RFR: 8364103: Convert existing sprintf-chains to stringStream [v2]
Paul Hübner
phubner at openjdk.org
Thu Sep 4 13:12:35 UTC 2025
> Hi all,
>
> This PR refactors `javaClasses`' `print_stack_element_to_stream` to use a `stringStream` instead of manually maintaining a buffer with `os::snprintf` chains.
>
> The JBS issue outlines to do this for all occurrences of `snprintf`-like chains. The majority of the calls to `os::snprintf`, `os::snprintf_checked`, `os::vsnprintf`, etc. occur just once. `LogTagSet::vwrite` is the only place to my knowledge where there remains a `vsnprintf` chain using manual buffer arithmetic. After consulting @jdksjolen, we decided that due to the
> a) low-level nature of the code, and
> b) widespread usage of logging in the VM,
> this should probably warrant a larger discussion and/or separate issue. Personally, I feel like the performance & correctness risks of introducing a high-level abstraction here outweighs the benefits.
>
> I've run tests with JDK tiers 1-3 on macOS (AArch64, x64), Linux (AArch64, x64), and Windows (x64); all green.
Paul Hübner has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:
- Incorporate reviewer feedback.
- Merge branch 'master' into JDK-8364103
- Refactor stack trace printing to use stringStream.
-------------
Changes: https://git.openjdk.org/jdk/pull/26894/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26894&range=01
Stats: 32 lines in 1 file changed: 5 ins; 15 del; 12 mod
Patch: https://git.openjdk.org/jdk/pull/26894.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/26894/head:pull/26894
PR: https://git.openjdk.org/jdk/pull/26894
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