RFR: 8155259: Suspicious buffer allocation in com.sun.tools.javac.file.BaseFileManager [v2]
Archie L. Cobbs
duke at openjdk.org
Thu Nov 17 19:11:14 UTC 2022
> JDK-8155259 notes that in `BaseFileManager` this code:
>
> ByteBuffer.allocate(capacity + capacity>>1)
>
> is actually equivalent (assuming no overflow) to:
>
> ByteBuffer.allocate(capacity)
>
> because in Java the `+` operator has higher precedence than the `>>` operator.
>
> In the bug it is suggested that this be changed to reflect the presumed original intent to over-allocate by 50%, i.e.:
>
> ByteBuffer.allocate(capacity + (capacity>>1))
>
> however, this patch is more conservative in that it leaves the existing behavior alone and instead just simplifies it to:
>
> ByteBuffer.allocate(capacity)
>
> allowing us to at least resolve JDK-8155259.
Archie L. Cobbs has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:
- Merge branch 'master' into JDK-8155259
- 8155259: Suspicious buffer allocation in com.sun.tools.javac.file.BaseFileManager
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/10803/files
- new: https://git.openjdk.org/jdk/pull/10803/files/b3f88603..4dfeba3b
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=10803&range=01
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=10803&range=00-01
Stats: 232655 lines in 2313 files changed: 113387 ins; 82545 del; 36723 mod
Patch: https://git.openjdk.org/jdk/pull/10803.diff
Fetch: git fetch https://git.openjdk.org/jdk pull/10803/head:pull/10803
PR: https://git.openjdk.org/jdk/pull/10803
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