On Wed, 5 Aug 2020 at 23:14, Eduardo Habkost <ehabk...@redhat.com> wrote: > On Wed, Aug 05, 2020 at 09:41:25PM +0100, Peter Maydell wrote: > > This is one of those areas where this change works and reduces > > amount of code, but on the other hand it means the QOM type > > doesn't follow the common pattern for a leaf type of: > > * it has a struct > > * it has cast macros that cast to that struct > > * the typeinfo instance_size is the size of that struct > > (it wasn't exactly following this pattern before, of course). > > Is this really a pattern that exists and we want to follow? > I don't see why that pattern would be useful for simple leaf > types.
Most leaf types need this. Consider a simple device type like TYPE_CMSDK_APB_UART. It has a TYPE_* name so that users of it can instantiate it; it has a CMSDKAPBUART struct that holds all the device state; it has the CMSDK_APB_UART() cast macro so that code that gets a Device* or Object* can get at the struct. Leaf types like ide-hd which have no actual state of their own are I think the less common case: most leaf types do have at least some member variables. As Markus says, we can have a couple of standard patterns if we want to (as we do for the class-macro conventions); I just wanted to explain that lots of leaf types work the way I outline above. thanks -- PMM
