[llvm-dev] How can I use llvm statepoints in a language where some objects are allocated statically and are never collected?

[Dwight Guth via llvm-dev]

I am the developer of a compiler frontend that generates llvm IR. The
language is garbage collected, but currently doesn't have any support for
stack maps yet, which severely limits the places where garbage collection
can occur.

I would like to fix this, and am familiar with the documents online
relating to gc strategies and statepoints in llvm. However, it seems much
of the support for state points is dependent on the assumption that
references are never passed to unmanaged functions, and you never have a
pointer that might be garbage collected, or might not be, and you don't
know at compile time.

Our language violates both of these constraints. There are certain built in
functions in the language that are implemented in c++ and passed direct
pointers to garbage collected values (although garbage collection will
never occur during these functions). There are also some types for which
some constants are allocated statically in the data segment, and other
non-constant values are allocated on the heap. Dereferencing the pointer
can tell me which is which. Finally, some values of pointer type actually
contain integer data, making use of the fact that all real pointers in our
language are aligned, a la ocaml.

Bearing these things in mind, what would I need to do in order to be able
to use the llvm statepoint functionality to generate stack maps? Is it even
practical to do so given the current code?
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