[clang] [llvm] [WebAssembly] Change to 64-bit table indices on Wasm64 (PR #180649)

[Derek Schuff via cfe-commits]

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dschuff wrote:

Subtargets are per-function (exactly because as you say, functions can have different target attrs). Thinking about this a little more, I think the subtarget could have a different triple e.g. when using the lllc flag to just override the triple in the input IR module. But I don't think it can be different in different functions. I'm still not sure how it could be null but I guess as you say these functions are all currently written as though it could be null, so this logic seems ok.

https://github.com/llvm/llvm-project/pull/180649