RFR: JDK-8320005 : Allow loading of shared objects with .a extension on AIX [v7]

[Suchismith Roy]

On Wed, 20 Dec 2023 14:30:18 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> Hi,
> 
> some requests and questions:
> 
> * Please modify the JBS title, PR title, and JBS issue text to reflect that this adds an alternative shared object loading path for shared objects on AIX. Something like "Allow loading shared objects with .a extension on AIX". Please describe the new logic in the JBS issue text.
> * Does this really have to be handled in the OpenJDK? What does J9 on AIX do? Could this be done in a simpler way outside OpenJDK, e.g. by providing an *.so variant of the library in question? Where does this library come from?
> * What happens if we accidentally attempt to load a "real" static library, which is also named *.a? Would dlopen() then crash? What would happen?
> * What happens if the original path handed to os::dll_load is already a *.a file? Should the logic then be reversed?
> * We really need regression tests for this.

For some of the question I need to consult the folk working on J9. I will answer a few of them if that gives some clarity. 

> * Please modify the JBS title, PR title, and JBS issue text to reflect that this adds an alternative shared object loading path for shared objects on AIX. Something like "Allow loading shared objects with .an extension on AIX". Please describe the new logic in the JBS issue text. 


Sure working on it.

> * Does this really have to be handled in the OpenJDK? What does J9 on AIX do? Could this be done in a simpler way outside OpenJDK, e.g. by providing an *.so variant of the library in question? Where does this library come from?

I am not sure how J9 handles this. I would have to consult . However as per current observation, this issue does not show up on Semuru. This issue is only happening on Adoptium.  The team that release these file has always released *.a files which work fine for Semuru.

> * What happens if we accidentally attempt to load a "real" static library, which is also named *.a? Would dlopen() then crash? What would happen?


I don't think the problem is with *.a . They would load as the default behaviour of the dlopen. It is only when the dlopen fails for *.so , we give another chance to check for .a file with the same name.

> * What happens if the original path handed to os::dll_load is already a *.a file? Should the logic then be reversed?


I don't think so. We are not modifying the behaviour to handle *.a files here. We are just adding extra checks for *.so files if they fail to load. In the logic , when a load fails, I just check if it is a .so file and perform the loading again.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/16604#issuecomment-1865837275