On Tue, 16 Sep 2025 06:24:25 GMT, David Holmes <[email protected]> wrote:
>> Hi, >> >> This is a refactoring of the way that we store the Bootstrap method >> attribute in the ConstantPool class. We used to have a single `Array<u2>` >> which was divided into a section of `u4` offsets and a section which was the >> actual data. In this refactoring we make this split more clear, by actually >> allocating an `Array<u4>` to store the offsets in and an `Array<u2>` to >> store the data in. These arrays are then put into a `BSMAttributeEntries` >> class, which allows us to separate out the API from that of the rest of the >> `ConstantPool`. >> >> We had multiple instances of the code knowing the layout of the operands >> array and using this to do 'clever' ways of copying and inserting data into >> it. See `ConstantPool::copy_operands` and `ConstantPool::resize_operands`. I >> felt like we could do things in a simpler way, so I added the >> `start_/end_extension` protocol and added the `InsertionIterator` for this. >> See `ClassFileParser::parse_classfile_bootstrap_methods_attribute` for how >> this works. I put several relevant definitions into the inline file in hopes >> of encouraging the compiler to optimize these appropriately. >> >> For the Java SA code, I had to add a `U4Array` class. I also had to fix the >> vmstructs definitions, etc. >> >> On the whole, while this code is a bit less terse, I think it's a good API >> improvement and the underlying implementation of splitting up the operands >> array is also an improvement. >> >> Testing: Oracle Tier1-Tier5 has been run succesfully multiple times. Before >> integration, I will merge with master and run these tiers again. > > src/hotspot/share/prims/jvmtiRedefineClasses.cpp line 49: > >> 47: #include "oops/annotations.hpp" >> 48: #include "oops/constantPool.hpp" >> 49: #include "oops/constantPool.inline.hpp" > > Suggestion: > > #include "oops/constantPool.inline.hpp" > > You don't include the regular header when you include the inline one. I wasn't aware! Thanks > src/hotspot/share/prims/jvmtiRedefineClasses.hpp line 371: > >> 369: intArray * _bsm_index_map_p; >> 370: >> 371: // After merge_constant_pools pass 0 the BSMAttribute entries of >> merge_cp_p will have been expanded to fit scratch_cp. > > This comment doesn't read correctly. There's a missing comma but otherwise it reads fine to me? I added a few more words. There are multiple passes in the method `merge_constant_pools` and they are numbered. // After merge_constant_pools pass 0, the BSMAttribute entries of merge_cp_p will have been expanded to fit // scratch_cp's BSMAttribute entries as well. // However, the newly acquired space will not have been filled in yet. // To append to this new space, the iterator is used. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/27198#discussion_r2351203555 PR Review Comment: https://git.openjdk.org/jdk/pull/27198#discussion_r2351202052
