On Fri, 13 Feb 2026 18:58:47 GMT, Frederic Parain <[email protected]> wrote:
>> First batch of changes to remove potentially dangerous calls to
>> objArrayOopDesc::obj_at().
>> Changes are more extensive than intended. In most cases, code modifications
>> consist in using a refArrayOop type instead of a objArrayOop type, because
>> most of the arrays the JVM deals with for its own purpose are always
>> reference arrays (because they are arrays of identity type elements). The
>> patch also adds a new API allowing the VM to request the allocation of a
>> reference array.
>> Code dealing with user provided arrays must be ready to handle exceptions
>> when accessing objArrays.
>>
>> This is a short term fix, fixing a few bugs, and trying to make the code
>> more robust using the meta-data types. For the long term, a better solution
>> is needed. Accesses to both arrays and fields are becoming more and more
>> complex because of the introduction of flattening, multiple layouts,
>> additional properties. Forcing enforcement at each access would be expensive
>> and wasteful, as the JVM usually operates on well-known objects or arrays.
>> But because of the increasing complexity, having a way to quickly check the
>> validity of an access would help making the VM code more robust.
>
> Frederic Parain has updated the pull request incrementally with two
> additional commits since the last revision:
>
> - Fixes from Stefan's comments
> - Fix more use sites and some TRAPS returns
Copyright year unchanged in some of the files.
src/hotspot/share/ci/ciArray.cpp line 66:
> 64: {
> 65: if (ary->is_refArray()) {
> 66: refArrayOop refary = refArrayOopDesc::cast(ary);
oop_cast<refArrayOop>(ary);
src/hotspot/share/oops/oopCast.inline.hpp line 43:
> 41: template<>
> 42: inline bool is_oop_type<refArrayOop>(oop theOop) { return
> theOop->is_refArray(); }
> 43: template<>
add:
template<>
inline bool is_oop_type<flatArrayOop>(oop theOop) { return
theOop->is_flatArray(); }
So we can get rid of `flatArrayOopDesc::cast`
src/hotspot/share/prims/foreignGlobals.inline.hpp line 36:
> 34: template<typename T>
> 35: void ForeignGlobals::parse_register_array(objArrayOop jarray, StorageType
> type_index, GrowableArray<T>& array, T (*converter)(int)) {
> 36: refArrayOop refarray = refArrayOopDesc::cast(jarray);
why not use `oop_cast` as below? And probably remove `flatArrayOopDesc::cast`
so we don't introduce new uses of `flatArrayOopDesc::cast`. Eventually get rid
of `refArrayOopDesc::cast` (it is already used in so many places).
-------------
PR Review:
https://git.openjdk.org/valhalla/pull/2033#pullrequestreview-3808558955
PR Review Comment:
https://git.openjdk.org/valhalla/pull/2033#discussion_r2812405012
PR Review Comment:
https://git.openjdk.org/valhalla/pull/2033#discussion_r2812411792
PR Review Comment:
https://git.openjdk.org/valhalla/pull/2033#discussion_r2812364079
