[msl-out] Replace per_stage_map with per_entry_point_map

[armansito]

The existing per_stage_map field of MSL backend options specifies resource binding maps that apply to all entry points of each stage type. It is useful to have the ability to provide a separate binding index map for each entry point, especially when the same shader module defines multiple entry points of the same stage kind.

This patch introduces a new per_entry_point_map option. When fields are missing in the per-entry-point map, the code falls back to the existing per_stage_map option as before.

[teoxoy]

I'm inclined to say that we replace per_stage_map with the new per_entry_point_map. We'll need this for wgpu soon enough too.

@jimblandy @kvark thoughts?

[armansito]

I left the per_stage_map in place since I thought that might make it easier to transition the code that depends on it but I'm happy to remove it entirely in favor of per_entry_point_map if folks are supportive.

[teoxoy]

Thanks for the PR!

Let's postpone the removal of per_stage_map.
We should also rename PerStageResources to EntryPointResources when we do that to minimize breaking changes.

[codecov-commenter]

Codecov Report

Merging #2237 (00c648e) into master (a5c2cf9) will increase coverage by 12.89%.
The diff coverage is 90.90%.

📣 This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

@@             Coverage Diff             @@
##           master    #2237       +/-   ##
===========================================
+ Coverage   69.14%   82.03%   +12.89%     
===========================================
  Files          77       80        +3     
  Lines       28260    43177    +14917     
===========================================
+ Hits        19539    35421    +15882     
+ Misses       8721     7756      -965     

Impacted Files	Coverage Δ
src/back/msl/writer.rs	90.93% <76.92%> (+16.45%)	⬆️
src/back/msl/mod.rs	83.75% <100.00%> (+5.97%)	⬆️
src/front/wgsl/parse/ast.rs	22.85% <0.00%> (-77.15%)	⬇️
src/front/glsl/token.rs	70.00% <0.00%> (-30.00%)	⬇️
src/back/hlsl/mod.rs	78.33% <0.00%> (-12.30%)	⬇️
src/proc/layouter.rs	87.70% <0.00%> (-7.04%)	⬇️
src/back/wgsl/mod.rs	95.45% <0.00%> (-4.55%)	⬇️
src/front/glsl/variables.rs	76.70% <0.00%> (-3.83%)	⬇️
src/front/glsl/mod.rs	96.61% <0.00%> (-3.39%)	⬇️
src/block.rs	78.57% <0.00%> (-2.68%)	⬇️
... and 72 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[kvark]

@teoxoy sounds reasonable!

[teoxoy]

@armansito since we got a +1 on removing per_stage_map let's do it in this PR - sorry for the back and forth

We can keep get_ep_resources if it makes code nicer and let's also rename PerStageResources to EntryPointResources.

Thank you!

[armansito]

@armansito since we got a +1 on removing per_stage_map let's do it in this PR - sorry for the back and forth

We can keep get_ep_resources if it makes code nicer and let's also rename PerStageResources to EntryPointResources.

Thank you!

No problem! I just force pushed a new change (I erased the previous two commits since they didn't no longer made sense). PTAL!

[teoxoy]

Looks solid! Thanks!