RFR: 8017234: Hotspot should stop using mapfiles

[Magnus Ihse Bursie]

On Thu, 22 Feb 2024 14:28:48 GMT, Erik Joelsson <erikj at openjdk.org> wrote:

> Regarding SUNWprivate_1.1, reading [JDK-4916160](https://bugs.openjdk.org/browse/JDK-4916160) it seems like it could cause problems for native user libraries linked against an older JDK version if we remove it. I think this is what David Holmes was referring to. So it seems like a good idea to figure out a way to keep it around.

"Forward compatibility issue : 1.4.1_03 onwards". Wow, that's a blast from the past! The sins of the fathers, etc. :)

I'm not sure I understand JDK-4916160 completely, but it seems they had the opposite situation -- prior to 1.4.1_03 we did not link with version scripts, and from 1.4.1_03 we did. And this was closed as "not an issue".

Nevertheless, I have found a way to keep the `SUNWprivate_1.1` that is not too ugly, so with the latest commit to this PR I am doing that. I have now verified that this makes no visible difference in the symbol tables at all between the current libjvm.so and the one produced with this patch on gcc. There is still a difference in the ordering of symbols; it seems like the linker is using a hash table and something is making it different -- perhaps the explicit ordering given in the old mapfile affected the way the linker produced the output. So it is still not a bit-by-bit equality, but it is as far as it is reasonable to get.

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PR Comment: https://git.openjdk.org/jdk/pull/17955#issuecomment-1959646396