RFR: 8331731: ubsan: relocInfo.cpp:155:30: runtime error: applying non-zero offset 18446744073709551614 to null pointer [v3]

[Vladimir Kozlov]

On Fri, 31 May 2024 11:37:55 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> I guess Matthias only wanted to fix UB in hotspot ASAP and doesn't have the bandwidth to change the design everywhere. Sounds like you guys already have an alternative solution which already works. Maybe you would like to put it into a PR and we continue the discussion there?
>> Nevertheless, having `sub / add_to_ptr_maybe_null` available in hotspot may be a good thing. There are some places where we really use additions with nullptr (e.g. `index_oop_from_field_offset_long` in unsafe.cpp).
>
>> I guess Matthias only wanted to fix UB in hotspot ASAP and doesn't have the bandwidth to change the design everywhere. 
> 
> Yes .
> The first goal to make the '--enable-ubsan' configure flag useful;  currently we have the configure flag but still fail already in the OpenJDK build (because of a number of ubsan related issues in HS).

@MBaesken can  close this PR and re-assign this bug to me if he don't have time to do proposed changes to code.

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PR Comment: https://git.openjdk.org/jdk/pull/19424#issuecomment-2142756992