RFR: 8363837: Move StubRoutines::_crc_table_adr initialization to preuniverse stubs [v2]
Vladimir Kozlov
kvn at openjdk.org
Wed Jul 23 02:00:43 UTC 2025
> `StubRoutines::_crc_table_adr` and `_crc32c_table_addr` are used by initial stubs. In Leyden these addresses should be recorded in `AOTCodeAddressTable` to be used by AOTed stubs. But recording in `AOTCodeAddressTable` is done in `AOTCodeCache::init2()` which is called before initial stubs are generated and `_crc*_table_addr` are set.
>
> We need to move `_crc_table_addr` and `_crc32c_table_addr` initialization to `preuniverse` blob to be available in `AOTCodeCache::init2()`.
>
> I also renamed `_crc_table_adr` to `_crc_table_addr` to match other names.
>
> During testing I found that `-Xlog:stubs` affects empty blobs generation. There was typo there: `return nullptr;` was in wrong place.
>
> I have to specify sizes of `preuniverse` blobs so they are called after I fixed typo. `32` bytes is cache line size on most CPUs. Note, there will be no assembler code generation for this case: `_crc*_table_addr` are initialized by address of C tables.
>
> I did not move `_crc*_table_addr` declaration in `stubDeclarations.hpp` from `init` to `preuniverse` blob. I tried but there is issue: they require to specify stub name and I can move `updateBytesCRC32` stub declaration. I tries add fake stub but it did not work. I would prefer if I could use `nullptr` instead of stub in such case. But it will complicate other code. I think it is fine `do_entry()` macro only creates field and accessor function.
>
> Tested: tier1-4,tier10-rt,xcomp,stress
Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:
Fixed Zero VM
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/26434/files
- new: https://git.openjdk.org/jdk/pull/26434/files/08f27284..6459712d
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=26434&range=01
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=26434&range=00-01
Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
Patch: https://git.openjdk.org/jdk/pull/26434.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/26434/head:pull/26434
PR: https://git.openjdk.org/jdk/pull/26434
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