[Openmp-commits] [PATCH] D142008: [libomptarget] Delay recursive shared library registrations until offload RTLs are loaded

Fri Jan 20 03:31:07 PST 2023

JonChesterfield added a comment.

The HSA thing is intended to do something special for a finite number of specific shared libraries associated with a profiler. They're presumably written expecting HSA to dlopen and dlclose them. That's strange but presumably the profiler has its reasons. It seems like it's going to continue doing that for the profiler.

It'll stop changing unrelated processes if the current patch series gets through the pipeline. The behaviour seen here was introduced with rocm 5.3, so we may want a (hopefully temporary) workaround anyway.

I think the control flow calls dlopen (lazy) on things that are already in the address space and then dlcloses them. We might be able to get this to 'work' by removing attribute constructor / global ctors from some of our codegen.

I'm moderately surprised that ctors are called when dlopen opens something that is already open. Hopefully that's not platform specific.

I'm nervous about this patch as our logic for standing up and tearing down the various shared libraries is already too complicated and this adds a new twist to it. Previous patches in this area tended to make things work on some machines and break on others.

@jhuber can you remember what stopped us from deleting the global ctor embedded in every user TU to set some flag? I think there was some backwards compatibility concern.

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  https://reviews.llvm.org/D142008/new/

https://reviews.llvm.org/D142008