RFR: 8332461: ubsan : dependencies.cpp:906:3: runtime error: load of value 4294967295, which is not a valid value for type 'DepType' [v2]

[Dean Long]

On Wed, 4 Sep 2024 09:49:49 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

>> The error mentioned in the JBS issue is seen on x86_64 as well as on s390x during the build, with `--enable-ubsan` configuration. 
>> 
>> I have added `-1` to enum to fix this issue for now as mentioned by @MBaesken. But removing the assert itself is also a possible solution, mentioned on the JBS issue. 
>> 
>> So I will happy to follow the reviews/suggestion if this is not a good fix.
>
> Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   initialise with undefined_dependency

Marked as reviewed by dlong (Reviewer).

src/hotspot/share/code/dependencies.hpp line 107:

> 105:   enum DepType {
> 106:     // _type is initially set to -1, to prevent "already at end" assert
> 107:     undefined_dependency = -1,

Preserving the existing value seems fine, though it appears any value >= TYPE_LIMIT would work just as well.

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PR Review: https://git.openjdk.org/jdk/pull/20847#pullrequestreview-2281759910
PR Review Comment: https://git.openjdk.org/jdk/pull/20847#discussion_r1744738207