (value->get_obj()()), T_OBJECT ));
        break;
      case T_CONFLICT:
        // A dead stack element.  Will be initialized to null/zero.
        // This can occur when the compiler emits a state in which stack
        // elements are known to be dead (because of an imminent exception).
        _expressions->add( new StackValue());
        break;
      case T_INT:
        _expressions->add( new StackValue(value->get_int()));
        break;
      default:
        ShouldNotReachHere();
    }
  }
}

//.........这里部分代码省略.........
#else
     // TBD: Need to implement ForceEarlyReturn for CC_INTERP (ia64)
#endif
    } else {
      // Possibly override the previous pc computation of the top (youngest) frame
      switch (exec_mode) {
      case Deoptimization::Unpack_deopt:
        // use what we've got
        break;
      case Deoptimization::Unpack_exception:
        // exception is pending
        pc = SharedRuntime::raw_exception_handler_for_return_address(thread, pc);
        // [phh] We're going to end up in some handler or other, so it doesn't
        // matter what mdp we point to.  See exception_handler_for_exception()
        // in interpreterRuntime.cpp.
        break;
      case Deoptimization::Unpack_uncommon_trap:
      case Deoptimization::Unpack_reexecute:
        // redo last byte code
        pc  = Interpreter::deopt_entry(vtos, 0);
        use_next_mdp = false;
        break;
      default:
        ShouldNotReachHere();
      }
    }
  }

  // Setup the interpreter frame

  assert(method() != NULL, "method must exist");
  int temps = expressions()->size();

  int locks = monitors() == NULL ? 0 : monitors()->number_of_monitors();

  Interpreter::layout_activation(method(),
                                 temps + callee_parameters,
                                 popframe_preserved_args_size_in_words,
                                 locks,
                                 caller_actual_parameters,
                                 callee_parameters,
                                 callee_locals,
                                 caller,
                                 iframe(),
                                 is_top_frame,
                                 is_bottom_frame);

  // Update the pc in the frame object and overwrite the temporary pc
  // we placed in the skeletal frame now that we finally know the
  // exact interpreter address we should use.

  _frame.patch_pc(thread, pc);

  assert (!method()->is_synchronized() || locks > 0, "synchronized methods must have monitors");

  BasicObjectLock* top = iframe()->interpreter_frame_monitor_begin();
  for (int index = 0; index < locks; index++) {
    top = iframe()->previous_monitor_in_interpreter_frame(top);
    BasicObjectLock* src = _monitors->at(index);
    top->set_obj(src->obj());
    src->lock()->move_to(src->obj(), top->lock());
  }
  if (ProfileInterpreter) {
    iframe()->interpreter_frame_set_mdx(0); // clear out the mdp.
  }
  iframe()->interpreter_frame_set_bcx((intptr_t)bcp); // cannot use bcp because frame is not initialized yet