When moving private and workgroup variables into the entry point,
generate pointers to pass as arguments to sub-functions on demand,
instead of upfront. This removes a bunch of unnecessary dereferences
for accesses inside the entry point, and one function variable.
Change-Id: I7d1aabdf14eae33b569b3316dfc0f9fbd288131e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/54300
Auto-Submit: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: James Price <jrprice@google.com>