Allocatable automatic deallocation

[kiranchandramohan]

See Fortran 2018 standard: "9.7.3.2 Deallocation of allocatable variables" point 2:

When the execution of a procedure is terminated by execution of a RETURN or END statement, an unsaved
allocatable local variable of the procedure retains its allocation and definition status if it is a function result or a
subobject thereof; otherwise, if it is allocated it will be deallocated.

This is currently not implemented and does not have a TODO. This causes:

• memory leaks in program relying on this feature.
• lack of type finalization for allocatable that require it.

This should be implemented in ConvertVariable.cpp here:

llvm-project/flang/lib/Lower/ConvertVariable.cpp

Line 791 in 658595d

}

, in a similar way to what is done for local objects that require finalization (see the code below if needEndFinalization), except deallocation must be added to the function context cleanups.

[kiranchandramohan]

@jeanPerier is anyone working on this?

[llvmbot]

@llvm/issue-subscribers-flang-ir

[clementval]

@kiranchandramohan I'm not aware of anyone working on this at the moment.

[kiranchandramohan]

Thanks @clementval.

[llvmbot]

@llvm/issue-subscribers-bug

[jeanPerier]

Implemented in #67036