On Mon, 4 Nov 2024 03:08:02 GMT, Ioi Lam <ik...@openjdk.org> wrote: >> src/hotspot/share/cds/aotClassInitializer.cpp line 348: >> >>> 346: } >>> 347: JavaValue result(T_VOID); >>> 348: JavaCalls::call_static(&result, ik, >> >> Based on the discussions in JDK-8342283, do we need a memory fence after the >> call to runtimeSetup? >> >> I think we do to be consistent with the non-AOTCache run as there is a fence >> after `<clinit>` (when this code would normally run) due to the >> initialization lock. > > I think this is already done: > > `runtimeSetup()` is called inside `InstanceKlass::call_class_initializer()`. > When that returns, we will proceed to > `InstanceKlass::set_initialization_state_and_notify()` which will perform the > memory fencing. > > https://github.com/iklam/jdk/blob/6eebd18fc2820ffb179d431f179fc6af6d1be247/src/hotspot/share/oops/instanceKlass.cpp#L1276-L1300
I think you're right about the memory fencing being covered there but reading that code shows another potential issue - what if the `runtimeSetup()` call throws an exception? If I read `InstanceKlass::call_class_initializer()` correctly, an exception from `runtimeSetup()` will lead to marking the class as failing initialization (`initialization_error`) which will be an unexpected outcome as there may be instances of the class in the AOTCache that aren't produced by paths through the `<clinit>` method. Classes are able to create an instance in `<clinit>` and escape it to other code and then fail initialization. The instances are left in an odd state where after the `<clinit>` the instance methods can be called but static fields and static methods can't be accessed. `runtimeSetup()` expands on this corner case which I think is OK for current "crawl" stage of our "crawl-walk-run" approach as its analogous to the existing `<clinit>` behaviour. It may need refining in the future to abort the VM or do something else (?) in the case of failed `runtimeSetup` calls ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/21642#discussion_r1827813351
