[PATCH] D148283: [ExecutionEngine] Support TargetExtType in Interpreter

[Joshua Cranmer via Phabricator via llvm-commits]

jcranmer-intel added a comment.

In D148283#4398589 <https://reviews.llvm.org/D148283#4398589>, @wenju wrote:

> I don't have a test case of global variable with target extension type.

A simple `@global = target("spirv.Event") zeroinitializer` should suffice, combined with a load or store of that global. The point is to make sure that the interpreter can handle a global variable having a target extension type without crashing.

>>> poison value initializers
>
> doe this mean something like "store target("spirv.Event") poison, ptr %event, align 8"?

Yes.

> An alterative approach to this patch is to lower target extension type to its layout type before executing interpreter. I'm proposing this patch as I think it might worth adding natively support of target extension type to interpreter. I don't know if this support will be useful for someone else. There could be cases that target extension type exists in bitcode input of an interpreter.

That's another approach I considered, but I think this approach works a little better. Although you did remind me that there should be a comment somewhere justifying that it is safe to treat the target extension type as its layout type, since the only thing the interpreter is doing is zero-initializing or copying the bits around, and never otherwise inspecting or touching them.


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