Metal uses a physical addressing mode and buffers are just pointers in
GPU memory that don't have a size. This prevents implementing
OpArrayLength without any additional information. When a shader uses
OpArrayLength on unsized arrays, SPIRV-Cross requires an extra buffer
argument that gets the length of the buffers.
Use that workaround mechanism in the Metal backend by keeping track of
the storage buffer sizes and applying the extra "buffer length buffer"
when a pipeline requires it.
Also adds tests that OpArraySize works in all shader stages.
BUG=dawn:195
Change-Id: I6aa6089aaea85d0589ccad1756e55dd0befefcb5
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/9386
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Corentin Wallez