On Wed, 23 Aug 2023 18:09:24 GMT, Chris Plummer <cjplum...@openjdk.org> wrote:
>> The intent was to generalize it but the comments also need changing, and now >> I'm not clear what this is actually doing. > > This change wasn't in the original patch, but the > `GENERATE_STATIC_PTR_VOLATILE_VM_STRUCT_ENTRY` change above it was. I found > it when I noticed the use of `GENERATE_STATIC_PTR_VOLATILE_VM_STRUCT_ENTRY` > and thought it should be renamed too. I was also doing "static volatile" -> > "volatile stack" at the time so that is also part of this macros rename. > > As David points out, the purpose is to make it more general purpose, although > for this macro only the name change is needed > (`GENERATE_STATIC_PTR_VOLATILE_VM_STRUCT_ENTRY also has a minor > implementation change that was needed). > > The comments for both of these macros references "static pointer volatile" > entries. That should changed to "volatile static". The type no longer needs > to be a pointer type. > > I'm not certain what this CHECK macro does, but it was pre-existing, and > there is also the `CHECK_STATIC_VM_STRUCT_ENTRY` macro above it which is > identical except of the absence of "volatile" in the name and implementation. > I think it verifies that the type specified in the vmstructs definition of > the field is actually the same as the field itself. The macro will generate > a compiler error if a cast was needed. I think this type of check can only be > done with static fields. You would need an instance of the class/struct to do > a similar check on an instance field. Thus CHECK_NONSTATIC_VM_STRUCT_ENTRY is > much more complex and seems to be a runtime check that will assert if it > fails. I can't convince myself that `volatile` is in the right place in `type volatile * dummy`. But `volatile * dummy` means that the pointer is volatile as opposed to the type being pointed to, which would match with the original macro name's use of `PTR_VOLATILE`. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/15373#discussion_r1303612740
