This is a reland of commit 2e357c4814
Difference compared to original: Initialize wasm-null object's
payload.
Original change's description:
> [wasm-gc] Introduce wasm null object
>
> We introduce a wasm null object, separate from JS null. Its purpose is
> to support trapping null accesses for wasm objects.
> This will be achieved by allocating a large payload for it (larger than
> any wasm struct) and memory-protecting it (see linked CL). The two null
> objects get mapped to each other at the wasm-JS boundary.
> Since externref objects live on the JS side of the boundary,
> null-related instructions in wasm now need an additional type argument
> to handle the correct null object.
>
> Bug: v8:7748
> Change-Id: I06da00fcd279cc5376e69ab7858e3782f5b5081e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4200639
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#85648}
Bug: v8:7748
Change-Id: I46413d05f0213229f1d19277ae98dbb8df5afdf9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4224011
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#85705}
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