RFR: 8349752: Tier1 build failure caused by JDK-8349178

[Jiangli Zhou]

On Tue, 11 Feb 2025 06:26:19 GMT, David Holmes <dholmes at openjdk.org> wrote:

> I am at a loss to understand how the initial change built and tested with no problem even though `-ldl` was missing. Maybe there is some way to set a default set of libraries to check and the toolchain include libdl.so in that. ??

@dholmes-ora I just added a comment at https://bugs.openjdk.org/browse/JDK-8349752?focusedId=14751058&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14751058, duplicating below:

I had to refresh my memory on this (I now recall that I've run into related issue in the past), but I know the reason now why the build is successfully even without `-ldl`. `--allow-shlib-undefined` is the default on gnu linker. I linked "binutils/docs-2.18/ld/" below. Is `--no-allow-shlib-undefined` or `--no-undefined` specified for the linker in the closed test environment?

https://sourceware.org/binutils/docs-2.18/ld/Options.html#:~:text=The%20reason%20that%20%2D%2Dallow,be%20resolvable%20at%20load%20time:

> --allow-shlib-undefined
> --no-allow-shlib-undefined
>
> Allows (the default) or disallows undefined symbols in shared libraries. This switch is similar to --no-undefined except that it determines the behaviour when the undefined symbols are in a shared library rather than a regular object file. It does not affect how undefined symbols in regular object files are handled.
> The reason that --allow-shlib-undefined is the default is that the shared library being specified at link time may not be the same as the one that is available at load time, so the symbols might actually be resolvable at load time. Plus there are some systems, (eg BeOS) where undefined symbols in shared libraries is normal. (The kernel patches them at load time to select which function is most appropriate for the current architecture. This is used for example to dynamically select an appropriate memset function). Apparently it is also normal for HPPA shared libraries to have undefined symbols.

Following is the `gcc` & `ld` from the github build machine (https://github.com/jianglizhou/jdk/actions/runs/13124407248/job/36617644281). The linker is `2.38 [GNU ld (GNU Binutils for Ubuntu) 2.38]`.


configure: Using gcc C compiler version 10.5.0 [gcc (Ubuntu 10.5.0-1ubuntu1~22.04) 10.5.0]
...
checking resolved symbolic links for CXX... /usr/bin/x86_64-linux-gnu-g++-10
configure: Using gcc C++ compiler version 10.5.0 [g++ (Ubuntu 10.5.0-1ubuntu1~22.04) 10.5.0]
...
configure: Using gcc linker version 2.38 [GNU ld (GNU Binutils for Ubuntu) 2.38]
configure: comparing linker version to minimum version 2.25

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PR Comment: https://git.openjdk.org/jdk/pull/23544#issuecomment-2651314171